TY - CONF
A1 - Trappe, Volker
A1 - Nielow, Dustin
T1 - Fatigue loading of sandwich shell test specimens with simulated production imperfections and in-situ NDT
N2 - A shell test bench was developed at BAM 5.3 which allows for static and fatigue testing of curved fiber-reinforced plastic (FRP) structures, during which in-situ the damage state can be non-destructively inspected by thermography and strain-field measurement techniques. Sandwich shell specimens with typical wind turbine blade manufacturing defects were designed and tested. The tested imperfections show a fairly significant reduction (up to 90%) of the shell test specimens‘ lifetime, depending on the type of imperfection. Using the in-situ NDT methods incorporated in the shell test bench, the location and cycle time of the initial defects and the damage evolution was investigated.
T2 - 7. International Conference on Fatigue of Composites
CY - Vicenza, Italy
DA - 04.06.2018
KW - Fatigue of sandwich shell structures
KW - Non-destructive testing
KW - Wind turbine blades
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501275
SP - 1
EP - 7
AN - OPUS4-50127
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Bala, P.
T1 - Refined Calibration Model for Improving the Orientation Precision of Electron Backscatter Diffraction Maps
N2 - For the precise determination of orientations in polycrystalline materials, electron backscatter diffraction (EBSD) requires a consistent calibration of the diffraction geometry in the scanning electron microscope (SEM). In the present paper, the variation of the projection center for the Kikuchi diffraction patterns which are measured by EBSD is calibrated using a projective transformation model for the SEM beam scan positions on the sample. Based on a full pattern matching approach between simulated and experimental Kikuchi patterns, individual projection center estimates are determined on a subgrid of the EBSD map, from which least-square fits to affine and projective transformations can be obtained. Reference measurements on single-crystalline silicon are used to quantify the orientation errors which result from different calibration models for the variation of the projection center.
KW - Scanning electron microscopy
KW - Electron backscatter diffraction
KW - Kikuchi diffraction
KW - Projection center
KW - Orientation precision
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509342
DO - https://doi.org/10.3390/ma13122816
VL - 13
IS - 12
SP - 2816
PB - MDPI
AN - OPUS4-50934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmadi, Samim
A1 - Burgholzer, P.
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
T1 - Super resolution laser line scanning thermography
N2 - In this paper we propose super resolution measurement and post-processing strategies that can be applied in thermography using laser line scanning. The implementation of these techniques facilitates the separation of two closely spaced defects and avoids the expected deterioration of spatial resolution due to heat diffusion. The experimental studies were performed using a high-power laser as heat source in combination with pulsed thermography measurements (step scanning) or with continuous heating measurements (continuous scanning). Our work shows that laser line step scanning as well as continuous scanning both can be used within our developed super resolution (SR) techniques. Our SR techniques make use of a compressed sensing based algorithm in post- processing, the so-called iterative joint sparsity (IJOSP) approach. The IJOSP method benefits from both - the sparse nature of defects in space as well as from the similarity of each measurement. In addition, we show further methods to improve the reconstruction quality e.g. by simple manipulations in thermal image processing such as by considering the effect of the scanning motion or by using different optimization algorithms within the IJOSP approach. These super resolution image processing methods are discussed so that the advantages and disadvantages of each method can be extracted. Our contribution thus provides new approaches for the implementation of super resolution techniques in laser line scanning thermography and informs about which experimental and post-processing parameters should be chosen to better separate two closely spaced defects.
KW - Super resolution
KW - Laser thermography
KW - Compressed sensing
KW - Laser scanning
KW - Joint sparsity
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509796
DO - https://doi.org/10.1016/j.optlaseng.2020.106279
SN - 0143-8166
VL - 134
SP - 106279
PB - Elsevier Ltd.
AN - OPUS4-50979
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rus, J.
A1 - Gustschin, A.
A1 - Mooshofer, H.
A1 - Grager, J.-C.
A1 - Bente, Klaas
A1 - Gaal, Mate
A1 - Pfeiffer, F.
A1 - Grosse, C. U.
T1 - Qualitative comparison of non-destructive methods for inspection of carbon fiber-reinforced polymer laminates
N2 - In the rapidly expanding composite industry, novel inspection methods have been developed in recent years. Particularly promising for air-coupled testing are cellular polypropylene transducers which offer better impedance matching to air than piezoelectric transducers. Furthermore, broadband transmitters (laser-induced ultrasound and thermoacoustic emitters) and receivers (optical microphones) have opened a completely new chapter for advanced contact-free ultra-sound inspection. X-ray dark-field radiography offers a different approach to detect porosity and microcracks, employing small angle X-ray scattering. These innovative ultrasonic and radiographic alternatives were evaluated in comparison with well-established inspection techniques. We applied thirteen different non-destructive methods to inspect the same specimen (a carbon fiber-reinforced polymer laminate with induced impact damage): air-coupled ultrasound testing (using piezoelectric transducers, broadband optical microphones, cellular polypropylene transducers, and a thermoa-
coustic emitter), laser-induced ultrasound testing, ultrasonic immersion testing, phased array ultrasonic testing, optically excited lock-in thermography, and X-ray radiography (projectional absorption and dark-field, tomosynthesis, and micro-computed tomography). The inspection methods were qualitatively characterized by comparing the scan results. The conclusions are advantageous for a decision on the optimal method for certain testing constraints.
KW - Carbon fiber-reinforced polymer
KW - Air-coupled ultrasound
KW - Optically excited lock-in thermography
KW - X-ray micro-computed tomography
KW - X-ray dark-field radiography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509473
DO - https://doi.org/10.1177/0021998320931162
SN - 0021-9983
VL - 54
IS - 27
SP - 4325
EP - 4337
PB - SAGE
AN - OPUS4-50947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tiitta, M.
A1 - Tiitta, V.
A1 - Gaal, Mate
A1 - Heikkinen, J.
A1 - Lappalainen, R.
A1 - Tomppo, L.
T1 - Air-coupled ultrasound detection of natural defects in wood using ferroelectret and piezoelectric sensors
N2 - Air-coupled ultrasound was used for assessing natural defects in wood boards by through-transmission scanning measurements. Gas matrix piezoelectric (GMP) and ferroelectret (FE) transducers were studied. The study also included tests with additional bias voltage with the ferroelectret receivers. Signal analyses, analyses of the measurement dynamics and statistical analyses of the signal parameters were conducted. After the measurement series, the samples were cut from the measurement regions and the defects were analyzed visually from the cross sections. The ultrasound responses were compared with the results of the visual examination of the cross sections. With the additional bias voltage, the ferroelectret measurement showed increased signal-to-noise ratio, which is especially important for air-coupled measurement of high-attenuation materials like wood. When comparing the defect response of GMP and FE sensors, it was found that FE sensors had more sensitive dynamic range, resulting from better s/n ratio and short response pulse. Classification test was made to test the possibility of detecting defects in sound wood. Machine learning methods including decision trees, k-nearest neighbor and support vector machine were used. The classification accuracy varied between 72 and 77% in the tests. All the tested machine learning methods could be used efficiently for the classification.
KW - Air-coupled transducers
KW - Wood
KW - Ultrasound
KW - Ultrasonic imaging
KW - Ferroelectret
KW - Machine learning
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509503
DO - https://doi.org/10.1007/s00226-020-01189-y
SP - 1
EP - 14
PB - Springer
AN - OPUS4-50950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vollert, F.
A1 - Thomas, Maximilian
A1 - Kromm, Arne
A1 - Gibmeier, J.
T1 - Solidification Cracking Assessment of LTT Filler Materials by Means of Varestraint Testing and μCT
N2 - Investigations of the weldability of metals often deal with hot cracking, as one of the most dreaded imperfections during weld fabrication. The hot cracking investigations presented in this paper were carried out as part of a study on the development of low transformation temperature (LTT) weld filler materials. These alloys allow to mitigate tensile residual stresses that usually arise during welding using conventional weld filler materials. By this means, higher fatigue strength and higher lifetimes of the weld can be achieved. However, LTT weld filler materials are for example, high-alloyed Cr/Ni steels that are susceptible to the formation of hot cracks. To assess hot cracking, we applied the standardized modified varestraint transvarestraint hot cracking test (MVT), which is well appropriate to evaluate different base or filler materials with regard to their hot cracking susceptibility. In order to consider the complete material volume for the assessment of hot cracking, we additionally applied microfocus X-ray computer tomography (μCT). It is shown that by a suitable selection of welding and MVT parameter the analysis of the complete 3D hot crack network can provide additional information with regard to the hot cracking model following Prokhorov. It is now possible to determine easy accessible substitute values (e.g., maximum crack depth) for the extent of the Brittleness Temperature Range (BTR) and the minimum critical strain Pmin.
KW - LTT weld filler materials
KW - μCT-analysis
KW - Hot cracking
KW - Varestraint test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509126
DO - https://doi.org/10.3390/ma13122726
VL - 13
IS - 12
SP - 2726
PB - MDPI
AN - OPUS4-50912
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahrbach, M.
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
A1 - Peiner, Erwin
T1 - Calibrating a high-speed contact-resonance profilometer
N2 - A European EMPIR project, which aims to use large-scale piezoresistive microprobes for contact resonance applications, a well-established measurement mode of atomic force microscopes (AFMs), is being funded. As the probes used in this project are much larger in size than typical AFM probes some of the simplifications and assumptions made for AFM probes are not applicable. This study presents a guide on how to systematically create a model that replicates the dynamic behavior of microprobes, including air damping, nonlinear sensitivities, and frequency dependencies. The model is then verified by analyzing a series of measurements.
KW - Piezoresistive cantilever
KW - AFM
KW - contact resonance
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509899
DO - https://doi.org/10.5194/jsss-9-179-2020
VL - 9
SP - 179
EP - 187
PB - Copernicus Publications
AN - OPUS4-50989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Faßbender, Sebastian
A1 - Rodiouchkina, K.
A1 - Vanhaecke, F.
A1 - Meermann, Björn
T1 - Method development for on-line species-specific sulfur isotopic analysis by means of capillary electrophoresis/multicollector ICP-mass spectrometry
N2 - In this work, a method for species-specific isotopic analysis of sulfur via capillary electrophoresis hyphenated on-line with multicollector ICP-MS (CE/MC-ICP-MS) was developed. Correction for the mass bias caused by instrumental mass discrimination was realized via external correction with multiple-injection sample-standard bracketing. By comparing the isotope ratio measurement results obtained using the newly developed on-line CE/MC-ICP-MS method with those obtained via traditional MC-ICP-MS measurement after analyte/matrix separation by anion exchange chromatography for isotopic reference materials and an in-house bracketing standard, the most suitable data evaluation method could be identified. The repeatability for the sulfate-δ34S value (calculated from 18 measurements of a standard conducted over seven measurement sessions) was 0.57‰ (2SD) and thereby only twice that obtained with off-line measurements (0.30‰, n = 68). As a proof of concept for analysis of samples with a real matrix, the determination of the sulfur isotopic composition of naturally present sulfate was performed for different river systems. The CE/MC-ICP-MS results thus obtained agreed with the corresponding off-line MC-ICP-MS results within the 2SD ranges, and the repeatability of consecutive δ34S measurements (n = 3) was between 0.3‰ and 1.3‰ (2SD). Finally, the isotopic analysis of two different S-species in a river water sample spiked with 2-pyridinesulfonic acid (PSA) was also accomplished.
KW - River water sulfate
KW - Environmental speciation
KW - Sulfur isotopes
KW - On-line CE/MC-ICP-MS
KW - Multiple-injection sample-standard bracketing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509549
DO - https://doi.org/10.1007/s00216-020-02781-8
SN - 1618-2642
VL - 412
IS - 23
SP - 5637
EP - 5646
PB - Springer
CY - Berlin, Heidelberg
AN - OPUS4-50954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haller, T.
A1 - Völker, Christoph
A1 - Hartmann, T.
T1 - Machine learning based multi-sensor fusion for the nondestructive testing of corrosion in concrete
N2 - Half-cell potential mapping (HP) is the most popular non-destructive testing method (NDT) for locating corrosion damage in concrete. It is generally accepted that HP is susceptible to environmental factors caused by salt-related deterioration, such as different moisture and chloride gradients. Additional NDT methods are able to identify distinctive areas but are not yet used to estimate more accurate test results. We present a Supervised Machine Learning (SML) based approach to data fusion of seven different signal features to obtain higher quality information. SMLs are methods that explore (or learn) relationships between different (sensor) data from predefined data labels. To obtain a representative, labelled data set we conducted a comprehensive experiment simulating the deterioration cycle of a chloride exposed device in the laboratory. Our data set consists of 18 measurement campaigns, each containing HP, Ground Penetrating- Radar, Microwave Moisture and Wenner resistivity data. We compare the performance of different ML approaches. Many outperform the best single method, HP. We describe the intrinsic challenges posed by a data-driven approach in NDT and show how future work can help overcome them.
T2 - SMAR2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.2019
KW - Machine Learning
KW - NDT
KW - Half-Cell Potential Mapping
KW - Corrosion
KW - Reinforced Concrete
KW - Data Fusion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498563
UR - http://www.ndt.net/?id=24890
VL - 25
IS - 1
SP - 24890-1
EP - 24890-8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-49856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ehlers, Henrik
A1 - Pelkner, Matthias
A1 - Thewes, R.
T1 - Heterodyne Eddy Current Testing Using Magnetoresistive Sensors for Additive Manufacturing Purposes
N2 - In recent years additive manufacturing technologies have become widely popular. For complex functional components or low volume production of workpieces, laser powder bed fusion can be used. High safety requirements, e.g. in the aerospace sector, demand extensive quality control. Therefore, offline non-destructive testing methods like computed tomography are used after manufacturing. Recently, for enhanced profitability and practicality online non-destructive testing methods, like optical tomography have been developed. This paper discusses the applicability of eddy current testing with magnetoresistive sensors for laser powder bed fusion parts. For this purpose, high spatial resolution giant magnetoresistance arrays are utilized for testing in combination with a single wire excitation coil. A heterodyne principle minimizes metrology efforts. This principle is compared to conventional signal processing in an eddy current testing setup using an aluminum test sample with artificial surface defects. To evaluate the influence of the powder used in the manufacturing process on eddy current testing and vice versa, a laser powder bed fusion mock-up made from stainless steel powder (316L) is used with artificial surface defects down to 100 µm. This laser powder bed fusion specimen was then examined using eddy current testing and the underlying principles.
KW - Eddy current testing
KW - Heterodyning
KW - Laser powder bed fusion
KW - Giant magnetoresistance
KW - Additive manufacturing
KW - 316L
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506140
DO - https://doi.org/10.1109/JSEN.2020.2973547
SN - 1530-437X
VL - 20
IS - 11
SP - 5793
EP - 5800
PB - IEEE
AN - OPUS4-50614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thummerer, G.
A1 - Mayr, G.
A1 - Hirsch, Philipp Daniel
A1 - Ziegler, Mathias
A1 - Burgholzer, P.
T1 - Photothermal Image Reconstruction in Opaque Media with Virtual Wave Backpropagation
N2 - Thermographic reconstruction of defects that lie in the bulk of a sample is a difficult task because entropy production during heat diffusion leads to information loss. To reconstruct defects one has to solve an inverse heat conduction problem. The quality of the reconstruction is closely related to the information content of the observed data set that is reflected by the decreasing ability to spatially resolve a defect with growing defect depth. In this work we show a 2D reconstruction of rectangular slots with different width-to-depth ratios in a metallic sample. For this purpose, we apply the virtual wave concept and incorporate positivity and sparsity as prior information to overcome the diffusion-based information loss partially. The reconstruction is based on simulated and experimental pulse thermography data. In the first reconstruction step, we compute a virtual wave field from the surface temperature data. This allows us, in the second step, to use ultrasonic backpropagation methods for image reconstruction.
KW - Virtual wave concept
KW - Thermography
KW - Photothermal Technique
KW - Image reconstruction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506166
DO - https://doi.org/10.1016/j.ndteint.2020.102239
VL - 112
SP - 102239
PB - Elsevier Ltd.
CY - Netherlands
AN - OPUS4-50616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Florian, Camilo
A1 - Wonneberger, R.
A1 - Undisz, A.
A1 - Kirner, Sabrina V.
A1 - Wasmuth, Karsten
A1 - Spaltmann, Dirk
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Chemical effects during the formation of various types of femtosecond laser-generated surface structures on titanium alloy
N2 - In this contribution, chemical, structural, and mechanical alterations in various types of femtosecond laser-generated surface structures, i.e., laser-induced periodic surface structures (LIPSS, ripples), Grooves, and Spikes on titanium alloy, are characterized by various surface analytical techniques, including X-ray diffraction and glow-discharge optical emission spectroscopy. The formation of oxide layers of the different laser-based structures inherently influences the friction and wear performance as demonstrated in oil-lubricated reciprocating sliding tribological tests (RSTTs) along with subsequent elemental mapping by energy-dispersive X-ray analysis. It is revealed that the fs-laser scan processing (790 nm, 30 fs, 1 kHz) of near-wavelength-sized LIPSS leads to the formation of a graded oxide layer extending a few hundreds of nanometers into depth, consisting mainly of amorphous oxides. Other superficial fs-laser-generated structures such as periodic Grooves and irregular Spikes produced at higher fluences and effective number of pulses per unit area present even thicker graded oxide layers that are also suitable for friction reduction and wear resistance. Ultimately, these femtosecond laser-induced nanostructured surface layers efficiently prevent a direct metal-to-metal contact in the RSTT and may act as an anchor layer for specific wear-reducing additives contained in the used engine oil.
KW - Laser-induced oxide layer
KW - Laser-induced periodic surface strctures (LIPSS)
KW - Femtosecond laser processing
KW - Tribology
KW - Surface processing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505660
DO - https://doi.org/10.1007/s00339-020-3434-7
SN - 0947-8396
SN - 1432-0630
VL - 126
IS - 4
SP - 266
PB - Springer Nature Switzerland AG
AN - OPUS4-50566
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Legall, Herbert
A1 - Schwanke, Christoph
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - X-ray radiation protection aspects during ultrashort laser processing
N2 - Ultrashort pulse laser processing of materials allows for precise machining with high accuracy. By increasing the repetition rate to several 100 kHz, laser machining becomes quick and cost-effective. Ultrafast laser processing at high repetition rates and peak intensities above 10^13 W/cm^2 can cause a potential hazard by generation of unwanted x-ray radiation. Therefore, radiation protection must be considered. For 925 fs pulse duration at a center wavelength of 1030 nm, the x-ray emission in air at a repetition rate of 400 kHz was investigated up to a
peak intensity of 2.6 × 10^14 W/cm^2. Based on the presented measurements, the properties of potential shielding materials will be discussed. By extending our previous works, a scaling of the x-ray radiation emission to higher peak intensities up to 10^15 W/cm^2 is described, and emitted x-ray doses are predicted.
KW - Laser ablation
KW - Ultrashort pulse laser processing
KW - Laser-induced x-ray emission
KW - Radiation protection
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505677
DO - https://doi.org/10.2351/1.5134778
VL - 32
IS - 2
SP - 022004
AN - OPUS4-50567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ebel, Kenny
A1 - Bald, Ilko
T1 - Length and Energy Dependence of Low-Energy Electron-Induced Strand Breaks in Poly(A) DNA
N2 - The DNA in living cells can be effectively damaged by high-energy radiation, which can lead to cell death. Through the ionization of water molecules, highly reactive secondary species such as low-energy electrons (LEEs) with the most probable energy around 10 eV are generated, which are able to induce DNA strand breaks via dissociative electron attachment. Absolute DNA strand break cross sections of specific DNA sequences can be efficiently determined using DNA origami nanostructures as platforms exposing the target sequences towards LEEs. In this paper, we systematically study the effect of the oligonucleotide length on the strand break cross section at various irradiation energies. The present work focuses on poly-adenine sequences (d(A4), d(A8), d(A12), d(A16), and d(A20)) irradiated with 5.0, 7.0, 8.4, and 10 eV electrons. Independent of the DNA length, the strand break cross section shows a maximum around 7.0 eV electron energy for all investigated oligonucleotides confirming that strand breakage occurs through the initial formation of negative ion resonances. When going from d(A4) to d(A16), the strand break cross section increases with oligonucleotide length, but only at 7.0 and 8.4 eV, i.e., close to the maximum of the negative ion resonance, the increase in the strand break cross section with the length is similar to the increase of an estimated geometrical cross section. For d(A20), a markedly lower DNA strand break cross section is observed for all electron energies, which is tentatively ascribed to a conformational change of the dA20 sequence. The results indicate that, although there is a general length dependence of strand break cross sections, individual nucleotides do not contribute independently of the absolute strand break cross section of the whole DNA strand. The absolute quantification of sequence specific strand breaks will help develop a more accurate molecular level understanding of radiation induced DNA damage, which can then be used for optimized risk estimates in cancer radiation therapy.
KW - DNA origami
KW - DNA radiation damage
KW - DNA strand breaks
KW - Low-energy electrons
KW - Sequence dependence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503563
DO - https://doi.org/10.3390/ijms21010111
VL - 21
IS - 1
SP - 1
EP - 11
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hu, W.-H
A1 - Tang, D.-H.
A1 - Wang, M.
A1 - Liu, J.-L.
A1 - Li, Z.-H.
A1 - Lu, W.
A1 - Teng, J.
A1 - Said, Samir
A1 - Rohrmann, R. G.
T1 - Resonance Monitoring of a Horizontal Wind Turbine by Strain-Based Automated Operational Modal Analysis
N2 - A strain-based automated operational modal analysis algorithm is proposed to track the long-term dynamic behavior of a horizontal wind turbine under operational conditions.
This algorithm is firstly validated by a scaled wind turbine model, and then it is applied to the dynamic strain responses recorded from a 5 MW wind turbine system. We observed variations in the fundamental frequency and 1f, 3f excitation frequencies due to the mass imbalance of the blades and aerodynamic excitation by the tower dam or tower wake. Inspection of the Campbell diagram revealed that the adverse resonance phenomenon and Sommerfeld effect causing excessive vibrations of the wind tower.
KW - Strain
KW - Automated operational modal analysis
KW - Resonance
KW - Horizontal wind turbine
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503350
DO - https://doi.org/10.3390/en13030579
VL - 13
IS - 3
SP - 579
EP - 584
PB - MDPI
CY - Schweiz, Basel
AN - OPUS4-50335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Drescher, P.
A1 - Fischer, M.
A1 - Fürhapper, C.
A1 - Gunschera, J.
A1 - Hill, R.
A1 - Melcher, E.
A1 - Wegner, R.
A1 - Wilken, U.
A1 - Wittenzellner, J.
T1 - Suitability of analytical methods to determine tebuconazole, propiconazole and permethrin in aged wood samples
N2 - The suitability of common analytical methods for the determination of active substances from wood preservatives in aged wood samples was investigated during an interlaboratory study. Permethrin, propiconazole and tebuconazole were quantified in 1.5 and 8 year-old wood samples by gas chromatography and liquid chromatography. Generally, the applied Methods yielded reliable results for these samples. However, wood components can coelute with propiconazole and tebuconazole during liquid chromatography. Optimization of separation might be required if UV detection is applied.
KW - Wood samples
KW - Biocides
KW - Analytical methods
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503959
DO - https://doi.org/10.1007/s00107-020-01496-y
VL - 78
IS - 2
SP - 271
EP - 279
PB - Springer
CY - Heidelberg
AN - OPUS4-50395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Kranzmann, Axel
T1 - Degradation of AISI 630 exposed to CO2-saturated saline aquifer at ambient pressure and 100 bar
N2 - In general high alloyed steels are suitable as pipe steels for carbon capture and storage technology (CCS), because they provide sufficient resistance against the corrosive environment of CO2-saturated saline aquifer which serves as potential CCS-site in Germany. High alloyed martensitic steel AISI 630 has been proven to be sufficient resistant in corrosive environments, e.g. regarding heat, pressure, salinity of the aquifer, CO2-partial pressure), but reveals a distinct corrosion pattern in CCS environment. Therefore coupons of AISI 630 heat treated using usual protocols were kept at T=60 °C and ambient pressure as well as p=100 bar up to 8000 h in an a) water saturated supercritical CO2 and b) CO2-saturated synthetic aquifer environment similar to on-shore CCS-sites in the Northern German Basin. AISI 630 precipitates a discontinuous ellipsoidal corrosion layer after being exposed for more than 4000 hours. Best corrosion resistance in the CO2-saturated synthetic aquifer environment phase is achieved via normalizing prior to exposure. In water saturated supercritical CO2 tempering at medium temperatures after hardening gives lowest corrosion rates. Corrosion fatigue via push-pull tests with a series of 30 specimens was evaluated at stress amplitudes between 150 MPa and 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ~ 30 Hz). The endurance limit of AISI 630 is reduced by more than 50% when exposed to CCS environment (maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa).
KW - Corrosion Fatigue
KW - High Cycle Fatigue
KW - Steel
KW - Ccs
KW - Co2-Storage
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503783
DO - https://doi.org/10.22587/jasr.2018.14.6.3
SN - 1819-544X
SN - 1816-157X
SP - 11
EP - 17
PB - INSInet Publications
CY - Faisalabad
AN - OPUS4-50378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kondo, M.
A1 - Melzer, Michael
A1 - Karnaushenko, D.
A1 - Uemura, T.
A1 - Yoshimoto, S.
A1 - Aklyama, M.
A1 - Noda, Y.
A1 - Araki, T.
A1 - Schmidt, O. G.
A1 - Sekitani, T.
T1 - Imperceptible magnetic sensor matrix system integrated with organic driver and amplifier circuits
N2 - Artificial electronic skins (e-skins) comprise an integrated matrix of flexible devices arranged on a soft, reconfigurable surface. These sensors must perceive physical interaction spaces between external objects and robots or humans. Among various types of sensors, flexible magnetic sensors and the matrix configuration are preferable for such position sensing. However, sensor matrices must efficiently map the magnetic field with real-time encoding of the positions and motions of magnetic objects. This paper reports an ultrathin magnetic sensor matrix system comprising a 2 × 4 array of magnetoresistance sensors, a bootstrap organic shift register driving the sensor matrix, and organic signal amplifiers integrated within a single imperceptible platform. The system demonstrates high magnetic sensitivity owing to the use of organic amplifiers. Moreover, the shift register enabled real-time mapping of 2D magnetic field distribution.
KW - Imperceptible electronics
KW - Magnetic sensor system
KW - Electronic skin
KW - Organic electronics
KW - Giant magnetoresistance
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503855
DO - https://doi.org/10.1126/sciadv.aay6094
SN - 2375-2548
VL - 6
IS - 4
SP - Paper eaay6094, 1
EP - 10
PB - American Association for the Advancement of Science
AN - OPUS4-50385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Puthiyaveettil, N.
A1 - Kidangan, R.
A1 - Unnikrishnakurup, Sreedhar
A1 - Krishnamurthy, C. V.
A1 - Ziegler, Mathias
A1 - Myrach, Philipp
A1 - Balasubramaniam, K.
T1 - Numerical study of laser line thermography for crack detection at high temperature
N2 - The detection of cracks before the failure is highly significant when it comes to safety-relevant structures. Crack detection in metallic samples at high surface temperature is one of the challenging situation in manufacturing industries.
Laser thermography has already proved its detection capability of surface cracks in metallic samples at room temperature. In this work a continuous wave (CW) laser use to generate a laser, which is using to scan the metal surface with notch.
The corresponding heat distribution on the surface monitored using infrared thermal (IR) camera. A simplified 3D model for laser thermography is developed and validated with experimental results. A dedicated image processing algorithm developed to improve the detectability of the cracks. To understand the dependency of surface temperature, laser power, laser scanning speed etc. in defect detection, we carried out parametric studies with our validated model. Here we Report the capability of laser thermography in crack detection at elevated temperature.
T2 - 14th Quantitative InfraRed Thermography Conference
CY - Berlin, Germany
DA - 25.06.2018
KW - Thermal contrast
KW - Laser Thermography
KW - FEM
KW - Surface cracks
KW - NDT
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499113
DO - https://doi.org/10.21611/qirt.2018.076
SN - 2371-4085
VL - 2018
SP - 685
EP - 686
AN - OPUS4-49911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Comparative analysis of error sources in the determination of wear volumes of oscillating ball-on-plane tests
N2 - The accurate determination of wear volumes is a prerequisite for the study of numerous tribological phenomena. Wear volumes can be measured with different techniques or else be calculated starting from some quantities measured from the wear scar. Advantages and drawbacks of the measuring techniques are shown by means of wear scars and calottes resulting from ball-on-plane tests with 100Cr6 specimens. When measuring wear volumes, white light interferometry results to be one of the most suitable techniques. When wear volumes are calculated, errors result mainly from two sources: (1) the arbitrary choice of one or few line profiles for the determination of the width and of the planimetric wear, and (2) approximations in the calculation, which are even necessary when values of the wear volumes of the single tribological partners and not only the total volume are of interest. The effect of both error sources on the accuracy in the determination of wear volumes is characterized and elucidated by examples. It is found that errors due to approximations are negligible when compared to errors due to the arbitrary choice of one line profile.
KW - Error sources analysis
KW - White light interferometry
KW - Statistical analysis
KW - AFM
KW - Wear
KW - Oscillating ball-on-disc test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508407
DO - https://doi.org/10.3389/fmech.2020.00025
VL - 6
SP - Article 25
AN - OPUS4-50840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kanwal, S.
A1 - Ali, Naveed Zafar
A1 - Hussain, R.
A1 - Shah, F.U.
A1 - Akhter, Z.
T1 - Poly-thiourea formaldehyde based anticorrosion marine coatings on Type 304 stainless steel
N2 - In the present study, hexamethylene diisocyanate (HMDI) encapsulated poly-thiourea formaldehyde (PTF) (10 wt%) coating was developed in an epoxy-polyamine matrix and their anticorrosion studies on Type SS304 stainless steel substrate have been conducted using electrochemistry techniques. The compact and hydrophobic shell wall of PTF proved to be a potent shell wall material for HMDI encapsulation. The effect of temperature and pH values was found to be decisive factor in the synthesis of microcapsules. The PTF microcapsules were synthesized in acidic condition with a pH value of 3. Over 90% of the core fraction is retained in water after 21 days immersion. However, core content decreased with increasing temperature. The capsules were characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Electrochemical Impedance spectroscopy (EIS). Scanning electron microscopic analysis depicts the uniform morphology of coating with a particle size in the range of 1.08 µm–22.06 µm.
The vibrational band at 2271 cm−1 attributed to NCO signal further endorses the successful encapsulation of HMDI into the PTF capsules. Electrochemical testing on steel specifies the appreciable anticorrosion performance of the synthesized poly thiourea formaldehyde (PTF) coating against artificial sea water.
KW - In-situ polymerization
KW - Encapsulation
KW - Thiourea-formaldehyde
KW - Marine corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507932
DO - https://doi.org/10.1016/j.jmrt.2019.12.045
VL - 9
IS - 2
SP - 2146
EP - 2153
PB - Elsevier B.V.
AN - OPUS4-50793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Syc, M.
A1 - Simon, Franz-Georg
A1 - Hyks, J.
A1 - Braga, R.
A1 - Biganzoli, L.
A1 - Costa, G.
A1 - Funari, V.
A1 - Grosso, M.
T1 - Metal recovery from incineration bottom ash: state-of-the-art and recent developments
N2 - Municipal solid waste incineration (MSWI) is one of the leading technologies for municipal solid waste (MSW) treatment in Europe. Incineration bottom ash (IBA) is the main solid residue from MSWI, and its annual European production is about 20 million tons. The composition of IBA depends on the composition of the incinerated waste; therefore, it may contain significant amounts of ferrous and non-ferrous (NFe) metals as well as glass that can be recovered. Technologies for NFe metals recovery have emerged in IBA treatment since the 1990s and became common practice in many developed countries. Although the principles and used apparatus are nearly the same in all treatment trains, the differences in technological approaches to recovery of valuable components from IBA – with a special focus on NFe metals recovery – are summarized in this paper.
KW - Bottom ash
KW - Metal recovery
KW - Waste-to-energy
KW - Non-ferrous metals
KW - Iron scrap
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504927
DO - https://doi.org/10.1016/j.jhazmat.2020.122433
SN - 0304-3894
VL - 393
SP - 122433
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-50492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuerlein, C.
A1 - Andrieux, J.
A1 - Michels, M.
A1 - Lackner, F.
A1 - Chiriac, R.
A1 - Hagner, M.
A1 - Di Michiel, M.
A1 - Meyer, Christian
A1 - Toche, F.
ED - Foley, C. P.
T1 - Effect of the fabrication route on the phase and volume changes during the reaction heat treatment of Nb3Sn superconducting wires
N2 - Accelerator magnets that can reach magnetic fields well beyond the Nb-Ti performance limits are presently being built and developed, using Nb3Sn superconductors. This technology requires reaction heat treatment (RHT) of the magnet coils, during which Nb3Sn is formed from its ductile precursor materials (a “wind and react” approach). The Nb3Sn microstructure and microchemistry are strongly influenced by the conductor fabrication route, and by the Phase changes during RHT. By combining in situ differential scanning calorimetry, high Energy synchrotron x-ray diffraction, and micro-tomography experiments, we have acquired a unique data set that describes in great detail the phase and microstructure changes that take place during the processing of restacked rod process (RRP), powder-in-tube (PIT), and internal tin (IT) Nb3Sn wires. At temperatures below 450 ° the phase evolutions in the three wire types are similar, with respectively solid state interdiffusion of Cu and Sn, Cu6Sn5 formation, and Cu6Sn5 peritectic transformation. Distinct differences in phase evolutions in the wires are found when temperatures exceed 450 °C. The volume changes of the conductor during RHT are a difficulty in the production of Nb3Sn accelerator magnets. We compare the wire diameter changes measured in situ by dilatometry with the phase and void volume evolution of the three types of Nb3Sn wire. Unlike the Nb3Sn wire length changes, the wire diameter evolution is characteristic for each Nb3Sn wire type. The strongest volume increase, of about 5%, is observed in the RRP wire, where the main diameter increase occurs above 600 °C upon Nb3Sn formation.
KW - Nb3Sn
KW - Microstructure
KW - Phase transformations
KW - Volume changes
KW - X-ray diffraction
KW - Differential scanning calorimetry
KW - Synchrotron micro-tomography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505128
DO - https://doi.org/10.1088/1361-6668/ab627c
VL - 33
IS - 3
SP - 034004
PB - IOP Publishing
CY - Bristol (UK)
AN - OPUS4-50512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Florian, Camilo
A1 - Déziel, J.-L.
A1 - Kirner, Sabrina V.
A1 - Siegel, J.
A1 - Bonse, Jörn
T1 - The role of the laser-induced oxide layer in the formation of laser-induced periodic surface structures
N2 - Laser-induced periodic surface structures (LIPSS) are often present when processing solid targets with linearly polarized ultrashort laser pulses. The different irradiation parameters to produce them on metals, semiconductors and dielectrics have been studied extensively, identifying suitable regimes to tailor its properties for applications in the fields of optics, medicine, fluidics and tribology, to name a few. One important parameter widely present when exposing the samples to the high intensities provided by these laser pulses in air environment, that generally is not considered, is the formation of a superficial laser-induced oxide layer. In this paper, we fabricate LIPSS on a layer of the oxidation prone hard-coating material chromium nitride in order to investigate the impact of the laser-induced oxide layer on its formation. A variety of complementary surface analytic techniques were employed, revealing morphological, chemical and structural characteristics of well-known high-spatial frequency LIPSS (HSFL) together with a new type of low-spatial frequency LIPSS (LSFL) with an anomalous orientation parallel to the laser polarization. Based on this input, we performed finite-difference time-domain calculations considering a layered system resembling the geometry of the HSFL along with the presence of a laser-induced oxide layer. The simulations support a scenario that the new type of LSFL is formed at the interface between the laser-induced oxide layer and the non-altered material underneath. These findings suggest that LSFL structures parallel to the polarization can be easily induced in materials that are prone to oxidation.
KW - Laser-induced oxide layer
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface chemistry
KW - Femtosecond laser processing
KW - Nanostructuring
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502530
DO - https://doi.org/10.3390/nano10010147
SN - 2079-4991
VL - 10(1)
IS - Special issue "Laser-generated periodic nanostructures"
SP - 147-1
EP - 147-18
PB - MDPI
CY - Basel
AN - OPUS4-50253
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cubero, A.
A1 - Martínez, E.
A1 - Angurel, L.A.
A1 - de la Fuente, G.F.
A1 - Navarro, R.
A1 - Legall, Herbert
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Effects of laser-induced periodic surface structures on the superconducting properties of Niobium
N2 - It is well known that the use of ultrashort (fs) pulsed lasers can induce the generation of (quasi-) periodic nanostructures (LIPSS, ripples) on the surface of many materials. Such nanostructures have also been observed in sample’s surfaces irradiated with UV lasers with a pulse duration of 300 ps. In this work, we compare the characteristics of these nanostructures on 1-mm and on 25-μm thick niobium sheets induced by 30 fs n-IR and 300 ps UV pulsed lasers. In addition to conventional continuous or burst mode processing configurations, two-dimensional laser beam and line scanning modes have been investigated in this work. The latter allows the processing of large areas with a more uniform distribution of nanostructures at the surface. The influence of the generated nanostructures on the superconducting properties of niobium has also been explored. For this aim, magnetic hysteresis loops have been measured at different cryogenic temperatures to analyse how these laser treatments affect the flux pinning behaviour and, in consequence, the superconductor’s critical current values. It was observed that laser treatments are able to modify the superconducting properties of niobium samples.
T2 - E-MRS Spring Meeting 2019
CY - Nice, France
DA - 27.05.2019
KW - Superconductivity
KW - Laser-induced periodic surface structures (LIPSS)
KW - Niobium
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502541
DO - https://doi.org/10.1016/j.apsusc.2019.145140
SN - 0169-4332
SN - 1873-5584
VL - 508
IS - 1
SP - 145140-1
EP - 145140-7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kowarik, Stefan
A1 - Hussels, Maria-Teresa
A1 - Chruscicki, Sebastian
A1 - Münzenberger, Sven
A1 - Lämmerhirt, A.
A1 - Pohl, P.
A1 - Schubert, M.
T1 - Fiber Optic Train Monitoring with Distributed Acoustic Sensing: Conventional and Neural Network Data Analysis
N2 - Distributed acoustic sensing (DAS) over tens of kilometers of fiber optic cables is well-suited for monitoring extended railway infrastructures. As DAS produces large, noisy datasets, it is important to optimize algorithms for precise tracking of train position, speed, and the number of train cars, The purpose of this study is to compare different data analysis strategies and the resulting parameter uncertainties. We present data of an ICE 4 train of the Deutsche Bahn AG, which was recorded with a commercial DAS system. We localize the train signal in the data either along the temporal or spatial direction, and a similar velocity standard deviation of less than 5 km/h for a train moving at 160 km/h is found for both analysis methods, The data can be further enhanced by peak finding as well as faster and more flexible neural network algorithms. Then, individual noise peaks due to bogie clusters become visible and individual train cars can be counted. From the time between bogie signals, the velocity can also be determined with a lower standard deviation of 0.8 km/h, The analysis methods presented here will help to establish routines for near real-time Train tracking and train integrity analysis.
KW - Artificial neural networks
KW - Distributed fiber optic sensing
KW - Distributed acoustic sensing
KW - Train tracking
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502872
DO - https://doi.org/10.3390/s20020450
VL - 20
IS - 2
SP - 450
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50287
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Cios, G.
A1 - Winkelmann, A.
T1 - Manual measurement of angles in backscattered and transmission Kikuchi diffraction patterns
N2 - A historical tool for crystallographic analysis is provided by the Hilton net, which can be used for manually surveying the crystal lattice as it is manifested by the Kikuchi bands in a gnomonic projection. For a quantitative analysis using the Hilton net, the projection centre as the relative position of the signal source with respect to the detector plane needs to be known. Interplanar angles are accessible with a precision and accuracy which is estimated to be ≤0.3o. Angles between any directions, e.g. zone axes, are directly readable. Finally, for the rare case of an unknown projection-centre position, its determination is demonstrated by adapting an old approach developed for photogrammetric applications.
It requires the indexing of four zone axes [uvw]i in a backscattered Kikuchi diffraction pattern of a known phase collected under comparable geometric conditions.
KW - Electron backscatter diffraction
KW - EBSD
KW - Angle measurement
KW - Gnomonic projections
KW - Kikuchi patterns
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507625
DO - https://doi.org/10.1107/S1600576720000692
VL - 53
SP - 435
EP - 443
AN - OPUS4-50762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adamczyk, Burkart
A1 - Neuhold, S.
A1 - Drissen, P.
A1 - Algermissen, D.
A1 - Presoly, P.
A1 - Sedlazeck, K. P.
A1 - Schenk, J.
A1 - Raith, J. G.
A1 - Pomberger, R.
A1 - Vollprecht, D.
T1 - Tailoring the FeO/SiO2 ratio in electric arc furnace slags to minimize the leaching of Vanadium and Chromium
N2 - Based on recently published research on leaching control mechanisms in electric arc furnace (EAF) slags, it is assumed that a FeO/SiO2 ratio of around one leads to low leached V and Cr concentrations. This ratio influences the mineral phase composition of the slag toward higher amounts of spinel and a lower solubility of calcium silicate phases by suppressing the formation of magnesiowuestite and highly soluble calcium silicate phases. To evaluate this hypothesis, laboratory and scaled up tests in an EAF pilot plant were performed on slag samples characterized by elevated V and Cr leaching and a high FeO/SiO2 ratio. Prior to the melting experiments, the optimum FeO/SiO2 ratio was calculated via FactSageTM. In the melting experiments, the ratio was adjusted by adding quartz sand, which also decreased the basicity (CaO/SiO2) of the slag. As a reference, remelting experiments without quartz sand addition were conducted and additionally, the influence of the cooling rate of the slag was examined. The remelted (without quartz sand) and the remelted modified slags (with quartz sand) were analyzed chemically and mineralogically and the leaching behavior was investigated. The modification of the slags yielded a minimized release of V and Cr, supporting the hypothesis that the FeO/SiO2 ratio influences the mineralogy and the leaching behavior.
KW - Electric arc furnace slags
KW - FactSage calculations
KW - EAF slags
KW - Leaching control mechanisms
KW - Melting experiments
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507748
DO - https://doi.org/10.3390/app10072549
VL - 10
IS - 7
SP - 2549
EP - 2565
AN - OPUS4-50774
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aratsu, K.
A1 - Takeya, R.
A1 - Pauw, Brian Richard
A1 - Hollamby, M.J.
A1 - Kitamoto, Y.
A1 - Shimizu, N.
A1 - Takagi, H.
A1 - Haruki, R.
A1 - Adachi, S.
A1 - Yagai, S.
T1 - Supramolecular copolymerization driven by integrative self-sorting of hydrogen-bonded rosettes
N2 - Molecular recognition to preorganize noncovalently polymerizable supramolecular complexes is a characteristic process of natural supramolecular polymers, and such recognition processes allow for dynamic self-alteration, yielding complex polymer systems with extraordinarily high efficiency in their targeted function. We herein show an example of such molecular recognition-controlled kinetic assembly/disassembly processes within artificial supramolecular polymer systems using six-membered hydrogen-bonded supramolecular complexes (rosettes). Electron-rich and poor monomers are prepared that kinetically coassemble through a temperature-controlled protocol into amorphous coaggregates comprising a diverse mixture of rosettes. Over days, the electrostatic interaction between two monomers induces an integrative self-sorting of rosettes. While the electron-rich monomer inherently forms toroidal homopolymers, the additional electrostatic interaction that can also guide rosette association allows helicoidal growth of supramolecular copolymers that are comprised of an alternating array of two monomers. Upon heating, the helicoidal copolymers undergo a catastrophic transition into amorphous coaggregates via entropy-driven randomization of the monomers in the rosette.
KW - Self-assembly
KW - Coaggregation
KW - Scattering
KW - Simulation
KW - AFM
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506555
DO - https://doi.org/10.1038/s41467-020-15422-6
VL - 11
IS - 1
SP - Article number: 1623
PB - Springer Nature
AN - OPUS4-50655
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vandrich, Jasmina
A1 - Pfeiffer, F.
A1 - Alfaro Espinoza, Gabriela
A1 - Kunte, Hans-Jörg
T1 - Contribution of mechanosensitive channels to osmoadaptation and ectoine excretion in Halomonas elongata
N2 - For osmoadaptation the halophilic bacterium Halomonas elongata synthesizes as its main compatible solute the aspartate derivative ectoine. H. elongata does not rely entirely on synthesis but can accumulate ectoine by uptake from the surrounding environment with the help of the osmoregulated transporter TeaABC. Disruption of the TeaABC-mediated ectoine uptake creates a strain that is constantly losing ectoine to the medium. However, the efflux mechanism of ectoine in H. elongata is not yet understood. H. elongata possesses four genes encoding mechanosensitive channels all of which belong to the small conductance type (MscS). Analysis by qRT-PCR revealed a reduction in transcription of the mscS genes with increasing salinity. The response of H. elongata to hypo- and hyperosmotic shock never resulted in up-regulation but rather in downregulation of mscS transcription. Deletion of all four mscS genes created a mutant that was unable to cope with hypoosmotic shock. However, the knockout mutant grew significantly faster than the wildtype at high salinity of 2 M NaCl, and most importantly, still exported 80% of the ectoine compared to the wildtype. We thus conclude that a yet unknown system, which is independent of mechanosensitive channels, is the major export route for ectoine in H. elongata.
KW - Halomonas elongata
KW - Ectoine
KW - Osmotic shock
KW - Solute excretion
KW - Osmoadaptation
KW - Mechanosensitive channel
KW - MscS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507229
DO - https://doi.org/10.1007/s00792-020-01168-y
VL - 24
SP - 421
EP - 432
PB - Springer
AN - OPUS4-50722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Neitsch, Marcel
A1 - Goedecke, Thomas
T1 - Industrial leak testing of dangerous goods packagings
N2 - The Dangerous Goods Regulations currently do not include limit leakage rates orsensitivity requirements for industrial leak testing procedures that are equivalent tothe bubble test, which is the prescribed test method for design type testing ofdangerous goods packagings. During series production of such packagings, variousmethods are used, which often do not meet the requirements of the bubble test withregard to important criteria.Sensitivity, flow direction, pressure level and automatability are particularly importantfactors when selecting a suitable industrial leak testing method.The following methods are in principle both suitable and equally effective as thebubble test: pressure rise test (vacuum chamber), ultrasonic bubble leak detectionand gas detection methods (pressure technique by accumulation and vacuumchamber technique).To ensure a uniform test level during design type testing and production line leaktesting and therefore a comparable safety level as required by the Dangerous GoodsRegulations, it is necessary to include a more precise specification in these regula-tions. This requires, on the one hand, information about the sensitivity of the bubbletest and, on the other hand, the inclusion of a list of suitable, equally effective indus-trial test methods with their specific boundary conditions.
T2 - 22nd IAPRI World Packaging
CY - Online meeting
KW - Bubble test
KW - Dangerous goods packagings
KW - Industrial leak testing
KW - Leakproofness test
KW - Series production
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507521
DO - https://doi.org/10.1002/pts.2502
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-50752
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkelmann, A.
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Nolze, Gert
A1 - Hielscher, R.
A1 - Koziel, T.
T1 - EBSD orientation analysis based on experimental Kikuchi reference patterns
N2 - Orientation determination does not necessarily require complete knowledge of the local atomic arrangement in a crystalline phase. We present a method for microstructural phase discrimination and orientation analysis of phases for which there is only limited crystallographic information available. In this method, experimental Kikuchi diffraction patterns are utilized to generate a self-consistent master reference for use in the technique of Electron Backscatter Diffraction (EBSD). The experimentally derived master data serves as an application-specific reference in EBSD pattern matching approaches. As application examples, we map the locally varying orientations in samples of icosahedral quasicrystals observed in a Ti40Zr40Ni20 alloy, and we analyse AlNiCo decagonal quasicrystals.
KW - EBSD
KW - Quasicrystal
KW - Crystal orientation
KW - Pattern matching
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507611
DO - https://doi.org/10.1016/j.actamat.2020.01.053
VL - 188
SP - 376
EP - 385
PB - Elsevier Ltd.
AN - OPUS4-50761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hu, W.-H.
A1 - Xu, Z.-M.
A1 - Liu, M.-Y.
A1 - Tang, D.-H.
A1 - Lu, W.
A1 - Li, Z.-H.
A1 - Teng, J.
A1 - Han, X.-H.
A1 - Said, Samir
A1 - Rohrmann, R. G.
T1 - Estimation of the Lateral Dynamic Displacement of High-Rise Buildings underWind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer
N2 - This paper proposes a novel method to estimate the lateral displacement of high-rise structures under wind loads. The coefficient β(x) is firstly derived, reflecting the relation between the structural lateral dynamic displacement and the inclination angle at the height x of a structure. If the angle is small, it is the ratio between the structural fundamental mode shape and its first-order derivative without influence of external loads. Several dynamic experiments of structures are performed based on a laser remote sensing vibrometer and an inclinometer, which shows that the fundamental mode is dominated in the structural displacement response under different types of excitations. Once the coefficient β(x) is curve-fitted by measuring both the structural lateral dynamic displacement and the inclination angle synchronously, the real-time structural lateral displacement under operational conditions is estimated by multiplying the coefficient β(x) with the inclination angle. The advantage of the proposed method is that the coefficient β(x) can be identified by lateral dynamic displacement measured in high resolution by the remote sensing vibrometer, which is useful to reconstruct the displacement accurately by the inclination angle under operational conditions
KW - Inclination angle
KW - High-rise building
KW - Lateral dynamic displacement
KW - Remote sensing vibrometer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506833
DO - https://doi.org/10.3390/rs12071120
VL - 12
IS - 7
SP - 1120
PB - MDPI
CY - 4052 Basel, Schweiz
AN - OPUS4-50683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Bernsmeier, D.
A1 - Schmack, R.
A1 - Häusler, I.
A1 - Hertwig, Andreas
A1 - Kraffert, K.
A1 - Nissen, J.
A1 - Kraehnert, R.
T1 - Colloidal bimetallic platinum–ruthenium nanoparticles in ordered mesoporous carbon films as highly active electrocatalysts for the hydrogen evolution reaction
N2 - Hydrogen features a very high specific energy density and is therefore a promising candidate for clean fuel from renewable resources. Water electrolysis can convert electrical energy into storable and transportable hydrogen gas. Under acidic conditions, platinum is the most active and stable monometallic catalyst for the hydrogen evolution reaction (HER). Yet, platinum is rare and needs to be used efficiently. Here, we report a synthesis concept for colloidal bimetallic platinum–ruthenium and rhodium–ruthenium nanoparticles (PtRuNP, RhRuNP) and their incorporation into ordered mesoporous carbon (OMC) films. The films exhibit high surface area, good electrical conductivity and well-dispersed nanoparticles inside the mesopores. The nanoparticles retain their size, crystallinity and composition during carbonization. In the hydrogen evolution reaction (HER), PtRuNP/OMC catalyst films show up to five times higher activity per Pt than Pt/C/Nafion® and PtRu/C/Nafion® reference catalysts.
KW - Ordered mesoporous carbon
KW - Bimetallic noble metal nanoparticles
KW - Platinum-ruthenium colloid
KW - Electrolysis
KW - Hydrogen evolution reaction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506868
DO - https://doi.org/10.1039/C9CY02285F
SN - 2044-4753
VL - 10
IS - 7
SP - 2057
EP - 2068
PB - Royal Society of Chemistry
AN - OPUS4-50686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blasenbauer, D.
A1 - Huber, F.
A1 - Lederer, J.
A1 - Quina, M.
A1 - Blanc-Biscarat, D.
A1 - Bogush, A.
A1 - Bontempi, E.
A1 - Blondeau, J.
A1 - Chimenos, J.
A1 - Dahlbo, H.
A1 - Fagerqvist, J.
A1 - Giro-Paloma, J.
A1 - Hjelmar, O.
A1 - Hyks, J.
A1 - Keaney, J.
A1 - Lupsea-Toader, M.
A1 - O’Caollai, C.
A1 - Orupõld, K.
A1 - Pajak, T.
A1 - Simon, Franz-Georg
A1 - Svecova, L.
A1 - Syc, M.
A1 - Uvang, R.
A1 - Vaajasaari, K.
A1 - van Caneghem, J.
A1 - van Zomeren, A.
A1 - Vasarevičius, S.
A1 - Wégner, K.
A1 - Fellner, J.
T1 - Legal situation and current practice of waste incineration bottom ash utilisation in Europe
N2 - Almost 500 municipal solid waste incineration plants in the EU, Norway and Switzerland generate about 17.6 Mt/a of incinerator bottom ash (IBA). IBA contains minerals and metals. Metals are mostly separated and sold to the scrap market and minerals are either disposed of in landfills or utilised in the construction sector. Since there is no uniform regulation for IBA utilisation at EU level, countries developed own rules with varying requirements for utilisation. As a result from a cooperation network between European experts an up-to-date overview of documents regulating IBA utilisation is presented. Furthermore, this work highlights the different requirements that have to be considered. Overall, 51 different parameters for the total content and 36 different parameters for the emission by leaching are defined. An analysis of the defined parameter reveals that leaching parameters are significantly more to be considered compared to total content parameters. In order to assess the leaching behaviour nine different leaching tests, including batch tests, up-flow percolation tests and one diffusion test (monolithic materials) are in place.
A further discussion of leaching parameters showed that certain countries took over limit values initially defined for landfills for inert waste and adopted them for IBA utilisation. The overall utilisation rate of IBA in construction works is approximately 54 wt%. It is revealed that the rate of utilisation does not necessarily depend on how well regulated IBA utilisation is, but rather seems to be a result of political commitment for IBA recycling and economically interesting circumstances.
KW - Bottom ash
KW - Leaching tests
KW - Utilisation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500161
DO - https://doi.org/10.1016/j.wasman.2019.11.031
SN - 0956-053X
VL - 102
SP - 868
EP - 883
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-50016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zimmermann, T.
A1 - von der Au, Marcus
A1 - Reese, A.
A1 - Klein, O.
A1 - Hildebrandt, L.
A1 - Pröfrock, D.
T1 - Substituting HF by HBF4 – an optimized digestion method for multi-elemental sediment analysis via ICP-MS/MS
N2 - Determination of elemental mass fractions in sediments plays a major role in evaluating the environmental status of aquatic ecosystems. Herewith, the optimization of a new total digestion protocol and the subsequent analysis of 48 elements in different sediment reference materials (NIST SRM 2702, GBW 07313, GBW 07311 and JMC-2) based on ICP-MS/MS detection is presented. The developed method applies microwave acid digestion and utilizes HBF4 as fluoride source for silicate decomposition. Similar to established protocols based on HF, HBF4 ensures the dissolution of the silicate matrix, as well as other refractory oxides. As HBF4 is not acutely toxic; no special precautions have to be made and digests can be directly measured via ICP-MS without specific sample inlet systems, evaporation steps or the addition of e.g. H3BO3, in order to mask excess HF. Different acid mixtures with and without HBF4 were evaluated in terms of digestion efficiency based on the trace metal recovery. The optimized protocol (5 mL HNO3, 2 mL HCL, 1 mL HBF4) allows a complete dissolution of the analyzed reference materials, as well as quantitative recoveries for a wide variety of certified analytes. Low recoveries for e.g. Sr, Ba and rare earth elements due to fluoride precipitation of HF-based digestions protocols, can be avoided by the usage of HBF4 instead. Based on the usage of high purity HBF4 all relevant trace, as well as matrix elements can be analyzed with sufficiently low LOQs (0.002 μg L−1 for U up to 6.7 μg L−1 for Al). In total, 34 elements were within a recovery range of 80%–120% for all three analyzed reference materials GBW 07313, GBW 07311 and JMC-2. 14 elements were outside a recovery range of 80%–120% for at least one of the analyzed reference materials.
KW - Reference Materials
KW - Sediment
KW - HF free Digestion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510480
DO - https://doi.org/10.1039/D0AY01049A
SP - 1
EP - 10
PB - Royal Society of Chemistry
AN - OPUS4-51048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Simon, Franz-Georg
A1 - Holm, Olaf
ED - Ludwig, C.
ED - Matasci, C.
ED - Edelmann, X.
T1 - Recovery of metals from waste, an example for the resource cycle
N2 - Bottom ash from municipal solid waste incineration (MSWI) consists of eiemental metals in considerable amounts. The fine fraction < 4 mm additionally contains chemically bound metals (oxides, carbonates, Silicates). Separation prospects with techniques as in ore processing (flotation, density separation, bioleaching, hydrothermal solution) are discussed. During alteration after wet extraction mineral material with hydraulic properties form coatings on almost all particles of the bottom ash and complicate separation procedures. ln addition bottom ash from MSWI is a heterogeneaus material. For sufficient enrichment different concerted treatment steps seemed to be essential associated with an uncertainty of economic viability. The utilisation of metal compounds present in bottom ash as secondary raw material depends on the energy- and resource-efficiency of the enrichment processes. Therefore energy and material flow considerations are presented.
KW - Recyclable material
KW - Recycling technology
KW - Waste management
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347572
UR - http://infoscience.epfl.ch/record/213010
SN - 978-3-9521409-6-3
SP - 289
EP - 293
AN - OPUS4-34757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Konersmann, Rainer
T1 - Überdeckungshöhen von Pipelines - Wie tief ist tief genug?
N2 - Ein wesentliches Grundbedürfnis ist die Sicherheit, d. h. die Gewissheit, in einer sicheren Umgebung zu leben und zu arbeiten. Die existenzielle Sicherheit ist eine notwendige Voraussetzung zur Befriedigung aller weiteren notwendigen Bedürfnisse. Auch die Technik ist ohne Sicherheit nicht denkbar. Trotz aller Bemühungen kommt es aber immer wieder zu Unfällen, aus welchen Gründen auch immer. Eine Strategie, Unfälle zu verhindern bzw. deren Eintrittswahrscheinlichkeit zu minimieren ist es, zwischen einem Objekt mit einem hohen Gefährdungspotenzial und seiner Nachbarschaft, Barrieren zu errichten, z. B. durch eine schützende Isolierung, Sicherheitsabstände oder durch eine Erdüberdeckung. Die erdgedeckte Verlegung von Pipelines ist Stand der Technik. Über die Überdeckungshöhen scheint es jedoch verschiedene Auffassungen zu geben. Im folgenden Beitrag werden dazu einige Beispiele vorgestellt.
KW - Rohrleitungen
KW - optimale Überdeckungshöhe
KW - Verkehrslasten
PY - 2016
SN - 2191-0073
VL - 36
IS - 3
SP - 44
EP - 48
PB - Springer-VDI-Verl.
CY - Düsseldorf
AN - OPUS4-35681
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jeromenok, J.
A1 - Böhlmann, W.
A1 - Jäger, Christian
A1 - Weber, J.
T1 - Carbon dioxide adsorption in Betulin-based micro- and macroporous polyurethanes
N2 - Separation of CO2. Microporous polyurethane networks were prepared based on a renewable resource. Betulin, extracted from birch bark, is used as a structure-directing diol monomer in A3-B2 monomers. The resulting microporous networks show very promising CO2/N2 selectivities. The state of adsorbed CO2 is analyzed by in situ NMR spectroscopy, and pure physisorption is proven. The preparation of monolithic materials is demonstrated as well.
KW - Carbon dioxide
KW - Gas adsorption
KW - Microporous polymers
KW - Renewable resources
KW - Solid state NMR spectroscopy
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304431
DO - https://doi.org/10.1002/open.201200045
SN - 2191-1363
VL - 2
IS - 1
SP - 17
EP - 20
PB - Wiley-VCH-Verl.
CY - Weinheim
AN - OPUS4-30443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maiwald, Michael
A1 - Sperling, M.
A1 - Huber, C.
A1 - Hayen, H.
A1 - Teutenberg, T.
A1 - Belder, D.
A1 - Karst, U.
A1 - Hagenhoff, B.
A1 - Vogel, M.
T1 - Prozessanalytik: Spektroskopie und Miniaturisierung
N2 - Forderungen nach höherer Geschwindigkeit und die Komplexität der Fragen geben der analytischen Chemie neue Impulse. So nutzt die Prozessanalytik gepulste Ramanspektrometer, die Elemente Arsen und Quecksilber dominieren die Forschung in der Speziesanalytik, und die Omics-Techniken entwickeln sich zu Multi-Omics-Ansätzen. Ambiente MS-Techniken benötigen keine aufwendige Probenvorbereitung, multidimensionale Trenntechniken werden verstärkt in der Routine eingesetzt, und Chip-basierte Trennungen fallen durch Schnelligkeit auf. Molekülspektroskopie und Massenspektrometrie dominieren die bildgebenden Verfahren, und die Lateralauflösung der ToF-Sekundärionenmassenspektrometrie hat sich bei Oberflächenuntersuchungen verbessert.
KW - Prozessanalytik
KW - Quanten-Kaskadenlaser
KW - Photonendichtewellen-Spektroskopie
KW - Gepulste Ramanspektrometer
KW - Partikelmesstechnik
KW - Prozesssensoren
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-361371
UR - http://onlinelibrary.wiley.com/doi/10.1002/nadc.20164046080/abstract
DO - https://doi.org/10.1002/nadc.20164046080
SN - 1868-0054
VL - 64
IS - 5
SP - 497
EP - 508
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-36137
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prinz, J.
A1 - Heck, Christian
A1 - Ellerik, L.
A1 - Merk, V.
A1 - Bald, Ilko
T1 - DNA origami based Au–Ag-core–shell nanoparticle dimers with single-molecule SERS sensitivity
N2 - DNA origami nanostructures are a versatile tool to arrange metal nanostructures and other chemical entities with nanometer precision. In this way gold nanoparticle dimers with defined distance can be constructed, which can be exploited as novel substrates for surface enhanced Raman scattering (SERS). We have optimized the size, composition and arrangement of Au/Ag nanoparticles to create intense SERS hot spots, with Raman enhancement up to 10^10, which is sufficient to detect single molecules by Raman scattering. This is demonstrated using single dye molecules (TAMRA and Cy3) placed into the center of the nanoparticle dimers. In conjunction with the DNA origami nanostructures novel SERS substrates are created, which can in the future be applied to the SERS analysis of more complex biomolecular targets, whose position and conformation within the SERS hot spot can be precisely controlled.
KW - single molecule spectroscopy
KW - DNA origami
KW - SERS
KW - gold nanoparticles
KW - silver nanoparticles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358761
UR - http://pubs.rsc.org/en/content/articlelanding/2016/nr/c5nr08674d#!divAbstract
DO - https://doi.org/10.1039/C5NR08674D
SP - 5612
EP - 5620
PB - Royal Society of Chemistry
CY - Cambridge, England
AN - OPUS4-35876
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ye, S.
A1 - Loll, B.
A1 - Berger, A.
A1 - Mülow, Ulrike
A1 - Alings, C.
A1 - Wahl, M.
A1 - Koksch, B.
T1 - Fluorine teams up with water to restore inhibitor activity to mutant BPTI
N2 - Introducing fluorine into molecules has a wide range of effects on their physicochemical properties, often desirable but in most cases unpredictable. The fluorine atom imparts the C–F bond with low polarizability and high polarity, and significantly affects the behavior of neighboring functional groups, in a covalent or noncovalent manner. Here, we report that fluorine, present in the form of a single fluoroalkyl amino acid side chain in the P1 position of the well-characterized serine-protease inhibitor BPTI, can fully restore inhibitor activity to a mutant that contains the corresponding hydrocarbon side chain at the same site. High resolution crystal structures were obtained for four BPTI variants in complex with bovine b-trypsin, revealing changes in the stoichiometry and dynamics of water molecules in the S1 subsite. These results demonstrate that the introduction of fluorine into a protein environment can result in “chemical complementation” that has a significantly favorable impact on protein–protein interactions.
KW - serine-protease inhibitor
KW - crystal structures
KW - Peptide synthesis
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358987
DO - https://doi.org/10.1039/C4SC03227F
IS - 9
SP - 5246
EP - 5254
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-35898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Olejko, Lydia
A1 - Cywinski, P.
A1 - Bald, Ilko
T1 - An ion-controlled four-color fluorescent telomeric switch on DNA origami structures
N2 - The folding of single-stranded telomeric DNA into guanine (G) quadruplexes is a conformational change that plays a major role in sensing and drug targeting. The telomeric DNA can be placed on DNA origami nanostructures to make the folding process extremely selective for K+ ions even in the presence of high Na+ concentrations. Here, we demonstrate that the K+-selective G-quadruplex formation is reversible when using a cryptand to remove K+ from the G-quadruplex. We present a full characterization of the reversible switching between single-stranded telomeric DNA and G-quadruplex structures using Förster resonance energy transfer (FRET) between the dyes fluorescein (FAM) and cyanine3 (Cy3). When attached to the DNA origami platform, the G-quadruplex switch can be incorporated into more complex photonic networks, which is demonstrated for a three-color and a four-color FRET cascade from FAM over Cy3 and Cy5 to IRDye700 with G-quadruplex-Cy3 acting as a switchable transmitter.
KW - DNA origami
KW - FRET
KW - Photonic wire
KW - G quadruplex
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-362560
DO - https://doi.org/10.1039/C6NR00119J
SN - 2040-3364
SN - 2040-3372
VL - 8
IS - 19
SP - 10339
EP - 10347
PB - Royal Soc Chemistry
CY - Cambridge, UK
AN - OPUS4-36256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geilert, Sonja
A1 - Vogl, Jochen
A1 - Rosner, M.
A1 - Voerkelius, S.
A1 - Eichert, T.
T1 - Boron isotope fractionation in bell pepper
N2 - Various plant compartments of a single bell pepper plant were studied to verify the variability of boron isotope composition in plants and to identify possible intra-plant isotope fractionation. Boron mass fractions varied from 9.8 mg/kg in the fruits to 70.0 mg/kg in the leaves. Boron (B) isotope ratios reported as δ11B ranged from -11.0 to +16.0 (U ≤ 1.9, k=2) and showed a distinct trend to heavier δ11B values the higher the plant compartments were located in the plant. A fractionation of Δ11Bleaf-roots = 27 existed in the studied bell pepper plant, which represents about about 1/3 of the overall natural boron isotope variation (ca. 80). Two simultaneous operating processes are a possible explanation for the observed systematic intra-plant δ11B variation: 1) B is fixed in cell walls in its tetrahedral form (borate), which preferentially incorporates the light B isotope and the remaining xylem sap gets enriched in the heavy B isotope and 2) certain transporter preferentially transport the trigonal 11B-enriched boric acid molecule and thereby the heavy 11B towards young plant compartments which were situated distal of the roots and typically high in the plant. Consequently, an enrichment of the heavy 11B isotope in the upper young plant parts located at the top of the plant could explain the observed isotope systematic. The identification and understanding of the processes generating systematic intra-plant δ11B variations will potentially enable the use of B isotope for plant metabolism studies.
KW - Boron isotopes
KW - Bell pepper
KW - Boron transport
KW - Boron isotope fractionation
KW - Intra-plant isotope variability
KW - Plants
KW - Bell
KW - Pepper
KW - Isotope fractionation
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-352289
DO - https://doi.org/10.4172/mso.1000101
VL - 1
IS - 1
SP - Article 1000101, 1
EP - 6
AN - OPUS4-35228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Mathies, Helena
A1 - Wegner, R.
T1 - Biocide leaching during field experiments on treated articles
N2 - Background: Biocidal products can be sources of active substances in surface waters caused by weathering of treated articles. Marketing and use of biocidal products can be limited according to the European Biocidal Products Regulation if unacceptable risks to the environment are expected. Leaching of active substances from treated articles was observed in field experiments to obtain information on leaching processes and investigate the suitability of a proposed test method.
Results: Leaching under weathering conditions proceeds discontinuously and tends to decrease with duration of exposure. It mainly depends on the availability of water, but is also controlled by transport processes within the materials and stability of the observed substances. Runoff amount proved to be a suitable basis to compare results from different experiments. Concentrations of substances are higher in runoff collected from vertical surfaces compared to horizontal ones, whereas the leached amounts per surface area are higher from horizontal surfaces. Gaps in mass balances indicate that additional processes such as degradation and evaporation may be relevant to the fate of active substances in treated articles. Leached amounts of substances were considerably higher when the materials were exposed to intermittent water contact under laboratory conditions as compared to weathering of vertically exposed surfaces.
Conclusions: Experiences from the field experiments were used to define parameters of a procedure that is now provided to fulfil requirements of the Biocidal Products Regulation. The experiments confirmed that the amount of water which is in contact with exposed surfaces is the crucial parameter determining leaching of substances.
KW - Biozidprodukte
KW - Farben
KW - Textil
KW - Auswaschung
KW - Freilandtest
KW - Biocidal products
KW - Paints
KW - Textile
KW - Leaching
KW - Field test
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354090
DO - https://doi.org/10.1186/s12302-016-0074-9
VL - 28
IS - 6
SP - 1
EP - 10
PB - Springer
CY - SpringerOpen
AN - OPUS4-35409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hornemann, A.
A1 - Eichert, D.
A1 - Flemig, Sabine
A1 - Ulm, G.
A1 - Beckhoff, B.
T1 - Qualifying label components for effective biosensing using advanced high-throughput SEIRA methodology
N2 - The need for technological progress in bio-diagnostic assays of high complexity requires both fundamental research and constructing efforts on nano-scaled assay recognition elements that can provide unique selectivity and design-enhanced sensitivity features. Nanoparticle induced sensitivity enhancement and its application related to multiplexed capability Surface-Enhanced InfraRed Absorption (SEIRA) assay formats are well suitable for these purposes. The potential of diverse fluorophore–antibody conjugates, being chemisorbed onto low-cost gold nanoparticulate SEIRA substrates, has been explored with respect to their spectral discriminability. These novel biolabels deliver molecular SEIRA fingerprints that have been successfully analyzed by both uni- and multivariate analyzing tools, to discriminate their multiplexing capabilities. We show that this robust spectral encoding via SEIRA fingerprints opens up new opportunities for a fast, reliable and multiplexed high-end screening in biodiagnostics.
KW - SEIRA methodology
KW - bio-diagnostic
KW - nanotechnology
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351389
DO - https://doi.org/10.1039/C4CP05944A
SN - 1463-9076
SN - 1463-9084
VL - 17
IS - 14
SP - 9471
EP - 9479
PB - The Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-35138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Woydt, Mathias
A1 - Mohrbacher, H.
T1 - The tribological and mechanical properties of niobium carbides (NbC) bonded with cobalt of Fe3Al
N2 - The tribological and mechanical properties of niobium carbide bonded with 8 vol.-% (NbC-8Co), 12 vol.-% of cobalt (NbC-12Co) or 12 vol.-% of Fe3Al (NbC-12Fe3Al) are presented. Rotating discs made of metal-bonded niobium carbide were mated against alumina (99.7%) under unlubricated (dry) unidirectional sliding tests (0.1 m/s to 12.0 m/s; 22 °C and 400 C) as well as in oscillation tests (f=20 Hz, Δx=0.2 mm, 2/50/98% rel. humidity, n=105/106 cycles). Microstructure and phase compositions were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where NbC bonded with 8% and 12% Co presented above 7 m/s the lowest wear rates so far in such a benchmark. Binderless NbC (HP-NbC1) and the metal-bonded NbCs exhibited low wear rates under dry sliding associated with P·V high load carrying capacities. NbC-based hard metal bonded with 12 vol.-% of Fe3Al resulted in a higher hardness level than for 12 vol.-% cobalt. The tribological profile established revealed a strong position of NbC-bearing materials under tribological considerations and for closed tribosystems against established reference tribo-couples.
KW - Sliding
KW - Ceramic
KW - Oscillation
KW - Strength
KW - Modulus
KW - High temperatures
KW - Friction
KW - Wear
KW - NbC
KW - Niobium carbide
KW - Cobalt
KW - Fe3Al
KW - Hard metal
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316129
DO - https://doi.org/10.1016/j.wear.2014.09.007
SN - 0043-1648
VL - 321
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-31612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mangelsdorf, Axel
A1 - Blind, K.
T1 - Motives to standardize: Empirical evidence from Germany
N2 - In this paper, we identify the strategic motives of German manufacturing companies in the electrical engineering and machinery industry to be involved in standards development organizations. First, we present the general motives for the formation of strategic alliances and relate them to specific standardization motives. Then, we identify pursuing specific company interests, solving technical problems, knowledge seeking, influencing regulation, and facilitating market access as motives to standardize by means of factor analysis. In a second step, we test hypotheses on the relationship between the importance of strategic motives and firm level variables, e.g. R&D intensity, innovation activities, and firm size. The results reveal that firms in electric engineering and machinery have a particularly strong interest in ensuring industry-friendly design of regulations, which can be achieved by standards. Moreover, the results confirm that small firms also from these two sectors are active in standardization alliances to access knowledge from other involved stakeholders.
KW - Factor analysis
KW - Standardization
KW - Strategic alliances
KW - Knowledge spillovers
KW - Market access
KW - Regulation
KW - Innovation
KW - R&D
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-364586
DO - https://doi.org/10.1016/j.technovation.2016.01.001
SN - 0166-4972
VL - 48-49
SP - 13
EP - 24
PB - Elsevier Science B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-36458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Localized Laser Dispersing of Titanium-Based Particles for Improving the Tribological Performance of Hot Stamping Tools
N2 - Within the scope of this work, a new surface engineering technology named laser implantation has been investigated, in order to improve the tribological performance of hot stamping tools. This technique is based on manufacturing highly wear-resistant, separated, and elevated microfeatures by embedding hard ceramic particles into the tool surface via pulsed laser radiation.
Hence, the topography and material properties of the tool are modified, which influences the thermal and tribological interactions at the blank-die interface. To verify these assumptions and to clarify the cause–effect relations, different titanium-based particles (TiB2, TiC, TiN) were laser-implanted and subsequently analyzed regarding to their geometrical shape and mechanical properties. Afterwards, quenching tests as well as tribological experiments were carried out by using titanium-diboride as the most promising implantation material for reducing the tribological load due to high hardness value of the generated implants. Compared to conventional tooling systems, the modified tool surfaces revealed a significantly higher wear resistance as well as reduced friction forces while offering the possibility to adjust the thermal interactions at the blank-die interface. Based on these results, a tailored tool surface modification can be pursued in future research work, in order to enhance the effectiveness of the hot stamping technology.
KW - Hot stamping
KW - Tribology
KW - Surface modification
KW - Localized laser dispersing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510981
DO - https://doi.org/10.3390/jmmp4030068
VL - 4
IS - 3
SP - 68
PB - MDPI
AN - OPUS4-51098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hobmeier, K.
A1 - Goëss, M. C.
A1 - Sehr, C.
A1 - Schwaminger, S.
A1 - Berensmeier, S.
A1 - Kremling, A.
A1 - Kunte, Hans-Jörg
A1 - Pflüger-Grau, K.
A1 - Marin-Sanguino, A.
T1 - Anaplerotic Pathways in Halomonas elongata: The Role of the Sodium Gradient
N2 - Salt tolerance in the γ-proteobacterium Halomonas elongata is linked to its ability to produce the compatible solute ectoine. The metabolism of ectoine production is of great interest since it can shed light on the biochemical basis of halotolerance as well as pave the way for the improvement of the biotechnological production of such compatible solute. Ectoine belongs to the biosynthetic family of aspartate-derived amino-acids. Aspartate is formed from oxaloacetate, thereby connecting ectoine production to the anaplerotic reactions that refill carbon into the tricarboxylic acid cycle (TCA cycle). This places a high demand on these reactions and creates the need to regulate them not only in response to growth but also in response to extracellular salt concentration. In this work, we combine modeling and experiments to analyze how these different needs shape the anaplerotic reactions in H. elongata. First, the stoichiometric and thermodynamic factors that condition the flux distributions are analyzed, then the optimal patterns of operation for oxaloacetate production are calculated. Finally, the phenotype of two deletion mutants lacking potentially relevant anaplerotic enzymes: phosphoenolpyruvate carboxylase (Ppc) and oxaloacetate decarboxylase (Oad) are experimentally characterized. The results show that the anaplerotic reactions in H. elongata are indeed subject to evolutionary pressures that differ from those faced by other gram-negative bacteria. Ectoine producing halophiles must meet a higher metabolic demand for oxaloacetate and the reliance of many marine bacteria on the Entner-Doudoroff pathway compromises the anaplerotic efficiency of Ppc, which is usually one of the main enzymes fulfilling this role. The anaplerotic flux in H. elongata is contributed not only by Ppc but also by Oad, an enzyme that has not yet been shown to play this role in vivo. Ppc is necessary for H. elongata to grow normally at low salt concentrations but it is not required to achieve near maximal growth rates as long as there is a steep sodium gradient. On the other hand, the lack of Oad presents serious difficulties to grow at high salt concentrations. This points to a shared role of these two enzymes in guaranteeing the supply of oxaloacetate for biosynthetic reactions.
KW - Metabolic flux analysis
KW - Halophilic bacteria
KW - Halomonas elongata
KW - Metabolic modeling
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513124
DO - https://doi.org/10.3389/fmicb.2020.561800
VL - 11
SP - 561800
AN - OPUS4-51312
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
T1 - Application of contact-resonance AFM methods to polymer samples
N2 - Contact-resonance AFM (CR-AFM) has been used in recent years for the measurement of mechanical properties. Compared with other techniques, CR-AFM has a much shorter acquisition time, compensating the incomplete theoretical understanding of the underlying physical phenomena. In the present paper, we propose a procedure, which allows to determine the elastic modulus of the sample as a parameter of the fit of the CR frequency as a function of the load. It is concluded that CR measurements are not appropriate for polymer samples. Major drawbacks are the bad resolution for moduli lower than ca. 10 GPa and the lack of a comprehensive physical model.
KW - Atomic force microscopy
KW - Contact resonance
KW - Mechanical properties
KW - Polymers
KW - Wear
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515621
DO - https://doi.org/10.3762/bjnano.11.154
VL - 11
SP - 1714
EP - 1727
AN - OPUS4-51562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gehrenkemper, Lennart
A1 - Simon, Fabian
A1 - Roesch, Philipp
A1 - Fischer, E.
A1 - von der Au, Marcus
A1 - Pfeifer, Jens
A1 - Cossmer, Antje
A1 - Wittwer, Philipp
A1 - Vogel, Christian
A1 - Simon, Franz-Georg
A1 - Meermann, Björn
T1 - Determination of organically bound fluorine sum parameters in river water samples - Comparison of combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS)
N2 - In this study, we compare combustion ion chromatography (CIC) and high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) with respect to their applicability for determining organically Bound fluorine sum parameters. Extractable (EOF) and adsorbable (AOF) organically bound fluorine as well as total fluorine (TF) were measured in samples fromriver Spree in Berlin, Germany, to reveal the advantages and disadvantages of the two techniques used as well as the two established fluorine sum Parameters AOF and EOF. TF concentrations determined via HR-CS-GFMAS and CIC were comparable between 148 and 270 μg/L. On average, AOF concentrations were higher than EOF concentrations, with AOF making up 0.14–0.81% of TF (determined using CIC) and EOF 0.04–0.28% of TF (determined using HR-CSGFMAS).
The results obtained by the two independent methods were in good agreement. It turned out that HR-CS-GFMAS is a more sensitive and precise method for fluorine analysis compared to CIC. EOF and AOF are comparable tools in Risk evaluation for the emerging pollutants per- and polyfluorinated alkyl substances; however, EOF is much faster to conduct.
KW - High resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS)
KW - Combustion ion chromatography (CIC)
KW - Per- and polyfluorinated alkyl substances (PFASs)
KW - Adsorbable organically bound fluorine (AOF)
KW - Extractable organically bound fluorine (EOF)
KW - Surface waters
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515351
DO - https://doi.org/10.1007/s00216-020-03010-y
SN - 1618-2650
VL - 413
IS - 28
SP - 103
EP - 115
PB - Springer
CY - Berlin
AN - OPUS4-51535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lüth, Peter
A1 - Uhlig, S.
A1 - Frost, K.
A1 - Malow, Marcus
A1 - Michael-Schulz, Heike
A1 - Schmidt, Martin
A1 - Zakel, S.
T1 - CEQAT-DGHS interlaboratory tests for chemical safety: Validation of laboratory test methods by determining the measurement uncertainty and probability of incorrect classification including so-called “Shark profiles”
N2 - Laboratory test results are of vital importance for correctly classifying and labelling chemicals as “hazardous” as defined in the UN Globally Harmonized System (GHS) / EC CLP Regulation or as “dangerous goods” as defined in the UN Recommendations on the Transport of Dangerous Goods. Interlaboratory tests play a decisive role in assessing the reliability of laboratory test results. Interlaboratory tests performed over the last 10 years have examined different laboratory test methods. After analysing the results of these interlaboratory tests, the following conclusions can be drawn:
1. There is a need for improvement and validation for all laboratory test methods examined.
2. To avoid any discrepancy concerning the classification and labelling of chemicals, the use of validated laboratory test methods should be state of the art, with the results accompanied by the measurement uncertainty and (if applicable) the probability of incorrect classification.
This paper addresses the probability of correct/incorrect classification (for example, as dangerous goods) on the basis of the measurement deviation obtained from interlaboratory tests performed by the Centre for quality assurance for testing of dangerous goods and hazardous substances (CEQAT-DGHS) to validate laboratory test methods. This paper outlines typical results (e.g. so-called “Shark profiles” – the probability of incorrect classification as a function of the true value estimated from interlaboratory test data) as well as general conclusions and steps to be taken to guarantee that laboratory test results are fit for purpose and of high quality.
T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE 2020)
CY - Braunschweig, Germany
DA - 27.07.2020
KW - Dangerous goods
KW - Hazardous substances
KW - Interlaboratory test
KW - Test method
KW - Validation
KW - Quality assurance
KW - Measurement uncertainty
KW - Incorrect classification
KW - Shark profile
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515376
UR - https://oar.ptb.de/files/download/5f3e662f4c93901010006dbf
DO - https://doi.org/10.7795/810.20200724
VL - 2020
SP - 50
EP - 61
PB - Open Access Repository der Physikalisch-Technischen Bundesanstalt (PTB-OAR)
CY - Braunschweig
AN - OPUS4-51537
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirtsch, Mona
A1 - Kinne, J.
A1 - Blind, K.
T1 - Exploring the Adoption of the International Information Security Management System Standard ISO/IEC 27001: A Web Mining-Based Analysis
N2 - In the light of digitalization and recent EU policy initiatives, information is an important asset that organizations of all sizes and from all sectors should secure. However, in order to provide common requirements for the implementation of an information security management system, the internationally well-accepted ISO/IEC 27001 standard has not shown the expected growth rate since its publication more than a decade ago.In this article, we apply web mining to explore the adoption of ISO/IEC 27001 through a series of 2664 out of more than 900 000 German firms from the Mannheim Enterprise Panel dataset that refers to this standard on their websites. As a result, we present a “landscape” of ISO/IEC 27001 in Germany, which shows that firms not only seek certifications themselves but often refer on their websites to partners who are certified instead. Consequently, we estimate a probit model and find that larger and more innovative firms are more likely to be certified to ISO/IEC 27001 and that almost half of all certified firms belong to the information and communications technology (ICT) service sector. Based on our findings, we derive implications for policymakers and management and critically assess the suitability of web mining to explore the adoption of management system standards.
KW - Adoption
KW - Information security
KW - Management system standards
KW - Standards
KW - Web mining
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513284
DO - https://doi.org/10.1109/TEM.2020.2977815
VL - 68
IS - 1
SP - 87
EP - 100
AN - OPUS4-51328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Simple and fast prediction of train-induced track forces, ground and building vibrations
N2 - A simple and fast prediction scheme is presented for train induced ground and building vibrations. Simple models such as (1-dimensional) transfer matrices are used for the vehicle-track-soil interaction and for the building-soil interaction. The wave propagation through layered soils is approximated by a frequency-dependent homogeneous half-space. The prediction is divided into the parts “emission” (excitation by railway traffic), “transmission” (wave propagation through the soil) and “immission” (transfer into a building). The link between the modules is made by the excitation force between emission and transmission, and by the free-field vibration between transmission and immission. All formula for the simple vehicle-track, soil and building models are given in this article. The behaviour of the models is demonstrated by typical examples, that is the mitigation of train vibrations by elastic track elements, the low- and high-frequency cut-offs characteristic for layered soils, and the interacting soil, wall and floor resonances of multi-storey buildings. It is shown that the results of the simple prediction models can well represent the behaviour of the more time-consuming detailed models, the finite-element boundary-element models of the track, the wavenumber integrals for the soil, and the three-dimensional finite-element models of the building. In addition, measurement examples are given for each part of the prediction confirming that the methods provide reasonable results. As the prediction models are fast in calculation, many predictions can be done, for example to assess the environmental effect along a new railway line. The simple models have the additional advantage that the user needs to know only a minimum of parameters. So, the prediction is fast and user-friendly, but also theoretically and experimentally well-founded.
KW - Railway induced vibration
KW - Ground vibration
KW - Layered soil
KW - Building response
KW - Excitation forces
KW - Track and vehicle irregularities
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513340
DO - https://doi.org/10.1007/s40534-020-00218-7
SN - 2662-4745
VL - 28
IS - 3
SP - 232
EP - 250
PB - Springer
AN - OPUS4-51334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schirdewahn, S.
A1 - Spranger, Felix
A1 - Hilgenberg, Kai
A1 - Merklein, M.
T1 - Localized dispersing of TiB2 and TiN particles via pulsed laser radiation for improving the tribological performance of hot stamping tools
N2 - The aim of this study is to increase the tribological performance of hot stamping tools by using a laser implantation process. This technique allows the fabrication of separated, elevated and dome-shaped microfeatures on the tool surface in consequence of a localized dispersing of ceramic particles via pulsed laser radiation. Hence, the topography and material properties of the tool are modified, which influences the tribological interactions at the blank-die interface. However, an appropriate selection of ceramic particles is an essential prerequisite, in order to obtain tailored and highly wear resistant surface features. In this regard, different titanium-based hard particles (TiB2 and TiN) were laser-implanted on hot working tool specimens and subsequently tested by means of a modified pin-on-disk test regarding to their wear and friction behavior.
KW - Surface modification
KW - Tribology
KW - Laser implantation
KW - Hot working tool steel
KW - Hot stamping
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514171
DO - https://doi.org/10.1016/j.procir.2020.09.069
VL - 94
SP - 901
EP - 904
PB - Elsevier B.V.
AN - OPUS4-51417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cios, G.
A1 - Nolze, Gert
A1 - Winkelmann, A.
A1 - Tokarski, T.
A1 - Hielscher, R.
A1 - Strzalka, R.
A1 - Buganski, I.
A1 - Wolny, J.
A1 - Bala, P.
T1 - Approximant-based orientation determination of quasicrystals using electron backscatter diffraction
N2 - Orientation mapping of quasicrystalline materials is demonstrated using crystalline approximant structures in the technique of electron backscatter diffraction (EBSD). The approximant-based orientations are symmetrised according to the rotational point group of the quasicrystal, including the visualization of orientation maps using proper colour keys for quasicrystal symmetries. Alternatively, approximant-based orientation data can also be treated using pseudosymmetry post-processing options in the EBSD system software, which enables basic grain size estimations. Approximant-based orientation analyses are demonstrated for icosahedral and decagonal quasicrystals.
KW - EBSD
KW - Quasicrystal
KW - Approximant
KW - Chrystal orientation
KW - Data processing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514221
DO - https://doi.org/10.1016/j.ultramic.2020.113093
VL - 218
SP - 113093
PB - Elsevier B.V.
AN - OPUS4-51422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
T1 - Quo vadis LIPSS? - Recent and future trends on laser-induced periodic surface structures
N2 - Nanotechnology and lasers are among the most successful and active fields of research and technology that have boomed during the past two decades. Many improvements are based on the controlled manufacturing of nanostructures that enable tailored material functionalization for a wide range of industrial applications, electronics, medicine, etc., and have already found entry into our daily life. One appealing approach for manufacturing such nanostructures in a flexible, robust, rapid, and contactless one-step process is based on the generation of laser-induced periodic surface structures (LIPSS). This Perspectives article analyzes the footprint of the research area of LIPSS on the basis of a detailed literature search, provides a brief overview on its current trends, describes the European funding strategies within the Horizon 2020 programme, and outlines promising future directions.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Direct laser interference patterning (DLIP)
KW - Surface functionalization
KW - Literature survey
KW - European funding strategies
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513530
DO - https://doi.org/10.3390/nano10101950
SN - 2079-4991
VL - 10
IS - 10
SP - 1950-1
EP - 1950-19
PB - MDPI
CY - Basel
AN - OPUS4-51353
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weber, A.
A1 - von Randow, M.
A1 - Voigt, A.-L.
A1 - von der Au, Marcus
A1 - Fischer, E.
A1 - Meermann, Björn
A1 - Wagner, M.
T1 - Ingestion and toxicity of microplastics in the freshwater gastropodLymnaea stagnalis: No microplastic-induced effects alone or incombination with copper
N2 - The interaction of microplastics with freshwater biota and their interaction with other stressors is still not very well understood. Therefore, we investigated the ingestion, excretion and toxicity of microplastics in the freshwater gastropod Lymnaea stagnalis.
MP ingestion was analyzed as tissues levels in L. stagnalis after 6–96 h of exposure to 5–90 μm spherical polystyrene (PS) microplastics. To understand the excretion, tissue levels were determined after 24 h of exposure followed by a 12 h–7 d depuration period. To assess the toxicity, snails were exposed for 28 d to irregular PS microplastics (<63 μm, 6.4–100,000 particles mL−1), both alone and in combination with copper as additional stressor. To compare the toxicity of natural and synthetic particles, we also included diatomite particles. Microplastics ingestion and excretion significantly depended on the particle size and the exposure/depuration duration. An exposure to irregular PS had no effect on survival, reproduction, energy reserves and oxidative stress. However, we observed slight effects on immune cell phagocytosis. Exposure to microplastics did not exacerbate the reproductive toxicity of copper. In addition, there was no pronounced difference between the effects of microplastics and diatomite. The tolerance towards microplastics may originate from an adaptation of L. stagnalis to particle-rich environments or a general stress resilience. In conclusion, despite high uptake rates, PS fragments do not appear to be a relevant stressor for stress tolerant freshwater gastropods considering current environmental levels of microplastics.
KW - Lymnaea stagnalis
KW - Microplastic-induced effects
KW - Mixture toxicity
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513551
DO - https://doi.org/10.1016/j.chemosphere.2020.128040
VL - 263
SP - 128040
PB - Elsevier Ltd.
AN - OPUS4-51355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Gräf, S.
T1 - Maxwell Meets Marangoni — A Review of Theories on Laser‐Induced Periodic Surface Structures
N2 - Surface nanostructuring enables the manipulation of many essential surface properties. With the recent rapid advancements in laser technology, a contactless large‐area processing at rates of up to m2 s−1 becomes feasible that allows new industrial applications in medicine, optics, tribology, biology, etc. On the other hand, the last two decades enable extremely successful and intense research in the field of so‐called laser‐induced periodic surface structures (LIPSS, ripples). Different types of these structures featuring periods of hundreds of nanometers only—far beyond the optical diffraction limit—up to several micrometers are easily manufactured in a single‐step process and can be widely controlled by a proper choice of the laser processing conditions. From a theoretical point of view, however, a vivid and very controversial debate emerges, whether LIPSS originate from electromagnetic effects or are caused by matter reorganization. This article aims to close a gap in the available literature on LIPSS by reviewing the currently existent theories of LIPSS along with their numerical implementations and by providing a comparison and critical assessment of these approaches.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Electromagnetic theories
KW - Matter reorganization theories
KW - Surface plasmon polaritons
KW - Self-organization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514089
DO - https://doi.org/10.1002/lpor.202000215
SN - 1863-8899
VL - 14
IS - 10
SP - 2000215-1
EP - 2000215-25
PB - Wiley
CY - Berlin
AN - OPUS4-51408
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koclega, Damian
A1 - Radziszewska, A.
A1 - Dymek, S.
A1 - Morgiel, J.
A1 - Maj, L.
A1 - Kranzmann, Axel
T1 - Improvement of Corrosion Resistance of 13CrMo4-5 Steel by Ni-Based Laser Cladding Coatings
N2 - The 13CrMo4-5 ferritic steel is commonly used in power plants, due to its favorable mechanical properties. According to EN 10028-2, this steel can be used at temperatures up to 570°C because of its creep behavior. The inefficient corrosion resistance limits the application of this steel to lower temperatures depending on the gas temperature and slag formation. Therefore, the application of a highly resistant Ni-based coating is proposed to extend the corrosion resistance of elements made of ferritic steel. The corrosion test was performed in an environment containing a mixture of gases, like O2, COx, and SOx, and deposited ashes with elements, e.g., Na, Cl, Ca, Si, C, Fe, and Al. The exposure time was, respectively, 240 h, 1000 h and 4500 h at a temperature of 600°C. The oxide scale formed on the 13CrMo4-5 steel was significantly thicker than on the IN686 coating. The microstructure and chemical and phase compositions of the oxide scale were investigated using light optical microscopy together with scanning and transmission electron microscopy techniques. Energy dispersive x-ray analyses were performed when appropriate.
KW - Aggressive environments
KW - Corrosion resistance
KW - High - temperature
KW - Inconel 686
KW - Laser cladding
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514289
DO - https://doi.org/10.1007/s11665-020-04867-x
SN - 1059-9495
VL - 29
IS - 6
SP - 3702
EP - 3713
PB - Springer
AN - OPUS4-51428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherb, T.
A1 - Fantin, Andrea
A1 - Checcia, S.
A1 - Stephan-Scherb, Christiane
A1 - Escolástico, S.
A1 - Franz, A.
A1 - Seeger, J.
A1 - Meulenberg, W. A.
A1 - d'Acapito, F.
A1 - Serra, J. M.
T1 - Unravelling the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d mixed ionic electronic conductors
N2 - Mixed ionic electronic conducting ceramics Nd6-yWO12-d (d is the Oxygen deficiency) provide excellent stability in harsh environments containing strongly reactive gases such as CO2, CO, H2, H2O or H2S. Due to this chemical stability, they are promising and cost-efficient candidate materials for gas separation, catalytic membrane reactors and protonic ceramic fuel cell technologies. As in La6-yWO12-d, the ionic/electronic transport mechanism in Nd6-yWO12-d is expected to be largely controlled by the crystal structure, the conclusive determination of which is still lacking. This work presents a crystallographic study of Nd5.8WO12-d and molybdenum-substituted Nd5.7W0.75Mo0.25O12-d prepared by the citrate complexation route. High-resolution synchrotron and neutron powder diffraction data were used in combined Rietveld refinements to unravel the crystal structure of Nd5.8WO12-d and Nd5.7W0.75Mo0.25O12-d. Both investigated samples crystallize in a defect fluorite crystal structure with space group Fm3m and doubled unit-cell parameter due to cation ordering. Mo replacesWat bothWyckoff sites 4a and 48h and is evenly distributed, in contrast with La6-yWO12-d. X-ray absorption spectroscopy as a function of partial pressure pO2 in the near-edge regions excludes oxidation state changes of Nd (Nd3+) and W(W6+) in reducing conditions: the enhanced hydrogen permeation, i.e. ambipolar conduction, observed in Mo-substituted Nd6-yWO12-d is therefore explained by the higher Mo reducibility and the creation of additional – disordered – oxygen vacancies.
KW - Powder diffraction
KW - Mixed conductors
KW - X-ray absorption spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514607
DO - https://doi.org/10.1107/S1600576720012698
VL - 53
SP - 1471
EP - 1483
AN - OPUS4-51460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krautz, M.
A1 - Beyer, L.
A1 - Funk, Alexander
A1 - Waske, Anja
A1 - Weise, B.
A1 - Freudenberger, J.
A1 - Gottschall, T.
T1 - Predicting the dominating factors during heat transfer in magnetocaloric composite wires
N2 - Magnetocaloric composite wires have been studied by pulsed-field measurements up to μ0ΔH = 10 T with a typical rise time of 13 ms in order to evaluate the evolution of the adiabatic temperature change of the core, ΔTad, and to determine the effective temperature change at the surrounding steel jacket, ΔTeff, during the field pulse. An inverse thermal hysteresis is observed for ΔTad due to the delayed thermal transfer. By numerical simulations of application-relevant sinusoidal magnetic field profiles, it can be stated that for field-frequencies of up to two field cycles per second heat can be efficiently transferred from the core to the outside of the jacket. In addition, intense numerical simulations of the temperature change of the core and jacket were performed by varying different parameters, such as frequency, heat capacity, thermal conductivity and interface resistance in order to shed light on their impact on ΔTeff at the outside of the jacket in comparison to ΔTad provided by the core.
KW - Composite
KW - Heat transfer
KW - Numerical simulation
KW - Pulsed magnetic field
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513791
DO - https://doi.org/10.1016/j.matdes.2020.108832
VL - 193
SP - 108832
PB - Elsevier Ltd.
AN - OPUS4-51379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roesch, Philipp
A1 - Vogel, Christian
A1 - Simon, Franz-Georg
T1 - Reductive Defluorination and Mechanochemical Decomposition of Per- and Polyfluoroalkyl Substances (PFASs): From Present Knowledge to Future Remediation Concepts
N2 - Over the past two decades, per- and polyfluoroalkyl substances (PFASs) have emerged as worldwide environmental contaminants, calling out for sophisticated treatment, decomposition and remediation strategies. In order to mineralize PFAS pollutants, the incineration of contaminated material is a state-of-the-art process, but more cost-effective and sustainable technologies are inevitable for the future. Within this review, various methods for the reductive defluorination of PFASs were inspected. In addition to this, the role of mechanochemistry is highlighted with regard to its major potential in reductive defluorination reactions and degradation of pollutants. In order to get a comprehensive understanding of the involved reactions, their mechanistic pathways are pointed out. Comparisons between existing PFAS decomposition reactions and reductive approaches are discussed in detail, regarding their applicability in possible remediation processes. This article provides a solid overview of the most recent research methods and offers guidelines for future research directions.
KW - PFAS
KW - Reductive defluorination
KW - Reductive decomposition
KW - Mechanochemistry
KW - Remediation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513811
DO - https://doi.org/10.3390/ijerph17197242
VL - 17
IS - 19
SP - 1
EP - 22
PB - MDPI AG
CY - Basel
AN - OPUS4-51381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bröcker, S.
A1 - Klaer, R.-H.
A1 - Kockmann, N.
A1 - Maiwald, Michael
T1 - Process Industry United in the Digital World - The current landscape of research for the digitalization of the process industry
N2 - The Tutzing Symposium "100 % digital: survival strategies for the process industry" (see 4.1) in April 2018 was characterized by a great momentum which has been taken up and continued until today. The aim was to implement the ideas from the Tutzing Symposium in a coordinated and targeted manner. For this purpose, development needs as well as the numerous currently planned or already started research and development activities in the context of digitalisation were first compiled and analysed. This resulted in the current research landscape for digitalization in the process industry. It now enables to identify open topics and to translate them into research funding programs as well as to define new projects in the dialogue between users, suppliers and research, which are to be meaningfully interlinked and consolidated with existing projects.
Due to the strong interest in digitalisation, activities are constantly being added, so that this paper can only provide a snapshot of the situation in the period 2019-2020.
KW - Process Industry
KW - Digitalisation
KW - Tutzing Symposion
KW - research landscape
KW - Process Control
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512265
UR - https://processnet.org/en/TAKdigital.html
SP - 1
EP - 15
AN - OPUS4-51226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhuckory, S.
A1 - Wegner, Karl David
A1 - Qiu, X.
A1 - Wu, Y.T.
A1 - Jennings, T. L.
A1 - Incamps, A.
A1 - Hildebrandt, N.
T1 - Triplexed CEA-NSE-PSA Immunoassay Using Time-Gated Terbium-to-Quantum Dot FRET
N2 - Time-gated Förster resonance energy transfer (TG-FRET) between Tb complexes and luminescent semiconductor quantum dots (QDs) provides highly advantageous photophysical properties for multiplexed biosensing. Multiplexed Tb-to-QD FRET immunoassays possess a large potential for in vitro diagnostics, but their performance is often insufficient for their application under clinical conditions. Here, we developed a homogeneous TG-FRET immunoassay for the quantification of carcinoembryonic antigen (CEA), neuron-specific enolase (NSE), and prostatespecific antigen (PSA) from a single serum sample by multiplexed Tb-to-QD FRET. Tb–IgG antibody donor conjugates were combined with compact QD-F(ab’)2 antibody acceptor conjugates with three different QDs emitting at 605, 650, and 705 nm. Upon antibody–antigen–antibody Sandwich complex formation, the QD acceptors were sensitized via FRET from Tb, and the FRET ratios of QD and Tb TG luminescence intensities increased specifically with increasing antigen concentrations.
Although limits of detection (LoDs: 3.6 ng/mL CEA, 3.5 ng/mL NSE, and 0.3 ng/mL PSA) for the triplexed assay were slightly higher compared to the single-antigen assays, they were still in a clinically relevant concentration range and could be quantified in 50 μL serum samples on a B·R·A·H·M·S KRYPTOR Compact PLUS clinical immunoassay plate reader. The simultaneous quantification of CEA, NSE, and PSA at different concentrations from the same serum sample demonstrated actual multiplexing Tb-to-QD FRET immunoassays and the potential of this technology for translation into clinical diagnostics.
KW - Lanthanides
KW - Nanoparticles
KW - Biosensing
KW - Multiplexing
KW - FRET
KW - Fluorescence
KW - PSA
KW - NSE
KW - CEA
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512290
DO - https://doi.org/10.3390/molecules25163679
VL - 25
IS - 16
SP - 3679
PB - MDPI
AN - OPUS4-51229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogl, Jochen
A1 - Rosner, M.
A1 - Kasemann, S. A.
A1 - Kraft, R.
A1 - Meixner, A.
A1 - Noordmann, J.
A1 - Rabb, S.
A1 - Rienitz, O.
A1 - Schuessler, J. A.
A1 - Tatzel, Michael
A1 - Vocke, R. D.
T1 - Intercalibration of Mg isotope delta scales and realisation of SI traceability for Mg isotope amount ratios and isotope delta values
N2 - The continuous improvement of analytical procedures using multi-collector technologies in ICP-mass spectrometry has led to an increased demand for isotope standards with improved homogeneity and reduced measurement uncertainty. For magnesium, this has led to a variety of available standards with different quality levels ranging from artefact standards to isotope reference materials certified for absolute isotope ratios. This required an intercalibration of all standards and reference materials, which we present in this interlaboratory comparison study. The materials Cambridge1, DSM3, ERMAE143, ERM-AE144, ERM-AE145, IRMM-009 and NIST SRM 980 were cross-calibrated with expanded measurement uncertainties (95% confidence level) of less than 0.030‰ for the δ25/24Mg values and less than 0.037‰ for the δ26/24Mg values. Thus, comparability of all magnesium isotope delta (δ) measurements based on these standards and reference materials is established. Further, ERM-AE143 anchors all magnesium δ-scales to absolute isotope ratios and therefore establishes SI traceability, here traceability to the SI base unit mole. This applies especially to the DSM3 scale, which is proposed to be maintained. With ERM-AE144 and ERM-AE145, which are product and educt of a sublimation-condensation process, for the first time a set of isotope reference materials is available with a published value for the apparent triple isotope fractionation exponent θapp, the fractionation relationship ln α(25/24Mg)/ln α(26/24Mg).
KW - Delta scale
KW - Traceability
KW - Scale anchor
KW - Absolute isotope ratio
KW - Comparability
KW - Triple isotope fractionation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511557
DO - https://doi.org/10.1111/ggr.12327
SN - 1751-908X
VL - 44
IS - 3
SP - 439
EP - 457
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-51155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, L.
A1 - von der Au, Marcus
A1 - Zimmermann, T.
A1 - Reese, A.
A1 - Ludwig, J.
A1 - Pröfrock, D.
T1 - A metrologically traceable protocol for the quantification of trace metals in different types of microplastic
N2 - The presence of microplastic (MP) particles in aquatic environments raised concern About possible enrichment of organic and inorganic pollutants due to their specific surface and chemical properties. In particular the role of metals within this context is still poorly understood. Therefore, the aim of this work was to develop a fully validated acid digestion protocol for metal analysis in different polymers, which is a prerequisite to study such interactions.
The proposed digestion protocol was validated using six different certified reference materials in the microplastic size range consisting of polyethylene, polypropylene, acrylonitrile butadiene styrene and polyvinyl chloride. As ICP-MS/MS enabled time-efficient, sensitive and robust analysis of 56 metals in one measurement, the method was suitable to provide mass fractions for a multitude of other elements beside the certified ones (As, Cd, Cr, Hg, Pb, Sb, Sn and Zn). Three different microwaves, different acid mixtures as well as different temperatures in combination with different hold times were tested for optimization purposes.
With the exception of Cr in acrylonitrile butadiene styrene, recovery rates obtained using the optimized protocol for all six certified reference materials fell within a range from 95.9% ± 2.7% to 112% ± 7%. Subsequent optimization further enhanced both precision and recoveries ranging from 103% ± 5% to 107 ± 4% (U; k = 2 (n = 3)) for all certified metals (incl. Cr) in acrylonitrile butadiene styrene. The results clearly show the analytical challenges that come along with metal analysis in chemically resistant plastics. Addressing specific analysis Tools for different sorption scenarios and processes as well as the underlying kinetics was beyond this study’s scope. However, the future application of the two recommended thoroughly validated total acid digestion protocols as a first step in the direction of harmonization of metal analysis in/on MP will enhance the significance and comparability of the generated data. It will contribute to a better understanding of the role of MP as vector for trace metals in the environment.
KW - Microplatic
KW - Digestion
KW - Analytical Chemistry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510727
DO - https://doi.org/10.1371/journal.pone.0236120
VL - 15
IS - 7
SP - e0236120
AN - OPUS4-51072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lone, S. A.
A1 - Muck, M.
A1 - Fosodeder, P.
A1 - Mardare, C.C.
A1 - Florian, Camilo
A1 - Weth, A.
A1 - Krüger, Jörg
A1 - Steinwender, C.
A1 - Baumgartner, W.
A1 - Bonse, Jörn
A1 - Heitz, J.
A1 - Hassel, A.W.
T1 - Impact of Femtosecond Laser Treatment Accompanied with Anodization of Titanium Alloy on Fibroblast Cell Growth
N2 - Herein, Ti6Al4V alloy is surface modified by femtosecond laser ablation. The microstructure image obtained by secondary electron microscopy reveals a combination of micrometer spikes or cones superimposed by nanoripples (laser‐induced periodic surface structures). To make the surface hydrophilic, anodization is performed resulting in further smoothness of microstructure and a final thickness of 35 ± 4 nm is estimated for oxide produced after anodization at 10 V (scan rate = 0.1 V s−1) versus standard hydrogen electrode. The obtained electrochemically active surface area (ECSA) is approximately 8 times larger compared with flat mirror polished Ti6Al4V surface. Combined chemical analysis by Pourbaix diagram and X‐ray photoelectron spectroscopy (XPS) analyses reveal that titanium and aluminum are passivating into TiO2 and Al2O3, but the dissolution of aluminum in the form of solvated ion is inevitable. Finally, cell seeding experiments on anodized and laser‐treated titanium alloy samples show that the growth of murine fibroblast cells is significantly suppressed due to unique surface texture of the laser‐treated and anodized titanium alloy sample.
KW - Anodization
KW - Femtosecond laser ablation
KW - Laser-induced periodic surface structures, LIPSS
KW - Ti6Al4V alloys
KW - X-ray photoelectron spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510263
DO - https://doi.org/https://doi.org/10.1002/pssa.201900838
SN - 1862-6300
SN - 1862-6319
VL - 217
IS - 13
SP - 1900838-1
EP - 1900838-9
PB - WILEY-VCH Verlag
CY - Weinheim, Germany
AN - OPUS4-51026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bucar, K.
A1 - Malet, J.
A1 - Stabile, L.
A1 - Pražnikar, J.
A1 - Seeger, Stefan
A1 - Žitnik, M.
T1 - Statistics of a Sharp GP2Y Low-Cost Aerosol PM Sensor Output Signals
N2 - In this work, we characterise the performance of a Sharp optical aerosol sensor model GP2Y1010AU0F. The sensor was exposed to different environments: to a clean room, to a controlled atmosphere with known aerosol size distribution and to the ambient atmosphere on a busy city street. During the exposure, the output waveforms of the sensor pulses were digitised, saved and a following offline analysis enabled us to study the behaviour of the sensor pulse-by-pulse. A linear response of the sensor on number concentration of the monosized dispersed PSL particles was shown together with an almost linear dependence on particle diameters in the 0.4 to 4 micrometer range.
The gathered data about the sensor were used to predict its response to an ambient atmosphere, which was observed simultaneously with a calibrated optical particle counter.
KW - Aerosol
KW - Partikel
KW - Aerosolsensor
KW - Luftgüte
KW - Umweltmessung
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517466
DO - https://doi.org/10.3390/s20236707
SN - 1424-8220
VL - 20
IS - 23
SP - 6707
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-51746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jaenisch, Gerd-Rüdiger
A1 - Ewert, Uwe
A1 - Waske, Anja
A1 - Funk, Alexander
T1 - Radiographic Visibility Limit of Pores in Metal Powder for Additive Manufacturing
N2 - The quality of additively manufactured (AM) parts is determined by the applied process parameters used and the properties of the feedstock powder. The influence of inner gas pores in feedstock particles on the final AM product is a phenomenon which is difficult to investigate since very few non-destructive measurement techniques are accurate enough to resolve the micropores.
3D X-ray computed tomography (XCT) is increasingly applied during the process chain of AM parts as a non-destructive monitoring and quality control tool and it is able to detect most of the pores.
However, XCT is time-consuming and limited to small amounts of feedstock powder, typically a few milligrams. The aim of the presented approach is to investigate digital radiography of AM feedstock particles as a simple and fast quality check with high throughput. 2D digital radiographs were simulated in order to predict the visibility of pores inside metallic particles for different pore and particle diameters. An experimental validation was performed. It was demonstrated numerically and experimentally that typical gas pores above a certain size (here: 3 to 4.4 µm for the selected X-ray setup), which could be found in metallic microparticles, were reliably detected by digital radiography.
KW - Additive manufacturing
KW - Feedstock powder
KW - Porosity
KW - Digital radiography
KW - Numerical simulation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517880
DO - https://doi.org/10.3390/met10121634
VL - 10
IS - 12
SP - 1634
PB - MDPI
AN - OPUS4-51788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gottlieb, Cassian
A1 - Bohling, Christian
A1 - Wilsch, Gerd
T1 - New possibilities for concrete analysis 4.0 with the Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - In civil engineering the damage assessment of concrete infrastructures is an important task to monitor and ensure the estimated life-time. The aging of concrete is caused by different damage processes like the chloride induced pitting corrosion of the reinforcement. The penetration depth and the concentration of harmful species are crucial factors in the damage assessment. As a highly cost and time-consuming standard procedure, the analysis of concrete drill cores or drilling by wet-chemistry is widely used. This method provides element concentration to the total mass as aggregates and binder are homogenized. In order to provide a method that is capable to detect the element concentration regarding the cement content only, the laser-induced breakdown spectroscopy (LIBS) will be presented. The LIBS method uses a focused pulsed laser on the sample surface to ablate material. The high-power density and the laser-material interaction causes a laser-induced plasma that emits elemental and molecular line emission due to energy transition of the excited species in the plasma during the cooling phase.
As each element provides element-specific line emission, it is in principle possible to detect any element on the periodic table (spectroscopic fingerprint) with one laser shot. In combination with a translation stage the sample under investigation can be spatially resolved using a scan raster with a resolution up to 100 µm (element mapping). Due to the high spatial resolution, the element distribution and the heterogeneity of the concrete can be evaluated. By using chemometrics the non-relevant aggregates can be excluded from the data set and the element concentration can be quantified and referred to a specific solid phase like the binding matrix (cement) only. In order to analyze transport processes like diffusion and migration the twodimensional element distributions can provide deep insight into the transport through the pore space and local enrichments of elements. As LIBS is a multi-elemental method it is also possible to compare the ingress and transport process of different elements like Cl, Na, K, S, C, and Li simultaneously and evaluate cross-correlations between the different ions. Furthermore, the element mapping allows to visualize the transport along cracks. This work will show the state of the art in terms of hardware and software for an automated LIBS system as well as different application for a concrete analysis 4.0. Focus will be the application of LIBS for a fast concrete analysis.
T2 - SMAR 2019
CY - Potsdam, Germany
DA - 27.08.2019
KW - Damage
KW - LIBS
KW - Concrete
KW - Mapping
KW - Chlorine
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517282
UR - https://www.ndt.net/?id=24963
SN - 1435-4934
VL - 25
IS - 1
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-51728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Boehn, B.
A1 - Scholtz, Lena
A1 - Imbihl, R.
T1 - Reactivity and Stability of Ultrathin VOx Films on Pt(111) in Catalytic Methanol Oxidation
N2 - The growth of ultrathin layers of VOx (<12 monolayers) on Pt(111) and the activity of these layers in catalytic methanol oxidation at 10−4 mbar have been studied with low-energy electron difraction, Auger electron spectroscopy, rate measurements, and with photoemission electron microscopy. Reactive deposition of V in O2 at 670 K obeys a Stranski–Krastanov growth mode with a (√3 × √3)R30° structure representing the limiting case for epitaxial growth of 3D-VOx. The activity of VOx/Pt(111) in catalytic methanol oxidation is very low and no redistribution dynamics is observed lifting the initial spatial homogeneity of the VOx layer. Under reaction conditions, part of the surface vanadium difuses into the Pt subsurface region.
Exposure to O2 causes part of the V to difuse back to the surface, but only up to one monolayer of VOx can be stabilized in this way at 10−4 mbar.
KW - Vanadium oxide catalysts
KW - Pt(111)
KW - Supported catalyst
KW - Methanol oxidation
KW - Stranski–Krastanow growth
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517376
DO - https://doi.org/10.1007/s11244-020-01321-z
SN - 1022-5528
VL - 63
IS - 15-18
SP - 1545
EP - 1556
PB - Springer
AN - OPUS4-51737
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raysyan, Anna
A1 - Moerer, R.
A1 - Coesfeld, Bianca
A1 - Eremin, S.
A1 - Schneider, Rudolf
T1 - Fluorescence polarization immunoassay for the determination of diclofenac in wastewater
N2 - Pharmacologically active compounds are often detected in wastewater and surface waters. The nonsteroidal anti-inflammatory drug diclofenac (DCF) was included in the European watch list of substances that requires its environmental monitoring in the member states. DCF may harmfully influence the ecosystem already at concentrations ≤ 1 μg L−1. The fast and easy quantification of DCF is becoming a subject of global importance. Fluorescence polarization immunoassay (FPIA) is a homogeneous mix-and-read method which does not require the immobilization of reagents. FPIA can be performed in one phase within 20–30 min, making it possible to analyse wastewater without any complicated pre-treatment. In this study, new tracermolecules with different structures, linking fluorophores to derivatives of the analyte, were synthesized, three homologous tracers based on DCF, two including a C6 spacer, and one heterologous tracer derived from 5-hydroxy-DCF. The tracer molecules were thoroughly assessed for performance. Regarding sensitivity of the FPIA, the lowest limit of detection reached was 2.0 μg L−1 with a working range up to 870 μg L−1. The method was validated for real wastewater samples against LC-MS/MS as reference method with good agreement of both methods.
KW - Abwasser
KW - Umweltschadstoffe
KW - Antikörper
KW - Antibody
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518398
DO - https://doi.org/10.1007/s00216-020-03058-w
SN - 1618-2642
VL - 413
IS - 4
SP - 999
EP - 107
PB - Springer
CY - Heidelberg
AN - OPUS4-51839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Sascha
A1 - Münzenberger, Sven
A1 - Borchardt, Christopher
T1 - Long-distance fiber optic vibration sensing using convolutional neural networks as real-time denoisers
N2 - A long distance range over tens of kilometers is a prerequisite for a wide range of distributed fiber optic vibration sensing applications. We significantly extend the attenuation-limited distance range by making use of the multidimensionality of distributed Rayleigh backscatter data: Using the wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) technique, backscatter data is measured along the distance and optical frequency dimensions. In this work, we develop, train, and test deep convolutional neural networks (CNNs) for fast denoising of these two-dimensional backscattering results. The very compact and efficient CNN denoiser “DnOTDR” outperforms state-of-the-art image denoising algorithms for this task and enables denoising data rates of 1.2 GB/s in real time. We demonstrate that, using the CNN denoiser, the quantitative strain measurement with nm/m resolution can be conducted with up to 100 km distance without the use of backscatter-enhanced fibers or distributed Raman or Brillouin amplification.
KW - Neural networks
KW - Fiber optic
KW - Vibration sensing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518694
DO - https://doi.org/10.1364/OE.402789
VL - 28
IS - 26
SP - 39325
AN - OPUS4-51869
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sanabria, S. J.
A1 - Baensch, Franziska
A1 - Zauner, M.
A1 - Niemz, P.
T1 - In‑situ quantification of microscopic contributions of individual cells to macroscopic wood deformation with synchrotron computed tomography
N2 - Wood-based composites hold the promise of sustainable construction. Understanding the influence on wood cellular microstructure in the macroscopic mechanical behavior is key for engineering highperformance composites. In this work, we report a novel Individual Cell Tracking (ICT) approach for in-situ quantification of nanometer-scale deformations of individual wood cells during mechanical loading of macroscopic millimeter-scale wood samples. Softwood samples containing > 104 cells were subjected to controlled radial tensile and longitudinal compressive load in a synchrotron radiation micro-computed tomography (SRμCT) setup. Tracheid and wood ray cells were automatically segmented, and their geometric variations were tracked during load. Finally, interactions between microstructure deformations (lumen geometry, cell wall thickness), cellular arrangement (annual growth rings, anisotropy, wood ray presence) with the macroscopic deformation response were investigated. The results provide cellular insight into macroscopic relations, such as anisotropic Poisson effects, and allow direct observation of previously suspected wood ray reinforcing effects.
The method is also appropriate for investigation of non-linear deformation effects, such as buckling and deformation recovery after failure, and gives insight into less studied aspects, such as changes in lumen diameter and cell wall thickness during uniaxial load. ICT provides an experimental tool for direct validation of hierarchical mechanical models on real biological composites.
KW - Wood materials
KW - Micro-comuted tomography (µCT)
KW - Individual cell tracking
KW - Stress-strain behaviour
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518157
DO - https://doi.org/10.1038/S41598-020-78028-4
SN - 2045-2322
VL - 10
SP - 1
EP - 16
PB - Springer nature
AN - OPUS4-51815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmadi, Samim
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Burgholzer, P.
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
T1 - Laser excited super resolution thermal imaging for nondestructive inspection of internal defects
N2 - A photothermal super resolution technique is proposed for an improved inspection of internal defects. To evaluate the potential of the laser-based thermographic technique, an additively manufactured stainless steel specimen with closely spaced internal cavities is used. Four different experimental configurations in transmission, reflection, stepwise and continuous scanning are investigated. The applied image post-processing method is based on compressed sensing and makes use of the block sparsity from multiple measurement events. This concerted approach of experimental measurement strategy and numerical optimization enables the resolution of internal defects and outperforms conventional thermographic inspection techniques.
KW - Super Resolution
KW - Laser Thermography
KW - Non Destructive Testing
KW - Comressed Sensing
KW - Inverse Problem
KW - Thermography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519016
DO - https://doi.org/10.1038/s41598-020-77979-y
VL - 10
IS - 1
SP - 22357
PB - Springer Nature
AN - OPUS4-51901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yu, C.-H.
A1 - Peng, R. L.
A1 - Luzin, V.
A1 - Sprengel, Maximilian
A1 - Calmunger, M.
A1 - Lundgren, J.-E.
A1 - Brodin, H.
A1 - Kromm, Arne
A1 - Moverare, J.
T1 - Thin-wall effects and anisotropic deformation mechanisms of an additively manufactured Ni-based superalloy
N2 - Laser powder bed fusion (LPBF) of Ni-based superalloys shows great potential for high temperature applications, for example, as a burner repair application for gas turbines where the thin-walled structure is important. It motivates this work to investigate the evolution of microstructure and the anisotropic mechanical behavior when plate-like specimens are built with a thickness from 4 mm down to 1 mm. By performing texture analysis using neutron diffraction, a clear transition in fiber texture from <011> to <001> is indicated when the specimen becomes thinner. The residual stress shows no thickness dependence, and at the subsurface the residual stress reaches the same level as the yield strength. Due to the rough as-built surface, a roughness compensation method for mechanical properties of thin-walled structures is outlined and demonstrated. Tensile tests from room temperature up to 700 ◦C have been carried out. Anisotropic mechanical behavior is found at all temperatures, which is strongly related to the anisotropic texture evolution. Stronger texture evolution and grain rotations are discovered when the tensile loading is applied along the building direction. The mechanical behavior has been compared to a wrought material, where the high dislocation density and the subgrain structure of the LPBF material result in a higher yield strength. Combining the statistical texture analysis by neutron diffraction with mechanical testing, EBSD grain orientation mapping and the investigation of dislocation structures using transmission electron microscopy, this work illustrates the significance of texture for the thin-wall effect and anisotropic mechanical behavior of LPBF materials.
KW - Hastelloy X
KW - Hot tensile test
KW - Crystallographic texture
KW - Roughness
KW - Residual stress
KW - Dislocation density
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518759
DO - https://doi.org/10.1016/j.addma.2020.101672
VL - 36
SP - 101672
PB - Elsevier B.V.
AN - OPUS4-51875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heßmann, Jennifer
A1 - Bachmann, Marcel
A1 - Hilgenberg, Kai
T1 - Numerical and experimental investigation of controlled weld pool displacement by electromagnetic forces for joining dissimilar materials
N2 - In order to reduce CO2 emissions, an increasing interest in lightweight construction exists in the automotive industry, especially the multi-material-design approach. The main construction materials here are steels and aluminium alloys. Due to their different physical material properties and limited mutual solubility, these two materials cannot be joined thermally without difficulty. This paper presents a new joining approach for dissimilar materials. It uses electromagnetic displacement of a laser-generated melt pool to produce overlap joints between 1 mm steel (1.0330) and 2 mm aluminium alloy (EN AW 5754). Contactless induced Lorentz forces are generated by an alternating current (AC) magnet system. The controlled displacement of the aluminium alloy melt into the hole of the overlying steel sheet is investigated through numerical and experimental studies. The numerical results are compared with cross sections and thermocouple measurements. For the first time, it is possible to achieve a reproducible controlled melt pool displacement on thin sheets to produce overlap joints between dissimilar materials.
KW - Displacement
KW - Laser beam welding
KW - Dissimilar materials
KW - Joining technology
KW - Electromagnetic field
KW - Lorentz force
KW - Numerical investigation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516640
DO - https://doi.org/10.3390/met10111447
VL - 10
IS - 11
SP - 1447
EP - 1462
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-51664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Anja
A1 - Possling, A.
A1 - Malysheva, N.
A1 - Yousef, K. P.
A1 - Herbst, S.
A1 - von Kleist, M.
A1 - Hengge, R.
T1 - Local c-di-GMP signaling in the control of synthesis of the E. coli biofilm exopolysaccharide pEtN-cellulose
N2 - In many bacteria, the biofilm-promoting second messenger c-di-GMP is produced and degraded by multiple diguanylate cyclases (DGC) and phosphodiesterases (PDE), respectively. High target specificity of some of these enzymes has led to theoretical concepts of "local" c-di-GMP signaling. In Escherichia coli K-12, which has 12 DGCs and 13 PDEs, a single DGC, DgcC, is specifically required for the biosynthesis of the biofilm exopolysaccharide pEtN-cellulose without affecting the cellular c-di-GMP pool, but the mechanistic basis of this target specificity has remained obscure. DGC activity of membrane-associated DgcC, which is demonstrated in vitro in nanodiscs, is shown to be necessary and sufficient to specifically activate cellulose biosynthesis in vivo. DgcC and a particular PDE, PdeK (encoded right next to the cellulose operon), directly interact with cellulose synthase subunit BcsB and with each other, thus establishing physical proximity between cellulose synthase and a local source and sink of c-di-GMP. This arrangement provides a localized, yet open source of c-di-GMP right next to cellulose synthase subunit BcsA, which needs allosteric activation by c-di-GMP. Through mathematical modeling and simulation, we demonstrate that BcsA binding from the low cytosolic c-di-GMP pool in E. coli is negligible, whereas a single c-di-GMP molecule that is produced and released in direct proximity to cellulose synthase increases the probability of c-di-GMP binding to BcsA several hundred-fold. This local c-di-GMP signaling could provide a blueprint for target-specific second messenger signaling also in other bacteria where multiple second messenger producing and degrading enzymes exist.
KW - Biofilm
KW - Cellulose synthase
KW - Bacterial second messenger
KW - C-di-GMP
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511214
DO - https://doi.org/10.1016/j.jmb.2020.06.006
SN - 0022-2836
VL - 432
IS - 16
SP - 4576
EP - 4595
PB - Elsevir Ltd.
AN - OPUS4-51121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sajulga, R.
A1 - Easterly, C.
A1 - Riffle, M.
A1 - Mesuere, B.
A1 - Muth, Thilo
A1 - Mehta, S.
A1 - Kumar, P.
A1 - Johnson, J.
A1 - Gruening, B.
A1 - Schiebenhoefer, H.
A1 - Kolmeder, C.
A1 - Fuchs, S.
A1 - Nunn, B.
A1 - Rudney, J.
A1 - Griffin, T.
A1 - Jagtap, P.
T1 - Survey of metaproteomics software tools for functional microbiome analysis
N2 - To gain a thorough appreciation of microbiome dynamics, researchers characterize the functional relevance of expressed microbial genes or proteins. This can be accomplished through metaproteomics, which characterizes the protein expression of microbiomes. Several software tools exist for analyzing microbiomes at the functional level by measuring their combined proteome-level response to environmental perturbations. In this survey, we explore the performance of six available tools, to enable researchers to make informed decisions regarding software choice based on their research goals. Tandem mass spectrometry-based proteomic data obtained from dental caries plaque samples grown with and without sucrose in paired biofilm reactors were used as representative data for this evaluation. Microbial peptides from one sample pair were identified by the X! tandem search algorithm via SearchGUI and subjected to functional analysis using software tools including eggNOG-mapper, MEGAN5, MetaGOmics, MetaProteomeAnalyzer (MPA), ProPHAnE, and Unipept to generate functional annotation through Gene Ontology (GO) terms. Among these software tools, notable differences in functional annotation were detected after comparing differentially expressed protein functional groups. Based on the generated GO terms of these tools we performed a peptide-level comparison to evaluate the quality of their functional annotations. A BLAST analysis against the NCBI non-redundant database revealed that the sensitivity and specificity of functional annotation varied between tools. For example, eggNOG-mapper mapped to the most number of GO terms, while Unipept generated more accurate GO terms. Based on our evaluation, metaproteomics researchers can choose the software according to their analytical needs and developers can use the resulting feedback to further optimize their algorithms. To make more of these tools accessible via scalable metaproteomics workflows, eggNOG-mapper and Unipept 4.0 were incorporated into the Galaxy platform.
KW - Bioinformatics
KW - Metaproteomics
KW - Mass spectrometry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516358
DO - https://doi.org/10.1371/journal.pone.0241503
SP - e0241503
AN - OPUS4-51635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogl, Jochen
T1 - The triple-isotope calibration approach: a universal and standard-free calibration approach for obtaining absolute isotope ratios of multi-isotopic elements
N2 - The theory of a new calibration approach for obtaining absolute isotope ratios of multi-isotopic elements without the use of any standard has been developed. The calibration approach basically uses the difference in the instrumental isotope fractionation of two different types of mass spectrometers, leading to two different fractionation lines in a three-isotope diagram. When measuring the same sample with both mass spectrometers, the different fractionation lines have one point in common: this is the ‘true’ logarithmized isotope ratio pair of the sample. Thus, the intersection of both fractionation lines provides us with the absolute isotope ratios of the sample. This theory has been tested in practice by measuring Cd and of Pb isotope ratios in the certified reference materials BAM-I012 and NIST SRM981 by thermal ionization mass spectrometry and by inductively coupled plasma mass spectrometry while varying the ionization conditions for both mass spectrometers. With this experiment, the theory could be verified, and absolute isotope ratios were obtained, which were metrologically compatible with the certified isotope ratios. The so-obtained absolute isotope ratios are biased by − 0.5% in average, which should be improved with further developments of the method. This calibration approach is universal, as it can be applied to all elements with three or more isotopes and it is not limited to the type of mass spectrometers applied; it can be applied as well to secondary ion mass spectrometry or others. Additionally, this approach provides information on the fractionation process itself via the triple-isotope fractionation exponent θ.
KW - Triple isotope fractionation
KW - Absolute isotope ratio
KW - Mass spectrometry
KW - Calibration
KW - Uncertainty
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516364
DO - https://doi.org/10.1007/s00216-020-03050-4
VL - 413
IS - 3
SP - 821
EP - 826
PB - Springer Verlag
AN - OPUS4-51636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichel, V. E.
A1 - Matuszak, J.
A1 - Bente, Klaas
A1 - Heil, T.
A1 - Kraupner, A.
A1 - Dutz, S.
A1 - Cicha, I.
A1 - Faivre, D.
T1 - Magnetite-Arginine Nanoparticles as a Multifunctional Biomedical Tool
N2 - Iron oxide nanoparticles are a promising platform for biomedical applications, both in terms of diagnostics and therapeutics. In addition, arginine-rich polypeptides are known to penetrate across cell membranes. Here, we thus introduce a system based on magnetite nanoparticles and the polypeptide poly-l-arginine (polyR-Fe3O4). We show that the hybrid nanoparticles exhibit a low cytotoxicity that is comparable to Resovist®, a commercially available drug. PolyR-Fe3O4 particles perform very well in diagnostic applications, such as magnetic particle imaging (1.7 and 1.35 higher signal respectively for the 3rd and 11th harmonic when compared to Resovist®), or as contrast agents for magnetic resonance imaging (R2/R1 ratio of 17 as compared to 11 at 0.94 T for Resovist®). Moreover, these novel particles can also be used for therapeutic purposes such as hyperthermia, achieving a specific heating power ratio of 208 W/g as compared to 83 W/g for Feridex®, another commercially available product. Therefore, we envision such materials to play a role in the future theranostic applications, where the arginine ability to deliver cargo into the cell can be coupled to the magnetite imaging properties and cancer fighting activity.
KW - Iron oxide
KW - Nanoparticle
KW - Theranostics
KW - MRI
KW - Hyperthermia
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515993
DO - https://doi.org/10.3390/nano10102014
VL - 10
IS - 10
SP - 2014
PB - MDPI
AN - OPUS4-51599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Direct detection based φOTDR using the Kramers-Kronig receiver
N2 - A Kramers-Kronig (KK) receiver is applied to a phase-sensitive optical time domain reflectometry based on direct detection. An imbalanced Mach-Zehnder interferometer with a 2× 2 coupler is used in sensing system to encode the phase information into optical intensity. The directly obtained signal is treated as the in-phase component, and the KK receiver provides the quadrature component by Hilbert transform of the obtained signal, so that the optical phase can be retrieved by IQ demodulation. The working principle is well explained, and the obtained phase variance is theoretically analyzed. The experiment demonstrates the functionality of the sensor and validates the theoretical analysis.
KW - Kramers-Kronig detector
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516803
UR - https://www.osapublishing.org/oe/fulltext.cfm?uri=oe-28-24-37058&id=442839
DO - https://doi.org/10.1364/OE.405723
VL - 28
IS - 24
SP - 37058
EP - 37068
PB - Optical Society of America
AN - OPUS4-51680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholz, Philipp
A1 - Putna-Nimane, I.
A1 - Barda, I.
A1 - Liepina-Leimane, I.
A1 - Strode, E.
A1 - Kileso, A.
A1 - Esiukova, E.
A1 - Chubarenko, B.
A1 - Purina, I.
A1 - Simon, Franz-Georg
T1 - Environmental impact of geosynthetics in coastal protection
N2 - Geosynthetic materials are applied in measures for coastal protection. Weathering or any damage of constructions, as shown by a field study in Kaliningrad Oblast (Russia), could lead to the littering of the beach or the sea (marine littering) and the discharge of possibly harmful additives into the marine environment. The ageing behavior of a widely used geotextile made of polypropylene was studied by artificial accelerated ageing in water-filled autoclaves at temperatures of 30 to 80 °C and pressures of 10 to 50 bar. Tensile strength tests were used to evaluate the progress of ageing, concluding that temperature rather than pressure was the main factor influencing the ageing of geotextiles. Using a modified Arrhenius equation, it was possible to calculate the half-life for the loss of 50% of the strain, which corresponds to approximately 330 years. Dynamic surface leaching and ecotoxicological tests were performed to determine the possible release of contaminants. No harmful effects on the test organisms were observed.
KW - Geosynthetics
KW - Geotextiles
KW - Dynamic surface leaching test
KW - Artificial ageing
KW - Marine littering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520576
DO - https://doi.org/10.3390/ma14030634
SN - 1996-1944
VL - 14
IS - 3 (Special issue: Measurement of the environmental impact of materials)
SP - 634-1
EP - 634-13
PB - MDPI
CY - Basel
AN - OPUS4-52057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abis, M.
A1 - Bruno, M.
A1 - Kuchta, K.
A1 - Simon, Franz-Georg
A1 - Grönholm, R.
A1 - Hoppe, M.
A1 - Fiore, S.
T1 - Assessment of the Synergy between Recycling and Thermal Treatments in Municipal Solid Waste Management in Europe
N2 - In 2018, the production of Municipal SolidWaste (MSW) in EU-28 reached 250.6 Mt, with the adoption of different management strategies, involving recycling (48 wt %), incineration and thermal valorization (29 wt %) and landfilling (23 wt %). This work was based on the analysis of the baseline situation of MSW management in EU-28 in 2018, considering its progress in 2008–2018, and discussed the possible improvement perspectives based on a framework involving incineration and recycling as the only possible alternatives, specifically evaluating the capability of already-existing incineration plants to fulfill the EU needs in the proposed framework. The results of the assessment showed two main crucial issues that could play a pivotal role in the achievement of Circular Economy action plan targets: the need to increase the recycling quotas for specific MSW fractions through the separate collection, and therefore the improvement of definite treatment process chains; the optimization of the recovery of secondary raw materials from incineration bottom ash, involving the Recycling of ferrous and nonferrous metals and the mineral fraction. Both issues need to find an extensive application across all member states to decrease the actual differences in the adoption of sustainable MSW management options.
KW - Bottom ash
KW - Circular economy
KW - Waste treatment
KW - Recycling
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520285
DO - https://doi.org/10.3390/en13236412
SN - 1996-1073
VL - 13
IS - 23
SP - 6412
EP - 6412
PB - MDPI
CY - Basel
AN - OPUS4-52028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gleim, Tobias
A1 - Chen, Hefeng
T1 - Numerical Analysis for an Electro‐Magneto‐Mechanical Phenomenon with High‐Order Accurate Methods
N2 - This paper establishes an axisymmetric model for a levitation device. Therein, the Maxwell equations are combined with the balance of linear momentum. Different possible formulations to describe the MAXWELL equations are presented and compared and discussed in the example. A high order finite element discretization using GALERKIN's method in space and the generalized NEWMARK‐α method in time are developed for the electro‐magneto‐mechanical approach. Several studies on spatial and temporal discretization with respect to convergence will be investigated. In addition, the boundary influences and the domain size with respect to the levitation device are also examined.
T2 - International Association for Applied Mathematics and Mechanics
CY - Kassel, Germany
DA - 16.03.2020
KW - High-Order Methods
KW - Electro-Magneto-Mechanical
KW - Levitation Device
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520720
DO - https://doi.org/10.1002/pamm.202000018
VL - 20
IS - 1
SP - e202000018
PB - Wiley‐VCH GmbH
CY - Online
AN - OPUS4-52072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bell, A. M.
A1 - von der Au, Marcus
A1 - Regnery, J.
A1 - Schmid, M.
A1 - Meermann, Björn
A1 - Reifferscheid, G.
A1 - Ternes, T.
A1 - Buchinger, S.
T1 - Does galvanic cathodic protection by aluminum anodes impact marine organisms?
N2 - Background: Cathodic protection by sacrifcial anodes composed of aluminum-zinc-indium alloys is often applied to protect ofshore support structures of wind turbines from corrosion. Given the considerable growth of renewable energies and thus ofshore wind farms in Germany over the last decade, increasing levels of aluminum, Indium and zinc are released to the marine environment. Although these metals are ecotoxicologically well-studied, data regarding their impact on marine organisms, especially sediment-dwelling species, as well as possible ecotoxicological efects of galvanic anodes are scarce. To investigate possible ecotoxicological efects to the marine environment, the diatom Phaedactylum tricornutum, the bacterium Aliivibrio fscheri and the amphipod Corophium volutator were exposed to dissolved galvanic anodes and solutions of aluminum and zinc, respectively, in standardized laboratory tests using natural seawater. In addition to acute toxicological efects, the uptake of these elements by C. volutator was investigated.
Results: The investigated anode material caused no acute toxicity to the tested bacteria and only weak but signifcant efects on algal growth. In case of the amphipods, the single elements Al and Zn showed signifcant efects only at the highest tested concentrations. Moreover, an accumulation of Al and In was observed in the crustacea species.
Conclusions: Overall, the fndings of this study indicated no direct environmental impact on the tested marine organisms by the use of galvanic anodes for cathodic protection. However, the accumulation of metals in, e.g., crustaceans might enhance their trophic transfer within the marine food web.
KW - Galvanic anodes
KW - Metal toxicity
KW - Metal uptake
KW - Corophium volutator
KW - Seawater
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520769
DO - https://doi.org/10.1186/s12302-020-00441-3
VL - 32
IS - 1
SP - Article number 157
AN - OPUS4-52076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wittmar, J.
A1 - Ohle, Corina
A1 - Kunte, Hans-Jörg
A1 - Brand, I.
T1 - Effect of Ectoine on the Conformation and Hybridization of dsDNA in Monolayer Films: A Spectroelectrochemical Study
N2 - Lack of long-time stability of dsDNA-based supramolecular assemblies is an important issue that hinders their applications. In this work, 20 base pairs long dsDNA fragments [(dCdG)20
65%] composed of 65% dCdG and 35% dAdT nucleotides were tethered via a thiol to the surface of a gold electrode. The selfassembled (dCdG)20
-65% monolayer was immersed in solutions
containing ectoine, a compatible solute. Electrochemical results showed that these monolayers were stable for one month. In situ IR spectroscopy indicated that ectoine interacts weakly with the phosphate-ribose backbone, dehydrating the phosphate groups and stabilizing the A-DNA conformation. This structural reorganization led to a reorientation of nucleic acid base pairs and a local disruption of the double-helix structure. However, the conformation and orientation of the dsDNA fragment was stable in the
KW - Ectoine
KW - dsDAN monolayer
KW - A-DNA conformation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533346
DO - https://doi.org/10.1002/celc.202100816
SN - 2196-0216
VL - 8
IS - 20
SP - 3844
EP - 3854
PB - Wiley-VCH GmbH
AN - OPUS4-53334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seher, Julia
A1 - Fröba, M.
T1 - Shape matters: The effect of particle morphology on the fast-charging performance of LiFePO4/C nanoparticle composite electrodes
N2 - For the successful use of lithium-ion batteries in automotive applications, reliable availability of high storage capacity and very short recharging times are essential. In order to develop the perfect battery for a certain application, structure–property relationships of each active material must be fully understood. LiFePO4 is of great interest due to its fast-charging capability and high stability regarding its thermal resistance and chemical reactivity. The anisotropic lithium-ion diffusion through the LiFePO4 crystal structure indicates a strong dependence of the electrochemical performance of a nanostructured active material on particle morphology. In this paper, the relationship of the particle morphology and fast-charging capability of LiFePO4/C core/shell nanoparticles in half-cells was studied. For this purpose, a new multistep synthesis strategy was developed. It involves the combination of a solvothermal synthesis followed by an in situ polymer coating and thermal calcination step. Monodisperse rodlike LiFePO4 nanoparticles with comparable elongation along the b-axis (30–50 nm) and a varying aspect ratio c/a (2.4–6.9) were obtained. A strong correlation of the fast-charging capability with the aspect ratio c/a was observed. When using LiFePO4 nanoparticles with the smallest aspect ratio c/a, the best electrochemical performance was received regarding the specific capacity at high C-rates and the cycling stability. A reduction of the aspect ratio c/a by 30% (3.6 to 2.4) was found to enhance the charge capacity at 10 C up to an order of magnitude (7.4–73 mA h·g–1).
KW - LiFePO4
KW - Schnellladung
KW - Nanoparticles
KW - Carbon
KW - Chemical synthesis
KW - Electrochemical cells
KW - Materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533004
DO - https://doi.org/10.1021/acsomega.1c03432
SN - 2470-1343
VL - 6
IS - 37
SP - 24062
EP - 24069
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-53300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maisels, A.
A1 - Hiller, A.
A1 - Simon, Franz-Georg
T1 - Chemisches Recycling für Kunststoffe: Status und Perspektiven
N2 - Das mechanische Recycling von Kunststoffen ist seit Jahren großtechnisch etabliert, hat aber technische und ökonomische Grenzen. Durch Verfahren des chemischen Recyclings gelangt man zurück zu Monomeren oder den Rohstoffen, so dass am Ende wieder Neuware für alle Einsatzgebiete von Kunststoffen entsteht. Die Vielfalt von chemischen Recyclingverfahren ist groß. Die Kapazitäten der Anlagen sind heute noch gering und die Wirtschaftlichkeit wird stark vom Ölpreis beeinflusst.
Die Rentabilitätsgrenze liegt derzeit bei einem Preis zwischen 50 und 60 US-$ pro Barrel.
KW - Chemisches Recycling
KW - Oxyfuel-Verbrennung
KW - Pyrolyse
KW - Solvolyse
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535952
DO - https://doi.org/10.1002/cite.202100115
SN - 0009-286X
SN - 1522-2640
VL - 93
IS - 11
SP - 1742
EP - 1750
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-53595
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Wolfgang
A1 - Senoner, M.
A1 - Stockmann, Jörg Manfred
A1 - Fernandez, V.
A1 - Fairley, N.
A1 - Passiu, C.
A1 - Spencer, N. D.
A1 - Rossi, A.
T1 - Summary of ISO/TC 201 International Standard ISO 18516:2019 Surface chemical analysis - Determination of lateral resolution and sharpness in beam-based methods with a range from nanometres to micrometres and its implementation for imaging laboratory X-ray photoelectron spectrometers (XPS)
N2 - ISO 18516:2019 Surface chemical analysis—Determination of lateral resolution and sharpness in beam-based methods with a range from nanometres to micrometres revises ISO 18516:2006 Surface chemical analysis—Auger electron spectroscopy and X-ray photoelectron spectroscopy—Determination of lateral resolution. It implements three different methods delivering parameters useful to express the lateral resolution: (1) the straight edge method, (2) the narrow line method and (3) the grating method. The theoretical background of these methods is introduced in ISO/TR 19319:2013 Surface chemical analysis—Fundamental approaches to determination of lateral resolution and sharpness in beam-based methods. The revised International Standard ISO 18516 delivers standardized procedures for the determination of the (1) effective lateral resolution by imaging of square-wave gratings, the (2) lateral resolution expressed as the parameter D12–88 characterizing the steepness of the sigmoidal edge spread function (ESF) determined by imaging a straight edge and (3) the lateral resolution expressed as the full width of half maximum of the line spread function (LSF), wLSF, determined by imaging a narrow line. The last method also delivers information on the shape of the LSF, which characterizes an individual imaging instrument. Finally, the implementation of all three standardized methods in the field of imaging laboratory X-ray photoelectron spectroscopy (XPS) is shortly presented. This part of the letter is based on the use of a new test sample developed at ETH Zurich, Switzerland. This test sample displays a micrometre scaled pattern motivated by the resolving power of recent imaging XPS instruments.
KW - Grating method
KW - Imaging AES
KW - Imaging SIMS
KW - Imaging XPS
KW - Lateral resolution
KW - Narrow line method
KW - Noise in image
KW - Resolution criterion
KW - Straight edge method
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536330
DO - https://doi.org/10.1002/sia.7025
SN - 1096-9918
VL - 54
IS - 4
SP - 320
EP - 327
PB - Wiley
CY - Chichester
AN - OPUS4-53633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Even, Morgane
A1 - Wilke, Olaf
A1 - Kalus, Sabine
A1 - Schultes, P.
A1 - Hutzler, C.
A1 - Luch, A.
T1 - Formaldehyde emissions from wooden toys: Comparison of different measurement methods and assessment of exposure
N2 - Formaldehyde is considered as carcinogenic and is emitted from particleboards and plywood used in toy manufacturing. Currently, the flask method is frequently used in Europe for market surveillance purposes to assess formaldehyde release from toys, but its concordance to Levels measured in emission test chambers is poor. Surveillance laboratories are unable to afford laborious and expensive emission chamber testing to comply with a new amendment of the European Toy Directive; they need an alternative method that can provide reliable results. Therefore, the application of miniaturised emission test chambers was tested. Comparisons between a 1 m3 emission test chamber and 44 mL microchambers with two particleboards over 28 days and between a 24 L desiccator chamber and the microchambers with three puzzle samples over 10 days resulted in a correlation coefficient r2 of 0.834 for formaldehyde at steady state. The correlation between the results obtained in microchambers vs. flask showed a high variability over 10 samples (r2: 0.145),
thereby demonstrating the error-proneness of the flask method in comparison to methods carried out under ambient parameters. An exposure assessment was also performed for three toy puzzles: indoor formaldehyde concentrations caused by puzzles were not negligible (up to 8 µg/m3), especially when more conservative exposure scenarios were considered.
KW - EN 717-3
KW - Formaldehyde
KW - Wooden toys
KW - Emission test chamber
KW - Flask method
KW - Microchamber
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520196
DO - https://doi.org/10.3390/ma14020262
VL - 14
IS - 2 (Special issue: Measurement of the environmental impact of materials)
SP - 262-1
EP - 262-16
PB - MDPI
AN - OPUS4-52019
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Solovyev, N.
A1 - El-Khatib, Ahmed
A1 - Costas-Rodrigues, M.
A1 - Schwab, K.
A1 - Griffin, E.
A1 - Raab, A.
A1 - Platt, B.
A1 - Theuring, F.
A1 - Vogl, Jochen
A1 - Vanhaecke, F.
T1 - Cu, Fe and Zn isotope ratios in murine Alzheimer's disease models suggest specific signatures of amyloidogenesis and tauopathy
N2 - Alzheimer’s disease (AD) is characterized by accumulation of tau and amyloid-beta in the brain, and recent evidence suggests a correlation between associated protein aggregates and trace elements, such as copper, iron and zinc. In AD, distorted brain redox homeostasis and complexation by amyloid-beta and hyperphosphorylated tau May alter the isotopic composition of essential mineral elements. Therefore, high-precision isotopic analysis may reveal changes in the homeostasis of these elements. We used inductively coupled plasma-mass spectrometry (ICP-MS)-based techniques to determine the total Cu, Fe and Zn contents in the brain, as well as their isotopic compositions in both mouse brain and serum.
Results for male transgenic tau (Line 66, L66) and amyloid/presenilin (5xFAD) mice were compared to those for the corresponding age- and gendermatched wild-type control mice (WT). Our data show that L66 brains showed significantly higher Fe levels than the corresponding WT. Significantly less Cu, but more Zn was found in 5xFAD brains. We observed significantly lighter isotopic compositions of Fe (enrichment in the lighter isotopes) in the brain, and in serum of L66 mice compared to WT. For 5xFAD mice, Zn exhibited a trend towards a lighter isotopic composition in brain and a heavier isotopic composition in serum compared to WT. Neither mouse model yielded differences in the isotopic composition of Cu. Our findings indicate significant pathology-specific alterations of Fe and Zn brain homeostasis in mouse models of AD. The associated changes in isotopic composition May serve as a marker for proteinopathies Underlying AD and other types of dementia.
KW - Alzheimer’s disease
KW - Tau
KW - Amyloid-beta
KW - Copper
KW - Iron
KW - Zinc
KW - Multi-collector inductively coupled plasma-mass spectrometry (ICP-MS)
KW - Brain
KW - Serum
KW - Isotopic analysis
KW - Total element determination
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520214
DO - https://doi.org/10.1016/j.jbc.2021.100292
VL - 296
SP - 100292
PB - Elsevier Inc.
CY - Amsterdam
AN - OPUS4-52021
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pienkoß, Fabian
A1 - Abis, M.
A1 - Bruno, M.
A1 - Grönholm, R.
A1 - Hoppe, M.
A1 - Kuchta, K.
A1 - Fiore, S.
A1 - Simon, Franz-Georg
T1 - Heavy metal recovery from the fine fraction of solid waste incineration bottom ash by wet density separation
N2 - This work is aimed at exploring the recovery of heavy metals from the fine fraction of solid waste incineration bottom ash.
For this study, wet-discharged bottom ash fine-fraction samples from full-scale treatment plants in Germany and Sweden were analyzed. The potential for the recovery of heavy metal compounds was investigated through wet density-separation with a shaking table. The feed materials were processed without any pre-treatment and the optimum processing conditions were determined by means of design of experiments. Tilt angle and stroke frequency were identified as the most relevant parameters, and the optimum settings were − 7.5° and 266 rpm, respectively. The obtained balanced copper enrichments (and yields) were 4.4 (41%), 6.2 (28%) and 2.4 (23%). A maximum copper enrichment of 14.5 with 2% yield was achieved, providing a concentrate containing 35.9 wt.% relevant heavy metal elements. This included 26.3 wt.% iron, 4.3 wt.% zinc and 3.8 wt.% copper. In conclusion, density separation with shaking tables can recover heavy metals from bottom ash fine fractions. Medium levels of heavy metal enrichment (e.g., for Cu 2.7–4.4) and yield (Cu: 26–41%) can be reached simultaneously.
However, the separation performance also depends on the individual bottom ash sample.
KW - Bottom ash
KW - Density separation
KW - Circular economy
KW - Design of experiments
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538569
DO - https://doi.org/10.1007/s10163-021-01325-1
SN - 1438-4957
SN - 1611-8227
VL - 24
SP - 364
EP - 377
PB - Springer Nature
CY - Heidelberg
AN - OPUS4-53856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Ziegler, Mathias
T1 - Detection of surface breaking cracks using flying line laser thermography: A Canny-based algorithm
N2 - In this work, we introduce a new algorithm for effectual crack detection using flying line laser thermography, based on the well-known Canny approach. The algorithm transforms the input thermographic sequence into an edge map. Experimental measurements are performed on a metallic component that contains surface breaking cracks due to industrial use. The specimen is tested using flying line thermography at different scanning speeds and laser input powers. Results obtained with the proposed algorithm are additionally compared with a previously established algorithm for flying spot thermography. The proposed Canny-based algorithm can be used in automated systems for thermographic non-destructive testing.
T2 - Advanced Infrared Technology and Applications 2021
CY - Online meeting
DA - 26.10.2021
KW - Canny approach
KW - Flying line thermography
KW - Crack detection
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539628
DO - https://doi.org/10.3390/engproc2021008022
SN - 2673-4591
VL - 8
IS - 1
SP - 1
EP - 4
PB - MDPI
CY - Basel
AN - OPUS4-53962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serebrennikova, P.
A1 - Komarov, V.
A1 - Sukhikh, A.
A1 - Khranenko, S.
A1 - Zadesenetz, A.
A1 - Gromilov, S
A1 - Yusenko, Kirill
T1 - [NiEn3](MoO4)0.5(WO4)0.5 co-crystals as single-source precursors for ternary refractory Ni-Mo-W alloys
N2 - The co-crystallisation of [NiEn3](NO3)2 (En = ethylenediamine) with Na2MoO4 and Na2WO4 from a water solution results in the formation of [NiEn3](MoO4)0.5(WO4)0.5 co-crystals. According to the X-ray diffraction analysis of eight single crystals, the parameters of the hexagonal unit cell (space group P–31c, Z = 2) vary in the following intervals: a = 9.2332(3)–9.2566(6); c = 9.9512(12)–9.9753(7) Å with the Mo/W ratio changing from 0.513(3)/0.487(3) to 0.078(4)/0.895(9). The thermal decomposition of [NiEn3](MoO4)0.5(WO4)0.5 individual crystals obtained by co-crystallisation was performed in He and H2 atmospheres. The ex situ X-ray study of thermal decomposition products shows the formation of nanocrystalline refractory alloys and carbide composites containing ternary Ni–Mo–W phases. The formation of carbon–nitride phases at certain stages of heating up to 1000 °C were shown.
KW - Single source precursors
KW - Phase diagrams
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540123
DO - https://doi.org/10.3390/nano11123272
VL - 11
IS - 12
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-54012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lay, Vera
A1 - Buske, S.
A1 - Townend, J.
A1 - Kellett, R.
A1 - Savage, M.
A1 - Schmitt, D. R.
A1 - Constantinou, A.
A1 - Eccles, J. D.
A1 - Gorman, A.
A1 - Bertram, M.
A1 - Hall, K.
A1 - Lawton, D.
A1 - Kofman, R.
T1 - 3D Active Source Seismic Imaging of the Alpine Fault Zone and the Whataroa Glacial Valley in New Zealand
N2 - The Alpine Fault zone in New Zealand marks a major transpressional plate boundary that is late in its typical earthquake cycle. Understanding the subsurface structures is crucial to understand the tectonic processes taking place. A unique seismic survey including 2D lines, a 3D array, and borehole recordings, has been performed in the Whataroa Valley and provides new insights into the Alpine Fault zone down to ∼2 km depth at the location of the Deep Fault Drilling Project (DFDP)-2 drill site. Seismic images are obtained by focusing prestack depth migration approaches. Despite the challenging conditions for seismic imaging within a sediment filled glacial valley and steeply dipping valley flanks, several structures related to the valley itself as well as the tectonic fault system are imaged. A set of several reflectors dipping 40°–56° to the southeast are identified in a ∼600 m wide zone that is interpreted to be the minimum extent of the damage zone. Different approaches image one distinct reflector dipping at ∼40°, which is interpreted to be the main Alpine Fault reflector located only ∼100 m beneath the maximum drilled depth of the DFDP-2B borehole. At shallower depths (z < 0.5 km), additional reflectors are identified as fault segments with generally steeper dips up to 56°. Additionally, a glacially over-deepened trough with nearly horizontally layered sediments and a major fault (z < 0.5 km) are identified 0.5–1 km south of the DFDP-2B borehole. Thus, a complex structural environment is seismically imaged and shows the complexity of the Alpine Fault at Whataroa.
KW - Imaging
KW - Signal processing
KW - Seismic
KW - Borehole
KW - DAS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539163
DO - https://doi.org/10.1029/2021JB023013
VL - 126
IS - 12
SP - 1
EP - 21
PB - American Geophysical Union
AN - OPUS4-53916
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dorgerloh, Ute
A1 - Becker, Roland
A1 - Riedel, Juliane
A1 - Hofmann, Andrea
T1 - Comparison of gas- and liquid chromatography-mass spectrometry for trace analysis of anilines in groundwater
N2 - Three chromatographic procedures were investigated regarding their potential for the quantification of aniline and 19 of its methylated and chlorinated derivatives in groundwater. These methods were based on liquid-liquid-extraction in combination with gas chromatography and single quadrupole mass spectrometry (GC/MS) according to German standard DIN 38407-16:1999 and its extension using tandem mass spectrometry (GC/MS-MS), both following liquid-liquid extraction, and as third alternative the direct injection of the water sample into a liquid chromatograph coupled to tandem mass spectrometry (LC/MS-MS). Results were compared using fortified water and real-world contaminated groundwater used in an interlaboratory comparison. It could be shown that GC/MS and GC/MS-MS yielded results deviating less than 10% from each other while all three procedure displayed quantification results deviating less than 15% from the intercomparison reference values in case of each analyte in the concentration range between 1 and 45 µg L-1. Though GC/MS-MS displays a ten-fold higher sensitivity than single quadrupole GC/MS, the precision of both methods in the concentration range was similar. LC/MS-MS has the advantage of no further sample preparation due to the direct injection and leads for methylanilines and meta-, para- substituted chloroanilines to results sufficiently equivalent to the standardised GC/MS method. However, LC/MS-MS is not suitable for ortho-chloroaniline derivates due to significantly lower ion yields than meta- and para-substituted chloroanilines.
KW - Interlaboratory comparison
KW - Aniline
KW - Chloroanilines
KW - Methylanilines
KW - Groundwater
KW - GC/MS
KW - GC/MS-MS
KW - LC/MS-MS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535793
DO - https://doi.org/10.1080/03067319.2021.1987423
VL - 103
IS - 19
SP - 8465
EP - 8477
PB - Taylor & Francis
CY - London
AN - OPUS4-53579
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, D.
A1 - Bertovic, Marija
A1 - Dethof, F.
A1 - Heckel, Thomas
A1 - Jüngert, A.
A1 - Keßler, S.
A1 - Rentala, V.
A1 - Rosenthal, Martina
A1 - Stolz, R.
A1 - Vrana, J.
T1 - Die deutschen Bestrebungen zur Normierung der Fähigkeits- und Zuverlässigkeitsbewertung der zerstörungsfreien Prüfung
N2 - Seit 1999 existiert das MIL-HDBK 1823, die us-amerikanische Leitfaden zur Erstellung einer Probability of Detection (POD; Fehlerdetektionswahrscheinlichkeit). Obwohl das Dokument als internationaler Stand der Technik angesehen wird, ist die allgemeine Anwendung in der ZfP-Praxis von einigen Nachteilen begleitet:
1. Die beschriebenen POD‘s bilden ausschließlich die Grundlagen-POD ab, jeweils mit nur einem Fehlerparameter und einem Signalparameter. Modernere Ansätze werden hier nicht adressiert.
2. Die aktuelle Version verzichtet fast vollständig auf konkrete mathematische Formulierungen.
3. Die Richtlinie richtet sich hauptsächlich an die militärische Luftfahrt.
4. Das Dokument ist nur in englischer Sprache verfügbar.
Mit Hilfe eines BMWi-Förderprojekts wird ein weiterführendes Regelwerk auf Basis der MIL-HDBK 1823 unter deutscher Federführung erarbeitet, welches die Anwendung der POD-Berechnung auf eine breitere Basis stellt und die oben genannten Nachteile der MIL-HDBK 1823 behebt.
Das vorgestellte Projekt „normPOD“ wird eine normative, branchenübergreifend einsetzbare Beschreibung des Vorgehens bei der Berechnung einer POD zur Zuverlässigkeitsbewertung zerstörungsfreier Prüfungen entwickeln. Hierbei wird Klarheit über unterschiedliche POD-Ansätze geschaffen und anhand praktischer Beispiele aus Maschinenbau und Bauwesen ein Leitfaden für den Praxiseinsatz erarbeitet.
Das Poster gibt einen Überblick über die geplanten Arbeiten innerhalb des Projekts und lädt die Beteiligten der DGZfP-Jahrestagung zur Diskussion ein, um eine breite Basis und Akzeptanz für die entwickelten Berechnungsverfahren zu schaffen, insbesondere in Hinblick auf ZfP 4.0 und Digitalisierung.
T2 - Jahrestagung der DGZfP
CY - Online meeting
DA - 10.05.2021
KW - Zerstörungsfreie Prüfung
KW - ZfP
KW - Zuverlässigkeit
KW - Standardisierung
KW - Human Factors
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535628
UR - www.ndt.net/article/dgzfp2021/papers/P40.pdf
SP - 1
EP - 8
AN - OPUS4-53562
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Griesche, Axel
A1 - Pfretzschner, B.
A1 - Taparli, Ugur Alp
A1 - Kardjilov, N.
T1 - Time-Resolved Neutron Bragg-Edge Imaging: A Case Study by Observing Martensitic Phase Formation in Low Temperature Transformation (LTT) Steel during GTAW
N2 - Polychromatic and wavelength-selective neutron transmission radiography were applied during bead-on-plate welding on 5 mm thick sheets on the face side of martensitic low transformation temperature (LTT) steel plates using gas tungsten arc welding (GTAW). The in situ visualization of austenitization upon welding and subsequent α’-martensite formation during cooling could be achieved with a temporal resolution of 2 s for monochromatic imaging using a single neutron wavelength and of 0.5 s for polychromatic imaging using the full spectrum of the beam (white beam). The spatial resolution achieved in the experiments was approximately 200 µm. The transmitted monochromatic neutron beam intensity at a wavelength of λ = 0.395 nm was significantly reduced during cooling below the martensitic start temperature Ms since the emerging martensitic phase has a ~10% higher attenuation coefficient than the austenitic phase. Neutron imaging was significantly influenced by coherent neutron scattering caused by the thermal motion of the crystal lattice (Debye–Waller factor), resulting in a reduction in the neutron transmission by approx. 15% for monochromatic and by approx. 4% for polychromatic imaging.
KW - Austenite-to-martensite transformation
KW - Neutron radiography
KW - Bragg-edge imaging
KW - Gas tungsten arc welding (GTAW)
KW - Debye–Waller factor
KW - Low transformation temperature (LTT) steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538016
DO - https://doi.org/10.3390/app112210886
VL - 11
IS - 22
SP - 10886
PB - MDPI
CY - Basel
AN - OPUS4-53801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolzenberg, U.
A1 - Schmitt Rahner, M.
A1 - Pullner, B.
A1 - Legall, Herbert
A1 - Bonse, Jörn
A1 - Kluge, M.
A1 - Ortner, A.
A1 - Hoppe, B.
A1 - Krüger, Jörg
T1 - X-ray emission hazards from ultrashort pulsed laser material processing in an industrial setting
N2 - Interactions between ultrashort laser pulses with intensities larger than 10^13 W/cm^2 and solids during material processing can lead to the emission of X-rays with photon energies above 5 keV, causing radiation hazards to operators. A framework for inspecting X-ray emission hazards during laser material processing has yet to be developed. One requirement for conducting radiation protection inspections is using a reference scenario, i.e., laser settings and process parameters that will lead to an almost constant and high level of X-ray emissions. To study the feasibility of setting up a reference scenario in practice, ambient dose rates and photon energies were measured using traceable measurement equipment in an industrial setting at SCHOTT AG. Ultrashort pulsed (USP) lasers with a maximum average power of 220 W provided the opportunity to measure X-ray emissions at laser peak intensities of up to 3.3 × 10^15 W/cm^2 at pulse durations of ~1 ps. The results indicate that increasing the laser peak intensity is insufficient to generate high dose rates. The investigations were affected by various constraints which prevented measuring high ambient dose rates. In this work, a list of issues which may be encountered when performing measurements at USP-laser machines in industrial settings is identified.
KW - X-ray emission hazards
KW - Ultrashort pulsed laser
KW - Radiation protection
KW - Industrial applications
KW - Protection housing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538632
DO - https://doi.org/10.3390/ma14237163
SN - 1996-1944
VL - 14
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-53863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biedermann, P. H. W.
A1 - Rohlfs, M.
A1 - McMahon, Dino Peter
A1 - Meunier, J.
T1 - Editorial: Microbial drivers of sociality – From multicellularity to animal societies
N2 - While sociality is present in a taxonomically diverse number of species, most animals remain solitary (Bourke, 2011). Over the last centuries, this apparent imbalance in social and non-social animals has led to a great deal of research aimed at shedding light on the biotic and abiotic factors explaining the emergence and maintenance of sociality in nature (West et al., 2015).
Among them, microbes were quickly identified as a major problem for the evolution of social life, because frequent contact between group members typically facilitates the transmission of pathogens, high nest fidelity favours the establishment of microbial pathogens close to their social hosts and, finally, because social groups often exhibit limited genetic diversity and thus limited genetic resistance against certain pathogen strains (Schmid-Hempel, 1998; Cremer et al., 2007). However, this long-standing view has changed considerably over the last few years. Recent research indeed revealed that group living may be more effective than solitary living to Limit the risk of infection by pathogenic microbes because group living also allows the development of an additional layer of defence against pathogens in the form of social immunity (Cremer et al., 2007; Cotter and Kilner, 2010). Under strong pressure from pathogens, microbes could therefore promote, rather than hinder, the evolutionary transition from solitary to group Living (Meunier, 2015; Biedermann and Rohlfs, 2017). Moreover, we are increasingly aware that many microbes provide essential benefits to their hosts by performing critical digestive, physiological, and reproductive functions (Engel and Moran, 2013; McFall-Ngai et al., 2013). The need to Access beneficial microbes may thus have played a role in the expression of frequent and tight interactions between conspecifics and ultimately promoted social evolution (Wilson, 1971; Onchuru et al., 2018). Finally, a growing number of studies suggest that microbes could enforce the Aggregation and expression of cooperative behaviours of the hosts to increase their chance of reaching new hosts and may therefore be involved in the evolution of host sociality (Lewin-Epstein et al., 2017) (but see Johnson and Foster, 2018).
KW - Microbe
KW - Sociality
KW - Multicellularity
KW - Evolution
KW - Symbiosis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538741
DO - https://doi.org/10.3389/fevo.2021.752906
SN - 2296-701X
VL - 9
SP - 1
EP - 4
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-53874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roesch, Philipp
A1 - Vogel, Christian
A1 - Huthwelker, T.
A1 - Wittwer, Philipp
A1 - Simon, Franz-Georg
T1 - Investigation of per‑ and polyfluoroalkyl substances (PFAS) in soils and sewage sludges by fluorine K‑edge XANES spectroscopy and combustion ion chromatography
N2 - For the first time, fluorine K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to detect per- and polyfluoroalkyl substances (PFAS) in various soil and sewage sludge samples. The method can be used to determine the speciation of inorganic and organic fluorides, without pre-treatment of solid samples. Therefore, XANES spectra of several inorganic fluorides as well as selected fluorinated organic compounds were recorded. While inorganic fluorides partially exhibit a variety of sharp spectral features in the XANES spectrum, almost all inspected organofluorine compounds show two distinct broad features at 688.5 and 692.0 eV. Moreover, the peak intensity ratio 688.5 eV/692.0 eV in the PFAS XANES spectrum can be inversely correlated to the chain length of the perfluoro sulfonic acid group. The detection of targeted PFAS by bulk-XANES spectroscopy in combination with linear combination fitting in soils and sewage sludges was not applicable due to the low organic fluorine to total fluorine ratio of the samples (0.01–1.84%). Nonetheless, direct analysis of pure PFAS revealed that analysis of organofluorine species might be achieved in higher concentrated samples. Furthermore, quantitative measurements by combustion ion chromatography (CIC) evaluated as sum parameters extractable organically bound fluorine (EOF) and total fluorine (TF) emphasize that besides soils, sewage sludges are a significant source of organic fluorine in agriculture (154–7209 μg/kg).
KW - Sewage sludge
KW - Combustion ion chromatography
KW - Oil
KW - X-ray absorption near-edge structure (XANES) spectroscopy
KW - Per- and polyfluoroalkyl substances (PFAS)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538953
DO - https://doi.org/10.1007/s11356-021-17838-z
VL - 29
IS - 18
SP - 26889
EP - 26899
PB - Springer
AN - OPUS4-53895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - He, Shulin
A1 - Sieksmeyer, Thorben
A1 - Che, Y.
A1 - Mora, M. A. E.
A1 - Stiblik, P.
A1 - Banasiak, Ronald
A1 - Harrison, M. C.
A1 - Sobotnik, J.
A1 - Wang, Z.
A1 - Johnston, P. R.
A1 - McMahon, Dino Peter
T1 - Evidence for reduced immune gene diversity and activity during the evolution of termites
N2 - The evolution of biological complexity is associated with the emergence of bespoke immune systems that maintain and protect organism integrity. Unlike the well-studied immune systems of cells and individuals, little is known about the origins of immunity during the transition to eusociality, a major evolutionary transition comparable to the evolution of multicellular organisms from single-celled ancestors. We aimed to tackle this by characterizing the immune gene repertoire of 18 cockroach and termite species, spanning the spectrum of solitary, subsocial and eusocial lifestyles. We find that key transitions in termite sociality are correlated with immune gene family contractions. In cross-species comparisons of immune gene expression, we find evidence for a caste-specific social defence system in termites, which appears to operate at the expense of individual immune protection. Our study indicates that a major transition in organismal complexity may have entailed a fundamental reshaping of the immune system optimized for group over individual defence.
KW - Social insect
KW - Subsocial
KW - Cockroach
KW - Major transition
KW - Contraction
KW - Expansion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538878
DO - https://doi.org/10.1098/rspb.2020.3168
SN - 0962-8452
SN - 1471-2954
VL - 288
IS - 1945
SP - 1
EP - 10
PB - The Royal Society
CY - London
AN - OPUS4-53887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raysyan, Anna
A1 - Schneider, Rudolf
T1 - Development of a Lateral Flow Immunoassay (LFIA) to Screen for the Release of the Endocrine Disruptor Bisphenol A from Polymer Materials and Products
N2 - One of the most important chemicals used in the production of polymer plastics and coatings is bisphenol A. However, despite the large number of studies on the toxicity and hormonal activity of BPA, there are still open questions and thus considerable media attention regarding BPA toxicity. Hence, it is necessary to develop a sensitive, simple, cost-efficient, specific, portable, and rapid method for monitoring bisphenol A and for high sample throughput and on-site screening analysis. Lateral flow immunoassays have potential as rapid tests for on-site screening. To meet sensitivity criteria, they must be carefully optimized. A latex microparticle-based LFIA for detection of BPA was developed. The sensitivity of the assay was improved by non-contact printing of spot grids as the control and test lines with careful parameter optimization. Results of the test could be visually evaluated within 10 min with a visual cut-off of 10 µg/L (vLOD). Alternatively, photographs were taken, and image analysis performed to set up a calibration, which allowed for a calculated limit of detection (cLOD) of 0.14 µg/L. The method was validated for thermal paper samples against ELISA and LC–MS/MS as reference methods, showing good agreement with both methods
KW - Endokrine Disruptoren
KW - Polymere
KW - Schnelltest
KW - Endocrine disruptor
KW - Bisphenol A
KW - LFIA
KW - Immunoassay
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540492
DO - https://doi.org/10.3390/bios11070231
VL - 11
IS - 7
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-54049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Van Den Bossche, T.
A1 - Kunath, B.
A1 - Schallert, K.
A1 - Schäpe, S.
A1 - Abraham, P. E.
A1 - Armengaud, J.
A1 - Arntzen, M. Ø.
A1 - Bassignani, A.
A1 - Benndorf, D.
A1 - Fuchs, S.
A1 - Giannone, R. J.
A1 - Griffin, T. J.
A1 - Hagen, L. H.
A1 - Halder, R.
A1 - Henry, C.
A1 - Hettich, R. L.
A1 - Heyer, R.
A1 - Jagtap, P.
A1 - Jehmlich, N.
A1 - Jensen, M.
A1 - Juste, C.
A1 - Kleiner, M.
A1 - Langella, O.
A1 - Lehmann, T.
A1 - Leith, E.
A1 - May, P.
A1 - Mesuere, B.
A1 - Miotello, G.
A1 - Peters, S. L.
A1 - Pible, O.
A1 - Queiros, P. T.
A1 - Reichl, U.
A1 - Renard, B. Y.
A1 - Schiebenhoefer, H.
A1 - Sczyrba, A.
A1 - Tanca, A.
A1 - Trappe, K.
A1 - Trezzi, J.-P.
A1 - Uzzau, S.
A1 - Verschaffelt, P.
A1 - von Bergen, M.
A1 - Wilmes, P.
A1 - Wolf, M.
A1 - Martens, L.
A1 - Muth, Thilo
T1 - Critical Assessment of MetaProteome Investigation (CAMPI): A multi-laboratory comparison of established workflows
N2 - Metaproteomics has matured into a powerful tool to assess functional interactions in microbial communities. While many metaproteomic workflows are available, the impact of method choice on results remains unclear. Here, we carry out a community-driven, multi-laboratory comparison in metaproteomics: the critical assessment of metaproteome investigation study (CAMPI). Based on well-established workflows, we evaluate the effect of sample preparation, mass spectrometry, and bioinformatic analysis using two samples: a simplified, laboratory-assembled human intestinal model and a human fecal sample. We observe that variability at the peptide level is predominantly due to sample processing workflows, with a smaller contribution of bioinformatic pipelines. These peptide-level differences largely disappear at the protein group level. While differences are observed for predicted community composition, similar functional profiles are obtained across workflows. CAMPI demonstrates the robustness of present-day metaproteomics research, serves as a template for multi-laboratory studies in metaproteomics, and provides publicly available data sets for benchmarking future developments.
KW - Metaproteomics
KW - Mass spectrometry
KW - Data science
KW - Benchmarking
KW - Bioinformatics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541220
DO - https://doi.org/10.1038/s41467-021-27542-8
SN - 2041-1723
VL - 12
SP - 1
EP - 15
PB - Nature Publishing Group
CY - London
AN - OPUS4-54122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Winkelmann, A.
T1 - About the reliability of EBSD measurements: Data enhancement
N2 - An extensive set of information about the diffracting volume is carried by EBSD patterns: the crystal lattice, the reciprocal lattice, the crystal structure, the crystal symmetry, the mean periodic number of the diffracting phase, the source point from where it has been projected (projection centre), the crystal orientation, the sample topography (local tilt), the (preparation) quality of defect density of the crystal, and possible pattern overlaps. Some of this information is used regularly in conventional EBSD analyses software while others are still waiting for a more widespread application. Despite the wealth of information available, the accuracy and precision of the data that are presently extracted from conventional EBSD patterns are often well below the actual physical limits. Using a selection of example applications, we will demonstrate the gain in angular resolution possible using relatively low-resolution patterns of approximately 20k pixels in combination with pattern matching (PM) approaches. In this way, fine details in a microstructure can be revealed which would otherwise be hidden in the orientation noise.
KW - EBSD
KW - Orientation precision
KW - Disorientation
KW - Grain boundary
KW - Phase transformation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521618
DO - https://doi.org/10.1088/1757-899X/891/1/012018
VL - 891
SP - 012018
PB - IOP Science
AN - OPUS4-52161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herrmann, K.
A1 - Pech May, Nelson Wilbur
A1 - Retsch, M.
T1 - Photoacoustic thermal characterization of low thermal diffusivity thin films
N2 - The photoacoustic measurement technique is a powerful yet underrepresented method to characterize the thermal transport properties of thin films. For the case of isotropic low thermal diffusivity samples, such as glasses or polymers, we demonstrate a general approach to extract the thermal conductivity with a high degree of significance. We discuss in particular the influence of thermal effusivity, thermal diffusivity, and sample layer thickness on the significance and accuracy of this measurement technique. These fundamental thermal properties guide sample and substrate selection to allow for a feasible thermal transport characterization. Furthermore, our data evaluation allows us to directly extract the thermal conductivity from this transient technique, without separate determination of the volumetric heat capacity, when appropriate boundary conditions are fulfilled.
Using silica, poly(methyl methacrylate) (PMMA) thin films, and various substrates (quartz, steel, and silicon), we verify the quantitative correctness of our analytical approach.
KW - Thermal conductivity
KW - Photoacoustic characterization
KW - Thin film characterization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528743
DO - https://doi.org/10.1016/j.pacs.2021.100246
SN - 2213-5979
VL - 22
SP - 100246
PB - Elsevier
AN - OPUS4-52874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Faßbender, Sebastian
A1 - Rodiouchkina, K.
A1 - Vanhaecke, F.
A1 - Meermann, Björn
T1 - Correction to: Method development for on-line species-specific sulfur
N2 - This is a corrigendum to the original article "Method development for on-line species-specific sulfur isotopic analysis by means of capillary electrophoresis/multicollector ICP-mass spectrometry" that was published in the journal "Analytical and Bioanalytical Chemistry", vol. 412 (202), no. 23, pp. 5637-5646.
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528796
DO - https://doi.org/10.1007/s00216-021-03474-6
SP - 1
PB - Springer
CY - Berlin, Heidelberg
AN - OPUS4-52879
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Albarrán Martínez, M. J.
A1 - Ghigo, Tea
T1 - The practice of writing inside an Egyptian monastic settlement
N2 - Over the last few years, the Federal Institute for material research (BAM, Berlin) together with the Centre for the Study of Manuscript Cultures (CSMC, University of Hamburg) have initiated a systematic material investigation of black inks produced from Late Antiquity to the Middle Ages (ca. fourth century CE–fourteenth/fifteenth centuries CE), aimed primarily at extending and complementing findings from previous sporadic studies. Part of this systematic investigation has focused on Egyptian Coptic manuscripts, and the present preliminary study is one of its outputs. It centres on a corpus of 45 Coptic manuscripts—43 papyri and 2 ostraca—preserved at the Palau-Ribes and Roca-Puig collections in Barcelona. The manuscripts come from the Monastery of Apa Apollo at Bawit, one of the largest monastic settlements in Egypt between the Late Antiquity and the Early Islamic Period (sixth–eighth centuries CE). The composition of their black inks was investigated in situ using near-infrared reflectography (NIRR) and X-ray fluorescence (XRF). The analyses determined that the manuscripts were written using different types of ink: pure carbon ink; carbon ink containing iron; mixed inks containing carbon, polyphenols and metallic elements; and iron-gall ink. The variety of inks used for the documentary texts seems to reflect the articulate administrative system of the monastery of Bawit. This study reveals that, in contrast to the documents, written mostly with carbon-based inks, literary biblical texts were written with iron-gall ink. The frequent reuse of papyrus paper for certain categories of documents may suggest that carbon-based inks were used for ephemeral manuscripts, since they were easy to erase by abrasion.
KW - Papyrus
KW - Ink analysis
KW - Coptic manuscripts
KW - Bawit
KW - Mixed ink
KW - Near-infrared refectography
KW - X-ray fuorescence
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528833
DO - https://doi.org/10.1186/s40494-021-00541-0
SN - 2050-7445
VL - 9
IS - 1
SP - 1
EP - 15
PB - Springer Open
CY - Rome, Italy
AN - OPUS4-52883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kauss, Norman
A1 - Heyn, A.
A1 - Michael, O.
A1 - Schymura, M.
A1 - Rosemann, P.
T1 - Application limits and sensitisation behaviour of the manganese- and nitrogen-alloyed austenitic stainless steel P2000 (X13CrMnMoN18-14-3)
N2 - Nickel‐free high‐nitrogen‐alloyed stainless steels like the P2000 (X13CrMnMoN18‐14‐3) were developed to enhance the strength and corrosion resistance of austenitic stainless steels like 304 and 316 while keeping the typical high ductility. The mechanical and corrosive properties of P2000 were investigated and compared with 304 and 316 to highlight the application opportunities of this new alloy. The microstructure of the solution‐annealed condition was characterised by electron backscatter diffraction and the mechanical properties were studied by uniaxial tensile tests, Charpy impact tests and hardness measurements. The passivation behaviour was analysed using the electrochemical potentiodynamic reactivation, whereas the pitting corrosion resistance was compared by pitting potentials and pitting temperatures. However, secondary thermal influences or suboptimal heat treatment can impair the corrosion resistance due to the precipitation of secondary phases and the resulting sensitisation. Thermodynamic calculations and artificial ageing treatment in the range of 500–900°C for up to 100 h were used to determine critical time–temperature parameters for sensitisation. The microstructure of the various aged states was evaluated by scanning electron microscopy and compared with the degrading corrosion resistance characterised by the KorroPad method.
KW - Austenitic stainless steel
KW - Electrochemical methods
KW - High‐nitrogen steel
KW - Mechanical properties
KW - Corrosion resistance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527925
DO - https://doi.org/10.1002/maco.202112450
VL - 71
IS - 10
SP - 1656
EP - 1667
PB - Wiley-VCH GmbH
AN - OPUS4-52792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schulze-Makuch, D.
A1 - Lipus, D.
A1 - Arens, F. L.
A1 - Baque, M.
A1 - Bornemann, T. L. V.
A1 - de Vera, J. P.
A1 - Flury, M.
A1 - Froesler, J.
A1 - Heinz, J.
A1 - Hwang, Y.
A1 - Kounaves, S. P.
A1 - Mangelsdorf, K.
A1 - Meckenstock, R. U.
A1 - Pannekens, M.
A1 - Probst, A. J.
A1 - Saenz, J. S.
A1 - Schirmack, J.
A1 - Schloter, M.
A1 - Schmitt-Kopplin, P.
A1 - Schneider, Beate
A1 - Uhl, J.
A1 - Vestergaard, G.
A1 - Valenzuela, B.
A1 - Zamorano, P.
A1 - Wagner, D.
T1 - Microbial hotspots in lithic microhabitats inferred from DNA fractionation and metagenomics in the Atacama Desert
N2 - The existence of microbial activity hotspots in temperate regions of Earth is driven by soil heterogeneities, especially the temporal and spatial availability of nutrients. Here we investigate whether microbial activity hotspots also exist in lithic microhabitats in one of the most arid regions of the world, the Atacama Desert in Chile. While previous studies evaluated the total DNA fraction to elucidate the microbial communities, we here for the first time use a DNA separation approach on lithic microhabitats, together with metagenomics and other analysis methods (i.e., ATP, PLFA, and metabolite analysis) to specifically gain insights on the living and potentially active microbial community. Our results show that hypolith colonized rocks are microbial hotspots in the desert environment. In contrast, our data do not support such a conclusion for gypsum crust and salt rock environments, because only limited microbial activity could be observed. The hypolith community is dominated by phototrophs, mostly Cyanobacteria and Chloroflexi, at both study sites. The gypsum crusts are dominated by methylotrophs and heterotrophic phototrophs, mostly Chloroflexi, and the salt rocks (halite nodules) by phototrophic and halotolerant endoliths, mostly Cyanobacteria and Archaea. The major environmental constraints in the organic-poor arid and hyperarid Atacama Desert are water availability and UV irradiation, allowing phototrophs and other extremophiles to play a key role in desert ecology.
KW - Desert ecology
KW - Extremophile
KW - Hyperarid
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527959
DO - https://doi.org/10.3390/microorganisms9051038
SN - 2076-2607
VL - 9
IS - 5
SP - 1038
PB - MDPI
CY - Basel
AN - OPUS4-52795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abis, M.
A1 - Bruno, M.
A1 - Simon, Franz-Georg
A1 - Grönholm, R.
A1 - Hoppe, M.
A1 - Kuchta, K.
A1 - Fiore, S.
T1 - A Novel Dry Treatment for Municipal Solid Waste Incineration Bottom Ash for the Reduction of Salts and Potential Toxic Elements
N2 - The main obstacle to bottom ash (BA) being used as a recycling aggregate is the content of salts and potential toxic elements (PTEs), concentrated in a layer that coats BA particles. This work presents a dry treatment for the removal of salts and PTEs from BA particles. Two pilotscale abrasion units (with/without the removal of the fine particles) were fed with different BA samples. The performance of the abrasion tests was assessed through the analyses of particle size and moisture, and that of the column leaching tests at solid-to-liquid ratios between 0.3 and 4.
The results were: the particle-size distribution of the treated materials was homogeneous (25 wt % had dimensions <6.3 mm) and their moisture halved, as well as the electrical conductivity of the leachates. A significant decrease was observed in the leachates of the treated BA for sulphates (44%), chlorides (26%), and PTEs (53% Cr, 60% Cu and 8% Mo). The statistical analysis revealed good correlations between chloride and sulphate concentrations in the leachates with Ba, Cu, Mo, and Sr, illustrating the consistent behavior of the major and minor components of the layer surrounding BA particles. In conclusion, the tested process could be considered as promising for the improvement of BA valorization.
KW - Bottom ash
KW - Dry treatment
KW - Potential toxic elements
KW - Salts
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527963
DO - https://doi.org/10.3390/ma14113133
SN - 1996-1944
VL - 14
IS - 11
SP - 3133
PB - MDPI
CY - Basel
AN - OPUS4-52796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Mesnil, O.
A1 - Prager, Jens
A1 - Gohlke, Dirk
A1 - Boller, C.
T1 - Damage quantification in an aluminium-CFRP composite structure using guided wave wavenumber mapping: Comparison of instantaneous and local wavenumber analyses
N2 - Composite-overwrapped pressure vessels (COPV) are increasingly used in the transportation industry due to their high strength to mass ratio. Throughout the years, various designs were developed and found their applications. Currently, there are five designs, which can be subdivided into two main categories - with a load-sharing metal liner and with a non-load-sharing plastic liner. The main damage mechanism defining the lifetime of the first type is fatigue of the metal liner, whereas for the second type it is fatigue of the composite overwrap. Nevertheless, one damage type which may drastically reduce the lifetime of COPV is impact-induced damage. Therefore, this barely visible damage needs to be assessed in a non-destructive way to decide whether the pressure vessel can be further used or has to be put out of service. One of the possible methods is based on ultrasonic waves. In this contribution, both conventional ultrasonic testing (UT) by high-frequency bulk waves and wavenumber mapping by low frequency guided waves are used to evaluate impact damage. Wavenumber mapping techniques are first benchmarked on a simulated aluminium panel then applied to experimental measurements acquired on a delaminated aluminium-CFRP composite plate which corresponds to a structure of COPV with a load-sharing metal liner. The analysis of experimental data obtained from measurements of guided waves propagating in an aluminium-CFRP composite plate with impact-induced damage is performed. All approaches show similar performance in terms of quantification of damage size and depths while being applied to numerical data. The approaches used on the experimental data deliver an accurate estimate of the in-plane size of the large delamination at the aluminium-CFRP interface but only a rough estimate of its depth. Moreover, none of the wavenumber mapping techniques used in the study can quantify every delamination between CFRP plies caused by the impact, which is the case for conventional UT. This may be solved by using higher frequencies (shorter wavelengths) or more advanced signal processing techniques. All in all, it can be concluded that imaging of complex impact damage in fibre-reinforced composites based on wavenumber mapping is not straightforward and stays a challenging task.
KW - Ultrasonic guided waves
KW - Instantaneous wavenumber analysis
KW - Local wavenumber analysis
KW - Signal processing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528203
DO - https://doi.org/10.1016/j.ndteint.2021.102472
SN - 0963-8695
VL - 122
SP - 2472
PB - Elsevier Ltd.
CY - Amsterdam, Netherlands
AN - OPUS4-52820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tschöke, K.
A1 - Müller, I.
A1 - Memmolo, V.
A1 - Moix-Bonet, M.
A1 - Moll, J.
A1 - Lugovtsova, Yevgeniya
A1 - Golub, M.
A1 - Sridaran Venkat, R.
A1 - Schubert, L.
T1 - Feasibility of Model-Assisted Probability of Detection Principles for Structural Health Monitoring Systems based on Guided Waves for Fibre-Reinforced Composites
N2 - In many industrial sectors, Structural Health Monitoring (SHM) is considered as an addition to Non-Destructive Testing (NDT) that can reduce maintenance effort during lifetime of a technical facility, structural component or vehicle. A large number of SHM methods is based on ultrasonic waves, whose properties change depending on structural health. However, the wide application of SHM systems is limited due to the lack of suitable methods to assess their reliability. The evaluation of the system performance usually refers to the determination of the Probability of Detection (POD) of a test procedure. Up to now, only few limited methods exist to evaluate the POD of SHM systems, which prevent them from being standardised and widely accepted in industry. The biggest hurdle concerning the POD calculation is the large amount of samples needed. A POD analysis requires data from numerous identical structures with integrated SHM systems. Each structure is then damaged at different locations and with various degrees of severity. All of this is connected to high costs. Therefore, one possible way to tackle this problem is to perform computer-aided investigations. In this work, the POD assessment procedure established in NDT according to the Berens model is adapted to guided wave-based SHM systems. The approach implemented here is based on solely computer-aided investigations. After efficient modelling of wave propagation phenomena across an automotive component made of a carbon fibre-reinforced composite, the POD curves are extracted. Finally, the novel concept of a POD map is introduced to look into the effect of damage position on system reliability.
KW - Reliability
KW - Acoustics
KW - Monitoring
KW - Automotive engineering
KW - Elastodynamic Finite Inegration Technique
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528218
DO - https://doi.org/10.1109/TUFFC.2021.3084898
VL - 68
IS - 10
SP - 3156
EP - 3173
AN - OPUS4-52821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Plichta, T.
A1 - Sirjovona, V.
A1 - Zvonek, M.
A1 - Kalinka, Gerhard
A1 - Cech, V.
T1 - The Adhesion of Plasma Nanocoatings Controls the Shear Properties of GF/Polyester Composite
N2 - High-performance fibre-reinforced polymer composites are important construction materials based not only on the specific properties of the reinforcing fibres and the flexible polymer Matrix but also on the compatible properties of the composite interphase. First, oxygen-free (a-CSi:H) and oxygen-binding (a-CSiO:H) plasma nanocoatings of different mechanical and tribological properties were deposited on planar silicon dioxide substrates that closely mimic E-glass. The nanoscratch test was used to characterize the nanocoating adhesion expressed in terms of critical normal load and work of adhesion. Next, the same nanocoatings were deposited on E-glass fibres, which were used as reinforcements in the polyester composite to affect its interphase properties. The shear properties of the polymer composite were characterized by macro- and micromechanical tests, namely a short beam shear test to determine the short-beam strength and a single fibre push-out test to determine the interfacial shear strength. The results of the polymer composites showed a strong correlation between the short-beam strength and the interfacial shear strength, proving that both tests are sensitive to changes in fibre-matrix adhesion due to different surface modifications of glass fibres (GF).
Finally, a strong correlation between the shear properties of the GF/polyester composite and the adhesion of the plasma nanocoating expressed through the work of adhesion was demonstrated.
Thus, increasing the work of adhesion of plasma nanocoatings from 0.8 to 1.5 mJ·m−2 increased the short-beam strength from 23.1 to 45.2 MPa. The results confirmed that the work of adhesion is a more suitable parameter in characterising the level of nanocoating adhesion in comparison with the critical normal load.
KW - Mechanical properties
KW - Plasma nanocoatings
KW - Glass fibre
KW - Polymer composite
KW - Short-beam strength
KW - Interfacial shear strength
KW - Work of adhesion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521844
DO - https://doi.org/10.3390/polym13040593
VL - 13
IS - 4
SP - 593
PB - MDPI
CY - Basel,Schweiz
AN - OPUS4-52184
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seeger, Stefan
A1 - Osan, J.
A1 - Czömpöly, O.
A1 - Gross, A.
A1 - Stosnach, H.
A1 - Stabile, L.
A1 - Ochsenkuehn-Petropoulou, M.
A1 - Tsakanika, L.
A1 - Lymperopoulou, T.
A1 - Goddard, S.
A1 - Fiebig, M.
A1 - Gaie-Levrel, F.
A1 - Kayser, Y.
A1 - Beckhoff, B.
T1 - Quantification of Element Mass Concentrations in Ambient Aerosols by Combination of Cascade Impactor Sampling and Mobile Total Reflection X-ray Fluorescence Spectroscopy
N2 - Quantitative chemical analysis of airborne particulate matter (PM) is vital for the understanding of health effects in indoor and outdoor environments, as well as for enforcing EU air quality regulations. Typically, airborne particles are sampled over long time periods on filters, followed by lab-based analysis, e.g., with inductively coupled plasma mass spectrometry (ICP-MS). During the EURAMET EMPIR AEROMET project, cascade impactor aerosol sampling is combined for the first time with on-site total reflection X-ray fluorescence (TXRF) spectroscopy to develop a tool for quantifying particle element compositions within short time intervals and even on-site. This makes variations of aerosol chemistry observable with time resolution only a few hours and with good size resolution in the PM10 range. The study investigates the proof of principles of this methodological approach. Acrylic discs and silicon wafers are shown to be suitable impactor carriers with sufficiently smooth and clean surfaces, and a non-destructive elemental mass concentration measurement with a lower limit of detection around 10 pg/m3 could be achieved. We demonstrate the traceability of field TXRF measurements to a radiometrically calibrated TXRF reference, and the results from both analytical methods correspond satisfactorily.
KW - TXRF
KW - Reference method
KW - Cascade impactor
KW - Ambient aerosols
KW - Particles
KW - Air quality monitoring
KW - Element mass concentration
KW - Size resolved chemical composition
KW - Time resolved chemical composition
KW - ICP-MS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521860
UR - http://www.aerometproject.com/
DO - https://doi.org/10.3390/atmos12030309
SN - 2073-4433
VL - 12
IS - 3
SP - 309
EP - 337
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-52186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wosniok, Aleksander
A1 - Jansen, R.
A1 - Cheng, L.
A1 - Chruscicki, Sebastian
T1 - Ortsaufgelöste Zustandsüberwachung von Brückenbauwerken mittels faseroptischer Sensoren
N2 - In der vorliegenden Studie wurde der Einfluss der statischen Verkehrsbelastung auf die geringen Durchbiegungseffekte in der Betonkonstruktion einer bestehenden Brücke mittels ortsauflösender faseroptischer Sensoren untersucht. Dabei tragen die Ergebnisse der an der Amsterdamer Brücke 705 durchgeführten Belastungstests wesentlich zum Verständnis des Strukturverhaltens bei. Das Konzept der statischen Belastung basierte auf dem Einsatz von zwei 36-Tonnen-Lastwagen, die an mehreren vorbestimmten Stellen auf der Brücke anhielten. Die auf diese Weise aufgebrachte Last führte zu ortsabhängigen kleinen Durchbiegungseffekten, die als lokale Längsdehnung der an der Unterseite der Brücke integrierten Sensorfaser aufgezeichnet wurden. Die reflektometrischen Messungen beruhten auf dem Prinzip genannt TW-COTDR (Tunable Wavelength Coherent Optical Time Domain Reflectometry). Die Messgenauigkeit lag im Bereich von 0,5 µm/m.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Frequenzbereichsreflektometrie
KW - Ortsaufgelöste Fasersensorik
KW - Rayleigh-Streuung
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526752
UR - https://jahrestagung.dgzfp.de/Programm#P73
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-52675
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fürst, Richard
A1 - Fürst, E.
A1 - Vlach, T.
A1 - Repka, J.
A1 - Pokorny, M.
A1 - Mozer, V.
T1 - Use of Cement Suspension as an Alternative Matrix Material for Textile-Reinforced Concrete
N2 - Textile-reinforced concrete (TRC) is a material consisting of high-performance concrete (HPC) and tensile reinforcement comprised of carbon roving with epoxy resin matrix. However, the problem of low epoxy resin resistance at higher temperatures persists. In this work, an alternative to the epoxy resin matrix, a non-combustible cement suspension (cement milk) which has proven stability at elevated temperatures, was evaluated. In the first part of the work, microscopic research was carried out to determine the distribution of particle sizes in the cement suspension. Subsequently, five series of plate samples differing in the type of cement and the method of textile reinforcement saturation were designed and prepared. Mechanical experiments (four-point bending tests) were carried out to verify the properties of each sample type. It was found that the highest efficiency of carbon roving saturation was achieved by using finer ground cement (CEM 52.5) and the pressure saturation method. Moreover, this solution also exhibited the best results in the four-point bending test. Finally, the use of CEM 52.5 in the cement matrix appears to be a feasible variant for TRC constructions that could overcome problems with its low temperature resistance.
KW - Textile-reinforced concrete
KW - High-performance concrete
KW - Carbon fibers
KW - Cement matrix
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527100
DO - https://doi.org/10.3390/ma14092127
SN - 1996-1944
VL - 14
IS - 9
SP - 2127
PB - MDPI
CY - Basel
AN - OPUS4-52710
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reuter, T.
A1 - Plotzki, David
A1 - Borges de Oliveira, F.
A1 - Hausotte, T.
T1 - Simulative Untersuchung des Einflusses von Bildrauschen auf dimensionelle Messungen mit industriellen Computertomografen
N2 - Die industrielle Röntgen-Computertomografie (CT) etabliert sich für die Anwendung in der dimensionellen Messtechnik. Sie bietet als zerstörungsfreies Messverfahren das Potential, sowohl innen- als auch außenliegende Merkmale holistisch zu erfassen. Für die Bestimmung der Güte eines Messwerts muss die dem Messwert zugeordnete Messunsicherheit ermittelt werden. Dabei kann, nach derzeitigem Stand der Technik und Normung, die aufgabenspezifische Messunsicherheit nach VDI/VDE 2630 Blatt 2.1 nur unter hohem Aufwand mit einer Vielzahl an experimentellen Wiederholmessungen ermittelt werden. Ziel diverser Forschungs-projekte zu diesem Thema ist es daher, eine numerische Messunsicherheitsbestimmung zu erreichen. Dafür ist es notwendig, alle signifikanten Einflussgrößen zu erfassen, deren Unsicherheitsbeiträge zu bestimmen und zu bewerten. In diesem Beitrag wird der Einfluss des Bildrauschens auf verschiedene dimensionelle Messgrößen simulativ untersucht. Mithilfe eines prismatischen Prüfkörpers, der eine Vielzahl an Geometrieelementen aufweist, werden verschiedene Messgrößen unterschiedlicher Komplexität betrachtet. Ziel ist es, für diese Messgrößen zu testen, wie diese auf das Bildrauschen reagieren. Dieses wird dabei durch das Signal-Rausch-Verhältnis (SNR) der Projektionsgrauwerte beschrieben und variiert. Es werden Wiederholsimulationen durchgeführt, damit eine statistische Aussage über die Verteilung der Messwerte möglich ist und der Einfluss des Rauschens auf verschiedene Messgrößen individuell beurteilt werden kann. Das Simulationsszenario wird so gestaltet, dass lediglich das Bildrauschen Einfluss auf die Messung hat. Die berechneten Verteilungsbreiten lassen mit sinkendem SNR eine deutliche Zunahme erkennen, insbesondere bei der Bestimmung von Formabweichungen. Simuliert wird mit der Software aRTist 2.10 (BAM).
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Rauschen
KW - Computertomografie
KW - Dimensionelle Messung
KW - Simulation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527144
SP - 1
EP - 11
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. (DGZfP)
CY - Berlin
AN - OPUS4-52714
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ecke, Alexander
A1 - Bohm, Konrad
A1 - Schneider, Rudolf
T1 - Magnetpartikelbasierte Immunoassays als vielseitiges Werkzeug für die Umweltanalytik
N2 - Der Bedarf nach schnellen und kostengünstigen Analysemethoden in der (Trink-)Wasseranalytik steigt mit dem zunehmenden Eintrag pharmazeutisch aktiver Substanzen in die Umwelt.
Insbesondere die Kontamination mit Antibiotika erscheint neben ökotoxikologischen Effekten vor allem in Hinblick auf die Evolution resistenter Keime im Wasser besorgniserregend.
Wir berichten hier über die Entwicklung eines magnetpartikelbasierten Immunoassays (MBBA) zur Detektion des Breitbandantibiotikums Amoxicillin (AMX) in Wasserproben, der im Vergleich zum entsprechenden Enzyme-linked Immunosorbent Assay (ELISA) eine wesentlich kürzere Analysendauer sowie einen breiteren Messbereich mit niedrigerer Nachweisgrenze aufweist. Das angewendete Assayprinzip ist dabei leicht auf weitere Analyten übertragbar und ermöglicht die Implementierung in einen Immunosensor.
KW - Magnetpartikel
KW - Amoxicillin
KW - Immunoassay
KW - Wasser
KW - Antikörper
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527366
UR - https://www.gdch.de/netzwerk-strukturen/fachstrukturen/umweltchemie-und-oekotoxikologie/publikationen/mitteilungen/archiv/2021.html
SN - 1618-3258
VL - 27
IS - 2
SP - 48
EP - 51
PB - Gesellschaft Deutscher Chemiker (GDCh)
CY - Frankfurt/Main
AN - OPUS4-52736
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kraus, David
A1 - Trappe, Volker
T1 - Transverse damage in glass fiber reinforced polymer under thermo-mechanical loading
N2 - In this study, the thermomechanical damage behavior of a glass fiber reinforced polymer material is investigated. The coefficients of thermal expansion of the composite as well as the matrix are measured in a wide temperature range. Quasi-static experiments with neat resin, unidirectional and multidirectional laminates are performed as well as fatigue experiments in a temperature range from 213 K to 343 K. This study focusses on the matrix damage due to fiber-parallel loading. A correlation between matrix effort, the dilatational strain energy of the matrix and the damage state of the specimen is demonstrated. It is shown that a fatigue life assessment can be performed with the aid of a temperature-independent master fatigue curve.
KW - Composite
KW - Glass fiber reinforced polymer
KW - Thermo-mechanics
KW - Fatigue
KW - Damage
KW - Temperature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527462
DO - https://doi.org/10.1016/j.jcomc.2021.100147
SN - 2666-6820
VL - 5
SP - 100147
PB - Elsevier B.V.
AN - OPUS4-52746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Bruchno, Martin
A1 - Thomas, Goedecke
T1 - Release of Powdery or Granular Substances from Intact Dangerous Goods Bags During Road Transport - Analysis of the Causes and Development of a Test Concept
N2 - The leaks of dangerous goods from actually intact bags detected in the years 2018 to 2020 tend to be at an almost constant high level. These releases of powdery or granular dangerous goods represent violations of the sift-proofness required in the dangerous goods regulations. This article first analyzes the causes.
The components of the bags that are affected by leaks are micro-perforations, joins and closures, in particular internal sleeve valves. A distinction must be made between bags closed in conformity with or contrary to the manufacturer's instructions. The particle release is determined by a number of influencing factors of the filling substance, the packaging and other boundary conditions.
Therefore, a comprehensive test concept is developed in this work, which takes all these factors into account. The application of this test concept facilitates the planning of the test setup and the experiments. On this basis, the complex mechanisms involved in the release of solid substances can be systematically investigated in the test laboratory.
To prevent releases of powdery or granular substances from intact bags, it is necessary that the user has access to the closing instructions and the relevant properties of the test substance used for the design type approval. Further experimental investigations are needed to assess whether filling substances change their properties during transport and whether this enables them to escape.
KW - Bags
KW - Dangerous goods packagings
KW - Leak
KW - Particles
KW - Sift-proofness
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527287
DO - https://doi.org/10.1002/pts.2575
SN - 0894-3214
VL - 34
IS - 7
SP - 435
EP - 446
PB - Wiley
AN - OPUS4-52728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ecke, Alexander
A1 - Schneider, Rudolf
T1 - Pitfalls in the Immunochemical Determination of β-Lactam Antibiotics in Water
N2 - Contamination of waters with pharmaceuticals is an alarming problem as it may support the evolution of antimicrobial resistance. Therefore, fast and cost-effective analytical methods for potential on-site analysis are desired in order to control the water quality and assure the safety of its use as a source of drinking water. Antibody-based methods, such as the enzyme-linked immunosorbent assay (ELISA), can be helpful in this regard but can also have certain pitfalls in store, depending on the analyte. As shown here for the class of β-lactam antibiotics, hydrolysis of the β-lactam ring is a key factor in the immunochemical analysis as it influences antibody recognition. With the antibody used in this study, the limit of detection (LOD) in the immunoassay could be significantly reduced by hydrolysis for the five tested penicillins, with the lowest LOD for carbenicillin (0.2 nmol/L) and the greatest impact on penicillins G and V (reduction by 85%). In addition to enhanced quantification, our strategy also provides access to information about the degree of hydrolysis in water samples as shown for the most abundant penicillin amoxicillin.
KW - ELISA
KW - Immunoassay
KW - β-Lactam
KW - Amoxicillin
KW - Hydrolysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522832
DO - https://doi.org/10.3390/antibiotics10030298
SN - 2079-6382
VL - 10
IS - 3
SP - 298
PB - MDPI
CY - Basel, CH
AN - OPUS4-52283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Zutta Villate, J. M.
ED - Zutta Villate, J. M.
T1 - Combined cell and nanoparticle models for TOPAS to study radiation dose enhancement in cell organelles
N2 - Dose enhancement by gold nanoparticles (AuNP) increases the biological effectiveness of Radiation damage in biomolecules and tissue. To apply them effectively during cancer therapy their influence on the locally delivered dose has to be determined. Hereby, the AuNP locations strongly influence the energy deposit in the nucleus, mitochondria, membrane and the cytosol of the targeted cells. To estimate these effects, particle scattering simulations are applied. In general, different approaches for modeling the AuNP and their distribution within the cell are possible. In this work, two newly developed continuous and discrete-geometric models for simulations of AuNP in cells are presented.
These models are applicable to simulations of internal emitters and external radiation sources. Most of the current studies on AuNP focus on external beam therapy. In contrast, we apply the presented models in Monte-Carlo particle scattering simulations to characterize the energy deposit in cell organelles by radioactive 198AuNP. They emit beta and gamma rays and are therefore considered for applications with solid tumors. Differences in local dose enhancement between randomly distributed and nucleus targeted nanoparticles are compared. Hereby nucleus targeted nanoparticels showed a strong local dose enhancement in the radio sensitive nucleus. These results are the foundation for future experimental work which aims to obtain a mechanistic understanding of cell death induced by radioactive 198Au.
KW - AuNP
KW - Beta decay
KW - Brachytherapy
KW - Cancer treatment
KW - DNA
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - LEE
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - Ectoine
KW - OH radicals
KW - Radiation damage
KW - Radiationtherapy
KW - Radioactive decay
KW - Simulation
KW - Beta particle
KW - Clustered nanoparticles
KW - Gamma ray
KW - Low energy electrons
KW - Particle scattering
KW - Radiolysis
KW - Livermore model
KW - Penelope model
KW - TOPAS
KW - TOPAS-nbio
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523276
DO - https://doi.org/10.1038/s41598-021-85964-2
SN - 2045-2322
VL - 11
IS - 1
SP - 6721
PB - Springer Nature
AN - OPUS4-52327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Even, Morgane
A1 - Juritsch, Elevtheria
A1 - Richter, Matthias
T1 - Measurement of very volatile organic compounds (VVOCs) in indoor air by sorbent-based active sampling: Identifying the gaps towards standardisation
N2 - The ISO 16000-6 standard describes a method for the determination of volatile organic compounds (VOCs) in indoor and test chamber air by sorbent-based active sampling, thermal desorption and gas chromatography coupled with mass spectrometry (GC/MS). It also gives directions to adapt this methodology to very volatile organic compounds (VVOCs). Indeed, toxicologically based guideline values are being implemented for these compounds and it becomes necessary to measure them. But a comprehensive and robust measurement method is lacking. This work highlights the points that still need to be explored towards the standardisation of a suitable procedure: investigations on sorbent combinations, the suitability of chromatography columns and the use of gaseous standards are required. The biggest challenge remains in the fact that strong sorbents adsorb water together with VVOCs. Water may impair the analysis and the optimal approach to eliminate it is still to be found and integrated into the sampling strategy.
KW - Solvents
KW - Air analysis
KW - VOC
KW - Thermal desorption
KW - Gas chromatography
KW - ISO 16000-6
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523919
DO - https://doi.org/10.1016/j.trac.2021.116265
VL - 140
SP - 116265
PB - Elsevier B.V.
AN - OPUS4-52391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Florian, Camilo
A1 - Fischer, Daniel
A1 - Freiberg, K.
A1 - Duwe, M.
A1 - Sahre, Mario
A1 - Schneider, S.
A1 - Hertwig, Andreas
A1 - Krüger, Jörg
A1 - Rettenmayr, M.
A1 - Beck, Uwe
A1 - Undisz, A.
A1 - Bonse, Jörn
T1 - Single Femtosecond Laser-Pulse-Induced Superficial Amorphization and Re-Crystallization of Silicon
N2 - Superficial amorphization and re-crystallization of silicon in <111> and <100> orientation after irradiation by femtosecond laser pulses (790 nm, 30 fs) are studied using optical imaging and transmission electron microscopy. Spectroscopic imaging ellipsometry (SIE) allows fast data acquisition at multiple wavelengths and provides experimental data for calculating nanometric amorphous layer thickness profiles with micrometric lateral resolution based on a thin-film layer model. For a radially Gaussian laser beam and at moderate peak fluences above the melting and below the ablation thresholds, laterally parabolic amorphous layer profiles with maximum thicknesses of several tens of nanometers were quantitatively attained. The accuracy of the calculations is verified experimentally by high-resolution transmission electron microscopy (HRTEM) and energy dispersive X-ray spectroscopy (STEM-EDX). Along with topographic information obtained by atomic force microscopy (AFM), a comprehensive picture of the superficial re-solidification of silicon after local melting by femtosecond laser pulses is drawn.
KW - Femtosecond laser
KW - Silicon
KW - Amorphization
KW - Crystallization
KW - Spectroscopic imaging ellipsometry
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523687
UR - https://www.mdpi.com/1996-1944/14/7/1651
DO - https://doi.org/10.3390/ma14071651
SN - 1996-1944
VL - 14
IS - 7
SP - 1651-1
EP - 1651-21
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-52368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holstein, Tanja
A1 - Kurths, J.
A1 - Wiedermann, M.
T1 - Optimization of coupling and global collapse in diffusively coupled socio-ecological resource exploitation networks
N2 - Single- and multi-layer complex networks have been proven as a powerful tool to study the dynamics within social, technological, or natural systems. An often observed common goal is to optimize these systems for specific purposes by minimizing certain costs while maximizing a desired output. Acknowledging that especially real-world systems from the coupled socio-ecological realm are highly intertwined this work exemplifies that in such systems the optimization of a certain subsystem, e.g. to increase the resilience against external pressure in an ecological network, may unexpectedly diminish the stability of the whole coupled system. For this purpose we utilize an adaptation of a previously proposed conceptual bi-layer network model composed of an ecological network of diffusively coupled resources co-evolving with a social network of interacting agents that harvest these resources and learn each other’s strategies depending on individual success. We derive an optimal coupling strength that prevents collapse in as many resources as possible if one assumes that the agents’ strategies remain constant over time.
We then show that if agents socially learn and adapt strategies according to their neighbors’ success, this optimal coupling strength is revealed to be a critical parameter above which the probability for a global collapse in terms of irreversibly depleted resources is high—an effect that we denote the tragedy of the optimizer. We thus find that measures which stabilize the Dynamics within a certain part of a larger co-evolutionary system may unexpectedly cause the emergence of novel undesired globally stable states. Our results therefore underline the importance of holistic approaches for managing socio-ecological systems because stabilizing effects which focus on single subsystems may be counter-beneficial for the system as a whole.
KW - Network science
KW - Complex systems
KW - Socio-ecological models
KW - Non linear dynamics
KW - Physics
KW - Physics and society
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524176
DO - https://doi.org/10.1088/1367-2630/abe0db
VL - 23
IS - 3
SP - 033027
PB - IOP Publishing
CY - Bristol, England
AN - OPUS4-52417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästner, L.
A1 - Ahmadi, Samim
A1 - Jonietz, Florian
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
A1 - Lambrecht, J.
T1 - Classification of Spot-Welded Joints in Laser Thermography Data Using Convolutional Neural Networks
N2 - Spot welding is a crucial process step in various industries. However, classification of spot welding quality is still a tedious process due to the complexity and sensitivity of the test material, which drain conventional approaches to its limits. In this article, we propose an approach for quality inspection of spot weldings using images from laser thermography data. We propose data preparation approaches based on the underlying physics of spot-welded joints, heated with pulsed laser thermography by analyzing the intensity over time and derive dedicated data filters to generate training datasets. Subsequently, we utilize convolutional neural networks to classify weld quality and compare the performance of different models against each other. We achieve competitive results in terms of classifying the different welding quality classes compared to traditional approaches, reaching an accuracy of more than 95 percent. Finally, we explore the effect of different augmentation methods.
KW - Active thermal imaging
KW - Laser thermography
KW - Spot-welded joints
KW - Convolutional neural network
KW - Classification
KW - Data processing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524216
DO - https://doi.org/10.1109/ACCESS.2021.3063672
VL - 9
SP - 48303
EP - 48312
AN - OPUS4-52421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahrbach, M.
A1 - Friedrich, Sebastian
A1 - Behle, H.
A1 - Xu, Min
A1 - Cappella, Brunero
A1 - Brand, U.
A1 - Peiner, E.
T1 - Customized piezoresistive microprobes for combined imaging of topography and mechanical properties
N2 - Customized piezoresistive cantilever microprobes with a deflection range of 120 μm and silicon tips of 100 μm height were operated in a Cypher AFM showing their functionality for measuring topography together with stiffness, adhesion, and viscoelastic properties of thin films.
KW - Cantilever microprobe
KW - Piezoresistive
KW - Atomic force microscopy
KW - Force-distance curves
KW - Contact resonance
KW - Lubricants
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524225
DO - https://doi.org/10.1016/j.measen.2021.100042
VL - 15
SP - 100042
PB - Elsevier Ltd.
AN - OPUS4-52422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, M. A.
A1 - Khan, I.
A1 - Opitz, P.
A1 - Hartmann, J:
A1 - Ashraf, M.
A1 - Qurashi, A.
A1 - Prädel, L.
A1 - Panthöfer, M.
A1 - Cossmer, Antje
A1 - Pfeifer, Jens
A1 - Simon, Fabian
A1 - von der Au, Marcus
A1 - Meermann, Björn
A1 - Mondeshki, M.
A1 - Tahir, M. N.
A1 - Tremel, W.
T1 - A Generalized Method for High-Speed Fluorination of Metal Oxides by Spark Plasma Sintering Yields Ta3O7F and TaO2F with High Photocatalytic Activity for Oxygen Evolution from Water
N2 - A general method to carry out the fluorination of metal oxides with poly(tetrafluoroethylene) (PTFE, Teflon) waste by spark plasma sintering (SPS) on a minute scale with Teflon is reported. The potential of this new approach is highlighted by the following results. i) The tantalum oxyfluorides Ta3O7F and TaO2F are obtained from plastic scrap without using toxic or caustic chemicals for fluorination. ii) Short reaction times (minutes rather than days) reduce the process time the energy costs by almost three orders of magnitude. iii) The oxyfluorides Ta3O7F and TaO2F are produced in gram amounts of nanoparticles. Their synthesis can be upscaled to the kg range with industrial sintering equipment. iv) SPS processing changes the catalytic properties: while conventionally prepared Ta3O7F and TaO2F show little catalytic activity, SPS-prepared Ta3O7F and TaO2F exhibit high activity for photocatalytic oxygen evolution, reaching photoconversion efficiencies up to 24.7% and applied bias to photoconversion values of 0.86%. This study shows that the materials properties are dictated by the processing which poses new challenges to understand and predict the underlying factors.
KW - Fluorination
KW - Oxygen evolution reaction
KW - Photocatalysis
KW - Spark plasma sintering
KW - Tantalum oxyfluorides
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524329
DO - https://doi.org/10.1002/adma.202007434
VL - 23
IS - 20
SP - 7434
PB - Wiley‐VCH GmbH
AN - OPUS4-52432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hernandez-Castillo, A. O.
A1 - Bischoff, J.
A1 - Lee, J. H.
A1 - Langenhan, Jennifer
A1 - Karra, M.
A1 - Meijer, G.
A1 - Eibenberger-Arias, S.
T1 - High-resolution UV spectroscopy of 1-indanol
N2 - We report on rotationally resolved laser induced fluorescence (LIF) and vibrationally resolved resonanceenhanced multiphoton ionization (REMPI) spectroscopy of the chiral molecule 1-indanol. Spectra of the S1 ’ S0 electronic transition are recorded in a jet-cooled, pulsed molecular beam. Using two timedelayed pulsed lasers, the lifetimes of the S1 state of the two most stable conformers, referred to as eq1 and ax2, have been determined. The S1 ’ S0 origin bands of these conformers as well as the Transition to a vibrationally excited level in the S1 state of eq1 are recorded with full rotational resolution (25 MHz observed linewidth) by measuring the LIF intensity following excitation with a tuneable, narrowband cw laser. On selected rotationally resolved electronic transitions, Lamb-dips are measured to confirm the Lorentzian lifetime-contribution to the observed lineshapes. The rotationally resolved S1 ’ S0 origin band of a neon-complex of eq1 is measured via LIF as well. The fit of the rotationally resolved LIF spectra of the origin bands to those of an asymmetric rotor yields a standard deviation of about 6 MHz.
The resulting spectroscopic parameters are tabulated and compared to the outcome of ab initio calculations. For both conformers as well as for the Ne-eq1 complex, the geometric structures in the S0 and S1 states are discussed. For all systems, the transition dipole moment is mainly along the a-axis, the contributions along the b- and c-axes being about one order of magnitude smaller.
KW - REMPI
KW - LIF
KW - 1-indanol
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525056
DO - https://doi.org/10.1039/d0cp06170k
VL - 23
IS - 12
SP - 7048
EP - 7056
PB - Royal Society of Chemistry
AN - OPUS4-52505
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schweitzer, T.
A1 - Hörmann, M.
A1 - Bühling, Benjamin
A1 - Bobusch, B.
T1 - Switching Action of a Bistable Fluidic Amplifier for Ultrasonic Testing
N2 - Air-coupled ultrasonic testing is widely used in the industry for the non-destructive testing of compound materials. It provides a fast and efficient way to inspect large concrete civil infrastructures for damage that might lead to catastrophic failure. Due to the large penetration depths required for concrete structures, the use of traditional piezoelectric transducer requires high power electric systems. In this study, a novel fluidic transducer based on a bistable fluidic amplifier is investigated. Previous experiments have shown that the switching action of the device produces a high-power broadband ultrasonic signal. This study will provide further insight into the switching behaviour of the fluidic switch. Therefore, parametric CFD simulations based on compressible supersonic RANS simulations were performed, varying the inlet pressure and velocity profiles for the control flow. Switching times are analyzed with different methods, and it was found that These are mostly independent of the slope of the velocity profile at the control port. Furthermore, it was found that an inversely proportional relationship exists between flow velocity in the throat and the switching time. The results agree with the theoretical background established by experimental studies that can be found in the literature.
KW - Ultrasound
KW - Non-destructive testing
KW - Fluidic devices
KW - Computational fluid dynamics
KW - Concrete
KW - Bistable fluidic amplifier
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525115
DO - https://doi.org/10.3390/fluids6050171
SN - 2311-5521
VL - 6
IS - 5
SP - 171
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ewert, Uwe
A1 - Zscherpel, Uwe
T1 - Aktuelle Entwicklungen in der Normung
N2 - Es wird über die neuen Anforderungen ausgewählter Normen bzw. Normrevisionen informiert und insbesondere auch über die veränderten Parameter, die bei der Prüfpraxis, der Qualitätssicherung in der digitalen Radiographie und bei der Klassifizierung zu berücksichtigen sind. Das wichtigste Projekt ist die Revision der DIN EN ISO 17636-1, -2, RT von Schweißverbindungen, in ISO TC 44 SC 5 WG 1. Hauptaktivität bei ASTM ist gegenwärtig die Überarbeitung der CT-Standards und die Berücksichtigung der Anforderungen an das dimensionelle Messen. Der „Standard Guide for Computed Tomography“, ASTM E 1441, zur Bestimmung von MTF, Kontrast-Detail-Funktion (CDF) und Kontrast-Diskrimination-Diagramm (CDD) wurde revidiert und veröffentlicht. Die Mehrzahl der Hersteller von CT-Anlagen bietet entsprechende Software-Tools an. Weiterhin werden neue Festkörperentwürfe zur Charakterisierung von CT-Anlagen vorgestellt. Die folgenden Revisionen sind bei ASTM derzeit in Bearbeitung: ASTM E 2445, „CR Long Term Stability“ nach einem Round Robin-Test und für DDAs der Standard zur System-Charakterisierung, ASTM E2597/E2597M−14, und zur „DDA Long Term Stability“. Das Spider-Net-Diagramm zur Klassifizierung von DDAs wird um die Position „ISO Material Thickness limit“ erweitert. Der Standard EN 12679 zur Messung der Größe von Gammastrahlern wurde nach Revision unter Berücksichtigung von digitalen Messverfahren veröffentlicht. Die Revision der Standardserie EN 12543 zur Messung der Brennfleckgröße ist mit Verzögerung in Überarbeitung, um die digitalen Detektoren und Messmöglichkeiten mit Bildverarbeitungsprogrammen zu berücksichtigen. Die Messprozedur für Lochkameras wurde grundlegend revidiert und ist harmonisiert mit ASTM E 1165-12(2017). Die gemessenen Brennflecke unterscheiden sich und passen besser zu den Unschärfe-Messungen
mit Doppeldraht BPKs (ISO 19232-5:2018) bei Vergrößerung. Ein Entwurf zur Messung der Brennfleckgröße von nano-Fokusröhren und Mikro-Fokusröhren (< 5 µm) wird derzeit vom Europäischen Metrologie-Programm EMPIR gefördert. Es wird über erste Ergebnisse
informiert.
T2 - 19. Seminar Aktuelle Fragen der Durchstrahlungsprüfung und Strahlenschutz
CY - Online meeting
DA - 23.03.2021
KW - Industrielle Durchstrahlungsprüfung
KW - ZfP
KW - Normentwicklung RT
KW - DIN ISO ASTM International
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524149
SP - Paper 8, 1
EP - Paper 8, 15
PB - DGZfP
AN - OPUS4-52414
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmadi, Samim
A1 - Thummerer, G.
A1 - Breitwieser, S.
A1 - Mayr, G.
A1 - Lecompagnon, Julien
A1 - Burgholzer, P.
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
T1 - Multi-dimensional reconstruction of internal defects in additively manufactured steel using photothermal super resolution combined with virtual wave based image processing
N2 - We combine three different approaches to greatly enhance the defect reconstruction ability of active thermographic testing. As experimental approach, laser-based structured illumination is performed in a step-wise manner. As an intermediate signal processing step, the virtual wave concept is used in order to effectively convert the notoriously difficult to solve diffusion-based inverse problem into a somewhat milder wavebased inverse problem. As a final step, a compressed-sensing based optimization procedure is applied which efficiently solves the inverse problem by making advantage of the joint sparsity of multiple blind measurements. To evaluate our proposed processing technique, we investigate an additively manufactured stainless steel sample with eight internal defects. The concerted super resolution approach is compared to conventional thermographic reconstruction techniques and shows an at least four times better spatial resolution.
KW - Active thermography
KW - Additive manufacturing
KW - Stainless steel
KW - ADMM
KW - Block regularization
KW - Internal defects
KW - Joint sparsity
KW - Laser excitation
KW - Multi-dimensional reconstruction
KW - Photothermal super resolution
KW - Virtual waves
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525330
DO - https://doi.org/10.1109/tii.2021.3054411
SN - 1551-3203
SN - 1941-0050
VL - 17
IS - 11
SP - 7368
EP - 7378
PB - IEEE
CY - New York, NY
AN - OPUS4-52533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brauckmann, C.
A1 - Pramann, A.
A1 - Rienitz, O.
A1 - Schulze, A.
A1 - Phukphatthanachai, Pranee
A1 - Vogl, Jochen
T1 - Combining Isotope Dilution and Standard Addition—Elemental Analysis in Complex Samples
N2 - A new method combining isotope dilution mass spectrometry (IDMS) and standard addition has been developed to determine the mass fractions w of different elements in complex matrices: (a) silicon in aqueous tetramethylammonium hydroxide (TMAH), (b) sulfur in biodiesel fuel, and (c) iron bound to transferrin in human serum. All measurements were carried out using inductively coupled plasma mass spectrometry (ICP–MS). The method requires the gravimetric preparation of several blends (bi)—each consisting of roughly the same masses (mx,i) of the sample solution (x) and my,i of a spike solution (y) plus different masses (mz,i) of a reference solution (z).
Only these masses and the isotope ratios (Rb,i) in the blends and reference and spike solutions have to be measured. The derivation of the underlying equations based on linear regression is presented and compared to a related concept reported by Pagliano and Meija. The uncertainties achievable, e.g., in the case of the Si blank in extremely pure TMAH of urel (w(Si)) = 90% (linear regression method, this work) and urel (w(Si)) = 150% (the method reported by Pagliano and Meija) seem to suggest better applicability of the new method in practical use due to the higher robustness of regression analysis.
KW - Isotope dilution mass spectrometry
KW - tandard addition
KW - ICP-MS
KW - lank characterization
KW - Silicon
KW - Sulfur
KW - Transferrin
KW - Tetramethylammonium hydroxide
KW - Biodiesel fuel
KW - Human serum
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526376
DO - https://doi.org/10.3390/molecules26092649
VL - 26
IS - 9
SP - 2649
PB - MDPI
CY - Basel
AN - OPUS4-52637
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shipov, A.
A1 - Zaslansky, P.
A1 - Riesemeier, Heinrich
A1 - Segev, G.
A1 - Atkins, A.
A1 - Kalish-Achrai, N.
A1 - Weiner, S.
A1 - Shahar, R.
T1 - The influence of estrogen deficiency on the structural and mechanical properties of rat cortical bone
N2 - Background. Post-menopausal osteoporosis is a common health problem worldwide, most commonly caused by estrogen deficiency. Most of the information regarding the skeletal effects of this disease relates to trabecular bone, while cortical bone is less studied. The purpose of this study was to evaluate the influence of estrogen deficiency on the structure and mechanical properties of cortical bone.
Methods. Eight ovariectomized (OVH) and eight intact (control) Sprague Dawley rats were used. Structural features of femoral cortical bone were studied by light microscopy, scanning electron microscopy and synchrotron-based microcomputer-tomography and their mechanical properties determined by nano-indentation.
Results. Cortical bone of both study groups contains two distinct regions: organized
circumferential lamellae and disordered bone with highly mineralized cartilaginous islands. Lacunar volume was lower in the OVH group both in the lamellar and disorganized regions (182 ± 75 µm3 vs 232 ± 106 µm3 , P < 0.001 and 195 ± 86 µm3 vs. 247 ± 106 µm3 , P < 0.001, respectively). Lacunar density was also lower in both bone regions of the OVH group (40 ± 18 ×103 lacunae/mm3 vs. 47 ± 9×103 lacunae/mm3
in the lamellar region, P = 0.003 and 63 ± 18×103 lacunae/mm3
vs. 75 ± 13×103 lacunae/mm3 in the disorganized region, P < 0.001). Vascular canal volume was lower in the disorganized region of the bone in the OVH group compared to the same Region in the control group (P < 0.001). Indentation moduli were not different between the study groups in both bone regions.
Discussion. Changes to cortical bone associated with estrogen deficiency in rats require high-resolution methods for detection. Caution is required in the application of These results to humans due to major structural differences between human and rat bone.
KW - Estrogen
KW - Disorganized bone
KW - Rat
KW - Lacunae
KW - Ovariectomy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520798
DO - https://doi.org/10.7717/peerj.10213
VL - 9
SP - e10213
AN - OPUS4-52079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Anzt, H.
A1 - Bach, F.
A1 - Druskat, S.
A1 - Löffler, F.
A1 - Loewe, A.
A1 - Renard, B. Y.
A1 - Seemann, G.
A1 - Struck, A.
A1 - Achhammer, E.
A1 - Aggarwal, P.
A1 - Appel, F.
A1 - Bader, M.
A1 - Brusch, L.
A1 - Busse, C.
A1 - Chourdakis, G.
A1 - Dabrowski, P. W.
A1 - Ebert, P.
A1 - Flemisch, B.
A1 - Friedl, S.
A1 - Fritzsch, B.
A1 - Funk, M. D.
A1 - Gast, V.
A1 - Goth, F.
A1 - Grad, J.
A1 - Hegewald, J.
A1 - Hermann, S.
A1 - Hohmann, F.
A1 - Janosch, S.
A1 - Kutra, D.
A1 - Linxweiler, J.
A1 - Muth, Thilo
A1 - Peters-Kottig, W.
A1 - Rack, F.
A1 - Raters, F. H. C.
A1 - Rave, S.
A1 - Reina, G.
A1 - Reißig, M.
A1 - Ropinski, T.
A1 - Schaarschmidt, J.
A1 - Seibold, H.
A1 - Thiele, J. P.
A1 - Uekermann, B.
A1 - Unger, S.
A1 - Weeber, R.
T1 - An environment for sustainable research software in Germany and beyond: current state, open challenges, and call for action
N2 - Research software has become a central asset in academic research. It optimizes existing and enables new research methods, implements and embeds research knowledge, and constitutes an essential research product in itself. Research software must be sustainable in order to understand, replicate, reproduce, and build upon existing research or conduct new research effectively. In other words, software must be available, discoverable, usable, and adaptable to new needs, both now and in the future. Research software therefore requires an environment that supports sustainability.
Hence, a change is needed in the way research software development and maintenance are currently motivated, incentivized, funded, structurally and infrastructurally supported, and legally treated. Failing to do so will threaten the quality and validity of research. In this paper, we identify challenges for research software sustainability in Germany and beyond, in terms of motivation, selection, research software engineering personnel, funding, infrastructure, and legal aspects. Besides researchers, we specifically address political and academic decision-makers to increase awareness of the importance and needs of sustainable research software practices. In particular, we recommend strategies and measures to create an environment for sustainable research software, with the ultimate goal to ensure that software-driven research is valid, reproducible and sustainable, and that software is recognized as a first class citizen in research. This paper is the outcome of two workshops run in Germany in 2019, at deRSE19 - the first International Conference of Research Software Engineers in Germany - and a dedicated DFG-supported follow-up workshop in Berlin.
KW - Research Software
KW - Sustainable Software Development
KW - Academic Software
KW - Software Infrastructure
KW - Software Training
KW - Software Licensing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522029
DO - https://doi.org/10.12688/f1000research.23224.2
VL - 9
SP - 1
EP - 35
AN - OPUS4-52202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech, S.
A1 - Rehberg, M.
A1 - Janke, R.
A1 - Benndorf, D.
A1 - Genzel, Y.
A1 - Muth, Thilo
A1 - Sickmann, A.
A1 - Rapp, E.
A1 - Reichl, U.
T1 - Tracking changes in adaptation to suspension growth for MDCK cells: cell growth correlates with levels of metabolites, enzymes and proteins
N2 - Adaptations of animal cells to growth in suspension culture concern in particular viral vaccine production, where very specific aspects of virus-host cell interaction need to be taken into account to achieve high cell specific yields and overall process productivity. So far, the complexity of alterations on the metabolism, enzyme, and proteome level required for adaptation is only poorly understood. In this study, for the first time, we combined several complex analytical approaches with the aim to track cellular changes on different levels and to unravel interconnections and correlations. Therefore, a Madin-Darby canine kidney (MDCK) suspension cell line, adapted earlier to growth in suspension, was cultivated in a 1-L bioreactor. Cell concentrations and cell volumes, extracellular metabolite concentrations, and intracellular enzyme activities were determined. The experimental data set was used as the input for a segregated growth model that was already applied to describe the growth dynamics of the parental adherent cell line. In addition, the cellular proteome was analyzed by liquid chromatography coupled to tandem mass spectrometry using a label-free protein quantification method to unravel altered cellular processes for the suspension and the adherent cell line. Four regulatory mechanisms were identified as a response of the adaptation of adherent MDCK cells to growth in suspension. These regulatory mechanisms were linked to the proteins caveolin, cadherin-1, and pirin. Combining cell, metabolite, enzyme, and protein measurements with mathematical modeling generated a more holistic view on cellular processes involved in the adaptation of an adherent cell line to suspension growth.
KW - MDCK cell
KW - Proteome
KW - Metabolism
KW - Enzyme activity
KW - Suspension growth
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522070
DO - https://doi.org/10.1007/s00253-021-11150-z
VL - 105
IS - 5
SP - 1861
EP - 1874
PB - Springer
AN - OPUS4-52207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Horender, S.
A1 - Auderset, K.
A1 - Quincey, P.
A1 - Seeger, Stefan
A1 - Skov, S. N.
A1 - Dierschel, K.
A1 - Smith, T. O.M.
A1 - Williams, K.
A1 - Aegerter, C. C.
A1 - Kalbermatter, D. M.
A1 - Gaie-Levrel, F.
A1 - Vasilatou, K.
T1 - Facility for production of ambient-like model aerosols (PALMA) inthe laboratory: application in the intercomparison of automated PMmonitors with the reference gravimetric method
N2 - A new facility has been developed which allows for a stable and reproducible production of ambient-like model aerosols (PALMA) in the laboratory. The set-up consists of multiple aerosol generators, a custom-made flow tube homogeniser, isokinetic sampling probes, and a system to control aerosol temperature and humidity. Model aerosols containing elemental carbon, secondary organic matter from the ozonolysis of α-pinene, inorganic salts such as ammonium sulfate and ammonium nitrate, mineral dust particles,and water were generated under different environmental conditions and at different number and mass concentrations. The aerosol physical and chemical properties were characterised with an array of experimental methods, including scanning mobility particle sizing, ion chromatography, total reflection X-ray fluorescence spectroscopy and thermo-optical analysis. The facility is very versatile and can find applications in the calibration and performance characterisation of aerosol instruments monitoring ambient air. In this study, we performed, as proof of concept, an intercomparison of three different commercial PM (particulate matter) monitors (TEOM1405, DustTrak DRX 8533 and Fidas Frog) with the gravimetric reference method under three simulated environmental scenarios. The results are presented and compared to previous field studies. We believe that the laboratory-based method for simulating ambient aerosols presented here could provide in the future a useful alternative to time-consuming and expensive field campaigns, which are often required for instrument certification and calibration.
KW - Model aerosols
KW - Intercomparison
KW - PM monitors
KW - Aerosol gravimetry
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521342
DO - https://doi.org/10.5194/amt-14-1225-2021
VL - 14
IS - 2
SP - 1225
EP - 1238
PB - Copernicus Publications
AN - OPUS4-52134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frisch, M.
A1 - Laun, J.
A1 - Marquardt, Julien
A1 - Arinchtein, A.
A1 - Bauerfeind, K.
A1 - Bernsmeier, D.
A1 - Bernicke, M.
A1 - Bredow, T.
A1 - Kraehnert, R.
T1 - Bridging experiment and theory: enhancing the electrical conductivities of soft-templated niobium-doped mesoporous titania films†
N2 - Theoretical calculations suggest a strong dependence of electrical conductivity and doping concentration in transition-metal doped titania. Herein, we present a combined theoretical and experimental approach for the prediction of relative phase stability and electrical conductivity in niobium-doped titania as model system.
Our method paves the way towards the development of materials with improved electrical properties.
KW - Electrical conductivity
KW - Prediction relative
KW - Transition-metal doped
KW - System method
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521371
DO - https://doi.org/10.1039/d0cp06544g
SN - 1463-9084
VL - 23
IS - 5
SP - 3219
EP - 3224
PB - Royal Society of Chemistry
AN - OPUS4-52137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schutjajew, K.
A1 - Pampel, Jonas
A1 - Zhang, W.
A1 - Antonietti, M.
A1 - Oschatz, M.
T1 - Influence of pore architecture and chemical structure on the sodium storage in nitrogen‐doped hard carbons
N2 - Hard carbon is the material of choice for sodium ion battery anodes. Capacities comparable to those of lithium/graphite can be reached, but the understanding of the underlying sodium storage mechanisms remains fragmentary. A two‐step process is commonly observed, where sodium first adsorbs to polar sites of the carbon (“sloping region”) and subsequently fills small voids in the material (“plateau region”). To study the impact of nitrogen functionalities and pore geometry on sodium storage, a systematic series of nitrogen‐doped hard carbons is synthesized. The nitrogen content is found to contribute to sloping capacity by binding sodium ions at edges and defects, whereas higher plateau capacities are found for materials with less nitrogen content and more extensive graphene layers, suggesting the formation of 2D sodium structures stabilized by graphene‐like pore walls. In fact, up to 84% of the plateau capacity is measured at potentials less than 0 V versus metallic Na, that is, quasimetallic sodium can be stabilized in such structure motifs. Finally, gas physisorption measurements are related to charge discharge data to identify the energy storage relevant pore architectures. Interestingly, these are pores inaccessible to probe gases and electrolytes, suggesting a new view on such “closed pores” required for efficient sodium storage.
KW - Sodium Ion Batteries
KW - Hard Carbon
KW - Storage Mechanism
KW - Anode
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522529
DO - https://doi.org/10.1002/smll.202006767
VL - 17
IS - 48
SP - 2006767
PB - Wiley Online Library
AN - OPUS4-52252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Legall, Herbert
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - Review of x-ray exposure and safety issues arising from ultra-short pulse laser material processing
N2 - Laser processing with ultra-short laser pulses enables machining of materials
with high accuracy and throughput. The development of novel laser Technologies with laser pulse repetition rates up to the MHz range opened the way for industrial manufacturing processes. From a radiological point of view this evolution is important, because x-ray radiation can be generated as an unwanted side effect in laser material processing. Even if the emitted x-ray dose per pulse is comparably low, the x-ray dose can become hazardous to health at high laser repetition rates. Therefore, radiation protection must be considered. This article provides an overview on the generation and detection of x-rays in laser material processing, as well as on the handling of this radiation risk in the framework of radiological protection.
KW - Ultra-short pulse laser processing
KW - Laser-induced x-ray emission
KW - Radiation protection
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522376
DO - https://doi.org/10.1088/1361-6498/abcb16
VL - 41
IS - 1
SP - R28
EP - R42
AN - OPUS4-52237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.
A1 - Camin, B.
A1 - Hansen, L.
A1 - Chyrkin, A.
A1 - Nolze, Gert
T1 - Synchrotron Sub-μ X-ray Tomography of Kirkendall Porosity in a Diffusion Couple of Nickel-Base Superalloy and Nickel after Annealing at 1250 °C
N2 - Kirkendall porosity that forms during interdiffusion in a diffusion couple of nickel-base superalloy CMSX-10 with pure nickel is investigated. The diffusion experiments are conducted at a temperature of 1250 °C, where the strengthening ƴ'-phase ist partially dissolved. The porosity is studied by X-ray sub-μ tomography with a spatial resolution of about 0.35³ μm³ at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. It is found that depending on the distance from the interface the Kirkendall pores take different shapes: octahedral, rounded pyramidal, drop shaped, dendritic, pear shaped, and joint shapes. Such a variety of pore morphologies indicates a complex multistage process of porosity nucleation and growth under vacancy supersaturation of different degrees. The experimental findings are interpreted on the basis of the results of diffusion modeling. It is shown that the kinetics of porosity growth is essentially influenced by the dissolution of the ƴ'-phase.
KW - Diffusion
KW - Nickel alloys
KW - Porous materials
KW - Synchrotron radiations
KW - Three-dimensional tomographies
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521476
DO - https://doi.org/10.1002/adem.202001220
VL - 23
IS - 4
SP - 1220
PB - Wiley Online Library
AN - OPUS4-52147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Faßbender, Sebastian
A1 - von der Au, Marcus
A1 - Koenig, Maren
A1 - Pelzer, J.
A1 - Piechotta, Christian
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Species-specific isotope dilution analysis of monomethylmercury in sediment using GC/ICP-ToF-MS and comparison with ICP-Q-MS and ICP-SF-MS
N2 - A recently introduced inductively coupled plasma-time-of-flight-mass spectrometer (ICP-ToF-MS) shows enhanced sensitivity compared to previous developments and superior isotope ratio precision compared to other ToF and commonly used single-collector ICP-MS instruments. Following this fact, an improvement for isotope dilution ICP-MS using the new instrumentation has been reported. This study aimed at investigating whether this improvement also meets the requirements of species-specific isotope dilution using GC/ICP-MS, where short transient signals are recorded. The results of the analysis of monomethylmercury (MMHg) of a sediment reference material show that isotope ratio precision of ICP-MS instruments equipped with quadrupole, sector-field, and time-of-flight mass analyzers is similar within a broad range of peak signal-to-noise ratio when analyzing one isotopic system. The procedural limit of quantification (LOQ) for MMHg, expressed as mass fraction of Hg being present as MMHg, w(Hg)MMHg, was similar as well for all investigated instruments and ranged between 0.003 and 0.016 μg/kg. Due to the simultaneous detection capability, the ICP-ToF-MS might, however, be more favorable when several isotopic systems are analyzed within one measurement. In a case study, the GC/ICP-ToF-MS coupling was applied for analysis of MMHg in sediments of Finow Canal, a historic German canal heavily polluted with mercury. Mass fractions between 0.180 and 41 μg/kg (w(Hg)MMHg) for MMHg, and 0.056 and 126 mg/kg (w(Hg)total) for total mercury were found in sediment samples taken from the canal upstream and downstream of a former chemical plant.
KW - Methylmercury
KW - Legacy pollution
KW - Finow Canal
KW - Isotope dilution
KW - Mercury speciation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529967
DO - https://doi.org/10.1007/s00216-021-03497-z
SN - 1618-2642
VL - 413
IS - 21
SP - 5279
EP - 5289
PB - Springer
CY - Berlin
AN - OPUS4-52996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Even, Morgane
A1 - Hutzler, C.
A1 - Wilke, Olaf
A1 - Luch, A.
T1 - Emissions of volatile organic compounds from polymer-based consumer products: comparison of three emission chamber sizes
N2 - The ISO 16000 standard series provide guidelines for emission measurements of volatile organic compounds (VOCs) from building materials. However, polymer-based consumer products such as toys may also release harmful substances into indoor air. In such cases, the existing standard procedures are unsuitable for official control laboratories due to high costs for large emission testing chambers. This paper aims at developing and comparing alternative and more competitive methods for the emission testing of consumer products. The influence of the emission chamber size was investigated as smaller chambers are more suited to the common size of consumer products and may help to reduce the costs of testing. Comparison of the performance of a 203 l emission test chamber with two smaller chambers with the capacity of 24 l and 44 ml, respectively, was carried out by using a polyurethane reference material spiked with 14 VOCs during the course of 28 days. The area-specific emission rates obtained in the small chambers were always similar to those of the 203 l reference chamber after a few hours. This implies that smaller chambers can provide at least useful numbers on the extent of polymer-based consumer product emissions into indoor air, thereby supporting meaningful exposure assessments.
KW - Comparison
KW - Consumer products
KW - Emission chamber
KW - Reference material
KW - Volatile organic compounds
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-493697
DO - https://doi.org/10.1111/ina.12605
VL - 30
IS - 1
SP - 40
EP - 48
PB - Wiley VCH-Verlag
AN - OPUS4-49369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hobmeier, K.
A1 - Cantone, M.
A1 - Nguyen, Q. A.
A1 - Pflüger-Grau, K.
A1 - Kremling, A.
A1 - Kunte, Hans-Jörg
A1 - Pfeiffer, F.
A1 - Marin-Sanguino, A.
T1 - Adaptation to varying salinity in Halomonas elongata: Much more than ectoine accumulation
N2 - The halophilic γ-proteobacterium Halomonas elongata DSM 2581T thrives at salt concentrations well above 10 % NaCl (1.7 M NaCl). A well-known osmoregulatory mechanism is the accumulation of the compatible solute ectoine within the cell in response to osmotic stress. While ectoine accumulation is central to osmoregulation and promotes resistance to high salinity in halophilic bacteria, ectoine has this effect only to a much lesser extent in non-halophiles. We carried out transcriptome analysis of H. elongata grown on two different carbon sources (acetate or glucose), and low (0.17 M NaCl), medium (1 M), and high salinity (2 M) to identify additional mechanisms for adaptation to high saline environments. To avoid a methodological bias, the transcripts were evaluated by applying two methods, DESeq2 and Transcripts Per Million (TPM). The differentially transcribed genes in response to the available carbon sources and salt stress were then compared to the transcriptome profile of Chromohalobacter salexigens, a closely related moderate halophilic bacterium. Transcriptome profiling supports the notion that glucose is degraded via the cytoplasmic Entner-Doudoroff pathway, whereas the Embden-Meyerhoff-Parnas pathway is employed for gluconeogenesis. The machinery of oxidative phosphorylation in H. elongata and C. salexigens differs greatly from that of non-halophilic organisms, and electron flow can occur from quinone to oxygen along four alternative routes. Two of these pathways via cytochrome bo' and cytochrome bd quinol oxidases seem to be upregulated in salt stressed cells. Among the most highly regulated genes in H. elongata and C. salexigens are those encoding chemotaxis and motility proteins, with genes for chemotaxis and flagellar assembly severely downregulated at low salt concentrations. We also compared transcripts at low and high-salt stress (low growth rate) with transcripts at optimal salt concentration and found that the majority of regulated genes were down-regulated in stressed cells, including many genes involved in carbohydrate metabolism, while ribosome synthesis was up-regulated, which is in contrast to what is known from non-halophiles at slow growth. Finally, comparing the acidity of the cytoplasmic proteomes of non-halophiles, extreme halophiles and moderate halophiles suggests adaptation to an increased cytoplasmic ion concentration of H. elongata. Taken together, these results lead us to propose a model for salt tolerance in H. elongata where ion accumulation plays a greater role in salt tolerance than previously assumed.
KW - Ectoine
KW - Osmoadaptation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545608
DO - https://doi.org/10.3389/fmicb.2022.846677
SN - 1664-302X
VL - 13
SP - 1
EP - 19
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54560
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marklein, B.
A1 - Jenning, M.
A1 - Konthur, Zoltán
A1 - Häupl, T.
A1 - Welzel, F.
A1 - Nonhoff, U.
A1 - Krobitsch, S.
A1 - Mulder, D. M.
A1 - Koenders, M. I.
A1 - Joshua, V.
A1 - Cope, A. P.
A1 - Shlomchik, M. J.
A1 - Anders, H.-J.
A1 - Burmester, G. R.
A1 - Hensvold, A.
A1 - Catrina, A. I.
A1 - Rönnelid, J.
A1 - Steiner, G.
A1 - Skriner, K.
T1 - The citrullinated/native index of autoantibodies against hnRNP-DL predicts an individual "window of treatment success" in RA patients
N2 - Background: There is a need for biomarker to identify patients “at risk” for rheumatoid arthritis (risk-RA) and to better predict the therapeutic response and in this study we tested the hypothesis that novel native and citrullinated heterogeneous nuclear ribonucleoprotein (hnRNP)-DL autoantibodies could be possible biomarkers.
Methods: Using protein macroarray and ELISA, epitope recognition against hnRNP-DL was analysed in sera from different developed RA disease and diagnosed SLE patients. Toll-like receptor (TLR) 7/9 and myeloid Differentiation primary response gene 88 (MyD88)-dependency were studied in sera from murine disease models. HnRNP-DL expression in cultivated cells and synovial tissue was analysed by indirect immunofluorescence, immunoblot and immunohistochemistry.
KW - Citrullinated
KW - Rheumatoid arthritis
KW - Protein-modification
KW - Autoantibodies
KW - Antigens
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533682
DO - https://doi.org/10.1186/s13075-021-02603-x
SN - 1478-6362
VL - 23
SP - 1
EP - 16
PB - BioMed Central
CY - London
AN - OPUS4-53368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haeckel, A.
A1 - Ascher, Lena
A1 - Beindorff, N.
A1 - Prasad, S.
A1 - Garczynska, K.
A1 - Guo, J.
A1 - Schellenberger, E.
T1 - Long‑circulating XTEN864‑annexin A5 fusion protein for phosphatidylserine‑related therapeutic applications
N2 - Annexin A5 (anxA5) is a marker for apoptosis, but has also therapeutic potential in cardiovascular diseases, cancer, and, due to apoptotic mimicry, against dangerous viruses, which is limited by the short blood circulation. An 864-amino-acid XTEN polypeptide was fused to anxA5. XTEN864-anxA5 was expressed in Escherichia coli and purified using XTEN as tag.
XTEN864-anxA5 was coupled with DTPA and indium-111. After intravenous or subcutaneous injection of 111In-XTEN864-anxA5, mouse blood samples were collected for blood half-life determination and organ samples for biodistribution using a gamma counter. XTEN864-anxA5 was labeled with 6S-IDCC to confirm binding to apoptotic cells using flow cytometry.
To demonstrate targeting of atherosclerotic plaques, XTEN864-anxA5 was labeled with MeCAT(Ho) and administered intravenously to atherosclerotic ApoE−/−mice. MeCAT(Ho)-XTEN864-anxA5 was detected together with MeCAT(Tm)-MAC-2 macrophage antibodies by imaging mass cytometry (CyTOF) of aortic root sections. The ability of anxA5 to bind apoptotic cells was not affected by XTEN864. The blood half-life of XTEN864-anxA5 was 13 h in mice after IV injection, markedly longer than the 7-min half-life of anxA5. 96 h after injection, highest amounts of XTEN864-anxA5 were found in liver, spleen, and kidney. XTEN864-anxA5 was found to target the adventitia adjacent to atherosclerotic plaques. XTEN864-anxA5 is a long-circulating fusion protein that can be efficiently produced in E. coli and potentially circulates in humans for several days, making it a promising therapeutic drug.
KW - Programmed cell death
KW - LA/ICP-MS Imaging
KW - Medicinal application
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533811
DO - https://doi.org/10.1007/s10495-021-01686-w
VL - 26
IS - 9-10
SP - 534
EP - 547
PB - Springer
AN - OPUS4-53381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rieger, J.
A1 - Colla, V.
A1 - Matino, I.
A1 - Branca, T. A.
A1 - Stubbe, G.
A1 - Panizza, A.
A1 - Brondi, C.
A1 - Falsafi, M.
A1 - Hage, J.
A1 - Wang, X.
A1 - Voraberger, B.
A1 - Fenzl, T.
A1 - Masaguer, V.
A1 - Faraci, E. L.
A1 - di Sante, L.
A1 - Cirilli, F.
A1 - Loose, Florian
A1 - Thaler, C.
A1 - Soto, A.
A1 - Frittella, P.
A1 - Foglio, G.
A1 - di Cecca, C.
A1 - Tellaroli, M.
A1 - Corbella, M.
A1 - Guzzon, M.
A1 - Malfa, E.
A1 - Morillon, A.
A1 - Algermissen, D.
A1 - Peters, K.
A1 - Snaet, D.
T1 - Residue Valorization in the Iron and Steel Industries: Sustainable Solutions for a Cleaner and More Competitive Future Europe
N2 - The steel industry is an important engine for sustainable growth, added value, and high-quality employment within the European Union. It is committed to reducing its CO2 emissions due to production by up to 50% by 2030 compared to 1990′s level by developing and upscaling the technologies required to contribute to European initiatives, such as the Circular Economy Action Plan (CEAP) and the European Green Deal (EGD). The Clean Steel Partnership (CSP, a public–private partnership), which is led by the European Steel Association (EUROFER) and the European Steel Technology Platform (ESTEP), defined technological CO2 mitigation pathways comprising carbon direct avoidance (CDA), smart carbon usage SCU), and a circular economy (CE). CE ap-proaches ensure competitiveness through increased resource efficiency and sustainability and consist of different issues, such as the valorization of steelmaking residues (dusts, slags, sludge) for internal recycling in the steelmaking process, enhanced steel recycling (scrap use), the use of secondary carbon carriers from non-steel sectors as a reducing agent and energy source in the steelmaking process chain, and CE business models (supply chain analyses). The current paper gives an overview of different technological CE approaches as obtained in a dedicated workshop called “Resi4Future—Residue valorization in iron and steel industry: sustainable solutions for a cleaner and more competitive future Europe” that was organized by ESTEP to focus on future challenges toward the final goal of industrial deployment.
KW - Circular economy
KW - Steelmaking residues
KW - Clean steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530350
DO - https://doi.org/10.3390/met11081202
VL - 11
IS - 8
SP - 1202
PB - MDPI
AN - OPUS4-53035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirabella, Francesca
A1 - Müllner, M.
A1 - Touzalin, T.
A1 - Riva, M.
A1 - Jakub, Z.
A1 - Kraushofer, F.
A1 - Schmid, M.
A1 - Koper, M. T. M.
A1 - Parkinson, G. S.
A1 - Diebold, U.
T1 - Ni-modified Fe3O4(001) surface as a simple model system for understanding the oxygen evolution reaction
N2 - Electrochemical water splitting is an environmentally friendly technology to store renewable energy in the form of chemical fuels. Among the earth-abundant first-row transition metal-based catalysts, mixed Ni-Fe oxides have shown promising performance for effective and low-cost catalysis of the oxygen evolution reaction (OER) in alkaline media, but the synergistic roles of Fe and Ni cations in the OER mechanism remain unclear. In this work, we report how addition of Ni changes the reactivity of a model iron oxide catalyst, based on Ni deposited on and incorporated in a magnetite Fe3O4(001) single crystal, using a combination of surface science techniques in ultra-high vacuum such as low energy electron diffraction (LEED), x-ray photoelectron spectroscopy (XPS), low-energy ion scattering (LEIS), and scanning tunneling microscopy (STM), as well as atomic force microscopy (AFM) in air, and electrochemical Methods such as cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in alkaline media. A significant improvement in the OER activity is observed when the top surface presents an iron fraction among the cations in the range of 20-40%, which is in good agreement with what has been observed for powder catalysts. Furthermore, a decrease in the OER overpotential is observed following surface aging in electrolyte for three days. At higher Ni load, AFM shows the growth of a new phase attributed to an (oxy)-hydroxide phase which, according to CV measurements, does not seem to correlate with the surface activity towards OER. EIS suggests that the OER precursor species observed on the clean and Ni-modified surfaces are similar and Fe-centered, but form at lower overpotentials when the surface Fe:Ni ratio is optimized. We propose that the well-defined Fe3O4(001) surface can serve as a model System for understanding the OER mechanism and establishing the structure-reactivity relation on mixed Fe-Ni oxides.
KW - OER
KW - Fe-Ni oxides
KW - Surface science
KW - Electrochemistry
KW - Water splitting
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529231
UR - https://www.sciencedirect.com/science/article/pii/S0013468621009282?via%3Dihub
DO - https://doi.org/10.1016/j.electacta.2021.138638
VL - 389
SP - 138638
PB - Elsevier Ltd.
AN - OPUS4-52923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahlawat, A.
A1 - Seeger, Stefan
A1 - Gottschalk, Martin
A1 - Tuch, T.
A1 - Wiedensohler, A.
T1 - Observation of systematic deviations between Faraday cup aerosol electrometers for varying particle sizes and flow rates - results of the AEROMET FCAE workshop
N2 - Condensation particle counters (CPCs) are widely used for the measurement of aerosol particle number concentrations in the size range from approximately 3 nm to 3 μm. For an SI-traceable calibration of the size-dependent counting efficiency, which is advisable on a regular basis and required in several applications, Faraday cup aerosol electrometers (FCAEs) are considered to be a suitable SI-traceable reference.While the volumetric aerosol inlet flowrate and the electrical current measurement in FCAEs can be related to respective SI references, inter-comparison exercises for FCAEs are still performed on a regular basis to establish reliable uncertainty budgets and to further investigate the influences of designs and operational parameters on comparability. This is strongly demanded in the international community of metrological institutes and aerosol calibration facilities around the world, which provide CPC calibrations. In the present study, the performance of FCAEs was investigated,using Ag test aerosol particles with a 30 nm particle diameter by varying the inlet flowrates from 0.5 l min−1 to 4 l min−1. From our experimental results, significant deviations were observed in FCAE currents at sample flowrates smaller than 1.5 l min−1. It is recommended that these discrepancies should be quantified before an FCAE is used for CPC calibration at low sample flowrates and small particle sizes in the sub-30 nm size range.
KW - Faraday cup aerosol electrometer
KW - CPC calibration
KW - Inter-comparison
KW - Aerosol measurement instruments
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531315
DO - https://doi.org/10.1088/1681-7575/ac0710
SN - 1681-7575
SN - 0026-1394
VL - 58
IS - 5
SP - 1
EP - 8
PB - Institute of Physics (IOP)
CY - Bristol, UK
AN - OPUS4-53131
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - James, G. L.
A1 - Latif, M. T.
A1 - Isa, M. N. M.
A1 - Bakar, M. F. A.
A1 - Yusuf, N. Y. M.
A1 - Broughton, William
A1 - Murad, A. M.
A1 - Abu Bakar, F. D.
T1 - Metagenomic datasets of air samples collected during episodes of severe smoke-haze in Malaysia
N2 - Transboundary emissions of smoke-haze from land and forest fires have recurred annually during the dry period (June to October, over the past few decades) in South East Asia. Hazardous air quality has been recorded in Malaysia during these episodes. Agricultural practices such as slash-and-burn of biomass and peat fires particularly in Sumatera and Kalimantan, Indonesia, have been implicated as the major causes of the haze. Past findings have shown that a diversity of microbes can thrive in air including in smoke-haze polluted air. In this study, metagenomic data were generated to reveal the diversity of microorganisms in air during days with and without haze. Air samples were collected during non-haze (2013A01) and two haze (2013A04 and 2013A05) periods in the month of June 2013. DNA was extracted from the samples, subjected to Multiple Displacement Amplification and whole genome sequencing (Next Generation Sequencing) using the HiSeq 2000 Platform. Extensive bio-informatic analyses of the raw sequence data then followed. Raw reads from these six air samples were deposited in the NCBI SRA databases under Bioproject PRJNA662021 with accession numbers SRX9087478, SRX9087479 and SRX9087480.
KW - Forest fires
KW - Haze Samples
KW - NGS
KW - Multiple Displacement Amplification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528973
DO - https://doi.org/10.1016/j.dib.2021.107124
SN - 2352-3409
VL - 36
SP - 107124
PB - Elsevier Inc.
CY - Amsterdam, Netherlands
AN - OPUS4-52897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Firdous, R.
A1 - Kruschwitz, Sabine
A1 - Stephan, D.
T1 - Sequential learning to accelerate discovery of alkali-activated binders
N2 - Alkali-activated binders (AAB) can provide a clean alternative to conventional cement in terms of CO2 emissions. However, as yet there are no sufficiently accurate material models to effectively predict the AAB properties, thus making optimal mix design highly costly and reducing the attractiveness of such binders. This work adopts sequential learning (SL) in high-dimensional material spaces (consisting of composition and processing data) to find AABs that exhibit desired properties. The SL approach combines machine learning models and feedback from real experiments. For this purpose, 131 data points were collected from different publications. The data sources are described in detail, and the differences between the binders are discussed. The sought-after target property is the compressive strength of the binders after 28 days. The success is benchmarked in terms of the number of experiments required to find materials with the desired strength. The influence of some constraints was systematically analyzed, e.g., the possibility to parallelize the experiments, the influence of the chosen algorithm and the size of the training data set. The results show the advantage of SL, i.e., the amount of data required can potentially be reduced by at least one order of magnitude compared to traditional machine learning models, while at the same time exploiting highly complex information. This brings applications in laboratory practice within reach.
KW - Alkali-activated binders
KW - Machine learning
KW - Sequential learning
KW - Materials by design
KW - Materials informatics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531376
DO - https://doi.org/10.1007/s10853-021-06324-z
SN - 0022-2461
SN - 1573-4803
VL - 56
SP - 15859
EP - 15881
PB - Springer
CY - Dordrecht
AN - OPUS4-53137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Wolf, Marcus
A1 - Kranzmann, Axel
T1 - Corrosion and corrosion fatigue of steels in downhole CCS environment - A summary
N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO₂-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO₃ and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO₂: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
KW - Steel
KW - High alloyed steel
KW - Corrosion
KW - Corrosion fatigue
KW - Carbon capture and storage
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531391
DO - https://doi.org/10.3390/pr9040594
SN - 2227-9717
VL - 9
IS - 4
SP - 1
EP - 33
PB - MDPI
CY - Basel
AN - OPUS4-53139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tokarski, T.
A1 - Nolze, Gert
A1 - Winkelmann, A.
A1 - Rychlowski, L.
A1 - Bala, P.
A1 - Cios, G.
T1 - Transmission Kikuchi diffraction: The impact of the signal-to-noise ratio
N2 - Signal optimization for transmission Kikuchi diffraction (TKD) measurements in the scanning electron microscope is investigated by a comparison of different sample holder designs. An optimized design is presented, which uses a metal shield to efficiently trap the electron beam after transmission through the sample. For comparison, a second holder configuration allows a significant number of the transmitted electrons to scatter back from the surface of the sample holder onto the diffraction camera screen. It is shown that the secondary interaction with the sample holder leads to a significant increase in the background level, as well as to additional noise in the final Kikuchi diffraction signal. The clean TKD signal of the optimized holder design with reduced background scattering makes it possible to use small signal changes in the range of 2% of the camera full dynamic range. As is shown by an analysis of the power spectrum, the signal-to-noise ratio in the processed Kikuchi diffraction patterns is improved by an order of magnitude. As a result, the optimized design allows an increase in pattern signal to noise ratio which may lead to increase in measurement speed and indexing reliability.
KW - EBSD
KW - SEM
KW - Transmission Kikuchi diffraction
KW - Sample holder
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531743
DO - https://doi.org/10.1016/j.ultramic.2021.113372
SN - 0304-3991
SN - 1879-2723
VL - 230
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wosniok, Aleksander
A1 - Krebber, Katerina
T1 - Distributed fiber optic radiation sensors
N2 - In this work, we present our results achieved in several research activities for development of distributed fiber optic radiation sensors using glass and polymer optical fibers. The findings show that both the measurement of the radiation-induced attenuation (RIA) along the entire sensing fiber and the accompanying change in the refractive index of the fiber core can be used for distributed radiation monitoring.
T2 - safeND
CY - Online meeting
DA - 10.11.2021
KW - Distributed fiber optic radiation sensors
KW - Radiation-induced attenuation
KW - Optical fiber sensor
KW - Incoherent optical frequency domain reflectometry
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537531
DO - https://doi.org/10.5194/sand-1-15-2021
VL - 1
SP - 15
EP - 16
AN - OPUS4-53753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Roland
A1 - Heyn, L.
A1 - Jung, Christian
T1 - Indoor exposure to airborne polycyclic aromatic hydrocarbons: A comparison of stir bar sorptive extraction and pump sampling
N2 - Stir bar sorptive extraction (SBSE) was compared with standardized pump sampling regarding the prospects to assess airborne levels of polycyclic aromatic hydrocarbons (PAHs) in indoor environments. A historic railway water tower, which will be preserved as a technical monument for museum purposes, was sampled with both approaches because the built-in insulationmaterial was suspected to release PAHs to the indoor air. The 16 PAHs on the US EPA list were quantified using gas chromatography with mass spectrometric detection in filters from pump sampling after solvent extraction and on SBSE devices after thermal desorption. SBSEwas seen to sample detectable PAHmasseswith excellent repeatability and a congener pattern largely similar to that observed with pump sampling. Congener patterns were however significantly different from that in the PAH source because release from the insulation material is largely triggered by the respective congener vapor pressures. Absolute masses in the ng range sampled by SBSE corresponded to airborne concentrations in the ng L−1 range determined by pump sampling. Principle differences between SBSE and pump sampling as well as prospects of SBSE as cost-effective and versatile complement of pump sampling are discussed.
KW - Polycyclic aromatic hydrocarbons
KW - Adsorption
KW - Extraction
KW - Indoor air
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537427
DO - https://doi.org/10.1002/eng2.12419
VL - 3
IS - 12
SP - 1
EP - 10
PB - John Wiley & Sons Ltd.
AN - OPUS4-53742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Van Den Bossche, T.
A1 - Arntzen, M. O.
A1 - Becher, D.
A1 - Benndorf, D.
A1 - Eijsink, V. G. H.
A1 - Henry, C.
A1 - Jagtap, P. D.
A1 - Jehmlich, N.
A1 - Juste, C.
A1 - Kunath, B. J.
A1 - Mesuere, B.
A1 - Muth, Thilo
A1 - Pope, P. B.
A1 - Seifert, J.
A1 - Tanca, A.
A1 - Uzzau, S.
A1 - Wilmes, P.
A1 - Hettich, R. L.
A1 - Armengaud, J.
T1 - The Metaproteomics Initiative: a coordinated approach for propelling the functional characterization of microbiomes
N2 - Through connecting genomic and metabolic information, metaproteomics is an essential approach for understanding how microbiomes function in space and time. The international metaproteomics community is delighted to announce the launch of the Metaproteomics Initiative (www.metaproteomics.org), the goal of which is to promote dissemination of metaproteomics fundamentals, advancements, and applications through collaborative networking in microbiome research. The Initiative aims to be the central information hub and open meeting place where newcomers and experts interact to communicate, standardize, and accelerate experimental and bioinformatic methodologies in this feld. We invite the entire microbiome community to join and discuss potential synergies at the interfaces with other disciplines, and to collectively promote innovative approaches to gain deeper insights into microbiome functions and dynamics.
KW - Microbiome
KW - Metaproteomics
KW - Networking
KW - Meta-Omics
KW - Interactions
KW - Education
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542290
DO - https://doi.org/10.1186/s40168-021-01176-w
VL - 9
IS - 1
SP - 243
PB - BMC
AN - OPUS4-54229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ecke, Alexander
A1 - Westphalen, Tanja
A1 - Hornung, J.
A1 - Voetz, M.
A1 - Schneider, Rudolf
T1 - A rapid magnetic bead-based immunoassay for sensitive determination of diclofenac
N2 - Increasing contamination of environmental waters with pharmaceuticals represents an emerging threat for the drinking water quality and safety. In this regard, fast and reliable analytical methods are required to allow quick countermeasures in case of contamination. Here, we report the development of a magnetic bead-based immunoassay (MBBA) for the fast and cost-effective determination of the analgesic diclofenac (DCF) in water samples, based on diclofenac-coupled magnetic beads and a robust monoclonal anti-DCF antibody. A novel synthetic strategy for preparation of the beads resulted in an assay that enabled for the determination of diclofenac with a significantly lower limit of detection (400 ng/L) than the respective enzyme-linked immunosorbent assay (ELISA). With shorter incubation times and only one manual washing step required, the assay demands for remarkably shorter time to result (< 45 min) and less equipment than ELISA. Evaluation of assay precision and accuracy with a series of spiked water samples yielded results with low to moderate intra- and inter-assay variations and in good agreement with LC–MS/MS reference analysis. The assay principle can be transferred to other, e.g., microfluidic, formats, as well as applied to other analytes and may replace ELISA as the standard immunochemical method.
KW - Immunoassay
KW - Magnetic beads
KW - Diclofenac
KW - Water analysis
KW - LC-MS/MS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542346
DO - https://doi.org/10.1007/s00216-021-03778-7
SN - 1618-2650
VL - 414
SP - 1563
EP - 1573
PB - Springer
CY - Heidelberg
AN - OPUS4-54234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chubarenko, B.
A1 - Kileso, A.
A1 - Esiukova, E.
A1 - Pinchuk, V.
A1 - Simon, Franz-Georg
T1 - Dataset on geosynthetic material debris contamination of the South-East Baltic shore
N2 - The database gives information on the contamination of the shore of the South-Eastern Baltic with the debris of geosynthetic materials for the period 2018–2020. This new type of coastal pollution enters the natural environment due to the destruction of coastal protection structures and construction activities. The database contains sections:
(1) a list of types of geosynthetic material residues, their photographic images and photographs illustrating examples of finds in natural conditions
[1 List_geosynthetic_debris_SEB],
(2) monitoring data on the contamination of the beach strip with the debris of geotextiles, braids from gabions, geocontainers (big bags), geocells and geogrids for the beaches of the South-Eastern Baltic for the period 2018–2020
[2 Monitoring_geosynthetic_debris_SEB];
(3) statistical distributions of the found geosynthetic debris by size
[3 Scales_geosynthetic_debris_SEB] and (4) results of test surveys on the shores of Lithuania and Poland adjacent to Kaliningrad Oblast.
All data refer to the beaches of the Kaliningrad Oblast (Russia), including the Russian parts of the Vistula and Curonian Spits, but also contains information on a one-time assessment of the pollution of the beaches of the adjacent territories: the Polish shore from the Poland-Russia border on the Vistula Spit to the mouth of the Vistula River, the Lithuanian shore from the border Lithuania-Russia on the Curonian Spit to the border of Latvia-Lithuania. Materials were collected during field surveys within the ERANET-RUS_Plus joint project EI-GEO, ID 212 (RFBR 18-55-76002 ERA_a, BMBF 01DJ18005).
KW - Geosynthetics
KW - Geotextiles
KW - Contamination
KW - Marine littering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541947
DO - https://doi.org/10.1016/j.dib.2021.107778
SN - 2352-3409
VL - 40
SP - 1
EP - 7
PB - Elsevier Inc.
CY - Amsterdam
AN - OPUS4-54194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cros, A.
A1 - Alfaro Espinoza, Gabriela
A1 - De Maria, A.
A1 - Wirth, N. T.
A1 - Nikel, P. I.
T1 - Synthetic metabolism for biohalogenation
N2 - The pressing need for novel bioproduction approaches faces a limitation in the number and type of molecules accessed through synthetic biology. Halogenation is widely used for tuning physicochemical properties of molecules and polymers, but traditional halogenation chemistry often lacks specificity and generates harmful by-products. Here, we pose that deploying synthetic metabolism tailored for biohalogenation represents an unique opportunity towards economically attractive and environmentally friendly organohalide production. On this background, we discuss growth-coupled selection of functional metabolic modules that harness the rich repertoire of biosynthetic and biodegradation capabilities of environmental bacteria for in vivo biohalogenation. By rationally combining these approaches, the chemical landscape of Living cells can accommodate bioproduction of added-value organohalides which, as of today, are obtained by traditional chemistry.
KW - Halogenation
KW - Synthetic metabolism
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542013
DO - https://doi.org/10.1016/j.copbio.2021.11.009
SN - 0958-1669
SN - 1879-0429
VL - 74
SP - 180
EP - 193
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dzekan, D.
A1 - Waske, Anja
A1 - Nielsch, K.
A1 - Fähler, S.
T1 - Efficient and affordable thermomagnetic materials for harvesting low grade waste heat
N2 - Industrial processes release substantial quantities of waste heat, which can be harvested to generate electricity. At present, the conversion of low grade waste heat to electricity relies solely on thermoelectric materials, but such materials are expensive and have low thermodynamic efficiencies. Although thermomagnetic materials may offer a promising alternative, their performance remains to be evaluated, thereby hindering their real-world application. Here, the efficiency and cost effectiveness of thermomagnetic materials are evaluated for the usage in motors, oscillators, and generators for converting waste heat to electricity. The analysis reveals that up to temperature differences of several 10 K, the best thermomagnetic materials have the potential to compete with thermoelectric materials. Importantly, it is found that the price per watt of some thermomagnetic materials is much lower compared to that of present-day thermoelectrics, which can become competitive with conventional power plants. This materials library enables the selection of the best available thermomagnetic materials for harvesting waste heat and gives guidelines for their future development.
KW - Waste heat conversion
KW - Magnetic materials
KW - Thermomagnetic generator
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541493
DO - https://doi.org/10.1063/5.0033970
VL - 9
SP - 1
EP - 9
PB - AIP Publishing
CY - Melville, USA
AN - OPUS4-54149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
T1 - Improving Learning Outcome for GSL (German as a Second Language) Students in a Blended Learning Cumulative Assessment Material Science Course
N2 - First year students especially with migration background and language deficiencies rate material science in mechanical engineering as one of the fundamental courses with high work load and necessity of language skills due to the descriptive nature of the course. Therefore a blended learning course structure using based on inverted classroom teaching scenarios was established. Heart of the self-study period are visualizing peer-to-peer lecture films supported by micro-lectures along with various online teaching materials. Although students with migration background generally scored lower in tests due to the lack of language skills improved learning outcomes are demonstrated in high quality class discussions and in overall understanding. This paper introduces the learning structure and graded activities, evaluates the course and compares results of native German-speaking students to those of students with migration background.
KW - Portfolio
KW - Diversity
KW - Blended learning
KW - Inverted classroom
KW - Lecture films
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541557
DO - https://doi.org/10.17706/ijeeee.2021.11.3.93-100
SN - 2010-3654
VL - 11
IS - 3
SP - 93
EP - 100
AN - OPUS4-54155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Wolf, M.
A1 - Kranzmann, Axel
T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary
N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60 °C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60 °C, brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/− applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
KW - Steel
KW - High alloyed steel
KW - Corrosion fatigue
KW - Cabon capture and storage
KW - CCS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541626
DO - https://doi.org/10.3390/pr9040594
VL - 9
IS - 4
SP - 594
PB - MDPI
AN - OPUS4-54162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ivanov, S.
A1 - Artinov, Antoni
A1 - Zemlyakov, E.
A1 - Karpov, I.
A1 - Rylov, S.
A1 - Em, V.
T1 - Spatiotemporal Evolution of Stress Field during Direct Laser Deposition of Multilayer Thin Wall of Ti-6Al-4V
N2 - The present work seeks to extend the level of understanding of the stress field evolution during direct laser deposition (DLD) of a 3.2 mm thick multilayer wall of Ti-6Al-4V alloy by theoretical and experimental studies. The process conditions were close to the conditions used to produce large-sized structures by the DLD method, resulting in specimens having the same thermal history. A simulation procedure based on the implicit finite element method was developed for the theoretical study of the stress field evolution. The accuracy of the simulation was significantly improved by using experimentally obtained temperature-dependent mechanical properties of the DLD-processed Ti-6Al4V alloy. The residual stress field in the buildup was experimentally measured by neutron diffraction. The stress-free lattice parameter, which is decisive for the measured stresses, was determined using both a plane stress approach and a force-momentum balance. The influence of the inhomogeneity of the residual stress field on the accuracy of the experimental measurement and the validation of the simulation procedure are analyzed and discussed. Based on the numerical results it was found that the non-uniformity of the through-thickness stress distribution reaches a maximum in the central cross-section, while at the buildup ends the stresses are distributed almost uniformly. The components of the principal stresses are tensile at the buildup ends near the substrate. Furthermore, the calculated equivalent plastic strain reaches 5.9% near the buildup end, where the deposited layers are completed, while the plastic strain is practically equal to the experimentally measured ductility of the DLD-processed alloy, which is 6.2%. The experimentally measured residual stresses obtained by the force-momentum balance and the plane stress approach differ slightly from each other.
KW - Direct laser deposition
KW - Finite element simulation
KW - Neutron diffraction
KW - Residual stresses
KW - Ti-6Al-4V
KW - Mechanical properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542444
DO - https://doi.org/10.3390/ma15010263
VL - 15
IS - 263
SP - 1
EP - 20
PB - MDPI
AN - OPUS4-54244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krietsch, Arne
A1 - Reyes Rodriguez, M.
A1 - Kristen, A.
A1 - Kadoke, D.
A1 - Abbas, Z.
A1 - Krause, U.
T1 - Ignition temperatures and flame velocities of metallic nanomaterials
N2 - The production of materials with dimensions in the nanometre range has continued to increase in recent years. In order to ensure safety when handling these products, the hazard potential of such innovative materials must be known. While several studies have already investigated the effects of explosions (such as maximum explosion pressure and maximum pressure rise) of powders with primary particles in the nanometre range, little is known about the ignition temperatures and flame velocities. Therefore, the minimum ignition temperature (MIT) of metallic nano powders (aluminium, iron, copper and zinc) was determined experimentally in a so called Godbert-Greenwald (GG) oven. Furthermore, the flame velocities were determined in a vertical tube. In order to better classify the test results, the tested samples were characterised in detail and the lower explosion limits of the tested dust samples were determined. Values for the burning velocity of aluminium nano powders are higher compared to values of micrometre powders (from literature). While MIT of nanometre aluminium powders is within the range of micrometre samples, MIT of zinc and copper nano powders is lower than values reported in literature for respective micrometre samples.
T2 - 13th Symposium International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE)
CY - Online meeting
DA - 27.07.2021
KW - Dust explosions
KW - Nanomaterial
KW - Flame propagation
KW - Minimum ignition temperature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540930
DO - https://doi.org/10.7795/810.20200724
SP - 591
EP - 605
PB - Physikalisch-Technische Bundesanstalt
AN - OPUS4-54093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krietsch, Arne
A1 - Krause, U.
A1 - Gabel, D.
A1 - Abbas, Z.
A1 - Dufaud, O.
T1 - Quasi-static dispersion of dusts for the determination of lower explosion limits of hybrid mixtures
N2 - Knowledge of explosion limiting concentration of explosible materials is necessary for the design of explosion protection measures. Currently employed methods of testing MEC of a dust cloud or LEL of a hybrid mixture are based on arbitrary assumptions and possess technical limitations that often lead to values of MEC/LEL, which are unrealistically low or poorly reproducible.
This contribution presents an improved method for experimental determination of MEC of a combustible dust cloud or LEL of a flammable gas or hybrid mixture. The new set-up operates under laminar conditions and allows a uniform suspension of dust particles in an open top acrylic glass tube. Dust concentration is measured with the help of infrared sensors installed a few centimeters above and below the ignition source.
In order to evaluate the dependence of MEC on flow front velocity, MEC of lycopodium was determined at four flow velocities. The results show that the flow field intensity does not significantly influence the MEC of lycopodium for the flow ranges tested in this work. Moreover, LEL of hybrid mixtures of lycopodium and methane was also tested at flow velocities of 4.7 cm/s, 5.8 cm/s, 7 cm/s and 11 cm/s and compared with the values obtained from other sources. The results suggest that the requirement of high energy pyrotechnical igniter may be relinquished, provided that a truly homogeneous suspension of dust particles could be achieved.
Moreover, the effect of relative amount of dust and gas, on the course of ignition and flame propagation in hybrid mixtures at their LEL, was studied by the help of high speed videos. For hybrid mixtures of carbonaceous dusts (like lycopodium) at their LEL, ignition occurs in the gas phase, however, flame propagation is only possible through a two-way interaction of dust and gas during the course of combustion.
T2 - 13th Symposium International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE)
CY - Online meeting
DA - 27.07.2020
KW - Dust explosions
KW - Gas explosions
KW - Lower explosion limit
KW - Hybrid mixtures
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540955
DO - https://doi.org/10.7795/810.20200724
SP - 750
EP - 764
PB - Physikalisch-Technische Bundesanstalt
AN - OPUS4-54095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pinomaa, T.
A1 - Lindroos, M.
A1 - Jreidini, P.
A1 - Haapalehto, M.
A1 - Ammar, K.
A1 - Wang, Lei
A1 - Forest, S.
A1 - Provatas, N.
A1 - Laukkanen, A.
T1 - Multiscale analysis of crystalline defect formation in rapid solidification of pure aluminium and aluminium-copper alloys
N2 - Rapid solidification leads to unique microstructural features, where a less studied topic is the formation of various crystalline defects, including high dislocation densities, as well as gradients and splitting of the crystalline orientation. As these defects critically affect the material’s mechanical properties and performance features, it is important to understand the defect formation mechanisms, and how they depend on the solidification conditions and alloying. To illuminate the formation mechanisms of the rapid solidification induced crystalline defects, we conduct a multiscale modelling analysis consisting of bond-order potential-based molecular dynamics (MD), phase field crystal-based amplitude expansion simulations, and sequentially coupled phase field–crystal plasticity simulations. The resulting dislocation densities are quantified and compared to past experiments. The atomistic approaches (MD, PFC) can be used to calibrate continuum level crystal plasticity models, and the framework adds mechanistic insights arising from the multiscale analysis.
This article is part of the theme issue ‘Transport phenomena in complex systems (part 2)’.
KW - Rapid solidification
KW - Crystalline defects
KW - Molecular dynamics
KW - Phase field crystal
KW - Phase field method
KW - Crystal plasticity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542156
DO - https://doi.org/10.1098/rsta.2020.0319
SN - 1364-503X
VL - 380
IS - 2217
SP - 1
EP - 20
PB - Royal Society
CY - London
AN - OPUS4-54215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Tietje, O.
A1 - Borho, N.
A1 - Burkhardt, M.
A1 - Rohr, M.
A1 - Vollpracht, A.
A1 - Weiler, L.
T1 - Environmental impact of construction products on aquatic systems - Principles of an integrated source-path-target concept
N2 - Buildings exposed to water can release undesirable substances which, once transported to environmental compartments, may cause unwanted effects. These exposure pathways need to be investigated and included in risk assessments to safeguard water quality and promote the sustainability of construction materials. The applied materials, exposure conditions, distribution routes and resilience of receiving compartments vary considerably. This demonstrates the need for a consistent concept that integrates knowledge of emission sources, leaching processes, transport pathways, and effects on targets. Such a consistent concept can serve as the basis for environmental risk assessment for several scenarios using experimentally determined emissions. Typically, a source–path–target concept integrates data from standardized leaching tests and models to describe leaching processes, the distribution of substances in the environment and the occurrence of substances at different points of compliance. This article presents an integrated concept for assessing the environmental impact of construction products on aquatic systems and unravels currently existing gaps and necessary actions. This manuscript outlines a source–path–target concept applicable to a large variety of construction products. It is intended to highlight key elements of a holistic evaluation concept that could assist authorities in developing procedures for environmental risk assessments and mitigation measures and identifying knowledge gaps.
KW - Construction products
KW - Environmental impact
KW - Assessment
KW - Concept
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542175
DO - https://doi.org/10.3390/w14020228
SN - 2073-4441
VL - 14
IS - 2
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-54217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Chi-Long
A1 - Seeger, Stefan
T1 - Systematic ranking of filaments regarding their particulate emissions during fused filament fabrication 3D printing by means of a proposed standard test method
N2 - The diversity of fused filament fabrication (FFF) filaments continues to grow rapidly as the popularity of FFF-3D desktop printers for the use as home fabrication devices has been greatly increased in the past decade. Potential harmful emissions and associated health risks when operating indoors have induced many emission studies. However, the lack of standardization of measurements impeded an objectifiable comparison of research findings. Therefore, we designed a chamber-based standard method, i.e., the strand printing method (SPM), which provides a standardized printing procedure and quantifies systematically the particle emission released from individual FFF-3D filaments under controlled conditions. Forty-four marketable filament products were tested. The total number of emitted particles (TP) varied by approximately four orders of magnitude (1E9 ≤ TP ≤ 1E13), indicating that origin of polymers, manufacturer-specific additives, and undeclared impurities have a strong influence. Our results suggest that TP characterizes an individual filament product and particle emissions cannot be categorized by the polymer type (e.g., PLA or ABS) alone. The user's choice of a filament product is therefore decisive for the exposure to released particles during operation. Thus, choosing a filament product awarded for low emissions seems to be an easily achievable preemptive measure to prevent health hazards.
KW - Emission test method
KW - FFF-printing
KW - Particle emission
KW - Indoor air quality
KW - FFF-filament
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545087
DO - https://doi.org/https://doi.org/10.1111/ina.13010
SN - 1600-0668
VL - 32
IS - 3
SP - 1
EP - 12
PB - Wiley
CY - Hoboken, New Jersey, USA
AN - OPUS4-54508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kudela, P.
A1 - Radzienski, M.
A1 - Moix-Bonet, M.
A1 - Willberg, C.
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Tschöke, K.
A1 - Moll, J.
T1 - Dataset on full ultrasonic guided wavefield measurements of a CFRP plate with fully bonded and partially debonded omega stringer
N2 - The fourth dataset dedicated to the Open Guided Waves platform presented in this work aims at a carbon fiber composite plate with an additional omega stringer at constant temperature conditions. The dataset provides full ultrasonic guided wavefields. Two types of signals were used for guided wave excitation, namely chirp signal and tone-burst signal. The chirp signal had a frequency range of 20-500kHz. The tone-burst signals had a form of sine modulated by Hann window with 5 cycles and carrier frequencies 16.5kHz, 50kHz, 100kHz, 200kHz, 300kHz. The piezoceramic actuator used for this purpose was attached to the center of the stringer side surface of the core plate. Three scenarios are provided with this setup: (1) wavefield measurements without damage, (2) wavefield measurements with a local stringer debond and (3) wavefield measurements with a large stringer debond. The defects were caused by impacts performed from the backside of the plate. As result, the stringer feet debonds locally which was verified with conventional ultrasound measurements.
KW - Lamb waves
KW - Composite panel
KW - Impact damage
KW - Damage detection
KW - Scanning laser Doppler vibrometry
KW - Structural health monitoring
KW - Non-destructive evaluation
KW - Open data
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545242
DO - https://doi.org/10.1016/j.dib.2022.108078
SN - 2352-3409
VL - 42
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Kranzmann, Axel
T1 - Understanding the Anomalous Corrosion Behaviour of 17% Chromium Martensitic Stainless Steel in Laboratory CCS-Environment—A Descriptive Approach
N2 - To mitigate carbon dioxide emissions CO2 is compressed and sequestrated into deep geological layers (Carbon Capture and Storage CCS). The corrosion of injection pipe steels is induced when the metal is in contact with CO2 and at the same time the geological saline formation water. Stainless steels X35CrMo17 and X5CrNiCuNb16-4 with approximately 17% Cr show potential as injection pipes to engineer the Northern German Basin geological onshore CCS-site. Static laboratory experiments (T = 60 ◦C, p = 100 bar, 700–8000 h exposure time, aquifer water, CO2-flow rate of 9 L/h) were conducted to evaluate corrosion kinetics. The anomalous surface corrosion phenomena were found to be independent of heat treatment prior to exposure. The corrosion process is described as a function of the atmosphere and diffusion process of ionic species to explain the precipitation mechanism and better estimate the reliability of these particular steels in a downhole CCS environment.
KW - Corrosion
KW - Steel
KW - High alloyed steel
KW - Corrosion mechanism
KW - CCS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545700
DO - https://doi.org/10.3390/cleantechnol4020014
VL - 4
IS - 2
SP - 239
EP - 257
PB - MDPI
AN - OPUS4-54570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Doolette, A.
A1 - Huang, J.
T1 - Combining diffusive gradients in thin-films (DGT) and 31P NMR spectroscopy to determine phosphorus species in soil
N2 - The diffusive gradients in thin-films (DGT) technique shows in many publications a superior correlation to the amount of plant-available phosphorus (P) in soil. However, this technique cannot give information on the plant-available P species in soil. Therefore, we combined DGT with solution 31P nuclear magnetic resonance (NMR) spectroscopy. This was achieved by using a modified DGT device in which the diffusive layer had a larger pore size, the binding layer incorporated an adsorption material with a higher capacity, and the device had a larger exposure area. The spectroscopic investigation was undertaken after elution of the deployed DGT binding layer in a NaOH solution. Adsorption tests using solutions of known organic P compounds showed that a sufficient amount of these compounds could be adsorbed on the binding layer in order for them to be analyzed by solution 31P NMR spectroscopy. Furthermore, various intermediates of the hydrolysis of trimetaphosphate in soil could be also analyzed over time.
KW - Phosphorus
KW - Diffusive gradients in thin-films (DGT)
KW - Passive sampling
KW - fertilizer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545759
DO - https://doi.org/10.1002/ael2.20068
VL - 7
IS - 1
SP - e20068
PB - Wiley online library
AN - OPUS4-54575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - MacLean, J.
A1 - Mayanna, S.
A1 - Benning, L. G.
A1 - Horn, F.
A1 - Bartholomäus, A.
A1 - Wiesner, Yosri
A1 - Wagner, D.
A1 - Liebner, S.
T1 - The terrestrial plastisphere: Diversity and polymer-colonizing potential of plastic-associated microbial communities in soil
N2 - The concept of a ‘plastisphere microbial community’ arose from research on aquatic plastic debris, while the effect of plastics on microbial communities in soils remains poorly understood. Therefore, we examined the inhabiting microbial communities of two plastic debris ecosystems with regard to their diversity and composition relative to plastic-free soils from the same area using 16S rRNA amplicon sequencing. Furthermore, we studied the plastic-colonizing potential of bacteria originating from both study sites as a measure of surface adhesion to UV-weathered polyethylene (PE) using high-magnification field emission scanning electron microscopy (FESEM). The high plastic content of the soils was associated with a reduced alpha diversity and a significantly different structure of the microbial communities. The presence of plastic debris in soils did not specifically enrich bacteria known to degrade plastic, as suggested by earlier studies, but rather shifted the microbial community towards highly abundant autotrophic bacteria potentially tolerant to hydrophobic environments and known to be important for biocrust formation. The bacterial inoculates from both sites formed dense biofilms on the surface and in micrometer-scale surface cracks of the UV-weathered PE chips after 100 days of in vitro incubation with visible threadlike EPS structures and cross-connections enabling surface adhesion. High-resolution FESEM imaging further indicates that the microbial colonization catalyzed some of the surface degradation of PE. In essence, this study suggests the concept of a ‘terrestrial plastisphere’ as a diverse consortium of microorganisms including autotrophs and other pioneering species paving the way for those members of the consortium that may eventually break down the plastic compounds.
KW - Soil microbial community
KW - Polyethylene colonization
KW - Plastic pollution
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542790
DO - https://doi.org/10.3390/microorganisms9091876
VL - 9
IS - 9
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-54279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frisch, M.
A1 - Raza, M. H.
A1 - Ye, M.-Y.
A1 - Sachse, René
A1 - Paul, B.
A1 - Gunder, R.
A1 - Pinna, N.
A1 - Kraehnert, R.
T1 - ALD-coated mesoporous iridium-titanium mixed oxides: Maximizing iridium utilization for an outstanding OER performance
N2 - With the increasing production of renewable energy and concomitant depletion of fossil resources, the demand for efficient water splitting electrocatalysts continues to grow. Iridium (Ir) and iridium oxides (IrOₓ) are currently the most promising candidates for an efficient oxygen evolution reaction (OER) in acidic medium, which remains the bottleneck in water electrolysis. Yet, the extremely high costs for Ir hamper a widespread production of hydrogen (H₂) on an industrial scale. Herein, the authors report a concept for the synthesis of electrode coatings with template-controlled mesoporosity surface-modified with highly active Ir species. The improved utilization of noble metal species relies on the synthesis of soft-templated metal oxide supports and a subsequent shape-conformal deposition of Ir species via atomic layer deposition (ALD) at two different reaction temperatures. The study reveals that a minimum Ir content in the mesoporous titania-based support is mandatory to provide a sufficient electrical bulk conductivity. After ALD, a significantly enhanced OER activity results in dependency of the ALD cycle number and temperature. The most active developed electrocatalyst film achieves an outstanding mass-specific activity of 2622 mA mg(Ir)⁻¹ at 1.60 V(RHE) in a rotating-disc electrode (RDE) setup at 25 °C using 0.5 m H₂SO₄ as a supporting electrolyte.
KW - Acidic oxygen evolution reaction
KW - Atomic layer deposition
KW - Electrocatalysis
KW - Iridium oxide
KW - Soft-templated mesoporous films
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542651
DO - https://doi.org/10.1002/admi.202102035
SN - 2196-7350
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, J.
A1 - Farris, L.
A1 - Nolze, Gert
A1 - Reinsch, Stefan
A1 - Cios, G.
A1 - Tokarski, T.
A1 - Thompson, S.
T1 - Microstructure evolution in Inconel 718 produced by powder bed fusion additive manufacturing
N2 - Inconel 718 is a precipitation strengthened, nickel-based super alloy of interest for the Additive Manufacturing (AM) of low volume, complex parts to reduce production time and cost compared to conventional subtractive processes. The AM process involves repeated rapid melting, solidification and reheating, which exposes the material to non-equilibrium conditions that affect elemental segregation and the subsequent formation of solidification phases, either beneficial or detrimental. These variations are difficult to characterize due to the small length scale within the micron sized melt pool. To understand how the non-equilibrium conditions affect the initial solidification phases and their critical temperatures, a multi-length scale, multi modal approach has been taken to evaluate various methods for identifying the initial phases formed in the as-built Inconel 718 produced by laser-powder bed fusion (L-PBF) additive manufacturing (AM). Using a range of characterization tools from the bulk differential thermal analysis (DTA) and x-ray diffraction (XRD) to spatially resolved images using a variety of electron microscopy tools, a better understanding is obtained of how these minor phases can be properly identified regarding the amount and size, morphology and distribution. Using the most promising characterization techniques for investigation of the as-built specimens, those techniques were used to evaluate the specimens after various heat treatments. During the sequence of heat treatments, the initial as-built dendritic structures recrystallized into well-defined grains whose size was dependent on the temperature. Although the resulting strength was similar in all heat treated specimens, the elongation increased as the grain size was refined due to differences in the precipitated phase distribution and morphology.
KW - Metal additive manufacturing
KW - Inconel 718
KW - Heat treatment
KW - Grain boundary precipitates
KW - Laves phase
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542758
DO - https://doi.org/10.3390/jmmp6010020
SN - 2504-4494
VL - 6
IS - 1
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-54275
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rütters, H.
A1 - Fischer, S.
A1 - Le, Quynh Hoa
A1 - Bettge, Dirk
A1 - Bäßler, Ralph
A1 - Maßmann, J.
A1 - Ostertag-Henning, C.
A1 - Wolf, J. L.
A1 - Pumpa, M.
A1 - Lubenau, U.
A1 - Knauer, S.
A1 - Jaeger, P.
A1 - Neumann, A.
A1 - Svensson, K.
A1 - Pöllmann, H.
A1 - Lempp, C.
A1 - Menezes, F. F.
A1 - Hagemann, B.
T1 - Towards defining reasonable minimum composition thresholds – Impacts of variable CO2 stream compositions on transport, injection and storage
N2 - To set up recommendations on how to define “reasonable minimum composition thresholds” for CO2 streams to access CO2 pipeline networks, we investigated potential impacts of CO2 streams with different and temporally variable compositions and mass flow rates along the CCS chain. All investigations were based on a generic “CCS cluster scenario” in which CO2 streams captured from a spatial cluster of eleven emitters (seven fossil-fired power plants, two cement plants, one refinery and one steel mill) are collected in a regional pipeline network. The resulting CO2 stream (19.78 Mio t impure CO2 per year) is transported in a trunk line (onshore and offshore) and injected into five generic replicate storage structures (Buntsandstein saline aquifers) offshore. Experimental investigations and modeling of selected impacts revealed beneficial as well as adverse impacts of different impurities and their combinations. Overall, no fundamental technical obstacles for transporting, injecting and storing CO2 streams of the considered variable compositions and mass flow rates were observed. We recommend to define minimum composition thresholds for each specific CCS project through limiting
i) the overall CO2 content,
ii) maximum contents of relevant impurities or elements,
iii) acceptable variability of concentrations of critical impurities, and defining impurity combinations to be avoided.
KW - Impurities
KW - CO2 quality
KW - Pipeline network
KW - Whole-chain CCS scenario
KW - Recommendations
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543004
DO - https://doi.org/10.1016/j.ijggc.2022.103589
SN - 1750-5836
VL - 114
SP - 1
EP - 14
PB - Elsevier
CY - New York, NY
AN - OPUS4-54300
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kang, Y.
A1 - Nack, L. M.
A1 - Liu, Y.
A1 - Qi, B.
A1 - Huang, Y.
A1 - Liu, Z.
A1 - Chakraborty, I.
A1 - Schulz, F.
A1 - Ahmed, A. A. A.
A1 - Poveda, M. C.
A1 - Hafizi, F.
A1 - Roy, S.
A1 - Mutas, M.
A1 - Holzapfel, M.
A1 - Sanchez-Cano, C.
A1 - Wegner, Karl David
A1 - Feliu, N.
A1 - Parak, W. J.
T1 - Quantitative considerations about the size dependence of cellular entry and excretion of colloidal nanoparticles for different cell types
N2 - Most studies about the interaction of nanoparticles (NPs) with cells have focused on how the physicochemical properties of NPs will influence their uptake by cells. However, much less is known about their potential excretion from cells. However, to control and manipulate the number of NPs in a cell, both cellular uptake and excretion must be studied quantitatively. Monitoring the intracellular and extracellular amount of NPs over time (after residual noninternalized NPs have been removed) enables one to disentangle the influences of cell proliferation and exocytosis, the major pathways for the reduction of NPs per cell. Proliferation depends on the type of cells, while exocytosis depends in addition on properties of the NPs, such as their size. Examples are given herein on the role of these two different processes for different cells and NPs.
KW - Cell proliferation
KW - Exocytosis
KW - Gold nanoparticles
KW - Quantum dots
KW - Fluorescence
KW - Uptake studies
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543476
DO - https://doi.org/10.1007/s40828-021-00159-6
SN - 2199-3793
VL - 8
IS - 1
SP - 1
EP - 8
PB - Springer
CY - Berlin
AN - OPUS4-54347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Oesch, T.
A1 - Mielentz, Frank
A1 - Meinel, Dietmar
A1 - Spyridis, P.
T1 - Non-Destructive Multi-Method Assessment of Steel Fiber Orientation in Concrete
N2 - Integration of fiber reinforcement in high-performance cementitious materials has become widely applied in many fields of construction. One of the most investigated advantages of steel Fiber reinforced concrete (SFRC) is the deceleration of crack growth and hence its improved sustainability.
Additional benefits are associated with its structural properties, as fibers can significantly increase the ductility and the tensile strength of concrete. In some applications it is even possible to entirely replace the conventional reinforcement, leading to significant logistical and environmental benefits.
Fiber reinforcement can, however, have critical disadvantages and even hinder the Performance of concrete, since it can induce an anisotropic material behavior of the mixture if the fibers are not appropriately oriented. For a safe use of SFRC in the future, reliable non-destructive testing (NDT) methods need to be identified to assess the fibers’ orientation in hardened concrete. In this study,
ultrasonic material testing, electrical impedance testing, and X-ray computed tomography have been investigated for this purpose using specially produced samples with biased or random Fiber orientations. We demonstrate the capabilities of each of these NDT techniques for fiber orientation measurements and draw conclusions based on these results about the most promising areas for future research and development.
KW - Spectral induced polarization
KW - Steel fiber reiniforced concrete
KW - Fiber orientation
KW - Non-destructive testing
KW - Micro-computed tomography
KW - Ultrasound
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543520
DO - https://doi.org/10.3390/app12020697
VL - 12
IS - 2
SP - 1
EP - 14
PB - MDPI
CY - Basel Switzerland
AN - OPUS4-54352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Golian, M.
A1 - Bien, T.
A1 - Schmelzle, S.
A1 - Esparza Mora, Margy Alejandra
A1 - McMahon, Dino Peter
A1 - Dreisewerd, K.
A1 - Buellesbach, J.
ED - Appel, Arthur G.
T1 - Neglected Very Long-Chain Hydrocarbons and the Incorporation of Body Surface Area Metrics Reveal Novel Perspectives for Cuticular Profile Analysis in Insects
N2 - Most of our knowledge on insect cuticular hydrocarbons (CHCs) stems from analytical techniques based on gas-chromatography coupled with mass spectrometry (GC-MS). However, this method has its limits under standard conditions, particularly in detecting compounds beyond a chain length of around C40. Here, we compare the CHC chain length range detectable by GC-MS with the range assessed by silver-assisted laser desorption/ionization mass spectrometry (Ag-LDI-MS), a novel and rarely applied technique on insect CHCs, in seven species of the order Blattodea. For all tested species, we unveiled a considerable range of very long-chain CHCs up to C58, which are not detectable by standard GC-MS technology. This indicates that general studies on insect CHCs May frequently miss compounds in this range, and we encourage future studies to implement analytical techniques extending the conventionally accessed chain length range. Furthermore, we incorporate 3D scanned insect body surface areas as an additional factor for the comparative quantification of extracted CHC amounts between our study species. CHC quantity distributions differed considerably when adjusted for body surface areas as opposed to directly assessing extracted CHC amounts, suggesting that a more accurate evaluation of relative CHC quantities can be achieved by taking body surface areas into account.
KW - Cuticular hydrocarbons
KW - Blattodea
KW - GC-MS
KW - Ag-LDI-MS
KW - Chemical ecology
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543530
DO - https://doi.org/10.3390/insects13010083
VL - 13
IS - 1
SP - 2
EP - 10
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-54353
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brandt, S.
A1 - Brozowski, Frank
A1 - Horn, Wolfgang
A1 - Plehn, W.
A1 - Müller, B.
T1 - Weiterentwicklung des Geruchsmessverfahrens für Bauprodukte (Teil II): Anwendung eines Adapters und vereinfachtes Bewertungsverfahren
T1 - Further Development of the Odour Measurement Method for Building Products (Part II)
N2 - Zur Weiterentwicklung der Probenpräsentation wurde ein Adapter entwickelt, der Emissionsprüfkammer und Bewertungstrichter miteinander verbindet und dadurch eine der direkten Messung vergleichbare Geruchsbewertung ermöglicht. Die analytischen Messungen zeigen, dass es kaum Unterschiede in der Zusammensetzung der Probenluft in der Kammer im Vergleich zum Probenbehälter gibt. Bei den olfaktorischen Messungen kam es jedoch bei der Bewertung der Probenluft mit Hilfe des Adapters zu Minderbefunden. Anschließende Untersuchungen zeigten, dass beim Ausschalten des Geräts Umgebungsluft über den Trichter in den Adapter strömt und zu einer Verdünnung der Probenluft führt. Um dies zu vermeiden, werden derzeit weitere Messungen durchgeführt.
Eine weitere Versuchsreihe wurde durchgeführt, um den Messaufwand bei der Bewertung der empfundenen Intensität zu reduzieren. Die entwickelte „größer-oder-kleiner/gleich“ Abfrage kann hier hilfreich sein. Die Untersuchungen im Luftqualitätslabor und im Rahmen eines Ringversuches mit verschiedenen Laboren, zeigen, dass die Abfrage in fast allen Fällen zu den gleichen Ergebnissen führt, wie die normgerechte aber aufwendigere Ermittlung der empfundenen Intensität mithilfe des Vergleichsmaßstabes.
N2 - For technical improvement of sample presentation an adapter was developed to connect the emission test chamber with the evaluation funnel and thus enabling a more direct measurement. The analytical measurements demonstrate that the air has a very similar composition sampled at the funnel or in the emission test chamber. The results of the olfactory measurements show overall that the intensities determined using the adapter are often reported as lower. Further investigations have shown that air backflow via the funnel into the sample container of the adapter may be the cause. This has to be avoided in future.
Another experimental series was carried out to reduce the measurement effort of evaluation of perceived intensity. Here application of the developed ‘greater than, or less than/equal to’ survey could be helpful. The results of the measurements in the air quality lab and in the frame of a round robin test indicate, that the survey leads to the same evaluation as the more complex determination of perceived intensity with standard method.
KW - Geruchsmessung
KW - VOC-Emission
KW - Bauprodukte
KW - Bewertungsverfahren
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549875
UR - http://www.gefahrstoffe.de
SN - 0949-8036
SN - 1436-4891
VL - 82
IS - 3-4
SP - 83
EP - 89
PB - VDI Fachmedien
CY - Düsseldorf
AN - OPUS4-54987
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hufschläger, Daniel
A1 - Gaal, Mate
A1 - Ahmadzadeh, Majid
T1 - Simulation und Vermessung von thermoakustischen Schallquellen
N2 - Zur Simulation des Schallfeldes von beliebig geformten konventionellen Schallquellen existieren viele Ansätze (EFIT, GPSS). Sie alle basieren auf der Annahme eines monochromatischen akustischen Signals, was meist eine gültige Annäherung darstellt. Allerdings sind bei thermoakustischen Quellen aufgrund ihrer Funktionsweise und der hohen Bandbreite viele der existierenden Ansätze nicht direkt anwendbar und können Beobachtungen bei der Vermessung von thermoakustischen Wandlern nicht vollständig abbilden und erklären.
In diesem Beitrag wurde die bekannte Methode der generalisierten Punktquellensynthese (GPSS) für die Berechnung von Schallfeldern von thermoakustischen Schallquellen angewendet. Dabei gehen zahlreiche Parameter wie die Dicke und Geometrie der leitfähigen Schicht, Krümmung des Substrats, sowie die Signalform der Anregung in die Simulation ein. Neu an dem präsentierten Ansatz ist die Abweichung von der üblichen monochromatischen Annäherung und die Berücksichtigung der großen Bandbreite von thermoakustischen Wandlern. Für die Validierung der Simulationen wurden Schallfelder von Quellen mit bekannter Anregung und Geometrie breitbandig durch ein optisches Mikrofon vermessen.
T2 - DGZfP Jahrestagung
CY - Kassel, Germany
DA - 23.05.2022
KW - Thermoacoustics
KW - Sensor characterization
KW - Simulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549944
SP - 1
EP - 7
AN - OPUS4-54994
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hufschläger, Daniel
A1 - Gaal, Mate
A1 - Gohlke, Dirk
A1 - Weise, Matthias
A1 - Szewieczek, A.
A1 - Hillger, W.
A1 - Ilse, D.
T1 - Array-Prüfköpfe für luftgekoppelte Ultraschallprüfung
N2 - Seit Jahren stellt die luftgekoppelte Ultraschallprüfung eine etablierte Alternative zur konventionellen Prüfung von Leichtbaukomponenten aus den Bereichen Luft- und Raumfahrt sowie Automotive dar. Im Gegenteil zur flüssigkeitsgekoppelten Prüfung in Kontakt oder im Tauchbecken ist sie weniger invasiv und bietet daher zeitliche und finanzielle Anreize.
Normalerweise wird die luftgekoppelte Prüfung mit Einzelelementschwingern in Durchschallung realisiert, wohingegen die Gruppenstrahlertechnik bereits Industriestandard im Bereich der Kontakttechnik darstellt. Die damit verbundenen Vorteile wie die aktive Fokussierung oder, die gezielte Manipulation des Einschallwinkels zur Anregung von geführten Wellen, finden im Bereich der luftgekoppelten Prüfung dabei noch wenig Anwendung.
Im Rahmen dieses Beitrags stellen wir die ersten Zwischenergebnisse des geförderten Projektes „PALUP – Phased- Array-Technik für Luftultraschall-Prüfungen“ vor. Ziel des Projektes ist die Entwicklung von Mehrelementschwingern auf Basis von zellulären Kunststoffen, die Entwicklung einer dedizierten Pulserstufe im Kilovoltbereich, sowie die nötige rauscharme messtechnische Auswertung jedes Einzelelements.
T2 - DGZfP Jahrestagung
CY - Kassel, Germany
DA - 23.05.2022
KW - Phased array
KW - Air-coupled ultrasound
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549954
SP - 1
EP - 7
AN - OPUS4-54995
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jiang, C.
A1 - Xie, G.
A1 - Wu, Dejian
A1 - Yan, T.
A1 - Chen, S.
A1 - Zhao, P.
A1 - Wu, Z.
A1 - Li, W.
T1 - Experimental investigation on an energy-efficient floor heating system with intelligent control: A case study in Chengdu, China
N2 - The space heating system accounts for 20%~50% of building energy consumption, and may lead to energy waste due to unreasonable controls. In this study, an energy-efficient floor heating system with intelligent control was proposed to improve energy efficiency of the system. In order to validate the concept of the proposed intelligent control, an experimental system was designed and constructed in Chengdu, China. Temperature, control cycle and energy consumption were then studied under different control strategies. The result shows that a larger flow rate of supply water will result in a longer control cycle and a lower control frequency, i.e., the average control cycle at 7 L min−1 is 1.7 h during the test day, while it is 1.5 h at 5 L min−1. Moreover, adopting water with a higher temperature and flow rate could achieve a higher efficiency of the system. The energy consumptions in case 1 (5 L min−1, 50 °C), case 2 (5 L min−1, 55 °C), case 5 (7 L min−1, 55 °C) and case 6 (7 L min−1, 60 °C) are 4746 kJ, 3534 kJ, 3093 kJ and 3028 kJ, respectively. Based on the experimental data, the supply water temperature is suggested to set lower than 60 °C considering human comfort.
KW - Floor heating
KW - Intelligent control
KW - Experimental
KW - Energy consumption
KW - Control strategy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550522
DO - https://doi.org/10.1016/j.csite.2021.101094
SN - 2214-157X
VL - 26
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-55052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieksmeyer, T.
A1 - He, S.
A1 - Esparza Mora, Margy Alejandra
A1 - Jiang, S.
A1 - Petrasiunaite, V.
A1 - Kuropka, B.
A1 - Banasiak, Ronald
A1 - Julseth, M. J.
A1 - Weise, C.
A1 - Johnston, P. R.
A1 - Rodriguez-Rojas, A.
A1 - McMahon, Dino Peter
T1 - Eating in a losing cause: Limited benefit of modifed macronutrient consumption following infection in the oriental cockroach Blatta orientalis
N2 - Background: Host–pathogen interactions can lead to dramatic changes in host feeding behaviour. One aspect of this includes self-medication, where infected individuals consume substances such as toxins or alter their macronutrient consumption to enhance immune competence. Another widely adopted animal response to infection is illness-induced anorexia, which is thought to assist host immunity directly or by limiting the nutritional resources available to pathogens. Here, we recorded macronutrient preferences of the global pest cockroach, Blatta orientalis to investigate how shifts in host macronutrient dietary preference and quantity of carbohydrate (C) and protein (P) interact with immunity following bacterial infection.
Results: We fnd that B. orientalis avoids diets enriched for P under normal conditions, and that high P diets reduce cockroach survival in the long term. However, following bacterial challenge, cockroaches signifcantly reduced their overall nutrient intake, particularly of carbohydrates, and increased the relative ratio of protein (P:C) consumed. Surprisingly, these behavioural shifts had a limited efect on cockroach immunity and survival, with minor changes to immune protein abundance and antimicrobial activity between individuals placed on diferent diets, regardless of infection status.
Conclusions: We show that cockroach feeding behaviour can be modulated by a pathogen, resulting in an illness-induced anorexia-like feeding response and a shift from a C-enriched to a more P:C equal diet. However, our results also indicate that such responses do not provide signifcant immune protection in B. orientalis, suggesting that the host’s dietary shift might also result from random rather than directed behaviour. The lack of an apparent beneft of the shift in feeding behaviour highlights a possible reduced importance of diet in immune regulation in these invasive animals, although further investigations employing pathogens with alternative infection strategies are warranted.
KW - Animal immune system
KW - A key interface
KW - Host and symbiont ecology
KW - Behavioural mechanisms
KW - Biotic environment
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550022
DO - https://doi.org/10.1186/s12862-022-02007-8
SN - 2730-7182
VL - 22
IS - 1
SP - 1
EP - 14
PB - Springer Nature
CY - London, UK
AN - OPUS4-55002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lamoriniere, S.
A1 - Mitchell, P. J.
A1 - Ho, K.
A1 - Kalinka, Gerhard
A1 - Shaffer, M. S. P.
A1 - Bismarck, A.
T1 - Carbon nanotube enhanced carbon Fibre-Poly(ether ether ketone) interfaces in model hierarchical composites
N2 - Poly (ether ether ketone) (PEEK) has a high continuous service temperature, excellent mechanical properties, and good solvent and abrasion resistance, which can be further improved through the addition of carbon nanotubes (CNTs). CNT-PEEK nanocomposites are promising matrices for continuous carbon fibre composites; powder processing can mitigate the high melt viscosities in these systems. In this study, model single fibre (hierarchical) composites were produced by embedding sized and desized carbon fibres in nanocomposite CNTPEEK powders followed by single fibre pull-out tests to assess interfacial characteristics. Carbon fibre-PEEK interfacial shear strength is typically 40–45 MPa. Increasing CNT loadings increased fibre-matrix interfacial shear strength linearly up to ~70 MPa at 5.0 wt%, which was attributed to the CNT-based mechanical modification of the PEEK matrix. Apparent interfacial shear strength was inversely correlated with the embedded fibre length irrespective of carbon fibre sizing or CNT loading, indicating brittle fracture of the fibre-matrix interface.
Pulled out carbon fibres were still coated with the matrix, which indicated strong adhesion at the interface in all samples, likely related to a transcrystalline region. Adhesion was, however, negatively affected by the presence of epoxy sizings. Frictional shear strength was independent of embedded fibre length and CNT content for all samples.
KW - Keywords: Poly(ether ether ketone)
KW - Carbon fibres
KW - Carbon nanotubes
KW - Interfacial strength
KW - Debonding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550052
DO - https://doi.org/10.1016/j.compscitech.2022.109327
SN - 0266-3538
VL - 221
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-55005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prohaska, T.
A1 - Irrgeher, J.
A1 - Benefield, J.
A1 - Böhlke, J. K.
A1 - Chesson, L. A.
A1 - Coplen, T. B.
A1 - Ding, T.
A1 - Dunn, P. J. H.
A1 - Gröning, M.
A1 - Holden, N. E.
A1 - Meijer, H. A. J.
A1 - Moossen, H.
A1 - Possolo, A.
A1 - Takahashi, Y.
A1 - Vogl, Jochen
A1 - Walczyk, T.
A1 - Wang, J.
A1 - Wieser, M. E.
A1 - Yoneda, S.
A1 - Zhu, X.-K.
A1 - Meija, J.
T1 - Standard atomic weights of the elements 2021 (IUPAC Technical Report)
N2 - Following the reviews of atomic-weight determinations and other cognate data in 2015, 2017, 2019 and 2021, the IUPAC (International Union of Pure and Applied Chemistry) Commission on Isotopic Abundances and Atomic Weights (CIAAW) reports changes of standard atomic weights. The symbol Ar(E) was selected for standard atomic weight of an element to distinguish it from the atomic weight of an element E in a specific substance P, designated Ar(E, P). The CIAAW has changed the values of the standard atomic weights of five elements based on recent determinations of terrestrial isotopic abundances:
Ar (argon): from 39.948 ± 0.001 to [39.792, 39.963]
Hf (hafnium): from 178.49 ± 0.02 to 178.486 ± 0.006
Ir (iridium): from 192.217 ± 0.003 to 192.217 ± 0.002
Pb (lead): from 207.2 ± 0.1 to [206.14, 207.94]
Yb (ytterbium): from 173.054 ± 0.005 to 173.045 ± 0.010
The standard atomic weight of argon and lead have changed to an interval to reflect that the natural variation in isotopic composition exceeds the measurement uncertainty of Ar(Ar) and Ar(Pb) in a specific substance. The standard atomic weights and/or the uncertainties of fourteen elements have been changed based on the Atomic Mass Evaluations 2016 and 2020 accomplished under the auspices of the International Union of Pure and Applied Physics (IUPAP). Ar of Ho, Tb, Tm and Y were changed in 2017 and again updated in 2021:
Al (aluminium), 2017: from 26.981 5385 ± 0.000 0007 to 26.981 5384 ± 0.000 0003
Au (gold), 2017: from 196.966 569 ± 0.000 005 to 196.966 570 ± 0.000 004
Co (cobalt), 2017: from 58.933 194 ± 0.000 004 to 58.933 194 ± 0.000 003
F (fluorine), 2021: from 18.998 403 163 ± 0.000 000 006 to 18.998 403 162 ± 0.000 000 005
(Ho (holmium), 2017: from 164.930 33 ± 0.000 02 to 164.930 328 ± 0.000 007)
Ho (holmium), 2021: from 164.930 328 ± 0.000 007 to 164.930 329 ± 0.000 005
Mn (manganese), 2017: from 54.938 044 ± 0.000 003 to 54.938 043 ± 0.000 002
Nb (niobium), 2017: from 92.906 37 ± 0.000 02 to 92.906 37 ± 0.000 01
Pa (protactinium), 2017: from 231.035 88 ± 0.000 02 to 231.035 88 ± 0.000 01
Pr (praseodymium), 2017: from 140.907 66 ± 0.000 02 to 140.907 66 ± 0.000 01
Rh (rhodium), 2017: from 102.905 50 ± 0.000 02 to 102.905 49 ± 0.000 02
Sc (scandium), 2021: from 44.955 908 ± 0.000 005 to 44.955 907 ± 0.000 004
(Tb (terbium), 2017: from 158.925 35 ± 0.000 02 to 158.925 354 ± 0.000 008)
Tb (terbium), 2021: from 158.925 354 ± 0.000 008 to 158.925 354 ± 0.000 007
(Tm (thulium), 2017: from 168.934 22 ± 0.000 02 to 168.934 218 ± 0.000 006)
Tm (thulium), 2021: from 168.934 218 ± 0.000 006 to 168.934 219 ± 0.000 005
(Y (yttrium), 2017: from 88.905 84 ± 0.000 02 to 88.905 84 ± 0.000 01)
Y (yttrium), 2021: from 88.905 84 ± 0.000 01 to 88.905 838 ± 0.000 002
KW - Argon
KW - Ciaaw.org
KW - Hafnium
KW - Iridium
KW - Lead
KW - LSVEC
KW - Ytterbium
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548443
DO - https://doi.org/10.1515/pac-2019-0603
SN - 0033-4545
VL - 94
IS - 5
SP - 573
EP - 600
PB - De Gruyter Verlag
CY - Berlin
AN - OPUS4-54844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shapovalov, O.
A1 - Heckel, Thomas
A1 - Gaal, Mate
A1 - Weiß, S.
T1 - External Acoustical Damping on a Metallic Angle Wedge in a High Temperature Resistant Ultrasonic Probe
N2 - Ultrasonic probes for high-temperature applications are provided with metallic wedges, which can withstand the contact with the high temperature of the inspected structure. The ultrasonic signal travels within the wedge and gets reflected from its boundaries, causing interference signals called “ghost echoes”. The current work presents an investigation of the additional damping effect provided by porous sintered metal plates applied onto the surface of the wedge. In particular, the study evaluates the effect of damping plate thickness on the interference signal level at different transmission frequencies. Damping plates made of sintered metal SIKA-R 15 AX were attached to a wedge prototype made of steel 1.4301. The study revealed, that the most effective thickness of damping plates in the selected frequency interval of 1 to 4 MHz is equal to 4 mm. The evaluation of the interference signal has shown that the application of such damping plates to the wedge surface contributes to an additional attenuation of an interference signal of 10 to 30 dB after 500 μs of signal propagation.
KW - Ultrasonic testing
KW - High temperature
KW - Acoustical damping
KW - Angle wedge
KW - Ultrasonic probe
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553920
DO - https://doi.org/10.1007/s40857-022-00270-9
SN - 0814-6039
SP - 1
EP - 11
PB - Springer
AN - OPUS4-55392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Bethke, John
A1 - Vogler, Nico
A1 - Goedecke, Thomas
T1 - Flow properties of powdery or granular filling substances of dangerous goods packagings - Comparison of the measurement of the angle of repose and the determination of the Hausner ratio
N2 - To ensure safety when transporting dangerous goods, it is important to specify the flow properties of the respective solid filling substance of the packagings. For this purpose, the angle of repose is currently used for the UN approvals in Germany. Measurements were carried out on 12 powdery or granular substances applying the angle of repose measuring methods customary in the test centres. The results of the methods differ significantly from each other. In addition, some of the techniques cannot be applied for very cohesive or coarse-grained materials. The results for the angle of repose show a strong scatter for some constellations (coefficient of variation more than 20 %). Safety during transport of dangerous goods cannot be guaranteed with this currently practiced system of measuring the angle of repose. As a consequence, an alternative parameter to characterize the flow properties of bulk materials should be used in the recognized test centers for dangerous goods packagings, such as the Hausner ratio. This approach leads to more precise test results for the substances examined (maximum coefficient of variation 2.8 %). It also has advantages in terms of applicability and occupational safety.
Since the flow properties are safety-relevant, both in terms of mechanical safety and safety against the release of dangerous substances, the testing practice in the recognized test labs should be improved and standardized.
KW - Sift-proofness
KW - Powders
KW - Flowability
KW - Flow properties
KW - Angle of repose
KW - Hausner ratio
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552990
DO - https://doi.org/10.1002/pts.2678
SP - 1
EP - 18
PB - Wiley online library
AN - OPUS4-55299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gupta, P.
A1 - Karnaushenko, D. D.
A1 - Becker, C.
A1 - Okur, I. E.
A1 - Melzer, Michael
A1 - Özer, B.
A1 - Schmidt, O. G.
A1 - Karnaushenko, D.
T1 - Large Scale Exchange Coupled Metallic Multilayers by Roll-to-Roll (R2R) Process for Advanced Printed Magnetoelectronics
N2 - Till now application of printed magnetoelectronics is hindered by lack of large area exchange coupled metallic multilayers required to produce printable magneto-sensory inks. Large-scale roll-to-roll (R2R) fabrication process is an attractive approach owing to its capabilities for high volume, high throughput, and large area manufacturing. Precise and high performance R2R sputtering technology is developed to fabricate large area giant magnetoresistive (GMR) thin-films stacks that contain 30 metallic bilayers prepared by continuous R2R sputtering of Co and Cu sequential on a hundred meters long polyethylene terephthalate (PET) web. The R2R sputtered Co/Cu multilayer on a 0.2 × 100 m2 PET web exhibits a GMR ratio of ≈40% achieving the largest area exchange coupled room temperature magneto-sensitive system demonstrated to date. The prepared GMR thin-film is converted to magnetosensitive ink that enables printing of magnetic sensors with high performance in a cost-efficient way, which promotes integration with printed electronics. An average GMR ratio of ≈18% is obtained for 370 printed magnetic sensors. The realized precise R2R sputtering approach can also be extended to a wide range of hybrid thin-film material systems opening up a path for new functional inks applied with printing technologies.
KW - Printed Electronics
KW - Flexible Magnetic Sensors
KW - Roll-to-Roll Processing
KW - Functional Materials
KW - Upscaling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552344
DO - https://doi.org/10.1002/admt.202200190
SN - 2365-709X
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim, Deutschland
AN - OPUS4-55234
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Bernhardt, Y.
A1 - Csaszar, L.
A1 - Dengiz, N.
A1 - Fuchs, M.
A1 - Gautzsch, T.
A1 - Gohlke, Dirk
A1 - Hahn-Jose, T.
A1 - Heckel, Thomas
A1 - Hillger, W.
A1 - Hufschläger, Daniel
A1 - Ilse, D.
A1 - Kiel, M.
A1 - Labud, P.
A1 - Schubert, F.
A1 - Sommerhuber, R.
A1 - Szewieczek, A.
A1 - Waschkies, T.
T1 - Richtlinie zur Charakterisierung von luftgekoppelten Ultraschallwandlern
N2 - Zur Charakterisierung von luftgekoppelten Ultraschallwandlern werden mehrere verschiedene Methoden und Verfahren angewendet. Durch die unterschiedlichen Herangehensweisen werden oft unterschiedliche Prüfkopfpara-meter und Schallfeldgrößen ermittelt, was einen direkten Vergleich von Datenblättern erschwert. Für die Charakterisierung von Kontakt- und Tauchtechnikprüfköpfen hat sich ISO 22232-2:2021 bereits etabliert, allerdings ist diese Norm nicht auf die luftgekoppelten Wandlertechnologien direkt übertragbar. Daher erkannten Hersteller, Forschungseinrichtungen und Anwender den Bedarf an einer Richtlinie zur einheitlichen Charakterisierung von luftgekoppelten Wandlern. Gemeinsam arbeiten sie aktuell im Rahmen des Unterausschusses „Luftgekoppelte Ultraschallprüfung“ der DGZfP an der Erstellung einer solcher Richtlinie mit dem Anspruch, die bestehende Normung um die luftgekoppelte Prüfung zu erweitern und somit die Vereinheitlichung der Charakterisierung dieser Wandler zu erleichtern.
In diesem Beitrag wird ein Überblick über den geplanten Inhalt der Richtlinie und über die Methoden zur akustischen Charakterisierung von luftgekoppelten Ultraschallwandlern gegeben. Insbesondere werden verschiedene Methoden der Ermittlung von wichtigen Wandlerparametern wie z.B. Empfindlichkeit, Mittenfrequenz, Bandbreite, Fokusgröße und Fokusabstand dargestellt und verglichen.
T2 - DGZfP-Jahrestagung
CY - Kassel, Germany
DA - 23.05.2022
KW - Lutgekoppelte Ultraschallprüfung
KW - Prüfkopf
KW - Charakterisierung
KW - Richtlinie
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552918
SP - 1
EP - 7
AN - OPUS4-55291
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von der Au, Marcus
A1 - Faßbender, Sebastian
A1 - Chronakis, Michail
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Size determination of nanoparticles by ICP-ToF-MS using isotope dilution in microdroplets
N2 - Within this work, the combination of a microdroplet generator and an ICP-ToF-MS for nanoparticle analysis is presented. For the size determination of platinum nanoparticles an on-line isotope dilution analysis approach was developed. The 194Pt/195Pt isotopic ratio was used for the characterization of the particles, while the 182W/183W isotopic ratio was monitored simultaneously for mass bias correction. The on-line ID-MDG-sp-ICP-ToF-MS approach was deployed for the size determination of three platinum nanoparticle samples (50 nm, 63 nm, 70 nm); for validation, complementary size characterization techniques (sp-ICP-ToF-MS and TEM) were used. The robustness of this technique was evidenced, by using sodium chloride concentrations up to 100 mg L−1 as a matrix component. Our new on-line ID MDG-sp-ICP-ToF-MS approach is a promising tool for the fast and reliable determination of nanoparticles' size in severe matrix concentrations, e.g., environmental samples.
KW - ICP-ToF-MS
KW - Nanoparticles
KW - Isotope Dilution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552727
DO - https://doi.org/10.1039/D2JA00072E
SN - 0267-9477
VL - 37
IS - 6
SP - 1203
EP - 1207
PB - Royal Society of Chemistry
AN - OPUS4-55272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Abis, M.
A1 - Bruno, M.
A1 - Simon, Franz-Georg
A1 - Grönhom, R.
A1 - Kuchta, K.
A1 - Fiore, S.
ED - Medici, F.
T1 - A Novel Dry Treatment for Municipal Solid Waste Incineration Bottom Ash for the Reduction of Salts and Potential Toxic Elements
N2 - The main obstacle to bottom ash (BA) being used as a recycling aggregate is the content of salts and potential toxic elements (PTEs), concentrated in a layer that coats BA particles. This work presents a dry treatment for the removal of salts and PTEs from BA particles. Two pilotscale abrasion units (with/without the removal of the fine particles) were fed with different BA samples. The performance of the abrasion tests was assessed through the analyses of particle size and moisture, and that of the column leaching tests at solid-to-liquid ratios between 0.3 and 4. The results were: the particle-size distribution of the treated materials was homogeneous (25 wt % had dimensions <6.3 mm) and their moisture halved, as well as the electrical conductivity of the leachates. A significant decrease was observed in the leachates of the treated BA for sulphates (44%),
chlorides (26%), and PTEs (53% Cr, 60% Cu and 8% Mo). The statistical analysis revealed good correlations between chloride and sulphate concentrations in the leachates with Ba, Cu, Mo, and Sr, illustrating the consistent behavior of the major and minor components of the layer surrounding BA particles. In conclusion, the tested process could be considered as promising for the improvement of BA valorization.
KW - Bottom ash
KW - Dry treatment
KW - Municipal solid waste
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552161
SN - 978-3-0365-3063-5
DO - https://doi.org/10.3390/ma14113133
SP - 57
EP - 71
PB - MDPI
CY - Basel
AN - OPUS4-55216
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
A1 - Heckel, Thomas
A1 - Prager, Jens
A1 - Berendt, T.
A1 - Voehringer, D.
T1 - Robotergeführte Ultraschallprüfung von Gasturbinenschaufeln mit adaptiver TFM im ZfP 4.0-Umfeld
N2 - Leit- und Laufschaufeln stationärer Gasturbinen sind im Betrieb anspruchsvollen Bedingungen ausgesetzt. Die Prüfung, Wartung und Reparatur der hochbelasteten Teile sind notwendig, um Sicherheit und Effizienz über längere Zeiträume zu gewährleisten. Eine der in diesem Prozess angewandten Methoden ist die Ultraschallprüfung.
Im Zuge der fortschreitenden Digitalisierung ist es das Ziel des Projektes MRO 2.0, den Aufbereitungsvorgang um digitale Prozesse zu erweitern und somit zu modernisieren. Eine der Aufgaben ist es, dabei anstelle der konventionellen Ultraschallprüfung eine Array-Technik mit rekonstruierenden Verfahren einzusetzen und eine automatisierte, digital eingebundene Methode im Rahmen von ZfP 4.0 zu entwickeln.
Um die Ist-Geometrie der Oberfläche und die verbleibende Wanddicke flächendeckend an den Turbinenschaufeln zu bestimmen, wird ein adaptives TFM Verfahren (Total Focusing Method) in Tauchtechnik eingesetzt, welches die Brechung der Schallwellen an der Grenzfläche zum Prüfkörper in der Rekonstruktion berücksichtigt. In der hierfür entwickelten Prüfanlage führt ein Roboterarm einen Array-Prüfkopf und scannt das Bauteil normal zur inspizierten Oberfläche. Somit kann ein 3D-Modell des Ist Zustandes des zu prüfenden Bauteils erstellt werden.
Spezielle Herausforderungen an die Aufgabe stellen die komplexe Geometrie des Prüfobjektes sowie dessen geringe und ortsabhängige Wanddicke dar. Ein weiterer Fokus liegt auf der Optimierung der Prüfparameter, Verbesserung der Prüfgeschwindigkeit sowie der Zuverlässigkeit der Methode.
In diesem Beitrag werden die während des Projektes entwickelte Methode und die im zweiten Projektjahr erarbeiteten Ergebnisse vorgestellt, mit dem Schwerpunkt auf die entwickelten Rekonstruktionsalgorithmen und den Versuchsaufbau.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Ultraschallprüfung
KW - Turbinenschaufel
KW - Phased Array
KW - Total Focusing Method
KW - Automatisierung
KW - Tauchtechnik
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551881
UR - https://www.ndt.net/search/docs.php3?id=27055
SP - 1
EP - 11
PB - NDT.net
AN - OPUS4-55188
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schnur, C.
A1 - Goodarzi, P.
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Prager, Jens
A1 - Tschöke, K.
A1 - Moll, J.
A1 - Schütze, A.
A1 - Schneider, T.
T1 - Towards interpretable machine learning for automated damage detection based on ultrasonic guided waves
N2 - Data-driven analysis for damage assessment has a large potential in structural health monitoring (SHM) systems, where sensors are permanently attached to the structure, enabling continuous and frequent measurements. In this contribution, we propose a machine learning (ML) approach for automated damage detection, based on an ML toolbox for industrial condition monitoring. The toolbox combines multiple complementary algorithms for feature extraction and selection and automatically chooses the best combination of methods for the dataset at hand. Here, this toolbox is applied to a guided wave-based SHM dataset for varying temperatures and damage locations, which is freely available on the Open Guided Waves platform. A classification rate of 96.2% is achieved, demonstrating reliable and automated damage detection. Moreover, the ability of the ML model to identify a damaged structure at untrained damage locations and temperatures is demonstrated.
KW - Composite structures
KW - Structural health monitoring
KW - Carbon fibre-reinforced plastic
KW - Interpretable machine learning
KW - Automotive industry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542060
DO - https://doi.org/10.3390/s22010406
SN - 1424-8220
VL - 22
IS - 1
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-54206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mellios, N.
A1 - Oesch, Tyler
A1 - Spyridis, P.
T1 - Finite element modelling of UHPC under pulsating load using X-ray computed tomography based fiber distributions
N2 - The benefits of including fibers in ultra-high performance concrete (UHPC) are attributed to their good bond with the matrix and, hence, an optimal utilization of their properties. At the same time, though, fiber reinforcement may contribute to anisotropy in the composite material and induce weak areas. The influence of the fibers’ orientation on the material properties is a matter of current scientific discourse and it is known to play a vital role in structural design. In the case studies presented herein, mechanical laboratory tests using pulsating load regimes on UHPC with a strength of more than 200 MPa were simulated by use of finite element models. The orientations of the fibers were measured for each test sample prior to failure using an X-ray computed tomography (CT) scanner, and these orientations are explicitly implemented into the model. The paper discusses the methodology of merging data retrieved by CT image processing and state-of-the-art FE simulation techniques Moreover, the CT scanning was carried out throughout the testing procedure, which further enables the comparison of the mechanical tests and the FE models in terms of damage propagation and failure patterns. The results indicate that the overall fiber configuration and behavior of the samples can be realistically modelled and validated by the proposed CT-FE coupling, which can enhance the structural analysis and design process of elements produced with steel fiber reinforced and UHPC materials.
KW - Ultra-high performance concrete
KW - Steel fiber reinforced concrete
KW - Fiber orientation
KW - X-ray computed tomography
KW - Non-linear finite element modelling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542105
DO - https://doi.org/10.1617/s11527-021-01833-4
SN - 1871-6873
VL - 55
IS - 1
SP - 1
EP - 20
PB - Springer
CY - Dordrecht
AN - OPUS4-54210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Different types of continuous track irregularities as sources of train-induced ground vibration and the importance of the random variation of the track support
N2 - Irregularities of the track are a main cause of train-induced ground vibration, and track maintenance is of great importance. Although geometric irregularities at the wheel-rail contact are widely used, other types of irregularities, such as stiffness irregularities, irregularities from different track positions and irregularities in the wave propagation, were analysed in the present study. The track behaviour was investigated by a multi-beam-on-soil model. This track model is coupled with a vehicle model to calculate the vehicle–track interaction. The track model was also used for the track filtering, which transfers a track support error to the equivalent rail irregularity or, conversely, the sharp axle pulse on the rail to a smoother pulse on the soil. In the case in which this filtering varies randomly along the track, the pulses of the moving static load induce a certain ground Vibration component (“the scatter of axle pulses”). This effect was calculated by the superposition of axle pulses in the frequency domain and by a stochastic simulation. Simultaneous vehicle, track and soil measurements at a certain site were used to evaluate the different excitation and ground Vibration components. The agreement between calculations and axle-box and soil measurements is good. The ground vibrations calculated from rail irregularities and corresponding dynamic loads, however, clearly underestimate the measured ground vibration amplitudes. Only the static load that is moving over a varying track support stiffness can produce the important mid-frequency ground Vibration component by the scatter of axle pulses.
KW - Train-induced ground vibration
KW - Geometric vehicle and track irregularities
KW - Stiffness variation
KW - Multi-beam track model
KW - Track filtering
KW - Dynamic axle loads
KW - Static axle loads
KW - layered soil
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543846
DO - https://doi.org/10.3390/app12031463
SN - 2076-3417
VL - 12
IS - 3
SP - 1
EP - 22
PB - MDPI
CY - Basel
AN - OPUS4-54384
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Phase error analysis and unwrapping error suppression in phase-sensitive optical time domain reflectometry
N2 - Phase-sensitive optical time domain reflectometry becomes an effective tool to realize distributed sensing, and the optical phase of the received light is usually used to quantify the strain for both dynamic and static measurement. The analysis on the overall phase error has been improved by considering the proportionality of the detection noise to the local optical power. The estimation accuracy is greatly improved by using the proposed theory, the probability density of the estimation accuracy over 99% is > 0.6, ∼39 times larger than the previously reported method. The phase unwrapping may malfunction due to the noisy signal, causing large phase errors. Point break detection algorithms are used to locate the incorrect phase unwrapping points, so the temporal evolution of the phase retrieved at each position can be divided into several sections with different offset. The phase unwrapping error is then suppressed by removing the offset.
KW - Phase unwrapping
KW - Distributed fiber sensing
KW - Acoustic sensing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543919
DO - https://doi.org/10.1364/OE.446517
VL - 30
IS - 5
SP - 6934
EP - 6948
PB - Optica Publishing Group
AN - OPUS4-54391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krankenhagen, Rainer
A1 - Zirker, Stefan
A1 - Joniertz, Florian
T1 - Determination of thermal parameters of concrete by active thermographic measurements
N2 - The knowledge of the thermal parameters of a particular concrete is essential for thermal design of a building, but also could help to identify and assess the state of a concrete structure. Active thermography has the potential to be applied onsite and to provide a fast investigation of thermal properties. In this work, three different concrete samples were investigated by active thermography in reflection and in transmission setup. It was found that this method yields the same results without direct contact as the Transient Plane Source (TPS) method as an established inspection tool.
KW - Concrete
KW - Effusivity
KW - Thermal diffusivity
KW - Photothermal
KW - Thermography
KW - Hot disc method
KW - Parker method
KW - Onsite inspection
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543781
DO - https://doi.org/10.1007/s10921-022-00861-6
SN - 0195-9298
SN - 1573-4862
VL - 41
IS - 1
SP - 1
EP - 20
PB - Springer
AN - OPUS4-54378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fulawka, K.
A1 - Kwietniak, A.
A1 - Lay, Vera
A1 - Jaskiewicz-Proc, I.
T1 - Importance of seismic wave frequency in FEM-based dynamic stress and displacement calculations of the earth slope
N2 - Reliable assessment of earthen dams’ stability and tailing storage facilities widely used in the mining industry is challenging, particularly under seismic load conditions. In this paper, we propose to take into account the effect of the dominant frequency of seismic load on the stability assessment of tailing/earthen dams. The calculations are performed by finite element modelling (FEM) with the Mohr–Coulomb failure criteria. To separate the frequency content from other dynamic parameters describing the seismic wave, synthetic waveforms with identical amplitude and attenuation characteristics, but differing spectral characteristics have been used. The analysis has been performed for three different slope angles and two scenarios of seismic wave propagation. Consequently, the changes of total displacement and shear stresses depending on the frequencies have been determined and clearly show that lower frequencies cause higher stress levels and displacement. Finally, the response surface methodology has been applied to determine how different parameters affect the slope stability under dynamic load conditions. Overall, this study is a first step to improve the existing methods to assess slope stability when considering seismic load.
KW - Slope stability
KW - Numerical analysis
KW - Seismic load
KW - Frequency analysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544047
DO - https://doi.org/10.2478/sgem-2022-0002
SN - 2083-831X
VL - 44
IS - 1
SP - 82
EP - 96
PB - De Gruyter
CY - Berlin
AN - OPUS4-54404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, F.
A1 - Dyall-Smith, M.
A1 - Kunte, Hans-Jörg
T1 - Genome Sequence of Micromonospora aurantiaca Strain G9, a Member of a Bacterial Consortium Capable of Polyethylene Degradation
N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G9 was determined by PacBio sequencing. Using the TYGS server for taxonomic classification, strain G9 was assigned to the species Micromonospora aurantiaca.
KW - Polyethylene
KW - Micromonospora aurantiaca
KW - Degradation
KW - iChip
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547181
DO - https://doi.org/10.1128/mra.01148-21
SN - 2576-098X
VL - 11
IS - 5
SP - 1
EP - 2
PB - American Society for Microbiology
CY - Washington, DC
AN - OPUS4-54718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hübler, Daniela
A1 - Gradt, Thomas
T1 - Effect of different binders and secondary carbides on NbC cermets
T1 - Einfluss unterschiedlicher Binder und Sekundärkarbide auf NbC-Hartmetalle
N2 - Due to the rapidly increasing price of tungsten carbide and the significant health risks associated with the wear products of WC-Co (Co3O4 and Wo3), an alternative is required. Niobium carbide (NbC) is well suited as a cutting tool due to its high melting point and low solubility in iron. So far, NbC-Ni cermets best met the requirements of high hardness and toughness. Various secondary carbides such as VC, Mo2C, TiC, but also WC were added to further improve the hardness.
N2 - Aufgrund des rasanten Preisanstiegs von Wolframcarbid und signifikanter Gesundheitsrisiken, die mit den Verschleißprodukten von WC-Co-Hartmetallen (Co3O4 and Wo3) einhergehen, wird eine Alternative benötigt. Niobcarbid (NbC) ist als Zerspanwerkzeug aufgrund seiner hohen Schmelztemperatur und seiner geringen Löslichkeit in Eisen gut geeignet. Im Vergleich zu reinem NbC, führte eine vollständige Substitution von WC zu NbC-Co zu einem Anstieg der Zähigkeit und Festigkeit. Als alternative Binder wurden anschließend Nickel- und Eisengebundene Binder untersucht. Obwohl eisengebundene Hartmetalle im Vergleich zu NbC-Ni Hartmetallen eine ökonomische und kostengünstigere Alternative darstellen würden, zeigten sie einen höheren Reibkoeffizienten und eine höhere Verschleißrate. Bisher erfüllen die NbC-Ni-Hartmetalle die Anforderungen hinsichtlich einer hohen Härte und Zähigkeit am besten. Verschiedene Sekundärkarbide, wie VC, Mo2C, TiC, aber auch WC wurden zusätzlich hinzugefügt, um die Härte weiter zu steigern. Elementanalysen der NbC-Ni-MeC Hartmetalle (Me = Metall) zeigten, dass der Binder eine kubisch-flächenzentrierter Mischkristall ist, während die NbC Phase ein Mischkristall des Typs (Nb, Me)C ist.
KW - Niobium carbide (NbC)
KW - Cutting tool
KW - Binders
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547202
DO - https://doi.org/10.1007/s10010-022-00583-1
SN - 0015-7899
VL - 86
IS - 2
SP - 197
EP - 211
PB - Springer
CY - Berlin
AN - OPUS4-54720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altenburg, T.
A1 - Giese, S.
A1 - Wang, S.
A1 - Muth, Thilo
A1 - Renard, B.Y.
T1 - Ad hoc learning of peptide fragmentation from mass spectra enables an interpretable detection of phosphorylated and cross-linked peptides
N2 - Mass spectrometry-based proteomics provides a holistic snapshot of the entire protein set of living cells on a molecular level. Currently, only a few deep learning approaches exist that involve peptide fragmentation spectra, which represent partial sequence information of proteins. Commonly, these approaches lack the ability to characterize less studied or even unknown patterns in spectra because of their use of explicit domain knowledge. Here, to elevate unrestricted learning from spectra, we introduce ‘ad hoc learning of fragmentation’ (AHLF), a deep learning model that is end-to-end trained on 19.2 million spectra from several phosphoproteomic datasets. AHLF is interpretable, and we show that peak-level feature importance values and pairwise interactions between peaks are in line with corresponding peptide fragments. We demonstrate our approach by detecting post-translational modifications, specifically protein phosphorylation based on only the fragmentation spectrum without a database search. AHLF increases the area under the receiver operating characteristic curve (AUC) by an average of 9.4% on recent phosphoproteomic data compared with the current state of the art on this task. Furthermore, use of AHLF in rescoring search results increases the number of phosphopeptide identifications by a margin of up to 15.1% at a constant false discovery rate. To show the broad applicability of AHLF, we use transfer learning to also detect cross-linked peptides, as used in protein structure analysis, with an AUC of up to 94%.
KW - Mass spectrometry
KW - Machine learning
KW - Deep learning
KW - Peptide identification
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547580
DO - https://doi.org/10.1038/s42256-022-00467-7
SN - 2522-5839
VL - 4
SP - 378
EP - 388
PB - Springer Nature
CY - London
AN - OPUS4-54758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Veico, V. P.
A1 - Karlagina, Yu. Yu.
A1 - Samokhvalov, A. A.
A1 - Polyakov, D. S.
A1 - Manokhin, S. S.
A1 - Radaev, M. M.
A1 - Odintsova, G. V.
A1 - Gornushkin, Igor B.
T1 - Surface Structuring and Reverse Deposition of Nanoporous Titanium Oxides by Laser Ablation of Titanium in Air
N2 - The deposition of titanium oxides during titanium laser ablation in air has been experimentally and numerically investigated. A titanium sample was irradiated by nanosecond pulses from an Yb-fber laser with a beam scanned across the sample surface for its texturing. As a result, the hierarchical structure was observed consisting of a microrelief formed by the laser ablation and a nanoporous coating formed by the reverse deposition from the laser induced plasma plume. The chemical and phase composition of the nanoporous coating, as well as the morphology and structure of the surface, were studied using scanning electron microscopy, atomic force microscopy, and X-ray microanalysis. It was found that the deposit consists mostly of porous TiO2 with 26% porosity and inclusions of TiO, Ti2O3, and Ti2O3N. Optical emission spectroscopy was used to control the plasma composition and estimate the effective temperature of plasma plume. The chemical-hydrodynamic model of laser induced plasma was developed to get a deeper insight into the deposition process. The model predicts that condensed titanium oxides, formed in peripheral plasma
zones, gradually accumulate on the surface during the plasma plume evolution. A satisfactory agreement between the experimental and calculated chemical composition of the plasma plume as well as between the experimental and calculated composition and thickness of the deposited film was demonstrated. This allows a cautious conclusion that the formation of condensed oxides in the plasma and their consequent deposition onto the ablation surface are among the key mechanisms of formation of porous surface films.
KW - Laser ablation
KW - Laser induced plasma deposition
KW - Surface coating
KW - Titanium dioxide
KW - Hydrodynamic model
KW - Plasma chemistry
KW - Emission spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548555
DO - https://doi.org/10.1007/s11090-022-10256-0
VL - 42
IS - 4
SP - 923
EP - 937
PB - Springer
AN - OPUS4-54855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amano, K.
A1 - Hahn, S.
A1 - Tschirschwitz, Rico
A1 - Rappsilber, Tim
A1 - Krause, U.
T1 - An Experimental Investigation of Thermal Runaway and Gas Release of NMC Lithium-Ion Pouch Batteries Depending on the State of Charge Level
N2 - In this study, 19 experiments were conducted with 25 pouch cells of NMC cathode to investigate thermal runaway and the release of gases from lithium-ion batteries (LIBs). Single cells, double cells, and a four-cell battery stack were forced to undergo thermal runaway inside an air-tight reactor vessel with a volume of 100 dm3 . The study involved two series of tests with two types of ignition sources. In the Series 1 tests, a heating plug was used to initiate thermal runaway in LIBs in the ranges of 80–89% and 90–100% SOC. In the Series 2 tests, a heating plate was used to trigger thermal runaway in LIBs in the ranges of 30–50%, 80–89%, and 90–100% SOC. Thermal runaway started at an onset temperature of 344 ± 5 K and 345 K for the Series 1 tests and from 393 ± 36 K to 487 ± 10 K for the Series 2 tests. Peak reaction temperatures ranged between 642 K and 1184 K, while the maximum pressures observed were between 1.2 bar and 7.28 bar. Thermal runaway induced explosion of the cells and lead to a rate of temperature increase greater than 10 K/s. The amounts of gases released from the LIBs were calculated from pressures and temperatures measured in the reactor.
Then, the gas composition was analyzed using a Fourier transform infrared (FTIR) spectrometer. The highest gaseous production was achieved at a range of 90–100% SOC and higher battery capacities 72 L, 1.8 L/Ah (Series 1, battery stack) and 103 L, 3.2 L/Ah (Series 2, 32 Ah cell)). Among the gases analyzed, the concentration of gaseous emissions such as C2H4 , CH4 , and C2H6 increased at a higher cell capacity in both series of tests. The study results revealed characteristic variations of thermal behavior with respect to the type of ignition source used.
KW - Lithium-ion batteries
KW - Battery
KW - Pouch cell
KW - NMC Cathode
KW - Thermal runaways
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548601
DO - https://doi.org/10.3390/batteries8050041
VL - 8
IS - 5
SP - 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-54860
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, F.
A1 - Dyall-Smith, M.
A1 - Kunte, Hans-Jörg
T1 - Genome Sequence of Pseudomonas veronii Strain G2, a Member of a Bacterial Consortium Capable of Polyethylene Degradation
N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G2 was determined by PacBio sequencing. Using the TYGS server for taxonomic classification, strain G2 was assigned to the species Pseudomonas veronii.
KW - Polyethylene
KW - Next generation sequencing
KW - Pseudomonas veronii
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548973
DO - https://doi.org/10.1128/mra.00365-22
SP - 1
EP - 2
PB - ASM
AN - OPUS4-54897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Häßler, Dustin
A1 - Hothan, Sascha
T1 - Performance of intumescent fire protection coatings applied to structural steel tension members with circular solid and hollow sections
N2 - Intumescent fire protection coatings are used to improve the fire resistance of steel members. Due to slender cross-sections typically used for tension members, high demands are placed on the effectiveness and reliability of the intumescent coatings. This paper describes real-scale fire tests of intumescent coatings applied to steel tension members with circular solid and hollow sections. First, the current regulations for the application of intumescent coatings on steel tension members are discussed. After that, a comparison between the foaming behaviour and failure mechanisms of intumescent coatings applied to steel tension members with different cross-sections and loading conditions is given. Next, the experimental setup and procedure of the performed fire tests are presented. In addition, the influences of various parameters on the performance of the intumescent coating are analysed, including the geometry of the steel profile, dry film thickness of the intumescent coating, load utilisation level as well as the orientation of the member. Based on the theoretical considerations and results of the fire tests, it is evidenced that mechanically loaded fire tests are essential to assess accurately the contribution of intumescent fire protection coatings to the fire resistance of steel tension members with circular solid sections.
KW - Fire tests
KW - Intumescent coating
KW - Reactive fire protection system
KW - Steel
KW - Tension members
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548981
DO - https://doi.org/10.1016/j.firesaf.2022.103605
SN - 0379-7112
VL - 131
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-54898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cordsmeier, Leo
A1 - Hahn, Marc Benjamin
T1 - DNA Stability in Biodosimetry, Pharmacy and DNA Based Data-Storage: Optimal Storage and Handling Conditions
N2 - DNA long-term stability and integrity is of importance for applications in DNA based bio-dosimetry, data-storage, pharmaceutical quality-control, donor insemination and DNA based functional nanomaterials. Standard protocols for these applications involve repeated freeze-thaw cycles of the DNA, which can cause detrimental damage to the nucleobases, as well as the sugar-phosphate backbone and therefore the whole molecule. Throughout the literature three hypotheses can be found about the underlying mechanisms occurring during freeze-thaw cycles. It is hypothesized that DNA single-strand breaks during freezing can be induced by mechanical stress leading to shearing of the DNA molecule, by acidic pH causing damage through depurination and beta elimination or by the presence of metal ions catalyzing oxidative damage via reactive oxygen species (ROS). Here we test these hypotheses under well defined conditions with plasmid DNA pUC19 in high-purity buffer (1xPBS) at physiological salt and pH 7.4 conditions, under pH 6 and in the presence of metal ions in combination with the radical scavengers DMSO and Ectoine. The results show for the 2686 bp long plasmid DNA, that neither mechanical stress, nor pH 6 lead to degradation during repeated freeze-thaw cycles. In contrast, the presence of metal ions (Fe2+) leads to degradation of DNA via the production of radical species.
KW - DNA
KW - DNA stability
KW - Pharmacy
KW - Reference material
KW - pUC19
KW - Strand break
KW - SSB
KW - Dosimetry
KW - Biodosimetry
KW - Biologisches Dosimeter
KW - DNA Dosimeter
KW - Quality control
KW - Plasmid DNA
KW - DNA data storage
KW - Nucleobase
KW - Base damage
KW - Base loss
KW - DNA degradation
KW - Metal ions
KW - ROS
KW - OH radical
KW - Fenton Reaction
KW - H2O2
KW - DNA based data storage
KW - Freezing
KW - Thawing
KW - Mechanical stress
KW - pH
KW - Beta elimination
KW - Ectoine
KW - Ectoin
KW - THP(B)
KW - Radical scavenger
KW - DMSO
KW - Buffer
KW - lN2
KW - DNA vortexing
KW - AGE
KW - SYBR Gold
KW - Gel electrophoresis
KW - DNA long term storage
KW - DNA reference material
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557148
DO - https://doi.org/10.1002/cbic.202200391
SP - 1
EP - 9
PB - Wiley-VCH GmbH
AN - OPUS4-55714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deumer, J.
A1 - Pauw, Brian Richard
A1 - Marguet, S.
A1 - Skroblin, D.
A1 - Taché, O.
A1 - Krumrey, M.
A1 - Gollwitzer, C.
T1 - Small-angle X-ray scattering: characterization of cubic Au nanoparticles using Debye’s scattering formula
N2 - A versatile software package in the form of a Python extension, named CDEF (computing Debye’s scattering formula for extraordinary form factors), is proposed to calculate approximate scattering profiles of arbitrarily shaped nanoparticles for small-angle X-ray scattering (SAXS). CDEF generates a quasi-randomly distributed point cloud in the desired particle shape and then applies the open-source software DEBYER for efficient evaluation of Debye’s scattering formula to calculate the SAXS pattern (https://github.com/j-from-b/CDEF). If self-correlation of the scattering signal is not omitted, the quasi-random distribution provides faster convergence compared with a true-random distribution of the scatterers, especially at higher momentum transfer. The usage of the software is demonstrated for the evaluation of scattering data of Au nanocubes with rounded edges, which were measured at the four-crystal monochromator beamline of PTB at the synchrotron radiation facility BESSY II in Berlin. The implementation is fast enough to run on a single desktop computer and perform model fits within minutes. The accuracy of the method was analyzed by comparison with analytically known form factors and verified with another implementation, the SPONGE, based on a similar principle with fewer approximations. Additionally, the SPONGE coupled to McSAS3 allows one to retrieve information on the uncertainty of the size distribution using a Monte Carlo uncertainty estimation algorithm.
KW - X-ray scattering
KW - SAXS
KW - Non-spherical nanoparticles
KW - Nanoparticles
KW - Nanomaterials
KW - Debye scattering equation
KW - Simulation
KW - Data fitting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557652
DO - https://doi.org/10.1107/S160057672200499X
VL - 55
IS - Pt 4
SP - 993
EP - 1001
PB - International Union of Crystallography
CY - Chester, England
AN - OPUS4-55765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogl, Jochen
A1 - Rienitz, O.
A1 - Pramann, A.
A1 - Flierl, L.
T1 - Scale Conversion and Uncertainty Calculations in Isotope Delta Measurements
N2 - Isotope ratio applications are on the increase and a major part of which are delta measurements, because they are easier to perform than the determination of absolute isotope ratios while offering lower measurement uncertainties. Delta measurements use artefact-based scales and therefore scale conversions are required due to the lack of the scale defining standards. Such scale conversions often form the basis for comparing data being generated in numerous projects andtherefore need to be as accurate as possible. In practice, users are tempted to apply linear approximations, which are not sufficiently exact, because delta values are defined by nonlinear relationships. The bias of such approximations often is beyond typical measurement uncertainties and its extent can hardly be predicted. Therefore, exact calculations are advised. Here, the exact equations and the bias of the approximations are presented, and calculations are illustrated by real-world examples. Measurement uncertainty is indispensable in this context and therefore, its calculation is described as well for determining delta values but also for scale conversions. Approaches for obtaining a single delta measurement and for repeated measurements are presented. For the latter case, a new approach for calculating the measurement uncertainty is presented, which considers covariances between the isotope ratios.
KW - Delta isotope standard
KW - Delta scale
KW - In-house calibration solution
KW - Isotope ratios
KW - Isotope reference material
KW - Measurement uncertainty
KW - Scale conversion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557254
DO - https://doi.org/10.1111/ggr.12450
SN - 1639-4488
VL - 46
IS - 4
SP - 773
EP - 787
PB - Wiley
AN - OPUS4-55725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gornushkin, Igor B.
A1 - Völker, Tobias
T1 - Intrinsic Performance of Monte Carlo Calibration-Free Algorithm for Laser-Induced Breakdown Spectroscopy
N2 - The performance of the Monte Carlo (MC) algorithm for calibration-free LIBS was studied on the example of a simulated spectrum that mimics a metallurgical slag sample. The underlying model is that of a uniform, isothermal, and stationary plasma in local thermodynamical equilibrium.
Based on the model, the algorithm generates from hundreds of thousands to several millions of simultaneous configurations of plasma parameters and the corresponding number of spectra. The parameters are temperature, plasma size, and concentrations of species. They are iterated until a cost function, which indicates a difference between synthetic and simulated slag spectra, reaches its minimum. After finding the minimum, the concentrations of species are read from the model and compared to the certified values. The algorithm is parallelized on a graphical processing unit (GPU) to reduce computational time. The minimization of the cost function takes several minutes on the GPU NVIDIA Tesla K40 card and depends on the number of elements to be iterated. The intrinsic accuracy of the MC calibration-free method is found to be around 1% for the eight elements tested. For a real experimental spectrum, however, the efficiency may turn out to be worse due to the idealistic nature of the model, as well as incorrectly chosen experimental conditions. Factors influencing the performance of the method are discussed.
KW - Laser induced breakdown spectroscopy
KW - Calibration-free analysis
KW - Monte Carlo algorithm
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558016
DO - https://doi.org/10.3390/s22197149
VL - 22
IS - 19
SP - 7149
PB - MDPI
AN - OPUS4-55801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Tobias
A1 - Gornushkin, Igor B.
T1 - Importance of physical units in the Boltzmann plot method
N2 - The Boltzmann plot is one of the most widely used methods for determining the temperature in different types of laboratory plasmas. It operates on the logarithm as a function of the dimensional argument, which assumes that the correct physical units are used. In many works using the Boltzmann method, there is no analysis of the dimension of this argument, which may be the cause of a potential error. This technical note offers a brief description of the method and shows how to correctly use physical units when using transcendental functions like the logarithm.
KW - Boltzmann plot
KW - Laser induced plasma
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558039
DO - https://doi.org/10.1039/d2ja00241h
SP - 1
EP - 3
PB - Royal Society of Chemistry
AN - OPUS4-55803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, F.
A1 - Dyall-Smith, M.
A1 - Kunte, Hans-Jörg
T1 - Genome Sequence of Cupriavidus campinensis Strain G5, a Member of a Bacterial Consortium Capable of Polyethylene Degradation
N2 - Nine different bacterial isolates were recovered from landfills. Each isolate was obtained in pure culture. As a consortium, the bacteria degrade polyethylene. The complete genome sequence of strain G5 was determined by PacBio sequencing. Using the TYGS for taxonomic classification, strain G5 was assigned to the species Cupriavidus campinensis.
KW - Polyethylene
KW - Cupriavidus campinensis
KW - Plastic degradation
KW - Genome sequence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557897
DO - https://doi.org/10.1128/mra.00553-22
SP - 1
EP - 2
PB - ASM
AN - OPUS4-55789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lengas, Nikolaos
A1 - Schlick-Hasper, Eva
A1 - Müller, Karsten
A1 - Neitsch, Marcel
A1 - Johann, Sergej
A1 - Zehn, M.
T1 - Development of an analysis and testing concept for the evaluation of impact targets in the mechanical safety testing of dangerous goods packagings
N2 - The mechanical and geometrical properties of impact targets greatly influence the outcome of a drop test. The International Agreement concerning the International Carriage of Dangerous Goods by Road (ADR) as well as ISO 2248 describe the characteristics of impact targets for drop tests of dangerous goods packagings.
According to these regulations, the impact target’s surface needs to be unyielding, under testing conditions non-deformable, flat, and integral with a mass at least 50 times that of the heaviest packaging to be tested. The problem is that many production facilities, especially manufacturers of corrugated fibreboard boxes, do not have their own testing device with the required 50 times mass ratio of the impact target for a regulation compliant drop test during series production. Furthermore, at UN level it is considered necessary to revise these requirements.
In the present paper, the impact target requirements are examined in detail and compared with those in other technical areas (e.g., impact target for container for the transport of radioactive materials). A research method is being developed to investigate the dependency between the mass ratio of the packaging and the target as well as the damage resistance of a drop tested package in relation to specific design characteristics. The results are of high relevance for industry purposes and intended to ensure a uniform level of safety assessment for the mechanical testing of dangerous goods packagings.
KW - Corrugated fibreboard boxes
KW - Dangerous goods packagings
KW - Drop test
KW - Impact target
KW - Structural dynamics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549660
DO - https://doi.org/10.1002/pts.2656
SN - 0894-3214
SN - 1099-1522
VL - 35
IS - 9
SP - 689
EP - 700
PB - Wiley
CY - New York, NY
AN - OPUS4-54966
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spallanzani, Roberta
A1 - Koga, K.
A1 - Cichy, S.
A1 - Wiedenbeck, M.
A1 - Schmidt, B.
A1 - Oelze, Marcus
A1 - Wilke, M.
T1 - Lithium and boron difusivity and isotopic fractionation in hydrated rhyolitic melts
N2 - Lithium and boron are trace components of magmas, released during exsolution of a gas phase during volcanic activity. In this study, we determine the difusivity and isotopic fractionation of Li and B in hydrous silicate melts. Two glasses were synthesized with the same rhyolitic composition (4.2 wt% water), having diferent Li and B contents; these were studied in difusion-couple experiments that were performed using an internally heated pressure vessel, operated at 300 MPa in the temperature range 700–1250 °C for durations from 0 s to 24 h. From this we determined activation energies for Li and B difusion of 57±4 kJ/mol and 152±15 kJ/mol with pre-exponential factors of 1.53 × 10–7 m2/s and 3.80× 10–8 m2 /s, respectively. Lithium isotopic fractionation during difusion gave β values between 0.15 and 0.20, whereas B showed no clear isotopic fractionation. Our Li difusivities and isotopic fractionation results difer somewhat from earlier published values, but overall confrm that Li difusivity increases with water content. Our results on B difusion show that similarly to Li, B mobility increases in the presence of water. By applying the Eyring relation, we confrm that B difusivity is limited by viscous fow in silicate melts. Our results on Li and B difusion present a new tool for understanding degassing-related processes, ofering a potential geospeedometer to measure volcanic ascent rates.
KW - Hydrated silicate melts
KW - Stable isotopes
KW - Diffusion
KW - Isotopic fractionation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554496
DO - https://doi.org/10.1007/s00410-022-01937-2
VL - 177
IS - 8
SP - 1
EP - 17
PB - Springer
AN - OPUS4-55449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hauffen, J. C.
A1 - Kästner, L.
A1 - Ahmadi, Samim
A1 - Jung, P.
A1 - Caire, G.
A1 - Ziegler, Mathias
T1 - Learned block iterative shrinkage thresholding algorithm for photothermal super resolution imaging
N2 - Block-sparse regularization is already well known in active thermal imaging and is used for multiple-measurement-based inverse problems. The main bottleneck of this method is the choice of regularization parameters which differs for each experiment. We show the benefits of using a learned block iterative shrinkage thresholding algorithm (LBISTA) that is able to learn the choice of regularization parameters, without the need to manually select them. In addition, LBISTA enables the determination of a suitable weight matrix to solve the underlying inverse problem. Therefore, in this paper we present LBISTA and compare it with state-of-the-art block iterative shrinkage thresholding using synthetically generated and experimental test data from active thermography for defect reconstruction. Our results show that the use of the learned block-sparse optimization approach provides smaller normalized mean square errors for a small fixed number of iterations. Thus, this allows us to improve the convergence speed and only needs a few iterations to generate accurate defect reconstruction in photothermal super-resolution imaging.
KW - Thermography
KW - Laser
KW - Machine learning
KW - Optimization
KW - Non-destructive testing
KW - NDT
KW - Neural network
KW - Defect reconstruction
KW - Block-sparsity
KW - Active thermal imaging
KW - Regularization
KW - Laser thermography
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554598
DO - https://doi.org/10.3390/s22155533
SN - 1424-8220
VL - 22
IS - 15
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-55459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mehri, S.
A1 - Kolmangadi, Mohamed Aejaz
A1 - Dyre, J.C.
A1 - Ingebrigtsen, T.S.
T1 - Lines of invariant physics in the isotropic phase of the discotic Gay-Berne model
N2 - The Gay-Berne model is studied numerically with a choice of parameters allowing for the formation of a discotic liquid crystal at low temperatures. We show that the model has strong virial potential-energy correlations in the isotropic phase at high temperatures, i.e., it obeys the criterion for the existence of isomorphs, which are curves of approximately invariant structure and dynamics. These properties are demonstrated to be approximately invariant in reduced units along the isomorph studied. The isomorph is described well by the constant density-scaling exponent 11.5, a number that is significantly larger than the density-scaling exponents of various Lennard-Jones models that are always below 6.
KW - Liquid Crystal
KW - Molecular Dynamics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547611
DO - https://doi.org/10.1016/j.nocx.2022.100085
VL - 14
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-54761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fürst, Richard
A1 - Hejtmanek, P.
A1 - Vlach, T.
A1 - Repka, J.
A1 - Mozer, V.
A1 - Hajek, P.
T1 - Experimental Evaluation of Carbon Reinforced TRC with Cement Suspension Matrix at Elevated Temperature
N2 - Textile-reinforced concrete (TRC) is a new composite material comprising high-performance concrete and textile reinforcement from textile yarns with a matrix, usually consisting of epoxy resins (ER). The most significant advantage of ER is the homogenization of all filaments in the yarn and full utilization of its tensile potential. Nevertheless, ER matrix is a critical part of TRC design from the perspective of the fire resistance due to its relatively low resistance at temperatures of approximately 120 C. This work expands the previously performed mechanical tests at normal temperatures with cement suspension (CS) as a non-combustible material for the yarn matrix. Here, the mechanical properties of CS matrix at elevated temperatures were verified. It was found that the addition of polypropylene fibers into HPC negatively affected the mechanical results of CS matrix specimens. Simultaneously, thermal insulation effect of the covering layers with different thicknesses did not significantly influence the residual bending strength of specimens with CS matrix and achieved similar results as reference specimens. Furthermore, all specimens with ER matrix progressively collapsed. Finally, CS as a textile reinforcement of yarn matrix appears to be a suitable solution for increasing the temperature resistance of TRC structures and for substituting synthetic resins.
KW - Cement matrix
KW - Cement suspension
KW - Carbon fibers
KW - Textile reinforced concrete
KW - High-performance concrete
KW - Elevated temperature
KW - Fire safety
KW - Fire resistance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550766
DO - https://doi.org/10.3390/polym14112174
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kittner, Maria
A1 - Kerndorff, A.
A1 - Ricking, M.
A1 - Bednarz, M.
A1 - Obermaier, N.
A1 - Lukas, M.
A1 - Asenova, M.
A1 - Bordós, G.
A1 - Eisentraut, Paul
A1 - Hohenblum, P.
A1 - Hudcova, H.
A1 - Humer, F.
A1 - István, T. G.
A1 - Kirchner, M.
A1 - Marushevska, O.
A1 - Nemejcová, D.
A1 - Oswald, P.
A1 - Paunovic, M.
A1 - Sengl, M.
A1 - Slobodnik, J.
A1 - Spanowsky, K.
A1 - Tudorache, M.
A1 - Wagensonner, H.
A1 - Liska, I.
A1 - Braun, U.
A1 - Bannick, C. G.
T1 - Microplastics in the Danube River Basin: A First Comprehensive Screening with a Harmonized Analytical Approach
N2 - In this study, carried out within the Joint Danube Survey 4, a comprehensive microplastic screening in the water column within a large European river basin from its source to estuary, including major tributaries, was realized. The objective was to develop principles of a systematic and practicable microplastic monitoring strategy using sedimentation boxes for collection of suspended particulate matter followed by its subsequent analysis using thermal extraction desorption-gas chromatography/mass spectrometry. In total, 18 sampling sites in the Danube River Basin were investigated. The obtained suspended particulate matter samples were subdivided into the fractions of >100 μm and <100 μm and subsequently analyzed for microplastic mass contents. The results showed that microplastics were detected in all samples, with polyethylene being the predominant polymer with maximum contents of 22.24 μg/mg, 3.23 μg/mg for polystyrene, 1.03 μg/mg for styrene-butadiene-rubber, and 0.45 μg/mg for polypropylene. Further, polymers such as different sorts of polyester, polyacrylates, polylactide, and natural rubber were not detected or below the detection limit. Additional investigations on possible interference of polyethylene signals by algae-derived fatty acids were assessed. In the context of targeted monitoring, repeated measurements provide more certainty in the interpretation of the results for the individual sites. Nevertheless, it can be stated that the chosen approach using an integrative sampling and determination of total plastic content proved to be successful.
KW - Thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS), monitoring
KW - Microplastics
KW - River
KW - Suspended particulate matter (SPM)
KW - Sedimentation box (SB)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551444
DO - https://doi.org/10.1021/acsestwater.1c00439
VL - 2
IS - 7
SP - 1174
EP - 1181
PB - ACS Publications
AN - OPUS4-55144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogler, Nico
A1 - Lehmann, Jens
A1 - Bohlmann, Tatjana
A1 - Kronemann, Jens
T1 - Gel-bound Colourants as a Substitute for the Sprayed Application of pH-Indicator Solution
N2 - In general, pH-sensitive colorants such as phenolphthalein are applied on freshly split surfaces of building structures to determine the state of carbonation. For years, it has been known that the aerosols of phenolphthalein are suspected of being carcinogenic. Hence, more work has currently being done on alternative indicators for the use in research and the use on construction sites. Over the past years, mainly pH indicators from other research areas and natural dyes were investigated for their usability to cementitious systems. This paper presents the experimental results of using phenolphthalein solution bound in agar-agar gel. This gel-bound indicator allows the future use of the already known phenolphthalein dye without the health hazards for the user. To demonstrate the flexibility of the gel-bound colorant, different application forms of the indicator were carried out and assessed. In addition, the results obtained by the different methods were statistically evaluated to ensure validity.
The accuracy of the results was confirmed by thermogravimetric analysis and IR spectroscopic studies as reference methods. It has also succeeded to demonstrate the comparability of the results achieved by the gel-bound colorant with the results of the common sprayed application method. As an additional gain in knowledge, comparative results of indicator tests, TGA analysis, and FTIR investigation are shown.
KW - Concrete Carbonation
KW - Gel-bound Colorants
KW - pH Indicator
KW - Thermal Gravimetric Analysis
KW - FTIR-ATR Measurements
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551493
UR - http://www.sciencepublishinggroup.com/j/ajce
DO - https://doi.org/10.11648/j.ajce.20221003.16
SN - 2330-8729
SN - 2330-8737
VL - 10
IS - 3
SP - 135
EP - 144
PB - Science Publishing Group
CY - New York, NY
AN - OPUS4-55149
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Coplen, T. B.
A1 - Holden, N. E.
A1 - Ding, T.
A1 - Meijer, H. A. J.
A1 - Vogl, Jochen
A1 - Zhu, X.
T1 - The Table of Standard Atomic Weights—An exercise in consensus
N2 - The present Table of Standard Atomic Weights (TSAW) of the elements is perhaps one of the most familiar data sets in science. Unlike most parameters in physical science whose values and uncertainties are evaluated using the “Guide to the Expression of Uncertainty in Measurement” (GUM), the majority of standard atomic weight values and their uncertainties are consensus values, not GUM-evaluated values. The Commission on Isotopic Abundances and Atomic Weights of the International Union of Pure and Applied Chemistry (IUPAC) regularly evaluates the literature for new isotopic-abundance measurements that can lead to revised standard atomic-weight values, Ar(E) for element E.
The Commission strives to provide utmost clarity in products it disseminates, namely the TSAW and the Table of Isotopic Compositions of the Elements (TICE). In 2016, the Commission recognized that a guideline recommending the expression of uncertainty listed in parentheses following the standard atomic-weight value, for example, Ar(Se) = 78.971(8), did not agree with the GUM, which suggests that this parenthetic notation be reserved to express standard uncertainty, not the expanded uncertainty used in the TSAW and TICE. In 2017, to eliminate this noncompliance with the GUM, a new format was adopted in which the uncertainty value is specified by the “±” symbol, for example, Ar(Se) = 78.971 ± 0.008. To clarify the definition of uncertainty, a new footnote has been added to the TSAW. This footnote emphasizes that an atomic-weight uncertainty is a consensus (decisional) uncertainty. Not only has the Commission shielded users of the TSAW and TICE from unreliable measurements that appear in the literature as a result of unduly small uncertainties, but the aim of IUPAC has been fulfilled by which any scientist, taking any natural sample from commerce or research, can expect the sample atomic weight to lie within Ar(E) ± its uncertainty almost all of the time.
KW - Atomic weight
KW - Standard atomic weight
KW - Uncertainty
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551299
DO - https://doi.org/10.1002/rcm.8864
SN - 1097-0231
VL - 36
IS - 15
SP - 1
EP - 15
PB - Wiley
AN - OPUS4-55129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Roed, L.
A1 - Mehri, S.
A1 - Ingebrigtsen, T.
A1 - Hecksher, T.
A1 - Dyre, J.
A1 - Niss, K.
T1 - Predicting nonlinear physical aging of glasses from equilibrium relaxation via the material time
N2 - The noncrystalline glassy state of matter plays a role in virtually all fields of materials science and offers complementary properties to those of the crystalline counterpart. The caveat of the glassy state is that it is out of equilibrium and therefore exhibits physical aging, i.e., material properties change over time. For half a century, the physical aging of glasses has been known to be described well by the material-time concept, although the existence of a material time has never been directly validated. We do this here by successfully predicting the aging of the molecular glass 4-vinyl-1,3-dioxolan-2-one from its linear relaxation behavior. This establishes the defining property of the material time. Via the fluctuation-dissipation theorem, our results imply that physical aging can be predicted from thermal-equilibrium fluctuation data, which is confirmed by computer simulations of a binary liquid mixture.
KW - Physical aging
KW - Equilibrium relaxation
KW - Glass
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546015
DO - https://doi.org/10.1126/sciadv.abl9809
SN - 2375-2548
VL - 8
IS - 11
SP - 1
EP - 8
PB - American Association for the Advancement of Science
CY - Washington, DC
AN - OPUS4-54601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hieu, D.T.
A1 - Kosslick, H.
A1 - Riaz, M.
A1 - Schulz, A.
A1 - Springer, A.
A1 - Frank, M.
A1 - Jäger, Christian
A1 - Minh Thu, N.T.
A1 - Son, L.T.
T1 - Acidity and Stability of Bronsted Acid Sites in Green Clinoptilolite Catalysts and Catalytic Performance in the Etherification of Glycerol
N2 - Natural zeolite clinoptilolite CLIN with a framework ratio of Si/Al ≥ 4 containing mainly potassium and calcium ions in its internal channel system was used as a starting material. The acidic HCLIN catalysts were prepared under soft conditions avoiding the use of environmental less benign mineral acids. The starting material was ion exchanged using a 0.2 M aqueous ammonium nitrate solution at a temperature 80 ◦C for 2 h. The obtained NH4CLIN was converted into the acid HCLIN catalyst by calcination at 300–600 ◦C. The obtained samples were characterized by XRD, FTIR, SEM/TEM, AAS, and EDX element mapping. The state of aluminium and silicon was studied by 27Al- and 29SiMAS NMR spectroscopy. The textural properties of the catalysts were investigated by nitrogen adsorption and desorption measurements. The Brønsted acidity of the HCLIN catalysts was studied by temperature-programmed decomposition of the exchanged ammonium ions releasing ammonia as well as 1H MAS NMR, {1H–27Al} Trapdor, and {1H–27Al}
Redor experiments. The strongly agglomerated samples were crystalline and thermally stable up to >500 ◦C. Although a part of the clinoptilolite framework is maintained up to 600 ◦C, a loss of crystallinity is already observed starting from 450 ◦C. The specific surface areas of the starting CLIN and ammonium exchanged NH4CLIN are low with ca. 26 m2/g. The pores are nearly blocked by the exchangeable cations located in the zeolite pores. The thermal decomposition of the ammonium ions by calcination at 400 ◦C causes an opening of the pore entrances and a markable increase in the specific micropore area and micropore volume to ca. 163 m2/g and 0.07 cm3/g, respectively. It decreases with further rising calcination temperature indicating some structural loss. The catalysts show a broad distribution of Brønsted acid sites (BS) ranging from weak to strong sites as indicated the
thermal decomposition of exchanged ammonium ions (TPDA). The ammonium ion decomposition leaving BS, i.e., H+ located at Al–O–Si framework bridges, starts at ≥250 ◦C. A part of the Brønsted sites is lost after calcination specifically at 500 ◦C. It is related to the formation of penta-coordinated aluminium at the expense of tetrahedral framework aluminium. The Brønsted sites are partially recreated after repeated ammonium ion exchange. The catalytic performance of the acidic HCLIN
catalysts was tested in the etherification of glycerol as a green renewable resource with different C1 -C4 alcohols. The catalysts are highly active in the etherification of glycerol, especially with alcohols containing the branched, tertiary alkyl groups. Highest activity is observed with the soft activated catalyst HCLIN300 (300 ◦C, temperature holding time: 1 min). A total of 78% conversion of glycerol to mono and di ether were achieved with tert-butanol at 140 ◦C after 4 h of reaction.
The mono- and di-ether selectivity were 75% and 25%, respectively. The catalyst can be reused.
KW - Etherification
KW - Glycerol
KW - Zeolite
KW - Clinoptilolite
KW - Bronsted acidity
KW - Dehydroxylation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546982
DO - https://doi.org/10.3390/catal12030253
VL - 12
IS - 3
SP - 1
EP - 24
PB - MDPI
AN - OPUS4-54698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hirschberg, L.
A1 - Bake, Friedrich
A1 - Knobloch, K.
A1 - Hulshoff, S.
A1 - Hirschberg, A.
T1 - Experimental investigations of indirect noise due to modulation of axial vorticity and entropy upstream of a choked nozzle
N2 - An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in the main flow. This eventually induces a large downstream acoustic pulse when tangential injection is interrupted. The magnitude of the resulting sound pulse can reach that of a quasi-steady response of the nozzle to a large air patch with a uniform stagnation temperature equal to that of the upstream-injected heated air. This hypothesis is consistent with the fact that the initial indirect-sound pulse is identical to one obtained with unheated air injection. The authors posit that – given all of the insight gleaned from them in this case – acoustic measurements of indirect sound appear to be a potentially useful diagnostic tool.
KW - Aeroacoustics
KW - Indirect combustion noise
KW - Vorticity noise
KW - Entropy noise
KW - Swirl
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548331
DO - https://doi.org/10.1016/j.jsv.2022.116989
SN - 0022-460X
VL - 532
SP - 1
EP - 22
PB - Elsevier Ltd.
AN - OPUS4-54833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lecompagnon, Julien
A1 - Ahmadi, Samim
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
T1 - Thermographic detection of internal defects using 2D photothermal super resolution reconstruction with sequential laser heating
N2 - Thermographic photothermal super resolution reconstruction enables the resolution of internal defects/inhomogeneities below the classical limit, which is governed by the diffusion properties of thermal wave propagation. Based on a combination of the application of special sampling strategies and a subsequent numerical optimization step in post-processing, thermographic super resolution has already proven to be superior to standard thermographic methods in the detection of one-dimensional defect/inhomogeneity structures. In our work, we report an extension of the capabilities of the method for efficient detection and resolution of defect cross sections with fully two-dimensional structured laser-based heating. The reconstruction is carried out using one of two different algorithms that are proposed within this work. Both algorithms utilize the combination of several coherent measurements using convex optimization and exploit the sparse nature of defects/inhomogeneities as is typical for most nondestructive testing scenarios. Finally, the performance of each algorithm is rated on reconstruction quality and algorithmic complexity. The presented experimental approach is based on repeated spatially structured heating by a high power laser. As a result, a two-dimensional sparse defect/inhomogeneity map can be obtained. In addition, the obtained results are compared with those of conventional thermographic inspection methods that make use of homogeneous illumination. Due to the sparse nature of the reconstructed defect/inhomogeneity map, this comparison is performed qualitatively.
KW - Thermography
KW - Super resolution
KW - NDT
KW - Inspection
KW - Internal defects
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548351
DO - https://doi.org/10.1063/5.0088102
SN - 1089-7550
VL - 131
IS - 18
SP - 1
EP - 12
PB - AIP Publishing
AN - OPUS4-54835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Van Driessche, A. E. S.
T1 - Editorial for special issue "Formation of sulfate minerals in natural and industrial environments"
N2 - Sulfate is abundant in the environment and, as a result, sulfate-containing minerals constitute a large and important focus of research. These minerals play an important role in many geochemical and industrial processes, including the sulfur cycle, the construction industry (e.g., plaster of Paris), fault tectonics, acid mine drainage, and even rare biominerals. Important to note are the abundant amounts of sulfate (minerals) located on the surface of Mars, and in meteorites, extending the relevance of this mineral group beyond the realm of our planet. In geological systems, sulfate minerals such as barite are also important for indicating certain sedimentation environments. In this regard, sulfate deposits can be used to evaluate the redox state of ancient oceans during early Earth time periods.
KW - Calcium sulfate
KW - Sulfates
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546794
DO - https://doi.org/10.3390/min12030299
SN - 2075-163X
VL - 12(3)
IS - Special issue "Formation of sulfate minerals in natural and industrial environments"
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-54679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chambers, M. S.
A1 - Hunter, R. D.
A1 - Hollamby, M. J.
A1 - Pauw, Brian Richard
A1 - Smith, A. J.
A1 - Snow, T.
A1 - Danks, A. E.
A1 - Schnepp, Z.
T1 - In Situ and Ex Situ X‑ray Diffraction and Small-Angle X‑ray Scattering Investigations of the Sol−Gel Synthesis of Fe3N and Fe3C
N2 - Iron nitride (Fe3N) and iron carbide (Fe3C) nanoparticles can be prepared via sol−gel synthesis. While sol−gel methods are simple, it can be difficult to control the crystalline composition, i.e., to achieve a Rietveld-pure product. In a previous in situ synchrotron study of the sol−gel synthesis of Fe3N/Fe3C, we showed that the reaction proceeds as follows:
Fe3O4 → FeOx → Fe3N → Fe3C. There was considerable overlap between the different phases, but we were unable to ascertain whether this was due to the experimental setup (side-on heating of a quartz capillary which could lead to thermal gradients) or whether individual particle reactions proceed at different rates. In this paper, we use in situ wide- and small-angle X-ray scattering (wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS)) to demonstrate that the overlapping phases are indeed due to variable reaction rates. While the initial oxide nanoparticles have a small range of diameters, the size range expands considerably and very rapidly during the oxide−nitride transition. This has implications for the isolation of Rietveld-pure Fe3N, and in an extensive laboratory study, we were indeed unable to isolate phasepure Fe3N. However, we made the surprising discovery that Rietveld-pure Fe3C nanoparticles can be produced at 500 °C with a sufficient furnace dwell time. This is considerably lower than the previous reports of the sol−gel synthesis of Fe3C nanoparticles.
KW - Small-angle X-ray Scattering
KW - SAXS
KW - Diffraction
KW - XRD
KW - Scattering
KW - Sol-gel
KW - Iron nitride
KW - Nanoparticles
KW - Iron carbide
KW - Catalyst
KW - In-situ
KW - Ex-situ
KW - Synthesis
KW - Synchrotron
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548226
DO - https://doi.org/10.1021/acs.inorgchem.1c03442
VL - 61
IS - 18
SP - 6742
EP - 6749
PB - ACS Publications
CY - Washington
AN - OPUS4-54822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - Hertwig, Andreas
T1 - Application of imaging ellipsometry and white light interference microscopy for detection of defects in epitaxially grown 4H-SiC layers
N2 - Critical defects, also known as device killers, in wide bandgap semiconductors significantly affect the performance of power electronic devices. We used the methods imaging ellipsometry (IE) and white light interference microscopy (WLIM) in a hybrid optical metrology study for fast and non-destructive detection, classification, and characterisation of defects in 4H–SiC homoepitaxial layers on 4H–SiC substrates. Ellipsometry measurement results are confirmed by WLIM. They can be successfully applied for wafer characterisation already during production of SiC epilayers and for subsequent industrial quality control.
T2 - EOS Annual Meeting (EOSAM 2022)
CY - Porto
DA - 12.09.2022
KW - Imaging ellipsometry
KW - White light interference microscopy
KW - 4H–SiC
KW - Defects
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574209
DO - https://doi.org/10.1051/jeos/2023018
SN - 1990-2573
VL - 19
IS - 1
SP - 1
EP - 8
PB - EDP Sciences
AN - OPUS4-57420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valdestilhas, Andre
A1 - Bayerlein, Bernd
A1 - Moreno Torres, Benjami
A1 - Zia, Ghezal Ahmad Jan
A1 - Muth, Thilo
T1 - The Intersection Between Semantic Web and Materials Science
N2 - The application and benefits of Semantic Web Technologies (SWT) for managing, sharing, and (re-)using of research data are demonstrated in implementations in the field of Materials Science and Engineering (MSE). However, a compilation and classification are needed to fully recognize the scattered published works with its unique added values. Here, the primary use of SWT at the interface with MSE is identified using specifically created categories. This overview highlights promising opportunities for the application of SWT to MSE, such as enhancing the quality of experimental processes, enriching data with contextual information in knowledge graphs, or using ontologies to perform specific queries on semantically structured data. While interdisciplinary work between the two fields is still in its early stages, a great need is identified to facilitate access for nonexperts and develop and provide user-friendly tools and workflows. The full potential of SWT can best be achieved in the long term by the broad acceptance and active participation of the MSE community. In perspective, these technological solutions will advance the field of MSE by making data FAIR. Data-driven approaches will benefit from these data structures and their connections to catalyze knowledge generation in MSE.
KW - Linked open data
KW - Materials science
KW - Ontology
KW - Semantic web
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575506
DO - https://doi.org/10.1002/aisy.202300051
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-57550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Hufschläger, Daniel
A1 - Gohlke, Dirk
A1 - Weise, Matthias
A1 - Ilse, D.
A1 - Hillger, W.
A1 - Szewieczek, A.
T1 - Phased-Array-Prüfköpfe für luftgekoppelte Ultraschallprüfung auf Basis von zellulären Kunststoffen
N2 - Luftgekoppelte Ultraschallprüfung setzt sich immer häufiger gegen die konventionelle Ultraschallprüfung von Leichtbaukomponenten durch, und zwar in vielen Industriezweigen von der Holzindustrie bis zur Luftfahrt. Während die Phased-Array-Technik mittlerweile zu dem industriellen Standard im Bereich der Prüfung mit Ankopplung gehört, wird luftgekoppelte Ultraschallprüfung meist mit zwei Wandlern in Durchschallung durchgeführt. Deswegen werden Vorteile der Phased-Array-Technik wie beispielsweise elektronische Fokussierung oder Schwenkung des Einschallwinkels für luftgekoppelte Prüfung selten genutzt.
In diesem Beitrag werden die laufenden Arbeiten an der Entwicklung eines neuen Phased-Array-Geräts vorgestellt, mit dem Schwerpunkt an der Charakterisierung der Prüfköpfe und ihrer Schallfelder. Das Gerät besteht aus einem linearen Phased-Array-Prüfkopf, einer Sende- und einer Empfangseinheit. Die Hauptinnovation unserer Arbeit ist die Anwendung von zellulären Kunststoffen für den Bau eines Arrays, wobei der Sender mit Hochspannung von ca. 1500 V angeregt wird. Geladene zelluläre Polymere werden auch Ferroelektrete oder Piezoelektrete genannt. Sie weisen ein sehr niedriges Elastizitätsmodul und dadurch eine niedrige akustische Impedanz auf, so dass auf den Einbau von Anpassschichten verzichtet werden kann.
Eine sehr niedrige mechanische Kreuzkopplung bei Ferroelektreten ermöglicht eine unabhängige Anregung einzelner Elemente, was bei Piezokompositen deutlich schwieriger wäre. Die Entwicklung der Array-Prüfköpfe wurde durch Berechnungen des Schallfeldes unterstützt, die auf Punktquellensynthese basieren. Die beabsichtigte Anwendung von Phased-Array-Prüfköpfen und des Prüfsystems sind die Durchschallung mit Fokussierung, elektronischer Scan und die Schwenkung des Einschallwinkels zur Anregung von geführten Wellen, angewandt an carbonfaserverstärkten Kunststoffen und ähnlichen Materialien. Die Anwendung von geführten Wellen bietet die Perspektive, Bauteile mit einseitiger Zugänglichkeit zu prüfen.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Luftgekoppelte Ultraschallprüfung
KW - Ferroelektret
KW - Ultraschallwandler
KW - Phased Array
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575564
SP - 1
EP - 6
AN - OPUS4-57556
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hufschläger, Daniel
A1 - Gohlke, Dirk
A1 - Weise, Matthias
A1 - Bente, K.
A1 - Gaal, Mate
T1 - Thermoakustische Gruppenstrahler: Theorie und Anwendungen
N2 - Bei der Prüfung von Werkstücken mit empfindlichen Oberflächen oder auch hydrophilen Werkstoffen sind traditionelle ultraschallbasierte zerstörungsfreie Prüfmethoden wie die Kontakttechnik oder die Tauchtechnik in vielen Anwendungsfällen aufgrund der Flüssigkeitsankopplung nicht anwendbar.
Die luft-gekoppelte Ultraschallprüfung umgeht diese Problematik und eröffnet neue Prüfszenarien. Derzeit werden zwei Varianten der Schallerzeugung als vielversprechend angesehen: ferroelektrische Folien und thermoakustische Dünnschichtwandler. Thermoakustische Wandler ermöglichen die resonanzfreie Erzeugung von Ultraschall und somit kurze zeitliche Impulse sowie eine sehr breitbandige Anregung. Durch die Verwendung von gekrümmten Substraten ist sowohl eine Herstellung von planaren als auch fokussierten Wandlern möglich.
Dieser Beitrag präsentiert die letzten Forschungsergebnisse im Bezug auf thermoakustischen Wandlern, welche derzeit in einen thermoakustischen Gruppenstrahler münden. Gruppenstrahler erlauben die simultane Änderung des Einschallwinkels, sowie die Verschiebung des Fokuspunktes während der Verwendung.
Durch die Verbindung beider Schlüsseltechnologien, der thermoakustischen Anregung und des Gruppenstrahlerprinzips, wird das Spektrum der klassischen ZfP-Anwendungen, sowie moderner Ansätze wie der Anregung von geführten Wellen oder der Strukturüberwachung erheblich erweitert und bereichert.
Dabei soll innerhalb dieses Beitrages auf die Modellierung des Schallfeldes, die elementweise Charakterisierung und verschiedene Anwendungsszenarien eingegangen werden.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Luftgekoppelte Ultraschallprüfung
KW - Thermoakustik
KW - Ultraschallwandler
KW - Phased Array
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575599
SP - 1
EP - 6
AN - OPUS4-57559
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmitt, M.
A1 - Casperson, Ralf
A1 - Baensch, F.
T1 - Ein Überblick über die Normung in der zerstörungsfreien Prüfung
N2 - Normung und Standardisierung in der zerstörungsfreien Prüfung finden auf nationaler, europäischer und internationaler Ebene statt. Durch die Übernahme von Leitungsfunktionen in diesen Gremien kann ein deutlicher steuernder Einfluss auf Themen und Inhalte der Normen genommen werden. Unabdingbar für den Erfolg ist zusätzlich das persönliche Engagement der Fachexpert*innen in den nationalen Gremien und den europäischen und internationalen Arbeitsgruppen. Denn wer nicht normt wird genormt und muss letztlich Regeln verwenden, die andere entsprechend ihrer eigenen Interessen gestalten. Voraussetzung für die Teilnahme in europäischen und internationalen Normungsgremien ist die Mitwirkung in den entsprechenden nationalen Spiegelgremien der nationalen Normungsinstitute, welche die europäischen und internationalen Aktivitäten spiegeln und die Fachexperten für die Mitarbeit autorisieren.
Gezeigt werden die relevante Gremienstruktur auf internationaler Ebene (ISO/TC 135 “Non-destructive testing”, ISO/TC 44/SC 5 “Testing and inspection of welds”), auf europäischer Ebene (CEN/TC 138 “Zerstörungsfreie Prüfverfahren”), die Struktur der nationalen deutschen Spiegelgremien, das Zusammenspiel der Gremien, und die Einflussmöglichkeiten.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Normung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575759
UR - https://jahrestagung.dgzfp.de/Portals/jt2023/bb/P4.pdf
VL - 2023
SP - 1
EP - 6
PB - DGZfP
CY - Berlin
AN - OPUS4-57575
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wu, J.
A1 - Gong, M.
A1 - Zhang, W.
A1 - Mehmood, Asad
A1 - Zhang, J.
A1 - Ali, G.
A1 - Kucernak, A.
T1 - Simultaneously incorporating atomically dispersed Co-Nₓ sites with graphitic carbon layer-wrapped Co₉S₈ nanoparticles for oxygen reduction in acidic electrolyte
N2 - A facile yet robust synthesis is reported herein to simultaneously incorporate atomically dispersed Co-Nₓ sites with graphitic layer-protected Co₉S₈ nanoparticles (denoted as Co SACs+Co₉S₈) as an efficient electrocatalyst for oxygen reduction in acidic solution. The Co SACs+Co₉S₈ catalyst shows low H₂O₂ selectivity (∼5 %) with high half-wave potential (E1/2) of ∼0.78 V(RHE) in 0.5 M H₂SO₄. The atomic sites of the catalyst were quantified by a nitrite stripping method and the corresponding site density of the catalyst is calculated to be 3.2×10¹⁸ sites g⁻¹. Besides, we also found the presence of a reasonable amount of Co₉S₈ nanoparticles is beneficial for the oxygen electrocatalysis. Finally, the catalyst was assembled into a membrane electrode assembly (MEA) for evaluating its performance under more practical conditions in proton exchange membrane fuel cell (PEMFC) system.
KW - Co−N-Cs
KW - Fuel cells
KW - Single-atom catalysts
KW - Oxygen reduction reaction
KW - PGM-free catalysts
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575993
DO - https://doi.org/10.1002/celc.202300110
SN - 2196-0216
VL - 10
IS - 12
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raysyan, Anna
A1 - Zwigart, S.
A1 - Eremin, S. A.
A1 - Schneider, Rudolf
T1 - BPA Endocrine Disruptor Detection at the Cutting Edge: FPIA and ELISA Immunoassays
N2 - BPA is a chemical commonly used in the production of polymer-based materials that can have detrimental effects on the thyroid gland and impact human reproductive health. Various expensive methods, such as liquid and gas chromatography, have been suggested for detecting BPA.
The fluorescence polarization immunoassay (FPIA) is an inexpensive and efficient homogeneous mix-and-read method that allows for high-throughput screening. FPIA offers high specificity and sensitivity and can be carried out in a single phase within a timeframe of 20–30 min. In this study, new tracer molecules were designed that linked the fluorescein fluorophore with and without a spacer to the bisphenol A moiety. To assess the influence of the C6 spacer on the sensitivity of an assay based on the respective antibody, hapten–protein conjugates were synthesized and assessed for performance in an ELISA setup, and this resulted in a highly sensitive assay with a detection limit of 0.05 µg/L. The lowest limit of detection was reached by employing the spacer derivate in the FPIA and was 1.0 µg/L, working range from 2 to 155 µg/L. The validation of the methods was conducted using actual samples compared to LC–MS/MS, which served as the reference method. The FPIA and ELISA both demonstrated satisfactory concordance.
KW - Fluorescence Polarization
KW - Enzyme-Linked Immunosorbent Assay
KW - Endokriner Disruptor
KW - Bisphenol A
KW - Freisetzung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579497
DO - https://doi.org/10.3390/bios13060664
VL - 13
IS - 6
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-57949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tschirschwitz, Rico
A1 - Bernardy, Christopher
A1 - Wagner, Patrick
A1 - Rappsilber, Tim
A1 - Liebner, Christian
A1 - Hahn, S.-K.
A1 - Krause, U.
T1 - Harmful effects of lithium-ion battery thermal runaway: scale-up tests from cell to second-life modules
N2 - For a comprehensive safety assessment of stationary lithium-ion-battery applications, it is necessary to better understand the consequences of thermal runaway (TR). In this study, experimental tests comprising twelve TR experiments including four single-cell tests, two cell stack tests and six second-life module tests (2.65 kW h and 6.85 kW h) with an NMC-cathode under similar initial conditions were conducted. The temperature (direct at cells/modules and in near field), mass loss, cell/module voltage, and qualitative vent gas composition (Fourier transform infrared (FTIR) and diode laser spectroscopy (DLS) for HF) were measured. The results of the tests showed that the battery TR is accompanied by severe and in some cases violent chemical reactions. In most cases, TR was not accompanied by pregassing of the modules. Jet flames up to a length of 5 m and fragment throwing to distances to more than 30 m were detected. The TR of the tested modules was accompanied by significant mass loss of up to 82%. The maximum HF concentration measured was 76 ppm, whereby the measured HF concentrations in the module tests were not necessarily higher than that in the cell stack tests.
Subsequently, an explosion of the released vent gas occurred in one of the tests, resulting in the intensification of the negative consequences. According to the evaluation of the gas measurements with regard to toxicity base on the “Acute Exposure Guideline Levels” (AEGL), there is some concern with regards to CO, which may be equally as important to consider as the release of HF.
KW - Large-scale tests
KW - Lithium-ion battery
KW - Gas emission
KW - Thermal runaway
KW - Consequences
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579054
DO - https://doi.org/10.1039/D3RA02881J
SN - 2046-2069
VL - 13
IS - 30
SP - 20761
EP - 20779
PB - Royal Society of Chemistry (RSC)
CY - Cambridge, UK
AN - OPUS4-57905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jiang, Shixiong
A1 - Marco, H. G.
A1 - Scheich, Nina
A1 - He, S.
A1 - Wang, Z.
A1 - Gäde, G.
A1 - McMahon, Dino Peter
T1 - Comparative analysis of adipokinetic hormones and their receptors in Blattodea reveals novel patterns of gene evolution
N2 - Adipokinetic hormone (AKH) is a neuropeptide produced in the insect corpora cardiaca that plays an essential role in mobilising carbohydrates and lipids from the fat body to the haemolymph. AKH acts by binding to a rhodopsin-like G protein-coupled receptor (GPCR), the adipokinetic hormone receptor (AKHR). In this study, we tackle AKH ligand and receptor gene evolution as well as the evolutionary origins of AKH gene paralogues from the order Blattodea (termites and cockroaches). Phylogenetic analyses of AKH precursor sequences point to an ancient AKH gene duplication event in the common ancestor of Blaberoidea, yielding a new group of putative decapeptides. In total, 16 different AKH peptides from 90 species were obtained. Two octapeptides and seven putatively novel decapeptides are predicted for the first time. AKH receptor sequences from 18 species, spanning solitary cockroaches and subsocial wood roaches as well as lower and higher termites, were subsequently acquired using classical molecular methods and in silico approaches employing transcriptomic data. Aligned AKHR open reading frames revealed 7 highly conserved transmembrane regions, a typical arrangement for GPCRs.
Phylogenetic analyses based on AKHR sequences support accepted relationships among termite, subsocial (Cryptocercus spp.) and solitary cockroach lineages to a large extent, while putative post-translational modification sites do not greatly differ between solitary and subsocial roaches and social termites. Our study provides important information not only for AKH and AKHR functional research but also for further analyses interested in their development as potential candidates for biorational pest control agents against invasive termites and cockroaches.
KW - Adipokinetic hormone
KW - Adipokinetic hormone receptor
KW - ‘Green’ pesticide
KW - Neuropeptide
KW - Termite
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579141
DO - https://doi.org/10.1111/imb.12861
SN - 0962-1075
SP - 1
EP - 19
PB - Wiley online library
CY - London, UK
AN - OPUS4-57914
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stratulat, C.
A1 - Ginghina, R. E.
A1 - Bratu, A. E.
A1 - Isleyen, A.
A1 - Tunc, M.
A1 - Hafner-Vuk, K.
A1 - Frey, A. M.
A1 - Kjeldsen, H.
A1 - Vogl, Jochen
T1 - Development- and Validation-Improved Metrological Methods for the Determination of Inorganic Impurities and Ash Content from Biofuels
N2 - In this study, five laboratories, namely, BRML (Romania), TUBITAK UME (Turkey), IMBIH (Bosnia and Herzegovina), BAM (Germany), and DTI (Denmark), developed and validated analytical procedures by ICP-MS, ICP-OES, MWP-AES, WD-XRF, and ID-MS for the determination of inorganic
impurities in solid and liquid biofuels, established the budget of uncertainties, and developed the method for determining the amount of ash in the measurement range 0–1.2% with absolute repeatability less than 0.1% and absolute reproducibility of 0.2% (according to EN ISO 18122). In order to create homogeneous certified reference materials, improved methodologies for the measurement and characterization of solid and liquid biofuels were developed. Thus, information regarding the precision, accuracy, and bias of the method, and identifying the factors that intervened in the measurement of uncertainty were experimentally determined, supplementing the information from the existing standards in the field.
KW - Development
KW - Validate method
KW - Biodiesel
KW - ICP-MS
KW - ICP-OES
KW - MW-AES
KW - WD-XRF
KW - ID-MS
KW - Inorganic impurities
KW - Ash content
KW - Wood chips
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578743
DO - https://doi.org/10.3390/en16135221
VL - 16
IS - 13
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-57874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kröll, Mirco
T1 - Benefits of novel tools open to Industry from Open Innovation Testbeds. Effects of harmonised procedures in (digital) Tribology
N2 - The work on Tribology, digitalisation, and the harmonised procedures developed in i-TRIBOMAT Open Innovation Testbed was presented. The project develops procedures and shares ideas on how to deal with characterisation techniques and provide services to end users in different places and locations, which is realised by adopting a common and widely agreed procedures. i-TRIBOMAT is active also via YouTube platform to enhance communication and spread the word amongst the interested parties and society.
T2 - Workshop of NanoMECommons project: "Materials characterisation challenges to support the industry transition in the digital era"
CY - Online meeting
DA - 13.12.2021
KW - Tribology
KW - i-TRIBOMAT
KW - Characterisation
KW - Digitalisation
KW - Interoperability
KW - Harmonisation
KW - Green Deal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548909
DO - https://doi.org/10.5281/zenodo.6339985
SP - 14
EP - 17
AN - OPUS4-54890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
T1 - Hochaufgelöste thermografische Detektion eingeschlossener Defekte mit Hilfe von 2Dstrukturierten Beleuchtungsmustern
N2 - Für die aktive Thermografie als zerstörungsfreie Prüfmethode galt lange Zeit die Faustformel, dass die Auflösung interner Defekte/Inhomogenitäten auf ein Verhältnis von Defekttiefe/Defektgröße ≤ 1 beschränkt ist. Die Ursache hierfür liegt in der diffusiven Natur der Wärmeleitung in Festkörpern. Sogenannte Super-Resolution-Ansätze erlauben seit Kurzem die Überwindung dieser physikalischen Grenze um ein Vielfaches. Damit ergibt sich die attraktive Möglichkeit die Thermografie von einem rein oberflächensensitiven Prüfverfahren hin zu einem Verfahren mit verbesserter Tiefenreichweite zu entwickeln. Wie weit diese Entwicklung getrieben werden kann, ist Gegenstand aktueller Forschung.
Wir konnten bereits zeigen, dass diese klassische Grenze für 1D- und 2D Defektgeometrien mit Hilfe des Abscannens des Prüfkörpers mittels einzelner Laserspots und der anschließenden Anwendung von photothermischer Super-Resolution-Rekonstruktion überwunden werden kann. Bei dieser Methode wird eine Kombination aus sequenzieller räumlich strukturierter Beleuchtung und numerischen Optimierungsmethoden eingesetzt. Dies geschieht allerdings auf Kosten der experimentellen Komplexität, die zu einer langen Messdauer, großen Datensätzen und langwieriger numerischer Auswertung führt.
In dieser Arbeit berichten wir über einen neuen experimentellen Ansatz, bei dem räumlich strukturierte 2D-Beleuchtungsmuster in Verbindung mit Compressed-Sensing und Computational-Imaging-Methoden verwendet werden, um die experimentelle Komplexität deutlich zu verringern und die Methode für die Untersuchung größerer Prüfflächen nutzbar zu machen.
Der experimentelle Ansatz basiert dabei auf der wiederholten (blinden) photothermischen Anregung mit räumlich strukturierten 2D-Mustern unter Verwendung moderner Projektortechnik und eines Hochleistungslasers. In der anschließenden numerischen Rekonstruktion werden mehrere Messungen unter Ausnutzung der Joint-Sparsity der Defekte innerhalb des Prüfkörpers mittels nichtlinearer konvexer Optimierungsmethoden kombiniert. Als Ergebnis kann eine 2D-sparse Defekt-/Inhomogenitätskarte erstellt werden.
T2 - DGZfP-Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Thermografie
KW - Super resolution
KW - NDT
KW - ZfP
KW - Eingeschlossene Defekte
KW - Projektor
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548945
SN - 978-3-947971-25-1
VL - 177
SP - 1
EP - 16
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung
AN - OPUS4-54894
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Olscher, C.
A1 - Jandric, A.
A1 - Zafiu, C.
A1 - Part, Florian
T1 - Evaluation of marker materials and spectroscopic methods for tracer-based sorting of plastic wastes
N2 - Plastics are a ubiquitous material with good mechanical, chemical and thermal properties, and are used in all industrial sectors. Large quantities, widespread use, and insufficient management of plastic wastes lead to low recycling rates. The key challenge in recycling plastic waste is achieving a higher degree of homogeneity between the different polymer material streams. Modern waste sorting plants use automated sensor-based sorting systems capable to sort out commodity plastics, while many engineering plastics, such as polyoxymethylene (POM), will end up in mixed waste streams and are therefore not recycled. A novel approach to increasing recycling rates is tracer-based sorting (TBS), which uses a traceable plastic additive or marker that enables or enhances polymer type identification based on the tracer’s unique fingerprint (e.g., fluorescence). With future TBS applications in mind, we have summarized the literature and assessed TBS techniques and spectroscopic detection methods. Furthermore, a comprehensive list of potential tracer substances suitable for thermoplastics was derived from the literature. We also derived a set of criteria to select the most promising tracer candidates (3 out of 80) based on their material properties, toxicity profiles, and detectability that could be applied to enable the circularity of, for example, POM or other thermoplastics.
KW - Circular economy
KW - Post-consumer plastic waste
KW - Plastic waste recycling
KW - Tracer-based sorting
KW - Sensor-based sorting
KW - Spectroscopy
KW - Fluorescent markers
KW - Thermoplastics
KW - Polyoxymethylene
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555624
DO - https://doi.org/10.3390/polym14153074
SN - 2073-4360
VL - 14
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-55562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hobmeier, K.
A1 - Oppermann, M.
A1 - Stasinski, N.
A1 - Kremling, A.
A1 - Pflüger-Grau, K.
A1 - Kunte, Hans-Jörg
A1 - Marin Sanguino, A.
T1 - Metabolic engineering of Halomonas elongata: Ectoine secretion is increased by demand and supply driven approaches
N2 - The application of naturally-derived biomolecules in everyday products, replacing conventional synthetic manufacturing, is an ever-increasing market. An example of this is the compatible solute ectoine, which is contained in a plethora of treatment formulations for medicinal products and cosmetics. As of today, ectoine is produced in a scale of tons each year by the natural producer Halomonas elongata. In this work, we explore two complementary approaches to obtain genetically improved producer strains for ectoine production. We explore the effect of increased precursor supply (oxaloacetate) on ectoine production, as well as an implementation of increased ectoine demand through the overexpression of a transporter. Both approaches were implemented on an already genetically modified ectoine-excreting strain H. elongata KB2.13 (ΔteaABC ΔdoeA) and both led to new strains with higher ectoine excretion. The supply driven approach led to a 45% increase in ectoine titers in two different strains. This increase was attributed to the removal of phosphoenolpyruvate carboxykinase (PEPCK), which allowed the conversion of 17.9% of the glucose substrate to ectoine. For the demand driven approach, we investigated the potential of the TeaBC transmembrane proteins from the ectoine-specific Tripartite ATP-Independent Periplasmic (TRAP) transporter as export channels to improve ectoine excretion. In the absence of the substrate-binding protein TeaA, an overexpression of both subunits TeaBC facilitated a three-fold increased excretion rate of ectoine. Individually, the large subunit TeaC showed an approximately five times higher extracellular ectoine concentration per dry weight compared to TeaBC shortly after its expression was induced. However, the detrimental effect on growth and ectoine titer at the end of the process hints toward a negative impact of TeaC overexpression on membrane integrity and possibly leads to cell lysis. By using either strategy, the ectoine synthesis and excretion in H. elongata could be boosted drastically. The inherent complementary nature of these approaches point at a coordinated implementation of both as a promising strategy for future projects in Metabolic Engineering. Moreover, a wide variation of intracelllular ectoine levels was observed between the strains, which points at a major disruption of mechanisms responsible for ectoine regulation in strain KB2.13.
KW - Osmoadaptation
KW - Metabolic engineering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555644
DO - https://doi.org/10.3389/fmicb.2022.968983
SN - 1664-302X
VL - 13
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-55564
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shaheen, Sabahat
A1 - Hicke, Konstantin
T1 - Geometric phase in distributed fiber optic sensing
N2 - The geometric phase in the beat signal from coherent interference of two frequency-offset light beams is measured using a novel distributed optical fiber sensing setup. In a fiber optic medium, with changing beam intensities, to the best of our knowledge, ours is the first measurement of the mentioned geometric phase. Experimental results of applying a 100-Hz sinusoidal stimulus to a polarization scrambler and a piezoelectric transducer inline to an optical fiber are presented. The results may enable novel distributed fiber sensing techniques.
KW - Distributed fiber optic sensing
KW - Geometric phase measurement
KW - Distributed vibration sensing
KW - C-OTDR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556053
DO - https://doi.org/10.1364/OL.464259
VL - 47
IS - 15
SP - 3932
EP - 3935
PB - Optica
CY - Washington D.C., USA
AN - OPUS4-55605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heuser, Lina
A1 - Nofz, Marianne
T1 - Alkali and alkaline earth zinc and lead borate glasses: Structure and properties
N2 - Low melting Li2O-PbO-B2O3, Me2O-ZnO-B2O3, Me = Li, Na, K, Rb and CaO-ZnO-B2O3 glasses were studied with Raman and infrared spectroscopies to advance the structural understanding of zinc borate glasses as potential candidates for substitution of lead containing glasses. Although the effect of type of alkali ions on the number (N4) of fourfold coordinated boron (B4) in the glasses is small, the alkali ions direct the type of borate groups, i.e., pentaborate in lithium, sodium, and calcium zinc borate glasses, as well as diborate in potassium and rubidium containing ones. Both groups were simultaneously found in Li2O-PbO-B2O3. Alkali ions are mainly responsible for the formation of B4-units and metaborate. Zinc ions favorably compensate non-bridging oxygen and partially form ZnO4. With decreasing N4 and field strength of the alkali ions the atomic packing density, glass transition temper ature and Young’s Modulus also decrease. The coefficient of thermal expansion increases with decreasing N4.
KW - Raman spectroscopy
KW - IR spectroscopy
KW - Alkali zinc borate glasses
KW - Lead borate glasses
KW - Physical properties
KW - Young’s Modulus
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556109
DO - https://doi.org/10.1016/j.nocx.2022.100109
SN - 2590-1591
VL - 15
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Klewe, Tim
A1 - Völker, Tobias
A1 - Götz, J.
A1 - Landmann, M.
A1 - Wilsch, Gerd
A1 - Kruschwitz, Sabine
T1 - Sorting of construction and demolition waste by combining LIBS with NIR spectroscopy
N2 - In a joint project of partners from industry and research, the automated recycling of construction and demolition waste (CDW) is investigated and tested by combing laser-induced breakdown spectroscopy (LIBS) and near-infrared (NIR) spectroscopy. Joint processing of information (data fusion) is expected to significantly improve the sorting quality of various materials like concrete, main masonry building materials, organic components, etc., and may enable the detection and separation of impurities such as SO3-cotaining building materials (gypsum, aerated concrete, etc.). The project focuses primarily on the Berlin site to analyze the entire value chain, minimize economic/technological barriers and obstacles at the cluster level, and sustainably increase recovery and recycling rates. First measurements with LIBS and NIR spectroscopy show promising results in distinguishing various material types and indicate the potential for a successful combination. In addition, X-ray fluorescence (XRF) spectroscopy is being performed to obtain more information about the quantitative elemental composition of the different building materials. Future work will apply the developed sorting methodology in a fully automated measurement setup with CDW on a conveyor belt.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - LIBS
KW - NDT
KW - Circular economy
KW - Recycling
KW - Material classification
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555531
UR - http://www.ndt.net/?id=27220
VL - 2022/09
SP - 1
EP - 9
PB - NDT.net
CY - Bad Breisig
AN - OPUS4-55553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paskin, A.
A1 - Couasnon, T.
A1 - Perez, J. P. H.
A1 - Lobanov, S. S.
A1 - Blukis, R.
A1 - Reinsch, Stefan
A1 - Benning, L. G.
T1 - Nucleation and Crystallization of Ferrous Phosphate Hydrate via an Amorphous Intermediate
N2 - The fundamental processes of nucleation and crystallization are widely observed in systems relevant to material synthesis and biomineralization; yet most often, their mechanism remains unclear. In this study, we unravel the discrete stages of nucleation and crystallization of Fe3(PO4)2·8H2O (vivianite). We experimentally monitored the formation and transformation from ions to solid products by employing correlated, time-resolved in situ and ex situ approaches. We show that vivianite crystallization occurs in distinct stages via a transient amorphous precursor phase. The metastable amorphous ferrous phosphate (AFEP) intermediate could be isolated and stabilized. We resolved the differences in bonding environments, structure, and symmetric changes of the Fe site during the transformation of AFEP to crystalline vivianite through synchrotron X-ray absorption spectroscopy at the Fe K-edge. This intermediate AFEP phase has a lower water content and less distorted local symmetry, compared to the crystalline end product vivianite. Our combined results indicate that a nonclassical, hydration-induced nucleation and transformation driven by the incorporation and rearrangement of water molecules and ions (Fe2+ and PO4 3−) within the AFEP is the dominating mechanism of vivianite formation at moderately high to low vivianite supersaturations (saturation index ≤ 10.19). We offer fundamental insights into the aqueous, amorphous-to-crystalline transformations in the Fe2+−PO4 system and highlight the different attributes of the AFEP, compared to its crystalline counterpart.
KW - Nucleation
KW - Crystallization
KW - Vivianite
KW - Ferrous phosphate hydrate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580696
DO - https://doi.org/10.1021/jacs.3c01494
SN - 0002-7863
VL - 145
IS - 28
SP - 15137
EP - 15151
PB - ACS Publications
AN - OPUS4-58069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menero-Valdés, P.
A1 - Chronakis, Michail Ioannis
A1 - Fernández, B.
A1 - Quarles Jr., C. D.
A1 - González-Iglesias, H.
A1 - Meermann, Björn
A1 - Pereiro, R.
T1 - Single Cell–ICP–ToF-MS for the Multiplexed Determination of Proteins: Evaluation of the Cellular Stress Response
N2 - An automated and straightforward detection and data treatment strategy for the determination of the protein relative concentration in individual human cells by single cell–inductively coupled plasma–time-of-flight mass spectrometry (sc-ICP-ToF-MS) is proposed. Metal nanocluster (NC)-labeled specific antibodies for the target proteins were employed, and ruthenium red (RR) staining, which binds to the cells surface, was used to determine the number of cell events as well as to evaluate the relative volume of the cells. As a proof of concept, the expression of hepcidin, metallothionein-2, and ferroportin employing specific antibodies labeled with IrNCs, PtNCs, and AuNCs, respectively, was investigated by sc-ICP-ToF-MS in human ARPE-19 cells. Taking into account that ARPE-19 cells are spherical in suspension and RR binds to the surface of the cells, the Ru intensity was related to the cell volume (i.e., the cell volume is directly proportional to (Ru intensity)3/2), making it possible to determine not only the mass of the target proteins in each individual cell but also the relative concentration. The proposed approach is of particular interest in comparing cell cultures subjected to different supplementations. ARPE-19 cell cultures under two stress conditions were compared: a hyperglycemic model and an oxidative stress model. The comparison of the control with treated cells shows not only the mass of analyzed species but also the relative changes in the cell volume and concentration of target proteins, clearly allowing the identification of subpopulations under the respective treatment.
KW - Peptides and Proteins
KW - Immunology
KW - Metals
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581630
DO - https://doi.org/10.1021/acs.analchem.3c02558
VL - 95
IS - 35
SP - 13322
EP - 13329
PB - ACS Publications
AN - OPUS4-58163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zare Pakzad, S.
A1 - Nasr Esfahani, M.
A1 - Tasdemir, Z.
A1 - Wollschläger, Nicole
A1 - Li, T.
A1 - Li, X.
A1 - Yilmaz, M.
A1 - Leblebici, Y.
A1 - Erdem Alaca, B.
T1 - Nanomechanical Modeling of the Bending Response of Silicon Nanowires
N2 - Understanding the mechanical behavior of silicon nanowires is essential for the implementation of advanced nanoscale devices. Although bending tests are predominantly used for this purpose, their findings should be properly interpreted through modeling. Various modeling approaches tend to ignore parts of the effective parameter set involved in the rather complex bending response. This oversimplification is the main reason behind the spread of the modulus of elasticity and strength data in the literature. Addressing this challenge, a surface-based nanomechanical model is introduced in this study. The proposed model considers two important factors that have so far remained neglected despite their significance: (i) intrinsic stresses composed of the initial residual stress and surface-induced residual stress and (ii) anisotropic implementation of surface stress and elasticity. The modeling study is consolidated with molecular dynamics-based study of the native oxide surface through reactive force fields and a series of nanoscale characterization work through in situ threepoint bending test and Raman spectroscopy. The treatment of the test data through a series of models with increasing complexity demonstrates a spread of 85 GPa for the modulus of elasticity and points to the origins of ambiguity regarding silicon nanowire properties, which are some of the most commonly employed nanoscale building blocks. A similar conclusion is reached for strength with variations of up to 3 GPa estimated by the aforementioned nanomechanical models. Precise consideration of the nanowire surface state is thus critical to comprehending the mechanical behavior of silicon nanowires accurately. Overall, this study highlights the need for a multiscale theoretical framework to fully understand the size-dependent mechanical behavior of silicon nanowires, with fortifying effects on the design and reliability assessment of future nanoelectromechanical systems.
KW - Silicon nanowires
KW - Native oxide
KW - Surface stress
KW - Surface elasticity
KW - Mechanical behavior
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581676
DO - https://doi.org/10.1021/acsanm.3c02077
SP - 1
EP - 14
PB - ACS Publications
AN - OPUS4-58167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ivanov, V.V.
A1 - Tielemann, Christopher
A1 - Avramova, K.
A1 - Reinsch, Stefan
A1 - Tonchev, V.
T1 - Modelling crystallization: When the normal growth velocity depends on the supersaturation
N2 - The crystallization proceeds by the advance of the crystal faces into the disordered phase at the expense of the material excess, the supersaturation. Using a conservation constraint for the transformation ratio α∈[0,1] as complementing the rescaled supersaturation to 1 and a kinetic law for the normal growth velocity as function of the supersaturation raised to power g, the growth order, we derive an equation for the rate of transformation dα/dt. We integrate it for the six combinations of the three spatial dimensions D = 1, 2, 3 and the two canonical values of g = 1, 2 towards obtaining expressions for αDg. The same equation, with g = 1 and D = n (n is the so called Avrami exponent) is obtained when taking only the linear in α term from the Taylor’s expansion around α = 0 of the model equation of Johnson-Mehl-Avrami-Kolmogorov (JMAK). We verify our model by fitting datasets of α21 and α31 (from α = 0 to αupper = 0.999) with JMAK to obtain from the fit n = 1.725, 2.43, resp. We show
further how the values of n depend on the value of αupper to which the fit is performed starting always from 0. Towards building a validation protocol, we start with validating α21 with published results.
KW - Crystallization
KW - Supersaturation
KW - Growth kinetics
KW - Growth rate
KW - JMAK model
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581706
DO - https://doi.org/10.1016/j.jpcs.2023.111542
SN - 0022-3697
VL - 181
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-58170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, A.
A1 - Wegener, T.
A1 - Degener, Sebastian
A1 - Bolender, A.
A1 - Möller, N.
A1 - Niendorf, T.
T1 - Experimental Analysis of the Stability of Retained Austenite in a Low‐Alloy 42CrSi Steel after Different Quenching and Partitioning Heat Treatments
N2 - Quenching and partitioning (Q&P) steels are characterized by an excellent combination of strength and ductility, opening up great potentials for advanced lightweight components. The Q&P treatment results in microstructures with a martensitic matrix being responsible for increased strength whereas interstitially enriched metastable retained austenite (RA) contributes to excellent ductility. Herein, a comprehensive experimental characterization of microstructure evolution and austenite stability is carried out on a 42CrSi steel being subjected to different Q&P treatments. The microstructure of both conditions is characterized by scanning electron microscopy as well as X‐ray diffraction (XRD) phase analysis. Besides macroscopic standard tensile tests, RA evolution under tensile loading is investigated by in situ XRD using synchrotron and laboratory methods. As a result of different quenching temperatures, the two conditions considered are characterized by different RA contents and morphologies, resulting in different strain hardening behaviors as well as strength and ductility values under tensile loading. In situ synchrotron measurements show differences in the transformation kinetics being rationalized by the different morphologies of the RA. Eventually, the evolution of the phase specific stresses can be explained by the well‐known Masing model.
KW - Condensed Matter Physics
KW - General Materials Science
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581618
DO - https://doi.org/10.1002/adem.202300380
SN - 1438-1656
VL - 25
IS - 17
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-58161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arikan, Muzaffer
A1 - Muth, Thilo
T1 - Integrated multi-omics analyses of microbial communities: A review of the current state and future directions
N2 - Integrated multi-omics analyses of microbiomes have become increasingly common in recent years as the emerging omics technologies provide an unprecedented opportunity to better understand the structural and functional properties of microbial communities. Consequently, there is a growing need for and interest in the concepts, approaches, considerations, and available tools for investigating diverse environmental and host-associated microbial communities in an integrative manner. In this review, we first provide a general overview of each omics analysis type, including a brief history, typical workflow, primary applications, strengths, and limitations. Then, we inform on both experimental design and bioinformatics analysis considerations in integrated multi-omics analyses, elaborate on the current approaches and commonly used tools, and highlight the current challenges. Finally, we discuss the expected key advances, emerging trends, potential implications on various fields from human health to biotechnology, and future directions.
KW - Microbiome
KW - Multi-omics
KW - Data integration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580785
DO - https://doi.org/10.1039/d3mo00089c
SP - 1
EP - 17
PB - Royal Society of Chemistry
AN - OPUS4-58078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Walke, D.
A1 - Micheel, D.
A1 - Schallert, K.
A1 - Muth, Thilo
A1 - Broneske, D.
A1 - Saake, G.
A1 - Heyer, R.
T1 - The importance of graph databases and graph learning for clinical applications
N2 - The increasing amount and complexity of clinical data require an appropriate way of storing and analyzing those data. Traditional approaches use a tabular structure (relational databases) for storing data and thereby complicate storing and retrieving interlinked data from the clinical domain. Graph databases provide a great solution for this by storing data in a graph as nodes (vertices) that are connected by edges (links). The underlying graph structure can be used for the subsequent data analysis (graph learning). Graph learning consists of two parts: graph representation learning and graph analytics. Graph representation learning aims to reduce high-dimensional input graphs to low-dimensional representations. Then, graph analytics uses the obtained representations for analytical tasks like visualization, classification, link prediction and clustering which can be used to solve domain-specific problems. In this survey, we review current state-of-the-art graph database management systems, graph learning algorithms and a variety of graph applications in the clinical domain. Furthermore, we provide a comprehensive use case for a clearer understanding of complex graph learning algorithms.
KW - Graph databases
KW - Graph learning
KW - Review
KW - RDF
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580858
DO - https://doi.org/10.1093/database/baad045
SN - 1758-0463
SP - 1
EP - 20
AN - OPUS4-58085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - John, Elisabeth
A1 - Lothenbach, Barbara
ED - Carter, C. B.
T1 - Cement hydration mechanisms through time – a review
N2 - In this article the progress of the research on cement hydration mechanisms is critically reviewed, starting with the work of Le Chatelier and Michaelis during the late 19th century. Proposed mechanisms are discussed in the light of experimental data to highlight the role of new or improved analytical techniques. The focus of this article lies on the dormant period and the silicate reaction.
Today many of the mechanisms proposed throughout time cannot withstand experimental evidence and need to be rejected, including the classical protective hydrate layer theory. However, it seems likely that hydrated surface species are involved in the mechanism. Theories that aim to explain the rate changes solely based on the nucleation and growth of portlandite can also not withstand experimental evidence. Nevertheless, the retardation of portlandite crystal growth through silicate ions is a relevant factor. Especially since it might present a mechanism for the nucleation of calcium silicate hydrate (C-S-H), backing up theories that propose C-S-H and portlandite to grow from the same nuclei.
Finally, an overview over facts, that are currently considered to be valid and hence need to be regarded in future mechanisms is given.
KW - Cement hydration
KW - Calcium silicate hydrate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577460
DO - https://doi.org/10.1007/s10853-023-08651-9
SN - 1573-4803
VL - 58
IS - 24
SP - 9805
EP - 9833
PB - Springer Science + Business Media B.V
CY - Dordrecht [u.a.]
AN - OPUS4-57746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holstein, Tanja
A1 - Kistner, Franziska
A1 - Martens, L.
A1 - Muth, Thilo
T1 - PepGM: A probabilistic graphical model for taxonomic inference of viral proteome samples with associated confidence scores
N2 - Motivation: Inferring taxonomy in mass spectrometry-based shotgun proteomics is a complex task. In multi-species or viral samples of unknown taxonomic origin, the presence of proteins and corresponding taxa must be inferred from a list of identified peptides, which is often complicated by protein homology: many proteins do not only share peptides within a taxon but also between taxa. However, the correct taxonomic inference is crucial when identifying different viral strains with high-sequence homology—considering, e.g., the different epidemiological characteristics of the various strains of severe acute respiratory syndrome-related coronavirus-2. Additionally, many viruses mutate frequently, further complicating the correct identification of viral proteomic samples.
Results: We present PepGM, a probabilistic graphical model for the taxonomic assignment of virus proteomic samples with strain-level resolution and associated confidence scores. PepGM combines the results of a standard proteomic database search algorithm with belief propagation to calculate the marginal distributions, and thus confidence scores, for potential taxonomic assignments. We demonstrate the performance of PepGM using several publicly available virus proteomic datasets, showing its strain-level resolution performance. In two out of eight cases, the taxonomic assignments were only correct on the species level, which PepGM clearly indicates by lower confidence scores.
Availability and implementation: PepGM is written in Python and embedded into a Snakemake workflow. It is available at https://github.com/BAMeScience/PepGM.
KW - Graphical model
KW - Proteomics
KW - Virus
KW - Bayesian model
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577488
SN - 1367-4803
VL - 39
IS - 5
SP - 1
EP - 11
PB - Oxford University Press
CY - Oxford, UK
AN - OPUS4-57748
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
ED - Maldague, X.
T1 - Detection of internal defects applying photothermal super resolution reconstruction utilizing two-dimensional high-power random pixel patterns
N2 - In this work, we report on our progress for investigating a new experimental approach for thermographic detection of internal defects by performing 2D photothermal super resolution reconstruction. We use modern high-power laser projector technology to repeatedly excite the sample surface photothermally with varying spatially structured 2D pixel patterns. In the subsequent (blind) numerical reconstruction, multiple measurements are combined by exploiting the joint-sparse nature of the defects within the specimen using nonlinear convex optimization methods. As a result, a 2D-sparse defect/inhomogeneity map can be obtained. Using such spatially structured heating combined with compressed sensing and computational imaging methods allows to significantly reduce the experimental complexity and to study larger test surfaces as compared to the one-dimensional approach reported earlier.
T2 - Quantitative Infrared Thermography 2022
CY - Paris, France
DA - 04.07.2022
KW - Thermography
KW - Super resolution
KW - NDT
KW - inspection
KW - Internal defects
KW - DMD
KW - DLP
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577795
DO - https://doi.org/10.21611/qirt.2022.1005
SN - 2371-4085
SP - 1
EP - 7
PB - QIRT Council
AN - OPUS4-57779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
A1 - Given, Joseph
A1 - Rentala, V. K.
A1 - Lehleitner, Johannes
A1 - Kanzler, D.
A1 - Heckel, Thomas
A1 - Tkachenko, Viktoriya
T1 - Human Factors in der POD - ist das möglich?
N2 - Menschliche Faktoren sind ein häufig genanntes Thema, wenn wir über
die Zuverlässigkeit der zerstörungsfreien Prüfung (ZfP) sprechen. Die Probability of Detection (POD), das üblicherweise verwendete Maß für die Zuverlässigkeit der ZfP, betrachtet jedoch nur die technische Fähigkeit eines ZfP-Systems, einen Fehler zu entdecken. Nach mehreren Jahrzehnten der Erforschung des Einflusses der menschlichen Faktoren auf die Zuverlässigkeit der ZfP gibt es immer noch keinen allgemein akzeptierten Ansatz, um menschliche Faktoren in der Zuverlässigkeitsbewertung sichtbar zu machen. Dieser Beitrag gibt einen Überblick über verschiedene verfügbare Methoden zur Einbeziehung menschlicher Faktoren in die Zuverlässigkeitsbewertung. Das Thema ist ein essenzieller Bestandteil des laufenden WIPANO-Projekts "normPOD", das sich als Ziel gesetzt hat, die Standardisierung der Zuverlässigkeitsbewertung in Deutschland voranzutreiben und im Vergleich zu den schon bekannten internationalen Normen einen Fokus auf den Umgang mit den menschlichen Faktoren zu legen.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Human factors
KW - Zuverlässigkeit
KW - POD
KW - Probability of detection
KW - Reliability
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559942
SP - 1
EP - 15
AN - OPUS4-55994
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jüngert, A.
A1 - Heckel, Thomas
A1 - Tkachenko, Viktoriya
A1 - Bertovic, Marija
A1 - Vrana, J.
A1 - Kanzler, D.
T1 - POD, aber wie? Konzeption und Herstellung von Testkörpersätzen und Prüfvorschriften für die experimentelle Zuverlässigkeitsbestimmung von ZfP-Prüfansätzen
N2 - Im Rahmen des WIPANO Vorhabens „normPOD“ wird eine Richtlinie zur experimentellen und simulationsgestützten Zuverlässigkeitsbewertung erstellt. In der Richtlinie wird die Zuverlässigkeitsbewertung beispielhaft für zwei praktische Anwendungsfälle vorgestellt. Ein Anwendungsfall beschäftigt sich mit konventionellen Ultraschallprüfungen an ferritischen Stählen und deren
Schweißnähten.
Zur Berechnung von Probability-Of-Detection (POD)-Kurven ist es notwendig, dass ein geeigneter Testkörpersatz zur Verfügung steht, der sowohl leicht zu findende Fehlstellen als auch Fehlstellen, die an der Grenze der Detektierbarkeit liegen, enthält.
Im Vorhaben kommen verschiedene Testkörper zum Einsatz, die entweder Ersatzfehler wie Nuten und Bohrungen oder künstlich eingebrachte realistische Fehlstellen wie Risse und Schweißfehler enthalten.
Zur Erstellung eines möglichst allgemeinen Leitfadens zur Testkörperherstellung für die Zuverlässigkeitsbewertung werden verschiedene Möglichkeiten betrachtet. Es wird ein Testkörpersatz mit Ersatzfehlern hergestellt und durch Testkörper mit realistischen Fehlstellen ergänzt. Mit Hilfe von Simulationen mit CIVA sollen die optimalen Konfigurationen und Anordnung von realistischen Fehlstellen und Ersatzfehlern identifiziert, und anschließend mithilfe geeigneter Fertigungsverfahren eingebracht und validiert werden. Neben den Testkörpern, die gezielt für das Vorhaben hergestellt werden, kommen außerdem kommerziell erhältliche Testkörpersätze mit realistischen Fehlstellen zum Einsatz.
Die Prüfaussage einer Ultraschallprüfung hängt weiterhin wesentlich von den Informationen ab, die dem Prüfpersonal vor Ort zur Verfügung steht. Es muss ein ausgewogenes Maß zwischen zu wenig und zu viel Informationen gefunden werden.
Im letzten Schritt wird deshalb eine geeignete Vorlage für eine Prüfanweisung erstellt, die so formuliert ist, dass die Wahrscheinlichkeit menschlicher Fehler (z. B. Missverständnis, Fehlinterpretation, Überspringen von Schritten usw.) möglichst gering ist.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Zuverlässigkeit
KW - POD
KW - Testkörper
KW - Ultraschallprüfung
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560103
SP - 1
EP - 9
AN - OPUS4-56010
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, D.
A1 - Rentala, V. K.
A1 - Bertovic, Marija
A1 - Heckel, Thomas
A1 - Tkachenko, Viktoriya
A1 - Given, Joseph
A1 - Keßler, S.
A1 - Dethof, F.
A1 - Jüngert, A.
A1 - Vrana, J.
T1 - Lasst uns mal POD standardisieren!
N2 - Seit beinahe 50 Jahren werden Zuverlässigkeitsbewertungen zerstörungsfreier Prüfverfahren erfolgreich in unterschiedlichen Industriebranchen eingesetzt. Dennoch gibt es weiterhin viele Vorbehalte, da die Bewertungsgrundlage nicht standardisiert ist und konkrete Handlungsanweisungen fehlen. Dem gegenüber steht die Anerkennung in der ZfP-Community. Es ist bisher nur Wenigen bekannt, dass dem Wissen über die Zuverlässigkeit eines zerstörungsfreien Prüfverfahren eineSchlüsselfunktion für die ZfP 4.0 zukommt.
Im Vortrag wird die Notwendigkeit für eine Norm oder eine Richtlinie zum Thema Zuverlässigkeitsbewertungen aufgezeigt. Es wird darauf eingegangen, warum es bisher (in Deutschland) noch keine Richtlinie gab und gibt und was der:die Anwender:innen aus einer Richtlinie zur Zuverlässigkeitsbewertung von ZfP-Prüfverfahren erwarten kann.
Es werden konkrete Schritte und Vorgehensweisen zur Bewertung der Zuverlässigkeit eines Verfahrens aufgezeigt; von der Definition eines Anwendungsfalls, über die Herstellung geeigneter Testkörper bis hin zur Durchführung und Bewertung von Prüfungen unter Einbeziehung von menschlichen Einflüssen. Die Beispiele umfassen sowohl Anwendungen aus dem Bauwesen als auch aus dem Maschinen- und Anlagenbau.
Der Vortrag fasst die bisherigen und geplanten Arbeiten in dem WIPANO Projekt „Normung für die probabilistische Bewertung der Zuverlässigkeit für zerstörungsfreie Prüfverfahren“ zusammen.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Zuverlässigkeit
KW - POD
KW - Probability of detection
KW - Reliability
KW - Human Factors
KW - Simulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560113
SP - 1
EP - 10
AN - OPUS4-56011
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
A1 - Given, Joseph
A1 - Lehleitner, Johannes
T1 - First insights into the human-related risks of tunnel inspection
N2 - Whereas human factors (HF) in the non-destructive testing (NDT) of metallic components are a poorly investigated topic (in comparison to other industrial fields such as aviation), HF in the inspection of concrete components are even less known. Studies have shown that there is always some variability between individuals in their inspection results and that HF affect the reliability of NDT inspections. The aim of the ongoing WIPANO project is to draft a standard for a holistic reliability assessment, with concrete inspection as one case study. This includes also the HF. A human-oriented Failure Modes and Effects Analysis (FMEA) was carried out to do the following: a) identify possible human-related risks in tunnel inspection processes using a laser scan method (including data collection,evaluation, and assessment of tunnel damage) and b) evaluate these human-related risks as regards their possible causes, consequences and probability of occurrence – in addition with respect to existing and possible preventive measures. The results show that the causes for possible failures can lie within people, the physical environment, technology, organisation, and extra-organisational environment. Whereas current preventive measures rely mostly on the individual and quality management practices, there is potential for even larger improvement at the organisational and extra-organisational level. The FMEA results were also used to develop a quantification method to further understand the HF in tunnel inspection, which could possibly be included in the information into the overall reliability assessment. The usage of qualitative and quantitative data collected through the human-FMEA within the proposed quantification method shows promise that HF can be quantified and could offer broader understanding of HF influences on inspection in various industries
T2 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Human Factors
KW - Failure Modes and Effects Analysis
KW - FMEA
KW - Tunnel Inspection
KW - NDT Reliability
KW - Quantification
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560138
SP - 1
EP - 5
AN - OPUS4-56013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Griesche, Axel
A1 - Pfretzschner, Beate
A1 - Taparli, Ugur Alp
A1 - Kardjilov, N.
T1 - Time-Resolved Neutron Bragg-Edge Imaging: A Case Study by Observing Martensitic Phase Formation in Low Temperature Transformation (LTT) Steel during GTAW
N2 - Polychromatic and wavelength-selective neutron transmission radiography were applied during bead-on-plate welding on 5 mm thick sheets on the face side of martensitic low transformation temperature (LTT) steel plates using gas tungsten arc welding (GTAW). The in situ visualization of austenitization upon welding and subsequent α’-martensite formation during cooling could be achieved with a temporal resolution of 2 s for monochromatic imaging using a single neutron wavelength and of 0.5 s for polychromatic imaging using the full spectrum of the beam (white beam).
The spatial resolution achieved in the experiments was approximately 200 µm. The transmitted monochromatic neutron beam intensity at a wavelength of λ = 0.395 nm was significantly reduced during cooling below the martensitic start temperature M s since the emerging martensitic phase has a ~10% higher attenuation coefficient than the austenitic phase. Neutron imaging was significantly influenced by coherent neutron scattering caused by the thermal motion of the crystal lattice (Debye–Waller factor), resulting in a reduction in the neutron transmission by approx. 15% for monochromatic and by approx. 4% for polychromatic imaging.
KW - Neutron radiography
KW - Debye–Waller factor
KW - Austenite-to-martensite transformation
KW - Low transformation temperature (LTT) steel
KW - Bragg-edge imaging
KW - Gas tungsten arc welding (GTAW)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559077
DO - https://doi.org/10.3390/app112210886
VL - 11
IS - 22
PB - MDPI
AN - OPUS4-55907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herr, M.
A1 - Borras, F. X.
A1 - Spaltmann, Dirk
A1 - Kröll, Mirco
A1 - Pirker, F.
A1 - Cihak-Bayr, U.
T1 - How to create trusted tribological characterization data of soft polymers as input for FEM simulations?
N2 - Soft polymers such as the investigated polyurethane, characterized by low Young’s moduli and prone to high shear deflection, are frequently applied in pneumatic cylinders. Their performance and lifetime without external lubrication are highly determined by the friction between seal and shaft and the wear rate. FEM simulation has established itself as a tool in seal design processes but requires input values for friction and wear depending on material, load, and velocity. This paper presents a tribological test configuration for long stroke, reciprocating movement, allowing the generation of data which meet the requirements of input parameters for FEM simulations without the geometrical influences of specific seal profiles. A numerical parameter study, performed with an FEM model, revealed the most eligible sample geometry as a flat, disc-shaped sample of the polymer glued on a stiff sample holder. At the same time, the study illustrates that the sensitivity of the contact pressure distribution to Poisson’s ratio and CoF can be minimized by the developed and verified setup. It ensures robust, reliable, and repeatable experimental results with uniform contact pressures and constant contact areas to be used in databases and FEM simulations of seals, enabling upscaling from generically shaped samples to complex seal profiles.
KW - Tribologie
KW - FEM
KW - Simulation
KW - Polymere
KW - Charakterisierung
KW - i-TRIBOMAT
KW - Modellierung
KW - Polyurethan
KW - Dichtungen
KW - Upscaling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567683
DO - https://doi.org/10.3390/ma16010131
SN - 1996-1944
VL - 16
IS - 1
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-56768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherr, J. F.
A1 - Kollofrath, J.
A1 - Popovics, J. S.
A1 - Bühling, Benjamin
A1 - Grosse, C. U.
T1 - Detection of Delaminations in Concrete Plates Using a Laser Ablation Impact Echo Technique
N2 - This study investigates the non-destructive detection of delaminations in concrete plates using non-contact laser ablation, instead of the conventional hammer excitation, as part of the impact echo method. We performed tests on five concrete specimens of different sizes, two of which contained artificial delaminations. A range of steel ball hammers was used as reference impulse sources, the responses of which were compared with wave excitation generated by a 7 ns pulsed 1064 nm Nd:YAG laser with 150 mJ pulse energy. Signals were recorded by surface-mounted accelerometers and two contactless methods: microphones and a laser Doppler vibrometer. The laser generates frequencies across a broad range of frequencies (0 to 150 kHz) but with much less energy than the hammers' narrower frequency spectra; the laser pulse energy transferred into the specimen is 0.07 mJ, corresponding to about 0.5 ‰ of the impulse source energy. Because of this, the thick intact plates' characteristic thickness stretch resonance frequency can be reliably detected by the hammer excitations but not when using laser excitation. However, the laser can excite low-frequency flexural vibration modes over a shallow delamination at 3 cm depth. The low-frequency flexural vibration results are verified by numerical natural frequency analysis.
KW - Concrete testing
KW - Defect detection
KW - Lamb waves
KW - Impact echo
KW - Non-destructive testing
KW - Vibration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567932
DO - https://doi.org/10.1007/s10921-022-00921-x
SN - 0195-9298
VL - 42
IS - 1
SP - 1
EP - 14
PB - Springer
AN - OPUS4-56793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chubarenko, B.
A1 - Domnin, D.
A1 - Simon, Franz-Georg
A1 - Scholz, Philipp
A1 - Leitsin, V.
A1 - Tovpinets, A.
A1 - Karmanov, K.
A1 - Esiukova, E.
T1 - Change over Time in theMechanical Properties of Geosynthetics Used in Coastal Protection in the South-Eastern Baltic
N2 - The most massive design on the Baltic shore used geosynthetic materials, the landslide protection construction in Svetlogorsk (1300 m long, 90,000 m2 area, South-Eastern Baltic, Kaliningrad Oblast, Russian Federation) comprises the geotextile and the erosion control geomat coating the open-air cliff slopes. Due to changes in elastic properties during long-term use in the open air, as well as due to its huge size, this structure can become a non-negligible source of microplastic pollution in the Baltic Sea. Weather conditions affected the functioning of the structure, so it was assessed that geosynthetic materials used in this outdoor (open-air) operation in coastal protection structures degraded over time. Samples taken at points with different ambient conditions (groundwater outlet; arid places; exposure to the direct sun; grass cover; under landslide) were tested on crystallinity and strain at break. Tests showed a 39–85% loss of elasticity of the polymer filaments after 3 years of use under natural conditions. Specimens exposed to sunlight are less elastic and more prone to fail, but not as much as samples taken from shaded areas in the grass and under the landslide, which were the most brittle.
KW - Geosynthetics
KW - Microplastic
KW - Degradation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567978
UR - https://www.mdpi.com/2077-1312/11/1/113
DO - https://doi.org/10.3390/jmse11010113
SN - 2077-1312
VL - 11
IS - 1
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-56797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martusevich, A.
A1 - Kornev, R.
A1 - Ermakov, A.
A1 - Gornushkin, Igor B.
A1 - Nazarov, V.
A1 - Shabarova, L.
A1 - Shkrunin, V.
T1 - Spectroscopy of Laser-Induced Dielectric Breakdown Plasma in Mixtures of Air with Inert Gases Ar, He, Kr, and Xe
N2 - The generation of ozone and nitrogen oxides by laser-induced dielectric breakdown (LIDB) in mixtures of air with noble gases Ar, He, Kr, and Xe is investigated using OES and IR spectroscopy, mass spectrometry, and absorption spectrophotometry. It is shown that the formation of NO and NO2 noticeably depends on the type of inert gas; the more complex electronic configuration and the lower ionization potential of the inert gas led to increased production of NO and NO2. The formation of ozone occurs mainly due to the photolytic reaction outside the gas discharge zone. Equilibrium thermodynamic analysis showed that the formation of NO in mixtures of air with inert gases does not depend on the choice of an inert gas, while the equilibrium concentration of the NO+ ion decreases with increasing complexity of the electronic configuration of an inert gas.
KW - Laser-induced dielectric breakdown (LIDB)
KW - Nitrogen monoxide
KW - Nitrogen dioxide
KW - Ozone
KW - Emission spectroscopy
KW - Inert gases
KW - Thermodynamic analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568258
DO - https://doi.org/10.3390/s23020932
SN - 1424-8220
VL - 23
IS - 2
SP - 1
EP - 13
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-56825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shaheen, Sabahat
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Phase-sensitive optical time domain reflectometry based on geometric phase measurement
N2 - A phase-sensitive optical time domain reflectometer based on coherent heterodyne detection of geometric phase in the beat signal of light, is reported for the first time to our knowledge. The use of the geometric phase to extract strain makes it immune to polarisation diversity fading. This is because a polarisation mismatch between the interfering beams is not a hindrance to its measurement. The geometric phase is calculated using the amplitude of the beat signal and individual beam intensities without any need for phase unwrapping. It is measured per beat period and can be equated with the traditionally measured dynamic phase with appropriate scaling. The results show that the system based on the geometric phase successfully measures strain, free from polarisation mismatch fading and phase unwrapping errors, providing a completely novel solution to these problems.
KW - Fiber optic sensing
KW - Distributed acoustic sensing
KW - DAS
KW - Geometric phase
KW - Pancharatnam–Berry phase
KW - Berry phase
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570307
DO - https://doi.org/10.1038/s41598-023-29972-4
VL - 13
SP - 1
EP - 11
PB - Nature Portfolio
CY - London
AN - OPUS4-57030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 1. Where is the Bragg angle?
N2 - The derivation of a crystal structure and its phase-specific parameters from a single wide-angle backscattered Kikuchi diffraction pattern requires reliable extraction of the Bragg angles. By means of the first derivative of the lattice profile, an attempt is made to determine fully automatically and reproducibly the band widths in simulated Kikuchi patterns. Even under such ideal conditions (projection centre, wavelength and lattice plane traces are perfectly known), this leads to a lattice parameter distribution whose mean shows a linear offset that correlates with the mean atomic number Z of the pattern-forming phase. The consideration of as many Kikuchi bands as possible reduces the errors that typically occur if only a single band is analysed. On the other hand, the width of the resulting distribution is such that higher image resolution of diffraction patterns, employing longer wavelengths to produce wider bands or the use of higher interference orders is less advantageous than commonly assumed.
KW - Bragg angles
KW - Kikuchi bands
KW - Kikuchi patterns
KW - First derivative
KW - Lattice parameters
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573141
DO - https://doi.org/10.1107/S1600576723000134
SN - 0021-8898
VL - 56
IS - Pt. 2
SP - 349
EP - 360
AN - OPUS4-57314
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 2. Offset corrections
N2 - A band width determination using the first derivative of the band profile systematically underestimates the true Bragg angle. Corrections are proposed to compensate for the resulting offset Δa/a of the mean lattice parameters derived from as many Kikuchi band widths as possible. For dynamically simulated Kikuchi patterns, Δa/a can reach up to 8% for phases with a high mean atomic number Z, whereas for much more common low-Z materials the offset decreases linearly. A predicted offset Δa/a = f(Z) is therefore proposed, which also includes the unit-cell volume and thus takes into account the packing density of the scatterers in the material. Since Z is not always available for unknown phases, its substitution by Zmax, i.e. the atomic number of the heaviest element in the compound, is still acceptable for an approximate correction. For simulated Kikuchi patterns the offset-corrected lattice parameter deviation is Δa/a < 1.5%. The lattice parameter ratios, and the angles α, β and γ between the basis vectors, are not affected at all.1.5%. The lattice parameter ratios, and the angles � , � and � between the basis vectors, are not affected at all.
KW - Mean atomic number
KW - Kikuchi patterns
KW - Lattice parameters
KW - Automated Bragg angle determination
KW - Lattice parameter determination
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573153
DO - https://doi.org/10.1107/s1600576723000146
SN - 0021-8898
VL - 56
IS - Pt. 2
SP - 361
EP - 366
AN - OPUS4-57315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Rychlowski, L.
T1 - Use of electron backscatter diffraction patterns to determine the crystal lattice. Part 3. Pseudosymmetry
N2 - A pseudosymmetric description of the crystal lattice derived from a single wideangle Kikuchi pattern can have several causes. The small size (<15%) of the sector covered by an electron backscatter diffraction pattern, the limited precision of the projection centre position and the Kikuchi band definition are crucial. Inherent pseudosymmetries of the crystal lattice and/or structure also pose a challenge in the analysis of Kikuchi patterns. To eliminate experimental errors as much as possible, simulated Kikuchi patterns of 350 phases have been analysed using the software CALM [Nolze et al. (2021). J. Appl. Cryst. 54, 1012–1022] in order to estimate the frequency of and reasons for pseudosymmetric crystal lattice descriptions. Misinterpretations occur in particular when the atomic scattering factors of non-equivalent positions are too similar and reciprocal-lattice points are systematically missing. As an example, a pseudosymmetry prediction depending on the elements involved is discussed for binary AB compounds with B1 and B2 structure types. However, since this is impossible for more complicated phases, this approach cannot be directly applied to compounds of arbitrary composition and structure.
KW - Bravais lattices
KW - Pseudosymmetry
KW - Lattice point density
KW - Ordered/disordered structures
KW - Lattice distortion
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573169
DO - https://doi.org/10.1107/s1600576723000845
SN - 0021-8898
VL - 56
IS - Pt. 2
SP - 367
EP - 380
AN - OPUS4-57316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mazumdar, Tilottama
A1 - Bartholomäus, A.
A1 - McMahon, Dino Peter
ED - Rokas, A.
T1 - Draft Genome of the Entomopathogenic Fungus Metarhizium robertsii DSM 1490
N2 - Metarhizium robertsii DSM 1490 is a generalist entomopathogenic fungus.
The mechanisms of pathogenesis of such fungi in insects like termites are not completely understood. Here, we report the draft genome sequence, as sequenced on the Oxford Nanopore platform. The genome has a GC% of 47.82 and a size of 45,688,865 bp
KW - Draft Genome
KW - Entomopathogenic Fungus
KW - Metarhizium robertsii DSM 1490
KW - Mechanisms of pathogenesis
KW - Infecting a number of insects,
KW - Close proximity to colonies
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573186
DO - https://doi.org/10.1128/mra.01267-22
SN - 2576-098X
VL - 2023
SP - 1
EP - 2
PB - ASM Journals
CY - Nashville, USA
AN - OPUS4-57318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
T1 - Accessing radiation damage to biomolecules on the nanoscale by particle-scattering simulations
N2 - Radiation damage to DNA plays a central role in radiation therapy to cure cancer. The physico-chemical and biological processes involved encompass huge time and spatial scales. To obtain a comprehensive understanding on the nano and the macro scale is a very challenging tasks for experimental techniques alone. Therefore particle-scattering simulations are often applied to complement measurements and aide their interpretation, to help in the planning of experiments, to predict their outcome and to test damage models. In the last years, powerful multipurpose particle-scattering framework based on the Monte-Carlo simulation (MCS) method, such as Geant4 and Geant4-DNA, were extended by user friendly interfaces such as TOPAS and TOPAS-nBio. This shifts their applicability from the realm of dedicated specialists to a broader range of scientists. In the present review we aim to give an overview over MCS based approaches to understand radiation interaction on a broad scale, ranging from cancerous tissue, cells and their organelles including the nucleus, mitochondria and membranes, over radiosensitizer such as metallic nanoparticles, and water with additional radical scavenger, down to isolated biomolecules in the form of DNA, RNA, proteins and DNA-protein complexes. Hereby the degradation of biomolecules by direct damage from inelastic scattering processes during the physical stage, and the indirect damage caused by radicals during the chemical stage as well as some parts of the early biological response is covered. Due to their high abundance the action of hydroxyl radicals (•OH) and secondary low energy electrons (LEE) as well as prehydrated electrons are covered in additional detail. Applications in the prediction of DNA damage, DNA repair processes, cell survival and apoptosis, influence of radiosensitizer on the dose distribution within cells and their organelles, the study of linear energy transfer (LET), the relative biological effectiveness (RBE), ion beam cancer therapy, microbeam radiation therapy (MRT), the FLASH effect, and the radiation induced bystander effect are reviewed.
KW - DNA
KW - Protein
KW - G5P
KW - OH
KW - Au
KW - AuNP
KW - Radiation
KW - SSB
KW - DSB
KW - Beta decay
KW - Brachytherapy
KW - Cancer treatment
KW - Clustered nanoparticles
KW - DNA damage
KW - Dosimetry
KW - Energy deposit
KW - Geant4
KW - Geant4-DNA
KW - Gold Nanoparticles
KW - Livermore model
KW - Low energy electrons
KW - MCS
KW - Microdosimetry
KW - Monte-Carlo simulation
KW - NP
KW - OH radical
KW - Particle scattering
KW - Penelope model
KW - Proteins
KW - Radiation damage
KW - Radiation therapy
KW - Radiationtherapy
KW - Radioactive decay
KW - Radiolysis
KW - Radiotherapy
KW - Simulation
KW - TOPAS
KW - TOPAS-nbio
KW - Base damage
KW - Base loss
KW - DNA radiation damage
KW - Direct damage
KW - Dissociative electron attachment (DEA)
KW - Dissociative electron transfer (DET)
KW - Double-strand break (DSB)
KW - ESCA
KW - Hydrated DNA
KW - Hydrated electron
KW - Hydration shell
KW - Hydroxyl radical
KW - Indirect damage
KW - Ionization
KW - Ionisation
KW - NAP-XPS
KW - Near ambient pressure xray photo electron spectroscopy
KW - Net-ionization reaction
KW - Prehydrated electron
KW - Presolvated electron
KW - Quasi-direct damage
KW - ROS
KW - Radical
KW - Reactive oxygen species
KW - Single-strand break (SSB)
KW - XPS
KW - Xray
KW - Xray photo electron spectrocopy
KW - Cosolute
KW - Ectoin
KW - Ectoine
KW - GVP
KW - Gene five protein
KW - Hydroxyectoine
KW - Ionizing radiation damage
KW - OH radical scavenger
KW - Monte-Carlo simulations
KW - Nanodosimetry
KW - Osmolyte
KW - Particle scattering simulations
KW - Protein unfolding
KW - Radical Scavenge
KW - Radical scavenger
KW - Single-stranded DNA-binding proteins
KW - SAXS
KW - Bio-SAXS
KW - X-ray scattering
KW - ssDNA
KW - dsDNA
KW - FLASH effect
KW - Bystander effect
KW - Ion beam therapy
KW - Bragg peak
KW - LET
KW - MCNP
KW - Photons
KW - Electrons
KW - Carbon ions
KW - MRT
KW - RNA
KW - RBE
KW - base loss
KW - abasic side
KW - DMSO
KW - Cells
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573240
DO - https://doi.org/10.1088/2399-6528/accb3f
SN - 2399-6528
VL - 7
IS - 4
SP - 042001
PB - Institute of Physics (IOP) Publishing
CY - London
AN - OPUS4-57324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Barzegar, M.
A1 - Pasadas, D. J.
A1 - Ribeiro, A. L.
A1 - Ramos, H. G.
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
T1 - Polar Coordinate for Damage Imaging of Adhesively Bonded Plates Using Ultrasonic Guided Waves and Laser Doppler Vibrometer Measurements
N2 - Wavefield measurements by a scanning laser Doppler vibrometer are generally carried out in a cartesian coordinate. As a piezoelectric transducer generates Lamb waves following radial paths, the use of a polar coordinate can be a suitable alternative to the use of a cartesian coordinate. Therefore, in the proposed method, using a single transducer placed on the center of the specimen, the measured wavefields are transformed into polar coordinates, making several identical radial line inspections from the center in a direction of incident waves. Taking advantage of the properties of the polar coordinates, a signal processing technique is proposed through a frequency-wavenumber filtering process in these coordinates. In this technique, by using proper filters, unwanted wave modes of the incident wave along with all reflected waves are filtered out. In addition, the conventional features of RMS and Euclidean distance are adapted for the polar coordinate system to image the bonded plate. The proposed signal processing and damage imaging are first introduced through a numerical simulation. Then, the performance of the proposed technique is presented by experimental measurements of two specimens including adhesively bonded carbon fiber-reinforced plastic composite plates and bonded aluminum plates.
KW - Lamb waves
KW - Composites
KW - Disbond
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573386
DO - https://doi.org/10.1109/TIM.2023.3267528
SN - 0018-9456
VL - 72
SP - 1
EP - 11
PB - IEEE
CY - Piscataway Township, New Jersey, USA
AN - OPUS4-57338
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Rosner, M.
A1 - Cipriani, A.
A1 - Frick, D. A.
A1 - Glodny, J.
A1 - Hoffmann, E. J.
A1 - Hora, J. M.
A1 - Irrgeher, J.
A1 - Lugli, F.
A1 - Magna, T.
A1 - Meisel, T. C.
A1 - Meixner, A.
A1 - Possolo, A.
A1 - Pramann, A.
A1 - Pribil, M. J.
A1 - Prohaska, T.
A1 - Retzmann, Anika
A1 - Rienitz, O.
A1 - Rutherford, D.
A1 - Paula-Santos, G. M.
A1 - Tatzel, M.
A1 - Widhalm, S.
A1 - Willbold, M.
A1 - Zuliani, T.
A1 - Vogl, Jochen
T1 - Characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study
N2 - An interlaboratory comparison (ILC)was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the so-called conventional method for determining 87Sr/86Sr isotope ratios. Four cements (VDZ 100a,VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG CGL ML-3) and one slate (IAG OU-6) reference materials were selected, covering a wide range of naturally occurring Sr isotopic signatures. Thirteen laboratories received aliquots of these six reference materials together with a detailed technical protocol. The consensus values for the six reference materials and their associated measurement uncertainties were obtained by applying a Gaussian, linear mixed effects model fitted to all the measurement results. By combining the consensus values and their uncertainties with an uncertainty contribution for potential heterogeneity, reference values ranging from 0.708134 mol mol-1 to 0.729778 mol mol-1 were obtained with relative expanded uncertainties of ≤ 0.007 %. This study represents an ILC on conventional 87Sr/86Sr isotope ratios, within which metrological principles were considered and the compatibility of measurement results obtained by MC-ICP-MS and by MC-TIMS is demonstrated. The materials characterised in this study can be used as reference materials for validation and quality control purposes and to estimate measurement uncertainties in conventional 87Sr/86Sr isotope ratio measurement.
KW - Sr isotope analysis
KW - Isotope ratios
KW - Cement
KW - Geological material
KW - MC-TIMS
KW - MC-ICP-MS
KW - Interlaboratory comparison
KW - Measurement uncertainty
KW - Cconventional method
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579836
DO - https://doi.org/10.1111/ggr.12517
SN - 1639-4488
VL - 47
IS - 4
SP - 821
EP - 840
PB - Wiley online library
AN - OPUS4-57983
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nxumalo, T.
A1 - Akhdhar, A.
A1 - Mueller, V.
A1 - Simon, Fabian
A1 - von der Au, Marcus
A1 - Cossmer, Antje
A1 - Pfeifer, Jens
A1 - Krupp, E.
A1 - Meermann, Björn
A1 - Kindness, A.
A1 - Feldmann, J.
T1 - EOF and target PFAS analysis in surface waters affected by sewage treatment effluents in Berlin, Germany
N2 - Per- and polyfuoroalkyl substances (PFAS) are emerging organic pollutants and can occur in surface and groundwater. To identify the degree of pollution in surface water with PFAS, often targeted HPLC–ESI–MS/MS has been employed in which commonly 30–40 compounds are analyzed. However, other PFAS and organofuorines remain undetected. We sampled surface water of the river Spree and the Teltow Canal in Berlin, Germany, which are afected by the efuent discharge of wastewater treatment plants. Here, we employed high-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) for measuring extractable organofuorines (EOF) and compared in a mass balance approach the total fuorine to the identifed and quantifed PFAS from the targeted analysis. The analysis highlights that the EOF are in the range expected for an urban river system (Winchell et al. in Sci Total Environ 774, 2021). However, downstream of an efuent discharge, the EOF increased by one order of magnitude, e.g., 40.3 to 574 ng F L−1, along the Teltow Canal. From our target analytes, mostly short-chained perfuorinated carboxylic acids and sulfonates occur in the water, which however makes up less than 10% of the EOF. The increase in EOF in the Teltow Canal correlates well with the increase of perfuorohexanoic acid (PFHxA), indicating that PFHxA is characteristic for the discharged EOF but not responsible for the increase. Hence, it points to PFHxA precursor discharge. The study highlights that EOF screening using HR-CS-GFMAS is necessary to identify the full scale of pollution with regard to PFAS and other organofuorines such as pharmaceutical compounds from the efuent of WWTPs.
KW - PFAS
KW - WWTP
KW - GF-MAS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580341
DO - https://doi.org/10.1007/s00216-022-04500-x
VL - 415
SP - 1195
EP - 1204
PB - Springer
AN - OPUS4-58034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hendriks, L.
A1 - Brunjes, R.
A1 - Taskula, S.
A1 - Kocic, J.
A1 - Hattendorf, B.
A1 - Bland, G.
A1 - Lowry, G.
A1 - Bolea-Fernandez, E.
A1 - Vanhaecke, F.
A1 - Wang, J.
A1 - Baalousha, M.
A1 - von der Au, Marcus
A1 - Meermann, Björn
A1 - Holbrook, T.
A1 - Wagner, S.
A1 - Harycki, S.
A1 - Gundlach-Graham, A.
A1 - von der Kammer, F.
T1 - Results of an interlaboratory comparison for characterization of Pt nanoparticles using single-particle ICP-TOFMS
N2 - This study describes an interlaboratory comparison (ILC) among nine (9) laboratories to evaluate and validate the standard operation procedure (SOP) for single-particle (sp) ICP-TOFMS developed within the context of the Horizon 2020 project ACEnano. The ILC was based on the characterization of two different Pt nanoparticle (NP) suspensions in terms of particle mass, particle number concentration, and isotopic composition. The two Pt NP suspensions were measured using icpTOF instruments (TOFWERK AG, Switzerland).
Two Pt NP samples were characterized and mass equivalent spherical sizes (MESSs) of 40.4 ± 7 nm and 58.8 ± 8 nm were obtained, respectively. MESSs showed <16% relative standard deviation (RSD) among all participating labs and <4% RSD after exclusion of the two outliers. A good agreement was achieved between the different participating laboratories regarding particle mass, but the particle number concentration results were more scattered, with <53% RSD among all laboratories, which is consistent with results from previous ILC studies conducted using ICP-MS instrumentation equipped with a sequential mass spectrometer. Additionally, the capabilities of sp-ICP-TOFMS to determine masses on a particle basis are discussed with respect to the potential for particle density determination. Finally, because quasi-simultaneous multi-isotope and multielement determinations are a strength of ICP-TOFMS instrumentation, the precision and trueness of isotope ratio determinations were assessed. The average of 1000 measured particles yielded a precision of below ±1% for intensity ratios of the most abundant Pt isotopes, i.e. 194Pt and 195Pt, while the accuracy of isotope ratios with the lower abundant isotopes was limited by counting statistics.
KW - ILC
KW - spICP-MS
KW - PtNP
KW - Nanopartikel
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580353
DO - https://doi.org/10.1039/d3nr00435j
SN - 2040-3364
VL - 15
IS - 26
SP - 11268
EP - 11279
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Thomas, P.
T1 - Phase Error Evaluation via Differentiation and Cross-Multiplication Demodulation in Phase-Sensitive Optical Time-Domain Reflectometry
N2 - Phase-sensitive optical time-domain reflectometry (jOTDR) is a technology for distributed vibration sensing, where vibration amplitudes are determined by recovering the phase of the backscattered light. Measurement noise induces phase errors, which degrades sensing performance. The phase errors, using a differentiation and cross-multiplication (DCM) algorithm, are investigated theoretically and experimentally in a jOTDR system based on a phase retrieval configuration consisting of an imbalanced Mach–Zehnder interferometer (IMZI) and a 3 x 3 coupler. Analysis shows that phase error is highly dependent on the AC component of the obtained signal, essentially being inversely proportional to the product of the power of the light backscattered from two locations. An analytical expression was derived to estimate the phase error and was confirmed by experiment. When applied to the same measurement data, the error is found to be slightly smaller than that obtained using in-phase/quadrature (I/Q) demodulation. The error, however, increases for longer measurement times.
KW - Distributed fiber sensing
KW - Phase-sensitive optical time-domain reflectometry
KW - Phase error
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580501
UR - https://www.mdpi.com/2304-6732/10/5/514
DO - https://doi.org/10.3390/photonics10050514
SN - 2304-6732
VL - 10
IS - 5
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-58050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gong, M.
A1 - Mehmood, Asad
A1 - Ali, B.
A1 - Nam, K.-W.
A1 - Kucernak, A.
T1 - Oxygen Reduction Reaction Activity in Non-Precious Single-Atom (M−N/C) Catalysts − Contribution of Metal and Carbon/Nitrogen Framework-Based Sites
N2 - We examine the performance of a number of single-atom M−N/C electrocatalysts with a common structure in order to deconvolute the activity of the framework N/C support from the metal M−N4 sites in M−N/Cs. The formation of the N/C framework with oordinating nitrogen sites is performed using zinc as a templating agent. After the formation of the electrically conducting carbon−nitrogen metal-coordinating network, we (trans)metalate with different metals producing a range of different catalysts (Fe−N/C, Co−N/C, Ni−N/C, Sn−N/C, Sb−N/C, and Bi−N/C) without the formation of any metal particles. In these materials, the structure of the carbon/nitrogen framework remains unchanged-only the coordinated metal is substituted. We assess the performance of the subsequent catalysts in acid, near-neutral, and alkaline environments toward the oxygen reduction reaction (ORR) and ascribe and quantify the performance to a combination of metal site activity and activity of the carbon/nitrogen framework. The ORR activity of the carbon/nitrogen framework is about 1000-fold higher in alkaline than it is in acid, suggesting a change in mechanism. At 0.80 VRHE, only Fe and Co contribute ORR activity significantly beyond that provided by the carbon/nitrogen framework at all pH values studied. In acid and near-neutral pH values (pH 0.3 and 5.2, respectively), Fe shows a 30-fold improvement and Co shows a 5-fold improvement, whereas in alkaline pH (pH 13), both Fe and Co show a 7-fold improvement beyond the baseline framework activity. The site density of the single metal atom sites is estimated using the nitrite adsorption and stripping method. This method allows us to deconvolute the framework sites and metal-based active sites. The framework site density of catalysts is estimated as 7.8 × 1018 sites g−1. The metal M−N4 site densities in Fe−N/C and Co−N/C are 9.4 × 1018 sites−1 and 4.8 × 1018 sites g−1, respectively.
KW - Active site density
KW - Fuel cells
KW - Single-atom catalysts
KW - Oxygen reduction reaction
KW - PGM-free catalysts
KW - M−N/Cs
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575640
DO - https://doi.org/10.1021/acscatal.3c00356
SN - 2155-5435
VL - 13
IS - 10
SP - 6661
EP - 6674
PB - American Chemical Society
AN - OPUS4-57564
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lengas, Nikolaos
A1 - Müller, Karsten
A1 - Schlick-Hasper, Eva
A1 - Neitsch, Marcel
A1 - Johann, Sergej
A1 - Zehn, M. W.
T1 - Improved criteria for evaluating impact targets in regulative drop tests of dangerous goods packagings
N2 - For dangerous goods packagings, drop testing onto an essential unyielding target can be used to assess the mechanical resistance to impact loads. Adopted regulations like ADR/RID require that the impact surface provided shall be integral with a mass at least 50 times than that of the heaviest package to be tested. The problem is that many manufacturers do not possess impact targets that satisfy the required 50 times mass ratio for regulative drop tests during series production. The objective of this work is to verify existing and define improved criteria for impact target structures based on systematic investigations. Previous evidence highlights the relevance of other parameters in addition to the mass ratio. Therefore, in this research, a variation of drop test parameters was carried out experimentally. Furthermore, numerical vibration analysis was applied to investigate the deformability of the impact surface. The results conclude that the mass ratio of 1:50 cannot be defined as a decisive criterion. In order to determine the influence of further drop test parameters, the research findings were used to validate a parametric model which assesses impact target deflection. An approximation quality of over 90 % was achieved. As a result, new evaluation criteria are proposed. Firstly, a method for identifying critical impact target designs is provided. Secondly, a new comprehensive formula compares the approximated maximum deflection of a real impact target to the respective theoretical threshold derived from a worst-case assumption. In practice, this leads to great advantages in the evaluation of already installed impact targets for dangerous goods packagings.
KW - Corrugated fibreboard box
KW - Dangerous goods packagings
KW - Drop test
KW - Impact target
KW - Mechanical response
KW - Steel drum
KW - Structural dynamics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576985
DO - https://doi.org/10.1002/pts.2759
SN - 0894-3214
SP - 1
EP - 14
PB - John Wiley & Sons Ltd
AN - OPUS4-57698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obaton, A.-F.
A1 - Fain, J.
A1 - Meinel, Dietmar
A1 - Tsamos, Athanasios
A1 - Léonard, F.
A1 - Lécuelle, B.
A1 - Djemaï, M.
T1 - In Vivo Bone Progression in and around Lattice Implants Additively Manufactured with a New Titanium Alloy
N2 - The osseointegration in/around additively manufactured (AM) lattice structures of a new titanium alloy, Ti–19Nb–14Zr, was evaluated. Different lattices with increasingly high sidewalls gradually closing them were manufactured and implanted in sheep. After removal, the bone–interface implant (BII) and bone–implant contact (BIC) were studied from 3D X-ray computed tomography images. Measured BII of less than 10 µm and BIC of 95% are evidence of excellent osseointegration.
Since AMnaturally leads to a high-roughness surface finish, the wettability of the implant is increased.
The new alloy possesses an increased affinity to the bone. The lattice provides crevices in which the biological tissue can jump in and cling. The combination of these factors is pushing ossification beyond its natural limits. Therefore, the quality and speed of the ossification and osseointegration in/around these Ti–19Nb–14Zr laterally closed lattice implants open the possibility of bone spline key of prostheses. This enables the stabilization of the implant into the bone while keeping the possibility of punctual hooks allowing the implant to be removed more easily if required. Thus, this new titanium alloy and such laterally closed lattice structures are appropriate candidates to be implemented in a new generation of implants.
KW - Osseointegration
KW - X-ray computed tomography
KW - Additive manufacturing
KW - Machine learning segmentation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577066
DO - https://doi.org/10.3390/app13127282
VL - 13
IS - 12
SP - 1
EP - 18
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-57706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michail Ioannis, Chronakis
A1 - von der Au, Marcus
A1 - Meermann, Björn
T1 - Single cell-asymmetrical flow field-flow fractionation/ICP-time of flight-mass spectrometry (sc-AF4/ICP-ToF-MS): an efficient alternative for the cleaning and multielemental analysis of individual cells
N2 - Asymmetrical Flow Field-Flow Fractionation (AF4), as a cleaning technique, was combined on-line with the multielemental analytical capabilities of an Inductively Coupled Plasma-Time of Flight-Mass Spectrometer (ICP-ToF-MS). In that manner, the heavy ionic matrix effect of untreated cells' samples can be significantly reduced. As a proof of concept, commercial baker's yeast cells were analysed.
KW - AF4
KW - Single Cell
KW - Cleaning
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576419
DO - https://doi.org/10.1039/d2ja00264g
SN - 0267-9477
VL - 37
IS - 12
SP - 2691
EP - 2700
PB - Royal Society of Chemistry
AN - OPUS4-57641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amano, K. O. A.
A1 - Hahn, S.-K.
A1 - Butt, N.
A1 - Vorwerk, P.
A1 - Gimadieva, E.
A1 - Tschirschwitz, Rico
A1 - Rappsilber, Tim
A1 - Krause, U.
T1 - Composition and Explosibility of Gas Emissions from Lithium-Ion Batteries Undergoing Thermal Runaway
N2 - Lithium-based batteries have the potential to undergo thermal runaway (TR), during which mixtures of gases are released. The purpose of this study was to assess the explosibility of the gaseous emission from LIBs of an NMC-based cathode during thermal runaway. In the current project, a series of pouch lithium-based battery cells was exposed to abuse conditions (thermal) to study the total amount of gases released and the composition of the gas mixture. First, the battery cells were placed in a closed vessel, and the pressure and temperature rise inside the vessel were measured. In a second step, the composition of gases was analysed using a Fourier transform Infrared (FTIR) spectrometer.
We found that the amount of released gases was up to 102 ± 4 L, with a clear dependence on the battery capacity. This study showed that the concentration of gaseous emissions such as carbon monoxide (CO), methane (CH4), ethylene (C2H4), ethane (C2H6), and hydrogen cyanide (HCN) increased with higher cell capacity. Of the five studied flammable gases, the maximum concentrations of carbon monoxide (16.85 vol%), methane (7.6 vol%), and ethylene (7.86 vol%) were identified to be within their explosible range. Applying Le Chatelier’s law, a calculated lower explosion limit (LEL) of 7% in volume fraction was obtained for the gas mixture. The upper explosion limit (UEL) of the gas mixture was also found to be 31% in volume. A filter comprising pyrobubbles was used for the removal of the studied gas components released during the thermal abuse. The investigation revealed that the pyrobubbles filter was highly effect in the removal of HCN (up to 94% removal) and CO2 (up to 100% removal). Herein, we report the dependency of the method of thermal runaway trigger on the measured maximum temperature.
KW - Lithium-ion battery
KW - Thermal runaway
KW - Smoke gas emission
KW - Gas explosion
KW - Explosion limit
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576477
DO - https://doi.org/10.3390/batteries9060300
VL - 9
IS - 6
SP - 1
EP - 19
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-57647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Bethke, John
A1 - Goedecke, Thomas
T1 - How To Measure The Angle of Repose of Hazardous Substances in the Test Centers for Dangerous Goods Packagings
N2 - The flow properties of powdery or granular filling substances for dangerous goods packagings are safety-relevant parameters. To specify the flow behavior, the angle of repose is measured in the recognized test centers for dangerous goods packagings in Germany. Previous investigations performed on non-hazardous substances revealed that some of the methods currently used have disadvantages in application. Additionally, for occupational health and safety reasons, it was generally viewed critically to carry out measurements of the angle of repose for dangerous goods at all. Instead, the dimensionless Hausner ratio to describe the flow behavior was proposed.
In this work, the investigations were extended to real hazardous substances to concretize the assessment. Five exemplary hazardous substances were tested for their angle of repose using the methods commonly applied in the test centers. The Hausner ratio was also determined. In addition, the influence of a different climatic preconditioning on the angle of repose measurement was examined using three selected non-hazardous bulk materials.
The results show that the measurement of the angle of repose is not fundamentally excluded for dangerous goods. However, for reasons of applicability, repeatability and occupational health and safety, only the ISO method can be applied for dangerous filling substances. This method provides conservative results regarding a safety-related evaluation of flow properties for the transport of dangerous goods.
In principle, both the ISO method and the determination of the Hausner ratio can be used for dangerous goods. It is also essential especially with finely powdered filling goods, to carry out controlled preconditioning.
KW - Angle of repose
KW - Flow properties
KW - Flowability
KW - Hausner ratio
KW - Powders
KW - Sift-proofness
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576552
DO - https://doi.org/10.1002/pts.2756
SN - 0894-3214
SP - 1
EP - 20
PB - Wiley
AN - OPUS4-57655
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Sokolowski‐Tinten, Klaus
T1 - Probing Laser‐Driven Structure Formation at Extreme Scales in Space and Time
N2 - Irradiation of solid surfaces with high intensity, ultrashort laser pulses triggers a variety of secondary processes that can lead to the formation of transient and permanent structures over a large range of length scales from mm down to the nano‐range. One of the most prominent examples are LIPSS – Laser‐Induced Periodic Surface Structures. While LIPSS have been a scientific evergreen for of almost 60 years, experimental methods that combine ultrafast temporal with the required nm spatial resolution have become available only recently with the advent of short pulse, short wavelength free electron lasers. Here, the current status and future perspectives in this field are discussed by exploiting the unique possibilities of these 4th‐generation light sources to address by time‐domain experimental techniques the fundamental LIPSS‐question, namely why and how laser irradiation can initiate the transition of a “chaotic” (rough) surface from an aperiodic into a periodic structure.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Free electron laser
KW - Pump-probe experiments
KW - Time-resolved scattering
KW - Capillary waves
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595048
DO - https://doi.org/10.1002/lpor.202300912
SN - 1863-8899
VL - 18
SP - 1
EP - 11
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-59504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keshmiri, Hamid
A1 - Cikes, Domagoj
A1 - Samalova, Marketa
A1 - Schindler, Lukas
A1 - Appel, Lisa-Marie
A1 - Urbanek, Michal
A1 - Yudushkin, Ivan
A1 - Slade, Dea
A1 - Weninger, Wolfgang J.
A1 - Peaucelle, Alexis
A1 - Penninger, Josef
A1 - Elsayad, Kareem
T1 - Brillouin light scattering anisotropy microscopy for imaging the viscoelastic anisotropy in living cells
N2 - Maintaining and modulating mechanical anisotropy is essential for biological processes. However, how this is achieved at the microscopic scale in living soft matter is not always clear. Although Brillouin light scattering (BLS) spectroscopy can probe the mechanical properties of materials, spatiotemporal mapping of mechanical anisotropies in living matter with BLS microscopy has been complicated by the need for sequential measurements with tilted excitation and detection angles. Here we introduce Brillouin light scattering anisotropy microscopy (BLAM) for mapping high-frequency viscoelastic anisotropy inside living cells. BLAM employs a radial virtually imaged phased array that enables the collection of angle-resolved dispersion in a single shot, thus enabling us to probe phonon modes in living matter along different directions simultaneously. We demonstrate a precision of 10 MHz in the determination of the Brillouin frequency shift, at a spatial resolution of 2 µm. Following proof-of-principle experiments on muscle myofibres, we apply BLAM to the study of two fundamental biological processes. In plant cell walls, we observe a switch from anisotropic to isotropic wall properties that may lead to asymmetric growth. In mammalian cell nuclei, we uncover a spatiotemporally oscillating elastic anisotropy correlated to chromatin condensation. Our results highlight the role that high-frequency mechanics can play in the regulation of diverse fundamental processes in biological systems. We expect BLAM to find diverse applications in biomedical imaging and material characterization.
KW - Optical and magnetic materials
KW - Atomic and molecular physics and optics
KW - Electronic
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595125
DO - https://doi.org/10.1038/s41566-023-01368-w
SN - 1749-4885
SN - 1749-4893
VL - 18
IS - 3
SP - 276
EP - 285
PB - Nature Publ. Group
CY - London
AN - OPUS4-59512
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schuberth, Jens
A1 - Ebert, Thomas
A1 - Schlegel, Moritz-Caspar
A1 - Rödig, Lisa
A1 - Jepsen, Dirk
A1 - Memelink, Robin
A1 - Hauschke, Fynn
T1 - The Front-Runner Approach - Facilitating Progressive Product Policy by Using Information from EU Product Databases
N2 - The European Commission has recently announced two guiding principles for EU product policy: First, product policy shall ensure that the performance of front-runner products in terms of sustainability becomes the norm, and second, the effectiveness of the current Ecodesign legislative framework is going to be significantly improved. Within this paper, already existing front-runner approaches and recent and ongoing product policy-making processes were reviewed. Based on the results, an EU front-runner approach is outlined. The presented approach (i) refers to performance levels of the best products already available on the market, (ii) aggregates information in existing databases, and (iii) works semi-automated. Together, all three attributes have a high potential to facilitate and accelerate the specification of appropriate minimum requirements for products at the EU level. This way, EU policymakers can deliver on the core objectives of the Ecodesign legislative framework much better. The basic mechanism and its legal entrenchment of the approach are illustrated for the energy efficiency of energy-related products. In addition, the Front-Runner Approach can be applied to any product group in the scope of the upcoming Ecodesign for Sustainable Products Regulation and to a wide range of product-related minimum requirements, such as durability, reparability, or recycled content. The study’s objective is to suggest a tailor-made and dynamic approach to keep the EU product legislation up to date using innovative technology based on the investigation of current regulations and identify the gap. Experiences from three international case studies suggest that a front-runner approach to setting energy-performance standards can drive innovation and reduce energy consumption via promoting energy-efficient products; transparency about available products is one of the key factors and can be established by a database. The EU front-runner approach comprises extending the existing energy label database (or making use of the digital product passport) and introducing a legislative procedure that triggers changes in the energy efficiency requirements in the specific EU regulations if the database shows that a certain threshold value is reached. Challenges such as limited EU staff capacities and opportunities such as increased dynamic are discussed.
KW - Ecodesign
KW - ESPR
KW - Energy labelling
KW - EPREL
KW - Policy making
KW - Front-runner
KW - Material efficiency
KW - Resource efficiency
KW - Energy efficiency
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595132
DO - https://doi.org/10.3390/en17020504
VL - 17
IS - 2
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-59513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Slotyuk, Lyubov
A1 - Part, Florian
A1 - Schlegel, Moritz-Caspar
A1 - Akkerman, Floris
T1 - Life Cycle Assessment of the Domestic Micro Heat and Power Generation Proton Exchange Membrane Fuel Cell in Comparison with the Gas Condensing Boiler Plus Electricity from the Grid
N2 - The energy demand of private households contributes globally to 36.5% of the total CO2 emissions. To analyze the emissions reduction potential, we conducted a comparative life cycle assessment of a proton exchange membrane fuel cell in a residential application and a conventional system with a stand-alone gas condensing boiler and electricity from a grid mix. The period under review was referred to as the service life of the PEMFC and is assumed to be 10 years (83,038 h of PEMFC). The applicability of this in a single-family house built between 1991 and 2000 under German climatic conditions was investigated. The functional unit is set to the thermal energy demand of 16,244 kWh/a and electricity demand of 4919 kWh/a of a single-family house. The impact assessment method “CML 2001–August 2016” was used in this investigation. The manufacturing phase of the proton exchange membrane fuel cell showed disadvantages, whereby the use phase had significant advantages in most of the environmental impact categories as compared to the conventional energy supply system. Considering the whole life cycle, the advantages from the use phase could outperform the disadvantages from the manufacturing phase in most of the impact categories, except for ADP elements and TETP.
KW - Sustainability
KW - Circular Economy
KW - Comparative life cycle assessment
KW - Proton exchange membrane fuel cell
KW - Gas condensing boiler
KW - Micro heat and power generation
KW - Residential application
KW - Single-family house energy supply system
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598134
DO - https://doi.org/10.3390/su16062348
VL - 16
IS - 6
SP - 1
EP - 16
PB - MDPI AG
AN - OPUS4-59813
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Küttenbaum, Stefan
A1 - Kainz, C.
A1 - Braml, T.
T1 - Reliability assessment of existing concrete bridges with geometrical NDT results - Case studies
N2 - The results of and the validity in reliability assessment of existing bridges essentially depend on the information available about the considered system. Information about the actual condition as well as structural and material characteristics can be observed on-site to refine the computation models used in assessment. Non-destructive testing (NDT) methods for concrete structures are capable of reconstructing missing, questioned, or inconsistent as-built plans. This contribution summarizes recent developments within the scope of the national pre-standardization project “ZfPStatik”, which aims to prepare a guideline about NDT-supported structural analyses. The focus is on the purposeful and explicit utilization of geometrical tendon and reinforcement bar positions (measured on-site using the ultrasound echo and ground penetrating radar (GPR) techniques) in probabilistic reliability analyses — shown by means of real case studies. The well-established first order reliability method is applied to different concrete bridges, which are typical for the German road bridge stock, to demonstrate the utility of incorporating quality-evaluated NDT-results in terms of changes in structural reliability.
T2 - 13th German-Japanese Bridge Symposium
CY - Osaka, Japan
DA - 28.08.2023
KW - Non-destructive testing
KW - Prestressed concrete
KW - Data-informed reliability analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582727
SP - 29
EP - 40
PB - Osaka Metropolitan University
CY - Osaka
AN - OPUS4-58272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Retzmann, Anika
A1 - Faßbender, Sebastian
A1 - Rosner, M.
A1 - von der Au, Marcus
A1 - Vogl, Jochen
T1 - Performance of second generation ICP-TOFMS for (multi-)isotope ratio analysis: a case study on B, Sr and Pb and their isotope fractionation behavior during the measurements
N2 - The performance of second generation ICP-TOFMS, equipped with a micro-channel plate (MCP) enabling multi-isotope detection, in terms of isotope ratio precision and instrumental isotopic fractionation (IIF) for (multi-)isotope ratio analysis was thoroughly assessed for B, Sr and Pb. Experimental isotope ratio precision of 0.14 % for 11B/10B intensity ratio, 0.15 % for 87Sr/86Sr intensity ratio and 0.07% for 208Pb/206Pb intensity ratio were obtained at high signal levels ($500 mg L−1) which is comparable to first generation ICP-TOFMS. The long-term stability of isotope ratios, measured over several hours and expressed as repeatability, is between 0.05 % and 1.8 % for B, Sr and Pb. The observed IIF per mass unit is negative for B (i.e., −11 % for 11B/10B) which is in accordance with measurements using sector field (MC) ICP-MS. But the observed IIF per mass unit is positive for Sr (i.e., 2 % for 87Sr/86Sr) and Pb (i.e., 4.5 % for 208Pb/206Pb) which is not in accordance with measurements using sector field (MC) ICP-MS. Furthermore, different IIFs per mass unit were observed for different isotope pairs of the same isotopic system (i.e., Sr, Pb) and adjacent isotopic systems (i.e., Pb vs. Tl). This and the observations from three-isotope plots for Sr and Pb show that ion formation, ion extraction, ion transmission, ion separation and ion detection in second generation ICP-TOFMS is subject to IIF that does not follow the known mass dependent fractionation laws and is possibly caused by mass independent fractionation and/or multiple (contradictory) fractionation processes with varying contributions. The non-mass dependent IIF behavior observed for second generation ICP TOFMS has profound consequences for the IIF correction of isotope raw data, including application of multi-isotope dilution mass spectrometry (IDMS) using ICP-TOFMS. Hence, only IIF correction models that correct also for mass independent fractionation are applicable to calculate reliable isotope ratios using second generation ICP-TOFMS. In the present study, reliable d11B values, and absolute B, Sr and Pb isotope ratios could be determined using the SSB approach in single-element solutions as well as in a mixture of B, Sr and Pb, where the isotopes were measured simultaneously.
KW - ICP-TOFMS
KW - Isotope delta value
KW - Isotope amount ratio
KW - Conventional isotope ratio
KW - Instrumental isotope fractionation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582239
DO - https://doi.org/10.1039/d3ja00084b
SN - 0267-9477
VL - 38
IS - 10
SP - 2144
EP - 2158
PB - Royal Society of Chemistry
AN - OPUS4-58223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shaheen, Sabahat
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Blast-Assisted Subsurface Characterisation Using a Novel Distributed Acoustic Sensing Setup Based on Geometric Phases
N2 - A novel DAS setup based on geometric phases in coherent heterodyne detection is applied for the first time to the characterisation of the Earth’s subsurface. In addition, an optimisation of the proposed setup in terms of its spatial resolution is also presented for the first time. The surface waves are generated by strong blasts of 25 kg of explosives at a dedicated test site. A 10 km dark fiber link in the vicinity of the test site connected to the test setup records the resulting strain signals. The spike-free and low-noise strain data thus obtained minimize post-processing requirements, making the setup a candidate for real-time seismic monitoring. An analysis of the dispersion characteristics of the generated surface waves is performed using a recently reported optimised seismic interferometric technique. Based on the dispersion characteristics, the shear wave velocities of the surface waves as a function of the depth profile of the Earth’s crust are determined using an optimised evolutionary algorithm.
KW - Geophysics
KW - Geometric Phase
KW - Distributed Fiber Optic Sensor
KW - Distributed Acoustic Sensing
KW - Earthquake Monitoring
KW - Seismology
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591913
DO - https://doi.org/10.3390/s24010030
VL - 24
IS - 1
SP - 1
EP - 12
PB - MDPI
AN - OPUS4-59191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Scholz, Philipp
T1 - Assessment of the Long-Term Leaching Behavior of Incineration Bottom Ash: A Study of Two Waste Incinerators in Germany
N2 - The long-term leaching behavior of incineration bottom ash (IBA) was studied with large-scale samples from two German waste incinerators with grate technology. The observation period was up to 281 days. The aging processes proceeded faster in the outdoor storage of the samples. The dominant factor in the leaching behavior is the pH, which starts at values above 12 and decreases to values below 10 (outdoors, <11 indoors). Most heavy metals exhibit minimum solubility in this pH range. The solubility of Sb depends on the prevailing Ca concentration, due to the formation of low-soluble Ca antimonate. The very low sulfate concentrations observed in the leaching tests with fresh IBA could be explained by the presence of ettringite. In the course of the aging reaction, ettringite is transformed into gypsum. The results from batch tests were compared with those from column tests, showing reasonable agreement. Leaching dynamics can be better followed with column tests. All results confirm that the use of IBA is possible under German law.
KW - Aging
KW - Incineration bottom ash
KW - Leaching
KW - Secondary building materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591599
DO - https://doi.org/10.3390/app132413228
SN - 2076-3417
VL - 13
IS - 24
SP - 1
EP - 15
PB - MDPI AG
CY - Basel
AN - OPUS4-59159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Häusler, F.
A1 - Stührenberg, J.
A1 - Neumann, Patrick P.
ED - Sigalov, K.
ED - Hagedorn, P.
ED - Schönfelder, P.
ED - Faltin, B.
ED - Zentgraf, S.
ED - Block, M.
T1 - Gasquellenlokalisierung mit Drohnenschwärmen
N2 - Gasquellenlokalisierungen (Gas Source Localization, GSL) tragen dazu bei, die Folgen von Industrieunfällen und Naturkatastrophen zu mildern. Während die GSL, wenn von Menschen durchgeführt, gefährlich und zeitaufwändig ist, können Schwärme von wendigen und kostengünstigen Nanodrohnen die Effizienz und Sicherheit der Suche erhöhen. Da die geringe Nutzlast von Nanodrohnen die Sensor- und Rechenressourcen einschränkt, werden Strategien zur Koordination des Roboterschwarms verwendet, die von biologischen Schwärmen, wie Kolonien sozialer Insekten, inspiriert sind. Die meisten Schwarm-GSL-Strategien verwenden das Maximum der Gaskonzentrationsverteilung zur Schätzung der Gasquellenposition. Experimente legen jedoch nahe, dass die Intermittenz der Gasverteilung vielversprechender ist. In diesem Beitrag wird eine neuartige GSL-Strategie für Schwärme vorgestellt, die auf Pheromonkommunikation und Intermittenz der Gasverteilung basiert. Die Agenten, d.h. die Nanodrohnen, emittieren Pheromonmarker in einer virtuellen Umgebung, wenn sie eine neue Gaswolke feststellen. Die Agenten werden durch virtuelle Kräfte gesteuert und nutzen abwechselnd das Wissen des Schwarms, indem sie dem Pheromongradienten folgen, oder erkunden den Suchraum, indem sie einen Zufallspunkt ansteuern. Zur Kollisionsvermeidung werden die Agenten durchgehend von anderen Agenten und Wänden abgestoßen. Die Strategie wurde auf drei Nanodrohnen implementiert und durch ein Experiment in einem Innenraum mit einer statischen Gasquelle validiert. Die Ergebnisse zeigen eine Verbesserung gegenüber maximabasierten Verfahren und geringe Lokalisierungsfehler in Windrichtung.
T2 - 34. Forum Bauinformatik 2023
CY - Bochum, Germany
DA - 06.08.2023
KW - Mobile Robotic Olfaction
KW - Bouts
KW - Mobile Sensorik
KW - Nanodrohnen
KW - Pheromonkommunikation
KW - Schwarmrobotik
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594320
DO - https://doi.org/10.13154/294-10088
SP - 168
EP - 175
AN - OPUS4-59432
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Temgoua, Ranil C.T.
A1 - Dontsi, Fabiola T.
A1 - Lebègue, Estelle
A1 - Thobie-Gautier, Christine
A1 - Tonlé, Ignas K.
A1 - Boujtita, Mohammed
T1 - Understanding the behavior of phenylurazole-tyrosine-click electrochemical reaction using hybrid electroanalytical techniques
N2 - In this work, the electrochemical behavior of 4-phenylurazole (Ph-Ur) was studied and the latter was used as a molecular anchor for the electrochemical bioconjugation of tyrosine (Y). Cyclic voltammetry (CV) and controlled potential coulometry (CPC) allowed the in-situ generation of the PTAD (4-phenyl-3 H-1,2,4-triazole-3,5(4 H)-dione) species from phenylurazole on demand for tyrosine electrolabeling. The chemoselectivity of the reaction was studied with another amino acid (lysine, Lys) and no changes in Lys were observed. To evaluate the performance of tyrosine electrolabeling, coulometric analyses at controlled potentials were performed on solutions of phenylurazole and the phenylurazole-tyrosine mixture in different proportions (2:1, 1:1, and 1:2). The electrolysis of the phenylurazole-tyrosine mixture in the ratio (1:2) produced a charge of 2.07 C, very close to the theoretical value (1.93 C), with high reaction kinetics, a result obtained here for the first time. The products obtained were identified and characterized by liquid chromatography coupled to high-resolution electrospray ionization mass spectrometry (LC-HRMS and LC- HRMS2). Two products were formed from the click reactions, one of which was the majority. Another part of this work was to study the electrochemical degradation of the molecular anchor 4-phenylazole (Ph-Ur). Four stable degradation products of phenylurazole were identified (C7H9N2O, C6H8N, C6H8NO, C14H13N4O2) based on chromatographic profiles and mass spectrometry results. The charge generated during the electrolysis of phenylurazole (two-electron process) (2.85 C) is inconsistent with the theoretical or calculated charge (1.93 C), indicating that secondary/parasitic reactions occurred during the electrolysis of the latter. In conclusion, the electrochemically promoted click phenylurazole-tyrosine reactions give rise to click products with high reaction kinetics and yields in the (1:2) phenylurazole-tyrosine ratios, and the presence of side reactions is likely to affect the yield of the click phenylurazole-tyrosine reaction.
KW - Clinical Biochemistry
KW - Spectroscopy
KW - Drug Discovery
KW - Pharmaceutical Science
KW - Analytical Chemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599267
DO - https://doi.org/10.1016/j.jpba.2024.116147
VL - 245
SP - 1
EP - 8
PB - Elsevier BV
AN - OPUS4-59926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirtsch, Mona
T1 - Adoption of the information security management system standard ISO/IEC 27001 - A study among German organizations
N2 - Against the backdrop of numerous security breaches and cyber-attacks, organizations need to take measures to secure their data and information. However, the well-known management system standard ISO/IEC 27001 for information security has shown a lower adoption rate – in terms of annual ISO survey data – than was previously expected by scholars and practitioners. Through the lens of Rogers' diffusion of innovation theory, we consider the adoption of ISO/IEC 27001 as a 'preventive innovation' and aim to identify factors that help gain a better understanding of its adoption. Therefore, we conducted a survey among German organizations on the use and impact of management system standards, explicitly distinguishing between organizations that implement ISO/IEC 27001 and those that are additionally certified against this standard. This study provides insights and contributes to an advanced understanding of motives, impacts, barriers, and useful measures to increase adoption of ISO/IEC 27001. Our findings may be useful to organizations considering the adoption of this management system standard, to certification bodies providing certification services, and to policymakers seeking means to improve information security in organizations.
KW - Management science and operations research
KW - ISO/IEC 27001
KW - Management system standard
KW - Information security
KW - QI-FoKuS
KW - Certification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594704
UR - http://ijqr.net/paper.php?id=1098
DO - https://doi.org/10.24874/ijqr17.03-08
SN - 1800-6450
SN - 1800-7473
VL - 17
IS - 3
SP - 747
EP - 768
PB - Center for Quality, University of Montenegro
CY - Podgorica
AN - OPUS4-59470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaytsev, D.
A1 - Funk, Alexander
T1 - On the crack evolutional in human dentin under uniaxial compression imaged by high resolution tomography
N2 - An observation of the fracture process in front of the crack tip inside a dentin sample by means of ex-situ X-ray computed tomography after uniaxial compression at different deformation values was carried out in this work. This ex-situ approach allowed the microstructure and fracturing process of human dentin to be observed during loading. No cracks are observed up to the middle part of the irreversible deformation in the samples at least visible at 0.4μm resolution. First cracks appeared before the mechanical stress reached the compression strength. The growth of the cracks is realized by connecting the main cracks with satellite cracks that lie ahead of the main crack tip and parallel its trajectory. When under the stress load the deformation in the sample exceeds the deformation at the compression strength of dentin, an appearance of micro-cracks in front of the main cracks is observed. The micro-cracks are inclined (~60°) to the trajectory of the main cracks. The further growth of the main cracks is not realized due to the junction with the micro-cracks; we assume that the micro-cracks dissipate the energy of the main crack and suppressed its growth. These micro-cracks serve as additional stress accommodations, therefore the samples do not break apart after the compression test, as it is usually observed under bending and tension tests.
KW - Dentin
KW - Crack evolution
KW - Compression strength
KW - Mechanical properties
KW - Microstructure
KW - Ex-situ X-ray computed tomography
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594810
DO - https://doi.org/10.18149/MPM.5152023_5
SN - 1605-8119
VL - 51
IS - 5
SP - 38
EP - 51
PB - Advanced Study Center
CY - St. Petersburg
AN - OPUS4-59481
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asna Ashari, Parsa
A1 - Blind, Knut
T1 - The effects of hydrogen research and innovation on international hydrogen trade
N2 - Climate change and the pressure to decarbonize, as well as energy security concerns, have drawn the attention of policymakers and the industry to hydrogen energy. To ad-vance the hydrogen economy at a global scale, research and innovation progress is of significant importance, among others. However, previous studies have provided only lim-ited quantitative evidence of the effects of research and innovation on the formation of a global hydrogen market. Instead, they postulate rather than empirically support this rela-tionship. Therefore, this study analyzes the effects of research and innovation measured by scientific publications, patents, and standards on bilateral hydrogen trade flows for 32 countries between 1995 and 2019 in a gravity model of trade, using regression analyses and Poisson Pseudo Maximum Likelihood (PPML) estimation. The main results of the PPML estimation show that research and innovation progress is indeed associated with increased trade, especially with patenting and (international) standardization enhancing hydrogen export volumes. As policy implications, we derive that increased public R&D funding can help increase the competitiveness of hydrogen energy and boost market growth, along with infrastructure support and harmonized standards and regulations.
KW - Hydrogen supply
KW - Global hydrogen market
KW - Research and innovation
KW - Push and pull effects
KW - Hydrogen policies
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594875
DO - https://doi.org/10.1016/j.enpol.2023.113974
SN - 0301-4215
VL - 186
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-59487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andreoli, A. F.
A1 - Fantin, Andrea
A1 - Kasatikov, S.
A1 - Bacurau, V. P.
A1 - Widom, M.
A1 - Gargarella, P.
A1 - Mazzer, E. M.
A1 - Woodcock, T. G.
A1 - Nielsch, K.
A1 - Coury, F. G.
T1 - The impact of chemical short-range order on the thermophysical properties of medium- and high-entropy alloys
N2 - The unusual behavior observed in the coefficient of thermal expansion and specific heat capacity of CrFeNi, CoCrNi, and CoCrFeNi medium/high-entropy alloys is commonly referred to as the K-state effect. It is shown to be independent of the Curie temperature, as demonstrated by temperature-dependent magnetic moment measurements. CoCrFeNi alloy is chosen for detailed characterization; potential reasons for the K-state effect such as texture, recrystallization, and second-phase precipitation are ruled out. An examination of the electronic structure indicates the formation of a pseudo-gap in the Density of States, which suggests a specific chemical interaction between Ni and Cr atoms upon alloying. Hybrid Monte Carlo/Molecular Dynamic (MC/MD) simulations indicate the presence of non-negligible chemical short-range order (CSRO). Local lattice distortions are shown to be negligible, although deviations around Cr and Ni elements from those expected in a fully disordered structure are experimentally observed by X-ray absorption spectroscopy. The determined bonding distances are in good agreement with MC/MD calculations. A mechanism is proposed to explain the anomalies and calorimetric experiments and their results are used to validate the mechanism.
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595869
DO - https://doi.org/10.1016/j.matdes.2024.112724
SN - 0264-1275
VL - 238
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-59586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Törne, Wipert Jannik
A1 - Steinhäuser, Lorin
A1 - Klyk-Seitz, Urszula-Anna
A1 - Piechotta, Christian
T1 - High-resolution mass spectrometric elucidation of electron ionization induced fragmentation pathways of methylated warfarin and selected hydroxylated species
N2 - The plant secondary metabolite families of coumarin and 4-hydroxy coumarin have a broad pharmacological spectrum ranging from antibacterial to anticancer properties. One prominent member of this substance class is the synthetic but naturally inspired anticoagulant drug and rodenticide warfarin (coumadin). A vast number of publications focus on the identification of warfarin and its major cytochrome P450-mediated phase I metabolites by liquid chromatography (LC) with mass spectrometry (MS) and tandem mass spectrometric (MS/MS) detection techniques. For the first time, electron ionization (EI) induced high-resolution quadrupole time-of-flight mass spectrometric (HR-qToF-MS) data of in-liner derivatized warfarin and selected hydroxylated species is provided in this study as an alternative to LC-MS/MS approaches. Furthermore, the characteristic fragments and fragmentation pathways of the analyzed methyl ethers are concluded. The obtained data of analytical standards, specific deuterated and 13C-labeled compounds prove inductive cleavage of the acyl or acetonyl side chain, methyl migration, and H-migration, along with consequential inductive cleavage as predominant fragmentation routes. Based on the HR-spectral data, commonalities and differences between the analyzed compounds and fragment groups were evaluated with future applicability in structure elucidation and spectra prediction of related compounds.
KW - High-resolution mass spectrometry
KW - Warfarin
KW - Hydroxy warfarin
KW - Fragmentation pathway
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596025
DO - https://doi.org/10.1016/j.ijms.2024.117220
SN - 1387-3806
VL - 499
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-59602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Törne, Wipert Jannik
A1 - Klyk-Seitz, Urszula-Anna
A1 - Piechotta, Christian
T1 - Developing a GC-EI-MS/MS method for quantifying warfarin and five hydroxylated metabolites generated by the Fenton reaction
N2 - AbstractSince the 1950s, Warfarin has been used globally as both a prescription drug and a rodenticide. Research has shown that warfarin and other rodenticides are present in the environment and food chain. However, emerging contaminants are subject to degradation by biotic and abiotic processes and advanced oxidation processes. In some cases, detecting the parent compound may not be possible due to the formation of structurally changed species. This approach aims to identify hydroxylated transformation products of warfarin in a laboratory setting, even after the parent compound has undergone degradation. Therefore, the Fenton reaction is utilized to insert hydroxylation into the parent compound, warfarin, by hydroxyl and hydroperoxyl radicals generated by Fe2+/Fe3+ redox reaction with hydrogen peroxide. Using multiple reaction monitoring, a GC–MS/MS method, incorporating isotopically labeled reference compounds, is used to quantify the expected derivatized species. The analytes are derivatized using trimethyl-3-trifluoromethyl phenyl ammonium hydroxide, and the derivatization yield of warfarin is determined by using isotopically labeled reference compounds. The method has a linear working range of 30 to 1800 ng/mL, with detection limits ranging from 18.7 to 67.0 ng/mL. The analytes are enriched using a C18-SPE step, and the recovery for each compound is calculated. The Fenton reaction generates all preselected hydroxylated transformation products of warfarin. The method successfully identifies that 4′-Me-O-WAR forms preferentially under the specified experimental conditions. By further optimizing the SPE clean-up procedures, this GC–MS-based method will be suitable for detecting transformation products in more complex matrices, such as environmental water samples. Overall, this study provides a better understanding of warfarin’s degradation and offers a robust analytical tool for investigating its transformation products.
KW - Health, Toxicology and Mutagenesis
KW - Pollution
KW - Environmental Chemistry
KW - General Medicine
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595737
DO - https://doi.org/10.1007/s11356-024-32133-3
SN - 0944-1344
VL - 31
SP - 16986
EP - 16994
PB - Springer Science and Business Media LLC
AN - OPUS4-59573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Distributed acoustic sensing to monitor ground motion/movement at multi-frequency bands
N2 - A novel distributed acoustic sensing technique is proposed that exploits both phase and amplitude of the Rayleigh backscattered light to quantify the environmental variation. The system employs a wavelength-scanning laser and an imbalanced Mach-Zehnder interferometer to acquire the reflection spectra and the phase of the detected light, respectively. Fading-free and low-frequency measurements are realized via the crosscorrelation of the reflection spectra. The discrete crosscorrelation is used to circumvent the nonlinear frequency sweeping of the laser. Based on the phase of the backscattered light, it is possible to quantify fast environmental variations. The whole system requires no hardware modification of the existing system and its functionality is experimentally validated. The proposed system has the potential to monitor ground motion/movement at very low frequency band like subsidence around mining areas and at high frequency band like earthquakes and vibrations induced by avalanches.
KW - Distributed acoustic sensing
KW - DAS
KW - Distributed fiber optic sensing
KW - Ground motion detection
KW - Subsidence monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596129
DO - https://doi.org/10.1109/JLT.2024.3358495
VL - 42
IS - 18
SP - 1
EP - 8
PB - Optical Society und IEEE Photonics Society
AN - OPUS4-59612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kornev, Roman
A1 - Gornushkin, Igor B.
A1 - Shabarova, Lubov
A1 - Kadomtseva, Alena
A1 - Mochalov, Georgy
A1 - Rekunov, Nikita
A1 - Romanov, Sergey
A1 - Medov, Vitaly
A1 - Belousova, Darya
A1 - Maleev, Nikita
T1 - Plasma-Chemical Disposal of Silicon and Germanium Tetrachlorides Waste by Hydrogen Reduction
N2 - The processes of hydrogen reduction of silicon and germanium chlorides under the conditions of high-frequency (40.68 MHz) counteracted arc discharge stabilized between two rod electrodes are investigated. The main gas-phase and solid products of plasma-chemical transformations are determined. Thermodynamic analysis of SiCl4 + H2 and GeCl4 + H2 systems for optimal process parameters was carried out. Using the example of hydrogen reduction of SiCl4 by the method of numerical modeling, gas-dynamic and thermal processes for this type of discharge are investigated. The impurity composition of gas-phase and solid reaction products is investigated. The possibility of single-stage production of high-purity Si and Ge mainly in the form of compact ingots, as well as high-purity chlorosilanes and trichlorogermane, is shown.
KW - High-frequency arc discharge
KW - Hydrogen reduction
KW - Silicon chlorides
KW - Germanium chlorides
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594454
DO - https://doi.org/10.3390/sci6010001
VL - 6
IS - 1
SP - 1
EP - 12
PB - MDPI AG
AN - OPUS4-59445
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Esparza Mora, Margy Alejandra
A1 - Mazumdar, Tilottama
A1 - Jiang, Shixiong
A1 - Radek, Renate
A1 - Thiem, Julian N.
A1 - Feng, Linshan
A1 - Petrašiūnaitė, Vesta
A1 - Banasiak, Ronald
A1 - Golian, Marek
A1 - Gleske, Melanie
A1 - Christophe, Lucas
A1 - Springer, Andreas
A1 - Buellesbach, Jan
A1 - McMahon, Dino Peter
T1 - Defensive behavior is linked to altered surface chemistry following infection in a termite society
N2 - The care-kill response determines whether a sick individual will be treated or eliminated from an insect society, but little is known about the physiological underpinnings of this process. We exploited the stepwise infection dynamics of an entomopathogenic fungus in a termite to explore how care-kill transitions occur, and identify the chemical cues behind these shifts. We found collective responses towards pathogen-injected individuals to vary according to severity and timing of pathogen challenge, with elimination, via cannibalism, occurring sooner in response to a severe active infection. However, injection with inactivated fungal blastospores also resulted in increased albeit delayed cannibalism, even though it did not universally cause host death. This indicates that the decision to eliminate an individual is triggered before pathogen viability or terminal disease status has been established. We then compared the surface chemistry of differently challenged individuals, finding increased amounts of long-chained methyl-branched alkanes with similar branching patterns in individuals injected with both dead and viable fungal blastospores, with the latter showing the largest increase. This coincided with the highest amounts of observed cannibalism as well as signs of severe moribundity. Our study provides new mechanistic insight into the emergent collective behaviors involved in the disease defense of a termite society.
KW - Termite
KW - Social Immunity
KW - CHC
KW - Pathogen
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594468
DO - https://doi.org/10.1038/s41598-023-42947-9
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 16
PB - Macmillan Publishers Limited, part of Springer Nature
CY - London
AN - OPUS4-59446
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grundmann, Jana
A1 - Ermilova, Elena
A1 - Hertwig, Andreas
A1 - Klapetek, Petr
A1 - Pereira, Silvania F.
A1 - Rafighdoost, Jila
A1 - Bodermann, Bernd
T1 - Optical and Tactile Measurements on SiC Sample Defects
N2 - The different defect types on SiC samples are measured with various measurement methods including optical and tactile methods. The defect types investigated include particles, carrots and triangles and they are analyzed with imaging ellipsometry, coherent Fourier scatterometry and atomic force microscopy. Each of these methods measures different properties of the defects and they all together contribute to a complete analysis.
T2 - SMSI 2023 - Sensor and Measurement Science International
CY - Nuremberg, Germany
DA - 08.05.2023
KW - Defects
KW - Silicon carbide
KW - Imaging ellipsometry
KW - Atomic force microscopy
KW - Coherent Fourier scatterometry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593397
SN - 978-3-9819376-8-8
DO - https://doi.org/10.5162/SMSI2023/D5.2
VL - 2023/D5
SP - 233
EP - 234
PB - AMA Service
CY - Wunstorf
AN - OPUS4-59339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - Birkholz, Henk
A1 - Jung, Matthias
A1 - Waitelonis, Jörg
A1 - Mädler, Lutz
A1 - Sack, Harald
T1 - PMD Core Ontology: Achieving semantic interoperability in materials science
N2 - Knowledge representation in the Materials Science and Engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant (consistent) and variant (context-specific) knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this paper, an approach how to maintain a comprehensive MSE-centric terminology composing a mid-level ontology–the Platform MaterialDigital Core Ontology (PMDco)–via MSE community-based curation procedures is presented. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics. Additionally, it demonstrates how the PMDco lowers development and integration thresholds. Moreover, the research highlights how to fuel it with real-world data sources ranging from manually conducted experiments and simulations with continuously automated industrial applications.
KW - Ontology
KW - Materials science and engineering
KW - Knowledge representation
KW - Reproducibility
KW - Semantic interoperability
KW - Semantic data integration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592948
DO - https://doi.org/10.1016/j.matdes.2023.112603
SN - 0264-1275
VL - 237
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-59294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gottinger, A.
A1 - Ladu, Luana
A1 - Blind, K.
T1 - Standardization in the context of science and regulation: An analysis of the Bioeconomy
N2 - Standards play a crucial role in the transition to more sustainable production and consumption models by promoting the development of new markets for innovative products. In the case of the bioeconomy, standards are particularly relevant to ensure the sustainability of products and processes. Hence, standards represent an essential strategic tool to foster sustainable development. Furthermore, the standard-setting process brings together different stakeholders, which encourages research and the transfer of knowledge to industrial practice. In particular, scientific publications assist the standardisation process by providing scientific evidence. This study investigates the role of science and regulation in the bioeconomy standardisation process. It first provides a general analysis of bioeconomy-related standards, followed by an analysis of the regulations and publications referenced in the standards. Our analysis discloses a strong use of scientific knowledge in the bioeconomy standardisation process and demonstrates the readiness to integrate novel academic findings into revised versions of the standards. In addition, it reveals that the interaction between science and regulation is an important driver for standardisation activities around the bioeconomy, needed to support sustainable transitions.
KW - Bioeconomy
KW - Standardisation
KW - Knowledge Use
KW - Socio-technical Transition
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599899
DO - https://doi.org/10.1016/j.envsci.2023.06.013
VL - 147
SP - 188
EP - 200
PB - Elsevier
AN - OPUS4-59989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jablonka, Kevin Maik
A1 - Ai, Qianxiang
A1 - Al-Feghali, Alexander
A1 - Badhwar, Shruti
A1 - Bocarsly, Joshua D.
A1 - Bran, Andres M.
A1 - Bringuier, Stefan
A1 - Brinson, L. Catherine
A1 - Choudhary, Kamal
A1 - Circi, Defne
A1 - Cox, Sam
A1 - de Jong, Wibe A.
A1 - Evans, Matthew L.
A1 - Gastellu, Nicolas
A1 - Genzling, Jerome
A1 - Gil, María Victoria
A1 - Gupta, Ankur K.
A1 - Hong, Zhi
A1 - Imran, Alishba
A1 - Kruschwitz, Sabine
A1 - Labarre, Anne
A1 - Lála, Jakub
A1 - Liu, Tao
A1 - Ma, Steven
A1 - Majumdar, Sauradeep
A1 - Merz, Garrett W.
A1 - Moitessier, Nicolas
A1 - Moubarak, Elias
A1 - Mouriño, Beatriz
A1 - Pelkie, Brenden
A1 - Pieler, Michael
A1 - Ramos, Mayk Caldas
A1 - Ranković, Bojana
A1 - Rodriques, Samuel G.
A1 - Sanders, Jacob N.
A1 - Schwaller, Philippe
A1 - Schwarting, Marcus
A1 - Shi, Jiale
A1 - Smit, Berend
A1 - Smith, Ben E.
A1 - Van Herck, Joren
A1 - Völker, Christoph
A1 - Ward, Logan
A1 - Warren, Sean
A1 - Weiser, Benjamin
A1 - Zhang, Sylvester
A1 - Zhang, Xiaoqi
A1 - Zia, Ghezal Ahmad Jan
A1 - Scourtas, Aristana
A1 - Schmidt, K. J.
A1 - Foster, Ian
A1 - White, Andrew D.
A1 - Blaiszik, Ben
T1 - 14 examples of how LLMs can transform materials science and chemistry: a reflection on a large language model hackathon
N2 - Large-language models (LLMs) such as GPT-4 caught the interest of many scientists. Recent studies suggested that these models could be useful in chemistry and materials science. To explore these possibilities, we organized a hackathon. This article chronicles the projects built as part of this hackathon. Participants employed LLMs for various applications, including predicting properties of molecules and materials, designing novel interfaces for tools, extracting knowledge from unstructured data, and developing new educational applications. The diverse topics and the fact that working prototypes could be generated in less than two days highlight that LLMs will profoundly impact the future of our fields. The rich collection of ideas and projects also indicates that the applications of LLMs are not limited to materials science and chemistry but offer potential benefits to a wide range of scientific disciplines.
KW - Large Language model
KW - Hackathon
KW - Concrete
KW - Prediction
KW - Inverse Design
KW - Orchestration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589961
DO - https://doi.org/10.1039/d3dd00113j
VL - 2
IS - 5
SP - 1233
EP - 1250
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moreno Torres, Benjami
A1 - Völker, Christoph
A1 - Firdous, Rafia
T1 - Concreting a sustainable future: A dataset of alkali-activated concrete and its properties
N2 - This data article introduces a dataset comprising 1630 alkali-activated concrete (AAC) mixes, compiled from 106 literature sources. The dataset underwent extensive curation to address feature redundancy, transcription errors, and duplicate data, yielding refined data ready for further data-driven science in the field of AAC, where this effort constitutes a novelty. The carbon footprint associated with each material used in the AAC mixes, as well as the corresponding CO2 footprint of every mix, were approximated using two published articles. Serving as a foundation for future expansions and rigorous data applications, this dataset enables the characterization of AAC properties through machine learning algorithms or as a benchmark for performance comparison among different formulations. In summary, the dataset provides a resource for researchers focusing on AAC and related materials and offers insights into the environmental benefits of substituting traditional Portland concrete with AAC.
KW - Multidisciplinary
KW - Data Set
KW - Alkali Activated Concrete
KW - Data driven design
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589974
DO - https://doi.org/10.1016/j.dib.2023.109525
SN - 2352-3409
VL - 50
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-58997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
A1 - Zia, Ghezal Ahmad Jan
A1 - Rug, Tehseen
A1 - Firdous, Rafia
A1 - Böhmer, Felix
A1 - Stephan, Dietmar
A1 - Kruschwitz, Sabine
T1 - Presenting SLAMD – A Sequential Learning Based Software for the Inverse Design of Sustainable Cementitious Materials
N2 - In recent decades, the number of components in concrete has grown, particularly in formulations aimed at reducing carbon footprints. Innovations include diverse binders, supplementary cementitious materials, activators, concrete admixtures, and recycled aggregates. These developments target not only the enhancement of material properties but also the mitigation of the ecological and economic impacts of concrete — the most extensively used material by humankind. However, these advancements also introduce a greater variability in the composition of raw materials. The material’s behavior is significantly influenced by its nanoscale properties, which can pose challenges in accurate characterization. Consequently, there’s an increasing need for experimental tuning of formulations. This is accompanied by a more inconsistent composition of raw materials, which makes an experimental tuning of formulations more and more necessary. However, the increased complexity in composition presents a challenge in finding the ideal formulation through trial and error. Inverse design (ID) techniques offer a solution to this challenge by allowing for a comprehensive search of the entire design space to create new and improved concrete formulations. In this publication, we introduce the concept of ID and demonstrate how our open-source app “SLAMD” provides all necessary steps of the workflow to adapt it in the laboratory, lowering the application barriers. The intelligent screening process, guided by a predictive model, leads to a more efficient and effective data-driven material design process resulting in reduced carbon footprint and improved material quality while considering socio-economic factors in the materials design.
KW - Sustainable concrete
KW - Machine learning optimization
KW - Inverse design techniques
KW - Scientific software
KW - Data-driven material design
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589993
DO - https://doi.org/10.17756/nwj.2023-s2-032
VL - 9
SP - 180
EP - 187
AN - OPUS4-58999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gehrenkemper, Lennart
A1 - Rühl, Isabel
A1 - Westphalen, Tanja
A1 - Simon, Fabian
A1 - von der Au, Marcus
A1 - Cossmer, Antje
A1 - Meermann, Björn
T1 - Investigating the uptake and fate of per- and polyfluoroalkylated substances (PFAS) in bean plants (Phaseolus vulgaris): comparison between target MS and sum parameter analysis via HR-CS-GFMAS
N2 - AbstractIn this study, we present a screening method based on molecular absorption spectrometry to study PFAS uptake and fate in plants. To evaluate the suitability of this method we analyzed plant extracts with molecular absorption spectrometry (MAS) as well as liquid chromatography–tandem mass spectrometry (LC–MS/MS) for mass balance studies (w(F)). French bean plants (Phaseolus vulgaris) were grown on soil spiked using eight PFAS substances that vary in chain length and functional group composition. Specifically, these include three short-chained (C4–C5), five long-chained (C7–C10) carboxylic acids, one sulfonic acid and one sulfonic amide moieties. To investigate substance-specific PFAS uptake systematically, PFAS were spiked as single substance spike. Additionally, we studied one mixture of the investigated substances in equal proportions regarding w(F) and four PFAS mixtures of unknown composition. After 6 weeks, the plants were separated into four compartments. We analyzed the four compartments as well as the soil for extractable organically bound fluorine (EOF) by high resolution-continuum source-graphite furnace-molecular absorption spectrometry (HR-CS-GFMAS) as well as for sum of ten target-PFAS by LC–MS/MS. All three short-chained PFAS perfluorobutanoic acid (PFBA), perfluorobutanoic sulfonic acid (PFBS) and perfluoropentanoic acid (PFPeA) were determined in high concentrations mainly in the fruits of the investigated plants while long-chained PFAS perfluorononanoic acid (PFNA) and perfluorodecanoic acid (PFDA) were mainly determined in roots. PFBS was determined in remarkably high concentrations in leaves compartment by both quantification methods. Overall, comprehensive results of single substance spikes were in good agreement for both methods except for a few cases. Hence, two phenomena were identified: for mixed PFAS spikes of unknown composition huge differences between EOF and sum of target PFAS were observed with systematically higher EOF values. Overall, both methods indicate comparable results with MS being more reliable for known PFAS contamination and MAS being more valuable to identify PFAS exposure of unknown composition.
Graphical Abstract
KW - Pollution
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589394
DO - https://doi.org/10.1186/s12302-023-00811-7
VL - 35
IS - 104
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-58939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rieger, Philip
A1 - Magnall, Joseph M.
A1 - Gleeson, Sarah A.
A1 - Oelze, Marcus
T1 - Pyrite chemistry records a multistage ore forming system at the Proterozoic George Fisher massive sulfide Zn-Pb-Ag deposit, Mount Isa, Australia
N2 - Trace element (TE) analysis of pyrite via LA-ICP-MS can be used to reconstruct the conditions of pyrite formation in complex mineral systems. The Carpentaria province in northern Australia is host to some of the world’s highest value Zn-Pb (+Ag, Cu) deposits. The genesis of many of these deposits is controversial, with competing models of single-vs. multi-stage ore formation. In this study, LA-ICP-MS data of paragenetically constrained pyrite from the George Fisher Zn-Pb-Ag deposit has been analysed to investigate the chemistry of different stages of ore formation. Pyrite from correlative unmineralized host rocks has also been analysed to investigate evidence of distal hydrothermal anomalism. All LA-ICP-MS data have been statistically evaluated (principal component analysis) and interpreted together with whole rock lithogeochemical data of the same samples. Pre-ore diagenetic pyrite is compositionally similar to other Proterozoic diagenetic pyrite, with some evidence of minor hydrothermal anomalism that with further analysis could help define distal alteration. Pyrite from the different ore stages are compositionally distinct, consistent with a multi-stage system. Ore stage 1 pyrite exceeds background contents of Co, Cu, Zn, As, Ag, Sb, Tl, and Pb and has elevated Co/Ni ratios, whereas only Ni and Co are above background abundances in ore stage 2 and 3 pyrite, of which only ore stage 3 pyrite has high Co/Ni ratios. Ore stage 1 pyrite has a similar composition to hydrothermal pyrite in the undeformed northern Carpentaria CD-type deposits and was likely syn-diagenesis. Ore stage 2 was syn-deformation, and resulted in replacement and recrystallization of pre-existing pyrite, and the expulsion of incompatible TEs. Ore stage 3 formed via a later Cu-Zn-Pb mineralizing event that resulted in a new geochemically distinct generation of Co-rich pyrite. Overall, this study demonstrates the value of paragenetically-constrained pyrite TE data for refining genetic models in complex sediment hosted mineral systems.
KW - General Earth and Planetary Sciences
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590407
DO - https://doi.org/10.3389/feart.2023.892759
VL - 11
SP - 1
EP - 19
PB - Frontiers Media SA
AN - OPUS4-59040
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Inostroza, Manuel
A1 - Fernandez, Bárbara
A1 - Aguilera, Felipe
A1 - Layana, Susana
A1 - Walter, Thomas R.
A1 - Zimmer, Martin
A1 - Rodríguez-Díaz, Augusto
A1 - Oelze, Marcus
T1 - Physical and chemical characteristics of active sulfur flows observed at Lastarria volcano (northern Chile) in January 2019
N2 - Molten sulfur is found in various subaerial volcanoes. However, limited records of the pools and flows of molten sulfur have been reported: therefore, questions remain regarding the physicochemical processes behind this phenomenon. A suite of new sulfur flows, some of which active, was identified at the Lastarria volcano (northern Chile) and studied using satellite imagery, in situ probing, and temperature and video recording. This finding provides a unique opportunity to better understand the emplacement mechanisms and mineral and chemical compositions of molten sulfur, in addition to gaining insight into its origin. Molten sulfur presented temperatures of 124–158°C, with the most prolonged sulfur flow reaching 12 m from the source. Photogrammetric tools permitted the identification of levees and channel structures, with an estimated average flow speed of 0.069 m/s. Field measurements yielded a total volume of 1.45 ± 0.29 m3 of sulfur (equivalent to ∼2.07 tons) mobilized during the January 2019 event for at least 408 min. Solidified sulfur was composed of native sulfur with minor galena and arsenic- and iodine-bearing minerals. Trace element analysis indicated substantial enrichment of Bi, Sb, Sn, Cd, as well as a very high concentration of As (>40.000 ppm). The January 2019 molten sulfur manifestations in Lastarria appear to be more enriched in As compared to the worldwide known volcanoes with molten sulfur records, such as the Shiretoko-Iozan and Poás volcanoes. Furthermore, their rheological properties suggest that the “time of activity” in events such as this could be underestimated as flows in Lastarria have moved significantly slower than previously thought. The origin of molten sulfur is ascribed to the favorable S-rich chemistry of fumarolic gases and changes in host rock permeability (fracture opening). Molten sulfur in Lastarria correlates with a peak in activity characterized by high emissions of SO2 and other acid species, such as HF and HCl, in addition to ground deformation. Consequently, molten sulfur was framed within a period of volcanic unrest in Lastarria, triggered by changes in the magmatic-hydrothermal system. The appearance of molten sulfur is related to physicochemical perturbations inside the volcanic system and is perhaps a precursor of eruptive activity, as observed in the Poás and Turrialba volcanoes.
KW - General Earth and Planetary Sciences
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590331
DO - https://doi.org/10.3389/feart.2023.1197363
VL - 11
SP - 1
EP - 18
PB - Frontiers Media SA
AN - OPUS4-59033
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klewe, Tim
A1 - Völker, Tobias
A1 - Landmann, Mirko
A1 - Kruschwitz, Sabine
T1 - LIBS‐ConSort: Development of a sensor‐based sorting method for construction and demolition waste
N2 - AbstractA joint project of partners from industry and research institutions approaches the challenge of construction and demolition waste (CDW) sorting by investigating and testing the combination of laser‐induced breakdown spectroscopy (LIBS) with near‐infrared (NIR) spectroscopy and visual imaging. Joint processing of information (data fusion) is expected to significantly improve the sorting quality of various materials like concrete, main masonry building materials, organic components, etc., and may enable the detection and separation of impurities such as SO3‐cotaining building materials (gypsum, aerated concrete, etc.)Focusing on Berlin as an example, the entire value chain will be analyzed to minimize economic / technological barriers and obstacles at the cluster level and to sustainably increase recovery and recycling rates.The objective of this paper is to present current progress and results of the test stand development combining LIBS with NIR spectroscopy and visual imaging. In the future, this laboratory prototype will serve as a fully automated measurement setup to allow real‐time classification of CDW on a conveyor belt.
T2 - 21st Ibausil - International Conference on Building Materials
CY - Weimar, Germany
DA - 13.09.2023
KW - NDT
KW - Material cassification
KW - Recycling
KW - LIBS
KW - Data fusion
KW - Construction and demolition waste
KW - Circular economy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590734
DO - https://doi.org/10.1002/cepa.2866
SN - 2509-7075
VL - 6
IS - 6
SP - 973
EP - 976
PB - Ernst & Sohn GmbH
AN - OPUS4-59073
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charmi, Amir
A1 - Mustapha, Samir
A1 - Yilmaz, Bengisu
A1 - Heimann, Jan
A1 - Prager, Jens
T1 - A Machine Learning Based-Guided Wave Approach for Damage Detection and Assessment in Composite Overwrapped Pressure Vessels
N2 - The applications of composite overwrapped pressure vessels (COPVs) in extreme conditions, such as storing hydrogen gases at very high pressure, impose new requirements related to the system's integrity and safety. The development of a structural health monitoring (SHM) system that allows for continuous monitoring of the COPVs provides rich information about the structural integrity of the component. Furthermore, the collected data can be used for different purposes such as increasing the periodic inspection intervals, providing a remaining lifetime prognosis, and also ensuring optimal operating conditions. Ultimately this information can be complementary to the development of the envisioned digital twin of the monitored COPVs. Guided waves (GWs) are preferred to be used in continuous SHM given their ability to travel in complex structures for long distances. However, obtained GW signals are complex and require advanced processing techniques. Machine learning (ML) is increasingly utilized as the main part of the processing pipeline to automatically detect anomalies in the system's integrity. Hence, in this study, we are scrutinizing the potential of using ML to provide continuous monitoring of COPVs based on ultrasonic GW data. Data is collected from a network of sensors consisting of fifteen Piezoelectric (PZT) wafers that were surface mounted on the COPV. Two ML algorithms are used in the automated evaluation procedure (i) a long short-term memory (LSTM) autoencoder for anomaly detection (defects/impact), and (ii) a convolutional neural network (CNN) model for feature extraction and classification of the artificial damage sizes and locations. Additional data augmentation steps are introduced such as modification and addition of random noise to original signals to enhance the model's robustness to uncertainties. Overall, it was shown that the ML algorithms used were able to detect and classify the simulated damage with high accuracy.
T2 - 13th European Conference on Non-Destructive Testing (ECNDT) 2023
CY - Lisbon, Portugal
DA - 03.07.2023
KW - Machine learning
KW - Structural health monitoring
KW - COPV
KW - Guided waves
KW - Damage localization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590789
DO - https://doi.org/10.58286/28079
SN - 2941-4989
VL - 1
IS - 1
SP - 1
EP - 6
PB - NDT.net
CY - Mayen
AN - OPUS4-59078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mustapha, S.
A1 - Yilmaz, Bengisu
A1 - Heimann, Jan
A1 - Brence, Blaz
A1 - Prager, Jens
T1 - Guided Waves Propagation in Composite Overwrapped Pressure Vessel
N2 - The application of composite overwrapped pressure vessels (COPV) to store hydrogen and other compressed gases, especially when operating at high pressures, imposed the need for an innovative and reliable approach to ensure the safe operation of the system. Continuous structural health monitoring (SHM) based on ultrasonic guided waves (GWs) is a promising approach due to the ability of the wave to propagate for long distances and go around complex structures, moreover the high sensitivity to various failure modes such as delamination, matrix cracking and debonding. In this study, we scrutinize the behavior of (GWs) within the COPV using a network of PZT elements that are used for excitation and sensing. A laser doppler vibrometer (LDV) was also used to scan the surface of the vessel in various directions. L(0,1) and L(0,2) were observed in the captured signal. The L(0, 2) appeared to be a dominant mode in the COPV and was capable of propagating along the entire length and maintaining a good signal-to-noise ratio. The L(0,2) mode maintained the same phase velocity when it is captured at various excitation angles (0, 45, and 90 degrees). The reduced effect of the orthotropy of the materials on the propagating waves is an important result as it will reduce the complexity in data processing when performing damage identification.
T2 - 13th. European Conference on Non-Destructive Testing (ECNDT)
CY - Lisbon, Portugal
DA - 03.07.2023
KW - Composite Overwrapped Pressure Vessels
KW - Guided Waves
KW - Laser Doppler Vibrometer
KW - Structural Health Monitoring
KW - Sensors Placement
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591081
DO - https://doi.org/10.58286/28068
SN - 2941-4989
VL - 1
IS - 1
SP - 1
EP - 6
PB - NDT.net
CY - Mayen
AN - OPUS4-59108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yilmaz, Bengisu
A1 - Heimann, Jan
A1 - Mustapha, S.
A1 - Charmi, Amir
A1 - Prager, Jens
T1 - Guided wave ultrasonic feature determination in Type IV composite overwrapped pressure vessels towards the digital twin
N2 - The digitalization of quality control processes and the underlying data infrastructures for safety relevant components, such as hydrogen pressure vessels, plays a significant role in the transition towards Industry 4.0. In the current safety regulations for hydrogen pressure vessels, there is no established concept for structural health monitoring. The development of a reliable structural health monitoring methodology for monitoring the structural integrity of pressure vessels enables a fast-forward transition from personnel- and costintensive recurring inspections, a.k.a. periodic maintenance, to predictive maintenance. In the work presented; we investigated the application of ultrasonic guided wave propagation to monitor and assess the condition of Type IV composite overwrapped pressure vessel (COPV). A sensor network of fifteen piezo-electric wafers is placed on the carbon fibre reinforced composite cylinder. Five different artificial damage configurations are created by gluing two different weight blocks on three different locations. The database containing measured guided wave data sets is enriched by two different boundary conditions. We utilized an open-source software, openBIS labnotebook, to store and analyse experimental datasets. The guided wave ultrasonic signals were investigated and analysed by using commonly used ultrasonic features (e.g., amplitude, frequency, time of flight) as well as non-traditional time-series features (kurtosis, skewness, variance). The features were used to calculate damage index and the detection performance for the results has been evaluated. The results suggest that both traditional and non-traditional features assume significant importance in artificial damage detection. The future works will additionally involve the impacts of operational conditions, such as periodic pressure variations temperature loadings as well as material degradations.
T2 - 13th European Conference on Non-Destructive Testing (ECNDT)
CY - Lisbon, Portugal
DA - 03.07.2023
KW - Industry 4.0
KW - Composite overwrapped pressure vessels
KW - Structural health monitoring
KW - Ultrasonic guided waves
KW - Predictive maintenance
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591094
DO - https://doi.org/10.58286/28072
SN - 2941-4989
VL - 1
IS - 1
SP - 1
EP - 6
PB - NDT.net
CY - Mayen
AN - OPUS4-59109
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ruyle, B.
A1 - Pickard, H.
A1 - Schultes, L.
A1 - Fredriksson, F.
A1 - Heffernan, A.
A1 - Knappe, D.
A1 - Lord, H.
A1 - Meng, P.
A1 - Mills, M.
A1 - Ndungu, K.
A1 - Roesch, Philipp
A1 - Rundberget, J.T.
A1 - Tettenhorst, D.
A1 - Van Buren, J.
A1 - Vogel, Christian
A1 - Westerman, D.
A1 - Yeung, L.
A1 - Sunderland, E.
T1 - Interlaboratory Comparison of Extractable Organofluorine Measurements in Groundwater and Eel (Anguilla rostrata): Recommendations for Methods Standardization
N2 - Research on per- and polyfluoroalkyl substances (PFAS) frequently incorporates organofluorine measurements, particularly because they could support a class-based approach to regulation. However, standardized methods for organofluorine analysis in a broad suite of matrices are currently unavailable, including a method for extractable organofluorine (EOF) measured using combustion ion chromatography (CIC). Here, we report the results of an international interlaboratory comparison. Seven laboratories representing academia, government, and the private sector measured paired EOF and PFAS concentrations in groundwater and eel (Anguilla rostrata) from a site contaminated by aqueous film-forming foam. Among all laboratories, targeted PFAS could not explain all EOF in groundwater but accounted for most EOF in eel. EOF results from all laboratories for at least one replicate extract fell within one standard deviation of the interlaboratory mean for groundwater and five out of seven laboratories for eel. PFAS spike mixture recoveries for EOF measurements in groundwater and eel were close to the criterion (±30%) for standardized targeted PFAS methods. Instrumental operation of the CIC such as replicate sample injections was a major source of measurement uncertainty. Blank contamination and incomplete inorganic fluorine removal may introduce additional uncertainties. To elucidate the presence of unknown organofluorine using paired EOF and PFAS measurements, we recommend that analysts carefully consider confounding methodological uncertainties such as differences in precision between measurements, data processing steps such as blank subtraction and replicate analyses, and the relative recoveries of PFAS and other fluorine compounds.
KW - Extractable organic fluorine
KW - Per- and Polyfluoroalkyl substances (PFAS)
KW - Combustion ion chromatography (CIC)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587726
DO - https://doi.org/10.1021/acs.est.3c04560
SN - 0013-936X
VL - 57
IS - 48
SP - 20159
EP - 20168
PB - American Chemical Society (ACS)
AN - OPUS4-58772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmier, Michael
T1 - Influence of the spatial laser energy absorption on the molten pool dynamics in high-power laser beam welding
N2 - The spatial laser energy absorption inside the keyhole is decisive for the dynamic molten pool behaviors and the resultant weld properties in high-power laser beam welding (LBW). In this paper, a numerical simulation of the LBW process, considering the 3D transient heat transfer, fluid flow, and keyhole dynamics, is implemented, in which the free surface is tracked by the volume-of-fluid algorithm. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by an advanced ray-tracing method based on a localized level-set strategy and a temperature-dependent absorption coefficient. The laser energy absorption is analyzed from a time-averaged point of view for a better statistical representation. It is found for the first time that a significant drop in the time-averaged laser energy absorption occurs at the focus position of the laser beam and that the rest of the keyhole region has relatively homogeneous absorbed energy. This unique absorption pattern may lead to a certain keyhole instability and have a strong correlation with the detrimental bulging and narrowing phenomena in the molten pool. The influence of different focus positions of the laser beam on the keyhole dynamics and molten pool profile is also analyzed. The obtained numerical results are compared with experimental measurements to ensure the validity of the proposed model.
KW - Laser beam welding
KW - Laser energy absorption
KW - Molten pool
KW - Keyhole dynamics
KW - Numerical modeling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587531
DO - https://doi.org/10.2351/7.0001078
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 8
PB - AIP Publishing
AN - OPUS4-58753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudhuri, Somsubhro
A1 - Stamm, Michael
A1 - Krankenhagen, Rainer
T1 - Weather-dependent passive thermography and thermal simulation of in-service wind turbine blades
N2 - . To cope with the increase in the manufacturing and operation of wind turbines, wind farm operators need inspection tools that are able to provide reliable information while keeping the downtime low. Current inspection techniques require to stop the wind turbine. This work presents the current progress in the project EvalTherm, in which passive thermography is evaluated as a possible non-destructive inspection tool for operational wind turbine blades (WTBs). A methodology to obtain thermal images of rotating WTBs has been established in this project. However, the quality of the results is heavily dependent on various aspects such as weather conditions, information on the inspected WTB, damage history, etc. In this work, a section of a used WTB is simulated using finite-element modelling (FEM) as well as experimentally tested for evaluating the accuracy of the model. Such a model will provide insight into the potential thermal response of a certain structure (with specific material properties) in given weather (boundary) conditions. The model is able to provide satisfactory predictions of the thermal response of the structure, as well as indicate what thermal contrast(s) result from artificial defects introduced in the structure.
T2 - WindEurope Annual Event 2023
CY - Copenhagen, Denmark
DA - 25.04.2023
KW - FEM
KW - Thermografie
KW - Wind turbine rotor blades
KW - Windenergie Anlage Rotorblätter
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582777
DO - https://doi.org/10.1088/1742-6596/2507/1/012025
VL - 2507
SP - 1
EP - 12
PB - IOP Publishing Ltd.
AN - OPUS4-58277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Moreno Torres, Benjami
A1 - Rug, Tehseen
A1 - Firdous, Rafia
A1 - Zia, Ghezal Ahmad Jan
A1 - Lüders, Stefan
A1 - Lisdero Scaffino, Horacio
A1 - Höpler, Michael
A1 - Böhmer, Felix
A1 - Pfaff, Matthias
A1 - Stephan, Dietmar
A1 - Kruschwitz, Sabine
T1 - Data driven design of alkali-activated concrete using sequential learning
N2 - This paper presents a novel approach for developing sustainable building materials through Sequential Learning. Data sets with a total of 1367 formulations of different types of alkali-activated building materials, including fly ash and blast furnace slag-based concrete and their respective compressive strength and CO2-footprint, were compiled from the literature to develop and evaluate this approach. Utilizing this data, a comprehensive computational study was undertaken to evaluate the efficacy of the proposed material design methodologies, simulating laboratory conditions reflective of real-world scenarios. The results indicate a significant reduction in development time and lower research costs enabled through predictions with machine learning. This work challenges common practices in data-driven materials development for building materials. Our results show, training data required for data-driven design may be much less than commonly suggested. Further, it is more important to establish a practical design framework than to choose more accurate models. This approach can be immediately implemented into practical applications and can be translated into significant advances in sustainable building materials development.
KW - Sustainable building materials
KW - Sequential learning
KW - Data-driven materials design
KW - Alkali-activated building materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584376
UR - https://www.sciencedirect.com/science/article/pii/S095965262302379X
DO - https://doi.org/10.1016/j.jclepro.2023.138221
SN - 0959-6526
SN - 1879-1786
VL - 418
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-58437
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Tabasco-Novelo, Carolina
A1 - Quintana, Patricia
A1 - Rodriguez-Gattorno, Geonel
A1 - Alvarado-Gil, Juan J.
T1 - Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions
N2 - In this work, the thermal properties of ternary Li₃ₓCo₇₋₄ₓSb₂₊ₓO₁₂ solid solutions are studied for different concentrations in the range 0 ≤ x ≤ 0.7. Samples are elaborated at four different sintering temperatures: 1100, 1150, 1200 and 1250 °C. The effect of increasing the content of Li⁺ and Sb⁵⁺, accompanied by the reduction of Co²⁺, on the thermal properties is studied. It is shown that a thermal diffusivity gap, which is more pronounced for low values of x, can be triggered at a certain threshold sintering temperature (around 1150 °C in this study). This effect is explained by the increase of contact area between adjacent grains. Nevertheless, this effect is found to be less pronounced in the thermal conductivity. Moreover, a new framework for heat diffusion in solids is presented that establishes that both the heat flux and the thermal energy (or heat) satisfy a diffusion equation and therefore highlights the importance of thermal diffusivity in transient heat conduction phenomena.
KW - General Chemical Engineering
KW - General Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593248
DO - https://doi.org/10.1021/acsomega.2c07557
SN - 2470-1343
VL - 8
IS - 8
SP - 7808
EP - 7815
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-59324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bente, Klaas
A1 - Rus, J.
A1 - Mooshofer, H.
A1 - Gaal, Mate
A1 - Grosse, C.U.
T1 - Broadband air-coupled ultrasound emitter and receiver enable simultaneous measurement of thickness and speed of sound in solids
N2 - Air-coupled ultrasound sensors have advantages over contact ultrasound sensors when a sample should not become contaminated or influenced by the couplant or the measurement has to be a fast and automated inline process. Thereby, air-coupled transducers must emit high-energy pulses due to the low air-to-solid power transmission ratios (10−3 to 10−8). Currently used resonant transducers trade bandwidth—a prerequisite for material parameter analysis—against pulse energy. Here we show that a combination of a non-resonant ultrasound emitter and a non-resonant detector enables the generation and detection of pulses that are both high in amplitude (130 dB) and bandwidth (2 µs pulse width). We further show an initial application: the detection of reflections inside of a carbon fiber reinforced plastic plate with thicknesses between 1.7 mm and 10 mm. As the sensors work contact-free, the time of flight and the period of the in-plate reflections are independent parameters. Hence, a variation of ultrasound velocity is distinguishable from a variation of plate thickness and both properties are determined simultaneously. The sensor combination is likely to find numerous industrial applications necessitating high automation capacity and opens possibilities for air-coupled, single-side ultrasonic inspection.
KW - Thermoacoustic emitter
KW - Optical microphone
KW - Air-coupled ultrasound
KW - Local resonance
KW - Thickness measurement
KW - Thickness resonance
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569533
DO - https://doi.org/10.3390/s23031379
VL - 23
IS - 3
SP - 1379
PB - MDPI
AN - OPUS4-56953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ghafafian, Carineh
A1 - Trappe, Volker
ED - Vassilopoulos, A. P.
ED - Michaud, V.
T1 - Fully-reversed fatigue behavior of scarf joint repairs for wind turbine blade shell applications
N2 - To enable a quick and cost-effective return to service for wind turbine blades, localized repairs can be executed by technicians in the field. Scarf repairs, shown to be highly efficient with a smooth load transition across angled joint walls and a restored aerodynamic profile, are the focus of this work. The failure mechanisms of these structures were examined under quasi-static tensile and fully-reversed cyclic loading. While the scarf ratio was held constant at 1:50, the repair layup was varied between large-to-small and small-to-large. The effect of the presence of resin pockets and the fiber orientation mismatch between parent and repair material on the restored strength of BIAX ±45° glass fiber reinforced polymer scarf joint structures was studied.
T2 - 20th European Conference on Composite Materials
CY - Lausanne, Switzerland
DA - 26.06.2022
KW - Fatigue
KW - Scarf repairs
KW - Glass fiber reinforced polymers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569646
UR - https://infoscience.epfl.ch/record/298799
SN - 978-2-9701614-0-0
VL - Vol. 5 - Applications and structures
SP - 195
EP - 201
PB - Composite Construction Laboratory (CCLab)
CY - Lausanne
AN - OPUS4-56964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Tobias
A1 - Gornushkin, Igor B.
T1 - Investigation of a method for the correction of self-absorption by Planck function in laser induced breakdown spectroscopy
N2 - The electron density and temperature of a laser-induced plasma can be determined from the width and intensity of the spectral lines, provided that the corresponding optical transitions are optically thin. However, the lines in laser induced plasma are often self-absorbed. One of the methods of correction of this effect is based on the use of the Planck function and an iterative numerical calculation of the plasma temperature. In this study, the method is further explored and its inherent errors and limitations are evaluated. For this, synthetic spectra are used that fully correspond to the assumed conditions of a homogeneous isothermal plasma at local thermodynamic equilibrium. Based on the error analysis, the advantages and disadvantages of the method are discussed in comparison with other methods of self-absorption correction.
KW - LIBS
KW - Self-absorption
KW - Planck function
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572677
DO - https://doi.org/10.1039/D2JA00352J
SN - 0267-9477
SP - 1
EP - 6
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-57267
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cysne Barbosa, Ana Paula
A1 - Azevedo do Nascimento, Allana
A1 - Pavasarytė, Lina
A1 - Trappe, Volker
A1 - Melo, D.
T1 - Effect of addition of thermoplastic self-healing agent on fracture toughness of epoxy
N2 - Self-healing agents have the potential to restore mechanical properties and extend service life of composite materials. Thermoplastic healing agents have been extensively investigated for this purpose in epoxy matrix composites due to their strong adhesion to epoxy and their ability to fill in microcracks. One of the most
investigated thermoplastic additives for this purpose is poly(ethylene-co-methacrylic acid) (EMAA). Despite the ability of thermoplastic healing agents to restore mechanical properties, it is important to assess how the addition of thermoplastic healing agents affect properties of the original epoxy material. In this work, EMAA was added to epoxy resin and the effect of the additive on fracture toughness of epoxy was evaluated. Results indicate that although added in low concentrations, EMAA can affect fracture toughness.
T2 - 6th Brazilian Conference on Composite Materials
CY - Tiradentes, Minas Gerais, Brazil
DA - 14.08.2022
KW - Epoxy
KW - Self-healing
KW - Thermoplastic
KW - Fracture
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572707
SN - 978-65-00-49386-3
DO - https://doi.org/10.29327/566492
SN - 2316-1337
SP - 219
EP - 222
AN - OPUS4-57270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matamoros-Veloza, A.
A1 - Stawski, Tomasz
A1 - Vargas, S.
A1 - Neville, A.
T1 - Study of a Local Structure at the Interface between Corrosion Films and Carbon Steel Surface in Undersaturated CO2 Environments
N2 - Industries transporting CO2 gas-saturated fluids have infrastructures made of carbon steel. This is a good material with great mechanical properties but prone to corrosion and potential failure. Corrosion in sweet environments involves the formation of FeCO3 as a corrosion film, which is recognized to play a protective role under certain conditions. This work on the dissolution of corrosion films in sweet environments, under acidic and undersaturated conditions, demonstrates that the effects on the integrity of steel are far more significant than the damage observed on the surface of the corrosion film. Our results prove that dissolution of FeCO3 involved the presence of an amorphous phase, the intermediate formation of FeCl2 or FeCl+, and the presence of a phase with short distance atom–atom correlations. The amorphous phase was identified as a mixture of retained γ-Fe and Fe3C. Partially broken α-Fe and Fe3C structures were identified to prove the damage on the material, confirming the interface zone without evident damage on the corrosion film. Dissolution affected both the α-Fe and FeCO3, with the lattice [102̅] from the FeCO3 crystalline structure being the fastest to dissolve. The damage of steel at the molecular scale was evident at the macroscale with pit depths of up to 250 μm. The impact on the integrity of steel can be, therefore, more drastic than frequently reported in industrial operations of CO2 transport industries that use cleaning procedures (e.g., acid treatment, pigging) as part of their operational activities.
KW - Steel
KW - Corrosion
KW - Siderite
KW - Diffraction
KW - Pair distribution function
KW - Synchrotron
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572156
DO - https://doi.org/10.1021/acsomega.2c07631
SN - 2470-1343
VL - 8
IS - 9
SP - 8497
EP - 8504
PB - ACS
AN - OPUS4-57215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Sachs, Patrick
ED - Vassilopoulos, A. P.
ED - Michaud, V.
T1 - Dynamic mechanical analysis of epoxy-matrix cross linking measured in-situ using an elastomer container
N2 - A new patented dynamic mechanical analysis (DMA) is presented, where the tensile, bending- or torsional stiffness of a media can be characterized in-situ during the phase transition from liquid to solid. An epoxy system, e.g. Hexion L285/H287, is filled into an elastomer container, such as a silicone tube. This can be mounted into a conventional OMA and, based on a linear viscoelastic approach, the storage modulus (E';G'), the loss modulus (E'';G'') and the loss angle tan(δ) can be measured at constant temperature as a function of time in order to investigate the liquid to sol-gel to solid transition. With this new method, the stiffness increase as a result of the cure process can be directly measured more precisely than with a rheometer in a shear plate set-up, because using an elastomer container gives a defined cross section for calculating the Young's modulus.
T2 - 20th European Conference on Composite Materials
CY - Lausanne, Switzerland
DA - 26.06.2022
KW - Cross linking
KW - Dynamic mechanical analysis (DMA)
KW - Thermoset polymers
KW - Cure process
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569651
UR - https://infoscience.epfl.ch/record/298799
SN - 978-2-9701614-0-0
VL - Vol. 5 - Applications and structures
SP - 181
EP - 186
PB - Composite Construction Laboratory (CCLab)
CY - Lausanne
AN - OPUS4-56965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Azevedo do Nascimento, A.
A1 - Trappe, Volker
A1 - Diniz Melo, J. D.
A1 - Cysne Barbosa, A. P.
T1 - Fatigue behavior of self-healing glass fiber/epoxy composites with addition of poly (ethylene-co-methacrylic acid) (EMAA)
N2 - The interest in repair technologies for polymer composites has increased significantly over the last decades, due to the growing use of these materials in structural applications. In this study, poly (ethylene-co-methacrylic acid) (EMAA) was used as self-healing agent to glass fiber/epoxy composite. Materials with EMAA contents of 2 wt% and 5 wt% were manufactured using Resin Transfer Molding (RTM) and the effects of the healing agent on the properties were investigated using tensile tests and Dynamic Mechanical Analysis (DMA). Results show slight variation of properties, which was more pronounced as the content of EMAA increased. In addition, the healing efficiency was investigated through fatigue tests and the addition of higher content of EMAA increased the number of cycles to failure after the healing activation cycle.
KW - Fatigue
KW - Glass fiber-epoxy composites
KW - Self-healing
KW - Smart materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569661
DO - https://doi.org/10.1016/j.polymertesting.2022.107863
SN - 0142-9418
VL - 117
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-56966
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lunkenheimer, P.
A1 - Loidl, A.
A1 - Riechers, Birte
A1 - Zaccone, A.
A1 - Samwer, K.
T1 - Thermal expansion and the glass transition
N2 - Melting is well understood in terms of the Lindemann criterion, which
essentially states that crystalline materials melt when the thermal vibrationsof their atoms become so vigorous that they shake themselves free of the binding forces. This picture does not necessarily have to hold for glasses, where the nature of the solid–liquid cross-over is highly debated. The Lindemann criterion implies that the thermal expansion coefficients of crystals are inversely proportional to their melting temperatures. Here we find that, in contrast, the thermal expansion coefficient of glasses decreases more strongly with increasing glass temperature, which marks the liquid–solid cross-over in this material class. However, this proportionality returns when the thermal expansion coefficient is scaled by the fragility, a measure of particle cooperativity. Therefore, for a glass to become liquid, it is not sufficient to simply overcome the interparticle binding energies.
Instead, more energy must be invested to break up the typical cooperative particle network that is common to glassy materials. The thermal expansion coefficient of the liquid phase reveals similar anomalous behaviour and is universally enhanced by a constant factor of approximately 3. These universalities allow the estimation of glass temperatures from thermal expansion and vice versa.
KW - Glass transition
KW - Lindemann criterion
KW - Thermal expansion
KW - Glass
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570267
DO - https://doi.org/10.1038/s41567-022-01920-5
SN - 1745-2473
SP - 1
EP - 7
PB - Nature Publishing Group
CY - London
AN - OPUS4-57026
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Rupprecht, C.
A1 - Ziegler, Mathias
T1 - Nondestructive thermographic detection of internal defects using pixel-pattern based laser excitation and photothermal super resolution reconstruction
N2 - In this work, we present a novel approach to photothermal super resolution based thermographic resolution of internal defects using two-dimensional pixel pattern-based active photothermal laser heating in conjunction with subsequent numerical reconstruction to achieve a high-resolution reconstruction of internal defect structures. With the proposed adoption of pixelated patterns generated using laser coupled high-power DLP projector technology the complexity for achieving true two-dimensional super resolution can be dramatically reduced taking a crucial step forward towards widespread practical viability. Furthermore, based on the latest developments in high-power DLP projectors, we present their first application for structured pulsed thermographic inspection of macroscopic metal samples. In addition, a forward solution to the underlying inverse problem is proposed along with an appropriate heuristic to find the regularization parameters necessary for the numerical inversion in a laboratory setting. This allows the generation of synthetic measurement data, opening the door for the application of machine learning based methods for future improvements towards full automation of the method. Finally, the proposed method is experimentally validated and shown to outperform several established conventional thermographic testing techniques while conservatively improving the required measurement times by a factor of 8 compared to currently available photothermal super resolution techniques.
KW - Thermography
KW - Super resolution
KW - NDT
KW - Inspection
KW - Internal defects
KW - DMD
KW - DLP
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570551
DO - https://doi.org/10.1038/s41598-023-30494-2
SN - 2045-2322
VL - 13
SP - 1
EP - 13
PB - Nature Research
AN - OPUS4-57055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Editorial: Special Issue “Advanced Pulse Laser Machining Technology"
N2 - “Advanced Pulse Laser Machining Technology” is a rapidly growing field that can be tailored to special industrial and scientific applications. This is significantly driven by the availability of high-repetition-rate laser sources and novel beam delivery concepts.
KW - Editorial
KW - Pulse Laser
KW - Laser Machining
KW - Ultrashort laser pulses
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568410
DO - https://doi.org/10.3390/ma16020819
SN - 1996-1944
VL - 16
IS - 2
SP - 1
EP - 4
PB - MDPI
CY - Basel
AN - OPUS4-56841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krankenhagen, Rainer
T1 - Influence of Moisture in Concrete on the Photothermal Response—A New Approach for a Measurement Method?
N2 - Recently, the photothermal determination of the thermophysical properties of concrete under lab conditions was reported. Their values are mainly needed to look at the energy consumption of buildings. Additionally, changes in their values in relation to the initial state might also be a good indicator for material quality or for moisture. The present contribution explains the photothermal method in a more general way to indicate the potential for on-site application. Secondly, a special application case is regarded: the detection of moisture in concrete. Two concrete samples were soaked with water, followed by a drying period, to obtain different levels of water penetration. The water contents were determined by weighing, and the photothermal response was measured. The results show a large influence on the measured temperature transients, which is larger than expected from the original simple model. They clearly provide two points: the photothermal method is suited to detect moisture in concrete, but the magnitude of the actual measurement effect is not yet understood.
KW - Thermal effusivity
KW - Thermal conductivity
KW - Moisture
KW - Reflectivity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570439
DO - https://doi.org/10.3390/app13052768
VL - 13
IS - 5
SP - 1
EP - 18
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-57043
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rüdenauer, I.
A1 - Quack, D.
A1 - Schlegel, Moritz-Caspar
T1 - kWh versus Euro – What is the most effective way to inform about efficient products?
N2 - Energy efficient products often have a higher purchase price than less efficient alternatives. However, the life cycle costs are often lower due to the lower operating costs. From a purely economic point of view, efficient appliances are not only more ecological but often also more economical and, accordingly, should be purchased more frequently than less efficient appliances. However, this is not always the case. Information deficits are one of the major reasons of this discrepancy: the purchase price is visible during the purchasing process, but the follow-up costs are not, at least not in their exact amount. The EU Energy Label can be considered as a solution to close this gap. During the past decades, there has been a discussion on whether it would be better to communicate the monetary costs associated with energy consumption, since their calculation by the consumer is difficult or needs a high level of cognitive effort.
In this study, experiments and field studies on a total of 19 product groups were evaluated with regard to the question of whether the indication of costs instead of physical units affects the decision-making process of the consumer. It has been assessed under which circumstances it might positively influence the purchase decision of the customer, i.e. helping him or her to arrive at a more “energy efficient” decision. Overall, the results indicate that monetary claims possibly exceed the effect of claims on a physical basis when the costs or the differences between the alternatives available seem “relevant” to the consumer.
T2 - EEDAL’21
CY - Toulouse, France
DA - 01.06.2021
KW - Energy Labelling
KW - Ecodesign
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570454
SN - 978-92-76-99908-9
DO - https://doi.org/10.2760/356891
SP - 358
EP - 367
AN - OPUS4-57045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Veh, G.
A1 - Lützow, N.
A1 - Tamm, J.
A1 - Luna, L. V.
A1 - Hugonnet, R.
A1 - Vogel, Kristin
A1 - Geertsema, M.
A1 - Clague, J. J.
A1 - Korup, O.
T1 - Less extreme and earlier outbursts of ice-dammed lakes since 1900
N2 - Episodic failures of ice-dammed lakes have produced some of the largest floods in history, with disastrous consequences for communities in high mountains. Yet, estimating changes in the activity of ice-dam failures through time remains controversial because of inconsistent regional flood databases. Here, by collating 1,569 ice-dam failures in six major mountain regions, we systematically assess trends in peak discharge, volume, annual timing and source elevation between 1900 and 2021. We show that extreme peak flows and volumes (10 per cent highest) have declined by about an order of magnitude over this period in five of the six regions, whereas median flood discharges have fallen less or have remained unchanged.
Ice-dam floods worldwide today originate at higher elevations and happen about six weeks earlier in the year than in 1900. Individual ice-dammed lakes with repeated outbursts show similar negative trends in magnitude and earlier occurrence, although with only moderate correlation to glacier thinning8. We anticipate that ice dams will continue to fail in the near future, even as glaciers thin and recede. Yet widespread deglaciation, projected for nearly all regions by the end of the twenty-first century9, may bring most outburst activity to a halt.
KW - Outburst floods
KW - Bayesian hierachical modelling
KW - Trends in extreme events
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570529
DO - https://doi.org/10.1038/s41586-022-05642-9
VL - 614
IS - 7949
SP - 701
EP - 707
AN - OPUS4-57052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kraft, Sebastian
A1 - Schille, J.
A1 - Bonse, Jörn
A1 - Löschner, U.
A1 - Krüger, Jörg
T1 - X‑ray emission during the ablative processing of biological materials by ultrashort laser pulses
N2 - The ablative laser processing with ultrashort pulsed laser beams may cause secondary emission of hazardous X-rays. While the effect has recently been proven to be considered in working safety regulations when processing technical materials, such as metals, the X-ray emission rates during the ablative processing of biological tissue materials are widely unexplored yet.
Therefore, biological materials like water, isotonic saline solution, pig eyes, and human teeth were ablated with ultrashort laser pulses of 1030 nm wavelength, 600 fs pulse duration and 5 kHz pulse repetition rate, aiming to mimic typical surgery situations. Simultaneously, in-situ X-ray dose rate measurements were performed at a short distance from the plasma to display potential X-ray emission. For all four studied biological materials, our measurements prove the secondary emission of laser-induced X-rays.
KW - Ultrashort pulsed laser
KW - Laser-induced X-ray emission
KW - Ophthalmology
KW - Dentistry
KW - Secondary hazard
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569960
DO - https://doi.org/10.1007/s00339-023-06440-4
SN - 0947-8396
VL - 129
IS - 3
SP - 1
EP - 8
PB - Springer
AN - OPUS4-56996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xing, N.
A1 - Höfler, T.
A1 - Hearn, C. J.
A1 - Nascimento, M.
A1 - Camps Paradell, G.
A1 - McMahon, Dino Peter
A1 - Kunec, D.
A1 - Osterrieder, N.
A1 - Cheng, H. H.
A1 - Trimpert, J.
T1 - Fast-forwarding evolution - Accelerated adaptation in a proofreading-deficient hypermutator herpesvirus
N2 - Evolution relies on the availability of genetic diversity for fitness-based selection. However, most deoxyribonucleic acid (DNA) viruses employ DNA polymerases (Pol) capable of exonucleolytic proofreading to limit mutation rates during DNA replication. The relative genetic stability produced by high-fidelity genome replication can make studying DNA virus adaptation and evolution an intensive endeavor, especially in slowly replicating viruses. Here, we present a proofreading-impaired Pol mutant (Y547S) of Marek’s disease virus that exhibits a hypermutator phenotype while maintaining unimpaired growth in vitro and wild-type (WT)-like pathogenicity in vivo. At the same time, mutation frequencies observed in Y547S virus populations are 2–5-fold higher compared to the parental WT virus. We find that Y547S adapts faster to growth in originally non-permissive cells, evades pressure conferred by antiviral inhibitors more efficiently, and is more easily attenuated by serial passage in cultured cells compared to WT. Our results suggest that hypermutator viruses can serve as a tool to accelerate evolutionary processes and help identify key genetic changes required for adaptation to novel host cells and resistance to antiviral therapy. Similarly, the rapid attenuation achieved through adaptation of hypermutators to growth in cell culture enables identification of genetic changes underlying attenuation and virulence, knowledge that could practically exploited, e.g. in the rational design of vaccines.
KW - Polymerase mutant
KW - Proofreading deficient
KW - Hypermutation
KW - Adaption
KW - DNA polymerase
KW - Marek's Disease Virus
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565631
DO - https://doi.org/10.1093/ve/veac099
SN - 2057-1577
VL - 8
IS - 2
SP - 1
EP - 11
PB - Oxford University Press
CY - Oxford, UK
AN - OPUS4-56563
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maisels, A.
A1 - Hiller, A.
A1 - Simon, Franz-Georg
T1 - Chemical Recycling for Plastic Waste: Status and Perspectives
N2 - Industrial-scale mechanical recycling of plastics has been established for years, but has technical and economic limits. Chemical recycling processes lead back to monomers or to the raw materials, so that in the end new goods can be produced for all areas of application of plastics. The variety of chemical recycling processes is large. The capacities of the plants are still low today. The profitability of the plants is strongly influenced by the price of oil; the profitability limit is currently between 50 and 60 US $ per barrel.
KW - Chemical recycling
KW - Plastic waste
KW - Circular economy
KW - Pyrolysis
KW - Solvolysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565700
DO - https://doi.org/10.1002/cben.202200024
SN - 2196-9744
VL - 9
IS - 6
SP - 541
EP - 555
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-56570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bulling, Jannis
A1 - Jurgelucks, B.
A1 - Prager, Jens
A1 - Walther, A.
T1 - Defect reconstruction in a two-dimensional semi-analytical waveguide model via derivative-based optimization
N2 - This paper considers an indirect measurement approach to reconstruct a defect in a two-dimensional waveguide model for a non-destructive ultrasonic inspection via derivative-based optimization. The propagation of the mechanical waves is simulated by the scaled boundary finite element method that builds on a semi-analytical approach. The simulated data are then fitted to given data associated with the reflected waves from a defect which is to be reconstructed. For this purpose, we apply an iteratively regularized Gauss-Newton method in combination with algorithmic differentiation to provide the required derivative information accurately and efficiently. We present numerical results for three kinds of defects, namely, a crack, delamination, and corrosion. The objective function and the properties of the reconstruction method are investigated. The examples show that the parameterization of the defect can be reconstructed efficiently as well as robustly in the presence of noise.
KW - Mechanical waves
KW - Corrosion
KW - Finite-element analysis
KW - Ultrasonic testing
KW - Nondestructive testing techniques
KW - Symbolic computation
KW - Materials analysis
KW - MATLAB
KW - Newton Raphson method
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565485
DO - https://doi.org/10.1121/10.0013574
VL - 152
IS - 2
SP - 1217
EP - 1229
PB - AIP Publ.
CY - Melville, NY
AN - OPUS4-56548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Soraya
A1 - Jaut, Valerie
A1 - Schneider, Rudolf
T1 - Ergometrine sensing in rye flour by a magnetic bead-based immunoassay followed by flow injection analysis with amperometric detection
N2 - A certain group of mycotoxins, the ergot alkaloids, has caused countless deaths throughout human history. They are found in rye and other cereals and ingesting contaminated foods can cause serious health problems. To identify contaminated food exceeding the legal limits for ergot alkaloids, a portable and cost-effective test system is of great interest to the food industry. Rapid analysis can be achieved by screening for a marker compound, for which we chose ergometrine. We developed a magnetic bead-based immunoassay for ergometrine with amperometric detection in a flow injection system using a handheld potentiostat and a smartphone. With this assay a limit of detection of 3 nM (1 μg/L) was achieved. In spiked rye flour, ergometrine levels from 25 to 250 μg/kg could be quantified. All results could be verified by optical detection. The developed assay offers great promise to meet the demand for on-site ergometrine detection in the food industry.
KW - Ergot alkaloids
KW - Amperometry
KW - Magnetic beads
KW - Immunoassay
KW - Food analysis
KW - Fow injection analysis
KW - Mycotoxins
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565906
DO - https://doi.org/10.1016/j.talanta.2022.124172
SN - 0039-9140
N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S.
VL - 254
IS - 124172
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-56590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Malakhov, A.
A1 - Epishin, A.
A1 - Denisov, I.
A1 - Saikov, I.
A1 - Nolze, Gert
T1 - Morphology and Structure of Brass–Invar Weld Interface after Explosive Welding
N2 - This paper presents the results of a study of the morphology and structure at the weld interface in a brass–Invar bimetal, which belongs to the class of so-called thermostatic bimetals, or thermobimetals. The structure of the brass–Invar weld interface was analyzed using optical microscopy and scanning electron microscopy (SEM), with the use of energy-dispersive X-ray (EDX) spectrometry and back-scattered electron diffraction (BSE) to identify the phases. The distribution of the crystallographic orientation of the grains at the weld interface was obtained using an e-Flash HR electron back-scatter diffraction (EBSD) detector and a forward-scatter detector (FSD). The results of the study indicated that the weld interface had the wavy structure typical of explosive welding. The wave crests and troughs showed the presence of melted zones consisting of a disordered Cu–Zn–Fe–Ni solid solution and undissolved Invar particles. The pattern quality map showed that the structure of brass and Invar after explosive welding consisted of grains that were strongly elongated towards the area of the highest intensive plastic flow. In addition, numerous deformation twins, dislocation accumulations and shear bands were observed. Thus, based on the results of this study, the mechanism of Cu–Zn–Fe–Ni structure formation can be proposed.
KW - Explosive welding
KW - Thermobimetal
KW - Grain structure
KW - Brass
KW - Invar
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565964
DO - https://doi.org/10.3390/ma15238587
SN - 1996-1944
VL - 15
IS - 23
SP - 1
EP - 10
PB - MDPI
AN - OPUS4-56596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Katrin
A1 - Schmitt Rahner, M.
A1 - Stolzenberg, U.
A1 - Kraft, Sebastian
A1 - Bonse, Jörn
A1 - Feist, C.
A1 - Albrecht, D.
A1 - Pullner, B.
A1 - Krüger, Jörg
T1 - Worst-case X-ray photon energies in ultrashort pulse laser processing
N2 - Ultrashort pulse laser processing can result in the secondary generation of unwanted X-rays if a critical laser irradiance of about 10^13 W/cm^2 is exceeded. Spectral X-ray emissions were investigated during the processing of tungsten and steel using three complementary spectrometers (based on CdTe and silicon drift detectors) simultaneously for the identification of a worst-case spectral scenario. Therefore, maximum X-ray photon energies were determined, and corresponding dose equivalent rates were calculated. An ultrashort pulse laser workstation with a pulse duration of 274 fs, a center wavelength of 1030 nm, pulse repetition rates between 50 kHz and 200 kHz, and a Gaussian laser beam focused to a spot diameter of 33 µm was employed in a single pulse and burst laser operation mode. Different combinations of laser pulse energy and repetition rate were utilized, keeping the average laser power constant close to the maximum power of 20 W. Peak irradiances ranging from 7.3 × 10^13 W/cm^2 up to 3.0 × 10^14 W/cm^2 were used. The X-ray dose equivalent rate increases for lower repetition rates and higher pulse energy if a constant average power is used. Laser processing with burst mode significantly increases the dose rates and the X-ray photon energies. A maximum X-ray photon energy of about 40 keV was observed for burst mode processing of tungsten with a repetition rate of 50 kHz and a peak irradiance of 3 × 10^14 W/cm^2.
KW - Ultrashort pulsed laser
KW - X-ray emission
KW - X-ray spectrum
KW - X-ray energies
KW - Radiation protection
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566176
DO - https://doi.org/10.3390/ma15248996
VL - 15
IS - 24
SP - 1
EP - 17
PB - MDPI
AN - OPUS4-56617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kinne, R. W.
A1 - Gunnella, F.
A1 - Kunisch, E.
A1 - Heinemann, S.
A1 - Nies, B.
A1 - Maenz, S.
A1 - Horbert, V.
A1 - Illerhaus, Bernhard
A1 - Huber, R.
A1 - Firkowska-Boden, I.
A1 - Bossert, J.
A1 - Jandt, K. D.
A1 - Sachse, A.
A1 - Bungartz, M.
A1 - Brinkmann, O.
T1 - Performance of calcium phosphate cements in the augmentation of sheep vertebrae - An ex vivo study
N2 - Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactideco-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2–4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5). Untouched (L1) and empty vertebrae (L2) served as controls. Cement performance was analyzed using micro-computed tomography, histology, and biomechanical testing. Extrusion was comparable for Paste-CPC(-PLGA) and PMMA, but significantly lower for CPC + PLGA. Compressive strength and Young’s modulus were similar for Paste-CPC and PMMA, but significantly higher compared to those for empty defects and/or CPC + PLGA. Expectedly, all experimental groups showed significantly or numerically lower compressive strength and Young’s modulus than those of untouched controls. Ready-to-use Paste-CPC demonstrates a performance similar to that of PMMA, but improved biomechanics compared to those of water-based CPC + PLGA, expanding the therapeutic arsenal for bone defects. O, significantly lower extrusion of CPC + PLGA fibers into adjacent lumbar spongiosa may help to reduce the risk of local extrusion in spinal surgery.
KW - Sheep
KW - PMMA
KW - Calcium phosphate bone cement
KW - Oil-based
KW - Ready-to-use
KW - Water-based
KW - Micro-CT
KW - Compressive strength
KW - Young’s modulus
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569072
DO - https://doi.org/10.3390/ma14143873
SN - 1996-1944
VL - 14
IS - 14
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-56907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mitu, M.
A1 - Razus, D.
A1 - Schröder, Volkmar
T1 - Laminar burning velocities of hydrogen-blended methane-air and natural gas-air mixtures, calculated from the early stage of p(t) records in a spherical vessel
N2 - The flammable hydrogen-blended methane–air and natural gas–air mixtures raise specific safety and environmental issues in the industry and transportation; therefore, their explosion characteristics such as the explosion limits, explosion pressures, and rates of pressure rise have significant importance from a safety point of view. At the same time, the laminar burning velocities are the most useful parameters for practical applications and in basic studies for the validation of reaction mechanisms and modeling turbulent combustion. In the present study, an experimental and numerical study of the effect of hydrogen addition on the laminar burning velocity (LBV) of methane–air and natural gas–air mixtures was conducted, using mixtures with equivalence ratios within 0.90 and 1.30 and various hydrogen fractions rH within 0.0 and 0.5. The experiments were performed in a 14 L spherical vessel with central ignition at ambient initial conditions. The LBVs were calculated from p(t) data, determined in accordance with EN 15967, by using only the early stage of flame propagation. The results show that hydrogen addition determines an increase in LBV for all examined binary flammable mixtures. The LBV variation versus the fraction of added hydrogen, rH, follows a linear trend only at moderate hydrogen fractions. The further increase in rH results in a stronger variation in LBV, as shown by both experimental and computed LBVs. Hydrogen addition significantly changes the thermal diffusivity of flammable CH4–air or NG–air mixtures, the rate of heat release, and the concentration of active radical species in the flame front and contribute, thus, to LBV variation.
KW - Hydrogen
KW - Methane
KW - Natural gas
KW - Laminar burning velocity (LBV)
KW - Closed vessel combustion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569083
DO - https://doi.org/10.3390/en14227556
SN - 1996-1073
VL - 14
IS - 22
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-56908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neuhold, S.
A1 - Algermissen, D.
A1 - Drissen, P.
A1 - Adamczyk, Burkart
A1 - Presoly, P.
A1 - Sedlazeck, K. P.
A1 - Schenk, J.
A1 - Raith, J. G.
A1 - Pomberger, R.
A1 - Vollprecht, D.
T1 - Tailoring the FeO/SiO2 Ratio in Electric Arc Furnace Slags to Minimize the Leaching of Vanadium and Chromium
N2 - Based on recently published research on leaching control mechanisms in electric arc furnace (EAF) slags, it is assumed that a FeO/SiO2 ratio of around one leads to low leached V and Cr concentrations. This ratio influences the mineral phase composition of the slag toward higher amounts of spinel and a lower solubility of calcium silicate phases by suppressing the formation of magnesiowuestite and highly soluble calcium silicate phases. To evaluate this hypothesis, laboratory and scaled up tests in an EAF pilot plant were performed on slag samples characterized by elevated V and Cr leaching and a high FeO/SiO2 ratio. Prior to the melting experiments, the optimum FeO/SiO2 ratio was calculated via FactSageTM. In the melting experiments, the ratio was adjusted by adding quartz sand, which also decreased the basicity (CaO/SiO2) of the slag. As a reference, remelting experiments without quartz sand addition were conducted and additionally, the influence of the cooling rate of the slag was examined. The remelted (without quartz sand) and the remelted modified slags (with quartz sand) were analyzed chemically and mineralogically and the leaching behavior was investigated. The modification of the slags yielded a minimized release of V and Cr, supporting the hypothesis that the FeO/SiO2 ratio influences the mineralogy and the leaching behavior.
KW - Electric arc furnace (EAF) slags
KW - FactSageTM calculations
KW - Leaching control mechanisms
KW - Melting experiments
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571517
DO - https://doi.org/10.3390/app10072549
VL - 10
IS - 7
SP - 1
EP - 18
PB - MDPI
AN - OPUS4-57151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Flierl, Lukas
A1 - Rienitz, Olaf
A1 - Vogl, Jochen
A1 - Pramann, Axel
T1 - An advancement of the gravimetric isotope mixture method rendering the knowledge of the spike purity superfluous
N2 - The gravimetric isotope mixture method is the primary method to determine absolute isotope ratios. This method, however, depends on the existence of suitable spike materials and knowledge of their purities. Determining the purity of the spikes can be tedious and labour-intensive. In this publication, an advancement of the gravimetric isotope mixture method, rendering the determination of the purity of the spike materials unnecessary, is presented. The advancement combines mass spectrometry and ion chromatography leading to an approach being independent of the purity of the spike materials. In the manuscript the mathematical background and the basic idea of the novel approach are described using a two-isotope system like copper or lithium.
KW - Isotope amount ratios
KW - Metrology
KW - Mass spectrometry
KW - Ion chromatography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608726
DO - https://doi.org/10.1007/s00216-024-05465-9
SP - 5325
EP - 5333
PB - Springer Science and Business Media LLC
AN - OPUS4-60872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolar, Tomislav
A1 - Pearce, Ben K.D.
A1 - Etter, Martin
A1 - Truong, Khai-Nghi
A1 - Ostojić, Tea
A1 - Krajnc, Andraž
A1 - Mali, Gregor
A1 - Rossi, Barbara
A1 - Molčanov, Krešimir
A1 - Lončarić, Ivor
A1 - Meštrović, Ernest
A1 - Užarević, Krunoslav
A1 - Grisanti, Luca
T1 - Base-pairing of uracil and 2,6-diaminopurine: from cocrystals to photoreactivity
N2 - We show that the non-canonical nucleobase 2,6-diaminopurine (D) spontaneously base pairs with uracil (U) in water and the solid state without the need to be attached to the ribose-phosphate backbone. Depending on the reaction conditions, D and U assemble in thermodynamically stable hydrated and anhydrated D-U base-paired cocrystals. Under UV irradiation, an aqueous solution of D-U base-pair undergoes photochemical degradation, while a pure aqueous solution of U does not. Our simulations suggest that D may trigger the U photodimerization and show that complementary base-pairing modifies the photochemical properties of nucleobases, which might have implications for prebiotic chemistry.
KW - Mechanochemistry
KW - In situ monitoring
KW - Cocrystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608622
DO - https://doi.org/10.1016/j.isci.2024.109894
VL - 27
IS - 6
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-60862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Davison, Nathan
A1 - Hemingway, Jack M.
A1 - Wills, Corinne
A1 - Stolar, Tomislav
A1 - Waddell, Paul G.
A1 - Dixon, Casey M.
A1 - Barron, Luke
A1 - Dawson, James A.
A1 - Lu, Erli
T1 - Mechanochemical Synthesis of a Sodium Anion Complex [Na+(2,2,2-cryptand)Na–] and Studies of Its Reactivity: Two-Electron and One-Electron Reductions
N2 - Group 1 metal molecular chemistry is dominated by a +1 oxidation state, while a 0 oxidation state is widespread in the metals. A more exotic, yet still available, oxidation state of group 1 metal is −1, i.e., alkalide. Reported as early as the 1970s, the alkalides appear in every modern inorganic chemistry textbook as an iconic chemical curiosity, yet their reactivity remains unexplored. This is due to their synthetic hurdles. In this work, we report the first facile synthesis of the archetypical alkalide complex, [Na+(2,2,2-cryptand)Na–], which allows us to unveil a versatile reactivity profile of this once exotic species.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608632
DO - https://doi.org/10.1021/acs.inorgchem.4c02914
VL - 63
IS - 32
SP - 15247
EP - 15258
PB - American Chemical Society (ACS)
AN - OPUS4-60863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giv, Ali Nemati
A1 - Asante, Bright
A1 - Yan, Libo
A1 - Kasal, Bohumil
T1 - Shear performance and durability of adhesively bonded spruce wood-concrete composite joints: Effects of indoor and outdoor environmental conditions, mechanical load, and their coupled effect
N2 - A long-term study was conducted on double-lap spruce wood-concrete joints to investigate their shear strength and stiffness over a 12-month period. These joints were manufactured using both wet and dry processes, each incorporating two adhesive types for bonding the wood to the concrete: a brittle epoxy and a ductile polyurethane (PUR). The experimental design exposed the joints to three specific long-term environments: (1) outdoor exposure, (2) indoor conditions with applied load, and (3) outdoor conditions with applied load. The wood concrete joints exposed to outdoor conditions were subjected to destructive shear testing at intervals of 0 (serving as the reference sample), 2, 4, 6, and 12 months, respectively. For joints subjected to both indoor and outdoor conditions with shear loading, the shear deformation of joints was monitored continuously over the 12 months before performing the destructive tests. A gradual reduction in the shear stiffness and strength of dry joints (produced using the dry bond method) exposed to outdoor conditions was observed over a 12-month period, primarily due to bond failure at the concrete-adhesive interface. The wet joints exhibited no degradation in shear stiffness and strength across long-term conditions over the same period. The bond failure observed in dry joints was predominantly associated with stresses arising from dimensional changes in the wood. No degradation was found in the cross-linking density of the adhesive or in the concrete’s compressive stiffness and strength.
KW - Adhesively bonded joints
KW - Long-term study
KW - Ductile PUR
KW - Brittle epoxy
KW - Outdoor condition
KW - Mechanical load
KW - Indoor condition
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608878
DO - https://doi.org/10.1016/j.conbuildmat.2024.136905
VL - 436
SP - 1
EP - 22
PB - Elsevier BV
AN - OPUS4-60887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Hildebrandt, N.
T1 - Near infrared quantum dots for biosensing and bioimaging
N2 - Quantum dots (QDs) possess unique optoelectronic properties, which make them very attractive to be used as optical probes in biosensing and bioimaging applications. The strong absorbance and light scattering of biological compounds like tissue and blood in the visible range pose a problem. However, if optical probes emitting in the near-infrared (NIR) range are used, scattering, absorption, and autofluorescence of biological components are strongly reduced. This allows for an increased light penetration depth and higher spatial and temporal resolution for the investigation of biological processes. The synthesis and application of NIR emitting QDs is a fast-growing research field and the benefits of using QDs were demonstrated for a variety of applications, such as photoelectrochemical biosensor, in vivo vascular imaging, and fluorescence-guided surgery. This article reviews the state-of-the-art developments in the preparation of NIR/IR QDs and highlights the latest research about their utilization in biosensing and bioimaging applications.
KW - Quantum dots
KW - Near-infrared
KW - Biosensing
KW - Bioimaging
KW - NIR-II / SWIR
KW - Advanced nanomaterials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609708
SN - 0165-9936
DO - https://doi.org/10.1016/j.trac.2024.117922
VL - 180
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-60970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mellios, Nikolaos
A1 - Kruschwitz, Sabine
A1 - Spyrdis, Panagiotis
T1 - Performance Prediction of Anchors in SFRC using Minimally Invasive and Non‐Destructive Techniques
N2 - AbstractFastenings are crucial for the upgrade of existing structures, by either enhancing structural components or modernising and expanding structures and structural systems. Whilst concrete is prevailing in the existing building stock, new types of concrete composites are increasingly used to improve the sustainability and overall structural performance of built assets. The addition of short dispersed fibres is a material technology with several applications. This paper addresses the synergy of fastening elements, introducing localised loads in concrete substrates, and of fibres, particularly in terms of the fibre orientation and density in the load application area, which is a significant quality aspect. The possibility to forecast this synergy based on non‐destructive or minimally invasive testing methods is an efficient tool to increase confidence in the design load‐bearing performance of the anchorages. Initially, previous literature and own investigations on such techniques are presented. Furthermore, a methodology is presented on associating such information to predict a single anchor's resistance on the basis of sophisticated non‐linear analyses and testing with engineered fibres alignments.
T2 - Annual Meeting of the European-Association-on-Quality-Control-of-Bridges-and-Structures (EUROSTRUCT)
CY - Vienna, Austria
DA - 25.09.2023
KW - Minimally-invasive evaluation
KW - Fastenings
KW - Anchorage to concrete
KW - Steel fibre reinforced concrete
KW - Non-destructive evaluation NDE
KW - Non-destructive testing NDT
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609223
DO - https://doi.org/10.1002/cepa.2115
VL - 69
IS - 5
SP - 1455
EP - 1463
PB - Wiley
AN - OPUS4-60922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmitt, M.
A1 - Casperson, Ralf
A1 - Baensch, F.
A1 - Müller, D.
T1 - Nationale, europäische und internationale Normung in der zerstörungsfreien Prüfung
N2 - Normung und Standardisierung in der zerstörungsfreien Prüfung finden auf nationaler, europäischer und internationaler Ebene statt. Die Übernahme von Leitungsfunktionen in diesen Gremien erzeugt die Möglichkeit der Steuerung von Themen und Inhalten der relevanten Normen. Das persönliche Engagement der Fachexpert*innen in den nationalen Gremien und den europäischen und internationalen Arbeitsgruppen ist ein zusätzlicher Faktor für die inhaltliche Korrektheit und die inhaltliche Ausrichtung der Norm. Denn wer nicht normt, wird genormt und muss letztlich Normen anwenden, die andere entsprechend ihrer eigenen Interessen gestaltet haben. Voraussetzung für die Teilnahme in europäischen und internationalen Normungsgremien ist die Mitwirkung in den entsprechenden DINSpiegelgremien, welche die europäischen (CEN) und internationalen (ISO) Aktivitäten spiegeln und die Fachexpert*innen für die Mitarbeit autorisieren.
Auf internationaler Ebene findet die Normungsarbeit in den technischen Komitees ISO/TC 135 “Non-destructive testing” und ISO/TC 44/SC 5 “Testing and inspection of welds” und ihren Arbeitsgruppen statt. Das europäische Pendant ist das CEN/TC 138 “Zerstörungsfreie Prüfverfahren” mit seinen Arbeitsgremien. Die DINSpiegelgremien sind für die deutsche Mitarbeit in diesen Gremien und die inhaltliche Bewertung der Norm-Entwürfe zuständig.
T2 - DGZfP Jahrestagung 2024
CY - Osnabrück, Germany
DA - 05.05.2024
KW - Normung
KW - Zerstörungsfreie Prüfung
KW - Qualifizierung
KW - Qualitätssicherung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600726
DO - https://doi.org/10.58286/29496
IS - 5
SP - 1
EP - 6
AN - OPUS4-60072
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Scholz, Philipp
T1 - Sequential Extraction of Incineration Bottom Ash: Conclusions Regarding Ecotoxicity
N2 - The classification of incineration bottom ash (IBA) as hazardous or non-hazardous according to ecotoxic hazard property HP14 is still under debate. In this context, only the compounds of Zn and Cu with the hazard statement code H410 are of relevance. With an approach based on the grouping of substances, it was shown that such substances are either readily water-soluble or slightly and sparingly soluble. The concentrations of readily soluble Cu and Zn compounds in IBA are far below the cut-off value of 0.1%. Slightly and sparingly soluble Zn and Cu compounds could be quantified in the first fraction of a four-step sequential extraction procedure. With the results from the complete sequence, the dimensionless synthesis toxicity index (STI) was calculated and was in the range of 494 to 1218 for the four investigated IBA samples. It was concluded that IBA can usually be classified as non-hazardous.
KW - Incineration bottom ash
KW - Hazard properties
KW - Ecotoxicity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605262
DO - https://doi.org/10.3390/app14135541
SN - 2076-3417
VL - 14
IS - 13
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-60526
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scales, B. S.
A1 - Hasenrück, C.
A1 - Moldaenke, L.
A1 - Hassa, J.
A1 - Rückert-Reed, C.
A1 - Rummel, C.
A1 - Völkner, C.
A1 - Rynek, R.
A1 - Busche, T.
A1 - Kalinowski, J.
A1 - Jahnke, A.
A1 - Schmitt-Jansen, M.
A1 - Wendt-Potthoff, K.
A1 - Oberbeckmann, Sonja
T1 - Hunting for pigments in bacterial settlers of the Great Pacific Garbage Patch
N2 - The Great Pacific Garbage Patch, a significant collection of plastic introduced by human activities, provides an ideal environment to study bacterial lifestyles on plastic substrates. We proposed that bacteria colonizing the floating plastic debris would develop strategies to deal with the ultravioletexposed substrate, such as the production of antioxidant pigments. We observed a variety of pigmentation in 67 strains that were directly cultivated from plastic pieces sampled from the Garbage Patch. The genomic analysis of four representative strains, each distinct in taxonomy, revealed multiple pathways for carotenoid production. These pathways include those that produce
less common carotenoids and a cluster of photosynthetic genes. This
cluster appears to originate from a potentially new species of the Rhodobacteraceae family. This represents the first report of an aerobic anoxygenic photoheterotrophic bacterium from plastic biofilms. Spectral analysis showed that the bacteria actively produce carotenoids, such as betacarotene and beta-cryptoxanthin, and bacteriochlorophyll a. Furthermore, we discovered that the genetic ability to synthesize carotenoids is more common in plastic biofilms than in the surrounding water communities. Our findings suggest that plastic biofilms could be an overlooked source of bacteria-produced carotenoids, including rare forms. It also suggests that photoreactive molecules might play a crucial role in bacterial biofilm communities in surface water.
KW - Microplastics
KW - Biofilm
KW - Pigment
KW - Microorganisms
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605725
DO - https://doi.org/10.1111/1462-2920.16639
SN - 1462-2912
VL - 26
IS - 6
SP - e16639
PB - John Wiley & Sons Ltd.
AN - OPUS4-60572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bacurau, V. P.
A1 - Moreira, P. A. F. P.
A1 - Bertoli, G.
A1 - Andreoli, A. F.
A1 - Mazzer, E.
A1 - de Assis, F. F.
A1 - Gargarella, P.
A1 - Koga, G.
A1 - Stumpf, G. C.
A1 - Figueroa, S. J. A.
A1 - Widom, M.
A1 - Kaufman, M.
A1 - Fantin, Andrea
A1 - Cao, Y.
A1 - Freitas, R.
A1 - Miracle, D.
A1 - Coury, F. G.
T1 - Comprehensive analysis of ordering in CoCrNi and CrNi2 alloys
N2 - Chemical Short-Range Order (CSRO) has attracted recent attention from many researchers, creating intense debates about its impact on material properties.
The challenges lie in confirming and quantifying CSRO, as its detection proves exceptionally demanding, contributing to conflicting data in the literature regarding its true effects on mechanical properties. Our work uses highprecision calorimetric data to unambiguously prove the existence and, coupled with atomistic simulations, quantify the type of CSRO. This methodology allows us to propose a mechanism for its formation and destruction based on the heat evolution during thermal analysis and facilitates a precise identification of local ordering in CoCrNi alloys. Samples of CoCrNi (Co33Cr33Ni33) and CrNi2 (Cr33Ni66) alloys are fabricated in varying ordered states, extensively characterized via synchrotron X-ray diffraction, X-ray absorption spectroscopy, and transmission electron microscopy. Samples with considerably different ordered states are submitted to tensile tests with in-situ synchrotron X-ray diffraction. We demonstrate, despite inducing varied CSRO levels in CoCrNi, no significant alterations in overall mechanical behavior emerge.
However, the CrNi2 alloy, which undergoes long-range ordering, experiences significant shifts in yield strength, ultimate tensile stress and ductility.
KW - Mechanical properties
KW - Short-range ordering
KW - Calorimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611075
DO - https://doi.org/10.1038/s41467-024-52018-w
VL - 15
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Fabian
A1 - von der Au, Marcus
A1 - Gehrenkemper, Lennart
A1 - Meermann, Björn
T1 - An optimized method for PFAS analysis using HR–CS–GFMAS via GaF detection
N2 - The analysis of per- and polyfluoroalkyl substances (PFAS) via sum parameters like extractable organic fluorine (EOF) in combination with high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR–CS–GFMAS) is highly promising regarding fluorine sensitivity and selectivity. However, the HR–CS–GFMAS method includes several drying and heating steps which can lead to losses of volatile PFAS before the molecular formation step using e.g., GaF formation. Hence, the method leads to a strong discrimination of PFAS within the EOF depending on their physical/chemical properties and is therefore associated with reduced accuracy. To reduce this discrepancy and to indicate realistic PFAS pollution values, an optimization of the HR–CS–GFMAS method for PFAS analysis is needed. Hence, we determined fluorine response factors of several PFAS with different physical/chemical properties upon application of systematic optimization steps. We could therefore improve the method's sensitivity for PFAS analysis using a modifier drying pre-treatment step followed by a sequential injection of sample solutions. The highest improvement in sensitivity of volatile PFAS was shown upon addition of a Mg modifier during drying pre-treatment. Thereby, during optimization the relative standard deviation of fluorine response factors could be reduced from 55 % (initial method) to 27 % (optimized method) leading to a more accurate determination of organofluorine sum parameters. The method provides an instrumental LOD and LOQ of β(F) 1.71 μg/L and 5.13 μg/L, respectively. Further validation aimed to investigate several matrix effects with respect to water matrices. Here, substance-specific behavior was observed. For example, perfluorooctanoic acid (PFOA) which was used as calibrator, showed signal suppressions upon high chloride concentrations (>50 mg/L). Hence, a thorough separation of Cl from analytes during sample preparation is needed for accurate sum parameter analysis.
KW - PFAS
KW - GF-AAS
KW - Method optimization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610522
DO - https://doi.org/10.1016/j.talanta.2024.126811
VL - 281
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-61052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chronakis, Michail Ioannis
A1 - Meermann, Björn
A1 - von der Au, Marcus
T1 - The evolution of data treatment tools in single-particle and single-cell ICP-MS analytics
N2 - Single-particle inductively coupled plasma-mass spectrometry (sp-ICP-MS) is one of the most powerful tools in the thriving field of nanomaterial analysis. Along the same lines, single-cell ICP-MS (sc-ICP-MS) has become an invaluable tool in the study of the variances of cell populations down to a per-cell basis. Their importance and application fields have been listed numerous times, across various reports and reviews. However, not enough attention has been paid to the immense and ongoing development of the tools that are currently available to the analytical community for the acquisition, and more importantly, the treatment of single-particle and single-cell-related data. Due to the ever-increasing demands of modern research, the efficient and dependable treatment of the data has become more important than ever. In addition, the field of single-particle and single-cell analysis suffers due to a large number of approaches for the generated data—with varying levels of specificity and applicability. As a result, finding the appropriate tool or approach, or even comparing results, can be challenging. This article will attempt to bridge these gaps, by covering the evolution and current state of the tools at the disposal of sp-ICP-MS users.
Graphical Abstract
KW - Trend Article
KW - spICP-MS
KW - Data Tools
KW - scICP-MS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610539
DO - https://doi.org/10.1007/s00216-024-05513-4
SP - 1
EP - 7
PB - Springer Science and Business Media LLC
AN - OPUS4-61053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Golian, M. J.
A1 - Friedman, D. A.
A1 - Harrison, M.
A1 - McMahon, Dino Peter
A1 - Buellesbach, J.
T1 - Chemical and transcriptomic diversity do not correlate with ascending levels of social complexity in the insect order Blattodea
N2 - AbstractEusocial insects, such as ants and termites, are characterized by high levels of coordinated social organization. This is contrasted by solitary insects that display more limited forms of collective behavior. It has been hypothesized that this gradient in sociobehavioral sophistication is positively correlated with chemical profile complexity, due to a potentially increased demand for diversity in chemical communication mechanisms in insects with higher levels of social complexity. However, this claim has rarely been assessed empirically. Here, we compare different levels of chemical and transcriptomic complexity in selected species of the order Blattodea that represent different levels of social organization, from solitary to eusocial. We primarily focus on cuticular hydrocarbon (CHC) complexity, since it has repeatedly been demonstrated that CHCs are key signaling molecules conveying a wide variety of chemical information in solitary as well as eusocial insects. We assessed CHC complexity and divergence between our studied taxa of different social complexity levels as well as the differentiation of their respective repertoires of CHC biosynthesis gene transcripts. Surprisingly, we did not find any consistent pattern of chemical complexity correlating with social complexity, nor did the overall chemical divergence or transcriptomic repertoire of CHC biosynthesis genes reflect on the levels of social organization. Our results challenge the assumption that increasing social complexity is generally reflected in more complex chemical profiles and point toward the need for a more cautious and differentiated view on correlating complexity on a chemical, genetic, and social level.
KW - Chemical ecology
KW - Ecological genetics
KW - Entomology
KW - Evolutionary ecology
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608260
DO - https://doi.org/10.1002/ece3.70063
SN - 2045-7758
VL - 14
IS - 8
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-60826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hellemans, S.
A1 - Rocha, M. M.
A1 - Wang, M.
A1 - Romero Arias, J.
A1 - Aanen, D. K.
A1 - Bagnères, A.-G.
A1 - Buček, A.
A1 - Carrijo, T. F.
A1 - Chouvenc, T.
A1 - Cuezzo, C.
A1 - Constantini, J. P.
A1 - Constantino, R.
A1 - Dedeine, F.
A1 - Deligne, J.
A1 - Eggleton, P.
A1 - Evans, T. A.
A1 - Hanus, R.
A1 - Harrison, Mark C.
A1 - Harry, M.
A1 - Josens, G.
A1 - Jouault, C.
A1 - Kalleshwaraswamy, C. M.
A1 - Kaymak, E.
A1 - Korb, J.
A1 - Lee, C.-Y.
A1 - Legendre, F.
A1 - Li, H.-F.
A1 - Lo, N.
A1 - Lu, T.
A1 - Matsuura, K.
A1 - Maekawa, K.
A1 - McMahon, Dino Peter
A1 - Mizumoto, N.
A1 - Oliveira, D. E.
A1 - Poulsen, M.
A1 - Sillam-Dussès, D.
A1 - Su, N.-Y.
A1 - Tokuda, G.
A1 - Vargo, E. L.
A1 - Ware, J. L.
A1 - Šobotník, J.
A1 - Scheffrahn, R. H.
A1 - Cancello, E.
A1 - Roisin, Y.
A1 - Engel, M. S.
A1 - Bourguignon, T.
T1 - Genomic data provide insights into the classification of extant termites
N2 - The higher classification of termites requires substantial revision as the Neoisoptera, the most diverse termite lineage, comprise many paraphyletic and polyphyletic higher taxa. Here, we produce an updated termite classification using genomic-scale analyses. We reconstruct phylogenies under diverse substitution models with ultraconserved elements analyzed as concatenated matrices or within the multi-species coalescence framework. Our classification is further supported by analyses controlling for rogue loci and taxa, and topological tests. We show that the Neoisoptera are composed of seven family-level monophyletic lineages, including the Heterotermitidae Froggatt, Psammotermitidae Holmgren, and Termitogetonidae Holmgren, raised from subfamilial rank. The species-rich Termitidae are composed of 18 subfamily-level monophyletic lineages, including the new subfamilies Crepititermitinae, Cylindrotermitinae, Forficulitermitinae, Neocapritermitinae, Protohamitermitinae, and Promirotermitinae; and the revived Amitermitinae Kemner, Microcerotermitinae Holmgren, and Mirocapritermitinae Kemner. Building an updated taxonomic classification on the foundation of unambiguously supported monophyletic lineages makes it highly resilient to potential destabilization caused by the future availability of novel phylogenetic markers and methods. The taxonomic stability is further guaranteed by the modularity of the new termite classification, designed to accommodate as-yet undescribed species with uncertain affinities to the herein delimited monophyletic lineages in the form of new families or subfamilies.
KW - Termite
KW - Taxonomy
KW - Evolution
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608276
DO - https://doi.org/10.1038/s41467-024-51028-y
VL - 15
IS - 1
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-60827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - El Moutaouakil, H.
A1 - Fuchs, C.
A1 - Savli, E.
A1 - Heimann, Jan
A1 - Prager, Jens
A1 - Moll, J.
A1 - Tschöke, K.
A1 - Márquez Reyes, O.
A1 - Schackmann, O.
A1 - Memmolo, V.
A1 - Schneider, T.
T1 - Acquiring a Machine Learning Data Set for Structural Health Monitoring of Hydrogen Pressure Vessels at Operating Conditions using Guided Ultrasonic Waves
N2 - Hydrogen is an energy source of increasing importance. As hydrogen is very reactive to air and needs to be stored under high pressure, it is crucial to provide safe transportation and storage. Therefore, structural health monitoring, based on guided ultrasonic waves and machine learning methods, is used for Composite Overwrapped Pressure Vessels (COPVs) containing hydrogen. To acquire data that allows robust detection of COPV defects, there are two main process parameters to consider. These are the pressurization of the vessel and the temperature conditions at the vessel. This paper will focus on the derivation of a design of experiment (DoE) from the needs of various validation scenarios (e.g. concerning pressure, temperature or excitation frequency). Practical limitations must be considered as well. We designed experiments with multiple reversible damages at different positions. A network of 25 transducers, structured as five rings with five sensors in one line, is installed on a vessel. Guided ultrasonic waves are used via the pitch-catch procedure, which means that the transducers act pairwise as transmitter and receiver in order to measure all transmitterreceiver combinations. This leads to 600 signal paths, recorded by a Verasonics Vantage 64 LF data acquisition system. Finally, the influences of temperature and pressure within the acquired data set are going to be visualized.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Composite Overwrapped Pressure Vessel
KW - Hydrogen
KW - Guided Ultrasonic Waves
KW - Data Acquisition
KW - Pressurization
KW - Machine Learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607472
DO - https://doi.org/10.58286/29754
SN - 1435-4934
SP - 1
EP - 8
AN - OPUS4-60747
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Beate
A1 - Pfeiffer, Friedhelm
A1 - Remus, Daniela
A1 - Dyall-Smith, Mike
A1 - Kunte, Hans-Jörg
ED - Klepac-Ceraj, Vanja
T1 - Genome sequence of Pseudomonas silesiensis strain G3, a member of a bacterial consortium capable of polyethylene degradation
N2 - A consortium of landfill bacteria including strain G3 can break down polyethylene, a long-lasting plastic that accumulates in the environment. The complete genome sequence of strain G3 was determined by PacBio and Nanopore sequencing and consists of three circular replicons. Genome-based classification assigned strain G3 to the species Pseudomonas silesiensis.
KW - PE degradation
KW - Polyethylene
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611618
DO - https://doi.org/10.1128/mra.00138-24
SN - 2576-098X
VL - 13
IS - 11
SP - 1
EP - 3
PB - American Society for Microbiology
AN - OPUS4-61161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jasiuniene, E.
A1 - Yilmaz, Bengisu
A1 - Smagulova, D.
A1 - Bhat, G. A.
A1 - Cicenas, V.
A1 - Zukauskas, E.
A1 - Mazeika, L.
T1 - Non-Destructive Evaluation of the Quality of Adhesive Joints Using Ultrasound, X-ray, and Feature-Based Data Fusion
N2 - The aim of this work is to achieve reliable nondestructive evaluation (NDE) of adhesively bonded aerospace components by developing novel multidimensional data fusion techniques, which would combine the information obtained by ultrasonic and X-ray NDE methods. Separately, both NDE techniques have their advantages and limitations. The integration of data obtained from pulse echo immersion ultrasound testing and radiography holds immense potential to help improve the reliability of non-destructive evaluation. In this study, distinctive features obtained from single techniques, traditional ultrasonic pulse echo testing, and radiography, as well as fused images, were investigated and the suitability of these distinctive features and fusion techniques for improving the probability of defect detection was evaluated. For this purpose, aluminum single lap joints with brass inclusions were analyzed using ultrasound pulse echo and radiography techniques. The distinctive features were extracted from the data obtained, and images of features obtained by both techniques were fused together. Different combinations of features and fusion algorithms were investigated, considering the desire to automate data evaluation in the future.
KW - Data fusion
KW - Ultrasonics
KW - Radiography
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565789
DO - https://doi.org/10.3390/app122412930
VL - 12
IS - 24
SP - 1
EP - 20
PB - MDPI
AN - OPUS4-56578
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sechi, R.
A1 - Fackeldey, K.
A1 - Chewle, Surahit
A1 - Weber, M.
T1 - SepFree NMF: A toolbox for analyzing the kinetics of sequential spectroscopic data
N2 - This work addresses the problem of determining the number of components from sequential spectroscopic data analyzed by non-negative matrix factorization without separability assumption (SepFree NMF). These data are stored in a matrix M of dimension “measured times” versus “measured wavenumbers” and can be decomposed to obtain the spectral fingerprints of the states and their evolution over time. SepFree NMF assumes a memoryless (Markovian) process to underline the dynamics and decomposes M so that M = WH, with W representing the components’ fingerprints and H their kinetics. However, the rank of this decomposition (i.e., the number of physical states in the process) has to be guessed from pre-existing knowledge on the observed process. We propose a measure for determining the number of components with the computation of the minimal memory effect resulting from the decomposition; by quantifying how much the obtained factorization is deviating from the Markovian property, we are able to score factorizations of a different number of components. In this way, we estimate the number of different entities which contribute to the observed system, and we can extract kinetic information without knowing the characteristic spectra of the single components. This manuscript provides the mathematical background as well as an analysis of computer generated and experimental sequentially measured Raman spectra.
KW - Kinetics from experiments
KW - Separability assumption
KW - Sequential spectroscopic data
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559046
DO - https://doi.org/10.3390/a15090297
SN - 1999-4893
VL - 15
IS - 9
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fackeldey, K.
A1 - Röhm, J.
A1 - Niknejad, A.
A1 - Chewle, Surahit
A1 - Weber, M.
T1 - Analyzing Raman spectral data without separabiliy assumption
N2 - Raman spectroscopy is a well established tool for the analysis of vibration spectra, which then allow for the determination of individual substances in a chemical sample, or for their phase transitions. In the time-resolved-Raman-sprectroscopy the vibration spectra of a chemical sample are recorded sequentially over a time interval, such that conclusions for intermediate products (transients) can be drawn within a chemical process. The observed data-matrix M from a Raman spectroscopy can be regarded as a matrix product of two unknown matrices W and H, where the first is representing the contribution of the spectra and the latter represents the chemical spectra. One approach for obtaining W and H is the non-negative matrix factorization. We propose a novel approach, which does not need the commonly used separability assumption. The performance of this approach is shown on a real world chemical example.
KW - Non-negative matrix factorization
KW - NMF
KW - Raman spectra
KW - Separability condition
KW - PCCA+
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559051
DO - https://doi.org/10.1007/s10910-020-01201-7
SN - 1572-8897
VL - 59
SP - 575
EP - 596
PB - Springer Science + Business Media
CY - Dordrecht
AN - OPUS4-55905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Mathies, H.
T1 - The Impact of Weather Conditions on Biocides in Paints
N2 - Weather conditions affect biocides on exposed outer surfaces on constructions. Contact with water causes hydrolysis and leaching of substances. Ultraviolet radiation may induce photolysis. As a result, a mixture of biocidal active substances and transformation products can be emitted into the environment. In a semi-field study, leaching of the biocidal active substances terbutryn, diuron, octylisothiazolinone, carbendazim, and selected transformation products was observed for two paints containing either a white or a red pigment. Painted test panels were exposed to natural weathering for about 1.5 years. Runoff samples were analyzed during the course of the experiment.
At the end of the study, residues of biocidal active substances and transformation products were determined in sections of the test panels. Emissions of substances were mainly observed during the first few months of the experiments. Increased emissions of transformation products were observed during periods of increased global radiation and subsequent periods with relatively high amounts of driving rain. Different patterns of transformation products were observed, especially for terbutryn, both for paints containing different pigments and in experiments that were started in different periods of the year, as well as during different periods of the experiments.
KW - Substance release
KW - Construction products
KW - Biocides
KW - Transformation
KW - Weathering
KW - Driving rain
KW - Global radiation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560651
DO - https://doi.org/10.3390/ma15207368
VL - 15
IS - 20
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-56065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costabel, S.
A1 - Hiller, Thomas
A1 - Dlugosch, R.
A1 - Kruschwitz, Sabine
A1 - Müller Petke, M.
T1 - Evaluation of single-sided nuclear magnetic resonance technology for usage in geosciences
N2 - Because of its mobility and ability to investigate exposed surfaces, single-sided (SiS) nuclear magnetic resonance (NMR) technology enables new application fields in geosciences. To test and assess its corresponding potential, we compare longitudinal (T1) and transverse (T2) data measured by SiS NMR with those of conventional geoscientific laboratory NMR. We use reference sandstone samples covering a broad range of pore sizes. Our study demonstrates that the lower signal-to-noise ratio of SiS NMR data generally tends to slightly overestimated widths of relaxation time distributions and consequently pore size distributions. While SiS and conventional NMR produce very similar T1 relaxation data, unbiased SiS NMR results for T2 measurements can only be expected for fine material, i.e. clayey or silty sediments and soils with main relaxation times below 0.05s. This limit is given by the diffusion relaxation rate due to the gradient in the primary magnetic field associated with the SiS NMR. Above that limit, i.e. for coarse material, the relaxation data is strongly attenuated. If considering the diffusion relaxation time of 0.2 s in the numerical data inversion process, the information content >0.2s is blurred over a range larger than that of conventional NMR. However, our results show that principle range and magnitudes of the relaxation time distributions are reconstructed to some extent. Regarding these findings, SiS NMR can be helpful to solve geoscientific issues, e.g. to assess the hydro-mechanical properties of the walls of underground facilities or to provide local soil moisture data sets for calibrating indirect remote techniques on the regional scale. The greatest opportunity provided by the SiS NMR technology is the acquisition of profile relaxation data for rocks with significant bedding structures at the µm scale. With this unique feature, SiS NMR can support the understanding and modeling of hydraulic and diffusional anisotropy behavior of sedimentary rocks.
KW - Single-sided NMR
KW - Geosciences
KW - Nuclear magnetic resonance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561676
DO - https://doi.org/10.1088/1361-6501/ac9800
SN - 0957-0233
VL - 34
IS - 1
SP - 1
EP - 13
PB - IOP Publishing
AN - OPUS4-56167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - Hertwig, Andreas
T1 - Hybrid optical measurement technique for detection of defects in epitaxially grown 4H-SiC layers
N2 - Recent developments in power electronics require the use of new wide bandgap compound semiconductor. We demonstrate the use of the ellipsometry and white light interference microscopy to detect defects in epitaxially grown SiC layers on SiC substrates. Such hybrid optical metrology methods can be used to better understand the mechanism of the development of the defects as well as their effects on the material´s optoelectronic properties.
T2 - EOS Annual Meeting (EOSAM 2022)
CY - Porto, Portugal
DA - 12.09.2022
KW - Imaging ellipsometry
KW - White light interference microscopy
KW - Wide bandgap compound semiconductor
KW - Epitaxially grown 4H-SiC layers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561113
DO - https://doi.org/10.1051/epjconf/202226610001
VL - 266
SP - 1
EP - 2
AN - OPUS4-56111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shaheen, Sabahat
A1 - Hicke, Konstantin
T1 - Measurement of Geometric Phase using a φ-OTDR setup
N2 - Geometric phase showing sensitivity to changes in polarisation state and intensity of backscattered light is measured using a novel φ-OTDR setup based on coherent heterodyne detection. Principle is demonstrated using a polarisation scrambler inline a fiber-under-test.
T2 - Optical Fiber Sensors 2022
CY - Alexandria, Virginia, United States
DA - 29.08.2022
KW - Coherent Heterodyne
KW - Geometric Phase
KW - Distributed Fiber Optic Sensor
PY - 2022
SN - 978-1-957171-14-2
SP - W4.72
AN - OPUS4-56116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieber, M. J.
A1 - Wilke, M.
A1 - Appelt, O.
A1 - Oelze, Marcus
A1 - Koch-Müller, M.
T1 - Melting relations of Ca–Mg carbonates and trace element signature of carbonate melts up to 9 GPa – A proxy for melting of carbonated mantle lithologies
N2 - The most profound consequences of the presence of Ca–Mg carbonates (CaCO3–MgCO3) in the Earth’s upper mantle may be to lower the melting temperatures of the mantle and control the melt composition.
Low-degree partial melting of a carbonate-bearing mantle produces CO2-rich, silica-poor melts compositionally imposed by the melting relations of carbonates. Thus, understanding the melting relations in the CaCO3–MgCO3 system facilitates the interpretation of natural carbonate-bearing silicate systems.
We report the melting relations of the CaCO3–MgCO3 system and the partition coefficient of trace elements between carbonates and carbonate melt from experiments at high pressure (6 and 9 GPa) and temperature (1300–1800 ◦C) using a rocking multi-anvil press. In the absence of water, Ca–Mg carbonates are stable along geothermal gradients typical of subducting slabs. Ca–Mg carbonates (∼ Mg0.1–0.9Ca0.9–0.1CO3) partially melt beneath mid-ocean ridges and in plume settings. Ca–Mg carbonates melt incongruently, forming periclase crystals and carbonate melt between 4 and 9 GPa. Furthermore, we show that the rare earth element (REE) signature of Group-I kimberlites, namely strong REE fractionation and depletion of heavy REE relative to the primitive mantle, is resembled by carbonate melt in equilibrium with Ca-bearing magnesite and periclase at 6 and 9 GPa. This suggests that the dolomite–magnesite join of the CaCO3–MgCO3 system might be useful to approximate the REE signature of carbonate-rich melts parental to kimberlites.
KW - High pressure experiments
KW - Laser Ablation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561197
DO - https://doi.org/10.5194/ejm-34-411-2022
SN - 0935-1221
VL - 34
IS - 5
SP - 411
EP - 424
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-56119
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ewert, U.
A1 - Jaenisch, Gerd-Rüdiger
A1 - Schumacher, David
A1 - Bircher, B.
A1 - Meli, F.
A1 - Deresch, A.
T1 - EMPIR-Projekt NanoXSpot: Neue Normentwürfe für die Brennfleckmessung an Röntgenröhren im Makro-, Mikro- und Nanometerbereich für Hersteller und Anwender
N2 - Im Rahmen des EMPIR-Projektes NanoXSpot (Nanometre X-ray Focal Spot Measurement) werden rückführbare Messverfahren zur Bestimmung der Brennfleckgröße und -form von Röntgenröhren im Bereich von 100 nm bis 10 mm entwickelt, welche die Grundlage für die Erarbeitung mehrerer Normentwürfe bilden. Diese werden 2022 parallel bei ISO TC 135 (NDT) SC 5 (RT) und CEN TC 138 (NDT) WG 1 (RT) eingereicht. Entsprechende Normen werden auch bei ASTM vorgestellt. Die Norm EN 12543-4 (Kantenmethode) wird umgeschrieben für die Messung von Brennflecken von 1 μm – 10 mm durch Auswertung von Loch- oder Scheibenaufnahmen. Der im Rahmen des NanoXSpot-Projektes neu entwickelte NxS-Testkörper ist geeignet für den Bereich von 1 μm – 100 μm. Von 100 μm bis 10 mm können ASTM-Lochtestkörper verwendet werden, die bereits bei ASTM E 1165 beschrieben sind. Neu ist die Anwendung eines CT-Algorithmus zur Rekonstruktion der Brennflecke, um Lochblenden-basierte Brennfleckkameras, insbesondere im Bereich unter 100 μm, zu ersetzen. Ein neuer Normteil, EN 12543-6, wurde entworfen, um die Brennfleckmessung im Bereich 100 nm – 20 μm mit hoher Genauigkeit zu ermöglichen.
Verschiedene Strichgruppen-Testkörper kommen hier zum Einsatz. Das sind die JIMAPrüfkörper, ein neuer Hochkontrast-Strichgruppentestkörper von YXLON (HiCo) und der neu entwickelte Testkörper NxS. Diese werden vorgestellt. Die Messprozedur für Röhrenhersteller wird auf einer numerischen Fit-Prozedur basieren, die über einen Ringversuch im Projekt validiert wurde. Beide Normen benötigen numerische Auswertealgorithmen zur korrekten Anwendung, die als kommerzielle Software und Public Domain – Software verfügbar gemacht werden. Es wird über die zu erwartenden Standardprozeduren und die erforderliche Hardware zur Anwendung der Normen informiert.
T2 - DGZfP-Jahrestagung
CY - Kassel, Germany
DA - 23.05.2022
KW - Röntgenröhre
KW - Brennfleckmessung
KW - Normung
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561029
SP - 1
EP - 10
AN - OPUS4-56102
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, David
A1 - Jaenisch, Gerd-Rüdiger
A1 - Ewert, U.
A1 - Bircher, B.
A1 - Meli, F.
A1 - Sofiienko, A.
A1 - Steffen, J. P.
A1 - Deresch, A.
T1 - EMPIR-Projekt NanoXSpot: Ringversuch zur Untersuchung der neu entwickelten Methoden für die Brennfleckmessung an Röntgenröhren im Mikro- und Nanometerbereich
N2 - Im Rahmen des EMPIR-Projektes NanoXSpot (Nanometre X-Ray Focal Spot Measurement) werden rückführbare Messverfahren zur Bestimmung der Brennfleckgröße und -form von Röntgenröhren mit Submikrometerauflösung (100 nm – 20 μm) entwickelt, die die Grundlage für die Erarbeitung eines Standardentwurfes bilden. Der Standardentwurf wird bei CEN TC 138 (Non-destructive testing) WG 1 (Radiographic testing) eingereicht und mit ISO und ASTM harmonisiert. Zur Untersuchung der entwickelten Methoden (Brennfleck-CT, Fit-Prozedur für Strichgruppenkörper) und des im Projekt NanoXSpot neu entworfenen Testkörpers, NxS, wurde ein Ringversuch durchgeführt. Dabei wurde sowohl der angestrebte Überlappungsbereich mit EN 12543 Teil 5 (Messung der effektiven Brennfleckgröße von Mini- und Mikrofokus-Röntgenröhren) und ASTM E 2903 (Standard Test Method for Measurement of the Effective Focal Spot Size of Mini and Micro Focus X-ray Tubes) für Brennflecke >5 μm als auch Brennflecke <5 μm untersucht. Im Mittelpunkt standen dabei Stabilität und Wiederholbarkeit der entwickelten Methoden zur Bestimmung der Brennfleckgröße. In diesem Beitrag werden die Ergebnisse des durchgeführten Ringversuches vorgestellt und diskutiert, um Schlussfolgerungen und Empfehlungen für die Vorbereitung eines erweiterten Ringversuchs mit Partnern und Stakeholdern abzuleiten.
T2 - DGZfP-Jahrestagung
CY - Kassel, Germany
DA - 23.05.2022
KW - Brennfleckmessung
KW - Computer-Tomografie
KW - EMPIR
KW - Normung
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561037
SP - 1
EP - 2
AN - OPUS4-56103
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mueller, I.
A1 - Memmolo, V.
A1 - Tschöke, K.
A1 - Moix-Bonet, M.
A1 - Möllenhoff, K.
A1 - Golub, M.
A1 - Sridaran Venkat, R.
A1 - Lugovtsova, Yevgeniya
A1 - Eremin, A.
A1 - Moll, J.
T1 - Performance Assessment for a Guided Wave-Based SHM System Applied to a Stiffened Composite Structure
N2 - To assess the ability of structural health monitoring (SHM) systems, a variety of prerequisites and contributing factors have to be taken into account. Within this publication, this variety is analyzed for actively introduced guided wave-based SHM systems. For these systems, it is not possible to analyze their performance without taking into account their structure and their applied system parameters. Therefore, interdependencies of performance assessment are displayed in an SHM pyramid based on the structure and its monitoring requirements. Factors influencing the quality, capability and reliability of the monitoring system are given and put into relation with state-of-the-art performance analysis in a non-destructive evaluation. While some aspects are similar and can be treated in similar ways, others, such as location, environmental condition and structural dependency, demand novel solutions. Using an open-access data set from the Open Guided Waves platform, a detailed method description and analysis of path-based performance assessment is presented.The adopted approach clearly begs the question about the decision framework, as the threshold affects the reliability of the system. In addition, the findings show the effect of the propagation path according to the damage position. Indeed, the distance of damage directly affects the system performance. Otherwise, the propagation direction does not alter the potentiality of the detection approach despite the anisotropy of composites. Nonetheless, the finite waveguide makes it necessary to look at the whole paths, as singular phenomena associated with the reflections may appear. Numerical investigation helps to clarify the centrality of wave mechanics and the necessity to take sensor position into account as an influencing factor. Starting from the findings achieved, all the issues are discussed, and potential future steps are outlined.
KW - Reliability assessment
KW - Ultrasonic Guided Waves
KW - Structural Health Monitoring
KW - Probability of detection
KW - Path-based analysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558853
DO - https://doi.org/10.3390/s22197529
VL - 22
IS - 19
SP - 1
EP - 28
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55885
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazemifard, N.
A1 - Dehkohneh, Abolfazl
A1 - Baradaran Ghavami, S.
T1 - Probiotics and probiotic-based vaccines: A novel approach for improving vaccine efficacy
N2 - Vaccination is defined as the stimulation and development of the adaptive immune system by administering specific antigens. Vaccines' efficacy, in inducing immunity, varies in different societies due to economic, social, and biological conditions. One of the influential biological factors is gut microbiota. Cross-talks between gut bacteria and the host immune system are initiated at birth during microbial colonization and directly control the immune responses and protection against pathogen colonization. Imbalances in the gut microbiota composition, termed dysbiosis, can trigger several immune disorders through the activity of the adaptive immune system and impair the adequate response to the vaccination. The bacteria used in probiotics are often members of the gut microbiota, which have health benefits for the host. Probiotics are generally consumed as a component of fermented foods, affect both innate and acquired immune systems, and decrease infections. This review aimed to discuss the gut microbiota's role in regulating immune responses to vaccination and how probiotics can help induce immune responses against pathogens. Finally, probiotic-based oral vaccines and their efficacy have been discussed.
KW - Probiotics
KW - Gut microbiota
KW - Probiotic-based vaccines
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561767
DO - https://doi.org/10.3389/fmed.2022.940454
SN - 2296-858X
VL - 9
SP - 1
EP - 15
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-56176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ewert, U.
A1 - Jaenisch, Gerd-Rüdiger
A1 - Schumacher, David
A1 - Zscherpel, U.
A1 - Deresch, A.
A1 - Bircher, B.
A1 - Meli, F.
T1 - Schnelle Messung und tomographische Rekonstruktion von Brennflecken < 5 μm durch Aufnahmen strukturierter Prüfkörper
N2 - Im Europäischen EMPIR-Projekt „NanoXSpot“ (Measurement of the focal spot size of Xray tubes with spot sizes down to 100 nm) werden neue Messmethoden für Brennflecke von Röntgenröhren entwickelt. Teil des Projektes ist die Entwicklung eines zur Lochkameramethode äquivalenten Messverfahrens für kleine Brennflecke. ASTM E 1165-20, Annex A, beschreibt die Bestimmung von Brennfleckgrößen aus Kantenprofilen von Lochaufnahmen für Röntgenröhren mit Brennflecken > 50 μm. Es wurde bereits vorgeschlagen über die Analyse der richtungsabhängigen Kantenunschärfe einer Lochblende und anschließender CT-Rekonstruktion die Intensitätsverteilung des Brennflecks äquivalent zur Lochkameraaufnahme zu berechnen. Die Lochkameramethode, wie in EN 12543-2 und ASTM E 1165-20 beschrieben, ist im unteren Größenbereich für Mikrofokusröhren nicht geeignet, da Pinholes < 10 μm schwer zu fertigen sind und lange Belichtungszeiten erwartet werden. Mit Hilfe exakt gefertigter Lochblenden sowie strukturierter Targets mit
konvergierenden Strukturen wird der Bereich mit der Single-Shot-CT-Methode auf die Messung von Mikrofokusröhren, alternativ zur Vermessung von Kanten oder Strichgruppenkörpern, erweitert. Die rekonstruierten Brennfleckformen werden mit Kantenund Lochkameraaufnahmen quantitativ verglichen, um die Messgenauigkeit zu bewerten.
Außerdem werden CNR und Messzeit bestimmt, um die Wirtschaftlichkeit der Verfahren zu bewerten.
T2 - DGZfP-Jahrestagung
CY - Online meeting
DA - 10.05.2021
KW - Röntgenröhre
KW - Brennfleckmessung
KW - Prüfkörper
KW - Rekonstruktion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561846
SP - 1
EP - 2
AN - OPUS4-56184
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurster, S.
A1 - Ladu, Luana
T1 - Triple-C: A Tridimensional Sustainability-Oriented Indicator for Assessing Product Circularity in Public Procurement
N2 - Various microlevel circular economy indicators for assessing sustainability and, partly, additional sustainability characteristics have been developed, but an integrated solution considering the environmental, social, and economic pillars remains a research gap. Method: Based on a multimethod approach, including surveys and the analysis of existing sustainability assessment methodologies and standards, this paper proposes a concept for a multidimensional circular economy indicator tailored to public procurers. It relies on attractive existing building blocks including: the ecological scarcity method, European and international sustainability standards and indicators,and the STAR-ProBio-IAT concept. Results: This article presents the concept of the composite indicator Triple-C, consisting of 20 elements and aimed at facilitating sustainable circular public procurement. It is intended to be incorporated into software that facilitates sustainable product decisions among public procurers in Germany. Conclusions: We propose a generic indicator concept covering all three (environmental, social, and economic) sustainability pillars. More research and additional standards are needed to develop the Triple-C concept further into product-specific applications.
KW - Circular economy
KW - Sustainability assessment
KW - Circularity
KW - Ecological scarcity method
KW - Life-cycle assessment
KW - LCA
KW - Life-cycle costing
KW - LCC
KW - Social sustainability
KW - Indicators
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564115
DO - https://doi.org/10.3390/su142113936
VL - 14
IS - 21
SP - 1
EP - 23
PB - MDPI
CY - Berlin
AN - OPUS4-56411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heßmann, Jennifer
A1 - Hilgenberg, Kai
T1 - New approach for multi-material design: Combination of laser beam and electromagnetic melt pool displacement by induced Lorentz forces
N2 - Multimaterial structures are a promising solution to reduce vehicle weight and save fuel or electric energy in automotive design. However, thermal joining of steel and aluminum alloys is a challenge to overcome due to different material properties and the formation of brittle intermetallic phases. In this study, a new joining approach for producing overlap line-shaped joints is presented. The lower joining partner (EN AW 5754) is melted by a laser beam, and this melt is displaced into a line-shaped cavity of the upper joining partner (1.0330) by induced Lorentz forces. The melt solidifies in the cavity to a material and form-fitting joint. This approach needs no auxiliary joining elements or filler materials. Previous investigation to produce spot-shaped joints by using this approach showed that quality and reproducibility were limited by known melt pool dynamics of aluminum alloys (keyhole collapses). For line-shaped joints, the melt displacement can take place behind the keyhole. This allows the displacement process to be spatially uncoupled from the influence of keyhole collapses. The study shows that this improved the process stability and the quality of the joint. The created line-shaped joints were microstructurally characterized by transversal sections. Intermetallic phases were identified by electron backscatter diffraction and EDX analysis. The detected intermetallic phases consist of a 5–6 μm compact phase seam of Al5.6Fe2 and a needle-shaped phase of Al13Fe4. Tensile shear tests were carried out to quantify the load capacity. It was possible to create a joint with a load capacity of about 2 kN.
KW - Electromagnetic forces
KW - Joining dissimilar materials
KW - Laser beam welding
KW - Steel and aluminium
KW - Lorentz forces
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564840
DO - https://doi.org/10.2351/7.0000763
SN - 1042-346X
VL - 35
IS - 1
SP - 1
EP - 8
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-56484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Junge, P.
A1 - Greinacher, M.
A1 - Kober, D.
A1 - Stargardt, Patrick
A1 - Rupprecht, C.
T1 - Metastable Phase Formation, Microstructure, and Dielectric Properties in Plasma-Sprayed Alumina Ceramic Coatings
N2 - The need for new solutions for electrical insulation is growing due to the increased electrification in numerous industrial sectors, opening the door for innovation. Plasma spraying is a fast and efficient way to deposit various ceramics as electrical insulators, which are used in conditions where polymers are not suitable. Alumina (Al2O3) is among the most employed ceramics in the coating industry since it exhibits good dielectric properties, high hardness, and high melting point, while still being cost-effective. Various parameters (e.g., feedstock type, spray distance, plasma power) significantly influence the resulting coating in terms of microstructure, porosity, and metastable phase formation. Consequently, these parameters need to be investigated to estimate the impact on the dielectric properties of plasma-sprayed alumina coatings. In this work, alumina coatings with different spray distances have been prepared via atmospheric plasma spray (APS) on copper substrates. The microstructure, porosity, and corresponding phase formation have been analyzed with optical microscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Moreover, we present an in-depth analysis of the fundamental dielectric properties e.g., direct current (DC) resistance, breakdown strength, dielectric loss tangent, and permittivity. Our results show that decreasing spray distance reduces the resistivity from 6.31 × 109 Ωm (130 mm) to 6.33 × 108 Ωm (70 mm), while at the same time enhances the formation of the metastable δ-Al2O3 phase. Furthermore, space charge polarization is determined as the main polarization mechanism at low frequencies.
KW - Alumina
KW - Plasma spray
KW - Dielectric properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564394
DO - https://doi.org/10.3390/coatings12121847
SN - 2079-6412
VL - 12
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-56439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nasr Esfahani, M.
A1 - Zare Pakzad, S.
A1 - Li, T.
A1 - Li, X.
A1 - Tasdemir, Z.
A1 - Wollschläger, Nicole
A1 - Leblebici, Y.
A1 - Erdem Alaca, B.
T1 - Effect of Native Oxide on Stress in Silicon Nanowires: Implications for Nanoelectromechanical Systems
N2 - Understanding the origins of intrinsic stress in Si nanowires (NWs) is crucial for their successful utilization as transducer building blocks in next-generation, miniaturized sensors based on anoelectromechanical systems (NEMS). With their small size leading to ultrahigh-resonance frequencies and extreme surface-to-volume ratios, silicon NWs raise new opportunities regarding sensitivity, precision, and speed in both physical and biochemical sensing. With silicon optoelectromechanical properties strongly dependent on the level of NW intrinsic stress, various studies have been devoted to the measurement of such stresses generated, for example, as a result of harsh fabrication processes. However, due to enormous NW surface area, even the native oxide that is conventionally considered as a benign surface condition can cause significant stresses. To address this issue, a combination of nanomechanical characterization and atomistic simulation approaches is developed. Relying only on low-temperature processes, the fabrication approach yields monolithic NWs with optimum boundary conditions, where NWs and support architecture are etched within the same silicon crystal. Resulting NWs are characterized by transmission electron microscopy and micro-Raman spectroscopy. The interpretation of results is carried out through molecular dynamics simulations with ReaxFF potential facilitating the incorporation of humidity and temperature, thereby providing a close replica of the actual oxidation environment - in contrast to previous dry oxidation or self-limiting thermal oxidation studies. As a result, consensus on significant intrinsic tensile stresses on the order of 100 MPa to 1 GPa was achieved as a function of NW critical dimension and aspect ratio. The understanding developed herein regarding the role of native oxide played in the generation of NW intrinsic stresses is important for the design and development of silicon-based NEMS.
KW - Nanoelectromechanical systems (NEMS)
KW - Silicon nanowires
KW - Native oxide
KW - Intrinsic stress
KW - Raman spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560471
DO - https://doi.org/10.1021/acsanm.2c02983
SN - 2574-0970
VL - 5
SP - 13276
EP - 13285
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zabihi, Mohammadmasoud
A1 - Krebber, Katerina
T1 - Approach for Faster Signal Processing in Փ-OTDR Systems Based on Directional Measurement of Fiber Slices Interaction
N2 - In this study, a signal processing approach for heterodyne Փ-OTDR and C-OTDR systems that can obtain external perturbation and its frequency content in a faster way is proposed. We can detect vibrations with the same or better SNR using this processing approach, only with a single step and fast calculation. Fig. 12 shows the comparison of the normalized measurement time for the gamma matrix method and the conventional method throughout the three experiments. The speed of processing using a gamma matrix is ~35%–50% faster compared to a conventional method in high frequency test (PZT), low frequency test (walking) and street monitoring test. The processing speed in low frequency test is normally a bit lower than the similar high frequency one, since we must use higher number of time frames. Also, in street test we have higher speed because we can select wider gauges.
KW - Փ-OTDR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560492
DO - https://doi.org/10.1364/OPTCON.456421
VL - 1
IS - 8
SP - 1837
EP - 1847
PB - Optica Publishing Group
CY - Washington, DC
AN - OPUS4-56049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zabihi, Mohammadmasoud
A1 - Krebber, Katerina
T1 - Laser source frequency drift compensation in Φ-OTDR systems using multiple probe frequencies
N2 - In this study, an approach for mitigation of LSFD in Φ-OTDR systems was proposed. By using one probe pulse as a reference in a system with two or more probe frequencies, we can remove unwanted low frequency noise that is originally caused by the laser source. Although LSFD is problematic issue, it is not the only source of low frequency noise. Change in temperature, humidity, physical surroundings, environment, etc., can result in such noises. The proposed method; however, is expected to highly suppresses all of these effects, regardless of their source, either in the time or frequency domain.
For comparing reference and probe signals, there are sophisticated methods, rather than normal differentiation, available for use. Some of these methods have a close relationship with CPD methods and can further enhance the results. These methods can be further discussed in an independent research or future work.
The proposed method is very helpful for increasing accuracy in passive and active seismic monitoring, reservoir monitoring, underwater monitoring, etc. It also helps using relatively simpler laser sources and make the whole system price-efficient, as well as processing data without lengthy compensation algorithms.
KW - Frequency Drift
KW - Փ-OTDR
KW - LSFD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560517
DO - https://doi.org/10.1364/oe.460302
SN - 1094-4087
VL - 30
IS - 11
SP - 19990
EP - 19998
PB - Optica
CY - Washington, DC
AN - OPUS4-56051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steinhäuser, Lorin
A1 - Piechotta, Christian
A1 - Westphalen, Tanja
A1 - Kaminski, Katja
T1 - Evaluation, comparison and combination of molecularly imprinted polymer solid phase extraction and classical solid phase extraction for the preconcentration of endocrine disrupting chemicals from representative whole water samples
N2 - Estrogens are endocrine disrupting chemicals and of high concerns due to demonstrated harmful effects on the environment and low effect levels. For monitoring and risk assessment, several estrogens were included in the "watch list" of the EU Water Framework Directive which sets very low environmental quality standard (EQS) levels for Estrone (E1) and 17β-Estradiol (E2) of 0.4 ng L−1 and for 17α-Ethinylestradiol (EE2) of 0.035 ng L−1 requiring sensitive detection methods, as well as extensive sample preparation. A sensitive, derivatization-free, isotope dilution calibration HPLC-MS/MS method for a panel of 5 selected estrogens (including the 3 estrogens of the EU WFD watchlist), and a procedure for the reproducible preparation of a representative whole water matrix including mineral water, humic acids and solid particulate matter are presented. These are used in a diligent comparison of classical solid phase extraction (SPE) on hydrophilic-lipophilic balanced (HLB) phase to SPE on an estrogen-specific molecularly imprinted polymer phase (MISPE) for ultra-trace levels of the analytes (1–10 ng L−1). Additionally, a two-step procedure combining HLB SPE disks followed by MISPE is evaluated. The tow-step procedure provides superior enrichment, matrix removal and sample throughput while maintaining comparable recovery rates to simple cartridge SPE. Estimated method quantification limits (MQLs) range from 0.109–0.184 ng L−1 and thus meet EQS-levels for E1 and E2, but not EE2. The representative whole water matrix provides a reproducible comparison of sample preparation methods and lays the foundation for a certified reference material for estrogen analysis. The presented method will serve as the basis for an extended validation study to assess its use for estrogen monitoring in the environment.
KW - Estrogens
KW - Whole water samples
KW - Molecular imprinted polymers
KW - EU-WFD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563547
DO - https://doi.org/10.1016/j.talo.2022.100163
SN - 2666-8319
VL - 6
SP - 1
EP - 5
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-56354
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ehlers, Henrik
A1 - Thewes, R.
A1 - Pelkner, Matthias
T1 - Online Process Monitoring for Additive Manufacturing Using Eddy Current Testing With Magnetoresistive Sensor Arrays
N2 - The rising popularity of additive manufacturing processes leads to an increased interest in possibilities and methods for related process monitoring. Such methods ensure improved process quality and increase the understanding of the manufacturing process, which in turn is the basis for stable component quality, e.g., required in the aerospace industry or in the medical sector. For laser powder bed fusion, a handful of process monitoring tools already exist, such as optical tomography, thermography, pyrometry, imaging, or laser power monitoring. Although these tools provide helpful information about the process, more information is required for an accurate in-depth understanding. In this article, advanced approaches in eddy current testing (ET) are combined, such as single wire excitation, magnetoresistive (MR) sensor arrays, and heterodyning to build up a system that can be used for online process monitoring of laser powder bed fusion. In addition to detailed information about the developed ET system and underlying signal processing, the first results of magnetoresistance-basedonline ET during the laser powder fusion process are presented. While producing a step-shaped cuboid, each layer is tested during recoating.
Test results show that not only the contours of the topmost layer are detected but also the contours of previous layers covered by powder. At an excitation frequency of 1 MHz, a penetration depth of approx. 400 μm is obtained. To highlight the possibilities of ET for online process monitoring of laser powder bed fusion, results are compared with postexposure images of the integrated layer control system (LCS).
KW - Process monitoring
KW - Eddy current testing
KW - Giant magneto resistance (GMR)
KW - Additive manufacturing
KW - Laser powder bed fusion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560881
DO - https://doi.org/10.1109/JSEN.2022.3205177
VL - 22
IS - 20
SP - 19293
EP - 19300
PB - IEEE
CY - New York, NY
AN - OPUS4-56088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiehle, Philipp
A1 - Brinkmann, M.
T1 - Material behaviour of unstabilised earth block masonry and its components under compression at varying relative humidity
N2 - block and mortar types is analysed with particular regard to the influence of varying relative humidity. The uniaxial compressive strength and deformation characteristics of unstabilised earth blocks and mortars as well as of unstabilised earth block masonry are studied in detail and compared to conventional masonry to evaluate whether the structural design can be made accordingly. An increase of 30 % points in relative humidity leads to a reduction of the masonry´s compressive strength between 33 % and 35 % whereas the Young´s modulus is reduced by 24–29 %. However, the ratio between the Young´s modulus and the characteristic compressive strength of earth block masonry ranges between E33/fk = 283–583 but is largely independent of the relative humidity. The results show that the mechanical properties of the investigated unstabilised earth block masonry are sufficient for load-bearing structures, yielding a masonry compressive strength between 2.3 MPa and 3.7 MPa throughout the range of moisture contents
investigated. In general, the design concept of conventional masonry can be adapted for unstabilised earth masonry provided that the rather low Young´s modulus as well as the moisture dependence of both, compressive strength and Young´s modulus, are sufficiently taken into
account.
KW - Compressive strength
KW - Earth block masonry
KW - Compression tests
KW - Stress-strain relation
KW - Relative humidity
KW - Moisture content
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562417
DO - https://doi.org/10.1016/j.cscm.2022.e01663
SN - 2214-5095
VL - 17
SP - 1
EP - 15
PB - Elsevier B.V.
CY - Netherlands
AN - OPUS4-56241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hong, H.
A1 - Part, Florian
A1 - Nowack, B.
T1 - Prospective dynamic and probabilistic material flow analysis of graphene-based materials in Europe from 2004 to 2030
N2 - As industrial demand for graphene-based materials (GBMs) grows, more attention falls on potential environmental risks. The present article describes a first assessment of the environmental releases of GBMs using dynamic probabilistic material flow analysis. The model considered all current or expected uses of GBMs from 2004 to 2030, during which time there have already been significant changes in how the graphene mass produced is distributed to different product categories. Although the volume of GBM production is expected to grow exponentially in the coming years, outflow from the consumption of products containing GBMs shows only a slightly positive trend due to their long lifetimes and the large in-use stock of some applications (e.g., GBM composites used in wind turbine blades). From consumption and end-of-life phase GBM mass flows in 2030, estimates suggest that more than 50% will be incinerated and oxidized in waste plants, 16% will be landfilled, 12% will be exported out of Europe, and 1.4% of the annual production will flow to the environment. Predicted release concentrations for 2030 are 1.4 ng/L in surface water and 20 μg/kg in sludge-treated soil. This study’s results could be used for prospective environmental risk assessments and as input for environmental fate models.
KW - Graphene
KW - Graphene-based material (GBM)
KW - Material flow analysis
KW - Exposure modeling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568843
DO - https://doi.org/10.1021/acs.est.2c04002
SN - 0013-936X
SN - 1520-5851
VL - 56
SP - 13798
EP - 13809
PB - American Chemical Society
CY - Columbus, Ohio
AN - OPUS4-56884
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tatzel, M.
A1 - Frings, P. J.
A1 - Oelze, Marcus
A1 - Herwartz, D.
A1 - Lünsdorf, K.
A1 - Wiedenbeck, M.
T1 - Chert oxygen isotope ratios are driven by Earth's thermal evolution
N2 - The 18O/16O ratio of cherts (δ18Ochert) increases nearly monotonically by ~15‰ from the Archean to present. Two end-member explanations have emerged: cooling seawater temperature (TSW) and increasing seawater δ18O (δ18Osw). Yet despite decades of work, there is no consensus, leading some to view the δ18Ochert record as pervasively altered.
Here, we demonstrate that cherts are a robust archive of diagenetic temperatures, despite metamorphism and exposure to meteoric fluids, and show that the timing and temperature of quartz precipitation and thus δ18Ochert are determined by the kinetics of silica diagenesis. A diagenetic model shows that δ18Ochert is influenced by heat flow through the sediment column. Heat flow has decreased over time as planetary heat is dissipated, and reasonable Archean-modern heat flow changes account for ~5‰ of the increase in δ18Ochert, obviating the need for extreme TSW or δ18Osw reconstructions. The seawater oxygen isotope budget is also influenced by solid Earth cooling, with a recent reconstruction placing Archean δ18OSW 5 to 10‰ lower than today. Together, this provides an internally consistent view of the δ18Ochert record as driven by solid Earth cooling over billion-year timescales that is compatible with Precambrian glaciations and biological.
KW - Climate
KW - Oxygen isotope ratios
KW - Silica diagenesis
KW - Early Earth
KW - Heat flow
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569359
DO - https://doi.org/10.1073/pnas.2213076119
SN - 0027-8424
VL - 119
IS - 51
SP - 1
EP - 7
PB - National Academy of Sciences
CY - Washington, DC
AN - OPUS4-56935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merz, Benjamin
A1 - Nilsson, R.
A1 - Garske, C.
A1 - Hilgenberg, Kai
T1 - Camera-based high precision position detection for hybrid additive manufacturing with laser powder bed fusion
N2 - Additive manufacturing (AM) in general and laser powder bed fusion (PBF-LB/M) in particular are becoming increasingly important in the field of production technologies. Especially the high achievable accuracies and the great freedom in design make PBF-LB/M interesting for the manufacturing and repair of gas turbine blades. Part repair involves building AM-geometries onto an existing component. To minimise the offset between component and AM-geometry, a precise knowledge of the position of the component in the PBF-LB/M machine is mandatory. However, components cannot be inserted into the PBF-LB/M machine with repeatable accuracy, so the actual position will differ for each part. For an offset-free build-up, the actual position of the component in the PBF-LB/M machine has to be determined. In this paper, a camera-based position detection system is developed considering PBF-LB/M constraints and system requirements. This includes finding an optimal camera position considering the spatial limitations of the PBF-LB/M machine and analysing the resulting process coordinate systems. In addition, a workflow is developed to align different coordinate systems and simultaneously correct the perspective distortion in the acquired camera images. Thus, position characteristics can be determined from images by image moments. For this purpose, different image segmentation algorithms are compared. The precision of the system developed is evaluated in tests with 2D objects. A precision of up to 30μm in translational direction and an angular precision of 0.021∘ is achieved. Finally, a 3D demonstrator was built using this proposed hybrid strategy. The offset between base component and AM-geometry is determined by 3D scanning and is 69μm.
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Hybrid repair
KW - Machine vision
KW - Image processing
KW - Position detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568583
DO - https://doi.org/10.1007/s00170-022-10691-5
SP - 1
EP - 16
PB - Springer
AN - OPUS4-56858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breuninger, Esther S.
A1 - Tolu, Julie
A1 - Aemisegger, Franziska
A1 - Thurnherr, Iris
A1 - Bouchet, Sylvain
A1 - Mestrot, Adrien
A1 - Ossola, Rachele
A1 - McNeill, Kristopher
A1 - Tukhmetova, Dariya
A1 - Vogl, Jochen
A1 - Meermann, Björn
A1 - Sonke, Jeroen E.
A1 - Winkel, Lenny H. E.
T1 - Marine and terrestrial contributions to atmospheric deposition fluxes of methylated arsenic species
N2 - Arsenic, a toxic element from both anthropogenic and natural sources, reaches surface environments through atmospheric cycling and dry and wet deposition. Biomethylation volatilizes arsenic into the atmosphere and deposition cycles it back to the surface, affecting soil-plant systems. Chemical speciation of deposited arsenic is important for understanding further processing in soils and bioavailability. However, the range of atmospheric transport and source signature of arsenic species remain understudied. Here we report significant levels ofmethylated arsenic in precipitation, cloudwater and aerosols collected under free tropospheric conditions at Pic du Midi Observatory (France) indicating long-range transport, which is crucial for atmospheric budgets. Through chemical analyses andmoisture source diagnostics, we identify terrestrial and marine sources for distinct arsenic species. Estimated atmospheric deposition fluxes of methylated arsenic are similar to reported methylation rates in soils, highlighting atmospheric deposition as a significant, overlooked source of potentially bioavailable methylated arsenic
species impacting plant uptake in soils.
KW - Arsenic
KW - Speciation
KW - Fluxes
KW - Marine
KW - Terrestrial
KW - Sulfur isotopes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615551
DO - https://doi.org/10.1038/s41467-024-53974-z
SN - 2041-1723
VL - 15
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-61555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yagdjian, H.
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Ziegler, Mathias
A1 - Gurka, M.
T1 - Application of the thermal shock response spectrum (TSRS) methodology to various forms of heat sources by pulse thermography and comparison by using a rotating line scan contour search algorithm
N2 - In this paper, we propose a novel contour search algorithm (CSA) for image processing. Its efficacy is evaluated through a comparative analysis with established techniques such as Canny Edge and Snakes: Active contour models, utilizing infrared thermography (IRT) images. Based on the new CSA, we investigate the influence of different pulse shapes on the IRT post-processing methodology, particularly focusing on the thermal shock response spectrum (TSRS), using two different heat sources: xenon flash lamps and a laser. Moreover, this allows for a more precise quantitative comparison of the TSRS with existing IRT post-processing techniques, including pulse phase thermography and thermal signal reconstruction, concerning the detection of defects in composite materials, particularly in carbon fiber-reinforced polymer. A quantitative comparison was performed using the Tanimoto criterion and signal-to-noise ratio. A more detailed analysis is conducted to identify inherent limitations and potential benefits of the new TSRS methodology. We further investigate and experimentally confirm our previous finding on the qualitative correlation between the one-dimensional thermal N-layer model and test data from the TSRS optimization process for defect determination. This correlation can eliminate the time-consuming optimization step, making TSRS a more attractive alternative to common IRT methods and enhancing the quantitative description of defects.
KW - Thermography
KW - Non-destructive testing
KW - NDT
KW - Defect identification
KW - Laser
KW - Contour search
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615056
DO - https://doi.org/10.1063/5.0232015
SN - 1089-7550
VL - 136
IS - 175101
SP - 1
EP - 20
PB - AIP Publishing
AN - OPUS4-61505
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abed, Jehad
A1 - Bai, Yanh
A1 - Persaud, Daniel
A1 - Kim, Jiheon
A1 - Witt, Julia
A1 - Hattrick.Simpers, Jason
A1 - Sargent, Edward
T1 - AMPERE: automated modular platform for expedited and reproducible electrochemical testing
N2 - Rapid and reliable electrochemical screening is critical to accelerate the development of catalysts for sustainable energy generation and storage. This paper introduces an automated and modular platform for expedited and reproducible electrochemical testing (AMPERE), designed to enhance the efficiency and reliability of multivariate optimization. The platform integrates a liquid-handling robot with custommade modular array reactors, offering sample preparation and electrochemical testing in the same platform. Additionally, we use offline inductively coupled plasma optical emission spectroscopy (ICPOES) to measure metal concentrations in the electrolyte after the reaction, which serves as a proxy for assessing the electrochemical stability. We use the platform to conduct 168 experiments continuously in less than 40 hours to examine the influence of catalyst ink formulation on the performance of Ir, Ru, IrO2, and RuO2 for the oxygen evolution reaction (OER) in acid. We specifically investigate the role of solvent type and concentration, catalyst concentration, and binder content on the performance. We find that Ru/RuO2 catalysts show improvements in activity that are not directly linked to improvements in the electrochemical surface area or inversely correlated to Ru dissolution. This suggests a complex interplay between the catalytic performance of the drop-casted catalyst film and ink formulation. AMPERE simplifies catalyst preparation and testing at large scale, making it faster, more reliable, and accessible for
widespread use.
KW - Electrochemical screening
KW - Automated platform
KW - Catalysis
KW - Energy generation and storage
KW - Oxygen evolution reaction (OER)
KW - MAPz@BAM
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614724
DO - https://doi.org/10.1039/d4dd00203b
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudhuri, Somsubhro
A1 - Stamm, Michael
A1 - Lapšanská, Ivana
A1 - Lançon, Thibault
A1 - Osterbrink, Lars
A1 - Driebe, Thomas
A1 - Hein, Daniel
A1 - Harendt, René
T1 - Infrared Thermography of Turbulence Patterns of Operational Wind Turbine Rotor Blades Supported With High‐Resolution Photography: KI‐VISIR Dataset
N2 - With increasing wind energy capacity and installation of wind turbines, new inspection techniques are being explored to examine wind turbine rotor blades, especially during operation. A common result of surface damage phenomena (such as leading edge erosion) is the premature transition of laminar to turbulent flow on the surface of rotor blades. In the KI-VISIR (Künstliche Intelligenz Visuell und Infrarot Thermografie—Artificial Intelligence-Visual and Infrared Thermography) project, infrared thermography is used as an inspection tool to capture so-called thermal turbulence patterns (TTPs) that result from such surface contamination or damage. To complement the thermographic inspections, high-resolution photography is performed to visualise, in detail, the sites where these turbulence patterns initiate. A convolutional neural network (CNN) was developed and used to detect and localise turbulence patterns. A unique dataset combining the thermograms and visual images of operational wind turbine rotor blades has been provided, along with the simplified annotations for the turbulence patterns. Additional tools are available to allow users to use the data requiring only basic Python programming skills.
KW - Thermography
KW - Thermografie
KW - Wind energy
KW - Leading edge erosion
KW - KI
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615772
DO - https://doi.org/10.1002/we.2958
IS - e2958
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-61577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vo, P. H.N.
A1 - Vogel, Christian
A1 - Nguyen, H. T.M.
A1 - Hamilton, B. R.
A1 - Thai, P. K.
A1 - Roesch, Philipp
A1 - Simon, Franz-Georg
A1 - Mueller, J. F.
T1 - µ-X-ray fluorescence (XRF) and fluorine K-edge µ-X-ray absorption near-edge structure (XANES) spectroscopy for detection of PFAS distribution in the impacted concrete
N2 - An improved understanding of the distribution of per- and polyfluoroalkyl substances (PFAS) in PFAS-impacted concrete is important for risk management and decontamination of PFAS. This study incorporates µ-X-ray fluorescence (µ-XRF) and fluorine K-edge µ-X-ray absorption near-edge structure (µ-XANES) spectroscopy to gain non-destructive insights into PFAS distribution in the impacted concrete. The μ-XRF and μ-XANES spectroscopy provided additional details on the detection of PFAS, which were not detected by the desorption electrospray ionization (DESI) imaging method conducted previously. The shorter chain PFAS were found on the top part of the concrete core (0.5 cm), and longer chain PFAS were mostly at the bottom part of the concrete core (5 cm). The inorganic fluorine fraction was also detected, and it likely hampered the detection of organic fluorine such as PFAS in the concrete. Thus, this non-destructive technique is an complementary approach to detect PFAS in contaminated concrete.
KW - Beton
KW - Per- and Polyfluoroalkyl substances (PFAS)
KW - XANES spectroscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616711
DO - https://doi.org/10.1016/j.hazl.2024.100134
SN - 2666-9110
VL - 5
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-61671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Krebber, Katerina
T1 - Suppression of Rayleigh fading induced errors in φOTDR by different pulse widths for improving the reliability of civil infrastructure monitoring
N2 - Rayleigh fading is a widely observed phenomenon in the many fields, such as wireless communication and optical imaging. It is also the main factor limiting the performance of the phase-sensitive optical time domain reflectometry (φOTDR). The low SNR at the fading points results in a large measurement error, severely affecting the reliability of civil infrastructure monitoring. The proposed method involves changing the pulse width during measurements to suppress the impact of fading. Experimental result shows that the number of fading points is greatly reduced by ∼ 96 % and the measurement error is reduced by more than 5 times. Unlike existing methods, this approach requires no hardware modifications, making it applicable to almost all current phase-based φOTDR systems. The versatility and effectiveness of this method make it an excellent candidate for infrastructure monitoring and related fields.
KW - Distributed fiber sensing
KW - Optical fiber sensing
KW - Phase-sensitive optical time domain reflectometry
KW - Infrastructure monitoring
KW - Rayleigh fading
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614208
DO - https://doi.org/10.1016/j.optlastec.2024.111927
SN - 1879-2545
VL - 181
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-61420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zweigle, J.
A1 - Schmidt, A.
A1 - Bugsel, B.
A1 - Vogel, Christian
A1 - Simon, Fabian
A1 - Zwiener, C.
T1 - Perfluoroalkyl acid precursor or weakly fluorinated organic compound? A proof of concept for oxidative fractionation of PFAS and organofluorines
N2 - Organofluorine mass balance approaches are increasingly applied to investigate the occurrence of per- and polyfluoroalkyl substances (PFAS) and other organofluorines in environmental samples more comprehensively. Usually, complex samples prevent the identification and quantification of every fluorine-containing molecule. Consequently, large unidentified fractions between fluorine sum parameters such as extractable organic fluorine (EOF) and the sum of quantified analytes are frequently reported. We propose using oxidative conversion to separate (unidentified) weakly fluorinated compounds (e.g., pesticides, pharmaceuticals) from PFAA-precursors (perfluoroalkyl chain lengths ≥ C6). We show with three organofluorine model substances (flufenamic acid, diflufenican, pantoprazole) that CF3-groups or aromatic fluorine can be quantitatively converted to inorganic fluoride and trifluoroacetic acid (TFA) by applying PhotoTOP oxidation (UV/TiO2). The principle of fluorine separation in mixtures is demonstrated by the oxidation of the three weakly fluorinated compounds together with the PFAA-precursor 6:2/6:2 fluorotelomer mercaptoalkyl phosphate diester (FTMAP). After oxidation, the products F− and TFA were separated from PFCAs ( C4) by SPE, and the fractions were analyzed individually. Closed mass balances both with and without the addition of organic matrix were achieved. Eventually, the fluorine balance was verified by total fluorine measurements with combustion ion chromatography (CIC). The proposed methods should be considered a proof of concept to potentially explain unidentified fractions of the EOF, especially if compounds with low fluorine content such as pesticides, pharmaceuticals, and their transformation products contribute largely to the EOF. Future studies are needed to show the applicability to the complexity of environmental samples.
Graphical Abstract
KW - Combustion Ion Chromatography
KW - Per- and Polyfluoroalkyl substances (PFAS)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613429
DO - https://doi.org/10.1007/s00216-024-05590-5
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-61342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yagdjian, H.
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Gurka, M.
T1 - Optimization of thermal shock response spectrum as infrared thermography post-processing methodology using Latin hypercube sampling and analytical thermal N-layer model
N2 - In this work, we continue to develop and investigate the Thermal Shock Response Spectrum (TSRS) method as an alternative data processing method for infrared thermography (IRT). We focus on improving the current TSRS algorithm and present an optimization methodology for finding the optimal thermal Q-factor and characteristic frequency pair, which is based on the widely applied random sampling method. We show the qualitative relationship between the determined optimal characteristic frequency and the corresponding maximum difference in diffusion length between reference and defective models, as calculated by selecting a specific one-dimensional thermal N-layer model. The investigations were performed on an inhomogeneous plate made of carbon fiber reinforced polymer (CFRP) with artificial square defects at different depths. Furthermore, two different heat sources were used: a xenon flash lamp and a laser. These sources are not only distinct by their underlying physics but also generate inherently different pulse shapes. To quantitatively estimate the contrast between defect and non-defect areas, and to compare these results with commonly used infrared thermography (IRT) data postprocessing methods such as Pulse Phase Thermography (PPT) and Thermographic Signal Reconstruction (TSR), the Tanimoto criterion (TC) and signal-to-noise ratio (SNR) were used.
KW - infrared thermography
KW - Composite materials
KW - TSRS optimization
KW - Defect identification
KW - Heat source shape
KW - N-layers model
KW - Latin Hypercube Sampling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614283
DO - https://doi.org/10.1016/j.infrared.2024.105582
SN - 1350-4495
VL - 143
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-61428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bianchi, M.
A1 - Cascavilla, A.
A1 - Clavell Diaz, J.
A1 - Ladu, Luana
A1 - Palacino Blazquez, Barbara
A1 - Menger, Pierre
A1 - Staffieri, Eleonora
A1 - Yilan, Gülsah Yilan
T1 - Circular bioeconomy: A review of empirical practices across implementation scales
N2 - The European Commission has endorsed the transition to a circular bioeconomy as a crucial initiative to achieve a sustainable and climate-neutral European Union. However, this transition is inherently complex, as it involves environmental and social risks, physical limitations, and trade-offs between different dimensions of sustainability. In this context, effective monitoring and modelling of the bioeconomy are essential tools to inform decision-making at various implementation scales. This article reviews empirical research on the monitoring and modelling of the bioeconomy and their implications for decision-making across three main implementation scales: macro (national-global level); meso (regional-city level); and micro (single product, company level). The contribution of this research is twofold: First, it explores existing gaps in the field through the lens of policy implementation levels. Research gaps include the uneven distribution of indicators among sustainability pillars, the lack of standardised monitoring frameworks at the meso and micro levels, and attribution issues in bioeconomy modelling. Second, the article outlines a comprehensive research agenda, indicating specific research lines and their relevance to different implementation scales. Key research avenues, significant at all implementation scales, include enhancing the life cycle perspective, visualising trade-offs and synergies between Sustainable Development Goals, monetising externalities, and further delving into social aspects.
KW - Bioeconomy
KW - Circular Economy
KW - Sustainable Transition
KW - Bioeconomy Monitoring Framework
KW - Bioeconomy Indicators
KW - Life cycle management
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612357
DO - https://doi.org/10.1016/j.jclepro.2024.143816
VL - 477
SP - 1
EP - 16
PB - Elsevier
AN - OPUS4-61235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - D'Agostino, Giancarlo
A1 - Oelze, Marcus
A1 - Vogl, Jochen
A1 - Ghestem, Jean-Philippe
A1 - Lafaurie, Nicolas
A1 - Klein, Ole
A1 - Pröfrock, Daniel
A1 - Di Luzio, Marco
A1 - Bergamaschi, Luigi
A1 - Jaćimović, Radojko
A1 - Oster, Caroline
A1 - Irrgeher, Johanna
A1 - Lancaster, Shaun T.
A1 - Walch, Anna
A1 - Röthke, Anita
A1 - Michaliszyn, Lena
A1 - Pramann, Axel
A1 - Rienitz, Olaf
A1 - Sara-Aho, Timo
A1 - Cankur, Oktay
A1 - Kutan, Derya
A1 - Noireaux, Johanna
T1 - Development and application of reference and routine analytical methods providing SI-traceable results for the determination of technology-critical elements in PCB from WEEE
N2 - The recovery and reprocessing of technology-critical elements (TCE) present in printed circuit boards (PCB) from electrical and electronic waste is essential both for recycling valuable materials subject to supply risk and for reducing the environmental impact. Although the quantitative knowledge of TCE amounts in endof- life PCB plays a key role, there are neither matrix certified reference materials nor harmonized analytical methods available to establish the traceability of the results to the International System of Units. To fill these gaps, we developed and applied five reference analytical methods based on ICP-MS standard addition calibrations and INAA k0- and relative calibrations suitable to certify reference materials. In addition, we developed and tested six analytical methods based on more commonly used ICP-MS external standard calibrations to provide industry with routine analysis methods. Twenty TCE (Ag, Au, Co, Cu, Dy, Ga, Gd, Ge, In, La, Li, Nd, Ni, Pd, Pr, Pt, Rh, Sm, Ta and Ti) were selected as target analytes and a batch of powdered PCB was used as measurement material. An overall mutual agreement was observed among data collected by reference methods at a few percent relative uncertainty levels. Moreover, all but one of the methods developed for routine analysis demonstrated their suitability in industrial applications by producing data within ± 20% of the values established with reference methods.
KW - Technology critical elements
KW - Electronic waste
KW - Printed circuit boards
KW - Traceability
KW - Uncertainty
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612416
DO - https://doi.org/10.1039/d4ja00235k
SN - 1364-5544
VL - 39
IS - 11
SP - 2809
EP - 2823
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lancaster, Shaun T.
A1 - Sahlin, Eskil
A1 - Oelze, Marcus
A1 - Ostermann, Markus
A1 - Vogl, Jochen
A1 - Laperche, Valérie
A1 - Touze, Solène
A1 - Ghestem, Jean-Philippe
A1 - Dalencourt, Claire
A1 - Gendre, Régine
A1 - Stammeier, Jessica
A1 - Klein, Ole
A1 - Pröfrock, Daniel
A1 - Košarac, Gala
A1 - Jotanovic, Aida
A1 - Bergamaschi, Luigi
A1 - Di Luzio, Marco
A1 - D’Agostino, Giancarlo
A1 - Jaćimović, Radojko
A1 - Eberhard, Melissa
A1 - Feiner, Laura
A1 - Trimmel, Simone
A1 - Rachetti, Alessandra
A1 - Sara-Aho, Timo
A1 - Roethke, Anita
A1 - Michaliszyn, Lena
A1 - Pramann, Axel
A1 - Rienitz, Olaf
A1 - Irrgeher, Johanna
T1 - Evaluation of X-ray fluorescence for analysing critical elements in three electronic waste matrices: A comprehensive comparison of analytical techniques
N2 - As the drive towards recycling electronic waste increases, demand for rapid and reliable analytical methodology to analyse the metal content of the waste is increasing, e.g. to assess the value of the waste and to decide the correct recycling routes. Here, we comprehensively assess the suitability of different x-ray fluorescence spectroscopy (XRF)-based techniques as rapid analytical tools for the determination of critical raw materials, such as Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd and Au, in three electronic waste matrices: printed circuit boards (PCB), light emitting diodes (LED), and lithium (Li)-ion batteries. As validated reference methods and materials to establish metrological traceability are lacking, several laboratories measured test samples of each matrix using XRF as well as other independent complementary techniques (instrumental neutron activation analysis (INAA), inductively coupled plasma mass spectrometry (ICP-MS) and ICP optical emission spectrometry (OES)) as an inter-laboratory comparison (ILC). Results highlighted key aspects of sample preparation, limits of detection, and spectral interferences that affect the reliability of XRF, while additionally highlighting that XRF can provide more reliable data for certain elements compared to digestion-based approaches followed by ICP-MS analysis (e.g. group 4 and 5 metals). A clear distinction was observed in data processing methodologies for wavelength
dispersive XRF, highlighting that considering the metals present as elements (rather than oxides) induces overestimations of the mass fractions when compared to other techniques. Eventually, the effect of sample particle size was studied and indicated that smaller particle size (<200 μm) is essential for reliable determinations.
KW - XRF
KW - WEEE
KW - PCB
KW - Battery
KW - LED
KW - Recycling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614060
DO - https://doi.org/10.1016/j.wasman.2024.10.015
VL - 190
SP - 496
EP - 505
PB - Elsevier B.V.
AN - OPUS4-61406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lengas, Nikolaos
A1 - Müller, Karsten
A1 - Schlick‐Hasper, Eva
A1 - Neitsch, Marcel
A1 - Johann, Sergej
A1 - Zehn, Manfred W.
T1 - Drop Test Simulation of Packaging for Dangerous Goods: An Investigation of Appropriate Drop Height Adjustment in Case of Deviating Packaging Gross Mass
N2 - In the approval process of dangerous goods packagings, drop tests onto a flat, essentially unyielding surface are used to assess resistance against mechanical damage. International adopted regulations like ADR and RID define filling good dependent drop heights and filling degrees whilst the user needs to define the maximum gross mass to be tested and approved. Maximum packaging gross mass is defined conservatively and not reached in practice. To meet the defined gross mass in testing, using additives is permitted. However, in some cases, additives are not desirable due to packaging design or filling substance properties. This leads to deviations from the initial gross mass definition. Hence, a certain drop height adjustment is necessary to achieve the required impact loading. Laboratories frequently adjust drop height assuming a perfectly elastic collision that is inaccurate. Appropriate adjustment is not trivial due to energy conversion processes, for example, plastic deformation. In this work, a test stand
KW - Corrugated fibreboard box
KW - Dangerous goods packagings
KW - Drop test
KW - Impact target
KW - Mechanical response
KW - Structural dynamics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614138
DO - https://doi.org/10.1002/pts.2858
SP - 1
EP - 18
PB - Wiley
AN - OPUS4-61413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cios, G.
A1 - Winkelmann, A.
A1 - Nolze, Gert
A1 - Tokarski, T.
A1 - Jany, B. R.
A1 - Bala, P.
T1 - EBSD and TKD analyses using inverted contrast Kikuchi diffraction patterns and alternative measurement geometries
N2 - Electron backscatter diffraction (EBSD) patterns can exhibit Kikuchi bands with inverted contrast due to anomalous absorption. This can be observed, for example, on samples with nanoscale topography, in case of a low tilt backscattering geometry, or for transmission Kikuchi diffraction (TKD) on thicker samples. Three examples are discussed where contrast-inverted physics-based simulated master patterns have been applied to find the correct crystal orientation. As first EBSD example, self-assembled gold nanostructures made of Au fcc and Au hcp phases on single-crystal germanium were investigated. Gold covered about 12% of the mapped area, with only two thirds being successfully interpreted using standard Hough-based indexing. The remaining third was solved by brute force indexing using a contrast-inverted master pattern. The second EBSD example deals with maps collected at a non-tilted surface instead of the commonly used 70◦ tilted one. As TKD example, a jet-polished foil made of duplex stainless steel 2205 was examined. The thin part close to the hole edge producing normal-contrast patterns were standard indexed. The areas of the foil that become thicker with increasing distance from the edge of the hole produce contrast-inverted patterns. They covered three times the evaluable area and were successfully processed using the contrast-inverted master pattern. In the last example, inverted patterns collected at a non-tiled sample were mathematically inverted to normal contrast, and Hough/Radon-based indexing was successfully applied.
KW - EBSD
KW - TKD
KW - Contrast inversion
KW - Topography
KW - Kikuchi diffraction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613862
VL - 267
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weichert, Dorina
A1 - Kister, Alexander
A1 - Houben, Sebastian
A1 - Link, Patrick
A1 - Ernis, Gunar
ED - Kiyavash, Negar
ED - Mooij, Joris M.
T1 - Robust Entropy Search for Safe Efficient Bayesian Optimization
N2 - The practical use of Bayesian Optimization (BO) in engineering applications imposes special requirements: high sampling efficiency on the one hand and finding a robust solution on the other hand. We address the case of adversarial robustness, where all parameters are controllable during the optimization process, but a subset of them is uncontrollable or even adversely perturbed at the time of application. To this end, we develop an efficient information-based acquisition function that we call Robust Entropy Search (RES). We empirically demonstrate its benefits in experiments on synthetic and real-life data. The results show that RES reliably finds robust optima, outperforming state-of-the-art algorithms.
T2 - UAI 2024
CY - Barcelona, Spain
DA - 15.07.2024
KW - Bayesian Optimization
KW - Gaussian process
KW - Active learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613523
UR - https://proceedings.mlr.press/v244/weichert24a.html
SN - 2640-3498
VL - 244
SP - 3711
EP - 3729
PB - Proceedings of Machine Learning Research
AN - OPUS4-61352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bruns, Sebastian
A1 - Bayerlein, Bernd
A1 - Kryeziu, Jehona
A1 - Schaarschmidt, Jörg
A1 - Waitelonis, Jörg
A1 - Dolabella Portella, Pedro
A1 - Durst, Karsten
T1 - Seamless Science: Lifting Experimental Mechanical Testing Lab Data to an Interoperable Semantic Representation
N2 - The scientific landscape is undergoing rapid transformations with the advent of the digital age which revolutionizes research methodologies. In materials science and engineering, an adoption of modern data management techniques is desirable to maximize the efficiency and accessibility of research efforts. Traditional practices in testing laboratories are usually inadequate for efficient data acquisition and utilization as they lead to local storage and difficulty in publication and correlation with other results. Electronic laboratory notebooks (ELNs) are promising prospects in this respect. Semantic concepts and ontologies enhance interoperability by standardizing experimental data representation. An in‐laboratory pipeline seamlessly integrating an ELN with transformation scripts to convert experimental into interoperable data in a machine‐actionable format is created in this study as a proof of concept. Tensile test results and the corresponding tensile test ontology are used exemplary. Linking ELN data to semantic concepts enriches the stored information while improving interpretability and reusability. Involving undergraduate students builds a bridge between theory and practice during their training and promotes their digital skills. This study underscores the potential of ELNs and knowledge representations as beneficial means toward improved data management practices that enhance collaborative research and education while ensuring compatibility with evolving standards and technologies.
KW - Semantic Data
KW - Data Integration
KW - Tensile Test Ontology
KW - Electronic Lab Notebook
KW - Wissensrepräsentation
KW - Education
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618251
DO - https://doi.org/10.1002/adem.202401527
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-61825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gregório, Bruno J.R.
A1 - Ramos, Inês I.
A1 - Marques, Sara S.
A1 - Barreiros, Luísa
A1 - Magalhães, Luís M.
A1 - Schneider, Rudolf
A1 - Segundo, Marcela A.
T1 - Microcarrier-based fluorescent yeast estrogen screen assay for fast determination of endocrine disrupting compounds
N2 - The presence of endocrine-disrupting compounds (EDCs) in water poses a significant threat to human and animal health, as recognized by regulatory agencies throughout the world. The Yeast Estrogen Screen (YES) assay is an excellent method to evaluate the presence of these compounds in water due to its simplicity and capacity to assess the bioaccessible forms/fractions of these compounds. In the presence of a compound with estrogenic activity, Saccharomyces cerevisiae cells, containing a lacZ reporter gene encoding the enzyme β-galactosidase, are induced, the enzyme is synthesised, and released to the extracellular medium. In this work, a YES-based approach encompassing the use of a lacZ reporter gene modified strain of S. cerevisiae, microcarriers as solid support, and a fluorescent substrate, fluorescein di-β-D-galactopyranoside, is proposed, allowing for the assessment of EDCs’ presence after only 2 h of incubation. The proposed method provided an EC50 of 0.17 ± 0.03 nM and an LLOQ of 0.03 nM, expressed as 17β-estradiol. The assessment of different EDCs provided EC50 values between 0.16 and 1.2 × 103 nM. After application to wastewaters, similar results were obtained for EDCs screening, much faster, compared to the conventional 45 h spectrophotometric procedure using a commercial kit, showing potential for onsite high-throughput screening of environmental contamination.
KW - Biosensoren
KW - YES assay
KW - Endokrine Disruptoren
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602315
DO - https://doi.org/10.1016/j.talanta.2024.125665
VL - 271
SP - 1
EP - 7
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-60231
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Braymer, Joseph J.
A1 - Stehling, Oliver
A1 - Stümpfig, Martin
A1 - Rösser, Ralf
A1 - Spantgar, Farah
A1 - Blinn, Catharina M.
A1 - Mühlenhoff, Ulrich
A1 - Pierik, Antonio J.
A1 - Lill, Roland
T1 - Requirements for the biogenesis of [2Fe-2S] proteins in the human and yeast cytosol
N2 - The biogenesis of iron–sulfur (Fe/S) proteins entails the synthesis and trafficking of Fe/S clusters, followed by their insertion into target apoproteins. In eukaryotes, the multiple steps of biogenesis are accomplished by complex protein machineries in both mitochondria and cytosol. The underlying biochemical pathways have been elucidated over the past decades, yet the mechanisms of cytosolic [2Fe-2S] protein assembly have remained ill-defined. Similarly, the precise site of glutathione (GSH) requirement in cytosolic and nuclear Fe/S protein biogenesis is unclear, as is the molecular role of the GSH-dependent cytosolic monothiol glutaredoxins (cGrxs). Here, we investigated these questions in human and yeast cells by various in vivo approaches. [2Fe-2S] cluster assembly of cytosolic target apoproteins required the mitochondrial ISC machinery, the mitochondrial transporter Atm1/ABCB7 and GSH, yet occurred independently of both the CIA system and cGrxs. This mechanism was strikingly different from the ISC-, Atm1/ABCB7-, GSH-, and CIA-dependent assembly of cytosolic–nuclear [4Fe-4S] proteins. One notable exception to this cytosolic [2Fe-2S] protein maturation pathway defined here was yeast Apd1 which used the CIA system via binding to the CIA targeting complex through its C-terminal tryptophan. cGrxs, although attributed as [2Fe-2S] cluster chaperones or trafficking proteins, were not essential in vivo for delivering [2Fe-2S] clusters to either CIA components or target apoproteins. Finally, the most critical GSH requirement was assigned to Atm1-dependent export, i.e. a step before GSH-dependent cGrxs function. Our findings extend the general model of eukaryotic Fe/S protein biogenesis by adding the molecular requirements for cytosolic [2Fe-2S] protein maturation.
KW - Biokorrosion
KW - Hydrogenasen
KW - Microbially Induced Corrosion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602328
DO - https://doi.org/10.1073/pnas.2400740121
SN - 0027-8424
VL - 121
IS - 21
SP - 1
EP - 12
PB - Proceedings of the National Academy of Sciences
CY - Washington D.C.
AN - OPUS4-60232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dace, Elina
A1 - Cascavilla, Alessandro
A1 - Bianchi, Marco
A1 - Chioatto, Elisa
A1 - Zecca, Emy
A1 - Ladu, Luana
A1 - Yilan, Gülsah
T1 - Barriers to transitioning to a circular bio-based economy: Findings from an industrial perspective
N2 - The transition from a linear fossil-based to a circular bio-based economy represents an opportunity and a suitable pathway for achieving several sustainable development goals. However, the transition is a complex process since it requires transformative policies, purposeful innovation, access to finance, risk-taking capacity as well as new and sustainable business models and markets. Accordingly, the first step in this transition process is the identification of barriers that are hampering the transition to a sustainable circular bio-based economy. With this motivation in mind, this study reviews grey literature to identify barriers focusing on four critical sectors facing major challenges within the current linear economy and requiring a sustainable transition most urgently: construction, chemicals, plastics, and textile sectors. Employing an adapted STEEP methodology (Social, Technological, Economical, Environmental, Political), a total of 193 different barriers have been identified and clustered under six categories: cultural, technical, economic, environmental, governance, and structural. Regardless of the sector, cultural and structural barriers are identified as the most prominent; the lack of incentives for consumer behaviour change and lack of stakeholder collaboration were the most cited barriers among the literature records. From a value chain perspective, most of the barriers are related to the material processing and product manufacturing stage. Finally, potential solutions, extracted from the grey literature, are proposed to fill the gaps and overcome the identified barriers. Many of the identified barriers are common across the four investigated sectors, indicating the solutions or measures can be applicable in a wider perspective to promote the transition in the right direction.
KW - Circular Bio-based Economy
KW - Barriers
KW - Sustainability
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602062
DO - https://doi.org/10.1016/j.spc.2024.05.029
VL - 48
SP - 407
EP - 418
PB - Elsevier Ltd.
AN - OPUS4-60206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Groschke, Matthias
A1 - Becker, Roland
T1 - Comparison of carrier gases for the separation and quantification of mineral oil hydrocarbon (MOH) fractions using online coupled high performance liquid chromatography-gas chromatography-flame ionisation detection
N2 - On-line coupled high performance liquid chromatography-gas chromatography-flame ionisation detection (HPLC-GC-FID) was used to compare the effect of hydrogen, helium and nitrogen as carrier gases on the chromatographic characteristics for the quantification of mineral oil hydrocarbon (MOH) traces in food related matrices. After optimisation of chromatographic parameters nitrogen carrier gas exhibited characteristics equivalent to hydrogen and helium regarding requirements set by current guidelines and standardisation such as linear range, quantification limit and carry over. Though nitrogen expectedly led to greater peak widths, all required separations of standard compounds were sufficient and humps of saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) were appropriate to enable quantitation similar to situations where hydrogen or helium had been used. Slightly increased peak widths of individual hump components did not affect shapes and widths of the MOSH and MOAH humps were not significantly affected by the use of nitrogen as carrier gas. Notably, nitrogen carrier gas led to less solvent peak tailing and smaller baseline offset. Overall, nitrogen may be regarded as viable alternative to hydrogen or helium and may even extend the range of quantifiable compounds to highly volatile hydrocarbon eluting directly after the solvent peak.
KW - Mineral oil hydrocarobons
KW - Food
KW - Liquid chromatography
KW - Gas chromatography
KW - MOSH/MOAH
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601450
DO - https://doi.org/10.1016/j.chroma.2024.464946
SN - 0021-9673
VL - 1726
SP - 1
EP - 7
PB - Elsevier
CY - New York, NY
AN - OPUS4-60145
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schepers, Winfried
A1 - Kulke, D.
T1 - Cone penetration tests and dynamic soil properties
N2 - ISO 14837-32:2015 and DIN EN 1998-1/NA:2021 as well as prEN 1997-2:2022 allow for us-ing correlations between the results of in-situ soil penetration tests and shear wave velocity (or shear modulus) to determine soil properties to be used in dynamic analyses. While the ISO and prEN standards even provide some recommendations on specific correlations to be used, the DIN standard does not. Due to the statistical nature of such correlations their general applica-bility has to be verified. We collected data sets from test sites from Germany as well as New Zealand at which cone penetration tests (CPT) as well as seismic site investigation methods were conducted. These sites comprise sandy soils as well as clayey soils, mixed soils as well as glacial soils. We compare the results of several correlations between CPT results and shear wave velocity. The accuracy of such correlations is assessed with respect to the accuracy of seismic in-situ tests. It turns out that for clean sands such correlations between CPT and Vs have a similar order of variability as seismic in-situ tests conducted at the same site. The higher the fines portion of the soil, the higher the variability of the statistical correlations, and conse-quently the less the general applicability. For glacial soils and other special soil types usage of statistical correlations to determine dynamic soil properties is not recommended.
T2 - XII International Conference on Structural Dynamics
CY - Delft, Netherlands
DA - 02.07.2023
KW - Wave propagation
KW - Soil properties
KW - Dynamic excitation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604887
DO - https://doi.org/10.1088/1742-6596/2647/25/252005
VL - 2647
SP - 1
EP - 11
PB - IOP Publishing
CY - Bristol
AN - OPUS4-60488
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schepers, Winfried
A1 - Brinkgreve, RBJ
A1 - Appel, S.
T1 - Recommendations on finite element modelling of non-seismic excitation in soil-structure interaction problems
N2 - Nowadays geotechnical engineering firms have powerful software tools to extent their consult-ing business also into dynamic soil-structure interaction, which before has been restricted to a rather small community of specialized experts in this field, and they certainly do. This is par-ticularly true with respect to non-seismic sources, that is all kinds of human induced vibrations. Hence, there is a demand from clients as well as from contractors to have guidance on the re-quirements as well as the limits of numerical modelling of soil-structure interaction. From the literature as well as from relevant standards, recommendations for the numerical modelling of soil-structure interaction problems involving seismic actions are well known, e. g. ASCE/SEI 4-16. There are, however, some particularities when dealing with human-induced vibrations, which are absent in seismic analyses. For human-induced excitations very little specific guid-ance has been published in the past. A machine foundation on a homogeneous half space ex-cited by harmonic loads with excitation frequency between 4 Hz and 64 Hz has been ana-lysed by means of several commercially available software packages. Parametric studies have been performed to verify if recommendations for seismic soil-structure analyses are valid for non-seismic analyses as well. This paper provides details on the benchmark example and the most important conclusions from the undertaken parametric studies.
T2 - XII International Conference on Structural Dynamics
CY - Delft, Netherlands
DA - 02.07.2023
KW - Numerische Analysen
KW - Referenzbeispiel
KW - Maschinenfundament
KW - Wellenausbreitung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604931
DO - https://doi.org/10.1088/1742-6596/2647/8/082014
SN - 1742-6596
VL - 2647
IS - 25
SP - 1
EP - 13
PB - IOP Publishing
AN - OPUS4-60493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hirsch, Philipp Daniel
A1 - Kunji Purayil, Sruthi Krishna
A1 - Lecompagnon, Julien
A1 - Hassenstein, Christian
A1 - Ziegler, Mathias
T1 - Robotergestützte 3D-Scans und Laserthermografie zur Prüfung an komplexen Bauteilen auf Risse
N2 - Die Integration von Automation und Robotik in die Prüfprozesse ermöglicht die
Untersuchung komplexer Bauteile. Diese Studie präsentiert die robotergestützte
Laserthermografie, um Risse in solchen Bauteilen zu identifizieren und analysieren. Diese Technik ermöglicht die automatisierte Rissprüfung welche im Vergleich zur Farbeindringprüfung auf viele, meist manuelle, Arbeitsschritte sowie die notwendigen Chemikalien verzichtet.
Zusätzlich wird ein automatisiertes Einscannen der Bauteile mithilfe eines
Linienscanners vorgestellt. Dieser Schritt ermöglicht eine detaillierte 3D-Rekonstruktion der Bauteilgeometrie und ermöglicht eine einfache Korrektur von Abweichungen in der Bauteilaufnahme und eröffnet Möglichkeiten zur adaptiven Bahnplanung bei Bauteilverformungen.
Die Rückprojektion der gefundenen Risse auf die Oberfläche des Bauteils kann
automatisiert erfolgen. Dieser Schritt erlaubt nicht nur die Identifikation der Risse, sondern auch eine genauere Analyse ihrer Geometrie und Lage am Bauteil.
Die Kombination von robotergestützter Laserthermografie, automatisiertem 3DScanning und Rückprojektion der Risse auf die Bauteiloberfläche eröffnet neue
Möglichkeiten in der zerstörungsfreien Prüfung von komplexen Bauteilen und erweitert damit mögliche Anwendungsfelder.
T2 - Jahrestagung der Deutschen Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) 2024
CY - Osnabrück, Germany
DA - 06.05.2024
KW - ZFP4.0
KW - Automatisierung
KW - Thermografie
KW - Laser
KW - Roboter
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604811
UR - https://www.ndt.net/?id=29520
VL - 182
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-60481
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maulas, Kryzzyl M.
A1 - Paredes, Charla S.
A1 - Tabelin, Carlito Baltazar
A1 - Jose, Mark Anthony
A1 - Opiso, Einstine M.
A1 - Arima, Takahiko
A1 - Park, Ilhwan
A1 - Mufalo, Walubita
A1 - Ito, Mayumi
A1 - Igarashi, Toshifumi
A1 - Phengsaart, Theerayut
A1 - Villas, Edrhea
A1 - Dagondon, Sheila L.
A1 - Metillo, Ephrime B.
A1 - Uy, Mylene M.
A1 - Manua, Al James A.
A1 - Villacorte-Tabelin, Mylah
T1 - Isolation and Characterization of Indigenous Ureolytic Bacteria from Mindanao, Philippines: Prospects for Microbially Induced Carbonate Precipitation (MICP)
N2 - Microbially induced carbonate precipitation (MICP), a widespread phenomenon in nature, is gaining attention as a low-carbon alternative to ordinary Portland cement (OPC) in geotechnical engineering and the construction industry for sustainable development. In the Philippines, however, very few works have been conducted to isolate and identify indigenous, urease-producing (ureolytic) bacteria suitable for MICP. In this study, we isolated seven, ureolytic and potentially useful bacteria for MICP from marine sediments in Iligan City. DNA barcoding using 16s rDNA identified six of them as Pseudomonas stutzeri, Pseudomonas pseudoalcaligenes, Bacillus paralicheniformis, Bacillus altitudinis, Bacillus aryabhattai, and Stutzerimonas stutzeri but the seventh was not identified since it was a bacterial consortium. Bio-cementation assay experiments showed negligible precipitation in the control (without bacteria) at pH 7, 8, and 9. However, precipitates were formed in all seven bacterial isolates, especially between pH 7 and 8 (0.7–4 g). Among the six identified bacterial species, more extensive precipitation (2.3–4 g) and higher final pH were observed in S. stutzeri, and B. aryabhattai, which indicate better urease production and decomposition, higher CO2 generation, and more favorable CaCO3 formation. Characterization of the precipitates by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR) confirmed the formation of three carbonate minerals: calcite, aragonite, and vaterite. Based on these results, all six identified indigenous, ureolytic bacterial species from Iligan City are suitable for MICP provided that the pH is controlled between 7 and 8. To the best of our knowledge, this is the first report of the urease-producing ability and potential for MICP of P. stutzeri, P. pseudoalcaligenes, S. stutzeri, and B. aryabhattai.
KW - Calcium carbonate
KW - Microbially induced carbonate precipitation (MICP)
KW - Ureolytic bacteria
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600888
DO - https://doi.org/10.3390/min14040339
VL - 14
IS - 4
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-60088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poka, Konstantin
A1 - Ali, Sozol
A1 - Saeed, Waleed
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Design and implementation of a machine log for PBF-LB/M on basis of IoT communication architectures and an ETL pipeline
N2 - AbstractPowder Bed Fusion with Laser Beam of Metals (PBF-LB/M) has gained more industrial relevance and already demonstrated applications at a small series scale. However, its widespread adoption in various use cases faces challenges due to the absence of interfaces to established Manufacturing Execution Systems (MES) that support customers in the predominantly data-driven quality assurance. Current state-of-the-art PBF-LB/M machines utilize communication architectures, such as OPC Unified Architecture (OPC UA), Message Queuing Telemetry Transport (MQTT) and Representational State Transfer Application Programming Interface (REST API). In the context of the Reference Architecture Model Industry 4.0 (RAMI 4.0) and the Internet of Things (IoT), the assets, particularly the physical PBF-LB/M machines, already have an integration layer implemented to communicate data such as process states or sensor values. Missing is an MES component acting as a communication and information layer. To address this gap, the proposed Extract Transform Load (ETL) pipeline aims to extract relevant data from the fabrication of each build cycle down to the level of scan vectors and additionally to register process signals. The suggested data schema for archiving each build cycle adheres to all terms defined by ISO/TC 261—Additive Manufacturing (AM). In relation to the measurement frequency, all data are reorganized into entities, such as the AM machine, build cycle, part, layer, and scan vector. These scan vectors are stored in a runtime-independent format, including all metadata, to be valid and traceable. The resulting machine log represents a comprehensive documentation of each build cycle, enabling data-driven quality assurance at process level.
KW - FAIR data
KW - Data-driven quality assurance
KW - Laser powder bed fusion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601256
DO - https://doi.org/10.1007/s40964-024-00660-7
SN - 2363-9512
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-60125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Stephan
A1 - Hoffmann, Holger
A1 - Garbe, Leif-Alexander
A1 - Harrer, Andrea
A1 - Steiner, Markus
A1 - Himly, Martin
A1 - Schneider, Rudolf
T1 - Re-assessment of monoclonal antibodies against diclofenac for their application in the analysis of environmental waters
N2 - The non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF) is an important environmental contaminant occurring in surface waters all over the world, because, after excretion, it is not adequately removed from wastewater in sewage treatment plants. To be able to monitor this pollutant, highly efficient analytical methods are needed, including immunoassays. In a medical research project, monoclonal antibodies against diclofenac and its metabolites had been produced. Based on this monoclonal anti-DCF antibody, a new indirect competitive enzyme-linked immunosorbent assay (ELISA) was developed and applied for environmental samples. The introduction of a spacer between diclofenac and the carrier protein in the coating conjugate led to higher sensitivity. With a test midpoint of 3 mg L−1 and a measurement range of 1–30 mg L−1, the system is not sensitive enough for direct analysis of surface water. However, this assay is quite robust against matrix influences and can be used for wastewater. Without adjustment of the calibration, organic solvents up to 5%, natural organic matter (NOM) up to 10 mg L−1, humic acids up to 2.5 mg L−1, and salt concentrations up to 6 g L−1 NaCl and 75 mg L−1 CaCl2 are tolerated. The antibody is also stable in a pH range from 3 to 12. Cross-reactivity (CR) of 1% or less was determined for the metabolites 40-hydroxydiclofenac (40-OH-DCF), 5-hydroxydiclofenac (5-OH-DCF), DCF lactam, and other NSAIDs. Relevant cross-reactivity occurred only with an amide derivative of DCF, 6-aminohexanoic acid (DCF-Ahx), aceclofenac (ACF) and DCF methyl ester (DCF-Me) with 150%, 61% and 44%, respectively. These substances, however, have not been found in samples. Only DCF-acyl glucuronide with a cross-reactivity of 57% is of some relevance. For the first time, photodegradation products were tested for cross-reactivity. With the ELISA based on this antibody, water samples were analysed. In sewage treatment plant effluents, concentrations in the range of 1.9–5.2 mg L−1 were determined directly, with recoveries compared to HPLC-MS/MS averaging 136%.
Concentrations in lakes ranged from 3 to 4.4 ng L−1 and were, after pre-concentration, determined with an average recovery of 100%
KW - Antikörper
KW - Immunoassay
KW - Wasser
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602280
DO - https://doi.org/10.1039/d3ay01333b
VL - 16
IS - 21
SP - 3349
EP - 3363
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-60228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Galleani, Gustavo
A1 - Lodi, Thiago A.
A1 - Conner, Robin L.
A1 - Jacobsohn, Luiz G.
A1 - de Camargo, Andrea Simone Stucchi
T1 - Photoluminescence and X-ray induced scintillation in Gd3+-Tb3+ co-doped fluoride-phosphate glasses, and derived glass-ceramics containing NaGdF4 nanocrystals
N2 - The glass system (50NaPO3–20BaF2–10CaF2–20GdF3)-xTbCl3 with x = 0.3, 1, 3, 5, and 10 wt % was investigated. We successfully produced transparent glass ceramic (GC) scintillators with x = 1 through a melt-quenching process followed by thermal treatment. The luminescence and crystallization characteristics of these materials were thoroughly examined using various analytical methods. The nanocrystallization of Tb3+-doped Na5Gd9F32 within the doped fluoride-phosphate glasses resulted in enhanced photoluminescence (PL) and radioluminescence (RL) of the Tb3+ ions. The GC exhibited an internal PL quantum yield of 33 % and the integrated RL intensity across the UV-visible range was 36 % of that reported for the commercial BGO powder scintillator. This research showcases that Tb-doped fluoridephosphate GCs containing nanocrystalline Na5Gd9F32 have the potential to serve as efficient scintillators while having lower melting temperature compared to traditional silicate and germanate glasses.
KW - Glass scintillator
KW - Fluoride phosphate glasses
KW - Gd3+
KW - Tb3+
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603588
DO - https://doi.org/10.1016/j.omx.2023.100288
VL - 21
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-60358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tatzel, Michael
A1 - Oelze, Marcus
A1 - Frick, Daniel A.
A1 - Di Rocco, Tommaso
A1 - Liesegang, Moritz
A1 - Stuff, Maria
A1 - Wiedenbeck, Michael
T1 - Silicon and oxygen isotope fractionation in a silicified carbonate rock
N2 - Silicon isotope fractionation during silicification is poorly understood and impedes our ability to decipher paleoenvironmental conditions from Si isotopes in ancient cherts. To investigate isotope fractionation during silica-for-carbonate replacement we analyzed the microscale Si and O isotope composition in different silica phases in a silicified zebra dolostone as well as their bulk δ18O and Δ’17O compositions. The subsequent replacement of carbonate layers is mimicked by decreasing δ18O and δ30Si. The textural relationship and magnitude of Si and O isotope fractionation is best explained by near-quantitative silica precipitation in an open system with finite Si. A Rayleigh model for silicification suggests positive Ɛ30/28Si during silicification, conforming with predictions for isotope distribution at chemical equilibrium from ab-initio models. Application of the modelled Ɛ30Si-T relationship yields silicification temperatures of approx. 50°C. To reconcile the δ18Ochert composition with these temperatures, the δ18O of the fluid must have been between -2.5 and -4 ‰, compositions for which the quartz phases fall close to the oxygen equilibrium fractionation line in three-isotope space. Diagenetic silica replacement appears to occur in O and Si isotopic equilibrium allowing reconstructions of temperatures of silicification from Si isotopes and derive the δ18O composition of the fluid – a highly desired value needed for accurate reconstructions of the temperature- and δ18O histories of the oceans.
KW - Silicon isotopes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603430
DO - https://doi.org/10.1016/j.chemgeo.2024.122120
SN - 0009-2541
VL - 658
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wosniok, Aleksander
A1 - Königsbauer, Korbinian
A1 - Nöther, Nils
A1 - Färber, Jan
A1 - Schaller, M.-Barbara
A1 - Krebber, Katerina
T1 - Distributed polymer optical fiber sensors using digital I-OFDR for geotechnical infrastructure health monitoring
N2 - We present a distributed polymer optical fiber sensor system for deformation monitoring of geotechnical infrastructure. The sensor system is based on the digital incoherent optical frequency domain reflectometry (I-OFDR) for the detection of local strain events along a perfluorinated polymer optical fiber (PF-POF) used as a sensing fiber. For the best possible load transfer, the PF-POFs were integrated onto geosynthetics which pose a sensor carrier for the sensing fiber. By using elastic PF-POF instead of a standard glass fiber as a sensing fiber the strain range of geosynthetics-integrated fiber optic sensors could be extended up to 10 % in accordance with the end-user requirements.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Digital I-OFDR
KW - Distributed polymer optical fiber sensor
KW - Ddistributed strain sensing
KW - Smart geosynthetics
KW - Structural health monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603096
SP - 1
EP - 7
PB - NDT.net
AN - OPUS4-60309
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Charmi, Amir
A1 - Heimann, Jan
A1 - Duffner, Eric
A1 - Hashemi, Seyedreza
A1 - Prager, Jens
T1 - Application of deep learning for structural health monitoring of a composite overwrapped pressure vessel undergoing cyclic loading
N2 - Structural health monitoring (SHM) using ultrasonic-guided waves (UGWs) enables continuous monitoring of components with complex geometries and provides extensive information about their structural integrity and their overall condition. Composite overwrapped pressure vessels (COPVs) used for storing hydrogen gases at very high pressures are an example of a critical infrastructure that could benefit significantly from SHM. This can be used to increase the periodic inspection intervals, ensure safe operating conditions by early detection of anomalies, and ultimately estimate the remaining lifetime of COPVs. Therefore, in the digital quality infrastructure initiative (QI-Digital) in Germany, an SHM system is being developed for COPVs used in a hydrogen refueling station. In this study, the results of a lifetime fatigue test on a Type IV COPV subjected to many thousands of load cycles under different temperatures and pressures are presented to demonstrate the strengths and challenges associated with such an SHM system. During the cyclic testing up to the final material failure of the COPV, a sensor network of fifteen surface-mounted piezoelectric (PZT) wafers was used to collect the UGW data. However, the pressure variations, the aging process of the COPV, the environmental parameters, and possible damages simultaneously have an impact on the recorded signals. This issue and the lack of labeled data make signal processing and analysis even more demanding. Thus, in this study, semi-supervised, and unsupervised deep learning approaches are utilized to separate the influence of different variables on the UGW data with the final aim of detecting and localizing the damage before critical failure.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Structural health monitoring
KW - Deep learning
KW - Ultrasonic-guided waves
KW - Anomaly detection
KW - Damage localization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607396
DO - https://doi.org/10.58286/29751
SP - 1
EP - 8
AN - OPUS4-60739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krone, David
A1 - Esche, Erik
A1 - Skiborowski, Mirko
A1 - Repke, Jens-Uwe
T1 - Optimization-based process synthesis by phenomena-based building blocks and an MINLP framework featuring structural screening
N2 - An existing approach for optimization-based process synthesis with abstracted phenomena-based building blocks (PBB) is extended by implementing it into a novel MINLP framework with structural screening. Consistency across the multilayer MINLP framework is guaranteed by creating a MathML/XML data model and subsequently exporting the code to the different program parts. The novel framework focuses both on fidelity by implementing thermodynamically sound models and on generality by employing a state-space superstructure that spans a large search space. In order to retain tractability, we insert a structural screening layer which prescreens based on binary decision variables of the superstructure by graph- and rule-based analyses, penalizing non-physical instances without solution of the underlying MINLP. The MINLP framework is successfully applied on two challenging synthesis tasks to determine the separation of the feed streams of benzene and toluene, as well as of n-pentane, n-hexane, and n-heptane utilizing superstructures with two, respectively four PBB.
KW - Process synthesis
KW - Superstructure optimization
KW - Distillation
KW - Mathematical programming
KW - Structural screening
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621955
DO - https://doi.org/10.1016/j.compchemeng.2024.108955
VL - 194
SP - 1
EP - 19
PB - Elsevier Ltd.
AN - OPUS4-62195
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Johann, Sergej
A1 - Stürenberg, Jan
A1 - Tandon, Aditya
T1 - Robotergestütztes Bauwerksmonitoring basierend auf eingebetteter Sensorik
N2 - In den letzten Jahrzehnten hat sich das Bauwerksmonitoring (engl. „Structural Health Monitoring“, SHM) zu einer nützlichen Ergänzung routinemäßiger Inspektionen entwickelt. SHM ermöglicht die frühzeitige Erkennung von Schäden an Bauwerken und dadurch die frühe, und somit kostengünstige, Durchführung von Reparatur- und Wartungsarbeiten. Mit dem Aufkommen drahtloser Technologien und Fortschritten in der Informations- und Kommunikationstechnologie werden Bauwerke zunehmend mit drahtlosen Sensorknoten ausgestattet, um für SHM relevante Bauwerksdaten zu erfassen, zu analysieren und zu übertragen. Eine vielversprechende Methode für SHM ist die direkte Einbettung von Sensoren in den Beton. In diesem Beitrag wird ein Sensorsystem zur Einbettung in Beton vorgestellt, das in der Lage ist, die im Beton aufgenommenen Bauwerksdaten auszuwerten. Die Sensoren werden bei Bedarf von vierbeinigen Robotern mittels Radio Frequency Identification (RFID) ausgelesen und mit Energie versorgt, was einen automatisierten und effizienten Prozess ermöglicht. Der prototypische Prozess zur automatischen Erfassung von Bauwerksdaten mit eingebetteter Sensorik und vierbeinigen Robotern wird durch Tests in einer Büroumgebung validiert. Die Ergebnisse der Tests bestätigen die automatische und effiziente Erfassung von Bauwerksdaten, die eine frühzeitige Erkennung von Bauwerksschäden, auch von nicht sichtbaren Schäden, ermöglicht, und eine folgerichtige Weiterentwicklung des
modernen Bauwerksmonitorings repräsentiert.
T2 - 35. Forum Bauinformatik
CY - Hamburg, Germany
DA - 18.09.2024
KW - Radio Frequency Identification (RFID)
KW - Bauwerksmonitoring (SHM)
KW - Eingebettete Sensorik
KW - Vierbeinige Roboter
KW - Autonome Navigation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621890
DO - https://doi.org/10.15480/882.13502
SP - 139
EP - 146
AN - OPUS4-62189
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - McMahon, Dino Peter
A1 - Natsopoulou, M. E.
A1 - Doublet, V.
A1 - Fürst, M.
A1 - Weging, S.
A1 - Brown, M. J. F.
A1 - Gogol-Döring, A.
A1 - Paxton, R. J.
T1 - Elevated virulence of an emerging viral genotype as a driver of honeybee loss
N2 - Emerging infectious diseases (EIDs) have contributed significantly to the current biodiversity crisis, leading to widespread epidemics and population loss. Owing to genetic variation in pathogen virulence, a complete understanding of species decline requires the accurate identification and characterization of EIDs. We explore this issue in the Western honeybee, where increasing mortality of populations in the Northern Hemisphere has caused major concern. Specifically, we investigate the importance of genetic identity of the main suspect in mortality, deformed wing virus (DWV), in driving honeybee loss. Using laboratory experiments and a systematic field survey, we demonstrate that an emerging DWV genotype (DWV-B) is more virulent than the established DWV genotype (DWV-A) and is widespread in the landscape. Furthermore, we show in a simple model that colonies infected with DWV-B collapse sooner than colonies infected with DWV-A. We also identify potential for rapid DWV evolution by revealing extensive genome-wide recombination in vivo. The emergence of DWV-B in naive honeybee populations, including via recombination with DWV-A, could be of significant ecological and economic importance. Our findings emphasize that knowledge of pathogen genetic identity and diversity is critical to understanding drivers of species decline.
KW - Virulence
KW - Emerging infectious disease
KW - Pollinator
KW - Decline
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-368030
DO - https://doi.org/10.1098/rspb.2016.0811
SN - 0962-8452
VL - 283
IS - 1833
SP - Article 0811, 1
EP - 8
AN - OPUS4-36803
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunte, Hans-Jörg
A1 - Lentzen, G.
A1 - Galinski, E.
T1 - Industrial production of the cell protectant ectoine: protection mechanisms, processes, and products
N2 - Bacteria, Archaea and Eukarya can adapt to Saline environments by accumulating compatible solutes in order to maintain an osmotic equilibrium. Compatible solutes are of diverse chemical structure (sugars, polyols, amino acid derivatives) and are beneficial for bacterial cells not only as osmoregulatory solutes, but also as protectants of proteins by mitigating detrimental effects of freezing, drying and high temperatures. The aspartate derivative ectoine is a wide spread compatible solute in Bacteria and possesses additional protective properties compared with other compatible solutes, and stabilizes even whole cells against stresses such as UV radiation or cytotoxins. The protective properties of ectoine for proteins can be explained by its strong (kosmotropic) interaction with water and subsequent exclusion from Protein surface, the decrease of the solubility of the peptide backbone and the strengthening of intramolecular hydrogen bonds (secondary structures). The stabilizing and UV-protective properties of ectoine attracted industry, which saw the potential to market ectoine as a novel active component in health care products and cosmetics. In joint efforts of industry and research large-scale fermentation procedures have been developed with the halophilic bacterium Halomonas elongata used as a producer strain. The two key technologies that allow for the annual production of ectoine on a scale of tons are the bacterial milking procedure and the development and application of ectoine-excreting mutants (“leaky” mutant). The details of these two procedures including the strain development and Fermentation processes will be introduced and current and future applications of ectoine will be discussed.
KW - Bacterial milking
KW - Batch fermentation
KW - Continuous culture
KW - Ectoine excretion
KW - Hofmeister effect
KW - Kosmotrope
KW - “leaky” mutant
KW - Osmophobic effect
KW - Protein protection
KW - Preferential exclusion
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376805
DO - https://doi.org/10.2174/22115501113026660037
SN - 2211-551X
VL - 3
IS - 1
SP - 10
EP - 25
PB - Bentham Science
AN - OPUS4-37680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zscherpel, Uwe
A1 - Ewert, Uwe
T1 - Electronic reference images for flaw indications in welds and castings
N2 - Since decades the evaluation of flaw indications on radiographs from welds or castings are based on well accepted reference film catalogues from organizations like IIW (weldments), ASTM (castings) or DGZfP (D5 recommendation on heavy steel castings). Today, the transformation of classical film radiography to the digital world is in full progress. Some ASTM standards do not permit the evaluation of digital radiographs in reference to film catalogues. Therefore, these reference film catalogues have to be converted into the digital age too. BAM is supporting this transition by high definition film scanning. The result is a corresponding reference image catalogue. The different standard organizations selected different ways to distribute the digital data. ASTM used high definition film scanning at 10 μm pixel size and distribution of a huge amount of high-res data via DVD. The user sub-samples these high-res data during catalogue import to the resolution of his system. The comparison is done by synchronized image viewing on the computer work station. IIW recently decided to distribute their ISO 5817 reference images installed on tablets, which are used for image viewing too. The tablet image has to be compared with the digital image on the system monitor. DGZfP transformed their D5 reference radiographs into a PDF for monitor viewing. This is the simplest and cheapest solution, but still allows the full usage of the catalogue in the digital era. The status of ongoing work in progress will be discussed.
T2 - WCNDT 2016
CY - Munich, Germany
DA - 13.06.2016
KW - Castings
KW - NDT
KW - RT
KW - Radiography
KW - Discontinuities
KW - Catalogues
KW - Welds
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377306
UR - http://ndt.net/?id=19310
SN - 1435-4934
VL - 21
IS - 7
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-37730
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosemann, Paul
A1 - Müller, Christina
A1 - Meyer, A.
A1 - Halle, T.
T1 - Influence of nitrogen on the corrosion resistance of martensitic stainless steels
N2 - The corrosion resistance of martensitic stainless steels (MSS) depends strongly on the chemical composition and the applied heat treatment. Both determines the distribution of the alloying elements in the microstructure and the resulting material properties. The addition of nitrogen is known to be beneficial for the pitting corrosion resistance of stainless steels. In case of MSS this effect is not only connected to nitrogen itself because nitrogen can be used to substitute carbon which also influences the result of the heat treatment process. This paper shows the effect of nitrogen on the corrosion resistance in relation to the hardening process of MSS. Therefore the effects of austenitization duration, austenitization temperature and cooling rate on microstructure, hardness and corrosion resistance were studied on the MSS X30CrMoN15 1 and X50CrMoV15. The effect of different cooling rates was studied in the range of > 100 K/s down to 1 K/s using the jominy end quench test. The changes in corrosion resistance were detected with electrochemical potentiodynamic reactivation (EPR) and by the determination of critical pitting potentials. Besides this experimental approach thermodynamic calculations with the software thermocalc will be presented and used for the interpretation of the effect of nitrogen on the corrosion resistance of MSS.
T2 - 18th Chemnitz Seminar on Materials Engineering – 18. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
KW - Martensitic stainless steels
KW - Corrosion resistance
KW - Heat treatment
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366956
DO - https://doi.org/10.1088/1757-899X/118/1/011002
VL - 118
IS - 1
SP - 19
EP - 19
PB - IOP Publishing
AN - OPUS4-36695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherb, Tobias
A1 - Kimber, S. A. J.
A1 - Stephan, Christiane
A1 - Henry, P. F.
A1 - Schumacher, G.
A1 - Escolástico, S.
A1 - Serra, J. M.
A1 - Seeger, J.
A1 - Just, J.
A1 - Hill, A.H.
A1 - Banhart, J.
T1 - Nanoscale order in the frustrated mixed conductor La5.6WO12-Delta
N2 - This article reports a comprehensive investigation of the average and local structure of La5.6WO12-δ, which has excellent mixed proton, electron and oxide ion conduction suitable for device applications. Synchrotron X-ray and neutron powder diffraction show that a cubic fluorite supercell describes the average structure, with highly disordered lanthanum and oxide positions. On average, the tungsten sites are sixfold coordinated and a trace [3.7 (1.3)%] of anti-site disorder is detected. In addition to sharp Bragg reflections, strong diffuse neutron scattering is observed, which hints at short-range order. Plausible local configurations are considered and it is shown that the defect chemistry implies a simple 'chemical exchange' interaction that favours ordered WO6 octahedra. The local model is confirmed by synchrotron X-ray pair distribution function analysis and EXAFS experiments performed at the La K and W L-3 edges. It is shown that ordered domains of similar to 3.5 nm are found, implying that mixed conduction in La5.6WO12-δ is associated with a defective glassy-like anion sublattice. The origins of this ground state are proposed to lie in the nonbipartite nature of the face-centred cubic lattice and the pairwise interactions which link the orientation of neighbouring octahedral WO6 sites. This 'function through frustration' could provide a means of designing new mixed conductors.
KW - neutron diffraction
KW - x-ray diffraction
KW - proton conductors
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366756
DO - https://doi.org/10.1107/S1600576716006415
SN - 1600-5767
VL - 49
IS - Issue 3
SP - 997
EP - 1008
PB - International Union of Crystallography
CY - Chester, UK
AN - OPUS4-36675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meiling, T.
A1 - Cywinski, P.
A1 - Bald, Ilko
T1 - White carbon: Fluorescent carbon nanoparticles with tunable quantum yield in a reproducible green synthesis
N2 - In this study, a new reliable, economic, and environmentally-friendly one-step synthesis is established to obtain carbon nanodots (CNDs) with well-defined and reproducible photoluminescence (PL) properties via the microwave-assisted hydrothermal treatment of starch and Tris-acetate-EDTA (TAE) buffer as carbon sources. Three kinds of CNDs are prepared using different sets of above mentioned starting materials. The as-synthesized CNDs: C-CND (starch only), N-CND 1 (starch in TAE) and N-CND 2 (TAE only) exhibit highly homogenous PL and are ready to use without need for further purification.
The CNDs are stable over a long period of time (>1 year) either in solution or as freeze-dried powder. Depending on starting material, CNDs with PL quantum yield (PLQY) ranging from less than 1% up to 28% are obtained. The influence of the precursor concentration, reaction time and type of additives on the optical properties (UV-Vis absorption, PL emission spectrum and PLQY) is carefully investigated, providing insight into the chemical processes that occur during CND formation. Remarkably, upon freeze-drying the initially brown CND-solution turns into a non-fluorescent white/slightly Brown powder which recovers PL in aqueous solution and can potentially be applied as fluorescent marker in bio-imaging, as a reduction agent or as a photocatalyst.
KW - Carbon dots
KW - Quantum yield
KW - Fluorescence
KW - Nanoparticles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367204
DO - https://doi.org/10.1038/srep28557
VL - 6
SP - Article 28557, 1
EP - 9
PB - Nature Publishing Group
AN - OPUS4-36720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nilsson, R. H.
A1 - Taylor, A. F. S.
A1 - Adams, R. I.
A1 - Baschien, C.
A1 - Bengtsson-Palme, J.
A1 - Cangren, P.
A1 - Coleine, C.
A1 - Iršėnaitė, R.
A1 - Martin-Sanchez, Pedro Maria
A1 - Meyer, W.
A1 - Oh, S.-Y.
A1 - Sampaio, J. P.
A1 - Seifert, K. A.
A1 - Sklenář, F.
A1 - Stubbe, D.
A1 - Suh, S.-O.
A1 - Summerbell, R.
A1 - Svantesson, S.
A1 - Unterseher, M.
A1 - Visagie, C. M.
A1 - Weiss, M.
A1 - Woudenberg, J. HC.
A1 - Wurzbacher, C.
A1 - Van den Wyngaert, S.
A1 - Yilmaz, N.
A1 - Yurkov, A.
A1 - Kõljalg, U.
A1 - Abarenkov, K.
A1 - Daniel, H.-M.
A1 - Glassman, S. I.
A1 - Hirooka, H.
A1 - Irinyi, L.
T1 - Taxonomic annotation of public fungal ITS sequences from the built environment – a report from an April 10–11, 2017 workshop (Aberdeen, UK)
N2 - Recent DNA-based studies have shown that the built environment is surprisingly rich in fungi. These indoor fungi – whether transient visitors or more persistent residents – may hold clues to the rising levels of human allergies and other medical and building-related health problems observed globally. The taxo¬nomic identity of these fungi is crucial in such pursuits. Molecular identification of the built mycobiome is no trivial undertaking, however, given the large number of unidentified, misidentified, and technically compromised fungal sequences in public sequence databases. In addition, the sequence metadata required to make informed taxonomic decisions – such as country and host/substrate of collection – are often lacking even from reference and ex-type sequences. Here we report on a taxonomic annotation workshop (April 10–11, 2017) organized at the James Hutton Institute/University of Aberdeen (UK) to facilitate reproducible studies of the built mycobiome. The 32 participants went through public fungal ITS bar¬code sequences related to the built mycobiome for taxonomic and nomenclatural correctness, technical quality, and metadata availability. A total of 19,508 changes – including 4,783 name changes, 14,121 metadata annotations, and the removal of 99 technically compromised sequences – were implemented in the UNITE database for molecular identification of fungi (https://unite.ut.ee/) and shared with a range of other databases and downstream resources. Among the genera that saw the largest number of changes were Penicillium, Talaromyces, Cladosporium, Acremonium, and Alternaria, all of them of significant importance in both culture-based and culture-independent surveys of the built environment.
KW - Indoor mycobiome
KW - Built environment
KW - Molecular identification
KW - Fungi
KW - Taxonomy
KW - Systematics
KW - Sequence annotation
KW - Metadata
KW - Open data
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438949
DO - https://doi.org/10.3897/mycokeys.28.20887
SN - 1314-4049
SN - 1314-4057
VL - 28
SP - 65
EP - 82
PB - Pensoft Publishers
CY - Washington, DC
AN - OPUS4-43894
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Hilgenberg, Kai
T1 - Damage development and damage tolerance of structures manufactured by selective laser melting - a review
N2 - The additive manufacturing technology of Selective Laser Melting (SLM) experiences a rapid development within an increasing marked of quite different application fields. The properties of SLM materials and structures are influenced by a number of tech-nological parameters such as the metal powder (particle size, homogeneity, cleanliness), the laser tool (power, beam diameter, pulse lengths), the scanning operation (speed, sequence and orientation of melting paths), parameters of the over-all equipment (design and preheating of the base plate, currents and turbulence in the protective gas atmosphere) and, last not least, the hatching strategy including the build-up direction of the structure with respect to the loading direction of the component.
For the perspective use of SLM structures as load carrying, safety-relevant components the knowledge of their mechanical properties is necessary. It is essential to understand these in the context of the manufacturing-related features and at the back-ground of the basic characteristics of metallic materials: crystal lattice, microstructure and material defects. The paper provides an overview on factors which affect the mechanical parameters stiffness, strength, ductility, toughness, fatigue crack propagation and fatigue strength in the context of selective laser melting.
T2 - FDMD 2017
CY - Lecco, Italy
DA - 19.09.2017
KW - Fatigue strength
KW - Fracture mechanics
KW - Initial crack size
KW - Short crack propagation
KW - Multiple crack propagation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438511
DO - https://doi.org/10.1016/j.prostr.2017.11.071
SN - 2452-3216
VL - 7
SP - 141
EP - 148
PB - ScienceDirect
CY - Lecco, Italy
AN - OPUS4-43851
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Muelow-Stollin, Ulrike
A1 - Lehnik-Habrink, Petra
A1 - Kluge, Stephanie
A1 - Bremser, Wolfram
A1 - Piechotta, Christian
T1 - Efficiency Evaluation of Extraction Methods for Analysis of OCPs and PCBs in Soils of Varying TOC
N2 - Organochlorine pesticides and polychlorinated biphenyls are toxic, carcinogenic, and have a high potential for bioaccumulation. Due to their stability, they are still considered an environmental problem even though the use of most of them has been phased out several decades ago. Soil is a matrix which can retain these contaminants to a great extent. This ability is often associated with the total organic carbon content (TOC). In order to judge the pollution status of soil and to make monitoring data more easily comparable a simple, yet robust extraction method is needed. Agitation solid-liquid-extraction is well suited for this purpose. However, the influence of TOC on the analyte recovery has to be known. For the presented study, 12 organochlorine pesticides and 7 polychlorinated biphenyls were spiked into four model soils with organic carbon contents between 1.6% - 13.3%. The matrices were extracted using solid-liquid extraction between 45 minutes and 16 hours. For comparison, all soils were also extracted using pressurised liquid extraction and Soxhlet extraction. After clean-up the extracts were measured using a gas chromatography-mass spectrometry (GC-MS) system. Statistical analysis of the results implied that the TOC content of the soils did not have significant influence on the extraction efficiency. A longer solid-liquid extraction time did not necessarily increase analyte recovery: Extraction for one hour resulted in 88% recovery while 16 hour extraction led to 89%. Thus, the efficiency of all the methods was comparable for all model soils. Additional investigations regarding GC liner performance highlighted the need for isotopically labelled standards during the analysis of thermolabile pesticides.
KW - POP
KW - Soil organic matter
KW - Solid-liquid-extraction
KW - Pressurised liquid extraction
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-430238
DO - https://doi.org/10.4236/jep.2017.86045
SN - 2152-2219
VL - 08
IS - 06
SP - Article ID:77202, 693
EP - 713
PB - Scientific Research Publishing
AN - OPUS4-43023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hufsky, F.
A1 - Ibrahim, B.
A1 - Beer, M.
A1 - Deng, L.
A1 - Le Mercier, P.
A1 - McMahon, Dino Peter
A1 - Palmarini, M.
A1 - Thiel, V.
A1 - Marz, M.
T1 - Virologists—Heroes need weapons
N2 - Virologists. You might know a couple of them, but unless you are a virologist yourself, the probability that you have collaborated with one in the past is low. The community is relatively small, but they pack a heavy punch and are expected to play a leading role in the research into pathogens that lies ahead. You may ask why we think virologists are our future. Suffice it to say that it is not just because they have invented technologies that belong to the space age, including use of viruses as vehicles to shuttle genes into cells[1], organic nanoparticles with specific tools attached to their surfaces to get inside target cells[2], and using genetically modified viruses as therapies to fight against cancer[3]. Did you know that virologists currently only know of about 3,200 viral species but that more than 320,000 mammal-associated viruses[4] are thought to await discovery? Just think about the viruses hidden in the Arctic ice[5] or in the insects and other animals from once cut-off regions in the world, which now face ever-increasing human exposure[6]. But a heroic (as well as an apocalyptic) role for virologists may also be on the horizon, as the adoption of phage therapy may, in the future, be used to control harmful bacteria when antibiotics fail
KW - Virology
KW - Bioinformatics
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442402
DO - https://doi.org/10.1371/journal.ppat.1006771
SN - 1553-7366
SN - 1553-7374
VL - 14
IS - 2
SP - Article e1006771, 1
EP - 3
PB - Public Library of Science
CY - Lawrence, Kan.
AN - OPUS4-44240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, S.
A1 - De Beats, P.
A1 - Sukumaran, J.
A1 - Mohrbacher, H.
A1 - Woydt, Mathias
A1 - Vleugels, J.
T1 - Effect of carbon content on the microstructure and mechanical properties of NbC-Ni based cermets
N2 - The aim of this work was to correlate the overall carbon contents in NbC-Ni, NbC-Ni-VC and NbC-Ni-Mo starting powders with the resulting microstructure, hardness, and fracture toughness of Ni-bonded NbC cermets.
KW - Niobium carbide
KW - Cermet
KW - Hardmetal
KW - Liquid phase sintering
KW - Carbon
KW - Hardness
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444608
DO - https://doi.org/10.3390/met8030178
SN - 2075-4701
VL - 8
IS - 3
SP - Article 178, 1
EP - 13
PB - MDPI
AN - OPUS4-44460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Örnek, C.
A1 - Léonard, Fabien
A1 - McDonald, S.
A1 - Prajapati, A
A1 - Withers, P. J.
A1 - Engelberg, D.
T1 - Time-dependent in situ measurement of atmospheric corrosion rates of duplex stainless steel wires
N2 - Corrosion rates of strained grade UNS S32202 (2202) and UNS S32205 (2205) duplex stainless steel wires have been measured, in situ, using time-lapse X-ray computed tomography. Exposures to chloride-containing (MgCl2) atmospheric environments at 50 °C (12–15 M Cl− and pH ~5) with different mechanical elastic and elastic/plastic loads were carried out over a period of 21 months. The corrosion rates for grade 2202 increased over time, showing selective dissolution with shallow corrosion sites, coalescing along the surface of the wire. Corrosion rates of grade 2205 decreased over time, showing both selective and pitting corrosion with more localised attack, growing preferentially in depth. The nucleation of stress corrosion cracking was observed in both wires.
KW - X-ray computed tomography
KW - Time-lapse X-ray computed tomography
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444153
UR - https://www.nature.com/articles/s41529-018-0030-9
DO - https://doi.org/10.1038/s41529-018-0030-9
SN - 2397-2106
VL - 2
SP - Article 10, 1
EP - 15
PB - Nature
CY - London
AN - OPUS4-44415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laux, P.
A1 - Tentschert, J.
A1 - Riebeling, Ch.
A1 - Braeuning, A.
A1 - Creutzenberg, O.
A1 - Epp, A.
A1 - Fessard, V.
A1 - Haas, K.-H.
A1 - Haase, A.
A1 - Hund-Rinke, K.
A1 - Jakubowski, Norbert
A1 - Kearns, P.
A1 - Lampen, A.
A1 - Rauscher, H.
A1 - Schoonjans, R.
A1 - Störmer, A.
A1 - Thielmann, A.
A1 - Mühle, U.
A1 - Luch, A.
T1 - Nanomaterials: certain aspects of application, risk assessment and risk communication
N2 - Development and market introduction of new nanomaterials trigger the need for an adequate risk assessment of such products alongside suitable risk communication measures. Current application of classical and new nanomaterials is analyzed in context of regulatory requirements and standardization for chemicals, food and consumer products. The challenges of nanomaterial characterization as the main bottleneck of risk assessment and regulation are presented. In some areas, e.g., quantification of nanomaterials within complex matrices, the establishment and adaptation of analytical techniques such as laser ablation inductively coupled plasma mass spectrometry and others are potentially suited to meet the requirements. As an example, we here provide an approach for the reliable characterization of human exposure to nanomaterials resulting from food packaging. Furthermore, results of nanomaterial toxicity and ecotoxicity testing are discussed, with concluding key criteria such as solubility and fiber rigidity as important parameters to be considered in material development and regulation. Although an analysis of the public opinion has revealed a distinguished rating depending on the particular field of application, a rather positive perception of nanotechnology could be ascertained for the German public in general. An improvement of material characterization in both toxicological testing as well as end-product control was concluded as being the main obstacle to ensure not only safe use of materials, but also wide acceptance of this and any novel technology in the general public.
KW - Nanomaterials
KW - Toxicity
KW - Ecotoxicity
KW - Standardization
KW - Exposure
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-441096
DO - https://doi.org/10.1007/s00204-017-2144-1
VL - 92
IS - 1
SP - 121
EP - 141
PB - Springer
AN - OPUS4-44109
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, S.
A1 - López-Serrano, Ana
A1 - Mitze, H.
A1 - Jakubowski, Norbert
A1 - Schwerdtle, T.
T1 - Single-cell analysis by ICP-MS/MS as a fast tool for cellular bioavailability studies of arsenite
N2 - Single-cell inductively coupled plasma mass spectrometry (SC-ICP-MS) has become a powerful and fast tool to evaluate the elemental composition at a single-cell level. In this study, the cellular bioavailability of arsenite (incubation of 25 and 50 μM for 0-48 h) has been successfully assessed by SC-ICP-MS/MS for the first time directly after re-suspending the cells in water. This procedure avoids the normally arising cell membrane permeabilization caused by cell fixation methods (e.g. methanol fixation). The reliability and feasibility of this SC-ICP-MS/MS approach with a limit of detection of 0.35 fg per cell was validated by conventional bulk ICP-MS/MS analysis after cell digestion and parallel measurement of sulfur and phosphorus.
KW - Single-cell analysis
KW - ICP-MS/MS
KW - Arsenite
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-441105
DO - https://doi.org/10.1039/c7mt00285h
SN - 1756-5901
VL - 10
IS - 1
SP - 73
EP - 76
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-44110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stajanca, Pavol
A1 - Topolniak, Ievgeniia
A1 - Pötschke, Samuel
A1 - Krebber, Katerina
T1 - Solution-mediated cladding doping of commercial polymer optical fibers
N2 - Solution doping of commercial polymethyl methacrylate (PMMA) polymer optical fibers (POFs) is presented as a novel approach for preparation of custom cladding-doped POFs (CD-POFs). The presented method is based on a solution-mediated diffusion of dopant molecules into the fiber cladding upon soaking of POFs in a methanol-dopant solution. The method was tested on three different commercial POFs using Rhodamine B as a fluorescent dopant. The dynamics of the diffusion process was studied in order to optimize the doping procedure in terms of selection of the most suitable POF, doping time and conditions. Using the optimized procedure, longer segment of fluorescent CD-POF was prepared and its performance was characterized. Fiber’s potential for sensing and illumination applications was demonstrated and discussed. The proposed method represents a simple and cheap way for fabrication of custom, short to medium length CD-POFs with various dopants.
KW - Polymer optical fiber
KW - Solution doping
KW - Polymethyl methacrylate
KW - Rhodamine B
KW - Dye-doped fiber
KW - Fluorescent optical fiber
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-441045
DO - https://doi.org/10.1016/j.yofte.2018.02.008
SN - 1068-5200
SN - 1095-9912
VL - 41
SP - 227
EP - 234
PB - Elsevier Inc.
AN - OPUS4-44104
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lasri, J.
A1 - Chulvi, Katherine
A1 - Eltayeb, N. E.
T1 - Crystal structures of (E)-1-naphthaldehyde oxime and (E)-phenanthrene-9-carbaldehyde oxime
N2 - The aldoximes C11H9NO (I) and C15H11NO (II), synthesized in ca 90%yield, by
treatment of 1-naphthaldehyde or phenanthrene-9-carbaldehyde, respectively,
with hydroxylamine hydrochloride and sodium carbonate, have been characterized
by IR, 1H, 13C and DEPT-135 NMR spectroscopies, and also by singlecrystal
X-ray diffraction analysis. The molecules of (I) and (II) are
conformationally similar, with the aldoxime substituent groups lying outside
the planes of the naphthalene or phenanthrene rings, forming dihedral angles
with them of 23.9 (4) and 27.9 (6)°, respectively. The crystal structures of both
(I) and (II) are similar with a single intermolecular O—H...N hydrogenbonding
interaction, giving rise to the formation of one-dimensional polymeric
chains extending along the 21 (b) screw axes in each.
KW - Crystal structure
KW - Aromatic aldehydes
KW - E-aldoximes
KW - Hydrogen bonding
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-443351
DO - https://doi.org/10.1107/S2056989018002116
SN - 2056-9890
VL - 74
SP - 332
EP - 336
PB - International Union of Crystallography
CY - Chester
AN - OPUS4-44335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hollamby, M. J.
A1 - Smith, C. F.
A1 - Britton, M. M.
A1 - Danks, A. E.
A1 - Schnepp, Z.
A1 - Grillo, I.
A1 - Pauw, Brian Richard
A1 - Kishimura, A.
A1 - Nakanishi, T.
T1 - The aggregation of an alkyl–C60 derivative as a function of concentration, temperature and solvent type
N2 - Contrast-variation small-angle neutron scattering (CV-SANS), small-angle X-ray scattering (SAXS), nuclear magnetic resonance (NMR) measurements of diffusion and isothermal titration calorimetry (ITC) are used to gain insight into the aggregation of an alkyl–C60 derivative, molecule 1, in n-hexane, n-decane and toluene as a function of concentration and temperature. Results point to an associative mechanism of aggregation similar to other commonly associating molecules, including non-ionic surfactants or asphaltenes in non-aqueous solvents. Little aggregation is detected in toluene, but small micelle-like structures form in n-alkane solvents, which have a C60-rich core and alkyl-rich shell. The greatest aggregation extent is found in n-hexane, and at 0.1 M the micelles of 1 comprise around 6 molecules at 25 °C. These micelles become smaller when the concentration is lowered, or if the solvent is changed to n-decane. The solution structure is also affected by temperature, with a slightly larger aggregation extent at 10 °C than at 25 °C. At higher concentrations, for example in solutions of 1 above 0.3 M in n-decane, a bicontinuous network becomes apparent. Overall, these findings aid our understanding of the factors driving the assembly of alkyl–π-conjugated hydrophobic amphiphiles such as 1 in solution and thereby represent a step towards the ultimate goal of exploiting this phenomenon to form materials with well-defined order.
KW - Complex Molecular Systems
KW - Supramolecules
KW - Scattering
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442977
DO - https://doi.org/10.1039/C7CP06348B
VL - 20
IS - 5
SP - 3773
EP - 3380
PB - RSC
AN - OPUS4-44297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkelmann, Aimo
A1 - Nolze, Gert
A1 - Vespucci, S.
A1 - Gunsekar, N.-K.
A1 - Trager-Cowan, C.
A1 - Vilalta-Clemente, A.
A1 - Wilkinson, A. J.
A1 - Voss, M.
T1 - Diffraction effects and inelastic electron transport in angle-resolved microscopic imaging applications
N2 - We analyse the signal formation process for scanning electron microscopic imaging applications on crystalline specimens. In accordance with previous investigations, we find nontrivial effects of incident beam diffraction on the backscattered electron distribution in energy and momentum. Specifically, incident beam diffraction causes angular changes of the backscattered electron distribution which we identify as the dominant mechanism underlying pseudocolour orientation imaging using multiple, angle-resolving detectors. Consequently, diffraction effects of the incident beam and their impact on the subsequent coherent and incoherent electron transport need to be taken into account for an in-depth theoretical modelling of the energy- and momentum distribution of electrons backscattered from crystalline sample regions. Our findings have implications for the level of theoretical detail that can be necessary for the interpretation of complex imaging modalities such as electron channelling contrast imaging (ECCI) of defects in crystals. If the solid angle of detection is limited to specific regions of the backscattered electron momentum distribution, the image contrast that is observed in ECCI and similar applications can be strongly affected by incident beam diffraction and topographic effects from the sample surface. As an application, we demonstrate characteristic changes in the resulting images if different properties of the backscattered electron distribution are used for the analysis of a GaN thin film sample containing dislocations.
KW - EBSD
KW - Channeling-in
KW - Background processing
KW - Center of mass
KW - Backscattered electrons
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422063
DO - https://doi.org/10.1111/jmi.12571
SN - 0022-2720
VL - 267
IS - 3
SP - 330
EP - 346
PB - Wiley & Sons, Ltd.
AN - OPUS4-42206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rudenko, A.
A1 - Colombier, J.-P.
A1 - Höhm, S.
A1 - Rosenfeld, A.
A1 - Krüger, Jörg
A1 - Bonse, Jörn
A1 - Itina, T.E.
T1 - Spontaneous periodic ordering on the surface and in the bulk of dielectrics irradiated by ultrafast laser: a shared electromagnetic origin
N2 - Periodic self-organization of matter beyond the diffraction limit is a puzzling phenomenon, typical both for surface and bulk ultrashort laser processing. Here we compare the mechanisms of periodic nanostructure formation on the surface and in the bulk of fused silica. We show that volume nanogratings and surface nanoripples having subwavelength periodicity and oriented perpendicular to the laser polarization share the same electromagnetic origin. The nanostructure orientation is defined by the near-field local enhancement in the vicinity of the inhomogeneous scattering centers. The periodicity is attributed to the coherent superposition of the waves scattered at inhomogeneities. Numerical calculations also support the multipulse accumulation nature of nanogratings formation on the surface and inside fused silica. Laser surface processing by multiple laser pulses promotes the transition from the high spatial frequency perpendicularly oriented nanoripples to the low spatial frequency ripples, parallel or perpendicular to the laser polarization. The latter structures also share the electromagnetic origin, but are related to the incident field interference with the scattered far-field of rough non-metallic or transiently metallic surfaces. The characteristic ripple appearances are predicted by combined electromagnetic and thermo-mechanical approaches and supported by SEM images of the final surface morphology and by time-resolved pump-probe diffraction measurements.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser
KW - Nanostructures
KW - Dielectrics
KW - Electromagnetic scattering
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-421747
UR - https://www.nature.com/articles/s41598-017-12502-4
DO - https://doi.org/10.1038/s41598-017-12502-4
SN - 2045-2322
VL - 7
SP - Article 12306, 1
EP - 14
PB - Springer Nature
AN - OPUS4-42174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hinrichs, R.
A1 - Zen Vasconcellos, M.A.
A1 - Österle, Werner
A1 - Prietzel, C.
T1 - Amorphization of graphite flakes in gray cast iron under tribological load
N2 - A gray cast iron disc, which had been submitted to a heavy duty automotive brake test, was examined with energy filtered transmission electron microscopy. A graphite flake in a convenient angular position showed the shear interaction of graphite layers with the iron matrix in nano-scale resolution. Atomic layers of graphite were wedged into the ferritic bulk, allowing the entrance of oxygen and the subsequent formation of magnetite. The exfoliated few-layer graphene batches deformed heavily when forced into the matrix. When Raman spectra from the disc surface, which show distinctive carbonaceous bands, were compared with Raman spectra from graphite subjected to deformation in a shaker mill with different milling times, it could be seen that the shear stress on the brake surface was much more effective to induce disorder than the milling, where compressive and impact forces had been additionally exerted on the sample. During shear load the high anisotropy of elastic modulus in the graphite crystalline structure and the low adhesion between graphite basal planes allowed the exfoliation of wrinkled few-layer grapheme batches, causing the formation of more defect related Raman bands than the mechanical stress during high-energy milling.
KW - Graphite
KW - Shear load
KW - Amorphization
KW - EFTEM
KW - Raman spectroscopy
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469227
DO - https://doi.org/10.1590/1980-5373-MR-2017-1000
SN - 1516-1439
SN - 1980-5373
VL - 21
IS - 4
SP - e20171000, 1
EP - 6
PB - Universidade Federal de São Carlos
CY - São Carlos
AN - OPUS4-46922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wack, Yannick
A1 - Heckel, Thomas
A1 - Boehm, Rainer
A1 - Brackrock, Daniel
T1 - Simulation der Schallausbreitung in Eisenbahnschienen mit FEM und SAM
N2 - Die Simulation von Ultraschallausbreitung ist ein wesentliches Hilfsmittel zur Optimierung von Prüfanordnungen und wird zunehmend in der Prüfvorbereitung eingesetzt. Eisenbahnschienen sind Bauteile mit komplexer Geometrie und im eingebauten Zustand eingeschränkter Zugänglichkeit. Bei der Prüfung im Feld entstehen aus der Schienengeometrie komplexe Echosignale mit Formanzeigen, die schwer zu interpretieren sind.
Für das bessere Verständnis der Schallausbreitung in der Eisenbahnschiene wird diese in einem ersten Schritt mit Hilfe verschiedener Ansätze modelliert. Hierbei werden Finite Elemente Methoden und semi-analytischen Modelle verwendet. In einem zweiten Schritt werden die Ergebnisse der Simulationsmodelle einander gegenübergestellt und mit Messungen an realen Schienen verglichen.
Ziel dieser Untersuchungen ist die Validierung von Simulationsverfahren mit Hilfe von Messdatensätzen und Überprüfung der Anwendbarkeit bei der Bewertung von Ergebnissen der Schienenprüfung.
T2 - DGZfP-Jahrestagung 2018
CY - Leibzig, Gemany
DA - 07.05.2018
KW - Ultraschall
KW - FEM
KW - Eisenbahn
KW - Simulation
KW - SAM
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474585
SP - Poster 4 - 1
EP - 5
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-47458
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zeise, I.
A1 - Heiner, Z.
A1 - Holz, S.
A1 - Joester, Maike
A1 - Buttner, C.
A1 - Kneipp, Janina
T1 - Raman imaging of plant cell walls in sections of cucumis sativus
N2 - Raman microspectra combine information on chemical composition of plant tissues with spatial information. The contributions from the building blocks of the cell walls in the Raman spectra of plant tissues can vary in the microscopic sub-structures of the tissue. Here, we discuss the analysis of 55 Raman maps of root, stem, and leaf tissues of Cucumis sativus, using different spectral contributions from cellulose and lignin in both univariate and multivariate imaging methods. Imaging based on hierarchical cluster analysis (HCA) and principal component analysis (PCA) indicates different substructures in the xylem cell walls of the different tissues. Using specific signals from the cell wall spectra, analysis of the whole set of different tissue sections based on the Raman images reveals differences in xylem tissue morphology. Due to the specifics of excitation of the Raman spectra in the visible wavelength range (532 nm), which is, e.g., in resonance with carotenoid species, effects of photobleaching and the possibility of exploiting depletion difference spectra for molecular characterization in Raman imaging of plants are discussed. The reported results provide both, specific information on the molecular composition of cucumber tissue Raman spectra, and general directions for future imaging studies in plant tissues.
KW - Raman
KW - Imaging
KW - Pants
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474610
DO - https://doi.org/10.3390/plants7010007
SN - 2223-7747
VL - 7
IS - 1
SP - 7, 1
EP - 16
PB - MDPI, ST ALBAN-ANLAGE 66, CH-4052 BASEL, SWITZERLAND
AN - OPUS4-47461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rohn, H.
A1 - Simon, Franz-Georg
A1 - Schmidt, M.
A1 - Giegrich, J.
A1 - Oberender, C.
A1 - Denz, W.
A1 - Niebaum, A.
ED - Ludwig, C.
ED - Matasci, C.
T1 - The Guideline Series VDI 4800 Resource Efficiency: An Approach for Increasing Resource Efficiency with Aim of Conservation of Natural Resources in the Industrial Sector
N2 - In 2011, the Association of German Engineers (VDI) started working on a set of guidelines
towards increased resource efficiency. These guidelines represent a framework that defines resource efficiency and outlines considerations for the producing industry. A special guideline for SMEs is included as well as guidelines on methodologies for evaluating resource use
indicators, such as the cumulative raw material demand of products and production systems.
Resource efficiency, defined here as the relationship between a specific benefit or use and the natural resources that need to be spent or consumed to attain this benefit or use. It can be
evaluated by defining a function which expresses the specific benefit and quantifies the resource requirements through a set of indicators (use of raw materials, energy, water, land
and ecosystem services including sinks). The results from this also depend on the system boundary parameters and the allocation rules for by-products and waste treatment options. Optimising resource use is possible at all stages of a product’s or production system’s life cycle chain (raw material extraction, production and manufacturing, use and consumption, and the
end-of-life stage).
VDI guidelines are widely accepted across Germany’s industrial sector and therefore represent an important means of mainstreaming resource efficiency in this target area. As well as providing a methodological framework, the guidelines describe strategies and measures towards increasing resource efficiency, and they enable industrial producers and service providers to identify potential areas of improvement. The full article presents an overview of
the methodology and contents of these guidelines and discusses their impact in achieving absolute reductions in the industrial use of natural resources.
KW - Resource efficiency
KW - Life cycle thinking
KW - Products and production systems
KW - Standardization
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-426443
UR - https://www.wrforum.org/wrfpublicationspdf/boosting-resource-productivity/
SN - 978-3-9521409-7-0
SP - 125
EP - 132
PB - Paul Scherrer Institute
CY - Villigen PSI, Switzerland
ET - 1
AN - OPUS4-42644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gehrmann, H.-J.
A1 - Hiebel, M.
A1 - Simon, Franz-Georg
T1 - Methods for the Evaluation of Waste Treatment Processes
N2 - Decision makers for waste management are confronted with the problem of selecting the most economic, environmental, and socially acceptable waste treatment process. This paper elucidates evaluation methods for waste treatment processes for the comparison of ecological and economic aspects such as material flow analysis, statistical entropy analysis, energetic and exergetic assessment, cumulative energy demand, and life cycle assessment.The work is based on the VDI guideline 3925. A comparison of two thermal waste treatment plants with different process designs and energy recovery systems was performed with the described evaluation methods. The results are mainly influenced by the type of energy recovery, where the waste-to-energy plant providing district heat and process steam emerged to be beneficial in most aspects. Material recovery options from waste incineration were evaluated according to sustainability targets, such as saving of resources and environmental protection.
KW - Material flow analysis
KW - Life cycle assessment
KW - Cumulative energy demand
KW - Cost benefit analysis
KW - Eco-efficiency analysis
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-426455
UR - https://www.hindawi.com/journals/je/2017/3567865/
DO - https://doi.org/10.1155/2017/3567865
SN - 2314-4912
VL - 2017
SP - Article ID 3567865-1
EP - 13
PB - Hindawi
CY - London
AN - OPUS4-42645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trimpert, J.
A1 - Groenke, N.
A1 - Jenckel, M.
A1 - He, Shulin
A1 - Kunec, D.
A1 - Szpara, M.L.
A1 - Spatz, S.J.
A1 - Osterrieder, N.
A1 - McMahon, Dino Peter
T1 - A phylogenomic analysis of Marek's disease virus (MDV) reveals independent paths to virulence in Eurasia and North America
N2 - Virulence determines the impact a pathogen has on the fitness of its host, yet current understanding of the evolutionary origins and causes of virulence of many pathogens is surprisingly incomplete. Here, we explore the evolution of Marek’s disease virus (MDV), a herpesvirus commonly afflicting chickens and rarely other avian species. The history of MDV in the 20th century represents an important case study in the evolution of virulence. The severity of MDV infection in chickens has been rising steadily since the adoption of intensive farming techniques and vaccination programs in the 1950s and 1970s, respectively. It has remained uncertain, however, which of these factors is causally more responsible for the observed increase in virulence of circulating viruses. We conducted a phylogenomic study to understand the evolution of MDV in the context of dramatic changes to poultry farming and disease control. Our analysis reveals evidence of geographical structuring of MDV strains, with reconstructions supporting the emergence of virulent viruses independently in North America and Eurasia. Of note, the emergence of virulent viruses appears to coincide approximately with the introduction of comprehensive vaccination on both continents. The time-dated phylogeny also indicated that MDV has a mean evolutionary rate of ~1.6 × 10−5 substitutions per site per year. An examination of gene-linked mutations did not identify a strong association between mutational variation and virulence phenotypes, indicating that MDV may evolve readily and rapidly under strong selective pressures and that multiple genotypic pathways may underlie virulence adaptation in MDV.
KW - Sesistance
KW - Disease
KW - Emergence
KW - Evolution
KW - Virulence
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429054
DO - https://doi.org/10.1111/eva.12515
SN - 1752-4571
VL - 10
IS - 10
SP - 1091
EP - 1101
PB - John Wiley & Sons Ltd.
AN - OPUS4-42905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - De la Rosa, J. M.
A1 - Martin-Sanchez, Pedro Maria
A1 - Santiago-Cortes, S.
A1 - Hermosin, B.
A1 - Knicker, H.
A1 - Saiz-Jimenez, C.
ED - De la Rosa, J. M.
T1 - Structure of melanins from the fungi Ochroconis lascauxensis and Ochroconis anomala contaminating rock art in the Lascaux Cave
N2 - Two novel species of the fungal genus Ochroconis, O. lascauxensis and O. anomala have been isolated from the walls of the Lascaux Cave, France. The interest in these fungi and their melanins lies in the formation of black stains on the walls and rock art which threatens the integrity of the paintings. Here we report solid-state cross polarization magic-angle spinning 13C and 15N nuclear magnetic resonance (NMR) spectroscopy and surface-enhanced Raman spectroscopy (SERS) of the melanins extracted from the mycelia of O. lascauxensis and O. anomala in order to known their chemical structure. The melanins from these two species were compared with those from other fungi. The melanins from the Ochroconis species have similar SERS and 13C and 15N NMR spectra. Their chemical structures as suggested by the data are not related to 3,4-dihydroxyphenylalanine, 5,6-dihydroxyindole or 1,8-dihydroxynaphthalene precursors and likely the building blocks from the melanins have to be based on other phenols that react with the N-terminal amino acid of proteins. The analytical pyrolysis of the acid hydrolysed melanin from O. lascauxensis supports this assumption.
KW - Microbiology
KW - Biodeterioration
KW - Melanins
KW - Fungi
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435345
DO - https://doi.org/10.1038/s41598-017-13862-7
SN - 2045-2322
VL - 7
SP - 13441, 1
EP - 13441, 11
PB - Nature
AN - OPUS4-43534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Kern, Simon
A1 - Guhl, Svetlana
A1 - Meyer, Klas
A1 - Maiwald, Michael
ED - Maiwald, Michael
T1 - Validation report on NMR
N2 - The departure from the current automation landscape to next generation automation concepts for the process industry has already begun. Smart functions of sensors simplify their use and enable plug and play integration, even though they may appear to be more complex at first sight. Smart sensors enable concepts like self-diagnostics, self-calibration, and self-configuration/ parameterization whenever our current automation landscape allows it.
Here we summarize the currently discussed general requirements for process sensors 4.0 and introduce a smart online NMR sensor module as example, which was developed for an intensified industrial process funded by the EU’s Horizon 2020 research and innovation programme (www.consensspire.eu).
KW - Process Monitoring
KW - Online NMR Spectroscopy
KW - Indirect Hard Modeling
KW - Process Control
KW - Process Analytical Technology
KW - CONSENS
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435521
SP - 1
EP - 31
AN - OPUS4-43552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Recknagel, Sebastian
A1 - Scharf, Holger
A1 - Lkhagvasuren, B.
A1 - Oyuntungalag, U.
A1 - Rausch, J.
T1 - Certified reference material for determination of total cyanide in soil [BAM-U116/CGL306]
N2 - CRM (Certified Reference Material) BAM-U116/CGL306 “Cyanide in soil” was produced within a framework of cooperation between CGL (Central Geological Laboratory) of Mongolia and Federal Institute for Materials Research and Testing (BAM) of Germany in 2013-2017. The CRM BAM-U116/CGL306 represents a mixture of a sandy soil collected from a contaminated former gasworks area in the Berlin region (Germany) and an unpolluted sandy soil from Nalaikh region (Mongolia).
The bulk candidate material for this reference material was prepared at CGL CRM Laboratory exclusively destined to the preparation of reference materials and equipped with modern technical equipment. Homogeneity, stability and shelf life were studied in full compliance with ISO Guide 35. The CRM was evaluated as sufficiently homogeneous. Statistical evaluation of certification analysis
was software packages SoftCRM and ProLab Plus. Certified value of total cyanide of the CRM is 12.0 mg/kg and expanded uncertainty was assigned as 0.8 mg/kg. The intended purpose of this material is the verification of analytical results obtained for the mass fraction of total cyanide in soils and soil-like materials applying the standardized procedure ISO 11262:2011. As any reference material, it can also be used for routine performance checks (quality control charts) or validation studies.
KW - CRM
KW - Cyanide in soil
KW - Total cyanide
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469694
DO - https://doi.org/10.17265/2162-5263/2018.04.004
SP - 149
EP - 161
PB - David Publishing
AN - OPUS4-46969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ringleb, F.
A1 - Andree, Stefan
A1 - Heidmann, B.
A1 - Bonse, Jörn
A1 - Eylers, K.
A1 - Ernst, O.
A1 - Boeck, T.
A1 - Schmid, M.
A1 - Krüger, Jörg
T1 - Femtosecond laser-assisted fabrication of chalcopyrite micro-concentrator photovoltaics
N2 - Micro-concentrator solar cells offer an attractive way to further enhance the efficiency of planar-cell technologies while saving absorber material. Here, two laser-based bottom-up processes for the fabrication of regular arrays of CuInSe2 and Cu(In,Ga)Se2 microabsorber islands are presented, namely one approach based on nucleation and one based on laser-induced forward transfer.
Additionally, a procedure for processing these microabsorbers to functioning micro solar cells connected in parallel is demonstrated. The resulting cells show up to 2.9% efficiency and a significant efficiency enhancement under concentrated Illumination.
KW - Chalcopyrite
KW - Femtosecond laser patterning
KW - Laser-induced forward transfer
KW - Micro-concentrator solar cell
KW - Photovoltaics
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470026
DO - https://doi.org/10.3762/bjnano.9.281
SN - 2190-4286
VL - 9
SP - 3025
EP - 3038
PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften
CY - Frankfurt, M.
AN - OPUS4-47002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waske, Anja
A1 - Dutta, B.
A1 - Teichert, N.
A1 - Weise, B.
A1 - Shayanfar, N.
A1 - Becker, A.
A1 - Hütten, A.
A1 - Hickel, T.
T1 - Coupling Phenomena in Magnetocaloric Materials
N2 - Strong coupling effects in magnetocaloric materials are the key factor to achieve a large magnetic entropy change. Combining insights from experiments and ab initio calculations, we review relevant coupling phenomena, including atomic coupling, stress coupling, and magnetostatic coupling. For the investigations on atomic coupling, we have used Heusler compounds as a flexible model system. Stress coupling occurs in first‐order magnetocaloric materials, which exhibit a structural transformation or volume change together with the magnetic transition. Magnetostatic coupling has been experimentally demonstrated in magnetocaloric particles and fragment ensembles. Based on the achieved insights, we have demonstrated that the materials properties can be tailored to achieve optimized magnetocaloric performance for cooling applications.
KW - Ab initio calculations
KW - Magneto-structural transition
KW - Magnetocaloric materials
KW - Ferroic cooling
KW - Heusler alloys
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473045
DO - https://doi.org/10.1002/ente.201800163
VL - 6
IS - 8
SP - 1429
EP - 1447
PB - Wiley
AN - OPUS4-47304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ewert, Uwe
A1 - Zscherpel, Uwe
A1 - Vogel, Justus
A1 - Zhang, F.
A1 - Long, N.X.
A1 - Nguyen, T.P.
T1 - Visibility of Image Quality Indicators (IQI) by Human Observers in Digital Radiography in Dependence on Measured MTFs and Noise Power Spectra
N2 - Digital radiographic images were analysed to predict the visibility of image quality indicators (IQI), based on normalized noise power spectra (NNPP) and modulation transfer function (MTF) measurements. The fixed pattern noise of some digital detectors result in different noise spectra, which influence the visibility of different IQIs, depending on the hole diameter. Studies, based on measurement of basic spatial resolution and contrast to noise ratio were performed together with presampled MTF measurements and the NNPS in dependence on the spatial frequency. Plate hole IQIs, step hole IQIs, and equivalent penetrameter sensitivity (EPS) IQIs based on ASTM E 746 were measured to verify the influence of the different parameters. Modelling of digital images was used to verify the applied numeric tools. A study has been performed for imaging plates and digital detector arrays to analyse differences. Formulas for the prediction of the visibility functions for hole type IQIs are derived. In consequence the standards for characterization and classification of computed radiography (ASTM E 2446) and radiography with DDAs (ASTM E 2597) need to be revised.
T2 - 12th ECNDT 2018
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - Image evaluation
KW - Computed radiography (CR)
KW - Digital Detector Array (DDA)
KW - Detail detection
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473486
UR - www.ndt.net/?id=22967
SN - 1435-4934
VL - 23
IS - 8
SP - 1
EP - 7
PB - NDT.net
CY - Kirchwald
AN - OPUS4-47348
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ewert, Uwe
A1 - Zscherpel, Uwe
A1 - Zhang, F.
A1 - Long, N.X.
A1 - Phong, N.
T1 - Essentielle Parameter zur numerischen Abschätzung der Sichtbarkeit von Bildgüteprüfkörpern in der digitalen Radiographie
N2 - Die Voraussetzungen für die Vorhersage der Sichtbarkeit von Bildgüteprüfkörpern (BPK) wurden seit Beginn der kommerziellen Anwendung der technischen Radiographie diskutiert und in diversen nationalen und internationalen Standards festgeschrieben. Diese Fragen werden nach Einführung der digitalen Radiographie und der CT wieder neu diskutiert. Draht BPKs wurden in Deutschland seit 1935 (DIN 1915: 1935) und später in den meisten europäischen Ländern benutzt. In den USA und Frankreich wurden vorzugsweise BPKs mit Löchern verwendet (ASTM E 1025 seit 1984 oder E 1742 seit 1992 bzw. die Vorgängernorm MIL STD-543 seit 1962). Jetzt werden auch die Umrechnungsnormen zur Erkennbarkeit von Draht zu Loch-BPKs in Frage gestellt. ISO 19232-3, der französische RCCM-Kode einerseits und ASTM E 747 und ASME BPVC Section V Tab. T-276 andererseits unterscheiden sich erheblich bei den Anforderungen im Bereich hoher Wandstärken (Hochenergieradiographie). Untersuchungen dazu werden vorgestellt. Mit Einführung der digitalen Detektoren ändern sich auch die Rauschspektren. Durch die Herstellung werden insbesondere bei Speicherfolien "Rauschmuster" eingeprägt, die bei hohen Belichtungsdosen sichtbar werden. Diese veränderten Rauschspektren ergeben auch veränderte Erkennungsparameter für menschliche Bildauswerter. Hierzu wurden an ausgewählten Detektoren MTFs (presampled) und normierte Rauschspektren gemessen. Erweiterte Erkennbarkeits-Formeln zur Vorhersage der Sichtbarkeit von BPKs für Bildauswerter und erste Ergebnisse werden vorgestellt.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Image quality
KW - Computed radiography (CR)
KW - Digital Detector Array (DDA),
KW - Sichtbarkeit von Anzeigen
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473496
UR - www.ndt.net/?id=23069
VL - 2018
SP - 1
EP - 14
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-47349
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brückner, B.
A1 - Zscherpel, Uwe
T1 - Spektroskopie gepulster Röntgenquellen
N2 - Spektren von gepulsten Röntgenquellen wie Blitzröhren, Linearbeschleuniger (LINACs) oder Betatrons lassen sich in der Literatur nicht finden. Eine gängige Lehrmeinung ist, dass sich solche Spektren nicht messen lassen. Deshalb wurden in Zusammenarbeit mit der Goethe-Universität Frankfurt und neuester Messtechnik diese Problematik untersucht. Es wurde ein CeBr3-Szintillator-Kristall mit einem klassischen Photoelektronenvervielfacher (PMT) und einer analogen Übertragungskette verwendet, der über Stunden Integrationszeit nur einen sehr geringen Untergrund detektiert. Als kritischter Punkt stellte sich die geeignete Kollimierung von Quelle und Detektor bei möglichst großem Abstand heraus. Zu diesem Zweck wurde das verwendete 7 MeV-Betatron in einen 3t-Bleibunker betrieben, der ein Austrittsloch von 1 mm für die erzeugte Röntgenstrahlung besaß. Der Detektor wurde mit einem Densimet-Zylinder abgeschirmt. Damit konnte die Bedingung für die Spektroskopie gepulster Quellen erreicht werden: pro Puls darf nur 1 Photon den Detektorkristall erreichen, damit ohne Pile-up seine Energie vermessen werden kann. Trotz schnellster Elektronik war es nicht möglich, mehere Photonen pro Röntgenpuls (beim Betatron ca. 1 Mikrosekunde) spektral richtig aufzulösen. Die gemessenen Spektren zeigen die erwartete Form, wie sie z.B. mit aRTist simuliert werden können.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Spektroskopie
KW - Betatron
KW - Röntgenblitzröhre
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473505
SP - 1
EP - 2
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-47350
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chandra, K.
A1 - Kranzmann, Axel
T1 - High temperature oxidation of 9–12% Cr ferritic/martensitic steels under dual-environment conditions
N2 - In normal operations, the opposite surfaces of the power plant components are exposed to two different environments, i.e. air/flue gas on the one side and steam on the other side. Exposure under such dual-environment can lead to accelerated corrosion of the components on the air side. The oxidation behaviour of ferritic/martensitic steel T92 was investigated under dual-environment in a specially designed test equipment. The samples were exposed to dry oxyfuel flue gas (CO2–27%N2–2%O2–1%SO2) on one side and to steam on the other side up to 1000 h at 650°C. The formation of oxide scales was characterised by optical microscopy and scanning electron microscopy with attached energy-dispersive spectroscopy. Oxidation rate of specimens under dual-Environment condition was almost three times higher than that in single-environment condition. This is explained based on hydrogen transport through the bulk alloy from the steam side to the flue gas side.
KW - Oxidation
KW - Dual-environment
KW - Oxyfuel
KW - Ferritic/martensitic steel
KW - Steam
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457101
DO - https://doi.org/10.1080/1478422X.2017.1374049
VL - 53
IS - 31
SP - 27
EP - 33
PB - Taylor & Francis
AN - OPUS4-45710
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schreier, Andy
A1 - Wosniok, Aleksander
A1 - Liehr, Sascha
A1 - Krebber, Katerina
T1 - Humidity-induced Brillouin frequency shift in perfluorinated polymer optical fibers
N2 - We report, to our knowledge, for the first time on humidity-induced Brillouin frequency shifts in perfluorinated graded index polymer optical fibers. A linear relation between Brillouin frequency shift and humidity was observed. Furthermore, the humidity coefficient of the Brillouin frequency shift is demonstrated to be a function of temperature (-107 to -64 kHz/%r.h. or -426 to -49 kHz m3/g in the range of 20 to 60 °C). An analytical description proves temperature and humidity as two mutually independent effects on the Brillouin frequency shift.
KW - Brillouin
KW - Polymer optical fibre
KW - Humidity
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457165
DO - https://doi.org/10.1364/OE.26.022307
SN - 1094-4087
VL - 26
IS - 17
SP - 22307
EP - 22314
PB - Optical Society of America
AN - OPUS4-45716
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Otremba, Frank
A1 - Romero-Navarrete, José A.
A1 - Lozano Guzmán, A. A.
T1 - Modelling of a Partially Loaded Road Tanker during a Braking-in-a-Turn Maneuver
N2 - This paper describes a theoretical model to simulate the effects of a sloshing cargo on the safety performance of a vehicle that performs a braking-in-a-turn maneuver when travels at a partial fill level. The fundamental assumption of the model consists of the superposition of the effects of two simplified mechanical-analogy models that represent a liquid cargo on a vehicle, including one for the roll motion and another one for the pitch motion. The distinctive characteristics of the mechanical models, however, is that they are based upon a validated formulation to establish the properties of the pendulum (length).
The results suggest a small effect of the sloshing cargo on the braking efficiency of the cargo, while the load transfer is moderately affected. However, such results should be put into a perspective, according to which such small variations can represent the avoidance of a rear-end crash or a rollover. In this respect, a specialized ABS system could be considered to improve the performance of such kind of vehicles when performing such maneuvers.
Validation of the proposed methodology should be performed as a continuation of this research effort.
KW - ABS
KW - Braking-in-a-turn maneuver
KW - Cargo sloshing
KW - Road tankers
KW - Load transfer
KW - Simulation
KW - Turning maneuvers
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456908
DO - https://doi.org/10.3390/act7030045
VL - 7
IS - 45
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-45690
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Davis, Hannah E.
A1 - Meconcelli, Stefania
A1 - Radek, R.
A1 - McMahon, Dino Peter
T1 - Termites shape their collective behavioural response based on stage of infection
N2 - Social insects employ a range of behaviours to protect their colonies against disease, but little is known about how such collective behaviours are orchestrated. This is especially true for the social Blattodea (termites). We developed an experimental approach that allowed us to explore how the social response to disease is co-ordinated by multistep host-pathogen interactions. We infected the eastern subterranean termite Reticulitermes flavipes with the entomopathogenic fungus Metarhizium anisopliae, and then, at different stages of infection, reintroduced them to healthy nestmates and recorded behavioural responses. As expected, termites groomed pathogen-exposed individuals significantly more than controls; however, grooming was significantly elevated after fungal germination than before, demonstrating the importance of fungal status to hygienic behaviour. Significantly, we found that cannibalism became prevalent only after exposed termites became visibly ill, highlighting the importance of host condition as a cue for social hygienic behaviour. Our study reveals the presence of a coordinated social response to disease that depends on stage of infection. Specifically, we show how the host may play a key role in triggering its own sacrifice. Sacrificial self-flagging has been observed in other social insects: our results demonstrate that termites have independently evolved to both recognize and destructively respond to sickness.
KW - Social
KW - Immunity
KW - Cannibalism
KW - Entomopathogen
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-463239
DO - https://doi.org/10.1038/s41598-018-32721-7
SN - 2045-2322
VL - 8
SP - 14433, 1
EP - 10
PB - Nature
CY - London
AN - OPUS4-46323
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bertovic, Marija
T1 - Assessing and Treating Risks in Mechanised NDT: A Human Factors Study
N2 - Reliability of NDT is affected by human factors, which have thus far received the least amount of attention in the reliability assessments. With increased use of automation, in terms of mechanised testing (automation-assisted inspection and the corresponding evaluation of data), higher reliability standards are believed to have been achieved. However, human inspectors, and thus human factors, still play an important role throughout this process and the risks involved in this application are unknown. The aim of this study was to explore for the first time the risks associated with mechanised NDT and find ways of mitigating their effects on the inspection performance. Hence, the objectives were to identify and Analyse potential risks in mechanised NDT and devise measures against them. To address those objectives, a risk assessment in form of a Failure Modes and Effects Analysis (FMEA) was conducted. This analysis revealed potential for failure during both the acquisition and evaluation of NDT data that could be assigned to human, technology, and organisation. Since the existing preventive measures were judged to be insufficient to defend the system from identified failures, new preventive measures were suggested.
KW - NDT
KW - Human factors
KW - Risk assessment
KW - FMEA
KW - Reliability
KW - Human error
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-463325
SN - 1616-069X
IS - 161
SP - 52
EP - 62
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-46332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ibrahim, B.
A1 - Arkhipova, K.
A1 - Andeweg, A.C.
A1 - Posada-Céspedes, S.
A1 - Enault, F.
A1 - Gruber, A.
A1 - Koonin, E.V.
A1 - Kupczok, A.
A1 - Lemey, P.
A1 - McHardy, A.C.
A1 - McMahon, Dino Peter
A1 - Pickett, B.E.
A1 - Robertson, D.L.
A1 - Scheuermann, R.H.
A1 - Zhernakova, A.
A1 - Zwart, M.P.
A1 - Schönhuth, A.
A1 - Dutilh, B.E.
A1 - Marz, M.
T1 - Bioinformatics meets virology: The European virus bioinformatics center's second annual meeting
N2 - The Second Annual Meeting of the European Virus Bioinformatics Center (EVBC), held in Utrecht, Netherlands, focused on computational approaches in virology, with topics including (but not limited to) virus discovery, diagnostics, (meta-)genomics, modeling, epidemiology, molecular structure, evolution, and viral ecology. The goals of the Second Annual Meeting were threefold: (i) to bring together virologists and bioinformaticians from across the academic, industrial, professional, and training sectors to share best practice; (ii) to provide a meaningful and interactive scientific environment to promote discussion and collaboration between students, postdoctoral fellows, and both new and established investigators; (iii) to inspire and suggest new research directions and questions. Approximately 120 researchers from around the world attended the Second Annual Meeting of the EVBC this year, including 15 renowned international speakers. This report presents an overview of new developments and novel research findings that emerged during the meeting.
KW - Bioinformatics
KW - Software
KW - Virology
KW - Viruses
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458814
DO - https://doi.org/10.3390/v10050256
SN - 1999-4915
VL - 10
IS - 5
SP - 256, 1
EP - 19
PB - MDPI
AN - OPUS4-45881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waske, Anja
A1 - Dutta, B.
A1 - Teichert, N.
A1 - Weise, B.
A1 - Shayanfar, N.
A1 - Becker, A.
A1 - Hütten, A.
A1 - Hickel, T.
T1 - Coupling Phenomena in Magnetocaloric Materials
N2 - Strong coupling effects in magnetocaloric materials are the key factor to achieve a large magnetic entropy change. Combining insights from experiments and ab initio calculations, we review relevant coupling phenomena, including atomic coupling, stress coupling, and magnetostatic coupling. For the investigations on atomic coupling, we have used Heusler compounds as a flexible model system. Stress coupling occurs in first‐order magnetocaloric materials, which exhibit a structural transformation or volume change together with the magnetic transition. Magnetostatic coupling has been experimentally demonstrated in magnetocaloric particles and fragment ensembles. Based on the achieved insights, we have demonstrated that the materials properties can be tailored to achieve optimized magnetocaloric performance for cooling applications.
KW - Epitaxial thin films
KW - Coupling
KW - Atomic Scale
KW - Stoichiometric phases
KW - Multilaysers
KW - Stress Coupling
KW - Surface defects
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458856
DO - https://doi.org/10.1002/ente.201800163
VL - 6
IS - 8
SP - 1429
EP - 1447
PB - Wiley-VCH
AN - OPUS4-45885
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bente, Klaas
T1 - The thermoacoustic effect and its application in air-coupled testing of composite structures
N2 - Airborne ultrasonic testing of lightweight, structured composite materials enables fast and contact-free non-destructive testing in aerospace and avoids material degradation due to contact with a coupling liquid. Established resonant air-coupled transducers consist of piezocomposite materials and several matching layers or more advanced materials like charged cellular polypropylene. The relaxation time and the specific frequency of such mechanical ultrasound emitters limit the spectrum of applications for each device. A short pulse length is key for reliable defect detection and each component at test can be best characterized at material- and geometry-specific frequencies. Here we show that focused thermoacoustic transducers are suited for testing lightweight, structured composite plates. Since the ultrasound is generated in air, these transducers show no resonance behavior and emit a broadband acoustic spectrum between 1.2 kHz and 1 MHz. Composite specimens of 3 mm to 9 mm thickness made of polylactide with a honeycomb structure were tested. Flat bottom holes were introduced to quantify the spatial resolution of the imaging method inside the strongly anisotropic specimen. As no broadband receivers are available yet, cellular polypropylene transducers were used as receivers, which limits the bandwidth of the method towards the bandwidth of the receiver. Nevertheless, we demonstrate the competitiveness of the thermoacoustic transducer compared to mechanical emitters at their respective resonance frequencies. Because a thermoacoustic transmitter features a nearly ideal pulse width, a single transmitter can be coupled with receivers with different resonance frequencies. With the development of broadband ultrasound receivers, air-coupled ultrasound spectroscopy will likely be possible in the near future. The analysed transducer holds the potential to speed up testing during production and maintenance in aerospace and automotives. Its combination with a broadband receiver could also expand the application field of air-coupled ultrasonic testing from a qualitative error detection towards a quantitative, spatially resolved analysis of mechanical material properties.
T2 - 10th International Symposium on NDT in Aerospace
CY - Dresden, Germany
DA - 24.10.2018
KW - Thermoacoustics
KW - Ultrasonic Testing
KW - Broadband
KW - Ultrasound Emission
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464677
SN - 978-3-940283-96-2
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-46467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Z.
A1 - Kruschwitz, Sabine
A1 - Weller, A.
A1 - Halisch, M.
T1 - Enhanced pore space analysis by use of µ-CT, MIP, NMR, and SIP
N2 - We investigate the pore space of rock samples with respect to different petrophysical parameters using various methods, which provide data on pore size distributions, including micro computed tomography (µ-CT), mercury Intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and spectral-induced polarization (SIP). The resulting cumulative distributions of pore volume as a function of pore size are compared. Considering that the methods differ with
regard to their limits of resolution, a multiple-length-scale characterization of the pore space is proposed, that is based on a combination of the results from all of these methods.
The approach is demonstrated using samples of Bentheimer and Röttbacher sandstone. Additionally, we compare the potential of SIP to provide a pore size distribution with other commonly used methods (MIP, NMR). The limits of Resolution of SIP depend on the usable frequency range (between 0.002 and 100 Hz). The methods with similar Resolution show a similar behavior of the cumulative pore volume distribution in the verlapping pore size range. We assume that µ-CT and NMR provide the pore body size while MIP and SIP characterize the pore throat size. Our study Shows that a good agreement between the pore radius distributions can only be achieved if the curves are adjusted considering the resolution and pore volume in the relevant range of pore radii. The MIP curve with the widest range in Resolution should be used as reference.
KW - Pore space
KW - Induced polarization
KW - Mercury intrusion porosimetry
KW - µ-CT
KW - NMR
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465071
DO - https://doi.org/10.5194/se-9-1225-2018
SN - 1869-9510
SN - 1869-9529
VL - 9
IS - 6
SP - 1225
EP - 1238
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-46507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlichting, S.
A1 - Hönig, Gerald
A1 - Müßener, J.
A1 - Hille, P.
A1 - Grieb, T.
A1 - Westerkamp, S.
A1 - Teubert, J.
A1 - Schörmann, J.
A1 - Wagner, M.R.
A1 - Rosenauer, A.
A1 - Eickhoff, M.
A1 - Hoffmann, A.
A1 - Callsen, G.
T1 - Suppression of the quantum-confined Stark effect in polar nitride heterostructures
N2 - Recently, we suggested an unconventional approach (the so-called Internal-Field-Guarded-Active-Region Design “IFGARD”) for the elimination of the quantum-confined Stark effect in polar semiconductor heterostructures. The IFGARD-based suppression of the Stark redshift on the order of electronvolt and spatial charge carrier separation is independent of the specific polar semiconductor material or the related growth procedures. In this work, we demonstrate by means of micro-photoluminescence techniques the successful tuning as well as the elimination of the quantum-confined Stark effect in strongly polar [000-1] wurtzite GaN/AlN nanodiscs as evidenced by a reduction of the exciton lifetimes by up to four orders of magnitude. Furthermore, the tapered geometry of the utilized nanowires (which embed the investigated IFGARD nanodiscs) facilitates the experimental differentiation between quantum confinement and Stark emission energy shifts. Due to the IFGARD, both effects become independently adaptable.
KW - Nanophotonics
KW - Photonic devices
KW - Single photon and quantum effects
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457884
DO - https://doi.org/10.1038/s42005-018-0044-1
SN - 2399-3650
VL - 1
SP - 1
EP - 8
PB - Springer Nature
CY - London
AN - OPUS4-45788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Camp, N. V.
A1 - Kalinka, Gerhard
A1 - Bergeler, J.
T1 - Light-cured polymer electrodes for non-invasive EEG recordings
N2 - We invented the first non-metallic, self-adhesive and dry biosignalling electrode. The PEDOT polymer electrode changes its aggregate state and conductivity by a light curing procedure. The electrode can be applied as a gel underneath hair without shaving. With the aid of blue light, the electrode can be hardened within a few seconds at the desired location on the scalp. The cured polymer electrode is highly conductive and can be applied on a very small location. Unlike other EEG electrodes, our electrode does not lose conductivity upon drying. Furthermore, our electrode strongly bonds to Skin and does not require any additional adhesive. Short circuits due to an outflow of gel are prevented with this technique. Therefore, the PEDOT polymer electrode is extremely well suited for applications that, up to now, have been challenging, such as non-invasive EEG recordings from awake and freely moving animals, EEG recordings from preterm babies in the neonatal intensive care unit or long-term recordings in the case of sleep monitoring or epilepsy diagnostics. We addressed two technical questions in this work. First, is the EEG recorded with polymer electrodes comparable to a standard EEG? Second, is it possible to record full-band EEGs with our electrodes?
KW - Light curing
KW - Polymer
KW - Electric conductivity
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459803
UR - https://rdcu.be/7aPD
DO - https://doi.org/10.1038/s41598-018-32304-6
SN - 2045-2322
VL - 8
IS - 14041
SP - 1
EP - 9
PB - Nature Publishing Group
CY - London
AN - OPUS4-45980
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhandarov, S.
A1 - Mäder, E.
A1 - Kalinka, Gerhard
A1 - Scheffler, C.
A1 - Poitzsch, C.
A1 - Fliescher, S.
T1 - Investigation of interfacial strength parameters in polymer matrix composites: Compatibility and reproducibility
N2 - Effects of various geometrical and physical factors, as well as the method of data reduction (analysis of
experimental forceedisplacement curves) on the values of local interfacial strength parameters (local IFSS, td, and critical energy release rate, Gic) determined by means of a single fiber pull-out test are discussed. Experimental results of our pull-out tests on several fiberepolymer matrix systems showed that td and Gic weakly depended on geometrical factors. However, the pull-out test appeared to be sensitive to the conditions of specimen formation and testing, such as changing the nature of the contacting surfaces (fiber sizing) and the fiber pull-out rate. Of several methods of td and Gic Determination from a forceedisplacement curve, the most reliable and reproducible one is the approach based on the values of the maximum force recorded in a pull-out test and the interfacial frictional force immediately after fiber debonding.
KW - Interface
KW - Interfacial shear strength
KW - Pull-out composite materials
KW - Polymer matrix composites
KW - Critical energy release rate
KW - Geometrical factors
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-460918
DO - https://doi.org/10.1016/j.aiepr.2018.06.002
SN - 2542-5048
VL - 1
IS - 1
SP - 82
EP - 92
PB - Elsevier
CY - Amsterdam
AN - OPUS4-46091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Schadow, Florian
A1 - Nielow, Dustin
A1 - Trappe, Volker
T1 - Air-coupled ultrasonic ferroelectret transducers with additional bias voltage for testing of composite structures
N2 - Common air-coupled transducers for non-destructive testing consist of a piezocomposite material and several matching layers. Better acoustical matching to air is achieved by transducers based on charged cellular polypropylene (PP). This material has about hundred times lower acoustic impedance than any piezocomposite, having about the same piezoelectric coefficient. The piezoelectric properties of cellular PP are caused by the polarization of air cells. Alternatively, a ferroelectret receiver can be understood as a capacitive microphone with internal polarization creating permanent internal voltage. The sensitivity of the receiver can be increased by applying additional bias voltage. We present an ultrasonic receiver based on cellular PP including a high-voltage module providing bias voltage up to 2 kV. The application of bias voltage increased the signal by 12 to 15 dB with only 1 dB increase of the noise.
This receiver was combined with a cellular PP transmitter in through transmission to inspect several test specimens consisting of glass-fiber-reinforced polymer face sheets and a porous closed-cell PVC core. These test specimens were inspected before and after load. Fatigue cracks in the porous PVC core and some fatigue damage in the face sheets were detected. These test specimens were originally developed to emulate a rotor blade segment of a wind power plant. Similar composite materials are used in lightweight aircrafts for the general aviation. The other inspected test specimen was a composite consisted of glass-fiber-reinforced polymer face sheets and a wooden core. The structure of the wooden core could be detected only with cellular PP transducers, while commercial air-coupled transducers lacked the necessary sensitivity. Measured on a 4-mm thick carbon-fiber-reinforced polymer plate, cellular PP transducers with additional bias voltage achieved a 32 dB higher signal-to-noise ratio than commercial air-coupled transducers.
T2 - 10th International Symposium on NDT in Aerospace
CY - Dresden, Germany
DA - 26.10.2018
KW - Airborne ultrasonic testing
KW - Air-coupled ultrasonic testing
KW - Ferroelectret
KW - Composites
KW - Transducers
PY - 2018
SP - 1
EP - 6
AN - OPUS4-46657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maiwald, Michael
T1 - Voll integrierte und vernetzte Systeme und Prozesse - Perspektive: Smarte Sensorik, Aktorik und Kommunikation
T1 - Fully integrated distributed systems and processes – Perspective: Smart sensors, actuators, and communication
N2 - Unternehmen der chemischen Industrie müssen neuen Pfade beschreiten, um in einem veränderten Umfeld erfolgreich bestehen zu können. Dazu gehört insbesondere, das Potenzial digitaler Technologien zu nutzen. Die volle Integration und intelligente Vernetzung von Systemen und Prozessen kommt allerdings nur zögerlich voran. Dieser Beitrag ist ein Loblied auf die Feldebene. Er möchte dazu ermutigen, die Digitalisierung der Prozessindustrie auf Basis smarter Sensorik, Aktorik und Kommunikation ganzheitlicher zu denken und informiert über aktuelle technische Perspektiven, wie das Ein-Netzwerk-Paradigma, Ad-hoc-Vernetzungen, Edge-Computing, FPGAs, virtuelle Maschinen oder Blockchain. Diese geben smarter Sensorik, Aktorik und Kommunikation eine völlig neue Perspektive.
N2 - Chemical companies must find new paths to success in a changing environment. In particular, this will involve exploiting the potential of digital technologies. However, the full integration and intelligent interconnection of systems and processes is only making slow progress. This contribution aims to encourage the more comprehensive use of digitization in the process industry based on smart sensors, actuators, and communications, and informs about current technical possibilities such as the “one-network paradigm”, ad-hoc connections, edge computing, FPGAs, virtual machines and blockchain. These offer a new scope for smart sensors, actuators, and communications.
KW - Smarte Sensoren
KW - Smarte Aktoren
KW - Digitalisierung der Prozessindustrie
KW - Prouess-Sensoren 4.0
KW - Smart sensors
KW - Smart actuators
KW - Digitization of process industry
KW - Process sensors 4.0
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-466642
DO - https://doi.org/10.17560/atp.v60i10.2376
SN - 2364-3137
VL - 60
IS - 10
SP - 70
EP - 85
PB - Vulkan Verlag
CY - Essen
AN - OPUS4-46664
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ivanov, Sergei
A1 - Artinov, Antoni
A1 - Valdaytseva, Ekaterina
A1 - Stankevich, Stanislav
A1 - Andreevich, Gleb
T1 - A simplified model for numerical simulation of laser metal deposition process with beam oscillation
N2 - A model of laser metal deposition with beam oscillation has been developed. The proposed model consists of two coupled sub-models calculating the heat transfer in the deposited part and the free surface of the molten pool, respectively. The heat transfer simulation of the deposited part solves a three-dimensional quasi-stationary heat conduction problem. The free surface of the molten pool are determined by solving the Laplace-Young equation. The developed model enables the layer-by-layer prediction of the shape of the deposited part and the resulting temperature field. It is shown that for an oscillation amplitude equal to the beam radius the peak value of the heat flux decreases by about 53% and 73% in the case of lateral oscillation and circular oscillation, respectively. Lateral oscillating laser beam results in a higher penetration depth due to the higher thermal efficiency. The amplitude of the laser beam oscillation effects the shape of the deposited wall and the deposition rate. A good correlation between the numerically calculated and experimentally observed results is obtained.
KW - Laser metal deposition
KW - Beam oscillation
KW - Numerical modelling
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467081
DO - https://doi.org/10.1088/1742-6596/1109/1/012006
SN - 1742-6588
SN - 1742-6596
VL - 1109
SP - 012006, 1
EP - 8
PB - IOP Publ.
CY - Bristol
AN - OPUS4-46708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hu, Wei-Hua
A1 - Tang, De-Hui
A1 - Teng, Jun
A1 - Said, Samir
A1 - Rohrmann, Rolf
T1 - Structural health monitoring of a prestressed concrete bridge based on statistical pattern recognition of continuous dynamic measurements over 14 years
N2 - This work describes a vibration-based structural health monitoring of a prestressed-concrete box girder bridge on the A100 Highway in Berlin by applying statistical pattern recognition technique to a huge amount of data continuously collected by an integrated monitoring system during the period from 2000 to 2013. Firstly, the general condition and potential damage of the bridge is described. Then, the dynamic properties are extracted from 20 velocity sensors. Environmental variability captured by five thermal transducers and traffic intensity approximately estimated by strain measurements are also reported. Nonlinear influences of temperature on natural frequencies are observed. Subsequently, the measurements during the first year are used to build a baseline health index. The multiple linear regression (MLR) method is used to characterize the nonlinear relationship between natural frequencies and temperatures. The Euclidean distance of the residual errors is calculated to build a statistical health index. Finally, the indices extracted from the following years gradually deviate; which may indicate structural deterioration due to loss of prestress in the prestressed tendons.
KW - Bridge
KW - Structural health monitoring
KW - Statistical pattern recognition
KW - Temperature effect
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468126
DO - https://doi.org/10.3390/s18124117
SN - 1424-8220
VL - 18
IS - 12
SP - 4117, 1
EP - 28
PB - MDPI
CY - 4052 Basel, Schweiz
AN - OPUS4-46812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kauss, N.
A1 - Rosemann, Paul
A1 - Halle, T.
T1 - Age-hardening behaviour, microstructure and corrosion resistance of the copper alloyed stainless steel 1.4542
N2 - The copper alloyed stainless steel 1.4542 (X5CrNiCuNb16-4) is used in different areas due to its good mechanical properties and corrosion resistance. Strength and corrosion resistance can be adjusted by the heat treatment, which is of importance for the application of this alloy. The mechanical properties (strength and hardness) are attributed to the dispersive precipitation of the copper rich ε–Phase. The additional precipitation of chromium carbides can reduce the corrosion resistance. Different ageing states were produced to investigate the precipitation behaviour with various methods. Furthermore, the influence of cold-rolling on the precipitation behaviour was studied in comparison to a solution annealed state without deformation. The microstructure was studied by SEM and the variations of hardness and magnetic proportion were characterised. The electrochemical potentiodynamic reactivation
(EPR) was used to determine the corrosion resistance and detect chromium depletion in all heattreated states. The results show that a work hardening accelerates the precipitation rate, while ageing at 600 °C reduces the corrosion resistance due to chromium depletion.
T2 - WTK2018
CY - Chemnitz
DA - 14.03.2018
KW - Corrosion
KW - Corrosion resistance
KW - Corrosion testing
KW - EPR
KW - Heat treatment
KW - Stainless steel
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452482
DO - https://doi.org/10.1088/1757-899X/373/1/012020
SN - 1757-899X
SN - 1757-8981
VL - 373
SP - Article 012020, 1
EP - 9
PB - Institute of Physics
CY - London
AN - OPUS4-45248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lugovtsova, Yevgeniya
A1 - Prager, Jens
T1 - Analysis of Guided Wave Propagation in an Aluminium-CFRP Plate
N2 - Guided waves cover comparably long distances and thus allow for online structural health monitoring of safety relevant components, e.g. lightweight composite overwrapped pressure vessels (COPV) as used for the transportation of pressurised gases. Reliable non-destructive assessment of COPVs’ condition is not available yet due to their complex composite structure comprising a thin metal liner and a fibre reinforced plastics (FRP) overwrap. The conventional overload hydrostatic pressure testing used for the metal vessels is not suitable for the composite vessels, because it may damage the FRP overwrap reducing the service life of the COPV. Therefore, ISO and CEN defined a maximum service life of composite pressure vessels as of 15 to 20 years. To extend the COPVs’ service life and to ensure a safer usage a structural health monitoring system based on guided ultrasonic waves is to be developed.
In this contribution first results of guided waves propagation in a flat composite plate consisting of an aluminium layer firmly bonded to a carbon fibre reinforced plastic laminate are presented. Based on experimental results material properties of FRP are reconstructed by means of the Scaled Boundary Finite Element Method (SBFEM).
T2 - ECNDT 2018
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - Structural Health Monitoring
KW - Pressure tanks
KW - Hydrogen storage
KW - Natural gas
KW - Composites
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452084
SP - 1
EP - 6
AN - OPUS4-45208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Kotschate, Daniel
T1 - New technologies for air-coupled ultrasonic transducers
N2 - Air-coupled ultrasonic testing (ACUT) has experienced rapid growth within the last years. It is especially well suited to inspection of lightweight structures consisting of composite materials and adhesive joints. Uniform coupling and easy maintenance are its advantages compared to contact technique. However, the impedance mismatch between the transducer and air poses a major challenge to the development of ACUT transducers. Commercially available air-coupled transducers consist of a piezocomposite material and matching layers. Their fabrication is difficult in handling and their signal-to-noise ratio sometimes not sufficient for various testing requirements. However, there are several innovative approaches using other materials and other physical principles to transmit and receive an ultrasonic pulse. We present a review of the latest advances in research on air-coupled transducers for non-destructive testing, including previously unpublished results. We recognize two major directions as most promising: ferroelectrets and thermoacoustic transducers. Ferroelectrets are charged cellular polymers exhibiting piezoelectric properties. Their small acoustic impedance is matched to air better than matching layers applied in conventional air-coupled transducers. Applying bias voltage to a ferroelectret receiver is the latest development in this field, which increased the received signal by 12 to 15 dB. Thermoacoustic transducers use heat to initiate an ultrasonic wave, acting as transmitters. The working principle is known from nature as thunder and lightning: thermal energy of an electrically heated material, which can also be air, is converted into acoustic energy. Some thermoacoustic transmitters consist of a conductive layer with a thickness in the nanometer range deposited on a solid substrate. Another possibility is to use an electric spark. For the first time, measurements of the sound field of an electric spark up to 500 kHz were performed. Thermoacoustic transducers enable excitation of extremely broadband pulses while producing high pressure levels, which opens new possibilities for advanced signal processing.
T2 - 12th European conference on Non-Destructive Testing
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - Air-coupled ultrasonic testing
KW - Atmospheric pressure plasma
KW - Cellular polypropylene
KW - Ferroelectret
KW - Transducer
PY - 2018
SP - ECNDT-0608-2018, 1
EP - 9
AN - OPUS4-45209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grager, J.-C.
A1 - Kotschate, Daniel
A1 - Gamper, J.
A1 - Gaal, Mate
A1 - Pinkert, K.
A1 - Mooshofer, H.
A1 - Goldammer, M.
A1 - Grosse, C. U.
T1 - Advances in air-coupled ultrasonic testing combining an optical microphone with novel transmitter concepts
N2 - Air-coupled ultrasound (ACU) is increasingly used for automated and contactless inspection of large-scale composite structures as well as for non-destructive testing (NDT) of water-sensitive or porous materials. The major challenge to overcome using ACU in NDT is the enormous loss of ultrasonic energy at each solid-air interface caused by the high acoustic impedance mismatch. Resonant low-frequency piezoceramic transducers are specially designed to achieve high sound pressure levels. For an expanded use of this technique, however, the spatial resolution needs to be increased.
Recent studies of our collaborative research group demonstrated the successful application of a resonance-free, highly sensitive receiver that uses a Fabry-Pérot etalon instead of piezoceramic materials or membranes. However, to reach the full potential of this broadband small-aperture optical microphone, novel transmitter concepts have to be developed and evaluated for advanced NDT applications.
Different types of transmitter were tested in combination with the optical microphone acting as receiver and they were compared to conventional piezoceramic transducers in through-transmission mode. Monolithic carbon fiber-reinforced plastics (CFRP) and CFRP sandwich structures containing different defect types were inspected. Presented results are processed as C-scan images and further evaluated for spatial resolution, signal-to-noise ratio and sensitivity of each measurement setup. Novel transmitter concepts, such as ferroelectret and thermoacoustic emitters, show promising findings with a considerably improved time and spatial resolution for ACU-NDT.
T2 - 12th European conference on Non-Destructive Testing
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - Air-coupled ultrasonic testing
KW - Optical microphone
KW - Thermoacoustic
KW - Cellular polypropylene
KW - Ferroelectret
KW - Transducer
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452114
SP - ECNDT-0166-2018, 1
EP - 10
AN - OPUS4-45211
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Franz, Philipp
A1 - Metz, Christain
A1 - Brackrock, Daniel
A1 - Fischer, C.
A1 - Wachtendorf, Volker
A1 - Maierhofer, Christiane
T1 - Zerstörungsfreie Charakterisierung und Qualitätssicherung der Materialeigenschaften und Beständigkeit additiv gefertigter Kunststoffteile
N2 - Mit additiven Fertigungsverfahren hergestellte Bauteile und Produkte aus Kunststoffen werden zunehmend nicht mehr nur als Prototypen, sondern als voll funktionsfähige Bauteile und Produkte gefertigt. Bedingt durch die Fertigungsprozesse und den schichtweisen Aufbau resultieren physikalische Materialeigenschaften, die stark von den Fertigungsparametern abhängen und zudem anisotrop sind. Von den Fertigungsparametern werden auch die Oberflächeneigenschaften beeinflusst, sodass zu erwarten ist, dass sich die Beständigkeit gegenüber äußeren Umwelteinflüssen bei additiv gefertigten Bauteilen von der konventionell gefertigter unterscheiden kann. Nachfolgend wird daher die Entwicklung eines Qualitätssicherungskonzeptes basierend auf spektroskopischen und zerstörungsfreien Prüfverfahren vorgestellt, in dem der Alterungsprozess von mittels Fused Deposition Modelling (FDM) und mittels Lasersintering (LS) hergestellten Probekörpern untersucht wird.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Additive Fertigung
KW - Kunststoffe
KW - Zerstörungsfreie Prüfung
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449016
SN - 978-3-940283-92-4
VL - DGZfP BB 166
SP - Mo.2.A.1, 1
EP - 9
AN - OPUS4-44901
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Legall, Herbert
A1 - Schwanke, Christoph
A1 - Pentzien, Simone
A1 - Dittmar, G.
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - X-ray emission as a potential hazard during ultrashort pulse laser material processing
N2 - In laser machining with ultrashort laser pulses unwanted X-ray radiation in the keV range can be generated when a critical laser intensity is exceeded. Even if the emitted X-ray dose per pulse is low, high laser repetition rates can lead to an accumulation of X-ray doses beyond exposure safety limits. For 925 fs pulse duration at a center wavelength of 1030 nm, the X-ray emission was investigated up to an intensity of 2.6 × 10^14 W/cm2. The experiments were performed in air with a thin disk laser at a repetition rate of 400 kHz. X-ray spectra and doses were measured for various planar target materials covering a wide range of the periodic table from aluminum to tungsten. Without radiation shielding, the measured radiation doses at this high repetition rate clearly exceed the regulatory limits. Estimations for an adequate radiation shielding are provided.
KW - Laser-induced X-ray emission
KW - Ultrashort laser material interaction
KW - Femtosecond laser
KW - Radiation protection
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448431
DO - https://doi.org/10.1007/s00339-018-1828-6
SN - 0947-8396
SN - 1432-0630
VL - 124
IS - 6
SP - Article 407, 1
EP - 8
PB - Springer
AN - OPUS4-44843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Maierhofer, Christiane
A1 - Röllig, Mathias
A1 - Heckel, Thomas
A1 - Brackrock, Daniel
A1 - Gaal, Mate
T1 - Charakterisierung von Impactschäden während und nach der Belastung mit thermografischen Verfahren und mit Ultraschall
N2 - Der Umfang der durch Impacts in Faserverbundmaterialien erzeugten Schäden ist abhängig von der Energie des Impacts, von der Zusammensetzung und dem Aufbau der Faserverbundwerkstoffe und von der Geometrie der Bauteile und hier im Wesentlichen von der Dicke des Bauteils. Der zerstörungsfreie Nachweis dieser Schädigungen kann sowohl mit Ultraschallverfahren als auch mit Verfahren der aktiven Thermografie erfolgen. Ein Vergleich der Nachweisempfindlichkeiten dieser Verfahren für die unterschiedlichen Schädigungen wird in diesem Beitrag in Abhängigkeit vom verwendeten Faserverbundwerkstoff (CFK und GFK), der Dicke des Materials und von der Impactenergie durchgeführt. Ergänzt werden die im Anschluss an die Schädigung eingesetzten ZfP-Verfahren mit zeitlich hochaufgelösten Thermografiemessungen, die bereits während des Impacts aufgenommen wurden.
T2 - DGZfP Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Thermografie
KW - Ultraschall
KW - Faserverbundwerkstoffe
KW - Impactschäden
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448773
SN - 978-3-940283-92-4
VL - 166
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-44877
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Illerhaus, Bernhard
A1 - Kunisch, E.
A1 - Kinne, R. W.
T1 - μCT begleitete in-situ Druckversuche an spongiösem Knochen - Vergleich(ende Bestimmung) des experimentellen und simulierten Verschiebungsfeldes mit der simulierten internen Spannung
N2 - Untersuchungen haben gezeigt, dass sich ältere Schafe gut als Modell für die mi-nimalinvasive Behandlung von Osteoporose eignen [1]. Um einen Behandlungs-effekt nachzuweisen, wird dabei unter anderem die Belastungsfähigkeit des Kno-chens durch Druckversuche an kleinen Zylindern aus den behandelten und unbe-handelten Knochen bestimmt. Diese hatten hier einen Durchmesser von 10 mm und eine Höhe von 13 mm. Für den in-situ Druckversuch wurde eine Deben CT5000 verwendet. In einer Serie von Druckerhöhungen wurden die Proben je-weils tomographiert. Dabei ergab sich zunächst, dass mit der µCT innerhalb der Knochen im oberen und unteren Bereich schon Brüche nachgewiesen werden können, obwohl die gemessene Kraftaufnahmekurve keine Unstetigkeit zeigt. Deswegen wurden die starren Probenaufnehmer der Deben Anordnung durch bewegliche Aufnehmer ergänzt, die eine leichte Verkippung der belasteten Ober-flächen ausgleichen können. Ein Vergleich der gemessenen und der aus den µCT-Daten berechneten Verschiebungsfelder ergab trotz der komplexen Struktur der Knochen gute Übereinstimmungen. Diese Verschiebungen wurden dann mit den aus den µCT Daten simulierten mechanischen Druckversuchen, Von-Mise-Spannungen und daraus berechneten Verschiebungen verglichen. (VGStudioMax Simulation).
T2 - DGZfP-Jahrestagung
CY - Leipzig, Germany
DA - 07.05.2018
KW - Computer Tomographie
KW - In-situ Druckversuch
KW - Simulation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448827
UR - https://www.ndt.net/?id=23080
SN - 978-3-940283-92-4
VL - DGZfP BB 166
SP - 1
EP - 7
PB - DGZfP
CY - Berlin
AN - OPUS4-44882
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kapa, Thomas
A1 - Schreier, Andy
A1 - Krebber, Katerina
T1 - 63 km BOFDA for temperature and strain monitoring
N2 - We demonstrate (and are the first to do so) 63 km Brillouin Optical Frequency-Domain Analysis (BOFDA) for temperature and strain monitoring using a 100 km fiber loop. The use of BOFDA for long-range applications can be considered a novel approach, as previous investigations focused on the utilization of Brillouin Optical Time-Domain Reflectometry and Analysis (BOTDR and BOTDA, respectively). At 51.7 km, a 100 m hotspot (37 °C) was detected without using distributed Raman amplification or image processing.
KW - Distributed sensing
KW - Stimulated Brillouin scattering
KW - Fiber optics sensors
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449679
DO - https://doi.org/10.3390/s18051600
SN - 1424-8220
VL - 18
IS - 5
SP - 1600, 1
EP - 9
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-44967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Holm, Olaf
T1 - Resources from recycling and urban mining: Limits and prospects
N2 - Direct and indirect effects (DIERec) of the recovery of secondary resources are in the range of 500 million tons per year in Germany; energy savings are 1.4 million TJ. These savings are between 10 and 20% of the total. The effects of materials recovery exceed those of energy recovery by far except for secondary plastic material, where DIERec from energy recovery is higher by factor of 2.7. Untapped potential for the recovery of secondary resources exists in the fine fraction of bottom ash from municipal solid waste incineration, mainly Cu and precious metals, and in urban mining.
KW - Waste treatment
KW - Secondary raw materials
KW - Direct material input
KW - Urban mining
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453364
UR - https://digital.detritusjournal.com/articles/resources-from-recycling-and-urban-mining-limits-and-prospects/124
DO - https://doi.org/10.31025/2611-4135/2018.13665
SN - 2611-4135
VL - 02
SP - 24
EP - 28
PB - CISA Publisher
CY - Padua, Italy
AN - OPUS4-45336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Metz, Christian
A1 - Franz, Philipp
A1 - Fischer, C.
A1 - Wachtendorf, Volker
A1 - Maierhofer, Christiane
T1 - Active thermography for quality assurance of 3D-printed polymer structures
N2 - Additively manufactured test specimens made of polyamide 12 (PA 12) by Laser Sintering (LS) as well as of acrylnitril-butadien-styrol (ABS) by Fused Layer Modeling (FLM), were tested with active thermography. For this, two different excitation methods (flash and impulse excitation) were used and compared, regarding the suitability for the detection of constructed and imprinted defects. To increase the quality of the thermograms, data processing methods like thermal signal reconstruction (TSR) and Fourier-Transformation were applied. Furthermore, the long-term stability of the probes towards environmental stress, like UV-radiation, heat, water contact and frost is being investigated in the presented project with artificial weathering tests.
T2 - 14th Quantitative InfraRed Thermography Conference
CY - Berlin, Germany
DA - 25.06.2018
KW - Additive manufacturing
KW - Active thermography
KW - Artificial weathering
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453919
SP - Tu.3.A.2, 1
EP - 9
AN - OPUS4-45391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Illerhaus, Bernhard
A1 - Kunisch, E.
A1 - Kinne, R. W.
T1 - Serial in situ compression of spongiosa cylinder observed by μCT, compared to simulated stress, strain, and movement
N2 - Minimally invasive injection of calcium phosphate cement into bone defects in aged sheep vertebrae has been used as a model for the treatment of osteoporotic vertebral fractures. One of the therapeutic criteria is a compression test of non-treated or treated vertebral bodies. In the present study, an in situ compression test with a stepwise load increase was performed with small spongiosa cylinders from the vertebrae under continuous monitoring by μCT. This allows localization of bone cracks and the visualization of correct placement and form of the bone cylinder. In addition, the effects of an uneven load distribution on the sample due to an irregular shape and a subsequent underperformance of the test sample can be excluded by controlling its shape under increasing load. There was a good agreement between the measured data and those obtained by simulated load-dependent transformation on the basis of a digital volume correlation between consecutive compression tests on the bone surface under the assumption of homogeneous bone material. Mechanic simulation was executed by directly using structural voxel data, resulting in maps of Von Mise stresses and predicted displacements.
T2 - 12th ECNDT
CY - Gothenburg, Sweden
DA - 11.6.2018
KW - Computed tomography
KW - In-situ compression
KW - Simulation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453317
SN - 978-91-639-6217-2
SP - 0162, 1
EP - 7
AN - OPUS4-45331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Schadow, Florian
A1 - Nielow, Dustin
A1 - Trappe, Volker
T1 - Prüfung von Rotorblattschalen mit Luftultraschall
N2 - Um den sicheren Betrieb von Windkraftanlagen zu gewährleisten, werden Rotorblätter nach der Fertigung und nach Reparatur mit verschiedenen zerstörungsfreien Verfahren auf Schaden untersucht. Bei der Fertigung von Blattschalen, die in einer Sandwich-Schalenbauweise gefertigt werden, entstehen Imperfektionen, die unter Belastung zu großen Rissen führen können. Zur Prüfung von Blattschalen wird unter anderem Ultraschallprüfung in Kontakttechnik eingesetzt. Um den Wartungsaufwand von Ultraschallanlagen zu reduzieren und um manche Kompositstrukturen vor Koppelmittel zu schützen, wird die Anwendung von Luftultraschall erforscht. Insbesondere große Fortschritte gibt es im Bereich der Entwicklung neuer Wandler.
In diesem Beitrag berichten wir über die Luftultraschallprüfung von Schalen für Rotorblätter. Es wurden typische Sandwichschalenstrukturen hergestellt und mit einem eigenentwickelten Schalenprüfstand unter simulierter Betriebsbeanspruchung belastet. Die in den Schalenprüfkörpern entstandenen Schäden wurden außerhalb des Prüfstandes mit Luftultraschall in Durchschallung untersucht. Es wurden fokussierende Wandler auf Basis von Ferroelektreten entwickelt und für diese Prüfungen eingesetzt. Mit zusätzlicher elektrischer Vorspannung konnte die Empfindlichkeit der Empfänger deutlich erhöht werden. Die nach dem Lastwechsel entstandenen Schäden in den Rotorblattschalen waren eindeutig zu detektieren.
T2 - DGZfP-Jahrestagung
CY - Leipzig, Germany
DA - 07.05.2018
KW - Wandler
KW - Rotorblattschalen
KW - Luftultraschall
KW - Ferroelektret
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453066
SP - 7
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-45306
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Maierhofer, Christiane
A1 - Heckel, Thomas
A1 - Brackrock, Daniel
A1 - Gower, M.
A1 - Lodeiro, M.
A1 - Baker, G.
T1 - Quantitative comparison of different non-destructive techniques for the detection of artificial defects in GFRP
N2 - In order to test their suitability different non-destructive methods were performed to inspect a GFRP plate with artificial defects. These defects were manufactured by means of thin PTFE sheets inserted between two plies in three different depth. The inspection methods were microwave reflection, flash thermography and phased array ultrasonics, all applied to the same specimen. Selected results are shown for all methods demonstrating opportunities and limits of the particular inspection methods. The achieved detection limits and further application aspects are compared directly to provide a useful information for the planning of inspection tasks.
T2 - ECNDT
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - Fiber resisted polymers
KW - Non-destructive testing
KW - Thermographic testing
KW - Ultrasonic testing
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453728
SP - ECNDT-0247-2018
AN - OPUS4-45372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Ziegler, Mathias
A1 - Maierhofer, Christiane
ED - Maldague, X.
T1 - Systematic errors in the evaluation of uncorrected data from thermographic lock-in measurements
N2 - Lock-in thermography (LT) is based on the correct evaluation of phase differences between the temperature oscillations at different surface regions of the object under test during periodic heating. Since the usual heating procedures contain a DC component, the actual heating pattern achieved is not harmonic. This causes systematic deviations when phase differences are determined by means of harmonic analysis, e.g. with FFT analysis. The resulting errors depend clearly on the ratio between DC and AC amplitude, which is demonstrated at simulated and experimentally recorded temperature transients. Further experimental LT data obtained by different oscillating energy inputs showed a variety of possible shapes of transients with different DC components.
T2 - 14th QIRT Conference
CY - Berlin, Germany
DA - 26.06.2018
KW - NDT
KW - Lock-in Thermography
KW - FFT
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453768
SP - 539
EP - 547
PB - QIRT Council
AN - OPUS4-45376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Swaraj, S.
A1 - Sparnacci, K.
A1 - Unger, Wolfgang
T1 - Shell thickness determination for PTFE‐PS core‐shell nanoparticles using scanning transmission X‐ray microscopy (STXM)
N2 - A scanning transmission X‐ray microscopy (STXM)‐based methodology is introduced for determining the dimensions (shell thickness, core and total diameter) of core‐shell nanoparticles, which exhibit a strong X‐ray absorption contrast and a well‐defined interface between core and shell material. A low radiation dosage during data acquisition and, therefore, less X‐ray beam‐induced damage of the sample is achieved by recording STXM images only at 2 predetermined energies of maximum Absorption contrast, instead of recording a stack of images across the whole absorption edge.
A model core‐shell nanoparticle, polytetrafluoroethylene (PTFE) cores with polystyrene (PS) shell, is used for demonstration. Near‐edge X‐ray absorption fine structure spectroscopy confirms the significant difference in X‐ray absorption behavior between PTFE and PS. Additionally, because of the insolubility of styrene in PTFE a well‐defined interface between particle core and shell is expected. To validate the STXM results, both the naked PTFE cores as well as the complete core‐shell nanoparticles are examined by scanning electron microscopy (SEM). The introduced STXM‐based methodology yields particle dimensions in agreement with the SEM results and provides additional information such as the position of the particle core, which cannot be extracted from a SEM micrograph.
T2 - European conference on applications of surface and interface analysis (ECASIA'17)
CY - Montpellier, France
DA - 24.09.2017
KW - Core-shell nanoparticles
KW - Polymers
KW - PS
KW - PTFE
KW - SEM
KW - STXM
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449700
DO - https://doi.org/10.1002/sia.6464
SN - 1096-9918
SN - 0142-2421
VL - 50
IS - 11
SP - 1077
EP - 1082
PB - John Wiley & Sons
CY - Hoboken, New Jersey, USA
AN - OPUS4-44970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Krome, Fabian
A1 - Prager, Jens
T1 - Effiziente Modellierung von geführten Wellen mit der Scaled Boundary Finite Elemente Methode und deren Anwendung für Composite-Druckbehälter
N2 - Die Scaled Boundary Finite Elemente Methode (SBFEM) ist eine semi-analytische Methode, die speziell für Modellierung von geführten Wellen weiterentwickelt und optimiert wurde. Da nur den Rand der Rechendomäne diskretisiert wird, hat die SBFEM einen geringen Rechenaufwand. In diesem Beitrag wird die SBFEM benutzt, um die Ausbreitung geführter Wellen in einer Metall-Faserverbund-Werkstoffstruktur zu analysieren. Mittels der SBFEM ist es möglich, verschiede Fehlertypen, z.B. Ermüdungsrisse, Poren, Delaminationen, Korrosion, in das numerische Modell zu integrieren und damit Defekt-Mode-Wechselwirkung zu analysieren. Die Ergebnisse wurden für die Entwicklung einer Methode zur Zustandsüberwachung von Composite-Druckbehältern verwendet.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Wasserstoffspeicher
KW - Automobilindustrie
KW - Kohlenstofffaserverstärkter Kunststoff
KW - Hybrid Materialien
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449797
SP - 1
EP - 4
AN - OPUS4-44979
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilrich, Cordula
A1 - Brandes, E.
A1 - Michael-Schulz, Heike
A1 - Schröder, Volkmar
A1 - Schwarz, Silke
T1 - Classification of chemicals according to UN-GHS and EU-CLP: A review of physical hazard classes and their intricate interfaces to transport and former EU legislation
N2 - The Globally Harmonized System of Classification and Labelling of Chemicals (UN-GHS) is being implemented in more and more countries all over the world; the EU has done so with the CLP-Regulation (EU-CLP). Compared to the undeniably important questions on health and environmental hazards, the classification of physical hazards of chemicals often has not been in the focus, although their implementation can be challenging and there are traps and pitfalls to be avoided. The following overview of the classification systematics for physical hazards aims at a principle understanding without detailing all criteria or test methods. Similarities and differences between the classification systems of the UN-GHS and EU-CLP, the transport of dangerous goods and the former EU system are reviewed with regard to the physical hazard classes. Available physical hazard classifications for the transport of dangerous goods and according to the former EU system can be used as available information when classifying according to the GHS. However, the interfaces of these classification systems and their limitations have to be understood well when concluding on GHS/CLP classifications. This applies not only to industry when applying CLP but especially to legislators when adapting legislation that in one way or another refers to the classification of chemicals.
KW - Chemicals classification
KW - Globally harmonized system of classification and labelling of chemicals
KW - Hazardous chemicals
KW - Physical hazards
KW - UN-GHS
KW - EU-CLP
KW - CLP-regulation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-450012
UR - https://osjournal.org/ojs/index.php/OSJ/article/view/1389
DO - https://doi.org/10.23954/osj.v3i2.1389
SN - 2466-4308
VL - 3
IS - 2
SP - 1
EP - 24
PB - NVO Start
CY - Temerin
AN - OPUS4-45001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dmitriev, A. I.
A1 - Nikonov, A. Y.
A1 - Österle, Werner
T1 - Molecular dynamics modeling of the sliding performance of an amorphous silica nano-layer - The impact of chosen interatomic potentials
N2 - The sliding behavior of an amorphous silica sample between two rigid surfaces is in the focus of the present paper. Molecular Dynamics using a classical Tersoff’s potential and a recently developed ReaxFF potential was applied for simulating sliding within a thin film corresponding to a tribofilm formed from silica nanoparticles. The simulations were performed at different temperatures corresponding to moderate and severe tribological stressing conditions. Simulations with both potentials revealed the need of considering different temperatures in order to obtain a sound interpretation of experimental findings. The results show the striking differences between the two potentials not only in terms of magnitude of the resistance stress (about one order of magnitude) but also in terms of friction mechanisms. The expected smooth sliding regime under high temperature conditions was predicted by both simulations, although with Tersoff’s potential smooth sliding was obtained only at the highest temperature. On the other hand, at room temperature Tersoff-style calculations demonstrate stick-slip behavior, which corresponds qualitatively with our experimental findings. Nevertheless, comparison with a macroscopic coefficient of friction is not possible because simulated resistance stresses do not depend on the applied normal pressure.
KW - Molecular dynamics
KW - Thin tribofilm
KW - Resistance stress
KW - Sliding simulation
KW - Amorphous silica
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449366
DO - https://doi.org/10.3390/lubricants6020043
SN - 2075-4442
VL - 6
IS - 2
SP - 43, 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-44936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaiser, T. M.
A1 - Braune, C.
A1 - Kalinka, Gerhard
A1 - Schulz-Kornas, E.
T1 - Nano-indentation of native phytoliths and dental tissues: implications for herbivore-plant combat and dental wear proxies
N2 - Tooth wear induced by abrasive particles is a key process affecting dental function and life expectancy in mammals. Abrasive particles may be plant endogenous opal phytoliths, exogene wind-blown quartz dust or rain borne mineral particles ingested by mammals. Nano-indentation hardness of abrasive particles and dental tissues is a significant yet not fully established parameter of this tribological system. We provide consistent nano-indentation hardness data for some of the major antagonists in the dental tribosystem (tooth enamel, tooth dentine and opaline phytoliths from silica controlled cultivation). All indentation data were gathered from native tissues under stable and controlled conditions and thus maximize comparability to natural systems. Here we show that native (hydrated) wild boar enamel exceeds any hardness measures known for dry herbivore tooth enamel by at least 3 GPa. The native tooth enamel is not necessarily softer then environmental quartz grit, although there is little overlap. The native hardness of the tooth enamel exceeds that of any silica phytolith hardness recently published. Further, we find that native reed phytoliths equal native suine dentine in hardness, but does not exceed native suine enamel. We also find that native suine enamel is significantly harder than dry enamel and dry phytoliths are harder than native phytoliths. Our data challenge the claim that the culprit of tooth wear may be the food we chew, but suggest instead that wear may relates more to exogenous than endogenous abrasives.
KW - Phytolith
KW - Indentation hardness
KW - Enamel
KW - Dentine
KW - Tooth wear
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-451417
UR - http://zoobank.org/5C7DBB2B-B27D-4CE6-9656-33C4A0DA0F39
DO - https://doi.org/10.3897/evolsyst.2.22678
VL - 2
SP - 55
EP - 63
PB - PENSOFT
CY - USA
AN - OPUS4-45141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qiao, Linan
A1 - Nagelschmidt, Sven
A1 - Herbrich, Uwe
T1 - Application of a Modified Arrhenius Equation to Describe the Time-Temperature Equivalence in Relaxation Analysis of Metal Seals
N2 - For the application of the time-temperature superposition principle a suitable relation is needed to describe the time-temperature shift factor α. Therefore, the Arrhenius equation is widely used due to its simple form and often leads to suitable results. Where, the Arrhenius equation presents a linear relation for the temperature-dependent shift factor in logarithmic scale ln(α) with the absolute inverse temperature (1/ϑ). However, in cases with a large temperature range which eventually include more complex reaction processes, the functional relation between ln(α) and (1/ϑ) is nonlinear in the ‘Arrhenius plot’. In those cases, the monotone change of the nonlinear range in the ‘Arrhenius plot’ can be interpreted as a transient range between two approximately linear or constant regions. An extended application of the modified Arrhenius equation from Nakamura (1989) is presented in this study for this transient range. The introduced method was applied to describe the time-temperature equivalence in the relaxation analysis of restoring seal force of metal seals, which are used in lid-systems of transport and interim storage casks for radioactive materials. But, the method is widely valid and can be used for different objectives which are characterized by thermorheologically simple behavior with nonlinear sensitivity to inverse temperature.
KW - Metal seals
KW - TTS principle
KW - Arrhenius equation
KW - Non-linear Arrhenius behavior
KW - Relaxation analysis
KW - Seal force
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446759
UR - http://www.davidpublisher.org/index.php/Home/Article/index?id=33931.html
DO - https://doi.org/10.17265/1934-7359/2017.09.004
SN - 1934-7359
VL - 11
IS - 9
SP - 853
EP - 861
PB - David Publishing Company
CY - USA, NY 10989, Valley Cottage
AN - OPUS4-44675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Sascha
A1 - Münzenberger, Sven
A1 - Krebber, Katerina
T1 - Wavelength-scanning coherent OTDR for dynamic high strain resolution sensing
N2 - Distributed vibration sensing in optical fibers opened entirely new opportunities and penetrated various sectors from security to seismic monitoring. Here, we demonstrate a most simple and robust approach for dynamic strain measurement using wavelength-scanning coherent optical time domain reflectometry (C-OTDR). Our method is based on laser current modulation and Rayleigh backscatter shift correlation. As opposed to common single-wavelength phase demodulation techniques, also the algebraic sign of the strain change is retrieved. This is crucial for the intended applications in structural health monitoring and modal analysis. A linear strain response down to 47.5 pε and strain noise of 100 pε/√Hz is demonstrated for repetition rates in the kHz range. A field application of a vibrating bridge is presented. Our approach provides a cost-effective high-resolution method for structural vibration analysis and geophysical applications.
KW - Fiber optics sensors
KW - Optical time domain reflectometry
KW - Rayleigh Scattering
KW - Distributed acoustic sensing
KW - Distributed strain sensing
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448069
DO - https://doi.org/10.1364/OE.26.010573
SN - 1094-4087
VL - 26
IS - 8
SP - 10573
EP - 10588
PB - Optical Society of America
AN - OPUS4-44806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le, Quynh Hoa
A1 - Vestergaard, M.C.
A1 - Tamiya, E
T1 - Carbon-based nanomaterials in biomass-based fuel-fed fuel cells
N2 - Environmental and sustainable economical concerns are generating a growing interest in biofuels predominantly produced from biomass. It would be ideal if an energy conversion device could directly extract energy from a sustainable energy resource such as biomass. Unfortunately, up to now, such a direct conversion device produces insufficient power to meet the demand of practical applications. To realize the future of biofuel-fed fuel cells as a green energy conversion device, efforts have been devoted to the development of carbon-based nanomaterials with tunable electronic and surface characteristics to act as efficient metal-free electrocatalysts and/or as supporting matrix for metal-based electrocatalysts. We present here a mini review on the recent advances in carbon-based catalysts for each type of biofuel-fed/biofuel cells that directly/indirectly extract energy from biomass resources, and discuss the challenges and perspectives in this developing field
KW - Carbon-based nanomaterials
KW - Biofuel cells
KW - Biomass
KW - Carbon nanotubes
KW - Graphene
KW - Carbon nanodots
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428226
UR - http://www.mdpi.com/1424-8220/17/11/2587/htm
DO - https://doi.org/10.3390/s17112587
SN - 1424-8220
VL - 17
IS - 11
SP - 2587, 1
EP - 2587, 21
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-42822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Wilke, Olaf
A1 - Richter, Matthias
A1 - Brödner, Doris
T1 - Weiterentwicklung des Umweltzeichens Blauer Engel RAL-UZ 38 „Emissionsarme Produkte aus Holz und Holzwerkstoffen“ (UFOPLAN 3710 95 305 1)
N2 - In diesem Projekt wurde das Prüfverfahren für die chemischen Emissionen zum RAL-UZ 38 überarbeitet. Dabei stand die Bewertung der Prüfkammermessungen mit Hilfe des AgBB-Schemas im Vordergrund. Dafür wurden die Prüfkammerbedingungen angepasst. Mit Hilfe einer Emissionsdatenbasis wurden Anforderungen an die Emissionen der Umweltzeichenprodukte abgeleitet. Die Datenbasis bildeten vorhandene Emissionsdaten der Umweltzeichenprodukte und Messungen aktueller Produkte. Dazu wurden 10 Prüfkammermessungen an unterschiedlichen Möbelplatten durchgeführt. In Zusammenarbeit mit den Lizenznehmern, dem RAL und dem Umweltbundesamt wurde ein neues Verfahren für die Auswahl der Prüfmuster für die Emissionsmessung erarbeitet. Dieses vereinigt eine repräsentative Auswahl mit einer regelmäßigen Nachprüfung einzelner Möbel und/oder Bauteile. Zudem wurden Kriterien für die Überprüfung der Anforderungen an die Herkunft des Holzes aufgestellt. Für Bodenbeläge, Paneele und Türen aus Holz und Holzwerkstoffen für Innenräume wurde eine
neue Vergabegrundlage erschaffen (RAL-UZ 176).
KW - Blauer Engel
KW - Emissionsarme Materialien
KW - Prüfverfahren
KW - VOC-Emission
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427472
SN - 1862-4359
VL - 2017/31
SP - 1
EP - 46
PB - Umweltbundesamt (UBA)
AN - OPUS4-42747
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heitz, J.
A1 - Plamadeala, C.
A1 - Muck, M.
A1 - Armbruster, O.
A1 - Baumgartner, W.
A1 - Weth, A.
A1 - Steinwender, C.
A1 - Plessberger, H.
A1 - Kellermair, J.
A1 - Kirner, Sabrina V.
A1 - Krüger, Jörg
A1 - Bonse, Jörn
A1 - Guntner, A. S.
A1 - Hassel, A. W.
T1 - Femtosecond laser-induced microstructures on Ti substrates for reduced cell adhesion
N2 - Miniaturized pacemakers with a surface consisting of a Ti alloy may have to be removed after several years from their implantation site in the heart and shall, therefore, not be completely overgrown by cells or tissue. A method to avoid this may be to create at the surface by laser-ablation self-organized sharp conical spikes, which provide too little surface for cells (i.e., fibroblasts) to grow on. For this purpose, Ti-alloy substrates were irradiated in the air by 790 nm Ti:sapphire femtosecond laser pulses at fluences above the ablation threshold. The laser irradiation resulted in pronounced microstructure formation with hierarchical surface morphologies. Murine fibroblasts were seeded onto the laser-patterned surface and the coverage by cells was evaluated after 3–21 days of cultivation by means of scanning electron microscopy. Compared to flat surfaces, the cell density on the microstructures was significantly lower, the coverage was incomplete, and the cells had a clearly different morphology. The best results regarding suppression of cell growth were obtained on spike structures which were additionally electrochemically oxidized under acidic conditions. Cell cultivation with additional shear stress could reduce further the number of adherent cells.
KW - Laser Processing
KW - Femtosecond laser
KW - Titanium alloy
KW - Cell adhesion
KW - Anodic oxidation
KW - Pacemaker
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427681
UR - https://link.springer.com/article/10.1007/s00339-017-1352-0
DO - https://doi.org/10.1007/s00339-017-1352-0
SN - 0947-8396
SN - 1432-0630
VL - 123
IS - 12
SP - 734, 1
EP - 9
PB - Springer-Verlag
CY - Berlin
AN - OPUS4-42768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Boehm, Rainer
A1 - Heckel, Thomas
A1 - Spruch, W.
A1 - Beggerow, T.
T1 - Ultrasonic Phased Array Design Study for High Speed Axle Inspection using an Electronically Rotating Beam
N2 - For in-service inspections on wheelset axles with a hollow drilling, mechanized ultrasound inspection systems with single element probes are typically used. The ultrasonic testing in the zones close to the external surface of the railway axles can be realized from the inside of the bore hole, without demounting the wheelset and without dismantling the wheels and the brake discs. The testing system must be able to find flaws in the external surface of the hollow shafts, whose surface lies in the radial-radial plane, these are called transversal flaw. Presently testing systems are used, where scanning is realized in the circumferential direction by mechanical rotation of the probe system in the actual drilling. The phased array probe system, which is presented here, can carry out the rotation scan electronically. The scan can be carried out by simply moving the system forward and backwards through the drilling without mechanical rotation. Manipulation becomes simpler and the inspection time can be shortened considerably. The ultrasonic beam can be inclined exactly and be focused in the plane vertical to the specimen axis.
The probe is designed with help of indispensable simulations using especially designed software developed by BAM. The feasibility and the alignment between the simulated and experimental results were shown in earlier projects reported by Boehm et al. (2006) and Völz et al. (2012). The main task here is to optimize a probe for bore holes with a diameter of 65 mm with an increase in sensitivity and a high spatial resolution. This development will be carried out by use of extensive simulations and result in certain changes of the relevant probe parameters.
KW - Phased Array
KW - Ultrasound
KW - Axle inspection
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436230
DO - https://doi.org/10.1016/j.prostr.2017.07.001
VL - 2017
IS - 4
SP - 71
EP - 78
PB - Elsevier B.V.
AN - OPUS4-43623
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiggenhauser, Herbert
A1 - Köpp, Christian
A1 - Timofeev, Juri
A1 - Azari, H.
T1 - Controlled creating of cracks in concrete for non-destructive testing
N2 - The non-destructive assessment of cracks in concrete is a common task for which non-destructive evaluation solutions have been published. Primarily, these tests have been carried out on artificial cracks that have been created by using notches instead of natural cracks. This study evaluates a procedure designed to create reproducible and controlled cracks in concrete. The procedure is based on using expanding mortar in a series of blind holes. This is done in combination with carefully aligned reinforcement to guide the direction of the crack development. The depth of the crack is also controlled by reinforcement. Crack depth varies statistically in the range of the Maximum aggregate size (16 mm) used for concrete.
KW - Non-destructive testing of concrete
KW - Cracks
KW - Reference specimen
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457367
UR - https://rdcu.be/4IPN
DO - https://doi.org/10.1007/s10921-018-0517-x
SN - 0195-9298
SN - 1573-4862
VL - 37
IS - 3
SP - 67, 1
EP - 9
PB - Springer
CY - New York
AN - OPUS4-45736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Talebi, Elnaz
A1 - Korzen, Manfred
A1 - Espinós, A.
A1 - Hothan, Sascha
ED - Albero, Vicente
T1 - The effect of damage location on the performance of seismically damaged concrete filled steel tube columns at fire
N2 - In this paper, a nonlinear three-dimensional finite element (FE) model was developed and validated to study the effect of seismic damage location on the response of concrete filled tube (CFT) columns at fire after earthquakes. Three analyses were conducted consecutively in the modelling, namely, cyclic, thermal and structural. Results of the cyclic loading analysis comprising residual deformations were applied as the Initial condition to the thermal-stress model, replicating the seismic performance of column.
Following, a nonlinear sequentially coupled-thermal stress Analysis was carried out to investigate the fire response of CFT columns after the seismic event. Three damage scenarios were contemplated, considering any possible potential damages that could be generated by the earthquake loading on CFT columns. The accuracy of the proposed FE model was examined by comparing the numerical results with that of available tests on fire and cyclic loading. By means of the validated model, the performance of damaged CFT columns was then investigated under fire after earthquakes. The level of damage was assumed as a high damage level, presuming that the column reached 50% of ist lateral resistance while still maintaining its overall stability after the earthquake. The results were presented broadly, including the axial deformation history as well as the fire resistance time for CFT columns. To have a comprehensive insight on the influence of damage location in columns, the fire response of damaged specimens was compared with that of an intact one.
T2 - 12th International Conference on Advances in Steel-Concrete Composite Structures (ASCCS 2018)
CY - Valencia, Spain
DA - 27.06. 2018
KW - Fire after earthquake
KW - Concrete filled tube (CFT) column
KW - Finite element model
KW - Seismically damaged column
KW - Damage location
KW - Fire performance
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457694
SN - 978-84-9048-601-6
DO - https://doi.org/10.4995/ASCCS2018.2018.8534
SP - 835
EP - 842
PB - Editorial Universitat Politècnica de València
CY - València
AN - OPUS4-45769
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Thiel, Erik
A1 - Ahmadi, Samim
T1 - Lock-in Thermography using High-Power Laser Sources
N2 - Optical lock-in thermography is a completely contactless and very sensitive NDT technique. As an optical source of energy, incandescent lamps are most commonly used because they are relatively inexpensive and offer high irradiances at the test specimen. However, they are strongly restricted by their low modulation bandwidth with a maximum modulation frequency of only about 1 Hz. The use of high-power kilowattclass laser sources, e.g. diode laser arrays, pushes this constraint beyond 100 Hz. This allows for the exploration of the near-surface region of metals and layer systems with better and more accurate penetration depth and depth resolution. Moreover, these lasers are virtually free of any additional thermal radiation that could interfere with the “true” thermal response emitted from the heated sample. In turn, they can be easily used in a one-sided test configuration. We present current activities with kilowatt-class highpower laser sources for advanced lock-in thermography and focus on the application of laser arrays that offer a very high irradiation strength over a large sample area beyond the mentioned advantages.
T2 - 12th European Conference on Non-destructive Testing
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - Thermography
KW - Laser Thermography
KW - Lock-in Thermography
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454466
UR - http://cdn.ecndt2018.com/wp-content/uploads/2018/05/ecndt-0139-2018.pdf
SN - 978-91-639-6217-2
SP - ECNDT-0139-2018,1
EP - 7
AN - OPUS4-45446
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Burgholzer, P.
A1 - Berer, T.
A1 - Ziegler, Mathias
A1 - Thiel, Erik
A1 - Ahmadi, Samim
A1 - Gruber, J.
A1 - Mayr, G.
A1 - Hendorfer, G.
T1 - Blind structured illumination as excitation for super-resolution photothermal radiometry
N2 - Using an infrared camera for radiometric imaging allows the contactless temperature measurement of multiple surface pixels simultaneously. From the measured surface data, a sub-surface structure, embedded inside a sample or tissue, can be reconstructed and imaged when heated by an excitation light pulse. The main drawback in radiometric imaging is the degradation of the spatial resolution with increasing depth, which results in blurred images for deeper lying structures. We circumvent this degradation with blind structured illumination, combined with a non-linear joint sparsity reconstruction algorithm. The ground-breaking concept of super-resolution can be transferred from optics to thermographic imaging.
T2 - Conference QIRT 2018
CY - Berlin, Germany
DA - 25.06.2018
KW - Thermography
KW - Laser thermography
KW - Super resolution
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454506
SN - 978-3-940283-94-8
DO - https://doi.org/10.1080/17686733.2019.1655247
SP - We.3.A.2, 1
EP - 7
AN - OPUS4-45450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lugovtsova, Yevgeniya
A1 - Bulling, Jannis
A1 - Prager, Jens
A1 - Boller, C.
T1 - Efficient modelling of guided ultrasonic waves using the Scaled Boundary FEM towards SHM of composite pressure vessels
N2 - The Scaled Boundary Finite Element Method (SBFEM) is a semi-analytical method that shows promising results in modelling of guided ultrasonic waves. Efficiency and low computational cost of the method are achieved by a discretisation of the boundary of a computational domain only, whereas for the domain itself the analytical solution is used. By means of the SBFEM different types of defects, e.g. cracks, pores, delamination, corrosion, integrated into a structure consisting of anisotropic and isotropic materials can be modelled.
In this contribution, the SBFEM is used to analyse the propagation of guided waves in a structure consisting of an isotropic metal bonded to anisotropic carbon fibre reinforced material. The method allows appropriate wave types (modes) to be identified and to analyse their interaction with different defects. Results obtained are used to develop a structural health monitoring system for composite pressure vessels used in automotive and aerospace industries.
T2 - 9th European Workshop on Structural Health Monitoring (EWSHM)
CY - Manchester, UK
DA - 10.07.2018
KW - Structural Health Monitoring
KW - Pressure tanks
KW - Hydrogen storage
KW - Finite Element Modelling
KW - Composites
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454859
SP - 1
EP - 7
AN - OPUS4-45485
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Krankenhagen, Rainer
A1 - Röllig, Mathias
A1 - Heckel, Thomas
A1 - Brackrock, Daniel
A1 - Gaal, Mate
T1 - Quantification of impact damages in CFRP and GFRP structures with thermography and ultrasonics
N2 - The extent of damage caused by impacts in fibre reinforced composites depends on the energy of the impacts, on the velocity and the shape of the impacting body, on the material and structure of the composite and on the geometry of the structure. Here, mainly the thickness of the component is essential. The non-destructive evaluation of these damages can be carried out using both ultrasound and active thermography methods. A comparison of the detection sensitivity of these methods for the different damages is carried out in this paper depending on the fibre composite material used (CFRP and GFRP), the thickness of the material and the impact energy. The NDT methods used after the damage are supplemented by thermographic measurements with high temporal resolution, which were already recorded during the impact.
T2 - 14th Quantitative InfraRed Thermography Conference
CY - Berlin, Germany
DA - 25.06.2018
KW - Active thermography
KW - Passive thermography
KW - Ultrasonics
KW - CFRP
KW - GFRP
KW - Impact
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454952
UR - http://www.qirt.org/archives/qirt2018/papers/126.pdf
DO - https://doi.org/10.21611/qirt.2018.126
SP - 933
EP - 940
PB - DGZfP e. V.
AN - OPUS4-45495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schreier, Andy
A1 - Liehr, Sascha
A1 - Wosniok, Aleksander
A1 - Krebber, Katerina
T1 - Investigation on the influence of humidity on stimulated Brillouin backscattering in perfluorinated polymer optical fibers
N2 - In this paper perfluorinated graded-index polymer optical fibers are characterized with respect to the influence of relative humidity changes on spectral transmission absorption and Rayleigh backscattering. The hygroscopic and thermal expansion coefficient of the fiber are determined to be CHE = (7.4 +/- 0.1) 10^-6 %r.h.^-1 and CTE = (22.7 +/- 0.3) 10^-6 K^-1, respectively. The influence of humidity on the Brillouin backscattering power and linewidth are presented for the first time to our knowledge. The Brillouin backscattering power at a pump wavelength of 1319 nm is affected by temperature and humidity. The Brillouin linewidth is observed to be a function of temperature but not of humidity. The strain coefficient of the BFS is determined to be CS = (146.5 +/- 0.9) MHz/% for a wavelength of 1319 nm within a strain range from 0.1 % to 1.5 %. The obtained results demonstrate that the humidity-induced Brillouin frequency shift is predominantly caused by the swelling of the fiber over-cladding that leads to fiber straining.
KW - Brillouin
KW - Polymer optical fibre
KW - Humidity
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465932
DO - https://doi.org/10.3390/s18113952
SN - 1424-8220
VL - 18
IS - 11
SP - 3952, 1
EP - 12
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-46593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Uhlmann, E.
A1 - Hinzmann, D.
A1 - Kropidlowski, K.
A1 - Meier, P.
A1 - Prasol, L.
A1 - Woydt, Mathias
T1 - Increased tool performance with niobium carbide based cutting materials in dry cylindrical turning
N2 - In the present work it was shown that in contrast to WC tools NbC cutting tools show constant material removal VW at increased cutting speed vc combined with a higher process reliability.
KW - Niobium carbide (NbC)
KW - Tungsten carbide (WC)
KW - Tool wear
KW - Cylindrical turning
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465968
DO - https://doi.org/10.1016/j.procir.2018.08.238
SN - 2212-8271
VL - 77
SP - 541
EP - 544
PB - Elsevier
AN - OPUS4-46596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Wendland, Saskia
A1 - Gaal, Mate
T1 - Airborne testing of molded polymer compounds
N2 - Modern and energy-efficient materials are essential for innovative designs for aerospace and automotive industries. Current technologies for rapid manufacturing such as additive manufacturing and liquid composite moulding by polymer Extrusion allow innovative ways of creating robust and lightweight constructions. Commercially available printing devices often use polylactide (PLA) or acrylonitrile butadiene styrene (ABS) as raw material. Therefore, parameters like the infill ratio, influencing the ability to resist mechanical stress, may have a beneficial impact on the lifetime of components.
These manufacturing technologies require a good knowledge about materials and even adapted non-destructive testing technologies and methods. Airborne ultrasonic testing has beneficial advantages for testing those lightweight constructions. It is a contact-free testing method, which does not require a liquid couplant. Therefore, it allows fast test cycles without any unwanted alternations of the material properties due to interactions with any coupling liquid. This contribution deals with the characterisation of printed specimens based on PLA by using airborne ultrasound and presents the current edge of non-destructive testing and evaluation using airborne ultrasonic transducers. The specimens, manufactured by polymer extrusion, are printed as thin plates. The infill ratio, as well as the material thickness, were varied to model density imperfections with different geometric shapes and properties. For better understanding of the limits of airborne ultrasonic testing in transmission, we compared own-developed transducers based on different physical principles: on ferroelectrets, on the thermoacoustic effect, as well as a new type of transducers based on gas discharges.
T2 - 10th International Symposium on NDT in Aerospace
CY - Dresden, Germany
DA - 24.10.2018
KW - Air-coupled ultrasonic testing
KW - Polymer
KW - Plasma acoustics
KW - Gas discharges
KW - Atmospheric pressure plasma
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465609
VL - 168
SP - Th.6.C.1, 1
EP - 7
AN - OPUS4-46560
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Pérez Alonso, M.
A1 - Albarrán Sanz, J.
A1 - Dinkel, M.
A1 - Heckel, Thomas
A1 - Kotschate, Daniel
A1 - Cabeza, Sandra
A1 - Senaneuch, J.
A1 - Heikkila, I.
A1 - Toscanelli, O.
T1 - A novel approach for rating fatigue-initiating inclusions in highly demanding steel (INCAFAT)
N2 - INCAFAT project aimed to improve existing fatigue damage models by establishing the most suitable combination of measurement techniques to characterise harmful inclusion populations in highly demanding steels. The different inclusion assessments carried out confirm that, chemical composition, secondary metallurgy and manufacturing route affect content, nature, size and shape of inclusions. According to the FEM model, inclusions produce an alteration of the stress field in their surrounding region, which can promote a fatigue failure. Experimental work on fatigue testing has demonstrated that depending on the stressed direction fatigue failures in highly demanding steels could be produced by different types of inclusions. Fractography analyses confirmed that meso-inclusions harmful in fatigue cannot be rated by standard methods, nor 10 MHz ultrasonic testing (macro) or micro-cleanness assessments. The necessity of rating these meso-inclusions has led to critical evaluation of Extreme Value Analysis according to ASTM E2283-08 and the development of high frequency immersion ultrasonic testing. EVA methodology based on inclusion width can be applied reliably when principal stress is parallel to the rolling direction. On the contrary, if inclusions are testing in the elongated directions its fails. On the other hand, the guidelines and recommendations for high frequency ultrasonic testing have been compiled in a new European standard draft. This method based on focal beam probes and high-resolution devices is able to provide information on meso-inclusion distribution.
KW - Material characterisation
KW - Non-destructive testing
KW - Ultrasonic testing
KW - Cleanliness
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479219
UR - https://publications.europa.eu/en/publication-detail/-/publication/6bd25206-316a-11e8-b5fe-01aa75ed71a1/language-en/format-PDF/source-68610160
SN - 978-92-79-76985-6
DO - https://doi.org/10.2777/473350
SN - 1831-9424
SN - 1018-5593
SP - 1
EP - 154
AN - OPUS4-47921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tukhmetova, Dariya
A1 - Langhammer, Nicole
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Online Isotope Analysis of Sulfur in Proteins via Capillary Electrophoresis Coupled With Multicollector ICP‐MS (CE/MC‐ICP‐MS): A Proof of Concept Study
N2 - Isotope ratio analysis of sulfur in biological samples using inductively coupled plasma-mass spectrometry (ICP-MS) has gained significant interest for applications in quantitative proteomics. Advancements like coupling separation techniques with multicollector ICP-MS (MC-ICP-MS) enhance the throughput of species-specific sulfur isotope ratio measurements, fostering new avenues for studying sulfur metabolism in complex biological matrices. This proof-of-concept study investigates the feasibility of online CE/MC-ICP-MS for directly analyzing sulfur isotope ratios in proteins (albumin). Leveraging our previous work on the applicability of CE/ICP-MS for quantifying sulfur-containing biological molecules, we explore its potential for sulfur isotope analysis. Our results demonstrate that direct analysis of sulfur isotopes in albumin protein using online capillary electrophoresis MC-ICP-MS (CE/MC-ICP-MS) eliminates the need for laborious pretreatment steps, while yielding isotope ratios comparable to the reference values. Although initial precision can be improved through further system optimization and protein injection techniques, this approach paves the way for future analysis of mixtures of various biological compounds in, for example, clinical diagnosis studies.
KW - Isotope analysis
KW - Sulfur
KW - CE/MC-ICP-MS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612439
DO - https://doi.org/10.1002/elps.202400128
SN - 0173-0835
SP - 1
EP - 6
PB - Wiley-Blackwell
CY - Weinheim
AN - OPUS4-61243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - Curran, Maurice
A1 - Campbell, Carelyn E.
A1 - Dima, Alden A.
A1 - Birkholz, Henk
A1 - Lau, June W.
T1 - Natural Language Processing-Driven Microscopy Ontology Development
N2 - AbstractThis manuscript describes the accelerated development of an ontology for microscopy in materials science and engineering, leveraging natural language processing (NLP) techniques. Drawing from a comprehensive corpus comprising over 14 k contributions to the Microscopy and Microanalysis conference series, we employed two neural network-based algorithms for NLP. The goal was to semiautomatically create the Microscopy Ontology (MO) that encapsulates and interconnects the terminology most frequently used by the community. The MO, characterized by its interlinked entities and relationships, is designed to enhance the quality of user query results within NexusLIMS. This enhancement is facilitated through the concurrent querying of related terms and the seamless integration of logical connections.
KW - Microscopy Ontology
KW - Knowledge Representation
KW - Semantic Interoperability
KW - Natural Language Processing
KW - Ontology Development
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616942
DO - https://doi.org/10.1007/s40192-024-00378-y
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-61694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Yue
A1 - Colnaghi, Timoteo
A1 - Gong, Yilun
A1 - Zhang, Huaide
A1 - Yu, Yuan
A1 - Wei, Ye
A1 - Gan, Bin
A1 - Song, Min
A1 - Marek, Andreas
A1 - Rampp, Markus
A1 - Zhang, Siyuan
A1 - Pei, Zongrui
A1 - Wuttig, Matthias
A1 - Ghosh, Sheuly
A1 - Körmann, Fritz
A1 - Neugebauer, Jörg
A1 - Wang, Zhangwei
A1 - Gault, Baptiste
T1 - Machine learning‐enabled tomographic imaging of chemical short‐range atomic ordering
N2 - In solids, chemical short‐range order (CSRO) refers to the self‐organization of atoms of certain species occupying specific crystal sites. CSRO is increasingly being envisaged as a lever to tailor the mechanical and functional properties of materials. Yet quantitative relationships between properties and the morphology, number density, and atomic configurations of CSRO domains remain elusive. Herein, it is showcased how machine learning‐enhanced atom probe tomography (APT) can mine the near‐atomically resolved APT data and jointly exploit the technique's high elemental sensitivity to provide a 3D quantitative analysis of CSRO in a CoCrNi medium‐entropy alloy. Multiple CSRO configurations are revealed, with their formation supported by state‐of‐the‐art Monte‐Carlo simulations. Quantitative analysis of these CSROs allows establishing relationships between processing parameters and physical properties. The unambiguous characterization of CSRO will help refine strategies for designing advanced materials by manipulating atomic‐scale architectures.
KW - Chemical short-range order (CSRO)
KW - Atom probe tomography (APT)
KW - Machine learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623777
DO - https://doi.org/10.1002/adma.202407564
SN - 1521-4095
VL - 36
IS - 44
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-62377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Mohring, Wencke
A1 - Wolf, Marcus
T1 - The insignificant improvement of corrosion and corrosion fatigue behavior in geothermal environment applying Boehmit coatings on high alloyed steels
N2 - The efficacy of alumina-sol based coatings in a water-free atmosphere at high temperatures suggests a potential solution for enhancing the corrosion resistance of high-alloyed steels in Carbon Capture and Storage (CCS) environments. In this study, coupons of X20Cr13, designed for use as injection pipes with 13% Chromium and 0.20% Carbon (1.4021, AISI 420), were sol-gel coated with water and ethanol-based alumina. These coated coupons were then exposed to CO2-saturated saline aquifer water, simulating conditions in the Northern German Basin, for 1000 h at ambient pressure and 60 °C. Corrosion fatigue experiments were also conducted using specimens of X5CrNiMoCuNb16-4 (1.4542, AISI 630), a suitable candidate for geothermal applications, to assess the impact of the ethanol-based coating on the number of cycles to failure at different stress amplitudes. Unfortunately, the coating exhibited early spallation, resulting in corrosion kinetics and corrosion fatigue data identical to those of uncoated specimens. Consequently, the initially promising Boehmit coating is deemed unsuitable for CCS applications and further research therefore not advisable.
KW - Alumina coating
KW - High alloyed steel
KW - Pitting
KW - Surface corrosion
KW - CO2
KW - Pipeline
KW - Corrosion
KW - CCS
KW - CO2-storage
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623786
DO - https://doi.org/10.3390/app14041575
SN - 2076-3417
VL - 14
IS - 4
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-62378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vlach, Tomáš
A1 - Řepka, Jakub
A1 - Hájek, Jakub
A1 - Pošta, Jan
A1 - Fürst, Richard
A1 - Hájek, Petr
T1 - Shear Capacity of Hollow High-Performance Concrete Beams with Cross-Wound Carbon Fiber-Reinforced Polymer Reinforcement
N2 - This paper introduces cross-wound CFRP shear reinforcement of hollow HPC beams. The CFRP reinforcement was manufactured in the form of a square tubular mesh from carbon rovings oriented at ±45° from the longitudinal axis. The shear reinforcement was made in two variants from carbon yarns with linear densities of 1600 and 3700 tex. Tensile reinforcement made of BFRP bars was positioned directly around the hollow core and was used as a platform for manual winding of the shear reinforcement. The hollow beams were subjected to a three-point bending test with four configurations of the tensile BFRP reinforcement for better evaluation of the effect of the shear reinforcement under different conditions. The 1600 tex shear reinforcement increased the ultimate flexural strength by at least 89% compared to specimens without any shear reinforcement. The 3700 tex shear reinforcement yielded slightly better results in most cases but was not utilized to its full shear capacity as these specimens always failed in shear due to the delamination of the concrete matrix from the shear reinforcement. There was too much reinforcement in the beam cross-section.
KW - Hollow concrete beam
KW - Shear reinforcement
KW - Composite reinforcement
KW - Woven reinforcement
KW - Cross-wound reinforcement
KW - Fiber-reinforced polymer
KW - High-performance concrete
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623868
DO - https://doi.org/10.3390/polym17010075
SN - 2073-4360
VL - 17
IS - 1
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-62386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arıkan, Muzaffer
A1 - Demir, Tuğçe Kahraman
A1 - Yıldız, Zeynep
A1 - Nalbantoğlu, Özkan Ufuk
A1 - Korkmaz, Nur Damla
A1 - Yılmaz, Nesrin H.
A1 - Şen, Aysu
A1 - Özcan, Mutlu
A1 - Muth, Thilo
A1 - Hanoğlu, Lütfü
A1 - Yıldırım, Süleyman
T1 - Metaproteogenomic analysis of saliva samples from Parkinson's disease patients with cognitive impairment
N2 - Cognitive impairment (CI) is very common in patients with Parkinson’s Disease (PD) and progressively develops on a spectrum from mild cognitive impairment (PD-MCI) to full dementia (PDD). Identification of PD patients at risk of developing cognitive decline, therefore, is unmet need in the clinic to manage the disease. Previous studies reported that oral microbiota of PD patients was altered even at early stages and poor oral hygiene is associated with dementia. However, data from single modalities are often unable to explain complex chronic diseases in the brain and cannot reliably predict the risk of disease progression. Here, we performed integrative metaproteogenomic characterization of salivary microbiota and tested the hypothesis that biological molecules of saliva and saliva microbiota dynamically shift in association with the progression of cognitive decline and harbor discriminatory key signatures across the spectrum of CI in PD. We recruited a cohort of 115 participants in a multi-center study and employed multi-omics factor analysis (MOFA) to integrate amplicon sequencing and metaproteomic analysis to identify signature taxa and proteins in saliva. Our baseline analyses revealed contrasting interplay between the genus Neisseria and Lactobacillus and Ligilactobacillus genera across the spectrum of CI. The group specific signature profiles enabled us to identify bacterial genera and protein groups associated with CI stages in PD. Our study describes compositional dynamics of saliva across the spectrum of CI in PD and paves the way for developing non-invasive biomarker strategies to predict the risk of CI progression in PD.
KW - Cognitive impairment (CI)
KW - Parkinson’s disease (PD)
KW - Metaproteogenomic analysis
KW - Saliva sample
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624228
DO - https://doi.org/10.1038/s41522-023-00452-x
SN - 2055-5008
VL - 9
IS - 1
SP - 1
EP - 10
PB - Nature Publ. Group
CY - London
AN - OPUS4-62422
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kärcher, Victor
A1 - Reiker, Tobias
A1 - da Costa, Pedro F.G.M.
A1 - de Camargo, Andrea S.S.
A1 - Zacharias, Helmut
T1 - Quantum control in size selected semiconductor quantum dot thin films
N2 - We introduce a novel technique for coherent control that employs resonant internally generated fields in CdTe quantum dot (QD) thin films at the L-point. The bulk band gap of CdTe at the L-point amounts to 3.6 eV, with the transition marked by strong Coulomb coupling. Third harmonic generation (λ3 = 343 nm, hν = 3.61 eV) for a fundamental wavelength of λ 1 = 1,030 nm is used to control quantum interference of three-photon resonant paths between the valence and conduction bands. Different thicknesses of the CdTe QDs are used to manipulate the phase relationship between the external fundamental and the internally generated third harmonic, resulting in either suppression or strong enhancement of the resonant third harmonic, while the nonresonant components remain nearly constant. This development could pave the way for new quantum interference–based applications in ultrafast switching of nanophotonic devices.
KW - Nonlinear nanophotonics
KW - Quantum interference
KW - Third harmonic
KW - Coherent control
KW - Thin films
KW - Quantum dots
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625859
DO - https://doi.org/10.1515/nanoph-2024-0529
VL - 14
IS - 2
SP - 229
EP - 239
PB - Walter de Gruyter GmbH
AN - OPUS4-62585
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn Setsuko
A1 - Ravaro, Leandro Piaggi
A1 - Brambilla, Gabriel
A1 - Maia, Lauro June Queiroz
A1 - Reza Dousti, Mohammad
A1 - de Camargo, Andrea Simone Stucchi
T1 - Upconverting Nanoparticles and Cu(I) Complex-Based Platform for Oxygen Sensing, Thermometry, and Emission Color Tuning
N2 - Multifunctional nanoplatforms combine different material properties to meet a wide range of applications, allowing highly customizable systems. In this rapidly advancing research field, we introduce a multifunctional nanomaterial based on the synergy between Tm3+-doped upconverting nanoparticles (UCNPs) and a Cu(I) complex (CuCom). This material is designed for oxygen sensing, optical thermometry, and emission color tuning. In various concentrations, the CuCom complex was electrostatically integrated into a mesoporous silica shell surrounding the core UCNPs (UCNP@mSiO2). The optimized system, UCNP@mSiO2@CuCom-10, was evaluated for different applications. Due to the spectral overlap between the CuCom absorption and the nanoparticles emission, excitation at 980 nm allows most of the UV-blue emission output from the UCNPs to be transferred to the CuCom via luminescent resonance energy transfer (LRET), producing red emission from the molecule. The remaining Tm3+ emission enables optical thermometry, while CuCom’s sensitivity to molecular oxygen supports its application in gas sensing. In upconversion mode, the nanoplatform achieved a Stern−Volmer constant for O2 sensing of 1.64 and demonstrated thermometric relative sensitivities of 0.9% and 1% K−1 at room temperature, with a linear response from 193 to 373 K. Additionally, the emission color of UCNP@mSiO2@CuCom-10 can be tuned from blue to white and yellow, by varying the excitation and temperature, adding further functionality to the system. This multifunctional platform suggests promising applications in biology, medicine, and environmental monitoring.
KW - M
KW - O2 sensing
KW - Upconversion
KW - Luminescence resonance energy transfer (LRET)
KW - Optical thermometry
KW - Mesoporous silica shell
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625869
SN - 2574-0970
DO - https://doi.org/10.1021/acsanm.4c06351
VL - 8
SP - 854
EP - 862
PB - American Chemical Society (ACS)
AN - OPUS4-62586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Nathalie
A1 - Karamitsou, Venetia
A1 - Giegerich, Clemens
A1 - Sadeghi, Afshin
A1 - Lücke, Moritz
A1 - Wagenhuber, Britta
A1 - Kister, Alexander
A1 - Rehberg, Markus
T1 - Building virtual patients using simulation-based inference
N2 - In the context of in silico clinical trials, mechanistic computer models for pathophysiology and pharmacology (here Quantitative Systems Pharmacology models, QSP) can greatly support the decision making for drug candidates and elucidate the (potential) response of patients to existing and novel treatments. These models are built on disease mechanisms and then parametrized using (clinical study) data. Clinical variability among patients is represented by alternative model parameterizations, called virtual patients. Despite the complexity of disease modeling itself, using individual patient data to build these virtual patients is particularly challenging given the high-dimensional, potentially sparse and noisy clinical trial data. In this work, we investigate the applicability of simulation-based inference (SBI), an advanced probabilistic machine learning approach, for virtual patient generation from individual patient data and we develop and evaluate the concept of nearest patient fits (SBI NPF), which further enhances the fitting performance. At the example of rheumatoid arthritis where prediction of treatment response is notoriously difficult, our experiments demonstrate that the SBI approaches can capture large inter-patient variability in clinical data and can compete with standard fitting methods in the field. Moreover, since SBI learns a probability distribution over the virtual patient parametrization, it naturally provides the probability for alternative parametrizations. The learned distributions allow us to generate highly probable alternative virtual patient populations for rheumatoid arthritis, which could potentially enhance the assessment of drug candidates if used for in silico trials.
KW - Simulation-based inference
KW - Machine learning
KW - Artificial intelligence
KW - Virtual patients
KW - Pathophysiology
KW - Pharmacology
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626050
DO - https://doi.org/10.3389/fsysb.2024.1444912
SN - 2674-0702
VL - 4
SP - 1
EP - 11
PB - Frontiers Media SA
AN - OPUS4-62605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weiss, Daniel
A1 - Asna Ashari, Parsa
A1 - Blind, Knut
T1 - Exploring the fuel-cell technological innovation system: Technology interactions in the mobility sector
N2 - With the rise of alternative sustainable powertrain technologies, the mobility paradigm has undergone fundamental changes in recent years. In the wake of the ongoing transition of the road-vehicle sector, fuel-cell vehicles (FCVs) have received increased political attention. However, they constitute only a tiny fraction of total road vehicles nowadays and still face competition from other powertrain technologies. Therefore, this study specifically focuses on how the focal technological innovation system of FCVs is influenced by the emerging electric vehicles (EVs) and established internal combustion engine vehicles (ICEVs) as its context structures. To this end, our time-series vector error correction models analyze the short- and long-run causalities between our focal TIS and its context structures. Using publications, patents, and standards as quantitative TIS indicators, we analyze the modes of technology interaction between FCVs and EVs and FCVs and ICEVs to determine the life-cycle phase of our focal FCV-TIS in more depth. Our results demonstrate that the FCV-TIS is in its formative phase based on the dominance of the EV and ICEV context structures. As policy implications, we derive application-sensitive technology policies that combine the benefits of each mobility technology toward the sustainable transition of the mobility sector.
KW - Technological innovation system (TIS)
KW - Technology interaction
KW - TIS-context relations
KW - Fuel-cell vehicles
KW - Electric vehicles
KW - Internal combustion engine vehicles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626599
DO - https://doi.org/10.1016/j.trip.2024.101107
SN - 2590-1982
VL - 25
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ladu, Luana
A1 - Morone, P.
T1 - Sustainability assessments of bio-based products: From research to practice (and standards)☆
N2 - The transition from a linear, fossil-based economy to a circular, bio-based economy is needed in order to achieve climate neutrality by 2050. However, it is important to ensure that the bio-based economy delivers the expected environmental and social impacts, by respecting and implementing sustainability principles. One effective way to reduce uncertainty regarding bio-based product properties and benefits is through the use of sustainability standards, certification schemes, and ecolabels. These measures can play a significant role in advancing the transition to a sustainable, circular bio-based economy. They provide a solid foundation for assessing sustainability of “green” products and initiatives and contribute greatly to building trust in products among consumers, providing a reliable framework for sevaluation. To measure the sustainability of bio-based products, several robust and reliable tools are under development, gathering evidence from research and collaborative efforts of several European projects.
KW - Bioeconomy
KW - Sustainability Assessment
KW - Standards
KW - Certifications
KW - Ecolabels
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623576
DO - https://doi.org/10.1016/j.socimp.2024.100041
VL - 3
SP - 1
EP - 4
PB - Elsevier Ltd.
AN - OPUS4-62357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valentini, Martino
A1 - De Almeida, Olivier
A1 - Kakkonen, Markus
A1 - Kalinka, Gerhard
A1 - Dorigato, Andrea
A1 - Kallio, Pasi
A1 - Fredi, Giulia
T1 - Effect of fiber surface state on the thermomechanical and interfacial properties of in situ polymerized polyamide 6/basalt fiber composites
N2 - This study investigates the thermomechanical properties and interfacial adhesion of novel in-situ polymerized anionic polyamide 6 (aPA6) composites reinforced with basalt fibers (BF). The impact of different BF surface states - as-received (BFa), ethanol-washed (BFw), and thermally desized (BFu) on composite performance is examined through a comprehensive approach. For the first time, anionic PA6/BF composites with very low residual monomer content were successfully produced via thermoplastic resin transfer molding (tRTM). The PA6/BFw composites exhibited the highest interlaminar/interfacial shear strength in short beam shear test (52 ±8 MPa) and fiber push out test (34 ± 11 MPa) tests. Fiber microdebonding test, performed only on PA6/BFw, yielded a low interfacial shear strength (12 ± 4 MPa), which was attributed to droplet porosity resulting from concurrent polymerization and crystallization. Thermal desizing significantly deteriorated interfacial strength (19.6 ± 1.2 MPa in short beam shear test). This multi-technique characterization provides insights into optimizing the fiber–matrix adhesion in these advanced thermoplastic composites.
KW - Anionic Polyamide 6
KW - Reactive thermoplastics
KW - Basalt fibers
KW - Microdebonding
KW - Fiber push out
KW - Short beam shear test
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623596
DO - https://doi.org/10.1016/j.compositesa.2024.108681
SN - 1878-5840
VL - 190
SP - 1
EP - 15
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-62359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kozachynskyi, Volodymyr
A1 - Hoffmann, Christian
A1 - Esche, Erik
T1 - Why fixing alpha in the NRTL model might be a bad idea – Identifiability analysis of binary vapor-liquid equilibria
N2 - New vapor-liquid equilibrium (VLE) data are continuously being measured and new parameter values, e.g., for the nonrandom two-liquid (NRTL) model are estimated and published. The parameter α, the nonrandomness parameter of NRTL, is often not estimated but is heuristically fixed to a constant value based on the involved components. This can be seen as a manual application of a (subset selection) regularization method. In this work, the practical parameter identifiability of the NRTL model for describing the VLE is analyzed. It is shown that fixing α is not always a good decision and sometimes leads to worse prediction properties of the final parameter estimates. Popular regularization techniques are compared and Generalized Orthogonalization is proposed as an alternative to this heuristic. In addition, the sequential Optimal Experimental Design and Parameter Estimation (sOED-PE) method is applied to study the influence of the regularization methods on the performance of the sOED-PE loop.
KW - NRTL
KW - VLE
KW - Nonlinear programming
KW - Model-based optimal experimental design
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623605
DO - https://doi.org/10.1016/j.ces.2024.121122
VL - 305
SP - 1
EP - 18
PB - Elsevier Ltd.
AN - OPUS4-62360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cunningham, Patrick
A1 - Wang, L.
A1 - Kane, S.
A1 - Kim, A.
A1 - Jenkins, B. M.
A1 - Miller, S. A.
T1 - Lifecycle implications and mechanical properties of carbonated biomass ashes as carbon-storing supplementary cementitious materials
N2 - Methods to sequester and store atmospheric CO2 are critical to combat climate change. Alkaline-rich bioashes are potential carbon fixing materials. This work investigates potential co-benefits from mineralizing carbon in biomass ashes and partially replacing high embodied greenhouse gas (GHG) Portland cement (PC) in cement-based materials with these ashes. Specifically, rice hull ash (RHA), wheat straw ash (WSA), and sugarcane bagasse ash (SBA) were treated to mineralize carbon, and their experimental carbon content was compared to modeled potential carbonation. To understand changes in the cement-based storage materials, mortars made with CO2-treated WSA and RHA were experimentally compared to PC-only mortars and mortars made with ashes without prior CO2 treatment. Life cycle assessment methodology was applied to understand potential reductions in GHG emissions. The modeled carbonation was ∼18 g-CO2/kg-RHA and ∼180 g-CO2/kg-WSA. Ashes oxidized at 500 °C had the largest measured carbon content (5.4 g-carbon/kg-RHA and 35.3 g-carbon/kg-WSA). This carbon appeared to be predominantly residual from the biomass. Isothermal calorimetry showed RHA-PC pastes had similar heat of hydration to PC-pastes, while WSA-PC pastes exhibited an early (at ∼1.5 min) endothermic dip. Mortars with 5 % and 15 % RHA replacement had 1–12 % higher compressive strength at 28 days than PC-only mortars, and milled WSA mortars with 5 % replacement had 3 % higher strength. A loss in strength was noted for the milled 15 % WSA, the CO2-treated 5 %, and the 15 % WSA mortars. Modeled reductions in GHG emissions from CO2-treated ashes were, however, marginal (<1 %) relative to the untreated ashes.
KW - CO2 sequestration
KW - CO2 storage
KW - Biomass ash
KW - Supplementary cementitious materials
KW - Concrete
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626959
DO - https://doi.org/10.1016/j.biombioe.2025.107772
SN - 1873-2909
VL - 197
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asante, Bright
T1 - Optimized mix design and fire resistance of geopolymer recycled aggregate concrete under elevated temperatures
N2 - This study investigates the performance of fly ash-based geopolymer recycled aggregate concrete (GRAC) as a sustainable alternative to Ordinary Portland Cement (OPC) concrete, focusing on its compressive strength and behavior under high-temperature exposure (150 ◦C, 300 ◦C, 600 ◦C, and 900 ◦C). The research emphasizes the use of 100 % recycled concrete aggregates as a replacement for natural aggregates, with samples cured at ambient conditions and at 60 ◦C in an oven. Key factors, including water content and curing conditions, were evaluated to determine their influence on compressive strength and thermal stability. Results indicate that water content is the primary factor governing compressive strength, while recycled aggregates contribute to a secondary but notable effect. GRAC maintained up to 65 % of its initial strength after exposure to 600 ◦C, though strength degradation and severe cracking occurred at 900 ◦C. Oven-cured samples showed fewer surface cracks but experienced slightly higher mass loss than room-cured coun-terparts. This study highlights the potential of GRAC as an environmentally friendly material capable of withstanding moderate thermal conditions, providing significant contributions to green construction practices and the reuse of construction and demolition waste.
KW - Geopolymer
KW - Recycled aggregate concrete
KW - Elevated temperature
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627071
DO - https://doi.org/10.1016/j.cscm.2025.e04401
SN - 2214-5095
VL - 22
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-62707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Tobias
A1 - Mensing, Friedrich
A1 - Kruschwitz, Sabine
T1 - Estimation of cement content in concrete by spatially resolved laser induced breakdown spectroscopy
N2 - The cement content in concrete significantly influences critical properties such as durability, permeability, strength, and workability. Traditional methods for estimating the cement content face limitations. These include the need for comprehensive chemical and solubility knowledge, extensive sample preparation, and their time-consuming and destructive nature. This study investigates the application of laser-induced breakdown spectroscopy (LIBS) as an alternative method. It involves probing concrete samples with high spatial resolution and analyzing the resultant spectra. The methodology is first tested on mesoscale concrete models to assess limitations and inherent errors. Subsequently, the methodology is applied to actual concrete samples with varying cement content and aggregate size distributions. The results demonstrate a promising accuracy, with an average relative error of approximately 8%. This paper offers a comprehensive evaluation of the method's advantages, limitations, and factors influencing its practical applicability in field conditions.
KW - LIBS
KW - Spectroscopy
KW - Cement content
KW - Elemental mapping
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620112
DO - https://doi.org/10.1016/j.cemconres.2024.107714
SN - 1873-3948
VL - 189
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-62011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alem, Sayed Ali Ahmad
A1 - Sabzvand, Mohammad Hossein
A1 - Govahi, Parnian
A1 - Poormehrabi, Pooria
A1 - Azar, Mahdi Hasanzadeh
A1 - Siouki, Sara Salehi
A1 - Rashidi, Reza
A1 - Angizi, Shayan
A1 - Bagherifard, Sara
T1 - Advancing the next generation of high-performance metal matrix composites through metal particle reinforcement
N2 - Metal matrix composites (MMCs) offer asignificant boost to achieve a wide range of advanced mechanical properties and improved performance for a variety of demanding applications. The addition of metal particles as reinforcement in MMCs is an exciting alternative to conventional ceramic reinforcements, which suffer from numerous shortcomings. Over the last two decades, various categories of metal particles, i.e., intermetallics, bulk metallic glasses, high-entropy alloys, and shape memory alloys, have become popular as reinforcement choices for MMCs. These groups of metal particles offer a combination of outstanding physico-mechanical properties leading to unprecedented performances; moreover, they are significantly more compatible with the metal matrices compared to traditional ceramic reinforcements. In this review paper, the recent developments in MMCs are investigated. The importance of understanding the active mechanisms at the interface of the matrix and the reinforcement is highlighted. Moreover, the processing techniques required to manufacture high-performance MMCs are explored identifying the potential structural and functional applications. Finally, the potential advantages and current challenges associated with the use of each reinforcement category and the future developments are critically discussed. Based on the reported results, the use of metal particles as reinforcement in MMCs offers a promising avenue for the development of advanced materials with novel mechanical properties. Further progress requires more in-depth fundamental research to realize the active reinforcing mechanisms at the atomic level to precisely identify, understand, and tailor the properties of the integrated composite materials.
KW - Intermetallic
KW - Composite
KW - Metal matrix composite
KW - Interface
KW - High entropy alloy
KW - Bulk metallic glass
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620730
DO - https://doi.org/10.1007/s42114-024-01057-4
SN - 2522-0128
VL - 8
IS - 1
SP - 1
EP - 68
PB - Springer Nature
AN - OPUS4-62073
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Christensen, J. B.
A1 - Jørgensen, A. A.
A1 - Vandborg, M. H.
A1 - Thomas, P. J.
A1 - Lu, Xin
A1 - Failleau, G.
A1 - Eisermann, R.
A1 - Grüner-Nielsen, L.
A1 - Balslev-Harder, D.
A1 - Lassen, M.
A1 - Krenek, S.
T1 - Fiber-artefact methodology and calibration framework for Brillouin-based fiber sensing
N2 - We propose, and demonstrate, the use of a fiber-optical measurement artefact as a metrological tool for traceable distance calibration of distributed optical fiber sensors. The constructed fiber artefact consists of a lead-in fiber coupled to a fiber loop using a 3-dB coupler and is used to calibrate both a home-build Brillouin-OTDR setup and a custom version of a commercial Brillouin-OTDR interrogator build for distributed temperature sensing. For both interrogators, we demonstrate distance calibrations with 1-meter uncertainty (k=1) in the offset length and 0.1 % (1 m/km) uncertainty (k = 1) in the distance scale factor. In addition, it is shown that the fiber artefact can be used to assess undesired distance-dependent measurement biases.
KW - Distributed temperature sensing
KW - Metrology
KW - Distributed optical fiber sensing
KW - Brillouin optical time-domain reflectrometry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618853
DO - https://doi.org/10.1364/OE.544659
SN - 1094-4087
VL - 32
IS - 26
SP - 45483
EP - 45493
PB - Optica Publishing Group
AN - OPUS4-61885
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shafiey, Hassan
A1 - Gogol-Döring, Andreas
A1 - McMahon, Dino Peter
A1 - Doublet, Vincent
A1 - Disayathanoowat, Terd
A1 - Paxton, Robert J.
T1 - A new variant of slow bee paralysis virus revealed by transcriptome analysis
N2 - Using NGS data from an RNA-seq library, we reveal a novel variant of slow bee paralysis virus (SBPV) in a pooled sample of adult honey bees (Apis mellifera) collected in southwest Germany. We provide its sequence (NCBI Accession No. PP100271) and demonstrate that it is infective for adult honey bees by feeding.
KW - SBPV
KW - Apis mellifera
KW - +ss RNA virus
KW - Iflaviridae
KW - Transmission
KW - NGS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620900
DO - https://doi.org/10.1080/00218839.2024.2425912
SP - 1
EP - 5
PB - Taylor & Francis
AN - OPUS4-62090
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rasool, Muhammad Hammad
A1 - Ahmad, Maqsood
A1 - Siddiqui, Numair Ahmed
A1 - Junejo, Aisha Zahid
T1 - Eco-friendly drilling fluid: Calcium chloride-based natural deep eutectic solvent (NADES) as an all-rounder additive
N2 - Designing an effective drilling mud is a critical aspect of the drilling process. A well-designed drilling mud should not only provide efficient mud hydraulics but also fulfill three important functions: enhancing mud rheology, inhibiting hydrate formation in deepwater drilling, and suppressing shale swelling when drilling through shale formations. Achieving these functions often requires the use of various additives, but these additives are often expensive, non-biodegradable, and have significant environmental impacts. To address these concerns, researchers have explored the potential applications of ionic liquids and deep eutectic solvents in drilling mud design, which have shown promising results. However, an even more environmentally friendly alternative has emerged in the form of natural deep eutectic solvents (NADES). This research focuses on an in-house-prepared NADES based on calcium chloride and glycerine, with a ratio of 1:4, prepared at 60 °C, and utilizes it as a drilling mud additive following the API 13 B-1 standards and checks its candidacy as a rheology modifier, hydrates, and shale inhibitor. The findings of the study demonstrate that the NADES-based mud significantly improves the overall yield point to plastic viscosity ratio (YP/PV) of the mud, provides good gel strength, and inhibits hydrate formation by up to 80%. Additionally, it has shown an impressive 62.8% inhibition of shale swelling while allowing for 84.1% improved shale recovery. Moreover, the NADES-based mud exhibits a 28% and 25% reduction in mud filtrate and mud cake thickness, respectively, which is further supported by the results of XRD, zeta potential, and surface tension. Based on these positive outcomes, the calcium chloride–glycerine NADES-based mud is recommended as a versatile drilling mud additive suitable for various industrial applications. Furthermore, it presents a more environmentally friendly option compared to traditional additives, addressing concerns about cost, biodegradability, and environmental impact in the drilling process for an ultimate global impact.
KW - NADES
KW - Shale swelling
KW - Drilling fluid
KW - Mud rheology
KW - Hydrate inhibition
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623918
DO - https://doi.org/10.3390/en16145533
SN - 1996-1073
VL - 16
IS - 14
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-62391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, André
A1 - Hasenbein, Ines
A1 - Hortschansky, Peter
A1 - Schmuck, Klaus D.
A1 - Maenz, Stefan
A1 - Illerhaus, Bernhard
A1 - Kuehmstedt, Peter
A1 - Ramm, Roland
A1 - Huber, René
A1 - Kunisch, Elke
A1 - Horbert, Victoria
A1 - Gunnella, Francesca
A1 - Roth, Andreas
A1 - Schubert, Harald
A1 - Kinne, Raimund W.
T1 - BMP-2 (and partially GDF-5) coating significantly accelerates and augments bone formation close to hydroxyapatite/tricalcium-phosphate/brushite implant cylinders for tibial bone defects in senile, osteopenic sheep
N2 - Bilateral defects (diameter 8 mm) in the medial tibial head of senile, osteopenic female sheep (n = 48; 9.63 ± 0.10 years; mean ± SEM) were treated with hydroxyapatite (HA)/beta-tricalcium phosphate (β-TCP)/dicalcium phosphate dihydrate (DCPD; brushite) cylinders coated with BMP-2 (25 or 250 micrograms) or growth differentiation factor (GDF)-5 (125 or 1250 micrograms; left side); cylinders without BMP served as controls (right side). Three, 6, and 9 months post-operation (n = 6 each group), bone structure and formation were analyzed in vivo by X-ray and ex vivo by osteodensitometry, histomorphometry, and micro-computed tomography (micro-CT) at 3 and 9 months. Semi-quantitative X-ray evaluation showed significantly increasing bone densities around all implant cylinders over time. High-dose BMP-2-coated cylinders (3 and 9 months) and low-dose GDF-5-coated cylinders (3 and 6 months) demonstrated significantly higher densities than controls (dose-dependent for BMP-2 at 3 months). This was confirmed by osteodensitometry at 9 months for high-dose BMP-2-coated cylinders (and selected GDF-5 groups), and was again dose-dependent for BMP-2. Osteoinduction by BMP-2 was most pronounced in the adjacent bone marrow (dynamic histomorphometry/micro-CT). BMP-2 (and partially GDF-5) significantly increased the bone formation in the vicinity of HA/TCP/DCPD cylinders used to fill tibial bone defects in senile osteopenic sheep and may be suitable for surgical therapy of critical size, non-load-bearing bone defects in cases of failed tibial head fracture or defect healing.
KW - Bone morphogenetic protein (BMP)
KW - Growth differentiation factor (GDF)
KW - Bone replacement material
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623923
DO - https://doi.org/10.1007/s10856-023-06734-2
SN - 1573-4838
VL - 34
IS - 7
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
CY - Dordrecht
AN - OPUS4-62392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Westwood, Steven
A1 - Lippa, Katrice
A1 - Shimuzu, Yoshitaka
A1 - Lalerle, Beatrice
A1 - Saito, Takeshi
A1 - Duewer, David
A1 - Dai, Xinhua
A1 - Davies, Stephen
A1 - Ricci, Marina
A1 - Baldan, Annarita
A1 - Lang, Brian
A1 - Sarge, Stefan
A1 - Wang, Haifeng
A1 - Pratt, Ken
A1 - Josephs, Ralf
A1 - Mariassy, Mikael
A1 - Pfeifer, Dietmar
A1 - Warren, John
A1 - Bremser, Wolfram
A1 - Ellison, Stephen
A1 - Toman, Blaza
A1 - Nelson, Michael
A1 - Huang, Ting
A1 - Fajgelj, Ales
A1 - Gören, Ahmet
A1 - Mackay, Lindsey
A1 - Wielgosz, Robert
T1 - Methods for the SI-traceable value assignment of the purity of organic compounds (IUPAC Technical Report)
N2 - The “purity” of an organic compound typically refers, in practice, to an assignment of the mass fraction content of the primary organic component present in the material. The “purity” value of an organic primary calibrator material is the ultimate source of metrological traceability of any quantitative measurement of the content of that compound in a given matrix. The primary calibrator may consist of a Certified Reference Material (CRM) whose purity has been assigned by the CRM producer or a laboratory may choose to value-assign a material to the extent necessary for their intended application by using appropriately valid methods. This report provides an overview of the approach, performance and applicability of the principal methods used to determine organic purity including mass balance, quantitative NMR, thermal methods and direct-assay techniques. A statistical section reviews best practice for combination of data, value assignment as the upper limit values corresponding to 100 % purity are approached and how to report and propagate the standard uncertainty associated with the assigned values.
KW - Calibration hierarchy
KW - Certified reference materials
KW - Mass balance
KW - Measurement uncertainty
KW - Organic purity
KW - Primary calibrators
KW - Primary reference materials
KW - qNMR
KW - Related-structure impurities
KW - Thermal analysis
KW - Titrimetry
KW - Traceability
KW - Uncertainty propagation
KW - Volatile organic compounds
KW - Water content
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627932
DO - https://doi.org/10.1515/pac-2020-0804
SN - 0033-4545
SN - 1365-3075
VL - 95
IS - 1
SP - 1
EP - 77
PB - de Gruyter
CY - Berlin
AN - OPUS4-62793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Mike
A1 - Couzinié, Jean-Philippe
A1 - Shalabi, Amin
A1 - Ibrahimkhel, Farhad
A1 - Ferrari, Alberto
A1 - Körmann, Fritz
A1 - Laplanche, Guillaume
T1 - Effect of stacking fault energy on the thickness and density of annealing twins in recrystallized FCC medium and high-entropy alloys
N2 - This work aims to predict the microstructure of recrystallized medium and high-entropy alloys (MEAs and HEAs) with a face-centered cubic structure, in particular the density of annealing twins and their thickness. Eight MEAs and five HEAs from the Cr-Mn-Fe-Co-Ni system are considered, which have been cast, homogenized, cold-worked and recrystallized to obtain different grain sizes. This work thus provides a database that could be used for data mining to take twin boundary engineering for alloy development to the next level. Since the stacking fault energy is known to strongly affect recrystallized microstructures, the latter was determined at 293 K using the weak beam dark-field technique and compared with ab initio simulations, which additionally allowed to calculate its temperature dependence. Finally, we show that all these data can be rationalized based on theories and empirical relationships that were proposed for pure metals and binary Cu-based alloys.
KW - CoCrFeMnNi HEAs and MEAs
KW - Recrystallization
KW - Transmission electron microscopy (TEM)
KW - Electron backscatter diffraction
KW - Grain boundary engineering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629346
DO - https://doi.org/10.1016/j.scriptamat.2023.115844
SN - 1359-6462
VL - 240
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sparber‐Sauer, Monika
A1 - Ferrari, Andrea
A1 - Kosztyla, Daniel
A1 - Ladenstein, Ruth
A1 - Cecchetto, Giovanni
A1 - Kazanowska, Bernarda
A1 - Scarzello, Giovanni
A1 - Ljungman, Gustaf
A1 - Milano, Giuseppe Maria
A1 - Niggli, Felix
A1 - Alaggio, Rita
A1 - Vokuhl, Christian
A1 - Casanova, Michela
A1 - Klingebiel, Thomas
A1 - Zin, Angelica
A1 - Koscielniak, Ewa
A1 - Bisogno, Gianni
T1 - Long‐term results from the multicentric European randomized phase 3 trial CWS/RMS‐96 for localized high‐risk soft tissue sarcoma in children, adolescents, and young adults
N2 - Background: CWS/RMS‐96 was an international multicenter trial with randomization between two therapy arms of the standard four‐drug therapy (vincristine, ifosfamide, adriamycin, dactinomycin [VAIA]) versus an intensified six‐drug regimen (carboplatin, epirubicin, vincristine, dactinomycin, ifosfamide, and etoposide [CEVAIE]) for high‐risk rhabdomyosarcoma (RMS), extraskeletal Ewing sarcoma (EES), and undifferentiated sarcoma (UDS) in children, adolescents, and young adults aiming to improve their survival. Intensified chemotherapy with CEVAIE did not improve outcome.
Methods: Patients younger than 21 years with a previously untreated localized HR‐RMS, EES, and UDS were enrolled from Cooperative Weichteilsarkom Studiengruppe (CWS) centers in Germany, Austria, Poland, Switzerland, and from Italian Soft Tissue Sarcoma Committee (STSC) centers. Randomization (1:1) to receive either 9 × 21 days cycles of VAIA or CEVAIE was performed separately in CWS and STSC. Hyperfractionated accelerated radiotherapy (32–44.8 Gy) was added at week 9–12 according to histology and response to chemotherapy. A secondary microscopically complete nonmutilating resection was performed if possible. Primary endpoints were response to chemotherapy, event‐free (EFS) and overall survival (OS).
Results: Five hundred fifty‐seven patients (HR‐RMS:n = 416, EES and UDS:n = 141) underwent randomization: VAIA (n = 273) or CEVAIE (n = 284). Radiotherapy was given to 70% of patients in both groups. A secondary resection was performed in 47% and 48% patients, respectively. The 5‐year EFS and OS for the VAIA and CEVAIE treatment arms were 59.8% and 60.8% (p = .89), and 74.2% and 68.3% (p = .16), respectively. No differences in response, toxicity, or second malignancies emerged in the two groups.
Conclusion: The use of an intensified regimen failed to show a significant improvement in tumor response and outcome of patients with localized HR‐RMS, EES, and UDS.
KW - CEVAIE
KW - CWS-96
KW - High-risk soft tissue sarcoma
KW - Randomization
KW - Rhabdomyosarcoma
KW - RMS-96
KW - VAIA
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629373
DO - https://doi.org/10.1002/pbc.29691
SN - 1545-5017
VL - 69
IS - 9
SP - 1
EP - 11
PB - Wiley
CY - New York, NY
AN - OPUS4-62937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Paul, Nathalie
A1 - Kister, Alexander
A1 - Schnellhardt, Thorben
A1 - Fetz, Maximilian
A1 - Hecker, Dirk
A1 - Wirtz, Tim
ED - Meo, Rosa
ED - Silvestri, Fabrizio
T1 - Reinforcement Learning for Segmented Manufacturing
N2 - The manufacturing of large components is, in comparison to small components, cost intensive. This is due to the sheer size of the components and the limited scalability in number of produced items. To take advantage of the effects of small component production we segment the large components into smaller parts and schedule the production of these parts on regular-sized machine tools. We propose to apply and adapt recent developments in reinforcement learning in combination with heuristics to efficiently solve the resulting segmentation and assignment problem. In particular, we solve the assignment problem up to a factor of 8 faster and only a few percentages less accurate than a classic solver from operations research.
T2 - European Conference on Machine Learning and Principles and Practice of Knowledge Discovery in Databases 2023
CY - Turin, Italy
DA - 18.09.2023
KW - Reinforcement Learning
KW - Assignment Problem
KW - Large component manufacturing
PY - 2025
DO - https://doi.org/10.1007/978-3-031-74640-6_38
VL - 1
IS - 1
SP - 470
EP - 485
PB - Springer Cham
AN - OPUS4-63031
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reigl, Selina
A1 - Van Driessche, Alexander
A1 - Stawski, Tomasz
A1 - Koltzenburg, Sebastian
A1 - Kunz, Werner
A1 - Kellermeier, Matthias
T1 - Sustainable Pathways for the Synthesis of Calcium Sulfate Hemihydrate
N2 - Calcium sulfate, and especially its hemihydrate form (bassanite), is crucial in the construction industry, primarily used as a hydraulic binder in cements, mortars, and wallboards. Because of the rapid transformation of bassanite into thermodynamically stable gypsum (calcium sulfate dihydrate) upon contact with water, natural deposits are scarce, rendering it one of the most extensively produced inorganic materials worldwide. Currently, bassanite is derived from mined or waste gypsum through a thermal dehydration process, which is energy-intensive and costly. As sustainability has become a key target for industrial processes and products, a series of studies aiming to increase the energy efficiency and reduce the carbon footprint of bassanite production was published recently. Two primary approaches are pursued: conversion of gypsum and direct precipitation of bassanite from solution. In both cases, organic solvents, (specific) additives and/or elevated temperatures have been used to control the activity/availability of water in the reaction medium and thus direct phase selection towards bassanite. This review offers a comprehensive overview of alternative bassanite production methods, critically examining their benefits, potential downsides, and overall impact on
the sustainability of industrial-scale use.
KW - Calcium sulfate
KW - Gypsum
KW - Bassanite
KW - Recycling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630657
DO - https://doi.org/10.1002/anie.202415161
SN - 1521-3773
SP - 1
EP - 20
PB - Wiley VHC-Verlag
AN - OPUS4-63065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Alexander
A1 - Dingel, Kristina
A1 - Kottke, Daniel
A1 - Degener, Sebastian
A1 - Meier, David
A1 - Sick, Bernhard
A1 - Niendorf, Thomas
T1 - Data selection strategies for minimizing measurement time in materials characterization
N2 - Every new material needs to be assessed and qualified for an envisaged application. A steadily increasing number of new alloys, designed to address challenges in terms of reliability and sustainability, poses significant demands on well-known analysis methods in terms of their efficiency, e.g., in X-ray diffraction analysis. Particularly in laboratory measurements, where the intensities in diffraction experiments tend to be low, a possibility to adapt the exposure time to the prevailing boundary conditions, i.e., the investigated microstructure, is seen to be a very effective approach. The counting time is decisive for, e.g., complex texture, phase, and residual stress measurements. Traditionally, more measurement points and, thus, longer data collection times lead to more accurate information. Here, too short counting times result in poor signal-to-background ratios and dominant signal noise, respectively, rendering subsequent evaluation more difficult or even impossible. Then, it is necessary to repeat experiments with adjusted, usually significantly longer counting time. To prevent redundant measurements, it is state-of-the-art to always consider the entire measurement range, regardless of whether the investigated points are relevant and contribute to the subsequent materials characterization, respectively. Obviously, this kind of approach is extremely time-consuming and, eventually, not efficient. The present study highlights that specific selection strategies, taking into account the prevailing microstructure of the alloy in focus, can decrease counting times in X-ray energy dispersive diffraction experiments without any detrimental effect on data quality for the subsequent analysis. All relevant data, including the code, are carefully assessed and will be the basis for a widely adapted strategy enabling efficient measurements not only in lab environments but also in large-scale facilities.
KW - Materials characterization
KW - Machine learning
KW - X-ray diffraction
KW - Measurement optimization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630831
DO - https://doi.org/10.1038/s41598-025-96221-1
SN - 2045-2322
VL - 15
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-63083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sridaran Venkat, Ramanan
A1 - Stamm, Michael
A1 - Wittmann, Jost
A1 - Lauterbach, Helge
A1 - Bleier, Michael
T1 - Harnessing the power of thermal imagery and visual inspection- a mean for reliable damage detection of wind turbine rotor blades
N2 - Generation of green electricity as part of the energy transition is leading to a growing market in the wind energy sector all over the world. Maintenance and inspection are key-factor for the reliable, safe and efficient operation of wind turbines. Regular maintenance of rotor blades focuses on damage such as erosion on the leading edge of the profile, delamination and thermal cracks due to lightning strikes. To date, visual inspection by technicians (climbers) has been the state of the art. Recently, drone-based inspections using visual cameras have become more common, enabling fast, reliable and cost-effective inspections. However, no internal damage to the rotor blades are detectable during such an inspection. This deficiency is often compensated by thermography, a recognized method for detecting damages beneath the surface of an object. Thermography has been promoted and continuously developed at BAM for years. In the first part of this paper, the authors present the concept for a drone-based multisensory system that combines a thermal camera, a high-resolution visual camera and a 3D Laser scanner.The system provides a comprehensive view of the rotor blade samples internal and external conditions. In the second part of the paper, we present a lab-based demonstrator comprising an infrared camera and an RGB camera. We elaborate on the process for fusing the images comprising the calibration, image preprocessing and image registration.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Wind rotor blade inspection
KW - Thermography
KW - Data fusion
KW - Drone inspection
KW - Multi-sensors
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625107
DO - https://doi.org/10.58286/29868
SN - 1435-4934
VL - 29
SP - 1
EP - 8
AN - OPUS4-62510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zia, Ghezal Ahmad Jan
A1 - Valdestilhas, Andre
A1 - Moreno Torres, Benjami
A1 - Kruschwitz, Sabine
T1 - Leveraging large language models for automated knowledge graphs generation in non-destructive testing
N2 - This paper presents an innovative approach for the automatic generation of Knowledge Graphs (KGs) from heterogeneous scientific articles in the domain of Non-Destructive Testing (NDT) applied to building materials.
Our methodology leverages large language models (LLMs) to extract and semantically relate concepts from diverse sources. We developed material-specific agents for concrete, wood, steel, and bricks, each equipped with a curated glossary of terms to ensure domain accuracy. These agents process PDF documents, extracting relevant information on deterioration mechanisms, physical changes, and applicable NDT methods. The extracted data is then normalized, validated, and structured into a Neo4j graph database, forming a comprehensive KG. Our results demonstrate the system’s ability to automatically discover and represent intricate relationships between materials, deterioration mechanisms, physical changes, and NDT techniques. The generated KG successfully captures complex interactions, such as the applicability of specific NDT methods to various materials under different deterioration conditions. This work not only highlights the potential of KGs in enhancing knowledge discovery and representation in NDT research but also provides a scalable framework for extending this approach to other scientific domains.
T2 - SeMatS 2024 - The 1st International Workshop on Semantic Materials Science
CY - Amsterdam, The Netherlands
DA - 17.09.2024
KW - Materials science and engineering
KW - Large language model
KW - Linked open data
KW - Data interoperability
KW - RDF
KW - Semantic web
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624597
DO - https://doi.org/10.5281/zenodo.13834164
SN - 1613-0073
N1 - Serientitel: CEUR workshop proceedings – Series title: CEUR workshop proceedings
VL - 3760
SP - 101
EP - 110
PB - RWTH Aachen
CY - Aachen
AN - OPUS4-62459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liao, Chun-Man
ED - Zhang, Jian
T1 - Modal and Wave Propagation Analysis of Vibration Tests on a Laboratory Building Model Before and After Damage
N2 - Weakened structural stiffness is often a consequence of building damage, particularly after severe events such as earthquakes, where compromised structural performance can pose significant risks. To prevent immediate structural failure, an early warning system is essential, which requires inspection of local components. This research aims to achieve that by exploring the wave propagation analysis method, specifically seismic interferometry. Previous studies have applied this method to building structures, treating them as homogeneous layers of grouped floors. By analyzing the wave travel time along the height of these layers, the fundamental period of the building was estimated. However, this approach did not account for local damage or the variability of structural components, similar to the limitations of vibration‐based damage detection methods, which mainly identify global changes. Thus, the goal of this paper is to improve structural health monitoring by examining the sensitivity of wave screening, bridging the gap between nondestructive testing and vibration‐based damage detection. A half‐scale, seven‐story building model, characterized by vertical stiffness irregularity and transverse plan asymmetry, was tested in a laboratory setting. Two vertical sensor arrays were placed near corner columns of different sizes, representing both strong and weak structural areas. These arrays recorded floor accelerations in three directions. The study confirmed the effectiveness of wave propagation analysis for detecting damage along the sensor arrays before and after the earthquake. A transmissibility damage indicator was used to correlate changes in wave velocity, providing a quantitative assessment of damage levels along the wave propagation path.
KW - Damage location
KW - Laboratory test
KW - Soft story
KW - Stifness irregular structure
KW - Structural health monitoring
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624931
DO - https://doi.org/10.1155/stc/3453150
SN - 1545-2263
VL - 2025
IS - 1
SP - 1
EP - 17
PB - John Wiley & Sons Ltd.
AN - OPUS4-62493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nagel, Thomas
A1 - Rühaak, Wolfram
A1 - Amann, Florian
A1 - Bracke, Guido
A1 - Buske, Stefan
A1 - Kowalski, Julia
A1 - Reiche, Sönke
A1 - Schäfer, Thorsten
A1 - Scheytt, Traugott
A1 - Stumpf, Thorsten
A1 - Völzke, Holger
A1 - Wellmann, Florian
A1 - Kolditz, Olaf
T1 - Deep geological disposal - Editorial to the topical collection
N2 - The subsurface geological environment, historically a key source of fossil and mineral resources, has seen a significant broadening of its potential applications in recent years, with increasing emphasis on its use for energy production and storage.
A critical factor in utilizing subsurface space is ensuring the sustainability of management practices, with particular attention to the potential environmental impacts that may result.
The current Topical Collection on Deep Geological Disposal places greater emphasis on the geotechnical aspects of geological disposal, with a particular focus on the safe isolation of hazardous materials, including radioactive waste. The Topical Collection on Deep Geological Disposal covers both experimental (laboratory and in-situ) and theoretical studies of various geotechnical applications, such as geological disposal of radioactive or other materials, e.g. coal-based solid waste, carbon dioxide sequestration in fractured reservoirs, and brine solutions, but also aspects of uranium mining.
The articles in the Topical Collections are arranged under
the following headings:
– Fundamental studies
– Experimental studies
– Numerical studies
KW - Disposal
KW - Radioactive Waste
KW - Geology
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624955
DO - https://doi.org/10.1007/s12665-024-12075-2
SN - 1866-6299
VL - 84
IS - 3
SP - 1
EP - 6
PB - Springer Nature
AN - OPUS4-62495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Titscher, Thomas
A1 - van Dijk, T.
A1 - Kadoke, Daniel
A1 - Robens-Radermacher, Annika
A1 - Herrmann, Ralf
A1 - Unger, Jörg F.
T1 - Bayesian model calibration and damage detection for a digital twin of a bridge demonstrator
N2 - Using digital twins for decision making is a very promising concept which combines simulation models with corresponding experimental sensor data in order to support maintenance decisions or to investigate the reliability. The quality of the prognosis strongly depends on both the data quality and the quality of the digital twin. The latter comprises both the modeling assumptions as well as the correct parameters of these models. This article discusses the challenges when applying this concept to realmeasurement data for a demonstrator bridge in the lab, including the data management, the iterative development of the simulation model as well as the identification/updating procedure using Bayesian inference with a potentially large number of parameters. The investigated scenarios include both the iterative identification of the structural model parameters as well as scenarios related to a damage identification. In addition, the article aims at providing all models and data in a reproducibleway such that other researcher can use this setup to validate their methodologies.
KW - Damage detection
KW - Finite element analysis
KW - Load identification
KW - Model updating
KW - Estimation
KW - System identification
KW - Variational Bayesian statistics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574496
DO - https://doi.org/10.1002/eng2.12669
SN - 2577-8196
SP - 1
EP - 27
PB - Wiley
CY - Hoboken, NJ
AN - OPUS4-57449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diercks, Philipp
A1 - Veroy, K.
A1 - Robens-Radermacher, Annika
A1 - Unger, Jörg F.
T1 - Multiscale modeling of linear elastic heterogeneous structures via localized model order reduction
N2 - In this paper, a methodology for fine scale modeling of large scale linear elastic structures is proposed, which combines the variational multiscale method, domain decomposition and model order reduction. The influence of the fine scale on the coarse scale is modelled by the use of an additive split of the displacement field, addressing applications without a clear scale separation. Local reduced spaces are constructed by solving an oversampling problem with random boundary conditions. Herein, we inform the boundary conditions by a global reduced problem and compare our approach using physically meaningful correlated samples with existing approaches using uncorrelated samples. The local spaces are designed such that the local contribution of each subdomain can be coupled in a conforming way, which also preserves the sparsity pattern of standard finite element assembly procedures. Several numerical experiments show the accuracy and efficiency of the method, as well as its potential to reduce the size of the local spaces and the number of training samples compared to the uncorrelated sampling.
KW - Multiscale methods
KW - Variational multiscale method
KW - Localized model order reduction
KW - Domain decomposition methods
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580671
DO - https://doi.org/10.1002/nme.7326
SN - 0029-5981
SP - 1
EP - 23
PB - Wiley online library
AN - OPUS4-58067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klewe, Tim
A1 - Strangfeld, Christoph
A1 - Kruschwitz, Sabine
T1 - Review of moisture measurements in civil engineering with ground penetrating radar – Applied methods and signal features
N2 - When applying Ground Penetrating Radar (GPR) to assess the moisture content of building materials, different medium properties, dimensions, interfaces and other unknown influences may require specific strategies to achieve useful results. Hence, we present an overview of the various approaches to carry out moisture measurements with GPR in civil engineering (CE). We especially focus on the applied Signal features such as time, amplitude and frequency features and discuss their limitations. Since the majority of publications rely on one single feature when applying moisture measurements, we also hope to encourage the consideration of approaches that combine different signal features for further developments.
KW - Ground Penetrating Radar
KW - Moisture
KW - Civil engineering
KW - Signal features
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520684
DO - https://doi.org/10.1016/j.conbuildmat.2021.122250
VL - 278
SP - 122250
PB - Elsevier Ltd.
AN - OPUS4-52068
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Robens-Radermacher, Annika
A1 - Held, Felix
A1 - Coelho Lima, Isabela
A1 - Titscher, Thomas
A1 - Unger, Jörg F.
T1 - Efficient identification of random fields coupling Bayesian inference and PGD reduced order model for damage localization
N2 - One of the main challenges regarding our civil infrastructure is the efficient operation over their complete design lifetime while complying with standards and safety regulations. Thus, costs for maintenance or replacements must be optimized while still ensuring specified safety levels. This requires an accurate estimate of the current state as well as a prognosis for the remaining useful life. Currently, this is often done by regular manual or visual inspections within constant intervals. However, the critical sections are often not directly accessible or impossible to be instrumented at all. Model‐based approaches can be used where a digital twin of the structure is set up. For these approaches, a key challenge is the calibration and validation of the numerical model based on uncertain measurement data. The aim of this contribution is to increase the efficiency of model updating by using the advantage of model reduction (Proper Generalized Decomposition, PGD) and applying the derived method for efficient model identification of a random stiffness field of a real bridge.”
KW - Model reduction
KW - Model updating
KW - Proper generalized decomposition
KW - Random field
KW - Variational Bayesian Inference
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521275
DO - https://doi.org/10.1002/pamm.202000063
VL - 20
IS - 1
SP - e202000063
PB - Wiley Online Libary
AN - OPUS4-52127
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Ghnatios, C.
A1 - Robens-Radermacher, Annika
T1 - PGD in thermal transient problems with a moving heat source: A sensitivity study on factors affecting accuracy and efficiency
N2 - Thermal transient problems, essential for modeling applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting their applications, for example for model parameter estimation or online process control. Model order reduction, a solution to preserve the accuracy while reducing the computation time, is explored. This article addresses challenges in developing reduced order models using the proper generalized decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model’s performance and emphasize the importance of their consideration when implementing such models. For thermal example, it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model.
KW - Additive manufacturing
KW - Mapping for unseparable load
KW - Model order reduction (MOR)
KW - Thermal transient problem
KW - Sensitivity analysis
KW - Proper generalized decomposition (PGD)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598001
DO - https://doi.org/10.1002/eng2.12887
VL - 6
IS - 11
SP - 1
EP - 22
PB - John Wiley & Sons Ltd.
CY - Berlin
AN - OPUS4-59800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Klewe, Tim
T1 - Comparison of the Calcium Carbide Method and Darr Drying to Quantify the Amount of Chemically Bound Water in Early Age Concrete
N2 - Hydration is the exothermic reaction between anhydrous cement and water, which forms the solid cement matrix of concrete. Being able to evaluate the hydration is of high interest for the use of both conventional and more climate-friendly building materials. The experimental monitoring is based on temperature or moisture measurements. The first needs adiabatic conditions, which can only be achieved in laboratory. The latter is often measured comparing the weight of the material sample before and after oven drying, which is time-consuming. This study investigates the moisture content of two cement-based and two calcium sulphate based mixtures for the first 90 days by using the calcium carbide method and oven drying at 40 °C and 105 °C (Darr method). Thereby, the amount of chemically bound water is determined to derive the degree of hydration. The calcium carbide measurements highly coincide with oven drying at 40 °C. The calcium carbide method is therefore evaluated as a suitable alternative to the time-consuming Darr drying. The prompt results are seen as a remarkable advantage and can be obtained easily in laboratory as well as in the field.
KW - Concrete
KW - Hydration
KW - Material moisture
KW - Calcium carbide method
KW - Bound water
KW - Darr method
KW - Oven drying
KW - Chemisorption
KW - Physisorption
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564519
DO - https://doi.org/10.3390/ma15238422
VL - 15
IS - 23
SP - 1
EP - 16
PB - MDPI
AN - OPUS4-56451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strangfeld, Christoph
A1 - Stolpe, Heiko
A1 - Wiehle, Philipp
T1 - Moisture diffusion affected by the Knudsen effect in temporal changing pore networks
N2 - Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores (< 1 µm), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption.
In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany.
The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. This effect becomes most prominent in the meso-pore range and might alter the effective diffusion coefficient by more than 100 %.
T2 - 4th International Congress on Materials & Structural Stability
CY - Rabat, Morocco
DA - 08.03.2023
KW - Earth masonry
KW - Material moisture
KW - Molecular diffusion
KW - Chemisoprtion
KW - Knudsen effect
KW - Physisorption
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571391
SP - 1
EP - 8
PB - RILEM
CY - Champs-sur-Marne
AN - OPUS4-57139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Johann, Sergej
A1 - Strangfeld, Christoph
A1 - Zimmek, David
A1 - Bartholmai, Matthias
T1 - Smart electronic helper for long-term monitoring of bridges and building structures
N2 - Increasing traffic volume on the one hand and ageing infrastructure on the other hand have created many new challenges for maintenance and structural health monitoring of roads and bridges. In the past, many bridges and road structures have been neglected, often resulting in traffic congestion, road closure, and increased repair costs.
This research is concerned with the development of a system to improve the challenge of maintenance and early detection of damage, particularly moisture penetration and corrosion of steel reinforced concrete components. The objective is to develop a method that will also work after 30 years and longer. Many new IoT solutions are equipped with internal energy storage elements (accumulators or batteries) which are inappropriate here, since most relevant signs of concrete degradation occur after decades, where the functioning of such elements are more than questionable. The presented technology approach uses radio-frequency identification (RFID) and enables connectivity to sensors. It offers the advantage of an passive, completely independent energy supply without any energy storage components.
Since the system should be permanently embedded in concrete, it is crucial to develop a long-term stable device which is adapted to the environmental influences of the structure, e.g., long-term resistance in very alkaline environment of pH 13. In numerous experiments, the robustness of the system was tested and evaluated. Various tests with encapsulations to protect the electronics were performed, and for long-term validation different concrete specimens were instrumented with RFID-sensor-systems. Their operating time is now around two years and investigations for signs of fatigue and damage to the encapsulation and the electronics are ongoing.
T2 - SMAR 2019
CY - Potsdam, Germany
DA - 27.08.2019
KW - Sensors
KW - Passive RFID
KW - Smart structures
KW - SHT
KW - Long term monitoring
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501931
UR - https://www.ndt.net/?id=25011
SN - 1435-4934
VL - 25
IS - 1
SP - 1
EP - 6
PB - NDT.net
CY - Kirchwald
AN - OPUS4-50193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diercks, Philipp
A1 - Gläser, Dennis
A1 - Lünsdorf, Ontje
A1 - Selzer, Michael
A1 - Flemisch, Bernd
A1 - Unger, Jörg F.
T1 - Evaluation of tools for describing, reproducing and reusing scientific workflows
N2 - In the field of computational science and engineering, workflows often entail the application of various software, for instance, for simulation or pre- and postprocessing.
Typically, these components have to be combined in arbitrarily complex workflows to address a specific research question. In order for peer researchers to understand, reproduce and (re)use the findings of a scientific publication, several challenges have to be addressed. For instance, the employed workflow has to be automated and information on all used software must be available for a reproduction of the results. Moreover, the results must be traceable and the workflow documented and readable to allow for external verification and greater trust.
In this paper, existing workflow management systems (WfMSs) are discussed regarding their suitability for describing, reproducing and reusing scientific workflows. To this end, a set of general requirements for WfMSs were deduced from user stories that we deem relevant in the domain of computational science and engineering. On the basis of an exemplary workflow implementation, publicly hosted at GitHub (https://github.com/BAMresearch/NFDI4IngScientificWorkflowRequirements), a selection of different WfMSs is compared with respect to these requirements, to support fellow scientists in identifying the WfMSs that best suit their requirements.
KW - FAIR
KW - Reproducibility
KW - Scientific workflows
KW - Tool comparison
KW - Workflow management
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584832
DO - https://doi.org/10.48694/inggrid.3726
VL - 1
IS - 1
SP - 1
EP - 27
AN - OPUS4-58483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Stolpe, Heiko
A1 - Wiehle, Philipp
T1 - Moisture diffusion affected by the Knudsen effect in temporal changing pore networks
N2 - Almost all building materials in civil engineering have an open porosity and interact with or are affected by the environmental conditions. Structures might suffer from effects such as moisture adsorption, carbonation, corrosion, penetration of salt ions and chemical substances, etc. In the hygroscopic range, these processes are mostly driven by diffusion. Due to the confinement of small pores (less than1 µm), the Knudsen effect reduces the molecular diffusion. This reduction can become more significant in case of temporal changing pore systems because of physisorption of water vapor, carbonation, or chemisorption.
In this study, unstabilised earth blocks and earth masonry are investigated. In a first step, the pore size distribution of the blocks is measured and sorption isotherms are recorded in experiments. Besides the ordinary physisorption, the involved clay minerals undergo swelling or shrinking due to chemisorption. The following two effects must be considered: first, the reduction of the available pore space by the adsorbed water layer. For this, the Hillerborg sorption theory is used, which is a combination of the well-known Brunauer-Emmett-Teller sorption theory and the Kelvin equation. This allows the computation of adsorbed water layers even in curved pore geometries. Second, the variation of the initial pore size distribution due to chemisorption needs to be modelled. Based on these two models, the effective diffusion coefficient can be predicted. For validation, arrays of relative humidity sensors were embedded into a free-standing earth masonry wall. This monitoring was carried out over more than a year to have a broad variety of environmental conditions and was located in Berlin, Germany.
The prediction of the effective diffusion coefficient can also be transferred to other processes and allows the investigation of materials having temporarily changing pore systems. Examples are the carbonation of cementitious materials, alkali silica reaction, calcium leaching of long-lasting structures, etc. These effects are prominent in the meso-pore range and might significantly alter the effective diffusion coefficient.
KW - Earth material
KW - Material moisture
KW - Physisoprtion
KW - Chemisorption
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583811
DO - https://doi.org/10.1016/j.matpr.2023.09.034
SN - 2214-7853
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-58381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schnell, A.
A1 - Rübner, Katrin
A1 - Seher, Julia
A1 - Müller, A.
A1 - Liebezeit, S.
A1 - Fenner, J.
A1 - Martin, F.
A1 - Pniok, N.
T1 - REALight ‐ Leichtgranulate und REA‐Gips aus feinkörnigen sulfatbelasteten Bau‐ und Abbruchabfällen
N2 - Ziel des Projekts REALight ist die Entwicklung einer Referenzanlage zur Herstellung von Leichtgranulaten (leichte Gesteinskörnungen) aus Bau‐ und Abbruchabfällen und zur Gipsrückgewinnung. Als Rohstoffe werden bisher ungenutzte oder auf niedrigem Niveau eingesetzte Bau‐ und Abbruchabfälle und industrielle Nebenprodukte verwendet. Als Produkte werden leichte Gesteinskörnungen hergestellt. Die Sulfatabtrennung durch eine thermische Zersetzung bildet die Grundlage für die zusätzliche Gewinnung von Rauchgasentschwefelungs‐Gips (REA‐Gips). Das Projekt wird im Rahmen der Fördermaßnahme „Ressourceneffiziente Kreislaufwirtschaft – Bauen und Mineralische Stoffkreisläufe (ReMin)” gefördert. ReMin ist eine Maßnahme zur Umsetzung des BMBF‐Forschungskonzepts „Ressourceneffiziente Kreislaufwirtschaft” als Teil der BMBF Strategie „Forschung für nachhaltige Entwicklung – FONA”. Ziel der Förderung ist es, den Ausbau der Kreislaufwirtschaft voranzutreiben. Im Mittelpunkt steht dabei die Bauwirtschaft mit ihrer hohen Nachfrage nach Rohstoffen und gleichzeitig großen Mengen an anfallenden mineralischen Abfällen. Am Projekt REALight sind 12 Partner aus verschiedenen Bereichen der Baustoffherstellung und ‐anwendung, Abfallaufbereitung, Verfahrenstechnik sowie Forschung und Entwicklung beteiligt.
T2 - 21. Internationale Baustofftagung (ibausil)
CY - Weimar, Germany
DA - 13.09.2023
KW - Baustoffrecycling
KW - Leichtgranulate
KW - Gips
KW - Leichte Gesteinskörnungen
KW - Drehrohrofen
KW - Recycling
KW - Mauerwerkbruch
KW - Infraleichtbeton
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591708
DO - https://doi.org/10.1002/cepa.2840
SN - 2509-7075
VL - 6
IS - 6
SP - 530
EP - 536
PB - Ernst & Sohn
CY - Berlin
AN - OPUS4-59170
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Seher, Julia
A1 - Rübner, Katrin
A1 - Schnell, A.
A1 - Hahn, A.
A1 - Bruch, I.
A1 - Alewell, U.
A1 - Vöge, M.
A1 - Shafiei, K.
A1 - Schumann, G.
ED - Pfaff, G.
ED - Mertzsch, N.
ED - Jeremias, E.-P.
T1 - Hydrothermalgranulate – Eine Verwertungsmöglichkeit für Mauerwerkbruch
N2 - Im Jahr 2020 fielen in Deutschland rund 220 Millionen Tonnen mineralische Bau- und Abbruchabfälle an, die als Sekundärrohstoffquelle genutzt werden können. Trotz hoher Recyclingquoten wird ein Teil der mineralischen Bau- und Abbruchabfälle immer noch deponiert oder in Anwendungen mit geringen Qualitätsanforderungen eingesetzt, da ein effektives Recycling dieser heterogenen Abfälle recht kompliziert ist. Bauschutt ist ein heterogener, SiO2-reicher Sekundärrohstoff, der sich aus einem Gemisch verschiedener abgebrochener Baumaterialien wie Ziegel, Betonfertigteile, Leichtbeton, Porenbeton, Kalksandsteine, Natursteine, Gips und Mörtel zusammensetzt. Die genaue Zusammensetzung hängt von der Abbruchstelle, der Vorsortierung und der Wiederaufbereitung in der Recyclinganlage ab. Eine direkte Wiederverwendung als rezyklierte Gesteinskörnung ist aufgrund der uneinheitlichen Zusammensetzung und des bis zu 50 %igen Feinanteils nach der mechanischen Aufbereitung nicht zulässig. Eine Möglichkeit, Mauerwerksschutt effektiv zu recyceln, ist die rohstoffliche Verwertung über ein chemisch-hydrothermales Umwandlungsverfahren, das poröse Granulate erzeugt. Durch die Porenstruktur dieser hydrothermal gehärteten Granulate ergeben sich Anwendungsmöglichkeiten als Filter- oder Wasserspeichermaterial, die über den Bausektor hinausgehen. Diese neuartigen Granulate können leichte Gesteinskörnungen natürlichen Ursprungs (z. B. Lavasand, Bimsstein) oder Körner aus natürlichen Rohstoffen (z. B. Blähton) ersetzen. Die neue Recyclingstrategie spart natürliche Ressourcen. Im Vergleich zur Herstellung von Blähton ist der Energieverbrauch wesentlich geringer. Ziel des Verbundprojektes HYTEGRA war die Entwicklung eines Verfahrens zur Herstellung von leichten Gesteinskörnungen aus SiO2- und CaO-reichen Sekundärrohstoffen. Als Rohstoffe wurden Mauerwerksschutt als SiO2-Quelle und Papierasche aus der energetischen Verwertung von Reststoffen der Altpapierverwertung als CaO-Quelle eingesetzt. Der komplette Prozess von der mechanisch-physikalischen Aufbereitung über die Bildung des Grüngranulats bis zur hydrothermalen Härtung wurde entwickelt und im Labormaßstab getestet. Die Anwendungen des hydrothermal gehärteten Granulats als Wasserspeichermaterial für die innere Nachbehandlung von hochfestem Beton, Pflanzensubstrat und Filtermaterial in Bodenfiltern zur Abwasserreinigung wurden untersucht. Der Beitrag gibt einen Überblick über die wichtigsten Ergebnisse des erfolgreich abgeschlossenen Verbundforschungsprojekts HYTEGRA.
T2 - Kolloquium des Arbeitskreises “Energie, Mensch und Zivilisation” - Die Energiewende 2.0 Im Fokus: Die Stoffwirtschaft
CY - Potsdam, Germany
DA - 09.06.2023
KW - Rohstoffliches Recycling
KW - Mauerwerkbruch
KW - Papierasche
KW - leichte Gesteinskörnung
KW - poröse Granulate
KW - hydrothermale Behandlung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593445
UR - https://leibnizsozietaet.de/wp-content/uploads/2023/12/01_SB158-0.pdf
SN - 978-3-86464-252-4
DO - https://doi.org/10.53201/SITZUNGSBERICHTE158
SN - 0947-5850
VL - 158
SP - 79
EP - 94
PB - trafo Wissenschaftsverlag
CY - Berlin
AN - OPUS4-59344
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Küttenbaum, Stefan
T1 - Zur Visualisierung von Schäden in Betonschwellen durch zerstörungsfreie Ultraschallprüfung
N2 - Die bildgebende Ultraschalltechnik liefert Hinweise auf verdeckte Schäden in Spannbetonschwellen. Dieses zerstörungsfreie Prüfverfahren schafft eine objektive und vergleichbare Basis für die Zustandsbestimmung der Schwellen und ermöglicht die Optimierung von baulichen Erhaltungsstrategien.
KW - Spannbetonschwellen
KW - Zustandsbewertung
KW - Verkehrsinfrastruktur
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592914
UR - https://www.eurailpress.de/magazine.html
SN - 0013-2845
IS - 12/23
SP - 26
EP - 31
PB - DVV Media Group
CY - Hamburg
AN - OPUS4-59291
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Küttenbaum, Stefan
T1 - Zur Visualisierung von Schäden in Betonschwellen durch zerstörungsfreie Ultraschallprüfung
N2 - Die bildgebende Ultraschalltechnik liefert Hinweise auf verdeckte Schäden in Spannbetonschwellen. Dieses zerstörungsfreie Prüfverfahren schafft eine objektive und vergleichbare Basis für die Zustandsbestimmung der Schwellen und ermöglicht die Optimierung von baulichen Erhaltungsstrategien.
KW - Betonschwellen
KW - Ultraschall
KW - Schieneninfrastruktur
KW - Gleisoberbau
KW - Spannbetonschwelle
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591889
UR - https://www.eurailpress.de/etr
SN - 0013-2845
IS - 12
SP - 26
EP - 31
PB - DVV Media Group, Eurailpress
CY - Hamburg
AN - OPUS4-59188
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Agrawal, A.
A1 - Tamsen, E.
A1 - Unger, Jörg F.
A1 - Koutsourelakis, P-S
T1 - From concrete mixture to structural design—a holistic optimization procedure in the presence of uncertainties
N2 - We propose a systematic design approach for the precast concrete industry to promote sustainable construction practices. By employing a holistic optimization procedure, we combine the concrete mixture design and structural simulations in a joint, forward workflow that we ultimately seek to invert. In this manner, new mixtures beyond standard ranges can be considered. Any design effort should account for the presence of uncertainties which can be aleatoric or epistemic as when data are used to calibrate physical models or identify models that fill missing links in the workflow. Inverting the causal relations established poses several challenges especially when these involve physicsbased models which more often than not, do not provide derivatives/sensitivities or when design constraints are present. To this end, we advocate Variational Optimization, with proposed extensions and appropriately chosen heuristics to overcome the aforementioned challenges. The proposed approach to treat the design process as a workflow, learn the missing links from data/models, and finally perform global optimization using the workflow is transferable to several other materials, structural, and mechanical problems. In the present work, the efficacy of the method is exemplarily illustrated using the design of a precast concrete beam with the objective to minimize the global warming potential while satisfying a number of constraints associated with its load-bearing capacity after 28 days according to the Eurocode, the demolding time as computed by a complex nonlinear finite element model, and the maximum temperature during the hydration.
KW - Black-box optimization under uncertainty
KW - Mix design
KW - Performance oriented design
KW - Precast concrete
KW - Probabilistic machine learning
KW - Sustainable material design
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615443
DO - https://doi.org/10.1017/dce.2024.18
VL - 5
IS - e20
SP - 1
EP - 32
PB - Cambridge University Press
CY - England
AN - OPUS4-61544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Küttenbaum, Stefan
A1 - Braml, T.
A1 - Taffe, A.
A1 - Keßler, S.
A1 - Maack, Stefan
T1 - Reliability assessment of existing structures using results of nondestructive testing
N2 - Making optimal decisions about the reliability of existing structures requires that the information used in assessment adequately represents the properties and the condition of the structures. The knowledge gap regarding a structure to be assessed can be successively filled by individually purposeful observations on site. This paper gives an overview of an approach for utilizing nondestructively gathered measurement results in reliability assessment of existing structures. An essential part of measurement-based stochastic modeling of basic variables is the calculation of measurement uncertainties, which serves to establish confidence in measurement, to ensure the comparability of unambiguously expressed measurement results, and to quantify the quality of the measured information. Regarding the current discourse on how to treat information collected on-site in the context of assessment, the authors recommend that measurement uncertainty becomes an uncertainty component mandatorily to be represented in measurement-based stochastic models. The main steps of the proposed concept are presented, and the advantages of its application are emphasized by means of a prestressed concrete bridge as case study. The bridge is assessed regarding the serviceability limit state decompression using ultrasonic and radar data measured at the structure.
KW - Bridge
KW - Measurement uncertainty
KW - Prestressed concrete
KW - Stochastic modeling
KW - Probabilistic methods
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529927
DO - https://doi.org/10.1002/suco.202100226
SN - 1751-7648
VL - 22
IS - 5
SP - 2895
EP - 2915
PB - John Wiley & Sons Ltd
CY - Oxford
AN - OPUS4-52992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moreno Torres, Benjami
A1 - Völker, Christoph
A1 - Munsch, Sarah Mandy
A1 - Hanke, T.
A1 - Kruschwitz, Sabine
ED - Tosti, F.
T1 - An Ontology-Based Approach to Enable Data-Driven Research in the Field of NDT in Civil Engineering
N2 - Although measurement data from the civil engineering sector are an important basis for scientific analyses in the field of non-destructive testing (NDT), there is still no uniform representation of these data. An analysis of data sets across different test objects or test types is therefore associated with a high manual effort. Ontologies and the semantic web are technologies already used in numerous intelligent systems such as material cyberinfrastructures or research databases. This contribution demonstrates the application of these technologies to the case of the 1H nuclear magnetic resonance relaxometry, which is commonly used to characterize water content and porosity distri-bution in solids. The methodology implemented for this purpose was developed specifically to be applied to materials science (MS) tests. The aim of this paper is to analyze such a methodology from the perspective of data interoperability using ontologies. Three benefits are expected from this ap-proach to the study of the implementation of interoperability in the NDT domain: First, expanding knowledge of how the intrinsic characteristics of the NDT domain determine the application of semantic technologies. Second, to determine which aspects of such an implementation can be improved and in what ways. Finally, the baselines of future research in the field of data integration for NDT are drawn.
KW - Ontology Engineering
KW - Interoperability
KW - Data-integration
KW - NMR relaxometry
KW - materials informatics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529716
DO - https://doi.org/10.3390/rs13122426
SN - 2072-4292
N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M.
VL - 13
IS - 12
SP - 2426
PB - Multidisciplinary Digital Publishing Institute (MDPI)
CY - Basel, Switzerland
AN - OPUS4-52971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Maack, Stefan
A1 - Schweitzer, T.
A1 - Strangfeld, Christoph
T1 - Enhancing the spectral signatures of ultrasonic fluidic transducer pulses for improved time-of-flight measurements
N2 - Air-coupled ultrasonic (ACU) testing has proven to be a valuable method for increasing the speed in non-destructive ultrasonic testing and the investigation of sensitive specimens. A major obstacle to implementing ACU methods is the significant signal power loss at the air–specimen and transducer–air interfaces. The loss between transducer and air can be eliminated by using recently developed fluidic transducers. These transducers use pressurized air and a natural flow instability to generate high sound power signals. Due to this self-excited flow instability, the individual pulses are dissimilar in length, amplitude, and phase. These amplitude and angle modulated pulses offer the great opportunity to further increase the signal-to-noise ratio with pulse compression methods.
In practice, multi-input multi-output (MIMO) setups reduce the time required to scan the specimen surface, but demand high pulse discriminability. By applying envelope removal techniques to the individual pulses, the pulse discriminability is increased allowing only the remaining phase information to be targeted for analysis. Finally, semi-synthetic experiments are presented to verify the applicability of the envelope removal method and highlight the suitability of the fluidic transducer for MIMO setups.
KW - Air-coupled ultrasound
KW - Fluidics
KW - Signal processing
KW - Pulse compression
KW - MIMO
KW - Hilbert transform
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537853
DO - https://doi.org/10.1016/j.ultras.2021.106612
SN - 0041-624X
VL - 119
SP - 1
EP - 12
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-53785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogler, Nico
A1 - Drabetzki, Philipp
A1 - Lindemann, Mathias
A1 - Kühne, Hans-Carsten
T1 - Description of the concrete carbonation process with adjusted depth resolved thermogravimetric analysis
N2 - The thermal gravimetric analysis (TG) is a common method for the examination of the carbonation progress of cement-based materials. Unfortunately, the thermal properties of some components complicate the evaluation of TG results. Various hydrate phases, like ettringite (AFt), C-S-H and AFm decompose almost simultaneously in the temperature range up to 200 °C. Additionally, physical bound water is released in the same temperature range. In the temperature range between 450 °C and 600 °C the decomposition of calcium hydroxide and amorphous or weakly bound carbonates takes place simultaneously. Carbonates, like calcite, from limestone powder or other additives may be already contained in the noncarbonated sample material. For this research an attempt was made to minimise the influence of these effects. Therefore, differential curves from DTG-results of non-carbonated areas and areas with various states of carbonation of the same sample material were calculated and evaluated. Concretes based on three different types of cement were produced and stored under accelerated carbonation conditions (1 % CO2 in air). The required sample material was obtained by cutting slices from various depth of previously CO2-treated specimen and subsequent grinding. During the sample preparation, a special attention was paid that no additional carbonation processes took place. As reference method for the determination of the carbonation depth the sprayed application of phenolphthalein solution was carried out. Microscopic analysis where examined to confirm the assumptions made previously. Furthermore, the observed effect of encapsulation of calcium hydroxide by carbonates caused by the accelerated carbonation conditions was examined more closely.
KW - Microscopy
KW - Accelerated carbonation
KW - Carbonation behaviour
KW - Concrete
KW - Thermal Analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530571
DO - https://doi.org/10.1007/s10973-021-10966-1
VL - 147
IS - 11
SP - 1
EP - 14
PB - Springer
AN - OPUS4-53057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hüsken, Götz
A1 - Pirskawetz, Stephan
A1 - Hofmann, Detlef
A1 - Basedau, Frank
A1 - Gründer, Klaus-Peter
A1 - Kadoke, Daniel
T1 - The load-bearing behaviour of a reinforced concrete beam investigated by optical measuring techniques
N2 - Bending beams and slabs are typical examples for structural elements used for reinforced concrete structures such as bridge girders, T-beams and bridge decks. Their strength related failure modes at maximum loading can be divided into bending and shear failure. The failure of beams loaded in bending can occur with or without indication. Therefore, conventional design concepts aim on failure modes with sufficient indication (e.g. large deflections or cracks), as it occurs in the case of secondary flexural compression failure. These indicating factors can also be used for Structural Health Monitoring (SHM) of civil infrastructure systems (e.g. bridges) to identify structural changes. In this context, non-destructive testing (NDT) methods offer different techniques for measuring deflections or crack formation and opening. However, profound knowledge on the determining failure modes of bending beams and their detection by NDT methods is required for the reliable application of SHM. Different NDT methods have been used in this study for analysing the load-bearing behaviour of a reinforced concrete beam in bending. The different measuring techniques are briefly described and their applicability is discussed by means of experimental results. For this purpose, the load-bearing behaviour of a reinforced concrete beam having a span of 2.75 m was investigated in a four-point bending flexural test at laboratory scale. The focus is on the characterization of determining failure modes by optical NDT and the comparison with classical measuring techniques (e.g. deformation measurements by displacement transducers). The bending beam was equipped with two single-mode (SM) sensor fibres. One fibre served as Distributed Optical Fibre Sensor (DOFS), whereas the other fibre contained Fibre Bragg Grating (FBG) sensors. In addition, optical deformation measurements using Digital Image Correlation (DIC) and Stereophotogrammetry (SP) were conducted.
KW - Concrete beam
KW - Bending
KW - Digital image correlation
KW - Stereophotogrammetry
KW - Distributed fibre optic sensor
KW - Fibre bragg grating
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524762
DO - https://doi.org/10.1617/s11527-021-01699-6
VL - 54
IS - 3
SP - Article 102
PB - Springer
AN - OPUS4-52476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigel, Sandra
A1 - Gehrke, M.
A1 - Recknagel, Christoph
A1 - Stephan, D.
T1 - Identification and quantification of additives in bituminous binders based on FTIR spectroscopy and multivariate analysis methods
N2 - Bitumen is a crucial building material in road construction, which is exposed to continuously higher stresses due to higher traffic loads and changing climatic conditions. Therefore, various additives are increasingly being added to the bitumen complicating the characterisation of the bituminous binder, especially concerning the reuse of reclaimed asphalt.
Therefore, this work aimed to demonstrate that the combination of Fourier transform infrared (FTIR) spectroscopy with attenuated total reflexion (ATR) technique and multivariate evaluation is a very wellsuited method to reliable identify and quantify additives in bituminous binders. For this purpose, various unmodified and modified binders, directly and extracted from laboratory and reclaimed asphalts, were investigated with FTIR-ATR spectroscopy. The determined spectra, pre-processed by standard normal variate (SNV) transformation and the determination of the 1st derivation, were evaluated using factor Analysis (FA), linear discriminant analysis (LDA) and partial least square regression (PLSR). With this multivariate evaluation, first, a significant model with a very high hit rate of over 90% was developed allowing for the identification of styrene-butadiene copolymers (SBC), ethylene-copolymer bitumen (ECB) and different waxes (e.g. amide and Fischer-Tropsch wax) even if the additives do not show any additional peaks or the samples are multi-modified. Second, a quantification of the content is possible for SBC, ECB, and Amide wax with a mean error of RMSE B 0.4 wt% and a
coefficient of determination of R2[90%. Based on these results, FTIR identification and quantification of additives in bituminous binders is a very promising method with a great potential.
KW - Bituminous binders
KW - FTIR-ATR
KW - Multivariate evaluation
KW - Identification and quantification of additives
KW - Polymers
KW - Waxes
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534877
DO - https://doi.org/10.1617/s11527-021-01763-1
VL - 54
IS - 4
SP - 1
EP - 9
PB - Springer
AN - OPUS4-53487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Maack, Stefan
A1 - Schönsee, Eric
A1 - Schweitzer, Thorge
A1 - Strangfeld, Christoph
T1 - Acoustic and flow data of fluidic and piezoelectric ultrasonic transducers
N2 - This data article presents characteristic acoustic and flow data of a fluidic ultrasonic transducer as well as acoustic data of a commercial piezoelectric ultrasonic transducer used in non-destructive testing for civil engineering. The flow data has been acquired using hot-wire anemometry and a Pitot tube. The three-dimensional acoustic data of both devices has been acquired using a calibrated microphone. The distribution of characteristic acoustic properties of both transducers are extracted and given in addition to the raw data. The data presented in the article will be a valuable source for reference and validation, both for developing fluidic and alternate ultrasound generation technologies. Furthermore, they will give additional insight into the acoustic-flow interaction phenomena of high speed switching devices. This article is accompanying the paper Experimental Analysis of the Acoustic Field of an Ultrasonic Pulse Induced by a Fluidic Switch (Bühling et al., 2021) published in The Journal of the Acoustical Society of America, where the data is interpreted in detail and the rationale for characteristic sound properties of the fluidic transducer are given.
KW - Ultrasound
KW - Non-destructive testing
KW - Air-coupled ultrasound
KW - Fluidics
KW - Acoustic-flow interaction
KW - Piezoelectric transducer
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531308
DO - https://doi.org/10.1016/j.dib.2021.107280
VL - 38
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53130
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Wiehle, Philipp
A1 - Munsch, Sarah Mandy
T1 - About the dominance of mesopores in physisorption in amorphous materials
N2 - Amorphous, porous materials represent by far the largest proportion of natural and men-made materials. Their pore networks consists of a wide range of pore sizes, including mesoand macropores. Within such a pore network, material moisture plays a crucial role in almost all transport processes. In the hygroscopic range, the pores are partially saturated and liquid water is only located at the pore fringe due to physisorption. Therefore, material parameters such as porosity or median pore diameter are inadequate to predict material moisture and moisture transport. To quantify the spatial distribution of material moisture, Hillerborg’s adsorption Theory is used to predict the water layer thickness for different pore geometries. This is done for all pore sizes, including those in the lower nanometre range. Based on this approach, it is shown that the material moisture is almost completely located in mesopores, although the pore network is highly dominated by macropores. Thus, mesopores are mainly responsible for the moisture storage capacity, while macropores determine the moisture transport capacity, of an amorphous material. Finally, an electrical analogical circuit is used as a model to predict the diffusion coefficient based on the pore-size distribution, including physisorption.
KW - Physisorption
KW - Mesopores
KW - Amorphous materials
KW - Macropores
KW - Adsorbed water layer thickness
KW - Material moisture
KW - Moisture distribution
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538525
UR - https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/NILGW2
DO - https://doi.org/10.3390/molecules26237190
VL - 26
IS - 23
SP - 1
EP - 22
PB - MDPI
AN - OPUS4-53852
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Küttenbaum, Stefan
A1 - Maack, Stefan
A1 - Strangfeld, Christoph
T1 - Development of an Accurate and Robust Air-Coupled Ultrasonic Time-of-Flight Measurement Technique
N2 - Ultrasonic time-of-flight (ToF) measurements enable the non-destructive characterization of material parameters as well as the reconstruction of scatterers inside a specimen. The time-consuming and potentially damaging procedure of applying a liquid couplant between specimen and transducer can be avoided by using air-coupled ultrasound. However, to obtain accurate ToF results, the waveform and travel time of the acoustic signal through the air, which are influenced by the ambient conditions, need to be considered. The placement of microphones as signal receivers is restricted to locations where they do not affect the sound field. This study presents a novel method for in-air ranging and ToF determination that is non-invasive and robust to changing ambient conditions or waveform variations. The in-air travel time was determined by utilizing the azimuthal directivity of a laser Doppler vibrometer operated in refracto-vibrometry (RV) mode. The time of entry of the acoustic signal was determined using the autocorrelation of the RV signal. The same signal was further used as a reference for determining the ToF through the specimen in transmission mode via cross-correlation. The derived signal processing procedure was verified in experiments on a polyamide specimen. Here, a ranging accuracy of <0.1 mm and a transmission ToF accuracy of 0.3μs were achieved. Thus, the proposed method enables fast and accurate non-invasive ToF measurements that do not require knowledge about transducer characteristics or ambient conditions.
KW - Air-coupled ultrasound
KW - Laser Doppler vibrometer
KW - Refracto-vibrometry
KW - Acousto-optic effect
KW - Time-of-flight measurements
KW - In-air ranging
KW - Non-destructive testing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544711
DO - https://doi.org/10.3390/s22062135
VL - 22
IS - 6
SP - 1
EP - 17
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-54471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bühling, Benjamin
A1 - Maack, Stefan
A1 - Strangfeld, Christoph
T1 - OsciCheck - A Novel Fluidic Transducer for Air-Coupled Ultrasonic Measurements
N2 - Ultrasonic measurement technology has become indispensable in NDT-CE. Air-coupled ultrasonic (ACU) measurement techniques promise to reduce measurement time. However, the signal quality suffers from large specific impedance mismatch at the transducer-air and air-specimen interface. Additionally, large pressure amplitudes are necessary for the penetration depth required in NDT-CE applications. To address the specific requirements of ultrasonic testing in NDT-CE, a robust ACU transducer was developed, that generates ultrasound by quickly switching a pressurized air flow. The simple design of the fluidic transducer makes the device maintenance free and resilient against harsh environmental conditions. Since the signal is generated by aeroacoustics, there is no specific impedance mismatch between the transducer and the surrounding air. The ultrasonic signal exhibits frequencies in the 30-60 kHz range and is therefore well suited to penetrate heterogenous materials such as concrete. This contribution gives an introduction in the working principle and signal characteristics of the fluidic transducer. Its applicability to measurements in concrete is verified. A detailed outlook is given to discuss the future potential of fluidic ultrasonic actuators.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Air-coupled ultrasound
KW - Nondestructive testing
KW - Fluidics
KW - Bistable amplifier
KW - Aeroacoustics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555271
UR - https://www.ndt.net/search/docs.php3?id=27319
VL - 2022/09
SP - 1
EP - 9
PB - NDT.net
CY - Bad Breisig
AN - OPUS4-55527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strangfeld, Christoph
A1 - Schönsee, Eric
A1 - Jeyifous, Olubunmi Anthony
A1 - Izanlu, Morteza
A1 - Hüsken, Götz
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - In situ Prozessüberwachung und Qualitätskontrolle bei der additiven Fertigung von Betonbauteilen
N2 - In der additiven Fertigung von Beton wird kontinuierlich Material gemischt und verarbeitet. Dies erfordert eine kontinuierliche in situ Prozessüberwachung und Qualitätskontrolle. An der BAM wurde ein 3D-Betondrucker aufgebaut, der eine umfängliche Prozessüberwachung ermöglicht. Druck-, Temperatur- und Feuchtesensoren in der Pumpe und im Fördersystem erlauben ein kontinuierliches Monitoring des Frischbetons, während ein Laserlinienscanner am Druckkopf unmittelbar die gedruckte Ist-Kontur verfolgt. Die so gewonnenen Daten können Grundlage für die Erarbeitung von Normen für die additive Fertigung von Betonbauteilen sein und somit deren Standsicherheit gewährleisten.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - In situ
KW - Prozessüberwachung
KW - Additive Fertigung
KW - Betonbauteil
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613064
SN - 978-3-9818564-7-7
SP - 138
EP - 146
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61306
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rübner, Katrin
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Vom Bauschutt zur leichten Gesteinskörnung
N2 - Leichte Gesteinskörnungen können ressourcenschonend aus heterogenen und feinkörnigen Bau- und Abbruchabfällen in einem mehrstufigen Prozess durch thermische oder hydrothermale Stoffumwandlung hergestellt werden. Ihre Anwendung erfolgt in Leichtbetonen und Leichtmörteln, als Schüttung im Garten und Landschaftsbau oder auch als Filter- und Speichermaterial. In zahlreichen Forschungsprojekten wurden die Herstellungsprozesse entwickelt, die Materialeigenschaften optimiert und unterschiedliche Applikationen untersucht. In diesem Beitrag wird zusammenfassend über dieser Forschungsarbeiten berichtet.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Bauschutt
KW - Gesteinskörnung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613105
SN - 978-3-9818564-7-7
SP - 70
EP - 77
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61310
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cook, Jake
A1 - Tonon, Chiara
A1 - Stohl, Leonie
A1 - von Werder, Julia
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Assessment of concrete bioreceptivity and model organism performance for use in algal biofilm green facade systems
N2 - Elevated temperatures and high levels of air pollution in urban environments pose a significant threat to the health and life quality of inhabitants of these areas. This research aims to address these challenges by developing green façade systems using micro-algal biofilms. Both material and biological properties are assessed to optimise biofilm performance and durability. Cementitious samples with different pH levels and varying nutrient compositions are tested in combination with model microorganisms. Organism growth, health and adhesion are monitored over a 3-month period under controlled laboratory conditions.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Concrete bioreceptivity
KW - Model organism performance
KW - Algal biofilm
KW - Algal biofilm green facade systems
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613114
SN - 978-3-9818564-7-7
SP - 159
EP - 166
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Robens-Radermacher, Annika
A1 - Saif-Ur-Rehman,
A1 - Wolf, Christoph
A1 - Kujath, Cezary
A1 - He, Yuxiang
A1 - Mezhof, Alexander
A1 - Hüsken, Götz
A1 - Jeyifous, Olubunmi Anthony
A1 - Unger, Jörg F.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Modellierung und Simulation von 3D Betondruck – Design- und Prozessoptimierung
N2 - Der 3D Betondruck ermöglicht die effiziente und ressourcenschonendere Herstellung maßgeschneiderter Betonstrukturen. Trotz des großen Potentials gibt es bisher keine einheitlichen Normen und Standards für den sicheren und robusten 3D Betondruck. Der Beitrag zeigt das Potential numerischer Methoden und Modelle zur effizienten und ressourcenschonenden Design- und Prozessoptimierung des 3D Betondrucks. Dazu werden die aktuellen Forschungsarbeiten im Bereich der Entwicklung robuster und zuverlässiger numerischer Zwillinge, geeigneter Optimierungstools sowie digitaler Workflows diskutiert.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Modellierung
KW - Simulation
KW - 3D Betondruck
KW - Designoptimierung
KW - Prozessoptimierung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613023
SN - 978-3-9818564-7-7
SP - 132
EP - 137
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61302
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Andrés Arcones, Daniel
A1 - Unger, Jörg F.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Modell- und Parameterunsicherheiten am Beispiel eines digitalen Brückenzwillings
N2 - Digitale Zwillinge bieten wertvolle Einblicke in das Verhalten von Bauwerken und ermöglichen eine fundierte Entscheidungsfindung. Durch den Einsatz von Simulationen, die auf physikalischen Gesetzen beruhen, ist es möglich, Vorhersagen über die Struktur auf der Grundlage zukünftiger oder hypothetischer Situationen zu treffen. Die Verwendung solcher Simulationen impliziert jedoch eine Reihe von Annahmen und Vereinfachungen, die unvermeidbare Fehler in die Vorhersagen einbringen. Die Quantifizierung dieser Unsicherheiten ist der Schlüssel für den Einsatz zuverlässiger digitaler Zwillinge von Brücken.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Modellunsicherheit
KW - Parameterunsicherheit
KW - Digitaler Brückenzwilling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613013
SN - 978-3-9818564-7-7
SP - 218
EP - 223
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61301
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüsken, Götz
A1 - Jeyifous, Olubunmi Anthony
A1 - Schönsee, Eric
A1 - Strangfeld, Christoph
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Beitrag zur Beurteilung der Wiederholbarkeit additiv gedruckter Betonbauteile
N2 - Die additive Fertigung von Betonbauteilen, auch bekannt als 3D-Betondruck, ist eine Technologie, die im letzten Jahrzehnt aufgrund ihrer finanziellen und ökologischen Vorteile als nachhaltige Fertigungstechnologie viel Aufmerksamkeit erhalten hat. Obwohl die Vorteile der additiven Fertigung bereits durch zahlreiche Forschungs- und Demonstrationsprojekte gezeigt wurden, ist die Qualitätskontrolle während des Druckens äußerst anspruchsvoll und wird auch aufgrund fehlender harmonisierter Normen kaum angewendet. Aufgrund des kontinuierlichen Mischprozesses beim 3D-Betondruck ist es unmöglich Schwankungen des Trockenmörtels oder des Wassergehalts auszuschließen. Daher ist eine einzelne Stichprobe nicht mehr repräsentativ für das gesamte Bauteil und ein während des Druckens in einer Schicht auftretender Fehler kann die Integrität der gesamten Struktur beeinträchtigen. In diesem Beitrag werden die Ergebnisse eines als Fachwerkstruktur konzipierten Bogens, der unter vergleichbaren Randbedingungen mehrmals mit einem 3D-Betonextrusionsdrucker gedruckt wurde, vorgestellt. Jeder Bogen wurde auf seine mechanische Festigkeit und sein Tragverhalten geprüft. Die Ergebnisse der mechanischen Prüfungen der gedruckten Bögen werden mit Materialdaten aus klassischen Materialprüfungen verglichen und hinsichtlich ihrer statistischen Signifikanz diskutiert.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Additiv gedrucktes Betonbauteil
KW - Beurteilung
KW - Wiederholbarkeit
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613043
SN - 978-3-9818564-7-7
SP - 126
EP - 131
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61304
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Trattnig, H.
A1 - Boehm, C.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Spanndrahtbrüche und ihr digitaler akustischer Zwilling
N2 - Die Planung eines Monitorings von Spanndrahtbrüchen mit Schallemissionsanalyse erfordert viel Erfahrung und setzt eine akustische Analyse der Spannbetonstruktur voraus. Eine akustische Simulation der Struktur unterstützt die Optimierung der Sensoranordnung und erhöht die Zuverlässigkeit der Drahtbrucherkennung durch die Fusion von Simulations- und Messergebnissen in einer Datenbank. Künftig können Baulastträger und Monitoringanbieter von standardisierten – FAIR-en – akustischen Daten profitieren.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Spanndrahtbruch
KW - Digitaler akustischer Zwilling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613038
SN - 978-3-9818564-7-7
SP - 224
EP - 229
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61303
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stohl, Leonie
A1 - Cook, Jake
A1 - von Werder, Julia
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Bioreceptive concrete surfaces: Understanding material-biology interactions for façade greening
N2 - The climate crisis has led to a growing demand for environmentally oriented approaches in the construction industry, including not only eco-friendly materials, but also the greening of urban spaces. Microbial facade greening with algae is a novel concept based on the inherent bioreceptive properties of different building materials. This study focuses on the influence of physical material properties on biofilm formation. Differently textured samples from the same UHPC mix were produced and their roughness and water absorption documented. The samples were then weathered under laboratory conditions to observe material-algae interactions.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Bioreceptive
KW - Material-biology Interaction
KW - Façade greening
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613096
SN - 978-3-9818564-7-7
SP - 153
EP - 158
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61309
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weise, Frank
A1 - Kühnel, Alena
A1 - Fladt, Matthias
A1 - Stelzner, Ludwig
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Dauerhaftigkeit von Betonfahrbahndecken im deutschen Bundesautobahnnetz
N2 - Die Dauerhaftigkeit der Betondecke und deren Oberflächentexturierung bestimmen maßgebend das Ge-brauchsverhalten von Betonfahrbahnen. Der Beitrag zeigt die Leistungsfähigkeit der Innenhydrophobierung als neuartige AKR-Vermeidungsstrategie zur Sicherstellung der geplanten, normativen Nutzungsdauer, auch unter Verwendung grenzwertig alkaliempfindlicher Gesteinskörnungen, auf. Zusätzlich wird eine neuartige Prüfmethodik zur in situ Verfolgung der 3D-Texturveränderungen auf einem erneuerten BAB-Abschnitt mit Grindingtextur vorgestellt. Diese beeinflussen maßgebend die Griffigkeit und die Reifen-Fahrbahn-Geräusche.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Betonfahrbahnen
KW - Alkali-Kieselsäure-Reaktion
KW - Innenhydrophobierung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613184
SN - 978-3-9818564-7-7
SP - 232
EP - 243
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61318
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Recknagel, Christoph
A1 - Weigel, Sandra
A1 - Hoppe, Johannes
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Dauerhafte Funktionsfähigkeit von Bauwerksfugen - Das performance concept in der Abdichtungstechnik von Betonfahrbahnen
N2 - Verlässliche Funktionsfähigkeit und planbare Lebensdauerzyklen sind entscheidend für die Weiterentwicklung der Betonbauweise im Straßenbau. Aus Forschungsergebnissen zur Fugenproblematik in hochbeanspruchten Betonfahrbahnen unter Diskussion regelungsspezifischer Erfordernisse erfolgt ein Plädoyer für eine funktionsanalytische Untersuchung von Fugensystemen. Mit aktuellen Projekten werden die Datengrundlage zu maßgebenden Einwirkungen und eine innovative versuchstechnische Infrastruktur als methodische Voraussetzungen zur Erhöhung zuverlässiger Funktionsfähigkeit von Bauwerksfugen bereitgestellt.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Betonfahrbahnen
KW - Bauwerksfugen
KW - Abdichtungstechnik von Betonfahrbahnen
KW - SensoJointField
KW - INFUKON
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613207
SN - 978-3-9818564-7-7
SP - 244
EP - 252
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61320
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Weigel, Sandra
A1 - Recknagel, Christoph
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Ein Ausblick: Alternative Bindemittel für bitumenhaltige Materialien
N2 - Im Straßen- und Ingenieurbau sind neben dem Baustoff Beton auch bitumenhaltige Materialien in Flächenab-dichtungen, Dehnfugenkonstruktionen und Asphaltbelägen von entscheidender Bedeutung. Die bestehende Erdölabhängigkeit dieser Materialien fordert jedoch ein dringendes Umdenken, wobei langfristig die Substitu-tion des Bitumens durch nachhaltige, biobasierte Alternativmaterialien angestrebt werden sollte. Durch eine partielle Substitution wäre zudem bereits kurz- bis mittelfristig eine Reduzierung der Erdölabhängigkeit mög-lich, wobei sich z.B. Rückstände der Mikroalgenaufbereitung oder Lignin als Substitutionsprodukte eignen.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Alternative
KW - Bindemittel
KW - Bitumenhaltige Materialien
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613138
SN - 978-3-9818564-7-7
SP - 167
EP - 174
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61313
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pittrich, Tim
A1 - Stelzner, Ludwig
A1 - Weise, Frank
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Tunnelbrand – Abplatzverhalten von normalfesten Betonen mit verschiedenen klinkereffizienten Zementen
N2 - Zur Verminderung der CO2-Emissionen der Bauindustrie gewinnen klinkereffiziente Zemente immer mehr an Bedeutung und werden vermehrt in Ingenieurbauwerken eingesetzt. Das brandinduzierte Abplatzverhalten von Betonen mit diesen Zementen ist allerdings nur bedingt bekannt und ist u.a. im Tunnelbau von hoher Bedeutung. Im Zuge dessen, wurden normalfeste Betone mit vier verschiedenen Zementen (CEM I, CEM II/A-LL, CEM III/A und CEM II/B-Q) auf ihr brandinduziertes Abplatzverhalten untersucht. Die Ergebnisse zeigen, dass Betone mit klinkereffizienten Zementen zu stärkeren Abplatzungen neigen.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Verminderung CO2-Emissionen
KW - Brandinduziertes Abplatzverhalten
KW - Klinkereffiziente Zemente
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613215
SN - 978-3-9818564-7-7
SP - 253
EP - 262
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61321
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bednarska, Dalia
A1 - von Werder, Julia
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Modification of clay-based materials with a novel geopolymer: potential application towards water-resistance
N2 - Earth is probably the most eco-friendly building material. However, since earthen materials dissolve in water easily their application is limited. The presented manuscript aims to verify the usefulness of a one-part geo- polymer developed at BAM as a stabilizing agent for earthen mortars. The experimental study encompasses water-resistance, compressive strength, linear shrinkage, water vapour permeability and microstructural anal- ysis of the reference and the modified earthen plaster. The presented results show that the modification visibly affects the properties of the initial material providing its water-resistance.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Clay-based materials
KW - Water-resistance
KW - Novel geopolymer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613150
SN - 978-3-9818564-7-7
SP - 94
EP - 101
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hille, Falk
A1 - Herrmann, Ralf
A1 - Schneider, Ronald
A1 - Pitters, S.
A1 - Wedel, F.
A1 - Hindersmann, I.
T1 - Developing a guideline for structural health monitoring of road bridges in Germany
N2 - In recent years, Structural Health Monitoring (SHM) has become a useful and increasingly widely used tool for supporting lifetime extensions of existing bridges with known structural deficiencies or indications of potentially critical damages or damage processes.
At the same time, methods and tools are emerging, which enable monitoring-informed predictive maintenance of new and existing bridges based on digital twins. The monitoring process – starting from the definition of monitoring actions and ending with decisions based on monitoring outcomes – is complex and requires expertise in structural engineering, operation and maintenance of bridges, metrology, and data analytics. To support German road authorities, engineering consultancies, building contractors and other stakeholders of the bridge management, the Federal Highway Research Institute (BASt) has initiated the development of a new guideline for applying SHM as part of the management of road bridges. The guideline will present various use cases and for each identified use case, it will propose a proven monitoring scheme. In addition, the guideline will provide guidance on assessing the benefits of SHM as well as a common approach to managing monitoring data as a systematic basis for integrating monitoring data in the bridge management. This contribution discusses the motivation, objectives, and scope of the guideline, describes its use case centric structure and outlines the proposed data management.
T2 - IABMAS 2024
CY - Kopenhagen, Danmark
DA - 24.06.2024
KW - Guideline
KW - Structural health monitoring
KW - Road bridges
KW - Infrastructure
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613947
SN - 978-1-032-77040-6
DO - https://doi.org/10.1201/9781003483755-236
SP - 2009
EP - 2017
PB - CRC Press
AN - OPUS4-61394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Neugum, Tim
A1 - Stelzner, Ludwig
A1 - Häßler, Dustin
A1 - Hothan, Sascha
A1 - Zehfuß, J.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Feuerwiderstand gezwängter Stahlbetonstützen
N2 - Bei realen Brandereignissen stellen sich in der Regel mechanische und thermische Randbedingungen ein, die deutlich von denen in präskriptiven, bauteilorientierten Brandprüfungen abweichen. Beispielsweise werden Interaktionen der brandbeanspruchten Bauteile mit dem umgebenden Tragwerk und daraus resultierende Zwangsbeanspruchungen bei konventionellen Brandprüfungen nicht berücksichtigt. Mit Hilfe der Substrukturtechnik kann das Verhalten einer Stütze im Brandfall unter Berücksichtigung der Interaktion mit dem umgebenden Tragwerk untersucht werden.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Brandprüfungen
KW - Substrukturtechnik
KW - Zwangsbeanspruchungen
KW - Brandbeanspruchung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613249
SN - 978-3-9818564-7-7
SP - 270
EP - 277
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61324
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thiele, Marc
A1 - Herrmann, Ralf
A1 - Degener, Sebastian
A1 - Pirskawetz, Stephan
A1 - Loewe, Anna
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Monitoring an Türmen von Onshore Windenergieanlagen in Betonbauweise im Hinblick auf Ermüdung
N2 - Der Beitrag stellt das Messkonzept sowie dessen Umsetzung für ein umfassendes Monitoringsystem an einer onshore Windenergieanlage mit einem Hybridturm vor. Dieses ist Bestandteil des Forschungsvorhabens Win-ConFat – Structure, welches neben der Validierung geeigneter Sensorik auch die Bewertung des Zustands und der möglichen Restlebensdauer der ermüdungsbeanspruchten Betonstruktur zum Ziel hat. Neben dem Monitoringsystem werden erste Messergebnisse aus den Betriebsdaten sowie vom Verhalten der Turmstruktur vorgestellt.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Monitoring
KW - Windenergieanlage und Hybridturm
KW - Ermüdung
KW - WinConFat – Structure
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613276
SN - 978-3-9818564-7-7
SP - 286
EP - 293
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61327
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hering, Marcus
A1 - Fiedler, Georg
A1 - Schubert, T.
A1 - Hille, Falk
A1 - Hüsken, Götz
A1 - Beckmann, B.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Großmaßstäbliche Impaktversuche mit Stahlbetonplatten – Konzeptionierung und Vorbereitung
N2 - Seit 1977 ist der Flugzeugabsturz ein wesentliches Belastungsszenario bei der Auslegung von Kernkraftwerken. Zur Untersuchung dieses Szenarios wurden umfassende Studien durchgeführt, welche die Reaktion von Stahlbetonkonstruktionen unter Stoßbelastung analysieren. Da großmaßstäbliche Experimente teuer und aufwendig sind, gewinnen skalierte Versuche zunehmend an Bedeutung. Im Rahmen eines Forschungsprojekts der TU Dresden und der BAM wurden Grundlagen für skalierte Impaktversuche im großen Maßstab geschaffen, um die Übertragbarkeit vom Labor- auf Realmaßstab zu ermöglichen.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Fallturm
KW - Impakt
KW - Stahlbetonbauteile
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613257
SN - 978-3-9818564-7-7
SP - 278
EP - 285
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61325
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Deresse, N. E.
A1 - Thiele, Marc
A1 - Pirskawetz, Stephan
A1 - Sarem, M.
A1 - Francois, St.
A1 - Verstrynge, E.
T1 - Evaluation of Concrete Fatigue Damage with Elastic Wave-based Measurement Techniques
N2 - The fatigue damage evolution and the fatigue life of quasi-brittle materials such as concrete are not yet completely understood. Accordingly to get better insights, researchers have recently been incorporating advanced measuring techniques in their fatigue experiments. In this research, acoustic emission techniques (AET), active ultrasonic, and deformation measurements are used to track the damage evolution of concrete samples subjected to fatigue loading. The samples are subjected to constant amplitude and stepwise fatigue loading in Brazilian splitting test set-ups. Initially, a good agreement is observed between the deformation and the ultrasonic measurements in capturing the crack propagation during Brazilian splitting tests. The three fatigue damage phases could be identified with all of the three techniques. The Phase II damage rates quantified by deformation measurements and AET in stepwise fatigue tests were used to predict the number of cycles to failure at various stress
levels. The predictions were validated using the number of cycles to failure of the constant amplitude fatigue tests.
T2 - 36th Conference of the European Working Group on Acoustic Emission
CY - Potsdam, Germany
DA - 18.09.2024
KW - Concrete
KW - Acoustic emission
KW - Ultrasonic testing
KW - Fatigue
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615677
DO - https://doi.org/10.58286/30228
SN - 1435-4934
VL - 29
IS - 10
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-61567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stelzner, Ludwig
A1 - Eiz Eddin, Ahmad
A1 - Häßler, Dustin
A1 - Hothan, Sascha
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Zum Feuerwiderstand von filigranen Deckenelementen aus vorgespanntem Carbonbeton
N2 - Der Einsatz von hoch zugbeanspruchbarem und korrosionsbeständigem Carbongelege anstelle herkömmlichen Spannstahls ermöglicht es Beton vorzuspannen und gleichzeitig die Betondeckung auf ein für den Verbund nötiges Minimum zu reduzieren. Der Wechsel von massiven zu filigranen Bauteilen führt in der Regel aufgrund der geringeren thermischen Masse zu einer Abnahme des Feuerwiderstandes. Der Beitrag stellt Versuchsergebnisse zum Abplatzverhalten von Carbonbeton vor, die im Rahmen des Verbundvorhabens „Vorgespannte Carbonbetondecken mit reduzierten Querschnitten“ (CaPreFloor) erzielt wurden.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Feuerwiderstand
KW - Carbonbeton
KW - Abplatzverhalten
KW - CaPreFloor
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613221
SN - 978-3-9818564-7-7
SP - 263
EP - 269
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61322
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krüger, Miriam E.
A1 - Hilbig, Harald
A1 - Stelzner, Ludwig
A1 - Machner, Alisa
T1 - Effect of the chemical composition of synthetic alkali-silica gels on their structure, swelling behavior and water uptake
N2 - For alkali-silica reaction (ASR) gels, the relationship between swelling expansion, structure and chemical composition, particularly the effect of aluminum, remains unknown. This study investigates the structure, swelling expansion and associated water uptake of synthetic ASR gels with various Al/Si (0–0.1) and Ca/Si (0.1–0.4) ratios. The results show that aluminum incorporated into the gel structure reduces the overall swelling expansion and the leaching of silicate species during the swelling test. Moreover, they revealed that water in the Al-ASR gels is more tightly bound, reducing the overall water uptake compared to the Al-free ASR gels. Additionally, there is a linear correlation between the maximal swelling results and the ASR gel composition.
However, no direct correlation emerged between the amount of water uptake and the free swelling of the ASR gels, which indicates that other factors, like the type of water bonding and pore size of the gels, are decisive for the swelling mechanism.
KW - Concrete
KW - Alkali-silica reaction (ASR)
KW - Durability
KW - 1H NMR relaxometry
KW - 29Si NMR
KW - 27Al NMR
KW - FTIR
KW - Al-ASR gel
KW - Swelling test
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624268
DO - https://doi.org/10.1016/j.cemconres.2024.107596
VL - 184
SP - 1
EP - 18
PB - Elsevier B.V.
AN - OPUS4-62426
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fürst, Richard
A1 - Häßler, Dustin
A1 - Stelzner, Ludwig
A1 - Hothan, Sascha
T1 - Fire resistance of existing steel structures with aged intumescent coating based on an in situ test method
N2 - Intumescent coatings are commonly used in civil engineering to increase the fire resistance of steel structures. Exposed to fire, the intumescent coating reacts and forms a thermal protective char around the steel member. Thus, the heating of the steel is significantly slowed down and the fire resistance can be improved. Information regarding the scope of application and the durability of intumescent coatings are given in national approvals or European Technical Assessment documents. Due to the environmental conditions, intumescent coatings are subjected to ageing effects, which can reduce the durability and their thermal protection performance. To predict the durability for several years, during the approval procedure the behaviour of intumescent coatings is predominantly extrapolated based on accelerated artificial ageing. The established German and European assessment procedures to test and assess durability assume a working life of at least 10 years. Additional evidence may be required for longer periods. However, at present there is no method of verifying the thermal performance of existing structural members on site. For this reason, BAM is conducting the research project "INSIST" [1] to develop a minimally invasive in situ test method to determine the fire resistance of existing steel structures with applied intumescent coating. The investigation includes the development of a mobile prototype furnace. The paper describes the test setup, the developed prototype furnace, and the results of the performed test programme on uncoated and coated steel specimens. Based on this, recommendations for the test procedure are given.
KW - In situ testing
KW - Fire resistance
KW - Intumescent coating
KW - Steel
KW - Thermal protection
KW - Durability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629533
DO - https://doi.org/10.1016/j.firesaf.2025.104380
VL - 153
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-62953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferrier, Emmanuel
A1 - Michel, Laurent
A1 - Thiele, Marc
A1 - Mercier, Julien
T1 - Strain-rate effect on the bond strength of external bonded reinforced carbon fiber-reinforced polymer for concrete structure
N2 - The aim of the presented study is to investigate the dynamic loading strength of an external bonded fiber-reinforced polymers (FRP) system under seismic loading. 16 bonded FRP samples under different loading speeds ranging as 0.0000167–0.8 m /s were examined to determine the characteristics of the FRP bond strength on the concrete. The mechanical tests involved measuring the concrete/FRP shear properties using a double-lap shear test. Sixteen concrete specimens were cast, strengthened and surface preparation, instrumented, and driven to failure in the LMC laboratory and the BAM laboratory (Germany). Dynamic loading increased the bonded strength mainly because of an increase in the concrete tensile strength. Experimental data are then analysed and competed with the equation given by the new European standard that develop the design of external bonded FRP. The characteristic properties and bonded strength obtained by design equation were compared. Based on the results design equation are modified.
KW - EBR strengthening system
KW - Desing bond strength
KW - Durability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625354
DO - https://doi.org/10.1016/j.conbuildmat.2025.140216
SN - 1879-0526
VL - 466
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-62535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andrés Arcones, Daniel
A1 - Weise, M.
A1 - Koutsourelakis, P-S.
A1 - Unger, Jörg F.
T1 - Bias Identification Approaches for Model Updating of Simulation-based Digital Twins of Bridges
N2 - Simulation-based digital twins of bridges have the potential not only to serve as monitoring devices of the current state of the structure but also to generate new knowledge through physical predictions that allow for better-informed decision-making. For an accurate representation of the bridge, the underlying models must be tuned to reproduce the real system. Nevertheless, the necessary assumptions and simplifications in these models irremediably introduce discrepancies between measurements and model response. We will show that quantifying the extent of the uncertainties introduced through the models that lead to such discrepancies provides a better understanding of the real system, enhances the model updating process, and creates more robust and trustworthy digital twins. The inclusion of an explicit bias term will be applied to a representative demonstrator case based on the thermal response of the Nibelungenbrücke of Worms. The findings from this work are englobed in the initiative SPP 100+, whose main aim is the extension of the service life of structures, especially through the implementation of digital twins.
T2 - EWSHM 2024 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Digital Twins
KW - Model Bias
KW - SPP100+
KW - Bridge Monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622522
DO - https://doi.org/10.58286/30524
SN - 2941-4989
IS - 12
SP - 1
EP - 10
PB - NDT.net GmbH & Co. KG
CY - Mayen, Germany
AN - OPUS4-62252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Zaripova, Gulshat
A1 - Brinkmann, Nienke
A1 - Gebraad, Lars
A1 - Boehm, Christian
A1 - Trattnig, Horst
T1 - Simulation der Schallemissionen von Spanndrahtbrüchen
N2 - In den 1950er Jahren setzte sich die Spannbetonbauweise für Brücken mit größeren Spannweiten durch. Heute existieren im deutschen Bundesfernstraßennetz ca. 21.000 Spannbetonbrücken. Die mangelnde Erfahrung in der Anfangszeit dieser Bauweise stellt uns heute vor Probleme hinsichtlich einer Kombination aus Korrosion und Ermüdung der Spannglieder. Hauptursachen sind Spannungsrisskorrosion, deutlich gewachsene Verkehrslasten sowie ungenügende Annahmen zu Temperaturlasten. Insbesondere Spanndrahtbrüche infolge Spannungsrisskorrosion können zu einem Strukturversagen ohne Ankündigung führen. Spannstähle mit einer starken Gefährdung für Spannungsrisskorrosion wurden in der Bundesrepublik bis 1965, in der ehemaligen DDR bis Ende der 1980er Jahre verbaut. Um katastrophale Schadensfälle zu verhindern, müssen Bauwerke unter Verdacht auf Spannungsrisskorrosion in Kombination mit unzureichendem Ankündigungsverhalten überwacht werden. Derzeit ist die Schallemissionsanalyse die einzige zuverlässige und ökonomisch vertretbare Überwachungsmethode. Damit kann der sichere Betrieb der Bauwerke über die verbleibende Nutzungsdauer gewährleistet werden. Die DGZfP-Richtlinie SE05 “Detektion von Spanndrahtbrüchen mit Schallemissionsanalyse” beschreibt detailliert Planung, Installation und Betrieb solcher Monitoringsysteme. Im Projekt SimAS “Digitaler Zwilling zur Simulation der Ausbreitung akustischer Wellen in Spannbetonelementen” werden die Grundlagen für eine Optimierung der Monitoringsysteme auf Basis der Schallemissionsanalyse gelegt. Eine akustische Simulation der Struktur und deren Fusion mit Messdaten unterstützt sowohl die vorbereitenden akustischen Analysen der Brücken als auch die Planung der Monitoringsysteme und die Drahtbrucherkennung
T2 - SCHALL 25 – Schallemissionsanalyse und Zustandsüberwachung mit geführten Wellen
CY - Dresden, Germany
DA - 27.03.2025
KW - Acoustic Emission
KW - Simulation
KW - Schallemission
KW - Spannbetonbrücke
KW - Spanndrahtbruch
KW - Digitaler akustischer Zwilling
KW - Spannungsrisskorrosion
KW - Schallemissionsanalyse
KW - Schallausbreitung
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628347
DO - https://doi.org/10.58286/30964
VL - 4
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung
AN - OPUS4-62834
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Robens-Radermacher, Annika
A1 - Unger, Jörg F.
T1 - Efficient structural reliability analysis by using a PGD model in an adaptive importance sampling schema
N2 - One of the most important goals in civil engineering is to guarantee the safety of the construction. Standards prescribe a required failure probability in the order of 10−4 to 10−6. Generally, it is not possible to compute the failure probability analytically.
Therefore, many approximation methods have been developed to estimate the failure probability. Nevertheless, these methods still require a large number of evaluations of the investigated structure, usually finite element (FE) simulations, making full probabilistic design studies not feasible for relevant applications. The aim of this paper is to increase the efficiency of structural reliability analysis by means of reduced order models. The developed method paves the way for using full probabilistic approaches in industrial applications. In the proposed PGD reliability analysis, the solution of the structural computation is directly obtained from evaluating the PGD solution for a specific parameter set without computing a full FE simulation. Additionally, an adaptive importance sampling scheme is used to minimize the total number of required samples. The accuracy of the failure probability depends on the accuracy of the PGD model (mainly influenced on mesh discretization and mode truncation) as well as the number of samples in the sampling algorithm. Therefore, a general iterative PGD reliability procedure is developed to automatically verify the accuracy of the computed failure probability. It is based on a goal-oriented refinement of the PGD model around the adaptively approximated design point. The methodology is applied and evaluated for 1D and 2D examples. The computational savings compared to the method based on a FE model is shown and the influence of the accuracy of the PGD model on the failure probability is studied.
KW - Reliability
KW - Probability of failure
KW - Adaptive importance sampling
KW - Reduced order models
KW - Proper Generalized Decomposition
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510345
DO - https://doi.org/10.1186/s40323-020-00168-z
VL - 7
SP - Article number: 29
PB - SpringerOpen
AN - OPUS4-51034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
T1 - Quantification of the Knudsen Effect on the Effective Gas diffusion Coefficient in Partially Saturated Pore Distributions
N2 - The effective gas diffusion coefficient describes the process of gas diffusion in porous materials. Several materials have a significant number of micropores in the lower nanometre range leading to a reduction of gas diffusion (Knudsen effect). In the case of partial pore saturation during adsorption, the available pore space is further reduced, as is the gas diffusion. In this study, the influence of partially saturated pores on the Knudsen effect and on the gas diffusion is quantified. Three different pore geometries are investigated (slit, cylindrical and spherical pores) and three different types of pore size distribution, including a broad equal distribution, three narrow normal distributions and two measured distributions of concrete.
Besides the intensive computation of the exact pore saturation, a simplified model with low computational requirements is suggested. This study shows that the influence of the water layer thickness on the effective diffusion becomes significant for pore radii below 50 nm and the assumed pore geometry is important. At the end, the overall effect is quantified for an amorphous material with most pore
radii below 30 nm. At a moisture level of 50% relative humidity, the effective diffusion is reduced by 35% due to partial saturation.
KW - Effective gas diffusion coefficient
KW - Gas transport in porous media
KW - Knudsen diffusion
KW - Moisture transport
KW - Nanopores
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528509
DO - https://doi.org/10.1002/adem.202100106
VL - 23
IS - 10
SP - 2100106
PB - Wiley
AN - OPUS4-52850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klewe, Tim
A1 - Strangfeld, Christoph
A1 - Ritzer, Tobias
A1 - Kruschwitz, Sabine
T1 - Classification of Practical Floor Moisture Damage Using GPR - Limits and Opportunities
N2 - Machine learning in non-destructive testing (NDT) offers significant potential for efficient daily data analysis and uncovering previously unknown relationships in persistent problems. However, its successful application heavily depends on the availability of a diverse and well-labeled training dataset, which is often lacking, raising questions about the transferability of trained algorithms to new datasets. To examine this issue closely, the authors applied classifiers trained with laboratory Ground Penetrating Radar (GPR) data to categorize on-site moisture damage in layered building floors. The investigations were conducted at five different locations in Germany. For reference, cores were taken at each measurement point and labeled as (i) dry, (ii) with insulation damage, or (iii) with screed damage. Compared to the accuracies of 84 % to 90 % within the laboratory training data (504 B-Scans), the classifiers achieved a lower overall accuracy of 53 % for on-site data (72 B-Scans). This discrepancy is mainly attributable to a significantly higher dynamic of all signal features extracted from on-site measurements compared to laboratory training data. Nevertheless, this study highlights the promising sensitivity of GPR for identifying individual damage cases. In particular the results showing insulation damage, which cannot be detected by any other non-destructive method, revealed characteristic patterns. The accurate interpretation of such results still depends on trained personnel, whereby fully automated approaches would require a larger and diverse on-site data set. Until then, the findings of this work contribute to a more reliable analysis of moisture damage in building floors using GPR and offer practical insights into applying machine learning to non-destructive testing for civil engineering (NDT-CE).
KW - GPR
KW - Material moisture
KW - Building floor
KW - Machine Learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607932
DO - https://doi.org/10.1007/s10921-024-01111-7
SN - 0195-9298
VL - 43
IS - 3
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-60793
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönsee, Eric
A1 - Jeyifous, Olubunmi Anthony
A1 - Strangfeld, Christoph
A1 - Hüsken, Götz
T1 - Investigations on multi-sensor data for monitoring volume flow during the printing process
N2 - Extrusion based 3D concrete printing (3DCP) is a growing technology because of its high potential for automating construction and the new possibilities of design. In conventional construction methods, a sample is taken to be representative for one material batch. However, in 3DCP continuous mixing is used which results in variations during the mixing process. Therefore, one sample is not representative for the entire structure. This leads to the necessity of continuous and real-time process monitoring.
This study focuses on the variations of pressure and temperature which are caused by changes in the material due to the ongoing mixing process. Changes in material, which is transported downstream, are influencing sensor signals in different positions with a time delay. In the following, the data is analysed to investigate if the changing material and the so caused change in pressure can be used to calculate volume flow.
T2 - Digital Concrete 2024
CY - Munich, Germany
DA - 04.09.2024
KW - Additive manufacturing
KW - In-line Monitoring
KW - Volume Flow
KW - Process Control
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:gbv:084-2024081513042
DO - https://doi.org/10.24355/dbbs.084-202408151304-0
SP - 1
EP - 3
AN - OPUS4-61001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munsch, Sarah Mandy
A1 - Strangfeld, Christoph
A1 - Kruschwitz, Sabine
T1 - Application of 1H proton NMR relaxometry to building materials - A review
N2 - Since nuclear magnetic resonance with focus on 1H protons is highly sensitive to pore filling fluids, it is nowadays often applied for the investigation of porous media. Mainly in materials research and especially in the field of non-destructive testing in civil engineering it is increasingly used. Scientific questions about and based on NMR meanwhile cover a broad spectrum. To give an overview, we have reviewed various studies dealing with the determination of moisture contents and parameters such as the pore-size distribution, surface relaxivity, porosity, etc. In some papers, the monitoring of moisture transport in connection with degradation processes or admixtures was the main objective. In other papers, NMR was used for pore space analysis or even applied on site to assess the state of conservation of cultural heritage. Building materials that have been investigated in the presented studies are for example cement, concrete, woods, sandstones etc. In this paper, short descriptions and the significant results of the reviewed articles are summarized and their measurement problems and discrepancies are pointed out. A special feature of this review article is the concise tabular compilation of determined 𝑇1 and 𝑇2 relaxation times, as well as of surface relaxivity values for various materials and components. Finally, relevant aspects are summed up and conclusions about the increasing potential of NMR relaxometry for investigations of porous building materials are drawn, followed by an outlook about future applications and the need for technical development.
KW - NMR relaxometry
KW - Building materials
KW - Natural stones
KW - Relaxation times
KW - Surface relaxivities
KW - Moisture
KW - Pore space characterization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521888
DO - https://doi.org/10.1016/j.jmro.2021.100012
N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M.
VL - 6-7
SP - 100012
PB - Elsevier Inc.
CY - Amsterdam
AN - OPUS4-52188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Küttenbaum, Stefan
A1 - Maack, Stefan
A1 - Braml, T.
A1 - Taffe, A.
A1 - Strübing, T.
T1 - Bewertung von Bestandsbauwerken mit gemessenen Daten - Teil 2: Berechnung der Tragwerkszuverlässigkeit unter Einbeziehung der ZfP-Messergebnisse
T1 - Reassessment of existing structures based on measured data - Part 2: Structural reliability analyses using NDT results
N2 - Durch die Einbeziehung von gemessenen Daten bei der Bewertung von bestehenden Bauwerken können Unsicherheiten bei der Beurteilung des Tragverhaltens reduziert werden, ohne das normative Zuverlässigkeitsniveau einzuschränken. Informationen sind die wesentliche Grundlage für die Analyse der Zuverlässigkeit von Tragwerken. Umso wichtiger ist die Kenntnis über die Präzision und die Richtigkeit der verwendeten Informationen. Aus messtechnischer Sicht kann ein Messwert, dem keine Messunsicherheit beigeordnet wurde, als wertlos erachtet werden. Liegt ein vollständig dokumentiertes Messergebnis vor, so ist die Qualität der gemessenen Information bekannt und deren Vergleichbarkeit gewährleistet. In diesem Beitrag wird am Beispiel einer Spannbetonbrücke und zweier Grenzzustände gezeigt, wie Messergebnisse aus der zerstörungsfreien Prüfung in probabilistische Nachweise von Bestandsbauwerken einfließen können und welche Auswirkungen die Implementierung von gemessenen Daten bei der Bewertung von Bestandsbauwerken haben kann.
N2 - Every decision about the reliability of a structure is associated with uncertainties. The reassessment of existing structures remains a major challenge. The decisive difference compared to the design of new structures is the possibility and necessity to collect individual information about the actual condition and properties of the structure. Such knowledge should be appreciated in the reassessment in order to reduce uncertainties and increase the validity of the results. Reliability analyses using measured data require the comparability of measurement results and the evaluation of the quality of the measured information. Both requirements can be met by adequate measurement uncertainty considerations. Besides, the destructive interventions necessary for the measurements should be kept to a minimum. This paper shows how non-destructively gathered measurement results can be incorporated into probabilistic reassessments and which effects the implementation of measured data can have when evaluating existing structures, using a prestressed concrete bridge as a case-study.
KW - Nachrechnung
KW - Zerstörungsfreie Prüfung
KW - Zuverlässigkeitsanalyse
KW - Messung
KW - Spannbetonbrücke
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519480
DO - https://doi.org/10.1002/best.202000087
SN - 0005-9900
SN - 1437-1006
VL - 116
IS - 3
SP - 183
EP - 199
PB - Ernst & Sohn
CY - Berlin
AN - OPUS4-51948
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Werder, Julia
A1 - Simon, Sebastian
A1 - Gardei, André
A1 - Fontana, P.
A1 - Meng, Birgit
T1 - Thermal and hydrothermal treatment of UHPC: influence of the process parameters on the phase composition of ultra-high performance concrete
N2 - Several studies show that thermal and hydrothermal treatment can further improve the excellent properties of UHPC in terms of mechanical strength and durability. While for the thermal treatment the increase in strength is attributed to an intensified pozzolanic and hydraulic reaction, for the hydrothermal treatment previous studies accredited it mostly to the formation of tobermorite. In the presented study thermal and hydrothermal treatment of UHPC samples was systematically varied and the phase formation analysed related to the strength development of a reference sample cured for 28 days in water. For the thermal treatment the results show that the strength increase depends on the protection against desiccation and can be ascribed to an improved pozzolanic reaction of the siliceous fillers. To achieve a significant enhancement of strength, a pre-storage time of few days and a long dwell time at elevated temperature/pressure are required. For the hydrothermal treatment already heating the specimens up to 185 °C in saturated steam followed by an immediate cooling leads to a substantial increase in compressive strength. Pre-storage time did not affect the result as far as a minimum of several hours is guaranteed. The improved performance is due to an increase in the pozzolanic and hydraulic reaction. Surprisingly, tobermorite was only found within a very thin layer at the surface of the sample, but not in the bulk. Sulphate and aluminium stemming from the decomposition of the ettringite are bound in the newly formed phases hydroxylellestadite and hydrogarnet.
KW - UHPC
KW - Thermal treatment
KW - Hydrothermal treatment
KW - Compressive strength
KW - Phase development
KW - Durability
KW - Tobermorite
KW - Hydroxylellestadite
KW - Hydrogarnet
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523402
DO - https://doi.org/10.1617/s11527-021-01633-w
SN - 1871-6873
SN - 1359-5997
VL - 54
IS - 1
SP - Article 44
PB - Springer Nature
AN - OPUS4-52340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Strangfeld, Christoph
A1 - Maack, Stefan
A1 - Schweitzer, T.
T1 - Experimental analysis of the acoustic field of an ultrasonic pulse induced by a fluidic switch
N2 - Ultrasonic inspection is a common tool for non-destructive testing in civil engineering (NDT-CE). Currently, transducers are coupled directly to the specimen surface, which makes the inspection time-consuming. Air-coupled ultrasound (ACU) transducers are more time-efficient but need a high pressure amplitude as the impedance mismatch between the air and the concrete is high and large penetration depth is needed for the inspection. Current approaches aim at eliminating the impedance mismatch between the transducer and the air to gain amplitude; however, they hardly fulfill the NDT-CE requirements. In this study, an alternative approach for ultrasound generation is presented: the signal is generated by a fluidic switch that rapidly injects a mass flow into the ambience. The acoustic field, the flow field, and their interaction are investigated. It is shown that the signal has dominant frequencies in the range of 35–60 kHz, and the amplitude is comparable to that of a commercial ACU transducer.
KW - Air-coupled ultrasound
KW - Non-destructive testing
KW - Ultrasonic transducer
KW - Acoustic-flow interaction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523862
DO - https://doi.org/10.1121/10.0003937
VL - 149
IS - 4
SP - 2150
EP - 2158
AN - OPUS4-52386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Viefhues, Eva
A1 - Döhler, M.
A1 - Hille, Falk
A1 - Mevel, L.
T1 - Fault detection for linear parameter varying systems under changes in the process noise covariance
N2 - Detecting changes in the eigenstructure of linear systems is a comprehensively investigated subject. In particular, change detection methods based on hypothesis testing using Gaussian residuals have been developed previously. In such residuals, a reference model is confronted to data from the current system. In this paper, linear output-only systems depending on a varying external physical parameter are considered. These systems are driven by process noise, whose covariance may also vary between measurements. To deal with the varying parameter, an interpolation approach is pursued, where a limited number of reference models – each estimated from data measured in a reference state – are interpolated to approximate an adequate reference model for the current parameter. The problem becomes more complex when the different points of interpolation correspond to different noise conditions. Then conflicts may arise between the detection of changes in the eigenstructure due to a fault and the detection of changes due to different noise conditions. For this case, a new change detection approach is developed based on the interpolation of the eigenstructure at the reference points. The resulting approach is capable of change detection when both the external physical parameter and the process noise conditions are varying. This approach is validated on a numerical simulation of a mechanical system.
T2 - 21st IFAC World Congress
CY - Online meeting
DA - 13.07.2020
KW - Linear parameter varying systems
KW - Fault detectionchanging
KW - Process noise
KW - Subspace-based residual
KW - Model interpolation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524652
DO - https://doi.org/10.1016/j.ifacol.2020.12.868
SN - 2405-8963
VL - 53
IS - 2
SP - 13668
EP - 13673
PB - Elsevier
AN - OPUS4-52465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallau, Wilma
A1 - Recknagel, Christoph
T1 - Durability Assessment of Structural Sealant Glazing Systems applying a Performance Test Method
N2 - During the service life of a Structural Sealant Glazing (SSG) facade, its silicone bond is exposed to climatic, chemical, and mechanical loads. While current durability assessment methods schedule separate test programmes for accelerated weathering and fatigue, the presented test applies mechanical loading and weather cycling simultaneously to simulate 50 years of use. Specifically designed medium-scale system specimens resemble a common SSG-bond. Displacement-controlled sinusoidal load cycles in two load directions subject these specimens to tensile, compression and shear loads. Weathering comprises temperature and humidity cycles, UV-radiation, and application of water and detergent. During testing, the forces transmitted by the system specimens are continuously measured for performance assessment. The resulting system response reveals mechanical performance characteristics like elastic moduli and dissipated energies which decrease during exposure, indicating stress relaxation and degradation. Two common structural sealants were tested. After testing, sections of the system specimens were subjected to tensile and shear tests for mechanical characterisation. Strengths and moduli are notably reduced by combined loading compared to those of reference and weathered specimens. Hardness and visual inspections of the bond correlate with the performance and bond characteristics. The approach introduced in this article provides a basis for life cycle assessment of SSG-systems.
KW - Structural sealant glazing
KW - Cyclic weathering
KW - Mechanical loading
KW - Artificial ageing
KW - Durability assessment
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519172
DO - https://doi.org/10.1080/00218464.2020.1840985
VL - 98
IS - 5
SP - 464
EP - 487
PB - Taylor & Francis Group
AN - OPUS4-51917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, D.
A1 - Schmitt, M.
A1 - Maack, Stefan
A1 - Baensch, F.
T1 - Erarbeitung einer Norm für einen standardisierten Prozess zur probabilistischen Bewertung von Prüfverfahren
N2 - Im DIN-Normenausschuss Materialprüfung (NMP) wurde das Normungsgremium NA 062-08-28 AA „Qualifizierung von zerstörungsfreien Prüfungen“ reaktiviert. Das Ziel der Reaktivierung ist die Erarbeitung einer Norm für einen standardisierten Prozess zur probabilistischen Bewertung von Prüfverfahren.
In der zerstörungsfreien Prüfung (ZfP) führt die Ermittlung von Mess- / Prüfunsicherheiten von Prüfverfahren, in normativer Hinsicht in Deutschland und Europa, noch ein Schattendasein. Die Norm ISO IEC 17025 und auch der VDA-Band 5 wurden weiter in Richtung Messunsicherheit entwickelt, allerdings führt ihre Anwendung in der ZfP zu Problemen.
Der Arbeitsausschuss NA 062-08-28 AA soll hier den Brückenschlag zwischen Messunsicherheit, objektiver statistischer Bewertung für ZfP-Verfahren und eine weitere Stärkung der probabilistischen Bruchmechanik erreichen. Geplant ist daher die Erarbeitung einer DIN-Norm, welche die Kriterien für eine korrekte Versuchsplanung, ein praktikables Vorgehen zur Bewertung der Prüfergebnisse und die mathematische Überführung in eine Zuverlässigkeitsaussage enthält. Es soll ein Leitfaden erstellt werden, der für ein möglichst breites Branchenspektrum eingesetzt werden kann, unabhängig von den Besonderheiten verschiedener Industriezweige.
Dargestellt werden das relevante Normungsgremium sowie der Hintergrund des zu erstellenden Dokuments.
T2 - DGZfP Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Validation
KW - Probabilistischen Bewertung
KW - Zerstörungsfreie Prüfverfahren
KW - POD
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584176
UR - https://www.ndt.net/search/docs.php3?id=28574
SN - 978-3-947971-29-9
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-58417
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Küttenbaum, Stefan
A1 - Braml, T.
A1 - Heinze, M.
A1 - Kainz, C.
A1 - Keuser, M.
A1 - Kotz, P.
A1 - Lechner, T.
A1 - Maack, Stefan
A1 - Reinke, K.-D.
A1 - Schulze, S.
A1 - Soukup, A.
A1 - Stettner, C.
A1 - Taffe, A.
A1 - Wöstmann, Jens
T1 - Guideline on NDT-supported reliability assessment of existing structures - Current developments in Germany
N2 - Information about an existing structure can be collected at certain costs to evaluate the reliability and condition as realistically as necessary. This information can be relevant or irrelevant, true or biased, precise or imprecise. The incorporation of relevant and quality-assessed measured information into reliability reassessment offers the chance to extend remaining lifetimes and support decision making about optimal actions or maintenance strategies. This paper shows recent developments in a national research project that aims to produce a guideline on the NDT-based, structure-specific modification of partial safety factors. The general methodology, results from recalculations according to the Eurocodes and metrologically solvable testing tasks relevant in the recalculation of the concrete bridges are shown and compared with the non-destructive testing methods applicable to concrete bridges. A case study is used to demonstrate that as-built drawings, in this case of the positions of tendons and shear reinforcement, can be verified using the radar method.
KW - Non-destructive testing
KW - Concrete bridges
KW - Partial safety factor modification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584862
DO - https://doi.org/10.1002/cepa.2168
SN - 2509-7075
VL - 6
IS - 5
SP - 537
EP - 543
PB - Ernst & Sohn
CY - Berlin
AN - OPUS4-58486
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Küttenbaum, Stefan
A1 - Braml, T.
A1 - Taffe, A.
A1 - Maack, Stefan
ED - Li, J.
ED - Spanos, D.
ED - Chen, J. B.
ED - Peng, Y. B.
T1 - Towards NDT-supported decisions on the reliability of existing bridges
N2 - A major advantage in the reassessment of existing structures is the possibility of including measured data that describe the actual properties and the current condition of the structure to be reassessed. Currently, the incorporation of such measured information is mostly unregulated. However, the use of measurement results is vitally important, since a measured data-based improvement of the computation models level of approximation can lead at least to more meaningful results, possibly to extended remaining life times of the structure and in the best case to a saving of resources. Conversely, not appreciating well measurable and relevant information can be equated with a waste of resources. In this paper, a concept for the comparable use of non-destructively measured data as basic variables in probabilistic reliability assessments is outlined and examined using a typical prestressed concrete road bridge as a case-study. An essential requirement is the calculation of measurement uncertainties in order to evaluate the quality of the measurement results comparably. In conclusion, the example of ultrasonic and radar measurement data is used to demonstrate the effects that the incorporation of the measured information has on the reliability of the structure.
T2 - 13th International Conference on Structural Safety and Reliability (ICOSSAR 2021-2022)
CY - Online meeting
DA - 13.09.2022
KW - Measurement uncertainty
KW - Reliability assessment
KW - Existing structures
KW - Concrete Bridge
KW - Non-Destructive Testing (NDT)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583013
SP - 1
EP - 10
AN - OPUS4-58301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andrés Arcones, Daniel
A1 - Weiser, M.
A1 - Koutsourelakis, F.
A1 - Unger, Jörg F.
T1 - A Bayesian Framework for Simulation-based Digital Twins of Bridges
N2 - Simulation-based digital twins have emerged as a powerful tool for evaluating the mechanical response of bridges. As virtual representations of physical systems, digital twins can provide a wealth of information that complements traditional inspection and monitoring data. By incorporating virtual sensors and predictive maintenance strategies, they have the potential to improve our understanding of the behavior and performance of bridges over time. However, as bridges age and undergo regular loading and extreme events, their tructural characteristics change, often differing from the predictions of their initial design. Digital twins must be continuously adapted to reflect these changes. In this article, we present a Bayesian framework for updating simulation-based digital twins in the context of bridges. Our approach integrates information from measurements to account for inaccuracies in the simulation model and quantify uncertainties. Through its implementation and assessment, this work demonstrates the potential for digital twins to provide a reliable and up-to-date representation of bridge behavior, helping to inform decision-making for maintenance and management.
T2 - Eurostruct 2023
CY - Vienna, Austria
DA - 25.09.2023
KW - Digital Twins
KW - Bayesian Inference
KW - Bridge Monitoring
KW - Uncertainty Quantification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586803
UR - https://eurostruct.org/eurostruct-2023/
DO - https://doi.org/10.1002/cepa.2177
SN - 2509-7075
VL - 6
IS - 5
SP - 734
EP - 740
PB - Ernst & Sohn
CY - Berlin
AN - OPUS4-58680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
A1 - Bintz, Thilo
A1 - Heyn, R.
A1 - Hirsch, H.
A1 - Grunewald, J.
A1 - Kruschwitz, Sabine
T1 - Detailed investigation of capillary active insulation materials by 1H nuclear magnetic resonance (NMR) and thermogravimetric drying
N2 - Capillary active interior insulation materials are an important approach to minimize energy losses of historical buildings. A key factor for their performance is a high liquid conductivity, which enables redistribution of liquid moisture within the material. We set up an experiment to investigate the development of moisture profiles within two different interior insulation materials, calcium-silicate (CaSi) and expanded perlite (EP), under constant boundary conditions. The moisture profiles were determined by two different methods: simple destructive sample slicing with subsequent thermogravimetric drying as well as non-destructive NMR measurements with high spatial resolution. The moisture profiles obtained from both methods show good agreement, when compared at the low spatial resolution of sample slicing, which demonstrates the reliability of this method. Moreover, the measured T2-relaxation-time distributions across the sample depth were measured, which may give further insight into the saturation degree of the different pore sizes. In order to explain differences in the moisture profiles between CaSi and EP, we determined their pore-size distribution with different methods: conversion of the NMR T2 relaxationtime distribution at full saturation, mercury intrusion porosimetry and indirect determination from pressure plate measurements. CaSi shows a unimodal distribution at small pore diameters, while in EP, a bi-modal or wider distribution was found. We assume that the smaller pore diameters of CaSi lead to a higher capillary conductivity, which causes a more distributed moisture profile in comparison with that of EP.
T2 - NDT-CE
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Insulation material
KW - Nuclear magnetic resonance
KW - Capillary conductivity
KW - Pore-size distribution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579172
DO - https://doi.org/10.58286/27205
SN - 1435-4934
VL - 27
IS - 9
SP - 1
EP - 11
AN - OPUS4-57917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallau, Wilma
A1 - Pirskawetz, Stephan
A1 - Voland, K.
A1 - Meng, Birgit
T1 - Continuous expansion measurement in accelerated concrete prism testing for verifying ASR-expansion models
N2 - The susceptibility of concrete structures due to alkali–silica reaction (ASR) can be assessed by means of ASR concrete prism testing at 60 °C, according to RILEM AAR 4.1. There, expansion of concrete prisms indicates alkali-reactivity of the examined concrete mix. This work applies in situ expansion measurement to accelerated concrete prism testing. Automated measuring facilitates both storage without the usually necessary interruptions for manual measurement and acquisition of quasi-continuousexpansion data. A comparative experimental programme showed that conventional testing resulted in stronger expansion and leaching of alkalis than automated testing. Experimental simulation of interruptions, typically associated with manual measurements in conventional testing, could prove the influence of these cooling–heating cycles. Two phenomenological approaches, frequently used for describing reaction kinetics of ASR by linking it to expansion results from ASR-testing, were validated with continuous expansion data of three types of aggregate. Experimental expansion depicted s-shaped curves similar to them of the modelling approaches. However, strong swelling recorded in the beginning of the test was not covered by the model curves. Auxiliary measurement of acoustic emissions and ultrasonic velocity helped characterising mechanisms such as hydration and cracking, which also influence prism expansion. The proposed modification of the measurement procedure provides an extended basis to analyse expansion mechanisms. Regarding data for validation of ASR-expansion models, continuous expansion results are preferable to conventional test results.
KW - Alkali–silica reaction
KW - Accelerated concrete prism test
KW - Automated expansion measurement
KW - ASR modelling
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-455959
DO - https://doi.org/10.1617/s11527-018-1205-0
SN - 1359-5997
SN - 1871-6873
VL - 51
IS - 3
SP - 51
EP - 79
PB - Springer
AN - OPUS4-45595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Küttenbaum, Stefan
A1 - Taffe, A.
A1 - Braml, T.
A1 - Maack, Stefan
ED - Alexander, M. G.
ED - Beushausen, H.
ED - Dehn, F.
ED - Moyo, P.
T1 - Reliability assessment of existing bridge constructions based on results of non-destructive testing
N2 - The non-destructive testing methods available for civil engineering (NDT-CE) enable the measurements of quantitative parameters, which realistically describe the characteristics of existing buildings. In the past, methods for quality evaluation and concepts for validation expanded into NDT-CE to improve the objectivity of measured data. Thereby, a metrological foundation was developed to collect statistically sound and structurally relevant information about the inner construction of structures without destructive interventions. More recently, the demand for recalculations of structural safety was identified. This paper summarizes a basic research study on structural analyses of bridges in combination with NDT. The aim is to use measurement data of nondestructive testing methods as stochastic quantities in static calculations. Therefore, a methodical interface between the guide to the expression of uncertainty in measurement and probabilistic approximation procedures (e.g. FORM) has been proven to be suitable. The motivation is to relate the scientific approach of the structural analysis with real information coming from existing structures and not with those found in the literature. A case study about the probabilistic bending proof of a reinforced concrete bridge with statistically verified data from ultrasonic measurements shows that the measuring results fulfil the requirements concerning precision, trueness, objectivity and reliability.
T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018)
CY - Cape Town, South Africa
DA - 19.11.2018
KW - NDT
KW - Concrete
KW - Probabilistic reassessment
KW - Bridge
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467898
DO - https://doi.org/10.1051/matecconf/201819906001
SN - 2261-236X
VL - 199
SP - 06001, 1
EP - 9
PB - MATEC Web of Conferences
AN - OPUS4-46789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Makris, Ruben
A1 - Hille, Falk
A1 - Thiele, Marc
A1 - Kirschberger, D.
A1 - Sowietzki, D.
T1 - Crack luminescence as an innovative method for detection of fatigue damage
N2 - In structural parts under vibrational loading fatigue cracks can initiate and grow, which can lead to structural failure. Conventional non-destructive testing methods for crack detection provide just a snapshot of fatigue crack evolution, whereas crack luminescence coating realizes clear visibility of the entire crack formation. Fatigue causing cyclic tensile tests and examinations on special test bodies allowing control of the crack opening width demonstrate a high sensitivity of the coating.
KW - Fatigue damage
KW - Crack
KW - Luminescence
KW - Detection
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446693
DO - https://doi.org/10.5194/jsss-7-259-2018
SN - 2194-8771
SN - 2194-878X
VL - 7
SP - 259
EP - 266
PB - Copernicus Publications
CY - Göttingen, Germany
AN - OPUS4-44669
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maack, Stefan
A1 - Villalobos, S.
A1 - Scott, D.
T1 - Validation of artificial defects for non-destructive testing measurements on a reference structure
N2 - Non-destructive testing was established over the last decades as an important tool for assessing damages, material characterization and quality assurance in civil engineering. For example, Ground Penetrating Radar (GPR) can be used to scan large areas of concrete structures to determine the spatial position of the reinforcement. With the ultrasonic echo method, the thickness of concrete structures can be easily determined even if a high density of reinforcement is given. Various methods and processes have been developed for the validation of NDT procedures aiming at ensuring the quality of measurements in practical use. The Probability of Detection (POD) for example, is an available method to compare different technical devices with each other quantitatively regarding their performance. With this method, the best suited testing device for a specific inspection task under defined boundary conditions can be selected. By using the Guide to the Expression of Uncertainty in Measurement (GUM), it is possible to quantify the measurement uncertainty of an inspection procedure for a specific task. Another important aspect to improve the acceptance of Non-destructive testing methods is the development of reference specimens.
Reference specimens serve for the calibration and further development of NDT methods under realistic conditions in different laboratories under the same conditions. A particular challenge here is the most realistic representation of a damage that can occur at building sites. Possible damages include for example horizontal and vertical cracks or honeycombs in concrete. Such a reference structure was built for the development of a new design of power plant constructions. Comparative studies on the manufacturing of realistic honeycombs and delaminations were carried out in advance on a test specimen. The results of this study are presented here.
T2 - ICCRRR 2018 - Concrete Repair, Rehabilitation and Retrofitting
CY - Cape Town, South Africa
DA - 19.11.2018
KW - Zerstörungsfreie Prüfung
KW - Nondestructive testing
KW - Istzustandserfassung
KW - Ultrasonic
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464497
DO - https://doi.org/10.1051/matecconf/201819906006
SN - 2261-236X
VL - 199
SP - 1
EP - 9
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-46449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Taffe, A.
A1 - Küttenbaum, Stefan
A1 - Maack, Stefan
T1 - ZfPStatik - Messergebnisse rechenbar machen
N2 - ZfPStatik bezeichnet die Verwendung von statistisch bewerteten Messergebnissen, die mit zerstörungsfreien Prüfverfahren im Bauwesen (ZfPBau) gewonnen werden und in statischen Berechnungen zum Nachweis der Tragfähigkeit verwendet werden. Dazu ist die Ermittlung der Messunsicherheit der Versuchsdaten auf der Basis des GUM (Guide to the Expression of Uncertainty in Measurement) der erste Schritt. Der statische Nachweis erfolgt durch Grenzzustandsgleichungen, die im Bauwesen angewandt werden. Diese müssen modifiziert werden, so dass jede Messgröße als Zufallsvariable in der Grenzzustandsgleichung vorhanden ist. Der statische Nachweis erfolgt mit probabilistischen Berechnungsmethoden aus der Zuverlässigkeitstheorie. Diese Vorgehensweise wird exemplarisch für den Standsicherheitsnachweis eines Plattenbalkenquerschnitts einer Stahlbetonbrücke auf Biegung angewandt. Auf die möglichen Schlussfolgerungen aus den probabilistischen Berechnungen wird abschließend kurz eingegangen.
T2 - DGZfP-Fachtagung Bauwerksdiagnose 2018
CY - Berlin, Germany
DA - 15.02.2018
KW - ZfP
KW - ZfPBau
KW - ZfPStatik
KW - Zuverlässigkeitstheorie
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-442266
UR - https://www.bauwerksdiagnose2018.de/Portals/bauwerksdiagnose2018/BB/20.pdf
UR - https://www.bauwerksdiagnose2018.de
SN - 978-3-940283-90-0
VL - BB 165
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-44226
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bartels, Jan-Hauke
A1 - Xu, Ronghua
A1 - Kang, Chongjie
A1 - Herrmann, Ralf
A1 - Marx, Steffen
T1 - Experimental Investigation on the Transfer Behavior and Environmental Influences of Low-Noise Integrated Electronic Piezoelectric Acceleration Sensors
N2 - Acceleration sensors are vital for assessing engineering structures by measuring properties like natural frequencies. In practice, engineering structures often have low natural frequencies and face harsh environmental conditions. Understanding sensor behavior on such structures is crucial for reliable masurements. The research focus is on understanding the behavior of acceleration sensors in harsh environmental conditions within the low-frequency acceleration range. The main question is how to distinguish sensor behavior from structural influences to minimize errors in assessing engineering structure conditions. To investigate this, the sensors are tested using a long-stroke calibration unit under varying temperature and humidity conditions. Additionally, a mini-monitoring system configured with four IEPE sensors is applied to a small-scale support structure within a climate chamber. For the evaluation, a signal-energy approach is employed to distinguish sensor behavior from structural behavior. The findings show that IEPE sensors display temperature-dependent nonlinear transmission behavior within the low-frequency acceleration range, with humidity having negligible impact. To ensure accurate engineering structure assessment, it is crucial to separate sensor behavior from structural influences using signal energy in the time domain. This study underscores the need to compensate for systematic effects, preventing the underestimation of vibration energy at low temperatures and overestimation at higher temperatures when using IEPE sensors for engineering structure monitoring.
KW - Acceleration sensors
KW - Environmental influence
KW - IEPE
KW - Structural Health Monitoring
KW - Low-frequency shaker
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594623
UR - https://www.mdpi.com/2673-8244/4/1/4/
DO - https://doi.org/10.3390/metrology4010004
SN - 2673-8244
VL - 4
IS - 1
SP - 46
EP - 65
PB - MDPI
CY - Basel
AN - OPUS4-59462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klimek, André
A1 - Stelzner, Ludwig
A1 - Hothan, Sascha
A1 - Zehfuß, Jochen
T1 - Influence of thermal strain on concrete spalling
N2 - Understanding the susceptibility to spalling of concrete members in case of fire is important to evaluate the residual load-bearing capacity. The investigations of the spalling phenomenon of a concrete mixture using real scale members are necessary but expensive to carry out. Reducing the specimen size leads to an increase of boundary effects that can result in a reduced spalling or absence of spalling. In this study, fire tests were carried out on unrestrained, single-sided exposed, cuboid shaped specimens (0.6 m x 0.6 m x 0.29 m) as well as unrestrained and steel ring restrained cylindrical specimens (Ø = 0.47 m, h = 0.29 m), which induce different boundary conditions. These fire tests were carried out on two ordinary concrete mixtures. The two mixtures differ only in the type of aggregates (quartz gravel and basalt grit) and were used to investigate the influence of the thermal expansion of the aggregate on the spalling behaviour of the concrete. The results show a significant increase of
the spalling depth due to the restrained thermal expansion achieved by the applied steel rings. Additionally, the type of aggregate has a direct influence on the spalling behaviour of a concrete mixture. The reduction of the boundary effects by the steel rings recreate the test conditions in the centre of a large concrete member. Thus, this type of specimen is suitable to determine the susceptibility to spalling of a material (screening-tests) as preliminary investigations to full scale fire tests.
KW - Spalling
KW - Concrete
KW - Fire test
KW - Restraint
KW - Screening test
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593350
DO - https://doi.org/10.1617/s11527-023-02274-x
VL - 57
SP - 1
EP - 14
PB - Springer
AN - OPUS4-59335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glienke, R.
A1 - Kalkowsky, F.
A1 - Hobbacher, A. F.
A1 - Holch, A.
A1 - Thiele, Marc
A1 - Marten, F.
A1 - Kersten, R.
A1 - Henkel, K.-M.
T1 - Evaluation of the fatigue resistance of butt‑welded joints in towers of wind turbines - A comparison of experimental studies with small scale and component tests as well as numerical based approaches with local concepts
N2 - Wind turbines are exposed to a high number of load cycles during their service lifetime. Therefore, the fatigue strength verification plays an important role in their design. In general, the nominal stress method is used for the fatigue verification of the most common used butt-welded joints. The Eurocode 3 part 1–9 is the current design standard for this field of application. This paper presents recent results of fatigue tests on small-scaled specimens and large components with transverse butt welds to discuss the validity of the FAT-class. Furthermore, results from numerical simulations for the verification with the effective notch stress and the crack propagation approach are used for comparison. Based on the consistency between the numerical results and the fatigue tests, the influence of the seam geometry on the fatigue resistance was investigated. Finally, a prediction of the fatigue strength of butt-welded joints with plate thicknesses up to 80 mm was carried out.
KW - Transverse butt weld
KW - Weld imperfections
KW - Wind turbine tower
KW - Fatigue strength
KW - Local approaches
KW - Large components
KW - Wind energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596648
DO - https://doi.org/10.1007/s40194-023-01630-3
SN - 1878-6669
SP - 1
EP - 26
PB - Springer
CY - Berlin
AN - OPUS4-59664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Maack, Stefan
A1 - Strangfeld, Christoph
T1 - Fluidic Ultrasound Generation for Non‐Destructive Testing
N2 - AbstractAir‐coupled ultrasonic testing (ACU) is a pioneering technique in non‐destructive testing (NDT). While contact testing and fluid immersion testing are standard methods in many applications, the adoption of ACU is progressing slowly, especially in the low ultrasonic frequency range. A main reason for this development is the difficulty of generating high amplitude ultrasonic bursts with equipment that is robust enough to be applied outside a laboratory environment. This paper presents the fluidic ultrasonic transducer as a solution to this challenge. This novel aeroacoustic source uses the flow instability of a sonic jet in a bistable fluidic switch to generate ultrasonic bursts up to 60 kHz with a mean peak pressure of 320 Pa. The robust design allows operation in adverse environments, independent of the operating fluid. Non‐contact through‐transmission experiments are conducted on four materials and compared with the results of conventional transducers. For the first time, it is shown that the novel fluidic ultrasonic transducer provides a suitable acoustic signal for NDT tasks and has potential of furthering the implementation of ACU in industrial applications.This article is protected by copyright. All rights reserved
KW - Aeroacoustics
KW - Air-coupled ultrasound
KW - Fluidics
KW - Harsh environment
KW - Laser Doppler vibrometer
KW - Non-destructive testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594273
DO - https://doi.org/10.1002/adma.202311724
SN - 0935-9648
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-59427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hirsch, T.
A1 - Voigt, Marieke
A1 - Lehmann, Christian
A1 - Meng, Birgit
A1 - Lothenbach, B.
T1 - Impact of autoclaving on the phase assemblage of Portland cement: Experiment and thermodynamic modelling
N2 - Even after autoclaving for 2 weeks in the temperature range of 120 to 200 °C, CEM I paste with a water-to-cement ratio of 0.5 still contains some low-crystalline C-S-H. The conversion of low-crystalline C-S-H to crystalline is faster with increasing temperature. The observed low-crystalline and crystalline C-S-H phases (reinhardbraunsite, jaffeite) indicate that the sampleshave not reached equilibrium yet under these experimental conditions. However, there is a good agreement between experiment and thermodynamic modelling for the other solids indicating that the used datasets are suitable for this application.
T2 - 16th International Congress on the Chemistry of cement 2023 - ICCC2023
CY - Bangkok, Thailand
DA - 18.09.2023
KW - Zement
KW - Thermodynamik
KW - Phasenzusammensetzung
KW - Mineralogie
KW - Modellierung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589779
UR - https://iccc2023.org
VL - 1
SP - 619
EP - 621
AN - OPUS4-58977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wedel, F.
A1 - Pitters, S.
A1 - Herrmann, Ralf
A1 - Schneider, Ronald
A1 - Hille, Falk
A1 - Hindersmann, I.
T1 - Guideline for the strategic application of monitoring of road bridges in Germany
N2 - Engineering structures are an important part of our transport infrastructure. Their failure is associated with high safety risks and economic damage. Ensuring the availability of these constructions and guaranteeing their operational safety are thus important tasks. Currently, maintenance of engineering structures is a reactive process and therefore not yet a predictive process. Every 3 to 6 years, the structures are visually inspected, all damages are documented and a condition grade is assigned to the structure based on the detected damages. Continuous data-providing methods such as monitoring are used only very occasionally. With the help of monitoring, condition data about the structures are continuously collected, which can be used for a better assessment of the structures. On the one hand, this would increase safety of engineering structures, and on the other hand, it makes the shift towards predictive maintenance management based on real-time data and predictions, where the onset of damage is detected before it occurs, possible in the first place. Monitoring plays therefore an important role in the management of the infrastructure. It is a crucial a step towards the digitalisation of our infrastructure and existing processes. Although there are many use cases for monitoring that have already been successfully implemented, monitoring is not yet widely used by German road authorities due to several challenges that were also identified within the scope of the project. Therefore, a guide has been developed in which the current obstacles related to monitoring are identified and possibilities for integrating monitoring into existing processes are offered. To ensure optimal alignment with the needs of road authorities, both an online survey and a workshop have been conducted. The results are summarised in a brochure that is made available to authorities to improve the use of monitoring in Germany. This paper presents the guideline and the brochure.
T2 - 10th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam, Germany
DA - 10.06.2024
KW - Verkehrsinfrastrukturen
KW - Engineering Structures
KW - Bridges
KW - Structural Health Monitoring
KW - Guideline
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612821
UR - https://www.ndt.net/search/docs.php3?id=29582
DO - https://doi.org/10.58286/29582
SN - 1435-4934
VL - 29
IS - 7
SP - 1
EP - 8
PB - NDT.net GmbH & Co. KG
CY - Mayen
AN - OPUS4-61282
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Thiele, Marc
A1 - Löhr, Manuel
A1 - Loewe, Anna
A1 - Degener, Sebastian
A1 - Herrmann, Ralf
T1 - Acoustic emission for monitoring of fatigue damage in concrete elements of wind turbine towers
N2 - Wind energy has become an important player in the energy transition in Germany. Towers of onshore wind turbines are often designed as hybrid structures: the lower part is made of prestressed concrete whereas the upper part is made of steel tubes. The tall structures are permanently subjected to cyclic loads. A research project of BAM as part of the joint project WinConFat - Structure focusses on the evelopment of techniques to monitor fatigue damage evolution in the concrete part. Results of a previous project show that a combination of ultrasonic and acoustic emission testing can give an indication for critical conditions near the end of the fatigue life of the concrete. In the ongoing project acoustic emission sensors have been installed at the base and at the transition piece between concrete and steel of a hybrid wind turbine tower. Beside of acoustic emission measurement the sensor spacing allows for measuring the concrete ultrasonic velocity along the circumference in both levels. Additional measurements like strain, temperature, inclination, or acceleration allow for comparison of environmental loads and change of acoustic properties of the concrete. The paper focusses on first acoustic measurements recorded since December 2023 in comparison to operating data of the wind turbine.
T2 - EWGAE2024: 36th Conference of the European Working Group on Acoustic Emission
CY - Potsdam, Germany
DA - 18.09.2024
KW - Concrete fatigue monitoring
KW - Acoustic emission
KW - Ultrasound
KW - Hybrid wind turbine tower
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612197
DO - https://doi.org/10.58286/30234
SN - 1435-4934
VL - 29
IS - 10
SP - 1
EP - 9
AN - OPUS4-61219
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Munsch, Sarah Mandy
A1 - Klewe, Tim
A1 - Schumacher, K.
A1 - Telong, Melissa
A1 - Grobla, Lili
A1 - Völker, C.
A1 - Yared, K.
A1 - Kruschwitz, Sabine
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Anwendung von KI für die Materialoptimierung im Bauwesen
N2 - Diese Arbeit untersucht den Einsatz von Künstlicher Intelligenz (KI) in der Materialentwicklung für Beton, mit einem Fokus auf Karbonatisierungswiderstand, CO₂-Reduktion und Kostenoptimierung. Das KI-Tool SLAMD, das auf inverses Materialdesign setzt, konnte in Studien die Entwicklungszeit für Betonmischungen um bis zu 80 % verkürzen. Durch die Integration zusätzlicher 1H-Kernspinresonanz-Daten wurde der Prozess um weitere 40 % beschleunigt. Insgesamt zeigt sich, dass der Einsatz von KI die Effizienz und Nachhaltigkeit in der Materialentwicklung signifikant steigern kann.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Künstliche Intelligenz (KI)
KW - Materialoptimierung
KW - Bauwesen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612949
SN - 978-3-9818564-7-7
SP - 192
EP - 200
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61294
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Unger, Jörg F.
A1 - Tamsen, Erik
A1 - Agrawal, A.
A1 - Koutsourelakis, P.-S.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Von Messdaten zum optimierten Bauteil durch Kombination von Material- und Strukturdesign
N2 - Die Entwicklung eines optimierten Designs für Bauwerke erfordert die Berücksichtigung sowohl des Materials als auch des Strukturdesigns. Ziel des Beitrages ist die Vorstellung eines Designprinzips basierend auf automatisierten Workflows, das am Beispiel eines Biegebalkendesign zur Reduzierung des Treibhauspotenzials vorgestellt wird. Eine ganzheitliche Optimierung berücksichtigt Material- und Strukturdesign. Es werden physikalische Modelle mit Ansätzen aus dem maschinellen Lernen kombiniert, die mit experimentellen Daten kalibriert bzw. trainiert werden. Eine besondere Bedeutung hat dabei die Berücksichtigung von Unsicherheiten.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Materialdesign
KW - Strukturdesign
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613003
SN - 978-3-9818564-7-7
SP - 209
EP - 217
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61300
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Telong, Melissa
A1 - Zoriyatkha, Aida
A1 - Pirskawetz, Stephan
A1 - Meng, Birgit
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Beton-Datenmanagement anhand von wissensbasierten Datenstrukturen unter Nutzung von Ontologien und Wissensgraphen
N2 - Im Rahmen der Entwicklung von Betonrezepturen, bei der Betonherstellung und während der Nutzungsphase im Bauwerk, wird eine Vielzahl von Materialdaten generiert. LeBeDigital (Lebenszyklus von Beton - Ontologie- Entwicklung für die Prozesskette der Betonherstellung) ist ein Verbundprojekt innerhalb der Initiative Plattform Material Digital. Das Projekt zielt darauf ab, eine Struktur für Betonmaterialdatenbanken zu entwickeln, die dem FAIR-Prinzip folgt und sowohl praxisnah als auch flexibel genug ist, um zukünftige Entwicklungen in der Betonforschung und -produktion zu unterstützen. Ontologien stellen ein geeignetes Werkzeug zur Generierung von Wissensgraphen dar, um Workflows zur automatisierten Datenerfassung und zur semantischen Datenabfrage zu gestalten. Daher ist die Erarbeitung betonspezifischer Ontologien zentraler Bestandteil des Verbundprojektes, das dazu beitragen will, die Vorrausetzungen für eine Teilhabe der Betonbranche am digitalen Wandel im Bereich der Materialforschung zu sichern.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Beton-Datenmanagement
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612984
SN - 978-3-9818564-7-7
SP - 201
EP - 208
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61298
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Herrmann, Ralf
A1 - Hille, Falk
A1 - Pitters, S.
A1 - Ramasetti, Eshwar Kumar
A1 - Schneider, Ronald
A1 - Wedel, F.
A1 - Hindersmann, I.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Föderiertes Datenmanagement von Monitoringdaten aus Structural Health Monitoring Anwendungen und daraus gewonnenen Trainingsdaten bei Spannbetonbrücken
N2 - Beim Structural Health Monitoring entstehen eine Vielzahl von Daten, Metadaten und Modellen mit hohem Wert für die Beurteilung des Bauwerkszustands und der Prognose von Veränderungen. Kontinuierlich anwachsende Datenbestände müssen nachhaltig geteilt, genutzt und über die Bauwerkslebensdauer archiviert werden. Dabei stellen die Vielfalt der Messaufgaben, die Heterogenität der Daten, die dezentrale Erfassung und z. T. der Umfang eine Herausforderung für die beteiligten Akteure dar. Für den Datentransfer der Monitoringdaten zwischen der Straßenbauverwaltung und den Monitoringausführenden wird ein flexibles Abstimmungsverfahren vorgeschlagen und ein Lösungskonzept für ein föderiertes Datenmanagement skizziert. Eine weitere Herausforderung stellt die bauwerksübergreifende Zusammenstellung von Trainingsdaten für konkrete KI-Anwendungen dar.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Structural Health Monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612902
SN - 978-3-9818564-7-7
SP - 178
EP - 185
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61290
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hille, Falk
A1 - Herrmann, Ralf
A1 - Pitters, S.
A1 - Hindersmann, I.
A1 - Schneider, Ronald
A1 - Wedel, F.
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Leitfaden für den strategischen Einsatz von Monitoring an Straßenbrücken
N2 - Für die Anwendung von Structural Health Monitoring (SHM) im Rahmen des Managements von Straßenbrü-cken wurde zur Unterstützung von Straßenbauverwaltungen, Ingenieurbüros, Bauunternehmen und weiteren Akteuren die Erstellung eines Leitfadens initiiert. Dieser Leitfaden stellt typische Anwendungsfälle für Monito-ring vor und schlägt für diese bewährte Herangehensweisen vor. Darüber hinaus bietet der Leitfaden Empfeh-lungen für Ausschreibung und Vergabe von Monitoringleistungen, eine Anleitung zur Bewertung des wirt-schaftlichen Nutzens von SHM, Hinweise zur optimal einsetzbaren Messtechnik sowie einen Ansatz für das Datenmanagement zur Integration der Monitoringdaten in das Brückenmanagement.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Leitfaden
KW - Monitoring
KW - Straßenbrücke
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612931
SN - 978-3-9818564-7-7
SP - 186
EP - 191
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61293
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Müller-Vahl, H. F.
A1 - Nayeri, C. N.
A1 - Paschereit, C. O.
A1 - Greenblatt, D.
T1 - Airfoil synchronous surging and pitching
N2 - Combined surging and pitching of an airfoil at the identical frequency (i.e. synchronously), at four different phase differences, was investigated theoretically and experimentally. The most general unsteady theoretical formulation was adopted to calculate the lift coefficient, and then extended to explicitly compute the unsteady bound vortex sheet. This was used for comparison with experiments and facilitated the computation of both Joukowsky and impulsive-pressure lift contributions. Experiments were performed using a symmetric 18 % thick airfoil in an unsteady wind tunnel at an average Reynolds number of 3.0*10^5 , with a free-stream oscillation amplitude of 51 %, an angle-of-attack range of 2° +- 2° and a reduced frequency of 0.097. In general, excellent correspondence was observed between theory and experiment, representing the first direct experimental validation of the general theory. It was shown, both theoretically and experimentally, that the lift coefficient was not accurately represented by independent superposition of surging and pitching effects, due to variations in the instantaneous effective reduced frequency not accounted for during pure pitching. Deviations from theory, observed at angle-of-attack phase leads of 90° and 180°, were attributed to bursting of separation bubbles during the early stages of the acceleration phase. The largest deviations occurred when the impulsive-pressure lift contribution was small relative to the Joukowsky contribution, because the latter was most affected by bubble bursting. Bubble bursting resulted in large form-drag oscillations that occurred at identical phase angles within the oscillation cycle, irrespective of the phase difference between surging and pitching, as well as in the absence of pitching.
KW - Unsteady aerodynamics
KW - Dynamic stall
KW - Separation bubble
KW - Bubble bursting
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630068
DO - https://doi.org/10.1017/jfm.2025.220
SN - 1469-7645
VL - 1009
SP - 1
EP - 33
PB - Cambridge University Press (CUP)
AN - OPUS4-63006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosenbusch, Sjard Mathis
A1 - Balzani, D.
A1 - Unger, Jörg F.
T1 - Regularization of softening plasticity models for explicit dynamics using a gradient-enhanced modified Johnson–Holmquist model
N2 - The behavior of concrete under high strain rates is often described by plasticity models with softening, which is modeled by a reduction of the yield surface as a function of the local equivalent plastic strain. Many of these models are local and therefore produce mesh-dependent results. In this contribution, the gradient-enhancement of such models is investigated to mitigate the mesh-dependency.
First, the mesh-dependency of these local formulations based on the analysis with a modified JH2 model as a representative for these constitutive formulations is demonstrated using a one-dimensional benchmark example. In the benchmark, the width of the damaged zone decreases upon mesh-refinement and the dissipated plastic energy tends to zero. It is further shown that a significantly small safety factor for the critical time step is needed in order to achieve accurate results for the benchmark example.
The first investigated gradient-enhancement approach replaces the equivalent local plastic strain with its nonlocal counterpart. The enhancement is based on the inclusion of inertia and damping to the additional Helmholtz equation which enables the use of the central difference method as an explicit solver. This method successfully distributes the damage over several elements, however, the local equivalent plastic strain still localizes into one cell. The inclusion of hardening with respect to the local equivalent plastic strain inhibits the localization and the dissipated plastic energy converges with mesh-refinement.
This is further confirmed in a two-dimensional wedge-splitting experiment and a four-point bending test where the damage pattern produced by the local model is mesh-dependent as well and the dissipated plastic energy tends to zero with mesh-refinement. The proposed nonlocal model with hardening results in a consistent damage pattern and the dissipated plastic energy converges. Furthermore, the nonlocal model with hardening is less sensitive to time step refinement, such that computational efficiency can be improved compared to the local model. The numerical experiments are implemented using the free open source tool FEniCSx and have been made available on Zenodo.
KW - Gradient plasticity
KW - Explicit dynamics
KW - JH2 model
KW - Concrete modeling
KW - FEniCS
KW - Mesh convergence
KW - Time step convergence
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630453
DO - https://doi.org/10.1016/j.ijimpeng.2024.105209
SN - 1879-3509
VL - 198
SP - 1
EP - 18
PB - Elsevier Ltd.
CY - Schweiz
AN - OPUS4-63045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosenbusch, Sjard Mathis
A1 - Diercks, Philipp
A1 - Kindrachuk, Vitaliy
A1 - Unger, Jörg F.
T1 - Integrating custom constitutive models into FEniCSx: A versatile approach and case studies
N2 - The development and integration of user-defined constitutive relationships into finite element (FE) tools using standardized interfaces play a pivotal role in advancing the capabilities of FE solvers for structural mechanics applications. While commercial FE solvers like Abaqus and Ansys have designed their interfaces to provide custom stresses, tangents, and updated history variables, the open-source solver FEniCSx remains efficient only when the constitutive update has an analytical representation. This restricts the application of FEniCSx for non-linear structural mechanics.
Since FEniCSx has become a powerful and popular open-source tool for solving partial differential equations, particularly due to its automatic computation of Hessians, we aim to develop a generalized interface to enhance its capability for constitutive modeling. This approach will address complex constitutive equations that require iterative solutions at the quadrature point level. Specific implementation challenges, such as using return-mapping procedures, can then be managed commonly. The provided interface for custom constitutive models offers a versatile way to implement them in various languages, including C++, Python, Rust, and Fortran. Finally, with UMATs for viscoplastic models as an example, we demonstrate how existing user subroutines can be incorporated into the interface and utilized within the FEniCSx framework.
KW - Finite element method
KW - Constitutive models
KW - FEniCSx
KW - UMAT
KW - Rust
KW - Python
KW - C++
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630439
DO - https://doi.org/10.1016/j.advengsoft.2025.103922
SN - 0965-9978
VL - 206
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-63043
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwettmann-Lui, Kim
A1 - Nytus, Nina
A1 - Weigel, Sandra
A1 - Radenberg, Martin
A1 - Stephan, Dietmar
T1 - Effect of multiple-repeated aging and rejuvenation processes on bitumen properties evaluated with physical and chemical tests and multivariate analysis methods
N2 - This paper presents laboratory experiments on repeated bitumen aging and rejuvenation processes to assess multiple reuse feasibility. Three 50/70 penetration-graded bitumen samples were reused with four different rejuvenators without adding virgin binder. The experiments continued until significant material changes, such as inhomogeneities and increased stickiness, prevented reliable characterization. After each rejuvenation and aging process, physical and chemical properties were analyzed, resulting in a comprehensive dataset. Results indicate that the reuse of pure rejuvenators, without incorporating virgin binder, is limited. Cyclic reuse depends heavily on the rejuvenator and its interaction with the binder. Of the four rejuvenators tested, two bio-based products enabled the maximum reuse of four cycles. Therefore, the rejuvenators used in this project are more suitable as additives to improve the physical properties of the bitumen for reuse rather than as substitutes for the binder. The datasets were further evaluated using multivariate analysis methods to construct statistical models for two use cases: In the first use case, the samples are classified by their aging condition. In the second use case, the samples are differentiated according to the rejuvenators. The models were successfully validated, providing a promising framework for the classification of unknown bitumen samples for reuse.
KW - Bitumen
KW - Aging
KW - Rejuvenation
KW - Multiple recycling
KW - DSR measurements
KW - Reuse
KW - FTIR spectroscopy
KW - Multivariate analysis methods
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627563
DO - https://doi.org/10.1016/j.conbuildmat.2025.140734
SN - 1879-0526
VL - 472
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-62756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sigrüner, M.
A1 - Hüsken, Götz
A1 - Pirskawetz, Stephan
A1 - Herz, J.
A1 - Muscat, D.
A1 - Strübbe, N.
T1 - Pull-out behavior of polymer fibers in concrete
N2 - The bond between polymer fibers and the surrounding cementitious matrix is essential for the development of concrete reinforcement. The single fiber pull-out test (SFPT) is the standard characterization technique for testing the bond strength. However, the different phases of debonding cannot be distinguished by the SFPT. This study investigates the debonding of different polymer fibers from the surrounding cementitious matrix with a modified SFPT and proposes methods to change the SFPT setup to generate more valuable information on the debonding mechanism. The SFPT was equipped with linear variable differential transformers (LVDT), digital image correlation (DIC) and acoustic emission (AE) analysis. The results demonstrate that the modified SFPT allows a better understanding of the different phases of debonding during fiber pull-out. Furthermore, bond strength values calculated by different methods reveal that the chemical bond of the investigated polymers is not different as reported by previous studies. Deformation measurements performed using LVDTs and DIC are suitable measuring techniques to characterize the debonding mechanism in SFPT. A correlation between recorded AE and debonding phases was not found.
KW - Polymer Fibres
KW - Concrete
KW - Pull-Out Behaviour
KW - Debonding Mechanism
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582918
DO - https://doi.org/10.1002/pol.20230264
SN - 2642-4169
SP - 1
EP - 13
PB - Wiley Periodicals, LLC.
AN - OPUS4-58291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
T1 - Richtlinie „Detektion von Spanndrahtbrüchen mit Schallemission“
N2 - Ein großer Teil unserer Brücken wurden in den 1950er bis 1970er Jahren als Spannbetonbrücken gebaut. Mit der damals noch relativ jungen Technologie entstanden elegante, teilweise gewagte Bauwerke mit großen Spannweiten, welche die Vorteile der Materialien Stahl und Beton geschickt kombinieren. Die Standsicherheit einiger dieser Brücken ist heute gefährdet. Die Ursachen liegen in der enorm gewachsenen Belastung durch Schwerverkehr, teilweise ungenügender Wartung und in konstruktiven und Materialschwächen, die der mangelnden Erfahrung mit der Technologie in der Bauzeit geschuldet sind. Ein neuralgischer Punkt der Bauwerke sind die in den Beton integrierten Spannglieder.
Infolge von Korrosion und Ermüdung können Elemente der Spannglieder reißen, wodurch die für das Tragwerk notwendige Spannung und somit die Tragfähigkeit reduziert werden. Nicht bei allen Brücken kündigen sichtbare Risse im Beton oder auffällige Verformungen den Tragfähigkeitsverlust bzw. das finale Versagen rechtzeitig an.
Die Schallemissionsanalyse ist die derzeit einzige Methode, das Reißen einzelner Spannstähle zuverlässig und mit wirtschaftlich vertretbarem Aufwand zu detektieren. Trotzdem es schon einige Spannbetonbauwerke gibt, die mit Schallemissionsanalyse überwacht werden, ist das Verfahren noch wenig bekannt.
Außerdem fehlen technische Richtlinien, was die Ausschreibung und Vergabe von entsprechenden Aufträgen und die Bewertung der Angebote sehr erschwert. Um sowohl Baulastträger als auch Dienstleistungsanbieter in den Vergabeverfahren und im Betrieb der Monitoringsysteme zu unterstützen, hat sich eine Gruppe von Experten aus den Bereichen Bauingenieurwesen und Schallemission zum Entwurf einer Richtlinie „Detektion von Spanndrahtbrüchen mit Schallemission“ zusammengefunden. Mit diesem Beitrag wird die Richtlinie vorgestellt, deren Bearbeitung bis zur SCHALL 23 abgeschlossen sein soll.
T2 - SCHALL 23 Entwicklung und Anwendung der Schallemissionsanalyse und Zustandsüberwachung mit geführten Wellen
CY - Wetzlar, Germany
DA - 21.03.2023
KW - Schallemission
KW - Spannbeton
KW - Brücke
KW - Spannstahlbruch
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573904
SP - 1
EP - 4
PB - DGZfP
CY - Berlin
AN - OPUS4-57390
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hirthammer, Volker
A1 - Unger, Jörg F.
A1 - Ozbolt, J.
ED - von Scheven, M.
ED - Keip, M.-A.
ED - Karajan, N.
T1 - Mesoscale influence on the macroscopic material behavior of concrete
N2 - The heterogeneous mesostructure of concreted causes local stress concentrations. Stress dependent phenomena like damage and creep as well as their interactions are effected by those stress
concentrations. Therefore a material model’s macroscopic behavior will differ whether the mesoscale structure is considered or not. The differences between the mesoscale approach and an homogeneous approach will be presented. The results are discussed with focus on the true materials behavior.
T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry
CY - Stuttgart, Germany
DA - 11.10.2017
KW - Mesoscale
KW - Material behavior
KW - Macroscopic
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436611
DO - https://doi.org/10.18419/opus-9334
VL - 7
SP - MS13, 414
EP - 417
PB - Institute for Structural Mechanics, University of Stuttgart
CY - Stuttgart
AN - OPUS4-43661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pohl, Christoph
A1 - Unger, Jörg F.
ED - von Scheven, M.
ED - Keip, M.-A.
ED - Karajan, N.
T1 - Obtaining macroscopic properties from a mesoscale thermomechanical model of concrete
N2 - A coupled thermomechanical mesoscale model for concrete under heating is presented. When considering the heterogeneous structure under coupled loads, complex macroscopic material properties can be modelled using simple constitutive relations. For instance, damage evolution is directly driven by the incompatibility of thermal strains between matrix and aggregates. Without prescribing
fc = f(T), a decline in compressive strength with rising temperatures will be shown.
T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry
CY - Stuttgart, Germany
DA - 11.10.2017
KW - Multiscale
KW - Concrete mesoscale
KW - Thermomechanical
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436540
DO - https://doi.org/10.18419/opus-9334
VL - 7
SP - MS13, 418
EP - 422
PB - Institute for Structural Mechanics, University of Stuttgart
CY - Stuttgart
AN - OPUS4-43654
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huschke, Philip
A1 - Unger, Jörg F.
ED - von Scheven, M.
ED - Keip, M.-A.
ED - Karajan, N.
T1 - Domain decomposition methods for fracture mechanics problems and its application to fiber reinforced concrete
N2 - A finite element tearing and interconnecting (FETI) approach for phase-field models and Gradient enhanced damage models is presented. These diffusive crack models can solve fracture mechanics problems by integrating a set of partial differential equations and thus avoid the explicit treatment of discontinuities. However, they require a fine discretization in the vicinity of the crack. FETI methods distribute the computational cost among multiple processors and thus speed up the computation.
T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry
CY - Stuttgart, Germany
DA - 11.10.2017
KW - FETI
KW - Domain decomposition methods
KW - Fracture mechanics problems
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436764
DO - https://doi.org/10.18419/opus-9334
VL - 7
SP - 444
EP - 448
PB - Institute for Structural Mechanics, University of Stuttgart
CY - Stuttgart
AN - OPUS4-43676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Titscher, Thomas
A1 - Unger, Jörg F.
A1 - Oliver, J.
ED - von Scheven, M.
ED - Keip, M.-A.
ED - Karajan, N.
T1 - Cycle-by-cycle fatigue damage model for concrete
N2 - Damage caused by stress concentrations in the complex mesoscopic geometry of concrete leads to continuous stress redistribution over the material’s life time. The presented fatigue damage model
captures this by resolving each load cycle in a cycle-by-cycle time integration. The model extends a static damage model to failure caused by the (time dependent) strain amplitudes and, thus, allows calibrating the majority of the material’s parameters in static experiments.
T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry
CY - Stuttgart, Germany
DA - 11.10.2017
KW - Cycle-by-cycle
KW - Fatigue damage
KW - Mesoscopic
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436681
DO - https://doi.org/10.18419/opus-9334
VL - 7
SP - MS13, 440
EP - 443
PB - Institute for Structural Mechanics, University of Stuttgart
CY - Stuttgart
AN - OPUS4-43668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Kruschwitz, Sabine
T1 - Monitoring of the absolute water content in porous materials based on embedded humidity sensors
N2 - Moisture transport monitoring may indicate the onset of deterioration in porous building materials Prior to damage occurring. Most moisture measurement systems provide only qualitative values, require extensive calibration, or are destructive. Thus, non-destructive and calibration-free monitoring Systems are required. Our approach of moisture monitoring is to embed sensors that measure the relative humidity.
In our experiment, screed samples are monitored during the Hydration and evaporation process. Every test sample is equipped with 10 embedded sensors which measure the relative humidity across the sample thickness. Based on Hillerborg’s approach, the relative humidity is converted into the corresponding pore saturation. In our study, the free water is computed without knowledge of the Sorption isotherm. The free water in the pore system is predicted and validated. The predicted weight decrease corresponds conclusively to gravimetrically measured weights. The embedded sensors yield the absolute liquid water content and enable an experimental, non-destructive monitoring of liquid water in porous materials.
KW - Moisture measurements
KW - Porous materials
KW - Embedded sensors
KW - Partial pore saturation
KW - Sorption isotherm
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453476
DO - https://doi.org/10.1016/j.conbuildmat.2018.05.044
SN - 0950-0618
VL - 177
SP - 511
EP - 521
PB - Elsevier
AN - OPUS4-45347
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Coelho Lima, Isabela
A1 - Robens-Radermacher, Annika
A1 - Titscher, Thomas
A1 - Kadoke, Daniel
A1 - Koutsourelakis, P.-S.
A1 - Unger, Jörg F.
T1 - Bayesian inference for random field parameters with a goal-oriented quality control of the PGD forwardmodel's accuracy
N2 - Numerical models built as virtual-twins of a real structure (digital-twins) are considered the future ofmonitoring systems. Their setup requires the estimation of unknown parameters, which are not directly measurable. Stochastic model identification is then essential, which can be computationally costly and even unfeasible when it comes to real applications. Efficient surrogate models, such as reduced-order method, can be used to overcome this limitation and provide real time model identification. Since their numerical accuracy influences the identification process, the optimal surrogate not only has to be computationally efficient, but also accurate with respect to the identified parameters. This work aims at automatically controlling the Proper Generalized Decomposition (PGD) surrogate’s numerical accuracy for parameter identification. For this purpose, a sequence of Bayesian model identification problems, in which the surrogate’s accuracy is iteratively increased, is solved with a variational Bayesian inference procedure. The effect of the numerical accuracy on the resulting posteriors probability density functions is analyzed through two metrics, the Bayes Factor (BF) and a criterion based on the Kullback-Leibler (KL) divergence. The approach is demonstrated by a simple test example and by two structural problems. The latter aims to identify spatially distributed damage, modeled with a PGD surrogate extended for log-normal random fields, in two different structures: a truss with synthetic data and a small, reinforced bridge with real measurement data. For all examples, the evolution of the KL-based and BF criteria for increased accuracy is shown and their convergence indicates when model refinement no longer affects the identification results.
KW - Variational inference
KW - Proper generalized decomposition
KW - Goal-oriented
KW - Digital twin
KW - Random field
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555755
DO - https://doi.org/10.1007/s00466-022-02214-6
SN - 1432-0924
SP - 1
EP - 22
PB - Springer
CY - Berlin
AN - OPUS4-55575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pohl, Christoph
A1 - Smilauer, V.
A1 - Unger, Jörg F.
T1 - A three-phase transport model for high-temperature concrete simulations validated with X-ray CT data
N2 - Concrete exposure to high temperatures induces thermo-hygral phenomena, causing water phase changes, buildup of pore pressure and vulnerability to spalling. In order to predict these phenomena under various conditions, a three-phase transport model is proposed. The model is validated on X-ray CT data up to 320 ◦C, showing good agreement of the temperature profiles and moisture changes. A dehydration description, traditionally derived from thermogravimetric analysis, was replaced by a formulation based on data from neutron radiography. In addition, treating porosity and dehydration evolution as independent processes, previous approaches do not fulfil the solid mass balance. As a consequence, a new formulation is proposed that introduces the porosity as an independent variable, ensuring the latter condition.
KW - Concrete
KW - Porous media
KW - Spalling
KW - Dehydration
KW - Moisture transport
KW - Heat transfer
KW - Pore pressure
KW - Porosity
KW - Finite elements
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532840
UR - https://doi.org/10.5281/zenodo.4890635
DO - https://doi.org/10.3390/ma14175047
SN - 1996-1944
VL - 14
IS - 17
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-53284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klewe, Tim
A1 - Strangfeld, Christoph
A1 - Ritzer, Tobias
A1 - Kruschwitz, Sabine
T1 - Combining Signal Features of Ground-Penetrating Radar to Classify Moisture Damage in Layered Building Floors
N2 - To date, the destructive extraction and analysis of drilling cores is the main possibility to obtain depth information about damaging water ingress in building floors. The time- and costintensive procedure constitutes an additional burden for building insurances that already list piped water damage as their largest item. With its high sensitivity for water, a ground-penetrating radar (GPR) could provide important support to approach this problem in a non-destructive way. In this research, we study the influence of moisture damage on GPR signals at different floor constructions. For this purpose, a modular specimen with interchangeable layers is developed to vary the screed and insulation material, as well as the respective layer thickness. The obtained data set is then used to investigate suitable signal features to classify three scenarios: dry, damaged insulation, and damaged screed. It was found that analyzing statistical distributions of A-scan features inside one B-scan allows for accurate classification on unknown floor constructions. Combining the features with multivariate data analysis and machine learning was the key to achieve satisfying results. The developed method provides a basis for upcoming validations on real damage cases.
KW - Radar
KW - Material Moisture
KW - Non-destructive testing
KW - Signal Features
KW - Civil Engineering
KW - Machine Learning
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533606
DO - https://doi.org/10.3390/app11198820
VL - 11
IS - 19
SP - 8820
PB - MDPI
AN - OPUS4-53360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Breithaupt, Mathias
A1 - Strangfeld, Christoph
T1 - Distributed Humidity Sensing in Concrete Based on Polymer Optical Fiber
N2 - We present a preliminary investigation on distributed humidity monitoring during the drying process of concrete based on an embedded polymer optical fiber (POF). The water dissipated into the POF changes several properties of the fiber such as refractive index, scattering coefficient and attenuation factor, which eventually alters the Rayleigh backscattered light. The optical time Domain reflectometer (OTDR) technique is performed to acquire the backscattered signal at the wavelengths 650 nm and 500 nm, respectively. Experimental results show that the received signal increases at 650 nm while the fiber attenuation factor clearly increases at 500 nm, as the concrete dries out. In the hygroscopic range, the information retrieved from the signal change at 650 nm agrees well with the measurement result of the electrical humidity sensors also embedded in the concrete sample.
KW - Distributed fiber optic sensing
KW - Distributed humidity sensing
KW - Polymer optical fibers
KW - Concrete drying
KW - Material moisture
KW - Embedded humidity sensors
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537644
DO - https://doi.org/10.3390/polym13213755
SN - 2073-4360
VL - 13
IS - 21
SP - 3755
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-53764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sittner, Jonathan
A1 - Götze, Jens
A1 - Müller, Axel
A1 - Renno, Axel D.
A1 - Ziegenrücker, René
A1 - Pan, Yuanming
T1 - Trace element analysis and luminescence behavior of quartz in pegmatites of the Tørdal Region, Norway
N2 - This publication presents a study on the mineral chemistry and luminescence properties of quartz samples from pegmatites of the Tørdal region in Norway. A total of 12 samples were analyzed using Secondary Ion Mass Spectrometry (SIMS), Electron Paramagnetic Resonance Spectroscopy (EPR), and Cathodoluminescence (CL) to gain insights into their trace element concentration and distribution as well as their luminescence behavior. The samples are characterized by different Cl emissions at 450 nm, 500 nm 650 nm and an additional shoulder at 390 nm, which is only partially visible due to the absorption of the glass optics. Of these luminescence bands, the 500 nm band is the most dominant in most samples and it is characterized by an initial blue-green luminescence, which is not stable under electron irradiation. Moreover, it is characterized by a heterogeneous distribution within the samples. This luminescence can be mostly assigned to [AlO4/M+]0 defects, with charge compensation mostly achieved by Li+. Analyses by EPR spectroscopy prove the dominance of structurally bound Al, Li, and Ti ions in the investigated samples. Further analyses using SIMS mapping demonstrate that Na and K are mainly bound to micro fractures or inclusions, suggesting a limited role in the compensation of the luminescence centers. Additionally, the SIMS mappings show that some samples contain Al-rich clusters of 10 to 20 µm in diameter, whereas other trace elements are characterized by a homogeneous distribution. These clusters correspond to bright luminescence areas in size and shape and could potentially indicate H+ compensated [AlO4/M+]0 defects.
KW - Quartz
KW - Trace elements
KW - SIMS
KW - Cathodoluminescence
KW - EPR
KW - Tørdal
KW - Pegmatite
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612529
DO - https://doi.org/10.1016/j.chemgeo.2024.122427
VL - 670
SP - 1
EP - 15
PB - Elsevier BV
AN - OPUS4-61252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüsken, Götz
A1 - Jeyifous, Olubunmi Anthony
A1 - Schönsee, Eric
A1 - Strangfeld, Christoph
T1 - An assessment of the repeatability of 3D printed concrete structures
N2 - Additive manufacturing of concrete structures, also known as 3D concrete printing, is a technology that received a lot of attention over the past decade due to its financial an ecological advantage as sustainable construction technology. Although several techniques and approaches demonstrate these advantages, quality control during printing is highly challenging and rarely applied and harmonized standards are not existing. Due to the continuous mixing process used in 3D concrete printing, it is impossible to exclude variations in the dry mixture or water content, and a single test sample is insufficient to be representative for the whole structure. A defect in one layer during the printing can affect the entire integrity of the whole structure. This study shows the results of an arch designed as framework structure that was printed multiple times under the same boundary conditions using an extrusion-based 3D concrete printer. Each arch was tested for its mechanical strength and load bearing behavior. The results of the mechanical testing of the printed arches are compared with material data obtained by classical tests and discussed regarding their statistical significance.
T2 - Digital Concrete 2024
CY - Munich, Germany
DA - 04.09.2024
KW - 3D concrete printing
KW - Repeatability
KW - Monitoring
KW - Process control
KW - Quality control
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611012
DO - https://doi.org/10.24355/dbbs.084-202408150641-0
SP - 1
EP - 9
PB - TU Braunschweig
AN - OPUS4-61101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Algernon, A.
A1 - Walther, A.
A1 - Denzel, W.
A1 - Ebsen, B.
A1 - Feistkorn, S.
A1 - Friese, M.
A1 - Grosse, C.
A1 - Kathage, S.
A1 - Kessler, S.
A1 - Köpp, Christian
A1 - Krause, M.
A1 - Maack, Stefan
A1 - Schickert, M.
A1 - Taffe, A.
A1 - Timofeev, Juri
A1 - Wilcke, M.
A1 - Wolf, J.
T1 - Qualitätssicherung und Validierung der Anwendung zerstörungsfreier Prüfungen von Stahlbetonbauteilen im Bauwesen
N2 - Stahlbetontragwerke sind eine wichtige Konstruktionsweise im Bauwesen und ein wachsendes Anwendungsfeld für die Zerstörungsfreie Prüfung (ZfP).
Zur Sicherung der Tragsicherheit, strukturellen Integrität, Bestimmung von Geometrien und zur Detektion konstruktiver Elemente wie z.B. Bewehrung, Verankerungen und Spannkanälen besitzen zerstörungsfreie Prüfverfahren in diesem Bereich inzwischen große Relevanz. Durch den bislang erreichten Fortschritt in der Forschung und Entwicklung haben moderne akustische und elektromagnetische Verfahren eine beachtliche Leistungsfähigkeit erreicht. Von Geräteherstellern sind diese in kommerziellen Produktserien umgesetzt worden und finden eine zunehmend breite Anwendung in der Praxis. In einigen anderen Anwendungsgebieten, in denen die ZfP bereits fester Bestandteil von Überwachungen ist, wie z.B. im Maschinenbau und insbesondere in der Kerntechnik und der Luftfahrt, existieren umfangreiche Qualitätssicherungssysteme für die konforme Anwendung und zuverlässige Einbeziehung der ZfP. Dem relativ jungen Entwicklungsstadium moderner ZfP für Stahlbetonbauteile entsprechend müssen solche Konzepte im Bauwesen erst noch entwickelt bzw. implementiert werden.
Dementsprechend hat sich der Unterausschuss Qualitätssicherung (UA- S) des Fachausschusses ZfP im Bauwesen (ZfPBau) die Definition und Verbesserung der Qualität von ZfP-Anwendungen sowie insbesondere die verfahrensunabhängige Standardisierung von Prüfprozeduren und statistische Absicherung der Prüfergebnisse zum Ziel gemacht.
Die aktuellen Arbeitsfelder beinhalten die Entwicklung praxisgerechter Konzepte für Prüfprozeduren und deren Erprobung in einem Ringversuch sowie die Konzeption von Testkörpern hinsichtlich unterschiedlicher Aspekte wie Parameterstudien, Validierung, Kalibrierung und Simulation. Dabei werden Ansätze anderer Branchen durchaus einbezogen, die Anpassung an die spezifischen Bedürfnisse und Gegebenheiten des Bauwesens wird jedoch als wesentlich angesehen und stellt somit eine wichtige Vorgabe dar.
Da die Tätigkeiten nicht auf einzelne Verfahren begrenzt sind, müssen generelle Vorgehensweisen entwickelt werden, die sich auf die jeweiligen Verfahren konkretisieren lassen. Der Vortrag gibt hierzu erste Einblicke in die Arbeit des Ausschusses.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Zerstörungsfreie Prüfung
KW - Beton
KW - Qualitätssicherung
KW - Validierung
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472417
SP - 1
EP - 9
AN - OPUS4-47241
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pirskawetz, Stephan
A1 - Schmidt, S.
T1 - Detection of wire breaks in prestressed concrete bridges by Acoustic Emission analysis
N2 - problem. One reason is the sensitivity to stress corrosion cracking of the prestressing steel. Failure of prestressing wires can result in collapse of the entire structure without premature indication by transverse bending cracks or considerable deformation. The response of a structure to significant number of prestressing wire breaks was studied on a bridge in Brandenburg, Germany. Two thirds of the prestressing wires in concentrated tendons of two girders were cut before the bridge was demolished. Acoustic Emission Analysis was used to detect the wire breaks. Thus, the number of wire breaks was correlated with results of other measurement techniques, in particular strain measurements on the girders. In preparation of the measurements, the acoustic properties of the bridge were determined and the suitability of Schmidt hammer impacts as an acoustic reference source was validated.
KW - Real scale test
KW - Acoustic emission monitoring
KW - Structural health monitoring (SHM)
KW - Prestressed concrete bridge
KW - Stress corrosion cracking
KW - Wire break
KW - Destructive testing
KW - Nondestructive testing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573927
DO - https://doi.org/10.1016/j.dibe.2023.100151
SN - 2666-1659
VL - 14
SP - 1
EP - 10
PB - Elsevier Ltd
AN - OPUS4-57392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Küttenbaum, Stefan
A1 - Maack, Stefan
A1 - Taffe, A.
A1 - Braml, T.
ED - Sykora, M.
ED - Lenner, R.
ED - de Koker, N.
T1 - On the Treatment of Measurement Uncertainty in Stochastic Modeling of Basic Variables
N2 - The acquisition and appropriate processing of relevant information about the considered system remains a major challenge in assessment of existing structures. Both the values and the validity of computed results such as failure probabilities essentially depend on the quantity and quality of the incorporated knowledge. One source of information are onsite measurements of structural or material characteristics to be modeled as basic variables in reliability assessment. The explicit use of (quantitative) measurement results in assessment requires the quantification of the quality of the measured information, i.e., the uncertainty associated with the information acquisition and processing. This uncertainty can be referred to as measurement uncertainty. Another crucial aspect is to ensure the comparability of the measurement results.This contribution attempts to outline the necessity and the advantages of measurement uncertainty calculations in modeling of measurement data-based random variables to be included in reliability assessment. It is shown, how measured data representing time-invariant characteristics, in this case non-destructively measured inner geometrical dimensions, can be transferred into measurement results that are both comparable and quality-evaluated. The calculations are based on the rules provided in the guide to the expression of uncertainty in measurement (GUM). The GUM-framework is internationally accepted in metrology and can serve as starting point for the appropriate processing of measured data to be used in assessment. In conclusion, the effects of incorporating the non-destructively measured data into reliability analysis are presented using a prestressed concrete bridge as case-study.
T2 - International Probabilistic Workshop 2022 (IPW2022)
CY - Stellenbosch, South Africa
DA - 09.09.2022
KW - Reliability
KW - Assessment
KW - Existing structures
KW - Measurement uncertainty
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556580
DO - https://doi.org/10.14311/APP.2022.36.0109
SN - 2336-5382
VL - 36
SP - 109
EP - 118
PB - Czech Technical University
CY - Prague
AN - OPUS4-55658
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klimek, André
A1 - Stelzner, Ludwig
A1 - Hothan, Sascha
A1 - Rogge, Andreas
T1 - Fire induced concrete spalling in combination with size effects
N2 - The size effect has its origin in fracture mechanics and describes the formation as well as propagation of cracks in brittle and solid materials in dependence of the specimen size. However, the size effect in concrete spalling describes the damage behaviour on a macroscopic scale for different sized specimens in case of fire. Concrete spalling is a very complex and yet not fully understood phenomenon. To reduce the effort of fire tests to analyse the spalling behaviour of concrete mixtures, this study investigates the susceptibility to spalling for six different concrete mixtures and three specimen sizes. The sizes were divided in full scale slabs (1.8 m x 1.2 m x 0.3 m), intermediate scale cuboids (0.6 m x 0.6 m x 0.3 m) and small scale cylinders (Ø0.15 m x 0.3 m). For this purpose, a novel test set-up was built to test six intermediate scale or twelve small scale specimens simultaneously to ensure a similar heating regime for every specimen. All specimens were fire exposed on one side and remained unrestrained. A size effect occurred for four of the six concrete mixtures. Compared to the full scale specimens the spalling was reduced significantly for all smaller specimen sizes. Additionally, spalling did not occur for the small scale specimens. The results show that the specimen size is an essential parameter to investigate the susceptibility to spalling of a concrete mixture. For future investigations the testing conditions must be adjusted for the intermediate scale specimens to recreate the conditions of the slabs.
KW - Concrete
KW - Spalling
KW - Size effect
KW - Fire test
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559231
DO - https://doi.org/10.1617/s11527-022-02051-2
VL - 55
IS - 8
SP - 1
EP - 14
PB - Springer
AN - OPUS4-55923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Küttenbaum, Stefan
A1 - Maack, Stefan
A1 - Taffe, A.
T1 - Approach to the development of a model to quantify the quality of tendon localization in concrete using ultrasound
N2 - Each engineering decision is based on a number of more or less accurate information. In assessment of existing structures, additional relevant information collected with on-site inspections facilitate better decisions. However, observed data basically represents the physical characteristic of interest with an uncertainty. This uncertainty is a measure of the inspection quality and can be quantified by expressing the measurement uncertainty. The internationally accepted rules for calculating measurement uncertainty are well established and can be applied straightforwardly in many practical cases. Nevertheless, the calculations require the occasionally time-consuming development of an individually suitable measurement model. This contribution attempts to emphasize proposals for modelling the non-destructive depth measurement of tendons in concrete using the ultrasonic echo technique. The proposed model can serve as guideline for the determination of the quality of the measured information in future comparable inspection scenarios.
T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2022)
CY - Kapstadt, South Africa
DA - 03.10.2022
KW - Reliability
KW - Measurement Uncertainty
KW - Non-Destructive Testing
KW - Existing Concrete Structures
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559927
DO - https://doi.org/10.1051/matecconf/202236403007
SN - 2261-236X
VL - 364
SP - 1
EP - 8
PB - EDP Sciences
CY - Les Ulis, France
AN - OPUS4-55992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mendler, A.
A1 - Döhler, M.
A1 - Hille, Falk
T1 - Detecting changes in boundary conditions based on sensitivity-based statistical tests
N2 - Structural health monitoring is a promising technology to automatically detect structural changes based on permanently installed sensors. Vibration-based methods that evaluate the global system response to ambient excitation are suited to diagnose changes in boundary conditions, i.e., changes in member prestress or imposed displacements. In this paper, these changes are evaluated based on sensitivity-based statistical tests, which are capable of detecting and localizing parametric structural changes. The main contribution is the analytical calculation of sensitivity vectors for changes in boundary conditions (i.e., changes in prestress or support conditions) based on stress stiffening, and the combination with a numerically efficient algorithm, i.e., Nelson’s method. One of the main advantages of the employed damage diagnosis algorithm is that, although it uses physical models for damage detection, it considers the uncertainty in the data-driven features, which enables a reliabilitybased approach to determine the probability of detection. Moreover, the algorithm can be trained and the probability of detecting future damages can be predicted based on data and a model from the undamaged structure,
in an unsupervised learning mode, making it particularly relevant for unique structures, where no data from the damaged state is available. For proof of concept, a numerical case study is presented. The study assesses the loss of prestress in a two-span reinforced concrete beam and showcases suitable validation approaches for the sensitivity calculation.
T2 - International Symposium on Non-Destructive Testing in Civil Engineering (NDT-CE 2022)
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Nelson’s method
KW - Global ambient vibrations
KW - Asymptotic local approach
KW - Sensitivity vectors
KW - Probability of detection
KW - Stress stiffening
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566632
DO - https://doi.org/10.58286/27311
SN - 1435-4934
VL - 27
IS - 9
SP - 1
EP - 13
PB - NDT.net
CY - Kirchwald
AN - OPUS4-56663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gebauer, D.
A1 - Gutiérrez, R,
A1 - Marx, S.
A1 - Butler, M.
A1 - Grahl, K.
A1 - Thiel, T.
A1 - Maack, Stefan
A1 - Küttenbaum, Stefan
A1 - Pirskawetz, Stephan
A1 - Breit, W.
A1 - Schickert, M.
A1 - Krüger, M.
T1 - Interrelated dataset of rebound numbers, ultrasonic pulse velocities and compressive strengths of drilled concrete cores from an existing structure and new fabricated concrete cubes
N2 - Two test series were examined using nondestructive measuring methods by six independent laboratories before determining their compressive strength. The nondestructive test methods used were the rebound hammer and ultrasonic pulse velocity measurement. Two types of geometries were investigated: drilled cores and cubes. The measurement procedure for each of these datasets is conditioned to the geometry and is therefore different.
The first series consists of 20 drilled cores (approximately diameter/height = 10 cm/20 cm) from the 55-year-old Lahntal Viaduct near Limburg, Germany. After preparation in the first laboratory, the lateral surface of the drilled cores was tested with the rebound hammer using a given pattern. Every laboratory tested every drilled core at different locations.
Ultrasonic measurements in transmission were performed repeatedly at predefined points on the flat surfaces of the specimen.
The second series consisted of 25 newly manufactured concrete cubes of a mix with a target concrete strength class of C30/37. The edge length was 15 cm. Each laboratory received five specimens of this test series. Thus, contrary to the first series, each specimen was tested by only one laboratory. Two side faces of each cube were tested with the rebound hammer. In addition, ultrasonic measurements were performed by one laboratory. The time of flight was measured between the tested side faces of the rebound hammer at different positions.
For both series, rebound hammers were used to determine the R-value as well as the Q-value. The rebound hammer models within the laboratories were always the same, while they differed between the laboratories. The ultrasonic measurements took place with different measurement systems and couplants. Finally, both specimen series were tested destructively for compressive strength.
The dataset contains the raw data summarized in tabular form. In addition, relevant calculated data are included in some cases. For the ultrasonic measurements, the time of flight has already been converted into the ultrasonic velocity. Besides, in addition to the raw data of the compressive strength test (force, weight, and geometry values), the calculated compressive strengths and densities are also provided.
KW - Nondestructive testing
KW - Ultra sound
KW - Rebound hammer
KW - Existing structure
KW - Civil engineering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574655
DO - https://doi.org/10.1016/j.dib.2023.109201
SN - 2352-3409
VL - 48
IS - 109201
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-57465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Capitain, C.
A1 - Schüßler, M.
A1 - Bugsel, B.
A1 - Zweigle, J.
A1 - Vogel, Christian
A1 - Leube, Peter
A1 - Zwiener, C.
T1 - Implementation of matrix-matched semiquantification of PFAS in AFFF-contaminated soil
N2 - This study presents a novel semiquantification approach for nontarget screening (NTS), combining matrix-matched calibration and ionization class-specific average calibration curves (ACCs) to address the lack of analytical reference standards for most per- and polyfluoroalkyl substances (PFAS). Ionization class-specific ACCs for carboxylic and sulfonic acids, sulfonamides, and cationic PFAS result in high accuracy, with median absolute accuracy quotients below 2.27×. The approach was applied to soil impacted by aqueous film-forming foam (AFFF) contamination. A total of 96 tentatively identified PFAS were semiquantified in addition to 28 quantified compounds based on available standards. Semiquantified concentrations exceeded those of target analytes, demonstrating the critical role of this method in capturing broader PFAS contamination. In this case, validation against extractable organofluorine (EOF) showed a 102% closed mass balance. The innovative approach not only enables comprehensive PFAS contamination assessment in complex matrices but also expands the scope of the NTS for environmental monitoring, remediation, and risk assessment of AFFF-contaminated sites.
KW - Per- and polyfluoroalkyl substances (PFAS)
KW - Contaminated soil
KW - Non-targeted analysis
KW - Combustion ion chromatography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629445
DO - https://doi.org/10.1021/acs.est.4c14255
SN - 1520-5851
VL - 59
IS - 14
SP - 7338
EP - 7347
PB - American Chemical Society (ACS)
CY - Columbus, Ohio
AN - OPUS4-62944
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mugani, R.
A1 - El Khalloufi, F.
A1 - Kasada, M.
A1 - Redouane, E. M.
A1 - Haida, M.
A1 - Aba, R. P.
A1 - Essadki, Y.
A1 - Zerrifi, S. E. A.
A1 - Herter, Sven-Oliver
A1 - Hejjaj, A.
A1 - Aziz, F.
A1 - Ouazzani, N.
A1 - Azevedo, J.
A1 - Campos, A.
A1 - Putschew, A.
A1 - Grossart, H.-P.
A1 - Mandi, L.
A1 - Vasconcelos, V.
A1 - Oudra, B.
T1 - Monitoring of toxic cyanobacterial blooms in Lalla Takerkoust reservoir by satellite imagery and microcystin transfer to surrounding farms
N2 - Cyanobacterial harmful algal blooms (CyanoHABs) threaten public health and freshwater ecosystems worldwide. In this study, our main goal was to explore the dynamics of cyanobacterial blooms and how microcystins (MCs) move from the Lalla Takerkoust reservoir to the nearby farms. We used Landsat imagery, molecular analysis, collecting and analyzing physicochemical data, and assessing toxins using HPLC. Our investigation identified two cyanobacterial species responsible for the blooms: Microcystis sp. and Synechococcus sp. Our Microcystis strain produced three MC variants (MC-RR, MC-YR, and MC-LR), with MC-RR exhibiting the highest concentrations in dissolved and intracellular toxins. In contrast, our Synechococcus strain did not produce any detectable toxins. To validate our Normalized Difference Vegetation Index (NDVI) results, we utilized limnological data, including algal cell counts, and quantified MCs in freeze-dried Microcystis bloom samples collected from the reservoir. Our study revealed patterns and trends in cyanobacterial proliferation in the reservoir over 30 years and presented a historical map of the area of cyanobacterial infestation using the NDVI method. The study found that MC-LR accumulates near the water surface due to the buoyancy of Microcystis. The maximum concentration of MC-LR in the reservoir water was 160 μg/L. In contrast, 4 km downstream of the reservoir, the concentration decreased by a factor of 5.39 to 29.63 μg/L, indicating a decrease in MC-LR concentration with increasing distance from the bloom source. Similarly, the MC-YR concentration decreased by a factor of 2.98 for the same distance. Interestingly, the MC distribution varied with depth, with MC-LR dominating at the water surface and MC-YR at the reservoir outlet at a water depth of 10 m. Our findings highlight the impact of nutrient concentrations, environmental factors, and transfer processes on bloom dynamics and MC distribution. We emphasize the need for effective management strategies to minimize toxin transfer and ensure public health and safety.
KW - Cyanotoxin
KW - HPLC-MS/MS
KW - Surface water
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623672
DO - https://doi.org/10.1016/j.hal.2024.102631
SN - 1568-9883
VL - 135
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - McGonigle, Rebecca
A1 - Glasgow, Jodie
A1 - Houston, Catriona
A1 - Cameron, Iain
A1 - Homann, Christian
A1 - Black, Dominic J.
A1 - Pal, Robert
A1 - MacKenzie, Lewis E.
ED - MacKenzie, Lewis E.
T1 - Autoclave reactor synthesis of upconversion nanoparticles, unreported variables, and safety considerations
N2 - Autoclave reactors are widely used across chemical and biological sciences, including for the synthesis of upconversion nanoparticles (UCNPs) and other nanomaterials. Yet, the details of how autoclave reactors are used in such synthesis are rarely reported in the literature, leaving several key synthesis variables widely unreported and thereby hampering experimental reproducibility. In this perspective, we discuss the safety considerations of autoclave reactors and note that autoclaves should only be used if they are (a) purchased from reputable suppliers/manufacturers and (b) have been certified compliant with relevant safety standards. Ultimately, using unsuitable autoclave equipment can pose a severe physical hazard and may breach legal safety requirements. In addition, we highlight several parameters in autoclave synthesis that should be reported as standard to maximise the reproducibility of autoclave synthesis experiments across materials and chemistry research. We encourage users of autoclave synthesis vessels to: (1) adopt high-safety autoclaves and (2) report the many experimental variables involved to enhance experimental reproducibility.
KW - Reference material
KW - Nano
KW - Particle
KW - Shell
KW - Fluorescence
KW - Lifetime
KW - Decay kinetics
KW - Synthesis
KW - Quality assurance
KW - Method
KW - Energy transfer
KW - Upconversion
KW - Autoclave synthesis
KW - Data comparability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625672
DO - https://doi.org/10.1038/s42004-025-01415-3
VL - 8
IS - 1
SP - 1
EP - 7
PB - Springer Science and Business Media LLC
AN - OPUS4-62567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rohrschneider, A.
A1 - Heckel, Thomas
A1 - Oelschlägel, T.
A1 - Schöll, M.
T1 - Innovative Optimierung der Ultraschallprüfung an Radsatzwellen
N2 - Betriebsbedingte Belastungen und eventuelle Oberflächenschädigungen einer Radsatzwelle können zu deren Versagen führen. Daher besteht die Notwendigkeit zur vorbeugenden Prüfung mit Hilfe zerstörungsfreier Prüfverfahren. Zurzeit setzt die Deutsche Bahn AG mechanisierte Ultraschall-Prüfsysteme (HPS-Anlagen) bei Radsatzwellen mit Längsbohrung ein. Die Prüfung erfolgt an den im Fahrzeug eingebauten Radsatzwellen. Diese Prüfanlagen nutzen feste Einschallwinkel. Die Nachweisempfindlichkeit liegt bei 2 mm tiefen Vergleichsfehlern für die Querfehlerprüfung. Zur Detektion der Querfehler werden positionsabhängige Blenden im A-Bild eingesetzt. Physikalisch bedingt können aber auch Unregelmäßigkeiten in der Beschichtung, aufgepresste Komponenten und andere Einflüsse zu einer Blendenüberschreitung und somit zu einer Befundung der Radsatzwelle führen. Die konventionelle Prüftechnik erlaubt dabei keine Unterscheidung zwischen diesen sogenannten Scheinanzeigen und den Querfehlern.
Ein Radsatztausch mit anschließender Demontage zur Ermittlung der Anzeigenursache ist in diesen Fällen daher derzeit unvermeidlich. Die von der DB Systemtechnik und Partnern untersuchte Phased-Array-Technik mit SAFT-Auswertealgorithmus (Synthetic Aperture Focussing Technique) soll helfen, die UT-Anzeigen besser bewerten zu können und den unnötigen Radsatzwechsel zu vermeiden. Das Ziel des UT-SAFT-Verfahrens ist es, die Tiefenkomponente von Rissen über das Rissspitzensignal zu detektieren und auswertbar zu machen. Durch eine nachgeschaltete UT-SAFT-Analyse soll an befundeten Radsatzwellen nachuntersucht werden, ob die Anzeigen der Reflektorpositionen innerhalb des Wellenvolumens, auf der Grenzfläche oder außerhalb des Wellenvolumens liegen.
Es wird erwartet, dass durch die zeitnahe Bestimmung der Anzeigenursache die erforderlichen Radsatzwechsel deutlich reduziert werden. Dadurch ist eine Erhöhung der Fahrzeugverfügbarkeit und eine Kostenreduzierung (Reduzierung des Aufwandes für Radsatzausbau, Radsatztransport, Nachprüfung und Aufarbeitung der Radsätze) erreichbar.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-286171
SN - 978-3-940283-49-8
IS - Mi.1.A.3
SP - 1
EP - 10
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28617
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poka, Konstantin
A1 - Ali, Sozol
A1 - Saeed, Waleed
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Quality assurance via a cyber physical system of a PBF-LB/M machine
N2 - Powder Bed Fusion with Laser Beam of Metals (PBF-LB/M) faces challenges in reproducibility and quality assurance, even for widely applied alloys like AlSi10Mg. This work introduces a digital provenance framework for PBF-LB/M, showcased through the EOS M 300–4 multi-laser machine. An Extract, Transform, Load (ETL) pipeline autonomously captures machine data, including scan vectors as well as process signals, and organizes them into a Digital Shadow (DS). The DS is further extended by external data sources, such as Melt Pool Monitoring (MPM), to enable comprehensive analysis and root cause identification. This approach ensures continuous data representation and facilitates the development of new quality metrics. Moreover, the framework enhances quality assurance and traceability, supports compliance with industry standards, and improves productivity. It also enables more precise cost calculations and predictive maintenance. By addressing these challenges, the framework is essential for advancing PBF-LB/M in industrial applications, achieving greater consistency and scalability in production.
KW - PBF-LB/M
KW - Data driven quality assurance
KW - Data engineering
KW - Digital shadow
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625187
DO - https://doi.org/10.1007/s40964-025-00978-w
SN - 2363-9520
VL - 10
IS - 3
SP - 1771
EP - 1783
PB - Springer Science and Business Media LLC
AN - OPUS4-62518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schackmann, Oliver
A1 - Márquez Reyes, Octavio A.
A1 - Memmolo, Vittorio
A1 - Lozano, Daniel
A1 - Prager, Jens
A1 - Moll, Jochen
A1 - Kraemer, Peter
T1 - Machine learning strategies with ensemble voting for ultrasonic damage detection in composite structures under varying temperature or load conditions
N2 - In recent years, the development of machine learning (ML) techniques has led to significant progress in the field of structural health monitoring with ultrasonic-guided waves. However, a number of challenges still need to be resolved for reliable operation in realistic settings. In this work, we consider the complex problem of experimental damage detection under varying temperature or load conditions where damage locations are not included in the training set. The ML techniques proposed here include supervised and unsupervised methods originally developed for image and time series classification combined with ensemble voting. A performance demonstration of the ML techniques is presented using benchmark datasets from the open-guided waves platform. The unsupervised approach is then applied to a new dataset from an experimental campaign carried out on a composite over-wrapped pressure vessel used for hydrogen storage with real defects. Results show that ensemble voting enables the effective combination of the predictions of multiple transducer pairs, even with a limited number of strong individual classifiers. When applied to unsupervised learning, this returns high accuracy also when real damage over the structure is considered.
KW - Structural-Health-Monitoring
KW - Ultrasonic guided waves
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631571
DO - https://doi.org/10.1177/14759217251333066
SN - 1741-3168
SP - 1
EP - 19
PB - Sage Publications
AN - OPUS4-63157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amano, Kofi Owusu Ansah
A1 - Tschirschwitz, Rico
A1 - Gimadieva, Elena
A1 - Köhler, Florian
A1 - Krause, Ulrich
T1 - Thermal runaway and explosibility of the gas release from 18650 sodium-ion cells of NFM chemistry
N2 - The present study investigates the thermal runaway behaviour and explosibility of the gas mixture released from sodium-ion batteries (SIBs). A total of 30 tests comprising two test series were performed using 18650 SIBs with a NaNi1/3Fe1/3Mn1/3O2 (NFM) chemistry. The cells of SOC level = 0 %, 25 %, 50 %, 75 % and 100 % were subjected to thermal abuse inside a 10 L pressurized reaction vessel. In test series 1, the tests were performed in an air atmosphere. In test series 2, an inert atmosphere was used. First, the total amount of gas released from the SIBs was calculated based on the temperature and pressure measured in the reaction vessel. Subsequently, a gas composition analysis was performed using a Fourier-transformed infrared (FTIR) spectrometer. This study revealed that the thermal runaway in SIBs could be categorized into four phases. At the onset of thermal runaway, the thermal runaway-induced explosion of the cells resulted in a rate of temperature rise ranging from 2 K/s to 70 K/s. The investigation further revealed a peak reaction temperature of 415 ◦C and a maximum pressure of 4 bar could be reached at thermal runaway in the 10 L vessel. The gas release of up to 5 ± 0.3 L (4 ± 0.2 L/Ah, 1.3 ± 0.1 L/Wh) from test series 1 and 2.4 ± 0.2 L (2 ± 0.1 L/Ah, 0.53 ± 0.04 L/Wh) from test series 2 showed a dependence on SOC and failure environment used. By applying Le Chatelier's mixing rule, the measured gas release from the air atmosphere showed a calculated lower explosion limit and upper explosion limit values of 4.8 % and 24 % in volume fraction, respectively.
KW - Sodium-ion battery
KW - Thermal runaway
KW - Gas release
KW - Gas explosion
KW - Explosion limit
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631782
DO - https://doi.org/10.1016/j.est.2025.116614
SN - 2352-152X
VL - 122
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-63178
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jafari, Abbas
A1 - Vlachas, K.
A1 - Chatzi, E.
A1 - Unger, Jörg F.
T1 - A Bayesian framework for constitutive model identification via use of full field measurements, with application to heterogeneous materials
N2 - In this paper, we present a Bayesian framework for the identification of the parameters of nonlinear constitutive material laws using full-field displacement measurements. The concept of force-based Finite Element Model Updating (FEMU-F) is employed, which relies on the availability of measurable quantities such as displacements and external forces. The proposed approach particularly unfolds the advantage of FEMU-F, as opposed to the conventional FEMU, by directly incorporating information from full-field measured displacements into the model. This feature is well-suited for heterogeneous materials with softening, where the localization zone depends on the random microstructure. Besides, to account for uncertainties in the measured displacements, we treat displacements as additional unknown variables to be identified, alongside the constitutive parameters. A variational Bayesian scheme is then employed to identify these unknowns via approximate posteriors under the assumption of multivariate normal distributions. An optimization problem is then formulated and solved iteratively, aiming to minimize the discrepancy between true and approximate posteriors. The benefit of the proposed approach lies in the stochastic nature of the formulation, which allows to tackle uncertainties related to model parameters and measurement noise. We verify the efficacy of our proposed framework on two simulated examples using gradient damage model with a path-dependent nonlinear constitutive law. Based on a nonlocal equivalent strain norm, this constitutive model can simulate a localized damage zone representing softening and cracking. The first example illustrates an application of the FEMU-F approach to cracked structures including sensitivity studies related to measurement noise and parameters of the prior distributions. In this example, the variational Bayesian solver demonstrates a sizable advantage in terms of computational efficiency compared to a traditional least-square optimizer. The second example demonstrates a sub-domain analysis to tackle challenges associated with limited domain knowledge such as uncertain boundary conditions.
KW - Constitutive model identification
KW - Full-field measurements
KW - Variational Bayes
KW - Force-based finite element model updating
KW - FEMU-F
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615476
DO - https://doi.org/10.1016/j.cma.2024.117489
SN - 1879-2138
VL - 433
IS - Part A
SP - 1
EP - 32
PB - Elsevier B.V.
AN - OPUS4-61547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Patrick
A1 - Helmrich, M.
A1 - Herrmann, Ralf
A1 - Schneider, Ronald
A1 - Baeßler, Matthias
A1 - Lorelli, S.
A1 - Morgenthal, G.
T1 - Maintalbrücke Gemünden: Bauwerksmonitoring und -identifikation aus einem Guss
T1 - Maintalbrücke Gemünden – Integrated structural health monitoring and UAS diagnostics
N2 - Die Infrastruktursysteme der Industriestaaten erfordern heute und in Zukunft ein effizientes Management bei alternder Bausubstanz, steigenden Lasten und gleichbleibend hohem Sicherheitsniveau. Digitale Technologien bieten ein großes Potenzial zur Bewältigung der aktuellen und künftigen Herausforderungen im Infrastrukturmanagement. Im BMBF-geförderten Projekt Bewertung alternder Infrastrukturbauwerke mit digitalen Technologien (AISTEC) wird untersucht, wie unterschiedliche Technologien und deren Verknüpfung gewinnbringend eingesetzt werden können. Am Beispiel der Maintalbrücke Gemünden werden ein sensorbasiertes Bauwerksmonitoring, bildbasierte Inspektion mit durch Kameras ausgestatteten Drohnen (UAS) und die Verknüpfung digitaler Bauwerksmodelle umgesetzt. Die aufgenommenen Bilder dienen u. a. als Grundlage für spätere visuelle Anomaliedetektionen und eine 3D-Rekonstruktion, welche wiederum für die Kalibrierung und Aktualisierung digitaler Tragwerksmodelle genutzt werden. Kontinuierlich erfasste Sensordaten werden ebenfalls zur Kalibrierung und Aktualisierung der Tragwerksmodelle herangezogen. Diese Modelle werden als Grundlage für Anomaliedetektionen und perspektivisch zur Umsetzung von Konzepten der prädiktiven Instandhaltung verwendet. Belastungsfahrten und historische Daten dienen in diesem Beitrag der Validierung von kalibrierten Tragwerksmodellen.
N2 - Infrastructure systems of industrialised countries today and in the future require efficient management with an ageing stock, increasing loads while simultaneously maintaining a high level of safety. Digital technologies offer great potential for the current and future challenges in infrastructure management. The BMBF-funded project AISTEC is investigating how the individual technologies and their interconnection can be used beneficially. With the Maintalbrücke in Gemünden as an exemplary application, sensor-based structural monitoring, image-based inspection using unmanned aircraft systems (UAS) equipped with cameras and the integration of digital structural models are being implemented. The recorded images serve, among others, as basis for subsequent anomaly detection and a 3D reconstruction, which in turn are used for updating digital structural models. Continuously recorded sensor data is used to update the parameters of the structural models, which in turn provide the basis for predictive maintenance. Load tests are used to validate the models.
KW - Bauwerksüberwachung
KW - Strukturmonitoring
KW - Structural Health Monitoring
KW - Modell-Update
KW - UAS
KW - Belastungstest
KW - Structural system identification
KW - Structural health monitoring
KW - Model update
KW - UAS
KW - Load tests
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554924
DO - https://doi.org/10.1002/bate.202100102
SN - 0932-8351
VL - 99
IS - 3
SP - 163
EP - 172
PB - Ernst & Sohn
CY - Berlin
AN - OPUS4-55492
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Ronald
A1 - Simon, Patrick
A1 - Hille, Falk
A1 - Herrmann, Ralf
A1 - Baeßler, Matthias
T1 - Vibration-based system identification of a large steel box girder bridge
N2 - The Bundesanstalt für Materialforschung und -prüfung (BAM) collaborates with TNO to develop a software framework for automated calibration of structural models based on monitoring data. The ultimate goal is to include such models in the asset management process of engineering structures. As a basis for developing the framework, a multi-span road bridge consisting of ten simply supported steel box girders was selected as a test case. Our group measured output-only vibration data from one box girder under ambient conditions. From the data, we determined eigenfrequencies and mode shapes. In parallel, we developed a preliminary structural model of the box girder for the purpose of predicting its modal properties. In this contribution, we provide an overview of the measurement campaign, the operational modal analysis, the structural modeling and qualitatively compare the identified with the predicted modes. As an outlook, we discuss the further steps in the calibration process and future applications of the calibrated model.
T2 - XII International Conference on Structural Dynamics (EURODYN 2023)
CY - Delft, The Netherlands
DA - 02.07.2023
KW - Verkehrsinfrastukturen
KW - SHM
KW - Model updating
KW - System identification
KW - Operational modal analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605041
DO - https://doi.org/10.1088/1742-6596/2647/18/182039
SN - 1742-6596
VL - 2647
IS - 18
SP - 1
EP - 9
PB - IOP Publishing
CY - Bristol
AN - OPUS4-60504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asna Ashari, Parsa
A1 - Blind, K.
A1 - Koch, Claudia
T1 - Knowledge and technology transfer via publications, patents, standards: Exploring the hydrogen technological innovation system
N2 - Clean technologies play a crucial role in reducing greenhouse gas emissions and protecting the climate. Hydrogen is a promising energy carrier and fuel that can be used in many applications. We explore the global hydrogen technological innovation system (TIS) by analyzing the three knowledge and technology transfer channels of publications, patents, and standards. Since the adoption of hydrogen technologies requires trust in their safety,this study specifically also focuses on hydrogen safety. Our results show that general and hydrogen safety research has increased significantly while patenting experienced stagnation. An analysis of the non-patent literature in safety patents shows little recognition of scientific publications. Similarly, publications are underrepresented in the analyzed 75 international hydrogen and fuel cell standards. This limited transfer of knowledge from published research to standards points to the necessity for greater involvement of researchers in standardization. We further derive implications for the hydrogen TIS and recommendations for a better and more impactful alignment of the three transfer channels.
KW - Technological innovation system
KW - Hydrogen safety
KW - Knowledge and technology transfer
KW - Publications
KW - Patents
KW - Standards
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564250
DO - https://doi.org/10.1016/j.techfore.2022.122201
SN - 0040-1625
VL - 187
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-56425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Vries, H.
A1 - Jacobs, K.
A1 - Egyedi, T.
A1 - Eto, M.
A1 - Fertig, S.
A1 - Kanevskaia, O.
A1 - Klintner, L.
A1 - Koch, Claudia
A1 - Mijatovic, I.
A1 - Mirtsch, Mona
A1 - Morone, P.
A1 - Orviska, M.
A1 - Riillo, C.
A1 - Scaramuzzino, G.
ED - Jacobs, K.
T1 - Standardization: Towards an agenda for research
N2 - Standardization research is a fairly new and is a still-evolving field of research, with possibly major practical ramifications. This article presents a summary of the authors’ subjective views of the most pressing research topics in the field. These include, among others, standards (e.g. incorporation of ethical issues), the potential impact of standards, the corporate management of standardization and legal issues like Intellectual Property Rights (IPR). In addition, gaps have been identified with a respect to a basic understanding of standardization, suggesting a need for better education in the field.
KW - EURAS
KW - Impact of standards
KW - Intellectual property rights (IPR)
KW - Research agenda
KW - Standardization research
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467873
DO - https://doi.org/10.4018/IJSR.2018010104
SN - 2470-8542
VL - 16
IS - 1
SP - 52
EP - 59
PB - IGI Global
AN - OPUS4-46787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirtsch, Mona
A1 - Blind, K.
A1 - Koch, Claudia
A1 - Dudek, Gabriele
T1 - Information security management in ICT and non-ICT sector companies: A preventive innovation perspective
N2 - Despite the growing dependence of companies on information technology and the increasingly negative impact of security incidents worldwide, there is little research on the management of information security at the company level. This paper seeks to expand knowledge on the implementation of an information security management system based on the widely used international standard ISO/IEC 27001. We present motives, experienced impacts, and obstacles related to ISO/IEC 27001 implementation using data from a survey of 125 ISO/IEC 27001 certified companies in Germany. Since adoption rates vary between ICT and non-ICT sector companies, we highlight sector-related variations. We classify the adoption of this standard as a preventive organizational innovation and apply Structural Equation Modeling to unearth explanations for the comparatively low adoption of this management system standard among companies outside the ICT sector. We, therefore, derive recommendations for policymakers, standardization, and certification bodies to foster its diffusion.
KW - Information Security
KW - ISO/IEC 27001
KW - Management system standard
KW - Certification
KW - Information security management system (ISMS)
KW - Preventive Innovation
KW - Resource-based-view
KW - Institutional theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531037
DO - https://doi.org/10.1016/j.cose.2021.102383
SN - 0167-4048
VL - 109
IS - 10
SP - 1
EP - 23
PB - Elsevier Ltd.
AN - OPUS4-53103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlegel, Moritz-Caspar
A1 - Koch, Claudia
A1 - Mirtsch, Mona
A1 - Harrer, Andrea
T1 - Smart Products Enable Smart Regulations—Optimal Durability Requirements Facilitated by the IoT
N2 - The challenges and opportunities linked with IoT have been intensively discussed in recent years. The connectivity of things over their entire life cycle and the smart properties associated with it provide new functionalities and unprecedented availability of (usage) data. This offers huge opportunities for manufacturers, service providers, users, and also policymakers. The latter May impact policy areas such as the regulations on resource and materials efficiency under the Ecodesign Directive 2009/125/EC. With the general approach as it is practiced today, legal requirements are usually set for entire product groups without considering the products individually, including user behavior and environmental conditions. The increasing number of smart products and the growing availability of product data are sparking a discussion on whether these requirements could be more product and application-specific. This paper presents a method for calculating the economically and ecologically optimal durability of a product. It allows determining the point in time when a product should be replaced by combining consumer data with product design data. This novel Approach could contribute to making product regulation more flexible and possibly more efficient. In this context, fundamental challenges associated with smart products in policymaking are also discussed.
KW - Ecodesign
KW - Internet of Things
KW - Connectivity
KW - Resource efficiency
KW - Policy making
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524924
DO - https://doi.org/10.3390/su13084395
VL - 13
IS - 8
SP - 4395
PB - MDPI
CY - Basel
AN - OPUS4-52492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koch, Claudia
A1 - Asna Ashari, Parsa
A1 - Mirtsch, Mona
A1 - Blind, K.
A1 - Castka, P.
T1 - Impact of the COVID-19 pandemic on accredited conformity assessment bodies: insights from a multinational study
N2 - The COVID-19 pandemic posed new and manifold challenges to organizations and their operations worldwide. Conformity assessment bodies (CABs), such as testing or medical laboratories, certification, and inspection bodies, were also affected by the associated disruptions. Their role in this crisis is highly relevant, as CABs are essential pillars of the quality infrastructure: their activities ensure that products and services meet requirements as defined in standards and regulations, thereby contributing to their safety and reliability. The question arises of how CABs and their operations were affected by the pandemic and how they responded. To this end, we present the results of an international survey of 986 CABs of all types in Germany, the UK, Italy, and New Zealand. Overall, CABs reported, on average, a reduction in demand for their services during the pandemic, facing restrictions in all countries. In addition, the pandemic had an overall negative impact on the CABs’ investment and innovation activities. However, investments in digital infrastructure were increased as a countermeasure, with CABs reporting a higher need for digitalization. The paper highlights and discusses results from in-depth analyses relevant to policymakers and industry alike.
KW - Quality Infrastructure
KW - Digitalization
KW - Testing laboratories
KW - Conformity assessment
KW - Certification
KW - Conformity assessment body
KW - Corona
KW - Covid-19
KW - Resilience
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556396
DO - https://doi.org/10.1007/s00769-022-01514-x
SP - 1
EP - 14
PB - Springer
AN - OPUS4-55639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Simkin, Roman
T1 - Identifying the initial corrosion fatigue failure based on dropping electrochemical potential
N2 - The corrosion fatigue of duplex stainless-steel X2CrNiMoN22-5-3 can be determined by purely alternating axial cyclic load to failure using hour-glass shaped specimens. The experimental setup comprises a corrosion chamber allowing for the circulation of an aquifer electrolyte heated to 369 K simulating a carbon capture and storage as well as geothermal power plant environment. During engineering of a carbon storage site or geothermal power plant, it may be crucial to determine the failure onset of a component beforehand. Therefore, an algorithm with 93.3% reliability was established based on splitting the measured potential values into ten time series with a capacity of ten values. The failure of corrosion fatigue specimens in a geothermal environment correlates to the drop of the curves of the electrochemical potential which is measured simultaneously within the corrosion chamber. Crack initiation was, therefore, successfully derived from the electrochemical potential.
KW - Corrosion fatigue
KW - Surface corrosion
KW - CO2
KW - Crack initiation
KW - Geothermal energy production
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629310
DO - https://doi.org/10.3390/app15010403
SN - 2076-3417
VL - 15
IS - 1
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-62931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haapalehto, Matias
A1 - Pinomaa, Tatu
A1 - Wang, Lei
A1 - Laukkanen, Anssi
T1 - An atomistic simulation study of rapid solidification kinetics and crystal defects in dilute Al–Cu alloys
N2 - Rapid solidification kinetics of dilute Al–Cu alloys is simulated using a quantum mechanics based bondorder potential (BOP), in free solidification conditions, to determine kinetic and thermodynamic properties of solidification, as well as point defects and chemical ordering of the solidified structures. We measure the anisotropic kinetic coefficient, anisotropic solid–liquid interface energy, as well as solute trapping kinetics in terms of partition coefficient versus velocity and solute drag coefficient. Furthermore, solid–liquid interface free energy and its anisotropy are measured in equilibrium simulations, showing reasonably good agreement with previous studies. We also verified the self-consistency of the MD simulations, by comparing the interfacial temperature vs. velocity to that predicted by the continuous growth model. These solid–liquid interface properties are important for quantitative parametrization of larger scale solidification modeling techniques such as phase field models. We also investigated the point defect content, local chemical ordering, and local crystalline structures in the rapidly solidified samples. We found clustering of solute with vacancies, whereas copper atoms repelled each other in these dilute alloy simulations. In addition to vacancies, a large number of interstitials were found. In solidification velocities approaching the complete solute trapping regime, we found that the vacancies and interstitials formed in conjunction, i.e. as Frenkel pairs. Finally, in addition to FCC, we detected BCC and HCP phases, where the latter two were accompanied by an increase in local copper content. Understanding the formation of point defects and their relationship to chemical ordering is an important step towards controlling the formation of pre-precipitates and precipitates, which are an important strengthening mechanism for aluminum–copper alloys.
KW - Rapid solidification
KW - Aluminum–copper
KW - MD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628722
DO - https://doi.org/10.1016/j.commatsci.2022.111356
SN - 0927-0256
VL - 209
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kumar, Sumit
A1 - Swaminathan, Srinivasan
A1 - Hesse, Rene
A1 - Goldbeck, Hennig
A1 - Ding, Wenjin
A1 - Bonk, Alexander
A1 - Bauer, Thomas
T1 - Understanding the effect of oxide ions on Solar Salt chemistry and corrosion mechanism of 316L stainless steel at 600 °C
N2 - Solar Salt (60 wt% NaNO3, 40 wt% KNO3), used in Concentrated Solar Power (CSP) Thermal Energy Storage (TES) technology, can decompose into various products at elevated temperatures, with oxide ions being one of the known corrosive byproducts. The study mimics Solar Salt aging by intentionally adding sodium peroxide (Na2O2) and sodium oxide (Na2O) at concentrations of 0.005–0.33 wt% to investigate their role in the corrosion of austenitic stainless steel at 600 °C in typical operating conditions. Salt chemistry (nitrite, nitrate, oxide ions, and metal cations) was analyzed every 24 h, and steel corrosion after 168 h was assessed by weight change, corrosion rate, phase analysis, and cross-sectional morphology. Results reveal that at or above 0.135 wt% added Na2O2/Na2O leads to a quasi-steady-state equilibrium of oxide ions in the salt. Interestingly, at these concentrations, the presence of steel further decreases oxide ion concentration. Furthermore, above 0.135 wt%, the corrosion rate increases significantly, along with increased spallation, porosity and disintegration of the corrosion layer, forming a non-protective layer. This study highlights the critical role of oxide ions in the corrosion process.
KW - Solar Salt
KW - High temperature corrosion
KW - Thermal Energy Storage
KW - Alkali oxides
KW - Austenitic stainless steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628463
DO - https://doi.org/10.1016/j.corsci.2025.112849
SN - 1879-0496
VL - 249
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-62846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fiedler, Saskia
A1 - Ton-That, C.
A1 - Phillips, M. R.
T1 - Defect-free ZnO nanorods with high angular distribution for enhanced excitonic emission
N2 - AbstractLow-temperature hydrothermal growth has emerged as a popular method for the fabrication of ZnO nanorods (NRs), increasing the functionality and utility of ZnO-based devices. In this work, we study the influence of growth time, temperature and seed layer on the dimensions and angular distribution of ZnO NRs. High-quality NRs with a crisscrossed 60° angular distribution have been grown with a 20–60 nm diameter and 600 nm length. We show that, within the ideal range of growth parameters, the growth time and temperature have no controllable influence on NR diameter and length, while the deposition method and size of the pre-growth deposited ZnO seeds affects diameter and NR angular alignment. We demonstrate advantages of using crisscross-aligned NRs over planar ZnO for the enhancement of ZnO excitonic emission by optical coupling with gold nanoparticles. These results can be readily adapted for applications that involve surface coating-mediated enhancement of both light emission and injection.
KW - ZnO nanorod
KW - Hydrothermal growth
KW - Seed layer
KW - Angular distribution
KW - Cathodoluminescence
KW - Luminescence enhancement
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618176
DO - https://doi.org/10.1557/s43578-023-00941-x
SN - 0884-2914
SN - 2044-5326
VL - 38
IS - 8
SP - 2145
EP - 2155
PB - Springer
CY - Berlin
AN - OPUS4-61817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schardt, Annika
A1 - Schmitt, Johannes
A1 - Engelhard, Carsten
T1 - Single particle inductively coupled plasma mass spectrometry with nanosecond time resolution
N2 - In this proof-of-principle study, we present our contribution to single particle inductively coupled plasma mass spectrometry (spICP-MS) developments with a novel in-house built data acquisition system with nanosecond time resolution (nanoDAQ) and a matching data processing approach. The new system can continuously sample the secondary electron multiplier (SEM) detector signal and enables the detection of gold nanoparticles (AuNP) as small as 7.5 nm with the commercial single quadrupole ICP-MS instrument used in this study. Recording of the SEM signal by the nanoDAQ is performed with a dwell time of approximately 4 ns. A tailored method was developed to process this type of transient data, which is based on determining the temporal distance between detector events that is denoted as event gap (EG). We found that the inverse logarithm of EG is proportional to the particle size and that the number of detector events corresponding to a particle signal distribution can be used to calibrate and determine the particle number concentration (PNC) of a nanoparticle dispersion. Due to the high data acquisition frequency, a statistically significant number of data points can be obtained in 60 s or less and the main time limitation for analyses is merely the sample uptake time and rinsing step between analyte solutions. At this stage, the data processing method provides average information on complete data sets only and will be adapted to enable particle-by-particle analysis with future hardware/software revision.
KW - ICP-MS
KW - Nanoparticles
KW - Nanosecond time resolution
KW - Single particle detection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612706
DO - https://doi.org/10.1039/d3ja00373f
SN - 1364-5544
SN - 0267-9477
VL - 39
IS - 2
SP - 389
EP - 400
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-61270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fosodeder, P.
A1 - Baumgartner, W.
A1 - Steinwender, C.
A1 - Hassel, A. W.
A1 - Florian, Camilo
A1 - Bonse, Jörn
A1 - Heitz, J.
T1 - Repellent rings at titanium cylinders against overgrowth by fibroblasts
N2 - The invention of new miniaturized and smart medical implants continues in all medical fields, including miniaturized heart pacemakers. These implants often come with a titanium (Ti) casing, which may have to be removed after several months or years and shall therefore not be completely overgrown by cells or scar tissue after implantation. Scar tissue is mainly formed by fibroblast cells and extracellular matrix proteins like collagen produced by them. Suppression of fibroblast growth at Ti surfaces could be achieved by 800 nm femtosecond laser-ablation creating self-organized sharp spikes with dimensions in the 10 μm-range which are superposed by fine sub-μm parallel ripples. On flat Ti control samples, the best results regarding suppression of cell growth were obtained on spike-structures which were additionally electrochemically anodized under acidic conditions. When Ti cylinders with a diameter of 8 mm (similar as the pacemakers) were placed upright in a culture of murine fibroblasts, a multi-layer cell growth up to a height of at least 1.5 mm occurred within 19–22 days. We have demonstrated that a laser-structured and anodized ring around the Ti cylinder surface is an effective way to create a barrier that murine fibroblasts were not able to overgrow within this time.
KW - Cell-repellent surfaces
KW - Femtosecond laser-processing
KW - Electrochemical treatment
KW - Laser-induced micro- and nanostructures
KW - Medical implants
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509966
DO - https://doi.org/10.1515/aot-2019-0070
SN - 2193-8576
SN - 2193-8584
VL - 9
IS - 3 (Topical issue: Laser micro- and nano-material processing - Part 2)
SP - 113
EP - 120
PB - De Gruyter
CY - Berlin
AN - OPUS4-50996
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hille, Falk
A1 - Sowietzki, D.
A1 - Makris, R.
T1 - Luminescence-based early detection of fatigue cracks
N2 - Classic non-destructive fatigue crack detection methods reveal the state of the fatigue damage evolution at the moment of application, generally not under operational conditions. The here introduced crack luminescence method realizes a clear visibility of the occurred and growing crack in loaded components during operation. Different established experiments show that due to the sensitive coating a crack Formation can be detected even in early stage under the premise the crack reached the surface. The coating consists of two layers with different properties and functions. The bottom layer emits light as fluorescence under UV radiation. The top layer covers the fluorescing one and prevents the emitting of light in case of no damage at the surface. In case of surface crack occurrence, the luminescent light is clearly noticeable by visual observations and also by standard camera equipment which makes automated crack detection possible as well. It is expected that crack luminescence can increase structural safety as well as reduce costs and time for inspections and preventive maintenance.
KW - Coating
KW - Fatigue
KW - Crack damage detection
KW - Luminescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510517
DO - https://doi.org/10.1016/j.matpr.2020.02.338
SN - 2214-7853
SP - 1
EP - 5
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Esmann, M.
A1 - Chimeh, A.
A1 - Korte, A.
A1 - Zhong, J.
A1 - Stephan, S.
A1 - Witt, Julia
A1 - Wittstock, G.
A1 - Talebi, N.
A1 - Lienau, C.
T1 - Plasmonic nanofocusing spectral interferometry
N2 - We describe and demonstrate a novel experimental approach to measure broadband, amplitude- and phase-resolved scattering spectra of single nanoparticles with 10-nm spatial resolution. Nanofocusing of Surface plasmon polaritons (SPPs) propagating along the shaft of a conical gold taper is used to create a spatially isolated, spectrally broad nanoscale light source at ist very apex. The interference between these incident SPPs and SPPs that are backpropagating from the apex leads to the formation of an inherently phase-stable interferogram, which we detect in the far field by partially scattering SPPs off a small protrusion on the taper shaft. We show that these interferograms allow the reconstruction of both the amplitude and phase of the local optical near fields around individual nanoparticles optically coupled to the taper apex. We extract local light scattering spectra of particles and quantify line broadenings and spectral shifts induced by tip-sample coupling. Our experimental findings are supported by corresponding finite-difference time-domain and coupled dipole simulations and Show that, in the limit of weak tip-sample coupling, the measurements directly probe the projected local density of optical states of the plasmonic system. The combination of a highly stable inline interferometer with the inherent optical background suppression through nanofocusing makes it a promising tool for the locally resolved study of the spectral and temporal optical response of coupled hybrid nanosystems.
KW - Plasmonic nanofocusing
KW - Near-field spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504985
DO - https://doi.org/10.1515/nanoph-2019-0397
VL - 9
IS - 2
SP - 491
EP - 508
PB - De Gruyter
AN - OPUS4-50498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
T1 - Study of micro- and nanoscale wetting properties of lubricants using AFM force-distance curves
N2 - Atomic force microscopy (AFM) plays an important role as a multifuntional tool in nanotribology.In the present work it was shown that the main features of force-distance curves on different lubricants have been characterized and the underlying phenomena could be explained.
KW - Lubricants
KW - Atomic force microscopy
KW - Force-distance curves
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504631
DO - https://doi.org/10.1007/s11249-020-1275-3
SN - 1573-2711
VL - 68
IS - 1
SP - 1
EP - 12
PB - Springer
CY - Cham
AN - OPUS4-50463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
T1 - Editorial: Special issue "Laser-induced periodic surface nano- and microstructures for tribological applications"
N2 - Laser material processing is an emerging technology that generates surface functionalities on the basis of optical, mechanical, or chemical properties. In the form of laser surface texturing (LST), it has attracted a remarkable amount of research to tailor surface properties towards various tribological applications. The main advantages of this single-step, laser-based technology are the contactless machining, featuring a high flexibility, efficiency, and speed, along with the excellent quality of the processed products. LST can be applied precisely localized to sub-micrometric areas, but, via laser beam scanning, it is also feasible for structuring large surface areas at the square meter size.
This Special Issue focuses on the latest developments concerning the tribological performance of laser-generated periodic surface nano- and microstructures and their applications. This includes the laser-based processing of different surface patterns, such as “self-organized” laser-induced periodic surface structures (LIPSS, ripples), grooves, micro-spikes, hierarchical hybrid nano-/micro-structures, microfeatures generated by direct laser interference patterning (DLIP), or even dimples or other topographic geometries shaped by direct laser modification or ablation. The applications of these periodically nano- and micro-patterned surfaces may improve the lubricated or non-lubricated tribological performance of surfaces in conformal and even non-conformal contact through a reduction of wear, a variation of the coefficient of friction, altered load carrying capacity, etc., resulting in energy saving, improved reliability, increased lifetimes as well as durability, leading in turn to extended maintenance intervals/reduced down-time. This can be beneficial in terms of bearings, gears, engines, seals, cutting tools, or other tribological components. Fundamental aspects addressed may involve the investigation of the relevant physical and chemical effects accompanying the laser-generated nano- and microscale topographies, such as alterations of the material structures, the hardness, superficial oxidation, the role of additives contained in lubricants, surface wettability, micro-hydrodynamic effects, etc.
For this Special Issue we aim to attract both academic and industrial researchers and would like to provide a bridge between research in the fields of tribology and laser material processing in order to foster the current knowledge and present new ideas for future applications and new technologies.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Tribology
KW - Applications
KW - Wear
KW - Friction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505948
DO - https://doi.org/10.3390/lubricants8030034
SN - 2075-4442
VL - 8
IS - 3
SP - 34, 1
EP - 34, 3
PB - MDPI
CY - Basel
AN - OPUS4-50594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dub, S.
A1 - Haftaoglu, Cetin
A1 - Kindrachuk, Vitaliy
T1 - Estimate of theoretical shear strength of C60 single crystal by nanoindentation
N2 - The onset of plasticity in a single crystal C60 fullerite was investigated by nanoindentation on the (111) crystallographic plane. The transition from elastic to plastic deformation in a contact was observed as pop-in events on loading curves. The respective resolved shear stresses were computed for the octahedral slip systems ⟨011¯¯¯⟩{111}, supposing that their activation resulted in the onset of plasticity. A finite element analysis was applied, which reproduced the elastic loading until the first pop-in, using a realistic geometry of the Berkovich indenter blunt tip. The obtained estimate of the C60 theoretical shear strength was about 1/11 of the shear modulus on {111} planes.
KW - Finite element analysis
KW - Fullerite
KW - Nanoindentation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523208
DO - https://doi.org/10.1007/s10853-021-05991-2
VL - 56
IS - 18
SP - 10905
EP - 10914
PB - Springer Nature
AN - OPUS4-52320
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Wolf, M.
A1 - Kranzmann, Axel
T1 - Corrosion and Corrosion Fatigue of Steels in Downhole CCS Environment—A Summary
N2 - Static immersion tests of potential injection pipe steels 42CrMo4, X20Cr13, X46Cr13, X35CrMo4, and X5CrNiCuNb16-4 at T = 60°C and ambient pressure, as well as p = 100 bar were performed for 700–8000 h in a CO2-saturated synthetic aquifer environment similar to CCS sites in the Northern German Basin (NGB). Corrosion rates at 100 bar are generally lower than at ambient pressure. The main corrosion products are FeCO3 and FeOOH with surface and local corrosion phenomena directly related to the alloy composition and microstructure. The appropriate heat treatment enhances corrosion resistance. The lifetime reduction of X46Cr13, X5CrNiCuNb16-4, and duplex stainless steel X2CrNiMoN22-5-3 in a CCS environment is demonstrated in the in situ corrosion fatigue CF experiments (axial push-pull and rotation bending load, 60°C , brine: Stuttgart Aquifer and NGB, flowing CO2: 30 L/h, +/- applied potential). Insulating the test setup is necessary to gain reliable data. S-N plots, micrographic-, phase-, fractographic-, and surface analysis prove that the life expectancy of X2CrNiMoN22-5-3 in the axial cyclic load to failure is clearly related to the surface finish, applied stress amplitude, and stress mode. The horizontal grain attack within corrosion pit cavities, multiple fatigue cracks, and preferable deterioration of austenitic phase mainly cause fatigue failure. The CF life range increases significantly when a protective potential is applied.
KW - Carbon capture and storage
KW - Steel
KW - High alloyed steel
KW - Corrosion
KW - Corrosion fatigue
KW - CCS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523948
DO - https://doi.org/10.3390/pr9040594
VL - 9
IS - 4
SP - 594
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfretzschner, Beate
A1 - Schaupp, Thomas
A1 - Hannemann, Andreas
A1 - Schultz, Michael
A1 - Griesche, Axel
T1 - On the Genesis of Artifacts in Neutron Transmission Imaging of Hydrogenous Steel Specimens
N2 - Hydrogen-charged supermartensitic steel samples were used to systematically investigate imaging artifacts in neutron radiography. Cadmium stencils were placed around the samples to shield the scintillator from excessive neutron radiation and to investigate the influence of the backlight effect. The contribution of scattered neutrons to the total detected intensity was investigated by additionally varying the sample-detector distance and applying a functional correlation between distance and intensity. Furthermore, the influence of the surface roughness on the edge effect due to refraction was investigated.
KW - Refraction
KW - Neutron imaging
KW - Hydrogen
KW - Supermartensitic steel
KW - Backlight
KW - Scattering
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506587
DO - https://doi.org/10.3390/jimaging6040022
VL - 6
IS - 22
SP - 1
EP - 10
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50658
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Khandarkhaeva, S.
A1 - Bykov, M.
A1 - Fedotenko, T.
A1 - Hanfland, M.
A1 - Sukhikh, A.
A1 - Gromilov, S.
A1 - Dubrovinsky, L.
T1 - Face-centered cubic refractory alloys prepared from single-source precursors
N2 - Three binary fcc-structured alloys (fcc–Ir0.50Pt0.50, fcc Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50) were 14 prepared from [Ir(NH3)5Cl][PtCl6], [Ir(NH3)5Cl][PtBr6], [Rh(NH3)5Cl]2[PtCl6]Cl2 and 15 [Rh(NH3)5Cl][PdCl4]·H2O, respectively, as single-source precursors. All alloys were prepared by 16 thermal decomposition in gaseous hydrogen flow below 800 °C. Fcc–Ir0.50Pt0.50 and fcc–Rh0.50Pd0.50 17 correspond to miscibility gaps on binary metallic phase diagrams and can be considered as 18 metastable alloys. Detailed comparison of [Ir(NH3)5Cl][PtCl6] and [Ir(NH3)5Cl][PtBr6] crystal 19 structures suggests that two isoformular salts are not isostructural. In [Ir(NH3)5Cl][PtBr6], specific 20 Br…Br interactions are responsible for crystal structure arrangement. Room temperature 21 compressibility of fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50 has been investigated up to 50 GPa 22 in diamond anvil cells. All investigated fcc-structured binary alloys are stable under compression. 23 Atomic volumes and bulk moduli show good agreement with ideal solutions model. For fcc–24 Ir0.50Pt0.50, V0/Z = 14.597(6) Å3·atom-1, B0 = 321(6) GPa, B0' = 6(1); for fcc–Rh0.66Pt0.33, V0/Z = 14.211(3) 25 Å3·atom-1, B0 =259(1) GPa, B0' = 6.66(9); for fcc–Rh0.50Pd0.50, V0/Z = 14.18(2) Å3·atom-1, B0 =223(4) GPa, 26 B0' = 5.0(3).
KW - High-pressure
KW - Refractory alloys
KW - Platinum group metals
KW - Single-source precursors
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508176
DO - https://doi.org/10.3390/ma13061418
VL - 13
IS - 6
SP - 1418
PB - MDPI
CY - Basel
AN - OPUS4-50817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Sukhikh, A.
A1 - Kraus, Werner
A1 - Gromilov, S.
T1 - Synthesis and Crystal Chemistry of Octahedral Rhodium(III) Chloroamines
N2 - Rhodium(III) octahedral complexes with amine and chloride ligands are the most common starting compounds for preparing catalytically active rhodium(I) and rhodium(III) species. Despite intensive study during the last 100 years, synthesis and crystal structures of rhodium(III) complexes were described only briefly. Some [RhClx(NH3)6-x] compounds are still unknown. In this study, available information about synthetic protocols and the crystal structures of possible [RhClx(NH3)6−x] octahedral species are summarized and critically analyzed. Unknown crystal structuresof(NH4)2[Rh(NH3)Cl5],trans–[Rh(NH3)4Cl2]Cl·H2O,andcis–[Rh(NH3)4Cl2]Clarereported based on high quality single crystal X-ray diffraction data. The crystal structure of [Rh(NH3)5Cl]Cl2 was redetermined. All available crystal structures with octahedral complexes [RhClx(NH3)6-x] were analyzed in terms of their packings and pseudo-translational sublattices. Pseudo-translation lattices suggest face-centered cubic and hexagonal closed-packed sub-cells, where Rh atoms occupy nearly ideal lattices.
KW - Pseudo-translationalsublattices
KW - Rhodiumcomplexes
KW - Ligandsubstitution
KW - Crystalstructure
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508194
DO - https://doi.org/10.3390/molecules25040768
VL - 25
IS - 4
SP - 768
PB - MDPI
CY - Basel
AN - OPUS4-50819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Domonov, D.
A1 - Pechenyuk, S.
A1 - Belyevskii, A.
T1 - Formation of Nanostructured Carbon from [Ni(NH3)6]3[Fe(CN)6]2
N2 - The products of thermal decomposition in an argon atmosphere of [Ni(NH3)6]3[Fe(CN)6]2 as a precursor has been studied. Decomposition products were studied up to 800◦C. Above 600◦C, all coordination bonds in the residues are broken with a formation of Ni3Fe, Fe, and free carbon with a small admixture of nitrogen. Elementary carbon can be easily separated from metals by treatment with a water solution of hydrochloric acid. Only carbon is responsible for the specific surface of the composite products. The released carbon has a high degree of graphitization and begins to oxidize in air above 500°C and is completely oxidized above 700°C.
KW - Carbon materials
KW - Double complex compound
KW - Thermal decomposition
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508188
DO - https://doi.org/10.3390/nano10020389
VL - 10
IS - 2
SP - 389
PB - MDPI
CY - Basel
AN - OPUS4-50818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrand, G.
A1 - Sänger, Johanna Christiane
A1 - Schirmer, U.
A1 - Mantei, W.
A1 - Dupuis, Y.
A1 - Houbertz, R.
A1 - Liefeith, K.
T1 - Process Development for Additive Manufacturing of Alumina Toughened Zirconia for 3D Structures by Means of Two-Photon Absorption Technique
N2 - Additive manufacturing is well established for plastics and metals, and it gets more and more implemented in a variety of industrial processes. Beside these well-established material platforms, additive manufacturing processes are highly interesting for ceramics, especially regarding resource conservation and for the production of complex three-dimensional shapes and structures with specific feature sizes in the µm and mm range with high accuracy. The usage of ceramics in 3D printing is, however, just at the beginning of a technical implementation in a continuously and fast rising field of research and development. The flexible fabrication of highly complex and precise 3D structures by means of light-induced photopolymerization that are difficult to realize using traditional ceramic fabrication methods such as casting and machining is of high importance. Generally, slurry-based ceramic 3D printing technologies involve liquid or semi-liquid polymeric systems dispersed with ceramic particles as feedstock (inks or pastes), depending on the solid loading and viscosity of the system. This paper includes all types of photo-curable polymer-ceramic-mixtures (feedstock), while demonstrating our own work on 3D printed alumina toughened zirconia based ceramic slurries with light induced polymerization on the basis of two-photon absorption (TPA) for the first time. As a proven exemplary on cuboids with varying edge length and double pyramids in the µm-range we state that real 3D micro-stereolithographic fabrication of ceramic products will be generally possible in the near future by means of TPA. This technology enables the fabrication of 3D structures with high accuracy in comparison to ceramic technologies that apply single-photon excitation. In sum, our work is intended to contribute to the fundamental development of this technology for the representation of oxide-ceramic components (proof-of-principle) and helps to exploit the high potential of additive processes in the field of bio-ceramics in the medium to long-term future.
KW - Additive manufacturing
KW - Ceramics 3D printing
KW - Two-photon adsorption
KW - Polymer-ceramic mixtures
KW - Bio-ceramic engineering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526672
DO - https://doi.org/10.3390/ceramics4020017
VL - 4
IS - 2
SP - 224
EP - 239
PB - MDPI
CY - Basel
AN - OPUS4-52667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan-Scherb, Christiane
A1 - Schulz, Wencke
A1 - Schneider, M.
A1 - Karafiludis, Stephanos
A1 - Laplanche, G.
T1 - High-Temperature Oxidation in Dry and Humid Atmospheres of the Equiatomic CrMnFeCoNi and CrCoNi High- and Medium-Entropy Alloys
N2 - Surface degradation phenomena of two model equiatomic alloys from the CrMnFeCoNi alloy system were investigated in 2% O2 and 10% H2O (pO2 = 0.02 and 10−7 atm, respectively) at 800 °C for times up to 96 h. The crystallographic structures, morphologies, and chemical compositions of the corrosion layers developing on CrMnFeCoNi and CrCoNi were comparatively analyzed by mass gain analysis, X-ray diffraction, and scanning electron microscopy combined with energy-dispersive X-ray spectroscopy and electron backscatter diffraction. The oxidation resistance of CrMnFeCoNi is relatively poor due to the fast growth of porous Mnoxide(s). CrCoNi forms an external chromia layer that is dense and continuous in a dry 2% O2 atmosphere. This layer buckles and spalls off after exposure to 10% H2O atmosphere. Beneath the chromia layer, a Cr-depleted zone forms in the CrCoNi alloy in both environments. As the oxide scale spalls off in the H2O-containing
atmosphere, a secondary chromia layer was observed and correspondingly enlarges the Cr-depleted zone. In contrast, as the chromia layer remains without significant spallation when CrCoNi is exposed to a dry oxidizing atmosphere, the region depleted in Cr is narrower.
KW - High temperature oxidation
KW - High entropy alloys
KW - Medium entropy alloys
KW - CrMnFeCoNi
KW - CrCoNi
KW - Mn-oxides
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517859
DO - https://doi.org/10.1007/s11085-020-10014-7
SN - 0030-770X
VL - 95
IS - 1-2
SP - 105
EP - 133
PB - Springer
AN - OPUS4-51785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santos, C.I.L.
A1 - Machado, W.S.
A1 - Wegner, Karl David
A1 - Gontijo, L.A.P.
A1 - Bettini, J.
A1 - Schiavon, M.A.
A1 - Reiss, P.
A1 - Aldakov, D.
T1 - Hydrothermal Synthesis of Aqueous-Soluble Copper Indium Sulfide Nanocrystals and Their Use in Quantum Dot Sensitized Solar Cells
N2 - facile hydrothermal method to synthesize water-soluble copper indium sulfide (CIS) nanocrystals (NCs) at 150 degrees C is presented. The obtained samples exhibited three distinct photoluminescence peaks in the red, green and blue spectral regions, corresponding to three size fractions, which could be separated by means of size-selective precipitation. While the red and green emitting fractions consist of 4.5 and 2.5 nm CIS NCs, the blue fraction was identified as in situ formed carbon nanodots showing excitation wavelength dependent emission. When used as light absorbers in quantum dot sensitized solar cells, the individual green and red fractions yielded power conversion efficiencies of 2.9% and 2.6%, respectively. With the unfractionated samples, the efficiency values approaching 5% were obtained. This improvement was mainly due to a significantly enhanced photocurrent arising from complementary panchromatic absorption.
KW - Aqueous quantum dot
KW - Solar cells
KW - CUINS2 nanocrystals
KW - Colloidal semiconductor nanocrystals
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517983
DO - https://doi.org/10.3390/nano10071252
VL - 10
IS - 7
SP - 1252
PB - MDPI
AN - OPUS4-51798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cubero, A.
A1 - Martínez, E.
A1 - Angurel, L.A.
A1 - de la Fuente, G.F.
A1 - Navarro, R.
A1 - Legall, Herbert
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Surface superconductivity changes of niobium sheets by femtosecond laser-induced periodic nanostructures
N2 - Irradiation with ultra-short (femtosecond) laser beams enables the generation of sub-wavelength laser-induced periodic surface structures (LIPSS) over large areas with controlled spatial periodicity, orientation, and depths affecting only a material layer on the sub-micrometer scale. This study reports on how fs-laser irradiation of commercially available Nb foil samples affects their superconducting behavior. DC magnetization and AC susceptibility measurements at cryogenic temperatures and with magnetic fields of different amplitude and orientation are thus analyzed and reported. This study pays special attention to the surface superconducting layer that persists above the upper critical magnetic field strength Hc2, and disappears at a higher nucleation field strength Hc3. Characteristic changes were distinguished between the surface properties of the laser-irradiated samples, as compared to the corresponding reference samples (non-irradiated). Clear correlations have been observed between the surface nanostructures and the nucleation field Hc3, which depends on the relative orientation of the magnetic field and the surface patterns developed by the laser irradiation.
KW - Niobium
KW - Surface superconductivity
KW - Laser-induced periodic surface structures (LIPSS)
KW - Nanostructures
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518462
DO - https://doi.org/10.3390/nano10122525
SN - 2079-4991
VL - 10(12)
IS - Special issue "Laser-generated periodic nanostructures"
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-51846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichelt, Manuel
A1 - Cappella, Brunero
T1 - Micro- and nanowear of self-mated steel generated and studied with an AFM at the single asperity level
N2 - We show for the first time tribotests performed with self-mated 100Cr6 steel, taking advantage of an AFM, employed as a tribometer for the tribotests as well as for the inspection of wear of both tribopartners. Emphasis is put on the morphology of the scars, on wear particles, and on wear of the “colloidal” particles glued on the AFM cantilever. Measurements demonstrate the possibility of characterizing single asperity events leading to very small wear. We highlight several phenomena, which are elementary key constituents of tribological processes. Such phenomena, probably occurring also at the macroscale, can be detected, identified, and characterized with high spatial and time resolution only at the nanoscale, thus giving insight into conditions and causes of their emergence.
KW - Nanowear
KW - Atomic force microscope
KW - 100Cr6 (AISI 52100) steel
KW - Wear particles
KW - Single asperity contact
KW - Particle transfer
KW - Zero wear
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531389
DO - https://doi.org/10.3389/fmech.2021.722434
SN - 2297-3079
VL - 7
SP - 1
EP - 16
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-53138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, P.
A1 - Ihlemann, J.
A1 - Bonse, Jörn
T1 - Editorial: Special issue "Laser-generated periodic nanostructures"
N2 - The study of laser-fabricated periodic nanostructures is one of the leading topics of today’s photonics research. Such structures on the surface of metals, semiconductors, dielectrics, or polymers can generate new material properties with special functionalities. Depending on the specific material parameters and the morphology of the structures, new devices such as microlasers, optical nanoswitches, optical storage devices, sensors or antifraud features can be realized. Furthermore, laser-generated surface textures can be used to improve the tribological properties of surfaces in contact and in relative motion—to reduce friction losses or wear, to modify the wettability or the cell and biofilm growth properties of surfaces through bioinspired laser engineering, for emerging medical applications, or as decoration elements for the refinement of precious goods.
This Special Issue “Laser-Generated Periodic Nanostructures” focuses on the latest experimental and theoretical developments and practical applications of laser-generated periodic structures that can be generated in a “self-organized” way (laser-induced periodic surface structures, LIPSS, ripples) or via laser interference-based direct ablation (often referred to as direct laser interference patterning, DLIP). We aimed to attract both academic and industrial researchers in order to collate the current knowledge of nanomaterials and to present new ideas for future applications and new technologies. By 8 August 2021, 22 scientific articles have been published in the Special Issue, see www.mdpi.com/journal/nanomaterials/special_issues/laser-generated_periodic.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Direct laser interference patterning (DLIP)
KW - Surface functionalization
KW - Laser ablation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530980
DO - https://doi.org/10.3390/nano11082054
SN - 2079-4991
VL - 11
IS - 8
SP - 1
EP - 7
PB - MDPI
CY - Basel
AN - OPUS4-53098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martynec, T.
A1 - Karapanagiotis, Christos
A1 - Klapp, S. H. L.
A1 - Kowarik, S.
T1 - Machine learning predictions of surface migration barriers in nucleation and non-equilibrium growth
N2 - Machine learning is playing an increasing role in the discovery of new materials and may also facilitate the search for optimum growth conditions for crystals and thin films. Here, we perform kinetic Monte-Carlo simulations of sub-monolayer growth. We consider a generic homoepitaxial growth scenario that covers a wide range of conditions with different diffusion barriers (0.4–0.55 eV) and lateral binding energies (0.1–0.4 eV). These simulations are used as a training data set for a convolutional neural network that can predict diffusion barriers and binding energies. Specifically, a single Monte-Carlo image of the morphology is sufficient to determine the energy barriers with an accuracy of approximately 10 meV and the neural network is tolerant to images with noise and lower than atomic-scale resolution. We believe this new machine learning method will be useful for fundamental studies of growth kinetics and growth optimization through better knowledge of microscopic parameters.
KW - Machine learning
KW - Surface migration barriers
KW - Material engineering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532523
UR - https://www.nature.com/articles/s43246-021-00188-1
DO - https://doi.org/10.1038/s43246-021-00188-1
SN - 2662-4443
VL - 2
SP - 1
EP - 9
PB - Springer Nature
CY - London
AN - OPUS4-53252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - John, Elisabeth
A1 - Jakob, Cordula
A1 - Pott, Ursula
A1 - Sando, Mona
T1 - Repeatability and reproducibility challenges of isothermal heat flow calorimetry with in situ mixing
N2 - Isothermal heat flow calorimetry evaluates heat development during binder reactions. It distinguishes between in situ calorimetry, where mixing occurs within the device, and ex situ calorimetry, involving externally mixed samples. Despite ex situ calorimetry being a standard method in binder research, in situ calorimetry is underutilized. This paper aims to promote its adoption by summarizing challenges related to repeatability and reproducibility and offering solutions. The initial section addresses repeatability issues caused by preventable errors, providing a structured guide for experimental design. It was found that water leakage had minimal impact, and sample size is crucial for data robustness. The second section examines operational challenges, revealing that frictional heating, affecting recorded heat, can be minimized with an optimized mixing protocol. The final part highlights that significant errors in measured data stem from signal delay and heat loss, offering methods to correct these issues for improved reproducibility in in situ calorimetric experiments.
KW - In situ calorimetry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628431
DO - https://doi.org/10.1016/j.cemconres.2025.107872
SN - 1873-3948
VL - 194
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-62843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Eine Sammlung durch Maschinelles Lernen unterstützter Verteilter Faseroptischer Sensoren für Infrastrukturmonitoring
T1 - A collection of machine learning assisted distributed fiber optic sensors for infrastructure monitoring
N2 - In this paper, we present a collection of machine learning assisted distributed fiber optic sensors (DFOS) for applications in the field of infrastructure monitoring. We employ advanced signal processing based on artificial neural networks (ANNs) to enhance the performance of the dynamic DFOS for strain and vibration sensing. Specifically, ANNs in comparison to conventional and computationally expensive correlation and linearization algorithms, deliver lower strain errors and speed up the signal processing allowing real time strain monitoring. Furthermore, convolutional neural networks (CNNs) are used to denoise the dynamic DFOS signal and enable useable sensing lengths of up to 100 km. Applications of the machine learning assisted dynamic DFOS in road traffic and railway infrastructure monitoring are demonstrated. In the field of static DFOS, machine learning is applied to the well-known Brillouin optical frequency domain analysis (BOFDA) system. Specifically, CNN are shown to be very tolerant against noisy spectra and contribute towards significantly shorter measurement times. Furthermore, different machine learning algorithms (linear and polynomial regression, decision trees, ANNs) are applied to solve the well-known problem of cross-sensitivity in cases when temperature and humidity are measured simultaneously. The presented machine learning assisted DFOS can potentially contribute towards enhanced, cost effective and reliable monitoring of infrastructures.
N2 - In diesem Beitrag stellen wir eine Sammlung von verteilten faseroptischen Sensoren (DFOS) vor, die mit Hilfe von Maschinellem Lernen arbeiten und für Anwendungen im Bereich der Infrastrukturüberwachung geeignet sind. Wir setzen hierbei fortschrittliche Signalverarbeitung auf der Grundlage Künstlicher Neuronaler Netze ein, um die Leistungsfähigkeit dynamischer DFOS für die Messung von Dehnungen und Vibrationen zu verbessern. Insbesondere Künstliche Neuronale Netze (ANNs) liefern im Vergleich zu konventionellen und rechenintensiven Korrelations- und Linearisierungsalgorithmen geringere Dehnungsfehler und beschleunigen die Signalverarbeitung, so dass eine Dehnungsüberwachung in Echtzeit möglich ist. Darüber hinaus wenden wir Convolutional Neural Networks (CNNs) an, um dynamische DFOS-Signale zu entrauschen und damit nutzbare Messlängen von bis zu 100 km zu ermöglichen. Es werden Anwendungsbeispiele dieser durch Maschinelles Lernen unterstützten dynamischen DFOS in den Bereichen des Straßenverkehrsmonitorings und der Zug- und Gleisüberwachung aufgezeigt. Im Bereich der statischen DFOS wird Maschinelles Lernen auf das Verfahren der Optischen Brillouin-Frequenzbereichsanalyse (BOFDA) angewendet. Insbesondere CNN erweisen sich hier als sehr robust gegenüber verrauschten Spektren und tragen zu deutlich kürzeren Messzeiten bei. Darüber hinaus werden verschiedene Algorithmen des maschinellen Lernens (lineare und polynome Regression, Entscheidungsbäume, ANNs) angewandt, um das bekannte Problem der Querempfindlichkeit bei DFOS in den Fällen zu lösen, in denen Temperatur und Feuchtigkeit gleichzeitig gemessen werden sollen. Die hier vorgestellten, durch Maschinelles Lernen unterstützten, DFOS können zu einer verbesserten, kostengünstigen und zuverlässigen Überwachung von Infrastrukturen beitragen.
KW - Artificial neural networks
KW - Brillouin sensing
KW - Distributed acoustic sensing
KW - Fibre optic sensors
KW - Infrastructure monitoring
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569044
DO - https://doi.org/10.1515/teme-2022-0098
SN - 0171-8096
SP - 1
EP - 19
PB - De Gruyter
AN - OPUS4-56904
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Patrick
A1 - Schneider, Ronald
A1 - Baeßler, Matthias
A1 - Morgenthal, Guido
ED - Cha, Young-Jin
T1 - A Bayesian Probabilistic Framework for Building Models for Structural Health Monitoring of Structures Subject to Environmental Variability
N2 - Managing aging engineering structures requires damage identification, capacity reassessment, and prediction of remaining service life. Data from structural health monitoring (SHM) systems can be utilized to detect and characterize potential damage. However, environmental and operational variations impair the identification of damages from SHM data. Motivated by this, we introduce a Bayesian probabilistic framework for building models and identifying damage in monitored structures subject to environmental variability. The novelty of our work lies (a) in explicitly considering the effect of environmental influences and potential structural damages in the modeling to enable more accurate damage identification and (b) in proposing a methodological workflow for model‐based structural health monitoring that leverages model class selection for model building and damage identification. The framework is applied to a progressively damaged reinforced concrete beam subject to temperature variations in a climate chamber. Based on deflections and inclinations measured during diagnostic load tests of the undamaged structure, the most appropriate modeling approach for describing the temperature‐dependent behavior of the undamaged beam is identified. In the damaged state, damage is characterized based on the identified model parameters. The location and extent of the identified damage are consistent with the cracks observed in the laboratory. A numerical study with synthetic data is used to validate the parameter identification. The known true parameters lie within the 90% highest density intervals of the posterior distributions of the model parameters, suggesting that this approach is reliable for parameter identification. Our results indicate that the proposed framework can answer the question of damage identification under environmental variations. These findings show a way forward in integrating SHM data into the management of infrastructures.
KW - Verkehrsinfrastukturen
KW - SHM
KW - Model Updating
KW - Environmental and Operational Variability
KW - Damage Identification
KW - Model Building
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605027
DO - https://doi.org/10.1155/2024/4204316
SN - 1545-2255
VL - 2024
IS - 1
SP - 1
EP - 23
PB - Wiley
AN - OPUS4-60502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baeßler, Matthias
A1 - Simon, Patrick
T1 - Ballasted track on vibrating bridge decks: physical mechanisms, empirical findings, and a proposal for assessment
N2 - This paper summarizes the key findings and physical mechanisms and provides information on open questions and the assessment of railway bridge superstructure vibrations. Bridges are classic disruption points on a railway track. If bridge superstructures are dynamically excited by train traffic, the vertical accelerations of the track must be considered. For a ballasted track, this can lead to the destabilization of the ballast track, as the bridge superstructure acts like a vibrating table. In this respect, the paper explains in more detail what is meant by destabilization, when this destabilization occurs and how various influencing parameters such as acceleration amplitude, the vibration sequence and frequency affect its occurrence. In the InBridge4EU project, gaps in knowledge such as the effect of single impulse loads are being investigated experimentally. A new test facility has been set up for this purpose, the initial results of which are presented here. An essential element in the assessment of this scenario is the stability of the track under high compression forces with simultaneous dynamic excitation of the superstructure. A new approach for the assessment of bridge vibrations with respect to lateral stability is presented.
KW - Railway bridge dynamics
KW - Bridge deck acceleration
KW - Ballast destabilization
KW - Lateral track stability
KW - Track buckling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630972
DO - https://doi.org/10.1142/S0219455425400243
SN - 0219-4554
SN - 1793-6764
IS - 2540024
SP - 1
EP - 27
PB - World Scientific
CY - Singapore
AN - OPUS4-63097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herrmann, Ralf
A1 - Ramasetti, Eshwar Kumar
A1 - Degener, Sebastian
A1 - Hille, Falk
A1 - Baeßler, Matthias
T1 - A living lab for Structural Health Monitoring at the Nibelungen Bridge Worms for Transfer Learning of Structural Dynamics
N2 - The Nibelungen Bridge in Worms, Germany has been selected as a national demonstration structure for advanced non-destructive testing (NDT) and structural health monitoring concepts to extend the lifetime of civil structures and to optimize O&M actions. Parts of the research that involves this bridge as a demonstrator belong to the focus area program SPP100+. In this program, the bridges SHM System has been extended and combined with an additional setup of vibration sensors. The used digital smart sensor with pre-processing functions, the arrangement of the sensors at the structure and additional edge computing capability allows the investigation of transfer learning and other methods directly into the real structure. The living lab with seven triaxial accelerometers can be reconfigured in real-time and adjusted to the needs of AI models for classification. The comparison with the existing conventional SHM sensors has been made possible by hardware synchronization to the existing SHM System and collocating sensors at similar positions, so that a hardware exchange can be an investigated use-case for the transfer learning. During idle times, the system collects vibration data like a conventional SHM system.
T2 - 10th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam
DA - 10.06.2024
KW - Nibelungen Bridge
KW - Living Lab
KW - Transfer Learning
KW - Transfer Structures
KW - Modal Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612810
UR - https://www.ndt.net/search/docs.php3?id=29853
DO - https://doi.org/10.58286/29853
SN - 1435-4934
VL - 29
IS - 7
SP - 1
EP - 8
PB - NDT.net GmbH & Co. KG
CY - Mayen
AN - OPUS4-61281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Simon, Patrick
A1 - Baeßler, Matthias
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Temperatureinfluss auf Strukturmonitoring – Aktuelle Versuche
N2 - Strukturmonitoring kann wertvolle Daten für die Zustandsbewertung und Schadensdetektion von Infrastrukturbauwerken liefern. Umgebungsbedingungen wie die Temperatur beeinflussen die Bauwerke und somit die Messdaten jedoch erheblich. Um Methoden für den Umgang mit Temperatureinflüssen zu entwickeln, wurden an der BAM Versuche an Stahlbeton- und Asphaltbalken unter kontrollierten Temperaturen von -40 °C bis 60 °C und definierten Schädigungen durchgeführt. Die Daten ermöglichen die Erforschung und Validierung neuer, auch unter Temperatureinfluss zuverlässiger Methoden des Strukturmonitorings.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Strukturmonitoring
KW - Temperatureinfluss
KW - Infrastrukturbauwerke
KW - Stahlbeton- und Asphaltbalken
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613289
SN - 978-3-9818564-7-7
SP - 294
EP - 302
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61328
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ramasetti, Eshwar Kumar
A1 - Herrmann, Ralf
A1 - Degener, Sebastian
A1 - Baeßler, Matthias
T1 - Development of generic AI models to predict the movement of vehicles on bridges
N2 - For civil, mechanical, and aerospace structures to extend operation times and to remain in service, structural health monitoring (SHM) is vital. SHM is a method to examining and monitoring the dynamic behavior of essential constructions. Because of its versatility in detecting unfavorable structural changes and enhancing structural dependability and life cycle management, it has been extensively used in many engineering domains, especially in civil bridges. Due to the recent technical developments in sensors, high-speed internet, and cloud computing, data-driven approaches to structural health monitoring are gaining appeal. Since artificial intelligence (AI), especially in SHM, was introduced into civil engineering, these modern and promising methods have attracted significant research attention. In this work, a large dataset of acceleration time series using digital sensors was collected by installing a structural health monitoring (SHM) system on Nibelungen Bridge located in Worms, Germany. In this paper, a deep learning model is developed for accurate classification of different types of vehicle movement on the bridge from the data obtained from accelerometers. The neural network is trained with key features extracted from the acceleration dataset and classification accuracy of 98 % was achieved.
KW - Structural Health Monitoring
KW - Artifical Intelligence
KW - Machine Learning
KW - Nibelungen Bridge
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620289
DO - https://doi.org/10.1016/j.prostr.2024.09.307
VL - 64
SP - 557
EP - 564
PB - Elsevier B.V.
AN - OPUS4-62028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thiele, Marc
A1 - Pirskawetz, Stephan
A1 - Baeßler, Matthias
A1 - Rogge, Andreas
T1 - Untersuchung der Schädigungsevolution in Beton unter Ermüdungsbeanspruchung mit Hilfe der Schallemissionsanalyse
N2 - Unter zyklischen Belastungen findet im Beton, wie bei anderen Materialien auch, ein Ermüdungsprozess statt, der letztlich im Versagen des Materials enden kann. Im derzeitigen Erkenntnisstand zum Materialverhalten des Betons gibt es gerade bei dessen Ermüdungsverhalten noch viele nicht oder nicht ausreichend geklärte Fragestellungen. Deshalb wurde in Laborversuchen das Ermüdungsverhalten von Beton unter Druckschwellbeanspruchungen untersucht. Im Fokus dieser Untersuchungen standen dabei die während der Lebensdauer im Materialgefüge ablaufenden Prozesse, die zur Schädigung des Gefüges und schließlich auch zum Ermüdungsversagen führen können.
In den Ermüdungsversuchen wurden versuchsbegleitend Dehnungsmessungen, Ultraschall-Laufzeitmessungen und Schallemissionsmessungen an den Proben zur Erfassung der Schädigungsevolution eingesetzt. Die Schallemissionsmessung ist dabei ein wichtiges Instrument, da sie die Rissentwicklungsprozesse detektiert, die die Ursache für die Materialschädigung sind. Mit ihr konnten die unterschiedlichen Phasen der Rissentwicklungen über die gesamte Lebensdauer der Betonproben festgestellt werden. Diese Phasen sind gekennzeichnet durch sich stabilisierende, stabile und instabile Rissprozesse, die entsprechende Auswirkungen auf das Materialverhalten haben. Ein Vergleich mit den Ergebnissen der anderen Messtechniken zeigt den entsprechenden Einfluss der Rissentwicklungen auf die Materialeigenschaften des Betons.
T2 - 18. Kolloquium Schallemission
CY - Wetzlar, Deutschland
DA - 27.10.2011
KW - Beton
KW - Ermüdung
KW - Schallemission
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-247223
SN - 978-3-940283-37-5
IS - DGZfP-BB 131 (Vortrag 02)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24722
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorzi, G.
A1 - Baeßler, Matthias
A1 - Gabrieli, Fabio
T1 - Influence of structural stiffness on ratcheting convection cells of granular soil under cyclic lateral loading
N2 - In granular soils, long-term cyclically loaded structures can lead to an accumulation of irreversible strain by forming closed convective cells in the upper layer of the bedding. The size of the convective cell, its formation and grain migration inside this closed volume have been studied with reference to different stiffness of the embedded structure and different maximum force amplitudes applied at the head of the structure.
This relation was experimentally investigated by applying a cyclic lateral force to a scaled flexible vertical element embedded in a dry granular soil. The model was monitored with a camera in order to derive the displacement field by means of the PIV technique. Furthermore, the ratcheting convective cell was also simulated with DEM with the aim of extracting some micromechanical information. The main results regarded the different development, shape and size of the convection cell and the surface settlements.
T2 - 1st International Conference on the Material Point Method, MPM 2017
CY - Deltares, Delft, The Netherlands
DA - 10.01.2017
KW - Particle image velocimetry
KW - Cyclic loading
KW - Discrete element method
KW - Ratcheting convective cell
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395711
DO - https://doi.org/10.1016/j.proeng.2017.01.046
SN - 1877-7058
IS - 175
SP - 148
EP - 156
PB - Elsevier
AN - OPUS4-39571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asna Ashari, Parsa
A1 - Oh, Hyochan
A1 - Koch, Claudia
T1 - Pathways to the hydrogen economy: A multidimensional analysis of the technological innovation systems of Germany and South Korea
N2 - The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry, politics, and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition, this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologies in Germany and South Korea, both recognized as global frontrunners in advancing and implementing hydrogen-based solutions. By providing a multidimensional assessment of pathways to the hydrogen economy, our analysis introduces two novel and crucial elements to the TIS analysis: (i) We integrate the concept of ‘quality infrastructure’ given the relevance of safety and quality assurance for technology adoption and social acceptance, and (ii) we emphasize the social perspective within the hydrogen TIS. To this end, we conducted 24 semi-structured expert interviews, applying qualitative open coding to analyze the data. Our results indicate that the hydrogen TISs in both countries have undergone significant developments across various dimensions. However, several barriers still hinder the further realization of a hydrogen economy. Based on our findings, we propose policy implications that can facilitate informed policy decisions for a successful hydrogen transition.
KW - Hydrogen economy
KW - Technological innovation system
KW - Quality infrastructure
KW - Multidimensional technology adoption
KW - Social acceptance
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593312
DO - https://doi.org/10.1016/j.ijhydene.2023.08.286
IS - Volume 49, Part D
SP - 405
EP - 421
PB - Elsevier
AN - OPUS4-59331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Sebastian
A1 - Cappella, Brunero
T1 - Friction and mechanical properties of AFM-scan-induced ripples in polymer films
N2 - In the present paper, friction and mechanical properties of AFM-Scan-Induced ripple structures on films of polystyrene and poly-n-(butyl methacrylate) are investigated. Force volume measurements allow a quantitative analysis of the elastic moduli with nanometer resolution, showing a contrast in mechanical response between bundles and troughs. Additionally, analysis of the lateral cantilever deflection shows a clear correlation between friction and the sample topography. Those results support the theory of crack propagation and the formation of voids as a mechanism responsible for the formation of ripples. This paper also shows the limits of the presented measuring methods for soft, compliant, and small structures.
KW - AFM
KW - Polymer
KW - Ripples
KW - Mechanical properties
KW - Friction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532772
DO - https://doi.org/10.3389/fmech.2021.672898
SN - 2297-3079
VL - 7
SP - 1
EP - 8
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-53277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Gräf, S.
T1 - Ten Open Questions about Laser-Induced Periodic Surface Structures
N2 - Laser-induced periodic surface structures (LIPSS) are a simple and robust route for the nanostructuring of solids that can create various surface functionalities featuring applications in optics, medicine, tribology, energy technologies, etc. While the current laser technologies already allow surface processing rates at the level of m2/min, industrial applications of LIPSS are sometimes hampered by the complex interplay between the nanoscale surface topography and the specific surface chemistry, as well as by limitations in controlling the processing of LIPSS and in the long-term stability of the created surface functions. This Perspective article aims to identify some open questions about LIPSS, discusses the pending technological limitations, and sketches the current state of theoretical modelling. Hereby, we intend to stimulate further research and developments in the field of LIPSS for overcoming these limitations and for supporting the transfer of the LIPSS technology into industry.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Industrial application
KW - Functional properties
KW - Surface functionalization
KW - Modelling
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539503
DO - https://doi.org/10.3390/nano11123326
SN - 2079-4991
VL - 11
IS - 12
SP - 1
EP - 21
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-53950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiele, Marc
A1 - Pirskawetz, Stephan
T1 - Analysis of damage evolution in concrete under fatigue loading by acoustic emission and ultrasonic testing
N2 - The fatigue process of concrete under compressive cyclic loading is still not completely explored. The corresponding damage processes within the material structure are especially not entirely investigated. The application of acoustic measurement methods enables a better insight into the processes of the fatigue in concrete. Normal strength concrete was investigated under compressive cyclic loading with regard to the fatigue process by using acoustic methods in combination with other nondestructive measurement methods. Acoustic emission and ultrasonic signal measurements were applied together with measurements of strains, elastic modulus, and static strength. It was possible to determine the anisotropic character of the fatigue damage caused by uniaxial loading based on the ultrasonic measurements. Furthermore, it was observed that the fatigue damage seems to consist not exclusively of load parallel oriented crack structures. Rather, crack structures perpendicular to the load as well as local compacting are likely components of the fatigue damage. Additionally, the ultrasonic velocity appears to be a good indicator for fatigue damage beside the elastic modulus. It can be concluded that acoustic methods allow an observation of the fatigue process in concrete and a better understanding, especially in combination with further measurement methods.
KW - Concrete
KW - Fatigue
KW - Damage evolution
KW - Ultrasonic testing
KW - Acoustic emission
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541891
DO - https://doi.org/10.3390/ma15010341
SN - 1996-1944
VL - 15
IS - 1
SP - 341
EP - 355
PB - MDPI
CY - Basel
AN - OPUS4-54189
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Porta-Velilla, L.
A1 - Turan, N.
A1 - Cubero, Á.
A1 - Shao, W.
A1 - Li, H.
A1 - de la Fuente, G.F.
A1 - Martínez, E.
A1 - Larrea, Á.
A1 - Castro, M.
A1 - Koralay, H.
A1 - Çavdar, Ş.
A1 - Bonse, Jörn
A1 - Angurel, L.A.
T1 - Highly Regular Hexagonally-Arranged Nanostructures on Ni-W Alloy Tapes upon Irradiation with Ultrashort UV Laser Pulses
N2 - Nickel tungsten alloy tapes (Ni—5 at% W, 10 mm wide, 80 µm thick, biaxially textured) used in second-generation high temperature superconductor (2G-HTS) technology were laser-processed in air with ultraviolet ps-laser pulses (355 nm wavelength, 300 ps pulse duration, 250–800 kHz pulse repetition frequency). By employing optimized surface scan-processing strategies, various laser-generated periodic surface structures were generated on the tapes. Particularly, distinct surface microstructures and nanostructures were formed. These included sub-wavelength-sized highly-regular hexagonally-arranged nano-protrusions, wavelength-sized line-grating-like laser-induced periodic surface structures (LIPSS, ripples), and larger irregular pyramidal microstructures. The induced surface morphology was characterized in depth by electron-based techniques, including scanning electron microscopy (SEM), electron back scatter diffraction (EBSD), cross-sectional transmission electron microscopy (STEM/TEM) and energy dispersive X-ray spectrometry (EDS). The in-depth EBSD crystallographic analyses indicated a significant impact of the material initial grain orientation on the type of surface nanostructure and microstructure formed upon laser irradiation. Special emphasis was laid on high-resolution material analysis of the hexagonally-arranged nano-protrusions. Their formation mechanism is discussed on the basis of the interplay between electromagnetic scattering effects followed by hydrodynamic matter re-organization after the laser exposure. The temperature stability of the hexagonally-arranged nano-protrusion was explored in post-irradiation thermal annealing experiments, in order to qualify their suitability in 2G-HTS fabrication technology with initial steps deposition temperatures in the range of 773–873 K.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser processing
KW - Hexagonally-arranged nano-protrusions
KW - Second-generation high temperature superconductor technology
KW - Electron microscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552551
DO - https://doi.org/10.3390/nano12142380
SN - 2079-4991
VL - 12
IS - 14
SP - 1
EP - 23
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qiao, Linan
A1 - Nagelschmidt, Sven
A1 - Herbrich, Uwe
A1 - Keller, Christian
T1 - Introduction of a Power Law Time-Temperature Equivalent Formulation for the Description of Thermorheologically Simple and Complex Behavior
N2 - Abstract: In this work, a conceptual framework is suggested for analyzing thermorheologically simple and complex behavior by using just one approach. Therefore, the linear relation between master time and real time which is required in terms of the time-temperature superposition principle was enhanced to a nonlinear equivalent relation. Furthermore, we evaluate whether there is any relation among well-known existing time-temperature equivalent formulations which makes it possible to generalize different existing formulations. For this purpose, as an example, the power law formulation was used for the definition of the master time. The method introduced here also contributes a further framework for a unification of established time-temperature equivalent formulations, for example the time-temperature superposition principle and time-temperature parameter models. Results show, with additional normalization conditions, most of the developed time-temperature parameter models can be treated as special cases of the new formulation. In the aspect of the arrow of time, the new defined master time is a bended arrow of time, which can help to understand the corresponding physical meaning of the suggested method.
KW - bended arrow of time
KW - time-temperature superposition principle
KW - time-temperature equivalent formulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543800
DO - https://doi.org/10.3390/ma15030726
VL - 15
IS - 3
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-54380
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Grabowski, Sven
A1 - Sahrhage, H.
A1 - Lampke, T.
T1 - Electrochemical corrosion investigations on binary and ternary zinc alloy coatings using gel electrolytes
N2 - Novel agar-based test electrolytes are used to perform electrochemical corrosion investigations on ZnFe and ZnNi binary as well as ZnFeMo ternary zinc coatings. The objectives of the electrochemical investigations include the characterization of the corrosion behavior, the description of the protective effect of the coatings as well as the investigation of the layer formation and degradation under artificial aging. ZnFe and ZnFeMo coatings are applied with varying iron content as well as an additional passivation layer, respectively, to study the effect on corrosion resistance. The results show that the protective effect of the coatings is not negatively influenced by different iron contents or the addition of molybdenum. Additional passivation of the ZnFe-containing coatings by means of a passivating agent leads to a significant improvement in the protective effect. Artificial aging leads to slight degradation of the additional passivation layer whereas coatings without post-treatment enhance their protective effect by the formation of corrosion product layers.
KW - Binary zinc alloys
KW - Ternary zinc alloys
KW - Corrosion testing
KW - Gel electrolytes
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543013
DO - https://doi.org/10.1002/adem.202101336
SN - 1438-1656
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weise, Frank
A1 - von Werder, Julia
A1 - Manninger, Tanja
A1 - Maier, Bärbel
A1 - Fladt, Matthias
A1 - Simon, Sebastian
A1 - Gardei, Andre
A1 - Höhnel, Desirée
A1 - Pirskawetz, Stephan
A1 - Meng, Birgit
T1 - A multiscale and multimethod approach to assess and mitigate concrete damage due to alkali-silica reaction
N2 - Alkali-silica reaction (ASR) is a chemical reaction within concrete which can lead over time to cracking and spalling. Due to the complexity of the problem, it still causes damage to concrete constructions worldwide.
The publication aims to illustrate the interdisciplinary research of the German Federal Institute for Materials Research and Testing (BAM) within the last 20 years, considering all aspects of ASR topics from the macro to the micro level. First, methods for characterization and assessment of ASR risks and reaction products used at BAM are explained and classified in the international context. Subsequently the added value of the research approach by combining different, preferably nondestructive, methods across all scales is explained using specific examples from a variety of research projects. Aspects covered range from the development of new test-setups to assess aggregate reactivity, to analysis of microstructure and reaction products using microscopical, spectroscopical and X-ray methods, to the development of a testing methodology for existing concrete pavements including in-depth analysis of the visual damage indicator and the de-icing salt input using innovative testing techniques. Finally, research regarding a novel avoidance strategy that makes use of internal hydrophobization of the concrete mix is presented.
KW - Mitigation strategies
KW - Concrete
KW - Damage analysis
KW - Alkali silica reaction
KW - Road pavement
KW - Accelerated testing
KW - Non-destructive testing
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:101:1-2022052515100075090235
DO - https://doi.org/10.1002/adem.202101346
SN - 1527-2648
VL - 24
IS - 6
SP - 1
EP - 36
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lüdicke, M. G.
A1 - Hildebrandt, Jana
A1 - Schindler, C.
A1 - Sperling, R. A.
A1 - Maskos, M.
T1 - Automated QuantumDots Purification via Solid Phase Extraction
N2 - The separation of colloidal nanocrystals from their original synthesis medium is an essential process step towards their application, however, the costs on a preparative scale are still a constraint. A new combination of approaches for the purification of hydrophobic Quantum Dots is presented, resulting in an efficient scalable process in regard to time and solvent consumption, using common laboratory equipment and low-cost materials. The procedure is based on a combination of solvent-induced adhesion and solid phase extraction. The platform allows the transition from manual handling towards automation, yielding an overall purification performance similar to one conventional batch precipitation/centrifugation step, which was investigated by thermogravimetry and gas chromatography. The distinct miscibility gaps between surfactants used as nanoparticle capping agents, original and extraction medium are clarified by their phase diagrams, which confirmed the outcome of the flow chemistry process. Furthermore, the solubility behavior of the Quantum Dots is put into context with the Hansen solubility parameters framework to reasonably decide upon appropriate solvent types.
KW - Quantum Dots
KW - Purification
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559590
DO - https://doi.org/10.3390/nano12121983
SN - 2079-4991
VL - 12
IS - 12
PB - MDPI
CY - Basel
AN - OPUS4-55959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lifka, S.
A1 - Harsányi, K.
A1 - Baumgartner, E.
A1 - Pichler, L.
A1 - Baiko, D.
A1 - Wasmuth, Karsten
A1 - Heitz, J.
A1 - Meyer, M.
A1 - Joel, A.-C.
A1 - Bonse, Jörn
A1 - Baumgartner, W.
ED - Mail, M.
T1 - Laser-processed antiadhesive bionic combs for handling nanofibers inspired by nanostructures on the legs of cribellate spiders
N2 - Nanofibers are drawing the attention of engineers and scientists because their large surface-to-volume ratio is favorable for applications in medicine, filter technology, textile industry, lithium-air batteries, and optical sensors. However, when transferring nanofibers to a technical product in the form of a random network of fibers, referred to as nonwoven fabric, the stickiness of the freshly produced and thus fragile nanofiber nonwoven remains a problem. This is mainly because nanofibers strongly adhere to any surface because of van der Waals forces. In nature, there are animals that are actually able to efficiently produce, process, and handle nanofibers, namely cribellate spiders. For that, the spiders use the calamistrum, a comb-like structure of modified setae on the metatarsus of the hindmost (fourth) legs, to which the 10–30 nm thick silk nanofibers do not stick due to a special fingerprint-like surface nanostructure. In this work, we present a theoretical model of the interaction of linear nanofibers with a sinusoidally corrugated surface. This model allows for a prediction of the adhesive interaction and, thus, the design of a suitable surface structure to prevent sticking of an artificially nonwoven of nanofibers. According to the theoretical prediction, a technical analogon of the nanoripples was produced by ultrashort pulse laser processing on different technically relevant metal surfaces in the form of so-called laser-induced periodic surface structures (LIPSS). Subsequently, by means of a newly established peel-off test, the adhesion of an electrospun polyamide fiber-based nonwoven was quantified on such LIPSS-covered aluminium alloy, steel, and titanium alloy samples, as well as on polished (flat) control samples as reference and, additionally, on samples with randomly rough surfaces. The latter revealed that the adhesion of electrospun nanofiber nonwoven is significantly lowered on the nanostructured surfaces compared with the polished surfaces.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Cribellate spiders
KW - Calamistrum
KW - Electrospinning
KW - Nanofibers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561799
DO - https://doi.org/10.3762/bjnano.13.105
SN - 2190-4286
VL - 13
SP - 1268
EP - 1283
PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften
CY - Frankfurt, M.
AN - OPUS4-56179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, Sven
A1 - Jaenisch, Gerd-Rüdiger
A1 - Pavasaryte, Lina
A1 - Funk, Alexander
T1 - XCT and DLW: Synergies of Two Techniques at Sub-Micrometer Resolution
N2 - Direct Laser Writing (DLW) and X-ray computed tomography (XCT) both offer unique possibilities in their respective fields. DLW produces full three-dimensional (3D) polymer structures on the microscale with resolutions below 100 nm. The fabricated structures can be analysed by XCT or X-ray microscopy (XRM), which incorporates additional X-ray lenses, in three dimensions down to a minimal basic spatial resolution of about 500 nm or 50 nm, respectively. In this work, two different DLW structures are analysed via XCT. Internal defects are detected and analysed for the purpose of quality control. Defects and structures with sizes down to 1.5 µm are successfully analysed. A 3D reconstruction and internal, hidden features of the fabricated structures are shown and discussed. In a first-of-its-kind study, we demonstrate the detectability of a single-voxel line inside a fabricated structure that would not be detectable with SEM or light microscopy. Furthermore, the direct fabrication on a PET substrate is shown to overcome the high X-ray absorbance of commonly used glass substrates. Attenuation spectra of SZ2080 and glass substrates are compared to a fabrication route direct on a 170 µm PET foil. The practical aspects of XCT measurements for DLW structures on different substrates will be discussed.
KW - Non-destructive testing
KW - Two-photon polymerization
KW - X-ray microscopy
KW - XCT
KW - 2PP
KW - Direct laser writing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560525
DO - https://doi.org/10.3390/app122010488
VL - 12
IS - 20
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-56052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Lehmann, Jens
A1 - Burkert, Andreas
T1 - Field exposure study under sheltered and open exposure conditions at different test sites in Germany: First‐year corrosion rate and atmospheric corrosivity
N2 - The corrosivity of atmospheres in Europe has changed significantly in recent decades. For the Federal Republic of Germany, no current values for the corrosion rate based on 1‐year atmospheric exposure of standard specimens can be found in the scientific literature after 2000. This paper presents results from a field exposure study in the Berlin metropolitan area and Helgoland in 2016. Based on standard specimens, values for the corrosion rate and the corresponding atmospheric corrosivity category are determined for open exposure and indirect weathering in a ventilated enclosure as sheltering after 1 year of exposure. The results prove that determined corrosivity categories are material‐specific. Sheltered exposure is a typical atmospheric situation for many building components. It allows statements on the effect of the concentration of airborne substances on the corrosivity beyond the normative requirements.
KW - Atmospheric corrosion
KW - Corrosivity category
KW - ISO 9223
KW - Mass loss
KW - Atmosphärische Korrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565099
DO - https://doi.org/10.1002/maco.202213582
SN - 0947-5117 (print)
SN - 1521-4176 (online)
SP - 1
EP - 15
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-56509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - Structuring of thin films by ultrashort laser pulses
N2 - Modern life and global communication would not be possible without technologically tailored thin films; they are omnipresent in daily life applications. In most cases, the films are deposited entirely at the carrying substrates in a specific processing step of the device or sample. In some cases, however, removal or modification must be performed locally, i.e., site-controlled and material selective through an additional laser processing step. For that ultrashort laser pulses with durations in the femtosecond and picosecond range can provide unique advantages and capabilities in industrially scalable schemes. This article reviews the current state of the research and corresponding industrial transfer related to the structuring of thin films by ultrashort pulsed lasers. It focuses on the pertinent historic developments, reveals the relevant physical and chemical effects, explores the ultimate limits, and discusses selected industrial and scientific applications.
KW - Thin films
KW - Laser processing
KW - Ultrashort lasers
KW - Laser damage
KW - Femtosecond laser ablation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565732
DO - https://doi.org/10.1007/s00339-022-06229-x
SN - 0947-8396
SN - 1432-0630
VL - 129
IS - 1
SP - 1
EP - 38
PB - Springer
CY - Berlin
AN - OPUS4-56573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costache, F.
A1 - Valette, S.
A1 - Bonse, Jörn
T1 - Editorial: Special Issue “Dynamics and Processes at Laser-Irradiated Surfaces—A Themed Issue in Honor of the 70th Birthday of Professor Jürgen Reif”
N2 - The Special Issue “Dynamics and Processes at Laser-irradiated Surfaces” is dedicated to the 70th birthday of Jürgen Reif, retired full professor, former Chair of Experimental Physics II of the Faculty of Physics of the Brandenburg University of Technology Cottbus—Senftenberg in Germany.
KW - Laser ablation
KW - Laser-induced periodic surface structures (LIPSS)
KW - Surface functionalization
KW - Femtosecond laser
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569482
DO - https://doi.org/10.3390/nano13030611
SN - 2079-4991
VL - 13
IS - 3
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-56948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cappella, Brunero
A1 - Spaltmann, Dirk
A1 - Gee, M.
T1 - Editorial: Tribology and Atomic Force Microscopy - Towards Single Asperity Contact
N2 - The concept behind this Research Topic (RT) was to collect works, in which Atomic Force Microscopy (AFM) techniques are employed to study tribological phenomena and to push the resolution of measurements towards single asperity contact. Thanks to the direct determination of sample height with sub-nanometer resolution and the possibility of measuring local friction, AFM can be employed after a tribotest to detect topography and friction changes at the nanometer scale. Recently, efforts are being expended to use AFM cantilevers as tribometers, i.e., as probes altering the volume of suitable samples, thereby measuring tip and/or sample wear and friction at the nano/microscale. Thus, single asperity contact, friction, and wear can be investigated. Since friction and wear at the macroscale are the result of asperities interactions, such experiments are of great importance for better understanding of tribological processes.
KW - Nanotribology
KW - Friction
KW - Wear
KW - Single asperity
KW - AFM
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571037
DO - https://doi.org/10.3389/fmech.2022.853934
SN - 2297-3079
VL - 8
SP - 1
EP - 2
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-57103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Swaminathan, Srinivasan
A1 - Kumar, S.
A1 - Kranzmann, Axel
A1 - Hesse, Rene
A1 - Goldbeck, Hennig
A1 - Fantin, Andrea
T1 - Corrosion characteristics of 316L stainless steel in oxide-rich molten solar salt at 600◦C
N2 - An attempt has been made in this work, to observe the influence on alloy aging by the sodium oxide (Na2O) in solar salt (60 wt% NaNO3 + 40 wt% KNO3). The accelerated aging was established by adding Na2O (0.005, 0.07, 0.135 and 0.2 wt%) to the solar salt and their effect on corrosion of 316L stainless steel (SS) at 600 ◦C in that oxide-rich solar salts for 168 h in synthetic air was investigated. Corrosion is significantly more in oxide-rich solar salt compared to pure solar salt. Strikingly, the oxide scale-base metal interface is wavy in solar salt containing 0.005 % Na2O clearly shows the oxide addition to salt melt influences Cr-rich inner oxide layer formation and its selective dissolution at early stage that leads to non-uniform corrosion. Interestingly, with increase of Na2O to 0.07 %, steel corrosion proceeded uniformly by accelerated disintegration of Cr-rich inner layer and subsequent dissolution. Severe scale spallation and weight loss in nitrate melt containing 0.2 % Na2O fostering more rapid corrosion, alarming that substantial tolerance of oxide content in solar salt is ≥ 0.135 % for an acceptable corrosion of 316L SS. Despite preferential dissolution of Cr and scale degradation/spallation with increased oxide content in solar salt, the corrosion layer in all cases comprised of sodium ferrite, and Cr-rich Cr-Fe mixed oxides with the Ni enrichment at the scale-metal interface. Competing processes between oxide scale growth, degradation and dissolution or even spallation has been discussed with an emphasis of Na2O addition to solar salt.
KW - Molten salt corrosion
KW - Solar salt
KW - Thermal energy storage
KW - Stainless steel
KW - Concentrating solar power
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610819
DO - https://doi.org/10.1016/j.solmat.2024.113176
VL - 278
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-61081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lauhoff, Christian
A1 - Degener, Sebastian
A1 - Bolender, Artjom
A1 - Liehr, Alexander
A1 - Hübner, Leoni
A1 - Frenck, Johanna-Maria
A1 - Molotnikov, Andrey
A1 - Niendorf, Thomas
T1 - In Situ Synchrotron Diffraction Assessment of Reversibility of the Martensitic Transformation in Single-Crystalline Co–Ni–Ga Shape Memory Alloy Under Torsion
N2 - AbstractHeusler-type Co–Ni–Ga shape memory alloys attracted significant attention due to their excellent functional properties in single-crystalline state under both compressive and tensile loading. The present study investigates the superelastic deformation behavior under torsion. Using a newly installed torsion testing setup, in situ synchrotron diffraction was carried out on single-crystalline material in order to investigate the martensitic phase transformation. Incremental deformation experiments reveal a fully reversible martensitic transformation under torsional loading at room temperature, leading to excellent strain recovery after deformation to 6.5% shear strain. Furthermore, relevant aspects towards the analysis of powder diffraction data obtained for single-crystalline material in transmission mode under torsional loading are presented and critically discussed.
KW - Shape memory alloy
KW - Pseudoelasticity
KW - Martensitic transformation
KW - Synchrotron diffraction
KW - In situ testing
KW - Torsion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621872
DO - https://doi.org/10.1007/s40830-024-00496-8
VL - 10
SP - 326
EP - 333
PB - Springer Science and Business Media LLC
AN - OPUS4-62187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Runze
A1 - Sur, Debashish
A1 - Li, Kangming
A1 - Witt, Julia
A1 - Black, Robert
A1 - Whittingham, Alexander
A1 - Scully, John R.
A1 - Hattrick-Simpers, Jason
T1 - Bayesian assessment of commonly used equivalent circuit models for corrosion analysis in electrochemical impedance spectroscopy
N2 - Electrochemical Impedance Spectroscopy (EIS) is a crucial technique for assessing corrosion of metallic materials. The analysis of EIS hinges on the selection of an appropriate equivalent circuit model (ECM) that accurately characterizes the system under study. In this work, we systematically examined the applicability of three commonly used ECMs across several typical material degradation scenarios. By applying Bayesian Inference to simulated corrosion EIS data, we assessed the suitability of these ECMs under different corrosion conditions and identified regions where the EIS data lacks sufficient information to statistically substantiate the ECM structure. Additionally, we posit that the traditional approach to EIS analysis, which often requires measurements to very low frequencies, might not be always necessary to correctly model the appropriate ECM. Our study assesses the impact of omitting data from low to medium-frequency ranges on inference results and reveals that a significant portion of low-frequency measurements can be excluded without substantially compromising the accuracy of extracting system parameters. Further, we propose simple checks to the posterior distributions of the ECM components and posterior predictions, which can be used to quantitatively evaluate the suitability of a particular ECM and the minimum frequency required to be measured. This framework points to a pathway for expediting EIS acquisition by intelligently reducing low-frequency data collection and permitting on-the-fly EIS measurements.
KW - Electrochemical Impedance Spectroscopy (EIS)
KW - MAPz@BAM
KW - Bayesian Inference
KW - Corrosion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623392
DO - https://doi.org/10.1038/s41529-024-00537-8
VL - 8
SP - 120
PB - Springer Materials
AN - OPUS4-62339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolff, M.
A1 - Wonneberger, R.
A1 - Freiberg, K.E.
A1 - Hertwig, Andreas
A1 - Bonse, Jörn
A1 - Giebeler, L.
A1 - Koitzsch, A.
A1 - Kunz, C.
A1 - Weber, H.
A1 - Hufenbach, J.K.
A1 - Müller, F.A.
A1 - Gräf, S.
T1 - Formation of laser-induced periodic surface structures on Zr-based bulk metallic glasses with different chemical composition
N2 - Bulk metallic glasses (BMG) are amorphous metal alloys known for their unique physical and mechanical properties. In the present study, the formation of femtosecond (fs) laser-induced periodic surface structures (LIPSS) on the Zr-based BMGs Zr46Cu46Al8, Zr61Cu25Al12Ti2, Zr52.5Cu17.9Al10Ni14.6Ti5 (Vit105) and Zr57Cu15.4Al10Ni12.6Nb5 (Vit106) was investigated as a function of their different chemical composition. For this purpose, LIPSS were generated on the sample surfaces in an air environment by fs-laser irradiation (λ = 1025 nm, τ = 300 fs, frep = 100 kHz). The surface topography was characterized by scanning electron microscopy and atomic force microscopy. Moreover, the impact of LIPSS formation on the structure and chemical surface composition was analyzed before and after fs-laser irradiation by X-ray diffraction and X-ray photoelectron spectroscopy as well as by transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. Despite the different chemical composition of the investigated BMGs, the fs-laser irradiation resulted in almost similar properties of the generated LIPSS patterns. In the case of Zr61Cu25Al12Ti2, Vit105 and Vit106, the surface analysis revealed the preservation of the amorphous state of the materials during fs-laser irradiation. The study demonstrated the presence of a native oxide layer on all pristine BMGs. In addition, fs-laser irradiation results in the formation of laser-induced oxide layers of larger thickness consisting of an amorphous ZrAlCu-oxide. The precise laser-structuring of BMG surfaces on the nanoscale provides a versatile alternative to thermoplastic forming of BMG surfaces and is of particular interest for the engineering of functional material surfaces.
KW - Bulk metallic glasses
KW - Femtosecond laser
KW - Laser-induced periodic surface structures (LIPSS)
KW - Chemical analysis
KW - Oxidation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581799
DO - https://doi.org/10.1016/j.surfin.2023.103305
SN - 2468-0230
VL - 42
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-58179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Porta-Velilla, L.
A1 - Martínez, E.
A1 - Frechilla, A.
A1 - Castro, M.
A1 - de la Fuente, G. F.
A1 - Bonse, Jörn
A1 - Angurel, L. A.
T1 - Grain orientation, angle of incidence, and beam polarization effects on ultraviolet 300 ps-laser-induced nanostructures on 316L stainless steel
N2 - Laser-induced periodic surface structures (LIPSS) represent a unique route for functionalizing materials through the fabrication of surface nanostructures. Commercial AISI 316L stainless steel (SS316L) surfaces are laser treated by ultraviolet 300 ps laser pulses in a laser line scanning (LLS) approach. Processing parameters are optimized (pulse energy of 2.08 µJ, pulse repetition frequency of 300 kHz, and suitable laser scan and sample displacement rates) for the generation of low spatial frequency LIPSS over a large 25 × 25 mm2 area. Different angles of incidence of the laser radiation (0°, 30°, and 45°) and different linear laser beam polarizations (s and p) produce a plethora of rippled surface morphologies at distinct grains. Scanning electron microscopy and 2D Fourier transforms, together with calculations of the optical energy deposited at the treated surfaces using Sipe's first-principles electromagnetic scattering theory, are used to study and analyze in detail these surface morphologies. Combined with electron backscattering diffraction, analyses allow associating site-selectively various laser-induced-surface morphologies with the underlying crystalline grain orientation. Resulting grain orientation maps reveal a strong impact of the grain crystallographic orientation on LIPSS formation and point toward possible strategies, like multi-step processes, for improving the manufacturing of LIPSS and their areal coverage of polycrystalline technical materials.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Steel
KW - Grain orientation
KW - Electron backscattering diffraction (EBSD)
KW - Laser processing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588929
DO - https://doi.org/10.1002/lpor.202300589
SN - 1863-8899
SP - 1
EP - 21
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-58892
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krauklis, A. E.
A1 - Starovka, O.
A1 - Gibhardt, D.
A1 - Aouissi, H. A.
A1 - Burlakovs, J.
A1 - Sabalina, A.
A1 - Fiedler, Bodo
A1 - Kalinka, Gerhard
T1 - Reversible and irreversible effects on the epoxy GFRP fiber-matrix interphase due to hydrothermal aging
N2 - Epoxy R-Glass Fiber-Reinforced Polymer (GFRP) composite plates were hydrothermally aged at 60 ◦C for 23, 75, and 133 days. The water content reached 0.97 wt%, 1.45 wt% and 1.63 wt%, respectively. The studied GFRP matrix was inert to hydrolysis or chain scission, allowing for investigation of irreversible changes in the fiber-matrix interphase due to hydrothermal aging upon re-drying. During each period, a subset of the specimens was removed from the water bath and dried in a chamber. The weight loss upon drying was explained with epoxy leaching (impurities), sizing-rich interphase hydrolysis, glass fiber surface hydrolysis, accumulated degradation products escaping, and water changing state from bound to free. The influence of hydrothermal aging on the fiber-matrix interfacial properties was investigated. Lower interfacial strength of hydrothermally aged (wet)
samples was attributed to plasticization of the epoxy, plasticization and degradation of the sizing-rich interphase (including formation of hydrolytic flaws), and hydrolytic degradation of the glass fiber surface. The kinetics of epoxy-compatible epoxysilane W2020 sizing-rich interphase hydrolysis provided an estimate of ca. 1.49%, 4.80%, and 8.49% of the total composite interphase degraded after 23, 75, and 133 days, respectively. At these conditions, the interface lost 39%, 48%, and 51% of its strength. Upon re-drying the specimens, a significant part of the interfacial strength was regained. Furthermore, an upward trend was observed, being 13%, 10% and 3% strength, respectively; thus, indicating a possibility of partial recovery of properties.
KW - GFRP
KW - Hydrothermal Ageging
KW - Interphase
KW - Water Diffusion
KW - Desorption
KW - Interfacial Strength
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581554
DO - https://doi.org/10.1016/j.jcomc.2023.100395
SN - 2666-6820
VL - 12
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-58155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nandish, Ranjith
A1 - Knaust, Christian
A1 - Zehfuß, Jochen
T1 - Numerical Investigations of a Large Fire Exposure Crib Test—Presenting Different Pyrolysis Modelling Methodologies and Numerical Results
N2 - ABSTRACTThe need for numerical‐based approaches to investigate the fire behaviour in buildings with combustible components is growing due to the increasing use of timber by the construction industry to meet the ‘Climate Action Plan 2050’. This requires consideration of the complex kinetic processes that take place during the burning of the wood in the numerical models. This is accomplished by using computational fluid dynamics (CFD) to numerically model the material pyrolysis and combustion processes. This article presents three different approaches for simulating the behaviour of a wood crib fire using the fire dynamics simulator (FDS). These approaches are based on either prescribing the burning rate of the wood directly from the physical experiments or using the kinetic parameters to govern the underlying processes, such as pyrolysis. Wooden crib fire experiments carried out by the RISE Research Institute in Sweden inside the combustion chamber that were used to validate all the methods. The numerical results from the method, that utilised the experimentally determined burning rate, were in good agreement with the experimental results, with a maximum deviation of 6% in the case of HRR. On the other hand, the model that needs kinetic parameters as its input has shown maximum discrepancies of 12% and 33% compared to experimental results. These methods are sensitive to the input parameters and the extent of dependency needs further investigation.
KW - Pyrolysis
KW - Wood combustion
KW - Wood fire loads
KW - Wooden buildings
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626567
DO - https://doi.org/10.1002/fam.3287
SN - 1099-1018
VL - 49
IS - 4
SP - 371
EP - 387
PB - John Wiley & Sons Ltd.
AN - OPUS4-62656
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Krebber, Katerina
T1 - Machine Learning Approaches in Brillouin Distributed Fiber Optic Sensors
N2 - This paper presents reported machine learning approaches in the field of Brillouin distributed fiber optic sensors (DFOSs). The increasing popularity of Brillouin DFOSs stems from their capability to continuously monitor temperature and strain along kilometer-long optical fibers, rendering them attractive for industrial applications, such as the structural health monitoring of large civil infrastructures and pipelines. In recent years, machine learning has been integrated into the Brillouin DFOS signal processing, resulting in fast and enhanced temperature, strain, and humidity measurements without increasing the system’s cost. Machine learning has also contributed to enhanced spatial resolution in Brillouin optical time domain analysis (BOTDA) systems and shorter measurement times in Brillouin optical frequency domain analysis (BOFDA) systems. This paper provides an overview of the applied machine learning methodologies in Brillouin DFOSs, as well as future perspectives in this area.
KW - Distributed fiber optic sensors
KW - BOTDA
KW - BOFDA
KW - Machine learning
KW - Strain and temperature measurements
KW - Artificial neural networks
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580145
DO - https://doi.org/10.3390/s23136187
VL - 23
IS - 13
SP - 1
EP - 26
PB - MDPI
AN - OPUS4-58014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Machine learning assisted BOFDA for simultaneous temperature and strain sensing in a standard optical fiber
N2 - We report, to our knowledge for the first time on simultaneous distributed temperature and strain sensing in a standard telecom optical fiber using a machine learning assisted Brillouin frequency domain analysis (BOFDA) system. The well-known temperature and strain cross-sensitivity problem is addressed by developing a BOFDA system with a high signal-to-noise ratio and applying machine learning. The spectrum consists of four highly resolved peaks, whose Brillouin frequency shifts are extracted and serve as features for the machine learning algorithms. The spectra result from a 450-m standard SMF-28 optical fiber, and particularly from a segment of 30 m. This fiber segment is coiled around a stretcher and placed in a climate chamber. The applied temperature and strain values range from 20 °C to 40 °C and from 0 µɛ to 1380 µɛ, respectively. The total measurement time to achieve a high SNR and resolve four peaks with a spatial resolution of 6 m is 16 min. To discriminate temperature and strain effects, simple frequentist and more sophisticated Bayesian-based algorithms are employed with the powerful Gaussian process regression (GPR) delivering the best performance in terms of temperature and strain errors, which are found to be 2 °C and 45 µɛ, respectively. These errors are calculated using leave-one-out cross-validation, so that an unbiased estimation of the sensor’s performance is provided.
KW - Machine learning
KW - Brillouin distributed fiber optic sensors
KW - Temperature and strain sensing
KW - BOFDA
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569155
DO - https://doi.org/10.1364/OE.480224
SN - 1094-4087
VL - 31
IS - 3
SP - 5027
EP - 5041
PB - OPTICA
AN - OPUS4-56915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Wosniok, Aleksander
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Time-Efficient Convolutional Neural Network-Assisted Brillouin Optical Frequency Domain Analysis
N2 - To our knowledge, this is the first report on a machine-learning-assisted Brillouin optical frequency domain analysis (BOFDA) for time-efficient temperature measurements. We propose a convolutional neural network (CNN)-based signal post-processing method that, compared to the conventional Lorentzian curve fitting approach, facilitates temperature extraction. Due to its robustness against noise, it can enhance the performance of the system. The CNN-assisted BOFDA is expected to shorten the measurement time by more than nine times and open the way for applications, where faster monitoring is essential.
KW - Fiber-optic sensors
KW - Machine learning
KW - Temperature and strain monitoring
KW - Brillouin distributed sensing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524631
DO - https://doi.org/10.3390/s21082724
VL - 21
IS - 8
SP - 2724
PB - MDPI
AN - OPUS4-52463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Hicke, Konstantin
A1 - Wosniok, Aleksander
A1 - Krebber, Katerina
T1 - Distributed humidity fiber-optic sensor based on BOFDA using a simple machine learning approach
N2 - We report, to our knowledge for the first time, on distributed relative humidity sensing in silica polyimide-coated optical fibers using Brillouin optical frequency domain analysis (BOFDA). Linear regression, which is a simple and well-interpretable algorithm in machine learning and statistics, is utilized. The algorithm is trained using as features the Brillouin frequency shifts and linewidths of the fiber’s multipeak Brillouin spectrum. To assess and improve the effectiveness of the regression algorithm, we make use of machine learning concepts to estimate the model’s uncertainties and select the features that contribute most to the model’s performance. In addition to relative humidity, the model is also able to simultaneously provide distributed temperature information addressing the well-known cross-sensitivity effects.
KW - Fiber optics sensors
KW - Machine learning
KW - Brillouin distributed sensing
KW - Humidity sensing
KW - Simultaneous temperature and humidity sensing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546294
DO - https://doi.org/10.1364/OE.453906
VL - 30
IS - 8
SP - 12484
EP - 12494
PB - OPTICA
AN - OPUS4-54629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martin, T.
A1 - Zimmermann, E.
A1 - Klitzsch, N.
A1 - Hördt, A.
A1 - Huisman, J. A.
A1 - Radic, T.
A1 - Kruschwitz, Sabine
T1 - Round-robin test of SIP laboratory measurements using electrical test networks
N2 - This study presents the results of an interlaboratory test designed to evaluate the accuracy of spectral induced polarization (SIP) measurements using controlled electrical test networks. The study, conducted in Germany since 2006, involved 12 research institutes, six different impedance measurement devices and four types of electrical test networks specifically designed to evaluate phase shift errors in SIP measurements. The test networks, with impedances ranging from 100 to 150 kΩ, represent high-impedance samples with different phase characteristics, and pose the measurement challenges typical of such samples, including high contact impedances and parasitic capacitances. Four key findings emerged from the study: (1) Impedance measurements across all devices showed deviations within 1 per cent over a wide frequency range (0.001–1000 Hz); (2) phase errors remained below 1 mrad up to 100 Hz for most devices, but increased at higher frequencies due to parasitic capacitances and electromagnetic coupling effects; (3) lab-specific instruments have lower phase errors than field instruments when used in a laboratory environment, primarily due to the effects of long cables and too low input impedances of the field instruments; and (4) short cables and driven shielding technology effectively minimized parasitic capacitance and improved measurement accuracy. The study highlights the usefulness of test networks in assessing the accuracy of SIP measurements and raises awareness of the various factors influencing the quality of SIP data.
KW - Induced polarization
KW - Electrical properties
KW - Electrical resistivity tomography (ERT)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631522
DO - https://doi.org/10.1093/gji/ggaf153
SN - 0956-540X
VL - 242
IS - 1
SP - 1
EP - 13
PB - Oxford University Press (OUP)
AN - OPUS4-63152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Milks, A.
A1 - Lehmann, J.
A1 - Leder, D.
A1 - Sietz, M.
A1 - Koddenberg, T.
A1 - Böhner, U.
A1 - Wachtendorf, Volker
A1 - Terberger, T.
T1 - A double-pointed wooden throwing stick from Schöningen, Germany: Results and new insights from a multianalytical study
N2 - The site of Schöningen (Germany), dated to ca. 300,000 years ago, yielded the earliest large-scale record of humanly-made wooden tools. These include wooden spears and shorter double-pointed sticks, discovered in association with herbivores that were hunted and butchered along a lakeshore. Wooden tools have not been systematically analysed to the same standard as other Palaeolithic technologies, such as lithic or bone tools. Our multianalytical study includes micro-CT scanning, 3-dimensional microscopy, and Fourier transform infrared spectroscopy, supporting a systematic technological and taphonomic analysis, thus setting a new standard for wooden tool analysis. In illustrating the biography of one of Schöningen’s double-pointed sticks, we demonstrate new human behaviours for this time period, including sophisticated woodworking techniques. The hominins selected a spruce branch which they then debarked and shaped into an aerodynamic and ergonomic tool. They likely seasoned the wood to avoid cracking and warping. After a long period of use, it was probably lost while hunting, and was then rapidly buried in mud. Taphonomic alterations include damage from trampling, fungal attack, root damage and compression. Through our detailed analysis we show that Middle Pleistocene humans had a rich awareness of raw material properties, and possessed sophisticated woodworking skills. Alongside new detailed morphometrics of the object, an ethnographic review supports a primary function as a throwing stick for hunting, indicating potential hunting strategies and social contexts including for communal hunts involving children. The Schöningen throwing sticks may have been used to strategically disadvantage larger ungulates, potentially from distances of up to 30 metres. They also demonstrate that the hominins were technologically capable of capturing smaller fast prey and avian fauna, a behaviour evidenced at contemporaneous Middle Pleistocene archaeological sites.
KW - FTIR
KW - Stone Age
KW - Middle Pleistocene
KW - Throwing-stick
KW - Wood
KW - Micro-CT scanning
KW - 3-dimensional microscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580012
DO - https://doi.org/10.1371/journal.pone.0287719
SN - 1932-6203
VL - 18
IS - 7
SP - 1
EP - 32
PB - PLOS
CY - San Francisco, California, US
AN - OPUS4-58001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pirker, F.
A1 - Toth, I.
A1 - Cihak-Bayr, U.
A1 - Grundtner, R.
A1 - Vernes, A.
A1 - Benedicto, J.
A1 - Spaltmann, Dirk
A1 - Gradt, Thomas
A1 - Alberdi, A.
A1 - Alonso, I.
A1 - Bayón, R.
A1 - Igartua, A.
A1 - García, Á.
A1 - Pagano, F.
A1 - Bravo, I.
A1 - Kogia, M.
A1 - Dykeman, D.
A1 - Liedtke, S.
A1 - Minami, I.
A1 - Nyberg, E.
A1 - Soivio, K.
A1 - Ronkainen, H.
A1 - Majaniemi, S.
A1 - Heino, V.
A1 - Gkagkas, K.
A1 - Mont, L.
A1 - Amigorena, I.
T1 - Tribological characterisation services for materials - i-TRIBOMAT
N2 - Um den Entwicklungsprozess von neuen Komponenten zu beschleunigen, ist die Vorrausage der Eigenschaften der eingesetzten Werkstoffe im Betrieb der Komponenten von enormer Bedeutung. Um neue Werkstoffe hinsichtlich Ihrer Performance (in einer Komponente) bewerten zu können, ist deshalb die Entwicklung neuer innovativer Methoden notwendig. Diese Methoden können auch unter dem Begriff „lab-to-field“ oder „materials“ – up-scaling zusammengefasst werden. D. h. Werkstoffe werden im Labor charakterisiert, und deren Eigenschaften mittels z.B. Simulation auf die Komponentenperformance hochskaliert (upscaling). i-TRIBOMAT ist ein EU gefördertes Projekt (H2020, GA Nr. 814494) mit dem Ziel ein Open Innovation Test Bed für tribologische Werkstoffcharakterisierung aufzubauen und entsprechende Services von der tribologischen Charakterisierung neuer Werkstoffe bis hin zu Simulationsmodellen zur Vorrausage der Perfomance von Komponenten der Industrie anzubieten. Durch die Bündelung von Knowhow und Infrastruktur zu Charakterisierung sowie den Aufbau einer digitalen Plattform, wird i-TRIBOMAT das weltgrößte Open Innovation Test Bed für tribologische Werkstoffcharakterisierung.
N2 - The prediction of the properties of the materials used in the operation of components is of enormous importance, in order to accelerate the development process of new components. To evaluate new materials in terms of their performance (in a component), the development of new innovative methods is necessary. These methods can also be summarized under the term lab-to-field or materials – upscaling, meaning materials being characterised in a laboratory and their properties being upscaled to the component performance by means of e.g. simulation. i-TRIBOMAT is a EU funded project (H2020, GA Nr. 814494) aiming at building an Open Innovation Test Bed for tribological material characterization and offering corresponding services from tribological characterization of new materials to simulation models for predicting the performance of industrial components. By bundling the infrastructure, know-how for characterization and building a digital platform, i-TRIBOMAT becomes the world’s largest open innovation test bed for tribological material characterization.
T2 - 22nd International Colloquium Tribology
CY - Esslingen, Germany
DA - 28.01.2020
KW - Tribologie
KW - Lab-to-field up-scaling
KW - Werkstoffdatenbank
KW - Geteilte Infrastruktur
KW - Tribo-Analytik
KW - Intelligente tribologische Werkstoffcharakterisierung
KW - Lab-to-field upscaling
KW - Tribology
KW - Intelligent tribological material characterization
KW - Materials database
KW - Shared infrastruture
KW - Tribo-analytics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576762
DO - https://doi.org/10.30419/TuS-2020-0026
SN - 0724-3472
SN - 2941-0908
VL - 67
IS - 5-6
SP - 35
EP - 50
PB - Expert
CY - Tübingen
AN - OPUS4-57676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hering, Marcus
A1 - Sievers, Jürgen
A1 - Curbach, Manfred
A1 - Beckmann, Birgit
T1 - An Approach to Predicting the Ballistic Limit of Thin Textile-Reinforced Concrete Plates Based on Experimental Results
N2 - In this article, a partial selection of experiments on enhancing the impact resistance of structural components with non-metallic, textile-reinforced concrete is discussed. The focus is on the experimental investigations in which the impact resistance of thin, textile-reinforced concrete plates is characterized. The article discusses the materials, fabrics and test setup used. For the experimental work, a drop tower from the Otto Mohr Laboratory, which belongs to the Technische Universtät Dresden, was used. Furthermore, the experimental results are presented and evaluated using different methods. Based on the collected data, a suitable approach to determining the perforation velocity of an impactor through the investigated thin, textile-reinforced concrete plates is shown.
KW - Building and Construction
KW - Civil and Structural Engineering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586692
DO - https://doi.org/10.3390/buildings13092234
VL - 13
IS - 9
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-58669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brockmann, N.
A1 - Sicken, A.
A1 - Krüger, Jörg
T1 - Effects of laser cleaning on the condition of different silk model samples using varying wavelengths and pulse durations
N2 - The cleaning of aged silk fibers poses a common challenge in the conservation of textiles, since traditional cleaning techniques often yield unsatisfactory results or even harm objects. In this regard, cleaning objects with laser radiation is a promising addition to the range of available methods. Due to it being contactless, even brittle and touch-sensitive objects with disfiguring or harmful soiling could potentially be cleaned and therefore made accessible for research and presentation. Examples of treatment have sometimes shown spectacular results. Still there is some skepticism concerning the safety of this treatment for textile materials, which has been strengthened through previous 532 nm wavelength nanosecond laser cleaning studies on silk fibers. Taking these published results into account, the range of examined laser parameters has been extended in this study, from 532 nm nanosecond laser to 1064 nm nanosecond and even 800 nm femtosecond laser, reevaluating the effect of this treatment on the fibers. The physicochemical processes taking place on the silk fibers when cleaning with lasers are complex and still not fully understood. The aim of this project was therefore to bring more clarification about potential effects of those processes on the condition of silk samples treated with a set of different parameters for wavelength, pulse duration, energy density and number of pulses per spot. It also looks at the influence of the presence of soiling on the results. The analysis of potential effects was then carried out using statistical methods and advanced analytics. Scanning electron microscopy, Fourier-transform infrared spectroscopy and colorimetry technology provided the required insights to better assess the effects. Results show that laser cleaning of silk fibers, like most other conventional cleaning techniques, is not completely without risk, but knowing what the possible effects are helps making decisions on whether the benefits of the technique used justify these risks.
KW - Laser cleaning
KW - Cultural heritage
KW - Conservation
KW - Silk
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594601
DO - https://doi.org/10.1186/s40494-024-01152-1
SN - 2050-7445
VL - 12
IS - 1
SP - 1
EP - 15
PB - Springer
AN - OPUS4-59460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Was, G.S.
A1 - Bahn, C.-B.
A1 - Busby, J.
A1 - Cui, B.
A1 - Farkas, D.
A1 - Gussev, M.
A1 - Rigen He, M.
A1 - Hesterberg, J.
A1 - Jiao, Z.
A1 - Johnson, D.
A1 - Kuang, W.
A1 - McMurtrey, M.
A1 - Robertson, I.
A1 - Sinjlawi, A.
A1 - Song, M.
A1 - Stephenson, K.
A1 - Sun, K.
A1 - Swaminathan, Srinivasan
A1 - Wang, M.
A1 - West, E.
T1 - How irradiation promotes intergranular stress corrosion crack initiation
N2 - Irradiation assisted stress corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide.
KW - Irradiation
KW - Stress corrosion cracking
KW - Grain boundaries
KW - Oxidation
KW - Austenitic alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595748
DO - https://doi.org/10.1016/j.pmatsci.2024.101255
SN - 0079-6425
VL - 143
SP - 1
EP - 15
PB - Elsevier
AN - OPUS4-59574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Minenkov, Alexey
A1 - Hollweger, Sophia
A1 - Duchoslav, Jiri
A1 - Erdene-Ochir, Otgonbayar
A1 - Weise, Matthias
A1 - Ermilova, Elena
A1 - Hertwig, Andreas
A1 - Schiek, Manuela
T1 - Monitoring the Electrochemical Failure of Indium Tin Oxide Electrodes via Operando Ellipsometry Complemented by Electron Microscopy and Spectroscopy
N2 - Transparent conductive oxides such as indium tin oxide (ITO) are standards for thin film electrodes, providing a synergy of high optical transparency and electrical conductivity. In an electrolytic environment, the determination of an inert electrochemical potential window is crucial to maintain a stable material performance during device operation. We introduce operando ellipsometry, combining cyclic voltammetry (CV) with spectroscopic ellipsometry, as a versatile tool to monitor the evolution of both complete optical (i.e., complex refractive index) and electrical properties under wet electrochemical operational conditions. In particular, we trace the degradation of ITO electrodes caused by electrochemical reduction in a pH-neutral, water-based electrolyte environment during electrochemical cycling. With the onset of hydrogen evolution at negative bias voltages, indium and tin are irreversibly reduced to the metallic state, causing an advancing darkening, i.e., a gradual loss of transparency, with every CV cycle, while the conductivity is mostly conserved over multiple CV cycles. Post-operando analysis reveals the reductive (loss of oxygen) formation of metallic nanodroplets on the surface. The reductive disruption of the ITO electrode happens at the solid–liquid interface and proceeds gradually from the surface to the bottom of the layer, which is evidenced by cross-sectional transmission electron microscopy imaging and complemented by energy-dispersive X-ray spectroscopy mapping. As long as a continuous part of the ITO layer remains at the bottom, the conductivity is largely retained, allowing repeated CV cycling. We consider operando ellipsometry a sensitive and nondestructive tool to monitor early stage material and property changes, either by tracing failure points, controlling intentional processes, or for sensing purposes, making it suitable for various research fields involving solid–liquid interfaces and electrochemical activity.
KW - General Materials Science
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597625
DO - https://doi.org/10.1021/acsami.3c17923
SN - 1944-8252
VL - 16
IS - 7
SP - 9517
EP - 9531
PB - American Chemical Society (ACS)
AN - OPUS4-59762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knapic, D.
A1 - Mardare, A. I.
A1 - Voss, Heike
A1 - Bonse, Jörn
A1 - Hassel, A. W.
T1 - Corrosion study of picosecond-laser structured and anodized Ti6Al4V for bone screws
N2 - A corrosion study is performed on six variations of titanium grade 5 (Ti6Al4V) samples. Samples are prepared in different conditions by variation of preanodization, postanodization, and picosecond-laser (ps-laser) surface treatment, while polished and anodized samples serve as reference. Microcones and nanosized periodic surface features are successfully produced on Ti6Al4V samples. The morphology and topography of the structures are visualized by scanning electron microscopy and white light interference microscopy. Furthermore, the relative electrochemically active surface area (ECSA) is determined for the ps-laser-treated samples. It is determined that the preanodized and laser-treated sample has 3.5 times larger ECSA than a polished sample, and that the laser-treated sample has 4.1 times larger area. Moreover, Tafel analysis is performed to determine the corrosion properties of the samples. It is shown that the corrosion resistance improves for both laser-structured samples after the anodization. To further study the surface of the samples, electrochemical impedance spectroscopy measurements are conducted. The study indicates that the ps-laser-treated and anodized Ti6Al4V is suitable to be used for the fabrication of bone screws and plates due to its improved corrosion resistance as compared to nonanodized samples.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Anodization
KW - Bone screws
KW - Implant material
KW - Titanium alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597890
DO - https://doi.org/10.1002/pssa.202300609
SN - 1862-6319
VL - 221
SP - 1
EP - 8
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-59789
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nawaz, Q.
A1 - Blaeß, Carsten
A1 - Mueller, Ralf
A1 - Boccaccini, A.R.
T1 - Processing and cytocompatibility of Cu-doped and undoped fluoride-containing bioactive glasses
N2 - Sintered or additive-manufactured bioactive glass (BG) scaffolds are highly interesting for bone replacement applications. However, crystallization often limits the high-temperature processability of bioactive glasses (BGs). Thus, the BG composition must combine high bioactivity and processability. In this study, three BGs with nominal molar (%) compositions 54.6SiO2-1.7P2O3-22.1CaO-6.0Na2O-7.9K2O-7.7MgO (13–93), 44.8SiO2-2.5P2O3-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2 (F3) and 44.8SiO2-2.5P2O3-35.5CaO-6.6Na2O-6.6K2O-3.0CaF2-1.0CuO (F3–Cu) were investigated. The dissolution and ion release kinetics were investigated on milled glass powder and crystallized particles (500–600 μm). All glasses showed the precipitation of hydroxyapatite (HAp) crystals after 7 days of immersion in simulated body fluid. No significant differences in ion release from glass and crystalline samples were detected. The influence of surface roughness on cytocompatibility and growth of preosteoblast cells (MC3T3-E1) was investigated on sintered and polished BG pellets. Results showed that sintered BG pellets were cytocompatible, and cells were seen to be well attached and spread on the surface after 5 days of incubation. The results showed an inverse relation of cell viability with the surface roughness of pellets, and cells were seen to attach and spread along the direction of scratches.
KW - Bioactive glass
KW - Crystallization
KW - Solubility
KW - Cytocompatibility
KW - Surface roughness
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598257
DO - https://doi.org/10.1016/j.oceram.2024.100586
SN - 2666-5395
VL - 18
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-59825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
T1 - Semantic integration of diverse data in materials science: Assessing Orowan strengthening
N2 - AbstractThis study applies Semantic Web technologies to advance Materials Science and Engineering (MSE) through the integration of diverse datasets. Focusing on a 2000 series age-hardenable aluminum alloy, we correlate mechanical and microstructural properties derived from tensile tests and dark-field transmission electron microscopy across varied aging times. An expandable knowledge graph, constructed using the Tensile Test and Precipitate Geometry Ontologies aligned with the PMD Core Ontology, facilitates this integration. This approach adheres to FAIR principles and enables sophisticated analysis via SPARQL queries, revealing correlations consistent with the Orowan mechanism. The study highlights the potential of semantic data integration in MSE, offering a new approach for data-centric research and enhanced analytical capabilities.
KW - Semantic Interoperability
KW - Knowledge Graph
KW - Orowan Mechanism
KW - Aluminum Alloy Aging
KW - Ontology
KW - Semantic Data Integration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599780
DO - https://doi.org/10.1038/s41597-024-03169-4
VL - 11
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-59978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ratkovac, Mirjana
A1 - Gerards-Wünsche, Paul
A1 - Thiele, Marc
A1 - Brackrock, Daniel
A1 - Stamm, Michael
T1 - Detection and monitoring of the fatigue crack growth on welds – Application-oriented use of NDT methods
N2 - Early detection of fatigue cracks and accurate measurements of the crack growth play an important role in the maintenance and repair strategies of steel structures exposed to cyclic loads during their service life. Observation of welded connections is especially of high relevance due to their higher susceptibility to fatigue damage. The aim of this contribution was to monitor fatigue crack growth in thick welded specimens during fatigue tests as holistically as possible, by implementing multiple NDT methods simultaneously in order to record the crack initiation and propagation until the final fracture. In addition to well-known methods such as strain gauges, thermography, and ultrasound, the crack luminescence method developed at the Bundesanstalt für Materialforschung und -prüfung (BAM), which makes cracks on the surface particularly visible, was also used. For data acquisition, a first data fusion concept was developed and applied in order to synchronize the data of the different methods and to evaluate them to a large extent automatically. The resulting database can ultimately also be used to access, view, and analyze the experimental data for various NDT methods. During the conducted fatigue tests, the simultaneous measurements of the same cracking process enabled a comprehensive comparison of the methods, highlighting their individual strengths and limitations. More importantly, they showed how a synergetic combination of different NDT methods can be beneficial for implementation in large-scale fatigue testing but also in monitoring and inspection programs of in-service structures - such as the support structures of offshore wind turbines.
T2 - Fatigue Design 2023 (FatDes 2023)
CY - Senlis, France
DA - 29.11.2023
KW - Fatigue
KW - Welded
KW - NDT
KW - Crack growth
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600238
DO - https://doi.org/10.1016/j.prostr.2024.03.062
VL - 57
SP - 560
EP - 568
PB - Elsevier B.V.
AN - OPUS4-60023
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grundmann, Jana
A1 - Bodermann, Bernd
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - Hertwig, Andreas
A1 - Klapetek, Petr
A1 - Rafighdoost, Jila
A1 - Pereira, Silvania F.
T1 - Optical and tactile measurements on SiC sample defects
N2 - Abstract. In power electronics, compound semiconductors with large bandgaps, like silicon carbide (SiC), are increasingly being used as material instead of silicon. They have a lot of advantages over silicon but are also intolerant of nanoscale material defects, so that a defect inspection with high accuracy is needed. The different defect types on SiC samples are measured with various measurement methods, including optical and tactile methods. The defect types investigated include carrots, particles, polytype inclusions and threading dislocations, and they are analysed with imaging ellipsometry, coherent Fourier scatterometry (CFS), white light interference microscopy (WLIM) and atomic force microscopy (AFM). These different measurement methods are used to investigate which method is most sensitive for which type of defect to be able to use the measurement methods more effectively. It is important to be able to identify the defects to classify them as critical or non-critical for the functionality of the end product. Once these investigations have been completed, the measurement systems can be optimally distributed to the relevant defects in further work to realize a hybrid analysis of the defects. In addition to the identification and classification of defects, such a future hybrid analysis could also include characterizations, e.g. further evaluation of ellipsometric data by using numerical simulations.
KW - Compound semiconductors
KW - Hybrid metrology
KW - Material defects
KW - Spectroscopic ellipsometry
KW - Scanning probe microscopy
KW - White-light interference microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601220
DO - https://doi.org/10.5194/jsss-13-109-2024
SN - 2194-878X
VL - 13
IS - 1
SP - 109
EP - 121
PB - Copernicus Publ.
CY - Göttingen
AN - OPUS4-60122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hashemi, Seyedreza
A1 - Zscherpel, Uwe
T1 - Measurement of Focal Spots of X-ray Tubes Using a CT Reconstruction Approach on Edge Images of Large Holes and Comparison to Pinhole Imaging
N2 - The first Non-destructive testing (NDT) method which evolved in the industrial age was radiographic testing (RT). Among all NDT methods, RT is no exception, so there are still many issues for optimizations even today. One of them is the measurement of the focal spot of X-ray tubes. The size of the focal spot is critical for imaging, because it determines the spatial resolution in the X-ray image. The classical way to evaluate focal spots of X-ray tubes is by pinhole imaging using a camera obscura. But this method has a natural lower limit, which is defined by the diameter of the pinhole used (today min. 10 µm). Therefore, focal spot sizes lower than 50 µm diameter cannot be imaged and measured correctly. An alternative approach, which permits this, was investigated here using the edge unsharpness of holes much larger than the focal spot size. The results of both methods were compared using 3 different X-ray tubes.
KW - Reconstruction method
KW - Radiographic testing (RT) using X-rays
KW - Focal spot measurement
KW - Edge unsharpness
KW - X-ray tubes
KW - Pinhole imaging
KW - Computed Tomography (CT)
KW - Focal Spot (FS)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608646
DO - https://doi.org/10.58286/29556
SN - 2941-4989
SP - 1
EP - 9
PB - NDT.net
CY - Berlin, Germany
AN - OPUS4-60864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - da Costa, P. F. G. M.
A1 - Merízio, L. G.
A1 - Wolff, N.
A1 - Terraschke, H.
A1 - de Camargo, Andrea Simone Stucchi
T1 - Real-time monitoring of CdTe quantum dots growth in aqueous solution
N2 - Quantum dots (QDs) are remarkable semiconductor nanoparticles, whose optical properties are strongly size-dependent. Therefore, the real-time monitoring of crystal growth pathway during synthesis gives an excellent opportunity to a smart design of the QDs luminescence. In this work, we present a new approach for monitoring the formation of QDs in aqueous solution up to 90 °C, through in situ luminescence analysis, using CdTe as a model system. This technique allows a detailed examination of the evolution of their light emission. In contrast to in situ absorbance analysis, the in situ luminescence measurements in reflection geometry are particularly advantageous once they are not hindered by the concentration increase of the colloidal suspension. The synthesized particles were additionally characterized using X-ray diffraction analysis, transition electron microscopy, UV-Vis absorption and infrared spectroscopy. The infrared spectra showed that 3-mercaptopropionic acid (MPA)-based thiols are covalently bound on the surface of QDs and microscopy revealed the formation of CdS. Setting a total of 3 h of reaction time, for instance, the QDs synthesized at 70, 80 and 90 °C exhibit emission maxima centered at 550, 600 and 655 nm. The in situ monitoring approach opens doors for a more precise achievement of the desired emission wavelength of QDs.
KW - CdTe quantum dots
KW - In situ synthesis
KW - Real time growth control
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603596
DO - https://doi.org/10.1038/s41598-024-57810-8
SN - 2045-2322
VL - 14
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-60359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Fengchan
A1 - Oiticica, Pedro Ramon Almeida
A1 - Abad-Arredondo, Jaime
A1 - Arai, Marylyn Setsuko
A1 - Oliveira, Osvaldo N.
A1 - Jaque, Daniel
A1 - Fernandez Dominguez, Antonio I.
A1 - de Camargo, Andrea Simone Stucchi
A1 - Haro-González, Patricia
T1 - Brownian Motion Governs the Plasmonic Enhancement of Colloidal Upconverting Nanoparticles
N2 - Upconverting nanoparticles are essential in modern photonics due to their ability to convert infrared light to visible light. Despite their significance, they exhibit limited brightness, a key drawback that can be addressed by combining them with plasmonic nanoparticles. Plasmon-enhanced upconversion has been widely demonstrated in dry environments, where upconverting nanoparticles are immobilized, but constitutes a challenge in liquid media where Brownian motion competes against immobilization.
This study employs optical tweezers for the three-dimensional manipulation of an individual upconverting nanoparticle, enabling the exploration of plasmon-enhanced upconversion luminescence in water. Contrary to expectation, experiments reveal a long-range (micrometer scale) and moderate (20%) enhancement in upconversion luminescence due to the plasmonic resonances of gold nanostructures. Comparison between experiments and numerical simulations evidences the key role of Brownian motion. It is demonstrated how the three-dimensional Brownian fluctuations of the upconverting nanoparticle lead to an “average effect” that explains the magnitude and spatial extension of luminescence enhancement.
KW - Upconversion
KW - Plasmon enhancement
KW - Optical tweezers
KW - Brownian motion
KW - Nanoparticles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603551
DO - https://doi.org/10.1021/acs.nanolett.4c00379
VL - 24
IS - 12
SP - 3785
EP - 3792
PB - American Chemical Society (ACS)
AN - OPUS4-60355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Held, Mathias
A1 - Bulling, Jannis
A1 - Lugovtsova, Yevgeniya
A1 - Prager, Jens
T1 - Determination of isotropic elastic constants from dispersion images based on ultrasonic guided waves by using neural networks
N2 - This article presents a method to use the dispersive behavior of ultrasonic guided waves and neural networks to determine the isotropic elastic constants of plate-like structures through dispersion images. Therefore, two different architectures are compared: one using convolutions and transfer learning based on the EfficientNetB7 and a Vision Transformer-like approach. To accomplish this, simulated and measured dispersion images are generated, where the first is applied to design, train, and validate and the second to test the neural networks. During the training of the neural networks, distinct data augmentation layers are employed to introduce artifacts appearing in measurement data into the simulated data. The neural networks can extrapolate from simulated to measured data using these layers. The trained neural networks are assessed using dispersion images from seven known material samples. Multiple variations of the measured dispersion images are tested to guarantee the prediction stability. The study demonstrates that neural networks can learn to predict the isotropic elastic constants from measured dispersion images using only simulated dispersion images for training and validation without needing an initial guess or manual feature extraction, independent of the measurement setup. Furthermore, the suitability of the different architectures for generating information from dispersion images in general is discussed.
KW - Ultrasonic guided waves
KW - Dispersion
KW - Elastic constants
KW - Neural networks
KW - Image processing
KW - Vision transformer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607090
DO - https://doi.org/10.1016/j.ultras.2024.107403
SN - 0041-624X
VL - 143
SP - 1
EP - 48
PB - Elsevier B.V.
AN - OPUS4-60709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulrich, A. S.
A1 - Kasatikov, S.
A1 - König, T.
A1 - Fantin, Andrea
A1 - Margraf, J. T.
A1 - Galetz, M. C.
T1 - Decreased Metal Dusting Resistance of Ni-Cu Alloys by Fe and Mn Additions
N2 - Ni-Cu alloys are promising for application at temperatures between 400–900 °C and reducing atmospheres with high C-contents. Typically, under such conditions, metallic materials in contact with the C-rich atmosphere are degraded by a mechanism called metal dusting (MD). Ni-Cu-alloys do not form protective oxide scales, but their resistance is attributed to Cu, which catalytically inhibits the C-deposition on the surface. Adding other alloying elements, such as Mn or Fe, was found to enhance the MD attack of Ni-Cu alloys again. In this study, the effect of the Mn and Fe is divided into two affected areas: the surface and the bulk. The MD attack on binary Ni-Cu alloys, model alloys with Fe and Mn additions, and commercial Monel Alloy 400 is experimentally demonstrated. The surface electronic structure causing the adsorption and dissociation of C-containing molecules is investigated for model alloys. Analytical methods such as scanning electron microscopy combined with energy-dispersive X-ray spectroscopy, electron probe microanalysis combined with wavelength-dispersive X-ray spectroscopy, X-ray diffraction analysis, and near-edge X-ray absorption fine structure measurements were used. The results are correlated to CALPHAD calculations and atomistic simulations combining density functional theory calculations and machine learning. It is found that the Cu content plays a significant role in the surface reaction. The effect of Mn and Fe is mainly attributed to oxide formation. A mechanism explaining the enhanced attack by adding both Fe and Mn is proposed.
KW - Metal Dusting
KW - XANES
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608226
DO - https://doi.org/10.1007/s11085-024-10263-w
SN - 2731-8397
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-60822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Prager, Jens
A1 - Grzeszkowski, M.
T1 - Online-Überwachung des Bauteilzustandes von Eisenbahn-Radsatzwellen mitels geführter Ultraschallwellen
N2 - Online-Strukturüberwachungssysteme sind eine Möglichkeit, den Anforderungen hinsichtlich Leichtbau und Zuverlässigkeit gleichzeitig gerecht zu werden. Die Integration solcher Systeme liefert aktuelle Informationen über die Integrität der sicherheitsrelevanten Struktur, wodurch sich Aussagen über notwendige Instandhaltungsarbeiten und möglicherweise über die zu erwartende Restlebensdauer ableiten lassen. Der zielgerichtete Einsatz der Überwachungssysteme ermöglicht es somit, die benötigten Sicherheitsfaktoren bei der Auslegung der Bauteile zu reduzieren und Wartungsintervalle zu verlängern. Dadurch können Kosten gesenkt werden, ohne die Zuverlässigkeit zu verringern. Im Rahmen einer Studie zur Machbarkeit eines Online-Überwachungssystems für Eisenbahn-Radsatzwellen wurde der Einsatz geführter Ultraschallwellen, die von Sensoren an einer Stirnseite der Wellen angeregt werden, demonstriert. Aufgrund der Bauteilgeometrie und der dispersiven, multimodalen Wellenausbreitung stellt die Interpretation der Echosignale eine wesentliche Herausforderung dar. Basierend auf dem a-priori-Wissen über die Wellenausbreitung wurden in der Studie klassifizierende Auswertealgorithmen entwickelt und erfolgreich an maßstabsgetreuen Labormodellen getestet.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Strukturüberwachung
KW - Ultraschallprüfung
KW - Zerstörungsfreie Prüfung
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331931
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Poster 61, 1
EP - 2
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-33193
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stoycheva, V.
A1 - Goering, Harald
A1 - Wolff, Dietmar
A1 - Herzog, M.
T1 - Bestimmung der Kohäsionsenergie- und Vernetzungsdichte von Polymeren mit Hilfe von Quellungsmessungen
N2 - Bei der Abschätzung der Beständigkeit von Kunststoffen gegenüber niedermolekularen Flüssigkeiten ist die Kohäsionsenergiedichte CED ein wichtiger Parameter auf molekularer Ebene. Die Vernetzungsdichte ν eines polymeren Festkörpers bildet hierbei einen bedeutsamen Kennwert, der darüber hinaus neben der Löslichkeit wichtige Eigenschaften wie thermische Stabilität und Steifigkeit des Materials charakterisiert. Für die experimentelle Bestimmung von CED und ν eignet sich die Untersuchung des Quellverhaltens in unterschiedlichen Lösungsmitteln. Es werden zwei Messmethoden miteinander verglichen und die Ergebnisse unter Berücksichtigung des molekularen Aufbaus von Proben aus Polyurethan (PU) und hochmolekularem – (HMWPE) und ultrahochmolekularem Polyethylen (UHMWPE) diskutiert. Zum Verständnis des Quellverhaltens dieser Polymerproben in niedermolekularen Lösungsmitteln werden neben den Messergebnissen Literaturdaten zu Grunde gelegt.
KW - Quellungsmessung
KW - Kohäsionsenergie
KW - Venetzungsdichte
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:526-opus4-3372
SN - 0949-8214
VL - 18
SP - 77
EP - 84
PB - News & Media
CY - Berlin
AN - OPUS4-32411
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mielke, Johannes
A1 - Hanke, F.
A1 - Peters, M.V.
A1 - Hecht, S.
A1 - Persson, M.
A1 - Grill, L.
T1 - Adatoms underneath single porphyrin molecules on Au(111)
N2 - The adsorption of porphyrin derivatives on a Au(111) surface was studied by scanning tunneling microscopy and spectroscopy at low temperatures in combination with density functional theory calculations. Different molecular appearances were found and could be assigned to the presence of single gold adatoms bonded by a coordination bond underneath the molecular monolayer, causing a characteristic change of the electronic structure of the molecules. Moreover, this interpretation could be confirmed by manipulation experiments of individual molecules on and off a single gold atom. This study provides a detailed understanding of the role of metal adatoms in surface–molecule bonding and anchoring and of the appearance of single molecules, and it should prove relevant for the imaging of related molecule–metal systems.
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324144
UR - http://pubs.acs.org/doi/pdf/10.1021/ja510528x
DO - https://doi.org/10.1021/ja510528x
SN - 0002-7863
SN - 1520-5126
VL - 137
IS - 5
SP - 1844
EP - 1849
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-32414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schick, D.
A1 - Herzog, M.
A1 - Bojahr, A.
A1 - Leitenberger, W.
A1 - Hertwig, Andreas
A1 - Shayduk, R.
A1 - Bargheer, M.
T1 - Ultrafast lattice response of photoexcited thin films studied by X-ray diffraction
N2 - Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates.
KW - Festkörperphysik
KW - Dünnschichttechnik
KW - Ellipsometrie
KW - Röntgenbeugung
KW - Optische Konstanten
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322471
DO - https://doi.org/10.1063/1.4901228
SN - 2329-7778
VL - 1
IS - 6
SP - 064501-1 - 064501-13
PB - AIP Publishing LLC
CY - Melville, NY
AN - OPUS4-32247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Busse, G.
A1 - Holtmann, N.
A1 - Myrach, Philipp
A1 - Rahammer, M.
A1 - Reischel, Mercedes
T1 - Standardisierung der Lockin-Thermografie: Vorstellung des TNS-Projektes und Auswahl der Probekörper
N2 - Ziel des Verbundprojektes zwischen der BAM und dem IKT der Universität Stuttgart ist die Festlegung einer einheitlichen Vorgehensweise für die Auswahl der Gerätekomponenten und für die Durchführung von Prüfungen mit der Lockin-Thermografie. Daraus soll ein Standard abgeleitet werden, der die Prüfung
unterschiedlicher Materialsysteme auf Fehlstellen mittels Lockin-Thermografie unter Berücksichtigung verschiedener Anregungsquellen ermöglicht. In diesem Beitrag wird die Entwicklung der Probekörper vorgestellt, die in diesem Projekt untersucht und später als Referenzprobekörper verwendet werden können.
T2 - Thermographie-Kolloquium 2013
CY - Leinfelden-Echterdingen, Germany
DA - 26.09.2013
KW - Thermografie
KW - Lock-in Thermografie
KW - Standardisierung
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-328258
SN - 978-3-940283-52-8
SP - Vortrag 7, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-32825
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Prager, Jens
A1 - Heide, M.
A1 - Homann, Patrick Tobias
A1 - Grzeszkowski, M.
A1 - Gaal, Mate
A1 - Dohse, Elmar
T1 - Einseitig-berührungslose Ultraschallprüfung von Klebeverbindungen
N2 - Durch den Einsatz von faserverstärkten Kunststoffen und Multi-Material-Konstruktionen zur Gewichtsreduzierung erlangen Klebeverbindungen immer stärkere Bedeutung. Die Prüfung dieser Fügeverbindungen stellt neue Anforderungen an die zerstörungsfreie Prüfung. Hinzu kommt, dass die Zugänglichkeit häufig eingeschränkt und die Verwendung flüssiger Koppelmittel aufgrund konstruktiver oder fertigungstechnischer Gegebenheiten ausgeschlossen ist. Unter Berücksichtigung dieser Beschränkungen wurde ein Prüfverfahren entwickelt, das eine luftgekoppelte Anregung geführter Ultraschallwellen mit einer laserbasierten Detektion kombiniert. Nachdem das Prüfverfahren zunächst mit einer einfachen Signalauswertung im Zeitbereich getestet wurde, konnte in nachfolgenden Untersuchungen die örtliche Auflösung durch die Implementierung von Filteralgorithmen im Frequenz-Wellenzahl-Bereich und zusätzlich durch direktionale Filter erhöht werden. Das resultierende bildgebende Prüfverfahren wurde an realitätsnahen Klebeproben mit künstlichen Fehlern getestet. Die Zuverlässigkeit und Ortsauflösung des Verfahrens wurde im Vergleich mit herkömmlichen Prüfverfahren validiert. Mithilfe des Verfahrens können Poren, Einschlüsse und Bereiche mit ungenügender Verklebung detektiert werden.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Strukturüberwachung
KW - Ultraschallprüfung
KW - Zerstörungsfreie Prüfung
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331944
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Mo.2.B.4, 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-33194
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guo, Y.
A1 - Lippitz, Andreas
A1 - Saftien, P.
A1 - Unger, Wolfgang
A1 - Kemnitz, E.
T1 - Tuning the surface properties of novel ternary iron(III) fluoride-based catalysts using the template effect of the matrix
N2 - Solgel prepared ternary FeF3–MgF2 materials have become promising heterogeneous catalysts due to their porosity and surface Lewis/Brønsted acidity (bi-acidity). Despite the good catalytic performance, nanoscopic characterisations of this type of material are still missing and the key factors controlling the surface properties have not yet been identified, impeding both a better understanding and further development of ternary fluoride catalysts. In this study, we characterised the interaction between the bi-acidic component (FeF3) and the matrix (MgF2) on the nano-scale. For the first time, the formation pathway of FeF3–MgF2 was profiled and the template effect of MgF2 during the synthesis process was discovered. Based on these new insights two novel materials, FeF3–CaF2 and FeF3–SrF2, were established, revealing that with decreasing the atomic numbers (from Sr to Mg), the ternary fluorides exhibited increasing surface acidity and surface area but decreasing pore size. These systematic changes gave rise to a panel of catalysts with tuneable surface and bulk properties either by changing the matrix alkaline earth metal fluoride or by adjusting their ratios to Fe or both. The template effect of the alkaline earth metal fluoride matrix was identified as the most probable key factor determining the surface properties and further influencing the catalytic performance in ternary fluoride based catalysts, and paves the way to targeted design of next-generation catalysts with tunable properties.
KW - Catalysis
KW - Surface analysis
KW - XPS
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-327410
DO - https://doi.org/10.1039/c4dt03229b
SN - 1477-9226
SN - 1477-9234
SN - 1364-5447
VL - 44
IS - 11
SP - 5076
EP - 5085
PB - RSC
CY - Cambridge
AN - OPUS4-32741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Dohse, Elmar
A1 - Bartusch, Jürgen
A1 - Köppe, Enrico
A1 - Kreutzbruck, Marc
A1 - Hillger, W.
A1 - Amos, J. M.
T1 - Ultrasonic testing of adhesively bonded joints using air-coupled cellular polypropylene transducers
N2 - In air-coupled ultrasonic testing, the impedance mismatch between the transducer and the air is commonly being solved by adding matching layers to composite transducers. To avoid the difficult technological procedure regarding matching layers, some new piezoelectric materials have been proposed. Most promising are ferroelectrets, which are charged cellular polymers, having ferroelectric and consequently piezoelectric properties. In particular, the extreme softness of cellular polypropylene (cPP) leads to a high piezoelectric constant and to a good impedance match with the air, making matching layers redundant. Its elasticity modulus below 1 MPa causes an additional effect not observed with common piezoelectric materials: that is the electrostrictive effect, here defined as the thickness change due to the attractive force between the transducer electrodes. This effect exceeds the piezoelectric effect at excitation voltages over 1 kV. The extreme softness of cPP leads also to high flexibility, enabling easy focusing by bending the transducer.
We have developed air-coupled ultrasonic transducers based on cPP. This includes the electrical matching networks for the transmitter and for the receiver. The transmitter is excited with voltages up to 2.5 kV, so that the electrostrictive effect dominates, leading to sound pressure around 145dB at the transducer surface. These transducers have been applied for testing carbon-fiber-reinforced polymer plates, adhesive joints and other composite structures. Here we report about ultrasonic transmission of two types of adhesive joints. The first one is multi-layer aluminium components with some artificial disbonds, which are common in aerospace industry, and the second one is an aluminium-steel joint with polyurethane adhesive, which is used in automotive industry.
T2 - ECNDT 2014 - 11th European conference on non-destructive testing
CY - Prague, Czech Republic
DA - 06.10.2014
KW - Air-coupled
KW - Ultrasonic testing
KW - Ferroelectret
KW - Cellular polypropylene
KW - Transducer
KW - Adhesive joint
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317204
SN - 978-80-214-5018-9
SP - 1
EP - 8
PB - Brno University of Technology
AN - OPUS4-31720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Köppe, Enrico
A1 - Augustin, D.
A1 - Bartholmai, Matthias
A1 - Daum, Werner
T1 - Air-based multi-hop sensor network for the localization of persons
N2 - In this work an air-based sensor network for the localization of persons at extensive areas is presented. The developed network consists of a localization device which the person is wearing (BodyGuard-System), a mobile relay station in the air, and a base station. All three parts communicate with the same radio chip. The BodyGuard-System is an inertial navigation system which was developed for localization in difficult environments with high accuracy and low measurement uncertainty. To increase the range of the system, a multi-hop network was built up. The measured data of the BodyGuard-System and the mobile relay station is visualized on a PC in the base station. This multi-hop network is necessary for example for fire department missions.
T2 - EuroSensors 2014, 28th European Conference on Solid-State Transducers
CY - Brescia, Italy
DA - 07.09.2014
KW - WSN
KW - Mesh routing
KW - Air-based
KW - Multi-hop
KW - Localization
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324294
DO - https://doi.org/10.1016/j.proeng.2014.11.540
SN - 1877-7058
VL - 87
SP - 528
EP - 531
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-32429
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ewert, Uwe
A1 - Zscherpel, Uwe
T1 - Minimum requirements for digital radiography equipment and measurement procedures by different industries and standard organizations
N2 - The digital photography has almost completely substituted the film photography. The film replacement is also fast progressing in medical X-ray radiography. This process is slower in NDT and especially in Europe. Reasons for the hesitating change to digital radiography (RT-D) in NDT are the necessary time for adoption of standards and the conservative request for film RT by auditors and NDT managers for applications in large plants and at construction areas. The fast serial inspection for small castings is already almost completely dominated by RT-D due to the cost effective short exposure and interpretation times. Standards were developed in parallel at CEN, ISO, ASTM and ASME. Unfortunately, the standard practices are different and the requirements on image quality and useable hardware are different too. The first standard series on Computed Radiography were developed and published by CEN and ASTM in 2005. Harmonized classification and qualification standards are available but the published practices are different. ASTM has developed the first standards for application of Digital Detector Arrays (DDA) in 2010. The first digital RT ISO standard practice is ISO 17636-2 (2013), which describes the practice for application of DDAs and Imaging Plates for weld inspection. At the first time this standard provides requirements for the selection of suitable hardware. Minimum image quality requirements are specified in analogy to film radiography and 3 Compensation Principles are defined to enable the application of a wider range of digital detectors. A comparison of the different international digital RT standards is given and first experiences with ISO 17636-2 are discussed. New standards on RT wall thickness and corrosion measurements (EN 16407, film and digital) have been developed recently.
T2 - ECNDT 2014 - 11th European conference on non-destructive testing
CY - Prague, Czech Republic
DA - 06.10.2014
KW - NDT
KW - X-Ray
KW - Digital detectors
KW - Standards
KW - Radiographic procedures
KW - Unsharpness
KW - Basic spatial resolution
KW - Requirements
KW - Digital industrial radiology
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323081
UR - https://www.ndt.net/?id=16708
SN - 1435-4934
VL - 19
IS - 12
SP - 1
EP - 18
PB - NDT.net
CY - Kirchwald
AN - OPUS4-32308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ballier, G.
A1 - Mayer, K.
A1 - Krause, Martin
T1 - Ultraschallabbildung zur zerstörungsfreien Strukturbestimmung von Betonbauteilen mit Hilfe der "One-Way"-Wellengleichung
N2 - Die ZfP versucht mit Hilfe von Messdaten, die sie aus z. B. einer Impuls-Echo-Messung gewinnt, Rückschlüsse auf die innere Struktur eines Objektes zu ziehen. Bei Betonbauteilen sollen im Besonderen Verpressfehler, die dann zur Korrosion und damit zur einer Beeinträchtigung der Standsicherheit und Dauerhaftigkeit des Konstruktion (z. B. einer Spannbetonbrücke) führen können, schnell und mit einer hohen Sicherheit aus den Messdaten lokalisiert werden. Das konventionellen SAFT oder FT-SAFT-Verfahren liefern in Verbindung mit einer Phasenauswertung einen schnellen und sicheren Hinweis darauf, dass ein Lufteinschluss/Defekt vorliegt. Darüber hinaus können jedoch Rückausbreitungs-Verfahren, wenn ein gutes Geschwindigkeitsprofil vorliegt, eine wesentlich bessere Lokalisierung des Defekts bieten als SAFT-Verfahren, jedoch mit dem Nachteil, dass sie sehr zeit- und rechenintensiv sind, vor allem im Dreidimensionalen. Als Mittelweg kann hierzu die "One-Way"-Methode dienen. Diese Methode verwendet Pseudo-Differential-Operatoren und ist sehr robust auch bei relativ groben Geschwindigkeitsprofilen. Sie wird an Beispielen aus der Bauwerkdiagnose mit den konventionellen Verfahren verglichen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Ultraschallecho-Verfahren
KW - Betonbauteile
KW - Modellierung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-328714
SN - 978-3-940283-33-7
SP - Poster 66, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-32871
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hothan, Sascha
A1 - Häßler, Dustin
T1 - Über die Entwicklung von Anwendungsregeln für reaktive Brandschutzsysteme auf Stahlzuggliedern
N2 - Der vorliegende Beitrag stellt den Entwicklungsstand von Anwendungsregeln für reaktive Brandschutzsysteme auf Stahlzuggliedern zusammenfassend dar. Dabei wird insbesondere auf die jüngsten Veränderungen in den normativen Grundlagen und bauaufsichtlichen Regelungen eingegangen und im Hinblick auf Sicherheitsaspekte bewertet.
Die Verringerung der Teilsicherheit für den Bauteilwiderstand nicht stabilitätsgefährdeter Bauteile im Regelwerk für die Kaltbemessung von Stahltragwerken ist hier als besonders kritisch anzusehen, da hierdurch ein systematisches Sicherheitsdefizit für den Brandfall verursacht wird.
Weiterhin werden neuste Forschungsergebnisse bei der Entwicklung von Bewertungsregeln von reaktiven Brandschutzsystemen auf Vollkreisprofilen unter Zugbeanspruchung vorgestellt und diskutiert. Die Untersuchungen behandeln die Fragestellung, inwieweit Prüfungen mit Zugbeanspruchungen an Kreisvollprofilen erforderlich sein werden.
KW - Stahlkonstruktion
KW - Brandschutz
KW - Reaktive Brandschutzsysteme
KW - Zugglieder
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-307949
DO - https://doi.org/10.2314/GBV:77999762X
SP - 141
EP - 148
PB - Institut für Stahlbau / Leibniz Universität Hannover
CY - Hannover
AN - OPUS4-30794
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, Daniel
A1 - Müller, Christina
A1 - Pitkänen, J.
T1 - Evaluation of radiographic testing performance with an advanced POD approach
N2 - POD is the most often used approach for the evaluation of the reliability of non-destructive testing methods in critical areas. But especially for those cases the requirements for a sufficient amount of data, adequate type of defects and the statistical requirements are high. The claim for checking these requirements is not new, but never the less often ignored. Especially the large amount of data for critical real defects seems too often to be not really solvable. In this presentation we show an approach to use real defect data with knowledge from former testing results with the same equipment, in a useful adequate way. Furthermore we introduce a method to evaluate the real defect description parameters for the radiographic testing. This approach was used for a joint project with the company POSIVA, which is building a final depository for spent nuclear fuel in Finland. Radiographic testing is one of the NDT-methods they use to test the electron beam weld of the copper canister. The copper canister will be used in the deposit as a corrosion barrier within the deposit concept. Through the high sophisticated manufacturing methods of the canister there are almost no material defects, which could be used for reliability evaluation. In this context the idea of Bayesian Updating of the POD with real defect data with former results from artificial defect data was born to get a useful evaluation.
T2 - 5th European-American workshop on reliability of NDE
CY - Berlin, Germany
DA - 07.10.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312641
SN - 978-3-940283-53-5
IS - DGZfP-BB 144
SP - Lecture 4, 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31264
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mozetic, M.
A1 - Ostrikov, K.
A1 - Ruzic, D.N.
A1 - Curreli, D.
A1 - Cvelbar, U.
A1 - Vesel, A.
A1 - Primc, G.
A1 - Leisch, M.
A1 - Jousten, K.
A1 - Malyshev, O.B.
A1 - Hendricks, J.H.
A1 - Kövér, L.
A1 - Tagliaferro, A.
A1 - Conde, O.
A1 - Silvestre, A.J.
A1 - Giapintzakis, J.
A1 - Buljan, M.
A1 - Radic, N.
A1 - Drazic, G.
A1 - Bernstorff, S.
A1 - Biedermann, H.
A1 - Kylián, O.
A1 - Hanus, J.
A1 - Milosevic, S.
A1 - Galtayries, A.
A1 - Dietrich, Paul
A1 - Unger, Wolfgang
A1 - Lehocky, M.
A1 - Sedlarik, V.
A1 - Stana-Kleinschek, K.
A1 - Drmota-Petric, A.
A1 - Pireaux, J.J.
A1 - Rogers, J.W.
A1 - Anderle, M.
T1 - Recent advances in vacuum sciences and applications
N2 - Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. The innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in the construction of huge ultra-high vacuum devices worldwide are reviewed. Recent advances in surface science and thin films include new phenomena observed in electron transport near solid surfaces as well as novel results on the properties of carbon nanomaterials. Precise techniques for surface and thin-film characterization have been applied in the conservation technology of cultural heritage objects and recent advances in the characterization of biointerfaces are presented. The combination of various vacuum and atmospheric-pressure techniques enables an insight into the complex phenomena of protein and other biomolecule conformations on solid surfaces. Studying these phenomena at solid–liquid interfaces is regarded as the main issue in the development of alternative techniques for drug delivery, tissue engineering and thus the development of innovative techniques for curing cancer and cardiovascular diseases. A review on recent advances in plasma medicine is presented as well as novel hypotheses on cell apoptosis upon treatment with gaseous plasma. Finally, recent advances in plasma nanoscience are illustrated with several examples and a roadmap for future activities is presented.
KW - Vacuum
KW - Surface
KW - Plasma
KW - Interface
KW - Nanoscience
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304884
DO - https://doi.org/10.1088/0022-3727/47/15/153001
SN - 0022-3727
SN - 1361-6463
VL - 47
IS - 15
SP - 153001-1
EP - 153001-23
PB - IOP Publ.
CY - Bristol
AN - OPUS4-30488
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schott, M.
A1 - Szczerba, Wojciech
A1 - Kurth, D.G.
T1 - Detailed study of layer-by-layer self-assembled and dip-coated electrochromic thin films based on metallo-supramolecular polymers
N2 - Electrochromic thin films of metallo-supramolecular polyelectrolytes based on Fe(OAc)2 and 1,4-bis(2,2':6',2''-terpyridin-4'-yl)benzene are readily prepared by layer-by-layer (LbL) deposition or dip-coating on transparent conducting electrode surfaces. By applying a potential, we can switch the color of the films from blue to colorless. Because of the strong absorption and the fast switching speed, the color change can be observed with the eye. The devices show reversible switching and cycle stability.
KW - Layer-by-layer self assembly
KW - Dip coating
KW - Thin films
KW - Metallo-supramolecular polyelectrolytes
KW - Electrochromism
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317347
DO - https://doi.org/10.1021/la501590a
SN - 0743-7463
SN - 1520-5827
VL - 30
IS - 35
SP - 10721
EP - 10727
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-31734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Sascha
A1 - Muanenda, Y. S.
A1 - Münzenberger, Sven
A1 - Krebber, Katerina
T1 - Relative change measurement of physical quantities using dual-wavelength coherent OTDR
N2 - We propose the use of alternating pulse wavelengths in a direct-detection coherent optical time domain reflectometry (C-OTDR) setup not only to measure strain and temperature changes but also to determine the correct algebraic sign of the change. The sign information is essential for the intended use in distributed mode shape analysis of civil engineering structures. Correlating relative backscatter signal shifts in the temporal/signal domain allows for measuring with correct magnitude and sign. This novel approach is simulated, experimentally implemented and demonstrated for temperature change measurement at a spatial resolution of 1 m.
KW - Fiber optics sensors
KW - Backscattering
KW - Rayleigh
KW - C-OTDR
KW - Distributed sensing
KW - Temperature measurement
KW - Strain measurement
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389449
DO - https://doi.org/10.1364/OE.25.000720
SN - 1094-4087
VL - 25
IS - 2
SP - 720
EP - 729
PB - Optical Society of America
CY - Washington, DC, USA
AN - OPUS4-38944
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Unger, Wolfgang
T1 - Non-destructive surface measurements
N2 - Materials and chemical producers require detailed knowledge of surface chemistry for research into new products. One way to understand a surface without damaging it is to bombard it with an electron beam, causing its atoms to emit characteristic X-rays enabling identification. The measurement of these must be precise as many elements emissions are close in energy – traceable reference materials will ensure instruments using this technique are stable and accurate.
KW - Metrology
KW - EDS
KW - EDX
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388647
UR - http://www.euramet.org/metrology-for-societys-challenges/metrology-for-industry/impact-case-studies-emrp-industry-theme/
SP - 1
EP - 2
CY - Teddington
AN - OPUS4-38864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unnikrishnakurup, Sreedhar
A1 - Kidangan, R. T.
A1 - P. Vengara, N.
A1 - Balasubramaniam, Krishnan
A1 - Rajagopal, P.
A1 - Phani Prabhakar, K. V.
A1 - Padmanabham, G.
T1 - Application of infrared thermography technique for the monitoring of cold metal transfer (CMT) joining of aluminium to galvanized steel
N2 - In this study, the feasibility of using non-contact Infrared thermography as a potential tool to monitor the CMT welding process is explored. The presence of internal defects such as porosity, lack of filler material deposition and formation of improper weld bead produce perturbations in the surface temperature which can be identified using an Infrared thermography technique. We present recent results obtained from online monitoring of the the dissimilar joining using CMT weld brazing of Aluminum and Steel using a transmission mode measurement approach. The effect of loss of zinc coating on the weldability of the cold metal transfer joining of aluminum to galvanised steel was investigated. A correlation between measured online thermal indications with the weld anomalies is successfully attempted and the results are compared with the conventional post-weld NDT inspection methods.
T2 - 19th World Conference on Non-Destructive Testing (WCNDT 2016)
CY - Munich, Germany
DA - 13 June 2016
KW - Infrared thermography
KW - CMT welding
KW - Weld defects
KW - Online monitoring
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389155
UR - http://ndt.net/?id=19475
SN - 1435-4934
VL - 21
IS - 7
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-38915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dieck, S.
A1 - Rosemann, Paul
A1 - Kromm, Arne
A1 - Halle, T.
T1 - Reversed austenite for enhancing ductility of martensitic stainless steel
N2 - The novel heat treatment concept, “quenching and partitioning” (Q&P) has been developed for high strength steels with enhanced formability. This heat treatment involves quenching of austenite to a temperature between martensite start and finish, to receive a several amount of retained austenite. During the subsequent annealing treatment, the so called partitioning, the retained austenite is stabilized due to carbon diffusion, which results in enhanced formability and strength regarding strain induced austenite to martensite transformation. In this study a Q&P heat treatment was applied to a Fe-0.45C-0.65Mn-0.34Si-13.95Cr stainless martensite. Thereby the initial quench end temperature and the partitioning time were varied to characterize their influence on microstructural evolution. The microstructural changes were analysed by dilatometer measurements, X-ray diffraction and scanning electron microscopy, including electron backscatter diffraction. Compression testing was made to examine the mechanical behaviour. It was found that an increasing partitioning time up to 30 min leads to an enhanced formability without loss in strength due to a higher amount of stabilized retained and reversed austenite as well as precipitation hardening.
T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
DA - 16.03.2017
KW - Quenching and partitioning
KW - Martensitic stainless steels
KW - Heat treatment
KW - Transformation induced plasticity
KW - High ductility
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395328
DO - https://doi.org/10.1088/1757-899X/181/1/012034
SN - 1757-899X
SN - 1757-8981
VL - 181
IS - Conference 1
SP - Article UNSP 012034, 1
EP - 8
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-39532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Jan P.
A1 - Götschel, S.
A1 - Weiser, M.
A1 - Maierhofer, Christiane
T1 - Thermografie mit optimierter Anregung für die quantitative Untersuchung von Delaminationen in kohlenstofffaserverstärkten Kunststoffen
N2 - Da kohlenstofffaserverstärkte Kunststoffe (CFK) in anspruchsvollen sicherheitsrelevanten Einsatzgebieten wie im Automobilbau und in der Luftfahrt eingesetzt werden, besteht ein zunehmender Bedarf an zerstörungsfreien Prüfmethoden. Ziel ist die Gewährleistung der Sicherheit und Zuverlässigkeit der eingesetzten Bauteile. Aktive Thermografieverfahren ermöglichen die effiziente Prüfung großer Flächen mit hoher Auflösung in wenigen Arbeitsschritten. Ein wichtiges Teilgebiet der Prüfungen ist die Ortung und Charakterisierung von Delaminationen, die sowohl bereits in der Fertigung als auch während der Nutzung eines Bauteils auftreten können, und dessen strukturelle Integrität schwächen.
In diesem Beitrag werden CFK-Strukturen mit künstlichen und natürlichen Delaminationen mit Hilfe unterschiedlich zeitlich modulierter Strahlungsquellen experimentell untersucht. Verwendet werden dabei Anregungen mit Blitzlampen und mit frequenzmodulierten Halogenlampen. Mittels Filterfunktionen im Zeit- und Frequenzbereich wird das Kontrast-zu-Rausch-Verhältnis (CNR) der detektierten Fehlstellen optimiert. Verglichen werden anschließend die Nachweisempfindlichkeit, das CNR und die Ortsauflösung der zu charakterisierenden Delaminationen für die unterschiedlichen Anregungs- und Auswertungstechniken. Ergänzt werden die Experimente durch numerische Simulationen des dreidimensionalen Wärmetransportes.
T2 - DGZfP Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - CFK
KW - Contrast Noise Ratio
KW - Lock-in Thermografie
KW - Gepulste Thermografie
KW - Kurzzeit-Fouriertransformation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404276
SN - 978-3-940283-85-6
VL - DGZfP BB 162
SP - Mi.1.A.4, 1
EP - 11
AN - OPUS4-40427
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stajanca, Pavol
A1 - Krebber, Katerina
ED - Webb, D. J.
ED - Scully, P.
ED - Sugden, K.
T1 - Radiation induced attenuation in perfluorinated polymer optical fibres for dosimetry applications
N2 - Real-time measurement of radiation-induced attenuation (RIA) in a commercial perfluorinated polymer optical fibre (PF-POF) is performed with regard to on-line Radiation monitoring purposes. Spectral character and dose dependence of fibre’s RIA is measured in 450-900 nm spectral region. Fibre exhibited high radiation sensitivity in the visible region with strong increase towards the UV wavelengths. Good linearity and high sensitivity reaching up to 130 dBm-1/kGy was demonstrated in the VIS region for a low-dose range. This of-the-shelf PF-POF could be therefore interesting for on-line remote dosimetry applications.
T2 - POF 2016: 25th International Conference on Plastic Optical Fibres
CY - Birmingham, UK
DA - 13.09.2016
KW - Perfluorinated polymer optical fibers
KW - Gamma radiation monitoring
KW - Radiation induced attenuation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403221
SN - 978-1-85449-408-5
SP - 167
EP - 170
CY - Birmingham
AN - OPUS4-40322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlke, Dirk
A1 - Meinig, Silvia
A1 - Kaszemeikat, T.
T1 - Hochauflösende Reinheitsgradbestimmung - Fertigung von Referenzfehlern
N2 - Regelwerke zur zerstörungsfreien Bestimmung des Reinheitsgrades wie das SEP 1927 und die ASTM E588 erreichen ihre Vergleichbarkeit unter Anwendung von - vergleichsweise einfachen - Referenzfehlern. Hinsichtlich Realisierbarkeit wird somit der Kompromiss zwischen Herstellung des Referenzfehlers und der erreichbaren Nachweisgrenze gefunden. Zur Weiterentwicklung über die Grenzen der SEP1927 hinaus, wurde der Versuch unternommen Fehler kleiner 500 μm herzustellen - welche aufgrund der geringen geometrischen Ausdehnung fertigungsbedingt schwierig zu realisieren sind. Bei den vergleichenden Untersuchungen kristallisierten sich zwei Fertigungsverfahren, Funkenerosion (EDM: electrical discharge maching) und die Fertigung der Bohrungen unter Verwendung eines Hochleistungslasers, als vielversprechend heraus. Zunächst wurden die Fehler mit beiden Verfahren in unterschiedlichen Größen (100, 250 und 100 μm) und Tiefen (1, 1,5 und 2 mm) unter Anwendung von computertomographischen Verfahren der Röntgenprüfung, die Geometrie der eingebrachten Fehlstellen und anschließend durch hochauflösende Tauchtechnikmessungen das Reflektionsverhalten charakterisiert.
T2 - DGZfP Jahrestagung
CY - Koblenz, Germany
DA - 22.05.2017
KW - Materialcharakterisierung
KW - Reinheitsgradbestimmung
KW - Ultraschalltauchtechnik
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403505
SN - 978-3-940283-85-6
SP - P20, 1
EP - 2
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-40350
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Munzke, Dorit
A1 - Pohl, Rainer
T1 - Wirbelstromprüfung an Composite-Druckgefäßen
N2 - Composite-Druckgefäße für den Gefahrguttransport sowie für Wasserstoff- und Erdgasfahrzeuge bestehen aus einem lasttragenden Composite und einer gasdichten, metallischen oder polymeren Barriereschicht (Liner). Zur Untersuchung des Alterungsverhaltens solcher Composite-Druckgefäße wird in der BAM das interdisziplinäre Themenfeldprojekt COD-AGE durchgeführt. Ziel des Projektes ist die Entwicklung von Methoden und Modellen zur Beschreibung und Bestimmung des Alterungsverhaltens von Carbonfaser-Compositen (CFK) am Beispiel von Druckgefäßen, um eine bessere Vorhersage der Alterung und der sicheren Gebrauchsdauer zu ermöglichen.
Ein Schwerpunkt in diesem Projekt ist die Bereitstellung geeigneter ZfP-Methoden. Dabei geht es sowohl um versuchsbegleitende Prüfungen, als auch um die mögliche Entwicklung von Prüfeinrichtungen für den späteren praktischen Gebrauch. In diesem Vortrag werden Prüfsysteme und Prüfergebnisse der „konventionellen“ Wirbelstromprüfung vorgestellt. In einem ersten Schritt wurden Versuche an bereits geschädigten Druckgefäßen durchgeführt. Dabei wurden Druckgefäße mit den Materialpaarungen Stahl-CFK, Aluminium-CFK und Kunststoff-CFK untersucht. Die Dicken der CFK-Schichten reichten hierbei von ca. 4 mm bis ca. 8 mm. Anfangs wurden die Gefäße mit verschiedenen Sensoren von außen geprüft. Es konnten sowohl Beschädigungen des metallischen Liners, als auch Strukturen des CFK-Geflechts nachgewiesen werden. In einem zweiten Schritt wurden die Gefäße von innen geprüft. Hierbei bestand die besondere Herausforderung in der Prüfung eines Zylinders von 150 mm Durchmesser durch einen Zugang von nur 15 mm Durchmesser.
Mit den bei diesen Vorversuchen optimierten Prüfsystemen wurden dann begleitende Prüfungen bei Alterungsversuchen durchgeführt. In den Alterungsversuchen wurden Druckbehälter mit einem ca. 4 mm dicken Aluminiumliner und ca. 3,5 mm dicker CFK-Ummantelung untersucht. Typisches Einsatzgebiet solcher Flaschen sind Atemschutzgeräte bei der Feuerwehr. Die verschiedenen Prüfsysteme und die mit ihnen erzielten Ergebnisse werden vorgestellt.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Composite-Druckgefäß
KW - Wirbelstromprüfung
KW - CFK
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403577
SN - 978-3-940283-85-6
VL - 162
SP - 1
EP - 9
PB - DGZfP e.V.
AN - OPUS4-40357
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Unger, Wolfgang
T1 - IND15 JRP SurfChem: Traceable quantitative surface chemical analysis for industrial applications
N2 - The SurfChem project has made a significant contribution to traceable quantitative surface chemical analysis for industrial applications by delivering new certified reference materials and test samples for specific technical applications. Regular performance tests of instruments, metrological methodology for the detection of (bio)organic surface species, ambient and non-destructive surface chemical analysis for in-line process control and new in situ characterisation techniques of catalytically active surfaces have been achieved.
KW - Surface analysis
KW - Metrology
KW - Euramet EMRP
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388673
UR - http://www.euramet.org/research-innovation/search-research-projects/details/?eurametCtcp_project_show%5Bproject%5D=1115&eurametCtcp_project%5Bback%5D=893&cHash=5fd23fc7f759db18176584b5d8a5fe89
SP - 1
EP - 39
CY - Teddington
AN - OPUS4-38867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oberleitner, Lidia
A1 - Garbe, L.-A.
A1 - Dahmen-Levison, Ursula
A1 - Schneider, Rudolf
T1 - Improved strategies for selection and characterization of new monoclonal anticarbamazepine antibodies during the screening process using feces and fluorescence polarization immunoassay
N2 - Immunoassays are suitable tools for high-throughput screenings. The prerequisite for accurate determinations by these methods is the selection of an excellent antibody. The production and selection of monoclonal antibodies is usually a tedious process. In this study, new strategies for improving antibody production and characterization were applied. This includes the monitoring of the immunization progress in mice through antibodies extracted from feces, which allows a time-resolved and animal-friendly monitoring of the immune response. Additionally, fluorescence polarization immunoassay (FPIA) could be successfully applied for fast and easy examination of cell culture supernatants and the investigation of antibody/antigen interactions including kinetics and fluorescence properties. These methods simplify the selection of the optimal antibody. As a target analyte, carbamazepine was chosen. This is a widely used antiepileptic drug which also frequently occurs in the environment. The new antibody enables CBZ determination in the concentration range 0.66–110 µg L-1 within 10 min using a high-throughput microtiter plate-based FPIA, and between 1.4 and 79 µg L-1 within 5 min applying an automated cuvette-based FPIA instrument, and from 0.05–36 µg L-1 using ELISA. The measurements were performed at a non-equilibrium state which improved the sensitivity and selectivity of the assays. Due to low cross-reactivity especially towards the main CBZ metabolite and other pharmaceuticals (<1%), this antibody gives the opportunity for application in medical and environmental analyses.
KW - Antikörper
KW - Emerging Pollutants
KW - Schadstoffe
KW - Monoklonal
KW - Pharmazeutika
KW - Arzneistoffe
KW - Assay
KW - Pesticide parathion-methyl
KW - Waste-water
KW - Samples
KW - Pharmaceuticals
KW - Quantification
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-392473
DO - https://doi.org/10.1039/c6ay01968d
SN - 1759-9660
VL - 8
SP - 6883
EP - 6894
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-39247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Holm, Olaf
T1 - Exergetische Bewertung von Rohstoffen am Beispiel von Kupfer
T1 - Exergetic assessment of raw materials using the example of copper
N2 - Für die Herstellung von Kupfer aus Primär- und Sekundärressourcen wurde eine Exergieanalyse der Aufbereitungs- und Gewinnungsverfahren durchgeführt. Für die Stoffgemische Kupfererz, Kupferkonzentrat und Hausmüllverbrennungsasche wurden die Exergien tabellarisch berechnet. Die Exergieaufwände der technischen Prozesse zur Kupferherstellung wurden mit den thermodynamisch minimal notwendigen Aufwänden verglichen. Die Nutzung von Sekundärrohstoffen aus Abfällen ist über weite Bereiche vorteilhaft, insb. wenn das Kupfer bereits in der metallischen Form vorliegt.
KW - Exergie
KW - Hausmüllverbrennungsasche
KW - Hydrometallurgie
KW - Pyrometallurgie
KW - Kumulierter Exergieaufwand
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390496
UR - http://onlinelibrary.wiley.com/doi/10.1002/cite.201600089/epdf
DO - https://doi.org/10.1002/cite.201600089
SN - 1522-2640
SN - 0009-286X
VL - 89
IS - 1-2, SI
SP - 108
EP - 116
PB - Wiley VCH Verlag
CY - Weinheim
AN - OPUS4-39049
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hernández-Nava, E.
A1 - Smith, C.J.
A1 - Derguti, F.
A1 - Tammas-Williams, S.
A1 - Léonard, Fabien
A1 - Withers, P. J.
A1 - Todd, I.
A1 - Goodall, R.
T1 - The effect of defects on the mechanical response of Ti-6Al-4V cubic lattice structures fabricated by electron beam melting
N2 - Electron Beam Melting (EBM) as a means of Additive Manufacturing (AM), is of interest for the fabrication of intricate geometries for cellular materials in areas where complex architectures are needed, e.g. biomedical implants. Most studies have focused on specific geometries and so the effect of the structure on mechanical performance is not well understood. Many kinds of micro- and macro-scale defects can arise in additively manufactured components, so assessment of their influence on properties is needed. In this work, lattices of Ti-6Al-4V having a cubic structure have been manufactured by EBM, and the effect of heat treatments above and below the β-transus temperature on microstructure and compression response have been investigated. The former modifies only slightly the α + β structure and mechanical performance whereas the latter leads to coarse alternating α and β lamellae packets and α at the prior grain boundaries with a 10% loss in yield strength. The variation in the compressive yield stress with strut diameter is in good accord with simple models based on compressive deformation rather than shearing or buckling. Internal pores for struts aligned with the build direction are found around the edges of the solid form, in regions which seem to be associated with the EB scan pattern. Struts normal to the build direction show more significant defects but their redundancy means that they do not compromise the compressive performance in the build direction. Using a particle size in the range 45–100 μm minimum weld-track sizes were experimentally and numerically identified to be 176 and 148 μm in depth respectively with a depth-to-width ratio of 0.55. This produced a beam pass of the order of 300 μm oversizing small features (struts of 0.4 and 0.6 mm nominal diameter) when a contour around the strut periphery was applied.
KW - Cellular solids
KW - Additive manufacturing
KW - Titanium alloy
KW - Mechanical properties
KW - X-ray computed tomography
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390686
DO - https://doi.org/10.1016/j.actamat.2016.02.029
SN - 1359-6454
VL - 108
SP - 279
EP - 292
PB - Elsevier Ltd.
CY - Amsterdam [u.a.]
AN - OPUS4-39068
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindzierski, V.
A1 - Raschke, Silvia
A1 - Knabe, Nicole
A1 - Siedler, F.
A1 - Scheffer, B.
A1 - Pflüger-Grau, K.
A1 - Pfeiffer, F.
A1 - Oesterhelt, D.
A1 - Marin-Sanguino, A.
A1 - Kunte, Hans-Jörg
T1 - Osmoregulation in the halophilic bacterium halomonas elongata: A case study for integrative systems biology
N2 - Halophilic bacteria use a variety of osmoregulatory methods, such as the accumulation of one or more compatible solutes. The wide diversity of compounds that can act as compatible solute complicates the task of understanding the different strategies that halophilic bacteria use to cope with salt. This is specially challenging when attempting to go beyond the pathway that produces a certain compatible solute towards an understanding of how the metabolic network as a whole addresses the problem. Metabolic reconstruction based on genomic data together with Flux Balance Analysis (FBA) is a promising tool to gain insight into this problem. However, as more of these reconstructions become available, it becomes clear that processes predicted by genome annotation may not reflect the processes that are active in vivo. As a case in point, E. coli is unable to grow aerobically on citrate in spite of having all the necessary genes to do it. It has also been shown that the realization of this genetic potential into an actual capability to metabolize citrate is an extremely unlikely event under normal evolutionary conditions. Moreover, many marine bacteria seem to have the same pathways to metabolize glucose but each species uses a different one. In this work, a metabolic network inferred from genomic annotation of the halophilic bacterium Halomonas elongata and proteomic profiling experiments are used as a starting point to motivate targeted experiments in order to find out some of the defining features of the osmoregulatory strategies of this bacterium. This new information is then used to refine the network in order to describe the actual capabilities of H. elongata, rather than its genetic potential.
KW - Halomonas elongata
KW - Systems biology
KW - Flux balance analysis
KW - Proteomic analysis
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391172
DO - https://doi.org/10.1371/journal.pone.0168818
SN - 1932-6203
VL - 12
IS - 1
SP - Article e0168818, 1
EP - 22
AN - OPUS4-39117
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kern, Simon
A1 - Gräßer, Patrick
A1 - Zientek, Nicolai
A1 - Maiwald, Michael
T1 - First steps towards field integration of benchtop NMR spectroscopy for online monitoring and process control
N2 - Online monitoring and process control requires fast and noninvasive analytical methods, which are able to monitor the concentration of reactants in multicomponent mixtures with parts-per-million resolution. Online NMR spectros-copy can meet these demands when flow probes are directly coupled to reactors, since this method features a high linearity between absolute signal area and sample concentration, which makes it an absolute analytical com-parison method being independent on the matrix. Due to improved magnet design and field shimming strategies portable and robust instruments have been introduced to the market by several manufacturers during the last few years. First studies with this technology showed promising results to monitor chemical reaction in the laboratory.
T2 - 11. Kolloquium Arbeitskreis Prozessanalytik
CY - Wien, Austria
DA - 30.11.2015
KW - Online NMR Spectroscopy
KW - Smart Sensors
KW - Prozess-Spektroskopie
KW - Process Analytical Technology
KW - Process control
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388411
SP - 43
EP - 44
AN - OPUS4-38841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Dietrich, P.
A1 - Thissen, A.
A1 - Kulak, N.
A1 - Kjaervik, Marit
A1 - Unger, Wolfgang
T1 - XPS surface chemical analysis of aqueous solutions with EnviroESCA
N2 - Water and aqueous reagents are essential in any biological process or system. But apart from a few special low vapor-pressure cases, liquids have not been accessible to any technique requiring UHV conditions. EnviroESCA opens up this exciting field of applications.
In this paper first results from water based samples are presented as a proof of concept to demonstrate the special capabilities of EnviroESCA analyzing liquid samples. The following solutions were investigated under near ambient pressure conditions: i.) water, ii.) brine, iii.) an oil in water dispersion, iv.) aqueous iron(II) sulfate heptahydrate, and v.) a suspension of nano silver particles in water.
KW - Surface Analysis
KW - Near Ambient Pressure XPS
KW - Aqueous Solutions
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394603
UR - http://www.enviro.specs.de/cms/upload/bilder/EnviroESCA/Applications/Liquids/Application-Note_EnviroESCA_Aqueous_Solutions.pdf
N1 - BAM Mitarbeiter Beitrag im Acknowledgement definiert.
IS - #000394
SP - 1
PB - SPECS
CY - Berlin
AN - OPUS4-39460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ho, Y.T.
A1 - Adriani, G
A1 - Beyer, Sebastian
A1 - Nhan, P.-T.
A1 - Kamm, R. D.
A1 - Kah, J.C.Y.
T1 - A facile method to probe the vascular permeability of nanoparticles in nanomedicine applications
N2 - The effectiveness of nanoparticles (NP) in nanomedicine depends on their ability to extravasate from vasculature towards the target tissue. This is determined by their permeability across the endothelial barrier. Unfortunately, a quantitative study of the diffusion permeability coefficients (Pd) of NPs is difficult with in vivo models. Here, we utilize a relevant model of vascular-tissue interface with tunable endothelial permeability in vitro based on microfluidics. Human umbilical vein endothelial cells (HUVECs) grown in microfluidic devices were treated with Angiopoietin 1 and cyclic adenosine monophosphate (cAMP) to vary the Pd of the HUVECs monolayer towards fluorescent polystyrene NPs (pNPs) of different sizes, which was determined from image analysis of their fluorescence intensity when diffusing across the monolayer. Using 70 kDa dextran as a probe, untreated HUVECs yielded a Pd that approximated tumor vasculature while HUVECs treated with 25 μg/mL cAMP had Pd that approximated healthy vasculature in vivo. As the size of pNPs increased, its Pd decreased in tumor vasculature, but remained largely unchanged in healthy vasculature, demonstrating a trend similar to tumor selectivity for smaller NPs. This microfluidic model of vascular-tissue interface can be used in any laboratory to perform quantitative assessment of the tumor selectivity of nanomedicine-based systems.
KW - Nanoparticle
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397053
DO - https://doi.org/10.1038/s41598-017-00750-3
SN - 2045-2322
VL - 7
IS - 1
SP - Article 707, 1
EP - 13
PB - Macmillan
AN - OPUS4-39705
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schürmann, Robin
A1 - Bald, Ilko
T1 - Real-time monitoring of plasmon induced dissociative electron transfer to the potential DNA radiosensitizer 8-bromoadenine
N2 - The excitation of localized surface plasmons in noble metal nanoparticles (NPs) results in different nanoscale effects such as electric field enhancement, the generation of hot electrons and a temperature increase close to the NP surface. These effects are typically exploited in diverse fields such as surface-enhanced Raman scattering (SERS), NP catalysis and photothermal therapy (PTT). Halogenated nucleobases are applied as radiosensitizers in conventional radiation cancer therapy due to their high reactivity towards secondary electrons. Here, we use SERS to study the transformation of 8-bromoadenine (8BrA) into adenine on the surface of Au and AgNPs upon irradiation with a low-power continuous wave laser at 532, 633 and 785 nm, respectively. The dissociation of 8BrA is ascribed to a hot-electron transfer reaction and the underlying kinetics are carefully explored. The reaction proceeds within seconds or even milliseconds. Similar dissociation reactions might also occur with other electrophilic molecules, which must be considered in the interpretation of respective SERS spectra. Furthermore, we suggest that hot-electron transfer induced dissociation of radiosensitizers such as 8BrA can be applied in the future in PTT to enhance the damage of tumor tissue upon irradiation.
KW - SERS
KW - Nanoparticles
KW - Hot electrons
KW - Bromoadenine
KW - Catalysis
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396469
DO - https://doi.org/10.1039/C6NR08695K
SN - 2040-3364
SN - 2040-3372
VL - 9
IS - 5
SP - 1951
EP - 1955
PB - RSC
AN - OPUS4-39646
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Holstein, R.
A1 - Müller, Christina
T1 - Analyzing the reliability of non-destructive tests using the modular modell - a practical approach
N2 - Non-destructive testing is an important tool to guarantee the safety of railway traffic.
The infrastructure with tracks, switches and sleepers is regularly tested, the
locomotives and wagons with their wheels, bogies and axles as well. Many years of experience and some events lead in Germany to a good practice in testing the railway components. Now, European authorities are drafting a system of common requirements and standards for the European Railway Market. The German practice combines an intensive training of the NDT-personnel including sufficient time for practical exercises with organizational measures of the companies, responsible for rolling stock and infrastructure. Through the example of UT-testing of railway axles it will be shown, how training and organizational measures influence the reliability of such testing.
T2 - 19th World Conference on Non-Destructive Testing
CY - München, Germany
DA - 13.06.2016
KW - NDT
KW - Reliability
KW - Modular model
KW - Railway
KW - Human factors
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375712
UR - http://www.ndt.net/article/wcndt2016/papers/mo1d4.pdf
SP - id 19519, 1
EP - 6
AN - OPUS4-37571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, D.
A1 - Müller, Christina
T1 - Evaluating RT systems with a new POD approach
N2 - The usefulness and purpose of evaluating nondestructive testing (NDT) systems and their capabilities has changed in the last decade. The conventional method of simply applying a familiar statistical algorithm to say whether the system is usable for the tasks is history.
Nowadays, multiple parameter methods which describe the probabilities of detection (POD) of different systems or real defects need new characteristics and a broader variety of statistical models to describe the true system behaviour. The appraisal of the NDT system involves diverse departments within a company (engineering, NDT-operators, and statisticians), but is, at the same time, more needed and requested than in the past. In this article, an approach is discussed in which professionals from different fields worked well together, accomplishing cost-intensive metallographic studies in correlation with well-understood physical behaviour of NDT-methods as well as deep-discussed mathematical methods to create a holistic evaluation of the technical reliability for a specific radiographic testing (RT) equipment. The first part of the publication will show the comparison between metallographic grinding and the RT indications. An essential innovation over past evaluation methods was the use of a multi-scale smoothing algorithm, which describes physical parameters, which were not used in evaluation like the POD in this way in the past.
In the second part the statistical requirements for the POD take the focus. It can often be hard to make significant statements; especially in the case where only a small amount of data is available. The combination of data and the use of knowledge from simulations are essential. One possible solution will be shown for the RT evaluation. The methodology is used for evaluating the digital RT system for the inspection of electron-beam welds, which was method considered to seal the Finnish copper canisters for the final deposit of spent nuclear fuel.
T2 - 19th World Conference on Non-Destructive Testing
CY - München, Germany
DA - 13.06.2016
KW - NDT
KW - Reliability
KW - POD
KW - RT
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375732
UR - http://www.ndt.net/article/wcndt2016/papers/we1d4.pdf
SP - id 19535, 1
EP - 8
AN - OPUS4-37573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Krankenhagen, Rainer
A1 - Röllig, Mathias
A1 - Riemer, Stefanie
A1 - Gower, M.
A1 - Baker, G.
A1 - Lodeiro, M.
A1 - Knazovicka, L.
A1 - Blahut, A.
A1 - Monte, C.
A1 - Adibekyan, A.
ED - Gutschwager, B.
T1 - Characterisation of artificial and natural defects in fibre reinforced plastics designed for energy applications using active thermography
N2 - Amongst various other NDT methods, within the EMRP-project
‘VITCEA’ active thermography is validated for testing of CFRP and
GFRP structures constructed for energy application. In this
contribution, the optical and thermal properties of CFRP and GFRP
reference defect artefact (RDA) and natural defects artefact (NDA)
test specimens are characterized. Different excitation techniques
and techniques for data analysis are compared for optimizing the
number of detected defects.
T2 - 19th World Conference on Non-destructive Testing (WCNDT)
CY - Munich, Germany
DA - 13.06.2016
KW - Active thermography
KW - CFRP
KW - GFRP
KW - Artificial and natural defects
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370207
UR - http://www.ndt.net/article/wcndt2016/papers/we2i4.pdf
SN - 978-3-940283-78-8
VL - BB 158
SP - Paper we2i4, 1
EP - 9
PB - DGZfP
CY - Berlin
AN - OPUS4-37020
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, Klas
A1 - Kern, Simon
A1 - Zientek, Nicolai
A1 - Guthausen, G.
A1 - Maiwald, Michael
T1 - Process control with compact NMR
N2 - Compact nuclear magnetic resonance (NMR) instruments make NMR spectroscopy and relaxometry accessible in industrial and harsh environments for reaction and process control. An increasing number of applications are reported. To build an interdisciplinary bridge between “process control” and “compact NMR”,we give a short overviewon current developments in the field of process Engineering such as modern process design, integrated processes, intensified processes along with requirements to process control, model based control, or soft sensing. Finally, robust field integration of NMR systems into processes environments, facing explosion protection or Integration into process control systems, are briefly discussed.
KW - Prozessanalytik
KW - Quantitative NMR-Spektroskopie
KW - Industrie 4.0
KW - Reaction monitoring
KW - Process control
KW - Online NMR spectroscopy
KW - Compact NMR
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373562
UR - http://www.sciencedirect.com/science/article/pii/S0165993616300073
DO - https://doi.org/10.1016/j.trac.2016.03.016
SN - 0165-9936
VL - 83
IS - Part A / SI
SP - 39
EP - 52
PB - Elsevier
AN - OPUS4-37356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kardjilov, N.
A1 - Hilger, A.
A1 - Manke, I.
A1 - Banhart, J.
A1 - Griesche, Axel
T1 - Imaging with Cold Neutrons at the CONRAD-2 Facility
N2 - CONRAD-2 is an imaging instrument using low-energy (cold) neutrons. The instrument is installed at the end of a curved neutron guide which avoids the direct line of sight towards the reactor core. This ensures a very low background of high-energy neutrons and. photons at the sample position. The cold neutron beam provides a wavelength range which is suitable for phase-and diffraction-contrast imaging such as grating interferometry and Bragg edge mapping. The instrument is well suited for high resolution imaging due to the high efficiency of the very thin scintillators that can be used for the detection of cold neutrons. An instrument upgrade was performed recently as a part of an upgrade program for the cold neutron instrumentation at HZB. The parameters of the instrument as well as some research highlights will be presented.
T2 - 10th World Conference on Neutron Radiography (WCNR)
CY - Grindelwald, SWITZERLAND
DA - 05.10.2014
KW - iron embrittlement
KW - neutron imaging
KW - neutron instrumentation
KW - cold neutrons
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373239
DO - https://doi.org/10.1016/j.phpro.2015.07.008
SN - 1875-3892
VL - 69
SP - 60
EP - 66
PB - Elsevier B.V.
CY - Amsterdam, NL
AN - OPUS4-37323
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Färber, C.
A1 - Titschack, J.
A1 - Schönberg, Chr. H. L.
A1 - Ehrig, Karsten
A1 - Boos, K.
A1 - Illerhaus, Bernhard
A1 - Asgaard, U.
A1 - Bromley, R. G.
A1 - Freiwald, A.
A1 - Wisshak, M.
ED - Bahn, M.
ED - Fennel, K.
ED - Kesselmeier, J.
ED - Naqvi, S. W. A.
T1 - Long-term macrobioerosion in the Mediterranean Sea assessed by micro-computed tomography
N2 - Biological erosion is a key process for the recycling of carbonate and the formation of calcareous sediments in the oceans. Experimental studies showed that bioerosion is subject to distinct temporal variability, but previous long-term studies were restricted to tropical waters. Here, we present results from a 14-year bioerosion experiment that was carried out along the rocky limestone coast of the island of Rhodes, Greece, in the Eastern Mediterranean Sea, in order to monitor the pace at which bioerosion affects carbonate substrate and the sequence of colonisation by bioeroding organisms. Internal macrobioerosion was visualised and quantified by micro-computed tomography and computer-algorithm-based segmentation procedures. Analysis of internal macrobioerosion traces revealed a dominance of bioeroding sponges producing eight types of characteristic Entobia cavity networks, which were matched to five different clionaid sponges by spicule identification in extracted tissue. The morphology of the entobians strongly varied depending on the species of the producing sponge, its ontogenetic stage, available space, and competition by other bioeroders. An early community developed during the first 5 years of exposure with initially very low macrobioerosion rates and was followed by an intermediate stage when sponges formed large and more diverse entobians and bioerosion rates in-creased. After 14 years, 30 % of the block volumes were occupied by boring sponges, yielding maximum bioerosion rates of 900 g m.
KW - Bioerosion
KW - Computed tomography
KW - Carbonate substrate
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372709
UR - http://www.biogeosciences.net/13/3461/2016/bg-13-3461-2016.pdf
DO - https://doi.org/10.5194/bg-13-3461-2016
VL - 13
IS - 11
SP - 3461
EP - 3474
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-37270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gravenkamp, Hauke
A1 - Bause, F.
A1 - Rautenberg, J.
A1 - Henning, B.
ED - Declercq, N. F.
T1 - Model Based Sensitivity Analysis in the Determination of Viscoelastic Material Properties Using Transmission Measurements through Circular Waveguides
N2 - Several ultrasonic approaches for material determination are formulated in terms of an (nonlinear) inverse problem, e.g. immersion technique (Castaings et al. (2000)) or plate-waveguide techniques (Marzani et al. (2012)). In this contribution we focus on cylindrical waveguides for ultrasonic material determination and especially on the sensitivity of recorded transmission signals to the material properties. We utilize composite scaled sensitivities to determine the information content that can be achieved by the setup to certain parameters and discuss the limitations of the approach.
T2 - ICU International Congress on Ultrasonics 2015
CY - Georgia Tech Lorraine, Metz, France
DA - 10.05.2015
KW - Ultrasonic material determination
KW - Sensitivity
KW - Inverse problem
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372551
DO - https://doi.org/10.1016/j.phpro.2015.08.127
SN - 1875-3892
VL - 70
SP - 204
EP - 207
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-37255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiggenhauser, Herbert
A1 - Samokrutov, A.A.
A1 - Mayer, K.
A1 - Krause, Martin
A1 - Alekhin, S. G.
A1 - Elkin, V.
T1 - LAUS - Large aperture ultrasonic system - for testing thick concrete structures
N2 - A Large Aperture UltraSonic (LAUS) system has been designed and built for testing thick concrete structures. The scalable system consists of twelve ultrasonic units, each hosting 32 individual shear wave transducers with mechanical dry point contact (DPC) to the concrete surface. The twelve units are attached to the concrete surface using a vacuum case which holds them in place during operation. Each LAUS unit can be placed individually depending on the surface condition and optimal ultrasonic condition, e.g. rebar position. Air pressure is supplied to each unit through an air hose. The following extended abstract is a short version of an article to be published in the special edition of ASCE JIS that will describe the outline of the system, the principle of functioning, the data processing and adapted reconstruction calculation based on SAFT as well as the system performance during first applications.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Ultrasonic imaging
KW - Linear array
KW - Reconstruction calculation (SAFT)
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345383
UR - http://www.ndt.net/?id=18313
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Röllig, Mathias
A1 - Ehrig, Karsten
A1 - Meinel, Dietmar
T1 - Validierung der aktiven Thermografie mittels CT zur Charakterisierung von Inhomogenitäten und Fehlstellen in CFK
N2 - Aktive Thermografieverfahren werden immer häufiger zur zerstörungsfreien Prüfung von Faserverbundwerkstoffen eingesetzt, da diese völlig berührungslos arbeiten und sowohl zur Prüfung großflächiger Strukturen als auch von großen Stückzahlen kleinerer Komponenten in der Fertigung eingesetzt werden können. Dieser Beitrag beschäftigt sich mit Untersuchungen an typischen Defekten und Inhomogenitäten, die bereits während der Fertigung von CFK Bauteilen entstehen oder unbeabsichtigt mit eingebaut werden. Systematische Untersuchungen wurden mit Blitzthermografie in Reflexions- und Transmissionskonfiguration und mit Computertomographie (CT) durchgeführt. Die CT wurde dabei als Referenzverfahren genutzt, da dieses Verfahren auch kleinere Defekte mit relativ hoher Ortsauflösung und unabhängig von der Tiefe darstellen kann.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Aktive Thermografie
KW - Computer Tomographie
KW - Aluminium Druckguss
KW - Poren
KW - Validierung
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345251
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Mi.3.C.1, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-34525
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Simultaneous measurements of the vehicle, track, and soil vibrations at a surface, bridge, and tunnel railway line
N2 - A complex measuring campaign has been performed including the simultaneous measurement of vehicle, track, and soil vibrations during train runs at 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. A ballast track on the soil surface and on a concrete bridge have been investigated as well as a slab track in a tunnel. The evaluation and comparison of all these data shows a generally good agreement for all components if the strong low- and high-frequency cut-off characteristics of the layered and damped soil are incorporated. There is a strong causal correlation between the vehicle and the soil by the dynamic excitation forces and a weak relation between the track and the soil by the axle-sequence spectrum of the train. However, the similarity between the axle-impulse spectrum observed at the track and the spectra of the ground vibration lead to the special excitation component of “scattered axle impulses” which is pre-dominant at the far-field points of the soil.
KW - Railway
KW - Ground vibration
KW - Vehicle-track interaction
KW - Track-soil interaction
KW - Measurements
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410224
DO - https://doi.org/10.1155/2017/1959286
VL - 2017
IS - ID 1959286
SP - 1
EP - 18
PB - Hindawi
CY - Indien
AN - OPUS4-41022
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dutto, Paola
A1 - Stickle, M. M.
A1 - Pastor, M.
A1 - Manzanal, D.
A1 - Yague, A.
A1 - Tayyebi, S.
A1 - Lin, C.
A1 - Elizalde, M. D.
ED - Cervera, Miguel
T1 - Modelling of fluidised geomaterials: the case of the Aberfan and the Gypsum tailings impoundment flowslides
N2 - The choice of a pure cohesive or a pure frictional viscoplastic model to represent the rheological behaviour of a flowslide is of paramount importance in order to obtain accurate results for real cases. The principal Goal of the present work is to clarify the influence of the type of viscous model—pure cohesive versus pure frictional—with the numerical reproduction of two different real flowslides that occurred in 1966: the Aberfan flowslide and the Gypsum tailings impoundment flowslide. In the present work, a depth-integrated model based on the v-pw Biot–Zienkiewicz formulation, enhanced with a diffusion-like equation to account for the pore pressure Evolution within the soil mass, is applied to both 1966 cases. For the Aberfan flowslide, a frictional viscous model based on Perzyna viscoplasticity is considered, while a pure cohesive viscous model (Bingham model) is considered for the case of the Gypsum flowslide. The numerical approach followed is the SPH method, which has been enriched by adding a 1D finite difference grid to each SPH node in order to improve the description of the pore water evolution in the propagating mixture. The results obtained by the performed simulations are in agreement with the documentation obtained through the UK National Archive (Aberfan flowslide) and the International Commission of large Dams (Gypsum flowslide).
KW - Aberfan flowslide
KW - SPH
KW - Landslide propagation modelling
KW - Perzyna viscoplasticity
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410493
DO - https://doi.org/10.3390/ma10050562
SN - 1996-1944
VL - 10
IS - 5
SP - 562, 1
EP - 562, 21
AN - OPUS4-41049
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Daly, M.
A1 - Burnett, T. L.
A1 - Pickering, E. J.
A1 - Tuck, O. C. G.
A1 - Léonard, Fabien
A1 - Kelley, R.
A1 - Withers, P. J.
A1 - Sherry, A. H.
T1 - A multi-scale correlative investigation of ductile fracture
N2 - The use of novel multi-scale correlative methods, which involve the coordinated characterisation of matter across a range of length scales, are becoming of increasing value to materials scientists. Here, we describe for the first time how a multi-scale correlative approach can be used to investigate the nature of ductile fracture in metals. Specimens of a nuclear pressure vessel steel, SA508 Grade 3, are examined following ductile fracture using medium and high-resolution 3D X-ray computed tomography (CT) analyses, and a site-specific analysis using a dual beam plasma focused ion beam scanning electron microscope (PFIB-SEM). The methods are employed sequentially to characterise damage by void nucleation and growth in one volume of interest, allowing for the imaging of voids that ranged in size from less than 100 nm to over 100 mm. This enables the examination of voids initiated at carbide particles to be detected, as well as the large voids initiated at inclusions. We demonstrate that this multi-scale correlative approach is a powerful tool, which not only enhances our understanding of ductile failure through detailed characterisation of microstructure, but also provides quantitative information about the size, volume fractions and spatial distributions of voids that can be used to inform models of failure. It isfound that the vast majority of large voids nucleated at MnS inclusions, and that the volume of a void varied according to the volume of its initiating inclusion raised to the power 3/2. The most severe voiding was concentrated within 500 mm of the fracture surface, but measurable damage was found to extend to a depth of at least 3 mm. Microvoids associated with carbides (carbide-initiated voids) were found to be concentrated around larger inclusion-initiated voids at depths of at least 400 mm. Methods for quantifying X-ray CT void data are discussed, and a procedure for using this data to calibrate parameters in the Gurson-Tvergaard Needleman (GTN) model for ductile failure is also introduced.
KW - Gurson model
KW - SA508
KW - Correlative tomography
KW - Void nucleation & growth
KW - X-ray computed tomography
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-414547
UR - http://www.sciencedirect.com/science/article/pii/S1359645417302203?via%3Dihub
DO - https://doi.org/10.1016/j.actamat.2017.03.028
VL - 130
SP - 56
EP - 68
PB - Elsevier
AN - OPUS4-41454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tammas-Williams, S.
A1 - Zhao, H.
A1 - Léonard, Fabien
A1 - Derguti, F.
A1 - Todd, I.
A1 - Prangnell, P.B.
T1 - XCT analysis of the influence of melt strategies on defect population in Ti-6Al-4V components manufactured by Selective Electron Beam Melting
N2 - Selective Electron Beam Melting (SEBM) is a promising powder bed Additive Manufacturing technique for near-net-shape manufacture of high-value titanium components. However without post-manufacture HIPing the fatigue life of SEBM parts is currently dominated by the presence of porosity. In this study, the size, volume fraction, and spatial distribution of the pores in model samples have been characterised in 3D, using X-ray Computed Tomography, and correlated to the process variables. The average volume fraction of the pores (b0.2%) was measured to be lower than that usually observed in competing processes, such as selective laser melting, but a strong relationship was found with the differentbeamstrategies used to contour ,and infill by hatching, a part section. The majority of pores were found to be small spherical gas pores, concentrated in the infill hatched region; this was attributed to the lower energy density and less focused beam used in the infill strategy allowing less opportunity for gas bubbles to escape the melt pool. Overall, increasing the energy density or focus of the beam was found to correlate strongly to a reduction in the level of gas porosity. Rarer irregular shaped pores were mostly located in the contour region and have been attributed to a lack of fusion between powder particles.
KW - Titanium
KW - Additive Manufacture
KW - Selective Electron Beam Melting
KW - Pores
KW - X-ray computed tomography
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-416577
UR - http://www.sciencedirect.com/science/article/pii/S104458031500039X?via%3Dihub
DO - https://doi.org/10.1016/j.matchar.2015.02.008
VL - 102
SP - 47
EP - 61
CY - Materials Characterization
AN - OPUS4-41657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, Anja
A1 - Kranzmann, Axel
A1 - Wolthusen, Helmut
T1 - Unusual Corrosion Behavior of 1.4542 Exposed a Laboratory Saline Aquifer Water CCS-Environment
N2 - Differently heat treated coupons of 1.4542 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h - 8000 h in an a) water saturated supercritical CO2 and b) CO2-saturated synthetic aquifer environment similar to on-shore CCS-sites in the Northern German Basin. Surface corrosion layers are homogeneous but unusually discontinuously ellipsoidal. After 8000 h at 100 bar maximum corrosion rate in the liquid phase is approximately 0.014 mm/year, with normalizing providing best corrosion resistance and approximately 0.003 mm/year in the supercritical phase where hardening+tempering at 670 °C leads to lowest corrosion rates.
KW - CO2-storage
KW - Supercritical CO2
KW - Steel
KW - Pipeline
KW - Corrosion
KW - CCS
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418472
DO - https://doi.org/10.1016/j.egypro.2017.03.1679
VL - 114
SP - 5229
EP - 5240
PB - Elsevier Ltd.
AN - OPUS4-41847
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Taabache, Soraya
A1 - Bertin, Annabelle
T1 - Vesicles from amphiphilic dumbbells and Janus dendrimers: bioinspired self-assembled structures for biomedical applications
N2 - The current review focuses on vesicles obtained from the self-assembly of two types of dendritic macromolecules, namely amphiphilic Janus dendrimers (forming dendrimersomes) and amphiphilic dumbbells. In the first part, we will present some synthetic strategies and the various building blocks that can be used to obtain dendritic-based macromolecules, thereby showing their structural versatility. We put our focus on amphiphilic Janus dendrimers and amphiphilic dumbbells that form vesicles in water but we also encompass vesicles formed thereof in organic solvents. The second part of this review deals with the production methods of these vesicles at the nanoscale but also at the microscale. Furthermore, the influence of various parameters (intrinsic to the amphiphilic JD and extrinsic—from the environment) on the type of vesicle formed will be discussed. In the third part, we will review the numerous biomedical applications of these vesicles of nano- or micron-size.
KW - Janus dendrimers
KW - Amphiphilic dumbbells
KW - Self-assembled structures
KW - Dendrimersomes
KW - Artificial cells
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418245
DO - https://doi.org/10.3390/polym9070280
SN - 2073-4360
VL - 9
IS - 7
SP - Article 280, 1
EP - 36
AN - OPUS4-41824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, Susann
A1 - Schröter, Maria-Astrid
A1 - Hahn, Marc Benjamin
A1 - Solumon, Tihomir
A1 - Strum, Heinz
A1 - Kunte, Hans-Jörg
T1 - Ectoine can enhance structural changes in DNA in vitro
N2 - Strand breaks and conformational changes of DNA have consequences for the physiological role of DNA. The natural protecting molecule ectoine is beneficial to entire bacterial cells and biomolecules such as proteins by mitigating detrimental effects of environmental stresses. It was postulated that ectoine-like molecules bind to negatively charged spheres that mimic DNA surfaces. We investigated the effect of ectoine on DNA and whether ectoine is able to protect DNA from damages caused by ultraviolet radiation (UV-A). In order to determine different isoforms of DNA, agarose gel electrophoresis and atomic force microscopy experiments were carried out with plasmid pUC19 DNA. Our quantitative results revealed that a prolonged incubation of DNA with ectoine leads to an increase in transitions from supercoiled (undamaged) to open circular (single-strand break) conformation at pH 6.6. The effect is pH dependent and no significant changes were observed at physiological pH of 7.5. After UV-A irradiation in ectoine solution, changes in DNA conformation were even more pronounced and this effect was pH dependent. We hypothesize that ectoine is attracted to the negatively charge surface of DNA at lower pH and therefore fails to act as a stabilizing agent for DNA in our in vitro experiments.
KW - Ectoine
KW - DNA
KW - UV radiation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413139
DO - https://doi.org/10.1038/s41598-017-07441-z
VL - 7
IS - 1
SP - Article 7170, 1
EP - 10
AN - OPUS4-41313
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonse, Jörn
T1 - Scattering on scattering
N2 - Ultrafast experiments can reveal the spatiotemporal dynamics of nanostructure formation via scattering in background-free optical dark-field microscopy.
KW - Ultrafast microscopy
KW - Scattering
KW - Darkfield microscopy
KW - Laser ablation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411596
DO - https://doi.org/10.1038/lsa.2017.88
SN - 2047-7538
VL - 6
SP - e17088, 1
EP - 2
PB - Springer Nature
AN - OPUS4-41159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kasch, Thomas
A1 - Binder, Christian
A1 - Herrmann, Peter
A1 - Brock, Thomas
A1 - Heise, J.
ED - Rockland, U.
T1 - Einfluss von Keramikbeschichtungen auf das Abbrandverhalten metallischer Werkstoffe in hochverdichtetem Sauerstoff
N2 - Nach nationalen und internationalen Vorschriften müssen
Armaturen und Anlagenteile für hoch verdichteten Sauerstoff
ausbrennsicher sein. Diese Forderung kann technisch dadurch
erreicht werden, dass sicherheitstechnisch geeignete
nichtmetallische und metallische Werkstoffe verwendet werden.
Für die Auswahl geeigneter metallischer Werkstoffe sind
der Verwendungszweck der Armatur, die Betriebsbedingungen
sowie werkstoffspezifische Parameter zu berücksichtigen.
Einige metallische Werkstoffe besitzen gute Materialeigenschaften,
lassen sich leicht be- bzw. verarbeiten und
sind kostengünstig in der Beschaffung, dürfen aber aufgrund
ihres ungünstigen Abbrandverhaltens in Sauerstoff nicht eingesetzt
werden. Es besteht daher ein großes Interesse, den
sicherheitstechnischen Beschränkungen dieser Werkstoffe
durch geeignete Maßnahmen entgegenzuwirken. Eine mögliche
Lösung stellt die Beschichtung dieser Werkstoffe beispielsweise
mit Keramik dar, um den unmittelbaren Kontakt
mit dem Sauerstoff zu verhindern. Um den Einfluss dieser
Keramikschichten auf das Abbrandverhalten metallischer
Werkstoffe zu untersuchen, wird die im Standard ASTM G124
[1] beschriebene Apparatur und das in der einschlägigen
Literatur beschriebene Bewertungsverfahren verwendet. Die
Ergebnisse zeigen, dass für keramikbeschichtete metallische
Werkstoffe ein Abbrand erst bei höheren Sauerstoffdrücken
erfolgt.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48462
SP - 25
EP - 27
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4846
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Knorr, Annett
A1 - Rockland, Ulrike
A1 - Steinbach, J.
ED - Rockland, U.
T1 - Sicherheitstechnische Bewertung nach der TRAS 410 am Beispiel einer Perestersynthese
N2 - Die Technische Regel für Anlagensicherheit (TRAS) 410 mit
dem Titel "Erkennen und Beherrschen exothermer Reaktionen"
stellt im Rahmen der Betrachtung der thermischen
Prozesssicherheit eine Anleitung zur systematischen Erarbeitung
von Gefahren bei chemischen Stoffumwandlungen
im Industriemaßstab dar. Sie unterstützt bei der Bewertung
der Gefahren und bei der Erstellung von Maßnahmen, um
Störfälle zu verhindern. Am Beispiel der exotherm ablaufenden
Synthese von tert.-Butylperoxypivalat, einem organischen
Peroxid, wird die Vorgehensweise dargestellt. Organische
Peroxide sind als thermisch instabile Verbindungen bekannt
und besitzen dadurch ein zusätzliches Gefahrenpotential.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48504
SP - 43
EP - 48
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4850
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Aris, Stephan
ED - Rockland, U.
T1 - Zertifizierung nach Druckgeräte-Richtlinien und Überschneidung mit anderen Richtlinien
N2 - Die BAM ist als Benannte Stelle im Rahmen der europäischen
Richtlinien 97/23/EG über Druckgeräte (PED) [1] und
1999/36/EG über ortsbewegliche Druckgeräte (TPED) [2] bei
der Zertifizierung von Ausrüstungsteilen für Druckgefäße (PED
und TPED), Baugruppen (PED) und der Neubewertung von
Baumustern (TPED) tätig. In diesem Beitrag wird die Zertifizierung
einschließlich der dabei gewonnenen Erfahrungen
und in der Praxis auftretenden Problemen auf Seiten der
Hersteller und Benannten Stellen bei der Zertifizierung nach
diesen europäischen Richtlinien vorgestellt. Die wesentlichen
Probleme ergeben sich aus der Zuordnung der Druckgeräte
zu entsprechenden Kategorien innerhalb der Richtlinien und
aus der Überschneidung mit anderen europäischen und
nationalen Richtlinien.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48522
SP - 49
EP - 55
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4852
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rodner, Hans-Jochen
ED - Rockland, U.
T1 - Historie und Perspektive des Freiversuchsgeländes Horstwalde
N2 - Neben dem Stammgelände in Berlin Zehlendorf-Steglitz,
besitzt die Bundesanstalt für Materialforschung und -prüfung
(BAM) seit Mitte der 90ziger Jahre noch weitere Liegenschaften
in und bei Berlin. Zweiggelände befinden sich in Berlin,
in Zehlendorf-Steglitz und im Wissenschaftspark (WISTA) in
Adlershof.
Von besonderer Bedeutung ist das 12 km2 große Freiversuchsgelände
mit einem Sprengplatz von 400 m Durchmesser
für Brand- und Explosionsversuche bis 150 kg TNT
in Horstwalde, das ca. 50 km südlich von Berlin entfernt ist.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48540
SP - 57
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4854
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Michael-Schulz, Heike
ED - Rockland, U.
T1 - Ammoniumnitrat als Gefahrstoff
N2 - Die Diskussionen mit Fachleuten im Rahmen der Änderung
der Seveso-II-Richtlinie [1] haben gezeigt, dass sowohl Prufergebnisse
als auch Erfahrungen mit Ammoniumnitrat und
ammoniumnitrathaltigen Zubereitungen im Laufe der Zeit in
Vergessenheit geraten sind.
Die geanderte Seveso-II-Richtlinie berucksichtigt nunmehr
bei den Eintragungen fur Ammoniumnitrat und ammoniumnitrathaltige
Zubereitungen und den damit verbundenen
Mengenschwellen deren gefahrliche Eigenschaften.
Auf nationaler und internationaler Ebene werden immer wieder
Diskussionen bezuglich der gefahrlichen Eigenschaften
dieser Produkte, den Einflussfaktoren, den Prufmethoden
und deren Aussagefahigkeit gefuhrt.
Im folgenden sollen einige Prufmethoden und Einflussgro©¬en
auf die gefahrlichen Eigenschaften von Ammoniumnitrat und
ammoniumnitrathaltigen Zubereitungen vorgestellt werden.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48403
SP - 13
EP - 17
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4840
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lohrer, Christian
A1 - Schmidt, Martin
A1 - Krause, Ulrich
ED - Rockland, U.
T1 - Brandgefahren bei der Schüttgutlagerung - Einfluss von Inertgasen und Feuchte
N2 - Seit langer Zeit ist bekannt, dass ungünstige Lagerungsbedingungen
bei brennbaren Schüttgütern und Stäuben zur
Selbstentzündung führen können. Die meisten Studien zu
diesem Thema beziehen sich allerdings auf Umgebungsbedingungen
(d. h. mit einem Sauerstoff-Volumenanteil von
21 % in der Schüttungsumgebung). In einigen technischen
Anwendungen jedoch wird brennbares Schüttgut oder Staub
unter einer Gasatmosphäre mit reduziertem Sauerstoff-
Volumenanteil gelagert und verarbeitet (Inertisierung). Dabei
ist zunächst nicht klar, bis zu welchem Ausmaß der Sauerstoff-
Volumenanteil reduziert werden muss, um bei einer
vorgegebenen Lagerungstemperatur Selbstentzündung auszuschließen.
Neben dem Sauerstoffvolumenanteil können
auch der Feuchtegehalt der Schüttung sowie die relative Luftfeuchtigkeit
in der Schüttungsumgebung den Vorgang der
Selbstentzündung beeinflussen.
Die hier vorgestellten experimentellen Untersuchungen beschreiben
zum einen den Einfluss des Sauerstoff-Volumenanteils
auf die Selbstentzündungstemperatur (SET) von
Schüttgütern und Stäuben. Es wurde beobachtet, dass die
SET mit abnehmendem Sauerstoff-Volumenanteil in der
Schüttungsumgebung anstieg. Jedoch traten auch bei sehr
kleinem Sauerstoff-Volumenanteil noch signifikante Temperaturerhöhungen
in den untersuchten Proben auf.
Zum zweiten wurde der Einfluss der Feuchte auf die SET
untersucht. Dabei konnte gezeigt werden, dass unterkritisch
gelagerte Schüttungen durch Kondensation von Wasserdampf
oder Zugabe von Wasser auf die Oberfläche der
Schüttung in einen überkritischen Zustand gebracht werden
konnten.
Neben den experimentellen Untersuchungen wurde ein numerisches
Modell entwickelt, mit dessen Hilfe sich der
Selbsterwärmungsprozess bis hin zur Zündung von Schüttgütern
berechnen lässt. Anwendungen findet dieses Modell
für die Lagerung von Schüttgütern, Stäuben, Feststoffen
sowie Abfällen.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48437
SP - 19
EP - 23
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4843
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Oertzen, Alexander
A1 - Kurth, Lutz
ED - Rockland, U.
T1 - Modellgebäude: 1,5-kg-Satz. Auswirkungen einer unbeabsichtigten Explosion in einem in ausblasebauweise gebauten Arbeitsraum
N2 - Die BAM verfügt auf ihrem Versuchsgelände in Horstwalde
über ein Modellgebäude, das in der gleichen Weise aufgebaut
ist, wie Gebäudeteile, die in der Explosivstoff verarbeitenden Industrie eingesetzt werden.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48568
SP - 59
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4856
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fourier, Bianca
A1 - Kebben, Jochen
A1 - Michael-Schulz, Heike
ED - Rockland, U.
T1 - Sprengkammer: 4-Zoll-Stahl-Rohr. Detonationstest für Ammoniumnitrat und ammoniumnitrathaltige Zubereitung gemäß Anhang III der Verordnung (EG) Nr. 2003/2003
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48585
SP - 61
EP - 62
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4858
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - von Oertzen, Alexander
A1 - Kurth, Lutz
A1 - Rodner, Hans-Jochen
ED - Rockland, U.
T1 - Brandwallanlage: UN-6(c)-Test, sowie nach SprengLR 010, Prüfung D
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48605
SP - 63
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4860
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishra, Kirti Bhushan
A1 - Wehrstedt, Klaus-Dieter
T1 - An efficient and clean fuel for high temperature process industries
N2 - The use of energetic materials as a main fuel in high temperature process
industries are not known to the scientific community as such. This paper
highlights some of the features and advantages of using organic peroxides
especially di-tert-butyl peroxide (DTBP) in high temperature process industries.
The feasibility of using DTBP as a main or supporting fuel in process industries
have also been justified with the help of Computational Fluid Dynamics (CFD)
simulations. For peroxides requirement of less fuel and air for the same amount
of heat flux has been shown. The resulted emission from the combustion of
DTBP is also discussed.
T2 - 11th Conference on Energy for a Clean Environment
CY - Lisbon, Portugal
DA - 2011-07-05
KW - Energetic materials
KW - Process industries
KW - Organic peroxide
KW - Di-tert-butylperoxide (DTBP)
KW - CFD simulation
KW - Emission
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-247071
SP - 1
EP - 10
AN - OPUS4-24707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mishra, Kirti Bhushan
A1 - Wehrstedt, Klaus-Dieter
T1 - Combustion of peroxy-fuels
N2 - The diffusion flames of organic peroxides exhibit quite different characteristics than hydrocarbons. What makes them interesting to study is their fast burning behaviour. As a result the flame temperature enhances and so does the thermal radiation. Due to all these they demand safe handling during processing. However, they can be utilised at several places in different industries where a fuel with fast burning, high temperature and intense radiation are desired. Some of the possibilities to use them as a main or supporting fuel in a wide range of industrial utilities are the major content of this paper.
T2 - ERCOFTAC conference - Highly resolved experimental and numerical diagnostics for turbulent combustion
CY - Rouen, France
DA - 25.05.2011
KW - Energetic materials
KW - Process industries
KW - Organic peroxide
KW - Di-tert-butyl peroxide (DTBP)
KW - CFD simulation
KW - Emission
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-247083
SP - 1
EP - 5
AN - OPUS4-24708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schlichting, Joachim
A1 - Ziegler, Mathias
A1 - Pelkner, Matthias
A1 - Maierhofer, Christiane
A1 - Kreutzbruck, Marc
T1 - Kameragestütztes Flying-Spot-Verfahren zur Risserkennung
N2 - In dieser Arbeit wird ein kameragestütztes Verfahren zur Flying-
Spot-Thermografie vorgestellt. Die Anregung wird über einen Diodenlaser mit einem optischen Scanner realisiert. Bei der Auswertung kommt ein effizienter und robuster Algorithmus zum Einsatz, der direkt auf die mit der Kamera aufgenommene Thermografiesequenz angewendet werden kann, ohne auf eine
Synchronisation zwischen Kamera und Lasersystem angewiesen zu sein. Daher eignet sich diese Herangehensweise besonders zur Nachrüstung bestehender Thermografiesysteme.
Die prinzipielle Eignung dieser Methode wird anhand einer Messung an einem Schienenstück mit Rollkontaktermüdungsrissen gezeigt. Als Referenzverfahren werden die Magnetpulverprüfung und eine auf GMR (Giant Magnetoresistance)- Sensoren basierende Streufeldmessung herangezogen. Mit dem thermografischen Verfahren konnten sämtliche enthaltenen Fehler erkannt werden. Dabei wurden Risse im mm-Abstand getrennt nachgewiesen, was etwa der geometrischen Auflösung der eingesetzten Kamera entspricht.
T2 - Thermographie-Kolloquium 2011
CY - Stuttgart, Germany
DA - 29.09.2011
KW - Flying-Spot Thermografie
KW - Diodenlaser
KW - Rissortung
KW - Magnetpulverprüfung
KW - GMR-Sensoren
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246220
SN - 978-3-940283-36-8
IS - DGZfP-BB 130 (Vortrag 09)
SP - 1
EP - 6
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24622
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schlichting, Joachim
A1 - Steinfurth, Henrik
A1 - Maierhofer, Christiane
A1 - Kreutzbruck, Marc
T1 - Thermografische Prüfung von Punktschweißverbindungen
N2 - Vor allem in der Automobilindustrie wird das Widerstandpunktschweißen im großen Unfang zur Verbindung von Blechen im Karosseriebau verwendet. Durch den anhaltenden Trend zum Leichtbau und den immer höheren Anforderungen an die passive Sicherheit kommt es hier zu einem verstärkten Einsatz innovativer hochfester Stähle. Obwohl es sich beim Punktschweißen um ein lange erprobtes Verfahren handelt, das sich anhand der Prozessparameter und regelmäßiger zerstörender Prüfung überwachen lässt, ist durch diese Entwicklung die Suche nach geeigneten zerstörungsfreien Prüfverfahren wieder aktuell. Wegen der hohen Produktionsgeschwindigkeiten in der automatisierten Fertigung muss sich das Prüfverfahren für eine hundertprozentige Prüfung vollautomatisch mit der typischen Taktrate von etwa einem Hertz durchführen lassen.
In dieser Arbeit wird zuerst die prinzipielle Durchführbarkeit der thermografischen Prüfung von Punktschweißverbindungen an speziell präparierten Proben überprüft. Auf dieser Grundlage wird eine Serienuntersuchung an 75 Proben, die sich auf drei Gruppen von Schweißparametern aufteilen und neben optimal geschweißten Proben typische Fehlerbilder repräsentieren, eine Serienuntersuchung gezeigt. Hierzu wird eine Blitzlichtanregung in Transmissionsanordnung verwendet.
Es kann gezeigt werden, dass sich mit einer geeigneten Datenaufbereitung die einzelnen Gruppen sicher trennen lassen. Durch eine statistische Bewertung der Ergebnisse kann unter Verwendung eines angepassten Gütekriteriums die Trennschärfe noch deutlich erhöht werden.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Aktive Thermografie
KW - Blitzlichtanregung
KW - Punktschweißverbindung
KW - Transmissionsmessung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-249915
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.1.C.3)
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24991
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Regina
A1 - Kreutzbruck, Marc
A1 - Maierhofer, Christiane
T1 - Numerische Verfahren für die aktive Thermografie zur Untersuchung von Rückwandgeometrien
N2 - In diesem Beitrag werden numerische Verfahren zur Erkennung und Charakterisierung von Fehlstellen, Schichtdicken, Wanddicken und Inhomogenitäten mittels aktiver Thermografie vorgestellt. Eine uantitative Beurteilung der nicht immer zugänglichen Rückwand eines Bauteils (Minderdicken) ist durch Inversion thermografischer Messdaten möglich. Diese quantitativen Informationen können durch iterative Methoden vom Gauß-Newton-Typ (Inversion) gewonnen werden. Als reale Prüfobjekte werden ca. 2 cm dicke PVC-Platten mit örtlich variierender Rückwandgeometrie untersucht. Die Erwärmung erfolgt mit
Blitzlampen, welche die PVC-Platte kurzzeitig um mehrere K erwärmt. Ein wichtiger Teil der Inversion ist die Simulation des Experiments, welche mit Finite-Elemente-Methoden (FEM) in 2D realisiert wird. Da Inversion und active Thermografie automatisierbar sind, bietet die Kombination breite Anwendungsgebiete innerhalb der Industrie.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Deutschland
DA - 30.05.2011
KW - Inversion
KW - Aktive thermografie
KW - Wanddicke
KW - Rückwand
KW - Minderdicken
KW - Schichtdicken
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-252812
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (P45)
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25281
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reimund, Verena
A1 - Pelkner, Matthias
A1 - Neubauer, Andreas
A1 - Thomas, Hans-Martin
A1 - Kreutzbruck, Marc
T1 - Automatische Detektion von Rissen in Stahlbauteilen unter Verwendung von GMR-Sensoren bei der magnetischen Streuflussprüfung
N2 - GMR-Sensor Arrays ermöglichen eine örtlich hoch aufgelöste Messung magnetischer Streufeldamplituden an Stahlbauteilen, bei der abhängig von der Größe der zu prüfenden Oberfläche erhebliche Datenmengen erzeugt werden.
Eine automatische Detektion von Rissen kann anschließend mittels digitaler Bildverarbeitung erreicht werden, welche hauptsächlich auf einer Kantenerkennung basiert. Diese wurde anhand einer Magnetometer-Messung getestet, die an einem zylindersymmetrischem Bauteil mit funkenerosiv eingebrachten Rissen geringer Tiefe durchgeführt wurde. Die erzielte Selektion der Defekte wird für eine angestrebte Rekonstruktion der Defektgeometrie benötigt.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Deutschland
DA - 30.05.2011
KW - GMR-Sensor
KW - Streuflussprüfung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253451
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Mo.3.C.4)
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25345
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gohlke, Dirk
A1 - Kotschate, Daniel
A1 - Heckel, Thomas
T1 - Visualisierung der Volumenmessdaten von hochauflösenden Ultraschalltauchtechnikprüfungen
N2 - Die heutigen Anforderungen an Bauteile und deren Materialien werden immer höher. Somit steigen auch die Anforderungen an die notwendigen Prüfverfahren zur Qualitätsbestimmung bzw. –erhaltung. Durch den optimierten Einsatz von mechanisierten Prüfverfahren und der Verwendung von Visualisierungsalgorithmen wird es möglich, Prüfergebnisse mehrdimensional und farbcodiert z.B. als Überblicksansicht über das Volumen des geprüften Bauteils zu bekommen.
Bei der hochauflösenden Volumenprüfung eines Bauteils mittels Ultraschall-Tauchtechnikverfahren, bei dem anstelle einer einfachen Ja/Nein – Aussage eine detaillierte Analyse erforderlich ist, ist es notwendig, alle Messdaten, d.h. jedes A-Bild an jedem Ort, zu speichern.
Bei der Auswertung der Daten werden vorwiegend 2D-Darstellungen, wie z.B. das C-Bild der gescannten Fläche, B-Bilder der Scan- und Index-Ebene sowie das A-Bild an der jeweiligen Position verwendet. Um sich z.B. ein Überblick über das Volumen zu verschaffen, werden die B-Bilder der jeweiligen Ebene gescrollt. Bei diesem Verfahren erhält man zwar eine genaue Aussage in den einzelnen Ebenen, aber doch wenig Informationen über die Lage der Anzeigen im Prüfvolumen.
Eine 3D-Visualisierung der Volumenmessdaten liefert unter Berücksichtigung der Bauteilgeometrie und einer Farbcodierung der Amplitudenwerte eine übersichtliche Darstellung über Lage, Größe und Verteilung der Anzeigen im Volumen des Bauteils.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Volumenprüfung
KW - Tauchtechnik
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253859
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Poster 61)
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25385
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heckel, Thomas
A1 - Boehm, Rainer
A1 - Gohlke, Dirk
A1 - Völz, Uwe
T1 - Analyseprüfung von Eisenbahnradsatzwellen mit Ultraschall
N2 - Die wiederkehrende zerstörungsfreie Prüfung von längs gebohrten
Eisenbahnradsatzwellen mit Ultraschall erfolgt im eingebauten Zustand aus der Wellenbohrung heraus. Neben den aufzufindenden Fehleranzeigen erzeugt aufgrund der geometrischen Bedingungen der Radsatzwelle hierbei jeder Querschnittsübergang eine umlaufende Formanzeige in der Ergebnisdarstellung. Durch den Prozess des Aufschrumpfens der Radscheiben auf die Sitze können weiterhin örtlich statistisch verteilte Bereiche im Sitz entstehen, die bei der Ultraschallprüfung Anzeigen hervorrufen, die so genannten Scheinanzeigen. Insbesondere in den Bereichen der Querschnittsübergänge ist zum einen die Prüfsituation sehr komplex, zum anderen ist hier die Wahrscheinlichkeit für eine Rissbildung am höchsten. Bei der Befundanalyse stößt die derzeit verwendete Prüftechnik in diesen Bereichen an ihre Grenzen, so dass nicht immer eine eindeutige Prüfaussage erfolgen kann. Im Bericht werden Lösungsansätze für Analyseverfahren vorgestellt, die auf Basis der Gruppenstrahlertechnik bzw. mit Fokusprüfköpfen in Verbindung mit dem Einsatz von Signalverarbeitung vielversprechende Ergebnisse zur Optimierung dieser Situation aufzeigen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Eisenbahnradsatzwellen
KW - Radsatzwellen
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253863
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.2.A.3)
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25386
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neumann, Patrick P.
A1 - Asadi, S.
A1 - Hernandez Bennetts, V.
A1 - Lilienthal, A.J.
A1 - Bartholmai, Matthias
T1 - Monitoring of CCS areas using micro unmanned aerial vehicles (MUAVs)
N2 - Carbon capture & storage (CCS) is one of the most promising technologies for greenhouse gas (GHG) management. However, an unsolved issue of CCS is the development of appropriate long-term monitoring systems for leak detection of the stored CO2. To complement already existing monitoring infrastructure for CO2 storage areas, and to increase the granularity of gas concentration measurements, a quickly deployable, mobile measurement device is needed. In this paper, we present an autonomous gas-sensitive micro-drone, which can be used to monitor GHG emissions, more specifically, CO2. Two different measurement strategies are proposed to address this task. First, the use of predefined sensing trajectories is evaluated for the task of gas distribution mapping using the micro-drone. Alternatively, we present an adaptive strategy, which suggests sampling points based on an artificial potential field (APF). The results of real-world experiments demonstrate the feasibility of using gas-sensitive micro-drones for GHG monitoring missions. Thus, we suggest a multi-layered surveillance system for CO2 storage areas.
T2 - GHGT 11 - Greenhouse gas control technologies conference
CY - Kyoto, Japan
DA - 18.11.2012
KW - Gas-sensitive micro-drone
KW - Gas distribution mapping
KW - Sensor planning
KW - Artificial potential field
KW - CCS
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-289119
DO - https://doi.org/10.1016/j.egypro.2013.06.320
SN - 1876-6102
VL - 37
SP - 4182
EP - 4190
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-28911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heckel, Thomas
A1 - Zerbst, Uwe
T1 - Einfluss von Save Life- und Schadenstoleranzkonzepten auf die ZfP von Eisenbahnradsatzwellen
N2 - Die Sicherheitsauslegung von Radsatzwellen sieht ein abgestuftes Konzept aus dauer- und betriebsfester Konstruktion und regelmäßigen zerstörungsfreien Prüfungen vor. Der Vortrag gibt einen Überblick über diese Aspekte unter Einbeziehung moderner Auslege- und Prüfverfahren. Ein besonderer Schwerpunkt liegt dabei auf potentiellen Fragen der zerstörungsfreien Prüfung nicht nur bei der Spezifizierung belastbarer Inspektionsintervalle sondern auch bei der Gewährleistung der Basissicherheit im Rahmen von Betriebsfestigkeitsbetrachtungen. Speziell angesprochen werden Fragen wie der Einfluss und Nachweis von nichtmetallischen Einschlüssen in Stahl, Korrosionsgrübchen und Steinschlagkerben aus dem Betrieb sowie die Detektionswahrscheinlichkeit von Rissen in Abhängigkeit von der Rissgröße und der Belastung auf den Rissufern unter Berücksichtigung des Funktionsumfanges von Prüfsystemen.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-286204
SN - 978-3-940283-49-8
IS - Mi.1.A.1
SP - 1
EP - 7
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28620
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Röllig, Mathias
A1 - Steinfurth, Henrik
A1 - Ziegler, Mathias
T1 - Untersuchung von Hochleistungs-LEDs für den Einsatz in der zerstörungsfreien Prüfung mittels Thermografie
N2 - Für die optische Erwärmung von Prüfteiloberflächen sind Blitz- und Halogenlampen Stand der Technik. Der Vorteil dieser Wärmequellen liegt in ihren relativ geringen Anschaffungskosten bei gleichzeitig hohen Leistungsdichten am Prüfobjekt. Nachteilig ist bei den Halogenlampen die Limitierung der möglichen Modulationsffequenz auf ca. 1 Hz für die Anwendung dieser Quelle in der Lockin-Thermografie. Blitzlampen bieten für gewöhnlich nur eine feste Blitzdauer bei einer geringen Taktrate. Beide Anregungsquellen müssen in Reflexionsanordnung mit Filtern betrieben werden um die entstehende thermische Eigenstrahlung als Störquelle zu eliminieren. Wir stellen Untersuchungen an Hochleistungs-LEDs für den Einsatz in der aktiven Thermografie vor. Diese Lichtquellen werden durch die rasante Entwicklung der möglichen Leistungsdichten nun auch für die thermografische ZfP interessant. Sie zeigen ähnlich dem Laser eine schmale und auf den Werkstoff abstimmbare spektrale Verteilung der Strahlungsleistung bei moderaten Kosten. Die zugrunde liegende Elektrolumineszenz generiert kaum Wärmestrahlung und ermöglicht dadurch die Prüfung während des Erwärmungsvorganges ohne größeren Aufwand. Modulationsfrequenzen über 100 Hz mit thermischen Eindringtiefen < 1 mm sind möglich. Dadurch qualifizieren sich die LEDs zur Anwendung in der Lockin-Thermografie von Metallen und zur oberflächennahen Prüfung von Schichtsystemen. Durch die fast verzögerungsffeie Reaktion der LED auf das steuernde Signal sind nahezu beliebige zeitliche Anregungsformen möglich. Mit solch flexiblen Anregungsformen ließen sich bereits bei den photothermischen Verfahren erfolgreich höhere Tiefenreichweiten und -auflösungen gegenüber den klassischen Methoden der monofrequenten Lockin - und energiereichen Kurzimpuls-Anregung erzielen. Untersuchungen dieser Möglichkeiten im praktischen Einsatz der HochleistungsLEDs werden vorgestellt und mit herkömmlichen Lichtquellen verglichen.
T2 - Thermographie-Kolloquium 2013
CY - Leinfelden-Echterdingen, Germany
DA - 2013-09-26
KW - Thermografie
KW - Hochleistungsleuchtdioden
KW - Hohe Prüfraten
KW - Schnelle Modulationsfrequenzen
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-293975
SN - 978-3-940283-52-8
VL - DGZfP-BB 143
SP - Vortrag 3, 1
EP - 8
AN - OPUS4-29397
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schraa, Lucas
A1 - Rodricks, Carol
A1 - Kalinka, Gerhard
A1 - Roetsch, Karl
A1 - Scheffler, Christina
A1 - Sambale, Anna
A1 - Uhlig, Kai
A1 - Stommel, Markus
A1 - Trappe, Volker
T1 - Characterisation and Modelling of the Fibre-Matrix Interface of Short Fibre Reinforced Thermoplastics using the Push-Out Technique
N2 - This study investigates the suitability of the single fibre push-out (SFPO) test for the determination of the interfacial shear strength (IFSS) of injection moulded short fibre reinforced thermoplastics. It includes a detailed description of the required sample preparation steps and the boundary conditions of the SFPO setup. Experimental SFPO tests were carried out on PA66 GF, PPA GF35 and PA6 GF50 materials. Furthermore, a finite element model was set up to simulate the behaviour of these materials during this test. The numerical results showed that the inhomogeneous stress distribution in the fibre-matrix interphase during the test causes the measured apparent IFSS to underestimate the true strength of the interphase. The simulations put the experimental results into perspective and provide valuable information for the further development of the test setup. This study therefore not only provides new insights into the interphase strength of injection moulded short fibre reinforced thermoplastics, but also an insight into local load conditions during testing and thus an indication of the true IFSS.
KW - GFRP
KW - Interface
KW - fibre matrix bond
KW - single fibre push-out
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626087
DO - https://doi.org/10.1016/j.compositesb.2025.112317
SN - 1879-1069
VL - 297
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-62608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte Bernardino, Carolina
A1 - Lee, Mihyun
A1 - Ren, Qun
A1 - Ruehle, Bastian
T1 - Facile Spray-Coating of Antimicrobial Silica Nanoparticles for High-Touch Surface Protection
N2 - The rising threat from infectious pathogens poses an ever-growing challenge. Metal-based nanomaterials have gained a great deal of attention as active components in antimicrobial coatings. Here, we report on the development of readily deployable, sprayable antimicrobial surface coatings for high-touch stainless steel surfaces that are ubiquitous in many healthcare facilities to combat the spread of pathogens. We synthesized mesoporous silica nanoparticles (MSNs) with different surface functional groups, namely, amine (MSN-NH2), carboxy (MSN-COOH), and thiol groups (MSN-SH). These were chosen specifically due to their high affinity to copper and silver ions, which were used as antimicrobial payloads and could be incorporated into the mesoporous structure through favorable host−guest interactions, allowing us to find the most favorable combinations to achieve antimicrobial efficacy against various microbes on dry or semidry high-touch surfaces. The antimicrobial MSNs were firmly immobilized on stainless steel through a simple two-step spray-coating process. First, the stainless steel surfaces are primed with sprayable polyelectrolyte solutions acting as adhesion layers, and then, the loaded nanoparticle dispersions are spray-coated on top. The employed polyelectrolytes were selected and functionalized specifically to adhere well to stainless steel substrates while at the same time being complementary to the MSN surface groups to enhance the adhesion, wettability, homogeneity, and stability of the coatings. The antimicrobial properties of the nanoparticle suspension and the coatings were tested against three commonly found pathogenic bacteria, Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli, as well as a fungal pathogen, Candida albicans. Especially MSN-SH loaded with silver ions showed excellent antimicrobial efficacy against all tested pathogens under application-relevant, (semi)dry conditions. The findings obtained here facilitate our understanding of the correlation between the surface properties, payloads, and antimicrobial activity and show a new pathway toward simple and easily deployable solutions to combat the spread of pathogens with the help of sprayable antimicrobial surface coatings.
KW - Mesoporous silica nanoparticles
KW - Thin films
KW - Antimicrobial coatings
KW - Spray-coating
KW - Infectious diseases
KW - Pathogen transmission
KW - High-touch surfaces
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626269
DO - https://doi.org/10.1021/acsami.4c18916
SN - 1944-8252
SP - 1
EP - 13
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-62626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishmastnehi, Moslem
A1 - Stawski, Tomasz M.
A1 - Eftekhari, Negar
A1 - Schneider, Kathrin P.
A1 - Vaccaro, Carmela
A1 - Aghajani, Iman
A1 - Grbanovic, Ana Marija
A1 - Korn, Lorenz
T1 - Unveiling the craftsmanship and knowledge behind iranian stuccoes (11th–14th centuries): New insights from an archaeometric perspective
N2 - Gypsum-based stucco decorations of 47 monuments in Iran, from the Seljuq to the Ilkhanid period (11th-14th centuries), were studied by multimodal analytical methods, including X-ray diffraction, X-ray fluorescence, scanning electron microscopy and image analysis to evaluate their composition properties. The assessment of results shows that stucco masters in those periods exerted control over the setting process of the gypsum-paste and its microstructure by adjusting water-to-plaster ratio, fine-clay addition, and by means of mechanical processing. Furthermore, the presence of anhydrite in the composition of stucco decorations located in the hot-desert climate of Iran provides evidence for the probability of gypsum-anhydrite transition, which has technical and preservation consequences for this less-investigated type of cultural materials.
KW - Gypsum
KW - Diffraction
KW - Anhydrite
KW - Calcium sulfate
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628406
DO - https://doi.org/10.1016/j.jas.2025.106199
SN - 1095-9238
VL - 177
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-62840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andrés Arcones, Daniel
A1 - Weiser, M.
A1 - Koutsourelakis, P.-S.
A1 - Unger, Jörg F.
T1 - Model bias identification for Bayesian calibration of stochastic digital twins of bridges
N2 - Simulation-based digital twins must provide accurate, robust, and reliable digital representations of their physical counterparts. Therefore, quantifying the uncertainty in their predictions plays a key role in making better-informed decisions that impact the actual system. The update of the simulation model based on data must then be carefully implemented. When applied to complex structures such as bridges, discrepancies between the computational model and the real system appear as model bias, which hinders the trustworthiness of the digital twin and increases its uncertainty. Classical Bayesian updating approaches aimed at inferring the model parameters often fail to compensate for such model bias, leading to overconfident and unreliable predictions. In this paper, two alternative model bias identification approaches are evaluated in the context of their applicability to digital twins of bridges. A modularized version of Kennedy and O'Hagan's approach and another one based on Orthogonal Gaussian Processes are compared with the classical Bayesian inference framework in a set of representative benchmarks. Additionally, two novel extensions are proposed for these models: the inclusion of noise-aware kernels and the introduction of additional variables not present in the computational model through the bias term. The integration of these approaches into the digital twin corrects the predictions, quantifies their uncertainty, estimates noise from unknown physical sources of error, and provides further insight into the system by including additional pre-existing information without modifying the computational model.
KW - Gaussian process
KW - KOH
KW - Bayesian updating
KW - Digital twins
KW - Uncertainty quantification
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615519
DO - https://doi.org/10.1002/asmb.2897
SN - 1526-4025
N1 - This work was supported by “C07 - Data driven model adaptation for identifying stochastic digital twins of bridges” from the Priority Program (SPP) 2388/1 “Hundred plus” of the German Research Foundation (Deutsche Forschungsgemeinschaft, DFG) - Project number 501811638.
VL - 417
IS - 3
SP - 1
EP - 26
PB - Wiley
CY - Chichester
AN - OPUS4-61551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ruehle, Bastian
T1 - Natural language processing for automated workflow and knowledge graph generation in self-driving labs
N2 - Natural language processing with the help of large language models such as ChatGPT has become ubiquitous in many software applications and allows users to interact even with complex hardware or software in an intuitive way. The recent concepts of Self-Driving Labs and Material Acceleration Platforms stand to benefit greatly from making them more accessible to a broader scientific community through enhanced user-friendliness or even completely automated ways of generating experimental workflows that can be run on the complex hardware of the platform from user input or previously published procedures. Here, two new datasets with over 1.5 million experimental procedures and their (semi)automatic annotations as action graphs, i.e., structured output, were created and used for training two different transformer-based large language models. These models strike a balance between performance, generality, and fitness for purpose and can be hosted and run on standard consumer-grade hardware. Furthermore, the generation of node graphs from these action graphs as a user-friendly and intuitive way of visualizing and modifying synthesis workflows that can be run on the hardware of a Self-Driving Lab or Material Acceleration Platform is explored. Lastly, it is discussed how knowledge graphs – following an ontology imposed by the underlying node setup and software architecture – can be generated from the node graphs. All resources, including the datasets, the fully trained large language models, the node editor, and scripts for querying and visualizing the knowledge graphs are made publicly available.
KW - Natural Language Processing
KW - Large Language Models
KW - Self-Driving Labs
KW - Materials Acceleration Platforms
KW - Workflows
KW - Nanomaterials
KW - Advanced Materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631947
UR - https://github.com/BAMresearch/MAPz_at_BAM/tree/main/Minerva-Workflow-Generator
DO - https://doi.org/10.1039/d5dd00063g
SN - 2635-098X
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwibbert, Karin
A1 - Richter, Anja
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Laser-Textured Surfaces: A Way to Control Biofilm Formation?
N2 - Bacterial biofilms pose serious problems in medical and industrial settings. One of the major societal challenges lies in the increasing resistance of bacteria against biocides used in antimicrobial treatments, e.g., via overabundant use in medicine, industry, and agriculture or cleaning and disinfection in private households. Hence, new efficient bacteria-repellent strategies avoiding the use of biocides are strongly desired. One promising route to achieve bacteria-repellent surfaces lies in the contactless and aseptic large-area laser-processing of technical surfaces. Tailored surface textures, enabled by different laser-processing strategies that result in topographic scales ranging from nanometers to micrometers may provide a solution to this challenge. This article presents a current state-of-the-art review of laser-surface subtractive texturing approaches for controlling the biofilm formation for different bacterial strains and in different environments. Based on specific properties of bacteria and laser-processed surfaces, the challenges of anti-microbial surface designs are discussed, and future directions will be outlined.
KW - Antibacterial surfaces
KW - Biofilms
KW - Laser processing
KW - Laser-induced periodic surface structures (LIPSS)
KW - Microbial adhesions
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588260
DO - https://doi.org/10.1002/lpor.202300753
SN - 1863-8899
SP - 1
EP - 41
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-58826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, C.
A1 - Schwibbert, Karin
A1 - Radunz, S.
A1 - Thiele, Dorothea
A1 - Laux, P.
A1 - Luch, A.
A1 - Tschiche, H.R.
T1 - ROS generating BODIPY loaded nanoparticles for photodynamic eradication of biofilms
N2 - Bacterial biofilms can pose a serious health risk to humans and are less susceptible
to antibiotics and disinfection than planktonic bacteria. Here, a novel method
for biofilm eradication based on antimicrobial photodynamic therapy utilizing
a nanoparticle in conjunction with a BODIPY derivative as photosensitizer was
developed. Reactive oxygen species are generated upon illumination with
visible light and lead to a strong, controllable and persistent eradication of
both planktonic bacteria and biofilms. One of the biggest challenges in biofilm
eradication is the penetration of the antimicrobial agent into the biofilm and
its matrix. A biocompatible hydrophilic nanoparticle was utilized as a delivery
system for the hydrophobic BODIPY dye and enabled its accumulation within the
biofilm. This key feature of delivering the antimicrobial agent to the site of action
where it is activated resulted in effective eradication of all tested biofilms. Here,
3 bacterial species that commonly form clinically relevant pathogenic biofilms
were selected: Escherichia coli, Staphylococcus aureus and Streptococcus
mutans. The development of this antimicrobial photodynamic therapy tool for
biofilm eradication takes a promising step towards new methods for the much
needed treatment of pathogenic biofilms.
KW - Biofilm
KW - Antimicrobials
KW - Photodynamic therapy
KW - BODIPY
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587588
DO - https://doi.org/10.3389/fmicb.2023.1274715
SN - 1664-302X
VL - 14
SP - 1
EP - 15
AN - OPUS4-58758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ecke, Alexander
A1 - Bell, Jérémy
A1 - Schneider, Rudolf
T1 - A three-dimensional microfluidic flow cell and system integration for improved electrochemical substrate detection in HRP/TMB-based immunoassays
N2 - Immunoassays, based on the recognition and capture of analytes by highly selective antibodies, are now used extensively in all areas of diagnostics, but the challenge is to further integrate them into online sensors. To improve the transition from laboratory immunoassays to immunosensors, we have developed a complete flow system, based on a microfluidic core flow cell to enable automated detection of one of the most commonly used immunoassay substrates, TMB, by chronoamperometry. The architecture and fluidic optimisation of the system showed that a specially designed 3D flow cell allows higher flow rates (500 μL min−1) than a standard enlarged microfluidic channel (50 μL min−1) resulting in a significantly shorter detection time of 30 seconds per sample and making the system more robust against interferences due to bubble formation in the chip. The electrochemical measurements showed an improved signal-to-noise ratio (SNR) and thus higher sensitivity for a model immunoassay for diclofenac (SNR = 59), compared to the analytical performance of a conventional laboratory microplate-based assay with optical detection (SNR = 19). In general, this system facilitates the conversion of any conventional immunoassay into an immunosensor with automatic and continuous detection.
KW - Microfluidic
KW - Immunoassay
KW - Electrochemical
KW - Mikrofluidik
KW - Immunassay
KW - Elektrochemie
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580159
DO - https://doi.org/10.1039/d3sd00095h
VL - 2
SP - 887
EP - 892
PB - Royal Society of Chemistry
CY - London, United Kingdom
AN - OPUS4-58015
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reuter, T.
A1 - Borges de Oliveira, F.
A1 - Abt, Ch.
A1 - Ballach, F.
A1 - Bartscher, M.
A1 - Bellon, Carsten
A1 - Dennerlein, F.
A1 - Fuchs, P.
A1 - Günnewig, O.
A1 - Hausotte, T.
A1 - Hess, J.
A1 - Kasperl, S.
A1 - Maass, N.
A1 - Kimmig, W.
A1 - Schielein, R.
A1 - von Schmid, M.
A1 - Suppes, A.
A1 - Wagner, G.
A1 - Watzl, Ch.
A1 - Wohlgemuth, F.
T1 - Introduction to “Realistic Simulation of real CT systems with a basic-qualified Simulation Software - CTSimU2“
N2 - The lack of traceability to meter of X-ray Computed Tomography (CT) measurements still hinders a more extensive acceptance of CT in coordinate metrology and industry. To ensure traceable, reliable, and accurate measurements, the determination of the task-specific measurement uncertainty is necessary. The German guideline VDI/VDE 2630 part 2.1 describes a procedure to determine the measurement uncertainty for CT experimentally by conducting several repeated measurements with a calibrated test specimen. However, this experimental procedure is cost and effort intensive. Therefore, the simulation of dimensional measurement tasks conducted with X-ray computed tomography can close these drawbacks. Additionally, recent developments towards a resource and cost-efficient production (“smart factory”) motivate the need for a corresponding numerical model of a CT system (“digital twin”) as well. As there is no standardized procedure to determine the measurement uncertainty of a CT system by simulation at the moment, the project series CTSimU was initiated, aiming at this gap. Concretely, the goal is the development of a procedure to determine the measurement uncertainty numerically by radiographic simulation. The first project (2019-2022), "Radiographic Computed Tomography Simulation for Measurement Uncertainty Evaluation - CTSimU" developed a framework to qualify a radiographic simulation software concerning the correct simulation of physical laws and functionalities. The most important outcome was a draft for a new guideline VDI/VDE 2630 part 2.2, which is currently under discussion in the VDI/VDE committee. The follow-up project CTSimU2 "Realistic Simulation of real CT systems with a basic-qualified Simulation Software" will deal with building and characterizing a digital replica of a specific real-world CT system. The two main targets of this project will be a toolbox including methods and procedures to configure a realistic CT system simulation and to develop tests to check if this replica is sufficient enough. The result will be a draft for a follow-up VDI/VDE guideline proposing standardized procedures to determine a CT system's corresponding characteristics and test the simulation (copy) of a real-world CT system which we call a "digital twin".
T2 - 12th Conference on Industrial Computed Tomography (iCT) 2023
CY - Fürth, Germany
DA - 27.02.2023
KW - dXCT
KW - X-ray computed tomography
KW - Simulation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589204
DO - https://doi.org/10.58286/27715
VL - 28
IS - 3
SP - 1
EP - 5
PB - NDT.net
AN - OPUS4-58920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reuter, T.
A1 - Wohlgemuth, F.
A1 - Bellon, Carsten
A1 - Hausotte, T.
T1 - Measurement-based Detector Characteristics for Digital Twins in aRTist 2
N2 - Various software products for the simulation of industrial X-ray radiography have been developed in recent years (e.g., aRTist 2, CIVA CT, Scorpius XLab, SimCT, Wilcore) and their application potential has been shown in numerous works. However, full systematic approaches to characterise a specific CT system for these simulation software products to obtain a truthful digital twin are still missing. In this contribution, we want to present two approaches to obtain realistic grey values in X-ray projections in aRTist 2 simulations based on measured projections. In aRTist 2, the displayed grey value of a pixel is based on the energy density incident on that pixel.
The energy density is calculated based on the X-ray tube spectrum, the attenuation between source and detector as well as an energy-dependent sensitivity curve of the detector. The first approach presented in this contribution uses the sensitivity curve as a free modelling parameter. We measured the signal response at different thicknesses of Al EN-AW6082 at different tube voltages (i.e., different tube spectra). We then regarded the grey values displayed by these projections as a data regression respectively an optimisation problem and obtained the sensitivity curve that is best able to reproduce the measured behaviour in aRTist 2. The resulting sensitivity curve does not necessarily hold physical meaning but is able to simulate the real system behaviour in the simulation software.
The second approach presented in this contribution is to estimate the sensitivity curve based on assumptions about the characteristics of the scintillation detector (e.g., scintillator material, scintillator thickness and signal processing characteristics). For this approach, a linear response function (linear relationship between the deposited energy per pixel and the resulting grey value) is assumed. If the detector characteristics, which affect the simulated deposited energy, are properly modelled, the slope and offset of the response function to match the measured grey values should be the same for different tube spectra. As the offset is constant and given by the grey values measured at no incident radiation, the slope is the remaining parameter to evaluate the success of the detector modelling. We therefore adapted the detector characteristics by changing the detector setup until the slope was nearly the same for all measured tube spectra. We are aware that the resulting parameters of the scintillator material and thickness might not be the real ones, but with those modelling parameters we are able to simulate realistic grey values in aRTist 2. Both of those approaches could potentially be a step forward to a full systematic approach for a digital twin of a real CT system in aRTist 2.
T2 - 20th World Conference on Non-Destructive Testing (WCNDT 2024)
CY - Incheon, South Korea
DA - 27.05.2024
KW - Digital Twin
KW - Computed Tomography
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602046
DO - https://doi.org/10.58286/29910
SP - 1
EP - 10
PB - NDT.net
CY - Mayen, Germany
AN - OPUS4-60204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Vogel, Christian
A1 - Kalbe, Ute
T1 - Antimony and vanadium in incineration bottom ash – leaching behavior and conclusions for treatment processes
N2 - Due to its large mineral fraction, incineration bottom ash (IBA) from municipal solid waste incineration is an interesting raw material that can be used for road construction or to produce secondary building materials. However, leaching chloride, sulfate, and potentially harmful heavy metals may cause problems in using IBA in civil engineering. Investigating leaching behavior is crucial for the assessment of the environmental compatibility of IBA applications. Various test procedures are available for that purpose. In the present study, a long-term leaching test of a wet-mechanically treated IBA was performed in a lysimeter for almost six years.
While concentrations of chloride, sulfate and the majority of the heavy metals started to decrease rapidly with progressive liquid-to-solid ratio (L/S), antimony (Sb) and vanadium (V) behaved differently. At the beginning of the lysimeter test, the Sb and V concentrations were low, but after approximately one year of operation at an L/S ratio of around 0.8 L/kg, a steady increase was observed. It was shown that this increase is the result of low Ca concentrations due to the formation of CaCO3.
With the data, the solubility products from Ca-antimonate and Ca-vanadate were calculated. The unusual leaching behavior of Sb and V should be kept in mind when considering field scenarios and evaluating the impact on the environment.
KW - Bottom ash
KW - Lysimeter
KW - Leaching of waste materials
KW - Secondary building materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534317
DO - https://doi.org/10.31025/2611-4135/2021.15115
SN - 2611-4135
VL - 16
SP - 75
EP - 81
PB - CISA
CY - Padua
AN - OPUS4-53431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Kalbe, Ute
T1 - Measurement of the Environmental Impact of Materials
N2 - This Special Issue, ‘Measurement of the Environmental Impact of Materials’, is focused on the impact that materials have on the environmental compartments of soil, water and air. Leaching and emission processes, including underlying mechanisms, are a recurring topic in most published articles in the present Special Issue. Contributions have come from three continents and numerous countries (USA, Germany, France, Latvia, Poland, Russia, Japan, Korea and Thailand) indicating the global dimension of the subject.
KW - Leaching
KW - Recycling
KW - Nano-materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545099
DO - https://doi.org/10.3390/ma15062208
SN - 1996-1944
VL - 15
IS - 6
SP - 1
EP - 3
PB - MDPI
CY - Basel
AN - OPUS4-54509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heisterkamp, I.
A1 - Gartiser, S.
A1 - Schoknecht, Ute
A1 - Happel, O.
A1 - Kalbe, Ute
A1 - Kretzschmar, M.
A1 - Ilvonen, O.
T1 - Investigating the ecotoxicity of construction product eluates as multicomponent mixtures
N2 - The release of hazardous compounds from construction products can harm human health and the environment. To improve the sustainability of construction materials, the leaching of substances from construction products and their potential environmental impact should be assessed. Twenty-seven construction products from different product groups were examined with a combination of standardized leaching tests (dynamic surface leaching test and percolation test) and biotests (algae, daphnia, fish egg, luminescent bacteria, umu and Ames fluctuation tests). To identify the released substances, extensive qualitative and quantitative chemical analyses were performed, including gas chromatographic and liquid chromatographic screening techniques.
Results: Many of the tested eluates caused signifcant ecotoxic efects. Particularly high ecotoxicities were observed for grouts (lowest ineffective dilution (LID) up to 16384) and cork granules (LID up to 24578). The results of ecotoxicity tests allow the prioritization of the eluates that should be subjected to detailed chemical analyses. Organic screening by different methods and ranking the identifed substances based on recorded hazard classification is a suitable approach to identify the relevant toxic substances.
Conclusions: Determining the ecotoxicity of eluates from construction products records the summary effect of all leachable substances. This instrument is especially useful for construction products of complex and largely unknown composition. The ecotoxicological and the chemical–analytical approach complement each other in an ideal way to characterize the potential hazard of eluates from construction products and to identify the environmentally hazardous components in these eluates. Our results confirm that the proposed harmonized methods for testing eluate toxicity are an adequate and applicable procedure to move toward a more sustainable way of building and to reduce toxic effects of construction products in their use phase in the environment.
KW - Construction products
KW - Building materials
KW - Ecotoxicity
KW - Biotests
KW - Leaching
KW - Eluates
KW - Chemical analysis
KW - Analytical screening techniques
KW - Mixture toxicity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568864
DO - https://doi.org/10.1186/s12302-023-00711-w
VL - 35
IS - 1
SP - 1
EP - 20
PB - Springer
AN - OPUS4-56886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roesch, Philipp
A1 - Vogel, Christian
A1 - Wittwer, Philipp
A1 - Huthwelker, T.
A1 - Borca, C.
A1 - Sommerfeld, Thomas
A1 - Kluge, Stephanie
A1 - Piechotta, Christian
A1 - Kalbe, Ute
A1 - Simon, Franz-Georg
T1 - Taking a Look at the Surface: µ-XRF Mapping and Fluorine K-edge µ-XANES Spectroscopy of Organofluorinated Compounds in Environmental Samples and Consumer Products
N2 - For the first time, µ-X-ray fluorescence (µ-XRF) mapping combined with fluorine K-edge µ-X-ray absorption near-edge structure (µ-XANES) spectroscopy was applied to depict per- and polyfluoroalkyl substances (PFAS) contamination and inorganic fluoride in samples concentrations down to 100 µg/kg fluoride. To demonstrate the matrix tolerance of the method, several PFAS contaminated soil and sludge samples as well as selected consumer product samples (textiles, food contact paper and permanent baking sheet) were investigated. µ-XRF mapping allows for a unique element-specific visualisation at the sample surface and enables localisation of fluorine containing compounds to a depth of 1 µm. Manually selected fluorine rich spots were subsequently analysed via fluorine K-edge µ-XANES spectroscopy. To support spectral interpretation with respect to inorganic and organic chemical distribution and compound class determination, linear combination (LC) fitting was applied to all recorded µ-XANES spectra. Complementarily, solvent extracts of all samples were target-analysed via LC-MS/MS spectrometry. The detected PFAS sum values range from 20 to 1136 µg/kg dry weight (dw). All environmentally exposed samples revealed higher concentration of PFAS with a chain length >C8 (e.g. 580 µg/kg dw PFOS for Soil1), whereas the consumer product samples showed a more uniform distribution with regard to chain lengths from C4 to C8. Independent from quantified PFAS amounts via target analysis, µ-XRF mapping combined with µ-XANES spectroscopy was successfully applied to detect both point-specific concentration maxima and evenly distributed surface coatings of fluorinated organic contaminants in the corresponding samples.
KW - PFAS
KW - XRF
KW - LC-MS/MS
KW - XANES
KW - Fluoride
KW - Soil
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576109
DO - https://doi.org/10.1039/D3EM00107E
SN - 2050-7887
SP - 1
EP - 12
PB - Royal Society of Chemistry
AN - OPUS4-57610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Kalbe, Ute
T1 - Case Study on Secondary Building Materials for a Greener Economy
N2 - Half of global material consumption involves mineral material. The circularity is still low so that the enhanced use of secondary building material is required to close loops. Three different secondary building materials are discussed based on exemplary research results: construction and demolition waste (C&D waste), soil-like material, and incineration bottom ash (IBA). Focus was placed on the environmental compatibility of the materials examined mainly by standardized leaching tests. C&D waste was investigated after a wet treatment using a jigging machine, and soil-like material and IBA were characterized with respect to their material composition. Their environmental compatibilities in particular were studied using standard leaching tests (batch tests and column tests).
It was concluded that soil-like material can mostly be utilized even when the precautionary limit values set are exceeded by a factor of less than two. For C&D waste, the fine fraction below 2 mm and the content of brick material is problematic. IBA fulfills quality level “HMVA-2” following German regulations. Improved levels of utilization might be achievable with better treatment technologies.
KW - Incineration bottom ash
KW - Soil-like material
KW - Leaching
KW - Circular economy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576343
DO - https://doi.org/10.3390/app13106010
SN - 2076-3417
VL - 13
IS - 10
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-57634
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Roesch, Philipp
A1 - Wittwer, Philipp
A1 - Sommerfeld, Thomas
A1 - Riedel, Maren
A1 - Leube, Peter
A1 - Kalbe, Ute
A1 - Schoknecht, Ute
A1 - Simon, Franz-Georg
T1 - Per- and Polyfluoroalkyl Substances (PFAS) in Ski Waxes and Snow from Cross-Country Skiing in Germany - Comparative study of Sum Parameter and Target Analysis
N2 - Per- and polyfluoroalkyl substances (PFAS) are often environmentally exposed via discharge through human consumer products, such as ski waxes. In our study we analyzed various ski waxes from the 1980s and 2020s, to determine both the sum parameter values total fluorine (TF), extractable organically bound fluorine (EOF), hydrolysable organically bound fluorine (HOF) as well as targeted PFAS analysis. This showed that modern high-performance waxes contain up to 6 % TF, but also PFAS-free labelled ski waxes contain traces of PFAS with EOF/HOF values in the low mg kg-1 range. With the ban of all fluorine-based waxes with the start of the 2023/2024 winter season this will probably change soon. Moreover, we applied our analysis methods to snow samples from a frequently used cross country ski trail (Kammloipe) in the Ore Mountain region in Germany, assessing the potential PFAS entry/discharge through ski waxes. Melted snow samples from different spots were analyzed by the adsorbable organically bound fluorine (AOF) sum parameter and PFAS target analysis and confirmed the abrasion of the ski waxes into the snow. Moreover, on a PFAS hotspot also soil samples were analyzed, which indicate that PFAS from the ski waxes adsorb after snow melting into the soil.
KW - Combustion Ion Chromatography
KW - Per- and Polyfluoroalkyl substances (PFAS)
KW - Consumer Products
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612760
DO - https://doi.org/10.1016/j.hazadv.2024.100484
VL - 16
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-61276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Kalbe, Ute
A1 - Heisterkamp, I.
A1 - Kretzschmar, M.
A1 - Gartiser, S.
A1 - Happel, O.
A1 - Ilvonen, O.
T1 - Release of substances from joint grouts based on various binder types and their ecotoxic effects
N2 - Background: The leaching of substances and the ecotoxic effects of eluates were studied for joint grouts that are based on various types of binders. Eight products, two of them containing either epoxy resin, polybutadiene or polyurethane binders, or modifed cement, were investigated using harmonized leaching tests for construction products in combination with ecotoxicity tests on algae, daphnia, luminescent bacteria, fish eggs and mutagenicity in accordance with CEN/TR 17105. In addition to basic parameters, such as pH, TOC, and inorganic components, organic substances in the eluates were analysed by gas and liquid chromatography in combination with mass spectrometry. Quantitative analyses in combination with ecotoxicity data on selected substances were used to deduce which substances cause the observed ecotoxic effects.
Results: Different patterns of ecotoxic effects were observed in joint grouts with different binder types. The most ecotoxic effects were observed in epoxy resin-based products, followed by polybutadiene-based products. Fewer ecotoxic effects were observed in polyurethane-based products and modifed cements. Some of these showed no ecotoxicity. Some of the substances in the eluates were identified and related to ecotoxic effects. 4-Tert-butylphenol and amines probably contributed to the ecotoxic effects of at least one of the epoxy resin-based renders, whereas cobalt is assumed to contribute to the toxic effect on algae of one of the polybutadiene-based products. However, only some of the leached substances could be identifed, and only some of the ecotoxic effects can be explained by the available information on the composition of eluates and known ecotoxic profiles of the identified substances.
Conclusions: Ecotoxicity tests on eluates from leaching tests indicate whether environmentally hazardous substances can be leached from construction products. Combined ecotoxicity tests and chemical analysis of eluates from EU-wide harmonized leaching tests for construction products can provide information on substances that cause these effects. This supports the identifcation and development of environmentally friendly construction products.
This study confirmed that ecotoxicity tests in accordance with CEN/TR 17105 are a tool well-suited to support the implementation of the European Commission’s zero pollution vision for 2050 and to reduce pollution to levels no longer considered harmful to health and natural ecosystems.
KW - Joint grouts
KW - Leaching
KW - Ecotoxixity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562392
DO - https://doi.org/10.1186/s12302-022-00686-0
SN - 2190-4707
VL - 34
IS - 1
SP - 1
EP - 16
PB - Springer Nature
CY - Berlin
AN - OPUS4-56239
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pienkoß, Fabian
A1 - Kalbe, Ute
A1 - Simon, Franz-Georg
T1 - Nassmechanische Aufbereitung von Bauschutt‐Brechsand mit der Setztechnik – ein Schritt auf dem Weg zum Ersatzbaustoff
T1 - Wet-Mechanical Processing of Crushed-Sand from Construction-Waste - A First Step Towards a Circular Building Material
N2 - Das Recycling von gemischten Baustoffen führt neben der Herstellung von Gesteinskörnungen parallel zu einem stärker schadstoffbelasteten Stoffstrom, der circa ein Drittel der ursprünglichen Masse ausmacht. Dieser sogenannte Brechsand endet derzeit in der Deponierung und wird somit der Kreislaufwirtschaft entzogen. Der vorliegende Beitrag untersucht nun die Aufbereitung dieses Materials unter Verwendung einer Setzmaschine im Pilotmaßstab. Hierbei wird die Eignung dieser Technik evaluiert und das Aufbereitungsprodukt als möglicher Ersatzbaustoff untersucht.
N2 - Besides the generation of aggregates, recycling of mixed construction and demolition waste leads to a more polluted side stream accounting for up to one third of the input materials. This so-called crushed sand often ends up in landfills and is hence lost for a circular economy. This article reports about the processing of this material using a pilot plant jig. The suitability of jigging technology is evaluated, and the product is analyzed as possible circular building material.
KW - Aufbereitung
KW - Ersatzbaustoff
KW - Kreislaufwirtschaft
KW - Setzmaschine
KW - Umweltverträglichkeit
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585978
DO - https://doi.org/10.1002/cite.202300019
SN - 0009-286X
VL - 95
IS - 12
SP - 1916
EP - 1924
PB - Wiley VHC-Verlag
AN - OPUS4-58597
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roesch, Philipp
A1 - Schinnen, Andrea
A1 - Riedel, Maren
A1 - Sommerfeld, Thomas
A1 - Sawal, G.
A1 - Bandow, N.
A1 - Vogel, Christian
A1 - Kalbe, Ute
A1 - Simon, Franz-Georg
T1 - Investigation of pH-dependent extraction methods for PFAS in (fluoropolymer-based) consumer products: A comparative study between targeted and sum parameter analysis
N2 - Here, we report a comparative study of different sum parameter analysis methods for the extraction of per- and polyfluoroalkyl substances (PFAS) from manufactured consumer products, which can be measured by combustion ion chromatography (CIC). Therefore, a hydrolysis-based extraction method was further developed, which accounts for the addition of hydrolyzable covalently bound polyfluoroalkylated side-chain polymers (SFPs) to the extractable organic fluorine portion of the mass balance proposed as "hydrolyzable organically bound fluorine" (HOF). To test this hypothesis, the method was applied to 39 different consumer products containing fluoropolymers or monomeric PFAS taken from four different categories: outdoor textiles, paper packaging, carpeting, and permanent baking sheets. We also evaluated the method's efficiency by extracting four synthesized fluorotelomer polyacrylate reference compounds. The total fluorine (TF) and extractable organically bound fluorine (EOF) values were measured through CIC using established protocols. The TF values ranged from sub-ppb to %-levels, depending on the compound class. All samples showed results for hydrolyzed organofluorine (HOF) between 0.03 and 76.3 μg/g, while most EOF values were lower ( 250 °C into an anhydrous, amorphous intermediate Fe3(PO4)2 phase, yet the bulk shape and morphology of the starting vivianite crystals were retained. This amorphous intermediate phase remained stable until T > 500 °C, after which a redox-dependent crystallization into two different minerals was observed. Under anoxic conditions, the amorphous ferrous intermediate (Fe3(PO4)2) transformed into the crystalline ferrous phosphate (graftonite, (Fe2+)3(PO4)2), while under oxic conditions it crystallized into a ferric phosphate (rodolicoite, Fe3+PO4). Graftonite formation occurs via an exothermic molar enthalpy (ΔHcryst) of −16.7 ± 0.2 kJ mol−1. Rietveld refinements of the two crystalline endmembers (vivianite and graftonite) revealed a unit cell volume decrease of ∼3.1% during the transformation, which was observed by in situ electron microscopic observations as an overall shrinking of the initial vivianite crystals. Despite volume loss and bubble-like features, the original vivianite shape was preserved, indicating a solid-state pseudomorphic transformation. Ex situ XRD and TEM-EELS analyses confirmed the ferrous-to-ferric oxidation, forming rodolicoite, through changes in the Fe geometry and oxidation state.
KW - Vivianite
KW - Graftonite
KW - Crystallization enthalpy
KW - Ferrous phosphates
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640782
DO - https://doi.org/10.1021/acs.inorgchem.5c02399
SN - 0020-1669
VL - 46
IS - 36
SP - 18227
EP - 18236
PB - American Chemical Society (ACS)
AN - OPUS4-64078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Tobias
A1 - Gornushkin, Igor B.
T1 - Mass and mole fractions in calibration-free LIBS
N2 - This technical note highlights the fact that CF-LIBS algorithms work in mole fractions, while results of spectrochemical analysis are usually reported in mass fractions or mass percent. Ignoring this difference and not converting mole fractions to mass fractions can lead to errors in reported concentrations determined by the CF-LIBS method and inadequate comparison of these concentrations with certified concentrations. Here, the key points of the CF-LIBS algorithm are reproduced and the formulae for converting a mole fraction to a mass fraction and vice versa are given. Several numerical examples are also given, which show that the greater the difference between the molar mass of an individual element in a sample and the average molar mass, the greater the discrepancy between the mole and mass fractions.
KW - Spectroscopy
KW - Analytical Chemistry
KW - LIBS
KW - Calibration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598611
DO - https://doi.org/10.1039/d4ja00028e
SN - 0267-9477
VL - 39
IS - 4
SP - 1030
EP - 1032
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Niederleithinger, Ernst
A1 - Wang, Xin
A1 - Herbrand, M.
A1 - Müller, M.
T1 - Processing ultrasonic data by coda wave interferometry to monitor load tests of concrete beams
N2 - Ultrasonic transmission measurements have been used for decades to monitor concrete elements, mostly on a laboratory scale. Recently, coda wave interferometry (CWI), a technique adapted from seismology, was introduced to civil engineering experiments. It can be used to reveal subtle changes in concrete laboratory samples and even large structural elements without having a transducer directly at the place where the change is taking place. Here, several load tests until failure on large posttensioned concrete beams have been monitored using networks of embedded transducers. To detect subtle effects at the beginning of the experiments and cope with severe changes due to cracking close to failure, the coda wave interferometry procedures had to be modified to an adapted step-wise approach. Using this methodology, we were able to monitor stress distribution and localize large cracks by a relatively simple technique. Implementation of this approach on selected real structures might help to make decisions in infrastructure asset management.
KW - Ultrasound
KW - Concrete
KW - Monitoring
KW - Coda wave interferometry
KW - Embedded transducers
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452328
DO - https://doi.org/10.3390/s19010147
SN - 1424-8220
VL - 19
IS - 1
SP - Article 147, 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-45232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Niederleithinger, Ernst
A1 - Herbrand, Martin
A1 - Müller, Matthias
T1 - Codawelleninterferometrie zur Detektion von Spannungszuständen in Betonbauteilen
N2 - Informationen zu in Betonbauteilen stattfindenden Umlagerungsprozessen sowie Druckspannungsverteilungen können mit konventioneller Messtechnik bislang nicht zweifelsfrei beantwortet werden. Ultraschallmessungen mit eingebetteten Sensoren könnten hier eine sinnvolle Ergänzung zur konventionellen Messtechnik sein. Durch Einsatz der Codawelleninterferometrie (CWI) sind hiermit schon sehr kleine Änderungen im Material detektierbar.
Um diese neue Methodik zu evaluieren, wurde das Forschungsprojekt „Querkrafttragfähigkeit von Spannbetonbrücken – Erfassung von Spannungszuständen in den Spannbetonversuchsträgern mit Ultraschallsensoren“ durch die Bundesanstalt für Straßenwesen (BASt) initiiert. In diesem Projekt wurden durch die Bundesanstalt für Materialforschung und –prüfung (BAM) Ultraschall-Transducer in mehrere Spannbetonträger des Instituts für Massivbau der RWTH Aachen eingebettet, die anschließend bis zum Bruch belastet wurden.
Der Belastungsversuch an einem der Spannbetondurchlaufträger zeigte das große Potential dieser Methodik. Die im Netzwerk erfassten Änderungen der Ultraschallwellengeschwindigkeit geben die Spannungsverhältnisse im Längsschnitt des Trägers schon bei sehr niedrigen Belastungen qualitativ richtig wieder und zeigen bei hohen Belastungen eine gute Korrelation zum Rissbild. Dabei weisen räumliche Anomalien und Änderungen in der Charakteristik der Geschwindigkeitsänderungen oft schon auf Rissbildung hin, wenn diese noch nicht an der Oberfläche sichtbar ist. Dies zeigt das Potential im Hinblick auf eine Frühwarnung. Hierfür und ebenso in Bezug auf eine Quantifizierung der Effekte ist aber noch Entwicklungsarbeit notwendig. Ein Vorteil der Methodik ist, dass die Transducer nicht direkt am Ort der Änderung platziert werden müssen und einen relativ großen Bereich um die Transducer herum erfassen.
T2 - DGZfP Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Ultraschall
KW - Monitoring
KW - Codawelleninterferometrie
KW - Brückenträger
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448642
SP - Mo.3.A.4, 1
EP - 8
PB - DGZfP
AN - OPUS4-44864
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Coelho Lima, Isabela
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
T1 - Advanced ultrasonic imaging for concrete: Alternative imaging conditions for reverse time migration
N2 - Ultrasound echo is a widely used NDT technique for determining the internal geometry of structures. Reverse-time migration (RTM) has been recently introduced to NDT applications, as an imaging method for ultrasound data, to overcome some of the limitations (e.g. imaging steeply dipping reflector) experienced by the Synthetic Aperture Focusing Technique (SAFT), the most commonly used imaging algorithm for these measurements.
The standard implementation of RTM also experiences some drawbacks caused by its imaging condition, which is based on the zero-lag of the cross-correlation between source and receiver wavefields and generates high-amplitude low-frequency artifacts. Three alternative imaging conditions, developed for seismic data applications, were tested for their ability to provide better images than the standard cross-correlation: illumination compensation, deconvolution and wavefield decomposition. A polyamide specimen was chosen for the simulation of a synthetic experiment and for real data acquisition. The migrations of both synthetic and real data were performed with the software Madagascar. The illumination imaging condition was able to reduce the low-frequency noise and had a good performance in terms of computing time. The deconvolution improved the resolution in the synthetic tests, but did not showed such benefit for the real experiments. Finally, as for the wavefield decomposition, although it presented some advantages in terms of attenuating the low-frequency noise and some unwanted reflections, it was not able to image the internal structure of the polyamide as well as the cross-correlation did. Suggestions on how to improve the cost-effectiveness of the implementation of the deconvolution and wavefield decomposition were presented, as well as possible investigations that could be carried out in the future, in order to obtain better results with those two imaging conditions.
T2 - DGZfP Jahrestagung 2018
CY - Leipzig
DA - 07.05.2018
KW - Ultrasound
KW - Reverse time migration
KW - Imaging condition
KW - Concrete
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448704
SP - Mi.3.A.4, 1
EP - 10
PB - DGZfP
AN - OPUS4-44870
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Niederleithinger, Ernst
A1 - Wiggenhauser, Herbert
A1 - Milmann, Boris
T1 - LAUS - Erste praktische Erfahrungen mit einem neuartigen Ultraschallsystem großer Eindringtiefe
N2 - Konventionelle Systeme zur Ultraschall-Echo-Prüfung von Betonbauteilen sind in ihrer Eindringtiefe auf etwa einem Meter begrenzt. Zur Prüfung stärkerer Objekte war die Entwicklung eines neuartigen Prüfsystems notwendig. Das LAUS-System (Large Aperture UltraSound) besteht aus 12 einzelnen Arrays, die mit jeweils 32 Einzelprüfköpfen (Scherwellen, 25 – 50 kHz) als Sender oder Empfänger betrieben werden können. Sie werden unabhängig auf Betonoberflächen mit Unterdruck befestigt und kommunizieren drahtlos untereinander und mit der Zentraleinheit. Alle möglichen Kombinationen ergeben 132 Einzelmessungen, die zur Rekonstruktion des durchschallten Volumens genutzt werden. Mehrere dieser Datensätze lassen sich zu einer 3D-Auswertung kombinieren. Das System wurde an mehreren Testobjekten und Bauwerken erfolgreich erprobt. So konnte die fünf Meter dicke, sehr stark bewehrte Fundamentplatte des Fallturms auf dem BAM-Testgelände bei Horstwalde durchschallt werden. Ein zweites Beispiel ist die erfolgreiche Detektion von Spannkanälen in 1,8 m Tiefe in einem massiven Brückenbauwerk.
T2 - Fachtagung Bauwerksdiagnose 2018
CY - Berlin
DA - 15.2.2018
KW - Beton
KW - Ultraschall
KW - LAUS
KW - Brücke
KW - Fundament
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-445786
UR - https://www.bauwerksdiagnose2018.de/Portals/bauwerksdiagnose2018/BB/16.pdf
SP - Paper 16, 1
EP - 8
CY - Berlin
AN - OPUS4-44578
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abraham, O.
A1 - Ferria, H.
A1 - Niederleithinger, Ernst
A1 - Brühwiler, E.
A1 - Dalsgard Sörensen, J.
A1 - Klikowicz, P.
A1 - Kirsch, F.
A1 - Niedermayer, H.
A1 - Yalamas, T.
T1 - INFRASTAR - Innovation and networking for fatigue and reliability analysis of structures - Training for assessment of risk - H2020
N2 - "INFRASTAR aims to develop knowledge, expertise and skills for optimal and reliable management of structures. The generic methodology is applied to bridges and wind turbines in relation to fatigue offering the opportunity to deal with complementary notions (such as old and new asset management, unique and similar structures, wind and traffic actions) while addressing 3 major challenges: 1/ advanced modelling of concrete fatigue behaviour, 2/new non destructive testing methods for early aged damage detection and 3/probabilistic approach of structure reliability under fatigue. Benefit of cross-experience and inter-disciplinary synergies creates new knowledge. INFRASTAR proposes innovative solutions for civil infrastructure asset management so that young scientists acquire a high employment profile in close dialogue between industry and academic partners. Modern engineering methods, including probabilistic approaches, risk and reliability assessment tools, will take into account the effective structural behaviour of existing bridges and wind turbines by exploiting monitored data. Existing methods and current state-of -the art is based on excessive conservatism which produces high costs and hinders sustainability. INFRASTAR improves knowledge for optimising the design of new structures, for more realistic verification of structural safety and more accurate prediction of future lifetime of the existing structures. That is a challenge for a sustainable development because it reduces building material and energy consumption as well as CO2 production. Within the global framework of optimal infrastructure asset management, INFRASTAR will result in a multi-disciplinary body of knowledge covering generic problems from the design stage process of the new civil infrastructures up to recycling after dismantlement. This approach and the proposed methods and tools are new and allow a step forward for innovative and effective process."
KW - Concrete
KW - Fatigue
KW - Wind turbine
KW - Bridge
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447016
UR - http://www.ingentaconnect.com/content/sil/impact/2018/00002018/00000001/art00023
DO - https://doi.org/10.21820/23987073.2018.70
SN - 2398-7073
VL - 2018
IS - 1
SP - 70
EP - 72
PB - Science Impact Ltd.
CY - Bristol, UK
AN - OPUS4-44701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kirilina, E.
A1 - Helbling, S.
A1 - Morawski, M.
A1 - Pine, K.
A1 - Reimann, K.
A1 - Jankuhn, S.
A1 - Dinse, J.
A1 - Deistung, A.
A1 - Reichenbach, J. R.
A1 - Trampel, R.
A1 - Geyer, S.
A1 - Müller, Larissa
A1 - Jakubowski, Norbert
A1 - Arendt, T.
A1 - Bazin, P.-L.
A1 - Weiskopf, N.
T1 - Superficial white matter imaging: Contrast mechanisms and whole-brain in vivo mapping
N2 - Superficial white matter (SWM) contains the most cortico-cortical white matter connections in the human brain encompassing the short U-shaped association fibers. Despite its importance for brain connectivity, very little is known about SWM in humans, mainly due to the lack of noninvasive imaging methods. Here, we lay the groundwork for systematic in vivo SWM mapping using ultrahigh resolution 7 T magnetic resonance imaging. Using biophysical modeling informed by quantitative ion beam microscopy on postmortem brain tissue, we demonstrate that MR contrast in SWM is driven by iron and can be linked to the microscopic iron distribution. Higher SWM iron concentrations were observed in U-fiber–rich frontal, temporal, and parietal areas, potentially reflecting high fiber density or late myelination in these areas. Our SWM mapping approach provides the foundation for systematic studies of interindividual differences, plasticity, and pathologies of this crucial structure for cortico-cortical connectivity in humans.
KW - Magnetic resonance imaging
KW - Laser ablation
KW - ICP-MS
KW - Brain
KW - Imaging
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514430
DO - https://doi.org/10.1126/sciadv.aaz9281
SN - 2375-2548
VL - 6
IS - 41
SP - eaaz9281
PB - American Association for the Advancement of Science (Science/AAAS)
CY - Washington, DC, USA
AN - OPUS4-51443
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chakraborty, J.
A1 - Wang, Xin
A1 - Stolinski, M.
T1 - Damage Detection in Multiple RC Structures Based on Embedded Ultrasonic Sensors and Wavelet Transform
N2 - This paper summarizes the results of research aimed at assessing cracks in reinforced concrete structures using embedded ultrasonic sensors. The diffuse ultrasonic waves were considered to evaluate the health status of the tested structures. There are different algorithms used to detect cracks in the structure, but most studies have been performed on benchmark reinforced concrete (RC) structures and in laboratory conditions. Since there were difficulties with the validity of Damage detection in real structures in the presence of environmental changes and noises, the application of advanced signal processing methods was necessary. Therefore, the wavelet transform was applied to process ultrasonic signals acquired from multiple civil structures. It is shown that the ultrasonic sensors with an applied wavelet transform algorithm on collected signals can successfully detect cracks in the laboratory as well as in a real environment. Experimental results showed a perfect match for detecting damage and quasi-static load in the presence of environmental changes. The results were confirmed with other techniques. In addition, designing an extra filter for removing noises can be avoided by using the applied algorithms. The obtained results confirmed that diffuse ultrasonic sensor methodology with the proposed algorithm is useful and effective in Monitoring real RC structures, and it is better than traditional techniques.
KW - Ultrasound
KW - Damage
KW - Detection
KW - Concrete
KW - Wavelet
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523089
DO - https://doi.org/10.3390/buildings11020056
VL - 11
IS - 2
SP - 56
PB - MDPI
AN - OPUS4-52308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Effner, Ute
A1 - Mielentz, Frank
A1 - Niederleithinger, Ernst
A1 - Friedrich, C.
A1 - Mauke, R.
A1 - Mayer, K.
T1 - Prüfung von Abdichtbauwerken für Endlager auf Risse – eine Herausforderung
N2 - Im Jahr 2011 hat der Bundestag in Deutschland den Ausstieg aus der Kernenergie beschlossen. Der angefallene Abfall wird mehr als hunderttausend Jahre eine derartig hohe Aktivität besitzen, dass er eine erhebliche Gefahr für nachfolgende Generationen darstellen kann. Dieser radioaktive Abfall soll in tiefen geologischen Formationen (z.B. Salz, Ton oder Kristallin) sicher endgelagert werden. Die Endlager werden mittels sogenannter geotechnischer Abdichtbauwerke (Schachtbzw. Streckenverschlüsse) verschlossen, wofür u.a. Zement- oder Sorel-basierte Baustoffe (Betone) in Frage kommen. Die Beschreibung des Dichtvermögens dieser Bauwerke ist unabdingbar. In der Forschungsphase werden verschiedene Werkstoffe untersucht und Methoden für die zerstörungsfreie Untersuchung der Bauwerke als Mittel der Qualitätsprüfung entwickelt. Hierbei ist der Nachweis der Rissfreiheit bzw. die Detektion möglicher Risse ein vorrangiges Thema. In den letzten Jahren konnten bereits umfangreiche Erfahrungen mit der Untersuchung von in-situ-Versuchsobjekten in Realmaßstab gesammelt werden. Die Messungen wurden im Endlager für radioaktive Abfälle Morsleben am in-situ-Versuch “Abdichtbauwerk im Steinsalz” und in der Grube Teutschenthal am Großversuch GV2 durchgeführt. Es ist gelungen mit einem neu entwickelten Ultraschall-Messsystem Eindringtiefen bis ca. 9,0 m zu realisieren. Die Messungen mit dem Large Aperture Ultrasonic System in Kombination mit der Rekonstruktion-Methode Synthetic Aperture Focusing Technique zeigen, dass die zerstörungsfreie Prüfung von Abdichtbauwerken möglich und die Nutzung des Messsystems zur Qualitätssicherung bei der Erstellung der Verschlussbauwerke vielversprechend ist.
N2 - In 2011, the German Bundestag decided to phase out nuclear energy. The resulting waste will remain highly radioactive for many hundreds of thousands of years and represents a considerable danger for future generations. This radioactive waste is to be safely disposed of in deep geological formations (e.g. salt, clay or crystalline). The repositories will be sealed by means of engineered barrier systems. The impermeability of these structures is indispensable.
In the current research phase, various materials are being investigated and methods for monitoring the structures are being developed. In this context, the investigation of cracks is a priority topic.
In recent years, BAM has gained extensive experience in the investigation of in-situ test objects in full scale. The measurements were performed in the Morsleben repository for radioactive waste at the test structure for the in-situ experiment "Sealing structure in rock salt" and in the Teutschenthal mine at the large-scale GV2 test structure.
With a newly developed ultrasonic measuring system it has been possible to achieve penetration depths of up to approx. 9.0 m. Measurements with the Large Aperture Ultrasonic System in combination with the Synthetic Aperture Focusing Technique reconstruction method show that the non-destructive testing of sealing structures is possible and the use of the measuring system for quality assurance in the construction of sealing structures is promising.
KW - Abdichtbauwerk / Verschlussbauwerk
KW - Zerstörungsfreie Prüfung
KW - Large Aperture Ultrasonic System
KW - Synthetic Aperture Focusing Technique
KW - Ultraschall-Echo-Verfahren
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520298
DO - https://doi.org/10.1002/mawe.202000118
SN - 1521-4052
VL - 52
IS - 1
SP - 19
EP - 31
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-52029
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Niederleithinger, Ernst
A1 - Wang, Xin
A1 - Mierschke, Vivien
A1 - Bertschat, Anja Sophie
T1 - Concepts from seismic interferometry transferred to sonic and ultrasonic concrete inspection and monitoring
N2 - Seismic interferometry (SI) deals either with the sensible detection of changes in the subsurface or with the reconstruction of virtual signals between two receivers by crosscorrelation of signals from diffuse sources. These concepts can be applied in NDT in civil engineering for various purposes, e. g. to detect changes in bridges. Here it is demonstrated using data from a reference structure on our test site. Practical applications can be expected in the very near future.
T2 - 12th European Conference on Non-Destructive Testing (ECNDT 2018)
CY - Gothenburg, Sweden
DA - 11.6.2018
KW - Ultrasound
KW - Concrete
KW - Monitoring
KW - Coda
KW - Interferometry
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468465
UR - http://www.ndt.net/?id=22760
SN - 1435-4934
VL - 23
IS - 8
SP - 1
EP - 2
PB - NDT.net
CY - Kirchwald
AN - OPUS4-46846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Clauß, F.
A1 - Epple, Niklas
A1 - Ahrens, M. A.
A1 - Niederleithinger, Ernst
A1 - Mark, P.
T1 - Comparison of Experimentally Determined Two-Dimensional Strain Fields and Mapped Ultrasonic Data Processed by Coda Wave Interferometry
N2 - Due to the high sensitivity of coda waves to the smallest structural alterations such as strain, humidity or temperature changes, ultrasonic waves are a valid means to examine entire structures employing networks of ultrasonic transducers. In order to substantiate this ex ante assessment, the viability of measuring ultrasonic waves as a valid point of reference and inference for structural changes is to be further scrutinized in this work. In order to investigate the influence of mechanical strain on ultrasonic signals, a four-point bending test was carried out on a reinforced concrete beam at Ruhr University Bochum. Thus, measurements collected from a network of selected transducer pairings arranged across the central, shear-free segment of the test specimen, were correlated to their respective strain fields. Detected ultrasonic signals were evaluated employing Coda Wave Interferometry. Such analysis comprised the initial non-cracked state as well as later stages with incremental crack depth and quantity. It was to ascertain that the test specimen can in fact be qualitatively compartmentalized into areas of compression and tension identified via Relative Velocity Changes presented in Attribute Maps. However, since results did not entail a zero crossing, i.e., neither positive nor negative values were to be calculated, only relative changes in this work displayed staggered over the height of the object under test, are discussed. Under the given methodological premises, additional information is currently required to make quantitative assertions regarding this correlation of ultrasonic and strain results. This holds true for the comparability of the ultrasonic and strain results for both non-cracked and even the cracked state.
KW - Digital image correlation
KW - Fiber optic sensors
KW - Coda Wave Interferometry
KW - Ultrasound
KW - Concrete
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510501
DO - https://doi.org/10.3390/s20144023
SN - 1424-8220
VL - 20
IS - 14
SP - Paper 4023, 1
PB - MDPI
CY - Basel
AN - OPUS4-51050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Xin
A1 - Chakraborty, J.
A1 - Bassil, A.
A1 - Niederleithinger, Ernst
T1 - Detection of Multiple Cracks in Four-Point Bending Tests Using the Coda Wave Interferometry Method
N2 - The enlargement of the cracks outside the permitted dimension is one of the main causes for the reduction of service life of Reinforced Concrete (RC) structures. Cracks can develop due to many causes such as dynamic or static load. When tensile stress exceeds the tensile strength of RC, cracks appear. Traditional techniques have limitations in early stage damage detection and localisation, especially on large-scale structures. The ultrasonic Coda Wave Interferometry (CWI) method using diffuse waves is one of the most promising methods to detect subtle changes in heterogeneous materials, such as concrete. In this paper, the assessment of the CWI method applied for multiple cracks opening detection on two specimens based on four-point bending test is presented. Both beams were monitored using a limited number of embedded Ultrasonic (US) transducers as well as other transducers and techniques (e.g., Digital Image Correlation (DIC), LVDT sensors, strain gauges, and Fiber Optics Sensor (FOS)). Results show that strain change and crack formation are successfully and efficiently detected by CWI method even earlier than by the other techniques. The CWI technique using embedded US transducers is undoubtedly a feasible, efficient, and promising method for long-term monitoring on real infrastructure.
KW - Coda wave interferometry
KW - Reinforced concrete
KW - Cracks
KW - SHM
KW - Damage detection
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506666
DO - https://doi.org/10.3390/s20071986
VL - 20
IS - 7
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-50666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Niederleithinger, Ernst
A1 - Gardner, S.
A1 - Kind, Thomas
A1 - Kaiser, R.
A1 - Grunwald, Marcel
A1 - Yang, G.
A1 - Redmer, Bernhard
A1 - Waske, Anja
A1 - Mielentz, Frank
A1 - Effner, Ute
A1 - Köpp, Christian
A1 - Clarkson, A.
A1 - Thompson, F.
A1 - Ryan, M.
A1 - Mahon, D.
T1 - Muon Tomography of the Interior of a Reinforced Concrete Block: First Experimental Proof of Concept
N2 - Quality assurance and condition assessment of concrete structures is an important topic world-wide due to the aging infrastructure and increasing traffic demands. Common topics include, but are not limited to, localisation of rebar or tendon ducts, geometrical irregularities, cracks, voids, honeycombing or other flaws. Non-destructive techniques such as ultrasound or radar have found regular, successful practical application but sometimes suffer from limited resolution and accuracy, imaging artefacts or restrictions in detecting certain features. Until the 1980s X-ray transmission was used in case of special demands and showed a much better resolution than other NDT techniques. However, due to safety concerns and cost issues, this method is almost never used anymore. Muon tomography has received much attention recently. Novel detectors for cosmic muons and tomographic imaging algorithms have opened up new fields of application, such as the investigation of freight containers. Muon imaging also has the potential to fill some of the gaps currently existing in concrete NDT. As a first step towards practical use and as a proof of concept we used an existing system to image the interior of a reference reinforced 600 kg concrete block. Even with a yet not optimized setup for this kind of investigation, the muon imaging results are at least of similar quality compared to ultrasonic and radar imaging, potentially even better. The data acquisition takes more time and signals contain more noise, but the images allowed to detect the same important features that are visible in conventional high energy X-ray tomography. In our experiment, we have shown that muon imaging has potential for concrete inspection. The next steps include the development of mobile detectors and optimising acquisition and imaging parameters.
KW - Concrete
KW - Muon
KW - Radar
KW - Ultrasound
KW - X-ray
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529974
DO - https://doi.org/10.1007/s10921-021-00797-3
VL - 40
IS - 3
SP - 1
EP - 14
PB - Springer Nature
AN - OPUS4-52997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Xin
A1 - Niederleithinger, Ernst
A1 - Hindersmann, Iris
T1 - The installation of embedded ultrasonic transducers inside a bridge to monitor temperature and load influence using coda wave interferometry technique
N2 - This article presents a unique method of installing a special type of embedded ultrasonic transducers inside a 36-m-long section of an old bridge in Germany. A small-scale load test was carried out by a 16 ton truck to study the temperature and load influence on the bridge, as well as the performance of the embedded transducers. Ultrasonic coda wave interferometry technique, which has high sensitivity in detecting subtle changes in a heterogeneous medium, was used for the data evaluation and interpretation. The separation of two main influence factors (load effect and temperature variation) is studied, and future applications of wave velocity variation rate Φ for structural health condition estimation are discussed. As a preliminary research stage, the installation method and the performance of the ultrasonic transducer are recognized. Load- and temperature-induced weak wave velocity variations are successfully detected with a high resolution of 10−4%. The feasibility of the whole system for long-term structural health monitoring is considered, and further research is planned.
KW - Ultrasound
KW - Bridge
KW - Monitoring
KW - coda wave interferometry
KW - embedded
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527978
DO - https://doi.org/10.1177/14759217211014430
SN - 1475-9217
VL - 21
IS - 3
SP - 913
EP - 927
PB - SAGE
AN - OPUS4-52797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mielentz, Frank
A1 - Stolpe, Heiko
A1 - Effner, Ute
A1 - Behrens, Matthias
A1 - Bernstein, Thomas
A1 - Niederleithinger, Ernst
T1 - Entwicklung einer Bohrlochsonde für Ultraschalluntersuchungen an Abschlussbauwerken in Endlagern
N2 - Für die Qualitätssicherung von Abschlusswerken für Endlager wird eine Ultraschall-Bohrlochsonde entwickelt. Mithilfe dieser Sonde, die aus einer Vielzahl von einzelnen koppelmittelfreien Ultraschall-Punktkontaktprüfköpfen besteht, soll die Rissfreiheit der Versuchsbauwerke überprüft werden.
Ein erster Prototyp der Sonde wurde mit einem kommerziellen Ultraschallgerät betrieben und bestand aus 12 Transversalwellen-Punktkontaktprüfköpfen von denen jeweils sechs als Sender und sechs als Empfänger parallelgeschaltet waren. Um den erzeugten Schalldruck der Bohrlochsonde zu steigern, wurde bei der Neuentwicklung die Prüfkopfanzahl erhöht und zusätzlich die laufzeitgesteuerte Anregung der einzelnen Prüfköpfe vorgesehen. Für die Anregung der Prüfköpfe mit programmierten Zeitverzögerungen wurde ein neuartiger mehrkanaliger Sender für bipolare Rechtecksignale entwickelt.
Durch die Entwicklung der Bohrlochsonde soll eine dynamische Anpassung der Prüfkopf-Apertur sowie eine Fokussierung des Schallfeldes in Abhängigkeit der zu untersuchenden Tiefe erfolgen. Mithilfe entsprechender Anregungsfunktionen kann das Schallfeld der Bohrlochsonde unterschiedlich geformt werden, z. B. ist auch ein Schwenken des fokussierten Schallbündels möglich. Dadurch wird das erfasste Prüfvolumen begrenzt und auf diese Weise das Signal-Störverhältnis der Empfangssignale verbessert. In Kombination mit SAFT-Rekonstruktionsrechnungen wird durch eine optimierte Abstrahlcharakteristik der Sonde mit einem hohen Schalldruck unter verschiedenen Winkeln eine verbesserte Signalqualität und damit eine erhöhte Aussagesicherheit der Ergebnisse in der Objektabbildung erwartet.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Abdichtbauwerk
KW - Bohrlochsonde
KW - Ultraschall-Echoverfahren
KW - Verschlussbauwerk
KW - Zerstörungsfreie Prüfung
KW - Ultraschall-Messtechnik
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526746
UR - https://jahrestagung.dgzfp.de/portals/jt2021/bb176/inhalt/poster.htm
SN - 978-3-947971-18-3
VL - 176
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-52674
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Büttner, C.
A1 - Niederleithinger, Ernst
A1 - Buske, S.
A1 - Friedrich, C.
T1 - Ultrasonic Echo Localization Using Seismic Migration Techniques in Engineered Barriers for NuclearWaste Storage
N2 - In the framework of non-destructive-testing advanced seismic imaging techniques have been applied to ultrasonic echo data in order to examine the integrity of an engineered test-barrier designed to be used for sealing an underground nuclear waste disposal site. Synthetic data as well as real multi-receiver ultrasonic data acquired at the test site were processed and imaged using Kirchhoff prestack depth migration reverse time migration (RTM). In general, both methods provide a good Image quality as demonstrated by various case studies, however deeper parts within the test barrier containing inclined reflectors were reconstructed more accurately by RTM. In particular, the image quality of a specific target reflector at a depth of 8 m in the test-barrier has been significantly improved compared to previous investigations using synthetic aperture Focusing technique, which justifies the considerable computing time of this method.
KW - Radioactive waste disposal
KW - Engineered barrier
KW - Ultrasound
KW - Imaging
KW - Crack detection
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537956
DO - https://doi.org/10.1007/s10921-021-00824-3
SN - 0195-9298
VL - 40
IS - 4
SP - 1
EP - 10
PB - Springer
AN - OPUS4-53795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, T.
A1 - Sens-Schönfelder, C.
A1 - Epple, Niklas
A1 - Niederleithinger, Ernst
T1 - Imaging of Small-Scale Heterogeneity and Absorption Using Adjoint Envelope Tomography: Results From Laboratory Experiments
N2 - To complement the information provided by deterministic seismic imaging at length scales above a certain resolution limit we present the first application of adjoint envelope tomography (AET) to experimental data. AET uses the full envelopes of seismic records including scattered coda waves to obtain information about the distribution of absorption and small-scale heterogeneity which provide complementary information about the investigated medium. Being below the resolution limit this small-scale structure cannot be resolved by conventional tomography but still affects wave propagation by attenuating ballistic waves and generating scattered waves. Using ultrasound data from embedded sensors in a meter-sized concrete specimen we image the distribution of absorption and heterogeneity expressed by the intrinsic quality factor Q−1 and the fluctuation strength ɛ that characterizes the strength of the heterogeneity. The forward problem is solved by modeling the 2-D multiple nonisotropic scattering in an acoustic medium with spatially variable heterogeneity and attenuation using the Monte-Carlo method. Gradients for the model updates are obtained by convolution with the back-propagated envelope misfit using the adjoint formalism in analogy to full waveform inversion.
We use a late coda time window to invert for absorption and an earlier time window to infer the distribution of heterogeneity. The results successfully locate an area of salt oncrete with increased scattering and concentric anomalies of intrinsic attenuation. The resolution test shows that the recovered anomalies constitute reasonable representations of internal structure of the specimen.
KW - Ultrasound
KW - Scattering
KW - Tomography
KW - Concrete
KW - Heterogeneity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563163
DO - https://doi.org/10.1029/2022JB024972
SN - 2169-9313
VL - 127
IS - 11
SP - 1
EP - 21
PB - American Geophysical Union
AN - OPUS4-56316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Arndt, R.W.
A1 - Grosse, C.U,
A1 - Maehner, D.
A1 - Niederleithinger, Ernst
A1 - Taffe, A.
A1 - Algernon, D.
A1 - Berger, J.
A1 - Kessler, S.
A1 - Krueger, M.
A1 - Kruschwitz, Sabine
A1 - Ufermann-Wallmeier, D.
A1 - Walther, A.
T1 - Non-destructive testing in civil engineering: A memorandum for teaching at German-speaking universities
N2 - This contribution summarizes actual developments and draft fundamental teaching topics in the field of nondestructive testing in civil engineering (NDT-CE). It is based on the first memorandum on teaching and research in the field of NDT-CE at German speaking universities and provides an overview of the academic education and highlights possible focuses, especially in teaching but also takes into account noteworthy developments and topics in research in the field of NDT-CE.
Suggestions are given for the development and advancement of the teaching curricula in regards to a comprehensive and sound professional education of students in civil engineering and adjacent disciplines.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Curriculum
KW - NDT-CE
KW - University
KW - Competencies
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563269
UR - https://www.ndt.net/article/ndtce2022/paper/61547_manuscript.pdf
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-56326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epple, Niklas
A1 - Niederleithinger, Ernst
A1 - Fontoura Barroso, Daniel
T1 - Coda Wave Interferometry for Monitoring Bridges with Embedded Ultrasonic Transducers – Lessons Learned at the Gänstorbrücke Bridge Ulm, Germany
N2 - Ultrasonic Coda Wave interferometry has the potential to detect minute changes in scattering materials like concrete. By permanently installing ultrasonic transducers in concrete, DFG Research unit CoDA aims to develop methods for concrete damage assessment in Germany's aging infrastructure. To test the methods developed in simulations and laboratory experiments on a large scale, we have implemented several ultrasonic transducers at the Gänstorbrücke Ulm, one of Germany's most monitored road bridges. Since fall 2020 we are monitoring parts of the center of the Bridge, as well as an abutment, and compare the results to the commercial monitoring system. All data is recorded with a self-made data collection device, the so-called W-Box, and analyzed with different coda wave-based algorithms to detect signal and volumetric velocity changes. The long-term measurements show that the influence of temperature changes on strains and therefore ultrasound velocity changes calculated with coda waves can be monitored. The capabilities and limitations of the coda wave-based monitoring system are tested in a controlled experiment. Static loading using a truck with varying loads at several positions allows the calibration of the system to improve the detectability of possibly damaging loads and changes induced by this loading. A map of velocity change analyzing data from this load experiment shows that the influence of load on the material and strain distribution can be detected with array measurements.
T2 - NDT-CE 2022 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Coda Wave Interferometry
KW - Ultrasound
KW - Embedded sensors
KW - Bridge Monitoring
KW - Load Experiment
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564531
SP - 1
EP - 8
AN - OPUS4-56453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rabe, U.
A1 - Pudovikov, S.
A1 - Herrmann, H.-G.
A1 - Wiggenhauser, H.
A1 - Prabhakara, Prathik
A1 - Niederleithinger, Ernst
T1 - Evaluation of retroreflective corner echo for detection of surface breaking cracks in concrete by ultrasound
N2 - The retroreflective corner echo is used, for example, in ultrasonic non-destructive testing of metals to find fatigue cracks in tubes or shafts. If the much weaker crack tip signal is additionally detected, the crack length can also be determined. A corner reflection occurs in cases of surface breaking cracks with predominantly perpendicular orientation to the surface. The intensity of the corner reflection depends on the angle of incidence and on the ultrasonic wave mode used. For the reliable detection of vertical surface breaking cracks in metals, transversal waves are commonly used, which propagate at an angle of 37° to 53° to the inspection surface. As shown in this contribution, the wide spread low frequency ultrasonic arrays with dry point contact sources available for ultrasonic testing of concrete also allow to receive corner echoes. These devices generate transversal waves in concrete structures with a large divergence of the sound field. A series of experiments was carried out with such dry point contact arrays on concrete specimens with artificial test defects and controlled induced cracks of different depths. The ultrasonic time-of-flight signals were recorded, exported and reconstructed utilising the SAFT (Synthetic Aperture Focusing Technique) algorithm. The SAFT reconstruction parameters were adjusted to visualize the corner echo indication. As will be shown, with this targeted processing, the reproducible detection of surface breaking cracks in concrete is possible. The retroreflective corner echo can thus be exploited in civil engineering for non-destructive inspection of concrete.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Concrete
KW - Crack depth
KW - Ultrasound
KW - SAFT
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563365
UR - https://www.ndt.net/article/ndtce2022/paper/27256_manuscript.pdf
IS - 27256
SP - 1
EP - 4
PB - NDT.net
AN - OPUS4-56336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Landis, E.
A1 - Hassefras, Emiel
A1 - Oesch, Tyler
A1 - Niederleithinger, Ernst
T1 - A Microstructural Basis for Diffuse Ultrasound in Concrete
N2 - Attenuation of ultrasonic signals in concrete has the potential to carry much information about the microstructure of the material. In this work a series of concrete specimens of varying porosities and pore size distributions were internally imaged with x-ray computed tomography (CT), and then subsequently examined with throughtransmission ultrasound. The CT images were used to quantify both capillary porosity of cement paste as well as internal interfaces that are likely to produce elastic wave scattering. Ultrasound signals were represented as a diffusion process such that absorption and scattering attenuation could be isolated. As implemented, the diffusion model was a poor predictor of capillary porosity, while diffusivity was a reasonable predictor of scattering interfaces. Diffusivity was found to scale extremely well with small scale porosity, which made it a good predictor of compressive strength.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Concrete
KW - X-ray tomography
KW - Ultrasound
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563371
UR - https://www.ndt.net/article/ndtce2022/paper/61592_manuscript.pdf
SP - 1
EP - 4
PB - NDT.net
AN - OPUS4-56337
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
A1 - Buske, S.
A1 - Büttner, C.
T1 - Application of Elastic P-SV Reverse Time Migration to Synthetic Ultrasonic Echo Data from Concrete Members
N2 - The ultrasonic echo technique is frequently used in non-destructive testing (NDT) of concrete structures for thickness measurements, geometry determinations as well as localization of built-in components. To improve ultrasonic imaging of complex structures in concrete, we transferred a geophysical imaging technique, the reverse time migration (RTM), to NDT in civil engineering. In contrast to the conventionally used synthetic aperture focusing technique (SAFT) algorithms, RTM is a wavefield continuation method in time and uses the full wave equation. Thus, RTM can handle complicated wave propagations in any direction without dip limitation. In this paper, we focused on the application and evaluation of a two-dimensional (2D) elastic RTM algorithm considering compressional waves, vertically polarized shear waves, and Rayleigh waves. We tested the elastic RTM routine on synthetic ultrasonic echo data generated with a 2D concrete model consisting of several steps and circular air inclusions. As these complex structures can often be found in real-world NDT use cases, their imaging is especially important. By using elastic RTM, we were able to clearly reproduce vertical reflectors and lower edges of circular air voids inside our numerical concrete model. Such structures cannot be imaged with conventional SAFT algorithms. Furthermore, the used elastic RTM approach also yielded a better reconstruction of a horizontal reflector and upper boundaries of circular air inclusions. Our encouraging results demonstrate that elastic RTM has the potential to significantly improve the imaging of complex concrete structures and, thus, is a step forward for detailed, high-quality ultrasonic NDT in civil engineering.
KW - Concrete
KW - Ultrasound
KW - Imaging
KW - Reverse time migration
KW - Elastic
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580680
DO - https://doi.org/10.1007/s10921-023-00962-w
SN - 0195-9298
VL - 42
IS - 3
SP - 1
EP - 18
PB - Springer Nature
AN - OPUS4-58068
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, U.
A1 - Pudovikov, S.
A1 - Herrmann, H.-G.
A1 - Wiggenhauser, H.
A1 - Prabhakara, Prathik
A1 - Niederleithinger, Ernst
T1 - Using the Corner Reflection for Depth Evaluation of Surface Breaking Cracks in Concrete by Ultrasound
N2 - The corner echo is a well-known effect in ultrasonic testing, which allows detection of surface breaking cracks with predominantly perpendicular orientation to the surface as, for example, corrosion cracks in metal pipes or shafts. This echo is formed by two planes, the surface of the crack and the surface which the crack breaks. It can also be classified as a half-skip method, since a reflection of the pulse occurs on the backwall before the reflection at the defect takes place. In combination with the diffraction from the crack tip, the corner echo also allows crack sizing. As shown in this paper, the corner reflection can be used in civil engineering for nondestructive inspection of concrete. Commercially available low frequency ultrasonic arrays with dry point contact sources generate SH transversal waves with sufficient divergence of the sound field in order to detect corner reflections. Ultrasonic line-scans and area-scans were acquired with a linear array on flat concrete specimens, and the data were reconstructed by the Synthetic aperture focusing technique. If the angles and the area of reconstruction are chosen accordingly, the corner echo reflection can be distinguished from other ultrasonic information. The corner echo can thus be used as a method for deciding whether a crack is a partial-depth crack or a full-depth crack and thus for obtaining a statement about crack depth. This paper presents corresponding experimental results obtained on concrete specimens with artificial test defects and cracks induced under controlled conditions.
KW - Ultrasound
KW - Crack depth
KW - Concrete
KW - Corner echo
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574631
DO - https://doi.org/10.1007/s10921-023-00956-8
SN - 0195-9298
VL - 42
IS - 2
SP - 1
EP - 19
PB - Springer Nature
AN - OPUS4-57463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maack, Stefan
A1 - Küttenbaum, Stefan
A1 - Bühling, Benjamin
A1 - Borchardt-Giers, Kerstin
A1 - Aßmann, Norman
A1 - Niederleithinger, Ernst
T1 - Low frequency ultrasonic pulse-echo datasets for object detection and thickness measurement in concrete specimens as testing tasks in civil engineering
N2 - The dataset contains raw data gathered with the ultrasonic pulse-echo method on concrete specimens. The surfaces of the measuring objects were automatically scanned point by point. Pulse-echo measurements were performed at each of these measuring points. The test specimens represent two typical testing tasks in construction industry: the detection of objects and the determination of dimensions to describe the geometry of components. By automating the measurement process, the different test scenarios are examined with a high repeatability, precision and measuring point density. Longitu- dinal and transversal waves were used and the geometrical aperture of the testing system was varied. The low-frequency probes operate in a range of up to approximately 150 kHz. In addition to the specification of the geometrical dimensions of the individual probes, the directivity pattern and the sound field characteristics are provided. The raw data are stored in a universally readable format. The length of each time signal (A-scan) is two milliseconds and the sampling rate is two mega-samples per second. The provided data can be used for comparative studies in signal analysis, imag- ing and interpretation as well as for evaluation pur- poses in different, practically relevant testing scenarios.
KW - Validation
KW - Puls-echo method
KW - Ultrasonic
KW - Non-destructive testing
KW - SAFT
KW - Reconstruction algorithm
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575185
DO - https://doi.org/10.1016/j.dib.2023.109233
SN - 2352-3409
VL - 48
SP - 1
EP - 16
PB - Elsevier Inc.
AN - OPUS4-57518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prabhakara, Prathik
A1 - Lay, Vera
A1 - Mielentz, Frank
A1 - Niederleithinger, Ernst
A1 - Behrens, Matthias
T1 - Enhancing the Performance of a Large Aperture Ultrasound System (LAUS): A Combined Approach of Simulation and Measurement for Transmitter–Receiver Optimization
N2 - The Large Aperture Ultrasound System (LAUS) developed at BAM is known for its ability to penetrate thick objects, especially concrete structures commonly used in nuclear waste storage and other applications in civil engineering. Although the current system effectively penetrates up to ~9 m, further optimization is imperative to enhance the safety and integrity of disposal structures for radioactive or toxic waste. This study focuses on enhancing the system’s efficiency by optimizing the transducer spacing, ensuring that resolution is not compromised. An array of twelve horizontal shear wave transducers was used to find a balance between penetration depth and resolution. Systematic adjustments of the spacing between transmitter and receiver units were undertaken based on target depth ranges of known reflectors at depth ranges from 5 m to 10 m. The trade-offs between resolution and artifact generation were meticulously assessed. This comprehensive study employs a dual approach using both simulations and measurements to investigate the performance of transducer units spaced at 10 cm, 20 cm, 30 cm, and 40 cm. We found that for depths up to 5 m, a spacing of 10 cm for LAUS transducer units provided the best resolution as confirmed by both simulations and measurements. This optimal distance is particularly effective in achieving clear reflections and a satisfactory signal-to-noise ratio (SNR) in imaging scenarios with materials such as thick concrete structures. However, when targeting depths greater than 10 m, we recommend increasing the distance between the transducers to 20 cm. This increased spacing improves the SNR in comparison to other spacings, as seen in the simulation of a 10 m deep backwall. Our results emphasize the critical role of transducer spacing in achieving the desired SNR and resolution, especially in the context of depth imaging requirements for LAUS applications. In addition to the transducer spacing, different distances between individual sets of measurement positions were tested. Overall, keeping the minimal possible distance between measurement position offsets provides the best imaging results at greater depths. The proposed optimizations for the LAUS in this study are primarily relevant to applications on massive nuclear structures for nuclear waste management. This research highlights the need for better LAUS efficiency in applications such as sealing structures, laying the foundation for future technological advances in this field.
KW - Engineered barrier system
KW - Phased array technique
KW - Ultrasonic testing
KW - Non-destructive testing in civil engineering
KW - Seismic migration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592426
DO - https://doi.org/10.3390/s24010100
VL - 24
IS - 1
SP - 1
EP - 23
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-59242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
A1 - Maack, Stefan
A1 - Buske, Stefan
T1 - Application of iterative elastic SH reverse time migration to synthetic ultrasonic echo data
N2 - The ultrasonic echo technique is widely used in non-destructive testing (NDT) of concrete objects for thickness measurements, geometry determinations and localization of built-in components. To improve ultrasonic imaging of complex concrete structures, we transferred a seismic imaging technique, the Reverse Time Migration (RTM), to NDT in civil engineering. RTM, in contrast to the conventionally used synthetic aperture focusing technique (SAFT) algorithms, considers all wavefield types and thus, can handle complex wave propagations in any direction with no limit on velocity variations and reflector dip. In this paper, we focused on the development, application and evaluation of a two-dimensional elastic RTM algorithm considering horizontally polarized shear (SH) waves only. We applied the elastic SH RTM routine to synthetic ultrasonic echo SH-wave data generated with a concrete model incorporating several steps and circular cavities. As these features can often be found in real-world NDT use cases, their imaging is extremely important. By using elastic SH RTM, we were able to clearly reproduce almost all reflectors inside the concrete model including the vertical step edges and the cross sections of the cavities.We were also capable to show that more features could be mapped compared to SAFT, and that imaging of complex reflectors could be sharpened compared to elastic P-SV (compressional-vertically polarized shear) RTM. Our promising results illustrate that elastic SH RTM has the potential to significantly enhance the reconstruction of challenging concrete structures, representing an important step forward for precise, high-quality ultrasonic NDT in civil engineering.
KW - Ultrasonic echo technique
KW - Concrete structures
KW - Elastic reverse time migration
KW - Synthetic aperture focusing technique
KW - Horizontally polarized shear waves
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591716
DO - https://doi.org/10.1007/s10921-023-01010-3
SN - 1573-4862
VL - 43
SP - 1
EP - 16
PB - Springer Science and Business Media
CY - Dordrecht
AN - OPUS4-59171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Timofeev, Juri
A1 - Azari, H.
A1 - Satyanarayana, R.
T1 - Controlled Creating of Delaminations in Concrete for Nondestructive Testing
N2 - Locating and sizing delaminations is a common inspection task in the maintenance and quality control of construction and rehabilitation. Their detection is an important area of application of nondestructive testing in civil engineering (NDT-CE). To improve this application, NDT test systems and test solutions must be compared, for which specimens containing well-defined delaminations are needed to serve as a reference. Currently, there are no widely accepted procedures available for creating such flaws locally and reproducibly. This study presents procedures for creating artificial delaminations repeatably and as close as possible to natural delaminations. To produce the discontinuities only substances were used which can occur in concrete components and do not affect the application of NDT-CE methods. Ultrasonic pulse-echo (UPE) was used to test the flaws in the specimens. The delaminations were created by applying expansive mortar in prepared through holes. Three specimens with two delaminations each were built and tested using UPE.
KW - Concrete
KW - Reference
KW - Delamination
KW - Test specimen
KW - Non-destructive testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595201
DO - https://doi.org/10.1007/s10921-023-01044-7
SN - 0195-9298
VL - 43
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-59520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lay, Vera
A1 - Effner, Ute
A1 - Niederleithinger, Ernst
A1 - Arendt, J.
A1 - Hofmann, M.
A1 - Kudla, W.
T1 - Ultrasonic quality assurance at magnesia shotcrete sealing structures
N2 - Engineered barriers are a key element to enable safe nuclear waste disposal. One method currently under research for their construction is magnesia concrete applied in a shotcrete procedure. In this study, the ultrasonic echo method is evaluated as a means for quality assurance. Imaging of internal structures (backwall, boreholes) and defects, such as delamination, has successfully been achieved in the shotcrete. Additionally, detailed information about the potential cause of selected reflectors are obtained by phase analysis. In several test blocks of various sizes, no consistent concrete section boundaries have been found by ultrasonic imaging, which was verified by subsequent drilling and complementary tests. An experiment with artificial defects imitating cracks, air-filled voids, and material with lower density has been challenging and shows the limitations of the current methods. Although significant defects, such as a large delamination, are reliably identified, several smaller defects are not identified. Generally, ultrasonic imaging provides a suitable base as a mean for quality assurance during and after the construction of sealing structures. However, further developments are required to enhance the reliability of the method and a full validation is still pending. Still, the method has potential to increase the safety of nuclear waste repositories.
KW - Ultrasound
KW - Imaging
KW - Engineered barrier systems
KW - Underground
KW - Shotcrete
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563170
DO - https://doi.org/10.3390/s22228717
SN - 1424-8220
VL - 22
IS - 22
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-56317
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, T.
A1 - Niederleithinger, Ernst
T1 - Combining Passive and Active Ultrasonic Stress Wave Monitoring Techniques: Opportunities for Condition Evaluation of Concrete Structures
N2 - Concrete structures are invaluable assets to a society and managing them efficiently and effectively can be supported by information gathered through structural health monitoring (SHM). In this paper, a combined approach based on passive, i.e., acoustic emission (AE), and active, i.e., ultrasonic stress wave (USW) monitoring techniques for application to concrete structures is proposed and evaluated. While AE and USW are based on the same underlying physics, i.e., wave motion in solids, they differ fundamentally with respect to the nature of the source. For the former, external stimuli such as mechanical loads or temperature cause the rapid release of energy from initially unknown locations. As a result, AE events are unique and cannot be repeated. For the latter, a known source at a known location is employed at a specified time. This approach is thus controlled and repeatable. It is
argued that a combination of these two techniques has the potential to provide a more comprehensive picture of ongoing fracture processes, damage progression, as well as slowly occurring aging and degradation mechanisms.
This combined approach does thus promise new opportunities to support condition assessment of concrete structures. After providing an overview and comparison of the two techniques, results, and observations from a full-scale laboratory experiment and an in-service bridge monitoring study are discussed to demonstrate the promise of the proposed combined monitoring approach. Finally, suggestions for further work are presented.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Ultrasound
KW - Acoustic emission
KW - Concrete structures
KW - Monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563242
UR - https://www.ndt.net/article/ndtce2022/paper/61607_manuscript.pdf
SP - 1
EP - 11
PB - NDT.net
AN - OPUS4-56324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feistkorn, S.
A1 - Algernon, D.
A1 - Arndt, R.
A1 - Ebell, Gino
A1 - Friese, M.
A1 - Grosse, C. U.
A1 - Holstein, R.
A1 - Niederleithinger, Ernst
A1 - Schickert, M.
A1 - Schulze, S.
A1 - Taffe, A.
A1 - Walther, A.
A1 - Wolf, J.
A1 - Zoega, A.
A1 - Zwanzig, M.
T1 - Introduction to DIN 4871: Qualification of NDT Personnel in Civil Engineering (NDT-CE)
N2 - Recently, non-destructive testing in civil engineering (NDT-CE), in particular of concrete components, has successfully mastered the leap from research to practice. Several methods have been established for field inspections to determine the concrete cover of reinforcement or to estimate the compressive strength as well as other parameters related to the concrete material. In addition, the application of nondestructive testing is indispensable, if information about the inner structure - such as the location of rebars and tendon ducts or the damage-related condition assessment to detect grouting defects, honeycombs, delamination, or corrosion - is required. Besides the selection of a suitable NDT method and an appropriate inspection system, the reliability of the results depends largely on the person who applies the non-destructive inspection technique and evaluates the inspection results. To ensure a high quality of non-destructive concrete evaluation as well as to keep the uncertainty caused by the inspection personnel to a minimum, structured, consistent and regulated theoretical as well as practical training of inspection personnel is essential. To close this gap, the subcommittee of education (UA-A) within the committee for NDT-CE of the German Society for Nondestructive Testing (DGZfP) has been reactivated in 2018 to establish uniform training standards for nondestructive concrete inspections in the long term. The subcommittee consists of scientists, practitioners, authorities, and clients. So far, the national standard DIN 4871 “Non-destructive testing - Qualification and Certification of NDT personnel in Civil Engineering (NDT-CE)” was developed and is currently under review. This standard considers the civil-industry-specifics, for example, that standards for NDT of concrete, as well as related product standards with a few exceptions, still do not exist at the moment. Within this presentation, the concept, the connection to ISO 9712 and other standards as well as an overview of the developed German standard DIN 4871 will be presented.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Non-destrucive testing
KW - Civil engineering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555250
UR - https://www.ndt.net/article/ndtce2022/paper/66594_manuscript.pdf
VL - 2022/09
SP - 1
EP - 12
PB - NDT.net
CY - Bad Breisig
AN - OPUS4-55525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Niederleithinger, Ernst
A1 - Guangliang, Y.
A1 - Mahon, D.
A1 - Gardner, S.
T1 - Muon tomography applied to assessment of concrete structures: First experiments and simulations.
N2 - Non-destructive techniques for reinforced or prestressed concrete inspection such as ultrasound or radar have found regular, successful practical application but sometimes suffer from limited resolution and
accuracy, imaging artefacts or restrictions in detecting certain features. Until the 1980s X-ray transmission was used in case of special demands and showed a much better resolution than other NDT techniques.
However, due to safety concerns and cost issues, this method is almost never used anymore. Muon tomography has received much attention recently. Novel detectors for cosmic muons and tomographic imaging algorithms have opened new fields of application. As a first step towards practical application in civil engineering and as a proof of concept we used an existing system to image the interior of a reference reinforced 600 kg concrete block. Even with a yet not optimized setup for this kind of investigation, the muon imaging results are at least of similar quality compared to ultrasonic and radar imaging, potentially even better. In a second step, we have performed simulations to assess the potential for a set of important testing problems such as grouting defects in tendon ducts. The next steps include the development of mobile detectors and optimizing acquisition and imaging parameters.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Muon tomography
KW - Concrete
KW - Inspection
KW - Simulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563224
UR - https://www.ndt.net/article/ndtce2022/paper/60943_manuscript.pdf
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-56322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
A1 - Buske, B.
T1 - Application of Elastic Reverse Time Migration to Ultrasonic Echo Data in Civil Engineering
N2 - To improve ultrasonic imaging of concrete structures, we transferred a seismic migration technique, the Reverse Time Migration (RTM), to non-destructive testing. A 2D elastic RTM algorithm was tested on synthetic ultrasonic echo data. Compared to the typically used synthetic aperture focusing technique (SAFT) as well as our acoustic RTM algorithm, the presented elastic RTM results show an enhancement in imaging vertical reflectors and complex features inside the 2D numerical concrete model.
T2 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Ultrasonic Echo Technique
KW - Reverse Time Migration
KW - Synthetic Aperture Focusing Technique
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561147
UR - https://www.ndt.net/article/ndtce2022/paper/60699_manuscript.pdf
SP - 1
EP - 6
AN - OPUS4-56114
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Abraham, O.
A1 - Niederleithinger, Ernst
A1 - Schmidt, F.
A1 - Sörensen, J.D.
A1 - Thöns, S.
A1 - Chapeleau, X.
A1 - Ferria, H.
T1 - Infrastar Training School on Fatigue and Reliability Analysis of Structures - Training for Assessment of Risk
N2 - The Infrastar training school provides lectures and hands-on training to Master and PhD students, early-stage researchers and (young) professionals on all aspects of asset management of civil infrastructures with respect to fatigue of materials. It is organized yearly since 2019 and up to 20 profiles are selected to attend the 3.5-day training.
A team of 7 teachers provides insight in multi-disciplinary and intersectoral basic concepts in three core fields, ranging from the design to the dismantling of the structures (bridges and wind turbines):
1. Monitoring and auscultation,
2. Structural and action models,
3. Reliability, risk and decision analyses.
Each year, a recognized expert is invited to deliver a keynote lecture to raise interest in a specific aspect of one of the fields covered. The presentation is recorded and published on the training school website.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Doctoral School
KW - Multidisciplinary
KW - Fatigue
KW - Reliability
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563253
UR - https://www.ndt.net/article/ndtce2022/paper/61021_manuscript.pdf
SP - 1
EP - 3
PB - NDT.net
AN - OPUS4-56325
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolditz, O.
A1 - Jacques, D.
A1 - Claret, F.
A1 - Bertrand, J.
A1 - Churakov, S. V.
A1 - Debayle, C.
A1 - Diaconu, D.
A1 - Fuzik, K.
A1 - Garcia, D.
A1 - Graebling, N.
A1 - Grambow, B.
A1 - Holt, E.
A1 - Idiart, A.
A1 - Leira, P.
A1 - Montoya, V.
A1 - Niederleithinger, Ernst
A1 - Olin, M.
A1 - Pfingsten, W.
A1 - Prasianakis, N. I.
A1 - Rink, K.
A1 - Sampier, J.
A1 - Szöke, I.
A1 - Szöke, R.
A1 - Theodon, L.
A1 - Wendling, J.
T1 - Digitalisation for nuclear waste management: predisposal and disposal
N2 - Data science (digitalisation and artificial intelligence) became more than an important facilitator for many domains in fundamental and applied sciences as well as industry and is disrupting the way of research already to a large extent. Originally, data sciences were viewed to be well-suited, especially, for data-intensive applications such as image processing, pattern recognition, etc. In the recent past, particularly, data-driven and physics-inspired machine learning methods have been developed to an extent that they accelerate numerical simulations and became directly usable for applications related to the nuclear waste management cycle. In addition to process-based approaches for creating surrogate models, other disciplines such as virtual reality methods and high-performance computing are leveraging the potential of data sciences more and more. The present challenge is utilising the best models, input data and monitoring information to integrate multi-chemical-physical, coupled processes, multi-scale and probabilistic simulations in Digital Twins (DTw) able to mirror or predict the performance of its corresponding physical twins. Therefore, the main target of the Topical Collection is exploring how the development of DTw can benefit the development of safe, efficient solutions for the pre-disposal and disposal of radioactive waste. A particular challenge for DTw in radioactive waste management is the combination of concepts from geological modelling and underground construction which will be addressed by linking structural and multi-physics/chemistry process models to building or tunnel information models. As for technical systems, engineered structures a variety of DTw approaches already exist, the development of DTw concepts for geological systems poses a particular challenge when taking the complexities (structures and processes) and uncertainties at extremely varying time and spatial scales of subsurface environments into account.
KW - Data science
KW - Digitalization
KW - Nuclear waste
KW - Disposal
KW - Predisposal
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569387
DO - https://doi.org/10.1007/s12665-022-10675-4
SN - 1866-6280
VL - 82
IS - 1
SP - 1
EP - 11
PB - Springer
AN - OPUS4-56938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prabhakara, Prathik
A1 - Mielentz, Frank
A1 - Stolpe, Heiko
A1 - Behrens, Matthias
A1 - Lay, Vera
A1 - Niederleithinger, Ernst
T1 - Validation of novel ultrasonic phased array borehole probe by using simulation and measurement
N2 - Low-frequency ultrasonic testing is a well-established non-destructive testing (NDT) method in civil engineering for material characterization and the localization of cracks, reinforcing bars and delamination. A novel ultrasonic borehole probe is developed for in situ quality assurance of sealing structures in radioactive waste repositories using existing research boreholes. The aim is to examine the sealing structures made of salt concrete for any possible cracks and delamination and to localize built-in components. A prototype has been developed using 12 individual horizontal dry point contact (DPC) shear wave transducers separated by equidistant transmitter/receiver arrays. The probe is equipped with a commercially available portable ultrasonic flaw detector used in the NDT civil engineering industry. To increase the sound pressure generated, the number of transducers in the novel probe is increased to 32 transducers. In addition, the timed excitation of each transducer directs a focused beam of sound to a specific angle and distance based on the previously calculated delay time. This narrows the sensitivity of test volume and improves the signal-to-noise ratio of the received signals. In this paper, the newly designed phased array borehole probe is validated by beam computation in the CIVA software and experimental investigations on a half-cylindrical test specimen to investigate the directional characteristics. In combination with geophysical reconstruction methods, it is expected that an optimised radiation pattern of the probe will improve the signal quality and thus increase the reliability of the imaging results. This is an important consideration for the construction of safe sealing structures for the safe disposal of radioactive or toxic waste.
KW - Ultrasound
KW - Phased array
KW - Concrete
KW - Borehole
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565722
DO - https://doi.org/10.3390/s22249823
SN - 1424-8220
VL - 22
IS - 24
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-56572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holt, E.
A1 - Oksa, M.
A1 - Nieminen, M.
A1 - Abdelouas, A.
A1 - Banford, A.
A1 - Fournier, M.
A1 - Mennecart, T.
A1 - Niederleithinger, Ernst
T1 - Predisposal conditioning, treatment, and performance assessment of radioactive waste streams
N2 - Before the final disposal of radioactive wastes, various processes can be implemented to optimise the waste form. This can include different chemical and physical treatments, such as thermal treatment for waste reduction, waste conditioning for homogenisation and waste immobilisation for stabilisation prior to packaging and interim storage. Ensuring the durability and safety of the waste matrices and packages through performance and condition assessment is important for waste owners, waste management organisations, regulators and wider stakeholder communities. Technical achievements and lessons learned from the THERAMIN and PREDIS projects focused on low- and intermediate-level waste handling is shared here. The recently completed project on Thermal Treatment for Radioactive Waste Minimization and Hazard Reduction (THERAMIN) made advances in demonstrating the feasibility of different thermal treatment techniques to reduce volume and immobilise different streams of radioactive waste (LILW) prior to disposal. The Pre-Disposal Management of Radioactive Waste (PREDIS) project addresses innovations in the treatment of metallic materials, liquid organic waste and solid organic waste, which can result from nuclear power plant operation, decommissioning and other industrial processes. The project also addresses digitalisation solutions for improved safety and efficiency in handling and assessing cemented-waste packages in extended interim surface storage.
KW - Radioactive waste
KW - Predisposal
KW - Treatment
KW - Monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567276
DO - https://doi.org/10.1051/epjn/2022036
SN - 2491-9292
VL - 8
SP - 1
EP - 6
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-56727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Prabhakara, Prathik
A1 - Mielentz, Frank
A1 - Stolpe, Heiko
A1 - Behrens, Matthias
A1 - Lay, Vera
A1 - Niederleithinger, Ernst
T1 - Construction and validation of a novel phased array borehole probe for ultrasonic investigations at sealing structures in radioactive repositories
N2 - A new type of ultrasonic borehole probe is currently under development for the quality assurance of sealing structures in radioactive waste repositories using existing research boreholes. The goal is to examine the sealing structures made of salt concrete for possible cracks, delamination, and embedded objects. Earlier prototype probes use 12 or 16 individual dry point contact (DPC) horizontal shear wave transducers grouped into a transmitter and a receiver array, each made up of six or eight individual transducers. They are operated with a commercially available portable ultrasonic flaw detector used in the civil engineering industry. To increase the generated sound pressure of the borehole probe, the number of transducers in the novel probe is increased to 32. In addition, timed excitation of each probe is used to direct a focused sound beam to a specific angle and distance based on calculated time delays. Hence, the sensitive test volume is limited, and the signal-to-noise ratio of the received signals is improved. This paper presents the validation of the newly developed phased array borehole probe by beam computation in CIVA software and experimental investigations on a semi-cylindrical test specimen to investigate the directional characteristics. In combination with geophysical reconstruction techniques, an optimised radiation pattern of the probe is expected to improve the signal quality and thus increase the reliability of the imaging results.
This is of great importance for the construction of safe sealing structures needed for the disposal of radioactive or toxic waste.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Borehole probe
KW - Phased array technique
KW - SealWasteSafe
KW - Monitoring
KW - Engineered barrier;
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568016
SN - 1435-4934
SP - 1
EP - 4
PB - NDT.net
AN - OPUS4-56801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holt, Erika
A1 - Oksa, Maria
A1 - Banford, Anthony
A1 - Carbol, Paul
A1 - Abdelouas, Abdesselam
A1 - Giboire, Isabelle
A1 - Mennecart, Thierry
A1 - Niederleithinger, Ernst
T1 - Predisposal Radioactive Waste Management (PREDIS) Project Final Achievements and Impacts Overview
N2 - The PREDIS project on Predisposal of Radioactive Waste has succeeded in developing and implementing new methods, processes and technologies for treatment of challenging low-level waste (LLW) and intermediate level waste (ILW) streams. Over the 4-year duration, this Euratom project of 47 partners from 17 Member States has worked in close collaboration with 25 End User industrial members to advance the technologies associated with predisposal issues. This has included characterisation followed by treatment, conditioning and processing of metallics, liquid organic and solid organic wastes as well as with digitalization technologies for assessing performance of concrete waste packages and pre-disposal storage. Long-term modelling and performance testing have been done to verify the safety and effectiveness of the new or enhanced solutions. Value Assessments were done for some of the new solutions to ensure implementors would have sufficient tools for making choices about the potential implementation. This included life-cycle assessment of quantitative sustainability indicators and life cycle-costing for economic indicators. This project addressed new guidance on Waste Acceptance Criteria and contributed with a revised Strategic Research Agenda to guide future predisposal activities, complimentary to the holistic waste management programme. Knowledge Management actions were also an integral part of the whole project to foster competence development and capturing knowledge. Actions included training, mobility, and guidance especially through online forums such as webinars and digital training. This paper provides a snapshot of some of the key outcomes and impacts from the project, from technical as well as strategic and knowledge perspectives.
KW - Nuclear waste
KW - Pre-disposal
KW - Intermediate storage
KW - Treatment
KW - Monitoring
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638480
DO - https://doi.org/10.1051/epjn/2025028
SN - 2491-9292
VL - 11
SP - 1
EP - 7
PB - EDP Sciences
AN - OPUS4-63848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Morichi, M.
A1 - Fanchini, E.
A1 - Bruggemann, C.
A1 - Perot, B.
A1 - Ricard, D.
A1 - Niederleithinger, Ernst
T1 - Developments and experiences of the CHANCE, MICADO and PREDIS projects in radioactive waste characterization
N2 - Characterization is a very important step in dealing with materials and waste streams generated during the operational and decommissioning phases of nuclear installations, including nuclear power plants. Characterization allows differentiation between materials that can be released from regulatory control and those that require further treatment and conditioning to become a stable waste form suitable for future storage and final disposal according to its waste classification. Characterization is also needed in the pre-disposal stages of radioactive waste management to demonstrate compliance with the waste acceptance criteria of the facilities that will accept the different waste forms. This work will present the strategies developed and implemented by the three projects for in-depth and accurate waste characterization and investigation of the different radioactive waste packages considered. CHANCE, MICADO, and PREDIS will present their goals, the methods developed, the technologies used and the (preliminary) results contributing to the improvement of the safety and the data and information quality of the waste packages analyzed at the different stages of the waste management process. Special emphasis will also be given to complementary approaches highlighting the usability of the technologies, the accessibility of the data, and the problem-solving of the three projects within the European panorama.
KW - Waste management
KW - Radioactive waste
KW - Waste chracterization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571872
DO - https://doi.org/10.1051/epjn/2022052
SN - 2491-9292
VL - 9
IS - 12
SP - 1
EP - 11
PB - EPJ Nuclear Sci. Technol.
AN - OPUS4-57187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
A1 - Büttner, Christoph
A1 - Buske, Stefan
T1 - Application of iterative elastic reverse time migration to shear horizontal ultrasonic echo data obtained at a concrete step specimen
N2 - The ultrasonic echo technique is broadly applied in non‐destructive testing (NDT) of concrete structures involving tasks such as measuring thickness, determining geometry and locating built‐in elements. To address the challenge of enhancing ultrasonic imaging for complex concrete constructions, we adapted a seismic imaging algorithm – reverse time migration (RTM) – for NDT in civil engineering. Unlike the traditionally applied synthetic aperture focusing technique (SAFT), RTM takes into account the full wavefield including primary and reflected arrivals as well as multiples. This capability enables RTM to effectively handle all wave phenomena, unlimited by changes in velocity and reflector inclinations. This paper concentrates on applying and evaluating a two‐dimensional elastic RTM algorithm that specifically addresses horizontally polarized shear (SH) waves only, as these are predominantly used in ultrasonic NDT of concrete structures. The elastic SH RTM algorithm was deployed for imaging real ultrasonic echo SH‐wave data obtained at a concrete specimen exhibiting a complex back wall geometry and containing four tendon ducts. As these features are frequently encountered in practical NDT scenarios, their precise imaging holds significant importance. By applying the elastic SH RTM algorithm, we successfully reproduced nearly all reflectors within the concrete specimen. In particular, we were capable of accurately reconstructing all vertically oriented reflectors as well as the circular cross sections of three tendon ducts, which was not achievable with traditional SAFT imaging. These findings demonstrate that elastic SH RTM holds the ability to considerably improve the imaging of complex concrete geometries, marking a crucial advancement for accurate, high‐quality ultrasonic NDT in civil engineering.
KW - Engineering
KW - Finite-Difference Time Domain
KW - Non-Destructive
KW - Seismic
KW - Migration
KW - Ultrasonic-Echo Technique
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608744
DO - https://doi.org/10.1002/nsg.12318
SN - 1569-4445
VL - 2024
SP - 1
EP - 22
PB - Wiley
AN - OPUS4-60874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bahrami Eskandari, Ardalan
A1 - Nikkhoo, Ali
A1 - Hajirasouliha, Iman
T1 - Analyzing Vertical Earthquake Vibrations and Moving Vehicle Loads for Structural Health Monitoring and Vibration Suppression in Bridges
N2 - The design of bridges often overlooks the vertical component of earthquakes or considers it of secondary importance, despite compelling evidence indicating specific structural damage caused by primary earthquake waves. Conversely, during the operational phase, the combined influence of ground motion and moving loads from vehicles can significantly impact the structural health monitoring (SHM) of bridges. This study aims to evaluate the simultaneous effect of vertical earthquake vibrations and moving vehicle loads on simply supported bridges. The research employs a practical methodology based on the eigenfunction expansion method to analyze change of deflection due to the effect of these concurrent forces under seven different earthquake records. It is shown that within a realistic range of vehicle mass and velocity, the average of changing the maximum deflection at the mid-span of the main beam (denoted as M_n) reaches up to 163% under various scenarios. Subsequently, the seismic parameters influencing this phenomenon are identified through a statistical analysis of set of 100 different earthquake records with unique features. A linear regression equation is presented to predict the M_n based on the earthquake specific properties. Additionally, to control the vertical vibration of bridge systems, a novel vibration suppression system utilizing steel pipe dampers is introduced, and its reliability is examined across a broad spectrum of bridge flexural rigidity. The results indicate that the system's efficiency depends on M_n and the soil type of the bridge construction, enabling a reduction in structural sections (up to 27%) while achieving the same maximum target deflection in the initial state. This efficiency leads to a more economical design solution, emphasizing the potential benefits of the proposed system for practical application.
T2 - 11th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam, Germany
DA - 10.06.2024
KW - Bridge structures
KW - Vertical earthquakes
KW - Health monitoring
KW - Moving vehicles
KW - Suppressing vibrations
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604893
DO - https://doi.org/10.58286/29746
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-60489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bahrami Eskandari, Ardalan
A1 - Küttenbaum, Stefan
T1 - NDT Data-Supported Structural Reassessments based on Regression Relations in Measuring Data Analysis
N2 - Non-destructive Testing (NDT) provides valuable data about structural elements, supporting the assessment of existing infrastructures without incurring additional structural damage from inspections. Simultaneously, the uncertainty in measurement, which quantifies the quality of measurement results, plays a crucial role in decisions aimed at, e.g., optimizing maintenance strategies, rehabilitation works and Structural Health Monitoring (SHM) implementations. The Guide to the Expression of Uncertainty in Measurement (GUM) framework has already been considered for non-destructive concrete testing. Regarding that, extensive measurements with sophisticated scopes need to be conducted by experts as an obligatory process.
This study illustrates how NDT results describing the inner structure of a concrete element can effectively support the reassessment of bridges in operation. To achieve this, the study considers the various measurable positions of the resisting longitudinal tendons of a bridge structure to investigate the displacement change under dynamic service loads.
Furthermore, this study aims to simplify and optimize existing NDT data analysis procedures by employing regression analysis, enabling the detection of structural features. This regression analysis yields a modifier for determining the correct depth of an object within the structural element. The method is validated through laboratory experiments, including the use of an ultrasonic measurement system. As a result, it provides unbiased and accurately measured results, while ensuring that the measurement data can remain uncorrelated. Major advantages include efficient computation, a wider scope, and avoiding redundant information about the measuring process.
The findings demonstrate that employing the proposed NDT analysis method, with its enhanced practicability, can significantly augment the efficiency of NDT data-supported structural reassessments across various scenarios.
T2 - EWSHM 2024
CY - Potsdam, Germany
DA - 10.06.2024
KW - Existing structures
KW - Non-destructive testing
KW - Practicality measurement
KW - Bridge reassessment
KW - Statistical analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604825
DO - https://doi.org/10.58286/29714
SN - 1435-4934
SP - 1
EP - 9
PB - NDT.net
AN - OPUS4-60482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertola, N.
A1 - Schumacher, T.
A1 - Niederleithinger, Ernst
A1 - Bruehwiler, E.
T1 - Early detection of structural damage in UHPFRC structures through the combination of acoustic emission and ultrasonic stress wave monitoring
N2 - Ultra-High-Performance Fiber-Reinforced Cementitious Composite (UHPFRC) offers several advantages compared to concrete, notably due to the strain hardening behavior under tensile actions. Structures made of this composite material are lightweight and highly durable, thanks to the UHPFRC waterproofing quality. Nonetheless, the tensile behavior leads to a different cracking pattern than conventional concrete and is not fully understood yet. This paper presents a combined approach using both passive ultrasonic (US) stress wave (or acoustic emission) and active US stress wave monitoring to localize and quantify damage progression in a full-scale UHPFRC beam during experimental load testing. The proposed monitoring approach involves 24 US transducers that are embedded randomly throughout a 4.2- meter-long laboratory UHPFRC T-beam. Continuous monitoring enabled accurate localization of US stress sources caused by loading-induced cracking as well as from pulses generated by the embedded US transducers. This study shows that it is possible to predict the location and shape of the macro-crack that is linked to structural failure early on, i.e., just after the end of the elastic domain. This combined approach opens new possibilities to monitor the structural behavior and detect damage on UHPFRC structures before they affect the structural behavior in terms of deflection and strain.
T2 - 11th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam, Germany
DA - 11.6.2024
KW - UHPFRC
KW - Acoustic emission
KW - Damage detection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604708
UR - https://www.ndt.net/article/ewshm2024/papers/477_manuscript.pdf
DO - https://doi.org/10.58286/29698
SN - 1435-4934
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-60470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, T.
A1 - Bertola, N.
A1 - Epple, Niklas
A1 - Bruehwiler, E.
A1 - Niederleithinger, Ernst
T1 - Combined Passive and Active Ultrasonic Stress Wave Monitoring of Concrete Structures: An Overview of Data Analysis Techniques and Their Applications and Limitations
N2 - Combined passive ultrasonic (US) stress wave [better known as acoustic emission (AE)] and active US stress wave monitoring has been shown to provide a more holistic picture of ongoing fracture processes, damage progression, as well as slowly occurring aging and degradation mechanisms in concrete structures. Traditionally, different data analysis techniques have been used to analyze the data generated from these two monitoring techniques. For passive US stress wave monitoring, waveform amplitudes, hit rates, source localization, and b-value analysis, among others, have been used to detect and locate cracking. On the other hand, amplitude tracking, magnitude squared coherence (MSC), and coda wave interferometry (CWI) are examples of analyses that have been employed for active US stress wave monitoring. In this paper, we explore some of these data analysis techniques and show where their respective applications and limitations might be. After providing an overview of the monitoring approach and the different data analysis techniques, results and observations from selected laboratory experiments are discussed. Finally, suggestions for further work are proposed.
T2 - 11th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam, Germany
DA - 11.06.2024
KW - Ultrasound
KW - Acoustic emission
KW - Concrete
KW - Stress
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604687
UR - https://www.ndt.net/article/ewshm2024/papers/824_manuscript.pdf
DO - https://doi.org/10.58286/29863
SN - 1435-4934
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-60468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Skłodowska, Anna
A1 - Baensch, Franziska
A1 - Lay, Vera
A1 - Niederleithinger, Ernst
A1 - Kühne, Hans-Carsten
T1 - Acoustic emission monitoring for engineered barriers in nuclear waste disposal
N2 - To safely dispose of nuclear waste in underground facilities, engineered barrier systems are needed to seal shafts and galleries. The material used in these barriers must be adapted to the host rock parameters. Shrinking and cracking must be avoided to provide a barrier with almost zero permeability. For repositories in salt rock environments, several types of salt concrete (SC) are possible construction materials. Within the project SealWasteSafe, we compared the behavior of an innovative alkali-activated material (AAM) with standard SC in their hydration and hardening phase. To monitor the microstructural changes within the two materials SC and AAM, acoustic emission (AE) signals have been recorded for up to ~250 days on 340-litercubic specimens. The phenomenon of AE is defined as the emission of elastic waves in materials due to the release of localized internal energy. Such energy release can be caused by the nucleation of micro-fracture, e.g., in concrete while curing or when exposed to load. The occurrence of AE events gives first rough indications of microstructural changes and potentially occurring cracking and thus, provides insights for structural health monitoring (SHM). The results show, that for the first 28 days after casting, less AE activity was detected in the AAM compared to SC. After 61 days, in the AAM material, the number of AE events exceeded those observed in the SC. However, the majority of the AE detected and located in AAM was related to surface effects, and not to microstructural changes or occurring cracks within the bulk volume. Additionally, the source location analysis indicated, that despite lower activity in SC, we observed some clustering of the events. In contrast, in AAM, the activity inside the specimen is randomly distributed over the whole volume. The monitoring results help to estimate the material’s sealing properties which are crucial to assess their applicability as sealing material for engineered barriers.
T2 - 11th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam, Germany
DA - 11.06.2024
KW - Endlager
KW - Barriere
KW - AAM
KW - Akustische Emission
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604699
UR - https://www.ndt.net/article/ewshm2024/papers/768_manuscript.pdf
DO - https://doi.org/10.58286/29834
SN - 1435-4934
SP - 1
EP - 7
PB - NDT.net
AN - OPUS4-60469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maack, Stefan
A1 - Küttenbaum, Stefan
A1 - Niederleithinger, Ernst
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Baulicher IST-Zustand zur Bewertung von Betonbrücken auf der Grundlage messtechnischer Kennwerte - ZfPStatik
N2 - Das Projekt „ZfPStatik“ entwickelt eine Handlungsempfehlung zur Bewertung bestehender Bauwerke mit Hilfe zerstörungsfreier Messdaten. Durch die Bauwerksprüfungen können Unsicherheiten bei der Nachrechnung reduziert werden, wodurch realistischere Beurteilungen der Standsicherheit und Gebrauchstauglichkeit ermöglicht werden. Zudem wird die Entwicklung neuer Ingenieurdienstleistungen gefördert. Zerstörungsfreie Prüfverfahren haben insgesamt das Potential, die Entscheidungsgrundlagen für die Beurteilung und Erhaltung bestehender Bauwerke zu verbessern.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Betonbrücken
KW - ZfPStatik
KW - Bauwerksprüfungen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613290
SN - 978-3-9818564-7-7
SP - 303
EP - 308
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61329
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Castanon-Jano, Laura
A1 - Palomera-Obregon, Paula
A1 - Lázaro, Mariano
A1 - Blanco-Fernandez, Elena
A1 - Blasón Gonzalez, Sergio
T1 - Enhancing sustainability in polymer 3D printing via fusion filament fabrication through integration of by-products in powder form: Mechanical and thermal characterization
N2 - FFF (fused filament fabrication) is a type of 3D printing that utilizes filament for part creation. This study proposes using by-products or waste to replace part of the plastic in FFF filament, reducing environmental impact. The aim is to maintain a simple manufacturing process involving extrusion on a single-screw desktop machine followed by printing. The plastic matrix comprises polylactic acid (PLA) and polyethylene glycol (PETG), with added powdered by-products: seashells, car glass and mill scale (metal). Additives will be incorporated at 10% and 20% by weight, with two grain sizes: up to 0.09 mm and up to 0.018 mm. Mechanical tests (tensile, flexural and hardness) and thermal characterization tests will be conducted. Findings suggest adding 10%w powder of any variety to PETG increases tensile strength up to 48%, with metal powder (mill scale) showing the highest enhancement, even at 20%w, resulting in a 41% increase. Conversely, adding powder to PLA worsens mechanical properties without stiffening the material; instead, the elastic modulus decreases. Metal grain size has minimal impact, with grain sizes lower than 0.09 mm optimal for PLA. Thermal conductivity in polymers blended with powder additives is lower than in virgin polymers, likely due to air void formation, supported by density and microscopic evaluations. This research underscores the potential of utilizing waste materials with a simple FFF filament production to enhance sustainability in 3D printing practices.
KW - 3D printing
KW - FFF
KW - PLA
KW - PETg
KW - Metal powder
KW - Glass powder
KW - Seashells powder
KW - Tension
KW - Bending
KW - Thermal properties
KW - Sustainability
KW - Plastic consumption
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635027
DO - https://doi.org/10.1007/s00170-024-13635-3
SN - 0268-3768
VL - 133
IS - 3-4
SP - 1251
EP - 1269
PB - Springer
CY - London
AN - OPUS4-63502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monavari, Mahshid
A1 - Sohrabi, Razieh
A1 - Motasadizadeh, Hamidreza
A1 - Monavari, Mehran
A1 - Fatahi, Yousef
A1 - Ejarestaghi, Negin Mousavi
A1 - Fuentes-Chandia, Miguel
A1 - Leal-Egaña, Aldo
A1 - Akrami, Mohammad
A1 - Homaeigohar, Shahin
T1 - Levofloxacin loaded poly (ethylene oxide)-chitosan/quercetin loaded poly (D,L-lactide-co-glycolide) core-shell electrospun nanofibers for burn wound healing
N2 - This study developed a new burn wound dressing based on core-shell nanofibers that co-deliver antibiotic and antioxidant drugs. For this purpose, poly(ethylene oxide) (PEO)-chitosan (CS)/poly(D,L-lactide-co-glycolide) (PLGA) core-shell nanofibers were fabricated through co-axial electrospinning technique. Antibiotic levofloxacin (LEV) and antioxidant quercetin (QS) were incorporated into the core and shell parts of PEO-CS/PLGA nanofibers, respectively. The drugs could bond to the polymer chains through hydrogen bonding, leading to their steady release for 168 h. An in vitro drug release study showed a burst effect followed by sustained release of LEV and QS from the nanofibers due to the Fickian diffusion. The NIH 3T3 fibroblast cell viability of the drug loaded core-shell nanofibers was comparable to that in the control (tissue culture polystyrene) implying biocompatibility of the nanofibers and their cell supportive role. However, there was no significant difference in cell viability between the drug loaded and drug free core-shell nanofibers. According to in vivo experiments, PEO-CS-LEV/PLGA-QS core-shell nanofibers could accelerate the healing process of a burn wound compared to a sterile gauze. Thanks to the synergistic therapeutic effect of LEV and QS, a significantly higher wound closure rate was recorded for the drug loaded core-shell nanofibrous dressing than the drug free nanofibers and control. Conclusively, PEO-CS-LEV/PLGA-QS core-shell nanofibers were shown to be a promising wound healing material that could drive the healing cascade through local co-delivery of LEV and QS to burn wounds.
KW - Core-shell nanofiber
KW - Co-axial electrospinning
KW - Drug delivery
KW - Burn wound
KW - Wound healing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635115
DO - https://doi.org/10.3389/fbioe.2024.1352717
SN - 2296-4185
VL - 12
SP - 1
EP - 14
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-63511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kemmler, Samuel
A1 - Rettinger, Christoph
A1 - Rüde, Ulrich
A1 - Cuéllar, Pablo
A1 - Köstler, Harald
T1 - Efficiency and scalability of fully-resolved fluid-particle simulations on heterogeneous CPU-GPU architectures
N2 - Current supercomputers often have a heterogeneous architecture using both conventional Central Processing Units (CPUs) and Graphics Processing Units (GPUs). At the same time, numerical simulation tasks frequently involve multiphysics scenarios whose components run on different hardware due to multiple reasons, e.g., architectural requirements, pragmatism, etc. This leads naturally to a software design where different simulation modules are mapped to different subsystems of the heterogeneous architecture. We present a detailed performance analysis for such a hybrid four-way coupled simulation of a fully resolved particle-laden flow. The Eulerian representation of the flow utilizes GPUs, while the Lagrangian model for the particles runs on conventional CPUs. Two characteristic model situations involving dense and dilute particle systems are used as benchmark scenarios. First, a roofline model is employed to predict the node level performance and to show that the lattice-Boltzmann-based Eulerian fluid simulation reaches very good performance on a single GPU. Furthermore, the GPU-GPU communication for a large-scale Eulerian flow simulation results in only moderate slowdowns. This is due to the efficiency of the CUDA-aware MPI communication, combined with the use of communication hiding techniques. On 1024 A100 GPUs, an overall parallel efficiency of up to 71% is achieved. While the flow simulation has good performance characteristics, the integration of the stiff Lagrangian particle system requires frequent CPU-CPU communications that can become a bottleneck, especially when simulating the dense particle system. Additionally, special attention is paid to the CPU-GPU communication overhead since this is essential for coupling the particles to the flow simulation. However, thanks to our problem-aware co-partitioning, the CPU-GPU communication overhead is found to be negligible. As a lesson learned from this development, four criteria are postulated that a hybrid implementation must meet for the efficient use of heterogeneous supercomputers.
KW - Discrete element method
KW - Hybrid implementation
KW - High-performance computing
KW - Particulate flow
KW - Lattice Boltzmann method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623958
DO - https://doi.org/10.1177/10943420241313385
SN - 1741-2846
SP - 1
EP - 19
PB - SAGE Publications
AN - OPUS4-62395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zinas, Orestis
A1 - Papaioannou, Iason
A1 - Schneider, Ronald
A1 - Cuéllar, Pablo
T1 - Multivariate Gaussian Process Regression for 3D site characterization from CPT and categorical borehole data
N2 - Accurate prediction of subsurface stratigraphy and geotechnical properties, along with quantification of associated uncertainties, is essential for improving the design and assessment of geotechnical structures. Several studies have utilized indirect data from Cone Penetration Tests (CPTs) and employed statistical and Machine Learning methods to quantify the geological and geotechnical uncertainty. Incorporating direct borehole data can reduce uncertainties. This study proposes a computationally efficient multivariate Gaussian Process model that utilizes site-specific data and: (i) jointly models multiple categorical (USCS labels) and continuous CPT variables, (ii) learns a non-separable covariance structure leveraging the Linear Model of Coregionalization, and (iii) predicts a USCS based stratigraphy and CPT parameters at any location within the 3D domain. The results demonstrate that integrating geotechnical and geological data into a unified model yields more reliable predictions of subsurface stratification, enabling the parallel interpretation of both USCS classification and CPT profiles. Importantly, the model demonstrates its potential to integrate multiple variables from different sources and data types, contributing to the advancement of methodologies for the joint modeling of geotechnical, geological, and geophysical data.
KW - Geotechnical site-characterization
KW - Cone Penetration Tests
KW - Stratigraphy prediction
KW - Multivariate Gaussian process
KW - Variational inference
KW - Linear Model of Coregionalization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629456
DO - https://doi.org/10.1016/j.enggeo.2025.108052
SN - 1872-6917
VL - 352
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-62945
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cortabitarte, G.
A1 - Llavori, I.
A1 - Esnaola, J.A.
A1 - Blasón Gonzalez, Sergio
A1 - Larrañaga, M.
A1 - Larrañaga, J.
A1 - Arana, A.
A1 - Ulacia, I.
T1 - Application of the theory of critical distances for fatigue life assessment of spur gears
N2 - This study evaluates the effectiveness of the theory of critical distances (TCD) method in determining the fatigue lifetime of a spur gear. A comprehensive characterization of the material parameters necessary for critical distance calculation was performed, including the fatigue limit and crack growth threshold, as well as σ-N and ε-N curves for 16MnCr5 steel. A variety of TCD methods were applied to analyse the component, including the point method, line method, volume method, and mesh control. The results indicate that overall, the TCD method is a reliable and accurate way to predict the fatigue lifetime of spur gears. The study reveals a strong correlation between predicted and experimental crack locations and fatigue lifetime, suggesting accurate prediction using TCD and the Smith-Watson-Topper parameter. Although all TCD methods, when applied correctly, yield similar results, mesh control is the faster method and is therefore more attractive from an industrial perspective. The results of this study provide valuable insight for engineers and researchers in the field of fatigue analysis of spur gears and similar mechanical components.
KW - Spur gear
KW - Theory of critical distances (TCD)
KW - Multiaxial fatigue
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624246
DO - https://doi.org/10.1016/j.tafmec.2023.104086
SN - 0167-8442
VL - 128
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Borges de Oliveira, F.
A1 - Reuter, T.
A1 - Plotzki, David
A1 - Wohlgemuth, F.
A1 - Bartscher, M.
A1 - Bellon, Carsten
A1 - Kasperl, S.
T1 - Assessment of 2D-based tests for the qualification of simulation software for dXCT
N2 - The interest in using computer simulations of dimensional x-ray computed tomography (dXCT) for various metrological purposes—such as measurement planning, performance prediction, performance optimisation and, finally, measurement uncertainty estimation—is increasing along with the ever-growing demand for more reliable measurements with dXCT. However, before a piece of simulation software can be used for tasks related to coordinate metrology, it has to be ensured that it is able to simulate physical laws, characteristic effects and basic CT system functionalities correctly and with sufficient accuracy. In short, the software must be qualified for dimensional metrology tasks. As one part of such a qualification process, a method is presented here for determining conformity intervals of 2D tests (projection-based tests) based on 3D tests (testing based on dimensional evaluations in a reconstructed volume) for the assessment of dXCT simulation software. The method consists of varying relevant parameter values in order to verify their influence on 3D measurement results. The results of the 3D tests with varied parameter values are then transferred to the quantities tested in the 2D tests and used as the basis for determining conformity intervals. Two approaches are applied for determining whether or not a variation of a parameter value is significant: (a) statistical and (b) heuristic. Two examples are presented, each based on simulated images, which show the application of the two different approaches for determining conformity intervals for the results of the 2D tests.
KW - dXCT
KW - X-ray computed tomography
KW - Simulation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573316
DO - https://doi.org/10.1088/1361-6501/acc1f9
VL - 34
IS - 6
SP - 1
EP - 12
PB - IOP Publishing
AN - OPUS4-57331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kjaervik, Marit
A1 - Ramstedt, M.
A1 - Schwibbert, Karin
A1 - Dietrich, P. M
A1 - Unger, Wolfgang
T1 - Comparative Study of NAP-XPS and Cryo-XPS for the Investigation of Surface Chemistry of the Bacterial Cell-Envelope
N2 - Bacteria generally interact with the environment via processes involving their cell-envelope. Thus, techniques that may shed light on their surface chemistry are attractive tools for providing an understanding of bacterial interactions. One of these tools is Al Kα-excited photoelectron spectroscopy (XPS) with its estimated information depth of <10 nm. XPS-analyses of bacteria have been performed for several decades on freeze-dried specimens in order to be compatible with the vacuum in the analysis chamber of the spectrometer. A limitation of these studies has been that the freeze-drying method may collapse cell structure as well as introduce surface contaminants. However, recent developments in XPS allow for analysis of biological samples at near ambient pressure (NAP-XPS) or as frozen hydrated specimens (cryo-XPS) in vacuum. In this work, we have analyzed bacterial samples from a reference strain of the Gram-negative bacterium Pseudomonas fluorescens using both techniques. We compare the results obtained and, in general, observe good agreement between the two techniques. Furthermore, we discuss advantages and disadvantages with the two analysis approaches and the output data they provide. XPS reference data from the bacterial strain are provided, and we propose that planktonic cells of this strain (DSM 50090) are used as a reference material for surface chemical analysis of bacterial systems.
KW - P. Fluorescens
KW - Cryo XPS
KW - NAP-XPS
KW - DSM 5009
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525640
DO - https://doi.org/10.3389/fchem.2021.666161
VL - 9
SP - Article 666161
PB - Frontiers
CY - Switzerland
AN - OPUS4-52564
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Binder, F.
A1 - Bellon, Carsten
A1 - Wohlgemuth, F.
A1 - Hausotte, T.
T1 - Ein praxisnaher Leitfaden für computertomografische Untersuchungen mit der radiografischen Simulationsumgebung aRTist
N2 - Radiografische Simulationswerkzeuge wie aRTist, ScorpiusXLab, SimCT oder CIVA CT verwenden analytische Methoden und physikalische Monte-Carlo-Teilchentransportsimulationen, um die Interaktionsprozesse zwischen Röntgenstrahlung und Materie zu simulieren. Die berechneten Projektionen bilden anschließend unter Berücksichtigung einer definierten Scan-Trajektorie die Basis der Simulation einer röntgencomputertomografischen Untersuchung.
Für den erfolgreichen Einsatz der Computertomografie, sei es als zerstörungsfreie Prüfmethode oder beim dimensionellen Messen, ist es generell notwendig, bekannte Fehler- bzw. Abweichungsquellen des Messverfahrens auszuschließen oder zu reduzieren. Dabei hat sich gezeigt, dass die Auswahl der Messparameter und die Erfahrung des Anwenders direkten Einfluss auf das erzielbare Messergebnis einer computertomografischen Untersuchung nehmen. Es ist daher sinnvoll, die Parameterauswahl in einem virtuellen Simulationsaufbau vorher zu erproben und an die Messaufgabe anzupassen.
Neben der Optimierung von Messparametern finden radiografische Simulationswerkzeuge auch Anwendung für Machbarkeitsstudien und werden zur Schulung von Anwendern im Bereich der Röntgen-Computertomografie verwendet.
Radiografische Simulationswerkzeuge befinden sich in einem stetigen Wandel, beispielsweise durch die Entwicklung neuer Rekonstruktionsmethoden, durch Erweiterung von analytischen Modellen, durch Integration komplexer Trajektorien oder durch Berücksichtigung von prozessbedingten geometrischen Abweichungen. Im laufenden EMPIR-Projekt „AdvanCT“ entsteht deshalb ein „Good Practice Guide“ für die Simulationsumgebung aRTist. Ziel dieses Guides ist es, die mit steigender Komplexität verbundenen Einstiegshürden für Anwender von aRTist zu reduzieren, um damit einen praxisnahen Zugang zur virtuellen Computertomografie zu ermöglichen. Dabei werden anhand von praktisch nachvollziehbaren Beispielen die grundlegenden Mechanismen der Simulationsumgebung erklärt und ein strukturierter Leitfaden zur Simulation röntgencomputertomografischer Untersuchungen mit aRTist vermittelt.
In diesem Beitrag werden erste Auszüge des Guides sowie eine Übersicht der weiteren geplanten Themen für die anschließende Diskussion vorgestellt.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Computertomografie
KW - Simulation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530476
UR - https://jahrestagung.dgzfp.de/portals/jt2021/bb176/inhalt/poster.htm
SN - 978-3-947971-18-3
VL - 176
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-53047
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brierley, N.
A1 - Bellon, Carsten
A1 - Lazaro Toralles, B.
T1 - Optimized multi-shot imaging inspection design
N2 - The inspection of complex-shaped components, such as those enabled by additive manufacturing, is a major challenge in industrial quality assurance. A frequently adopted approach to volumetric non-destructive evaluation is X-ray computed tomography, but this has major drawbacks. Two-dimensional radiography can overcome some of these problems, but does not generally provide an inspection that is as capable.
Moreover, designing a detailed inspection for a complex-shaped component is a labour-intensive task, requiring significant expert input. In response, a computational framework for optimizing the data acquisition for an image-based inspection modality has been devised. The initial objective is to advance the capabilities of radiography, but the algorithm is, in principle, also applicable to alternative types of imaging. The algorithm exploits available prior
information about the inspection and simulations of the inspection modality to allow the Determination of the optimal inspection configuration, including specifically component poses with respect to the imaging system. As an intermediate output, spatial maps of inspection performance are computed, for understanding spatially varying limits of detection. Key areas of innovation concern the defect detectability evaluation for arbitrarily complex indications and the creation of an application-specific optimization algorithm. Initial trials of the algorithm are presented, with good results.
KW - Inspection design and planning
KW - Optimization
KW - Radiography
KW - Simulation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458363
DO - https://doi.org/10.1098/rspa.2017.0319
SN - 1471-2946
SN - 1364-5021
VL - 474
IS - 2216
SP - 70319, 1
EP - 25
PB - The Royal Society
CY - London
AN - OPUS4-45836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Anja
A1 - Buchberger, G.
A1 - Stifter, D.
A1 - Duchoslav, J.
A1 - Hertwig, Andreas
A1 - Bonse, Jörn
A1 - Heitz, J.
A1 - Schwibbert, Karin
T1 - Spatial Period of Laser-Induced Surface Nanoripples on PET Determines Escherichia coli Repellence
N2 - Bacterial adhesion and biofilm formation on surfaces are associated with persistent microbial contamination, biofouling, and the emergence of resistance, thus, calling for new strategies to impede bacterial surface colonization. Using ns-UV laser treatment (wavelength 248 nm and a pulse duration of 20 ns), laser-induced periodic surface structures (LIPSS) featuring different submicrometric periods ranging from ~210 to ~610 nm were processed on commercial poly(ethylene terephthalate) (PET) foils. Bacterial adhesion tests revealed that these nanorippled surfaces exhibit a repellence for E. coli that decisively depends on the spatial periods of the LIPSS with the strongest reduction (~91%) in cell adhesion observed for LIPSS periods of 214 nm. Although chemical and structural analyses indicated a moderate laser-induced surface oxidation, a significant influence on the bacterial adhesion was ruled out. Scanning electron microscopy and additional biofilm studies
using a pili-deficient E. coli TG1 strain revealed the role of extracellular appendages in the bacterial repellence observed here.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser processing
KW - Polyethylene terephthalate
KW - Biofilm formation
KW - Cell appendages
KW - Biomimetic
KW - F pili
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537431
DO - https://doi.org/10.3390/nano11113000
VL - 11
IS - 11
SP - 3000
PB - MDPI
AN - OPUS4-53743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Deresch, Andreas
A1 - Jaenisch, Gerd-Rüdiger
A1 - Bellon, Carsten
T1 - A fast general spectrum model for quantitative radiography simulation
N2 - One essential step on the way towards accurate quantitative simulation of radiographic testing is an accurate description of the utilized energy spectrum of X-ray photons. For use in general purpose simulation tools, the spectra of X-ray tubes have to be described by a model covering at least the intended range of applications. This range includes transmission tubes as well as direct beam tubes with varying angles of incidence and emission, for a number of typical target materials. In radiographic testing acceleration voltages frequently reach up to 450 kV for direct beam targets and up to 225 kV for transmission targets, with even higher voltages available or being developed. Currently used models are unable to cover the whole range of configurations.
Here a model is presented that employs a unified approach for simulating the photon energy spectra for transmission and direct beam targets composed of arbi-trary homogeneous materials. In order to achieve this, a detailed model of electron transport within the target is employed. The validity of the developed model is shown through comparisons with Monte Carlo simulations as well as measurements for a number of different configurations.
T2 - 19th World Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Measurements
KW - X-ray spectra
KW - Simulation
KW - Electron transport
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365959
SN - 978-3-940283-78-8
VL - 158
SP - 1
EP - 7
PB - DGZfP
CY - Berlin, Germany
AN - OPUS4-36595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bellon, Carsten
A1 - Zhukovskiy, M.
A1 - Markov, M.
A1 - Podolyako, S.
A1 - Uskov, R.
A1 - Jaenisch, Gerd-Rüdiger
T1 - Supercomputing the cascade processes of radiation transport
N2 - Modeling of the photon-electron cascade progress in multicomponent objects of complex geometrical structure by use of hybrid supercomputers is considered. An approach to computing the cascade processes is developed. The approach has three key properties allowing the effective use of heterogeneous structure of computers for solving the tasks of radiation transport in complex multi-scale geometries. Firstly, two different discreet geometrical description of an object being under radiation is used: triangulated model for photon transport and voxel model for electron transport. Secondly, small parameter of the problem is explicitly taking into account for modeling surface effects (for instance, electron emission). Thirdly, the effective calculation decomposition between CPU and GPU is developed for significant increasing the speed of calculations of processes in question. Modeling of experiment on researching the bremsstrahlung generated by electron beam in Ta target is carried out. Comparison of computing and experimental results shows satisfactory consent.
T2 - 19th World Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Super somputing
KW - Photon-electron transport
KW - Monte Carlo methods
KW - Modelling
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365932
SN - 978-3-940283-78-8
VL - 158
SP - 1
EP - 6
PB - DGZfP
CY - Berlin, Germany
AN - OPUS4-36593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kjaervik, Marit
A1 - Schwibbert, Karin
A1 - Dietrich, P.
A1 - Thissen, A.
A1 - Unger, Wolfgang
T1 - Surface characterisation of Escherichia coli under various conditions by near-ambient pressure XPS
N2 - Bacteria are inherently in a hydrated state and therefore not compatible to ultra-high vacuum techniques such as XPS without prior sample preparation involving freeze drying or fast freezing.
This has changed with the development of near-ambient pressure (NAP)-XPS, which makes it possible to characterise the bacterial surface with minimal sample preparation. This paper presents NAP-XPS measurements of Escherichia coli under various NAP conditions: at 11 mbar in a humid environment, at 2 mbar after drying in the chamber, pre-dried at 4 mbar, and at 1 mbar after overnight pumping at 10^−4 mbar. The high-resolution spectra of carbon, nitrogen, and oxygen are presented and found to be in general agreement with XPS measurements from freeze-dried and fast-frozen bacteria. However, it was found that the amount of carbon components associated with polysaccharides increases relative to aliphatic carbon during drying and increases further after overnight pumping. This implies that drying has an impact on the bacterial surface.
T2 - European conference on applications of surface and interface analysis (ECASIA'17)
CY - Montpellier, France
DA - 24.09.2018
KW - Bacteria
KW - E. coli
KW - NAP-XPS
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454047
DO - https://doi.org/10.1002/sia.6480
SN - 0142-2421
SN - 1096-9918
VL - 50
IS - 11
SP - 996
EP - 1000
PB - John Wiley & Sons
CY - Hoboken, New Jersey, USA
AN - OPUS4-45404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Binder, F.
A1 - Bircher, B.
A1 - Laquai, René
A1 - Küng, A.
A1 - Bellon, Carsten
A1 - Meli, F.
A1 - Deresch, A.
A1 - Ulrich Neuschaefer-Rube, U.
A1 - Hausotte, T.
T1 - Methodologies for model parameterization of virtual CTs for measurement uncertainty estimation
N2 - X-ray computed tomography (XCT) is a fast-growing technology for dimensional measurements in industrial applications. However, traceable and efficient methods to determine measurement uncertainties are not available. Guidelines like the VDI/VDE 2630 Part 2.1 suggest at least 20 repetitions of a specific measurement task, which is not feasible for industrial standards. Simulation-based approaches to determine task specific measurement uncertainties are promising, but require closely adjusted model parameters and an integration of error sources like geometrical deviations during a measurement. Unfortunately, the development of an automated process to parameterize and integrate geometrical deviations into XCT models is still an open issue. In this work, the whole processing chain of dimensional XCT measurements is taken into account with focus on the issues and requirements to determine suitable parameters of geometrical deviations. Starting off with baseline simulations of different XCT systems, two approaches are investigated to determine and integrate geometrical deviations of reference measurements. The first approach tries to iteratively estimate geometric deviation parameter values to match the characteristics of the missing error sources. The second approach estimates those values based on radiographs of a known calibrated reference object. In contrast to prior work both approaches only use a condensed set of parameters to map geometric deviations. In case of the iterative approach, some major issues regarding unhandled directional dependencies have been identified and discussed. Whereas the radiographic method resulted in task specific expanded measurements uncertainties below one micrometre even for bi-directional features, which is a step closer towards a true digital twin for uncertainty estimations in dimensional XCT.
KW - Geometrical deviation
KW - X-ray computed tomography
KW - Uncertainty estimation
KW - Virtual CT
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553263
DO - https://doi.org/10.1088/1361-6501/ac7b6a
VL - 33
IS - 10
SP - 1
EP - 15
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-55326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neuschaefer-Rube, U.
A1 - Illemann, J.
A1 - Sturm, M.
A1 - Bircher, B.
A1 - Meli, F.
A1 - Bellon, Carsten
A1 - Evsevleev, Sergei
T1 - Validation of a fast and traceable radiographic scale calibration of dimensional computed tomography
N2 - A fast and highly precise method of determining the geometrical scale factor of computed tomography (CT) measurements has been validated successfully by Bundesanstalt für Materialforschung und -prüfung (BAM), the Federal Institute of Metrology (METAS) and Physikalisch-Technische Bundesanstalt (PTB) within the scope of AdvanCT (Advanced Computed Tomography for dimensional and surface measurements in industry), a project funded in the European Metrology Programme for Innovation and Research (EMPIR). The method has been developed by PTB and requires only two radiographic images of a calibrated thin 2D standard (hole grid standard) from two opposite directions. The mean grid distance is determined from both radiographs. From this and with the help of the calibration result, the radiographic scale and therefore the voxel size is determined. The procedure takes only a few minutes and avoids a time-consuming CT scan. To validate the method, the voxel sizes determined via this method were compared with voxel sizes determined from CT scans of calibrated objects. Relative deviations between the voxel sizes in the range of 10−5 were
achieved with minimal effort using cone-beam CT systems at moderate magnifications.
KW - Dimensional metrology
KW - Voxel size
KW - Industrial CT
KW - Geometrical magnification
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553271
DO - https://doi.org/10.1088/1361-6501/ac74a3
SN - 0957-0233
VL - 33
IS - 9
SP - 1
EP - 9
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-55327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritsch, Tobias
A1 - Kurpiers, J.
A1 - Roland, S.
A1 - Tokmoldin, N.
A1 - Shoaee, S.
A1 - Ferron, T.
A1 - Collins, B. A.
A1 - Janietz, S.
A1 - Vandewal, K.
A1 - Fritsch, D.
T1 - On the Interplay between CT and Singlet Exciton Emission in Organic Solar Cells with Small Driving Force and Its Impact on Voltage Loss
N2 - The interplay between free charge carriers, charge transfer (CT) states and singlet excitons (S1) determines the recombination pathway and the resulting open circuit voltage (VOC) of organic solar cells. By combining a well-aggregated low bandgap polymer with different blend ratios of the fullerenes PCBM and ICBA, the energy of the CT state (ECT) is varied by 130 meV while leaving the S1 energy of the polymer (ES1) unaffected. It is found that the polymer exciton dominates the radiative properties of the blend when ECT approaches ES1, while the VOC remains limited by the non-radiative decay of the CT state. It is concluded that an increasing strength of the exciton in the optical spectra of organic solar cells will generally decrease the non-radiative voltage loss because it lowers the radiative VOC limit (VOC,rad), but not because it is more emissive. The analysis further suggests that electronic coupling between the CT state and the S1 will not improve the VOC, but rather reduce the VOC,rad. It is anticipated that only at very low CT state absorption combined with a fairly high CT radiative efficiency the solar cell benefit from the radiative properties of the singlet excitons.
KW - Organic Solar Cell
KW - Open Circuit Voltage
KW - Voltage Loss
KW - Ternary
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552518
DO - https://doi.org/10.1002/aenm.202200641
SN - 1614-6832
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernardy, Christopher
A1 - Habib, Abdel Karim
A1 - Kluge, Martin
A1 - Schalau, Bernd
A1 - Kant, Hanjo
A1 - Schulze, Marcel
A1 - Orchini, Alessandro
T1 - Large-scale investigations of the thermal radiation of hydrogen jet flames
N2 - For industrial applications dealing with hydrogen, the definition of safety distances and the assessment of possible hazards emanating from releases is mandatory. Since hydrogen is usually stored and transported under pressure, one scenario to be considered is the momentum driven release of hydrogen from a leakage with subsequent ignition. In this scenario, the emitted heat radiation from the resulting jet flame to the surroundings has to be determined to define adequate safety distances. For hydrocarbon flames, different jet flame models are available to assess the hazards resulting from an ignited jet release. Since hydrogen flames differ from hydrocarbon flames in their combustion behavior, it has to be checked if these models are also applicable for hydrogen.
To evaluate the accuracy of these models for hydrogen jet flames, tests with a horizontal outlet at large-scale are carried out at the BAM Test Site for Technical Safety (BAM-TTS). Herein, the flame geometry and the heat radiation at defined locations in the surroundings are recorded for varying release parameters such as release pressure (currently up to max. 250 bar), mass flow (up to max. 0.175 kg/s) at an outlet diameter of 30 mm (with an upstream nozzle of 7.7 mm). The challenge here is the characterization of the flame geometry in an open environment and its impact on the thermal radiation. Existing heat radiation data from the literature are mostly based on unsteady outflow conditions. For a better comparability with the steady state jet flame models, the experiments presented here are focused on ensuring a constant mass flow over the release duration (currently 120 s) to obtain a stationary jet flame. In addition, stationary outflow tests with hydrocarbons (methane) were also carried out, which are intended to serve as reference tests for checking flame models based on hydrocarbon data. The comparison of the flame geometry shows that hydrogen jet flames with the same outlet mass flow have a greater flame length (average deviation of 15 %) but a smaller flame diameter than methane jet flames (average deviation of 17 %). Conclusions regarding thermal radiation show that the proportion of total combustion energy emitted as thermal radiation is lower for hydrogen (x_rad= 0.04–0.09) than for methane (x_rad = 0.06–0.1). A comparison of the surface emissive power (SEP) of the jet flame shows a SEP range of 7 kW/m2-15 kW/m2 for hydrogen and 3 kW/m2 - 9,5 kW/m2 for methane.
KW - Hydrogen
KW - Release
KW - Thermal radiation
KW - Jet flame
KW - Radiant heat fraction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622891
DO - https://doi.org/10.1016/j.jlp.2024.105491
SN - 1873-3352
VL - 94
SP - 1
EP - 6
PB - Elsevier B.V.
AN - OPUS4-62289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schalau, Sebastian
A1 - Habib, Abdel Karim
A1 - Michel, S.
T1 - A modified k-ε turbulence model for heavy gas dispersion in built-up environment
N2 - For hazard assessment purposes, the dispersion of gases in complex urban areas is often a scenario to be considered. However, predicting the dispersion of heavy gases is still a challenge. In Germany, the VDI Guideline 3783, Part 1 and 2 is widely used for gas dispersion modelling. Whilst Part 1 uses a gauss model for calculating the dispersion of light or neutrally buoyant gases, Part 2 uses wind tunnel experiments to evaluate the heavier-than-air gas dispersion in generic built up areas. In practice, with this guideline, it is often not possible to adequately represent the existing obstacle configuration. To overcome this limitation, computational fluid dynamics (CFD) methods could be used. Whilst CFD models can represent obstacles in the dispersion area correctly, actual publications show that there is still further research needed to simulate the atmospheric flow and the heavy gas dispersion. This paper presents a modified k-ε-turbulence model that was developed in OpenFOAM v5.0 (England, London, The OpenFOAM Foundation Ltd Incorporated) to enhance the simulation of the atmospheric wind field and the heavy gas dispersion in built-up areas. Wind tunnel measurements for the dispersion of neutrally buoyant and heavy gases in built-up environments were used to evaluate the model. As a result, requirements for the simulation of the gas dispersion under atmospheric conditions have been identified and the model showed an overall good performance in predicting the experimental values.
KW - Atmospheric boundary layer
KW - OpenFOAM
KW - Heavy gas
KW - CFD
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568898
DO - https://doi.org/10.3390/atmos14010161
VL - 14
IS - 1
SP - 1
EP - 21
PB - MDPI
AN - OPUS4-56889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Delgado Arroyo, Diego
A1 - Börner, Andreas
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Lindner, T.
A1 - Löbel, M.
A1 - Preuß, B.
A1 - Lampke, T.
T1 - Ultrasonic assisted milling of a CoCrFeNi medium entropy alloy
N2 - Medium and High Entropy Alloys (MEA/HEA) are recently developed material classes, providing manifold applications, e.g., due to extraordinary structural properties. In that connection, the machinability as important issue for the processing of these materials was not in the scientific focus. This study focusses on experimental analysis of milling process conditions including ultrasonic assisted milling (USAM) and their effects on the resulting surface integrity of equiatomic CoCrFeNi-MEA specimens. For that reason, milling parameters (cutting speed, feed per cutting edge) were systematically varied for both conventional milling and USAM. The surface integrity was analyzed in terms of topography, defects, and residual stresses. Especially USAM leads to a decrease of occurring cutting forces and, hence, to an improvement of the surface integrity. Beneficial effects were observed in terms of lower tensile residual stresses at high cutting speed and feed per cutting edge.
KW - Medium entropy alloy
KW - Ultrasonic Assisted Machining
KW - Surface Integrity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554458
DO - https://doi.org/10.1016/j.procir.2022.05.203
VL - 108
SP - 879
EP - 884
PB - Elsevier B.V.
AN - OPUS4-55445
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dorgerloh, Ute
A1 - Becker, Roland
A1 - Freeling, Finnian
A1 - Scheurer, Marco
A1 - Gökçe, Emine
A1 - Strack, Katrin
A1 - Sommerfeld, Thomas
A1 - Sauer, Andreas
A1 - Schneider, Jonas
A1 - Härtel, Christoph
A1 - Valkov, Vassil
A1 - Moser, Lukas
A1 - Geiß, Sabine
A1 - Junginger, Sabine
A1 - Schlittenbauer, Linda
A1 - Suess, Elke
A1 - Ruth, Katinka
T1 - Standardising the quantification of trifluoroacetic acid in water: Interlaboratory validation trial using liquid chromatography-mass spectrometric detection (LC–MS/MS)
N2 - The concentration of trifluoroacetic acid in surface and groundwaters and drinking water is subject of increasing concern. Since there is no standardised procedure available, German standardisation body DIN has initiated the first draft standard using liquid chromatography with tandem mass spectrometry (LC–MS/MS) after direct injection for the concentration range between ≥ 0.1 and 3 µg/L. Herein, the interlaboratory comparison as final validation step involving 12 expert laboratories from Germany and Switzerland is described. Two groundwaters, two surface waters, a drinking water, a rainwater, and two fortified groundwater samples displayed relative repeatability standard deviations between 3 and 7% and relative reproducibility standard deviation between 6 and 20% and were included in the draft standard DIN 38407-53.
KW - TFA Trifluoroacetic acid
KW - LC/MS-MS
KW - Validation trial
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632376
DO - https://doi.org/10.1007/s00769-025-01640-2
SN - 0949-1775
SP - 1
EP - 4
PB - Springer
CY - Berlin
AN - OPUS4-63237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valet, Svenja
A1 - Burkert, Andreas
A1 - Ebell, Gino
A1 - Babutzka, Martin
T1 - Determination of the corrosion product layer resistance on zinc and electrolytically galvanized steel samples by using gel electrolytes
N2 - Although zinc and zinc coatings have been widely used for corrosion protection for decades new zinc coatings are constantly being developed. Characterizing the corrosion protectiveness of these new coatings, however, should not be underestimated. While exposure tests are time intensive, cyclic tests can only be used for a very limited field of application. Thus, electrochemical measurements provide both an efficient and an effective alternative. Conventional aqueous bulk electrolytes influence the surface layers of a tested zinc coating and are therefore not reliable. Gel electrolytes, however, have evolved over the last few years, are minimally invasive and provide reliable results.
This work describes experiments with gel electrolytes made of agar. Unlike previous work, it proposes a composition of gel electrolyte for minimally invasive description of the protective power of naturally formed oxide layers on zinc and zinc coatings. Therefore, as a first part, the gel electrolyte made of agar is verified as a method for zinc and zinc-coated samples. Afterwards, this paper introduces the corrosion product layer resistance RL as a promising parameter to evaluate the protective power of zinc coatings. Results are verified with EIS and FTIR measurements. An example on a representative zinc coating demonstrates the practical application.
KW - Gel electrolytes
KW - Agar
KW - Zinc coatings
KW - Atmospheric exposure
KW - Corrosion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526053
DO - https://doi.org/10.1016/j.electacta.2021.138191
SN - 0013-4686
VL - 385
SP - 138191
PB - Elsevier Ltd.
AN - OPUS4-52605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilhelm, Eugen
A1 - Mente, Tobias
A1 - Rhode, Michael
T1 - Waiting time before NDT of welded offshore steel grades under consideration of delayed hydrogen-assisted cracking
N2 - Offshore wind turbines (OWT) are a major goal of the energy strategy of Germany encompassing the increase of the installed wind power. OWT components are manufactured from welded steel plates with thicknesses up to 200 mm. The underlying standards and technical recommendations for construction of OWTs encompass specifications of so-called minimum waiting time (MWT) before non-destructive testing of the weld joints is allowed. Reason is the increased risk of time-delayed hydrogen assisted cold cracking as hydrogen diffusion is very slow due to the very thick plates. The strict consideration of those long MWT up to 48 h during the construction of OWTs leads to significant financial burden (like disproportionately high costs for installer ships as well as storage problems (onshore)). In this study, weld joints made of S355 ML were examined in comparison with the offshore steel grade S460 G2+M. The aim was to optimize, i.e., reduce, the MWT before NDT considering varied heat input, hydrogen concentration and using self-restraint weld tests. This would significantly reduce the manufacturing time and costs of OWT construction. To quantify the necessary delay time until hydrogen-assisted cold cracks appear, acoustic emission analysis was applied directly after welding for at least 48 h.
KW - Hydrogen
KW - Welding
KW - Cracking
KW - Offshore
KW - Steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524959
DO - https://doi.org/10.1007/s40194-020-01060-5
SN - 0043-2288
VL - 65
SP - 947
EP - 959
PB - Springer Nature
AN - OPUS4-52495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rhode, Michael
A1 - Wetzel, Annica
A1 - Oczan, Ozlem
A1 - Nietzke, Jonathan
A1 - Richter, Tim
A1 - Schröpfer, Dirk
T1 - Corrigendum: Hydrogen diffusion and local Volta potential in high- and medium-entropy alloys (2020 IOP Conf. Ser.: Mater. Sci. Eng. 882 012015)
N2 - In the sub-section “2.1 Investigated materials” the chemical composition of Co, Cr and Mn was in wrong order for both HEA and MEA. The content of table 1 is here included in the correct version.
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527050
DO - https://doi.org/10.1088/1757-899X/882/1/012027
VL - 882
SP - 1
EP - 2
PB - IOP Publishing
CY - Bristol
AN - OPUS4-52705
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Erxleben, Kjell
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Mente, Tobias
A1 - Michael, Thomas
T1 - Local mechanical properties of dissimilar metal TIG welded joints of CoCrFeMnNi high entropy alloy and AISI 304 austenitic steel
N2 - Multiple principal element alloys encompass the well-known high entropy alloys (HEA). The alloy system represents a new class of materials consisting of at least three alloying elements, each containing 5 to 35 at.%. Thus, this alloying concept differs fundamentally from conventional materials such as steel or nickel alloys. For this purpose, the alloying elements are specifically selected, the microstructures are adjusted in a single-phase and, in some cases, multi-phase manner. In particular, conflicting goals, such as the trade-off between strength and ductility in conventional steels, are overcome. However, in the last 20 years, the focus has been on material synthesis. With the increase in available material quantities, the focus is now on processing issues such as joining and welding processes. The weldability of HEAs has received very little attention so far. The experience with dissimilar metal welds is completely lacking but is essential for the application of these materials in combination with conventional materials. The present study presents comprehensive experimental results on the weldability of an equimolar CoCrFeMnNi-HEA in cold-rolled and heat-treated condition, which was joined by tungsten inert gas welding to an austenitic steel AISI 304. The mechanical properties of the dissimilar metal welds were characterized by cross-weld tensile samples, whereas the local deformation in the weld of the different welding zones was measured by digital image correlation. In accordance with the respective initial HEA condition (cold-rolled vs. heat-treated), the local strain behavior was divergent and influenced the global mechanical properties of both DMW types. Nonetheless, the experiments provided proof in principle of the weldability for dissimilar joints of the CoCrFeMnNi-HEA welded to conventional materials like austenitic stainless steels ensuring a corresponding capability for mechanical loading. This allows further considerations on the application of these innovative materials.
KW - TIG welding
KW - High-entropy alloys
KW - Mechanical properties
KW - Dissimilar metal weld
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595775
DO - https://doi.org/10.1007/s40194-024-01718-4
SN - 0043-2288
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-59577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Giese, Marcel
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Michael, Thomas
A1 - Fritsch, Tobias
T1 - Influence of Surface Preparation on Cracking Phenomena in TIG-Welded High and Medium Entropy Alloys
N2 - Multi-element systems with defined entropy (HEA—high entropy alloy or MEA—medium entropy alloy) are rather new material concepts that are becoming increasingly important in materials research and development. Some HEA systems show significantly improved properties or combinations of properties, e.g., the overcoming of the trade-off between high strength and ductility. Thus, the synthesis, the resulting microstructures, and properties of HEA have been primarily investigated so far. In addition, processing is crucial to achieve a transfer of potential HEA/MEA materials to real applications, e.g., highly stressed components. Since fusion welding is the most important joining process for metals, it is of vital importance to investigate the weldability of these materials. However, this has rarely been the subject of research to date. For that reason, in this work, the weldability depending on the surface preparation of a CoCrFeMnNi HEA and a CoCrNi MEA for TIG welding is investigated. The fusion welding of longer plates is described here for the first time for the CoCrNi alloy. The welds of both materials showed distinct formation of cracks in the heat affected Zone (HAZ). Optical and scanning electron microscopy analysis clearly confirmed an intergranular fracture topography. However, based on the results, the crack mechanism cannot be conclusively identified as either a liquid metal embrittlement (LME) or hot cracking-like liquid film separation.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - TIG welding
KW - Cracking
KW - High entropy alloy
KW - Medium entropy alloy
KW - Surface preparation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541697
DO - https://doi.org/10.3390/jmmp6010005
SN - 2504-4494
VL - 6
IS - 5
SP - 1
EP - 13
PB - MDPI
CY - Basel (CH)
AN - OPUS4-54169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schalau, Sebastian
A1 - Habib, Abdel Karim
T1 - Atmospheric wind field modelling with OpenFOAM for near-ground gas dispersion
N2 - CFD simulations of near-ground gas dispersion depend significantly on the accuracy of the wind field. When simulating wind fields with conventional RANS turbulence models, the velocity and turbulence profiles specified as inlet boundary conditions change rapidly in the approach flow region. As a result, when hazardous materials are released, the extent of hazardous areas is calculated based on an approach flow that differs significantly from the boundary conditions defined. To solve this problem, a turbulence model with consistent boundary conditions was developed to ensure a horizontally homogeneous approach flow. Instead of the logarithmic vertical velocity profile, a power law is used to overcome the problem that with the logarithmic profile, negative velocities would be calculated for heights within the roughness length. With this, the problem that the distance of the wall-adjacent cell midpoint has to be higher than the roughness length is solved, so that a high grid resolution can be ensured even in the near-ground region which is required to simulate
gas dispersion. The evaluation of the developed CFD model using the German guideline VDI 3783/9 and wind tunnel experiments with realistic obstacle configurations showed a good agreement between the calculated and the measured values and the ability to achieve a horizontally homogenous approach flow.
KW - OpenFOAM
KW - Gas dispersion
KW - Atmospheric boundary layer
KW - Turbulence model
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539095
DO - https://doi.org/10.3390/atmos12080933
VL - 12
IS - 8
SP - 933
PB - MDPI
AN - OPUS4-53909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - D'Accardi, E.
A1 - Krankenhagen, Rainer
A1 - Ulbricht, Alexander
A1 - Pelkner, Matthias
A1 - Pohl, Rainer
A1 - Palumbo, D.
A1 - Galietti, U.
T1 - Capability to detect and localize typical defects of laser powder bed fusion (L‑PBF) process: an experimental investigation with different non‑destructive techniques
N2 - Additive manufacturing (AM) technologies, generally called 3D printing, are widely used because their use provides a high added value in manufacturing complex-shaped components and objects. Defects may occur within the components at different time of manufacturing, and in this regard, non-destructive techniques (NDT) represent a key tool for the quality control of AM components in many industrial fields, such as aerospace, oil and gas, and power industries. In this work, the capability of active thermography and eddy current techniques to detect real imposed defects that are representative of the laser powder bed fusion process has been investigated. A 3D complex shape of defects was revealed by a μCT investigation used as reference results for the other NDT methods. The study was focused on two different types of defects: porosities generated in keyhole mode as well as in lack of fusion mode. Different thermographic and eddy current measurements were carried out on AM samples, providing the capability to detect volumetric irregularly shaped defects using non-destructive methods.
KW - Additive Manufacturing
KW - Defect detection
KW - Thermography
KW - Eddy-current testing
KW - Micro-computed tomography
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546680
DO - https://doi.org/10.1007/s40964-022-00297-4
SN - 2363-9512
VL - 7
IS - 6
SP - 1239
EP - 1256
PB - Springer
AN - OPUS4-54668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Franchin, G.
A1 - Zocca, Andrea
A1 - Karl, D.
A1 - Yun, H.
A1 - Tian, X.
T1 - Editorial: Advances in additive manufacturing of ceramics
N2 - Recently, additive manufacturing of ceramics has achieved the maturity to be transferred from scientific laboratories to industrial applications. At the same time, research is progressing to expand the boundaries of this field into the territory of novel materials and applications. This feature issue addresses current progress in all aspects of additive manufacturing of ceramics, from parts design to feedstock selection, from technological development to characterization of printed components.
KW - Additive manufacturing
KW - Ceramic
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549361
DO - https://doi.org/10.1016/j.oceram.2022.100277
SN - 2666-5395
VL - 10
SP - 1
EP - 2
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Salari, Farid
A1 - Zocca, Andrea
A1 - Bosetti, Paolo
A1 - Hlaváček, Petr
A1 - Italiano, Antonino
A1 - Gobbin, Filippo
A1 - Colombo, Paolo
A1 - Kühne, Hans-Carsten
A1 - Sglavo, Vincenzo M.
T1 - Powder-bed 3D printing by selective activation of magnesium phosphate cement: Determining significant processing parameters and their effect on mechanical strength
N2 - The present work addresses powder bed binder jetting additive manufacturing by selective magnesium phosphate cement activation. Despite the potential of this technology to aid the digitalization of the construction industry, the effect of processing parameters on the mechanical performance of printed materials has not yet been studied to generate a guideline for the further development of the technology. Statistical methodologies were used to screen the effect of four printing process parameters (printing speed, layer thickness, raster angle, and build direction on flexural and compressive strength). As the exploited technology works with constant fluid pressure, the physical interpretation of the effect of each factor can be considered taking into account the interactions between the binder materials in the powder bed. Analysis of variance (ANOVA) indicated that printing speed and layer thickness significantly affect mechanical performances. Furthermore, the layout of samples for the printing process is preferable to be parallel the printhead movement. An anisotropic behavior was observed, and the samples subjected to compressive forces parallel to the layer plane possessed lower strength values. This effect can be interpreted as a result of a weak area of low density in between layers, leading to a pronounced delamination under compression. Even though the strength of the printed material is not suitable for a structural concrete, it can be marginally improved by design of experiment and optimized for non-structural applications, such as for porous artificial stone. Design of experiment coupled with ANOVA methods can be used in the future to support the development of novel material mixtures, thus expanding the fields of application of this novel additive manufacturing technology.
KW - Concrete 3D-printing
KW - Particle-bed binder jetting
KW - Design of experiment
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601654
DO - https://doi.org/10.1016/j.oceram.2024.100609
VL - 18
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-60165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Foroutan, F.
A1 - Kyffin, B. A.
A1 - Nikolaou, A.
A1 - Merino-Gutierrez, J.
A1 - Abrahams, I.
A1 - Kanwal, N.
A1 - Knowles, J. C.
A1 - Smith, A. J.
A1 - Smales, Glen Jacob
A1 - Carta, D.
T1 - Highly porous phosphate-based glasses for controlled delivery of antibacterial Cu ions prepared via sol–gel chemistry
N2 - Mesoporous glasses are a promising class of bioresorbable biomaterials characterized by high surface area and extended porosity in the range of 2 to 50 nm. These peculiar properties make them ideal materials for the controlled release of therapeutic ions and molecules. Whilst mesoporous silicate-based glasses (MSG) have been widely investigated, much less work has been done on mesoporous phosphate-based glasses (MPG). In the present study, MPG in the P2O5–CaO–Na2O system, undoped and doped with 1, 3, and 5 mol% of Cu ions were synthesized via a combination of the sol–gel method and supramolecular templating. The non-ionic triblock copolymer Pluronic P123 was used as a templating agent. The porous structure was studied via a combination of Scanning Electron Microscopy (SEM), Small-Angle X-ray Scattering (SAXS), and N2 adsorption–desorption analysis at 77 K. The structure of the phosphate network was investigated via solid state 31P Magic Angle Spinning Nuclear Magnetic Resonance (31P MAS-NMR) and Fourier Transform Infrared (FTIR) spectroscopy. Degradation studies, performed in water via Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES), showed that phosphates, Ca2+, Na+ and Cu ions are released in a controlled manner over a 7 days period. The controlled release of Cu, proportional to the copper loading, imbues antibacterial properties to MPG. A significant statistical reduction of Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli) bacterial viability was observed over a 3 days period. E. coli appeared to be more resistant than S. aureus to the antibacterial effect of copper. This study shows that copper doped MPG have great potential as bioresorbable materials for controlled delivery of antibacterial ions.
KW - Bioresorbable Biomaterials
KW - Mesoporous phosphate-based glasses
KW - Synthesis
KW - Degradation studies
KW - X-ray scattering
KW - MOUSE
KW - Antibacterial properties
KW - Aantimicrobial
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578101
DO - https://doi.org/10.1039/D3RA02958A
VL - 13
IS - 29
SP - 19662
EP - 19673
PB - Royal Society of Chemistry
AN - OPUS4-57810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, W.
A1 - Schweins, R.
A1 - Nöcker, B.
A1 - Kohlbrecher, J.
A1 - Smales, Glen Jacob
A1 - Huber, K.
T1 - Comparative study of the co-assembly behaviour of 3-chloro-4-hydroxy-phenylazo dyes with DTAB
N2 - The co-assembly of three one-fold negatively charged 3-chloro-4-hydroxy-phenylazo dyes (Yellow, Blue and Red) with the cationic surfactant dodecyltrimethylammoniumbromide (DTAB) was studied to probe dye–DTAB binding stoichiometry and assembly morphology. For each dye, phase separation was observed above a given dye : DTAB ratio with the ratio depending on the dye. While Yellow and DTAB showed liquid/liquid phase separation above Yellow : DTAB = 1 : 1.67, crystalline dye–DTAB complexes were observed for Blue–DTAB and Red–DTAB above Blue : DTAB = 1 : 2.56 and Red : DTAB = 1 : 2.94 respecively. In homogeneous solution, UV/vis spectroscopic investigations suggest stochiometries of Yellow : DTAB = 1 : 2, Blue : DTAB = 1 : 3 and Red : DTAB = 1 : 4. It was concluded, that Yellow exhibits the highest dye : DTAB binding stoichiometry in both, dye–surfactant complexes in the 2-phase region and in solution, whereas the lowest dye : DTAB binding stoichiometry was observed for Red–DTAB in both cases. The observed stoichiometries are inversely correlated to the impact dye addition has on the morphology of DTAB micelles. Generally, addition of dye to DTAB micelles leads to a reduction in spontaneous curvature of these micelles and to the formation of triaxial ellipsoidal or cylindrical micelles from oblate ellipsoidal DTAB micelles. At a DTAB concentration of 30 mM and a dye concentration of 5 mM, this effect was most pronounced for Red and least pronounced for Yellow, whilst Blue showed an intermediate effect.
KW - Dye
KW - DTAB
KW - SAXS
KW - Small-angle X-ray scattering
KW - X-ray scattering
KW - Data analysis
KW - Micelle
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576978
DO - https://doi.org/10.1039/D3SM00501A
SN - 1744-683X
VL - 19
IS - 24
SP - 4588
EP - 4598
PB - Royal Society of Chemistry
AN - OPUS4-57697
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heyn, A.
A1 - Kotula, Stefan
A1 - Ebell, Gino
A1 - Babutzka, M.
T1 - Results of a Round Robin Test for the Determination of Polarization Resistances on Differently Weathered Zinc Samples Using Gel Electrolytes
N2 - This article presents the results of a round robin test throughout Germany with 19 participating institutions. Corrosion productlayer resistances (RL ) were determined on two differently weathered pure zinc samples and a sample activated with NaOH bymeans of electrochemical measurement of the linear polarization resistance (LPR) using agar‐based gel electrolytes. The roundrobin test was organized by the Bundesanstalt für Materialforschung und ‐prüfung (BAM) in Berlin. The measurements werecarried out by the participants in the period from May to July 2021. The results are summarized in this article comprising anassessment of the reproducibility and repeatability of the measurements. The methodology is suitable for distinguishing zincsurfaces after exposure to different atmospheres based on the corrosion product layer resistances (RL). In addition, possibleproblems in the application of the method were identified, and solutions for improving reproducibility and repeatability arediscussed. The results and knowledge from the round robin test are incorporated into a new test standard (DIN 50023:2024‐07)for this measurement method
KW - Corrosion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630546
DO - https://doi.org/10.1002/maco.202414696
SN - 1521-4176
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-63054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Delgado Arroyo, Diego
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Boerner, Andreas
A1 - Rhode, Michael
A1 - Lindner, T.
A1 - Preuß, B.
A1 - Lampke, T.
T1 - Influence of Milling Conditions on AlxCoCrFeNiMoy Multi-Principal-Element Alloys
N2 - Multi-Principal-Element or High-Entropy Alloys (MPEAs/HEAs) have gained increasing interest in the past two decades largely due to their outstanding properties such as superior mechanical strength and corrosion resistance. However, research studies on their processability are still scarce. This work assesses the effect of different machining conditions on the machinability of these novel alloys, with the objective of advancing the introduction of MPEA systems into industrial applications. The present study focuses on the experimental analysis of finish-milling conditions and their effects on the milling process and resulting surface finish of CoCrFeNi, Al0.3CoCrFeNi and Al0.3CoCrFeNiMo0.2 alloys fabricated via Spark Plasma Sintering. Ball-nose-end milling experiments have been carried out various milling parameters such as cutting speed, feed per cutting edge, and ultrasonic assistance. In situ measurements of cutting forces and temperature on the tool edge were performed during the experiments, and surface finish and tool wear were analyzed afterwards. The results exhibited decreasing cutting forces by means of low feed per cutting edge and reduced process temperatures at low cutting speed, with the use of ultrasonic-assisted milling. It was shown that the machinability of these modern alloys through conventional, as well as modern machining methods such as ultrasonic-assisted milling, is viable, and common theories in machining can be transferred to these novel MPEAs.
KW - Multi-principal element alloys
KW - Finish milling
KW - Spark plasma sintering
KW - Ultrasonic-assisted milling
KW - Microstructure characterization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572990
DO - https://doi.org/10.3390/coatings13030662
VL - 13
IS - 3
SP - 1
EP - 18
PB - MDPI (Multidisciplinary Digital Publishing Institute)
CY - Basel (CH)
AN - OPUS4-57299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buzolin, R.H.
A1 - Richter, Tim
A1 - Pixner, F.
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Enzinger, N.
T1 - Microstructure and texture characterisation of friction stir welded CoCrNi and CoCrFeMnNi multi-principle element alloys
N2 - This work investigates the microstructure formed in friction stir welds of FCC alloys, focused on two multiprincipal alloys: a CoCrFeMnNi high-entropy alloy (HEA) and a CoCrNi medium-entropy alloy (MEA). A commercial stainless steel AISI 304 is used for comparison. The largest nugget was formed in the MEA, while the smallest was formed in the HEA. Grain refinement occurs in the stirred zone in all welds. Discontinuous dynamic recrystallisation is the predominant restoration mechanism during friction stir welding of the three investigated alloys. A sharp decrement in the Σ3 boundary fraction occurs in the stirred zone of the AISI 304 and HEA welds, while comparable values with the base metal are found for the MEA weld. The peak in the maximum index of crystallographic texture is observed on the advancing side of the stirred zone of the AISI 304 weld. A strong <001> θ-fibre texture is formed in the advancing side of the nugget in the AISI 304 from a well-established {123} <634> S-type texture in the base metal. Multiple crystallographic texture components without specific fibres are identified in most regions of the welds, indicating the complex shear path history during friction stir welding.
KW - Microstructure
KW - Multiple principal element alloy
KW - Friction stir welding
KW - Electron backscattered diffraction
KW - Crystallographic texture
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572987
DO - https://doi.org/10.1016/j.mtcomm.2023.105870
VL - 35
SP - 1
EP - 14
PB - Elsevier Ltd.
CY - Amsterdam (NL)
AN - OPUS4-57298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ebell, Gino
A1 - Mayer, T. F.
A1 - Harnisch, J.
A1 - Dauberschmidt, Ch.
T1 - Corrosion monitoring of reinforced concrete structures:The DGZfP specification B12 Collaboration
N2 - Corrosion monitoring of reinforced or prestressed concrete structures has becomeincreasingly important in recent years. Areas of application include componentsthat are no longer accessible after completion or where potential fieldmeasurements cannot be carried out due to existing coatings. Corrosion monitoringcan also be used to monitor the progress of corrosion in corroding systems, e.g. to prove the success of repair measures according to repair principle 8 in accordancewith EN 1504‐9 or repair method 8.3 in accordance with the DIBt repair guideline.It also could be used to prove the functionality of cathodic corrosion protectionsystems in accordance with ISO 12696. Despite the increasing importance ofcorrosion monitoring, no guidelines orrecommendations existed until 2018. Thisgap was closed by the English version of specification B12,“Corrosion Monitoringof Reinforced and Prestressed Concrete Structures,”of the German Society for Non‐Destructive Testing, which was published in 2021. This article introducesspecification B12 by explaining the basicmeasurement principles and illustratingthe potential of corrosion monitoring in new and existing buildings.
KW - Corrosion
KW - Monitoring
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580982
DO - https://doi.org/10.1002/maco.202313934
SN - 0947-5117
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-58098
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Z.
A1 - Villa Santos, C.
A1 - Legrand, A.
A1 - Haase, F.
A1 - Hara, Y.
A1 - Kanamori, K.
A1 - Aoyama, T.
A1 - Urayama, K.
A1 - Doherty, C. M.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Colon, Y. J.
A1 - Furukawa, S.
T1 - Multiscale structural control of linked metal–organic polyhedra gel by aging-induced linkage-reorganization
N2 - Assembly of permanently porous metal–organic polyhedra/cages (MOPs) with bifunctional linkers leads to soft supramolecular networks featuring both porosity and processability. However, the amorphous nature of such soft materials complicates their characterization and thus limits rational structural control. Here we demonstrate that aging is an effective strategy to control the hierarchical network of supramolecular gels, which are assembled from organic ligands as linkers and MOPs as junctions. Normally, the initial gel formation by rapid gelation leads to a kinetically trapped structure with low controllability. Through a controlled post-synthetic aging process, we show that it is possible to tune the network of the linked MOP gel over multiple length scales. This process allows control on the molecular-scale rearrangement of interlinking MOPs, mesoscale fusion of colloidal particles and macroscale densification of the whole colloidal network. In this work we elucidate the relationships between the gel properties, such as porosity and rheology, and their hierarchical structures, which suggest that porosity measurement of the dried gels can be used as a powerful tool to characterize the microscale structural transition of their corresponding gels. This aging strategy can be applied in other supramolecular polymer systems particularly containing kinetically controlled structures and shows an opportunity to engineer the structure and the permanent porosity of amorphous materials for further applications.
KW - SAXS
KW - Metal-organic polyhedra
KW - Structural control
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532309
DO - https://doi.org/10.1039/d1sc02883a
SN - 1478-6524
SN - 1742-2183
VL - 12
IS - 38
SP - NIL_1
EP - NIL_9
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-53230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kool, L.
A1 - Dekker, F.
A1 - Bunschoten, A.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Velders, A. H.
A1 - Saggiomo, V.
T1 - Gold and silver dichroic nanocomposite in the quest for 3D printing the Lycurgus cup
N2 - The Lycurgus cup is an ancient glass artefact that shows dichroism as it looks green when a white light is reflected on it and a red colouring appears when a white light is transmitted through it. This peculiar dichroic effect is due to silver and gold nanoparticles present in the glass. In this research we show the synthesis of dichroic silver nanoparticles and their embedding in a 3D printable nanocomposite. The addition of gold nanoparticles to the silver nanoparticle composite, gave a 3D printable nanocomposite with the same dichroism effect of the Lycurgus cup.
KW - SAXS
KW - Au
KW - Ag
KW - Nanocomposite
KW - 3D printing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-501831
DO - https://doi.org/10.3762/bjnano.11.2
SP - 16
EP - 23
AN - OPUS4-50183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friberg, I.
A1 - Clark, A. H.
A1 - Ho, P.
A1 - Sadokhina, N.
A1 - Smales, Glen Jacob
A1 - Woo, J.
A1 - Auray, X.
A1 - Ferri, D.
A1 - Nachtegaal, M.
A1 - Krocher, O.
A1 - Olsson, L.
T1 - Structure and performance of zeolite supported Pd for complete methane oxidation
N2 - The influence of zeolite support materials and their impact on CH4 oxidation activity was studied utilizing Pd supported on H-beta and H-SSZ-13. A correlation between CH4 oxidation activity, Si/Al ratio (SAR), the type of zeolite framework, reduction-oxidation behaviour, and Pd species present was found by combining catalytic activity measurements with a variety of characterization methods (operando XAS, NH3-TPD, SAXS, STEM and NaCl titration). Operando XAS analysis indicated that catalysts with high CH4 oxidation activity experienced rapid transitions between metallic- and oxidized-Pd states when switching between rich and lean conditions. This behaviour was exhibited by catalysts with dispersed Pd particles. By contrast, the formation of ion-exchanged Pd2+ and large Pd particles appeared to have a detrimental effect on the oxidation-reduction behaviour and the conversion of CH4. The formation of ion-exchanged Pd2+ and large Pd particles was limited by using a highly siliceous beta zeolite support with a low capacity for cation exchange. The same effect was also found using a small-pore SSZ-13 zeolite due to the lower mobility of Pd species. It was found that the zeolite support material should be carefully selected so that the well-dispersed Pd particles remain, and the formation of ion-exchanged Pd2+ is minimized.
KW - SAXS
KW - Zeolites
KW - Methane Oxidation
KW - XAS
KW - Catalysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529606
DO - https://doi.org/10.1016/j.cattod.2020.11.026
VL - 382
SP - 3
EP - 12
PB - Elsevier B.V.
AN - OPUS4-52960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hunter, R. D.
A1 - Rowlandson, J. L.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Ting, V. P.
A1 - Kulak, A.
A1 - Schnepp, Z.
T1 - The effect of precursor structure on porous carbons produced by iron-catalyzed graphitization of biomass
N2 - This paper reports a systematic study into the effect of different biomass-derived precursors on the structure and porosity of carbons prepared via catalytic graphitization. Glucose, starch and cellulose are combined with iron nitrate and heated under a nitrogen atmosphere to produce Fe3C nanoparticles, which catalyze the conversion of amorphous carbon to graphitic nanostructures. The choice of organic precursor provides a means of controlling the catalyst particle size, which has a direct effect on the porosity of the material. Cellulose and glucose produce mesoporous carbons, while starch produces a mixture of micro- and mesopores under the same conditions and proceeds via a much slower graphitization step, generating a mixture of graphitic nanostructures and turbostratic carbon. Porous carbons are critical to energy applications such as batteries and electrocatalytic processes. For These applications, a simple and sustainable route to those carbons is essential. Therefore, the ability to control the precise structure of a biomass-derived carbon simply through the choice of precursor will enable the production of a new generation of energy materials.
KW - SAXS
KW - Porous carbons
KW - Graphitization
KW - Iron nanoparticles
KW - Catalysis
KW - Gas sorption
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515531
DO - https://doi.org/10.1039/d0ma00692k
VL - Royal Society of Chemistry
SP - 1
EP - 11
AN - OPUS4-51553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallau, Wilma
A1 - Recknagel, Christoph
A1 - Smales, Glen Jacob
T1 - Structural silicone sealants after exposure to laboratory test for durability assessment
N2 - During the service life of structural sealant glazing (SSG) facades, the loadbearing capacity of the silicone bonds needs to be guaranteed. Laboratory Tests can assess the durability of SSG-systems based on mechanical characteristics of the bond after simultaneous exposure to both climatic and mechanical loads.
This article studies how the material characteristics of two common structural sealants are affected by laboratory and field exposure. Dynamic mechanical Analysis (DMA) confirms a reduction in the dynamic modulus of exposed Silicone samples. Results from thermogravimetric analysis, Fourier-transform infrared spectroscopy, differential scanning calorimetry, and small-angle X-ray scattering/wide-angle X-ray scattering show differences between the two sealants and indicate no/minor changes in the composition and morphology of the laboratory and field exposed sealants. Mechanical characterization methods, such as DMA, and tensile and shear testing of the structural bond, are shown to be sensitive toward the combined climatic and mechanical loadings, and are hence suitable for studying degradation mechanisms of structural sealants.
KW - Aging
KW - Analytical methods
KW - Fatigue
KW - Silicone elastomer
KW - Structural sealant glazing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527217
DO - https://doi.org/10.1002/app.50881
VL - 138
IS - 35
SP - 50881
PB - Wiley
AN - OPUS4-52721
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
T1 - The MOUSE project - A meticulous approach for obtaining traceable, wide-range X-ray scattering information
N2 - Herein, we provide a "systems architecture"-like overview and detailed discussions of the methodological and instrumental components that, together, comprise the "MOUSE" project (Methodology Optimization for UltrafineStructure Exploration). The MOUSE project provides scattering information on a wide variety of samples, with traceable dimensions for both the scattering vector (q) and the absolute scattering cross-section (I). The measurable scattering vector-range of 0.012≤ q (nm-1) ≤ 92, allows information across a hierarchy of structures with dimensions ranging from ca. 0.1 to 400 nm. In addition to details that comprise the MOUSE project, such as the organisation and traceable aspects, several representative examples are provided to demonstrate its flexibility. These include measurements on alumina membranes, the tobacco mosaic virus, and dual-source information that overcomes fluorescence limitations on ZIF-8 and iron-oxide-containing carbon catalyst materials.
KW - X-ray scattering
KW - MOUSE
KW - Instrumentation
KW - SAXS
KW - Methodology
KW - Traceability
KW - Wide-range
KW - Data curation
KW - FAIR
KW - Uncertainties
KW - Nanomaterials
KW - Nanometrology
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528669
DO - https://doi.org/10.1088/1748-0221/16/06/P06034
VL - 16
IS - 6
SP - 1
EP - 50
PB - IOP
CY - Bristol, UK
AN - OPUS4-52866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bernardy, Christopher
A1 - Habib, Abdel Karim
A1 - Kluge, Martin
A1 - Schalau, Bernd
A1 - Schulze, Marcel
A1 - Kant, Hanjo
A1 - Orchini, Alessandro
ED - Di Benedetto, Almerinda
ED - Portarapillo, Maria
T1 - Investigation of the thermal radiation from hydrogen jet flames
N2 - For industrial applications dealing with hydrogen, the definition of safety distances and the assessment of possible hazards emanating from releases is mandatory. Since hydrogen is usually stored and transported under pressure, one scenario to be considered is the momentum driven release of hydrogen from a leakage with subsequent ignition. In this scenario, the emitted heat radiation from the resulting jet flame to the surroundings has to be determined to define adequate safety distances. For hydrocarbon flames, different jet flame models are available to assess the hazards resulting from an ignited jet release. Since hydrogen flames differ from hydrocarbon flames in their combustion behavior, it has to be checked if these models are also applicable for hydrogen. To evaluate the accuracy of these models for hydrogen jet flames, tests at real-scale are carried out at the BAM Test Site for Technical Safety (BAM-TTS). Herein, the flame geometry and the heat radiation at defined locations in the surroundings are recorded for varying release parameters such as leakage diameter (currently up to 30 mm), release pressure (currently up to max. 250 bar) and mass flow (up to max. 0.5 kg/s). The challenge here is the characterization of the flame geometry in an open environment and its impact on the thermal radiation. Existing heat radiation data from the literature are mostly based on unsteady outflow conditions. For a better comparability with the steady state jet flame models, the experiments presented here are focused on ensuring a constant mass flow over the release duration to obtain a (quasi) stationary jet flame. In addition, stationary outflow tests with hydrocarbons (methane) were also carried out, which are intended to serve as reference tests for checking flame models based on hydrocarbon data.
T2 - 15th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions (ISHPMIE)
CY - Neaples, Italy
DA - 10.06.2024
KW - Hydrogen
KW - Release
KW - Jet flame
KW - Thermal radiation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605107
DO - https://doi.org/10.5281/zenodo.12515710
VL - 2024
SP - 1322
EP - 1333
PB - Zenodo
CY - Geneva
AN - OPUS4-60510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stajanca, Pavol
A1 - Chruscicki, Sebastian
A1 - Homann, Tobias
A1 - Seifert, Stefan
A1 - Schmidt, Dirk
A1 - Habib, Abdel Karim
T1 - Detection of leak-induced pipeline vibrations using fiber-optic distributed acoustic sensing
N2 - In the presented work, the potential of fiber-optic distributed acoustic sensing (DAS) for detection of small gas pipeline leaks (<1%) is investigated. Helical wrapping of the sensing fiber directly around the pipeline is used to increase the system sensitivity for detection of weak leak-induced vibrations. DAS measurements are supplemented with reference accelerometer data to facilitate analysis and interpretation of recorded vibration signals. The results reveal that a DAS system using direct fiber application approach is capable of detecting pipeline natural vibrations excited by the broadband noise generated by the leaking medium. In the performed experiment, pipeline vibration modes with acceleration magnitudes down to single ug were detected. Simple leak detection approach based on spectral integration of time-averaged DAS signals in frequency domain was proposed. Potential benefits and limitations of the presented monitoring Approach were discussed with respect to its practical applicability. We demonstrated that the approached is potentially capable of detection and localization of gas pipeline leaks with leak rates down to 0.1% of the pipeline flow volume and might be of interest for monitoring of short- and medium-length gas pipelines.
KW - Distributed acoustic sensing
KW - DAS
KW - Distributed vibration sensing
KW - DVS
KW - Fiber-optic sensors
KW - Pipeline monitoring
KW - Leak detection
KW - Pipeline vibrations
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457953
UR - http://www.mdpi.com/1424-8220/18/9/2841
DO - https://doi.org/10.3390/s18092841
SN - 1424-8220
VL - 18
IS - 9
SP - 2841, 1
EP - 18
PB - MDPI
AN - OPUS4-45795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Qi, Naiyu
A1 - Somaskandan, Rachana
A1 - Graeber, Gustav
T1 - High-Precision Surface Tension Measurements of Sodium, Potassium, and Their Alloys via Du Noüy Ring Tensiometry
N2 - The development of post-lithium-ion batteries has sparked significant interest in alkali-metal anodes, particularly sodium (Na), potassium (K), and sodium−potassium (Na−K) alloys. Na−K alloys are promising for partially liquid anodes due to their unique low melting points. A critical factor influencing Na−K-based anode performance is wetting behavior, which governs electrical conductivity, mechanical contact, and long-term stability. At the heart of wetting lies surface tension, a fundamental property of solid−liquid− gas interactions. However, the surface tension of alkali metals and their alloys, particularly Na−K systems, remains poorly understood due to experimental and theoretical challenges. This study bridged these gaps by employing Du Noüy ring tensiometry for the first time in alkali-metal systems to measure the surface tension of Na, K, and Na−K alloys across temperatures from ambient to 180 °C. A key innovation in this work is the development of the push-in Du Noüy method, which provided significantly higher precision and reliability compared to the traditional pull-out technique, without requiring a correction factor. The measured surface tension decreased with increasing temperature for the studied Na−K alloys. For instance, for a eutectic Na−K mixture, the surface tension decreases from 121.7 mN m−1 to 112.2 mN m−1 when increasing the temperature from ambient to 180 °C. Additionally, this study presented the first use of Gibbs free energy minimization to model the surface tension of the Na−K system. The robust method significantly enhanced the predictive accuracy compared to the previous simplified model, reducing deviations from 25% to 2%. Our findings reveal that surface tension increases with sodium mole fraction in the bulk phase, yet the surface monolayer remains potassium-rich, indicating non-ideal surface behavior. This study deepens the understanding of alkali-metal wetting behavior, providing valuable insights for designing optimized interfaces in next-generation semi-solid alkali-metal batteries.
KW - Sodium−potassium alloy
KW - Liquid-metal anodes
KW - Alkali metal
KW - Batteries
KW - Surface tension
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630102
DO - https://doi.org/10.1021/acsami.5c02183
SN - 1944-8252
VL - 17
IS - 17
SP - 25985
EP - 25995
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-63010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Patrick
A1 - Schneider, Ronald
A1 - Baeßler, Matthias
A1 - Morgenthal, Guido
T1 - Parallelized adaptive Bayesian updating with structural reliability methods for inference of large engineering models
N2 - The reassessment of engineering structures, such as bridges, now increasingly involve the integration of models with realworld data. This integration aims to achieve accurate ‘as-is’ analysis within a digital twin framework. Bayesian model updating combines prior knowledge and data with models to enhance the modelling accuracy while consistently handling uncertainties. When updating large engineering models, numerical methods for Bayesian analysis present significant computational challenges due to the need for a substantial number of likelihood evaluations. The novelty of this contribution is to parallelize adaptive Bayesian Updating with Structural reliability methods combined with subset simulation (aBUS) to improve its computational efficiency. To demonstrate the efficiency and practical applicability of the proposed approach, we present a case study on the Maintalbrücke Gemünden, a large railway bridge. We leverage modal property data to update a linear-elastic dynamic structural model of the bridge. The parallelized aBUS approach significantly reduces computational time, making Bayesian updating of large engineering models feasible within reasonable timeframes. The improved efficiency allows for a wider implementation of Bayesian model updating in structural health monitoring and maintenance decision support systems.
KW - Bayesian model updating
KW - Bayesian updating with structural reliability methods
KW - Structural health monitoring
KW - Parallelization
KW - Modal analysis
KW - Railway bridge
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633686
DO - https://doi.org/10.1177/13694332251346848
SN - 1369-4332
SN - 2048-4011
SP - 1
EP - 26
PB - Sage
AN - OPUS4-63368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Benseghier, Z.
A1 - Cuéllar, Pablo
A1 - Luu, L.-H.
A1 - Bonelli, S.
A1 - Philippe, P.
T1 - A parallel GPU-based computational framework for the micromechanical analysis of geotechnical and erosion problems
N2 - This article deals with the relevance and practical feasibility of micromechanical simulations for their application to general geomechanical problems involving fluid-saturated granular assemblies, whether frictional or cohesive. A set of conceptual and numerical tools is here presented, advocating for a parallel computation using graphical processing units (GPUs) to treat large numbers of degrees of freedom with conventional Desktop computers. The fluid phase is here simulated with a particle-resolved approach in the frame of the Lattice Botzmann Method (LBM) while the granular solid phase is modelled as a collection of discrete particles from a Molecular Dynamics DEM perspective. The range of possible material behaviours for the solid granular phase is intended here to cover a broad spectrum from purely frictional to viscous cohesive materials with either brittle or transient debonding features. Specific details of the implementation and some validation cases are put forward.
Finally, some exemplary applications in the fields of soil erosion and geotechnical profile installation are provided along with a discussion on the parallel performance of the presented models. The results show that a micromechanical approach can be feasible and useful in practice, providing meaningful insights into complex engineering problems like the erosion kinetics of a soil under an impinging jet or the penetration resistance of a deep foundation in a layered soil profile.
KW - Offshore geomechanics
KW - Erosion
KW - Micromechanical modelling
KW - LBM-DEM
KW - GPU Parallel computing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502309
DO - https://doi.org/10.1016/j.compgeo.2019.103404
VL - 120
SP - Paper 103404, 1
PB - Elsevier Ltd.
AN - OPUS4-50230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - García-González, M.
A1 - Blasón Gonzalez, Sergio
A1 - García-García, I.
A1 - Lamela-Rey, M. J.
A1 - Fernández-Canteli, A.
A1 - Álvarez-Arenal, Á.
T1 - Optimized planning and evaluation of dental implant fatigue testing: A specific software application
N2 - Mechanical complications in implant-supported fixed dental prostheses are often related to implant and prosthetic design. Although the current ISO 14801 provides a framework for the evaluation of dental implant mechanical reliability, strict adherence to it may be difficult to achieve due to the large number of test specimens which it requires as well as the fact that it does not offer any probabilistic reference for determining the endurance limit. In order to address these issues, a new software program called ProFatigue is presented as a potentially powerful tool to optimize fatigue testing of implant-supported prostheses. The present work provides a brief description of some concepts such as load, fatigue and stress-number of cycles to failure curves (S-N curves), before subsequently describing the current regulatory situation. After analyzing the two most recent versions of the ISO recommendation (from 2008 and 2016), some limitations inherent to the experimental methods which they propose are highlighted. Finally, the main advantages and instructions for the correct implementation of the ProFatigue free software are given. This software will contribute to improving the performance of fatigue testing in a more accurate and optimized way, helping researchers to gain a better understanding of the behavior of dental implants in this type of mechanical test.
KW - Dental materials
KW - Prostheses
KW - Implants
KW - Reference standards
KW - Software
KW - Cyclic loading
KW - Fatigue
KW - Lifetime
KW - S-N curve
KW - Staircase method
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516268
DO - https://doi.org/10.3390/biology9110372
SN - 2079-7737
VL - 9
IS - 11
SP - 372-1
EP - 372-12
PB - MDPI
CY - Basel
AN - OPUS4-51626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monavari, M.
A1 - Medhekar, R.
A1 - Nawaz, Q.
A1 - Monavari, Mehran
A1 - Fuentes‐Chandía, M.
A1 - Homaeigohar, S.
A1 - Boccaccini, A. R.
T1 - A 3D printed bone tissue engineering scaffold composed of alginate dialdehyde-gelatine reinforced by lysozyme loaded cerium doped mesoporous silica-calcia nanoparticles
N2 - A novel biomaterial comprising alginate dialdehyde-gelatine (ADA-GEL) hydrogel augmented by lysozyme loaded mesoporous cerium doped silica-calcia nanoparticles (Lys-Ce-MSNs) is 3D printed to create bioactive scaffolds. Lys-Ce-MSNs raise the mechanical stiffness of the hydrogel composite scaffold and induce surface apatite mineralization, when the scaffold is immersed in simulated body fluid (SBF). Moreover, the scaffolds can co-deliver bone healing (Ca and Si) and antioxidant ions (Ce), and Lys to achieve antibacterial (and potentially anticancer) properties. The nanocomposite hydrogel scaffolds can hold and deliver Lys steadily. Based on the in vitro results, the hydrogel nanocomposite containing Lys assured improved pre-osteoblast cell (MC3T3-E1) proliferation, adhesion, and differentiation, thanks to the biocompatibility of ADA-GEL, bioactivity of Ce-MSNs, and the stabilizing effect of Lys on the scaffold structure. On the other hand, the proliferation level of MG63 osteosarcoma cells decreased, likely due to the effect of Lys. Last but not least, cooperatively, alongside gentamicin (GEN), Lys brought about a proper antibacterial efficiency to the hydrogel nanocomposite scaffold against gram-positive and gram-negative bacteria. Taken together, ADA-GEL/Lys-Ce-MSN nanocomposite holds great promise for 3D printing of multifunctional hydrogel bone tissue engineering (BTE) scaffolds, able to induce bone regeneration, address infection, and potentially inhibit tumor formation and growth.
KW - Materials chemistry
KW - Polymers and plastics
KW - Biomaterials
KW - Bioengineering
KW - Biotechnology
KW - 3D printing
KW - Bone tissue engineering
KW - Drug delivery
KW - Lysozyme
KW - Mesoporous SiO2-CaO nanoparticles
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581238
DO - https://doi.org/10.1002/mabi.202200113
SN - 1616-5195
VL - 22
IS - 9
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-58123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernádez-Canteli, A.
A1 - Castillo, E.
A1 - Blasón Gonzalez, Sergio
T1 - A methodology for phenomenological analysis of cumulative damage processes. Application to fatigue and fracture phenomena
N2 - Sample functions, i.e., stochastic process realizations, are used to define cumulative damage phenomena which end into an observable terminal state or failure. The complexity inherent to such phenomena justifies the use of phenomenological models associated with the evolution of a physical magnitude feasible to be monitored during the test. Sample functions representing the damage evolution may be identified, once normalized to the interval [0,1], with cumulative distribution functions (cdfs), generally, of the generalized extreme value (GEV) family. Though usually only a fraction of the whole damage evolution, according to the specific problem handled, is available from the test record, the phenomenological models proposed allow the whole damage process to be recovered. In this way, down- and upwards extrapolations of the whole damage process beyond the scope of the experimental program are provided as a fundamental tool for failure prediction in the practical design. The proposed methodology is detailed and its utility and generality confirmed by its successive application to representative well-known problems in fatigue and fracture characterization. The excellent fittings, the physical interpretation of the model parameters and the good expectations to achieve a complete probabilistic analysis of these phenomena justify the interest of the proposed phenomenological approach with possible applications to other cumulative damage processes.
KW - Bayesian technique
KW - Sample random results
KW - Stochastic sample functions
KW - Probabilistic assessment
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552371
DO - https://doi.org/10.1016/j.ijfatigue.2021.106311
SN - 0142-1123
VL - 150
SP - 106311
PB - Elsevier Ltd.
AN - OPUS4-55237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nourinejhad Zarghani, Shaheen
A1 - Ehlers, Jens
A1 - Monavari, Mehran
A1 - von Bargen, Susanne
A1 - Hamacher, Joachim
A1 - Büttner, Carmen
A1 - Bandte, Martina
T1 - Applicability of Different Methods for Quantifying Virucidal Efficacy Using MENNO Florades and Tomato Brown Rugose Fruit Virus as an Example
N2 - After entry of a quarantine/regulated pathogen, infected plants shall be destroyed, and the cultivated area (e.g., greenhouse) shall be disinfected. Therefore, the selection of an effective disinfectant plays an important role. With the availability of different methods for virus quantification, we investigated the application of quantitative ELISA (qELISA), RT-qPCR (reverse transcription-quantitative polymerase chain reaction), and bioassays for the quantification of disinfectant efficacy. Therefore, we estimated the titer reduction in tomato brown rugose fruit virus (ToBRFV), a regulated pathogen, in plant sap and on germ carriers after treatment with MENNO Florades 4% for 16 h. The virus load before and after the treatment was measured with the mentioned methods. The RT-qPCR and qELISA methods showed very low efficacy in the presence of the disinfectant. Although bioassays are time-consuming, need purified particles for establishing the quantification models, and are less sensitive than RT-qPCR, they were able to quantify the differences in virus titer in the presence/absence of disinfectant. Interestingly, the bioassays reached at least the lower limit sensitivity of a qELISA. By being less sensitive to the presence of the disinfectant, bioassays proved to be the only technique for the determination of the disinfectant efficacy against ToBRFV on different germ carriers as well as on virus-infected plant sap.
KW - Plant Science
KW - Ecology
KW - Evolution
KW - Behavior and Systematics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585497
DO - https://doi.org/10.3390/plants12040894
VL - 12
IS - 4
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-58549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nourinejhad Zarghani, Shaheen
A1 - Monavari, Mehran
A1 - Ehlers, Jens
A1 - Hamacher, Joachim
A1 - Büttner, Carmen
A1 - Bandte, Martina
T1 - Comparison of Models for Quantification of Tomato Brown Rugose Fruit Virus Based on a Bioassay Using a Local Lesion Host
N2 - Considering the availability of serological and molecular biological methods, the bioassay has been paled into insignificance, although it is the only experimental method that can be used to demonstrate the infectivity of a virus. We compared goodness-of-fit and predictability power of five models for the quantification of tomato brown rugose fruit virus (ToBRFV) based on local lesion assays: the Kleczkowski model, Furumoto and Mickey models I and II, the Gokhale and Bald model (growth curve model), and the modified Poisson model. For this purpose, mechanical inoculations onto Nicotiana tabacum L. cv. Xanthi nc and N. glutionosa L. with defined virus concentrations were first performed with half-leaf randomization in a Latin square design. Subsequently, models were implemented using Python software and fitted to the number of local lesions. All models could fit to the data for quantifying ToBRFV based on local lesions, among which the modified Poisson model had the best prediction of virus concentration in spike samples based on local lesions, although data of individual indicator plants showed variations. More accurate modeling was obtained from the test plant N. glutinosa than from N. tabacum cv. Xanthi nc. The position of the half-leaves on the test plants had no significant effect on the number of local lesions.
KW - Plant Science
KW - Ecology
KW - Evolution
KW - Behavior and Systematics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585506
DO - https://doi.org/10.3390/plants11243443
VL - 11
IS - 24
SP - 1
EP - 16
PB - MDPI
AN - OPUS4-58550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Balscheit, Hagen
A1 - Geißler, Peter
A1 - Cuéllar, Pablo
A1 - Basedau, Frank
A1 - Baeßler, Matthias
T1 - Large-scale field tests on plastic pile tip failure upon monopile installation
N2 - Large-diameter monopiles are the most common foundation structures for offshore wind turbines. One relevant failure mode during installation is plastic failure of the pile tip which may increase progressively during further driving (pile tip buckling; extrusion buckling). This paper presents the details and results of a large-scale field-test campaign with dynamic pile installation for the validation and calibration of different numerical approaches concerning pile-tip buckling phenomena. The phenomenology of observed pile-tip failures is here described in detail and a first quantitative approach is evaluated based on the field-test data. As the number of new projects continues to grow and the necessity to construct wind farms in challenging terrain increases, such field data-sets will become increasingly relevant.
KW - Monopile
KW - Offshore Windenergy
KW - Pfahlfußbeulen
KW - Pile Tip Buckling
KW - Reference Tests
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611651
DO - https://doi.org/10.1016/j.oceaneng.2024.119322
VL - 313
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-61165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Balscheit, Hagen
A1 - Victor, A.
A1 - Thiele, Marc
A1 - Cuéllar, Pablo
A1 - Baeßler, Matthias
A1 - Lüddecke, F.
T1 - Experimental Investigation on Buckling Behavior of soil-embedded Piles
N2 - Monopiles are currently the predominant foundation type for offshore wind turbines in Europe. Due to the increasing dimensions of the turbines, pile diameters beyond 10m become necessary. A design-relevant failure mode of monopiles is the local buckling of the pile wall in the embedded sections. Relevant buckling guidelines do not consider the soil-structure interaction specifically, although the embedment may allow for a reduction of wall thickness. However, Eurocode-based design concepts require a validation with comparative buckling cases for validation, either in terms of buckling curve parameters for both the algebraic stress-based and semi-numerical LBA/MNA design concept or as a calibration factor kGMNIA for fully numerical GMNIA calculations. These parameters are not yet available for embedded shells. To close this gap, we have conducted experiments on piles embedded in sand to investigate local buckling under soil-structure-interaction. The results will be used to calibrate numerical models. This research was carried out as part of the VERBATIM research project, funded by PTJ/BMWK and supported by the Carbon Trust's Offshore Wind Accelerator consortium.
T2 - EUROSTEEL 2023
CY - Amsterdam, The Netherlands
DA - 11.09.2023
KW - Wind
KW - Wind Energy
KW - Shell Buckling
KW - Offshore
KW - Soil-Structure-Interaction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583641
DO - https://doi.org/10.1002/cepa.2313
SN - 2509-7075
VL - 6
IS - 3-4
SP - 1729
EP - 1734
PB - Ernst & Sohn Gmb
AN - OPUS4-58364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zinas, Orestis
A1 - Papaioannou, Iason
A1 - Schneider, Ronald
A1 - Cuéllar, Pablo
A1 - Baeßler, Matthias
T1 - 3D spatial modelling of CPT data for probabilistic preliminary assessment of potential pile tip damage upon collision with boulders
N2 - Tip damage of monopiles from boulder collisions during installation has emerged as a critical design issue, primarily due to the combination of the widespread use of large-diameter piles and the complexity of the ground conditions at the available sites. Recently, a framework relating potential pile tip damage to cone tip resistance from Cone Penetration Tests (CPTs) has been proposed in the literature. Gaussian processes are powerful stochastic models that enable probabilistic spatial interpolation of soil data at any location within a site. On this basis, this study utilizes sparse CPT data from a site in the North Sea, to first develop an efficient Gaussian process regression model, which is used to derive a three-dimensional (3D) probabilistic predictive map of the cone tip resistance. Assuming deterministic loading conditions and a factual collision with a boulder of pre-defined properties, the cone tip resistance predictive model is subsequently used for a probabilistic preliminary assessment of potential pile tip damage. Results of the analysis are realistic 3D probability maps of potential damage that aim to support engineering judgment and contribute towards cost-effective site investigation planning and offshore wind farm design.
T2 - 5th International Symposium on Frontiers in Offshore Geotechnics (ISFOG 2025)
CY - Nantes, France
DA - 09.06.2025
KW - CPT data
KW - Gaussian process regression
KW - Boulder impact
KW - Preliminary pile tip damage assessment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634417
SN - 978-2-85782-758-0
DO - https://doi.org/10.53243/ISFOG2025-323
SP - 505
EP - 510
PB - International Society for Soil Mechanics and Geotechnical Engineering
CY - London
AN - OPUS4-63441
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nourinejhad Zarghani, S.
A1 - Monavari, Mehran
A1 - Nourinejhad Zarghani, A.
A1 - Nouri, S.
A1 - Ehlers, J.
A1 - Hamacher, J.
A1 - Bandte, M.
A1 - Büttner, C.
T1 - Quantifying plant viruses: Evolution from bioassay to infectivity dilution curves along the model of tobamoviruses
N2 - This review describes the development of the bioassay as a means of quantifying plant viruses, with particular attention to tobamovirus. It delves into various models used to establish a correlation between virus particle concentration and the number of induced local lesions (the infectivity dilution curve), including the Poisson, Furumoto and Mickey, Kleczkowski, Growth curve, and modified Poisson models. The parameters of each model are described, and their application or performance in the context of the tobacco mosaic virus is explored. This overview highlights the enduring value of the infectivity dilution curve in tobamovirus quantification, providing valuable insights for researchers or practitioners of bioassays and theoreticians of modeling.
KW - Local lesion
KW - qRT-PCR
KW - Nicotiana
KW - ToBRFV
KW - TMV
KW - CGMMV
KW - Disinfection
KW - Modeling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630142
DO - https://doi.org/10.3390/v16030440
SN - 1999-4915
VL - 16
IS - 3
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-63014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krösche, C.
A1 - Malow, Marcus
A1 - Budde, K.
T1 - False-Positive Results of UN Test O.2 Liquid Oxidizer Test of Polychlorosilanes
N2 - According to UN Test O.2, surprisingly, the polychlorosilanes hexachlorodisilane (HCDS), octachlorotrisilane (OCTS) and decachlorotetrasilane (DCTS) formally fulfill the criteria of the “test for oxidizing liquids”. This result is in contrast to the properties of polychlorosilanes that are described in the literature and those we have experienced in our own production.
By investigating the reaction products from the UN O.2 test reactor, using IR, Raman and XPS spectroscopy, it was shown that the results are not due to oxidizing properties of HCDS, OCTS or DCTS, but are caused by the specified test substance cellulose. To our knowledge, this is the very first substance class in which the reference substance oxidizes the test sample, instead of vice versa. This represents an important limitation of the internationally used UN Test O.2 for this substance class. The cause for this false-positive result is the known high degree of affinity of oxygen to silicon.
It is shown that the correctly executed UN Test O.2 produces false-positive results and that the polychlorosilanes do not have an oxidizing effect and, therefore, do not have to be classified as “oxidizing substances”.
KW - Polychlorosilanes
KW - UN Test O.2
KW - Hexachlorodisilane
KW - Octachlortrisilane
KW - Decachlorotetrasilane
KW - False-positive results
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523989
DO - https://doi.org/10.1016/j.jlp.2021.104434
VL - 70
SP - 104434
PB - Elsevier Ltd.
AN - OPUS4-52398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Scheuschner, Nils
A1 - Chand, Keerthana
A1 - Altenburg, Simon
T1 - Local porosity prediction in metal powder bed fusion using in-situ thermography: A comparative study of machine learning techniques
N2 - The formation of flaws such as internal porosity in parts produced by Metal-based Powder Bed Fusion with Laser Beam (PBF-LB/M) significantly hinders its broader industrial application, as porosity can potentially lead to part failure. Addressing this issue, this study explores the efficacy of in-situ thermography, particularly short-wave infrared thermography, for detecting and predicting porosity during manufacturing. This technique is capable of monitoring the part’s thermal history which is closely connected to the flaw formation process. Recent advancements in Machine Learning (ML) have been increasingly leveraged for porosity prediction in PBF-LB/M. However, previous research primarily focused on global rather than localized porosity prediction which simplified the complex prediction task. Thereby, the opportunity to correlate the predicted flaw position with expected part strain to judge the severity of the flaw for part performance is neglected. This study aims to bridge this gap by studying the potential of SWIR thermography for predicting local porosity levels using regression models. The models are trained on data from two identical HAYNES®282® specimens. We compare the effectiveness of feature-based and raw data-based models in predicting different porosity types and examine the importance of input data in porosity prediction. We show that models trained on SWIR thermogram data can identify systematic trends in local flaw formation. This is demonstrated for forced flaw formation using process parameter shifts and, moreover, for randomly formed flaws in the specimen bulk. Furthermore, we identify features of high importance for the prediction of lack-of-fusion and keyhole porosity from SWIR monitoring data.
KW - PBF-LB/M
KW - In situ monitoring
KW - Thermography
KW - Additive Manufacturing
KW - Process monitoring
KW - Porosity prediction
KW - Machine Learning
KW - Feature extraction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621798
DO - https://doi.org/10.1016/j.addma.2024.104502
SN - 2214-7810
VL - 95
SP - 1
EP - 17
PB - Elsevier B.V.
AN - OPUS4-62179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Heat control and design‑related effects on the properties and welding stresses in WAAM components of high‑strength structural steels
N2 - Commercial high-strength fller metals for wire arc additive manufacturing (WAAM) are already available. However, widespread industrial use is currently limited due to a lack of quantitative knowledge and guidelines regarding welding stresses and component safety during manufacture and operation for WAAM structures. In a joint research project, the process- and material-related as well as design infuences associated with residual stress formation and the risk of cold cracking are being investigated. For this purpose, reference specimens are welded fully automated with defned dimensions and systematic variation of heat control using a special, high-strength WAAM fller metal (yield strength>790 MPa). Heat control is varied by means of heat input (200–650 kJ/m) and interlayer temperature (100–300 °C). The ∆t8/5 cooling times correspond with the recommendations of fller metal producers (approx. 5–20 s). For this purpose, additional thermo-physical forming simulations using a dilatometer allowed the complex heat cycles to be reproduced and the resulting ultimate tensile strength of the weld metal to be determined. Welding parameters and AM geometry are correlated with the resulting microstructure, hardness, and residual stress state. High heat input leads to a lower tensile stress in the component and may cause unfavorable microstructure and mechanical properties. However, a sufciently low interlayer temperature is likely to be suitable for obtaining adequate properties at a reduced tensile stress level when welding with high heat input. The component design afects heat dissipation conditions and the intensity of restraint during welding and has a signifcant infuence on the residual stress. These complex interactions are analyzed within this investigation. The aim is to provide easily applicable processing recommendations and standard specifcations for an economical, appropriate, and crack-safe WAAM of high-strength steels.
KW - GMA welding
KW - Additive manufacturing
KW - Residual stresses
KW - High-strength steel
KW - Cold cracking safety
KW - Heat control
KW - Wind energy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567397
DO - https://doi.org/10.1007/s40194-022-01450-x
SN - 1878-6669
VL - 2022
SP - 1
EP - 11
PB - Springer
CY - Berlin
AN - OPUS4-56739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czeskleba, Denis
A1 - Nietzke, Jonathan
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Investigation of stress relief crack susceptibility of CrMoV steels coarse grain HAZ via simulation of uniaxial stress conditions during PWHT
N2 - Creep-resistant steels such as the 13CrMoV9-10, used in the construction of thick-walled pressure vessels, are most commonly submerged arc welded (SAW). These steels can develop stress relief cracks (SRC) if the mandatory post weld heat treatment (PWHT) is performed improperly. Current PWHT parameters, such as heating rate and holding time at a specific holding temperature, are based on both empirical experience and conventional free shrinking welding experiments to characterize the SRC-susceptibility of the weld. These cannot adequately depict the higher residual stresses caused by the structurally induced stiffness of the surrounding construction. This study discusses the development of a repeatable, precise, and time-efficient methodology to study the effects of different stress levels and heating rates on the SRC susceptibility of the coarse grain heat-affected zone (CGHAZ). For that purpose, samples were thermically treated to simulate a coarse grain heat-affected zone (CGHAZ) and subsequently exposed to representative levels of stress during the heating phase of a PWHT. The recorded stress and heating rate–dependent strains were mathematically analyzed via curve tracing/calculus to identify interdependent effects. This procedure facilitates the measurement of material characteristics such as carbide growth on grain boundaries at the µm-scale via an integrated value over the entire sample volume. The first and second derivatives show a slight, precipitate-dependent, increase in hardness of the sample, depending on the heating rate and applied stress. This new methodology generates an improved assessment of the SRC susceptibility of SAW microstructures of creep-resistant CrMoV steels.
KW - Submerged arc welding
KW - Creep-resistant steel
KW - Stress relief cracking
KW - Component-like test
KW - Post weld heat treatment
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576007
DO - https://doi.org/10.1007/s40194-023-01539-x
SN - 0043-2288
SP - 1
EP - 9
PB - Springer Nature
CY - Basel (CH)
AN - OPUS4-57600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Gustus, R.
A1 - Treutler, K.
A1 - Wesling, V.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Alloy modification for additive manufactured Ni alloy components—part I: effect on microstructure and hardness of Invar alloy
N2 - Alloy 36 (1.3912), also known as “Invar,” is an alloy with 36% nickel. The alloy has a remarkably low thermal expansion coefficient in certain temperature ranges. This peculiarity is called the invar effect, which was discovered in 1896 by the Swiss physicist Charles Édouard Guillaume. Therefore, it is used in applications in which dimensional stability is critical, such as molding tools for composite materials in aerospace, automotive applications, or liquified natural gas (LNG) cargo tanks. Moreover, increasingly complex structures and the optimization of resource efficiency also require additive manufacturing steps for the production or repair of components. Additively manufactured components have a heterogeneous microstructure and anisotropic mechanical properties. In addition, the manufactured components require subsequent machining surface finishing, like finish milling, to achieve their final contour. Nickel iron alloys are difficult to machine. Additionally, inhomogeneous microstructure may lead to unstable cutting forces and conditions. In part I of this investigation, the initial alloy 36 is modified with the elements Ti, Zr, and Hf up to a maximum of 0.33 wt.-%. The influence of the modification elements on the microstructure as well as on the hardness of the AM components is examined. Furthermore, one modification is applied to metal arc welding process and investigated. Part II focuses on the effect of the alloy modifications on machinability as well as on the surface integrity of plasma-transferred-arc-welded (PTA) and finish milled invar components.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - Alloy modification
KW - Alloy 36
KW - Plasma-transferred arc welding
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571777
DO - https://doi.org/10.1007/s40194-023-01510-w
SN - 0043-2288
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-57177
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Eissel, A.
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
T1 - Optimisation of surface residual stresses using ultrasonic‑assisted milling for wire‑arc additive manufactured Ni alloy components
N2 - Nickel alloys are cost intensive materials and generally classified as difficult-to-cut material. However, machining of these materials is needed especially in case of alloy 36 (1.3912), which is commonly used in mould construction for the production of fibre-reinforced composites. With regard to repair, modification and manufacturing of such components, additive manufacturing offers significant economic advantages. Nevertheless, subsequent machining steps are needed to achieve the final component contour and defined surface conditions. Dependent on the material and machining process conditions, detrimental tensile residual stresses may be the result on the machined surface, having negative impact on the component performance and safety. In this investigation, machining experiments were carried out on wire arc additive manufactured components made of alloy 36, varying the cutting speed and the feed rate. In addition, the conventional milling process (CM) was compared with a modern, hybrid machining process, the ultrasonic-assisted milling (US). The cutting forces and the surface-near residual stresses were analysed using X-ray diffraction. A significant improvement of the machinability as well as the surface integrity by using the ultrasonic assistance was observed, especially at low cutting speeds. The CM induced mainly tensile residual stresses, the US mainly compressive residual stresses.
KW - Surface integrity
KW - Ultrasonic-assisted milling
KW - Additive manufacturing
KW - Ni alloy
KW - Alloy 36
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575246
DO - https://doi.org/10.1007/s00170-023-11326-z
SN - 1433-3015
VL - 126
IS - 9
SP - 4191
EP - 4198
PB - Springer Nature
AN - OPUS4-57524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, Julien
A1 - Schröpfer, Dirk
A1 - Hamacher, M.
A1 - Michels, H.
A1 - Hamm, C.
A1 - Appelt, M.
A1 - Börner, Andreas
A1 - Kannengießer, Thomas
T1 - Tool development for hybrid finishing milling of iron aluminides
N2 - The importance of high-temperature materials made of iron aluminides (FeAl) has been increasing in light weight applications, e.g., airplane turbines, due to the high material’s specific strength. However, the highly economic production by means of permanent mold casting involves special microstructures for Fe26Al4Mo0.5Ti1B alloy components leading to difficult machinability for subsequent finishing milling and low surface qualities. Major effects of tool and machining parameter variation incorporating ultrasonic assistance on the milling process and surface integrity are shown. Loads for tool and component surface are significantly adjustable to enable an economic process chain regarding the surface integrity of safety-relevant components.
KW - Ultrasonic-assisted milling
KW - Iron aluminide
KW - Surface integrity
KW - Tool wear
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566294
DO - https://doi.org/10.1016/j.procir.2022.03.123
SN - 2212-8271
VL - 108
SP - 793
EP - 798
PB - Elsevier B.V.
AN - OPUS4-56629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Kromm, Arne
A1 - Mente, Tobias
A1 - Brackrock, Daniel
A1 - Czeskleba, Denis
A1 - Kannengießer, Thomas
T1 - Component test for the assessment of delayed hydrogen-assisted cracking in thick-walled SAW joints for offshore applications
N2 - Offshore wind turbines continuously increase in size and weight and demand adequate offshore foundations concepts like monopiles, tripods, or jackets. These components are typically constructed using submerged arc welding (SAW) with high-strength thick steel plates like the S420ML. During welding, the occurrence of delayed hydrogen-assisted cracking (HAC) must be anticipated. HAC is a critical combination of the local hydrogen concentration within a susceptible microstructure under certain mechanical load, i.e., the occurring (welding) residual stresses. The welding sequence of the thick-walled plates complicates the residual stress distribution due to the necessary repeated thermal cycling, i.e., welding seam/layer deposition to fill the joint. For that purpose, SAW with two-wire-technique was used to weld a specially designed and prototype-like mock-up of a real component with a thickness of 50 mm, filled with over 20 passes and a seam length of 1000 mm. Additional welded stiffeners simulated the effect of a high restraint, to achieve critical HAC conditions. The necessity of a minimum waiting time (MWT) before the NDT can be conducted (to exclude HAC) was critically verified by the application of ultrasonic testing of the welded joint at different time-steps of the NDT of up to 48 h after the completion welding. The residual stresses were determined by a robot XRD goniometer. Tensile residual stresses up to the yield limit are found both in the weld metal and in the heat-affected zone. Numerical modeling allowed the qualitative estimation of the hydrogen diffusion in the weld. No noticeable HAC occurrence was identified and confirms the high cracking resistance of the investigated material. Finally, the applicability of the MWT concept should be critically discussed.
KW - Hydrogen
KW - Cold cracking
KW - Minimum Waiting Time
KW - Offshore steel grade
KW - Component test
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591981
DO - https://doi.org/10.1007/s40194-023-01658-5
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-59198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Thomas, Maximilian
A1 - Kannengießer, Thomas
A1 - Gibmeier, Jens
T1 - On the interpretation of Varestraint and Transvarestraint hot cracking test results
N2 - The Varestraint test and its variant Transvarestraint are one of the most widely used techniques for evaluating a material solidification cracking sensitivity during welding. The result of such tests is a crack length which is proportional to the material’s cracking susceptibility. Nevertheless, the welding and load parameters can unintentionally influence the crack length, which in some cases can distort the material evaluation. An approach is described as to how these effects can be assessed with the aid of a digital crack analysis. The crack lengths are compared position-dependently with their possible propagation due to the weld pool movement during continuous loading. The index derived from this can be used by the operator to evaluate his test parameters. In addition, a comparison of the results of different Varestraint setups is made possible. Alongside experimental results, a numerical sensitivity analysis is presented on how individual welding and loading parameters can affect the crack lengths.
KW - Varestraint test
KW - Solidification cracking
KW - Weldability
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595089
DO - https://doi.org/10.1007/s40194-024-01706-8
SN - 0043-2288
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-59508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Nietzke, Jonathan
A1 - Kannengießer, Thomas
T1 - In situ measurement of hydrogen concentration in steel using laser‑induced breakdown spectroscopy (LIBS)
N2 - The ISO 3690 standard “Determination of hydrogen content in arc weld metal” requires a thermal activation of the diffusible hydrogen in a piece of weld metal for the subsequent ex situ concentration measurement by carrier gas hot extraction CGHE or thermal desorption spectroscopy (TCD). Laser-induced breakdown spectroscopy (LIBS) offers a time and spatially resolved, almost non-destructive, in situ measurement of hydrogen at surfaces without sample preparation. We measured hydrogen in steels, which were charged either electrochemically or by high-pressure hydrogen gas, and compared the results. Further, the feasibility of quantitative hydrogen line scan measurements with LIBS was demonstrated by measuring hydrogen at water jet cut surfaces. The hydrogen concentrations measured with the help of LIBS were compared with CGHE measurements. It was observed that hydrogen can be reliably measured with LIBS for concentrations larger than 2 wt.-ppm. The maximum hydrogen concentration achieved using electrochemical charging was 85.1 ppm. The results show that LIBS is a promising technique for time- and spatially resolved measurements of hydrogen in steels.
T2 - IIW Annual Assembly 2023
CY - Singapore
KW - LIBS
KW - Hydrogen measurement
KW - Welding
KW - Stainless steel
KW - Diffusible hydrogen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593664
DO - https://doi.org/10.1007/s40194-023-01677-2
SP - 1
EP - 9
PB - Springer
AN - OPUS4-59366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wandtke, Karsten
ED - Becker, Amadeus
ED - Schröpfer, Dirk
ED - Kromm, Arne
ED - Kannengießer, Thomas
ED - Scharf-Wildenhain, R.
ED - Hälsig, A.
ED - Hensel, J.
T1 - Residual Stress Evolution during Slot Milling for Repair Welding and Wire Arc Additive Manufacturing of High-Strength Steel Components
N2 - High-strength steels offer potential for weight optimization due to reduced wall thicknesses in modern constructions. Additive manufacturing processes such as Wire Arc Additive Manufacturing (WAAM) enable the resource-efficient production of structures. In the case of defects occurring in weld seams orWAAM components due to unstable process conditions, the economical solution is local gouging or machining and repair welding. It is important to understand the effects of machining steps on the multiaxial stress state in conjunction with the design-related shrinkage restraints. Research into how welding and slot milling of welds andWAAM structures affects residual stresses is still lacking. For this reason, component-related investigations with high-strength steels with yield strengths ≥790 MPa are carried out in our research. In-situ digital image correlation (DIC) and ex-situ X-ray diffraction (XRD) were used to analyze the stresses and strains induced on specimens during and after milling. The systematic analyses revealed a significant interaction of the stiffness and microstructure of the specimens with the initial residual stresses induced by welding. Subsequent repair welds can result in significantly higher residual stresses.
KW - High strength steels
KW - Additive manufacturing
KW - Residual stress
KW - Repair welding
KW - Ditigtal image correlation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593515
DO - https://doi.org/10.3390/met14010082
VL - 14
IS - 1
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-59351
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Nina
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Thermodynamic prediction of precipitations behaviour in HAZ of a gas metal arc welded S690QL with varying Ti and Nb content
N2 - For a significant increase in the strength of high-strength fine-grained structural steels with a nominal yield strength ≥690 MPa, the addition of microalloying elements such as Nb and Ti is required. The standard specifications for the chemical composition of these steels (e.g., in EN 10025-6) often only give the manufacturer limit contents to achieve the defined properties. The effect of the alloying elements in the heat affected zone (HAZ) is sometimes completely contrary.
This makes it difficult to adequately predict the batch dependency regarding weldability and the load-bearing behaviour of the welded joint. Three different micro-alloyed steels of the grade S690QL were produced on a laboratory scale, focusing on different Nb and Ti contents. To investigate the tempering effect, these were gas metal arc welded in three layers. In addition to metallographic investigations of individual HAZ areas, thermodynamic phase calculations were carried out using Thermo-Calc, following variations in the chemical composition. This provides an understanding of phase transformation, precipitation growth, and dissolution during welding as a function of temperature and cooling conditions. The results show
a divergent metallurgical behaviour in the HAZ of the three different micro-alloyed steels. Thereby, the Ti micro-alloyed grade showed a strong softening of the HAZ in contrast to the Nb micro-alloyed grade. This can be attributed to a contrary precipitation behaviour during welding.
KW - High-strength structural steel
KW - Gas metal arc welding
KW - HAZ-softening
KW - Microalloying influences
KW - Thermodynamic simulation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579988
DO - https://doi.org/10.1007/s40194-023-01550-2
SN - 0043-2288
SP - 1
EP - 10
PB - Springer
AN - OPUS4-57998
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Witte, Julien
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Stresses in repair welding of high-strength steels—part 1: restraint and cold cracking risk
N2 - AbstractThe sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures, like mobile or ship cranes. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of global and local welding-induced stresses may lead to crack formation and component failure, particularly in interaction with the degradation of the microstructure and mechanical properties of high-strength steels during the repair process. However, manufacturers hardly have any information about these issues and there is a lack of recommendations and guidelines to take these safety-relevant aspects into account in adequate repair concepts. The aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines to avoid cold cracking, damage and expensive reworking especially for high-strength steels. Part 1 of this study involves systematic investigations of influences of shrinkage restraint during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures. The quantification of the shrinkage restraint of repair weld joints was achieved by means of experimental and numerical restraint intensity analysis. In welding experiments with self-restrained slot specimens, restraint intensity and introduction of hydrogen via the welding arc using anti spatter spray were varied systematically to analyse the effect on welding result, residual stresses and cold cracking. It could be shown that increasing restraint intensities result in significantly higher transverse residual stress levels. In the case of hydrogen introduction S500MLO showed no cold cracking independent of the restraint conditions. However, S960QL was found to be considerably cold cracking sensitive if hydrogen is introduced. With increasing restraint intensity length and number of cold cracks increases significantly. Part 2 [1] of this study is focussed on microstructure and residual stresses due to gouging and stress optimization via adequate heat control parameters in repair welding.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595212
DO - https://doi.org/10.1007/s40194-024-01691-y
SN - 0043-2288
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-59521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Nina
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Influence of microalloying on precipitation behavior and notch impact toughness of welded high‑strength structural steels
N2 - Microalloying elements such as Nb and Ti are essential to increase the strength of quenched and tempered high-strength low alloy (HSLA) structural steels with nominal yield strength ≥ 690 MPa and their welded joints. Standards such as EN 10025–6 only specify limits or ranges for chemical composition, which leads to variations in specific compositions between steel manufacturers. These standards do not address the mechanical properties of the material, and even small variations in alloy content can significantly affect these properties. This makes it difficult to predict the weldability and integrity of welded joints, with potential problems such as softening or excessive hardening of the heat-affected zone (HAZ). To understand these metallurgical effects, previous studies have investigated different microalloying routes with varying Ti and Nb contents using test alloys. The high-strength quenched and tempered fine-grained structural steel S690QL is the basic grade regarding chemical composition and heat treatment. To evaluate weldability, three-layer welds were made using high-performance MAG welding. HAZ formation was investigated, and critical microstructural areas were identified, focusing on phase transformations during cooling and metallurgical precipitation behavior. Isothermal thermodynamic calculations for different precipitations were also carried out. Mechanical properties, especially Charpy notch impact toughness, were evaluated to understand the influence of different microalloys on the microstructure of the HAZ and mechanical properties.
KW - High-strength structural steel
KW - Gas metal arc welding
KW - HAZ-softening
KW - Notch impact toughness
KW - Microalloying influences
KW - Thermodynamic simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608548
DO - https://doi.org/10.1007/s40194-024-01827-0
SN - 0043-2288
SP - 1
EP - 13
PB - Springer
AN - OPUS4-60854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Gornushkin, Igor B.
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
A1 - Treutler, Kai
A1 - Wesling, Volker
T1 - In situ chemical analysis of duplex stainless steel weld by laser induced breakdown spectroscopy
N2 - The high corrosion resistance and good mechanical properties of duplex stainless steel (DSS) are due to its special chemical composition, which is a balanced phase ratio of ferrite (α) and austenite (γ). Many industrial applications require the integration of DSS components. For this, Gas tungsten arc welding (GTAW) is an excellent choice, as it allows an automated operation with high reproducibility. However, when the weld pool solidifies, critical ratios of α- and γ- phases can occur, which lead to solidification cracking, increased susceptibility to corrosion, and a decrease in ductility and critical strength. Previous studies have shown that these defects can be caused by the accumulation of manganese and chromium in the heat affected zone (HAZ), requiring ongoing monitoring of this accumulation. A suitable method for such monitoring is laser-induced breakdown spectroscopy (LIBS), which can be used in two operating modes: calibration using standard reference samples and calibration-free. Unlike conventional quantitative LIBS measurements, which require reference samples to generate a calibration curve, calibration-free LIBS (CF-LIBS) allows chemical compositions to be determined solely from the emission spectrum of the plasma. Numerous publications show that CF-LIBS is a fast and efficient analytical method for the quantitative analysis of metal samples. In this work, CF-LIBS is applied to spectra obtained during GTAW DSS welding and the result is compared with those obtained by PLS analysis. A good correlation was found between both types of analysis, demonstrating the suitability of the CF-LIBS method for this application. The CF-LIBS method has a significant advantage over conventional LIBS due to the rapid in situ measurement of concentrations of major alloying elements without calibration procedure. This, combined with fast feedback and appropriate adjustment of welding parameters, helps prevent welding defects.
KW - Duplex stainless steels
KW - In situ measurement
KW - LIBS
KW - GMAW
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597940
DO - https://doi.org/10.1016/j.sab.2024.106899
SN - 0584-8547
VL - 214
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-59794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Willeke, Maraike
A1 - Giese, Marcel
A1 - Lorenz, Swenja
A1 - Treutler, Kai
A1 - Schröpfer, Dirk
A1 - Wesling, Volker
A1 - Kannengießer, Thomas
T1 - Effect of alloy modification on the wear protection coatings made of Ni- and Co-based materials and surface machinability via ultrasonic milling process
N2 - AbstractWear-resistant coatings are required for highly efficient and economical steel components in equipment, process, and power plant engineering to withstand high corrosive, tribological, thermal, and mechanical stresses. Co-alloys are used as wear-resistant coatings for steel components, tailored to the specific application. The substitutability of Co alloys with Ni-based wear protection systems, in addition to price and supply uncertainties, is facilitated by the combination of innovative welding and machining processes such as ultrasonic-assisted milling. The aim of the study is to improve the machinability of two different hard-facing alloys while maintaining the same wear protection potential. Therefore, the wear-resistant alloys NiMoCrSi (Colmonoy C56) and CoMnCrSi (Tribaloy T400) were modified by the alloying additions Nb, Hf, and Ti and then applied to a carbon-manganese steel S355 using the plasma transfer arc (PTA) welding process. The influence of the alloying additions on the microstructure as
KW - Wear resistance
KW - Co-based alloy
KW - Ni-based alloy
KW - PTA welding process
KW - Ultrasonic assisted milling process
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623931
DO - https://doi.org/10.1007/s00170-024-14955-0
SN - 0268-3768
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-62393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Westin, Elin Marianne
A1 - Griesche, Axel
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
A1 - Treutler, Kai
A1 - Wesling, Volker
A1 - Wessman, Sten
T1 - Assessing ferrite content in duplex stainless weld metal: WRC ‘92 predictions vs. practical measurements
N2 - AbstractThe weldability of stainless steels is largely controlled by the chemical composition, and alloys with ferritic or ferritic-austenitic solidification show the highest resistance to hot cracking. As the resulting phase balance also affects the final properties, it may be beneficial to both foresee and measure the weld metal ferrite content. The WRC ‘92 constitution diagram is currently the most accurate prediction tool available, but it does not take the cooling rate into consideration and the precision may be less accurate for stainless steels with high ferrite numbers (FNs). This study aims to assess the reliability of the WRC ‘92 diagram for weld metals with FN 50. The chemical composition was altered through gas tungsten arc welding (GTAW) of UNS S32205 with ER347 filler wire that had been coated using physical vapor deposition (PVD) with either niobium (Nb), copper (Cu), nickel (Ni), manganese (Mn), carbon (C), or silicon (Si). The actual ferrite content was evaluated using image analysis, FeriteScope and X-ray diffraction (XRD). While predictions from the WRC ‘92 diagram were deemed acceptable for Ni, Si, and Mn, notable deviations were observed for Nb, Cu, and C. The FeriteScope exhibited a consistent trend with image analysis, albeit with slightly higher FN values, wider scatter, and the conversion factor from FN to vol% is open for discussion. The lowest accuracy and largest spread were obtained using non-contact XRD, rendering it unsuitable for ferrite measurements of welds. These findings underscore the need for improved prediction tools and appropriate measurement methods for assessing ferrite content in duplex weld metals.
KW - Duplex stainless steel
KW - Welding
KW - Phase balance
KW - Microscopy
KW - Microstructure
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618777
DO - https://doi.org/10.1007/s40194-024-01878-3
SN - 1878-6669
VL - 69
IS - 1
SP - 31
EP - 45
PB - Springer
CY - Berlin
AN - OPUS4-61877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Westin, Elin Marianne
A1 - Griesche, Axel
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
A1 - Treutler, Kai
A1 - Wesling, Volker
A1 - Wessman, Sten
T1 - Assessing ferrite content in duplex stainless weld metal: WRC ‘92 predictions vs. practical measurements
N2 - AbstractThe weldability of stainless steels is largely controlled by the chemical composition, and alloys with ferritic or ferritic-austenitic solidification show the highest resistance to hot cracking. As the resulting phase balance also affects the final properties, it may be beneficial to both foresee and measure the weld metal ferrite content. The WRC ‘92 constitution diagram is currently the most accurate prediction tool available, but it does not take the cooling rate into consideration and the precision may be less accurate for stainless steels with high ferrite numbers (FNs). This study aims to assess the reliability of the WRC ‘92 diagram for weld metals with FN 50. The chemical composition was altered through gas tungsten arc welding (GTAW) of UNS S32205 with ER347 filler wire that had been coated using physical vapor deposition (PVD) with either niobium (Nb), copper (Cu), nickel (Ni), manganese (Mn), carbon (C), or silicon (Si). The actual ferrite content was evaluated using image analysis, FeriteScope and X-ray diffraction (XRD). While predictions from the WRC ‘92 diagram were deemed acceptable for Ni, Si, and Mn, notable deviations were observed for Nb, Cu, and C. The FeriteScope exhibited a consistent trend with image analysis, albeit with slightly higher FN values, wider scatter, and the conversion factor from FN to vol% is open for discussion. The lowest accuracy and largest spread were obtained using non-contact XRD, rendering it unsuitable for ferrite measurements of welds. These findings underscore the need for improved prediction tools and appropriate measurement methods for assessing ferrite content in duplex weld metals.
KW - Duplex stainless steel
KW - Phase fraction prediction
KW - WRC diagram
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623682
DO - https://doi.org/10.1007/s40194-024-01878-3
VL - 69
SP - 31
EP - 45
PB - Springer Science and Business Media LLC
AN - OPUS4-62368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giese, Marcel
A1 - Gräbner, Maraike
A1 - Schröpfer, Dirk
A1 - Treutler, Kai
A1 - Lorenz, Svenja
A1 - Kannengießer, Thomas
A1 - Wesling, Volker
T1 - Alloy modification and ultrasonic-assisted milling of wear-resistant alloys with defined surfaces
N2 - The reduction of CO2 emissions is closely linked to the development of highly efficient and economical steel components in plant and process engineering. To withstand the high combined corrosive, tribological, thermal, and mechanical stresses, wear-resistant coatings tailored to the application and steel grade are used. In addition to the increasing demand to substitute conventional cobalt alloys with nickel alloys, there is also a growing need for defined or functional surfaces of high integrity. Due to high tool wear, milling operations required to produce the complex geometries of the components are often not economically feasible for SMEs. By means of alloy modification of the filler metals for nickel-based plasma build-up welded wear-resistant coatings and by the use of innovative ultrasonic-assisted milling processes more favourable machinability shall be achieved without reducing the wear protection potential. In this paper, the influence of the microstructure and precipitation morphology adjusted by means of alloy modification on the machinability is investigated. This is done based on a wear protection alloy NiCrMoSiFeB (trade name: Colmonoy 56 PTA) typically used for screw machines, which substitutes conventional CoCr alloys (Stellite). Metallurgical investigations and in-situ measurements of occurring process forces and temperatures at the tool cutting edge during milling as well as subsequent investigations of tool wear and surface integrity allow a detailed analysis and correlation between microstructural properties and machinability. For the cast samples, a clear change in the microstructure and hardness can be seen through the addition of Al, Ti, or Nb. These differences lead to an improvement in the machining process for Nb. Al and Ti cause long-needled or star-shaped precipitations and hardness increases, which lead to higher cutting forces and increased tool wear.
KW - Cladding
KW - Wear resistant alloys
KW - Alloy modification
KW - Post-processing
KW - Ultrasonic assisted milling
KW - Renewable energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622918
DO - https://doi.org/10.1007/s40194-024-01786-6
SN - 1878-6669
VL - 68
SP - 2567
EP - 2575
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-62291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liepold, Philipp
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Transvarestraint testing of high-strength steel filler metal
N2 - High-strength steel welds are typically not known to be susceptible to Solidification Cracking (SC). However, modern light-weight constructions may force welding in highly restrained conditions, which are known to increase the probability of Solidification Crack (SC) emergence. In this article, the Modified Varestraint-Transvarestraint (MVT) test was used to evaluate the hot cracking susceptibility of welds made from high-strength, low-alloyed filler material. The materials tested include solid wires and a metal-cored wire. All wires are typically used in the Gas Metal Arc Welding (GMAW) process. Susceptibility to SC was measured over a wide range of welding parameters and bending speeds. Results show little affinity of the tested materials to SC. However, crack length increases in most cases with arc energy ( U ∙ I∕welding speed ) and welding speed. The length of the longest crack in one test specimen follows a similar trend until high welding speeds, where stagnation of crack length with changing arc energy was observed.
KW - MVT
KW - Varestraint
KW - Transvarestraint
KW - Solidification cracking
KW - High-strength steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630084
DO - https://doi.org/10.1007/s40194-025-02042-1
SN - 1878-6669
VL - 2025
SP - 1
EP - 12
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-63008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berkes, L.
A1 - Nehring, Grzegorz
A1 - Bonnerot, O.
A1 - Krutzsch, M.
A1 - Rabin, Ira
A1 - Richter, T. S.
T1 - Mixed Inks in Two Coptic Documents from the Hermopolite Region Relating to Lease Business
N2 - In this article, we present two Coptic papyri, P 11934 and P 11935 from the Berlin collection excavated in Ashmunein (ancient Hermopolis) by Otto Rubensohn in 1906. We employ a multi-disciplinary approach that takes into account both their materiality – writing support as well as ink – and their content, as has become ‘best practice’. 1 Material aspects of written documents have traditionally been the purview of papyrologists. Recently developed methods of scientific analysis generate sets of archaeometric data with the potential to improve understanding of the materiality of ancient document production, as well as to yield new evidence for genuine papyrological research questions. To achieve this, a large corpus of comparative data needs to be built. Our contribution offers a first step in this direction. We aim at presenting the papyri, which were selected because of the ink corrosion during conservation work at the Berlin collection, in a format that is exhaustive both for material and textual aspects. The inks from both papyri were analysed using a combination of techniques, contributing to our better understanding of the development of ink technology in Late Antiquity.
KW - Coptic papyri
KW - Methods of scientific analysis
KW - Sets of archaeometric data
KW - Mixed Inks
KW - Ink corrosion
KW - Ancient document production
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579948
DO - https://doi.org/10.48631/pylon.2023.3.98234
SN - 2751-4722
VL - 2023/3
IS - 3
SP - 1
EP - 18
PB - Ceative Commons Attribution ShareAlike
CY - Heidelberg, Germany
AN - OPUS4-57994
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghigo, Tea
A1 - Rabin, Ira
A1 - Buzi, P.
T1 - Black Egyptian inks in Late Antiquity: new insights on their manufacture and use
N2 - We present here our methodological approach applied to the study of Egyptian inks in Late Antiquity. It is based on an interdisciplinary strategy, bringing together a variety of disciplines from humanities and natural sciences, and it aims at systematically collecting a statistically relevant amount of data regarding the composition of the inks. The application of a wellestablished, non-invasive protocol that includes near-infrared imaging and X-ray fluorescence spectroscopy for in situ measurements enables the identification and characterisation of inks dating from the end of Late Antiquity onwards. However, sometimes this method limits our understanding when characterising more ancient inks. Trying to overcome these limitations, the potential of a new device for the characterisation of organic compounds is here explored by conducting preliminary tests on mock samples.
In this work, we present the results from 77 codicological units that include some of the earliest manuscripts of our corpus that presently lists 159 units.
KW - Ink
KW - Archaeometry
KW - Manuscripts
KW - Coptic
KW - Egypt
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503893
DO - https://doi.org/10.1007/s12520-019-00977-3
VL - 12
IS - 3
SP - 1
EP - 14
PB - Springer
AN - OPUS4-50389
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Bonnerot, Olivier
A1 - Gordon, N.
A1 - Rabin, Ira
T1 - Writing and Correcting a Torah Scroll in Germany of the Thirteenth and Fourteenth Centuries
N2 - Scientific material analysis of the elemental composition of inks from different strata of a manuscript has the potential to complement scholarly observations using palaeography and philology in reconstructing the history of the manuscript’s production, correction and repair.
There are three typologically different classes of black writing inks: soot inks consist of carbon particles.
KW - Manuscript studies
KW - Hebrew studies
KW - Ink analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540658
DO - https://doi.org/10.25592/uhhfdm.9749
VL - Comparative Oriental Manuscript Studies Bulletin 7, 2021
IS - 7
SP - 2
EP - 20
PB - Centre for the study of manuscript cultures
CY - Hamburg
AN - OPUS4-54065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Girard, Solène
A1 - Rabin, Ira
T1 - Conservation and Technical Evaluation of an Early Medieval Papyrus Codex
N2 - In 2005, a team of Polish archaeologists discovered three Coptic codices, two on papyrus and one on parchment, in the rubbish dump of a hermitage at Sheik Abd el-Gurna, Egypt. While the parchment codex and the remains of the bindings of the papyrus ones have been conserved, the text blocks of the papyrus codices were opened and disassembled and after being disinfected remained untouched for nearly 15 years, until the current project started. Currently, all three books are stored in the collection of the Coptic Museum in Cairo. Our team undertook the conservation of and archaeometric research on the papyrus codices. The first of the books contains the Canons of Pseudo-Basil, while the second is an Encomium of St. Pisenthios. Both codices have been palaeographically dated to the seventh-eighth centuries CE. In this paper, we describe our project and present the results of the work carried out on the Canons of Pseudo-Basil. Our work involved photography in transmitted light, measurements of the thickness of the papyrus leaves, and digital microscopy under three-light illumination. These measurements allowed us to determine the types of the inks and characterize the papyrus writing substrate. For conservation, we used a novel method developed in the Egyptian Museum in Berlin that comprises suspending papyrus folios on a translucent, extremely thin Japanese paper inside glass frames without the use of adhesives.In 2005, a team of Polish archaeologists discovered three Coptic codices, two on papyrus and one on parchment, in the rubbish dump of a hermitage at Sheik Abd el-Gurna, Egypt. While the parchment codex and the remains of the bindings of the papyrus ones have been conserved, the text blocks of the papyrus codices were opened and disassembled and after being disinfected remained untouched for nearly 15 years, until the current project started. Currently, all three books are stored in the collection of the Coptic Museum in Cairo. Our team undertook the conservation of and archaeometric research on the papyrus codices. The first of the books contains the Canons of Pseudo-Basil, while the second is an Encomium of St. Pisenthios. Both codices have been palaeographically dated to the seventh-eighth centuries CE. In this paper, we describe our project and present the results of the work carried out on the Canons of Pseudo-Basil. Our work involved photography in transmitted light, measurements of the thickness of the papyrus leaves, and digital microscopy under three-light illumination. These measurements allowed us to determine the types of the inks and characterize the papyrus writing substrate. For conservation, we used a novel method developed in the Egyptian Museum in Berlin that comprises suspending papyrus folios on a translucent, extremely thin Japanese paper inside glass frames without the use of adhesives.
KW - Papyrus
KW - Codex
KW - Conservation
KW - Iron gall ink
KW - Coptic
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570998
DO - https://doi.org/10.1080/00393630.2023.2183554
SN - 0039-3630
SP - 1
EP - 12
PB - Taylor & Francis
AN - OPUS4-57099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Bonnerot, Olivier
A1 - Gerhardt, M.
A1 - Krutzsch, M.
A1 - Rabin, Ira
T1 - Looking for the missing link in the evolution of black inks
N2 - In the transition from carbon to iron-gall inks, the two documents from the Egyptian Museum and Papyrus Collection in Berlin with shelfmarks P 13500 and P 13501 discussed in this work present an important case. Their inks appear brownish, although they date back to the fourth and third century BCE, when carbon inks are believed to have been commonly if not exclusively used. Using imaging micro-X-ray fluorescence and infrared reflectography, we discovered that the inks in both documents contain a significant amount of copper in addition to carbon. Comparing the extant recipes for black writing inks and the experimental evidence, we suggest that these inks are a transition between the pure carbon and the iron-gall inks. Such inks may have been quite common before the production of iron-gall ink was clearly understood and established.
KW - Black writing ink
KW - Hellenistic
KW - Papyrus
KW - XRF imaging
KW - NIR imaging
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523708
DO - https://doi.org/10.1007/s12520-021-01320-5
VL - 13
IS - 4
SP - Article 71
PB - Springer
AN - OPUS4-52370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nehring, Grzegorz
A1 - Gordon, Nehemia
A1 - Rabin, Ira
T1 - Distinguishing between seemingly identical inks using scanning μXRF and heat maps
N2 - This study will present a new approach to distinguishing writing inks that have the same elemental compositions and visual appearances. The approach is based on displaying the intensity of elemental distributions as heat maps that represent data recorded with a scanning μX-ray fluorescence spectrometer. The heat maps present the data so as to facilitate digitally identifying and distinguishing between inks used to produce, correct, and reink two medieval Torah scrolls. As ritual objects, Torah scrolls had to be written in accordance with exacting standards that evolved over time. This requirement led to successive stages of modifications, sometimes over centuries. Both vitriolic and non-vitriolic inks used to modify Torah scrolls can be visually identical to each other. Furthermore, different non-vitriolic inks usually have an identical elemental composition. The solid material analysis evidence and its presentation as heat maps made it possible to discriminate between original and altered portions of text that in some cases would have been impossible. Our interdisciplinary work brought together conservation, material science, paleog-raphy, and philology to enable the identification of complex stratigraphy in multiple stages of production, correction, and reinking. ©2 0 2 2 Published by Elsevier Masson SAS.
KW - Spectroscopy
KW - Scanning micro-X-ray fluorescence
KW - Vitriolic iron-gall inks
KW - Non-vitriolic iron-gall inks
KW - Heat maps
KW - Torah scrolls
KW - Scribal corrections
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557271
DO - https://doi.org/10.1016/j.culher.2022.07.007
SN - 1296-2074
VL - 57
SP - 142
EP - 148
PB - Elsevier Masson SAS
AN - OPUS4-55727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Boaretto, E.
A1 - Newman, H.
A1 - Shevchuk, I.
A1 - Breterniz, S.
A1 - Rabin, Ira
T1 - Date, Materiality and Historical Significance of P.Köln Inv. 5941
N2 - The paper presents the results of the radiocarbon dating and ink analysis of a leather fragment bearing an important liturgical text in Hebrew from the early centuries of the common era. The work initiated by the scholarly interest in the text stresses the importance of the date and materiality of the manuscripts and closes with an appeal to the curators of manuscript collections.
KW - Mixed ink
KW - Radiocarbon
KW - Leather
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528063
DO - https://doi.org/10.25592/uhhfdm.8471
VL - 6/2
SP - 173
EP - 186
AN - OPUS4-52806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rabin, Ira
ED - Raggetti, L.
T1 - Material Studies of Historic Inks: Transition from Carbon to Iron-Gall Inks
N2 - This chapter offers observations and considerations concerning black writing inks encountered in writing supports transmitting documentary and literary texts of the late Antiquity and early Middle Ages. It discusses different types of inks, the Methods of their detection and their use in different times and geographical areas.
KW - Material analysis
KW - Writing inks
KW - Ink fingerprint
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528057
DO - https://doi.org/10.1163/9789004444805_006
SP - 70
EP - 78
PB - Brill
CY - Leiden
AN - OPUS4-52805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Rabin, Ira
A1 - Hahn, Oliver
ED - Michel, C.
ED - Friedrich, M.
T1 - Detection of Fakes: The Merits and Limits of Non-Invasive Materials Analysis
N2 - This paper addresses the sensitive issue of authenticating unprovenanced manuscripts of high monetary value to certify they are genuine. Over the last decade, the popularity of material studies of manuscripts using non-destructive testing (NDT) has increased enormously. These studies are held in especially high esteem in the case of suspicious writings due to the methodological rigour they are reputed to contribute to debate. We would like to stress that materials analysis alone cannot prove that an object is genuine. Unfortunately, audiences with a humanities background often tend to disregard the technical details and treat any published interpretation of instrumental analysis as an objective finding. Four examples are outlined here to illustrate what questionable contributions the natural sciences can make in describing manuscripts that have actually been forged.
KW - Fakes
KW - Non-invasive analysis
KW - Limitations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517202
SN - 978-3-11-071422-7
DO - https://doi.org/10.1515/9783110714333
SN - 2365-9696
VL - 20
SP - 281
EP - 290
PB - Walter de Gruyter GmbH
CY - Berlin/Boston
AN - OPUS4-51720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernegger, Raphael
A1 - Maierhofer, Christiane
A1 - Altenburg, Simon
T1 - Quantification of delaminations in semitransparent solids using pulsed thermography and mathematical 1D models
N2 - Material defects in fiber reinforced polymers such as delaminations can rapidly degrade the material properties or can lead to the failure of a component. Pulse thermography (PT) has proven to be a valuable tool to identify and quantify such defects in opaque materials. However, quantification of delaminations within semitransparent materials is extremely challenging. We present an approach to quantify delaminations within materials being semitransparent within the wavelength ranges of the optical excitation sources as well as of the infrared (IR) camera. PT experimental data of a glass fiber reinforced polymer with a real delamination within the material were reconstructed by one dimensional (1D) mathematical models. These models describe the heat diffusion within the material and consider semitransparency to the excitation source as well to the IR camera, thermal losses at the samples surfaces and a thermal contact resistance between the two layers describing the delamination. By fitting the models to the PT data, we were able to determine the depth of the delamination very accurately. Additionally, we analyzed synthetic PT data from a 2D simulation with our 1D-models to show how the thermal contact resistance is influenced by lateral heat flow within the material.
KW - Pulsed thermography
KW - Quantification
KW - Numerical simulation
KW - Analytical model
KW - Semitransparent
KW - GFRP
KW - Delamination
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505766
DO - https://doi.org/10.1007/s10765-020-02642-7
VL - 41
IS - 5
SP - Article number: 67
PB - Springer
AN - OPUS4-50576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Kannengießer, Thomas
A1 - Kromm, Arne
A1 - Hensel, J.
T1 - Influence of the WAAM process and design aspects on residual stresses in high-strength structural steels
N2 - Wire arc additive manufacturing (WAAM) enables the efficient production of weight-optimized modern engineering structures. Further increases in efficiency can be achieved by using high-strength structural steels. Commercial welding consumables for WAAM are already available on the market. Lack of knowledge and guidelines regarding welding residual stress and component safety during production and operation leads to severely limited use for industry applications. The sensitive microstructure of high-strength steels carries a high risk of cold cracking; therefore, residual stresses play a crucial role. For this reason, the influences of the material, the WAAM process, and the design on the formation of residual stresses and the risk of cold cracking are being investigated. The material used has a yield strength of over 800 MPa. This strength is adjusted via solid solution strengthening and a martensitic phase transformation. The volume expansion associated with martensite formation has a significant influence on the residual stresses. The focus of the present investigation is on the additive welding parameters and component design on their influence on hardness and residual stresses, which are analyzed by means of X-ray diffraction (XRD). Reference specimens (hollow cuboids) are welded fully automated with a systematic variation of heat control and design. Welding parameters and AM geometry are correlated with the resulting microstructure, hardness, and residual stress state. Increased heat input leads to lower tensile residual stresses which causes unfavorable microstructure and mechanical properties. The component design affects heat dissipation conditions and the intensity of restraint during welding and has a significant influence on the residual stress.
KW - DED-arc
KW - Additive manufacturing
KW - High-strength steel filler metal
KW - Residual stress
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572698
DO - https://doi.org/10.1007/s40194-023-01503-9
SN - 1878-6669
VL - 67
IS - 4
SP - 987
EP - 996
PB - Springer
CY - Berlin
AN - OPUS4-57269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Oster, Simon
A1 - Altenburg, Simon
A1 - Metz, C.
A1 - Maierhofer, Christiane
T1 - Aktive Laserthermografie im L-PBF-Prozess zur in-situ Detektion von Defekten
N2 - Die zerstörungsfreie Prüfung von metallischen Bauteilen hergestellt mit additiver Fertigung (Additive Manufacturing - AM) gewinnt zunehmend an industrieller Bedeutung. Grund dafür ist die Feststellung von Qualität, Reproduzierbarkeit und damit auch Sicherheit für Bauteile, die mittels AM gefertigt wurden. Jedoch wird noch immer ex-situ geprüft, wobei Defekte (z.B. Poren, Risse etc.) erst nach Prozessabschluss entdeckt werden. Übersteigen Anzahl und/oder Abmessung die vorgegebenen Grenzwerte für diese Defekte, so kommt es zu Ausschuss, was angesichts sehr langer Bauprozessdauern äußerst unrentabel ist. Eine Schwierigkeit ist dabei, dass manche Defekte sich erst zeitverzögert zum eigentlichen Materialauftrag bilden, z.B. durch thermische Spannungen oder Schmelzbadaktivitäten. Dementsprechend sind reine Monitoringansätze zur Detektion ggf. nicht ausreichend.
Daher wird in dieser Arbeit ein Verfahren zur aktiven Thermografie an dem AM-Prozess Laser Powder Bed Fusion (L-PBF) untersucht. Das Bauteil wird mit Hilfe des defokussierten Prozesslasers bei geringer Laserleistung zwischen den einzelnen gefertigten Lagen unabhängig vom eigentlichen Bauprozess erwärmt. Die entstehende Wärmesignatur wird ort- und zeitaufgelöst durch eine Infrarotkamera erfasst. Durch diese der Lagenfertigung nachgelagerte Prüfung werden auch zum Bauprozess zeitversetzte Defektbildungen nachweisbar.
In dieser Arbeit finden die Untersuchungen als Proof-of-Concept, losgelöst vom AM-Prozess, an einem typischen metallischen Testkörper statt. Dieser besitzt eine Nut als oberflächlichen Defekt. Die durchgeführten Messungen finden an einer eigens entwickelten L-PBF-Forschungsanlage innerhalb der Prozesskammer statt. Damit wird ein neuartiger Ansatz zur aktiven Thermografie für L-PBF erforscht, der eine größere Bandbreite an Defektarten auffindbar macht. Der Ansatz wird validiert und Genauigkeit sowie Auflösungsvermögen geprüft. Eine Anwendung am AM-Prozess wird damit direkt forciert und die dafür benötigten Zusammenhänge werden präsentiert.
T2 - DGZfP-Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Thermografie
KW - Zerstörungsfreie Prüfung
KW - Aktive Laserthermografie
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550353
SN - 978-3-947971-25-1
VL - 177
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V.
AN - OPUS4-55035
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalska, Karina
A1 - Heiermann, Monika
A1 - Lühr, Carsten
A1 - Meermann, Björn
A1 - Pecenka, Ralf
A1 - Schulz, Andreas
A1 - Langhammer, Nicole
A1 - Theuerl, Susanne
A1 - Prochnow, Annette
T1 - Potentials of typical plant species from rewetted fenlands for the supply of strategic elements
N2 - Rewetting of peatlands requires the development of new biomass utilization pathways. The supply of strategic elements with key importance for the development of priority technologies, such as germanium (Ge), silicon (Si) and rare earth elements, from fenland plants is one option. To provide a first estimation of the potential, concentrations of strategic elements were determined in nine biomass samples covering typical fenland vegetation in northeast Germany. Subsequently, a simplified estimation of potential revenue from strategic element recovery was made. The analysed plant species can be classified as high or intermediate Si plant accumulators with highest contents of more than 16.0 g Si kg−1 dry mass (DM) in sedges and common reeds. Ge concentrations were lower with reed canary grass containing the highest amounts of 465.3 µg Ge kg−1 DM. Simultaneous acquisition of Ge and Si could provide higher total element yields and revenues of up to 500 $ ha−1. In contrast, the potentials for supplying rare earth elements appeared to be very low, with common reed containing the highest sum of rare earth elements of 437.4 µg kg−1 DM. Biomass from rewetted fenlands is capable of accumulating strategic elements. More knowledge is required to understand the factors affecting their accumulation.
KW - Recycling
KW - Fenlands
KW - Strategic elements
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635631
DO - https://doi.org/10.1038/s41598-025-05180-0
SN - 2045-2322
VL - 15
IS - 1
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-63563
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Reichel, Levin
A1 - Kromm, Arne
A1 - Michael, Thomas
A1 - Schroepfer, Dirk
A1 - Kannengiesser, Thomas
T1 - Modern welding processes for optimizing repair welding on high-strength offshore steels
N2 - The successful energy transition in Germany will require offshore wind turbines with outputs >10 MW in the future, for which high-strength steels with a yield strength of up to 500 MPa and wall thicknesses up to 150 mm are increasingly being used. The repair of weld seams when detecting defects during NDT requires localized gouging and rewelding. This involves high demands on welding manufacturing, especially for highstrength steels. Due to a lack of investigations, there are no repair concepts and information in standards and guidelines, particularly for high-strength thick plate joints made of high-strength offshore steels. However, these are urgently needed to enable processors, especially SMEs, to carry out safe and economical repairs. Therefore, BAM startedthe FOSTA project P1629 (IGF 01IF22746N) to investigate the stress-optimized repair(local gouging and welding) of high-strength thick plate joints made of offshore grades in the yield strength range off 355 to 460 MPa and similar weld metal with controlled high-performance GMAW processes and optimized narrower gouging grooves. The experimental analyses consider the complex interaction of material, process, and designrelated influences on the formation of weld-related stresses and the special microstructure of high-strength fine-grain structural steels. Welding-related material Degradation and crack-critical residual tensile stresses need to be avoided to ensure high component safety and performance. With component-related welding experiments on special testing equipment, adapted process and heat control concepts along with variable groove configurations will be developed and recommendations for guidelines elaborated. This is the prerequisite for fully utilizing the strength potential of high-strength steels and making a valuable contribution to the energy transition in Germany, especially for steelprocessing SMEs.
T2 - 6. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - Narrow groove
KW - Optimized repair welding
KW - Modern welding processes
KW - High-strength steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636520
DO - https://doi.org/10.21268/20250507-5
SP - 3
EP - 15
AN - OPUS4-63652
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Łojewska, J.
A1 - Rabin, Ira
A1 - Pawcenis, D.
A1 - Bagniuk, J.
A1 - Aksamit-Koperska, M.-A.
A1 - Sitarz, M.
A1 - Missori, M.
A1 - Krutzsch, M.
T1 - Recognizing ancient papyri by a combination of spectroscopic, diffractional and chromatographic analytical tools
N2 - Ancient papyri are a written heritage of culture that flourished more than 3000 years ago in Egypt. One of the most significant collections in the world is housed in the Egyptian Museum and Papyrus Collection in Berlin, from where the samples for our investigation come. The papyrologists, curators and conservators of such collections search intensely for the analytical detail that would allow ancient papyri to be distinguished from modern fabrications, in order to detect possible forgeries, assess papyrus deterioration state, and improve the design of storage conditions and conservation methods. This has become the aim of our investigation. The samples were studied by a number of methods, including spectroscopic (FTIR, fluorescent-FS, Raman) diffractional (XRD) and chromatographic (size exclusion chromatography-SEC), selected in order to determine degradation parameters: overall oxidation of lignocellulosic material, degree of polymerization and crystallinity of cellulose. The results were correlated with those obtained from carefully selected model samples including modern papyri and paper of different composition aged at elevated temperature in humid air. The methods were classified in the order SEC > FS > FTIR > XRD, based on their effectiveness in discriminating the state of papyri degradation. However, the most trustworthy evaluation of the age of papyri samples should rely on several methods.
KW - Archaeometry
KW - FTIR
KW - XRD
KW - Raman
KW - Chromatography
KW - Papyrology
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428704
DO - https://doi.org/10.1038/srep46236
SN - 2045-2322
VL - 7
SP - 46236, 1
EP - 46236, 12
AN - OPUS4-42870
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schütz, Roman
A1 - Bertinetti, L.
A1 - Rabin, Ira
A1 - Fratzl, P.
A1 - Masic, A.
T1 - Quantifying degradation of collagen in ancient manuscripts: the case of the Dead Sea Temple Scroll
N2 - Since their discovery in the late 1940s, the Dead Sea Scrolls, some 900 ancient Jewish texts, have never stopped attracting the attention of scholars and the broad public alike, because they were created towards the end of the Second Temple period and the 'time of Christ'. Most of the work on them has been dedicated to the information contained in the scrolls' text, leaving physical aspects of the writing materials unexamined. They are, however, crucial for both historical insight and preservation of the scrolls. Although scientific analysis requires handling, it is essential to establish the state of degradation of these valued documents. Polarized Raman Spectroscopy (PRS) is a powerful tool for obtaining information on both the composition and the level of disorder of molecular units. In this study, we developed a non-invasive and non-destructive methodology that allows a quantification of the disorder (that can be related to the degradation) of protein molecular units in collagen fibers. Not restricted to collagen, this method can be applied also to other protein-based fibrous materials such as ancient silk, wool or hair. We used PRS to quantify the degradation of the collagen fibers in a number of fragments of the Temple Scroll (11Q19a). We found that collagen fibers degrade heterogeneously, with the ones on the surface more degraded than those in the core.
KW - Dead Sea Scrolls
KW - Collagen
KW - Raman spectroscopy
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331769
DO - https://doi.org/10.1039/c3an00609c
SN - 0003-2654
SN - 1364-5528
VL - 138
IS - 19
SP - 5594
EP - 5599
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-33176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Cohen, Zina
A1 - Olszowy-Schlanger, Judith
A1 - Hahn, Oliver
A1 - Rabin, Ira
ED - Wandrey,
T1 - Composition analysis of writing materials in Geniza fragments
N2 - Our current projects focus on the material analysis of the writing materials
kept in the Taylor-Schechter Collection at Cambridge University Library,
which houses the largest collection of Cairo Geniza fragments, about 190,000.
Although Geniza manuscripts have attracted a great deal of scholarly attention,
the material aspects of these documents seem to have been largely neglected.
The current study aims to obtain information on the composition of the writing
supports and the inks that were used, the production of the original manuscripts
and the history of their degradation. The collected data should supplement the
description based on Hebrew palaeography and codicology. Moreover, a characterisation
of the writing materials would provide insights on trade, local production
techniques and social structures. The tabulated results have the potential to
be used as geo-chronological markers if sufficient data is collected.
For our study, we chose Hebrew legal documents and letters from three communities
that co-existed in Fustat (today Cairo) in the 11th century: the Jerusalemite
(or ‘Palestinian’) community, the Babylonian community and the Karaites, three
different communities with different scribal traditions. In addition to this, we
studied non-biblical scrolls attributed to the Palestinian and Babylonian communities.
The question we addressed was whether we can correlate the use of a
specific type of ink to an objective criterion.
For our analysis at Cambridge University Library, we used a number of protocols
developed at BAM (Bundesanstalt für Materialforschung und -prüfung) in
Berlin and at the Centre for Study of Manuscript Cultures, University of Hamburg
(CSMC). These include reflectographic examination followed by non-destructive
X-ray fluorescence (XRF) analysis using transportable instruments so that the
analysis can be carried out in situ.
We have illustrated our approach here by providing two examples. The first one
describes our investigation of the leather fragment containing a portion of the
Babylonian Talmud on its hair side (TS Misc.26.53.17). The second example illustrates
our ability to compare iron-gall inks using the XRF method. In this case,
we explored the question of the codicological attribution of three fragments (TS
F17.4, TS 12.755 and TS 12.756) to the same Talmud manuscript.
KW - Cairo Genizah
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435590
DO - https://doi.org/10.1515/9783110546422-013
VL - 13
SP - 323
PB - de Gruyter
CY - Berlin
AN - OPUS4-43559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabin, Ira
A1 - Gordon, Nehemia
A1 - Calvillo, Nelson
T1 - Coloured Ruling Lines in a Fourteenth-Century Ashkenazi Torah Scroll
N2 - Rabbinic halakhah required that Torah scrolls be written with relief ruling, horizontal and vertical lines scored into the writing surface. Coloured ruling with plummet or ink would make a Torah scroll invalid for liturgical use. Ruling lines on some leather fragments of early Oriental Torah scrolls give the impression of being produced with plummet or ink but may be the result of dust in the furrows of relief ruling. Erfurt 9, a fourteenth-century Ashkenazi Torah scroll, has coloured ruling, which is partial secondary re-ruling, on 13 of the 34 surviving sheets, perhaps added when the original relief ruling was difficult to see. The coloured ruling in Erfurt 9 is brown, giving it the visual appearance of iron-gall ink. However, XRF tests showed that the only meaningful metallic component in the coloured ruling was lead (Pb). Lead plummet ruling tends to have a greyish appearance. Black specks under near infrared light are consistent with minium, a lead-based red ink that can turn brown when it degrades. Partial secondary re-ruling added with minium to the original relief ruling comes as a surprise as it would have rendered Erfurt 9 unfit for liturgical use.
KW - Hebrew Manuscripts
KW - Ruling Lines
KW - Coloured Ink
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628531
DO - https://doi.org/10.25592/uhhfdm.17169
SN - 2410-0951
VL - 10
SP - 9
EP - 32
AN - OPUS4-62853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Vehicle Dynamics and Train‑Induced Ground Vibration—Theoretical Analyses and Simultaneous Vehicle, Track, and Soil Measurements
N2 - Ground vibrations near railway lines are generated by the forces that are acting between wheel and rail. It seems to be a straight forward assumption that the vehicle dynamics are important for the level and the frequencies of the excitation forces. Different vehicle dynamics phenomena are analysed for their role in the excitation of ground vibrations: rigid body modes of the bogies, elastic (bending) modes of the car body, and elastic modes of the wheelset. The theoretical analyses use rigid body models, simplified elastic models, and detailed elastic models. Some of these problems are vehicle–track interaction problems where 3D finite‑element boundary‑element models have been used for the track and soil. It is shown that the rigid or flexible vehicle modes are well in the frequency range of ground vibrations (4 to 100 Hz). They have an influence on the excitation force but the additional forces are rather small and can be neglected in ground vibration prediction. The theoretical results are checked by experimental results of a simultaneous measurement of vehicle,
track, and ground vibrations.
KW - Rigid vehicle model
KW - Flexible car body
KW - Flexible wheelset
KW - Dynamic loads
KW - Ground vibration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569796
DO - https://doi.org/10.3390/vehicles5010013
VL - 5
IS - 1
SP - 223
EP - 247
PB - MDPI
CY - Basel
AN - OPUS4-56979
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhuang, Yiling
A1 - Haderlein, Stefan B.
A1 - Lutze, Holger V.
A1 - Sun, Chen
A1 - Fink, Friedrich
A1 - Paul, Andrea
A1 - Spahr, Stephanie
T1 - Persulfate activation by biochar for trace organic contaminant removal from urban stormwater
N2 - Persistent and mobile trace organic contaminants (TrOCs) in urban stormwater are difficult to remove through sedimentation- or sorption-based treatment and pose a risk to aquatic ecosystems and drinking water supplies. We demonstrate that the chemical oxidant peroxydisulfate (PDS) can be activated by shrimp shell biochar at pH 7 to form reactive species that selectively react with widespread stormwater contaminants. Of 11 TrOCs tested, oxidative transformation was observed for 1,3-diphenylguanidine, 2-hydroxybenzothiazole, 1H-benzotriazole, 5-methyl-benzotriazole, and diuron during water treatment with biochar and PDS. Laboratory batch experiments conducted with street runoff and a synthetic water showed that the water matrix, containing up to 7.5 mg L-1 dissolved organic carbon and 100 mM chloride, had a minor effect on the formation of reactive species and contaminant transformation. Using a set of scavengers and probe compounds, we provide evidence for singlet oxygen (1O2) as the predominant reactive species in the biochar/PDS system, which is in agreement with the selectivity of the process to oxidize electron-rich organic contaminants. The results of our study inform new strategies for stormwater treatment using heterogeneous oxidation processes for the abatement of persistent and mobile organic contaminants.
KW - Stormwater treatment
KW - Oxidation processes
KW - Pyrogenic carbon
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637952
DO - https://doi.org/10.1016/j.watres.2025.123921
SN - 0043-1354
VL - 284
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-63795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Skłodowska, Anna
A1 - Parolai, S.
A1 - Petrovic, B.
A1 - Romanelli, F.
T1 - Soil-structure interaction assessment combining deconvolution of building and field recordings with polarization analysis: application to the Matera (Italy) experiment
N2 - In this study, the wavefield radiated from a building to its surroundings is identified and extracted from M4.6 earthquake recordings collected by sensors installed in a building and on the nearby athletic field in Matera (Italy) using a new approach for soil-structure interaction assessment. The proposed approach for earthquake data analysis combines in an innovative way two methods already used in seismology and engineering seismology: deconvolution and polarization analysis. The approach enables the identification, reconstruction, and characterization of the wavefield radiated from a vibrating building into its surroundings, and the estimation of the amount of energy associated with it. The approach consists of four steps: estimation of the resonant frequencies of the building, deconvolution of the earthquake recordings from a building and its surroundings, identification of the seismic phases, reconstruction of the signal transmitted from the building to its surroundings, and estimation of its energy, and polarization analysis. Analysis of recordings of the M4.6 event highlighted that the motion related to the wavefield radiated from the building to the ground was mostly linearly polarized in the radial and transverse planes, while a clear ellipticity was observed only in the horizontal plane. The wavefield radiated from the building might be dominated by unconventionally polarized surface waves, i.e., quasi-Rayleigh waves or a combination of quasi-Rayleigh and quasi-Love waves. The results indicated that the energy transmitted from the analyzed vibrating building to its surroundings was significant and decreased the ground motion shaking due to the out-of-phase motion.
KW - Radiated wavefield
KW - Earthquake data
KW - Seismic signal reconstruction
KW - Particle motion trajectory
KW - Wave propagation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582931
DO - https://doi.org/10.1007/s10518-023-01750-7
SN - 1570-761X
SP - 1
EP - 25
PB - Springer Science and Business Media LLC
AN - OPUS4-58293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wätzold, Florian
A1 - Popiela, Bartosz
A1 - Mayer, Jonas
T1 - Methodology for AI-Based Search Strategy of Scientific Papers: Exemplary Search for Hybrid and Battery Electric Vehicles in the Semantic Scholar Database
N2 - The rapid development of artificial intelligence (AI) has significantly enhanced productivity, particularly in repetitive tasks. In the scientific domain, literature review stands out as a key area where AI-based tools can be effectively applied. This study presents a methodology for developing a search strategy for systematic reviews using AI tools. The Semantic Scholar database served as the foundation for the search process. The methodology was tested by searching for scientific papers related to batteries and hydrogen vehicles with the aim of enabling an evaluation for their potential applications. An extensive list of vehicles and their operational environments based on international standards and literature reviews was defined and used as the main input for the exemplary search. The AI-supported search yielded approximately 60,000 results, which were subjected to an initial relevance assessment. For the relevant papers, a neighbourhood analysis based on citation and reference networks was conducted. The final selection of papers, covering the period from 2013 to 2023, included 713 papers assessed after the initial review. An extensive discussion of the results is provided, including their categorisation based on search terms, publication years, and cluster analysis of powertrains, as well as operational environments of the vehicles involved. This case study illustrates the effectiveness of the proposed methodology and serves as a starting point for future research. The results demonstrate the potential of AI-based tools to enhance productivity when searching for scientific papers.
KW - Search strategy
KW - Methodology
KW - Artificial intelligence
KW - Literature review
KW - Battery electric vehicles
KW - Hydrogen-powered vehicles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622012
DO - https://doi.org/10.3390/publications12040049
VL - 12
IS - 4
SP - 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-62201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ghaznavi, Ali
A1 - Kästle, Emanuel D.
A1 - Popiela, Bartosz
A1 - Duffner, Eric
T1 - Damage monitoring of hydrogen composite pressure vessels using acoustic emission technique and machine learning
N2 - A good understanding of the structural stability of hydrogen composite overwrapped pressure vessels (COPV) is important for the cost-effective design and safe operation of hydrogen storage systems. Acoustic emission (AE) monitoring is a non-destructive method sensitive to microstructural damages such as e.g. fiber breakage, and matrix cracking in COPVs. This study proposes a novel approach for damage monitoring by integrating acoustic emission techniques with machine learning (ML) algorithms to classify and predict damage types in COPVs. However, training accurate classification models requires extensive labeled datasets, which are very challenging to generate due to the nature of AE signal data and the lack of in-situ observations of microscopic failures in COPVs. Our research overcomes this limitation by automating the labeling process of AE signal data for different COPVs using unsupervised ML methods. The most representative features were extracted and then selected from recorded AE signals. Different unsupervised clustering algorithms were utilized based on various extracted feature combinations. The most stable clustering result was achieved and later used as appropriate labels for training classification algorithms. A deep neural network-based deep learning (DL) architecture was used to train discriminative models on AE data, identify patterns, and classify damage types into different classes with improved accuracy and speed for each COPV. Results demonstrate the potential of the proposed combined deep learning approach to train predictive models in identifying failure patterns. The trained models based on individual COPVs show high training, validation, and test accuracy for unseen datasets and offer enhanced predictive capabilities by following advanced DL techniques compared to traditional monitoring methods. The proposed method highlights its potential to improve the efficiency and safety of hydrogen storage systems.
T2 - SCHALL 25
CY - Dresden, Germany
DA - 26.03.2025
KW - Sequential Neural Network
KW - Acoustic Emission
KW - Composite Overwrapped Pressure Vessels
KW - Damagemonitoring
KW - Machine Learning
KW - Deep Learning
KW - Deep Neural Network
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629040
DO - https://doi.org/10.58286/30958
SP - 1
EP - 12
AN - OPUS4-62904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghafafian, Carineh
A1 - Popiela, Bartosz
A1 - Trappe, Volker
T1 - Failure Mechanisms of GFRP Scarf Joints under Tensile Load
N2 - A potential repair alternative to restoring the mechanical properties of lightweight fiberreinforced polymer (FRP) structures is to locally patch these areas with scarf joints. The effects of such repair methods on the structural integrity, however, are still largely unknown. In this paper, the mechanical property restoration, failure mechanism, and influence of fiber orientation mismatch between parent and repair materials of 1:50 scarf joints are studied on monolithic glass fiber-reinforced polymer (GFRP) specimens under tensile load. Two different parent orientations of [-45/+45]2S and [0/90]2S are exemplarily examined, and control specimens are taken as a baseline for the tensile strength and stiffness property recovery assessment. Using a layer-wise stress analysis with finite element simulations conducted with ANSYS Composite PrepPost to support the experimental
investigation, the fiber orientation with respect to load direction is shown to affect the critical regions and thereby failure mechanism of the scarf joint specimens.
KW - Scarf joint
KW - Glass fiber reinforced polymers
KW - Failure mechanisms
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523952
DO - https://doi.org/10.3390/ma14071806
VL - 14
IS - 7
SP - 1806
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Reduction in Train-Induced Vibrations—Calculations of Different Railway Lines and Mitigation Measures in the Transmission Path
N2 - The reduction in train-induced ground vibrations by different railway lines and by mitigation measures in the propagation path was analysed in a unified approach by two-dimensional finite element calculations. In general, there was no reduction at low frequencies, and the reduction be-came stronger with increasing frequencies. A maximum reduction of 0.1 at high frequencies was established with an open trench. Reductions between 0.7 and 0.2 have been found for the other sit-uations, filled trenches, walls, plates, and blocks, as well as for railway lines on dams, in cuts and in a tunnel. Bridges can produce amplifications due to their resonance frequencies, but also strong reductions due to massive bridge piers. The influence of some parameters has been analysed, such as the bridge span, the inclination of the dam and the cut, the stiffness of the soil, and the tunnel structure. The dynamic track stiffnesses of a surface, bridge, and tunnel track have been calculated using the 3D finite-element boundary-element method for comparison with corresponding meas-urements.
KW - Train-induced vibration
KW - Mitigation
KW - Trench
KW - Obstacles
KW - Tunnel
KW - Bridge
KW - Finite element
KW - Boundary element
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579573
DO - https://doi.org/10.3390/app13116706
VL - 13
IS - 11
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-57957
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Site-specific amplitude-distance laws, wave velocities, damping, and transfer functions of the soil from hammer impacts and application to railway-induced ground vibration – Similarities and mid-frequency differences
N2 - The propagation of ground vibrations is theoretically analysed with frequency-wavenumber and simplified methods. Experimental methods are presented which can characterise the site-specific ground vibrations by wave velocities, stiffness and damping. Measurements with hammer and train excitation have been performed at several sites. The one-third octave spectra show the stiffness-dependent amplitudes and the low- and high-frequency filter effects due to the layering and the damping of the soil. Specific train effects, an additional high-frequency filter, the sleeper passage frequency, and an amplified mid-frequency component can be clearly found. The attenuation with distance is analysed in detail where the theoretical exponential and the empirical frequency-dependent power law are considered. Hammer and train excitation show the same site-specific effects which are mainly due to the stronger or weaker damping of the soil. The train attenuation is generally weaker than the hammer attenuation. The attenuation exponent of the power law, which is strongly dependent on the site and the frequency, is reduced for the train vibration by 0.3 to 0.5 in agreement with the theory. Reasons are discussed for the overall power law and for the dominating mid-frequency component.
KW - Hammer impact
KW - Train passage
KW - Layered soil
KW - Attenuation
KW - Filter effects
KW - Randomly heterogeneous soil
KW - Scattering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585020
DO - https://doi.org/10.1007/s42417-023-01095-0
SN - 2366-2557
SP - 1
EP - 17
PB - Springer
AN - OPUS4-58502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
A1 - Song, Jiaojiao
T1 - Dynamic damage detection of slab tracks – finite element models on Winkler soil and finite-element boundary-element models on continuous soil
N2 - The train passages over intact or damaged slab tracks on different soils have been calculated by two methods. The finite element method (FEM) uses a Winkler soil under the track model by adding a thin “soil layer”. The combined finite element boundary element method has a continuous soil model which is included by the boundary element method. The basic results are the distributions of the track (rail, track plate, and base layer) displacements along the track for a single axle laod. These solutions are superposed to a complete train load and transformed to time histories. The influence of track and soil parameters has been analysed. The main interest is the influence of the track damage. A gap between track plate and base layer of different lengths has been studied for changes in amplitudes and widths of deflection. A best fit to measured track displacements has been found so that the track damage can be identified and quantified. The FEM model with Winkler soil cannot be fitted to the amplitude and width with the same soil parameters. Therefore, the FEBEM model is preferable for these railway track problems.
KW - Track damage quantification
KW - Finite element method
KW - Combined finite-element boundary-element method
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562207
DO - https://doi.org/10.3390/civileng3040055
SN - 2673-4109
VL - 3
IS - 4
SP - 979
EP - 997
PB - MDPI
CY - Basel
AN - OPUS4-56220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Athman, Rukeia
A1 - Rädler, Jörg
A1 - Löhmann, Oliver
A1 - Ariza de Schellenberger, Angela
A1 - Muth, Thilo
T1 - The BAM Data Store
N2 - As a partner in several NFDI consortia, the Bundesanstalt für Materialforschung und -prüfung (BAM, German federal institute for materials science and testing) contributes to research data standardization efforts in various domains of materials science and engineering (MSE). To implement a central research data management (RDM) infrastructure that meets the requirements of MSE groups at BAM, we initiated the Data Store pilot project in 2021. The resulting infrastructure should enable researchers to digitally document research processes and store related data in a standardized and interoperable manner. As a software solution, we chose openBIS, an open-source framework that is increasingly being used for RDM in MSE communities.
The pilot project was conducted for one year with five research groups across different organizational units and MSE disciplines. The main results are presented for the use case “nanoPlattform”. The group registered experimental steps and linked associated instruments and chemicals in the Data Store to ensure full traceability of data related to the synthesis of ~400 nanomaterials. The system also supported researchers in implementing RDM practices in their workflows, e.g., by automating data import and documentation and by integrating infrastructure for data analysis.
Based on the promising results of the pilot phase, we will roll out the Data Store as the central RDM infrastructure of BAM starting in 2023. We further aim to develop openBIS plugins, metadata standards, and RDM workflows to contribute to the openBIS community and to foster RDM in MSE.
T2 - 1st Conference on Research Data Infrastructure
DA - 12.09.2023
KW - Research Data Infrastructure
KW - Electronic Lab Notebook (ELN)
KW - openBIS
KW - Research Data Management
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596032
DO - https://doi.org/10.52825/CoRDI.v1i.229
VL - 1
SP - 1
EP - 5
AN - OPUS4-59603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosenbusch, Ivo
A1 - Arai, Marylyn Setsuko
A1 - Rizzo, Fabio
A1 - de Camargo, Andrea S. S.
A1 - Ravoo, Bart Jan
T1 - A host–guest approach to ratiometric pH sensing using upconversion nanoparticles
N2 - A new pH nanosensor based on β-NaYF4:Yb3+/Tm3+ upconversion nanoparticles functionalized with cyclodextrin and a pH-sensitive adamantane-modified nitrobenzoxadiazole dye (NBD-Ad).
KW - Host-guest materials
KW - Upconversion nanoparticles
KW - Ratiometric optical sensors
KW - pH sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637722
DO - https://doi.org/10.1039/d5na00145e
SN - 2516-0230
VL - 7
IS - 13
SP - 4142
EP - 4151
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bourgon, Nicolas
A1 - Oelze, Marcus
A1 - Roberts, Patrick
T1 - Less is more: Limiting semi-invasive sampling for multi-isotope analyses and increasing data output from single aliquot samples
N2 - Developments in multi-isotope applications now enable the production of direct and precise life history data of studied archeological and paleoanthropological specimens, with analysis of tooth enamel proving particularly powerful in deep-time preservation contexts. However, the increasing amount of sample material necessary too-often compromises the specimen's structural integrity. Finding ways of minimizing semi-invasive sampling while maximizing produced data thus becomes increasingly crucial. In this study, we examine ways of optimizing sample use for state-of-the-art isotope measurements of enamel-bound zinc (δ66Zn), an increasingly used method in multi-isotope archeological research. We show that certain desolvating nebulizer introduction systems can be used to measure δ66Zn with high efficiency and accuracy using less than half the usual sample size. Moreover, we demonstrate that remaining samples subjected to typical pretreatments used for tooth enamel carbonate (δ13C and δ18O) studies can be safely used without alterations to δ66Zn values. Similarly, we highlight that the often-discarded matrix fraction from zinc chromatography can be utilized for further analyses, such as measurements of 87Sr/86Sr ratios. Our results underscore the possibility of extracting the maximum information from specimens while altogether avoiding or significantly reducing semi-invasive sampling.
KW - Multi-isotope
KW - Zinc isotope analysis
KW - Tooth enamel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637986
DO - https://doi.org/10.1016/j.jas.2025.106308
SN - 0305-4403
VL - 180
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-63798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Popiela, Bartosz
A1 - Günzel, Stephan
A1 - Schukar, Marcus
A1 - Mair, Georg W.
A1 - Krebber, Katerina
A1 - Seidlitz, Holger
T1 - Impact of internal pressure control during manufacturing on residual stresses and safety performance of type 4 pressure vessels
N2 - Composite pressure vessels are commonly manufactured using the wet filament winding process, where various process parameters can influence the performance of the finished component. In this study two designs of wet filament wound 6.8-liter type 4 composite pressure vessels were manufactured. Both differ only by the internal pressure used during the filament winding, which primarily influences the residual stress state in the composite structure. An extensive experimental study was carried out, including 10 slow burst tests and strain measurements with fiber optic sensors. Significant differences can be observed in the performance of the two designs even though the used stacking sequence, materials and other manufacturing parameters are the same for both designs. A discussion of the differences in the behavior of both cylinder types is provided, including the strain distribution in slow burst tests and failure mechanism.
KW - Residual stresses
KW - Slow burst tests
KW - Filament winding
KW - Type 4 composite pressure vessels
KW - Hydrogen
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626663
DO - https://doi.org/10.1016/j.jcomc.2025.100581
SN - 2666-6820
VL - 17
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-62666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xie, Zhuocheng
A1 - Atila, Achraf
A1 - Guénolé, Julien
A1 - Korte-Kerzel, Sandra
A1 - Al-Samman, Talal
A1 - Kerzel, Ulrich
T1 - Predicting grain boundary segregation in magnesium alloys: An atomistically informed machine learning approach
N2 - Grain boundary (GB) segregation substantially influences the mechanical properties and performance of magnesium (Mg). Atomic-scale modeling, typically using ab-initio or semi-empirical approaches, has mainly focused on GB segregation at highly symmetric GBs in Mg alloys, often failing to capture the diversity of local atomic environments and segregation energies, resulting in inaccurate structure-property predictions. This study employs atomistic simulations and machine learning models to systematically investigate the segregation behavior of common solute elements in polycrystalline Mg at both 0 K and finite temperatures. The machine learning models accurately predict segregation thermodynamics by incorporating energetic and structural descriptors. We found that segregation energy and vibrational free energy follow skew-normal distributions, with hydrostatic stress, an indicator of excess free volume, emerging as an important factor influencing segregation tendency. The local atomic environment’s flexibility, quantified by flexibility volume, is also crucial in predicting GB segregation. Comparing the grain boundary solute concentrations calculated via the Langmuir-McLean isotherm with experimental data, we identified a pronounced segregation tendency for Nd, highlighting its potential for GB engineering in Mg alloys. This work demonstrates the powerful synergy of atomistic simulations and machine learning, paving the way for designing advanced lightweight Mg alloys with tailored properties.
KW - Machine learning
KW - Grain boundary segregation
KW - Magnesium alloys
KW - Atomistic simulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638499
DO - https://doi.org/10.1016/j.jma.2025.03.021
SN - 2213-9567
VL - 13
IS - 6
SP - 2636
EP - 2650
PB - Elsevier B.V.
AN - OPUS4-63849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seifert, Lando
A1 - Müller, Thoralf
A1 - Bettge, Dirk
A1 - Moersch, Jörg
A1 - Isecke, Bernd
A1 - Ebell, Gino
T1 - Stress Corrosion Tests for Prestressing Steels—Part 2: Susceptibility of Quenched and Tempered Wires—Influence of Chromium
N2 - Due to the risk of failure in existing prestressed concrete bridges, the assessment of the susceptibility of prestressing steel to hydrogen‐induced stress corrosion cracking will become more important in the future. At present, the used normative ISO 15630‐3 test gives unpersuasive and diverging results using a free corrosion approach for the needed hydrogen charging for stress corrosion cracking initiation. A newly developed test method uses the cathodic polarization to control the supply of electrons for hydrogen charging instead of an uncontrolled and variable supply of electrons by metal dissolution during free corrosion. Experimental data shows a reliable differentiation between highly susceptible known quenched and tempered wires and robust cold‐drawn wires with this new test. A round robin with eight participating testing institutes demonstrated the reproducibility of results testing a cold‐drawn wire batch of St 1470/1670. In contrast to previously reported experience in the literature, the new method ranks the Cr‐alloyed quenched and tempered (“new‐type”) wires as highly‐susceptible as the “old‐type” wires without Cr‐alloy.
KW - Cathodic polarization
KW - Chemical composition
KW - Chromium
KW - Prestressing steels
KW - Quenched and tempered
KW - Stress corrosion cracking
KW - Susceptibility
KW - Wires
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639735
DO - https://doi.org/10.1002/maco.70033
SN - 0947-5117
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-63973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janczynski, Jessica
A1 - Tewes, Andreas
A1 - Ulbricht, Alexander
A1 - Jaenisch, Gerd-Rüdiger
T1 - Evaluation Metrics for Comparison between Virtual and Industrial XCT
N2 - Simulations of XCT systems, as employed in the context of the manufacturing and design process, represent a time-saving, cost- and resource-efficient alternative to repeated experimental measurements. This article is dedicated to the development and evaluation of various metrics that should enable an adequate verification and optimization of a XCT simulation of an experimental XCT system. The present study employed statistical evaluation as a methodological approach. The present article makes a significant contribution to the optimization of the development process of a XCT simulation and provides a foundation for future research activities in this field.
KW - Computed Tomography
KW - Computertomographie
KW - aRTist
KW - Simulation
KW - Virtual CT
KW - Evaluation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641444
DO - https://doi.org/10.1007/s10921-025-01213-w
SN - 0195-9298
VL - 44
IS - 4
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
CY - Berlin/Heidelberg
AN - OPUS4-64144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grohmann, Maria
A1 - Maack, Stefan
A1 - Behrens, Matthias
A1 - Niederleithinger, Ernst
T1 - Low-frequency ultrasonic pulse-echo datasets for geometry determination of a reinforced concrete step specimen with embedded polystyrene foam cuboids in non-destructive testing
N2 - The dataset comprises raw data collected using the ultrasonic pulse-echo method on a concrete specimen. The specimen addresses two fundamental non-destructive testing (NDT) challenges in civil engineering: locating built-in elements and determining dimensions to analyse both the internal and external geometry of concrete structures.
For data acquisition, the surface of the concrete specimen was automatically scanned point by point, with pulse-echo measurements performed at each measuring point. The automation of the measurement process ensured high repeatability and precision as well as a high measurement point density. Two low-frequency probes were used, each capable of both transmitting and receiving ultrasonic waves: one for longitudinal waves and one for shear waves. The longitudinal wave probe operates at frequencies of up to approximately 160 kHz, whereby a frequency of 80 kHz was used for the ultrasonic measurements here. The shear wave probe operates at up to 100 kHz, with a frequency of 50 kHz used for the measurements in this study. This article includes additional technical specifications of the two ultrasonic probes used, as well as information on their geometric specifications and directivity patterns. It also provides a detailed description of the further measurement equipment used. The ultrasonic raw data are stored in a universally readable format, with each time signal (A-scan) spanning two milliseconds and a sampling rate of two mega-samples per second. The provided data support comparative studies in signal analysis, imaging as well as interpretation and can be used for evaluation purposes in various practical NDT scenarios.
KW - Civil engineering
KW - Concrete structures
KW - Ultrasonic echo testing
KW - Reference data
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639100
DO - https://doi.org/10.1016/j.dib.2025.111956
SN - 2352-3409
VL - 62
SP - 1
EP - 19
PB - Elsevier Inc.
AN - OPUS4-63910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liao, Chun-Man
A1 - Niederleithinger, Ernst
A1 - Bernauer, F
A1 - Igel, H
A1 - Hadziioannou, Céline
T1 - Wave-Screening Methods for Prestress-Loss Assessment of a Large-Scale Post-Tensioned Concrete Bridge Model Under Outdoor Conditions
N2 - This paper presents advancements in structural health monitoring (SHM) techniques, with a particular focus on wave-screening methods for assessing prestress loss in a large-scale prestressed concrete (PC) bridge model under outdoor conditions. The wave-screening process utilizes low-frequency wave propagation obtained from seismic interferometry of structural free vibrations and high-frequency wave propagation obtained through ultrasonic transducers embedded in the structure. An adjustable post-tensioning system was employed in a series of experiments to simulate prestress loss. By comparing bridge vibrations under varying post-tensioning forces, the study investigated prestress loss and examined temperature-related effects using the coda wave interferometry (CWI) method. Local structural alterations were analyzed through wave velocity variations, demonstrating sensitivity to bridge temperature changes. The findings indicate that wave-based methods are more effective than traditional modal analysis for damage detection, highlighting the dual impacts of prestress loss and temperature, as well as damage localization. This study underscores the need for long-term measurements to account for temperature fluctuations when analyzing vibration measurements to investigate changes in prestressing force in PC structures.
KW - Coda wave interferometry
KW - Damage detection
KW - Prestress loss
KW - Seismic interferometry
KW - SHM
KW - Temperature influence
KW - Ultrasonics
KW - Wave-screening
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634244
UR - https://www.mdpi.com/2076-3417/15/11/6005
DO - https://doi.org/10.3390/app15116005
VL - 15
IS - 11
SP - 1
EP - 18
PB - MDPI
AN - OPUS4-63424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharek, Vera M.
A1 - Pfeifer, Jens
A1 - Vogl, Jochen
A1 - Traub, Heike
A1 - Meermann, Björn
T1 - Tin fractionation analysis in sediment samples via on-line ID ETV/ICP-MS
N2 - We report a quantification approach for directly determining total tin and tin-based pollutants/species in sediments via electrothermal vaporization/inductively coupled plasma-mass spectrometry (ETV/ICP-MS) utilizing an on-line isotope dilution mass spectrometry (IDMS) approach. The method was developed and validated using an estuarine sediment reference material (BCR-277R), yielding a recovery of 106%. A relative standard deviation (RSD) of 14%, comparable to published data using a similar method, was obtained. A limit of quantification (LOQ) was estimated at 0.008 mg Sn kg−1 and sufficient for quantifying the total tin mass fraction of surface sediments along the tidal River Elbe course. Hereby, a decrease towards the river mouth, presumably due to dilution effects by less polluted marine sediment, was observed. Besides total tin, monitoring of organotin compounds (OTCs)/species is of interest in sediments due to their toxic effects on aquatic life. The method’s capability was extended by separating an OTC fraction in a sediment certified reference material (CRM) through the ETV temperature program. While spiking experiments with OTC standards confirmed the assignment, only a small fraction of the total certified OTC amount (3%), likely due to matrix effects, was recovered. However, applying the method to real-world samples, OTCs were detectable along the River Elbe course. By this, we demonstrated the potential of our method as a complementary fast-screening approach to species-specific analysis procedures.
KW - ETV
KW - Sn-Speciation
KW - Sediment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640137
DO - https://doi.org/10.1007/s00216-025-06064-y
SN - 1618-2642
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-64013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epple, Niklas
A1 - Sanchez Trujillo, Camila
A1 - Fontoura Barroso, Daniel
A1 - Hau, Julia
A1 - Niederleithinger, Ernst
ED - Lienhart, Werner
ED - Krüger, Markus
T1 - Monitoring of Concrete Infrastructure with Active Ultrasound Coda Wave Interferometry
N2 - Coda Wave Interferometry has been used in Geophysics to detect weak changes in scattering media. Past research in Structural Health Monitoring has shown that this methodology can be applied to concrete structures to detect material changes by calculation of relative velocity changes. Successive measurements with embedded ultrasonic transducers provide a repeatable signal for reliable long-term monitoring of concrete. To research the application in real-world structures, we have embedded ultrasonic transducers in a bridge in Ulm and a Metro station in Munich, Germany. This study gives an overview of the monitoring of these two structures. The results show the potential and challenges of the method. Data evaluation can be largely automated to gain insights into material changes and other influences on the structure, such as traffic-induced load and temperature variations. The experiments demonstrate the ease of installation, longevity of the sensor installation, and sensitivity of the measurement technique, but highlight problems with the application, especially if electromagnetic noise affects data quality. As no confirmed substantial damage was recorded during the monitoring period on both structures, we evaluate load tests to investigate the effect of static load on the structures and the coda monitoring results. The experiments show that the influence of load can be detected, even if the temperature influence is not removed from the data. This indicates that online damage detection with coda monitoring is possible, but further research on damage detection in real-world structures has to be conducted to confirm laboratory findings.
T2 - 13th International Conference on Structural Health Monitoring of Intelligent Infrastructure
CY - Graz, Austria
DA - 01.09.2025
KW - Active Ultrasound Measurements
KW - Coda Wave Monitoring
KW - Embedded Transducers
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640582
DO - https://doi.org/10.3217/978-3-99161-057-1-012
SP - 45
EP - 51
PB - Technische Universität Graz
CY - Graz
AN - OPUS4-64058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feord, Helen K.
A1 - Trautwein-Schult, Anke
A1 - Keuschnig, Christoph
A1 - Ostrzinski, Anne
A1 - Peter, Elisa K.
A1 - Jaeger, Carsten
A1 - Lisec, Jan
A1 - Mourot, Rey
A1 - Peters, Ravi Sven
A1 - Çiftçi, Ozan
A1 - Tranter, Martyn
A1 - Anesio, Alexandre M.
A1 - Becher, Dörte
A1 - Benning, Liane G.
T1 - Algae-dominated metaproteomes uncover cellular adaptations to life on the Greenland Ice Sheet
N2 - Eukaryotic algae-dominated microbiomes thrive on the Greenland Ice Sheet (GrIS) in harsh environmental conditions, including low temperatures, high light, and low nutrient availability. Chlorophyte algae bloom on snow, while streptophyte algae dominate bare ice surfaces. Empirical data about the cellular mechanisms responsible for their survival in these extreme conditions are scarce. This knowledge gap was addressed by quantifying proteins for both algal taxa from samples on the southern margin of the GrIS. We show that the streptophyte glacier ice algae have a relative enrichment in proteins involved in environmental signaling and nutrient transport, indicative of cellular readiness to dynamically respond to extreme GriS environmental cues, linked, for example, to photoprotection and the rapid update of scarce nutrients. In contrast, the chlorophyte snow algae have a high abundance of proteins linked to lipid and nitrogen metabolisms, providing evidence for the biological processes sustaining the cellular carbon and nitrogen stores necessary for survival in an oligotrophic environment. We also identify proteins in both taxa linked to the synthesis and breakdown of key cellular pigments. Our study gives novel insights into the cellular biology of these algae and their adaptation to extreme environments.
KW - Metabolic profiling
KW - Mass spectrometry
KW - Ice algae
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641037
DO - https://doi.org/10.1038/s41522-025-00770-2
SN - 2055-5008
VL - 11
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-64103
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Mathies, Helena
A1 - Lisec, Jan
T1 - Leaching and transformation of film preservatives in paints induced by combined exposure to ultraviolet radiation and water contact under controlled laboratory conditions
N2 - Stormwater from urban areas can transport biocidally active substances and related transformation products from buildings into the environment. The occurrence of these substances in urban runoff depends on the availability of water, and on ultraviolet radiation exposure that causes photolytic reactions. In a systematic laboratory study, painted test specimens were exposed to either ultraviolet radiation, water contact, or a combination of both. Leaching of the biocidally active substances carbendazim, diuron, octylisothiazolinone, terbutryn, and selected transformation products of terbutryn and diuron were observed under various exposure conditions. Remaining concentrations of these substances in the paint were quantified. It was demonstrated that the distribution of active substances and transformation products in eluates and in the coatings themselves differs with exposure conditions. Strategies for environmental monitoring of biocide emissions need to consider the most relevant transformation products. However, environmental concentrations of biocidally active substances and transformation products depend on earlier exposure conditions. As a consequence, monitoring data cannot describe emission processes and predict expected leaching of biocidally active substances from buildings if the data are collected only occasionally.
KW - Substance release
KW - Construction products
KW - Biocides
KW - Transformation
KW - UV radiation
KW - Water contact
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532114
DO - https://doi.org/10.3390/w13172390
SN - 2073-4441
VL - 13
IS - 17
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53211
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schannor, Mathias
A1 - Oelze, Marcus
A1 - Traub, Heike
A1 - He, Yubei
A1 - Schmidt, Robin
A1 - Heidemann, Luisa
A1 - Savic, Lynn Jeanette
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Advancing Biomarker Research: In Situ Cu Isotope Analysis in Liver Tumors by LA-MC-ICP-MS
N2 - Stable metal isotopes have received increasing attention as medical biomarkers due to their potential to detect changes in metal metabolism related to diseases. In particular, copper stable isotopes are a powerful tool to identify isotopic variation between tumors and healthy tissue, suggesting application in cancer diagnosis. However, potential mechanisms causing isotope fractionation, such as redox- or bond-forming reactions and interactions of metals during transmembrane import and export, are less well understood. Here, we established an in situ method using laser ablation-multicollector-inductively coupled plasma-mass spectrometry (LA-MC-ICP-MS) to advance our understanding of the underlying processes responsible for isotope fractionation between normal and diseased tissues. Gelatin-based bracketing standards and quality control reference materials, crucial for laser ablation analysis, were developed to allow correction for instrumentally induced isotope fractionation during LA-MC-ICP-MS analysis. Using such matrix-matched standards, the method achieved intermediate precisions for delta values of better than 0.15 ‰ (2 s) for inorganic reference materials and of better than 0.17 ‰ (2 s) for biological reference materials. The developed routine was tested on rabbit VX2 liver tumor samples, a model system resembling human hepatocellular carcinoma (HCC) used to study liver cancer. In situ Cu isotope compositions between healthy (𝛿65/63NIST976(Cu) = −1.5 ‰ to 0.2 ‰) and tumorous (𝛿65/63NIST976(Cu) = 0.0 ‰ to 1.3 ‰) liver tissue show distinct differences in their isotope ratios. The observed isotopic dichotomy is consistent with previous solution-based MC-ICP-MS work, showing enrichment of heavy 65Cu in cancer biopsies relative to healthy tissue.
KW - Biomarker
KW - Laser Ablation
KW - Reference Material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626865
DO - https://doi.org/10.1021/acs.analchem.4c05626
SN - 1520-6882
VL - 97
IS - 8
SP - 4425
EP - 4432
PB - American Chemical Society (ACS)
AN - OPUS4-62686
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epple, Niklas
A1 - Schumacher, Thomas
A1 - Murtuz, A. K. M. Golam
A1 - Niederleithinger, Ernst
A1 - Dusicka, Peter
T1 - Combined passive and active ultrasonic stress wave monitoring of a full‑scale laboratory reinforced concrete bridge column subject to reverse‑cyclic lateral loading
N2 - Effective monitoring of reinforced concrete structures requires techniques that detect early-stage material change and active, localized cracking. This study investigates a combined structural health monitoring approach using passive acoustic emission and active ultrasonic methods on a full-scale reinforced concrete bridge column subjected to reverse-cyclic lateral loading.
Active monitoring, based on coda wave interferometry, was used to track changes in wave velocity and waveforms, while passive acoustic emission monitoring was used to detect crack activity. The instrumentation consisted of three embedded ultrasonic transducers and three surface-mounted acoustic emission sensors. The results show that active ultrasonic monitoring is most effective prior to visual damage, successfully detecting the onset of internal cracking via wave velocity decreases exceeding 0.4%, and distinguishing load-induced effects from permanent damage. However, its utility diminished in later stages of damage progression, as strong signal decorrelation hindered further data interpretation. Additionally, active US measurements allowed a comparison of damage severity in different parts of the column. Conversely, passive acoustic emission monitoring effectively tracked the formation of concrete cracks throughout the experiment, with distinct event clusters and high-amplitude signals (> 60 dB) confirming ongoing fracture processes in all damage states. This study confirms that combining these methods results in a more robust structural health monitoring strategy by leveraging their complementary strengths. Active techniques excel at tracking continuous material changes in early damage states, while passive methods are superior for detecting discrete cracking events as damage progresses. Importantly, both methods can utilize the same measurement equipment, enabling a cost-effective approach to continuous damage tracking.
KW - Coda wave interferometry
KW - Active ultrasonic monitoring
KW - Acoustic emission
KW - Structural health monitoring
KW - Nondestructive evaluation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638689
DO - https://doi.org/10.1007/s13349-025-00996-w
SN - 2190-5479
SP - 1
EP - 24
PB - Springer Nature
AN - OPUS4-63868
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Löwa, N.
A1 - Golusda, L.
A1 - Paclik, D.
A1 - Traub, Heike
A1 - Schannor, Mathias
A1 - Saatz, Jessica
A1 - Freise, C.
A1 - Taupitz, M.
A1 - Siegmund, B.
A1 - Kühl, A. A.
A1 - Wiekhorst, F.
T1 - Magnetic particle spectroscopy for Eu-VSOP quantification in intestinal inflammation: Distinguishing nanoparticle signals from dietary contamination
N2 - Magnetic nanoparticles are gaining increasing attention as a promising alternative to gadolinium-based contrast agents in magnetic resonance imaging, primarily due to their low toxicity. In this study, we investigated the use of magnetic iron oxide nanoparticles in mouse models of intestinal inflammation to assess their potential for detecting changes in the extracellular matrix. For magnetic quantification, we employed magnetic particle spectroscopy, which offers high sensitivity and minimal interference from biological tissue. However, we observed significant variations in magnetic signals within the intestine, as well as measurable signals in control animals, indicating possible magnetic contamination. By doping the nanoparticles with europium, we were able to confirm this suspicion through quantitative elemental analysis. Examination of mouse feed and feces allowed us to identify the source of contamination. Based on these findings, we developed a method to reliably distinguish genuine signals of magnetic nanoparticles from those caused by external magnetic contaminations. This approach is essential to ensure reliable results in future diagnostic and preclinical research.
KW - ICP-MS
KW - Nanoparticle
KW - Magnetic particle spectroscopy
KW - Quantification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642238
DO - https://doi.org/10.1039/D5NA00452G
SN - 2516-0230
IS - 00452
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mege-Revil, Alexandre
A1 - Rapontchombo-Omanda, Jessie
A1 - Serrano-Munoz, Itziar
A1 - Cristol, Anne-Lise
A1 - Magnier, Vincent
A1 - Dufrenoy, Philippe
T1 - Sintered Brake Pads Failure in High-Energy Dissipation Braking Tests: A Post-Mortem Mechanical and Microstructural Analysis
N2 - The industrial sintering process used to produce metallic matrix pads has been altered to diminish the amount of copper used. Unfortunately, replacing a large part of the copper with iron seems to have reached a limit. In the high-energy, emergency-type rail braking used in this study, the materials are put to the very limit of their usage capacity, allowing us to observe the evolution of the microstructure and mechanical properties of sintered, metallic matrix pads. After the braking test, their compressive behaviour was assessed using digital image correlation (DIC), and their microstructure with scanning electron microscopy (SEM). The worn material has three flat layers with different microstructures and compressive behaviours. The boom layer seems unmodified. Macroscopic and microscopic cracks run through the intermediate layer (2–15 mm depth). The top layer has stiffened thanks to resolidification of copper. The temperature reaches 1000 °C during the braking test, which also explains the carbon diffusion into iron that result in the weakening of iron–graphite interfaces in the pad. Finally, submicronic particles are detected at many open interfaces of the worn and compressed pad. Associated with the predominant role of graphite particles, this explains the weak compressive behaviour of the pads.
KW - Friction braking
KW - Sintering
KW - Metallic matrix pad
KW - Microstructure
KW - Scanning electron microscopy (SEM)
KW - Compressive test
KW - Cracks
KW - Digital image correlation (DIC)
KW - Diffusion
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587318
DO - https://doi.org/10.3390/ma16217006
SN - 1996-1944
VL - 16
IS - 21
SP - 1
EP - 18
PB - MDPI
AN - OPUS4-58731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Magnier, V.
A1 - Brunel, F.
A1 - Dufrenoy, P.
T1 - Influence of the Composition on the Compressive Behaviour of a Semi-Metallic Brake-Pad Material
N2 - The contact interface between the rotation and static part of a friction brake is central to the optimal functioning of the brake system due to the occurrence of heat dissipation, mechanical interaction and thermal exchanges. Generally, braking performances are evaluated by the energetic efficiency and wear rates of the contact surface. However, the compressive behaviour of the contact materials has also a significant contribution to the overall performances. In this work, the meso- and microscopic compressive behaviour of a sintered semi-metallic brake-pad material is investigated mainly via compression testing coupled with Digital Image Correlation (DIC) technique, as well as optical and scanning electron microscopy (SEM) analysis. The composition of a reference material (RM) is simplified to a selection of nine components, as opposed to up to thirty components typically used in commercial brake-pad materials. The retained components are considered as the most crucial for safe-operating performances. At the studied stress levels, the RM material is flexible (E = 5330 MPa), deformable (Ezz−plastic = −0.21%), and exhibits hysteresis loops. Subsequently, the contribution to the mechanical response of each individual component is investigated by producing the so-called dissociated materials, where the number of components is, at a time, further reduced. It is observed that the macroscopic behaviour is mainly controlled by the content (i.e., size distribution, shape and nature) of graphite particles, and that the hysteresis is only related to one of the two types of graphite used (G2 particles). Moreover, RM containing 13 wt% of G2 particles embedded in a relatively soft matrix (10.86 GPa) is able to increase the hysteresis (by 35%) when compared to the dissociated material containing 20 wt% of G2 particles which is embedded in a stiffer matrix (E = 106 GPa).
KW - Semi-metallic brake-pad material
KW - Powder metallurgy
KW - Components influence
KW - Graphite induced hysteresis
KW - Digital image correlation (DIC)
KW - Compression testing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562003
DO - https://doi.org/10.3390/ma15227911
VL - 15
IS - 22
SP - 7911
PB - MDPI
AN - OPUS4-56200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Walter, Keven
A1 - Hoch, Dominik P.
A1 - Hertweck, Leon
A1 - Balasubramanian, Kannan
A1 - Geisler, Jonas
A1 - Röllig, Mathias
A1 - Neubert, Tilmann J.
A1 - Börner, Hans G.
T1 - Unlocking the Essence of Lignin: High‐Performance Adhesives That Bond via Thiol‐Catechol Connectivities and Debond on Electrochemical Command
N2 - AbstractThe next generation of adhesives requires effective debonding capabilities that can be triggered on demand to enable advanced circular repair and recycling strategies. A new class of lignin‐inspired, two‐component (2K) structural adhesives offers bonding strengths of up to 20 MPa and clean, on‐command electrochemical debonding within 5–30 min. The debonding is induced by a distinct electrochemical oxidation of thiol‐catechol connectivities (TCCs) within the entire adhesive network, enforcing rapid and clean adhesive failure on the cathodic substrate side. The TCC‐functionalities are formed during curing by a thiol‐quinone Michael‐type polyaddition, reacting polyester‐based trithiols with tris‐quinones as lignin‐inspired minimal building blocks. The structural adhesive can be fine‐tuned by adjusting the formulation. The addition of carbon black and ionic liquids facilitates the desired electrochemical transformation of TCC‐catechols to TCC‐quinones. Applying only 9 V for 5–30 min, leads to clean debonding with 72–86% loss of shear strength. A comprehensive study of curing, bonding, and debonding behavior by rheological, spectroscopic, and electrochemical investigations reveals the debonding mechanism by correlating catechol oxidation to adhesive performance. The electrochemical debonding capability of TCC‐structural adhesives is demonstrated in a functional prototype, where on‐command detachment of a cover glass from a display device is achieved within 6.5 min.
KW - Lignin-inspired
KW - Electrochemical-Debonding
KW - Thiol-Catechol-Connectivity (TCC)
KW - Michael-Type Polyaddition
KW - On-Demand Adhesive Failure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639674
DO - https://doi.org/10.1002/adma.202510463
SN - 0935-9648
SP - 1
EP - 10
PB - Wiley VHC-Verlag
CY - 69451 Weinheim
AN - OPUS4-63967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Popiela, Bartosz
A1 - Kim, Kyunghwan
A1 - Lee, Kyu-Jin
A1 - Lee, Jung-Ryul
T1 - Impact of internal pressure regulation in filament winding on the quality of composite cylinders: a study with pulse-echo ultrasonic propagation imaging
N2 - To ensure the safety of composite pressure vessels considering the growing usage, this case study investigates how wet filament winding parameters affect quality of composite cylinders. Two 6.8-liter Type 4 cylinders with identical geometry and fiber stacking sequence were analyzed using pulse-echo ultrasonic propagation imaging. One cylinder was wound under constant internal pressure, while the other used increasing pressure to influence residual stress and influence imperfections. This difference led to distinct failure mechanisms in burst tests. The study focused on identifying porosity and resin-rich areas, visualized through ultrasonic wave propagation imaging and variable time-window amplitude mapping. Results revealed that the cylinder wound with increasing pressure had better composite consolidation but more resin-rich areas in the hoop windings. The findings demonstrate the effectiveness of pulse-echo ultrasonic imaging as a non-destructive method for detecting manufacturing-induced imperfections and highlight the importance of optimizing filament winding parameters to enhance composite quality.
KW - Composite
KW - Pressure vessel
KW - Wet filament winding
KW - Pulse-echo ultrasonic propagation imaging
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639801
DO - https://doi.org/10.1080/09243046.2025.2547457
SN - 1568-5519
SP - 1
EP - 18
PB - Taylor & Francis
AN - OPUS4-63980
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernandez-Menendez, L. J.
A1 - Mendez-Lopez, C.
A1 - Abad Andrade, Carlos Enrique
A1 - Fandino, J.
A1 - Gonzalez-Gago, C.
A1 - Pisonero, J.
A1 - Bordel, N.
T1 - A critical evaluation of the chlorine quantification method based on molecular emission detection in LIBS
N2 - The entire process involving the determination of Cl by molecular emission detection in Laser-Induced Breakdown Spectroscopy (LIBS) is thoroughly studied in this paper. This critical evaluation considers how spectra are normalized, how interferences from other molecular species signals are removed, and how signal integration is applied. Moreover, a data treatment protocol is proposed to achieve reliable and accurate Cl determination from the CaCl molecular spectral signal, not requiring the use of more complex numerical approaches. Calcium chloride dihydrate (CaCl2⋅2H2O) and high purity anhydrite samples (CaSO4) are used to optimize the acquisition conditions and data treatment of CaCl emission signal. Using the developed protocol, calibration curves for Cl, covering the concentration range from 0 μg/g to 60,000 μg/g of Cl, are successfully achieved. Finally, the suitability of the proposed methodology for Cl determination is successfully applied in industrial gypsum waste samples, where the results obtained by LIBS are validated using high-resolution molecular absorption spectroscopy (HR-CS-MAS) and potentiometric titration.
KW - Laser induced breakdown Spectrocopy (LIBS)
KW - Molecular spectra
KW - Chlorine determination
KW - CaCl emission bands
KW - Industrial gypsum
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544292
DO - https://doi.org/10.1016/j.sab.2022.106390
SN - 0584-8547
VL - 190
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-54429
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano-Martín, D.
A1 - Tuma, Dirk
A1 - Kipphardt, Heinrich
A1 - Khanipour, Peyman
A1 - Chamorro, C. R.
T1 - Thermodynamic characterization of the (H2 + C3H8) system significant for the hydrogen economy: Experimental (p, rho, T) determination and equation-of-state modelling
N2 - For the gradual introduction of hydrogen in the energy market, the study of the properties of mixtures of hydrogen with typical components of natural gas (NG) and liquefied petroleum gas (LPG) is of great importance. This work aims to provide accurate experimental (p, rho, T) data for three hydrogen-propane mixtures with nominal compositions (amount of substance, mol/mol) of (0.95 H2 + 0.05 C3H8), (0.90 H2 + 0.10 C3H8), and (0.83 H2 + 0.17 C3H8), at temperatures of 250, 275, 300, 325, 350, and 375 K, and pressures up to 20 MPa. A single-sinker densimeter was used to determine the density of the mixtures. Experimental density data were compared to the densities calculated from two reference equations of state: the GERG-2008 and the AGA8-DC92. Relative deviations from the GERG-2008 EoS are systematically larger than those from the AGA8-DC92. They are within the ±0.5% band for the mixture with 5% of propane, but deviations are higher than 0.5% for the mixtures with 10% and 17% of propane, especially at low temperatures and high pressures. Finally, the sets of new experimental data have been processed by the application of two different statistical equations of state: the virial equation of state, through the second and third virial coefficients, B(T, x) and C(T, x), and the PC-SAFT equation of state.
KW - Hydrogen-containing gas mixture
KW - Density data
KW - Equation of state
KW - Virial coefficients
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570056
DO - https://doi.org/10.1016/j.ijhydene.2022.11.170
SN - 0360-3199
VL - 48
IS - 23
SP - 8645
EP - 8667
PB - Elsevier B. V.
CY - Amsterdam
AN - OPUS4-57005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano-Martín, Daniel
A1 - Kipphardt, Heinrich
A1 - Khanipour, Peyman
A1 - Tuma, Dirk
A1 - Horrillo, Alfonso
A1 - Chamorro, César R.
T1 - Impact of hydrogen addition, up to 20 % (mol/mol), on the thermodynamic (p, ρ, T) properties of a reference high-calorific natural gas mixture with significant ethane and propane content
N2 - Injecting hydrogen into the natural gas grid supports gradual decarbonization. To check the accuracy of equations of state for hydrogen-enriched natural gas mixtures, precise density data from well-characterized reference mixtures are essential. In a prior study, we provided experimental measurements for a natural gas constituted mainly of methane and for two derived hydrogen-enriched mixtures. In the present study, being the second and final part of our investigation, density measurements for a high-calorific natural gas with significant ethane and propane content, along with two hydrogen-enriched variants (10 and 20 mol-% hydrogen) are provided. The mixtures are gravimetrically prepared following ISO 6142-1. Density measurements, conducted with a single-sinker densimeter at temperatures from (260–350) K and pressures up to 20 MPa, are compared with three equations of state: AGA8-DC92, GERG-2008, and an improved GERG-2008. Results indicate that all models perform better for methane-dominant mixtures than for those containing heavier hydrocarbons.
KW - Hydrogen-enriched natural gas
KW - High-pressure density
KW - Reference equation of state
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633371
DO - https://doi.org/10.1016/j.ijhydene.2025.05.173
SN - 0360-3199
VL - 140
SP - 256
EP - 271
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63337
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano-Martín, D.
A1 - Pazoki, F.
A1 - Kipphardt, Heinrich
A1 - Khanipour, P.
A1 - Tuma, Dirk
A1 - Horillo, A.
A1 - Chamorro, C. R.
T1 - Thermodynamic (p, ρ, T) characterization of a reference high-calorific natural gas mixture when hydrogen is added up to 20 % (mol/mol)
N2 - The injection of hydrogen into the natural-gas grid is an alternative during the process of a gradual decarbonization of the heat and power supply. When dealing with hydrogen-enriched natural gas mixtures, the performance of the reference equations of state habitually used for natural gas should be validated by using high-precision experimental thermophysical data from multicomponent reference mixtures prepared with the lowest possible uncertainty in composition. In this work, we present experimental density data for an 11-compound high-calorific (hydrogen-free) natural gas mixture and for two derived hydrogen-enriched natural gas mixtures prepared by adding (10 and 20) mol-% of hydrogen to the original standard natural gas mixture. The three mixtures were prepared gravimetrically according to ISO 6142–1 for maximum precision in their composition and thus qualify for reference materials. A single-sinker densimeter was used to determine the density of the mixtures from (250–350) K and up to 20 MPa. The experimental density results of this work have been compared to the densities calculated by three different reference equations of state for natural gas related mixtures: the AGA8-DC92 EoS, the GERG-2008 EoS, and an improved version of the GERG-2008 EoS. While relative deviations of the experimental density data for the hydrogen-free natural gas mixture are always within the claimed uncertainty of the three considered equations of state, larger deviations can be observed for the hydrogen-enriched natural gas mixtures from any of the three equations of state, especially for the lowest temperature and the highest pressures.
KW - Hydrogen-enriched natural gas
KW - Single-sinker densimeter
KW - High-pressure density
KW - Equations of state
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604742
DO - https://doi.org/10.1016/j.ijhydene.2024.05.028
SN - 0360-3199
VL - 70
SP - 118
EP - 135
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-60474
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhuang, Yiling
A1 - Haderlein, Stefan B.
A1 - Hagemann, Nikolas
A1 - Grafmüller, Jannis
A1 - Gogler, Karolin
A1 - Paul, Andrea
A1 - Fink, Friedrich
A1 - Spahr, Stephanie
T1 - Activation of persulfate by biochar and iron: role of biochar pyrolysis conditions and ash amendments
N2 - Redox-active biochars can enhance contaminant transformation in persulfate-based Fenton-like water treatment by facilitating Fe(III) reduction to Fe(II). However, biochar properties vary greatly depending on both feedstock selection and pyrolysis conditions. Best suited biochars for Fe(III) reduction and persulfate activation have yet to be identified. Here, we investigated eight biochars for their ability to activate persulfate with Fe(III) to transform N,N-diethyl-m-toluamide (DEET) in water. Four of the biochars were produced from beech wood under different pyrolysis conditions (450–750 °C, high and low nitrogen flow rate in the reactor) and four biochars were produced from softwood amended with 0 – 43 weight percent (wt%) wood ash prior to pyrolysis at 500 °C. Beech wood biochar produced at 450 °C transformed DEET most efficiently with a half-life time of 39 ± 4 min, likely due to the high concentration of surface oxygen functional groups and persistent free radicals that accelerated Fe(III) reduction and formation of reactive species. Among the ash-amended biochars, biochar with 16 wt% ash amendment showed the most efficient DEET transformation with a half-life time of 27 ± 0.6 min, which is 10-times faster compared to a non-ash-amended biochar produced from the same biomass under similar pyrolysis conditions. Ash amendment led to the formation of crystalline iron minerals in biochars, which likely promoted Fe(III) reduction and persulfate activation. Our results highlight the potential for fine-tuning the redox properties of biochar, e.g., by ash amendment to a woody feedstock, enabling tailored performance for specific water treatment applications.
KW - Persistent free radicals
KW - Redox-active moieties
KW - Fenton-like systems
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634504
DO - https://doi.org/10.1016/j.seppur.2025.133634
SN - 1383-5866
VL - 374
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sowoidnich, Kay
A1 - Pätzold, Stefan
A1 - Ostermann, Markus
A1 - Sumpf, Bernd
A1 - Maiwald, Martin
T1 - Qualitative and quantitative soil characterization on an agricultural field using a portable shifted excitation Raman difference spectroscopy instrument
N2 - Site-specific farmland management requires comprehensive information about the soil status to derive informed treatment decisions, e.g. for liming or fertilizer recommendations. Standard laboratory methods relying on sample collection have only limited ability to adequately capture the spatial variability of typical agricultural fields. Here, on-site analytical techniques with the potential to measure the soil properties on a substance-specific level and at the required spatial resolution could be very beneficial. Raman spectroscopy is a very promising technique for this purpose as it provides a molecular fingerprint of soil constituents. However, intrinsic soil fluorescence and daylight interference can be major issues masking characteristic Raman signals. Here, we apply an in-house developed portable shifted excitation Raman difference spectroscopy (SERDS) instrument based on a dual-wavelength diode laser emitting around 785 nm to effectively separate the Raman signals of soil from such interferences. SERDS investigations on a selected agricultural field in Germany demonstrate that the Raman spectroscopic signature of 9 soil minerals and organic carbon could successfully be separated from intense backgrounds. Using partial least squares regression against reference analyses, a successful prediction of the soil carbonate (R2 = 0.86, root mean squared error of cross validation RMSECV = 2.49%) and soil organic carbon content (R2 = 0.89, RMSECV = 0.32%) as important soil parameters is realized. The results obtained on-site with the portable instrument were confirmed by SERDS laboratory experiments of collected soil samples thus highlighting the capability and reliability of portable SERDS as promising and complementary tool for precision agriculture
KW - XRF
KW - Raman spectroscopy
KW - Soil
KW - SERDS
KW - Precision agriculture
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634597
DO - https://doi.org/10.1039/d5an00178a
SN - 0003-2654
VL - 150
IS - 13
SP - 2934
EP - 2944
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Golub, Tino Petar
A1 - Meyer, Klas
A1 - Paul, Andrea
A1 - Kipphardt, Heinrich
A1 - Tuma, Dirk
T1 - Exploring the potential of a setup for combined quantification of hydrogen in natural gas – Raman and NMR spectroscopy
N2 - An accurate measurement of the amount fraction of hydrogen in gas mixtures is mandatory for practical applications, requiring methods that are fast, continuous, robust, and cost-effective. This study compares the performance of Raman and benchtop NMR process spectroscopy for determining the hydrogen amount fraction in gas mixtures. A setup was designed to integrate both techniques, enabling measurements of the same sample.
Tests were conducted with gravimetrically prepared gas mixtures of reference quality ranging from 1.20 cmol/mol to 85.83 cmol/mol of hydrogen. The results demonstrate that Raman spectroscopy provides superior performance, with a minimal root mean square error (RMSE) of 0.22 cmol/mol and excellent linearity. In contrast, benchtop NMR spectroscopy faced challenges, such as overlapping peaks and longer measurement times, resulting in a higher RMSE of 0.71 cmol/mol. Raman spectroscopy proves to be particularly well-suited for
practical applications due to its high accuracy and linearity. Meanwhile, benchtop NMR spectroscopy holds potential for future enhancements through ongoing technological advances, such as higher magnetic field strengths. In summary, the results from our study indicate that Raman spectroscopy is already a serviceable method for precise hydrogen quantification, whereas benchtop NMR spectroscopy can be attributed potential for future applications.
KW - Hydrogen amount fraction
KW - Raman spectroscopy
KW - NMR spectroscopy
KW - Field applicability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610093
DO - https://doi.org/10.1016/j.saa.2024.125087
SN - 1386-1425
VL - 325
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-61009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Segovia, J. J.
A1 - Tuma, Dirk
A1 - Lozano-Martín, D.
A1 - Moreau, A.
A1 - Martín, M. C.
A1 - Vega-Maza, D.
T1 - Speed of sound data and acoustic virial coefficients of two binary (N2 + H2) mixtures at temperatures between (260 and 350) K and at pressures between (0.5 and 20) MPa
N2 - This work aims to address the technical concerns related to the thermodynamic characterization of gas mixtures blended with hydrogen for the implementation of hydrogen as a new energy vector. For this purpose, new experimental speed of sound measurements have been done in gaseous and supercritical phases of two binary mixtures of nitrogen and hydrogen using the most accurate technique available, i.e., the spherical acoustic resonator, yielding an experimental expanded (k = 2) uncertainty of only 220 parts in 106 (0.022%). The measurements cover the pressure range between (0.5 and 20) MPa, the temperature range between (260 and 350) K, and the composition range with a nominal mole percentage of hydrogen of (5 and 10) mol%, respectively.
From the speed of sound data sets, thermophysical properties that are relevant for the characterization of the mixture, namely the second βa and third γa acoustic virial coefficients, are derived. These results are thoroughly compared and discussed with the established reference mixture models valid for mixtures of nitrogen and hydrogen, such as the AGA8-DC92 EoS, the GERG-2008 EoS, and the recently developed adaptation of the GERG-2008 EoS, here denoted GERG-H2_improved EoS. Special attention has been given to the effect of hydrogen concentration on those properties, showing that only the GERG-H2_improved EoS is consistent with the data sets within the experimental uncertainty in most measuring conditions.
KW - Speed of sound
KW - Acoustic resonance
KW - Binary gas mixture
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551482
DO - https://doi.org/10.1016/j.jct.2022.106791
SN - 0021-9614
VL - 171
SP - 1
EP - 13
PB - Elsevier B. V.
CY - Amsterdam
AN - OPUS4-55148
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erler, A.
A1 - Riebe, D.
A1 - Beitz, T.
A1 - Löhmannsröben, H.-G.
A1 - Leenen, M.
A1 - Pätzold, S.
A1 - Ostermann, Markus
A1 - Wójcik, M.
T1 - Mobile Laser-Induced Breakdown Spectroscopy for Future Application in Precision Agriculture—A Case Study
N2 - In precision agriculture, the estimation of soil parameters via sensors and the creation of nutrient maps are a prerequisite for farmers to take targeted measures such as spatially resolved fertilization. In this work, 68 soil samples uniformly distributed over a field near Bonn are investigated using laser-induced breakdown spectroscopy (LIBS). These investigations include the determination of the total contents of macro- and micronutrients as well as further soil parameters such as soil pH, soil organic matter (SOM) content, and soil texture. The applied LIBS instruments are a handheld and a platform spectrometer, which potentially allows for the single-point measurement and scanning of whole fields, respectively. Their results are compared with a high-resolution lab spectrometer.
The prediction of soil parameters was based on multivariate methods. Different feature selection methods and regression methods like PLS, PCR, SVM, Lasso, and Gaussian processes were tested and compared. While good predictions were obtained for Ca, Mg, P, Mn, Cu, and silt content, excellent predictions were obtained for K, Fe, and clay content. The comparison of the three different spectrometers showed that although the lab spectrometer gives the best results, measurements with both field spectrometers also yield good results. This allows for a method transfer to the in-field measurements
KW - LIBS
KW - Precision agriculture
KW - Soil
KW - Multivariate methods
KW - Feature selection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580777
DO - https://doi.org/10.3390/s23167178
VL - 23
IS - 16
SP - 1
EP - 17
PB - MDPI AG
CY - Basel, Schweiz
AN - OPUS4-58077
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Even, Morgane
A1 - Juritsch, Elevtheria
A1 - Richter, Matthias
T1 - On the use of Carbograph 5TD as an adsorbent for sampling VVOCs: validation of an analytical method
N2 - A standardised method for the analysis of very volatile organic compounds (VVOCs) in indoor air is still missing. This study evaluates the use of Carbograph 5TD as an adsorbent for 60 compounds (47 VVOCs + 13 VOCs) by comparing their recoveries with different spiking modes. The influence of the spiking of the tubes in dry nitrogen, humidified air or along the whole flushing duration mimicking real sampling was investigated. 49 substances (36 VVOCs from C1 to C6) had recoveries over 70% on the adsorbent in humidified air and were validated. The linearity of the calibration curves was verified for every spiking mode and the limits of detection (LOD) and quantification (LOQ) were determined. The LOQs were lower than the existing indoor air guideline values. The robustness of the method was considered by studying the influence of the sampling volume, the sampling flow rate, the humidity level and the storage of the tubes. In general, the most volatile or polar substances were the less robust ones. The combined measurement uncertainty was calculated and lies below 35% for a vast majority of the substances. An example of an emission chamber test using polyurethane foam is shown: Carbograph 5TD performs much better than Tenax® TA for VVOCs and emissions from n-butane were quantified with combined measurement uncertainty.
KW - VVOC
KW - Gas chromatography
KW - Thermal desorption
KW - Air sampling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581113
DO - https://doi.org/10.1039/D3AY00677H
VL - 15
IS - 31
SP - 3810
EP - 3821
AN - OPUS4-58111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Andrea
ED - Reese, M.
ED - Goldhammer, T.
ED - Schmalsch, C.
ED - Weber, J.
ED - Bannick, C. G.
T1 - Spectroscopic evidence for adsorption of natural organic matter on microplastics
N2 - The interaction of microcroplastics (MP) with dissolved organic matter, especially humic substances, is of great importance in understanding the behavior of microplastics in aquatic ecosystems. Surface modification by humic substances plays an essential role in transport and interaction of MP with abiotic and biotic components. Previous studies on the interaction between MP and humic substances were largely based on a model compound, humic acid (Sigma-Aldrich). In our work, we therefore investigated the interaction of natural organic matter (NOM) sampled from a German surface water with low-density polyethylene particles (LDPE). Highpressure size exclusion chromatography (HPSEC) and UV/vis absorption and fluorescence spectroscopy were used to characterize the incubation solutions after modifications due to the presence of LDPE, and Raman spectroscopy was used to characterize the incubated microplastics. While the studies of the solutions generally showed only very small effects, Raman spectroscopic studies allowed clear evidence of the binding of humic fractions to MP. The comparison of the incubation of NOM and a lignite fulvic acid which also was tested further showed that specific signatures of the humic substances used could be detected by Raman spectroscopy. This provides an elegant opportunity to conduct broader studies on this issue in the future.
KW - Humic matter
KW - Raman
KW - HPSEC
KW - Fluorescence
KW - MCR
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574519
DO - https://doi.org/10.1002/appl.202200126
SN - 2702-4288
VL - 3
IS - 2
SP - 1
EP - 30
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winckelmann, Alexander
A1 - Roik, Janina
A1 - Recknagel, Sebastian
A1 - Abad Andrade, Carlos Enrique
A1 - You, Zengchao
T1 - Investigation of matrix effects in nitrogen microwave inductively coupled atmospheric-pressure plasma mass spectrometry (MICAP-MS) for trace element analysis in steels
N2 - We investigated the performance of nitrogen microwave inductively coupled atmospheric-pressure plasma mass spectrometry (MICAP-MS) under matrix effects and its applicability to trace element analysis in steels. Influences of different gas flows and ion optics on the matrix tolerance are studied, indicating that nebulizer gas flow has the most significant impact. Optimization of ion optics improves matrix tolerance for light elements due to the reduction of the inelastic collisional scattering effect. With optimized operating conditions, MICAP-MS achieves an internal standard intensity recovery of over 90% at an Fe concentration of 500 mg L−1. Even at an Fe concentration of 1 g L−1, the recovery remains above 80%. Three certified reference materials – non-alloy, low-alloy and high-alloy steel – were analyzed using MICAP-MS. The determined mass concentrations of the trace and minor components show metrological compatibility to the reference values. No significant differences are observed between the results obtained with aqueous and matrix-matched calibration, demonstrating the strong matrix tolerance of MICAP-MS, and its promising applicability to steel analysis.
KW - MICAP-MS
KW - Trace Analysis
KW - Steel
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576323
DO - https://doi.org/10.1039/d3ja00088e
SN - 0267-9477
VL - 38
IS - 6
SP - 1253
EP - 1260
PB - Royal Society of Chemistry
AN - OPUS4-57632
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maiwald, Michael
T1 - Metrologie für fortschrittliche Wasserstoffspeicherlösungen – Das EU-Projekt MefHySto
T1 - Metrology for advanced hydrogen storage solutions – The EU project MefHySto
N2 - Das europäische Projekt MefHySto befasst sich mit dem Bedarf an großmaßstäblichen Energiespeichern, die für eine Umstellung der Energieversorgung auf erneuerbare Energien erforderlich sind. Eine solche Speicherung ist entscheidend, um Energie zu Spitzenzeiten zu liefern, wenn die erneuerbaren Energiequellen schwanken. Eine mögliche Lösung für die Energiespeicherung ist der großtechnische Einsatz von Wasserstoff. Die messtechnische Rückführbarkeit in der Energieinfrastruktur für die Wasserstoffspeicherung ist dann von entscheidender Bedeutung und eine bessere Kenntnis der chemischen und physikalischen Eigenschaften von Wasserstoff sowie rückführbare Messungen und validierte Techniken unverzichtbar.
N2 - The European project MefHySto addresses the need of large-scale energy storage, which is required for a shift to renewable energy supply. Such storage is mandatory to supply energy at peak times when renewable sources fluctuate. A possible solution for energy storage is large-scale use of hydrogen. Metrological traceability in the energy infrastructure for hydrogen storage is then crucial and a better knowledge of the chemical and physical properties of hydrogen as well as traceable measurements and validated techniques are indispensable.
KW - Wasserstoff
KW - Wasserstoffspeicher
KW - Infrastruktur
KW - Metrologie
KW - PEM-Wasserelektrolyse
KW - Rückverstromung
KW - Lastwechsel
KW - Wasserstoff-Qualität
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556451
UR - https://gwf-gas.de/forschung-entwicklung/metrologie-fuer-fortschrittliche-wasserstoffspeicherloesungen-das-eu-projekt-mefhysto/
SN - 2366-9594
VL - 163
IS - 9
SP - 38
EP - 45
PB - Vulkan Verlag
CY - Essen
AN - OPUS4-55645
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bornemann-Pfeiffer, Martin
A1 - Meyer, Klas
A1 - Lademann, J.
A1 - Kraume, M.
A1 - Maiwald, Michael
T1 - Contributions towards variable temperature shielding for compact NMR instruments
N2 - The application of compact NMR instruments to hot flowing samples or exothermically reacting mixtures is limited by the temperature sensitivity of permanent magnets. Typically, such temperature effects directly influence the achievable magnetic field homogeneity and hence measurement quality. The internal-temperature control loop of the magnet and instruments is not designed for such temperature compensation. Passive insulation is restricted by the small dimensions within the magnet borehole. Here, we present a design approach for active heat shielding with the aim of variable temperature control of NMR samples for benchtop NMR instruments using a compressed airstream which is variable in flow and temperature. Based on the system identification and surface temperature measurements through thermography, a model predictive control was set up to minimise any disturbance effect on the permanent magnet from the probe or sample temperature. This methodology will facilitate the application of variable-temperature shielding and, therefore, extend the application of compact NMR instruments to flowing sample temperatures that differ from the magnet temperature.
KW - Benchtop NMR
KW - Continuous Processes
KW - Inline Analytics
KW - Model Predictive Control
KW - Process Analytical Tecnology
KW - Temperature Control
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579219
DO - https://doi.org/10.1002/mrc.5379
SN - 1097-458X
SP - 1
EP - 10
PB - John Wiley & Sons Ltd.
AN - OPUS4-57921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Musyanovych, A.
A1 - Grimmer, Christoph
A1 - Sadak, A. E.
A1 - Heßling, L.
A1 - Lüdicke, M.
A1 - Bilsel, M.
A1 - Horn, Wolfgang
A1 - Richter, Matthias
T1 - Polymer Capsules with Volatile Organic Compounds as Reference Materials for Controlled Emission
N2 - Encapsulation of volatile organic compounds (VOCs) that could evaporate at a defined rate is of immense interest for application in emission reference materials (ERMs). Polyurethane/polyurea microcapsules with various VOC active ingredients (limonene, pinene, and toluene) were successfully produced by interfacial polymerization with Shirasu porous glass membrane emulsification in a size range between 10 and 50 μm. The effect of surfactant, VOC, monomer(s) type, and ratio has a great effect on the formulation process and morphology of capsules. The type of VOC played a significant role in the encapsulation efficiency. Due to the difference in vapor pressure and VOC/water interfacial tension, the formulation for encapsulation was optimized for each individual VOC. Furthermore, to achieve effective stability of the large droplets/capsules, a combination of ionic and nonionic surfactants was used. Optical and scanning electron microscopy, Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA), were used to characterize the optimized microcapsules. The results showed that the obtained microcapsules exhibited a spherical shape and core–shell morphology and featured characteristic urethane-urea bonds. The amount of encapsulated VOC ranges between 54 and 7 wt %. The emission tests were performed with the help of the emission test chamber procedure (EN 16516). The limonene-loaded polyurethane/polyurea microcapsules show a change in emission rate of less than 10% within 14 days and can be considered as a potential candidate for use as an ERM.
KW - Polymer microcapsules
KW - Membrane emulsification
KW - Polyaddition
KW - Volatile organic compound (VOC)
KW - Emission testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-619227
DO - https://doi.org/10.1021/acsami.4c12826
SN - 1944-8252
VL - 16
IS - 50
SP - 69999
EP - 70009
PB - ACS
AN - OPUS4-61922
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiele, Isabel
A1 - Weiske, Björn
A1 - Riedel, Sebastian L.
A1 - Meyer, Klas
T1 - On-line monitoring of polyhydroxyalkanoate extraction by low-field nuclear magnetic resonance spectroscopy
N2 - The use of low-field nuclear magnetic resonance (NMR) spectroscopy enables real-time reaction monitoring in contrast to time-consuming gas chromatography or off-line high-field NMR measurements. In this study, NMR spectroscopy is demonstrated as a novel process analytical technology (PAT) tool in the downstream processing of polyhydroxyalkanoate (PHA) biopolymers. On-line NMR spectroscopy measurements were performed using a Spinsolve 43 Carbon Ultra instrument in a fully automated mode with a flow-assembly based on PTFE tubing. Single-scan NMR spectra were acquired for real-time monitoring of the extraction process of the PHA copolymer poly(hydroxybutyrate-co-hydroxyhexanoate) with 13.5 mol.% hydroxyhexanoate [P(HB-co-13.5 mol.%HHx)] from Ralstonia eutropha biomass using chloroform or acetone as PHA solvents at lyophilized cell loadings of 20–120 g L 1. The reproducibility and reliability of low-field NMR spectroscopy was comparable to high-field NMR spectroscopy, with superior performance in terms of time. The correlation between the results of on-line monitoring using low-field NMR spectroscopy and off-line analysis using gas chromatography (GC) showed a correlation coefficient of >94 %. The versatility of low-field NMR spectroscopy for elucidating reaction kinetics, facilitating endpoint determination and accelerating extraction processes by maximizing solubility is highlighted as plateau values were reached within 6–10 min for chloroform and acetone, respectively. This novel low-field NMR spectroscopy application promotes a new monitoring approach for downstream PHA processing and supports process development and optimization.
KW - Polyhydroxyalkanoate
KW - Extraction
KW - NMR
KW - Ralstonia eutropha
KW - Downstream processing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624215
DO - https://doi.org/10.1016/j.polymdegradstab.2025.111188
SN - 1873-2321
VL - 233
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-62421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mervič, Kristina
A1 - Azimzada, Agil
A1 - Bayat, Mehmet Emin
A1 - Šala, Martin
A1 - Meermann, Björn
T1 - CO2-based matrix-independent carbon quantification approach for single microplastic-ICP-MS analysis
N2 - This study presents a new CO2-based, matrix-independent calibration approach for size determination of microplastic (MP) particles using single particle inductively coupled plasma-mass spectrometry (sp-ICP-MS). By incorporating a CO2 gas calibration approach and upon adjusting the flow rates, an accurate size determination of MPs between 2 and 7 μm was enabled. Scanning electron microscopy (SEM) was successfully applied for method validation. The CO2 gas calibration curves exhibited excellent linearity and reproducibility, with minimal matrix effects across different sample types and matrices, including river water and saline solutions. This CO2-based approach eliminates the limitations of matrix- and size-dependent calibrations, enabling robust and accurate size determinations of MPs. This advancement represents a significant step forward in the analytical capabilities for MPs, paving the way for improved environmental monitoring and assessment of plastic pollution.
KW - sp-ICP-MS
KW - Microplastic
KW - New calibration strategy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633049
DO - https://doi.org/10.1007/s00216-025-05934-9
SN - 1618-2642
SP - 1
EP - 11
PB - Springer
CY - Berlin
AN - OPUS4-63304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Krom, I.
A1 - Heikens, D.
A1 - Horn, Wolfgang
A1 - Wilke, Olaf
A1 - Richter, Matthias
A1 - Baldan, A.
T1 - Metrological generation of SI-traceable gas-phase standards and reference materials for (semi-) volatile organic compounds
N2 - EN 16516 sets specifications for the determination of emissions into indoor air from construction products. Reliable, accurate and International System of Unit (SI)-traceable measurement results of the emissions are the key to consumer protection. Such measurement results can be obtained by using metrologically traceable reference materials. Gas-phase standards of volatile organic compounds (VOCs) in air can be prepared by a variety of dynamic methods according to the ISO 6145 series. However, these methods are not always applicable for semi-VOCs (SVOCs) due to their high boiling point and low vapour pressure. Therefore, a novel dynamic gas mixture generation system has been developed. With this system gas-phase standards with trace level VOCs and SVOCs in air can be prepared between 10 nmol mol−1 and 1000 nmol mol−1. The VOCs and SVOCs in this study have normal boiling points ranging from 146 °C to 343 °C. Metrologically traceable reference materials of the gas-phase standard were obtained by sampling of the VOC gas-phase standard into Tenax TA® sorbent material in SilcoNert® coated stainless steel tubes. Accurately known masses between 10 ng and 1000 ng per VOC were sampled. These reference materials were used to validate the dynamic system. Furthermore, the storage and stability periods of the VOCs in the reference materials were determined as these are crucial characteristics to obtain accurate and SI-traceable reference materials. In a round robin test (RRT), the reference materials were used with the aim of demonstrating the feasibility of providing SI-traceable standard reference values for SVOCs for interlaboratory comparison purposes. Based on the results from the validation, the storage and stability studies and the RRT, gas-phase standards and reference materials of VOCs and SVOCs with relative expanded uncertainties between 5% and 12% (k = 2) have been developed. These reference standards can be used as calibrants, reference materials or quality control materials for the analysis of VOC emissions.
KW - SVOC
KW - Dynamic calibration gas mixtures
KW - Reference materials
KW - Indoor air
KW - Thermal desorption
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565978
DO - https://doi.org/10.1088/1361-6501/aca704
VL - 34
IS - 3
SP - 1
EP - 13
PB - IOP Publishing
AN - OPUS4-56597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Moutaouakil, H.
A1 - Heimann, Jan
A1 - Lozano, Daniel
A1 - Memmolo, V.
A1 - Schütze, A.
T1 - Feature Extractor for Damage Localization on Composite-Overwrapped Pressure Vessel Based on Signal Similarity Using Ultrasonic Guided Waves
N2 - Hydrogen is one of the future green energy sources that could resolve issues related to fossil fuels. The widespread use of hydrogen can be enabled by composite-overwrapped pressure vessels for storage. It offers advantages due to its low weight and improved mechanical performance. However, the safe storage of hydrogen requires continuous monitoring. Combining ultrasonic guided waves with interpretable machine learning provides a powerful tool for structural health monitoring. In this study, we developed a feature extraction approach based on a similarity method that enables interpretability in the proposed machine learning model for damage detection and localization in pressure vessels. Furthermore, a systematic optimization was performed to explore and tune the model’s parameters. This resulting model provides accurate damage localization and is capable of detecting and localizing damage on hydrogen pressure vessels with an average localization error of 2 cm and a classification accuracy of 96.5% when using quantized classification. In contrast, binarized classification yields a higher accuracy of 99.5%, but with a larger localization error of 6 cm.
KW - Ultrasonic Guided Waves
KW - Composite Overwrapped Pressure Vessel
KW - Interpretable Machine Learning
KW - Structural Health Monitoring
KW - Damage Localization
KW - Critical Infrastructure
KW - Hydrogen
KW - Non-destructive Testing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640249
DO - https://doi.org/10.3390/app15179288
VL - 15
IS - 17
SP - 1
EP - 20
PB - MDPI
AN - OPUS4-64024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Colombo, Marta
A1 - Mostoni, Silvia
A1 - Fredi, Giulia
A1 - Rodricks, Carol
A1 - Kalinka, Gerhard
A1 - Riva, Massimiliano
A1 - Vassallo, Andrea
A1 - Di Credico, Barbara
A1 - Scotti, Roberto
A1 - Zappalorto, Michele
A1 - D'Arienzo, Massimiliano
T1 - Interfacial Chemistry Behind Damage Monitoring in Glass Fiber‐Reinforced Composites: Attempts and Perspectives
N2 - Glass Fiber Reinforced Polymers (GFRPs) are widely used in structural applications but degrade over time due to internal damage. Structural Health Monitoring (SHM) enables early damage detection, improving reliability and reducing maintenance costs. Traditional SHM methods are often invasive and expensive. An emerging solution involves the embedding of carbon‐based filler like carbon nanotubes and reduced graphene oxide into GFRPs, forming conductive networks that detect damage through resistance changes. However, poor adhesion among GF, filler, and matrix can reduce mechanical performance. Therefore, tailoring GF and filler surface chemistry is essential to enhance durability and enable effective self‐sensing properties. This review summarizes the most recent efforts in modifying GF with carbon‐based filler to design GFRP with improved sensing ability and mechanical performance. After a brief introduction on the role of SHM solutions in early damage detection, an overview of the common GF and filler used in GFRPs will be provided. Then, the most relevant GF modification strategies exploited to incorporate carbon‐based filler in GFRPs will be described, focusing on the chemical grafting approach, which allows a careful optimization of the fiber/matrix interface. Last, a concise summary of the key mechanical and electrical tests to evaluate interfacial adhesion and self‐sensing will be supplied.
KW - Review
KW - Interface
KW - Micromechanics
KW - Polymer matrix composites
KW - Glass fibre reinforced composites
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639934
DO - https://doi.org/10.1002/pc.70332
SN - 0272-8397
SP - 1
EP - 30
PB - Wiley
AN - OPUS4-63993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkler, Nicolas P.
A1 - Kotlyar, O.
A1 - Schaffernicht, E.
A1 - Matsukura, H.
A1 - Ishida, H.
A1 - Neumann, Patrick P.
A1 - Lilienthal, A. J.
T1 - Super-resolution for Gas Distribution Mapping
N2 - Gas Distribution Mapping (GDM) is a valuable tool for monitoring the distribution of gases in a wide range of applications, including environmental monitoring, emergency response, and industrial safety. While GDM is actively researched in the scope of gas-sensitive mobile robots (Mobile Robot Olfaction), there is a potential for broader applications utilizing sensor networks. This study aims to address the lack of deep learning approaches in GDM and explore their potential for improved mapping of gas distributions. In this paper, we introduce Gas Distribution Decoder (GDD), a learning-based GDM method. GDD is a deep neural network for spatial interpolation between sparsely distributed sensor measurements that was trained on an extensive data set of realistic-shaped synthetic gas plumes based on actual airflow measurements. As access to ground truth representations of gas distributions remains a challenge in GDM research, we make our data sets, along with our models, publicly available. We test and compare GDD with state-of-the-art models on synthetic and real-world data. Our findings demonstrate that GDD significantly outperforms existing models, demonstrating a 35% improvement in accuracy on synthetic data when measured using the Root Mean Squared Error over the entire distribution map. Notably, GDD appears to have superior capabilities in reconstructing the edges and characteristic shapes of gas plumes compared to traditional models. These potentials offer new possibilities for more accurate and efficient environmental monitoring, and we hope to inspire other researchers to explore learning-based GDM.
KW - Gas distribution mapping
KW - Spatial interpolation
KW - Sensor networks
KW - Deep learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607786
DO - https://doi.org/10.1016/j.snb.2024.136267
SN - 0925-4005
VL - 419
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-60778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bubel, Martin
A1 - Schmid, Jochen
A1 - Carmesin, Maximilian
A1 - Kozachynskyi, Volodymyr
A1 - Esche, Erik
A1 - Bortz, Michael
T1 - Cubature-based uncertainty estimation for nonlinear regression models
N2 - Models are commonly utilized in chemical engineering to simulate real-world processes and phenomena. Given their role in guiding decision-making, accurately quantifying the uncertainty of these models is essential. Typically, these models are calibrated using experimental data that contain measurement errors, leading to uncertainty in the fitted model parameters. Current methods for estimating the prediction uncertainty of nonlinear regression models are often either computationally intensive or biased. In this study, we use sparse cubature formulas to estimate the prediction uncertainty of nonlinear regression models. Our findings indicate that this method provides a favorable balance between accuracy and computational efficiency, making it suitable for application in chemical engineering. We validate the performance of our proposed method through various regression case studies, including both theoretical toy models and practical models from chemical engineering.
KW - Nonlinear models
KW - Model uncertainty
KW - Parameter estimation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628008
DO - https://doi.org/10.1016/j.compchemeng.2025.109035
SN - 1873-4375
VL - 197
SP - 1
EP - 23
PB - Elsevier Ltd.
AN - OPUS4-62800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tobias, Charlie
A1 - Gehrenkemper, Lennart
A1 - Bernstein, Thomas
A1 - Schlau, Sven
A1 - Simon, Fabian
A1 - Röllig, Mathias
A1 - Meermann, Björn
A1 - von der Au, Marcus
T1 - Development of a fully automated slurry sampling introduction system for GF-AAS and its application for the determination of cadmium in different matrices
N2 - element analysis, offering high sensitivity and precision. However, its effectiveness is limited by sample preparation challenges for solid samples like soils and microplastics. Traditional methods include sample preparation, such as digestion, which is time-consuming and involves reagents, like acids, contributing to measurement uncertainty and higher carbon footprints. Slurry sampling allows direct analysis of suspensions, offering a more efficient alternative. However, maintaining suspension stability is challenging, requiring robust autosampler systems to streamline the process and enhance analytical performance.
Results: We present a novel autosampler extension for slurry sample introduction into GF-AAS. This system ensures suspension stability with a stirring device and closed vessels to prevent evaporation and contamination, incorporating a cooling unit to reduce solvent and analyte losses. It installs and removes in minutes without
additional connections. Validation with cadmium analysis in BAM-U110 (Soil) and BAM-H010 (ABS) showed high reliability. For BAM-U110 (Soil), we achieved recovery rates of 94 % ± 13 % in water suspension. The recovery rate for BAM-H010 (ABS) was 104 % ±11 % in acetonitrile suspension. These results demonstrate the system’s robustness, versatility, and accuracy for different matrices.
Significance:
The autosampler extension helps solve key problems in trace element analysis of solid samples, making the process faster and more accurate. It works well with complex materials, making it useful for areas like microplastic or nanoparticle analysis. This improvement also helps meet regulations for monitoring environ mental and polymer samples, offering a reliable and flexible tool for high-throughput analysis with fewer errors.
KW - Slurry AAS
KW - Soil
KW - Cd
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618531
DO - https://doi.org/10.1016/j.aca.2024.343460
SN - 0003-2670
VL - 1335
SP - 1
EP - 7
PB - Elsevier BV
AN - OPUS4-61853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hülagü, Deniz
A1 - Ermilova, Elena
A1 - Weise, Matthias
A1 - de Préville, Sophie
A1 - Hoffmann, Johannes
A1 - Morán‐Meza, José
A1 - Piquemal, François
A1 - Hertwig, Andreas
T1 - Multimethod Electrical Characterization of Thin Indium Tin Oxide Films: Structuring and Calibration Sample Development for Scanning Probe Microscopy
N2 - Indium tin oxide (ITO), a transparent conductive oxide, is widely used in optoelectronic applications due to its electrical conductivity, optical transparency, and chemical stability. This study employs spectroscopic ellipsometry (SE) to analyze ITO layers, enabling nondestructive determination of film thickness, dielectric functions, and bulk conductivity. Electrical properties derived from SE are compared with those obtained using the four‐point probe method (4PM) to improve metrological tools for nanotechnology applications and optimize deposition process monitoring for better control of film properties. This work also investigates the chemical stability of ITO layers under etching conditions and explores the development of new sheet resistance standards for scanning microwave microscopy (SMM). The results show that ITO resistivity, calculated from fitted SE data, increases with oxygen flow rate up to 5 cm3(STP) min−1. Good agreement is observed between sheet resistance values obtained by SE and 4PM up to 3 cm3(STP) min−1. Additionally, the sheet resistance values of a distinct set of microstructured ITO samples with different ITO layer thicknesses are determined by SMM, which are highly consistent with those obtained by the 4PM.
KW - Ellipsometry
KW - Indium tin oxide (ITO)
KW - Scanning microwave microscopy (SMM)
KW - Sheet resistance calibration standards
KW - ITO wet etching
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626242
DO - https://doi.org/10.1002/pssa.202400871
SN - 1862-6300
VL - 222
IS - 14
SP - 1
EP - 18
PB - Wiley
CY - Hoboken, New Jersey, USA
AN - OPUS4-62624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munzke, Dorit
A1 - Duffner, Eric
A1 - Eisermann, René
A1 - Schukar, Marcus
A1 - Schoppa, André
A1 - Szczepaniak, Mariusz
A1 - Strohhäcker, J.
A1 - Mair, Georg W.
T1 - Monitoring of type IV composite pressure vessels with multilayer fully integrated optical fiber based distributed strain sensing
N2 - We present the results of distributed fiber optic strain sensing for condition monitoring of a hybrid type IV composite fully wrapped pressure vessel using multilayer integrated optical fibers. Distributed strain sensing was performed for a total number of 252,000 load cycles until burst of the vessel. During this ageing test material fatigue could be monitored and spatially localized. Critical material changes were detected 17,000 cycles before material failure. Results have been validated by acoustic emission analysis.
T2 - 12th International Conference on Composite Science and Technology (ICCST12)
CY - Sorrento, Italy
DA - 08.05.2019
KW - Hybrid composite pressure vessel
KW - Distributed fiber optic sensing
KW - Acoustic emission analysis
KW - Structural health monitoring
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516772
DO - https://doi.org/10.1016/j.matpr.2020.02.872
SN - 2214-7853
VL - 34
SP - 217
EP - 223
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-51677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mair, Georg W.
ED - Rockland, U.
T1 - Neue Ansätze für die sichere Auslegung von Treibgasspeichern - Probabilistik und Risikoansatz
N2 - Die Beurteilung neuer Techniken bezüglich der Gefährdung
von Dritten wird immer weniger mit Hilfe traditioneller, auf
Erfahrung und Iteration basierenden Betrachtungsweisen
hinreichend möglich. Deshalb werden zunehmend probabilistische
Analysen und Risikobetrachtungen erforderlich. Diese
Verfahren bieten zudem die Möglichkeiten, ein System
z. B. gegenüber Eigengewicht oder Wartungsaufwand bei
gleicher oder auch besserer Sicherheit zu optimieren.
Vor diesem Hintergrund werden zunächst die Begriffe Risiko
und Chance bzw. Gefahr und Sicherheit erläutert.
Am Beispiel von Treibgasspeichern wie sie auch für die
Speicherung von Wasserstoff in Fahrzeugen eingesetzt werden
wird gezeigt, dass die bisherige, deterministische
Betrachtungsweise von Druckbehältern und deren statische
Sicherheit (z. B. gegen Bersten) kein hinreichendes Maß der
Sicherheit als Gegenteil von Gefahr darstellt oder sogar
irreführend für die richtige Einschätzung ist.
T2 - 10. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Deutschland
DA - 2004-06-17
PY - 2004
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-48481
SP - 35
EP - 38
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-4848
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eisermann, René
A1 - Basedau, Frank
A1 - Kadoke, Daniel
A1 - Gründer, Peter
A1 - Schoppa, André
A1 - Lehr, Christian
A1 - Szczepaniak, Mariusz
A1 - John, Sebastian
A1 - Schukar, Marcus
A1 - Munzke, Dorit
A1 - Mair, Georg W.
T1 - Distributed strain sensing with sub-centimetre resolution for the characterisation of structural inhomogeneities and material degradation of industrial high-pressure composite cylinders
N2 - Fibre-reinforced plastics (FRP) especially carbon-fibre-reinforced polymer (CFRP) and glass-fibre-reinforced polymer (GFRP) are commonly used materials in high pressure vessels and storage units for automotive and aerospace purposes. Optical fibres are suitable to be integrated or directly applied to the surface of FRP components. Using optical fibres it is possible to monitor the distributed strain profiles and changes within the fatigue life of a pressure vessel to ensure the operational safety. Within artificial ageing experiments we used swept wavelength interferometry (SWI) based distributed strain sensing for the monitoring of commercial high-pressure composite cylinder. This artificial ageing was performed using test conditions of 503bar pressure load (service pressure 300 bar) and 89 °C for 100 h. The polyimide coated optical fibres were glued to the surface externally in circumferential and axial direction. Using distributed strain sensing (DSS) material expansion of over 0.5% were monitored with sub-centimetre spatial resolution. Within the circumferential direction we observed up to 10 % local fluctuation compared to the median strain caused by inhomogeneous material expansion, which could cause local material fatigue. In addition, we determined material degradation manifested itself as localized remaining material expansion and/or contraction. Results have been validated by other non-destructive methods like digital strip projection.
T2 - 9th European Workshop on Structural Health Monitoring (EWSHM)
CY - Manchester, UK
DA - 10.07.2018
KW - Distributed fibre optic sensors
KW - Optical backscatter reflectometry
KW - Swept wavelength interferometry (SWI)
KW - Structural health monitoring (SHM)
KW - Composite structures
KW - Optical fibre
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458926
SP - 1
EP - 8
AN - OPUS4-45892
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mair, Georg W.
A1 - Thomas, Sebastian
A1 - Schalau, Bernd
A1 - Wang, Bin
T1 - Safety criteria for the transport of hydrogen in permanently mounted composite pressure vessels
N2 - The recent growth of the net of hydrogen fuelling stations increases the demands to transport compressed hydrogen on road by battery vehicles or tube-trailers, both in composite pressure vessels. As a transport regulation, the ADR is applicable in Europe and adjoined regions, and is used for national transport in the EU. This regulation provides requirements based on the behaviour of each individual pressure vessel, regardless of the pressure of the transported hydrogen and relevant consequences resulting from generally possible worst case scenarios such as sudden rupture. In 2012, the BAM (German Federal Institute for Materials Research and Testing) introduced consequence-dependent requirements and established them in national transport requirements concerning the “UN service life checks” etc. to consider the transported volume and pressure of gases. This results in a requirement that becomes more restrictive as the product of pressure and volume increases. In the studies presented here, the safety measures for hydrogen road transport are identified and reviewed through a number of safety measures from countries including Japan, the USA and China. Subsequently, the failure consequences of using trailer vehicles, the related risk and the chance are evaluated. A benefit-related risk criterion is suggested to add to regulations and to be defined as a safety goal in standards for hydrogen transport vehicles and for mounted pressure vessels. Finally, an idea is given for generating probabilistic safety data and for highly efficient evaluation without a significant increase of effort.
T2 - ICHS 2019
CY - Adelaide, Australia
DA - 24.09.2019
KW - F-N-diagram
KW - Chance-risk analysis
KW - Pressure-volume product
KW - Limit of acceptable consequence
KW - Minimum burst pressure
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511589
DO - https://doi.org/10.1016/j.ijhydene.2020.07.268
SN - 0360-3199
VL - 46
IS - 23
SP - 12577
EP - 12593
PB - Elsevier Ltd.
AN - OPUS4-51158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Niebergall, Ute
A1 - Marschall, Niklas
A1 - Meinel, Dietmar
A1 - Böhning, Martin
T1 - Relation of craze to crack length during slow crack growth phenomena in high‐density polyethylene
N2 - The craze‐crack mechanism occurring in high‐density polyethylene (HDPE) causing slow crack growth and environmental stress cracking is investigated in detail with respect to the relation of crack length and the related craze zone. This is essential for the understanding of the resulting features of the formed fracture surface and their interpretation in the context of the transition from crack propagation to ductile shear deformation. It turns out that an already formed craze zone does not inevitably result in formation of a propagating crack, but could also undergo ductile failure. For the examination, the full notch creep test (FNCT) was employed with a subsequent advanced fracture surface analysis that was performed using various imaging techniques: light microscopy, laser scanning microscopy, scanning electron microscopy, and X‐ray micro computed tomography scan. FNCT specimens were progressively damaged for increasing durations under standard test conditions applying Arkopal, the standard surfactant solution, and biodiesel as test media were used to analyze the stepwise growth of cracks and crazes. From considerations based on well‐established fracture mechanics approaches, a theoretical correlation between the length of the actual crack and the length of the preceding craze zone was established that could be evidenced and affirmed by FNCT fracture surface analysis. Moreover, the yield strength of a HDPE material exposed to a certain medium as detected by a classic tensile test was found to be the crucial value of true stress to induce the transition from crack propagation due to the craze‐crack mechanism to shear deformation during FNCT measurements.
Highlights
- Progress of crack formation in high‐density polyethylene is analyzed by different imaging techniques
- Determined growth rates depend on distinction between craze zone and crack
- The ratio of the present crack to the anteceding craze zone is validated theoretically
- The transition from crack propagation to ductile shear deformation is identified
- An already formed craze zone may still fail by ductile mechanisms
KW - Craze-crack mechanism
KW - Environmental stress cracking (ESC)
KW - Full notch creep test (FNCT)
KW - Laser scanning microscopy (LSM)
KW - Slow crack growth (SCG)
KW - X-ray computed tomography (CT)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601831
DO - https://doi.org/10.1002/pen.26698
SN - 1548-2634
VL - 64
IS - 6
SP - 2387
EP - 2403
PB - Wiley
AN - OPUS4-60183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thuy, Maximilian
A1 - Niebergall, Ute
A1 - Oehler, H.
A1 - Alig, I.
A1 - Böhning, Martin
T1 - Damaging effect of admixtures used in crop protection products on high density polyethylene packaging material
N2 - The phenomenon of environmental stress cracking is still a major issue in materials engineering as well as from a scientific perspective. Especially in the case of packaging materials made of high-density polyethylene, assessing the potential of premature damage due to environmental stress cracking is complex because of the large number of components in possible liquid filling goods. As a first guideline, the well-known effect of detergents and dispersants is usually considered, but the interplay with other components, such as organic solvents is often unknown. Particularly challenging in this respect are crop protection products, consisting of several different admixtures in addition to the biologically active ingredients. This study is based on two model liquids representing these admixtures that were established for testing in this context. The model liquids as well as their constituting components were used as liquid media in the Full Notch Creep Test to characterize the environmental stress cracking behavior of a typical high-density polyethylene. Complementary to the time-to failure of a notched specimen obtained from these tests, the crack opening was monitored optically, and the fracture surface was analyzed post-failure by laser scanning microscopy as well as scanning electron microscopy. Based on the results, the effect of various surfactants as well as the influence of organic solvents on environmental stress cracking are discussed.
KW - Environmental stress cracking
KW - High-density polyethylene
KW - Crop protection products
KW - Full notch creep test
KW - Fracture surface analysis
KW - Crack opening displacement
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554631
DO - https://doi.org/10.1016/j.polymertesting.2022.107672
SN - 0142-9418
VL - 114
SP - 1
EP - 16
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-55463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Magnier, Vincent
A1 - Dufrenoy, Philippe
T1 - Identification of damage mechanisms in a metal-matrix composite material via digital volume correlation and finite element model updating
N2 - A 3D experimental and numerical investigation of the damage mechanisms induced by compression in a metal matrix composite is presented. The investigated composite is a simplified version of those typically used for heavy-duty brake linings, comprising only nine constituents. The analysis combines laboratory X-ray computed tomography (XCT), image volume correlation (DVC), as well as image-based finite element method (FEM) paired with an inverse identification approach known as finite element model updating (FEMU). The combination of in situ XCT and DVC allows the rationalization of the mechanisms controlling strain localization and damage accumulation within the heterogeneous metal matrix. The damage mainly occurs in the form of fractured material within thin cell-walls located between large graphite G2 particles. In addition, the herein developed FEMU approach enables the identification of the elastic moduli of the two defined key constituents controlling the macroscopic compressive behavior (i.e., the Matrix –where eight of the nine constituents are lumped– and G2 particles), as well as the prediction of the damaged regions within the Matrix. It is emphasized that an implementation of the damage mechanisms within the FEMU is essential for a reliable numerical prediction of the compressive response of the composite.
KW - Metallic brake lining
KW - Compression tests
KW - In situ X-ray computed tomography (XCT)
KW - Image-based finite element method (FEM)
KW - Damage mechanisms
KW - Digital volume correlation (DVC)
KW - Finite element model updating (FEMU)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639388
DO - https://doi.org/10.1016/j.mtcomm.2025.113459
SN - 2352-4928
VL - 48
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-63938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vermeeren, Sarah
A1 - Witzler, Markus
A1 - Makarow, Ramona
A1 - Engelhard, Carsten
A1 - Kaul, Peter
T1 - Multivariate evaluation method for the detection of pest infestations on plants via VOC analysis using gas chromatography mass spectrometry
N2 - Volatile organic compounds (VOCs) play an important role in the defense against pest infestations on plants. The analysis of these VOCs using gas chromatography mass spectrometry (GC-MS) enables the detection of pests by analyzing the VOC composition (VOC profiles) for specific patterns and markers. The analysis of such complex datasets with high biovariability poses a particular challenge. For this reason, a multivariate evaluation method based on a self-written Python script, using principal component analysis (PCA) and linear discriminant analysis (LDA), was developed and tested for functionality using a dataset, which has been evaluated manually and has identified five specific markers (2,4-dimethyl-1-heptene, 3-carene, alpha-longipinene, cyclosativene, and copaene) for Anoplophora glabripennis (ALB) infestation on Acer trees. The results obtained in the present study did not only match the manually evaluated results, but lead to further insight into the dataset. Another sesquiterpene which is assumed to be alpha-zingiberene was identified as an ALB specific marker in addition to 2,4-dimethyl-1-heptene and 3-carene. Furthermore, the European native beetle species goat moth Cossus cossus (CC) and poplar long-horned beetle Saperda carcharias (SC) were also analyzed for their VOCs to differentiate ALB specific VOC from other pest infestations. This comparison lead to the conclusion that the compounds alpha-longipinene, cyclosativene, and copaene are not specific for ALB but for pest infestation in general. It was possible to identify not only specifically produced VOCs, but also differences in concentrations that arise specifically during ALB infestation. Therefore, the evaluation method for the detection of plant pests presented in this study represents a time-saving alternative to conventional non computing methods, which in addition provides more detailed results.
KW - Mass Spectrometry
KW - Gas Chromatography
KW - Volatile organic compounds
KW - Pest infestation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639526
DO - https://doi.org/10.1038/s41598-025-11607-5
SN - 2045-2322
VL - 15
IS - 1
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-63952
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santi, Alberto
A1 - Schröder, Jakob
A1 - Serrano-Munoz, Itziar
A1 - Bayat, Mohamad
A1 - Hattel, Jesper Henri
T1 - Exploring the Flash Heating method in additive manufacturing for residual stress prediction: A comparative study with diffraction results from X-ray and neutron techniques
N2 - Residual stress (RS) control is crucial for ensuring the performance and reliability of components produced through laser-based powder bed fusion (PBF-LB) additive manufacturing (AM). This study evaluates the Flash Heating (FH) method as an efficient approach for RS prediction, comparing its outcomes with multiple experimental techniques, including X-ray diffraction, neutron diffraction, and layer removal methods. These experimental assessments are conducted in different regions of the component, both before and after detachment from the baseplate. The study validates the FH method and analyzes key numerical parameters, such as meta-layer height, contact time, and time-stepping strategies. Results indicate that FH effectively predicts bulk RS distributions but shows discrepancies in surface stress estimations, likely due to unaccounted factors like surface roughness. Additionally, implementing experimentally derived material properties from as-built AM samples significantly enhances model accuracy compared to conventional material datasets. These findings underscore the potential of FH for efficient RS prediction in PBF-LB while identifying areas for further improvement. Refinements should focus on incorporating anisotropic, temperature-dependent material behavior derived from as-built AM samples and surface roughness effects. This work advances the understanding of key factors necessary for accurate and computationally efficient RS prediction, supporting the optimization of AM processes.
KW - Finete element method
KW - Inconel 718
KW - Metal additive manufacturing
KW - Residual stress
KW - Thermomechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639533
DO - https://doi.org/10.1080/01495739.2025.2541862
SN - 0149-5739
SP - 1
EP - 24
PB - Taylor & Francis
AN - OPUS4-63953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Braun, Jennifer
A1 - Engelhard, Carsten
A1 - Kaul, Peter
T1 - Optimized fast gas chromatography coupled with proton-transfer-reaction time-of-flight mass spectrometry for the selective near real-time analysis of herbivore-induced plant volatiles
N2 - The analysis of herbivore-induced plant volatiles (HIPVs) is essential for understanding plant-environment interactions and defense strategies against herbivores. Proton transfer reaction time-of-flight mass spectrometry (PTR–TOF–MS) is a powerful analytical tool that enables real-time monitoring and quantification of diverse groups of HIPVs. However, the PTR–TOF–MS technique is constrained in its ability to effectively differentiate between isomers. When analyzing complex mixtures of HIPVs, the separation of isomers becomes crucial as major compound classes such as terpenes comprise thousands of isomers. In this study, we present an optimized fast gas chromatography (fastGC) based on a modified version of the commercially available fastGC add-on integrated into a mobile PTR–TOF. The system was optimized for the analysis of emissions from enclosed trunks of Acer platanoides infested by Anoplophora glabripennis (Motschulsky), commonly known as Asian longhorned beetle (ALB). The development of fastGC was primarily focused on the sesquiterpenes α-longipinene, cyclosativene and α-copaene, which serve as strong indicators of ALB infestation. These sesquiterpenes were separated in less than three minutes, with intra-day retention time RSD < 0.6 % and resolutions of 2.6 ± 0.3 and 1.3 ± 0.2. In comparison to the original system, the optimized fastGC demonstrates more than tripled sesquiterpene resolution, twice the sensitivity relative to direct inlet mode, and an approximately 10 % reduction in total analysis time. The optimized fastGC–PTR–TOF allows for near real-time analysis of complex mixtures of biogenic VOCs, making it a powerful tool for environmental monitoring, integrated pest management, and forest protection.
KW - Mass Spectrometry
KW - PTR-TOF-MS
KW - Gas Chromatography
KW - Herbivore-induced plant volatiles
KW - Sesquiterpenes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639513
DO - https://doi.org/10.1016/j.chroma.2025.466236
SN - 0021-9673
VL - 1759
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-63951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kemmler, Samuel
A1 - Cuéllar, Pablo
A1 - Rettinger, C.
A1 - Köstler, H.
T1 - A Fluid-Solid Coupled Micromechanical Simulation for the Analysis of Piping Erosion During the Seabed Installation of a Suction Bucket Foundation
N2 - Suction buckets are a promising concept for the foundations of offshore wind turbines. During the installation process of a suction bucket, localized fluidization of the granular soil, so-called piping erosion, may lead to installation failure. A 3D fluid-solid coupled micromechanical simulation is presented to study the occurrence of piping. An Euler-Lagrangian coupling employs momentum exchange between the fluid phase and the geometrically resolved particles. We investigate the behavior of the soil for three cases with varying prescribed suction velocities. We observe piping in the case with the highest suction velocity by analyzing the deformation of the granular fabric and monitoring the differential pressure. The grains under the bucket wall-tip show the highest hydraulic gradients and forces at the onset of piping. This approach permits a detailed analysis of piping phenomena and brings novel insights on the triggering conditions for piping failure of suction-aided foundations.
T2 - TC 105 International Symposium
CY - Grenoble, France
DA - 23.09.2024
KW - Micromechanical simulation
KW - Piping erosion
KW - Suction bucket foundation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629461
DO - https://doi.org/10.1088/1755-1315/1480/1/012024
SN - 1755-1307
VL - 1480
IS - 1
SP - 1
EP - 4
PB - IOP Publishing
AN - OPUS4-62946
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erxleben, Kjell
A1 - Kaiser, Sebastian
A1 - Rhode, Michael
A1 - Kannengiesser, Thomas
A1 - Kromm, Arne
T1 - In-service and repair welding of pressurized hydrogen pipelines–a review on current challenges and strategies
N2 - Hydrogen is the energy carrier for a sustainable future without fossil fuels. As this requires a reliable transportation infrastructure, the conversion of existing natural gas (NG) grids is an essential part of the worldwide individual national hydrogen strategies, in addition to newly erected pipelines. In view of the known effect of hydrogen embrittlement, the compatibility of the materials already in use (typically low-alloy steels in a wide range of strengths and thicknesses) must be investigated. Initial comprehensive studies on the hydrogen compatibility of pipeline materials indicate that these materials can be used to a certain extent. Nevertheless, the material compatibility for hydrogen service is currently of great importance. However, pipelines require frequent maintenance and repair work. In some cases, it is necessary to carry out welding work on pipelines while they are under pressure, e.g., the well-known tapping of NG grids. This in-service welding brings additional challenges for hydrogen operations in terms of additional hydrogen absorption during welding and material compatibility. The challenge can be roughly divided into two parts: (1) the possible austenitization of the inner piping material exposed to hydrogen, which can lead to additional hydrogen absorption, and (2) the welding itself causes an increased temperature range. Both lead to a significantly increased hydrogen solubility in the respective materials compared to room temperature. In that connection, the knowledge on hot tapping on hydrogen pipelines is rare so far due to the missing service experiences. Fundamental experimental investigations are required to investigate the possible transferability of the state-of-the-art concepts from NG to hydrogen pipeline grids. This is necessary to ensure that no critical material degradation occurs due to the potentially increased hydrogen uptake. For this reason, the paper introduces the state of the art in pipeline hot tapping, encompassing current research projects and their individual solution strategies for the problems that may arise for future hydrogen service. Methods of material testing, their limitations, and possible solutions will be presented and discussed.
KW - In-service
KW - Hydrogen
KW - Repair welding
KW - Pipeline
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638944
DO - https://doi.org/10.1007/s40194-025-02127-x
SN - 0043-2288
SP - 1
EP - 24
PB - Springer Science and Business Media LLC
AN - OPUS4-63894
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kern, Simon
A1 - Liehr, Sascha
A1 - Wander, Lukas
A1 - Bornemann-Pfeiffer, Martin
A1 - Müller, S.
A1 - Maiwald, Michael
A1 - Kowarik, Stefan
T1 - Artificial neural networks for quantitative online NMR spectroscopy
N2 - Industry 4.0 is all about interconnectivity, sensor-enhanced process control, and data-driven systems. Process analytical technology (PAT) such as online nuclear magnetic resonance (NMR) spectroscopy is gaining in importance, as it increasingly contributes to automation and digitalization in production. In many cases up to now, however, a classical evaluation of process data and their transformation into knowledge is not possible or not economical due to the insufficiently large datasets available. When developing an automated method applicable in process control, sometimes only the basic data of a limited number of batch tests from typical product and process development campaigns are available. However, these datasets are not large enough for training machine-supported procedures. In this work, to overcome this limitation, a new procedure was developed, which allows physically motivated multiplication of the available reference data in order to obtain a sufficiently large dataset for training machine learning algorithms. The underlying example chemical synthesis was measured and analyzed with both application-relevant low-field NMR and high-field NMR spectroscopy as reference method. Artificial neural networks (ANNs) have the potential to infer valuable process information already from relatively limited input data. However, in order to predict the concentration at complex conditions (many reactants and wide concentration ranges), larger ANNs and, therefore, a larger Training dataset are required. We demonstrate that a moderately complex problem with four reactants can be addressed using ANNs in combination with the presented PAT method (low-field NMR) and with the proposed approach to generate meaningful training data.
KW - Online NMR spectroscopy
KW - Real-time process monitoring
KW - Artificial neural networks
KW - Automation
KW - Process industry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507508
DO - https://doi.org/10.1007/s00216-020-02687-5
SN - 1618-2642
VL - 412
IS - 18
SP - 4447
EP - 4459
PB - Springer
CY - Berlin
AN - OPUS4-50750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Chi-Long
A1 - Seeger, Stefan
T1 - Measurement of sub-4 nm particle emission from FFF-3D printing with the TSI Nano Enhancer and the Airmodus Particle Size Magnifier
N2 - The emission of ultrafine particles from small desktop Fused Filament Fabrication (FFF) 3D printers has been frequently investigated in the past years. However, the vast majority of FFF emission and exposure studies have not considered the possible occurrence of particles below the typical detection limit of Condensation Particle Counters and could have systematically underestimated the total particle emission as well as the related exposure risks. Therefore, we comparatively measured particle number concentrations and size distributions of sub-4 nm particles with two commercially available diethylene glycol-based instruments – the TSI 3757 Nano Enhancer and the Airmodus A10 Particle Size Magnifier. Both instruments were evaluated for their suitability of measuring FFF-3D printing emissions in the sub-4 nm size range while operated as a particle counter or as a particle size spectrometer. For particle counting, both instruments match best when the Airmodus system was adjusted to a cut-off of 1.5 nm. For size spectroscopy, both instruments show limitations due to either the fast dynamics or rather low levels of particle emissions from FFF-3D printing in this range. The effects are discussed in detail in this article. The findings could be used to implement sub-4 nm particle measurement in future emission or exposure studies, but also for the development of standard test protocols for FFF-3D printing emissions.
KW - Air pollution
KW - Ultrafine particles
KW - Sub-4nm particles
KW - FFF-3D printing
KW - Emission testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595952
DO - https://doi.org/10.1080/02786826.2024.2320430
SN - 0278-6826
VL - 58
IS - 6
SP - 644
EP - 656
PB - Taylor & Francis
CY - London
AN - OPUS4-59595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, Chi-Long
A1 - Seeger, Stefan
A1 - Röllig, Mathias
T1 - Improving the comparability of FFF-3D printing emission data by adjustment of the set extruder temperature
N2 - Fused filament fabrication (FFF) is a material extrusion-based technique often used in desktop 3D printers. Polymeric filaments are melted and are extruded through a heated nozzle to form a 3D object in layers. The extruder temperature is therefore a key parameter for a successful print job but also one of the main emission driving factors as harmful pollutants (e.g., ultrafine particles) are formed by thermal polymer degradation. The awareness of potential health risks has increased the number of emission studies in the past years. However, studies usually refer their calculated emission data to the printer set extruder temperature for comparison purposes. In this study, we used a thermocouple and an infrared camera to measure the actual extruder temperature and found significant temperature deviations to the displayed set temperature among printer models. Our result shows that printing the same filament feedstocks with three different printer models and with identical printer set temperature resulted in a variation in particle emission of around two orders of magnitude. A temperature adjustment has reduced the variation to approx. one order of magnitude. Thus, it is necessary to refer the measured emission data to the actual extruder temperature as it poses a more accurate comparison parameter for evaluation of the indoor air quality in user scenarios or for health risk assessments.
KW - Ultrafine particles
KW - Infrared thermography
KW - Thermocouple
KW - Indoor air quality
KW - FFF-3D printer
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572842
DO - https://doi.org/10.1016/j.aeaoa.2023.100217
VL - 18
SP - 100217
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-57284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Sommer, Konstantin
A1 - Knobloch, Tim
A1 - Altenburg, Simon
A1 - Recknagel, Sebastian
A1 - Bettge, Dirk
A1 - Hilgenberg, Kai
T1 - Process Induced Preheating in Laser Powder Bed Fusion Monitored by Thermography and Its Influence on the Microstructure of 316L Stainless Steel Parts
N2 - Undetected and undesired microstructural variations in components produced by laser powder bed fusion are a major challenge, especially for safety-critical components. In this study, an in-depth analysis of the microstructural features of 316L specimens produced by laser powder bed fusion at different levels of volumetric energy density and different levels of inter layer time is reported. The study has been conducted on specimens with an application relevant build height
(>100 mm). Furthermore, the evolution of the intrinsic preheating temperature during the build-up of specimens was monitored using a thermographic in-situ monitoring set-up. By applying recently determined emissivity values of 316L powder layers, real temperatures could be quantified. Heat accumulation led to preheating temperatures of up to about 600 °C. Significant differences in the preheating temperatures were discussed with respect to the individual process parameter combinations, including the build height. A strong effect of the inter layer time on the heat accumulation was observed. A shorter inter layer time resulted in an increase of the preheating temperature by more than a factor of 2 in the upper part of the specimens compared to longer inter layer times. This, in turn, resulted in heterogeneity of the microstructure and differences in material properties within individual specimens. The resulting differences in the microstructure were analyzed using electron back scatter diffraction and scanning electron microscopy. Results from chemical analysis as well as electron back scatter diffraction measurements indicated stable conditions in terms of chemical alloy composition and austenite phase content for the used set of parameter combinations. However, an increase of the average grain size by more than a factor of 2.5 could be revealed within individual specimens. Additionally, differences in feature size of the solidification cellular substructure were examined and a trend of increasing cell sizes was observed. This trend was attributed to differences in solidification rate and thermal gradients induced by differences in scanning velocity and preheating temperature. A change of the thermal history due to intrinsic preheating could be identified as the main cause of this heterogeneity. It was induced by critical combinations of the energy input and differences in heat transfer conditions by variations of the inter layer time. The microstructural variations were directly correlated to differences in hardness.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - In-situ process monitoring
KW - Thermography
KW - Heat accumulation
KW - Inter layer time
KW - Cellular substructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529240
DO - https://doi.org/10.3390/met11071063
VL - 11
IS - 7
SP - 1063
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-52924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tuma, Dirk
A1 - Moreau, A.
A1 - Polishuk, I.
A1 - Segovia, J. J.
A1 - Vega-Maza, D.
A1 - Martín, M. C.
T1 - Measurements and predictions of densities and viscosities in CO2 + hydrocarbon mixtures at high pressures and temperatures: CO2 + n-pentane and CO2 + n-hexane blends
N2 - This work reports new experimental data on densities and viscosities of (CO2 + n-pentane) and (CO2 + n-hexane) mixtures at high pressures and temperatures. The densities were measured by a vibrating-tube densimeter with an expanded uncertainty (k = 2) smaller than 1.8 kg/m3 at six isotherms (from 273.15 K to 373.15 K), twelve pressures starting at 5 MPa up to 100 MPa, and at six CO2 molar compositions (from 0 to 0.6). The viscosities were measured by a vibrating-wire viscometer with the corresponding relative expanded uncertainty (k = 2) smaller than 0.016 at five isotherms (from 273.15 K to 373.15 K), twelve pressures (from 5 MPa up to 100 MPa), and at two CO2 molar compositions (0.1 and 0.3). The densities were fitted by the semiempirical Tammann-Tait equation for density data and the Vogel-Fulcher-Tammann (VFT) equation for viscosity data, respectively. The Groupe Européen de Recherches Gazières (GERG-2008) equation of state was also applied for modelling the densities. Over-all robustness and reliability of the Perturbed-Chain Statistical Association Fluid Theory (PC-SAFT) and its critical point-based modification (CP-PC-SAFT) were examined. Accuracies of the Modified Yarranton-Satyro (MYS) coupled with CP-PC-SAFT and the NIST Reference Fluid Thermodynamic and Transport Properties Database (REFPROP 10) in predicting the viscosities were evaluated.
KW - CO2 + n-alkanes
KW - thermophysical properties
KW - Perturbed-Chain Statistical Association Fluid Theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555728
DO - https://doi.org/10.1016/j.molliq.2022.119518
SN - 0167-7322
VL - 360
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kimani, Martha Wamaitha
A1 - Kislenko, Evgeniia
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Fluorescent molecularly imprinted polymer particles for glyphosate detection using phase transfer agents
N2 - In this work, molecular imprinting was combined with direct fluorescence detection of the pesticide Glyphosate (GPS). Firstly, the solubility of highly polar GPS in organic solvents was improved by using lipophilic tetrabutylammonium (TBA+) and tetrahexylammonium (THA+) counterions. Secondly, to achieve fluorescence detection, a fluorescent crosslinker containing urea-binding motifs was used as a probe for GPS-TBA and GPS-THA salts in chloroform, generating stable complexes through hydrogen bond formation. The GPS/fluorescent dye complexes were imprinted into 2–3 nm fluorescent molecularly imprinted polymer (MIP) shells on the surface of sub-micron silica particles using chloroform as porogen. Thus, the MIP binding behavior could be easily evaluated by fluorescence titrations in suspension to monitor the spectral changes upon addition of the GPS analytes. While MIPs prepared with GPS-TBA and GPS-THA both displayed satisfactory imprinting following titration with the corresponding analytes in chloroform, GPS-THA MIPs displayed better selectivity against competing molecules. Moreover, the THA+ counterion was found to be a more powerful phase transfer agent than TBA+ in a biphasic assay, enabling the direct fluorescence detection and quantification of GPS in water. A limit of detection of 1.45 μM and a linear range of 5–55 μM were obtained, which match well with WHO guidelines for the acceptable daily intake of GPS in water (5.32 μM).
KW - Glyphosate
KW - Molecular imprinting
KW - Core-shell particles
KW - Fluorescent sensors
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555281
DO - https://doi.org/10.1038/s41598-022-16825-9
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 15
PB - Macmillan Publishers Limited
CY - London
AN - OPUS4-55528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, M.
A1 - Diercks, P.
A1 - Manzoni, Anna Maria
A1 - Čížek, J.
A1 - Ramamurty, U.
A1 - Banhart, J.
T1 - Positron annihilation investigation of thermal cycling induced martensitic transformation in NiTi shape memory alloy
N2 - Thermal cycling of a Ni-excess NiTi alloy was conducted between 50 °C and liquid nitrogen temperature to induce martensitic transformations and to reverse them after. The starting point was an annealed and slowly cooled state, the end point a sample thermally cycled 1500 times. Positron annihilation lifetime spectra and Coincidence Doppler Broadening profiles were obtained in various states and at various tem- peratures. It was found that the initial state was low in defects with positron lifetimes close to that of bulk NiTi. Cycling lead to a continuous build-up of a defect structure up to 20 0 −50 0 cycles after which saturation was reached. Two types of defects created during cycling were identified, namely pure dislo- cations and vacancies attached to dislocations.
KW - Shape memory alloy
KW - Thermal Cycling
KW - Defects
KW - Positron annihilation spectroscopy
KW - Austenite-to-martensite phase transformation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533641
DO - https://doi.org/10.1016/j.actamat.2021.117298
VL - 220
SP - 117298
PB - Elsevier Ltd.
AN - OPUS4-53364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blumrich, A.
A1 - Vogler, G.
A1 - Dresen, S.
A1 - Diop, S. B.
A1 - Jaeger, Carsten
A1 - Leberer, S.
A1 - Grune, J.
A1 - Wirth, E. K.
A1 - Hoeft, B.
A1 - Renko, K.
A1 - Foryst-Ludwig, A.
A1 - Spranger, J.
A1 - Sigrist, S.
A1 - Bodmer, R.
A1 - Kintscher, U.
T1 - Fat-body brummer lipase determines survival and cardiac function during starvation in Drosophila melanogaster
N2 - The cross talk between adipose tissue and the heart has an increasing importance for cardiac function under physiological and pathological conditions. This study characterizes the role of fat body lipolysis for cardiac function in Drosophila melanogaster.
Perturbation of the function of the key lipolytic enzyme, brummer (bmm), an ortholog of themammalian ATGL (adipose triglyceride lipase) exclusively in the fly’s fat body, protected the heart against starvation-induced dysfunction.
We further provide evidence that this protection is caused by the preservation of glycerolipid stores, resulting in a starvation-resistant maintenance of energy supply and adequate cardiac ATP synthesis. Finally, we suggest that alterations of lipolysis are tightly coupled to lipogenic processes, participating in the preservation of Lipid energy substrates during starvation. Thus, we identified the inhibition of adipose tissue lipolysis and subsequent energy preservation as a protective mechanism against cardiac dysfunction during catabolic stress.
KW - High-resolution mass spectrometry
KW - Nontarget analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528756
DO - https://doi.org/10.1016/j.isci.2021.102288
VL - 24
IS - 4
SP - 102288
AN - OPUS4-52875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jaeger, Carsten
A1 - Ritter, D.
A1 - Goeritzer, M.
A1 - Thiele, A.
A1 - Blumrich, A.
A1 - Beyhoff, N.
A1 - Luettges, K.
A1 - Smeir, E.
A1 - Kasch, J.
A1 - Grune, J.
A1 - Müller, O.
A1 - Klopfleisch, R.
A1 - Foryst-Ludwig, A.
A1 - Kintscher, U.
T1 - Liver X Receptor Agonist AZ876 Induces Beneficial Endogenous Cardiac Lipid Reprogramming and Protects Against Isoproterenol-Induced Cardiac Damage
N2 - Background - It is known that dietary intake of polyunsaturated fatty acids may improve cardiac function. However, relatively high daily doses are required to achieve sufficient cardiac concentrations of beneficial omega‐3 fatty acids. The liver X receptor (LXR) is a nuclear hormone receptor and a crucial regulator of lipid homeostasis in mammals. LXR activation has been shown to endogenously reprogram cellular lipid profiles toward increased polyunsaturated fatty acids levels. Here we studied whether LXR lipid reprogramming occurs in cardiac tissue and exerts cardioprotective actions.
Methods and Results - Male 129SV mice were treated with the LXR agonist AZ876 (20 µmol/kg per day) for 11 days. From day 6, the mice were injected with the nonselective β‐agonist isoproterenol for 4 consecutive days to induce diastolic dysfunction and subendocardial fibrosis while maintaining systolic function. Treatment with isoproterenol led to a marked impairment of global longitudinal strain and the E/e' ratio of transmitral flow to mitral annular velocity, which were both significantly improved by the LXR agonist. Histological examination showed a significant reduction in isoproterenol‐induced subendocardial fibrosis by AZ876. Analysis of the cardiac lipid composition by liquid chromatography‐high resolution mass spectrometry revealed a significant increase in cardiac polyunsaturated fatty acids levels and a significant reduction in saturated fatty acids by AZ876.
Conclusions - The present study provides evidence that the LXR agonist AZ876 prevents subendocardial damage, improves global longitudinal strain and E/e' in a mouse model of isoproterenol‐induced cardiac damage, accompanied by an upregulation of cardiac polyunsaturated fatty acids levels. Cardiac LXR activation and beneficial endogenous cardiac lipid reprogramming may provide a new therapeutic strategy in cardiac disease with diastolic dysfunction.
KW - Heart failure
KW - Lipids
KW - Liver X receptor
KW - Diastolic dysfunction
KW - Nuclear receptor
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529352
DO - https://doi.org/10.1161/JAHA.120.019473
VL - 10
IS - 14
SP - e019473
AN - OPUS4-52935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Langenhan, Jennifer
A1 - Jaeger, Carsten
A1 - Baum, K.
A1 - Simon, M.
A1 - Lisec, Jan
T1 - A Flexible Tool to Correct Superimposed Mass Isotopologue Distributions in GC‐APCI‐MS Flux Experiments
N2 - The investigation of metabolic fluxes and metabolite distributions within cells by means of tracer molecules is a valuable tool to unravel the complexity of biological systems. Technological advances in mass spectrometry (MS) technology such as atmospheric pressure chemical ionization (APCI) coupled with high resolution (HR), not only allows for highly sensitive analyses but also broadens the usefulness of tracer‐based experiments, as interesting signals can be annotated de novo when not yet present in a compound library. However, several effects in the APCI ion source, i.e., fragmentation and rearrangement, lead to superimposed mass isotopologue distributions (MID) within the mass spectra, which need to be corrected during data evaluation as they will impair enrichment calculation otherwise. Here, we present and evaluate a novel software tool to automatically perform such corrections. We discuss the different effects, explain the implemented
algorithm, and show its application on several experimental datasets. This adjustable tool is available as an R package from CRAN.
KW - Mass Spectrometry
KW - Isotopologue Distribution
KW - Metabolic Flux
KW - R package
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547318
DO - https://doi.org/10.3390/metabo12050408
VL - 12
IS - 5
SP - 1
EP - 10
PB - MDPI
AN - OPUS4-54731
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kimani, Martha Wamaitha
A1 - Pérez-Padilla, Victor
A1 - Valderrey, Virginia
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Red-Emitting Polymerizable Guanidinium Dyes as Fluorescent Probes in Molecularly Imprinted Polymers for Glyphosate Detection
N2 - The development of methodologies to sense glyphosate has gained momentum due to its toxicological and ecotoxicological effects. In this work, a red-emitting and polymerizable guanidinium benzoxadiazole probe was developed for the fluorescence detection of glyphosate. The interaction of the fluorescent probe and the tetrabutylammonium salt of glyphosate was studied via UV/vis absorption and fluorescence spectroscopy in chloroform and acetonitrile. The selective recognition of glyphosate was achieved by preparing molecularly imprinted polymers, able to discriminate against other common herbicides such as 2,4-dichlorophenoxyacetic acid (2,4-D) and 3,6-dichloro-2-methoxybenzoic acid (dicamba), as thin layers on submicron silica particles. The limits of detection of 4.8 µM and 0.6 µM were obtained for the sensing of glyphosate in chloroform and acetonitrile, respectively. The reported system shows promise for future application in the sensing of glyphosate through further optimization of the dye and the implementation of a biphasic assay with water/organic solvent mixtures for sensing in aqueous environmental samples.
KW - Glyphosate
KW - Guanidinium receptors
KW - Fluorescent probes
KW - Molecularly imprinted polymers
KW - Core-shell particles
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544441
DO - https://doi.org/10.3390/chemosensors10030099
SN - 2227-9040
VL - 10
IS - 3
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-54444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jaeger, Carsten
A1 - Lisec, Jan
T1 - Towards Unbiased Evaluation of Ionization Performance in LC-HRMS Metabolomics Method Development
N2 - As metabolomics increasingly finds its way from basic science into applied and regulatory environments, analytical demands on nontargeted mass spectrometric detection methods continue to rise. In addition to improved chemical comprehensiveness, current developments aim at enhanced robustness and repeatability to allow long-term, inter-study, and meta-analyses. Comprehensive metabolomics relies on electrospray ionization (ESI) as the most versatile ionization technique, and recent liquid chromatography-high resolution mass spectrometry (LC-HRMS) instrumentation continues to overcome technical limitations that have hindered the adoption of ESI for applications in the past. Still, developing and standardizing nontargeted ESI methods and instrumental setups remains costly in terms of time and required chemicals, as large panels of metabolite standards are needed to reflect biochemical diversity. In this paper, we investigated in how far a nontargeted pilot experiment, consisting only of a few measurements of a test sample dilution series and comprehensive statistical analysis, can replace conventional targeted evaluation procedures. To examine this potential, two instrumental ESI ion source setups were compared, reflecting a common scenario in practical method development. Two types of feature evaluations were performed, (a) summary statistics solely involving feature intensity values, and (b) analyses additionally including chemical interpretation.
Results were compared in detail to a targeted evaluation of a large metabolite standard panel. We reflect on the advantages and shortcomings of both strategies in the context of current harmonization initiatives in the metabolomics field.
KW - Mass Spectrometry
KW - Non-targeted analysis
KW - Method development
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548065
DO - https://doi.org/10.3390/metabo12050426
VL - 12
IS - 5
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-54806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valderrey, Virginia
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Thiourea- and Amino-Substituted Benzoxadiazole Dyes with Large Stokes Shifts as Red-Emitting Probe Monomers for Imprinted Polymer Layers Targeting Carboxylate-Containing Antibiotics
N2 - Bifunctional fluorescent molecular oxoanion probes based on the benzoxadiazole (BD) chromophore are described which integrate a thiourea binding motif and a polymerizable 2-aminoethyl methacrylate unit in the 4,7-positions of the BD core. Concerted charge transfer in this electron donor-acceptor-donor architecture endows the dyes with strongly Stokes shifted (up to >250 nm) absorption and fluorescence. Binding of electron-rich carboxylate guests at the thiourea receptor leads to further analyte-induced red-shifts of the emission, shifting the fluorescence maximum of the complexes to ≥700 nm. Association constants for acetate are ranging from 1–5×105 M−1 in acetonitrile. Integration of one of the fluorescent probes through its polymerizable moiety into molecularly imprinted polymers (MIPs) grafted from the surface of submicron silica cores yielded fluorescent MIP-coated particle probes for the selective detection of antibiotics containing aliphatic carboxylate groups such as enoxacin (ENOX) at micromolar concentrations in highly polar solvents like acetonitrile.
KW - Molecular imprinting
KW - Anion recognition
KW - Antibiotics
KW - Benzoxadiazole dyes
KW - Charge transfer
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545027
DO - https://doi.org/10.1002/chem.202104525
SN - 1521-3765
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-54502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sommer, Konstantin
A1 - Agudo Jácome, Leonardo
A1 - Hesse, René
A1 - Bettge, Dirk
T1 - Revealing the nature of melt pool boundaries in additively manufactured stainless steel by nano-sized modulation
N2 - In the current study, the 3D nature of the melt pool boundaries (MPBs) in a 316 L austenitic steel additively manufactured by laser-based powder bed fusion (L-PBF) is investigated. The change of the cell growth direction and its relationship to the MPBs is investigated by transmission electron microscopy. A hitherto unreported modulated substructure with a periodicity of 21 nm is further discovered within the cell cores of the cellular substructure, which results from a partial transformation of the austenite, which is induced by a Ga+ focused ion beam. While the cell cores show the modulated substructure, cell boundaries do not. The diffraction pattern of the modulated substructure is exploited to show a thickness ≥200 nm for the MPB. At MPBs, the cell walls are suppressed, leading to continuously connecting cell cores across the MPB. This continuous MPB is described either as overlapping regions of cells of different growing directions when a new melt pool solidifies or as a narrow planar growth preceding the new melt pool.
KW - Additive manufacturing
KW - Austenitic steel 316L
KW - Melt pool boundary
KW - Microstructural characterization
KW - Transmission electron microscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547295
DO - https://doi.org/10.1002/adem.202101699
SN - 1527-2648
VL - 24
IS - 6
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beyer, S.
A1 - Kimani, Martha Wamaitha
A1 - Zhang, Y.
A1 - Verhassel, A.
A1 - Sternbæk, L.
A1 - Wang, T.
A1 - Persson, J. L.
A1 - Härkönen, P.
A1 - Johansson, E.
A1 - Caraballo, R.
A1 - Elofsson, M.
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Ohlsson, L.
A1 - El-Schich, Z.
A1 - Gjörloff Wingren, A.
A1 - Stollenwerk, M. M.
T1 - Fluorescent Molecularly Imprinted Polymer Layers against Sialic Acid on Silica-coated Polystyrene Cores - Assessment of the Binding Behavior to Cancer Cells
N2 - Sialic acid (SA) is a monosaccharide usually linked to the terminus of glycan chains on the cell surface. It plays a crucial role in many biological processes, and hypersialylation is a common feature in cancer. Lectins are widely used to analyze the cell surface expression of SA.
However, these protein molecules are usually expensive and easily denatured, which calls for the development of alternative glycan-specific receptors and cell imaging technologies. In this study, SA-imprinted fluorescent core-shell molecularly imprinted polymer particles (SA-MIPs) were employed to recognize SA on the cell surface of cancer cell lines. The SA-MIPs improved suspensibility and scattering properties compared with previously used core-shell SA-MIPs. Although SA-imprinting was performed using SA without preference for the alpha-2,3- and alpha-2,6-SA forms, we screened the cancer cell lines analyzed using the lectins Maackia Amurensis Lectin I (MAL I, alpha-2,3-SA) and Sambucus Nigra Lectin (SNA, alpha-2,6-SA). Our results show that the selected cancer cell lines in this study presented a varied binding behavior with the SA-MIPs. The binding pattern of the lectins was also demonstrated. Moreover, two different pentavalent SA conjugates were used to inhibit the binding of the SA-MIPs to breast, skin, and lung cancer cell lines, demonstrating the specificity of the SA-MIPs in both flow cytometry and confocal fluorescence microscopy. We concluded that the synthesized SA-MIPs might be a powerful future tool in the diagnostic analysis of various cancer cells.
KW - Cancer
KW - Imprinting
KW - Molecularly imprinted polymers
KW - SA conjugates
KW - Sialic acid
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546625
DO - https://doi.org/110.3390/cancers14081875
SN - 2072-6694
VL - 14
IS - 8
PB - MDPI
CY - Basel
AN - OPUS4-54662
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Inui, H.
A1 - Kishida, K.
A1 - Li, L.
A1 - Manzoni, Anna Maria
A1 - Haas, S.
A1 - Glatzel, U.
T1 - Uniaxial mechanical properties of face‑centered cubic singleand multiphase high‑entropy alloys
N2 - Since the high entropy concept was proposed at the beginning of the millennium, the research focus of this alloy family has been wide ranging. The initial search for single-phase alloys has expanded with the aim of improving mechanical properties. This can be achieved by several strengthening mechanisms such as solid-solution hardening, hot and cold working and precipitation hardening. Both single- and multiphase high- and medium-entropy alloys can be optimized for mechanical strength via several processing routes, as is the case for conventional alloys with only one base element, such as steels or Ni-based superalloys.
KW - High entropy alloy
KW - Compositionally complex alloys
KW - Tensile properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543955
DO - https://doi.org/10.1557/s43577-022-00280-y
VL - 47
IS - 2
SP - 168
EP - 174
PB - Springer
AN - OPUS4-54395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sternbaek, L.
A1 - Kimani, Martha Wamaitha
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Janicke, B.
A1 - Alm, K.
A1 - Gjörloff-Wingren, A.
A1 - Eriksson, H.
T1 - Molecularly Imprinted Polymers Exhibit Low Cytotoxic and Inflammatory Properties in Macrophages In Vitro
N2 - Molecularly imprinted polymers (MIPs) against sialic acid (SA) have been developed as a detection tool to target cancer cells. Before proceeding to in vivo studies, a better knowledge of the overall effects of MIPs on the innate immune system is needed. The aim of this study thus was to exemplarily assess whether SA-MIPs lead to inflammatory and/or cytotoxic responses when administered to phagocytosing cells in the innate immune system. The response of monocytic/macrophage cell lines to two different reference particles, Alhydrogel and PLGA, was compared to their response to SA-MIPs. In vitro culture showed a cellular association of SA-MIPs and Alhydrogel, as analyzed by flow cytometry. The reference particle Alhydrogel induced secretion of IL-1b from the monocytic cell line THP-1, whereas almost no secretion was provoked for SA-MIPs. A reduced number of both THP-1 and RAW 264.7 cells were observed after incubation with SA-MIPs and this was not caused by cytotoxicity. Digital holographic cytometry showed that SA-MIP treatment affected cell division, with
much fewer cells dividing. Thus, the reduced number of cells after SA-MIP treatment was not linked to SA-MIPs cytotoxicity. In conclusion, SA-MIPs have a low degree of inflammatory properties, are not cytotoxic, and can be applicable for future in vivo studies.
KW - Molecularly imprinted polymers
KW - Digital holographic cytometry
KW - Cytotoxicity
KW - Proinflammatory cytokines
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552250
DO - https://doi.org/10.3390/app12126091
SN - 2076-3417
VL - 12
IS - 12
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55225
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Wan, Wei
A1 - Rurack, Knut
T1 - Toward Label-Free Optical Multiplexing of Analytes in Indicator Release Lateral Flow Assays via Detection Zones Containing Tailored Capture Materials
N2 - The use of macromolecules and materials immobilized in the detection zone of test strips for indicator capture and focusing in label-free lateral flow assays (LFAs) is described, with emphasis on its future use in low number multiplexing. Several materials such as polyelectrolytes, functionalized mesoporous silica micro- and nanoparticles, chemically modified cellulose or glass fibre (GF) membranes and molecularly imprinted polymer gels coated onto membranes were studied in model assays, before the most promising materials were combined with antibody-gated indicator delivering (gAID) sensor materials. Cellulose, nitrocellulose and GF membranes were used as supports and highly fluorescent dyes of different charge states as model indicators. Combination of the best performing capture materials with gAID systems made it possible to distinctly increase the sensitivity and reduce the measurement uncertainty in the LFA testing of pentaerythritol tetranitrate (PETN) in aqueous samples. In addition, dual-plexing of PETN and 2,4,6-trinitrotoluene (TNT) was realized on a single test strip containing two dedicated capture zones.
KW - Rapid tests
KW - Vor-Ort-Analytik
KW - Multiplexing
KW - Teststreifen
KW - Molecularly imprinted polymers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557873
DO - https://doi.org/10.1002/anse.202100062
VL - 2
IS - 4
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munir, R.
A1 - Noureen, N.
A1 - Bashir, M.
A1 - Shoaib, N.
A1 - Ashraf, A.
A1 - Lisec, Jan
A1 - Zaidi, N.
T1 - Cancer Awareness Measure (CAM) and Cancer Awareness Measure MYthical Causes Scale (CAM‑MY) scores in Pakistani population
N2 - Lifestyle modifications could prevent almost one‑third to one‑half of all cancer cases. The awareness of cancer risk factors could motivate people to make such changes in their behaviors and lifestyles. This work aims to investigate the cancer awareness level in the Pakistani population. Telephone interviews of 657 individuals in Pakistan were carried out using the Cancer Awareness Measure (CAM) and Cancer Awareness Measure–MYthical Causes Scale (CAM‑MY). We observed that participants scored significantly better on the CAM scale than the CAM‑MY scale, and CAM scores were negatively associated with CAM‑MY scores. Years of formal education or a biology major at undergraduate or graduate level did not affect our population’s cancer awareness levels. Age displayed a weak but statistically significant negative association with CAM scores. Most participants failed to identify modifiable cancer risk factors, e.g., low physical activity. Efforts should be made to improve awareness of modifiable risk factors. We observed that brief training sessions could markedly improve people’s understanding of cancer risk factors and myths.
KW - Cancer
KW - Cancer awareness measure
KW - Cancer risk
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548960
DO - https://doi.org/10.1038/s41598-022-13012-8
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 10
PB - Nature Publishing Group
CY - London
AN - OPUS4-54896
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tukhmetova, Dariya
A1 - Lisec, Jan
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Data processing made easy: standalone tool for automated calculation of isotope ratio from transient signals – IsoCor
N2 - Despite numerous advantages offered by hyphenation of chromatography and electrokinetic separation methods with multicollector (MC) ICP-MS for isotope analysis, the main limitation of such systems is the decrease in precision and increase in uncertainty due to generation of short transient signals. To minimize this limitation, most authors compare several isotope ratio calculation methods and establish a multi-step data processing routine based on the precision and accuracy of the methods. However, to the best of our knowledge, there is no universal data processing tool available that incorporates all important steps of the treatment of the transient signals. Thus, we introduce a data processing application (App) IsoCor that facilitates automatic calculation of isotope ratios from transient signals and eases selection of the most suitable method. The IsoCor App performs baseline subtraction, peak detection, mass bias correction, isotope ratio calculation and delta calculation. The feasibility and reliability of the App was proven by reproducing the results from isotope analysis of three elements (neodymium, mercury and sulfur) measured on-line via hyphenated systems. The IsoCor App provides trackability of the results to ensure quality control of the analysis.
KW - Isotope ratio
KW - Transient signal
KW - MC-ICP-MS
KW - Data processing
KW - App
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559068
DO - https://doi.org/10.1039/D2JA00208F
VL - 37
IS - 11
SP - 2401
EP - 2409
PB - Royal Society of Chemistry
AN - OPUS4-55906
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Orf, I.
A1 - Tenenboim, H.
A1 - Omranian, N.
A1 - Nikoloski, Z.
A1 - Fernie, A. R.
A1 - Lisec, Jan
A1 - Brotman, Y.
A1 - Bromke, M. A.
T1 - Transcriptomic and Metabolomic Analysis of a Pseudomonas-Resistant versus a Susceptible Arabidopsis Accession
N2 - Accessions of one plant species may show significantly different levels of susceptibility to stresses. The Arabidopsis thaliana accessions Col-0 and C24 differ significantly in their resistance to the pathogen Pseudomonas syringae pv. tomato (Pst). To help unravel the underlying mechanisms contributing to this naturally occurring variance in resistance to Pst, we analyzed changes in transcripts and compounds from primary and secondary metabolism of Col-0 and C24 at different time points after infection with Pst. Our results show that the differences in the resistance of Col-0 and C24 mainly involve mechanisms of salicylic-acid-dependent systemic acquired resistance, while responses of jasmonic-acid-dependent mechanisms are shared between the two accessions. In addition, arginine metabolism and differential activity of the biosynthesis pathways of aliphatic glucosinolates and indole glucosinolates may also contribute to the resistance. Thus, this study highlights the difference in the defense response strategies utilized by different genotypes.
KW - Mass Spectrometry
KW - Arabidopsis
KW - Resistance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559549
DO - https://doi.org/10.3390/ijms232012087
VL - 23
IS - 20
SP - 1
EP - 27
PB - MDPI
AN - OPUS4-55954
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jiang, Shan
A1 - Wang, T.
A1 - Behren, S.
A1 - Westerlind, U.
A1 - Gawlitza, Kornelia
A1 - Persson, J. L.
A1 - Rurack, Knut
T1 - Sialyl-Tn Antigen-Imprinted Dual Fluorescent Core–Shell Nanoparticles for Ratiometric Sialyl-Tn Antigen Detection and Dual-Color Labeling of Cancer Cells
N2 - Sialyl-Tn (STn or sialyl-Thomsen-nouveau) is a carbohydrate antigen expressed by more than 80% of human carcinomas. We here report a strategy for ratiometric STn detection and dual-color cancer cell labeling, particularly, by molecularly imprinted polymers (MIPs). Imprinting was based on spectroscopic studies of a urea-containing green-fluorescent monomer 1 and STn-Thr-Na (sodium salt of Neu5Acα2-6GalNAcα-O-Thr). A few-nanometer-thin green-fluorescent polymer shell, in which STn-Thr-Na was imprinted with 1, other comonomers, and a cross-linker, was synthesized from the surface of red-emissive carbon nanodot (R-CND)-doped silica nanoparticles, resulting in dual fluorescent STn-MIPs. Dual-color labeling of cancer cells was achieved since both red and green emissions were detected in two separate channels of the microscope and an improved accuracy was obtained in comparison with single-signal MIPs. The flow cytometric cell analysis showed that the binding of STn-MIPs was significantly higher (p < 0.001) than that of non-imprinted polymer (NIP) control particles within the same cell line, allowing to distinguish populations. Based on the modularity of the luminescent core–fluorescent MIP shell architecture, the concept can be transferred in a straightforward manner to other target analytes.
KW - Cancer
KW - Core−shell particles
KW - Dual-color labeling glycan
KW - Molecular imprinting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563106
DO - https://doi.org/10.1021/acsanm.2c03252
SP - 1
EP - 14
PB - ACS Publications
AN - OPUS4-56310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kubheka, G.
A1 - Climent, Estela
A1 - Tobias, Charlie
A1 - Rurack, Knut
A1 - Mack, J.
A1 - Nyokong, T.
T1 - Multiplexed Detection of Human Papillomavirus Based on AzaBODIPY-Doped Silica-Coated Polystyrene Microparticles
N2 - Human papillomavirus (HPV) DNA detection can enable the early diagnosis of high-risk HPV types responsible for cervical cancer. HPV detection is also essential for investigating the clinical behavior and epidemiology of particular HPV types, characterization of study populations in HPV vaccination trials and monitoring the efficacy of HPV vaccines. In this study, two azaBODIPY dyes (1 and 2) were used as references and were doped into polystyrene particles (PS40), while a short HPV DNA single strand was used as a target molecule and was covalently bound to the silica shell. These particles were employed as optical probes in 1:1 hybridization assays, and their potential applicability as a tool for multiplex assays for the detection of different strands of HPV was evaluated using flow cytometry. A good separation in the fluorescence of the four different voncentrations prepared for each dye was observed. To perform the hybridization assays, HPV18, HPV16, HPV11 and HPV6 single strands were attached to the particles through EDC-mediated coupling. The c-DNA-1-PS40 and c-DNA-2-PS40 particles exhibited low limit of detection (LOD) and quantification (LOQ) values for HPV11, and a narrow detection range was obtained. Multiplexed assay experiments were successfully performed for both particles, and the results proved that c-DNA-1-PS40 could potentially be used as a tool for multiplexing assays and merits further in-depth study in this context.
KW - Flow cytometry
KW - BODIPY dyes
KW - Core-shell particles
KW - Multiplexed assay
KW - Human papillomavirus
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567358
DO - https://doi.org/10.3390/chemosensors11010001
SN - 2227-9040
VL - 11
IS - 1
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-56735
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Burnage, Samual
A1 - Bell, Jérémy
A1 - Wan, Wei
A1 - Kislenko, Evgeniia
A1 - Rurack, Knut
T1 - Combining a hybrid chip and tube microfluidic system with fluorescent molecularly imprinted polymer (MIP) core–shell particles for the derivatisation, extraction, and detection of peptides with N-terminating phosphorylated tyrosine
N2 - The reliable identification and quantitation of phosphorylated amino acids, peptides and proteins is one of the key challenges in contemporary bioanalytical research, an area of particular interest when attempting to diagnose and treat diseases at an early stage. We have developed a synthetic probe for targeting phosphorylated amino acids, based on core–shell submicron-sized particles consisting of a silica core, coated with a molecularly imprinted polymer (MIP) shell. The MIP layer contains a fluorescent probe crosslinker which binds selectively to phosphorylated tyrosine (pY) moieties with a significant imprinting factor (IF) and responds with a "light-up” fluorescence signal. The bead-based ratiometric detection scheme has been successfully transferred to a microfluidic chip format and its applicability to rapid assays has been exemplarily shown by discriminating a pY-terminating oligopeptide against its nonphosphorylated counterpart. Such miniaturised devices could lead to an automated pY or pY N-terminated peptide measurement system in the future. The setup combines a modular microfluidic system for amino acid derivatisation, extraction (by micropillar co-flow) and selective adsorption and detection with the fluorescent MIP core–shell particle probes. A miniaturised optical assembly for low-light fluorescence measurements was also developed, based on miniaturised opto-electronic parts and optical fibres. The emission from the MIP particles upon binding of pY or pY N-terminated peptides could be monitored in real-time.
KW - Microfluidics
KW - Molecularly imprinted polymers
KW - Phosphorylated peptides
KW - Fluorescence
KW - Core-shell particles
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569204
DO - https://doi.org/10.1039/d2lc00955b
SN - 1473-0197
VL - 23
IS - 3
SP - 466
EP - 474
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-56920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Garrido, E.
A1 - Hernández-Sigüenza, G.
A1 - Climent, Estela
A1 - Marcos, M. D.
A1 - Rurack, Knut
A1 - Gaviña, P.
A1 - Parra, M.
A1 - Sancenón, F.
A1 - Martí-Centelles, V.
A1 - Martínez-Máñez, R.
T1 - Strip-based lateral flow-type indicator displacement assay for γ-hydroxybutyric acid (GHB) detection in beverages
N2 - The use of gamma-hydroxybutyric acid (GHB) in drug-facilitated sexual assault has increased due to its availability and high solubility in aqueous solutions and alcoholic beverages, necessitating the development of rapid methods for GHB detection. In this respect, portable testing methods for use in the field, based on lateral flow assays (LFAs) and capable of detecting trace concentrations of target analytes, are particularly attractive and hold enormous potential for the detection of illicit drugs. Using this strategy, here we report a rapid, low cost, easy-to-handle strip-based LFA for GHB analysis employing a smartphone for fluorescence readout. At molecular signalling level, the ensemble is based on a Cu2+ complex with a tetradentate ligand and the fluorescent dye coumarin 343, which indicate GHB through an indicator displacement assay (IDA) in aqueous solution. When incorporated in a LFA-based strip test this system shows a detection limit as low as 0.03 μM for GHB in MES buffer solution and is able to detect GHB at concentrations of 0.1 μM in soft drinks and alcoholic beverages in only 1 min.
KW - Indicator displacement assay
KW - Gamma-hydroxybutyric acid
KW - Lateral flow assay
KW - Test strip
KW - Fluorescent dyes
KW - Smartphone readout
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564631
DO - https://doi.org/10.1016/j.snb.2022.133043
SN - 0925-4005
VL - 377
SP - 1
EP - 7
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-56463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yesilcicek, Yasemin
A1 - Haas, S.
A1 - Suárez Ocano, Patricia
A1 - Zaiser, E.
A1 - Hesse, René
A1 - Többens, D. M.
A1 - Glatzel, U.
A1 - Manzoni, Anna Maria
T1 - Controlling Lattice Misfit and Creep Rate Through the γ' Cube Shapes in the Al10Co25Cr8Fe15Ni36Ti6 Compositionally Complex Alloy with Hf and W Additions
N2 - Trace elements play an important role in the fine-tuning of complex material properties. This study focuses on the correlation of microstructure, lattice misfit and creep properties. The compositionally complex alloy Al10Co25Cr8Fe15Ni36Ti6 (in at. %) was tuned with high melting trace elements Hf and W. The microstructure consists of a γ matrix, γ' precipitates and the Heusler phase and it is accompanied by good mechanical properties for high temperature applications. The addition of 0.5 at.% Hf to the Al10Co25Cr8Fe15Ni36Ti6 alloy resulted in more sharp-edged cubic γ′ precipitates and an increase in the Heusler phase amount. The addition of 1 at.% W led to more rounded γ′ precipitates and the dissolution of the Heusler phase. The shapes of the γ' precipitates of the alloys Al9.25Co25Cr8Fe15Ni36Ti6Hf0.25W0.5 and Al9.25Co25Cr8Fe15Ni36Ti6Hf0.5W0.25, that are the alloys of interest in this paper, create a transition from the well-rounded precipitates in the alloy with 1% W containing alloy to the sharp angular particles in the alloy with 0.5% Hf. While the lattice misfit has a direct correlation to the γ' precipitates shape, the creep rate is also related to the amount of the Heusler phase. The lattice misfit increases with decreasing corner radius of the γ' precipitates. So does the creep rate, but it also increases with the amount of Heusler phase. The microstructures were investigated by SEM and TEM, the lattice misfit was calculated from the lattice parameters obtained by synchrotron radiation measurements.
KW - High entropy alloy
KW - Lattice misfit
KW - Creep
KW - Transmission electron microscopy
KW - X-ray diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565655
DO - https://doi.org/10.1007/s44210-022-00009-1
SP - 1
EP - 9
PB - Springer
AN - OPUS4-56565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munir, R.
A1 - Lisec, Jan
A1 - Jaeger, Carsten
A1 - Zaidi, N.
T1 - Abundance, fatty acid composition and saturation index of neutral lipids in colorectal cancer cell lines
N2 - Lipid droplets, the dynamic organelles that store Triglycerides (TG) and cholesterol esters (CE), are highly accumulated in colon cancer cells. This work studies the TG and CE subspecies profile in colon carcinoma cell lines, SW480 derived from primary tumor, and SW620 derived from a metastasis of the same tumor. It was previously reported that the total TG and CE content is dramatically higher in SW620 cells; however, TG and CE subspecies profile has not been investigated in detail. The work presented here confirms that the total TG and CE Content is significantly higher in the SW620 cells. Moreover, the fatty acid (FA) composition of TG is significantly altered in the SW620 cells, with significant decrease in the abundance of saturated triglycerides. This resulted in a significantly decreased TG saturation index in the SW620 cells. The saturation index of CE was also significantly decreased in the SW620 cells.
KW - Mass Spectroscopy
KW - Metabolomics
KW - Cancer
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533504
DO - https://doi.org/10.18388/abp.2020_5465
VL - 68
IS - 1
SP - 1
EP - 4
PB - ABP Acta Biochimica Polonica
AN - OPUS4-53350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ritter, B.
A1 - Krahl, T.
A1 - Rurack, Knut
A1 - Kemnitz, E.
T1 - Nanoscale CaF2 doped with Eu3+ and Tb3+ through fluorolytic sol-gel synthesis
N2 - In this article, the high potential of the fluorolytic sol–gel process to synthesize nanoscopic rare earth-doped calcium fluoride sols is shown. Through a fluorolytic sol–gel process we manage to achieve spherical monodisperse ~5 nm sized nanoparticles using a simple and reproducible one-pot-wet chemical route at room temperature. The as-synthesized clear sols exhibit an intense red and green luminescence under UV excitation at room temperature. A spectroscopic study of the sols revealed the characteristic transitions 5D0 → 7FJ of Eu3+ and 5D4 → 7FJ of Tb3+, with 5D0 → 7F2 (611 nm) of Eu3+ and 5D4 → 7F4 (581 nm) of Tb3+ as the most prominent transitions. This facile synthetic strategy is also valuable for developing other luminescent nanoparticles.
KW - Calciumfluorid
KW - Europium
KW - Lumineszenz
KW - Nanopartikel
KW - Sol-Gel-Synthese
KW - Terbium
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-320120
DO - https://doi.org/10.1039/c4tc01073f
SN - 2050-7526
SN - 2050-7534
VL - 2
IS - 40
SP - 8607
EP - 8613
PB - Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-32012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kramer, Claus
A1 - Ried, Peter
A1 - Mahn, Stefan
A1 - Richter, Silke
A1 - Langhammer, Nicole
A1 - Kipphardt, Heinrich
T1 - Design and application of a versatile gas calibration for non-metal determination by carrier gas hot extraction
N2 - In carrier gas hot extraction the calibration of low amounts of non-metals with masses of a few micrograms with small uncertainty remains a challenge. To achieve high flexibility a high precision gas mixture pump was combined with an automated syringe drive. The gas mixing pump allows filling the syringe with different gas compositions; the automated syringe drive allows matching to modulate the signal profiles to those of real samples. The system was designed and its experimental potential explored. The resulting calibration curves were comparable to those obtained by calibration using solid materials of sufficient purity and stoichiometry. However smaller uncertainties and lower limits of quantification (i.e. 0.5 µg and 0.6 µg for O and N, respectively) were found using the gas calibration device.
KW - Non-metal determination
KW - CGHE
KW - Gas calibration
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-336130
DO - https://doi.org/10.1039/c5ay00845j
SN - 1759-9660
SN - 1759-9679
VL - 7
IS - 13
SP - 5468
EP - 5475
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-33613
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lempke, L.
A1 - Fischer, Tobias
A1 - Bell, Jérémy
A1 - Kraus, Werner
A1 - Rurack, Knut
A1 - Krause, N.
T1 - Gold-catalyzed allene cycloisomerization for pyrrole synthesis: towards highly fluorinated BODIPY dyes
N2 - A novel synthetic strategy toward highly fluorinated BODIPY dyes with exceptional photostabilities relying on sustainable gold catalysis has been developed. A key to the tailored pyrrole precursors is the gold catalysis performed in ionic liquids as the reaction medium, allowing a facile recycling of the catalysts. The dyes prepared are well-matching with the spectral windows of popular rhodamine dyes and possess high brightness while showing a distinctly higher photostability than the rhodamines especially in aprotic solvents.
KW - Gold-Katalyse
KW - BODIPY-Farbstoffe
KW - Photostabilität
KW - Fluor-Substitution
KW - Fluoreszenz
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344692
DO - https://doi.org/10.1039/c4ob02671c
SN - 1477-0520
SN - 1477-0539
VL - 13
IS - 12
SP - 3787
EP - 3791
PB - RSC
CY - Cambridge
AN - OPUS4-34469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pascual, L.
A1 - Baroja, I.
A1 - Aznar, E.
A1 - Sancenón, F.
A1 - Marcos, M. Dolores
A1 - Murguía, J.R.
A1 - Amorós, P.
A1 - Rurack, Knut
A1 - Martínez-Mánez, Ramon
T1 - Oligonucleotide-capped mesoporous silica nanoparticles as DNA-responsive dye delivery systems for genomic DNA detection
N2 - New hybrid oligonucleotide-capped mesoporous silica nanoparticles able to detect genomic DNA were designed.
KW - Gesteuerte Materialien
KW - Mycoplasma
KW - Mesoporöse Träger
KW - Sonden
KW - DNA
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-321357
UR - http://pubs.rsc.org/en/content/articlepdf/2015/cc/c4cc08306g
DO - https://doi.org/10.1039/C4CC08306G
SN - 0022-4936
SN - 0009-241x
SN - 1359-7345
SN - 1364-548x
VL - 51
IS - 8
SP - 1414
EP - 1416
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-32135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Rurack, Knut
A1 - Hecht, Mandy
T1 - Loading and Release of Charged and Neutral Fluorescent Dyes into and from Mesoporous Materials: A Key Role for Sensing Applications
N2 - The aim of this study is to determine the efficiency of loading and release of several zwitterionic, neutral, anionic and cationic dyes into/from mesoporous nanoparticles to find the optimum loading and release conditions for their application in detection protocols. The loading is carried out for MCM-41 type silica supports suspended in phosphate-buffered saline (PBS) buffer (pH 7.4) or in acetonitrile, involving the dyes (rhodamine B chloride, rhodamine 101 chloride, rhodamine 101 perchlorate, rhodamine 101 inner salt, meso-(4-hydroxyphenyl)-boron–dipyrromethene (BODIPY), sulforhodamine B sodium salt and fluorescein 27). As a general trend, rhodamine-based dyes are loaded with higher efficiency, when compared with BODIPY and fluorescein dyes. Between the rhodamine-based dyes, their charge and the solvent in which the loading process is carried out play important roles for the amount of cargo that can be loaded into the materials. The delivery experiments carried out in PBS buffer at pH 7.4 reveal for all the materials that anionic dyes are more efficiently released compared to their neutral or cationic counterparts. The overall best performance is achieved with the negatively charged sulforhodamine B dye in acetonitrile. This material also shows a high delivery degree in PBS buffer.
KW - Mesoporous materials
KW - Charged dyes
KW - Neutral dyes
KW - Dye loading optimisation
KW - Dye release
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522596
UR - https://www.mdpi.com/2072-666X/12/3/249
DO - https://doi.org/10.3390/mi12030249
VL - 12
IS - 3
SP - 249
PB - MDPI
AN - OPUS4-52259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kimani, Martha Wamaitha
A1 - Beyer, S.
A1 - El-Schich, Z.
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Gjörloff-Wingren, A.
T1 - Imprinted Particles for Direct Fluorescence Detection of Sialic Acid in Polar Media and on Cancer Cells with Enhanced Control of Nonspecific Binding
N2 - Glycoproteins are abundant on the cell surface of mammals, providing structural support, modulating cell Membrane properties, and acting as signaling agents. Variation of glycosylation patterns has been found to indicate various disease states, including cell malignancy. Sialic acid (SA) is present as a terminating group on cell-surface glycans, and its overexpression has been linked to several types of cancer. Detection of SA on the cell surface is therefore critical for detection of cancer in its early stages. In this work, a fluorescent molecularly imprinted polymer layer targeting SA was synthesized on the surface of silica-coated polystyrene (PS) particles. Compared to previous works, a PS core supplies a lighter, lower-density support for improved suspension stability and scattering properties. Moreover, their smaller size provides a higher surface-area-to-volume ratio for binding. The incorporation of a fluorescent monomer in the MIP shell allowed for simple and rapid determination of binding specificity in polar media due to a deprotonation−reprotonation interaction mechanism between the fluorescent monomer and SA, which led to spectral changes.
Upon titration of the MIP particles with SA in suspension, an increase in fluorescence emission of the particles was observed, with the MIP particles binding SA more selectively compared to the nonimprinted polymer (NIP) control particles. In cell staining experiments performed by flow cytometry, the binding behavior of the MIP particles compared favorably with that of SA-binding lectins. NIPs prepared with a “dummy” template served as a better negative control in cell binding assays due to the favorable inward orientation of template-binding functional groups in the polymer shell, which reduced nonspecific binding. The results show that fluorescent MIPs targeting SA are a promising tool for in vitro fluorescence staining of cancerous cells and for future diagnosis of cancer at early stages.
KW - Flow cytometry
KW - Sialic acid
KW - Fluorescence
KW - Molecularly imprinted polymers
KW - Cancer cells
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525216
DO - https://doi.org/10.1021/acsapm.0c01353
VL - 3
IS - 5
SP - 2363
EP - 2373
PB - American Chemical Society
AN - OPUS4-52521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pu, Y.
A1 - Lawrence, M. J.
A1 - Celorrio, V.
A1 - Wang, Q.
A1 - Gu, M.
A1 - Sun, Z.
A1 - Agudo Jácome, Leonardo
A1 - Russell, A. E.
A1 - Huang, L.
A1 - Rodriguez, P.
T1 - Nickel confined in 2D earth-abundant oxide layers for highly efficient and durable oxygen evolution catalysts
N2 - Low cost, high-efficiency catalysts towards water splitting are urgently required to fulfil the increasing demand for energy. In this work, low-loading (<20 wt%) Ni-confined in layered metal oxide anode catalysts (birnessite and lepidocrocite titanate) have been synthesized by facile ion exchange methodology and subjected to systematic electrochemical studies. It was found that Ni-intercalated on K-rich birnessite (Ni-KMO) presents an onset overpotential (ηonset) as low as 100 mV and overpotential at 10 mA cm−2 (η10) of 206 mV in pH = 14 electrolyte. By combining electrochemical methods and X-ray absorption and emission spectroscopies (XAS and XES), we demonstrate Ni sites are the active sites for OER catalysis and that the Mn3+ sites facilitate Ni intercalation during the ion-exchange process, but display no observable contribution towards OER activity. The effect of the pH and the nature of the supporting electrolyte on the electrochemical performance was also evaluated.
KW - Confined catalyst
KW - Low-loading
KW - Layered manganese oxide
KW - Oxygen evolution reaction
KW - Transmission electron microscopy (TEM)
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515027
DO - https://doi.org/10.1039/D0TA04031B
SN - 2050-7496
SN - 2050-7488
VL - 8
IS - 26
SP - 13340
EP - 13350
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-51502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Q.
A1 - Shinde, S.
A1 - Grasso, G.
A1 - Caroli, A.
A1 - Abouhany, R.
A1 - Lanzillotta, M.
A1 - Pan, G.
A1 - Wan, Wei
A1 - Rurack, Knut
A1 - Sellergren, B.
T1 - Selective detection of phospholipids using molecularly imprinted fluorescent sensory core-shell particles
N2 - Sphingosine-1-phosphate (S1P) is a bioactive sphingo-lipid with a broad range of activities coupled to its role in G-protein coupled receptor signalling. Monitoring of both intra and extra cellular levels of this lipid is challenging due to its low abundance and lack of robust affinity assays or sensors. We here report on fluorescent sensory core-shell molecularly imprinted polymer (MIP) particles responsive to near physiologically relevant levels of S1P and the S1P receptor modulator fingolimod phosphate (FP) in spiked human serum samples. Imprinting was achieved using the tetrabutylammonium (TBA) salt of FP or phosphatidic acid (DPPA·Na) as templates in combination with a polymerizable nitrobenzoxadiazole (NBD)-urea monomer with the dual role of capturing the phospho-anion and signalling its presence. The monomers were grafted from ca 300 nm RAFT-modified silica core particles using ethyleneglycol dimethacrylate (EGDMA) as crosslinker resulting in 10–20 nm thick shells displaying selective fluorescence response to the targeted lipids S1P and DPPA in aqueous buffered media. Potential use of the sensory particles for monitoring S1P in serum was demonstrated on spiked serum samples, proving a linear range of 18–60 μM and a detection limit of 5.6 μM, a value in the same range as the plasma concentration of the biomarker.
KW - Molecularly imprinted polymers
KW - Phospholipids
KW - Fluorescence
KW - Dye monomers
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509485
DO - https://doi.org/10.1038/s41598-020-66802-3
SN - 2045-2322
VL - 10
IS - 1
SP - 9924
PB - Nature Research
CY - London
AN - OPUS4-50948
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gadelmeier, C.
A1 - Haas, S.
A1 - Lienig, T.
A1 - Manzoni, Anna Maria
A1 - Feuerbacher, M.
A1 - Glatzel, U.
T1 - Temperature Dependent Solid Solution Strengthening in the High Entropy Alloy CrMnFeCoNi in Single Crystalline State
N2 - The main difference between high entropy alloys and conventional alloys is the solid solution strengthening effect, which shifts from a single element to a multi-element matrix. Little is known about the effectiveness of this effect at high temperatures. Face-centered cubic, equiatomic, and single crystalline high entropy alloy CrMnFeCoNi was pre-alloyed by arc-melting and cast as a single Crystal using the Bridgman process. Mechanical characterization by creep testing were performed at temperatures of 700, 980, 1100, and 1200°C at different loads under vacuum and compared to single-crystalline pure nickel. The results allow a direct assessment of the influence of the chemical composition without any disturbance by grain boundary sliding or diffusion. The results indicate different behaviors of single crystalline pure nickel and CrMnFeCoNi. At 700°C CrMnFeCoNi is more creep-resistant than Ni, but at 980°C both alloys show a nearly similar creep strength. Above 980°C the creep behavior is identical and the solid solution strengthening effect of the CrMnFeCoNi alloy disappears.
KW - High entropy alloys
KW - Single crystal
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514572
DO - https://doi.org/10.3390/met10111412
VL - 10
IS - 11
SP - 1412
PB - MDPI
AN - OPUS4-51457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Noureen, N.
A1 - Shah, F. A.
A1 - Lisec, Jan
A1 - Usman, H.
A1 - Khalid, M.
A1 - Munir, R.
A1 - Zaidi, N.
T1 - Revisiting the association between human leukocyte antigen and end-stage renal disease
N2 - Multiple works have studied possible associations between human leukocyte antigen (HLA) alleles and end stage renal disease (ESRD) showing, however, contradictory and inconsistent results. Here, we revisit the association between ESRD and HLA antigens, comparing HLA polymorphism (at HLA-A, -B, -C, -DRB1, -DQB1 and DQA1 loci) in ESRD patients (n = 497) and controls (n = 672). Our data identified several HLA alleles that displayed a significant positive or negative association with ESRD. We also determined whether heterozygosity or homozygosity of the ESRD-associated HLA alleles at different loci could modify the prevalence of the disease. Few HLA allele combinations displayed significant associations with ESRD, among which A*3_26 combination showed the highest strength of association (OR = 4.488, P≤ 0.05) with ESRD. Interestingly, the age of ESRD onset was not affected by HLA allele combinations at different loci. We also performed an extensive literature analysis to determine whether the association of HLA to ESRD can be similar across different ethnic groups. Our analysis showed that at least certain HLA alleles, HLA-A*11, HLA-DRB1*11, and HLA-DRB1*4, display a significant association with ESRD in different ethnic groups. The findings of our study will help in determining possible protective or susceptible roles of various HLA alleles in ESRD.
KW - Cancer
KW - Human leukocyte antigen (HLA)
KW - Renal disease
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512651
DO - https://doi.org/10.1371/journal.pone.0238878
SN - 1932-6203
VL - 15
IS - 9
SP - e0238878
AN - OPUS4-51265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohring, Wencke
A1 - Karafiludis, Stephanos
A1 - Manzoni, Anna Maria
A1 - Laplanche, G.
A1 - Schneider, M.
A1 - Stephan-Scherb, Christiane
T1 - High-Temperature Corrosion of High- and Medium-Entropy Alloys CrMnFeCoNi and CrCoNi Exposed to a Multi-Oxidant Atmosphere H2O–O2–SO2
N2 - AbstractThe high-temperature corrosion behaviors of the equimolar CrCoNi medium-entropy alloy and CrMnFeCoNi high-entropy alloy were studied in a gas atmosphere consisting of a volumetric mixture of 10% H2O, 2% O2, 0.5% SO2, and 87.5% Ar at 800 °C for up to 96 h. Both alloys were initially single-phase fcc with a mean grain size of ~ 50 μm and a homogeneous chemical composition. The oxide layer thickness of CrMnFeCoNi increased linearly with exposure time while it remained constant at ~ 1 μm for CrCoNi. A Cr2O3 layer and minor amounts of (Co,Ni)Cr2O4 developed on the latter while three oxide layers were detected on the former, i.e., a thin and continuous chromium rich oxide layer at the oxide/alloy interface, a dense (Mn,Cr)3O4 layer in the center and a thick and porous layer of Mn3O4 and MnSO4 at the gas/oxide interface. Additionally, a few metal sulfides were observed in the CrMnFeCoNi matrix. These results were found to be in reasonable agreement with thermodynamic calculations.
KW - high entropy alloys
KW - corrosion
KW - oxidation
KW - scanning electron microscopy
KW - sulfidation
KW - CrMnFeCoNi
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594189
DO - https://doi.org/10.1007/s44210-023-00026-8
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-59418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Manzoni, Anna Maria
A1 - Lopez-Galilea, I.
A1 - Ruttert, B.
A1 - Laplanche, G.
A1 - Agudo Jácome, Leonardo
T1 - Influence of cooling rate on the microstructure and room temperature mechanical properties in the refractory AlMo0.5NbTa0.5TiZr superalloy
N2 - Refractory chemically complex alloys with bcc-based microstructures show great potential for high-temperature applications but most of them exhibit limited room-temperature ductility, which remains a challenge. One such example is the AlMo0.5NbTa0.5TiZr alloy, mainly consisting of a nano-scaled structure with an ordered B2 matrix and a high-volume fraction of aligned cuboidal and coherently embedded A2 precipitates. This work aims to investigate how the cooling rate after hot isostatic pressing of the AlMo0.5NbTa0.5TiZr alloy affects its microstructure and its resulting hardness and fracture toughness at room temperature. A slow cooling rate of 5 °C/min leads to a coarse microstructure consisting of aligned slabs (mean A2 precipitate ≈ 25 nm) with a nanohardness of about 8 GPa. In contrast, after the fastest cooling rate (30 °C/min), the A2 precipitates become more cubic with an edge length of ≈ 16 nm, resulting in an increase in nanohardness by 10 %. The fracture toughness is roughly independent of the cooling rate and its mean value (≈ 4.2 MPa∙m1/2) resembles that of some B2 intermetallics and other A2/B2 alloys. As the lattice misfit between the A2 and B2 phases is known to play a key role in microstructure formation and evolution, its temperature dependence between 20 and 900 °C was investigated. These findings offer insights into the evolution of the microstructure and room-temperature mechanical properties of the AlMo0.5NbTa0.5TiZr alloy, which could help the development of advanced chemically complex alloys.
KW - High entropy alloy
KW - Lattice misfit
KW - Scanning electron microscopy
KW - Transmission electron microscopy
KW - X-ray diffraction
KW - Refractory alloy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572809
DO - https://doi.org/10.1016/j.jallcom.2023.169871
SN - 0925-8388
VL - 949
SP - 169871
PB - Elsevier B.V.
AN - OPUS4-57280
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Lepore, G. O.
A1 - Widom, M.
A1 - Kasatikov, S.
A1 - Manzoni, Anna Maria
T1 - How Atomic Bonding Plays the Hardness Behavior in the Al–Co–Cr–Cu–Fe–Ni High Entropy Family
N2 - A systematic study on a face‐centered cubic‐based compositionally complex alloy system Al–Co–Cr–Cu–Fe–Ni in its single‐phase state is carried out, where a mother senary compound Al₈Co₁₇Cr₁₇Cu₈Fe₁₇Ni₃₃ and five of its suballoys, obtained by removing one element at a time, are investigated and exhaustively analyzed determining the contribution of each alloying element in the solid solution. The senary and the quinaries are compared using experimental techniques including X‐ray absorption spectroscopy, X‐ray diffraction, transmission electron microscopy, and first principles hybrid Monte Carlo/molecular dynamics simulations. Chemical short‐range order and bond length distances have been determined both at the experimental and computational level. Electronic structure and local atomic distortions up to 5.2 Å have been correlated to the microhardness values. A linear regression model connecting hardness with local lattice distortions is presented.
KW - High entropy alloys
KW - EXAFS
KW - Short-range order
KW - Microhardness
KW - Alloy design
KW - Transmission electron microscopy
KW - Lattice distortion
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593333
DO - https://doi.org/https://doi.org/10.1002/smsc.202300225
SN - 2688-4046
SP - 1
EP - 12
PB - Wiley
CY - Weinheim
AN - OPUS4-59333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matschat, Ralf
A1 - Richter, Silke
A1 - Vogl, Jochen
A1 - Kipphardt, Heinrich
T1 - On the way to SI traceable primary transfer standards for amount of substance measurements in inorganic chemical analysis
N2 - During its 25 years of existence, the Inorganic Analysis Working Group of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM IAWG) has achieved much in establishing comparability of measurement results. Impressive work has been done on comparison exercises related to real-world problems in fields such as ecology, food, or health. In more recent attempts, measurements and comparisons were focused on calibration solutions which are the basis of most inorganic chemical measurements. This contribution deals with the question of how to achieve full and transparent SI traceability for the values carried by such solutions. Within this framework, the use of classical primary methods (CPMs) is compared to the use of a primary difference method (PDM). PDM is a method with a dual character, namely a metrological method with a primary character, based on the bundling of many measurement methods for individual impurities, which lead to materials with certified content of the main component. As in classical methods, where small corrections for interferences are accepted, in PDM, many small corrections are bundled. In contrast to classical methods, the PDM is universally applicable to all elements in principle. Both approaches can be used to certify the purity (expressed as mass fraction of the main element) of a high-purity material. This is where the metrological need of National Metrology Institutes (NMIs) for analytical methods meet the challenges of analytical methods. In terms of methods, glow discharge mass spectrometry (GMDS) with sufficient uncertainties for sufficiently small impurity contents is particularly noteworthy for the certification of primary transfer standards (PTS), and isotope dilution mass spectrometry (IDMS), which particularly benefits from PTS (back-spikes) with small uncertainties, is particularly noteworthy for the application. The corresponding relative uncertainty which can be achieved using the PDM is very low (< 10−4). Acting as PTS, they represent the link between the material aspect of the primary calibration solutions and the immaterial world of the International System of Units (SI). The underlying concepts are discussed, the current status of implementation is summarised, and a roadmap of the necessary future activities in inorganic analytical chemistry is sketched. It has to be noted that smaller measurement uncertainties of the purity of high-purity materials not only have a positive effect on chemical measurements, but also trigger new developments and findings in other disciplines such as thermometry or materials science.
KW - Inorganic chemical analysis
KW - Primary transfer standards (PTSs)
KW - Traceability
KW - Classical primary measurement method (CPM)
KW - Primary difference measurement method (PDM)
KW - Metrology in chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572743
DO - https://doi.org/10.1007/s00216-023-04660-4
SN - 1618-2642
SN - 1618-2650
VL - 415
SP - 3057
EP - 3071
PB - Springer
CY - Berlin
AN - OPUS4-57274
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Roesch, Philipp
A1 - Wittwer, Philipp
A1 - Piechotta, Christian
A1 - Lisec, Jan
A1 - Sommerfeld, Thomas
A1 - Kluge, Stephanie
A1 - Herzel, Hannes
A1 - Huthwelker, T.
A1 - Borca, C.
A1 - Simon, Franz-Georg
T1 - Levels of per- and polyfluoroalkyl substances (PFAS) in various wastewater-derived fertilizers - Analytical investigations from different perspectives
N2 - Solid wastewater-based fertilizers were screened for per- and polyfluoroalkyl substances (PFAS) by the extractable organic fluorine (EOF) sum parameter method. The EOF values for ten sewage sludges from Germany and Switzerland range from 154 to 7209 mg kg−1. For thermal treated sewage sludge and struvite the EOF were lower with values up to 121 mg kg−1. Moreover, the application of PFAS targeted
and suspect screening analysis of selected sewage sludge samples showed that only a small part of the EOF sum parameter values can be explained by the usually screened legacy PFAS. The hitherto unknown part of EOF sum parameter contains also fluorinated pesticides, pharmaceutical and aromatic compounds. Because these partly fluorinated compounds can degrade to (ultra-)short PFAS in wastewater treatment plants they should be considered as significant sources of organic fluorine in the environment. The combined results of sum parameter analysis and suspect screening reveal the need to update current regulations, such as the German fertilizer ordinance, to focus not solely on a few selected PFAS such as perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) but
consider an additional sum parameter approach as a more holistic alternative. Moreover, diffusion gradient in thin-films (DGT) passive samplers were utilized as an alternative simplified extraction method for PFAS in solid wastewater-based fertilizers and subsequently quantified via combustion ion chromatography. However, the DGT method was less sensitive and only comparable to the EOF values
of the fertilizers in samples with >150 mg kg−1, because of different diffusion properties for various PFAS, but also kinetic exchange limitations.
KW - Combustion ion chromatography
KW - Per- and polyfluoroalkyl substances (PFAS)
KW - Sewage sludge
KW - Fertilizer
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583429
DO - https://doi.org/10.1039/d3va00178d
SN - 2754-7000
VL - 2
IS - 10
SP - 1436
EP - 1445
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-58342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bhattacharya, Biswajit
A1 - Rurack, Knut
T1 - Ratiometric Molecularly Imprinted Particle Probes for Reliable Fluorescence Signaling of Carboxylate-Containing Molecules
N2 - In addition to sensitivity, selectivity, and portability, chemical sensing systems must generate reliable signals and offer modular configurability to address various small molecule targets, particularly in environmental applications. We present a versatile, modular strategy utilizing ratiometric molecularly imprinted particle probes based on BODIPY indicators and dyes for recognition and internal referencing. Our approach employs polystyrene core particles doped with a red fluorescent BODIPY as an internal standard, providing built-in reference for environmental influences. A molecularly imprinted polymer (MIP) recognition shell, incorporating a green-fluorescent BODIPY indicator monomer with a thiourea binding site for carboxylate containing analytes, is grafted from the core particles in the presence of the analyte as the template. The dual-fluorescent MIP probe detects fexofenadine as the model analyte with a change in green emission signal referenced against a stable red signal, achieving a detection limit of 0.13 μM and a broad dynamic range from 0.16 μM to 1.2 mM, with good discrimination against other antibiotics in acetonitrile. By selecting a versatile dye scaffold and recognition element, this approach can be extended to other carboxylate-containing analytes and/or wavelength combinations, potentially serving as a robust multiplexing platform.
KW - Core-shell particles
KW - Molecular imprinting
KW - Pharmaceutical contaminants
KW - Self-referenced measurements
KW - Fluorescence
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609385
DO - https://doi.org/10.1021/acsami.4c09990
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-60938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peter, Elisa K.
A1 - Jaeger, Carsten
A1 - Lisec, Jan
A1 - Peters, R. Sven
A1 - Mourot, Rey
A1 - Rossel, Pamela E.
A1 - Tranter, Martyn
A1 - Anesio, Alexandre M.
A1 - Benning, Liane G.
T1 - Endometabolic profiling of pigmented glacier ice algae: the impact of sample processing
N2 - Introduction
Glacier ice algae, mainly Ancylonema alaskanum and Ancylonema nordenskiöldi, bloom on Greenland Ice Sheet bare ice surfaces. They significantly decrease surface albedo due to their purple-brown pigmentation, thus increasing melt. Little is known about their metabolic adaptation and factors controlling algal growth dynamics and pigment formation. A challenge in obtaining such data is the necessity of melting samples, which delays preservation and introduces bias to metabolomic analysis. There is a need to evaluate the physiological response of algae to melting and establish consistent sample processing strategies for metabolomics of ice microbial communities.
Objectives
To address the impact of sample melting procedure on metabolic characterization and establish a processing and analytical workflow for endometabolic profiling of glacier ice algae.
Methods
We employed untargeted, high-resolution mass spectrometry and tested the effect of sample melt temperature (10, 15, 20 °C) and processing delay (up to 49 h) on the metabolome and lipidome, and complemented this approach with cell counts (FlowCam), photophysiological analysis (PAM) and diversity characterization.
Results and Conclusion
We putatively identified 804 metabolites, with glycerolipids, glycerophospholipids and fatty acyls being the most prominent superclasses ( 50% of identified metabolites). Among the polar metabolome, carbohydrates and amino acid-derivatives were the most abundant. We show that 8% of the metabolome is affected by melt duration, with a pronounced decrease in betaine membrane lipids and pigment precursors, and an increase in phospholipids. Controlled fast melting at 10 °C resulted in the highest consistency, and is our recommendation for future supraglacial metabolomics studies.
KW - Metabolic profiling
KW - Mass Spectrometry
KW - Ice algae
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607921
DO - https://doi.org/10.1007/s11306-024-02147-6
VL - 20
IS - 5
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-60792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tobias, Charlie
A1 - López-Puertollano, Daniel
A1 - Abad-Somovilla, Antonio
A1 - Mercader, J. V.
A1 - Abad-Fuentes, A.
A1 - Rurack, Knut
T1 - Development of Simple and Rapid Bead-Based Cytometric Immunoassays Using Superparamagnetic Hybrid Core−Shell Microparticles
N2 - Flow cytometry-based immunoassays are valuable in biomedical research and clinical applications due to their high throughput and multianalyte capability, but their adoption in areas such as food safety and environmental monitoring is limited by long assay times and complex workflows. Rapid, simplified bead-based cytometric immunoassays are needed to make these methods viable for point-of-need applications, especially with the increasing accessibility of miniaturized cytometers. This work introduces superparamagnetic hybrid polystyrene-silica core−shell microparticles as promising alternatives to conventional polymer beads in competitive cytometric immunoassays. These beads, featuring high specificity, sensitivity, and excellent handling capabilities via magnetic separation, were evaluated with three different antibodies and binding methods, showing variations in signal intensity based on the antibody and its attachment method. The optimal performance was achieved through a secondary antibody binding approach, providing strong and consistent signals with minimal uncertainty. The optimized protocol made it possible to achieve a detection limit of 0.025 nM in a total assay time of only 15 min and was successfully used to detect ochratoxin A (OTA) in raw flour samples. This work highlights the potential of these beads as versatile tools for flow cytometry-based immunoassays, with significant implications for food safety, animal health,
environmental monitoring, and clinical diagnostics.
KW - Immunoassays
KW - Bead-based
KW - Core-shell particles
KW - Cytometry
KW - Mycotoxins
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610593
DO - https://doi.org/10.1021/acsmeasuresciau.4c00038
SP - 1
EP - 11
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-61059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gadelmeier, C.
A1 - Agudo Jácome, Leonardo
A1 - Suárez Ocano, Patricia
A1 - Glatzel, U.
T1 - Effect of stacking fault energy (SFE) of single crystal, equiatomic CrCoNi and Cantor alloy on creep resistance
N2 - Compared to mechanisms like solid solution strengthening, the stacking fault energy (SFE) should be considered as a further factor that influences the material properties. The effect of SFE of alloys or individual elements on strength and resistance can vary considerably. In the high-temperature regime above 700 ◦C, there are still significant gaps in the knowledge about the effect of the SFE on the mechanical properties of single-phase alloys. The effect of SFE on creep resistance of two face-entered cubic equiatomic medium and high entropy alloys, CrCoNi and CrMnFeCoNi, respectively, is evaluated to fill parts of these gaps. Using the Bridgman solidification process, the alloys were produced as single crystals and crept under vacuum at 700 ◦C up to 1100 ◦C. This work shows a significant impact of the lower SFE of CrCoNi on the creep behavior compared to the results of previous investigations of CrMnFeCoNi. The creep resistance of the former is higher over the complete temperature range. At very high temperatures, the strengthening effect of the stacking faults is significantly present. The formation of tetragonal stacking faults and extended dislocation nodes can be identified as the reason for this effect.
KW - Medium entropy alloy
KW - MEA
KW - HEA
KW - Single crystal
KW - CrCoNi
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602620
DO - https://doi.org/10.1016/j.msea.2024.146779
SN - 0921-5093
VL - A 908
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-60262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mansurova, Maria
A1 - Johann, Sergej
A1 - Kohlhoff, Harald
A1 - Rurack, Knut
A1 - Bartholmai, Matthias
A1 - Bell, Jérémy
T1 - On-Site Analytical Tool Based on Crude Oil Fluorescence and Chemometrics for the Rapid Determination of the Nature and Essential Properties of Oil Spills
N2 - With the reduction of large oil spills because of stricter regulations and safety measures, the question of how to manage smaller oil spills arises. Few on-site analytical tools are available for first responders or other law enforcement personnel to rapidly test for crude oil in the early management of localized polluted areas. The approach reported here relies on well-described computer-assisted multivariate data analysis of the intrinsic fluorescence fingerprints of crude oils to build a multivariate model for the rapid classification of crude oils and the prediction of their properties. Thanks to a dedicated robust portable reader, the method allowed classification and accurate prediction of various properties of crude oil samples like density (according to API, the American Petroleum Institute and viscosity as well as composition parameters such as volume fractions of paraffins or aromatics. In this way, autonomous operation in on-site or in-the-field applications becomes possible based on the direct (undiluted and untreated) measurement of samples and a rapid, tablet-operated readout system to yield a robust and simple analytical test with superior performance. Testing in real-life scenarios allowed the successful classification and prediction of a number of oil spill samples as well as weathered samples that closely resemble samples collected by first responders.
KW - Oil spills
KW - Fluorescence
KW - PCA
KW - Petroleum
KW - Rapid test
KW - Portable
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595442
DO - https://doi.org/10.1021/acsestwater.3c00648
VL - 4
IS - 2
SP - 621
EP - 627
PB - American Chemical Society (ACS)
AN - OPUS4-59544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tukhmetova, Dariya
A1 - Lisec, Jan
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Development of an Online Isotope Dilution CE/ICP–MS Method for the Quantification of Sulfur in Biological Compounds
N2 - We report an analytical methodology for the quantification of sulfur in biological molecules via a speciesunspecific postcolumn isotope dilution (online ID) approach using capillary electrophoresis (CE) coupled online with inductively coupled plasma−mass spectrometry (online ID CE/ICP−MS).
The method was optimized using a mixture of standard compounds including sulfate, methionine, cysteine, cystine, and albumin, yielding compound recoveries between 98 and 105%. The quantity of sulfur is further converted to the quantity of the compounds owing to the prior knowledge of the sulfur content in the molecules. The limit of detection and limit of quantification of sulfur in the compounds were 1.3−2.6 and 4.1−8.4 mg L−1, respectively, with a correlation coefficient of 0.99 within the concentration range of sulfur of 5−100 mg L−1. The capability of the method was extended to quantify albumin in its native matrix (i.e., in serum) using experimentally prepared serum spiked with a pure albumin standard for validation. The relative expanded uncertainty of the method for the quantification of albumin was 6.7% (k = 2). Finally, we tested the applicability of the method on real samples by the analysis of albumin in bovine and human sera. For automated data assessment, a software application (IsoCor) which was developed by us in a previous work was developed further for handling of online ID data. The method has several improvements compared to previously published setups: (i) reduced adsorption of proteins onto the capillary wall owing to a special capillary-coating procedure, (ii) baseline separation of the compounds in less than 30 min via CE, (iii) quantification of several sulfur species within one run by means of the online setup, (iv) SI traceability of the quantification results through online ID, and (v) facilitated data processing of the transient signals using the IsoCor application. Our method can be used as an accurate approach for quantification of proteins and other biological molecules via sulfur analysis in complex matrices for various fields, such as environmental, biological, and pharmaceutical studies as well as clinical diagnosis.
Sulfur is an essential element in living organisms, where it plays important roles in various biological processes, such as protein synthesis, enzyme activity, and antioxidant defense. However, the biological effects of different sulfur species can vary widely, and imbalances in sulfur speciation have been observed in a range of diseases, including cancer, Alzheimer’s disease, and diabetes.1−3 The accurate quantification of sulfur and its species in biological samples requires sensitive and selective analytical techniques. In recent years, separation techniques coupled online with inductively coupled plasma−mass spectrometry (ICP−MS) have emerged as powerful online analytical tools complementary to molecular spectrometric methods for speciation analysis of biological compounds.
External calibration4−9 and isotope dilution (ID)10−15 are common calibration approaches applied for online quantification of sulfur species in complex samples. The ID analysis is advantageous over.
KW - Analytical Chemistry
KW - CE/MC-ICP-MS
KW - species-specific isotope information
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594736
DO - https://doi.org/10.1021/acs.analchem.3c03553
SN - 0003-2700
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-59473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kingsbery, P.
A1 - Manzoni, Anna Maria
A1 - Suárez Ocano, Patricia
A1 - Többens, D. M.
A1 - Stephan-Scherb, C.
T1 - High‐temperature KCl‐induced corrosion of high Cr and Ni alloys investigated by in‐situ diffraction
N2 - High‐temperature KCl‐induced corrosion in laboratory air was observed in situ utilizing X‐ray diffraction. High Cr‐containing model alloys (Fe‐13Cr, Fe‐18Cr‐12Ni, and Fe‐25Cr‐20Ni) were coated with KCl and exposed to dry air at 560°C. KCl‐free alloys were studied in the equivalent atmosphere as a reference. After exposure to KCl‐free environments, all alloys showed the formation of very thin oxide layers, indicating good corrosion resistance. In contrast, KCl‐bearing alloys showed distinct damage after exposure.
KW - Corrosion
KW - In-situ diffraction
KW - High-temperature corrosion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600831
DO - https://doi.org/10.1002/maco.202314224
SN - 0947-5117
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-60083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kislenko, Evgeniia
A1 - Incel, A.
A1 - Gawlitza, Kornelia
A1 - Sellergren, B.
A1 - Rurack, Knut
T1 - Towards molecularly imprinted polymers that respond to and capture phosphorylated tyrosine epitopes using fluorescent bis-urea and bis-imidazolium receptors
N2 - Early detection of cancer is essential for successful treatment and improvement in patient prognosis. Deregulation of post-translational modifications (PTMs) of proteins, especially phosphorylation, is present in many types of cancer. Therefore, the development of materials for the rapid sensing of low abundant phosphorylated peptides in biological samples can be of great therapeutic value. In this work, we have synthesised fluorescent molecularly imprinted polymers (fMIPs) for the detection of the phosphorylated tyrosine epitope of ZAP70, a cancer biomarker. The polymers were grafted as nanometer-thin shells from functionalised submicron-sized silica particles using a reversible addition-fragmentation chain-transfer (RAFT) polymerisation. Employing the combination of fluorescent urea and intrinsically cationic bis-imidazolium receptor cross-linkers, we have developed fluorescent sensory particles, showing an imprinting factor (IF) of 5.0. The imprinted polymer can successfully distinguish between phosphorylated and non-phosphorylated tripeptides, reaching lower micromolar sensitivity in organic solvents and specifically capture unprotected peptide complements in a neutral buffer. Additionally, we have shown the importance of assessing the influence of counterions present in the MIP system on the imprinting process and final material performance. The potential drawbacks of using epitopes with protective groups, which can co-imprint with targeted functionality, are also discussed.
KW - Functional monomers
KW - Molecularly imprinted polymers
KW - Phosphorylated peptides
KW - Fluorescence
KW - Core-shell particles
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588089
DO - https://doi.org/10.1039/d3tb01474f
SN - 2050-750X
SP - 1
EP - 10
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-58808
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feng, Wen
A1 - Gemming, Thomas
A1 - Giebeler, Lars
A1 - Qu, Jiang
A1 - Weinel, Kristina
A1 - Agudo Jácome, Leonardo
A1 - Büchner, Bernd
A1 - González-Martínez, Ignacio
T1 - Influence of magnetic field on electron beam-induced Coulomb explosion of gold microparticles in transmission electron microscopy
N2 - In this work we instigated the fragmentation of Au microparticles supported on a thin amorphous carbon film by irradiating them with a gradually convergent electron beam inside the Transmission Electron Microscope. This phenomenon has been generically labeled as “electron beam-induced fragmentation” or EBIF and its physical origin remains contested. On the one hand, EBIF has been primarily characterized as a consequence of beam-induced heating. On the other, EBIF has been attributed to beam-induced charging eventually leading to Coulomb explosion. To test the feasibility of the charging framework for EBIF, we instigated the fragmentation of Au particles under two different experimental conditions. First, with the magnetic objective lens of the microscope operating at full capacity, i.e. background magnetic field B = 2 T, and with the magnetic objective lens switched off (Lorenz mode), i.e. B = 0 T. We observe that the presence or absence of the magnetic field noticeably affects the critical current density at which EBIF occurs. This strongly suggests that magnetic field effects play a crucial role in instigating EBIF on the microparticles. The dependence of the value of the critical current density on the absence or presence of an ambient magnetic field cannot be accounted for by the beam-induced heating model. Consequently, this work presents robust experimental evidence suggesting that Coulomb explosion driven by electrostatic charging is the root cause of EBIF.
KW - Electron beam-induced fragmentation
KW - Coulomb explosion
KW - X-ray diffraction
KW - Lorenz transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600247
DO - https://doi.org/10.1016/j.ultramic.2024.113978
SN - 1879-2723
VL - 262
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-60024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nicolai, Marcel
A1 - Bulling, Jannis
A1 - Narayanan, M.M.
A1 - Zeipert, Henning
A1 - Prager, Jens
A1 - Henning, Bernd
T1 - Dynamic interface behavior in coupled plates: Investigating Lamb wave mode repulsion with a spring-based model
N2 - This study investigates the phenomenon of mode repulsion in Lamb waves propagating through two coupled plates with an elastic interface. Using a spring-based coupling model and the Scaled Boundary Finite Element Method, the dispersion curves of the coupled system are analyzed under various interface conditions—weak coupling, sliding boundary, and perfect coupling. This research highlights how the mechanical stiffness of the interface influences the separation of modes and the emergence of repulsion regions. A novel focus on interface displacements reveals a unique dynamic behavior within the repulsion regions, driven by in-phase and out-of-phase oscillations of the coupled plates. The findings provide a physically grounded explanation of mode repulsion, linking it to the strain patterns in the interface. This insight lays the theoretical groundwork for future applications in material characterization and non-destructive evaluation, enabling more precise selection of Lamb wave modes for scientific and industrial purposes.
KW - Lamb waves
KW - Mode repulsion
KW - Coupled plates
KW - Elastic interface
KW - Dispersion curves
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642245
DO - https://doi.org/10.1016/j.ultras.2025.107799
SN - 0041-624X
VL - 158
SP - 1
EP - 9
PB - Elsevier BV
AN - OPUS4-64224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaudhuri, Somsubhro
A1 - Krankenhagen, Rainer
A1 - Lapšanská, Ivana
A1 - Stamm, Michael
T1 - WTB-IRT: Modelling and Measurement of Thermal Contrast in Wind Turbine Rotor Blades (WTBs)
N2 - The rapid growth of wind energy infrastructure over the past two to three decades has led to an urgent need for advanced non-destructive testing (NDT) methods—both for newly installed wind turbine blades (WTBs) and for ageing components nearing the end of their service life. Among emerging techniques, passive infrared thermography (IRT) offers a promising solution by enabling contactless, time-efficient inspection based on naturally occurring thermal variations. The effectiveness of passive IRT depends on the presence of sufficient thermal contrast to distinguish surface features, subsurface structures, and defects. To better understand the possibility of obtaining such contrast in composite structures such as WTBs, a controlled study was carried out on a blade section exposed to programmed temperature transients in a climate chamber. Infrared measurements were recorded, and the thermal behaviour of the specimen was simulated using finite element models (FEM) in COMSOL Multiphysics 6.3. Although direct validation is limited by measurement uncertainties and transient effects, the comparison provides insight into the capabilities and limitations of FEM in replicating real-world thermal behaviour. This paper focuses specifically on the challenges related to the modelling approach.
T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025)
CY - Kobe, Japan
DA - 15.09.2025
KW - Thermography
KW - Wind energy
KW - Wind turbine rotor blades
KW - Windenergie Anlage Rotorblätter
KW - FEA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642308
DO - https://doi.org/10.3390/proceedings2025129015
VL - 129
IS - 1
SP - 1
EP - 5
PB - MDPI
CY - Basel
AN - OPUS4-64230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Przyklenk, A.
A1 - Balsamo, A.
A1 - O'Connor, D.
A1 - Evans, Alexander
A1 - Yandayan, T.
A1 - Akgöz, S.
A1 - Flys, O.
A1 - Zeleny, V.
A1 - Czułek, D.
A1 - Meli, F.
A1 - Ragusa, C.
A1 - Bosse, H.
T1 - New European Metrology Network for advanced manufacturing
N2 - Advanced manufacturing has been identified as one of the key enabling technologies with applications in multiple industries. The growing importance of advanced manufacturing is reflected by an increased number of publications on this topic in recent years. Advanced manufacturing requires new and enhanced metrology methods to assure the quality of manufacturing processes and the resulting products. However, a high-level coordination of the metrology community is currently absent in this field and consequently this limits the impact of metrology developments on advanced manufacturing. In this article we introduce the new European Metrology Network (EMN) for Advanced Manufacturing within EURAMET, the European Association of National Metrology Institutes (NMIs). The EMN is intended to be operated sustainably by NMIs and Designated Institutes in close cooperation with Stakeholders interested in advanced manufacturing. The objectives of the EMN are to set up a permanent stakeholder dialogue, to develop a Strategic Research Agenda for the metrology input required for advanced manufacturing technologies, to create and maintain a knowledge sharing programme and to implement a web-based service desk for stakeholders. The EMN development is supported by a Joint Network Project within the European Metrology Programme for Innovation and Research.
KW - Stakeholder
KW - Advanced manufacturing
KW - Metrology
KW - European Metrology Networks (EMNs)
KW - Strategic Research Agenda (SRA),
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530618
DO - https://doi.org/10.1088/1361-6501/ac0d25
VL - 32
IS - 11
SP - 111001
PB - IOP Publishing
AN - OPUS4-53061
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Scheuschner, Nils
A1 - Hilgenberg, Kai
T1 - In situ heat accumulation by geometrical features obstructing heat flux and by reduced inter layer times in laser powder bed fusion of AISI 316L stainless steel
N2 - Material qualification for laser powder bed fusion (L-PBF) processes are often based on results derived from additively manufactured (AM) bulk material or small density cubes, although it is well known that the part geometry has a tremendous influence on the heat flux and, therefore, on the thermal history of an AM component. This study shows experimentally the effect of simple geometrical obstructions to the heat flux on cooling behavior and solidification conditions of 316L stainless steel processed by L-PBF. Additionally, it respects two distinct inter layer times (ILT) as well as the build height of the parts. The cooling behavior of the parts is in-situ traced by infrared (IR) thermography during the built-up. The IR signals reveal significant differences in cooling conditions, which are correlated to differences in melt pool geometries. The acquired data and results can be used for validation of computational models and improvements of quality assurance.
KW - Selective laser beam melting
KW - Thermography
KW - Melt pool depth
KW - Inter layer time
KW - Ppreheating temperature
KW - Additive Manufacturing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512549
DO - https://doi.org/10.1016/j.procir.2020.09.030
VL - 94
SP - 155
EP - 160
PB - Elsevier B.V.
AN - OPUS4-51254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Azimzada, Agil
A1 - Meermann, Björn
T1 - AF4/ICP-ToF-MS for the investigation of species-specific adsorption of organometallic contaminants on natural colloidal particles
N2 - Organotin (OT) compounds, while crucial in many industrial applications, pose substantial risks to the environment and human health. The toxicity and environmental behaviour of OTs depend on their chemical form, i.e., the type and number of organic substituents. Each species thus exhibits distinct toxicity profiles and varying binding affinities to environmental colloids, which influence their mobility, bioavailability, and environmental impacts. To date, however, most studies addressed speciation and colloidal characterization separately, leaving the combined determinations of organometallics along with their carrier colloids largely elusive. Here, we develop and validate an on-line measurement system to quantify the adsorption dynamics of 10 OT species on natural colloidal particles (<500 nm). The approach integrates a versatile fractionation technique (AF4), with a state-of-the-art multi-element analyzer (ICP-ToF-MS), achieving Sn detection limits as low as 6.0 ng/L. The method separates colloid-free OT species from those bound to colloids and enables the determination of OT interactions with distinct colloidal fractions. Validated in both fractionation and detection, the method provides reliable data that could elucidate the species-specific and temporal aspects of species-colloids adsorption processes. The results feature comparative studies of 10 OT species, offering critical insights into OT mobility and distribution in environmental systems.
KW - Fractionation
KW - Speciation
KW - Adsorption
KW - Colloids
KW - Organotin
KW - AF4
KW - Nanoparticle characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625244
DO - https://doi.org/10.1016/j.jhazmat.2025.137320
SN - 1873-3336
VL - 488
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-62524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schoknecht, Ute
A1 - Kalbe, Ute
A1 - Van Zomeren, A.
A1 - Hjelmar, O.
T1 - Laboratory leaching tests on treated wood according to different harmonised test procedures
N2 - -Background-
Laboratory leaching tests on treated wood were performed during a European robustness study in the framework of the validation of a tank leaching test procedure that has been proposed for construction products in order to determine the potential release of dangerous substances which can be transferred to soil and groundwater. The release of substances has to be determined also for materials treated with biocidal products according to the requirements of the European Biocidal Products Regulation. A similar leaching test procedure was already harmonised for treated wood for this purpose. Both test procedures were applied in parallel to wood treated with the same preservative to investigate whether the results of these tests can replace each other. Additional experiments were performed to further investigate unexpected effects of L/A ratio on leaching of copper and duration of storage of treated test specimens.
-Results-
Both procedures generate similar results concerning cumulative emissions of tebuconazole, copper, dissolved organic carbon and total nitrogen. The emission rates with time are in comparable ranges for both leaching protocols. Emissions of copper increased with decreasing L/A ratios. Strong correlation of copper concentrations and dissolved organic carbon as well as total nitrogen concentrations in eluates indicates that this observation is caused by co-elution of copper with organic substances. Duration of storage of treated test specimens affected emissions for the investigated wood preservative.
-Conclusions-
Based on these findings, results from both test procedures can be used to describe leaching characteristics and avoid double testing of treated wood to fulfil the requirements of the European regulations for either biocides or construction products. Leaching of substances from treated wood is a complex process that depends on its chemical composition and ageing processes.
KW - Construction products
KW - Biocidal product
KW - Emission
KW - Leaching
KW - Tank leaching test
KW - Treated wood
KW - European regulation
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317320
UR - http://www.enveurope.com/content/26/1/25
SN - 2190-4715
SN - 2190-4707
VL - 26
SP - 25, 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-31732
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalbe, Ute
A1 - Simon, Franz-Georg
T1 - Potential use of incineration bottom ash in construction – Evaluation of the environmental impact
N2 - Knowledge of the long-term leaching behavior of potentially harmful substances is crucial for the assessment of the environmental compatibility of reusing municipal solid-waste incineration bottom ash (MSWI BA) in construction, i.e., as a road base layer.
BA fractions obtained from wet-processing aiming at the improvement of environmental quality were used to investigate the mobility of relevant substances. Eluates from laboratory-scaled leaching procedures (column percolation and lysimeters) were analyzed to learn about the long-term release of substances. Unsaturated conditions and artificial rainwater (AR) were used in the lysimeter tests to simulate field conditions. In addition, batch test eluates were generated at usual liquid-to-solid ratios (L/S) for compliance testing purposes. A variety of cations and anions was measured in the eluates.
The wet treatment reduces the leaching of chloride and particularly sulfate by more than 60%. The release of typical contaminants for the treated MSWI BA such as the heavy metals Cu and Cr was well below 1% in the conducted leaching tests.
An increase in the Sb concentration observed in the lysimeter experiments starting at L/S 0.75 L/kg and in the column experiment at L/S 4 L/kg is assumed to be related to decreasing concentrations of Ca and thus to the dissolution of sparingly soluble calcium antimonate. The same leaching mechanism applies with V, but the concentration levels observed are less critical regarding relevant limit values. However, on the long term the behavior of Sb could be problematic for the application of MSWI BA in construction.
KW - MSWI bottom ash
KW - Leaching
KW - Batch tests
KW - Lysimeter
KW - Antimony
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508421
DO - https://doi.org/10.1007/s12649-020-01086-2
SN - 1877-2641
VL - 11
IS - 12
SP - 7055
EP - 7065
PB - Springer
AN - OPUS4-50842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heisterkamp, I.
A1 - Ratte, M.
A1 - Schoknecht, Ute
A1 - Gartiser, S.
A1 - Kalbe, Ute
A1 - Ilvonen, O.
T1 - Ecotoxicological evaluation of construction products: inter-laboratory test with DSLT and percolation test eluates in an aquatic biotest battery
N2 - Background
A European inter-laboratory test with 29 participating laboratories investigated whether a battery of four ecotoxicological tests is suitable for assessing the environmental compatibility of construction products. For this purpose, a construction product was investigated with the dynamic surface leaching test (DIN CEN/TS 16637-2) and the percolation test (DIN CEN/TS 16637-3). The eluates were produced centrally by one laboratory and were tested by the participants using the following biotests: algae test (ISO 8692), acute daphnia test (ISO 6341), luminescent bacteria test (DIN EN ISO 11348), and fish egg test (DIN EN ISO 15088). As toxicity measures, EC50 and LID values were calculated.
Results
Toxic effects of the eluates were detected by all four biotests. The bacteria test was by far the most sensitive, followed by the algae test and the daphnia test; the fish egg test was the least sensitive for eluates of both leaching tests. The toxicity level of the eluates was very high in the bacteria, daphnia, and algae test, with lowest ineffective dilution values of LID = 70 to LID = 13,000 and corresponding EC50 values around or even below 1 volume percent. The reproducibility (approximated by interlaboratory variability) of the biotests was good (< 53%) to very good (< 20%), regardless of the toxicity level of the eluates. The reproducibility of the algae test was up to 80%, and thus still acceptable.
Conclusion
It can be confirmed that the combination of leaching and ecotoxicity tests is suitable to characterize with sufficient reproducibility the environmental impact posed by the release of hazardous substances from construction products.
KW - Inter-laboratory test
KW - Construction products
KW - Leaching tests
KW - Ecotoxicity tests
KW - Grouts
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529198
DO - https://doi.org/10.1186/s12302-021-00514-x
VL - 33
IS - 1
SP - Article number: 75
PB - Springer
AN - OPUS4-52919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steger, S.
A1 - Horn, Wolfgang
A1 - Eggert, G.
A1 - Krekel, C.
T1 - Are cellulose ethers safe for the conservation of artwork? New insights in their VOC activity by means of Oddy testing
N2 - Cellulose ethers, like methyl cellulose (MC) or hydroxypropyl cellulose (HPC), are widely used in conservation. They also occur as additives and rheology modifiers in various products like dispersions or gels. Do such products release harmful volatile organic compounds (VOC) during their accelerated aging? A mass testing series utilizing the Oddy test of 60 commercial cellulose ethers ranks the products in safe for permanent use (P, no corrosion), only for temporary use (T, slight corrosion), and unsuitable at all (F, heavy corrosion). Results show that 55% of the products passed the test whereas 33% are for temporary use as slight corrosion occurred on at least one metal coupon and only 11% failed the Oddy test. Raman measurements of the corrosion products identified oxides like massicot, litharge, cuprite, and tenorite among carbonates (hydrocerussite, plumbonacrite), and acetates like basic lead acetate, lead acetate trihydrate as well as lead formate as main phases. For example, commercial, industrial Klucel® G (HPC) scored a T rating through slight corrosion on the lead coupon. Basic lead acetate among other phases indicates the presence of acetic acid. Additional measurements of the sample with thermal desorption GC–MS utilizing the BEMMA scheme confirm the high acetic acid outgassing and reveal the presence of a small amount of formaldehyde.
KW - Cellulose ether
KW - Corrosion
KW - Oddy test
KW - VOC
KW - BEMMA
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547591
DO - https://doi.org/10.1186/s40494-022-00688-4
SN - 2050-7445
VL - 10
IS - 1
SP - 1
EP - 12
PB - Springer Open
AN - OPUS4-54759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brandt, S.
A1 - Brozowski, F.
A1 - Horn, Wolfgang
A1 - Plehn, W.
A1 - Müller, B.
T1 - New developments in odour testing: Adapter connects emission test chamber and funnel
N2 - Healthy and energy efficient buildings must be free from disturbing odours. Odour emissions from building materials can be measured with the well-known and accepted standard ISO 16000-28 “Indoor air – Part 28: Determination of odour emissions from building products using test chambers”. For commonly used emission test chambers the sample air is collected in containers (bags) and presented to a group of panel members for the purpose of evaluating the odour. A standard sets requirements for the on-demand presentation in detail. These include the validation procedure for container materials, pre-treatment of bags, details on storage of filled bags and how to carry out the measurements. However, although these measures are proven in practice, incorrect measurements are still possible. Also errors can occur due to a very complex measurement procedure. So, there is a great need for research into how the odour samples are presented.
The proposal planned to be presented will introduce a new development in sample provision by using an adapter which enables collection and provision of sample air without storage or transport of bags. The adapter is a sample container which is permanently positioned on the emission test chamber´s outlet and continuously filled with sample air flowing through it. The flow is briefly interrupted at the time when a sample is taken by a panel member for the test.
The size of the container is sufficient to provide enough sample air for evaluation by at least one panel member via a funnel. Since sampling and presentation are technically connected, it means you can almost do away with storage or transportation and thus it can be presented almost unchanged to the panelmembers. The aim is to reduce measurement errors in the odour samples provision process and the improvement of measurement reproducibility. The paper presents the construction of the adapter as well as the results of emission and odour tests carried out so far.
T2 - CLIMA 2022 The 14th REHVA HVAC World Congress
CY - Rotterdam, The Netherlands
DA - 22.05.2022
KW - Perceived Intensity
KW - Emissionen
KW - Geruch
KW - Bauprodukte
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556192
DO - https://doi.org/10.34641/clima.2022.168
SP - 1
EP - 5
PB - TU Delft open
CY - Delft, Niederlande
AN - OPUS4-55619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brandt, S.
A1 - Brozowski, F.
A1 - Horn, Wolfgang
A1 - Müller, B.
T1 - Odour testing of building products: Examinations for an on-going development of the test standard ISO 16000-28
N2 - VOC-emissions and their odours from building products and furnishings present indoors should not have an impact on personal well-being or health. Odours can be measured by applying the standard ISO 16000-28. Indoor air determination of odour emissions from building products using test chambers. One of the described procedures is the assessment of perceived intensity using a comparative scale by a group of panellists. In this paper, the perceived intensity sampling procedure and its evaluation method are investigated and shown to need improvement. New technical developments in the methodology used to increase the reproducibility of measurement results are discussed. Since odour tests are used for labelling, they have a major influence on the assessment of construction products, similar to the procedure of the German Committee for Health Evaluation of Building Products (AgBB). In the original ISO standard, the evaluation is typically performed using a sampling container separated from the emission chamber. For a better sample presentation, an adapter was developed to connect the emission test chamber to the evaluation funnel and thus enable an odour assessment which is comparable to a direct measurement. The investigations show that losses of odourous substances can be greatly reduced, which is very desirable when seeking to obtain reliable results in odour measurement. Another experimental series was carried out to reduce the measurement effort in the evaluation of perceived intensity. Application of the developed greater than or less than/equal to. query could be helpful here. The results show that the query mostly leads to the same result as the evaluation of the perceived intensity using the method according to the standard but is much easier to perform. Overall, the results can contribute to improving the acceptance of the evaluation of perceived intensity using ISO 16000-28 and to determining odours from building materials increasingly more precisely.
T2 - Healthy Buildings 2023 Europe
CY - Aachen, Germany
DA - 11.06.2023
KW - Building material
KW - Odour
KW - Perceived intensity
KW - VOC
KW - Emission test chamber
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580070
SP - 345
EP - 352
PB - ISIAQ (International Society of Indoor Air Quality and Climate)
CY - Herndon, VA, USA
AN - OPUS4-58007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheuschner, Nils
A1 - Oster, Simon
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Comparison of NIR and SWIR thermography for defect detection in Laser Powder Bed Fusion
N2 - Since laser powder bed fusion (PBF-LB/M) is prone to the formation of defects during the building process, a fundamental requirement for widespread application is to find ways to assure safety and reliability of the additively manufactured parts. A possible solution for this problem lies in the usage of in-situ thermographic monitoring for defect detection. In this contribution we investigate possibilities and limitations of the VIS/NIR wavelength range for defect detection. A VIS/NIR camera can be based on conventional silicon-based sensors which typically have much higher spatial and temporal resolution in the same price range but are more limited in the detectable temperature range than infrared sensors designed for longer wavelengths. To investigate the influence, we compared the thermographic signatures during the creation of artificially provoked defects by local parameter variations in test specimens made of a nickel alloy (UNS N07208) for two different wavelength ranges (~980 nm and ~1600 nm).
KW - Laser powder bed fusion
KW - PBF-LB/M
KW - Thermography
KW - Additive manufacturing
KW - NDT
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610380
DO - https://doi.org/10.1016/j.procir.2024.08.122
VL - 124
SP - 301
EP - 304
PB - Elsevier B.V.
AN - OPUS4-61038
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudry, Mohsin Ali
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Experimental and numerical comparison of heat accumulation during laser powder bed fusion of 316L stainless steel
N2 - Heat accumulation during laser powder bed fusion (LPBF) of metallic build parts can adversely affect their microstructure and mechanical properties. To study the heat accumulation during 316L steel based parts manufactured by LPBF, a finite element method (FEM) based numerical study is carried out. For the investigation, a computationally efficient FEM based model, where the whole layer is simultaneously exposed to a heat source, is used. The simulation results are compared with experimental results to validate the numerical model. While considering different influencing factors such as volumetric energy density (VED) and inter-layer time (ILT), the FEM model is shown to successfully simulate the process of heat accumulation during LPBF based manufacturing of a cuboidal shaped geometry. It is shown that ILT and VED have a significant effect on heat accumulation. The validated numerical model provides a good basis for the optimization of processing parameters and geometries for a future investigation of a reduction of heat accumulation effects. Furthermore, it can be used to quickly provide preheating boundary conditions for detailed investigations by different model approaches at a finer scale for future studies.
KW - Laser powder bed fusion
KW - Finite element method
KW - Heat accumulation
KW - Inter-layer time
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545115
DO - https://doi.org/10.1007/s40964-022-00282-x
SP - 1
EP - 13
PB - Springer
AN - OPUS4-54511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kemmler, Samuel
A1 - Cuéllar, Pablo
A1 - Artinov, Antoni
A1 - Luu, Li-Hua
A1 - Farhat, Abbas
A1 - Philippe, Pierre
A1 - Rettinger, Christoph
A1 - Köstler, Harald
T1 - A fully-resolved micromechanical simulation of piping erosion during a suction bucket installation
N2 - Granular fluidization phenomena such as piping erosion represent a challenge to the delicate installation process of offshore suction bucket foundations. A detailed analysis of the complex conditions in terms of soil composition, soil state, and foundation installation parameters that may lead to piping can be very demanding, if at all possible, solely by experimental means or using macroscopic continuum-based seabed models. The present paper presents a fully-resolved fluid-coupled micromechanical approach for a three-dimensional numerical simulation of the installation process of a suction bucket using the lattice Boltzmann method and discrete element method. The developed model is validated using well-established benchmarks and calibrated by means of experimental data from physical model tests on relevant scenarios focusing on the local fluidization of fixed embedded suction buckets as well as on the suction-driven installation of unrestrained buckets. The qualitative and quantitative agreement with the experimental data both endorse the proposed methodology and highlight the physical soundness of the obtained results. Thereby, the paper shows that three-dimensional analyses of relevant local scenarios at a real scale with little macromechanical model assumptions are feasible.
KW - Micromechanical simulation
KW - Fluid–solid coupling
KW - Piping erosion
KW - Suction bucket foundation
KW - Offshore wind support structure
KW - High-performance computing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633790
DO - https://doi.org/10.1016/j.compgeo.2025.107375
SN - 0266-352X
VL - 186
SP - 1
EP - 17
PB - Elsevier B.V.
AN - OPUS4-63379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rappsilber, Tim
A1 - Krüger, Simone
A1 - Raspe, Tina
A1 - Wagner, Patrick
A1 - Liebner, Christian
A1 - Strzyz, Thaddeus
A1 - Tschirschwitz, Rico
T1 - Hazard classification of different lithium-ion battery types after triggering thermal runaway
N2 - For a better understanding of relevant parameters influencing the thermal runaway, this work classifies the behavior of six different types of lithium-ion batteries. Based on 145 repeatable tests, this research has created a unique and detailed database of battery behavior during thermal runaway. It contains information about changes in cell temperature, voltage, mass loss, smoke gas release and gas pressure. When it comes to characterizing the thermal runaway behavior across different cell types, this work eliminates the need for complex meta-analyses, which can only provide limited information due to the different test conditions in different test benches. In a pressure-resistant 100 dm³ autoclave and an 8-m³ room with connected multi gas analysis, 24 setups were examined under identical conditions. The investigations were carried out as a function of the variation parameters cell geometry, cathode active material, state of charge and initiation method of thermal runaway. The analysis of the measurement data reveals clear differences in the thermal runaway behavior of the tested cell types and can be used as a reference for determining the hazard potential in individual assessment categories of different cells.
All measured values from both test benches as well as the visual evaluation of the cell behavior during the test runs in the 8 m³ room are made available in a comprehensive data table in the supplementary material.
KW - Lithium Ion
KW - Thermal Runaway
KW - State of charge
KW - Hazard classification
KW - gas emission
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634429
DO - https://doi.org/10.1016/j.jlp.2025.105691
SN - 0950-4230
VL - 97
SP - 1
EP - 15
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-63442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Xinyue
A1 - Dong, Ximan
A1 - Zhang, Chuyan
A1 - Zhu, Meng
A1 - Ahmed, Essraa
A1 - Krishnamurthy, Giridharan
A1 - Rouzbahani, Rozita
A1 - Pobedinskas, Paulius
A1 - Gauquelin, Nicolas
A1 - Jannis, Daen
A1 - Kaur, Kawaljit
A1 - Hafez, Aly Mohamed Elsayed
A1 - Thiel, Felix
A1 - Bornemann, Rainer
A1 - Engelhard, Carsten
A1 - Schönherr, Holger
A1 - Verbeeck, Johan
A1 - Haenen, Ken
A1 - Jiang, Xin
A1 - Yang, Nianjun
T1 - Interlayer Affected Diamond Electrochemistry
N2 - Diamond electrochemistry is primarily influenced by quantities of sp3‐carbon, surface terminations, and crystalline structure. In this work, a new dimension is introduced by investigating the effect of using substrate‐interlayers for diamond growth. Boron and nitrogen co‐doped nanocrystalline diamond (BNDD) films are grown on Si substrate without and with Ti and Ta as interlayers, named BNDD/Si, BNDD/Ti/Si, and BNDD/Ta/Ti/Si, respectively. After detailed characterization using microscopies, spectroscopies, electrochemical techniques, and density functional theory simulations, the relationship of composition, interfacial structure, charge transport, and electrochemical properties of the interface between diamond and metal is investigated. The BNDD/Ta/Ti/Si electrodes exhibit faster electron transfer processes than the other two diamond electrodes. The interlayer thus determines the intrinsic activity and reaction kinetics. The reduction in their barrier widths can be attributed to the formation of TaC, which facilitates carrier tunneling, and simultaneously increases the concentration of electrically active defects. As a case study, the BNDD/Ta/Ti/Si electrode is further employed to assemble a redox‐electrolyte‐based supercapacitor device with enhanced performance. In summary, the study not only sheds light on the intricate relationship between interlayer composition, charge transfer, and electrochemical performance but also demonstrates the potential of tailored interlayer design to unlock new capabilities in diamond‐based electrochemical devices.
KW - Nanocrystalline diamond
KW - Interfaces
KW - Electrochemistry
KW - TOF-SIMS
KW - SEM
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621576
DO - https://doi.org/10.1002/smtd.202301774
SN - 2366-9608
VL - 9
IS - 2
SP - 1
EP - 10
PB - Wiley VHC-Verlag
CY - Weinheim
AN - OPUS4-62157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Taparli, Ugur Alp
A1 - Kannengießer, Thomas
A1 - Griesche, Axel
T1 - Tungsten inert gas bead-on-plate weld chemical composition analysis by laser-induced breakdown spectroscopy
N2 - Chemical compositions of a weld can be varying locally as a result of the welding process. These local variations can be due to the vaporization of individual alloying elements. In this work, tungsten inert gas (TIG) bead-on-plate stainless steel welds of EN grade 1.4404 and 1.4435 were investigated using laser-induced breakdown spectroscopy (LIBS) on the completed welds. This study aims to reveal the welding parameters’ influence on the resulting local chemical compositions of the stainless steel welds. We demonstrated Mn vaporize before Cr due to its lower latent enthalpy of vaporization. Hence, Mn accumulates on the heat-affected zone (HAZ) both sides across the weld bead by being swept away through the circulation flow of the welding plasma. Additionally, increasing the heat input tends to enhance the accumulated Mn content on the HAZ as well as increasing the shielding gas flow rate. The results are in good agreement with the literature and proved that LIBS is an effective method to inspect completed welds.
T2 - Symposium on Materials and Joining Technology
CY - Magdeburg, Germany
DA - 07.09.2020
KW - LIBS TIG welding
KW - Austenitic stainless steels
KW - Chemical composition
KW - In situ measurement
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511595
DO - https://doi.org/10.1088/1757-899X/882/1/012023
SN - 1757-8981
SN - 1757-899X
VL - 882
IS - 012023
SP - 1
EP - 8
PB - IOP Publishing
CY - Bristol
AN - OPUS4-51159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Rhode, Michael
A1 - Wimpory, R. C.
A1 - Kannengießer, Thomas
T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part III - Assessment of residual stresses from small-scale to real component welds
N2 - For higher operational temperatures and pressures required in petrochemical plants, the modified 13CrMoV9-10 steel was developed providing high resistance against creep and compressed hydrogen. Extreme care during the welding procedure is necessary for this steel, attributed to low toughness, high strength in as-welded state, and increased susceptibility to stress relief cracking (SRC) during post-weld heat treatment (PWHT). Previous research of SRC in creep-resistant steels discussed mainly thermal and metallurgical factors. Few previous findings addressed the influences of welding procedure on crack formation during PWHT considering real-life manufacturing conditions. These investigations focus on effects of welding heat control on stresses during welding and subsequent PWHT operations close to realistic restraint and heat dissipation conditions using a special 3D testing facility, which was presented in parts I and II of this contribution. Part III addresses investigations on residual stress evolution affecting crack formation and discusses the transferability of results from large-scale testing to laboratory-scale. Experiments with test set-ups at different scales under diverse rigidity conditions and an assessment of the residual stresses of the weld-specimens using X-ray (surface near) and neutron diffraction analysis (bulk) were performed. This study aims to provide a way of investigating the SRC behaviour considering component-specific residual stresses via small-scale testing concepts instead of expensive weld mock-ups.
KW - Welding
KW - Creep-resistant steel
KW - Residual stresses
KW - Post-weld heat treatment
KW - Stress relief cracking
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524403
DO - https://doi.org/10.1007/s40194-021-01101-7
SN - 1878-6669
VL - 65
SP - 1671
EP - 1685
PB - Springer
CY - Berlin
AN - OPUS4-52440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Treutler, K.
A1 - Börner, Andreas
A1 - Gustus, R.
A1 - Kannengießer, Thomas
A1 - Wesling, V.
A1 - Maus-Friedrichs, W.
T1 - Surface finishing of hard-to-machine cladding alloys for highly stressed components
N2 - The supply and processing of materials for highly stressed components are usually cost-intensive. Efforts to achieve cost and resource efficiency lead to more complex structures and contours. Additive manufacturing steps for component repair and production offer significant economic advantages. Machining needs to be coordinated with additive manufacturing steps in a complementary way to produce functional surfaces suitable for the demands. Regarding inhomogeneity and anisotropy of the microstructure and properties as well as production-related stresses, a great deal of knowledge is still required for efficient use by small- and medium-size enterprises, especially for the interactions of subsequent machining of these difficult-to-machine materials. Therefore, investigations on these influences and interactions were carried out using a highly innovative cost-intensive NiCrMo alloy (IN725). These alloys are applied for claddings as well as for additive component manufacturing and repair welding using gas metal arc welding processes. For the welded specimens, the adequate solidification morphology, microstructure and property profile were investigated. The machinability in terms of finishing milling of the welded surfaces and comparative analyses for ultrasonic-assisted milling processes was examined focussing on surface integrity. It was shown that appropriate cutting parameters and superimposed oscillating of the milling tool in the direction of the tool rotation significantly reduce the mechanical loads for tool and workpiece surface. This contributes to ensure a high surface integrity, especially when cutting has to be carried out without cooling lubricants.
KW - WAAM
KW - IN725
KW - Machining
KW - Ultrasonic-assisted milling
KW - Residual stresses
KW - Cutting forces
KW - Surface integrity
KW - Microstructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524872
DO - https://doi.org/10.1007/s00170-021-06815-y
VL - 114
IS - 5-6
SP - 1427
EP - 1442
PB - Springer
AN - OPUS4-52487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Wandtke, Karsten
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Process-related influences and correlations in wire arc additive manufacturing of high-strength steels
N2 - High-strength fine-grained structural steels have great potential for weight-optimized, efficient structures in many modern steel applications. Further advances in efficiency can be achieved through additive manufacturing and bionic design. Commercial high-strength filler materials for wire arc additive manufacturing (WAAM) are already provided by the consumable producers. Today, application would be strictly limited due to absence of quantitative findings or any guidelines for the industry regarding welding-related stresses and component safety during manufacturing and service. Hence, process- and material-related influences and design-related restraint conditions associated with formation of residual stresses and cold cracking risk are investigated. The aim is the accessibility of special WAAM self-restraining cold cracking tests and easy applicable processing recommendations, enabling an economical, fit-for-purpose and crack-safe WAAM of high-strength steels. This first study focuses on determination of interactions between WAAM process parameters, resulting layer geometry, microstructure and residual stresses, analyzed via X-ray diffraction. Defined reference specimens are automated welded using a special WAAM solid wire (yield strength >820 MPa). Geometric properties can be specifically adjusted by wire feed and welding speed, but cannot be varied arbitrarily, since a high heat input causes local overheating, inadmissible changes of microstructure and mechanical properties, defects and comparable high tensile residual stresses.
T2 - 22. Werkstofftechnischen Kolloquium der TU Chemnitz
CY - Online meeting
DA - 24.03.2021
KW - Residual stresses
KW - Additive Manufacturing
KW - High-strength steel
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533300
DO - https://doi.org/10.1088/1757-899X/1147/1/012002
VL - 1147
SP - 012002
PB - IOP Publishing Ltd
AN - OPUS4-53330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Mente, Tobias
A1 - Richter, Tim
A1 - Kannengießer, Thomas
T1 - Characterization of Hydrogen Diffusion in Offshore Steel S420G2+M Multi-layer Submerged Arc Welded Joint
N2 - As onshore installation capacity is limited, the increase in the number of offshore wind turbines (OWT) is a major goal. In that connection, the OWTs continuously increase in size and weight and demand adequate foundations concepts like monopiles or tripods. These components are typically manufactured from welded mild steel plates with thickness up to 200 mm. The predominant welding technique is submerged arc welding (SAW). In accordance with the standards, the occurrence of hydrogen-assisted cracking is anticipated by either a minimum waiting time (MWT, before non-destructive testing of the welded joint is allowed) at ambient or a hydrogen removal heat treatment (HRHT) at elevated temperatures. The effectiveness of both can be estimated by calculation of the diffusion time, i.e., diffusion coefficients. In this study, these coefficients are obtained for the first time for a thick-walled S420G2+M offshore steel grade and its multi-layer SAW joint. The electrochemical permeation technique at ambient temperature is used for the determination of diffusion coefficients for both the base material and the weld metal. The coefficients are within a range of 1025 to 1024 mm2/s (whereas the weld metal had the lowest) and are used for an analytical and numerical calculation of the hydrogen diffusion and the related MWT. The results showed that long MWT can occur, which would be necessary to significantly decrease the hydrogen concentration. Weld metal diffusion coefficients at elevated temperatures were calculated from hydrogen desorption experiments by carrier gas hot extraction. They are within a range of 1023 mm2/s and used for the characterization of a HRHT dwell-time. The analytical calculation shows the same tendency of long necessary times also at elevated temperatures. That means the necessary time is strongly influenced by the considered plate thickness and the estimation of any MWT/HRHT via diffusion coefficients should be critically discussed.
T2 - European Congress and Exhibition on Advanced Materials and Process - Euromat 2021
CY - Online meeting
DA - 13.09.2021
KW - Thick-walled
KW - Hydrogen diffusion
KW - Offshore
KW - Steel
KW - Submerged arc welding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544127
DO - https://doi.org/10.1007/s11665-022-06679-7
SN - 1059-9495
SP - 1
EP - 13
PB - Springer Nature
AN - OPUS4-54412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
T1 - In situ investigation of chemical composition during TIG welding in duplex stainless steels using Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - Many applications in industry require a material-to-material joining process of Duplex Stainless Steels (DSS). Therefore, it is essential to investigate the material’s properties during a welding process to control the weld quality. With the help of Laser-Induced Breakdown Spectroscopy (LIBS), the chemical composition during the Tungsten Inert Gas (TIG) welding process of DSS could be monitored in situ. The chemical composition could be quantitatively measured using pre-established calibration curves. Although the surface temperature and the welding plasma have a high influence on the spectral intensities, reliable composition measurements were possible. The concentration of alloying elements could be mapped during the TIG welding process.
T2 - 2nd International Conference on Advanced Joining Processes
CY - Sintra, Portugal
DA - 21.10.2021
KW - LIBS
KW - In situ measurement
KW - WRC 1992 diagram
KW - TIG welding
KW - Duplex stainless steels
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542026
DO - https://doi.org/10.1016/j.finmec.2021.100063
SN - 2666-3597
VL - 6
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Thomas, Maximilian
A1 - Kannengießer, Thomas
A1 - Gibmeier, J.
A1 - Vollert, F.
T1 - Assessment of the Solidification Cracking Susceptibility of Welding Consumables in the Varestraint Test by Means of an Extended Evaluation Methodology
N2 - Various test methods are available for assessing the susceptibility of materials to solidification cracking during welding. In the widely used Varestraint test, the crack length is selected as a criterion as a function of the applied bending strain.
Unfortunately, the crack length does not characterize the material behavior alone but depends to varying degrees on the individual test parameters used, which makes the interpretation of the results difficult. In addition, the crack length is not comparable under different test conditions. To overcome these disadvantages, we have developed a novel evaluation methodology that decouples the machine influence from the material behavior. The measured crack length is related to the maximum possible value specified by welding speed and deformation time. This relative crack length is calculated numerically, considering the orientation of the cracks. Experiments on two high-alloy martensitic welding consumables show that, in contrast to the conventional evaluation, a comparison of different welding parameters becomes possible. Furthermore, the strain rate proved to be a suitable crack criterion in agreement with Prokhorov's hot cracking model.
KW - Welding
KW - Solidification cracking
KW - Varestraint test
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545780
DO - https://doi.org/10.1002/adem.202101650
SN - 1438-1656
SP - 2101650
PB - Wiley online library
AN - OPUS4-54578
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Czeskleba, Denis
A1 - Fleißner-Rieger, H.
A1 - Nietzke, Jonathan
A1 - Kannengießer, Thomas
T1 - Combined heating rate and restraint condition effect on stress relief cracking during PWHT of thick-walled Cr–Mo-V steel SAW joints
N2 - Creep-resistant steels such as 13CrMoV9-10 are utilized in the manufacture of thick-walled pressure vessels and are typically joined by submerged arc welding (SAW). However, these materials are susceptible to stress relief cracking (SRC) if the required post weld heat treatment (PWHT) is not applied correctly. Existing PWHT guidelines, encompassing heating rate and dwell (or holding) time at a given temperature, are derived from a synthesis of empirical knowledge and typically free-shrinkage weld experiments to assess the susceptibility to SRC. Therefore, this study discusses the combined effect of the PWHT heating rate under free-shrinkage compared to restrained shrinkage. Welding experiments were conducted (using plates with a thickness of 25 mm) for both shrinkage conditions for a variety of heating rates and maximum temperatures. In-situ acoustic emission analysis was used to locate propagating SRCs during PWHT. Hardness measurements, mechanical property characterization (Charpy impact strength), and microstructure correlation were used to evaluate the SRC susceptibility. The results suggested that the influence of heating rate could not be directly related to SRC formation and that the initial weld microstructure prior to PWHT was more relevant in terms of very high hardness in the coarse grain heat affected zone, especially that of the last beads in the top layer of the welding sequence. This was seen in the form of random, unexpected SRC occurrence in only one specimen at a heating rate commonly used in welding practice (approximately 100 K/h). In this context, the additional effect of an external shrinkage restraint on SRC must be considered in the form of increasing mechanical loads during welding, which are typically not within the scope of welding practice. To mitigate the probability of SRC during PWHT, it is imperative to reduce the welding heat input and to restrict the structural shrinkage restraint of the weld joint.
KW - Component test
KW - Stress relief cracking
KW - PWHT
KW - Creep-resistant steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631439
DO - https://doi.org/10.1007/s40194-025-02062-x
SN - 1878-6669
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-63143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liepold, Philipp
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Investigation of restraint intensity influence on solidification cracking of high-strength filler materials in fillet welds via CTS testing
N2 - In addition to chemical composition, metallurgy, and welding parameters, the intensity of restraint is one of the key variables influencing solidification cracking (SC). Due to their high strength-to-density ratio, many modern lightweight steel constructions increasingly rely on high-strength steel. Given the theoretical framework of solidification cracking theory, tests tend to focus on the effects of strain rate. Externally restrained tests have provided valuable insights into solidification crack susceptibility. In practice, most welded structures are self-restrained; therefore, self-restraint tests more accurately reflect real-world applications. By varying the plate thickness in controlled thermal severity (CTS) tests conducted on S1100 QL, it was possible to adjust the intensity of restraint on fillet welds at a high level. Testing was performed using four different filler wires for gas metal arc welding (GMAW), including three solid wires and one metal-cored wire. Additionally, two sets of welding parameters were evaluated. High arc energy (U × I/welding speed) and increased welding speed were found to be more prone to solidification cracking compared to the parameter set with lower arc energy and welding speed. The results indicate a correlation between increasing restraint severity and a higher incidence of solidification cracking.
KW - CTS
KW - Controlled thermal severity
KW - High-strength steel
KW - GMAW
KW - Restraint
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631315
UR - 1878-6669
DO - https://doi.org/10.1007/s40194-025-02046-x
SP - 1
EP - 13
PB - Springer
AN - OPUS4-63131
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hübner, Martin
A1 - Dittmann, Florian
A1 - Kromm, Arne
A1 - Varfolomeev, Igor
A1 - Kannengießer, Thomas
T1 - Residual stress reduction using a low transformation temperature welding consumable with focus on the weld geometry
N2 - Low transformation temperature (LTT) welding consumables represent an innovative approach to realize compressive residual stress in the weld seam and HAZ. LTT welding consumables use the volume-expanding martensitic phase transformation near room temperature to generate compressive residual stress during cooling. This article focuses on the weld geometry and its influence on residual stress reduction using an LTT welding consumable. For this purpose, layers with an LTT welding consumable were additionally applied to the front sides of conventionally welded longitudinal stiffeners. Different weld geometries of the second weld seam could be realized by varying the welding parameters. These samples were analyzed for geometric parameters, chemical composition, and residual stress. While the chemical composition and martensite start temperature (MS) were only slightly influenced by parameter changes, a clear influence with regard to residual stress and weld geometry was observed. Depending on the shape of the second LTT weld seam, residual stress reductions of 200 to 500 MPa were achieved using the same LTT welding consumable.
T2 - IIW Annual Assembly and International Conference
CY - Rhodes Island, Dodecanisa, Greece
DA - 07.07.2024
KW - Low transformation temperature (LTT)
KW - Martensite start temperature
KW - Dilution
KW - Weld geometry
KW - Residual stress
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633707
DO - https://doi.org/10.1007/s40194-025-02094-3
SN - 1878-6669
SP - 1
EP - 11
PB - Springer Nature
CY - Berlin ; Heidelberg
AN - OPUS4-63370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engelking, Lorenz
A1 - Scharf-Wildenhain, R.
A1 - Schröpfer, Dirk
A1 - Hälsig, A.
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Influence of heat input on properties and residual stresses in hybrid addi-tive manufacturing of high strength steels using MSG processes
N2 - The application of steels with a higher yield strength allows reductions in wall thickness, component weight and production costs. Hybrid additive manufacturing based on Gas Metal Arc Welding (GMAW) processes (DED-Arc) can be used to realise highly effi-cient component modifications and repairs on semi-finished products and additively manufactured structures. There are still a number of key issues preventing widespread implementation, particularly for SMEs. In addition to the manufacturing design, detailed information about assembly strategy and geometric adaptation of the component for modifications or repairs are missing. These include the welding-related stresses associ-ated with the microstructural influences caused by the additive manufacturing steps, particularly in the transition area of the substrate and filler material interface. The pre-sent research focuses the effect of welding heat control during DED-Arc process on the residual stresses, especially in the transition area. Defined specimens were welded fully automatically with a high-strength solid wire (yield strength > 790 MPa) especially adapted for DED-Arc on S690QL substrate. The working temperature and heat input were systematically varied for a statistical effect analysis on the residual stress state of the hybrid manufactured components. Regarding heat control, t8/5 cooling times within the recommended processing range (approx. 5 s to 20 s) were complied. The investiga-tion revealed a significant influence of the working temperature Ti on the compressive residual stresses in the transition area and the tensile residual stresses at the base of the substrate. High working temperatures result in lower compressive residual stresses, heat input E does not significantly affect the tensile stresses.
T2 - 6. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632188
DO - https://doi.org/10.21268/20250506-3
SP - 110
EP - 122
AN - OPUS4-63218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Breese, Philipp Peter
A1 - Metz, Christian
A1 - Altenburg, Simon
T1 - In-situ monitoring for PBF-LB/M processes: Does multispectral optical tomography add value in recognizing process deviations?
N2 - Laser powder bed fusion of metallic components (PBF-LB/M) is gaining acceptance in industry. However, the high costs and lengthy qualification processes required for printed components create the need for more effective in-situ monitoring and testing methods. This article proposes multispectral Optical Tomography (OT) as a new approach for monitoring the PBF-LB/M process. Compared to other methods, OT is a low-cost process monitoring method that uses long-time exposure imaging to observe the build process. However, it lacks time resolution compared to expensive thermographic sensor systems. Monochromatic OT (1C-OT) is already commercially available and observes the building process layer-wise using a single wavelength window in the NIR range. Multispectral OT (nC-OT) utilizes a similar setup but can measure multiple wavelength ranges per location simultaneously. By comparing the classical 1C-OT and nC-OT approaches, this article examines the advantages of nC-OT (two channel OT and RGB-OT) in reducing the false positive rate for process deviations and approximating maximum temperatures for a better comparison between different build processes and materials. This could ultimately reduce costs and time for part qualification. The main goal of this contribution is to assess the advantages of nC-OT compared to 1C-OT for in-situ process monitoring of PBF-LB/M.
T2 - Nolamp 2023
CY - Turku, Finland
DA - 22.08.2023
KW - Thermography
KW - Process Monitoring
KW - Additive manufacturing
KW - BPF-LB/M
KW - In-situ
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592498
DO - https://doi.org/10.1088/1757-899X/1296/1/012008
VL - 1296
SP - 1
EP - 11
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-59249
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Altenburg, Simon
A1 - Scheuschner, Nils
A1 - Breese, Philipp Peter
A1 - Metz, C.
A1 - Hilgenberg, Kai
A1 - Maierhofer, Christiane
T1 - In-situ monitoring of the Laser Powder Bed Fusion build process via bi- chromatic optical tomography
N2 - As metal additive manufacturing (AM) is entering industrial serial production of safety relevant components, the need for reliable process qualification is growing continuously. Especially in strictly regulated industries, such as aviation, the use of AM is strongly dependent on ensuring consistent quality of components. Because of its numerous influencing factors, up to now, the metal AM process is not fully controllable. Today, expensive part qualification processes for each single component are common in industry.
This contribution focusses on bi-chromatic optical tomography as a new approach for AM in-situ quality control. In contrast to classical optical tomography, the emitted process radiation is monitored simultaneously with two temperature calibrated cameras at two separate wavelength bands. This approach allows one to estimate the local maximum temperatures during the manufacturing process, thus increases the comparability of monitoring data of different processes. A new process information level at low investment cost is reachable, compared to, e.g., infrared thermography.
T2 - LANE 2022
CY - Fürth, Germany
DA - 04.08.2022
KW - Optical tomography
KW - Additive Manufacturing
KW - L-PBF
KW - In-process monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560270
DO - https://doi.org/10.1016/j.procir.2022.08.035
SN - 2212-8271
VL - 111
SP - 340
EP - 344
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-56027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Oster, Simon
A1 - Metz, C.
A1 - Altenburg, Simon
T1 - In-situ defect detection via active laser thermographic testing for PBF-LB/M
N2 - Great complexity characterizes Additive Manufacturing (AM) of metallic components via laser powder bed fusion (PBF-LB/M). Due to this, defects in the printed components (like cracks and pores) are still common. Monitoring methods are commercially used, but the relationship between process data and defect formation is not well understood yet. Furthermore, defects and deformations might develop with a temporal delay to the laser energy input. The component’s actual quality is consequently only determinable after the finished process.
To overcome this drawback, thermographic in-situ testing is introduced. The defocused process laser is utilized for nondestructive testing performed layer by layer throughout the build process. The results of the defect detection via infrared cameras are shown for a research PBF-LB/M machine.
This creates the basis for a shift from in-situ monitoring towards in-situ testing during the AM process. Defects are detected immediately inside the process chamber, and the actual component quality is determined.
T2 - Lasers in Manufacturing (LiM)
CY - Munich, Germany
DA - 26.06.2023
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Nondestructive testing
KW - Laser thermography
KW - Defect detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585060
SP - 1
EP - 10
PB - Wissenschaftliche Gesellschaft Lasertechnik und Photonik (WLT)
CY - Hannover
AN - OPUS4-58506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Tina
A1 - Stark, T.
A1 - Arduini, M.
A1 - Manara, J.
A1 - Altenburg, Simon
T1 - Knowing the spectral directional emissivity of 316L and AlSi10Mg PBF-LB/M surfaces: Gamechanger for quantitative in situ monitoring
N2 - For a deep process understanding of the laser powder bed fusion process (PBF-LB/M), recording of the occurring surface temperatures is of utmost interest and would help to pave the way for reliable process monitoring and quality assurance. A notable number of approaches for in-process monitoring of the PBF-LB/M process focus on the monitoring of thermal process signatures. However, due to the elaborate calibration effort and the lack of knowledge about the occurring spectral directional emissivity, only a few approaches attempt to measure real temperatures. In this study, to gain initial insights into occurring in the PBF-LB/M process, measurements on PBF-LB/M specimens and metal powder specimens were performed for higher temperatures up to T = 1290 °C by means of the emissivity measurement apparatus (EMMA) of the Center for Applied Energy Research (CAE, Wuerzburg, Germany). Also, measurements at ambient temperatures were performed with a suitable measurement setup. Two different materials—stainless steel 316L and aluminum AlSi10Mg—were examined. The investigated wavelength λ ranges from the visible range (λ-VIS= 0.40–0.75 µm) up to the infrared, λ = 20 µm. The influence of the following factors were investigated: azimuth angle φ, specimen temperature TS, surface texture as for PBF-LB/M surfaces with different scan angles α, and powder surfaces with different layer thicknesses t.
T2 - Rapid.Tech 3D 2024
CY - Erfurt, Germany
DA - 14.05.2024
KW - PBF-LB/M
KW - In situ monitoring
KW - Emissivity
KW - Additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601471
DO - https://doi.org/10.1007/s40964-024-00665-2
SN - 2363-9520
SP - 1
EP - 10
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-60147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breese, Philipp Peter
A1 - Altenburg, Simon
T1 - Absolute temperature determination in laser powder bed fusion (PBF-LB/M) via hyperspectral thermography
N2 - Temperature is a key characteristic in laser powder bed fusion of metals (PBF-LB/M). As a quantitative physical property, the temperature can determine the actual process quality independently from the nominal process parameters. Thus, establishing a process evaluation on temperatures rather than the comparison of process conditions is expected to be more effective. However, quantitative in situ temperature measurements with classical thermographic methods are virtually impossible. The reason is that the required emissivity value changes drastically throughout the process. Additionally, large temperature ranges along with the highly dynamic nature of the PBF-LB/M process make temperature measurements difficult. Based on this challenge, this work presents a method for hyperspectral temperature determination. The spectral exitance (in W/m2⋅nm) was measured in situ at many adjacent wavelengths in the short-wave infrared (SWIR). This enabled a local temperature determination via Planck’s law in combination with a spectral emissivity function. The temperature field of the melt pool crossing the 1D measurement line was reconstructed from the information, gathered at nearly 20 kHz sampling rate. The reconstructed melt pool had a spatial resolution of 17 µm by 40 µm, and temperatures between 2700 and 1300 K were observable. Comparison of the 316L stainless steel solidification temperature and the observed solidification plateau in the gathered thermal data revealed a relative error of less than 6% in the absolute temperature measurement. These initial results of hyperspectral temperature determination in PBF-LB/M show the potential in the method. It allows for physically founded process evaluation, and the prospects for tuning and validation of numerical simulations are highly promising.
KW - Additive Manufacturing
KW - Infrared Thermography
KW - In-situ Monitoring
KW - Quantitative Temperature Measurement
KW - Emissivity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631977
DO - https://doi.org/10.1007/s40964-025-01148-8
SN - 2363-9512
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-63197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Breese, Philipp Peter
A1 - Becker, Tina
A1 - Oster, Simon
A1 - Metz, C.
A1 - Altenburg, Simon
T1 - In-situ defect detection for laser powder bed fusion with active laser thermography
N2 - Defects are still common in metal components built with Additive Manufacturing (AM). Process monitoring methods for laser powder bed fusion (PBF-LB/M) are used in industry, but relationships between monitoring data and defect formation are not fully understood yet. Additionally, defects and deformations may develop with a time delay to the laser energy input. Thus, currently, the component quality is only determinable after the finished process.
Here, active laser thermography, a nondestructive testing method, is adapted to PBF-LB/M, using the defocused process laser as heat source. The testing can be performed layer by layer throughout the manufacturing process. We study our proposed testing method along experiments carried out on a custom research PBF-LB/M machine using infrared (IR) cameras.
Our work enables a shift from post-process testing of components towards in-situ testing during the AM process. The actual component quality is evaluated in the process chamber and defects can be detected between layers.
T2 - 2023 International Solid Freeform Fabrication Symposium
CY - Austin, TX, USA
DA - 14.08.2023
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - Nondestructive Testing
KW - Thermography
KW - Defect Detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606288
DO - https://doi.org/10.26153/tsw/51096
SP - 1978
EP - 1989
PB - University of Texas at Austin
CY - Austin, TX, USA
AN - OPUS4-60628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Breese, Philipp Peter
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Altenburg, Simon
T1 - A deep learning framework for defect prediction based on thermographic in-situmonitoring in laser powder bed fusion
N2 - The prediction of porosity is a crucial task for metal based additive manufacturing techniques such as laser powder bed fusion. Short wave infrared thermography as an in-situ monitoring tool enables the measurement of the surface radiosity during the laser exposure. Based on the thermogram data, the thermal history of the component can be reconstructed which is closely related to the resulting mechanical properties and to the formation of porosity in the part. In this study, we present a novel framework for the local prediction of porosity based on extracted features from thermogram data. The framework consists of a data pre-processing workflow and a supervised deep learning classifier architecture. The data pre-processing
workflow generates samples from thermogram feature data by including feature information from multiple subsequent layers.
Thereby, the prediction of the occurrence of complex process phenomena such as keyhole pores is enabled. A custom convolutional neural network model is used for classification. Themodel is trained and tested on a dataset from thermographic in-situ monitoring of the manufacturing of an AISI 316L stainless steel test component. The impact of the pre-processing parameters and the local void distribution on the classification performance is studied in detail. The presented model achieves an accuracy of 0.96 and an f1-Score of 0.86 for predicting keyhole porosity in small sub-volumes with a dimension of (700 × 700 × 50) μm3. Furthermore, we show that pre-processing parameters such as the porosity threshold for sample
labeling and the number of included subsequent layers are influential for the model performance. Moreover, the model prediction is shown to be sensitive to local porosity changes although it is trained on binary labeled data that disregards the actual sample porosity.
KW - Laser Powder Bed Fusion (PBF-LB/M, L-PBF)
KW - Selective Laser Melting (SLM)
KW - SWIR thermography
KW - Online monitoring
KW - Flaw detection
KW - Machine learning
KW - Convolutional neural networks (CNN)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575148
DO - https://doi.org/10.1007/s10845-023-02117-0
SN - 0956-5515
SP - 1
EP - 20
PB - Springer
AN - OPUS4-57514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Ulbricht, Alexander
A1 - Heinrich, Ph.
A1 - Baum, D.
A1 - Maierhofer, Christiane
A1 - Hilgenberg, Kai
T1 - In-Situ Defect Detection in Laser Powder Bed Fusion by Using Thermography and Optical Tomography—Comparison to Computed Tomography
N2 - Among additive manufacturing (AM) technologies, the laser powder bed fusion (L-PBF) is one of the most important technologies to produce metallic components. The layer-wise build-up of components and the complex process conditions increase the probability of the occurrence of defects. However, due to the iterative nature of its manufacturing process and in contrast to conventional manufacturing technologies such as casting, L-PBF offers unique opportunities for in-situ monitoring. In this study, two cameras were successfully tested simultaneously as a machine manufacturer independent process monitoring setup: a high-frequency infrared camera and a camera for long time exposure, working in the visible and infrared spectrum and equipped with a near infrared filter. An AISI 316L stainless steel specimen with integrated artificial defects has been monitored during the build. The acquired camera data was compared to data obtained by computed tomography. A promising and easy to use examination method for data analysis was developed and correlations between measured signals and defects were identified. Moreover, sources of possible data misinterpretation were specified. Lastly, attempts for automatic data analysis by data Integration are presented.
KW - Laser powder bed fusion (L-PBF)
KW - Selective laser melting (SLM)
KW - Additive manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
KW - Optical tomography
KW - Computed tomography (CT)
KW - Data fusion
KW - Lack-of-fusion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502417
DO - https://doi.org/10.3390/met10010103
VL - 10
IS - 1
SP - 103
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-50241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
T1 - Effects of inter layer time and build height on resulting properties of 316L stainless steel processed by laser powder bed fusion
N2 - Laser powder bed fusion (L-PBF) is the most prominent additive manufacturing (AM) technology for metal part production. Among the high number of factors influencing part quality and mechanical properties, the inter layer time (ILT) between iterative melting of volume elements in subsequent layers is almost completely unappreciated in the relevant literature on L-PBF. This study investigates the effect of ILT with respect to build height and under distinct levels of volumetric energy density (VED) using the example of 316L stainless steel. In-situ thermography is used to gather information on cooling conditions during the process, which is followed by an extensive metallographic analysis. Significant effects of ILT and build height on heat accumulation, sub-grain sizes, melt pool geometries and hardness are presented. Furthermore, the rise of defect densities can be attributed to a mutual interplay of build height and ILT. Hence, ILT has been identified as a crucial factor for L-PBF of real part components especially for those with small cross sections.
KW - Laser powder bed fusion (L-PBF)
KW - Laser beam melting (LBM)
KW - Selective laser melting (SLM)
KW - Dwell-time
KW - Thermography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503300
DO - https://doi.org/10.1016/j.addma.2020.101080
SN - 2214-8604
VL - 32
SP - 101080-1
EP - 101080-13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-50330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Nowakowski, Susanna
A1 - Altenburg, Simon
A1 - Maierhofer, Christiane
A1 - Hilgenberg, Kai
T1 - Experimental Determination of the Emissivity of Powder Layers and Bulk Material in Laser Powder Bed Fusion Using Infrared Thermography and Thermocouples
N2 - Recording the temperature distribution of the layer under construction during laser powder bed fusion (L-PBF) is of utmost interest for a deep process understanding as well as for quality assurance and in situ monitoring means. While having a notable number of thermal monitoring approaches in additive manufacturing (AM), attempts at temperature calibration and emissivity determination are relatively rare. This study aims for the experimental temperature adjustment of an off-axis infrared (IR) thermography setup used for in situ thermal data acquisition in L-PBF processes. The temperature adjustment was conducted by means of the so-called contact method using thermocouples at two different surface conditions and two different materials: AISI 316L L-PBF bulk surface, AISI 316L powder surface, and IN718 powder surface. The apparent emissivity values for the particular setup were determined. For the first time, also corrected, closer to real emissivity values of the bulk or powder surface condition are published. In the temperature region from approximately 150 °C to 580 °C, the corrected emissivity was determined in a range from 0.2 to 0.25 for a 316L L-PBF bulk surface, in a range from 0.37 to 0.45 for 316L powder layer, and in a range from 0.37 to 0.4 for IN718 powder layer.
KW - Emisssivity
KW - Laser Powder Bed Fusion (L-PBF)
KW - Selective Laser Melting (SLM)
KW - Additive Manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516148
DO - https://doi.org/10.3390/met10111546
VL - 10
IS - 11
SP - 1546
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-51614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
T1 - On the limitations of small cubes as test coupons for process parameter optimization in laser powder bed fusion of metals
N2 - The capability to produce complexly and individually shaped metallic parts is one of the main advantages of the laser powder bed fusion (PBF LB/M) process. Development of material and machine specific process parameters is commonly based on results acquired from small cubic test coupons of about 10 mm edge length. Such cubes are usually used to conduct an optimization of process parameters to produce dense material. The parameters are then taken as the basis for the manufacturing of real part geometries. However, complex geometries go along with complex thermal histories during the manufacturing process, which can significantly differ from thermal conditions prevalent during the production of simply shaped test coupons. This may lead to unexpected and unpredicted local inhomogeneities of the microstructure and defect distribution in the final part and it is a root cause of reservations against the use of additive manufacturing for the production of safety relevant parts. In this study, the influence of changing thermal conditions on the resulting melt pool depth of 316L stainless steel specimens is demonstrated. A variation of thermo-graphically measured intrinsic preheating temperatures was triggered by an alteration of inter layer times and a variation of cross section areas of specimens for three distinct sets of process parameters. Correlations between the preheating temperature, the melt pool depth, and occurring defects were analyzed. The limited expressiveness of the results of small density cubes is revealed throughout the systematic investigation. Finally, a clear recommendation to consider thermal conditions in future process parameter optimizations is given.
T2 - Icaleo 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Additive manufacturing
KW - Heat accumulation
KW - Thermal history
KW - In situ monitoring
KW - Representative specimens
KW - Thermography
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586558
DO - https://doi.org/10.2351/7.0001080
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
AN - OPUS4-58655
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Maack, Stefan
T1 - Improving onset picking in ultrasonic testing by using a spectral entropy criterion
N2 - In ultrasonic testing, material and structural properties of a specimen can be derived from the time-of-flight (ToF). Using signal features, such as the first peak or envelope maximum, to calculate the ToF is error-prone in multipath arrangements or dispersive and attenuating materials, which is not the case for the signal onset. Borrowing from seismology, researchers used the Akaike information criterion (AIC) picker to automatically determine onset times. The most commonly used formulation, Maeda's AIC picker, is reassessed and found to be based on inappropriate assumptions for signals often used in ultrasonic testing and dependent on arbitrary parameters. Consequently, an onset picker for ultrasonic through-transmission measurements is proposed, based on a spectral entropy criterion (SEC) to model the signal using the AIC framework. This SEC picker takes into account the spectral properties of the ultrasonic signal and is virtually free of arbitrary parameters. Synthetic and experimental data are used to compare the performance of SEC and AIC pickers. It is shown that the accuracy of onset picking is improved for densely sampled data.
KW - Akaike information criterion picker
KW - Nondestructive testing
KW - Ultrasound
KW - Time of flight
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594284
UR - https://pubs.aip.org/asa/jasa/article/155/1/544/3061576/Improving-onset-picking-in-ultrasonic-testing-by
DO - https://doi.org/10.1121/10.0024337
SN - 0001-4966
VL - 155
IS - 1
SP - 544
EP - 554
PB - AIP Publishing
CY - Melville, NY, USA
AN - OPUS4-59428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästle, Emanuel D.
A1 - Ghaznavi, Ali
A1 - Duffner, Eric
T1 - Failure monitoring and classification from acoustic emission tests on impact-damaged hydrogen composite pressure vessels
N2 - A total of nine heavily damaged carbon-fibre overwrapped pressure vessels are tested. The burst pressure of the damaged vessels correlates with the impact energy and the internal pressure during impact. No internal pressure leads to larger deformation and lower burst pressure. The vessels are tested with acoustic emissions prior to bursting. It can be shown that major instabilities give rise to a significantly increased number of acoustic signals. The location of occurrence corresponds to the impact regions. The signals are studied in terms of their frequency content and it can be shown that high frequency signals experience strong damping so that there are only few recorded high-frequency events and even fewer that are locatable. The data is further used in a cluster analysis to assign the signals to different failure types. With the given experimental design, no clear patterns emerge so that the failure association
remains ambiguous.
KW - Acoustic Emission
KW - Carbon-Fibre Overwrapped Pressure Vessels
KW - Impact Damage
KW - Cluster Analysis
KW - Frequency Features
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613266
DO - https://doi.org/10.58286/30256
SN - 1435-4934
VL - 29
IS - 10
SP - 1
EP - 12
PB - NDT.net GmbH & Co. KG
AN - OPUS4-61326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästle, Emanuel David
A1 - Paffrath, M.
A1 - El‐Sharkawy, A.
T1 - Alpine Crust and Mantle Structure From 3D Monte Carlo Surface‐ and Body‐Wave Tomography
N2 - An ongoing controversy revolves around the detailed structure of the subducting European and Adriatic plates under the Alps and the adjacent orogens. Mostly based on P‐wave travel time tomographic images, slab break‐off at different times, reversals of subduction polarity and segmentation of the slab into independent units have been proposed. These processes may have important geodynamic consequences such as rapid surface uplift, past magmatic events or changes in the style of continental collision. However, some of the tomographic results are contradictory, particularly evident in the uppermost mantle where teleseismic P waves traverse the medium almost vertically with few ray crossings and a stronger dependence on the crustal correction. In this work, we present the result of an innovative joint inversion approach using surface‐ and teleseismic body‐wave travel times to mitigate some of the shortcomings in both data types. Applying a reversible‐jump Markov chain Monte Carlo approach, we simultaneously constrain the and structure and their uncertainties in the crust and upper mantle. The results indicate a continuous slab structure from the crust‐mantle boundary down to at least 400 km depth under the western, central and eastern Alps. The results, however, also suggest that fitting the data within their respective measurement uncertainties may not be sufficient to reliably determine the presence of a shallow slab break‐off beneath the Alps.
KW - Tomographic Imaging
KW - Plate Tectonics
KW - McMC Tomography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626216
DO - https://doi.org/10.1029/2024JB030101
SN - 2169-9356
VL - 130
IS - 2
SP - 1
EP - 29
PB - American Geophysical Union (AGU)
AN - OPUS4-62621
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Romero-Navarrete, José A.
A1 - Otremba, Frank
A1 - Lozano Guzman, A. A.
T1 - Estimation of the effect of the driving style on pollutants emission by heavy trucks
N2 - Different approaches have been attempted so far to reduce fuel consumption and linked pollutants, including vehicle equipment and design, with rational driving style being recognized as a potential source of fuel savings. However, no specific methodology had been suggested so far to assess fuel economy of driving other than the fuel consumed itself. In this paper, the Standard deviation of driving acceleration has been found to be directly associated to fuel consumption, so that the less dispersion of the driving acceleration, produces the lower fuel consumptions and emissions. Such metric could be thus used to assess driving style.
KW - Driving style
KW - Fuel consumption
KW - Stored energy
KW - GPS data
KW - Simulation
KW - Particle emissions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511540
UR - https://www.iaras.org/iaras/home/caijes/estimation-of-the-effect-of-the-driving-style-on-pollutants-emission-by-heavy-trucks
SN - 2367-8941
VL - 5
SP - 220
EP - 226
PB - IARAS
CY - Sofia
AN - OPUS4-51154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Romero-Navarrete, José A.
A1 - Otremba, Frank
T1 - A method to assess the gravity response efficiency of a truck
N2 - In spite that transport activities do not represent the biggest contributor of pollutants emissions, their reduction has been a priority as some other externalities are associated to such emissions and to the transport itself. A crucial element to characterize the behavior of the vehicles against the environment are the losses that such vehicles exhibit in a passive way, that is, without any involvement of power conditions. The energy loses due to the rolling, the drag and to the friction in mechanical components, have been assessed so far in terms of the stopping acceleration when the vehicle idles on a ramp. However, such a testing procedure produces some uncertainties due to the dynamic conditions that are considered. To avoid such critical limitations, in this paper a testing procedure and facility are proposed, which are based on static conditions of the vehicle at the initiation and at the ending of the test, which are assumed to provide a better reliability to the testing. Some preliminary theoretical analysis should be made in order to validate the operational principles proposed herein for such testing facility.
KW - Road tankers
KW - Energy efficiency
KW - Environmental assessment
KW - Gravity response
KW - Transportation energy
KW - Rolling resistance
KW - Drag resistance
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511530
UR - https://www.iaras.org/iaras/home/caijes/a-method-to-assess-the-gravity-response-efficiency-of-a-truck
SN - 2367-8941
VL - 5
SP - 213
EP - 219
PB - IARAS
CY - Sofia
AN - OPUS4-51153
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hurtado-Hurtado, G.
A1 - Morales-Velazquez, L.
A1 - Valtierra-Rodríguez, M.
A1 - Otremba, Frank
A1 - Jáuregui-Correa, J. C.
T1 - Frequency Analysis of the Railway Track under Loads Caused by the Hunting Phenomenon
N2 - Hunting is a potentially dangerous phenomenon related to the lateral oscillation of the wheels that impacts the rails and causes the wear of the infrastructure’s components. Therefore, the analysis and timely detection of hunting can lead to the application of corrective maintenance tasks, reducing damages, and costs and even derailments as a result. In this work, the vibration response of a finite element model of a rail with hunting-induced loads by a single wheel is analyzed in three directions: longitudinal, lateral, and vertical. The contact patch forces are calculated by means of Simpack® using the Kalker linear theory and the contact Hertz theory. The system is solved by using the Newmark-_ approach. The results of the deflection and vibration analysis, following the proposed methodology, show how the different characteristics of the loads impact the rail.
KW - Continuous wavelet transform
KW - Empirical mode decomposition
KW - Finite element method
KW - Frequency analysis
KW - Hunting phenomenon
KW - Mechanical modelling
KW - Rail vibrations
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551517
UR - https://www.mdpi.com/2227-7390/10/13/2286/htm#
DO - https://doi.org/10.3390/math10132286
VL - 10
IS - 13
SP - 1
EP - 17
PB - MDPI
AN - OPUS4-55151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jauregui-Correa, J. C.
A1 - Morales-Velazquez, L.
A1 - Otremba, Frank
A1 - Hurtado-Hurtado, G.
T1 - Method for predicting dynamic loads for a health monitoring system for subway tracks
N2 - This paper presents a method for processing acceleration data registered on a train and determining the health condition of a subway’s substructure. The acceleration data was converted into a dynamic deformation by applying a transfer function defined using the Empirical Mode Decomposition Method.
The transfer function was constructed using data produced on an experimental rig, and it was scaled to an existing subway system. The equivalent deformation improved the analysis of the dynamic loads that affect the substructure of the subway tracks because it is considered the primary load that acts on the track and substructure. The acceleration data and the estimated deformations were analyzed with the Continues Wavelet Transform. The equivalent deformation data facilitated the application of a health monitoring system and simplified the development of predictive maintenance programs for the subway or railroad operators. This method better identified cracks in the substructure than using the acceleration data.
KW - Health monitoring
KW - Transfer function
KW - Railroad
KW - Substructure failures
KW - Dynamic loads
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557480
DO - https://doi.org/10.3389/fmech.2022.858424
SN - 2297-3079
VL - 8
SP - 1
EP - 16
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-55748
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hurtado-Hurtado, G.
A1 - Morales-Velazquez, L.
A1 - Otremba, Frank
A1 - Jáuregui-Correa, J. C.
T1 - Railcar Dynamic Response during Braking Maneuvers Based on Frequency Analysis
N2 - The dynamic response of a vehicle during braking is influenced by the tangential forces developed at the wheel-rail’s contact surface. The friction coefficient affects the load transfer from the wheel’s tread to the vehicle. In this work, the vibrations of a scale-down railway vehicle are monitored during braking and their relationship with the friction coefficient between wheel and rail is found out. The vehicle is instrumented with encoders, accelerometers, and is controlled via Bluetooth.
The tests are carried out with clean and friction-modified rails. The tangential forces transmitted from the wheel to the railcar’s body are visualized in time and frequency using a proposed correlation algorithm based on the outputs of the ContinuousWavelet Transform (CWT). The results demonstrate
that tangential forces have a significant impact on railway vehicles under conditions of high friction coefficients and large creep values.
KW - Railway vibration measurements
KW - Vibration signal analysis
KW - Wheel-rail tangential forces
KW - Railway braking forces
KW - Wheel-rail friction coefficient
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572309
DO - https://doi.org/10.3390/app13074132
VL - 13
IS - 7
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-57230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Treutler, K.
A1 - Wesling, V.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Modification of Co–Cr alloys to optimize additively welded microstructures and subsequent surface finishing
N2 - Cobalt chromium alloys are often used in turbine and plant construction. This is based on their high thermal and mechanical stress resistance as well as their high wear resistance to corrosive and abrasive loads. However, cobalt is a cost-intensive material that is difficult to machine. Moreover, increasingly complex structures and the optimisation of resource efficiency also require additive manufacturing steps for the production or repair of components in many sectors. Concerning inhomogeneity and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. As a result of the high stresses on the components
and requirements for a high surface quality, a complementary use of additive and machining manufacturing processes is necessary. Thereby, Co–Cr alloys are extremely challenging for machining with geometrically defined cutting edges because of their low thermal conductivity combined with high strength and toughness. An approach to solve this problem is to refine and homogenise the microstructure. This is achieved by modifying the alloy with elements zirconium and hafnium, which are added up to a maximum of 1 wt.-%. A reduction of the process forces and stresses on the tool and work piece surface is also achievable via hybrid milling processes. There are already studies on the combined use of additive and machining manufacturing processes based on laser technology. However, knowledge based on powder and wire-based arc processes is important, as these processes are more widespread. Furthermore, the effects on the surface zone of additively manufactured components by hybrid finish milling have not yet been a subject of research. The results show that the structural morphology could be significantly influenced with the addition of zirconium and hafnium.
KW - Alloy modification
KW - Ultrasonic-assisted milling
KW - Plasma-transferred arc welding
KW - Co-Cr-alloy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554182
DO - https://doi.org/10.1007/s40194-022-01334-0
SN - 0043-2288
SN - 1878-6669
SP - 1
EP - 13
PB - Springer
CY - Heidelberg
AN - OPUS4-55418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Hälsig, A.
A1 - Hensel, J.
A1 - Wandtke, Karsten
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Influence of Heat Control on Properties and Residual Stresses of Additive-Welded High-Strength Steel Components
N2 - This contributed to the knowledge regarding the safe avoidance of cold cracking. In addition to a thermophysical simulation using a dilatometer of different high-strength steels with subsequent tensile testing, reference WAAM specimens (open hollow cuboids) were welded while utilizing a high-strength filler metal (ultimate tensile strength > 790 MPa). The heat control was varied by means of the heat input and interlayer temperature such that the Dt8/5 cooling times corresponded to the recommended processing range (approx. 5 s to 20 s). For the heat input, significant effects were exhibited, in particular on the local residual stresses in the component. Welding with an excessive heat input or deposition rate may lead to low cooling rates, and hence to unfavorable microstructure and component properties, but at the same time, is intended to result in lower tensile residual stress levels. Such complex interactions must ultimately be clarified to provide users with easily applicable processing recommendations and standard specifications for an economical WAAM of high-strength steels. These investigations demonstrated a major influence of the heat input on both the cooling conditions and the residual stresses of components manufactured withWAAM using high-strength filler materials. A higher heat input led to longer cooling times (Dt8/5) and approx. 200 MPa lower residual stresses in the surface of the top layer.
KW - WAAM
KW - Additive manufacturing
KW - Heat control
KW - High-strength filler metals
KW - Residual stress
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553982
UR - https://www.mdpi.com/2075-4701/12/6/951
DO - https://doi.org/10.3390/met12060951
VL - 12
IS - 6
SP - 951
PB - MDPI
AN - OPUS4-55398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eissel, A.
A1 - Engelking, Lorenz
A1 - Treutler, K.
A1 - Schröpfer, Dirk
A1 - Wesling, V.
A1 - Kannengießer, Thomas
T1 - Investigations on influencing the microstructure of additively manufactured Co‑Cr alloys to improve subsequent machining conditions
N2 - Co-Cr alloys are frequently used for highly stressed components, especially in turbine and plant construction, due to their high resistance to thermal and mechanical stress, as well as to corrosive and abrasive loads. Furthermore, they are classified as difficult-to-cut materials because of their high strength and toughness as well as their low thermal conductivity. However, for Co, an increased cost and supply risk can be observed in recent years. Therefore, additive manufacturing (AM) offers significant economic advantages due to higher material efficiency regarding repair, modification, and manufacturing of such components. Concerning inhomogeneity and anisotropy of the microstructure and properties as well as manufacturing-related stresses, a lot of knowledge is still necessary for the economic use of additive welding processes in SMEs. In addition, subsequent machining, particularly contour milling, is essential to generate the required complex contours and surfaces. Hence, additive and machining manufacturing processes need to be coordinated in a complementary way, especially due to additional challenges arising in milling of heterogeneous hard-to-cut microstructures. Recently, it has been shown that modern, hybrid cutting processes, such as ultrasonic-assisted milling (US), can improve the cutting situation. In this investigation, the Co-Cr initial alloy is additionally modified with Ti and Zr up to 1 wt% with the aim to enhance the homogeneity of the microstructure and, thus, the machinability. Hence the investigation includes finish milling tests of the AM components and the comparison of US and conventional machining. Both the modifications and the ultrasonic assistance exhibit a significant effect on the machining situation; for example US causes a higher surface integrity of the finish milled surfaces compared to conventional milling.
T2 - International Congress on Welding, Additive Manufacturing and associated non-destructive testing
CY - Online meeting
DA - 08.06.2022
KW - Cobalt-chromium alloy
KW - Additive manufacturing
KW - Ultrasonic-assisted milling
KW - Surface integrity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560917
DO - https://doi.org/10.1007/s40194-022-01397-z
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-56091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Becker, Amadeus
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Determination of residual stress evolution during repair welding of high-strength steel components
N2 - During the assembly of steel structures, unacceptable weld defects may be found. An economical solution is local thermal gouging of the affected areas and re-welding. Due to high shrinkage restraints of repair weld and sur- rounding structure, high global and local welding stresses superimpose, and may lead to cracking and component failure, especially in connection with the degraded microstructure and mechanical properties of high-strength steels during the repair process. Component-related investigations of high-strength steels (FOSTA P1311/ IGF20162N) focus on welding residual stress evolution during local thermal gouging and rewelding. In this study, repair welding of S500MLO (EN 10225) is carried out using in-situ digital image correlation (DIC) and ex- situ X-ray diffraction (XRD) to analyse strains and stresses. Self-restrained slit specimen geometries were identified representing defined rigidity conditions of repair welds of real components, which were quantified using the restraint intensity concept. The specimens were rewelded with constant welding heat control and parameters. Weld specimens exhibited significantly increased transverse residual stresses with higher transverse restraint intensities, in the weld metal, and in the heat affected zone. Transverse stresses along the weld seam decrease at the weld seam ends leading to different stress state during gouging and welding. XRD analysis of the longitudinal and transverse local residual stresses after cooling to RT showed a good comparability with global DIC analyses.
KW - Repair-welding
KW - High-strength steels
KW - X-ray diffraction
KW - Digital image correlation
KW - Residual stresses
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555672
DO - https://doi.org/10.1016/j.finmec.2022.100073
SN - 2666-3597
VL - 6
SP - 1
EP - 6
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kaiser, Sebastian
A1 - Erxleben, Kjell
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Schweißen im Betrieb an Wasserstoff-Ferngasleitungen
N2 - Wasserstoff gilt als Energieträger für die Erreichung der Klimaziele und einer nachhaltigen zukünftigen Energieversorgung. Für den notwendigen Transport des Wasserstoffs in großem Maßstab und über weite Entfernungen ist eine zuverlässige Pipeline-Infrastruktur erforderlich. Umfassende weltweite Forschungsprojekte deuten auf die allgemeine Kompatibilität der verwendeten überwiegend ferritischen Stähle für die vorgesehenen Betriebsbedingungen von bis zu 60 °C bei 100 bar Wasserstoff hin. Dies ist jedoch nicht direkt übertragbar auf schweißtechnische Reparatur- und Wartungsarbeiten an im Betrieb befindlichen Pipelines. Ein im Erdgasnetz etabliertes Verfahren stellt das „Hot-Tapping“ dar, bei dem eine unter Druck stehende Pipeline im Betrieb angebohrt wird. Hierfür kommt ein an die Rohrleitung geschweißtes Formstück zum Einsatz, das die Montage der Bohr-/Lochschneidemaschine ermöglicht. In den Richtlinien EIGA 121/14 bzw. AIGA 033/14 wird darauf hingewiesen, dass das Anbohren von Wasserstoffleitungen kein Routineverfahren darstellt: “[…] a hydrogen hot-tap shall not be considered a routine procedure […]“. Dieser Aussage liegt unter anderem zugrunde, dass das Anschweißen des Formstücks an das Rohr und alle zu erwartenden Wärmebehandlungen vor und nach dem Schweißen eine lokale Temperaturerhöhung verursachen. Insbesondere auch an der Rohrinnenfläche, die dem Wasserstoff ausgesetzt ist. Diese erhöhten Temperaturen begünstigen die Absorption und Diffusion von Wasserstoff in das Material. Besonders zu beachten ist außerdem die lokal auftretende kurzzeitige Austenitisierung des Materials, die eine lokal stark erhöhte Wasserstoffkonzentration verursachen kann. Aus den genannten Gründen gibt diese Studie einen kurzen Überblick über die derzeit weltweit verfügbaren Forschungsprojekte zum Schweißen von Wasserstoff-Pipelines im Betrieb. Vorgestellt werden unter anderem erste Ergebnisse des Kooperationsforschungsprojektes H2SuD, das derzeit an der BAM bearbeitet wird.
T2 - 6. Symposium Materialtechnik
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - Materialdegradation
KW - Pipeline
KW - Schweißen
KW - Wasserstoff
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632731
SN - 978-3-8440-9961-4
SN - 978-3-8191-0041-3
DO - https://doi.org/10.21268/20250506-12
SN - 2364-0804
SN - 3052-3524
N1 - Serientitel: Fortschrittsberichte der Materialforschung und Werkstofftechnik – Series title: Bulletin of Materials Research and Engineering
VL - 15
SP - 381
EP - 390
PB - Shaker Verlag
CY - Düren
AN - OPUS4-63273
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Eissel, A.
A1 - Treutler, K.
A1 - Wesling, V.
T1 - Alloy modification for additive manufactured Ni alloy components Part II: Effect on subsequent machining properties
N2 - Alloy 36 (1.3912) is an alloy with 36% nickel and 64% iron and is generally classified as a difficult-to-cut material. Increasingly complex structures and the optimization of resource efficiency are making additive manufacturing (AM) more and more attractive for the manufacture or repair of components. Subsequent machining of AM components is unavoidable for its final contour. By using modern, hybrid machining processes, e.g., ultrasonic-assisted milling (US), it is possible to improve the cutting situation regarding the resulting surface integrity as well as the cutting force. Part I deals with the influence of the alloying elements Ti, Zr, and Hf on the microstructure and the hardness of the initial alloy 36. Part II focusses on the effect of the alloy modifications and the ultrasonic assistance on machinability as well as on the surface integrity after finish-milling. The results show a highly significant influence of the ultrasonic assistance. The cutting force during the US is reduced by over 50% and the roughness of approx. 50% compared to conventional milling (CM) for all materials investigated. Moreover, the US causes a defect-free surface and induces near-surface compressive residual stresses. CM leads to a near-surface stress state of approx. 0 MPa.
T2 - 75th IIW Annual Assembly
CY - Tokyo, Japan
DA - 17.07.2022
KW - Alloy 36
KW - Ultrasonic-assisted milling
KW - Surface integrity
KW - Modification of structural morphology
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566609
DO - https://doi.org/10.1007/s40194-022-01438-7
SP - 1
EP - 8
PB - Springer
CY - Heidelberg
AN - OPUS4-56660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Nina
A1 - Kromm, Arne
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Innovatives Instandsetzungsschweißen von Altstahl: Materialverhalten und Herausforderungen
N2 - Aus Gründen der Nachhaltigkeit und Wirtschaftlichkeit gibt es in der stahlverarbeiten-den Industrie einen Trend zum Bauen im Bestand, um kostenintensive Sperrungen oder Rückbau zu vermeiden. Schweißen wird dabei als wirtschaftliches Fügeverfahren im Zusammenhang mit Altstählen kaum genutzt, obwohl Nieten- und Schraubenverbindungen oft unwirtschaftlich sind. Für die Instandsetzung ist häufig beschädigtes Bestands-material durch neue Stähle zu ersetzen bzw. Alt-Neu-Stahl-Mischverbindungen herzu-stellen. Aufgrund der verschiedenen Herstellungsprozesse von Altstählen ist nicht jeder Stahl aus dem 20. Jahrhundert schweißgeeignet. Daher ist zunächst eine Schweißeignungsprüfung erforderlich. In den vorliegenden Untersuchungen wurden verschiedene Altstähle hinsichtlich ihres Schweißverhaltens mittels Dilatometrie analysiert. Ziel war es, eine Datenbasis aus Schweiß-Zustands-Zeit-Diagrammen und Simulationen der Wärmeeinflusszone zu erstellen, um praxisrelevante Schweißuntersuchungen ableiten zu können. Diese geben wesentlichen Aufschluss hinsichtlich ihres schweißmetallurgischen Verhaltens und ihrer Schweißeignung. Solche Grundlagen sind zur Entwicklung innovativer schweißtechnischer Konzepte zur beanspruchungsgerechten Instandsetzung bestehender Altstahl-Infrastruktur in Deutschland notwendig.
T2 - 6. Symposium Materialtechnik, 20. bis 21. Februar 2025
CY - Clausthal-Zellerfeld, Germany
DA - 20.02.2025
KW - Altstahl
KW - Schweiß-ZTU Diagramme
KW - Instandsetzungsschweißen
KW - Schweißeignungsprüfung
KW - Dilatometrie
PY - 2025
SN - 978-3-8440-9961-4
DO - https://doi.org/10.21268/20250505-1
VL - 15
SP - 370
EP - 380
PB - Shaker Verlag GmbH
CY - Düren
AN - OPUS4-63377
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
A1 - Flohr, Kerstin
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
ED - Holden, T.M.
ED - Muránsky, O.
ED - Edwards, L.
T1 - Multi-axial Analyses of Welding Stresses in High-Strength Steel Welds
N2 - Today’s efforts for lightweight design result in a growing application of high-strength structural steels from 960 MPa. In welded structures of these steels increased demands regarding component safety and a high elastic ratio should be considered. Hence, the prevention of an evolution of high weld-induced tensile residual stresses is required. Recent studies showed that component related restraint conditions of welds are able to elevate welding induced stresses to critical values, depending on material characteristics, the welding process and parameters. This work involves multi-axial welding loads as a consequence of the superposition of local residual stresses, global reaction stresses and moments, varying the welding parameters under different restraint conditions. The global welding loads are measured via GMA-weld tests in a special testing facility and via a DIC(Digital Image Correlation)-system in a slot weld. Local transverse residual stresses were analysed by means of X-ray diffraction. The application of a less amount of weld runs due to a modified welding parameters and welds seam configurations revealed as a beneficial approach to reduce welding loads in high-strength steels.
T2 - 10th International Conference on Residual Stresses
CY - Sydney, Australia
DA - 04.07.2016
KW - High-Strength Steel
KW - Welding
KW - Reaction Stress
KW - X-Ray Diffraction
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390453
SN - 978-1-9452-9116-6
DO - https://doi.org/10.21741/9781945291173-35
SN - 2474-395X
VL - 2
SP - 205
EP - 210
PB - Materials Research Forum LLC.
CY - Millersville PA, USA
AN - OPUS4-39045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dixneit, Jonny
A1 - Kromm, Arne
A1 - Boin, M.
A1 - Kannengießer, Thomas
A1 - Gibmeier, J.
ED - Olden, T.-M.
ED - Muransky, O. Muransky
ED - Edwards, L.
T1 - Influence of heat control on residual stresses in low transformation temperature (LTT) large scale welds
N2 - The current paper presents residual stress analyses of large scale LTT (Low Transformation Temperature) welds. LTT filler materials are specially designed for residual stress engineering by means of an adjusted martensite phase transformation. Controlling the level of mostly detrimental residual stresses already during the welding process would be highly attractive as time and cost consuming post processing may be prevented. In large scale welds the residual stress state is influenced by the heat control (e.g. interpass temperature) during welding. Therefore, welding residual stresses are studied here putting the focus on the influence of welding process parameters while joining heavy steel sections with a thickness of 25 mm. The residual stress state was determined at the top surface using X-ray diffraction as well as in the bulk by neutron diffraction. The results show that control of the interpass temperature is vital for the residual stresses present in the joints. This accounts for the top surface but is most pronounced for the bulk of the welds. While high interpass temperatures are appropriate to induce compressive residual stresses in the weld metal, low interpass temperatures favor unwanted tensile residual stresses instead.
T2 - ICRS 2016 - 10th International Conference on Residual Stresses
CY - Sydney, Australia
DA - 03.07.2016
KW - LTT
KW - Welding residual stress
KW - Phase transformation
KW - Interpass temperature
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389628
SN - 978-1-94529117-3
SN - 978-1-94529116-6
DO - https://doi.org/10.21741/9781945291173-38
SN - 2474-395X
VL - 2
SP - 223
EP - 228
PB - Materials Research Forum LLC
CY - Millersville (PA), USA
AN - OPUS4-38962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
A1 - Schasse, R.
A1 - Xu, Ping
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
ED - Olden, T.-M.
ED - Muransky, O.
ED - Edwards, L.
T1 - Influence of weld repair by gouging on the residual stresses in high strength steels
N2 - Carbon arc-air gouging is a common technology when repairing defects in welded structures. Often this technique is applied in repeated cycles even on the same location of the joint. Due to the multiple heat input by gouging and subsequent re-welding, the residual stresses are strongly influenced. This can become crucial when microstructure and mechanical properties are adversely affected by multiple weld reparations. Knowledge about the relation of gouging and residual stresses is scarce but important when high strength steels, which are sensitive to residual stresses, are processed. The present study shows the effect of repair welding on a high strength steel structural element. The weld and the heat affected zone were subjected to multiple thermal cycles by gouging and subsequent repair welding. The residual stresses were determined by X-ray diffraction at different positions along the joint. The results showed that the residual stress level has increased by the repair cycles. This is most pronounced for the heat affected zone. Adapted welding procedures may prevent detrimental residual stress distributions.
T2 - ICRS 2016 - 10th International Conference on Residual Stresses
CY - Sydney, Australia
DA - 03.07.2016
KW - Repair welding
KW - Weld residual stress
KW - Carbon arc-air gouging
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389242
SN - 978-1-94529117-6
SN - 978-1-94529117-3
DO - https://doi.org/10.21741/9781945291173-29
SN - 2474-395X
VL - 2
SP - 169
EP - 174
PB - Materials Research Forum LLC
CY - Millersville, PA, USA
AN - OPUS4-38924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lausch, Thomas
A1 - Kannengießer, Thomas
A1 - Bohse, Jürgen
A1 - Schmitz-Niederau, M.
T1 - Schallemissionsmessung an Bauteilschweißungen aus 13CrMoV9-10 zum Nachweis von Spannungsrelaxationsrissen
N2 - In einer speziellen 3D-Prüfanlage zur wirklichkeitsnahen Simulation von komplexen Verhältnissen an Großproben wurden UP-Mehrlagenschweißungen am warmfesten Stahl 13CrMoV9-10 durchgeführt. Während der schweißtechnischen Fertigung und der Abkühlung auf Raumtemperatur wurden die Proben an der freien Ausdehnung und Schrumpfung gehindert. Die daraus resultierenden Reaktionsspannungen führten während der Wärmenachbehandlung zu Relaxationsrissen in der Wärmeeinflusszone. Das Spannungsarmglühen wurde bei einer Temperatur von 705°C und einer Haltezeit von 8 h durchgeführt. Während der Aufheiz- und Abkühlphasen wurde die thermische Ausdehnung der Probe über die 3D-Prüfanlage kompensiert und damit das Spannungsniveau bis zum Erreichen der maximalen Glühtemperatur aufrechterhalten. Nach Erreichen der Glühtemperatur konnte die Probe relaxieren. Der Einsatz der Schallemissionsmessung ermöglichte es die Entstehung von Spannungsrelaxationsrisse, erstmalig online, nachzuweisen. Durch Synchronisierung der Schallemissionsereignisse mit den Messdaten der 3D – Prüfanlage wurde der kritische Temperaturbereich für das Auftreten von Spannungsrelaxationsrissen bestimmt. Die Rissinitiierung findet im Temperaturbereich zwischen 350°C - 500°C statt. Aussagen über das Risswachstum können auf Grund der ungünstigen Versuchsbedingungen, mit Emission von Störgeräuchen, nicht getroffen werden.
T2 - 19. Kolloquium Schallemission - Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse
CY - Augsburg, Germany
DA - 12.09.2013
KW - Spannungsrelaxationsrisse
KW - SRC
KW - Schallemission
KW - 13CrMoV9-10
KW - Schrumpfbehinderung
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-291616
SN - 978-3-940283-51-1
N1 - Serientitel: DGZfP-Berichtsband – Series title: DGZfP-Berichtsband
IS - 142
SP - 1
EP - 19 (Beitrag 14)
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung
CY - Berlin
AN - OPUS4-29161
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröpfer, Dirk
A1 - Kromm, Arne
A1 - Hannemann, Andreas
A1 - Kannengießer, Thomas
ED - Seefeldt, Marc
T1 - In-situ determination of critical welding stresses during assembly of thick-walled components made of high-strength steel
N2 - The performance and safety of welded high-strength low-alloyed steel (HSLA) components are substantially affected by the stresses occurring during and after welding fabrication, especially if welding shrinkage and distortion are severely restrained. The surrounding structure of the whole component affects loads in the far-field superimposing with welding stresses in the near-field of the weld. In this study a unique testing facility was used to restrain shrinkage and bending while analyse multiaxial far-field loads (max. 2 MN) during assembly of thick-walled component. A novel approach for the assessment of the in-situ-measured far-field data in combination with the actual weld geometry was elaborated. For the first time, analyses of the global bending moments of restrained welds based on the neutral axis of the actual weld load bearing section were achieved. Hence, far-field measurements offered the possibility to determine critical near-field stresses of the weld crosssections for the entire joining process. This work presents the approach for far-to-near field in-situ determination of stresses in detail for the 2-MN-testing system based on an extensive experimental work on HSLA steel welds, which demonstrates sources and consequences of these high local welding stresses. Thus, it was clarified, why the first weld beads are crucial regarding welding stresses and cold cracking, which is well known, but has never been measured so far. Accompanying analyses using X-ray diffraction (XRD) after welding show effects on local residual stress distributions. These analyses indicated viable prospects for stress reduction during assembly of thick-walled HSLA steel components.
T2 - European Conference on Residual Stresses 2018 - ECRS-10
CY - Leuven, Belgium
DA - 11.09.2018
KW - Residual stress
KW - Welding
KW - Large-scale test
KW - X-ray diffraction
KW - HSLA steel
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-466053
SN - 978-1-9452-9188-3
SN - 978-1-9452-9189-0
DO - https://doi.org/10.21741/9781945291890-30
SN - 2474-395X
SN - 2474-3941
VL - 6
SP - 191
EP - 196
PB - Materials Research Forum LLC
CY - Millersville, PA, USA
AN - OPUS4-46605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krankenhagen, Rainer
A1 - Altenburg, Simon
A1 - Eisenkrein, Helena
T1 - Photothermische Schichtdickenmessung an Betonbeschichtungen - unter Laborbedingungen und auf der Baustelle
N2 - Bei der Realisierung von Oberflächen-Schutz-System (OSS) auf Betonflächen ist die tatsächlich erreichte Dicke der Beschichtung ein wesentlicher Parameter, der über die Funktionalität und Langzeitstabilität der aufgetragenen Schicht entscheidet. Die Firma IBOS und die BAM haben in den letzten Jahren gemeinsam einen funktionstüchtigen Prototyp eines Messgeräts zur zerstörungsfreien Schichtdickenmessung für Bodenbeschichtungen entwickelt. Hierin wird die Abkühlkurve eines vorher erwärmten Bereichs berührungslos mit einer IR-Kamera erfasst und mit einem Modell verglichen, was die Bestimmung der Schichtdicke ermöglicht. Im Rahmen dieses Beitrags wird die Umsetzung der Methode unter Laborbedingungen und in der Praxis auf der Baustelle erläutert und diskutiert.
T2 - DGZfP-Jahrestagung
CY - Leipzig, Germany
DA - 07.05.2018
KW - Betonbeschichtung
KW - Oberflächenschutzsystem
KW - Schichtdickenmessung
KW - Zerstörungsfreie Prüfung
KW - Photothermisch
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449433
UR - https://www.ndt.net/?id=23060
SN - 1435-4934
VL - 23
IS - 9
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-44943
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Kromm, Arne
A1 - Schröpfer, Dirk
A1 - Steger, J.
A1 - Kannengießer, Thomas
ED - Seefeldt, M.
T1 - Residual stress formation in component related stress relief cracking tests of a welded creep-resistant steel
N2 - Submerged arc welded (SAW) components of creep-resistant low-alloyed Cr-Mo-V steels are used for thick-walled heavy petrochemical reactors (wall-thickness up to 475 mm) as well as employed in construction of modern high-efficient fossil fired power plants. These large components are accompanied by significant restraints during welding fabrication, especially at positions of different thicknesses like welding of nozzles. As a result, residual stresses occur, playing a domi-nant role concerning so-called stress relief cracking (SRC) typically during post weld heat treat-ment (PWHT). Besides specific metallurgical factors (like secondary hardening due to re-precipitation), high tensile residual stresses are a considerable influence factor on SRC. For the assessment of SRC susceptibility of certain materials mostly mechanical tests are applied which are isolated from the welding process. Conclusions regarding the influence of mechanical factors are rare so far. The present research follows an approach to reproduce loads, which occur during welding of real thick-walled components scaled to laboratory conditions by using tests designed on different measures. A large-scale slit specimen giving a high restraint in 3 dimensions by high stiffness was compared to a medium-scale multi-pass welding U-profile specimen showing a high degree of restraint in longitudinal direction and a small-scale TIG-re-melted specimen. The small-scale specimens were additionally subjected to mechanical bending to induce loads that are found during fabrication on the real-scale in heavy components. Results show for all three cases compa-rable high tensile residual stresses up to yield strength with high gradients in the weld metal and the heat affected zone. Those high tensile stresses can be significant for cracking during further PWHT.
T2 - European Conference on Residual Stresses 2018 - ECRS-10
CY - Leuven, Belgium
DA - 11.09.2018
KW - Welding
KW - Residual stresses
KW - Stress Relief Cracking (SRC)
KW - Creep-resistant steel
KW - Post Weld Heat Treatment (PWHT)
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459683
SN - 978-1-9452-9188-3
SN - 978-1-9452-9189-0
DO - https://doi.org/10.21741/9781945291890-29
SN - 2474-395X
SN - 2474-3941
VL - 6
SP - 185
EP - 190
PB - Materials Research Forum LLC
CY - Millersville, PA, USA
AN - OPUS4-45968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rhode, Michael
A1 - Mente, Tobias
A1 - Kannengießer, Thomas
A1 - Czeskleba, Denis
T1 - Simulation of hydrogen distribution in submerged arc welded heavy plates as tool for evaluating cold cracking sensitivity for offshore structures
N2 - Foundation structures for offshore wind turbines are typically made of heavy plate struc-tural steels, such as S420ML, welded by submerged arc welding. Due to the welding process conditions, higher amounts of hydrogen can be introduced. In this context, large plate thicknesses result in long diffusion paths and a prolonged diffusion time for hydrogen at ambient temperature and possible delayed hydrogen-assisted cold cracking. As a result, hydrogen can accumulate in areas of high mechanical stress and strain. Due to the delayed diffusion, a minimum waiting time of up to 48 h must be observed before non-destructive testing can be performed. In addition, the assessment of possible cold crack locations is very complex. For this reason, a numerical model of a component-like weld test was developed to simulate the temperature field during welding and subsequent cooling. A hydrogen diffusion model based on the temporal-local temperature distribution was established. It was applied to simulate the change of hydrogen distribution as a function of temperature cycle during multi-layer welding and further for the entire waiting time interval ≤ 48 h. As a result, crack critical areas could be evaluated in terms of accu-mulated hydrogen. An advantage of the diffusion model is the simulation of a normalized concentration, i.e. between "0" (no hydrogen) and "1" (max. concentration), which can be scaled to experimentally determined hydrogen concentrations. Finally, selected results for increased real hydrogen ingress are presented, which confirm the relatively high crack resistance of the S420 submerged arc welded joint.
KW - Hydrogen assisted cracking
KW - Diffusion
KW - Numerical simulation
KW - Offshore steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632416
DO - https://doi.org/10.21268/20250507-6
SP - 1
EP - 12
PB - Technische Universität Clausthal
CY - Clausthal-Zellerfeld, Deutschland
AN - OPUS4-63241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Ernst, W.
A1 - Spindler, H.
A1 - Kannengießer, Thomas
T1 - Hydrogen-assisted cracking of GMA welded 960 MPa grade high-strength steels
N2 - High-strength steels with yield strength of 960 MPa are susceptible to hydrogen-assisted cracking (HAC) during welding processing. In the present paper, the implant test is used to study HAC in a quenched and tempered steel S960QL and a high-strength steel produced by thermo-mechanical controlled process S960MC. Welding is performed using the gas metal arc welding process. Furthermore, diffusible hydrogen concentration (HD) in arc weld metal is determined. Based on the implant test results, lower critical stress (LCS) for complete fracture, critical implant stress for crack initiation, and embrittlement index (EI) are determined. At HD of 1.66 ml/100 g, LCS is 605 MPa and 817 MPa for S960QL and S960MC, respectively. EI is 0.30 and 0.46 for S960QL and S960MC, respectively. Fracture surfaces of S960QL show higher degradation with reduced deformation. Both, higher EI of S960MC and fractography show better resistance to HAC in the HAZ of S960MC compared to S960QL.
KW - High-strength steel
KW - Welding
KW - Diffusible hydrogen
KW - Hydrogen-assisted cracking
KW - Heat-affected zone
KW - Implant test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510307
DO - https://doi.org/10.1016/j.ijhydene.2020.05.077
SN - 0360-3199
VL - 45
IS - 38
SP - 20080
EP - 20093
PB - Elsevier Ltd
CY - Amsterdam, NL
AN - OPUS4-51030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thomas, Maximilian
A1 - Vollert, F.
A1 - Weidemann, Jens
A1 - Gibmeier, J.
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Surface- and volume-based investigation on influences of different Varestraint testing parameters and chemical compositions on solidification cracking in LTT filler metals
N2 - The subject of this study is how, and to what extent, Varestraint/Transvarestraint test results are influenced by both testing parameters and characteristics of evaluation methods. Several different high-alloyed martensitic LTT (low Transformation temperature) filler materials, CrNi and CrMn type, were selected for examination due to their rather distinctive solidification cracking behaviour, which aroused interest after previous studies. First, the effects of different process parameter sets on the solidification cracking response were measured using standard approaches. Subsequently, microfocus X-ray computer tomography (μCT) scans were performed on the specimens. The results consistently show sub-surface cracking to significant yet varying extents. Different primary solidification types were found using wavelength dispersive X-ray (WDX) analysis conducted on filler metals with varying Cr/Ni equivalent ratios. This aspect is regarded as the main difference between the CrNiand CrMn-type materials in matters of cracking characteristics. Results show that when it comes to testing of modern highperformance alloys, one set of standard Varestraint testing parameters might not be equally suitable for all materials. Also, to properly accommodate different solidification types, sub-surface cracking has to be taken into account.
KW - Solidification cracking
KW - Varestraint testing
KW - MVT
KW - LTT filler metal
KW - Microfocus X-ray computer tomography (μCT)
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506039
DO - https://doi.org/10.1007/s40194-020-00895-2
VL - 64
SP - 913
EP - 923
PB - Springer Nature
CY - Heidelberg, New York
AN - OPUS4-50603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part II - Mechanisms of stress relief cracking during post weld heat treatment
N2 - Welding of 13CrMoV9-10 vanadium steel requires care due to an increased susceptibility to stress relief cracking during post weld heat treatment. Previous research into the crack formation in creep-resistant steels has focused on thermal and metallurgical factors; however, little knowledge has been gathered regarding the crack formation during post weld heat treatment considering real-life restraint conditions. This work is subdivided in two parts. Part I showed that an increasing heat input during submerged arc welding under restraint led to an increasing stress level in the joint prior to the post weld heat treatment. The magnitude of stress relief cracking observed in the heat-affected zone after the post weld heat treatment is affected by the heat input. In Part II of this work, the cracks and the associated microstructure which occurred under restraint were studied. The application of a Special acoustic emission analysis indicated that the cracks formed in a temperature range between 300 and 500 °C during the post weld heat treatment. The toughness in the heat-affected zone of the restrained welds was affected by the welding heat input.
Microstructural analyses of all specimens revealed accelerated aging due to precipitation of carbides during post weld heat treatment under restraint.
KW - Welding
KW - Creep-resistant steel
KW - Post weld heat treatment
KW - Stress relief cracking
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506283
DO - https://doi.org/10.1007/s40194-020-00881-8
SN - 1878-6669
VL - 64
SP - 819
EP - 829
PB - Springer
CY - Berlin
AN - OPUS4-50628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Lausch, Thomas
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
T1 - Influence of welding stresses on relief cracking during heat treatment of a creep-resistant 13CrMoV steel: Part I - Effect of heat control on welding stresses and stress relief cracking
N2 - The avoidance of failures during the fabrication or operation of petrochemical reactors made of creep-resistant, low-alloy steels as 13CrMoV9-10 requires still research despite over 60 years of international investigations in the field of stress relief cracking. The quality of modern base materials and filler metals leads to the fact that previously known crack causes, such as impurities of S or P, recede into the background. Rather, the causes are increasingly to be found in the fabrication process. Investigations on the influence of heat control on the stresses in welded components and thus on the stress relief cracking sensitivity under realistic manufacturing conditions are not yet available. This work is subdivided in two parts. Part 1 of this study focused on the effect of heat control during submerged arc welding on the stresses. For this purpose, a testing facility was applied, which allows to observe the forces and moments accumulating during welding or heat treatment in a component-like specimen under shrinkage restraint. The stress acting in the specimen increases with higher preheat/interpass temperatures and higher heat input. During the heat treatment, the stresses are relieved. Nevertheless, cracks are formed already during heating. The total crack length correlates with the heat input.
KW - Welding
KW - Creep-resistant steel
KW - Post weld heat treatment
KW - Stress relief cracking
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506271
DO - https://doi.org/10.1007/s40194-020-00875-6
SN - 1878-6669
VL - 64
IS - 5
SP - 807
EP - 817
PB - Springer
CY - Berlin
AN - OPUS4-50627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Plouffe, A.
A1 - Lee, R. G.
A1 - Byrne, K.
A1 - Kjarsgaard, I. M.
A1 - Petts, D. C.
A1 - Wilton, D.H.C.
A1 - Ferbey, T.
A1 - Oelze, Marcus
T1 - Tracing Detrital Epidote Derived from Alteration Halos to Porphyry Cu Deposits in Glaciated Terrains: The Search for Covered Mineralization
N2 - Distal alteration related to porphyry Cu mineralization is typically characterized by an abundance of green minerals, such as epidote, tremolite, and chlorite, within the propylitic and sodic-calcic alteration zones and extends far outside (>1 km) the mineralized zone(s). Glacial erosion and dispersal derived from rocks affected by propylitic and sodic-calcic alteration have resulted in the development of extensive dispersal trains of epidote in till (glacial sediment) that can reach 8 to 330 km2 as observed at four porphyry Cu study sites in the Quesnel terrane of south-central British Columbia: Highland Valley Copper, Gibraltar, Mount Polley, and Woodjam deposits. At each of these sites, epidote is more abundant in heavy mineral concentrates of till collected directly over and down-ice from mineralization and associated alteration. Epidote grains in till with >0.6 ppm Sb and >8 ppm As (as determined by laser ablation-inductively coupled plasma-mass spectrometry) are attributed to a porphyry alteration provenance. There is a greater abundance of epidote grains with high concentrations of trace elements (>12 ppm Cu, >2,700 ppm Mn, >7 ppm Zn, and >37 ppm Pb) in each porphyry district com� pared to background regions. This trace element signature recorded in till epidote grains is heterogeneously distributed in these districts and is interpreted to reflect varying degrees of metal enrichment from a porphyry fluid source. Tracing the source of the epidote in the till (i.e., geochemically tying it to porphyry-related propy� litic and/or sodic-calcic alteration), coupled with porphyry vectoring tools in bedrock, will aid in the detection of concealed porphyry Cu mineralization in glaciated terrains.
KW - Indicator minerals
KW - Porphyry Cu deposits
KW - Epidote
KW - Glaciated terrains
KW - Propylitic alteration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635209
DO - https://doi.org/10.5382/econgeo.5049
SN - 1554-0774
VL - 119
IS - 2
SP - 305
EP - 329
PB - Society of Economic Geologists, Inc.
AN - OPUS4-63520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brosig, Laura
A1 - Horn, Wolfgang
A1 - Pyza, Lars
A1 - Jann, Oliver
A1 - Plehn, W.
T1 - Round robin test for the implementation of odour measurements according to DIN ISO 16000-28 into the assessment of emissions from building products
N2 - Odour measurements become increasingly important in view of the assessment of indoor air quality and the emissions of building products. Hence they need to be implemented into evaluation schemes such as the AgBB scheme. While there are already standards like DIN ISO 16000-28 and VDI 4302 Part 1 specifying the procedure of odour measurements using a comparison scale, no final validation of the method has been carried out so far. Therefore, a round robin test was conducted in 2012 with 12 participating laboratories that mainly consisted of the following two parts: 1) testing of the available comparison scales with respect to their operational performance and 2) execution of an odour assessment of an acrylic sealant using emission test chambers. Part one included the measurement of the air flow rates and the provided concentrations of the reference substance (acetone). Part two was conducted to test the performance of the laboratories and the applicability of DIN ISO 16000-28 and supplementary VDI 4302 Part 1 by assessing the perceived intensity and the hedonic tone of the air samples. Moreover, samples for VOC analysis were taken from the air in the emission test chamber on the 7th day of testing to allow for quality control. Resulting from this round robin test main deficits were detected and suggestions for the improvement of the odour measurement procedure were made.
N2 - Im Rahmen der Bewertung von Innenraumluftqualität und von Emissionen aus Bauprodukten gewinnt auch die Beurteilung entstehender Gerüche zunehmend an Bedeutung. Um der daraus resultierenden Forderung nach Geruchsbewertungen gerecht zu werden, müssen entsprechende Methoden in bestehende Bewertungssysteme, wie z. B. das AgBB-Schema, aufgenommen werden. Als Grundlage hierfür bieten sich die bereits bestehenden Regelwerke DIN ISO 16000-28 und VDI 4302 Blatt 1 an, die das Vorgehen bei Geruchsmessungen unter Verwendung eines Vergleichsmaßstabes vorgeben. Da für die beschriebene Methode bisher keine Validierung vorliegt, wurde 2012 ein Ringversuch mit zwölf Instituten durchgeführt, der sich hauptsächlich aus zwei Teilen zusammensetzte: 1) Überprüfung der technischen Funktionsfähigkeit der verwendeten Vergleichsmaßstäbe und 2) Durchführung einer Geruchsbewertung für eine Acryldichtmasse mithilfe von Emissionsprüfkammern. Im ersten Teil wurden sowohl die Volumenströme als auch die bereitgestellten Konzentrationen der Referenzsubstanz Aceton bestimmt. Der zweite Teil diente neben der Ermittlung der Leistungsfähigkeit der Laboratorien vor allem der Feststellung, inwieweit eine Bestimmung der empfundenen Intensität und der Hedonik nach DIN ISO 16000-28, ergänzt durch VDI 4302 Blatt 1, einheitlich möglich ist. Aus Gründen der Vergleichbarkeit und der Qualitätskontrolle wurden am siebten Tag der Messungen zusätzlich Proben der Prüfkammerluft zur VOC-Bestimmung genommen. Mithilfe des Ringversuchs konnten Defizite sowohl technischer als auch methodischer Art festgestellt und Vorschläge für die Verbesserung des Vorgehens bei Geruchsbewertungen erarbeitet werden.
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-293110
UR - http://www.gefahrstoffe.de/gest/article.php?data[article_id]=75118
SN - 0949-8036
SN - 0039-0771
SN - 1436-4891
VL - 73
IS - 10
SP - 441
EP - 445
PB - Springer-VDI-Verlag
CY - Düsseldorf
AN - OPUS4-29311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Matthias
A1 - Horn, Wolfgang
A1 - Juritsch, Elevtheria
A1 - Klinge, A.
A1 - Radeljic, L.
A1 - Jann, Oliver
T1 - Natural building materials for interior fitting and refurbishment - What about indoor emissions?
N2 - Indoor air quality can be adversely affected by emissions from building materials, consequently having a negative impact on human health and well-being. In this study, more than 30 natural building materials (earth dry boards and plasters, bio-based insulation materials, and boards made of wood, flax, reed, straw, etc.) used for interior works were investigated as to their emissions of (semi-) volatile organic compounds ((S)VOC), formaldehyde, and radon. The study focused on the emissions from complete wall build-ups as they can be used for internal Partition walls and the internal insulation of external walls. Test chambers were designed, allowing the compounds to release only from the surface of the material facing indoors under testing Parameters that were chosen to simulate model room conditions. The emission test results were evaluated using the AgBB evaluation scheme, a procedure for the health-related evaluation of construction products and currently applied for the approval of specific groups of building materials in Germany.
Seventeen out of 19 sample build-ups tested in this study would have passed this scheme since they generally proved to be low-emitting and although the combined emissions of multiple materials were tested, 50% of the measurements could be terminated before half of the total testing time.
KW - Bio-based insulation
KW - Earthen building materials
KW - Volatile organic compounds
KW - Semivolatile organic compounds
KW - Radon
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519634
DO - https://doi.org/10.3390/ma14010234
VL - 14
IS - 1 (Special issue: Measurement of the environmental impact of materials)
SP - 234-1
EP - 234-14
PB - MDPI
CY - Basel
AN - OPUS4-51963
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilke, Olaf
A1 - Horn, Wolfgang
A1 - Richter, Matthias
A1 - Jann, Oliver
T1 - Volatile organic compounds from building products - Results from six round robin tests with emission test chambers conducted between 2008 and 2018
N2 - Emission testing of volatile organic compounds (VOC) from materials and products is commonly based on emission test chamber measurements. To ensure the comparability of results from different testing laboratories, their measurement performance must be verified. For this purpose, Bundesanstalt für Materialforschung und -prüfung (BAM) organizes an international proficiency test (round robin test, RRT) every two years using well-characterized test materials (one sealant, one furniture board, and four times a lacquer) with defined VOC emissions. The materials fulfilled the requirements of homogeneity, reproducibility, and stability. Altogether, 36 VOCs were included of which 33 gave test chamber air concentrations between 13 and 83 µg/m3. This is the typical concentration range to be expected and to be quantified when performing chamber tests. Three compounds had higher concentrations between 326 and 1105 µg/m3. In this paper, the relative standard deviations (RSD) of BAM round robin tests since 2008 are compared and the improvement of the comparability of the emission chamber testing is shown by the decrease of the mean RSD down to 28 % in 2018. In contrast, the first large European interlaboratory comparison in 1999 showed a mean RSD of 51 %.
KW - Construction product
KW - Emission test chamber
KW - Interlaboratory comparison
KW - Proficiency testing
KW - Rround robin test
KW - VOC emission
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526139
DO - https://doi.org/10.1111/ina.12848
VL - 31
IS - 6
SP - 2049
EP - 2057
PB - Wiley
AN - OPUS4-52613
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brandt, S.
A1 - Müller, B.
A1 - Brozowski, F.
A1 - Plehn, W.
A1 - Horn, Wolfgang
T1 - Weiterentwicklung des Geruchsmessverfahrens für Bauprodukte
T1 - Further development of the odour measurement method for building products
N2 - Bauprodukte und Einrichtungsgegenstände für Innenräume, wie Bodenbeläge und Wandpaneele, sollen das Wohlbefinden und die Gesundheit der Raumnutzerinnen und -nutzer nicht durch das Ausdünsten von Geruchsstoffen stören. Mit der Geruchsprüfung nach ISO 16000-28 „Innenraumluft - Bestimmung der Geruchsstoffemissionen aus Bauprodukten mit einer Emissionsprüfkammer“ wird der Produktgeruch zu einer messbaren Größe. So kann z. B. die empfundene Intensität, also die Stärke eines Geruchseindruckes, mit Hilfe eines Vergleichsmaßstabes von Probandinnen und Probanden ermittelt werden. Im hier vorgestellten Projekt werden Vorschläge zur Weiterentwicklung der Methode vorgestellt, um im Ergebnis die Reproduzierbarkeit der Messergebnisse weiter zu verbessern. Dabei werden vor allem das Probenpräsentationssystem und die Bewertungsmethodik für die empfundene Intensität bei der Bewertung von Bauprodukten gemäß AgBB-Schema betrachtet, da diese einen wesentlichen Einfluss haben.
N2 - Emissions or odours occurring from building products and furnishings for interiors, like floor coverings or wall panels, should not have a negative impact on well-being or health. Odours can be measured applying the standard ISO 16000-28 „Indoor air - Determination of odour emissions from building products using test chambers” It describes among other procedures the assessment of perceived intensi-ty with comparative scale by a group of panellists. In the study presented here, proposals for further technical development of the methodology are discussed to increase the reproducibility of measurement results. The sampling procedure and evaluation method of perceived intensity are investigated in particular because they have a major influence at the assessment of construction products applying the procedure of the Committee for Health Evaluation of Building Products.
KW - Geruchsmessung
KW - Emissionen
KW - Bauprodukte
KW - VOC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527458
UR - http://www.gefahrstoffe.de
SN - 0949-8036
SN - 1436-4891
VL - 81
IS - 3-4
SP - 151
EP - 155
PB - VDI Fachmedien
CY - Düsseldorf
AN - OPUS4-52745
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nordholt, Niclas
A1 - van Heerden, J. H.
A1 - Bruggeman, F. J.
T1 - Biphasic Cell-Size and Growth-Rate Homeostasis by Single Bacillus subtilis Cells
N2 - The growth rate of single bacterial cells is continuously disturbed by random fluctuations in biosynthesis rates and by deterministic cell-cycle events, such as division, genome duplication, and septum formation.
It is not understood whether, and how, bacteria reject these growth-rate disturbances. Here, we quantified growth and constitutive protein expression dynamics of single Bacillus subtilis cells as a function of cell-cycle progression. We found that, even though growth at the population level is exponential, close inspection of the cell cycle of thousands of single Bacillus subtilis cells reveals systematic deviations from exponential growth.
Newborn cells display varying growth rates that depend on their size. When they divide, growth-rate Variation has decreased, and growth rates have become birth size independent. Thus, cells indeed compensate for growth-rate disturbances and achieve growth-rate homeostasis. Protein synthesis and growth of single cells displayed correlated, biphasic dynamics from cell birth to division. During a first phase of variable duration, the absolute rates were approximately constant and cells behaved as sizers. In the second phase, rates increased, and growth behavior exhibited characteristics of a timer strategy. These findings demonstrate that, just like size homeostasis, growth-rate homeostasis is an inherent property of single cells that is achieved by cell-cycle-dependent rate adjustments of biosynthesis and growth.
KW - Bacterial cell cycle
KW - Single cell microbiology
KW - Bacillus subtilis
KW - Growth-rate homeostasis
KW - Biphasic growth
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510689
DO - https://doi.org/10.1016/j.cub.2020.04.030
VL - 30
IS - 12
SP - 2238
EP - 2247
PB - Cell Press
AN - OPUS4-51068
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Kruschwitz, Sabine
A1 - Ebell, Gino
T1 - Datengesteuerte Multisensor-Fusion zur Korrosionsprüfung von Stahlbetonbauteilen
N2 - Potentialfeldmessung (PM) ist die beliebteste Methode der Zerstörungsfreien Prüfung (ZfP) zur Lokalisierung von aktiver Betonstahlkorrosion. PM wird durch Parameter wie z. B. Feuchtigkeits- und Chloridgradienten im Bauteil beeinflusst, so dass die Sensitivität gegenüber der räumlich sehr begrenzten, aber gefährlichen Lochkorrosion gering ist. Wir zeigen in dieser Studie, wie zusätzliche Messinformationen mit Multisensor-Datenfusion genutzt werden können, um die Detektionsleistung zu verbessern und die Auswertung zu automatisieren. Die Fusion basiert auf überwachtem maschinellen Lernen (ÜML). ÜML sind Methoden, die Zusammenhänge in (Sensor-) Daten anhand vorgegebener Kennzeichnungen (Label) erkennen. Wir verwenden ÜML um „defekt“ und „intakt“ gelabelte Bereiche in einem Multisensordatensatz zu unterscheiden. Unser Datensatz besteht aus 18 Messkampagnen und enthält jeweils PM-, Bodenradar-, Mikrowellen-Feuchte- und Wenner-Widerstandsdaten. Exakte Label für veränderliche Umweltbedingungen wurden in einer Versuchsanordnung bestimmt, bei der eine Stahlbetonplatte im Labor kontrolliert und beschleunigt verwittert. Der Verwitterungsfortschritt wurde kontinuierlich überwacht und die Korrosion gezielt erzeugt. Die Detektionsergebnisse werden quantifiziert und statistisch ausgewertet. Die Datenfusion zeigt gegenüber dem besten Einzelverfahren (PM) eine deutliche Verbesserung. Wir beschreiben die Herausforderungen datengesteuerter Ansätze in der zerstörungsfreien Prüfung und zeigen mögliche Lösungsansätze.
T2 - DGZfP Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Maschinelles Lernen
KW - Datenfusion
KW - ZfP
KW - Beton
KW - Korrosion
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444852
UR - http://www.ndt.net/?id=23106
SN - 1435-4934
VL - 23
IS - 9
SP - 1
EP - 9
PB - NDT.net
CY - Kirchwald
AN - OPUS4-44485
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, W.
A1 - Wilsch, Gerd
A1 - Katsumi, N.
A1 - Ebell, Gino
A1 - Völker, Tobias
T1 - Ion distribution in concrete overlay, mapped by laser induced breakdown spectroscopy (LIBS), modified by an embedded zinc anode
N2 - Galvanic corrosion protection by embedded zinc anodes is an accepted technique for the corrosion protection of reinforcing steel in concrete. Galvanic currents flow between the zinc anode and the steel reinforcement due to the potential difference that is in the range of a few hundred mV.
The ion distribution was studied on two steel reinforced concrete specimens admixed with 3 wt.% chloride/wt. cement and galvanically protected by a surface applied EZ-anode. On both specimens, a zinc anode was embedded and glued to the concrete surface by a geo-polymer-based chloride-free binder. At one specimen, the EZ-anode was operated for 2,5 years, the EZ-anode at the other specimen was not electrically connected to the reinforcement, this specimen serves as a reference. Both specimens have been stored under identical conditions. The ion distribution between the anode (EZ-ANODE) and cathode (steel reinforcement) was studied by laser-induced breakdown spectroscopy (LIBS) after 7 months, 12 months, and 2,5 years. Results of the LIBS studies on the specimen with activated EZ-anode after 7 months, 12 months, and 2,5 years and of the reference specimen after 2,5 years are reported. Results show that diffusion of ions contributes to the changes in the ion distribution but migration, especially of chlorides towards the EZ-anode is significant despite the weak electric field – several hundred millivolts - generated by the galvanic current. Results show that chloride ions accumulate near the zinc-anode as in water-insoluble zinc-hydroxy chlorides - Simonkollite.
T2 - ICCRRR 2022
CY - Capetown, South Africa
KW - Corrosion
KW - LIBS
KW - Zinc
KW - Anode
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560576
DO - https://doi.org/10.1051/matecconf/202236404023
SN - 2261-236X
VL - 364
SP - 1
EP - 7
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-56057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Preuß, Bianca
A1 - Lindner, Thomas
A1 - Hanisch, Niclas
A1 - Giese, Marcel
A1 - Schröpfer, Dirk
A1 - Richter, Tim
A1 - Rhode, Michael
A1 - Lampke, Thomas
T1 - Surface Functionalization of Novel Work‐Hardening Multi‐Principal‐Element Alloys by Ultrasonic Assisted Milling
N2 - The development of multi‐principal‐element alloys (MPEAs) with unique characteristics such as high work hardening capacity similar to well‐known alloy systems like Hadfield steel X120Mn12 (ASTM A128) is a promising approach. Hence, by exploiting the core effects of MPEAs, the application range of conventional alloy systems can be extended. In the present study, work‐hardening MPEAs based on the equimolar composition CoFeNi are developed. Mn and C are alloyed in the same ratio as for X120Mn12. The production route consists of cast manufacturing by an electric arc furnace and surface functionalization via mechanical finishing using ultrasonic‐assisted milling (USAM) to initiate work hardening. The microstructure evolution, the hardness as well as the resulting oscillating wear resistance are detected. A pronounced lattice strain and grain refinement due to the plastic deformation during the USAM is recorded for the MPEA CoFeNi‐Mn12C1.2. Consequently, hardness increases by ≈380 HV0.025 in combination with a higher oscillating wear resistance compared to the X120Mn12. This shows the promising approach for developing work‐hardening alloys based on novel alloy concepts such as MPEAs.
KW - Electric arc furnace
KW - Finish milling
KW - High manganese steels
KW - Multi-principal element alloy
KW - Ultrasonic-assisted milling
KW - Work hardening
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608008
DO - https://doi.org/10.1002/adem.202400339
SN - 1438-1656
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-60800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heyn, A.
A1 - Meist, M.
A1 - Michael, O.
A1 - Babutzka, M.
A1 - Valet, Svenja
A1 - Ebell, Gino
T1 - Electrochemical characterization of surfaces of galvanized steels under different exposure conditions using gel electrolytes
N2 - The corrosion behavior of galvanized steels and zinc components under atmospheric exposure depends mostly on the corrosion product‐based cover layer formation under the prevailing conditions. The use of agar‐based gel electrolytes makes it possible to use electrochemical methods to obtain a characteristic value from these cover layers that describe their current and future protective capacity. It is shown here that different states of galvanized steel can be distinguished very well under laboratory conditions and that this method is also suitable for use under practical conditions. Based on the characteristic values and assuming future time of wetness, it is very easy to draw up a forecast for the future corrosion rate, which provides plausible values.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - Environmental Chemistry
KW - Corrosion
KW - Znc
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599234
DO - https://doi.org/10.1002/maco.202414389
SP - 1
EP - 16
PB - Wiley VHC-Verlag
AN - OPUS4-59923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Mente, Tobias
T1 - Trapping and diffusion in high-pressure hydrogen charged CoCrFeMnNi high entropy alloy compared to austenitic steel 316L
N2 - High entropy alloys (HEAs) have attracted considerable research attention as potential substitute materials for austenitic steels in high-pressure hydrogen environments. The corresponding hydrogen absorption, diffusion and trapping has received less scientific attention. Therefore, the CoCrFeMnNi-HEA was investigated and compared to an austenitic steel AISI 316L. Both were subjected to high-pressure hydrogen charging at 200 bar and 1000 bar. Thermal Desorption Analysis (TDA) was used to clarify the specific desorption behavior and hydrogen trapping. For this purpose, the underlying TDA spectra were analyzed in terms of a reasonable peak deconvolution into a defined number of peaks and the activation energies for the respective and predominant hydrogen trapping sites were then calculated. Both materials show comparable hydrogen diffusivity. However, there were significant differences in the absorbed hydrogen concentrations at both charging pressures. The calculated activation energies suggest strong hydrogen trapping in the CoCrFeMnNi-HEA.
KW - High-entropy alloy
KW - Hydrogen diffusion
KW - Trapping
KW - High-pressure charging
KW - Thermal desorption analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611901
DO - https://doi.org/10.1016/j.ijhydene.2024.09.393
SN - 0360-3199
VL - 89
IS - 89
SP - 772
EP - 782
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-61190
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ebell, Gino
A1 - Burkert, Andreas
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Innovative Prüfverfahren für die Korrosionsprüfung von Beton- und Spannstählen
N2 - Innovative Prüfverfahren sind immer dann gefordert, wenn z.B. neue Materialien in etablierte Bauweisen inte- griert werden und deren Mehrwert quantifiziert werden soll. Ebenso kommt es vor, dass bestehende Materia- lien mit aktuellen Prüfverfahren nicht hinreichend differenziert und beschrieben werden können. In beiden Fällen erarbeitet die BAM für den Bereich Korrosion und Korrosionsschutz geeignete Prüfverfahren.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Korrosionsprüfung
KW - Spannstählen
KW - Beton
KW - Korrosion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612972
SN - 978-3-9818564-7-7
SP - 60
EP - 67
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61297
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Ebell, Gino
A1 - Burkert, Andreas
A1 - Breit, W.
A1 - Adams, R.
A1 - Oechsner, M.
A1 - Hoche, H.
A1 - Körber, D.
T1 - Technologie- und Sicherheitszuwachs bei der Anwendung von feuerverzinktem Betonstahl zum Ausbau einer nachhaltigen Marktposition im Stahlbetonbau
N2 - Die Feuerverzinkung von Betonstahl stellt auf der Grundlage der im Stahlbetonbau geltenden Regelwerke eine zusätzliche Maßnahme zur Steigerung der Dauerhaftigkeit insbesondere bei Korrosionsbeanspruchung infolge Karbonatisierung und/oder Chlorideinwirkung dar. Anders als im Ausland ist die Anwendung von feuerverzinktem Betonstahl in Deutschland bisher kaum verbreitet.
Im Rahmen des AiF-Forschungsprojekts IGF 499 „Technologie- und Sicherheitszuwachs bei der Anwendung von feuerverzinktem Betonstahl zum Ausbau einer nachhaltigen Marktposition im Stahlbetonbau“ sollten die einem breiteren Einsatz feuerverzinkter Betonstähle in Deutschland bisher entgegenstehenden offenen Fragestellungen beantwortet werden.
Die interdisziplinäre Forschergruppe bestand aus dem Fachgebiet Werkstoffe im Bauwesen, Technische Universität Kaiserslautern (Forschungsstelle 1), mit dem Arbeitsschwerpunkt Fertigungstechnik, der staatlichen Materialprüfungsanstalt Darmstadt an der Technischen Universität Darmstadt (Forschungsstelle 2), mit dem Arbeitsschwerpunkt Werkstofftechnik, und der Bundesanstalt für Materialforschung und –prüfung, Berlin (Forschungsstelle 3), mit dem Arbeitsschwerpunkt Korrosionsschutz.
KW - Verzinkter Betonstahl
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402215
SP - 1
EP - 253
PB - AiF-Forschungsvereinigung Gemeinschaftsausschuss Verzinken e.V. (GAV)
AN - OPUS4-40221
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Richter, Tim
A1 - Mente, Tobias
A1 - Mayr, P.
A1 - Nitsche, A.
T1 - Thickness and microstructure effect on hydrogen diffusion in creep‑resistant 9% Cr P92 steel and P91 weld metal
N2 - Martensitic 9% Cr steels like P91 and P92 show susceptibility to delayed hydrogen assisted cracking depending on their microstructure. In that connection, effective hydrogen diffusion coefficients are used to assess the possible time-delay. Limited data on room temperature diffusion coefficients reported in literature vary widely by several orders of magnitude (mostly attributed to variation in microstructure). Especially P91 weld metal diffusion coefficients are rare so far. For that reason, electrochemical permeation experiments had been conducted using P92 base metal and P91 weld metal (in as-welded and heat-treated condition) with different thicknesses. From the results obtained, diffusion coefficients were calculated using to different methods, time-lag, and inflection point. Results show that, despite microstructural effects, the sample thickness must be considered as it influences the calculated diffusion coefficients. Finally, the comparison of calculated and measured hydrogen concentrations (determined by carrier gas hot extraction) enables the identification of realistic diffusion coefficients.
KW - Creep-resistant steel
KW - Diffusion
KW - Hydrogen assisted cracking
KW - Welding
KW - Electrochemical permeation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540645
DO - https://doi.org/10.1007/s40194-021-01218-9
SN - 0043-2288
SP - 1
EP - 16
PB - Springer Nature Switzerland AG
AN - OPUS4-54064
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sprachmann, J.
A1 - Grabicki, N.
A1 - Möckel, Anna
A1 - Maltitz, J.
A1 - del Refugio Monroy Gómez, J.
A1 - Smales, Glen Jacob
A1 - Dumele, O.
T1 - Substituted Benzophenone Imines for COF Synthesis via Formal Transimination
N2 - Covalent organic frameworks (COFs) are a prominent class of organic materials constructed from versatile building blocks via reversible reactions. The quality of imine-linked COFs can be improved by using amine monomers protected with benzophenone forming benzophenone imines. Here, we present a study on substituted benzophenones in COF synthesis via formal transimination. 12 para-substituted N-aryl benzophenone imines, with a range of electron-rich to electron-poor substituents, were prepared and their hydrolysis kinetics were studied spectroscopically. All substituted benzophenone imines can be employed in COF synthesis and lead to COFs with high crystallinity and high porosity. The substituents act innocent to COF formation as the substituted benzophenones are cleaved off. Imines can be tailored to their synthetic demands and utilized in COF formation. This concept can make access to previously unattainable, synthetically complex COF monomers feasible.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - General Chemistry
KW - Ceramics and Composites
KW - Electronic, Optical and Magnetic Materials
KW - Catalysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586449
DO - https://doi.org/10.1039/D3CC03735E
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dal Molin, E. S.
A1 - Henning, L. M.
A1 - Müller, J. T.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Bekheet, M. F.
A1 - Gurlo, A.
A1 - Simon, U.
T1 - Robocasting of ordered mesoporous silica‐based monoliths: Rheological, textural, and mechanical characterization
N2 - Hierarchically porous, high‐surface‐area silica materials are excellent candidates for multiple applications like catalysis and environmental remediation. Shaping these materials with additive manufacturing (AM) techniques, like robocasting, could enable their use with the benefit of on‐demand, customized shaping and maximizing performance. Herein, ordered mesoporous silica COK‐12 slurries were robocasted into monoliths, containing different ratios of uncalcined COK‐12 and sodium bentonite (0–25 wt.%). The rheology of the mixed slurries is characterized by lower flow indexes (0.69 vs. 0.32) and higher yield stresses (96 vs. 259 Pa) compared to pure COK‐12 ones. Monoliths were printed in woodpile structures and calcined at 600°C. Micro‐CT measurements showed a linear shrinkage of 25% after calcination. Mechanical characterization showed increased uniaxial strength (0.20 ± 0.07 to 1.0 ± 0.3 MPa) with increasing binder/solids ratio from 13 to 25%. The amorphous, mesoporous structure of COK‐12 was retained. The structures exhibited open porosities of 52 ± 4% and showed higher specific mesopore volumes, and increased average mesopore size (6 vs. 8 nm) compared to COK‐12. Small‐angle x‐ray scattering analysis revealed an increased lattice parameter (10.3 vs. 11.0 nm) and reduced wall thickness (3.1 nm vs. 4.1 nm) of the COK‐12 in the monoliths. These properties indicate suitability for their application as porous supports and adsorbents.
KW - Industrial and Manufacturing Engineering
KW - Additive manufacturing
KW - OMS
KW - Porous materials
KW - Robocasting
KW - X-ray scattering
KW - MOUSE
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582503
DO - https://doi.org/10.1002/nano.202300109
VL - 4
IS - 11-12
SP - 615
EP - 631
PB - Wiley-VCH GmbH
AN - OPUS4-58250
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Foroutan, Farzad
A1 - Abrahams, Isaac
A1 - Smales, Glen Jacob
A1 - Kanwal, Nasima
A1 - di Pasquale, Roberto
A1 - Knowles, Jonathan C.
A1 - Smith, Andrew J.
A1 - Carta, Daniela
T1 - A sol-gel templating route for the synthesis of hierarchical porous calcium phosphate glasses containing zinc
N2 - Hierarchical porous phosphate-based glasses (PPG) have great potential in biomedicine. Micropores (pore size <2 nm) increase the surface area, mesopores (pore size 2–50 nm) facilitate the absorption and diffusion of therapeutic ions and molecules making them ideal controlled delivery systems, while macropores (pore size >50 nm) facilitate the movement and diffusion of cells and fluids. In addition, the bioresorbability of PPG allows for their complete solubility in body fluid, alongside simultaneous formation of new tissue. Making PPG via the traditional melt-quenching (MQ) synthesis method used for phosphate-based glasses (PG), is not straightforward. Hence, we present here a route for preparing such glasses using a combination of sol-gel (SG) and templating methods. Hierarchical PPG in the P₂O₅–CaO–Na₂O system with the addition of 1, 3 and 5 mol % of Zn²⁺ were prepared with pore dimensions ranging from the micro-to the macro scales using Pluronic 123 (P123) as a surfactant. The presence of micropores (0.30–0.46 nm), mesopores (1.75–9.35 nm) and macropores (163–207 nm) was assessed via synchrotron-based Small-Angle X-ray Scattering (SAXS), with the presence of the latter two confirmed by Scanning Electron Microscopy (SEM). Structural characterisation performed using ³¹P solid state magic angle spinning nuclear magnetic resonance (MAS NMR) and Fourier Transform Infrared (FTIR) spectroscopies shows the presence of Q², Q¹ and Q⁰ phosphate species with a predominance of Q¹ species in all compositions. Dissolution studies in deionised (DI) water confirm that controlled release of phosphates, Ca²⁺, Na⁺ and Zn²⁺ is achieved over a period of 7 days. In particular, the release of Zn²⁺ is proportional to its loading, making its delivery particularly easy to control.
KW - Sol-gel
KW - Phosphate-based glasses
KW - Mesoporous materials
KW - Hierarchical porosity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613698
DO - https://doi.org/10.1016/j.ceramint.2024.07.180
SN - 0272-8842
VL - 50
IS - 20, Part A
SP - 38174
EP - 38182
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hayward, E. C.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Takeguchi, M.
A1 - Kulak, A.
A1 - Hunter, R. D.
A1 - Schnepp, Z.
T1 - The effect of catalyst precursors on the mechanism of iron-catalysed graphitization of cellulose
N2 - Iron-catalysed graphitization of biomass is a simple and sustainable route to carbons with high graphitic content. It uses abundant precursors and moderate processing temperatures and generates carbons with high porosity. Recently, it has been demonstrated that the choice of biomass precursor can have a significant impact on the textural and compositional properties of the resulting carbon. In this paper, we demonstrate that the choice of catalyst is also critical to the carbon structure. Aqueous iron(III) nitrate and iron(III) chloride convert cellulose to carbons with very different textural properties. This is due to the choice of iron catalyst changing the mechanism of cellulose decomposition and also the nature of the active graphitization catalyst.
KW - Catalyst
KW - Carbon materials
KW - Cellulose
KW - Small-angle scattering
KW - Green energy
KW - Graphitic carbon
KW - Green synthesis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614800
DO - https://doi.org/10.1039/D4SU00365A
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hallier, Dorothea C.
A1 - Smales, Glen Jacob
A1 - Seitz, H.
A1 - Hahn, Marc Benjamin
T1 - Bio-SAXS of single-stranded DNA-binding proteins: Radiation protection by the compatible solute ectoine
N2 - Small-angle X-ray scattering (SAXS) can be used for structural determination of biological macromolecules and polymers in their native states (e.g. liquid phase). This means that the structural changes of (bio-)polymers, such as proteins and DNA, can be monitored in situ to understand their sensitivity to changes in chemical environments. In an attempt to improve the reliability of such experiments, the reduction of radiation damage occurring from exposure to X-rays is required. One such method, is to use scavenger molecules to protect macromolecules against radicals produced during radiation exposure, such as reactive oxygen species (ROS). In this study we investigate the feasibility of applying the compatible solute, osmolyte and radiation protector Ectoine (THP(B)), as a scavenger molecule during SAXS measurements of the single-stranded DNA-binding protein Gene-V Protein (G5P/GVP). In this case, we monitor the radiation induced changes of G5P during bio-SAXS measurments and the resulting microscopic energy-damage relation was determined from microdosimetric calculations by Monte-Carlo based particle scattering simulations with TOPAS/Geant4 and a custom target-model. This resulted in a median-lethal energy deposit of pure G5P at 4 mg mL−1 of E1/2 = 7 ± 5 eV, whereas a threefold increase of energy-deposit was needed under the presence of Ectoine to reach the same level of damage. This indicates that Ectoine increases the possible exposure time before radiation-damage to G5P is observed. Furthermore, the dominant type of damage shifted from aggregation in pure solutions towards a fragmentation for solutions containing Ectoine as a cosolute. These results are interpreted in terms of indirect radiation damage by reactive secondary species, as well as post-irradiation effects, related to preferential-exclusion of the cosolute from the protein surface. Hence, Ectoine is shown to provide a non-disturbing way to improve structure-determination of proteins via bio-SAXS in future studies.
KW - BioSAXS
KW - Bio-SAXS
KW - Cosolute
KW - Ectoine
KW - G5P
KW - GVP
KW - Radiation damage
KW - Radical Scavenger
KW - Single-stranded DNA-binding proteins
KW - X-ray scattering
KW - DNA
KW - ssDNA
KW - Protein
KW - SAXS
KW - Small-angle xray scattering
KW - McSAS3
KW - Dosimetry
KW - Microdosimetry
KW - Geant4
KW - Geant4-DNA
KW - Topas
KW - Topas-MC
KW - Monte-Carlo simulations
KW - Particle scattering simulations
KW - Topas-nBio
KW - OH Radical
KW - OH radical scavenger
KW - LEE
KW - Ionizing radiation damage
KW - Protein unfolding
KW - Ectoin
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568909
DO - https://doi.org/10.1039/d2cp05053f
SN - 1463-9076
SN - 1463-9084
VL - 25
IS - 7
SP - 5372
EP - 5382
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-56890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hunter, R. D.
A1 - Hayward, E. C.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Kulak, A.
A1 - Guan, S.
A1 - Schnepp, Z.
T1 - The effect of nitrogen on the synthesis of porous carbons by iron-catalyzed graphitization
N2 - This paper reports a systematic study into the effect of nitrogen on iron-catalyzed graphitization of biomass. Chitin, chitosan, N-acetylglucosamine, gelatin and glycine were selected to represent nitrogen-rich saccharides and amino-acid/polypeptide biomass precursors. The materials were pyrolyzed with an iron catalyst to produce carbons with a wide range of chemical and structural features such as mesoporosity and nitrogen-doping. Many authors have reported the synthesis of nitrogen-doped carbons by pyrolysis and these have diverse applications. However, this is the first systematic study of how nitrogen affects pyrolysis of biomass and importantly the catalytic graphitization step. Our data demonstrates that nitrogen inhibits graphitization but that some nitrogen survives the catalytic graphitization process to become incorporated into various chemical environments in the carbon product.
KW - Graphitization
KW - Nanoparticles
KW - Nanocomposite
KW - Porous carbon
KW - Nitrogen
KW - Scattering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575351
DO - https://doi.org/10.1039/d3ma00039g
VL - 4
SP - 2070
EP - 2077
PB - Royal Society of Chemistry
AN - OPUS4-57535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, L. M.
A1 - Smales, Glen Jacob
A1 - Colmenares, M. G.
A1 - Bekheet, M. F.
A1 - Simon, U.
A1 - Gurlo, A.
T1 - Synthesis and properties of COK-12 large-pore mesocellularsilica foam
N2 - Large, ink-bottle-shaped pores in mesocellular foams (MCFs) are desired for various applications requiring enhanced mass transfer or the immobilization of larger compounds. Hence, the cylindrical pores of COK-12, an ordered mesoporous silica structurally comparable to SBA-15 but synthesized at room-temperature at quasi-neutral pH, are chemically swollen into ink-bottle pores. Therefore, p-xylene is used as a more sustainable swelling agent compared to popular alternatives. Its high boiling point allows for an additional thermal aging step to amplify the mesostructure enlargement without needing additional chemicals. For COK-12, the MCFs obtained at room temperature reach an unprecedented plateau for the modal mesopore cell and window diameter of 19.9 and 5.5 nm, respectively, with an underlying broad pore size distribution and distorted hexagonal lattice up to 14.5 nm, involving hexagonal and spherical structures. The combined chemical and thermal swelling resulted in the selective enlargement of the window diameter to more than 200% and a slightly increased cell diameter, pore size distribution, and hexagonal lattice distortion in comparison to the room temperature synthesis. Such materials are thought to be promising alternatives to SBA-15-based MCFs, often utilizing toxic catalysts during synthesis. The presented results pave the way for enhanced adsorptive, catalytic, and drug delivery performances for COK-12-based materials.
KW - SAXS
KW - MOUSE
KW - Mesocellular foam
KW - Mesoporous silica
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569590
DO - https://doi.org/10.1002/nano.202200223
SP - 1
EP - 11
AN - OPUS4-56959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rhode, Michael
A1 - Wetzel, Annica
A1 - Oczan, Ozlem
A1 - Nietzke, Jonathan
A1 - Richter, Tim
A1 - Schröpfer, Dirk
T1 - Hydrogen diffusion and local Volta potential in high- and medium-entropy alloys
N2 - High-entropy alloys (HEAs) are characterized by a solid solution of minimum five and medium-entropy alloys (MEAs) of minimum three principal alloying elements in equiatomic proportions. They show exceptional application properties, such as high-strength and ductility or corrosion resistance. Future HEA/MEA-components could be exposed to hydrogen containing environments like vessels for cryogenic or high-pressure storage where the hydrogen absorption and diffusion in these materials is of interest. In our study, we investigated the HEA Co20Cr20Fe20Mn20Ni20 and the MEA Co33.3Cr33.3Ni33.3. For hydrogen ingress, cathodic charging was applied and diffusion kinetic was measured by high-resolution thermal desorption spectros-copy using different heating rates up to 0.250 K/s. Peak deconvolution resulted in high-temperature desorption peaks and hydrogen trapping above 280 °C. A total hydrogen concentration > 40 ppm was identified for the MEA and > 100 ppm for HEA. This indicates two important effects: (1) delayed hydrogen diffusion and (2) considerable amount of trapped hydrogen that must be anticipated for hydrogen assisted cracking phenomenon. Local electrochemical Volta potential maps had been measured for the hydrogen free condition by means of high-resolution Scanning Kelvin Probe Force Microscopy (SKPFM).
T2 - Symposium on Materials and Joining Technology
CY - Online meeting
DA - 07.09.2020
KW - Hydrogen
KW - High-entropy alloy
KW - Diffusion
KW - Scanning kelvin probe force microscopy
KW - Corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511684
DO - https://doi.org/10.1088/1757-899X/882/1/012015
VL - 882
SP - 1
EP - 15
PB - IOP Publishing
CY - Bristol
AN - OPUS4-51168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
A1 - Börner, Andreas
T1 - Influence of modern machining processes on the surface integrity of high-entropy alloys
N2 - High Entropy Alloys (HEAs) are a recent class of materials. In contrast to conventional alloys, HEAs consist of five alloying elements in equiatomic equilibrium. The high entropy effect is due, among other things, to the increased configuration entropy, which promotes solid solution formation. Many HEAs have enormous application potential due to excellent structural property combinations from very low to high temperatures. For the introduction of HEAs in real components, however, the question of the applicability of machining production technologies for component manufacture is of central importance. This has so far received Little attention in global materials research. Reliable and safe processing is essential for the demand of economical component production for potential areas of application, e.g. in power plant technology.
For metals, milling is the standard machining process. This article presents the results of machining analyses. It focuses on the surface integrity resulting from the milling process on a Co20Cr20Fe20Mn20Ni20-HEA. For this purpose, investigations were carried out using ball nose end milling tools for conventional milling process in comparison to an innovative hybrid process available at BAM Berlin, Ultrasonic-Assisted Milling (USAM). USAM promises a lower Degradation of the surface properties due to lower loads on the workpiece surface during machining.
For this purpose, basic milling parameters (cutting speed and tooth feed) were systematically varied and cutting forces were measured during the milling experiments. The subsequent Analysis of these forces allows an understanding of the mechanical loads acting on the tool and component surface. These loads cause topographical, mechanical and microstructural influences on the surface and consequently on the surface integrity. For their characterization, light and scanning electron microscopy were used, and the roughness and residual stresses via X-ray diffraction were measured. The results indicate significant advantages using USAM, especially due to reduced cutting forces compared to the conventional milling process. This causes lower mechanical loads on the tool and surface, combined with lower tensile residual stresses on and below the surface, and ultimately results in a significantly enhanced surface integrity.
T2 - Symposium on Materials and Joining Magdeburg 2020
CY - Online meeting
DA - 07.09.2020
KW - High entropy alloy
KW - Machining
KW - Ultrasonic machining
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512958
DO - https://doi.org/10.1088/1757-899X/882/1/012016
VL - 882
IS - 012016
SP - 1
EP - 11
PB - Institute of Physics
CY - London
AN - OPUS4-51295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rhode, Michael
A1 - Nietzke, Jonathan
A1 - Richter, Tim
A1 - Mente, Tobias
A1 - Mayr, P
A1 - Nitsche, A
T1 - Hydrogen effect on mechanical properties and cracking of creep‑resistant 9% Cr P92 steel and P91 weld metal
N2 - Martensitic 9% Cr steels like P91 and P92 can show an increased susceptibility to delayed hydrogen-assisted cracking. The focus of this study was the microstructure and heat treatment efect on the mechanical properties of P92 base material and P91 multi-layer weld metal in both as-welded and post weld heat treated (PWHT) condition. Tensile tests with hydrogen free reference samples and electrochemically hydrogen charged samples were carried out; the mechanical properties were assessed and supported by detailed fractographic analysis. Finally, a hydrogen and microstructure-dependent fracture criterion is established. All investigated microstructures showed a hydrogen-infuenced degradation of the mechanical properties compared to the hydrogen-free reference samples. The as-welded martensitic P91 weld metal had the highest degree of degradation in the presence of hydrogen. The P91 PWHT weld metal and the P92 base material had comparable properties. From that point of view, a signifcantly increased risk for hydrogen-assisted cold cracking during welding fabrication of P91 weld joints must be considered before any heat treatment is conducted.
T2 - IIW Annual Assembly, Meeting of Commission IX-C
CY - Tokyo, Japan
DA - 16.07.2022
KW - Creep-resisting materials
KW - Welding
KW - Hydrogen assisted cracking
KW - Hydrogen embrittlement
KW - Mechanical properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564070
DO - https://doi.org/10.1007/s40194-022-01410-5
SN - 0043-2288
SP - 1
EP - 12
PB - Springer Nature
CY - Basel (CH)
AN - OPUS4-56407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buzolin, R. H.
A1 - Richter, Tim
A1 - Pixner, F.
A1 - Rhode, Michael
A1 - Schröpfer, Dirk
A1 - Enzinger, N.
T1 - Microstructure characterisation of multi-principal element alloys welds produced by electron beam welding
N2 - This work explores the feasibility of producing bead-on-plate welds of a CrCoNi medium entropy alloy and a CrMnFeCoNi high entropy alloy using electron beam welding. The alloys were welded in two states: one in an as-cold-rolled condition and the other in an annealed condition. In addition, the materials are welded with two different parameters. The FCC microstructure of the welds is investigated using scanning electron microscopy assisted by energy-dispersive X-ray spectroscopy and electron-backscattered diffraction. The impact of the weld on the microstructure is discussed. The heat-affected zone is negligible for the annealed condition of both medium and high entropy alloys since there is no driving force for recrystallisation and the exposure time to high temperature is insufficient for grain coarsening. The texture formed in the fusion zone is also discussed and compared to the texture in the base metal and the heat-affected zone. Although the grain growth along the (100) crystallographic direction is preferential in all cases, the crystallographic texture type differs from each weld. Higher hardness values are measured in the medium entropy alloy’s base metal and fusion zone than in the high entropy alloy.
KW - Multi-principal element alloy
KW - Electron backscattered diffraction
KW - Electron beam welding
KW - High-entropy alloy
KW - Microstructure characterization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568129
DO - https://doi.org/10.1016/j.matdes.2023.111609
SN - 1873-4197
VL - 225
SP - 1
EP - 14
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-56812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Tim
A1 - Schröpfer, Dirk
A1 - Rhode, Michael
T1 - Residual stresses in a high- and a medium-entropy alloy due to TIG and friction stir welding
N2 - The new alloying concept of multi-element systems with defined entropy (HEA—high-entropy alloy; MEA—medium-entropy alloy) is gaining increasing importance in materials research. Significantly improved properties or combinations of properties are shown by some HEA/MEA systems. Thus, primarily the production and resulting microstructures of HEA, as well as its properties, have been investigated so far. Furthermore, processing is a main issue in transferring HEA systems from the laboratory to real components. Since welding is the most important joining process for metals, it is crucial to investigate the influence of welding to guarantee component integrity. Welding leads to residual stresses, which significantly affect the component integrity. Hence, the focus of this study is the residual stress formation and distribution in a CoCrFeMnNi HEA and ternary CoCrNi MEA using two different welding processes: tungsten inert gas (TIG) welding and solid-state friction stir welding (FSW). As a pathway for the application of HEA in this investigation, for the first time, residual stress analyses in realistic near-component specimens were performed. The residual stresses were determined by X-ray diffraction (XRD) on the surfaces of top and root weld side. The results were correlated with the local welding microstructures. The results show that both FSW and TIG generate significant tensile residual stresses on the weld surfaces in, and transverse to, the welding direction. In the case of FSW of the CoCrFeMnNi HEA, the longitudinal residual stresses are in the range of the yield strength of approx. 260 MPa in the weld zone.
KW - High entropy alloy
KW - Welding
KW - Residual stresses
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567039
DO - https://doi.org/10.3390/jmmp6060147
SN - 2504-4494
VL - 6
IS - 6
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-56703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Monroy, José del Refugio
A1 - Deshpande, Tejas
A1 - Schlecht, Joël
A1 - Douglas, Clara
A1 - Stirling, Robbie
A1 - Grabicki, Niklas
A1 - Smales, Glen Jacob
A1 - Kochovski, Zdravko
A1 - Fabozzi, Filippo Giovanni
A1 - Hecht, Stefan
A1 - Feldmann, Sascha
A1 - Dumele, Oliver
T1 - Homochiral versus racemic 2D covalent organic frameworks
N2 - The synthesis of homochiral two-dimensional covalent organic frameworks (2D COFs) from chiral π-conjugated building blocks is challenging, as chiral units often lead to misaligned stacking interactions. In this work, we introduce helical chirality into 2D COFs using configurationally stable enantiopure and racemic [5]helicenes as linkers in the backbone of 2D [5]HeliCOFs as powders and films. Through condensation with 1,3,5-triformylbenzene (TFB) or 1,3,5-triformylphloroglucinol (TFP), our approach enables the efficient formation of a set of homochiral and racemic 2D [5]HeliCOFs. The resulting carbon-based crystalline and porous frameworks exhibit distinct structural features and different properties between homochiral and racemic counterparts. Propagation of helical chirality into the backbone of the crystalline frameworks leads to the observation of advanced chiroptical properties in the far-red visible spectrum, along with a less compact structure compared with the racemic frameworks. Homogeneous thin films of [5]HeliCOFs disclosed photoluminescent properties arising from the controlled growth of highly ordered π-conjugated lattices. The present study offers insight into general chiral framework formation and extends the Liebisch−Wallach rule to 2D COFs.
KW - Chirality
KW - Covalent organic frameworks
KW - Diffraction
KW - Lattices
KW - Thin films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633755
DO - https://doi.org/10.1021/jacs.5c01004
SN - 0002-7863
VL - 147
IS - 21
SP - 17750
EP - 17763
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-63375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Boschmann Käthler, C.
A1 - Ebell, Gino
A1 - Keßler, S.
A1 - Schiegg, Y.
A1 - Dauberschmidt, C.
A1 - Angst, U. M.
T1 - A comparison of methods to assess the resistance of reinforcing steel against chloride‐induced corrosion in concrete - Particular consideration of 12% chromium steel
N2 - The critical chloride content Ccrit is an indicator of the corrosion resistance of reinforcing steels in concrete. In this article, several experimental methods for determining the critical chloride content Ccrit of mild and alloyed (12% Cr) steel in cementitious materials are compared. The methods used include accelerated polarization tests and tests employing more natural (unpolarized) conditions in which chloride ingress occurs by diffusion and capillary uptake. The advantages and disadvantages of the methods are discussed, in particular, against the objective of reaching a compromise between applicability to practice and feasibility in laboratory testing.
KW - Chloride‐induced corrosion
KW - Critical chloride content
KW - Reinforced concrete
KW - Testing methods
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628485
DO - https://doi.org/10.1002/maco.202112826
SN - 0947-5117
VL - 73
IS - 3
SP - 306
EP - 325
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-62848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ebell, Gino
A1 - Tannert, S.
A1 - Lehmann, Jens
A1 - Müller, H.
T1 - Offshore Weathering Campaign on a North Sea Wind Farm Part One: Corrosivity Categories
N2 - The aim of this study is to investigate the corrosion behavior of materials and coatings in offshore environments, with a focus on determining the corrosivity categories at different locations on wind turbines. The collaboration between the authors enabled a 3‐year weathering campaign at the Hohe See and Albatros offshore wind farms in the North Sea. Metal panels were installed on two wind turbines to assess the corrosivity of different atmospheric conditions. Preliminary results indicate significant variations in corrosivity depending on location and material used, suggesting that current standards may not fully reflect real‐world conditions. The results of the study will help to optimize material selection and corrosion protection strategies for offshore wind farms, potentially extending their lifetime and reducing operating costs.
KW - Corrosion
KW - Offshore
KW - Wind
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628995
DO - https://doi.org/10.1002/maco.202414711
SN - 1521-4176
SP - 1
EP - 10
PB - Wiley
CY - Weinheim
AN - OPUS4-62899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aliyah, K.
A1 - Prehal, C.
A1 - Diercks, J. S.
A1 - Diklić, N.
A1 - Xu, L.
A1 - Ünsal, S.
A1 - Appel, C.
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Guizar-Sicairos, M.
A1 - Herranz, J.
A1 - Gubler, L.
A1 - Büchi, F. N.
A1 - Eller, J.
T1 - Quantification of PEFC Catalyst Layer Saturation via In Silico, Ex Situ, and In Situ Small-Angle X-ray Scattering
N2 - The complex nature of liquid water saturation of polymer electrolyte fuel cell (PEFC) catalyst layers (CLs) greatly affects the device performance. To investigate this problem, we present a method to quantify the presence of liquid water in a PEFC CL using small-angle X-ray scattering (SAXS). This method leverages the differences in electron densities between the solid catalyst matrix and the liquid water filled pores of the CL under both dry and wet conditions. This approach is validated using ex situ wetting experiments, which aid the study of the transient saturation of a CL in a flow cell configuration in situ. The azimuthally integrated scattering data are fitted using 3D morphology models of the CL under dry conditions. Different wetting scenarios are realized in silico, and the corresponding SAXS data are numerically simulated by a direct 3D Fourier transformation. The simulated SAXS profiles of the different wetting scenarios are used to interpret the measured SAXS data which allows the derivation of the most probable wetting mechanism within a flow cell electrode.
KW - Polymer electrolyte fuel cell
KW - Water management
KW - Catalyst layer
KW - Representative morphology modeling
KW - Small-angle X-ray scattering
KW - MOUSE
KW - SAXS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575973
DO - https://doi.org/10.1021/acsami.3c00420
SN - 1944-8244
VL - 15
IS - 22
SP - 26538
EP - 26553
PB - ACS Publications
AN - OPUS4-57597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, Daniel
A1 - Bertovic, Marija
T1 - Expertise oder KI – Was hilft uns in der ZfP'?
N2 - Die zunehmende Integration von Automatisierung und KI in die zerstörungsfreie Prüfung (ZfP) verändert nicht nur die Prüfprozesse selbst, sondern auch die Art und Weise, wie Entscheidungen getroffen werden. Während technische Systeme die Fehleranfälligkeit verringern und die Datenverarbeitung unterstützen können, bleibt die letztendliche Verantwortung beim Menschen. Dieser Beitrag untersucht die Rolle der Intuition in der Entscheidungsfindung und analysiert typische Fehleinschätzungen mithilfe der Prospekttheorie und Erkenntnissen aus der kognitiven Psychologie. Zudem wird aufgezeigt, wie fundierte Entscheidungen in KI-gestützten ZfP Prozessen unterstützt werden können – durch Schulung, erklärbare Systeme, nutzerzentrierte Gestaltung, geeignete Metriken und eine gezielte Aufgabenverteilung zwischen Mensch und Technik.
T2 - DGZfP-Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - Zerstörungsfreie Prüfung
KW - Künstliche Intelligenz
KW - Entscheidungsfindung
KW - Mensch-Maschine-Interaktion
KW - Human Factors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634070
DO - https://doi.org/10.58286/31237
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-63407
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tamburini, Federica
A1 - Kluge, Martin
A1 - Habib, Abdel Karim
A1 - Ustolin, Federico
A1 - Cozzani, Valerio
A1 - Paltrinieri, Nicola
T1 - Exploring experimental tests concerning liquid hydrogen releases
N2 - In recent years, the adoption of liquid hydrogen (LH2) has increased significantly in industrial and transport applications, driven by its low carbon footprint, thereby aiding the fight against global warming. Additionally, its high volumetric energy density, compared to gaseous or compressed hydrogen, enhances hydrogen storage capabilities.
However, safety remains a major concern due to its physical-chemical properties and inherent hazardous characteristics, especially in the event of spillage scenarios. Therefore, to better understand the consequences of LH2 releases onto or into water, large-scale experimental tests were conducted by Bundesanstalt für Materialforschung und -prüfung (BAM) within the Safe Hydrogen Fuel Handling and Use for Efficient Implementation (SH2IFT) project at the Test Site Technical Safety of BAM, comprising 75 single spill events at varied release rates and orientations. While the rapid phase transition (RPT) phenomenon was not observed, selfignition of the hydrogen-air cloud occurred, accompanied by blast wave overpressure and heat radiation, without a discernible ignition source. These findings emphasize the need for further investigation into LH2 safety. Leveraging experimental data for real-world applications provides insights into safe LH2 infrastructure implementation, laying foundational knowledge for addressing safety challenges and advancing LH2 technology.
KW - Liquid Hydrogen
KW - Rapid phase transition
KW - Ignition
KW - Safety
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618644
DO - https://doi.org/10.1016/j.psep.2024.11.014
SN - 0957-5820
VL - 192
SP - 1330
EP - 1343
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lucka, R.
A1 - Elshani, B.
A1 - Kilic, M. S.
A1 - Klimke, S.
A1 - Krüger, C.
A1 - Menzel, Michael
A1 - Stößer, R.
A1 - Titiš, J.
A1 - Boča, R.
A1 - Renz, F.
T1 - ESR and Mössbauer spectroscopy of iron(III) spin crossover complexes based on pentadentate Schiff base ligands with pseudohalide coligands
N2 - Two iron(III) spin crossover complexes [Fe(5Cl-L)(NCS)] (1) and [Fe(5Cl-L)(NCSe)] (2) were synthesized with the pentadentate Schiff base ligand 5Cl-L and thiocyanato and selenocyanato as coligands. 5Cl-L, as an asymmetric {N3O2} donor Schiff base, was synthesized by a condensation reaction of 5-chlorosalicyladehyde using the asymmetric N-(2-aminoethyl)-1,3-propanediamine. The complexes exhibited a spin crossover at 280 (1) and 293 K (2), respectively, and were subjected to electron spin resonance (ESR) and Mössbauer spectroscopy at 77, 295 and 325 K. Ab initio CASSCF calculations followed by the NEVPT2 method were applied for predicting the g-tensor components as well as Mössbauer parameters.
KW - Spin crossover
KW - Iron(III) complexes
KW - Mössbauer spectroscopy
KW - ESR spectroscopy
KW - Ab initio calculations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634061
DO - https://doi.org/10.3390/magnetochemistry11050043
SN - 2312-7481
VL - 11
IS - 5
SP - 1
EP - 9
PB - MDPI
CY - Basel
AN - OPUS4-63406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
ED - Hahn, Oliver
ED - Doil, Thorsten
T1 - Workshop Kulturguterhaltung - Vom Dampfkessel zu Nanomaterialien
N2 - Sehr geehrte Damen und Herren,
liebe Leserinnen und Leser,
bereits im ersten Band der N.i.Ke. Schriftenreihe des Netzwerks zur interdisziplinären Kulturerhaltung hatte ich angeführt, dass bei der Untersuchung von kulturellen Artefakten naturwissenschaftliche Untersuchungsmethoden zunehmend an Bedeutung gewinnen, sie eigentlich unverzichtbar geworden sind.
Ein besonders einprägsames Beispiel dieser fächerübergreifenden Zusammenarbeit zwischen Geisteswissenschaften, Naturwissenschaften und Restaurierungswissenschaften war die Ausstellung Johannes Vermeer. Vom Innehalten, die in diesem Jahr in der Gemäldegalerie Alter Meister in den staatlichen Kunstsammlungen Dresden gezeigt wurde. Eigens für diese Ausstellung wurde das Gemälde Brieflesendes Mädchen am offenen Fenster einer grundlegenden Restaurierung unterzogen. Diese Restaurierung diente jedoch nicht nur der Reparatur des Bildes. Um sich dem ursprünglichen Zustand des Gemäldes zwischen 1657 und 1659 anzunähern, wurden später hinzugefügte Malschichten großflächig abgenommen. Möglich wurde dies durch unterschiedliche, bildgebende materialwissenschaftliche Untersuchungen im Vorfeld, welche die wissenschaftlichen Grundlagen für die Diskussion über den weiteren Umgang mit der Lesenden schufen.
Materialanalytische Verfahren wurden und werden ständig weiterentwickelt und optimiert. Sei es, um aus einer Vielzahl von Einzelmessungen ein Gesamtbild zu erstellen, oder die Größe einer Probenentnahme so zu reduzieren, dass von einer „minimal-invasiven“ oder „quasi nicht-invasiven“ Untersuchung ausgegangen werden kann. Nun feiert die Bundesanstalt für Materialforschung und -prüfung, zusammen mit ihren Vorgängerinstitutionen, den königlichen Versuchsanstalten, in diesem Jahr ihren einhundertfünfzigsten Geburtstag. Sie blickt damit auf eine lange Tradition materialwissenschaftlicher Analysen zurück, an deren Beginn beispielsweise die metallographischen Untersuchungen von Adolf Martens stehen. Derartige Untersuchungen bilden auch heute noch einen wesentlichen Bestandteil archäometallurgischer Forschung. Die Historie bzw. die Weiterentwicklung der Methodik lässt sich hier besonders gut nachzeichnen. Jedoch blicken auch Verfahren zur Charakterisierung weiterer Werkstoffe, wie Glas, Keramik, oder organischer Materialien auf eine lange Geschichte zurück.
Die in diesem Band der N.i.Ke.-Schriftenreihe präsentierten Beiträge dokumentieren einerseits aktuelle Forschungsarbeiten, die erst in diesem Jahr in entsprechenden Fachjournalen publiziert wurden, andererseits liegen einige der Arbeiten bereits 50 Jahre zurück. Sie bekunden damit nicht nur die materialtechnologische und historische Bandbreite der Projekte, sondern offenbaren die Vielfältigkeit kulturhistorischer oder restauratorischer Fragestellungen, zu deren Beantwortung natur- und materialwissenschaftliche Forschung wesentliche Beiträge liefern können.
Ich bedanke mich bei allen Kolleginnen und Kollegen, die zur Erstellung dieser dritten Ausgabe der N.i.Ke. Schriftenreihe des Netzwerks zur interdisziplinären Kulturerhaltung beigetragen haben. Ihre Aufsätze ermöglichen den Blick in die Vielfältigkeit materialwissenschaftlicher Untersuchungen im Bereich Kunst- und Kulturgut. Ich wünsche Ihnen viel Spaß auf dieser kleinen Zeitreise.
T2 - Workshop Kulturguterhaltung - Vom Dampfkessel zu Nanomaterialien
CY - Berlin, Germany
DA - 17.11.2021
KW - Pergamonmuseums
KW - Schriftrollen vom Toten Meer
KW - Gold mit Synchrotronstrahlung
KW - Kandelaber des Ensembles am Charlottenburger Tor
KW - Berliner Tuffsteinfassaden
KW - Betondickglasfenster des Glockenturms am Eiermannbau
KW - Kaiser-Wilhelm-Gedächtniskirche
KW - Radiografische Untersuchung
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543239
UR - https://netzwerke.bam.de/Netzwerke/Navigation/DE/Netzwerke/NIKE/nike.html
VL - 3
SP - 1
EP - 155
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-54323
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Diana
A1 - Hahn, Oliver
ED - Lois, C.
T1 - Colours on East Asian Maps
N2 - Maps and colours have a close connection. Drawn or printed in black on white, subsequently added colours enhance maps with additional information. Colours were not just there to improve maps aesthetically, but they regulated how they were read and thus reinforced their meanings, significances and ideas. Colour is an important key to a more precise understanding of the map’s purposes and uses; moreover, colours are also an important aspect of a map’s materiality. The material scientific analysis makes it possible to find out more about the making of colours and the process of colouring maps. By skillfully deploying colours, map colourists were able to create mimetic representations of nature or codify information in an abstract form. The use of colours involved many considerations as to the materials. ‘Reading’ colours in this way gives a glimpse into the social lives of mapmakers as well as map users and reveals the complexity of the historical and social context in which maps were produced and how the maps were actually made. Within the scope of the three-year joint research project Coloured Maps (2018–2021), we undertook an in-depth and systematic study of hand-drawn and hand-coloured maps from East Asia in the Museum am Rothenbaum (MARKK) in Hamburg and produced between the seventeenth and twentieth centuries.
With a multi-perspective approach and transdisciplinary methods (humanities and the sciences), we were able to pool and compare the research results from different fields of research on Asian maps. The aim of this publication is to provide a first general overview of the subject of colours on maps in East Asia in the period from the seventeenth to the early twentieth century and to stimulate further research on the topic.
KW - Maps and colours
KW - Colouring
KW - Colourants
KW - Dyes and pigments
KW - Map production and publishing
KW - Non-invasive scientific methods
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569682
UR - https://brill.com/display/title/61839
SN - 978-90-04-54562-5
VL - 2023
SP - 1
EP - 79
PB - Brill
CY - Leiden, Netherlands
AN - OPUS4-56968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hahn, Oliver
A1 - Nöller, Renate
ED - Bausi, A.
T1 - Pigments and dyes
N2 - The present volume is the main achievement of the Research Networking Programme ‘Comparative Oriental Manuscript Studies’, funded by the European Science Foundation in the years 2009–2014. It is the first attempt to introduce a wide audience to the entirety of the manuscript cultures of the Mediterranean East.
The chapters reflect the state of the art in such fields as codicology, palaeography, textual criticism and text editing, cataloguing, and manuscript conservation as applied to a wide array of language traditions including Arabic, Armenian, Avestan, Caucasian Albanian, Christian Palestinian Aramaic, Coptic, Ethiopic, Georgian, Greek, Hebrew, Persian, Slavonic, Syriac, and Turkish.
Seventy-seven scholars from twenty-one countries joined their efforts to produce the handbook. The resulting reference work can be recommended both to scholars and students of classical and oriental studies and to all those involved in manuscript research, digital humanities, and preservation of cultural heritage.
The volume includes maps, illustrations, indexes, and an extensive bibliography.
KW - Pigments
KW - Dyes
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447833
UR - https://www.aai.uni-hamburg.de/en/comst/publications/handbook.html
SN - 978-3-7323-1768-4
SN - 978-3-7323-1769-1
SN - 978-3-7323-1770-7
DO - https://doi.org/10.5281/zenodo.46784
SP - 75
EP - 77
PB - European Science Foundation
CY - Hamburg
AN - OPUS4-44783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Hahn, Oliver
A1 - Golle, U.
A1 - Wintermann, Carsten
A1 - Laurenza, D.
ED - Quenzer, J. B.
T1 - Scientific Analysis of Leonardo’s Manuscript with Anatomic Drawings and Notes
N2 - In this paper, we discuss the importance of scientifically investigating cultural artefacts in a non-invasive way. Taking as test case Leonardo da Vinci’s Manuscript with anatomic drawings and notes, which is stored in Weimar, we clarify fundamental steps in the chronology of this folio. By means of microscopy, infrared reflectography, UV photography, and X-ray fluorescence analysis, we were able to identify various types of sketching material and several varieties of iron gall ink. For his sketches, Leonardo used two different sketching tools, a lead pencil and a graphite pencil, as well as several types of ink for developing these sketches into drawings. With regard to ink, it is important to observe that there is no difference between the ink Leonardo used for drawing and the ink he used for writing text. Based on the materials analysed, we suggest a chronology for the creation of this unique folio.
KW - Archaeometry
KW - Non-invasive analysis
KW - Drawings
KW - Leonardo da Vinci
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543460
SN - 978-3-11-074545-0
DO - https://doi.org/10.1515/9783110753301-011
VL - 25
SP - 213
EP - 228
PB - Walter de Gruyter GmbH
CY - Berlin/Boston
AN - OPUS4-54346
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gerards-Wünsche, Paul
A1 - Hille, Falk
T1 - Zuverlässigkeitsbasierter Technologietransfer am Beispiel Risslumineszenz Von der ZfP im Labor zum KI-basierten SHM-System für die Industrie – Statusbericht
N2 - Der Übergang neuer zerstörungsfreien Prüfmethoden (ZfP) aus dem Labor in die industrielle Anwendung stellt erhebliche Herausforderungen dar. Für visuelle ZfP-Techniken, wie die in dieser Studie verwendete Risslumineszenz-Methode, ist die Automatisierung der Fehlererkennung durch KI-gestützte Computer-Vision-Systeme ein logischer nächster Schritt. Findet dies als kontinuierliche Überwachung statt, entwickeln sich solche Systeme zu einer KI-gestützten SHM-Methode. Die Implementierung dieser Technologien in sicherheitskritischen Anwendungen erfordert jedoch einen robusten Nachweis ihrer Zuverlässigkeit, der durch diese Weiterentwicklung an Komplexität gewinnt. Während etablierte Standards für Probability of Detection (POD)-Studien in ZfP-Systemen existieren, fehlen entsprechende Normen für SHM-Systeme, insbesondere solche, die KI einsetzen. Obwohl statistische Methoden für SHM-Systeme verfügbar sind, um Datenabhängigkeiten zu berücksichtigen, ist ein ganzheitlicher POD-Ansatz notwendig, um beeinflussende und variable Störfaktoren umfassend zu adressieren und die Alterung des SHM-Systems zu berücksichtigen.
Diese Arbeit demonstriert Fortschritte bei der Entwicklung einer maßgeschneiderten Methodik, die auf die spezifischen Anforderungen zugeschnitten ist, um die Zuverlässigkeit eines KI-gestützten SHM-Systems auf Basis der Risslumineszenz nachzuweisen. Dieser Ansatz integriert die Prinzipien von POD-Studien mit statistischen Methoden für SHM-Systeme, um eine robuste Zuverlässigkeitsbewertung zu gewährleisten. Er verdeutlicht die erheblichen Herausforderungen, die bereits bei der kontinuierlichen Überwachung einer relativ einfachen visuellen Methode wie der Risslumineszenz auftreten.
T2 - DGZfP-Jahrestagung 2025
CY - Berlin, Germany
DA - 25.05.2025
KW - Risslumineszenz
KW - SHM
KW - PoD
KW - Zuverlässigkeit
KW - ZfP
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636142
SP - 1
EP - 13
PB - NDT.net
AN - OPUS4-63614
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gordon, Nehemia
A1 - Patrick, Andrist
A1 - Hahn, Oliver
A1 - Vasileiadis, Pavlos D.
A1 - Calvillo, Nelson
A1 - Rabin, Ira
T1 - Did the Original Scribes Write the Distigmai in Codex Vaticanus B of the Bible (Vat. gr. 1209)?
N2 - The fourth-century Greek Bible manuscript Codex Vaticanus B (Vat. gr. 1209) contains pairs of horizontally aligned marginal dots known as distigmai, which correspond to textual variants in other manuscripts. The production of the distigmai has been variously dated to the 4th or 16th centuries. A fourth-century date would prove the early existence of hundreds of textual variants, many of which are otherwise only witnessed by later manuscripts. Near infrared microscope reflectography combined with micro-X-ray fluorescence spectroscopy proved that the distigmai, both those categorized as “apricot” (which are visually similar to the ink of the original main text) and “chocolate” (which are visually similar to the reinking of the main text) were written with ink(s) made from chemically purified vitriol, a process that only became standard in the 16th century. As a result, there is no reasonable chance that the distigmai were written in the fourth century. Horizontal lines that have been hypothesized to function as text-critical obeloi were written in the same ink as the original main text, which differs completely from that of the distigmai. In other words, the distigmai and horizontal lines tested were not produced during the same writing session and are separated by more than 1,000 years, making it impossible for them to have functioned as conjoining text-critical symbols in the 4th century.
KW - Bible manuscripts
KW - New Testament
KW - Paratextual features
KW - Textual criticism
KW - Obelos
KW - Septuagint
KW - XRF
KW - Greek palaeography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622902
DO - https://doi.org/10.1163/27728641-00302005
SN - 2772-8633
VL - 3
IS - 2
SP - 125
EP - 156
PB - Brill
CY - Leiden
AN - OPUS4-62290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Colini, Claudia
A1 - Shevchuk, I.
A1 - Huskin, K. A.
A1 - Rabin, Ira
A1 - Hahn, Oliver
ED - Quenzer, J. B.
T1 - A New Standard Protocol for Identification of Writing Media
N2 - Our standard protocol for the characterisation of writing materials within advanced manuscript studies has been successfully used to investigate manuscripts written with a pure ink on a homogeneous writing surface. However, this protocol is inadequate for analysing documents penned in mixed inks. We present here the advantages and limitations of the improved version of the protocol, which now includes imaging further into the infrared region (1100−1700 nm).
KW - Archaeometry
KW - Manuscripts
KW - Non-destructive testing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543454
SN - 978-3-11-074545-0
DO - https://doi.org/10.1515/9783110753301-009
VL - 25
SP - 161
EP - 182
PB - Walter de Gruyter GmbH
CY - Berlin/Boston
AN - OPUS4-54345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Viscous crack healing in soda–lime–magnesium–silicate–ZrO2 glass matrix composites
N2 - AbstractThe present study investigates the influence of the crystal volume content on viscous crack healing in glass ceramic glass sealants. To ensure constant microstructure during healing, soda–lime–magnesium silicate glass matrix composites with varied volume fractions of ZrO2 filler particles were used. Crack healing was studied on radial cracks induced by Vickers indentation, which were stepwise annealed to monitor the healing progress by confocal laser scanning microscopy. Confirming previous studies, healing of radial cracks in pure glass was found delayed by global flow phenomena like crack widening and crack edge and tip rounding to minimize the sample surface. With increasing ZrO2 filler content, these global flow phenomena were progressively inhibited whereas local flow phenomena like sharp crack tip healing could still occur. As a result, crack healing was even accelerated by filler particles up to a maximum filler content of 17 vol% whereas crack healing was fully suppressed only at 33 vol% filler content.
KW - Crack healing
KW - Glass matrix composite
KW - Solid oxide fuell cell
KW - Vickers identation
KW - Viscosity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607860
DO - https://doi.org/10.1111/jace.20002
SN - 0002-7820
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-60786
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gogula, Shravya
A1 - Bornhöft, H.
A1 - Wondraczek, L.
A1 - Sierka, M.
A1 - Diegeler, A.
A1 - Müller, Ralf
A1 - Deubener, J.
T1 - Optical Real-Time Castability Evaluation for High-Throughput Glass Melting
N2 - A novel optical real-time method for evaluating the castability of glass forming melts for laboratory furnaces is presented. The method is based on the analysis of top view images of the melt surface inside the crucible during melting after being subjected to a small mechanical impulse. In this way, the melt surface is excited to oscillate. The difference in contrast between two images taken in quick succession scales with the viscosity, with a larger difference occurring at lower viscosities. The method is designed as an instrument for the in-line evaluation of the castability for a high-throughput glass melting system as part of the joint project “GlasDigital” in the framework of the German Platform Material Digital initiative but is applicable to other laboratory furnaces as well.
KW - Optical Real-Time Castability Check
KW - Image Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618659
DO - https://doi.org/10.52825/glass-europe.v2i.1359
VL - 2
SP - 83
EP - 93
AN - OPUS4-61865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Heimann, Jan
A1 - Duffner, Eric
A1 - Charmi, Amir
A1 - Schukar, Marcus
A1 - Hashemi, Seyedreza
A1 - Prager, Jens
T1 - Towards predictive maintenance of hydrogen pressure vessels based on multi-sensor data
N2 - In this paper, we report on a sensor network for structural health monitoring (SHM) of Type IV composite overwrapped pressure vessels (COPVs) designed for hydrogen storage. The sensor network consists of three different SHM sensing technologies: ultrasonic guided waves (GW), acoustic emission (AE) testing, and distributed fiber optic sensors (DFOS). We present an experimental setup for a lifetime test, where a COPV is subjected to cyclic loading. Data from all sensors are collected and centrally evaluated. The COPV failed after approximately 60,000 load cycles, and the sensor network proved capable of detecting and localizing the damage even before the failure of the COPV. This multi-sensor approach offers significantly more channels of information and could therefore enable a transition from costly and time-consuming periodic inspections to more efficient and modern predictive maintenance strategies, including artificial intelligence (AI)-based evaluation. This not only has a positive effect on operational c
KW - Ffiber optic sensors
KW - Acoustic emission
KW - Guided waves
KW - Hydrogen
KW - Digital twin
KW - Structural health monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618948
DO - https://doi.org/10.58286/30513
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-61894
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wosniok, Aleksander
A1 - Schukar, Marcus
A1 - Woody, Paul
A1 - Wang, Bin
A1 - Breithaupt, Mathias
A1 - Kriegsmann, Andreas
T1 - Distributed fiber optic strain sensing for structural health monitoring of 70 MPa hydrogen vessels
N2 - We report on the development and testing of 70 MPa hydrogen pressure vessels with integrated fiber optic sensing fibers for automotive use. The paper deals with the condition monitoring of such composite pressure vessels (CPVs) using the optical backscatter reflectometry (OBR) applied for a distributed fiber optic strain sensing along fully integrated polyimide-coated single-mode glass optical fiber (SM-GOF). The sensing fibers were embedded into the vessel structure by wrapping them over the polymer liner during the manufacturing process of the carbon fiber reinforced polymer (CFRP). Detecting local strain events by the integrated fiber optic sensors can be an opportunity for monitoring the material degradation of CPVs under static and cyclic loading.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Fiber optic sensor
KW - Distributed strain sensing
KW - Composite pressure vessel
KW - Structural health monitoring
KW - Fiber-reinforced plastics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603105
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-60310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Schukar, Marcus
T1 - Humidity response of optical fibres with hygroscopic coatings and its temperature dependence
N2 - Optical fibres with hygroscopic coatings are widely used in structural health monitoring to acquire the humidity information. Water absorption-induced coating expansion leads to a strain change in the silica fibre, which can be measured by point and distributed strain fibre sensors and used to quantify the environmental humidity. In this paper, the strain transfer from the coating to the fibre is described by both 1D and 3D models. The impact of the coating property on the humidity induced strain is theoretically analysed. Since the properties of the sensing fibre are temperature-dependent, the humidity response obtained by the strain-based approach may change under different thermal conditions. The humidity response of fibres with different polyimide coatings is characterized by a commercial optical frequency domain reflectometer under different temperature conditions. The experimental results confirm the temperature dependence of the humidity response as the sensitivity of all the tested fibres decreases as the temperature increases.
KW - Rayleigh scattering
KW - Humidity sensor
KW - Optical fibre sensors
KW - Optical frequency domain reflectometer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629735
DO - https://doi.org/10.1088/2515-7647/adc85f
VL - 7
IS - 2
SP - 1
EP - 11
PB - IOP Publishing Ltd
CY - Bristol, UK
AN - OPUS4-62973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karapanagiotis, Christos
A1 - Schukar, Marcus
A1 - Breithaupt, Mathias
A1 - Hicke, Konstantin
T1 - Toward a Digital Twin of Hydrogen Pressure Vessels Enabled by Distributed Fiber Optic Sensors
N2 - We present a digital replica of a hydrogen pressure vessel enabled by distributed fiber optic sensors (DFOS). This digital replica dynamically displays and updates the vessel’s structural condition by calculating strain residuals defined as the difference between the measured DFOS strain and the expected strain based on pressure data. As an example, we show the ability of the DFOS to detect and localize damage caused by drilling six holes into the vessel’s body. This digital replica represents a foundational step toward a fully integrated digital twin for predictive maintenance and remaining lifetime prognosis.
T2 - Sensor and Measurement Science International (SMSI) 2025
CY - Nuremberg, Germany
DA - 06.05.2025
KW - fiber optic sensors
KW - digital twin
KW - structural health monitoring
KW - hydrogen
KW - machine learning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633885
UR - https://www.ama-science.org/proceedings/details/5962
SN - 978-3-910600-06-5
DO - https://doi.org/10.5162/SMSI2025/C6.1
SP - 165
EP - 166
PB - AMA Service GmbH
CY - Wunstorf
AN - OPUS4-63388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martin, T
A1 - Zimmermann, E
A1 - Klitzsch, N
A1 - Hördt, A
A1 - Huisman, J A
A1 - Radic, T
A1 - Kruschwitz, Sabine
T1 - Round-robin test of SIP laboratory measurements using electrical test networks
N2 - This study presents the results of an interlaboratory test designed to evaluate the accuracy of spectral induced polarization (SIP) measurements using controlled electrical test networks. The study, conducted in Germany since 2006, involved 12 research institutes, six different impedance measurement devices and four types of electrical test networks specifically designed to evaluate phase shift errors in SIP measurements. The test networks, with impedances ranging from 100 to 150 kΩ, represent high-impedance samples with different phase characteristics, and pose the measurement challenges typical of such samples, including high contact impedances and parasitic capacitances. Four key findings emerged from the study: (1) Impedance measurements across all devices showed deviations within 1 per cent over a wide frequency range (0.001–1000 Hz); (2) phase errors remained below 1 mrad up to 100 Hz for most devices, but increased at higher frequencies due to parasitic capacitances and electromagnetic coupling effects; (3) lab-specific instruments have lower phase errors than field instruments when used in a laboratory environment, primarily due to the effects of long cables and too low input impedances of the field instruments; and (4) short cables and driven shielding technology effectively minimized parasitic capacitance and improved measurement accuracy. The study highlights the usefulness of test networks in assessing the accuracy of SIP measurements and raises awareness of the various factors influencing the quality of SIP data.
KW - Induced polarization
KW - Electrical properties
KW - Electrical resistivity tomography (ERT)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636755
DO - https://doi.org/10.1093/gji/ggaf153
SN - 0956-540X
VL - 242
IS - 1
SP - 1
EP - 13
PB - Oxford University Press (OUP)
AN - OPUS4-63675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schnell, Alexander
A1 - Rübner, Katrin
A1 - Seher, Julia
A1 - Müller, Constanze
A1 - Müller, Anette
A1 - Liebezeit, Steffen
A1 - Fenner, Jacob
A1 - Martin, Falk
A1 - Pniok, Nicole
T1 - Manufacturing and Application of Lightweight Aggregates from Construction and Demolition Waste
N2 - The objective of the REALight project is the development of a thermal process to produce lightweight aggregates in pilot scale and the implantation of a method to recover gypsum. Beside construction and demolition waste, various industrial by‐products are studied as raw materials. The raw materials have so far been unused or used in applications with lower quality requirements. To prove the performance of the lightweight aggregates, their technical properties are tested and their use in different applications is studied, e.g., for lightweight mortars as well as lightweight concretes.
KW - Construction and demolition waste
KW - Flue gas desulfurization gypsum
KW - Industrial by-products
KW - Infra-lightweight concrete
KW - Lightweight aggregates
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604643
DO - https://doi.org/10.1002/cite.202300211
SN - 0009-286X
VL - 96
IS - 7
SP - 969
EP - 975
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-60464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Boccaccini, A. R.
A1 - Müller, Ralf
T1 - Sintering and Crystallization of Fluoride-Containing Bioactive Glass F3
N2 - The fluoride-containing bioactive glass F3 with nominal composition (mol%) 44.8 SiO2 - 2.5 P2O3 - 36.5 CaO - 6.6 Na2O - 6.6 K2O - 3.0 CaF2 is a highly promising candidate for bone replacement applications. Its strong crystallization tendency, however, requires a thorough understanding of the interplay between glass powder particle size, surface crystallization, and sintering. Therefore, this study characterizes the sintering and crystallization of bulk specimens and various particle size fractions by differential thermal-analysis, laser scanning, electron microscopy, X-ray diffraction, and Infrared spectroscopy. Particle size fractions < 56 µm were found to fully densify, while crystals growing from the glass particle surface retard sintering of coarser fractions. Small amounts of a non-stoichiometrically calcium phosphosilicate (Ca14.92(PO4)2.35(SiO4)5.65) occurs as the primary crystal phase followed by combeite (Na4Ca4[Si6O18]) as a temporarily dominating phase. The surface crystallization of both phases was found to be mainly responsible for sinter retardation. During later stages of crystallization, additional phases such as cuspidine (Ca4F2Si2O7) and silicorhenanite (Na2Ca4(PO4)2SiO4) occur, but finally monoclinic wollastonite (CaSiO3) forms as the dominant phase.
KW - Bioactive Glass
KW - Sintering
KW - Crystallization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632482
DO - https://doi.org/10.52825/glass-europe.v3i.2564
SN - 2940-8830
VL - 3
SP - 105
EP - 124
AN - OPUS4-63248
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal friction and energy dissipation during fracture in silicate glasses
N2 - To obtain a deeper insight into the nature of energy dissipation during fracture, the internal friction of 13 borosilicate, aluminosilicate, soda-lime, and lead-containing glasses, for which inert crack growth data are known, was measured using dynamic mechanical thermal analysis. For asymmetrically bent glass beams, the loss tangent, tan δ, was determined between 0.2 and 50 Hz at temperatures between 273 K and the glass transition temperature, Tg. It was found that the area under the tan δ vs T·Tg−1 curve correlates with the crack growth exponent, n, in the empirical v = v0·KIn relation between crack growth velocity, v, and stress intensity, KI, which indicates that n correlates with the degree of energy dissipation of sub-Tg relaxation phenomena.
KW - Glass
KW - Internal friction
KW - Crack growth
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631582
DO - https://doi.org/10.1063/5.0255432
SN - 0021-9606
VL - 162
IS - 19
SP - 1
EP - 9
PB - AIP Publishing
AN - OPUS4-63158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pan, Z.
A1 - Waurischk, Tina
A1 - Duval, A.
A1 - Müller, Ralf
A1 - Deubener, J.
A1 - Krishnan, N. M. A.
A1 - Wondraczek, K.
A1 - Wondraczek, L.
T1 - Precise Real‐Time Measurement of Liquid Viscosity Using Digital Video Data
N2 - Quantitative knowledge of liquid viscosity is of fundamental importance in many areas of materials synthesis and processing. However, the determination of viscosity often relies on specialized experimental equipment, offline experimentation, or invasive procedures, in particular when required in extreme conditions such as at high temperature, high pressure, and in confined or corrosive environments. Here, this study proposes and validates a fast and simple method that mimics the intuitive perception of liquid flow within a quantitative framework. For this, this study employs digital video observation to derive quantitative values of the shear viscosity of liquids, with high precision and rapid acquisition rates. The technique involves capturing liquid dynamics after minor mechanical stimulation. Processed imaging data are indexed by similarity and referenced to a digital database generated with a finite element model, from which values of viscosity are obtained in line. The approach is tested on water at room temperature and on a high‐temperature glass melt. Covering a viscosity range of four orders of magnitude, both yield convincing agreement with tabulated reference data at low computational cost.
KW - Image analyses
KW - Liquids
KW - Materials discovery
KW - Similarity analyses
KW - Viscosities
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634606
DO - https://doi.org/10.1002/aisy.202500297
SN - 2640-4567
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-63460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Robens-Radermacher, Annika
A1 - Kujath, Cezary
A1 - Bos, Freek
A1 - Mechtcherine, Viktor
A1 - Unger, Jörg F.
T1 - Mechanical properties of 3D printed concrete: a RILEM TC 304-ADC interlaboratory study-Design and implementation of a database system for querying, sharing, and analyzing experimental data
N2 - Interlaboratory studies are essential for implementing standardized test methods for new innovative materials or technologies such as 3D concrete printing, certifying reference materials, and validating methods. They provide the basis for recommendations and design standards. Typically, the collected data are used only for one study and are published in paper form, without open access to the raw data files. However, preserving the collected data and analysis procedures in a shareable and reusable way leads to advantages for further usage. New data with the same structure can be added or the data can be analyzed by a new analysis procedure generating new knowledge. Additionally, resources are saved by avoiding the repetition of the same measurements. In line with the recent digitalization trend in material science and engineering, a database for the interlaboratory study on mechanical properties of 3D printed concrete conducted in RILEM Technical Committee 304-ADC is established. The challenges and experiences from defining the data structure, uploading the data, and using the database for evaluations are discussed. The openBIS software is used to create and fill the database, while an export method to an SQLite format is developed and discussed to generate a shareable and reusable database. With the exported database, querying the data is possible independently of a particular data management system. Additionally, examples of data processing with reusable workflows automating the analysis procedure are demonstrated.
KW - Data management
KW - Interlaboratory study
KW - 3D concrete printing
KW - Database
KW - Reusability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634627
DO - https://doi.org/10.1617/s11527-025-02650-9
SN - 1871-6873
VL - 58
IS - 184
SP - 1
EP - 37
PB - Springer Nature
AN - OPUS4-63462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gupta, Kanhaiya
A1 - Poka, Konstantin
A1 - Ulbricht, Alexander
A1 - Waske, Anja
T1 - Identification and authentication of additively manufactured components using their microstructural fingerprint
N2 - In the field of additive manufacturing, the ability to uniquely identify and authenticate parts is crucial for certification, logistics, and anti-counterfeiting efforts. This study introduces a novel methodology that leverages the intrinsic microstructural features of additively manufactured components for their identification, authentication, and traceability. Unlike traditional tagging methods, such as embedding QR codes on the surface or within the volume of parts, this approach requires no alteration to the printing process, as it utilizes naturally occurring microstructural characteristics. The proposed workflow involves the analysis of 3D micro-computed tomography data to identify specific voids that meet predefined identification criteria. This method is demonstrated on a batch of 24 parts manufactured with identical process parameters, proving capable of achieving unambiguous identification and authentication. By establishing a tamper-proof link between the physical part and its digital counterpart, this methodology effectively bridges the physical and digital realms. This not only enhances the traceability of additively manufactured parts but also provides a robust tool for integrating digital materials, parts databases, and product passports with their physical counterparts.
KW - Authentication
KW - Additive manufacturing
KW - X-ray Computed Tomography
KW - Digital fingerprint
KW - Unique identification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630356
DO - https://doi.org/10.1016/j.matdes.2025.113986
SN - 1873-4197
VL - 254
SP - 1
EP - 12
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-63035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deubener, J.
A1 - Allix, M.
A1 - Davis, M.J.
A1 - Duran, A.
A1 - Höche, T.
A1 - Honma, T.
A1 - Komatsu, T.
A1 - Krüger, S.
A1 - Mitra, I.
A1 - Müller, Ralf
A1 - Nakane, S.
A1 - Pascual, M.J.
A1 - Schmelzer, J.W.
A1 - Zanotto, E.D.
A1 - Zhou, S.
T1 - Updated definition of glass-ceramics
N2 - Glass-ceramics are noted for their unusual combination of properties and manifold commercialized products for consumer and specialized markets. Evolution of novel glass and ceramic processing routes, a plethora of new compositions, and unique exotic nano- and microstructures over the past 60 years led us to review the Definition of glass-ceramics. Well-established and emerging processing methods, such as co-firing, additive manufacturing, and laser patterning are analyzed concerning the core requirements of processing glass-ceramics and the Performance of the final products. In this communication, we propose a revised, updated definition of glass-ceramics, which reads “Glass-ceramics are inorganic, non-metallic materials prepared by controlled crystallization of glasses via different processing methods. They contain at least one type of functional crystalline phase and a residual glass. The volume fraction crystallized may vary from ppm to almost 100%”.
KW - Glass-ceramics definition
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464711
DO - https://doi.org/10.1016/j.jnoncrysol.2018.01.033
SN - 0022-3093
SN - 1873-4812
VL - 501
SP - 3
EP - 10
PB - Elsevier B.V.
AN - OPUS4-46471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Müller, Ralf
A1 - Reinsch, Stefan
A1 - Kiefer, P.
A1 - Deubener, J.
A1 - Balzer, R.
A1 - Behrens, H.
T1 - Crack Growth in Hydrous Soda-Lime Silicate Glass
N2 - Stable crack growth was measured for nominal dry and water-bearing (6 wt%) soda-lime silicate glasses in double cantilever beam geometry and combined with DMA studies on the effects of dissolved water on internal friction and glass transition, respectively. In vacuum, a decreased slope of logarithmic crack growth velocity versus stress intensity factor is evident for the hydrous glass in line with an increase of b-relaxation intensity indicating more energy Dissipation during fracture. Further, inert crack growth in hydrous glass is found to be divided into sections of different slope, which indicates different water related crack propagation mechanism. In ambient air, a largely extended region II is observed for the hydrous glass, which indicates that crack growth is more sensitive to ambient water.
KW - Internal friction
KW - Soda-lime silicate glass
KW - Water content
KW - Stable crack growth
KW - DCB geometry
KW - Stress intensity factor
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506829
DO - https://doi.org/10.3389/fmats.2020.00066
VL - 7
SP - Articel 66
AN - OPUS4-50682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Müller, Thoralf
A1 - Mietz, Jürgen
A1 - Burkert, Andreas
T1 - Investigation of the influence of iron‐containing abrasives on the corrosion behaviour of the aluminium alloy AlSi1.2Mg0.4
N2 - The corrosion resistance of aluminium surfaces is closely linked to the surfacecstate after a grinding process. For years, iron‐containing abrasive materials were suspected to lead to increased corrosion susceptibility after processing of aluminium surfaces. To prove a possible correlation between the iron content of an abrasive and the corrosion behaviour of aluminium components, scientific investigations and experimentally practical corrosion tests are necessary.
For the current investigation, specimens of a technical Al‐Si alloy from the same batch were used. The test specimens were mechanically ground with various resin‐bonded model abrasives containing different iron contents. The performed corrosion tests did not reveal a negative influence of the different iron‐containing abrasives on the corrosion behaviour of the Al–Si alloy.
However, the most sensitive measuring method (electrochemical noise)
showed differences in the surface activity depending on the type of abrasive.
KW - Aluminium
KW - Corrosion
KW - Corrosion testing
KW - Grinding
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506762
DO - https://doi.org/10.1002/maco.202011657
SN - 0947-5117
SN - 1521-4176
VL - 71
IS - 10
SP - 1667
EP - 1679
PB - Wiley‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kiefer, P.
A1 - Maiwald, M.
A1 - Deubener, J.
A1 - Balzer, R.
A1 - Behrens, H.
A1 - Waurischk, Tina
A1 - Reinsch, Stefan
A1 - Müller, Ralf
T1 - Automated Analysis of Slow Crack Growth in Hydrous Soda-Lime Silicate Glasses
N2 - To explore the impact of ambient and structural water on static fatigue, the initiation and growth of 3279 Vickers induced median radial cracks were automatically recorded and analyzed. We find that humidity is more efficient in initiating cracks and promoting their growth than water, which is dissolved in the glass structure. In particular for slow crack growth (< 3x10-6 m s-1), tests in dry nitrogen showed a considerable decrease in the crack growth exponent with increasing water content of the glasses. On the other hand, if tests were performed in humid air, the crack growth exponent was independent of the water content of the hydrous glasses, while stress intensity decreased slightly. These observations indicate that water promotes the processes at the crack-tip regardless of its origin. However, ambient water is more efficient.
KW - Indentation fracture toughness
KW - Slow crack growth
KW - Automated analysis
KW - Hydrous glass
KW - Vickers indentation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513085
DO - https://doi.org/10.3389/fmats.2020.00268
VL - 7
SP - 268
AN - OPUS4-51308
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Welter, T.
A1 - Müller, Ralf
A1 - Deubener, J.
A1 - Marzok, Ulrich
A1 - Reinsch, Stefan
T1 - Hydrogen Permeation Through Glass
N2 - Physical storage of gaseous hydrogen under high-pressure in glassy micro-containers such as spheres and capillaries is a promising concept for enhancing safety and the volumetric capacity of mobile hydrogen storage systems. As very low permeation through the container wall is required for storage of compressed hydrogen, development of glasses of minimal hydrogen permeability is needed. For this purpose, one has to understand better the dependence of hydrogen permeability on glass structure. The paper points out that minimizing the accessible free volume is as one strategy to minimize hydrogen permeability. Based on previously measured and comprehensive literature data, it is shown that permeation is independently controlled by ionic porosity and network modifier content. Thus, ionic porosity in modified and fully polymerized networks can be decreased equally to the lowest hydrogen permeability among the glasses under study. Applying this concept, a drop of up to 30,000 with respect to the permeation of hydrogen molecules through silica glass is attainable.
KW - Ionic porosity
KW - hydrogen storage
KW - Glass
KW - Permeability
KW - Solubility
KW - Diffusivity
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513927
DO - https://doi.org/10.3389/fmats.2019.00342
VL - 6
SP - Article 342
AN - OPUS4-51392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heuser, Lina
A1 - Nofz, Marianne
A1 - Müller, Ralf
T1 - Alkali and alkaline earth zinc and lead borate glasses: Sintering and crystallization
N2 - Glasses in the systems Me2O-ZnO-B2O3 with Me = Li, Na, K, Rb (MeZB), Na2O-ZnO-CuO-B2O3 (NZCuB), CaO-ZnO-B2O3 (CaZB), and Li2O-PbO-B2O3 (LPbB) as a reference, were studied by differential thermal analysis, dilatometry, rotational viscometry, and heating microscopy. A decrease of viscosity and sintering range was found with decreasing number of fourfold coordinated boron. The viscosity of the alkali zinc borate glasses varies only slightly. LPbB and CaZB stand out by their reduced and increased viscosities, respectively. Sodium, potassium, and calcium zinc borate glasses possess a fragility above 76. All glasses were sintered to full density before crystallization. Mostly binary zinc borate phases govern crystallization. A ternary crystalline phase was detected only in the potassium containing sample. The Weinberg glass stability parameter ranges between 0.07 and 0.12. This is caused by the presence of several crystalline phases and varying melting points of even the same crystalline phase in different glass matrices.
KW - Alkali zinc borate glasses
KW - Lead borate glasses
KW - Viscosity
KW - Sintering
KW - Crystallization
KW - Fragility
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556128
DO - https://doi.org/10.1016/j.nocx.2022.100116
SN - 2590-1591
VL - 15
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Sintering and foaming of bioactive glasses
N2 - Sintering, crystallization, and foaming of 44.8SiO2–2.5P2O3–36.5CaO–6.6Na2O–6.6K2O–3.0CaF2 (F3) and 54.6SiO2–1.7P2O3–22.1CaO–6.0Na2O–7.9K2O–7.7MgO (13–93) bioactive glass powders milled in isopropanol and CO2 were studied via heating microscopy, differential thermal analysis, vacuum hot extraction (VHE), Infrared spectroscopy, and time-of-flight secondary ion mass spectrometry. Full densification was reached in any case and followed by significant foaming.
VHE studies show that foaming is driven by carbon gases and carbonates were detected by Infrared spectroscopy to provide the major foaming source. Carbonates could be detected even after heating to 750◦C, which hints on a thermally very stable species or mechanical trapping. Otherwise, dark gray compact colors for milling in isopropanol indicate the presence of residual carbon as well. Its significant contribution to foaming, however, could not be proved and might be
limited by the diffusivity of oxygen needed for carbon oxidation to carbon gas.
KW - Bioactive Glass
KW - Crystallization
KW - Foaming
KW - Sintering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552454
DO - https://doi.org/10.1111/jace.18626
SN - 0002-7820
SP - 1
EP - 11
PB - Wiley online library
AN - OPUS4-55245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Chruscicki, Sebastian
A1 - Schukar, Marcus
A1 - Münzenberger, Sven
A1 - Krebber, Katerina
T1 - Application of Intensity-Based Coherent Optical Time Domain Reflectometry to Bridge Monitoring
N2 - Although distributed fiber sensing techniques have been widely used in structural health monitoring, the measurement results of bridge monitoring, particularly under destructive testing, have rarely been reported. To the best of our knowledge, this paper is the first report of distributed vibration measurement results, which we obtained during a three-day destructive test on an abolished bridge. A coherent optical time domain reflectometry (COTDR) was used to acquire the vibration information while the bridge was being sawed. The obtained signal was analyzed in time and frequency domain. Some characteristics of the sawing-induced vibration were retrieved by the short-time Fourier transform; the vibration exhibited several high frequency components within the measured range up to 20 kHz and all the components appeared in the same time slot. Some unexpected signals were also detected. Thorough analysis showed that they are quite different from the sawing-induced vibration and are believed to originate from internal damage to the bridge (probably the occurrence of cracks).
KW - Destructive testing
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed acoustic sensing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547451
DO - https://doi.org/10.3390/s22093434
VL - 22
IS - 9
SP - 3434
PB - MDPI
AN - OPUS4-54745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deubener, J.
A1 - Behrens, H.
A1 - Müller, Ralf
T1 - An overview on the effect of dissolved water on the viscosity of soda lime silicate melts
N2 - In this review article, the impact of dissolved water on the viscous properties of soda lime silicate melts is addressed against the background of the upcoming switch from natural gas to hydrogen combustion. This change will lead to an increase in the total water content of the glasses by up to 0.4 mol%. In order to better define possible influences of water speciation, water-rich glasses were synthesised under increasing pressure up to the kbar range. It is shown that a distinction must be made between the influence of dissolved OH-groups and H2Omolecules in order to accurately reflect the dependence of isokom temperatures on water content. In addition, an increase of one order of magnitude in the tolerance to higher deformation rates was observed for the range of expected increased water contents during isothermal deformation processes, which is based on the timetemperature superposition principle, i.e. congruent flow curves were determined under isokomal conditions.
KW - Water in glass
KW - Viscosity
KW - Soda lime silicate glass
KW - Shear thinning
KW - Nydrogen melting
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587276
DO - https://doi.org/10.1016/j.nocx.2023.100195
VL - 19
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-58727
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gomes Fernandes, Roger
A1 - Al-Mukadam, Raschid
A1 - Bornhöft, Hansjörg
A1 - Reinsch, Stefan
A1 - Müller, Ralf
A1 - Selle, Susanne
A1 - Deubener, Joachim
T1 - Viscous Sintering of Acid Leached Glass Powders
N2 - The process of viscous flow sintering is a phenomenon that is closely linked to the surface properties of the glass particles. In this work, we studied the extreme case of acid-leaching of soda-lime-silicate glass beads of two different particle size distributions and its effects on non-isothermal viscous sintering of powder compacts. Depth profiling of the chemical composition after leaching revealed a near-surface layer depleted in alkali and alkaline earth ions, associated with concurrent hydration as mass loss was detected by thermogravimetry. Heating microscopy showed that acid treatment of glasses shifted the sinter curves to higher temperatures with increasing leaching time. Modelling of the shrinkage with the cluster model predicted a higher viscosity of the altered surface layer, while analysis of the time scales of mass transport of mobile species (Na+, Ca2+ and H2O) during isochronous sintering revealed that diffusion of Na+ can compensate for concentration gradients before sintering begins. Also, exchanged water species can diffuse out of the altered layer, but the depletion of Ca2+ in the altered surface layer persists during the sinter interval, resulting in a glass with higher viscosity, which causes sintering to slow down.
KW - Glass powder
KW - Viscous sintering
KW - Acid-leaching
KW - Sinter retardation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589008
DO - https://doi.org/10.52825/glass-europe.v1i.681
VL - 1
SP - 37
EP - 53
AN - OPUS4-58900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Viscous healing of Vickers indentation–induced cracks in glass
N2 - AbstractViscous healing of cracks induced by the Vickers indentation in a soda lime magnesium silicate, a soda borosilicate, and a soda aluminosilicate glass (NAS) was studied by laser scanning microscopy. Plots of the crack length, width, and depth normalized to the initial crack length versus time over viscosity merge into single master curves of each of these quantities for each glass. Despite glass properties do not differ strikingly from each other, however, these master curves strongly differ among the glasses. This finding was attributed to a different interplay of various crack healing phenomena. Lateral cracks were found to be responsible for the bulging of the sample surface around the Vickers imprint, which in turn promotes radial crack widening as the main cause of healing delay. The most rapid healing of lateral cracks was observed in NAS in which bulging and crack widening were least pronounced.
KW - Crack healing
KW - Glass
KW - Vickers indentation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587295
DO - https://doi.org/10.1111/jace.19245
SN - 0002-7820
VL - 106
IS - 10
SP - 5795
EP - 5805
PB - Wiley
AN - OPUS4-58729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reinsch, Stefan
A1 - Welter, T.
A1 - Müller, Ralf
A1 - Deubener, J.
T1 - Hydrogen Permeability of Tectosilicate Glasses for Tank Barrier Liners
N2 - The permeation of hydrogen gas was studied in meta-aluminous (tectosilicate) glass powders of Li2O×Al2O3×SiO2 (LAS), Na2O×Al2O3×SiO2 (NAS) and MgO×Al2O3×SiO2 (MAS) systems by pressure loading and vacuum extraction in the temperatures range 210–310 °C. With this method, both the solubility S and the diffusivity D were determined, while the permeability was given by the product SD. For all glasses, S was found to decrease with temperature, while D increased. Since the activation energy of diffusion of H2 molecules exceeded that of dissolution, permeation increased slightly with temperature. When extrapolated to standard conditions (25 °C), the permeability of tectosilicate glasses was found to be only 10-22–10-24 mol H2 (m s Pa)-1, which is 8–10 magnitudes lower than most polymers. Thin glass liners of these compositions are expected to be the most effective barrier for tanks of pressurised hydrogen.
KW - Hydrogen permeation
KW - Aluminosilicate glasses
KW - Hydrogen storage tank
KW - Glass liner
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587284
DO - https://doi.org/10.52825/glass-europe.v1i.425
VL - 1
SP - 1
EP - 11
AN - OPUS4-58728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheffler, Franziska
A1 - Fleck, Mirjam
A1 - Busch, Richard
A1 - Casado, Santiago
A1 - Gnecco, Enrico
A1 - Tielemann, Christopher
A1 - Brauer, Delia S.
A1 - Müller, Ralf
T1 - Surface Crystallization of Barium Fresnoite Glass: Annealing Atmosphere, Crystal Morphology and Orientation
N2 - Controlled oriented crystallization of glass surfaces is desired for high precision applications, since the uppermost crystal layer significantly influences the properties of the material. In contrast to previous studies, the data presented here deal with separated crystals growing at defect-free surfaces in four atmospheres with different degrees of humidity (ambient/dry air, argon and vacuum). A glass with the composition 2 BaO–TiO2–2.75 SiO2 was heat-treated at 825 °C until fresnoite (Ba2TiSi2O8) grew to a significant size. The crystal growth rate is found to increase with increasing humidity. The morphology of the crystals changes from highly distorted dendrites in the driest atmosphere (vacuum) to circular/spear-head-shaped crystals in the wettest atmosphere (ambient air), which we attribute to a decrease in viscosity of the glass surface due to water uptake. The least distorted crystals appear in the form of depressions of up to 6 µm. This has an influence on the observed crystal orientation, as measured by electron backscatter diffraction (EBSD). The pulled-in crystals change the orientation during growth relative to the flat glass surface due to an enrichment in SiO2 at the crystal fronts. This confirms that the orientation of crystals is not fixed following nucleation.
KW - Fresnoite
KW - Surface crystallization
KW - Crystal growth
KW - Crystal morphology
KW - Crystal orientation
KW - EBSD
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587230
DO - https://doi.org/10.3390/cryst13030475
VL - 13
IS - 3
SP - 1
EP - 17
PB - MDPI AG
CY - Basel
AN - OPUS4-58723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seher, Julia
A1 - Rübner, Katrin
A1 - Müller, Constanze
A1 - Pniok, N.
A1 - Dreisow, B.
T1 - Leichte Gesteinskörnungen hergestellt aus Bau- und Abbruchabfällen – Applikation in der Denkmalpflege
N2 - Im Rahmen des BMBF-geförderten Forschungsprojekts ReMin – REALight werden in einem Projektteam aus Industriepartnern und Forschungseinrichtungen unter Koordination der Bauhaus-Universität Weimar leichte Gesteinskörnungen aus Bau- und Abbruchabfällen und industriellen Nebenprodukten auf thermischem Weg hergestellt. Die Aufgabe der Bundesanstalt für Materialforschung und -prüfung (BAM) ist es, diese im Drehrohrofen erzeugten Blähgranulate für gebundene Anwendungen in Beton und Mörtel umfassend zu charakterisieren. Gemeinsam mit der Opus Denkmalpflege GmbH wird die Applikation feiner, gebrochener Blähgranulate in leichten Steinergänzungsmörteln für die Restaurierung von Sandsteinobjekten untersucht. Hierzu wird ein zweischichtiges Mörtelsystem bestehend aus einem Füll- und einem Deckmörtel entwickelt. Erste Ergebnisse der Rezepturentwicklung verschiedener kalkhaltiger Leichtmörtel mit gebrochenen Blähgranulaten werden vorgestellt. Die neuen Leichtmörtel sind hinsichtlich der entwickelten Druckfestigkeit gleichwertig gegenüber herkömmlichen Restauriermörteln.
T2 - 21. Internationale Baustofftagung (ibausil)
CY - Weimar, Germany
DA - 13.09.2023
KW - Baustoffrecycling
KW - Mauerwerkbruch
KW - Leichte Gesteinskörnungen
KW - Denkmalpflege
KW - Restauriermörtel
KW - Steinergänzungsmassen
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590685
DO - https://doi.org/10.1002/cepa.2839
SN - 2509-7075
VL - 6
SP - 861
EP - 866
PB - Ernst & Sohn GmbH
AN - OPUS4-59068
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Ralf
A1 - Behrens, Harald
A1 - Ageo-Blanco, Boris
A1 - Reinsch, Stefan
A1 - Wirth, Thomas
T1 - Foaming Species and Trapping Mechanisms in Barium Silicate Glass Sealants
N2 - Barium silicate glass powders 4 h milled in CO2 and Ar and sintered in air are studied with microscopy, total carbon analysis, differential thermal Analysis (DTA), vacuum hot extraction mass spectroscopy (VHE-MS), Fourier-transformed infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), and time-of-flight secondary-ion mass spectrometry (TOF-SIMS). Intensive foaming of powder compacts is evident, and VHE studies prove that foaming is predominantly caused by carbonaceous species for both milling gases. DTA Shows that the decomposition of BaCO3 particles mix-milled with glass powders occurs at similar temperatures as foaming of compacts. However, no carbonate at the glass surface could be detected by FTIR spectroscopy, XPS, and TOF-SIMS after heating to the temperature of sintering. Instead, CO2 molecules unable to rotate identified by FTIR spectroscopy after milling, probably trapped by mechanical dissolution into the glass bulk. Such a mechanism or microencapsulation in cracks and particle aggregates can explain the contribution of Ar to foaming after intense milling in Ar atmosphere. The amount of CO2 molecules and Ar, however, cannot fully explain the extent of foaming. Carbonates mechanically dissolved beneath the surface or encapsulated in cracks and micropores of particle aggregates are therefore probably the major foaming source.
KW - Milling
KW - Foaming
KW - Glass powder
KW - Sintering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531227
DO - https://doi.org/10.1002/adem.202100445
SN - 1438-1656
VL - 24
IS - 6
SP - 2100445-1
EP - 2100445-13
AN - OPUS4-53122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heuser, Lina
A1 - Nofz, Marianne
A1 - Müller, Ralf
A1 - Deubener, J.
T1 - Silver dissolution and precipitation in an Na2O–ZnO–B2O3 metallization paste glass
N2 - Thermally stimulated interactions between silver and glass, that is, silver dissolution as Ag+ and precipitation as Ag0 were studied in two glass series of molar target composition xAg2O–(19 − x)Na2O–28ZnO–53B2O3 with x = 0, 0.1, 0.5, 5 and (19Na2O–28ZnO–53B2O3)+yAg2O with y = 0.01, 0.05. These act as model for low-melting borate glasses being part of metallization pastes. The occurrence of metallic silver precipitates in melt-quenched glass ingots demonstrated that silver dissolved only in traces (< 0.01 mol%) in the glasses. The dissolved silver was detected by means of Raman spectroscopy and energy-dispersive X-ray spectroscopy. Increasing x in the batch could not lead to a significant increase of the silver ion fraction in the glass as possible in binary silver borate glasses. In situ observation of heated AgNO3 mixed with the base glass frit in a hot stage microscope showed that Ag0 precipitation occurs already at the solid state. At higher temperatures, small droplets of liquid silver were found to move freely within the melt, whereas coalescence caused a stepwise increase of their size.
These results contribute to the understanding of formation of silver precipitates in metallization pastes described in the literature.
KW - Silver metallization paste
KW - Batch reactions
KW - Borate
KW - Glass forming melts
KW - Glass manufacturing
KW - Raman spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559433
DO - https://doi.org/10.1111/ijag.16613
SN - 2041-1286
SP - 1
EP - 11
PB - Wiley Online Library
AN - OPUS4-55943
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karapanagiotis, Christos
A1 - Heimann, Jan
A1 - Duffner, Eric
A1 - Charmi, Amir
A1 - Schukar, Marcus
A1 - Hashemi, Seyedreza
A1 - Prager, Jens
T1 - Towards predictive maintenance of hydrogen pressure vessels based on multi-sensor data fusion and digital twin modeling
N2 - Hydrogen pressure vessels are among the most essential components for reliable hydrogen technology. Under current regulations, a mostly conservative strategy is employed, restricting the usage time of hydrogen pressure vessels without providing information on the real remaining lifetime. During the service life, pressure vessels are inspected periodically. However, no established method that can provide continuous monitoring or information on the remaining safe service life of the vessel. In this paper, we propose a sensor network for Structural Health Monitoring (SHM) of hydrogen pressure vessels where data from all sensors are collected and centrally evaluated. Specifically, we integrate three different SHM sensing technologies namely Guided Wave ultrasonics (GW), Acoustic Emission testing (AT), and distributed Fiber Optic Sensing (FOS). This integrated approach offers significantly more information and could therefore enable a transition from costly and time-consuming periodic inspections to more efficient and modern predictive maintenance strategies, including Artificial Intelligence (AI)-based evaluation. This does not only have a positive effect on the operational costs but enhances safety through early identification of critical conditions in the overall system in real-time. We demonstrate an experimental set-up of a lifetime test where a Type IV Composite Overwrapped Pressure Vessel (COPV) is investigated under cyclic loading instrumented with AT, FOS, and GW methods. We acquired data from the sensor network until the pressure vessel failed due to material degradation. The data collected using the three different SHM sensor technologies is planned to be evaluated individually, using data fusion, and AI. In the future, we aim to integrate the measurement setup into a hydrogen refueling station with the data stream implemented into a digital signal processing chain and a digital twin.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Acoustic emission
KW - Ultrasonic guided waves
KW - Fiber optic sensors
KW - Hydrogen
KW - Pressure vessels
KW - Structural health monitoring
KW - Machine learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602764
UR - https://www.ndt.net/search/docs.php3?id=29702
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-60276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Karapanagiotis, Christos
A1 - Schukar, Marcus
A1 - Breithaupt, Mathias
A1 - Duffner, Eric
A1 - Ulbricht, Alexander
A1 - Prager, Jens
A1 - Krebber, Katerina
T1 - Structural health monitoring of hydrogen pressure vessels using distributed fiber optic sensing
N2 - We report on distributed fiber optic sensing-based monitoring of hydrogen composite overwrapped pressure vessels (COPV) to simultaneously increase the operational lifespan and mitigate maintenance costs. Our approach represents, to the best of our knowledge, the first application of distributed fiber optic sensing for COPV Type IV monitoring, where the sensing fibers are attached to the surface, rather than integrated into the composite material. Specifically, we attach an optical fiber of 50 m to the pressure vessel's surface, covering both the cylindrical and dome sections. We note that our fiber optic sensing technique relies on swept wavelength interferometry providing strain information along the entire length of the optical fiber with high spatial resolution even at the millimeter scale. When the vessel is pressurized, the sensing optical fiber shows a linear strain response to pressure at every position along the fiber. After thousands of load cycles, the vessel finally fails with the optical fiber detecting and precisely localizing the damage in the vessel’s blind dome area. Furthermore, we discuss the potential of state-of-the-art signal processing methods and machine learning for advancing predictive maintenance. This could reduce the number of regular inspections, mitigate premature maintenance costs, and simultaneously increase the vessel’s remaining safe service life. We believe that the structural health monitoring of hydrogen pressure vessels with fiber optic sensors can enhance trust in hydrogen technology contributing to the energy transition in the future.
T2 - 11th European Workshop on Structural Health Monitoring
CY - Potsdam, Germany
DA - 10.06.2024
KW - Hydrogen
KW - Fiber optic sensors
KW - Composites
KW - Machine learning
KW - Structural health monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602731
UR - https://www.ndt.net/search/docs.php3?id=29701
SP - 1
EP - 7
PB - NDT.net
AN - OPUS4-60273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Ya‐Fan
A1 - Arendt, Felix
A1 - Bornhöft, Hansjörg
A1 - de Camargo, Andréa S. S.
A1 - Deubener, Joachim
A1 - Diegeler, Andreas
A1 - Gogula, Shravya
A1 - Contreras Jaimes, Altair T.
A1 - Kempf, Sebastian
A1 - Kilo, Martin
A1 - Limbach, René
A1 - Müller, Ralf
A1 - Niebergall, Rick
A1 - Pan, Zhiwen
A1 - Puppe, Frank
A1 - Reinsch, Stefan
A1 - Schottner, Gerhard
A1 - Stier, Simon
A1 - Waurischk, Tina
A1 - Wondraczek, Lothar
A1 - Sierka, Marek
T1 - Ontology‐Based Digital Infrastructure for Data‐Driven Glass Development
N2 - The development of new glasses is often hampered by inefficient trial‐and‐error approaches. The traditional glass manufacturing process is not only time‐consuming, but also difficult to reproduce with inevitable variations in process parameters. These challenges are addressed by implementing an ontology‐based digital infrastructure coupled with a robotic melting system. This system facilitates high‐throughput glass synthesis and ensures the collection of consistent process data. In addition, the digital infrastructure includes machine learning models for predicting glass properties and a tool for extracting patent information. Current glass databases have significant gaps in the relationships between compositions, process parameters, and properties due to inconsistent studies and nonconforming units. In addition, process parameters are often omitted, and even original literature references provide limited information. By continuously expanding the database with consistent, high‐quality data, it is aimed to fill these gaps and accelerate the glass development process.
KW - Digitalisation
KW - Data-driven glass development
KW - Ontology
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625844
DO - https://doi.org/10.1002/adem.202401560
SN - 1527-2648
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-62584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
T1 - Fast crack healing in glass-matrix composites with rigid filler percolation frameworks
N2 - To ensure the durability of solid oxide fuel cell sealants, the understanding of the microstructural influence on viscous crack healing is essential. To this end, the effect of microstructure with respect to the spatial distribution of filler particles on viscous crack healing was studied with confocal laser scanning microscopy in glass-matrix composites (GMCs) made by mix-milling and sintering of sodalime magnesium silicate glass and Φ ≈ 6 vol% ZrO2 chemically inert rigid filler particles. This way, no change in Φ occurred during the crack healing treatments studied on Vickers indentation-induced radial cracks in polished GMC surfaces.
Different microstructures were mimicked using different ZrO2 particle sizes for mix-milling. Unlike coarse ZrO2 particles, similar in size to the glass particle, fine ZrO2 particles, much smaller than the glass particles, form a rigid percolation framework (RPF) of ZrO2 filler particles around the former glass particles or glass particle agglomerates. For this RPF microstructure, crack healing was observed more readily as crack healing retardation phenomena like large-scale crack widening and crack tip rounding were strongly reduced, whereas narrow cracks could still heal locally within the glassy regions.
KW - Crack healing
KW - Glass matrix composite
KW - Rigid percolation frameworks
KW - Vickers indentation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625921
DO - https://doi.org/10.1111/jace.20386
SN - 0002-7820
SP - 1
EP - 10
PB - Wiley
AN - OPUS4-62592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karapanagiotis, Christos
A1 - Breithaupt, Mathias
A1 - Duffner, Eric
A1 - Schukar, Marcus
T1 - Real-time monitoring of hydrogen composite pressure vessels using surface-applied distributed fiber optic sensors
N2 - In this paper, we report to the best of our knowledge for the first time on continuous real-time monitoring of composite overwrapped pressure vessels (COPVs) designed for hydrogen storage using surface-applied distributed fiber optic sensors (DFOS). We conducted continuous and real-time DFOS measurements during pressure cycling tests consisting of periodic pressure fluctuations between 20 bar and 875 bar, with a rate of 5 cycles min−1. During pressure cycling, the DFOS system measured strain changes, that under normal operating conditions were linearly correlated to changes in pressure. To detect and quantify damage-related anomalies, we trained a simple regression model to predict strain from pressure data and used the difference between predicted and measured values as a damage indicator. With our approach, the DFOS system not only detected and localized the damage but also continuously tracked its evolution in real time under dynamic pressure conditions. Furthermore, unlike previous studies where optical fibers were embedded within the composite structure, we applied them on the COPV surface, reducing both implementation cost and time while eliminating the need to modify the COPV manufacturing process. Based on our results, we are confident that DFOS can enhance safety and facilitate the transition from time-consuming periodic inspections to more efficient, machine learning-based predictive maintenance.
KW - Fiber optic sensors
KW - Hydrogen
KW - Structural health monitoring
KW - Pressure vessels
KW - Predictive maintenance
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627644
DO - https://doi.org/10.1088/2515-7647/adb9ac
SN - 2515-7647
VL - 7
IS - 2
SP - 2
EP - 10
PB - IOP Publishing Ltd
CY - Bristol, UK
AN - OPUS4-62764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Balzer, R.
A1 - Behrens, H.
A1 - Waurischk, Tina
A1 - Reinsch, Stefan
A1 - Müller, Ralf
A1 - Kiefer, P.
A1 - Deubener, J.
A1 - Fechtelkord, M.
T1 - Water in Alkali Aluminosilicate Glasses
N2 - To understand the influence of water and alkalis on aluminosilicate glasses, three polymerized glasses with varying ratios of Na/K were synthesized [(22. 5-x)Na2O-xK2O-22.5 Al2O3-55 SiO2 with x = 0, 7.5, and 11.25]. Subsequently, these glasses were hydrated (up to 8 wt% H2O) in an internally heated gas pressure vessel. The density of hydrous glasses linearly decreased with water content above 1 wt%, consistent with the partial molar volume of H2O of 12 cm3/mol. Near-infrared spectroscopy revealed that hydroxyl groups are the dominant species at water content of <4 wt%, and molecular water becomes dominating at water content of >5 wt%. The fraction of OH is particularly high in the pure Na-bearing glass compared to the mixed alkali glasses. 27Al magic angle spinning-NMR spectroscopy shows that aluminum is exclusively fourfold coordinated with some variations in the local geometry. It appears that the local structure around Al becomes more ordered with increasing K/Na ratio. The incorporation of H2O reinforces this effect. The differential thermal analysis of hydrous glasses shows a significant mass loss in the range of glass transition already during the first upscan, implying the high mobility of water in the glasses. This observation can be explained by the open structure of the aluminosilicate network and by the low dissociation enthalpy of H2O in the glasses (≈ 8 kJ/mol). The effect of the dissolved H2O on the glass transition temperature is less pronounced than for other aluminosilicate glasses, probably because of the large fraction of Al in the glasses.
KW - NMR spectroscopy
KW - Alkali aluminosilicate glasses
KW - Water speciation
KW - Glass transition
KW - Infrared spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509497
DO - https://doi.org/10.3389/fmats.2020.00085
VL - 7
SP - 85
AN - OPUS4-50949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittrich, Tim
A1 - Weise, Frank
A1 - Stelzner, Ludwig
T1 - The impact of blended cements on the spalling behavior of concrete at elevated temperatures: a review
N2 - The cement and concrete industries are striving to reduce the CO2 emissions caused by the production of Portland cement. An effective way to achieve this is to replace Portland cement clinker with more environmentally friendly supplementary cementitious materials (SCMs) to produce blended cements. A variety of different SCMs are used today, from fly ash to more exotic options such as rice husk ash or waste glass powder. Depending on its material properties, concrete exposed to fire may experience spalling caused by thermomechanical and thermohydraulic mechanisms. Severe spalling leads to a reduction in the cross-section and exposure of the reinforcement, jeopardizing the load-bearing capacity of the concrete element. The use of blended cements changes the concrete properties which can affect spalling behavior at high temperatures. The link between high temperature and spalling behavior of concrete with blended cements has been investigated in several studies. A review of the existing literature led to the conclusion that the cement type influences the spalling behavior of concrete. However, the relationship does not appear to be clear, as there are contradictions and inconsistencies between the evaluated results. Therefore, further in-depth studies will help to gain a more precise understanding of the effects of blended cements on the spalling behavior of concrete at elevated temperatures.
KW - Fire-induced concrete spalling
KW - Concrete
KW - Blended cements
KW - SCM
KW - Filler
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635182
DO - https://doi.org/10.1617/s11527-025-02713-x
SN - 1359-5997
VL - 58
IS - 5
SP - 1
EP - 21
PB - Springer Science and Business Media LLC
AN - OPUS4-63518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolfs, Rob
A1 - Versteegen, Jelle
A1 - Santhanam, Manu
A1 - Bhattacherjee, Shantanu
A1 - Bos, Freek
A1 - Robens-Radermacher, Annika
A1 - Muthukrishnan, Shravan
A1 - Menna, Costantino
A1 - Ozturk, Onur
A1 - Ozyurt, Nilufer
A1 - Roupec, Josef
A1 - Richter, Christiane
A1 - Jungwirth, Jörg
A1 - Miranda, Luiza
A1 - Ammann, Rebecca
A1 - Caron, Jean-François
A1 - de Bono, Victor
A1 - Monte, Renate
A1 - Navarrete, Iván
A1 - Eugenin, Claudia
A1 - Lombois‑Burger, Hélène
A1 - Baz, Bilal
A1 - Sinka, Maris
A1 - Sapata, Alise
A1 - Harbouz, Ilhame
A1 - Zhang, Yamei
A1 - Jia, Zijian
A1 - Kruger, Jacques
A1 - Mostert, Jean‑Pierre
A1 - Šter, Katarina
A1 - Šajna, Aljoša
A1 - Kaci, Abdelhak
A1 - Rahal, Said
A1 - Snguanyat, Chalermwut
A1 - Arunothayan, Arun
A1 - Zhao, Zengfeng
A1 - Mai, Inka
A1 - Rasehorn, Inken Jette
A1 - Böhler, David
A1 - Freund, Niklas
A1 - Lowke, Dirk
A1 - Neef, Tobias
A1 - Taubert, Markus
A1 - Auer, Daniel
A1 - Hechtl, C. Maximilian
A1 - Dahlenburg, Maximilian
A1 - Esposito, Laura
A1 - Buswell, Richard
A1 - Kolawole, John
A1 - Isa, Muhammad Nura
A1 - Liu, Xingzi
A1 - Wang, Zhendi
A1 - Subramaniam, Kolluru
A1 - Mechtcherine, Viktor
T1 - Mechanical properties of 3D printed concrete: a RILEM TC 304-ADC interlaboratory study — flexural and tensile strength
N2 - This paper discusses the flexural and tensile strength properties of 3D printed concrete, based on the results of a RILEM TC 304-ADC interlaboratory study on mechanical properties. These properties are determined using different testing techniques, including 3- and 4-point flexural tests, splitting tests, and uniaxial tension tests, on specimens extracted from large 3D printed elements in accordance with a prescribed study plan. The relationship between compressive and flexural or tensile strengths, cast or printed samples, different types of tests, and different loading orientations, are analysed to understand the influence of 3D printing. As expected, the strength can reduce significantly when the main tensile stress is acting perpendicular to the interface between layers. The role of deviations from the standard study procedure, in terms of the time interval between the placing of subsequent layers, or the adoption of a different curing strategy, are also assessed. While the increased time interval significantly impacts the strength in the critical direction, the use of variable curing conditions does not seem to have a clear-cut effect on the strength ratios of the printed to cast specimens. Additionally, the paper looks at the variability in the results for the printed specimens, in order to emphasize the need for multiple replicates for obtaining a proper result. An extensive insight into the aspects affecting the variability is presented in the paper. Finally, with the limited dataset available for specimens tested at a larger scale, it is difficult to arrive at a clear understanding of the role of specimen size (i.e., greater number of layers).
KW - 3D concrete printing
KW - Digital fabrication
KW - Flexural strength
KW - Tensile strength
KW - Interlayer bond strength
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634655
DO - https://doi.org/10.1617/s11527-025-02687-w
SN - 1871-6873
VL - 58
IS - 5
SP - 1
EP - 33
PB - Springer Nature
AN - OPUS4-63465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mechtcherine, Viktor
A1 - Muthukrishnan, Shravan
A1 - Robens-Radermacher, Annika
A1 - Wolfs, Rob
A1 - Versteege, Jelle
A1 - Menna, Costantino
A1 - Ozturk, Onur
A1 - Ozyurt, Nilufer
A1 - Roupec, Josef
A1 - Richter, Christiane
A1 - Jungwirth, Jörg
A1 - Miranda, Luiza
A1 - Ammann, Rebecca
A1 - Caron, Jean‑François
A1 - de Bono, Victor
A1 - Monte, Renate
A1 - Navarrete, Iván
A1 - Eugenin, Claudia
A1 - Lombois‑Burger, Hélène
A1 - Baz, Bilal
A1 - Sinka, Maris
A1 - Sapata, Alise
A1 - Harbouz, Ilhame
A1 - Zhang, Yamei
A1 - Jia, Zijian
A1 - Kruger, Jacques
A1 - Mostert, Jean‑Pierre
A1 - Štefančič, Mateja
A1 - Hanžič, Lucija
A1 - Kaci, Abdelhak
A1 - Rahal, Said
A1 - Santhanam, Manu
A1 - Bhattacherjee, Shantanu
A1 - Snguanyat, Chalermwut
A1 - Arunothayan, Arun
A1 - Zhao, Zengfeng
A1 - Mai, Inka
A1 - Rasehorn, Inken Jette
A1 - Böhler, David
A1 - Freund, Niklas
A1 - Lowke, Dirk
A1 - Neef, Tobias
A1 - Taubert, Markus
A1 - Auer, Daniel
A1 - Hechtl, C. Maximilian
A1 - Dahlenburg, Maximilian
A1 - Esposito, Laura
A1 - Buswell, Richard
A1 - Kolawole, John
A1 - Isa, Muhammad Nura
A1 - Liu, Xingzi
A1 - Wang, Zhendi
A1 - Subramaniam, Kolluru
A1 - Bos, Freek
T1 - Mechanical properties of 3D printed concrete: a RILEM 304-ADC interlaboratory study – compressive strength and modulus of elasticity
N2 - Traditional construction techniques, such as in-situ casting and pre-cast concrete methods, have well-established testing protocols for assessing compressive strength and modulus of elasticity, including specific procedures for sample preparation and curing. In contrast, 3D concrete printing currently lacks standardized testing protocols, potentially contributing to the inconsistent results reported in previous studies. To address this issue, RILEM TC 304-ADC initiated a comprehensive interlaboratory study on the mechanical properties of 3D printed concrete. This study involves 30 laboratories worldwide, contributing 34 sets of data, with some laboratories testing more than one mix design. The compressive strength and modulus of elasticity were determined under three distinct conditions: Default, where each laboratory printed according to their standard procedure followed by water bath curing; Deviation 1, which involved creating a cold joint by increasing the time interval between printing layers; and Deviation 2, where the standard printing process was used, but the specimens were cured under conditions different from water bath. Some tests were conducted at two different scales based on specimen size—“mortar-scale” and “concrete-scale”—to investigate the size effect on compressive strength. Since the mix design remained identical for both scales, the only variable was the specimen size. This paper reports on the findings from the interlaboratory study, followed by a detailed investigation into the influencing parameters such as extraction location, cold joints, number of interlayers, and curing conditions on the mechanical properties of the printed concrete. As this study includes results from laboratories worldwide, its contribution to the development of relevant standardized testing protocols is critical.
KW - Additive manufacturing
KW - Digital fabrication
KW - Hardened concrete
KW - Compressive strength
KW - Young's modulus
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634672
DO - https://doi.org/10.1617/s11527-025-02688-9
SN - 1871-6873
VL - 58
IS - 5
SP - 1
EP - 30
PB - Springer Nature
AN - OPUS4-63467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heimann, Jan
A1 - Mustapha, Samir
A1 - Yilmaz, Bengisu
A1 - Prager, Jens
T1 - Guided Waves in Composite Overwrapped Pressure Vessels and Considerations for Sensor Placement Toward Structural Health Monitoring—An Experimental Study
N2 - The utilization of composite overwrapped pressure vessels (COPVs) to store hydrogen, especially at high pressures, is gaining more popularity due to their lightweight design and high storage density, offering significant economic advantages. However, the presence of material defects or fatigue can lead to critical failures, requiring an innovative and robust approach to ensure safe operation and system integrity. Developing a continuous structural health monitoring (SHM) system for COPVs can provide comprehensive realtime information about their condition, facilitating a shift away from periodic inspections.
This study scrutinizes the behavior of guided waves (GWs) within COPVs to design a sensor ,network for damage detection and localization. First, the dispersive and multimodal propagation behavior of GWs is experimentally investigated. Subsequently, important parameters for the network design are derived and finally a sensor network consisting of 15 piezoelectric transducers is designed to cover the entire cylindrical area. The effectiveness is then evaluated experimentally by placing artificial defects on the surface of the COPV. The multi-layered dataset of GW signals was analyzed using both commonly used ultrasonic features (e.g., amplitude, frequency, time of flight) as well as statistical features (kurtosis, skewness, variance, etc.). These features were utilized to compute a damage index, and the effectiveness of the detection performance was assessed using receiver operating characteristic curves. It can be seen that some features are more sensitive and robust under varying experimental conditions. The results show that ultrasonic GW SHM system is a promising solution for damage detection and localization in COPVs.
KW - Composite Overwrapped Pressure Vessels
KW - Guided Waves
KW - Structural Health Monitoring
KW - Sensors Placement
KW - Damage Detection
KW - Damage Localization
KW - Elastic Wave
KW - Testing Methodologies
KW - Ultrasonics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625239
DO - https://doi.org/10.1115/1.4067667
SN - 2572-3898
VL - 8
IS - 3
SP - 031007-1
EP - 031007-13
PB - The American Society of Mechanical Engineers (ASME)
CY - New York, USA
AN - OPUS4-62523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rasmussen, H. K.
A1 - Fasano, A.
A1 - Stajanca, Pavol
A1 - Woyessa, G.
A1 - Schukar, Marcus
A1 - Bang, O.
T1 - Mechanical characterization of drawn Zeonex, Topas, polycarbonate and PMMA microstructured polymer optical fibres
N2 - The mechanical stress-strain behaviour of polymer optical fibres (POFs) drawn from various materials was measured, both before and after temperature annealing of the POFs. The POFs were drawn from PMMA (GEHR), Zeonex (480R), PC (Makrolon LED2245) and two different grades of Topas (8007S-04 and 5013S-04). With fibre drawing stresses at or above the elastic (uniaxial extensional) plateau modulus, the polymer chains in the POFs have a high degree of alignment, which has a large impact on fibre mechanical behaviour. The testing was performed at straining rates ranging from 0.011%/s, to 1.1%/s for the un-annealed fibres and a straining rate of 1.1%/s for the annealed ones. The elastic modulus of the tested POFs showed no sensitivity toward variation of straining rate. In the case of Topas 5013S-04 and PMMA, the producer-reported values are the same as the one obtained here for the POFs both before and after annealing. The drawn POFs made of Zeonex, PC, and Topas 8007S-04 exhibit larger elastic modulus than the respective materials in the bulk form. The elastic modulus of these fibres is reduced upon annealing by 10-15%, but still remains above the producer-reported values for the bulk polymers. In the nonlinear elastic region, only the PC POF is statistically unaffected by the changes in the straining rate, while Topas 8007S-04 POF shows insensitivity to the straining rate until 3% strain. All other changes affect the stress-strain curves. The annealing flattens all stress-strain curves, making the fibres more sensitive to yield.
KW - Polymer optical fibres
KW - Mechanical characterization
KW - Stree-strain curve
KW - PMMA
KW - Topas
KW - Polycarbonate
KW - Zeonex
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464163
DO - https://doi.org/10.1364/OME.8.003600
SN - 2159-3930
VL - 8
IS - 11
SP - 3600
EP - 3614
PB - Optical Society of America
CY - Washington, DC
AN - OPUS4-46416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adamus, A.
A1 - Ali, I.
A1 - Vasileiadis, V.
A1 - Al-Hileh, L.
A1 - Lisec, Jan
A1 - Frank, M.
A1 - Seitz, G.
A1 - Engel, N.
T1 - Vincetoxicum arnottianum modulates motility features and metastatic marker expression in pediatric rhabdomyosarcoma by stabilizing the actin cytoskeleton
N2 - Background: Prevention of metastatic invasion is one of the main challenges in the treatment of alveolar rhabdomyosarcoma. Still the therapeutic options are limited. Therefore, an anti-tumor screening was initiated focusing on the anti-metastatic and anti-invasion properties of selected medicinal plant extracts and phytoestrogens, already known to be effective in the prevention and treatment of different cancer entities.
Methods: Treatment effects were first evaluated by cell viability, migration, invasion, and colony forming assays on the alveolar rhabdomyosarcoma cell line RH-30 in comparison with healthy primary cells.
Results: Initial anti-tumor screenings of all substances analyzed in this study, identified the plant extract of Vincetoxicum arnottianum (VSM) as the most promising candidate, harboring the highest anti-metastatic potential. Those significant anti-motility properties were proven by a reduced ability for migration (60%), invasion (99%) and colony formation (61%) under 48 h exposure to 25 μg/ml VSM. The restricted motility features were due to an induction of the stabilization of the cytoskeleton – actin fibers were 2.5-fold longer and were spanning the entire cell. Decreased proliferation (PCNA, AMT, GCSH) and altered metastasis (e. g. SGPL1, CXCR4, stathmin) marker expression on transcript and protein level confirmed the significant lowered tumorigenicity under VSM treatment. Finally, significant alterations in the cell metabolism were detected for
25 metabolites, with levels of uracil, N-acetyl serine and propanoyl phosphate harboring the greatest alterations. Compared to the conventional therapy with cisplatin, VSM treated cells demonstrated a similar metabolic shutdown of the primary cell metabolism. Primary control cells were not affected by the VSM treatment.
Conclusions: This study revealed the VSM root extract as a potential, new migrastatic drug candidate for the putative treatment of pediatric alveolar rhabdomyosarcoma with actin filament stabilizing properties and accompanied by a marginal effect on the vitality of primary cells.
KW - Mass Spectroscopy
KW - Metabolomics
KW - Cancer
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533530
DO - https://doi.org/10.1186/s12906-021-03299-x
VL - 21
IS - 1
PB - Springer Nature
AN - OPUS4-53353
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Mohring, Wencke
A1 - Hesse, René
A1 - Agudo Jácome, Leonardo
A1 - Stephan-Scherb, C.
T1 - Early material damage in equimolar CrMnFeCoNi in mixed oxidizing/sulfiding hot gas atmosphere
N2 - The challenges to use more varied fuels at medium and high temperatures above 500 °C need to be addressed by tuning the materials toward a better resistance against increased corrosion. As a first step the corrosion processes need to be better understood, especially in the case of the unavoidable and highly corrosive sulfur-based gases. Herein, oxidation/sulfidation of an equimolar CrMnFeCoNi high-entropy alloy is studied at an early stage after hot gas exposure at 600 °C for 6 h in 0.5% SO2 and 99.5% Ar. The oxidation process is studied by means of X-ray diffraction, scanning and transmission electron microscopy, and supported by thermodynamic calculations. It is found that the sulfur does not enter the bulk material but interacts mainly with the fast-diffusing manganese at grain boundary triple junctions at the alloy surface. Submicrometer scaled Cr–S–O-rich phases close to the grain boundaries complete the sulfur-based phase formation. The grains are covered in different Fe-, Mn-, and Cr-based spinels and other oxides.
KW - High entropy alloy
KW - Sulfiding
KW - Corrosion
KW - Transmission electron microscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543495
DO - https://doi.org/10.1002/adem.202101573
SN - 1527-2648
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54349
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lisec, Jan
A1 - Kobelt, D.
A1 - Walther, W.
A1 - Mokrizkij, M.
A1 - Grötzinger, C.
A1 - Jaeger, Carsten
A1 - Baum, K.
A1 - Simon, M.
A1 - Wolf, J.
A1 - Beindorf, N.
A1 - Brenner, W.
A1 - Stein, U.
T1 - Systematic Identification of MACC1-Driven Metabolic Networks in Colorectal Cancer
N2 - MACC1 is a prognostic and predictive metastasis biomarker for more than 20 solid Cancer entities. However, its role in cancer metabolism is not sufficiently explored. Here, we report on how MACC1 impacts the use of glucose, glutamine, lactate, pyruvate and fatty acids and show the comprehensive analysis of MACC1-driven metabolic networks. We analyzed concentrationdependent changes in nutrient use, nutrient depletion, metabolic tracing employing 13C-labeled substrates, and in vivo studies. We found that MACC1 permits numerous effects on cancer
metabolism. Most of those effects increased nutrient uptake. Furthermore, MACC1 alters metabolic pathways by affecting metabolite production or turnover from metabolic substrates. MACC1 supports use of glucose, glutamine and pyruvate via their increased depletion or altered distribution within metabolic pathways. In summary, we demonstrate that MACC1 is an important regulator of metabolism in cancer cells.
KW - Mass Spectroscopy
KW - Metabolomics
KW - Cancer
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533526
DO - https://doi.org/10.3390/cancers13050978
VL - 13
IS - 5
SP - 1
EP - 22
PB - MDPI Journal Cancers
AN - OPUS4-53352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grauel, Bettina
A1 - Würth, Christian
A1 - Homann, C.
A1 - Krukewitt, Lisa
A1 - Andresen, Elina
A1 - Roik, Janina
A1 - Recknagel, Sebastian
A1 - Haase, M.
A1 - Resch-Genger, Ute
T1 - Volume and surface effects on two-photonic and three-photonic processes in dry co-doped upconversion nanocrystals
N2 - Despite considerable advances in synthesizing high-quality core/shell upconversion (UC) nanocrystals (NC; UCNC) and UCNC photophysics, the application of near-infrared (NIR)-excitable lanthanide-doped UCNC in the life and material sciences is still hampered by the relatively low upconversion luminescence (UCL) of UCNC of small size or thin protecting shell. To obtain deeper insights into energy transfer and surface quenching processes involving Yb3+ and Er3+ ions, we examined energy loss processes in differently sized solid core NaYF4 nanocrystals doped with either Yb3+ (YbNC; 20% Yb3+) or Er3+ (ErNC; 2% Er3+) and co-doped with Yb3+ and Er3+ (YbErNC; 20% Yb3+ and 2% Er3+) without a surface protection shell and coated with a thin and a thick NaYF4 shell in comparison to single and co-doped bulk materials. Luminescence studies at 375 nm excitation demonstrate backenergy transfer (BET) from the 4G11/2 state of Er3+ to the 2F5/2 state of Yb3+, through which the red Er3+ 4F9/2 state is efficiently populated. Excitation power density (P)-dependent steady state and time-resolved photoluminescence measurements at different excitation and emission wavelengths enable to separate surface-related and volume-related effects for two-photonic and threephotonic processes involved in UCL and indicate a different influence of surface passivation on the green and red Er3+ emission.
The intensity and lifetime of the latter respond particularly to an increase in volume of the active UCNC core. We provide a threedimensional random walk model to describe these effects that can be used in the future to predict the UCL behavior of UCNC.
KW - Nano
KW - Nanomaterial
KW - Upconversion
KW - Nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Pphotophysics
KW - Lifetime
KW - Sensor
KW - Excitation
KW - Power density
KW - Single particle
KW - Brightness
KW - NIR
KW - Mechanism
KW - Modeling
KW - Simulation
KW - Energy transfer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535317
DO - https://doi.org/10.1007/s12274-021-3727-y
SN - 1998-0124
VL - 15
IS - 3
SP - 2362
EP - 2373
PB - Springer
AN - OPUS4-53531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Recknagel, Sebastian
A1 - Bresch, Harald
A1 - Kipphardt, Heinrich
A1 - Resch-Genger, Ute
A1 - Koch, Matthias
A1 - Rosner, M.
T1 - Trends in selected fields of reference material production
N2 - For more than 110 years, BAM has been producing reference materials for a wide range of application fields. With the development of new analytical methods and new applications as well as continuously emerging more stringent requirements of laboratory accreditation with regard to quality control and metrological traceability, the demand and requirements for reference materials are increasing. This trend article gives an overview of general developments in the field of reference materials as well as developments in selected fields of application in which BAM is active. This includes inorganic and metal analysis, gas analysis, food and consumer products, and geological samples. In addition to these more traditional fields of application, developments in the areas of optical spectroscopy, particulary fluorescence methods, and nanomaterials are considered.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - Reference material
KW - ISO REMCO
KW - Gas analysis
KW - Food
KW - Nanomaterials
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548407
DO - https://doi.org/10.1007/s00216-022-03996-7
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - Topical collection: Analytical methods and applications in the materials and life sciences
SP - 4281
EP - 4289
PB - Springer
CY - Berlin
AN - OPUS4-54840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maisuls, I.
A1 - Wang, Cui
A1 - Gutierrez Suburu, M. E.
A1 - Wilde, S.
A1 - Daniliuc, C.-G.
A1 - Brunink, D.
A1 - Doltsinis, N. L.
A1 - Ostendorp, S.
A1 - Kösters, J.
A1 - Resch-Genger, Ute
A1 - Strassert, C. A.
T1 - Ligand-controlled and nanoconfinement-boosted luminescence employing Pt(II) and Pd(II) complexes: from color-tunable aggregation-enhanced dual emitters towards self-referenced oxygen reporters
N2 - In this work, we describe the synthesis, structural and photophysical characterization of four novel Pd(II) and Pt(II) complexes bearing tetradentate luminophoric ligands with high photoluminescence quantum yields (FL) and long excited state lifetimes (s) at room temperature, where the results were interpreted by means of DFT calculations. Incorporation of fluorine atoms into the tetradentate ligand favors aggregation and thereby, a shortened average distance between the metal centers, which provides accessibility to metal–metal-to-ligand charge-transfer (3MMLCT) excimers acting as red-shifted Energy traps if compared with the monomeric entities. This supramolecular approach provides an elegant way to enable room-temperature phosphorescence from Pd(II) complexes, which are otherwise quenched by a thermal population of dissociative states due to a lower ligand field splitting. Encapsulation of These complexes in 100 nm-sized aminated polystyrene nanoparticles enables concentration-controlled aggregation-enhanced dual emission. This phenomenon facilitates the tunability of the absorption and emission colors while providing a rigidified environment supporting an enhanced FL up to about 80% and extended s exceeding 100 ms. Additionally, these nanoarrays constitute rare examples for selfreferenced oxygen reporters, since the phosphorescence of the aggregates is insensitive to external influences, whereas the monomeric species drop in luminescence lifetime and intensity with increasing triplet molecular dioxygen concentrations (diffusion-controlled quenching).
KW - Fluorescence
KW - Multiplexing
KW - Lifetime
KW - Bead
KW - Particle
KW - Dye
KW - Barcoding
KW - Encoding
KW - Quantum yield
KW - Label
KW - Reporter
KW - Pd(II)
KW - Pt(II)
KW - Complex
KW - NMR
KW - X-ray
KW - Sythesis
KW - Aggregation
KW - Monomer
KW - Color
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525288
DO - https://doi.org/10.1039/d0sc06126c
VL - 12
IS - 9
SP - 3270
EP - 3281
PB - Royal Society of Chemistry
AN - OPUS4-52528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rietsch, P.
A1 - Sobottka, S.
A1 - Hoffmann, Katrin
A1 - Hildebrandt, P.
A1 - Sarkar, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - Identification of the Irreversible Redox Behavior of Highly Fluorescent Benzothiadiazoles
N2 - Redox switches are applied in various fields of research, including molecular lifts, electronic devices and sensors. Switching the absorbance between UV and Vis/NIR by redox processes is of interest for applications in light harvesting or biomedicine.
Here, we present a series of push-pull benzothiadiazole derivatives with high fluorescence quantum yields in solution and in the crystalline solid state. Spectroelectrochemical analysis reveals the switching of UV-absorption in the neutral state to Vis/NIR absorption in the reduced state. We identify the partial irreversibility of the switching process, which appears to be reversible on the cyclic voltammetry timescale.
KW - Redox switch
KW - Electrochemistry
KW - Dye
KW - Fluorescence
KW - Absorption
KW - Sensor
KW - Benzothiadiazole
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520865
DO - https://doi.org/10.1002/cptc.202000050
SN - 2367-0932
VL - 4
IS - 9
SP - 668
EP - 673
PB - Wiley Online Library
AN - OPUS4-52086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Potopnyk, M.
A1 - Mech-Piskorz, J.
A1 - Angulo, G.
A1 - Ceborska, M.
A1 - Luboradzki, R.
A1 - Andresen, Elina
A1 - Gajek, A.
A1 - Wisniewska, A.
A1 - Resch-Genger, Ute
T1 - Aggregation/Crystallization-Induced Emission in Naphthyridine-Based Carbazolyl-Modified Donor-Acceptor Boron Dyes Tunable by Fluorine Atoms
N2 - Four donor-acceptor boron difluoride complexes based on the carbazole electron donor and the [1,3,5,2]oxadiazaborinino[3,4-a][1,8]naphthyridine acceptor were designed, synthesized, and systematically spectroscopically investigated in solutions, in the solid states, and dye-doped polymer films. The dyes exhibit an intense blue to red solid-state emission with photoluminescence quantum yields of up to 56% in pure dye samples and 86% in poly(methyl methacrylate) films. All boron complexes show aggregation-induced emission and reversible mechanofluorochromism. The optical properties of these dyes and their solid state luminescence can be tuned by substitution pattern, i.e., the substituents at the naphthyridine unit. Exchange of CH3- for CF3-groups does not only increase the intramolecular charge transfer character, but also provides a crystallization-induced emission enhancement.
KW - Spectroscopy
KW - Dye
KW - Luminescence
KW - Sensor
KW - Fluorescence
KW - Quantum yield
KW - Lifetime
KW - Quality assurance
KW - Synthesis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597426
DO - https://doi.org/10.1002/chem.202400004
SN - 0947-6539
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-59742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, P.
A1 - Morales-Marquez, R.
A1 - Cervas, G.
A1 - Hernandez Medel, A.
A1 - Ogayar, M. P.
A1 - Jimenez de Aberasturi, D.
A1 - de Isidro-Gomez, A. I.
A1 - Torres-Padro, A.
A1 - Palomares, F. J.
A1 - Garcia-Orrit, S.
A1 - Sousa, C. T.
A1 - Espinosa, A.
A1 - Telle, H. H.
A1 - Ortgies, D. H.
A1 - Vega-Mayoral, V.
A1 - Cabanillas-Gonzalez, J.
A1 - Rodriguez, E. M.
A1 - Resch-Genger, Ute
A1 - Wegner, Karl David
A1 - Juarez, B. H.
T1 - The role of temperature in the photoluminescence quantum yield (PLQY) of Ag2S-based nanocrystals
N2 - Highly emissive Ag2S nanocrystals (NCs) passivated with a gradated shell incorporating Se and Zn were synthesized in air, and the temperature dependence of their photoluminescence quantum yield (PLQY) was quantified in both organic and aqueous media at B1200 nm. The relevance of this parameter, measured at physiological temperatures, is highlighted for applications that rely on the near infrared (NIR) photoluminescence of NCs, such as deep NIR imaging or luminescence nanothermometry. Hyperspectral NIR imaging shows that Ag2S-based NCs with a PLQY in organic media of about 10% are inefficient for
imaging at 40 8C through 20 mm thick tissue with low laser irradiation
power densities. In contrast, water-transferred Ag2S-based NCs with an
initial PLQY of 2% in water exhibit improved robustness against temperature changes, enabling improved imaging performance.
KW - Quantum dots
KW - Ag2S
KW - Fluorescence
KW - Nanomaterial design
KW - Advanced nanomaterials
KW - Shortwave infrared (SWIR)
KW - Temperature sensing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613877
DO - https://doi.org/10.1039/D4MH01016G
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Krappe, Alexander R.
A1 - Fürstenwerth, Paul C.
A1 - Brosius, Amelie L.
A1 - Fasting, Carlo
A1 - Hoffmann, Kurt F.
A1 - Resch-Genger, Ute
A1 - Eigler, Siegfried
A1 - Steinhauer, Simon
A1 - Riedel, Sebastian
T1 - Luminescent Perhalofluoro Trityl Radicals
N2 - In this proof-of-concept study, we show that polyfluorinated trityl radicals with the, to this date, highest fluorination grade can be accessed in quantitative yields in a straightforward manner starting from the perfluorinated trityl cation. The trityl skeleton is functionalized with trimethylsilyl halides to yield perhalofluoro trityl cations, which are subsequently reduced using commercial zinc powder. In this way, we prepare three perhalofluoro trityl radicals and analyze the impact of the fluorine ligands on their electro-optical properties, revealing some interesting trends. In comparison to literature-known polychlorinated trityl radicals, the new polyfluorinated derivatives exhibit substantially higher fluorescence quantum yields, longer luminescence lifetimes, and an expanded emission range that extends into the yellow spectral region. They further display enhanced photostability under light irradiation. In radical-stained polystyrene nanoparticles, an additional broad emission band in the red−NIR wavelength region is observed, which is attributed to excimer formation. Finally, the stability of the new radicals is investigated under ambient conditions, showing the slow conversion with atmospheric oxygen yielding the respective peroxides, which are characterized by single-crystal X-ray diffraction. All in all, our study extends the present scope of luminescent trityl radicals, as the functionalization of the perfluorinated cationic precursor unlocks the path toward a vast variety of polyfluorinated trityl radicals.
KW - Dye
KW - Fluorescence
KW - Radical
KW - Synthesis
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Polarity
KW - Polymer
KW - Solvatchromism
KW - Excimer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647973
DO - https://doi.org/10.1021/jacs.5c16418
SN - 0002-7863
VL - 147
IS - 46
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-64797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sommerfeld, Thomas
A1 - Riedel, Juliane
A1 - Lisec, Jan
A1 - Mauch, Tatjana
A1 - Richter, Silke
A1 - Koch, Matthias
T1 - Development of a certified reference material for per- and polyfluoroalkyl substances (PFAS) in textiles
N2 - Per- and polyfluoroalkyl substances (PFASs) are a large group of emerging organic pollutants that contaminate the environment, food, and consumer products. Textiles and other outdoor products are a major source of PFAS exposure due to their water-repellent impregnations. Determination of PFASs in textiles is increasingly important for enhancing their contribution to the circular economy. While maximum levels and restrictions exist for certain key compounds under the Stockholm Convention on Persistent Organic Pollutants and the REACH regulation, certified reference materials (CRMs) are not currently available. To address this issue, the first CRM for determining PFASs in outdoor textiles (BAM-B003) was developed. It fully complies with the requirements of ISO 17034 and ISO 33405. This work presents the entire process of CRM development process, including preparation, a homogeneity study, a stability study, and value assignment. Certification was based on an in-house study at BAM using liquid chromatography tandem mass spectrometry (LC–MS/MS) with stable isotope dilution analysis (SIDA). The certified mass fractions of 18 PFASs range widely from 0.46 to 69 µg/kg, with a prevalence of PFOA (69 µg/kg), PFOS (41 µg/kg) and PFHxA (35 µg/kg) exceeding legal limits. BAM-B003 is intended for analytical quality control and contributes to improving the chemical safety of textiles and strengthening the circular economy.
KW - Reference Material
KW - PFAS
KW - Textiles
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641040
DO - https://doi.org/10.1007/s00216-025-06098-2
SN - 1618-2642
SP - 1
EP - 9
PB - Springer Science and Business Media LLC
AN - OPUS4-64104
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sommerfeld, Thomas
A1 - Jung, Christian
A1 - Riedel, Juliane
A1 - Mauch, Tatjana
A1 - Sauer, Andreas
A1 - Koch, Matthias
T1 - Development of a certified reference material for the determination of polycyclic aromatic hydrocarbons (PAHs) in rubber toy
N2 - Polycyclic aromatic hydrocarbons (PAHs) are a large group of priority organic pollutants, which contaminate environmental compartments, food, and consumer products as well. Due to their frequent occurrence associated with elevated Levels of PAHs, plastic and rubber parts of consumer products and toys are particular sources of exposure. Although European maximum levels exist for eight carcinogenic PAHs in consumer products and toys according to REACH Regulation (EC) No. 1907/2006, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of PAHs in rubber toys (BAM-B001) was developed according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented.
The assignment of the certified mass fractions was based upon in-house study at BAM using stable isotope Dilution analysis (SIDA) gas chromatography mass spectrometry (GC–MS). The obtained values were confirmed by the results of two interlaboratory comparison (ILC) studies with more than 50 expert laboratories from Germany and China. The mass fractions of 14 PAHs including all REACH and GS mark regulated compounds were certified ranging between 0.2 and 15.4 mg/
kg accompanied by expanded uncertainties (coverage factor k = 2). In addition, informative values were determined for 4 PAHs, mainly due to higher uncertainties and/or lack of ILC data for confirmation. BAM-B001 is intended for analytical quality control particularly based on the AfPS GS 2019:01 PAK method and contributes to improve the chemical safety of consumer products including toys.
KW - PAHs
KW - Consumer Products
KW - Toys
KW - Chemical Safety
KW - Certified reference material
KW - Quality assurance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539920
DO - https://doi.org/10.1007/s00216-021-03796-5
VL - 414
IS - 15
SP - 4369
EP - 4378
PB - Springer
AN - OPUS4-53992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Recknagel, Sebastian
A1 - Koch, Matthias
A1 - Köppen, Robert
A1 - Buttler, Sabine
A1 - Penk, Sibylle
A1 - Mauch, Tatjana
A1 - Sommerfeld, Thomas
A1 - Witt, Angelika
T1 - Development of certified reference materials for the determination of cadmium and acrylamide in cocoa
N2 - Since 1 January 2019 a maximum content of 0.6 mg kg−1 cadmium (Cd) in cocoa powder sold to the final consumer or as an ingredient in sweetened cocoa powder sold to the final consumer (drinking chocolate) is set by the Commission Regulation (EU) No. 488/2014. Monitoring compliance with the specified limit value requires analytical measuring methods and reference materials for quality control. However, suitable certified reference materials intended for quality assurance and quality control purposes are still lacking. Therefore, three cocoa reference materials (ERM®-BD513, ERM®-514 and ERM®-515) were developed according to the requirements of ISO 17034 and the recommendations of ISO Guide 35. The whole process of reference material development, including material preparation, assessment of homogeneity and stability, characterisation and value assignment is presented. The assignment of the certified mass fractions was based upon an interlaboratory comparison study involving 19 expert laboratories for Cd and 12 laboratories for acrylamide. The certified mass fractions and expanded uncertainties (k = 2) of the reference materials were (0.181 ± 0.009) mg kg−1 Cd (ERM®-BD513), (0.541 ± 0.024) mg kg−1 Cd (ERM®-BD514) and (0.690 ± 0.029) mg kg−1 Cd (ERM®-BD515). Acrylamide contents are given for information.
KW - Certified reference material
KW - Quality assurance
KW - Cocoa
KW - Cadmium
KW - Acrylamide
KW - Food analysis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508656
DO - https://doi.org/10.1007/s00216-020-02719-0
SN - 1618-2642
SN - 1618-2650
VL - 412
IS - 19
SP - 4659
EP - 4668
PB - Springer
CY - Berlin
AN - OPUS4-50865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Wegner, Karl David
A1 - Fischer, C.
A1 - Resch-Genger, Ute
T1 - Exploring Simple Particle-Based Signal Amplification Strategies in a Heterogeneous Sandwich Immunoassay with Optical Detection
N2 - Heterogeneous sandwich immunoassays are widely used for biomarker detection in bioanalysis and medical diagnostics. The high analyte sensitivity of the current “gold standard” enzyme-linked immunosorbent assay (ELISA) originates from the signal-generating enzymatic amplification step, yielding a high number of optically detectable reporter molecules. For future point-of-care testing (POCT) and point-of-need applications, there is an increasing interest in more simple detection strategies that circumvent time-consuming and temperature-dependent enzymatic reactions. A common concept to aim for detection limits comparable to those of enzymatic amplification reactions is the usage of polymer nanoparticles (NP) stained with a large number of chromophores. We explored different simple NP-based signal amplification strategies for heterogeneous sandwich immunoassays
that rely on an extraction-triggered release step of different types of optically detectable reporters. Therefore, streptavidinfunctionalized polystyrene particles (PSP) are utilized as carriers for (i) the fluorescent dye coumarin 153 (C153) and (ii) hemin (hem) molecules catalyzing the luminol reaction enabling chemiluminescence (CL) detection. Additionally, (iii) NP labeling with hemin-based microperoxidase MP11 was assessed. For each amplification approach, the PSP was first systematically optimized regarding size, loading concentration, and surface chemistry. Then, for an immunoassay for the inflammation marker C- eactive protein (CRP), the analyte sensitivity achievable with optimized PSP
ystems was compared with the established ELISA concept for photometric and CL detection. Careful optimization led to a limit of detection (LOD) of 0.1 ng/mL for MP11-labeled PSP and CL detection, performing similarly well to a photometric ELISA (0.13 ng/mL), which demonstrates the huge potential of our novel assay concept.
KW - Nanoparticle
KW - Fluorescence
KW - Immunoassay
KW - Quality assurance
KW - Antibody
KW - Polymer
KW - Dye
KW - Signal enhancement
KW - CRP
KW - Biosensing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597853
DO - https://doi.org/10.1021/acs.analchem.3c03691
SN - 1520-6882
VL - 96
IS - 13
SP - 5078
EP - 5085
PB - American Chemical Society
CY - Columbus, Ohio
AN - OPUS4-59785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Grabolle, Markus
A1 - Pauli, Jutta
A1 - Spieles, Monika
A1 - Resch-Genger, Ute
T1 - Relative and absolute determination of fluorescence quantum yields of transparent samples
N2 - Luminescence techniques are among the most widely used detection methods in the life and material sciences. At the core of these methods is an ever-increasing variety of fluorescent reporters (i.e., simple dyes, fluorescent labels, probes, sensors and switches) from different fluorophore classes ranging from small organic dyes and metal ion complexes, quantum dots and upconversion nanocrystals to differently sized fluorophore-doped or fluorophore-labeled polymeric particles. A key parameter for fluorophore comparison is the fluorescence quantum yield (Φf), which is the direct measure for the efficiency of the conversion of absorbed light into emitted light. In this protocol, we describe procedures for relative and absolute determinations of Φf values of fluorophores in transparent solution using optical methods, and we address typical sources of uncertainty and fluorophore class-specific challenges. For relative determinations of Φf, the sample is analyzed using a conventional fluorescence spectrometer. For absolute determinations of Φf, a calibrated stand-alone integrating sphere setup is used. To reduce standard-related uncertainties for relative measurements, we introduce a series of eight candidate quantum yield standards for the wavelength region of ~350950 nm, which we have assessed with commercial and custom-designed instrumentation. With these protocols and standards, uncertainties of 5–10% can be achieved within 2 h.
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-294202
DO - https://doi.org/10.1038/nprot.2013.087
SN - 1754-2189
SN - 1750-2799
VL - 8
IS - 8
SP - 1535
EP - 1550
PB - Nature Publishing Group
CY - Basingstoke
AN - OPUS4-29420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herter, Sven-Oliver
A1 - Koch, Matthias
A1 - Haase, Hajo
T1 - First Synthesis of Ergotamine-13CD3 and Ergotaminine-13CD3 from Unlabeled Ergotamine
N2 - Ergot alkaloids (EAs) formed by Claviceps fungi are one of the most common food contaminants worldwide, affecting cereals such as rye, wheat, and barley. To accurately determine the level of contamination and to monitor EAs maximum levels set by the European Union, the six most common EAs (so-called priority EAs) and their corresponding epimers are quantified using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The quantification of EAs in complex food matrices without appropriate internal tandards is challenging but currently carried out in the standard method EN 7425:2021 due to their commercial unavailability. To address the need for isotopically labeled EAs, we focus on two semi-synthetic approaches for the synthesis of these reference standards. Therefore, we investigate the feasibility of the N6-demethylation of native ergotamine to yield norergotamine, which can subsequently be remethylated with an isotopically labeled methylating reagent, such as iodomethane (13CD3-I), to yield isotopically labeled ergotamine and its C8-epimer ergotaminine. Testing the isotopically labeled ergotamine/-inine against native ergotamine/-inine with HPLC coupled to high-resolution HR-MS/MS proved the structure of ergotamine-13CD3 and ergotaminine-13CD3. Thus, for the first time, we can describe their synthesis from unlabeled, native ergotamine. Furthermore, this approach is promising as a universal way to synthesize other isotopically labeled EAs.
KW - Reference Material
KW - HPLC-MS/MS
KW - Mycotoxins
KW - Standards
KW - Organic Synthesis
KW - Isotope
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600167
DO - https://doi.org/10.3390/toxins16040199
VL - 16
IS - 4
SP - 1
EP - 12
PB - MDPI
AN - OPUS4-60016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Osiopova, Viktoriia
A1 - Tavernaro, Isabella
A1 - Ge, L.
A1 - Kitzmann, W. R.
A1 - Heinze, K.
A1 - Reithofer, M. R.
A1 - Resch-Genger, Ute
T1 - Complete protection of NIR-luminescent molecular rubies from oxygen quenching in air by L-arginine-mediated silica nanoparticles
N2 - The application of emerging luminophores such as near-infrared (NIR) emissive complexes based on earth-abundant chromium as central ion and triplet-triplet annihilation upconversion (TTA-UC) systems in air as optical reporters for bioimaging or photonic materials for energy conversion requires simple and efficient strategies for their complete protection from uminescence quenching by oxygen. Therefore, we explored the influence of sol–gel synthesis routes on the oxygen protection efficiency of the resulting core and core/shell silica nanoparticles (SiO2 NPs), utilizing the molecular ruby-type luminophores CrPF6 ([Cr(ddpd)2](PF6)3; ddpd = N,N'-dimethyl-N,N'-dipyridin-2-ylpyridin-2,6-diamine) and CrBF4 ([Cr(ddpd)2](BF4)3) with their oxygendependent, but polarity-, proticity-, viscosity-, and concentration-independent luminescence as optical probes for oxygen permeability. The sol–gel chemistry routes we assessed include the classical Stöber method and the underexplored Larginine approach, which relies on the controlled hydrolysis of tetraethoxysilane (TEOS) in a biphasic cyclohexane/water system with the catalyst L-arginine. As demonstrated by luminescence measurements of air- and argon-saturated dispersions of CrPF6- and CrBF4-stained SiO2 NPs of different size and particle architecture, utilizing the luminescence decay kinetics of argon-saturated solutions of CrPF6 and CrBF4 in acetonitrile (ACN) as benchmarks, only SiO2 NPs or shells synthesized by the L-arginine approach provided complete oxygen protection of the CrIII complexes under ambient conditions. We ascribe the different oxygen shielding efficiencies of the silica networks explored to differences in density and surface chemistry of the resulting nanomaterials and coatings, leading to different oxygen permeabilities. Our Larginine based silica encapsulation strategy can open the door for the efficient usage of oxygen-sensitive luminophores and TTA-UC systems as optical reporters and spectral shifters in air in the future.
KW - Quality assurance
KW - Fluorescence
KW - Quantification
KW - Advanced materials
KW - Nano
KW - Quantum yield
KW - NIR
KW - Characterization
KW - Electron microscopy
KW - Silica
KW - Synthesis
KW - Oxygen sensing
KW - Surface
KW - Doping
KW - Lifetime
KW - Cr(III) complex
KW - Shielding
KW - Sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638271
DO - https://doi.org/10.26599/NR.2025.94907241
SN - 1998-0000
VL - 18
IS - 3
SP - 1
EP - 13
PB - SciOpen
AN - OPUS4-63827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Soyka, J. P.
A1 - Witte, J. F.
A1 - Wiesner, A.
A1 - Krappe, A. R.
A1 - Wehner, D.
A1 - Alnicola, N.
A1 - Paulus, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - [3]Radialene Fluorophores with pH-Switchable Emission and Stable Absorption Maxima
N2 - The first push–pull quino [3]radialene fluorescent dye is reported. Herein, the novel bis(dicyanomethylene)-[3]radialene electron acceptor is connected to a benzimidazole donor. With protonation, a substantial redshift of fluorescence wavelength is observed, while the absorption maximum remains stable. This process is accompanied with an increased fluorescence quantum yield to about 70%. Further, the findings are explained by a combined experimental and theoretical approach, and it is found that vibronic coupling plays a crucial role. This study highlights the yet unexplored potential of [3]radialene-based motifs for the design of environment-responsive fluorophores.
KW - DADQ
KW - Nanographene
KW - fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Quantum yield
KW - Photophysic
KW - pH
KW - Probe
KW - Sensor
KW - Lifetime
KW - Polarity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642147
DO - https://doi.org/10.1002/ejoc.202500669
SN - 1099-0690
SP - 1
EP - 6
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64214
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hartmann, Yannic
A1 - El Abbassi, Abdelouahad
A1 - Mayer, Bernhard
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Ester‐Aroyl‐S,N‐Ketene Acetals with Solid‐State Luminescence: AIEgens from Sequential Three‐Component Desymmetrization
N2 - AbstractDi(hetero)aroyl dichlorides are desymmetrized upon sequential reaction with alcohols and 2‐methyl N‐benzyl thiazolium salts within the course of a one‐pot three‐component reaction yielding ester‐substituted aroyl‐S,N‐ketene acetals under mild conditions in good yields. A prerequisite for the concise one‐pot process is the different nucleophilicity of the alcohols and in situ generated S,N‐ketene acetals. The resulting compounds are merocyanines with dominant charge‐transfer absorption bands which are fluorescent in the solid state, but not in solution. In water/ethanol solvent mixtures of increasing water content, the water‐insoluble dyes display typical aggregation‐induced emission (AIE) characteristics. The water fraction inducing AIE as well as the emission color, and fluorescence quantum yield (Φf) of the aggregated dyes can be controlled by the alcohol part of the ester moiety. Encapsulation into polystyrene nanoparticles can lead to a considerable increase of the fluorescence quantum yield Φf to 30% as shown for a representatively chosen dye revealing the highest Φf of 11% within the dye series in the water/ethanol mixtures and enabling the usage of these dyes as fluorescent reporters in aqueous environments.
KW - Dye
KW - Fluorescence
KW - Aggregation
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Probe
KW - Sensor
KW - Lifetime
KW - Polarity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642400
DO - https://doi.org/10.1002/chem.202502071
SN - 0947-6539
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reichenauer, F.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Boden, P.
A1 - Ugur, N.
A1 - Báez-Cruz, R.
A1 - Kalmbach, J.
A1 - Carrella, L. M.
A1 - Rentschler, E.
A1 - Ramanan, C.
A1 - Niedner-Schatteburg, G.
A1 - Gerhards, M.
A1 - Seitz, M.
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Strongly Red-Emissive Molecular Ruby [Cr(bpmp)2]3+ Surpasses [Ru(bpy)3]2+
N2 - Gaining chemical control over the thermodynamics and kinetics of photoexcited states is paramount to an efficient and sustainable utilization of photoactive transition metal complexes in a plethora of technologies. In contrast to energies of charge Transfer states described by spatially separated orbitals, the energies of spinflip states cannot straightforwardly be predicted as Pauli Repulsion and the nephelauxetic effect play key roles. Guided by multireference quantum chemical calculations, we report a novel highly luminescent spin-flip emitter with a quantum chemically predicted blue-shifted luminescence. The spin-flip emission band of the chromium complex [Cr(bpmp)2]3+ (bpmp = 2,6-bis(2-pyridylmethyl) pyridine) shifted to higher energy from ca. 780 nm observed for known highly emissive chromium(III) complexes to 709 nm. The photoluminescence quantum yields climb to 20%, and very long excited state lifetimes in the millisecond range are achieved at room temperature in acidic D2O solution. Partial ligand deuteration increases the quantum yield to 25%. The high excited state energy of [Cr(bpmp)2]3+ and its facile reduction to [Cr(bpmp)2]2+ result in a high excited state redox potential. The ligand’s methylene bridge acts as a Brønsted acid quenching the luminescence at high pH. Combined with a pH-insensitive chromium(III) emitter, ratiometric optical pH sensing is achieved with single wavelength excitation. The photophysical and Ground state properties (quantum yield, lifetime, redox potential, and acid/base) of this spin-flip complex incorporating an earth-abundant metal surpass those of the classical precious metal [Ru(α-diimine)3]2+ charge transfer complexes, which are commonly employed in optical sensing and photo(redox) catalysis, underlining the bright future of these molecular ruby analogues.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530548
DO - https://doi.org/10.1021/jacs.1c05971
VL - 143
IS - 30
SP - 11843
EP - 11855
PB - ACS Publications
AN - OPUS4-53054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auxillos, J.
A1 - Crouigneau, R.
A1 - Li, Y.-F.
A1 - Dai, Y.
A1 - Stigliani, A.
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Sandelin, A.
A1 - Marie, R.
A1 - Pedersen, S. F.
T1 - Spatially resolved analysis of microenvironmental gradient impact on cancer cell phenotypes
N2 - Despite the physiological and pathophysiological significance of microenvironmental gradients, e.g., for diseases such as cancer, tools for generating such gradients and analyzing their impact are lacking. Here, we present an integrated microfluidic-based workflow that mimics extracellular pH gradients characteristic of solid tumors while enabling high-resolution live imaging of, e.g., cell motility and chemotaxis, and preserving the capacity to capture the spatial transcriptome. Our microfluidic device generates a pH gradient that can be rapidly controlled to mimic spatiotemporal microenvironmental changes over cancer cells embedded in a 3D matrix. The device can be reopened allowing immunofluorescence analysis of selected phenotypes, as well as the transfer of cells and matrix to a Visium slide for spatially resolved analysis of transcriptional changes across the pH gradient. This workflow is easily adaptable to other gradients and multiple cell types and can therefore prove invaluable for integrated analysis of roles of microenvironmental gradients in biology.
KW - Bioimaging
KW - Fluorescence
KW - Cell
KW - Cancer
KW - Method
KW - Microfluids
KW - Model
KW - Calibration
KW - Sensor
KW - Ph
KW - Probe
KW - Workflow
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604631
DO - https://doi.org/10.1126/sciadv.adn3448
VL - 19
IS - 18
SP - 1
EP - 17
AN - OPUS4-60463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Nirmalananthan-Budau, Nithiya
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
T1 - Analyzing the surface of functional nanomaterials — how to quantify the total and derivatizable number of functional groups and ligands
N2 - Functional nanomaterials (NM) of different size, shape, chemical composition, and surface chemistry are of increasing relevance for many key technologies of the twenty-first century. This includes polymer and silica or silica-coated nanoparticles (NP) with covalently bound surface groups, semiconductor quantum dots (QD), metal and metal oxide NP, and lanthanide-based NP with coordinatively or electrostatically bound ligands, as well as surface-coated nanostructures like micellar encapsulated NP. The surface chemistry can significantly affect the physicochemical properties of NM, their charge, their processability and performance, as well as their impact on human health and the environment. Thus, analytical methods for the characterization of NM surface chemistry regarding chemical identification, quantification, and accessibility of functional groups (FG) and surface ligands bearing such FG are of increasing importance for quality control of NM synthesis up to nanosafety. Here, we provide an overview of analytical methods for FG analysis and quantification with special emphasis on bioanalytically relevant FG broadly utilized for the covalent attachment of biomolecules like proteins, peptides, and oligonucleotides and address methodand material-related challenges and limitations. Analytical techniques reviewed include electrochemical titration methods, optical assays, nuclear magnetic resonance and vibrational spectroscopy, as well as X-ray based and thermal analysis methods, covering the last 5–10 years. Criteria for method classification and evaluation include the need for a signal-generating label, provision of either the total or derivatizable number of FG, need for expensive instrumentation, and suitability for process and production control during NM synthesis and functionalization.
KW - Functional group quantification
KW - Surface ligand
KW - Nanomaterial
KW - Optical detection
KW - Electrochemical titration
KW - Nanosafety (Safe-by-design)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533597
DO - https://doi.org/10.1007/s00604-021-04960-5
VL - 188
IS - 10
SP - 1
EP - 28
PB - Springer Nature
AN - OPUS4-53359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Cui
A1 - Kitzmann, W.R.
A1 - Weigert, Florian
A1 - Förster, Ch.
A1 - Wang, X.
A1 - Heintze, K.
A1 - Resch-Genger, Ute
T1 - Matrix Effects on Photoluminescence and Oxygen Sensitivity of a Molecular Ruby
N2 - The molecular ruby analogue [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) exhibits near infrared (NIR) emission with a high photoluminescence (PL) quantum yield ΦPL of 11 % and a lifetime of 898 μs in deaerated water at room temperature. While ligand-based control of the photophysical properties has received much attention, influences of the counter anions and microenvironment are still underexplored. In this study, the luminescence properties of the molecular ruby were systematically examined for the counter anions Cl−, Br−, [BF4]−, [PF6]−, [BPh4]−, and [BArF24]− in acetonitrile (MeCN) solution, in crystals, and embedded into polystyrene nanoparticles (PSNP). Stern-Volmer analyses of the oxygen quenching studies in the intensity and lifetime domain showed the highest oxygen sensitivity of the complexes with the counter anions of [BF4]− and [BArF24]−, which also revealed the longest luminescence lifetimes. Embedding [Cr(ddpd)2][PF6]3 in PSNPs and shielding with poly(vinyl alcohol) yields a strongly NIR-emissive oxygen-insensitive material with a record ΦPL of 15.2 % under ambient conditions.
KW - Fluorescence
KW - Sensor
KW - Oxygen
KW - Quantum yield
KW - Quality assurance
KW - Complex
KW - Cr(III)
KW - Lifetime
KW - Ligand
KW - Solid state
KW - X-Ray analysis
KW - Structure-property relationship
KW - Nano
KW - Polymer
KW - Particle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546057
DO - https://doi.org/10.1002/cptc.202100296
SN - 2367-0932
VL - 6
IS - 6
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, C.
A1 - Schäferling, Michael
A1 - Resch-Genger, Ute
A1 - Gradzielski, M.
T1 - Solvothermal Synthesis of Lanthanide-doped NaYF4 Upconversion
N2 - Lanthanide-doped NaYF4 upconversion nano- and microcrystals were synthesized via a facile solvothermal approach. Thereby, the influence of volume ratios of ethylene glycol (EG)/H2O, molar ratios of NH4F/RE3+ (RE3+ represents the total amount of Y3+ and rare-earth dopant ions), Gd3+ ion contents, types of activator dopant ions, and different organic co-solvents on the crystal phase, size, and morphology of the resulting particles were studied systematically. A possible formation mechanism for the growth of crystals of different morphology is discussed. Our results show that the transition from the α- to the β-phase mainly depends on the volume ratio of EG/H2O and the molar ratio of NH4F/RE3+, while the morphology and size could be controlled by the type of organic co-solvent and Gd3+ dopant ions. Furthermore, the reaction time has to be long enough to convert α-NaYF4 into β-NaYF4 during the growth process to optimize the upconversion luminescence. The formation of larger β-NaYF4 crystals, which possess a higher upconversion luminescence than smaller particles, proceeds via intermediates of smaller crystals of cubic structure. In summary, our synthetic approach presents a facile route to tailor the size, Crystal phase, morphology, and luminescence features of upconversion
materials.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Photoluminescence
KW - Lanthanide
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Surface chemistry
KW - Single particle
KW - Brightness
KW - NIR
KW - Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520307
DO - https://doi.org/10.1002/cnma.202000564
VL - 7
IS - 2
SP - 174
EP - 183
PB - Wiley
AN - OPUS4-52030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bastos, V.
A1 - Oskoei, P.
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Oliveira, H.
T1 - Stability, dissolution, and cytotoxicity of NaYF4‑upconversion nanoparticles with different coatings
N2 - Upconversion nanoparticles (UCNPs) have attracted considerable attention owing to their unique photophysical properties. Their utilization in biomedical applications depends on the understanding of their transformations under physiological conditions and their potential toxicity. In this study, NaYF4: Yb,Er UCNPs, widely used for luminescence and photophysical studies, were modified with a set of four different coordinatively bound surface ligands, i.e., citrate, alendronate (AA), ethylendiamine tetra(methylene phosphonate) (EDTMP), and poly(maleic anhydride-alt-1-octadecene) (PMAO), as well as silica coatings with two different thicknesses. Subsequently, the aging-induced release of fluoride ions in water and cell culture media and their cytotoxic profile to human keratinocytes were assessed in parallel to the cytotoxic evaluation of the ligands, sodium fluoride and the lanthanide ions. The cytotoxicity studies of UCNPs with different surface modifications demonstrated the good biocompatibility of EDTMP-UCNPs and PMAO-UCNPs, which is in line with the low amount of fluoride ions released from these samples. An efficient prevention of UCNP dissolution and release of cytotoxic ions, as well as low cytotoxicity was also observed for UCNPs with a sufficiently thick silica shell. Overall, our results provide new insights into the
understanding of the contribution of surface chemistry to the stability, dissolution behavior, and cytotoxicity of UCNPs. Altogether, the results obtained are highly important for future applications of UCNPs in the life sciences and bioimaging studies.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Excitation power density
KW - Surface chemistry
KW - Coating
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544681
DO - https://doi.org/10.1038/s41598-022-07630-5
SN - 2045-2322
VL - 12
SP - 1
EP - 13
PB - Springer Nature
CY - London
AN - OPUS4-54468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, F.
A1 - Rietsch, P.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Weigert, Florian
A1 - Götze, J. P.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
A1 - Paulus, B.
T1 - Aggregation-induced emission leading to two distinct emissive species in the solid-state structure of high-dipole organic chromophores
N2 - The concept of aggregation-induced emission represents a means to rationalise photoluminescence of usually nonfluorescent excimers in solid-state materials. In this publication, we study the photophysical properties of selected diaminodicyanoquinone (DADQ) derivatives in the solid state using a combined approach of experiment and theory. DADQs are a class of high-dipole organic chromophores promising for applications in non-linear optics and light-harvesting devices. Among the compounds investigated, we find both aggregation-induced emission and aggregation-caused quenching effects rationalised by calculated energy transfer rates. Analysis of fluorescence spectra and lifetime measurements provide the interesting result that (at least) two emissive species seem to contribute to the photophysical properties of DADQs. The main emission peak is notably broadened in the long-wavelength limit and exhibits a blue-shifted shoulder. We employ high-level quantum-chemical methods to validate a molecular approach to a solid-state problem and show that the complex emission features of DADQs can be attributed to a combination of H-type aggregates, monomers, and crystal structure defects.
KW - Fluorescence
KW - Optical probe
KW - Dye
KW - Photophysics
KW - Theory
KW - Quantum yield
KW - Mechanism
KW - Quantum chemistry
KW - Modelling
KW - Aggregation
KW - Lifetime
KW - Single particle
KW - Microscopy
KW - Solid
KW - Crystal
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531138
DO - https://doi.org/10.1039/d1cp02534a
SP - 1
EP - 9
PB - Royal Society of Chemistry
AN - OPUS4-53113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andresen, Elina
A1 - Radunz, Sebastian
A1 - Resch-Genger, Ute
T1 - Novel PET-Operated Rosamine Sensor Dyes with Substitution Pattern-Tunable pKa Values and Temperature Sensitivity
N2 - We present the synthesis and characterization of a family of regioisomerically pure pH-sensitive rosamine fluorophores consisting of xanthene fluorophore cores, which determine the dyes’ photophysical properties such as excitation/emission wavelength, fluorescence quantum yield, and fluorescence lifetime, and differently substituted phenol moieties. The hydroxyl substituent of the phenol moiety introduces a pH sensitivity of the dyes’ fluorescence exploiting a photoinduced electron transfer (PET), that leads to a protonation-induced switching ON of the rosamine emission. Rational tuning of the pKa value of the rosamine fluorescence between 4 to 9 is achieved by altering the substitution pattern and degree of bromination of the phenolic subunits. Additionally, a temperature sensitivity of the fluorescence quantum yield is introduced or suppressed based upon the degree of rigidity of the xanthene scaffold.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Rosamine
KW - Synthesis
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurancemechanism
KW - temperature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530562
DO - https://doi.org/10.1039/d1nj02505h
VL - 45
IS - 31
SP - 13934
EP - 13940
PB - Royal Society of Chemistry
AN - OPUS4-53056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le Guevel, X.
A1 - Wegner, Karl David
A1 - Würth, Christian
A1 - Baulin, V. A.
A1 - Musnier, B.
A1 - Josserand, V.
A1 - Resch-Genger, Ute
A1 - Koll, J-C
T1 - Tailoring the SWIR emission of gold nanoclusters by surface ligand rigidification and their application in 3D bioimaging
N2 - The influence of solvent polarity and surface ligand rigidification on the SWIR emission profile of gold nanoclusters with an anistropic surface was investigated. A strong enhancement of the SWIR emission band at 1200 nm was observed when measuring in different local environments: in solution, in polymer composites, and in solids. SWIR in vivo imaging of mice assisted by deep learning after intravenous administration of these gold nanoclusters provides high definition pseudo-3D views of vascular blood vessels.
KW - Nano
KW - Nanomaterial
KW - Metal cluster
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - SWIR
KW - Ligand
KW - Gold
KW - Mechanism
KW - Charge transfer
KW - Enhancement strategy
KW - Imaging
KW - Application
KW - Contrast agent
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543582
DO - https://doi.org/10.1039/D1CC06737K
VL - 58
IS - 18
SP - 2967
EP - 2970
PB - RSC
AN - OPUS4-54358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Puertollano, Daniel
A1 - Duncan, Hadyn
A1 - Abad-Somovilla, Antonio
A1 - Abad-Fuentes, Antonio
A1 - Rurack, Knut
T1 - Competitive cytometry-based immunoassay for patulin determination in apple juice
N2 - Patulin is a mycotoxin that is frequently found in apples and apple-derived products. Given the potential harm it can cause to humans, maximum levels for patulin in food have been set worldwide. Conventional methods for the detection of patulin are often time-consuming or lack sensitivity. In this study, a novel cytometry approach based on specific monoclonal antibodies is presented. These high-affinity binders do not target patulin itself, but a stable derivative (adduct) that is rapidly obtained in an aqueous medium at room temperature. To develop the assay, a specific fluorescent competitor was designed and synthesized. After optimizing the assay conditions, including the concentration of the fluorescent competitor and of the antibody bound to polystyrene-silica core–shell microparticles, a detection limit of 0.03 μg L-1 in buffer was achieved. Finally, validation according to Commission Regulation (EU) 2023/2782 demonstrated that apple juice samples spiked with patulin at 25 or 50 μg L-1 (permissible limits set by the EU) were properly scored as non-compliant without any additional treatment other than a simple dilution step in buffer. The developed assay offers several key advantages, including rapid analysis, high sensitivity and specificity, and the potential for multiplexing, making it a promising analytical tool for routine monitoring of patulin contamination in food.
KW - Bead-based assay
KW - Cytometry
KW - Derivatization
KW - Mycotoxin
KW - Patulin
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627659
DO - https://doi.org/10.1016/j.microc.2025.113287
SN - 1095-9149
VL - 212
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-62765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Mohring, Wencke
A1 - Schneider, Mike
A1 - Laplanche, Guillaume
A1 - Hagen, Sebastian Peter
A1 - Stephan‐Scherb, Christiane
T1 - High‐Temperature Oxidation of the CrFeNi Medium‐Entropy Alloy
N2 - The isothermal high‐temperature oxidation behavior of the equiatomic CrFeNi medium‐entropy alloy is a key issue that determines whether this material is suited for high‐temperature application. In this view, the understanding of the long‐term behavior is even more crucial than short‐term corrosion effects. Herein, a single‐phase CrFeNi alloy of the face‐centered‐cubic structure is exposed to synthetic air at 1000, 1050, and 1100 °C for 24, 100, and 1000 h and its oxidation behavior is systematically compared to that of 316L steel, which shows a surprising initial oxidation stabilization during early stages. The oxidation rate of CrFeNi is parabolic at 1000 °C (with a parabolic constant kp = 1.4·10−5 mg−2 cm−4 s−1) and 1050 °C (kp = 2.7·10−5 mg−2 cm−4 s−1), but breakaway oxidation occurs at 1100 °C after 4 h of exposure. In all cases, the oxide scales are found to (at least) partially spall off. Chromium diffuses outward to form a Cr2O3 layer at the gas/oxide interface, and a thin layer of (Cr, Fe, Ni)3O4 is identified at the oxide/alloy interface. Unlike the 316L alloy, which contains more Mn and Fe, the CrFeNi alloy does not show any catastrophic oxidation behavior at the investigated conditions.
KW - Corrosion
KW - Medium-entropy alloy
KW - Scanning electron microscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636672
DO - https://doi.org/10.1002/adem.202500400
SN - 1438-1656
SP - 1
EP - 14
PB - Wiley VHC-Verlag
AN - OPUS4-63667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Puertollano, Daniel
A1 - Tobias, Charlie
A1 - Bell, Jérémy
A1 - Abad-Somovilla, A.
A1 - Abad-Fuentes, A.
A1 - Rurack, Knut
T1 - Superparamagnetic Bead-Based Microfluidic Fluoroimmunoassay Platform for Rapid Ochratoxin A Detection in Flour
N2 - Simplification and reduction of time and costs are the primary goals in the development and use of onsite methods in diagnostics and food safety. To facilitate the transition from laboratory techniques to simple, miniaturized devices, we have developed a modular microfluidic platform. This platform integrates a competitive fluorescence immunoassay on the surface of superparamagnetic beads, serving as a complementary technique to traditional cytometry assays. In the first chip module, a fast competitive reaction (5 min) occurs, after which the particles are retained in the second module. This module consists of a PDMS chip and a permanent magnet, allowing only the fluorescent competitor to reach the detection module. Ochratoxin A (OTA) was chosen as the model analyte for device development, using fluorescein-labeled OTA as a competitor. The system efficiently separates particles, with OTA concentration directly correlated to the amount of fluorescent competitor remaining in solution after the competitive reaction. This innovative setup allows to perform rapid measurements with small sample volumes in a short time (10 min), achieving a limit of detection for OTA of 1.2 μg L–1. The system was successfully applied to the accurate determination of OTA in wheat flour spiked at regulatorily relevant concentrations. Using this device, conventional cytometry immunoassays can be seamlessly transformed into user-friendly, miniaturized analytical methods at reduced cost for applications outside of a laboratory directly at the point of need.
KW - Bead-based assay
KW - Fluorescence
KW - Immunoassay
KW - Microfluidics
KW - mycotoxins
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638472
DO - https://doi.org/10.1021/acssensors.5c01119
SN - 2379-3694
SP - 1
EP - 10
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-63847
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Agudo Jácome, Leonardo
A1 - Thompsom, Sean
A1 - Schneider, Judy
T1 - On the transferability of post-processing heat treatments designed for PBF-LB IN718 alloys to directed energy deposition specimens
N2 - Many processes are being developed for metal additive manufacturing (AM) which vary by their heat source and feedstock. The use of directed energy deposition (DED) is growing due to its ability to build larger structures outside of a contained powder bed chamber. However, the only standard exclusively for post-build heat treatment of AM IN718 is ASTM standard F3055-14a, developed for powder bed fusion (PBF). This study evaluates the applicability of this current heat treatment standard to AM IN718 specimens produced using two methods of DED: laser-blown powder (LP)-DED and arc-wire (AW)-DED. Electron microscopy and X-ray diffraction techniques were used to characterize the specimens in the as-built condition and after the full heat treatment (FHT) specified in F3055. No evidence of remaining Laves phase was observed in the two DED specimens after the FHT. Yield strengths for the DED specimens were 1049 MPa for FHT AW-DED and 1096 MPa for LP-DED, higher than the minimum stated for PBF-LB IN718 of 920 MPa. The size, morphology, inter-spacing, and diffraction patterns of the γ´ and γ´´ strengthening precipitates are found to be similar for both DED processes. Differences were observed in the microstructure evolution where the F3055 heat treatments resulted in partial recrystallization of the grain structure, with a higher content of annealing twins observed in the AW-DED. These microstructural differences correlate with differences in the resulting elongation to failure. Thus, it is proposed that variations in heat treatments are needed for optimizing IN718 produced by different AM processes.
KW - Additive manufacturing variants
KW - Directed energy deposition (DED)
KW - Post-process heat treatments
KW - SEM-EBSD and TEM microscopy
KW - XRD phase analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628165
DO - https://doi.org/10.1007/s00170-025-15386-1
SN - 1433-3015
VL - 137
IS - 7-8
SP - 3949
EP - 3965
PB - Springer Science and Business Media LLC
AN - OPUS4-62816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weinel, Kristina
A1 - Hahn, Marc Benjamin
A1 - Lubk, Axel
A1 - González Martínez, Ignacio Guillermo
A1 - Büchner, Bernd
A1 - Agudo Jácome, Leonardo
T1 - Nanoparticle Synthesis by Precursor Irradiation with Low-Energy Electrons
N2 - Nanoparticles (NPs) and their fabrication routes are intensely studied for their wide range of application in optics, chemistry, and medicine. Γ-ray and ion irradiation of precursor matter are established methods that facilitate tailored NP synthesis without complicated chemistry. Here, we develop and explore NP synthesis based on irradiating precursor microparticles with low-energy electron beams. We specifically demonstrate the fabrication of plasmonic gold nanoparticles of sizes between 3 and 350 nm on an amorphous SiOx substrate using a 30 kV electron beam. By detailed comparison with electron scattering simulations and thermodynamic modeling, we reveal the dominant role of inelastic electron–matter interaction and subsequent localized heating for the observed vaporization of the precursor gold microparticles. This general principle suggests the suitability of electron-beam irradiation for synthesizing NPs of a wide class of materials.
KW - Gold Nanoparticle
KW - Scanning Electron Microscopy
KW - In situ irradiation
KW - Thermodynamic modelling
KW - Heat Transfer
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627609
DO - https://doi.org/10.1021/acsanm.4c06033
SN - 2574-0970
VL - 8
IS - 10
SP - 4980
EP - 4988
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-62760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Gawlitza, Kornelia
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence
N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors.
KW - Fluorescence
KW - BODIPY probe
KW - Molecularly Imprinted Polymers
KW - Sensor Materials
KW - Dyes
KW - Water analysis
KW - Advanced materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629
DO - https://doi.org/10.1039/D3MA00476G
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Verhassel, Alejandra
A1 - Kimani, Martha Wamaitha
A1 - Gidwani, Kamlesh
A1 - Sandholm, Jouko
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Härkönen, Pirkko
T1 - Detection of Tn-antigen in breast and prostate cancer models by VVL-labeled red dye-doped nanoparticles
N2 - Aim: Fluorescence detection of breast and prostate cancer cells expressing Tn-antigen, a tumor marker, with Vicia villosa lectin (VVL)-labeled nanoparticles.
Materials & methods: Breast and prostate cancer cells engineered to express high levels of Tn-antigen and non-engineered controls were incubated with VVL-labeled or unlabeled red dye-doped silica-coated polystyrene nanoparticles. The binding to cells was studied with flow cytometry, confocal microscopy, and electron microscopy.
Results: Flow cytometry showed that the binding of VVL-labeled nanoparticles was significantly higher to Tn-antigen-expressing cancer cells than controls. Confocal microscopy demonstrated that particles bound to the cell surface. According to the correlative light and electron microscopy the particles bound mostly as aggregates.
Conclusion: VVL-labeled nanoparticles could provide a new tool for the detection of Tn-antigen-expressing breast and prostate cancer cells.
KW - Breast cancer cells
KW - Fluorescence detection
KW - Lectin labeling
KW - Prostate cancer cells
KW - Silica-coated polystyrene nanoparticles
KW - Tn-antigen
KW - VVL
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613451
DO - https://doi.org/10.1080/17435889.2024.2405454
SN - 1743-5889
VL - 19
SP - 2463
EP - 2478
PB - Taylor & Francis
CY - London
AN - OPUS4-61345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feng, Wen
A1 - Schulz, Johannes
A1 - Wolf, Daniel
A1 - Pylypenko, Sergii
A1 - Gemming, Thomas
A1 - Weinel, Kristina
A1 - Agudo Jácome, Leonardo
A1 - Büchner, Bernd
A1 - Lubk, Axel
T1 - Secondary electron emission from gold microparticles in a transmission electron microscope: comparison of Monte Carlo simulations with experimental results
N2 - We measure the electron beam-induced current to analyze the electron-induced secondary electron (SE) emission from micron-sized gold particles illuminated by 80 and 300 keV electrons in a transmission electron microscope. A direct comparison of the experimental and simulated SE emission (SEE) employing Monte Carlo scattering simulations based on the GEANT4 toolkit yields overall good agreement with a noticeable discrepancy arising from the shortcoming of the GEANT4 scattering cross sections in the low-loss regime. Thus, the electron beam-induced current analysis allows to quantify the inelastic scattering including SEE in the transmission electron microscope and provides further insight into the charging mechanisms.
KW - Electron beam-induced current
KW - Transmission electron microscopy
KW - Secondary electron emission
KW - Secondary electron yield
KW - Gold micronoparticle
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622557
DO - https://doi.org/10.1088/1361-6463/ad9840
VL - 58
IS - 8
SP - 1
EP - 7
PB - IOP Publishing
CY - Bristol, GB
AN - OPUS4-62255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weinel, Kristina
A1 - Schultz, Johannes
A1 - Kalady, Mohammed Fayis
A1 - Wolf, Daniel
A1 - Agudo Jácome, Leonardo
A1 - Lubk, Axel
T1 - Fabrication of 2-dimensional disordered assemblies of gold nanoparticles and investigation of localized surface plasmon resonances
N2 - Interaction of electromagnetic waves, such as electron beams or light, with conductive material can lead to localized surface plasmon resonances (LSPRs) where the incoming energy can be deposited in a collective excitation of electrons of the conduction band, which in turn can result in coherent localized plasmon oscillations. LSPR in metallic nanostructures, such as nanoparticles (NPs), which are sensitive to geometry, material composition and environment, are currently utilized in a wide range of applications, such as surface-enhanced Raman spectroscopy, plasmonic wave guides, improved solar cells, on-chip particle accelerators and nanoantennas. A host of studies that focus on plasmonic NPs ranging from single NPs with several shapes (cubic, spherical, tetrahedral) over 1D assemblies of NPs such as chains, to ordered 2D assemblies of NPs show an increase of the complexity regarding the hybridization behavior of LSPRs eventually lead to delocalized Surface Plasmons. Furthermore, Anderson predicted in 1977 the absence of diffusion or delocalization of waves in disordered systems, which has been discussed as the underlying mechanism for LSPRs localization in disordered metallic thin films and ultrathin 2D networks. Our aim is to further develop these studies on the surface plasmon localization in disordered structures by (1) developing a novel NPs assembly fabrication method that allows fabricating disordered assemblies of NPs of a wide range of NPs sizes, and (2) probing the LSPR with high-resolution electron energy-loss spectroscopy (EELS). Moreover, the dominant dipolar interaction between the NPs, also facilitates an efficient numerical modeling of these systems, which in comparison with the experiments allows for an in-depth study of the impact of various geometric parameters as well as retardation and life-time damping on the observed localization behavior.
To synthesize 2D disordered assemblies of gold NPs on a TEM transparent silicon oxide substrate, a new synthesis routine was developed. This procedure is based on sublimation and redeposition of a gold microparticle precursor induced by an electron beam in a scanning electron microscope (SEM) operated at 30 kV. To characterize the assembly of synthesized NPs in terms of size, shape and spreading over the substrate, TEM measurements were conducted subsequently. To study LSPRs experimentally, EELS in scanning transmission electron microscopy (STEM) mode was carried out. The numerical modelling of LSPRs was performed using a self-consistent dipole model.
The synthesized 2D disordered gold NPs assemblies exhibit a gradient in the NPs mean size, which ranges from 100 nm close to the precursor location down to 2 nm at a distance of more than 20 µm from the precursor location. Additionally, the interparticle distance between the gold NPs increases with increasing distance to the precursor location.
The experimental investigation as well as the numerical simulation of the LSPRs demonstrate a localization behavior that decreases toward larger energies, which is driven by the disorder of the NPs assembly (mainly the random particle distance). That localization behavior stays in contrast to what was found in ultrathin 2D gold networks showing increasing of localization towards higher LSPRs energies. By varying the geometric parameters of the NPs assembly in the simulation, we could identify the NPs thickness as the parameter, that determines the energy-dependence of the localization. Specifically, a critical thickness of approx. 10 nm separates the two localization regimes, which correlates to the energy of the dipole mode resonance crucially depending on the thickness of the NPs.
2D disordered assemblies of gold NPs of a wide range of NPs sizes and distances can be synthesized directly on thin substrates facilitating structural characterization and EELS measurements in a TEM. It could be shown that such assemblies exhibit LSPRs with a localization behavior that may be tuned by the NPs sizes (including thickness) and interparticle distances. The proposed synthesis of random NPs assemblies opens new avenues for fundamental studies on Anderson localization in disordered plasmonic structures as well as its applications such as surface-enhanced Raman spectroscopy where localization behavior must be tuned to specific wave lengths.
T2 - 17th European Microscopy Congress (EMC 2024)
CY - Copenhagen, Denmark
DA - 26.08.2024
KW - Scanning electron microscopy
KW - Gold nanoparticle synthesis
KW - Disordered assemblies
KW - Localized surface plasmon resonances
KW - Transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618330
DO - https://doi.org/10.1051/bioconf/202412932007
VL - 129
SP - 1
EP - 2
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-61833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paulisch-Rinke, M. C.
A1 - Manzoni, Anna Maria
A1 - Agudo Jácome, Leonardo
A1 - Vogel, F.
A1 - Reimers, W.
T1 - Influence of chemical composition on microstructure and mechanical properties in the extruded aluminum alloys 7021B and 7175
N2 - The aim of this study is to improve the mechanical properties of Al 7xxx series alloys by achieving the strengthening benefits typically provided by Cu while avoiding the formation of low-melting eutectic phases associated with excessive Cu content. This is accomplished through a tailored combination of alloying elements and optimized thermomechanical treatments.
Alloys 7021B (high Zn content) and 7175 (high Cu and Mg content) are analyzed and optimized threefold in this study: the heat treatment, the microstructural evolution and the mechanical properties are investigated by several methods and compared with the aim of improving the process parameters for subsequent application.
The peak-aging process is optimized via compression tests to overcome the strength-ductility trade-off. Microstructure and phase chemistry analyses by transmission electron microscopy and atom probe tomography enable a better understanding of the underlying morphological features such as the spatial distribution, and the chemical composition of the hardening phases. The mechanical properties of the peak-aged alloys are determined by compression and tensile tests. Both alloys exhibit very high strength – even by 7xxx series standards. It can be traced back to the dislocation movement: it is impeded both by homogeneously distributed cuttable Guinier–Preston zones in both alloys and by non-cuttable η’ precipitates.
As a result, we demonstrate that alloy 7021B offers novel possibilities for processing and industrial application: high strength, typically associated with Cu containing alloys, can also be obtained in Cu free alloys, if the Zn content is sufficiently high. We can thus suggest new opportunities for processing and industrial applications by reducing the risk of forming low-melting eutectic phases.
KW - Aluminium alloys
KW - Transmission electron microscopy
KW - Atom probe tomography
KW - Extrusion
KW - Mechanical properties
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640338
DO - https://doi.org/10.1016/j.matdes.2025.114649
SN - 0264-1275
VL - 258
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-64033
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller-Elmau, Johanna
A1 - Göbel, Artur
A1 - Junge, Paul
A1 - Müller, Julian
A1 - Rousseau, Tom
A1 - Görke, Oliver
A1 - Nikasch, Christian
A1 - Kiliani, Stefan
T1 - Thermal cycling of YAG infiltration and plasma sprayed coatings as environmental barrier coating on ceramic heat shields for use in hydrogen operating gas turbines
N2 - Environmental barrier coatings (EBC) are intended to protect alumina ceramic tiles in hot water vapor conditions, enabling gas turbines to operate with higher hydrogen content or even pure hydrogen. For these operating conditions, yttrium aluminum garnet (YAG) promises the highest protection against hydrolysis, which can be applied via atmospheric plasmaspraying (APS). To enhance the protection efficiency, the coating is combined with a prior infiltration of the base material. The obtained design acts as in-depth protection even if the coating exhibits cracks.
KW - Thermal shock
KW - Thermal cycles
KW - Environmental barrier coating (EBC)
KW - Water vapor corrosion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639829
DO - https://doi.org/10.1016/j.oceram.2025.100837
VL - 23
SP - 1
EP - 7
PB - Elsevier Ltd.
AN - OPUS4-63982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauli, Jutta
A1 - Ramírez, A.
A1 - Crasselt, C.
A1 - Schmidt, W.
A1 - Resch-Genger, Ute
T1 - Utilizing optical spectroscopy and 2',7'-difluorofluorescein to characterize the early stages of cement hydration
N2 - The increasingly sophisticated nature of modern, more environmentally friendly cementitious binders requires a better understanding and control particularly of the complex, dynamic processes involved in the early phase of cement hydration. In-situ monitoring of properties of a constantly changing system over a defined period of time calls for simple, sensitive, fast, and preferably also non-invasive methods like optical spectroscopy
KW - Flourescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Flourescin
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Mechanism
KW - Cement
KW - Concrete
KW - Building material
KW - Hydration
KW - Process monitoring
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537176
DO - https://doi.org/10.1088/2050-6120/ac2da0
SN - 2050-6120
VL - 10
IS - 1
SP - 2
EP - 13
PB - IOP Science
AN - OPUS4-53717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yanbaeva, M.
A1 - Soyka, J.
A1 - Holthoff, J. M.
A1 - Rietsch, P.
A1 - Engelage, E.
A1 - Ruff, A.
A1 - Resch-Genger, Ute
A1 - Weiss, R.
A1 - Eigler, S.
A1 - Huber, S. M.
T1 - Dimethylene-Cyclopropanide Units as Building Blocks for Fluorescence Dyes
N2 - Many organic dyes are fluorescent in solution. In the solid state, however, quenching processes often dominate, hampering material science applications such as light filters, light-emitting devices, or coding tags. We show that the dimethylene-cyclopropanides caffold can be used to form two structurally different types of chromophores, which feature fluorescence quantum yields up to 0.66 in dimethyl sulfoxide and 0.53 in
solids. The increased fluorescence in the solid state for compounds bearing malonate substituents instead of dicyanomethide ones is rationalized by the induced twist between the planes of the cyclopropanide core and a pyridine ligand.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Solvatochromism
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614931
DO - https://doi.org/10.1002/chem.202402476
VL - 30
IS - 56
SP - 1
EP - 7
PB - Chemistry - A European Journal
AN - OPUS4-61493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
A1 - Johnston, L. J.
A1 - Zou, S.
T1 - Nanoscale reference and test materials for the validation of characterization methods for engineered nanomaterials — current state, limitations, and needs
N2 - The rational design of engineered nanomaterials (NMs) with improved functionality and their increasing industrial application requires reliable, validated, and ultimately standardized characterization methods for their application-relevant, physicochemical key properties such as size, size distribution, shape, or surface chemistry. This calls for nanoscale (certified)
reference materials (CRMs; RMs) and well-characterized reference test materials (RTMs) termed also quality control (QC) samples, assessed, e.g., in interlaboratory comparisons, for the validation and standardization of commonly used characterization methods. Thereby, increasing concerns regarding potential risks of NMs are also addressed and the road for safe and
sustainable-by-design concepts for the development of new functional NMs and their use as nanomedicines is paved. With this respect, we will provide an overview of relevant international standardization and regulatory activities, definitions, and recommendations on characterization methods and review currently available organic or inorganic nanoscale CRMs, RMs, and RTMs, including their characterization or certification. In addition, we will highlight typical applications to streamline the regulatory approval process and improve manufacturability including the special challenges imposed by the colloidal nature and sometimes limited stability of NMs. Subsequently, we will critically assess the limitations of currently available nanoscale RMs and RTMs and address the gaps to be filled in the future such as the availability of NMs that come with reference data on properties other than commonly addressed particle size, such as surface chemistry or particle number concentration, or
more closely resemble commercially available formulations or address application-relevant matrices.
KW - Nano
KW - Particle
KW - Silica
KW - Quality assurance
KW - Reference material
KW - Review
KW - Surface chemistry
KW - Size
KW - Shape
KW - Particle number concentration
KW - Lipid nanoparticles
KW - Metal nanoparticles
KW - Liposomes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625746
DO - https://doi.org/10.1007/s00216-024-05719-6
SN - 1618-2650
SP - 1
EP - 21
PB - Springer
AN - OPUS4-62574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Labrador-Paez, Lucia, L.
A1 - Kankare, J.
A1 - Hyppanen, I.
A1 - Soukka, T.
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Widengren, J
A1 - Liu, H.
T1 - Frequency-Domain Method for Characterization of Upconversion Luminescence Kinetics
N2 - The frequency-domain (FD) method provides an alternative to the commonly used time-domain (TD) approach in characterizing the luminescence kinetics of luminophores, with its own strengths, e.g., the capability to decouple multiple lifetime components with higher reliability and accuracy. While extensively explored for characterizing luminophores with down-shifted emission, this method has not been investigated for studying nonlinear luminescent materials such as lanthanide-doped upconversion nanoparticles (UCNPs), featuring more complicated kinetics. In this work, employing a simplified rate-equation model representing a standard two-photon energy-transfer upconversion process, we thoroughly analyzed the response of the luminescence of UCNPs in the FD method. We found that the FD method can potentially obtain from a single experiment the effective decay rates of three critical energy states of the sensitizer/activator ions involved in the upconversion process. The validity of the FD method is demonstrated by experimental data, agreeing reasonably well with the results obtained by TD methods.
KW - Quality assurance
KW - Luminescence
KW - Method
KW - Quantitative spectroscopy
KW - Nano
KW - Particle
KW - Lifetime
KW - Method development
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597435
DO - https://doi.org/10.1021/acs.jpclett.3c00269
SP - 3436
EP - 3444
AN - OPUS4-59743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Bliesener, Lilly
A1 - Weiss, Tilman
A1 - Koch, Matthias
T1 - Marker Substances in the Aroma of Truffles
N2 - The aim of this study was to identify specific truffle marker substances within the truffle aroma. The aroma profile of different truffle species was analyzed using static headspace sampling with gas chromatography mass spectrometry analysis (SHS/GC-MS). Possible marker substances were identified, taking the additional literature into account. The selected marker substances were tested in an experiment with 19 truffle dogs. The hypothesis “If trained truffle dogs recognize the substances as supposed truffles in the context of an experiment, they can be regarded as specific” was made. As it would be nearly impossible to investigate every other possible emitter of the same compounds to determine their specificity, this hypothesis was a reasonable approximation. We were interested in the question of what it is the dogs actually search for on a chemical level and whether we can link their ability to find truffles to one or more specific marker substances. The results of the dog experiment are not as unambiguous as could have been expected based on the SHS/GC-MS measurements. Presumably, the truffle aroma is mainly characterized and perceived by dogs by dimethyl sulfide and dimethyl disulfide. However, as dogs are living beings and not analytical instruments, it seems unavoidable that one must live with some degree of uncertainty regarding these results.
KW - Truffle
KW - Volatile organic compounds;
KW - Gas chromatography
KW - Mass spectrometry
KW - Canine olfactometry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556116
DO - https://doi.org/10.3390/molecules27165169
SN - 1420-3049
VL - 27
IS - 16
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-55611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Koch, Matthias
T1 - On-Site Detection of Volatile Organic Compounds (VOCs)
N2 - Volatile organic compounds (VOCs) are of interest in many different fields. Among them are food and fragrance analysis, environmental and atmospheric research, industrial applications, security or medical and life science. In the past, the characterization of these compounds was mostly performed via sample collection and off-site analysis with gas chromatography coupled to mass spectrometry (GC-MS) as the gold standard. While powerful, this method also has several drawbacks such as being slow, expensive, and demanding on the user. For decades, intense research has been dedicated to find methods for fast VOC analysis on-site with time and spatial resolution. We present the working principles of the most important, utilized, and researched technologies for this purpose and highlight important publications from the last five years. In this overview, non-selective gas sensors, electronic noses, spectroscopic methods, miniaturized gas chromatography, ion mobility spectrometry and direct injection mass spectrometry are covered. The advantages and limitations of the different methods are compared. Finally, we give our outlook into the future progression of this field of research.
KW - Volatile organic compounds
KW - On-site detection
KW - Mobile analytics
KW - Sensors
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570885
DO - https://doi.org/10.3390/molecules28041598
VL - 28
IS - 4
SP - 1
EP - 19
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-57088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Eckert, J. G.
A1 - Elahi, T.
A1 - Lübkemann, F.
A1 - Hübner, Oskar
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Luminescence encoding of polymer microbeads with organic dyes and semiconductor quantum dots during polymerization
N2 - Luminescence-encoded microbeads are important tools for many applications in the life and material sciences that utilize luminescence detection as well as multiplexing and barcoding strategies. The preparation of such beads often involves the staining of premanufactured beads with molecular luminophores using simple swelling procedures or surface functionalization with layer-by-layer (LbL) techniques. Alternatively, these luminophores are sterically incorporated during the polymerization reaction yielding the polymer beads. The favorable optical properties of semiconductor quantum dots (QDs), which present broadly excitable, size-tunable, narrow emission bands and low photobleaching sensitivity, triggered the preparation of beads stained with QDs. However, the colloidal nature and the surface chemistry of these QDs, which largely controls their luminescence properties, introduce new challenges to bead encoding that have been barely systematically assessed. To establish a straightforward approach for the bead encoding with QDs with minimized loss in luminescence, we systematically assessed the incorporation of oleic acid/oleylamine-stabilized CdSe/CdS-core/shell-QDs into 0.5–2.5 μm-sized polystyrene (PS) microspheres by a simple dispersion polymerization synthesis that was first optimized with the organic dye Nile Red. Parameters addressed for the preparation of luminophore-encoded beads include the use of a polymer-compatible ligand such as benzyldimethyloctadecylammonium chloride (OBDAC) for the QDs, and crosslinking to prevent luminophore leakage. The physico-chemical and optical properties of the resulting beads were investigated with electron microscopy, dynamic light scattering, optical spectroscopy, and fluorescence microscopy. Particle size distribution, fluorescence quantum yield of the encapsulated QDs, and QD leaking stability were used as measures for bead quality. The derived optimized bead encoding procedure enables the reproducible preparation of bright PS microbeads encoded with organic dyes as well as with CdSe/CdS-QDs. Although these beads show a reduced photoluminescence quantum yield compared to the initially very strongly luminescent QDs, with values of about 35%, their photoluminescence quantum yield is nevertheless still moderate.
KW - Polymerization
KW - Quantum dots
KW - Microbeads
KW - Fluorescence
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553430
DO - https://doi.org/10.1038/s41598-022-16065-x
SN - 2045-2322
VL - 12
SP - 1
EP - 16
PB - Nature Publishing Group
CY - London
AN - OPUS4-55343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Clark, P.C.J
A1 - Andresen, Elina
A1 - Sear, M. J.
A1 - Favaro, M.
A1 - Girardi, L.
A1 - van de Krol, R.
A1 - Resch-Genger, Ute
A1 - Starr, D.E.
T1 - Quantification of the Activator and Sensitizer Ion Distributions in NaYF4:Yb3+, Er3+ Upconverting Nanoparticles Via Depth-Profiling with Tender X-Ray Photoemission
N2 - The spatial distribution and concentration of lanthanide activator and sensitizer dopant ions are of key importance for the luminescence color and efficiency of upconverting nanoparticles (UCNPs). Quantifying dopant ion distributions and intermixing, and correlating them with synthesis methods require suitable analytical techniques. Here, X-ray photoelectron spectroscopy depth-profiling with tender X-rays (2000–6000 eV), providing probe depths ideally matched to UCNP sizes, is used to measure the depth-dependent concentration ratios of Er3+ to Yb3+, [Er3+]/[Yb3+], in three types of UCNPs prepared using different reagents and synthesis methods. This is combined with data simulations and inductively coupled plasma-optical emission spectroscopy (ICP-OES) measurements of the lanthanide ion concentrations to construct models of the UCNPs’ dopant ion distributions. The UCNP sizes and architectures are chosen to demonstrate the potential of this approach. Core-only UCNPs synthesized with XCl3·6H2O precursors (β-phase) exhibit a homogeneous distribution of lanthanide ions, but a slightly surface-enhanced [Er3+]/[Yb3+] is observed for UCNPs prepared with trifluroacetate precursors (α-phase). Examination of Yb-core@Er-shell UCNPs reveals a co-doped, intermixed region between the single-doped core and shell. The impact of these different dopant ion distributions on the UCNP's optical properties is discussed to highlight their importance for UCNP functionality and the design of efficient UCNPs.
KW - Shell
KW - Nanomaterial
KW - Nano
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Excitation power density
KW - Surface
KW - Coating
KW - Core-shell
KW - XPS
KW - Intermixing
KW - HAXPES
KW - Method
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552075
DO - https://doi.org/10.1002/smll.202107976
SN - 1613-6813
SP - 1
EP - 13
PB - Wiley-VCH-Verlag
CY - Weinheim, Germany
AN - OPUS4-55207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, C.
A1 - Schwibbert, Karin
A1 - Gadicherla, A. K.
A1 - Thiele, Dorothea
A1 - Nirmalananthan-Budau, Nithiya
A1 - Laux, P.
A1 - Resch-Genger, Ute
A1 - Luch, A.
A1 - Tschiche, H. R.
T1 - Monitoring and imaging pH in biofilms utilizing a fluorescent polymeric nanosensor
N2 - Biofilms are ubiquitous in nature and in the man-made environment. Given their harmful effects on human health, an in-depth understanding of biofilms and the monitoring of their formation and growth are important. Particularly relevant for many metabolic processes and survival strategies of biofilms is their extracellular pH. However, most conventional techniques are not suited for minimally invasive pH measurements of living biofilms. Here, a fluorescent nanosensor is presented for ratiometric measurements of pH in biofilms in the range of pH 4.5–9.5 using confocal laser scanning microscopy. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with pH-inert dye Nile Red and is surface functionalized with a pH-responsive fluorescein dye. Its performance was validated by fluorometrically monitoring the time-dependent changes in pH in E. coli biofilms after glucose inoculation at 37 °C and 4 °C. This revealed a temperature-dependent decrease in pH over a 4-h period caused by the acidifying glucose metabolism of E. coli. These studies demonstrate the applicability of this nanosensor to characterize the chemical microenvironment in biofilms with fluorescence methods.
KW - Dye
KW - Fluorescence
KW - Signal enhancement
KW - Sensor
KW - Quantum yield
KW - Synthesis
KW - Nanoparticle
KW - Nano
KW - Polymer
KW - Ph
KW - Biofilm
KW - MIC
KW - Corrosion
KW - Microorganism
KW - Bacteria
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550751
DO - https://doi.org/10.1038/s41598-022-13518-1
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 10
PB - Nature Publishing Group
CY - London
AN - OPUS4-55075
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knoche, Lisa
A1 - Lisec, Jan
A1 - Koch, Matthias
T1 - Analysis of electrochemical and liver microsomal transformation products of lasalocid by LC/HRMS
N2 - Rationale: Lasalocid (LAS), an ionophore, is used in cattle and poultry farming as feed additive for its antibiotic and growth-promoting properties. Literature on transformation products (TP) resulting from LAS degradation is limited. So far, only hydroxylation is found to occur as the metabolic reaction during the LAS degradation. To investigate potential TPs of LAS, we used electrochemistry (EC) and liver microsome (LM) assays to synthesize TPs, which were identified using liquid chromatography high-resolution mass spectrometry (LC/HRMS).
Methods: Electrochemically produced TPs were analyzed online by direct coupling of the electrochemical cell to the electrospray ionization (ESI) source of a Sciex Triple-TOF high resolution mass spectrometer. Then, EC-treated LAS solution was collected and analyzed offline using LC/HRMS to confirm stable TPs and improve their annotation with a chemical structure due to informative MS/MS spectra. In a complementary approach, TPs formed by rat and human microsomal incubation were investigated using LC/HRMS. The resulting data were used to investigate LAS modification reactions and elucidate the chemical structure of obtained TPs.
Results: The online measurements identified a broad variety of TPs, resulting from modification reactions like (de-)hydrogenation, hydration, methylation, oxidation as well as adduct formation with methanol. We consistently observed different ion complexations of LAS and LAS-TPs (Na+; 2Na+ K+; NaNH4 +; KNH4 +). Two stable methylated EC-TPs were found, structurally annotated, and assigned to a likely modification reaction. Using LM incubation, seven TPs were formed, mostly by oxidation/hydroxylation. After the identification of LM-TPs as Na+-complexes, we identified LM-TPs as K+-complexes.
Conclusion: We identified and characterized TPs of LAS using EC- and LM-based methods. Moreover, we found different ion complexes of LAS-based TPs. This knowledge, especially the different ion complexes, may help elucidate the metabolic and environmental degradation pathways of LAS.
KW - Mass Spectrometry
KW - Electrochemistry
KW - ECR
KW - Lasalocid
KW - Ionophore
KW - Transformation products
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553919
DO - https://doi.org/10.1002/rcm.9349
VL - 36
IS - 18
SP - 1
EP - 10
PB - Wiley online library
AN - OPUS4-55391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koch, Matthias
A1 - Mauch, Tatjana
A1 - Riedel, Juliane
T1 - Development of a Hydrazine-Based Solid-Phase Extraction and Clean-Up Method for Highly Selective Quantification of Zearalenone in Edible Vegetable Oils by HPLC-FLD
N2 - Rapid, cost-efficient, and eco-friendly methods are desired today for routine analysis of the Fusarium mycotoxin zearalenone (ZEN) in edible vegetable oils. Liquid chromatography with fluorescence detection (HPLC-FLD) is commonly used to reliably control the specified ZEN maximum levels, which requires efficient sample clean-up to avoid matrix interferences. Therefore, a highly selective extraction and clean-up method based on reversible covalent hydrazine chemistry (RCHC) using hydrazine-functionalized silica was developed. This efficient solid-phase extraction (SPE) involves reversible hydrazone formation of ZEN with the hydrazine moiety covalently bound to a solid phase. Optimal conditions were achieved with 1 mL SPE cartridges filled with 400 mg of hydrazine-functionalized silica. The developed RCHC-SPE method was validated in an interlaboratory comparison study (ILC) with twelve participants analyzing six edible vegetable oils with a focus on maize oils. The derived method parameters (ZEN recovery 83%, repeatability 7.0%, and reproducibility 18%) meet the performance criteria of Commission Regulation (EC) No 401/2006. The developed RCHC-SPE-based HPLC-FLD method allows the reliable quantification of ZEN in the range of 47–494 μg/kg for different types of edible vegetable oils, also for matrix-reach native oils. Due to the high efficiency, the significantly reduced matrix load helps to extend the lifetime of analytical equipment. Furthermore, the re-useability of the RCHC-SPE cartridges contributes to an eco-friendly approach and reduced analysis costs. To our knowledge, this is the first report on ZEN quantification in edible vegetable oils based on manual RCHC-SPE cartridges. Due to its high performance, the developed RCHC-SPE method is a promising alternative to the current European standard method EN 16924:2017 (HPLC-FLD part).
KW - Mycotoxin
KW - Food
KW - Reversible covalent hydrazine chemistry (RCHC)
KW - Quantitative determination
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554812
DO - https://doi.org/10.3390/toxins14080549
VL - 14
IS - 8
PB - MDPI
CY - Basel
AN - OPUS4-55481
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stein, L.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Bulky ligands protect molecular ruby from oxygen quenching
N2 - Chromium(III) complexes can show phosphorescence from the spin-flip excited doublet states 2E/2T1 in the near-infrared with high photoluminescence quantum yields and extremely long lifetimes in the absence of dioxygen. The prototype molecular ruby, [Cr(ddpd)2]3+ (ddpd = N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine), has a photoluminescence quantum yield and a luminescence lifetime of 13.7% and 1.1 ms in deaerated acetonitrile, respectively. However, its luminescence is strongly quenched by 3O2 via an efficient Dexter-type energy transfer process. To enable luminescence applications of molecular rubies in solution under aerobic conditions, we explored the potential of sterically demanding ddpd ligands to shield the chromium(III) center from O2 using steady state and time-resolved photoluminescence spectroscopy. The structures of the novel complexes with sterically demanding ligands were investigated by single crystal X-ray diffraction and quantum chemically by density functional theory calculations. The O2 sensitivity of the photoluminescence was derived from absolutely measured photoluminescence quantum yields and excited state lifetimes under inert and aerobic conditions and by Stern–Volmer analyses of these data. Optimal sterically shielded chromium(III) complexes revealed photoluminescence quantum yields of up to 5.1% and excited state lifetimes of 518 μs in air-saturated acetonitrile, underlining the large potential of this ligand design approach to broaden the applicability of highly emissive chromium(III) complexes.
KW - Fluorescence
KW - Synthesis
KW - Production
KW - Optical spectroscopy
KW - Ligand
KW - Photophysics
KW - Cr(III)
KW - Mechanism
KW - NIR
KW - Sensor
KW - Oxygen
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570807
DO - https://doi.org/10.1039/d2dt02950b
VL - 51
IS - 46
SP - 17664
EP - 17670
PB - The Royal Society of Chemistry
CY - Berlin
AN - OPUS4-57080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Lisec, Jan
A1 - Koch, Matthias
T1 - Changes in Black Truffle (Tuber melanosporum) Aroma during Storage under Different Conditions
N2 - The enticing aroma of truffles is a key factor for their culinary value. Although all truffle species tend to be pricy, the most intensely aromatic species are the most sought after. Research into the aroma of truffles encompasses various disciplines including chemistry, biology, and sensory science. This study focusses on the chemical composition of the aroma of black truffles (Tuber melanosporum) and the changes occurring under different storage conditions. For this, truffle samples were stored under different treatments, at different temperatures, and measured over a total storage time of 12 days. Measurements of the truffle aroma profiles were taken with SPME/GC–MS at regular intervals. To handle the ample data collected, a systematic approach utilizing multivariate data analysis techniques was taken. This approach led to a vast amount of data which we made publicly available for future exploration. Results reveal the complexity of aroma changes, with 695 compounds identified, highlighting the need for a comprehensive understanding. Principal component analyses offer initial insights into truffle composition, while individual compounds may serve as markers for age (formic acid, 1-methylpropyl ester), freshness (2-Methyl-1-propanal; 1-(methylthio)-propane), freezing (tetrahydrofuran), salt treatment (1-chloropentane), or heat exposure (4-hydroxy-3-methyl-2-butanone). This research suggests that heat treatment or salt contact significantly affects truffle aroma, while freezing and cutting have less pronounced effects in comparison. The enrichment of compounds showing significant changes during storage was investigated with a metabolomic pathway analysis. The involvement of some of the enriched compounds on the pyruvate/glycolysis and sulfur pathways was shown.
KW - Mass Spectrometry
KW - Metabolomics
KW - Tuber melanosporum
KW - Truffle Aroma
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601731
DO - https://doi.org/10.3390/jof10050354
VL - 10
IS - 5
SP - 1
EP - 22
PB - MDPI
AN - OPUS4-60173
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, Lena
A1 - Tavernaro, Isabella
A1 - Eckert, J. G.
A1 - Lutowski, Marc
A1 - Geißler, Daniel
A1 - Hertwig, Andreas
A1 - Hidde, Gundula
A1 - Bigall, N. C.
A1 - Resch-Genger, Ute
T1 - Influence of nanoparticle encapsulation and encoding on the surface chemistry of polymer carrier beads
N2 - Surface-functionalized polymer beads encoded with molecular luminophores and nanocrystalline emitters such as semiconductor nanocrystals, often referred to as quantum dots (QDs), or magnetic nanoparticles are broadly used in the life sciences as reporters and carrier beads. Many of these applications require a profound knowledge of the chemical nature and total number of their surface functional groups (FGs), that control bead charge, colloidal stability, hydrophobicity, and the interaction with the environment and biological systems. For bioanalytical applications, also the number of groups accessible for the subsequent functionalization with, e.g., biomolecules or targeting ligands is relevant. In this study, we explore the influence of QD encoding on the amount of carboxylic acid (COOH) surface FGs of 2 μm polystyrene microparticles (PSMPs). This is done for frequently employed oleic acid and oleylamine stabilized, luminescent core/shell CdSe QDs and two commonly used encoding procedures. This included QD addition during bead formation by a thermally induced polymerization reaction and a post synthetic swelling procedure. The accessible number of COOH groups on the surface of QD-encoded and pristine beads was quantified by two colorimetric assays, utilizing differently sized reporters and electrostatic and covalent interactions. The results were compared to the total number of FGs obtained by a conductometric titration and Fourier transform infrared spectroscopy (FTIR). In addition, a comparison of the impact of QD and dye encoding on the bead surface chemistry was performed. Our results demonstrate the influence of QD encoding and the QD-encoding strategy on the number of surface FG that is ascribed to an interaction of the QDs with the carboxylic acid groups on the bead surface. These findings are of considerable relevance for applications of nanoparticle-encoded beads and safe-by-design concepts for nanomaterials.
KW - Optical spectroscopy
KW - Particle
KW - Optical assay
KW - IR spectroscopy
KW - Fluorescence
KW - Quantum yield
KW - Quality assurance
KW - Nano
KW - Synthesis
KW - Surface chemistry
KW - Quantification
KW - Method
KW - Conductometry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581502
DO - https://doi.org/10.1038/s41598-023-38518-7
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 15
PB - Springer Nature
CY - London
AN - OPUS4-58150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Resch-Genger, Ute
T1 - The 2023 Nobel Prize in Chemistry: Quantum dots
N2 - The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery.
KW - Quantum dots
KW - Semiconductor nanocrystals
KW - Luminescence
KW - Quantitative spectroscopy
KW - Quantum yield
KW - Advanced nanomaterials
KW - Quality assurance
KW - Energy transfer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597843
DO - https://doi.org/10.1007/s00216-024-05225-9
VL - 2024
SP - 1
EP - 11
PB - Springer
CY - Cham
AN - OPUS4-59784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohammad, W.
A1 - Wegner, Karl David
A1 - Comby-Zerbino, C.
A1 - Trouillet, V.
A1 - Ogayer, M. P.
A1 - Coll, J.-L.
A1 - Marin, R.
A1 - Jaque Garcia, D.
A1 - Resch-Genger, Ute
A1 - Antoine, R.
A1 - Le Guevel, X.
T1 - Enhanced brightness of ultra-small gold nanoparticles in the second biological window through thiol ligand shell control
N2 - Gold-based nanoparticles below 2 nm in size are promising as luminescent probes for in vivo bioimaging, owing to their brightness and rapid renal clearance. However, their use as contrast agents in the near-infrared II (NIR-II, 1000–1700 nm) range remains challenging due to their low photoluminescence (PL) quantum yield. To address this, PL enhancement can be achieved by either rigidifying the ligand-shell structure or increasing the size of the ligand shell. In this study, we synthesized ultra-small gold nanoparticles stabilized by co-ligands, namely monothiol and short dithiol molecules. By precisely controlling the amount of reducing agent used during particle preparation, we successfully modulated the physicochemical properties of the co-ligand shell, including its size, composition, and structure. Consequently, we achieved a remarkable 60-fold increase in the absorption cross-section at 990 nm while maintaining the small size of the 1.5-nm metal core. The analytical and optical characterization of our thiol-capped gold nanoparticles indicates that the ligand shell size is governed by the quantity of the reducing agent, which, in turn, impacts the balance between radiative and non-radiative processes, thereby influencing the PL quantum yield.
KW - Gold nanocluster
KW - NIR-II fluorescence
KW - SWIR
KW - Nanomaterial design
KW - Calibrated fluorescence measurements
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588117
DO - https://doi.org/10.1039/D3TC03021K
SN - 2050-7526
VL - 11
IS - 42
SP - 14714
EP - 14724
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fiedler, Saskia
A1 - Frenzel, Florian
A1 - Würth, Christian
A1 - Tavernaro, Isabella
A1 - Grüne, M.
A1 - Schweizer, S.
A1 - Engel, A.
A1 - Resch-Genger, Ute
T1 - Interlaboratory Comparison on Absolute Photoluminescence Quantum Yield Measurements of Solid Light Converting Phosphors with Three Commercial Integrating Sphere Setups
N2 - Scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders are increasingly relevant for fundamental research and industry. Examples are luminescent nano- and microparticles and phosphors of different compositions in various matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter to characterize the performance of these materials is the photoluminescence/fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. To identify and quantify the sources of uncertainty of absolute measurements of Φf of scattering samples, the first interlaboratory comparison (ILC) of three laboratories from academia and industry was performed by following identical measurement protocols. Thereby, two types ofcommercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring the Φf of transparent and scattering dye solutions and solid phosphors, namely, YAG:Ce optoceramics of varying surface roughness, used as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While the Φf values of the liquid samples matched between instruments, Φf measurements of the optoceramics with different blanks revealed substantial differences. The ILC results underline the importance of the measurement geometry, sample position, and blank for reliable Φf data of scattering the YAG:Ce optoceramics, with the blank’s optical properties accounting for uncertainties exceeding 20%.
KW - Nano
KW - Fluorescence
KW - Reference material
KW - Luminescence
KW - Quantitative spectroscopy
KW - Particle
KW - Quantum yield
KW - Quality assurance
KW - Phosphor
KW - Converter material
KW - Lifetime
KW - Interlaboratory comparison
KW - Method
KW - Uncertainty
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600945
DO - https://doi.org/10.1021/acs.analchem.4c00372
SN - 0003-2700
SP - 6730
EP - 6737
PB - ACS Publications
AN - OPUS4-60094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Cui
A1 - Ebel, Kenny
A1 - Heinze, Katja
A1 - Resch-Genger, Ute
A1 - Bald, Ilko
T1 - Quantum Yield of DNA Strand Breaks under Photoexcitation of a Molecular Ruby
N2 - Photodynamic therapy (PDT) used for treating cancer relies on the generation of highly reactive oxygen species, for example, singlet oxygen 1O2, by light-induced excitation of a photosensitizer (PS) in the presence of molecular oxygen, inducing DNA damage in close proximity of the PS. Although many precious metal complexes have been explored as PS for PDT and received clinical approval, only recently, the potential of photoactive complexes of nonnoble metals as PS has been discovered. Using the DNA origami technology that can absolutely quantify DNA strand break cross sections, we assessed the potential of the luminescent transition metal complex [Cr(ddpd)2]3+ (ddpd=N,N’-dimethyl-N,N’-dipyridine-2-ylpyridine-2,6-diamine) to damage DNA in an air-saturated aqueous environment upon UV/Vis illumination. The quantum yield for strand breakage, that is, the ratio of DNA strand breaks to the number of absorbed photons, was determined to 1–4%, indicating efficient transformation of photons into DNA strand breaks by [Cr(ddpd)2]3+.
KW - Fluorescence
KW - Synthesis
KW - Production
KW - Optical spectroscopy
KW - Ligand
KW - Photophysics
KW - Cr(III)
KW - Mechanism
KW - NIR
KW - PDT
KW - Singlet oxygen
KW - DNA
KW - Origami
KW - Quantum yield
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573631
DO - https://doi.org/10.1002/chem.202203719
SP - 1
EP - 7
AN - OPUS4-57363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - López-Iglesias, C.
A1 - Markovina, A.
A1 - Nirmalananthan-Budau, N.
A1 - Resch-Genger, Ute
A1 - Klinger, D.
T1 - Optically monitoring the microenvironment of a hydrophobic cargo in amphiphilic nanogels: influence of network composition on loading and release
N2 - Amphiphilic nanogels (ANGs) are promising carriers for hydrophobic cargos such as drugs, dyes, and catalysts.
Loading content and release kinetics of these compounds are controlled by type and number of hydrophobic groups in the amphiphilic copolymer network. Thus, understanding the interactions between cargo and colloidal carrier is mandatory for a tailor-made and cargo-specific ANG design. To systematically explore the influence of the network composition on these interactions, we prepared a set of ANGs of different amphiphilicity and loaded these ANGs with varying concentrations of the solvatochromic dye Nile Red (NR). Here, NR acts as a hydrophobic model cargo to optically probe the polarity of its microenvironment. Analysis of the NR emission spectra as well as measurements of the fluorescence quantum yields and decay kinetics revealed a decrease in the polarity of the NR microenvironment with increasing hydrophobicity of the hydrophobic groups in the ANG network and dye–dye interactions at higher loading concentrations. At low NR concentrations, the hydrophobic cargo NR is encapsulated in the hydrophobic domains. Increasing NR concentrations resulted in probe molecules located in a more hydrophilic environment, i.e., at the nanodomain border, and favored dye–dye interactions and NR aggregation.
These results correlate well with release experiments, indicating first NR release from more hydrophilic network locations. Overall, our findings demonstrate the importance to understand carrier–drug interactions for efficient loading and controlled release profiles in amphiphilic nanogels.
KW - Particle
KW - Energy transfer
KW - Limit of detection
KW - Polymer
KW - Luminescence
KW - Quantitative spectroscopy
KW - Nano
KW - Quantum yield
KW - Lifetime
KW - Quality assurance
KW - Dye
KW - Probe
KW - Sensor
KW - Nile Red
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601603
DO - https://doi.org/10.1039/d4nr00051j
SN - 2040-3364
IS - 16
SP - 9525
EP - 9535
PB - The Royal Society of Chemistry
AN - OPUS4-60160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Sander, P. C.
A1 - Andresen, Elina
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Expanding the Toolbox of Simple, Cost-Efficient, and Automatable Methods for Quantifying Surface Functional Groups on Nanoparticles� Potentiometric Titration
N2 - Measuring surface functional groups (FGs) on nanomaterials (NMs) is essential for designing dispersible and stable NMs with tailored and predictable functionality. FG screening and quantification also plays a critical role for subsequent processing steps, NM long-term stability, quality control of NM production, and risk assessment studies and enables the implementation of sustainable and safe(r)-by-design concepts. This calls for simple and cost-efficient methods for broadly utilized FGs that can be ideally automated to speed up FG screening, monitoring, and quantification. To expand our NM surface analysis toolbox, focusing on simple methods and broadly available, cost-efficient instrumentation, we explored a NM-adapted pH titration method with potentiometric and optical readout for measuring the total number of (de)protonable FGs on representatively chosen commercial and custom-made aminated silica nanoparticles (SiO2 NPs). The accuracy and robustness of our stepwise optimized workflows was assessed by several operators in two laboratories and method validation was done by cross-comparison with two analytical methods relying on different signal generation principles. This included traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA), providing the amounts of amino silanes released by particle dissolution and the total mass of the surface coatings. A comparison of the potentiometric titration results with the reporter-specific amounts of surface amino FGs determined with the previously automated fluorescamine (Fluram) assay highlights the importance of determining both quantities for surface-functionalized NMs. In the future, combined NM surface analysis with optical assays and pH titration will simplify quality control of NM production processes and stability studies and can yield large data sets for NM grouping that facilitates further developments in regulation and standardization.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - Fluorescamine
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642371
DO - https://doi.org/10.1021/acsmeasuresciau.5c00062
SN - 2694-250X
SP - 1
EP - 13
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-64237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herter, Sven-Oliver
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Semisynthesis of Stable Isotope-Labeled Ergot Alkaloids for HPLC-MS/MS Analysis
N2 - Ergot alkaloids (EAs) are prevalent food contaminants affecting cereals, such as rye, wheat, and barley worldwide. To ensure EU safety standards, the six most common EAs: ergometrine, ergotamine, ergosine, ergocornine, ergocristine, and ergocryptine, and their epimers, are quantified using HPLC-MS/MS, as described in the European Standard Method EN 17425:2021. However, this can be challenging and time-consuming in food matrices without appropriate internal standards and highlights the need for more robust and precise analytical tools to support their monitoring. The development of isotope-labeled EAs directly addresses this gap, offering improved accuracy and leading to more consistency across laboratories and consequently to more consumer safety. Therefore, we developed a semisynthetic approach, building upon our previous work where native ergotamine was N6-demethylated to norergotamine and subsequently remethylated using iodomethane (13CD3-I). Herein, we are now able to present the successful synthesis of all of the isotopically labeled priority EAs. These isotope-labeled standards were tested against their native counterparts using HPLC coupled with HR-MS/MS. The chromatographic and mass spectrometric properties of the unlabeled and isotopically labeled EAs match exactly, confirming their successful synthesis and structure. These standards can now be utilized to enhance the accuracy and reliability of EA quantification in food and feed.
KW - Reference Material
KW - HPLC-MS/MS
KW - Mycotoxins
KW - Ergot Alkaloids
KW - Stable Isotope Dilution Analysis
KW - Semisynthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639692
DO - https://doi.org/10.1021/acs.jafc.5c03345
SN - 0021-8561
VL - 73
IS - 29
SP - 18412
EP - 18419
PB - American Chemical Society (ACS)
AN - OPUS4-63969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stiegler, L. M. S.
A1 - Wegner, Karl David
A1 - Weigert, Florian
A1 - Peukert, W.
A1 - Resch-Genger, Ute
A1 - Walter, J.
T1 - Analysis of Giant-Shell CdSe/CdS Quantum Dots via Analytical Ultracentrifugation Combined with Spectrally Resolved Photoluminescence
N2 - Knowledge of the structure–property relationships of functional nanomaterials, including, for example, their size- and composition-dependent photoluminescence (PL) and particle-to-particle variations, is crucial for their design and reproducibility. Herein, the Angstrom-resolution capability of an analytical ultracentrifuge combined with an in-line multiwavelength emission detection system (MWE-AUC) for measuring the sedimentation coefficient-resolved spectrally corrected PL spectra of dispersed nanoparticles is demonstrated. The capabilities of this technique are shown for giant-shell CdSe/CdS quantum dots (g-QDs) with a PL quantum yield (PL QY) close to unity capped with oleic acid and oleylamine ligands. The MWE-AUC PL measurements are calibrated and validated with certified fluorescence standards. The spectrally corrected and size-dependent PL spectra of the g-QDs derived from a single MWE-AUC experiment are then analyzed and compared with the results of single-particle spectroscopic studies, yielding the PL spectra, decay kinetics, and blinking behavior of individual g-QDs. This study underlines the vast potential of MWE-AUC with in-line optical detection for the characterization of advanced nanomaterials with a complex structure.
KW - Quantum dots
KW - Analytical ultracentrifugation
KW - Photoluminescence
KW - Advanced nanomaterial characterization
KW - Calibrated fluorescence measurements
KW - Reference materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624357
DO - https://doi.org/10.1002/smtd.202401700
SN - 2366-9608
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-62435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Extending certified spectral fluorescence standards for the calibration and performance validation of fluorescence instruments to the NIR—closing the gap from 750 to 940 nm with two novel NIR dyes
N2 - Fluorescence techniques such as fluorescence spectroscopy, microfluorometry, and fluorescence microscopy, providing spectral, intensity, polarization, and lifetime information, are amongst the most broadly utilized analytical methods in the life and materials sciences. However, the measured fluorescence data contain sample- and instrument-specific contributions, which hamper their comparability across instruments and laboratories. Comparable, instrument-independent fluorescence data require the determination of the fluorescence instrument’s wavelength-dependent spectral responsivity, also termed emission correction curve, for the same instrument settings as those used for the fluorescence measurements as a prerequisite for the subsequent correction of the measured instrument-specific data. Such a spectral correction is essential for the performance comparison of different fluorescent labels and reporters, quantitative fluorescence measurements, the determination of the fluorescence quantum yield, and the spectroscopic measure for the fluorescence efficiency of a fluorophore. Simple-to-use tools for obtaining emission correction curves are chromophore-based reference materials (RMs), referred to as fluorescence standards, with precisely known, preferably certified instrument-independent fluorescence spectra. However, for the increasingly used near-infrared (NIR) wavelength region >700 nm, at present, no spectral fluorescence standards are available. To close this gap, we developed two novel spectral fluorescence standards, BAM F007 and BAM-F009, with broad emission bands from about 580 to 940 nm in ethanolic solution. These liquid fluorescence standards currently under certification, which will be released in 2025, will expand the wavelength range of the already available certified Calibration Kit BAM F001b-F005b from about 300–730 to 940 nm. In this research article, we will detail the criteria utilized for dye and matrix selection and the homogeneity and stability tests accompanying dye certification as well as the calculation of the wavelength-dependent uncertainty budgets of the emission spectra BAM F007 and BAM-F009, determined with the traceably calibrated BAM reference spectrofluorometer. These fluorescence standards can provide the basis for comparable fluorescence measurements in the ultraviolet, visible, and NIR for the fluorescence community.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626317
DO - https://doi.org/10.1007/s00216-024-05723-w
SN - 1618-2650
SP - 1
EP - 15
PB - Springer
AN - OPUS4-62631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Deumer, J.
A1 - Andresen, Elina
A1 - Gollwitzer, C.
A1 - Schürmann, R.
A1 - Resch-Genger, Ute
T1 - Adding More Shape to Nanoscale Reference Materials-LiYF4:Yb,Tm Bipyramids as Standards for Sizing Methods and Particle Number Concentration
N2 - The increasing industrial use of nanomaterials calls for the reliable characterization of their physicochemical key properties like size, size distribution, shape, and surface chemistry, and test and reference materials (RMs) with sizes and shapes, closely matching real-world nonspheric nano-objects. An efficient strategy to minimize efforts in producing nanoscale RMs (nanoRMs) for establishing, validating, and standardizing methods for characterizing nanomaterials are multimethod nanoRMs.
Ideal candidates are lanthanide-based, multicolor luminescent, and chemically inert nanoparticles (NPs) like upconversion nanoparticles (UCNPs), which can be prepared in different sizes, shapes, and chemical composition with various surface coatings. This makes UCNPs interesting candidates as standards not only for sizing methods, but also for element-analytical methods like laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS), quantitative bioimaging methods like X-ray fluorescence computed tomography (XFCT), and luminescence methods and correlative measurements.
Here, we explore the potential of two monodisperse LiYF4:Yb,Tm bipyramids with peak-to-peak distances of (43 ± 2) nm and (29 ± 2) nm as size standards for small-angle X-ray scattering (SAXS) and tools for establishing and validating the sophisticated simulations required for the analysis of SAXS data derived from dispersions of nonspheric nano-objects. These SAXS studies are supplemented by two-dimensional (2D)-transmission electron microscopy measurements of the UCNP bipyramids. Additionally, the particle number concentration of cyclohexane dispersions of these UCNP bipyramids is determined by absolute SAXS measurements, complemented by gravimetry, thermogravimetric analysis (TGA), and inductively coupled plasma optical emission spectrometry (ICP-OES). This approach enables traceable particle number concentration measurements of ligand-capped nonspheric particles with unknown chemical composition.
KW - Fluorescence
KW - Upconversion nanoparticles
KW - SAXS
KW - Particle number concentration
KW - Reference material
KW - Traceability
KW - Quality assurance
KW - Quantum yield
KW - Spectroscopy
KW - Synthesis
KW - Quantification
KW - NanoRM
KW - Nano
KW - Particle
KW - Bipyramid
KW - Reference data
KW - Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617940
DO - https://doi.org/10.1021/acs.analchem.4c03641
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-61794
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knoche, Lisa
A1 - Lisec, Jan
A1 - Schwerdtle, T.
A1 - Koch, Matthias
T1 - LC-HRMS-Based Identification of Transformation Products of the Drug Salinomycin Generated by Electrochemistry and Liver Microsome
N2 - The drug salinomycin (SAL) is a polyether antibiotic and used in veterinary Medicine as coccidiostat and growth promoter. Recently, SAL was suggested as a potential anticancer drug.
However, transformation products (TPs) resulting from metabolic and environmental degradation of SAL are incompletely known and structural information is missing. In this study, we therefore systematically investigated the formation and identification of SAL derived TPs using electrochemistry (EC) in an electrochemical reactor and rat and human liver microsome incubation (RLM and HLM) as TP generating methods. Liquid chromatography (LC) coupled to high-resolution mass spectrometry (HRMS) was applied to determine accurate masses in a suspected target analysis to identify TPs and to deduce occurring modification reactions of derived TPs. A total of 14 new, structurally different TPs were found (two EC-TPs, five RLM-TPs, and 11 HLM-TPs). The main modification reactions are decarbonylation for EC-TPs and oxidation (hydroxylation) for RLM/HLM-TPs. Of particular interest are potassium-based TPs identified after liver microsome incubation because these might have been overlooked or declared as oxidated sodium adducts in previous, non-HRMS-based studies due to the small mass difference between K and O + Na of 21 mDa. The MS fragmentation pattern of TPs was used to predict the position of identified modifications in the SAL molecule. The obtained knowledge regarding transformation reactions and novel TPs of SAL will contribute to elucidate SAL-metabolites with regards to structural prediction.
KW - Salinomycin
KW - Ionophore antibiotics
KW - Transformation product
KW - Electrochemistry
KW - Rat/human liver microsomes
KW - HRMS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542543
DO - https://doi.org/10.3390/antibiotics11020155
SN - 2079-6382
VL - 11
IS - 2
SP - 155
PB - MDPI
CY - Basel
AN - OPUS4-54254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kage, Daniel
A1 - Hoffmann, Katrin
A1 - Wittkamp, M.
A1 - Ameskamp, J.
A1 - Göhde, W.
A1 - Resch-Genger, Ute
T1 - Luminescence lifetime encoding in time-domain flow cytometry
N2 - Time-resolved flow cytometry represents an alternative to commonly applied spectral or intensity multiplexing in bioanalytics. At present, the vast majority of the reports on this topic focuses on phase-domain techniques and specific applications. In this report, we present a flow cytometry platform with time-resolved detection based on a compact setup and straightforward time-Domain measurements utilizing lifetime-encoded beads with lifetimes in the nanosecond range. We provide general assessment of time-domain flow cytometry and discuss the concept of this platform to address achievable resolution limits, data analysis, and requirements on suitable encoding dyes. Experimental data are complemented by numerical calculations on photon count numbers and impact of noise and measurement time on the obtained lifetime values.
KW - Flow cytometry
KW - Fluorescence
KW - Life sciences
KW - Lifetime encoding
KW - Polymer particles
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465765
DO - https://doi.org/10.1038/s41598-018-35137-5
SN - 2045-2322
VL - 8
IS - 1
SP - 16715, 1
EP - 11
PB - Nature
CY - London
AN - OPUS4-46576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahiboz, D.
A1 - Andresen, Elina
A1 - Manley, P.
A1 - Resch-Genger, Ute
A1 - Würth, Christian
A1 - Becker, C.
T1 - Metasurface-Enhanced Photon Upconversion upon 1550 nm Excitation
N2 - Photon upconversion upon 1550 nm excitation is of high relevance for applications in the third biological excitation window, for photovoltaics beyond current limitations, and enables appealing options in the field of glass Fiber telecommunications. Trivalent doped erbium ions (Er3+) are the material of choice for 1550 nm excited upconversion, however, they suffer from a low absorption cross-section and a low brightness. Therefore, the ability of Silicon metasurfaces to provide greatly enhanced electrical near-fields is employed to enable efficient photon upconversion even at low external Illumination conditions. Hexagonally shaped β-NaYF4:Er3+ nanoparticles are placed on large-area silicon metasurfaces designed to convert near-infrared (1550 nm) to visible light. More than 2400-fold enhanced photon upconversion luminescence is achieved by using this metasurface instead of a planar substrate.
With the aid of optical simulations based on the finite-element method, this result is attributed to the coupling of the excitation source with metasurface resonances at appropriate incident angles. Analysis of the excitation power density dependence of upconversion luminescence and red-to-green-emission ratios enables the estimation of nanoscale near-field enhancement on the metasurface. The findings permit the significant reduction of required external excitation intensities for photon upconversion of 1550 nm light, opening perspectives in biophotonics, telecommunication, and photovoltaics.
KW - Nano
KW - Nanomaterial
KW - Upconversion nanoparticle
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - Excitation power density
KW - Single particle
KW - Brightness
KW - NIR
KW - Mechanism
KW - Single enhancement
KW - SWIR
KW - Method
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537193
DO - https://doi.org/10.1002/adom.202101285.
SN - 2195-1071
VL - 9
IS - 24
SP - 2101285
PB - Wiley-VCH-GmbH
AN - OPUS4-53719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Carl, F.
A1 - Grauel, Bettina
A1 - Pons, Monica
A1 - Würth, Christian
A1 - Haase, M.
T1 - LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with luminescence decay times similar to YLF laser crystals and the upconversion quantum yield of the Yb,Er doped nanocrystals
N2 - We developed a procedure to prepare luminescent LiYF4:Yb/LiYF4 and LiYF4:Yb,Er/LiYF4 core/shell nanocrystals with a size of approximately 40 nm revealing luminescence decay times of the dopant ions that approach those of high-quality laser crystals of LiYF4:Yb (Yb:YLF) and LiYF4:Yb,Er (Yb,Er:YLF) with identical doping concentrations. As the luminescence decay times of Yb3+ and Er3+ are known to be very sensitive to the presence of quenchers, the long decay times of the core/shell nanocrystals indicate a very low number of defects in the core particles and at the core/shell interfaces. This improvement in the performance was achieved by introducing two important modifications in the commonly used oleic acid based synthesis. First, the shell was prepared via anewly developed method characterized by a very low nucleation rate for particles of pure LiYF4 shell material. Second, anhydrous acetates were used as precursors and additional drying steps were applied to reduce the incorporation of OH− in the crystal lattice, known to quench the emission of Yb3+ ions. Excitation power density (P)-dependent absolute measurements of the upconversion luminescence quantum yield (Φ,UC) of LiYF4:Yb,Er/LiYF4 core/shell particles reveal a maximum value of 1.25% at P of 180 W·cm−2.
Although lower than the values reported for NaYF4:18%Yb,2%Er core/shell nanocrystals with comparable sizes, these Φ, UC values are the highest reported so far for LiYF4:18%Yb,2%Er/LiYF4 nanocrystals without additional dopants. Further improvements May nevertheless be possible by optimizing the dopant concentrations in the LiYF4 nanocrystals.
KW - Nano
KW - Crystal
KW - Quantum yield
KW - LiYF4
KW - Synthesis
KW - Lifetime
KW - Fluorescence
KW - NIR
KW - Photoluminescence
KW - Lanthanide
KW - Upconversion nanoparticle
KW - Nanomaterial
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515395
DO - https://doi.org/10.1007/s12274-020-3116-y
SN - 1998-0124
VL - 14
IS - 3
SP - 797
EP - 806
PB - Springer
AN - OPUS4-51539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Grauel, Bettina
A1 - Pons, Monika
A1 - Frenzel, Florian
A1 - Rissiek, P.
A1 - Rücker, Kerstin
A1 - Haase, Markus
A1 - Resch-Genger, Ute
T1 - Yb- and Er concentration dependence of the upconversion luminescence of highly doped NaYF4:Yb,Er/NaYF4:Lu core/shell nanocrystals prepared by a water-free synthesis
N2 - High sensitizer and activator concentrations have been increasingly examined to improve the performance of multi-color emissive upconversion (UC) nanocrystals (UCNC) like NaYF4:Yb,Er and first strategies were reported to reduce concentration quenching in highly doped UCNC. UC luminescence (UCL) is, however, controlled not only by dopant concentration, yet by an interplay of different parameters including size, crystal and shell quality, and excitation power density (P). Thus, identifying optimum dopant concentrations requires systematic studies of UCNC designed to minimize additional quenching pathways and quantitative spectroscopy. Here, we quantify the dopant concentration dependence of the UCL quantum yield (ΦUC) of solid
NaYF4:Yb,Er/NaYF4:Lu upconversion core/shell nanocrystals of varying Yb3+ and Er3+ concentrations (Yb3+ series: 20%‒98% Yb3+; 2% Er3+; Er3+ series: 60% Yb3+; 2%‒40% Er3+). To circumvent other luminescence quenching processes, an elaborate synthesis yielding OH-free UCNC with record ΦUC of ~9% and ~25 nm core particles with a thick surface shell were used. High Yb3+ concentrations barely reduce ΦUC from ~9% (20% Yb3+) to ~7% (98% Yb3+) for an Er3+ concentration of 2%, thereby allowing to strongly increase the particle absorption cross section and UCNC brightness. Although an increased Er3+ concentration reduces ΦUC from ~7% (2% Er3+) to 1% (40%) for 60% Yb3+. Nevertheless, at very high P (> 1 MW/cm2) used for microscopic studies, highly Er3+-doped UCNC display a high brightness because of reduced saturation. These findings underline the importance of synthesis control and will pave the road to many fundamental studies of UC materials.
KW - Upconverion
KW - Nanoparticle
KW - Lanthanides
KW - Quantum yield
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551346
DO - https://doi.org/10.1007/s12274-022-4570-5
SP - 1
EP - 8
PB - Springer
AN - OPUS4-55134
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuner, Maximilian
A1 - Lisec, Jan
A1 - Picher, Marie-Idrissa
A1 - Rigo, Massimo
A1 - Konetzki, Jörg
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Development and Application of Isotope Labelled Internal Standards in a Sum Parameter Method for Ergot Alkaloid Screening of Food
N2 - Ergot alkaloids are a group of toxic compounds, formed by fungi on infested grasses. In 2022, the European Commission set into effect maximum levels for the sum of the twelve major ergot alkaloids in multiple foods. To facilitate the laborious and costly individual quantification of the twelve major ergot alkaloids by HPLC–MS/MS or -FLD, we recently reported a sum parameter method (SPM) for ergot alkaloid quantification. Here, derivatization to lysergic acid hydrazide—a derivative of the mutual ergoline backbone in all ergot alkaloids—allowed simplified determination of all ergot alkaloids in flour via HPLC-FLD. For the measurement of more complex matrices like processed foods, we now developed a MS/MS-based SPM. Two internal standards (IS), isotopically labelled at different positions of the molecule, were synthesized and employed in the MS/MS-measurements. Method performance using either the 13CD3-labelled or the 15N2-labelled IS was evaluated on naturally contaminated rye and wheat flour samples as well as on processed food matrices. Employing the 13CD3-labelled IS leads to lower variances and better consistency with the reference data (obtained by the FLD-based SPM) in flour samples compared to the 15N2-labelled IS. The novel method significantly improves the measurement of ergot alkaloids in complex food matrices, due to their increased selectivity and thus lower interferences. Furthermore, the application of isotope labelled IS obviates the need for time-consuming steps like the determination of recovery rate based, matrix specific correction factors as described in the MS/MS-based European standard method for ergot alkaloid quantification (EN 17425).
KW - Mycotoxins
KW - Sum Parameter Method
KW - Isotope Labelling
KW - HPLC-MS/MS
KW - Analytical Chemistry
KW - Lysergic acid hydrazide
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588582
DO - https://doi.org/10.1007/s12161-023-02553-x
SN - 1936-976X
VL - 17
IS - 1
SP - 119
EP - 128
PB - Springer
CY - New York, NY
AN - OPUS4-58858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Borzekowski, Antje
A1 - Drewitz, T.
A1 - Keller, Julia
A1 - Pfeifer, Dietmar
A1 - Kunte, Hans-Jörg
A1 - Koch, Matthias
A1 - Rohn, S.
A1 - Maul, R.
T1 - Biosynthesis and characterization of zearalenone-14-sulfate, zearalenone-14-glucoside and zearalenone-16-glucoside using common fungal strains
N2 - Zearalenone (ZEN) and its phase II sulfate and glucoside metabolites have been detected in food and feed commodities. After consumption, the conjugates can be hydrolyzed by the human intestinal microbiota leading to liberation of ZEN that implies an underestimation of the true ZEN exposure. To include ZEN conjugates in routine analysis, reliable standards are needed, which are currently not available. Thus, the aim of the present study was to develop a facilitated biosynthesis of ZEN-14-sulfate, ZEN-14-glucoside and ZEN-16-glucoside. A metabolite screening was conducted by adding ZEN to liquid fungi cultures of known ZEN conjugating Aspergillus and Rhizopus strains. Cultivation conditions and ZEN incubation time were varied. All media samples were analyzed for metabolite formation by HPLC-MS/MS. In addition, a consecutive biosynthesis was developed by using Fusarium graminearum for ZEN biosynthesis with subsequent conjugation of the toxin by utilizing Aspergillus and Rhizopus species. ZEN-14-sulfate (yield: 49%) is exclusively formed by Aspergillus oryzae. ZEN-14-glucoside (yield: 67%) and ZEN-16-glucoside (yield: 39%) are formed by Rhizopus oryzae and Rhizopus oligosporus, respectively. Purities of ≥73% ZEN-14-sulfate, ≥82% ZEN-14-glucoside and ≥50% ZEN-16-glucoside were obtained by 1H-NMR. In total, under optimized cultivation conditions, fungi can be easily utilized for a targeted and regioselective synthesis of ZEN conjugates.
KW - Mycotoxin
KW - Zearalenone
KW - Conjugate
KW - Biosynthesis
KW - Fusarium
KW - Aspergillus
KW - Rhizopus
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444246
DO - https://doi.org/10.3390/toxins10030104
SN - 2072-6651
VL - 10
IS - 3
SP - Article 104, 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-44424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kage, Daniel
A1 - Hoffmann, Katrin
A1 - Nifontova, G.
A1 - Krivenkov, V.
A1 - Sukhanova, A.
A1 - Nabiev, I.
A1 - Resch-Genger, Ute
T1 - Tempo-spectral multiplexing in flow cytometry with lifetime detection using QD-encoded polymer beads
N2 - Semiconductor quantum dots (QDs) embedded into polymer microbeads are known to be very attractive emitters for spectral multiplexing and colour encoding. Their luminescence lifetimes or decay kinetics have been, however, rarely exploited as encoding parameter, although they cover time ranges which are not easily accessible with other luminophores. We demonstrate here the potential of QDs made from II/VI semiconductors with luminescence lifetimes of several 10 ns to expand the lifetime range of organic encoding luminophores in multiplexing applications using time-resolved flow cytometry (LT-FCM). For this purpose, two different types of QD-loaded beads were prepared and characterized by photoluminescence measurements on the ensemble level and by single-particle confocal laser scanning microscopy. Subsequently, these lifetime-encoded microbeads were combined with dye-encoded microparticles in systematic studies to demonstrate the potential of these QDs to increase the number of lifetime codes for lifetime multiplexing and combined multiplexing in the time and colour domain (tempo-spectral multiplexing). These studies were done with a recently developed novel luminescence lifetime flow cytometer (LT-FCM setup) operating in the time-domain, that presents an alternative to reports on phase-sensitive lifetime detection in flow cytometry.
KW - Fluorescence life time
KW - Flow cytometry
KW - Lifetime-encoded beads
KW - Quantum dots
KW - Multiplexing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503316
DO - https://doi.org/10.1038/s41598-019-56938-2
VL - 10
IS - 1
SP - Article number: 653
PB - nature.com
AN - OPUS4-50331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keller, Julia
A1 - Hantschke, Luisa
A1 - Haase, H.
A1 - Koch, Matthias
T1 - Synthesis and Structural Identification of a Biaryl Ether-Linked Zearalenone Dimer
N2 - A new dimer of the food-relevant mycotoxin zearalenone was isolated after electrochemical and chemical oxidation. The structure was determined as a 16-O-15'-biaryl ether-linked dimer based on spectroscopic analyses (1H- and 13C-NMR, COSY, HMBC, and HSQCAD) and high-Resolution mass spectrometry analysis (Q-TOF).
KW - Mycotoxin
KW - Dimerization
KW - HRMS
KW - NMR
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464940
DO - https://doi.org/10.3390/molecules23102624
SN - 1420-3049
VL - 23
IS - 10
SP - 2624
EP - 2628
PB - MDPI
CY - Basel
AN - OPUS4-46494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krappe, Alexander R.
A1 - Mayer, Jacob C.
A1 - Zhang, Wuai
A1 - Filla, Lina M.
A1 - Ligorio, Giovanni
A1 - Hermerschmidt, Felix
A1 - Eitelhuber, Larissa S.
A1 - Güttler, Arne
A1 - Weber, Manuela
A1 - Paulus, Beate
A1 - Resch-Genger, Ute
A1 - List-Kratochvil, Emil J.W.
A1 - Eigler, Siegfried
T1 - Highly Emissive Hexa-peri-benzocoronene-fluoranthene Hybrid as Easily Processable and Stable OLED Material
N2 - We report the synthesis of a fluorescent polycyclic aromatic hydrocarbon dye with a “symmetry-broken” core, derived from the related hexa-peri-benzocoronene (HBC) core with fluoranthene subunit. The fluorophore is composed of a pure Carbon skeleton without heteroatoms and exhibits remarkable photo luminescence properties with a photoluminescence Quantum yield (PLQY) of up to 67% in toluene, exceeding that of theparent HBC by a factor of 30. The single crystal X-ray structure reveals the distorted polycyclic aromatic hydrocarbon structure, which is responsible for the optoelectronic properties, as supported by density functional theory calculations. We show that the new fluorescent dye can be readily used for the fabrication of organic light-emitting diodes (OLED) without extensive optimization, whereby solubility in a variety of solvents and successful film formation are decisive.
KW - Quantum Yield
KW - OLED
KW - Fluorescence
KW - Synthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631298
DO - https://doi.org/10.1002/chem.202500742
SN - 1521-3765
SP - 1
EP - 7
PB - John Wiley & Sons, Inc
AN - OPUS4-63129
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Solid-State Emissive Aroyl-S,N-Ketene Acetals with Tunable
N2 - N-Benzyl aroyl-S,N-ketene acetals can be readily synthesized by condensation of aroyl chlorides and N-Benzyl 2-methyl benzothiazolium salts in good to excellent yields, yielding a library of 35 chromophores with bright solid-state emission and aggregation-induced emission characteristics.
Varying the substituent from electron-donating to electronwithdrawing enables the tuning of the solid-state emission Color from deep blue to red.
KW - Nano
KW - Nanoparticle
KW - Photoluminescence
KW - Fluorescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - dye
KW - Enhancement
KW - Particle
KW - Polarity
KW - AIE
KW - Aggregation
KW - Aggregation-induced emission
KW - Solid state emission
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509072
DO - https://doi.org/10.1002/anie.201916396
VL - 59
IS - 25
SP - 10037
EP - 10041
PB - Wiley Online Libary
AN - OPUS4-50907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Behnke, Thomas
A1 - Gienger, J.
A1 - Resch-Genger, Ute
T1 - Efficiency scale for scatteringluminescent particles linkedto fundamental and measurablespectroscopic properties
N2 - Comparing the performance of molecular and nanoscale luminophores and luminescent microand nanoparticles and estimating achievable signal amplitudes and limits of detection requires a standardizable intensity scale. This initiated the development of the relative MESF (number of molecules of equivalent soluble fluorochromes) and ERF (equivalent reference fluorophores) scales for flow cytometry and fluorescence microscopy. Both intensity scales rely on fluorescence intensity values assigned to fluorescent calibration beads by an intensity comparison to spectrally closely matching fluorophore solutions of known concentration using a spectrofluorometer. Alternatively, the luminophore or bead brightness (B) can be determined that equals the product of the absorption cross section (σa) at the excitation wavelength (σa(λex)) and the photoluminescence quantum yield (Φpl).
Thereby, an absolute scale based on fundamental and measurable spectroscopic properties can be realized which is independent of particle size, material, and luminophore staining or labeling density and considers the sensitivity of the optical properties of luminophores to their environment. Aiming for establishing such a brightness scale for light-scattering dispersions of luminescent particles with sizes exceeding a few ten nanometers, we demonstrate how the brightness of quasi-monodisperse 25 nm, 100 nm, and 1 μm sized polystyrene particles (PSP), loaded with two different dyes in varying concentrations, can be obtained with a single custom-designed integrating sphere setup that enables the absolute determination of Φpl and transmittance and diffuse reflectance measurements. The resulting Φpl, σa(λex), imaginary parts of the refractive index, and calculated B values of these samples are given in dependence of the number of incorporated dye molecule per particle. Finally, a unitless luminescence efficiency (LE) is defined allowing for the direct comparison of luminescence efficiencies of particles with different sizes.
KW - Brightness
KW - Quantum yield
KW - Cross section
KW - Lluminescence
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573680
DO - https://doi.org/10.1038/s41598-023-32933-6
VL - 13
IS - 1
SP - 14
PB - Nature
AN - OPUS4-57368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - May, L.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Hoffmann, Katrin
A1 - Resch-Genger, Ute
A1 - Müller, T. J. J.
T1 - Communication of Bichromophore Emission upon Aggregation – Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines
N2 - Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution patterntunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.
KW - Dye
KW - Fluorescence
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531123
DO - https://doi.org/10.1002/chem.202102052
VL - 27
IS - 53
SP - 13426
EP - 13434
PB - Wiley-VCH
AN - OPUS4-53112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, F.
A1 - Fiedler, S.
A1 - Bardan, A.
A1 - Güttler, Arne
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Influence of Measurement Geometry and Blank on Absolute Measurements of Photoluminescence Quantum Yields of Scattering Luminescent Films
N2 - For a series of 500 μm-thick polyurethane films containing different concentrations of luminescent and scattering YAG:Ce microparticles, we systematically explored and quantified pitfalls of absolute measurements of photoluminescence quantum yields (Φf) for often employed integrating sphere (IS) geometries, where the sample is placed either on a sample holder at the bottom of the IS surface or mounted in the IS center. Thereby, the influence of detection and illumination geometry and sample position was examined using blanks with various scattering properties for measuring the number of photons absorbed by the sample. Our results reveal that (i) setup configurations where the scattering sample is mounted in the IS center and (ii) transparent blanks can introduce systematic errors in absolute Φf measurements.
For strongly scattering, luminescent samples, this can result in either an under- or overestimation of the absorbed photon flux and hence an under- or overestimation of Φf. The size of these uncertainties depends on the scattering properties of the sample and instrument parameters, such as sample position, IS size, wavelength-dependent reflectivity of the IS surface coating, and port configuration. For accurate and reliable absolute Φf measurements, we recommend (i) a blank with scattering properties closely matching those of the sample to realize similar distributions of the diffusely scattered excitation photons within the IS, and (ii) a sufficiently high sample absorption at the excitation wavelength. For IS setups with center-mounted samples, measurement geometries should be utilized that prevent the loss of excitation photons by reflections from the sample out of the IS.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Quantum yield
KW - Characterization
KW - Silica
KW - Scattering
KW - Uncertainty
KW - Film
KW - Pphosphor
KW - YAG:Ce
KW - LED
KW - Converter material
KW - Solid material
KW - Polymer
KW - Composite material
KW - Advanced material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638304
DO - https://doi.org/10.1021/acs.analchem.4c06726
SN - 1520-6882
SP - 1
EP - 8
PB - ACS Publications
AN - OPUS4-63830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuner, Maximilian
A1 - Lisec, Jan
A1 - Mauch, Tatjana
A1 - Konetzki, J.
A1 - Haase, H.
A1 - Koch, Matthias
T1 - Quantification of Ergot Alkaloids via Lysergic Acid Hydrazide—Development and Comparison of a Sum Parameter Screening Method
N2 - Ergot alkaloids are a group of mycotoxins occurring in products derived from various grasses (e.g., rye) and have been regulated in the EU recently. The new maximum levels refer to the sum of the six most common ergot alkaloids in their two stereoisomeric forms in different food matrices. Typically, these twelve compounds are individually quantified via HPLC-MS/MS or -FLD and subsequently summed up to evaluate food safety in a time-consuming process. Since all these structures share the same ergoline backbone, we developed a novel sum parameter method (SPM) targeting all ergot alkaloids simultaneously via lysergic acid hydrazide. After extraction and clean-up, in analogy to the current European standard method EN 17425 (ESM) for ergot alkaloid quantitation, the samples were derivatized by an optimized hydrazinolysis protocol, which allowed quantitative conversion after 20 min at 100 °C. The new SPM was evaluated against another established HPLC-FLD-based method (LFGB) and the HPLC-MS/MS-based ESM using six naturally contaminated rye and wheat matrix reference materials. While the SPM provided comparable values to the ESM, LFGB showed deviating results. Determined recovery rates, limits of detection and quantification of all three employed methods confirm that the new SPM is a promising alternative to the classical approaches for ergot alkaloid screening in food.
KW - Ergot alkaloids
KW - Sum Parameter
KW - Mycotoxins
KW - Derivatization
KW - Hydrazinolysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573968
DO - https://doi.org/10.3390/molecules28093701
SN - 0015-2684
VL - 28
IS - 9
SP - 3701
PB - MDPI
CY - Basel
AN - OPUS4-57396
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, A.
A1 - Lischeid, G.
A1 - Koch, Matthias
A1 - Lentzsch, P.
A1 - Sommerfeld, Thomas
A1 - Müller, M.H.
T1 - Co-Cultivation of Fusarium, Alternaria, and Pseudomonas on Wheat-Ears Affects Microbial Growth and Mycotoxin Production
N2 - Mycotoxigenic fungal pathogens Fusarium and Alternaria are a leading cause of loss in cereal production. On wheat-ears, they are confronted by bacterial antagonists such as pseudomonads.
Studies on these groups’ interactions often neglect the infection process’s temporal aspects and the associated priority effects. In the present study, the focus was on how the first colonizer affects the subsequent ones. In a climate chamber experiment, wheat-ears were successively inoculated with two different strains (Alternaria enuissima At625, Fusarium graminearum Fg23, or Pseudomonas simiae Ps9).
Over three weeks, microbial abundances and mycotoxin concentrations were analyzed and visualized via Self Organizing Maps with Sammon Mapping (SOM-SM). All three strains revealed different characteristics and strategies to deal with co-inoculation: Fg23, as the first colonizer, suppressed the establishment of At625 and Ps9. Nevertheless, primary inoculation of At625 reduced all of the Fusarium toxins and stopped Ps9 from establishing. Ps9 showed priority effects in delaying and blocking the production of the fungal mycotoxins. The SOM-SM analysis visualized the competitive strengths: Fg23 ranked first, At625 second, Ps9 third. Our findings of species-specific priority effects in a natural environment and the role of the mycotoxins involved are relevant for developing biocontrol strategies.
KW - Antagonists
KW - Microbe interactions
KW - Mycotoxins
KW - Priority effect
KW - SOM-SM
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521554
DO - https://doi.org/10.3390/microorganisms9020443
VL - 9
IS - 2
SP - 443
PB - MDPI
AN - OPUS4-52155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, R.
A1 - Teich, W.
A1 - Frenzel, Florian
A1 - Hoffmann, Katrin
A1 - Radke, J.
A1 - Rösler, J.
A1 - Faust, K.
A1 - Blank, A.
A1 - Brandenburg, S.
A1 - Misch, M.
A1 - Vajkoczy, P.
A1 - Onken, J. S.
A1 - Resch-Genger, Ute
T1 - Optical characterization of sodium fluorescein in vitro and ex vivo
N2 - Objective: The utilization of fluorescein-guided biopsies and resection has been recently discussed as a suitable strategy to improve and expedite operative techniques for the resection of central nervous system (CNS) tumors. However, little is known about the optical properties of sodium fluorescein (NaFl) in human tumor tissue and their potential impact on ex vivo analyses involving fluorescence-based methods.
Methods: Tumor tissue was obtained from a study cohort of an observational study on the utilization of fluorescein-guided biopsy and resection (n=5). The optical properties of fluorescein-stained tissue were compared to the optical features of the dye in vitro and in control samples consisting of tumor tissue of high-grade glioma patients (n=3) without intravenous (i.v.) application of NaFl. The dye-exposed tumor tissues were used for optical measurements to confirm the detectability of NaFl emission ex vivo. The tissue samples were fixed in 4%PFA, immersed in 30% sucrose, embedded in Tissue-Tek OCT compound, and cut to 10 mm cryosections. Spatially resolved emission spectra from tumor samples were recorded on representative slides with a Confocal Laser Scanning Microscope FV1000 (Olympus GmbH, Hamburg, Germany) upon excitation with lexc = 488 nm.
Results: Optical measurements of fluorescein in 0.9% sodium chloride (NaCl) under in vitro conditions showed an absorption maximum of lmax abs = 479 nm as detected with spectrophotometer Specord 200 and an emission peak at lmax em = 538 nm recorded with the emCCD detection system of a custom-made microscope-based single particle setup using a 500 nm long-pass filter. Further measurements revealed pH- and concentration-dependent emission spectra of NaFl. Under ex vivo conditions, confocal laser scanning microscopy of fluorescein tumor samples revealed a slight bathochromic shift and a broadening of the emission band.
Conclusion: Tumor uptake of NaFl leads to changes in the optical properties – a bathochromic shift and broadening of the emission band – possibly caused by the dye’s high pH sensitivity and concentration-dependent reabsorption acting as an innerfilter of the dye’s emission, particularly in the short wavelength region of the Emission spectrum where absorption and fluorescence overlap. Understanding the ex vivo optical properties of fluorescein is crucial for testing and validating its further applicability as an optical probe for intravital microscopy, immunofluorescence localization studies, and flow cytometry analysis.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Fluorescein
KW - PH
KW - Imaging
KW - Tissue
KW - Cancer
KW - Medical diagnostics
KW - Tumor
KW - In vivo
KW - Ex vivo
KW - Quantum yield
KW - Dye
KW - Quality assurance
KW - Microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527843
DO - https://doi.org/10.3389/fonc.2021.654300
SN - 2234-943X
VL - 11
SP - 1
EP - 8
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-52784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nelson, G.
A1 - Boehm, U.
A1 - Bagley, S.
A1 - Bajcsy, P.
A1 - Bischof, J.
A1 - Brown, C. M.
A1 - Dauphin, A.
A1 - Dobbie, I. M.
A1 - Eriksson, J. E.
A1 - Faklaris, O.
A1 - Fernandez-Rodriguez, J.
A1 - Ferrand, A.
A1 - Gelman, L,
A1 - Gheisari, A.
A1 - Hartmann, H.
A1 - Kukat, C.
A1 - Laude, A.
A1 - Mitkovski, M.
A1 - Munck, S.
A1 - North, A. J.
A1 - Rasse, T.
A1 - Resch-Genger, Ute
A1 - Schuetz, L. C.
A1 - Seitz, A.
A1 - Strambio-De-Castillia, C.
A1 - Swedlow, J. R.
A1 - Alexopoulos, I.
A1 - Aumayr, K.
A1 - Avilov, S.
A1 - Bakker, G.-J.
A1 - Bammann, R. R.
A1 - Bassi, A.
A1 - Beckert, H.
A1 - Beer, S.
A1 - Belyaev, Y.
A1 - Bierwagen, J.
A1 - Birngruber, K. A.
A1 - Bosch, M.
A1 - Breitlow, J.
A1 - Cameron, L. A.
A1 - Chalfoun, J.
A1 - Chambers, J. J.
A1 - Chen, C.-L.
A1 - Conde-Sousa, E.
A1 - Corbett, A. D.
A1 - Cordelieres, F. P.
A1 - Del Nery, E.
A1 - Dietzel, R.
A1 - Eismann, F.
A1 - Fazeli, E.
A1 - Felscher, A.
A1 - Fried, H.
A1 - Gaudreault, N.
A1 - Goh, W. I.
A1 - Guilbert, T.
A1 - Hadleigh, R.
A1 - Hemmerich, P.
A1 - Holst, G. A.
A1 - Itano, M. S.
A1 - Jaffe, C. B.
A1 - Jambor, H. K.
A1 - Jarvis, S. C.
A1 - Keppler, A.
A1 - Kirchenbuechler, D.
A1 - Kirchner, M.
A1 - Kobayashi, N.
A1 - Krens, G.
A1 - Kunis, S.
A1 - Lacoste, J.
A1 - Marcello, M.
A1 - Martins, G. G.
A1 - Metcalf, D. J.
A1 - Mitchell, C. A.
A1 - Moore, J.
A1 - Mueller, T.
A1 - Nelson, M. S.
A1 - Ogg, S.
A1 - Onami, S.
A1 - Palmer, A. L.
A1 - Paul-Gilloteaux, P.
A1 - Pimentel, J. A.
A1 - Plantard, L.
A1 - Podder, S.
A1 - Rexhepaj, E.
A1 - Royon, A.
A1 - Saari, M. A.
A1 - Schapman, D.
A1 - Schoonderwoert, V.
A1 - Schroth-Diez, B.
A1 - Schwartz, S.
A1 - Shaw, M.
A1 - Spitaler, M.
A1 - Stoeckl, M. T.
A1 - Sudar, D.
A1 - Teillon, J.
A1 - Terjung, S.
A1 - Thuenauer, R.
A1 - Wilms, C. D.
A1 - Wright, G. D.
A1 - Nitschke, R.
T1 - QUAREP-LiMi: A community-driven initiative to establish guidelines for quality assessment and reproducibility for instruments and images in light microscopy
N2 - A modern day light microscope has evolved from a tool devoted to making primarily empirical observations to what is now a sophisticated, quantitative device that is an integral part of both physical and life science research. Nowadays, microscopes are found in nearly every experimental laboratory. However, despite their prevalent use in capturing and quantifying scientific phenomena, neither a thorough understanding of the principles underlying quantitative imaging techniques nor appropriate knowledge of how to calibrate, operate and maintain microscopes can be taken for granted. This is clearly demonstrated by the well-documented and widespread difficulties that are routinely encountered in evaluating acquired data and reproducing scientific experiments. Indeed, studies have shown that more than 70% of researchers have tried and failed to repeat another scientist’s experiments, while more than half have even failed to reproduce their own experiments1. One factor behind the reproducibility crisis of experiments published in scientific journals is the frequent underreporting of imaging methods caused by a lack of awareness and/or a lack of knowledge of the applied technique2,3. Whereas quality control procedures for some methods used in biomedical research, such as genomics (e.g., DNA sequencing, RNA-seq) or cytometry, have been introduced (e.g. ENCODE4), this issue has not been tackled for optical microscopy instrumentation and images. Although many calibration standards and protocols have been published, there is a lack of awareness and agreement on common Standards and guidelines for quality assessment and reproducibility5.
In April 2020, the QUality Assessment and REProducibility for instruments and images in Light Microscopy (QUAREP-LiMi) initiative6 was formed. This initiative comprises imaging scientists from academia and industry who share a common interest in achieving a better understanding of the performance and limitations of microscopes and improved quality control (QC) in light microscopy. The ultimate goal of the QUAREP-LiMi initiative is to establish a set of common QC standards, guidelines, metadata models7,8, and tools9,10, including detailed protocols, with the ultimate aim of improving reproducible advances in scientific research.
This White Paper 1) summarizes the major obstacles identified in the field that motivated the launch of the QUAREP-LiMi initiative; 2) identifies the urgent need to address these obstacles in a grassroots manner, through a community of Stakeholders including, researchers, imaging scientists11, bioimage analysts, bioimage informatics developers, corporate partners, Funding agencies, standards organizations, scientific publishers, and observers of such; 3) outlines the current actions of the QUAREPLiMi initiative, and 4) proposes future steps that can be taken to improve the dissemination and acceptance of the proposed guidelines to manage QC.
To summarize, the principal goal of the QUAREP-LiMi initiative is to improve the overall quality and reproducibility of light microscope image data by introducing broadly accepted standard practices and accurately captured image data metrics.
KW - Fluorescence
KW - Microscopy
KW - Quality assurance
KW - Comparability
KW - Imaging
KW - Standards
KW - Reference materials
KW - Reliability
KW - Data
KW - Reference data
KW - Biology
KW - Medicine
KW - Life science
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530629
DO - https://doi.org/10.1111/jmi.13041
SN - 1365-2818
VL - 284
IS - 1
SP - 56
EP - 73
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-53062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Juliane
A1 - Recknagel, Sebastian
A1 - Sassenroth, Diana
A1 - Mauch, Tatjana
A1 - Buttler, Sabine
A1 - Sommerfeld, Thomas
A1 - Penk, Sibylle
A1 - Koch, Matthias
T1 - Development and certification of a reference material for zearalenone in maize germ oil
N2 - Zearalenone (ZEN), an estrogenic mycotoxin produced by several species of Fusarium fungi, is a common contaminant of cereal-based food worldwide. Due to frequent occurrences associated with high levels of ZEN, maize oil is a particular source of exposure. Although a European maximumlevel for ZEN in maize oil exists according to Commission Regulation (EC) No. 1126/2007 along with a newly developed international standard method for analysis, certified reference materials (CRM) are still not available. To overcome this lack, the first CRM for the determination of ZEN in contaminated maize germ oil (ERM®-BC715) was developed in the frame of a European Reference Materials (ERM®) project according to the requirements of ISO Guide 35. The whole process of CRM development including preparation, homogeneity and stability studies, and value assignment is presented. The assignment of the certified mass fraction was based upon an in-house study using high-performance liquid chromatography isotope dilution tandem mass spectrometry. Simultaneously, to support the in-house certification study, an interlaboratory comparison study was conducted with 13 expert laboratories using different analytical methods. The certified mass fraction and expanded uncertainty (k=2) of ERM®-BC715 (362± 22) μg kg−1 ZEN are traceable to the SI. This reference material is intended for analytical quality control and contributes to the improvement of consumer protection and food safety.
KW - Fusarium mycotoxin
KW - Vegetable edible oil
KW - Food analysis
KW - European Reference Material
KW - Quality assurance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531831
DO - https://doi.org/10.1007/s00216-021-03532-z
SN - 1618-2642
SN - 1618-2650
VL - 413
IS - 21
SP - 5483
EP - 5491
PB - Springer
CY - Berlin
AN - OPUS4-53183
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biesen, L.
A1 - Krenzer, J.
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
A1 - Müller, Th. J. J.
T1 - Asymmetrically bridged aroyl-S,N-ketene acetalbased multichromophores with aggregationinduced tunable emission
N2 - Asymmetrically bridged aroyl-S,N-ketene acetals and aroyl-S,N-ketene acetal multichromophores can be readily synthesized in consecutive three-, four-, or five-component syntheses in good to excellent yields by several successive Suzuki-couplings of aroyl-S,N-ketene acetals and bis(boronic)acid esters. Different aroyl-S,N-ketene acetals as well as linker molecules yield a library of 23 multichromophores with substitution and linker pattern-tunable emission properties. This allows control of different communication pathways between the chromophores and of aggregation-induced emission (AIE) and energy transfer (ET) properties, providing elaborate aggregation-based fluorescence switches.
KW - Dye
KW - Aggregation
KW - Aggregation induced emission
KW - Signal enhancement
KW - Energy transfer
KW - Switch
KW - Sensor
KW - Quantum yield
KW - Lifetime
KW - Photophysics
KW - Sythesis
KW - Nanaoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550719
DO - https://doi.org/10.1039/d2sc00415a
VL - 13
SP - 5374
EP - 5381
PB - Royal Society of Chemistry
AN - OPUS4-55071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keller, Julia
A1 - Borzekowski, Antje
A1 - Haase, H.
A1 - Menzel, R.
A1 - Rueß, L.
A1 - Koch, Matthias
T1 - Toxicity assay for citrinin, zearalenone and zearalenone-14-sulfate using the nematode Caenorhabditis elegans as model organism
N2 - To keep pace with the rising number of detected mycotoxins, there is a growing need for fast and reliable toxicity tests to assess the potential threat to food safety. Toxicity tests with the bacterial-feeding nematode Caenorhabditis elegans as model organism are well established. In this study the C. elegans wildtype strain N2 (var. Bristol) was used to investigate the toxic effects of the food-relevant mycotoxins citrinin (CIT) and zearalenone-14-sulfate (ZEA-14-S) and zearalenone (ZEA) on different life cycle parameters including reproduction, thermal and oxidative stress resistance and lifespan. The metabolization of the mycotoxins by the nematodes in vivo was investigated using HPLC-MS/MS. ZEA was metabolized in vivo to the reduced isomers α-zearalenol (α-ZEL) and β-ZEL. ZEA 14-S was reduced to α-/β-ZEL 14-sulfate and CIT was metabolized to mono-hydroxylated CIT. All mycotoxins tested led to a significant decrease in the number of nematode offspring produced. ZEA and CIT displayed negative effects on stress tolerance levels and for CIT an additional shortening of the mean lifespan was observed. In the case of ZEA-14-S, however, the mean lifespan was prolonged. The presented study shows the applicability of C. elegans for toxicity testing of emerging food mycotoxins for the purpose of assigning potential health threats.
KW - Mycotoxins
KW - Metabolization
KW - Toxicity testing
KW - Biotests
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-455772
DO - https://doi.org/10.3390/toxins10070284
VL - 10
IS - 7
SP - 284, 1
EP - 12
PB - MDPI
AN - OPUS4-45577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keller, Julia
A1 - Moldenhauer, Daniel
A1 - Byrne, L.
A1 - Haase, H.
A1 - Resch-Genger, Ute
A1 - Koch, Matthias
T1 - Complexes of the mycotoxins citrinin and ochratoxin A with aluminum ions and their spectroscopic properties
N2 - The sensitive detection of the mycotoxin citrinin (CIT) utilizing ist fluorescence requires approaches to enhance the emission. In this respect, we studied the complexation of CIT and ochratoxin A (OTA) with Al3+ in methanol using absorption and fluorescence spectroscopy. In this context, an isocratic high performance liquid chromatography (HPLC) method using a polymer column and a fluorescence detector was also developed that enables the separation of the metal ion complexes from the free ligands and non-complexed Al3+. CIT and OTA showed distinct changes in their absorption and fluorescence properties upon Al3+-coordination, and the fluorescence of CIT was considerably enhanced. Analysis of the photometrically assessed titration of CIT and OTA with Al3+ using the Job plot method revealed 1:2 and 1:1 stoichiometries for the Al3+ complexes of CIT (Al:CIT) and OTA (Al:OTA), respectively. In the case of CIT, only one -diketone moiety participates in Al3+ coordination. These findings can be elegantly exploited for signal amplification and provide the base to reduce the limit of detection for CIT quantification by about an order of magnitude, as revealed by HPLC measurements using a fluorescence detector.
KW - Complexation
KW - Aluminum
KW - Fluorescence
KW - Job plot
KW - HPLC-DAD/FLD
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470502
DO - https://doi.org/10.3390/toxins10120538
SN - 2072-6651
VL - 10
IS - 12
SP - 538, 1
EP - 8
PB - MDPI
CY - Basel
AN - OPUS4-47050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moll, J.
A1 - Wang, Cui
A1 - Päpcke, A.
A1 - Förster, C.
A1 - Resch-Genger, Ute
A1 - Lochbrunner, S.
A1 - Heinze, K.
T1 - Green Light Activation of Push-Pull Ruthenium(II) Complexes
N2 - Synthesis, characterization, electrochemistry, and photophysics of novel homo- and heteroleptic ruthenium(II) complexes [Ru(cpmp)2] 2+ (22+) and [Ru(cpmp)(ddpd)]2+ (32+) bearing the tridentate ligands 6,2’’-carboxypyridyl-2,2’-methylamine-pyridylpyridine (cpmp) and N,N’-dimethyl-N,N’-dipyridin-2-ylpyridine-2,6-diamine (ddpd) are reported. The complexes possess one (32+) or two (22+) electron-deficient dipyridyl ketone fragments as electron accepting sites enabling intraligand charge transfer (ILCT), ligand-toligand charge transfer (LL’CT) and low-energy metal-to-ligand charge transfer (MLCT) absorptions. The latter peak around 544 nm (green light). 22+ shows 3MLCT phosphorescence in the red to near-infrared spectral region at room temperature in deaerated acetonitrile solution with an emission quantum yield of 1.3 % and a 3MLCT lifetime of 477 ns, while 3
2+ is much less luminescent. This different behaviour is ascribed to the energy gap law and the shape of the parasitic excited 3MC state potential energy surface. This study highlights the importance of the excited state energies and geometries for the actual excited state dynamics. Aromatic and aliphatic amines reductively quench the excited state of 22+ paving the way to photocatalytic applications using low-energy green light as exemplified with the green-light sensitized thiol-ene click reaction.
KW - Green light excitation
KW - Ruthenium(II) complexes
KW - Phosphorescence
KW - MLCT
KW - Photoinduced electron transfer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506759
DO - https://doi.org/10.1002/chem.202000871
SP - 1
EP - 13
PB - Wiley-VCH Verlag
AN - OPUS4-50675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Soares, J. X.
A1 - Wegner, Karl David
A1 - Ribeiro, D. S. M.
A1 - Melo, A.
A1 - Häusler, I.
A1 - Santos, J. L. M.
A1 - Resch-Genger, Ute
T1 - Rationally designed synthesis of bright AgInS2/ZnS quantum dots with emission control
N2 - In the blossoming field of Cd-free semiconductor quantum dots (QDs), ternary I–III–VI QDs have received increasing attention due to the ease of the environmentally friendly synthesis of high-quality materials in water, their high photoluminescence (PL) Quantum yields (QYs) in the red and near infrared (NIR) region, and their inherently low toxicity. Moreover, their oxygen-insensitive long PL lifetimes of up to several hundreds of nanoseconds close a gap for applications exploiting the compound-specific parameter PL lifetime. To overcome the lack of reproducible synthetic methodologies and to enable a design-based control of their PL properties, we assessed and modelled the synthesis of high-quality MPA-capped AgInS2/ZnS (AIS/ZnS) QDs. Systematically refined Parameters included reaction time, temperature, Ag:In ratio, S:In ratio, Zn:In ratio, MPA:In ratio, and pH using a design-of-experiment approach.
Guidance for the optimization was provided by mathematical models developed for the application-relevant PL parameters, maximum PL wavelength, QY, and PL lifetime as well as the elemental composition in terms of Ag:In:Zn ratio. With these experimental data-based models, MPA:In and Ag:In ratios and pH values were identified as the most important synthesis parameters for PL Control and an insight into the connection of these parameters could be gained. Subsequently, the experimental conditions to synthetize QDs with tunable emission and high QY were predicted. The excellent agreement between the predicted and experimentally found PL features confirmed the reliability of our methodology for the rational design of high quality AIS/ZnS QDs with defined PL features.
This approach can be straightforwardly extended to other ternary and quaternary QDs and to doped QDs.
KW - Modelling
KW - Nanoparticle
KW - AIS
KW - Semiconductor quantum dot
KW - Design of experiment
KW - Photoluminescence
KW - Quantum yield
KW - Surface chemistry
KW - Synthesis
KW - Lifetime
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510075
DO - https://doi.org/10.1007/s12274-020-2876-8
VL - 13
IS - 9
SP - 2438
EP - 2450
PB - Springer
AN - OPUS4-51007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalot, G.
A1 - Godard, A.
A1 - Busser, B.
A1 - Pliquett, J.
A1 - Broekgaarden, M.
A1 - Motto-Ros, V.
A1 - Wegner, Karl David
A1 - Resch-Genger, Ute
A1 - Köster, U.
A1 - Denat, F.
A1 - Coll, J.-L.
A1 - Bodio, E.
A1 - Goze, C.
A1 - Sancey, L.
T1 - Aza-BODIPY: A New Vector for Enhanced Theranostic Boron Neutron Capture Therapy Applications
N2 - Boron neutron capture therapy (BNCT) is a radiotherapeutic modality based on the nuclear capture of slow neutrons by stable 10B atoms followed by charged particle Emission that inducing extensive damage on a very localized level (<10 um). To be effcient, a suffcient amount of 10B should accumulate in the tumor area while being almost cleared from the normal surroundings. A water-soluble aza-boron-dipyrromethene dyes (BODIPY) fluorophore was reported to strongly accumulate in the tumor area with high and BNCT compatible Tumor/Healthy Tissue ratios.
The clinically used 10B-BSH (sodium borocaptate) was coupled to the water-soluble aza-BODIPY platform for enhanced 10B-BSH tumor vectorization. We demonstrated a strong uptake of the compound in tumor cells and determined its biodistribution in mice-bearing tumors. A model of chorioallantoic membrane-bearing glioblastoma xenograft was developed to evidence the BNCT potential of such compound, by subjecting it to slow neutrons. We demonstrated the Tumor accumulation of the compound in real-time using optical imaging and ex vivo using elemental imaging based on laser-induced breakdown spectroscopy. The tumor growth was significantly reduced as compared to BNCT with 10B-BSH. Altogether, the fluorescent aza-BODIPY/10B-BSH compound is able to vectorize and image the 10B-BSH in the tumor area, increasing its theranostic potential for effcient approach of BNCT.
KW - Aza-BODIPY
KW - SWIR
KW - NIR-I
KW - Theranostic
KW - Boron compound
KW - Optical imaging
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512280
DO - https://doi.org/10.3390/cells9091953
VL - 9
IS - 9
SP - 1953
PB - MDPI
AN - OPUS4-51228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kage, Daniel
A1 - Hoffmann, Katrin
A1 - Borcherding, H.
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Lifetime encoding in flow cytometry for bead‑based sensing of biomolecular interaction
N2 - To demonstrate the potential of time-resolved flow cytometry (FCM) for bioanalysis, clinical diagnostics, and optically encoded bead-based assays, we performed a proof-of-principle study to detect biomolecular interactions utilizing fluorescence lifetime (LT)-encoded micron-sized polymer beads bearing target-specific bioligands and a recently developed prototype lifetime flow cytometer (LT-FCM setup). This instrument is equipped with a single excitation light source and different fluorescence detectors, one operated in the photon-counting mode for time-resolved measurements of fluorescence decays and three detectors for conventional intensity measurements in different spectral windows. First, discrimination of bead-bound biomolecules was demonstrated in the time domain exemplarily for two targets, Streptavidin (SAv) and the tumor marker human chorionic gonadotropin (HCG). In a second step, the determination of biomolecule concentration levels was addressed representatively for the inflammation-related biomarker tumor necrosis factor (TNF-α) utilizing fluorescence intensity measurements in a second channel of the LT-FCM instrument. Our results underline the applicability of LT-FCM in the time domain for measurements of biomolecular interactions in suspension assays. In the future, the combination of spectral and LT encoding and multiplexing and the expansion of the time scale from the lower nanosecond range to the longer nanosecond and the microsecond region is expected to provide many distinguishable codes. This enables an increasing degree of multiplexing which could be attractive for high throughput screening applications.
KW - Fluorescence
KW - Sensor
KW - Assay
KW - Protein
KW - Multiplexing
KW - Flow cytometry
KW - Barcoding
KW - Lifetime
KW - Dye
KW - Bead
KW - Bead-based assay
KW - Method
KW - Quantification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516007
DO - https://doi.org/10.1038/s41598-020-76150-x
VL - 10
IS - 1
SP - 19477
PB - Nature
AN - OPUS4-51600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Katrin
A1 - Nirmalananthan-Budau, Nithiya
A1 - Resch-Genger, Ute
T1 - Fluorescence calibration standards made from broadband emitters encapsulated in polymer beads for fluorescence microscopy and flow cytometry
N2 - We present here the design and characterization of a set of spectral calibration beads. These calibration beads are intended for the determination and regular control of the spectral characteristics of fluorescence microscopes and other fluorescence measuring devices for the readout of bead-based assays. This set consists of micrometer-sized polymer beads loaded with dyes from the liquid Calibration Kit Spectral Fluorescence Standards developed and certified by BAM for the wavelength-dependent Determination of the spectral responsivity of fluorescencemeasuring devices like spectrofluorometers. To cover the wavelength Region from 400 to 800 nm, two new near-infrared emissive dyes were included, which were spectroscopically characterized in solution and encapsulated in the beads. The resulting set of beads presents the first step towards a new platform of spectral calibration beads for the determination of the spectral characteristics of fluorescence instruments like fluorescence microscopes, FCM setups, and microtiter plate readers, thereby meeting the increasing demand for reliable and comparable fluorescence data especially in strongly regulated areas, e.g., medical diagnostics. This will eventually provide the basis for standardized calibration procedures for imaging systems as an alternative to microchannel slides containing dye solutions previously reported by us.
KW - Fluorescence standard
KW - Fluorescence
KW - Dye
KW - Microscopy
KW - Bead
KW - Particle
KW - NIR
KW - calibration
KW - Quality assurance
KW - Traceability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508117
DO - https://doi.org/10.1007/s00216-020-02664-y
SN - 1618-2642
VL - 412
IS - 24
SP - 6499
EP - 6507
PB - Springer
AN - OPUS4-50811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rietsch, P.
A1 - Sobottka, S.
A1 - Hoffmann, K.
A1 - Popov, A. A.
A1 - Hildebrandt, P.
A1 - Sarkar, B.
A1 - Resch-Genger, Ute
A1 - Eigler, S.
T1 - Between Aromatic and Quinoid Structure: A Symmetrical UV to Vis/NIR Benzothiadiazole Redox Switch
N2 - Reversibly switching the light absorption of organic molecules by redox processes is of interest for applications in sensors, light harvesting, smart materials, and medical diagnostics. This work presents a symmetrical benzothiadiazole (BTD) derivative with a high fluorescence quantum yield in solution and in the crystalline state and shows by spectroelectrochemical analysis that reversible switching of UV absorption in the neutral state, to broadband Vis/NIR absorption in the 1st oxidized state, to sharp band Vis absorption in the 2nd oxidized state, is possible.
For the one-electron oxidized species, formation of a delocalized radical is confirmed by electron paramagnetic resonance spectroelectrochemistry. Furthermore, our results reveal an increasing quinoidal distortion upon the 1st and 2nd oxidation, which can be used as the leitmotif for the development of BTD based redox switches.
KW - Dye
KW - Electrochemistry
KW - Switch
KW - Redox
KW - Sensor
KW - Photophysics
KW - Quantum yield
KW - photoluminescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517222
DO - https://doi.org/10.1002/chem.202004009
VL - 26
IS - 72
SP - 17361
EP - 17365
PB - Wiley-VCH GmbH
AN - OPUS4-51722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Fürstenwerth, Paul Christian
A1 - Witte, J. F.
A1 - Resch-Genger, Ute
T1 - Synthesis and spectroscopic characterization of a fluorescent phenanthrene-rhodamine dyad for ratiometric measurements of acid pH values
N2 - We present the rational design, synthesis and spectroscopic characterization of a novel dual excitation, three color emitting, pH-responsive fluorescent probe consisting of two phenanthrene and one rhodamine B units linked by click chemistry. The rhodamine moiety, excitable at λEx = 315 nm and at λEx = 560 nm in its ring-opened form, provides the pH-responsive fluorophore, while the pH-insensitive phenanthrene, excited at λEx = 315 nm, serves as inert internal reference, The presence of two phenanthrene moieties enables a blue monomer and a blueish green excimer emission at 351 nm and 500 nm, respectively. Opening of the rhodamine B spirolactam ring at an acidic pH below 5.0 (pKa = 2.59 ± 0.04) switches on its emission at 580 nm. Simultaneously, the phenanthrene excimer emission decreases caused by a change in orientation of the phenanthrene units, while the monomer emission is barely affected. This sensor design enables ratiometric measurements in the low acidic pH range utilizing the intensity ratios of the rhodamine B and phenanthrene excimer emission at 580 nm and 500 nm. Alternatively, also the intensity ratios of the rhodamine B and the phenanthrene monomer emission could be exploited or the sum of the phenanthrene monomer and excimer fluorescence. To the best of our knowledge, this is the first report of ratiometric sensing utilizing such a versatile type of tricolor emissive dyad probe bearing phenanthrene moieties and showing phenanthrene monomer and excimer emission.
KW - Fluorescence
KW - Optical probe
KW - Sensor
KW - Dye
KW - Rhodamine
KW - Synthesis
KW - Photophysics
KW - PH
KW - Quantum yield
KW - Quality assurance
KW - Mechanism
KW - Chemodosimeter
KW - Phenanthrene
KW - Ratiometric
KW - Dyad
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530554
DO - https://doi.org/10.1039/d1nj01573g
SN - 1144-0546
VL - 45
IS - 31
SP - 13755
EP - 13762
PB - Royal Society of Chemistry
AN - OPUS4-53055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Simon, Fabian
A1 - Gehrenkemper, Lennart
A1 - Tobias, Charlie
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
T1 - Quantification of the amount of surface groups of aminated silica nano- and microparticles utilizing a fluorine tag and HR-CS-GFMAS
N2 - The performance, bioavailability, and safe use of engineered nanomaterials (NMs) depends not only on properties such as size, shape, and surface area, but largely on surface chemistry. While many sizing methods have been established, there is still a lack of validated screening methods for determining NM surface functional groups (FGs). In this context, we present a fast and simple method for FG quantification using high resolution-continuum source-graphite furnace molecular absorption spectrometry (HR-CS-GFMAS) and assess its applicability for the surface analysis of representatively chosen aminated silica nanoparticles (NPs) and microparticles (MPs) in conjunction with amino FG labeling with a fluorine tag. For this proof-of-concept study, first surface amino FG screening of the silica NPs and MPs was done with a potentiometric back titration method, providing the total amount of protonatable surface FGs, and two optical assays relying on reporter dyes with sizes and spatial requirements, i.e., surface binding areas smaller or larger than that of the fluorine tag to estimate the maximum and reporter-accessible number of amino FGs. Subsequently, the surface amino FGs were labeled with the fluorine tag 4-(trifluoromethyl)benzoic acid (TFMB) and the amount of fluorine originating from the bound TFMB molecules was quantified by HR-CS-GFMAS in two common organic solvents, i.e., dimethyl sulfoxide (DMSO) or ethanol (EtOH) to assess possible interferences from organic matrices. Our study revealed limits of detection (LODs) and quantification (LOQs) for fluorine of 1.0 µg/L and 3.5 µg/L in EtOH and 1.5 µg/L and 5.0 µg/L in DMSO, respectively. Overall, a quick and simple method for analyzing surface FGs on NPs and MPs was presented utilizing broadly available fluorine tags and HR-CS-GFMAS for fluorine quantification, which can be applied, e.g., for homogeneity, stability, and aging studies of surface-modified particles. This could contribute to ease the understanding of property-safety relationships for surface-functionalized NMs.
KW - Fluorine Analysis
KW - Nano- and microparticles
KW - Surface group quantification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641965
DO - https://doi.org/10.1007/s00216-025-06107-4
SN - 1618-2642
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-64196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuner, Maximilian
A1 - Kühn, S.
A1 - Haase, H.
A1 - Meyer, Klas
A1 - Koch, Matthias
T1 - Cleaving Ergot Alkaloids by Hydrazinolysis - A Promising Approach for a Sum Parameter Screening Method
N2 - Ergot alkaloids are mycotoxins formed by fungi of the Claviceps genus, which are some of the most common contaminants of food and feed worldwide. These toxins are a structurally heterogeneous group of compounds, sharing an ergoline backbone. Six structures and their corresponding stereoisomers are typically quantified by either HPLC-FLD or HPLC-MS/MS and the values subsequently summed up to determine the total ergot alkaloid content. For the development of a screening method targeting all ergot alkaloids simultaneously, the alkaloids need to be transferred to one homogeneous structure: a lysergic acid derivative. In this study, two promising cleaving methods—acidic esterification and hydrazinolysis—are compared, using dihydroergocristine as a model compound. While the acidic esterification proved to be unsuitable, due to long reaction times and oxidation sensitivity, hydrazinolysis reached a quantitative yield in 40-60 min. Parallel workup of several samples is possible. An increasing effect on the reaction rate by the addition of ammonium iodide was demonstrated. Application of hydrazinolysis to a major ergot alkaloid mix solution showed that all ergopeptines were cleaved, but ergometrine/-inine was barely affected. Still, hydrazinolysis is a suitable tool for the development of a sum parameter screening method for ergot alkaloids in food and feed.
KW - Ergot alkaloids
KW - Sum parameter method
KW - Hydrazinolysis
KW - Esterification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527508
DO - https://doi.org/10.3390/toxins13050342
VL - 13
IS - 5
SP - 342
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52750
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wasternack, J.
A1 - Schröder, H. V.
A1 - Witte, J. F.
A1 - Ilisson, M.
A1 - Hupatz, H.
A1 - Hille, J. F.
A1 - Gaedke, M.
A1 - Valkonen, A. M.
A1 - Sobottka, S.
A1 - Krappe, A.
A1 - Schubert, M.
A1 - Paulus, B.
A1 - Rissanen, K.
A1 - Sarkar, B.
A1 - Eigler, S.
A1 - Resch-Genger, Ute
A1 - Schalley, C. A.
T1 - Switchable protection and exposure of a sensitive squaraine dye within a redox active rotaxane
N2 - In nature,molecular environments in proteins can sterically protect and stabilize reactive species such as organic radicals through non-covalent interactions.Here, wereport a near-infrared fluorescent rotaxane in which the stabilization of a chemically labile squaraine fluorophore by the coordination of a tetralactam macrocycle can be controlled chemically and electrochemically. The rotaxane can be switched between two co-conformations inwhich thewheel either stabilizes or exposes the fluorophore. Coordination by the wheel affects the squaraine’s stability across four redox states and renders the radical anion significantly more stable—by a factor of 6.7—than without protection by a mechanically bonded wheel. Furthermore, the fluorescence properties can be tuned by the redox reactions in a stepwise manner. Mechanically interlockedmolecules provide an excellent scaffold to stabilize and selectively expose reactive species in a co-conformational switching process controlled by external stimuli.
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Quantum yield
KW - Spectroscopy
KW - Photophysics
KW - Synthesis
KW - Squaraine
KW - Switch
KW - Redox-active
KW - Rotaxane
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614959
DO - https://doi.org/10.1038/s42004-024-01312-1
VL - 7
SP - 1
EP - 11
AN - OPUS4-61495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Changchao
A1 - Jin, Ling N.
A1 - Bank, Michael S.
A1 - Fan, Chunlan
A1 - Gillings, Michael R.
A1 - Zhao, Tingting
A1 - Han, Yong
A1 - Chen, Tian
A1 - Gao, Meng
A1 - Zhu, Dong
A1 - Chen, Qinglin
A1 - Zhu, Guibing
A1 - Wang, Jie
A1 - Wang, Lei
A1 - Liu, Jian
A1 - Yuan, Xianzheng
A1 - Huang, Qishen
A1 - Wang, Xiaofei
A1 - Jahnke, Annika
A1 - Brahney, Janice
A1 - Allen, Steve
A1 - Arp, Hans Peter H.
A1 - Oberbeckmann, Sonja
A1 - Bergmann, Melanie
A1 - Pointing, Stephen B.
A1 - Zhang, Daizhou
A1 - Rillig, Matthias C.
T1 - Potential planetary health impacts of the airborne plastisphere
N2 - Microplastics are a ubiquitous yet long-overlooked component of airborne particulate matter. The surface of these plastic particles provides a unique niche for microorganisms, collectively known as the plastisphere. The plastisphere in aquatic and terrestrial ecosystems harbors microbial communities with distinct compositions, structures, and functional profiles, posing potential planetary health risks. The characteristics, fate, and impacts of the microbiome associated with airborne microplastics, however, remain largely unknown. In this review, we fill the knowledge gaps by exploring how airborne microplastics serve as key habitats for microorganisms and the potential planetary health implications. We show that microplastics are expected to carry and sustain microorganisms over long distances and timescales in air, potentially dispersing pathogens, antibiotic-resistance genes, and other bioactive agents across ecosystems. These interactions may perturb ecological processes and biological health on a planetary scale. Interdisciplinary research and innovative methodologies are urgently required to better understand and mitigate the airborne plastisphere risks.
KW - Microplastics
KW - Microbiome
KW - Plastisphere
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645551
DO - https://doi.org/10.1016/j.oneear.2025.101446
SN - 2590-3322
VL - 8
IS - 10
SP - 1
EP - 17
PB - Elsevier B.V.
AN - OPUS4-64555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nagelschmidt, Sven
A1 - Herbrich, Uwe
A1 - Keller, Christian
A1 - Qiao, Linan
T1 - Re-evaluation of tensile and creep rupture data of metals using a modified Larson–Miller approach
N2 - More than 70 years ago, in 1952 Larson and Miller adapted an existing relationship whichevaluates the relative effects of time and temperature on creep rupture behavior of various alloys by using existing data and by constructing so-called master curves. Since that time, the formulated Larson–Miller relation, commonly known as Larson–Miller parameter, is a widely used time–temperature parameter for various applications, e.g. for rupture life, creep and relaxation analyses of metals and some other materials such as polymers, concrete and ceramics.Nevertheless, the physical meaning of this parameter as well as the determination of master curves are still the subject of major criticism.
In this work, both aspects are reviewed and analyzed with data originally considered in thepaper of Larson and Miller based on the following approach: (a) the parameter was modifiedregarding a reference time and a reference temperature according to the time–temperature superposition principle; (b) master curves were generated for five materials investigated originally by Larson and Miller, based on a stretched exponential function type.
It has been shown, that: (1) With normalized time and temperature, the Larson–Miller parameter corresponds to real logarithmic rupture time. (2) For the relationship between Creep rupture stress and the modified Larson–Miller parameter, the stretched exponential function is a good choice as a master function. (3) Corresponding model parameters have physical meaning and can be easily determined based on data from creep test data. The investigations provide a better understanding and applicability of Larson–Miller approach.
KW - Larson–Miller parameter
KW - Creep rupture time
KW - Time–temperature equivalence
KW - Stretched exponential function
KW - Extrapolation of short-term data
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644486
DO - https://doi.org/10.1016/j.engfracmech.2025.111582
SN - 0013-7944
VL - 329
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-64448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharek, Vera M.
A1 - Kröger, Tommy
A1 - Keil, Karin
A1 - Traub, Heike
A1 - Meermann, Björn
T1 - A new elemental analytical approach for microplastic sum parameter analysis—ETV/ICP-MS with CO2
N2 - Microplastics (MPs) are pervasive environmental pollutants and are considered one of the main challenges of our time. However, a fast and comprehensive analytical approach for MP analysis in complex matrices traceable to SI units is still lacking. In this context, we report a fast screening tool for the sum parameter analysis of MPs using electrothermal vaporization (ETV) coupled to inductively coupled plasma-mass spectrometry (ICP-MS). In our proof-of-concept study, we observed size-independent detection of MPs as peaks above the 13C+ signal background in the nano- to micrometer range without limitations regarding the polymer type. Quantification of the 13C+ MP signals was accomplished via an external gas calibration utilizing dynamic dilution of carbon dioxide with argon, yielding recovery rates of 80–96% for MP reference material (RM) of polymer types commonly found in the environment. The applicability to a soil sample was demonstrated through spiking experiments with a polyethylene (PE) MP RM in soil. The limit of detection (LOD) was estimated to be 0.13 µg C, equaling the detection of a single spherical low-density-PE particle of about 70 µm, and a limit of quantification (LOQ) of 0.42 µg C.
KW - ETV/ICP-MS
KW - Mikroplastik
KW - Summenparameter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646418
DO - https://doi.org/10.1007/s00216-025-06146-x
SN - 1618-2642
SP - 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-64641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerl, C.
A1 - Shahryari, M.
A1 - Reiter, R.
A1 - Proß, V.
A1 - Lehmann, K.
A1 - Kühl, A. A.
A1 - Becker, Dorit
A1 - Schulz, Andreas
A1 - Infante Duarte, C.
A1 - Taupitz, M.
A1 - Geisel, D.
A1 - Tzschätzsch, H.
A1 - Saatz, Jessica
A1 - Traub, Heike
A1 - Asbach, P.
T1 - Quantitative Analysis of Gadolinium Deposits in Liver Tissue of Patients After Single or Multiple Gadolinium-based Contrast Agent Application
N2 - Gadolinium-based contrast agents (GBCAs) are widely used in magnetic resonance imaging. Concerns exist regarding gadolinium deposition and its potential histopathologic tissue alterations, especially after repeated administrations of linear, less stable GBCAs. This study aimed to quantify gadolinium mass fractions in liver specimens of subjects exposed to GBCAs in correlation with histopathologic features.
In this study, mass fractions of gadolinium in human liver specimens from 25 subjects who underwent liver tumor resection surgery and had received GBCA (1 to 9 times over 4 years), were quantitatively analyzed using inductively coupled plasma–mass spectrometry (ICP-MS). Histomorphology was assessed based on the nonalcoholic fatty liver disease activity score (NAS).
Our results suggest that after intravenous administration of GBCA, a small fraction of gadolinium is retained in the liver over a time period of at least several weeks. A relationship was observed between Gadolinium retention and the number of GBCA administrations, but not with the cumulative dose and the degree of fatty liver disease.
KW - ICP-MS
KW - Contrast agent
KW - Gadolinium
KW - Liver
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646608
DO - https://doi.org/10.1097/RLI.0000000000001254
SN - 1536-0210
SP - 1
EP - 10
PB - Lippincott Williams & Wilkins
CY - Philadelphia, Pa.
AN - OPUS4-64660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano-Martín, Daniel
A1 - Tuma, Dirk
A1 - Chamorro, César R.
T1 - Evaluation of Reference Equations of State for Density Prediction in Regasified LNG Mixtures Using High-Precision Experimental Data
N2 - This study evaluates the performance of three reference equations of state (EoS), AGA8-DC92, GERG-2008, and SGERG-88, in predicting the density of regasified liquefied natural gas (RLNG) mixtures. A synthetic nine-component RLNG mixture was gravimetrically prepared. High-precision density measurements were obtained using a single-sinker magnetic suspension densimeter over a temperature range of (250 to 350) K and pressures up to 20 MPa. The experimental data were compared with EoS predictions to evaluate their accuracy. AGA8-DC92 and GERG-2008 showed excellent agreement with the experimental data, with deviations within their stated uncertainty. In contrast, SGERG-88 exhibited significantly larger deviations for this RLNG mixture, particularly at low temperatures of (250 to 260) K, where discrepancies reached up to 3 %. Even at 300 K, deviations larger than 0.4 % were observed at high pressures, within the model’s uncertainty, but notably higher than those of the other two EoSs. The analysis was extended to three conventional 11-component natural gas mixtures (labeled G420 NG, G431 NG, and G432 NG), previously studied by our group using the same methodology. While SGERG-88 showed reduced accuracy for the RLNG mixture, it performed reasonably well for these three mixtures, despite two of them have a very similar composition to the RLNG. This discrepancy is attributed to the lower CO2 and N2 content typical in RLNG mixtures, demonstrating the sensitivity of EoS performance to minor differences in composition. These findings highlight the importance of selecting appropriate EoS models for accurate density prediction in RLNG applications.
KW - Regasified LNG
KW - Equation of state
KW - Density
KW - Gravimetric preparation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646506
DO - https://doi.org/10.1007/s10765-025-03669-4
SN - 0195-928X
VL - 46
SP - 1
EP - 25
PB - Springer Science and Business Media LLC
CY - Heidelberg
AN - OPUS4-64650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baasch, Benjamin
A1 - Groos, Jörn
A1 - Heusel, Judith
A1 - Noll, Martin
T1 - Data-driven sparse coding for onboard condition monitoring of railway tracks
N2 - Continuous monitoring of the rail condition plays an important role in railway maintenance and the planning of noise- and vibration-reducing measures. Rail monitoring can be carried out efficiently using vibro-acoustic measurements with onboard sensors. However, this approach generates large amounts of acoustic and vibration data, which makes real-time transmission, processing and storage a challenge. This paper presents a sparse coding framework applied in the time–frequency domain that aims to overcome these challenges by significantly reducing the amount of data while preserving important information for rail defect detection and diagnosis. The Short-Time Fourier Transform is used as a preprocessing step to transform raw signals into a time–frequency representation, capturing the non-stationary characteristics of the signals. The spectrum at each time window is then represented by a sparse linear combination of basis spectra, which form a dictionary. Online sparse dictionary learning is used to create a data-driven, adaptive representation tailored to the frequency characteristics of vibro-acoustic signals related to rail defects. Experimental data acquired with a microphone and an accelerometer mounted on the wheelset of a tram are used to evaluate the framework. The experimental results show that the framework is able to achieve high compression rates and reduce noise. A reduction in data size of 98% was obtained without loss of relevant information. The proposed approach offers significant advantages for modern railway condition monitoring systems. It is scalable for large amounts of data, energy efficient and suitable for real-time implementation. By reducing data bottlenecks, it enables efficient track monitoring with on-board sensors. This work thus contributes to the development of intelligent and cost-effective solutions for infrastructure management.
KW - Railway
KW - Noise and vibration
KW - Condition monitoring
KW - Sparse coding
KW - Sparse dictionary learning
KW - Compressed sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645038
DO - https://doi.org/10.1016/j.ymssp.2025.113542
SN - 0888-3270
VL - 241
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-64503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wipfler, B.
A1 - Bradler, S.
A1 - Büsse, S.
A1 - Hammel, J.
A1 - Müller, Bernd R.
A1 - Pass, G.
T1 - Evolutionary morphology of the antennal heart in stick and leaf insects (Phasmatodea) and webspinners (Embioptera) (Insecta: Eukinolabia)
N2 - The morphology of the antennal hearts in the head of Phasmatodea and Embioptera was investigated with particular reference to phylogenetically relevant key taxa. The antennal circulatory organs of all examined species have the same basic construction: they consist of antennal vessels that are connected to ampullae located in the head near the antenna base. The ampullae are pulsatile due to associated muscles, but the points of attachment differ between the species studied. All examined Phasmatodea species have a Musculus (M.) interampullaris which extends between the two ampullae plus a M. ampulloaorticus that runs from the ampullae to the anterior end of the aorta; upon contraction, all these muscles dilate the lumina of both ampullae at the same time. In Embioptera, only the australembiid Metoligotoma has an M. interampullaris. All other studied webspinners instead have a M. ampullofrontalis which extends between the ampullae and the frontal region of the head capsule; these species do not have M. ampulloaorticus. Outgroup comparison indicates that an antennal heart with a M. interampullaris is the plesiomorphic character state among Embioptera and the likely ground pattern of the taxon Eukinolabia. Antennal hearts with a M. ampullofrontalis represent a derived condition that occurs among insects only in some embiopterans. These findings help to further clarify the controversially discussed internal phylogeny of webspinners by supporting the view that Australembiidae are the sister group of the remaining Embioptera.
KW - Phylogeny
KW - Polyneoptera
KW - Metoligotoma
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527795
DO - https://doi.org/10.1007/s00435-021-00526-4
SN - 1432-234X
VL - 140
IS - 3
SP - 331
EP - 340
PB - Springer
AN - OPUS4-52779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krenek, S.
A1 - Eisermann, R.
A1 - Failleau, G.
A1 - Lu, Xin
A1 - Thomas, P.
A1 - Kjeldsen, H.
A1 - Anhalt, K.
T1 - Fibre-optic thermometry to support the clean energy transition
N2 - The measurement and control of temperature plays a key role in achieving the European Green Deal targets for a low carbon energy system. Fibre-optic thermometry is an emerging technology that can improve temperature measurement in extreme environments for energy providers and industry due to its distributed sensing and immunity to electromagnetic fields. Various applications for optimisation and monitoring in the energy sector are described, covering the whole range from energy generation to transmission and consumption. However, fibre-optic thermometers have cross sensitivities to other quantities (e.g., strain and humidity) and ageing effects that need to be investigated, quantified and minimised to obtain traceable and reliable measurements. This is particularly important so that applications in critical infrastructure can benefit from future measurements that are not possible with conventional sensors. The European INFOTherm project aims to overcome the limitations that currently prevent the widespread use of fibre-optic thermometry by creating a dedicated European metrology infrastructure for research, development and calibration. First results on measurement uncertainty, improvement of measurement techniques and practical field tests are presented.
KW - Industrial processes optimisation
KW - Fibre-optic thermometry
KW - Distributed temperature sensing
KW - Traceability
KW - Thermal energy storage
KW - Electrical grid resilience
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640075
DO - https://doi.org/10.1515/teme-2025-0044
SN - 2196-7113
VL - 92
IS - 9-10
SP - 392
EP - 405
PB - De Gruyter Brill
AN - OPUS4-64007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dominguez-Bureos, Marco
A1 - Sens-Schönfelder, Christoph
A1 - Niederleithinger, Ernst
A1 - Hadziioannou, Céline
T1 - Stress- and Time-dependent Variations of Elastic Properties for Integrity Assessment in a Reinforced Concrete Test Bridge
N2 - In lab experiments, it has been observed that the stress–and time-dependent elastic properties of a complex material at a structural scale perform accordingly to its composition at a microstructural level. We seek complementary practices to the current wavefield-based non-destructive testing techniques to assess not only the integrity level of civil structures but also the microstructural elements that contribute to it. In this paper, we study the systematic evolution of elastic properties of concrete as an alternative to investigate the density of micro imperfections in an outdoor-conditioned concrete structure. We estimate 5-second relative velocity changes in four locations on a Test bridge subjected to the action of vertical impulsive sources, at different prestressing levels (dynamic effects at different static conditions). We describe the structure’s stress- and time-dependent elastic response by means of acoustoelastic effect and Slow-dynamic processes, respectively. We also estimate the conventional ultrasound pulse velocity and perform a cooperative integrity analysis of the structure using the three elastic phenomena. Our findings reveal: 1) The presence of soft microstructures and their orientation’s influence on the acoustoelastic effect and Slow-dynamics in field-conditioned concrete structures. 2) The relation of low ultrasound pulse velocities with high acoustoelastic effect and high magnitudes and variability of Slow-dynamics. 3) Different elastic behaviours on the north and south spans of the bridge, suggesting different heterogeneity levels on the analysed locations of the concrete beam.
KW - Concrete
KW - Ultrasound
KW - Nonlinear
KW - Elastic properties
KW - Damage
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640064
DO - https://doi.org/10.1007/s10921-025-01257-y
SN - 0195-9298
VL - 44
IS - 4
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-64006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Engelking, Lorenz
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Effect of heat control on mechanical properties and residual stresses at the transition zone of component and substrate in hybrid DED‑arc manufacturing
N2 - In hybrid additive manufacturing, components or semi-finished products manufactured by conventional primary forming are enhanced or modified by additive manufactured structures. However, systematic investigations focusing on the critical transition area between the specific properties of the substrate (like high-strength) and the additively manufactured component, made of specific filler material, are still lacking. The focus of the present study was to determine the influence of heat control on the Δt8/5 cooling time, the distortion, the mechanical properties, and the residual stresses in the transition area of hybrid-additive components. This contributed to the knowledge regarding the safe avoidance of cold cracking, excessive distortion, a reduction in yield stress, and the implementation of hybrid DED-arc manufacturing. The heat control was varied by means of heat input and working temperature such that the Δt8/5 cooling times corresponded to the recommended processing range. The heat input has a greater influence on the cooling time in the transition area than the working temperature. Working temperature and the total energy applied per layer have a significant effect on component distortion. The lowest working temperature of 100 °C in combination with the highest total energy per layer leads to significantly greater distortion compared to manufacturing with a high working temperature of 300 °C and low total energy per layer. In addition, the longitudinal residual compressive stresses in the sensitive transition area are reduced from − 500 MPa to approx. − 200 MPa by adjusting the working temperature from 100 to 300 °C. Such complex interactions must be clarified comprehensively to provide users with easily applicable processing recommendations and standard specifications for an economical hybrid additive manufacturing of components made, for example, of high-strength steels in the transition area.
T2 - IIW Annual Assembly and International Conference
CY - Rhodes Island, Greece
DA - 07.07.2024
KW - Hybrid additive manufacturing
KW - DED-arc
KW - Heat control
KW - High-strength metals
KW - Residual stress
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630415
DO - https://doi.org/10.1007/s40194-025-02036-z
SN - 1878-6669
SP - 1
EP - 15
PB - Springer
AN - OPUS4-63041
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krahl, T.
A1 - Beer, F.
A1 - Relling, A.
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
A1 - Kemnitz, E.
T1 - Toward Luminescent Composites by Phase Transfer of SrF2 :Eu3+ Nanoparticles Capped with Hydrophobic Antenna Ligands
N2 - Transparent dispersions of hydrophobic SrF2 :Eu3+ nanoparticles in cyclohexane with up to 20% europium were obtained by fluorolytic sol-gel synthesis followed by Phase transfer into cyclohexane through capping with sodium dodecylbenzenesulfonate (SDBS). The particles were characterized by TEM, XRD and DLS as spherical objects with a diameter between 6 and 11 nm in dry state. 1H-13CP MAS NMR experiments revealed the binding of the anionic sulfonate head group to the particle surface. The particles show bright red luminescence upon excitation of the aromatic capping agents, acting as antennas for an Energy transfer from the benzenesulfonate unit to the Eu3+ centers in the particles. This synthesis method overcomes the current obstacle of the fluorolytic sol-gel synthesis that transparent dispersions can be obtained directly only in hydrophilic solvents. To demonstrate the potential of such hydrophobized alkaline-earth fluoride particles, transparent luminescent organic-inorganic composites with 10% SrF2 :Eu3+ embedded into polyTEGDMA, polyBMA, poly-BDDMA and polyD3MA, respectively, were prepared, endowing the polymers with the luminescence features of the nanoparticles.
KW - Nanoparticles
KW - Fluorides
KW - Sol-gel process
KW - Organic-inorganic hybrid composites
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508668
DO - https://doi.org/10.1002/cnma.202000058
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-50866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cao, L.
A1 - Thome, P.
A1 - Agudo Jácome, Leonardo
A1 - Somsen, C.
A1 - Cailletaud, G.
A1 - Eggeler, G.
T1 - On the influence of crystallography on creep of circular notched single crystal superalloy specimens
N2 - The present work contributes to a better understanding of the effect of stress multiaxiality on the creep behavior of single crystal Ni-base superalloys. For this purpose we studied the creep deformation and rupture behavior of double notched miniature creep tensile specimens loaded in three crystallographic directions [100], [110] and [111] (creep conditions: 950 °C and 400 MPa net section stress). Crystal plasticity finite element method (CPFEM) was used to analyze the creep stress and strain distributions during creep. Double notched specimens have the advantage that when one notch fails, the other is still intact and allows to study a material state which is close to rupture. No notch root cracking was observed, while microstructural damage (pores and micro cracks) were frequently observed in the center of the notch root region. This is in agreement with the FEM results (high axial stress and high hydrostatic stress in the center of the notched specimen). Twinning was observed in the notch regions of [110] and [111] specimens, and <112> {111} twins were detected and analyzed using orientation imaging scanning electron microscopy. The present work shows that high lattice rotations can be detected in SXs after creep fracture, but they are associated with the high strains accumulated in the final rupture event.
KW - Single crystal Ni-Base superalloys
KW - Double notched creep specimen
KW - Stress distribution
KW - Lattice rotation
KW - Cracks
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506060
DO - https://doi.org/10.1016/j.msea.2020.139255
SN - 0921-5093
VL - 782
SP - 139255
PB - Elsevier B. V.
AN - OPUS4-50606
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan-Scherb, Christiane
A1 - Menneken, Martina
A1 - Weber, Kathrin
A1 - Agudo Jácome, Leonardo
A1 - Nolze, Gert
T1 - Elucidation of orientation relations between Fe-Cr alloys and corrosionproducts after high temperature SO2 corrosion
N2 - The early stages of corrosion of Fe-Cr-model alloys (2 and 9 % Cr) were investigated after exposure at 650 °C in0.5 % SO2containing gas by electron backscattered diffraction (EBSD) and transmission electron microscopy(TEM). The impact of the grain orientation of the base alloy on the orientation relations of the corrosion productsis presented. After 2 min–5 min exposure the formation of a multi-layered corrosion zone was discovered. Aclear orientation relationship between ferrite and the (Fe,Cr)3O4 spinel could be demonstrated. The obtainedresults show the importance of the grain orientation on oxidation resistance.
KW - Iron
KW - TEM
KW - SEM
KW - High temperature corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508911
DO - https://doi.org/10.1016/j.corsci.2020.108809
VL - 174
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-50891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tjaden, B.
A1 - Lisec, Jan
A1 - Schramm, A.
T1 - N-Myc-induced metabolic rewiring creates novel therapeutic vulnerabilities in neuroblastoma
N2 - N-Myc is a transcription factor that is aberrantly expressed in many tumor types and is often correlated with poor patient prognosis. Recently, several lines of evidence pointed to the fact that oncogenic activation of Myc family proteins is concomitant with reprogramming of tumor cells to cope with an enhanced need for metabolites during cell growth. These adaptions are driven by the ability of Myc proteins to act as transcriptional amplifiers in a tissue-of-origin specific manner. Here, we describe the effects of N-Myc overexpression on metabolic reprogramming in neuroblastoma cells. Ectopic expression of N-Myc induced a glycolytic switch that was concomitant with enhanced sensitivity towards 2-deoxyglucose, an inhibitor of glycolysis. Moreover, global metabolic profiling revealed extensive alterations in the cellular metabolome resulting from overexpression of N-Myc. Limited supply with either of the two main carbon sources, glucose or glutamine, resulted in distinct shifts in steady-state metabolite levels and significant changes in glutathione metabolism. Interestingly, interference with glutamine-glutamate conversion preferentially blocked proliferation of N-Myc overexpressing cells, when glutamine levels were reduced. Thus, our study uncovered N-Myc induction and nutrient levels as important metabolic master switches in neuroblastoma cells and identified critical nodes that restrict tumor cell proliferation.
KW - Mass-Spectrometry
KW - Cancer
KW - MYCN
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507193
DO - https://doi.org/10.1038/s41598-020-64040-1
VL - 10
IS - 1
SP - 7157
AN - OPUS4-50719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Hecht, Mandy
A1 - Witthuhn, Heike
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Mix‐&‐read determination of Mercury(II) at trace levels with hybrid mesoporous silica materials incorporating fluorescent probes by a simple mix‐&‐load technique
N2 - The synthesis, characterization, and application of mesoporous materials containing boron–dipyrromethene (BODIPY) moieties that allow the sensitive and selective detection of HgII in aqueous environments by fluorescence enhancement is reported. For this purpose, BODIPY dye I containing a thia‐aza crown ether receptor as the fluorescent probe for the detection of HgII in aqueous environments is encapsulated into mesoporous materials to avoid self‐quenching or aggregation in water. Determination of HgII is accomplished within a few seconds with high selectivity and sensitivity, reaching a limit of detection of 12 ppt. The determination of trace amounts of HgII in natural waters and in fish extracts is demonstrated by using our sensing material. The incorporation of the material into several μ‐PAD strips yields a portable, cheap, quick, and easy‐to‐handle tool for trace HgII analysis in water.
KW - Dyes/pigments
KW - Test strips
KW - Mesoporous materials
KW - Mercury
KW - Fluorescence
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-460138
DO - https://doi.org/10.1002/open.201800277
SN - 2191-1363
VL - 7
IS - 12
SP - 957
EP - 968
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-46013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alnajjar, M. A.
A1 - Bartelmeß, Jürgen
A1 - Hein, R.
A1 - Ashokkumar, Pichandi
A1 - Nilam, M.
A1 - Nau, W. M.
A1 - Rurack, Knut
A1 - Hennig, A.
T1 - Rational design of boron-dipyrromethene (BODIPY) reporter dyes for cucurbit[7]uril
N2 - We introduce herein boron-dipyrromethene (BODIPY) dyes as a new class of fluorophores for the design of reporter dyes for supramolecular host–guest complex formation with cucurbit[7]uril (CB7). The BODIPYs contain a protonatable aniline nitrogen in the meso-position of the BODIPY chromophore, which was functionalized with known binding motifs for CB7. The unprotonated dyes show low fluorescence due to photoinduced electron transfer (PET), whereas the protonated dyes are highly fluorescent. Encapsulation of the binding motif inside CB7 positions the aniline nitrogen at the carbonyl rim of CB7, which affects the pKa value, and leads to a host-induced protonation and thus to a fluorescence increase. The possibility to tune binding affinities and pKa values
is demonstrated and it is shown that, in combination with the beneficial photophysical properties of BODIPYs, several new applications of host–dye reporter pairs can be implemented. This includes indicator displacement assays with favourable absorption and
emission wavelengths in the visible spectral region, fluorescence correlation spectroscopy, and noncovalent surface functionalization
with fluorophores.
KW - BODIPY
KW - Cucurbituril
KW - Fluorescence
KW - PH
KW - Photoinduced Electron Transfer
KW - Supramolecular Chemistry
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456361
UR - https://www.beilstein-journals.org/bjoc/content/pdf/1860-5397-14-171.pdf
DO - https://doi.org/10.3762/bjoc.14.171
SN - 1860-5397
VL - 14
SP - 1961
EP - 1971
PB - Beilstein-Institut
CY - Frankfurt a. M.
AN - OPUS4-45636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eggeler, G.
A1 - Wieczorek, N.
A1 - Fox, F.
A1 - Berglund, S.
A1 - Bürger, D.
A1 - Dlouhý, A.
A1 - Wollgramm, P.
A1 - Neuking, K.
A1 - Schreuer, J.
A1 - Agudo Jácome, Leonardo
A1 - Gao, S.
A1 - Hartmaier, A.
A1 - Laplanche, G.
T1 - On shear testing of single crystal Ni-base superalloys
N2 - Shear testing can contribute to a better understanding of the plastic deformation of Ni-base superalloy single crystals. In the present study, shear testing is discussed with special emphasis placed on its strengths and weaknesses. Key mechanical and microstructural results which were obtained for the high-temperature (T ≈ 1000 °C) and low-stress (τ ≈ 200 MPa) creep regime are briefly reviewed. New 3D stereo STEM images of dislocation substructures which form during shear creep deformation in this regime are presented. It is then shown which new aspects need to be considered when performing double shear creep testing at lower temperatures (T < 800 °C) and higher stresses (τ > 600 MPa). In this creep regime, the macroscopic crystallographic [11−2](111) shear system deforms significantly faster than the [01−1](111) system. This represents direct mechanical evidence for a new planar fault nucleation scenario, which was recently suggested (Wu et al. in Acta Mater 144:642–655, 2018). The double shear creep specimen geometry inspired a micro-mechanical in-situ shear test specimen. Moreover, the in-situ SEM shear specimen can be FIB micro-machined from prior dendritic and interdendritic regions. Dendritic regions, which have a lower γ′ volume fraction, show a lower critical resolved shear stress.
T2 - EuroSuperalloys 2018
CY - Oxford, UK
DA - 09.09.2018
KW - Superalloy single crystals
KW - Shear testing
KW - Creep mechanisms
KW - In-situ SEM micro shear deformation
KW - Transmission electron microscopy
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456591
DO - https://doi.org/10.1007/s11661-018-4726-9
SN - 1073-5623
SN - 1543-1940
VL - 49A
IS - 9
SP - 3951
EP - 3962
PB - Springer US
CY - New York
AN - OPUS4-45659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Die 3D-Mikrofluidik mit molekular geprägten Polymerpartikeln eröffnet
neue Möglichkeiten der selektiven Pestizid-Bestimmung in Wasser
N2 - 2,4-D ist ein in der Landwirtschaft weitverbreitetes Pflanzenschutzmittel, das Grundwasser kontaminiert, sich innerhalb der Nahrungskette anreichert und Umwelt- und Gesundheitsprobleme verursachen kann. Hier stellen die Autoren ein mikrofluidisches Nachweissystem für die Echtzeitdetektion von 2,4-D in Grund- oder Oberflächenwasser vor. Es basiert auf der Kombination 2,4-D-selektiver, fluoreszierender, molekular geprägter Polymer-(MIP-)Mikropartikel mit einem 3D-mikrofluidischen Extraktions- und Detektionssystem. Messungen vor Ort sollen damit künftig möglich sein.
KW - 3D-Mikrofluidik
KW - Sensorpartikel
KW - MIP
KW - Pestizid
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444781
UR - https://www.labo.de/epaper/LA0318/index.html
SN - 0344-5208
IS - 3
SP - 10
EP - 13
PB - WEKA Business Medien GmbH
AN - OPUS4-44478
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Mit Tröpfchen Spielen
N2 - Mikrofluidische Systeme sind leistungsstarke analytische Tools mit attraktiven Eigenschaften wie miniaturisierter Größe, geringem Reagenzien und Probenverbrauch, schneller Ansprech- und kurzer Messzeit. Der Bedarf solcher leistungsstarken, miniaturisierten und direkt vor Ort anwendbaren Sensorsysteme steigt kontinuierlich, hauptsächlich durch das Bedürfnis der Gesellschaft, schneller, besser und umfassender über kritische Faktoren im Lebens- und Arbeitsumfeld sowie der Umwelt informiert zu sein.
KW - Mikrofluidik
KW - Sensorpartikel
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459120
UR - https://www.git-labor.de/forschung/umwelt/mit-troepfchen-spielen
VL - 8
IS - 8
SP - 2
EP - 4
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim, Deutschland
AN - OPUS4-45912
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Playing with Droplets
N2 - Microfluidic devices are powerful analytical tools with appealing features such as miniaturized size, low reagent and sample consumption, rapid response and short measurement times. As society wants to be ever better, earlier and more comprehensively informed about critical factors in life, work, and the environment, the demand for powerful measurement devices for use outside of the laboratory constantly increases.
KW - Microfluidics
KW - Sensory particles
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459131
UR - https://www.laboratory-journal.com/
VL - 4
SP - 2
EP - 4
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim, Deutschland
AN - OPUS4-45913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Hecht, Mandy
A1 - Witthuhn, Heike
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Cover profile for the article "Mix‐&‐read determination of Mercury(II) at trace levels with hybrid mesoporous silica materials incorporating fluorescent probes by a simple mix‐&‐load technique"
N2 - Invited for this month’s cover picture is the group of Dr. Knut Rurack at the Department of Analytical Chemistry; Reference Materials at the Bundesanstalt fuer Materialforschung und -pruefung (BAM) in Berlin (Germany). The cover picture shows how differences in color and fluorescence on a test strip can be easily read out with a mobile device. Two reference spots Frame the sensitive spot that indicates the presence of trace amounts of HgII below the threshold in a natural water sample. This dipstick contains a hybrid material that combines boron-dipyrromethene (BODIPY) probes sterically loaded into specifically tailored mesoporous silica particles, allowing for ultrasensitive HgII detection through enhanced fluorescence in a few seconds. The applicability in real water samples and fish extracts are also studied.
KW - Mercury
KW - Fluorescence
KW - Dip-stick assay
KW - Group profile
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471267
DO - https://doi.org/10.1002/open.201800231
SN - 2191-1363
VL - 7
IS - 12
SP - 932
EP - 933
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-47126
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Rurack, Knut
T1 - Streifenschnelltest mit ppt-Empfindlichkeit durch Kombination von Elektrochemilumineszenz-Detektion mit Aptamer-gesteuerter Indikatorfreisetzung aus mesoporösen Nanopartikeln
N2 - Die Kombination aus elektrogenerierter Chemilumineszenz (ECL) und Aptamer-gesteuerter Indikatorfreisetzung (gAID) aus magnetischen mesoporösen Silica-Nanopartikeln, die in mit Poly(ethylenglycol) und N-(3-Triethoxysilylpropyl) diethanolamin funktionalisiertes Glasfaserpapier eingebettet sind, ermöglichte die Entwicklung eines Schnelltests, mit dem sich Penicillin direkt in verdünnter Milch bis auf 50 +/- 9 ppt in <5 min nachweisen lässt. Die kovalente Bindung der Aptamer-Kappe an das Siliciumdioxid-Gerüst ermöglichte den Verschluss der Poren durch nicht-kovalente elektrostatische Wechselwirkungen mit Oberflächen-Aminogruppen. Die Bindung von Penicillin führte zu einer Faltung des Aptamers, wodurch der zuvor in das Material geladene ECL-Reporter Ru(bpy)32+ freigesetzt wurde und nach lateralem Fluss von einer Smartphone-Kamera nach elektrochemischer Anregung mit einer in einen 3D-gedruckten Halter eingesetzten Siebdruckelektrode detektiert wird. Der Ansatz ist einfach, generisch und bietet Vorteile hinsichtlich Empfindlichkeit, Messunsicherheit und Robustheit gegenüber konventioneller Fluoreszenz- oder elektrochemischer Detektion, insbesondere für Point-of-Need-Analysen anspruchsvoller Matrices und Analyten im Ultraspurenbereich.
KW - Schnelltests
KW - Elektrochemilumineszenz
KW - Aptamere
KW - Teststreifen
KW - Gesteuerte Freisetzung
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540205
DO - https://doi.org/10.1002/ange.202110744
VL - 133
IS - 50
SP - 26491
EP - 26501
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54020
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smeir, E.
A1 - Leberer, S.
A1 - Blumrich, A.
A1 - Vogler, G.
A1 - Vasiliades, A.
A1 - Dresen, S.
A1 - Jaeger, Carsten
A1 - Gloaguen, Y.
A1 - Klose, C.
A1 - Beule, D.
A1 - Schulze, P.
A1 - Bodmer, R.
A1 - Foryst-Ludwig, A.
A1 - Kintscher, U.
T1 - Depletion of Cardiac Cardiolipin Synthase Alters Systolic and Diastolic Function
N2 - Cardiolipin (CL) is a major cardiac mitochondrial phospholipid maintaining regular mitochondrial morphology and function in cardiomyocytes. Cardiac CL production includes ist biosynthesis and a CL-remodeling process. Here we studied the impact of CL-biosynthesis and the enzyme Cardiolipin Synthase (CLS) on cardiac function.
CLS and cardiac CL-species were significantly downregulated in cardiomyocytes following catecholamine-induced cardiac damage in mice, accompanied by increased oxygen consumption rates, signs of oxidative stress and mitochondrial uncoupling. RNAi-mediated cardiomyocyte-specific knockdown of CLS in Drosophila melanogaster resulted in marked cardiac dilatation, severe impairment of systolic performance and slower diastolic filling velocity assessed by fluorescence-based heart imaging. Finally, we showed that CL72:8 is significantly decreased in cardiac samples from patients with heart failure with reduced ejection fraction (HFrEF). In summary, we identified CLS as a regulator of cardiac function. Considering the cardiac depletion of CL-species in HFrEF, pharmacological targeting of CLS may be a promising therapeutic approach.zeige mehrzeige weniger
KW - High-resolution mass spectrometry
KW - Nontarget analysis
KW - Heart failure
KW - Cardiolipins
KW - Lipidomics
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536833
DO - https://doi.org/10.1016/j.isci.2021.103314
VL - 24
IS - 11
SP - 103314
PB - Cell Press
AN - OPUS4-53683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hudson, A.D.
A1 - Jamieson, O.
A1 - Crapnell, R.D.
A1 - Rurack, Knut
A1 - Soares, T.C.C.
A1 - Mecozzi, F.
A1 - Laude, A.
A1 - Gruber, J.
A1 - Novakovic, K.
A1 - Peeters, M.
T1 - Dual detection of nafcillin using a molecularly imprinted polymer-based platform coupled to thermal and fluorescence read-out
N2 - Reported here is the production of molecularly imprinted polymer (MIP) films, integrating a fluorescent moiety that serves as both an element for template interaction and signalling, for the thermal and optical detection of the beta-lactam antibiotic nafcillin. Fluorescein methacrylate (FluMa) was synthesized and introduced during the molecular imprinting process as the sole monomer and in a 1 : 1 mixture with methacrylic acid (MAA), allowing to draw first conclusions on the MIP formation potential of such a rather large and rigid monomer. At first, MIP microparticles containing FluMa were prepared by free radical polymerisation. Optical batch rebinding experiments revealed that FluMa can act as a functional monomer for selective detection of nafcillin; however, the addition of MAA as co-monomer significantly improved performance. Subsequently, thin MIP films containing FluMa were deposited onto functionalised glass slides and the influence of porogen, drying time, and monomer composition was studied. These MIP-functionalised glass electrodes were mounted into a customised 3D-printed flow cell, where changes in the liquid were either evaluated with a thermal device or using fluorescence bright field microscopy. Thermal analysis demonstrated that multiple MIP layers enhanced sensor specificity, with detection in the environmentally relevant range. The fluorescence bright field microscope investigations validated these results, showing an increase in the fluorescence intensity upon exposure of the MIP-functionalised glass slides to nafcillin solutions. These are promising results for developing a portable sensor device that can be deployed for antibiotics outside of a dedicated laboratory environment, especially if sensor design and fluorophore architecture are optimised.
KW - Molecularly Imprinted Polymers
KW - Fluorescence
KW - Antibiotics
KW - Heat-transfer Measurements
KW - Thin films
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540044
DO - https://doi.org/10.1039/D1MA00192B
VL - 2
IS - 15
SP - 5105
EP - 5115
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-54004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kingsbery, Phillip
A1 - Stephan-Scherb, Christiane
T1 - Effect of KCl deposits in high‐temperature corrosion on chromium‐rich steels in SO2‐containing atmosphere
N2 - High‐temperature corrosion was studied under multiple chemical loads on ferritic‐austenitic model alloys (Fe–13Cr, Fe–18Cr–12Ni, and Fe‐25Cr–20Ni) with KCl deposit under 0.5% SO2/99.5% Ar gas atmosphere at 560°C. Postexposure characterization was done by X‐ray diffraction and scanning electron microscopy. In a pure SO2/Ar environment a protective Cr2O3 scale was formed by all samples. The introduction of KCl deposits causes the scale to be nonprotective and multilayered, consisting of CrS, FeS, Cr2O3, Fe3O4, and Fe2O3. The impact of the microstructure and alloying elements is discussed.
KW - High‐temperature corrosion
KW - KCl
KW - Microstructure
KW - SO2
KW - Steel alloy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543056
DO - https://doi.org/10.1002/maco.202112901
VL - 73
IS - 5
SP - 758
EP - 770
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54305
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manzoni, Anna Maria
A1 - Dubois, F.
A1 - Mousa, M. S.
A1 - von Schlippenbach, C.
A1 - Többens, D. M.
A1 - Yesilcicek, Yasemin
A1 - Zaiser, E.
A1 - Hesse, René
A1 - Haas, S.
A1 - Glatzel, U.
T1 - On the Formation of Eutectics in Variations of the Al10Co25Cr8Fe15Ni36Ti6 Compositionally Complex Alloy
N2 - Superalloy inspired Al10Co25Cr8Fe15Ni36Ti6 compositionally complex alloy is known for its gamma-gamma' microstructure and the third Heusler phase. Variations of this alloy, gained by replacing 0.5 or 1 at. pct Al by the equivalent amount of Mo, W, Zr, Hf or B, can show more phases in addition to this three-phase morphology. When the homogenization temperature is chosen too high, a eutectic phase formation can take place at the grain boundaries, depending on the trace elements: Mo and W do not form eutectics while Hf, Zr and B do. In order to avoid the eutectic formation and the potential implied grain boundary weakening, the homogenization temperature must be chosen carefully by differential scanning calorimetry measurements. A too low homogenization temperature, however, could impede the misorientation alignment of the dendrites in the grain. The influence of grain boundary phases and incomplete dendrite re-orientation are compared and discussed.
KW - High entropy alloy
KW - Eutectic
KW - Homogenization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543504
DO - https://doi.org/10.1007/s11661-020-06091-7
VL - 52
IS - 1
SP - 143
EP - 150
PB - Springer
AN - OPUS4-54350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koniorczyk, M.
A1 - Bednarska, Dalia
A1 - Wieczorek, A.
A1 - Materak, K.
T1 - Probabilistic approach to concrete durability based on combined stochastic differential equations and Monte Carlo method
N2 - Cementitious materials are often exposed to aggressive environments, which have a significant impact on their durability. Proper prediction of concrete corrosion helps to apply the right measures and technologies, to extend the service life of structures. Carbonation and cyclic freezing are recognized among the most common corrosive factors for concrete. Their progress is linked to the penetration of CO2 and water into the concrete structure. Due to the random arrangement of aggregates and cement paste, concrete is an inhomogeneous material. Therefore, the progress of carbonation and frost-induced damage should be treated as random variables with appropriate probabilistic parameters. Experimental studies on concrete carbonation and freezing were conducted in accordance with the standards EN 12390–12 and EN 12390–9. As observed in the experiments, the progress of carbonation and frost damage of concrete could be described by zigzag, not necessarily monotonic functions. Stochastic differential equations (SDE) were employed to predict the behavior of concrete exposed to elevated CO2 concentrations and cyclic freezing. The stochastic model consisted of a drift term, which described the general trend of concrete durability exposed to carbonation and frost cycles, as well as a diffusion term, which accounted for the stochastic features of inhomogeneous concrete microstructure. The Euler–Maruyama approximation with Milstein improvement was applied to model the realization of the stochastic changes in concrete microstructure/durability. The proposed approach predicted experimental results with high accuracy. The application of the Monte Carlo (MC) method with 100,000 SDE realizations allowed to calculate the statistical parameters of the processes, such as concrete carbonation and freezing cycles. The probabilistic parameters, such as expected values and standard deviations, calculated using the SDE_MC approach, were in good agreement with experimental results for both problems, i.e. decelerating concrete carbonation and accelerating concrete scaling.
KW - Concrete durability
KW - Concrete carbonation
KW - Concrete scaling
KW - Time-dependent random variable
KW - Stochastic differential equations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643417
DO - https://doi.org/10.1007/s43452-025-01335-y
SN - 2083-3318
VL - 25
IS - 5-6
SP - 1
EP - 31
PB - Springer Nature Switzerland AG
CY - Schweiz
AN - OPUS4-64341
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baeßler, Matthias
A1 - Ebell, Gino
A1 - Herrmann, Ralf
A1 - Hille, Falk
A1 - Schneider, Ronald
ED - Lienhart, Werner
ED - Krüger, Markus
T1 - On potentials and challenges of physics-informed SHM for civil engineering structures
N2 - Physics-informed structural health monitoring, which integrates realistic physical models of material behavior, structural response, damage mechanisms, and aging processes, offers a promising approach to improve monitoring capabilities and inform operation and maintenance planning. However, the associated technical challenges and model requirements are context-specific and vary widely across applications. To illustrate the relevance and potential of the topic, two application examples are presented. The first focuses on monitoring the modal characteristics of a prestressed road bridge, where strong sensitivity to temperature variations limits the diagnostic capabilities of conventional vibration-based global monitoring. The discussion highlights how environmental influences can obscure structural changes, and emphasizes that purely data-based approaches are inherently limited to detecting anomalies and do not enable comprehensive condition diagnostics. The second example explores a physics-informed monitoring approach for prestressed concrete bridges affected by hydrogen-induced stress corrosion cracking.
T2 - SHMII-13
CY - Graz, Austria
DA - 01.09.2025
KW - Hydrogen Stress Corrosion Cracking
KW - SHM
KW - Physics informed
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643271
SN - 978-3-99161-057-1
DO - https://doi.org/10.3217/978-3-99161-057-1-039
SP - 245
EP - 251
PB - Verlag der Technischen Universität Graz
CY - Graz, Austria
AN - OPUS4-64327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Frank A.
A1 - Hille, Falk
A1 - Glisic, Branco
ED - Lienhart, Werner
ED - Krüger, Markus
T1 - Global Perspectives on Structural Monitoring in Civil Engineering
N2 - Structural Monitoring (SM) is crucial in civil engineering for ensuring the safety, functionality, and longevity of civil infrastructure, especially bridges. As its importance grows, SM practices are guided mainly by national standards, leading to fragmented approaches and limited global integration. This paper examines SM guidelines, focusing on contributions from Germany, while exploring the broader international framework.
In Germany, key guidelines such as the DGZfP Merkblatt B09 and others offer structured methods and practice examples for long-term monitoring and performance assessment. Internationally, countries have developed their own SM frameworks. Amongst others, Austria’s RVS Richtlinie 13.03.01, France’s COFREND Livre Blanc, Canada’s ISIS Guidelines, the ACI Report 444.2-21 from the USA, the TRB Circular E-C246 and the CIRIA Guideline from the UK contribute to a global understanding of SM. These guidelines address common technical, theoretical, and economic challenges across regions.
This paper highlights the need for international collaboration, identifying synergies and gaps to promote a unified approach to SM. It offers insights into global standards and how successful strategies can foster innovation and cohesion in SM practices worldwide.
T2 - 13th International Conference on Structural Health Monitoring of Intelligent Infrastructure
CY - Graz, Austria
DA - 01.09.2025
KW - Structural Health Monitoring
KW - bridge structures
KW - guidelines
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643859
DO - https://doi.org/10.3217/978-3-99161-057-1-063
SP - 411
EP - 419
PB - Verlag der Technischen Universität Graz
AN - OPUS4-64385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hille, Falk
A1 - Wedel, Frederik
A1 - Lehmann, Frank A.
A1 - Pirskawetz, Stephan
ED - Lienhart, Werner
ED - Krüger, Markus
T1 - Structural health monitoring guidelines for bridges in Germany
N2 - With the advancement of digitalization and related technological developments, Structural Health Monitoring (SHM) has become a useful and increasingly widespread tool to assist in the maintenance management of bridges and other engineering structures. The process of implementing monitoring requires expertise in many fields such as civil engineering, bridge operation and maintenance, monitoring technology, and data analysis. In recent years, monitoring has moved from method and technology development to standard practice. However, the implementation of monitoring as a standardized process can be an obstacle, especially for bridge operators, due to a lack of practical experience combined with the various expertise required. This can affect several areas, such as determining the cost-effectiveness of a monitoring measure, proper tendering and contracting, quality control, analysis and evaluation of measurement data, and last but not least, data management. In order to support the introduction of monitoring technologies into the practice of infrastructure operators, several guidelines have been developed in Germany in recent years by different interest groups, each with a different focus and essentially complementing each other. This paper aims to provide an overview of four different recently published guidelines and to highlight their strengths and advantages.
T2 - 13th International Conference on Structural Health Monitoring of Intelligent Infrastructure
CY - Graz, Austria
DA - 01.09.2025
KW - Structural Health Monitoring
KW - Bridge structures
KW - Guidelines
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643809
DO - https://doi.org/10.3217/978-3-99161-057-1-064
SP - 420
EP - 427
PB - Verlag der Technischen Universität Graz
AN - OPUS4-64380
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Nina
A1 - Rhode, Michael
A1 - Kannengießer, Thomas
A1 - Kromm, Arne
A1 - Kadoke, Daniel
A1 - Kruse, Julius
T1 - Effect of Ti microalloying on the local strain behavior of cross-weld tensile samples determined by digital image correlation
N2 - High-strength low-alloyed (HSLA) steels with yield strength / proof stress ≥ 600 MPa are the basis of modern light-weight steel constructions. Indeed, the economic and ecological benefits strongly depend on their processability in terms of welding. In this context, the use of highly productive welding processes and suitable welding consumables is of vital interest and requires a fundamental understanding of the microstructural changes in the HSLA steel and especially the heat-affected zone (HAZ) of the welded joint. Microalloying elements, such as Ti or Nb, are essential to achieve the desired mechanical properties. To analyse the weldability, three-layer welds were performed using gas metal arc welding (GMAW) and critical microstructures, such as areas of the HAZ that exhibit significant softening or hardening, were identified. The effect of the softened HAZ region on failure was evaluated using cross-weld tensile specimens. Digital image correlation (DIC) was used for in-situ monitoring of the development and accumulation of the local strains in different HAZ regions during tensile testing. Using a specially designed mirror system, the local strains of the microstructure zones on the top and bottom of the weld were recorded simultaneously. In addition, the analysis of the local deformation helps to understand the effects of the softened HAZ on the global strain, the reduction in area, the fracture position, and the overall fracture behavior.
KW - High-strength structural steel
KW - Microalloying influences
KW - HAZ-softening
KW - Digital Image Correlation
KW - Constraint effect
KW - Thermodynamic simulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643558
DO - https://doi.org/10.1007/s40194-025-02185-1
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-64355
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dell’Avvocato, G.
A1 - Amiel, S.
A1 - Maillard, S.
A1 - Mayr, G.
A1 - Oswald-Tranta, B.
A1 - Colinas, E.
A1 - Svantner, M.
A1 - Bouteille, P.
A1 - Huillery, R.
A1 - Galietti, U.
A1 - Deganova, L.
A1 - Caulier, Y.
A1 - Ziegler, Mathias
ED - Sakagami, T.
ED - Inoue, H.
T1 - Advancing Active Thermography for NDT: The Role of Standardization
N2 - Infrared thermography, particularly its active form, is increasingly used in various industries in non-destructive testing (NDT). To support its broader adoption, structured standardization efforts have been developed within CEN/TC 138/WG11 and coordinated with ISO. Key standards—such as EN 16714, EN 17119, and EN 17501—define principles, procedures, and equipment requirements. Current activities include finalizing the draft on induction thermography, revising EN 17119, and developing new projects on optical lock-in, laser weld inspection, and thermal diffusivity. Standardization enhances comparability, reliability, and certification, making thermography a robust and scalable solution within the global NDT framework.
T2 - AITA 2025
CY - Kobe, Japan
DA - 15.09.2025
KW - Active thermography
KW - Non-destructive testing (NDT)
KW - Standardization
KW - CEN/TC 138/WG11
KW - Infrared inspection
KW - Industrial qualification
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643972
DO - https://doi.org/10.3390/proceedings2025129030
VL - 129
IS - 1
SP - 1
EP - 4
PB - MDPI
CY - Basel Switzerland
AN - OPUS4-64397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poka, Konstantin
A1 - Ali, Sozol
A1 - Ulbricht, Alexander
A1 - Schröder, Jakob
A1 - Khambayat, Jiganesh
A1 - Scholz, Maik
A1 - Saeed, Waleed
A1 - Merz, Benjamin
A1 - Epperlein, Martin
A1 - Hilgenberg, Kai
T1 - Reduction of extraneous variance in powder bed fusion with laser beam of metals by means of advanced digital preprocessing
N2 - Data-driven quality assurance and reproducibility are critical for advancing the industrial maturity of Powder Bed Fusion with Laser Beam of Metals (PBF-LB/M). This study addresses the extraneous variance in scan vectors that arises even for identical cross sections of nominally identical components but located at different positions on the build platform. This inherent variance, common across most PBF-LB/M machines, is caused by scan vector computation relative to the machine coordinate origin and subsequent projection of the resulting pattern onto individual component cross sections. In this work, scan vectors are computed still following conventional slicing, but relative to the workpiece origin of each component, using an EOS M 300-4. This digital preprocessing approach homogenizes fabrication conditions, ensuring that anomalies, such as scan vector overlaps, occur consistently across identical components. The impact during fabrication is assessed through powder bed imaging, melt pool monitoring, and operational data from the multilaser PBF-LB/M machine. Components are manufactured from AlSi10Mg for each scan vector computation origin and subsequently qualified using x-ray computed tomography, optical coordinate measurement, and optical surface measurement. A comprehensive evaluation is conducted, comparing the results in terms of component density, geometric accuracy, and surface roughness to those obtained using conventional preprocessing. Based on these findings, practical recommendations are provided, focusing on achieved quality criteria to identify potential drawbacks, while also considering the life cycle analysis of fabrication. Finally, the study emphasizes the significance of consistent scan vector provisioning for identical components placed at different build platform positions, assuming no roll or pitch during nesting.
T2 - ICALEO
CY - Orlando, FL, USA
DA - 13.10.2025
KW - Quality assurance
KW - Data management
KW - 3D printing
KW - Laser fabrication
KW - Life cycle analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642104
DO - https://doi.org/10.2351/7.0001890
SN - 1042-346X
VL - 37
IS - 4
SP - 1
EP - 14
PB - American Institute of Physics Publishing
CY - New York
AN - OPUS4-64210
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dalichow, Dirk
A1 - Blaschke, Jil
A1 - Wilsch, Gerd
A1 - Völker, Tobias
T1 - Revolutionizing Concrete Analysis and Maintenance with Laser-Induced Breakdown Spectroscopy
N2 - Laser-induced breakdown spectroscopy (LIBS) is a valuable complement to established methods for the chemical analysis of concrete. Compared to conventional techniques, LIBS enables spatially resolved imaging of harmful ion distributions within the cementitious matrix. It allows the simultaneous detection of all relevant ions and degradation mechanisms, facilitating a better understanding of interacting processes. The benefits of multi-element analysis are illustrated through selected examples that highlight the method’s superior information content. Ion penetration profiles are recorded at a resolution of 0.25 mm, providing high-quality input data for service life modelling. Instead of drill dust, a 50 mm core sample is used. The measurement is automated, requires no chemical reagents or elaborate sample preparation, and is completed within minutes.
KW - LIBS
KW - Durability
KW - Ion transport profiling
KW - Concrete analysis
KW - Service life assessment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642846
DO - https://doi.org/10.58286/31656
SN - 1435-4934
VL - 30
IS - 10
SP - 1
EP - 8
PB - NDT.net GmbH & Co. KG
AN - OPUS4-64284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schönsee, Eric
A1 - Hüsken, Götz
A1 - Kocherla, Amarteja
A1 - Strangfeld, Christoph
T1 - A framework for characterising the reflection intensity of a 3D-CP mortar
N2 - The growing interest of 3D Concrete Printing (3DCP) arises new challenges for quality control. A major challenge lies in evaluation of the interlayer bond strength. An optical approach is developed to monitor the surface properties of the printed layer. Commercial laser profile scanners are utilised to record the reflection intensity of the mortar’s surface. To be applicable in the printing process, the reflection intensity needs to be characterised for each material within the printable region and further effects, like geometry and environmental light, need to be considered. The presented work aims to provide a framework for implementing the laser reflection intensity to 3DCP monitoring.
T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Izmir, Türkiye
DA - 24.09.2025
KW - 3D Concrete Printing
KW - In Situ Measurements
KW - Laser reflection intensity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643047
DO - https://doi.org/10.58286/31728
SN - 1435-4934
SP - 1
EP - 4
PB - NDT.net
AN - OPUS4-64304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heide, Maximilian
A1 - Reifenrath, Jonas
A1 - Herrmann, Alexander
A1 - Engelhard, Carsten
T1 - Fast and Sustainable Active Pharmaceutical Ingredient (API) Screening in Over-the-Counter and Prescription Drug Products by Surface-Assisted Plasma-Based Desorption/Ionization High-Resolution Mass Spectrometry
N2 - Fast chemical analysis of pharmaceutical preparations is important for quality assurance, counterfeit drug detection, and consumer health. While quantitative methods such as high-performance liquid chromatography mass spectrometry (HPLC-MS) are powerful, there is a need for sustainable and environmentally friendly methods, which require less chemicals and produce less waste. Here, solvent-free ambient desorption/ionization (ADI) MS methods are attractive because they do not require time-consuming chromatography, produce little to no chemical waste, and, thus, contribute to green chemistry practice. In addition, sample throughput can be higher compared to HPLC-MS. In this study, a method for direct analysis of single- and multi agent drugs using a plasma-based ADI source (flowing atmospheric-pressure afterglow, FAPA) coupled to high-resolution (HR) MS was developed and optimized for best performance. The approach is rapid and only requires analytes to be in solution (only a few µL) before application onto thin-layer chromatography (TLC) surfaces, specifically dimethyl (RP2-) and cyano (CN-) modified silica, for surface-assisted (SA) FAPA-HRMS measurements. No chromatographic separation was required, and the TLC plates served only as sample carriers. A broad variety of 19 active pharmaceutical ingredients (APIs) was carefully selected to cover analgesics, anesthetics, antibiotics, antiepileptics, calcium channel blockers, diuretics, expectorants, opioids, peripheral vasodilators, stimulants, and sympathomimetics. Fast screening and identification of APIs was performed by SA-FAPA-HRMS. Typically, the protonated molecular ion ([M+H]+) was the most abundant species, while some compounds (codeine, metamizole, phenoxymethylpenicillin, and torasemide) did show some degree of fragmentation. As a proof-of-principle application, benzocaine was directly detected in saliva samples post-intake of a lozenge. Time-resolved semi-quantitative screening was performed. The limit of detection for benzocaine in saliva was 8 ng/mL (48.4 fmol) using internal standard calibration and CN-HPTLC plates. In addition, direct quantification of artificially spiked saliva was performed with minimal sample preparation. Here, SA-FAPA-HRMS with a CN-HPTLC sample substrate yielded best performance (20.02±0.52 µg/mL, RSD=2.6%, deviation of -1.9% from the theoretical value) compared to RP2-TLC (18.97±1.37 µg/mL, RSD=7.2%, -7.0%), and HPLC-UV (18.51±0.03 µg/mL, RSD=0.2%, -9.3%) results. In conclusion, SA FAPA HRMS is considered attractive for rapid and sustainable analysis of pharmaceuticals with potential in non-invasive patient monitoring.
KW - Mass Spectrometry
KW - Pharmaceuticals
KW - Green Chemistry
KW - Ambient Desorption/Ionization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640718
DO - https://doi.org/10.1039/D5AY01050K
SN - 1759-9660
VL - 17
IS - 18
SP - 7799
EP - 7809
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Niederleithinger, Ernst
A1 - Sein, Sander
A1 - Kervalisvil, Andrei
A1 - Wöstmann, Jens
A1 - Helm, Marek
T1 - Muon tomography - ready for practical application?
N2 - Muon tomography uses naturally occurring nuclear particles to 'X-ray' technical objects. It has applications in security and nuclear safeguards, but not yet in civil engineering. The potential is enormous, as muon tomography could replace traditional X-ray imaging of infrastructure, a method that was popular in the past but has mostly been abandoned due to concerns about radiation safety. In 2020, a report on the first large-scale muon tomography experiment on a reinforced concrete specimen was published. However, robust mobile detectors and faster data acquisition methods are still needed. This is now changing, however. Prototype mobile detectors have been announced or are in development, and data acquisition time has been reduced from weeks to days. This presentation will showcase current developments and focus on a validation experiment at BAM.
T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Izmir, Türkiye
DA - 24.09.2025
KW - Concrete
KW - Muon tomography
KW - Inspection
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642517
DO - https://doi.org/10.58286/31696
SN - 1435-4934
VL - 30
IS - 10
SP - 1
EP - 10
PB - ndt.net
AN - OPUS4-64251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rabe, Ute
A1 - Emge, Julia
A1 - Klein, Samuel
A1 - Oswald, Jan
A1 - Shpakova, Nina
A1 - Stopp, Philipp
A1 - Weingard, Christoph
A1 - Koster, Dirk
A1 - Schönsee, Eric
A1 - Hille, Frank
A1 - Niederleithinger, Ernst
T1 - Development of distributed sensor electronics for energy-efficient and proactive maintenance of buildings
N2 - Permanently installed sensor systems are becoming increasingly important for monitoring critical infrastructure. The research institutes Fraunhofer IZFP and BAM, together with industrial partners and users, are developing a concept for an electronic system consisting of an Edge-Gateway as a central high-performance node and a variable number of Sensor-Edge units that establish the connection between the sensors of the permanent monitoring system and the gateway, which also provides connection to a cloud. A software tool allows identification and localization of sensors and visualization of sensor data. The principle of the system is demonstrated using sensors installed in the road surface to monitor traffic loads as an example. Two test structures, a full-scale laboratory at Fraunhofer IZFP, Saarbrücken, and the “BLEIB” reference structure at BAM, test site technical safety (TTS) Horstwalde, were used to demonstrate the principle and the functioning of the electronic system.
T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Izmir, Türkiye
DA - 24.09.2025
KW - Edge computing
KW - Bridge monitoring
KW - Multi-sensor
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642530
DO - https://doi.org/10.58286/31650
SN - 1435-4934
VL - 30
IS - 10
SP - 1
EP - 3
PB - ndt.net
AN - OPUS4-64253
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Roumia, N.
A1 - Niederleithinger, Ernst
A1 - Mazotti, C.
T1 - Post-tensioned concrete inspection and imaging using 2D and 3D Dry Point Contact ultrasound array
N2 - by the asset owners. Advancements were introduced to the method by distributing numerous shear horizontal Dry Point Contact (DPC) transducers in a uniform way, forming a linear array that allows for immediate two-dimensional imaging of the subsurface using Synthetic Aperture Focusing Technique (SAFT). Recent developments were implemented, allowing for the full potential use of the array by means of three-dimensionaldata acquisition instead of two-dimensional. This work provides a practical comparison between the 2D Linear scanning mode and the newly introduced 3D Matrix scanning mode regarding the tendon duct inspection, grouting quality, and reinforcement localization. Imaging the subsurface was performed through research-oriented software, namely InterSAFT, which allows for 2D and 3D imaging using Linear and Matrix data acquisitions.
T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Izmir, Türkiye
DA - 24.09.2025
KW - Ultrasound
KW - Imaging
KW - Concrete
KW - SAFT
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642551
DO - https://doi.org/10.58286/31690
SN - 1435-4934
VL - 30
IS - 10
SP - 1
EP - 4
PB - ndt.net
AN - OPUS4-64255
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Müller, Bernd R.
A1 - Hentschel, Manfred P.
A1 - Kupsch, Andreas
T1 - Korrektur des Hinterleuchtens an CT-Synchrotrondaten
N2 - In den unterschiedlichsten Methoden der Computertomographie tritt häufig ein diffuses Untergrundsignal in den Einzelprojektionen auf: im Falle der Parallelstrahl-CT mit Synchrotronstrahlung handelt es sich um ein Hinterleuchten durch den Fluoreszenzschirm, der vor der CCD-Kamera angeordnet ist. Dieses Hinterleuchten unterscheidet sich von dem bekannten Nachleuchten (Phosphoreszenz) durch zeitliche Konstanz.
Hier äußert sich das Hinterleuchten als Modulation der projizierten Masse und somit als Funktion der Phase (Projektionswinkel) und des Aspektverhältnisses des Objektes. Der Einfluss des Hinterleuchtens ist abhängig von der Größe des von der Probe abgeschatteten Detektorbereiches und des Objektumfangs (Dynamik). Dies hat u.a. zur Folge, dass Abweichungen vom Absorptionsgesetz auftreten, die umso
stärker ausgeprägt sind, je weniger Detektorfläche das Objekt abdeckt und je stärker das Objekt schwächt. Dabei können Aufhärtungseffekte wegen der monochromatischen Strahlung ausgeschlossen werden.
Mit Referenzmessungen und einem isotropen, homogenen Ansatz, der diese Abweichung als Hinterleuchten beschreibt, lassen sich die auftretenden Fehler deutlich verringern.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Hinterleuchten
KW - Detektor
KW - Fluoreszenzschirm
KW - Synchrotron-Radiographie
KW - Computer-Tomographie
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250038
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (P6)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25003
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Leisegang, T.
A1 - Levin, A.A.
A1 - Kupsch, Andreas
T1 - From the Ritter pile to the aluminum ion battery– Peter Paufler’s academic genealogy
N2 - This article highlights Peter Paufler’s academic genealogy on the occasion of his 80th birthday. We describe the academic background since 1776, which covers 11 generations of scientists: Ritter, Ørsted, Hansteen, Keilhau, Kjerulf, Brøgger, Goldschmidt, Schulze, Paufler, Meyer, and Leisegang. The biographies of these scientists are described in spotlight character and references to scientists such as Dehlinger, Ewald, Glocker, Röntgen, Vegard, Weiss, and Werner are given. A path is drawn that begins in the Romanticism with electrochemistry and the invention of what is probably the first accumulator. It leads through the industrialization and the modern geology, mineralogy, and crystallography to crystal chemistry, metal and crystal physics and eventually returns to electrochemistry and the aluminum-ion accumulator in the era of the energy transition. The academic genealogy exhibits one path of how crystallography develops and specializes over three centuries and how it contributes to the understanding of the genesis of the Earth and the Universe, the exploration of raw materials, and the development of modern materials and products during the industrialization and for the energy transition today. It is particularly characterized by the fields of physics and magnetism, X-ray analysis, and rare earth compounds and has strong links to the scientific landscape of Germany (Freiberg) and Scandinavia, especially Norway (Oslo), as well as to Russia (Moscow, Samara, St. Petersburg). The article aims at contributing to the history of science, especially to the development of crystallography, which is the essential part of the structural science proposed by Peter Paufler.
KW - Academic genealogy
KW - Crystallography
KW - Festschrift
KW - Physics
KW - Structural science
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515254
DO - https://doi.org/10.1515/zkri-2020-0063
SN - 2196-7105
VL - 235
IS - 11
SP - 481
EP - 511
PB - De Gruyter
CY - Berlin
AN - OPUS4-51525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Balko, J.
A1 - Büsse, T.
A1 - Kunkel, J.
A1 - Kupsch, Andreas
A1 - Wieder, Frank
T1 - Schau(m) an, es geht... – Geschäumter Biokunststoff PBS für Leichtbau, Isolierwerkstoffe und Verpackungsmittel
N2 - Flexible, niedrigdichte Schäume aus Biokunststoffen im Extrusionsverfahren herzustellen war bisher industriell noch nicht möglich. Im Verarbeitungstechnikum Biopolymere des Fraunhofer IAP wurde in einem Projekt die Eignung von PBS-basierten Biokunststofftypen für Schaumanwendungen erforscht und weiterentwickelt.
KW - Polymer
KW - Schaum
KW - Polybutylensuccinat (PBS)
KW - Biokunststoff
KW - Computertomographie
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555832
UR - https://www.plastverarbeiter.de/heftarchiv-ausgabendetail/plastverarbeiter-07-08-2022.html
SN - 0032–1338
VL - 73
IS - 7/8
SP - 50
EP - 52
PB - Hüthig GmbH
CY - Heidelberg
AN - OPUS4-55583
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hörmann, Anja F.
A1 - Simon, Miriam
A1 - Brückner, Christoph
A1 - Rogers, Sarah E.
A1 - Porcar, Lionel
A1 - Hoffmann, Ingo
A1 - Gradzielski, Michael
T1 - Line tension controls the spontaneous formation of vesicles
N2 - Mixtures of the zwitterionic surfactant TDMAO and the anionic surfactant LiPFOS spontaneously self-assemble into well defined vesicles. The size of these vesicles is determined by the ratio of bending rigidity and line tension. By partially charging TDMAO, and thereby moving more to a catanionic system, the size of these vesicles can be controlled. Using stopped flow small angle neutron scattering we monitor the kinetics of vesicle formation and obtain their final size. Neutron spin echo spectroscopy allows for an independent measurement of the vesicle’s bending rigidity. Combining this bending rigidity with the radius of newly formed vesicles, which is determined by the ratio of bending rigidity and line tension, we can determine the line tension. We find that it is the line tension that controls the trend in size of the vesicles. In summary, this means that here one has a surfactant mixture that delivers well-defined vesicles, whose size is controlled by the electrostatic interactions of the head groups.
KW - Self-assembly
KW - Small unilamellar vesicles
KW - Small-angle neutron scattering
KW - Line tension
KW - Neutron spin-echo spectroscopy
KW - Stopped-flow
KW - Bending rigidity
KW - Surfactant mixture
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646964
DO - https://doi.org/10.1039/D5SM00600G
SN - 1744-683X
VL - 21
IS - 43
SP - 8360
EP - 8367
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64696
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hilgenfeldt, Verena
A1 - Rübner, Katrin
A1 - Hahn, Andreas
A1 - Steinmetz, Heidrun
T1 - Methodology for Assessing Phosphorus Adsorption Kinetics in Novel Constructed Wetland Materials
N2 - Although various special materials have been studied for their potential for phosphorus removal in constructed wetlands, varying methodologies make direct comparisons of adsorption capacities observed in laboratory experiments difficult. This paper aims to establish a methodology for determining the optimal ratio of phosphate to material mass for different materials and for achieving the necessary contact time for adsorption isotherms. To minimise the number of experiments required, pretests over 24 h should be repeated to determine the phosphate-specific ratios until they show around 60% of the initial concentration. The tested materials included lava sand and expanded sand (ExS), which showed saturating kinetics curves after 24 to 48 h. However, aggregates containing calcium silicate hydrate (CSH) phases (autoclaved aerated concrete AAC, sand–lime brick SLB, and hydrothermal granules HTG) did not show saturating curves, complicating contact time determination. Consequently, adsorption velocity is proposed to identify the phase with the lowest adsorption rate, which is then used as the contact time in adsorption isotherm experiments. Using this method, adsorption times of 48 h were observed for HTG and SLB, while that for AAC was 24 h. This methodology is intended as an initial approach to establish a common basis for researchers investigating novel materials and make the results comparable.
KW - CSH
KW - Phosphate elimination
KW - Material evaluation
KW - Contact time experiments
KW - Methodology development
KW - Filter substrates
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647443
DO - https://doi.org/10.3390/purification1020007
SN - 3042-6197
VL - 1
IS - 2
SP - 1
EP - 20
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-64744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Constanze
A1 - Seher, Julia
A1 - Pniok, Nicole
A1 - Dreisow, Bianca
A1 - Rübner, Katrin
T1 - Formulation and characterization of repair mortars for sandstone with lightweight aggregates made from masonry rubble
N2 - This paper deals with the study of different lime-based repair mortars for the conservation of sandstone objects in the context of monument preservation. New types of lightweight aggregates, which were manufactured from masonry rubble, were used to develop these repair mortars. This allows for recycling of construction and demolition waste while helping to conserve natural resources. As part of this work, the mortars were comprehensively characterised in terms of their chemical, physical, mechanical and hygric properties, such as bulk density, pore structure, strength, water absorption, shrinkage and carbonation. All mortars are lightweight mortars with bulk densities of about 1300 kg/m³. They achieve high porosities of around 50 %. At the same time, the mortars exhibit sufficient compressive strengths ranging from 1.8 to 11.3 MPa. The compressive strength depends on the degree of carbonation of the mortars and increases with sample age. The analysis of the pore structure shows that the mortars mainly contain macropores. The large number of capillary pores, with sizes ranging from 0.1 to 1000 μm, results in a good water absorption behaviour. The evaluation of the results proves that the repair mortars are compatible with Cotta sandstone.
KW - Repair mortar
KW - Lime mortar
KW - Lightweight aggregates
KW - Sandstone
KW - Stone conservation
KW - Recycling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647431
DO - https://doi.org/10.1016/j.conbuildmat.2025.143378
SN - 0950-0618
VL - 494
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-64743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Homann, Christian
A1 - Peeters, Régis
A1 - Mirmajidi, Hana
A1 - Berg, Jessica
A1 - Fay, Michael
A1 - Rodrigues, Lucas Carvalho Veloso
A1 - Radicchi, Eros
A1 - Jain, Akhil
A1 - Speghini, Adolfo
A1 - Hemmer, Eva
T1 - Rapid microwave-assisted synthesis of morphology-controlled luminescent lanthanide-doped Gd2O2S nanostructures
N2 - Gadolinium oxysulfide (Gd2O2S) is an attractive material of demonstrated suitability for a variety of imaging applications, leveraging its magnetic, scintillating, and luminescent properties, particularly when doped with optically active lanthanide ions (Ln3+). For many of these applications, control over size and morphology at the nanoscale is crucial. This study demonstrates the rapid microwave-assisted Synthesis of colloidal Ln2O2S (Ln = Gd and dopants Yb, Er, Tb) nanostructures in as little as 20 min. Structural characterization using X-ray diffraction analysis (XRD), Raman spectroscopy, as well as Transmission electron microscopy (TEM), including elemental mapping via energy dispersive X-ray spectroscopy (EDS), unveiled the key role of elemental sulphur (S8) in the reaction mixtures for materials growth. By systematically varying the Ln-to-S ratio from 1 : 0.5 to 1 : 15, controlled morphologies ranging from triangular nanoplatelets to berry- and flower-like shapes were achieved. Doping with Er3+/Yb3+ endowed the nano-triangles with upconverting and near-infrared emitting properties. Tb3+-doped Gd2O2S exhibited the characteristic green Tb3+ emission under UV excitation, while also showing X-ray excited optical luminescence (XEOL), rendering the material interesting as a potential nano-scintillator.
KW - Upconversion
KW - Microwave-assisted synthesis
KW - Synthesis
KW - Fluorescence
KW - Nano
KW - Particle
KW - NIR
KW - XRD
KW - X-ray fluoressence
KW - Morphology control
KW - Raman
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647907
DO - https://doi.org/10.1039/D5TC01646K
SN - 2050-7526
VL - 13
IS - 35
SP - 18492
EP - 18507
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Talis, Torben
A1 - Pfafferott, Marie
A1 - Esche, Erik
A1 - Repke, Jens‐Uwe
T1 - Recipe‐Free Synthesis of Optimal Operation Trajectories for Batch Processes Based on Process Models
N2 - AbstractBatch processes are usually operated following recipes, which are based on experience and expert knowledge. This ensures feasible and safe operation, because process constraints are indirectly included in the recipe. However, the recipe structure itself constrains the solution space and might exclude other more efficient trajectories. Therefore, the hidden constraints are explicitly formulated, and the arising optimization problem is solved without using prior knowledge in the form of recipes. Case studies are performed on rigorous models of a batch reactor and a batch distillation column. It is demonstrated that the optimization problem formulated as a smoothed dynamic nonlinear programming problem outperforms a mixed‐integer formulation. Finally, a multi‐objective case is investigated that strongly outperforms a recipe‐based benchmark.
KW - Batch process operation
KW - Control vector parameterization
KW - Nonlinear optimization
KW - Sequential optimization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642012
DO - https://doi.org/10.1002/cite.70029
SN - 0009-286X
SP - 1
EP - 10
PB - Wiley-VHC
CY - Weinheim
AN - OPUS4-64201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, Heike
A1 - Zahedi-Azad, Setareh
A1 - Ernst, Owen C.
A1 - Lucaßen, Jan
A1 - Mann, Guido
A1 - Bonse, Jörn
A1 - Boeck, Torsten
A1 - Martin, Jens
A1 - Schmid, Martina
A1 - Krüger, Jörg
T1 - Chemical vapor deposition of indium precursors for solar microabsorbers using continuous laser radiation
BT - A, Materials science & processing
N2 - Localized deposition of indium on an amorphous glass surface covered with a thin molybdenum layer is demonstrated utilizing laser-assisted chemical vapor deposition. A continuous-wave laser causes a temperature rise on the molybdenum layer resulting in the selective aggregation of liquid and ultimately crystalline structures of indium. The formation sites of the indium are determined by the decomposition of gaseous trimethylindium. The deposited indium islands can serve as precursors and could be further processed into compound semiconductors like CuInSe2 for micro-concentrator solar cells. The experimental investigations were supported by theoretical simulations of the laser heating process to calculate the local temperature distribution on the surface of the molybdenum-covered glass substrate.
KW - Laser-assisted Chemical Vapor Deposition
KW - CW Laser
KW - Indium Islands
KW - Micro-concentrator Solar Cell
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641069
DO - https://doi.org/10.1007/s00339-025-08895-z
SN - 0947-8396
VL - 131
SP - 1
EP - 10
PB - Springer
CY - Berlin ; Heidelberg [u.a.]
AN - OPUS4-64106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, Alan
A1 - Moschetti, Michael
A1 - Miskovic, David
A1 - Wei, Tao
A1 - Ionescu, Mihail
A1 - Wang, Zhiyang
A1 - Palmer, Tim
A1 - Bhattacharyya, Dhriti
A1 - He, Peidong
A1 - Li, Xiaopeng
A1 - Gludovatz, Bernd
A1 - Ferry, Michael
T1 - Improved irradiation resistance of a low activation refractory medium entropy alloy, VCrFeW0.2, for fusion applications demonstrated by micro-tensile testing
N2 - An, as cast, VCrFeW0.2 refractory medium entropy alloy (RMEA) was designed for fusion reactor divertor applications, focusing on reduced cost, low activation and compositional stability (low transmutation rates). The as-cast alloy was irradiated to a fluence of 5.6 × 10^17 ions/cm^2 at room temperature with 5 MeV helium ions whose energy have been uniformly attenuated to 0.4 MeV and 5 MeV via energy degradation device prior to sample irradiation. Pre and post irradiation, its mechanical properties were evaluated micro-tensile testing. Prior to irradiation, the VCrFeW0.2 alloy demonstrated good strength and ductility, with a yield strength of 1464 MPa and strain to UTS (\sigma_UTS) of 4.6 %, maintaining comparable strength to pure tungsten (1403 MPa) but with greater strain to UTS (1.3 %). Post irradiation, the VCrFeW0.2 alloy exhibited remarkable damage resistance; its strength increased by only ∼160 MPa, and it retained strain to UTS with a \sigma_UTS of 2.9 %. It performed better than pure tungsten tested under identical irradiation conditions where there was ∼1800 MPa increase in yield strength and a complete loss of plasticity. The micro-tensile results were supported by nanoindentation tests and Vickers hardness testing was also undertaken to show the yield strength values are representative of macro scale, bulk behavior. TEM and comparison with existing literature on RMEA/RHEA are presented here to understand the reason for difference in performance between VCrFeW0.2 alloy and pure tungsten.
KW - Refractory medium entropy alloys
KW - Fusion reactor materials
KW - Irradiation resistance
KW - Micro-tensile testing
KW - Helium ion damage
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645322
DO - https://doi.org/10.1016/j.ijrmhm.2025.107481
SN - 0263-4368
VL - 134
SP - 1
EP - 16
PB - Elsevier Ltd.
CY - Netherlands
AN - OPUS4-64532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ukrainczyk, Neven
A1 - Bernard, Thomas
A1 - Babaahmadi, Arezou
A1 - Huang, Liming
A1 - Zausinger, Christoph
A1 - Soive, Anthony
A1 - Bonnet, Stéphanie
A1 - Georget, Fabien
A1 - Mrak, Maruša
A1 - Dolenec, Sabina
A1 - Völker, Tobias
A1 - Suraneni, Prannoy
A1 - Wilson, William
T1 - Test methods for chloride diffusivity of blended cement pastes: a review by RILEM TC 298-EBD
N2 - The use of supplementary cementitious materials (SCM) is an important part of the roadmap for reducing CO2 emissions and extending the service life of reinforced concrete structures. To accelerate the adoption of SCMs, the RILEM Technical Committee 298-EBD evaluates scaled-down cement paste test methods to assess the effect of SCM on resistance to chloride and sulfate ingress and reactivity, which are critical to concrete durability. This review focuses on methods for measuring chloride diffusivity and is divided into four sections: diffusivity models and parameters, diffusion test methods (including NMR and chloride measurements), migration test methods and implications for future research. Key insights highlight the complexities of multi-species ionic and molecular diffusion/migration, including various binding interactions, and compares the different measurement methodologies. The review also addresses the test scale and aggregate effects, noting the pros and cons of testing at the paste, mortar, and concrete scales. The review underscores the need for further investigation into testing protocols and the influence of SCM on chloride diffusion, emphasizing that comprehensive testing across different scales provides complementary information for assessing durability performance.
KW - Chloride ingress
KW - Diffusion tests
KW - Migration test
KW - Cement paste
KW - Concrete
KW - Supplementary cementitious materials (SCM)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645889
DO - https://doi.org/10.1617/s11527-025-02809-4
SN - 1359-5997
VL - 58
IS - 10
SP - 1
EP - 35
PB - Springer Science and Business Media LLC
AN - OPUS4-64588
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bauer, L.J.
A1 - Wieder, Frank
A1 - Truong, V.
A1 - Förste, F.
A1 - Wagener, Y.
A1 - Jonas, A.
A1 - Praetz, S:
A1 - Schlesiger, C.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Kanngießer, B.
A1 - Zaslansky, P.
A1 - Mantouvalou, I.
T1 - Absorption Correction for 3D Elemental Distributions of Dental Composite Materials Using Laboratory Confocal Micro-X-ray Fluorescence Spectroscopy
N2 - Confocal micro-X-ray fluorescence (micro-XRF) spectroscopy facilitates three-dimensional (3D) elemental imaging of heterogeneous samples in the micrometer range. Laboratory setups using X-ray tube excitation render the method accessible for diverse research fields but interpretation of results and quantification remain challenging. The attenuation of X-rays in composites depends on the photon energy as well as on the composition and density of the material. For confocal micro-XRF, attenuation severely impacts elemental distribution information, as the signal from deeper layers is distorted by superficial layers. Absorption correction and quantification of fluorescence measurements in heterogeneous composite samples have so far not been reported. Here, an absorption correction approach for confocal micro-XRF combining density information from microcomputed tomography (micro-CT) data with laboratory X-ray absorption spectroscopy (XAS) and synchrotron transmission measurements is presented. The energy dependency of the probing volume is considered during the correction. The methodology is demonstrated on a model composite sample consisting of a bovine tooth with a clinically used restoration material.
KW - Micro X-ray fluorescence spectroscopy
KW - Dental composite materials
KW - Computed tomography
KW - Absorption correction
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601630
DO - https://doi.org/10.1021/acs.analchem.4c00116
SN - 0003-2700
SN - 1520-6882
VL - 96
IS - 21
SP - 8441
EP - 8449
PB - American Chemical Society Publications
CY - Washington, DC
AN - OPUS4-60163
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xin, L.
A1 - Mika, J.
A1 - Horbert, V.
A1 - Bischoff, S.
A1 - Schubert, H.
A1 - Borowski, J.
A1 - Maenz, S.
A1 - Huber, R.
A1 - Sachse, A.
A1 - Illerhaus, Bernhard
A1 - Kinne, R. W.
T1 - Systematic postoperative assessment of a minimally-invasive sheep model for the treatment of osteochondral defects
N2 - To assess the clinical course of a sheep stifle joint model for osteochondral (OC) defects, medial femoral condyles (MFC) were exposed without patella luxation using medial parapatellar skin (3–4 cm) and deep incisions (2–3 cm). Two defects (7 mm diameter; 10 mm depth; OC punch) were left empty or refilled with osteochondral autologous transplantation cylinders (OATS) and explanted after six weeks. Incision-to-suture time, anesthesia time, and postoperative wound or impairment scores were compared to those in sham-operated animals. Implant performance was assessed by X-ray, micro-computed tomography, histology, and immunohistology (collagens 1, 2; aggrecan). There were no surgery-related infections or patellar luxations. Operation, anesthesia, and time to complete stand were short (0.5, 1.4, and 1.5 h, respectively). The wound trauma score was low (0.4 of maximally 4; day 7). Empty-defect and OATS animals reached an impairment score of 0 significantly later than sham animals (7.4 and 4.0 days, respectively, versus 1.5 days). Empty defects showed incomplete healing and dedifferentiation/heterotopic differentiation; OATS-filled defects displayed advanced bone healing with remaining cartilage gaps and orthotopic expression of bone and cartilage markers. Minimally-invasive, medial parapatellar surgery of OC defects on the sheep MFC allows rapid and low-trauma recovery and appears well-suited for implant testing.
KW - Osteochondral stifle joint defect
KW - Sheep animal model
KW - Minimally-invasive parapatellar approach
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520180
DO - https://doi.org/10.3390/life10120332
SN - 2075-1729
VL - 10
IS - 12
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-52018
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Soares, A.P.
A1 - Kupsch, Andreas
A1 - Baum, D.
A1 - Hesse, B.
A1 - Zaslansky, P.
T1 - Untersuchung der Integrität von glasfaserverstärkten Zahnstiften mittels Synchrotron-Röntgenrefraktion
N2 - Die Integrität der Verstärkungsfasern in Komposit-Zahnstiften ist entscheidend für die Biegefestigkeit und die langfristige Haftung am Zement in den Wurzelkanälen. Es wurde vermutet, dass die Integrität von glasfaserverstärkten Zahnstiften durch das Beschleifen während der zahnmedizinischen Behandlung beeinträchtigt wird. Eine Beschädigung der Fasern führt zu einer erheblichen strukturellen Schwächung über den gesamten Stiftdurchmesser. Glasfragmente, die durch den Kontakt mit dem Zahnbohrer entstehen, können sich vom Stift lösen und die Haftfähigkeit erheblich verringern. Mit Hilfe hochauflösender Synchrotron-Röntgen-Refraktions-Radiographie (SXRR) konnte das Ausmaß der Schäden zuverlässig identifiziert und charakterisiert werden.
Dazu wurden die Glasfaserstifte sowohl im Herstellungszustand als auch nach der Bearbeitung mit einem Diamantbohrer untersucht. Die Datensätze wurden zur Visualisierung und Quantifizierung der morphologischen Charakteristika intakter und durch das Beschleifen beschädigter Regionen analysiert. Sie zeigen Schäden im bearbeiteten Bereich (z. B. Brüche, Splitter und Risse) sowie herstellungsbedingte Inhomogenitäten der Fasern mit einer signifikanten Zunahme der inneren Oberflächen in Probenregionen, die durch das Beschleifen beschädigt wurden.
T2 - DGZfP Jahrestagung 2022
CY - Kassel, Germany
DA - 23.05.2022
KW - Röntgen-Refraktion
KW - Verbundwerkstoffe
KW - Zahnstifte
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549231
SP - 1
EP - 7
AN - OPUS4-54923
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Nielow, D.
A1 - Hickmann, Stefan
A1 - Kupsch, Andreas
A1 - Gaal, Mate
A1 - Redmer, Bernhard
A1 - Krankenhagen, Rainer
T1 - Sandwich-Schalenstrukturen in situ charakterisiert mit Thermographie und Felddehnungsmessungen
N2 - An der BAM wurde ein Schalenprüfstand entwickelt, mit dem typische Sandwichschalenstrukturen unter simulierter Betriebsbeanspruchung belastet werden können. Im mechanischen Ermüdungsversuch wurden in situ die Entstehung von Schäden in Schalenprüfkörpern mit Test-Imperfektionen mittels der passiven Thermographie und Felddehnungsmessungen verfolgt. Damit konnten der Zeitpunkt, der Schadensursprung und der Schadensfortschritt zerstörungsfrei bestimmt werden. Zudem wurden vergleichend Schalenprüfkörper mit Luftultraschall und der Röntgen-Laminographie untersucht. Im Rahmen eines BMWi-Forschungsvorhabens wurden die Schädigungsmechanismen evaluiert und Empfehlungen für die Praxis der Fertigung von Rotorblättern abgeleitet. In diesem Beitrag wird sich auf die Darstellung der ZfP-Verfahren und der ZfP-Ergebnisse konzentriert.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Windkraft
KW - Rotorblatt
KW - Schalenprüfstand
KW - Thermographie
KW - Laminographie
KW - Luftultraschall
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469395
VL - 166
SP - 1
EP - 11
AN - OPUS4-46939
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, Olivia
A1 - Westphalen, Tanja
A1 - Kaminski, Katja
A1 - Kluge, Stephanie
A1 - Bücker, Michael
A1 - Piechotta, Christian
T1 - Evaluation and Validation of an Accelerated Weathering Procedure to Characterise the Release of Bisphenol A from Polycarbonate Under Exposure to Simulated Environmental Conditions
N2 - Bisphenol A (BPA) has been listed as a substance of very high concern (SVHC) due to its endocrine-disrupting properties according to REACH in 2017. European competent authorities have prepared a REACH restriction proposal to reduce BPA levels in the environment. The proposed limit for the concentration of free BPA and other bisphenols in articles is 10 mg kg−1. If exceeded, migration testing can demonstrate that no more than 0.04 mg L−1 is released from the product or material over its lifetime. German authorities are drafting a new restriction proposal after the original was temporarily withdrawn. The residual and migration limits mentioned above were key requirements from the previous restriction proposal. Numerous national and international standards exist for assessing how environmental factors affect the physical and chemical properties of products and materials—such as notch impact strength and tensile strength—but these standards do not cover the release of pollutants. A standardised procedure that covers all aspects of artificial weathering and monitors the subsequent release of pollutants is necessary, especially in the context of the regulation of these substances. An accelerated weathering procedure was established for non-protected samples. This material was not intended for outdoor applications. The testing procedure applied a typical weathering scenario that represents Central European climate conditions. The procedure was validated and applied to samples under distinct quality assurance aspects. Released BPA is quantified via an organic isotope dilution LC-MS/MS method. In parallel, identical samples were weathered outdoors on a weathering rack. Haze and yellowness index are measured to compare outdoor and weathering chamber results.
KW - Artificial weathering
KW - Polycarbonate
KW - Bisphenol A
KW - Simulated environmental conditions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645020
DO - https://doi.org/10.3390/app151910361
SN - 2076-3417
VL - 15
IS - 19
SP - 1
EP - 15
PB - MDPI AG
AN - OPUS4-64502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Tim
A1 - Huber, Norbert
T1 - Designing microcompression experiments for nanoporous metals via computational plasticity
N2 - Micropillar compression testing is essential for understanding bulk metal plasticity at small scales and has emerged as a key technique for evaluating nanoporous metals like nanoporous gold (NPG). To support experimental design, we present a computational plasticity study on single crystal NPG micropillars, systematically examining four extrinsic factors: pillar height-to-diameter ratio, taper angle, friction coefficient, and misalignment angle. The study reveals that NPG exhibits similar trends to its bulk counterpart but is less prone to post-yield buckling in unstable crystal orientations. For optimal NPG pillar stability, an aspect ratio of is recommended and a moderate taper angle to prevent artificial stiffening and yielding. Even minimal friction enhances stability, while buckling is mainly governed by misalignment, requiring to also avoid underestimating the elastic modulus.
KW - Nanoporous gold
KW - Microcompression
KW - Plasticity
KW - Finite element method
KW - Micromechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645317
DO - https://doi.org/10.1016/j.matdes.2025.114550
SN - 0264-1275
VL - 258
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-64531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Araujo Abilio, André
A1 - Wolodko, John D.
A1 - Eckert, Richard B.
A1 - Skovhus, Torben L.
T1 - Development of an expert system for assessing failures in oil and gas pipelines due to microbiologically influenced corrosion (MIC)
N2 - This study highlights the modeling of an expert system for the classification of internal microbiologically influenced corrosion (MIC) failures related to pipelines in the upstream oil and gas industry. The model is based on artificial neural networks (ANNs) and involves the participation of 15 MIC experts. Each expert evaluated a number of model case studies ranging from MIC- to non-MIC-driven upstream pipeline failures. The model accounts for variations in microbiological testing methods, microbiological sample types, and degradation morphology, among other variables. It also accounts for missing datasets, which is commonly the case in actual failure assessments. The outcome is an expert system model whose outputs are classes (classification ANN) which comprises MIC potential and data confidence. The performances of two approaches are contrasted in this study. One classifies the output in 5 classes, a 5-output classification (5OC) model; the other in 3 classes, a 3-output classification (3OC) model. The 5OC model had an accuracy of 62.0% while the simpler 3OC model had a better accuracy of 74.8%. This modelling exercise has demonstrated that knowledge from experts can be captured in a reasonably effective model to screen for possible MIC failures. It is hoped that this study not only may contribute to a better understanding of the prevalence of MIC in the oil and gas sector, but also may highlight the key areas necessary to improve the diagnosis of MIC failures in the future.
KW - Corrosion engineering
KW - Oil and gas pipelines
KW - Carbon steel
KW - Artificial neural networks (ANNs)
KW - Failure analysis
KW - Microbiologically influenced corrosion (MIC)
KW - Expert systems
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632084
DO - https://doi.org/10.1016/j.engfailanal.2024.108426
SN - 1350-6307
VL - 163
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-63208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirwald, Johannes
A1 - Khalighi, Sadaf
A1 - Varveri, Aikaterini
A1 - Hofko, Bernhard
A1 - Adwani, Dheeraj
A1 - Cannone-Falchetto, Augusto
A1 - Elwardany, Michael
A1 - Kleiziené, Rita
A1 - Konieczna, Katarzyna
A1 - Maliszewski, Maciej
A1 - Mouillet, Virginie
A1 - Nahar, Sayeda
A1 - Piérard, Nathalie
A1 - Pipintakos, Georgios
A1 - Porot, Laurent
A1 - Primerano, Kristina
A1 - Sharma, Aditi
A1 - Tavassoti, Pejoohan
A1 - Weigel, Sandra
A1 - Wetekam, Jens
A1 - Zhu, Jiqing
T1 - Evaluating the reproducibility and consistency of different sample preparation techniques used for ATR-FTIR spectroscopy from the RILEM 295-FBB TG1 round robin test
N2 - Attenuated Total Reflection Fourier Transform Infrared spectroscopy has become a popular spectroscopic technique in bituminous binder analysis. However, comparable results are not obtainable yet due to differences in devices, measurement routines, sample preparation procedures, and spectral evaluation. Thus, the Task Group 1 of the RILEM TC 295-FBB: “Fingerprinting bituminous binders using physicochemical analysis” focuses on bringing this method towards pre-standardization. This study evaluates the reproducibility and consistency from round robin test, where 21 participating laboratories performed six different preparation techniques on three different binders in an unaged, short-term, and long-term aged state. A total of 6461 spectra were recorded and evaluated for their mean, standard deviation and coefficient of variation (CV) in the spectral region between 1800 and 600 cm−1. The results show that the solid sample preparation methods provide excellent reproducibility, with a coefficient of variation below 2%. Only the solvent method showed a higher coefficient of variation at 7.18%. Outliers with a high CV were detected and categorized into two groups: one where only one of the four samples differed and the other where all 16 spectra showed slight scattering in the overall absorption. The consistency of the method is significantly influenced by the accuracy of sample preparation, which is crucial for minimizing differences in slope, baseline, and noise in the spectra. These findings show the excellent reproducibility of these sample preparation methods and will be further examined to establish universal indices for evaluating effects such as ageing, bringing the method closer towards standardization.
KW - Bitumen
KW - FTIR-Spektroskopie
KW - Reproducibility
KW - Round robin test
KW - Material handling
KW - preparation routine
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645386
DO - https://doi.org/10.1617/s11527-025-02755-1
SN - 1359-5997
VL - 58
IS - 8
SP - 1
EP - 21
PB - Springer Science and Business Media LLC
AN - OPUS4-64538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Yong
A1 - Hu, Kaixiong
A1 - Lilleodden, Erica T.
A1 - Huber, Norbert
T1 - Datasets for structural and mechanical properties of nanoporous networks from FIB reconstruction
N2 - This dataset paper presents a comprehensive archive of 3D tomographic reconstruction image files, volume mesh files for finite element simulations, and tabulated structural and mechanical properties data of nanoporous gold structures. The base material is nanoporous gold, fabricated using a dealloying process, with a solid fraction of approximately 0.30. The NPG samples with ligament sizes ranging from 20 nm to 400 nm were prepared by dealloying and by controlling the thermal annealing process. The original data consist of tomographic TIFF files acquired through Focused Ion Beam/Scanning Electron Microscopy (FIB/SEM) 3D reconstruction, as detailed in Philosophical Magazine 2016 96 (32-34), 3322-3335. At each ligament size, six sets of 3D tomographic images were obtained from different regions of the same sample to ensure representative data. New simulations and analyses were conducted based on the 3D image data. The resulting structural and mechanical property data of nanoporous gold are reported for the first time in this dataset paper. Volume meshing of the 3D reconstructed data was performed using Simpleware software. Structural parameters, including surface area, solid volume, and solid volume fraction of the nanoporous network, were extracted from the meshed volumes. Structural connectivity was assessed from the 3D microstructures. The meshed volumes were then used as input for finite element simulations performed in Abaqus to evaluate mechanical responses under uniaxial compression along all three principal axes respectively. From the resulting stress–strain curves, the Young’s modulus and yield strength of each structure were determined. Both elastic and plastic Poisson’s ratios were analyzed from true strain increments. This dataset includes the 3D tomographic images, corresponding volume mesh files, mechanical behavior data and tables summarizing the structural and mechanical properties. The archived data serve as a database for nanoporous network materials and can be reused for numerical simulations, additive manufacturing, and machine learning applications within the materials science community. All files are openly accessible via the TORE repository at https://doi.org/10.15480/882.15230
KW - Nanoporous gold
KW - Dealloying
KW - FIB/SEM tomography
KW - Finite element
KW - Volume mesh
KW - Young’s modulus
KW - Yield stress
KW - Poisson’s ratio
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645330
DO - https://doi.org/10.1016/j.dib.2025.112152
SN - 2352-3409
VL - 63
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-64533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Malefioudaki, Mariella
A1 - Misra, Archismita
A1 - Sbeity, Nadja
A1 - Zueco-Vincelle, Juan
A1 - Laguna-Bercero, Miguel A.
A1 - Koerdt, Andrea
A1 - Martín-Rapún, Rafael
A1 - Mitchell, Scott G.
T1 - Multifunctional polyoxomolybdate ionic liquid coatings for mitigating microbiologically influenced corrosion
N2 - Corrosion of metals and other materials in marine environments poses significant economic, operational, safety, and environmental challenges across the oil and gas industry, the renewable energy sector, and maritime infrastructure. Microbiologically influenced corrosion (MIC) accounts for a substantial portion of this corrosion, with sulfate-reducing bacteria (SRB) and methanogenic archaea (MA) being key contributors. Conventional methods such as cathodic polarization have proven insufficient in mitigating the colonization of corrosive microbial communities in real marine environments, requiring the development of alternative, broad-spectrum antimicrobial strategies to prevent such biofilm formation. Recently, molybdate has emerged as a potential alternative to traditional biocides and nitrate. Our hypothesis is polyoxometalate-ionic liquids (POM-ILs), which exhibit antimicrobial and anticorrosion properties, could have a broader spectrum of antimicrobial activity than demonstrated until now and could be capable of shielding and protecting sensitive metal surfaces from the extreme acidic environments produced by MIC microorganisms. Here we show how two prototype polyoxomolybdate-based POM-ILs, [(CH3(CH2)6)4N]2[Mo6O19] and [(CH3(CH2)6)4N]4[Mo8O26], demonstrated antimicrobial activity at microgram per millilitre concentrations, prevented biofilm formation on metal surfaces, and provided resistance to corrosive acidic environments. Furthermore, impedance measurements were commensurate with electron microscopy studies showing that POM-IL-coated brass coupons withstood extremely corrosive environments. These proof-of-concept results demonstrate how multi-functional POM-IL coatings represent promising MIC mitigation solutions by providing a hydrophobic acid-resistant and biocidal protective layer that prevents biocolonisation and acidic corrosion by MIC microorganisms.
KW - Polyoxometalates
KW - Ionic liquid
KW - Microbiologically influenced corrosion
KW - Corrosion
KW - Heritage preservation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631951
DO - https://doi.org/10.1039/d5mh00373c
SN - 2051-6347
VL - 12
IS - 13
SP - 4648
EP - 4661
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-63195
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erdmann, Maren
A1 - Kleinbub, Sherin
A1 - Wachtendorf, Volker
A1 - Schütter, Jan David
A1 - Niebergall, Ute
A1 - Böhning, Martin
A1 - Koerdt, Andrea
T1 - Photo-oxidation of PE-HD affecting polymer/fuel interaction and bacterial attachment
N2 - In the present study, a simple approach was used to investigate the effect of UV-exposure on two high density Polyethylene materials (PE-HD), commonly used for storage tanks, on fuel sorption behavior and colonization by microorganisms. The aim was to investigate whether the sorption behavior of the fuels (diesel/biodiesel) and the colonization by microorganisms, frequently occurring in the fuel, is affected and may lead to undesirable or safety-relevant material changes. We showed that the UV-irradiation leads to significant changes of the sorption behavior due to chemi-crystallization and crosslinking. The fuel Sorption is affected by the UV-induced formation of polar carbonyl and hydroxyl groups predominantly occurring at the surface. With respect to microbial colonization behavior for Bacillus subtilis and Pseudomonas aeruginosa, isolated from a contaminated diesel sample, differences of the initial adhesion could be shown depending on the initial type of polyethylene as well as on the degree of UV-induced degradation.
KW - High density polyethylene
KW - Bacterial attachment
KW - UV-irradiation
KW - Fuel sorption
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510001
DO - https://doi.org/10.1038/s41529-020-0122-1
VL - 4
IS - 1
SP - Article number: 18
PB - Nature Partner Journals
AN - OPUS4-51000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - George, Joyal K.
A1 - von Wangenheim, Kristian
A1 - Kaplan, Felix
A1 - Schneider, Ronald
A1 - Hindersmann, Iris
ED - Lienhart, Werner
ED - Krüger, Markus
T1 - Monitoring of civil engineering structures - current and future use cases
N2 - Monitoring represents an effective approach for addressing the diverse challenges associated with the maintenance of civil engineering structures. It contributes to improving both the availability and safety of these structures. By increasing the amount of information available about the structure, monitoring supports better-informed decisions regarding its preservation. Due to the complexity of monitoring applications, specific use cases are outlined. A key advantage of these use cases is that new technologies can be tested within well-defined and limited scopes. The use cases monitoring of known, localized damage, monitoring of known deficits identified through reassessment or resulting from outdated design procedures and monitoring aimed at assessing traffic loads and their effects currently account for the majority of implemented monitoring measures. Their practical implementation is demonstrated through case studies from the Brandenburg State Road Authority. Additional use cases, such as monitoring to support structural inspections and monitoring of major structures, such as large viaducts, are gaining importance, with initial practical examples already present in Europe. Future applications reveal potential for expanded use, particularly in the context of monitoring to support predictive lifecycle management. This will become increasingly important in the implementation of digital twins, as announced in the national BIM master plan. Furthermore the concept of a Birth Certificate is intended to establish a reference state of the structure prior to commissioning, which can then be used for comparison with future measurements over time. The integration and interaction of these individual use cases pave the way for the implementation of digital twins.
T2 - 13th International Conference on Structural Health Monitoring of Intelligent Infrastructure
CY - Graz, Austria
DA - 01.09.2025
KW - Structural Health Monitoring
KW - Use Cases
KW - Bridges
KW - Digital Twin
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644422
DO - https://doi.org/10.3217/978-3-99161-057-1-033
SP - 203
EP - 208
PB - Verlag der Technischen Universität Graz
CY - Graz
AN - OPUS4-64442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baller, Johannes
A1 - Hilger, André
A1 - Qi, Naiyu
A1 - Morini, Chiara
A1 - Cornelio, Andrea
A1 - Remhof, Arndt
A1 - Osenberg, Markus
A1 - Manke, Ingo
A1 - Moosmann, Julian
A1 - Beckmann, Felix
A1 - Graeber, Gustav
T1 - Wetting Interactions Between Porous Carbon Hosts and Liquid Sodium‐Potassium Alloys Toward Their Use in Negative Electrodes of Alkali‐Metal Batteries
N2 - Batteries with liquid alkali‐metal negative electrodes offer a route to compact, high‐performance energy storage. Innovation in alkali‐metal management, i.e., controlled storage, release and transport of liquid alkali metal, can enable simpler and cheaper cell designs. Porous carbons have emerged as potential host materials for liquid alkali metals. Here, X‐ray computed tomography is used to study the wetting interactions between porous carbon hosts and liquid sodium‐potassium alloy (NaK) as a function of carbon host morphology and surface functionalization. While as‐received carbon samples show no affinity toward NaK, heat‐treated carbon is spontaneously infiltrated with NaK filling almost the entire pore volume. It is explored how forced wetting partially fills pores of NaK‐repellant hosts, showing large differences in pore filling based on the average pore size of the host material. In electrochemical discharge experiments, it is shown that both as‐received and heat‐treated carbon felt enable high areal capacities beyond 40 mAh cm−2. However, the heat‐treated carbon shows ten times lower overpotential. Finally, it is demonstrated how heat‐treated carbon felt can enable capillary transport of NaK. In summary, this study elucidates important aspects of the interactions between liquid alkali metals and porous carbon hosts, generating insights into possible applications in liquid alkali‐metal batteries.
KW - Battery
KW - Solid electrolyte
KW - Sodium
KW - Wetting
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644663
DO - https://doi.org/10.1002/adfm.202523169
SN - 1616-301X
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-64466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koerdt, Andrea
T1 - Mikrobiell beeinflusste Korrosion – die Testungsart entscheidet
N2 - In diesem kurzem Artikel wird die neue Testungsart druch Hi-Tension vorgestellt. Der Hauptfokus liegt dabei auf die Umweltsimulations-Säule, mit deren Hilfe die bisher bekannten Korrosionsraten von methanogenen Archaea signifikant erhöht wurden.
KW - Hi-Tension
KW - MIC
KW - Methanogene
KW - Umweltsimulation
PY - 2021
DO - https://doi.org/10.1007/s12268-021-1507-7
VL - 27
SP - 100
EP - 100
PB - BIOspektrum Springer
AN - OPUS4-52193
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koerdt, Andrea
A1 - Gerengi, Husnu
A1 - Kaya, Ertugrul
A1 - M. Solomon, Moses
A1 - Snape, Matthew
T1 - Advances in the Mitigation of Microbiologically Influenced Concrete Corrosion: A Snapshot
N2 - Concrete, a versatile construction material, faces pervasive deterioration due to microbiologically influenced corrosion (MIC) in various applications, including sewer systems, marine engineering, and buildings. MIC is initiated by microbial activities such as involving sulfate-reducing bacteria (SRB), sulfur-oxidizing bacteria (SOB), etc., producing corrosive substances like sulfuric acid. This process significantly impacts structures, causing economic losses and environmental concerns. Despite over a century of research, MIC remains a debated issue, lacking standardized assessment methods. Microorganisms contribute to concrete degradation through physical and chemical means. In the oil and gas industry, SRB and SOB activities may adversely affect concrete in offshore platforms. MIC challenges also arise in cooling water systems and civil infrastructures, impacting concrete surfaces. Sewer systems experience biogenic corrosion, primarily driven by SRB activities, leading to concrete deterioration. Mitigation traditionally involves the use of biocides and surface coatings, but their long-term effectiveness and environmental impact are questionable. Nowadays, it is important to design more eco-friendly mitigation products. The microbial-influenced carbonate precipitation is one of the green techniques and involves incorporating beneficial bacteria with antibacterial activity into cementitious materials to prevent the growth and the formation of a community that contains species that are pathogenic or may be responsible for MIC. These innovative strategies present promising avenues for addressing MIC challenges and preserving the integrity of concrete structures. This review provides a snapshot of the MIC in various areas and mitigation measures, excluding underlying mechanisms and broader influencing factors.
KW - MIC
KW - Corrosion
KW - Concrete
KW - Environment
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-619218
DO - https://doi.org/10.3390/ma17235846
VL - 17
IS - 23
SP - 1
EP - 19
PB - MDPI
AN - OPUS4-61921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yao, J.
A1 - Jiang, T.
A1 - Ji, Y.
A1 - An-Stepec, Biwen Annie
A1 - Koerdt, Andrea
A1 - Cai, Z.
A1 - Dong, C.
A1 - Ge, Y.
A1 - Qi, Z.
T1 - Water-Fueled Autocatalytic Bactericidal Pathway based on e-Fenton-Like Reactions Triggered by Galvanic Corrosion and Extracellular Electron Transfer
N2 - Water is generally considered to be an undesirable substance in fuel system, which may lead to microbial contamination. The antibacterial strategies that can turn water into things of value with high disinfection efficacy have been urgently needed for fuel system. Here, we reveal a water-fueled autocatalytic bactericidal pathway comprised by bi-metal micro-electrode system, which can spontaneously produce reactive oxygen species (mainly H2O2 and O2•–) by the electron Fenton-like reaction in water medium without external energy., The respiratory chain component of bacteria and the galvanic corrosion on the coated metals were two electron sources in the system. The specific model of Ag-Ru water-fueled autocatalytic (WFA) microelectrode particles presents extremely high disinfection efficiency (>99.9999%) in less than one hour for three aerobic bacteria (Escherichia coli, Pseudomonas aeruginosa and Bacillus subtilis) in LB media and high disinfection efficiency for the anaerobic bacteria (Desulfovibrio alaskensis) in Postgate E media without natural light irradiation. Overall, the novel WFA Ag-Ru antibacterial material explored in this study has a high potential for sterilizing applications in fuel system and this work provides the potential for the development of non-chemical and water-based antibacterial materials, such as WFA Ag-Ru antibacterial coating on stainless steel.
KW - Fenton-like reaction
KW - Reactive oxygen species
KW - Disinfection Fuel
KW - Silver
KW - Ruthenium
KW - MIC
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555186
DO - https://doi.org/10.1016/j.jhazmat.2022.129730
SN - 0304-3894
VL - 440
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-55518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dopffel, N.
A1 - An Stepec, Biwen Annie
A1 - de Rezende, J.
A1 - Machado de Sousa, D.
A1 - Koerdt, Andrea
T1 - Microbiology of Underground Hydrogen Storage
N2 - Climate change is becoming one of the greatest challenges facing our society, particularly due to the continued use of fossil fuels. The steadily increasing demand for energy and the continuously growing world population will further intensify these challenges. The development of renewable energies is therefore of central importance. The 2020 EU Energy Roadmap aims to increase the share of renewable energies (gross energy consumption) to 55% by 2050.
Hydrogen (H2) has the highest potential to become the primary renewable energy source. It is envisioned that by 2050 up to 24% of the total energy demand of Europe is to be ensured by H2. However, a decisive disadvantage of the climate friendly alternatives is the massive containment demand, which needs to be highly secure, cost efficient and easily extractable.
Underground geological formations (UGF) represent a seemingly optimal alternative to meet the rapidly increasing storage demand. In this context, many studies are currently underway to determine the feasibility and risks of UGF. However, little or no consideration is being given to microbiology. Therefore, in this Research Topic we will focus on achieving a greater understanding of the impact microorganisms exert on UGF, with a particular emphasis on interdisciplinary studies.
As many subsurface microbial communities can use H2 as an electron donor, production of seemingly undesirable metabolic byproducts, such as hydrogen sulfide, methane, and acids, are also to be expected. However, the rate of the H2 conversion by the microorganisms, how their metabolic activities impact the UGF on a short-term and long-term scale, the extent of damages microorganisms exert on the infrastructure, or potential use of microorganisms to enhance UGF are just a few questions that require urgent research to assess the role of microorganisms in this new anthropogenic use of the subsurface environment. These and many questions can be addressed in this article collection. In particular, understanding microbial community changes and activity rates will help assess operational and environmental risks, develop mitigation strategies and provide new insights on life under extreme conditions (i.e., pressure, salinity).
In this Research Topic, the editorial team particularly welcomes Original Research, Hypothesis and Theory, Method, and Review manuscripts that deal with the latest advances in microbiology in formations that are planned or currently prepared for hydrogen storage, from both fundamental and practical points of view. The ultimate objective is to promote a deeper understanding into the sustainability of UGF and generate interdisciplinary research involving microbiologists, reservoir engineers, geologists, chemists, physicists.
The topics of interest include, but are not limited to:
• Microbial diversity in different underground hydrogen storage sites or formations currently being considered for hydrogen storage
• Mechanism and impact of microbial growth under high H2 pressure
• Potential role of microorganisms in the short-term and long-term storage of hydrogen
• Potential influences of microorganisms on the hydrogen storage infrastructure systems, e.g., microbiologically influenced corrosion, biofilm growth
• Hydrogen-solid-microorganism interactions, including the influence of microbial growth on UGF geological parameters
• Mechanism and modelling of microbial impact on hydrogen storage
UGF relevant for this Research Topic include porous media, salt caverns, deep aquifers, hard rock caverns and depleted oil/gas reservoirs.
KW - Biodeterioration and biodegradation
KW - Geology
KW - Anaerobic pathways
KW - Microbial simulation,
KW - Hydrogen storage
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579042
DO - https://doi.org/10.3389/fenrg.2023.1242619
SN - 2296-598X
VL - 11
SP - 1
EP - 3
PB - Frontiers
CY - Frontiers in Energy Research
AN - OPUS4-57904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dimitrijević, Stevan P.
A1 - Dimitrijević, Silvana B.
A1 - Koerdt, Andrea
A1 - Ivanović, Aleksandra
A1 - Stefanović, Jelena
A1 - Stanković, Tanja
A1 - Gerengi, Husnu
T1 - Comparison of Corrosion Resistance of Cu and Cu72Zn28 Metals in Apricot Fermentation Liquid
N2 - The production of fruit brandies is based on distilling fermented fruit juices. Distillation equipment is usually made of copper. In traditional manufacturing, it consists of a boiler (batch) distiller, a boiler (pot), a steam pipe, and a condenser, all of which are made of pure copper. This study determined the corrosion parameters for copper (Cu) and Cu72Zn28 (in wt%) alloy in fermented apricot juice at room temperature. The fermentation process examined in this research utilized natural strains of yeast and bacteria, supplemented by active dry yeast Saccharomyces cerevisiae strains. This research used the following methods: open circuit potential (OCP), linear polarization resistance (LPR), and Tafel extrapolation to identify corrosion parameters. Cu had a 3.8-times-lower value of corrosion current density than brass, and both were within the range of 1–10 μA·cm−2, with an excellent agreement between LRP and Tafel. This study proved that Cu is an adequate material for the distillation of fruit brandies from a corrosion perspective. Despite this, there are occasional reports of corrosion damage from the field. Significant corrosion impacts can arise, as evidenced by laboratory tests discussed in this paper. In the absence of a highly corrosive environment, this study indicates that, to some extent, microbiologically influenced corrosion (MIC) can influence the degradation of the equipment material.
KW - MIC
KW - Metall
KW - Envitonment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628911
DO - https://doi.org/10.3390/ma18061253
SN - 1996-1944
VL - 18
IS - 6
SP - 1
EP - 17
PB - MDPI AG
AN - OPUS4-62891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Taghavi Kalajahi, Sara
A1 - Misra, Archismita
A1 - Koerdt, Andrea
T1 - Nanotechnology to mitigate microbiologically influenced corrosion (MIC)
N2 - Microbiologically influenced corrosion (MIC) is a crucial issue for industry and infrastructure. Biofilms are known to form on different kinds of surfaces such as metal, concrete, and medical equipment. However, in some cases the effect of microorganisms on the material can be negative for the consistency and integrity of the material. Thus, to overcome the issues raised by MIC on a system, different physical, chemical, and biological strategies have been considered; all having their own advantages, limitations, and sometimes even unwanted disadvantages. Among all the methods, biocide treatments and antifouling coatings are more common for controlling MIC, though they face some challenges. They lack specificity for MIC microorganisms, leading to cross-resistance and requiring higher concentrations. Moreover, they pose environmental risks and harm non-target organisms. Hence, the demand for eco-friendly, long-term solutions is increasing as regulations tighten. Recently, attentions have been directed to the application of nanomaterials to mitigate or control MIC due to their significant antimicrobial efficiency and their potential for lower environmental risk compared to the conventional biocides or coatings. Use of nanomaterials to inhibit MIC is very new and there is a lack of literature review on this topic. To address this issue, we present a review of the nanomaterials examined as a biocide or in a form of a coating on a surface to mitigate MIC. This review will help consolidate the existing knowledge and research on the use of nanomaterials for MIC mitigation. It will further contribute to a better understanding of the potential applications and challenges associated with using nanomaterials for MIC prevention and control.
KW - Microbiologically influenced corrosion (MIC)
KW - Biofilm
KW - Biofouling
KW - Nanobiocide
KW - Nanocoating
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599335
DO - https://doi.org/10.3389/fnano.2024.1340352
SN - 2673-3013
VL - 6
SP - 1
EP - 25
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-59933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kanzler, Daniel
A1 - Bertovic, Marija
T1 - Human-in-the-Loop: Decision Making in AI-Supported Non-Destructive Testing
N2 - The increasing integration of automation and artificial intelligence (AI) in non-destructive testing (NDT) is not only changing the inspection processes themselves, but also the way decisions are made. While technical systems can reduce error-proneness and support data processing, the ultimate responsibility remains with the human. This paper examines the role of intuition in decision-making and analyses typical errors of judgment using prospect theory and insights from cognitive psychology. It also shows how well-informed decisions can be supported in AI-supported NDT processes - through training, explainable systems, user-centred design, suitable metrics, and a targeted distribution of tasks between people and technology. Rather than replacing human intuition, AI systems should be designed to complement it. To engage effectively with such systems, inspectors require not only technical expertise, but also competencies in risk assessment, probabilistic reasoning, and critical reflection on both their own judgments and the outputs provided by AI.
T2 - DGZfP Annual Conference 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - NDT
KW - Artificial intelligence
KW - AI
KW - Decision making
KW - Human-machine interaction
KW - Human factors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645732
DO - https://doi.org/10.58286/31937
SN - 2941-4989
VL - 3
SP - 1
EP - 10
PB - NDT.net GmbH & Co. KG
AN - OPUS4-64573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matiushkina, Anna
A1 - Abram, Sarah-Luise
A1 - Tavernaro, Isabella
A1 - Richstein, R.
A1 - Reithofer, M. R.
A1 - Andresen, Elina
A1 - Michaelis, Matthias
A1 - Koch, Matthias
A1 - Resch-Genger, Ute
T1 - Quantifying Citrate Surface Ligands on Iron Oxide Nanoparticles with TGA, CHN Analysis, NMR, and RP-HPLC with UV Detection
N2 - Although citrate is frequently used as a surface ligand for nanomaterials (NMs) such as metal, metal oxide, and lanthanide-based NMs in hydrophilic environments due to its biocompatibility and simple replacement by other more strongly binding ligands in postsynthetic surface modification reactions, its quantification on NM surfaces has rarely been addressed. Here, we present a multimethod approach for citrate quantification on iron oxide nanoparticles (IONPs) broadly applied in the life and material sciences. Methods explored include thermogravimetric (TGA) and elemental (CHN) analysis, providing citrate-nonspecific information on the IONP coating, simple photometry, and citrate-selective reversed-phase high-performance liquid chromatography (RP-HPLC) with absorption (UV) detection and quantitative nuclear magnetic resonance spectroscopy (qNMR). Challenges originating from the strongly absorbing magnetic NM and paramagnetic iron species interfering with optical and NMR Methods were overcome by suitable sample preparation workflows. Our multimethod approach to citrate quantification highlights the advantages of combining specific and unspecific methods for characterizing NM Surface chemistry and method cross-validation. It also demonstrates that chemically nonselective measurements can favor an overestimation of the amount of a specific surface ligand by signal contributions from molecules remaining on the NM surface, e.g., from particle synthesis, such as initially employed ligands and/or surfactants. Our results emphasize the potential of underexplored selective RPHPLC for quantifying ligands on NMs, which does not require a multistep sample preparation workflow such as qNMR for many NMs and provides a higher sensitivity. These findings can pave the road to future applications of versatile HPLC methods in NM characterization.
KW - Advanced material
KW - Functional group
KW - Iron oxide
KW - Ligand
KW - Nano
KW - Particle
KW - Quantification
KW - Surface analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648632
DO - https://doi.org/10.1021/acs.analchem.5c03024
SN - 0003-2700
VL - 97
IS - 36
SP - 19627
EP - 19634
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-64863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Helman-Wasny, Agnieszka
ED - Martin, E.
ED - Brox, T.
ED - Lange, D.
T1 - What makes ‘Tibetan paper’ Tibetan? Understanding the materiality of Tibetan paper
N2 - Paper, as a writing support, is an integral element of the materiality of Tibetan books together with the technologies of their production. Analysis of the material features of the paper used in Tibetan written artefacts can help us to unravel their provenance, which is often unknown. First, however, we need a relatively clear understanding of the characteristic features of paper produced within particular book cultures and geographical regions at particular periods of time. This chapter offers a starting point by discussing the general characteristics of paper that originated in Tibet. Drawing on macro- and microscopic studies, it highlights the wide variety of paper types that have been used as writing supports in Tibetan written artefacts, before examining in more detail the raw materials, papermaking technologies and processes, and writing surface preparations that might justify the descriptor ‘Tibetan’ and thus grant Tibetan identity to paper.
KW - Written artefacts
KW - Paper
KW - Tibet
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649288
SN - 978-3-98887-016-2
DO - https://doi.org/10.11588/hasp.1522
SP - 113
EP - 146
PB - Heidelberg Asian Studies Publishing (HASP)
CY - Heidelberg
AN - OPUS4-64928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shenton, Martyn James
A1 - Liebner, Christian
A1 - Wanrooij, Jeroen Robert
T1 - Basic design principles of flame arrestors for decomposable gases
N2 - Flame Arrestors are safety relevant devices in chemical plants. If despite all the safety measures an explosion is initiated, they prevent damage, fatalities, and complete losses of production plants by hindering the explosion from propagating throughout the complete installation. Depending on the explosion propagation characteristics of the gas or gas mixture in question, the flame arrestors need to fulfil certain different operating requirements. In case of decomposable gases like acetylene and tetrafluoroethylene in some respect it might become necessary to violate the advice given in the standards concerning flame arrestor’s design.
KW - Decomposition
KW - Tetrafluoroethylene
KW - Flame arrestor
KW - Explosion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648995
DO - https://doi.org/10.1016/j.psep.2025.107289
SN - 0957-5820
VL - 200
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-64899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Neumann, Patrick P.
A1 - Winkler, Nicolas P.
A1 - Nerger, Tino
A1 - Lohrke, Heiko
A1 - Bartholmai, Matthias
T1 - Robotic Olfaction in Action: Field Applications and Results from Current Research
N2 - In recent decades, robotics, particularly in environmental monitoring, has made significant advances. Robots of various forms and sizes have become essential tools for data collection in environmental research. Mobile Robot Olfaction (MRO) involves mobile robots equipped with gas sensors and requires the integration of multiple disciplines, including signal processing, machine perception, autonomous navigation, and pattern recognition. Common applications of MRO include mapping gas distributions, locating and detecting gas sources, and tracking gas plumes. Aerial Robot Olfaction (ARO) is a specialized branch of MRO that adapts these concepts to aerial robots, addressing the challenges of airborne gas sensing.
This presentation highlights recent developments and results from ongoing research projects in MRO and ARO, with a focus on real-world deployment scenarios and the challenges encountered in practice.
T2 - Drohnen in der Zerstörungsfreien Prüfung
CY - Magdeburg, Germany
DA - 26.11.2025
KW - Ground and Aerial robots
KW - Gas distribution mapping
KW - Gas source localization
KW - Gas Tomography
KW - Mobile Robotic Olfaction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648928
UR - https://www.ndt.net
SP - 1
EP - 15
PB - DGZfP
AN - OPUS4-64892
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jaeger, Carsten
A1 - Lintelmann, Jutta
A1 - Franke, Raimo
A1 - Artati, Anna
A1 - Cecil, Alexander
A1 - Broda, Frank
A1 - Klawonn, Frank
A1 - Erban, Alexander
A1 - Kopka, Joachim
A1 - Fuchs, Beate
A1 - Sommer, Ulf
A1 - Neumann-Schaal, Meina
A1 - O'Connor, Gavin
T1 - Analytical practices, use and needs of standard and reference materials in the German-speaking metabolomics community: results of an online survey
N2 - Introduction
Since the early 2000s, metabolomics has grown rapidly, becoming integral to fields like life sciences, health, and environmental research. This expansion has led to the formation of national and international societies, such as Germany’s DGMet, to tackle emerging challenges. One of DGMet’s goals is to improve measurement quality by assessing community needs for harmonization and standardization. A recent survey within the German-speaking community aimed to identify current practices and gaps in the use of chemical standards and reference materials, to guide future standardization efforts and collaborative initiatives.
Methods
An online survey was conducted between June 2023 and April 2024. The survey consisted of 38 key questions and was open to research institutions from Germany, Austria, and Switzerland.
Results
The survey was accessed by 68 laboratories, with 23 institutes providing complete or partial responses (34% response rate), which is comparable to rates reported in similar surveys within the metabolomics and lipidomics communities. Respondents were mainly experienced researchers from Germany, focusing mainly on health-related (“red”) metabolomics, as indicated by 78% of the respondents, followed by microbial (“grey”, 48%) and plant (“green”, 39%) metabolomics (multiple answers possible). The use of targeted methods was reported more frequently (91%) than that of non-targeted methods (78%), whereas metabolite fractions studied were equally split between polar, midpolar and lipid fractions (83% each). Human (74%), mouse (61%) and Arabidopsis (30%) were the most frequently studied organisms. Most participants used synthetic chemical standards for instrument qualification (83%), calibration (78%), and metabolite identification (74%), while matrix reference materials were mainly applied for quality control (52%) and method validation (44%). There was a strong demand for more standards, especially for metabolite identification and quantification, with cost being a major barrier, particularly for isotopically labelled standards and certified reference materials.
Conclusions
Valuable insights into the use of standards and reference materials within the German-speaking metabolomics community were obtained. Moving forward, the community should address critical gaps in metabolomics standardization. To achieve this, it must share its knowledge, articulate its needs clearly, and actively engage in joint efforts with national metrology institutes and international standardization initiatives.
KW - Reference material
KW - Chemical standard
KW - Metabolomics
KW - Mass spectrometry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647303
DO - https://doi.org/10.1007/s11306-025-02360-x
VL - 21
IS - 6
SP - 1
EP - 11
PB - Springer-Nature
CY - Heidelberg
AN - OPUS4-64730
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pelkner, Matthias
A1 - Neubauer, Andreas
A1 - Reimund, Verena
A1 - Erthner, Thomas
A1 - Panke, Nicolai
A1 - Kreutzbruck, Marc
T1 - Automatisierte Streuflussprüfung und Bewertung von Zylilnderlagerringen unter Anwendung von GMR-Sensorarrays
N2 - Dieser Beitrag behandelt die automatisierte Streuflussprüfung an
Zylinderlagerschalen. Die Anforderung an das im Verbundprojekt mit
Industriepartnern aufgebaute System waren neben einer schnellen Detektion von
Mikrorissen die Bewertung und grafische Darstellung der ermittelten Risssignale.
Mithilfe neu angepasster GMR-Sensorarrays war es möglich, die Prüfung der
Außen-, Innen- und Stirnflächen in kürzester Zeit (< 2 min) durchzuführen und
Risse mit einer Tiefe unterhalb der geforderten 50 µm zu detektieren (Risse mit
Tiefen von 30 µm konnten noch mit einem guten Signal-Rausch-Abstand besser 6
dB detektiert werden). Eine selbst entwickelte Messsoftware bereitet die Daten auf
und stellt sie grafisch dar. Zusätzlich werden die Mikrorisse bewertet.
T2 - DACH-Jahrestagung 2012
CY - Graz, Austria
DA - 17.09.2012
KW - Streufluss
KW - GMR
KW - Sensorarrays
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-279490
SN - 978-3-940283-44-3
IS - DGZfP-BB 136
SP - Mo.2.A.2, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-27949
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalmbach, J.
A1 - Wang, Cui
A1 - You, Yi
A1 - Förster, C.
A1 - Schubert, H.
A1 - Heinze, K.
A1 - Resch-Genger, Ute
A1 - Seitz, M.
T1 - Near-IR to near-IR upconversion luminescence in molecular chromium ytterbium salts
N2 - Upconversion photoluminescence in hetero-oligonuclear metal complex architectures featuring organic ligands is an interesting but still rarely observed phenomenon, despite its great potential from a basic research and application perspective. In this context, a new photonic material consisting of molecular chromium(III) and ytterbium(III) complex Ions was developed that exhibits excitation-power density-dependent cooperative sensitization of the chromium-centered 2E/2T1 phosphorescence at approximately 775 nm after excitation of the ytterbium band 2F7/2!2F5/2 at approximately 980 nm in the solid state at ambient temperature. The upconversion process is insensitive to atmospheric oxygen and can be observed in the presence of water molecules in the crystal lattice.
KW - Upconversion
KW - Lanthanide
KW - Photoluminescence
KW - Quantum yield
KW - Photophysics
KW - Lifetime
KW - Sensor
KW - NIR
KW - Cr(III)
KW - Yb(III) complex
KW - Crystal
KW - Triplet-triplet annihilation
KW - Sensitization
KW - Light harvesting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512619
DO - https://doi.org/10.1002/anie.202007200
SN - 1433-7851
SN - 1521-3773
VL - 59
IS - 42
SP - 18804
EP - 18808
PB - Wiley
CY - Weinheim
AN - OPUS4-51261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stargardt, Patrick
A1 - Bresch, Sophie
A1 - Falkenberg, Rainer
A1 - Mieller, Björn
T1 - Effect of Reaction Layers on Internal Stresses in Co‐Fired Multilayers of Calcium Manganate and Calcium Cobaltite
N2 - A widespread recovery of waste heat requires a cost‐effective production of thermoelectric generators. Thermoelectric oxides are predestined for use at high temperatures. For manufacturing reasons, a multilayer generator design will be easily scalable and cost‐effective. To evaluate the potential of ceramic multilayer technology for that purpose, a multilayer of the promising thermoelectric oxides calcium cobaltite (Ca3Co4O9), calcium manganate (CMO, CaMnO3), and glass–ceramic insulation layers is fabricated. Cracks and reaction layers at the interfaces are observed in the microstructure. The compositions of these reaction layers are identified by energy‐dispersive X‐ray spectroscopy and X‐ray diffraction. Mechanical and thermal properties of all layers are compiled from literature or determined by purposeful sample preparation and testing. Based on this data set, the internal stresses in the multilayer after co‐firing are calculated numerically. It is shown that tensile stresses in the range of 50 MPa occur in the CMO layers. The reaction layers have only a minor influence on the level of these residual stresses. Herein, it is proven that the material system is basically suitable for multilayer generator production, but that the co‐firing process and the layer structure must be adapted to improve densification and reduce the tensile stresses in the CMO.
KW - Ceramic multilayers
KW - Co-firings
KW - Internal stresses
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601626
DO - https://doi.org/10.1002/pssa.202300956
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-60162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eddah, Mustapha
A1 - Markötter, Henning
A1 - Mieller, Björn
A1 - Widjaja, Martinus Putra
A1 - Beckmann, Jörg
A1 - Bruno, Giovanni
T1 - Multi-energy high dynamic range synchrotron X-ray computed tomography
N2 - Synchrotron X-ray computed tomography (SXCT) is regularly used in materials science to correlate structural properties with macroscopic properties and to optimize manufacturing processes. The X-ray beam energy must be adapted to the sample properties, such as size and density. If both strongly and weakly absorbing materials are present, the contrast to the weakly absorbing materials is lost, resulting in image artifacts and a poor signal-tonoise ratio (SNR). One particular example is a low-temperature co-fired ceramics (LTCC), in which metal connections are embedded in a ceramic matrix and form 3-dimensional conducting structures. This article describes a method of combining SXCT scans acquired at different beam energies, significantly reducing metal artifacts, and improving image quality. We show how to solve the difficult task of merging the scans at low and high beam energy. Our proposed merging approach achieves up to 35 % improvement in SNR within ceramic regions adjacent to metallic conductors. In this way, previously inaccessible regions within the ceramic structure close to the metallic conductors are made accessible. The paper further discusses methodological requirements, limitations, and potential extensions of the presented multi-energy SXCT merging technique.
KW - Synchrotron computed tomography
KW - Reconstruction algorithm
KW - High dynamic range
KW - Data merging
KW - Low-temperature cofired ceramics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652339
DO - https://doi.org/10.1016/j.tmater.2025.100079
SN - 2949-673X
VL - 9
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michna, A.
A1 - Pomorksa, A.
A1 - Özcan Sandikcioglu, Özlem
T1 - Biocompatible Macroion/Growth Factor Assemblies for Medical Applications
N2 - Growth factors are a class of proteins that play a role in the proliferation (the increase in the number of cells resulting from cell division) and differentiation (when a cell undergoes changes in gene expression becoming a more specific type of cell) of cells. They can have both positive (accelerating the normal healing process) and negative effects (causing cancer) on disease progression and have potential applications in gene therapy and wound healing. However, their short half-life, low stability, and susceptibility to degradation by enzymes at body temperature make them easily degradable in vivo. To improve their effectiveness and stability, growth factors require carriers for delivery that protect them from heat, pH changes, and proteolysis. These carriers should also be able to deliver the growth factors to their intended destination. This review focuses on the current scientific literature concerning the physicochemical properties (such as biocompatibility, high affinity for binding growth factors, improved bioactivity and stability of the growth factors, protection from heat, pH changes or appropriate electric charge for growth factor attachment via electrostatic interactions) of macroions, growth factors, and macroion-growth factor assemblies, as well as their potential uses in medicine (e.g., diabetic wound healing, tissue regeneration, and cancer therapy).
Specific attention is given to three types of growth factors: vascular endothelial growth factors, human fibroblast growth factors, and neurotrophins, as well as selected biocompatible synthetic macroions (obtained through standard polymerization techniques) and polysaccharides (natural macroions composed of repeating monomeric units of monosaccharides). Understanding the mechanisms by which growth factors bind to potential carriers could lead to more effective delivery methods for these proteins, which are of significant interest in the diagnosis and treatment of neurodegenerative and civilization diseases, as well as in the healing of chronic wounds.
KW - Polyelectrolytes
KW - Polysaccharides
KW - Vascular endothelial growth factor
KW - Human fibroblast growth factors
KW - Neurotrophins
KW - Macroion/growth factor assemblies
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579820
DO - https://doi.org/10.3390/biom13040609
VL - 13
IS - 4
SP - 1
EP - 48
PB - MDPI
AN - OPUS4-57982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Günster, Jens
T1 - Towards a debinding-free additive manufacturing of ceramics: A development perspective of water-based LSD and LIS technologies
N2 - Ceramic additive manufacturing (AM) requires a complex process chain with various post-processing steps that require expensive machines and special expertise. The key to further market penetration is AM that makes it possible to integrate into an already established ceramic process chain. Most successful AM technologies for ceramics are, however, based on processes that initially have been developed for polymeric materials. For ceramics AM, polymers or precursors are loaded with ceramic particles. This strategy facilitates the entry into AM, however the introduction of organic additives into the ceramic process chain represents a considerable technological challenge to ultimately obtain a ceramic component after additive shaping. In the present communication, two technologies based on ceramic suspensions will be introduced, the “layerwise slurry deposition” (LSD) and “laser induced slip casting” (LIS) technology. Both technologies take advantage of the high packing densities reached by conventional slip casting and moreover enable the processing of fines, even nanoparticles.
KW - Additive Manufacturing
KW - Ceramic
KW - Water-based
KW - Debinding
KW - Slurry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605531
DO - https://doi.org/10.1016/j.oceram.2024.100632
SN - 2666-5395
VL - 19
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-60553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromer, Charlotte
A1 - Katz, Aaron
A1 - Feldmann, Ines
A1 - Laux, Peter
A1 - Luch, Andreas
A1 - Tschiche, Harald R.
T1 - A targeted fluorescent nanosensor for ratiometric pH sensing at the cell surface
N2 - AbstractThe correlation between altered extracellular pH and various pathological conditions, including cancer, inflammation and metabolic disorders, is well known. Bulk pH measurements cannot report the extracellular pH value at the cell surface. However, there is a limited number of suitable tools for measuring the extracellular pH of cells with high spatial resolution, and none of them are commonly used in laboratories around the world. In this study, a versatile ratiometric nanosensor for the measurement of extracellular pH was developed. The nanosensor consists of biocompatible polystyrene nanoparticles loaded with the pH-inert reference dye Nile red and is surface functionalized with a pH-responsive fluorescein dye. Equipped with a targeting moiety, the nanosensor can adhere to cell membranes, allowing direct measurement of extracellular pH at the cell surface. The nanosensor exhibits a sensitive ratiometric pH response within the range of 5.5–9.0, with a calculated pKa of 7.47. This range optimally covers the extracellular pH (pHe) of most healthy cells and cells in which the pHe is abnormal, such as cancer cells. In combination with the nanosensors ability to target cell membranes, its high robustness, reversibility and its biocompatibility, the pHe nanosensor proves to be well suited for in-situ measurement of extracellular pH, even over extended time periods. This pH nanosensor has the potential to advance biomedical research by improving our understanding of cellular microenvironments, where extracellular pH plays an important role.
KW - pH sensor
KW - pH
KW - Targeting, Nanoparticles
KW - pHe
KW - Nanosensor
KW - Extracellular pH
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604339
DO - https://doi.org/10.1038/s41598-024-62976-2
VL - 14
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-60433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Moritz
A1 - Stawarczyk, Bogna
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Influence of additives and binder on the physical properties of dental silicate glass-ceramic feedstock for additive manufacturing
N2 - Objectives
The aim of the study was to investigate the impact of organic additives (binder, plasticizer, and the cross-linking ink) in the formulation of water-based feedstocks on the properties of a dental feldspathic glass-ceramic material developed for the slurry-based additive manufacturing technology “LSD-print.”
Material and methods
Three water-based feldspathic feedstocks were produced to study the effects of polyvinyl alcohol (AC1) and poly (sodium 4-styrenesulfonate) (AC2) as binder systems. A feedstock without organic additives was tested as the control group (CG). Disc-shaped (n = 15) and bar (n = 7) specimens were slip-cast and characterized in the green and fired states. In the green state, density and flexural strength were measured. In the fired state, density, shrinkage, flexural strength (FS), Weibull modulus, fracture toughness (KIC), Martens parameters, and microstructure were analyzed. Disc-shaped and bar specimens were also cut from commercially available CAD/CAM blocks and used as a target reference (TR) for the fired state.
Results
In the green state, CG showed the highest bulk density but the lowest FS, while the highest FS in the green state was achieved with the addition of a cross-linking ink. After firing, no significant differences in density and a similar microstructure were observed for all slip-cast groups, indicating that almost complete densification could be achieved. The CAD/CAM specimens showed the highest mean FS, Weibull modulus, and KIC, with significant differences between some of the slip-cast groups.
Significance
These results suggest that the investigated feedstocks are promising candidates for the slurry-based additive manufacturing of restorations meeting the class 1a requirements according to DIN EN ISO 6871:2019–01.
KW - Firing
KW - 3D-printing
KW - Silicate glass-ceramics
KW - Debinding
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600516
DO - https://doi.org/10.1016/j.jmbbm.2024.106563
SN - 1751-6161
VL - 155
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-60051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knabe, C.
A1 - Stiller, M.
A1 - Kampschulte, M.
A1 - Wilbig, Janka
A1 - Peleska, B.
A1 - Günster, Jens
A1 - Gildenhaar, R.
A1 - Berger, G.
A1 - Rack, A.
A1 - Linow, U.
A1 - Heiland, M.
A1 - Rendenbach, C.
A1 - Koerdt, S.
A1 - Steffen, C.
A1 - Houshmand, A.
A1 - Xiang-Tischhauser, L.
A1 - Adel-Khattab, D.
T1 - A tissue engineered 3D printed calcium alkali phosphate bioceramic bone graft enables vascularization and regeneration of critical-size discontinuity bony defects in vivo
N2 - Recently, efforts towards the development of patient-specific 3D printed scaffolds for bone tissue engineering from bioactive ceramics have continuously intensified. For reconstruction of segmental defects after subtotal mandibulectomy a suitable tissue engineered bioceramic bone graft needs to be endowed with homogenously distributed osteoblasts in order to mimic the advantageous features of vascularized autologous fibula grafts, which represent the standard of care, contain osteogenic cells and are transplanted with the respective blood vessel. Consequently, inducing vascularization early on is pivotal for bone tissue engineering. The current study explored an advanced bone tissue engineering approach combining an advanced 3D printing technique for bioactive resorbable ceramic scaffolds with a perfusion cell culture technique for pre-colonization with mesenchymal stem cells, and with an intrinsic angiogenesis technique for regenerating critical size, segmental discontinuity defects in vivo applying a rat model. To this end, the effect of differing Si-CAOP (silica containing calcium alkali orthophosphate) scaffold microarchitecture arising from 3D powder bed printing (RP) or the Schwarzwalder Somers (SSM) replica fabrication technique on vascularization and bone regeneration was analyzed in vivo. In 80 rats 6-mm segmental discontinuity defects were created in the left femur.
KW - Additive Manufacturing
KW - Bio active ceramic
KW - In-vivo
KW - Alcium alkali phosphate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584555
DO - https://doi.org/10.3389/fbioe.2023.1221314
SN - 2296-4185
VL - 11
SP - 1
EP - 20
PB - Frontiers SA
CY - Lausanne
AN - OPUS4-58455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knabe, Christine
A1 - Adel-Khattab, Doaa
A1 - Rezk, Mohamed
A1 - Cheng, Jia
A1 - Berger, Georg
A1 - Gildenhaar, Renate
A1 - Wilbig, Janka
A1 - Günster, Jens
A1 - Rack, Alexander
A1 - Heiland, Max
A1 - Knauf, Tom
A1 - Stiller, Michael
T1 - Osteogenic Effect of a Bioactive Calcium Alkali Phosphate Bone Substitute in Humans
N2 - (1) Background: The desire to avoid autograft harvesting in implant dentistry has prompted an ever-increasing quest for bioceramic bone substitutes, which stimulate osteogenesis while resorbing in a timely fashion. Consequently, a highly bioactive silicon containing calcium alkali orthophosphate (Si-CAP) material was created, which previously was shown to induce greater bone cell maturation and bone neo-formation than β-tricalcium phosphate (β-TCP) in vivo as well as in vitro. Our study tested the hypothesis that the enhanced effect on bone cell function in vitro and in sheep in vivo would lead to more copious bone neoformation in patients following sinus floor augmentation (SFA) employing Si-CAP when compared to β-TCP. (2) Methods: The effects of Si-CAP on osteogenesis and Si-CAP resorbability were evaluated in biopsies harvested from 38 patients six months after SFA in comparison to β-TCP employing undecalcified histology, histomorphometry, and immunohistochemical analysis of osteogenic marker expression. (3) Results: Si-CAP as well as β-TCP supported matrix mineralization and bone formation. Apically furthest away from the original bone tissue, Si-CAP induced significantly higher bone formation, bone-bonding (bone-bioceramic contact), and granule resorption than β-TCP. This was in conjunction with a higher expression of osteogenic markers. (4) Conclusions: Si-CAP induced higher and more advanced bone formation and resorbability than β-TCP, while β-TCP’s remarkable osteoconductivity has been widely demonstrated. Hence, Si-CAP constitutes a well-suited bioactive graft choice for SFA in the clinical arena.
KW - Silicon release
KW - Bioceramics
KW - Calcium alkali orthophosphate materials
KW - Bioactive bone grafting material
KW - Bioactivity
KW - Osteogenesis
KW - Bone regeneration
KW - Sinus floor augmentation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591015
DO - https://doi.org/10.3390/bioengineering10121408
VL - 10
IS - 12
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-59101
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, Juan Carlos
A1 - Fateri, Miranda
A1 - Kalhöfer, Eckhard
A1 - Schubert, Tim
A1 - Meyer, Lena
A1 - Kolsch, Nico
A1 - Brandic Lipinska, Monica
A1 - Davenport, Robert
A1 - Imhof, Barbara
A1 - Waclavicek, René
A1 - Sperl, Matthias
A1 - Makaya, Advenit
A1 - Günster, Jens
T1 - Laser melting manufacturing of large elements of lunar regolith simulant for paving on the Moon
N2 - The next steps for the expansion of the human presence in the solar system will be taken on the Moon. However, due to the low lunar gravity, the suspended dust generated when lunar rovers move across the lunar soil is a significant risk for lunar missions as it can affect the systems of the exploration vehicles. One solution to mitigate this problem is the construction of roads and landing pads on the Moon. In addition, to increase the sustainability of future lunar missions, in-situ resource utilization (ISRU) techniques must be developed. In this paper, the use of concentrated light for paving on the Moon by melting the lunar regolith is investigated. As a substitute of the concentrated sunlight, a high-power CO2 laser is used in the experiments. With this set-up, a maximum laser spot diameter of 100 mm can be achieved, which translates in high thicknesses of the consolidated layers. Furthermore, the lunar regolith simulant EAC-1A is used as a substitute of the actual lunar soil. At the end of the study, large samples (approximately 250 × 250 mm) with interlocking capabilities were fabricated by melting the lunar simulant with the laser directly on the powder bed. Large areas of lunar soil can be covered with these samples and serve as roads and landing pads, decreasing the propagation of lunar dust. These manufactured samples were analysed regarding their ineralogical composition, internal structure and mechanical properties.
KW - Regolith
KW - ISRU
KW - Moon
KW - Laser
KW - Additive manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585985
DO - https://doi.org/10.1038/s41598-023-42008-1
SN - 2045-2322
VL - 13
SP - 1
EP - 10
PB - Springer
AN - OPUS4-58598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Catanzaro, Ilaria
A1 - Gerrits, Ruben
A1 - Feldmann, Ines
A1 - Gorbushina, Anna
A1 - Onofri, Silvano
A1 - Schumacher, Julia
T1 - Deletion of the polyketide synthase‐encoding gene pks1 prevents melanization in the extremophilic fungus Cryomyces antarcticus
N2 - Cryomyces antarcticus, a melanized cryptoendolithic fungus endemic to Antarctica, can tolerate environmental conditions as severe as those in space. Particularly, its ability to withstand ionizing radiation has been attributed to the presence of thick and highly melanized cell walls, which—according to a previous investigation—may contain both 1,8‐dihydroxynaphthalene (DHN) and L‐3,4 dihydroxyphenylalanine (L‐DOPA) melanin. The genes putatively involved in the synthesis of DHN melanin were identified in the genome of C. antarcticus. Most important is capks1 encoding a non‐reducing polyketide synthase (PKS) and being the ortholog of the functionally characterized kppks1 from the rock‐inhabiting fungus Knufia petricola. The co‐expression of CaPKS1 or KpPKS1 with a 4′‐phosphopantetheinyl transferase in Saccharomyces cerevisiae resulted in the formation of a yellowish pigment, suggesting that CaPKS1 is the enzyme providing the precursor for DHN melanin. To dissect the composition and function of the melanin layer in the outer cell wall of C. antarcticus, non‐melanized mutants were generated by CRISPR/Cas9‐mediated genome editing. Notwithstanding its slow growth (up to months), three independent non‐melanized Δcapks1 mutants were obtained. The mutants exhibited growth similar to the wild type and a light pinkish pigmentation, which is presumably due to carotenoids. Interestingly, visible light had an adverse effect on growth of both melanized wild‐type and non‐melanized Δcapks1 strains. Further evidence that light can pass the melanized cell walls derives from a mutant expressing a H2B‐GFP fusion protein, which can be detected by fluorescence microscopy. In conclusion, the study reports on the first genetic manipulation of C. antarcticus, resulting in non‐melanized mutants and demonstrating that the melanin is rather of the DHN type. These mutants will allow to elucidate the relevance of melanization for surviving extreme conditions found in the natural habitat as well as in space.
KW - Astrobiology
KW - Black fungi
KW - CRISPR/Cas9
KW - DHN melanin
KW - Cryptoendolithism
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606599
DO - https://doi.org/10.1002/iub.2895
SN - 1521-6551
VL - 76
IS - 12
SP - 1072
EP - 1090
PB - Wiley
AN - OPUS4-60659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sobetkii, Arcadii
A1 - Mosinoiu, Laurentiu-Florin
A1 - Caramarin, Stefania
A1 - Mitrica, Dumitru
A1 - Cursaru, Laura-Madalina
A1 - Matei, Alexandru-Cristian
A1 - Tudor, Ioan-Albert
A1 - Serban, Beatrice-Adriana
A1 - Ghita, Mihai
A1 - Vitan, Nicoleta
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
A1 - Postolnyi, Bogdan
A1 - Pogrebnjak, Alexander
T1 - Deposition and Characterization of Cu-Enhanced High-Entropy Alloy Coatings via DC Magnetron Sputtering
N2 - Protection against microbiologically influenced corrosion (MIC) is critical for materials used in aquatic environments, as MIC accelerates material degradation and leads to faster structural failure. Copper (Cu) has the potential to substantially improve the MIC resistance in alloys. In this study, high-entropy alloy (HEA) coatings containing Cu were deposited using DC (Direct Current) magnetron sputtering to enhance the corrosion resistance and mechanical properties of various substrates. Two CuCrFeMnNi HEA compositions in the form of bulk alloys and PVD (Physical Vapor Deposition) coatings, with 5% and 10% Cu, were analyzed for their microstructural, mechanical, and anticorrosive characteristics. Deposition parameters were varied to select the optimal values. Microstructural evaluations using SEM-EDS (scanning electron microscopy and energy dispersive X-ray spectroscopy), XRD (X-ray diffraction), and AFM (atomic force microscopy) revealed uniform, dense coatings with good adhesion composed of dendritic and interdendritic BCC (body-centered cubic) and FCC (face centered cubic) structures, respectively. Microhardness tests indicated improved mechanical properties for the samples coated with developed HEAs. The coatings exhibited improved corrosion resistance in NaCl solution, the 10% Cu composition displaying the highest polarization resistance and lowest corrosion rate. These findings suggest that Cu-containing HEA coatings are promising candidates for applications requiring enhanced corrosion protection.
KW - High-entropy alloys (HEAs)
KW - DC magnetron sputtering
KW - Cu-enhanced coatings
KW - Corrosion resistance
KW - Microstructural characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625561
DO - https://doi.org/10.3390/app15041917
SN - 2076-3417
VL - 15
IS - 4
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-62556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mallikarjun, Jhenkhar
A1 - Gorbushina, Anna
A1 - Kuzyakov, Yakov
A1 - Koester, Moritz
A1 - Castro, Rodrigo
A1 - Yudina, Anna
A1 - Abdallah, Khaled
A1 - Matus, Francisco J.
A1 - Dippold, Michaela A.
T1 - Post-fire recovery of temperate and mediterranean ecosystems: An interplay between fire severity, soil nutrients, and vegetation from early-stage to decadal-scale dynamics
N2 - Wildfires strongly alter soil properties, which in turn affect ecosystem recovery over extended periods, though long-term impacts are less certain. This study investigated a 14-year post-fire chronosequence in Chile’s mediterranean and temperate humid forests, revealing ecosystem-specific soil properties and nutrient recovery mechanisms. By analysing sites at successional stages, the chronosequence approach assessed temporal changes and ecosystem recovery, revealing long-term wildfire effects on soil dynamics and nutrients recovery.
Wildfires raised soil bulk density to 0.9 g cm−3 in humid temperate and 1.2 g cm−3 in mediterranean ecosystems. Mediterranean soils experienced greater compaction from organic matter loss, soil aggregate destruction, ash-clogged pores, and topsoil erosion. Soil texture shifts were ecosystem-dependent: mediterranean soils increased 10–12 % in clay and silt through ash redistribution and aggregation, while temperate soils saw sand content rise by 0.74 % and 0.32 % yearly at 0–5 and 5–10 cm depths from thermal disaggregation and erosion. Ground vegetation recovers quickly, but physical soil properties like bulk density require over 14 years to return to pre-fire conditions.
In humid temperate forests, ash input initially increased soil pH (4.8 to 5.8), reducing acidity, mitigating aluminium toxicity, while increasing nutrient availability. Base cation stocks increased in mediterranean woodlands (e.g., Ca: up to 0.41 Mg ha−1 y−1) due to ash retention, lower leaching, and ash infiltration into subsoil. Nutrient stocks in humid forests recovered slowly (Ca: 0.087–0.13 Mg ha−1 y−1) due to rainfall-driven leaching and low subsoil reserves. Carbon and N losses were restricted to the litter horizon in temperate forests, recovering via fire-resistant tree inputs, whereas mediterranean soils suffered severe C and N depletion from vegetation loss, erosion, and low N fixation.
Fire effects and recovery are ecosystem-specific, shaped by landscape, geology, hydrology, and vegetation resilience. Understanding how fire regimes affect soil and nutrient recovery is vital for improving projections in fire-prone regions.
KW - Historical fire & Wildfire
KW - Nutrients Ecosystem recovery & Vegetation succession
KW - Chronosequence approach
KW - Losses of nutrients & Nutrients stocks
KW - Wildfire
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642918
DO - https://doi.org/10.1016/j.catena.2025.109431
SN - 0341-8162
VL - 260
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-64291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna
A1 - König, N.F.
A1 - De Marzi, A.
A1 - Zocca, Andrea
A1 - Franchin, G.
A1 - Bermejo, R.
A1 - Colombo, P.
A1 - Günster, Jens
T1 - Linear volumetric additive manufacturing of zirconia from a transparent photopolymerizable ceramic slurry via Xolography
N2 - Advanced ceramics printed with photon-based additive manufacturing deals with anisotropic mechanical properties from the layer-by-layer manufacturing. Motivated by the success in using highly filled transparent slurries containing nanoparticles for powder-based two-photon-polymerization (2PP) for advanced ceramic printing, this works approach is the transfer to Xolography, a volumetric additive manufacturing technology based on linear two-photon excitation and without recoating steps. This paper reports the results of a preliminary investigation optimizing the photocurable slurry to the requirements of Xolography in terms of transparency, over a significantly larger mean free path, compared to 2PP. A feedstock filled with 70 % weight fraction of ceramic particles (∼30 vol%) exhibiting an exceptionally high degree of transparency in the relevant wavelength range of 400–800 nm was prepared from 5 nm zirconia nanoparticles. The high transparency of the photocurable slurry is attributed to the near-monomodal particle size distribution of the zirconia nanoparticles used.
KW - Additive manufacturing
KW - Xolography
KW - Ceramic
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608908
DO - https://doi.org/10.1016/j.oceram.2024.100655
SN - 2666-5395
VL - 19
SP - 1
EP - 9
PB - Elsevier BV
AN - OPUS4-60890
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schumacher, Julia
T1 - CRISPR-Cas9 in der Materialforschung - Den gesteinsbesiedelnden Pilzen auf der Spur
T1 - CRISPR-Cas9 in materials research - On the trail of rock-inhabiting fungi
N2 - Das mikroskopische Leben auf exponierten Oberflächen ist genügsam und kooperativ. Gesteinsbesiedelnde schwarze Pilze, Grünalgen und Cyanobakterien unterstützen einander in der Eroberung von Felsen, Mauern, Denkmälern, Dächern, Fassaden und Sonnenkollektoren. Bedeutend sind die schwarzen Pilze als Gesteinszerstörer und Biofilmbildner. Ihre massiven Zellwände und ihr langsames Wachstum machen sie stresstolerant und fordern zugleich die experimentelle Forschung heraus. In der Materialforschung können Biofilme erwünscht oder unerwünscht sein. Biofilme auf Fassaden können das Innenstadtklima positiv beeinflussen, während sie auf einem Marmordenkmal unwillkommen sind. Ohne tieferes Verständnis der angepassten Mikroben ist weder ihre Bekämpfung noch ihre gezielte Förderung auf Materialien möglich. Hier treffen sich Genetik und Materialforschung: Die CRISPR-Cas9-Technologie ermöglicht es, die Genome der Pilze für funktionale Analysen zu editieren, um die Mechanismen der Materialbesiedlung und Materialschädigung zu entschlüsseln.
N2 - Rock-inhabiting black fungi are adapted to the harsh life on rocks in deserts and release minerals from the rocks. The same adaptations enable these fungi to colonize man-made surfaces such as monuments, building facades and solar systems. Black fungi are often associated with phototrophic microorganisms. The slow growth and the melanized cell walls, which protect the fungi from extreme environmental infuences, render molecular biological and genetic engineering methods diffcult, which is why little is known about the biology of these fungi. Knufa petricola was selected to understand the processes of material colonization and damage with the help of adapted methods such as CRISPR-Cas9-mediated genome editing.
KW - Knufia petricola
KW - Schwarze Pilze
KW - Bioflme
KW - Genomeditierung
KW - Pigmente
KW - Multiplexing
KW - Resistenzkassette
KW - Transformanten
KW - Knufia petricola
KW - Black fungi
KW - Biofilms
KW - Pigments
KW - Genome editing
KW - Multiplexing
KW - Resistance cassette
KW - Transformants
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620500
DO - https://doi.org/10.11576/biuz-7595
SN - 0045-205X
SN - 1521-415X
N1 - Volltext (PDF) in deutsch und englisch - Full text (PDF) in German and English
VL - 54
SP - 41
EP - 50
PB - Verband Biologie, Biowissenschaften und Biomedizin in Deutschland (VBiO)
CY - München
AN - OPUS4-62050
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wittwer, Philipp
A1 - Roesch, Philipp
A1 - Vogel, Christian
A1 - Simon, Fabian
A1 - Gehrenkemper, Lennart
A1 - Feldmann, Ines
A1 - Simon, Franz-Georg
T1 - Less Is More: Influence of Cross-Linking Agent Concentration on PFOS Adsorption in Chitosan
N2 - As a result of the continuous use of persistent per- and polyfluoroalkyl substances (PFAS), e.g., in aviation firefighting foams, contamination with PFAS has been found in soil, groundwater, and surface water around thousands of industrial and military installations. Due to their harmful (environmental) potential, further dispersion in the environment needs to be stopped, which can be achieved by appropriate absorption materials. In this work, the influence of the cross-linking agent epichlorohydrin (ECH) concentration on the perfluorooctanesulfonic acid (PFOS) adsorption capacity of chitosan gel was investigated. It was found that higher ECH concentration during the cross-linking step decreases the PFOS adsorption capacity of the cross-linked chitosan gel from 0% to 4% ECH solution by about 15%. Using a concentration of 1%, ECH resulted still in an acid-stable material, and a maximum PFOS loading capacity of 4.04 mmol/g was obtained, one of the highest described in the literature. Furthermore, we used a rapid small-scale column test to compare the PFOS adsorption capacity of chitosan and activated carbon, each in both milled and unmilled form. Unmilled chitosan showed the highest PFOS adsorption capacity considering adsorption material dry masses (>0.9 and <0.4 mmol/g for both types of chitosan and activated carbon, respectively). Milled activated carbon proved to be the better adsorption material, considering the fixed volume of the adsorber (>99.9% PFOS adsorbed). Overall, the cross-linking agent concentration in chitosan is a crucial factor influencing its PFOS absorption potential. Our results feature cross-linked chitosan as an effective economic and ecologic alternative for PFOS adsorption in aqueous solutions.
KW - Combustion Ion Chromatography
KW - Per- and Polyfluoroalkyl substances (PFAS)
KW - Remediation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618406
DO - https://doi.org/10.3390/app142311145
VL - 14
IS - 23
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-61840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schumacher, Julia
T1 - Schwarze Pilze: Robuste Multitalente für die Biotechnologie
T1 - Black fungi: Robust all-rounders for biotechnology
N2 - Knufia petricola ist ein gesteinsbesiedelnder Pilz aus der polyphyletischen Gruppe der schwarzen Pilze. Diese Pilze entwickelten außergewöhnliche – und bisher kaum erforschte – Fähigkeiten, in verschiedenen extremen Umgebungen zu gedeihen. Die Nutzung der genetischen Vielfalt des Genoms von schwarzen Pilzen und die Nutzung von K. petricola als alternativer Wirt für die Produktion von Enzymen und Sekundärmetaboliten eröffnen Perspektiven für die Nutzung dieser bislang wenig bekannten Pilze für biotechnologische Anwendungen.
N2 - Knufia petricola is a rock-inhabiting fungus belonging to the polyphyletic group of black fungi. These fungi developed extraordinary – and so far hardly studied – capabilities to thrive in different extreme environments. Accessing the genetic diversity of black fungal genomes and using K. petricola as an alternative host for producing enzymes and secondary metabolites opens perspectives for utilizing these so far little recognized fungi for biotechnological applications.
KW - Knufia petricola
KW - Fungal pigments
KW - Genetic engineering
KW - Knufia petricola
KW - Pilzpigmente
KW - Gentechnik
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628150
DO - https://doi.org/10.1007/s12268-025-2442-8
SN - 0947-0867
SN - 1868-6249
VL - 31
IS - 2
SP - 159
EP - 162
PB - Springer
CY - Heidelberg
AN - OPUS4-62815
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erdmann, Eileen
A1 - Nitsche, Sarah
A1 - Gorbushina, Anna
A1 - Schumacher, Julia
T1 - Genetic Engineering of the Rock Inhabitant Knufia petricola Provides Insight Into the Biology of Extremotolerant Black Fungi
N2 - Black microcolonial fungi (Ascomycetes from Arthonio-, Dothideo-, and Eurotiomycetes) are stress-tolerant and persistent dwellers of natural and anthropogenic extreme habitats. They exhibit slow yeast-like or meristematic growth, do not form specialized reproduction structures and accumulate the black pigment 1,8-dihydroxynaphthalene (DHN) melanin in the multilayered cell walls. To understand how black fungi live, survive, colonize mineral substrates, and interact with phototrophs genetic methods are needed to test these functions and interactions. We chose the rock inhabitant Knufia petricola of the Chaetothyriales as a model for developing methods for genetic manipulation. Here, we report on the expansion of the genetic toolkit by more efficient multiplex CRISPR/Cas9 using a plasmid-based system for expression of Cas9 and multiple sgRNAs and the implementation of the three resistance selection markers genR (geneticin/nptII), baR (glufosinate/bar), and suR (chlorimuron ethyl/sur). The targeted integration of expression constructs by replacement of essential genes for pigment synthesis allows for an additional color screening of the transformants. The black-pink screening due to the elimination of pks1 (melanin) was applied for promoter studies using GFP fluorescence as reporter. The black-white screening due to the concurrent elimination of pks1 and phs1 (carotenoids) allows to identify transformants that contain the two expression constructs for co-localization or bimolecular fluorescence complementation (BiFC) studies. The co-localization and interaction of the two K. petricola White Collar orthologs were demonstrated. Two intergenic regions (igr1, igr2) were identified in which expression constructs can be inserted without causing obvious phenotypes. Plasmids of the pNXR-XXX series and new compatible entry plasmids were used for fast and easy generation of expression constructs and are suitable for a broad implementation in other fungi. This variety of genetic tools is opening a completely new perspective for mechanistic and very detailed study of expression, functioning and regulation of the genes/proteins encoded by the genomes of black fungi.
KW - Microcolonial fungi
KW - DHN melanin
KW - Cloning vectors
KW - Genetics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546192
DO - https://doi.org/10.3389/ffunb.2022.862429
SN - 2673-6128
VL - 3
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ruibal, C.
A1 - Gueidan, C.
A1 - Selbmann, L.
A1 - Gorbushina, Anna
A1 - Crous, P.W.
A1 - Groenewald, J.Z.
A1 - Muggia, L.
A1 - Grube, M.
A1 - Isola, D.
A1 - Schoch, C.L.
A1 - Staley, J.T.
A1 - Lutzoni, F.
A1 - De Hoog, G.S.
T1 - Phylogeny of rock-inhabiting fungi related to Dothideomycetes
N2 - The class Dothideomycetes (along with Eurotiomycetes) includes numerous rock-inhabiting fungi (RIF), a group of ascomycetes that tolerates surprisingly well harsh conditions prevailing on rock surfaces. Despite their convergent morphology and physiology, RIF are phylogenetically highly diverse in Dothideomycetes. However, the positions of main groups of RIF in this class remain unclear due to the lack of a strong phylogenetic framework. Moreover, connections between rock-dwelling habit and other lifestyles found in Dothideomycetes such as plant pathogens, saprobes and lichen-forming fungi are still unexplored. Based on multigene phylogenetic analyses, we report that RIF belong to Capnodiales (particularly to the family Teratosphaeriaceae s.l.), Dothideales, Pleosporales, and Myriangiales, as well as some uncharacterised groups with affinities to Dothideomycetes. Moreover, one lineage consisting exclusively of RIF proved to be closely related to Arthoniomycetes, the sister class of Dothideomycetes. The broad phylogenetic amplitude of RIF in Dothideomycetes suggests that total species richness in this class remains underestimated. Composition of some RIF-rich lineages suggests that rock surfaces are reservoirs for plant-associated fungi or saprobes, although other data also agree with rocks as a primary substrate for ancient fungal lineages. According to the current sampling, long distance dispersal seems to be common for RIF. Dothideomycetes lineages comprising lichens also include RIF, suggesting a possible link between rock-dwelling habit and lichenisation.
KW - Arthoniomycetes
KW - Capnodiales
KW - Dothideomycetes
KW - Evolution
KW - Extremotolerance
KW - Multigene phylogeny
KW - Rock-inhabiting fungi
PY - 2009
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-219821
DO - https://doi.org/10.3114/sim.2009.64.06
SN - 0166-0616
VL - 64
IS - 1
SP - 123
EP - 133
PB - Centraalbureau voor Schimmelcultures
CY - Utrecht, The Netherlands
AN - OPUS4-21982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gerrits, Ruben
A1 - Pokharel, R.
A1 - Breitenbach, Romy
A1 - Radnik, Jörg
A1 - Feldmann, Ines
A1 - Schuessler, J.A.
A1 - von Blanckenburg, F.
A1 - Gorbushina, Anna
A1 - Schott, J.
T1 - How the rock-inhabiting fungus K. petricola A95 enhances olivine dissolution through attachment
N2 - Free-living and mycorrhizal fungi are able to enhance the weathering of rock and other solid substrates. Deciphering the exact mechanisms of these natural processes requires their experimental simulation. Moreover, by performing these simulations with genetically amenable rock-weathering fungi, one can knock-out certain fungal traits and consequently identify their weathering-relevant function. Here, the effect of the rock-inhabiting fungus, Knufia petricola A95, on the dissolution kinetics of an Fe-bearing olivine (Mg1.86Fe0.19SiO4) is investigated at 25 °C and pH 6 using reproducible batch and mixed flow experiments. The availability of a melanin-deficient mutant (ΔKppks) of K. petricola A95, which produces more extracellular polymeric substances (EPS) than the wild type (WT), enables the comparative study of the role of melanin and EPS in olivine dissolution. In abiotic dissolution experiments, the olivine dissolution rate decreased considerably over time at pH 6 but not at pH 3.5. This inhibition of abiotic olivine dissolution at pH 6 was most likely caused by the in-situ oxidation of ferrous Fe and/or the precipitation of ferric hydroxides at the olivine surface. In corresponding biotic experiments at pH 6, both the wild type K. petricola and its melanin-deficient mutant ΔKppks solubilised and bound significant amounts of Fe released by olivine dissolution. Fe oxidation and precipitation were thus prevented and olivine dissolution proceeded faster than in the abiotic experiments. By sequestering Fe directly at the olivine surface, the attached wild type K. petricola cells were particularly efficient at preventing the oxidation of Fe at the mineral surface: the slowdown of olivine dissolution almost completely disappeared. The attachment capacity of these wild type cells is most likely mediated by wild type-specific EPS. Our presented experimental systems allow the oxidation of mineral-released Fe and include a rock-inhabiting fungus, thus simulating chemical, physical and biological conditions that set dissolution rates in a way that is relevant to natural ecosystems.
KW - Black fungi
KW - Bio-weathering
KW - Forsterite
KW - Knock-out mutant
KW - Extracellular polymeric substances
KW - Melanin Adhesion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509332
DO - https://doi.org/10.1016/j.gca.2020.05.010
VL - 282
SP - 76
EP - 97
PB - Elsevier Ltd.
AN - OPUS4-50933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diener, S.
A1 - Schubert, Hendrik
A1 - Held, A.
A1 - Katsikis, N.
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Influence of the dispersant on the parts quality in slurry-based binder jetting of SiC ceramics
N2 - Binder jetting is establishing more and more in the ceramic industry to produce large complex shaped parts. A parameter with a great impact on the quality of the parts is the binder–powder interaction. The use of ceramic slurries as feedstock for this process, such as in the layerwise slurry deposition–print technology, allows a great flexibility in the composition. Such slurries are typically composed of ceramic powder, water, and small amounts of various additives. The understanding of the effect of these components on the printing quality is thus essential for the feedstock development. Four models were developed regarding the impact of additives, such as dispersants on printing. These models were confirmed or rebutted by experiments performed for an SiC slurry system with two different concentrations of a dispersant and a commercial phenolic resin used as a binder. It is shown that for this system the influence of the dispersant on the curing behavior and the clogging of the pores by dispersant can be neglected. The redispersion of the dispersant after the curing of the resin has no or only a minor effect. However, the wetting behavior determined by the surface energies of the system seem to be most crucial. In case the surface energy of the slurry additive is significantly lower than the surface energy of the binder, the strength of the green parts and the printing quality will be low. This was shown by inverse gas chromatography, contact angle measurement, rheological characterization, and mechanical tests with casted samples.
KW - Additive Manufacturing
KW - Binder Jetting
KW - Layerwise slurry deposition
KW - Silicon carbide
KW - Wetting
PY - 2022
DO - https://doi.org/10.1111/jace.18693
SN - 1551-2916
VL - 2022
SP - 1
EP - 15
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-55542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munasir,
A1 - Triwikantoro,
A1 - Zainuri, M.
A1 - Bäßler, Ralph
A1 - Darminto,
T1 - Mechanical Strength and Corrosion Rate of Aluminium Composites (Al/SiO2): Nanoparticle Silica (NPS) as Reinforcement
N2 - The fabrication and characteristics of amorphous silica reinforced Al matrix composites are studied in this paper. The major starting materials were commercial Al powder and extracted nanoparticle SiO2 (NPS) powder from Indonesian silica sands. Two different active solutions,namely N-butanol and tetramethylammonium hydroxide (TMAH), were introduced during synthesis. Characterisations in terms of physical, mechanical, microstructural and corrosion rate examinations were also employed. Introducing the SiO2 nanoparticles into the Al matrix has decreased the density and increased the porosity of the composites. The addition of N-butanol into Al/SiO2(Al/SiO2(B)) led to broader and lower X-ray diffraction profiles than the addition of TMAH (Al/SiO2(T)). From the microstructural analysis, we found that the SiO2 particles enter and agglomerate into the opening gap of the Al sheets. Furthermore, yield strength, ultimate compression strength and modulus of elasticity tended to reduce the addition of SiO2. The corrosion rate of Al/SiO2(T) was lower than that of Al/SiO2(B) composites.
KW - Aluminium
KW - Silica
KW - Al/SiO2 composite
KW - Mechanical strength
KW - Corrosion rate
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487185
DO - https://doi.org/10.21315/jps2019.30.1.7
SN - 1675-3402
SN - 2180-4230
VL - 30
IS - 1
SP - 81
EP - 97
PB - USM Press
CY - Pulau Pinang, Malaysia
AN - OPUS4-48718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brusamarello-Santos, L. C. C.
A1 - Alberton, D.
A1 - Valdameri, G.
A1 - Camilios-Neto, D.
A1 - Covre, R.
A1 - Lopes, K. d. P.
A1 - Zibetti Tadra-Sfeir, M.
A1 - Faoro, H.
A1 - Adele Monteiro, R.
A1 - Barbosa-Silva, A.
A1 - Broughton, William John
A1 - Oliveira Pedrosa, F.
A1 - Wassem, R.
A1 - de Souza, E.M.
T1 - Modulation of defence and iron homeostasis genes in rice roots by the diazotrophic endophyte Herbaspirillum seropedicae
N2 - Rice is staple food of nearly half the world’s population. Rice yields must therefore increase to feed ever larger populations. By colonising rice and other plants, Herbaspirillum spp. stimulate plant growthand productivity. However the molecular factors involved are largely unknown. To further explore this interaction, the transcription profiles of Nipponbare rice roots inoculated with Herbaspirillum seropedicae were determined by RNA-seq. Mapping the 104 million reads against the Oryza sativa cv. Nipponbare genome produced 65 million unique mapped reads that represented 13,840 transcripts each with at least two-times coverage. About 7.4% (1,014) genes were differentially regulated and of these 255 changed expression levels more than two times. Several of the repressed genes encoded proteins related to plant defence (e.g. a putative probenazole inducible protein), plant disease resistance as well as enzymes involved in flavonoid and isoprenoid synthesis. Genes related to the synthesis and efflux of phytosiderophores (PS) and transport of PS-iron complexes were induced by the bacteria. These data suggest that the bacterium represses the rice defence system while concomitantly activating iron uptake. Transcripts of H. seropedicae were also detected amongst which transcripts of genes involved in nitrogen fixation, cell motility and cell wall synthesis were the most expressed.
KW - Herbaspirillum seropedicae
KW - Pathogen
KW - Rice
KW - qPCR
KW - Genome
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-490122
DO - https://doi.org/10.1038/s41598-019-45866-w
SN - 2045-2322
VL - 9
SP - 10573-1
EP - 10573-15
PB - Nature
CY - London
AN - OPUS4-49012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seiffert, Franz
A1 - Bandow, Nicole
A1 - Kalbe, Ute
A1 - Milke, R.
A1 - Gorbushina, Anna
T1 - Laboratory tools to quantify biogenic dissolution of rocks and minerals: a model rock biofilm growing in percolation columns
N2 - Sub-aerial biofilms (SAB) are ubiquitous, self-sufficient microbial ecosystems found on mineral surfaces at all altitudes and latitudes. SABs, which are the principal causes of weathering on exposed terrestrial surfaces, are characterized by patchy growth dominated by associations of algae, cyanobacteria, fungi and heterotrophic bacteria. A recently developed in vitro system to study colonization of rocks exposed to air included two key SAB participants - the rock-inhabiting ascomycete Knufia petricola (CBS 123872) and the phototrophic cyanobacterium Nostoc punctiforme ATCC29133. Both partners are genetically tractable and we used them here to study weathering of granite, K-feldspar and plagioclase. Small fragments of the various rocks or minerals (1–6 mm) were packed into flow-through columns and incubated with 0.1% glucose and 10 μM thiamine-hydrochloride (90 μL min−1) to compare weathering with and without biofilms. Dissolution of the minerals was followed by: (i) analysing the degradation products in the effluent from the columns via Inductively Coupled Plasma Spectroscopy and (ii) by studying polished sections of the incubated mineral fragments/grains using scanning electron microscopy, transmission electron microscopy and energy dispersive X-ray analyses. K. petricola/N. punctiforme stimulated release of Ca, Na, Mg and Mn. Analyses of the polished sections confirmed depletion of Ca, Na and K near the surface of the fragments. The abrupt decrease in Ca concentration observed in peripheral areas of plagioclase fragments favored a dissolution-reprecipitation mechanism. Percolation columns in combination with a model biofilm can thus be used to study weathering in closed systems. Columns can easily be filled with different minerals and biofilms, the effluent as well as grains can be collected after long-term exposure under axenic conditions and easily analyzed.
KW - Biotic weathering
KW - Flow-through columns
KW - Plagioclase
KW - K-feldspar
KW - Granite
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373395
DO - https://doi.org/10.3389/feart.2016.00031
SN - 2296-6463
VL - 4
SP - Article 31, 1
EP - 10
PB - Frontiers in Earth Science
CY - Lausanne
AN - OPUS4-37339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menzel, Friederike
A1 - Conradi, Bianca
A1 - Rodenacker, K.
A1 - Gorbushina, Anna
A1 - Schwibbert, Karin
ED - Menzel, Friederike
T1 - Flow chamber system for the statistical evaluation of bacterial colonization on materials
N2 - Biofilm formation on materials leads to high costs in industrial processes, as well as in medical applications. This fact has stimulated interest in the development of new materials with improved surfaces to reduce bacterial colonization. Standardized tests relying on statistical evidence are indispensable to evaluate the quality and safety of these new materials. We describe here a flow chamber system for biofilm cultivation under controlled conditions with a total capacity for testing up to 32 samples in parallel. In order to quantify the surface colonization, bacterial cells were DAPI (4‘,6-diamidino-2-phenylindole)-stained and examined with epifluorescence microscopy. More than 100 images of each sample were automatically taken and the surface coverage was estimated using the free open source software g’mic, followed by a precise statistical evaluation. Overview images of all gathered pictures were generated to dissect the colonization characteristics of the selected model organism Escherichia coli W3310 on different materials (glass and implant steel). With our approach, differences in bacterial colonization on different materials can be quantified in a statistically validated manner. This reliable test procedure will support the design of improved materials for medical, industrial, and environmental (subaquatic or subaerial) applications.
KW - Subaerial and subaquatic biofilm
KW - Escherichia coli
KW - Image analysis
KW - Microscopy
KW - Biofilm
KW - Biofouling
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377040
DO - https://doi.org/10.3390/ma9090770
SN - 1996-1944
VL - 9
IS - 9
SP - 770
AN - OPUS4-37704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Wirth, Cynthia
A1 - Mühler, T.
A1 - Günster, Jens
T1 - Powder-bed stabilization for powder-based additive manufacturing
N2 - The most successful additive manufacturing (AM) technologies are based on the layer-by-layer deposition of a flowable powder. Although considered as the third industrial revolution, one factor still limiting these processes to become completely autonomous is the often necessary build-up of support structures. Besides the prevention of lateral shifts of the part during the deposition of layers, the support assures quality and stability to the built process. The loose powder itself surrounding the built object, or so-called powder-bed, does not provide this sustenance in most existent technology available. Here we present a simple but effective and economical method for stabilizing the powder-bed, preventing distortions in the geometry with no need for support structures. This effect, achieved by applying an air flow through the powder-bed, is enabling an entirely autonomous generation of parts and is a major contribution to all powder-based additive manufacturing technologies. Moreover, it makes powder-based AM independent of gravitational forces, which will facilitate crafting items in space from a variety of powdery materials.
KW - Additive manufacturing
KW - Powder bed
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314244
DO - https://doi.org/10.1155/2014/491581
SN - 1687-8132
SN - 1687-8140
N1 - Geburtsname von Wirth, Cynthia: Gomes, C. M. - Birth name of Wirth, Cynthia: Gomes, C. M.
VL - 2014
SP - 491581-1 - 491581-6
PB - Hindawi Publishing Corporation
CY - New York, NY ; Cairo
AN - OPUS4-31424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lopez-Heredia, M.A.
A1 - Gildenhaar, Renate
A1 - Berger, Georg
A1 - Linow, Ulf
A1 - Wirth, Cynthia
A1 - Günster, Jens
A1 - Houshmand, A.
A1 - Stiller, M.
A1 - Knabe-Ducheyne, C.
T1 - Effect of stressed and unstressed cell culture environments on the viability of MC3T3 cells with calcium phosphates
T2 - ISACB-6 - International symposium on apatite and correlative biomaterials
CY - Nantes, France
DA - 2013-06-05
KW - Cell culture media
KW - Fetal bovine serum
KW - Stressed
KW - Unstressed
KW - Calcium alkaline orthophosphates
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-299387
DO - https://doi.org/10.4172/2090-5025.S1-002
SN - 2090-5017
SN - 2090-5025
N1 - Geburtsname von Wirth, Cynthia: Gomes, C. M. - Birth name of Wirth, Cynthia: Gomes, C. M.
SP - 1
EP - 3(?)
PB - Ashdin
AN - OPUS4-29938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C., Ruibal
A1 - L., Selbmann
A1 - Serap, Avci
A1 - Martin-Sanchez, Pedro Maria
A1 - Gorbushina, Anna
ED - Gorbushina, Anna
T1 - Roof-Inhabiting Cousins of Rock-Inhabiting Fungi: Novel Melanized Microcolonial Fungal Species from Photocatalytically Reactive Subaerial Surfaces
N2 - Subaerial biofilms (SAB) are an important factor in weathering, biofouling, and biodeterioration of bare rocks, building materials, and solar panel surfaces. The realm of SAB is continually widened by modern materials, and the settlers on these exposed solid surfaces always include melanized, stress-tolerant microcolonial ascomycetes. After their first discovery on desert rock surfaces, these melanized chaetothyrialean and dothidealean ascomycetes have been found on Mediterranean monuments after biocidal treatments, Antarctic rocks and solar panels. New man-made modifications of surfaces (e.g., treatment with biocides or photocatalytically active layers) accommodate the exceptional stress-tolerance of microcolonial fungi and thus further select for this well-protected ecological group. Melanized fungal strains were isolated from a microbial community that developed on highly photocatalytic roof tiles after a long-term environmental exposure in a maritime-influenced region in northwestern Germany. Four of the isolated strains are described here as a novel species, Constantinomyces oldenburgensis, based on multilocus ITS, LSU, RPB2 gene phylogeny. Their closest relative is a still-unnamed rock-inhabiting strain TRN431, here described as C. patonensis. Both species cluster in Capnodiales, among typical melanized microcolonial rock fungi from different stress habitats, including Antarctica. These novel strains flourish in hostile conditions of highly oxidizing material surfaces, and shall be used in reference procedures in material testing.
KW - Microcolonial fungi
KW - Multilocus phylogeny
KW - Photocatalytic surfaces
KW - Subaerial biofilms
KW - Stress tolerance
KW - Constantinomyces
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-455182
DO - https://doi.org/10.3390/life8030030
VL - 8
IS - 3
SP - 30
EP - 44
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-45518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Lüchtenborg, Jörg
A1 - Mühler, T.
A1 - Wilbig, Janka
A1 - Mohr, Gunther
A1 - Villatte, T.
A1 - Léonard, Fabien
A1 - Nolze, Gert
A1 - Sparenberg, M.
A1 - Melcher, J.
A1 - Hilgenberg, Kai
A1 - Günster, Jens
T1 - Enabling the 3D Printing of Metal Components in μ-Gravity
N2 - As humanity contemplates manned missions to Mars, strategies need to be developed for the design and operation of hospitable environments to safely work in space for years. The supply of spare parts for repair and replacement of lost equipment will be one key need, but in-space manufacturing remains the only option for a timely supply. With high flexibility in design and the ability to manufacture ready-to-use components directly from a computeraided model, additive manufacturing (AM) technologies appear extremely attractive. For the manufacturing of metal parts, laser-beam melting is the most widely used AM process. However, the handling of metal powders in the absence of gravity is one prerequisite for its successful application in space. A gas flow throughout the powder bed is successfully applied to compensate for missing gravitational forces in microgravity experiments. This so-called gas-flow-assisted powder deposition is based on a porous Building platform acting as a filter for the fixation of metal particles in a gas flow driven by a pressure difference maintained by a vacuum pump.
KW - Additive manufacturing
KW - µ-gravity
KW - Laser beam melting
KW - Parabolic flight
KW - 3D printing
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492190
DO - https://doi.org/10.1002/admt.201900506
SP - 1900506
PB - WILEY-VCH Verlag GmbH
AN - OPUS4-49219
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
T1 - On the corrosion mechanism of CO2 transport pipeline steel caused by condensate: Synergistic effects of NO2 and SO2
N2 - To study the effects of condensed acid liquid, hereafter referred to as condensate, on the CO2 transport pipeline steels, gas mixtures containing a varying concentration of H2O, O2, NO2, and SO2, were proposed and resulted in the condensate containing H2SO4 and HNO3 with the pH ranging from 0.5 to 2.5. By exposing the pipeline steel to the synthetic condensate with different concentration of acidic components, the corrosion kinetic is significantly changed. Reaction kinetic was studied using electrochemical methods coupled with water analysis and compared with surface analysis (scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), and X-ray diffractometry (XRD)) of corroded coupons. The results showed that, although the condensation of NO2 in the form of HNO3 causes faster general corrosion rate, it is the condensation of SO2 in the form of H2SO4 or the combination of SO2 and NO2 that may cause much more severe problems in the form of localized and pitting corrosions. The resulting corrosion forms were depended on the chemical nature of acids and their concentration at the same investigated pH. The effects of changing CO2 flow rate and renewing condensate on pitting corrosion were further studied.
KW - Carbon capture, utilization and storage technology
KW - CCUS
KW - Corrosion
KW - Condensate
KW - Electrochemical characterisation
KW - Pitting corrosion
KW - Impurities
KW - Carbon steel
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473685
UR - https://www.mdpi.com/1996-1944/12/3/364
DO - https://doi.org/10.3390/ma12030364
SN - 1996-1944
VL - 12
IS - 3
SP - 364, 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-47368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nöller, Renate
A1 - Feldmann, Ines
A1 - Kasztovszky, Z.
A1 - Szőkefalvi-Nagy, Z.
A1 - Kovács, I.
T1 - Characteristic Features of Lapis Lazuli from Different Provenances, Revised by µXRF, ESEM, PGAA and PIXE
N2 - The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending on the quantity of samples analysed from a specific geological region and the methods applied. In order to provide evidence, a multi-technique analytical approach using µXRF, ESEM, PGAA and PIXE is applied to samples from the most famous deposits of lapis lazuli. Special elements determined as fingerprints are compared in relation to the forming conditions obvious in textural features. The results and statistical output allow a differentiation that enables an optimized local classification of the blue stone. An absolute requirement for all geo-tracing performed on blue colored cultural objects of unknown provenance is awareness of the limits of analysis. The possible sources of lapis lazuli are tested by analysing the blue pigment used as paint on murals and ink on manuscripts from the Silk Road.
KW - Lapis lazuli
KW - Micro-XRF
KW - ESEM
KW - PGAA
KW - PIXE
KW - Pigment analyses
KW - Provenance studies
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491181
DO - https://doi.org/10.17265/2328-2193/2019.02.003
SN - 2328-2193
VL - 7
IS - 2
SP - 57
EP - 69
PB - David
CY - New York, NY
AN - OPUS4-49118
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hampel, Marco
A1 - Schenderlein, Matthias
A1 - Schary, Christian
A1 - Dimper, Matthias
A1 - Özcan Sandikcioglu, Özlem
T1 - Efficient detection of localized corrosion processes on stainless steel by means of scanning electrochemical microscopy (SECM) using a multi-electrode approach
N2 - High resolution analysis of corrosion processes on stainless steels is a challenging task. The application of local electrochemical techniques such as scanning electrochemical microscopy (SECM) has opened new possibilities for the detection of corrosion products and activity on metallic surfaces. However, due to its stochastic nature, the analysis of pitting corrosion requires being at the right place at the right time. Scanning over large areas at a high resolution not only leads to long scan durations but also leaves many short-lived processes undetected. In this paper we present the combined automated operation of SECM and wire multi-electrodes connected to a multi-electrode analyzer (MMA). The inter-electrode currents between 25 wire electrodes connected via zero resistance ammeters (ZRA) are measured by the MMA at open circuit potential (OCP) and the electrodes reporting anodic currents are detected automatically to be analyzed by means of SECM. The results demonstrate the successful application of this methodology for the detection of unstable and stable pitting processes on 304 stainless steel in a corrosive aqueous environment.
KW - Scanning electrochemical microscope (SECM)
KW - Localised corrosion
KW - Corrosion monitoring
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-478646
DO - https://doi.org/10.1016/j.elecom.2019.02.019
VL - 101
SP - 52
EP - 55
PB - Elsevier B.V.
AN - OPUS4-47864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dantas, A.
A1 - Scalabrin, D.
A1 - Farias, R.
A1 - Barbosa, A. A.
A1 - Ferraz, A.
A1 - Wirth, Cynthia
T1 - Design of highly porous hydroxyapatite scaffolds by conversion of 3D printed gypsum structures – a comparison study
N2 - Hydroxyapatite (HA) is a bioceramic material with excellent biological properties. However, these properties are strongly dependent of ist crystallinity degree, with high values of crystallinity associated to poor resorption rates and bioactivity. This work evaluates the properties of HA samples produced by two different free-forming conformation methods, CNC machining and 3D printing. In both cases, porous gypsum samples were produced and subsequently converted into HA in a reaction with di-ammonium hydrogen phosphate at 100°C and pH 8. A total conversion of the samples was achieved after 36 h independently of the conformation method used. The microstructure, however, before and after the conversion is showed to be dependent on the method used. After conversion the machined samples achieved a Maximum compressive strength of 3.5 MPaforporosities of circa 80%, while 3D printed samples achieved a tensile strength of 2.0 MPa by porosities of 61%.
T2 - The Second CIRP Conference on Biomanufacturing
CY - Manchester Conference Centre, UK
DA - July 29, 2015
KW - Additive manufacturing
KW - 3D printing
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-400831
DO - https://doi.org/10.1016/j.procir.2015.07.030
SN - 2212-8271
VL - 49
SP - 55
EP - 60
PB - Elsevier
AN - OPUS4-40083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Torge, Manfred
A1 - Feldmann, Ines
A1 - Günther, Tobias
A1 - Wilsch, Gerd
ED - Glaser, L.
T1 - Analytische Untersuchungen an Glasmalfarben mittels EDX und LIBS
N2 - Nach 1850 wurde zur weiteren Herabsetzung der Einbrenntemperatur von Glasmalfarben Borax (Na2B4O7 · 10 H2O) zugesetzt. Das Verhältnis war nun 1 Teil SiO2, 3 Teile PbO und 0,5 Teile Borax. Der analytische Nachweis von Bor in eingebrannten Malschichten war bisher jedoch nicht möglich.Daher wurden in Laborversuchen Glasmalfarben mit unterschiedlichem Gehalt an Borax auf Modellgläser aufgetragen, eingebrannt und anschließend unter simulierten Umweltbedingungen zeitraffend im Klimaschrank bewittert.
Mit Hilfe von elektronenmikroskopischen Untersuchungen können Malschichten charakterisiert werden und somit Hinweise auf mögliche Schadensursachen liefern. Erste Versuche zum Nachweis von Bor erfolgten mit Hilfe von LIBS-Messungen (Laser Induced Breakdown Spectroscopy) an im Labor hergestellten Glasmalfarben mit unterschiedlichem Boraxgehalt.
T2 - Archäometrie und Denkmalpflege 2018
CY - Hamburg, Germany
DA - 20.03.2018
KW - Glasmalfarben
KW - Umweltsimulation
KW - Analytik
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-450664
SN - 978-3-945931-16-5
DO - https://doi.org/10.3204/DESY-PROC-2018-01
SN - 1435-8077
SP - 283
EP - 285
PB - Deutsches Elektronen -Synchrotron
CY - Hamburg
AN - OPUS4-45066
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aristia, Gabriela
A1 - Le, Quynh Hoa
A1 - Nofz, Marianne
A1 - Sojref, Regine
A1 - Bäßler, Ralph
T1 - Study of Al2O3 Sol-Gel Coatings on X20Cr13 in Artificial North German Basin Geothermal Water at 150 °C
N2 - Al2O3 has been widely used as a coating in industrial applications due to its excellent chemical and thermal resistance. Considering high temperatures and aggressive mediums exist in geothermal systems, Al2O3 can be a potential coating candidate to protect steels in geothermal applications. In this study, γ-Al2O3 was used as a coating on martensitic steels by applying AlOOH sol followed by a heat treatment at 600 °C. To evaluate the coating application process, one-, two-, and three-layer coatings were tested in the artificial North German Basin (NGB), containing 166 g/L Cl−, at 150 °C and 1 MPa for 168 h. To reveal the stability of the Al2O3 coating in NGB solution, three-layer coatings were used in exposure tests for 24, 168, 672, and 1296 h, followed by surface and cross-section characterization. SEM images show that the Al2O3 coating was stable up to 1296 h of exposure, where the outer layer mostly transformed into boehmite AlOOH with needle-like crystals dominating the surface. Closer analysis of cross-sections showed that the interface between each layer was affected in long-term exposure tests, which caused local delamination after 168 h of exposure. In separate experiments, electrochemical impedance spectroscopy (EIS) was performed at 150 °C to evaluate the changes of coatings within the first 24 h. Results showed that the most significant decrease in the impedance is within 6 h, which can be associated with the electrolyte penetration through the coating, followed by the formation of AlOOH. Here, results of both short-term EIS measurements (up to 24 h) and long-term exposure tests (up to 1296 h) are discussed.
KW - Al2O3
KW - Geothermal
KW - Martensitic steels
KW - Behmite
KW - Corrosion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525551
DO - https://doi.org/10.3390/coatings11050526
SN - 2079-6412
VL - 11
IS - 5
SP - 526
PB - MDPI
CY - Basel
AN - OPUS4-52555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - An, Biwen Annie
A1 - Kleinbub, Sherin
A1 - Özcan Sandikcioglu, Özlem
A1 - Koerdt, Andrea
T1 - Iron to Gas: Versatile Multiport Flow-Column Revealed Extremely High Corrosion Potential by Methanogen-Induced Microbiologically Influenced Corrosion (Mi-MIC)
N2 - Currently, sulfate-reducing bacteria (SRB) is regarded as the main culprit of microbiologically influenced corrosion (MIC), mainly due to the low reported corrosion rates of other microorganisms. For example, the highest reported corrosion rate for methanogens is 0.065 mm/yr. However, by investigating methanogen-induced microbiologically influenced corrosion (Mi-MIC) using an in-house developed versatile multiport flow test column, extremely high corrosion rates were observed. We analyzed a large set of carbon steel beads, which were sectionally embedded into the test columns as substrates for iron-utilizing methanogen Methanobacterium IM1. After 14 days of operation using glass beads as fillers for section separation, the highest average corrosion rate of Methanobacterium IM1 was 0.2 mm/yr, which doubled that of Desulfovibrio ferrophilus IS5 and Desulfovibrio alaskensis 16109 investigated at the same conditions. At the most corroded region, nearly 80% of the beads lost 1% of their initial weight (fast-corrosion), resulting in an average corrosion rate of 0.2 mm/yr for Methanobacterium IM1-treated columns. When sand was used as filler material to mimic sediment conditions, average corrosion rates for Methanobacterium IM1 increased to 0.3 mm/yr (maximum 0.52 mm/yr) with over 83% of the beads having corrosion rates above 0.3 mm/yr. Scanning electron images of metal coupons extracted from the column showed methanogenic cells were clustered close to the metal surface. Methanobacterium IM1 is a hydrogenotrophic methanogen with higher affinity to metal than H2. Unlike SRB, Methanobacterium IM1 is not restricted to the availability of sulfate concentration in the environment. Thus, the use of the multiport flow column provided a new insight on the corrosion potential of methanogens, particularly in dynamic conditions, that offers new opportunities for monitoring and development of mitigation strategies. Overall, this study shows under certain conditions methanogenic archaea can cause higher corrosion than SRB, specific quantifications, i.e., maximum, average, and minimum corrosion rates can be determined, and that spatial statistical evaluations of MIC can be carried out.
KW - Microbiologically influenced corrosion
KW - Methanogen
KW - Methane
KW - Biocorrosion
KW - Flow system
KW - Modeling
KW - Multiport
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506084
DO - https://doi.org/10.3389/fmicb.2020.00527
VL - 11
SP - Article 527
PB - Frontiers in microbiology
AN - OPUS4-50608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aristia, Gabriela
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
T1 - Corrosion of Carbon Steel in Artificial Geothermal Brine: Influence of Carbon Dioxide at 70 °C and 150 °C
N2 - This study focuses on the corrosion mechanism of carbon steel exposed to an artificial geothermal brine influenced by carbon dioxide (CO2) gas. The tested brine simulates a geothermal source in Sibayak, Indonesia, containing 1500 mg/L of Cl-, 20 mg/L of SO4 2-, and 15 mg/L of HCO3-with pH 4. To reveal the temperature effect on the corrosion behavior of carbon steel, exposure and electrochemical tests were carried out at 70 °C and 150 °C. Surface analysis of corroded specimens showed localized corrosion at both temperatures, despite the formation of corrosion products on the surface. After 7 days at 150 °C, SEM images showed the formation of an adherent, dense, and crystalline FeCO3 layer. Whereas at 70 °C, the corrosion products consisted of chukanovite (Fe2(OH)2CO3) and siderite (FeCO3), which are less dense and less protective than that at 150 °C.
Control experiments under Ar-environment were used to investigate the corrosive effect of CO2. Free corrosion potential (Ecorr) and electrochemical impedance spectroscopy (EIS) confirm that at both temperatures, the corrosive effect of CO2 was more significant compared to that measured in the Ar-containing solution. In terms of temperature effect, carbon steel remained active at 70 °C, while at 150 °C, it became passive due to the FeCO3 formation. These results suggest that carbon steel is more susceptible to corrosion at the near ground surface of a geothermal well, whereas at a deeper well with a higher temperature, there is a possible risk of scaling (FeCO3 layer). A longer exposure test at 150 °C with a stagnant solution for 28 days, however, showed the unstable FeCO3 layer and therefore a deeper localized corrosion compared to that of seven-day exposed specimens.
KW - Carbon steel
KW - CO2
KW - Corrosion
KW - Electrochemical impedance spectroscopy
KW - Geothermal
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498168
DO - https://doi.org/10.3390/ma12223801
SN - 1996-1944
VL - 12
IS - 22
SP - 3801-1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-49816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Melo Bernardino, Raphael
A1 - Valentino, S.
A1 - Franchin, G.
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Manufacturing of ceramic components with internal channels by a novel additive/subtractive hybridizazion process
N2 - A new approach for fabrication of ceramic components with inner channels is proposed, as a result of the combination of two additive and one subtractive manufacturing processes. In this project, porcelain parts are manufactured by the Layerwise Slurry Deposition (LSD) process, meanwhile end milling and Direct Ink Writing (DIW) are applied to create channels on the surface of the deposited ceramic. Unique to the LSD process is the Formation of a freestanding powder bed with a mechanical strength comparable to conventional slip casted ceramic green bodies. Combining these three processes allows the manufacturing of ceramic objects containing an internal path of ink, which in this case was a graphite-based ink that can be further eliminated by heat treatment to obtain a porcelain object embedded with channels. The results show the capabilities of this method and its potential to fabricate not only parts with inner channels, but also multi-material and multi-functional components (such as integrated electronic circuits).
KW - Additive Manufacturing
KW - Layerwise Slurry Deposition
KW - Hybrid Manufacturing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510012
UR - https://www.sciencedirect.com/science/article/pii/S2666539520300109?via%3Dihub
DO - https://doi.org/10.1016/j.oceram.2020.100010
VL - 2
SP - 100010
PB - Elsevier Ltd.
AN - OPUS4-51001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Le, Quynh Hoa
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
A1 - Buggisch, E.
A1 - Schiller, Bernadette Nicole
A1 - Beck, M.
T1 - Corrosion Study on Wellbore Materials for the CO2 Injection Process
N2 - For reliability and safety issues of injection wells, corrosion resistance of materials used needs to be determined. Herein, representative low-cost materials, including carbon steel X70/1.8977 and low alloyed steel 1.7225, were embedded in mortar to mimic the realistic casing-mortar interface. Two types of cement were investigated: (1) Dyckerhoff Variodur commercial Portland cement, representing a highly acidic resistant cement and (2) Wollastonite, which can react with CO2 and become stable under a CO2 stream due to the carbonation process. Exposure tests were performed under 10 MPa and at 333 K in artificial aquifer fluid for up to 20 weeks, revealing crevice corrosion and uniform corrosion instead of expected pitting corrosion. To clarify the role of cement, simulated pore water was made by dispersing cement powder in aquifer fluid and used as a solution to expose steels. Surface analysis, accompanied by element mapping on exposed specimens and their crosssections, was carried out to trace the chloride intrusion and corrosion process that followed.
KW - Carbon capture storage
KW - CCS
KW - Carbon dioxide
KW - Corrosion
KW - Carbon steel
KW - Aquifer fluid
KW - Cement
KW - Casing
KW - Pitting
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519774
DO - https://doi.org/10.3390/pr9010115
SN - 2227-9717
VL - 9
IS - 1
SP - 115
PB - MDPI
CY - Basel
AN - OPUS4-51977
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Schütter, J. D.
A1 - Wagner, R.
A1 - Dimper, M.
A1 - Lützenkirchen-Hecht, D.
A1 - Özcan Sandikcioglu, Özlem
T1 - Trained to corrode: Cultivation in the presence of Fe(III) increases the electrochemical activity of iron reducing bacteria – An in situ electrochemical XANES study
N2 - This paper reports results from in situ electrochemical X-ray absorption near-edge spectroscopy (XANES) studies of the corrosion processes on model thin iron films in the presence of iron reducing bacteria Shewanella putrefaciens. Here we investigate the electrochemical activity of two cultures grown in the presence and absence of Fe(III) citrate in the culture medium. The XANES spectra and the OCP data of the Fe sample incubated with the culture grown in absence of Fe(III) did not show any significant changes during twenty hours of monitoring. In the case of the culture grown in Fe(III) containing medium, an accelerated dissolution of the iron film was observed together with the formation of a mixed Fe(II)-Fe(III) hydroxide surface layer. The open circuit potential (OCP) steadily approached the free corrosion potential of iron in neutral chloride containing electrolytes, indicating a continuous dissolution process without passivation.
KW - Microbiologically influenced corrosion
KW - XANES
KW - Electrochemistry
KW - Iron reducing bacteria
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505732
DO - https://doi.org/10.1016/j.elecom.2020.106673
VL - 112
SP - 106673
PB - Elsevier B.V.
AN - OPUS4-50573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stier, S. P.
A1 - Kreisbeck, C.
A1 - Ihssen, H.
A1 - Popp, M. A.
A1 - Hauch, J.
A1 - Malek, K.
A1 - Reynaud, M.
A1 - Goumans, T.P.M.
A1 - Carlsson, J.
A1 - Todorov, I.
A1 - Gold, L.
A1 - Räder, A.
A1 - Wenzel, W.
A1 - Bandesha, S. T.
A1 - Jacques, P.
A1 - Garcia‐Moreno, F.
A1 - Arcelus, O.
A1 - Friederich, P.
A1 - Clark, S.
A1 - Maglione, M.
A1 - Laukkanen, A.
A1 - Castelli, I. E.
A1 - Carrasco, J.
A1 - Cabanas, M. C.
A1 - Stein, H. S.
A1 - Özcan Sandikcioglu, Özlem
A1 - Elbert, D.
A1 - Reuter, K.
A1 - Scheurer, C.
A1 - Demura, M.
A1 - Han, S. S.
A1 - Vegge, T.
A1 - Nakamae, S.
A1 - Fabrizio, M.
A1 - Kozdras, M.
T1 - Materials Acceleration Platforms (MAPs) Accelerating Materials Research and Development to Meet Urgent Societal Challenges
N2 - AbstractClimate Change and Materials Criticality challenges are driving urgent responses from global governments. These global responses drive policy to achieve sustainable, resilient, clean solutions with Advanced Materials (AdMats) for industrial supply chains and economic prosperity. The research landscape comprising industry, academe, and government identified a critical path to accelerate the Green Transition far beyond slow conventional research through Digital Technologies that harness Artificial Intelligence, Smart Automation and High Performance Computing through Materials Acceleration Platforms, MAPs. In this perspective, following the short paper, a broad overview about the challenges addressed, existing projects and building blocks of MAPs will be provided while concluding with a review of the remaining gaps and measures to overcome them.
KW - Advanced materials
KW - Artificial intelligence
KW - Autonomous labs
KW - Materials acceleration platforms
KW - Societal challenges
KW - MAPs
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611583
DO - https://doi.org/10.1002/adma.202407791
SP - 1
EP - 26
PB - Wiley
AN - OPUS4-61158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voigt, Oliver
A1 - Knabe, Nicole
A1 - Nitsche, Sarah
A1 - Erdmann, Eileen
A1 - Schumacher, Julia
A1 - Gorbushina, Anna
T1 - An advanced genetic toolkit for exploring the biology of the rock‑inhabiting black fungus Knufia petricola
N2 - Microcolonial black fungi are a group of ascomycetes that exhibit high stress tolerance, yeast-like growth and constitutive melanin formation. They dominate a range of hostile natural and man-made environments, from desert rocks and salterns to dishwashers, roofs and solar panels. Due to their slow growth and a lack of genetic tools, the underlying mechanisms of black fungi’s phenotypic traits have remained largely unexplored. We chose to address this gap by genetically engineering the rock-inhabiting fungus Knufia petricola (Eurotiomycetes, Chaetothyriales), a species that exhibits all characteristics of black fungi. A cell biological approach was taken by generating K. petricola strains expressing green or red fluorescent protein variants. By applying: (1) traditional gene replacement; (2) gene editing and replacement via plasmid-based or ribonucleoprotein (RNP)-based CRISPR/Cas9, and (3) silencing by RNA interference (RNAi), we constructed mutants in the pathways leading to melanin, carotenoids, uracil and adenine. Stable single and double mutants were generated with homologous recombination (HR) rates up to 100%. Efficient, partially cloning-free strategies to mutate multiple
genes with or without resistance cassettes were developed. This state-of-the-art genetic toolkit, together with the annotated genome sequence of strain A95, firmly established K. petricola as a model for exploring microcolonial black fungi.
KW - Subaerial biofilms
KW - Biodeterioration
KW - Fluorescent microscopy
KW - CRISPR/Cas9
KW - RNA interference
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518601
DO - https://doi.org/10.1038/s41598-020-79120-5
VL - 10
IS - 1
SP - 22021
PB - Springer Nature
AN - OPUS4-51860
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kratzig, A.
A1 - Le, Quynh Hoa
A1 - Bettge, Dirk
A1 - Menneken, M.
A1 - Bäßler, Ralph
T1 - Early Stage of Corrosion Formation on Pipeline Steel X70 Under Oxyfuel Atmosphere at Low Temperature
N2 - The early stage of corrosion formation on X70 pipeline steel under oxyfuel atmosphere was investigated by applying a simulated gas mixture (CO2 containing 6700 ppmv O2, 100 ppmv NO2, 70 ppmv SO2 and 50 ppmv H2O) for 15 h at 278 K and ambient pressure. Short-term tests (6 h) revealed that the corrosion starts as local spots related to grinding marks progressing by time and moisture until a closed layer was formed. Acid droplets (pH 1.5), generated in the gas atmosphere, containing a mixture of H2SO4 and HNO3, were identified as corrosion starters. After 15 h of exposure, corrosion products were mainly X-ray amorphous and only partially crystalline. In-situ energy-dispersive X-ray diffraction (EDXRD) results showed that the crystalline fractions consist primarily of water-bearing iron sulfates. Applying Raman spectroscopy, water-bearing iron nitrates were detected as subordinated phases. Supplementary long-term tests exhibited a significant increase in the crystalline fraction and formation of additional water-bearing iron sulfates. All phases of the corrosion layer were intergrown in a nanocrystalline network. In addition, numerous globular structures have been detected above the corrosion layer, which were identified as hydrated iron sulphate and hematite. As a type of corrosion, shallow pit formation was identified, and the corrosion rate was about 0.1 mma−1. In addition to in-situ EDXRD, SEM/EDS, TEM, Raman spectroscopy and interferometry were used to chemically and microstructurally analyze the corrosion products.
KW - Corrosion
KW - CCUS
KW - In-situ ED-XRD
KW - CO2 pipeline transport
KW - Oxyfuel
KW - Carbon steel
KW - Impurities
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506303
DO - https://doi.org/10.3390/pr8040421
SN - 2227-9717
VL - 8
IS - 4
SP - 421-1
EP - 421-19
PB - MDPI
CY - Basel
AN - OPUS4-50630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mitova, M.
A1 - Iliev, M.
A1 - Nováková, A.
A1 - Gorbushina, Anna
A1 - Groudeva, V.I.
A1 - Martin-Sanchez, Pedro Maria
T1 - Diversity and biocide susceptibility of fungal assemblages dwelling in the Art Gallery of Magura Cave, Bulgaria
N2 - Magura Cave, north-western Bulgaria, possesses valuable rock-art paintings made with bat guano and dated from the period between the Eneolithic and Bronze Ages. Since 2008, the Art Gallery is closed to the general public in order to protect the paintings from vandalism, microclimatic changes caused by visitors and artificial illumination, and the consequent growth of fungi and phototrophs. Nevertheless, some tourist visits are allowed under the supervision of cave managers. This study provides the first scientific report on cultivable fungal assemblages dwelling different substrata in the Art Gallery. A total of 78 strains, belonging to 37 OTUs (Ascomycota 81%, Zygomycota 13%, Basidiomycota 5%), were isolated in the study. This fungal diversity was clearly dominated by Penicillium (50% of strains) and Aspergillus (13%). The most relevant visible fungal colonies were detected in sediments rich in bat guano, where, besides Penicillium, other guanophilic fungi such as Mucor, Mortierella, Trichosporon and Trichoderma were dominant. Conversely, scarce fungi were detected on rock surface of painted walls. Based on the biocide susceptibility assay, octylisothiazolinone (OIT) and benzalkonium chloride (BAC) were effective inhibiting the in vitro growth of dominant fungal species in Magura Cave, when applied at concentrations ranged from 100 to 1,000 mg/L. These data provide a valuable knowledge about Magura fungi, and exemplify a type of preliminary test that may be conducted before planning any biocide treatment. However, considering the irreversible effects of biocides on the ecological balance in caves, and the low fungal contamination in painted walls of Magura Cave, there is no reason to use conventional biocides in this cave. Further studies, monitoring microbial communities and microclimatic parameters, should be conducted to improve the knowledge on microbial ecology in Magura Cave and possible human impacts, as well as to allow the early detection of potential microbial outbreaks.
KW - Fungi
KW - Rock-art caves
KW - Biocides
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397436
DO - https://doi.org/10.5038/1827-806X.46.1.2061
SN - 0392-6672
VL - 46
IS - 1
SP - 67
EP - 80
PB - Scholar Commons
CY - Tampa, FL, USA
AN - OPUS4-39743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hattrick-Simpers, J.
A1 - Li, K.
A1 - Greenwood, M.
A1 - Black, R.
A1 - Witt, Julia
A1 - Kozdras, M.
A1 - Pang, X.
A1 - Özcan Sandikcioglu, Özlem
T1 - Designing durable, sustainable, high-performance materials for clean energy infrastructure
N2 - Civilization and modern societies would not be possible without manmade materials. Considering their production volumes, their supporting role in nearly all industrial processes, and the impact of their sourcing and production on the environment, metals and alloys are and will be of prominent importance for the clean energy transition. The focus of materials discovery must move to more specialized, application-tailored green alloys that outperform the legacy materials not only in performance but also in sustainability and resource efficiency. This white paper summarizes a joint Canadian-German initiative aimed at developing a materials acceleration platform (MAP) focusing on the discovery of new alloy families that will address this challenge. We call our initiative the “Build to Last Materials Acceleration Platform” (B2L-MAP) and present in this perspective our concept of a three-tiered self-driving laboratory that is composed of a simulation-aided pre-selection module (B2L-select), an artificial intelligence (AI)-driven experimental lead generator (B2L-explore), and an upscaling module for durability assessment (B2L-assess). The resulting tool will be used to identify and subsequently demonstrate novel corrosion-resistant alloys at scale for three key applications of critical importance to an offshore, wind-driven hydrogen plant (reusable electrical contacts, offshore infrastructure, and oxygen evolution reaction catalysts).
KW - Material Acceleration Platforms (MAPs)
KW - Self-driving-labs (SDLs)
KW - Automation
KW - Artificial Intelligence (AI)
KW - Elektrolyse
KW - Structural Materials
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568452
DO - https://doi.org/10.1016/j.xcrp.2022.101200
SN - 2666-3864
VL - 4
IS - 1
SP - 1
EP - 11
PB - Cell Press ; Elsevier
CY - Maryland Heights, MO
AN - OPUS4-56845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bender, R.
A1 - Féron, D.
A1 - Mills, D.
A1 - Ritter, S.
A1 - Bäßler, Ralph
A1 - Bettge, Dirk
A1 - de Graeve, I.
A1 - Dugstad, A.
A1 - Grassini, S.
A1 - Hack, T.
A1 - Halama, M.
A1 - Han, E.-H.
A1 - Harder, T.
A1 - Hinds, G.
A1 - Kittel, J.
A1 - Krieg, R.
A1 - Leygraf, C.
A1 - Martinelli, L.
A1 - Mol, A.
A1 - Neff, D.
A1 - Nilsson, J.-O.
A1 - Odnevall, I.
A1 - Paterson, S.
A1 - Paul, S.
A1 - Prošek, T.
A1 - Raupach, M.
A1 - Revilla, R. I.
A1 - Ropital, F.
A1 - Schweigart, H.
A1 - Szala, E.
A1 - Terryn, H.
A1 - Tidblad, J.
A1 - Virtanen, S.
A1 - Volovitch, P.
A1 - Watkinson, D.
A1 - Wilms, M.
A1 - Winning, G.
A1 - Zheludkevich, M.
T1 - Corrosion challenges towards a sustainable society
N2 - A global transition towards more sustainable, affordable and reliable energy systems is being stimulated by the Paris Agreement and the United Nation's 2030 Agenda for Sustainable Development. This poses a challenge for the corrosion industry, as building climate‐resilient energy systems and infrastructures brings with it a long‐term direction, so as a result the long‐term behaviour of structural materials (mainly metals and alloys) becomes a major prospect. With this in mind “Corrosion Challenges Towards a Sustainable Society” presents a series of cases showing the importance of corrosion protection of metals and alloys in the development of energy production to further understand the science of corrosion, and bring the need for research and the consequences of corrosion into public and political focus. This includes emphasis on the limitation of greenhouse gas emissions, on the lifetime of infrastructures, implants, cultural heritage artefacts, and a variety of other topics.
KW - Corrosion
KW - Corrosion costs
KW - Corrosion protection
KW - Preventive strategies
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554801
DO - https://doi.org/10.1002/maco.202213140
SN - 1521-4176
VL - 73
IS - 11
SP - 1730
EP - 1751
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Noeller, Renate
A1 - Feldmann, Ines
A1 - Kasztovszky, Z.
A1 - Szőkefalvi-Nagy, Z.
A1 - Kovács, I.
T1 - Characteristic Features of Lapis Lazuli from Different Provenances, Revised by µXRF, ESEM, PGAA and PIXE
N2 - The objective of this study is to find out, to what extent the geochemical characteristics of lapis lazuli can be utilized in respect to its provenance. A wide range of variables is taken into consideration depending on the quantity of samples analysed from a specific geological region and the methods applied. In order to provide evidence, a multi-technique analytical approach using µXRF, ESEM, PGAA and PIXE is applied to samples from the most famous deposits of lapis lazuli. Special elements determined as fingerprints are compared in relation to the forming conditions obvious in textural features. The results and statistical output allow a differentiation that enables an optimized local classification of the blue stone. An absolute requirement for all geo-tracing performed on blue colored cultural objects of unknown provenance is awareness of the limits of analysis. The possible sources of lapis lazuli are tested by analysing the blue pigment used as paint on murals and ink on manuscripts from the Silk Road.
KW - Provenance studies
KW - Micro-XRF
KW - Lapis lazuli
KW - ESEM
KW - PGAA
KW - PIXE
KW - Pigment analyses
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480048
DO - https://doi.org/10.17265/2328-2193/2019.02.003
VL - 7
IS - 2
SP - 57
EP - 69
PB - David Publishing
AN - OPUS4-48004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, Juan-Carlos
A1 - Facchini, Leonardo
A1 - Wilbig, Janka
A1 - Zocca, Andrea
A1 - Stoll, Enrico
A1 - Günster, Jens
T1 - Melt Pool Stability during Local Laser Melting of Lunar Regolith with Large Laser Spots and Varying Gravity
N2 - In order to increase the sustainability of future lunar missions, techniques for in-situ resource utilization (ISRU) must be developed. In this context, the local melting of lunar dust (regolith) by laser radiation for the production of parts and larger structures was investigated in detail. With different experimental setups in normal and microgravity, laser spots with diameters from 5 mm to 100 mm were realized to melt the regolith simulant EAC-1A and an 80%/20% mixture of TUBS-T and TUBS-M, which are used as a substitute for the actual lunar soil. In the experiments performed, the critical parameters are the size of the laser spot, the velocity of the laser spot on the surface of the powder bed, the gravity and the wettability of the powder bed by the melt. The stability of the melt pool as a function of these parameters was investigated and it was found that the formation of a stable melt pool is determined by gravity for large melt pool sizes in the range of 50 mm and by surface tension for small melt pool sizes in the range of a few mm.
KW - Additive Manufacturing
KW - Regolith
KW - Laser melting
KW - ISRU
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639621
DO - https://doi.org/10.1016/j.amf.2025.200227
SN - 2950-4317
VL - 4
IS - 3
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-63962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diener, S.
A1 - Zocca, Andrea
A1 - Günster, Jens
T1 - Literature review: Methods for achieving high powder bed densities in ceramic powder bed based additive manufacturing
N2 - In additive manufacturing the powder bed based processes binder jetting and powder bed fusion are increasingly used also for the production of ceramics. Final part properties depend to a high percentage on the powder bed density. Therefore, the aim is to use the best combination of powder deposition method and powder which leads to a high packing of the particles. The influence of flowability, powder properties and deposition process on the powder bed density is discussed and the different deposition processes including slurry-based ones are reviewed.
It turns out that powder bed density reached by slurry-based layer deposition exceeds conventional powder deposition, however, layer drying and depowdering are extra steps or more time-consuming for the slurry route.
Depending on the material properties needed the most suitable process for the part has to be selected.
KW - Additive Manufacturing
KW - Powder-based processes
KW - Powder bed density
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534992
DO - https://doi.org/10.1016/j.oceram.2021.100191
VL - 8
SP - 100191
PB - Elsevier Ltd.
AN - OPUS4-53499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breitenbach, Romy
A1 - Gerrits, Ruben
A1 - Dementyeva, Polina
A1 - Knabe, Nicole
A1 - Schumacher, Julia
A1 - Feldmann, Ines
A1 - Radnik, Jörg
A1 - Ryo, M.
A1 - Gorbushina, Anna
T1 - The role of extracellular polymeric substances of fungal biofilms in mineral attachment and weathering
N2 - The roles extracellular polymeric substances (EPS) play in mineral attachment and weathering were studied using genetically modified biofilms of the rock-inhabiting fungus Knufia petricola strain A95. Mutants deficient in melanin and/or carotenoid synthesis were grown as air-exposed biofilms. Extracted EPS were quantified and characterised using a combination of analytical techniques. The absence of melanin affected the quantity and composition of the produced EPS: mutants no longer able to form melanin synthesised more EPS containing fewer pullulan-related glycosidic linkages. Moreover, the melanin-producing strains attached more strongly to the mineral olivine and dissolved it at a higher rate. We hypothesise that the pullulan-related linkages, with their known adhesion functionality, enable fungal attachment and weathering. The released phenolic intermediates of melanin synthesis in the Δsdh1 mutant might play a role similar to Fe-chelating siderophores, driving olivine dissolution even further. These data demonstrate the need for careful compositional and quantitative analyses of biofilm-created microenvironments.
KW - Biofilms
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549025
DO - https://doi.org/10.1038/s41529-022-00253-1
SN - 2397-2106
VL - 6
SP - 1
EP - 11
PB - Springer Nature
CY - London
AN - OPUS4-54902
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michna, A.
A1 - Maciejewska-Prończuk, J.
A1 - Wasilewska, M.
A1 - Kilicer, Tayfun
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
T1 - Effect of the Anchoring Layer and Transport Type on the Adsorption Kinetics of Lambda Carrageenan
N2 - The kinetics of lambda carrageenan (λ-car) adsorption/desorption on/from anchoring layers under diffusion- and convection-controlled transport conditions were investigated. The eighth generation of poly(amidoamine) dendrimers and branched polyethyleneimine possessing different shapes and polydispersity indexes were used for anchoring layer formation. Dynamic light scattering, electrophoresis, streaming potential measurements, optical waveguide lightmode spectroscopy, and quartz crystal microbalance were applied to characterize the formation of mono- and bilayers. The unique combination of the employed techniques enabled detailed insights into the mechanism of the λ-car adsorption mainly controlled by electrostatic interactions. The results show that the macroion adsorption efficiency is strictly correlated with the value of the final zeta potentials of the anchoring layers, the transport type, and the initial bulk concentration of the macroions. The type of the macroion forming the anchoring layer had a minor impact on the kinetics of λ-car adsorption. Besides significance to basic science, the results presented in this paper can be used for the development of biocompatible and stable macroion multilayers of well-defined electrokinetic properties and structure.
KW - AFM
KW - Dynamic light scattering
KW - Electrophoresis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540546
DO - https://doi.org/10.1021/acs.jpcb.1c03550
VL - 125
IS - 28
SP - 7797
EP - 7808
PB - American Chemical Society
AN - OPUS4-54054
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cestari, F.
A1 - Yang, Y.
A1 - Wilbig, Janka
A1 - Günster, Jens
A1 - Motta, A.
A1 - Sglavo, V.
T1 - Powder 3D printing of bone scaffolds with uniform and gradient pore sizes using cuttlebone-derived calcium phosphate and glass-ceramic
N2 - The pore geometry of bone scaffolds has a major impact on their cellular response; for this reason, 3D printing is an attractive technology for bone tissue engineering, as it allows for the full control and design of the porosity. Calcium phosphate materials synthesized from natural sources have recently attracted a certain interest because of their similarity to natural bone, and they were found to show better bioactivity than synthetic compounds. Nevertheless, these materials are very challenging to be processed by 3D printing due to technological issues related to their nanometric size. In this work, bone scaffolds with different pore geometries, with a uniform size or with a size gradient, were fabricated by binder jetting 3D printing using a biphasic calcium phosphate (BCP) nanopowder derived from cuttlebones. To do so, the nanopowder was mixed with a glass-ceramic powder with a larger particle size (45–100 µm) in 1:10 weight proportions. Pure AP40mod scaffolds were also printed. The sintered scaffolds were shown to be composed mainly by hydroxyapatite (HA) and wollastonite, with the amount of HA being larger when the nanopowder was added because BCP transforms into HA during sintering at 1150 ◦C. The addition of bio-derived powder increases the porosity from 60% to 70%, with this indicating that the nanoparticles slow down the glass-ceramic densification. Human mesenchymal stem cells were seeded on the scaffolds to test the bioactivity in vitro. The cells’ number and metabolic activity were analyzed after 3, 5 and 10 days of culturing.
The cellular behavior was found to be very similar for samples with different pore geometries and compositions. However, while the cell number was constantly increasing, the metabolic activity on the scaffolds with gradient pores and cuttlebone-derived powder decreased over time, which might be a sign of cell differentiation. Generally, all scaffolds promoted fast cell adhesion and proliferation, which were found to penetrate and colonize the 3D porous structure.
KW - Bioactivity
KW - Cuttlefish
KW - Biphasic calcium phosphate
KW - Binder jetting
KW - Scaffold geometry
KW - Hausner ratio
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553627
DO - https://doi.org/10.3390/ma15155139
SN - 1996-1944
VL - 15
IS - 15
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-55362
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Chayanika
A1 - Kastania, Eleni
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
T1 - Corrosion protection properties of poly(4-vinyl pyridine) containing multilayer polymeric coatings on magnesium alloy AZ31
N2 - The aim of this study is to develop polymeric thin films for corrosion protection of magnesium alloy AZ31. As polymer matrix, poly(4-vinyl pyridine) (P4VP) is selected due to its semiconducting properties and protonic conductivity. Polyacrylic acid is tested as crosslinking layers to improve interfacial adhesion. The macroscopic corrosion properties of the multilayer coatings are investigated by means of electrochemical methods, such as linear sweep voltammetry and electrochemical impedance spectroscopy (EIS), in corrosive media simulating technical and biomedical applications. It is demonstrated that thin multilayer coatings can suppress the corrosion rates of magnesium alloys. To our best knowledge, this is the first demonstration of the use of P4VP as a conducting polymer film with protonic conductivity for corrosion protection of magnesium alloys.
KW - Multilayercoatings
KW - AZ31
KW - Corrosion protection
KW - Intrinsically conducting polymers
KW - Magnesium alloys
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551799
DO - https://doi.org/10.1002/maco.202112708
SN - 0947-5117
VL - 73
IS - 3
SP - 427
EP - 435
PB - Wiley VHC-Verlag
AN - OPUS4-55179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chi, J.
A1 - Agea Blanco, B.
A1 - Bruno, Giovanni
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Self-Organization Postprocess for Additive Manufacturingin Producing Advanced Functional Structure and Material
N2 - Additive manufacturing (AM) is developing rapidly due to itsflexibility in producing complex geometries and tailored material compositions. However, AM processes are characterized by intrinsic limitations concerning their resolution and surface finish, which are related to the layer-by-layer stacking process. Herein, a self-organization process is promoted as an approach to improve surface quality and achieve optimization of 3D minimal surface lightweight structures. The self-organization is activated after the powder bed 3D printing process via local melting, thereby allowing surface tension-driven viscous flow.The surface roughness Ra (arithmetic average of the roughness profile) could bedecreased by a factor of 1000 and transparent lenses and complex gyroid structures could be produced for demonstration. The concept of self-organization is further elaborated by incorporating external magnetic fields to intentionally manipulate magnetic particles, which are mixed with the polymer before printing and self-organization. This concept can be applied to develop programmable materials with specific microtextures responding to the external physical conditions.
KW - Additive Manufacturing
KW - Self-organization
KW - Triply Periodical Minimal Surface
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540588
DO - https://doi.org/10.1002/adem.202101262
VL - 24
IS - 6
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-54058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stinville, J.C.
A1 - Charpagne, M.A.
A1 - Maaß, Robert
A1 - Proudhon, H.
A1 - Ludwig, W.
A1 - Callahan, P.G.
A1 - Wang, F.
A1 - Beyerlein, I.J.
A1 - Echlin, M.P.
A1 - Pollock, T.M.
T1 - Insights into Plastic Localization by Crystallographic Slip from Emerging Experimental and Numerical Approaches
N2 - Advanced experimental and numerical approaches are being developed to
capture the localization of plasticity at the nanometer scale as a function of the multiscale and heterogeneous microstructure present in metallic materials.
These innovative approaches promise new avenues to understand microstructural effects on mechanical properties, accelerate alloy design, and enable more accurate mechanical property prediction. This article provides an overview of emerging approaches with a focus on the localization of plasticity by crystallographic slip. New insights into the mechanisms and mechanics of strain localization are addressed. The consequences of the localization of plasticity by deformation slip for mechanical properties of metallic materials are also detailed.
KW - Slip localization
KW - Metallic materials
KW - Experimental and numerical techniques
KW - Mechanical properties
KW - Plasticity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578398
DO - https://doi.org/10.1146/annurev-matsci-080921-102621
SN - 1531-7331
VL - 53
SP - 275
EP - 317
AN - OPUS4-57839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mendive-Tapia, E.
A1 - Neugebauer, J.
A1 - Hickel, Tilmann
T1 - Ab initio calculation of the magnetic Gibbs free energy of materials using magnetically constrained supercells
N2 - We present a first-principles approach for the computation of the magnetic Gibbs free energy ofmaterials using magnetically constrained supercell calculations. Our approach is based on an adiabatic approximation of slowly varying local moment orientations, the so-called finite-temperature disordered local moment picture. It describes magnetic phase transitions and how electronic and/or magnetostructural mechanisms generate a discontinuous (first-order) character. We demonstrate that the statistical mechanics of the local moment orientations can be described by an affordable number of supercell calculations containing noncollinear magnetic configurations.
The applicability of our approach is illustrated by firstly studying the ferromagnetic state in bcc Fe. We then investigate the temperature-dependent properties of a triangular antiferromagnetic state stabilizing in two antiperovskite systems Mn3AN (A = Ga, Ni). Our calculations provide the negative thermal expansion of These materials as well as the ab initio origin of the discontinuous character of the phase transitions, electronic and/or magnetostructural, in good agreement with experiment.
KW - Ab initio
KW - Thermodynamics
KW - Magnetic alloys
KW - Phase transformations
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543710
DO - https://doi.org/10.1103/PhysRevB.105.064425
SN - 2469-9969
VL - 105
IS - 6
SP - 1
EP - 6
PB - American Institute of Physics
CY - Woodbury, NY
AN - OPUS4-54371
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sözen, H.I.
A1 - Ener, S.
A1 - Maccari, F.
A1 - Fayyazi, B.
A1 - Gutfleisch, O.
A1 - Neugebauer, J.
A1 - Hickel, Tilmann
T1 - Combined ab initio and experimental screening of phase stabilities in the Ce-Fe-Ti-X system (X = 3d and 4d metals)
N2 - One of the main challenges for the synthesis and application of the promising hard-magnetic compound CeFe11Ti is the formation of Laves phases that are detrimental for their thermodynamic stability and magnetic properties. In this paper, we present an ab initio based approach to modify the stability of these phases in the Ce-Fe-Ti system by additions of 3d and 4d elements. We combine highly accurate free-energy calculations with an efficient screening technique to determine the critical annealing temperature for the formation of Ce(Fe,X)11Ti. The central findings are the dominant role of the formation enthalpy at T = 0 K on chemical trends and the major relevance of partial chemical decompositions. Based on these insights, promising transition metals to promote the stability of the hard-magnetic phase, such as Zn and Tc, were predicted. The comparison with suction casting and reactive crucible melting experiments for Ce-Fe-Ti-X (X = Cu, Ga, Co, and Cr) highlights the relevance of additional phases and quaternary elements.
KW - Density functional theory
KW - Phase stability
KW - Energy materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568850
DO - https://doi.org/10.1103/PhysRevMaterials.7.014410
SN - 2475-9953
VL - 7
SP - 1
EP - 15
AN - OPUS4-56885
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Ni, H.C.
A1 - Chakraborty, A.
A1 - Ghassemi-Armaki, H.
A1 - Zuo, J.M.
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - Segregation-induced grain-boundary precipitation during early stages of liquid-metal embrittlement of an advanced high-strength steel
N2 - Liquid-metal embrittlement (LME) of galvanized (Zn-coated) advanced high-strength steels is a long-known problem in materials science. Here we reveal the initial microstructural processes underneath the Zn-coating that lead to LME-microcrack initiation in the steel substrate. We track the microstructural evolution during the first tens of milliseconds and find pronounced signatures of Fe-Zn intermetallic precipitation in both ferrite grain boundaries and at internal ferrite-oxide phase boundaries. In concert with novel CALPHAD-integrated density-based thermodynamic modelling, we demonstrate that Zn-rich intermetallic phase-nucleation can occur at markedly low processing temperatures due to a segregation transition. We show that a small Znenrichment caused by Zn bulk-diffusion during the initial temperature rise in a joining process is sufficient to induce the segregation transition and subsequent nucleation of Fe-Zn intermetallic grain-boundary phases, which the experiments link to crack initiation sites. These findings direct focus onto LME-controlling microstructural and thermodynamic phenomena at temperatures below the ductility trough and the austenite formation temperature.
KW - Resistance spot welding
KW - Liquid-metal embrittlement
KW - Steels
KW - Grain boundaries
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581067
DO - https://doi.org/10.1016/j.actamat.2023.119243
VL - 259
SP - 1
EP - 12
PB - Elsevier Ltd
AN - OPUS4-58106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rizzardi, Q.
A1 - McElfresh, C.
A1 - Sparks, G.
A1 - Stauffer, D.
A1 - Marian, J.
A1 - Maaß, Robert
T1 - Mild-to-wild plastic transition is governed by athermal screw dislocation slip in bcc Nb
N2 - Plastic deformation in crystals is mediated by the motion of line defects known as dislocations.
For decades, dislocation activity has been treated as a homogeneous, smooth continuous process. However, it is now recognized that plasticity can be determined by longrange correlated and intermittent collective dislocation processes, known as avalanches. Here we demonstrate in body-centered cubic Nb how the long-range and scale-free dynamics at room temperature are progressively quenched out with decreasing temperature, eventually revealing intermittency with a characteristic length scale that approaches the Burgers Vector itself. Plasticity is shown to be bimodal across the studied temperature regime, with conventional thermally-activated smooth plastic flow (‘mild’) coexisting with sporadic Bursts (‘wild’) controlled by athermal screw dislocation activity, thereby violating the classical Notion of temperature-dependent screw dislocation motion at low temperatures. An abrupt increase of the athermal avalanche component is identified at the critical temperature of the material.
Our results indicate that plasticity at any scale can be understood in terms of the coexistence of these mild and wild modes of deformation, which could help design better alloys by suppressing one of the two modes in desired temperature Windows.
KW - Plastic deformation
KW - Microplastic stress
KW - Intermittent microplasticity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543927
DO - https://doi.org/10.1038/s41467-022-28477-4
VL - 13
IS - 1
SP - 1
EP - 9
PB - Nature
AN - OPUS4-54392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhao, H.
A1 - Chakraborty, Poulami
A1 - Ponge, D.
A1 - Hickel, Tilmann
A1 - Sun, B.
A1 - Wu, C.-H.
A1 - Gault, B.
A1 - Raabe, D.
T1 - Hydrogen trapping and embrittlement in high-strength Al alloys
N2 - Ever more stringent regulations on greenhouse gas emissions from transportation motivate efforts to revisit materials used for vehicles. High-strength aluminium alloys often used in aircrafts could help reduce the weight of automobiles, but are susceptible to environmental degradation. Hydrogen ‘embrittlement’ is often indicated as the main culprit; however, the exact mechanisms underpinning failure are not precisely known: atomic-scale analysis of H inside an alloy remains a challenge, and this prevents deploying alloy design strategies to enhance the durability of the materials. Here we performed near-atomic-scale analysis of H trapped in second-phase particles and at grain boundaries in a high-strength 7xxx Al alloy. We used these observations to guide atomistic ab initio calculations, which show that the co-segregation of alloying elements and H favours grain boundary decohesion, and the strong partitioning of H into the second-phase particles removes solute H from the matrix, hence preventing H embrittlement. Our insights further advance the mechanistic understanding of H-assisted embrittlement in Al alloys, emphasizing the role of H traps in minimizing cracking and guiding new alloy design.
KW - Atomistic models
KW - Hydrogen
KW - Metals and alloys
KW - Mechanical properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543631
DO - https://doi.org/10.1038/s41586-021-04343-z
SN - 1476-4687
VL - 602
IS - 7897
SP - 437
EP - 441
PB - Nature Publ. Group
CY - London
AN - OPUS4-54363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sözen, H.I.
A1 - Mendive-Tapia, E.
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
T1 - Ab initio investigations of point and complex defect structures in B2-FeAl
N2 - We study single-site and two-site defect structures in B2-type Fe-Al alloys by means of density functional theory supercell calculations. The defect formation energies are calculated as functions of the chemical potential, which are used to obtain the dependence of the defect concentrations on Al content at different temperatures. We also examine the converging behavior of the formation energies with respect to the supercell size to study the corresponding limit of dilute defects. The effect of magnetism is investigated by considering nonmagnetic, ferromagnetic, and paramagnetic states, calculations for the latter showing that the magnitude of the local magnetic moments strongly impacts the defect formation energies. The methodological studies are used to provide explanations for the wide spread of defect formation energies reported by experiments and other theoretical investigations. Based on these insights, the stability of the B2-FeAl structure as a function of Al concentration is obtained and discussed.
KW - Atomistic models
KW - Defects
KW - Thermodynamics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546956
DO - https://doi.org/10.1103/PhysRevMaterials.6.023603
SN - 2475-9953
VL - 6
IS - 2
SP - 1
EP - 11
PB - APS
CY - College Park, MD
AN - OPUS4-54695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tielemann, Christopher
A1 - Reinsch, Stefan
A1 - Maaß, Robert
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal nucleation tendency and crystal surface energy obtained from bond energies and crystal lattice data
N2 - We present an easy-to-apply method to predict structural trends in the internal nucleation tendency of oxide glasses. The approach is based on calculated crystal fracture surface energies derived from easily accessible diatomic bond energy and crystal lattice data. The applicability of the method is demonstrated on literature nucleation data for isochemically crystallizing oxide glasses.
KW - Glass
KW - Nucleation tendency
KW - Fracture surface energy
KW - Crystal lattice
KW - Bond energy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548814
DO - https://doi.org/10.1016/j.nocx.2022.100093
SN - 2590-1591
VL - 14
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-54881
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holzer, Marco
A1 - Johansen, Sidsel M.
A1 - Christensen, Johan F.S.
A1 - Smedskjaer, Morten M.
A1 - Cicconi, Maria Rita
A1 - de Ligny, Dominique
A1 - Müller, Ralf
A1 - de Camargo, Andrea S.S.
A1 - Maaß, Robert
T1 - Direct connection between secondary relaxation mode and fracture toughness in alkali-aluminosilicate glasses
N2 - Oxide glasses are intrinsically brittle, lacking sufficient atomic-scale mechanisms that can relax mechanical stresses in the vicinity of a propagating crack. As a result, fracture is typically well-captured by considering local bond rupture at the crack tip. Here we demonstrate that barrier energies related to the low-temperature 𝛾-relaxation mode in alkali-aluminosilicate glasses are inversely related to the fracture toughness measured via standardized three-point bending fracture experiments. This holds true for both a series with varying cations (Li, Na, K) and one with varying Li concentration. The structural rationale for this finding is gained via Raman spectroscopy. The findings suggest that a fundamental structural relaxation mode measured on bulk specimens can serve as an effective guideline for fracture toughness of oxide glasses. Data for additional silicate glasses support this conclusion.
KW - Fracture toughness
KW - Oxide glass
KW - Mechanical properties
KW - Alkali-aluminosilicate glasses
KW - Internal friction
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651540
DO - https://doi.org/10.1016/j.mtadv.2025.100669
SN - 2590-0498
VL - 29
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-65154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moschetti, Michael
A1 - Lemiasheuski, Anton
A1 - Bajer, Evgenia
A1 - Porohovoj, Ilja
A1 - Göbel, Artur
A1 - Pfennig, Anja
A1 - Bettge, Dirk
A1 - Maaß, Robert
T1 - Robot-Assisted Automated Serial-Sectioning and Imaging for 3D Microstructural Investigations
N2 - Comprehensive materials characterization requires precise structural knowledge beyond traditional methods. The robot-assisted automated serial-sectioning and imaging (RASI) platform, developed at BAM, provides automated 3D metallographic reconstructions, enabling detailed microstructural analysis of technical materials. This article showcases RASI’s capabilities through several case studies, including characterization of lamellar graphite in gray cast iron, porosity in sintered steel, melt pool morphology in additively manufactured 316L stainless steel, defects in metal-ceramic packages, and oxidation behavior in an Fe-12Cr-2Co alloy. By automating sample handling, mechanical serial-sectioning, etching, and optical imaging, RASI captures complex 3D microstructures with high precision and at high speed. This approach reveals microstructural features missed by 2D analysis, even using stereological assumptions. Specifically, statistically rare and large microstructural features, such as secondary phases or interconnected pores, become apparent, which 2D methods cannot reveal. The generated volumetric data can furthermore serve as quantitative reference datasets (i.e., the ‘ground truth’) essential for validating other 3D characterization techniques and computational models, helping to bridge the gap between predictive simulations and real-world material behavior. RASI’s modular design makes it a flexible tool that provides realistic 3D insights into materials, which can be used for advanced materials research, process optimization, and quality control.
KW - 3D metallography
KW - Automated microstructure characterization
KW - Image segmentation
KW - Mechanical polishing based serial-sectioning
KW - Process-microstructure-property relationships
KW - Quantitative microstructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649614
DO - https://doi.org/10.1002/adem.202502202
SN - 1527-2648
VL - 28
IS - 2
SP - 1
EP - 14
PB - Wiley-VCH GmbH
AN - OPUS4-64961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tehranchi, Ali
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
T1 - Hydrogen enhanced dislocation cross-slip in polycrystalline nickel
N2 - Hydrogen embrittlement (HE), degradation of the mechanical properties of metals due to the presence of hydrogen, is a persistent problem that has been attracting the attention of the material science community for about fifteen decades. Extensive experimental observations indicate the presence of nanovoids and the increase of free volume at the grain boundaries in hydrogen contaminated metals. This rate-dependent phenomenon motivates theoretical investigations of the underlying mechanisms. Here, a hydrogen enhanced cross-slip (HECS) mechanism in the close vicinity of the grain boundaries is demonstrated by direct molecular dynamics simulations and theoretical calculations. To this end, the interaction of screw dislocations with a variety of symmetric tilt grain boundaries in H-charged and H-free bicrystalline nickel is examined. The presence of segregated H atoms at the grain boundaries induces a stress field in their vicinity, and thus,- the barrier for cross-slip of screw dislocations considerably decreases. The enhanced cross-slip of dislocations facilitates the formation of jogs on bowedout dislocations. These jogs can form vacancies during the glide process. This mechanism of defect production shows nanoscale evidence of enhanced vacancy formation and subsequent increase in the free volume along the grain boundaries in the presence of H.
KW - Hydrogen embrittlement
KW - Dislocation
KW - Grain boundary
KW - Void formation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649858
DO - https://doi.org/10.1103/7l8f-3fbm
SN - 2475-9953
VL - 9
IS - 12
SP - 1
EP - 16
PB - American Physical Society (APS)
AN - OPUS4-64985
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Wallis, Theophilus
A1 - Maaß, Robert
A1 - Darvishi Kamachali, Reza
T1 - Thermodynamics of grain boundary segregation transition and their relevance for liquid metal embrittlement in Fe-Zn system
N2 - Grain boundaries (GBs) are common sites of failure in polycrystalline materials. Recently, a massive Zn segregation transition at Fe GBs was discovered and shown to act as a potent precursor of liquid metal embrittlement (LME) in the Fe-Zn system (Kamachali et al., Scripta Materialia 238 (2024) 115758). In this study, we elaborate on how temperature, GB type and the chemo-structurally coupled phase decomposition at the GB impact this segregation transition. CALPHAD and atomistic simulation data were utilized as inputs to conduct quantitative density-based thermodynamic modeling and phase-field simulations across various GBs, alloy compositions, and temperatures. We reveal that once the segregation transition becomes possible, the GB structural variation stabilizes spinodally formed Zn-rich phases within the GB region, with a higher tendency in disordered GBs. GB phase diagrams were constructed to identify and analyze the range of critical temperatures and alloy compositions associated with the segregation transition. The phase diagrams reveal that the miscibility gap for more disordered GB expands and, although the segregation transition is inevitable and occurs for all GBs, the barrier to triggering it is lower for more disordered GBs. Based on our thermodynamic analyses, potential processing modifications and GB engineering strategies for mitigating segregation-induced LME are thoroughly discussed.
KW - Thermodynamics
KW - Phase-Field Modelling
KW - Steels
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634145
DO - https://doi.org/10.1016/j.actamat.2025.121134
SN - 1359-6454
VL - 296
SP - 1
EP - 11
PB - Elsevier BV
AN - OPUS4-63414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Esakkiraja, N.
A1 - Vishwakarma, A.
A1 - Makineni, S. K.
A1 - Jayaram, V.
A1 - Hickel, Tilmann
A1 - Divinski, S. V.
A1 - Paul, A.
T1 - Diffusion-controlled growth and microstructural evolution between Pt and Pd containing B2-NiAl bondcoats and Ni-based single crystal superalloy
N2 - Pt-modified NiAl bond coats are used to extend the lifetime of blades in gas turbine engine applications. However, they suffer from the growth of deleterious precipitates within the interdiffusion zone. Partial substitution of Pt by Pd is advantageous in reducing the interdiffusion zone thickness between the bond coat and the superalloy, providing comparable oxidation properties, and critically reducing the propensity to form brittle (Pt,Ni)Al2 precipitates. In this study, we utilize the pseudo-binary diffusion couple method to estimate the interdiffusion coefficients of Ni and Al in Pd, Pd-Pt and Pt-modified nickel aluminides. Additionally, the main and cross-interdiffusion coefficients are estimated in the ternary diffusion couples. The estimated diffusion coefficients in the 𝛽-NiAl phase reflect on the thickness of the 𝛽 phase in the superalloy bond coat interdiffusion zone. Pd reduces the pseudo-binary interdiffusion coefficients of Ni–Al and also decreases the main and cross-ternary interdiffusion coefficients. This correlates with the reduction of the interdiffusion zone thickness by Pd. The diffusion process is strongly assisted by point defects in this phase. Ab initio-informed defect calculations are done to explain diffusion retardation in the presence of Pd (compared to Pt) with decreased defect concentrations. Furthermore, through in-depth microstructure characterization performed by electron probe micro analyser, transmission electron microscopy, and atom probe tomography, the presence of 𝜎, 𝑅 and 𝜇 phases as TCP precipitates in the interdiffusion zone are identified. The results give insights into the coatings’ diffusional properties that influence the service life of the product.
KW - Interdiffusion
KW - Bondcoat
KW - Topologically close pack (TCP) phase
KW - Transmission electron microscopy
KW - Atom probe tomography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618091
DO - https://doi.org/10.1016/j.actamat.2024.119687
SN - 1359-6454
VL - 266
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61809
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bekemeier, Simon
A1 - Caldeira Rêgo, C. R.
A1 - Mai, H. L.
A1 - Sikia, Ujjal
A1 - Waseda, O.
A1 - Apel, M.
A1 - Arendt, F.
A1 - Aschemann, A.
A1 - Bayerlein, Bernd
A1 - Courant, R.
A1 - Dziwis, G.
A1 - Fuchs, F.
A1 - Giese, U.
A1 - Junghanns, K.
A1 - Kamal, M.
A1 - Koschmieder, L.
A1 - Leineweber, S.
A1 - Luger, M.
A1 - Lukas, M.
A1 - Maas, J.
A1 - Mertens, J.
A1 - Mieller, Björn
A1 - Overmeyer, L.
A1 - Pirch, N.
A1 - Reimann, J.
A1 - Schröck, S.
A1 - Schulze, P.
A1 - Schuster, J.
A1 - Seidel, A.
A1 - Shchyglo, O.
A1 - Sierka, M.
A1 - Silze, F.
A1 - Stier, S.
A1 - Tegeler, M.
A1 - Unger, Jörg F.
A1 - Weber, M.
A1 - Hickel, Tilmann
A1 - Schaarschmidt, J.
T1 - Advancing Digital Transformation in Material Science: The Role of Workflows Within the MaterialDigital Initiative
N2 - The MaterialDigital initiative represents a major driver toward the digitalization of material science. Next to providing a prototypical infrastructure required for building a shared data space and working on semantic interoperability of data, a core focus area of the Platform MaterialDigital (PMD) is the utilization of workflows to encapsulate data processing and simulation steps in accordance with findable, accessible, interoperable, and reusable principles. In collaboration with the funded projects of the initiative, the workflow working group strives to establish shared standards, enhancing the interoperability and reusability of scientific data processing steps. Central to this effort is the Workflow Store, a pivotal tool for disseminating workflows with the community, facilitating the exchange and replication of scientific methodologies. This article discusses the inherent challenges of adapting workflow concepts, providing the perspective on developing and using workflows in the respective domain of the various funded projects. Additionally, it introduces the Workflow Store’s role within the initiative and outlines a future roadmap for the PMD workflow group, aiming to further refine and expand the role of scientific workflows as a means to advance digital transformation and foster collaborative research within material science.
KW - Digitalisation
KW - FAIR principles
KW - MaterialDigital
KW - Scientific workflows
KW - Semantic interoperability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624088
DO - https://doi.org/10.1002/adem.202402149
SN - 1527-2648
IS - 2402149
SP - 1
EP - 25
PB - Wiley-VCH GmbH
AN - OPUS4-62408
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhu, L.
A1 - Srinivasan, P.
A1 - Gong, Y.
A1 - Hickel, Tilmann
A1 - Grabowski, B.
A1 - Körmann, Fritz
A1 - Neugebauer, J.
T1 - Melting properties of the refractory metals V and W and the binary VW alloy fully from first principles
N2 - We investigate the melting properties of the bcc refractory metals V and W, and the disordered equiatomic VW alloy from first principles. We show that thermal vibrations have a large impact on the electronic density of states (DOS) and thus considerably affect the electronic contribution to the free energy. For W, the impact of vibrations on the electronic free energy of solid and liquid is different. This difference substantially impacts the computed melting point and also triggers a large electronic heat capacity difference between solid and liquid. For V, although vibrations likewise affect the electronic free energy, the effect on the melting properties cancels out to a large degree. For the binary VW alloy we observe a similar impact as for W, but slightly weaker. The underlying physics is explained in terms of the electronic DOS of the solid and liquid phases. Based on our accurate first-principles results, we reveal critical limitations of the Sommerfeld approximation in predicting the electronic heat
KW - Crystal melting
KW - Thermodynamics
KW - Metals
KW - Ab initio molecular dynamics
KW - Density functional theory
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618100
DO - https://doi.org/10.1103/PhysRevB.109.094110
SN - 2469-9950
VL - 109
IS - 9
SP - 1
EP - 18
PB - American Physical Society (APS)
AN - OPUS4-61810
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janssen, J.
A1 - Makarov, E.
A1 - Hickel, Tilmann
A1 - Shapeev, A.V.
A1 - Neugebauer, J.
T1 - Automated optimization and uncertainty quantification of convergence parameters in plane wave density functional theory calculations
N2 - First principles approaches have revolutionized our ability in using computers to predict, explore, and design materials. A major advantage commonly associated with these approaches is that they are fully parameter-free. However, numerically solving the underlying equations requires to choose a set of convergence parameters. With the advent of high-throughput calculations, it becomes exceedingly important to achieve a truly parameter-free approach. Utilizing uncertainty quantification (UQ) and linear decomposition we derive a numerically highly efficient representation of the statistical and systematic error in the multidimensional space of the convergence parameters for plane wave density functional theory (DFT) calculations. Based on this formalism we implement a fully automated approach that requires as input the target precision rather than convergence parameters. The performance and robustness of the approach are shown by applying it to a large set of elements crystallizing in a cubic fcc lattice.
KW - Ab initio simulations
KW - High throughput
KW - convergence parameter
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618632
DO - https://doi.org/10.1038/s41524-024-01388-2
VL - 10
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Yu
A1 - Bo, Zhen-Xing
A1 - Zhou, Hong Bo
A1 - Sun, Bao-An
A1 - Sun, Yong Hao
A1 - Maaß, Robert
A1 - Wang, Wei Hua
T1 - Nanoindentation reveals universal scaling of pop-in plasticity in metallic glasses
N2 - Plastic flow of metallic glasses proceeds intermittently in the inhomogeneous deformation regime. Mediated via shear bands, quasi-static straining gives rise to plastic instabilities that are measured as abrupt displacement bursts or pop-ins. The latter is a well-known feature in nanoindentation, where its first occurrence probes the critical and site-specific stress of nano-scale incipient shear deformation. Here we show that the statistical distribution of the stress and magnitude of the first shear instability, as well as its successive higher-order events, universally follow Weibull statistics across ten different metallic glasses. This indicates a fundamentally identical plastic process across glass-forming alloys and progressing deformation that is governed by a weakest-link phenomenon. This finding stands in strong contrast to crystalline alloys, where both defect nucleation and defect-structure evolution control shear instabilities and depend on the deformation history.
KW - Metallic glasses
KW - Nanoindentation
KW - Intermittent flow
KW - Pop-ins
KW - Weibull distribution
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624772
DO - https://doi.org/10.1016/j.scriptamat.2025.116549
VL - 259
SP - 1
EP - 5
PB - Elsevier Inc.
AN - OPUS4-62477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Mathews, P.
A1 - Berkels, B.
A1 - Delis, W.
A1 - Saood, S.
A1 - Alhassan, A.
A1 - Keuter, P.
A1 - Schneider, J.
A1 - Korte-Kerzel, S.
A1 - Sandlöbes, S.
A1 - Raabe, D.
A1 - Neugebauer, j.
A1 - Dehm, G.
A1 - Hickel, Tilmann
A1 - Scheu, C.
A1 - Zhang, S.
T1 - Materials Design by Constructing Phase Diagrams for Defects
N2 - Phase transformations and crystallographic defects are two essential tools todrive innovations in materials. Bulk materials design via tuning chemicalcompositions is systematized using phase diagrams. It is shown here that thesame thermodynamic concept can be applied to manipulate the chemistry atdefects. Grain boundaries in Mg–Ga system are chosen as a model system,because Ga segregates to the boundaries, while simultaneously improving thestrength and ductility of Mg alloys. To reveal the role of grain boundaries,correlated atomic-scale characterization and simulation to scope and buildphase diagrams for defects are presented. The discovery is enabled bytriggering phase transformations of individual grain boundaries through localalloying, and sequentially imaging the structural and chemical changes usingatomic-resolution scanning transmission electron microscopy. Ab initiosimulations determined the thermodynamic stability of grain boundaryphases, and found out that increasing Ga content enhances grain boundarycohesion, relating to improved ductility. The methodology to trigger, trace,and simulate defect transformation at atomic resolution enables a systematicdevelopment of defect phase diagrams, providing a valuable tool to utilizechemical complexity and phase transformations at defects.
KW - Automatic pattern recognition
KW - Defect phase diagram
KW - Density functional theory
KW - Grain boundary complexion
KW - Transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618063
DO - https://doi.org/10.1002/adma.202402191
SN - 1521-4095
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-61806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Das, Amlan
A1 - Rashidi, Reza
A1 - Dufresne, Eric
A1 - Maaß, Robert
T1 - Metallic glasses: Elastically stiff yet flowing at any stress
N2 - Crystalline solids have a minimum stress needed to displace atoms or to move defects. This stress defines the true elastic limit and is generally a sizeable share of the macroscopic yield stress. Here we demonstrate that a metallic glass, an amorphous solid with a yield stress in the giga-pascal regime, lacks such a true microscopic elastic limit. Leveraging in-situ coherent x-ray scattering, we uncover a strongly accelerated atomic-scale transport upon the application of a stress as small as 0.005 times the yield stress. With increasing stress levels, the distribution of structural relaxation times changes from compressed exponential to simple exponential form, revealing a stress–temperature equivalence in the time-scale domain. These findings strongly promote a microstructurally heterogeneous picture of metallic glasses, in which a part of the amorphous microstructure controls macroscopic yielding whereas another part admits microplastic flow at any stress.
KW - Metallic glasses
KW - Microstructure
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624530
DO - https://doi.org/10.1016/j.mattod.2024.11.015
VL - 82
SP - 92
EP - 98
PB - Elsevier B.V.
AN - OPUS4-62453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ji, Y.
A1 - Becker, S.
A1 - Lu, Z.
A1 - Mezhov, Alexander
A1 - von Klitzing, R.
A1 - Schmidt, Wolfram
A1 - Stephan, D.
T1 - Effect of resting time on rheological properties of glass bead suspensions - Depletion and bridging force among particles
N2 - The effect of resting time on the rheological properties of cement suspensions is generally explained by early formed structure and overconsumption of polycarboxylate superplasticizers (PCEs). In this paper, we propose that the influence of resting time on the rheological properties is closely related to size variation of non-absorbed PCE. To identify this, glass bead suspensions were prepared with various amounts of PCE and ionic solution, and their rheological properties were evaluated at various times. We found that the yield stress increases with time at higher PCE concentrations and higher ionic strength solutions. Adsorbed PCE during resting tends to bridge the particles rather than disperse them. In addition, it was found that hydrodynamic radius of PCE increased with resting time, and depletion forces resulting from non-absorbed PCE size changes correlate well with the increased yield stress.
KW - Depletion force
KW - Ionic stregth
KW - PCE
KW - Rheology
KW - Resting time
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587193
DO - https://doi.org/10.1111/jace.19469
SN - 0002-7820
SN - 1551-2916
VL - 107
IS - 1
SP - 624
EP - 639
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z.
A1 - Haist, M.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Leinitz, Sarah
A1 - Link, J.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Plank, J.
A1 - Schmidt, Wolfram
A1 - Schilde, C.
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Stephan, D.
T1 - Characterization data of reference cement CEM I 42.5 R used for Priority Program DFG SPP 2005 “Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials”
N2 - A thorough characterization of starting materials is the precondition for further research, especially for cement, which contains various phases and presents quite a complex material for fundamental scientific investigation. In the paper at hand, the characterization data of the reference cement CEM I 42.5 R used within the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The data were collected based on tests conducted by nine research groups involved in this cooperative program. For all data received, the mean values and the corresponding errors were calculated. The results shall be used for the ongoing research within the priority program.
KW - Portland cement
KW - Characterization
KW - DFG SPP 2005
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500849
DO - https://doi.org/10.1016/j.dib.2019.104699
SN - 2352-3409
VL - 27
SP - 104699
PB - Elsevier Inc.
AN - OPUS4-50084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühler, M. M.
A1 - Hollenbach, P.
A1 - Michalski, A.
A1 - Meyer, S.
A1 - Birle, E.
A1 - Off, R.
A1 - Lang, Ch.
A1 - Schmidt, Wolfram
A1 - Cudmani, R.
A1 - Fritz, O.
A1 - Baltes, G.
A1 - Kortmann, G.
T1 - The Industrialisation of Sustainable Construction: A Transdisciplinary Approach to the Large-Scale Introduction of Compacted Mineral Mixtures (CMMs) into Building Construction
N2 - Abstract: Increasing demand for sustainable, resilient, and low-carbon construction materials has highlighted the potential of Compacted Mineral Mixtures (CMMs), which are formulated from various soil types (sand, silt, clay) and recycled mineral waste. This paper presents a comprehensive inter- and transdisciplinary research concept that aims to industrialise and scale up the adoption of CMM-based construction materials and methods, thereby accelerating the construction industry’s systemic transition towards carbon neutrality. By drawing upon the latest advances in soil mechanics, rheology, and automation, we propose the development of a robust material properties database to inform the design and application of CMM-based materials, taking into account their complex, time-dependent behaviour. Advanced soil mechanical tests would be utilised to ensure optimal performance under various loading and ageing conditions. This research has also recognised the importance of context-specific strategies for CMM adoption. We have explored the implications and limitations of implementing the proposed framework in developing countries, particularly where resources may be constrained. We aim to shed light on socio-economic and regulatory aspects that could influence the adoption of these sustainable construction methods. The proposed concept explores how the automated production of CMM-based wall elements can become a fast, competitive, emission-free, and recyclable alternative to traditional masonry and concrete construction techniques.
We advocate for the integration of open-source digital platform technologies to enhance data accessibility, processing, and knowledge acquisition; to boost confidence in CMM-based technologies; and to catalyse their widespread adoption. We believe that the transformative potential of this research necessitates a blend of basic and applied investigation using a comprehensive, holistic, and transfer-oriented methodology. Thus, this paper serves to highlight the viability and multiple benefits of CMMs in construction, emphasising their pivotal role in advancing sustainable development and resilience in the built environment.
KW - Decarbonisation
KW - Circular economy
KW - Recycled materials
KW - Demolition wastes
KW - Low-carbon construction
KW - Building with earth
KW - Compressed earth
KW - Rammed earth
KW - Sustainable construction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583260
DO - https://doi.org/10.3390/su151310677
VL - 15
IS - 13
SP - 1
EP - 25
PB - MDPI
AN - OPUS4-58326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munsch, Sarah Mandy
A1 - Schmidt, Wolfram
A1 - Lorenzoni, Renata
A1 - Telong, Melissa
A1 - Grobla, Lili
A1 - Lauinger, Robert
A1 - Kruschwitz, Sabine
T1 - Investigation of the hydration of clinker‑reduced cementitious binders by 1H NMR relaxometry
N2 - In this paper, we demonstrate the value of 1 H NMR relaxometry for studying the hydration of clinker-reduced, climate-friendly cementitious binders. Our study includes white cement (WC), ordinary Portland cement (OPC), and samples incorporating reactive agro-waste based ashes and non-reactive biochars as supplementary cementitous materials (SCM). NMR measurements were performed over a period of up to 120 h during hydration with an echo time of 50 μ s and a relatively large sample size of 20 mL. The results were compared to heat flow calorimetry (HFC) data, and a detailed comparison with literature data was performed for pure OPC and WC. The results show that time-resolved NMR measurements, especially the analysis of individual NMR signal components assigned to defined 1 H reservoirs, are effective for studying hydration processes. They offer insights into the evolution of the microstrucure and specific chemical phases. NMR provides valuable information and serves as a good complement to HFC. The comparison with data obtained with shorter echo times (40 μs or around 15–45 μs with solid echo sequence) on much smaller samples showed almost identical developments with respect to the T2 distributions. For the SCM samples, NMR results indicated partially accelerated hydration processes compared to classical OPC hydration. One SCM sample acted as a highly reactive pozzolan, showing a similar hydration process to OPC with the strongest effect observed when superplasticizer was added.
Adding biochar delayed C-S-H gel pore formation but significantly increased capillary pores and even free water, likely due to the sponge-like structure.
KW - Nuclear magnetic resonance relaxometry
KW - Heat flow calorimetry
KW - Cement
KW - Hydration
KW - Clinker reduction
KW - Carbon emission
KW - Kinetics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630284
DO - https://doi.org/10.1617/s11527-025-02632-x
SN - 1871-6873
VL - 58
IS - 137
SP - 1
EP - 23
PB - Springer Nature
AN - OPUS4-63028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, K.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
T1 - Effect of agitation during the early‑age hydration on thixotropy and morphology of cement paste
N2 - The effect of agitation during the earlyage hydration on thixotropy and morphology of cement paste prepared with and without superplasticizers (SP) is investigated by applying penetration test, small amplitude oscillatory shear sweep test (SAOS), isothermal calorimetric test, scanning electron microscopy (SEM) and energy dispersive X-ray analyses (EDX). The results show that the agitation of cement paste during the induction period increases the heat flow rate and destroys existing structures of samples without changing the mineral composition of samples. Yet, if the agitation is applied during the acceleration period, the heat flow rate is significantly lowered and the morphology and mineral composition of samples undergo irreversible change, freshly formed syngenite is destroyed and no longer restored.
The penetration force and the static yield stress grow linearly during the induction period and exponentially during the acceleration period. Agitation during the induction period destroys the structure, which causes the static yield stress and the penetration force values becoming nearly equal to zero. However, during the acceleration period, even after agitation the static yield stress and the penetration force exhibit high residual values, which indicates the impact of hydration to the structural build-up.
KW - Hydration · Thixotropy
KW - Agitation
KW - Morphology
KW - Structural build-up
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621189
DO - https://doi.org/10.1617/s11527-024-02504-w
VL - 57
SP - 1
EP - 13
PB - Springer Nature Switzerland AG
CY - Schweiz
AN - OPUS4-62118
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezhov, Alexander
A1 - Bright, Asante
A1 - Schmidt, Wolfram
T1 - Increasing the Incorporation of CO2-Sequestering Materials in Concrete
N2 - Concrete is the most widely used construction material accounting for approximately half of all human production throughout history. The production of one ton of cement emits around 600 kg of CO2. With a global cement production estimate of 4.2 billion tons, this results in about 2.5 billion tons of CO2 emissions. This accounts for roughly 7.2% of the total global carbon emissions in 2021. Strategies to decrease carbon emissions in the cement and concrete industry include carbon capture and storage (CCS), reduced binders like ordinary Portland cement (OPC) clinker and optimizing material use through improved processes and structural design. This also means changing architectural vision [6], avoiding concrete where its structural performance is not required and use alternative materials instead, and optimizing the communication among the entire production value chain.
T2 - 1st International Conference on Net-Zero Built Environment: Innovations in Materials, Structures, and Management Practices (Net-Zero Future 2024)
CY - Oslo, Norway
DA - 19.06.2025
KW - Concrete
KW - CO2-Sequestering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638531
DO - https://doi.org/10.1007/978-3-031-69626-8_4
VL - 237
SP - 39
EP - 48
PB - Springer Nature Switzerland AG
CY - Schweiz
AN - OPUS4-63853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
ED - Schmidt, Wolfram
T1 - Engineering skill requirements to cope with the local and global challenges of the future
N2 - In the 21st century, adequate habitat and functioning infrastructure are critical for global societal and economic stability. In addition, growing urbanisation and environmental pollution cause challenges to societies.
With increasing velocity, humanity faces that the current way of living is not sustainable. Thus, habitat,infrastructure, urbanisation, environment and sustainability are definitively among the most striking challenges of the 21st century.
By consulting, planning, building, maintaining, exploiting and processing of global resources, civil engineers contribute significantly to the existence of these challenges. This is a high responsibility, but due to the heavy involvement, together with adjacent disciplines such as architecture, geosciences, chemistry,
physics, environmental sciences and economics, civil engineers also hold the key to mitigate these challenges and provide a brighter global future.
Solutions towards greener, more sustainable and economically viable materials do exist, and there is ongoing research on how greener technologies can contribute to better livelihood and economic growth, but their level of implementation is limited, a major reason for which is that these approaches require more fundamental understanding rather than standard application.
T2 - ISEE Africa - Innovation, Science, Engineering, Education
CY - Nairobi, Kenya
DA - 30.01.2019
KW - Civil Engineering
KW - Education
KW - Sustainability
KW - Materials
KW - Sciences
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484895
UR - http://isee-africa.com/wp-content/uploads/2019/07/Innovation-Science-Engineering-Education_High-Quality.pdf
SN - 978-3-9818564-2-2
SP - 16
EP - 19
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-48489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Barucker-Sturzenbecher, Meike
A1 - Schmidt, Wolfram
ED - Schmidt, Wolfram
T1 - Learning from the future - How children of Mukuru fancy the city of tomorrow
N2 - Sustainability means meeting the needs of today without compromising the needs of the next generations. How can we meet the needs of the next generations, if we do not even know what these needs are? If we do not listen to the next generation and learn from them? Do we even meet the needs of today for everyone on earth?
T2 - ISEE Africa - Innovation, Science, Engineering, Education
CY - Nairobi, Kenya
DA - 30.01.2019
KW - Urban planning
KW - Concrete
KW - Mukuru
KW - Africa
KW - Sustainability
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484832
UR - http://isee-africa.com/wp-content/uploads/2019/07/Innovation-Science-Engineering-Education_High-Quality.pdf
SN - 978-3-9818564-2-2
SP - 194
EP - 197
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-48483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
A1 - Anniser, J.
A1 - Manful, K.
ED - Schmidt, Wolfram
T1 - A sustainability point of view on horizontal and vertical urban growth
N2 - In many regions of the world the urbanisation process is accelerating dramatically. This puts pressure on urban planners but also politics to develop strategies for sustainable city growth. With the rapidly increasing demand for living space in urban areas, cities typically grow vertically. This is largely driven by real estate markets and sometimes also by the desire for status symbols.
Certainly, vertical urban growth makes sense, when horizontal growth destroys important flora and Fauna (e.g. in rain forest regions), but in many cases vertical growth is result of real-estate business and Expansion limitation due to state or country borders. However, economics and borders are made by humans. They follow human-made rules. Gravity does not. Therefore, from a point of view of sustainable materials and resourceuse, the trending vertical growth of cities may come under scrutiny.
The following aspects should be considered, when a decision is taken between a new quarter with limited number of storeys or a new skyscraper.
T2 - ISEE Africa - Innovation, Science, Engineering, Education
CY - Nairobi, Kenya
DA - 30.01.2019
KW - Urbanisation
KW - Construction
KW - Materials
KW - Sustainability
KW - Carbon emissions
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484848
UR - http://isee-africa.com/wp-content/uploads/2019/07/Innovation-Science-Engineering-Education_High-Quality.pdf
SN - 978-3-9818564-2-2
SP - 189
EP - 193
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-48484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
A1 - Radebe, N.
ED - Schmidt, Wolfram
T1 - Biased by analytical equipment
N2 - Today, in scientific events often a certain separation between researchers from laboratories with highly sophisticated equipment and those from less privileged laboratories can be observed. It is not an uncommon situation that results presented at conferences are rubbished or ridiculed because the investigator only used low-end analytical methods.
The assessment of the study is then biased based on the equipment, regardless of the actual quality of the study.
T2 - ISEE Africa - Innovation, Science, Engineering, Education
CY - Nairobi, Kenya
DA - 30.01.2019
KW - Analytics
KW - Africa
KW - Bias
KW - Science
KW - Research
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484877
UR - http://isee-africa.com/wp-content/uploads/2019/07/Innovation-Science-Engineering-Education_High-Quality.pdf
SN - 978-3-9818564-2-2
SP - 203
EP - 204
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-48487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mendive Tapia, Eduardo
A1 - Patrick, Christopher E
A1 - Hickel, Tilmann
A1 - Neugebauer, Jörg
A1 - Staunton, Julie B
T1 - Quantification of electronic and magnetoelastic mechanisms of first-order magnetic phase transitions from first principles: application to caloric effects in La(FexSi1-x)(13)
N2 - La(FexSi1−x)13 and derived quaternary compounds are well-known for their giant, tunable, magneto- and barocaloric responses around a first-order paramagnetic-ferromagnetic transition near room temperature with low hysteresis. Remarkably, such a transition shows a large spontaneous volume change together with itinerant electron metamagnetic features. While magnetovolume effects are well-established mechanisms driving first-order transitions, purely electronic sources have a long, subtle history and remain poorly understood. Here we apply a disordered local moment picture to quantify electronic and magnetoelastic effects at finite temperature in La(FexSi1−x)13 from first-principles. We obtain results in very good agreement with experiment and demonstrate that the magnetoelastic coupling, rather than purely electronic mechanisms, drives the first-order character and causes at the same time a huge electronic entropy
contribution to the caloric response.
KW - Caloric effects
KW - Ab initio thermodynamics
KW - Magnetoeleastic couplin
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587882
DO - https://doi.org/10.1088/2515-7655/acd027
SN - 2515-7655
VL - 5
IS - 3
SP - 1
EP - 16
PB - IOP Publishing
AN - OPUS4-58788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Das, Amlan
A1 - Dufresne, Eric
A1 - Derlet, Peter M.
A1 - Maaß, Robert
T1 - Intermittent cluster dynamics and temporal fractional diffusion in a bulk metallic glass
N2 - Glassy solids evolve towards lower-energy structural states by physical aging. This can be characterized by structural relaxation times, the assessment of which is essential for understanding the glass’ time-dependent property changes. Conducted over short times, a continuous increase of relaxation times with time is seen, suggesting a time-dependent dissipative transport mechanism. By focusing on micro-structural rearrangements at the atomic-scale, we demonstrate the emergence of sub-diffusive anomalous transport and therefore temporal fractional diffusion in a metallic glass, which we track via coherent x-ray scattering conducted over more than 300,000 s. At the longest probed decorrelation times, a transition from classical stretched exponential to a power-law behavior occurs, which in concert with atomistic simulations reveals collective and intermittent atomic motion. Our observations give a physical basis for classical stretched exponential relaxation behavior, uncover a new power-law governed collective transport regime for metallic glasses at long and practically relevant time-scales, and demonstrate a rich and highly non-monotonous aging response in a glassy solid, thereby challenging the common framework of homogeneous aging and atomic scale diffusion.
KW - Glassy solids
KW - Fractional diffusion
KW - Coherent x-ray scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608015
DO - https://doi.org/10.1038/s41467-024-50758-3
VL - 15
IS - 1
SP - 1
EP - 9
PB - Springer Science and Business Media LLC
AN - OPUS4-60801
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Zengquan
A1 - Riechers, Birte
A1 - Derlet, Peter M.
A1 - Maaß, Robert
T1 - Atomic cluster dynamics causes intermittent aging of metallic glasses
N2 - In the past two decades, numerous relaxation or physical aging experiments of metallic glasses have revealed signatures of intermittent atomic-scale processes. Revealed via intensity cross-correlations from coherent scattering using X-ray photon correlation spectroscopy (XPCS), the observed abrupt changes in the time-domain of atomic motion does not fit the picture of gradual slowing down of relaxation times and their origin continues to remain unclear. Using a binary Lennard-Jones model glass subjected to microsecond-long isotherms, we show here that temporally and spatially heterogeneous atomic-cluster activity at different length-scales drive the emergence of highly non-monotonous intensity cross-correlations. The simulated XPCS experiments reveal a variety of time-dependent intensity-cross correlations that, depending on both the structural evolution and the 𝑞-space sampling, give detailed insights into the possible structural origins of intermittent aging measured with XPCS.
KW - Metallic glasses
KW - Aging
KW - Molecular dynamics
KW - XPCS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595415
DO - https://doi.org/10.1016/j.actamat.2024.119730
SN - 1359-6454
VL - 267
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-59541
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Manzoni, Anna Maria
A1 - Springer, H.
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - Local lattice distortions and chemical short-range order in MoNbTaW
N2 - Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, δexp, is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO.
KW - High Entropy Alloys
KW - Short-range order
KW - Lattice distortions
KW - EXAFS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598164
DO - https://doi.org/10.1080/21663831.2024.2326014
SN - 2166-3831
VL - 12
IS - 5
SP - 346
EP - 354
PB - Taylor & Francis
AN - OPUS4-59816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tehranchi, Ali
A1 - Chakraborty, Poulami
A1 - López Freixes, Martí
A1 - McEniry, Eunan J.
A1 - Gault, Baptiste
A1 - Hickel, Tilmann
A1 - Neugebauer, Jörg
T1 - Tailoring negative pressure by crystal defects: Microcrack induced hydride formation in Al alloys
N2 - Climate change motivates the search for non-carbon-emitting energy generation and storage solutions. Metal hydrides show promising characteristics for this purpose. They can be further stabilized by tailoring the negative pressure of microstructural and structural defects. Using systematic ab initio and atomistic simulations, we demonstrate that an enhancement in the formation of hydrides at the negatively pressurized tip region of the microcrack is feasible by increasing the mechanical tensile load on the specimen. The theoretical predictions have been used to reassess and interpret atom probe tomography experiments for a high-strength 7XXX-aluminium alloy that show a substantial enhancement of hydrogen concentration at structural defects near a stress-corrosion crack tip. These results contain important implications for enhancing the capability of metals as H-storage materials.
KW - Physics and Astronomy (miscellaneous)
KW - Hydrogen storage
KW - Ab initio Simulation
KW - Microcracks
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587878
DO - https://doi.org/10.1103/PhysRevMaterials.7.105401
SN - 2475-9953
VL - 7
IS - 10
SP - 105401-1
EP - 105401-12
PB - American Physical Society (APS)
AN - OPUS4-58787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, M.
A1 - Schubert, Nils
A1 - Günster, Jens
A1 - Stawarczyk, B.
A1 - Zocca, Andrea
T1 - Additive manufacturing of glass-ceramic dental restorations by layerwise slurry deposition (LSD-print)
N2 - This study is dedicated to the additive manufacturing of a feldspar glass-ceramic for dental applications by LSD-print (layerwise slurry deposition) technology, a variation of binder jetting using water-based ceramic slurries as feedstock. This technology was investigated for the manufacturing of single tooth restoration demonstrators with good aesthetic properties, and to compare the additively manufactured material with a commercial reference. Model restorations with > 99 % relative density were processed with a debinding and firing cycle of 45 min, however the whole process chain accounts for up to 30 hours. Significant differences between LSD-printed and reference materials were found for fracture strength, fracture toughness and Martens parameters. Printing orientation affected shrinkage and fracture strength, but not fracture toughness and Martens parameters. Nevertheless, the results suggest that the LSD-print technology processing the developed slurry is a promising option for manufacturing dental restorations meeting class 1a requirements according to DIN EN ISO 6871:2019–01.
KW - Additive Manufacturing
KW - 3D-printing
KW - LSD-print
KW - Dental ceramics
KW - Glass-ceramic
KW - Debinding
KW - Firing
KW - Sinter-crystallization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624768
DO - https://doi.org/10.1016/j.jeurceramsoc.2025.117235
VL - 45
IS - 7
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-62476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Hidde, Gundula
A1 - Schenderlein, Matthias
A1 - Özcan Sandikcioglu, Özlem
T1 - Effect of organic conditioning layers adsorbed on stainless steel AISI 304 on the attachment and biofilm formation of electroactive bacteria Shewanella putrefaciens CN32
N2 - The initial attachment and subsequent biofilm formation of electroactive bac-teriaShewanella putrefaciensCN32 was investigated to clarify the influence oforganic conditioning layers. A selection of macromolecules and self-assembledmonolayers (SAMs) of different chain lengths and functional groups were pre-pared and characterized by means of infrared spectroscopy in terms of theirchemistry. Surface energy and Zeta (ζ-) potential of the conditioning layers wasdetermined with contact angle and streaming current measurements. Amongthe studied surface parameters, a high polar component and a high ratio ofpolar-to-disperse components of the surface energy has emerged as a successfulindicator for the inhibition of the initial settlement ofS. putrefacienson stainlesssteel AISI 304 surfaces. Considering the negative surface charge of planktonicS. putrefacienscells, and the strong inhibition of cell attachment by positivelycharged polyethylenimine (PEI) conditioning layers, our results indicate thatelectrostatic interactions do play a subordinate role in controlling the attach-ment of this microorganism on stainless steel AISI 304 surfaces. For the biofilmformation, the organization of the SAMs affected the local distribution of thebiofilms. The formation of three-dimensional and patchy biofilm networks waspromoted with increasing disorder of the SAMs.
KW - Bacterial attachment
KW - Conditioning films
KW - Self-assembled monolayers
KW - Stainless steel
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559887
DO - https://doi.org/10.1002/eng2.12458
VL - 4
IS - 1
SP - 1
EP - 12
PB - Wiley online library
AN - OPUS4-55988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Urban, Klaus
A1 - Ackerhans, C.
A1 - Gorbushina, Anna
T1 - Analysis of Carbon and Nitrogen from Atmospheric Sources by Bulk Deposition Sampling at various locations in Germany
N2 - Atmospheric deposition of particulate matter is an important indicator of air pollution and a significant factor in material surface fouling. The elemental composition of this nutrient-containing dust depends largely on the exposure region and time as well as on climate. Therefore, in this paper we report an analysis of atmospheric pollutions with a self-made low-cost bulk deposition sampler directed at sampling deposition via air transport and rainfall. We used the device in diverse environments - thus comparing an urban region, an area surrounded by forest and an area mainly dominated by agriculture. The total organic carbon (TOC) and total nitrogen (TN) amounts were selected as indicator parameters and analyzed in a biweekly rhythm for three and a half and two years, respectively. The TOC value responded to particulate matter in the urban area, especially significant were the influences of the New Year's firework in urban and pollen in the rural forest area. In contrast, the TN value was more under the influence of the nitrogen emissions in the agriculture-dominated area. However, the TN value did not correlate with the NOx values in the urban area because the atmospheric nitrogen emissions in the city might originate from various emission sources. Summarizing, the TOC and TN values of the self-made low-cost bulk deposition sampler were in good agreement with environmental events of their immediate surrounding. Moreover, the selected containers and sampling procedures are universally applicable to monitor and analyze organic as well as inorganic parameters (e.g. metal ions) of atmospheric deposition.
KW - Passive sampling
KW - Biomonitoring
KW - Air Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609373
DO - https://doi.org/10.1016/j.envadv.2024.100583
SN - 2666-7657
VL - 17
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-60937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Almalla, A.
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - In Situ Atomic Force Microscopy Analysis of the Corrosion Processes at the Buried Interface of an Epoxy-like Model Organic Film and AA2024-T3 Aluminum Alloy
N2 - The application of characterization methods with high spatial resolution to the analysis of buried coating/metal interfaces requires the design and use of model systems. Herein, an epoxy-like thin film is used as a model coating resembling the epoxy-based coatings and adhesives widely used in technical applications. Spin coating is used for the deposition of a 30 nm-thin bilayer (BL) composed of poly-(ethylenimine) (PEI) and poly[(o-cresyl glycidyl ether)-co-formaldehyde] (CNER). Fourier-transform infrared spectroscopy (FTIR) results confirm that the exposure of coated AA2024-T3 (AA) samples to the corrosive electrolyte solution does not cause the degradation of the polymer layer. In situ atomic force microscopy (AFM) studies are performed to monitor local corrosion processes at the buried interface of the epoxy-like film and the AA2024-T3 aluminum alloy surface in an aqueous electrolyte solution. Hydrogen evolution due to the reduction of water as the cathodic corrosion reaction leads to local blister formation. Based on the results of the complementary energy-dispersive X-ray spectroscopy (EDX) analysis performed at the same region of interest, most of the hydrogen evolved originates at the vicinity of Mg-containing intermetallic particles.
KW - Scanning Kelvin probe force microscopy
KW - Aluminum alloys
KW - Buried interfaces
KW - In situ atomic force microscopy
KW - Local corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546932
DO - https://doi.org/10.1002/adem.202101342
SN - 1438-1656
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-54693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - von der Au, Marcus
A1 - Dietrich, P. M.
A1 - Radnik, Jörg
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - The comparison of the corrosion behavior of the CrCoNi medium entropy alloy and CrMnFeCoNi high entropy alloy
N2 - This work presents the determination of the corrosion characteristics of CrCoNi (medium entropy alloy) and CrMnFeCoNi (high entropy alloy) in 0.1 M NaCl and 0.1 M H2SO4. The morphology and chemical composition of the oxide layers formed on CrCoNi and CrMnFeCoNi were comparatively analyzed by scanning Kelvin probe microscopy (SKPFM) and scanning electron microscopy (SEM) and supported with chemical analysis by means of inductively coupled plasma mass spectrometry (ICP-MS) and X-Ray photoelectron spectroscopy (XPS). The analysis of the 3p core level peaks showed that the oxide layer (native and after anodic passivation) on CrCoNi consisted mainly of Cr oxides, while the oxide layer on CrMnFeCoNi was primarily composed of a mixture of Cr and Fe oxides. In addition, XPS was utilized to assess the oxide layer thicknesses. These results were compared to the thicknesses obtained by means of electrochemical impedance spectroscopy (EIS), with both approaches yielding values up to about 4 nm depending on the electrolyte and the alloy. Cyclic polarization measurements indicated superior corrosion resistance of CrCoNi in both aqueous environments compared to CrMnFeCoNi, as well as to AISI 304 stainless steel.
KW - Medium entropy alloy
KW - High entropy alloy
KW - SKPFM
KW - XPS
KW - Passivation
KW - Corrosion
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559902
DO - https://doi.org/10.1016/j.apsusc.2022.154171
SN - 0169-4332
VL - 601
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-55990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Selbmann, L.
A1 - Benkő, Z.
A1 - Coleine, C.
A1 - de Hoog, S.
A1 - Donati, C.
A1 - Druzhinina, I.
A1 - Emri, T.
A1 - Ettinger, C. L.
A1 - Gladfelter, A. S.
A1 - Gorbushina, Anna
A1 - Grigoriev, I. V.
A1 - Grube, M.
A1 - Gunde-Cimerman, N.
A1 - Karányi, Z. A.
A1 - Kocsis, B.
A1 - Kubressoian, T.
A1 - Miklós, I.
A1 - Miskei, M.
A1 - Muggia, L.
A1 - Northen, T.
A1 - Novak-Babič, M.
A1 - Pennacchio, C.
A1 - Pfliegler, W. P.
A1 - Pòcsi, I.
A1 - Prigione, V.
A1 - Riquelme, M.
A1 - Segata, N.
A1 - Schumacher, Julia
A1 - Shelest, E.
A1 - Sterflinger, K.
A1 - Tesei, D.
A1 - U’Ren, J. M.
A1 - Varese, G. C.
A1 - Vázquez-Campos, X.
A1 - Vicente, V. A.
A1 - Souza, E. M.
A1 - Zalar, P.
A1 - Walker, A. K.
A1 - Stajich, J. E.
T1 - Shed Light in the DaRk LineagES of the Fungal Tree of Life—STRES
N2 - The polyphyletic group of black fungi within the Ascomycota (Arthoniomycetes, Dothideomycetes, and Eurotiomycetes) is ubiquitous in natural and anthropogenic habitats. Partly because of their dark, melanin-based pigmentation, black fungi are resistant to stresses including UV- and ionizing-radiation, heat and desiccation, toxic metals, and organic pollutants. Consequently, they are amongst the most stunning extremophiles and poly-extreme-tolerant organisms on Earth. Even though ca. 60 black fungal genomes have been sequenced to date, [mostly in the family Herpotrichiellaceae (Eurotiomycetes)], the class Dothideomycetes that hosts the largest majority of extremophiles has only been sparsely sampled. By sequencing up to 92 species that will become reference genomes, the “Shed light in The daRk lineagES of the fungal tree of life” (STRES) project will cover a broad collection of black fungal diversity spread throughout the Fungal Tree of Life. Interestingly, the STRES project will focus on mostly unsampled genera that display different ecologies and life-styles (e.g., ant- and lichen-associated fungi, rock-inhabiting fungi, etc.). With a resequencing strategy of 10- to 15-fold depth coverage of up to ~550 strains, numerous new reference genomes will be established. To identify metabolites and functional processes, these new genomic resources will be enriched with metabolomics analyses coupled with transcriptomics experiments on selected species under various stress conditions (salinity, dryness, UV radiation, oligotrophy). The data acquired will serve as a reference and foundation for establishing an encyclopedic database for fungal metagenomics as well as the biology, evolution, and ecology of the fungi in extreme environments.
KW - Adaptation
KW - Black fungi
KW - Dothideomycetes
KW - Eurotiomycetes
KW - Extremophiles
KW - Genomics
KW - Metabolomics
KW - Secondary metabolites
KW - Stress conditions
KW - Transcriptomics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519328
DO - https://doi.org/10.3390/life10120362
VL - 10
IS - 12
SP - 362
PB - MDPI
CY - Basel
AN - OPUS4-51932
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stohl, Leonie
A1 - Tonon, Chiara
A1 - Cook, Jake
A1 - Gorbushina, Anna
A1 - Dehn, Frank
A1 - von Werder, Julia
A1 - Manninger, Tanja
T1 - Understanding bioreceptivity of concrete: material design and characterization
N2 - The climate crisis is driving an increasing demand for ecologically oriented concepts. In the building sector, this demand includes not only the use of environmentally friendly materials but also the greening of urban areas. One promising approach is the development of bioreceptive concrete façades, which support the growth of green biofilms directly on their surfaces. These innovative façades are anticipated to deliver benefits comparable to those of macroscopically greened façades, such as enhanced biodiversity and improved air quality, while offering the advantages of being more self-sustaining and stable systems once fully established.
However, the development of bioreceptive concrete presents substantial challenges. Due to the interdisciplinarity and novelty of this field, standardized methods for material characterization and bioreceptivity assessment are currently lacking. This study proposes an approach for evaluating surface properties crucial for bioreceptivity, developed on differently structured samples of ultra-high-performance concrete (UHPC). Existing methods and standards from concrete technology are critically reviewed and, where necessary, modified to meet the unique requirements of measuring bioreceptive material properties. Special attention is given to the surface pH value and water retention characteristics, as these are essential for promoting microbial growth and ensuring the long-term stability of green biofilms. The observed surface characteristics vary according to the imprinted surface structures, offering a spectrum of material properties and enabling the evaluation of their impact on bioreceptivity. The findings presented form the foundation for subsequent laboratory weathering experiments, which will be discussed in a complementary publication.
KW - Novel methods
KW - Bioreceptivity testing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655023
DO - https://doi.org/10.1617/s11527-025-02863-y
SN - 1359-5997
VL - 58
SP - 1
EP - 18
PB - Springer Science and Business Media LLC
AN - OPUS4-65502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rashidi, Reza
A1 - Vaerst, Olivia
A1 - Riechers, Birte
A1 - Rösner, Harald
A1 - Wilde, Gerhard
A1 - Maaß, Robert
T1 - Atomic-scale strain fluctuations as an origin for elastic microstructures in metallic glasses
N2 - Metallic glasses (MGs) exhibit an elastic microstructure that spans from a few to hundreds of nanometers, the origin of which continues to remain poorly understood. Here we employ four-dimensional scanning transmission electron microscopy (4D-STEM) on a Zr65Cu25Al10 (at. %) bulk MG. Mapping local diffraction patterns over representative areas also probed elastically with automated nanoindentation, two comparable correlation length scales have been identified. Specifically, local diffraction patterns are analyzed with respect to their ellipticity, revealing systematic fluctuations between positive and negative volumetric strains. A power spectrum analysis of the strain fluctuations returns a dominant length scale of the order of 100 nm, which is very much compatible with what elastic property mapping indicates. Annealing reduces the magnitude of the statistical strain fluctuations, without strongly affecting the associated fluctuation length scale. These findings demonstrate that atomic-scale strains are very likely the origin of the structurally unexpected large elastic fluctuations obtained in nanoscale contact mechanics experiments.
KW - Metallic glass
KW - 4D-STEM
KW - Strain anisotropy
KW - Nanoindentation
KW - Elastic microstructure
KW - Heterogeneities
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654991
DO - https://doi.org/10.1016/j.actamat.2026.121982
SN - 1359-6454
VL - 308
SP - 1
EP - 8
PB - Elsevier Inc.
AN - OPUS4-65499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lanzino, Maria Carolina
A1 - Le, Long-Quan R. V.
A1 - Wilbig, Janka
A1 - Rheinheimer, Wolfgang
A1 - Seidenstuecker, Michael
A1 - Günster, Jens
A1 - Killinger, Andreas
T1 - Thin GB14 coatings on implants using HVSFS
N2 - Enhancing osseointegration, the process by which medical implants securely bond to bone, is crucial for improving patient outcomes in orthopedics and dental surgery. Calcium alkali orthophosphates, with their superior bioactivity, resorbability, and chemical resemblance to bone minerals, have emerged as promising candidates for implant coatings. These materials offer improved solubility and lower melting points due to the substitution of calcium with potassium and sodium, along with the addition of magnesium oxide. This study investigates GB14 calcium alkali orthophosphate coatings applied via High Velocity Suspension Flame Spraying (HVSFS), a technique that enables precise control over coating properties. A porosity target of >10% was set to promote bone growth, and we achieved porosities up to 13%, ensuring better cell penetration and stability at the implant-bone interface. Coatings were produced using different gas parameters and distances, with their microstructure and phase composition analyzed using scanning electron microscope (SEM), Vickers hardness testing and X-ray diffraction (XRD). Additionally, roughness and porosity were also assessed. Different coating’s microstructures were achieved by varying stand-off distance and gas parameters. Increasing stand-off distance while reducing gas stoichiometry enabled the production of calcium alkali orthophosphate coatings with fewer cracks, higher porosity and a hardness level comparable to that of state-of-the-art tricalcium phosphate (TCP) coatings. The sample with optimized properties in terms of achieved microstructure and topography was selected for in vitro testing using MG63 osteosarcoma cells to evaluate cell proliferation and adhesion. WST (I) assay, LDH assay, and live/dead staining confirmed the biocompatibility of the coatings, highlighting the potential of HVSFS to enhance osseointegration and outperform conventional methods in implantology. No relevant cytotoxicity could be shown and cells show a good proliferation over time. These results highlight thus the potential of HVSFS to produce thin, bioactive and resorbable coatings to enhance osseointegration.
KW - Bio ceramics
KW - Spray coating
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623983
DO - https://doi.org/10.3389/fmats.2024.1522447
SN - 2296-8016
VL - 11
IS - 1522447
SP - 1
EP - 14
PB - Frontiers Media SA
AN - OPUS4-62398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wen, Keqing
A1 - Gorbushina, Anna
A1 - Schwibbert, Karin
A1 - Bell, Jérémy
T1 - Microfluidic platform with precisely controlled hydrodynamic parameters and integrated features for generation of microvortices to accurately form and monitor biofilms in flow
N2 - Microorganisms often live in habitats characterized by fluid flow, and their adhesion to surfaces in industrial systems or clinical settings may lead to pipe clogging, microbially influenced corrosion, material deterioration, food spoilage, infections, and human illness. Here, a novel microfluidic platform was developed to investigate biofilm formation under precisely controlled (i) cell concentration, (ii) temperature, and (iii) flow conditions. The developed platform central unit is a single-channel microfluidic flow cell designed to ensure ultrahomogeneous flow and condition in its central area, where features, e.g., with trapping properties, can be incorporated. In comparison to static and macroflow chamber assays for biofilm studies, microfluidic chips allow in situ monitoring of biofilm formation under various flow regimes and have better environment control and smaller sample requirements. Flow simulations and experiments with fluorescent particles were used to simulate bacteria flow in the platform cell for calculating flow velocity and direction at the microscale level. The combination of flow analysis and fluorescent strain injection in the cell showed that microtraps placed at the center of the channel were efficient in capturing bacteria at determined positions and to study how flow conditions, especially microvortices, can affect biofilm formation. The microfluidic platform exhibited improved performances in terms of homogeneity and robustness for in vitro biofilm formation. We anticipate the presented platform to be suitable for broad, versatile, and high-throughput biofilm studies at the microscale level.
KW - Topographical pattern
KW - E. coli
KW - Fluorescence
KW - Bacteria trapping
KW - Particle velocimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610450
DO - https://doi.org/10.1021/acsbiomaterials.4c00101
SN - 2373-9878
VL - 10
IS - 7
SP - 4626
EP - 4634
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-61045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna Christiane
A1 - Schwentenwein, Martin
A1 - Bermejo, Raúl
A1 - Günster, Jens
T1 - Hybridizing Lithography-Based Ceramic Additive Manufacturing with Two-Photon-Polymerization
N2 - Stereolithography processes such as lithography-based ceramic manufacturing (LCM) are technologies that can produce centimeter-sized structures in a reasonable time frame. However, for some parts specifications, they lack resolution. Two-photon-polymerization (2PP) ensures the highest geometric accuracy in additive manufacturing so far. Nevertheless, building up parts in sizes as large as a few millimeters or even centimeters is a time-consuming process, which makes the production of 2PP printed parts very costly. Regarding feedstock specification, the requirements for 2PP are different to those for LCM, and generally, feedstocks are designed to meet requirements for only one of these manufacturing technologies. In an attempt to fabricate highly precise ceramic components of a rather large size, it is necessary to develop a feedstock that suits both light-based technologies, taking advantage of LCM’s higher productivity and 2PP’s accuracy. Hybridization should bring the desired precision to the region of interest on reasonably large parts without escalating printing time and costs. In this study, specimens gained from a transparent feedstock with yttria stabilized zirconia (YSZ) particles of 5 nm at 70 wt% were presented. The resin was originally designed to suit 2PP, while being also printable with LCM. This work demonstrates how hybrid parts can be sintered into full YSZ ceramics.
KW - Additive Manufacturing
KW - Transparent ceramic
KW - Nano-powder
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584541
DO - https://doi.org/10.3390/app13063974
SN - 2076-3417
VL - 13
IS - 6
SP - 1
EP - 9
PB - MDPI
CY - Basel
AN - OPUS4-58454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Almalla, A.
A1 - Hertwig, Andreas
A1 - Fischer, Daniel
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - Development of layer-by-layer assembled thin coatings on aluminium alloy AA2024-T3 for high resolution studies of local corrosion processes
N2 - The aim of this study is to develop nanometer-thin epoxy-based films on aluminium alloy AA2024-T3 as a model coating system for high resolution corrosion studies. Spin coating was used for the layer-by-layer (LbL) deposition of poly-(ethylenimine) (PEI) and poly([o-cresyl glycidyl ether]-co-formaldehyde) (CNER) bilayers. The film chemistry and the cross-linking process were characterized by means of Fourier-transform infrared spectroscopy (FTIR).
Ellipsometric data confirmed the linear increase of film thickness. The potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) results indicate the improvement of the film barrier properties with increasing film thickness. Mapping of the topography and the volta potential was performed by means of scanning Kelvin probe force microscopy (SKPFM).
The results indicate the presence of a homogeneous film structure, while the intermetallic phases can still be identified below the coating. The SKPFM Analysis confirmed that the model films are suitable for investigation of corrosion processes at the coating/metal interface.
KW - Spectroscopy
KW - Coatings
KW - Electrochemistry
KW - Microscopy
KW - Resins
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514627
DO - https://doi.org/10.1002/app.49826
SN - 0021-8995
VL - 137
IS - 48
SP - e49826-1
EP - e49826-9
PB - Wiley
CY - New York, NY
AN - OPUS4-51462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - Morell, Daniel
A1 - von der Au, Marcus
A1 - Wittstock, Gunther
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - Transpassive Metal Dissolution vs. Oxygen Evolution Reaction: Implication for Alloy Stability and Electrocatalysis
T1 - Transpassive Metallauflösung vs. Sauerstoffentwicklung:
Auswirkungen auf Legierungsstabilität und Elektrokatalyse
N2 - Multi-principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER-onset detection, and quantitative chemical analysis with inductively coupled-mass spectrometry (ICP-MS) and ultraviolet visible light (UV-Vis) spectroscopy to elucidate metal dissolution processes. In-situ electrochemical atomic force microscopy (EC-AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors.
N2 - Multi-Hauptelement-Legierungen (MPEAs) gewinnen in der Korrosions- und Elektrokatalyseforschung aufgrund ihrer elektrochemischen Stabilität über einen breiten pH-Bereich und der Vielfalt der möglichen chemischen Zusammensetzungen zunehmend an Interesse. In unseren Untersuchungen mit der äquimolaren CrCoNi-Legierung in einem sauren Elektrolyten (0.1 M NaCl, pH 2) beobachteten wir eine signifikante Metallauflösung, die mit der Sauerstoffentwicklungsreaktion (OER) im transpassiven Bereich einhergeht, obwohl in zyklischen Polarisationskurven keine Hysterese auftrat oder andere offensichtliche Korrosionsindikatoren vorlagen. In diesem Artikel wird ein Charakterisierungskonzept eingeführt, dass die Beiträge der OER und der Legierungsauflösung differenziert. Hierfür kommt die elektrochemische Rastermikroskopie (SECM) zum Nachweis des Beginns der OER und die quantitative chemische Analyse mit induktiv gekoppelter Massenspektrometrie (ICP-MS) und UV/Vis-Spektrometrie zur Aufklärung der Metallauflösungsprozesse zum Einsatz. Die elektrochemische In situ-Atomkraftmikroskopie (EC-AFM) zeigte, dass die intergranulare Korrosion der dominierende Mechanismus der transpassive Metallauflösung von CrCoNi ist. Diese Ergebnisse besitzen erhebliche Auswirkungen für die Beurteilung der Stabilität von MPEAs in Korrosionssystemen und der Stromausbeute von OER-Katalysatoren auf der Basis von MPEAs. Die Daten unterstreichen die Notwendigkeit der analytischen Bestimmung von Metallionen, die von MPEA-Elektroden freigesetzt werden. Die Freisetzung von Übergangsmetallionen verringert nicht nur die Stromausbeute von Elektrolyseuren, sondern kann zu einer Schädigung von Membranen in elektrochemischen Reaktoren führen.
KW - Transpassive dissolution
KW - Corrosion
KW - Multi-prinicpal element alloys (MPEAs)
KW - Passivation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597045
DO - https://doi.org/10.1002/anie.202317058
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-59704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Catanzaro, Ilaria
A1 - Gorbushina, Anna
A1 - Onofri, Silvano
A1 - Schumacher, Julia
T1 - 1,8‐Dihydroxynaphthalene (DHN) melanin provides unequal protection to black fungi Knufia petricola and Cryomyces antarcticus from UV‐B radiation
N2 - Black fungi on rock surfaces endure a spectrum of abiotic stresses, including UV radiation. Their ability to tolerate extreme conditions is attributed to the convergent evolution of adaptive traits, primarily highly melanized cell walls. However, studies on fungal melanins have not provided univocal results on their photoprotective functions. Here, we investigated whether the black fungi Knufia petricola and Cryomyces antarcticus only use DHN melanin or may employ alternative mechanisms to counteract UV‐induced damage. For this, melanized wild types and non‐melanized Δpks1 mutants were exposed to different doses of UV‐B (312 nm) followed by incubation in constant darkness or in light–dark cycles to allow light‐dependent DNA repair by photolyases (photoreactivation). C. antarcticus could tolerate higher UV‐B doses but was sensitive to white light, whereas K. petricola showed the opposite trend. DHN melanin provided UV‐B protection in C. antarcticus, whereas the same pigment or even carotenoids proved ineffective in K. petricola. Both fungi demonstrated functional photoreactivation in agreement with the presence of photolyase‐encoding genes. Our findings reveal that although the adaptive trait of DHN melanization commonly occurs across black fungi, it is not equally functional and that there are species‐specific adaptations towards either UV‐induced lesion avoidance or repair strategies.
KW - Rock-inhabiting Ascomycetes
KW - Pigment
KW - Photoprotection
KW - Photolyase
KW - Disinfection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616859
DO - https://doi.org/10.1111/1758-2229.70043
VL - 16
IS - 6
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-61685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna C.
A1 - Riechers, Birte
A1 - Pauw, Brian Richard
A1 - Maaß, Robert
A1 - Günster, Jens
T1 - Microplastic response of 2PP‐printed ceramics
N2 - AbstractTwo‐photon polymerization (2PP) additive manufacturing (AM) utilizes feedstocks of ceramic nanoparticles of a few nanometers in diameter, enabling the fabrication of highly accurate technical ceramic design with structural details as small as 500 nm. The performance of these materials is expected to differ from conventional AM ceramics, as nanoparticles and three‐dimensional printing at high resolution introduce new microstructural aspects. This study applies 2PP‐AM of yttria‐stabilized zirconia to investigate the mechanical response behavior under compressive load, probing the influence of smallest structural units induced by the line packing during the printing process, design of sintered microblocks, and sintering temperature and thereby microstructure. We find a dissipative mechanical response enhanced by sintering at lower temperatures than conventional. The pursued 2PP‐AM approach yields a microstructured material with an increased number of grain boundaries that proposedly play a major role in facilitating energy dissipation within the here printed ceramic material. This microplastic response is further triggered by the filigree structures induced by hollow line packing at the order of the critical defect size of ceramics. Together, these unique aspects made accessible by the 2PP‐AM approach contribute to a heterogeneous nano‐ and microstructure, and hint toward opportunities for tailoring the mechanical response in future ceramic applications.
KW - Manufacturing
KW - Mechanical properties
KW - Microstructure
KW - Plasticity
KW - Zirconia: yttria stabilized
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605176
DO - https://doi.org/10.1111/jace.19849
SN - 1551-2916
VL - 107
IS - 10
SP - 6636
EP - 6645
PB - Wiley
CY - Oxford
AN - OPUS4-60517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wild, B.
A1 - Gerrits, Ruben
A1 - Bonneville, S.
T1 - The contribution of living organisms to rock weathering in the critical zone
N2 - Rock weathering is a key process in global elemental cycling. Life participates in this process with tangible consequences observed from the mineral interface to the planetary scale. Multiple lines of evidence show that microorganisms may play a pivotal—yet overlooked—role in weathering. This topic is reviewed here with an emphasis on the following questions that remain unanswered: What is the quantitative contribution of bacteria and fungi to weathering? What are the associated mechanisms and do they leave characteristic imprints on mineral surfaces or in the geological record? Does biogenic weathering fulfill an ecological function, or does it occur as a side effect of unrelated metabolic functions and biological processes? An overview of efforts to integrate the contribution of living organisms into reactive transport models is provided. We also highlight prospective opportunities to harness microbial weathering in order to support sustainable agroforestry practices and mining activities, soil remediation, and carbon sequestration.
KW - Bio-weathering
KW - Fungi
KW - Mineral
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566748
DO - https://doi.org/10.1038/s41529-022-00312-7
SN - 2397-2106
VL - 6
SP - 1
EP - 16
PB - Macmillan
CY - London
AN - OPUS4-56674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, Juan-Carlos
A1 - Baasch, Julian
A1 - Stapperfend, Simon
A1 - Facchini, Leonardo
A1 - Linke, Stefan
A1 - Stoll, Enrico
A1 - Günster, Jens
T1 - Laser Melting vs. Laser Sintering: Large Area Heat Processing of Lunar South Pole Simulant
N2 - A key component of future lunar missions is the concept of In-Situ Resource Utilization (ISRU), which involves the use of local resources to support human missions and reduce dependence on Earth-based supplies. This paper investigates the thermal processing capability of lunar regolith without the addition of binders, with a focus on large-scale applications for the construction of lunar habitats and infrastructure. The study used a simulant of lunar regolith found on the Schrödinger Basin in the South Pole region. This regolith simulant consists of 20 wt% basalt and 80 wt% anorthosite. Experiments were conducted using a high power CO2 laser to sinter and melt the regolith in a 80 mm diameter laser spot to evaluate the effectiveness of direct large area thermal processing. Results indicated that sintering begins at approximately 1,180 °C and reaches full melt at temperatures above 1,360 °C. Sintering experiments with this material revealed the formation of dense samples up to 11 mm thick, while melting experiments successfully produced larger samples by overlapping molten layers and additive manufacturing up to 50 mm thick. The energy efficiency of the sintering and melting processes was compared. The melting process was about 10 times more energy efficient than sintering in terms of material consolidation, demonstrating the promising potential of laser melting technologies of anorthosite-rich regolith for the production of structural elements.
KW - Additive Manufacturing
KW - Laser melting
KW - ISRU
KW - Moon
KW - Regolith
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639614
DO - https://doi.org/10.1016/j.amf.2025.200226
SN - 2950-4317
VL - 4
IS - 3
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-63961
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
T1 - Application of Elastic Reverse Time Migration to Ultrasonic Echo Data from Concrete Structures
N2 - To enhance ultrasonic imaging of concrete structures, we adapted the geophysical migration method, Reverse Time Migration (RTM), for non-destructive testing (NDT) in civil engineering. First, two 2D elastic RTM algorithms, each considering different wave types, were implemented and evaluated with synthetic ultrasonic data. The algorithm that best resolved numerical concrete structures was subsequently applied to real ultrasonic data from a concrete specimen. Compared with conventional synthetic aperture focusing technique (SAFT) imaging, elastic RTM reproduced a greater number of structural features in both the numerical model and the concrete specimen. In particular, elastic RTM reconstructed vertical interfaces as well as hidden lower edges of modeled cavities and tendon ducts. Notably, imaging the full cross-sections of tendon ducts, which enables direct diameter estimation, represents a novel achievement for ultrasonic NDT.
T2 - NDT-CE 2025 - The International Symposium on Nondestructive Testing in Civil Engineering
CY - Izmir, Turkey
DA - 24.09.2025
KW - Concrete Structures
KW - Ultrasonic Echo Technique
KW - Ultrasonic Imaging
KW - Elastic Reverse Time Migration
KW - Synthetic Aperture Focusing Technique
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650350
DO - https://doi.org/10.58286/31680
SN - 1435-4934
SP - 1
EP - 3
PB - e-Journal of Nondestructive Testing
CY - www.ndt.net
AN - OPUS4-65035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naumann, Kathrin
A1 - Tichter, Tim
A1 - Nielsen, Rasmus S.
A1 - Seger, Brian
A1 - Hansen, Ole
A1 - Chorkendorff, Ib
A1 - Vesborg, Peter C. K.
T1 - Protection Materials on III–V Semiconductors for Photoelectrochemical CO Reduction
N2 - Tantalum oxide (TaOx) and amorphous titanium dioxide (TiO2) are employed as protection materials for commercial GaInP/GaAs/Ge triple-junction solar cells to facilitate the unbiased photoelectrochemical reduction of carbon monoxide on nanostructured copper particles. It has been found that a photoelectrode protected by a 150 nm-thick layer of TiO2, capped with 8 nm TaOx, and decorated with copper nanocubes in the size of 150 nm can successfully drive the photoelectrochemical conversion of carbon monoxide to ethylene. Implemented into a photoelectrochemical flow reactor, which continuously supplies the active interface with CO-saturated electrolyte, the device achieves a faradaic efficiency of 24% under AM1.5G conditions. Direct attachment of the copper nanocubes to a protection layer of TiO2 in the absence of TaOx results in a strong hydrogen evolution reaction (HER) and no CO reduction products are found. This unexpected loss in selectivity is studied via post-operando X-ray photoemission spectroscopy and ion-scattering spectroscopy. No modifications in the redox state of TiO2 orsigns of H intercalation are found, while the preferential redeposition of small Cu nanoparticles is considered possible. This increasein HER appears specific for TiO2, as additional, purely electroanalytical experiments using tantalum oxide or carbon as a support layer for Cu nanocubes can produce ethylene effectively.
KW - Photoelectrochemistry
KW - Carbon Monoxide Reduction
KW - Protection Material
KW - Multi‐junction
KW - Copper Catalyst
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618712
DO - https://doi.org/10.1021/acs.jpcc.4c04782
SP - 1
EP - 10
PB - American Chemical Society (ACS)
AN - OPUS4-61871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prenner, Stefanie
A1 - Part, Florian
A1 - Jandric, Aleksander
A1 - Bordes, Arnaud
A1 - Leonhardt, Robert
A1 - Jung-Waclik, Sabine
A1 - Huber-Humer, Marion
ED - Djebali, Ridha
T1 - Enabling Circular Business Models: Preconditions and Key Performance Indicators for the Market Launch of Repurposed Second‐Life Lithium‐Ion Batteries From Electric Vehicles
N2 - With the rise of electric vehicles (EVs) and thus lithium‐ion batteries (LIBs), the number of end‐of‐life (EoL) LIBs after their first life in EVs is about to increase significantly. These end‐of‐first‐life (EoFL) EV LIBs still have sufficient energy density for less‐demanding second‐life applications like stationary battery energy storage systems (BESSs) or mobile applications (e.g., forklifts, tools). Repurposing EoFL EV LIBs extends their lifespan, offering sustainability benefits and supporting several United Nations (UN) Sustainable Development Goals (SDGs). However, prevailing market entry barriers, such as high repurposing costs, little information on battery history and aging, or lacking performance indicators, hinder the widespread implementation of second‐life applications. Thus, this study aims to identify preconditions for considering and selecting useful EoFL LIBs and to determine key performance indicators (KPIs) to minimize economic risks for a successful second‐life market launch. KPIs were rated according to importance using a Likert scale, and reference values were introduced. A mixed‐methods approach, using expert interviews, an exploratory workshop, and an online survey, was applied. Twelve important preconditions were identified, with the “availability of information on battery specification” and “compliance with standards and regulations” considered very important. In addition, 12 KPIs were derived, covering six economic, three environmental, and three technical and safety‐related indicators. The KPIs “state of safety (SoS)” and “resource savings (Rsav)” were rated as highly important. Overall, the findings provide performance measurement guidance for repurposing companies, facilitating the market launch and adoption of second‐life applications. Future research can build on these results and investigate variations among different battery types, ultimately promoting a circular economy.
KW - Lithium-Ion battery
KW - Key performance indicators
KW - Circular economy
KW - Electric vehicle
KW - Sustainability
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-619167
DO - https://doi.org/10.1155/er/8331870
SP - 1
EP - 19
PB - Wiley
AN - OPUS4-61916
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prenner, Stefanie
A1 - Part, Florian
A1 - Jung-Waclik, Sabine
A1 - Bordes, Arnaud
A1 - Leonhardt, Robert
A1 - Jandric, Aleksander
A1 - Schmidt, Anita
A1 - Huber-Humer, Marion
T1 - Barriers and framework conditions for the market entry of second-life lithium-ion batteries from electric vehicles
N2 - Transition to circular economy for lithium-ion batteries used in electric vehicles requires integrating multiple stages of the value cycle. However, strategies aimed at extending the lifetime of batteries are not yet sufficiently considered within the European battery industry, particularly regarding repurposing. Using second-life lithium-ion batteries (SLBs) before subsequent recycling can offer several advantages, such as the development of sustainable business models, the reduction of emissions, and alignment with UN Sustainable Development Goals 7, 12, and 13. Using expert and problem-centred interviews along with an exploratory workshop, this study guides stakeholders in the battery sector by illustrating the necessary changes for a more holistic circular economy. Moreover, an extended political, economic, social, technological, environmental, legal, and additionally safety-related (PESSTEL) analysis approach is carried out, which has not yet been used in this context. In this process, barriers, as well as necessary institutional framework conditions and organisational requirements for a successful market entry of SLB applications are investigated. Among others, key barriers relate to the competition with first-life applications and safety concerns. SLBs require high manual labour costs for repurposing, along with expenses for expired warranties and re-certifications. Ownership structures in traditional business models often result in SLBs and their corresponding usage data staying under the control of the manufacturers. Market viability, however, requires a level playing field for both first-life and second-life operators as well as circular battery and data-sharing business models. Gathering data on the ageing performance and performing improved safety testing according to test protocols facilitates the reliable assessment of SLBs.
KW - Electric vehicle
KW - Circular economy
KW - Market entry barrier
KW - Repurposing
KW - Second-life lithium-ion battery
KW - Second-life battery energy storage system
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614543
DO - https://doi.org/10.1016/j.heliyon.2024.e37423
VL - 10
IS - 18
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-61454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müllner, S.
A1 - Held, T.
A1 - Tichter, Tim
A1 - Rank, P.
A1 - Leykam, D.
A1 - Jiang, W.
A1 - Lunkenbein, T.
A1 - Gerdes, T.
A1 - Roth, C.
T1 - Impact of Functional Groups in Reduced Graphene Oxide Matrices for High Energy Anodes in Lithium-Ion Batteries
N2 - Most high capacity anode materials for lithium-ion batteries (LiB) require a carbonaceous matrix. In this context one promising material is reduced graphene oxide (rGO). Herein, we present the influence of different reduction degrees of rGO on its physico-chemical properties, such as crystallinity, specific surface area, electrical conductivity and electrochemical lithiation/delithiation behavior. It is found that a heat treatment under inert and reducing atmospheres increases the long-range order of rGO up to a temperature of 700 °C. At temperatures around 1000 °C, the crystallinity decreases. With decreasing oxygen content, a linear decrease in irreversible capacity during cycle 1 can be observed, along with a significant increase in electrical conductivity. This decrease in irreversible capacity can be observed despite an increase in specific surface area indicating the more significant influence of the oxygen content on the capacity loss. Consequently, the reversible capacity increases continuously up to a carbon content of 84.4 at% due to the thermal reduction. Contrary to expectations, the capacity decreases with further reduction. This can be explained by the loss of functional groups that will be lithiated reversibly, and a simultaneous reduction of long-range order, as concluded from dq/dU analysis in combination with XRD analysis.
KW - Batteries
KW - Functional Materials
KW - Graphene Oxide
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606852
DO - https://doi.org/10.1149/1945-7111/ace70a
SN - 0013-4651
VL - 170
IS - 7
SP - 1
EP - 12
PB - The Electrochemical Society
AN - OPUS4-60685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Caianiello, Carlo
A1 - Tichter, Tim
A1 - Arenas, Luis F.
A1 - Wilhelm, René
T1 - Toward Symmetric Organic Aqueous Flow Batteries: Triarylamine‐Based Bipolar Molecules and Their Characterization via an Extended Koutecký–Levich Analysis
N2 - Symmetric organic flow batteries (SOFBs) can potentially address membrane crossover problems by employing bipolar redox‐active organic molecules (BROMs). Herein, a triarylamine (TAA) skeleton was chosen as a posolyte moiety for a new class of bipolar molecules for pH‐neutral aqueous flow batteries (FBs). Pyridinium and viologen derivatives were tethered to the posolyte moiety, and the new compounds were characterized. Cyclic voltammetry revealed that only viologen with a highly hydrophilic substituent, connected to the TAA moiety via a Zincke reaction, could be reversibly reduced. Varying the supporting electrolyte concentration on the selected derivative revealed water solubility as a challenge for further development. The selected derivative, MeO‐TPA‐Vi‐DMAE, was subjected to hydrodynamic voltammetry, and a modified Koutecký–Levich analysis was developed to investigate the observed potential‐dependent currents at the hydrodynamically dominated region, which are often seen with redox‐active organic molecules. This model discarded a purely Ohmic effect, showing a useful Levich slope at a certain overpotential before the onset of a secondary reaction. TAA‐based BROMs hold promise for pH‐neutral aqueous SOFBs, and the results will guide the design of new derivatives. The three‐term Koutecký–Levich relation here introduced will be useful not only to develop BROM‐based FBs but will most likely appeal to a much broader audience.
KW - Redox Flow Batteries
KW - Koutecký-Levich Analysis
KW - Rotating Disc Electrode
KW - Redox-active Bipolar Molecules
KW - Electrode Kinetics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631476
DO - https://doi.org/10.1002/chem.202500815
SN - 1521-3765
SP - 1
EP - 15
PB - Wiley VHC-Verlag
AN - OPUS4-63147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Christensen, J.
A1 - Thomas, P.
A1 - Failleau, G.
A1 - Eisermann, R.
A1 - Hicke, Konstantin
A1 - Krenek, S.
T1 - Fiber artefact for performance evaluation of time domain distributed fiber sensor interrogators
N2 - Distributed fiber sensing (DFS) is a powerful tool for structural health monitoring (SHM), allowing continuous and seamless measurements of temperature and strain along the fiber. The spatial accuracy of a DFS interrogator, as a key parameter of the system, is vital for precisely locating structural perturbations or defects. Its evaluation and calibration methods however attract little attention. A fiber optic artefact based on a fiber loop is developed to evaluate distance accuracy and signal quality for both self-developed and commercial sensing systems based on Rayleigh, Raman, and Brillouin scattering effects, respectively. The measured distance is corrected to remove the influence of the pulse width. Additionally, the obtained SNRs are compared for different loop trips and pulse widths, assisting to assess signal quality for SHM applications.
KW - Structural health monitoring
KW - Distributed fiber sensing
KW - Distributed temperature sensing
KW - Fiber artefact
KW - Spatial correction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648966
DO - https://doi.org/10.1088/1361-6501/ae214e
VL - 36
IS - 11
SP - 1
EP - 10
PB - IOP Publishing Ltd
CY - Bristol, UK
AN - OPUS4-64896
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kleinbub, Sherin
A1 - Braymer, Joseph J
A1 - Pfeiffer, Friedhelm
A1 - Dyall-Smith, Mike
A1 - Spirgath, Kristin
A1 - Alfaro-Espinoza, Gabriela
A1 - Koerdt, Andrea
T1 - From Genes to Black Rust: Genomic insights into corrosive methanogens
N2 - Within the past ten years, genetic evidence has been increasing for the direct role that microbes play in microbiologically influenced corrosion (MIC), also known as biocorrosion or biodeterioration. One prominent example is the correlation between the corrosion of metal and the presence of genes encoding an extracellular [NiFe]-hydrogenase (MIC hydrogenase) in the methanogenic archaeon, Methanococcus maripaludis. In this study, DNA sequencing and bioinformatic analysis were used to classify the MIC hydrogenase as belonging to a core set of genes, the MIC core, found so far in Methanococci and Methanobacteria classes of methanogens. Genetic evidence is provided for the mobilization of the MIC core via multiple mechanisms, including a horizontal gene transfer event from Methanobacteria to Methanococci and a newly described MIC-transposon. A detailed comparison of M. maripaludis genomes further pointed to the relevance that cell wall modifications involving N-glycosylation of S-layer proteins and the MIC hydrogenase likely play in methanogen-induced MIC (Mi-MIC). Microscopic analysis of corrosive methanogens encoding the MIC core indicated that Methanobacterium-affiliated strain IM1 can form extensive biofilms on the surface of corrosion products whereas individual cells of M. maripaludis Mic1c10 were only found localized to crevices in the corrosion layer. An updated model of Mi-MIC involving two modes of action is presented, which predicts that the propensity of cells to adhere to iron surfaces directly influences the rate of corrosion due to the localization of the MIC hydrogenase at the metal-microbe interface.
KW - Biocorrosion
KW - Hydrogenases
KW - Metalloprotein
KW - Microbes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649425
DO - https://doi.org/10.1093/femsmc/xtaf018
SN - 2633-6685
VL - 6
SP - 1
EP - 19
PB - Oxford University Press (OUP)
AN - OPUS4-64942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Lange, D.
A1 - Hahn, Oliver
ED - Martin, E.
ED - Brox, T.
ED - Lange, D.
T1 - Materials and materiality as keys to understanding a map of Mount Kailash
N2 - While graphic and linguistic content is central to the identification of maps and can provide insights into the concepts and systems of rules, ideas and beliefs that led to their production, the materials that constitute maps may speak about manufacturing processes, the provenance of raw materials, the practical and technical knowledge of the mapmakers, and the use of the maps. This contribution underscores how the materials employed in Tibetan maps reveal aspects of their context and trajectory. Furthermore, materiality, conceptualized as a convergence of matter and imagination, can yield even more profound insights into artefacts like maps. Through a detailed case study of a map of Mount Kailash in the tangkha format and a specialized material-scientific analysis of the colourants employed in its creation, this contribution explores how a map can ‘talk’ through its materiality. With this case study it will show how Tibetan Studies can benefit from interdisciplinary collaboration. Crossing the field’s traditional boundaries and working with other disciplines, we argue, is absolutely essential for serious research.
KW - Archaeometry
KW - Non-destructive analysis
KW - Cultural heritage
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648625
SN - 978-3-98887-016-2
DO - https://doi.org/10.11588/hasp.1522
SP - 147
EP - 176
PB - Heidelberg Asian Studies Publishing (HASP)
CY - Heidelberg
AN - OPUS4-64862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tichter, Tim
A1 - Tichter, Alex
A1 - Andrae, Dirk
A1 - Roth, Christina
T1 - Simulating cyclic voltammetry at rough electrodes by the digital-simulation–deconvolution–convolution algorithm
N2 - The influence of electrode roughness on diffusional cyclic voltammetry (CV) is investigated from a theoretical perspective. For this purpose, the digital-simulation–deconvolution–convolution (DSDC) algorithm, initially developed for the simulation of CV at porous electrodes, is subjected to three substantial modifications. First, by employing adaptive numerical resolution and sample volumina, the computational demand of the digital simulation (DS) step is reduced significantly. Second, by modifying the Douglas–Gunn algorithm of the DS-step to operate on an arbitrarily incremented spatial grid perpendicular to the macroscopically planar electrode surface, the bulk of the fluid can be treated with an exponentially increasing spatial discretization which uses computational power even more efficiently. The third modification is an optimization of the computationally demanding deconvolution step which is used to extract the mass-transfer function from the data computed in the DS-step. This, initially recursive procedure, is replaced by a three-step sequence consisting of (I) a numerical Laplace transformation (NLT) on an exponentially expanding time-grid, (II) a Laplace-domain integration (LDI) and finally (III) a numerical inversion of Laplace transformation (NILT) using the Gaver–Stehfest (GS) inversion formula. Based on this novel strategy for CV simulation, the effects of electrode roughness are thoroughly investigated. It is demonstrated that for an ideally reversible reaction the effects of electrode roughness on the CV response are insignificant at common experimental timescales. In contrast, for scenarios with electrochemically quasi-reversible (or irreversible) kinetics, the apparent rate constants are allegedly upscaled by the area ratio 𝜓 = 𝐴rough∕𝐴planar . This manifests in a lower peak-to-peak separation without a distortion of the shape of the voltammetric profile. This behavior is finally explained in a quantitative manner in terms of convolution-sums and mass-transfer functions which ultimately puts the parameter electrode roughness into the semianalytical framework of convolutive modeling.
KW - Rough electrodes
KW - Electrode kinetics and Peak-to-Peak separation
KW - Vanadium redox-flow batteries
KW - Convolutive modeling
KW - Digital-simulation
KW - Numerical inversion of Laplace transformation
KW - Gaver–Stehfest inversion formula
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614620
DO - https://doi.org/10.1016/j.electacta.2024.145175
VL - 508
SP - 1
EP - 17
PB - Elsevier B.V.
AN - OPUS4-61462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seuthe, T.
A1 - Mermillod-Blondin, A.
A1 - Grehn, M.
A1 - Bonse, Jörn
A1 - Wondraczek, L.
A1 - Eberstein, M.
T1 - Structural relaxation phenomena in silicate glasses modifed by irradiation with femtosecond laser pulses
N2 - Structural relaxation phenomena in binary and multicomponent lithium silicate glasses were studied upon irradiation with femtosecond (fs) laser pulses (800 nm central wavelength, 130 fs pulse duration) and subsequent thermal annealing experiments. Depending on the annealing temperature, micro-Raman spectroscopy analyses evidenced different relaxation behaviours, associated to bridging and non-bridging oxygen structures present in the glass network. The results indicate that the mobility of lithium ions is an important factor during the glass modification with fs-laser pulses. Quantitative phase contrast imaging (spatial light interference microscopy) revealed that these fs-laser induced structural modifications are closely related to local changes in the refractive index of the material. The results establish a promising strategy for tailoring fs-laser sensitivity of glasses through structural mobility.
KW - Femtosecond laser
KW - Silicate glasses
KW - Raman spectroscopy
KW - Structural relaxation
KW - Refractive index
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393045
DO - https://doi.org/10.1038/srep43815
SN - 2045-2322
VL - 7
SP - 43815, 1
EP - 43815, 10
PB - Nature Publishing Group
CY - London, UK
AN - OPUS4-39304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mull, Birte
A1 - Möhlmann, L.
A1 - Wilke, Olaf
T1 - Photocatalytic degradation of toluene, butyl acetate and limonene under UV and visible light with titanium dioxide-graphene oxide as photocatalyst
N2 - Photocatalysis is a promising technique to reduce volatile organic compounds indoors. Titanium dioxide (TiO2) is a frequently-used UV active photocatalyst. Because of the lack of UV light indoors, TiO2 has to be modified to get its working range shifted into the visible light spectrum. In this study, the photocatalytic degradation of toluene, butyl acetate and limonene was investigated under UV LED light and blue LED light in emission test chambers with catalysts either made of pure TiO2 or TiO2 modified with graphene oxide (GO). TiO2 coated with different GO amounts (0.75%–14%) were investigated to find an optimum ratio for the photocatalytic degradation of VOC in real indoor air concentrations. Most experiments were performed at a relative humidity of 0% in 20 L emission test chambers. Experiments at 40% relative humidity were done in a 1 m³ emission test chamber to determine potential byproducts. Degradation under UV LED light could be achieved for all three compounds with almost all tested catalyst samples up to more than 95%. Limonene had the highest degradation of the three selected volatile organic compounds under blue LED light with all investigated catalyst samples.
KW - Photocatalysis
KW - Emission test chamber
KW - Volatile organic compound
KW - VOC
KW - Degradation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402955
DO - https://doi.org/10.3390/environments4010009
SN - 2076-3298
VL - 4
IS - 1
SP - Article 9, 1
EP - 9
PB - MDPI
CY - Basel
AN - OPUS4-40295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Natsopoulou, M. E.
A1 - McMahon, Dino Peter
A1 - Doublet, V.
A1 - Frey, E.
A1 - Rosenkranz, P.
A1 - Paxton, R. J.
T1 - The virulent, emerging genotype B of Deformed wing virus is closely linked to overwinter honeybee worker loss
N2 - Bees are considered to be threatened globally, with severe overwinter losses of the most important commercial pollinator, the Western honeybee, a major concern in the Northern Hemisphere. Emerging infectious diseases have risen to prominence due to their temporal correlation with colony losses. Among these is Deformed wing virus (DWV), which has been frequently linked to colony mortality. We now provide evidence of a strong statistical association between overwintering colony decline in the field and the presence of DWV genotype-B (DWV-B), a genetic variant of DWV that has recently been shown to be more virulent than the original DWV genotype-A. We link the prevalence of DWV-B directly to a quantitative measure of overwinter decline (workforce mortality) of honeybee colonies in the field. We demonstrate that increased prevalence of virus infection in individual bees is associated with higher overwinter mortality. We also observed a substantial reduction of infected colonies in the spring, suggesting that virus-infected individuals had died during the winter. Our findings demonstrate that DWV-B, plus possible A/B recombinants exhibiting DWV-B at PCR primer binding sites, may be a major cause of elevated overwinter honeybee loss. Its potential emergence in naïve populations of bees may have far-reaching ecological and economic impacts.
KW - Honeybee
KW - Loss
KW - Virulence
KW - Virus
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410446
DO - https://doi.org/10.1038/s41598-017-05596-3
SN - 2045-2322
IS - 7
SP - 5242, 1
EP - 5242, 9
AN - OPUS4-41044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pohl, Rainer
A1 - Commandeur, C.
A1 - Erthner, Thomas
A1 - Kreutzbruck, M.
A1 - Pelkner, Matthias
T1 - GMR-Streufluss-Prüfsystem zur Detektion verdeckter Fehler in Feinblechen
N2 - BAM und TATA Steel untersuchen gemeinsam, ob sich die Prüfung von ferritischen Feinblechen mit einer Stärke von etwa 0,2 mm während der Fertigung durch den Einsatz von GMR-Sensorik verbessern lässt. Hierzu wurde eine Vorstudie an Feinblechen mit eingebrachten Mikronuten durchgeführt. Diese Nuten variieren in ihrer Tiefe zwischen 5 μm und 60 μm und wurden verdeckt mit ZfP-angepassten GMR-Sensorarrays geprüft. Die Ergebnisse der Vorstudie zeigten, dass bei verdeckter Prüfung schon kleinste Defekte mit einer Tiefe von 10 μm - gleichbedeutend mit einer Restwanddicke von 90 % – mit einem SNR > 6 dB detektiert werden konnten, wobei der Abstand der Prüfsonde zur Oberfläche bis zu 500 μm betrug. Zudem wurden in der Vorstudie Untersuchungen zur Prüfgeschwindigkeit und Praxistauglichkeit durchgeführt.
Basierend auf den hier gewonnenen Ergebnissen wird ein erster Demonstrator für eine zuverlässige Prüfung eines Teilbereiches von 50 mm des Feinbleches innerhalb einer Produktionslinie aufgebaut. Zum Einsatz kommen Prüfsonden mit jeweils 24 GMR-Sensorelementen. Hierbei wird das Ziel einer umfassenden Prüfung des Feinblechs über die gesamte Breite von 1200 mm angestrebt. Eine besondere Herausforderung stellt dabei die hohe Anzahl von mehr als 1000 Sensorelementen dar. Das hierfür entwickelte Prüfkonzept umfasst neben einer angepassten Erzeugung des Magnetfeldes die Entwicklung einer geeigneten schnellen und sicheren Elektronik für die neuen Mehrkanalprüfköpfe. Neben der Vorstellung des Prüfkonzeptes und seiner Eigenschaften vergleichen wir die erzielten Prüfergebnisse an verschiedenen Vergleichsfehlern mit denen der Vorstudie.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Streuflussprüfung
KW - GMR
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343354
UR - https://jt2015.dgzfp.de/Portals/jt2015/BB/mi2b3.pdf
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-34335
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavlovic, Mato
A1 - Zoëga, Andreas
A1 - Kurz, J. H.
A1 - Zanotelli, Christina
T1 - Investigations to introduce the probability of detection method for ultrasonic inspection of hollow axles at Deutsche Bahn
N2 - The vast experience with the automated, ultrasonic system for the inspection of hollow railway axles used by Deutsche Bahn shows that much smaller flaws are detectable than required. This results in a number of false calls. False calls lead to unnecessary demounting and disassembling of wheelsets, which generates unnecessary additional costs. In order to adjust the sensitivity of the inspection system to reduce the number of false calls without compromising safety, the capability of the system to detect cracks needs to be comprehensively established. This capability can be quantified by using probability of detection (POD) curves for the system. The multi-parameter POD model makes it possible to include several factors that influence the crack detection in the analysis. The analysis presented in this paper shows that crack position, orientation, depth extension, and shape as well as the geometry of the axle all have influence on the ultrasonic response amplitude. For future work, calculation of the POD using multi-parameter POD model with these parameters is planned.
T2 - ESIS TC24 Workshop "Integrity of Railway Structures"
CY - Leoben, Austria
DA - 24.10.2016
KW - Crack
KW - Reliability
KW - POD
KW - Axle
KW - Ultrasonic
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-415201
DO - https://doi.org/10.1016/j.prostr.2017.07.002
SN - 2452-3216
VL - 4
SP - 79
EP - 86
PB - Elsevier, B.V.
AN - OPUS4-41520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Doublet, V.
A1 - Poeschl, Y.
A1 - Gogol-Döring, A.
A1 - Alaux, C.
A1 - Annoscia, D.
A1 - Aurori, C.
A1 - Barribeau, S. M.
A1 - Bedoya-Reina, O. C.
A1 - Brown, M. J. F.
A1 - Bull, J. C.
A1 - Flenniken, M. L.
A1 - Galbraith, D. A.
A1 - Genersch, E.
A1 - Gisder, S.
A1 - Grosse, I.
A1 - Holt, H. L.
A1 - Hultmark, D.
A1 - Lattorff, H. M. G.
A1 - Le Conte, Y.
A1 - Manfredini, F.
A1 - McMahon, Dino Peter
A1 - Moritz, R. F. A.
A1 - Nazzi, F.
A1 - Niño, E. L.
A1 - Nowick, K.
A1 - Van Rij, R. P.
A1 - Paxton, R. J.
A1 - Grozinger, C. M.
T1 - Unity in defence: honeybee workers exhibit conserved molecular responses to diverse pathogens
N2 - Background: Organisms typically face infection by diverse pathogens, and hosts are thought to have developed specific responses to each type of pathogen they encounter. The advent of transcriptomics now makes it possible to test this hypothesis and compare host gene expression responses to multiple pathogens at a genome-wide scale. Here, we performed a meta-analysis of multiple published and new transcriptomes using a newly developed bioinformatics approach that filters genes based on their expression profile across datasets. Thereby, we identified common and unique molecular responses of a model host species, the honey bee (Apis mellifera), to its major pathogens and parasites: the Microsporidia Nosema apis and Nosema ceranae, RNA viruses, and the ectoparasitic mite Varroa destructor, which transmits viruses.
Results: We identified a common suite of genes and conserved molecular pathways that respond to all investigated pathogens, a result that suggests a commonality in response mechanisms to diverse pathogens. We found that genes differentially expressed after infection exhibit a higher evolutionary rate than non-differentially expressed genes. Using our new bioinformatics approach, we unveiled additional pathogen-specific responses of honey bees; we found that apoptosis appeared to be an important response following microsporidian infection, while genes from the immune signalling pathways, Toll and Imd, were differentially expressed after Varroa/virus infection. Finally, we applied our bioinformatics approach and generated a gene co-expression network to identify highly connected (hub) genes that may represent important mediators and regulators of anti-pathogen responses.
Conclusions: Our meta-analysis generated a comprehensive overview of the host metabolic and other biological processes that mediate interactions between insects and their pathogens. We identified key host genes and pathways that respond to phylogenetically diverse pathogens, representing an important source for future functional studies as well as offering new routes to identify or generate pathogen resilient honey bee stocks. The statistical and bioinformatics approaches that were developed for this study are broadly applicable to synthesize information across transcriptomic datasets. These approaches will likely have utility in addressing a variety of biological questions.
KW - Coexpression
KW - Apis mellifera
KW - Nosema
KW - Varroa destructor
KW - DWV
KW - IAPV
KW - RNA virus
KW - Meta-analysis
KW - Transcriptomics
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410439
DO - https://doi.org/10.1186/s12864-017-3597-6
SN - 1471-2164
VL - 18
SP - 207
EP - 224
AN - OPUS4-41043
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bandow, Nicole
A1 - Simon, Franz-Georg
T1 - Significance of cadmium from artists' paints to agricultural soils and the food chain
N2 - Background: An Annex XV restriction dossier for cadmium in artists’ paints was submitted by an EU member state to the European Chemicals Agency ECHA. By cleaning used brushes under the tap cadmium can enter the food chain via waste water treatment and subsequent agricultural application of the sewage sludge. It was estimated that 110 kg Cd per year is spread on agricultural land via this exposure route. Other sources of Cd amount to almost 120 tons per year.
Results: The mobility of Cd from pigments was studied in a field-like scenario by leaching experiments using soil samples amended with sewage sludge and spiked with Cd pigments in percolation columns. The redox conditions were confirmed to be the decisive factor for the release of Cd. The release of Cd from artists’ paints was in most cases 1% or lower in the experiments performed.
Conclusions: Application of sewage sludge containing Cd from artist paints does not increase the amount of Cd leached from this soils. Furthermore the quantity of Cd from artists’ paints calculated in the restriction dossier is negligible compared to other sources of Cd to agricultural soil. Therefore ECHA did not consider the proposed restriction to be the most appropriate EU wide measure to address the negligible level of risk.
KW - REACH regulation
KW - Sewage sludge
KW - Fertilizer
KW - Leaching test
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358261
DO - https://doi.org/10.1186/s12302-016-0077-6
SN - 2190-4715
VL - 28
IS - 12
SP - 1
EP - 10
AN - OPUS4-35826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tamschick, S.
A1 - Rozenblut-Kościsty, B.
A1 - Ogielska, M.
A1 - Lehmann, Andreas
A1 - Lymberakis, P.
A1 - Hoffmann, F.
A1 - Lutz, I.
A1 - Kloas, W.
A1 - Stöck, M.
T1 - Sex reversal assessments reveal different vulnerability to endocrine disruption between deeply diverged anuran lineages
N2 - Multiple anthropogenic stressors cause worldwide amphibian declines. Among several poorly investigated causes is global pollution of aquatic ecosystems with endocrine disrupting compounds (EDCs). These substances interfere with the endocrine system and can affect the sexual development of vertebrates including amphibians. We test the susceptibility to an environmentally relevant contraceptive, the artificial estrogen 17α-ethinylestradiol (EE2), simultaneously in three deeply divergent systematic anuran families, a model-species, Xenopus laevis (Pipidae), and two non-models, Hyla arborea (Hylidae) and Bufo viridis (Bufonidae). Our new approach combines synchronized tadpole exposure to three EE2-concentrations (50, 500, 5,000 ng/L) in a flow-through-system and pioneers genetic and histological sexing of metamorphs in non-model anurans for EDC-studies. This novel methodology reveals striking quantitative differences in genetic-male-to-phenotypic-female sex reversal in non-model vs. model species. Our findings qualify molecular sexing in EDC-analyses as requirement to identify sex reversals and state-of-the-art approaches as mandatory to detect speciesspecific vulnerabilities to EDCs in amphibians.
KW - Endocrine disruption
KW - 17α-ethinylestradiol (EE2)
KW - Mass spectrometry
KW - Sex reversal
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357797
DO - https://doi.org/10.1038/srep23825
SN - 2045-2322
VL - 6
SP - Article No. 23825, 1
EP - 8
PB - Nature publishing group
AN - OPUS4-35779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Swaraj, S.
A1 - Dietrich, Paul
A1 - Unger, Wolfgang
T1 - Simultaneous surface and bulk sensitive XAS measurements of magnetic particle clusters
N2 - Magnetic iron oxide nanoparticle clusters (mnpc) coated with organic stabilizers were investigated using scanning transmission x-ray microscopy (STXM). Simultaneous surface and bulk sensitive Fe L₃ edge absorption spectra, obtained using a photomultiplier tube and a channeltron, were used to detect subtle changes in the oxidation state in the surface and bulk of Iron Oxide mnpc. The effectiveness of this mode of STXM operation is demonstrated for these nanoparticle clusters.
T2 - X-Ray Microscopy Conference 2016 (XRM 2016)
CY - Oxford, UK
DA - 15.08. 2016
KW - Fe L3 edge absorption spectra
KW - Scanning transmission x- ray microscopy
KW - Magnetic iron oxide nanoparticle clusters
KW - XAS
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410576
UR - http://iopscience.iop.org/article/10.1088/1742-6596/849/1/012014/pdf
DO - https://doi.org/10.1088/1742-6596/849/1/012014
SN - 1742-6588
VL - 849
SP - 012014, 1
EP - 012014, 5
PB - IOP Publishing
AN - OPUS4-41057
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tuma, Dirk
A1 - Kumbhar, V. S.
A1 - Lee, Y. R.
A1 - Ra, C. S.
A1 - Min, B.-K.
A1 - Shim, J.-J.
T1 - Modified chemical synthesis of MnS nanoclusters on nickel foam for high performance all-solid-state asymmetric supercapacitors
N2 - Novel MnS nanoclusters were synthesized on nickel foam (NF) using a successive ionic layer adsorption and reaction (SILAR) method. MnS nanoclusters with different sizes were obtained by varying the number of deposition cycles. The crystal structure, chemical composition, and surface microstructure of the electrodes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field Emission scanning electron microscopy, and high-resolution transmission electron microscopy. The electrochemical behavior of the MnS nanoclusters was examined by cyclic voltammetry, galvanostatic charge–discharge, cycling test, and electrochemical impedance spectroscopy. The MnS nanoclusters prepared with 90 SILAR cycles showed the best supercapacitance in a 6 M KOH aqueous electrolyte with a specific capacitance of 828 F/g at a scan rate of 5 mV/s and cycling stability of 85.2 % after 5000 charge–discharge cycles.
Moreover, an asymmetric supercapacitor (ASC) was assembled with the as-prepared MnS electrode on NF as the positive electrode, hydrothermally prepared reduced graphene oxide (rGO) on NF as the negative electrode, and PVA–KOH gel as the electrolyte. The MnS@NF//rGO@NF ASC showed excellent electrochemical performance with maximum energy and power densities of 34.1 Wh/kg and 12.8 kW/kg, respectively. The ASC also showed a capacitive retention of 86.5 % after 2000 charge–discharge cycles, highlighting its practical application for energy storage.
KW - Nanocluster
KW - Electrochemical behavior
KW - Asymmetric supercapacitor
KW - Graphene oxide
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403147
DO - https://doi.org/10.1039/c7ra00772h
SN - 2046-2069
VL - 7
IS - 27
SP - 16348
EP - 16359
PB - The Royal Society of Chemistry
CY - London
AN - OPUS4-40314
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Griesche, Axel
A1 - Dabah, Eitan
A1 - Kannengießer, Thomas
A1 - Hilger, A.
A1 - Kardjilov, N.
A1 - Manke, I.
A1 - Schillinger, B.
T1 - Measuring hydrogen distributions in iron and steel using neutrons
N2 - Neutron tomography has been applied to investigate the mechanism of hydrogen assisted cracking in technical iron and supermartensitic steel. Rectangular technical iron block samples showed blistering due to intense hydrogen charging and the tomographic method revealed in situ the spatial distribution of hydrogen and cracks. Hydrogen accumulated in a small region around cracks and the cracks are filled with hydrogen gas. Cracks close to the surface contained no hydrogen. Hydrogenous tensile test samples of supermartensitic steel were pulled until rupture and showed hydrogen accumulations at the notch base and in the plastically deformed region around the fracture surface.
T2 - 10th World Conference on Neutron Radiography (WCNR)
CY - Grindelwald, Switzerland
DA - 05.10.2014
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-348022
DO - https://doi.org/10.1016/j.phpro.2015.07.062
SN - 1875-3892
VL - 69
SP - 445
EP - 450
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-34802
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karabeliov, Krassimire
A1 - Baeßler, Matthias
A1 - Cuéllar, Pablo
A1 - Rücker, Werner
T1 - A method for system identification of a structure supported by nonlinear springs using evolutionary computing
N2 - A mechanical structure supported by nonlinear springs subjected to an external load is considered. If all mechanical parameters of the system were known, the displacement of the system subjected to this load could be easily calculated. If not all of the parameters are known, but the load and the displacement are measured at one location, an inverse problem exists. In the presented problem the nonlinear springs are unknown and have to be determined. At first glance a problem needs to be solved, which is underdetermined due to the number of unknown variables. However, evolutionary computing can be applied to solve this inverse, nonlinear and multimodal problem. Sometimes a prior knowledge exists on certain system properties, which is difficult to implement into analytical or numerical solver. This knowledge can play a decisive role in identifying the system properties and it can be easily included as boundary condition when applying evolutionary algorithm. This article examines how and under what conditions the spring resistances can be identified. The procedure is exemplified at a mechanical system of a pile foundation.
T2 - 2nd International conference on mathematical modeling in physical sciences 2013
CY - Prague, Czech Republic
DA - 01.09.2013
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304531
UR - http://iopscience.iop.org/1742-6596/490/1/012095/pdf/1742-6596_490_1_012095.pdf
DO - https://doi.org/10.1088/1742-6596/490/1/012095
SN - 1742-6588
SN - 1742-6596
VL - 490
IS - 012095
SP - 1
EP - 4
PB - IOP Publ.
CY - Bristol, UK
AN - OPUS4-30453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naka, A.
A1 - Yasutaka, T.
A1 - Sakanakura, H.
A1 - Kalbe, Ute
A1 - Watanabe, Y.
A1 - Inoba, S.
A1 - Takeo, M.
A1 - Inui, T.
A1 - Katsumi, T.
A1 - Fujikawa, T.
A1 - Sato, K.
A1 - Higashinog, K.
A1 - Someyaga, M.
T1 - Column percolation test for contaminated soils: Key factors for standardization
N2 - Column percolation tests may be suitable for prediction of chemical leaching from soil and soil materials. However, compared with batch leaching tests, they are time-consuming. It is therefore important to investigate ways to shorten the tests without affecting the quality of results. In this study, we evaluate the feasibility of decreasing testing time by increasing flow rate and decreasing equilibration time compared to the conditions specified in ISO/TS 21268-3, with equilibration periods of 48 h and flow rate of 12 mL/h. We tested three equilibration periods (0, 12–16, and 48 h) and two flow rates (12 and 36 mL/h)on four different soils and compared the inorganic constituent releases. For soils A and D, we observed similar values for all conditions except for the 0 h–36 mL/h case. For soil B, we observed no appreciable differences between the tested conditions, while for soil C there were no consistent trends probably due to the difference in ongoing oxidation reactions between soil samples. These results suggest that column percolation tests can be shortened from 20 to 30 days to 7–9 days by decreasing the equilibration time to 12–16 h and increasing the flow rate to 36 mL/h for inorganic substances.
KW - Contaminated soils
KW - Column percolation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372038
DO - https://doi.org/10.1016/j.jhazmat.2016.08.046
SN - 0304-3894
VL - 320
SP - 326
EP - 340
PB - Elsevier B.V.
AN - OPUS4-37203
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - In-situ-phase analysis using synchrotron radiation of low transformation temperature (LTT) welding material
N2 - Cold cracking resistance is a relevant evaluation criterion for welded joints and affected by residual stresses which result from the welding procedure. Compressive residual stresses can thereby have a positive influence on preventing cracking. A unique possibility of generating compressive residual stresses already during the welding procedure is offered by the so-called Low Transformation Temperature (LTT) filler wires. Compared to conventional wires, these materials show decreased phase transformation temperatures which can work against the cooling-specific contraction. In consequence, distinct compressive residual stresses can be observed within the weld and adjacent areas. The strength of these fillers makes them potentially applicable to high-strength steel welding. Investigations were carried out to determine the phase transformation behaviour of different LTT-filler materials. Transformation temperatures were identified using Single Sensor Differential Thermal Analysis (SS-DTA). Additionally Synchrotron radiation was used to measure the transformation kinetics of all involved crystalline phases during heating and cooling of a simulated weld thermal cycle.
KW - In-situ phase analysis
KW - Energy dispersive diffraction
KW - Phase transformation
KW - Low Transformation Temperature filler wire
PY - 2009
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-205922
DO - https://doi.org/10.1590/S0104-92242009000100010
SN - 0104-9224
SN - 1980-6973
VL - 14
IS - 1
SP - 82
EP - 88
PB - Associação Brasileira de Soldagem, ABS
CY - Rio de Janeiro
AN - OPUS4-20592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maul, Ronald
A1 - Greer, B.
A1 - Campbell, K.
A1 - Elliott, C.T.
T1 - Detection of freshwater cyanotoxins and measurement of masked microcystins in tilapia from Southeast Asian aquaculture farms
N2 - Recently, there has been a rise in freshwater harmful algal blooms (HABs) globally, as well as increasing aquaculture practices. HABs can produce cyanotoxins, many of which are hepatotoxins. An ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for nine cyanotoxins across three classes including six microcystins, nodularin, cylindrospermopsin and anatoxin-a. The method was used to analyse free cyanotoxin(s) in muscle (n = 34), liver (n = 17) and egg (n = 9) tissue samples of 34 fish sourced from aquaculture farms in Southeast Asia. Conjugated microcystin was analysed by Lemieux oxidation to ascertain the total amount of microcystin present in muscle. Some tilapia accumulated free microcystin-LR in the muscle tissue at a mean of 15.45 μg/kg dry weight (dw), with total microcystin levels detected at a mean level of 110.1 μg/kg dw, indicating that the amount of conjugated or masked microcystin present in the fish muscle accounted for 85% of the total. Higher levels of cyanotoxin were detected in the livers, with approximately 60% of those tested being positive for microcystin-LR and microcystin-LF, along with cylindrospermopsin. Two fish from one of the aquaculture farms contained cylindrospermopsin in the eggs; the first time this has been reported. The estimated daily intake for free and total microcystins in fish muscle tissue was 2 and 14 times higher, respectively, than the tolerable daily intake value. This survey presents the requirement for further monitoring of cyanotoxins, including masked microcystins, in aquaculture farming in these regions and beyond, along with the implementation of guidelines to safeguard human health.
KW - Harmful algal bloom
KW - UPLC-MS/MS
KW - Bioaccumulation
KW - Human health
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404669
DO - https://doi.org/10.1007/s00216-017-0352-4
SN - 1618-2642
SN - 1618-2650
VL - 409
IS - 16
SP - 4057
EP - 4069
PB - Springer
CY - Heidelberg
AN - OPUS4-40466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech, Anja
A1 - Wilke, Olaf
A1 - Mull, Birte
A1 - Horn, Wolfgang
A1 - Jann, Oliver
T1 - Development of a TDS-GC-FID method for the determination of methanol and ethanol in air
N2 - A method for the determination of very volatile organic compounds (VVOC) in air was developed and successfully tested for methanol and ethanol. Carbotrap300® (a multi-bed tube using Carbopack C®, Carbopack B® and Carbosive SIII®) was selected as sorption material for thermal desorption and tested for its suitability for emission test chamber measurements. The adsorption behaviour and the chromatographic results are influenced negatively by spiking aqueous solutions on the adsorption medium for calibration purposes. The latter effect can be reduced by blowing dry air across the adsorbent to remove the adsorbed water. Detection and quantification limits were determined for a GC-FID system and compared to GC-MS. The applicability of the method was tested with a methanol eliminating silane modified polymeric adhesive (SMP-adhesive for parquet) in an emission test chamber
N2 - Eine Methode zur Bestimmung von sehr leicht flüchtigen Verbindungen in Luft wurde für Methanol und Ethanol entwickelt und erfolgreich getestet. Dafür wurde Carbotrap300® (Multibettrohr aus Carbopack C®, Carbopack B® und Carbosive SIII®) als Sorptionsmedium für die Thermodesorption ausgewählt und dessen Eignung für Emissionskammermessungen untersucht. Das Adsorptionsverhalten und die chromatographischen Ergebnisse werden negativ durch die Aufgabe von wässrigen Kalibrierlösungen auf das Adsorptionsmedium beeinflusst. Durch das Überleiten von trockener Luft kann dieser Effekt verringert werden, da so das adsorbierte Wasser entfernt wird. Die Nachweis- und Bestimmungsgrenzen wurden für ein eingesetztes GC- FID-System ermittelt und mit einem GC-MS verglichen. Mit einem methanolabspaltenden silanmodifizierten Polymerklebstoff (SMP-Parkettkleber), der in eine Emissionskammer eingebracht wurde, konnte die Tauglichkeit der Methode überprüft werden.
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-297020
UR - http://www.gefahrstoffe.de/gest/article.php?data[article_id]=76019
SN - 0949-8036
SN - 0039-0771
SN - 1436-4891
VL - 73
IS - 11/12
SP - 477
EP - 482
PB - Springer-VDI-Verlag
CY - Düsseldorf
AN - OPUS4-29702
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yasutaka, T.
A1 - Imoto, Y.
A1 - Kurosawa, A.
A1 - Someya, M.
A1 - Higashino, K.
A1 - Kalbe, Ute
A1 - Sakanakura, H.
T1 - Effects of colloidal particles on the results and reproducibility of batch leaching tests for heavy metal-contaminated soil
N2 - A simple batch test leaching procedure is used in many countries, as a compliance test, to evaluate the leaching of mainly inorganic substances from soil. However, agitating certain types of soil and then passing the solution through a membrane filter with 0.45-µm pores yields filtrates that have been colored by the colloidal particles. These colloids might affect the results of the inorganic substances obtained in the batch tests. In this study, we evaluated the effects of colloidal particles on the results and the reproducibility of batch tests on contaminated soil using different agitation methods and membrane filters with different pore sizes. The leaching behaviors of As, Pb, Se, F and Cl from three types of soil were studied. The As and Pb concentrations in the leachates of some types of soil were clearly affected by the amount of colloidal particles with a diameter of 0.10–0.45 µm and by the agitation method used. This was probably because As and Pb were present mainly in the particulate form in the leachate that had been passed through a membrane filter with 0.45-µm pores. This is not the case for every type of soil. The results of batch leaching tests showed that not only dissolved but also colloidal forms with a diameter of 0.10–0.45 µm might be included and that the existence of colloidal particles in the leachate decreases the batch leaching test reproducibility.
KW - Leaching
KW - Contaminated soil
KW - Heavy metals
KW - Colloids
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429940
UR - https://www.sciencedirect.com/science/article/pii/S0038080617301166#!
DO - https://doi.org/10.1016/j.sandf.2017.08.014
SN - 0038-0806
VL - 57
IS - 5
SP - 861
EP - 871
PB - Elsevier B.V.
AN - OPUS4-42994
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kannengießer, Thomas
A1 - Kromm, Arne
T1 - Formation of welding residual stresses in low transformation temperature (LTT) materials
N2 - For the safety and cost efficiency of welded high-strength steel structures, precise knowledge of the level and distribution of welding- and cooling-specific stresses and residual stresses is essential, since they exert a decisive influence on strength, crack resistance, and finally on the bearable service load. This paper presents innovative filler materials, of which the phase transformation temperature was deliberately adjusted via the chemical composition. The transformation behaviour of these martensitic Low Transformation Temperature (LTT-) filler materials shows direct effects on the local residual stresses in the weld and the HAZ. These effects can purposefully be exploited to counteract the thermally induced shrinkage of the material and to produce significant compressive residual stresses in the weld. Comparative welding experiments were carried out on 690 MPa high-strength base materials using various LTT-filler materials. High energy synchrotron radiation was used for residual stress measurement. Particularly the use of high energy synchrotron radiation makes it possible to detect the residual stress condition fast without destruction of material. Thereby, residual stress depth gradients can be determined simultaneously without removing material. In steel, gradients of up to 150 µm can be resolved in such a way. Furthermore, the application of high energy radiation permits determination of residual stresses of any available residual austenite contents. Results show significant dependence of transformation temperatures on the resulting residual stress level and distribution.
KW - Phase specific residual stresses
KW - Phase transformation
KW - Low transformation temperature filler wire
KW - Energy dispersive diffraction
KW - High strength steel
PY - 2009
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-205909
DO - https://doi.org/10.1590/S0104-92242009000100009
SN - 0104-9224
SN - 1980-6973
VL - 14
IS - 1
SP - 74
EP - 81
PB - Associação Brasileira de Soldagem, ABS
CY - Rio de Janeiro
AN - OPUS4-20590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schneider, Ralf
A1 - Weigert, Florian
A1 - Lesnyak, V.
A1 - Leubner, S.
A1 - Lorenz, T.
A1 - Behnke, Thomas
A1 - Dubavik, A.
A1 - Joswig, J.-O.
A1 - Resch-Genger, Ute
A1 - Gaponik, N.
A1 - Eychmüller, A.
ED - Resch-Genger, Ute
ED - Schneider, Ralf
T1 - pH and concentration dependence of the optical properties of thiol-capped CdTe nanocrystals in water and D2O
N2 - The optical properties of semiconductor nanocrystals (SC NCs) are largely controlled by their size and surface chemistry, i.e., the chemical composition and thickness of inorganic passivation shells and the chemical nature and number of surface ligands as well as the strength of their bonds to surface atoms.
The latter is particularly important for CdTe NCs, which – together with alloyed CdₓHg₁₋ₓTe – are the only SC NCs that can be prepared in water in high quality without the need for an additional inorganic passivation shell. Aiming at a better understanding of the role of stabilizing ligands for the control of the application-relevant fluorescence features of SC NCs, we assessed the influence of two of the most commonly used monodentate thiol ligands, thioglycolic acid (TGA) and mercaptopropionic acid (MPA),
on the colloidal stability, photoluminescence (PL) quantum yield (QY), and PL decay behavior of a set of CdTe NC colloids. As an indirect measure for the strength of the coordinative bond of the ligands to SC NC surface atoms, the influence of the pH (pD) and the concentration on the PL properties of these colloids was examined in water and D₂O and compared to the results from previous dilution studies with a set of thiol-capped Cd₁₋ₓHgₓTe SC NCs in D₂O. As a prerequisite for these studies, the number of surface ligands was determined photometrically at different steps of purification after SC NC synthesis with Ellman’s test.
Our results demonstrate ligand control of the pH-dependent PL of these SC NCs, with MPA-stabilized CdTe NCs being less prone to luminescence quenching than TGA-capped ones. For both types of CdTe colloids, ligand desorption is more pronounced in H₂O compared to D₂O, underlining also the role of hydrogen bonding and solvent molecules.
KW - Quantum dots
KW - Fluorescence
KW - Ligand analysis
KW - Nano particles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371253
DO - https://doi.org/10.1039/c6cp03123d
VL - 18
IS - 28
SP - 19083
EP - 19092
PB - RSC
CY - Cambridge
AN - OPUS4-37125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roebben, G.
A1 - Kestens, V.
A1 - Varga, Z.
A1 - Charoud-Got, J.
A1 - Ramaye, Y.
A1 - Gollwitzer, Christian
A1 - Bartczak, D.
A1 - Geißler, Daniel
A1 - Noble, J.E.
A1 - Mazoua, S.
A1 - Meeus, N.
A1 - Corbisier, P.
A1 - Palmai, M.
A1 - Mihály, J.
A1 - Krumrey, M.
A1 - Davies, J.
A1 - Resch-Genger, Ute
A1 - Kumarswami, N.
A1 - Minelli, C.
A1 - Sikora, A.
A1 - Goenaga-Infante, H.
T1 - Reference materials and representative test materials to develop nanoparticle characterization methods: the NanoChOp project case
N2 - This paper describes the production and characteristics of the nanoparticle test materials prepared for common use in the collaborative research project NanoChOp (Chemical and optical characterization of nanomaterials in biological systems), in casu suspensions of silica nanoparticles and CdSe/CdS/ZnS quantum dots (QDs). This paper is the first to illustrate how to assess whether nanoparticle test materials meet the requirements of a "reference material" (ISO Guide 30, 2015) or rather those of the recently defined category of "representative test material (RTM)" (ISO/TS 16195, 2013). The NanoChOp test materials were investigated with small-angle X-ray scattering (SAXS), dynamic light scattering (DLS), and centrifugal liquid sedimentation (CLS) to establish whether they complied with the required monomodal particle size distribution. The presence of impurities, aggregates, agglomerates, and viable microorganisms in the suspensions was investigated with DLS, CLS, optical and electron microscopy and via plating on nutrient agar. Suitability of surface functionalization was investigated with attenuated total reflection Fourier transform infrared spectrometry (ATR-FTIR) and via the capacity of the nanoparticles to be fluorescently labeled or to bind antibodies. Between-unit homogeneity and stability were investigated in terms of particle size and zeta potential. This paper shows that only based on the outcome of a detailed characterization process one can raise the status of a test material to RTM or reference material, and how this status depends on its intended use.
KW - Nanoparticle
KW - Materials characterization
KW - Reference material
KW - Analytical quality assurance
KW - Metrology
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-349644
DO - https://doi.org/10.3389/fchem.2015.00056
SN - 2296-2646
VL - 3
SP - Article 56, 1
EP - 16
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-34964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nöller, R.
A1 - Hahn, Oliver
T1 - Illuminated manuscripts from Turfan - Tracing Silk Road glamour by analyzing pigments
N2 - Investigation of manuscripts found in sites along the Silk Road shows the history of communication and exchange between Asia and the Mediterranean over the centuries. Different scripts and languages preserved on paper in certain styles provide information about traditions and provenance.
To get an idea of the cultural background of the highly developed painting techniques obvious in some illuminated manuscripts, the material used for writing and painting is analyzed. Singular Sogdian and Tocharian manuscripts from Turfan show text on one side with a colorful painting on the other side of the document. In comparison with other productions of different periods or usages from the site, special features are worked out to characterize cultural roots or influence in the network of relationships. Details analyzed in the most elaborated documents Show various influences led to the colorful masterpieces.
KW - Pigments
KW - X-ray fluorescence analysis
KW - Archaeometry
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391654
DO - https://doi.org/10.1080/20548923.2015.1133120
SN - 2054-8923
VL - 1
IS - 2
SP - 50
EP - 59
PB - Routledge, Taylor & Francis Group
AN - OPUS4-39165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mull, Birte
A1 - Horn, Wolfgang
A1 - Jann, Oliver
T1 - Methode zur Bestimmung von flüchtigen Estern der Phthalsäure im Innenraum und in Emissionsmesskammern
N2 - Die Analytik von Phthalaten (DMP bis DEHP) in der Luft ist mit thermischer Desorption unter Verwendung von Quarzwolle als Adsorbens erfolgreich realisierbar. Dies wurde durch eine Methodenvalidierung bestätigt. Es wurden sowohl Messungen im Innenraum als auch in Emissionskammern vorgenommen. In den Emissionskammermessungen wurden mögliche Senkeneffekte der Kammeroberfläche (Glas) untersucht. Unter Zuhilfenahme der idealen Abklingkurve wird bestätigt, dass diese Oberfläche eine Senke darstellt.
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-209870
UR - http://www.gefahrstoffe.de
SN - 0949-8036
SN - 1436-4891
VL - 70
IS - 3
SP - 93
EP - 97
PB - VDI Fachmedien
CY - Düsseldorf
AN - OPUS4-20987
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Matthias
A1 - Schühle, Florian
T1 - Experimental determination of 7-day uptake rates for diffusive sampling of 86 volatile and semi-volatile organic compounds relevant for indoor air monitoring and investigation on their sensitivity to exposure time and indoor climate
N2 - This study aimed to experimentally determine uptake rates for 86 indoor relevant volatile and semi-volatile organic compounds (VOC, SVOC) for the passive sampler type Perkin Elmer/Markes™ with Tenax® TA as sorbent, which was used in the German Environmental Survey on Health (GerES VI) carried out by the German Environmental Agency (UBA) in the years 2023-2024. For this purpose, single reference gas atmospheres of 76 pure VOCs (liquid at room temperature) and a group of 10 SVOCs and VOCs (solid at room temperature) were generated using two generation procedures. By exposing the samplers to individual components, it was ruled out that interactions in a mixture have a influence on the uptake rate. Another aspect was to precisely describe the methodology and the resulting uncertainties, as there are gaps in the literature in this regard. The selection of the compounds was based on the findings of the preceding GerES V study for which data was missing or needed to be verified. In each experiment, a number of six passive samplers was exposed to the test gas atmospheres in dynamically operated exposure chambers for seven days. The sensitivity of the uptake rates of a group of 10 selected VOCs to variations in exposure time, ambient temperature, and air humidity in a multi-component reference gas atmosphere was investigated. Here, a decrease in the uptake rate with the exposure time could be observed stabilising from the fifth day of exposure onwards. A significant effect of temperature and humidity on the uptake rate was not apparent. The determined uptake rates exhibit uncertainties of < 20 % for 71 substances, and < 10 % for 51 substances which are also in good agreement with the literature, if already published elsewhere. The quantity of investigated substances, the detailed description of the methodology used to determine the uptake rates complemented by the respective uncertainties, as well as the compilation of comparative data, contribute to a better assessment of the quality and relevance of such data, which had not been published before.
KW - Indoor air quality
KW - Volatile organic compounds
KW - Uptake rates
KW - Passive sampling
KW - Tenax TA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629913
DO - https://doi.org/10.1016/j.indenv.2025.100095
VL - 2
IS - 2
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-62991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berry, Charlotte A.
A1 - Reinart, Katre
A1 - Smales, Glen J.
A1 - Wilkinson, Holly N.
A1 - Hardman, Matthew J.
A1 - Marchesini, Sofia
A1 - Lee, William
A1 - Nery, Eveliny Tomás
A1 - Moghaddam, Zarrin
A1 - Hoxha, Agron
A1 - Felipe-Sotelo, Mónica
A1 - Gutierrez-Merino, Jorge
A1 - Carta, Daniela
T1 - Hierarchically porous copper and gallium loaded sol–gel phosphate glasses for enhancement of wound closure
N2 - In this work, we have developed hierarchically porous phosphate-based glasses (PPGs) as novel materials capable of promoting wound closure and simultaneously delivering antibacterial effects at the glass-biological tissue interface. PPGs are characterised by extended porosity, which enhances the controlled release of therapeutic ions, whilst facilitating cell infiltration and tissue growth. Two series of PPGs in the systems P2O5–CaO–Na2O–CuO and P2O5–CaO–Na2O–Ga2O3 with (CuO and Ga2O3 0, 1, 5 and 10 mol%) were manufactured using a supramolecular sol–gel synthesis strategy. Significant wound healing promotion (up to 97%) was demonstrated using a human ex vivo wound model. A statistically significant reduction of the bacterial strains Staphylococcus aureus and Escherichia coli was observed in both series of PPGs, particularly those containing copper. All PPGs exhibited good cytocompatibility on keratinocytes (HaCaTs), and analysis of PPG dissolution products over a 7-day period demonstrated controlled release of phosphate anions and Ca, Na, Cu, and Ga cations. These findings indicate that Cu- and Ga-loaded PPGs are promising materials for applications in soft tissue regeneration given their antibacterial capabilities, in vitro biocompatibility with keratinocytes and ex vivo wound healing properties at the biomaterial-human tissue interface.
KW - Porous glass
KW - Phosphates
KW - Wound healing materials
KW - Antibacterial
KW - X-ray scattering
KW - MOUSE
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650867
DO - https://doi.org/10.1039/d5tb01945a
SN - 2050-750X
VL - 13
IS - 48
SP - 15662
EP - 15677
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nattuveettil, Keerthana
A1 - Liebner, Christian
A1 - Tiebe, Carlo
T1 - Hydrogen safety- Dealing with Closed Spaces
N2 - Hydrogen is under discussion as a potentially clean energy source, but its safe usage and handling in enclosed environments remains a critical challenge due to the properties of hydrogen. This work focuses on detecting and monitoring hydrogen concentration in closed spaces to improve safety by developing a sensor network-based leak detection system to prevent of the accumulation of hazardous mixtures. Furthermore, the study details the implementation of a hydrogen sensor network within a container, analysing sensor placement, data collection, and safety improvements. The findings contribute to better risk assessment and enhanced safety protocols in hydrogen storage and usage facilities.
T2 - SMSI 2025
CY - Nuremberg, Germany
DA - 06.05.2025
KW - Sensor Network
KW - Hydrogen safety
KW - QI-Digital
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640630
SN - 978-3-910600-06-5
DO - https://doi.org/10.5162/SMSI2025/C6.2
SP - 167
EP - 168
PB - AMA Verband für Sensorik und Messtechnik e.V.
CY - Berlin
AN - OPUS4-64063
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Solberg, S. B. B.
A1 - Zimmermann, P.
A1 - Wilhelmsen, Ø.
A1 - Bock, Robert
A1 - Burheim, O. S.
T1 - Analytical treatment of ion-exchange permselectivity and transport number measurements for high accuracy
N2 - We analyse electromotive force measurements of concentration cells using non-equilibrium thermodynamics, and determine the transference coefficients of ion-exchange membranes in aqueous KCl solutions. By taking advantage of the analytical expression for the permselectivity, we extract transport coefficients with high accuracy. The transport number of K+ and the transference coefficient of water in the Selemion CMVN cationexchange membrane are found to be 100𝑡K+ = 99.59 ± 0.56 and 𝑡𝑤 = 3.69 ± 0.40 respectively, while for the Selemion AMVN anion-exchange membrane they are 100𝑡Cl− = 100.21 ± 0.37 and 𝑡𝑤 = −3.75 ± 0.27. These results suggest that the membranes are perfectly selective to the target ion, and that each ion carries 3-4 water molecules through the membrane, which reduces the membrane permselectivity. In these concentration cells, the electrical potential contribution of the membrane alone was more easily isolated with bare Ag/AgCl electrodes without reference solutions and liquid junction plugs. Additionally, we find a large contribution to the measured concentration cell voltage from concentration gradients across the porous plug of the reference electrode, which cannot be explained by Henderson’s equation alone. For most of the concentration range, the transport number of the porous plug is determined to be 100𝑡K+ = 49.43 ± 0.78 with negligible water transport, similar to literature values for bulk electrolyte. In dilute electrolyte solutions with concentrations below 0.1 mol kg−1, the plug shows anomalous behaviour consistent with an increase in K+ selectivity and water co-transport.
KW - Ion-exchange membranes
KW - Electrodialysis
KW - Non-equilibrium thermodynamics
KW - Electroosmosis
KW - Transport number
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580654
DO - https://doi.org/10.1016/j.memsci.2023.121904
SN - 1873-3123
VL - 2023
IS - 685
PB - Elsevier
CY - New York, NY [u.a.]
AN - OPUS4-58065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eberwein, Robert
A1 - Hajhariri, Aliasghar
A1 - Davide, Camplese
A1 - Giordano, Emrys Scarponi
A1 - Valerio, Cozzani
A1 - Frank, Otremba
T1 - Experimental investigation on the behavior of thermal super insulation materials for cryogenic storage tanks in fire incidents
N2 - The number of vehicles using or transporting cryogenic fuels such as Liquefied Hydrogen (LH2) or Liquefied Natural Gas (LNG) increases fast in the land transportation sector. Does this also entail new risks? The storage of cryogenic fuels requires tanks with Thermal Super Insulations (TSI) to keep the fluid cold and limit the formation of boil-off gas. TSI has proven itself in some applications since the middle of the 20th century, but in the land transport sector they are still quite new, where accidents involving fires, collisions, and their combination are to be expected. This work focuses on investigating the behavior of different types of TSI while exposed to a heat source representing a fire. To this aim, a High-Temperature Thermal Vacuum Chamber (HTTVC) was applied, which allows the thermal loading of a thermal insulation material in a vacuum and measuring the heat flow transported through the TSI in parallel. In this study, the results of 6 samples are presented regarding 3 types of MLI, rock wool, perlites, and microspheres. The thermal exposure caused different effects on the samples. In practice, this can be connected to the rapid release of flammable gases as well as to a Boiling Liquid Expanding Vapour Explosion (BLEVE). These results are relevant for reducing the risks to people and infrastructures in the progressive establishment of tanks for cryogenic fluids in our industry and society. The data presented in the study can be used to improve the design of tanks and TSIs, the assessment of accident scenarios, and the development of measures for first responders.
KW - Liquefied hydrogen
KW - Liquefied natural gas
KW - Tanks
KW - Fire
KW - Insulation
KW - MLI
KW - Perlite
KW - Rock wool
KW - Microspheres
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599947
DO - https://doi.org/10.1016/j.psep.2024.04.131
SN - 0957-5820
VL - 187
SP - 240
EP - 248
PB - Elsevier
AN - OPUS4-59994
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Theiler, Geraldine
A1 - Cano Murillo, Natalia
A1 - Halder, Karabi
A1 - Balasooriya, Winoj
A1 - Hausberger, Andreas
A1 - Kaiser, Andreas
T1 - Effect of high-pressure hydrogen environment on the physical and mechanical properties of elastomers
N2 - This study presents the influence of high-pressure hydrogen environment on the physical and mechanical properties of two types of cross-linked hydrogenated acrylonitrile butadiene rubbers. Based on the CSA/ANSI standard, static exposures in hydrogen experiments were performed up to 100 MPa at 120 °C. Characterization before and after exposure was conducted by means of density and hardness measurements, dynamic mechanical analysis (DMA), tensile tests, compression set, FT-IR and AFM analyses to assess effects after decompression. While the effect of high-pressure exposure is significant immediately after exposure, most of the physical and mechanical properties recover after 48 hours. FT-IR, AFM, SEM and compression set results indicate, however, permanent effects.
KW - Hydrogen
KW - Mechanical properties
KW - Elastomers
KW - High-pressure hydrogen environment
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597102
DO - https://doi.org/10.1016/j.ijhydene.2024.01.148
SN - 0360-3199
VL - 58
SP - 389
EP - 399
PB - Elsevier Ltd.
AN - OPUS4-59710
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tahri, K.
A1 - Tiebe, Carlo
A1 - El Bari, N.
A1 - Hübert, Thomas
A1 - Bouchikhi, B.
T1 - Geographical classification and adulteration detection of cumin by using electronic sensing coupled to multivariate analysis
N2 - The objective of this work is to report the improvement obtained in the discrimination of complex aroma and taste with subtle differences in odor and flavor, by the use of fast suitable procedures for the cases of measurements in the field demanding decision-making in real time. The proposed electronic sensing systems, formed by an E-nose and VE-tongue, were used to discriminate cumin cultivars from different geographical origins, as well as to quantify the cumin adulteration percentages by using unsupervised and supervised chemometric tools. Thus, the results obtained are sufficiently encouraging as a starting point for the development of new electronic sensing systems with more improvement such the reliability of the sensors’ performance as well as the chemometric tools in order to deal with a complex dataset.
KW - VE-tongue
KW - E-nose
KW - Chemometric tools
KW - Cumin discrimination
KW - Geographical origins
KW - Adulteration detection
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-409735
DO - https://doi.org/10.1016/j.protcy.2017.04.102
SN - 2212-0173
VL - 27
SP - 240
EP - 241
PB - Elsevier B.V.
AN - OPUS4-40973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Theiler, Geraldine
A1 - Cano Murillo, Natalia
A1 - Hausberger, Andreas
T1 - Effect of hydrogen pressure on the fretting behavior of rubber materials
N2 - Safety and reliability are the major challenges to face for the development and acceptance of hydrogen technology. It is therefore crucial to deeply study material compatibility, in particular for tribological components that are directly in contact with hydrogen. Some of the most critical parts are sealing materials that need increased safety requirements. In this study, the fretting behavior of several elastomer materials were evaluated against 316L stainless steel in an air and hydrogen environment up to 10 MPa. Several grades of cross-linked hydrogenated acrylonitrile butadiene (HNBR), acrylonitrile butadiene (NBR) and ethylene propylene diene monomer rubbers (EPDM) were investigated. Furthermore, aging experiments were conducted for 7 days under static contions in 100 MPa of hydrogen followed by rapid gas decompression. Fretting tests revealed that the wear of these compounds is significantly affected by the hydrogen environment compared to air, especially with NBR grades. After the aging experiment, the friction response of the HBNR grades is characterized by increased adhesion due to elastic deformation, leading to partial slip.
KW - Fretting wear
KW - Rubbers
KW - Hydrogen
KW - High-pressure
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608462
DO - https://doi.org/10.3390/lubricants12070233
VL - 12
IS - 7
SP - 1
EP - 17
PB - MDPI
AN - OPUS4-60846
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte-Ruiz, D.
A1 - Saßnick, H.-D.
A1 - Ferreira De Araujo, F.
A1 - Gentzmann, Marie
A1 - Huthwelker, T.
A1 - Cocchi, C
T1 - X-ray absorption spectroscopy of scandium oxide polymorphs
N2 - Scandium oxide (Sc2O3) is a rare-earth oxide with significant potential in key technological areas, but due to its limited supply a deep understanding of its characteristics in different crystalline phases is still missing. Here, we present a combined experimental and ab initio X-ray absorption spectroscopy investigation of Sc2O3 focusing on excitations from the O K-edge and the Sc L2,3-edge. While measurements are performed on a cubic sample, the most stable phase under ambient conditions, six different polymorphs are computed, including two high-pressure phases with a trigonal and monoclinic lattice in addition to the cubic phase, as well as three computationally predicted structures. Our analysis of the structural and electronic properties reveals significant similarities between the cubic polymorph and the high-pressure trigonal phase, while the monoclinic crystal exhibits distinct features. The spectra simulated for these similar phases from the solution of the Bethe–Salpeter equation show very good agreement with measurements. Additional comparison with results computed in the independent-particle approximation highlights the dominant role of electron–hole correlations in shaping the absorption features, particularly at the O K-edge, where a common pattern with the features of other sesquioxides is identified. Our findings offer new insight into the spectral fingerprints of Sc2O3 polymorphs, aiding in situ characterization and informing sustainable materials management.
KW - Scandium
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650806
DO - https://doi.org/10.1039/d5ra06446e
VL - 15
IS - 56
SP - 47814
EP - 47825
AN - OPUS4-65080
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iskhakov, Tagir
A1 - Breese, Philipp
A1 - Altenburg, Simon
A1 - Hilgenberg, Kai
T1 - Numerical and experimental analysis of temperature compensation for eddy current testing during laser powder bed fusion
N2 - The quality of parts produced via laser powder bed fusion (PBF-LB/M) can be affected by microstructural defects inherent to the process. In-situ monitoring technologies are crucial for ensuring consistent component quality. Eddy current testing (ECT) offers a viable method for real time monitoring during the PBF-LB/M build cycle. However, complex temperature fields arising during manufacturing significantly impact electrical conductivity, posing a challenge for ECT accuracy. Thus, precise temperature distribution prediction is essential for reliable flaw detection. This study develops a Finite Element (FE) model to predict the temperature field in multi-part build cycles. Scan vectors are grouped into clusters based on their timestamps, enabling the homogenization of thermal loads from multiple scan vectors. This approach allows for optimizing the trade-off between modeling accuracy and computational efficiency in a multi-part build. The study assesses the prediction accuracy required for ECT and investigates the appropriate level of homogenization needed to achieve it. Model predictions are validated through comparisons with thermography images and thermocouple measurements conducted during the manufacturing of 316L steel components.
KW - PBF-LB/M
KW - FEM
KW - Heat accumulation
KW - Eddy current testing
KW - 316L
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650165
DO - https://doi.org/10.1007/s40964-025-01429-2
SP - 1
EP - 20
PB - Springer Nature
AN - OPUS4-65016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sun, Yijuan
A1 - Pérez-Padilla, Víctor
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Ratiometric detection of perfluoroalkyl carboxylic acids using dual fluorescent nanoparticles and a miniaturised microfluidic platform
N2 - The widespread contamination of soil and water with perfluoroalkyl substances (PFAS) has caused considerable societal and scientific concern. Legislative measures and an increased need for remediation require effective on-site analytical methods for PFAS management. Here we report on the development of a green-fluorescent guanidine-BODIPY indicator monomer incorporated into a molecularly imprinted polymer (MIP) for the selective detection of perfluorooctanoic acid (PFOA). Complexation of PFOA by the indicator, which is mediated by concerted protonation-induced ion pairing-assisted hydrogen bonding, significantly enhances fluorescence in polar organic solvents. The MIP forms as a thin layer on silica nanoparticles doped with tris(bipyridine)ruthenium(II) chloride, which provides an orange emission signal as internal reference, resulting in low measurement uncertainties. Using a liquid-liquid extraction protocol, this assay enables the direct detection of PFOA in environmental water samples and achieves a detection limit of 0.11 µM. Integration into an opto-microfluidic system enables a compact and user-friendly system for detecting PFOA in less than 15 minutes.
KW - PFAS
KW - Molecular imprinting
KW - Microfluidics
KW - Fluorescence
KW - Onsite assay
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650270
DO - https://doi.org/10.1038/s41467-025-66872-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gant, Simon
A1 - Chang, Joseph
A1 - Hetherington, Rory
A1 - Hanna, Steven
A1 - Tickle, Gemma
A1 - Spicer, Tom
A1 - McMasters, Sun
A1 - Fox, Shannon
A1 - Meris, Ron
A1 - Bradley, Scott
A1 - Miner, Sean
A1 - King, Matthew
A1 - Simpson, Steven
A1 - Mazzola, Thomas
A1 - McGillivray, Alison
A1 - Tucker, Harvey
A1 - Björnham, Oscar
A1 - Carissimo, Bertrand
A1 - Fabbri, Luciano
A1 - Wood, Maureen
A1 - Habib, Abdel Karim
A1 - Harper, Mike
A1 - Hart, Frank
A1 - Vik, Thomas
A1 - Helgeland, Anders
A1 - Howard, Joel
A1 - Mauri, Lorenzo
A1 - Mackie, Shona
A1 - Mack, Andreas
A1 - Lacome, Jean-Marc
A1 - Puttick, Stephen
A1 - Ibrahim, Adeel
A1 - Miller, Derek
A1 - Dharmavaram, Seshu
A1 - Shen, Amy
A1 - Cunningham, Alyssa
A1 - Beverly, Desiree
A1 - O’Neal, Daniel M.
A1 - Verdier, Laurent
A1 - Burkhart, Stéphane
A1 - Dixon, Chris
A1 - Nilsen, Sandra
A1 - Bradley, Robert
A1 - Skarsvåg, Hans L.
A1 - Fyhn, Eirik H.
A1 - Aasen, Ailo
T1 - Pressure-Liquefied Ammonia Jet Dispersion: Multi-Model Intercomparison Using Desert Tortoise and FLADIS Field Data
N2 - This paper presents the findings of an international model inter-comparison exercise that was undertaken in the period 2021-2024 to assess the performance of atmospheric dispersion models for simulating releases of pressure-liquefied ammonia. The exercise used data from ammonia field trials dating from the 1980s and 1990s: the Desert Tortoise and the FLADIS trials. Concentration data from two arcs of sensors in the Desert Tortoise trials and three arcs of sensors in the FLADIS trials were used. Twenty-one independent modelling teams from North America and Europe participated in the exercise and provided in total twenty-seven sets of results from a range of different models, including empirically-based nomograms, integral, Gaussian puff, Lagrangian particle, and Computational Fluid Dynamics (CFD) models. The work is novel in presenting the results from such a large cohort of models, examining specifically the dispersion behaviour of ammonia. This is particularly relevant at the current time, given the growing international interest in using ammonia as a clean energy vector and shipping fuel.
The study found that the agreement between model predictions and measurements (as determined by performance measures such as geometric mean bias and geometric variance) varied between different models. At any downwind distance, the range in predicted plume arc-max concentrations spanned a range of up to one or two orders of magnitude about the measurements. Several modelling teams used the same models and, in most cases, their predictions differed. Given appropriate inputs, most models generally predicted concentrations that agreed with the data within commonly-used model acceptance criteria. There was no single class of model that provided superior predictions to others; predictions from several empirically-based nomograms, integral, Gaussian puff, Lagrangian particle, and CFD models were all in close agreement with the data (as defined by the model acceptance criteria).
The findings of the exercise are being used to help plan a programme of future ammonia experiments in the USA, called the Jack Rabbit III trials. The results are also useful for assessing the performance of models that may be applied to assess risks at ammonia facilities, and for emergency planning and response.
KW - Ammonia
KW - Atmospheric dispersion
KW - Validation
KW - Jack rabbit
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646069
DO - https://doi.org/10.1016/j.aeaoa.2025.100389
SN - 2590-1621
VL - 28
SP - 1
EP - 76
PB - Elsevier Ltd.
AN - OPUS4-64606
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernardy, Christopher
A1 - Habib, Abdel Karim
A1 - Kluge, Martin
A1 - Schalau, Bernd
A1 - Kant, Hanjo
A1 - Schulze, Marcel
A1 - Orchini, Alessandro
T1 - Experimental Investigation of Large-Scale Hydrogen Diffusion Jet Flames
N2 - Hydrogen is a promising alternative to natural gas in industrial energy applications to limit global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). Most existing data on thermal radiation are based on unsteady flow conditions and/or still air, whereas the experiments carried out here ensure a constant mass flow under realistic free-field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Based on the investigations, empirical equations for modelling jet flames could be derived.
T2 - Proceedings of ASME Turbo Expo 2025 Turbomachinery Technical Conference and Exposition
CY - Memphis, Tennessee, USA
DA - 16.06.2025
KW - Hydrogen release
KW - Radiant heat fraction
KW - Thermal radiation
KW - Jet flame
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643401
DO - https://doi.org/10.1115/1.4070012
SN - 0742-4795
VL - 148
IS - 5
SP - 51008-1
EP - 51008-8
PB - ASME International
AN - OPUS4-64340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ji, Y.
A1 - Mezhov, Alexander
A1 - Wang, S.
A1 - Stephan, D.
T1 - Influence of polycarboxylate superplasticizers with different molecular structures on rheological properties of glass bead suspension at different resting times
N2 - Using an inert glass bead suspension, the study explores the interaction between various PCE superplasticizers, ions and investigates how it affects rheological performance during resting. To understand the underlying mechanisms, surface charge properties, adsorption, aggregates amount, and size of PCE during resting were measured. Results showed that yield stress increased with time, mainly when a high PCE dosage was used, and the modulus from strain sweep experiments agreed with the yield stress variations. The increase in zeta potential value and decrease in aggregate amount explain the decrease in yield stress in the non-PCE sample but are inconsistent with the increase in yield stress in presence of PCE. The PCE clusters’ size increases during resting, and increasing PCE adsorption does not disperse the glass bead particles. In addition, compared to the amount of carboxylate group, the molecular weight of PCE is more dominant in increasing the yield stress during resting.
The increase in yield stress could be explained by the increase in the bridging and depletion forces due to the increasing size of the PCE cluster. Another possible reason is that non-adsorbed PCE clusters may form a polymer network that restricts the movement of the particles.
KW - Glass bead
KW - Rheological performance
KW - PCE superplasticizers
KW - Ion
KW - Resting time
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617609
DO - https://doi.org/10.1016/j.colsurfa.2024.133583
SN - 0927-7757
VL - 688
IS - 133583
SP - 1
EP - 12
PB - Elsevier B.V.
CY - Schweiz
AN - OPUS4-61760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schönsee, Eric
A1 - Hüsken, Götz
A1 - Jeyifous, Olubunmi Anthony
A1 - Mezhov, Alexander
A1 - Strangfeld, Christoph
T1 - Calculating rheological properties of fresh mortar for additive manufacturing based on experimental, multi-sensor data
N2 - Additive manufacturing of concrete structures is a novel and emerging technology. Freecontouring in civil engineering, which allows for entirely new designs, is a significant advantage. Inthe future, lower construction costs are expected with increased construction speeds and decreasingrequired materials and workers. However, architects and civil engineers rely on a certain quality ofexecution to fulfil construction standards. Although several techniques and approaches demonstratethe advantages, quality control during printing is highly challenging and rarely applied. Due to thecontinuous mixing process commonly used in 3D concrete printing, it is impossible to exclude varia-tions in the dry mixture or water content, and a test sample cannot be taken as a representative samplefor the whole structure. Although mortar properties vary only locally, a defect in one layer duringprinting could affect the entire integrity of the whole structure . Therefore, real-time process monitor-ing is required to record and document the printing process.At the Bundesanstalt für Materialforschung und -prüfung (BAM) a new test rig for the additive man-ufacturing of concrete is built. The primary purpose is measuring and monitoring the properties of amortar during the printing process.The following study investigates an approach for calculating yield stress and plastic viscosity based onexperimentally recorded pressure data. The calculations assume that fresh mortar behaves as a Bing-ham fluid and that the Buckingham-Reiner-equation is applicable. A test setup consisting of rigid pipeswith integrated pressure sensors at different positions is utilized.Monitoring the printing process with different sensors is crucial for the quality control of an ongoingprocess.
T2 - Non-Traditional Cement and Concrete 2023 Conference
CY - Brno, Czech Republic
DA - 25.06.2023
KW - 3DCP
KW - Monitoring
KW - Additive manufacturing
KW - Rheology
KW - Bingham fluid
KW - Concrete printing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598179
DO - https://doi.org/10.4028/p-EV4gPv
SN - 1662-0356
VL - 145
SP - 131
EP - 139
PB - Trans Tech Publications
CY - Baech
AN - OPUS4-59817
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sathiyamani, S.
A1 - Ngiam, S.
A1 - Bonnerot, O.
A1 - Jaengsawang, S.
A1 - Panarut, P.
A1 - Helman-Wazny, Agnieszka
A1 - Colini, C.
T1 - Material Characterisation of 19–20th Century Manuscripts from Northern Thailand
N2 - Material analysis was carried out on four manuscripts from Northern Thailand, which included two palm-leaf manuscripts and two paper manuscripts. The two palm-leaf manuscripts MS 6 and MS 7 were found to have been written in the traditional method, wherein text was incised on the surface of the leaves, and then soot applied to the surfaces, confirmed by the identification of carbon ink. MS 7 additionally showed the presence of trace levels of iron in the ink, either from soot paste or from the stylus used for inscribing. The paper manuscript MS 3 was written in iron-gall ink, with sections written using a methyl-violet based ink while MS 4 was written in carbon ink. The paper used in the case of MS 3 was found to be machine made, while khoi fibres (Streblus asper) were used for making the paper used for MS 4. A combination of traditional and modern pigments, like molybdenum orange, was used for decorating the edges and cover. The results improved our understanding of these manuscripts in particular, and also provided us with insights about the rapid adoption of modern materials and their incorporation into the production of written artefacts from Northern Thailand in the late 19th and early 20th centuries.
KW - Materials analysis
KW - Paper manuscript
KW - Palm-leaf manuscript
KW - Writing inks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652586
DO - https://doi.org/10.1515/res-2023-0028
SN - 0034-5806
VL - 45
IS - 2-3
SP - 117
EP - 140
PB - Walter de Gruyter GmbH
AN - OPUS4-65258
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Simon
A1 - Pittrich, Tim
A1 - Stelzner, Ludwig
A1 - Weise, Frank
A1 - Meschke, Günther
T1 - Concretes containing blended-cements with reduced carbon-dioxide emissions: A chemo-thermo-hygro-mechanical model for elevated temperatures
N2 - A comprehensive analysis aimed at understanding and assessing the high-temperature behavior of concretes containing blended cements (CEM III/A, CEM II/B-Q, and CEM IV), characterized by low carbon-dioxide emissions (during clinker’s production) is necessary to reliably model the damage in the concrete, thermal spalling included. To this purpose, a numerical chemo-thermo-hygro-mechanical model is formulated, to investigate – among other phenomena – heat transmission and pore pressure for different aggregate types.
Based on an available hydration model, a dehydration model is established to numerically investigate the evolution of dehydration and porosity at elevated temperatures. Based on the properties of concrete and cement constituents on multiple scales, an analytical homogenization process is proposed to predict the thermal conductivity of the concrete. This process is later validated and implemented into a macroscopic modeling framework.
Chemo-thermo-hygro-mechanical analyses show that the dehydration characteristics of blended low carbon-dioxide release cements may increase pore pressure in the concrete by up to 13% compared to the concrete containing ordinary Portland cement. In addition, aggregates exhibiting high thermal conductivity may contribute to a further increase (even more than 35%) in pore pressure compared to aggregates with low thermal conductivity.
Last but not least, the proposed model provides the basis for the reduction of the number of the parameters commonly required in the chemo-thermo-hygro-mechanical modeling of cementitious materials.
KW - Concrete at high temperature
KW - Dehydration
KW - Multiscale modeling
KW - Thermal conductivity
KW - Chemo-hygro-thermal analysis
KW - Micromechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635894
DO - https://doi.org/10.1016/j.cemconcomp.2025.106163
SN - 0958-9465
VL - 163
SP - 1
EP - 17
PB - Elsevier
CY - Amsterdam
AN - OPUS4-63589
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezhov, Alexander
A1 - Goncharov, A.
A1 - Zhutovsky, S.
A1 - Kovler, K.
A1 - Diesendruck, Ch. E.
T1 - The Impact of DNA as a Chemical Admixture for Cementitious Materials
N2 - Viscosity modifying agents (VMA) and superplasticizers (SP) are two common macromolecular admixture types for cementitious materials. VMAs are used to stabilize fresh cementitious materials, while SPs are used to disperse them. Most VMAs are bio-based polysaccharides that act in the water phase between particles; while most SPs are synthetic comb polymers, consisting of negatively charged backbones that help their adsorption to the cement particles' surface. The molecular structure of DNA contains elements of VMA – as it is a polysaccharide – and SP – as it is a polyanion. In this study, rheological measurements are used to compare how these three types of macromolecules (VMA, SP, and DNA) affect cementitious materials. It is found that DNA shows the combined effects of VMAs and SPs on cement paste: it lowers yield stress while at the same time maintaining or even increasing its viscosity, which permits reducing water content while avoiding bleeding or segregation of samples. Yet, the presence of DNA has a significant retardation impact on cement hydration, which is also a common side effect of VMAs and SPs.
KW - Impact of DNA
KW - Viscosity modifying agents (VMA)
KW - Superplasticizers (SP)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638542
DO - https://doi.org/10.1002/admt.202500073
SN - 2365-709X
VL - 10
IS - 14
SP - 1
EP - 8
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-63854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
ED - Helman-Wasny, Agnieszka
T1 - The Zhangzhung Nyengyü 'Tsakalis': A Cross-Disciplinary Analysis
N2 - The publication focuses on a unique set of tsakali associated with the Zhangzhung Nyengyü cycle of Dzogchen teachings, a lineage preserved within the Kama tradition of oral transmission. Unlike Terma (Revealed Treasures), which are discovered texts often concealed for future revelation, the Zhangzhung Nyengyü has been transmitted in an unbroken line from teacher to disciple over centuries.
This study, edited by Agnieszka Helman-Ważny, represents a pioneering interdisciplinary investigation into these rare and culturally significant objects. Through the integration of textual and iconographic analysis with material science methodologies – including the examination of paper, pigments, ink and script – the work offers new perspectives on the historical and ritual functions of tsakali. This innovative approach bridges important gaps in the study of Tibetan material culture and contributes meaningfully to our broader understanding of the religious, artistic and intellectual history of Tibet and the Himalayas.
KW - Cultural heritage
KW - Manuscript cultures
KW - Tibet
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651885
SN - 978-3-11-162317-7
SN - 978-3-11-162321-4
VL - 45
SP - 1
EP - 227
PB - Walter de Gruyter GmbH
CY - Berlin
AN - OPUS4-65188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Harrab, Hayat
A1 - Askar, Enis
A1 - Franken, T.
A1 - Mauss, F.
T1 - Experimental and reaction kinetic study of hydrogen ignition behavior at ignition limits
N2 - The paper presents the results of an experimental and reaction kinetic investigation of hydrogen ignition at different pressures in a closed vessel, highlighting its non-linear behavior and the effects of radical wall termination. The reaction kinetic simulation predicts the three characteristic ignition limits of hydrogen caused by radical and thermal auto-ignition and is in close agreement with the experimental measurements. The first ignition limit is determined by the chain branching reaction H+O_2→O+ OH. This limit shows strong sensitivity towards the wall termination of O, H and OH radicals. The second ignition limit is influenced by the wall termination of O, H, OH, HO2 and H2O2 radicals. The third ignition limit is dominated by the reaction paths HO_2+HO_2→H_2 O_2+O_2 and H_2 O_2+M→2 OH+M, which is why it shows strong sensitivity towards wall termination of HO₂ and H₂O₂ radicals. Increasing the radical wall termination rate by increasing the sticking coefficient of the radicals at the wall or the surface-to-volume-ratio leads to an increase of the auto-ignition temperature at the same pressure. The introduction of radical wall termination reactions improved the prediction of ignition limits and highlighted the profound effect of the autoclave wall and vessel size on the hydrogen ignition behavior.
KW - Radical Wall Termination Reaction
KW - Hydrogen
KW - Auto-ignition Temperature
KW - Ignition Limit
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647609
DO - https://doi.org/10.1016/j.proci.2025.105980
SN - 1540-7489
VL - 41
SP - 1
EP - 7
PB - Elsevier Inc.
AN - OPUS4-64760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poliakova, A.
A1 - Ciotti, G.
A1 - Helman-Wazny, Agnieszka
A1 - Fromm, J.
T1 - Phytolith assemblages from palm leaves and palm-leaf manuscripts: what is the difference and what it could mean?
N2 - We studied freshly collected, dried and herbarized leaf fragments of two palms, namely Borassus flabellifer L. and Corypha umbraculifera L., most commonly used for palm-leaf manuscript (PLM) production in South (S) and Southeast Asia (SE) in order to reveal differences in their phytolith assemblages. For each of the two palms, 25 leaf samples were taken from the two Indian states of Kerala and Tamil Nadu. Dried leaf material was obtained from the fresh one by drying the leaves in air. Herbarium samples were obtained from two independent herbaria, specimen origin comprises S and SE Asia with the main focus on South India and Sri Lanka. Additionally, 25 manuscripts made of Borassus flabellifer leaves and 25 manuscripts made of Corypha umbraculifera leaves were investigated for phytoliths. All manuscripts are preliminary dated back to between the 16th and the beginning of the 20th century CE; most of them assumedly were produced in S India (Tamil Nadu and Kerala), Sri Lanka, Burma or Indonesia. Phytolith assemblages significantly differed between fresh, dry and herbarized palm leaves in comparison to PLM material, both qualitatively and quantitatively (mean r2 = - 0.61 ± 9.3 for Borassus samples and r2 = - 0.75 ± 5.3 for Corypha samples, at p < 0.001). Fifty-three phytolith types described for PLM material were not observed in any of the fresh, dry or herbarized palm-leaf samples. Geographical analysis of PLM-specific phytoliths suggests that the combination of those phytoliths could be region-related. In this paper, we prove that the methods of palaeoecological reconstructions based on detailed microscopy of the PLMs surface and phytolith analysis applied in combination with methods of mathematical and computer data analysis can contribute to answer the questions posed by material codicology by revealing lost manuscript production recipes and by studying manuscript provenance in terms of the geographical origin of the artefacts. Our approach can potentially open a new perspective for palaeoecological studies expanding their traditional scope and making them applicable to a new research field.
KW - Palm-leaf manuscripts
KW - Material codicology
KW - Palaeoecology
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652517
DO - https://doi.org/10.3389/fpls.2024.1482790
SN - 1664-462X
VL - 15
SP - 1
EP - 29
PB - Frontiers Media SA
AN - OPUS4-65251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Tim
A1 - Huber, Norbert
T1 - Microstructure and orientation effects on microcompression-induced plasticity in nanoporous gold
N2 - Understanding the plastic deformation of nanoporous metals requires a detailed examination of their small-scale microstructural features. In this work, we present a computational study of micropillar compression in single crystal nanoporous gold (NPG) using crystal plasticity. This approach enables a systematic investigation of three key microstructural effects, including ligament size (50 ≤ 𝑙 ≤ 400 nm), solid fraction (0.2 ≤ 𝜑 ≤ 0.3), and initial crystal orientation ([001] and [111] ̄ ), on the plastic response far beyond yielding. After validation against experimental data, the study reveals that, in line with the ’smaller is stronger’ trend, besides the yield strength, the strain hardening rate also increases as ligament size decreases. Moreover, the strain hardening rate follows a power-law scaling with solid fraction, similar to the yield strength. The analysis of two distinct crystal orientations presents findings contrasting with previous assumptions. While the yielding onset remains orientation-independent, as expected, an increase in the strain hardening rate emerges for the harder [11-1] orientation with continued compression. An effect that becomes more pronounced with increasing solid fraction and decreasing ligament size. Under these conditions, harder orientations also amplify local stress heterogeneity. Notably, the stress distribution in NPG is nearly twice as wide as that observed in the single crystal bulk material (𝜑 = 1.0). Compared to the crystal plasticity approach, traditional isotropic plasticity predicts more uniform local stress fields.
KW - Nanoporous gold
KW - Microcompression
KW - Plasticity
KW - Size effect
KW - Micromechanics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650137
DO - https://doi.org/10.1016/j.actamat.2025.121798
SN - 1359-6454
VL - 304
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-65013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rahman, Navid
A1 - Meyer, Klas
A1 - Kraus, Werner
A1 - Klapötke, Thomas M.
A1 - Witkowski, Tomasz G.
T1 - Synthesis, Characterization, and Evaluation of Energetic Properties of 1,2‐bis(5‐(Trifluoromethyl)‐4H‐1,2,4‐triazol‐3‐yl)Diazene
N2 - A new azo‐bridged compound with triazole moieties featuring trifluoromethyl groups was synthesized, exhibiting encouraging properties in the field of energetic materials. The new compound was synthesized in two steps from common starting materials using cyclocondensation, followed by oxidation reaction. The compound was characterized using nuclear magnetic resonance spectroscopy, mass spectrometry, infrared spectroscopy, and single‐crystal X‐ray diffraction. Impact and friction sensitivities were measured using BAM standard methods, and electrostatic discharge (ESD) sensitivity was measured using an ESD device from OZM Research. Heat of formation was calculated computationally using the CBS‐4m method, density was determined by the pycnometric method, and energetic properties were calculated using Explo5 software.
KW - Azo coupling
KW - Energetic material
KW - Insensitive
KW - NMR spectroscopy
KW - Triazole
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642454
DO - https://doi.org/10.1002/prep.70041
SN - 0721-3115
VL - 50
IS - 11-12
SP - 40
EP - 46
PB - Wiley-VHC
CY - Weinheim
AN - OPUS4-64245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ji, Y.
A1 - Pott, U.
A1 - Mezhov, Alexander
A1 - Rößler, Ch.
A1 - Stephan, D.
T1 - Modelling and experimental study on static yield stress evolution and structural build-up of cement paste in early stage of cement hydration
N2 - Static yield stress is crucial for concrete, especially for 3D printed concrete, as it determines whether the bottom layer can support the load of the subsequent layers or withstand any potential impulses. A better understanding of the evolution of the static yield stress and its changing mechanism is therefore needed. Under the assumption that hydrate formation follows fractal patterns, this work proposes a model for simulating static yield stress that links the hydration process and bridging possibility. To validate the model, parameters were first obtained from the BNG (Boundary Nucleation Growth) equation fitted with calorimetry data, and the relation of associated hydration rates to sound speed variation rate was analyzed. Results showed that the proposed model predicts well the static yield stress obtained with a penetration test, under varying water-cement ratios and accelerator
conditions. The fitted parameter β was found to correlate with size and morphology of the hydration products, suggesting that the model can not only simulate the static yield stress, but also capture the structural build-up information. Furthermore, the decrease in fractal-related β implies that more compact hydrates are formed during hydration.
KW - Static yield stress
KW - Fractal pattern
KW - Hydration process
KW - Bridging possibility
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623503
DO - https://doi.org/10.1016/j.cemconres.2024.107710
SN - 1873-3948
VL - 187
SP - 1
EP - 15
PB - Elsevier Ltd.
CY - Schweiz
AN - OPUS4-62350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baensch, Franziska
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
A1 - Habib, Abdel Karim
T1 - Damage evolution detection in a pipeline segment under bending by means of acoustic emission
N2 - A steel pipeline segment of 2.5 m length was subjected to quasi-static four-point bending load in three steps for studying the initial cracking and damage accumulation based on the Acoustic Emission (AE) technique and by the direct current potential drop (DCPD) technique. For the latter, a new post-test analysis method was established.
AE is found more sensitive to crack initiation than DCPD. Formation of mesoscopic and macroscopic cracks as well as their closure and the resulting friction generate weighted peak frequencies below 400 kHz, whereas microscopic cracking produces AE with broad band spectra identifiable by weighted peak frequencies above 400 kHz. Critical states alike the maximum load level and the leak opening were accompanied by peak amplitudes above 85 dBAE. This rather fundamental study provides a data base for possibly developing advanced strategies of detection and alarm systems based on acoustic monitoring of pipelines, or at least, steel structures.
KW - Crack
KW - Accoustic emission
KW - Frequency domain
KW - Potential drop technique
KW - Fracture
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565171
DO - https://doi.org/10.1016/j.ijpvp.2022.104863
SN - 0308-0161
VL - 201
IS - 104863
SP - 1
EP - 9
PB - Elsevier Science
CY - Amsterdam
AN - OPUS4-56517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kianinejad, Kaveh
A1 - Czediwoda, Fabian
A1 - Glatzel, U.
A1 - Völkl, R.
A1 - Stöhr, B.
A1 - Ávila Calderón, Luis
A1 - Schriever, Sina
A1 - Saliwan Neumann, Romeo
A1 - Fedelich, Bernard
A1 - Darvishi Kamachali, Reza
T1 - Microstructure-based modelling of the anisotropic creep behaviour in additively manufactured INCONEL 718
N2 - The existing gap in the adequate prediction of the microstructure-property relationships remains a significant barrier to the safe application of the additively manufactured materials. This challenge is fundamentally tied to the intricate microstructural defects that emerge during the processing. Systematic microstructure-based modelling can offer solutions to address this bottleneck.
In this work, we utilize a crystal plasticity model, developed for gamma''-strengthened Ni-base alloys and calibrated with single crystal tensile and creep tests of Inconel 718. By systematically refining the representative volume element complexity---from equiaxed to elongated grain morphologies, and from unimodal to bimodal orientation and grain size distributions---we demonstrate how each layer of structural realism contributes to the model’s predictive capacity.
Creep tests of laser-based powder bed fusion (PBF-LB/M) manufactured samples in three orientations (with the tensile axis parallel, perpendicular, and 45° tilted relative to the building direction) were performed at 650° C, accompanied by electron backscatter secondary diffraction measurements. The results of our simulations reveal that the bimodal grain morphology and crystallographical texture significantly influence the observed creep anisotropy. We show that the elongated grain structure combined with grain boundary sliding plays a major role in the creep response, specifically in tilted specimens.
KW - Additive manufactured Ni-base superalloys
KW - Creep Anisotropy
KW - Crystal plasticity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646884
DO - https://doi.org/10.1016/j.msea.2025.149029
VL - 945
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-64688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sobczak, M.
A1 - Lecompagnon, Julien
A1 - Hirsch, Philipp Daniel
A1 - Pieczonka, Ł.
A1 - Ziegler, Mathias
T1 - Impact damage characterization on CFRP parts using laser line scanning active thermography
N2 - This study presents a dual-path data processing framework for the detection and characterization of barely visible impact damage (BVID) in carbon-fiber-reinforced polymer (CFRP) structures using laser line thermography (LLT). A robotic LLT system was used to scan impacted CFRP specimens, and the resulting thermal sequences were analyzed using two complementary methods: full thermogram reconstruction followed by Pulse Phase Thermography (PPT) to detect subsurface delaminations, and Time-Summed Gradient Filtering (TSGF) to enhance surface-breaking cracks. Both processing paths produced interpretable results that were fused into a unified combined image and overlay mask, enabling simultaneous visualization of different defect types from a single scan. Quantitative analysis was performed on the binary masks to extract defect dimensions and Signal-to-noise ratio (SNR) values. The results demonstrated that delaminations and multiple cracks could be accurately detected and spatially distinguished, with good agreement to reference methods such as flash thermography and vibrothermography. This work highlights the potential of LLT as a versatile and scalable inspection technique, where multimodal defect detection and segmentation can be achieved through targeted processing and data fusion strategies.
KW - Active thermography
KW - CFRP
KW - Laser line scanning
KW - Delamination
KW - Cracks
KW - BVID
KW - NDT
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654097
DO - https://doi.org/10.1016/j.compositesb.2026.113425
SN - 1359-8368
VL - 313
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-65409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Nina
A1 - Uhlig, Marvin
A1 - Kromm, Arne
A1 - Schröpfer, Dirk
A1 - Höfer, Kevin
A1 - Hensel, Jonas
A1 - Kannengießer, Thomas
T1 - Challenges in the evaluation of the weldability of old mild steels for future use
N2 - For reasons of sustainability and cost efficiency, there is an increasing trend in the steel-processing industry to retrofit existing structures, avoiding costly shutdowns or dismantling. Although welding is a cost-effective joining method, it is rarely applied to old steels, whereas riveted or bolted connections are often uneconomical. Repair and refurbishment frequently require the replacement of damaged material or the creation of dissimilar old–new steel joints. Due to the varied manufacturing processes of historical steels, not all twentieth-century steels are inherently weldable, making an initial assessment of weldability
essential. In this study, a historical non-deoxidized mild steel (produced by Siemens–Martin processing) originating from the construction of the Berlin Radio Tower (erected in 1926) was investigated using dilatometry to analyze its welding behavior. A database of welding CCT diagrams and HAZ simulations was established to support practice-oriented welding experiments, providing key insights into their weld-metallurgical behavior and weldability. Furthermore, initial welding trials were conducted, and the local residual stress states in dissimilar old–new steel joints were determined. These foundational investigations are critical for the development of innovative, load-adapted welding concepts for the repair and refurbishment of existing old-steel infrastructure in Germany.
KW - Old mild steels
KW - Repair welding
KW - Weldability
KW - Thermo-physical simulation
KW - CCT diagrams
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654784
DO - https://doi.org/10.1007/s40194-026-02366-6
SN - 1878-6669
SP - 1
EP - 14
PB - Springer nature
AN - OPUS4-65478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spitzer, Stefan
A1 - Amyotte, P.
A1 - Salzano, E.
T1 - Explosion behavior of hybrid mixtures
N2 - Flammable mixtures of dusts with gases or liquids occur in the process and energy industries. Most research about these so-called "hybrid mixtures" was, and still is, about coal dust with the admixture of methane because of their occurrence in the mining industry. In the modern industry, hybrid mixture explosions play an increasing role in many existing processes like spray-drying, or in emerging technologies like the direct reduction of iron ore with hydrogen or nuclear/fusion reactors. While some safety characteristics of one of the component substances stay the same or are unaffected by the concentrations that occur in the process, others are severely influenced by only traces of the other substance.
This review paper shows in which processes and applications hybrid mixtures pose a risk and gives an overview of the research conducted in the last 150 years. Findings that are reproducible and represent current proven knowledge are stated and compared to each safety characteristic containing only solid particles, gases or liquids as combustible substances. Additionally, fundamental studies on the mechanisms of flame propagation in hybrid mixtures are reviewed. The significance of these studies in enhancing our understanding of explosion behaviors in hybrid mixtures is also discussed. An outlook on what has been missing so far in the literature, is also given comparing the knowledge of single substances with their mixtures, why this might not have been investigated, and where the challenges lie.
KW - Hybrid mixtures
KW - Safety characteristics
KW - Combustion regimes
KW - Industrial explosions
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654013
DO - https://doi.org/10.1016/j.pecs.2025.101276
SN - 0360-1285
VL - 113
SP - 1
EP - 24
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oskoei, Párástu
A1 - Afonso, Rúben
A1 - Bastos, Verónica
A1 - Nogueira, João
A1 - Keller, Lisa-Marie
A1 - Andresen, Elina
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Daniel-da-Silva, Ana L.
A1 - Oliveira, Helena
T1 - Upconversion Nanoparticles with Mesoporous Silica Coatings for Doxorubicin Targeted Delivery to Melanoma Cells
N2 - Melanoma is one of the most aggressive skin cancers and requires innovative therapeutic strategies to overcome the limitations of conventional therapies. In this work, upconversion nanoparticles coated with mesoporous silica and functionalized with folic acid (UCNP@mSiO2-FA) were developed as a targeted nanocarrier system for the delivery of doxorubicin (DOX). The UCNPs were synthesized via thermal decomposition, coated with mesoporous silica shells, and functionalized with folic acid (FA) to enable receptor-mediated targeting. DOX was then loaded into the mesoporous silica coating by adsorption, yielding UCNP@mSiO2-FA-DOX. The different UCNPs were characterized for size, composition, colloidal stability, and loading and release of DOX. This comprehensive physicochemical characterization confirmed a high DOX loading efficiency and a slightly increased drug release under acidic conditions, mimicking the tumour microenvironment. In vitro assays using four melanoma cell lines (A375, B16-F10, MNT-1, and SK-MEL-28) revealed an excellent biocompatibility of UCNP@mSiO2-FA and a significantly higher cytotoxicity of UCNP@mSiO2-FA-DOX compared to unloaded UCNPs, in a dose-dependent manner. Cell cycle analysis demonstrated G2/M phase arrest after treatment with UCNP@mSiO2-FA-DOX, confirming its antiproliferative effect. Overall, UCNP@mSiO2-FA-DOX represents a promising nanoplatform for targeted melanoma therapy, combining active tumour targeting and enhanced anticancer efficacy.
KW - Fluorescence
KW - Synthesis
KW - Nano
KW - Particle
KW - Silica
KW - Cell
KW - Uptake
KW - Drug
KW - Characterization
KW - DOX
KW - Imaging
KW - Toxicity
KW - Release
KW - pH
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653596
DO - https://doi.org/10.3390/molecules31010074
SN - 1420-3049
VL - 31
IS - 1
SP - 1
EP - 18
PB - MDPI AG
AN - OPUS4-65359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Smales, Glen Jacob
A1 - Seitz, H.
A1 - Solomun, Tihomir
A1 - Sturm, Heinz
T1 - Ectoine interaction with DNA: Influence on ultraviolet radiation damage
N2 - Ectoine is a small zwitterionic osmolyte and compatible solute, which does not interfere with cell metabolism even at molar concentrations. Plasmid DNA (pUC19) was irradiated with ultraviolet radiation (UV-C at 266 nm) under quasi physiological conditions (PBS) and in pure water in the presence and absence of ectoine (THP(B)) and hydroxyectoine (THP(A)). Different types of UV induced DNA damage were analysed: DNA single-strand breaks (SSBs), abasic sites and cyclobutane pyrimidine dimers (CPDs). A complex interplay between these factors was observed with respect to the nature and occurrence of DNA damage with 266 nm photons. In PBS, the cosolutes showed efficient protection against base damage, whilst in pure water, a dramatic shift from SSB damage to base damage was observed when cosolutes were added. To test whether these effects are caused by ectoine binding to DNA, further experiments were conducted: small-angle X-ray scattering (SAXS), surface-plasmon resonance (SPR) measurements and Raman spectroscopy. The results show, for the first time, a close interaction between ectoine and DNA. This is in stark contrast to the assumption made by preferential exclusion models, which are often used to interpret the behaviour of compatible solutes within cells and with biomolecules. It is tentatively proposed that the alterations of UV damage to DNA are attributed to ectoine influence on nucleobases through the direct interaction between ectoine and DNA.
KW - Ectoine
KW - DNA
KW - Radiation damage
KW - Radiation protection
KW - SSB
KW - DNA damage
KW - DNA protection
KW - Compatible solute
KW - Zwitterion
KW - Hydroxyectoine
KW - Salt
KW - PBS
KW - UV absorption
KW - DNA strand-break
KW - DNA base damage
KW - Ectoine UV absorption
KW - Ectoine DNA protection
KW - Excited states
KW - UV irradiation
KW - UV-A
KW - UV-B
KW - UV-C
KW - 266nm
KW - UV photons
KW - Ectoine-DNA binding
KW - Raman spectroscopy
KW - UV-Vis
KW - Radical scavenger
KW - OH scavenger
KW - Hydroxyl radicals
KW - CPD
KW - Abasic site
KW - Agarose gel electrophorese
KW - SYBR gold
KW - DNA melting temperature
KW - Counterions
KW - Preferential exclusion
KW - Cancer
KW - Therapy
KW - UV protection
KW - Sunscreen
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505772
DO - https://doi.org/10.1039/d0cp00092b
SN - 1463-9076
SN - 1463-9084
VL - 22
IS - 13
SP - 6984
EP - 6992
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-50577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Solomun, Tihomir
A1 - Hahn, Marc Benjamin
A1 - Smiatek, J.
T1 - Raman spectroscopic signature of ectoine conformations in bulk solution and crystalline state
N2 - Recent crystallographic results revealed conformational changes of zwitterionic ectoine upon hydration. By means of confocal Raman spectroscopy and density functional theory calculations, we present a detailed study of this transformation process as part of a Fermi resonance analysis. The corresponding findings highlight that all resonant couplings are lifted upon exposure to water vapor as a consequence of molecular binding processes. The importance of the involved molecular groups for water binding and conformational changes upon hydration is discussed. Our approach further Shows that the underlying rapid process can be reversed by carbon dioxide saturated atmospheres. For the first time, we also confirm that the conformational state of ectoine in aqueous bulk solution coincides with crystalline ectoine in its dihydrate state, thereby highlighting the important role of a few bound water molecules.
KW - Fermi resonance
KW - Ectoine hydration
KW - DFT calculations of Raman spectra
KW - Position of carboxylate group
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509855
DO - https://doi.org/10.1002/cphc.202000457
SN - 1439-4235
SN - 1439-7641
VL - 21
IS - 17
SP - 1945
EP - 1950
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-50985
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodriguez, Santiago
A1 - Kumanski, Sylvain
A1 - Ayed, Zeineb
A1 - Fournet, Aurélie
A1 - Bouanchaud, Charlène
A1 - Sagar, Amin
A1 - Allemand, Frédéric
A1 - Baulin, Vladimir A.
A1 - Resch‐Genger, Ute
A1 - Cortés, Juan
A1 - Sibille, Nathalie
A1 - Chirot, Fabien
A1 - Wegner, Karl David
A1 - Antoine, Rodolphe
A1 - Le Guével, Xavier
A1 - Bernadó, Pau
T1 - Programming the Optoelectronic Properties of Atomically Precise Gold Nanoclusters Using the Conformational Landscape of Intrinsically Disordered Proteins
N2 - The rational design of hybrid nanomaterials with precisely controlled properties remains a central challenge in materials science. While atomically precise gold nanoclusters (Au‐NCs) offer molecule‐like control over a metallic core, tuning their optoelectronic behavior via surface engineering is often empirically driven. Here, we establish a design principle by demonstrating that the conformational landscape of intrinsically disordered proteins (IDP) can be used as a programmable scaffold to rationally modulate the photophysical properties of a covalently bound Au‐NC. We synthesized a series of bioconjugates between Au 25 nanoclusters and bioengineered IDPs containing a variable number of cysteine anchoring points. A combination of mass spectrometry, small‐angle X‐ray scattering, and modeling on the conjugates indicates that increasing the number of covalent anchors systematically restricts the conformational ensemble, inducing a progressively more compact protein shell around nanoclusters. This structural rigidification at the interface directly translates into a 15‐fold enhancement of the Au‐NC near‐infrared photoluminescence and a six‐fold increase in its average lifetime. Our findings demonstrate that the conformational plasticity of IDPs and the capacity to engineer them can be harnessed as a molecular tuning knob, moving to a new regime of programmable soft‐matter control over the properties of quantum‐confined nanomaterials for tailored biotechnological applications.
KW - Fluorescence
KW - Custer
KW - Nano
KW - Advanced material
KW - Characterization
KW - Fluorescence quantum yield
KW - Integrating sphere spectroscopy
KW - Thiol ligands
KW - Gold
KW - Surface chemistry
KW - SWIR
KW - Mass spectrometry
KW - Protein
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655086
DO - https://doi.org/10.1002/chem.202502991
SN - 0947-6539
SP - 1
EP - 9
PB - Wiley VHC-Verlag
AN - OPUS4-65508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rastgou, Masoud
A1 - Hülagü, Deniz
A1 - Danilenko, Aleksandr
A1 - Manoocheri, Farshid
A1 - Hertwig, Andreas
A1 - Ikonen, Erkki
T1 - Comparison of thin-film thickness measurements using ellipsometry and reflectometry with uniform samples
N2 - This study evaluates spectroscopic ellipsometry and reflectometry using high-quality SiO2 and Al2O3 thin-films on Si substrates, thereby facilitating a detailed assessment of consistency of measurement results and uncertainty analyses. The results with detailed uncertainty budgets indicate good agreement between the two methods across a broad layer thickness range from 10 nm to 2000 nm, with deviations remaining well within the measurement uncertainties. Ellipsometry results have lower uncertainty than reflectometry results especially with the thinner layers, whereas reflectometry uncertainties are lower with the thickest layers studied. This work underscores the importance of rigorous thickness characterization and reliable uncertainty evaluation as critical factors in advancing both modeling and measurement practices in thin-film metrology.
KW - Ellipsometry
KW - Reflectometry
KW - Thin Film Metrology
KW - Measurement Accuracy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655209
DO - https://doi.org/10.1088/1681-7575/ae3964
SN - 0026-1394
VL - 63
IS - 1
SP - 1
EP - 14
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-65520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernardy, Christopher
A1 - Habib, Abdel Karim
A1 - zur Nedden, Philipp Maximilian
A1 - von Saldern, Jakob Georg Raimund
A1 - Beuth, Jan Paul
A1 - Orchini, Alessandro
T1 - Thermal Radiation Of Inclined Large Scale Hydrogen Jet Flames
N2 - In order to assess the thermal radiation emanating from hydrogen jet flames, experiments under real scale conditions were carried out at the Test Site Technical Safety of BAM. Herein, the behavior of inclined hydrogen jet flames was investigated. The aim of the work is to determine the Surface Emissive Power (SEP) and radiant heat fraction of these flames and to provide a reliable dataset for model evaluation purposes. Since the aforementioned values are not directly measurable, the incident heat radiation was measured at defined distances from the flame, as well as the flame’s shape and size. The required values were then derived from these measurements. The hydrogen releases ranged from 0.0125 kg/s to 0.175 kg/s with a 30 mm orifice. The mass flows were held constant during the releases, nevertheless a transient behavior of the flame could be observed since the experiments were carried out under open field conditions, with unsteady wind fields. In the literature, the flame lengths are often determined using visible light imaging, either by injecting coloring substances in the low light emitting hydrogen jet flame or by carrying out the measurements in darkness. In this work the jet flames were visualized using infrared (IR) and OH* imaging. The recorded flame shapes and resulting flame lengths are compared. Results from this showed that the flame lengths determined with OH* and IR recordings differ greatly. A flame length ratio lf OH*/lf IR in the range of 0.47–0.62 can be found. In addition, the SEP differ also in the range of 10 kW/m2–16 kW/m2 (IR) and 40 kW/m2–80 kW/m2 (OH*) for hydrogen jet flames due to differences in the determined flame surface. Conclusions regarding the determined xRAD values for IR and OH* result in approximately the same range of 0.031–0.043.
T2 - 11th Iinternational conference on hydrogen safety 2025
CY - Seoul, Republic of Korea
DA - 22.09.2025
KW - Hydrogen safety
KW - Jet flames
KW - Thermal radiation
KW - Large scale experiment
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655181
DO - https://doi.org/10.58895/hysafe.27
SN - 2943-5935
VL - 3
IS - 1
SP - 39
EP - 50
PB - Karlsruhe Institute of Technology Library
AN - OPUS4-65518
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herzel, Hannes
A1 - Dombinov, V.
A1 - Vogel, Christian
A1 - Willbold, S.
A1 - Levandowski, G. V.
A1 - Meiller, M.
A1 - Müller, F.
A1 - Zang, J. W.
A1 - da Fonseca-Zang, W. A.
A1 - Jablonowski, N. D.
A1 - Schrey, S. D.
A1 - Adam, Christian
T1 - Soybean Fertilized by P-Phases from Bagasse-Based Materials: P-Extraction Procedures, Diffusive Gradients in Thin Films (DGT), and X-ray Diffraction Analysis (XRD)
N2 - The Brazilian sugarcane industry produced around 173 million tons (Mt) of bagasse in 2018. Bagasse is a by-product of juice extraction for ethanol and sugar production and is combusted in order to generate power, producing up to 10 Mt of ash per year. This ash contains various concentrations of plant nutrients, which allow the ash to be used as a crop fertilizer. However, the concentration and extractability of phosphorus (P), an essential plant nutrient, are low in bagasse ash. To increase the P content, we co-gasified and co-combusted bagasse with P-rich chicken manure. The resulting ash was thermochemically post-treated with alkali additives (Na2SO4 and K2SO4) to increase the availability of P to plants. We aimed to: (i) investigate the effect of thermochemical post-treatment of co-gasification residue and co-combustion ash on P availability to soybeans, (ii) explore the potential of chemical extraction methods (citric acid, neutral ammonium citrate, formic acid, and Mehlich-I) and diffusive gradients in thin films (DGT) to predict the availability of P to soybeans, and (iii) identify the responsible P-phases using X-ray diffraction . We evaluated P availability to soybeans growing in Brazilian Oxisol soil in two independent greenhouse pot experiments. The positive effect of thermochemical treatment on P availability from gasification residue was confirmed through the observation of increased P uptake and biomass in soybean plants. These findings were confirmed by chemical extraction methods and DGT. The gasification residue contained whitlockite as its main P-bearing phase. Thermochemical post-treatment converted whitlockite into highly soluble CaNaPO4. In contrast, co-combustion ash already contained highly soluble Ca(Na,K)PO4 as its main P-bearing phase, making thermochemical post-treatment unnecessary for increasing P availability. In conclusion, increased extractability and availability of P for soybeans were closely connected to the formation of calcium alkali phosphate. Our findings indicate that this combined methodology allows for the prediction of P-fertilization effects of ash.
KW - Sugar cane bagasse
KW - Chicken manure ash
KW - Thermochemical treatment
KW - Nutrient
KW - Plant availability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509735
DO - https://doi.org/10.3390/agronomy10060895
VL - 10
SP - 895
EP - 6
PB - MDPI
AN - OPUS4-50973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stohl, Leonie
A1 - Manninger, Tanja
A1 - von Werder, Julia
A1 - Dehn, F.
A1 - Gorbushina, Anna
A1 - Meng, Birgit
T1 - Bioreceptivity of concrete - A review
N2 - Materials that support natural biodiversity on their surfaces can compensate for human activities that have a negative impact on nature and thus contribute to a carbon-neutral and nature-positive world. Specifically designing bioreceptive materials which favor the growth of biofilms on their surface is an approach complementing conventional, macroscopic green façades. But what exactly characterizes a bioreceptive substrate and how do biofilm and substrate interact? How and why does a spontaneous colonization and the formation of biofilms take place? What are biofilms and how can they be established in a laboratory setting? How can this existing knowledge be transferred to the artificial stone concrete so that this material can be tuned to increase (or decrease) its bioreceptivity?
This review paper aims at summarizing the existing state of knowledge on bioreceptive concrete and pointing out inconsistencies and contradictions which can only be removed by more interdisciplinary research in the field.
KW - Bioreceptivity
KW - Biofilm
KW - Green facades
KW - Developing building materials
KW - Surface interactions
KW - Concrete
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581685
DO - https://doi.org/10.1016/j.jobe.2023.107201
SN - 2352-7102
VL - 76
SP - 1
EP - 17
PB - Elsevier
AN - OPUS4-58168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zocca, Andrea
A1 - Wilbig, Janka
A1 - Waske, Anja
A1 - Günster, Jens
A1 - Widjaja, Martinus Putra
A1 - Neumann, C.
A1 - Clozel, M.
A1 - Meyer, A.
A1 - Ding, J.
A1 - Zhou, Z.
A1 - Tian, X.
T1 - Challenges in the Technology Development for Additive Manufacturing in Space
N2 - Instead of foreseeing and preparing for all possible scenarios of machine failures, accidents, and other challenges arising in space missions, it appears logical to take advantage of the flexibility of additive manufacturing for “in-space manufacturing” (ISM). Manned missions into space rely on complicated equipment, and their safe operation is a great challenge. Bearing in mind the absolute distance for manned missions to the Moon and Mars, the supply of spare parts for the repair and replacement of lost equipment via shipment from Earth would require too much time. With the high flexibility in design and the ability to manufacture ready-to-use components directly from a computer-aided model, additive manufacturing technologies appear to be extremely attractive in this context. Moreover, appropriate technologies are required for the manufacture of building habitats for extended stays of astronauts on the Moon and Mars, as well as material/feedstock. The capacities for sending equipment and material into space are not only very limited and costly, but also raise concerns regarding environmental issues on Earth. Accordingly, not all materials can be sent from Earth, and strategies for the use of in-situ resources, i.e., in-situ resource utilization (ISRU), are being
envisioned. For the manufacturing of both complex parts and equipment, as well as for large infrastructure, appropriate technologies for material processing in space need to be developed.
KW - Additive manufacturing
KW - Space
KW - Process
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549204
DO - https://doi.org/10.1016/j.cjmeam.2022.100018
SN - 2772-6657
VL - 1
IS - 1
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-54920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Vallée, A.
A1 - Bally, P.
A1 - Bruel, C.
A1 - Chandat, L.
A1 - Choquer, M.
A1 - Dieryckx, C.
A1 - Dupuy, J.W.
A1 - Kaiser, S.
A1 - Latorse, M.-P.
A1 - Loisel, E.
A1 - Mey, G.
A1 - Morgant, G.
A1 - Rascle, C.
A1 - Schumacher, Julia
A1 - Simon, A.
A1 - Souibgui, E.
A1 - Viaud, M.
A1 - Villalba, F.
A1 - Poussereau, N.
T1 - A similar secretome disturbance as a hallmark of non-pathogenic Botrytis cinerea ATMT-mutants?
N2 - The gray mold fungus Botrytis cinerea is a necrotrophic pathogen able to infect
hundreds of host plants, including high-value crops such as grapevine, strawberry and tomato. In order to decipher its infectious strategy, a library of 2,144 mutants was generated by random insertional mutagenesis using Agrobacterium tumefaciensmediated transformation (ATMT). Twelve mutants exhibiting total loss of virulence toward different host plants were chosen for detailed analyses. Their molecular characterization revealed a single T-DNA insertion in different loci. Using a proteomics approach, the secretome of four of these strains was compared to that of the parental strain and a common profile of reduced lytic enzymes was recorded. Significant variations in this profile, notably deficiencies in the secretion of proteases and hemicellulases, were observed and validated by biochemical tests. They were also a hallmark of the remaining eight non-pathogenic strains, suggesting the importance of these secreted Proteins in the infection process. In the twelve non-pathogenic mutants, the Differentiation of infection cushions was also impaired, suggesting a link between the Penetration structures and the secretion of proteins involved in the virulence of the pathogen.
KW - Fungus
KW - Plant pathogen
KW - Virulence
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502710
DO - https://doi.org/10.3389/fmicb.2019.02829
SN - 1664-302X
VL - 10
SP - Article 2829
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-50271
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neumann, Christian
A1 - Thore, Johannes
A1 - Clozel, Mélanie
A1 - Günster, Jens
A1 - Wilbig, Janka
A1 - Meyer, Andreas
T1 - Additive manufacturing of metallic glass from powder in space
N2 - Additive manufacturing of metals – and in particular building with laser-based powder bed fusion – is highly flexible and allows high-resolution features and feedstock savings. Meanwhile, though space stations in low Earth orbit are established, a set of visits to the Moon have been performed, and humankind can send out rovers to explore Venus and Mars, none of these milestone missions is equipped with technology to manufacture functional metallic parts or tools in space. In order to advance space exploration to long-term missions beyond low Earth orbit, it will be crucial to develop and employ technology for in-space manufacturing (ISM) and in-situ resource utilisation (ISRU). To use the advantages of laser-based powder bed fusion in these endeavours, the challenge of powder handling in microgravity must be met. Here we present a device capable of building parts using metallic powders in microgravity. This was proven on several sounding rocket flights, on which occasions Zr-based metallic glass parts produced by additive manufacturing in space were built. The findings of this work demonstrate that building parts using powder feedstock, which is more compact to transport into space than wire, is possible in microgravity environments. This thus significantly advances ISRU and ISM and paves the way for future tests in prolonged microgravity settings.
KW - Metallic Glass
KW - Additive Manufacturing
KW - Space
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600667
DO - https://doi.org/10.1038/s41526-023-00327-7
VL - 9
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-60066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stohl, Leonie
A1 - Tonon, Chiara
A1 - Cook, Jake
A1 - Gorbushina, Anna
A1 - Dehn, Frank
A1 - von Werder, Julia
T1 - Understanding bioreceptivity of concrete: realistic and accelerated weathering experiments with model subaerial biofilms
N2 - Vertical greening systems are a promising solution to the increasing demand for urban green spaces, improving environmental quality and addressing biodiversity loss. This study facilitates the development microbially greened algal biofilm facades, which offer a low maintenance vertical green space. The study focuses on concrete as a widely used building material and explores how physical surface characteristics impact its bioreceptive properties. Concrete samples, produced from the same mix but differing in surface structure, were subjected to a laboratory weathering experiment to assess their bioreceptivity. A novel inoculation method was employed, involving a single initial inoculation with either alga ( Jaagichlorella sp.) alone, or a model biofilm consisting of a combination of the alga ( Jaagichlorella sp.) with a fungus ( Knufia petricola). The samples underwent four months of weathering in a dynamic laboratory setup irrigated with deionized water to observe subaerial biofilm attachment and growth. The formation of subaerial biofilms was monitored with high resolution surface imaging, colorimetric measurements and Imaging Pulse Amplitude Modulated Fluorometry (Imaging PAM-F), with Imaging PAM-F proving the most effective. Statistical analysis revealed that by impacting surface pH value and water retention capability, surface structures significantly influence microbial growth and that the concrete’s bioreceptivity can be influenced through thoughtful design of the materials surface. The inoculation of algae combined with a fungus facilitated the formation of a stable subaerial biofilm, enabling algae to colonize a surface structure that it could not colonize alone. This finding highlights the importance of modelling synergistic interactions present in natural biofilms.
KW - Bioreceptivity
KW - Concrete
KW - Biofilm
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653105
DO - https://doi.org/10.1617/s11527-025-02864-x
SN - 1359-5997
VL - 59
IS - 2
SP - 1
EP - 18
PB - Springer Science and Business Media LLC
AN - OPUS4-65310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diener, S.
A1 - Schubert, Hendrik
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Ink development for the additive manufacturing of strong green parts by layerwise slurry deposition (LSD-print)
N2 - Obtaining dense fine ceramics by the binder jetting additive manufacturing process is challenging. A slurry-based binder jetting process, such as the layerwise slurry deposition (LSD-print) process, can enable the printing of dense ceramic parts. This work describes a procedure to develop and qualify a suitable ink to manufacture silicon carbide green parts by LSD-print. Not only the printability but also the compatibility of the ink with the powder bed and the effect of the binding agent on the properties of the green parts are considered. Both aspects are important to obtain high green strength, which is necessary for printing large or thin-walled parts. Characterization methods, such as rheological and surface tension measurements, are applied to optimize three selected inks. The interplay between ink and powder bed is tested by contact angle measurements and by comparing the biaxial strength of cast and additively manufactured specimens.
Out of the three binding agents tested, a polyethyleneimine and a phenolic resin have a high potential for their use in the LSD-print of silicon carbide green bodies, whereas a polyacrylate binding agent did not show the required properties.
KW - Silicon carbide
KW - Binders/binding
KW - Inkjet
KW - Printing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567911
DO - https://doi.org/10.1111/jace.18951
SN - 0002-7820
SP - 1
EP - 12
PB - Wiley online library
AN - OPUS4-56791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fornacon-Wood, Christoph
A1 - Stühler, Merlin R.
A1 - Millanvois, Alexandre
A1 - Steiner, Luca
A1 - Weimann, Christiane
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
A1 - Paulus, Beate
A1 - Plajer, Alex J.
T1 - Fluoride recovery in degradable fluorinated polyesters
N2 - We report a new class of degradable fluorinated polymers through
the copolymerization of tetrafluorophthalic anhydride and propylene
oxide or trifluoropropylene oxide which show up to 20 times
quicker degradation than the non-fluorinated equivalents and allow
for fluoride recovery.
KW - Fluoropolymers
KW - Recycling
KW - PFAS
KW - AFM force distance curves
KW - AFM plastic deformation
KW - AFM friction analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606768
DO - https://doi.org/10.1039/d4cc02513j
VL - 60
SP - 7479
EP - 7482
PB - Royal Society of Chemistry
AN - OPUS4-60676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, Joachim
A1 - Adamczyk, Burkart
A1 - Ebert, D.
A1 - Ehrenberg, A.
A1 - Schraut, Katharina
A1 - Gerlach, J.
A1 - Wendt, K.
A1 - Algermissen, D.
A1 - Adam, Christian
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Erzeugung von Bindemitteln aus Stahlwerksschlacken
N2 - Die geplante Transformation der Stahlindustrie innerhalb der nächsten 20 Jahre hat aufgrund des mit ihr verbundenen Auslaufens der Hüttensanderzeugung Konsequenzen für die Zementindustrie, deren Abmilderung Gegenstand der Forschungsprojekte SlagCEM und DRI-EOS ist. Ersteres untersucht die Rückgewinnung von Eisen aus LD-Konverter-Schlacke bei gleichzeitiger Herstellung eines mineralischen Produktes mit zementä- ren Eigenschaften. Zweiteres befasst sich mit der Generierung eines Hüttensandersatzes aus Lichtbogen- ofenschlacke mit Rückgewinnung von Schwermetallen sowie deren Umwelteffekt bei Verbleib in der Schlacke.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Bindemittel
KW - Stahlwerksschlacke
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613127
SN - 978-3-9818564-7-7
SP - 78
EP - 89
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61312
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmed, A. A. A.
A1 - Alegret, N.
A1 - Almeida, B.
A1 - Alvarez-Puebla, R.
A1 - Andrews, A. M.
A1 - Ballerini, L.
A1 - Barrios-Capuchino, J. J.
A1 - Becker, C.
A1 - Blick, R. H.
A1 - Bonakdar, S.
A1 - Chakraborty, I.
A1 - Chen, X.
A1 - Cheon, J.
A1 - Chilla, G.
A1 - Conceicao, A. L. C.
A1 - Delehanty, J.
A1 - Dulle, M.
A1 - Efros, A. L.
A1 - Epple, M.
A1 - Fedyk, M.
A1 - Feliu, N.
A1 - Feng, M.
A1 - Fernandez-Chacon, R.
A1 - Fernandez-Cuesta, I.
A1 - Fertig, N.
A1 - Förster, S.
A1 - Garrido, J. A.
A1 - George, M.
A1 - Guse, A. H.
A1 - Hampp, N.
A1 - Harberts, J.
A1 - Han, J.
A1 - Heekeren, H. R.
A1 - Hofmann, U. G.
A1 - Holzapfel, M.
A1 - Hosseinkazemi, H.
A1 - Huang, Y.
A1 - Huber, P.
A1 - Hyeon, T.
A1 - Ingebrandt, S.
A1 - Ienca, M.
A1 - Iske, A.
A1 - Kang, Y.
A1 - Kasieczka, G.
A1 - Kim, D.-H.
A1 - Kostarelos, K.
A1 - Lee, J.-H.
A1 - Lin, K.-W.
A1 - Liu, S.
A1 - Liu, X.
A1 - Liu, Y.
A1 - Lohr, C.
A1 - Mailänder, V.
A1 - Maffongelli, L.
A1 - Megahed, S.
A1 - Mews, A.
A1 - Mutas, M.
A1 - Nack, L.
A1 - Nakatsuka, N.
A1 - Oertner, T. G.
A1 - Offenhäusser, A.
A1 - Oheim, M.
A1 - Otange, B.
A1 - Otto, F.
A1 - Patrono, E.
A1 - Peng, B.
A1 - Picchiotti, A.
A1 - Pierini, F.
A1 - Pötter-Nerger, M.
A1 - Pozzi, M.
A1 - Pralle, A.
A1 - Prato, M.
A1 - Qi, B.
A1 - Ramos-Cabrer, P.
A1 - Resch-Genger, Ute
A1 - Ritter, N.
A1 - Rittner, M.
A1 - Roy, S.
A1 - Santoro, F.
A1 - Schuck, N. W.
A1 - Schulz, F.
A1 - Seker, E.
A1 - Skiba, M.
A1 - Sosniok, M.
A1 - Stephan, H.
A1 - Wang, R.
A1 - Wang, T.
A1 - Wegner, Karl David
A1 - Weiss, P. S.
A1 - Xu, M.
A1 - Yang, C.
A1 - Zargarin, S. S.
A1 - Zeng, Y.
A1 - Zhou, Y.
A1 - Zhu, D.
A1 - Zierold, R.
A1 - Parak, W. J.
T1 - Interfacing with the Brain: How Nanotechnology Can Contribute
N2 - Interfacing artificial devices with the human brain is the central goal of neurotechnology. Yet, our imaginations are often limited by currently available paradigms and technologies. Suggestions for brain−machine interfaces have changed over time, along with the available technology.
Mechanical levers and cable winches were used to move parts of the brain during the mechanical age. Sophisticated electronic wiring and remote control have arisen during the electronic age, ultimately leading to plug-and-play computer interfaces. Nonetheless, our brains are so complex that these visions, until recently, largely remained unreachable dreams. The general problem, thus far, is that most of our technology is mechanically and/or electrically engineered, whereas the brain is a living, dynamic entity. As a result, these worlds are difficult to interface with one another. Nanotechnology, which encompasses engineered solid-state objects and integrated circuits, excels at small length scales of single to a few hundred nanometers and, thus, matches the sizes of biomolecules, biomolecular assemblies, and parts of cells. Consequently, we envision nanomaterials and nanotools as opportunities to interface with the brain in alternative ways. Here, we review the existing literature on the use of nanotechnology in brain−machine interfaces and look forward in discussing perspectives and limitations based on the authors’ expertise across a range of complementary disciplines from neuroscience, engineering, physics, and chemistry to biology and medicine, computer science and mathematics, and social science and jurisprudence. We focus on nanotechnology but also include information from related fields when useful and complementary.
KW - Nanoneuro interface
KW - Brain-on-a-chip
KW - Nanostructured interface
KW - Electrode arrays
KW - Neuro-implants
KW - Advanced nanomaterials
KW - Quality assurance
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634893
DO - https://doi.org/10.1021/acsnano.4c10525
SN - 1936-086X
VL - 19
IS - 11
SP - 10630
EP - 10717
PB - ACS Publications
AN - OPUS4-63489
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Walsh, Michael
A1 - Schenk, Gerhard
A1 - Robinson, Nicole
A1 - John, Samuel
A1 - Dayananda, Buddhi
A1 - Krishnan, Vithya
A1 - Adam, Christian
A1 - Hermann, Ludwig
A1 - Schmidt, Susanne
T1 - The Circular Phosphorus Economy: Agronomic Performance of Recycled Fertilizers and Target Crops
N2 - ABSTRACTBackgroundThe circular phosphorus (P) economy addresses economic and environmental penalties inherent to the current linear P economy. Phosphorus sources recovered from waste steams (recyclates) offer an alternative to conventional fertilizers.AimThis research aimed to assess the agronomic performance of P recyclates derived from wastewater (hazenite, struvite), treated sewage sludge ash (SSA) and compost (FOGO food organics/garden organics) with crops previously characterized for P use efficiency (PUE).MethodsPhosphorus was supplied as granules and benchmarked against conventional fertilizers or mineral solution. Grown in controlled conditions, crops received recyclates individually or as amalgamates, with or without additional water‐soluble P. We quantified P uptake, yield and phytate content, and calculated agronomic performance indicators.ResultsResults revealed that (1) crop genotypes with purportedly lower or higher PUE showed similar performance when grown with limiting P supply and/or less soluble P recyclates, (2) crop performance improved when less soluble P recyclates were combined with water‐soluble P, (3) crops produced similar yield and biomass when supplied with an organo‐mineral formulation, hazenite, or conventional fertilizer, (4) grain accumulated higher levels of the antinutrient phytate with excess soluble P.ConclusionWe conclude that suitably formulated P recyclates can supplement or replace conventional fertilizers, and that fertilizer design should consider the solubility of recyclates and a crop's ability to access less soluble P. This adds to the growing body of evidence that well‐formulated next‐generation fertilizers can efficiently nourish crops. Integrating insights from controlled experiments and field trials is a cost‐effective strategy to actualize the circular P economy.
KW - Recycling fertilizer
KW - Phosphate recovery
KW - Sewage sludge ash
KW - Struvite
KW - Hazenite
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627116
DO - https://doi.org/10.1002/jpln.202400299
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-62711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stephan, Jenny
A1 - Stühler, Merlin R.
A1 - Fornacon-Wood, Christoph
A1 - Dimde, Mathias
A1 - Ludwig, Kai
A1 - Sturm, Heinz
A1 - Olmedo-Martínez, Jorge L.
A1 - Müller, Alejandro J.
A1 - Plajer, Alex J.
T1 - Sulfur-containing block polymers from ring-opening copolymerization: coordinative encapsulants for transition metals
N2 - Sulfur-containing polymers can coordinate transition metals via sulfur-centered, chemically soft lone pairs, although this typically occurs in a spatially uncontrolled manner. In this study, we employed the controlled ring-opening copolymerization of oxetane with sulfur-containing comonomers to construct a series of amphiphilic block copolymers featuring thioester and thiocarbonate functionalities. These copolymers self-assemble in aqueous solution into aggregates with a sulfur-rich core capable of coordinating transition metals. This behavior could be resolved by employing cryo-transmission electron tomography and then extended to complexes incorporating functional coligands. Our study demonstrates how selective catalysis can be harnessed to produce functional polymers with tunable metal coordination properties, paving the way for an emerging class of sulfur-containing copolymers.
KW - Sulfur-containing polymer
KW - Controlled synthesis
KW - Metal ion coordination
KW - Cryo TEM
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626157
DO - https://doi.org/10.1039/d4py01415d
SN - 1759-9962
VL - 16
IS - 8
SP - 1003
EP - 1009
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62615
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Dahshan, O.
A1 - Deniaud, A.
A1 - Ling, W. L.
A1 - Wegner, Karl David
A1 - Proux, O.
A1 - Veronesi, G.
A1 - Reiss, P.
T1 - Hydrothermal microwave synthesis of water soluble NIR-II emitting Ag2S quantum dots
N2 - Hydrothermal-based synthetic methods of quantum dots allow for the exploration of reaction parameters normally inaccessible to typical aqueous-based batch reactions, such as elevated reaction temperatures (>100 °C) and reaction pressures above atmospheric pressure. Coupled with microwave heating, new instantaneously bio-compatible quantum dots (QDs) with enhanced opitcal properties can be yielded. As of today, aqueous-based synthetic methods often lag behind their organic analogues in terms of the photophysical properties of the QDs obtained and the ease of modulation of both the emission wavelength and crystallite size. Using a novel microwave-assisted hydrothermal approach, the synthesis of silver sulphide (Ag2S) QDs exhibiting NIR emission spanning the biological transparency windows via modulation of the reaction parameters has been developed. The intrinsic link between their optical and structural properties is explored via laboratory and synchrotron-based structural analysis techniques. Their toxicity towards a hepatic cell line was assessed, and related back to their structure and size. Overall this work aims to not only further develop the repertoire of synthetic methods for the synthesis of Ag2S QDs, but also paves the way for the development of safer QDs suitable for future clinical applications.
KW - Quantum dots
KW - Microwave synthesis
KW - Quality assurance
KW - NIR-II emission
KW - PL quantum yield
KW - Ag2S
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634825
DO - https://doi.org/10.1039/d5nr00052a
SN - 2040-3372
VL - 17
IS - 24
SP - 14637
EP - 14646
PB - RSC
AN - OPUS4-63482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ladu, Luana
A1 - Matovic, Nikola
A1 - Imbert, Enrica
A1 - Encino-Munoz, Ana
T1 - How to measure the robustness and effectiveness of certification schemes and labels in ensuring the sustainability of bio-based products
N2 - The rapid proliferation of sustainability certification schemes and labels (CSLs) reflects the rising demand for sustainable products, although the robustness and effectiveness of these certification systems have been increasingly questioned. While CSLs aim to mitigate environmental and socio-economic risks and support responsible market practices, current monitoring systems of CSLs often lack coherence, transparency, and methodological robustness. This study addresses this gap by proposing a conceptual monitoring framework specifically tailored to the bioeconomy, addressing the complexity of global bio-based value chains. Developed through a systematic literature review, a comparative analysis of 26 academic studies and 19 monitoring tools, and stakeholder engagement via interviews and co-creation workshops, the framework introduces a multidimensional structure for evaluating CSLs across three core functions: (I) Building Trust and Transparency, (II) Protecting Sustainability Areas of Concern, and (III) Driving Continuous Improvement. A pilot benchmarking exercise using the Global Organic Textile Standard (GOTS) demonstrates the framework’s applicability and diagnostic value, revealing both strong alignment in some areas and performance gaps in others—particularly in the economic and circularity dimensions. The framework is designed as a dynamic and modular tool, suitable for use by policymakers, scheme owners, businesses, and consumers. It holds potential to harmonize evaluation practices, guide co-regulatory policy integration, and foster more transparent and credible sustainability certification systems in the bioeconomy meta-sector.
KW - Monitoring System
KW - Sustainability Certification Schemes
KW - Labels
KW - Standards
KW - Bioeconomy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640000
DO - https://doi.org/10.1016/j.jenvman.2025.126240
SN - 1095-8630
VL - 390
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-64000
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gladrow, K.
A1 - Unkovskiy, A.
A1 - Yassine, J.
A1 - Gaertner, N.
A1 - Topolniak, Ievgeniia
A1 - Henning, N.
A1 - Schmidt, F.
T1 - The effect of nitrogen atmosphere during post-curing on cytotoxicity, polishability, flexural strength, and surface hardness of 3D-printed denture bases: an in vitro study
N2 - 3D printing is increasingly utilized in dentistry. Compared to traditional manufacturing methods, 3D printing provides advantages such as faster production times and the ability to create complex structures. Although biocompatible materials are available, many are only suitable for temporary applications. This study examines the impact of nitrogen-aided post-processing on the mechanical properties and cytotoxicity of 3D-printed denture bases, with the hypothesis that this post-processing will enhance material properties and decrease cytotoxicity. Specimens were fabricated from V-print dentbase (Voco GmbH, Cuxhaven, Germany) and post-processed either in nitrogen or air. The specimens were categorized into aged and non-aged groups. For comparison, specimens made from milled material were utilized. Vickers hardness, flexural strength, polishability, cytotoxicity, and degree of conversion were then assessed for all groups. The data were analyzed using a one-way ANOVA and Tukey HSD test for multiple comparisons, with a significance threshold of p < 0.05. Post-curing with nitrogen improved the degree of conversion, surface hardness, and biocompatibility of 3D-printed dental materials, confirming reduced cytotoxicity without impairing mechanical properties. Nitrogen increased polymerization and decreased harmful monomers, making it ideal for clinical applications in contact with the oral mucosa. Optimizing post-processing steps, such as curing in nitrogen, enhances biocompatibility while maintaining strength and hardness, ensuring better patient care in dental applications.
KW - Biocompatibility
KW - V-Print
KW - Cytotoxicity
KW - Nitrogen
KW - Dentistry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654504
DO - https://doi.org/10.1007/s10856-026-07006-5
SN - 1573-4838
VL - 37
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65450
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hübner, Martin
A1 - Dittmann, Florian
A1 - Kromm, Arne
A1 - Varfolomeev, Igor
A1 - Kannengiesser, Thomas
T1 - Enhancement of the fatigue strength by application of a low transformation temperature (LTT) welding consumable
N2 - Low transformation temperature (LTT) welding consumables offer a possibility to enhance fatigue strength in welded components without post-treatment. By lowering the martensite start temperature (MS), the volume expansion during transformation near ambient temperature reduces welding related tensile residual stresses in fatigue-critical areas. To evaluate this effect, longitudinal stiffeners were used, a LTT and conventional filler serve as welding consumable, also high frequency mechanical impact (HFMI) treatment was carried out. Three single-pass and six additional-pass sample series were investigated on residual stress and fatigue strength. The additional welds were applied in fatigue crack critical areas with different weld shapes, achieved by varying welding parameters. Mechanical tests on reference samples evaluated the properties of the diluted LTT welds. Although reduced toughness was observed, no fatigue cracks occurred in LTT single-pass weld roots. The fatigue strength at two million cycles increased from 81 MPa to 121 MPa compared to conventional welds, while HFMI reached 146 MPa. With an additional LTT weld pass the results varied from 138 MPa to 196 MPa, depending to the shape and residual stress state. The results show that LTT fillers effectively enhance fatigue performance, and that weld geometry and parameter selection are as critical as the chemical composition for maximizing the LTT effect.
CY - Genua, Italy
DA - 22.06.2025
KW - Low transformation temperature (LTT)
KW - Martensite start temperature
KW - Residual stress
KW - Longitudenal stiffener
KW - Fatigue strength
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654520
DO - https://doi.org/10.1007/s40194-026-02356-8
SP - 1
EP - 14
PB - Springer Nature
AN - OPUS4-65452
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kleba-Ehrhardt, Rafael
A1 - Dávila, Josué
A1 - Geissler, Johann
A1 - Mohr, Gunther
A1 - Schmidt, Johannes
A1 - Heinze, Christoph
A1 - Hilgenberg, Kai
A1 - Gurlo, Aleksander
A1 - Karl, David
T1 - Influence of Haynes 282 powder oxidation on powder properties and component quality in laser powder bed fusion
N2 - Reuse of powder in powder bed additive manufacturing is a common practice to enhance sustainability and reduce costs. However, the reusability of metal powder is limited by the oxidation of the powders. Even in a protective atmosphere, each build job leads to gradual oxidation of the powder, which has led to concerns about its impact on powder and part properties. Consequently, strict confidence intervals for oxygen content in nickel-based alloy feedstocks are enforced in the industry. Despite this, there is currently a lack of in-depth studies investigating the specific influence of oxygen on Haynes 282, a widely used nickel-based alloy. This study examines artificially aged Haynes 282 powder batches with oxygen content of 160 ppm, 330 ppm, 1050 ppm, and 1420 ppm. Detailed powder characterization was performed, including morphology, chemical composition, particle size, flowability, and packing behavior. Components were fabricated via PBF-LB/M to evaluate density and mechanical properties. The results showed that higher oxidation levels improved powder flowability and packing density. However, in manufactured parts, irregular melt tracks and increased surface roughness were observed, which could easily be removed by post-processing. No significant differences in density or mechanical properties at room temperature, such as tensile strength and elongation, were found. These findings indicate that H282 powder potentially remains suitable for reuse, even when the batches exhibit increased oxygen content, supporting discussions on revising the existing oxygen content confidence intervals for nickel-based alloys. The results highlight the potential for optimizing recycling strategies and reducing material waste in additive manufacturing processes.
KW - Additive manufacturing
KW - Powder bed fusion
KW - Powder characterization
KW - Powder oxidation
KW - Powder recycling
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654545
DO - https://doi.org/10.1016/j.addma.2025.105050
SN - 2214-8604
VL - 116
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-65454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epple, Niklas
A1 - Sanchez Trujillo, Camila Andrea
A1 - Hau, Julia
A1 - Niederleithinger, Ernst
A1 - Malm, F.
T1 - Structural Monitoring in an Urban Underground Metro Station Using Cod
N2 - Active ultrasonic monitoring with coda wave interferometry has demonstrated its potential for structural Health monitoring in concrete structures. This study investigates its application using ultrasonic transducers embedded in the ceiling of a subway station in Munich, Germany. We evaluate the impact of environmental conditions, specifically electromagnetic interference and temperature, on data quality, as well as the influence of regular loading from passing trams. Results indicate that electromagnetic interference significantly affects measurements, while temperature effects remain minimal due to the station’s stable thermal environment. Long-term measurements and a controlled load test show that both dynamic and static loading from trams induce ultrasonic velocity changes of only 0.01%–0.06%. Although the experiment demonstrates the capacity to detect structural responses and supports the feasibility of long-term monitoring, improved electromagnetic shielding and Hardware reliability are required for successful future applications.
T2 - NDT-CE 2025
CY - Izmir, Turkey
DA - 24.09.2025
KW - Coda Wave Interferometry (CWI)
KW - Structural health monitoring (SHM)
KW - Concrete
KW - Ultrasonic testing
KW - Urban infrastructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654619
DO - https://doi.org/10.58286/31706
SN - 1435-4934
SP - 1
EP - 10
PB - e-Journal of Nondestructive Testing (eJNDT)
AN - OPUS4-65461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rahner, E.
A1 - Thiele, T.
A1 - Voss, Heike
A1 - Müller, F.A.
A1 - Bonse, Jörn
A1 - Gräf, S.
T1 - Objective, high-throughput regularity quantification of laser-induced periodic surface structures (LIPSS)
N2 - The growing demand for precise surface functionalization through laser-generated periodic surface structures highlights the necessity for efficient, reproducible, and objective evaluation methods to evaluate their structural regularity. We introduce ReguΛarity (v.1.2.7), a freely available, Python-based software with a graphical user interface for the automated, quantitative assessment of the regularity of laser-induced periodic surfaces structures (LIPSS), obtained from optical microscopy, SEM, or AFM. The software integrates image segmentation, one- and two-dimensional Fourier analyses, and gradient-based orientation determination to facilitate a comprehensive regularity analysis of grating-like (quasi-)periodic surface patterns with spatial periods Λ. This is achieved through the proposed regularity tuple R, composed of five key parameters: the normalized spread of the spatial period RΛ,2D (from 2D-FT), the normalized variation of the most frequent spatial period RΛ (from 1D-FT), the Gini coefficient G, the Dispersion of the LIPSS Orientation Angle δθ (DLOA), and the mean phase deviation . To demonstrate its applicability, we compare ideal sinusoidal patterns with SEM images obtained from LIPSS on stainless steel (AISI 316L) and aluminum alloy (AlMg5) surfaces, confirming the software’s ability to objectively distinguish between varying levels of structural regularity. ReguΛarity facilitates high-throughput analysis and data-driven process optimization in surface engineering and laser materials processing.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Image processing
KW - Regularity quantification
KW - Fourier analysis
KW - Structural homogeneity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654070
DO - https://doi.org/10.1016/j.apsusc.2026.165919
SN - 0169-4332
VL - 726
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-65407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittrich, Tim
A1 - Jansen, Daniel
A1 - Weise, Frank
A1 - Stelzner, Ludwig
A1 - Dehn, Frank
T1 - Thermal decomposition in blended cement systems and its effect on fire-induced concrete spalling: Insights from XRD and TGA
N2 - Blended cements are gaining increasing popularity due to their lower CO2-footprint in comparison to ordinary Portland cement (OPC). However, this growing use raises the potential risk of buildings made with blended cement concrete being exposed to fire, which can lead to heavy damages caused by explosive concrete spalling. It has already been shown that the cement type strongly influences the fire-induced concrete spalling and the thermally induced moisture transport, however, to understand the mechanisms behind these findings the thermal decomposition behavior of the cementitious matrix must be investigated more systematically. Therefore, the phase content of three blended cement pastes (CEM II/A-LL, CEM III/A and CEM II/B-Q) was studied in comparison with a Portland cement paste (CEM I) after temperature exposure to 20 ◦C, 105 ◦C, 300 ◦C and 500 ◦C. Clear differences in the initial phase composition and their dehydration behavior between the individual cement types were recognized. In conclusion, blended cements showed lower amounts of AFt and AFm phases and additionally lower amounts of portlandite and C-(A)-S-H were found in CEM III/A and CEM II/B-Q pastes. The results suggest that higher AFt and AFm contents in CEM I, which are associated with greater water release at relatively low temperatures may ultimately reduce the spalling risk. Furthermore, C-(A)-S-H in CEM III/A and CEM II/B-Q showed increased thermal stability and large amounts of non-hydrated phases were found in every blended cement paste. Both of those aspects might contribute to thermomechanical spalling and the overall increased spalling susceptibility observed in blended cement concrete.
KW - Fire concrete spalling
KW - High temperatures
KW - Blended cements
KW - Dehydration
KW - XRD
KW - TGA
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653698
DO - https://doi.org/10.1016/j.cscm.2026.e05784
SN - 2214-5095
VL - 24
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-65369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z. C.
A1 - Haist, M.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Schmid, M.
A1 - Kißling, P. A.
A1 - Leinitz, Sarah
A1 - Link, J.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Plank, J.
A1 - Schmidt, Wolfram
A1 - Schilde, C.
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Stephan, D.
T1 - Characterization data of reference cement CEM III/A 42.5N used for priority program DFG SPP 2005 "Opus Fluidum Futurum - Rheology of reactive, multiscale, multiphase construction materials"
N2 - Two types of cements were selected as the reference cement in the priority program 2005 of the German Research Foundation (DFG SPP 2005). A thorough characterization of CEM I 42.5 R has been made in a recent publication. In this paper, the characterization data of the other reference cement CEM III/A 42.5 N are presented from the aspects of chemical and mineralogical compositions as well as physical and chemical properties. The characterization data of the slag, which is the second main constituent of this specific cement besides the clinker, are presented independently. For all data received, the mean values and the corresponding errors were calculated. The data shall be used for the ongoing research within the priority program. Also, researchers from outside this priority program can benefit from these data if the same materials are used.
KW - Cement
KW - Slag
KW - Characterization
KW - DFG SPP 2005
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568980
DO - https://doi.org/10.1016/j.dib.2020.105524
SN - 2352-3409
VL - 30
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Asante, Bright
A1 - Soria-Castro, M.
A1 - Schmidt, Wolfram
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Influence of aquacultural and agricultural bio-admixtures and binder components on yield stress and strength of cementitious systems
N2 - Abstract: This study investigates the influence of bio-admixtures and bio-ashes from agricultural and aquaculture residues on the workability and strength of cement mortars. While bio-admixtures at low concentrations can enhance the strength, they create similar or lower yield stress as the reference. Bio ash, particularly at a 10% replacement level, maintained good strength, but higher replacements led to significant reductions in both strength and workability. These findings highlight the potential of sustainable construction materials but emphasize the need to balance performance specifications.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Agricultural bio-admixture
KW - Aquacultural bio-admixture
KW - Binder component
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612955
SN - 978-3-9818564-7-7
SP - 46
EP - 54
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Robens-Radermacher, Annika
A1 - Schmidt, Wolfram
A1 - Unger, Jörg F.
A1 - Mezhov, Alexander
T1 - Characterization of temperature influence on the structural build-up of 3D printed concrete
N2 - 3D concrete printing technologies enhance design freedom while reducing material use and costs without the need for formwork. Thereby, structural build-up is the key property governing stability and early strength evolution of 3D printed concrete after placement. Structural build-up is influenced by various factors, i.e., environmental conditions such as temperature. In this paper, the influence of ambient temperature on structural build-up was investigated through experimental and numerical approaches. Three experimental setups (small amplitude oscillatory shear, constant shear rate, and small amplitude oscillatory extensional tests) were applied to materials of increasing complexity under varying temperature conditions. A common modeling framework based on the maturity approach was developed to capture the time and temperature evolution. A stochastic framework was employed to estimate the unknown model parameters using experimental data. Experimental results demonstrate a significant temperature influence on structural build-up, consistent across all test setups and materials. The calibrated models successfully predict the structural build-up under different temperatures, confirming the applicability of the maturity approach to rheological parameters at early age. Furthermore, the stochastic parameter estimation allows a correct quantification of the uncertainties, enhancing model reliability. The comparison of two time evolution formulations indicates that a model with an additional linear stage is required for predicting the increase of the storage moduli (
$${G}{\prime}$$
G
′
,
$${E}{\prime}$$
E
′
). In conclusion, the study demonstrates that temperature significantly affects the structural build-up, and that the proposed modeling approach allows to predict this behavior.
KW - Structural build-up
KW - 3D concrete printing
KW - Rheology
KW - Temperature influence
KW - Modeling
KW - Green intelligent building
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654138
DO - https://doi.org/10.1617/s11527-025-02931-3
SN - 1359-5997
VL - 59
IS - 2
SP - 1
EP - 20
PB - Springer Science and Business Media LLC
AN - OPUS4-65413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yu, Jialu
A1 - Oelze, Marcus
A1 - Schannor, Mathias
A1 - Nordstad, Simon
A1 - Vogl, Jochen
T1 - New Potential Haematite and Magnetite Reference Materials for Iron Isotope Measurements by Solution Nebulisation MC ‐ ICP ‐ MS and by In Situ ns ‐ LA ‐ MC ‐ ICP ‐ MS
N2 - Iron isotope ratios of haematite (Fe2O3) and magnetite (Fe3O4) provide insights into geochemical, environmental and planetary processes. In most studies, Fe isotope measurements are commonly performed using solution nebulisation multi-collector inductively coupled plasma-mass spectrometry (SN-MC-ICP-MS). Nanosecond laser ablation multi-collector inductively coupled plasma-mass spectrometry (ns-LA-MC-ICP-MS) requires minimal sample preparation, and provides spatially resolved variation of iron isotopes at micro-scale. However, homogeneous and matrix-matched haematite/magnetite reference materials are lacking for precise in situ isotopic measurement. The iron isotope ratios of two potential reference materials resembling natural haematite (HMIE-NP-B01) and natural magnetite (MAKP-NP-B01) were characterised. Size fractions between 5–63 μm of the powdered Fe oxides were milled to nanoparticles, freeze-dried, homogenised, and pressed into pellets. The materials were then evaluated using SN-MC-ICP-MS and LA-MC-ICP-MS. Sample powders of the two materials were measured by SN-MC-ICPMS after sample digestion and column separation and pressed pellets were analysed directly via ns-LA-MC-ICP-MS. In both cases iron isotope delta values are reported relative to the certified reference material IRMM-014, used as the bracketing standard (calibrator). The solution measurements yielded δ56Fe values of -0.25 ± 0.08‰ (N = 13, 2s) for HMIE-NP-B01, and -0.05 ± 0.09‰ (N = 12, 2s) for MAKP-NP-B01, considered as the preferred Fe isotope delta values. In situ isotopic analysis via ns-LA-MC-ICP-MS yielded δ56Fe values of -0.28 ± 0.28‰ (N = 19, 2s) for HMIE-NP-B01 and -0.12 ± 0.24‰ (N = 22, 2s) for MAKP-NP-B01, consistent with the solution Fe isotope data. The homogeneity of Fe isotopes of the pellets was evaluated by ns-LA-MC-ICP-MS analyses of three different positions to further confirm that both materials are isotopically homogeneous. Both materials can be considered as potential quality control and bracketing reference materials for Fe isotopic measurements by in situ ns-LA-MC-ICP-MS analysis.
KW - Laser ablation
KW - Fe isotope
KW - Fe-oxides
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654755
DO - https://doi.org/10.1111/ggr.70037
SN - 1639-4488
SP - 1
EP - 12
PB - John Wiley & Sons Ltd.
AN - OPUS4-65475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schusterbauer, Robert
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Corrao, Elena
A1 - Zurutuza, Amaia
A1 - Doolin, Alexander
A1 - Pellegrino, Francesco
A1 - Radnik, Jörg
A1 - Donskyi, Ievgen S.
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative Chemical Imaging to Reveal the Nature of Different Commercial Graphene Materials
N2 - Proper physicochemical characterization of advanced materials and complex industrial composites remains a significant challenge, particularly for nanomaterials, whose nanoscale dimensions and mostly complex chemistry challenge the analysis. In this work, we employed a correlative analytical approach that integrates atomic force microscopy (AFM), scanning electron microscopy (SEM) coupled with energy‐dispersive X‐ray spectroscopy (EDS), time‐of‐flight secondary ion mass spectrometry (ToF‐SIMS), Auger electron spectroscopy (AES), and Raman spectroscopy. This combination enables detailed chemical and structural characterization with sub‐micrometer spatial resolution. Three commercial graphene‐based materials of varying complexity were selected and investigated to test the analytical performance of this approach. Furthermore, one of the commercial graphene oxide samples was chemically functionalized via amination and fluorination. This allowed us to assess how surface modifications influence both the material properties and the limits of the applied analytical techniques.
KW - Analytical methods
KW - Commercial products
KW - Correlative analysis
KW - Graphene
KW - Surface imaging
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654765
DO - https://doi.org/10.1002/smtd.202502344
SN - 2366-9608
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-65476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yao, Xingyu
A1 - Antunes, Margarida M.
A1 - Guilherme Buzanich, Ana
A1 - Cabanelas, Pedro
A1 - Valente, Anabela A.
A1 - Pinna, Nicola
A1 - Russo, Patrícia A.
T1 - Formation, Phase Transition, Surface, and Catalytic Properties of Cubic ZrO 2 Nanocrystals
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-Performance sodium storage anode. The presence of iron triggers the loss of long-rangeorder through disorder of the FeO6 octahedra local structure, subsequentlyallowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites forpseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - XAS
KW - Sodium-ion Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654955
DO - https://doi.org/10.1021/acs.chemmater.5c01483
SN - 0897-4756
VL - 37
IS - 21
SP - 8568
EP - 8580
PB - American Chemical Society (ACS)
AN - OPUS4-65495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallis, Theophilus
A1 - Ratanaphan, Sutatch
A1 - Darvishi Kamachali, Reza
T1 - Linking atomistic and phase-field modeling of grain boundaries I: Coarse-graining atomistic structures
N2 - The longstanding gap between atomistic and mesoscale simulations partly lies in the absence of a direct, physically grounded connection between atomic structure and mesoscale fields. In this work, we present a robust coarse-graining approach to systematically investigate the connection between phase-field and atomistic simulations of grain boundaries (GBs). The atomistic structures of 408 GBs in BCC-Fe and -Mo were studies to compute and analyze a continuous atomic density field. We discover a fundamental relationship between the GB density---defined as the average atomic density at the GB plane---and the GB excess free volume, an integral property of the boundary. An almost perfect linear correlation between the GB atomic density and GB excess free volume is identified. We also show that the width of BCC GBs, when scaled by the lattice constant, approaches a universal constant value. The relationships among GB density, width, and energy are systematically examined for various GB planes, and the GB energy--density correlations are classified with respect to GB types. It turns out that the atomic planes forming the GB strongly influence both the GB density and excess volume. The current results establish a dependable framework to bridge across scales, enabling density-based phase-field modeling of GBs with atomistic fidelity and enhancing the predictive reliability of mesoscale simulations.
KW - Density-based model
KW - Grain boundary structure
KW - Grain boundary thermodynamic
KW - Atomistic simulations
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654872
DO - https://doi.org/10.1016/j.actamat.2025.121786
SN - 1359-6454
VL - 305
SP - 1
EP - 14
PB - Elsevier Inc.
AN - OPUS4-65487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wallis, Theophilus
A1 - Darvishi Kamachali, Reza
T1 - Linking atomistic and phase-field modeling of grain boundaries II: Incorporating atomistic potentials into free energy functional
N2 - The density-based phase-field model for grain boundary (GB) thermodynamics and kinetics has offered a broad range of applications in alloy and microstructure design. Originally, this model is based on a potential energy terms that is connected to the cohesive energy of a given substance. A more rigorous approach, however, is a full consideration of an interatomic potential over the possible range of distance and therefore density. In Manuscript I of this series, we developed and thoroughly analyzed the coarse-graining of atomistic GB structures. In this work (Manuscript II), we complete the coupling between atomic and mesoscale modeling of GBs by incorporating the full interatomic potentials into the density-based free energy functional. Using GB energies calculated from atomistic simulations, the coarse-graining approach and the atomistic-integrated density-based Gibbs free energy, we effectively evaluate the density gradient energy coefficient. We found that coupling the density-based model with atomistic potentials reveal physically-sound trends in the GB equilibrium properties. A universal equation was derived to describe the potential energy contribution to the GB energy and the gradient energy coefficient for BCC-Fe and -Mo GBs, similar to the universal equation for GB excess free volume presented in Manuscript I. The proposed approach provides a mesoscale density-based model rooted in atomic-scale characteristics for reliable predictions of GB properties.
KW - Density-based model
KW - Phase-field
KW - Grain boundary structure
KW - Grain boundary thermodynamics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654904
DO - https://doi.org/10.1016/j.actamat.2025.121787
SN - 1359-6454
VL - 305
SP - 1
EP - 17
PB - Elsevier
AN - OPUS4-65490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yanchen
A1 - Guilherme Buzanich, Ana
A1 - Alippi, Paola
A1 - Montoro, Luciano A.
A1 - Lee, Kug‐Seung
A1 - Jeon, Taeyeol
A1 - Weißer, Kilian
A1 - Karlsen, Martin A.
A1 - Russo, Patrícia A.
A1 - Pinna, Nicola
T1 - FeNb 2 O 6 as a High‐Performance Anode for Sodium‐Ion Batteries Enabled by Structural Amorphization Coupled with NbO 6 Local Ordering
N2 - Pseudocapacitance-type transition metal oxides have been extensively investigated as anodes for lithium-ion batteries (LIBs). Currently, they are also gaining attention for sodium-ion batteries (SIBs) due to their low volume change and safety. However, their performance in sodium storage remains limited, primarily due to the larger Na+ ion radius. Here, for the first time, an iron niobate is reported with a columbite structure as a high-performance sodium storage anode. The presence of iron triggers the loss of long-range order through disorder of the FeO6 octahedra local structure, subsequently allowing reversible sodium storage in an amorphous phase. Simultaneously, the formation of short-range ordered zigzag-chain structures within the NbO6 planes creates a “skeleton” that offers abundant active sites for pseudocapacitive ion storage and enhanced ion diffusion pathways. These characteristics of FeNb2O6 make it an effective intercalation host, offering high capacity along with fast Na+ kinetics, as demonstrated through operando and ex situ characterizations. It leads to an applicable reversible capacity (>300 mAh g−1) with a favorable average voltage of ≈0.6 V and excellent rate capability (180.4 mAh g−1 at a current density of 2 A g−1). This study provides insights into the development of intrinsically active transition metal oxides for Na+-ion intercalation.
KW - SIB
KW - XAS
KW - Sodium-ion Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654931
DO - https://doi.org/10.1002/adma.202504100
SN - 0935-9648
VL - 37
IS - 46
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-65493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Ott, C.
A1 - Das, S. M.
A1 - Liebscher, C.
A1 - Samwer, K.
A1 - Derlet, P. M.
A1 - Maaß, Robert
T1 - On the elastic microstructure of bulk metallic glasses
N2 - Metallic glasses (MGs) are known to be structurally heterogeneous at the nanometer (nm) scale. In addition, elastic property mapping has indicated the presence of at least an order-of-magnitude larger length scales, of which the origin continues to remain unknown. Here we demonstrate the existence of an elastic decorrelation length of the order of 100 nm in a Zr-based bulk MG using spatially resolved elastic property mapping via nanoindentation. Since compositional modulations sufficiently large to account for this elastic microstructure were not resolved by analytical scanning-transmission electron microscopy, chemical phase separation such as spinodal decomposition cannot explain their occurrence as previously suggested. Instead, we argue that the revealed long-range elastic modulations stem from structural variations affecting the local density. These emerge during solidification and are strongly influenced by the cooling constraints imposed on bulk MGs during the casting process.
KW - Metallic glasses
KW - Nanoindentation
KW - Elastic microstructure
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573504
DO - https://doi.org/10.1016/j.matdes.2023.111929
SN - 0264-1275
VL - 229
SP - 1
EP - 8
PB - Elsevier Ltd.
CY - Amsterdam, Niederlande
AN - OPUS4-57350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
A1 - Wallis, Theophilus
A1 - Ikeda, Yuki
A1 - Saikia, U.
A1 - Ahmadian, A.
A1 - Liebscher, C.
A1 - Hickel, Tilmann
A1 - Maaß, Robert
T1 - Giant segregation transition as origin of liquid metal embrittlement in the Fe-Zn system
N2 - A giant Zn segregation transition is revealed using CALPHAD-integrated density-based modeling of segregation into Fe grain boundaries (GBs). The results show that above a threshold of only a few atomic percent Zn in the alloy, a substantial amount of up to 60 at.% Zn can segregate to the GB. We found that the amount of segregation abruptly increases with decreasing temperature, while the Zn content in the alloy required for triggering the segregation transition decreases. Direct evidence of the Zn segregation transition is obtained using high-resolution scanning transmission electron microscopy. Base on the model, we trace the origin of the segregation transition back to the low cohesive energy of Zn and a miscibility gap in Fe-Zn GB, arising from the magnetic ordering effect, which is confirmed by ab-initio calculations. We also show that the massive Zn segregation resulting from the segregation transition greatly assists with liquid wetting and reduces the work of separation along the GB. The current predictions suggest that control over Zn segregation, by both alloy design and optimizing the galvanization and welding processes, may offer preventive strategies against liquid metal embrittlement.
KW - CALPHAD
KW - Microstructure Design
KW - Grain boundary engineering
KW - Steels
KW - Density-based Model
KW - Segregation Engineering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584292
DO - https://doi.org/10.1016/j.scriptamat.2023.115758
SN - 1359-6462
SN - 1872-8456
VL - 238
SP - 1
EP - 5
PB - Elsevier
CY - Amsterdam
AN - OPUS4-58429
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiedeitz, M.
A1 - Schmidt, Wolfram
A1 - Härder, M.
A1 - Kränkel, T.
T1 - Performance of rice husk ash as supplementary cementitious material after production in the field and in the lab
N2 - Supplementary cementitious materials (SCM) can reduce the total amount of Portland cement clinker in concrete production. Rice husk ashes (RHA) can be converted from an agricultural by-product to a high-performance concrete constituent due to a high amount of reactive silica with pozzolanic properties if they are burnt under controlled conditions. The way and duration of combustion, the cooling process as well as the temperature have an effect on the silica form and thus, the chemical and physical performance of the RHA. Various studies on the best combustion technique have been published to investigate the ideal combustion techniques. Yet, the process mostly took place under laboratory conditions. Investigating the difference between the performance of RHA produced in a rural environment and laboratory conditions is useful for the assessment and future enhancement of RHA production, and its application both as building material, for example in rural areas where it is sourced in large quantities, and as additive for high performance concrete. Thus, the paper presents a comparison between RHA produced under rudimentary conditions in a self-made furnace in the rural Bagamoyo, Tanzania and under controlled laboratory conditions at the Technical University of Munich, Germany, with different combustion methods and temperatures. In a second step, RHA was ground to reach particle size distributions comparable to cement. In a third step, cement pastes were prepared with 10%, 20% and 40% of cement replacement, and compared to the performance of plain and fly ash blended cement pastes. The results show that controlled burning conditions around 650 °C lead to high reactivity of silica and, therefore, to good performance as SCM. However, also the RHA burnt under less controlled conditions in the field provided reasonably good properties, if the process took place with proper burning parameters and adequate grinding. The knowledge can be implemented in the field to improve the final RHA performance as SCM in concrete.
KW - Rice husk ash
KW - Agricultural by-product
KW - Supplementary cementitious material
KW - Waste management
KW - Carbon dioxide emissions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568953
DO - https://doi.org/10.3390/ma13194319
SN - 1996-1944
VL - 13
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-56895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Munsch, Sarah Mandy
A1 - Telong, Melissa
A1 - Schmidt, Wolfram
A1 - Bintz, Thilo
A1 - Fladt, Matthias
A1 - Stelzner, Ludwig
T1 - The NMR core analyzing TOMograph: A multi-functional tool for non-destructive testing of building materials
N2 - NMR is becoming increasingly popular for the investigation of building materials as it is a non-invasive technology that does not require any sample preparation nor causes damage to the material. Depending on the specific application it can offer insights into properties like porosity and spatial saturation degree as well as pore structure. Moreover it enables the determination of moisture transport properties and the (re-)distribution of internal moisture into different reservoirs or chemical phases upon damage and curing. However, as yet most investigations were carried out using devices originally either designed for geophysical applications or the analysis of rather homogeneous small scale (< 10 mL) samples. This paper describes the capabilities of an NMR tomograph, which has been specifically optimized for the investigation of larger, heterogeneous building material samples (diameters of up to 72 mm, length of up to 700 mm) with a high flexibility due to interchangeable coils allowing for a high SNR and short echo times (50 - 80 m s).
KW - Fire spalling
KW - Moisture transport
KW - Concrete
KW - Cement hydration
KW - Sensitivity
KW - Supplementary cementitous materials
KW - Frost salt attack
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573755
DO - https://doi.org/10.1016/j.mrl.2023.03.004
SN - 2097-0048
VL - 3
IS - 3
SP - 207
EP - 219
PB - Elsevier B.V.
AN - OPUS4-57375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kar, Satyakam
A1 - Ikeda, Yuki
A1 - Nielsch, Kornelius
A1 - Reith, Heiko
A1 - Maaß, Robert
A1 - Fähler, Sebastian
T1 - Multiferroic Microstructure Created from Invariant Line Constraint
N2 - Ferroic materials enable a multitude of emerging applications, and optimum functional properties are achieved when ferromagnetic and ferroelectric properties are coupled to a first‐order ferroelastic transition. In bulk materials, this first‐order transition involves an invariant habit plane, connecting coexisting phases: austenite and martensite. Theory predicts that this plane should converge to a line in thin films, but experimental evidence is missing. Here, the martensitic and magnetic microstructure of a freestanding epitaxial magnetic shape memory film is analyzed. It is shown that the martensite microstructure is determined by an invariant line constraint using lattice parameters of both phases as the only input. This line constraint explains most of the observable features, which differ fundamentally from bulk and constrained films. Furthermore, this finite‐size effect creates a remarkable checkerboard magnetic domain pattern through multiferroic coupling. The findings highlight the decisive role of finite‐size effects in multiferroics.
KW - Epitaxial films
KW - Finite-size effects
KW - Multiferroics
KW - Martensite
KW - Magnetic shape memory alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637910
DO - https://doi.org/10.1002/adfm.202416638
SN - 1616-301X
VL - 35
IS - 10
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-63791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maaß, Robert
A1 - Derlet, P.
T1 - Micro-plasticity in a fragile model binary glass
N2 - Atomistic deformation simulations in the nominally elastic regime are performed for a model binary glass with strain rates as low as 10 4 /s (corresponding to 0.01 shear strain per 1 μs). A strain rate dependent elastic softening due to a micro-plasticity is observed, which is mediated by thermally-activated localized structural transformations (LSEs). A closer inspection of the atomic-scale structure indicates the material response is distinctly different for two types of local atomic environments. A system spanning iscosahe- drally coordinated substructure responds purely elastically, whereas the remaining substructure admits both elastic and microplastic evolution. This leads to a heterogeneous internal stress distribution which, upon unloading, results in negative creep and complete residual-strain recovery. A detailed structural analysis in terms of local stress, atomic displacement, and SU(2) local bonding topology shows such mi- croscopic processes can result in large changes in local stress and are more likely to occur in geomet- rically frustrated regions characterized by higher free volume and softer elastic stiffness. The thermally- activated LSE activity also mediates structural relaxation, and in this way should be distinguished from stress-driven shear transformation activity which only rejuvenates glass structure. The frequency of LSE activity, and therefore the amount of micro-plasticity, is found to be related to the degree to which the glassy state is relaxed. These insights shed atomistic light onto the structural origins that may govern re- cent experimental observations of significant structural evolution in response to elastic loading protocols.
KW - Molecular dynamics
KW - Bulk metallic glasses
KW - Plasticity
KW - Residual strains
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523782
DO - https://doi.org/10.1016/j.actamat.2021.116771
VL - 209
SP - 116771
PB - Elsevier Ltd.
AN - OPUS4-52378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Yuan, R.
A1 - Chakraborty, A.
A1 - Ghassemi-Armaki, H.
A1 - Zuo, J. M.
A1 - Maaß, Robert
T1 - Early stages of liquid-metal embrittlement in an advanced high-strength steel
N2 - Grain-boundary degradation via liquid-metal embrittlement (LME) is a prominent and long-standing failure process in next generation advanced high-strength steels. Here we reveal, well ahead of the crack tip, the presences of nano-scale grains of intermetallic phases in Zn-infiltrated but uncracked grain boundaries with scanning- and 4D transmission electron microscopy. Instead of the often-reported Znrich Fe-Zn intermetallics, the nano-scale phase in the uncracked infiltrated grain boundaries is identified as the G-phase, and its presence reveals the local enhancement of strain heterogeneities in the grain boundary network. Based on these observations, we argue that intermetallic phase formation is not occurring after cracking and subsequent liquid Zn infiltration but is instead one of the primary nanoscopic drivers for grain-boundary weakening and crack initiation. These findings shift the focus of LME from micro- and meso-scale crack investigations to the very early stages immediately following Zn diffusion, after which secondary phase nucleation and growth emerge as the root-cause for failure.
KW - Advanced high strength steels
KW - Liquid metal embrittlement
KW - Transmission electron microscopy
KW - 4-Dimensional scanning transmission
KW - electron microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539716
DO - https://doi.org/10.1016/j.mtadv.2021.100196
SN - 2590-0498
VL - 13
IS - 196
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-53971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sreekala, L.
A1 - Dey, P.
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
T1 - Unveiling nonmonotonic chemical trends in the solubility of H in complex Fe-Cr-Mn carbides by means of ab initio based approaches
N2 - The microstructure of advanced high-strength steels often shows a sensitive dependence on alloying. For example, adding Cr to improve the corrosion resistance of medium-Mn steels also enhances the precipitation of carbides. The current study focuses on the behavior of H in such complex multicomponent carbides by employing different methodological strategies. We systematically analyze the impact of Cr, Mn, and Fe using density functional theory (DFT) for two prototype precipitate phases, M3C and M23C6, where M represents the metal sublattice. Our results show that the addition of these alloying elements yields strong nonmonotonic chemical trends for the H solubility. We identify magnetovolume effects as the origin for this behavior, which depend on the considered system, the sites occupied by H, and short- vs long-range interactions between H and the alloying elements. We further show that the H solubility is directly correlated with the occupation of its nearest-neighbor shells by Cr and Mn. Based on these insights, DFT data from H containing binary-metal carbides are used to design a ridge regression based model that predicts the solubility of H in the ternary-metal carbides (Fe-Cr-Mn-C).
KW - Hydrogen
KW - High-strength steel
KW - Carbide
KW - Ab initio
KW - Complexity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542271
DO - https://doi.org/10.1103/PhysRevMaterials.6.014403
SN - 2475-9953
VL - 6
IS - 1
SP - 1
EP - 14
PB - American Physical Society (APS)
CY - College Park, MD
AN - OPUS4-54227
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maaß, Robert
T1 - Beyond Serrated Flow in Bulk Metallic Glasses: What Comes Next?
N2 - This manuscript is based on an oral contribution to the TMS 2020 annual meeting and is dedicated to Prof. Peter Liaw, who for decades has shown great interest in serrated plastic flow.
Here we will focus on the case of bulk metallic glasses, and begin with briefly summarizing some aspects of serrated and non-serrated inhomogeneous flow—a phenomenon that has perplexed materials scientists for decades. Four directions of research are identified that emerged out of the desire to fundamentally understand the intermittent inhomogeneous flow response. These research directions gear away from the phenomenological stress–strain behavior but put the underlying shear defect into focus. Unsolved problems and future research topics are discussed.
KW - Non-serrated inhomogeneous flow
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513106
DO - https://doi.org/10.1007/s11661-020-05985-w
SN - 1073-5623
SP - 1
EP - 11
PB - Springer Nature
AN - OPUS4-51310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chakraborty, P.
A1 - Mouton, I.
A1 - Gault, B.
A1 - Tehranchi, Ali
A1 - Neugebauer, J.
A1 - Hickel, Tilmann
T1 - Effect of Sn on stacking fault energies in zirconium and its hydrides
N2 - Hydrogen embrittlement in Zr-alloy fuel cladding is a primary safety concern for water-based nuclear reactors. Here we investigated the stabilization of planar defects within the forming hydrides by Sn, the primary alloying element of Zircaloy-4 used in the cladding. In order to explain the formation of hydrides and planar defects observed in our experiments, we performed atomic-scale ab initio calculations focusing on the solute interactions with generalized stacking faults in hcp 𝛼-Zr and fcc zirconium hydrides. Our calculations showed that an increase in Sn concentration leads to a stabilization of stacking faults in both the 𝛼-Zr and hydride phases. However, the solution enthalpy of Sn is lower in the 𝛼-Zr as compared to the other hydride phases, indicative of two competing processes of Sn depletion/enrichment at the Zr hydride/matrix interface. This is corroborated by experimental findings, where Sn is less soluble in hydrides and is mostly found trapped at interfaces and planar defects, indicative of stacking faults inside the hydride phases. Our systematic investigation enables us to understand the presence and distribution of solutes in the hydride phases, which provides a deeper insight into the microstructural evolution of such alloy's properties during its service lifetime.
KW - Defects
KW - First-principles calculations
KW - Interface and surface thermodynamics
KW - Microstructure
KW - Hydrides
KW - Structural properties
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618044
DO - https://doi.org/10.1103/PhysRevMaterials.8.033605
SN - 2475-9953
VL - 8
IS - 3
SP - 1
EP - 9
PB - APS
AN - OPUS4-61804
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hickel, Tilmann
A1 - Divinski, S.
A1 - Starikov, S.
A1 - Soisson, F.
A1 - Mény, C.
A1 - Hegde, O.
A1 - Gerlitz, M.
A1 - Magnifouet, G.
A1 - Schneider, A.
A1 - Barreteau, C.
A1 - Mirebeau, I.
A1 - Tran, V.T.
A1 - Förster, G.
A1 - Front, A.
A1 - Egorov, A.
A1 - Wilde, G.
A1 - Amara, H.
A1 - Hammerschmidt, T.
A1 - Mrovec, M.
A1 - Pierron-Bohnes, V.
A1 - Drautz, R.
A1 - Fu, C.
T1 - Magnetism in iron alloys: methodological advances for thermodynamics, defects, and kinetics
N2 - Steels are among the technologically and economically most relevant materials. Key innovations in important sectors of human society such as mobility, energy and safety, are currently based on alloying of Fe with other transition-metal elements such as Mn, Cr, or Co. Due to strong impacts and conceptual challenges related to magnetism, however, the fundamental understanding and the ability to computationally design these steels in high-throughput approaches lags behind other classes of alloys. In this article, we will provide a substantial review of the role of magnetism, magnetic excitations and transformations for alloy thermodynamics, point defects, interfaces and kinetics. This will be achieved by combining insights from different methods: Ab initio simulations have the advantage that the magnetic ground state is intrinsic part of the electronic minimization. Due to the coarsening of the many-electron structures and therewith magnetic interactions, tight-binding methods can handle larger system sizes. Effective interaction models provide the freedom to exploit more sophisticated magnetic interactions. The performance of these methods in terms of magnetic properties of Fe alloys will be evaluated by providing state-of-the-art results for their sensitivity to magnetism. Furthermore, dedicated experiments will be discussed to complete the understanding of magnetic effects in Fe alloys and to validate the modeling strategy.
KW - Magnetic excitations
KW - Defects
KW - Diffusion
KW - Density functional theory
KW - Tight-binding
KW - Effective interaction models
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634530
DO - https://doi.org/10.1515/ijmr-2023-0225
SN - 1862-5282
VL - 60
IS - 99
SP - 1
EP - 14761
PB - Walter de Gruyter GmbH
AN - OPUS4-63453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mai, H. L.
A1 - Cui, X.-Y,
A1 - Hickel, Tilmann
A1 - Neugebauer, J.
A1 - Ringer, S. P.
T1 - A high-throughput ab initio study of elemental segregation and cohesion at ferritic-iron grain boundaries
N2 - Segregation of alloying elements and impurities at grain boundaries (GBs) critically influences material behaviour by affecting cohesion. In this study, we present an ab initio high-throughput evaluation of segregation energies and cohesive effects for all elements up to Z=92 in the periodic table (Z = 1–92, H–U) across the substitutional sites in six model ferritic iron GBs using density functional theory (DFT). From these data, we construct comprehensive elemental maps for solute segregation tendencies and cohesion at GBs, providing guidance for segregation engineering. We systematically assess the cohesive effects of different elements in all segregating positions along multiple fracture paths with a quantum-chemistry bond-order method as well as a modified Rice–Thomson–Wang theory of interfacial cohesion. The effects of segregants on the cohesion of GBs are shown to vary drastically as a function of site character, and hence their induced cohesive effects must
be considered as a thermodynamic average over the spectral energy distribution. Thus, models that overlook these aspects may fail to accurately predict the impacts of varying alloying concentrations, thermal processing conditions, or GB types. The insights presented here, along with our accompanying dataset, are expected to advance our understanding of GB segregation in steels and other materials.
KW - Defects
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638397
DO - https://doi.org/10.1016/j.actamat.2025.121288
SN - 1359-6454
VL - 297
SP - 1
EP - 16
PB - Elsevier Inc.
AN - OPUS4-63839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaiser, Erika
A1 - Fareed, Adnan
A1 - Manzoni, Anna Maria
A1 - Paulisch-Rinke, Melanie C.
A1 - Hsu, Wei-Che
A1 - Yeh, An-Chou
A1 - Murakami, Hideyuki
A1 - Vogel, Florian
A1 - Maaß, Robert
T1 - Pinning-dominated strengthening in high-entropy superalloys
N2 - Hierarchical microstructural design of high-entropy superalloys offers novel strengthening pathways beyond classical superalloys. Here we assess the strength of isolated γ’ precipitates with and without an additional internal γ nanophase. The results show that nano-precipitation within the γ’ phase leads to a marked statistical reduction of the dislocation-nucleation limited yield strength. In concert with disorder-driven chemical weakening of the γ’ phase, these findings indicate that bulk strengthening due to hierarchical microstructural design in high entropy superalloys must primarily be pinning dominated.
KW - High-entropy alloys
KW - Superalloys
KW - Dislocation nucleation
KW - Plasticity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637590
DO - https://doi.org/10.1016/j.scriptamat.2025.116874
SN - 1359-6462
VL - 268
SP - 1
EP - 6
PB - Elsevier Inc.
AN - OPUS4-63759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ikeda, Yuki
A1 - Han, Seungchang
A1 - Wallis, Theophilus
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - On the preference of liquid-metal embrittlement along high-angle grain-boundaries in galvanized steels
N2 - Focusing on the early stages of liquid-metal embrittlement (LME) of Zinc (Zn) coated advanced high-strength steels, we show that the Zn infiltration path prior to grain-boundary decohesion and therefore cracking distinctly follows high-angle grain boundaries (HAGBs). This selective transport prior to LME-induced microcracking rationalizes the experimentally observed post-mortem cracking along martensitic HAGBs. We discuss the selective Zn transport and GB-weakening in terms of an misorientation-angle dependent atomic density and diffusivity, and its effect on GB-segregation.
KW - Liquid-metal embrittlement
KW - Advanced high-strength steels
KW - Grain boundaries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631103
DO - https://doi.org/10.1016/j.scriptamat.2025.116723
SN - 1359-6462
VL - 265
SP - 1
EP - 5
PB - Elsevier Inc.
AN - OPUS4-63110
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roters, F.
A1 - Aslam, A.
A1 - Bai, Y.
A1 - Büschelberger, M.
A1 - Bulert, K.
A1 - Butz, A.
A1 - Hickel, Tilmann
A1 - Jogi, T.
A1 - Klitschke, S.
A1 - Martin, M.
A1 - Meyer, L.-P.
A1 - Morand, L.
A1 - Nahshon, Y.
A1 - Radtke, N.
A1 - Saikia, Ujjal
A1 - Trondl, A.
A1 - Wessel, A.
A1 - Zierep, P.
A1 - Helm, D.
T1 - StahlDigital: Ontology-Based Workflows for the Steel Industry
N2 - The innovative strength of the steel industry is based on the mastery of microstructure–property relationships. Digital workflows can largely contribute to this aim by making the complexity of workflows reproducible and their execution user independent. In this work, the tools and workflows developed in the project StahlDigital as part of the German MaterialDigital initiative are presented and application examples are provided. A steel ontology builds the
foundation for data collection and storage as well as for the semantic description of experimental and simulation data processing workflows. A dataspace powered by the Dataspace Management System (DSMS) digitally represents such workflows and manages data along them in a Findable, Accessible, Interoperable, Reusable manner aiming to derive new knowledge. Experimental data processed via DSMS can be further evaluated and used as input for simulation workflows. The simulations included in such workflows are run by the workflow system pyiron, which has been semantically extended in StahlDigital for this purpose.
KW - Steel
KW - Rolling
KW - Multiscale simulation
KW - Ontology
KW - Workflow
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627187
DO - https://doi.org/10.1002/adem.202402148
SN - 1527-2648
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-62718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
A1 - Kamashanju, Kabibi Charles
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Circular, bio-based, intelligent ecosystems for climate friendly construction materials supplies
N2 - Abstract: Concrete is a major contributor to global energy demand and CO2-emissions, necessitating mitigation strategies. Utilising bio-based resources like polysaccharides, pozzolanic ashes from agricultural waste, and bio-based fibres and aggregates can reduce carbon footprints. However, implementation is hindered by stand- ards favouring scarce and traditionally European materials like fly ash and slag. This highlights the need to diversify resource streams to benefit the global South's abundance of bio-based resources and arable land. An inclusive approach recognizing bio-based resources is required through innovation and regional adaptation.
T2 - 63. Forschungskolloquium Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Intelligent ecosystems
KW - CO2-emissions
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613160
SN - 978-3-9818564-7-7
SP - 102
EP - 113
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tlhatlha, Pheladi
A1 - Schmidt, Wolfram
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Policies and codes for sustainable cement and concrete technologies in the Global South
N2 - Abstract: This paper explores three primary pathways for improving sustainable cement and concrete technologies: cement production, concrete production, and recycling technologies. It underscores the importance of policy frameworks for transitioning from prescriptive to performance-based standards to foster innovation and support low-carbon technologies, while also addressing the economic, political, and social drivers that shape policy and industry practices. The research questions the replication of Global North standards in the Global South, advocating for locally adapted, unique regional policies.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Sustainable cement
KW - Concrete technologies
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613170
SN - 978-3-9818564-7-7
SP - 114
EP - 122
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61317
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Rheologie von Bindemittelsuspensionen in Gegenwart von Biopolymeren
N2 - Zusatzmittel sind unverzichtbarer Bestandteil von modernem Beton. Ihr Einsatz ist nicht nur technisch und wirtschaftlich sinnvoll, sondern auch notwendig, um Beton umweltfreundlicher zu machen. In diesem Zusammenhang gewinnen nachhaltige Biopolymere zunehmend an Bedeutung, sie weisen jedoch eine große Vielfalt an Molekularstrukturen auf, die zu Unverträglichkeiten mit anderen - wie z.B. Fließmitteln - führen können. In dieser Arbeit werden die Auswirkungen des kombinierten Einsatzes verschiedener Zusatzmittel im Hinblick ihres Einflusses auf die Zementhydratation und den Strukturaufbau von Zementpasten untersucht.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Rheologie
KW - Bindemittelsuspension
KW - Biopolymer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613089
SN - 978-3-9818564-7-7
SP - 147
EP - 152
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61308
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Wolfram
A1 - Kanjee, J.
A1 - Motukwa, G.
A1 - Olonade, K.
A1 - Dodoo, A.
T1 - A snapshot review of future‑oriented standards for cement, admixtures, and concrete: How Africa can spearhead the implementation of green urban construction materials
N2 - The existing cement and concrete standards are not capable of making full use of the current technology capacity due to strong focus on conventional concrete and thus they are not fit for the current and future challenges of construction industry. The paper highlights shortcomings with regard to the implementation of the existing standards. It can be seen that future-oriented standards are generally required to contribute to a lower-carbon footprint of the industry. These changes are significantly more relevant in sub-Saharan Africa, due to the rapidly increasing urbanisation challenge and the enormous potentials to develop lower-carbon technologies than elsewhere in the world.
KW - Future‑oriented standards
KW - Green urban construction
KW - Cement
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582563
DO - https://doi.org/10.1557/s43580-023-00563-9
SN - 2731-5894
VL - 4
IS - 8
SP - 557
EP - 565
PB - Springer International Publishing
CY - Springer Nature Switzerland, Cham
AN - OPUS4-58256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Z.
A1 - Becker, S.
A1 - Leinitz, Sarah
A1 - Schmidt, Wolfram
A1 - von Klitzing, R.
A1 - Stephan, D.
T1 - Interaction of Different Charged Polymers with Potassium Ions and Their Effect on the Yield Stress of Highly Concentrated Glass Bead Suspensions
N2 - The interaction of different charged polymers, namely anionic polycarboxylate
superplasticizer (PCE) and neutral polyethylene glycol (PEG) with potassium ions, and their effect on the yield stress of highly concentrated glass bead suspension (GBS), were studied under different concentrations of potassium ions ([K+]). It was found that, compared to the neutral PEG, the negatively charged PCE can be adsorbed on glass beads (GB), and then decreases the yield stress of GBS. The increasing concentration of free polymer in the interstitial liquid phase with the increased polymer dosage leads to the higher yield stress of GBS, which may be caused by the higher Depletion force. In addition, this effect is also related to the charge density of the polymer and the [K+] in the solution. Along with the increase in [K+], the yield stress of GBS increases significantly with the addition of PCE, but this cannot be observed with PEG, which indicates that potassium ions can interact with negatively charged PCE instead of the neutral PEG. At last, the interparticle Forces between two single GB with adsorbed PCE in solutions containing [K+] and PCE were measured by colloidal probe atomic force microscopy to better understand the interaction of the charged polymer with counterions.
KW - Yield stress
KW - Free polymer
KW - Charge density
KW - Depletion force
KW - Potassium ions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506015
DO - https://doi.org/10.3390/ma13071490
SN - 1996-1944
VL - 13
IS - 7
SP - 1490, 1
EP - 1490, 16
PB - MDPI
AN - OPUS4-50601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pott, U.
A1 - Crasselt, Claudia
A1 - Fobbe, N.
A1 - Haist, M.
A1 - Heinemann, M.
A1 - Hellmann, S.
A1 - Ivanov, D.
A1 - Jakob, C.
A1 - Jansen, D.
A1 - Lei, L.
A1 - Li, R.
A1 - Link, J.
A1 - Lowke, D.
A1 - Mechtcherine, V.
A1 - Neubauer, J.
A1 - Nicia, D.
A1 - Plank, J.
A1 - Reißig, S.
A1 - Schäfer, T.
A1 - Schilde, C.
A1 - Schmidt, Wolfram
A1 - Schröfl, C.
A1 - Sowoidnich, T.
A1 - Strybny, B.
A1 - Ukrainczyk, N.
A1 - Wolf, J.
A1 - Xiao, P.
A1 - Stephan, D.
T1 - Characterization data of reference materials used for phase II of the priority program DFG SPP 2005 “Opus Fluidum Futurum –Rheology of reactive, multiscale, multiphase construction materials”
N2 - A thorough characterization of base materials is the prereq- uisite for further research. In this paper, the characterization data of the reference materials (CEM I 42.5 R, limestone pow- der, calcined clay and a mixture of these three components) used in the second funding phase of the priority program 2005 of the German Research Foundation (DFG SPP 2005) are presented under the aspects of chemical and min- eralogical composition as well as physical and chemical properties. The data were collected based on tests performed by up to eleven research groups involved in this cooperative program.
KW - Portland cement
KW - Limestone powder
KW - Calcined clay
KW - Sustainable cement
KW - DFG SPP 2005
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569913
DO - https://doi.org/10.1016/j.dib.2023.108902
VL - 47
SP - 1
EP - 19
PB - Elsevier
AN - OPUS4-56991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Robens-Radermacher, Annika
A1 - Unger, Jörg F.
A1 - Mezhov, Alexander
A1 - Schmidt, Wolfram
ED - Biondini, F.
ED - Frangopo, D. M.
T1 - Temperature dependent modelling approach for early age behavior of printable mortars
N2 - Structural build-up describes the stability and early-age strength development of fresh mortar used in 3D printing. lt is influenced by several factors, i.e. the composition of the print able material, the printing regime, and the ambient conditions. The existing modelling approaches for structural build-up usually define the model parameters for a specific material composition with out considering the influence of the ambient conditions. The goal of this contribution is to explicitly include the temperature dependency in the modelling approach. Temperature changes have signifi cant impact on the structural build-up process: an increase of the temperature leads to a faster dissol ution of cement phases and accelerates hydration. The proposed extended model includes temperature dependency using the Arrhenius theory. The new model parameters are successfully calibrated based on Viskomat measurement data using Bayesian inference. Furthermore, a higher impact of the temperature in the re-flocculation as in the structuration stage is observed.
T2 - The Eighth International Symposium on Life-Cycle Civil Engineering (IALCCE 2023)
CY - Milano, Italien
DA - 02.07.2023
KW - 3D concrete printing
KW - Material characterization
KW - Structural build-up
KW - Thixotropy
KW - Model calibration
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582175
SN - 978-1-003-32302-0
DO - https://doi.org/10.1201/9781003323020-146
SN - 978-1-003-32302-0
VL - 1st Edition
SP - 1193
EP - 1200
PB - CRC Press
AN - OPUS4-58217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Wolfram
A1 - Tchetgnia Ngassam, Ines Leana
A1 - Olonade, K. A.
A1 - Mbugua, R.
A1 - Kühne, Hans-Carsten
T1 - Plant based chemical admixtures – potentials and effects on the performance of cementitious materials
N2 - While today, engineers can choose from a wide range of rheology modifying admixtures, in some parts of the world, these are difficult to access, due to their complex processing. However, alternatives can be bio‐based polymers such as polysaccharides from various sources. These are easily accessible all over the world, do not demand for complicated processing, and typically they are more sustainable than many established materials, which are crude oil‐based.
The paper presents the effects of acacia gum, cassava starch and the gum of triumfetta pendrata A. Rich on the rheological performance of cementitious systems. It is shown that acacia gum can be as efficient as polycarboxylate based superplasticisers, cassava starch can reduce the yield stress slightly with little effect on the plastic viscosity, and the gum of triumfet ta pendrata A. Rich increases the thixotropy of cement pastes with plasticizing polymers significantly.
KW - Polysaccharides
KW - Rheology
KW - Cement
KW - Chemical admixtures
KW - Bio-based concrete
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476748
DO - https://doi.org/10.21809/rilemtechlett.2018.83
VL - 3
SP - 124
EP - 128
PB - RILEM S.A.R.L.
CY - Paris
AN - OPUS4-47674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
A1 - Tchetgnia Ngassam, Ines
A1 - Breitschaft, G.
A1 - Virchow, S.
ED - Diouri, A.
ED - Boukhari, A.
ED - Ait Brahim, L.
ED - Bahi, L.
ED - Khachani, N.
ED - Saadi, M.
ED - Aride, J.
ED - Nounah, A.
T1 - Challenges of the growing African cement market – environmental issues, regulative framework, and quality infrastructure requirements
N2 - The African cement, concrete and construction business is growing at rapid pace. The cement sales are expected to grow rapidly until 2050. The number of newly built cement plants increases dramatically and in addition more cements are being imported from outside the continent, e.g. from Turkey, Pakistan, Indonesia, and China, driven by overcapacities in the countries of origin. This causes a high number of potentials and challenges at the same time. Newly built cement plants can operate directly at best technological state of the art and thus incorporate more sustainable technologies as well as produce new and more sustainable products such as cements blended with sustainable supplementary cementitious materials such as calcined clays, and industrial or agricultural by products. At the same time the new variety of binding agent as well as the international imports, which are driven by price considerations, make the cement market prone to quality scatter. This puts pressure on the quality control regulations and institutions to ensure safety of construction, healthy application, and environmental safety for the population. The paper presents possible solutions to build up the rapidly increasing African cement production more sustainably than in the rest of the world as well as the related challenges and obstacles that need to be overcome. Based on experiences with a series of pan-African cement testing laboratory proficiency schemes conclusions are made on technical, regulative and political level.
T2 - 2nd International Congress on Materials & Structural Stability (CMSS-2017)
CY - Rabat, Morocco
DA - 22.11.2017
KW - Quality Infrastructure
KW - Africa
KW - Proficiency Testing
KW - Cement
KW - Admixtures
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444330
DO - https://doi.org/10.1051/matecconf/201814901014
SN - 2261-236X
VL - 149
SP - 01014-1
EP - 01014-8
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-44433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmidt, Wolfram
A1 - Kühne, Hans-Carsten
A1 - Leinitz, Sarah
ED - Diouri, A.
ED - Boukhari, A.
ED - Ait Brahim, L.
ED - Bahi, L.
ED - N., Khachani
ED - Saadi, M
ED - Aride, J.
ED - Nounah, A.
T1 - Concrete casting robustness improvement due to active rheology
N2 - With ongoing innovation in process technology, the challenges of concrete technology are more and more focused on the rheological optimisation for these processes, since improper mixture stability or poor compaction ability negatively affect the concrete homogeneity and quality. However, along with the increasing complexity of today’s concrete mixture compositions, concrete becomes more prone to failure regarding the casting process. Variable properties of the raw materials typically cause changing workability. The reasons can be found among others in scattering water contents, physical or chemical properties of the cement or varying environmental temperatures. Robustness in the delicately adjusted rheology, however, is of utmost importance for modern and future process technology, from sprayed concrete over pumpable concrete towards 3D-printing, with regard to the long-term strength, the function and the durability. Typically, material induced changes cannot be identified easily due to the complex interactions of concrete constituents. Therefore, a precise and prompt counteraction is impossible. However, it is known that the yield stress can be controlled by addition of supplementary superplasticizer or stabilising agent. In combination with computerized process observation tools that can rapidly interpret and react on changes in the rheology, it is therefore thinkable, that only these two admixture types can adjust the rheology steadily and permanently, regardless of the actual root cause for observed macroscopic rheology change. The presentation will firstly give a comprehensive overview of effects at the interface between pore solution, particles and hydrates, which affect the rheology of fresh concrete. Secondly, ways are recommended how the rheology can be actively manipulated before eventually computerized methods are demonstrated that help to actively and rapidly assess and counteract performance scatter during steady casting processes.
T2 - 2nd International Congress on Materials & Structural Stability (CMSS-2017)
CY - Rabat, Morocco
DA - 22.11.2017
KW - Cusum
KW - Rheology
KW - Control Chart
KW - Concrete
KW - Robustness
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444317
DO - https://doi.org/10.1051/matecconf/201814901001
SN - 2261-236X
VL - 149
SP - 01001-1
EP - 01001-7
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-44431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shamsuddoha, Md
A1 - Hüsken, Götz
A1 - Schmidt, Wolfram
A1 - Kühne, Hans-Carsten
A1 - Baeßler, Matthias
T1 - Superplasticizer and Shrinkage Reducing Admixture Dosages for Microfine Cement in Grout Systems
N2 - Grouts have numerous applications including crack repair as maintenance in construction industries. Microfine cements are intensively used for high strength mortar and grout products. They are ideal for injection grouting in structural repair. Such grouts should have suitable rheological properties to be injectable, especially those used in repair and rehabilitation. The use of superplasticizers (SP) in these products is thus becoming increasingly crucial to achieve favorable workability and viscosity properties. A difficulty in such grouts is the plastic shrinkage due to finer particles used. It is thus necessary to determine optimum SP and shrinkage reducing admixture (SRA) dosages for a microfine cement based grout. In this study, a saturation dosage was decided from two Polycarboxylate ether (PCE) based SPs in relation to neat cement using slump flow and rheological parameters. A range of grout mixtures was formulated containing micro silica (MS) and fly ash (FA), and tested for suitable rheological and mechanical parameters. Based on the results, a grout mixture with MS and FA was selected to determine optimum SRA content. According to the results, a SP dosage of 3% by weight of neat cement is sufficient to achieve saturation. The grout material including MS and FA can produce comparable properties to neat cement grout. MS is found to improve compressive strength within the range considered, whereas a higher FA content provides favourable rheological properties. Finally, a SRA dosage of 4%, which could reduce the shrinkage by about 43% after 28d days, is determined for the grout system.
T2 - 2nd International Conference on Building Materials and Materials Engineering (ICBMM 2018)
CY - University of Lisbon, Portugal
DA - 26.09.2018
KW - Grout
KW - Microfine Cement
KW - Superplasticizer
KW - Supplementary Cementitious Materials
KW - Shrinkage Reducing Admixture
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-478319
DO - https://doi.org/10.1051/matecconf/201927801001
VL - 278
SP - Article Number 01001
PB - EDP Sciences
AN - OPUS4-47831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shamsuddoha, Md
A1 - Hüsken, Götz
A1 - Schmidt, Wolfram
A1 - Kühne, Hans-Carsten
A1 - Baeßler, Matthias
ED - Alexander, M.G.
ED - Beushausen, H.
ED - Dehn, F.
ED - Moyo, P.
T1 - Workability and mechanical properties of ultrafine cement based grout for structural rehabilitation: A parametric study on the partial replacement with SCMs
N2 - Grouting is a universal repair and strengthening technique, which is constantly used for structural remediation of concrete components, trenches, mine subsidence, dam joints, restoration of masonry structures, and geological stabilizations. Having an extremely small particle size of only few microns, ultrafine cements are ideal for grouting applications due to their superior permeability and compressive strength properties of the hardened cement paste compared to that of the less-expensive, but coarser ordinary Portland cements. Supplementary cementitious materials (SCMs) are often used to replace ultrafine cement in order to modify certain properties and to reduce costs. The aim of this experimental study is to investigate the effect of three supplementary materials: microsilica (MS), fly ash (FA), and metakaolin (MK) on the workability, and mechanical properties of an ultrafine cement based grout with a constant water-binder ratio and constant superplasticizer content. Maximum percentages of replacement with ultrafine cement were 6% by volume of cement for MS and 16% for FA, and MK. In general, results suggest that the workability is improved by addition of FA, whereas is reduced, when modified with MS and MK. The compressive strength of grout after cement replacement remains comparable to that of pure cement grout. However, there is a tendency of the MS to positively affect the compressive strength opposite to FA, whereas flexural strength is positively affected by FA. Based on the results, it is evident that grouts with Hägerman cone flow more than 500 mm and compressive strength of more than 90 MPa after 28 days can be produced.
T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018)
CY - Cape Town, South Africa
DA - 19.11.2018
KW - Grouting
KW - Repair
KW - Box-Behnken
KW - Supplementary cementitious materials
KW - Analysis of variance
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464769
DO - https://doi.org/10.1051/matecconf/201819907006
SN - 2261-236X
VL - 199
SP - 07006-1
EP - 07006-7
PB - MATEC Web of Conferences
AN - OPUS4-46476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Schmidt, Wolfram
T1 - Analyse von Schallemissionen bei Zugversuchen an hochduktilem Beton
N2 - Hochduktiler Beton eröffnet neue Möglichkeiten bei der Instandsetzung von Bauwerken, der Herstellung dünnwandiger Bauelemente oder dem Einsatz von Dämpfungselementen in stoßartig beanspruchten Bauwerken (z.B. in Erdbebengebieten).
Die Steigerung der Duktilität kann durch die Zugabe von Kurzfasern erreicht werden. Im Falle einer Rissbildung in der Zementsteinmatrix überbrücken die Fasern den Riss, nehmen die Spannung vollständig auf und stoppen lokal das Risswachstum. Bei weiterer Steigerung der Last reißt die Matrix an anderer Stelle. Auf diese Weise wird die Rissbildung fein verteilt und es werden große Dehnungen erreicht, bevor das Bauteil versagt. Zur Optimierung der Festbetoneigenschaften müssen die Matrixfestigkeit und die Faserart sowie deren Gehalt aufeinander abgestimmt werden. Dabei sind auch die Verarbeitungseigenschaften des Frischbetons zu berücksichtigen.
Anhand der Schallemissionen kann die Rissbildung in der Matrix und die Interaktion mit den Fasern analysiert werden. So konnte in ersten Zugversuchen gezeigt werden, dass sich Schallereignisse dem Versagen der Zementsteinmatrix bzw. dem Auszug der Fasern aus der Matrix zuordnen lassen. Damit steht zur Beurteilung des mechanischen Verhaltens von hochduktilem Beton neben der Spannungs-Dehnungs-Linie ein weiteres Verfahren zur Verfügung.
T2 - 20. Kolloquium Schallemission - Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse
CY - Garmisch-Partenkirchen, Germany
DA - 18.06.2015
KW - SHCC
KW - Hochduktiler Beton
KW - Schallemission
KW - Zugversuch
KW - PVA-Fasern
KW - Faserverstärkter Beton
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331920
SN - 978-3-940283-73-3
IS - DGZfP-BB 153
SP - Vortrag 4, 1
EP - 7
AN - OPUS4-33192
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haist, M.
A1 - Link, J.
A1 - Nicia, D.
A1 - Leinitz, Sarah
A1 - Baumert, C.
A1 - von Bronk, T.
A1 - Cotardo, D.
A1 - Eslami Pirharati, M.
A1 - Fataei, S.
A1 - Garrecht, H.
A1 - Gehlen, C.
A1 - Hauschildt, I.
A1 - Ivanova, I.
A1 - Jesinghausen, S.
A1 - Klein, C.
A1 - Krauss, H.-W.
A1 - Lohaus, L.
A1 - Lowke, D.
A1 - Mazanec, O.
A1 - Pawelczyk, S.
A1 - Pott, U.
A1 - Radebe, N. W.
A1 - Riedmiller, J. J.
A1 - Schmid, H.-J.
A1 - Schmidt, Wolfram
A1 - Secrieru, E.
A1 - Stephan, D.
A1 - Thiedeitz, M.
A1 - Wilhelm, M.
A1 - Mechtcherine, V.
T1 - Interlaboratory study on rheological properties of cement pastes and reference substances: comparability of measurements performed with different rheometers and measurement geometries
N2 - This paper presents the results of an interlaboratory study of the rheological properties of cement paste and ultrasound gel as reference substance. The goal was to quantify the comparability and reproducibility of measurements of the Bingham parameters yield stress and plastic viscosity when measured on one specific paste composition and one particular ultrasound gel in different laboratories using different rheometers and measurement geometries.
The procedures for both in preparing the cement paste and carrying out the rheological measurements on cement paste and ultrasound gel were carefully defined for all of the study’s participants. Different conversion schemes for comparing the results obtained with the different measurement setups are presented here and critically discussed. The procedure proposed in this paper ensured a reasonable comparability of the results with a coefficient of variation for the yield stress of 27% and for the plastic viscosity of 24%, despite the individual measurement series’ having been performed in different labs with different rheometers and measurement geometries.
KW - Rheometry
KW - Rheology
KW - Interlaboratory test
KW - Test setup
KW - Testing procedure
KW - Cement paste
KW - Ultrasound gel
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511220
DO - https://doi.org/10.1617/s11527-020-01477-w
SN - 1871-6873
VL - 53
IS - 4
SP - 92
PB - Rilem
AN - OPUS4-51122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lorenzoni, Renata
A1 - Fritsch, Tobias
A1 - Kruschwitz, Sabine
A1 - Bruno, Giovanni
A1 - Schmidt, Wolfram
T1 - Mechanical analysis of cement-biochar composites using in-situ X-ray microtomography and digital volume correlation
N2 - This study addresses biochar as a potential carbon-sequestering filler in cement and examines its effect on mechanical properties using X-ray computed tomography (XCT) and digital volume correlation (DVC). DVC was reliably used to measure global displacement and has proven to be an effective method for correcting displacement data obtained from mechanical tests conducted without traditional instrumentation, such as extensometer. This made it possible to measure strain and Young’s modulus accurately. The results demonstrate that while 5 vol% biochar replacement had minimal effect on mechanical properties, a 25 vol% biochar replacement caused a 35 % reduction in Young’s modulus and 40 % reduction in the ultimate compressive strength. Additionally, DVC detected strain concentrations and predicted material failure locations even when cracks could not be quantified using XCT alone. Moreover, the study reveals that biochar particles, due to their sharp geometry, increase internal shear strain during uniaxial compression, unlike round phases such as pores.
KW - Cementitious materials
KW - Biochar
KW - Mechanical proprieties
KW - In-situ X-ray microtomography
KW - Digital volume correlation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638065
DO - https://doi.org/10.1016/j.conbuildmat.2025.142511
SN - 1879-0526
VL - 490
PB - Elsevier Ltd.
AN - OPUS4-63806
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andresen, Elina
A1 - Islam, Fahima
A1 - Prinz, Carsten
A1 - Gehrmann, P.
A1 - Licha, K.
A1 - Roik, Janina
A1 - Recknagel, Sebastian
A1 - Resch-Genger, Ute
T1 - Assessing the reproducibility and up‑scaling of the synthesis of Er,Yb‑doped NaYF4‑based upconverting nanoparticles and control of size, morphology, and optical properties
N2 - Lanthanide-based, spectrally shifting, and multi-color luminescent upconverting nanoparticles (UCNPs) have received much attention in the last decades because of their applicability as reporter for bioimaging, super-resolution microscopy, and sensing as well as barcoding and anti-counterfeiting tags. A prerequisite for the broad application of UCNPs in areas such as sensing and encoding are simple, robust, and easily upscalable synthesis protocols that yield large quantities of UCNPs with sizes of 20 nm or more with precisely controlled and tunable physicochemical properties from lowcost reagents with a high reproducibility. In this context, we studied the reproducibility, robustness, and upscalability of the synthesis of β-NaYF4:Yb, Er UCNPs via thermal decomposition. Reaction parameters included solvent, precursor chemical compositions, ratio, and concentration. The resulting UCNPs were then examined regarding their application-relevant physicochemical properties such as size, size distribution, morphology, crystal phase, chemical composition, and photoluminescence.
Based on these screening studies, we propose a small volume and high-concentration synthesis approach that can provide UCNPs with different, yet controlled size, an excellent phase purity and tunable morphology in batch sizes of up to at least 5 g which are well suited for the fabrication of sensors, printable barcodes or authentication and recycling tags.
KW - Photoluminescence
KW - Nano
KW - Nanomaterial
KW - Synthesis
KW - Reproducibility
KW - Upconversion nanoparticle
KW - Lanthanide
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570170
DO - https://doi.org/10.1038/s41598-023-28875-8
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 13
AN - OPUS4-57017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nguyen, H. G.
A1 - Toman, B.
A1 - van Zee, R.
A1 - Prinz, Carsten
A1 - Thommes, M.
A1 - Ahmad, R.
A1 - Kiska, D.
A1 - Salinger, J.
A1 - Walton, I.
A1 - Walton, K.
A1 - Broom, D.
A1 - Benham, M.
A1 - Ansari, H.
A1 - Pini, R.
A1 - Petit, C.
A1 - Adolphs, J.
A1 - Schreiber, A.
A1 - Shigeoka, T.
A1 - Konishi, Y.
A1 - Nakai, K.
A1 - Henninger, M.
A1 - Petrzik, T.
A1 - Kececi, C.
A1 - Martis, V.
A1 - Paschke, T.
A1 - Mangano, E.
A1 - Brandani, S.
T1 - Reference isotherms for water vapor sorption on nanoporous carbon: results of an interlaboratory study
N2 - This paper reports the results of an international interlaboratory study sponsored by the Versailles Project on Advanced Materials and Standards (VAMAS) and led by the National Institute of Standards and Technology (NIST) on the measurement of water vapor sorption isotherms at 25 °C on a pelletized nanoporous carbon (BAM-P109, a certified reference material). Thirteen laboratories participated in the study and contributed nine pure water vapor isotherms and four relative humidity isotherms, using nitrogen as the carrier gas. From these data, reference isotherms, along with the 95% uncertainty interval (Uk=2), were determined and are reported in a tabular format.
KW - BAM-P109
KW - Interlaboratory study
KW - Nanoporous carbon
KW - Reference isotherm
KW - VAMAS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576560
DO - https://doi.org/10.1007/s10450-023-00383-1
SN - 0929-5607
SP - 1
EP - 12
PB - Springer
CY - Heidelberg
AN - OPUS4-57656
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dayani, Shahabeddin
A1 - Markötter, Henning
A1 - Krug von Nidda, Jonas
A1 - Schmidt, Anita
A1 - Bruno, Giovanni
T1 - Quantification of the Deep Discharge Induced Asymmetric Copper Deposition in Lithium‐Ion Cells by Operando Synchrotron X‐Ray Tomography
N2 - AbstractLithium‐ion cells connected in series are prone to an electrical safety risk called overdischarge. This paper presents a comprehensive investigation of the overdischarge phenomenon in lithium‐ion cells using operando nondestructive imaging. The study focuses on understanding the behavior of copper dissolution and deposition during overdischarge, which can lead to irreversible capacity loss and internal short‐circuits. By utilizing synchrotron X‐ray computed tomography (SXCT), the concentration of dissolved and deposited copper per surface area is quantified as a function of depth of discharge, confirming previous findings. The results also highlight for the first time a nonuniform distribution pattern for copper deposition on the cathode. This research provides insights for safer battery cell design.
KW - Lithium Ion Batteries
KW - Deep Discharge
KW - Computer Tomography
KW - Copper Deposition
KW - Litium Ion Cells
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592717
DO - https://doi.org/10.1002/admt.202301246
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-59271
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Halisch, M.
A1 - Dlugosch, R.
A1 - Prinz, Carsten
T1 - Toward a better understanding of low-frequency electrical relaxation - An enhanced pore space characterization
N2 - Relaxation phenomena observed in the electrical low-frequency range (approximately 1 mHz-10 kHz) of natural porous media like sandstones is often assumed to be directly related to the dominant (modal) pore throat sizes measured, for instance, with mercury intrusion porosimetry. Attempts to establish a universally valid relationship between pore size and peak Spectral Induced Polarization (SIP) relaxation time have failed, considering sandstones from very different origins and featuring great variations in textural and chemical compositions as well as in geometrical pore space properties. In addition working with characteristic relaxation times determined in Cole-Cole or Debye decomposition fits to build the relationship have not been successful. In particular, samples with narrow pore throats are often characterized by long SIP relaxation times corresponding to long “characteristic length scales” in these media, assuming that the diffusion coefficients along the electrical double layer were constant. Based on these observations, three different types of SIP relaxation can be distinguished. We present a new way of assessing complex pore spaces of very different sandstones in a multi-methodical approach to combine the benefits of mercury intrusion porosimetry, micro-computed tomography, and nuclear magnetic resonance. In this way, we achieve much deeper insight into the pore space due to the different resolutions and sensitivities of the applied methods to both pore constrictions (throats) and wide pores (pore bodies). We experimentally quantify pore aspect ratios and volume distributions within the two pore regions. We clearly observe systematic differences between three SIP relaxation types identified previously and can attribute the SIP peak relaxation times to measured characteristic length scales within our materials. We highlight selected results for a total of nine sandstones. It seems that SIP relaxation behavior depends on the size difference of the narrow pore throats to the wide pore bodies, which increases from SIP Type 1 to Type 3.
KW - µ-CT
KW - Spectral induced polarization
KW - Nuclear magnetic resonance
KW - Pore space
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509763
DO - https://doi.org/10.1190/GEO2019-0074.1
SN - 0016-8033
VL - 85
IS - 4
SP - MR257
EP - MR270
PB - Society of Exploration Geophysicists
AN - OPUS4-50976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Redda, Zinnabu T.
A1 - Brennecke, Daniel
A1 - Prinz, Carsten
A1 - Yimam, Abubeker
A1 - Barz, Mirko
A1 - Kadow, Steffen
A1 - Laß-Seyoum, Asnakech
T1 - Synthesis and characterization of AlPO4-18 supported mesoporous and crystalline β-Mo2C, Ni3C, and WC nanoparticles
N2 - Developing high-efficiency, high-stability, and low-cost deoxygenation and hydrocracking catalysts could be considered one of the most significant breakthroughs in catalytic hydroprocessing. The present study utilized aluminophosphate (AlPO4-18), a zeolite-like molecular sieve, as catalyst support for producing carbon-coated β-Mo2C, Ni3C, and WC nanoparticles. The synthesis used an incipient wetness impregnation followed by a temperature-programmed reduction-carburization approach which involved cracking a hydrocarbon gas, propane, in a hydrogen environment. The synthesis parameters were a 1:7 propane/hydrogen reductive-carburizing gas stream, 15 wt.% metal loading, an 800 °C carburization temperature ramped-up at a heating rate of 10 °C min−1, a 2-h holding time, and a 1-h holding time in hydrogen. The synthesized catalysts were characterized using thermogravimetry mass spectroscopy/temperature-programmed oxidation (TPO TG-MS), nitrogen physisorption at 77 K, X-ray diffraction (XRD), and transmission electron microscopy/energy-dispersive X-ray spectroscopy (TEM EDS). TPO TG-MS, nitrogen physisorption, TEM, and XRD characterization results proved that atomic carbon was successfully incorporated into the lattice interstitials, resulting in thermally stable, well-dispersed, crystalline and mesoporous β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18 nanoparticles. XRD analysis showed structural evolution during reduction-carburization, with average crystallite sizes of metal-containing particles of 8.2–9.22, 6.64–8.50, and 6.03–7.56 nm for β-Mo2C/AlPO4-18, Ni3C/AlPO4-18, and WC/AlPO4-18, respectively. These values did not significantly deviate from high-resolution TEM analysis. The surface areas of the nanoparticles were categorized in decreasing order as WC/AlPO4-18 > Ni3C/AlPO4-18 > β-Mo2C/AlPO4-18, with values of 193.79, 169.05, and 66.57 m2 g−1, respectively. In conclusion, these carbon-coated metal carbide nanoparticles with excellent thermal, structural, microscopic, and textural properties can be viable alternatives to noble metal catalysts for producing bio-jet fuel using the hydroprocessing pathway.
KW - Catalyst synthesis
KW - Temperature-programmed reduction-carburization
KW - Catalyst characterization
KW - BET surface area
KW - Nanoparticle
KW - Transition metal carbide catalyst
KW - TEM
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608182
DO - https://doi.org/10.1007/s10562-024-04791-y
SN - 1011-372X
SN - 1572-879X
VL - 154
SP - 5969
EP - 5988
PB - Springer Science and Business Media
CY - Dordrecht
AN - OPUS4-60818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Nils
A1 - Dayani, Shahabeddin
A1 - Markötter, Henning
A1 - Bau, Alexander
A1 - Setzchen, Max
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Krug von Nidda, Jonas
T1 - High Precision Nail‐Penetration Setup for the Controlled Thermal Runaway Initiation of Lithium‐Ion Cells at Very Low Temperatures
N2 - A high precision nail‐penetration (NP) tool for characterizing the mechanically induced thermal‐runaway (TR) of lithium‐ion battery (LIB) cells in a defined range of temperatures down to −140 °C was developed. To understand the cell specific behavior at low temperatures aiming at the determination of safe handling conditions, different scenarios are analyzed. First, accuracy tests of the NP‐tool regarding motion and penetration depth are conducted with cylindrical cells at different temperatures. Thus, postmortem computer tomographic (CT) images are compared to the data measured with the newly integrated 3‐axis force sensor which is further combined with a high‐resolution position sensor. The herein developed setup allows evaluation of the NP‐metrics at an accuracy of ±1 pierced electrode layer without CT‐scans. Further NP examinations at 20 °C of fully charged cylindrical lithium nickel manganese cobalt oxide cells reveal a reproducible minimum damage as a reliable TR‐trigger. Moreover, NP‐tests at low temperature disclose a relation of the short circuit conductivity and TR‐reactions during subsequent rethermalization to room temperature. Finally, the implementation of a novel fixture for a controlled very fast cooling of LIB‐cells during critical damage opens the way to investigate the individual steps during a TR and, thus, to gain important information of the specific TR‐mechanism of different LIB‐cells.
KW - Battery Safety
KW - High-precision nail penetration
KW - Lithium-ion batteries
KW - Abuse testing
KW - Thermal runaway
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598127
DO - https://doi.org/10.1002/ente.202301379
SN - 2194-4288
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-59812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoogendoorn, Levi
A1 - Huertas, Mauricio
A1 - Nitz, Phillip
A1 - Qi, Naiyu
A1 - Baller, Johannes
A1 - Prinz, Carsten
A1 - Graeber, Gustav
T1 - Sustainable, Low‐Cost Sorbents Based on Calcium Chloride‐Loaded Polyacrylamide Hydrogels
N2 - AbstractSorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high‐performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high‐performance, cost‐efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The achievable salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel‐salt composites are shown to be stable under repeated sorption‐desorption cycling and enable water uptakes of 0.92 and 2.38 grams of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost‐performance ratio substantially exceeds lithium chloride‐based systems. Further, the mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low‐cost sorbent materials for future applications in water and energy.
KW - Electrochemistry
KW - Condensed Matter Physics
KW - Biomaterials
KW - Electronic, Optical and Magnetic Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598366
DO - https://doi.org/10.1002/adfm.202314680
SN - 1616-301X
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Leonhardt, Robert
A1 - Böttcher, Nils
A1 - Dayani, Shahabeddin
A1 - Rieck, Arielle
A1 - Markötter, Henning
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Tichter, Tim
A1 - Krug von Nidda, Jonas
T1 - Exploring the electrochemical and physical stability of lithium-ion cells exposed to liquid nitrogen
N2 - The transport and storage of lithium-ion (Li-ion) batteries — damaged or in an undefined state — is a major safety concern for regulatory institutions, transportation companies, and manufacturers. Since (electro)chemical reactivity is exponentially temperature-dependent, cooling such batteries is an obvious measure for increasing their safety.
The present study explores the effect of cryogenic freezing on the electrochemical and physical stability of Li-ion cells. For this purpose, three different types of cells were repeatedly exposed to liquid nitrogen (LN2).
Before and after each cooling cycle, electrical and electrochemical measurements were conducted to assess the impact of the individual freezing steps. While the electrochemical behavior of the cells did not change significantly upon exposure to LN2 , it became apparent that a non-negligible number of cells suffered from physical changes (swelling) and functional failures. The latter defect was found to be caused by the current interrupt device of the cylindrical cells. This safety mechanism is triggered by the overpressure of expanding nitrogen which enters the cells at cryogenic temperatures.
This study underlines that the widely accepted reversibility of LN2 -cooling on a material scale does not allow for a direct extrapolation toward the physical integrity of full cells. Since nitrogen enters the cell at cryogenic temperatures and expands upon rethermalization, it can cause an internal overpressure. This can, in turn, lead to mechanical damage to the cell. Consequently, a more appropriate temperature condition — less extreme than direct LN2 exposure — needs to be found
KW - Lithium-ion battery
KW - LN2 cooling
KW - Battery characterization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599248
DO - https://doi.org/10.1016/j.est.2024.111650
VL - 89
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-59924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grimmer, Christoph
A1 - Richter, Matthias
A1 - Neuhaus, T.
A1 - Prinz, Carsten
A1 - Strzelczyk, Rebecca Skadi
A1 - Colakoglu, Irem
A1 - Horn, Wolfgang
T1 - Towards a multi-VOC emission reference material with temporally constant emission profile for QA/QC of materials emission testing procedures
N2 - Emission reference materials (ERMs) are sought after to further control and improve indoor air quality. The impregnation of porous materials with volatile organic compounds (VOCs) is a promising approach to produce ERMs. Different VOCs were used to impregnate various porous materials (mainly zeolites, activated carbons and a metal organic framework). The influence of different methodological parameters and material properties were studied to optimize the impregnation procedure and to find the best material/VOC combination. The impregnation procedure remains quite irreproducible, nevertheless, very good ERM candidates were identified. Two materials (zeolite 4 and AC 1 impregnated with n-hexadecane) showed a very stable emission over 14 days (<10 % change). Another material (AC 1 impregnated with toluene) showed a declining emission profile but with a very good in-batch reproducibility and a storage stability of up to 12 months.
KW - Emission reference material
KW - Porous materials
KW - Indoor air quality
KW - Emission test chamber
KW - CO2 assisted impregnation
KW - EN 16516
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612238
DO - https://doi.org/10.1016/j.chemosphere.2024.143437
SN - 1879-1298
VL - 366
SP - 1
EP - 8
PB - Elsevier
AN - OPUS4-61223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Nils
A1 - Dayani, Shahabeddin
A1 - Markötter, Henning
A1 - Schmidt, Anita
A1 - Kowal, J.
A1 - Lu, Y.
A1 - Krug von Nidda, Jonas
A1 - Bruno, Giovanni
T1 - Visualization of stepwise electrode decomposition in a nail penetrated commercial lithium-ion cell using low-temperature synchrotron X-ray computed tomography
N2 - The transition towards zero carbon emissions in power generation hinges on the integration of efficient electrical energy storage systems, with lithium-ion batteries (LIBs) positioned as a pivotal technology. While generally safe, deviations in their operational guidelines due to manufacturing defects or misuse can lead to critical safety concerns, notably thermal runaway (TR) events. Internal short circuits (ISCs) are primary initiators of TR within LIBs. For abuse testing, ISCs are often triggered by nail penetration. This study explores the morphological changes and mechanisms underlying ISC-induced TR in LIBs using operando synchrotron X-ray computed tomography (SXCT) at subzero temperatures. A novel cryogenic setup was developed to control a stepwise temperature increase in the damaged sample while monitoring electrochemical characteristics and simultaneously enabling acquisition of high-resolution SXCT images. The findings reveal that conducting nail penetration at minus 80°C prevents immediate TR, enabling detailed analysis of subsequent structural and electrochemical behavior during controlled thawing. Thus, the initiation of TR processes at localized ISC sites has been observed, evidenced by voltage fluctuations and morphological changes, such as cathode material cracking and decomposition. These results underscore the importance of temperature control in mitigating TR risks and provide critical insights into the internal dynamics of LIBs under abusive conditions. The developed cryogenic SXCT methodology offers a powerful tool for non-destructive, high-resolution investigation of battery failure mechanisms, contributing to the enhancement of LIB safety.
KW - Tomography
KW - X-ray imaging
KW - Lithium-ion battery
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611327
DO - https://doi.org/10.1016/j.jpowsour.2024.235472
VL - 623
SP - 1
EP - 10
PB - Elsevier
CY - New York, NY
AN - OPUS4-61132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiodjio Sendja, Bridinette
A1 - Tchouank Tekou, Carol Trudel
A1 - Prinz, Carsten
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Adsorptive performance of single-walled carbon nanotubes for divalent manganese sorption characterized by X-ray absorption spectroscopy
N2 - The adsorptive performance of divalent manganese onto single-walled carbon nanotubes (SWCNTs) is investigated by X-ray absorption spectroscopy (XAS). The study is focused on the one hand, on the use of SWCNT as adsorbent to remove divalent manganese II) pollutant controlling batch parameters such as pH, adsorbent dose and contact time; and on the other hand, on the characterization of manganese adsorbed by SWCNT (Mn-SWCNT) adsorbent to probe the chemical composition, oxidation state, and local structural environment of Mn absorber. Freundlich adsorption isotherm well fitted the experimental data and suggested the maximum adsorption capacity at pH 2. Ion exchange was proposed as the main adsorption mechanism for removing manganese using SWCNT. XAS results revealed the change in the oxidation state of manganese. The effect of pH, adsorbent dose, and contact time is shown. XAS also showed that Mn-SWCNT material is principally composed of MnCl2, Mn2O3, MnO2, Mn3O4, and MnO in decreasing order with MnCl2 and Mn2O3 as major compounds.
KW - Local environment
KW - Single-walled carbon nanotubes
KW - Divalent manganese
KW - Adsorptive performance
KW - X-ray absorption spectroscopy
KW - Oxidation state
PY - 2025
DO - https://doi.org/10.1007/s11696-025-04418-5
SN - 0366-6352
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-64492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gong, Mengjun
A1 - Mehmood, Asad
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Fellinger, Tim-Patrick
A1 - Jackson, Colleen
A1 - Cui, Junyi
A1 - Drazic, Goran
A1 - Kucernak, Anthony
T1 - Designing Co–N/C Cathode Catalysts with Dense Atomic Cobalt Sites for Enhanced PEMFC Performance
N2 - Metal-nitrogen/carbon (M-N/C) catalysts, particularly those incorporating Fe,Co, or Mn, are among the most promising non-platinum group catalysts forthe acidic oxygen reduction reaction (ORR) in fuel cells. This study reports aCo-N/C catalyst featuring high (3 wt%) cobalt content exclusively present asatomic sites. Extended X-ray absorption fine structure analysis confirms atetrapyridinic Co-N4 coordination environment in the optimized (3.0)Co-N/C𝚫catalyst. The high cobalt loading leads to a significant density ofelectrochemically accessible active sites, 3.58 × 10 19 sites g−1 , quantified viathe nitrite stripping method. The catalyst demonstrates excellent ORR activityin a rotating ring-disk electrode setup, achieving a half-wave potential (E 1/2 ) of0.76 V at a low loading of 0.2 mg cm−2 and a mass activity of 3.5 A g−1 at 0.80VRHE . Single-cell hydrogen-oxygen PEMFC tests achieve a peak power densityexceeding 1.3 W cm−2 (iR-corrected). Under hydrogen-air condition, thecatalyst delivers 0.54 A cm−2 at 0.60 V (0.39 W cm−2 ). Despite the intrinsicallyhigher turnover frequency of Fe-based sites, the optimized(3.0)Co-N/C𝚫 catalyst achieves similar fuel cell performance to that of Fe-N/C,highlighting the critical role of site density in overall activity.
KW - Fuel cells
KW - Single atom catalysts
KW - Oxygen reduction reaction
KW - Non-precious catalysts
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644276
DO - https://doi.org/10.1002/advs.202516060
SN - 2198-3844
SP - 1
EP - 11
PB - Wiley VHC-Verlag
AN - OPUS4-64427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böttcher, Nils
A1 - Sander, Luise
A1 - Ulbricht, Alexander
A1 - Widjaja, Martinus Putra
A1 - Fellinger, Tim-Patrick
A1 - Schmidt, Anita
A1 - Krug von Nidda, Jonas
T1 - Sodium-ion battery research @ BAM (I): investigating the thermal runaway behaviour of commercial sodium-ion battery cells
N2 - Commercially available sodium-ion battery (SIB) cells, with energy densities comparable to lithium-ion battery (LIB) cells based on LiFePO4, were investigated regarding their safety behaviour under thermal abuse conditions. Tests were carried out in an inert atmosphere. The SIB-cells went into thermal runaway (TR), intriguingly, even at a rather low state of charge of 30%. The TR-event was coupled with a pronounced jelly roll ejection, challenging the interpretation of the TR-diagrams. These findings highlight the necessity of incorporating SIB-cells into the ongoing safety classification discussions for LIB-cells.
KW - Sodium Ion Batteries
KW - Thermal Runaway
KW - Battery safety
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647652
DO - https://doi.org/10.1039/d5se00687b
SN - 2398-4902
VL - 9
IS - 21
SP - 5832
EP - 5838
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Habibimarkani, Heydar
A1 - Abram, Sarah-Luise
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Prinz, Carsten
A1 - Sahre, Mario
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - In-depth analysis of FeNi-based nanoparticles for the oxygen evolution reaction
N2 - This study investigates the effect of varying iron-to-nickel ratios on the catalytic performance of Fe-Ni oxide nanoparticles (NPs) for the oxygen evolution reaction (OER). Addressing the issue of high energy wastage due to large overpotentials in OER, we synthesized and characterized different NP catalysts with different Fe: Ni oxide ratios. Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Spectroscopy (EDS), and X-ray Diffraction (XRD) were employed to determine the morphology, elemental and phase composition of the NPs. Furthermore, in-depth profiling with X-ray Photoelectron Spectroscopy (XPS) and Hard X-ray Photoelectron Spectroscopy (HAXPES) revealed that iron predominantly exists as oxide, while nickel exhibits both metallic and oxidic forms depending on the Fe content. XPS indicated an enrichment of iron at the NP surface, whereas HAXPES and EDS data agreed on the bulk stoichiometry. The assessment of the catalytic activity via cyclic voltammetry (CV) showed that the Fe: Ni ratio of 2:3 exhibited superior performance, characterized by lower overpotential and a smaller Tafel slope.
KW - Fe-Ni oxide
KW - Nanoparticles
KW - OER
KW - Catalytic performance
KW - Cyclic voltammetry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626932
UR - https://www.nature.com/articles/s41598-025-92720-3
DO - https://doi.org/10.1038/s41598-025-92720-3
VL - 15
IS - 1
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-62693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharpmann, Philippa
A1 - Leonhardt, Robert
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Tichter, Tim
A1 - Krug von Nidda, Jonas
T1 - Exploring restrictive overdischarge cycling as a method to accelerate characteristic ageing in lithium-ion cells
N2 - This study presents a test protocol that greatly accelerates the ageing process of lithium-ion battery cells comprising a positive electrode of nickel manganese cobalt oxide while preserving their characteristic degradation upon cyclic ageing. Applying a repetitive restricted overdischarge, resulting in a depth of discharge larger than 100%, a capacity loss of 20% is achieved over five times faster compared to conventional cycling. The well-known overdischarge degradation phenomenon of copper current collector dissolution is deliberately prevented by setting a discharge cutoff voltage above the theoretical threshold of copper oxidation. Hence, the accelerated degradation can be primarily connected to solid electrolyte interphase growth.
A comparative assessment of the ageing dynamics using electrochemical impedance spectroscopy and differential voltage analysis hints towards similar, characteristic degradation processes during accelerated and conventional ageing. A post-ageing examination of the electrical behaviour (i.e., coulombic and energy efficiency, capacity fade) under reference conditions reveals very little to no lasting damages caused by
overdischarging. Additionally, post-mortem analysis discloses no increased copper dissolution when comparing cells subjected to accelerated and conventional ageing. Generally, the developed ageing method appears suitable for providing cells with a defined state of health at a reasonable timescale without altering the main degradation mechanisms significantly.
KW - Lithium-ion cell
KW - Accelerated ageing
KW - Overdischarge
KW - Degradation processes
KW - Differential voltage analysis
KW - Electrochemical impedance spectroscopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650917
DO - https://doi.org/10.1016/j.jpowsour.2025.239072
SN - 0378-7753
VL - 665
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavasolyzadeh, Zeynab
A1 - Tang, Peng
A1 - Hahn, Marc Benjamin
A1 - Hweidi, Gada
A1 - Nordholt, Niclas
A1 - Haag, Rainer
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - 2D and 3D Micropatterning of Mussel‐Inspired Functional Materials by Direct Laser Writing
N2 - AbstractThis work addresses the critical need for multifunctional materials and substrate‐independent high‐precision surface modification techniques that are essential for advancing microdevices and sensing elements. To overcome existing limitations, the versatility of mussel‐inspired materials (MIMs) is combined with state‐of‐the‐art multiphoton direct laser writing (DLW) microfabrication. In this way, 2D and 3D MIM microstructures of complex designs are demonstrated with sub‐micron to micron resolution and extensive post‐functionalization capabilities. This study includes polydopamine (PDA), mussel‐inspired linear, and dendritic polyglycerols (MI‐lPG and MI‐dPG), allowing their direct microstructure on the substrate of choice with the option to tailor the patterned topography and morphology in a controllable manner. The functionality potential of MIMs is demonstrated by successfully immobilizing and detecting single‐stranded DNA on MIM micropattern and nanoarray surfaces. In addition, easy modification of MIM microstructure with silver nanoparticles without the need of any reducing agent is shown. The methodology developed here enables the integration of MIMs in advanced applications where precise surface functionalization is essential.
KW - Direct laser writing
KW - Mussel-inspired materials
KW - Polyglycerol
KW - Polydopamine
KW - Micropatterning
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588778
DO - https://doi.org/10.1002/smll.202309394
SN - 1613-6829
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-58877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fankhänel, J.
A1 - Silbernagl, Dorothee
A1 - Ghasem Zadeh Khorasani, Media
A1 - Daum, B.
A1 - Kempe, A.
A1 - Sturm, Heinz
A1 - Rolfes, R.
T1 - Mechanical properties of Boehmite evaluated by Atomic Force Microscopy experiments and Molecular Dynamic Finite Element simulations
N2 - Boehmite nanoparticles show great potential in improving mechanical properties of fiber reinforced polymers. In order to predict the properties of nanocomposites, knowledge about the material parameters of the constituent phases, including the boehmite particles, is crucial. In this study, the mechanical behavior of boehmite is investigated using Atomic Force Microscopy (AFM) experiments and Molecular Dynamic Finite Element Method (MDFEM) simulations. Young’s modulus of the perfect crystalline boehmite nanoparticles is derived from numerical AFM simulations. Results of AFM experiments on boehmite nanoparticles deviate significantly. Possible causes are identified by experiments on complementary types of boehmite, that is, geological and hydrothermally synthesized samples, and further simulations of imperfect crystals and combined boehmite/epoxy models. Under certain circumstances, the mechanical behavior of boehmite was found to be dominated by inelastic effects that are discussed in detail in the present work.The studies are substantiated with accompanying X-ray diffraction and Raman experiments.
KW - AFM
KW - MDFEM
KW - Nanocomposite
KW - Epoxy
KW - X-ray diffraction
KW - Raman spectroscopy
KW - Young’s modulus
KW - Slippage of weakly linked layers
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-384230
UR - https://www.hindawi.com/journals/jnm/2016/5017213/#B26
DO - https://doi.org/10.1155/2016/5017213
VL - 2016
IS - Article ID 5017213
SP - 1
EP - 13
PB - Hindawi Publishing Corporation
AN - OPUS4-38423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Meyer, Susann
A1 - Schröter, Maria-Astrid
A1 - Seitz, H.
A1 - Kunte, Hans-Jörg
A1 - Solomun, Tihomir
A1 - Sturm, Heinz
T1 - Direct electron irradiation of DNA in fully aqueous environment. Damage determination in combination with Monte Carlo simulations
N2 - We report on a study in which plasmid DNA in water was irradiated with 30 keV electrons generated by a scanning electron microscope and passed through a 100 nm thick Si3N4 membrane. The corresponding Monte Carlo simulations suggest that the kinetic energy spectrum of the electrons throughout the water is dominated by low energy electrons (<100 eV). The DNA radiation damage, single-strand breaks (SSB) and double-strand breaks (DSB), was determined by electrophoresis. The median lethal dose of D1/2 = 1.7 ± 0.3 Gy was found to be much smaller compared to partially or fully hydrated DNA irradiated under vacuum conditions. The ratio of DSB to SSB was found to be (1:12) as compared to 1:88) found for hydrated DNA. Our method enables quantitative measurements of radiation damage to biomolecules (DNA, proteins) in solutions under varying conditions (pH, salinity, cosolutes) for an electron energy range which is difficult to probe by standard methods.
KW - Plasmid DNA in water
KW - Monte Carlo simulation
KW - Low energy electrons
KW - DNA radiation damage
KW - Single-strand break (SSB)
KW - Double-strand break (DSB)
KW - Lethal dose
KW - Radiation damage to biomolecules
KW - Solutions (pH, salinity, cosolutes)
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-386981
DO - https://doi.org/10.1039/C6CP07707B
SN - 1463-9076
SN - 1463-9084
VL - 19
IS - 3
SP - 1798
EP - 1805
PB - Royal Society of Chemistry
AN - OPUS4-38698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Meyer, Susann
A1 - Kunte, Hans-Jörg
A1 - Solomun, Tihomir
A1 - Sturm, Heinz
T1 - Measurements and simulations of microscopic damage to DNA in water by 30 keV electrons: A general approach applicable to other radiation sources and biological targets
N2 - The determination of the microscopic dose-damage relationship for DNA in an aqueous environment is of a fundamental interest for dosimetry and applications in radiation therapy and protection. We combine geant4 particle-scattering simulations in water with calculations concerning the movement of biomolecules to obtain the energy deposit in the biologically relevant nanoscopic volume. We juxtaposition these results to the experimentally determined damage to obtain the dose-damage relationship at a molecular level. This approach is tested for an experimentally challenging system concerning the direct irradiation of plasmid DNA (pUC19) in water with electrons as primary particles. Here a microscopic target model for the plasmid DNA based on the relation of lineal energy and radiation quality is used to calculate the effective target volume. It was found that on average fewer than two ionizations within a 7.5-nm radius around the sugar-phosphate backbone are sufficient to cause a single strand break, with a corresponding median lethal energy deposit being E1/2=6±4 eV. The presented method is applicable for ionizing radiation (e.g., γ rays, x rays, and electrons) and a variety of targets, such as DNA, proteins, or cells.
KW - DNA
KW - Radiation damage
KW - Dosimetry
KW - DNA radiation damage
KW - Single-strand break (SSB)
KW - Double-strand break (DSB)
KW - Low energy electrons
KW - Monte Carlo simulation
KW - Radiation damage to biomolecules
KW - Plasmid DNA in water
KW - Lethal dose
KW - Solutions (pH, salinity, cosolutes)
KW - Geant4
KW - Microdosimetry
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404244
DO - https://doi.org/10.1103/PhysRevE.95.052419
SN - 2470-0045
SN - 2470-0053
VL - 95
IS - 5
SP - 052419-1
EP - 052419-8
PB - American Physical Society
CY - USA
AN - OPUS4-40424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Susann, Meyer
A1 - Schröter, Maria-Astrid
A1 - Kunte, Hans-Jörg
A1 - Solomun, Tihomir
A1 - Sturm, Heinz
T1 - DNA protection by ectoine from ionizing radiation: molecular mechanisms
N2 - Ectoine, a compatible solute and osmolyte, is known to be an effective protectant of biomolecules and whole cells against heating, freezing and extreme salinity. Protection of cells (human keratinocytes) by ectoine against ultraviolet radiation has also been reported by various authors, although the underlying mechanism is not yet understood. We present the first electron irradiation of DNA in a fully aqueous environment in the presence of ectoine and at high salt concentrations. The results demonstrate effective protection of DNA by ectoine against the induction of single-strand breaks by ionizing radiation. The effect is explained by an increase in low-energy electron scattering at the enhanced free-vibrational density of states of water due to ectoine, as well as the use of ectoine as an ˙OH-radical scavenger. This was demonstrated by Raman spectroscopy and electron paramagnetic resonance (EPR).
KW - Ectoine
KW - DNA
KW - Radiation protection
KW - Ionizing radiation
KW - Compatible solute
KW - Biomolecules
KW - Sodium chloride
KW - Aqueous solution
KW - Hydroxyectoine
KW - Raman spectroscopy
KW - Electron irradiation
KW - Cancer
KW - Radical scavenger
KW - Low energy electrons
KW - Hydroxyl radical
KW - OH-radical
KW - Ectoin
KW - UV radiation
KW - Sun
KW - Salt
KW - Radiation therapy
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419332
UR - http://pubs.rsc.org/en/content/articlehtml/2017/cp/c7cp02860a
DO - https://doi.org/10.1039/C7CP02860A
SN - 1463-9076
VL - 19
IS - 37
SP - 25717
EP - 25722
PB - Royal Society of Chemistry
CY - United Kingdom
AN - OPUS4-41933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stajanca, Pavol
A1 - Mihai, L.
A1 - Sporea, D.
A1 - Negut, D.
A1 - Sturm, Heinz
A1 - Schukar, Marcus
A1 - Krebber, Katerina
ED - Webb, D. J.
ED - Scully, P.
ED - Sugden, K.
T1 - Impacts of gamma irradiation on cytop plastic optical fibres
N2 - Impact of gamma radiation on transmission of a commercial Cytop polymer optical fibre (Lucina, Asahi Glass Company) is investigated. Spectral dependence of radiation induced attenuation in the investigated fibre is measured in the VIS-NIR spectral region. Besides attenuation increase, radiation is found to increase fibre susceptibility to water as well. While pristine Cytop fibre is rather humidity insensitive, strong humidity related absorption in the NIR region is observed after fibre irradiation. Selective irradiation of separate fibre sections is proposed as a way of fibre humidity sensitization and quasi-distributed water detection is demonstrated using optical time domain reflectometry at 1310 nm.
T2 - POF 2016: 25th International Conference on Plastic Optical Fibres
CY - Birmingham, UK
DA - 13.09.2016
KW - Polymer optical fibers
KW - Cytop
KW - Gamma radiation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403216
SN - 9781854494085
SP - 114
EP - 117
CY - Birmingham
AN - OPUS4-40321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröter, Maria-Astrid
A1 - Ritter, M.
A1 - Holschneider, M.
A1 - Sturm, Heinz
T1 - Enhanced DySEM imaging of cantilever motion using artificial structures patterned by focused ion beam techniques
N2 - We use a dynamic scanning electron microscope (DySEM) to map the spatial distribution of the vibration of a cantilever beam. The DySEM measurements are based on variations of the local secondary electron signal within the imaging electron beam diameter during an oscillation period of the cantilever. For this reason, the surface of a cantilever without topography or material variation does not allow any conclusions about the spatial distribution of vibration due to a lack of dynamic contrast. In order to overcome this limitation, artificial structures were added at defined positions on the cantilever surface using focused ion beam lithography patterning. The DySEM signal of such high-contrast structures is strongly improved, hence information about the surface vibration becomes accessible. Simulations of images of the vibrating cantilever have also been performed. The results of the simulation are in good agreement with the experimental images.
KW - FIB patterning
KW - Structured cantilever
KW - AFM
KW - Modal analysis
KW - DySEM
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354510
DO - https://doi.org/doi:10.1088/0960-1317/26/3/035010
VL - 26
IS - 3
SP - 035010-1
EP - 035010-7
AN - OPUS4-35451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
A1 - Uhlig, F.
A1 - Solomun, Tihomir
A1 - Smiatek, J.
A1 - Sturm, Heinz
T1 - Combined influence of ectoine and salt: spectroscopic and numerical evidence for compensating effects of aqueous solutions
N2 - Ectoine is an important osmolyte, which allows microorganisms to survive in extreme environmental salinity. The hygroscopic effects of ectoine in pure water can be explained by a strong water binding behavior whereas a study on the effects of ectoine in salty solution is yet missing. We provide Raman spectroscopic evidence that the influence of ectoine and NaCl are opposing and completely independent of each other. The effect can be explained by the formation of strongly hydrogen-bonded water molecules around ectoine which compensate the influence of the salt on the water dynamics. The mechanism is corroborated by first principles calculations and broadens our understanding of zwitterionic osmolytes in aqueous solution. Our findings allow us to provide a possible explanation for the relatively high osmolyte concentrations in halotolerant bacteria.
KW - Ectoine
KW - Aqueous solution
KW - Biological structure
KW - Organic osmolytes
KW - Raman spectroscopy
KW - Water structure
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376761
UR - http://pubs.rsc.org/en/content/articlelanding/2016/cp/c6cp05417j#!divAbstract
DO - https://doi.org/10.1039/c6cp05417j
VL - 18
IS - 41
SP - 28398
EP - 28402
PB - Royal Society of Chemistry
CY - UK
AN - OPUS4-37676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - THES
A1 - Dümichen, Erik
T1 - Einsatz neuer thermoanalytischer Verfahren zur Untersuchung thermischer und thermo-oxidativer Degradationsmechanismen sowie dem Netzwerkaufbau von Polymeren
N2 - Die Anwendung thermoanalytischer Methoden für die Polymercharakterisierung hat aufgrund der makromolekularen Struktur von Polymere Vorteile. Es wurden zwei neue thermoanalyti-sche Verfahren entwickelt und deren Einsatz anhand von Anendungsbeispielen demons-triert, sowie mit etablierten, thermoanalytischen Methoden verglichen.
Für die thermische- und thermo-oxidative Zersetzungsgasanalytik wurde die Thermogravi-metrie (TGA) gekoppelt mit der Thermodesoptions-Gaschromatographie-Massenspektrometrie (TDS-GC-MS). Die Zersetzungsgase der TGA wurden dafür über ei-nen Festphasenadsorber geleitet, auf dem eine repräsentative Auswahl von polymerspezifi-schen Analyten adsorbiert wurde. Die thermische Extraktion der Analyten erfolgte in der TDS-GC-MS. Dies ermöglichte die Trennung der Analyten sowie die eindeutige Identifizie-rung mittels charakteristischer Massenfragmentmuster. Sie wurde als TED-GC-MS bezeichnet. Es stellte sich heraus, dass sie sich besonders für die Analyse von komplexen Kohlen-wasserstoffgemischen mit Molmassen von mehr als 100 g/mol eignet. In Kombination mit anderen Kopplungstechniken wie beispielsweise die TGA-FTIR/MS, die speziell für die Ana-lyse von kleineren Molekülen verwendet wurde, konnten neue grundlegende Zersetzungs-mechanismen entwickelt werden. Es wurde beispielsweise sichtbar, dass sowohl bei der thermischen als auch bei der thermo-oxidativen Degradation von Polyamid 66 (PA 66) Kon-densationsreaktionen eine wichtige Rolle spielen. Die Methode erwies sich darüber hinaus als besonders geeignet für die Identifizierung und Quantifizierung von Polymeren in Umweltproben. Es entstand dazu eine erste grundlegende Arbeit für die quantitative Bestimmung von Polyethylen (PE) Mikroplastik in Umweltproben.
Im zweiten Teil der Arbeit wurde eine steuerbare beheizbare Zelle eingeführt. Mit ihr war es möglich, mit Hilfe der Nahinfrarotspektroskopie (NIR), sich verändernde Netzwerkstrukturen während der Härtung sichtbar zu machen. Vergleichend dazu wurden etablierte, kalorische Messungen durchgeführt. Somit konnten für verschiedene Epoxidsysteme die Aushärtegrade während der Härtung mit variablen Heizraten bestimmt werden. Dadurch konnten Aushär-tungskinetiken erstellt werden, die durch isotherme und komplexe Aushärtungsszenarien validiert wurden.
KW - Thermische Methoden
KW - Polymer
KW - Analytik
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:188-fudissthesis000000100982-9
UR - http://www.diss.fu-berlin.de/diss/receive/FUDISS_thesis_000000100982
SP - 1
EP - 65
PB - FU Berlin
CY - Berlin
AN - OPUS4-42171
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breitenbach, Romy
A1 - Silbernagl, Dorothee
A1 - Toepel, J.
A1 - Sturm, Heinz
A1 - Broughton, William J.
A1 - Sassaki, G. L.
A1 - Gorbushina, Anna
T1 - Corrosive extracellular polysaccharides of the rock-inhabiting model fungus Knufia petricola
N2 - Melanised cell walls and extracellular polymeric matrices protect rock-inhabiting microcolonial fungi from hostile environmental conditions. How extracellular polymeric substances (EPS) perform this protective role was investigated by following development of the model microcolonial black fungus Knufia petricola A95 grown as a sub-aerial biofilm. Extracellular substances were extracted with NaOH/formaldehyde and the structures of two excreted polymers studied by methylation as well as NMR analyses. The main polysaccharide (~ 80%) was pullulan, also known as α-1,4-; α-1,6-glucan, with different degrees of polymerisation. Αlpha-(1,4)-linked-Glcp and α-(1,6)-linked-Glcp were present in the molar ratios of 2:1. A branched galactofuromannan with an α-(1,2)-linked Manp main chain and a β-(1,6)-linked Galf side chain formed a minor fraction (~ 20%). To further understand the roles of EPS in the weathering of minerals and rocks, viscosity along with corrosive properties were studied using atomic force microscopy (AFM). The kinetic viscosity of extracellular K. petricola A95 polysaccharides (≈ 0.97 × 10-6 m2 s-1) ranged from the equivalent of 2% (w/v) to 5% glycerine, and could thus profoundly affect diffusion-dominated processes. The corrosive nature of rock-inhabiting fungal EPS was also demonstrated by its effects on the aluminium coating of the AFM cantilever and the silicon layer below.
KW - Corrosion
KW - EPS
KW - Melanised microcolonial fungi (MCF)
KW - Pullulan
KW - Sub-aerial biofilms (SAB)
KW - α-1,4- and α-1,6-glucans
KW - AFM cantilever vibration
KW - Nanoviscosity
KW - Nanocorrosion of aluminium and silicon
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435910
DO - https://doi.org/10.1007/s00792-017-0984-5
SN - 1433-4909
SN - 1431-0651
VL - 22
IS - 2
SP - 165
EP - 175
PB - Springer
CY - Berlin
AN - OPUS4-43591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Platz, D.
A1 - Sturm, Heinz
T1 - Insights into Nano-Scale Physical and Mechanical Properties of Epoxy/Boehmite Nanocomposite Using Different AFM Modes
N2 - Understanding the interaction between nanoparticles and the matrix and the properties of interphase is crucial to predict the macroscopic properties of a nanocomposite system. Here, we investigate the interaction between boehmite nanoparticles (BNPs) and epoxy using different atomic force microscopy (AFM) approaches. We demonstrate benefits of using multifrequency intermodulation AFM (ImAFM) to obtain information about conservative, dissipative and van der Waals tip-surface forces and probing local properties of nanoparticles, matrix and the interphase.
We utilize scanning kelvin probe microscopy (SKPM) to probe surface potential as a tool to visualize material contrast with a physical parameter, which is independent from the mechanics of the surface. Combining the information from ImAFM stiffness and SKPM surface potential results in a precise characterization of interfacial region, demonstrating that the interphase is softer than epoxy and boehmite nanoparticles. Further, we investigated the effect of boehmite nanoparticles on the bulk properties of epoxy matrix. ImAFM stiffness maps revealed the significant stiffening effect of boehmite nanoparticles on anhydride-cured epoxy matrix. The energy Dissipation of epoxy Matrix locally measured by ImAFM shows a considerable increase compared to that of neat epoxy. These measurements suggest a substantial alteration of epoxy structure induced by the presence of boehmite.
KW - Nanomechanics
KW - Intermodulation-AFM
KW - Interphase
KW - Boehmite
KW - Epoxy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476040
DO - https://doi.org/10.3390/polym11020235
SN - 2073-4360
VL - 11
IS - 2
SP - 235, 1
EP - 19
PB - MDPI
AN - OPUS4-47604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Rivard, C.
A1 - Wilken, V.
A1 - Muskolus, A.
A1 - Adam, Christian
T1 - Performance of secondary P-fertilizers in pot experiments analyzed by phosphorus X-ray absorption near-edge structure (XANES) spectroscopy
N2 - A pot experiment was carried out with maize to determine the phosphorus (P) plant-availability of different secondary P-fertilizers derived from wastewater. We analyzed the respective soils by P K-edge X-ray absorption near-edge structure (XANES) spectroscopy to determine the P chemical forms that were present and determine the transformation processes. Macro- and micro-XANES spectroscopy were used to determine the chemical state of the overall soil P and identify P compounds in P-rich spots. Mainly organic P and/or P adsorbed on organic matter or other substrates were detected in unfertilized and fertilized soils. In addition, there were indications for the formation of ammonium phosphates in some fertilized soils. However, this effect was not seen in the maize yield of all P-fertilizers. The observed reactions between phosphate from secondary P-fertilizers and cofertilized nitrogen compounds should be further investigated. Formation of highly plant-available compounds such as ammonium phosphates could make secondary P-fertilizers more competitive to commercial phosphate rock-based fertilizers with positive effects on resources conservation.
KW - Phosphorus
KW - Pot experiments
KW - Secondary P-fertilizer
KW - Sewage sludge ash
KW - Soil
KW - X-ray absorption near-edge structure (XANES) spectroscopy
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-433782
DO - https://doi.org/10.1007/s13280-017-0973-z
SN - 0044-7447
VL - 47
IS - 1
SP - 62
EP - 72
PB - Springer
AN - OPUS4-43378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröter, Maria-Astrid
A1 - Meyer, Susann
A1 - Hahn, Marc Benjamin
A1 - Solomun, Tihomir
A1 - Sturm, Heinz
A1 - Kunte, Hans-Jörg
T1 - Ectoine protects DNA from damage by ionizing radiation
N2 - Ectoine plays an important role in protecting biomolecules and entire cells against environmental stressors such as salinity, freezing, drying and high temperatures. Recent studies revealed that ectoine also provides effective protection for human skin cells from damage caused by UV-A radiation. These protective properties make ectoine a valuable compound and it is applied as an active ingredient in numerous pharmaceutical devices and cosmetics. Interestingly, the underlying mechanism resulting in protecting cells from radiation is not yet fully understood. Here we present a study on ectoine and its protective influence on DNA during electron irradiation. Applying gel electrophoresis and atomic force microscopy, we demonstrate for the first time that ectoine prevents DNA strand breaks caused by ionizing electron radiation. The results presented here point to future applications of ectoine for instance in cancer radiation therapy.
KW - Plasmid DNA pUC19
KW - Electron irradiation 30 [kV]
KW - Effective irradiation dose 0.2-16 [Gy]
KW - Gel electrophoresis
KW - AFM intermittent contact
KW - Radioprotector ectoine
KW - Compatible solute
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428287
DO - https://doi.org/10.1038/s41598-017-15512-4
SN - 2045-2322
VL - 7
IS - 1
SP - 15272, 1
EP - 15272, 7
PB - Nature
AN - OPUS4-42828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Redfern, J.
A1 - Tucker, J.
A1 - Simmons, L.
A1 - Askew, P.
A1 - Verran, J.
A1 - Stephan, Ina
T1 - Environmental and experimental factors affecting efficacy testing on nonporous plastic antimicrobial surfaces
N2 - Test methods for efficacy assessment of antimicrobial coatings are not modelled on a hospital environment, and instead use high humidity (>90%) high temperature (37 ◦C), and no airflow. Therefore, an inoculum will not dry, resulting in an antimicrobial surface exhibiting prolonged antimicrobial activity, as moisture is critical to activity. Liquids will dry quicker in a hospital ward, resulting in a reduced antimicrobial efficacy compared to the existing test, rendering the test results artificially favourable to the antimicrobial claim of the product. This study aimed to assess how hospital room environmental conditions can affect the drying time of an inoculum, and to use this data to inform test parameters for antimicrobial efficacy testing based on the hospital ward. The drying time of different droplet sizes, in a range of environmental conditions likely found in a hospital ward, were recorded (n = 630), and used to create a model to inform users of the experimental conditions required to provide a drying time similar to what can be expected in the hospital
ward. Drying time data demonstrated significant (p < 0.05) variance when humidity, temperature, and airflow were assessed. A mathematical model was created to select environmental conditions for in vitro antimicrobial efficacy testing. Drying time in different environmental conditions demonstrates that experimental set-ups affect the amount of time an inoculum stays wet, which in turn may affect the efficacy of an antimicrobial surface. This should be an important consideration for hospitals and other potential users, whilst future tests predict efficacy in the intended end-use environment.
KW - Method development
KW - Standardisation
KW - Antimicrobial test
KW - Environmental conditions
KW - Hospital premises
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472699
DO - https://doi.org/10.3390/mps1040036
SN - 2409-9279
VL - 1
IS - 4
SP - 36, 1
EP - 10
PB - MDPI
CY - Internet open accsess
AN - OPUS4-47269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Sabine
A1 - Niederleithinger, Ernst
A1 - Bohlen, T.
T1 - Reverse time migration: a seismic imaging technique applied to synthetic ultrasonic data
N2 - Ultrasonic echo testing is a more and more frequently used technique in civil engineering to investigate concrete building elements, to measure thickness as well as to locate and characterise built-in components or inhomogeneities. Currently the Synthetic Aperture Focusing Technique (SAFT), which is closely related to Kirchhoff migration, is used in most cases for imaging. However, this method is known to have difficulties to image steeply dipping interfaces as well as lower boundaries of tubes, voids or similar objects. We have transferred a processing technique from geophysics, the Reverse Time Migration (RTM) method, to improve the imaging of complicated geometries. By using the information from wide angle reflections as well as from multiple events there are fewer limitations compared to SAFT. As a drawback the required computing power is significantly higher compared to the techniques currently used. Synthetic experiments have been performed on polyamide and concrete specimens to show the improvements compared to SAFT. We have been able to image vertical interfaces of step-like structures as well as the lower boundaries of circular objects. It has been shown that RTM is a step forward for ultrasonic testing in civil engineering.
KW - Beton
KW - Ultraschall
KW - Concrete
KW - Imaging
KW - Ultrasonics
KW - Reverse time migration
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-262952
DO - https://doi.org/10.1155/2012/128465
SN - 1687-8868
SN - 1687-885X
VL - 2012
IS - Article ID 128465
SP - 1
EP - 7
PB - Hindawi Publishing Corporation
CY - New York, NY, USA
AN - OPUS4-26295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Kupsch, Andreas
T1 - Numerische Korrektur des Hinterleuchtens von Röntgendetektoren
N2 - Eine neuartige Korrektur artefaktisch gemessener Intensitäten von Röntgenflachdetektoren wird vorgeschlagen. Die betrachteten Artefakte betreffen eine diffuse Umverteilung der Intensität und führen zu beträchtlichen Verfälschungen der wahren Schwächung und verletzen mithin das Lambert-Beer'sche Gesetz.
Sie werden sowohl in Laborexperimenten mit Röntgenröhren (polychromatische Einstrahlung) als auch mit monochromatischer Synchrotronstrahlung bei Einsatz indirekt konvertierender Detektionssysteme (Fluoreszenzschirm, Optik, CCD-Chip) beobachtet.
Dieser Effekt wird als Hinterleuchten bezeichnet.
In der vorgestellten Studie werden mittels wohldefinierter Randbedingungen Gesetzmäßigkeiten des Hinterleuchtens untersucht: durch Einsatz monochromatischer Strahlung können Aufhärtungseffekte als Ursache ausgeschlossen werden. Das Hinterleuchten ist umso stärker ausgeprägt, je weniger Detektorfläche vom Objekt abdeckt wird und je stärker das Objekt schwächt. Mit Blick auf Tomographien ergibt sich eine Modulation der 'Dichte' als Funktion des Projektionswinkels, deren Amplitude mit dem Objektumfang steigt (Dynamik).
Der isotrope und homogene Ansatz zur numerischen Korrektur macht lediglich Gebrauch von Intensitätsmittelwerten und stellt die Gültigkeit des Schwächungsgesetzes in modifizierter Form wieder her.
T2 - DACH-Jahrestagung 2012
CY - Graz, Austria
DA - 17.09.2012
KW - Röntgendetektor
KW - Hinterleuchten
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-277372
SN - 978-3-940283-44-3
IS - DGZfP-BB 136
SP - P 13 / Mo.4.B, 1
EP - 7
AN - OPUS4-27737
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Werner
A1 - Wöhlecke, Andreas
T1 - Influence of rib stiffness and limited long-term junction strength on geogrid performance
N2 - The description of the behavior of geogrids in reinforced soil constructions usually ignores long-term behavior and possible failure modes of junctions between longitudinal and transverse ribs. Two proposals have been made during recent years to overcome this drawback. The first analytic approach applies only to rigid geogrids and assumes a specific tensile-shear failure mode of geogrid junctions. The second numerical approach applies also for non-rigid geogrids and takes into account different modes of junction failure. This note discusses the two approaches focusing on the effects of rib stiffness and limited strength, different failure modes and degradation of junctions. It is shown that the mentioned effects should be considered in geogrid design, because they may alter significantly the long-term geogrid performance.
KW - Geogrid
KW - Junction
KW - Anchor trench
KW - Design rules
KW - Long-term behavior
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637076
DO - https://doi.org/10.1007/s40515-019-00095-6
SN - 2196-7202
VL - 7
IS - 2
SP - 175
EP - 190
PB - Springer
CY - New York, NY
AN - OPUS4-63707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Leers, K.
A1 - Arnold, U.
A1 - Herzel, Hannes
A1 - Adam, Christian
A1 - Burkhardt, J.
T1 - Thermochemically Treated Sewage Sludge Ash From Pilot-Scale Production as P-Fertilizer for Spring Wheat and Maize in Different Soil Conditions
N2 - Background
P-fertilizers made from sewage sludge ash (SSA) may be suitable substitutes for rock phosphate (RP)-based fertilizers and contribute to sustainable use of waste. In this context, the thermochemical AshDec treatment of SSA (TC-SSA) has been continuously improved and has emerged as a possible method to produce plant-available and low-pollutant P-fertilizers. Aim Evaluation of the P-fertilizer efficacy of TC-SSA produced in pilot trials in vegetation experiments with different plants, soils, and fertilizer doses.
Methods
TC-SSA was tested in pot experiments for spring wheat and maize on different soils and at two doses (0.2 and 0.4 g fertilizer P pot−1) and is compared to untreated SSA (USSA), RP, Struvite, triple superphosphate (TSP), and a control without P-fertilization (Zero P). Pot experiments are complemented by an analysis of fertilizer P-solubility.
Results
P-solubility of SSA with different extraction methods increased due to the thermochemical treatment, whereas the water-insoluble property remained. In contrast to RP or USSA, TC-SSA enriched calcium–acetate–lactate extractable soil P to the same extent as TSP. Plant biomass and P-uptake increased with TC-SSA compared to Zero P, RP, and USSA and were in most cases equal to TSP fertilization under different soil conditions. In contrast, the effects of RP and USSA varied among soils but, mostly, did not exceed plant biomass and P-uptake of the unfertilized control.
Conclusion
TC-SSA has an increased fertilizer efficacy compared to USSA and is an effective P-fertilizer for spring wheat and maize in different soil conditions.
KW - Phosphorus
KW - Fertilizer
KW - Thermochemical
KW - Maize
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648251
DO - https://doi.org/10.1002/jpln.70035
SN - 1522-2624
VL - 189
IS - 1
SP - 81
EP - 93
PB - Wiley-VCH
AN - OPUS4-64825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madbouly, Loay Akmal
A1 - Sturm, Heinz
A1 - Doolin, Alexander
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Chemical Analysis of Commercial Functionalized Graphene Nanoplatelets along the Production Process with Raman Spectroscopy and X-ray Photoelectron Spectroscopy
N2 - Commercial applications increasingly rely on functionalized graphene nanoplatelets (GNPs) supplied as powders, aqueous suspensions, and printable inks, yet their process−structure−property relationships across the production chain remain to be fully mapped. Here we apply a correlative Raman spectroscopy (Raman) and X-ray photoelectron spectroscopy (XPS) workflow to nine independent industrial graphene batches spanning three surface chemistries, raw (R), fluorinated (F), and nitrogen-functionalized (N), in all three physical forms which are powders, suspensions, and inks.
Raman mapping (with a 532 nm excitation laser) showed that I2D/IG is highest for N samples and lowest for R-ink. A 2D-vs-G correlation places all samples on a trajectory parallel to the pure-doping vector, which can correlate to holes in the graphene lattice. The mean point-defect spacing is LD = 8.4−10.0 nm. High-resolution XPS resolves the accompanying chemical changes: F-powder exhibits distinct C−F (289 eV), C−F2 (292 eV), and C−F3 (293 eV) components and loses roughly half its F content upon dispersion in deionized water or ink formulation; inks of all chemistries show a pronounced O−C=O peak near 289−290 eV originated from the ink compounds. N-functionalized samples showed a prominent C−N (285.5 eV) only for the ink formulated N-functionalized sample. This study establishes a process-aware blueprint linking the functionalization route and formulation step to lattice disorder and surface chemistry, offering transferable quality-control metrics for graphene supply chains in industrial products/applications such as coatings, storage devices, and printed electronics.
KW - Functionalized graphene
KW - Raman Spectroscopy
KW - XPS
KW - Chemical analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652548
DO - https://doi.org/10.1021/acs.jpcc.5c06820
SN - 1932-7447
VL - 129
IS - 50
SP - 22033
EP - 22040
PB - American Chemical Society (ACS)
AN - OPUS4-65254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jovičević-Klug, Matic
A1 - Souza Filho, Isnaldi R.
A1 - Springer, Hauke
A1 - Adam, Christian
A1 - Raabe, Dierk
T1 - Green steel from red mud through climate-neutral hydrogen plasma reduction
N2 - AbstractRed mud is the waste of bauxite refinement into alumina, the feedstock for aluminium production1. With about 180 million tonnes produced per year1, red mud has amassed to one of the largest environmentally hazardous waste products, with the staggering amount of 4 billion tonnes accumulated on a global scale1. Here we present how this red mud can be turned into valuable and sustainable feedstock for ironmaking using fossil-free hydrogen-plasma-based reduction, thus mitigating a part of the steel-related carbon dioxide emissions by making it available for the production of several hundred million tonnes of green steel. The process proceeds through rapid liquid-state reduction, chemical partitioning, as well as density-driven and viscosity-driven separation between metal and oxides. We show the underlying chemical reactions, pH-neutralization processes and phase transformations during this surprisingly simple and fast reduction method. The approach establishes a sustainable toxic-waste treatment from aluminium production through using red mud as feedstock to mitigate greenhouse gas emissions from steelmaking.
KW - Multidisciplinary
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594424
DO - https://doi.org/10.1038/s41586-023-06901-z
SN - 0028-0836
VL - 625
IS - 7996
SP - 703
EP - 709
PB - Springer Science and Business Media LLC
AN - OPUS4-59442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, Sven
A1 - Pauw, Brian Richard
A1 - Weimann, Christiane
A1 - Sturm, Heinz
T1 - First of its kind: A test artifact for direct laser writing
N2 - With femtosecond-laser direct writing (fs-LDW) maturing in all aspects as a manufacturing technology, a toolset for quality assurance must be developed. In this work we introduce a first of its kind test artifact. Test artifacts are standardized 3D models with specific geometric features to evaluate the performance of writing parameters. Test artifacts are already common in other 3D additive manufacturing technologies e.g. selective laser melting. The test artifact introduced in this work was developed in particular to accommodate the high geometrical resolution of fs-LDW structures and the limited possibilities to examine the resulting structure. Geometric accuracy, surface adhesion as well as confocal Raman spectroscopy results were considered when evaluating the design of the test artifact. We will explain the individual features and design considerations of our fs-LDW test artifact. The difference between two slicers, Cura and 3DPoli, and the implications on measured feature sizes and the general shape is quantified. The measured geometries are used to derive a general design guide for a specific combination of photoresists, laser power and scanning speed and to analyze the geometric accuracy of a structure produced using these guidelines. The shown test artifact is publicly available as STL file on GitHub (https://github.com/BAMresearch/2PP-TestArtifact) and in the supplement.
KW - Laser direct writing
KW - Multi photon lithography
KW - Reference material
KW - Raman spectroscopy
KW - Confocal raman imaging
KW - Slicers
KW - Open data on zenodo
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580951
DO - https://doi.org/10.1088/1361-6501/acc47a
VL - 34
IS - 7
SP - 1
EP - 14
PB - IOP Science
AN - OPUS4-58095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
ED - Schraut, Katharina
ED - Adamczyk, Burkart
ED - Adam, Christian
ED - Stephan, D.
ED - Simon, Sebastian
ED - von Werder, Julia
ED - Meng, Birgit
T1 - Production of a hydraulic material from post treated steelmaking slags
N2 - Steelmaking slag is a by-product of steel production, of which 4.5 Mt were produced in 2020 in Germany alone. It is mainly used in road construction, earthwork and hydraulic engineering. A smaller part is returned to the metallurgical cycle, used as fertiliser or landfilled.
With this use, iron oxides still contained in steelmaking slag are lost. In addition, the possibility of producing higher-grade products from steelmaking slag is foregone. In recent decades, many researchers have investigated the production of Portland cement clinker and crude iron from basic oxygen furnace slags (BOFS) via a reductive treatment. Carbothermal treatment of liquid BOFS causes a reduction of iron oxides to metallic iron, which separates from the mineral phase due to its higher density. Simultaneously, the chemical composition of the reduced slag is adapted to that of Portland cement clinker.
In this study, German BOFS was reduced in a small-scale electric arc furnace using petrol coke as a reducing agent. The resulting low-iron mineral product has a similar chemical composition to Portland cement clinker and was rich in the tricalcium silicate solid solution alite (Ca3SiO5). Based on its chemical and mineralogical composition, similar to that of Portland cement clinker, the reduced BOFS has the potential to react comparably. In our study, the reduced BOFS produced less hydration heat than OPC, and its hydraulic reaction was delayed. However, adding gypsum has shown to accelerate the hydration rate of the reduced BOFS compared to that known from the calcium silicates of Portland cement clinker.
Further research to improve the hydraulic properties of the reduced slag is essential. If successful, producing a hydraulic binder and crude iron from BOFS has economic and ecological benefits for both the cement and steel industries.
T2 - The 16th International Congress on the Chemistry of Cement 2023 (ICCC2023)
CY - Bangkok, Thailand
DA - 18.09.2023
KW - Steelmaking slag
KW - Alite
KW - Clinker substitute
KW - Hydraulic reactivity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590522
UR - https://www.iccc-online.org/archive/
SP - 432
EP - 436
CY - Bangkok
AN - OPUS4-59052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholl, Juliane
A1 - Lisec, Jan
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Identification of transformation products from fluorinated lithium-ion battery additives TPFPB and TPFPP: forever chemicals of tomorrow?
N2 - AbstractFluorinated organic compounds (FOCs) represent a class of synthetic chemicals distinguished by their resilient carbon–fluorine bonds, which demonstrate an ability to withstand environmental degradation over an extended period. The integration of FOCs into cutting-edge applications, including lithium-ion batteries (LiBs), presents considerable potential for environmental harm that has not yet been sufficiently addressed. This study focuses on the environmental fate of two fluorinated aromatics, tris(pentafluorophenyl)borane (TPFPB) and tris(pentafluorophenyl)phosphine (TPFPP), given their important role in improving the performance of LiBs. To achieve this, laboratory simulation methods including total oxidizable precursor assay, electrochemistry (EC), Fenton reaction, UV-C irradiation, and hydrolysis were employed. Liquid chromatography and gas chromatography coupled with high-resolution mass spectrometry were used for identification of transformation products (TPs) and prediction of their molecular formulae. Despite the structural similarity between TPFPB and TPFPP, distinct differences in electrochemical behavior and degradation pathways were observed. TPFPB readily underwent hydroxylation and hydrolysis, resulting in a wide range of 49 TPs. A total of 28 TPs were newly identified, including oligomers and highly toxic dioxins. In contrast, TPFPP degraded exclusively under harsh conditions, requiring the development of innovative conditioning protocols for EC. In total, the simulation experiments yielded nine structurally different compounds, including seven previously undescribed, partially defluorinated TPs. This study highlights the potential risks associated with the use of FOCs in LiBs and provides insight into the complex environmental behavior of FOCs.
KW - Mass Spectrometry
KW - LiBs
KW - POPs
KW - Transformation products
KW - Electrochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611339
DO - https://doi.org/10.1007/s00216-024-05526-z
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-61133
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meiers, Emelie
A1 - Scholl, Juliane
A1 - Droas, Morten
A1 - Vogel, Christian
A1 - Leube, Peter
A1 - Sommerfeld, Thomas
A1 - Bagheri, A.
A1 - Adam, Christian
A1 - Seubert, A.
A1 - Koch, Matthias
T1 - Development and evaluation of analytical strategies for the monitoring of per- and polyfluoroalkyl substances from lithium-ion battery recycling materials
N2 - Per- and polyfluoroalkyl substances (PFAS) are well-known as “forever chemicals” and persistent pollutants released by different anthropogenic sources. The potential release of PFAS from accumulating electronic waste and lithium-ion battery (LIB) recycling activities has gained increasing attention in the past years. This creates a need for analytical methods tailored for the determination of PFAS out of environmental matrices related to the named activities or directly out of the concerned materials. In this work, analytical strategies for the monitoring of PFAS in LIB recycling materials were explored for a group of legacy perfluoro sulfonic- and carbonic acids (PFSA and PFCA) and of fluorinated sulfonylimides suspected to be LIB electrolyte ingredients. These analytical strategies comprehend PFAS target approaches with a herein optimized liquid chromatography tandem mass spectrometry (LC–MS/MS) method equipped with a HILIC (hydrophilic interaction liquid chromatography) column in combination with the TOP (total oxidizable precursor) assay and an adapted sample preparation method for high-matrix LIB recycling materials. The validated target method was applied to a set of LIB recycling materials: end-of-life batteries, black masses from hydrometallurgical recycling, and gas absorption solutions from thermal treatment of black masses as part of the recycling procedure. Investigation results show that the LIB industry can be connected to the release of both “LIB”-PFAS, such as the target sulfonylimides, and “already-legacy” PFAS, like the PFSA and PFCA. Especially, the presence of trifluoroacetic acid (TFA) as an emerging pollutant in every investigated LIB material type underlines the threat of PFAS emissions from LIB waste and recycling activities.
KW - Per- and polyfluoroalkyl substances (PFAS)
KW - Battery
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647015
DO - https://doi.org/10.1007/s00216-025-06165-8
SN - 1618-2642
VL - 417
SP - 6567
EP - 6583
PB - Springer Science and Business Media LLC
AN - OPUS4-64701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bonneau, Klara
A1 - Lederer, Jonas
A1 - Templeton, Clark
A1 - Giambagli, Lorenzo
A1 - Rosenberger, David
A1 - Müller, Klaus-Robert
A1 - Clementi, Cecilia
T1 - Peering inside the black box by learning the relevance of many-body functions in neural network potentials
N2 - Machine learned potentials based on artificial neural networks are becoming apopular tool to define an effective energy model for complex systems, either incorporating electronic structure effects at the atomistic resolution, or effectively renormalizing part of the atomistic degrees of freedom at a coarsegrained resolution. One main criticism regarding neural network potentials is that their inferred energy is less interpretable than in traditional approaches, which use simpler and more transparent functional forms. Here we address this problem by extending tools recently proposed in the nascent field of explainable artificial intelligence to coarse-grained potentials based on graph neural networks.With these tools, neural network potentials can be practically decomposed into n-body interactions, providing a human understandable interpretation without compromising predictive power. We demonstrate the approach on three different coarse-grained systems including two fluids (methane and water) and the protein NTL9. The obtained interpretations suggest that well-trained neural network potentials learn physical interactions, which are consistent with fundamental principles.
KW - Neural Network
KW - Explainability
KW - Machine learning potentials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647531
DO - https://doi.org/10.1038/s41467-025-65863-0
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 14
AN - OPUS4-64753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholl, Juliane
A1 - Lisec, Jan
A1 - Bagheri, Abbas
A1 - Meiers, Emelie
A1 - Russo, Francesco Friedrich
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Unveiling aging mechanisms of electrolytes in commercial end-of-life lithium-ion batteries
N2 - In this study, 77 end-of-life (EOL) commercial lithium-ion batteries (LIBs) of various formats were systematically analyzed to investigate electrolyte degradation and the influence of pristine electrolyte compositions on aging behavior. Comprehensive chemical characterization was conducted using targeted and non-targeted mass spectrometry (MS), employing LC-MS/MS, GC-MS, and high-resolution MS (HRMS). This integrated approach enabled the identification of confirmed pristine components and complex degradation products. The results show that rechargeable pouch and cylindrical cells often deviate from conventional model systems, containing mixed lithium salt anions, ionic liquids (ILs), and high concentrations of triflates, triflimides, and bis(fluorosulfonyl)imide (FSI). These function as solvents, salts, or safety-enhancing additives. Specific IL degradation products were identified, and hypotheses formulated on previously unreported pathways. Furthermore, a novel series of oligomerization products of propylene carbonate (PC) was detected. In contrast, non-rechargeable coin cells revealed widespread use of per- and polyfluoroalkyl substances (PFAS) in their original electrolytes. Based on ex situ analyses, hypothetical PFAS degradation mechanisms are proposed here for the first time. The absence of carbonate oligomers and lithium salt-derived products, alongside the presence of standard carbonates, indicates lithium counterion coordination as a key factor in Lewis acid-catalyzed degradation. This study offers valuable insights into real-world battery aging.
KW - Transformation products
KW - Lithium-ion batteries
KW - Fluorinated Compounds
KW - Gas chromatography/ QTOF-MS
KW - HILIC-LC-MS/MS
KW - PFAS
KW - Electrochemistry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644991
DO - https://doi.org/10.1016/j.jpowsour.2025.238613
SN - 0378-7753
VL - 661
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-64499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falkenberg, Rainer
A1 - Kamachali, Reza Darvishi
T1 - Segregation-induced hydrogen embrittlement in titanium
N2 - Although titanium offers an optimal combination of strength, low weight, and toughness for various applications, it suffers from a drawback: loss of ductility upon exposure to hydrogen. In this work, we couple CALPHAD-integrated density-based thermodynamic modelling of hydrogen segregation with an experimentally calibrated fracture model to investigate its on crack propagation in titanium. Here we propose to model the crack propagation path as a quasi-interface with slightly opened structure and reduced atomic density, enabling interstitial hydrogen segregation. The atomic density is then directly linked with the damage parameter. We found that hydrogen segregation in titanium undergoes a significant transition such that above a threshold of only few atomic percent hydrogen in the solid solution, the interfacial hydrogen concentration exceeds 20 at.%. Integrating this information into our fracture model, the material damage evolution could be explained by a segregation-affected Griffith crack energy, resulting in material decohesion. We found that the segregation transition and subsequent embrittlement effects are critically sensitive to the temperature in the system. The present results suggest a mechanism underlying the sudden loss of fracture toughness during crack propagation, in relation to the ductile-to-brittle transition observed in titanium alloys exposed to hydrogen. The proposed CALPHAD-integrated chemo-mechanical framework can be further generalised for studying more complex failure mechanisms in various materials.
KW - Segregation transition
KW - Hydrogen embrittlement
KW - Titanium alloys
KW - Crack propagation
KW - Ductile-to-brittle transition
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655451
DO - https://doi.org/10.1016/j.mtla.2025.102411
SN - 2589-1529
VL - 41
SP - 1
EP - 12
PB - Elsevier Inc.
AN - OPUS4-65545
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shovo, Redoy Gazi
A1 - Thünemann, Andreas
A1 - Katcharava, Zviadi
A1 - Marinvo, Anja
A1 - Hoppe, Richard
A1 - Woltersdorf, Georg
A1 - Du, Mengxue
A1 - Androsch, Rene
A1 - de Souza e Silva, Juliana Martins
A1 - Busse, Karste
A1 - Binder, Wolfgang H.
T1 - Generating Tagged Micro- and Nanoparticles of Poly(ethylene furanoate) and Poly(ethylene terephthalate) as Reference Materials
N2 - Detecting nanoplastic particles in environmental samples and biological tissues remains a significant challenge, especially in view of newly emerging polymers, not yet commercially exploited. Fluorescent labeling provides a tagging strategy to overcome this limitation by reducing the detection limit of individual particles, especially for small-sized particles. We present a method for producing labeled nanoparticles (NP/MP) of poly(ethylene terephthalate) (PET) and poly(ethylene furanoate) (PEF), tagged with Alexa Fluor 633 or Alexa Fluor 647. Our preparations used mechanical grinding or solvent-based approaches (confined impinging jet mixing, ((CIJ, precipitation), generating particles with hydrodynamic diameters of 200–700 nm, displaying long-term stability in water of up to 57 days. Stable suspensions with concentrations of the particles ranging from 10 µg/mL (surfactant-free, by solvent mixing) to 5.88 mg/mL (precipitation, containing surfactant) were generated with zeta-potentials from −5 to −50 mV. Characterization of the nanoparticles by SEC, DSC, and XRD showed no significant changes in molecular weight, thermal behavior, or crystallinity via the solvent-based methods, compared to the pristine polymer, highlighting their suitability for producing standardized nanoparticle dispersions. Fluorescence spectroscopy of the Alexa-dye-labeled particles confirmed the successful incorporation of the Alexa dyes, so improving monitoring of their biological profiles of the PEF-MP/NPs. s-SNOM (near field imaging) could identify individual PEF-particles sized ∼200 nm by direct imaging.
KW - Reference Materials
KW - Nanoplastics
KW - Microplastics
KW - Polymer
KW - Fluorescence
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655531
DO - https://doi.org/10.1002/marc.202500839
SN - 1521-3927
VL - 47
IS - 4
SP - 1
EP - 11
PB - Wiley VHC-Verlag
CY - Weinheim
AN - OPUS4-65553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prakash, Swayam
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Rapid Onsite Detection of Fecal Contamination in Water Using a Portable Fluorometric Assay
N2 - Fecal pollution in water poses significant health risks, especially when contaminated sources are used for drinking and food production. Traditional water quality testing methods are expensive, slow, and require skilled personnel, limiting their accessibility. This work addresses these issues by developing a portable fluorometric assay for the detection of the fecal indicator pigment urobilin (UB). The assay uses silane-functionalized glass fiber strips impregnated with zinc chloride, providing a ‘drop-&-detect’ approach with enhanced fluorescence response mediated by the unique complexation properties of ZnCl2 and UB. This approach allows for the detection of UB at sub-nanomolar concentrations in less than 1 min using a 3D-printed setup with miniaturized optical components powered by a smartphone with its camera as a detector. The results validated with a benchtop fluorometer show the effectiveness of this method. The successful application of this userfriendly, rapid, and sensitive assay to real water samples from three rivers and the influx and efflux of a wastewater treatment plant advances field-based water quality monitoring, meets the WHO’s ASSURED criteria, and supports progress toward the global clean water and sanitation goals.
KW - Fecal pigment
KW - Fluorescence
KW - Signal amplification
KW - Surface chemistry
KW - Water quality testing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655543
DO - https://doi.org/10.1021/acssensors.5c03922
SN - 2379-3694
VL - 11
SP - 1
EP - 9
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-65554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Engel, Philipp
A1 - Recknagel, Christoph
ED - Lienhart, Werner
T1 - SensoJointField - Umsetzung eines IoT-Netzwerkes für das Deformationsmonitoring hochbeanspruchter Betonfahrbahndecken
N2 - Fugen und deren dauerhafter abdichtender Verschluß sind sehr sensible Konstruktionselemente des Betonstraßenbaus. Um die Nutzungs- und Lebensdauer nachhaltig zu erhöhen, ist die Kenntnis der realen Beanspruchungen entscheidend. Um die Deformationsbeanspruchungen im Fugenbereich unter realen Nutzungsbedingungen aufzuklären, wurde durch die BAM ein innovatives Monitoringsystem "SensoJoint" entwickelt, welches Monitoringkampagnen autark im Feld realisieren kann. Konzeptionsansatz und die technische Realisierung dieses IoT-Sensornetzwerkes werden im Beitrag beschreiben.
T2 - Ingenieurvermessung 26
CY - Graz, Austria
DA - 10.02.2026
KW - Sensorik
KW - Infrastruktur
KW - Dauerhaftigkeit
KW - Performance
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655505
SN - 978-3-99161-070-0
DO - https://doi.org/10.3217/978-3-99161-070-0
VL - 1
SP - 184
EP - 193
PB - Verlag der Technischen Universität Graz
CY - Verlag der TU Graz, Technikerstraße 4, 8010 Graz
AN - OPUS4-65550
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pei, R.
A1 - Petrazoller, J.
A1 - Atila, Achraf
A1 - Arnoldi, S.
A1 - Xiao, L.
A1 - Liu, X.
A1 - Wang, H.
A1 - Korte-Kerzel, S.
A1 - Berbenni, S.
A1 - Richeton, T.
A1 - Guénolé, J.
A1 - Xie, Z.
A1 - Al-Samman, T.
T1 - Solute co-segregation mechanisms at low-angle grain boundaries in magnesium: A combined atomic-scale experimental and modeling study
N2 - Solute segregation at low-angle grain boundaries (LAGBs) critically affects the microstructure and mechanicalproperties of magnesium (Mg) alloys. In modern alloys containing multiple substitutional elements, understanding solute-solute interactions at microstructural defects becomes essential for alloy design. This study investigates the co-segregation mechanisms of calcium (Ca), zinc (Zn), and aluminum (Al) at a LAGB in a dilute Mg-0.23Al-1.00Zn-0.38Ca (AZX010) alloy by combining atomic-scale experimental and modeling techniques.Three-dimensional atom probe tomography (3D-APT) revealed significant segregation of Ca, Zn, and Al at the LAGB, with Ca forming linear segregation patterns along dislocation arrays characteristic of the LAGB. Clustering analysis showed increased Ca–Ca pairs at the boundary, indicating synergistic solute interactions.
Atomistic simulations and elastic dipole calculations demonstrated that larger Ca atoms prefer tensile regions around dislocations, while smaller Zn and Al atoms favor compressive areas. These simulations also found that Ca–Ca co-segregation near dislocation cores is energetically more favorable than other solute pairings, explaining the enhanced Ca clustering observed experimentally. Thermodynamic modeling incorporating calculated segregation energies and solute-solute interactions accurately predicted solute concentrations at the LAGB, aligning with experimental data. The findings emphasize the importance of solute interactionsat dislocation cores in Mg alloys, offering insights for improving mechanical performance through targeted alloying and grain boundary engineering.
KW - Atomic probe tomography
KW - Atomistic simulation
KW - Grain boundary
KW - Co-segregation
KW - Magnesium alloy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655248
DO - https://doi.org/10.1016/j.actamat.2026.121947
SN - 1359-6454
VL - 306
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-65524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Redda, Zinnabu Tassew
A1 - Prinz, Carsten
A1 - Yimam, Abubeker
A1 - Barz, Mirko
A1 - Becker, Katharina
A1 - Gizaw, Desta Getachew
A1 - Laß-Seyoum, Asnakech
T1 - Structural and textural characterization of Brassica carinata biochar to investigate its potential industrial applications
N2 - Biochar, a low-cost, and carbon-rich product of the thermal decomposition of biomass under oxygen-limited conditions and at relatively low temperatures, has recently been identified as a promising porous material with a wide range of industrial applications. In the present study, a comprehensive analysis of proximate, ultimate, nutrient profile, structural, and textural properties of a biochar derived from two Ethiopian indigenous Brassica carinata cultivars was conducted. The characterization of the biochar was achieved by employing a variety of well-established methods, including proximate analysis (moisture, volatile matter, ash content, and fixed carbon), ultimate analysis (C, S, and O content), atomic oxygen to carbon ratio (O/C), morphological and elemental composition analysis through scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDS). Furthermore, a combination of mercury intrusion porosimetry (MIP), dynamic vapor sorption (DVS), and gas adsorption methods such as nitrogen and krypton gas adsorption, were used for an in-depth study of the porous structure. SEM morphological characterization showed that the biochar surfaces showed multiple pores of diverse sizes and shapes. EDS elemental composition analysis revealed that sodium, aluminium, and silicon were not detected, but potassium, calcium, magnesium, and iron were all present in noticeable amounts. Furthermore, ultimate analysis showed that the most prevalent elements were carbon (86 wt.%) and oxygen (10.41‒9.77 wt.%), while sulphur was present in negligible concentrations. MIP analysis demonstrated that the porosities of the biochars varied from 62.68 to 69.99 wt.%, with the Holetta-1 biochar showing the highest porosity. The superior porosity of Holetta-1, as confirmed via MIP analysis, yielded higher values for bulk volume (2.36 mL g− 1), skeletal volume (1.65 mL g− 1), and total intrusion volume (1.65 mL g− 1) compared to the Yellow Dodolla. The most frequent pore diameters were 172.46 μm for Yellow Dodolla and 111.42 μm for Holetta-1. The MIP log differential pore diameter distributions were observed to vary from 18 to 411 μm and 10 to 411 μm, respectively, for Yellow Dodolla and Holetta-1. Despite the biochars’ low specific surface areas (0.17–0.21 m² g⁻¹), krypton sorption was a suitable technique for its characterization compared to DVS and nitrogen sorption methods. In conclusion, the characterization studies confirmed that this carbon-rich porous material possesses unique and valuable properties, with these attributes position it as a promising alternative for diverse industrial applications, contributing to the development of a bio-based circular economy.
KW - Morphological characterization
KW - Mercury intrusion porosimetry
KW - Gas adsorption
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655325
DO - https://doi.org/10.1038/s41598-025-32063-1
SN - 2045-2322
VL - 16
IS - 1
SP - 1
EP - 19
PB - Springer Science and Business Media LLC
AN - OPUS4-65532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lisec, Jan
A1 - Recknagel, Sebastian
A1 - Prinz, Carsten
A1 - Vogel, Kristin
A1 - Koch, Matthias
A1 - Becker, Roland
T1 - eCerto—versatile software for interlaboratory data evaluation and documentation during reference material production
N2 - The statistical tool eCerto was developed for the evaluation of measurement data to assign property values and associated uncertainties of reference materials. The analysis is based on collaborative studies of expert laboratories and was implemented using the R software environment. Emphasis was put on comparability of eCerto with SoftCRM, a statistical tool based on the certification strategy of the former Community Bureau of Reference. Additionally, special attention was directed towards easy usability from data collection through processing, archiving, and reporting. While the effects of outlier removal can be flexibly explored, eCerto always retains the original data set and any manipulation such as outlier removal is (graphically and tabularly) documented adequately in the report. As a major reference materials producer, the Bundesanstalt für Materialforschung und -prüfung (BAM) developed and will maintain a tool to meet the needs of modern data processing, documentation requirements, and emerging fields of RM activity. The main features of eCerto are discussed using previously certified reference materials.
KW - Reference material
KW - Statistics
KW - Software
KW - Collaborative trial
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591851
DO - https://doi.org/10.1007/s00216-023-05099-3
SP - 1
EP - 9
PB - Springer Science and Business Media LLC
AN - OPUS4-59185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bugel, S.
A1 - Hahnel, M.
A1 - Kunde, T.
A1 - de Sousa Amadeu, Nader
A1 - Sun, Y.
A1 - Spieß, A.
A1 - Beglau, T. H. Y.
A1 - Janiak, C.
A1 - Schmidt, B. M.
T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation
N2 - A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,4′-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,2′,3,3′,5,5′,6,6′-octafluoro-4,4′-biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM.
KW - MOF
KW - Filter
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547632
DO - https://doi.org/10.3390/ma15082807
SN - 1996-1944
VL - 15
IS - 8
SP - 1
EP - 18
PB - MDPI
AN - OPUS4-54763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Prinz, Carsten
A1 - Hase, Felix
A1 - Kruschwitz, Sabine
T1 - Data of embedded humidity sensors, sample weights, and measured pore volume distribution for eight screed types
N2 - Four cement-based and four calcium-sulphate-based screed types are investigated. The samples have a diameter of 300 mm and a height of 35 or 70 mm. Up to ten humidity sensors are embedded directly during the concreting of the screed samples. Thus, the humidity over the sample height is monitored during hardening, hydration, evaporation, and oven drying. Furthermore, the screed samples are weighed during every measurement to determine the total mass and the corresponding moisture loss.
To define the pore system precisely, mercury intrusion porosimetry as well as gas adsorption is performed. According to the data, the entire pore volume distribution is known. The measured pore diameters range from 0.8 nm to 100 µm and the total porosity of the examined screeds ranges between 11% and 22%.
Based on these measurement data, moisture transport, pore saturation as well as sorption isotherms and their hysteresis may be calculated quantitatively as described in “Monitoring of the absolute water content in porous materials based on embedded humidity sensors” (Strangfeld and Kruschwitz, 1921).
KW - Concrete and screed
KW - Embedded humidity sensors
KW - Pore volume distribution
KW - Material moisture
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-462339
DO - https://doi.org/10.1016/j.dib.2018.09.020
SN - 2352-3409
VL - 21
SP - 8
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-46233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Kun
A1 - Schukar, Marcus
A1 - Hicke, Konstantin
A1 - Lu, Xin
T1 - Effect of humidity on fiber-optic temperature sensing
N2 - This study investigates the influence of ambient humidity on the temperature sensitivity, measurement accuracy, and uncertainty of optical fibers with different coatings, using a Rayleigh-based distributed sensing technique. Polymer-coated fibers (acrylate and polyimide) and metal-coated fibers (copper and gold) were tested under controlled humidity (30%–90% RH) and temperature (20–60 °C) conditions. Rayleigh-based measurements revealed a slight but consistent decrease in temperature sensitivity with increasing humidity for all polymer-coated fibers, attributed to humidity-induced changes in coating stiffness and strain transfer. In contrast, metal-coated fibers exhibited humidity-independent behavior and superior stability. These findings highlight the non-negligible role of ambient humidity in fiber-optic temperature sensing, particularly in Rayleigh-based systems using hygroscopic coatings. The results provide practical guidance for fiber and coating selection in humid environments and offer broader insight into humidity–strain–temperature coupling mechanisms relevant to other fiber-optic sensing mechanisms.
KW - Distributed sensing
KW - Humidity effect
KW - Temperature sensing
KW - Optical fiber coatings
KW - Temperature uncertainty
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650040
DO - https://doi.org/10.1016/j.measurement.2025.119905
SN - 0263-2241
VL - 261
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-65004
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gerrits, Ruben
A1 - Stepec, Biwen An
A1 - Bäßler, Ralph
A1 - Becker, Roland
A1 - Dimper, Matthias
A1 - Feldmann, Ines
A1 - Goff, Kira L.
A1 - Günster, Jens
A1 - Hofmann, Andrea
A1 - Hesse, René
A1 - Kirstein, Sarah
A1 - Klein, Ulrich
A1 - Mauch, Tatjana
A1 - Neumann-Schaal, Meina
A1 - Özcan Sandikcioglu, Özlem
A1 - Taylor, Nicole M.
A1 - Schumacher, Julia
A1 - Shen, Yin
A1 - Strehlau, Heike
A1 - Weise, Matthias
A1 - Wolf, Jacqueline
A1 - Yurkov, Andrey
A1 - Gieg, Lisa M.
A1 - Gorbushina, Anna
T1 - A 30-year-old diesel tank: Fungal-dominated biofilms cause local corrosion of galvanised steel
N2 - The increased use of biodiesel is expected to lead to more microbial corrosion, fouling and fuel degradation issues. In this context, we have analysed the metal, fuel and microbiology of a fouled diesel tank which had been in service for over 30 years. The fuel itself, a B7 biodiesel blend, was not degraded, and—although no free water phase was visible—contained a water content of ~60 ppm. The microbial community was dominated by the fungus Amorphotheca resinae, which formed thick, patchy biofilms on the tank bottom and walls. The tank sheets, composed of galvanised carbon steel, were locally corroded underneath the biofilms, up to a depth of a third of the sheet thickness. On the biofilm-free surfaces, Zn coatings could still be observed. Taken together, A. resinae was shown to thrive in these water-poor conditions, likely enhancing corrosion through the removal of the protective Zn coatings.
KW - Fungal biofilms
KW - Biodiesel degradation mechanisms
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655014
DO - https://doi.org/10.1038/s41529-025-00731-2
SN - 2397-2106
VL - 10
IS - 1
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65501
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodricks, Carol Winnifred
A1 - Prockat, Annabell
A1 - Kalinka, Gerhard
A1 - Trappe, Volker
T1 - Novel Recyclable Hierarchical Carbon Fiber/Epoxy Composites: Preserving Fiber Length and Orientation Using Elium
N2 - Current recycling methods for polymer matrix composites produce short, unoriented carbon fibers, limiting their use to intermediate‐strength applications. A method is therefore needed to recycle fibers while preserving their original length and orientation, enabling a circular economy for carbon fiber composites. This study proposes a novel hierarchical composite designed to retain fiber length and orientation during recycling. Virgin carbon fibers are encased in an insoluble epoxy matrix to form tapes that act as the primary units of the structure. The primary tape matrix shields the fibers from chemical degradation while preserving their alignment throughout recycling. The tapes are then embedded in a secondary recyclable matrix, Elium, a thermoplastic polymer soluble in acetone with mechanical properties comparable to epoxy. The composite is recycled by dissolving the secondary Elium matrix in acetone and recovering the primary tape units with intact fiber length and orientation. The primary units can then be used to assemble new composites. In this study, hierarchical composite laminates underwent recycling up to three times. Their mechanical properties were assessed after each cycle. Laminates with an Elium secondary matrix retained 60%–90% of the mechanical performance of epoxy‐based laminates. Minimal degradation was observed between cycles, and fiber length, orientation, and volume fraction were fully preserved. Pushout tests confirmed that fibers in the primary tapes were sufficiently shielded during the recycling process. These results validate the feasibility of a hierarchical recyclable composite that combines recyclability with high mechanical performance, serving as a proof of concept and providing opportunities for future development.
KW - Review
KW - Interface
KW - Micromechanics
KW - Polymer matrix composites
KW - Glass fibre reinforced composites
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655276
DO - https://doi.org/10.1002/pc.70869
SN - 0272-8397
SP - 1
EP - 16
PB - Wiley Periodicals LLC.
AN - OPUS4-65527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästle, Emanuel D.
A1 - Duffner, Eric
A1 - Popiela, Bartosz
A1 - Ghaznavi, Ali
T1 - Monitoring Failure of Composite Pressure Vessels with Acoustic Emissions
N2 - Two carbon fiber reinforced type IV pressure vessels are subjected to step-wise pressurization until burst, while monitored using acoustic emissions (AE). Unlike most prior studies, AE data is collected throughout the entire damage progression. The vessels, manufactured with differing parameters, failed in distinct composite layers – A-type in the hoop layers and B-type in the helical layers. The AE signals are evaluated to study material degradation and identify fiber breaks as signs of critical damage accumulation. The signals are distributed randomly across the surface, with localized accumulation only minutes before rupture, close to the rupture plane. The difference in manufacturing parameters did not result in any clear difference in the AE activity. Felicity and Shelby ratios show consistent decline with increasing pressure, suggesting potential for damage assessment and burst prediction. It is discussed how these ratios are affected by coupling quality of the AE sensors, the shape of the pressurization profile and prior loadings. Different signal features based on the amplitude and the frequency content are extracted for a classification into failure mechanisms. Based on previous studies, AE signals corresponding to fiber breaks have a characteristic high-frequency spectrum and show a delay in occurrence, with an increase in the number of breaking fibers towards the end of the experiment. Indeed, high frequency signals tend to occur later and signals in specific peak-frequency ranges (350 – 400 kHz, 500 kHz) somewhat resemble the expected behavior. However, the dataset is too variable and too incongruent for any clear interpretations. Likely reasons are signal propagation effects, the complex composite structure, simultaneous occurrence of signals and measurement uncertainties. A review of relevant studies is provided to show that similar issues affect also previous works. Successfully identifying fiber breaks in large-scale, complex composite structures based on AE data, and turning this into an applicable health-monitoring technique, therefore remains a challenge.
KW - Acoustic emission testing
KW - Composite pressure vessels
KW - Damage classification in fiber reinforced polymers
KW - Felicity ratio
KW - Composite failure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654852
DO - https://doi.org/10.1007/s10921-025-01319-1
SN - 0195-9298
VL - 45
IS - 1
SP - 1
EP - 19
PB - Springer Science and Business Media LLC
AN - OPUS4-65485
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dixneit, J.
A1 - Gibmeier, J.
A1 - Kromm, Arne
A1 - Schubnell, J.
A1 - Lang, F.
A1 - Loebich, F.
A1 - Carl, E.-R.
A1 - Ya, W.
T1 - Residual stress distribution of a large component manufactured by AM-DED-Arc from high-strength weld filler material X90
N2 - Currently, DED-Arc manufactured components are not covered by design guidelines, and design factors such as residual stress factors are not defined for such components. This hinders industrial use, especially for components with a remaining surface waviness required by industry. For the first time the stress state of a high-strength, low-alloy, large-scale DED-Arc component was characterised in the as-built state and after cutting off the component from the substrate plate. Complementary methods of residual stress analyses were applied to gain a holistic insight into the residual stress distributions of a thick-walled part. In the as-built state, direction-dependent and position-dependent tensile residual stresses were found for the component at the level of the yield strength of the part. The additive manufacturing strategy continuous spiral deposition has no significant influence on the residual stresses in bead threshold area compared to the residual stresses of the remaining component. For this case, bead threshold is no structural imperfection. By removing the part from the substrate plate, the residual stresses are significantly redistributed. Tensile residual stresses are then present at a moderate level. Compressive residual stresses were determined in the volume of the deposited material. The general consideration of ‘‘high’’ tensile residual stresses in such thick-walled components is rather conservative. Therefore, design guidelines should take the manufacturing condition into account.
KW - AM-DED-Arc
KW - Residual stress
KW - High strength steel
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655239
DO - https://doi.org/10.1177/03093247251406876
SN - 2041-3130
SP - 1
EP - 18
PB - SAGE
AN - OPUS4-65523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Reischel, Mercedes
A1 - Krankenhagen, Rainer
A1 - Myrach, Philipp
A1 - Steinfurth, Henrik
A1 - Röllig, Mathias
T1 - Anwendungsbereiche und Grenzen der Blitzthermografie - Entwicklung eines anwendungsnahen Standards
N2 - Ein anwendungsnaher Standard zur aktiven Thermografie mit Blitzanregung soll die Auswahl und Bewertung der geeigneten Messtechnik, die Durchführung der Messungen sowie die Auswertung und Darstellung der Messdaten in Abhängigkeit vom Prüfproblem festlegen. In diesem Beitrag werden zum einen Möglichkeiten zur Charakterisierung der Blitzlichtanregung sowie alternative Anregungstechniken vorgestellt. Zum anderen wurden für verschiedene Prüfprobleme Referenzprobekörper entwickelt, die systematische Untersuchungen zur Optimierung der Messparameter ermöglichten.
T2 - DACH Jahrestagung 2012
CY - Graz, Österreich
DA - 17.09.2012
PY - 2012
AN - OPUS4-32798
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Koyutürk, B.
A1 - Farber, E.
A1 - Wagner, F.
A1 - Fellinger, Tim-Patrick
A1 - Eisenberg, D.
T1 - A simple decagram-scale synthesis of an atomically dispersed, hierarchically porous Fe–N–C catalyst for acidic ORR
N2 - Carbons doped with iron and nitrogen (Fe–N–Cs) are highly promising electrocatalysts for energy conversion reactions in the oxygen, nitrogen and carbon cycles. Containing no platinum group metals, they nevertheless compete with platinum-based catalysts in crucial fuel cell reactions, such as oxygen reduction in acid. Yet deployment of Fe–N–Cs in fuel cells requires also a flow-enhancing pore structure, and a scalable synthesis procedure – a rarely-met combination of requirements. We now report such a simple synthesis of over 10 g of an Fe–N–C catalyst with high activity towards oxygen reduction in acid. Atomically-dispersed Fe–N4 active sites were designed orthogonally and simultaneously with hierarchical micro-, meso- and macroporosity, by exploiting a dual role of magnesium ions during pyrolysis. Combining the “active site imprinting” and “self-templating” strategies in a single novel magnesium iminodiacetate precursor yielded a catalyst with high specific surface area (SSA > 1600 m2 g−1), a flow-enhancing hierarchical porosity, and high relative abundance of the most desirable D1-type Fe–N4 sites (43%, by Mössbauer spectroscopy at 4.2 K). Despite the relatively low iron contents, the catalysts feature halfwave potentials up to 0.70 V vs. RHE at pH 1 and a mass activity of 1.22 A g−1 at 0.8 V vs. RHE in RDE experiments. Thanks to the simple and scalable synthesis, this active and stable catalyst may serve as a workhorse in academic and industrial research into atomically-dispersed ORR electrocatalysis.
KW - Catalysis
KW - Fe-N-C catalysts
KW - Fuel Cells
KW - Electrochemistry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550113
DO - https://doi.org/10.1039/d2ta00925k
SN - 2050-7488
SP - 1
EP - 10
PB - Royal Society of Chemistry
AN - OPUS4-55011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Titirici, M.
A1 - Baird, S. G.
A1 - Sparks, T. D.
A1 - Yang, S. M.
A1 - Brandt-Talbot, A.
A1 - Hosseinaei, O.
A1 - Harper, D. P.
A1 - Parker, R. M.
A1 - Vignolini, S.
A1 - Berglund, L. A.
A1 - Li, Y.
A1 - Gao, H.-L.
A1 - Mao, L.-B.
A1 - Yu, S.-H.
A1 - Díez, N.
A1 - Ferrero, G. A.
A1 - Sevilla, M.
A1 - Szilágyi, P. Á.
A1 - Stubbs, C. J.
A1 - Worch, J. C.
A1 - Huang, Y.
A1 - Luscombe, C. K.
A1 - Lee, K.-Y.
A1 - Luo, H.
A1 - Platts, M. J.
A1 - Tiwari, D.
A1 - Kovalevskiy, D.
A1 - Fermin, D. J.
A1 - Au, H.
A1 - Alptekin, H.
A1 - Crespo-Ribadeneyra, M.
A1 - Ting, V. P.
A1 - Fellinger, Tim-Patrick
A1 - Barrio, J.
A1 - Westhead, O.
A1 - Roy, C.
A1 - Stephens, I. E. L.
A1 - Nicolae, S. A.
A1 - Sarma, S. C.
A1 - Oates, R. P.
A1 - Wang, C.-G.
A1 - Li, Z.
A1 - Loh, X. J.
A1 - Myers, R. J.
A1 - Heeren, N.
A1 - Grégoire, A.
A1 - Périssé, C.
A1 - Zhao, X.
A1 - Vodovotz, Y.
A1 - Earley, B.
A1 - Finnveden, G.
A1 - Björklund, A.
A1 - Harper, G. D. J.
A1 - Walton, A.
A1 - Anderson, P. A.
T1 - The sustainable materials roadmap
N2 - Our ability to produce and transform engineered materials over the past 150 years is responsible for our high standards of living today, especially in the developed economies. Yet, we must carefully think of the effects our addiction to creating and using materials at this fast rate will have on the future generations. The way we currently make and use materials detrimentally affects the planet Earth, creating many severe environmental problems. It affects the next generations by putting in danger the future of economy, energy, and climate. We are at the point where something must drastically change, and it must change NOW. We must create more sustainable materials alternatives using natural raw materials and inspiration from Nature while making sure not to deplete important resources, i.e. in competition with the food chain supply. We must use less materials, eliminate the use of toxic materials and create a circular materials economy where reuse and recycle are priorities. We must develop sustainable methods for materials recycling and encourage design for disassembly. We must look across the whole materials life cycle from raw resources till end of life and apply thorough life cycle assessments based on reliable and relevant data to quantify sustainability.
KW - Electrochemistry
KW - Fe-N-C catalysts
KW - Fuel cells
KW - Catalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550126
DO - https://doi.org/10.1088/2515-7639/ac4ee5
SN - 2515-7639
VL - 5
IS - 3
SP - 1
EP - 98
PB - IOP Publishing
CY - Bristol
AN - OPUS4-55012
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, Davide
A1 - Li, Yan‐Sheng
A1 - Damjanović, Ana Marija
A1 - Proux, Olivier
A1 - Wagner, Friedrich E.
A1 - Fellinger, Tim-Patrick
A1 - Gasteiger, Hubert A.
A1 - Piana, Michele
T1 - On the Stability of an Atomically‐Dispersed Fe−N−C ORR Catalyst: An In Situ XAS Study in a PEMFC
N2 - The stability of Fe−N−C oxygen reduction reaction (ORR) electrocatalysts has been considered a primary challenge for their practical application in proton exchange membrane fuel cells (PEMFCs). While several studies have attempted to reveal the possible degradation mechanism of Fe−N−C ORR catalysts, there are few research results reporting on their stability as well as the possible Fe species formed under different voltages in real PEMFC operation. In this work, we employ in‐situ X‐ray absorption near‐edge structure (XANES) to monitor the active‐site degradation byproducts of an atomically dispersed Fe−N−C ORR catalyst under a H2/O2‐operating PEMFC at 90 % relative humidity and 80 °C. For this, stability tests were carried out at two constant cell voltages, namely 0.4 and at 0.8 V. Even though the ORR activity of the Fe−N−C catalyst decreased significantly and was almost identical at the end of the tests for the two voltages employed, the analysis of the XANES recorded under H2/N2 configuration at 0.6 and 0.9 V within the stability test suggests that two different degradation mechanisms occur. They are demetalation of iron cations followed by their precipitation into Fe oxides upon operation at 0.8 V, versus a chemical carbon oxidation close to the active sites, likely triggered by reactive oxygen species (ROS) originated from the H2O2 formation, during the operation at 0.4 V.
KW - PGM-free catalysts
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638981
DO - https://doi.org/10.1002/celc.202400228
SN - 2196-0216
VL - 11
IS - 18
SP - 1
EP - 16
PB - Wiley VHC-Verlag
AN - OPUS4-63898
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rappsilber, Tim
A1 - Yusfi, Nawar
A1 - Krüger, Simone
A1 - Hahn, S.-K.
A1 - Fellinger, Tim-Patrick
A1 - Krug von Nidda, Jonas
A1 - Tschirschwitz, Rico
T1 - Meta-analysis of heat release and smoke gas emission during thermal runaway of lithium-ion batteries
N2 - Herein a meta-analysis of 76 experimental research papers from 2000 to 2021 is given about possible effects on the thermal runaway of lithium-ion battery cells. Data on the hazards of gas emissions and released heat are related to each other and differentiated by cell properties such as, cell geometry, cathode type or state of charge. Quantitative information on the total heat release in the range of 2.0–112.0 kJ Wh−1, the peak heat release rate in the range of 0.006–2.8 kW Wh−1and the smoke gas emission were extracted, normalized in terms of cell energy (Wh), combined in a data library and compared graphically. The total amount of gas emitted (3–48 mmol Wh−1) as well as the released amount of carbon monoxide (1–161 mg Wh−1) and hydrogen fluoride (2–197 mg Wh−1) were investigated as a function of the state of charge and cell geometry. The analysis reveals that the measured values are significantly influenced by the types of calorimeters and smoke gas analyzers used as well as by the type of thermal runaway trigger. This meta-analysis can serve as an important basis for any risk assessment of lithium-ion batteries.
KW - Lithium-ion battery
KW - Thermal runaway
KW - Cathode active material
KW - Heat release
KW - Smoke gas emission
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568071
DO - https://doi.org/10.1016/j.est.2022.106579
SN - 2352-152X
VL - 60
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Low, Jian Liang
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Paulus, B.
A1 - Fellinger, Tim-Patrick
T1 - The Tetrapyrollic Motif in Nitrogen Doped Carbons and M-N-C Electrocatalysts as Active Site in the Outer-Sphere Mechanism of the Alkaline Oxygen Reduction Reaction
N2 - Development and fundamental understanding of precious-group-metal-free electrocatalysts is hampered by limitations in the quantification of the intrinsic activity of different catalytic sites and understanding the different reaction mechanisms. Comparing isomorphic nitrogen-doped carbons, Zn-N-Cs and Fe-N-Cs with the common tetrapyrrolic motif, a catalyst-independent outer-sphere rate-determining step in the alkaline oxygen reduction reaction is observed. Density functional theory (DFT) simulations on tetrapyrrolic model structures indicate the highest occupied molecular orbital (HOMO) level as a good descriptor for the catalytic activity. Contour plots suggest that the electron transfer occurs directly from the tetrapyrrolic coordination site, rather than from the metal center. Metal-free tetrapyrrolic N4 sites are discovered to be highly active oxygen reduction reaction (ORR) active sites in alkaline that reach turnover frequencies (TOF) of 0.33 and 1.84 s−1 at 0.80 and 0.75 VRHE in the order of magnitude of tetrapyrrolic Fe–N4 sites in the acidic ORR. While Zn-coordination lowers the HOMO level and therefore the catalytic activity, Fe-coordination lifts the HOMO level resulting in TOF values of 0.4 and 4 s−1 for tetrapyrrolic Fe–N4 sites at 0.90 and 0.85 VRHE, respectively. At higher mass activities, the peroxide reduction becomes rate-limiting, where highest peroxide production rates are observed for the nitrogen-doped carbon.
KW - Tetrapyrollic
KW - Motif
KW - Nitrogen
KW - Carbons
KW - Alkaline Oxygen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606239
DO - https://doi.org/https://doi.org/10.1002/aenm.202400482
SN - 1614-6832
VL - 2024
SP - 1
EP - 8
PB - Wiley-VCH
AN - OPUS4-60623
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, I.
A1 - Rieck, Arielle
A1 - Mehmood, Asad
A1 - Bublitz, R.
A1 - Bongers, L.
A1 - Weuster-Botz, D.
A1 - Fellinger, Tim-Patrick
T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons
N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of −2.4 to −3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however required. Atomically-dispersed M−N−C catalysts show promise, if degradation throughout autoclaving can be omitted. The development of selective and autoclavable catalysts resistant to contamination and electrode design for the complex electrolyte will enable efficient bioelectrocatalytic power-to-X systems based on the introduced BES.
KW - Energy Conversion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594766
DO - https://doi.org/10.1002/celc.202300344
SN - 2196-0216
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, I.
A1 - Rieck, Arielle
A1 - Mehmood, Asad
A1 - Bublitz, R.
A1 - Bongers, L.
A1 - Weuster-Botz, D.
A1 - Fellinger, Tim-Patrick
T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons
N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of 2.4 to 3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however requ
KW - PEM
KW - Stirred-Tank Bioreactor
KW - Clostridium ragsdalei
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615239
UR - http://www.chemelectrochem.org/
DO - https://doi.org/10.1002/celc.202300344
VL - 11
IS - 6
SP - 1
EP - 9
PB - Chemistry Europe and Wiley-VCH GmbH
AN - OPUS4-61523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wagner, F.
A1 - Fellinger, Tim-Patrick
T1 - Evaluation of the Specific Activity of MNCs and the Intrinsic Activity of Tetrapyrrolic FeN4 Sites for the Oxygen Reduction Reaction
N2 - M−N−C electrocatalysts are considered pivotal to replace expensive precious group metal-based materials in electrocatalytic conversions. However, their development is hampered by the limited availability of methods for the evaluation of the intrinsic activity of different active sites, like pyrrolic FeN4 sites within Fe−N−Cs. Currently, new synthetic procedures based on active-site imprinting followed by an ion exchange reaction, e.g. Zn-to-Fe, are producing single-site M−N−Cs with outstanding activity. Based on the same replacement principle, we employed a conservative iron extraction to partially remove the Fe ions from the N4 cavities in Fe−N−Cs. Having catalysts with the same morphological properties and Fe ligation that differ solely in Fe content allows for the facile determination of the decrease in density of active sites and their turn-over frequency. In this way, insight into the specific activity of M−N−Cs is obtained and for single-site catalysts the intrinsic activity of the site is accessible. This new approach surpasses limitations of methods that rely on probe molecules and, together with those techniques, offers a novel tool to unfold the complexity of Fe−N−C catalyst and M−N−Cs in general.
KW - Fe-N-C catalysts
KW - M-N-C catalysts
KW - Fuel Cells
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567406
DO - https://doi.org/10.1002/anie.202207089
SN - 1433-7851
VL - 61
IS - 50
SP - 1
EP - 6
PB - Wiley-VHC
AN - OPUS4-56740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Wagner, F. E.
A1 - Fellinger, Tim-Patrick
T1 - Life cycle of single atom catalysts: a Mo¨ssbauer study on degradation and reactivation of tetrapyrrolic Fe–N–C powders
N2 - The degradation of a single-site atomically dispersed, model Fe–N–C powder catalyst with high activity is investigated using cryo-Mössbauer spectroscopy. The results indicate a degradation initiated by an Fe2+ to Fe3+ oxidation due to coordination of oxygen to tetrapyrrolic Fe–N4 sites at atmospheric conditions (change between characteristic doublets) before iron(III) oxide is formed (sextet). Thermal reactivation can be used to restore substantial catalytic activity of aged Fe–N–C powders.
KW - Life cycle
KW - Atom catalysts
KW - Tetrapyrrolic Fe–N–C powders
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586007
DO - https://doi.org/10.1039/d3mh00308f
SN - 2051-6347
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - Wagner, F. E.
A1 - Fellinger, Tim-Patrick
T1 - Life cycle of single atom catalysts: a Mössbauer study on degradation and reactivation of tetrapyrrolic Fe–N–C powders
N2 - The degradation of a single-site atomically dispersed, model Fe–N–C powder catalyst with high activity is investigated using cryo-Mössbauer spectroscopy. The results indicate a degradation initiated by an Fe2+ to Fe3+ oxidation due to coordination of oxygen to tetrapyrrolic Fe–N4 sites at atmospheric conditions (change between characteristic doublets) before iron(III) oxide is formed (sextet). Thermal reactivation can be used to restore substantial catalytic activity of aged Fe–N–C powders.
KW - Single atom catalysts
KW - Mössbauer study
KW - Tetrapyrrolic Fe–N–C powders
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589352
DO - https://doi.org/10.1039/d3mh00308f
VL - 10
SP - 5577
EP - 5583
PB - Royal Society of Chemistry
AN - OPUS4-58935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Atila, Achraf
A1 - Bakhouch, Yasser
A1 - Xie, Zhuocheng
T1 - Revealing the void-size distribution of silica glass using persistent homology
N2 - Oxide glasses have proven to be useful across a wide range of technological applications. Nevertheless, their medium-range structure has remained elusive. Previous studies focused on ring statistics as a metric of the medium-range structure, but this metric provides an incomplete picture of the glassy structure. Here, we use atomistic simulations and state-of-the-art topological analysis tools, namely persistent homology (PH), to analyze the medium-range structure of the archetypal oxide glass (Silica) at ambient temperatures and with varying pressures. PH presents an unbiased definition of loops and voids, providing an advantage over other methods for studying the structure and topology of complex materials, such as glasses, across multiple length scales. We captured subtle topological transitions in medium-range order and cavity distributions, providing new insights into glass structure. Our work provides a robust way for extracting the void distribution of oxide glasses based on PH.
KW - Medium-range
KW - Voids
KW - Topology
KW - Silica glass
KW - Atomistic simulations
KW - Persistent homology
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655690
DO - https://doi.org/10.1016/j.mtla.2025.102613
VL - 44
SP - 1
EP - 11
PB - Elsevier Inc.
AN - OPUS4-65569
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shaikh, Abdul Shaafi
A1 - Fardan, Ahmed
A1 - Mishurova, Tatiana
A1 - Hryha, Eduard
T1 - The Impact of High‐Productivity Processing on the Fatigue Failure of an Additive Manufactured Superalloy HAYNES 282
N2 - The elevated temperature low cycle fatigue life of additively manufactured HAYNES 282 superalloy from conventional 40 µm layer thickness process parameters was compared with that of high‐productivity 80 µm layer thickness process parameters. Wrought 282 alloy was also tested in parallel for comparison. The 40 µm process parameters produced fatigue life between 1400 and 1700 cycles to failure, the 80 µm process parameter specimens failed after ≈1200 cycles, and the wrought alloy reached 1350 cycles to failure. Microstructure investigations did not reveal systematic differences in phase constituents or grain structure between 40 and 80 µm processed 282 alloy. While both process parameters produced porosity of less than 0.05% by volume, high‐resolution X‐ray computed tomography showed the occurrence of large aspect ratio lack of fusion defects in the 80 µm material. These defects were also identified on fracture surfaces and could be related to the accelerated initiation and propagation of cracks, especially when oriented perpendicular to the load axis in samples built parallel to the building direction. The results emphasize the criticality of seemingly minor variations in defect characteristics on performance in cyclic loading conditions for high strength alloys.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - PBF-LB
KW - Fatigue
KW - EBSD
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655732
DO - https://doi.org/10.1002/adem.202502048
SN - 1438-1656
SP - 1
EP - 13
PB - Wiley-VCH GmbH
AN - OPUS4-65573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tiwari, Jitendar Kumar
A1 - Malladi, Bala
A1 - Mishurova, Tatiana
A1 - Fritsch, Tobias
A1 - Nyborg, Lars
A1 - Cao, Yu
T1 - Influence of contour parameters on the surface roughness of fine channels produced by powder bed fusion-laser beam
N2 - Surface roughness strongly influences the performance of fine internal channels in additively manufactured components. This study investigates how contour process parameters affect the surface finish of 1 mm-diameter channels produced by powder bed fusion–laser beam (PBF-LB). Five contour parameter sets with progressively increasing laser energy density (LED) were applied, while keeping infill parameters constant. Surface roughness was evaluated using surface profilometry, X-ray computed tomography (XCT), and optical microscopy (OM). Profilometry and OM provided localized measurements, whereas XCT captured full-channel roughness along the build direction. Results show that increasing LED initially reduces surface roughness due to improved melting and removal of partially fused particles, reaching optimal smoothness at an intermediate LED. Further LED increase causes roughness to rise again, attributed to balling and dross formation. Optical cross-sections depicted these trends, and XCT measurements closely matched profilometry data. The findings in this study highlight a trade-off between surface quality and dimensional accuracy, as higher LEDs improve smoothness but reduce channel diameter. This work establishes an optimal contour LED range for minimizing as-built surface roughness in fine internal channels, which can enhance the functional performance of PBF-LB components in aerospace, medical, and energy applications.
KW - Additive manufacturing
KW - PBF-LB
KW - Surface roughness
KW - Computed tomography
KW - Optical tomography
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655677
DO - https://doi.org/10.1016/j.vacuum.2026.115085
SN - 0042-207X
VL - 246
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-65567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Semenova, Aleksandra
A1 - Spitzer Sra, Stefan H.
A1 - Dvorakova, Barbora
A1 - Askar, Enis
A1 - Funnemann, Patrick
A1 - Hermanns, Roy T.E.
A1 - Jankuj, Vojtech
A1 - Vignes, Alexis
A1 - Kuracina, Richard
A1 - Szabova, Zuzana
A1 - Norman, Frederik
A1 - Gabel, Dieter
A1 - Danzi, Enrico
A1 - Makarova, Ekaterina
A1 - Lorenzon, Ivan
A1 - Toman, Adrian
A1 - Adamus, Wojciech
A1 - Hessels, Conrad
T1 - Towards standardized safety protocols for iron-based energy carriers: International alignment through round robin testing on safety characteristics
N2 - Background Iron powder appears to be a promising solution for long-term energy storage and (inter-) continental transport, as it is safe to store and does not require energy to maintain its state, unlike, for instance, liquefied hydrogen. However, while the fundamental research is well underway, large-scale implementation is still in its early stages, with a growing number of promising demonstrators emerging. Methods This article contributes to the large-scale implementation of iron as an energy carrier by presenting a round-robin test of four iron powders currently used in research and larger-scale demonstrators. These powders were tested on their safety characteristics in the standard 20 L apparatus across eight European countries. Results The resulting data are intended to support future standardization efforts using different iron samples as standardized fuel. All tested powders were classified either as non-explosible or as belonging to the category of marginally explosible dusts (Class 1). This provides a clear picture of the level of explosion protection measures that need to be considered for the safe use of iron powders in energy carrier applications. Conclusions Along with that, the study detected variations in the results and pointed to shortcomings in the current standards that may cause such discrepancies. These findings emphasize the importance of improving testing procedures to support standardization and ensure the safe use of iron powder as an energy carrier using an a-priori-approach rather than subsequent testing.
KW - Explosion protection
KW - Energy carrier
KW - Safety characteristics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655761
DO - https://doi.org/10.12688/openreseurope.22839.1
SN - 2732-5121
VL - 6
SP - 1
EP - 20
PB - F1000 Research Ltd
AN - OPUS4-65576
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Eddah, Mustapha
A1 - Markötter, Henning
A1 - Mieller, Björn
A1 - Widjaja, Martinus Putra
A1 - Beckmann, Jörg
A1 - Bruno, Giovanni
T1 - Multi-Energy High Dynamic Range (HDR) Synchrotron X-ray Computed Tomography applied to LTCC samples
N2 - Synchrotron X-ray computed tomography (SXCT) is regularly used in materials science to correlate structural properties with macroscopic properties and to optimize manufacturing processes. The X-ray beam energy must be adapted to the sample properties, such as size and density. If both strongly and weakly absorbing materials are present, the contrast to the weakly absorbing materials is lost, resulting in image artifacts and a poor signal-to-noise ratio (SNR). One example is a low-temperature co-fired ceramics (LTCC), in which metal connections are embedded in a ceramic matrix and form 3-dimensional conducting structures. This article describes a method of combining SXCT scans acquired at different beam energies, significantly reducing metal artifacts, and improving image quality. We show how to solve the difficult task of merging the scans at low and high beam energy. Our proposed merging approach achieves up to 35% improvement in SNR within ceramic regions adjacent to metallic conductors. In this way, previously inaccessible regions within the ceramic structure close to the metallic conductors are made accessible. The paper further discusses methodological requirements, limitations, and potential extensions of the presented multienergy SXCT merging technique.
T2 - iCT 2026
CY - Linz, Austria
DA - 10.02.2026
KW - Synchrotron x-ray CT
KW - Multi-energy CT
KW - Low-Temperature cofired ceramics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655848
SP - 1
EP - 7
CY - e-Journal of Nondestructive Testing
AN - OPUS4-65584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachet, G.
A1 - Wei, S.
A1 - Tehranchi, Ali
A1 - Dong, X.
A1 - Lestang, J.
A1 - Zhang, A.
A1 - Sun, B.
A1 - Zaefferer, S.
A1 - Gault, B.
A1 - Ponge, D.
A1 - Raabe, D.
ED - Tehranchi, Ali
T1 - Protection of metal interfaces against hydrogen-assisted cracking
N2 - Enabling a hydrogen economy requires the development of materials resistant to hydrogen embrittlement (HE). More than 100 years of research have led to several mechanisms and models describing how hydrogen interacts with lattice defects and leads to mechanical property degradation. However, solutions to protect materials from hydrogen are still scarce. Here, we investigate the role of interstitial solutes in protecting critical crystalline defects sensitive to hydrogen. Ab initio calculations show that boron and carbon in solid solutions at grain boundaries can efficiently prevent hydrogen segregation. We then realized this interface protection concept on martensitic steel, a material strongly prone to HE, by doping the most sensitive interfaces with different concentrations of boron and carbon. These segregations, in addition to stress relaxations, critically reduce the hydrogen ingress by half, leading to an unprecedented resistance against HE. This tailored interstitial segregation strategy can be extended to other metallic materials susceptible to hydrogen-induced interfacial failure.
KW - Hydrogen embrittlement
KW - interstitial
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650881
DO - https://doi.org/10.1038/s41467-025-67310-6
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-65088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gaal, Mate
A1 - Wernicke, Pascal
T1 - Improved air-coupled ultrasonic transmission using pulse compression
N2 - Air-coupled ultrasonic testing avoids contamination and reduces maintenance costs, but suffers from poor signal-to-noise ratio (SNR) due to impedance mismatch. Rather than developing new transducers, this study improves SNR through signal processing by adapting pulse compression from radar.We propose a method using unipolar square pulses to make pulse compression compatible with non-linear transducers such as ferroelectrets and thermoacoustic emitters. Instead of relying on analytical models, a reference transmission measurement served as the matched filter, simplifying implementation and ensuring adaptability across transducer types. We evaluated unipolar coded excitation and pulse compression on ultrasonic transmission through a 25mm polyvinyl chloride plate, varying code length and pulse delay. Significant SNR gains were observed across transducers, particularly with longer delays. These results confirm that pulse compression enhances peak localization and supports testing under low-SNR conditions.
Further experiments showed that pulse compression remains effective despite side lobe overlap and noise, provided the pulse delay is chosen appropriately. Although SNR prediction is limited by electrical and acoustic interference, the method consistently improves detection. Overall, the results demonstrate the feasibility of unipolar excitation coding for pulse compression in air-coupled ultrasonic testing, with practical value for thick or attenuating materials.
KW - Air-coupled ultrasound
KW - Coded excitation
KW - Pulse compression
KW - Transducers
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655005
DO - https://doi.org/10.1109/OJUFFC.2026.3659047
SN - 2694-0884
VL - 6
SP - 9
EP - 16
PB - Institute of Electrical and Electronics Engineers (IEEE)
AN - OPUS4-65500
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gaal, Mate
A1 - Álvarez-Arenas, Tomás Gómez
T1 - Guest Editorial: Special Section on Air-Coupled Ultrasound
N2 - Air-coupled ultrasound is a challenging field dominated by the drastic impedance mismatch between air and all condensed matter, the low ultrasound velocity in the air, and the rapidly increasing attenuation with frequency.
The seven articles included in this special section showcase the diversity of current research on air-coupled ultrasound. All contributions in this special section are application-oriented, demonstrating the readiness of air-coupled ultrasound technologies to address real-world challenges. Whether it’s ensuring food safety, supporting heritage conservation, optimizing industrial inspection, or enabling in-field biological measurements, the practical relevance of these studies makes this section
particularly valuable for both researchers and industry professionals.
KW - Air-coupled ultrasound
KW - Transducers
KW - Non-destructive testing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655041
DO - https://doi.org/10.1109/OJUFFC.2026.3656857
SN - 2694-0884
VL - 6
SP - 1
EP - 2
PB - Institute of Electrical and Electronics Engineers (IEEE)
AN - OPUS4-65504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hajhariri, Aliasghar
A1 - Eberwein, Robert
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Cozzani, Valerio
A1 - Seidlitz, Holger
T1 - Cryogenic storage safety: Experimental evaluation of insulation under extreme conditions
N2 - Hydrogen is recognized as a keystone of the global energy transition, offering a clean, high-energy-density energy carrier ideal for storage and transportation. Among various storage options, liquid hydrogen (LH2) is especially advantageous for both mobile and stationary applications. However, ensuring the safety and performance of LH2 storage systems under extreme thermal conditions, such as fire exposure, remains an engineering challenge.
This study introduces an experimental framework, called the Cryogenic High-Temperature Thermal Vacuum Chamber (CHTTVC), designed to investigate the thermal-hydraulic response of vacuum-insulated cryogenic tanks under fire-like conditions. The apparatus enables evaluation of insulation performance, such as perlite and multilayer insulation (MLI), with a focus on thermal degradation, heat ingress, and vacuum stability.
Results indicate that combustible MLIs undergo substantial thermal degradation, leading to heat ingress rates of up to 6.5 kW and the formation of hazardous combustion by-products. In contrast, non-combustible MLIs and bulk insulation materials restrict heat ingress to approximately 3 kW while more effectively preserving vacuum integrity. Combustible MLIs also exhibit pronounced pressure increases in the evacuated section, reaching ∼6 × 104 Pa, nearly six times higher than those observed for non-combustible counterparts. Analysis of effective emissivity further reveals an enhancement in radiative heat transfer, approximately five times, for combustible MLIs following degradation. Additionally, marked thermal stratification develops under both nominal and extreme heat loads, with temperature gradients approaching 10 °C per 100 mm during sustained thermal exposure.
KW - Multi-Layer Insulation
KW - Cryogenic Storage
KW - Safety
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655380
DO - https://doi.org/10.1016/j.jlp.2026.105961
SN - 0950-4230
VL - 101
SP - 1
EP - 20
PB - Elsevier Ltd.
AN - OPUS4-65538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Helfenstein, J.
A1 - Massey, M.
A1 - Kretzschmar, R.
A1 - Schade, U.
A1 - Verel, R.
A1 - Chadwick, O.
A1 - Frossard, E.
T1 - Spectroscopic analysis shows crandallite can be a major component of soil phosphorus
N2 - Phosphorus (P) bioavailability is crucial for the productivity of natural and agricultural ecosystems, and soil P speciation plays a major role therein. Better understanding of P forms present in soil is thus essential to predict bioavailability. However, P speciation studies are only as powerful as the reference spectra used to interpret them, and most studies rely on a limited set of reference spectra. Most studies on soil P forms differentiate between Ca-bound P (e.g. apatite), organic P, Fe-bound P, and Al-bound P. In our analysis of a Ca, Al, and P rich soil from the Kohala region of Hawaii, we identified the mineral crandallite, CaAl3(PO4)2(OH)5·H2O, a mineral previously not considered to play a significant role in soils. Crandallite was first identified with powder X-ray diffraction. Subsequently reference spectra were collected, and the presence of crandallite was confirmed using micro-focused P K-edge X-ray absorption near edge structure (XANES) spectroscopy, micro-infrared spectroscopy, and solid-state 31P nuclear magnetic resonance (NMR) spectroscopy. Crandallite XANES spectra were distinct from other common XANES spectra due to the presence of features in the post-edge region of the spectrum. Linear combination fitting of bulk P K-edge XANES spectra allowed the determination of the proportion of crandallite to the total P content, indicating that crandallite comprises up to half, possibly even more of the soil P in the samples. Crandallite is therefore an important and potentially overlooked component of soil P, which pedogenically forms in soils with high P, Al, and Ca contents, where it could play an important role in P bioavailability.
KW - Phosphorus
KW - XANES spectrosocpy
KW - Infrared spectroscopy
KW - NMR spectrocopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654968
DO - https://doi.org/10.1016/j.geoderma.2026.117712
SN - 0016-7061
VL - 467
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65496
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Helfenstein, J.
A1 - Massey, M.
A1 - Sekine, R.
A1 - Kretzschmar, R.
A1 - Beiping, L.
A1 - Peter, T.
A1 - Chadwick, O.
A1 - Tamburini, F.
A1 - Rivard, C.
A1 - Herzel, Hannes
A1 - Adam, Christian
A1 - Pradas del Real, A.
A1 - Castillo-Michel, H.
A1 - Zuin, L.
A1 - Wang, D.
A1 - Félix, R.
A1 - Lassalle-Kaiser, B.
A1 - Frossard, E.
T1 - Microspectroscopy reveals dust-derived apatite grains in acidic, highly-weathered Hawaiian soils
N2 - Dust deposition is an important source of phosphorus (P) to many ecosystems. However, there is little evidence of dust-derived P-containing minerals in soils. Here we studied P forms along a well-described climatic Gradient on Hawaii, which is also a dust deposition gradient. Soil mineralogy and soil P forms from six sites along the climatic gradient were analyzed with bulk (X-ray diffraction and P K-edge X-ray absorption near edge structure) and microscale (X-ray fluorescence, P K-edge X-ray absorption near edge structure, and Raman) analysis methods. In the wettest soils, apatite grains ranging from 5 to 30 μm in size were co-located at the micro-scale with quartz, a known continental dust indicator suggesting recent atmospheric deposition. In addition to co-location with quartz, further evidence of dust-derived P included backward trajectory modeling indicating that dust particles could be brought to Hawaii from the major global dust-loading areas in central Asia and northern Africa. Although it is not certain whether the individual observed apatite grains were derived from long-distance transport of dust, or from local dust sources such as volcanic ash or windblown fertilizer, these observations offer direct evidence that P-containing minerals have reached surface layers of highly-weathered grassland soils through atmospheric deposition.
KW - Phosphorus
KW - soil
KW - microspectroscopy
KW - Raman spectroscopy
KW - XANES spectroscopy
KW - x-ray diffraction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511522
DO - https://doi.org/10.1016/j.geoderma.2020.114681
SN - 0166-0918
SN - 1872-6259
VL - 381
SP - 114681-1
EP - 114681-11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fortini, Renata
A1 - Meyer-Plath, A.
A1 - Kehren, D.
A1 - Gernert, U.
A1 - Agudo Jácome, Leonardo
A1 - Sturm, Heinz
T1 - Measurement of flexural rigidity of multi-walled carbon nanotubes by Dynamic Scanning Electron Microscopy
N2 - In this work the flexural rigidity of individual large diameter multi-walled carbon nanotubes (MWCNTs) was investigated. The bending modulus were obtained by detecting the resonance frequencies of mechanically excited cantilevered carbon nanotubes using the so-called dynamic scanning electron microscopy technique, and applying the Euler–Bernoulli beam theory. For the nanotubes studied, we determined a modulus of up to 160 GPa. This agrees with values reported by other authors for MWCNTs produced by catalytic chemical vapor deposition, however, it is 6-8 times smaller than values reported for single and multi-walled carbon nanotubes produced by arc-discharge synthesis. Toxicological studies with carbon nanotubes have been showing that inhaled airborne nanofibers that reach the deep airways of the respiratory system may lead to serious, asbestos-like lung diseases. These studies suggested that their toxicity critically depends on the fiber flexural rigidity, with high rigidity causing cell lesions. To complement the correlation between observed toxicological effects and fiber rigidities, reliable and routinely applicable measurement techniques for the flexural rigidity of nanofibers are required.
KW - Flexural rigidity
KW - Bending modulus
KW - Resonance frequency
KW - Carbon nanotubes
KW - Fiber toxicology
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514190
DO - https://doi.org/10.3390/fib8050031
SN - 2079-6439
VL - 8
IS - 5
SP - 31
PB - MDPI
AN - OPUS4-51419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smol, M.
A1 - Adam, Christian
A1 - Kugler, Stefan
T1 - Thermochemical Treatment of Sewage Sludge Ash (SSA)—Potential and Perspective in Poland
N2 - Phosphorus (P) recovery from sewage sludge ash (SSA) is one of the most promising approaches of phosphate rock substitution in mineral fertilizers and might be a sustainable way to secure supply of this raw material in the future. In the current investigation, the process of thermochemical treatment of SSA was applied to SSA coming from selected mono-incineration plants of municipal sewage sludge in Poland (Cracow, Gdansk, Gdynia, Lodz, Kielce and Szczecin).
The Polish SSA was thermochemically converted in the presence of sodium (Na) additives and a reducing agent (dried sewage sludge) to obtain secondary raw materials for the production of marketable P fertilizers. The process had a positive impact on the bioavailability of phosphorus and reduced the content of heavy metals in the obtained products. The P solubility in neutral Ammonium citrate, an indicator of its bioavailability, was significantly raised from 19.7–45.7% in the raw ashes and 76.5–100% in the thermochemically treated SSA. The content of nutrients in the recyclates was in the range of 15.7–19.2% P2O5, 10.8–14.2% CaO, 3.5–5.4% Na2O, 2.6–3.6% MgO and 0.9–1.3% K2O. The produced fertilizer raw materials meet the Polish norms for trace elements covered by the legislation: the content of lead was in the range 10.2–73.1 mg/kg, arsenic 4.8–22.7 mg/kg, Cadmium 0.9–2.8 mg/kg and mercury <0.05 mg/kg. Thus, these products could be potentially directly used for fertilizer production. This work also includes an analysis of the possibilities of using ashes for fertilizer purposes in Poland, based on the assumptions indicated in the adopted strategic and planning documents regarding waste management and fertilizer production.
KW - Sewage Sludge Ashes
KW - Critical raw materials
KW - Phosphorus
KW - Fertilizer
KW - Sewage Sludge
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514468
DO - https://doi.org/10.3390/en13205461
VL - 13
IS - 20
SP - 5461
AN - OPUS4-51446
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herzel, Hannes
A1 - Stemann, J.
A1 - Simon, Sebastian
A1 - Adam, Christian
T1 - Comparison of thermochemical treatment of sewage sludge ash with sodium sulphate in laboratory-scale and pilot-scale experiments
N2 - There is an ongoing debate on European scale concerning the criticality of phosphorus. In Switzerland and Germany, phosphorus recovery from phosphorus-rich waste streams will become obligatory. Sewage sludge ash is rich in phosphorus and may become an important secondary feedstock. Thermochemical treatment of sewage sludge ash with sodium sulphate under reducing conditions was shown to remove heavy metals from the solid product and produce the fully plant available crystalline phase CaNaPO4. Pilot-scale experiments in a rotary kiln were carried out at temperatures between 750 and 1000 °C and were compared to laboratory-scale experiments with crucibles. Process upscaling was successfully demonstrated but a series of differences were noticed: In comparison to laboratory-scale, solubility of phosphorus in samples from pilot-scale experiments was lower at all chosen treatment temperatures because of shorter retention time and incomplete decomposition of sodium sulphate. X-ray diffraction analysis revealed remaining phase fractions of whitlockite (Ca3-x(Mg,Fe)x(PO4)2) and sodium sulphate from the starting materials in products and thus indicated incomplete reaction. In contrast to the results of laboratory-scale experiments, the crystalline phase CaNaPO4 was clearly absent in the products from the rotary kiln but instead a Mg-bearing phase (Ca,Mg)NaPO4 was formed. Laboratory-scale experiments confirmed (Ca,Mg)NaPO4 is an intermediate phase between whitlockite and CaNaPO4. However, both crystalline phases are characterized by high plant availability. It was shown that heavy metal removal increased at higher temperatures whereas solubility and thus plant availability of phosphorus already reached its maxima at temperatures of 950 °C in pilot-scale and 875 °C in laboratory-scale experiments.
KW - Crystalline phase identification
KW - Heavy metal removal
KW - Phosphorus availability
KW - Process upscaling
KW - Recovery
KW - Rhenanite
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524084
DO - https://doi.org/10.1007/s13762-021-03252-y
VL - 19
IS - 3
SP - 1997
EP - 2006
PB - Springer
AN - OPUS4-52408
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weimann, Karin
A1 - Adam, Christian
A1 - Buchert, M.
A1 - Sutter, J.
T1 - Environmental Evaluation of Gypsum Plasterboard Recycling
N2 - Gypsum is widely used in the construction sector and its worldwide consumption has been increasing for several decades. Depending on the life-time of the used gypsum products, an increase of gypsum in construction and demolition waste follows. Especially against the background of a circular economy, the recycling of waste gypsum is of growing importance. However, the use of recycled gypsum makes only sense if it is environmentally friendly. Therefore, an evaluation of the environmental impacts of an industrial-scale processing for the recycling of post-consumer gypsum waste was conducted. The evaluation was performed with an established life cycle assessment software. Original data provided by industry and complementary data from a database for life cycle assessments were used for the calculations. Two scenarios for recycled gypsum with different transportation distances were calculated. These results are compared with results of the environmental evaluation of gypsum derived from coal-fired power plants (FGD gypsum) and natural gypsum. The results show that utilization of recycled gypsum can be environmentally advantageous compared to the use of natural gypsum or FGD gypsum, especially in the impact categories land transformation and resource consumption (abiotic depletion potential). For most environmental impact categories the specific transportation distances have a strong influence.
KW - Gypsum plasterboards
KW - Gypsum waste
KW - Recycled gypsum
KW - Environmental evaluation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522321
DO - https://doi.org/10.3390/min11020101
SN - 2075-163X
VL - 11
IS - 2
SP - 101
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-52232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cano Murillo, Natalia
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Hahn, Marc Benjamin
A1 - Hodoroaba, Vasile-Dan
A1 - Sturm, Heinz
T1 - Nanomechanical study of polycarbonate/boehmite nanoparticles/epoxy ternary composite and their interphases
N2 - Thermoplastic modified thermosets are of great interest especially due to their improved fracture toughness. Comparable enhancements have been achieved by adding different nanofillers including inorganic particles such as nanosized boehmite. Here, we present a nanomechanical study of two composite systems, the first comprising a polycarbonate (PC) layer in contact with epoxy resin (EP) and the second consisting of a PC layer containing boehmite nanoparticles (BNP) which is also in contact with an EP layer. The interaction between PC and EP monomer is tested by in situ Fourier transformed infrared (FT-IR) analysis, from which a reaction induced phase separation of the PC phase is inferred. Both systems are explored by atomic force microscopy (AFM) force spectroscopy. AFM force-distance curves (FDC) show no alteration of the mechanical properties of EP at the interface to PC. However, when a PC phase loaded with BNP is put in contact with an epoxy system during curing, a considerable mechanical improvement exceeding the rule of mixture was detected.
The trend of BNP to agglomerate preferentially around EP dominated regions and the stiffening effect of BNP on EP shown by spatial resolved measurements of Young's modulus, suggest the effective presence of BNP within the EP phase.
KW - Composites
KW - Mechanical properties
KW - Nanoparticles
KW - Thermoplastics
KW - Thermosets
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515965
DO - https://doi.org/10.1002/app.50231
SN - 0021-8995
SN - 1097-4628
VL - 138
IS - 12
SP - 1
EP - 11
PB - Wiley
CY - New York, NY
AN - OPUS4-51596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna Christiane
A1 - Pauw, Brian Richard
A1 - Sturm, Heinz
A1 - Günster, Jens
T1 - First time additively manufactured advanced ceramics by using two-photon polymerization for powder processing
N2 - Methods and materials are presented here, which enable the manufacturing of fine structures using a 3D-printing method known as two-photon polymerization (2PP). As traditional photolithography methods for structuring ceramic slurries do not function with 2PP, due to light scattering on ceramic particles, a novel water-based photoresist with high ceramic loading of extremely well dispersed ceramic nano particles was developed. This photoresist is basically a ceramic slurry containing a photocurable agent and a photoinitiator to be crosslinkable with the 780 nm wavelength femtosecond laser light source of the 2PP machine. It is demonstrated that it is possible to gain a highly transparent and low viscous slurry suitable for 2PP processing. This work shows the development of the slurry, first printing results and the post-printing processes required to form three dimensional ceramic microstructures consisting of alumina toughened zirconia (ATZ).
KW - 3D-printing
KW - Two-photon polymerization
KW - 2PP
KW - Ceramic nano particles
KW - Slurry
KW - Alumina toughened zirconia
KW - ATZ
KW - Additive manufacturing
KW - SchwarzP cells
KW - Nano-ceramic-additive-manufacturing photoresin
KW - NanoCAM
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517441
DO - https://doi.org/10.1016/j.oceram.2020.100040
VL - 4
SP - 100040
PB - Elsevier Ltd.
AN - OPUS4-51744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Christian
A1 - Hoffmann, Marie
A1 - Krüger, O.
A1 - Murzin, V.
A1 - Caliebe, W.
A1 - Adam, Christian
T1 - Chromium (VI) in phosphorus fertilizers determined with the diffusive gradients in thin-films (DGT) technique
N2 - Phosphorus (P) fertilizers from secondary resources became increasingly important in the last years. However, these novel P-fertilizers can also contain toxic pollutants such as chromium in its hexavalent state (Cr(VI)). This hazardous form of chromium is therefore regulated with low limit values for agricultural products even though the correct determination of Cr(VI) in these fertilizers may be hampered by redox processes, leading to false results. Thus, we applied the novel diffusive gradients in thin-films (DGT) technique for Cr(VI) in fertilizers and compared the results with the standard wet chemical extraction method (German norm DIN EN 15192) and Cr K-edge X-ray Absorption near-edge structure (XANES) spectroscopy. We determined an overall good correlation between the wet chemical extraction and the DGT method. DGT was very sensitive and for most tested materials selective for the analysis of Cr(VI) in P-fertilizers. However, hardly soluble Cr(VI) compounds cannot be detected with the DGT method since only mobile Cr(VI) is analyzed. Furthermore, Cr K-edge XANES spectroscopy showed that the DGT binding layer also adsorbs small amounts of mobile Cr(III) so that Cr(VI) values are overestimated. Since certain types of the P fertilizers contain mobile Cr(III) or partly immobile Cr(VI), it is necessary to optimize the DGT binding layers to avoid aforementioned over- or underestimation. Furthermore, our investigations showed that the Cr K-edge XANES spectroscopy technique is unsuitable to determine small amounts of Cr(VI) in fertilizers (below approx. 1% of Cr(VI) in relation to total Cr).
KW - Phosphorus fertilizer
KW - Sewage sludge ash
KW - Diffusive Gradients in thin films (DGT)
KW - Chemical extraction
KW - XANES spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509578
DO - https://doi.org/10.1007/s11356-020-08761-w
SN - 0944-1344
VL - 27
SP - 24320
EP - 24328
PB - Springer
AN - OPUS4-50957
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cunliffe, A. J.
A1 - Askew, P. D.
A1 - Stephan, Ina
A1 - Iredale, G.
A1 - Cosemans, P.
A1 - Simmons, L. M.
A1 - Verran, J.
A1 - Redfern, J.
T1 - How do we determine the efficacy of an antibacterial surface? A review of standardised antibacterial material testing methods
N2 - Materials that confer antimicrobial activity, be that by innate property, leaching of biocides or design features (e.g., non-adhesive materials) continue to gain popularity to combat the increasing and varied threats from microorganisms, e.g., replacing inert surfaces in hospitals with copper. To understand how efficacious these materials are at controlling microorganisms, data is usually collected via a standardised test method. However, standardised test methods vary, and often the characteristics and methodological choices can make it difficult to infer that any perceived antimicrobial activity demonstrated in the laboratory can be confidently assumed to an end-use setting. This review provides a critical analysis of standardised methodology used in academia and industry, and demonstrates how many key methodological choices (e.g., temperature, humidity/moisture, airflow, surface topography) may impact efficacy assessment, highlighting the need to carefully consider intended antimicrobial end-use of any product.
KW - Antimicrobial materials
KW - Antimicrobial testing
KW - ISO 22196
KW - Antimicrobial surfaces
KW - Antibacterial coatings
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532138
DO - https://doi.org/10.3390/antibiotics10091069
SN - 2079-6382
VL - 10
IS - 9
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-53213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herzel, Hannes
A1 - Aydin, Zeynep
A1 - Adam, Christian
T1 - Crystalline phase analysis and phosphorus availability after thermochemical treatment of sewage sludge ash with sodium and potassium sulfates for fertilizer production
N2 - Phosphorus rich sewage sludge ash is a promising source to produce phosphorus recycling fertilizer. However, the low plant availability of phosphorus in these ashes makes a treatment necessary. A thermochemical treatment (800–1000 °C) with alkali additives transforms poorly plant available phosphorus phases to highly plant available calcium alkali Phosphates (Ca,Mg)(Na,K)PO4. In this study, we investigate the use of K2SO4 as additive to produce a phosphorus potassium fertilizer in laboratory-scale experiments (crucible). Pure K2SO4 is not suitable as high reaction temperatures are required due to the high melting point of K2SO4.
To overcome this barrier, we carried out series of experiments with mixtures of K2SO4 and Na2SO4 resulting in a lower economically feasible reaction temperature (900–1000 °C). In this way, the produced phosphorus potassium fertilizers (8.4 wt.% K, 7.6 wt.% P) was highly plant available for phosphorus indicated by complete extractable phosphorus in neutral ammonium citrate solution. The added potassium is, in contrast to sodium, preferably incorporated into silicates instead of phosphorus phases. Thus, the highly extractable phase (Ca,Mg)(Na,K)PO4 in the thermochemical products contain less potassium than expected. This preferred incorporation is confirmed by a pilot-scale trial (rotary kiln) and thermodynamic calculation.
KW - Phosphorus recovery
KW - Recycling fertilizer
KW - Calcium alkali phosphate
KW - Silicate
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536276
DO - https://doi.org/10.1007/s10163-021-01288-3
SN - 1611-8227
IS - 23
SP - 2242
EP - 2254
PB - Springer
AN - OPUS4-53627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cano Murillo, Natalia
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Emamverdi, Farnaz
A1 - Cacua, K.
A1 - Hodoroaba, Vasile-Dan
A1 - Sturm, Heinz
T1 - Carrier Fibers for the Safe Dosage of Nanoparticles in Nanocomposites: Nanomechanical and Thermomechanical Study on Polycarbonate/Boehmite Electrospun Fibers Embedded in Epoxy Resin
N2 - The reinforcing effect of boehmite nanoparticles (BNP) in epoxy resins for fiber composite lightweight construction is related to the formation of a soft but bound interphase between filler and polymer. The interphase is able to dissipate crack propagation energy and consequently increases the fracture toughness of the epoxy resin. Usually, the nanoparticles are dispersed in the resin and then mixed with the hardener to form an applicable mixture to impregnate the fibers. If one wishes to locally increase the fracture toughness at particularly stressed positions of the fiber-reinforced polymer composites (FRPC), this could be done by spraying nanoparticles from a suspension. However, this would entail high costs for removing the nanoparticles from the ambient air. We propose that a fiber fleece containing bound nanoparticles be inserted at exposed locations. For the present proof-of-concept study, an electrospun polycarbonate nonwoven and taurine modified BNP are proposed. After fabrication of suitable PC/EP/BNP composites, the thermomechanical properties were tested by dynamic mechanical analysis (DMA). Comparatively, the local nanomechanical properties such as stiffness and elastic modulus were determined by atomic force microscopy (AFM). An additional investigation of the distribution of the nanoparticles in the epoxy matrix, which is a prerequisite for an effective nanocomposite, is carried out by scanning electron microscopy in transmission mode (TSEM). From the results it can be concluded that the concept of carrier fibers for nanoparticles is viable.
KW - Advanced materials
KW - Electrospun nanocomposite fiber
KW - Nanomechanical charecteisation
KW - Nanosafety
KW - Epoxy nanocomposites
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528265
DO - https://doi.org/10.3390/nano11061591
VL - 11
IS - 6
SP - 1591
PB - MDPI
CY - CH - 4020 Basel, Switzerland
AN - OPUS4-52826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raniro, H.R.
A1 - Soares, T.de M.
A1 - Adam, Christian
A1 - Pavinato, P.S.
T1 - Waste-derived fertilizers can increase phosphorus uptake by sugarcane and availability in a tropical soil
N2 - The use of highly water-soluble phosphorus (P) fertilizers can lead to P fixation in the soil, reducing fertilization efficiency. Waste-derived, low water-solubility sources can potentially increase sugarcane’s P uptake compared to triple superphosphate by reducing adsorption to the soil.
Aims:We aimed to test struvite, hazenite, and AshDec® for their agronomic potential as recycled fertilizers for sugarcane production in a typical tropical soil.We hypothesize that these sources can reduce P fixation in the soil, increasing its availability and sugarcane’s absorption.
Methods: In a greenhouse pot experiment, two consecutive sugarcane cycles, 90 days each, were conducted in a Ferralsol. The recovered sources struvite, hazenite, AshDec®, and the conventional triple superphosphate were mixed in the soil in three P doses (30, 60, and 90 mg kg–1), aside a control (nil-P). At both harvests, sugarcane number of sprouts, plant height, stem diameter, dry mass yield, shoot phosphorus, and soil P fractionation were investigated.
Results: At 90 days, struvite and hazenite performed better for dry mass yield (70.7 and 68.3 g pot–1, respectively) than AshDec® and triple superphosphate (59.8 and 57.4 g pot–1, respectively) and for shoot P, with 98.1, 91.6, 75.6, and 66.3 mg pot–1, respectively. At 180 days, struvite outperformed all treatments for dry mass yield (95.3 g pot–1) and AshDec® (75.5 mg pot–1) for shoot P. Struvite was 38% and hazenite 21% more efficient than triple superphosphate in P uptake, while AshDec® was 6% less efficient. Soil had higher labile P under struvite, hazenite, and AshDec® than triple superphosphate by the end of the first cycle, while only the later increased nonlabile P by the end of the experiment (180 days).
Conclusions:Waste-derived P sources were more efficient in supplying P for sugarcane and delivering labile P in 180 days than triple superphosphate.
KW - AshDec
KW - Hazenite
KW - P-efficiency
KW - Recycled sources
KW - Struvite
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544216
DO - https://doi.org/10.1002/jpln.202100410
SN - 1436-8730
SP - 1
EP - 12
PB - Wiley-VCH GmbH
AN - OPUS4-54421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schraut, Katharina
A1 - Kargl, F.
A1 - Adam, Christian
A1 - Ivashko, O.
T1 - In situ synchrotron XRD measurements during solidification of a melt in the CaO–SiO2 system using an aerodynamic levitation system
N2 - Phase formation and evolution was investigated in the CaO–SiO2 system in the range of 70–80 mol% CaO. The samples were container-less processed in an aerodynamic levitation system and crystallization was followed in situ by synchrotron x-ray diffraction at the beamline P21.1 at the German electron synchrotron (DESY). Modification changes of di- and tricalcium silicate were observed and occurred at lower temperatures than under equilibrium conditions. Despite deep sample undercooling, no metastable phase formation was observed within the measurement timescale of 1 s. For the given cooling rates ranging from 300 K s−1 to about 1 K s−1, no decomposition of tricalcium silicate was observed. No differences in phase evolution were observed between reducing and oxidizing conditions imposed by the levitation gas (Ar and Ar + O2). We demonstrate that this setup has great potential to follow crystallization in refractory oxide liquids in situ. For sub-second primary phase formation faster detection and for polymorph detection adjustments in resolution have to be implemented.
KW - Aerodynamic levitation
KW - Calcium silicate
KW - Phase formation
KW - Oxide melts
KW - In situ synchrotron x-ray diffraction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526952
DO - https://doi.org/10.1088/1361-648X/abf7e1
VL - 33
IS - 26
SP - 264003 (12pp)
PB - IOP Publishing
AN - OPUS4-52695
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Usmani, S.
A1 - Voss, L.
A1 - Stephan, Ina
A1 - Hübert, Thomas
A1 - Kemnitz, E.
T1 - Improved Durability of Wood Treated with Nano Metal Fluorides against Brown-Rot and White-Rot Fungi
N2 - Low-water soluble metal fluorides such as magnesium fluoride (MgF2) and calcium Fluoride (CaF2) were evaluated for decay protection of wood. Initially, the biocidal efficacy of nano metal fluorides (NMFs) against wood destroying fungi was assessed with an in-vitro agar test. The results from the test showed that agar medium containing MgF2 and CaF2 was more efficient in preventing fungal decay than stand-alone MgF2 or CaF2. These metal fluorides, in their nanoscopic form synthesized using fluorolytic sol-gel synthesis, were introduced into the sapwood of Scots pine and beech wood and then subjected to accelerated ageing by leaching (EN 84). MAS 19F NMR and X-ray micro CT images showed that metal fluorides were present in treated wood, unleached and leached. Decay resistance of Scots pine and beech wood treated with NMFs was tested against Wood destroying fungi Rhodonia placenta and Trametes versicolor in accordance with EN 113. Results revealed that mass losses were reduced to below 3% in wood treated with the combination of MgF2 and CaF2.
It is concluded that NMFs provide full protection to wood even after it has been leached and can be used as wood preservatives in outdoor environments.
KW - Nanoparticles
KW - Fluoride
KW - Wood protection
KW - Fluorolytic sol-gel synthesis
KW - Brown-rot fungi
KW - White-rot fungi
KW - Basidiomycetes
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543877
DO - https://doi.org/10.3390/app12031727
VL - 12
IS - 3
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-54387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, Sven
A1 - Topolniak, Ievgeniia
A1 - Weise, Matthias
A1 - Sturm, Heinz
T1 - Shape deviations of DLW microstructures in dependency of fabrication parameters
N2 - Deep understanding of the effects associated with fabrication parameters and their influence on the resulting structures shape is essential for the further development of direct laser writing (DLW). In particular, it is critical for development of reference materials, where structure parameters are precisely fabricated and should be reproduced with use of DLW technology. In this study we investigated the effect of various fabrication and preparation parameters on the structural precision of interest for reference materials. A well-studied photo-curable system, SZ2080 negative photo-resist with 1 wt.% Michler's ketone (Bis) photo-initiator, was investigated in this work. The correlation between applied laser power, laser velocity, fabrication direction on the deviations in the structure shape were observed by means of white light interferometry microscopy. Moreover, influence of slicing and hatching distances as well as prebake time were studied as function of sample shape. Deviations in the structure form between the theoretically expected and the one detected after DLW fabrication were observed in the range up to 15%. The observed shape discrepancies show the essential importance of fine-tuning the fabrication parameter for reference structure production.
KW - Direct laser writing
KW - Fabrication parameters
KW - Structural precision
KW - SZ2080 negative photo-resist
KW - White light interferometry microscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535906
DO - https://doi.org/10.1088/1361-6439/ac2a14
VL - 31
IS - 12
SP - 1
EP - 8
PB - IOP Science
AN - OPUS4-53590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sichler, Theresa Constanze
A1 - Adam, Christian
A1 - Barjenbruch, M.
A1 - Montag, D.
A1 - Mauch, Tatjana
A1 - Sommerfeld, Thomas
A1 - Ehm, J.H.
T1 - Variation of the element composition of municipal sewage sludges in the context of new regulations on phosphorus recovery in Germany
N2 - Phosphorus (P) recovery is obligatory for all sewage sludges with more than 20 g P/kg dry matter (DM) from 2029 in Germany. Nine wastewater treatment plants (WWTPs) were chosen to investigate variations of phosphorus contents and other parameters in sewage sludge over the year. Monthly sewage sludge samples from each WWTP were analyzed for phosphorus and other matrix elements (C, N, H, Ca, Fe, Al, etc.), for several trace elements (As, Cr, Mo, Ni, Pb, Sn) and loss of ignition. Among the nine WWTPs, there are four which have phosphorus contents both above and below the recovery limit of 20 g/kg DM along the year. Considering the average phosphorus content over the year, only one of them is below the limit. Compared to other matrix elements and parameters, phosphorus fuctuations are low with an average of 7% over all nine WWTPs. In total, only hydrogen and carbon are more constant in the sludge.
In several WWTPs with chemical phosphorus elimination, phosphorus fuctuations showed similar courses like iron and/or aluminum. WWTPs with chamber flter presses rather showed dilution efects of calcium dosage. As result of this study, monthly phosphorus measurement is highly recommended to determine whether a WWTP is below the
20 g/kg DM limit.
KW - Sewage sludge
KW - Phosphorus recovery
KW - Wastewater
KW - Phosphorus elimination
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557499
DO - https://doi.org/10.1186/s12302-022-00658-4
SN - 2190-4707
VL - 34
IS - 1
SP - 1
EP - 12
PB - Springer Nature
CY - Berlin
AN - OPUS4-55749
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sichler, Theresa Constanze
A1 - Adam, Christian
A1 - Becker, Roland
A1 - Sauer, Andreas
A1 - Ostermann, Markus
A1 - Barjenbruch, M.
T1 - Phosphorus determination in sewage sludge: comparison of different aqua regia digestion methods and ICP-OES, ICP-MS and photometric determination
N2 - Phosphorus recycling from sewage sludge will be obligatory in Germany from 2029. Phosphorus content determination in sewage sludge is crucial to assess the prescribed recycling rates. Currently, German law regards sample preparation using aqua regia digestion in a microwave or under reflux conditions as well as instrumental phosphorus determination by ICP-OES, ICP-MS, or photometric determination with ammonium molybdate as equivalent. However, it is questionable whether these methods are indeed equivalent regarding phosphorus quantification in sludges near the limit of 20 g/kg for mandatory recycling. To answer this question, 15 sewage sludges of 11 different wastewater treatment plants were investigated with all permitted method (digestion and measurement) combinations. Moreover, one sewage sludge was also examined in an interlaboratory comparison (ILC) with 28 participants. This study shows that the above-mentioned methods differ in some cases significantly but across all method combinations and sludges, phosphorus recovery was between 80 and 121% after normalization to the grand mean (average of 15 sludges between 85 and 111%). The ILC and the examination of 15 sludges produced largely similar results. There is a tendency to higher phosphorus recovery after microwave digestion compared to reflux digestion and ICP-OES measurements determine higher phosphorus contents than ICP-MS and photometric phosphorus determination. As a result, the authors recommend ICP-OES determination of phosphorus in sewage sludge after microwave digestion.
KW - Sewage sludge
KW - ICP-OES
KW - Phosphous recovery
KW - ICP-MS
KW - Photometric P determination
KW - Interlaboratory comparison
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558869
DO - https://doi.org/10.1186/s12302-022-00677-1
VL - 34
IS - 99
SP - 1
EP - 14
PB - Springer
AN - OPUS4-55886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dombinov, V.
A1 - Herzel, Hannes
A1 - Meiller, M.
A1 - Müller, F.
A1 - Willbold, S.
A1 - Zang, J. W.
A1 - da Fonseca-Zang, W. A.
A1 - Adam, Christian
A1 - Klose, H.
A1 - Poorter, H.
A1 - Jablonowski, N. D.
A1 - Schrey, S. D.
T1 - Sugarcane bagasse ash as fertilizer for soybeans: Effects of added residues on ash composition, mineralogy, phosphorus extractability and plant availability
N2 - Sugarcane bagasse is commonly combusted to generate energy. Unfortunately, recycling strategies rarely consider the resulting ash as a potential fertilizer. To evaluate this recycling strategy for a sustainable circular economy, we characterized bagasse ash as a fertilizer and measured the effects of co-gasification and co-combustion of bagasse with either chicken manure or sewage sludge: on the phosphorus (P) mass fraction, P-extractability, and mineral P phases. Furthermore, we investigated the ashes as fertilizer for soybeans under greenhouse conditions. All methods in combination are reliable indicators helping to assess and predict P availability from ashes to soybeans. The fertilizer efficiency of pure bagasse ash increased with the ash amount supplied to the substrate. Nevertheless, it was not as effective as fertilization with triple-superphosphate and K2SO4, which we attributed to lower P availability. Co-gasification and co-combustion increased the P mass fraction in all bagasse-based ashes, but its extractability and availability to soybeans increased only when co-processed with chicken manure, because it enabled the formation of readily available Ca-alkali phosphates. Therefore, we recommend co-combusting biomass with alkali-rich residues to increase the availability of P from the ash to plants.
KW - Combustion and gasification
KW - Phosphate extractability and availability
KW - X-ray diffraction (XRD)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567632
DO - https://doi.org/10.3389/fpls.2022.1041924
SN - 1664-462X
VL - 13
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-56763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lackmann, C.
A1 - Velki, M.
A1 - Šimić, A.
A1 - Müller, Axel
A1 - Braun, U.
A1 - Ečimović, S.
A1 - Hollert, H.
T1 - Two types of microplastics (polystyrene-HBCD and car tire abrasion) affect oxidative stress-related biomarkers in earthworm Eisenia andrei in a time-dependent manner
N2 - Microplastics are small plastic fragments that are widely distributed in marine and terrestrial environments. While the soil ecosystem represents a large reservoir for plastic, research so far has focused mainly on the impact on aquatic ecosystems and there is a lack of information on the potentially adverse effects of microplastics on soil biota. Earthworms are key organisms of the soil ecosystem and are due to their crucial role in soil quality and fertility a suitable and popular model organism in soil ecotoxicology.
Therefore, the aim of this study was to gain insight into the effects of environmentally relevant concentrations of microplastics on the earthworm Eisenia andrei on multiple levels of biological organization after different exposure periods. Earthworms were exposed to two types of microplastics: (1) polystyrene-HBCD and (2) car tire abrasion in natural soil for 2, 7, 14 and 28 d. Acute and chronic toxicity and all subcellular investigations were conducted for all exposure times, avoidance behavior assessed after 48 h and reproduction after 28 d. Subcellular endpoints included enzymatic biomarker responses, namely, carboxylesterase, glutathione peroxidase, acetylcholinesterase, glutathione reductase, glutathione S-transferase and catalase activities, as well as fluorescence-based measurements of oxidative stress-related markers and multixenobiotic resistance activity. Multiple biomarkers showed significant changes in activity, but a recovery of most enzymatic activities could be observed after 28 d. Overall, only minor effects could be observed on a subcellular level, showing that in this exposure scenario with environmentally relevant concentrations based on German pollution levels the threat to soil biota is minimal. However, in areas with higher concentrations of microplastics in the environment, these results can be interpreted as an early warning signal for more adverse effects. In conclusion, these findings provide new insights regarding the ecotoxicological effects of environmentally relevant concentrations of microplastics on soil organisms.
KW - Microplastics
KW - Earthworms
KW - Toxicity
KW - Biomarker
KW - oxidative stress
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545423
DO - https://doi.org/10.1016/j.envint.2022.107190
VL - 163
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-54542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Machado Ferreira de Araujo, F.
A1 - Duarte-Ruiz, D.
A1 - Saßnick, H.-D.
A1 - Gentzmann, Marie C.
A1 - Huthwelker, T.
A1 - Cocchi, C.
T1 - Electronic Structure and Core Spectroscopy of Scandium Fluoride Polymorphs
N2 - Microscopic knowledge of the structural, energetic, and electronic properties of scandium fluoride is still incomplete despite the relevance of this material as an intermediate for the manufacturing of Al−Sc alloys. In a work based on first-principles calculations and X-ray spectroscopy, we assess the stability and electronic structure of six computationally predicted ScF3 polymorphs, two of which correspond to experimentally resolved single-crystal phases. In the theoretical analysis based on density functional theory (DFT), we identify similarities among the polymorphs based on their formation energies, chargedensity distribution, and electronic properties (band gaps and density of states). We find striking analogies between the results obtained for the ow- and high-temperature phases of the material, indirectly confirming that the transition occurring between them mainly consists of a rigid rotation of the lattice. With this knowledge, we examine the X-ray absorption spectra from the Sc and F K-edge contrasting firstprinciples results obtained from the solution of the Bethe−Salpeter equation on top of all-electron DFT with high-energy-resolution fluorescence detection measurements. Analysis of the computational results sheds light on the electronic origin of the absorption maxima and provides information on the prominent excitonic effects that characterize all spectra. A comparison with measurements confirms that the sample is mainly composed of the high- and low-temperature polymorphs of ScF3. However, some fine details in the experimental results suggest that the probed powder sample may contain defects and/or residual traces of metastable polymorphs.
KW - Scandium
KW - X-ray spectroscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570727
DO - https://doi.org/10.1021/acs.inorgchem.2c04357
SN - 0020-1669
VL - 62
IS - 10
SP - 4238
EP - 4247
PB - ACS Publications
CY - Washington DC
AN - OPUS4-57072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
A1 - Plajer, A. J.
T1 - Thioanhydride/isothiocyanate/epoxide ring-opening terpolymerisation: sequence selective enchainment of monomer mixtures and switchable catalysis
N2 - We report a new sequence selective terpolymerisation in which three monomers (butylene oxide (BO) A, PhNCS B and phtalic thioanhydride (PTA) C) are selectively enchained into an (ABA′C)n sequence. PTA/PhNCS/BO ring-opening terpolymerisation ROTERP can be coupled with CS2 ROTERP to generate tetrapolymers and with εDL ROP in switchable catalysis for blockpolymer synthesis.
KW - Blockcopolymer
KW - 1H-NMR
KW - TGA
KW - DSC
KW - AFM
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552339
DO - https://doi.org/10.1039/d2py00629d
SP - 1
EP - 5
PB - Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-55233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Teixeira, M.M.
A1 - Moreno, L.F.
A1 - Stielow, B.J.
A1 - Muszewska, A.
A1 - Hainaut, M.
A1 - Gonzaga, L.
A1 - Abouelleil, A.
A1 - Patan, J.S.L.
A1 - Priest, M.
A1 - Souza, R.
A1 - Ferreira, K.S.
A1 - Zeng, Q.
A1 - da Cunha, M.M.L.
A1 - Gladki, A.
A1 - Barker, B.
A1 - Vicente, V.A.
A1 - de Souza, E.M.
A1 - Almeida, S.
A1 - Henrissat, B.
A1 - Vasconelos, A.T.R.
A1 - Deng, S.
A1 - Vogelmayr, H.
A1 - Moussa, T.A.A.
A1 - Gorbushina, Anna
A1 - Felipe, M.S.S.
A1 - Cuomo, C.A.
A1 - de Hoog, G.S.
T1 - Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota)
N2 - The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sexrelated genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi.
KW - Black yeast
KW - Comparative genomics
KW - Chaetothyriales
KW - Ecology
KW - Evolution
KW - Herpotrichiellaceae
KW - Phylogeny
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-408720
DO - https://doi.org/10.1016/j.simyco.2017.01.001
SN - 1872-9797
VL - 86
IS - 1
SP - 1
EP - 28
PB - Elsevier
CY - Amsterdam
AN - OPUS4-40872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Schutter, Jan David
A1 - Wagner, R.
A1 - Dimper, Matthias
A1 - Lützenkirchen-Hecht, D.
A1 - Özcan Sandikcioglu, Özlem
T1 - Abundance of Fe(III) during cultivation affects the microbiologically influenced corrosion (MIC) behaviour of iron reducing bacteria Shewanella putrefaciens
N2 - The effect of the presence of Fe(III) during the cultivation on the electrochemical activity and corrosion behaviour of dissimilatory iron reducing bacteria Shewanella putrefaciens was studied by means of ex situ and in situ X-ray absorption near-edge spectroscopy (XANES). Stainless steel AISI 304 and thin iron films were studied as substrates. XANES analysis indicated an accelerated iron dissolution and growth of an oxide/hydroxide film for the culture grown with Fe(III) in comparison to the culture grown in absence of Fe(III). Electrochemical Analysis indicated that the biofilm resulted in acceleration of the general corrosion but provides protection against local corrosion.
KW - Stainless Steel
KW - XANES
KW - Iron
KW - Cyclic Voltammetry
KW - Microbiological Corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513788
DO - https://doi.org/10.1016/j.corsci.2020.108855
VL - 174
SP - 108855
PB - Elsevier Ltd.
AN - OPUS4-51378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Schütter, Jan David
A1 - Wagner, R.
A1 - Dimper, Matthias
A1 - Hodoroaba, Vasile-Dan
A1 - Lützenkirchen-Hecht, D.
A1 - Özcan Sandikcioglu, Özlem
T1 - Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part II: Effect on biofilm formation and microbially influenced corrosion processes
N2 - Biofilm formation and microbially influenced corrosion of the iron-reducing microorganism Shewanella putrefaciens were investigated on stainless steel surfaces preconditioned in the absence and presence of flavin molecules by means of XANES (X-ray absorption near-edge structure) analysis and electrochemical methods. The results indicate that biofilm formation was promoted on samples preconditioned in electrolytes containing minute amounts of flavins. On the basis of the XANES results, the corrosion processes are controlled by the iron-rich outer layer of the passive film. Biofilm formation resulted in a cathodic shift of the open circuit potential and a protective effect in terms of pitting corrosion. The samples preconditioned in the absence of flavins have shown delayed pitting and the samples preconditioned in the presence of flavins did not show any pitting in a window of −0.3- to +0.0-V overpotential in the bacterial medium. The results indicate that changes in the passive film chemistry induced by the presence of minute amounts of flavins during a mild anodic polarization can change the susceptibility of stainless steel surfaces to microbially influenced corrosion.
KW - Biofilms
KW - XANES
KW - Microbially influenced corrosion (MIC)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528130
DO - https://doi.org/10.1002/maco.202012192
VL - 72
IS - 6
SP - 983
EP - 994
PB - Wiley
AN - OPUS4-52813
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Noack-Schönmann, Steffi
A1 - Bus, T.
A1 - Banasiak, Ronald
A1 - Knabe, Nicole
A1 - Broughton, William J.
A1 - Dulk-Ras, H.D.
A1 - Hooykaas, P.J.J.
A1 - Gorbushina, Anna
T1 - Genetic transformation of Knufia petricola A95 - a model organism for biofilm-material interactions
N2 - We established a protoplast-based system to transfer DNA to Knufia petricola strain A95, a melanised rock-inhabiting microcolonial fungus that is also a component of a model sub-aerial biofilm (SAB) system. To test whether the desiccation resistant, highly melanised cell walls would hinder protoplast formation, we treated a melanin-minus mutant of A95 as well as the type-strain with a variety of cell-degrading enzymes. Of the different enzymes tested, lysing enzymes from Trichoderma harzianum were most effective in producing protoplasts. This mixture was equally effective on the melanin-minus mutant and the type-strain. Protoplasts produced using lysing enzymes were mixed with polyethyleneglycol (PEG) and plasmid pCB1004 which contains the hygromycin B (HmB) phosphotransferase (hph) gene under the control of the Aspergillus nidulans trpC. Integration and expression of hph into the A95 genome conferred hygromycin resistance upon the transformants. Two weeks after plating out on selective agar containing HmB, the protoplasts developed cell-walls and formed colonies. Transformation frequencies were in the range 36 to 87 transformants per 10 µg of vector DNA and 106 protoplasts. Stability of transformation was confirmed by sub-culturing the putative transformants on selective agar containing HmB as well as by PCR-detection of the hph gene in the colonies. The hph gene was stably integrated as shown by five subsequent passages with and without selection pressure.
KW - DNA transfer
KW - Fungal cell-walls
KW - Protoplasts
KW - Hygromycin resistance
KW - Black yeast
KW - Sub-aerial biofilms
KW - Stress-protective morphology
KW - Ancestor of opportunistic pathogens & lichens
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-320840
UR - http://www.amb-express.com/content/4/1/80
DO - https://doi.org/10.1186/s13568-014-0080-5
SN - 2191-0855
VL - 4
SP - 80, 1
EP - 6
PB - Springer
CY - Heidelberg
AN - OPUS4-32084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erdmann, Eileen A.
A1 - Brandhorst, Antonia K. M.
A1 - Gorbushina, Anna
A1 - Schumacher, Julia
T1 - The Tet‑on system for controllable gene expression in the rock‑inhabiting black fungus Knufia petricola
N2 - Knufia petricola is a black fungus that colonizes sun-exposed surfaces as extreme and oligotrophic environments. As ecologically important heterotrophs and biofilm-formers on human-made surfaces, black fungi form one of the most resistant groups of biodeteriorating organisms. Due to its moderate growth rate in axenic culture and available protocols for its transformation and CRISPR/Cas9-mediated genome editing, K. petricola is used for studying the morpho-physiological adaptations shared by extremophilic and extremotolerant black fungi. In this study, the bacteria-derived tetracycline (TET)-dependent promoter (Tet-on) system was implemented to enable controllable gene expression in K. petricola. The functionality i.e., the dose-dependent inducibility of TET-regulated constructs was investigated by using GFP fluorescence, pigment synthesis(melanin and carotenoids) and restored uracil prototrophy as reporters. The newly generated cloning vectors containing the Tet-on construct, and the validated sites in the K. petricola genome for color-selectable or neutral insertion of expression constructs complete the reverse genetics toolbox. One or multiple genes can be expressed on demand from different genomic loci or from a single construct by using 2A self-cleaving peptides, e.g., for localizing proteins and protein complexes in the K. petricola cell or for using K. petricola as host for the expression of heterologous genes.
KW - Microcolonial fungi
KW - Inducible promoter
KW - Bimolecular fluorescence complementation
KW - 2A peptide
KW - CRISPR/ Cas9-mediated genome editing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607672
DO - https://doi.org/10.1007/s00792-024-01354-2
VL - 28
IS - 38
SP - 1
EP - 13
PB - Springer Nature
AN - OPUS4-60767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wetzel, Annica
A1 - Morell, Daniel
A1 - von der Au, Marcus
A1 - Witt, Julia
A1 - Özcan Sandikcioglu, Özlem
T1 - Transpassive Behavior of Equimolar CrMnFeCoNi and CrCoNi Multi‐Principal Element Alloys in an Alkaline NaCl Electrolyte
N2 - AbstractWe investigated the corrosion properties and transpassive behavior of CrMnFeCoNi and CrCoNi multi‐principal element alloys (MPEAs) in a 0.1 M NaCl electrolyte at pH 12. By using SECM‐based tip substrate voltammetry (TSV) in combination with the chemical analysis of the electrolyte, we were able to differentiate between anodic metal dissolution and oxygen evolution in the transpassive range. Our investigations have shown that CrCoNi has a significantly higher corrosion resistance compared to CrMnFeCoNi. In the studied alkaline environment, a transpassive oxide film is formed on the surface of CrCoNi during secondary passivation. This transpassive oxide film appears to play a significant role in oxygen evolution, as the increase in TSV currents at the microelectrode coincides with the corresponding current density plateau of the voltametric current trace. The formation of the transpassive oxide film was not observed in previous studies conducted in acidic environments. Moreover, the alkaline electrolyte induced a positive hysteresis and mild pitting corrosion, in addition to intergranular corrosion, which was the sole corrosion process observed at acidic pH levels. These findings enhance the understanding of the processes governing the transpassivity of CrMnFeCoNi and CrCoNi MPEAs in alkaline environments and have potential implications for the development of application‐tailored corrosion‐resistant MPEAs.
KW - Multi-principal element alloys
KW - MPEA
KW - Corrosion
KW - Oxygen evolution reaction
KW - Transpassive region
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611594
DO - https://doi.org/10.1002/celc.202400346
SN - 2196-0216
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-61159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ginés-Palomares, J.-C.
A1 - Fateri, M.
A1 - Schubert, T.
A1 - de Peindray d’Ambelle, L.
A1 - Simon, Sebastian
A1 - Gluth, Gregor
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Material aspects of sintering of EAC-1A lunar regolith simulant
N2 - Future lunar exploration will be based on in-situ resource utilization (ISRU) techniques. The most abundant raw material on the Moon is lunar regolith, which, however, is very scarce on Earth, making the study of simulants a necessity. The objective of this study is to characterize and investigate the sintering behavior of EAC-1A lunar regolith simulant. The characterization of the simulant included the determination of the phase assemblage, characteristic temperatures determination and water content analysis. The results are discussed in the context of sintering experiments of EAC-1A simulant, which showed that the material can be sintered to a relative density close to 90%, but only within a very narrow range of temperatures (20–30 °C). Sintering experiments were performed for sieved and unsieved, as well as for dried and non-dried specimens of EAC-1A. In addition, an analysis of the densification and mechanical properties of the sintered specimens was done. The sintering experiments at different temperatures showed that the finest fraction of sieved simulant can reach a higher maximum sintering temperature, and consequently a higher densification and biaxial strength. The non-dried powder exhibited higher densification and biaxial strength after sintering compared to the dried specimen. This difference was explained with a higher green density of the non-dried powder during pressing, rather than due to an actual influence on the sintering mechanism. Nevertheless, drying the powder prior to sintering is important to avoid the overestimation of the strength of specimens to be fabricated on the Moon.
KW - Lunar regolith
KW - Ceramics
KW - Microstructure
KW - Sintering
KW - Softening temperature
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592668
DO - https://doi.org/10.1038/s41598-023-50391-y
SN - 2045-2322
VL - 13
SP - 1
EP - 14
PB - Springer Nature
AN - OPUS4-59266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Günster, Jens
A1 - Wang, Gong
A1 - Tian, Xiaoyong
T1 - 3D Printing Technologies for Extreme Environment in Space
N2 - 3D printing technology can realize the rapid fabrication of complicated structures with short production chain, which just meet the requirements for space manufacturing in the future. However, 3D printing technologies in space are still challenging due to the harsh conditions, such as microgravity, high vacuum, and large temperature difference. Meanwhile, in-situ resource utilization and recycling must be considered as a cost effective and resilient resource for 3D printing in space. On the contrary, extreme environmental conditions such as high vacuum and microgravity can also offer significant advantages for advanced materials with high purity and performance. In-situ fabrication of ultra-large components would overcome the weight and structural limitations imposed by rocket launch and change the future strategy for space exploration. The aim of this specially issue is therefore to provide a platform for discussing the potential technologies for 3D printing in space.
KW - Additive Manufacturing
KW - space
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652654
DO - https://doi.org/10.1016/j.amf.2025.200248
SN - 2950-4317
VL - 4
IS - 3
SP - 1
EP - 2
PB - Elsevier
AN - OPUS4-65265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Recknagel, Sebastian
A1 - Richter, Silke
A1 - Hoppe, Marion
A1 - Meckelburg, Angela
A1 - Prinz, Carsten
A1 - Roik, Janina
A1 - Abad Andrade, Carlos Enrique
T1 - Powering precision: development of a certified reference material for elemental composition analysis of lithium nickel manganese cobalt oxide (Li-NMC) cathode material for lithium-ion batteries
N2 - This work presents the development and certification of the world’s first certified reference material (CRM), BAM-S014, for a lithium nickel manganese cobalt oxide (LiNi0.33Mn0.33Co0.33O2 or Li-NMC 111) cathode material—an integral component in high-energy-density lithium-ion batteries that power electric vehicles (EVs), portable electronics, and stationary energy storage systems. By providing certified mass fractions for 11 elements, this CRM addresses a critical need for accurate and traceable elemental analysis, supporting quality control and regulatory compliance in the global battery industry. Ensuring reliable and harmonized measurements supports the efficient use of resources, including the reuse of recycled materials, and ultimately helps maintain product performance and safety. The values were assigned through an interlaboratory comparison involving 16 participating laboratories and various analytical techniques such as inductively coupled plasma optical emission spectrometry (ICP-OES), inductively coupled plasma mass spectrometry (ICP-MS), X-ray fluorescence (XRF) spectrometry, and combustion analysis. In addition to chemical characterization, the certification process includes homogeneity and stability testing of the candidate material. Details are provided on the analytical methods used for chemical characterization and the calculation of the uncertainties of the certified mass fractions. In addition to detailing the development of the CRMs, this work provides an overview of ongoing standardization activities in Li-component analysis, thereby guiding the calibration of analytical methods and contributing to the establishment of globally accepted standards for evaluating energy storage materials and advancing sustainable mobility and clean energy solutions.
KW - Certified reference material
KW - Lithium nickel manganese cobalt oxide
KW - LNMC
KW - Lithium-ion battery
KW - Cathode material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643763
DO - https://doi.org/10.1007/s00216-025-05766-7
SN - 1618-2642
VL - 417
IS - 12
SP - 2643
EP - 2653
PB - Springer Nature
AN - OPUS4-64376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohabbat, Abdulrahman
A1 - Boldog, István
A1 - Reistel, Nils
A1 - de Sousa Amadeu, Nader
A1 - Möllmer, Jens
A1 - Lange, Marcus
A1 - Limon, Aysenur
A1 - Seiffert, Philipp
A1 - Michalski, Julia
A1 - Janiak, Christoph
T1 - P4O10-mediated synthesis of polar polyphosphoric acid-covalent triazine framework composites from aromatic amides for improved water and SO2 sorption
N2 - Polycondensation of various aromatic amides in P4O10 at 400 8C yields covalent triazine frameworks intergrown with a polyphosphoric acid framework (POF-CTFs). Compared to ionothermal analogs, they feature a shorter reaction time and strongly increased framework polarity for water and SO2 uptake, and SO2/CO2
selectivity
KW - COF
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644208
DO - https://doi.org/10.1039/d5cc03419a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Leonhardt, Robert
A1 - Krug von Nidda, Jonas
A1 - Andrae, Dirk
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Tichter, Tim
T1 - Reconstructing the distribution of relaxation times with analytical basis functions
N2 - The present work proposes the implementation of non-singular basis functions into the algorithm for reconstructing the distribution of relaxation times (DRT) function of impedance data. These functions reflect the dispersed and asymmetrical nature of non-ideal capacitive–resistive processes. Inclusion is achieved by combining the singular Debye distribution basis with distributed relaxation functions, such as those derived from the analytical models of Cole–Cole and Havriliak–Negami. The shapes of the introduced basis functions are described by constant parameters, for which an empirical optimization approach is provided alongside. Using synthetic impedance data of non-ideal capacitive–resistive processes subjected to white noise, it is shown that the demand for regularization can be reduced significantly by using distributed bases. To underline the practical relevance of non-singular basis functions in DRT reconstruction, an experimental study comprising 100 sodium-ion and 80 lithium-ion ommercial cells is presented. In this context, it is shown that auxiliary information from the non-ideal nature of real-world electrochemical processes is outsourced into the basis and, hence, easily filtered out of the resulting DRT. This facilitates the separation of single processes without post-DRT curve fitting and thus improves the interpretation
and classification of impedance data significantly.
KW - Electrochemical Impedance Spectroscopy;
KW - Distribution of relaxation times
KW - Basis function
KW - Cole-Cole
KW - Cole-Davidson
KW - Havriliak-Negami
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635486
DO - https://doi.org/10.1016/j.jpowsour.2025.237403
SN - 0378-7753
VL - 652
SP - 1
EP - 11
PB - Elsevier B.V.
AN - OPUS4-63548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bügel, Stefanie
A1 - Hähnel, Malte
A1 - Kunde, Tom
A1 - de Sousa Amadeu, Nader
A1 - Sun, Yangyang
A1 - Spieß, Alex
A1 - Beglau, Thi Hai Yen
A1 - Schmidt, Bernd M.
A1 - Janiak, Christoph
T1 - Synthesis and Characterization of a Crystalline Imine-Based Covalent Organic Framework with Triazine Node and Biphenyl Linker and Its Fluorinated Derivate for CO2/CH4 Separation
N2 - : A catalyst-free Schiff base reaction was applied to synthesize two imine-linked covalent organic frameworks (COFs). The condensation reaction of 1,3,5-tris-(4-aminophenyl)triazine (TAPT) with 4,40-biphenyldicarboxaldehyde led to the structure of HHU-COF-1 (HHU = Heinrich-Heine University). The fluorinated analog HHU-COF-2 was obtained with 2,20,3,30,5,50,6,60-octafluoro 4,40
-biphenyldicarboxaldehyde. Solid-state NMR, infrared spectroscopy, X-ray photoelectron spectroscopy, and elemental analysis confirmed the successful formation of the two network structures. The crystalline materials are characterized by high Brunauer–Emmett–Teller surface areas of 2352 m2/g for HHU-COF-1 and 1356 m2/g for HHU-COF-2. The products of a larger-scale synthesis were applied to prepare mixed-matrix membranes (MMMs) with the polymer Matrimid. CO2/CH4 permeation tests revealed a moderate increase in CO2 permeability at constant selectivity for HHU-COF-1 as a dispersed phase, whereas application of the fluorinated COF led to a CO2/CH4 selectivity increase from 42 for the pure Matrimid membrane to 51 for 8 wt% of HHU-COF-2 and a permeability increase from 6.8 to 13.0 Barrer for the 24 wt% MMM
KW - Separation
KW - COF
KW - MMM
KW - CO2
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618625
DO - https://doi.org/10.3390/ma15082807
VL - 15
IS - 8
SP - 2807
PB - MDPI
AN - OPUS4-61862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaki, Mohammad
A1 - Prinz, Carsten
A1 - Ruehle, Bastian
T1 - A Self-Driving Lab for Nano- and Advanced Materials Synthesis
N2 - The recent emergence of self-driving laboratories (SDL) and material acceleration platforms (MAPs) demonstrates the ability of these systems to change the way chemistry and material syntheses will be performed in the future. Especially in conjunction with nano- and advanced materials which are generally recognized for their great potential in solving current material science challenges, such systems can make disrupting contributions. Here, we describe in detail MINERVA, an SDL specifically built and designed for the synthesis, purification, and in line characterization of nano- and advanced materials. By fully automating these three process steps for seven different materials from five representative, completely different classes of nano- and advanced materials (metal, metal oxide, silica, metal organic framework, and core–shell particles) that follow different reaction mechanisms, we demonstrate the great versatility and flexibility of the platform. We further study the reproducibility and particle size distributions of these seven representative materials in depth and show the excellent performance of the platform when synthesizing these material classes. Lastly, we discuss the design considerations as well as the hardware and software components that went into building the platform and make all of the components publicly available.
KW - Self-driving laboratories
KW - Materials acceleration platforms
KW - Nanomaterials
KW - Advanced materials
KW - Automation
KW - Robotics
KW - In-line characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627361
DO - https://doi.org/10.1021/acsnano.4c17504
SN - 1936-086X
VL - 19
IS - 9
SP - 9029
EP - 9041
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-62736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kossatz, Philipp
A1 - Mezhov, Alexander
A1 - Andresen, Elina
A1 - Prinz, Carsten
A1 - Schmidt, Wolfram
A1 - Resch-Genger, Ute
T1 - Assessing the Applicability of Lanthanide-Based Upconverting Nanoparticles for Optically Monitoring Cement Hydration and Tagging Building Materials
N2 - Chemically stable, lanthanide-based photon upconversion micro- and nanoparticles (UCNPs) with their characteristic multicolor emission bands in the ultraviolet (UV), visible (vis), near-infrared (NIR), and short-wave infrared (SWIR) arepromising optical reporters and barcoding tags. To assess the applicability of UCNPs for the monitoring of early stage cement hydration processes and as authentication tags for cementitious materials, we screened the evolution of the luminescence of Selfmade core-only NaYF4:Yb,Er UCNPs and commercial μm-sized Y2O2S:Yb,Er particles during the first stages of cement hydration, which largely determines the future properties of the hardened material. Parameters explored from the UCNP side included particle size, morphology, surface chemistry or coating, luminescence properties, and concentration in different cement mixtures. From the cement side, the influence of the mineral composition of the cement matrix was representatively examined for ordinary Portland cement (OPC) and its constituents tricalcium aluminate (C3A), tricalcium silicate (C3S), and gypsum at different water to cement ratios. Based on reflection and luminescence measurements, enabling online monitoring, which were complemented by XRD and isothermal heat-flow calorimetric measurements to determine whether the incorporation of these particles could impair cement hydration processes, well suited lanthanide particle reporters could be identified as well as application conditions. In addition, thereby the reporter influence on cement hydration kinetics could be minimized while still preserving a high level of information content. The best performance for the luminescence probing of changes during early stage cement hydration processes was observed for 25 nm-sized oleate (OA)-coated UCNPs added in a concentration of 0.1 wt %. Higher UCNP amounts of 1.0 wt % delayed cement hydration processes size- and surface coatingspecifically in the first 24 h. Subsequent luminescence stability screening studies performed over a period of about one year support the applicability of UCNPs as optical authentication tags for construction materials.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Quantum yield
KW - NIR
KW - Mechanism
KW - Characterization
KW - XRD
KW - Calorimetry
KW - Advanced material
KW - Cement
KW - Monitoring
KW - Surface
KW - Size
KW - Lifetime
KW - Barcode
KW - Lanthanide
KW - Upconversion
KW - Encoding
KW - Method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638318
DO - https://doi.org/10.1021/acsomega.5c02236
SN - 2470-1343
VL - 10
IS - 29
SP - 31587
EP - 31599
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-63831
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chouquet, Xavier
A1 - Bolten, Julia
A1 - Prinz, Carsten
A1 - Günster, Jens
A1 - Zocca, Andrea
ED - Vincenzini, P.
T1 - Direct ink writing of zeolite-like AQSOA Z02 for envisioned applications in solar-driven atmospheric water harvesting: Paste formulation and effect of thermal treatments on the water sorption propertie
N2 - This work presents the development of porous water adsorbent bodies with complex geometries shaped by direct ink writing additive manufacturing. AQSOA FAM Z02 (Z02), a commercial material similar to SAPO-34 with chabazite structure, was selected as sorbent material. Dynamic vapor sorption analysis demonstrated that Z02 adsorbs and desorbs up to 30 % of its own mass in each cycle, highlighting its potential for this application. To optimize its printability for direct ink writing, aqueous pastes composed of Z02 and bentonite were formulated. Bentonite served as the inorganic binder and was responsible for the mechanical stability of the printed porous bodies after heat treatment. The most suitable paste composition was identified and used to fabricate scaffold structures. These structures were then subjected to different heat treatments at 650 °C, 750 °C and 850 °C to find a suitable compromise between mechanical stability and retention of the sorption properties. Scaffold structures printed with a 20 wt% of bentonite binder were mechanically stable (1.9 ± 1.1 MPa compressive strength) and retained a maximum water uptake of ca. 25 wt% after heat treatment at 750 °C for 1 h.
KW - Direct ink writing
KW - Zeolite
KW - Direct ink wriDynamic vapor sorption
KW - Bentonite Water harvesting
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643150
DO - https://doi.org/10.1016/j.ceramint.2025.09.314
SN - 0272-8842
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-64315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Appel, Paul Alexander
A1 - Prinz, Carsten
A1 - Low, Jian Liang
A1 - Asres, Nahom Enkubahri
A1 - Wu, Shu-Han
A1 - Freytag, Annica
A1 - Krug von Nidda, Jonas
A1 - de Sousa Amadeu, Nader
A1 - Fellinger, Tim-Patrick
T1 - Kern–Schale: Versiegelung nanoporöser Partikel mit semipermeablen Kohlenstoffschichten befreit Hartkohlenstoffanoden von ihrem Dilemma
N2 - In der vorliegenden Arbeit wird eine Kern-Schale-Strategie vorgestellt, die das grundlegende Problem gängiger nichtgraphitischer Hartkohlenstoff-Anoden adressiert: Hohe reversible Kapazitäten gehen bislang typischerweise mit erheblichen irreversiblen Verlusten in den ersten Zyklen einher. Analog zu Graphit, das sowohl Lithiumspeicherung als auch die Abtrennung von Elektrolytlösungsmitteln in einer homogenen Struktur vereint, zeigen wir, dass sich diese beiden Funktionen auch in nichtgraphitischen Kohlenstoffen gezielt in einer heterogenen Architektur kombinieren lassen. Hochporöse Aktivkohlen werden durch kinetisch kontrollierte Gasphasenabscheidung mit einer dünnen Schicht nichtgraphitischen Kohlenstoffs überzogen, sodass eine funktionale Kern-Schale-Struktur entsteht. Gasadsorptionsmessungen an Kern-, Schalen-, Kern-Schale- und mechanisch beschädigte Kern-Schale-Partikeln, bestätigen, dass die Porosität des Kerns erhalten bleibt und die Schale semipermeabel ist. Die Sorption von Diethylcarbonat wird als geeignetere Methode im Vergleich zu N2- oder CO2-Sorptionsmessungen eingeführt, um die irreversiblen Verluste des ersten Zyklus mit der tatsächlichen Flüssig-Fest-Grenzfläche von Kohlenstoffanoden zu verknüpfen. Die funktionalen Kern-Schale-Partikel zeigen eine stark reduzierte Aufnahme von Diethylcarbonat, was hohe reversible Kapazitäten bei deutlich geringeren Erstzyklusverlusten ermöglicht. Bei einer reversiblen Kapazität von 400 ± 24 mAh g−1 und einer initialen Coulombeffizienz von 82 ± 2% zeigt sich, dass die dreistufige Natriumspeicherung in der gezielt entwickelten Kern-Schale-Architektur den größeren Ionenradius von Natrium gegenüber Lithium (372 mAh g−1 in Graphit) kompensieren kann. Die entwickelten Kern-Schale-Anoden erreichen damit ein Leistungsniveau, das für eine kommerzielle Anwendung vielversprechend ist.
KW - Kern-Schale-Struktur
KW - Natriumionenbatterie
KW - Hartkohlenstoffanode
KW - Diethylcarbonatdampfsorption
KW - Aktivkohle
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655354
DO - https://doi.org/10.1002/ange.202519457
SN - 1521-3757
N1 - Es gibt eine parallele Sprachausgabe (englisch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (English), a link is in the field related identifier
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65535
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Appel, Paul Alexander
A1 - Prinz, Carsten
A1 - Low, Jian Liang
A1 - Asres, Nahom Enkubahri
A1 - Wu, Shu-Han
A1 - Freytag, Annica
A1 - Krug von Nidda, Jonas
A1 - de Sousa Amadeu, Nader
A1 - Fellinger, Tim-Patrick
T1 - Core‐Shell: Resolving the Dilemma of Hard Carbon Anodes by Sealing Nanoporous Particles With Semi‐Permeable Coatings
N2 - A core-shell strategy is introduced to overcome the dilemma of common non-graphitic hard carbon anodes, linking high reversible storage capacity to practically unacceptable irreversible losses in the first cycle(s). Just as Graphite homogeneously combines effective lithium storage with an electrolyte solvent-sieving function, we show that both of these functions could be strategically integrated into non-graphitic carbons in a heterogeneous structure. Highly porous activated carbons are sealed by kinetically tuned gas-phase deposition of non-graphitic carbon to form a functional core-shell structure. Gas sorption porosimetry on core, shell, core–shell, and cracked core-shell particles confirms preserved core porosity and a semi-permeable shell. Diethyl carbonate sorption analysis is introduced as a more suitable probe than N2 or CO2 sorption, linking first-cycle losses to the liquid–solid interface of carbon anodes. The functional core-shell particles with much reduced diethyl carbonate uptake allow for high storage capacity and reduced first cycle losses. Delivering 400 ± 24 mAh g−1 with 82 ± 2% first-cycle reversibility, it is shown that three-stage Na storage in designed core-shell anodes can compensate for the larger size of sodium compared to lithium stored in graphite anodes (372 mAh g−1). The designed core-shell anodes show state-of-the-art performance with commercial promise.
KW - Sodium-ion battery
KW - Activated carbon
KW - Core-shell
KW - Hard carbon anode
KW - Diethyl carbonate vapor sorption
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655346
DO - https://doi.org/10.1002/anie.202519457
SN - 1433-7851
N1 - Es gibt eine parallele Sprachausgabe (deutsch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (German), a link is in the field related identifier
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falk, Florian
A1 - Menneken, M.
A1 - Stephan-Scherb, Christiane
T1 - Real-time observation of high- temperature gas corrosion in dry and wet SO2-containing atmosphere
N2 - Sulfur and water have a fundamental impact on the corrosion rate and potential failure of materials. It is therefore necessary to understand the mechanisms, rates, and potential means of transport, as well as the reactions of these elements with an alloy. This paper investigates the effect of water vapor in the initial stages of SO2 corrosion of an Fe-9Cr-0.5Mn model alloy at 650°C in situ under laboratory conditions using energy-dispersive x-ray diffraction analysis. Two separate experiments were run, one with a 99.5% Ar + 0.5% SO2 atmosphere and one with a 69.5% Ar + 0.5% SO2 + 30% H2O atmosphere. With a wet atmosphere, the alloy formed a scale with decreasing oxygen content towards the scale–alloy interface. Sulfides were identified above and below a (Fe, Cr)3O4 layer in the inner corrosion zone. In contrast to this, the overall scale growth was slower in a dry SO2 atmosphere.
KW - Early oxidation
KW - Early sulfidation
KW - Ferritic steels
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472844
UR - https://link.springer.com/article/10.1007/s11837-019-03335-9#enumeration
DO - https://doi.org/10.1007/s11837-019-03335-9
SN - 1047-4838
SN - 1543-1851
VL - 71
SP - 1
EP - 6
PB - Springer
CY - New York
AN - OPUS4-47284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - An, Biwen Annie
A1 - Shen, Y.
A1 - Voordouw, J.
A1 - Voordouw, G.
T1 - Halophilic methylotrophic methanogens may contribute to the high ammonium concentrations found in shale oil and shale gas reservoirs
N2 - Flow-back and produced waters from shale gas and shale oil fields contain high ammonium, which can be formed by methanogenic degradation of methylamines into methane and ammonium. Methylamines are added to fracturing fluid to prevent clay swelling or can originate from metabolism of the osmolyte triglycinebetaine (GB).
We analyzed field samples from a shale gas reservoir in the Duvernay Formation and from a shale oil reservoir in the Bakken formation in Canada to determine the origin of high ammonium. Fresh waters used to make fracturing fluid, early flow-back waters, and late flow back waters from the shale gas reservoir had increasing salinity of 0.01, 0.58, and 2.66 Meq of NaCl, respectively. Microbial community analyses reflected this fresh water to saline transition with halophilic taxa including Halomonas, Halanaerobium, and Methanohalophilus being increasingly present. Early and late flow-back waters had high ammonium concentrations of 32 and 15 mM, respectively.
Such high concentrations had also been found in the Bakken produced waters.
Enrichment cultures of Bakken produced waters in medium containing mono, di-, or trimethylamine, or triglycinebetaine (GB) converted these substrates into ammonium (up to 20 mM) and methane. The methylotrophic methanogen Methanohalophilus, which uses methylamines for its energy metabolism and uses GB as an osmolyte, was a dominant community member in these enrichments. Halanaerobium was also a dominant community member that metabolizes GB into trimethylamine, which is then metabolized further by Methanohalophilus. However, the micromolar concentrations of GB measured in shale reservoirs make them an unlikely source for the 1,000-fold higher ammonium concentrations in flow-back waters. This ammonium either originates directly from the reservoir or is formed from methylamines, which originate from the reservoir, or are added during the hydraulic fracturing process. These methylamines are then converted into ammonium and methane by halophilic methylotrophic methanogens, such as Methanohalophilus, present in flow-back waters.
KW - Methanogen
KW - Oil and gas industry
KW - Shale
KW - Halophile
KW - Corrosion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474982
DO - https://doi.org/10.3389/fenrg.2019.00023
SN - 2296-598X
VL - 7
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-47498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Sascha
A1 - Jäger, L. A.
A1 - Karapanagiotis, Christos
A1 - Münzenberger, Sven
A1 - Kowarik, Stefan
T1 - Real-time dynamic strain sensing in optical fibers using artificial neural networks
N2 - We propose to use artificial neural networks (ANNs) for raw measurement data interpolation and signal shift computation and to demonstrate advantages for wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) and dynamic strain distribution measurement along optical fibers. The ANNs are trained with synthetic data to predict signal shifts from wavelength scans. Domain adaptation to measurement data is achieved, and standard correlation algorithms are outperformed. First and foremost, the ANN reduces the data analysis time by more than two orders of magnitude, making it possible for the first time to predict strain in real-time applications using the WS-COTDR approach. Further, strain noise and linearity of the sensor response are improved, resulting in more accurate measurements. ANNs also perform better for low signal-to-noise measurement data, for a reduced length of correlation input (i.e., extended distance range), and for coarser sampling settings (i.e., extended strain scanning range). The general applicability is demonstrated for distributed measurement of ground movement along a dark fiber in a telecom cable. The presented ANN-based techniques can be employed to improve the performance of a wide range of correlation or interpolation problems in fiber sensing data analysis and beyond.
KW - Distributed vibration sensing
KW - Distributed acoustic sensing
KW - Coherent optical time domain reflectometry
KW - Optical fiber sensor
KW - Artificial neural network
KW - Real time measurement
KW - Distributed strain sensing
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474832
UR - https://www.osapublishing.org/oe/abstract.cfm?uri=oe-27-5-7405
DO - https://doi.org/10.1364/OE.27.007405
SN - 1094-4087
VL - 27
IS - 5
SP - 7405
EP - 7425
PB - Optical Society of America
AN - OPUS4-47483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Palkowski, Carsten
A1 - Zottl, A.
A1 - Malenkovic, I.
A1 - Simo, Anne
T1 - Fixing efficiency values by unfixing compressor speed: Dynamic test method for heat pumps
N2 - The growing market penetration of heat pumps indicates the need for a performance test method that better reflects the dynamic behavior of heat pumps. In this contribution, we developed and implemented a dynamic test method for the evaluation of the seasonal performance of heat pumps by means of laboratory testing. Current standards force the heat pump control inactive by fixing the compressor speed. In contrast, during dynamic testing, the compressor runs unfixed while the heat pump is subjected to a temperature profile. The profile consists of the different outdoor temperatures of a typical heating season based on the average European climate and also includes temperature changes to reflect the dynamic behavior of the heat pump. The seasonal performance can be directly obtained from the measured heating energy and electricity consumption making subsequent data interpolation and recalculation with correction factors obsolete. The method delivers results with high precision and high reproducibility and could be an appropriate method for a fair rating of heat pumps.
KW - Heat pump
KW - Dynamic test method
KW - Seasonal performance factor
KW - Variable frequency drive
KW - Energy label
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476944
DO - https://doi.org/10.3390/en12061045
SN - 1996-1073
VL - 12
IS - 6
SP - 1045, 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-47694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, David
A1 - Ou, D.
A1 - Ghafafian, Carineh
A1 - Zscherpel, Uwe
A1 - Trappe, Volker
T1 - Wind turbine rotor blade testing by dual-energy laminography
N2 - Modern wind turbine rotor blades consist of sandwich shell segments made from glass fiber reinforced polymers. During manufacturing, defects can arise which could lead to failure of the whole component under dynamic mechanical and thermal loads. Hence during operation defects can arise which, if detected, can be repaired locally and in-situ by applying repair patches instead of taking the whole rotor blade down and repair it remotely. This method is much more time and cost effective, since the shut-down time of the energy converter is limited to a minimum. These repair patches can, however, also lead to new defects if not applied optimally. Therefore, it is necessary to control the quality of the repair patches to ensure the best possible restoration of structural integrity of the component. As a rotor blade is an object with a large aspect ratio, X-ray laminography is predestined to provide 3D information of the objective volume. To enhance the amount of information gained from laminographic reconstruction, we use in this study a photon counting and energy discriminating X-ray detector and apply a material decomposition algorithm to the data. By inherently separating the incident spectra within the detection process into two distinct energy bins, the basis material decomposition can provide material resolved images. Choosing glass and epoxy resin as basis materials and numerically solving the inverse dual-energy equation system, the reconstructed laminographic datasets contain highly valuable information about the distribution of the basis materials within the structure. Furthermore, cross- artifacts arising from the limited angle of the projection data can be reduced by this method which allows to investigate structures that were hidden underneath the artefacts.
T2 - International Symposium on Digital Industrial Radiology and Computed Tomography – DIR2019
CY - Fürth, Germany
DA - 02.07.2019
KW - Laminography
KW - Wind energy
KW - Fiber reinforced polymer
KW - Photon counting detector
KW - Repair patch
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484380
UR - https://www.dir2019.com/portals/dir2019/bb/Tu.3.A.1.pdf
SN - 978-947971-06-0
SP - 1
EP - 13
AN - OPUS4-48438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Palkowski, Carsten
A1 - Schwarzenberg, S.
A1 - Simo, Anne
T1 - Seasonal cooling performance of air conditioners: The importance of independent test procedures used for MEPS and labels
N2 - Minimum energy performance standards and labels are commonly used tools to reduce the household energy use thus mitigating greenhouse gas emissions. However, the technical foundation for minimum energy performance standards and labels are test procedures for rating and testing of appliances. To de- termine the seasonal cooling performance of air conditioners, the current test standards require fixing of the compressor speed of the units to achieve steady-state conditions; this way of operation, how- ever, differs from real-life use. To make the seasonal cooling performance testing better reflect the real use conditions, this study proposes a compensation method which can be conducted independently from manufacturer data and still allows modulation of the tested units. Our results show that the tested units behave differently under part-load conditions, which results in a lower energy efficiency rating for some of the tested devices.
KW - Air conditioner
KW - Independent test method
KW - Real use behavior
KW - Seasonal energy efficiency ratio
KW - Minimum energy performance standards
KW - Energy label
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485813
DO - https://doi.org/10.1016/j.ijrefrig.2019.05.021
SN - 0140-7007
VL - 104
SP - 417
EP - 425
PB - Elsevier
AN - OPUS4-48581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knieschewski, Arno
A1 - Stamminger, R.
A1 - Simo, Anne
T1 - Cost analysis of screening methods to find non-compliant models using the example of tumble dryers
N2 - The European energy label was established to reduce energy consumption in Europe. All classes and values on the energy label are stated by the supplier. The task of market surveillance is to ensure correct labels and to validate their values through compliance tests. However, this can only be done for a small fraction of all models on the market, since physical tests are expensive. Screening methods can be used to narrow down the number of critical products before compliance tests are done to decrease the costs of finding non-compliant models.
This study shows a mathematical approach to analyze the cost benefits of screening methods to find non-compliant models. Furthermore, the analysis presented has been applied to 18 screening methods for tumble dryers. The performance test for tumble dryers consists of seven test runs. All screening methods evaluated are composed of a reduced number of test runs. The most efficient screening method reduces the surveillance costs by 40 %.
KW - Screening method
KW - Market surveillance
KW - Tumble dryer
KW - Energy label
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486762
DO - https://doi.org/10.1007/s12053-019-09805-y
SN - 1570-646X
SN - 1570-6478
VL - 12
IS - 7
SP - 1707
EP - 1715
PB - Springer
CY - Dordrecht
AN - OPUS4-48676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Liehr, Sascha
A1 - Münzenberger, Sven
A1 - Krebber, Katerina
T1 - Wavelength-scanning distributed acoustic sensing for structural monitoring and seismic applications
N2 - We introduce wavelength-scanning coherent optical time domain reflectometry (WS-COTDR) for dynamic vibration sensing along optical fibers. The method is based on spectral shift computation from Rayleigh backscatter spectra. Artificial neural networks (ANNs) are used for fast and high-resolution strain computation from raw measurement data. The applicability of the method is demonstrated for vibration monitoring of a reinforced concrete bridge. We demonstrate another application example for quasi-static and dynamic measurement of ground deformation and surface wave propagation along a dark fiber in a telecommunication cable.
T2 - 7th International Symposium on Sensor Science
CY - Napoli, Italy
DA - 09.05.2019
KW - Optical fiber sensor
KW - Distributed acoustic sensor (DAS)
KW - Optical time domain reflectometry
KW - Rayleigh scattering
KW - Artificial neural networks
KW - Structural health monitoring
KW - Seismic measurement
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487733
DO - https://doi.org/10.3390/proceedings2019015030
SN - 2504-3900
VL - 15
SP - Paper 30, 1
EP - 5
PB - MDPI
CY - Basel
AN - OPUS4-48773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schneider, Ronald
T1 - Effect of repair models on risk based optimal inspection strategies for support structures of offshore wind turbines
N2 - Owners or operators of offshore wind farms perform inspections to collect information on the condition of the wind turbine support structures and perform repairs if required. These activities are costly and should be optimized. Risk-based methods can be applied to identify inspection and repair strategies that ensure an optimal balance between the expected total service life cost of inspection and repair, and the achieved risk reduction. Such an optimization requires explicit modeling of repairs. In this paper, the impact of different repair models on the results of a risk-based optimization of inspection and repair strategies is quantified in a numerical example considering a jacket-type steel frame subject to high-cycle fatigue. The example showed that, in this specific application, there is no need for detailed modeling of the behavior of repaired welded connections.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019)
CY - Potsdam, Germany
DA - 27.08.2019
KW - Risk
KW - Reliability
KW - Inspection planning
KW - Offshore wind turbines
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488297
UR - https://www.smar2019.org/Portals/smar2019/bb/Th.2.A.4.pdf
SP - Paper Th.2.A.4, 1
EP - 8
AN - OPUS4-48829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüsken, Götz
A1 - Shamsuddoha, Md
A1 - Thiele, Marc
A1 - Baeßler, Matthias
A1 - Kühne, Hans-Carsten
T1 - Comparison of cracks formed in scaled grouted connection of offshore energy structures under static and cyclic loads
N2 - Global energy consumption will increase in the future necessitating both fossil fuels and renewable energy choices - especially wind energy. Such high energy demand requires installation of offshore energy structures, rigs, platforms and towers, which are susceptible to adverse environmental conditions along with maintenances. Due to their large size and remote locations, cylindrical grouted joints are often adopted between substructure and foundation in these offshore platforms and wind structures such as monopiles. However, these connections are composite structures with exterior sleeve, interior pile and infill mortar. Degradation and settlements were reported inside similar connections, which were installed in last three decades. Besides, grouting in the offshore sites were proven difficult to obtain ideal load bearing capacity. In-situ loading conditions were also found to be affecting the failure mechanism inside such connections. This study aims at characterizing the nature of cracks generated in these grouted connections under both static and cyclic loading. Scaled grouted joints were manufactured using a novel reusable mold, and connections were loaded to failure to visualize the main failure patterns. An assessment between failure under these two types of load is drawn along with comparison to previously available literature.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.2019
KW - Grouted connection
KW - Crack formation
KW - Crack pattern
KW - Static load
KW - Cyclic load
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487961
SP - Th.2.A.1-1
EP - Th.2.A.1-9
AN - OPUS4-48796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kullolli, Borana
A1 - Cuéllar, Pablo
A1 - Baeßler, Matthias
A1 - Stutz, H. H.
T1 - Modelling and calibration for cyclic soil-structure interface behaviour
N2 - The structural performance of many geotechnical systems (e.g. axially-loaded pile foundations), depends on the shearing resistance at the soil interface, which may govern the load bearing capacity of the foundation. Experimental investigations have shown that this interaction is mainly localised within a narrow shear band next to the structure. Under cyclic loading, a contraction of the soil at the interface may arise (net volume loss), possibly leading to a stress relaxation and thus to a reduction of the load bearing capacity (the so-called friction fatigue). Based on the constitutive similarities between soil continua and interfaces, we propose here the adaption of a Generalized Plasticity model for sandy soils for the numerical analysis of interface problems. In this contribution, the results of an experimental campaign for the parameter calibration of the constitutive model are presented. The tests have been conducted with a ring shear device involving different normal stresses, roughness of the steel plates as well as cyclic loading. The new modelling approach shows promising results and has the additional practical advantage that the interface zone and the soil continuum can both be described with the same constitutive model in general boundary value problems.
T2 - Konferenz 7th International Symposium on Deformation Characteristics of Geomaterials
CY - Glasgow, Scotland
DA - 26.06.2019
KW - Soil-structure interaction
KW - Offshore foundations
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489096
DO - https://doi.org/10.1051/e3sconf/20199213007
VL - 92
SP - 13007
EP - 13013
PB - EDP Sciences
CY - Glasgow, Scotland
AN - OPUS4-48909
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Babutzka, Martin
T1 - Investigation of the salinization in marine and offshore environment - test methods and challenges
N2 - Salinization and contamination of metal surfaces by chloride-containing aerosols is of great importance with regard to corrosion phenomena in the maritime sector and in offshore applications. Especially Offshore Wind Turbines are exposed to extreme corrosive conditions due to high chloride concentrations in the atmosphere and the resulting high chloride deposition rates. It is of great importance to evaluate to what extent salinization of the surface influences the corrosion protection of coatings and pitting occurrence on stainless steels under atmospheric conditions to evaluate the durability of metallic building structures in offshore and marine environments. The evaluation of the scientific literature and regulatory guidelines has shown that there are still many open questions regarding the contamination of metal surfaces by chlorides. This contribution will discuss how salinization of metal surfaces is evaluated and monitored according to current standards and guidelines. Future challenges concerning test methods and the application of evaluated salinization values and deposition rates will be discussed.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.20019
KW - Maritime Atmosphäre
KW - Versalzung
KW - Maritime atmosphere
KW - Salinization
PY - 2019
SP - Th.2.A.5, 1
EP - 8
PB - SMAR 2019
AN - OPUS4-48905
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Pohl, Rainer
A1 - Lohde, Sebastian
A1 - Aydoğdu, M.
T1 - Zerstörungsfreie Prüfung von Composite-Druckgefäßen mit konventioneller und hochfrequenter Wirbelstromtechnik
N2 - Composite-Druckgefäße für den Gefahrguttransport sowie für Wasserstoff- und Erdgasfahrzeuge bestehen aus einem lasttragenden Composite und einer gasdichten, metallischen oder polymeren Barriereschicht (Liner). Zur Untersuchung des Alterungsverhaltens solcher Composite-Druckgefäße wurde in der BAM das interdisziplinäre Themenfeldprojekt COD-AGE durchgeführt. Ziel des Projektes war die Entwicklung von Methoden und Modellen zur Beschreibung und Bestimmung des Alterungsverhaltens von Carbonfaser-Compositen am Beispiel von Druckgefäßen, um eine bessere Vorhersage der Alterung und der sicheren Gebrauchsdauer zu ermöglichen. Ein Schwerpunkt in diesem Projekt war die Bereitstellung geeigneter ZfP-Methoden. Dabei ging es sowohl um versuchsbegleitende Prüfungen, als auch um die mögliche Entwicklung von Prüfeinrichtungen für den späteren praktischen Gebrauch.
In dem Vortrag werden Prüfergebnisse der alterungsbegleitenden Wirbelstromprüfung an Composite-Druckgefäßen vorgestellt.
In Alterungsversuchen wurden Druckgefäße aus einem ca. 4 mm dicken Aluminiumliner und ca. 8 mm dicker CFK-Ummantelung untersucht. Typisches Einsatzgebiet solcher Druckgefäße sind Atemschutzgeräte der Feuerwehr. Die Druckgefäße wurden sowohl mit konventioneller Wirbelstromtechnik von außen und von innen als auch mit hochfrequenter Wirbelstromtechnik von außen geprüft. Es konnten sowohl Beschädigungen des metallischen Liners, als auch Strukturen des CFK-Geflechts nachgewiesen werden. Eine besondere mechanische Herausforderung bestand in der Prüfung der Innenseite der Liner, da hier eine zylindrische Fläche mit einem Innendurchmesser von 150 mm durch einen Zugang von nur 15 mm Durchmesser geprüft werden muss.
T2 - DACH-Jahrestagung
CY - Friedrichshafen, Germany
DA - 26.05.2019
KW - Wirbelstromprüfung
KW - COD-AGE
KW - Composite-Druckgefäß
KW - CFK
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481243
SN - 978-3-947971-02-2
VL - 171
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-48124
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Ghigo, Tea
A1 - Rabin, Ira
ED - Buzi, P.
T1 - Detecting Early Medieval Coptic literature in Dayr Al-Anba Maqar, Between textual conservation and literary rearrangement: The case of Vat. Copt. 57
N2 - The study of the VAt.Copt. 57 at the Vatican Library. Codicological, palaeographical, textual and archaeometrical considerations.
KW - Coptic
KW - Archaeometry
KW - Ink
KW - Manuscripts
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494004
SN - 978-88-210-1025-5
SP - 77
EP - 83
PB - Biblioteca Apostolica Vaticana
AN - OPUS4-49400
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Dussert, F.
A1 - Truffier-Boutry, D.
A1 - Benayad, A.
A1 - Beal, D.
A1 - Mattera, L.
A1 - Ling, W. L.
A1 - Carrière, M.
A1 - Reiss, P.
T1 - Influence of the Core/Shell Structure of Indium Phosphide Based Quantum Dots on Their Photostability and Cytotoxicity
N2 - With the goal to improve their photostability, InP-based QDs are passivated with three types of inorganic shells, namely (i) a gradient ZnSexS1−x shell, (ii) an additional ZnS shell on top of the gradient shell with two different thicknesses (core/shell/shell, CSS), (iii) an alumina coating on top of ZnS. All three systems have photoluminescence Quantum yields (PLQY) > 50%and similar PL decay times (64–67 ns). To assess their photostability they are incorporated into a transparent poly (methyl methacrylate) (PMMA) matrix and exposed to continuous irradiation with simulated sunlight in a climate chamber. The alumina coated core/shell system exhibits the highest stability in terms of PLQY Retention as well as the lowest shift of the PL maximum and lowest increase of the PL linewidth, followed by the CSS QDs and finally the gradient shell system. By means of XPS studies we identify the degradation of the ZnS outer layer and concomitant xidation of the emissive InZnP core as the main origins of degradation in the gradient structure. These modifications do not occur in the case of the alumina-capped sample, which exhibits excellent chemical stability. The gradient shell and CSS systems could be transferred to the aqueous phase using surface ligand exchange with penicillamine. Cytotoxicity studies on human primary keratinocytes revealed that exposure for 24 h to 6.25–100 nM of QDs did not affect cell viability. However, a trend toward reduced cell proliferation is observed for higher concentrations of gradient shell and CSS QDs with a thin ZnS shell, while CSS QDs with a thicker ZnS shell do not exhibit any impact.
KW - Indium phosphide
KW - Quantum dots
KW - Cytotoxicity
KW - Photostability
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494249
DO - https://doi.org/10.3389/fchem.2019.00466
VL - 7
SP - Article Number: 466
PB - Frontiers Media SA
AN - OPUS4-49424
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Otto, Peter
A1 - de Lorenzis, L.
A1 - Unger, Jörg F.
T1 - Explicit dynamics in impact simulation using a NURBS contact interface
N2 - In this paper, the impact problem and the subsequent wave Propagation are considered. For the contact discretization an intermediate non-uniform rational B-spline (NURBS) layer is added between the contacting finite element bodies, which allows a smooth contact formulation and efficient element-based integration.
The impact event is ill-posed and requires a regularization to avoid propagating stress oscillations. A nonlinear mesh-dependent penalty regularization is used, where the stiffness of the penalty regularization increases upon mesh refinement. Explicit time integration methods are well suited for wave propagation problems, but are efficient only for diagonal mass matrices. Using a spectral element discretization in combination with a NURBS contact layer the bulk part of the mass matrix is diagonal.
KW - Explicit dynamics
KW - Impact simulation
KW - Isogeometric analysis
KW - mortar method
KW - spectral elements
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506041
DO - https://doi.org/10.1002/nme.6264
VL - 121
IS - 6
SP - 1248
EP - 1267
PB - Wiley Online Libary
AN - OPUS4-50604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zinke, R.
A1 - Virothi, N.
A1 - Köhler, F.
A1 - Klippel, A.
A1 - Schalau, Sebastian
A1 - Krause, U.
T1 - Experimental measurement of initial evaporation mass flows from gasoline spills and comparison with empirical models
N2 - In this paper, we investigate the evaporation mass flow originating from spills of gas-oline. Large spills of gasoline may form during partial or complete roof sinkings or inthe case of perforations at various deck fittings at external floating roof tanks usedfor the storage. Additionally, spills may form in the retention area in the case of leak-ages at pipes or at the hull. The aim is to predict the order of magnitude of real-scaleevaporation mass flow. The determined evaporation mass flows will be used in arelated project as input values for subsequent dispersion modeling in the vicinity ofthe tanks. This is relevant for questions of fire and explosion protection as well as forenvironmental protection aspects in tank farms or refineries, which use externalfloating roof tanks. The measurements presented in this paper were compared withpredictions by empirical models and investigations of evaporations from small floorspills, round-bottom flask, or from Petri dishes published in the literature. The maingoal of this paper is to test the applicability of empirical models to provide reasonableevaporation mass flows as input for CFD dispersion simulations.
KW - Spill evaporation
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504322
DO - https://doi.org/10.1002/prs.12128
VL - 39
IS - 3
SP - e12128
PB - Wiley Online Libary
AN - OPUS4-50432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kapa, Thomas
A1 - Schreier, Andy
A1 - Krebber, Katerina
T1 - A 100-km BOFDA Assisted by First-Order Bi-Directional Raman Amplification
N2 - We present, to our knowledge for the first time, a 100-km Brillouin Optical Frequency-Domain Analysis (BOFDA) employing a 200-km fiber loop. Compared to our previous publication, enhanced sensor length, sensor accuracy and spatial resolution are presented. The performance improvements are achieved by applying distributed Raman amplification (DRA) and a digital high-pass filter. We report on temperature measurements over sensing distances of 75 km and 100 km both with a 12.5-m spatial resolution. Temperature changes of 5 °C have been measured along 75 km sensing fiber. A temperature change of 30 °C has been detected at 99.5 km.
KW - Distributed sensing
KW - Fiber optics sensors
KW - Stimulated Brillouin scattering
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476577
DO - https://doi.org/10.3390/s19071527
SN - 1424-8220
VL - 19
IS - 7
SP - 1527, 1
EP - 9
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-47657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
A1 - Habib, Abdel Karim
T1 - Frequenzanalyse von Schallemission an einem Stahlrohr unter Biegebeanspruchung
N2 - Um ein tieferes Verständnis über die Schallemission bei der Entstehung und Ausbreitung von Rissen in Stahlrohrleitungen zu erlangen, wurde ein Stahlrohr der Güte S355J2H im Vierpunkt-Biegeversuch quasistatisch bis hin zum Wanddurchbruch (Leckage) belastet und mittels Schallemissionsmessung und Gleichstrompotentialmessung überwacht. Das Rohrsegment wurde durch einen 90°- Außenumfangskerb in der Mitte der Rohrlänge definiert vorgeschädigt, um davon ausgehend ein stabiles Risswachstum zu induzieren und die Analyse von Schallemission aus Rissereignissen, die am Kerb eintraten, sicherzustellen. Für die Schallemissionsmessung wurden vier Breitbandsensoren max. 105 mm vom Kerb entfernt montiert. Die Signalaufzeichnung erfolgte kontinuierlich und schwellwertunabhängig. Für die Gleichstrompotentialmessung wurde ein Gleichstrom von 300 A eingeleitet und der Potentialabfall über dem Kerb mit fünf Sonden entlang des Kerbs gemessen. Beide Messverfahren identifizieren die Rissinitiierung sowie Veränderungen im Risswachstum. Die detektierten Schallemissionsereignisse werden, unter Berücksichtigung spektraler Eigenschaften, mit fortschreitender Belastung und Rissentwicklung analysiert. Diese Studien wurden im Rahmen des interdisziplinären Forschungsprojekts AGIFAMOR, Aging infrastructure - Faseroptisches Monitoring von Rohrleitungen, an der BAM durchgeführt.
T2 - 22. Kolloquium Schallemission und 3. Anwenderseminar Zustandsüberwachung mit geführten Wellen
CY - Karlsruhe, Germany
DA - 27.03.2019
KW - Schallemission
KW - Frequenzanalyse
KW - Rissbildung in Stahl
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476888
SN - 978-3-947971-00-8
VL - 169
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-47688
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Gründer, Klaus-Peter
A1 - Kadoke, Daniel
A1 - Unger, Jörg F.
T1 - Überwachung von Stahlbetonbrücken - Ein Modellprojekt
N2 - Die Brücken im Netz der Bundesverkehrswege sind überwiegend in einem ausreichenden bis guten Zustand. Allerdings steigt der Unterhalts- und Sanierungsaufwand aufgrund des inzwischen hohen Alters vieler Brücken sowie des ständig wachsenden Schwerlastverkehrs. Techniken zur Einschätzung der verbleibenden Lebensdauer von Brücken sowie zur dauerhaften Beobachtung des Tragverhaltens bzw. des Erfolges von Sanierungsmaßnahmen werden daher für den sicheren und wirtschaftlichen Betrieb dringend benötigt. Zur Evaluierung dafür geeigneter holistischer Ansätze wurde in der BAM das Projekt BLEIB - Bewertung, Lebensdauerprognose und Instandsetzung von Brückenbauwerken - ins Leben gerufen.
Ein zentrales Ergebnis des Projektes ist eine extern vorgespannte Stahlbetonbrücke als Zweifeldträger mit einer Gesamtlänge von 24 m, die für den Test verschiedenster Sensorsysteme, zur Validierung numerischer Modelle und zur Erprobung von Sanierungs- und Verstärkungsmaßnahmen entwickelt wurde. Für die Simulation unterschiedlicher Schädigungsgrade kann die Vorspannung der Brücke variiert werden. Die Brücke wird mit beweglichen Gewichten belastet und über einen Shaker zum Schwingen angeregt.
Das Brückenmodell wurde bewusst geschädigt, indem die Vorspannung der Struktur erstmalig schrittweise bis auf null reduziert wurde. Unter der Eigenlast verformte sich die Brücke, wodurch eine Rissbildung im Beton einsetzte. Die Zugspannung, die zuvor durch die Vorspannung aufgenommen wurde, übernahm Schritt für Schritt der Beton. Als die Zugspannungen die relativ geringe Zugfestigkeit des Betons überstiegen, begann dieser zu reißen und die schlaffe Bewehrung der Struktur nahm die Spannungen auf. Dieser Versuch wurde unter anderem von Schallemissionsmessungen begleitet. Der Rissbildungsprozess konnte damit, bei gleichzeitiger Aufzeichnung der Vorspannung, früh detektiert und die Risse geortet werden. Die Ergebnisse korrelieren gut mit den Ergebnissen der stereophotogrammetrischen Verformungsmessungen der Struktur.
T2 - 22. Kolloquium Schallemission und 3. Anwenderseminar Zustandsüberwachung mit geführten Wellen
CY - Karlsruhe, Germany
DA - 27.03.2019
KW - Brückenmonitoring
KW - Schallemissionsanalyse
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477878
SN - 978-3-947971-00-8
VL - 169
SP - 1
EP - 5
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-47787
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Thiele, Marc
A1 - Hille, Falk
A1 - Makris, Ruben
ED - Helmerich, Rosemarie
ED - Ilki, A.
ED - Motavalli, M.
T1 - Comparison of fatigue crack detection methods for high-cyclic loaded steel structures
N2 - At present, to produce renewable energy offshore wind farms play an important role. The available space combined with the more valuable wind conditions make offshore locations very attractive for wind powered energy production. In Europe a significant number of offshore wind farms already exist, especially in the North and Baltic Sea. In future this trend will continue, and further offshore wind farms will be built. The majority of offshore wind turbines are mounted on steel foundation structures. Due to the high-cyclic loading by wind and waves fatigue stress plays a substantial role regarding structural safety.
Besides the consideration of fatigue within the design process, to monitor existing steel structures for potential fatigue cracks during their life time is a major topic and a challenge.
For the structures of the offshore wind turbines are large and partially under water effective reliable methods for the detection of fatigue cracks are required.
This contribution presents investigations on different crack detection methods applied at high-cycle fatigue tests on small-scale welded steel samples as well as on large-scale welded steel components. The tests were conducted at the BAM laboratories. For crack detection mainly three different methods were used and compared. The first method regards to the measurement of strain by conventionally strain gauges. Secondly, the crack luminescence was used as a new and effective optical method for surface monitoring. And finally, crack detection by pressure differentials of the inner and outer section of tubular steel elements was investigated. A comparison study will emphasize the advantages and disadvantages of the different methods and show which of the described methods is potentially more suitable for an application on real offshore wind structures.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.2019
KW - Fatigue
KW - Steel structures
KW - Crack detection
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489433
SP - Th.2.A.1-1
EP - Th.2.A.1-8
AN - OPUS4-48943
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Niederleithinger, Ernst
A1 - Maak, Stefan
A1 - Mielentz, Frank
A1 - Effner, Ute
A1 - Strangfeld, Christoph
A1 - Timofeev, Juri
T1 - Review of recent developments in ultrasonic echo testing of concrete
N2 - Ultrasonic methods are used in concrete investigations since decades. While being limited to transmission testing in the laboratory for a while, in-situ echo measurements for structural investigations and condition assessment have made their way into practical application in the past 20 years. However, several challenges remain. On one side, there are technical issues as limitations in depth of penetration, resolution and imaging capabilities. On the other side there are still gaps in validation, standardization and certification, which are limiting the applicability in condition/load capacity assessment.
This review reports a couple of developments which will help to overcome these issues. This includes technical developments as new devices which are easier to handle on site or giving a much deeper penetration depth (e.g. the LAUS device at BAM) as well as improvements in imaging by hardware update (e. g. air coupled ultrasound or coded signals) or new software (e. g. RTM imaging). To foster the application in real world projects we are as well working on standardization by developing new reference specimen with international partners which will ensure world-wide comparability of ultrasonic and other methods and quality assurance codes. Further, non-destructive methods are being used to update probabilistic models used for the reassessment of existing structures to support the structural engineer’s decisions.
T2 - SMAR 2019
CY - Potsdam, Germany
DA - 27.08.2019
KW - Engineered Barrier System (EBS)
KW - Ultraschall
KW - NDT
KW - Re-assessment of exiting bridges
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489686
SP - 1
EP - 6
AN - OPUS4-48968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Teng, Jun
A1 - Tang, De-Hui
A1 - Zhang, Xiao
A1 - Hu, Wei-Hua
A1 - Said, Samir
A1 - Rohrmann, Rolf G.
T1 - Automated modal analysis for tracking structural change during construction and operation phases
N2 - The automated modal analysis (AMA) technique has attracted significant interest over the last few years, because it can track variations in modal parameters and has the potential to detect structural changes. In this paper, an improved density-based spatial clustering of applications with noise (DBSCAN) is introduced to clean the abnormal poles in a stabilization diagram. Moreover, the optimal system model order is also discussed to obtain more stable poles. A numerical Simulation and a full-scale experiment of an arch bridge are carried out to validate the effectiveness of the proposed algorithm. Subsequently, the continuous dynamic monitoring system of the bridge and the proposed algorithm are implemented to track the structural changes during the construction phase. Finally, the artificial neural network (ANN) is used to remove the temperature effect on modal frequencies so that a health index can be constructed under operational conditions.
KW - Automated Modal Analysis for Tracking Structural Change during Construction and Operation Phases
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475116
UR - https://www.mdpi.com/1424-8220/19/4/927/pdf
DO - https://doi.org/10.3390/s19040927
SN - 1424-8220
VL - 19
IS - 4
SP - 927, 1
EP - 23
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-47511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ren, J.
A1 - Weigert, Florian
A1 - Weber, F.
A1 - Wang, Y.
A1 - Choudhury, S.
A1 - Xiao, J.
A1 - Lauermann, I.
A1 - Resch-Genger, Ute
A1 - Bande, A.
A1 - Petit, T.
ED - Petit, Tristan
T1 - Influence of surface chemistry on optical, chemical and electronic properties of blue luminescent carbon dots
N2 - Carbon dots have attracted much attention due to their unique optical, chemical and electronic properties enabling a wide range of applications. The properties of carbon dots can be effectively adjusted through modifying their chemical composition. However, a major challenge remains in understanding the core and surface contributions to optical and electronic transitions. Here, three blue luminescent carbon dots with carboxyl, amino and hydroxyl groups were comprehensively characterized by UV-vis absorption and emission spectroscopy, synchrotron-based X-ray spectroscopy, and infrared spectroscopy. The influence of the surface functionality on their fluorescence was probed by pH-dependent photoluminescence measurements. Moreover, the hydrogen bonding interactions between water and the surface groups of carbon dots were characterized by infrared spectroscopy. Our results show that both core and surface electronic states of blue luminescent carbon dots contribute to electronic acceptor levels while the chemical nature of the surface groups determines the hydrogen bonding behavior of the carbon dots. This comprehensive spectroscopic study demonstrates that the surface chemistry has a profound influence on the electronic configuration and surface–water interaction of carbon dots, thus affecting their photoluminescence properties.
KW - Quantum dots
KW - Spectroscopy
KW - UV Vis
KW - Fluorescence
KW - Surface chemistry
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472325
DO - https://doi.org/10.1039/c8nr08595a
SN - 2040-3372
VL - 11
IS - 4
SP - 2056
EP - 2064
PB - RSC
AN - OPUS4-47232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duffner, Eric
A1 - Mair, Georg W.
A1 - Munzke, Dorit
A1 - Szczepaniak, Mariusz
A1 - Schukar, Marcus
T1 - Lebensdauerversuche an Faserverbund-Druckbehältern überwacht mittels Schallemissionsprüfung und optischen Fasern
N2 - Kurzfassung. Die meisten Faserverbundbehälter, die in Europa für den Transport gefährlicher Stoffe oder als Speicherbehälter für Wasserstoff oder Erdgas in Fahrzeugen Verwendung finden, werden für eine nicht begrenzte Lebensdauer ausgelegt. In regelmäßigen Abständen sind für diese Druckbehälter wiederkehrende Prüfungen vorgeschrieben, die in der Regel aus visuellen Inspektionen und hydraulischen Innendruckprüfungen bestehen. Die wiederkehrenden Prüfungen sind jedoch weder geeignet, die sichere Betriebsdauer festzulegen noch den Alterungszustand der Druckbehälter zu beurteilen. Aufgrund des weiter steigenden Drucks zur Kosten- und Gewichtsreduktion von Faserverbundbehältern und der damit einhergehenden Ausnutzung der existierenden Sicherheitsmargen gewinnen Methoden zur Beurteilung des Alterungsverhaltens dieser Druckbehälter immer mehr an Bedeutung.
Vor diesem Hintergrund wurde in der BAM das Vorhaben „Alterungsverhalten von Composite-Druckgefäßen mit Carbonfaser-Compositen unter gekoppelten Beanspruchungen (COD-AGE)“ gestartet, um die Alterung von Faserverbundbehältern mittels verschiedener zerstörungsfreier Prüfverfahren zu untersuchen. Die hier vorgestellten Ergebnisse wurden an einem Typ 4 Hybridbehälter mit Kunststoffliner gewonnen, in den im Rahmen des Herstellungsprozesses optische Glasfasern in verschiedenen Schichten integriert wurden. Der Behälter wurde mittels hydraulischem Innendruck und erhöhter Umgebungstemperatur zyklisch bis zum Lebensende belastet. Zwischen den einzelnen Lastsequenzen erfolgte eine an die wiederkehrende Prüfung im Betrieb angelehnte hydraulische Druckbelastung.
Sowohl die hydraulische Alterung als auch die Druckrampen wurden mittels Schallemissionsprüfung (SEP) und verteilter faseroptischer Sensorik mit dem Ziel einer frühzeitigen Versagensvorhersage überwacht. Durch die Schallemissionsanalyse sollte untersucht werden, ob zum Lebensende hin ein signifikanter Anstieg der Schallemissionsaktivität und -intensität, unterteilt in verschiedene Lastbereiche, beobachtet werden kann. Zusätzlich zum kontinuierlichen Monitoring der Zyklierung sollten die Druckrampen separat untersucht werden, um hier Potenziale für die wiederkehrende Prüfung zu erkennen.
T2 - 22. Kolloquium Schallemission und 3. Anwenderseminar Zustandsüberwachung mit geführten Wellen
CY - Karlsruhe, Germany
DA - 27.03.2019
KW - Faserverbund
KW - Druckbehältern
KW - Lebensdauerversuche
KW - Schallemissionsprüfung
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479534
SP - 1
EP - 10
PB - DGZfP
CY - Berlin
AN - OPUS4-47953
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krautz, M.
A1 - Beyer, M.
A1 - Jäschke, C.
A1 - Schinke, L.
A1 - Waske, Anja
A1 - Seifert, J.
T1 - A Magnetocaloric Booster Unit for Energy-Efficient Air-Conditioning
N2 - A concept for the application of a magnetocaloric device in energy-efficient air conditioners is introduced. In order to evaluate this concept, a test stand has been developed equipped with a magnetic field source providing about a 1.5-T flux density change into which different Regenerator geometries can be implemented and evaluated. A processing route for the production of profiled magnetocaloric LaFeSiMn-based composite plates by tape casting is presented. The processed plates show a maximum isothermal entropy change of about 3.8 J kg−1 K−1 at a magnetic field change of 1.5 T at 285 K. The hydraulic and thermal performance of regenerator geometries that can be realized by profiled plates is assessed by calculations.
KW - Magnetocaloric effect
KW - Regenerator
KW - Air-conditioning
KW - Solid state cooling
KW - Tape casting
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480926
DO - https://doi.org/10.3390/cryst9020076
VL - 9
IS - 2
SP - 76
EP - 91
PB - MDPI
AN - OPUS4-48092
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ghafafian, Carineh
A1 - Popiela, Bartosz
A1 - Nielow, Dustin
A1 - Trappe, Volker
T1 - Restoration of structural integrity – a comparison of various repair concepts for wind turbine rotor blade shells
N2 - Localized patches are a cost- and time-effective method for repairing fiber-reinforced polymer (FRP) sandwich wind turbine rotor blade shells. To increase the understanding of their effect on the fatigue of the blades, this study examines the effect of various layup methods of localized repair patches on the structural integrity of composite sandwich structures. Manufactured with the vacuum-assisted resin infusion (VARI) process, the shell test specimens are produced as a curved structure with glass fiber reinforced polymer (GFRP) sandwiching a polyvinyl chloride (PVC) foam core. Patch repairs are then introduced with varying layup techniques, and material properties are examined with cyclic fatigue tests. The transition region between patch and parent material is studied in greater detail with finite element method (FEM) simulations, with a focus on the effect of fiber orientation mismatch. Damage onset, crack development, and eventual failure are monitored with in-situ non-destructive testing methods to develop a robust understanding of the effects of repair concepts on material stiffness and strength.
T2 - SMAR 2019 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.2019
KW - Lightweight materials
KW - Glass fiber reinforced polymers
KW - Sandwich
KW - Wind turbine blades
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-482170
SP - 1
EP - 8
PB - German Society for Non-Destructive Testing (DGZfP e.V.)
AN - OPUS4-48217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Priebe, Nsesheye Susan
A1 - Gluth, Gregor
A1 - Sturm, Patrick
A1 - Vogler, Nico
A1 - Kühne, Hans-Carsten
T1 - Comparison of calcined illitic clays (brick clays) and low-grade kaolinitic clays as supplementary cementitious materials
N2 - The use of calcined clays as supplementary cementitious materials (SCMs) has been identified as a viable option to decrease the CO2 emissions related to cement production. However, while extensive data is available about kaolinitic clays in this context, other clays such as illitic clays appear to be under-studied. Therefore, in the present study, two illitic clays were compared to two low-grade kaolinitic clays in terms of transformations in the calcination temperature range 650–900 °C, and performance of the calcined clays in blended cement pastes as measured by strength evolution, heat release, hydrated phase formation and portlandite consumption. The illitic clays required a higher calcination temperature for complete dehydroxylation of their illite than what is necessary for dehydroxylation of kaolinite. These higher calcination temperatures also led to particle sintering, significantly decreasing the specific surface area of the illitic clays, particularly for the clay with the higher Fe2O3 content. Nevertheless, while the kaolinitic clays generally exhibited the best performance as SCM, the illitic clay with lower Fe2O3 content performed similar to the kaolinitic clays when calcined at optimum temperature and applied at a moderate substitution rate. These findings demonstrate that several different clays have the potential to be used as SCM and indicate possible routes to identify suitable deposits for this purpose.
KW - Blended cement
KW - Calcined clay
KW - Brick clay
KW - Illite
KW - Kaolinite
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488195
DO - https://doi.org/10.1617/s11527-019-1393-2
SN - 1359-5997
SN - 1871-6873
N1 - Geburtsname von Priebe, Nsesheye Susan: Msinjili, N. S. - Birth name of Priebe, Nsesheye Susan: Msinjili, N. S.
VL - 52
IS - 5
SP - Article Number 94
PB - Springer Nature
AN - OPUS4-48819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schwarz, W.
A1 - Wilsch, Gerd
A1 - Pichelhöfer, A.
A1 - Ebell, Gino
A1 - Völker, Tobias
T1 - Galvanic chloride extraction by an embedded zinc anode: Ion distribution mapped by laser induced breakdown spectroscopy (LIBS)
N2 - An important aspect with regard to the service life of zinc based galvanic anodes and the durability of the corrosion protection of steel in concrete is the “galvanic chloride extraction”. Chloride ions move in the electric field generated by the current, flowing between the galvanic anode and the cathodic steel. Migration leads to an accumulation of anions, e.g. chloride ions, at the anode and depletion of chlorides near the steel rebar surface. The ion migration was studied on steel reinforced concrete specimens admixed with 3 wt.% chloride/wt. cement and galvanically protected by a surface applied embedded zinc anode (EZA). The zinc anode was embedded and glued to the concrete surface by a geo-polymer based chloride free binder. The EZA was operated over a period of 1 year and the ion distribution between anode (EZA) and cathode (steel reinforcement) was studied by laser induced breakdown spectroscopy (LIBS) after 5 months, 7 months and 12 months. The results show that chloride ions efficiently migrate in the direction of the zinc-anode and accumulate there. Chloride distribution in the EZA correlates with the distribution of zinc ions generated by the anodic dissolution of the zinc anode in the binder matrix. The microstructure of the binder matrix and its interface to the zinc-anode are studied by REM/EDX – preliminary results will be reported.
T2 - Concrete Solutions 2019
CY - Cluj Napoca, Romania
DA - 30.09.2019
KW - Galvanic corrosion
KW - Corrosion
KW - Chloride extraction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488189
DO - https://doi.org/10.1051/matecconf/201928903010
VL - 289
SP - 03010, 1
EP - 5
PB - MATEC Web of Conferences
AN - OPUS4-48818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Otto, Peter
A1 - Lorenzis, L.
A1 - Unger, Jörg F.
T1 - Explicit dynamics in impact simulation using a NURBS contact interface
N2 - In this paper, the impact problem and the subsequent wave propagation are considered. For the contact discretization an intermediate NURBS layer is added between the contacting finite element bodies, which allows a smooth contact formulation and efficient element‐based integration. The impact event is ill‐posed and requires a regularization to avoid propagating stress oscillations. A nonlinear mesh dependent penalty regularization is used, where the stiffness of the penalty regularization increases upon mesh refinement. Explicit time integration methods are well suited for wave propagation problems, but are efficient only for diagonal mass matrices. Using a spectral element discretization and the coupled FE‐NURBS approach the bulk part of the mass matrix is diagonal.
KW - Impact simulation
KW - Explicit dynamics
KW - Isogeometric analysis
KW - Spectral elements
KW - Mortar method
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494947
DO - https://doi.org/10.1002/nme.6264
SP - 1
EP - 21
PB - Wiley Online Libary
AN - OPUS4-49494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heckel, Thomas
A1 - Wack, Y.
A1 - Mook, G.
T1 - Simulation von mechanisierten Eisenbahnschienenprüfungen mit Ultraschall
N2 - Bei der mechanisierten Prüfung von verlegten Eisenbahnschienen mit Schienenprüfzügen werden große Prüfdatenmengen mit einer komplexen Prüfkopfanordnung in kurzer Zeit bei hohen Prüfgeschwindigkeiten aufgenommen. Der Typ und der Zustand des Gleises kann während der Prüfung in schnellem Wechsel streckenabhängig variieren, z.B. unterschiedliche Schienentypen oder Abnutzung sowie beim Durchfahren von Weichenstraßen. Der logistische Aufwand diese Prüfung insgesamt durchzuführen ist dabei sehr hoch und eine Wiederholung der Prüfung in einem kurzen Zeitintervall nicht möglich.
Es werden während der Prüfdatenaufnahme bereits Datenreduktionsverfahren, Rekonstruktionsverfahren und Online-Parametervariationen eingesetzt, um die Ergebnisdaten zum einen in Ihrer Menge zu begrenzen zum anderen auf die lokalen Geometrie- und Zustandsänderungen des Prüfobjektes Schiene zu reagieren.
Im Regelwerk EN 16729-1 „Zerstörungsfreie Prüfung an Schienen im Gleis -Teil 1: Anforderungen an Ultraschallprüfungen und Bewertungsgrundlagen“ werden Bezugsreflektoren definiert, um die Leistung automatisierter Ultraschallsysteme für die Schienenprüfung zu verifizieren.
Um die Einflüsse der komplexen Randbedingungen der mechanisierten Schienenprüfung auf das Prüfergebnis evaluieren zu können, wurde ein Softwarewerkzeug erarbeitet, mit dem eine Prüffahrt auf einer Schiene simuliert werden kann. Basierend auf der Datenaufnahme mit dem Glassy-Rail-Diagramm können alle relevanten Prüfparameter und Artefakte in Schienen sowie Störeinflüsse bei der Simulation berücksichtigt werden.
T2 - DGZfP DACH Tagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Schiene
KW - Zerstörungsfreie Prüfung
KW - Ultraschall
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496749
VL - 2019
SP - 1
EP - 8
AN - OPUS4-49674
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beilken, D.
A1 - Rühe, S.
A1 - Heckel, Thomas
A1 - Casperson, Ralf
T1 - Aktuelle Entwicklungen der Wirbelstrom- und Ultraschallprüfung an verlegten Eisenbahnschienen
N2 - Die kombinierte Schienenprüfung mit Wirbelstrom und Ultraschall ermöglicht eine ganzheitliche Detektion von Inhomogenitäten im Kopf und Steg der Schiene und gewährleistet das Auffinden sowohl von Volumen-als auch Oberflächeneffekten wie z. B. Head Checks. Für die verbesserte Detektion von Rollkontaktermüdung (rolling contact fatique, RCF) und den daraus resultierenden Schienenfehlern (Head-Checks, Squats, Riffel, …) wurde für die Wirbelstromprüfung der Prüfbereich auf die gesamte Rollkontaktfläche erweitert. Der Fokus liegt im Neudesign der Wirbelstrom-Prüfvorrichtung und der damit verbundenen normgerechten Auslegung der Konstruktion für die fahrzeugspezifischen Gegebenheiten. Ferner wurde die Anwendersoftware des kombinierten Prüfsystems vereinheitlicht. Um die wirtschaftliche Effektivität unsere Prüftechnik zu steigern, wird die Multiplex-Gerätetechnologie in die automatisierte Schienenprüfung eingeführt. Damit wird der freizuhaltende Einbauraum innerhalb der Fahrzeuge sowie Kabelwege deutlich reduziert. Durch den Übergang zu der Multiplextechnologie wurde weiterhin die Stromaufnahme um mehr als 50% reduziert.
T2 - DGZfP DACH Tagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Schienenprüfung
KW - Zerstörungsfreie Prüfung
KW - Ultraschall
KW - Wirbelstrom
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496775
VL - 2019
SP - 1
EP - 10
AN - OPUS4-49677
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wosniok, Aleksander
A1 - Skoczowsky, Danilo
A1 - Schukar, Marcus
A1 - Pötzsch, Sina
A1 - Pötschke, Samuel
A1 - Krüger, Simone
T1 - Fiber optic sensors for high-temperature measurements on composite tanks in fire
N2 - For the purpose of increasing payload and reduce freight cost, lightweight composite tank containers used for Transportation have been progressively developed during the last years. Compared to conventionally produced cylindrical steel tanks, the fiber-reinforced solutions allow greater flexibility in the tank design. Despite a number of further material-related benefits of fiber-reinforced composites as non-conductive and non-magnetic behavior as well as corrosion resistance and high strength, the optimization of their thermal degradation properties during combustion is still a challenge. To improve the fire performance of lightweight composite containers, special intumescent fire protection coatings can be applied onto the outside tank surface. This paper presents fire tests on glass-fiber-reinforced plastic transport tanks with complex geometries sheltered with different surface-applied fire protection systems. To evaluate the fire resistance of the tank structures, a fiber optic monitoring system was developed. This system is based on distributed temperature measurements using high-Resolution optical backscatter reflectometry and pointwise reference measurements using fiber Bragg gratings. Thereby, all the fiber optic sensors were directly integrated in the composite layer structure of the tanks. The focus of the presented work is on the demonstration of capability of fiber optic monitoring system in such high-temperature application. Moreover, the fiber optic measurements provide new insights into the efficiency of intumescent coating applied for fire protection of fiber-reinforced plastic transport tanks.
KW - Fire resistance
KW - Composite material
KW - Glass-fiber-reinforced plastic transport tank
KW - Distributed fiber optic sensing
KW - Optical backscatter reflectometry
KW - Fiber optic sensor
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481972
DO - https://doi.org/10.1007/s13349-019-00338-7
SN - 2190-5452
SN - 2190-5479
SP - 1
EP - 8
PB - Springer Nature
AN - OPUS4-48197
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hussels, Maria-Teresa
A1 - Chruscicki, Sebastian
A1 - Arndt, Detlef
A1 - Scheider, Swen
A1 - Prager, Jens
A1 - Homann, Tobias
A1 - Habib, Abdel Karim
T1 - Localization of transient events threatening pipeline integrity by fiber-optic distributed acoustic sensing
N2 - Pipe integrity is a central concern regarding technical safety, availability, and environmental compliance of industrial plants and pipelines. A condition monitoring system that detects and localizes threats in pipes prior to occurrence of actual structural failure, e.g., leakages, especially needs to target transient events such as impacts on the pipe wall or pressure waves travelling through the medium. In the present work, it is shown that fiber-optic distributed acoustic sensing (DAS) in conjunction with a suitable application geometry of the optical fiber sensor allows to track propagating acoustic waves in the pipeline wall on a fast time-scale. Therefore, short impacts on the pipe may be localized with high fidelity. Moreover, different acoustic modes are identified, and their respective group velocities are in good agreement with theoretical predications. In another set of experiments modeling realistic damage scenarios, we demonstrate that pressure waves following explosions of different gas mixtures in pipes can be observed. Velocities are verified by local piezoelectric pressure transducers. Due to the fully distributed nature of the fiber-optic sensing system, it is possible to record accelerated motions in detail. Therefore, in addition to detection and localization of threatening events for infrastructure monitoring, DAS may provide a powerful tool to study the development of gas explosions in pipes, e.g., investigation of deflagration-to-detonation-transitions (DDT).
KW - Distributed acoustic sensing (DAS)
KW - Distributed vibrations sensing (DVS)
KW - Fiber-optic sensing
KW - Condition monitoring
KW - Pipeline integrity
KW - Gas explosion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488555
DO - https://doi.org/10.3390/s19153322
SN - 1424-8220
VL - 19
IS - 15
SP - 3322, 1
EP - 20
PB - MDPI
CY - Basel, CH
AN - OPUS4-48855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Provis, J. L.
A1 - Arbi, K.
A1 - Bernal, S. A.
A1 - Bondar, D.
A1 - Buchwald, A.
A1 - Castel, A.
A1 - Chithiraputhiran, S.
A1 - Cyr, M.
A1 - Dehghan, A.
A1 - Dombrowski-Daube, K.
A1 - Dubey, A.
A1 - Ducman, V.
A1 - Gluth, Gregor
A1 - Nanukuttan, S.
A1 - Peterson, K.
A1 - Puertas, F.
A1 - van Riessen, A.
A1 - Torres-Carrasco, M.
A1 - Ye, G.
A1 - Zuo, Y.
T1 - RILEM TC 247-DTA round robin test: mix design and reproducibility of compressive strength of alkali-activated concretes
N2 - The aim of RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ is to identify and validate methodologies for testing the durability of alkali-activated concretes. To underpin the durability testing work of this committee, five alkali-activated concrete mixes were developed based on blast furnace slag, fly ash, and flash-calcined metakaolin. The concretes were designed with different intended performance levels, aiming to assess the capability of test methods to discriminate between concretes on this basis. A total of fifteen laboratories worldwide participated in this round robin test programme, where all concretes were produced with the same mix designs, from single-source aluminosilicate precursors and locally available aggregates. This paper reports the mix designs tested, and the compressive strength results obtained, including critical insight into reasons for the observed variability in strength within and between laboratories.
KW - Alkali-activated materials
KW - Alkali-activated slag
KW - Compressive strength
KW - Concrete
KW - Mix-design
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489131
DO - https://doi.org/10.1617/s11527-019-1396-z
SN - 1359-5997
SN - 1871-6873
VL - 52
IS - 5
SP - Article Number 99
PB - Springer Nature
AN - OPUS4-48913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoevelmann, J.
A1 - Stawski, T. M.
A1 - Besselink, R.
A1 - Freeman, H. M.
A1 - Dietmann, K. M.
A1 - Mayanna, S.
A1 - Pauw, Brian Richard
A1 - Benning, L. G.
T1 - A template-free and low temperature method for the synthesis of mesoporous magnesium phosphate with uniform pore structure and high surface area
N2 - Mesoporous phosphates are a group of nanostructured materials with promising applications, particularly in biomedicine and catalysis. However, their controlled synthesis via conventional template-based routes presents a number of challenges and limitations. Here, we show how to synthesize a mesoporous Magnesium phosphate with a high surface area and a well-defined pore structure through thermal decomposition of a crystalline struvite (MgNH4PO4·6H2O) precursor. In a first step, struvite crystals with various morphologies and sizes, ranging from a few micrometers to several millimeters, had been synthesized from supersaturated aqueous solutions (saturation index (SI) between 0.5 and 4) at ambient pressure and temperature conditions. Afterwards, the crystals were thermally treated at 70–250 °C leading to the release of structurally bound water (H2O) and ammonia (NH3). By combining thermogravimetric analyses (TGA), scanning and transmission electron microscopy (SEM, TEM), N2 sorption analyses and small- and wide-angle X-ray scattering (SAXS/WAXS) we show that this decomposition process results in a pseudomorphic transformation of the original struvite into an amorphous Mg-phosphate. Of particular importance is the fact that the final material is characterized by a very uniform mesoporous structure with 2–5 nm wide pore channels, a large specific surface area of up to 300 m2 g−1 and a total pore volume of up to 0.28 cm3 g−1. Our struvite decomposition method is well controllable and reproducible and can be easily extended to the synthesis of other mesoporous phosphates. In addition, the so produced mesoporous material is a prime candidate for use in biomedical applications considering that Magnesium phosphate is a widely used, non-toxic substance that has already shown excellent biocompatibility and biodegradability.
KW - Struvite
KW - SAXS
KW - Scattering
KW - Nanoporous
KW - Geology
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477130
DO - https://doi.org/10.1039/c8nr09205b
VL - 11
IS - 14
SP - 6939
EP - 6951
PB - Royal Society of Chemistry
AN - OPUS4-47713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Descalzo, Ana B.
A1 - Ashokkumar, Pichandi
A1 - Shen, Z.
A1 - Rurack, Knut
T1 - On the Aggregation Behaviour and Spectroscopic Properties of Alkylated and Annelated BoronDipyrromethene (BODIPY) Dyes in Aqueous Solution
N2 - The tendency of boron-dipyrromethene (BODIPY) dyes to associate in water is well known, and usually a cause for inferior fluorescence properties. Synthetic efforts to chemically improve BODIPYs’ water solubility and minimize this problem have been numerous in the past. However, a deeper understanding of the phenomena responsible for fluorescence quenching is still required. Commonly, the spectroscopic behaviour in aqueous media has been attributed to aggregate or excimer formation, with such works often centring on a single BODIPY family. Herein, we provide an integrating discussion including very diverse types of BODIPY dyes. Our studies revealed that even subtle structural changes can distinctly affect the association behaviour of the fluorophores in water, involving different photophysical processes. The palette of behaviour found ranges from unperturbed emission, to the formation of H or J aggregates and excimers, to the involvement of tightly bound, preformed excimers. These results are a first step to a more generalized understanding of spectroscopic properties vs. structure, facilitating future molecular design of BODIPYs, especially as probes for biological applications.
KW - Aggregates
KW - BODIPY
KW - Excimers
KW - Fluorescence
KW - Photophysics
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497771
DO - https://doi.org/10.1002/cptc.201900235
SN - 2367-0932
VL - 4
IS - 2
SP - 120
EP - 131
PB - WILEY-VCH
CY - Weinheim
AN - OPUS4-49777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, H.
A1 - Song, W.
A1 - Gröninger, Delia
A1 - Zhang, L.
A1 - Lu, Y.
A1 - Chan, K. S.
A1 - Zhou, Z.
A1 - Rurack, Knut
A1 - Shen, Z.
T1 - Real-time monitoring of newly acidified organelles during autophagy enabled by reaction-based BODIPY dyes
N2 - Real-time monitoring of newly acidified organelles during autophagy in living cells is highly desirable for a better understanding of intracellular degradative processes. Herein, we describe a reaction-based boron dipyrromethene (BODIPY) dye containing strongly electron-withdrawing diethyl 2-cyanoacrylate groups at the α-positions. The probe exhibits intense red fluorescence in acidic organelles or the acidified cytosol while negligible fluorescence in other regions of the cell. The underlying mechanism is a nucleophilic reaction at the central meso-carbon of the indacene core, resulting in the loss of π-conjugation entailed by dramatic spectroscopic changes of more than 200 nm between its colorless, non-fluorescent leuco-BODIPY form and its red and brightly emitting form. The reversible transformation between red fluorescent BODIPY and leuco-BODIPY along with negligible cytotoxicity qualifies such dyes for rapid and direct intracellular lysosome imaging and cytosolic acidosis detection simultaneously without any washing step, enabling the real-time monitoring of newly acidified organelles during autophagy.
KW - Autophagy
KW - BODIPY
KW - Fluorescence
KW - Lysosome
KW - Real-time imaging
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498358
UR - https://www.nature.com/articles/s42003-019-0682-1
DO - https://doi.org/10.1038/s42003-019-0682-1
SN - 23993642
VL - 2
SP - 442
PB - Nature Research
CY - London
AN - OPUS4-49835
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Büchele, Dominique
A1 - Chao, Madlen
A1 - Ostermann, Markus
A1 - Leenen, M.
A1 - Bald, Ilko
T1 - Multivariate chemometrics as a key tool for prediction of K and Fe in a diverse German agricultural soil-set using EDXRF
N2 - Within the framework of precision agriculture, the determination of various soil properties is moving into focus, especially the demand for sensors suitable for in-situ measurements. Energy-dispersive X-ray fluorescence (EDXRF) can be a powerful tool for this purpose. In this study a huge diverse soil set (n = 598) from 12 different study sites in Germany was analysed with EDXRF. First, a principal component analysis (PCA) was performed to identify possible similarities among the sample set.
Clustering was observed within the four texture classes clay, loam, silt and sand, as clay samples contain high and sandy soils low iron mass fractions. Furthermore, the potential of uni- and multivariate data evaluation with partial least squares regression (PLSR) was assessed for accurate Determination of nutrients in German agricultural samples using two calibration sample sets. Potassium and iron were chosen for testing the performance of both models. Prediction of these nutrients in 598 German soil samples with EDXRF was more accurate using PLSR which is confirmed by a better overall averaged deviation and PLSR should therefore be preferred.
KW - XRF
KW - Chemometrics
KW - Soil
KW - Agriculture
KW - Multivariate
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498671
DO - https://doi.org/10.1038/s41598-019-53426-5
VL - 9
SP - 17588
PB - Nature
AN - OPUS4-49867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Koch, Claudia
ED - Mangelsdorf, Axel
ED - Weiler, Petra
T1 - Normung für neue Technologien am Beispiel Additiver Fertigung
N2 - Der Beitrag beleuchtet die Normung für neue Technologien am Beispiel Additiver Fertigung im Hinblick auf ihren Beitrag zur Diffusion in den Markt
KW - Additive Fertigung
KW - Innovation
KW - Normen
KW - Standards
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473812
UR - https://www.degruyter.com/view/books/9783110629057/9783110629057-003/9783110629057-003.xml
SN - 978-3-11062-905-7
DO - https://doi.org/10.1515/9783110629057
VL - 2019
SP - 18
EP - 36
PB - De Gruyter
CY - Berlin, Boston
ET - 1
AN - OPUS4-47381
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwibbert, Karin
A1 - Menzel, F.
A1 - Epperlein, N.
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - Bacterial adhesion on femtosecond laser-modified polyethylene
N2 - In this study, femtosecond laser-induced sub-micrometer structures are generated to modify polyethylene (PE) surface topographies. These surfaces were subjected to bacterial colonization studies with Escherichia coli and Staphylococcus aureus as test strains. The results reveal that the nanostructures do not influence S. aureus coverage, while the adhesion of E. coli is reduced.
KW - Bacterial adhesion
KW - Laser-modified surface
KW - Polyethylene
KW - Laser-induced nanostructures
KW - Biofilm
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492280
DO - https://doi.org/10.3390/ma12193107
VL - 12
IS - 19
SP - 3107
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-49228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gharaati, S.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Weigert, Florian
A1 - Resch-Genger, Ute
A1 - Heinze, K.
T1 - Triplet–Triplet Annihilation Upconversion in a MOF with AcceptorFilled Channels
N2 - In summary, we report a highly modular solid TTA-UC system comprising of a crystalline, thermally stable PCN222(Pd) MOF with CA-coated MOF channels and with a DPA annihilator embedded in a solution-like environment in the MOF channels. This solid material displays blue upconverted delayed emission with a luminescence lifetime of 373 us, a threshold value of 329 mW*cm-2 and a triplet–triplet energy transfer efficiency of 82%. This optical application adds another facet to the versatile chemistry of PCN-222 MOFs. The design concept is also applicable to other TTA-UC pairs and enables tuning of the UCL color, for example, by replacing DPA with other dyes as exemplarily shown for 2,5,8,11-tetra-tert-butyl-perylene, that yields UCL at 450 nm. Current work aims to reduce the oxygen sensitivity and to increase the retention of the trapped annihilators in organic environments, for example, by tuning the chain length of the carboxylic acid and by coating the MOF surface. In addition, the TTA-UC efficiency will be further enhanced by reducing the reabsorption of the UC emission caused by Pd(TCPP) and by optimizing the sensitizer/annihilator interface.
KW - Porphyrin
KW - Method
KW - MOF
KW - Fluorescence
KW - Dye
KW - Sensor
KW - Oxygen sensitive
KW - Single molecule
KW - DPA
KW - Lifetime
KW - Upconverstion
KW - Quantum yield
KW - Triplet-triplet annihilation
KW - Sensitization
KW - Energy transfer
KW - NMR
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500580
DO - https://doi.org/10.1002/chem.201904945
VL - 26
IS - 5
SP - 1003
EP - 1007
PB - Wiley-VCH Verlag
CY - Weinheim
AN - OPUS4-50058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kembuan, C.
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Resch-Genger, Ute
A1 - Graf, C.
T1 - Coating of upconversion nanoparticles with silica nanoshells of 5–250 nm thickness
N2 - A concept for the growth of silica shells with a thickness of 5–250 nm onto oleate-coated NaYF4:Yb3+/Er3+ upconversion nanoparticles (UCNP) is presented. The concept enables the precise adjustment of shell thicknesses for the preparation of thick-shelled nanoparticles for applications in plasmonics and sensing. First, an initial 5–11 nm thick shell is grown onto the UCNPs in a reverse microemulsion. This is followed by a stepwise growth of these particles without a purification step, where in each step equal volumes of tetraethyl orthosilicate and ammonia water are added, while the volumes of cyclohexane and the surfactant Igepal® CO-520 are increased so that the ammonia water and surfactant concentrations remain constant. Hence, the number of micelles stays constant, and their size is increased to accommodate the growing core–shell particles. Consequently, the formation of core-free silica particles is suppressed. When the negative zeta potential of the particles, which continuously decreased during the stepwise growth, falls below −40 mV, the particles can be dispersed in an ammoniacal ethanol solution and grown further by the continuous addition of tetraethyl orthosilicate to a diameter larger than 500 nm. Due to the high colloidal stability, a coalescence of the particles can be suppressed, and single-core particles are obtained. This strategy can be easily transferred to other nanomaterials for the design of plasmonic nanoconstructs and sensor systems.
KW - Reverse microemulsion
KW - Silica coating
KW - Stepwise growth
KW - Thick shells
KW - Upconversion nanoparticles
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502769
DO - https://doi.org/10.3762/bjnano.10.231
SN - 2190-4286
VL - 10
SP - 2410
EP - 2421
PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften
CY - Frankfurt, M.
AN - OPUS4-50276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Gröber, A.
A1 - Simkin, Roman
A1 - Kranzmann, Axel
T1 - Influence of Surface Quality on the Corrosion and Corrosion Fatigue Behavior of High Alloyed Steels Exposed to Different Saline Aquifer Water Environment
N2 - Coupons of X5CrNiCuNb16-4 with different surface roughness that may be utilized as injection pipe with 16% Chromium and 0.05% Carbon (1.4542, AISI 630) were exposed for 3000 h to CO2-saturated saline aquifer water simulating the conditions in the Northern German Basin at ambient pressure and 60 °C. Additionally, corrosion fatigue experiments (ambient pressure, technically clean CO2, saline aquifer water of Stuttgart Aquifer) were performed using specimen of X46Cr13 (1.4043, AISI 420C) with regard to the influence of the roughness of technical surfaces on the number of cycles to failure at different stress amplitudes. Specimen of Duplex stainless steel X2CrNiMoN22-3-2 (1.4462) for corrosion fatigue experiments were provided with technical surfaces after machining as well as polished surfaces. Results were obtained at load amplitudes ranging from 175 MPa to 325 MPa in the geothermal brine of the Northern German Basin at 98 °C. The main precipitation phases on the surface as well as within pits reveal carbonates or hydroxides such as siderite (FeCO3) and ferrous hydroxide goethite (FeOOH) independent of the original surface roughness. Corrosion rates for polished and technical surfaces were below 0.005 mm/year compared to corrosion rates of 0.035 mm/year after shot peening. Specimen with technical surfaces tested at high stress amplitudes (>275 MPa) lasted longer (cycles to failure: P50% at Sa 300 MPa=5x105) than specimen with polished surfaces (cycles to failure: P50% at Sa 300 MPa=1.5x105). This behavior is emphasized by the slope coefficient (technical surfaces k = 19.006, polished surfaces k=8.78) meaning earlier failure for polished at high stress amplitude Sa. Although rather low scatter ranges (technical surface: TN=1:1.35, polished surface: TN=1.1.95) indicate no change in failure mechanism it may be assumed that at low stress pitting is the initiating crack growth process whereas at high stress amplitudes the formation of micro cracks is reason for crack propagation and failure.
KW - High Alloyed Steel
KW - Pitting
KW - Surface
KW - Roughness
KW - Corrosion Fatigue
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503772
DO - https://doi.org/10.20319/mijst.2019.51.115137
SN - 2454-5880
VL - 5
IS - 1
SP - 115
EP - 137
PB - Global Research and Development Services Publishing
CY - Rajasthan, India
AN - OPUS4-50377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfennig, A.
A1 - Kranzmann, Axel
T1 - Corrosion and Fatigue of Heat Treated Martensitic Stainless Steel 1.4542 used for Geothermal Applications
N2 - During capture and storage technology (CCS) as well as in geothermal energy production Steels need to withstand the corrosive environment such as: heat, pressure, salinity of the aquifer and CO2-partial pressure. 1.4542 shows unusual corrosion phenomena, but is still sufficiently resistant in corrosive environments. To better understand its behaviour differently heat treated coupons of 1.4542 and for comparison X20Cr13 and X46Cr13 were kept in the artificial brine of the Northern German Basin at T=60 °C. Ambient pressure as well as p=100 bar for 700 h - 8000 h in water saturated supercritical CO2 and CO2-saturated synthetic aquifer Environment was applied. Fatigue tests were performed via push-pull tests with a series of 30 specimens from 150 MPa to 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ~ 30 Hz). FeCO3 and FeOOH are corrosion products also after dynamic corrosion tests. Martensitic microstructure offers good corrosion resistance in geothermal environment. The S-N-curve showing no typical fatigue strength and very steep slopes of possible fatigue strength for finite life. Possible influencing artefacts, such as Al-inclusions could not be correlated to early rupture despite specimens containing inclusions at the fracture surface and cross section reached lower number of cycles. Applied potential proofed to enhance fatigue life tremendously.
KW - High Alloyed Steel
KW - Pitting
KW - Corrosion Fatigue
KW - Corrosion
KW - Endurance Limit
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503765
DO - https://doi.org/10.20319/mijst.2019.51.138158
SN - 2454-5880
VL - 5
IS - 1
SP - 138
EP - 158
PB - Global Research and Development Services Publishing
CY - Rajasthan, India
AN - OPUS4-50376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Knigge, Xenia
A1 - Ciornii, Dmitri
A1 - Reed, B.P.
A1 - Pollard, A.J.
A1 - Clifford, C.A.
A1 - Howe, T.
A1 - Vyas, N.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - Influence of the Morphology on the Functionalization of Graphene Nanoplatelets Analyzed by Comparative Photoelectron Spectroscopy with Soft and Hard X-Rays
N2 - Since its isolation, graphene has received growing attention from academia and industry due to its unique properties. However, the “what is my material” barrier hinders further commercialization. X-ray photoelectron spectroscopy (XPS) is considered as a method of choice for the determination of the elemental and chemical composition. In this work the influence of the morphology of graphene particles on the XPS results is studied and investigated as a function of X-ray energy, using conventional XPS with Al K𝜶 radiation and hard X-ray photoemission spectroscopy (HAXPES) using Cr K𝜶 radiation. Thereby, the information depth is varied between 10 and 30 nm. For this purpose, two commercial powders containing graphene nanoplatelets with lateral dimensions of either ≈100 nm or in the micrometer range are compared. These larger ones exist as stack of graphene layers which is inspected with scanning electron microscopy. Both kinds of particles are then functionalized with either oxygen or fluorine. The size of the graphene particles is found to influence the degree of functionalization. Only the combination of XPS and HAXPES allows to detect the functionalization at the outermost surface of the particles or even of the stacks and to provide new insights into the functionalization process.
KW - Functionalized graphene
KW - Hard-energy X-ray photoelectron spectroscopy
KW - X-ray photoelectron spectroscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578860
DO - https://doi.org/10.1002/admi.202300116
SN - 2196-7350
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-57886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Terborg, R.
A1 - Kim, K. J.
A1 - Hodoroaba, Vasile-Dan
T1 - Elemental composition and thickness determination of thin films by electron probe microanalysis
N2 - Electron probe microanalysis (EPMA) applies to solid samples of homogenous (bulk) chemical composition and can usually not be applied to structures which are inhomogeneous in the micrometer range such as thin film systems down to a few nm. However, in combination with the established thin film software Stratagem, the thickness as well as the elemental composition of thin films on a substrate can be determined. This has been recently successfully demonstrated for Fe-Ni on Si and Si-Ge on Al2O3 thin film systems. For both systems five samples of different elemental composition and a reference were produced and characterised by inductively coupled plasma mass spectrometry (ICP-MS), Rutherford backscattering (RBS), and transmission electron microscopy (TEM) as reference values. Last year, a new and open-source thin film evaluation programme called BadgerFilm has been released. It can also be used to determine thin film composition and thickness from intensity ratios of the unknown sample and standards (k-ratios). In this contribution, we reevaluated the data acquired for the Fe-Ni and Si-Ge systems using the BadgerFilm software package and compared the obtained elemental compositions and thickness values with the results of the Stratagem software and the reference methods. The conclusion is that the BadgerFilm software shows good agreement with the elemental composition and thickness calculated by Stratagem (mostly <2% for both composition and thickness) and with the reference values for two representative thin film systems (<1%–2% for composition and <10%–20% for thickness).
KW - Elemental composition
KW - EPMA
KW - Film thickness
KW - Thin films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576368
DO - https://doi.org/10.1002/sia.7183
SN - 0142-2421
VL - 55
SP - 496
EP - 500
PB - Wiley
AN - OPUS4-57636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Bartczack, Dorota
A1 - Taché, Olivier
A1 - Hodoroaba, Vasile-Dan
T1 - Report on the homogeneity assessment of bimodal gold materials (nPSize1 and nPSize2) and particle number concentration by frequency method
N2 - The main objective was to assess homogeneity of two bimodal gold materials, namely nPsize1 and nPSize2, containing approximately 1:1 and 10:1 particle number-based ratio of ~30nm and ~60nm particles. Particle number-based concentration within the two size fractions was determined with spICP-MS using the particle frequency method of calibration.
KW - Nanoparticles
KW - Homogeneity
KW - Particle number concentration
KW - Gold
KW - nPSize
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595451
DO - https://doi.org/10.5281/zenodo.10654245
SP - 1
EP - 5
PB - Zenodo
CY - Geneva
AN - OPUS4-59545
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Reliable physico–chemical characterisation of graphene-related and other 2D materials: present and future
N2 - In the path of commercialisation of graphene-related and other 2D materials the consolidation has begun. In this phase, it is important to build trust between the individual partners in the product value chain. This requires trustworthy statements based on reliable and reproducible material characterisation. The first steps have been taken to measure graphene and other related 2D materials (GR2Ms) under well-defined conditions. Measurands and protocols for key methods were made available for this purpose. But there are still some challenges to overcome such as (i) reference materials, (ii) reference data, (iii) reproducibility throughout the workflow, (iv) credible structure-activity relationships, bringing the standards to (v) the factory floor and to (vi) real-word products. In addition, 2D materials beyond graphene should also be considered exploiting the knowledge gained from the characterisation of GR2M.
KW - 2D Materials
KW - Commercialisation
KW - Standardisation
KW - Trust
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638122
DO - https://doi.org/10.1088/2053-1583/aded9d
SN - 2053-1583
VL - 12
IS - 4
SP - 1
EP - 8
PB - IOP Publishing
AN - OPUS4-63812
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, M. E.
A1 - Vickery, W. M.
A1 - Swift-Ramirez, W.
A1 - Arnold, A. M.
A1 - Orlando, J. D.
A1 - Schmidt, S. J.
A1 - Liu, Y.
A1 - Er, Jasmin
A1 - Schusterbauer, Robert
A1 - Ahmed, R.
A1 - Nickl, Philip
A1 - Radnik, Jörg
A1 - Donskyi, Ievgen
A1 - Sydlik, S. A.
T1 - The Mitsunobu reaction for the gentle covalent attachment of biomolecules to graphene oxide
N2 - Graphene oxide (GO) has emerged as a promising biomaterial as it is easily and cheaply synthesized, strong, cytocompatible, osteoinductive, and has a well-characterized aqueous degradation pathway. It is also a great substrate for functionalization with biomolecules such as proteins, peptides, and small molecules that can enhance or add bioactivity. Covalent chemical linkages as opposed to typical noncovalent association methods are preferable so that the biomolecules do not quickly diffuse away or face replacement by other proteins, which is critical in long time scale applications like bone regeneration. However, covalent chemistry tends to carry a drawback of harsh reaction conditions that can damage the structure, conformation, and therefore function of a delicate biomolecule like a protein. Here, the Mitsunobu reaction is introduced as a novel method of covalently attaching proteins to graphene oxide. It features gentle reaction conditions and has the added benefit of utilizing the plentiful basal plane alcohol functionalities on graphene oxide, allowing for high yield protein functionalization. The amino acid Glycine (G), the protein bovine serum albumin (BSA), and the small molecule SVAK-12 are utilized to create the three Mitsunobu Graphene (MG) materials G-MG, BSA-MG, and SVAK-MG that demonstrate the wide applicability of this functionalization method.
KW - Graphene oxide
KW - Mitsunobu reaction
KW - Covalent attachment
KW - Bovine serum albumin
KW - Macrophage polarization
KW - Osteogenesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630483
DO - https://doi.org/10.1016/j.carbon.2025.120221
VL - 238
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-63048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - XPS–SEM/EDS Tandem Analysis for the Elemental Composition of Functionalized Graphene Nanoplatelets
N2 - Over the past decade, energy-dispersive X-ray spectrometry (EDS) with scanning electron microscopy (SEM) has advanced to enable the accurate analysis of light elements such as C, N, or O. For this reason, EDS is becoming increasingly interesting as an analytical method for the elemental analysis of functionalized graphene and could be an attractive alternative to Xray photoelectron spectroscopy (XPS), which is considered the most important method for elemental analysis. In this study, comparative XPS and EDS investigations under different excitation conditions are carried out on commercially available powders containing graphene particles with different morphologies. The slightly different XPS/HAXPES and EDS results can be explained by the different information depths of the methods and the functionalization of the particle surfaces. For the material with smaller graphene particles and higher O/C ratios, all methods reported a lower O/C ratio in pellets compared with the unpressed powder samples. This clearly shows that sample preparation has a significant influence on the quantification results, especially for such a type of morphology. Overall, the study demonstrates that EDS is a reliable and fast alternative to XPS for the elemental quantification of functionalized graphene particles, provided that differences in the information depth are taken into account. Particle morphology can be examined in parallel with quantitative element analysis, since EDS spectrometers are typically coupled with SEM, which are available in a huge number of analytical laboratories.
KW - Graphene oxide
KW - SEM/EDS
KW - XPS/HAXPES
KW - Elemental composition
KW - Functionalization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647294
DO - https://doi.org/10.1021/acsomega.5c07830
SN - 2470-1343
SP - 1
EP - 7
PB - American Chemical Society (ACS)
AN - OPUS4-64729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Dang, T. T. H.
A1 - Gatla, S.
A1 - Raghuwanshi, V. S.
A1 - Tatchev, D.
A1 - Hoell, A.
T1 - Identifying the location of Cu ions in nanostructured SAPO-5 molecular sieves and its impact on the redox properties
N2 - Combining X-ray Absorption Fine Spectroscopy (XAFS) with Anomalous Small-Angle X-ray Scattering (ASAXS) determines the location of Cu2+ ions in silicoaluminophosphate (SAPO-5) frameworks prepared by hydrothermal crystallization or impregnation. As expected, for the hydrothermally prepared sample, incorporation in the SAPO-5 framework was observed. For the first time preferential location of Cu2+ ions at the inner and outer surfaces of the framework is determined. Temperature-Programmed Reduction (TPR) and X-ray Photoelectron Spectroscopy (XPS) investigations demonstrated that such Cu2+ is stable in an argon (Ar) atmosphere up to 550 °C and can only be reduced under a hydrogen atmosphere. In contrast, Cu2+ deposited by impregnation on the pure SAPO-5 framework can be easily reduced to Cu+ in an Ar atmosphere. At lower Cu amounts, mononuclear tetrahedrally coordinated Cu species were formed which are relatively stable in the monovalent form. In contrast, at higher Cu amounts, CuO particles were found which change easily between the mono- and bivalent species.
KW - Nanostructured material
KW - Molecular sieves
KW - X-ray absorption Fine Spectroscopy
KW - Anomalous Small Angle X-ray Scattering
KW - X-ray Photoelectron Spectroscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474793
DO - https://doi.org/10.1039/c8ra10417d
SN - 2046-2069
VL - 9
IS - 12
SP - 6429
EP - 6437
PB - RSC
AN - OPUS4-47479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lisec, Jan
A1 - Jaeger, Carsten
A1 - Rashid, R.
A1 - Munir, R.
A1 - Zaidi, N.
T1 - Cancer cell lipid class homeostasis is altered under nutrient-deprivation but stable under hypoxia
N2 - Background: Cancer cells modify the balance between fatty acid (FA) synthesis and uptake under metabolic stress, induced by oxygen/nutrient deprivation. These modifications were shown to alter the levels of individual triglyceride (TG) or phospholipid sub-species. To attain a holistic overview of the lipidomic profiles of cancer cells under stress we performed a broad lipidomic assay, comprising 244 lipids from six major classes. This assay allowed us to perform robust analyses and assess the changes in averages of broader lipid-classes, stratified on the basis of saturation index of their fatty-acyl side chains.
Methods: Global lipidomic profiling using Liquid Chromatography-Mass Spectrometry was performed to assess lipidomic profiles of biologically diverse cancer cell lines cultivated under metabolically stressed conditions.
Results: Neutral lipid compositions were markedly modified under serum-deprived conditions and, strikingly, the cellular level of triglyceride subspecies decreased with increasing number of double bonds in their fatty acyl chains.
In contrast and unexpectedly, no robust changes were observed in lipidomic profiles of hypoxic (2% O2) Cancer cells despite concurrent changes in proliferation rates and metabolic gene expression.
Conclusions: Serum-deprivation significantly affects lipidomic profiles of cancer cells. Although, the levels of individual lipid moieties alter under hypoxia (2% O2), the robust averages of broader lipid classes remain unchanged.
KW - Tumor metabolism
KW - Fatty acid metabolism
KW - Lipidomic profile
KW - Metabolic stress
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481061
DO - https://doi.org/10.1186/s12885-019-5733-y
SN - 1471-2407
VL - 19
SP - 501, 1
EP - 11
PB - Springer Nature
AN - OPUS4-48106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reed, B.P.
A1 - Radnik, Jörg
A1 - Shard, A.G.
T1 - Ionic liquid [PMIM]+[NTf2]− (Solarpur®) characterized by XPS
N2 - X-ray photoelectron spectroscopy (XPS) was performed on the meniscus of a droplet of ionic liquid 1-propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl) imide [PMIM]+[NTf2]− (Solarpur®) in ultrahigh vacuum. High-resolution spectra of F 1s, O 1s, N 1s, C 1s, and S 2p are presented along with a survey spectrum and the valence band structure. The spectra presented here were generated using monochromatic Al Kα radiation (1486.6 eV).
KW - Ionic liquid
KW - 1-propyl-3-methyl-imidazolium bis(trifluoromethylsulfonyl)imide
KW - X-ray Photoelectron Spectroscopy
PY - 2022
DO - https://doi.org/10.1116/6.0001518
VL - 29
IS - 1
SP - 014001-1
PB - AVS
AN - OPUS4-54335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duewer, D. L.
A1 - Murray, J. A.
A1 - Wood, L. J.
A1 - Wise, S. A.
A1 - Hein, Sebastian
A1 - Koch, Matthias
A1 - Philipp, Rosemarie
A1 - Werneburg, Martina
A1 - Hackenberg, R.
A1 - Polzer, J.
A1 - Avila, M. A.
A1 - Serrano, V.
A1 - Kakoulides, E.
A1 - Alexopoulos, C.
A1 - Giannikopoulou, P.
A1 - Gui, E. M.
A1 - Lu, T.
A1 - Teo, T. L.
A1 - Hua, T.
A1 - Dazhou, C.
A1 - Chunxin, L.
A1 - Changjun, Y.
A1 - Hongmei, L.
A1 - Nammoonnoy, J.
A1 - Sander, L. C.
A1 - Lippa, K.
A1 - Quinn, L.
A1 - Swiegelaar, C.
A1 - Fernandes-Whaley, M.
A1 - Gören, A. C.
A1 - Gökcen, T.
T1 - CCQM-K95.1 Low-polarity analytes in a botanical matrix: Polycyclic aromatic hydrocarbons (PAHs) in tea
N2 - Extraction, chromatographic separation, and quantification of low-concentration organic compounds in complex matrices are core challenges for reference material producers and providers of calibration services. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2014 the Organic Analysis Working Group (OAWG) initiated CCQM-K95.1 "Low-Polarity Analytes in a Botanical Matrix: Polycyclic Aromatic Hydrocarbons (PAHs) in Tea". This was a follow-on comparison from CCQM-K95 which was completed in 2014.
The polycyclic aromatic hydrocarbons (PAHs) benz[a]anthracene (BaA) and benzo[a]pyrene (BaP) are considered priority pollutants by U.S. Environmental Protection Agency and are regulated contaminants in food, pose chromatographic separation challenges, and for which exist well-characterized measurement procedures and standard materials. BaA and BaP in a smoked tea were therefore selected as representative target measurands for CCQM-K95.1. Ten NMIs participated in CCQM-K95.1. The consensus summary mass fractions for the two PAHs are in the range of (50 to 70) ng/g with relative standard deviations of (6 to 10) %.
Successful participation in CCQM K95.1 demonstrates the following measurement capabilities in determining mass fraction of organic compounds, with molar mass of 100 g/mol to 500 g/mol and having polarity pKow −2, in a botanical matrix ranging in mass fraction from 10 ng/g to 1000 ng/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, (3) extraction of analytes of interest from the matrix, (4) cleanup and separation of analytes of interest from interfering matrix or extract components, and (5) separation and quantification using gas chromatography or liquid chromatography.
KW - Benz[a]anthracene (BaA)
KW - Benzo[a]pyrene (BaP)
KW - Gas chromatography (GC)
KW - Isotope dilution (ID)
KW - Liquid chromatography (LC)
KW - Mass spectrometry (MS)
KW - Polycyclic aromatic hydrocarbon (PAH)
KW - Yerba mate tea
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471430
DO - https://doi.org/10.1088/0026-1394/56/1A/08002
SN - 0026-1394
SN - 1681-7575
VL - 56
IS - 1 A
SP - 08002, 1
EP - 89
PB - IOP Science
AN - OPUS4-47143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bühling, Benjamin
A1 - Strangfeld, Christoph
A1 - Maack, Stefan
T1 - Entwicklung eines luftgekoppelten Ultraschall-Echo-Prüfverfahrens mittels fluidischer Anregung
N2 - In vielen technischen Bereichen werden Ultraschallverfahren zur zer-störungsfreien Werkstoffprüfung eingesetzt. Dabei wird ein Schallpuls von einem Prüfkopf in ein Prüfobjekt eingebracht. Der Puls kann unter anderem durch Membra-nen oder Piezoelemente erzeugt werden und wird in der Regel durch direkten Kontakt oder über ein Koppelmittel an das Objekt übertragen. Luftgekoppelter Ultraschall spielt in kommerziellen Anwendungen bisher eine untergeordnete Rolle, da die Dif-ferenz der akustischen Impedanzen von Luft und Festkörpern immense Verluste beim Übergang des Schallsignals hervorruft.
In diesem Beitrag soll ein neuartiges Anregungsprinzip vorgestellt werden, mit dem ein Großteil dieser Verluste vermieden wird. Anstelle eines Festkörpers soll mit Hilfe einer fluidischen Düse Druckluft zur Signalerzeugung eingesetzt werden. In die-ser Düse wird eine selbsterhaltende Strömungsinstabilität erzeugt, die einen Schall-puls von bis zu 100 kHz hervorruft, sodass der Impedanzverlust in die Umgebungsluft entfällt. Da die charakteristische Frequenz eines fluidisch generierten Pulses maßgeb-lich von der Bauform der Düse und dem anliegenden Druck abhängt, lässt sich mittels einer geeigneten Strömungsregelung ein breiter Frequenzbereich zur Abtastung nut-zen. Die so emittierten Pulse werden auf das Prüfobjekt gerichtet und die reflektierten Signale mit einem Laservibrometer an der Oberfläche des Objekts im Echo-Verfahren abgetastet. Von drei signalmindernden Materialübergängen bei gewöhnlichem luftge-koppeltem Ultraschall bleibt in dem hier vorgeschlagenen Messystem lediglich die Grenzfläche von Luft zu Prüfkörper, sodass eine höhere Signalausbeute als bisher er-wartet werden kann.
T2 - DACH-Jahrestagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Ultraschall
KW - Ultrasound
KW - Air-coupled
KW - Luftgekoppelt
KW - Fluidic oscillator
KW - Fluidischer Oszillator
KW - Laser-Doppler-Vibrometer
KW - Refraktovibrometrie
KW - Refracto-vibrometry
KW - NDT
KW - ZfP
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481207
VL - 2019
SP - 1
EP - 8
PB - DGZfP Deutsche Gesellschaft für Zerstörungsfreie Prüfung
AN - OPUS4-48120
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nitz, Phillip D. H.
A1 - Rosaz, Paul
A1 - Kreysina, Daniela
A1 - Kasprzak, Dawid
A1 - Qi, Naiyu
A1 - Baller, Johannes
A1 - Graeber, Gustav
T1 - Water-in-Salt Electrolytes Embedded in Polyacrylamide Hydrogels: A First Step toward Deformable Sodium-Ion Batteries
N2 - The development of flexible, safe, and sustainable Energy storage systems is critical for next-generation technologies, including wearable electronics, biomedical devices, and soft robotics. In this work, we provide a systematic investigation of sodium perchlorate-based water-in-salt (WIS) electrolytes embedded in polyacrylamide (PAM) hydrogels as a potential platform for deformable sodium-ion batteries or aqueous supercapacitors. Using Raman spectroscopy, we track the transition from free to intermediate water states with increasing salt concentration, identifying the onset of the WIS regime around 10 mol kg−1. Electrochemical measurements reveal that both the aqueous and hydrogel-based electrolytes exhibit a broadened electrochemical stability window (ESW) at higher salt concentrations, reaching up to 2.75 V. Impedance spectroscopy shows that while aqueous electrolytes achieve higher peak conductivity (156 mS cm−1), hydrogel-based electrolytes offer greater stability across a range of concentrations. This observation was supported by cyclic voltammetry, as it showed enhanced electrochemical stability of the PAM hydrogel compared to the aqueous electrolyte. This comprehensive and systematic study demonstrates that highly concentrated WIS electrolytes can be successfullyembedded into PAM hydrogels, while preserving good electrochemical stability and ionic conductivity. This could make them a promising foundation for all-hydrogel, sodium-based energy storage devices that are safe, sustainable, and mechanically compliant.
KW - Battery
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653156
DO - https://doi.org/10.1021/acsapm.5c03031
SN - 2637-6105
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-65315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Wohlleben, W.
A1 - Mielke, Johannes
A1 - Hodoroaba, Vasile-Dan
A1 - Zimathies, Annett
A1 - Bianchin, A.
A1 - Lecloux, A.
A1 - Roebben, G.
A1 - Rauscher, H.
A1 - Gibson, N.
T1 - Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial
N2 - The VSSA approach has the important advantage over classifying, imaging and counting techniques that it does not involve dispersion protocols. Further, the BET technique as the basis for VSSA determination it is in widespread use, generates low costs and is specified for many commercial materials. Finally, the same equipment allows for a deeper analysis by full isotherm evaluation.
The present deliverable assesses all NanoDefine powders, supplemented by further real-world materials (in total 26 powders), and quantitatively compares the relationship between the median size (by Electron Microscopy – considered as benchmark for the EC nanomaterial definition) vs. the size derived from VSSA. The VSSA method mitigates the challenges of EM to assess the thickness of platelets, but worked as well on fibbers and particles of irregular shapes. A screening strategy is proposed. If applied to the further data from real-world materials as validation set, this screening does achieve a correct classification, leaving only borderline materials for tier 2 assessment.
KW - Nanomaterial
KW - Classification
KW - Regulation
KW - VSSA
KW - Size measurement
KW - Particle size
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-398938
DO - https://doi.org/10.1007/s11051-017-3741-x
SP - 1
EP - 26
PB - The NanoDefine Consortium
CY - Wageningen, The Netherlands
AN - OPUS4-39893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Hodoroaba, Vasile-Dan
A1 - Mielke, Johannes
T1 - Techniques evaluation report for selection of characterisation methods
N2 - This report is the result of a comprehensive study on the available CMs which come potentially in question for the reliable analysis of the number based size distribution of a nanomaterial according to the EC recommendation for a definition of nanomaterial. Based on the performance criteria already established in NanoDefine the potential CMs are evaluated according to studies available in the literature as well as following the expertise of the NanoDefine consortium partners. The specific advantages and disadvantages of each method with respect to its applicability to the scope of NanoDefine are particularly highlighted. An CM evaluation table is produced so that the mostly suited CMs with respect to the EC definition can be grouped and recommended to the corresponding NanoDefine work packages for further specific development (improvement and adaption), or for direct validation and standardisation, respectively. The actual evaluation report including the recommended CMs will be revised and, if necessary, eventually updated at the mid time of the project. The update will be jointly discussed in the NanoDefine consortium on the basis of the results of testing the methods on the NanoDefine real world materials.
KW - Nanomaterial
KW - Characterization method
KW - EC definition
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389473
UR - http://www.nanodefine.eu/publications/reports/NanoDefine_TechnicalReport_D3.1.pdf
SP - D3.1, 1
EP - 57
CY - Wageningen, The Netherlands
AN - OPUS4-38947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dhamo, Lorena
A1 - Wegner, Karl David
A1 - Würth, Christian
A1 - Häusler, I.
A1 - Hodoroaba, Vasile-Dan
A1 - Resch-Genger, Ute
T1 - Assessing the influence of microwave-assisted synthesis parameters and stabilizing ligands on the optical properties of AIS/ZnS quantum dots
N2 - Luminescent semiconductor quantum dots (QDs) are frequently used in the life and material sciences as reporter for bioimaging studies and as active components in devices such as displays, light-emitting diodes, solar cells, and sensors. Increasing concerns regarding the use of toxic elements like cadmium and lead, and hazardous organic solvents during QD synthesis have meanwhile triggered the search for heavy-metal free QDs using green chemistry syntheses methods. Interesting candidates are ternary AgInS2 (AIS) QDs that exhibit broad photoluminescence (PL) bands, large effective Stokes shifts, high PL quantum yields (PL QYs), and long PL lifetimes, which are particularly beneficial for applications such as bioimaging, white light-emitting diodes, and solar concentrators. In addition, these nanomaterials can be prepared in high quality with a microwave-assisted (MW) synthesis in aqueous solution. The homogeneous heat diffusion and instant temperature rise of the MW synthesis enables a better control of QD nucleation and growth and thus increases the batch-to-batch reproducibility. In this study, we systematically explored the MW synthesis of AIS/ZnS QDs by varying parameters such as the order of reagent addition, precursor concentration, and type of stabilizing thiol ligand, and assessed their influence on the optical properties of the resulting AIS/ZnS QDs. Under optimized synthesis conditions, water-soluble AIS/ZnS QDs with a PL QY of 65% and excellent colloidal and long-term stability could be reproducible prepared.
KW - Quantum dots
KW - Microwave-assisted synthesis
KW - AgInS
KW - Aqueous synthesis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567091
DO - https://doi.org/10.1038/s41598-022-25498-3
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 11
PB - Nature Publishing Group
CY - London
AN - OPUS4-56709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Kersting, R.
A1 - Hagenhoff, B.
A1 - Bennet, Francesca
A1 - Ciornii, Dmitri
A1 - Nymark, P.
A1 - Grafström, R.
A1 - Hodoroaba, Vasile-Dan
T1 - Reliable Surface Analysis Data of Nanomaterials in Support of Risk Assessment Based on Minimum Information Requirements
N2 - The minimum information requirements needed to guarantee high-quality surface Analysis data of nanomaterials are described with the aim to provide reliable and traceable Information about size, shape, elemental composition and surface chemistry for risk assessment approaches.
The widespread surface analysis methods electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS) were considered. The complete analysis sequence from sample preparation, over measurements, to data analysis and data format for reporting and archiving is outlined. All selected methods are used in surface analysis since many years so that many aspects of the analysis (including (meta)data formats) are already standardized. As a practical analysis use case, two coated TiO2 reference nanoparticulate samples, which are available on the Joint Research Centre (JRC) repository, were selected. The added value of the complementary analysis is highlighted based on the minimum information requirements, which are well-defined for the analysis methods selected. The present paper is supposed to serve primarily as a source of understanding of the high standardization level already available for the high-quality data in surface analysis of nanomaterials as reliable input for the nanosafety community.
KW - Electron microscopy
KW - X-ray photoelectron spectroscopy
KW - Secondary ion mass spectrometry
KW - Energy dispersive X-ray spectroscopy
KW - Standardization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522683
DO - https://doi.org/10.3390/nano11030639
VL - 11
IS - 3
SP - 639
PB - MDPI
AN - OPUS4-52268
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brüngel, R.
A1 - Rückert, J.
A1 - Wohlleben, W.
A1 - Babick, F.
A1 - Ghanem, A.
A1 - Gaillard, C.
A1 - Mech, A.
A1 - Rauscher, H.
A1 - Hodoroaba, Vasile-Dan
A1 - Weigel, S.
A1 - Friedrich, C. M.
T1 - NanoDefiner e-Tool: An Implemented Decision Support Framework for Nanomaterial Identification
N2 - The European Commission’s recommendation on the definition of nanomaterial (2011/696/EU) established an applicable standard for material categorization. However, manufacturers face regulatory challenges during registration of their products. Reliable categorization is difficult and requires considerable expertise in existing measurement techniques (MTs). Additionally, organizational complexity is increased as different authorities’ registration processes require distinct reporting.
The NanoDefine project tackled these obstacles by providing the NanoDefiner e-tool: A decision support expert system for nanomaterial identification in a regulatory context. It providesMT recommendations for categorization of specific materials using a tiered approach (screening/confirmatory), and was constructed with experts from academia and industry to be extensible, interoperable, and adaptable for forthcoming revisions of the nanomaterial definition. An implemented MT-driven material categorization scheme allows detailed description. Its guided workflow is suitable for a variety of user groups. Direct feedback and explanation enable transparent decisions. Expert knowledge is Held in a knowledge base for representation of MT performance criteria and physicochemical particle type
properties. Continuous revision ensured data quality and validity. Recommendations were validated by independent case studies on industry-relevant particulate materials. Besides supporting material identification and registration, the free and open-source e-tool may serve as template for other expert systems within the nanoscience domain.
KW - EC nanomaterial definition
KW - Decision support
KW - Expert system
KW - Nanomaterial
KW - Nanoparticles
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492449
DO - https://doi.org/10.3390/ma12193247
VL - 12
IS - 19
SP - 3247
PB - MDPI
CY - Basel, CH
AN - OPUS4-49244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Al-Waqfi, R. A.
A1 - Khan, C. J.
A1 - Irving, O. J.
A1 - Matthews, Lauren
A1 - Albrecht, T.
T1 - Crowding Effects during DNA Translocation in Nanopipettes
N2 - Quartz nanopipettes are an important emerging class of electric single-molecule sensors for DNA, proteins, their complexes, as well as other biomolecular targets. However, in comparison to other resistive pulse sensors, nanopipettes constitute a highly asymmetric environment and the transport of ions and biopolymers can become strongly directiondependent. For double-stranded DNA, this can include the characteristic translocation time and tertiary structure, but as we show here, nanoconfinement can also unlock capabilities for biophysical and bioanalytical studies at the single-molecule level. To this end, we show how the accumulation of DNA inside the nanochannel leads to crowding effects, and in some cases reversible blocking of DNA entry, and provide a detailed analysis based on a range of different DNA samples and experimental conditions. Moreover, using biotin-functionalized DNA and streptavidinmodified gold nanoparticles as target, we demonstrate in a proof-of-concept study how the crowding effect, and the resulting increased residence time in nanochannel, can be exploited by first injecting the DNA into the nanochannel, followed by incubation with the nanoparticle target and analysis of the complex by reverse translocation. We thereby integrate elements of sample processing and detection into the nanopipette, as an important conceptual advance, and make a case for the wider applicability of this device concept.
KW - DNA translocation
KW - Transport
KW - Resistive-pulse sensing
KW - Nanopores
KW - Nanopipettes
KW - Crowding
KW - Confinement
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630448
DO - https://doi.org/10.1021/acsnano.5c01529
SN - 1936-086X
VL - 19
IS - 17
SP - 1
EP - 9
PB - ACS Publications
AN - OPUS4-63044
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferrari, Bruno
A1 - Fantin, Andrea
A1 - Said, D.
A1 - Fitch, A. N.
A1 - Suárez Ocano, Patricia
A1 - Mishurova, Tatiana
A1 - Roveda, Ilaria
A1 - Kromm, Arne
A1 - Darvishi Kamachali, Reza
A1 - Bruno, Giovanni
A1 - Evans, Alexander
A1 - Requena, G.
A1 - Agudo Jácome, Leonardo
A1 - Serrano Munoz, Itziar
T1 - The impact of scanning strategy on cell structures in PBF-LB/M/IN718: an in situ synchrotron x-ray diffraction study
N2 - In additive manufacturing, any change of the process parameters, such as scanning strategy, directly affects the cooling rates, heat accumulation, and overall thermal history of the build. Consequently, parts built with different process parameters tend to have different levels of crystallographic texture, residual stress, and dislocation density. These features can influence the properties of the material and their development during post-processing operations. In this study, IN718 prisms were built by laser powder bed fusion (PBF-LB/M) using two different scanning strategies (continuous 67° rotations around the build direction, ROT, and alternating 0°/67° scans, ALT) to provide two different as-built conditions. In situ time-resolved synchrotron diffraction was performed during a solution heat treatment at 1027 °C for 1 h. Ex situ scanning electron microscopy was used to support and complement the in situ observations. An approach to quantify the effect of elemental microsegregation at the cell walls is developed based on the deconvolution of asymmetric γ-nickel matrix peaks. Following this approach, the scanning strategies are shown to affect the as-built fraction of cell walls in the material, resulting in a difference of approximately 5 %, in weight fraction, between ROT and ALT (19 % vs. 24 %, respectively). This microsegregation was observed to be rapidly homogenized during the heating ramp, and no significant changes to the peak shape in the γ peaks occurred during the isothermal part of the heat treatment, regardless of the scanning strategy.
KW - Additive manufacturing
KW - Inconel 718
KW - Synchrotron x-ray diffraction
KW - Heat treatment
KW - Laser powder bed fusion
KW - Cellular microstructure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650958
DO - https://doi.org/10.1016/j.jmrt.2025.11.214
SN - 2238-7854
VL - 41
SP - 593
EP - 608
PB - Elsevier B.V.
AN - OPUS4-65095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mehta, B.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Markötter, Henning
A1 - Bruno, Giovanni
A1 - Hryha, E.
A1 - Nyborg, L.
A1 - Virtanen, E.
T1 - Microstructure, mechanical properties and fracture mechanisms in a 7017 aluminium alloy tailored for powder bed fusion – laser beam
N2 - This study addressed a 7017 Al-alloy tailored for powder bed fusion – laser beam (PBF-LB) process. The alloy was prepared by mixing 3 wt% Zr and 0.5 wt% TiC powder to standard pre-alloyed 7017 grade aluminium powder. This made printing of the alloys possible avoiding solidification cracking in the bulk and achieving high relative density (99.8 %). Such advanced alloys have significantly higher Young’s modulus (>80 GPa) than conventional Al-alloys (70–75 GPa), thus making them attractive for applications requiring high stiffness. The resulting microstructure in as-printed condition was rich in particles originating from admixed powders and primary precipitates/inclusions originating from the PBF-LB process. After performing a T6-like heat treatment designed for the PBF-LB process, the microstructure changed: Zr-nanoparticles and Fe- or Mg/Zn- containing precipitates formed thus providing 75 % increase in yield strength (from 254 MPa to 444 MPa) at the cost of decreasing ductility (∼20 % to ∼9 %). In-situ tensile testing combined with SXCT, and ex-situ tensile testing combined with fracture analysis confirmed that the fracture initiation in both conditions is highly dependent on defects originated during printing. However, cracks are deflected from decohesion around Zr-containing inclusions/precipitates embedded in the Al-matrix. This deflection is seen to improve the ductility of the material.
KW - Additive manufacturing
KW - Powder bed fusion Laser beam
KW - X-ray computed tomography
KW - Strengthening mechanisms
KW - Crack propagation
KW - Zirconium
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568243
DO - https://doi.org/10.1016/j.matdes.2023.111602
SN - 0264-1275
VL - 226
SP - 1
EP - 14
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-56824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Léonard, Fabien
A1 - Zhang, Zhen
A1 - Krebs, Holger
A1 - Bruno, Giovanni
T1 - Structural and Morphological Quantitative 3D Characterisation of Ammonium Nitrate Prills by X-ray Computed Tomography
N2 - The mixture of ammonium nitrate (AN) prills and fuel oil (FO), usually referred to as ANFO, is extensively used in the mining industry as a bulk explosive. One of the major performance predictors of ANFO mixtures is the fuel oil retention, which is itself governed by the complex pore structure of the AN prills. In this study, we present how X-ray computed tomography (XCT), and the associated advanced data processing workflow, can be used to fully characterise the structure and morphology of AN prills. We show that structural parameters such as volume fraction of the different phases and morphological parameters such as specific surface area and shape factor can be reliably extracted from the XCT data, and that there is a good agreement with the measured oil retention values. Importantly, oil retention measurements (qualifying the efficiency of ANFO as explosives) correlate well with the specific surface area determined by XCT. XCT can therefore be employed non-destructively; it can accurately evaluate and characterise porosity in ammonium nitrate prills, and even predict their efficiency.
KW - ANFO
KW - Explosives
KW - Surface area
KW - Porosity
KW - XCT
KW - Data processing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505395
DO - https://doi.org/10.3390/ma13051230
VL - 13
IS - 5 (Special Issue "Micro Non-Destructive Testing and Evaluation")
SP - 1230
PB - MDPI
AN - OPUS4-50539
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Oster, Simon
A1 - Maierhofer, Christiane
A1 - Bruno, Giovanni
ED - Czujko, T.
ED - Benedetti, M.
T1 - Can Potential Defects in LPBF Be Healed from the Laser Exposure of Subsequent Layers? A Quantitative Study
N2 - Additive manufacturing (AM) of metals and in particular laser powder bed fusion (LPBF) enables a degree of freedom in design unparalleled by conventional subtractive methods. To ensure that the designed precision is matched by the produced LPBF parts, a full understanding of the interaction between the laser and the feedstock powder is needed. It has been shown that the laser also melts subjacent layers of material underneath. This effect plays a key role when designing small cavities or overhanging structures, because, in these cases, the material underneath is feed-stock powder. In this study, we quantify the extension of the melt pool during laser illumination of powder layers and the defect spatial distribution in a cylindrical specimen. During the LPBF process, several layers were intentionally not exposed to the laser beam at various locations, while the build process was monitored by thermography and optical tomography. The cylinder was finally scanned by X-ray computed tomography (XCT). To correlate the positions of the unmolten layers in the part, a staircase was manufactured around the cylinder for easier registration. The results show that healing among layers occurs if a scan strategy is applied, where the orientation of the hatches is changed for each subsequent layer. They also show that small pores and surface roughness of solidified material below a thick layer of unmolten material (>200 µm) serve as seeding points for larger voids. The orientation of the first two layers fully exposed after a thick layer of unmolten powder shapes the orientation of these voids, created by a lack of fusion.
KW - Computed tomography
KW - Laser Powder Bed Fusion
KW - In situ monitoring
KW - infrared Thermography
KW - Optical Tomography
KW - Additive manufacturing
KW - AISI 316L
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528778
DO - https://doi.org/10.3390/met11071012
VL - 11
IS - 7
SP - 1012
PB - MDPI
CY - Basel
AN - OPUS4-52877
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ziesche, R.F.
A1 - Hack, J.
A1 - Rasha, L.
A1 - Maier, M.
A1 - Tan, C.
A1 - Heenan, T.M.M.
A1 - Markötter, Henning
A1 - Kardjilov, N.
A1 - Manke, I.
A1 - Kockelmann, W.
A1 - Brett, D.J.L.
A1 - Shearing, P.R.
T1 - High-speed 4D neutron computed tomography for quantifying water dynamics in polymer electrolyte fuel cells
N2 - In recent years, low-temperature polymer electrolyte fuel cells have become an increasingly important pillar in a zero-carbon strategy for curbing climate change, with their potential to power multiscale stationary and mobile applications. The performance improvement is a particular focus of research and engineering roadmaps, with water management being one of the major areas of interest for development. Appropriate characterisation tools for mapping the evolution, motion and removal of water are of high importance to tackle shortcomings.
This article demonstrates the development of a 4D high-speed neutron imaging technique, which enables a quantitative analysis of the local water evolution. 4D visualisation allows the time-resolved studies of droplet formation in the flow fields and water quantification in various cell parts. Performance parameters for water management are identified that offer a method of cell classification, which will, in turn, support computer modelling and the engineering of next-generation flow field designs.
KW - Neutron imaging
KW - Tomography
KW - Polymer electrolyte membrane fuel cell
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545978
DO - https://doi.org/10.1038/s41467-022-29313-5
VL - 13
IS - 1
SP - 1616
PB - Nature Publishing Group UK
CY - London
AN - OPUS4-54597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Fernández, R.
A1 - Saliwan Neumann, Romeo
A1 - González-Doncel, G.
A1 - Bruno, Giovanni
T1 - Dislocation substructures in pure aluminium after creep deformation as studied by electron backscatter diffraction
N2 - In the present work, electron backscatter diffraction was used to determine the microscopic dislocation structures generated during creep (with tests interrupted at the steady state) in pure 99.8% aluminium. This material was investigated at two different stress levels, corresponding to the power-law and power-law breakdown regimes. The results show that the formation of subgrain cellular structures occurs independently of the crystallographic orientation. However, the density of these cellular structures strongly depends on the grain crystallographic orientation with respect to the tensile axis direction, with <111> grains exhibiting the highest densities at both stress levels. It is proposed that this behaviour is due to the influence of intergranular stresses, which is different in <111> and <001> grains.
KW - Creep
KW - Pure aluminium
KW - Electron backscatter diffraction
KW - Cellular structures
KW - Power law and power-law breakdown
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552003
DO - https://doi.org/10.1107/S1600576722005209
SN - 0021-8898
SN - 1600-5767
VL - 55
SP - 860
EP - 869
PB - Wiley-Blackwell
CY - Copenhagen
AN - OPUS4-55200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bruno, Giovanni
A1 - Hentschel, Manfred P.
A1 - Onel, Yener
A1 - Lange, Axel
A1 - Kupsch, Andreas
A1 - Wolk, Thomas
A1 - Staude, Andreas
A1 - Ehrig, Karsten
A1 - Müller, Bernd R.
T1 - Bewertung von Porositätsparametern in Cordierit-Diesel-Partikelfilter-Materialien mit fortgeschrittenen Röntgenverfahren und statistischer Analyse
N2 - Bikontinuierliche poröse Keramiken für Filteranwendungen weisen eine komplizierte Mikrostruktur auf, in der Poren und Festkörperphase 'vermischt' sind. Mechanische, thermische sowie Filtereigenschaften können nur präzise bestimmt werden, wenn die Morphologie beider Phasen quantitativ angegeben werden kann. Hier werden unter Anwendung von 3D Computertomographie (CT) und verschiedenen Techniken, die auf der Röntgenrefraktion basieren, die Porosität und die Porenorientierung in keramischen Cordierit-Dieselpartikelfiltern bewertet. Dabei werden zur Auswertung der Tomogramme die Fouriertransformierten sowie eine neu entwickelte richtungssensitive Bildanalyse (DIVA, directional interface variance analysis) angewandt. Sowohl die genannten Messtechniken als auch der statistische Ansatz gestatten die Extraktion optional ortsaufgelöster oder gemittelter Werte. Es ergeben sich sehr gute Übereinstimmungen der experimentell ermittelten Porositätswerte mit Ergebnissen aus Quecksilberintrusionsversuchen als auch der ermittelten Porenorientierung im Vergleich zu publizierten Angaben zur kristallographischen Textur. Dies legt den Schluss nahe, dass die Kenntnis der Grenzflächen (zwischen Poren und Materie) genügt, die morphologischen Eigenschaften solcher Materialien hinreichend zu beschreiben.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Cordierit
KW - Poröse Keramik
KW - Porenorientierung
KW - Röntgenrefraktion
KW - Computer-Tomographie
KW - 3D-Mikrostruktur
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312946
SN - 978-3-940283-61-0
VL - 148
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31294
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tsamos, Athanasios
A1 - Evsevleev, Sergei
A1 - Bruno, Giovanni
T1 - Noise and blur removal from corrupted X-ray computed tomography scans: A multilevel and multiscale deep convolutional framework approach with synthetic training data (BAM SynthCOND)
N2 - Regardless of the experimental care practiced in acquiring X-ray computed tomography (XCT) data, artifacts might still exist, such as noise and blur. This is typical for fast XCT data acquisitions (e.g., in-situ investigations), or low-dose XCT. Such artifacts can complicate subsequent analysis of the data. Digital filters can moderately cure extensive artifacts. The selection of filter type, intensity, and order of application is not always straight forward. To tackle these problems, a complete sequential multilevel, multi-scale framework: BAM SynthCOND, employing newly designed deep convolutional neural networks (DCNNs), was formulated. Although data conditioning with neural networks is not uncommon, the main complication is that completely artifact-free XCT data for training do not exist. Thus, training data were acquired from an in-house developed library (BAM SynthMAT) capable of generating synthetic XCT material microstructures. Some novel DCNN architectures were introduced (2D/3D ACEnet_Denoise, 2D/3D ACEnet_Deblur) along with the concept of Assertive Contrast Enhancement (ACE) training, which boosts the performance of neural networks trained with continuous loss functions. The proposed methodology accomplished very good generalization from low resemblance synthetic training data. Indeed, denoising, sharpening (deblurring), and even ring artifact removal performance were achieved on experimental post-CT scans of challenging multiphase Al-Si Metal Matrix Composite (MMC) microstructures. The conditioning efficiencies were: 92% for combined denoising/sharpening, 99% for standalone denoising, and 95% for standalone sharpening. The results proved to be independent of the artifact intensity. We believe that the novel concepts and methodology developed in this work can be directly applied on the CT projections prior to reconstruction, or easily be extended to other imaging techniques such as: Microscopy, Neutron Tomography, Ultrasonics, etc.
KW - XCT Data Conditioning
KW - Denoising Deblurring Sharpening
KW - Deep Convolutional Neural Network (DCNN)
KW - Synthetic Training Data
KW - ACEnet
KW - Metal Matrix Composite (MMC)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579129
DO - https://doi.org/10.1016/j.tmater.2023.100011
VL - 2
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-57912
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Mack, D. E.
A1 - Laquai, René
A1 - Kupsch, Andreas
A1 - Helle, O.
A1 - Sebold, D.
A1 - Vaßen, R.
A1 - Bruno, Giovanni
T1 - Charakterisierung der Porositäts- und Rissdichteentwicklung in Wärmedämmschichten von Gasturbinenschaufeln mittels Synchrotron Refraktions Radiographie
N2 - Die Degradation von Wärmedämmschichten(thermal barrier coatings - TBCs) in Gasturbinen durch glasartige Calcium-Magnesium-Aluminiumsilikat (CMAS)Ablagerungen aus verschiedenen Quellen istseit vielen Jahren ein anhaltendes Problem. In dieser Studie wurde mit Hilfe derSynchrotron-Röntgen-Refraktions-Radiographie (SXRR), und vergleichend mit der Elektronenmikroskopie, das Eindringen von CMAS in die poröse Struktur von atmosphärisch plasmagespritzten (APS)TBCs sowie die Bildung und das Wachstum von Rissen unter thermisch zyklischer Belastung untersucht. Die Ergebnisse deuten darauf hin, dass die Infiltration sowie deren Kinetik im Brenner-Teststand wesentlich vom Benetzungsverhalten des CMAS beeinflusst werden. Trotz desoffensichtlichen Angriffs von CMAS auf die Korngrenzen hat die Wechselwirkung von Yttriumdioxid-stabilisiertem Zirkoniumdioxid (YSZ) mit intrudiertem CMAS keinen unmittelbaren Einfluss auf die Struktur und Dichte der innen Oberflächen(Risse, Poren). In einem späteren Stadium wird die Bildung von Rissen senkrecht zur äußeren Oberfläche in einer breiteren Zone der TBC-Schicht beobachtet.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - CMAS - Calcium-Magnesium-Aluminiumsilikat
KW - SXRR - Synchrotron X-ray Refraction Radiography
KW - TBC - Thermal barrier coatings
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526732
UR - https://jahrestagung.dgzfp.de/Programm#P32
SP - 1
EP - 15
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-52673
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evans, Alexander
A1 - Schröder, Jakob
A1 - Pirling, T.
A1 - Ulbricht, Alexander
A1 - Suárez Ocaño, Patricia
A1 - Bruno, Giovanni
T1 - Resolving the Subsurface Residual Stress Maximum in Laser Powder Bed-Fused 316L Stainless Steel by Diffraction-Based Analysis
N2 - Laser powder bed fusion (PBF-LB/M) is a metal additive manufacturing process. Due to the complex nature of the layer-wise, repeated heating and cooling cycles, it tends to generate high-magnitude residual stresses. If not correctly understood and mitigated through in- or post-process approaches, these residual stresses can be detrimental as they are often tensile at the surface. However, determining the magnitude and location of peak tensile residual stresses is not trivial as they are often located subsurface. This work focuses on determining the magnitude and location of these deleterious tensile residual stresses in a PBF-LB/316L specimen. Two diffraction-based Methods are used to reveal the relationship between the residual stresses and the underlying microstructure. On the one hand, high spatial resolution Neutron diffraction is used to determine triaxial stresses from the bulk to a depth of 0.15 mm. On the other hand, laboratory X-ray diffraction coupled with electrolytical layer removal allows the biaxial residual stress depth profile to be probed from the surface to a depth of about 0.6 mm. The results show a good agreement between the two methods. The peak residual stress is shown to be 500 MPa, which appears as a plateau between 0.08 and 0.35 mm in depth.
KW - Residual stress
KW - Diffraction
KW - Laser Powder Bed Fusion
KW - 316L
KW - Additive manufacturing
KW - Microstructure
KW - AGIL
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652138
DO - https://doi.org/10.1007/s11837-025-07719-y
SN - 1543-1851
VL - 77
IS - 12
SP - 9726
EP - 9737
PB - Springer Nature
AN - OPUS4-65213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evsevleev, Sergei
A1 - Paciornik, S.
A1 - Bruno, Giovanni
T1 - Advanced Deep Learning-Based 3D Microstructural Characterization of Multiphase Metal Matrix Composites
N2 - The quantitative analysis of microstructural features is a key to understanding the micromechanical behavior of metal matrix composites (MMCs), which is a premise for their use in practice. Herein, a 3D microstructural characterization of a five-phase MMC is performed by synchrotron X-ray computed tomography (SXCT). A workflow for advanced deep learning-based segmentation of all individual phases in SXCT data is shown using a fully convolutional neural network with U-net architecture. High segmentation accuracy is achieved with a small amount of training data. This enables extracting unprecedently precise microstructural parameters (e.g., volume fractions and particle shapes) to be input, e.g., in micromechanical models.
KW - Computed tomography
KW - Convolutional neural networks
KW - Deep learning
KW - Metal matrix composites
KW - Segmentations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504261
DO - https://doi.org/10.1002/adem.201901197
SN - 1438-1656
VL - 22
IS - 4
SP - 1901197
PB - WILEY-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50426
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Evans, Alexander
A1 - Polatidis, E.
A1 - Čapek, J.
A1 - Mohr, Gunther
A1 - Serrano-Munoz, Itziar
A1 - Bruno, Giovanni
T1 - Understanding the impact of texture on the micromechanical anisotropy of laser powder bed fused Inconel 718
N2 - The manufacturability of metallic alloys using laser-based additive manufacturing methods such as laser powder bed fusion has substantially improved within the last decade. However, local melting and solidification cause hierarchically structured and crystallographically textured microstructures possessing large residual stress. Such microstructures are not only the origin of mechanical anisotropy but also pose metrological challenges for the diffraction-based residual stress determination. Here we demonstrate the influence of the build orientation and the texture on the microstructure and consequently the mechanical anisotropy of as-built Inconel 718. For this purpose, we manufactured specimens with [001]/[011]-, [001]- and [011]/[111]-type textures along their loading direction. In addition to changes in the Young’s moduli, the differences in the crystallographic textures result in variations of the yield and ultimate tensile strengths. With this in mind, we studied the anisotropy on the micromechanical scale by subjecting the specimens to tensile loads along the different texture directions during in situ neutron diffraction experiments. In this context, the response of multiple lattice planes up to a tensile strain of 10% displayed differences in the load partitioning and the residual strain accumulation for the specimen with [011]/[111]-type texture. However, the relative behavior of the specimens possessing an [001]/[011]- and [001]-type texture remained qualitatively similar. The consequences on the metrology of residual stress determination methods are discussed.
KW - Laser powder bed fusion
KW - Additive manufacturing
KW - Electron backscatter diffraction
KW - Tensile testing
KW - Diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555840
DO - https://doi.org/10.1007/s10853-022-07499-9
SN - 1573-4803
VL - 2022
IS - 57
SP - 15036
EP - 15058
PB - Springer Science + Business Media B.V.
CY - Dordrecht
AN - OPUS4-55584
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oster, Simon
A1 - Fritsch, Tobias
A1 - Ulbricht, Alexander
A1 - Mohr, Gunther
A1 - Bruno, Giovanni
A1 - Maierhofer, Christiane
A1 - Altenburg, Simon
T1 - On the Registration of Thermographic In Situ Monitoring Data and Computed Tomography Reference Data in the Scope of Defect Prediction in Laser Powder Bed Fusion
N2 - The detection of internal irregularities is crucial for quality assessment in metal-based additive manufacturing (AM) technologies such as laser powder bed fusion (L-PBF). The utilization of in-process thermography as an in situ monitoring tool in combination with post-process X-ray micro computed tomography (XCT) as a reference technique has shown great potential for this aim. Due to the small irregularity dimensions, a precise registration of the datasets is necessary as a
requirement for correlation. In this study, the registration of thermography and XCT reference datasets of a cylindric specimen containing keyhole pores is carried out for the development of a porosity prediction model. The considered datasets show variations in shape, data type and dimensionality, especially due to shrinkage and material elevation effects present in the manufactured part. Since the resulting deformations are challenging for registration, a novel preprocessing methodology is introduced that involves an adaptive volume adjustment algorithm which is based on the porosity distribution in the specimen. Thus, the implementation of a simple three-dimensional image-to-image registration is enabled. The results demonstrate the influence of the part deformation on the resulting porosity location and the importance of registration in terms of irregularity prediction.
KW - Selective laser melting (SLM)
KW - Laser powder bed fusion (L-PBF)
KW - Additive manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
KW - X-ray computed tomography (XCT)
KW - Defect detection
KW - Image registration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549412
DO - https://doi.org/10.3390/met12060947
VL - 12
IS - 6
SP - 1
EP - 21
PB - MDPI
AN - OPUS4-54941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sprengel, Maximilian
A1 - Mohr, Gunther
A1 - Altenburg, Simon
A1 - Evans, Alexander
A1 - Serrano-Munoz, Itziar
A1 - Kromm, Arne
A1 - Pirling, T.
A1 - Bruno, Giovanni
A1 - Kannengießer, Thomas
T1 - Triaxial Residual Stress in Laser Powder Bed Fused 316L: Effects of Interlayer Time and Scanning Velocity
N2 - The triaxial distribution of the residual stress in laser powder bed fused austenitic steel 316L was determined by X-ray and neutron diffraction. The residual stress analysis results were linked to the thermal history of the specimens, which were manufactured with varying inter-layer-times and scanning velocities. A clear link between the in-process temperature of the specimens and the residual stress was found, based on in-situ monitoring data.
KW - Stainless Steel
KW - AGIL
KW - Residual Stress
KW - X-ray and Neutron Diffraction
KW - Additive Manufacturing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542620
DO - https://doi.org/10.1002/adem.202101330
SP - 1
EP - 13
PB - Wiley-VCH GmbH
AN - OPUS4-54262
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oesch, Tyler
A1 - Weise, Frank
A1 - Bruno, Giovanni
T1 - Detection and Quantification of Cracking in Concrete Aggregate through Virtual Data Fusion of X-ray Computed Tomography Images
N2 - In this work, which is part of a larger research program, a framework called “virtual data fusion“ was developed to provide an automated and consistent crack detection method that allows for the cross-comparison of results from large quantities of X-ray Computed Tomography (CT) data. A partial implementation of this method in a custom program was developed for use in research focused on crack quantification in Alkali-Silica Reaction (ASR)-sensitive concrete aggregates. During the CT image processing, a series of image analyses tailored for detecting specific, individual crack-like characteristics were completed. The results of these analyses were then “fused” in order to identify crack-like objects within the images with much higher accuracy than that yielded by any individual image analysis procedure. The results of this strategy demonstrated the success of the program in effectively identifying crack-like structures and quantifying characteristics, such as surface area and volume. The results demonstrated that the source of aggregate has a very significant impact on the amount of internal cracking, even when the mineralogical characteristics remain very similar. River gravels, for instance, were found to contain significantly higher levels of internal cracking than quarried stone aggregates of the same mineralogical type.
KW - X-ray Computed Tomography (CT)
KW - Alkali-Silica Reaction (ASR)
KW - Crack Detection
KW - Damage Quantification
KW - ASR-Sensitive Aggregate
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512170
DO - https://doi.org/10.3390/ma13183921
VL - 13
IS - 18
SP - Paper 3921
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-51217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belli, Renan
A1 - Hartmann, Sabine
A1 - Lubauer, Julia
A1 - Pereira, Raíssa Monteiro
A1 - Hurle, Katrin
A1 - Yin, Ling
A1 - Mieller, Björn
A1 - Lohbauer, Ulrich
T1 - Improving the chipping resistance of pre-sintered zirconia white-bodies
N2 - Objectives: The high occurrence of fractures, cracking and chipping of zirconia pre-sintered blanks and blocks during machining decreases their yield and can transfer lifetime-limiting racks to the final sintered restoration. This study has the objective of characterizing the mechanical and fracture properties of two zirconia compositions while varying temperature and time of pre-sintering, in order to assess the space for possible improvement.
Methods: We selected two typical granular powders with 3 mol% (3YSZ, Zpex®, Tosoh) or 5 mol% (5YSZ, Zpex Smile®, Tosoh) yttria-stabilized zirconia and two pre-sintered commercial analogs (IPS e.max® ZirCAD MO, Ivoclar and Katana™ STML, Kuraray). The debinding and pre-sintering stages of the experimental powders were characterized using thermal analyses (differential scanning calorimetry and thermogravimetry), and the crystal phase composition was quantified using X-ray diffraction (XRD). Physical and mechanical properties such as density, hardness, flexural modulus, biaxial flexural strength and fracture toughness were measured for two pre-sintering temperatures (1000 ◦C, 1100 ◦C) and increasing holding times at those temperatures (2 h, 4 h, 6 h). The chipping resistance for those conditions was quantified using the edge chipping test using a Vickers diamond indenter.
Results: Thermal analyses revealed that both powders show comparable debinding behavior and contained approx. 3.8 mass % organic binder, which burns-out completely between 300 and 400 ◦C. The crystallographic phase changes occurring during the 2–6 h at 1000 ◦C and 1100 ◦C was not detectable in the DSC signal, but quantifiable by XRD. Namely, a major content of monoclinic phase in both powders transforms completely into the two tetragonal phases, starting below 1000 ◦C and concluding above 1100 ◦C. All physical and mechanical properties increased with holding time for both temperatures, though more steeply for pre-sintering at 1100◦C. Edge chipping resistance response was well aligned with other fracture properties, with a more marked improvement for 3YSZ pre-sintered at 1100 ◦C. For all properties, the 3YSZ zirconia showed statistically-higher values for the same temperature-time conditions, in agreement with the values obtained for the commercial materials as well.
Significance: The results demonstrate the weakness of pre-sintered zirconia products concerning fracture properties, but also the potential for improvement as related to type of zirconia and pre-sintering conditions. This study outlines the use of a set of mechanical tests that can characterize chipping resistance and guide future research engaging in optimizing the machining resistance of pre-sintered zirconia products.
KW - Zirconia
KW - Fracture
KW - White body
KW - Dental materials
KW - Pre-sintering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653457
DO - https://doi.org/10.1016/j.dental.2025.12.012
SN - 0109-5641
SP - 1
EP - 12
PB - Elsevier Inc.
AN - OPUS4-65345
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Arlt, Tobias
A1 - Grothausmann, R.
A1 - Manke, I.
A1 - Markötter, Henning
A1 - Krüger, P.
A1 - Haussmann, J.
A1 - Hilger, A.
A1 - Kardjilov, N.
A1 - Hartnig, C.
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Wippermann, K.
A1 - Banhart, J.
T1 - Tomografische Methoden für die Brennstoffzellenforschung
N2 - Auf Grund des hohen Wirkungsgrades und der vielfältigen Einsatzmöglichkeiten stellen Brennstoffzellen sowie Brennstoffzellenverbünde eine vielversprechende Energiequelle dar. Daher ist es wichtig, die Prozesse während des Betriebs einer Brennstoffzelle exakt charakterisieren zu können, um diese im nächsten Schritt zu optimieren.
So ist ein ausbalanciertes Wassermanagement in einer mit Wasserstoff betriebenen Zelle ausschlaggebend für ihre Leistungsfähigkeit. Für eine dauerhafte Leistungsfähigkeit muss das entstehende Wasser die Membran feucht halten, um so die Protonenleitfähigkeit aufrecht zu erhalten. Zu viel Wasser kann jedoch die Gaszufuhr durch die porösen Materialien in Richtung Membran verhindern.
Alterungsphänomene der einzelnen Komponenten können dieses sensible Wassermanagement stören und so die Leistungsfähigkeit einer Brennstoffzelle
herabsetzen. Zum tieferen Verständnis der Wasserverteilung werden zerstörungsfreie Methoden, wie zum Beispiel die ex situ Neutronentomografie oder die in situ Synchrotronradiografie eingesetzt. Letztere Methode kann während des Brennstoffzellenbetriebs in Kombination mit weiteren Messmethoden, wie der ortsaufgelösten Stromdichtemessung, eingesetzt werden. So können einzelne Brennstoffzellenkomponenten, wie die Gasdiffusionsschichten, charakterisiert werden.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Computer-Tomographie
KW - Rekonstruktionsalgorithmen
KW - Röntgen-Kanten-Tomographie
KW - Neutronen-Tomographie
KW - Elektronen-Tomographie
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250023
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (P7)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25002
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jamro, R.
A1 - Mente, Tobias
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Al-Falahat, Ala'A. M.
A1 - Woracek, R.
A1 - Manke, I.
A1 - Griesche, Axel
T1 - Temperature distribution during welding measured by neutron imaging
N2 - This study was carried out to investigate the neutron transmission signal as a function of sample temperature during a welding process. A theoretical description that includes the Debye-Waller factor was used to describe the temperature influence on the neutron crosssections. Neutron imaging using a monochromatic beam helps to observe transmission variations related to the material temperature. In-situ neutron imaging of welding experiments show the distribution of the temperature in bulk steel samples. The performed finite element modelling of expected temperature distributions shows good agreement with the obtained experimental data.
KW - Neutron imaging
KW - Debye-Waller-Faktor
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586268
DO - https://doi.org/10.1088/1742-6596/2605/1/012026
VL - 2605
SP - 1
EP - 10
PB - IOP Publishing Ltd.
AN - OPUS4-58626
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rossi, Andrea
A1 - Corrao, Elena
A1 - Alladio, Eugenio
A1 - Drobne, Damjana
A1 - Hodoroaba, Vasile-Dan
A1 - Jurkschat, Kerstin
A1 - Kononenko, Veno
A1 - Madbouly, Loay Akmal
A1 - Mrkwitschka, Paul
A1 - Yasamin, Nakhli
A1 - Novak, Sara
A1 - Radnik, Jörg
A1 - Saje, Špela
A1 - Santalucia, Rosangela
A1 - Sordello, Fabrizio
A1 - Pellegrino, Francesco
T1 - Multivariate optimization and characterization of graphene oxide via design of experiments and chemometric analysis
N2 - Controlling the structure and properties of graphene oxide (GO) remains a challenge due to the poor reproducibility of conventional synthetic protocols and limited understanding of parameter-property relationships. In this study, we present an integrated analytical framework that combines Design of Experiments (DoE) with chemometric modelling to systematically assess the effects of eight synthesis variables on GO’s physicochemical and functional features. A Plackett–Burman experimental design enabled efficient screening of synthesis conditions, while comprehensive characterization (spanning UV–Vis spectroscopy, XPS, SEM–EDX, TEM–EDX, and XRD) was coupled with multivariate tools (Principal Component Analysis and Multiple Linear Regression) to identify statistically significant correlations between synthetic inputs and material responses. Notably, we demonstrate that UV–Vis spectra can serve as a robust proxy for oxidation state, offering a rapid and accessible alternative to surface-sensitive methods. The approach yields a predictive analytical toolkit for guiding GO synthesis and highlights a generalizable strategy for the rational design of flat nanomaterials. This work supports reproducible, resource-efficient material development aligned with Safe and Sustainable by Design (SSbD) principles.
KW - Graphene oxide
KW - 2D-materials
KW - Design of Experiment
KW - Synthesis
KW - Chemometric analysis
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652576
DO - https://doi.org/10.1016/j.flatc.2025.100988
SN - 2452-2627
VL - 55
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Kömmling, Anja
A1 - Zaghdoudi, Maha
A1 - Ghasem Zadeh Khorasani, Media
A1 - Jaunich, Matthias
T1 - Data-driven nanomechanical study of filled fluoroelastomer aged in air and hydrogen atmosphere
N2 - Fluoroelastomer (FKM) composites are typically used as sealing materials in challenging non-ambient environments. Depending on the environment, two main aging mechanisms, chemical aging, and physical aging, can be identified. Chemical aging, the degradation of the elastomer, is present for example in thermal-oxidative conditions and can be directly observed as it affects the bulk. Physical aging, relaxation and rearrangement of the elastomers segmental conformation is commonly observed at elevated temperatures and effects predominantly the elastomer interphase. As a highly localized nanoscopic effect it is usually observed indirectly by phenomological approaches and not systematically understood. In this study, as a typical example for chemical aging, filled FKM was aged in air (150°C, 100 days). Physical aging of FKM was realized by exposure to chemically inert H2 (150°C, 50 bar, 100 days), since temperature and gas-induced swelling is known to promote physical aging. The effects of both conditions are directly compared with the initial unaged material. We use atomic force microscopy (AFM) force spectroscopy as a method to resolve nanoscopic heterogeneous FKM. With this method the effect of aging on the spatially distinguishable material phases was directly observed. In thermal oxidative aged FKM the matrix shows a decrease in van der Waals interactions and stiffness, indicating dehydrofluorination and chain scission. In H2 aged FKM, the development of an immobilized amorphous interphase (IAP) was observed, indicating physical aging. By additionally evaluating a larger data set with supervised machine learning, these observations were validated for a larger, statistically representative sample area, allowing conclusions to be drawn about the macroscopic behaviour of the material.
KW - Fluoroelastomer
KW - Atomic force microscopy
KW - Data-driven
KW - Hydrogen
KW - Ageing mechanism
KW - Physical aging
KW - Polymer interphase
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648154
DO - https://doi.org/10.1016/j.polymdegradstab.2025.111715
SN - 0141-3910
VL - 242
SP - 1
EP - 10
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-64815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hülagü, Deniz
A1 - Tobias, Charlie
A1 - Dao, Radek
A1 - Komarov, Pavel
A1 - Rurack, Knut
A1 - Hodoroaba, Vasile-Dan
T1 - Towards 3D determination of the surface roughness of core–shell microparticles as a routine quality control procedure by scanning electron microscopy
N2 - AbstractRecently, we have developed an algorithm to quantitatively evaluate the roughness of spherical microparticles using scanning electron microscopy (SEM) images. The algorithm calculates the root-mean-squared profile roughness (RMS-RQ) of a single particle by analyzing the particle’s boundary. The information extracted from a single SEM image yields however only two-dimensional (2D) profile roughness data from the horizontal plane of a particle. The present study offers a practical procedure and the necessary software tools to gain quasi three-dimensional (3D) information from 2D particle contours recorded at different particle inclinations by tilting the sample (stage). This new approach was tested on a set of polystyrene core-iron oxide shell-silica shell particles as few micrometer-sized beads with different (tailored) surface roughness, providing the proof of principle that validates the applicability of the proposed method. SEM images of these particles were analyzed by the latest version of the developed algorithm, which allows to determine the analysis of particles in terms of roughness both within a batch and across the batches as a routine quality control procedure. A separate set of particles has been analyzed by atomic force microscopy (AFM) as a powerful complementary surface analysis technique integrated into SEM, and the roughness results have been compared.
KW - Core–shell particles
KW - Image analysis
KW - Roughness
KW - Scanning electron microscopy
KW - Atomic force microscopy
KW - Tilting
KW - Batch analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607590
DO - https://doi.org/10.1038/s41598-024-68797-7
SN - 2045-2322
VL - 14
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-60759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Kai
A1 - Mirabella, Francesca
A1 - Knigge, Xenia
A1 - Mezera, Marek
A1 - Weise, Matthias
A1 - Sahre, Mario
A1 - Wasmuth, Karsten
A1 - Voss, Heike
A1 - Hertwig, Andreas
A1 - Krüger, Jörg
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Bonse, Jörn
T1 - Chemical and topographical changes upon sub-100-nm laser-induced periodic surface structure formation on titanium alloy: the influence of laser pulse repetition rate and number of over-scans
N2 - Titanium and its alloys are known to allow the straightforward laser-based manufacturing of ordered surface nanostructures, so-called high spatial frequency laser-induced periodic surface structures (HSFL). These structures exhibit sub-100 nm spatial periods – far below the optical diffraction limit. The resulting surface functionalities are usually enabled by both, topographic and chemical alterations of the nanostructured surfaces. For exploring these effects, multi-method characterizations were performed here for HSFL processed on Ti–6Al–4V alloy upon irradiation with near-infrared ps-laser pulses (1030 nm, ≈1 ps pulse duration, 1–400 kHz) under different laser scan processing conditions, i.e., by systematically varying the pulse repetition frequency and the number of laser irradiation passes. The sample characterization involved morphological and topographical investigations by scanning electron microscopy (SEM), atomic force microscopy (AFM), tactile stylus profilometry, as well as near-surface chemical analyses hard X-ray photoelectron spectroscopy (HAXPES) and depth-profiling time-of-flight secondary ion mass spectrometry (ToF-SIMS). This provides a quantification of the laser ablation depth, the geometrical HSFL characteristics and enables new insights into the depth extent and the nature of the non-ablative laser-induced near-surface oxidation accompanying these nanostructures. This allows to answer the questions how the processing of HSFL can be industrially scaled up, and whether the latter is limited by heat-accumulation effects.
T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
KW - Laser processing
KW - Hard X-ray photoelectron spectroscopy (HAXPES)
KW - Time-of-flight secondary ion mass spectrometry (ToF-SIMS)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589902
UR - https://onlinelibrary.wiley.com/doi/full/10.1002/pssa.202300719
DO - https://doi.org/10.1002/pssa.202300719
SN - 1862-6319
VL - 221
IS - 15
SP - 1
EP - 12
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-58990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Bütefisch, Sebastian
A1 - Weimann, Thomas
A1 - Hodoroaba, Vasile-Dan
T1 - A New XPS Test Material for More Reliable Analysis of Microstructures
N2 - A reference material is required for small‐area XPS because it has been used more frequently for surface control in recent years and many operators use incorrect field of views. To address this problem, we developed a test material starting in 2019. We optimised this XPS test material dedicated to the control of analysis position on the sample, with respect to the following factors: type of XPS instruments available on the market, the manufacturing process and sample handling. Test structures are now aligned along lines instead of on a circle radius, so that the individual structures can be accessed more quickly and easily. In addition, a larger test structure of 300 μm and another one in an intermediate size of 18 μm were added. Smaller test structures under 50 μm have been annotated with finder grids/arrows around them so that they are easier to find. Further, the manufacturing process was changed from e‐beam lithography to a mask process to be able to offer the test material at a favourable price. The use of masks also had to be adapted for the new manufacturing process so that the smallest square structures are also realised as such and do not show any distortion of the structure boundaries. The quality control using a metrological SEM confirmed a very reproducible manufacturing process. It is demonstrated that the test material can be successfully employed to find the most suitable beam size of the XPS system used for the analysis of small (μm range) surface features.
KW - Small-area measurements
KW - Test material
KW - XPS
KW - XPS imaging
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616577
DO - https://doi.org/10.1002/sia.7367
SP - 1
EP - 6
PB - Wiley
AN - OPUS4-61657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wasmer, Paul
A1 - Bulling, Jannis
A1 - Gravenkamp, H.
A1 - Prager, Jens
T1 - Acoustic-structure interaction in the Scaled Boundary Finite Element Method for primsatic geometries
N2 - Due to the short wavelength compared to the dimensions of the structure, the simulation of ultrasonic waves is still a challenging task. A numerical method well suited for this purpose is the semi-analytical Scaled Boundary Finite Element Method (SBFEM). When applying this method, only the boundary of a computational domain is discretized using finite elements, while the interior is described by an analytical ansatz. Hence, the number of degrees of freedom is reduced significantly compared to the classical Finite Element Method (FEM).
In recent years, a particular formulation of the SBFEM for the simulation of ultrasonic guided waves was developed. The method constitutes an efficient algorithm for prismatic structures of arbitrary length, such as plates, pipes, or beams. Wave propagation phenomena in such structures can be modeled for isotropic and anisotropic inhomogeneous waveguides. Even though the method is an efficient tool for the simulation of guided waves in solid media, a reliable model for the simulation of acoustic wave propagation in fluids as well as acoustic-structure interaction in terms of SBFEM is still missing. In principle, the fluid can be described by a displacement-based formulation and thus be implemented in existing SBFEM algorithms for solid bodies. However, due to the discretization with classical finite elements, spurious modes occur, which cannot be separated from the physical modes straightforwardly. The spurious modes can be suppressed using a penalty parameter. Although very accurate results were achieved for some problems, this procedure has been proven unreliable for certain cases.
For this reason, we propose a different approach in this contribution. We employ a pressure model to simulate the acoustic behavior of fluids. The implementation of the pressure model results in a higher effort due to the necessity of incorporating coupling terms, but it presents a stable alternative without spurious modes. The accuracy of the method is demonstrated in comparison with analytical solutions and results obtained using the FEM.
T2 - GACM 2019
CY - Kassel, Germany
DA - 28.08.2019
KW - Scaled Boundary Finite Element Method
KW - Guided Waves
KW - Ultrasound
KW - Acoustic-Structure Interaction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497364
UR - https://www.upress.uni-kassel.de/katalog/abstract.php?978-3-7376-5093-9
SN - 978-3-86219-5093-9
DO - https://doi.org/10.19211/KUP9783737650939
SP - 347
EP - 350
AN - OPUS4-49736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Boehm, Rainer
T1 - Phased Array und Imaging, zwei raumzeitliche Interferenzverfahren
N2 - Phased-Array-Technik und Bildgebung mit Ultraschallwellen sind nach langer Entwicklungszeit inzwischen auf dem Weg zu allgemeiner Verbreitung. Daher bietet sich an, die verschiedenen Techniken und deren Begriffe wie z.B. Phased-Array, SAFT, TFM, FMC und Sparse-Array zusammenfassend in Beziehung zu setzen.
All diesen Techniken liegt dieselbe Idee zu Grunde, nämlich durch gezielte Überlagerung von Ultraschallsignalen den gewünschten Effekt zu erreichen. Die verschiedenen Techniken werden kurz charakterisiert und neben den Unterschieden wird beschreiben, auf welche Weise bei all diesen Techniken das Phänomen der konstruktiven Interferenz jeweils genutzt wird.
T2 - Ultraschall-Array-Technologien und ihre Anwendungen, Seminar des FA Ultraschallprüfung der DGZfP
CY - Berlin, Germany
DA - 04.11.2019
KW - Phased Array
KW - Imaging
KW - Synthetic Aperture Focusing Technique
KW - Total Focusing Methode
KW - Full Matrix Capture
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497924
UR - https://www.dgzfp.de/seminar/ultraschall#
SP - 1
EP - 20
PB - DGZfP
AN - OPUS4-49792
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nöller, Renate
A1 - Danielewski, A.
A1 - Giel, R.
A1 - Overgaauw, E.
A1 - Hahn, Oliver
T1 - Material analysis of Aztec codices in Berlin. Assignment of small fragments compiled as cutouts on one plate in Humboldt’s “Atlas pittoresque du voyage”
N2 - The collection Manuscripta Americana in Berlin consists of fragmented codices acquired by Alexander von Humboldt in Mexico. Some of these Humboldt Codices are published as hieroglyphic writings of the Aztecs in “Vues des Cordilleres et Monuments des Peuples indigènes de l’Amerique”. Starting from a special compilation of seven fragments on plate 36 in the “Atlas”, we investigated the corresponding original fragments using material analysis in order to clarify their historical relations. The analyses were carried out with X-ray fluorescence analysis, VIS spectroscopy, and infrared spectroscopy in diffuse reflection and revealed typical indigenous colors like cochineal, indigo, and organic yellows (e.g. mangrove and zacatlaxcalli). Four fragments under investigation show exactly the same material and thus must once have belonged together in one compendium. An additional manuscript from Mizquiahuala also shown on plate 36 can be matched to another one that is not published in the “Atlas”.
KW - Manuscripts
KW - Alexander von Humboldt
KW - Non-destructiv testing
KW - Colourants
KW - Writing materials
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498971
DO - https://doi.org/10.1080/20548923.2019.1682816
SN - 2054-8923
SP - 1
EP - 14
PB - Routledge, Taylor & Francis Group
CY - London
AN - OPUS4-49897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Greco, A.
A1 - Starostin, V.
A1 - Karapanagiotis, Christos
A1 - Hinderhofer, A.
A1 - Gerlach, A.
A1 - Pithan, L.
A1 - Liehr, Sascha
A1 - Schreiber, Frank
A1 - Kowarik, Stefan
T1 - Fast fitting of reflectivity data of growing thin films using neural networks
N2 - X-ray reflectivity (XRR) is a powerful and popular scattering technique that can give valuable insight into the growth behavior of thin films. This study Shows how a simple artificial neural network model can be used to determine the thickness, roughness and density of thin films of different organic semiconductors [diindenoperylene, copper(II) phthalocyanine and alpha-sexithiophene] on silica from their XRR data with millisecond computation time and with minimal user input or a priori knowledge. For a large experimental data set of 372 XRR curves, it is shown that a simple fully connected model can provide good results with a mean absolute percentage error of 8–18% when compared with the results obtained by a genetic least mean squares fit using the classical Parratt formalism. Furthermore, current drawbacks and prospects for improvement are discussed.
KW - Artificial neural networks
KW - X-ray reflectivity
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498997
DO - https://doi.org/10.1107/S1600576719013311
SN - 1600-5767
VL - 52
SP - 1342
EP - 1347
PB - Wiley
AN - OPUS4-49899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bednarska, Dalia
A1 - Wieczorek, Alicja
A1 - von Werder, Julia
T1 - A novel methodology for indirect application of hydrophobic agents into cement matrix: Superabsorbent polymers (SAPs) as a delivery medium
N2 - Hydrophobic agents are one of the most commonly used means of prolonging the lifespan of cement-based materials. However, when water-repellent is added to the batch water it can interfere with cement hydration leading to deteriorated mechanical properties of the hardened material. To eliminate this drawback, a novel methodology of indirectly applying hydrophobic agents to cement-based materials is introduced. The presented approach uses super absorbent polymers (SAPs) as a delivery medium. SAP containing water-repellent is added to the fresh cement mixture, which ensures a gradual release of the admixture. The release is driven either by drying which generates moisture gradient or by compression of polymer particles by hydrates arising in their vicinity. Such mechanisms lead to a delayed dosage of the hydrophobic agent, which is when the partially hardened cement matrix is less vulnerable to interference compared to the fresh mixture. The effectiveness of the proposed methodology was verified in the extensive experimental program. Cement mortars of two water-to-cement ratios (0.4, and 0.5) were tested in terms of compressive strength, capillary absorption, and contact angle among others. Based on the obtained results it is concluded that the proposed methodology limits the negative impact of the hydrophobic agent on cement hydration. The mechanical performance of the samples modified with the indirectly dosed admixture is improved compared to the conventionally hydrophobized material in each analysed case. The results of isothermal calorimetry support the thesis. Additionally, the effectiveness of imparting hydrophobic characteristics to the cement matrix was as good as in the case of the conventional dosing. The mercury intrusion porosimetry, as well as thermogravimetric tests, were run to provide a deeper insight into the microstructure and composition of the modified material. Scanning electron microscopy was used to give a better insight into samples’ morphology. The novel methodology presented can also potentially be used
to dose other types of admixtures that can interfere with cement hydration.
KW - Super absorbent polymers
KW - Cement mortar
KW - Hydrophobic admixture
KW - Hydrophobization
KW - Capillary absorption
KW - Thermal analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637701
DO - https://doi.org/10.1016/j.cscm.2025.e04935
SN - 2214-5095
VL - 23
SP - 1
EP - 23
PB - Elsevier Ltd.
AN - OPUS4-63770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Rades, Steffi
A1 - Salge, T.
A1 - Mielke, Johannes
A1 - Ortel, Erik
A1 - Schmidt, R.
T1 - Characterisation of nanoparticles by means of high-resolution SEM/EDS in transmission mode
N2 - Advances in scanning electron microscopy (SEM) enable the high-resolution imaging of single nanoparticles (NPs) with sizes well below 10 nm. The SEM analysis in transmission mode (T-SEM) of NPs on thin film supports has many benefits when compared to the analysis of NPs on bulk substrates. The enhanced material (mass – thickness) contrast of the T-SEM imaging mode is well suited for in-depth and, particularly valuable, to very accurate, traceable, lateral dimensional measurements of NPs. Compared to samples prepared on bulk substrates, T-SEM with energy dispersive X-ray spectroscopy (EDS) achieves a drastically improved spatial resolution of the emitted X-rays. The poor signal-to-noise ratio of the X-ray spectra emitted by a single nanoparticle (NP) can be improved by the use of high-sensitivity (high collection solid angle) silicon drift (SDD), energy-dispersive X-ray spectrometers (EDS). The EDS spectral imaging of a single NP with a spatial resolution below 10 nm has become possible. This is demonstrated by means of various examples of nanostructures. Advanced data processing of T-SEM/EDS results sets the stage for the automated classification of NPs by feature analysis. This method combines the detection of morphological structures of interest by image processing of T-SEM micrographs with the chemical classification by EDS.
T2 - European Microbeam Analysis Society’s 14th European Workshop on Modern Developments and Applications in Microbeam Analysis (EMAS 2015)
CY - Portorož, Slovenia
DA - 03.05.2015
KW - High-resolution
KW - SEM
KW - T-SEM
KW - EDX
KW - Nanoparticles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355628
UR - http://iopscience.iop.org/article/10.1088/1757-899X/109/1/012006
DO - https://doi.org/10.1088/1757-899X/109/1/012006
SN - 1757-899X
VL - 109
SP - 012006-1
EP - 012006-12
PB - IOP Publishing Ltd
CY - Bristol, UK
AN - OPUS4-35562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Rades, Steffi
A1 - Borghetti, P.
A1 - Ortel, Erik
A1 - Wirth, Thomas
A1 - Garcia, S.
A1 - Gómez, E.
A1 - Blanco, M.
A1 - Alberto, G.
A1 - Martra, G.
T1 - Organic surface modification and analysis of titania nanoparticles for self‐assembly in multiple layers
N2 - The characteristics of TiO2 coatings can greatly influence their final performance in large‐scale applications. In the present study, self‐assembly of TiO2 nanoparticles (NPs) in multiple layers was selected as a deposition procedure on various substrates. For this, the main prerequisite constitutes the surface modification of both NPs and substrate with, for example, silane coupling agents. A set of functionalized TiO2 NPs has been produced by reaction with either (3‐aminopropyl)triethoxysilane (APTES) or (3‐aminopropyl)phosphonic acid (APPA) to functionalize the NP surface with free amino‐groups. Then, the complementary functionalized NP set can be obtained from an aliquot of the first one, through the conversion of free surface amino groups to aldehydes by reaction with glutaraldehyde (GA). Several types of TiO2 NPs differing in size, shape, and specific surface area have been functionalized. Fourier‐transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), SEM/ energy‐dispersive X‐ray spectroscopy (EDS), XPS, Auger electron spectroscopy (AES), and Time‐of‐Flight (ToF)‐SIMS analyses have been carried out to evaluate the degree of functionalization, all the analytical methods employed demonstrating successful functionalization of TiO2 NP surface with APTES or APPA and GA.
KW - TiO2
KW - Nanoparticles
KW - Surface functionalization
KW - Layer-by-layer deposition
KW - Surface chemical analysis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508601
DO - https://doi.org/10.1002/sia.6842
SN - 1096-9918
VL - 52
IS - 12
SP - 829
EP - 834
PB - John Wiley & Sons Ltd
AN - OPUS4-50860
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Erroneous or Arrhenius: A Degradation Rate-Based Model for EPDM during Homogeneous Ageing
N2 - To improve the predictive capability of long-term stress relaxation of elastomers during thermo-oxidative ageing, a method to separate reversible and irreversible processes was adopted.
The separation is performed through the analysis of compression set after tempering. On the Basis of this separation, a numerical model for long-term stress relaxation during homogeneous ageing is proposed. The model consists of an additive contribution of physical and chemical relaxation.
Computer simulations of compression stress relaxation were performed for long ageing times and the results were validated with the Arrhenius treatment, the kinetic study and the time-temperature superposition technique based on experimental data. For chemical relaxation, two decay functions are introduced each with an activation energy and a degradative process. The first process with the lower activation energy dominates at lower ageing times, while the second one with the higher activation energy at longer ageing times. A degradation-rate based model for the evolution of each process and ist contribution to the total system during homogeneous ageing is proposed. The main advantage of the model is the possibility to quickly validate the interpolation at lower temperatures within the range of slower chemical processes without forcing a straight-line extrapolation.
KW - Kinetic study
KW - Arrhenius
KW - TTS
KW - Modeling
KW - Chemical processes
KW - Stress relaxation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512931
DO - https://doi.org/10.3390/polym12092152
SN - 2073-4360
VL - 12
IS - 9
SP - 1
EP - 21
AN - OPUS4-51293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, R.
A1 - Elbers, I.
A1 - Undas, A.
A1 - Sijtsma, E.
A1 - Briffa, S.
A1 - Carnell-Morris, P.
A1 - Siupa, A.
A1 - Yoon, T.-H.
A1 - Burr, L.
A1 - Schmid, D.
A1 - Tentschert, J.
A1 - Hachenberger, Y.
A1 - Jungnickel, H.
A1 - Luch, A.
A1 - Meier, F.
A1 - Kocic, J.
A1 - Kim, J.
A1 - Park, B. C.
A1 - Hardy, B.
A1 - Johnston, C.
A1 - Jurkschat, K.
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Lynch, I.
A1 - Valsami-Jones, E.
T1 - Benchmarking the ACEnano toolbox for characterisation of nanoparticle size and concentration by interlaboratory comparisons
N2 - ACEnano is an EU-funded project which aims at developing, optimising and validating methods for the detection and characterisation of nanomaterials (NMs) in increasingly complex matrices to improve confidence in the results and support their use in regulation. Within this project, several interlaboratory comparisons (ILCs) for the determination of particle size and concentration have been organised to benchmark existing analytical methods. In this paper the results of a number of these ILCs for the characterisation of NMs are presented and discussed. The results of the analyses of pristine well-defined particles such as 60 nm Au NMs in a simple aqueous suspension showed that laboratories are well capable of determining the sizes of these particles. The analysis of particles in complex matrices or formulations such as consumer products resulted in larger variations in particle sizes within technologies and clear differences in capability between techniques. Sunscreen lotion sample analysis by laboratories using spICP-MS and TEM/SEM identified and confirmed the TiO2 particles as being nanoscale and compliant with the EU definition of an NM for regulatory purposes. In a toothpaste sample orthogonal results by PTA, spICP-MS and TEM/SEM agreed and stated the TiO2 particles as not fitting the EU definition of an NM. In general, from the results of these ILCs we conclude that laboratories are well capable of determining particle sizes of NM, even in fairly complex formulations.
KW - Nanomaterials
KW - Benchmarking
KW - Inter-laboratory comparison
KW - ACEnano
KW - Characterisation
KW - Size
KW - Concentration
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531852
DO - https://doi.org/10.3390/molecules26175315
SN - 1420-3049
VL - 26
IS - 17
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-53185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cosimi, Andrea
A1 - Stöbener, Daniel D.
A1 - Nickl, Philip
A1 - Schusterbauer, Robert
A1 - Donskyi, Ievgen
A1 - Weinhart, Marie
T1 - Interfacial nanoengineering of hydrogel surfaces via block copolymer self-assembly
N2 - Synthetic polymer hydrogels are valuable matrices for biotransformations, drug delivery, and soft implants. While the bulk properties of hydrogels depend on chemical composition and network structure, the critical role of interfacial features is often underestimated. This work presents a nanoscale modification of the gel−water interface using polymer brushes via a straightforward “grafting-to” strategy, offering an alternative to more cumbersome “grafting-from” approaches. Functional block copolymers with photoreactive anchor blocks are successfully self-assembled and UV-immobilized on hydrogel substrates despite their low solid content (<30 wt %). This versatile technique works on both bulk- and surface-immobilized hydrogels, demonstrated on poly(hydroxypropyl acrylate), poly(N-isopropylacrylamide), and alginate gels, allowing precise control over grafting density. X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry revealed a homogeneous bilayered architecture. By “brushing-up”, the hydrogels’ interface can be tailored to enhance protein adsorption, improve cell adhesion, or impair the diffusive uptake of small molecules into the bulk gels. This effective interfacial nanoengineering method is broadly applicable for enhancing hydrogel performance across a wide range of applications.
KW - Brushing-up
KW - Benzophenone
KW - LCTS-type polymer
KW - Poly(glycidyl ether) (PGE)
KW - Fibroblast adhesion
KW - XPS
KW - ToF-SIMS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652966
DO - https://doi.org/10.1021/acsami.4c18632
SN - 1944-8244
VL - 17
IS - 6
SP - 10073
EP - 10086
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-65296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Sparnacci, K.
A1 - Unger, Wolfgang
A1 - Tougaard, S.
T1 - Determining nonuniformities of core-shell nanoparticle coatings by analysis of the inelastic background of X-ray photoelectron spectroscopy survey spectra
N2 - Most real core-shell nanoparticle (CSNP) samples deviate from an ideal core-shell structure potentially having significant impact on the particle properties. An ideal structure displays a spherical core fully encapsulated by a shell of homogeneous thickness, and all particles in the sample exhibit the same shell thickness. Therefore,
analytical techniques are required that can identify and characterize such deviations.
This study demonstrates that by analysis of the inelastic background in X-ray photoelectron spectroscopy (XPS) survey spectra, the following types of deviations can be identified and quantified: the nonuniformity of the shell thickness within a nanoparticle sample and the incomplete encapsulation of the cores by the shell material. Furthermore, CSNP shell thicknesses and relative coverages can be obtained. These results allow for a quick and straightforward comparison between several batches of a specific CSNP, different coating approaches, and so forth. The presented XPS methodology requires a submonolayer distribution of CSNPs on a substrate.
Poly(tetrafluoroethylene)-poly(methyl methacrylate) and poly(tetrafluoroethylene)-polystyrene polymer CSNPs serve as model systems to demonstrate the applicability of the approach.
KW - Core-shell
KW - Nanoparticles
KW - Inelastic background
KW - Polymers
KW - QUASES
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511315
DO - https://doi.org/10.1002/sia.6865
SN - 0142-2421
SN - 1096-9918
VL - 52
SP - 1
EP - 8
PB - Wiley
CY - Chichester
AN - OPUS4-51131
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mieller, Björn
A1 - Vogl, Jochen
A1 - Noordmann, J.
A1 - Kaltenbach, A.
A1 - Rienitz, O.
T1 - Preparation and characterization of primary magnesium mixtures for the ab initio calibration of absolute magnesium isotope ratio measurements
N2 - We report an appropriate preparation of binary isotope calibration mixtures of the three stable isotopes of magnesium to be used in the ab initio calibration of multicollector mass spectrometers (ICPMS and TIMS). For each of the three possible combinations of binary mixtures ("24Mg" + "25Mg", "24Mg" + "26Mg", and "25Mg" + "26Mg"), three individual setups have been prepared under gravimetric control, each of them with an isotope ratio close to unity, and a total magnesium mass fraction close to 20 mg kg-1. The preparation was designed to occur via an intermediate dilution of a parent solution of a highly purified specimen of the isotopically enriched magnesium materials. For the application as calibration mixtures, a complete uncertainty budget was set up, and is presented and discussed in detail, including the aspects that went into the design of the dilution and mixing approach to minimize uncertainty. The principle parameters for the purpose of the later calibration of the mass spectrometers are the absolute masses of isotopically enriched magnesium materials in the primary calibration mixtures. For the first time relative expanded uncertainties U (k = 2) for these masses of ≤0.005% could be achieved for all mixtures.
KW - Atomic weight
KW - Magnesium
KW - Isotope mixture
KW - Purity
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-352564
DO - https://doi.org/10.1039/c5ja00284b
SN - 0267-9477
SN - 1364-5544
N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B.
N1 - Corrigendum: Journal of analytical atomic spectrometry 34 (2019) 2340
VL - 31
IS - 1
SP - 179
EP - 196
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-35256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogl, Jochen
A1 - Mieller, Björn
A1 - Noordmann, J.
A1 - Rienitz, O.
A1 - Malinovskiy, D.
T1 - Characterization of a series of absolute isotope reference materials for magnesium: ab initio calibration of the mass spectrometers, and determination of isotopic compositions and relative atomic weights
N2 - For the first time, an ab initio calibration for absolute Mg isotope ratios was carried out, without making any a priori assumptions. All quantities influencing the calibration such as the purity of the enriched isotopes or liquid and solid densities were carefully analysed and their associated uncertainties were considered. A second unique aspect was the preparation of three sets of calibration solutions, which were applied to calibrate three multicollector ICPMS instruments by quantifying the correction factors for instrumental mass discrimination. Those fully calibrated mass spectrometers were then used to determine the absolute Mg isotope ratios in three candidate European Reference Materials (ERM)-AE143, -AE144 and -AE145, with ERM-AE143 becoming the new primary isotopic reference material for absolute isotope ratio and delta measurements. The isotope amount ratios of ERM-AE143 are n(25Mg)/n(24Mg) = 0.126590(20) mol/mol and n(26Mg)/n(24Mg) = 0.139362(43) mol/mol, with the resulting isotope amount fractions of x(24Mg) = 0.789920(46) mol/mol, x(25Mg) = 0.099996(14) mol/ mol and x(26Mg) = 0.110085(28) mol/mol and an atomic weight of Ar(Mg) = 24.305017(73); all uncertainties were stated for k = 2. This isotopic composition is identical within uncertainties to those stated on the NIST SRM 980 certificate. The candidate materials ERM-AE144 and -AE145 are isotopically lighter than ERM-AE143 by 1.6 ‰ and 1.3 ‰, respectively, concerning their n(26Mg)/n(24Mg) ratio. The relative combined standard uncertainties are ≤0.1 ‰ for the isotope ratio n(25Mg)/n(24Mg) and ≤0.15 ‰ for the isotope ratio n(26Mg)/ n(24Mg). In addition to characterizing the new isotopic reference materials, it was demonstrated that commonly used fractionation laws are invalid for correcting Mg isotope ratios in multicollector ICPMS as they result in a bias which is not covered by its associated uncertainty. Depending on their type, fractionation laws create a bias up to several per mil, with the exponential law showing the smallest bias between 0.1 ‰ and 0.7 ‰.
KW - isotope reference material
KW - absolute measurements
KW - mass spectrometry
KW - atomic weight
KW - magnesium
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370931
DO - https://doi.org/10.1039/C6JA00013D
SN - 0267-9477
N1 - Geburtsname von Mieller, Björn: Brandt, B. - Birth name of Mieller, Björn: Brandt, B.
VL - 31
IS - 7
SP - 1440
EP - 1458
PB - Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-37093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Jaenisch, Gerd-Rüdiger
A1 - Kardjilov, N.
A1 - Tötzke, C.
A1 - Markötter, Henning
A1 - Hilger, A.
A1 - Manke, I.
T1 - Compton-CT als Alternative zur Neutronentomographie?
N2 - Als Alternative zur Neutronentomographie wird das Potenzial der Computertomographie (CT) mit inkohärenter Röntgen-Streustrahlung (Compton-Streuung) untersucht. Die gleichzeitige Abbildung von Materialien sehr unterschiedlicher Dichten (Ordnungszahlen) ist eine wiederkehrende Herausforderung für die Radiologie und die Computertomographie mit Röntgenstrahlung. Die Messungen ergeben asymmetrische Projektionsprofile für Sinogramme der Streuintensität. Am Beispiel verschiedener Polymere (Polyethylen, Polyamid, PVC), Glas und Holz wird in den Tomogrammen ein hochaufgelöster 'Comptonkontrast' vergleichbarer Dynamik erreicht, während der simultan gemessene 'Absorptionskontrast' ausschließlich die starken Absorber (Glas und PVC) zeigt. Der Vergleich mit ähnlich auflösender Neutronentomographie zeigt ähnliche Kontraste und eröffnet mithin die Möglichkeit, diese künftig durch Compton-Tomographie im Labormaßstab zu ersetzen.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Comptonstreuung
KW - Computertomographie
KW - Neutronentomographie
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-342894
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Mo.3.A.2, 1
EP - 10
AN - OPUS4-34289
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Hentschel, M. P.
A1 - Lange, A.
A1 - Trappe, Volker
A1 - Laquai, René
A1 - Shashev, Yury
A1 - Evsevleev, Sergei
A1 - Bruno, Giovanni
T1 - Progress survey of X-Ray refraction imaging techniques
N2 - The most substantial innovations in radiographic imaging techniques of the last two decades aim at enhanced image contrast of weakly absorbing micro and nano structures by taking advantage of X-ray refraction effects occurring at outer and inner surfaces. The applications range from fibre reinforced plastics to biological tissues. These techniques comprise, among others, X-ray refraction topography, diffraction enhanced imaging, phase contrast imaging, Talbot-Lau grating interferometry, and refraction enhanced imaging. They all make use of selective beam deflections up to a few minutes of arc: the X-ray refraction effect. In contrast to diffraction, this type of interaction has a 100 % scattering cross section, as shown experimentally. Since X-ray refraction is very sensitive to the orientation of interfaces, it is additionally a tool to detect, e.g., fibre or pore orientation. If the detector resolution exceeds the size of (small) individual features, one detects the integral information (of inner surfaces) within the gauge volume. We describe the above-mentioned techniques, and show their experimental implementation in the lab and at a synchrotron source. We also show strategies for data processing and quantitative analysis.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - grating
KW - topography
KW - refraction
KW - X-ray
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366194
SN - 978-3-940283-78-8
VL - 2016/158
SP - We.3.B.2, 1
EP - 9
AN - OPUS4-36619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Laquai, René
A1 - Schaupp, Thomas
A1 - Müller, Bernd R.
A1 - Griesche, Axel
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Kannengießer, Thomas
A1 - Bruno, Giovanni
T1 - 3D Crack analysis in hydrogen charged lean duplex stainless steel with synchrotron refraction CT
N2 - Hydrogen in metals can cause a degradation of the mechanical properties, the so-called hydrogen embrittlement. In combination with internal stresses, hydrogen assisted cracking (HAC) can occur. This phenomenon is not completely understood yet. To better characterise the cracking behaviour, it is important to gain information about the evolution of the 3D crack network. For this purpose samples of lean duplex stainless steel were loaded with hydrogen by means of electrochemical charging and investigated by means of synchrotron refraction CT and SEM fractography after uniaxial tensile loading. Synchrotron refraction CT is an analyser-based imaging (ABI) technique. It uses a Si (111) single crystal as analyser, which is placed into the beam path between sample and detector. According to Bragg’s law only incident x-rays within a narrow range around the Bragg-angle are diffracted from the analyser into the detector. Hence, the analyser acts as an angular filter for the transmitted beam. This filtering allows to turn the refraction and scattering of x-rays into image contrast. Refraction occurs at all interfaces, where the density of the material changes and is more sensitive to density changes than the attenuation. Therefore, it is possible to detect smaller cracks than with classical x-ray imaging techniques, like CT, with comparable spacial resolution. It also visualises the 3D structure of the cracks and gains quantitative information about their morphology and distribution. Since cracks introduced by HAC are usually very small and have a small opening displacement, synchrotron refraction CT is expected to be well suited for imaging this cracking mechanism and can be a valuable tool to characterise the formation and the evolution of a 3D crack network.
T2 - WCNDT 2016
CY - München, Germany
DA - 13.06.2016
KW - X-ray refraction
KW - Computed tomography
KW - Hydrogen assisted cracking
KW - Duplex stainless steel
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366481
SN - 978-3-940283-78-8
VL - BB 158
SP - Tu.4.B.3, 1
EP - 9
AN - OPUS4-36648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Hentschel, Manfred P.
A1 - Lange, Axel
A1 - Bruno, Giovanni
A1 - Müller, Bernd R.
T1 - Direkte Röntgenrefraktion an Mikrostrukturen
N2 - Die durch Brechung an Mikrostrukturen abgelenkte Röntgenstrahlung wird direkt zweidimensional abgebildet. Dazu werden Modellproben einfacher Geometrie (Fasern, Kapillaren, monodisperse Nano- und Mikropartikel) mit einem auf 50 µm kollimierten Synchrotronstrahl (20 keV) gescannt. Die nach den Regeln der geometrischen Optik an prismatischen und linsenartigen Grenzflächen abgelenkte Strahlung wird in etwa 3 Metern Entfernung von einem Flächendetektor mit 7 µm Ortsauflösung zusätzlich zu der ungestörten Resttransmission des Primärstrahls registriert. In der Abfolge der Radiogramme werden die lokalen Orientierungsänderungen der Probekörper-Grenzflächen bei deren Abtastung mit wenigen Mikrometern Schrittweite bildhaft verfolgt. Mit der hier erreichten Winkelauflösung von etwa 3 Bogensekunden (Streuvektor-Inkremente Δk = 10-3nm-1) kann bei 50 µm Ortsauflösung das Materialvolumen bezüglich innerer Grenzflächen mit Nanometer-Separation auch bei hohen Abtastraten unterhalb einer Sekunde pro Bild charakterisiert werden.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Computertomographie (CT)
KW - Rekonstruktionsalgorithmus
KW - DIRECTT
KW - Missing wedge
KW - Statistische Bewertung
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312931
UR - http://www.ndt.net/article/dgzfp2014/papers/di1b2.pdf
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Di.1.B.2, 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31293
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cabeza, Sandra
A1 - Bruno, Giovanni
A1 - Mishurova, Tatiana
T1 - Characterization of multiphase metal matrix composites by means of CT and neutron diffraction
N2 - The present study examines the relationship between the microstructure of multiphase metal matrix composites and their damage mechanisms. The matrix AlSi12CuMgNi was combined with 15% vol. Al₂O₃ (short fibers), and with 7% vol. Al₂O₃ + 15% vol. SiC (short fibers and whiskers, respectively). The experimental approach encompasses 3D microstructure characterization by means of computed tomography of samples (a) as-cast, (b) after heat treatment, and (c) after compression tests at room temperature. The volume fraction of different phases, their distribution, their orientation, and the presence of defects and damage are studied.
The influence of the addition of SiC particles on mechanical properties of composite was investigated. Phase-specific load partition analysis for samples with fiber plane parallel to load was performed by using neutron diffraction (ND) during in-situ compression. ND results show damage in the Si phase, while Al₂O₃ short fibers carry load without damage until failure. The computed tomography observations confirm the load partition analysis.
T2 - WCNDT
CY - München, Germany
DA - 13.06.2016
KW - thermal treatment
KW - synchrotron CT
KW - neutron diffraction
KW - composite
KW - aluminum
KW - residual stress
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365499
AN - OPUS4-36549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shashev, Yury
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Britzke, Ralf
A1 - Bruno, Giovanni
A1 - Mueller, Bernd R.
A1 - Hentschel, Manfred P.
T1 - Talbot- Lau interferometry with a non- binary phase grating for non-destructive testing
N2 - Grating interferometric set-ups have been established in the last decade. They are promising candidates to obtain enhanced image contrast from weakly absorbing micro and nano structures. They are based on X-ray refraction and near-field diffraction using the Talbot effect.
At the expense of taking multiple images, Talbot-Lau grating interferometry allows separating the absorption, refraction, and scattering contributions by analysing the disturbances of a phase grating interference pattern. Contrary to other refraction enhanced methods, this technique can be applied using conventional X-ray tubes (divergent, polychromatic source). This makes it attractive to solve typical non-destructive testing problems.
We investigated the efficiency of phase gratings, i.e. the visibility (the amplitude of oscillations) upon variation of propagation distance and phase grating rotation around an axis parallel to the grid lines. This grating rotation changes the grating shape (i.e. the distributions of phase shifts). This can yield higher visibilities than derived from rectangular shapes.
Our study includes experimental results obtained from synchrotron radiation, as well as simulations for monochromatic radiation. The advantages of Talbot-Lau interferometry are demonstrated at the example of glass capillaries.
T2 - WCNDT2016
CY - Munich, Germany
DA - 13.06.2016
KW - Phase-contrast X-ray imaging
KW - Talbot- Lau interferometry
KW - Phase grating
KW - Visibility
KW - Synchrotron radiation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365987
SN - 978-3-940283-78-8
VL - BB 158
SP - Tu.3.G.2., 1
EP - 9
AN - OPUS4-36598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Cabeza, Sandra
A1 - Artzt, Katia
A1 - Haubrich, J.
A1 - Klaus, M.
A1 - Genzel, Ch.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - An Assessment of Subsurface Residual Stress Analysis in SLM Ti-6Al-4V
N2 - Ti-6Al-4V bridges were additively fabricated by selective laser melting (SLM) under different scanning speed conditions, to compare the effect of process energy density on the residual stress state. Subsurface lattice strain characterization was conducted by means of synchrotron diffraction in energy dispersive mode. High tensile strain gradients were found at the frontal surface for samples in an as-built condition. The geometry of the samples promotes increasing strains towards the pillar of the bridges. We observed that the higher the laser energy density during fabrication, the lower the lattice strains. A relief of lattice strains takes place after heat treatment.
KW - Selective laser melting
KW - Additive manufacturing
KW - Heat treatment
KW - Ti-6Al-4V
KW - Synchrotron X-ray diffraction
KW - Residual stress
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395759
DO - https://doi.org/10.3390/ma10040348
SN - 1996-1944
VL - 10
IS - 4
SP - Article 348, 1
EP - 14
AN - OPUS4-39575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obaton, A-F.
A1 - Fain, J.
A1 - Djemaï, M.
A1 - Meinel, Dietmar
A1 - Léonard, Fabien
A1 - Mahé, E.
A1 - Lécuelle, B.
A1 - Fouchet, J-J.
A1 - Bruno, Giovanni
T1 - In vivo XCT bone characterization of lattice structured implants fabricated by additive manufacturing
N2 - Several cylindrical specimens and dental implants, presenting diagonal lattice structures with different cell sizes (600, 900 and 1200 µm) were additively manufactured by selective laser melting process. Then they were implanted for two months in a sheep. After removal, they were studied by Archimedes’ method as well as X-ray computed tomography in order to assess the penetration of bone into the lattice. We observed that the additive manufactured parts were geometrically conform to the theoretical specifications. However, several particles were left adhering to the surface of the lattice, thereby partly or entirely obstructing the cells. Nevertheless, bone penetration was clearly visible. We conclude that the 900 µm lattice cell size is more favourable to bone penetration than the 1200 µm lattice cell size, as the bone penetration is 84 % for 900 µm against 54 % for 1200 µm cell structures. The lower bone penetration value for the 1200 µm lattice cell could possibly be attributed to the short residence time in the sheep. Our results lead to the conclusion that lattice implants additively manufactured by selective laser melting enable better bone integration.
KW - Biomedical engineering
KW - Dentistry
KW - Medical imaging
KW - X-ray computer tomography
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418648
DO - https://doi.org/10.1016/j.heliyon.2017.e00374
SN - 2405-8440
IS - 3
SP - Article e00374, 1
EP - 21
PB - Elsevier Limited
CY - 125 London Wall London, EC2Y 5AS United Kingdom
AN - OPUS4-41864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shashev, Yury
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Evsevleev, Sergei
A1 - Britzke, Ralf
A1 - Bruno, Giovanni
A1 - Müller, Bernd R.
T1 - Talbot-Lau Röntgen-Interferometrie für die zerstörungsfreie Prüfung
N2 - Im vergangenen Jahrzehnt sind gitterinterferometrische Röntgenabbildungen zunehmend in den Fokus des Interesses gerückt. Sie sind insbesondere dann Vorteil, wenn der in der Standardradiographie erreichbare Kontrast nicht genügt, schwach absorbierende Mikro- und Nanostrukturen abzubilden.
Auf Kosten mehrerer Aufnahmen gestattet die Talbot-Lau Gitterinterferometrie, die Beiträge aus Absorption, Refraktion und (refraktiver) Streuung zu trennen. Dazu werden die Störungen der Interferenzmuster von Phasengittern ausgewertet. Im Gegensatz zu einer Vielzahl anderer refraktionsbasierter Abbildungsmethoden kann diese Technik mit konventionellen Röntgenröhren (mit divergenter, polychromatischer Strahlung) angewendet werden. Damit ist die Technik geeignet, typische ZfP-Fragestellungen zu lösen.
Hier stellen wir Untersuchungen zur Effizienz von Phasengittern vor. Die Visibilität (d.h. die Höhe der Oszillation im Interferenzmuster) wird als Funktion verschiedener geometrischer Parameter verfolgt. Eine Rotation um die Achse parallel zu den Gitterstegen ändert die Form des Gitterprofils (d.h. die Verteilung der Phasenschiebungen). Die kontinuierliche Variation des Winkels und des Detektionsabstandes führt zur Identifikation von ausgezeichneten Kombinationen mit maximaler Visibilität, wobei die Abstände deutlich geringer sind als im Standardaufbau mit senkrechter Gitterbestrahlung.
Unsere Studie umfasst Simulationen für monochromatische Quelle und den Vergleich zu experimentellen Ergebnissen mit der Synchrotronstrahlung.
In der Literatur wurden die Vorteile der Talbot-Lau Interferometrie für die zerstörungsfreie Prüfung von Faserkompositen und Verbundwerkstoffen demonstriert. Hier werden als Beispiele Messungen an Aluminiumtitanat (Al2TiO5) Pulver gezeigt.
T2 - DGZfP 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Gitterinterferometrische Röntgenabbildung
KW - Phasengitter
KW - Talbot-Lau Interferometrie
KW - Zerstörungsfreie Prüfung
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404691
SP - 1
EP - 10
PB - DGZfP
AN - OPUS4-40469
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Kasperovich, G.
A1 - Haubrich, J.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - X-ray refraction distinguishes unprocessed powder from empty pores in selective laser melting Ti-6Al-4V
N2 - For the first time, X-ray refraction techniques are proven for the identification of void formation in Ti-6Al-4V parts produced by selective laser melting. The topology and volume fraction of pores are measured in samples produced with different laser energy density. Unique X-ray refraction methods identify different kinds of defects, characteristic to the regions below and above the Optimum laser energy density, namely unprocessed powder (unmolten powder particles, balling effect, and Fusion defects) from empty keyhole pores. Furthermore, it is possible to detect small inhomogeneities (voids or cracks) with sizes below the spatial resolution of optical microscopy and X-ray computed tomography.
KW - Additive manufacturing
KW - X-ray refraction
KW - Microscopy
KW - X-ray computed tomography
KW - Porosity
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434041
DO - https://doi.org/10.1080/21663831.2017.1409288
SN - 2166-3831
VL - 6
IS - 2
SP - 130
EP - 135
PB - Taylor & Francis Group
CY - London, UK
AN - OPUS4-43404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Kasperovich, G.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Unterscheidung verschiedener charakteristischer Defekte in mittels selektivem Laserschmelzen hergestelltem Ti-6Al-4V durch Röntgen-Refraktionsradiographie
N2 - Das selektive Laserschmelzen (SLM) ist eine pulverbasierte, additive Fertigungsmethode, welche die Herstellung von komplex und individuell geformten Bauteilen ermöglicht. Im Laufe der vergangenen Jahre haben verschiedene Branchen, unter anderem die Luft- und Raumfahrt Industrie, begonnen diese Technologie intensiv zu erforschen. Insbesondere die Titanlegierung Ti-6Al-V4, welche aufgrund ihrer Kombination von mechanischen Eigenschaften, geringer Dichte und Korrosionsbeständigkeit häufig in der Luft- und Raumfahrt eingesetzt wird, eignet sich für die Herstellung mittels SLM. Allerdings können durch nicht optimal gewählte Prozessparameter, welche für gewöhnlich in einer Energiedichte zusammengefasst werden, Defekte in den Bauteilen entstehen.
In dieser Studie wurde untersucht, in wie weit Röntgen-Refraktionsradiographie geeignet ist diese Defekte zu detektieren und zu charakterisieren. Bei der Röntgen-Refraktionsradiographie wird die Röntgenstrahlung, nachdem sie die Probe transmittiert hat, über einen Analysatorkristall gemäß der Bragg-Bedingung in den 2D-Detektor reflektiert und dabei nach ihrer Ausbreitungsrichtung gefiltert. Dadurch wird neben der Schwächung auch die Ablenkung der Röntgenstrahlung durch Refraktion im inneren der Probe zur Bildgebung ausgenutzt. Aus den aufgenommen Refraktionsradiogrammen kann der Refraktionswert berechnet werden. Dieser ist ein Maß für die Menge an inneren Oberflächen in der Probe.
Zum einen konnte gezeigt werden, dass die Röntgen-Refraktionsradiographie Defekte detektieren kann, die kleiner sind als die Ortsauflösung des verwendeten 2D-Detektors. Zum anderen können zwei verschiedene Typen von Defekten unterschieden werden. Bei dem ersten Typ handelt es sich um runde Poren mit geringer innerer Oberfläche. Diese, sogenannten „keyhole pores“ sind charakteristisch für eine zu hohe Energiedichte während des SLM Prozesses. Bei dem zweiten Typ handelt es sich um nicht komplett aufgeschmolzenes Pulver. Diese Defekte zeichnen sich durch eine hohe innere Oberfläche aus und sind charakteristisch für eine zu geringe Energiedichte. Vergleichende Messungen mit hochauflösender Synchrotron CT und optischer Mikroskopie bestätigen die charakteristischen Formen der verschiedenen Defekte.
T2 - DGZfP-Jahrestagung 2018
CY - Leipzig, Germany
DA - 07.05.2018
KW - Röntgen-Refraktion
KW - Additive Fertigung
KW - Porosität
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-449524
SN - 978-3-940283-92-4
VL - DGZfP BB166
SP - Mo.2.A.2., 1
EP - 7
AN - OPUS4-44952
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Shashev, Yury
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Britzke, Ralf
A1 - Bruno, Giovanni
A1 - Müller, Bernd R.
A1 - Hentschel, M. P.
T1 - Talbot- Lau interferometry with a non- binary phase grating for non-destructive testing
N2 - Grating interferometric set-ups have been established in the last decade. They are promising candidates to obtain enhanced image contrast from weakly absorbing micro and nano structures. They are based on X-ray refraction and near-field diffraction using the Talbot effect.
At the expense of taking multiple images, Talbot-Lau grating interferometry allows separating the absorption, refraction, and scattering contributions by analysing the disturbances of a phase grating interference pattern. Contrary to other refraction enhanced methods, this technique can be applied using conventional X-ray tubes (divergent, polychromatic source). This makes it attractive to solve typical non-destructive testing problems.
We investigated the efficiency of phase gratings, i.e. the visibility (the amplitude of oscillations) upon variation of propagation distance and phase grating rotation around an axis parallel to the grid lines. This grating rotation changes the grating shape (i.e. the distributions of phase shifts). This can yield higher visibilities than derived from rectangular shapes.
Our study includes experimental results obtained from synchrotron radiation, as well as simulations for monochromatic radiation. The advantages of Talbot-Lau interferometry are demonstrated at the example of glass capillaries.
T2 - 19th World Conference on Non-Destructive Testing 2016
CY - Munich, Germany
DA - 13.06.2016
KW - Talbot- Lau interferometry
KW - Phase grating
KW - Non-destructive testing
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-383163
SP - Tu_3_G_2, 1
EP - 9
AN - OPUS4-38316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Johann, Sergej
A1 - Strangfeld, Christoph
A1 - Müller, Maximilian
A1 - Mieller, Björn
A1 - Bartholmai, Matthias
T1 - RFID sensor systems embedded in concrete – validation experiments for long-term monitoring
N2 - Structural Health Monitoring (SHM) is an important part of buildings surveillance and maintenance to detect material failure as early as possible and to contribute in protection of structures and their users.
The implementation of Radio Frequency Identification (RFID) sensor systems without cable connection and battery into building components offers innovative possibilities to enable long-term in-situ SHM of addressed structures, bridges. The objectives of the presented study are complete embedding of RFID sensors systems in concrete, full passive communication with the systems, at best for the whole life span of structures. One challenge for this task is the highly alkaline environment in concrete, which requires non-degrading and robust encapsulation. Further Requirements are passive communication and energy supply, appropriate antenna design, placement and fixation in concrete, and the selection and implementation of sensors and connections. The concept is to develop and optimize a simple and robust system, which meets the requirements, as well as comprehensive validation in concrete specimen and real world applications. Two different systems were developed (HF and UHF RFID, respectively).
First tasks were the implementation of analog sensors using the superposition principle for the signal adaption. Investigation of suitable materials for robust encapsulation and sensor protection against basic environments.
Four materials were investigated in pH 13 solution for 14 days
- 3D-Printer-Polymer was completely resolved
- PVC has no noticeable decrease in weight
- (VitaPro) glass filter for the sensor protector, has weight loss 2.7 %
- The epoxy resin has increased by 1.8 % due to moisture expansion
Different concrete samples were prepared for the validation of the systems.
RFID sensors were embedded in different integration depths. Investigate the energy- and data transfer through concrete, also with varying moisture content. Additionally, signal strength data was used to optimize and validate the antenna characteristics in concrete. Next steps are to guarantee a sufficient energy supply for UHF RFID systems embedded in different concrete mixtures and further embedding the HF and UHF RFID systems in real bridges and buildings to validate the long term monitoring.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Smart structures
KW - RFID sensors
KW - Long-term requirements
KW - Structural health monitoring
KW - Passive RFID
KW - Sensor requirements
KW - Sensors in concrete
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403496
UR - https://www.ndt.net/?id=21499
SN - 1435-4934
VL - 22
IS - 9
SP - 1
EP - 7
PB - NDT.net
CY - Kirchwald
AN - OPUS4-40349
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Johann, Sergej
A1 - Strangfeld, Christoph
A1 - Müller, Maximilian
A1 - Mieller, Björn
A1 - Bartholmai, Matthias
T1 - RFID sensor systems embedded in concrete – Validation experiments for long-term monitoring
T1 - RFID Sensorsysteme eingebettet in Beton – Validierungsexperimente
zum Langzeitmonitoring
N2 - Structural Health Monitoring (SHM) is an important part of buildings surveillance and maintenance to detect material failure as early as possible and to contribute in protection of structures and their users.
The implementation of Radio Frequency Identification (RFID) sensor systems without cable connection and battery into building components offers innovative possibilities to enable long-term in-situ SHM of addressed structures, bridges. The objectives of the presented study are complete embedding of RFID sensors systems in concrete, full passive communication with the systems, at best for the whole life span of structures. One challenge for this task is the highly alkaline environment in concrete, which requires non-degrading and robust encapsulation. Further Requirements are passive communication and energy supply, appropriate antenna design, placement and fixation in concrete, and the selection and implementation of sensors and connections. The concept is to develop and optimize a simple and robust system, which meets the requirements, as well as comprehensive validation in concrete specimen and real world applications. Two different systems were developed (HF and UHF RFID, respectively).
First tasks were the implementation of analog sensors using the superposition principle for the signal adaption. Investigation of suitable materials for robust encapsulation and sensor protection against basic environments.
Four materials were investigated in pH13 solution for 14 days - 3D-Printer-Polymer was completely resolved - PVC has no noticeable decrease in weight - (VitaPro) glass filter for the sensor protector, has weight loss 2.7% - The epoxy resin has increased by 1.8% due to moisture expansion Different concrete samples were prepared for the validation of the systems. RFID sensors were embedded in different integration depths. Investigate the energy- and data transfer through concrete, also with varying moisture content. Additionally, signal strength data was used to optimize and validate the antenna characteristics in concrete. Next steps are to guarantee a sufficient energy supply for UHF RFID systems embedded in different concrete mixtures and further embedding the HF and UHF RFID systems in real bridges and buildings to validate the long term monitoring.
KW - RFID sensors
KW - Structural health monitoring
KW - Sensors in concrete
KW - Smart structures
KW - Sensor requirements
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418331
UR - http://www.ndt.net/?id=21499
SN - 1435-4934
VL - 22
IS - 9
SP - Artikel 8, 1
EP - 7
PB - NDT.net
CY - Bad Breisig
AN - OPUS4-41833
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Trappe, Volker
A1 - Nielow, D.
A1 - Schumacher, David
A1 - Lange, A.
A1 - Hentschel, M.P.
A1 - Redmer, Bernhard
A1 - Ewert, U.
A1 - Bruno, Giovanni
T1 - X-ray laminographic inspection of sandwich shell segments for wind turbine rotor blades
N2 - 3D structural investigations are described by X-ray laminography studies of sandwich shell segments, made of a PVC foam core, covered by non-crimp fabric glass fibre composite lay-ups processed by vacuum assisted resin infusion of epoxy. The specific scope of this study is to image transversal flaws within the foam core (joints) and of single ply overlaps. Test flaws were purposely implemented in order to simulate typical failure under cyclic load. In a dedicated test rig for shell structures, the flaw evolution/propagation is monitored by thermography and optical 3D inspection of deformation. Due to the unfavourable preconditions for classical computed tomography as of large aspect ratio, the samples were investigated by coplanar translational laminography. Its limited range of observation angles of ± 45°, results in anisotropic artefacts about the normal to the sample surface, but the typical flaws are well visualized in the as-prepared state, in a state of early damage, and in the repaired state.
T2 - 12th European conference on Non-Destructive Testing
CY - Gothenburg, Sweden
DA - 11.06.2018
KW - X-ray laminography
KW - Wind turbine
KW - Rotor blade
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-453931
SN - 978-91-639-6217-2
SP - 1
EP - 8
AN - OPUS4-45393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buljak, V.
A1 - Oesch, Tyler
A1 - Bruno, Giovanni
T1 - Simulating fiber-reinforced concrete mechanical performance using CT-based fiber orientation data
N2 - The main hindrance to realistic models of fiber-reinforced concrete (FRC) is the local materials property variation, which does not yet reliably allow simulations at the structural level. The idea presented in this paper makes use of an existing constitutive model, but resolves the problem of localized material variation through X-ray computed tomography (CT)-based pre-processing. First, a three-point bending test of a notched beam is considered, where pre-test fiber orientations are measured using CT. A numerical model is then built with the zone subjected to progressive damage, modeled using an orthotropic damage model. To each of the finite elements within this zone, a local coordinate system is assigned, with its longitudinal direction defined by local fiber orientations. Second, the parameters of the constitutive damage model are determined through inverse analysis using load-displacement data obtained from the test. These parameters are considered to clearly explain the material behavior for any arbitrary external action and fiber orientation, for the same geometrical properties and volumetric ratio of fibers. Third, the effectiveness of the resulting model is demonstrated using a second, “control” experiment. The results of the “control” experiment analyzed in this research compare well with the model results. The ultimate strength was predicted with an error of about 6%, while the work-of-load was predicted within 4%. It demonstrates the potential of this method for accurately predicting the mechanical performance of FRC components.
KW - Fiber-reinforced concrete
KW - X-ray computed tomography (CT)
KW - Anisotropic fiber orientation
KW - Inverse analysis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474728
DO - https://doi.org/10.3390/ma12050717
SN - 1996-1944
VL - 12
IS - 5
SP - 717, 1
EP - 16
PB - MDPI
AN - OPUS4-47472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Artzt, K.
A1 - Haubrich, J.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Exploring the correlation between subsurface residual stresses and manufacturing parameters in laser powder bed fused Ti-6Al-4V
N2 - Subsurface residual stresses (RS) were investigated in Ti-6Al-4V cuboid samples by means of X-ray synchrotron diffraction. The samples were manufactured by laser powder bed fusion (LPBF) applying different processing parameters, not commonly considered in open literature, in order to assess their influence on RS state. While investigating the effect of process parameters used for the calculation of volumetric energy density (such as laser velocity, laser power and hatch distance), we observed that an increase of energy density led to a decrease of RS, although not to the same extent for every parameter variation. Additionally, the effect of support structure, sample roughness and LPBF machine effects potentially coming from Ar flow were studied. We observed no influence of support structure on subsurface RS while the orientation with respect to Ar flow showed to have an impact on RS.We conclude recommending monitoring such parameters to improve part reliability and reproducibility.
KW - Additive manufacturing
KW - Synchrotron X-ray diffraction
KW - Residual stress
KW - Ti-6Al-4V
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474281
DO - https://doi.org/10.3390/met9020261
SN - 2075-4701
VL - 9
IS - 2
SP - 261, 1
EP - 13
PB - MDPI
AN - OPUS4-47428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Gouraud, F.
A1 - Müller, Bernd R.
A1 - Huger, M.
A1 - Chotard, T.
A1 - Antou, G.
A1 - Bruno, Giovanni
T1 - Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures
N2 - Zirconia-based cast refractories are widely used for glass furnace applications. Since they have to withstand harsh chemical as well as thermo-mechanical environments, internal stresses and microcracking are often present in such materials under operating conditions (sometimes in excess of 1700 °C). We studied the evolution of thermal (CTE) and mechanical (Young’s modulus) properties as a function of temperature in a fused-cast refractory containing 94 wt.% of monoclinic ZrO2 and 6 wt.% of a silicate glassy phase. With the aid of X-ray refraction techniques (yielding the internal specific surface in materials), we also monitored the evolution of microcracking as a function of thermal cycles (crossing the martensitic phase transformation around 1000 °C) under externally applied stress. We found that external compressive stress leads to a strong decrease of the internal surface per unit volume, but a tensile load has a similar (though not so strong) effect. In agreement with existing literature on -eucryptite microcracked ceramics, we could explain These phenomena by microcrack closure in the load direction in the compression case, and by microcrack propagation (rather than microcrack nucleation) under tensile conditions.
KW - Electro-fused zirconia
KW - Microcracking
KW - Synchrotron x-ray refraction radiography (SXRR)
KW - Thermal expansion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477431
DO - https://doi.org/10.3390/ma12071017
VL - 12
IS - 7
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-47743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiede, Tobias
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Serrano-Munoz, Itziar
A1 - Gollwitzer, Christian
A1 - Bruno, Giovanni
T1 - 3D shape analysis of powder for laser beam melting by synchrotron X-ray CT
N2 - The quality of components made by laser beam melting (LBM) additive manufacturing is naturally influenced by the quality of the powder bed. A packing density <1 and porosity inside the powder particles lead to intrinsic voids in the powder bed. Since the packing density is determined by the particle size and shape distribution, the determination of these properties is of significant interest to assess the printing process. In this work, the size and shape distribution, the amount of the particle’s intrinsic porosity, as well as the packing density of micrometric powder used for LBM, have been investigated by means of synchrotron X-ray computed tomography (CT). Two different powder batches were investigated: Ti–6Al–4V produced by plasma atomization and stainless steel 316L produced by gas atomization. Plasma atomization particles were observed to be more spherical in terms of the mean anisotropy compared to particles produced by gas atomization. The two kinds of particles were comparable in size according to the equivalent diameter. The packing density was lower (i.e., the powder bed contained more voids in between particles) for the Ti–6Al–4V particles. The comparison of the tomographic results with laser diffraction, as another particle size measurement technique, proved to be in agreement.
KW - Additive manufacturing
KW - Laser beam melting
KW - Synchrotron computed tomography
KW - Powder analysis
KW - Imaging
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474070
DO - https://doi.org/10.3390/qubs3010003
SN - 2412-382X
VL - 3
IS - 1
SP - 3, 1
EP - 12
PB - MDPI
AN - OPUS4-47407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
A1 - Cabeza, S.
A1 - Mishurova, Tatiana
A1 - Nadammal, Naresh
A1 - Thiede, Tobias
A1 - Bruno, Giovanni
T1 - Residual Stresses in Selective Laser Melted Samples of a Nickel Based Superalloy
N2 - Additive Manufacturing (AM) through the Selective Laser Melting (SLM) route offers ample scope for producing geometrically complex parts compared to the conventional subtractive manufacturing strategies. Nevertheless, the residual stresses which develop during the fabrication can limit application of the SLM components by reducing the load bearing capacity and by inducing unwanted distortion, depending on the boundary conditions specified during manufacturing. The present study aims at characterizing the residual stress states in the SLM parts using different diffraction methods. The material used is the nickel based superalloy Inconel 718. Microstructure as well as the surface and bulk residual stresses were characterized. For the residual stress analysis, X-ray, synchrotron and neutron diffraction methods were used. The measurements were performed at BAM, at the EDDI beamline of -BESSY II synchrotronand the E3 line -BER II neutron reactor- of the Helmholtz-Zentrum für Materialien und Energie (HZB) Berlin. The results reveal significant differences in the residual stress states for the different characterization techniques employed, which indicates the dependence of the residual state on the penetration depth in the sample. For the surface residual stresses, longitudinal and transverse stress components from X-ray and synchrotron agree well and the obtained values were around the yield strength of the material. Furthermore, synchrotron mapping disclosed gradients along the width and length of the sample for the longitudinal and transverse stress components. On the other hand, lower residual stresses were found in the bulk of the material measured using neutron diffraction. The longitudinal component was tensile and decreased towards the boundary of the sample. In contrast, the normal component was nearly constant and compressive in nature. The transversal component was almost negligible. The results indicate that a stress re-distribution takes place during the deposition of the consecutive layers. Further investigations are planned to study the phenomenon in detail.
T2 - European Conference on Residual Stresses - ECRS10
CY - Leuven, Belgium
DA - 11.09.2018
KW - Additive Manufacturing
KW - Selective Laser Melting
KW - Residual Stresses
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-459818
SN - 978-1-94529-189-0
SN - 978-1-94529-188-3
DO - https://doi.org/10.21741/9781945291890-41
SN - 2474-395X
SN - 2474-3941
VL - 6
SP - 259
EP - 264
PB - Materials Research Forum LLC
CY - Millersville, PA 17551, USA
AN - OPUS4-45981
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D.
A1 - Surmeneva, M.
A1 - Koptioug, A.
A1 - Evsevleev, Sergei
A1 - Léonard, Fabien
A1 - Bruno, Giovanni
A1 - Surmenev, R.
T1 - X-ray computed tomography of multiple-layered scaffolds with controlled gradient cell lattice structures fabricated via additive manufacturing
N2 - In this paper we report on the characterization by X-ray computed tomography of calcium phosphate (CaP) and polycaprolactone (PCL) coatings on Ti-6Al-4V alloy scaffolds used as a material for medical implants. The cylindrical scaffold has greater porosity of the inner part than the external part, thus, mimicking trabecular and cortical bone, respectively. The prismatic scaffolds have uniform porosity. Surface of the scaffolds was modified with calcium phosphate (CaP) and polycaprolactone (PCL) by dip-coating to improve biocompatibility and mechanical properties. Computed tomography performed with X-ray and synchrotron radiation revealed the defects of structure and morphology of CaP and PCL coatings showing small platelet-like and spider-web-like structures, respectively.
KW - Additive manufacturing
KW - Lattice structure
KW - Multiple-layered scaffold
KW - Coating
KW - Medical implants
KW - Computed tomography
KW - Polycaprolactone
KW - Calcium phosphate
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471931
UR - http://stacks.iop.org/1742-6596/1145/i=1/a=012044
DO - https://doi.org/10.1088/1742-6596/1145/1/012044
SN - 1742-6596
VL - 1145
SP - 012044, 1
EP - 7
PB - IOP
AN - OPUS4-47193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D
A1 - Koptyug, A.
A1 - Manabaev, K.
A1 - Léonard, Fabien
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
A1 - Cheneler, D.
A1 - Loza, K.
A1 - Epple, M.
A1 - Surmenev, R.
A1 - Surmeneva, M.
T1 - The impact of post manufacturing treatment of functionally graded Ti6Al4V scaffolds on their surface morphology and mechanical strength
N2 - An ultrasonic vibration post-treatment procedure was suggested for additively manufac-tured lattices. The aim of the present research was to investigate mechanical properties andthe differences in mechanical behavior and fracture modes of Ti6Al4V scaffolds treated withtraditional powder recovery system (PRS) and ultrasound vibration (USV). Scanning electronmicroscopy (SEM) was used to investigate the strut surface and the fracture surface mor-phology. X-ray computed tomography (CT) was employed to evaluate the inner structure,strut dimensions, pore size, as well as the surface morphology of additively manufacturedporous scaffolds. Uniaxial compression tests were conducted to obtain elastic modulus,compressive ultimate strength and yield stress. Finite element analysis was performedfor a body-centered cubic (BCC) element-based model and for CT-based reconstructiondata, as well as for a two-zone scaffold model to evaluate stress distribution during elasticdeformation. The scaffold with PRS post treatment displayed ductile behavior, while USVtreated scaffold displayed fragile behavior. Double barrel formation of PRS treated scaffoldwas observed during deformation. Finite element analysis for the CT-based reconstructionrevealed the strong impact of surface morphology on the stress distribution in comparisonwith BCC cell model because of partially molten metal particles on the surface of struts,which usually remain unstressed.
KW - Additive manufacturing
KW - Electron beam melting
KW - Computed tomography
KW - FEM
KW - Lattice structures
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505960
DO - https://doi.org/10.1016/j.jmrt.2019.12.019
SN - 2238-7854
VL - 9
IS - 2
SP - 1866
EP - 1881
PB - Elsevier B.V.
AN - OPUS4-50596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artzt, K.
A1 - Mishurova, Tatiana
A1 - Bauer, P.-P.
A1 - Gussone, J.
A1 - Barriobero-Vila, P.
A1 - Evsevleev, Sergei
A1 - Bruno, Giovanni
A1 - Requena, G.
A1 - Haubrich, J.
T1 - Pandora’s Box–Influence of Contour Parameters on Roughness and Subsurface Residual Stresses in Laser Powder Bed Fusion of Ti-6Al-4V
N2 - The contour scan strategies in laser powder bed fusion (LPBF) of Ti-6Al-4V were studied at the coupon level. These scan strategies determined the surface qualities and subsurface residual stresses. The correlations to these properties were identified for an optimization of the LPBF processing. The surface roughness and the residual stresses in build direction were linked: combining high laser power and high scan velocities with at least two contour lines substantially reduced the surface roughness, expressed by the arithmetic mean height, from values as high as 30 μm to 13 μm, while the residual stresses rose from ~340 to about 800 MPa. At this stress level, manufactured rocket fuel injector components evidenced macroscopic cracking. A scan strategy completing the contour region at 100 W and 1050 mm/s is recommended as a compromise between residual stresses (625 MPa) and surface quality (14.2 μm). The LPBF builds were monitored with an in-line twin-photodiode-based melt pool monitoring (MPM) system, which revealed a correlation between the intensity quotient I2/I1, the surface roughness, and the residual stresses. Thus, this MPM system can provide a predictive estimate of the surface quality of the samples and resulting residual stresses in the material generated during LPBF.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Contour scan strategy
KW - Surface roughness
KW - Melt pool monitoring
KW - Residual stress
KW - Synchrotron X-ray diffraction
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510585
DO - https://doi.org/10.3390/ma13153348
VL - 13
IS - 15
SP - 3348
AN - OPUS4-51058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Sydow, B.
A1 - Thiede, Tobias
A1 - Sizova, I.
A1 - Ulbricht, Alexander
A1 - Bambach, M.
A1 - Bruno, Giovanni
T1 - Residual Stress and Microstructure of a Ti-6Al-4V Wire Arc Additive Manufacturing Hybrid Demonstrator
N2 - Wire Arc Additive Manufacturing (WAAM) features high deposition rates and, thus, allows production of large components that are relevant for aerospace applications. However, a lot of aerospace parts are currently produced by forging or machining alone to ensure fast production and to obtain good mechanical properties; the use of these conventional process routes causes high tooling and material costs. A hybrid approach (a combination of forging and WAAM) allows making production more efficient. In this fashion, further structural or functional features can be built in any direction without using additional tools for every part. By using a combination of forging basic geometries with one tool set and adding the functional features by means of WAAM, the tool costs and material waste can be reduced compared to either completely forged or machined parts. One of the factors influencing the structural integrity of additively manufactured parts are (high) residual stresses, generated during the build process. In this study, the triaxial residual stress profiles in a hybrid WAAM part are reported, as determined by neutron diffraction. The analysis is complemented by microstructural investigations, showing a gradient of microstructure (shape and size of grains) along the part height. The highest residual stresses were found in the transition Zone (between WAAM and forged part). The total stress range showed to be lower than expected for WAAM components. This could be explained by the thermal history of the component.
KW - Additive manufacturing
KW - Neutron diffraction
KW - Residual stress
KW - Hybrid manufacturing
KW - WAAM
KW - Ti-6Al-4V
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508245
DO - https://doi.org/10.3390/met10060701
VL - 10
IS - 6
SP - 701
PB - MDPI
AN - OPUS4-50824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Schneider, J.
A1 - Kupsch, Andreas
A1 - Bruno, Giovanni
T1 - Using SXRR to Probe the Nature of Discontinuities in SLM Additive Manufactured Inconel 718 Specimens
N2 - The utilization of additive manufacturing (AM) to fabricate robust structural components relies on understanding the nature of internal anomalies or discontinuities, which can compromise the structural integrity. While some discontinuities in AM microstructures stem from similar mechanisms as observed in more traditional processes such as casting, others are unique to the AM process. Discontinuities in AM are challenging to detect, due to their submicron size and orientation dependency. Toward the goal of improving structural integrity, minimizing discontinuities in an AM build requires an understanding of the mechanisms of formation to mitigate their occurrence. This study utilizes various techniques to evaluate the shape, size, nature and distribution of discontinuities in AM Inconel 718, in a non-hot isostatic pressed (HIPed) as-built, non-HIPed and direct age, and HIPed with two step age samples. Non-destructive synchrotron radiation refraction and transmission radiography (SXRR) provides additional information beyond that obtained with destructive optical microscopy. SXRR was able to distinguish between voids, cracks and lack of melt in, due to its sensitivity to the orientation of the discontinuity.
KW - Additive manufacturing
KW - X-ray refraction radiography
KW - INCONEL 718
KW - Selective laser melting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509836
DO - https://doi.org/10.1007/s11661-020-05847-5
SN - 1543-1940
VL - 51
IS - 8
SP - 4146
EP - 4157
PB - Springer
AN - OPUS4-50983
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Artzt, K.
A1 - Haubrich, J.
A1 - Evsevleev, Sergei
A1 - Evans, Alexander
A1 - Meixner, M.
A1 - Serrano-Munoz, Itziar
A1 - Sevostianov, I.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Connecting Diffraction-Based Strain with Macroscopic Stresses in Laser Powder Bed Fused Ti-6Al-4V
N2 - The laser powder bed fusion (LPBF) production process often results in large residual stress (RS) in the parts. Nondestructive techniques to determine RS are badly needed. However, a reliable quantification of macro-RS (i.e., stress at the component level) by means of diffraction-based techniques is still a great challenge, because the link between diffraction-based strain and macro-RS is not trivial. In this study, we experimentally determine (by means of in-situ synchrotron radiation diffraction) this link for LPBF Ti-6Al-4V. We compare our results with commonly used models to determine the so-called diffraction elastic constants (DECs). We show that LPBF materials possess different DECs than wrought alloys, simply because their microstructural and mechanical properties are different. We also show that the existing models can be used to calculate DECs only if high accuracy of the RS values is not required. If the peculiarities of the microstructure have to be taken into account (as is the case of additively manufactured materials), a radically new approach is desirable.
KW - Tiatanium
KW - Synchrotron X-ray diffraction
KW - Macroscopic stress
KW - Laser powder bed fusion
KW - Texture
KW - Diffraction elastic constants
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506483
DO - https://doi.org/10.1007/s11661-020-05711-6
VL - 51
IS - 6
SP - 3194
EP - 3204
PB - Springer
AN - OPUS4-50648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evsevleev, Sergei
A1 - Sevostianov, I.
A1 - Mishurova, Tatiana
A1 - Hofmann, M.
A1 - Garcés, G.
A1 - Bruno, Giovanni
T1 - Explaining Deviatoric Residual Stresses in Aluminum Matrix Composites with Complex Microstructure
N2 - The residual stresses in multiphase metal Matrix composites with both random planar-oriented short fibers and particles were studied by neutron diffraction and by a model based on the reformulation of classic Maxwell’s homogenization method. Contrary to common understanding and state-of-the-art models, we experimentally observed that randomly oriented phases possess non-hydrostatic residual stress. The recently developed modeling Approach allows calculating the residual stress in all phases of the composites. It rationalizes the presence of deviatoric stresses Accounting for the interaction of random oriented phases with fibers having preferential orientation.
KW - Metal matrix composite
KW - Residual stress
KW - Deviatoric
KW - Micromechanics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506472
DO - https://doi.org/10.1007/s11661-020-05697-1
VL - 51
IS - 6
SP - 3104
EP - 3113
PB - Springer
AN - OPUS4-50647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mieller, Björn
T1 - Influence of test procedure on dielectric breakdown strength of alumina
N2 - Dielectric strength testing of ceramics can be performed with various setups and parameters. Comparisons of results from different sources are often not meaningful, because the results are strongly dependent on the actual testing procedure. The aim of this study is to quantify the influence of voltage ramp rate, electrode size, electrode conditioning, and sample thickness on the measured AC dielectric strength of a commercial alumina. Mean values, Weibull moduli, and failure probabilities determined in standardized short time tests are evaluated and related to withstand voltage tests. Dielectric strength values in the range from 21.6 to 33.2 kV/mm were obtained for the same material using different testing procedures. Short time tests resulted in small standard deviations (< 2 kV/mm) and high Weibull moduli around 30, while withstand tests at voltage levels with low and virtual zero failure probability in short time tests resulted in large scatter of withstand time and Weibull moduli < 1. The strong decrease in Weibull moduli is attributed to progressive damage from partial discharge and depolarization during AC testing. These findings emphasize the necessity of a thorough documentation of testing procedure and highlight the importance of withstand voltage tests for a comprehensive material characterization.
KW - Ceramic
KW - High-voltage testing
KW - Dielectric breakdown
KW - Alumina
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483852
DO - https://doi.org/10.1007/s40145-018-0310-4
SN - 2226-4108
SN - 2227-8508
VL - 8
IS - 2
SP - 247
EP - 255
PB - Springer
AN - OPUS4-48385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Mishurova, Tatiana
A1 - Thiede, Tobias
A1 - Sprengel, Maximilian
A1 - Kromm, Arne
A1 - Nadammal, Naresh
A1 - Nolze, Gert
A1 - Saliwan Neumann, Romeo
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - The residual stress in as‑built Laser Powder Bed Fusion IN718 alloy as a consequence of the scanning strategy induced microstructure
N2 - The effect of two types of scanning strategies on the grain structure and build-up of Residual Stress (RS) has been investigated in an as-built IN718 alloy produced by Laser Powder Bed Fusion (LPBF). The RS state has been investigated by X-ray diffraction techniques. The microstructural characterization was performed principally by Electron Backscatter Diffraction (EBSD), where the application of a post-measurement refinement technique enables small misorientations (< 2°) to be resolved. Kernel average misorientation (KAM) distributions indicate that preferably oriented columnar grains contain higher levels of misorientation, when compared to elongated grains with lower texture. The KAM distributions combined with X-ray diffraction stress maps infer that the increased misorientation is induced via plastic deformation driven by the thermal stresses, acting to self-relieve stress. The possibility of obtaining lower RS states in the build direction as a consequence of the influence of the microstructure should be considered when envisaging scanning strategies aimed at the mitigation of RS.
KW - Additive manufacturing
KW - LPBF
KW - Residual stress
KW - Inconel 718
KW - Kernel average misorientation
KW - Texture
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511769
DO - https://doi.org/10.1038/s41598-020-71112-9
VL - 10
IS - 1
SP - 14645
AN - OPUS4-51176
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ziesche, R.
A1 - Robinson, J.
A1 - Kok, M.
A1 - Markötter, Henning
A1 - Kockelmann, W.
A1 - Kardjilov, N.
A1 - Manke, I.
A1 - Brett, D.
A1 - Shearing, P.
T1 - Editors’ Choice—4D Neutron and X-ray Tomography Studies of High Energy Density Primary Batteries: Part I. Dynamic Studies of LiSOCl2 during Discharge
N2 - The understanding of dynamic processes in Li-metal batteries is an important consideration to enable the full capacity of cells to be utilised. These processes, however, are generally not directly observable using X-ray techniques due to the low attenuation of Li; and are challenging to visualise using neutron imaging due to the low temporal resolution of the technique. In this work, complementary X-ray and neutron imaging are combined to track the dynamics of Li within a primary Li/SOCl2 cell. The temporal challenges posed by neutron imaging are overcome using the golden ratio imaging method which enables the identification of Li diffusion in operando. This combination of techniques has enabled an improved understanding of the processes which limit rate performance in Li/SOCl2 cells and may be applied beyond this chemistry to other Li-metal cells.
KW - Nneutron imaging
KW - X-ray imaging
KW - Tomography
KW - Primary Battery
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515802
DO - https://doi.org/10.1149/1945-7111/abbbbc
SN - 1945-7111
VL - 13
IS - 167
SP - 130545
PB - IOP Publishing
AN - OPUS4-51580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Magkos, Sotirios
A1 - Kupsch, Andreas
A1 - Bruno, Giovanni
T1 - Direct iterative reconstruction of computed tomography trajectories: Reconstruction from limited number of projections with DIRECTT
N2 - X-ray computed tomography has many applications in materials science and non-destructive testing. While the standard filtered back-projection reconstruction of the radiographic data sets is fast and simple, it typically fails in returning accurate results from missing or inconsistent projections. Among the alternative techniques that have been proposed to handle such data is the Direct Iterative REconstruction of Computed Tomography Trajectories (DIRECTT) algorithm. We describe a new approach to the algorithm, which significantly decreases the computational time, while achieving a better reconstruction quality than that of other established algorithms.
KW - Computed tomography
KW - DIRECTT
KW - Iterative reconstruction
KW - Limited data
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514403
DO - https://doi.org/10.1063/5.0013111
SN - 0034-6748
VL - 91
IS - 10
SP - 103107-1
EP - 103107-8
PB - AIP Publishing
CY - Melville, NY, USA
AN - OPUS4-51440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Johann, Sergej
A1 - Bartholmai, Matthias
T1 - Smart RFID Sensors Embedded in Building Structures for Early Damage Detection and Long-Term Monitoring
N2 - In civil engineering, many structures are made of reinforced concrete. Most Degradation processes relevant to this material, e.g., corrosion, are related to an increased level of material moisture.
Therefore, moisture monitoring in reinforced concrete is regarded as a crucial method for structural health monitoring. In this study, passive radio frequency identification (RFID)-based sensors are embedded into the concrete. They are well suited for long-term operation over decades and are well protected against harsh environmental conditions. The energy supply and the data transfer of the humidity sensors are provided by RFID. The sensor casing materials are optimised to withstand the high alkaline environment in concrete, having pH values of more than 12. Membrane materials are also investigated to identify materials capable of enabling water vapour transport from the porous cement matrix to the embedded humidity sensor. By measuring the corresponding relative humidity with embedded passive RFID-based sensors, the cement hydration is monitored for 170 days.
Moreover, long-term moisture monitoring is performed for more than 1000 days. The Experiments show that embedded passive RFID-based sensors are highly suitable for long-term structural health monitoring in civil engineering.
KW - RFID based sensors
KW - Embedded sensors
KW - Corresponding relative humidity
KW - Porous building materials
KW - Reinforced concrete
KW - Corrosion
KW - Civil engineering
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500831
DO - https://doi.org/10.3390/s19245514
VL - 19
IS - 24
SP - 1
EP - 18
PB - MDPI
CY - Basel, Swiss
AN - OPUS4-50083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sebald, M.A.
A1 - Gebauer, J.
A1 - Sommerfeld, Thomas
A1 - Koch, Matthias
T1 - First Synthesis of (−)-Altenuene-D3 Suitable as Internal Standard for Isotope Dilution Mass Spectrometry
N2 - Metabolites from Alternaria fungi exhibit a variety of biological properties such as phytotoxic, cytotoxic, or antimicrobial activity. Optimization of a literature procedure culminated in an efficient total synthesis of (−)-altenuene as well as a stable isotope-labeled derivative suitable for implementation in a LC-MS/MS method for mycotoxin analysis.
KW - Altenuene
KW - Alternaria mycotoxins
KW - Food safety
KW - Isotope-labeled
KW - SIDA-LC-MS/MS
KW - Suzuki coupling
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-500696
DO - https://doi.org/10.3390/molecules24244563
SN - 1420-3049
VL - 24
SP - 4563
PB - MDPI
CY - Basel
AN - OPUS4-50069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kneipp, Janina
A1 - Zancajo, Victor M.R.
A1 - Diehn, S.
A1 - Filiba, N.
A1 - Elbaum, R.
T1 - Spectroscopic Discrimination of Sorghum Silica Phytoliths
N2 - Grasses accumulate silicon in the form of silicic acid, which is precipitated as amorphous silica in microscopic particles termed phytoliths. These particles comprise a variety of morphologies according to the cell type in which the silica was deposited. Despite the evident morphological differences, phytolith chemistry has mostly been analysed in bulk samples, neglecting differences between the varied types formed in the same species. In this work, we extracted leaf phytoliths from mature plants of Sorghum bicolor (L.) Moench. Using solid state NMR and thermogravimetric analysis, we show that the extraction methods alter greatly the silica molecular structure, its condensation degree and the trapped organic matter. Measurements of individual phytoliths by Raman and synchrotron FTIR microspectroscopies in combination with multivariate analysis separated bilobate silica cells from prickles and long cells, based on the silica molecular structures and the fraction and composition of occluded organic matter. The variations in structure and composition of sorghum phytoliths suggest that the biological pathways leading to silica deposition vary between these cell types.
KW - Phytoliths
KW - Biosilicification
KW - Raman
KW - Sorghum
KW - Solid state NMR
KW - Synchrotron FTIR
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502672
DO - https://doi.org/10.3389/fpls.2019.01571
VL - 10
SP - 1571
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-50267
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, C.
A1 - Hensen, C.
A1 - Wallmann, K.
A1 - Liebetrau, V.
A1 - Tatzel, Michael
A1 - Schurr, S. L.
A1 - Kutterolf, S.
A1 - Haffert, L.
A1 - Geilert, Sonja
A1 - Hübscher, C.
A1 - Lebas, E.
A1 - Heuser, A.
A1 - Schmidt, M.
A1 - Strauss, H.
A1 - Vogl, Jochen
A1 - Hansteen, T.
T1 - Origin of High Mg and SO4 Fluids in Sediments of the Terceira Rift, Azores‐Indications for Caminite Dissolution in a Waning Hydrothermal System
N2 - During R/V Meteor cruise 141/1, pore fluids of near surface sediments were investigated to find indications for hydrothermal activity in the Terceira Rift (TR), a hyperslow spreading center in the Central North Atlantic Ocean. To date, submarine hydrothermal fluid venting in the TR has only been reported for the D. João de Castro seamount, which presently seems to be inactive. Pore fluids sampled close to a volcanic cone at 2,800‐m water depth show an anomalous composition with Mg, SO4, and total alkalinity concentrations significantly higher than seawater and a nearby reference core. The most straightforward way of interpreting these deviations is the dissolution of the hydrothermally formed mineral caminite (MgSO4 0.25 Mg (OH)2 0.2H2O). This interpretation is corroborated by a thorough investigation of fluid isotope systems (δ26Mg, δ30Si, δ34S, δ44/42Ca, and 87Sr/86Sr). Caminite is known from mineral assemblages with anhydrite and forms in hydrothermal recharge zones only under specific conditions such as high fluid temperatures and in altered oceanic crust, which are conditions generally met at the TR. We hypothesize that caminite was formed during hydrothermal activity and is now dissolving during the waning state of the hydrothermal system, so that caminite mineralization is shifted out of its stability zone. Ongoing fluid circulation through the basement is transporting the geochemical signal via slow advection toward the seafloor.
KW - Isotope ratio
KW - Delta value
KW - Pore fluids
KW - Magnesium
KW - Hydrothermal fluid
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503430
DO - https://doi.org/10.1029/2019GC008525
VL - 20
IS - 12
SP - 6078
EP - 6094
PB - Wiley
AN - OPUS4-50343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Mirtsch, Mona
ED - Mangelsdorf, Axel
ED - Weiler, Petra
T1 - Konformitätsbewertung im Bereich Cybersicherheit
N2 - Das Ziel dieses Kapitels besteht darin, die Rolle von Konformitätsbewertung für die Erhöhung der Cybersicherheit von Produkten, Dienstleistungen und Prozessen zu betrachten. Dazu wird der Begriff Cybersicherheit beleuchtet sowie ausgewählte Cybersicherheitsnormen kurz vorgestellt. Im Folgenden wird der regulative europäische Rahmen für die Konformitätsbewertung aus ordnungspolitischer Sicht sowie der aktuelle Verordnungsentwurf zum Cybersecurity Act dargestellt und kritsch beleuchtet.
KW - Cybersicherheit
KW - Konformitätsbewertung
KW - Cybersecurity Act
KW - Normen
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473829
UR - https://www.degruyter.com/downloadpdf/books/9783110629057/9783110629057-009/9783110629057-009.pdf
SN - 978-3-11062-905-7
DO - https://doi.org/10.1515/9783110629057
SP - 141
EP - 164
PB - De Gruyter
CY - Berlin, Boston
ET - 1
AN - OPUS4-47382
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Domonov, D.P.
A1 - Pechenyuk, S.I.
A1 - Semushina, Y.P.
A1 - Yusenko, Kirill
T1 - Solid state transformation in inner coordination sphere of [Co(NH3)6][Fe(C2O4)3]·3H2O as a route to access catalytically active Co-Fe materials
N2 - Thermal decomposition of [Co(NH₃)₆][Fe(C₂O₄)₃]∙3H₂O in argon atmosphere, at a low heating rate (3°/min), and in large amounts of the initial complex (~0.1 mole), has been studied. It was possible to distinguish four decomposition steps upon heating: In the temperature range of 50⁻100 °C-the loss of crystal water; 100⁻190 °C-stability region of dehydrated complex; 230⁻270 °C-the range of stability of intermediate phase with the formula CoFe(NH₃)₂(C₂O₄)₂; 270⁻350 °C-thermal decomposition of the intermediate with the formation of metallic products and further air oxidation with the formation of Co1.5Fe1.5O₄. Catalytic properties of thermolysis products were tested in the decomposition reaction of H₂O₂ (inactive), oxidation of acetone (average activity), and decomposition of ammonium perchlorate (highly active).
KW - Double complex salts
KW - Catalysts
KW - Single-source precursors
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474014
DO - https://doi.org/10.3390/ma12020221
SN - 1996-1944
VL - 12
IS - 2
SP - 221, 1
EP - 10
PB - mdpi
CY - Zürich
AN - OPUS4-47401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholtz, G.
A1 - Staude, Andreas
A1 - Dunlop, J.A.
T1 - Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities
N2 - Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with the cuticular lenses and little was known about internal anatomy. Only recently some data on crystalline cones and retinula cells were reported for a Cambrian trilobite species. Here, we describe internal eye structures of two other trilobite genera. The Ordovician Asaphus sp. reveals preserved crystalline cones situated underneath the cuticular lenses. The same is true for the Devonian species Archegonus (Waribole) warsteinensis, which in addition shows the fine structure of the rhabdom in the retinula cells. These results suggest that an apposition eye with a crystalline cone is ancestral for Trilobita. The overall similarity of trilobite eyes to those of myriapods, crustaceans, and hexapods corroborates views of a phylogenetic position of trilobites in the stem lineage of Mandibulata.
KW - Trilobite compound eyes
KW - Computed Tomography
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510784
DO - https://doi.org/10.1038/s41467-019-10459-8
SN - 2041-1723
VL - 10
SP - 2503
PB - Nature
AN - OPUS4-51078
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Choi, Youngeun
A1 - Schmidt, Carsten
A1 - Tinnefeld, Philip
A1 - Bald, Ilko
A1 - Roedinger, Stefan
T1 - A new reporter design based on DNA origami nanostructures for quantification of short oligonucleotides using microbeads
N2 - The DNA origami technique has great potential for the development of brighter and more sensitive reporters for fluorescence based detection schemes such as a microbead-based assay in diagnostic applications. The nanostructures can be programmed to include multiple dye molecules to enhance the measured signal as well as multiple probe strands to increase the binding strength of the target oligonucleotide to these nanostructures. Here we present a proof-of-concept study to quantify short oligonucleotides by developing a novel DNA origami based reporter system, combined with planar microbead assays. Analysis of the assays using the VideoScan digital imaging platform showed DNA origami to be a more suitable reporter candidate for quantification of the target oligonucleotides at lower concentrations than a conventional reporter that consists of one dye molecule attached to a single stranded DNA. Efforts have been made to conduct multiplexed analysis of different targets as well as to enhance fluorescence signals obtained from the reporters. We therefore believe that the quantification of short oligonucleotides that exist in low copy numbers is achieved in a better way with the DNA origami nanostructures as reporters.
KW - Origami
KW - Nanostructures
KW - Microbeads
KW - DNA origami
KW - Oligonucleotides
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476443
DO - https://doi.org/10.1038/s41598-019-41136-x
SN - 2045-2322
VL - 9
SP - 4769, 1
EP - 8
PB - Nature
AN - OPUS4-47644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Treiling, S.
A1 - Wang, Cui
A1 - Förster, C.
A1 - Reichenauer, F.
A1 - Kalmbach, J.
A1 - Boden, P.
A1 - Harris, J. P.
A1 - Carrella, L. M.
A1 - Rentschler, E.
A1 - Resch-Genger, Ute
A1 - Reber, C.
A1 - Seitz, M.
A1 - Gerhards, M.
A1 - Heinze, K.
T1 - Luminescence and Light-Driven Energy and Electron Transfer from an Exceptionally Long-Lived Excited State of a Non-Innocent Chromium(III) Complex
N2 - Photoactive metal complexes employing Earth‐abundant metal ions are a key to sustainable photophysical and photochemical applications. We exploit the effects of an inversion center and ligand non‐innocence to tune the luminescence and photochemistry of the excited state of the [CrN6] chromophore [Cr(tpe)2]3+ with close to octahedral symmetry (tpe=1,1,1‐tris(pyrid‐2‐yl)ethane). [Cr(tpe)2]3+ exhibits the longest luminescence lifetime (τ=4500 μs) reported up to date for a molecular polypyridyl chromium(III) complex together with a very high luminescence quantum yield of Φ=8.2 % at room temperature in fluid solution. Furthermore, the tpe ligands in [Cr(tpe)2]3+ are redox non‐innocent, leading to reversible reductive chemistry. The excited state redox potential and lifetime of [Cr(tpe)2]3+ surpass those of the classical photosensitizer [Ru(bpy)3]2+ (bpy=2,2′‐bipyridine) enabling energy transfer (to oxygen) and photoredox processes (with azulene and tri(n‐butyl)amine).
KW - Quantum yield
KW - Cr(III) complex
KW - Longst luminescence lifetime
KW - Electron transfer
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494870
DO - https://doi.org/10.1002/anie.201909325
VL - 58
SP - 2
EP - 13
PB - Wiley-VCH
AN - OPUS4-49487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strangfeld, Christoph
A1 - Stolpe, Heiko
A1 - Kruschwitz, Sabine
ED - Schumann, R.
T1 - Correlation between the electric impedance and the water layer thickness in partially saturated screed samples
N2 - The moisture content of screed samples is monitored by means of embedded sensors. Relative humidity sensors and multi-ring-electrodes are used to measure the spatial moisture distribution during desorption. Based on the humidity data and the pore volume distribution, the moisture and the water layer thickness within the pore space are predicted.
Slit shape as well as cylindrical pores are evaluated. Finally, the measured real part of the electrical impedance and the calculated water layer thickness are correlated. Based on the available data, a significant trend change of the impedance is documented at a water layer thickness of approximately 3 nm. This water layer thickness corresponds to a relative humidity of 88.3%.
T2 - 10. CMM Tagung
CY - Ettlingen, Germany
DA - 10.10.2019
KW - Material moisture
KW - Screed
KW - Embedded sensors
KW - Electric impedance
KW - Water layer thickness
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494636
VL - 10
SP - 79
EP - 102
PB - CMM, Karlsruher Institut für Technologie
CY - Karlsruhe
AN - OPUS4-49463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Silke
A1 - Roethke, A.
A1 - Rienitz, O.
A1 - Matschat, Ralf
A1 - Schiel, D.
A1 - Jaehrling, R.
A1 - Goerlitz, V.
A1 - Kipphardt, Heinrich
T1 - SI-traceable monoelemental solutions on the highest level of accuracy: 25 years from the foundation of CCQM to recent advances in the development of measurement methods
N2 - Within the Working Group on Inorganic Analysis (IAWG) of the Consultative Committee for Amount of Substance: Metrology in Chemistry and Biology (CCQM) international key comparisons and pilot studies related to inorganic analysis are carried to ensure consistency in this field at the highest level. Some of these comparisons deal directly with the preparation and characterization of monoelemental solutions or with topics, closely related. The importance of monoelemental solutions lies in the fact that almost every measurement in inorganic analysis relies on the comparison with either a reference material, or references in form of solutions, usually (mono)elemental solutions. All quantitative measurement approaches, e.g. isotope dilution or standard addition, need an accurate reference solution made from a well characterized reference material, prepared under full gravimetric control. These primary (monoelemental) solutions do not only serve as arbitrary references/calibration solutions, but they also link up measurement results to the International System of units (SI), this way establishing the so-called metrological traceability to a measurement unit of the SI. Without such solutions on the highest possible level of accuracy and with the smallest possible associated uncertainties (for e.g. element content and/or impurities), an analysis itself can never be as good as it could be with appropriate reference solutions. This article highlights select key comparisons and pilot studies dealing with monoelemental solution related topics within the IAWG from the foundation of CCQM – 25 years ago – up to latest achievements in the field of inorganic analysis.
KW - Metrology
KW - SI Traceability
KW - CCQM
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496080
DO - https://doi.org/10.1088/1681-7575/ab5636
SN - 0026-1394
SN - 1681-7575
SP - 1
EP - 23
PB - IOP
CY - Bristol
AN - OPUS4-49608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Pfüger, Mika
A1 - Velasco-Vélez, Juan-Jesús
A1 - Sahre, Mario
A1 - Radnik, Jörg
A1 - Bernicke, Michael
A1 - Bernsmeier, Denis
A1 - Hodoroaba, Vasile-Dan
A1 - Krumrey, Michael
A1 - Strasser, Peter
A1 - Kraehnert, Ralph
A1 - Hertwig, Andreas
T1 - Assessing optical and electrical properties of highly active IrOx catalysts for the electrochemical oxygen evolution reaction via spectroscopic ellipsometry
N2 - Efficient water electrolysis requires highly active electrodes. The activity of corresponding catalytic coatings strongly depends on material properties such as film thickness, crystallinity, electrical conductivity, and chemical surface speciation. Measuring these properties with high accuracy in vacuum-free and nondestructive methods facilitates the elucidation of structure−activity relationships in realistic environments. Here, we report a novel approach to analyze the optical and electrical properties of highly active oxygen evolution reaction (OER) catalysts via spectroscopic ellipsometry (SE). Using a series of differently calcined, mesoporous, templated iridium oxide films as an example, we assess the film thickness, porosity, electrical resistivity, electron concentration, electron mobility, and interband and intraband transition energies by modeling of the optical spectra. Independently performed analyses using scanning electron microscopy, energy-dispersive X-ray spectroscopy, ellipsometric porosimetry, X-ray reflectometry, and absorption spectroscopy indicate a high accuracy of the deduced material properties. A comparison of the derived analytical data from SE, resonant photoemission spectroscopy, X-ray absorption spectroscopy, and X-ray photoelectron spectroscopy with activity measurements of the OER suggests that the intrinsic activity of iridium oxides scales with a shift of the Ir 5d t2g sub-level and an increase of p−d interband transition energies caused by a transition of μ1-OH to μ3-O species.
KW - Spectroscopic ellipsometry
KW - Electrocatalysis
KW - Oxygen evolution reaction
KW - Mesoporous iridium oxide films
KW - Non-destructive ambient analysis
KW - Intrinsic OER activity
KW - Complementary methodology and metrology
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516288
DO - https://doi.org/10.1021/acscatal.0c03800
SN - 2155-5435
VL - 10
IS - 23
SP - 14210
EP - 14223
PB - American Chemical Society
AN - OPUS4-51628
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Agroui, K.
A1 - Jaunich, Matthias
A1 - Hadj Arab, A.
T1 - Analysis techniques of polymeric encapsulant materials for photovoltaic modules: situation and perspectives
N2 - The properties of the encapsulant are critical to the long-term performance of photovoltaic (PV) modules under the influence of sunlight including UV, elevated temperature, humidity and diffusion of oxygen. Encapsulation process represents a bout 40% of the whole PV module cost. The introduction of new non-EVA encapsulant material type "Low-Cost, High-Performance" should provide a solution to outdoor yellowing degradation problems. The emerging encapsulant materials exhibit a good compatibility with emerging PV solar cells for long term durability. This new generation of encapsulant materials has the advantage to improve e the PV module performances and long term durability for specific climate like desert regions. This scientific contribution presents an overview of the different encapsulant materials currently on the market, the general requirements of the emerging encapsulant materials and characterizations techniques for degradation, diagnostic and reliability lifetime estimation in the framework of Algerian renewable energy strategy.
T2 - Africa-EU Renewable Energy Re search and Innovation Symposium, RERIS 2016
CY - Tlemcen, Algeria
DA - 08.03.2016
KW - Solar cell
KW - Polymer encapsulant
KW - PV module
KW - Encapsulation process
KW - Analysis technique
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377186
DO - https://doi.org/10.1016/j.egypro.2016.07.171
SN - 1876-6102
VL - 2016
IS - 93
SP - 203
EP - 210
PB - Elsevier Ltd.
AN - OPUS4-37718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babick, F.
A1 - Mielke, Johannes
A1 - Wohlleben, W.
A1 - Weigel, St.
A1 - Hodoroaba, Vasile-Dan
T1 - How reliably can a material be classified as a nanomaterial? Available particle-sizing techniques at work
N2 - Currently established and projected regulatory frameworks require the classification of materials (whether nano or non-nano) as specified by respective definitions, most of which are based on the size of the constituent particles. This brings up the question if currently available techniques for particle size determination are capable of reliably classifying materials that potentially fall under these definitions.
In this study, a wide variety of characterisation techniques, including counting, fractionating, and spectroscopic techniques, has been applied to the same set of materials under harmonised conditions.
The selected materials comprised well-defined Quality control materials (spherical, monodisperse) as well as industrial materials of complex shapes and considerable polydispersity. As a result, each technique could be evaluated with respect to the determination of the number-weighted median size. Recommendations on the most appropriate and efficient use of techniques for different types of material are given.
KW - Nanomaterial classification
KW - Nanoparticle
KW - Number-weighted median size
KW - Tiered
KW - Particle size analysis
KW - Nanometrology
KW - Characterisation techniques
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367922
UR - http://link.springer.com/article/10.1007/s11051-016-3461-7
DO - https://doi.org/10.1007/s11051-016-3461-7
SN - 1388-0764
SN - 1572-896X
VL - 18
IS - 6
SP - Article 158, 1
EP - 40
PB - Springer
AN - OPUS4-36792
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, Heike
A1 - Knigge, Xenia
A1 - Knapic, D.
A1 - Weise, Matthias
A1 - Sahre, Mario
A1 - Hertwig, Andreas
A1 - Sacco, A.
A1 - Rossi, A. M.
A1 - Radnik, Jörg
A1 - Müller, Kai
A1 - Wasmuth, Karsten
A1 - Krüger, Jörg
A1 - Hassel, A. W.
A1 - Hodoroaba, Vasile-Dan
A1 - Bonse, Jörn
T1 - Picosecond laser processing of hierarchical micro–nanostructures on titanium alloy upon pre- and postanodization: morphological, structural, and chemical effects
N2 - Recent publications indicate that the order of electrochemical anodization (before or after the laser processing step) plays an important role for the response of bone-forming osteoblasts—an effect that can be utilized for improving permanent dental or removable bone implants. For exploring these different surface functionalities, multimethod morphological, structural, and chemical characterizations are performed in combination with electrochemical pre- and postanodization for two different characteristic microspikes covered by nanometric laser-induced periodic surface structures on Ti–6Al–4V upon irradiation with near-infrared ps-laser pulses (1030 nm wavelength, ≈1 ps pulse duration, 67 and 80 kHz pulse repetition frequency) at two distinct sets of laser fluence and beam scanning parameters. This work involves morphological and topographical investigations by scanning electron microscopy and white light interference microscopy, structural material examinations via X-ray diffraction, and micro-Raman spectroscopy, as well as near-surface chemical analyses by X-ray photoelectron spectroscopy and hard X-ray photoelectron spectroscopy. The results allow to qualify the mean laser ablation depth, assess the spike geometry and surface roughness parameters, and provide new detailed insights into the near-surface oxidation that may affect the different cell growth behavior for pre- or postanodized medical implants.
T2 - 2023 E-MRS Spring Meeting, Symposium L "Making light matter: lasers in material sciences and photonics"
CY - Strasbourg, France
DA - 29.05.2023
KW - Hierarchical micro-nanostructures
KW - Laser-induced periodic surface structures (LIPSS)
KW - Ultrashort laser pulses
KW - Ti-6Al-4V alloy
KW - X-ray photoelectron spectroscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601962
DO - https://doi.org/10.1002/pssa.202300920
SN - 1862-6319
SP - 1
EP - 11
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-60196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlke, Dirk
A1 - Dobrovolskij, P.
A1 - Vrana, J.
A1 - Heckel, Thomas
T1 - Herausforderungen bei der Prüfung von Schmiedeteilen durch Vorsatzkeile für Longitudinalwellenprüfköpfe
N2 - Trotz moderner Sensortechnologien und Rekonstruktionsmethoden, findet die manuelle und automatisierte Ultraschallprüfung durch konventionelle Senkrecht- und Winkelprüfköpfe vielfach industriellen Einsatz.
Um einen flexiblen Prüfeinsatz und die Prüfbarkeit von einfachen sowie komplexen Geometrien zu gewährleisten, werden dort oftmals Vorlaufkeile für die Winkelprüfung mit Longitudinalwellen angewendet um eine Anzeigenschräglage und deren Reflektivität auszugleichen bzw. zu verbessern. Durch den unterschiedlichen Aufbau, im Vergleich zu integrierten Scherwellen-Winkelprüfköpfen, können jedoch während der Prüfung Fehlanzeigen generiert werden. Diese fehlerhaften Anzeigen beruhen auf Mehrfachreflexionen und Wellenumwandlungen innerhalb des Vorlaufkeils, aufgrund der Geometrie und können im Feld nur bedingt von realen Anzeigen unterschieden werden. Dieser Beitrag zeigt die geometrische Betrachtung bei der Verwendung von Vorlaufkeilen und wurde experimentell durch die Bestimmung der Richtcharakteristik und dem Einsatz von elektrodynamischen Sonden validiert. Des Weiteren ermöglichen die so gewonnenen Abhängigkeiten einen vom Keilwinkel abhängigen Verstärkungsausgleich und somit eine korrekte Größenbestimmung durch einen geeigneten Vergleichsfehler.
T2 - DACH-Jahrestagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Richtcharakteristik
KW - Vorlaufkeile
KW - Mehrfachreflexion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480999
VL - 2019
SP - 1
EP - 7
PB - DGZfP Deutsche Gesellschaft für Zerstörungsfreie Prüfung
AN - OPUS4-48099
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, F.
A1 - Sordello, F.
A1 - Mino, L.
A1 - Prozzi, M.
A1 - Mansfeld, Ulrich
A1 - Hodoroaba, Vasile-Dan
A1 - Minero, C.
T1 - Polyethylene Glycol as Shape and Size Controller for the Hydrothermal Synthesis of SrTiO3 Cubes and Polyhedra
N2 - Understanding the correlation between the morphological and functional properties of particulate materials is crucial across all fields of physical and natural sciences. This manuscript reports on the investigation of the effect of polyethylene glycol (PEG) employed as a capping Agent in the synthesis of SrTiO3 crystals. The crucial influence of PEG on both the shape and size of the strontium titanate particles is revealed, highlighting the effect on the photocurrents measured under
UV–Vis irradiation.
KW - Polyethylene glycol
KW - Strontium titanate
KW - Controlled morphology
KW - Photoelectrochemistry
KW - Electron microscopy
KW - EDS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512892
DO - https://doi.org/10.3390/nano10091892
VL - 10
IS - 9
SP - 1892
PB - MDPI
CY - Basel, CH
AN - OPUS4-51289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Habibimarkani, Heydar
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - John, Elisabeth
T1 - Probing Surface Changes in Fe–Ni Oxide Nanocatalysts with a ToF-SIMS-Coupled Electrochemistry Setup and Principal Component Analysis
N2 - Understanding catalyst surface dynamics under operating conditions is essential for improving electrocatalytic performance. Here, we present a novel approach combining electrochemical treatment with contamination-free transfer to Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS), followed by principal component analysis (PCA), to probe surface and interfacial changes in Ni–Fe oxide nanoparticles stabilized by polyvinylpyrrolidone (PVP) during the oxygen evolution reaction (OER). The surface analysis at three distinct treatment stages revealed distinct chemical fingerprints across pristine nanoparticles, after exposure to 1 M KOH electrolyte, and after cyclic voltammetry treatment. The results highlight a progressive transition from ligand-rich to ligand-depleted interfaces, with PVP-related fragments dominant in the early stages and metal- and electrolyte-derived species emerging after activation. Complementary ToF-SIMS analysis of electrolyte deposited on Si wafers after each treatment step confirms the concurrent leaching of PVP and Fe–Ni-based fragments during OER. These findings underscore the dynamic nature of catalyst–electrolyte interfaces and demonstrate a robust strategy for monitoring surface-sensitive chemical changes associated with the nanoparticles, especially during the initial cycles of the OER.
KW - Fe-Ni oxide
KW - Nanocatalysts
KW - ToF-SIMS
KW - Electrochemistry
KW - PCA (principal component analysis)
KW - OER
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652667
DO - https://doi.org/10.1021/acs.analchem.5c03894
SN - 0003-2700
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-65266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Harald
A1 - Hodoroaba, Vasile-Dan
A1 - Schmidt, Alexandra
A1 - Rasmussen, K.
A1 - Rauscher, H.
T1 - Counting Small Particles in Electron Microscopy Images — Proposal for Rules and Their Application in Practice
N2 - Electron microscopy (EM) is the gold standard for the characterisation of the morphology (size and shape) of nanoparticles. Visual observation of objects under examination is always a necessary first step in the characterisation process. Several questions arise when undertaking to identify and count particles to measure their size and shape distribution. In addition to challenges with the dispersion and identification of the particles, more than one protocol for counting particles is in use. This paper focuses on precise rules for the counting of particles in EM micrographs, as this influences the measurement accuracy of the number of particles, thus implicitly affecting the size values of the counted particles. We review and compare four different, commonly used methods for counting, which we then apply in case studies. The impact of the selected counting rule on the obtained final particle size distribution is highlighted. One main aim of this analysis is to support the application of a specific, well-defined counting approach in accordance with regulatory
requirements to contribute to achieving more reliable and reproducible results. It is also useful for the new harmonised measurement procedures for determining the particle size and particle size distribution of nanomaterials.
KW - Nano
KW - Particle size distribution
KW - Nanoparticle
KW - Nanomaterial
KW - OECD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551891
DO - https://doi.org/10.3390/nano12132238
SN - 2079-4991
VL - 12
IS - 13
SP - 2238
PB - MDPI
CY - Basel
AN - OPUS4-55189
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gaillard, C.
A1 - Mech, A.
A1 - Wohlleben, W.
A1 - Babick, F.
A1 - Hodoroaba, Vasile-Dan
A1 - Ghanem, A.
A1 - Weigel, S.
A1 - Rauscher, H.
T1 - A technique-driven materials categorisation scheme to support regulatory identification of nanomaterials
N2 - Worldwide there is a variety of regulatory provisions addressing nanomaterials. The identification as nanomaterial in a regulatory context often has the consequence that specific legal rules apply. In identifying nanomaterials, and to find out whether nanomaterial-specific provisions apply, the external size of particles is globally used as a criterion. For legal certainty, its assessment for regulatory purposes should be based on measurements and methods that are robust, fit for the purpose and ready to be accepted by different stakeholders and authorities. This should help to assure the safety of nanomaterials and at the same time facilitate their international trading. Therefore, we propose a categorisation scheme which is driven by the capabilities of common characterisation techniques for particle size measurement. Categorising materials according to this scheme takes into account the particle properties that are most important for a determination of their size. The categorisation is exemplified for the specific particle number based size metric of the European Commission's recommendation on the definition of nanomaterial, but it is applicable to other metrics as well. Matching the performance profiles of the measurement techniques with the material property profiles (i) allows selecting the most appropriate size determination technique for every type of material considered, (ii) enables proper identification of nanomaterials, and (iii) has the potential to be accepted by regulators, industry and consumers alike. Having such a scheme in place would facilitate the regulatory assessment of nanomaterials in regional legislation as well as in international relations between different regulatory regions assuring the safe trade of nanomaterials.
KW - Nanomaterial
KW - Nanoparticles
KW - Categorisation scheme
KW - EC definition of a nanomaterial
KW - Regulatory identification of nanomaterials
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471623
DO - https://doi.org/10.1039/C8NA00175H
SN - 2516-0230
SP - 1
EP - 11
PB - The Royal Society of Chemistry
AN - OPUS4-47162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Terborg, R.
A1 - Boehm, S.
A1 - Kim, K. J.
T1 - Analysis of elemental composition of Fe1-xNix and Si1-xGex alloy thin films by electron probe microanalysis and micro-focus X-ray fluorescence
N2 - The present study reports on results of analysis of the elemental composition of thin films by electron probe microanalysis with energy dispersive (ED-EPMA) X-ray spectrometry in conjunction with the dedicated thin-film analysis software package Stratagem and by X-ray fluorescence in its version with a micro-focus X-ray fluorescence (μ-XRF) source attached to a scanning electron microscope (SEM). Two thin-film systems have been analyzed: Fe1-xNix on silicon wafer and Si1-xGex on Al2O3 substrate, in both cases the layers being grown to a thickness of about 200 nm by ion beam sputter deposition. Samples of five different atomic fractions have been produced and analyzed for each thin-film system. Moreover, reference samples with certified elemental composition and thickness have been also available. This study is part of an interlaboratory comparison organized in the frame of standardization technical committee ISO/TC 201 “Surface chemical analysis.” Two laboratories have been analyzed by ED-EPMA (one laboratory standardless and one laboratory using both standardless and with standards variants) and one laboratory by μ-XRF (standardless and with standards). All the elemental compositions obtained with different methods are in very good agreement for the complete two sets of five samples each.
KW - Thin films
KW - Elemental composition
KW - FeNi
KW - SiGe
KW - Electron probe microanalysis
KW - X-ray Fluorescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509262
DO - https://doi.org/10.1002/sia.6834
SN - 0142-2421
VL - 52
IS - 12
SP - 929
EP - 932
PB - John Wiley & Sons Ltd
AN - OPUS4-50926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Rühle, Bastian
A1 - Kuchenbecker, Petra
A1 - Löhmann, Oliver
A1 - Lindemann, Franziska
A1 - Hodoroaba, Vasile-Dan
T1 - Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders
N2 - Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed.
KW - Nanopowder
KW - Electron microscopy
KW - Sample preparation
KW - Cross-sectioning
KW - Cerium oxide
KW - Zinc oxide
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593289
DO - https://doi.org/10.1038/s41598-023-51094-0
SN - 2045-2322
VL - 14
SP - 1
EP - 10
PB - Springer Nature
CY - London
AN - OPUS4-59328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, F.
A1 - Isopescu, R.
A1 - Pellutiè, L.
A1 - Sordello, F.
A1 - Rossi, A. M.
A1 - Ortel, Erik
A1 - Martra, G.
A1 - Hodoroaba, Vasile-Dan
A1 - Maurino, V.
T1 - Machine learning approach for elucidating and predicting the role of synthesis parameters on the shape and size of TiO2 nanoparticles
N2 - In the present work a series of design rules are developed in order to tune the morphology of TiO2 nanoparticles through hydrothermal process. Through a careful experimental design, the influence of relevant process parameters on the synthesis outcome are studied, reaching to the develop predictive models by using Machine Learning methods. The models, after the validation and training, are able to predict with high accuracy the synthesis outcome in terms of nanoparticle size, polydispersity and aspect ratio. Furthermore, they are implemented by reverse engineering approach to do the inverse process, i.e. obtain the optimal synthesis parameters given a specific product characteristic. For the first time, it is presented a synthesis method that allows continuous and precise control of NPs morphology with the possibility to tune the aspect ratio over a large range from 1.4 (perfect truncated bipyramids) to 6 (elongated nanoparticles) and the length from 20 to 140 nm.
KW - Machine learning
KW - Nanoparticles
KW - Titanium dioxide
KW - Size
KW - Shape
KW - Synthesis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515084
DO - https://doi.org/10.1038/s41598-020-75967-w
VL - 10
IS - 1
SP - 18910
PB - Springer Nature
AN - OPUS4-51508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, M.
A1 - Kömmling, Anja
A1 - Böhning, Martin
A1 - Jaunich, Matthias
T1 - Ageing of elastomers in air and in hydrogen environment - A comparative study
N2 - EPDM, HNBR and FKM materials were exposed at 150 ◦C to air under atmospheric pressure and to hydrogen at 50 bar for different ageing times. All measurements after hydrogen exposure were conducted on samples in degassed condition to assess irreversible effects resulting from that exposure and to compare them to those after ageing in air. Density, hardness, tensile properties, compression set, and hydrogen permeability of all samples were analysed. In both ageing environments, HNBR exhibited the most significant changes of material properties.
However, for both EPDM and HNBR, considerably less severe ageing effects were observed under hydrogen in comparison to ageing in air. On the other hand, FKM showed about the same low level of deterioration in both ageing environments but exhibited poor resistance against damage due to rapid gas decompression in hydrogen environment that can lead to seal failure. The obtained results may serve as a guidance toward a better understanding for design and utilisation of elastomeric materials in future hydrogen infrastructure components.
KW - Rapid gas decompression
KW - Condensed matter physics
KW - Hydrogen
KW - Sustainability and the environment
KW - Rubber sealing
KW - Renewable energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597417
DO - https://doi.org/10.1016/j.ijhydene.2024.03.053
SN - 0360-3199
SN - 1879-3487
VL - 63
SP - 207
EP - 216
PB - Elsevier
CY - Oxford
AN - OPUS4-59741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmed, R.
A1 - Vaishampayan, A.
A1 - Cuellar-Camacho, J. L.
A1 - Wight, D. J.
A1 - Donskyi, Ievgen
A1 - Unger, Wolfgang
A1 - Grohmann, E.
A1 - Haag, R.
A1 - Wagner, O.
T1 - Multivalent Bacteria Binding by Flexible Polycationic Microsheets Matching Their Surface Charge Density
N2 - Aiming at the overall negative surface charge of bacteria, a new strategy of antibacterial agents based on large polymer-modified graphene oxide (GO) sheets is assessed. The presented flexible, polycationic Sheets match the size and charge density of the Escherichia coli surface charge density (2 × 1014 cm−2). These matching parameters create an unspecific but very strong bacteria adsorber by multivalent, electrostatic attraction.
Their interaction with bacteria is visualized via atomic force and confocal microscopy and shows that they effectively bind and wrap around E. coli cells, and thereby immobilize them. The incubation of Gram-negative and -positive bacteria (E. coli and methicillin-resistant Staphylococcus aureus, MRSA) with these polycationic sheets leads to the inhibition of proliferation and a reduction of the colony forming bacteria over time.
This new type of antibacterial agent acts in a different mode of Action than classical biocides and could potentially be employed in medicinal, technical, or agriculture applications. The presented microsheets and their unspecific binding of cell interfaces could further be employed as adsorber material for bacterial filtration or immobilization for imaging, analysis, or sensor technologies.
KW - Surface charge
KW - Bacteria
KW - Graphene oxide
KW - Escherichia coli
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509651
DO - https://doi.org/10.1002/admi.201902066
VL - 7
IS - 15
SP - 1902066
PB - WILEY-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-50965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Rauscher, H.
A1 - Mech, A.
A1 - Gaillard, C.
A1 - Stintz, M.
A1 - Wohlleben, W.
A1 - Weigel, St.
A1 - Ghanem, A.
A1 - Hodoroaba, Vasile-Dan
A1 - Babick, F.
A1 - Mielke, Johannes
T1 - Recommendations on a Revision of the EC Definition of Nanomaterial Based on Analytical Possibilities
N2 - In October 2011 the European Commission (EC) published a "Recommendation on the definition of nanomaterial" (2011/696/EU), to promote consistency in the interpretation of the term "nanomaterial" for legislative and policy purposes in the EU. The EC NM Definition includes a commitment to its review in the light of experience and of scientific and technological developments. This review is ongoing in 2015 and as a contribution to the review the Joint Research Centre of the European Commission (JRC) has already developed a series of three scientific-technical reports with the title: “Towards a review of the EC Recommendation for a definition of the term nanomaterial” which provides to the EC policy services science-based options on how the definition could be revised or supported with additional guidance.
The overarching nature and wide scope of the EC NM Definition, as it does not exclude a priori any particulate material regardless the state, form and size, creates many analytical challenges in its imple-mentation for all stakeholders, including enterprises and regulators.
The NanoDefine project has as core objective to support the implementation of the EC NM Definition. In this report key aspects of the EC NM Definition are addressed, with the goal to improve the implement-ability of the EC NM Definition. These aspects are presented and discussed based on the results of two years of research performed within the framework of the project. As a result this report assesses how well the requirements of the EC NM Definition can be fulfilled with currently available analytical possi-bilities. It presents recommendations and options on a revision of the EC NM Definition to improve the implementability of the definition based on currently available analytical possibilities, according to the state of the art of mid-2015.
Of the technical issues considered in this report, the following seem to deserve the most attention in terms of clarification of the definition and/or provision of additional implementation guidance:
The term ‘external dimension’.
A clear definition of 'External dimension' should be included in the text of the EC NM definition and more precise guidance on what is considered as an external dimension and how to properly character-ise it should be provided.
The ‘number based particle size distribution‘.
The EC NM Definition uses a threshold related to the number based size distribution of particles. Yet most of the easily available techniques provide a mass-, volume- or scattered light intensity-based size distribution which needs to be converted into a number based distribution to be used for regulatory pur-poses. A specific guidance on the conditions under which these methods can be used to identify a na-nomaterial by employing appropriate quantity or metrics conversion should be provided.
The ‘polydispersity‘ and ‘upper size limit‘
Polydispersity is a challenge for the measurement of particle size distribution for the EC NM definition, specifically for materials with high polydispersity index and broad size distribution especially when the volume or mass of the fraction containing particles below 100 nm is very small. Therefore a dedicated guidance should be provided that allows applying an upper size limit in measurements and particle statistics.
KW - Nanomaterial
KW - EU Definition of nanomaterial
KW - Nanoparticles
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-432339
UR - http://www.nanodefine.eu/publications/reports/NanoDefine_TechnicalReport_D7.10.pdf
SP - 1
EP - 68
PB - The NanoDefine Consortium
CY - Wageningen, The Netherlands
AN - OPUS4-43233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sordello, F.
A1 - Prozzi, M.
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
A1 - Pellegrino, F.
T1 - Increasing the HER efficiency of photodeposited metal nanoparticles over TiO2 using controlled periodic illumination
N2 - Although the use of noble metal catalysts can increase the efficiency of hydrogen evolution reaction, the process is still limited by the characteristics of the metal-hydrogen (M−H) bond, which can be too strong or too weak, depending on the metal employed. Studies revealed that the hydrogen affinity for the metal surface (i.e. H absorption/desorption) is regulated also by the potential at the metal nanoparticles. Through controlled periodic illumination (CPI) of a series of metal/TiO2 suspensions, here we demonstrated that an increase of the HER efficiency is possible for those photodeposited metals which have a Tafel slope below 125 mV. Two possible explanations are here reported, in both of them the M−H interaction and the metal covering level play a prominent role, which also depend on the prevailing HER mechanism (Volmer-Heyrovsky or Volmer-Tafel).
KW - Controlled periodic illumination
KW - Hydrogen evolution reaction
KW - Titanium dioxide
KW - Photoreforming
KW - Volcano plot
KW - Sabatier
KW - Nanoparticles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589875
DO - https://doi.org/10.1016/j.jcat.2023.115215
VL - 429
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-58987
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Heinrich, Thomas
A1 - Tougaard, S.
A1 - Werner, W. S. M.
A1 - Hronek, M.
A1 - Kunz, Valentin
A1 - Radnik, Jörg
A1 - Stockmann, Jörg M.
A1 - Hodoroaba, Vasile-Dan
A1 - Benemann, Sigrid
A1 - Nirmalananthan-Budau, Nithiya
A1 - Geißler, Daniel
A1 - Sparnacci, K.
A1 - Unger, Wolfgang
T1 - Determining the thickness and completeness of the shell of polymer core-shell nanoparticles by X-ray photoelectron spectroscopy, secondary ion mass spectrometry, and transmission scanning electron microscopy
N2 - Core–shell nanoparticles (CSNPs) have become indispensable in various industrial applications. However, their real internal structure usually deviates from an ideal core–shell structure. To control how the particles perform with regard to their specific applications, characterization techniques are required that can distinguish an ideal from a nonideal morphology. In this work, we investigated poly(tetrafluoroethylene)–poly(methyl methacrylate) (PTFE–PMMA) and poly(tetrafluoroethylene)–polystyrene (PTFE–PS) polymer CSNPs with a constant core diameter (45 nm) but varying shell thicknesses (4–50 nm). As confirmed by transmission scanning electron microscopy (T-SEM), the shell completely covers the core for the PTFE–PMMA nanoparticles, while the encapsulation of the core by the shell material is incomplete for the PTFE–PS nanoparticles. X-ray photoelectron spectroscopy (XPS) was applied to determine the shell thickness of the nanoparticles. The software SESSA v2.0 was used to analyze the intensities of the elastic peaks, and the QUASES software package was employed to evaluate the shape of the inelastic background in the XPS survey spectra. For the first time, nanoparticle shell thicknesses are presented, which are exclusively based on the analysis of the XPS inelastic background. Furthermore, principal component analysis (PCA)-assisted time-of-flight secondary-ion mass spectrometry (ToF-SIMS) of the PTFE–PS nanoparticle sample set revealed a systematic variation among the samples and, thus, confirmed the incomplete encapsulation of the core by the shell material. As opposed to that, no variation is observed in the PCA score plots of the PTFE–PMMA nanoparticle sample set. Consequently, the complete coverage of the core by the shell material is proved by ToF-SIMS with a certainty that cannot be achieved by XPS and T-SEM.
KW - XPS
KW - T-SEM
KW - ToF-SIMS
KW - Core-shell nanoparticles
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499165
DO - https://doi.org/10.1021/acs.jpcc.9b09258
VL - 123
IS - 49
SP - 29765
EP - 29775
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-49916
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drobne, D.
A1 - Ciornii, Dmitri
A1 - Hodoroaba, Vasile-Dan
A1 - Bohmer, N.
A1 - Novak, S.
A1 - Kranjc, E.
A1 - Kononenko, V.
A1 - Reuther, R.
T1 - Knowledge, Information, and Data Readiness Levels (KaRLs) for Risk Assessment, Communication, and Governance of Nano-, New, and Other Advanced Materials
N2 - The obvious benefits derived from the increasing use of engineered nano-, new, and advanced materials and associated products have to be weighed out by a governance process against their possible risks. Differences in risk perception (beliefs about potential harm) among stakeholders, in particular nonscientists, and low transparency of the underlying decision processes can lead to a lack of support and acceptance of nano-, new, and other advanced material enabled products. To integrate scientific outcomes with stakeholders needs, this work develops a new approach comprising a nine-level, stepwise categorization and guidance system entitled “Knowledge, Information, and Data Readiness Levels” (KaRLs), analogous to the NASA Technology Readiness Levels. The KaRL system assesses the type, extent, and usability of the available data, information, and knowledge and integrates the participation of relevant and interested stakeholders in a cocreation/codesign process to improve current risk assessment, communication, and governance. The novelty of the new system is to communicate and share all available and relevant elements on material related risks in a user/stakeholder-friendly, transparent, flexible, and holistic way and so stimulate reflection, awareness, communication, and a deeper understanding that ultimately enables the discursive process that is needed for the sustainable risk governance of new materials.
KW - Risk asessment
KW - Advanced materials
KW - TRL
KW - Governance
KW - Data readiness level
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575344
DO - https://doi.org/10.1002/gch2.202200211
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-57534
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Holzweber, Markus
A1 - Unger, Wolfgang
A1 - Hodoroaba, Vasile-Dan
T1 - Ionic liquids as a reference material candidate for the quick performance check of energy dispersive X-ray spectrometers for the low energy range below 1 keV
N2 - Ionic liquids (ILs) are proposed as simple and efficient test materials to evaluate the performance of energy dispersive X-ray spectrometers (EDS) in the low energy range below 1 keV. By only one measurement, C Kα, N Kα, O Kα, and F Kα X-ray lines can be excited. Additionally, the S Kα line at 2.3 keV and, particularly, the S L series at 149 eV complete the picture with X-ray lines offered by the selected ILs. The well-known (certifiable) elemental composition of the ILs selected in the present study can be used to check the accuracy of results produced with the available EDS quantification routines in the low energy range, simultaneously, for several low atomic number elements. A comparison with other reference materials in use for testing the performance of EDS in the low energy range is included.
KW - Ionic liquids
KW - EDX
KW - CRM
KW - Reference material
KW - Low energy
KW - X-rays
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-369120
DO - https://doi.org/10.1021/acs.analchem.6b01444
SN - 0003-2700
SN - 1520-6882
VL - 88
IS - 14
SP - 6967
EP - 6970
PB - ACS Publications
CY - Columbus, Ohio
AN - OPUS4-36912
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Burr, L.
A1 - Schmid, D.
A1 - Hodoroaba, Vasile-Dan
T1 - Towards a method for quantitative evaluation of nanoparticle from suspensions via microarray printing and SEM analysis
N2 - As part of the development of a library of accurate and efficient methods for measurement of nanoparticle properties, we develop and optimize a method for the efficient analysis of nanoparticle size distribution from suspensions via microprinting and digital analysis of electron microscopy (SEM and TEM) images, with the ultimate aim of automated quantitative concentration analysis (calculated from drop volume). A series of different nanoparticle suspensions (gold, latex, and SiO2 in varying sizes and concentrations) were printed onto TEM grids in a 4 x 4 array in the concentration range 7x10^8 to 1x10^11 nanoparticles/mL and imaged with SEM. Concentrations and printing conditions (temperature, relative humidity) were varied in order to minimize the coffee-ring effect.
KW - Nanoparticles
KW - Particle size distribution
KW - Electron microscopy
KW - Microarray printing
KW - Sample preparation
KW - Nanoparticle concentration
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528455
DO - https://doi.org/10.1088/1742-6596/1953/1/012002
VL - 1953
SP - 012002
PB - IOP Publishing
AN - OPUS4-52845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Crouzier, L.
A1 - Feltin, N.
A1 - Delvallée, A.
A1 - Pellegrino, Francesco
A1 - Maurino, V.
A1 - Cios, Grzegorz
A1 - Tokarski, T.
A1 - Salzmann, Christoph
A1 - Deumer, J.
A1 - Gollwitzer, C.
A1 - Hodoroaba, Vasile-Dan
T1 - Correlative analysis of the dimensional properties of bipyramidal titania nanoparticles by complementing electron microscopy with other methods
N2 - In this paper, the accurate determination of the size and size distribution of bipyramidal anatase nanoparticles (NPs) after deposition as single particles on a silicon substrate by correlative Scanning Electron Microscopy (SEM) with Atomic Force Microscopy (AFM) analysis is described as a new measurement procedure for metrological purposes. The knowledge of the exact orientation of the NPs is a crucial step in extracting the real 3D dimensions of the particles. Two approaches are proposed to determine the geometrical orientation of individual nano‐bipyramides: (i) AFM profiling along the long bipyramid axis and (ii) stage tilting followed by SEM imaging. Furthermore, a recently developed method, Transmission Kikuchi Diffraction (TKD), which needs preparation of the crystalline NPs on electron‐transparent substrates such as TEM grids, has been tested with respect to its capability of identifying the geometrical orientation of the individual NPs. With the NPs prepared homogeneously on a TEM grid, the transmission mode in a SEM, i.e., STEM‐in‐SEM (or T‐SEM), can be also applied to extract accurate projection dimensions of the nanoparticles from the same sample area as that analysed by SEM, TKD and possibly AFM. Finally, Small Angle X‐ray Scattering (SAXS) can be used as an ensemble technique able to measure the NPs in liquid suspension and, with ab‐initio knowledge of the NP shape from the descriptive imaging techniques, to provide traceable NP size distribution and particle concentration.
KW - Nanoparticles
KW - Complex-shape
KW - Bipyramid
KW - Electron microscopy
KW - AFM
KW - Size measurements
KW - TKD
KW - STEM-in-SEM
KW - SAXS
KW - Nanoparticle concentration
KW - Correlative analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539888
DO - https://doi.org/10.3390/nano11123359
SN - 2079-4991
VL - 11
IS - 12
SP - 1
EP - 19
PB - MDPI
CY - Basel
AN - OPUS4-53988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kovacevic, E.
A1 - Strunskus, T.
A1 - Santhosh, N. M.
A1 - Zavasnik, Z.
A1 - Unger, Wolfgang
A1 - Sauvage, T.
A1 - Ammar, M.-R.
A1 - Cvelbar, U.
A1 - Berndt, J.
T1 - Thermal stability studies of plasma deposited hydrogenated carbon nitride nanostructures
N2 - Thermally stable carbon nitride nanostructures have potential applications in surface coatings and automotive fields. In this work, hydrogenated nitrogen-rich carbon nitride nanoparticles have been synthesised via low-pressure low-power plasma vapour deposition technique from methane/Nitrogen gas mixture in a dry process. Thermal stability of the initially prepared hydrogenated carbon Nitride structures has been analysed by near-edge X-ray absorption fine-structure spectroscopy (NEXAFS, insitu), Raman spectroscopy, scanning and transmission electron microscopy and nuclear reaction Analysis (NRA). Thermal studies reveal the excellent stability of the material and nitrogen-rich characteristics (N/C ratio 0.5e0.2 ± 0.01). The obtained results suggest transformation of sp3-rich as-deposited carbon Nitride into sp2-carbon phase with more graphitic features upon thermal annealing. Such in-situ thermal studies of plasma deposited carbon nitrides confirm the conversion of sp3-rich phase to sp2-rich carbon phase at the critical temperature (about 450 K), without a huge loss in nitrogen content. The analysis revealed that the material is a stable plasma deposit after this critical temperature up to >1100 K. Additionally, super hydrophilic carbon nitride nanostructure transforms into a hydrophobic surface after thermal annealing.
These thermally stable hydrophobic carbon nitride nanoparticles could be used as a promising material for the hydrophobic coatings for various applications, especially for harsh conditions.
KW - Carbon nanoparticles
KW - Hydrogenated nanostructures
KW - Plasma deposition
KW - NEXAFS
KW - Thermal annealing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536163
DO - https://doi.org/10.1016/j.carbon.2021.08.008
SN - 0008-6223
VL - 184
SP - 82
EP - 90
PB - Elsevier Ltd.
AN - OPUS4-53616
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pellegrino, Francesco
A1 - Ortel, Erik
A1 - Mielke, Johannes
A1 - Schmidt, R.
A1 - Maurino, V.
A1 - Hodoroaba, Vasile-Dan
T1 - Customizing New Titanium Dioxide Nanoparticles with Controlled Particle Size and Shape Distribution: A Feasibility Study Toward Reference Materials for Quality Assurance of Nonspherical Nanoparticle Characterization
N2 - An overview is given on the synthesis of TiO2 nanoparticles with well-defined nonspherical shapes (platelet like, bipyramidal, and elongated), with the focus on controlled, reproducible synthesis, as a key requirement for the production of reference materials with homogeneous and stable properties. Particularly with regard to the nanoparticle shapes, there is a high need of certified materials,
solely one material of this type being commercially available since a few months (elongated TiO2). Further, measurement approaches with electron microscopy as the golden method to tackle the nanoparticle shape are developed to determine accurately the size and shape distribution for such nonspherical particles. A prerequisite for accurate and easy (i.e., automated) image analysis is the sample preparation, which ideally must ensure a deposition of the nanoparticles from liquid suspension onto a substrate such that the particles do not overlap, are solvent-free, and have a high deposition density. Challenges in the Synthesis of perfectly monodispersed and solvent-free TiO2 nanoparticles of platelet and acicular shapes are highlighted as well as successful measurement approaches on how to extract from 2D projection electron micrographs the most accurate spatial information, that is, true 3D size, for example, of the bipyramidal nanoparticles with different geometrical orientations on a substrate.
KW - Nanoparticles
KW - Titanium dioxide
KW - Reference materials
KW - Standardisation
KW - Particle size and shape distribution
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538849
DO - https://doi.org/10.1002/adem.202101347
VL - 24
IS - 6
SP - 1
EP - 10
PB - Wiley-VCH
AN - OPUS4-53884
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dhamo, Lorena
A1 - Carulli, F.
A1 - Nickl, Philip
A1 - Wegner, Karl David
A1 - Hodoroaba, Vasile-Dan
A1 - Würth, Christian
A1 - Brovelli, S.
A1 - Resch-Genger, Ute
T1 - Efficient luminescent solar concentrators based on environmentally friendly Cd-free ternary AIS/ZnS quantum dots
N2 - Luminescent solar concentrators (LSC) allow to obtain renewable energy from building integrated photovoltaic systems. As promising efficient and long-term stable LSC fluorophores semiconductor nanocrystals like Quantum dots (QDs) with size and composition tunable optoelectronic properties have recently emerged. The most popular II/VI or IV/VI semiconductor QDs contain, however, potentially hazardous cadmium or lead ions, which is a bottleneck for commercial applications. A simple aqueous based, microwaveassisted synthesis for environmentally friendly and highly emissive AgInS2/ ZnS QDs is developed using 3-mercaptopropionic acid (MPA) and glutathione (GSH) and their incorporation into polylaurylmethacrylate (PLMA) polymer slabs integrable in LSC devices (10.4 × 10.4 × 0.2 cm3, G = 12.98).
With this simple approach, optical power efficiencies (OPE) of 3.8% and 3.6% and optical quantum efficiencies (OQE) of 24.1% and 27.4% are obtained, which are among the highest values yet reported.
KW - Solar energy
KW - Solar concentrator
KW - Quantum dots
KW - Advanced material
KW - Quantum yield
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529735
DO - https://doi.org/10.1002/adom.202100587
SN - 2195-1071
SN - 0935-9648
VL - 9
IS - 17
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-52973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sachse, René
A1 - Hodoroaba, Vasile-Dan
A1 - Kraehnert, R.
A1 - Hertwig, Andreas
T1 - Multilevel effective material approximation for modeling ellipsometric measurements on complex porous thin films
N2 - Catalysts are important components in chemical processes because they lower the activation energy and thus determine the rate, efficiency and selectivity of a chemical reaction. This property plays an important role in many of today’s processes, including the electrochemical splitting of water. Due to the continuous development of catalyst materials, they are becoming more complex, which makes a reliable evaluation of physicochemical properties challenging even for modern analytical measurement techniques and industrial manufacturing.
We present a fast, vacuum-free and non-destructive analytical approach using multi-sample spectroscopic ellipsometry to determine relevant material parameters such as film thickness, porosity and composition of mesoporous IrOx–TiOy films. Mesoporous IrOx–TiOy films were deposited on Si wafers by sol–gel synthesis, varying the composition of the mixed oxide films between 0 and 100 wt%Ir. The ellipsometric modeling is based on an anisotropic Bruggeman effective medium approximation (a-BEMA) to determine the film thickness and volume fraction of the material and pores. The volume fraction of the material was again modeled using a Bruggeman EMA to determine the chemical composition of the materials. The ellipsometric fitting results were compared with complementary methods, such as scanning electron microscopy (SEM), electron probe microanalysis (EPMA) as well as environmental ellipsometric porosimetry (EEP).
KW - Electrochemical catalysts
KW - Mixed metal oxide
KW - Multi-sample analysis
KW - Spectroscopic ellipsometry
KW - Thin mesoporous films
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551026
DO - https://doi.org/10.1515/aot-2022-0007
SN - 2192-8584
SN - 2192-8576
VL - 11
IS - 3-4 (Topical issue: Ellipsometry)
SP - 137
EP - 147
PB - De Gruyter
CY - Berlin
AN - OPUS4-55102
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brüngel, R.
A1 - Rückert, J.
A1 - Müller, P.
A1 - Babick, F.
A1 - Friedrich, C. M.
A1 - Ghanem, A.
A1 - Hodoroaba, Vasile-Dan
A1 - Mech, A.
A1 - Weigel, S.
A1 - Wohlleben, W.
A1 - Rauscher, H.
T1 - NanoDefiner Framework and e-Tool Revisited According to the European Commission’s Nanomaterial Definition 2022/C 229/01
N2 - The new recommended definition of a nanomaterial, 2022/C 229/01, adopted by the European Commission in 2022, will have a considerable impact on European Union legislation addressing chemicals, and therefore tools to implement this new definition are urgently needed. The updated NanoDefiner framework and its e-tool implementation presented here are such instruments, which help stakeholders to find out in a straightforward way whether a material is a nanomaterial or not. They are two major outcomes of the NanoDefine project, which is explicitly referred to in the new definition. This work revisits the framework and e-tool, and elaborates necessary adjustments to make these outcomes applicable for the updated recommendation. A broad set of case studies on representative materials confirms the validity of these adjustments. To further foster the sustainability and applicability of the framework and e-tool, measures for the FAIRification of expert knowledge within the e-tool’s knowledge base are elaborated as well. The updated framework and e-tool are now ready to be used in line with the updated recommendation. The presented approach may serve as an example for reviewing existing guidance and tools developed for the previous definition 2011/696/EU, particularly those adopting NanoDefine project outcomes.
KW - Nanomaterial definition
KW - Nanomaterial categorisation
KW - Nanomaterial regulation
KW - Nanomaterial legislation
KW - Decision support
KW - FAIRification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571618
DO - https://doi.org/10.3390/nano13060990
SN - 2079-4991
VL - 13
IS - 6 - Special Issue "Identification and Quantification of Nanomaterials"
SP - 1
EP - 16
PB - MDPI
CY - Basel, CH
AN - OPUS4-57161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Understanding the recovery behaviour and the degradative processes of EPDM during ageing
N2 - Recovery is an important measure for seal applications representing to which extent the elastomer regains its initial shape after deformation and release of an applied force. Compression set (CS) indicates the degree of recovery. Ethylene propylene diene rubber (EPDM) was aged at 75 ◦C, 100 ◦C, 125 ◦C and 150 ◦C for different ageing times up to five years and compression set measurements were performed at different times after disassembly and after additional tempering. Short- and long-term recovery up to one year after release for samples aged at 125 ◦C and 150 ◦C was also studied. To assess the curvature in the Arrhenius diagram that may occur due to non-sufficiently aged specimens, a degradation-rate based model was fitted to the CS data after tempering. For each ageing temperature, two decay fit functions were proposed, each with an activation energy and a corresponding degradative process. The influence of ageing on the leak-tightness after fast small partial release is investigated and estimated through the analysis of the shift factors from time temperature superposition (TTS) of CS measurements at different times after disassembly. Shift factors of CS measurement after 1 s and after additional tempering are in good agreement.
KW - Compression set
KW - Ageing
KW - Recovery
KW - Degradative processes
KW - Leakage rate
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573699
DO - https://doi.org/10.1016/j.polymertesting.2023.107987
SN - 0142-9418
VL - 121
SP - 107987
PB - Elsevier Ltd.
AN - OPUS4-57369
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hesse, R.
A1 - Denecke, R.
A1 - Radnik, Jörg
T1 - Testing and validating the improved estimation of the spectrometer-transmission function with UNIFIT 2022
N2 - Recent developments of X-ray photoelectron spectroscopy using excitation energies different from the usual lab-sources Mg Kα and Al Kα, thus covering larger and different kinetic energy ranges, require more flexible approaches for determining the transmission function than the well-established ones using reference spectra. Therefore, the approach using quantified peak areas (QPA) was refined allowing a more precise estimation of the transmission function. This refinement was tested by comparing the results obtained with the new version with former calculations. Furthermore, the obtained transmission function was validated by comparing the results with a transmission function using the reference spectrum of polyethylene. Additionally, an ionic liquid was used as reference for estimating the transmission function at the energy resolved HE-SGM beamline at BESSY II. Comparison between the measured and stoichiometric composition shows that a transmission function was determined, which allows a reasonable quantification.
KW - XPS
KW - Quantification
KW - Software UNIFIT 2022
KW - Synchrotron radiation
KW - Transmission function IERF
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551671
DO - https://doi.org/10.1002/sia.7131
SN - 0142-2421
SP - 1
EP - 7
PB - Wiley-VCH
AN - OPUS4-55167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Oxidative ageing of elastomers: Experiment and modelling
N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of 125∘C and 150∘C. To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments.
KW - Compression stress relaxation
KW - Compression set
KW - IRHD microhardness
KW - Modelling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545910
DO - https://doi.org/10.1007/s00161-022-01093-9
SN - 1432-0959
SP - 1
EP - 9
PB - Springer
CY - Berlin
AN - OPUS4-54591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Babick, F.
A1 - Mielke, Johannes
A1 - Hodoroaba, Vasile-Dan
A1 - Weigel, St.
A1 - Wohlleben, W.
T1 - Critical review manuscript with real-world performance data for counting, ensemble and separating methods including in-build mathematical conversion to number distributions submitted for publication
N2 - The content of the paper is the assessment of the performance of (conventional) measurement techniques (MTs)with respect to the classification of disperse materials according to the EC recommendation for a definition of nanomaterial. This performance essentially refers to the accurate assessment of the number weighted median of (the constituent) particles. All data and conclusions are based on the analytical study conducted as real-world performance testing.
It comprised different types of MTs (imaging, counting, fractionating, spectroscopic and integral) as well as different types of materials. Beside reference materials with well-defined size distribution the study also included several commercial powders (variation of particle composition, morphology, coating, size range and polydispersity). In order to ensure comparability of measurement results, the participants were guided to use uniform protocols in sample preparation, conducting measurements, data analysis and in reporting results. Corresponding documents have been made public, in order to support the reviewing process of the paper, respectively to ensure the reproducibility of data by other users under the same conditions.
The scientific paper relies on a comprehensive set of revised measurement data reported in uniform templates, completely describes the experimental procedures and discusses the MTs’ performance for selected materials in detail. Even more, the study is summarised and evaluated, which leads to recommendations for the use of MTs within a tiered approach of NM characterisation. In addition, the paper critically examines the factors that may affect the outcome of such a comparison among different MTs.
KW - Nanomaterial
KW - Measurement techniques
KW - EC definition of nanomaterial
KW - Nanoparticles
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389646
UR - http://www.nanodefine.eu/index.php/downloads/nanodefine-technical-reports
UR - http://www.nanodefine.eu/publications/reports/NanoDefine_TechnicalReport_D3.3.pdf
SP - D3.3, 1
EP - 72
PB - The NanoDefine Consortium
CY - Wageningen, The Netherlands
AN - OPUS4-38964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Hodoroaba, Vasile-Dan
A1 - Mielke, Johannes
T1 - Templates for nanomaterial characterisation of tier 1 and tier 2 measurement methods
N2 - The EU FP7 NanoDefine project was launched in November 2013 and will run until October 2017. The Project is dedicated to support the implementation of the EU Recommendation on the Definition of Nanomaterial
by the provision of the required analytical tools and respective guidance. Main goal is to develop a novel
tiered approach consisting of (i) rapid and cost-efficient screening methods and (ii) confirmatory measurement
methods. The "NanoDefiner" eTool will guide potential end-users, such as concerned industries and regulatory bodies as well as enforcement and contract laboratories, to reliably classify if a material is nano or not. To achieve this objective, a comprehensive inter-laboratory evaluation of the performance of current
characterisation techniques, instruments and software is performed. Instruments, software and methods are
further developed. Their capacity to reliably measure the size of particulates in the size range 1-100 nm and
above (according to the EU definition) is validated. Technical reports on project results are published to
reach out to relevant stakeholders, such as policy makers, regulators, industries and the wider scientific community, to present and discuss our goals and results, to ensure a continuous exchange of views,
needs and experiences obtained from different fields of expertise and application, and to finally integrate the resulting feedback into our ongoing work on the size-related classification of nanomaterials.
KW - Nanomaterial
KW - Measurement method
KW - Screening methods
KW - Confirmatory methods
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389827
UR - http://www.nanodefine.eu/index.php/downloads/nanodefine-technical-reports
SP - 1
EP - 74
PB - The NanoDefine Consortium
CY - Wageningen, The Netherlands
AN - OPUS4-38982
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iannarelli, L.
A1 - Giovannozzi, A. M.
A1 - Morelli, F.
A1 - Viscotti, F.
A1 - Bigini, P.
A1 - Maurino, V.
A1 - Spotto, G.
A1 - Martra, G.
A1 - Ortel, Erik
A1 - Hodoroaba, Vasile-Dan
A1 - Rossi, A. M.
A1 - Diomede, L.
T1 - Shape engineered TiO2 nanoparticles in Caenorhabditis elegans: a Raman imaging based approach to assist tissue-specific toxicological studies
N2 - Titanium dioxide (TiO₂) nanoparticles (NPs) are one of the main sources of the nanoparticulate matter to which humans are directly exposed and several studies have demonstrated their potential toxic effects. The in vivo detailed spatial distribution of TiO₂ NPs is investigated herein for the first time, using a 2D chemical imaging analysis based on confocal Raman spectroscopy. The invertebrate nematode C. elegans was employed as a prototypical model of living organisms. Rod, bipyramidal and quasispherical engineered TiO₂ NPs with different primary particle sizes and agglomeration states were prepared, characterized and then administered to nematodes. Exploiting the typical fingerprint of TiO₂ in the Raman spectrum, we monitored the biodistribution of NPs inside the worm using a non-invasive, label-free method. The high spatial resolution chemical imaging and the specificity of the Raman technique in the localization of TiO₂ NPs helped in the design of behavioral C. elegans studies aimed at elucidating the relationship among the size, shape, and agglomeration state of NPs and their ability to induce specific toxic effects. Rod-shaped NPs were the most toxic, greatly impairing pharyngeal function, reproduction and larval growth; this indicates that the rod shape, more than the bipyramidal and spherical shapes, enables NPs to interact with biological systems. These findings indicate that this Raman-nematode combined approach represents a step forward in the field of detection of NPs in living organisms, and being rapid and inexpensive enough, it can be applied as the first screening for the ability of NPs to biodistribute and exert toxicological properties in vivo.
KW - Titanium dioxide
KW - Nanoparticles
KW - Caenorhabdtis elegans
KW - Micro-Raman imaging
KW - Nanotoxicology
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-369695
UR - http://pubs.rsc.org/en/content/articlelanding/2016/ra/c6ra09686g#!divAbstract
DO - https://doi.org/10.1039/c6ra09686g
SN - 2046-2069
VL - 6
SP - 70501
EP - 70509
PB - Royal Society of Chemistry
CY - Thomas Graham House, Cambridge
AN - OPUS4-36969
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hodoroaba, Vasile-Dan
A1 - Akcakayiran, D.
A1 - Grigoriev, D.O.
A1 - Shchukin, D.G.
T1 - Characterization of micro- and nanocapsules for self-heating anti-corrosion coatings by high-resolution SEM with coupled transmission mode and EDX
N2 - The observation of morphological details down to the nanometer range of the outer surface of micro-, submicro- and nanoparticles in a high-resolution scanning electron microscope (SEM) was extended with in-depth observation by enabling the transmission mode in the SEM, i.e. TSEM. The micro- and nanocapsules characterized in this study were fabricated as depots for protective agents to be embedded in innovative self-healing coatings. By combining the two imaging modes (upper and in-depth observation) complementing each other a better characterisation by a more comprehensive interpretation of the 'consistency' of the challenging specimens, e.g. including details 'hidden' beyond the surface or the real specimen shape at all, has been attained. Furthermore, the preparation of the quasi electron transparent samples onto thin supporting foils enables also elemental imaging by energy dispersive X-ray spectroscopy (EDX) with high spatial resolution. Valuable information on the elemental distribution in individual micro-, submicro- and even nanocapsules completes the '3D' high resolution morphological characterization at the same multimodal SEM/TSEM/EDX system.
KW - Scanning electron microscopy (SEM)
KW - High-resolution transmission in SEM (TSEM)
KW - Energy dispersive X-ray spectroscopy (EDX)
KW - Micro- and nanocapsules
KW - Anti-corrosion coatings
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304201
DO - https://doi.org/10.1039/c3an01717f
SN - 0003-2654
SN - 1364-5528
VL - 139
IS - 8
SP - 2004
EP - 2010
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-30420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beckmann, Jörg
A1 - von der Ehe, Kerstin
A1 - Jaunich, Matthias
A1 - Schade, U.
A1 - Aziz, E. F.
A1 - Wolff, Dietmar
T1 - Fourier-spektroskopische Untersuchungen im mittleren- und fernen Infrarotbereich an Co-60 bestrahlten und thermisch belasteten ultrahochmolekularen Polyethylen-Proben
N2 - Fourier-Spektroskopische Untersuchungen von hochmolekularem Polyethylen (HMW-PE) und ultrahochmolekularem Polyethylen (UHMW-PE) im Mittleren - und Fernen Infrarotbereich können Veränderungen der molekularen Strukturen nachweisen, die durch Co60 γ-Strahlung und Rekristallisationsprozesse initiiert werden. UHMW-PE und HMW-PE sind im gewählten IR-Bereich unterscheidbar. Die integrale Absorption der B1u – Gitterschwingungen im Fernen Infrarotbereich (THz-Bereich) ermöglichen die quantitative Beschreibung des Kristallinitätsgrades und dessen Abbau. Die Bildung ungesättigter Vinylengruppen und der Abbau ungesättigter Methylengruppen können im Mittleren Infrarotbereich nachgewiesen werden.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Infrared and far-infrared spectroscopy
KW - Polyethylene
KW - Co-60 irradiation
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313317
SN - 978-3-940283-61-0
VL - 148
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31331
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mech, A.
A1 - Wohlleben, W.
A1 - Ghanem, A.
A1 - Hodoroaba, Vasile-Dan
A1 - Weigel, S.
A1 - Babick, F.
A1 - Brüngel, R.
A1 - Friedrich, C. M.
A1 - Rasmussen, K.
A1 - Rauscher, H.
T1 - Nano or Not Nano? A Structured Approach for Identifying Nanomaterials According to the European Commission’s Definition
N2 - Identifying nanomaterials (NMs) according to European Union Legislation is challenging, as there is an enormous variety of materials, with different physico-chemical properties. The NanoDefiner Framework and its Decision Support Flow Scheme (DSFS) allow choosing the optimal method to measure the particle size distribution by matching the material properties and the performance of the particular measurement techniques. The DSFS leads to a reliable and economic decision whether a material is an NM or not based on scientific criteria and respecting regulatory requirements. The DSFS starts beyond regulatory requirements by identifying non-NMs by a proxy Approach based on their volume-specific surface area. In a second step, it identifies NMs. The DSFS is tested on real-world materials and is implemented in an e-tool. The DSFS is compared with a decision flowchart of the European Commission’s (EC) Joint Research Centre (JRC), which rigorously follows the explicit criteria of the EC NM definition with the focus on identifying NMs, and non-NMs are identified by exclusion. The two approaches build on the same scientific basis and measurement methods, but start from opposite ends: the JRC Flowchart starts by identifying NMs, whereas the NanoDefiner Framework first identifies non-NMs.
KW - Classification
KW - Definition
KW - Identification
KW - Nanomaterials
KW - Particle size
KW - Regulation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510917
DO - https://doi.org/10.1002/smll.202002228
SN - 1613-6829
SP - 2002228-1
EP - 2002228-16
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-51091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rühle, Bastian
A1 - Krumrey, Julian Frederic
A1 - Hodoroaba, Vasile-Dan
T1 - Workflow towards automated segmentation of agglomerated, non‑spherical particles from electron microscopy images using artificial neural networks
N2 - We present a workflow for obtaining fully trained artificial neural networks that can perform automatic particle segmentations of agglomerated, non-spherical nanoparticles from scanning electron microscopy images “from scratch”, without the need for large training data sets of manually annotated images. The whole process only requires about 15 minutes of hands-on time by a user and can typically be finished within less than 12 hours when training on a single graphics card (GPU). After training, SEM image analysis can be carried out by the artificial neural network within seconds. This is achieved by using unsupervised learning for most of the training dataset generation, making heavy use of generative adversarial networks and especially unpaired image-to-image translation via cycle-consistent adversarial networks. We compare the segmentation masks obtained with our suggested workflow qualitatively and quantitatively to state-of-the-art methods using various metrics. Finally, we used the segmentation masks for automatically extracting particle size distributions from the SEM images of TiO2 particles, which were in excellent agreement with particle size distributions obtained manually but could be obtained in a fraction of the time.
KW - Electron microscopy
KW - Neural networks
KW - Artificial intelligence
KW - Image segmentation
KW - Automated image analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522454
DO - https://doi.org/10.1038/s41598-021-84287-6
VL - 11
IS - 1
SP - 4942
PB - Springer Nature
AN - OPUS4-52245
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Pourmand, P.
A1 - Wolff, Dietmar
A1 - Hedenqvist, M.
T1 - Analysis of O-ring seal failure under static conditions and determination of end-of-lifetime criterion
N2 - Determining a suitable and reliable end-of-lifetime criterion for O-ring seals is an important issue for long-term seal applications. Therefore, seal failure of ethylene propylene diene rubber (EPDM) and hydrogenated nitrile butadiene rubber (HNBR) O-rings aged in the compressed state at 125 °C and at 150 °C for up to 1.5 years was analyzed and investigated under static conditions, using both non-lubricated and lubricated seals. Changes of the material properties were analyzed with dynamic-mechanical analysis and permeability experiments. Indenter modulus measurements were used to investigate DLO effects. It became clear that O-rings can remain leak-tight under static conditions even when material properties have already degraded considerably, especially when adhesion effects are encountered. As a feasible and reliable end-of-lifetime criterion for O-ring seals under static conditions should include a safety margin for slight dimensional changes, a modified leakage test involving a small and rapid partial decompression of the seal was introduced that enabled determining a more realistic but still conservative end-of-lifetime criterion for an EPDM seal.
KW - EPDM
KW - HNBR
KW - Seal failure
KW - Leak-tightness
KW - DLO
KW - Oxygen permability
KW - DMA
KW - Indenter modulus
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486125
DO - https://doi.org/10.3390/polym11081251
SN - 2073-4360
VL - 11
IS - 8
SP - 1251, 1
EP - 19
PB - MDPI
CY - Basel, CH
AN - OPUS4-48612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trajkovski, B.
A1 - Jaunich, Matthias
A1 - Müller, W.
A1 - Beuer, F.
A1 - Zafiropoulos, G.
A1 - Houshmand, A.
ED - Eppel, S.J.
T1 - Hydrophilicity, viscoelastic, and physicochemical properties variations in dental bone grafting substitutes
N2 - The indication-oriented Dental Bone Graft Substitutes (DBGS) selection, the correct bone defects classification, and appropriate treatment planning are very crucial for obtaining successful clinical results. However, hydrophilic, viscoelastic, and physicochemical properties’ influence on the DBGS regenerative potential has poorly been studied. For that reason, we investigated the dimensional changes and molecular mobility by Dynamic Mechanical Analysis (DMA) of xenograft (cerabone®), synthetic (maxresorb®), and allograft (maxgraft®, Puros®) blocks in a wet and dry state. While no significant differences could be seen in dry state, cerabone® and maxresorb® blocks showed a slight height decrease in wet state, whereas both maxgraft® and Puros® had an almost identical height increase. In addition, cerabone® and maxresorb® blocks remained highly rigid and their damping behaviour was not influenced by the water. On the other hand, both maxgraft® and Puros® had a strong increase in their molecular mobility with different damping behaviour profiles during the wet state. A high-speed microscopical imaging system was used to analyze the hydrophilicity in several naturally derived (cerabone®, Bio-Oss®, NuOss®, SIC® nature graft) and synthetic DBGS granules (maxresorb®, BoneCeramic®, NanoBone®, Ceros®). The highest level of hydrophilicity was detected in cerabone® and maxresorb®, while Bio-Oss® and BoneCeramic® had the lowest level of hydrophilicity among both naturally derived and synthetic DBGS groups. Deviations among the DBGS were also addressed via physicochemical differences recorded by Micro Computed Tomography, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, X-ray powder Diffractometry, and Thermogravimetric Analysis. Such DBGS variations could influence the volume stability at the grafting site, handling as well as the speed of vascularization and bone regeneration. Therefore, this study initiates a new insight into the DBGS differences and their importance for successful clinical results.
KW - Biomaterials
KW - Bone grafting
KW - Bone substitutes
KW - Hydrophilicity
KW - Mechanical analysis
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-439890
DO - https://doi.org/10.3390/ma11020215
SN - 1996-1944
VL - 11
IS - 2
SP - Article 215, 1
EP - 19
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-43989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lisec, Jan
A1 - Jaeger, Carsten
A1 - Rashid, R.
A1 - Munir, R.
A1 - Zaidi, N.
T1 - Cancer cell lipid class homeostasis is altered under nutrient-deprivation but stable under hypoxia
N2 - Background: Cancer cells modify the balance between fatty acid (FA) synthesis and uptake under metabolic stress, induced by oxygen/nutrient deprivation. These modifications were shown to alter the levels of individual triglyceride (TG) or phospholipid sub-species. To attain a holistic overview of the lipidomic profiles of cancer cells under stress we performed a broad lipidomic assay, comprising 244 lipids from six major classes. This assay allowed us to perform robust analyses and assess the changes in averages of broader lipid-classes, stratified on the basis of saturation index of their fatty-acyl side chains.
Methods: Global lipidomic profiling using Liquid Chromatography-Mass Spectrometry was performed to assess lipidomic profiles of biologically diverse cancer cell lines cultivated under metabolically stressed conditions.
Results: Neutral lipid compositions were markedly modified under serum-deprived conditions and, strikingly, the cellular level of triglyceride subspecies decreased with increasing number of double bonds in their fatty acyl chains.
In contrast and unexpectedly, no robust changes were observed in lipidomic profiles of hypoxic (2% O2) cancer cells despite concurrent changes in proliferation rates and metabolic gene expression.
Conclusions: Serum-deprivation significantly affects lipidomic profiles of cancer cells. Although, the levels of individual lipid moieties alter under hypoxia (2% O2), the robust averages of broader lipid classes remain unchanged.
KW - Tumor metabolism
KW - Fatty acid metabolism
KW - Lipidomic profile
KW - Metabolic stress
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483186
DO - https://doi.org/10.1186/s12885-019-5733-y
SN - 1471-2407
VL - 19
SP - 501
PB - Springer Nature
CY - Berlin
AN - OPUS4-48318
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Munsch, Sarah Mandy
A1 - Strangfeld, Christoph
A1 - Kruschwitz, Sabine
ED - Kärger, J.
ED - Heitjans, P.
T1 - Determining the pore size distribution in synthetic and building materials using 1D NMR
N2 - NMR is gaining increasing interest in civil engineering applications for the use of microstructure characterization as e.g. pore size determination and monitoring of moisture transport in porous materials. In this study, the use of NMR as a tool for pore size characterization was investigated. For our study we used screed and synthetic materials at partial and full saturation. A successful determination could be achieved when having a reference or calibration method, although partly diffusion effects have been registered. Due to these diffusion effects, for the determination of pore size distributions of synthetic materials another NMR device was needed. Finally, the determination of the surface relaxivity of screed (50 μm/s) led to a higher value than first expected from literature.
T2 - 14th International Bologna Conference on Magnetic Resonance in Porous Media
CY - Gainesville, FL, USA
DA - 18.02.2018
KW - NMR relaxometry
KW - Pore size distribution
KW - Building materials
KW - Porous materials
KW - Surface relaxivity
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483680
UR - https://diffusion.uni-leipzig.de/pdf/volume31/diff_fund_31(2019)02.pdf
SN - 1862-4138
N1 - Geburtsname von Munsch, Sarah Mandy: Nagel, S. M. - Birth name of Munsch, Sarah Mandy: Nagel, S. M.
VL - 31
IS - 2
SP - 1
EP - 9
PB - University of Leipzig
CY - Leipzig
AN - OPUS4-48368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steger, Simon
A1 - Oesterle, D.
A1 - Bretz, S.
A1 - Frenzel, L.
A1 - Stege, H.
A1 - Winkelmeyer, I.
A1 - Hahn, Oliver
A1 - Geiger, G.
T1 - Kandinsky’s fragile art: a multidisciplinary investigation of four early reverse glass paintings (1911–1914) by Wassily Kandinsky
N2 - This work highlights the rediscovery of the technique of reverse glass painting by the artists of the “Blaue Reiter” collective in the early 20th-century and focusses particularly on the role of Wassily Kandinsky (1866–1944). Kandinsky created more than 70 reverse paintings on glass and showed several of them in exhibitions together with paintings on canvas and cardboard, implying a coequal importance of these techniques. Four of his early (1911–1914) reverse glass paintings (Auferstehung, Allerheiligen II, Rudern, Apokalyptischer Reiter II) were selected for investigation and their iconography, painting techniques and painting materials were examined. Two paintings were executed on so-called cathedral glass, revealing a “hammered surface”, whereas Kandinsky used a corrugated glass panel for Rudern. A multi-analytical, non-invasive approach [X-ray fluorescence (XRF), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), VIS spectroscopy (VIS), Raman spectroscopy] was taken to identify the pigments and classify the binding media. The results reveal a broad palette of materials. Several pigments like lead white, zinc white, Strontium yellow, Prussian blue, viridian, cadmium yellow, ultramarine blue, cinnabar and carbon black were found in most of the four paintings. The use of the rare synthetic organic pigments PR60 and PB52 is discussed. In two works of art, cadmium carbonate is associated with cadmium yellow. The identification of aluminium foil along with tin foils in Rudern indicates an early use of this material for reverse glass paintings.
KW - Reverse glass painting
KW - Non-invasive analysis
KW - Raman spectroscopy
KW - DRIFTS
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480075
DO - https://doi.org/10.1186/s40494-019-0268-8
VL - 7
IS - 27
SP - 1
EP - 17
PB - Springer
AN - OPUS4-48007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Kun
A1 - Carrod, Andrew J.
A1 - Del Giorgio, Elena
A1 - Hughes, Joseph
A1 - Rurack, Knut
A1 - Bennet, Francesca
A1 - Hodoroaba, Vasile-Dan
A1 - Harrad, Stuart
A1 - Pikramenou, Zoe
T1 - Luminescence Lifetime-Based Sensing Platform Based on Cyclometalated Iridium(III) Complexes for the Detection of Perfluorooctanoic Acid in Aqueous Samples
N2 - Luminescence lifetimes are an attractive analytical method for detection due to its high sensitivity and stability. Iridium probes exhibit luminescence with long excited-state lifetimes, which are sensitive to the local environment. Perfluorooctanoic acid (PFOA) is listed as a chemical of high concern regarding its toxicity and is classified as a “forever chemical”. In addition to strict limits on the presence of PFOA in drinking water, environmental contamination from industrial effluent or chemical spills requires rapid, simple, accurate, and cost-effective analysis in order to aid containment. Herein, we report the fabrication and function of a novel and facile luminescence sensor for PFOA based on iridium modified on gold surfaces. These surfaces were modified with lipophilic iridium complexes bearing alkyl chains, namely, IrC6 and IrC12, and Zonyl-FSA surfactant. Upon addition of PFOA, the modified surfaces IrC6-FSA@Au and IrC12-FSA @Au show the largest change in the red luminescence signal with changes in the luminescence lifetime that allow monitoring of PFOA concentrations in aqueous solutions. The platform was tested for the measurement of PFOA in aqueous samples spiked with known concentrations of PFOA and demonstrated the capacity to determine PFOA at concentrations >100 μg/L (240 nM).
KW - Perfluorooctanoic Acid (PFOA)
KW - Cyclometalated iridium (III) complexes
KW - Luminescent lifetime
KW - Optically active surfaces
KW - ToF-SIMS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594535
UR - https://pubs.acs.org/doi/10.1021/acs.analchem.3c04289
DO - https://doi.org/10.1021/acs.analchem.3c04289
VL - 96
IS - 4
SP - 1565
EP - 1575
PB - American Chemical Society (ACS)
AN - OPUS4-59453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Carl, Peter
A1 - Ramos, Inês I.
A1 - Segundo, Marcela A.
A1 - Schneider, Rudolf
T1 - Antibody conjugation to carboxyl-modified microspheres through N-hydroxysuccinimide chemistry for automated immunoassay applications: A general procedure
N2 - Immunochemical techniques are the workhorse for sample enrichment and detection of a large variety of analytes. In contrast to classical microtiter plate-based assays, microparticles are a next generation solid support, as they promote automation of immunoassays using flow-based techniques. Antibody immobilization is a crucial step, as these reagentsmare expensive, and inefficient coupling can result in low sensitivities. This paper proposes a general procedure for efficient immobilization of antibodies onto TentaGel particles, via Nhydroxysuccinimide chemistry. The goal was the preparation of solid supports with optimum immunorecognition, while increasing the sustainability of the process. The influence of buffer composition, activation and coupling time, as well as the amount of antibody on the immobilization efficiency was investigated, resorting to fluorophore-labeled proteins and fluorescence imaging. Buffer pH and activation time are the most important parameters for efficient coupling. It is demonstrated, that the hydrolysis of N-hydroxysuccinimide esters occurs at similar rates as in solution, limiting the utilizable time for coupling. Finally, applicability of the generated material for automated affinity extraction is demonstrated on the mesofluidic platform lab-on-valve.
KW - Mesofluidics
KW - Bead injections
KW - ELISA
KW - Carbamazepine
KW - Biomarkers
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483919
DO - https://doi.org/10.1371/journal.pone.0218686
SN - 1932-6203
VL - 14
IS - 6
SP - e0218686, 1
EP - 18
PB - Public Library of Science
CY - San Francisco, California, USA
AN - OPUS4-48391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Genath, A.
A1 - Hofmann, Michael
A1 - Tiebe, Carlo
A1 - Einspanier, R.
T1 - Proof-of-concept trial of the portable electronic nose PEN3 for detection of formic acid concentration in the beehive
N2 - Formic acid (FA) treatment as measure against the ectoparasitic mite, Varroa destructor, which infests the western honey bee, Apis mellifera, is usually performed twice a year. Although the therapeutic index is very narrow and the success of FA-treatment is highly dependent on various external factors, little is known about the local FA concentrations occuring in the hive. In this study we examined whether a commercially available odour measuring device (“electronic nose”) is suitable for measurements of high FA concentrations, as present during treatment. As measuring systems, two different setups were prepared for detection of FA concentrations in gas mixtures: A polymethyl methacrylate (PMMA) box was used to investigate whether the electronic nose is able to distinguish between different FA concentrations and a two-storied Segeberger hive to test under realistic conditions during bee-keeping.
In both experimental systems, the signals from the same sensor components (sensor type no. 1, 6, 7, 8 and 9) showed an increased sensitivity towards the presence of FA in the gas mixture. Principle component analysis (PCA) and linear discriminant analysis (LDA) allowed for identification of specific patterns in the measurement signals and showed clear correlations between the signals and the present FA concentration. These results indicate that the introduced commercial multi gas sensor system is suitable for detection of high FA concentrations, and therefore could be a starting point developing a detection method of FA. The future aim is to successfully monitor the efficiency and effectiveness of this anti-varroa-treatment.
T2 - 20. GMA/ITG-Fachtagung Sensoren und Messsysteme 2019
CY - Nuremberg, Germany
DA - 25.06.2019
KW - Apis mellifera
KW - Varroa destructor
KW - Formic Acid
KW - Metal-Oxide Gas Sensor Array
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483812
UR - https://www.ama-science.org/proceedings/details/3430
DO - https://doi.org/10.5162/sensoren2019/P3.10
VL - 2019
SP - 794
EP - 799
AN - OPUS4-48381
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Souza Machado, A. A.
A1 - Lau, C. W.
A1 - Kloas, W.
A1 - Bergmann, J.
A1 - Bachelier, J. B.
A1 - Faltin, E.
A1 - Becker, Roland
A1 - Görlich, A. S.
A1 - Rillig, M. C.
T1 - Microplastics can change soil properties and affect plant performance
N2 - Microplastics can affect biophysical properties of the soil. However, little is known about the cascade of events in fundamental levels of terrestrial ecosystems, i.e., starting with the changes in soil abiotic properties and propagating across the various components of soil−plant interactions, including soil microbial communities and plant traits. We investigated here the effects of six different microplastics (polyester fibers, polyamide beads, and four fragment types: polyethylene, polyester terephthalate, polypropylene, and polystyrene) on a broad suite of proxies for soil health and performance of spring onion (Allium fistulosum). Significant changes were observed in plant biomass, tissue elemental composition, root traits, and soil microbial activities. These plant and soil responses to microplastic exposure were used to propose a causal model for the mechanism of the effects. Impacts were dependent on particle type, i.e., microplastics with a shape similar to other natural soil particles elicited smaller differences from control. Changes in soil structure and water dynamics may explain the observed results in which polyester fibers and polyamide beads triggered the most pronounced impacts on plant traits and function. The findings reported here imply that the pervasive microplastic contamination in soil may have consequences for plant performance and thus for agroecosystems and terrestrial biodiversity.
KW - Mikroplastik
KW - Boden
KW - Pflanzenwachstum
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484181
DO - https://doi.org/10.1021/acs.est.9b01339
SN - 0013-936X
SN - 1520-5851
VL - 53
IS - 10
SP - 6044
EP - 6052
PB - ACS
AN - OPUS4-48418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kotthoff, Lisa
A1 - Lisec, Jan
A1 - Schwerdtle, T.
A1 - Koch, Matthias
T1 - Prediction of transformation products of monensin by electrochemistry compared to microsomal assay and hydrolysis
N2 - The knowledge of transformation pathways and identification of transformation products (TPs) of veterinary drugs is important for animal health, food, and environmental matters. The active agent Monensin (MON) belongs to the ionophore antibiotics and is widely used as a veterinary drug against coccidiosis in broiler farming. However, no electrochemically (EC) generated TPs of MON have been described so far. In this study, the online coupling of EC and mass spectrometry (MS) was used for the generation of oxidative TPs. EC-conditions were optimized with respect to working electrode material, solvent, modifier, and potential polarity. Subsequent LC/HRMS (liquid chromatography/high resolution mass spectrometry) and MS/MS experiments were performed to identify the structures of derived TPs by a suspected target analysis. The obtained EC-results were compared to TPs observed in metabolism tests with microsomes and hydrolysis experiments of MON.
Five previously undescribed TPs of MON were identified in our EC/MS based study and one TP, which was already known from literature and found by a microsomal assay, could be confirmed.
Two and three further TPs were found as products in microsomal tests and following hydrolysis, respectively. We found decarboxylation, O-demethylation and acid-catalyzed ring-opening reactions to be the major mechanisms of MON transformation.
KW - Transformation products
KW - Monensin
KW - Veterinary drugs
KW - Electrochemistry
KW - Hydrolysis
KW - LC/HRMS
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485689
DO - https://doi.org/10.3390/molecules24152732
SN - 1420-3049
VL - 24
IS - 15
SP - 2732, 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-48568
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Horn, Wolfgang
A1 - Jann, Oliver
A1 - Brosig, L.
A1 - Müller, B.
A1 - Mertes, A.
A1 - de Lima Vasconcelos, S.
T1 - Emissions- und geruchsarme Bauprodukte für energieeffiziente Gebäude – Entwicklung von Anforderungen und Konzepten für den Blauen Engel aus Klimaschutzsicht
N2 - Menschen, die in der gemäßigten Klimazone leben, verbringen bis zu 90% ihres Lebens in Innenräumen. Deshalb hat das Innenraumklima eine sehr große Bedeutung für deren Wohlergehen, Gesundheit und Leistungsfähigkeit. In Deutschland wird ca. 40% der eingesetzten Primärenergie für das Heizen, Kühlen und Klimatisieren der Innenräume verwendet.
Das Forschungsvorhaben hat eine Laufzeit vom Oktober 2013 bis März 2017. Es wird in Kooperation mit der Bundesanstalt für Materialforschung und –prüfung (BAM) und der Hochschule für Technik und Wirtschaft Berlin (HTW Berlin) durchgeführt. Die HTW Berlin koordiniert das Projekt. Die Rheinisch-Westfälische Technische Hochschule Aachen (RWTH) wird teilweise über einen Auftrag in das Projekt integriert.
Ziel des Projektes ist es Baustoffe auf ihre Geruchsemissionen zu untersuchen, um Bauprodukte mit niedrigen Emissionen und Gerüchen identifizieren zu können. Den Verbraucherinnen und Verbrauchern wird somit die Möglichkeit gegeben emissions- und geruchsarme Baustoffe zu wählen.
Die Aufgabenstellung des Projektes ist nachfolgend aufgeführt:
Arbeitspaket 1: Geruchsmessung bei Produkten mit dem Blauen Engel (siehe Kapitel 4 und 5);
Arbeitspaket 2: Untersuchung von Vergleichsmaßstäben (siehe Kapitel 6);
Arbeitspaket 3: Untersuchung der Linearität der Acetonskala (siehe Kapitel 7);
Arbeitspaket 4: Erstellung einer Produktdatenbank (siehe Kapitel 8).
Die Geruchsuntersuchung ist in den Vergabekriterien für den „Blauen Engel“ für textile Bodenbeläge (RAL UZ-128) eingebunden worden. Aus den weiteren Untersuchungen sind für die Normung wichtige Erkenntnisse erarbeitet worden.
KW - VOC Emissionen
KW - Geruch
KW - Bewertung
KW - Innenraumluftqualtität
KW - Bodenbeläge
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487223
UR - https://www.umweltbundesamt.de/publikationen/emissions-geruchsarme-bauprodukte-fuer
UR - https://www.umweltbundesamt.de/sites/default/files/medien/1410/publikationen/2019-08-20-texte_92-2019_emissionsarme-bauprodukte.pdf
SN - 1862-4804
VL - 92
SP - 1
EP - 106
PB - Umweltbundesamt
CY - Dessau-Roßlau
AN - OPUS4-48722
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Wegmann, Marc
A1 - Jochum, T.
A1 - Somma, V.
A1 - Sowa, M.
A1 - Scholz, J.
A1 - Fröhlich, E.
A1 - Hoffmann, Katrin
A1 - Niehaus, J.
A1 - Roggenbuck, D.
A1 - Resch-Genger, Ute
T1 - An automatable platform for genotoxicity testing of nanomaterials based on the fluorometric γ-H2AX assay reveals no genotoxicity of properly surface-shielded cadmium-based quantum dots
N2 - The large number of nanomaterial-based applications emerging in the materials and life sciences and the foreseeable increasing use of these materials require methods that evaluate and characterize the toxic potential of these nanomaterials to keep safety risks to people and environment as low as possible. As nanomaterial toxicity is influenced by a variety of parameters like size, shape, chemical composition, and surface chemistry, high throughput screening (HTS) platforms are recommended for assessing cytotoxicity. Such platforms are not yet available for genotoxicity testing. Here, we present first results obtained for application-relevant nanomaterials using an automatable genotoxicity platform that relies on the quantification of the phosphorylated histone H2AX (γ-H2AX) for detecting DNA double strand breaks (DSBs) and the automated microscope system AKLIDES® for measuring integral fluorescence intensities at different excitation wavelengths. This platform is used to test the genotoxic potential of 30 nm-sized citrate-stabilized gold nanoparticles (Au-NPs) as well as micellar encapsulated iron oxide nanoparticles (FeOx-NPs) and different cadmium (Cd)-based semiconductor quantum dots (QDs), thereby also searching for positive and negative controls as reference materials. In addition, the influence of the QD shell composition on the genotoxic potential of these Cd-based QDs was studied, using CdSe cores as well as CdSe/CdS core/shell and CdSe/CdS/ZnS core/shell/shell QDs. Our results clearly revealed the genotoxicity of the Au-NPs and its absence in the FeOx-NPs. The genotoxicity of the Cd-QDs correlates with the shielding of their Cd-containing core, with the core/shell/shell architecture preventing genotoxicity risks. The fact that none of these nanomaterials showed cytotoxicity at the chosen particle concentrations in a conventional cell viability assay underlines the importance of genotoxicity studies to assess the hazardous potential of nanomaterials.
KW - Nanomaterial
KW - Genotoxicity testing
KW - γ-H2AX assay
KW - Quantum dot
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486318
DO - https://doi.org/10.1039/C9NR01021A
SN - 2040-3372
SN - 2040-3364
VL - 11
IS - 28
SP - 13458
EP - 13468
PB - The Royal Society of Chemistry
AN - OPUS4-48631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Lima Vasconcelos, S.
A1 - Sattler, M.
A1 - Müller, B.
A1 - Plehn, W.
A1 - Horn, Wolfgang
T1 - The Influence of textile floor coverings on the indoor air quality
N2 - Textile floor coverings are often used in offices and residential buildings. Large areas like meeting rooms, cinemas, theaters and hotels are often equipped with such coverings. They contribute to the comfort of the users as they provide high pedaling comfort and sound absorption. The weakness of these building materials is due to the odor emission that is released from the floor covering, which affects the comfort of the users. A bad air quality and the resulting dissatisfaction can lead to lower employee productivity. The research project of the Hochschule für Technik und Wirtschaft Berlin (HTW-Berlin) is promoted by the German Environment Agency (UBA). The project has the following title: Low-emission and low-odor building products for energy-efficient buildings - Development of requirements and concepts for the Blue Angel from a climate protection perspective; investigates the emission and odor behavior of textile floor coverings (Emissions- und geruchsarme Bauprodukte für energieeffiziente Gebäude - Entwicklung von Anforderungen und Konzepten für den Blauen Engel aus Klimaschutzsicht; untersucht das Emissions- und Geruchsverhalten textiler Bodenbeläge).
T2 - Clima 2019 Congress
CY - Bucharest, Romania
DA - 26.05.2019
KW - VOC Emissionen
KW - Geruch
KW - Bodenbelag
KW - AgBB Bewertung
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487341
DO - https://doi.org/10.1051/e3sconf/201911102051
SN - 2267-1242
VL - 111
SP - 02051-1
EP - 02051-6
PB - EDP Sciences
AN - OPUS4-48734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saleh, Maysoon I.
A1 - Panas, I.
A1 - Frenzel, Florian
A1 - Würth, Christian
A1 - Rühle, Bastian
A1 - Slominskii, Y.
A1 - Demchenko, A.
A1 - Resch-Genger, Ute
T1 - Sensitization of upconverting nanoparticles with a NIR-emissive cyanine dye using a micellar encapsulation approach
N2 - Photon upconversion nanomaterials have a wide range of applications, including biosensing and deep-tissue imaging. Their typically very weak and narrow absorption bands together with their size dependent luminescence efficiency can limit their application potential. This has been addressed by increasingly sophisticated core-shell particle architectures including the sensitization with organic dyes that strongly absorb in the near infrared (NIR). In this work, we present a simple water-dispersible micellar system that features energy transfer from the novel NIR excitable dye, 1859 SL with a high molar absorption coefficient and a moderate fluorescence quantum yield to oleate-capped NaYF4:20%Yb(III), 2%Er(III) upconversion nanoparticles (UCNP) upon 808 nm excitation. The micelles were formed using the surfactants Pluronic F-127 and Tween 80 to produce a hydrophilic dye-UCNP system. Successful energy transfer from the dye to the UCNP could be confirmed by emission measurements that revealed the occurrence of upconversion emission upon excitation at 808 nm and an enhancement of the green Er(III) emission compared to direct Er(III) excitation at 808 nm.
KW - Upconversion nanoparticles
KW - Sensitization
KW - NIR dyes
KW - Energy transfer
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472300
DO - https://doi.org/10.1088/2050-6120/aafe1f
SN - 2050-6120
VL - 7
IS - 1 (Special issue: Upconversion Methods, Applications and Materials)
SP - 014003-1
EP - 014003-9
PB - IOP
AN - OPUS4-47230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kröcke, N.
A1 - Grebenteuch, S.
A1 - Keil, C.
A1 - Demtröder, S.
A1 - Koch, L.
A1 - Thünemann, Andreas
A1 - Benning, R.
A1 - Haase, H.
T1 - Effect of different drying methods on nutrient quality of the yellow mealworm (Tenebrio molitor L.)
N2 - Yellow mealworm (Tenebrio molitor L.) represents a sustainable source of proteins and fatty acids for feed and food. Industrial production of mealworms necessitates optimized processing techniques, where drying as the first postharvest procedure is of utmost importance for the quality of the final product. This study examines the nutritional quality of mealworm larvae processed by rack oven drying, vacuum drying or freeze drying, respectively. Proximate composition and fatty acid profile were comparable between the dried larvae. In contrast, larvae color impressions and volatile compound profiles were very much dependent on processing procedure. High-temperature rack oven drying caused pronounced darkening with rather low content of volatiles, pointing toward the progress of Maillard reaction. On the other hand, vacuum drying or freeze drying led to enrichment of volatile Maillard reaction and lipid oxidation intermediates, whose actual sensory relevance needs to be clarified in the future. Beyond sensory and visual importance drying intermediates have to be considered with regard to their metal ion chelating ability; in particular for essential trace elements such as Zn2+. This study found comparable total zinc contents for the differently dried mealworm samples. However, dried larvae, in particular after rack oven drying, had only low zinc accessibility, which was between 20% and 40%. Therefore, bioaccessibility rather than total zinc has to be considered when their contribution to meeting the nutritional requirements for zinc in humans and animals is evaluated.
KW - Food
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476320
DO - https://doi.org/10.3390/insects10040084
SN - 2075-4450
VL - 10
IS - 4
SP - 84, 1
EP - 13
PB - MDPI
AN - OPUS4-47632
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kotthoff, Lisa
A1 - Keller, Julia
A1 - Lörchner, Dominique
A1 - Mekonnen, Tessema F.
A1 - Koch, Matthias
T1 - Transformation products of organic contaminants and residues - Overview of current simulation methods
N2 - The formation of transformation products (TPs) from contaminants and residues is becoming an increasing focus of scientific community. All organic compounds can form different TPs, thus demonstrating the complexity and interdisciplinarity of this topic. The properties of TPs could stand in relation to the unchanged substance or be more harmful and persistent. To get important information about the generated TPs, methods are needed to simulate natural and manmade transformation processes. Current tools are based on metabolism studies, photochemical methods, electrochemical methods, and Fenton's reagent. Finally, most transformation processes are based on redox reactions. This review aims to compare these methods for structurally different compounds. The groups of pesticides, pharmaceuticals, brominated flame retardants, and mycotoxins were selected as important residues/contaminants relating to their worldwide occurrence and impact to health, food, and environmental safety issues. Thus, there is an increasing need for investigation of transformation processes and identification of TPs by fast and reliable methods.
KW - Transformation product
KW - Electrochemistry
KW - Photochemistry
KW - Fenton’s reagent
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474108
DO - https://doi.org/10.3390/molecules24040753
SN - 1420-3049
VL - 24
IS - 4
SP - 753, 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-47410
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dorgerloh, Ute
A1 - Becker, Roland
A1 - Kaiser, M.
T1 - Evidence for the formation of difluoroacetic acid in chlorofluorocarbon-contaminated ground water
N2 - The concentrations of difluoroacetic acid (DFA) and trifluoroacetic acid (TFA) in rainwater and surface water from Berlin, Germany resembled those reported for similar urban areas, and the TFA/DFA ratio in rainwater of 10:1 was in accordance with the literature. In contrast, nearby ground water historically contaminated with 1,1,2-trichloro-1,2,2-trifluoroethane (R113) displayed a TFA/DFA ratio of 1:3. This observation is discussed versus the inventory of microbial Degradation products present in this ground water along with the parent R113 itself. A microbial Transformation of chlorotrifluoroethylene (R1113) to DFA so far has not been reported for environmental media, and is suggested based on well-established mammalian metabolic pathways.
KW - Fluoroacetic acid
KW - DFA
KW - TFA
KW - Rainwater
KW - Ground water
KW - Degradation of refrigerants
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475569
DO - https://doi.org/10.3390/molecules24061039
SN - 1420-3049
VL - 24
IS - 6
SP - 1039, 1
EP - 6
PB - MDPI
CY - Basel
AN - OPUS4-47556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tarantini, A.
A1 - Wegner, Karl David
A1 - Dussert, F.
A1 - Sarret, G.
A1 - Beal, D.
A1 - Mattera, L.
A1 - Lincheneau, C.
A1 - Proux, O.
A1 - Truffier-Boutry, D.
A1 - Moriscot, C.
A1 - Gallet, B.
A1 - Jouneau, P.-H.
A1 - Reiss, P.
A1 - Carriere, M.
T1 - Physicochemical alterations and toxicity of InP alloyed quantum dots aged in environmental conditions: A safer by design evaluation
N2 - Due to their unique optical properties, quantum dots (QDs) are used in a number of optoelectronic devices and are forecasted to be used in the near future for biomedical applications. The most popular QD composition consists of cadmium selenide (CdSe) or cadmium telluride (CdTe), which has been shown to pose health risks due to the release of toxic cadmium (Cd) ions. Due to similar optical properties but lower intrinsic toxicity, indium phosphide (InP) QDs have been proposed as a safer alternative. Nevertheless, investigations regarding their safety and possible toxicological effects are still in their infancy.
The fate and toxicity of seven different water-dispersible indium (In) based QDs, either pristine or after ageing in a climatic chamber, was evaluated. The core of these QDs was composed of indium, zinc and phosphorus (InZnP) or indium, zinc, phosphorus and sulfur (InZnPS). They were assessed either as core-only or as core-shell QDs, for which the core was capped with a shell of zinc, selenium and sulfur (Zn(Se,S)). Their Surface was functionalized using either penicillamine or glutathione.
In their pristine form, these QDs showed essentially no cytotoxicity. The particular case of InZnPS QD showed that core-shell QDs were less cytotoxic than core-only QDs. Moreover, surface functionalization with either penicillamine or glutathione did not appreciably influence cytotoxicity but affected QD stability. These QDs did not lead to over-accumulation of reactive oxygen species in exposed cells, or to any oxidative damage to cellular DNA. However, accelerated weathering in a climatic chamber led to QD precipitation and degradation, together with significant cytotoxic effects. Ageing led to dissociation of IneP and ZneS bonds, and to complexation of In Zn ions with carboxylate and/or phosphate moieties.
These results show that InZnP and InZnPS alloyed QDs are safer alternatives to CdSe QDs. They underline the necessity to preserve as much as possible the structural integrity of QDs, for instance by developing more robust shells, in order to ensure their safety for future applications.
KW - Indium phosphide
KW - Safe by design
KW - Toxicity
KW - EXAFS
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483070
DO - https://doi.org/10.1016/j.impact.2019.100168
VL - 14
SP - 100168-1
EP - 100168-13
PB - Elsevier
AN - OPUS4-48307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neumann, Patrick P.
A1 - Kohlhoff, Harald
A1 - Hüllmann, Dino
A1 - Krentel, Daniel
A1 - Kluge, Martin
A1 - Dzierliński, M.
A1 - Lilienthal, A. J.
A1 - Bartholmai, Matthias
T1 - Aerial-based gas tomography – from single beams to complex gas distributions
N2 - In this paper, we present and validate the concept of an autonomous aerial robot to reconstruct tomographic 2D slices of gas plumes in outdoor environments. Our platform, the so-called Unmanned Aerial Vehicle for Remote Gas Sensing (UAV-REGAS), combines a lightweight Tunable Diode Laser Absorption Spectroscopy (TDLAS) gas sensor with a 3-axis aerial stabilization gimbal for aiming at a versatile octocopter. While the TDLAS sensor provides integral gas concentration measurements, it does not measure the distance traveled by the laser diode’s beam nor the distribution of gas along the optical path. Thus, we complement the set-up with a laser rangefinder and apply principles of Computed Tomography (CT) to create a model of the spatial gas distribution from a set of integral concentration measurements. To allow for a fundamental ground truth evaluation of the applied gas tomography algorithm, we set up a unique outdoor test environment based on two 3D ultrasonic anemometers and a distributed array of 10 infrared gas transmitters. We present results showing its performance characteristics and 2D plume reconstruction capabilities under realistic conditions. The proposed system can be deployed in scenarios that cannot be addressed by currently available robots and thus constitutes a significant step forward for the field of Mobile Robot Olfaction (MRO).
KW - Aerial robot olfaction
KW - Mobile robot olfaction
KW - Gas tomography
KW - TDLAS
KW - Plume
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487843
DO - https://doi.org/10.1080/22797254.2019.1640078
SP - 1
EP - 16
PB - Taylor & Francis
CY - London
AN - OPUS4-48784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rastayesh, S.
A1 - Long, Lijia
A1 - Sørensen, J. D.
A1 - Thöns, Sebastian
T1 - Risk Assessment and Value of Action Analysis for Icing Conditions of Wind Turbines Close to Highways
N2 - The paper presents research results from the Marie Skłodowska-Curie Innovative Training Network INFRASTAR in the field of reliability approaches for decision-making for wind turbines and bridges. This paper addresses the application of Bayesian decision analysis for installation of heating systems in wind turbine blades in cases where an ice detection system is already installed in order to allow wind turbines to be placed close to highways. Generally, application of ice detection and heating systems for wind turbines is very relevant in cases where the wind turbines are planned to be placed close to urban areas and highways, where risks need to be considered due to icing events, which may lead to consequences including human fatality, functional disruptions, and/or economic losses. The risk of people being killed in a car passing on highways near a wind turbine due to blades parts or ice pieces being thrown away in cases of overicing is considered in this paper. The probability of being killed per kilometer and per year is considered for three cases: blade parts thrown away as a result of a partial or total failure of a blade, ice thrown away in two cases, i.e., of stopped wind turbines and of wind turbines in operation. Risks due to blade parts being thrown away cannot be avoided, since low strengths of material, maintenance or manufacturing errors, mechanical or electrical failures may result in failure of a blade or blade part. The blade (parts) thrown away from wind turbines in operation imply possible consequences/fatalities for people near the wind turbines, including in areas close to highways.
Similar consequences are relevant for ice being thrown away from wind turbine blades during icing situations. In this paper, we examine the question as to whether it is valuable to put a heating System on the blades in addition to ice detection systems. This is especially interesting in countries with limited space for placing wind turbines; in addition, it is considered if higher power production can be obtained due to less downtime if a heating system is installed.
KW - Risk assessment
KW - Value of action analysis
KW - Icing conditions
KW - Wind turbine
KW - Blade
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-487805
DO - https://doi.org/10.3390/en12142653
VL - 12
IS - 14
SP - 2653-1
EP - 2653-15
PB - MDPI
AN - OPUS4-48780
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stajanca, Pavol
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Distributed Fiberoptic Sensor for Simultaneous Humidity and Temperature Monitoring Based on Polyimide-Coated Optical Fibers
N2 - Along temperature, humidity is one of the principal environmental factors that plays an important role in various application areas. Presented work investigates possibility of distributed fiberoptic humidity monitoring based on humidity-induced strain measurement in polyimide (PI)-coated optical fibers. Characterization of relative humidity (RH) and temperature response of four different commercial PI- and one acrylate-coated fiber was performed using optical backscattering reflectometry (OBR). The study addresses issues of temperature-humidity cross sensitivity, fiber response stability, repeatability, and the influence of annealing. Acrylate-coated fiber exhibited rather unfavorable nonlinear RH response with strong temperature dependence, which makes it unsuitable for humidity sensing applications. On the other hand, humidity response of PI-coated fibers showed good linearity with fiber sensitivity slightly decreasing at rising temperatures. In the tested range, temperature sensitivity of the fibers remained humidity independent. Thermal annealing was shown to considerably improve and stabilize fiber RH response. Based on performed analysis, a 20 m sensor using the optimal PI-coated fibers was proposed and constructed. The sensor uses dual sensing fiber configuration for mutual decoupling and simultaneous measurement of temperature and RH variations. Using OBR, distributed dual temperature-RH monitoring with cm spatial resolution was demonstrated for the first time.
KW - Distributed humidity sensing
KW - Fiberoptic sensors
KW - Polyimide-coated optical fibers
KW - Optical frequency-domain reflectometry
KW - Dual sensing
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498871
DO - https://doi.org/10.3390/s19235279
VL - 19
IS - 23
SP - 5279
PB - MDPI
AN - OPUS4-49887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hicke, Konstantin
A1 - Eisermann, René
A1 - Chruscicki, Sebastian
T1 - Enhanced Distributed Fiber Optic Vibration Sensing and Simultaneous Temperature Gradient Sensing Using Traditional C-OTDR and Structured Fiber with Scattering Dots
N2 - We present results demonstrating several beneficial effects on distributed fiber optic vibration sensing (DVS) functionality and performance resulting from utilizing standard single mode optical fiber (SMF) with femtosecond laser-inscribed equally-spaced simple scattering dots. This modification is particularly useful when using traditional single-wavelength amplitude-based coherent optical time domain reflectometry (C-OTDR) as sensing method. Local sensitivity is increased in quasi-distributed interferometric sensing zones which are formed by the fiber segments between subsequent pairs of the scattering dots. The otherwise nonlinear transfer function is overwritten with that of an ordinary two-beam interferometer. This linearizes the phase response to monotonous temperature variations. Furthermore, sensitivity fading is mitigated and the demodulation of low-frequency signals is enabled. The modification also allows for the quantitative determination of local temperature gradients directly from the C-OTDR intensity traces. The dots’ reflectivities and thus the induced attenuation can be tuned via the inscription process parameters. Our approach is a simple, robust and cost-effective way to gain these sensing improvements without the need for more sophisticated interrogator technology or more complex fiber structuring, e.g., based on ultra-weak FBG arrays. Our claims are substantiated by experimental evidence.
KW - Fiber optic sensors
KW - Distributed vibration sensing
KW - DVS
KW - Distributed temperature gradient sensing
KW - DTGS
KW - C-OTDR
KW - Phase-sensitive
KW - OTDR
KW - Fiber structuring
KW - Fs-inscription
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499281
DO - https://doi.org/10.3390/s19194114
VL - 19
IS - 19
SP - 4114
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-49928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Vehicle-track-soil interaction and train-induced ground vibration – Theory and measurements in Germany, Switzerland and France
N2 - Three measurement campaigns of train-induced ground vibrations are evaluated for the vehicle-track-soil interaction. Ground vibrations, track vibrations and vehicle vibrations have been measured for train passages and impulse excitation and compared with theoretical results.
The soil and the track-soil system are calculated by wavenumber integrals. The influence of the vehicle is introduced by a substructure method. By comparing theory and measurement the different components of excitation force and ground vibration can be analysed, the quasi-static excitation, track-alignment errors, the out-of-roundness of wheels, the wheel and rail roughness, and moreover, scattered axle impulses and ineffective high-frequency parts of the wheelset accelerations and forces.
KW - Vehicle-track-soil interaction
KW - Train-induced ground vibration
KW - Measurement campaigns
KW - Wavenumber integrals
KW - Components of excitation
KW - Wheelset accelerations
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486702
DO - https://doi.org/10.1088/1742-6596/1264/1/012034
SN - 1742-6596
SN - 1742-6588
VL - 1264
SP - Artikel 012034-1
EP - 12
PB - IOP Publishing Ltd
AN - OPUS4-48670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Johann, Sergej
A1 - Strangfeld, Christoph
A1 - Zimmek, David
A1 - Bartholmai, Matthias
ED - Helmerich, Rosemarie
ED - Ilki, A.
ED - Motavalli, M.
T1 - Smart electronic helper for long-term monitoring of bridges and building structures
N2 - Increasing traffic volume on the one hand and ageing infrastructure on the other hand have created many new challenges for maintenance and structural health monitoring of roads and bridges. In the past, many bridges and road structures have been neglected, often resulting in traffic congestion, road closure, and increased repair costs.
This research is concerned with the development of a system to improve the challenge of maintenance and early detection of damage, particularly moisture penetration and corrosion of steel reinforced concrete components. The objective is to develop a method that will also work after 30 years and longer. Many new IoT solutions are equipped with internal energy storage elements (accumulators or batteries) which are inappropriate here, since most relevant signs of concrete degradation occur after decades, where the functioning of such elements are more than questionable. The presented technology approach uses radio-frequency identification (RFID) and enables connectivity to sensors. It offers the advantage of an passive, completely independent energy supply without any energy storage components.
Since the system should be permanently embedded in concrete, it is crucial to develop a long-term stable device which is adapted to the environmental influences of the structure, e.g., long-term resistance in very alkaline environment of pH 13. In numerous experiments, the robustness of the system was tested and evaluated. Various tests with encapsulations to protect the electronics were performed, and for long-term validation different concrete specimens were instrumented with RFID-sensor-systems. Their operating time is now around two years and investigations for signs of fatigue and damage to the encapsulation and the electronics are ongoing.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019)
CY - Potsdam, Germany
DA - 27.08.2019
KW - Long term monitoring
KW - Passive RFID
KW - SHM
KW - Sensors
KW - Smart structures
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489890
SP - 1
EP - 6
PB - German Society for Non-Destructive Testing (DGZfP e.V.)
AN - OPUS4-48989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jonietz, Florian
A1 - Krankenhagen, Rainer
A1 - Altenburg, Simon
A1 - Eisenkrein-Kreksch, H.
T1 - Standardisierung eines thermografischen Verfahrens zur Schichtdickenbestimmung von Beton-Oberflächenschutzsystemen
N2 - Polymerbeschichtungen auf Beton bieten einerseits mechanischen Schutz vor Beschädigungen und verhindern das Eindringen von Wasser, gelösten Salzen und CO2 und können andererseits der Oberfläche ein gewünschtes Aussehen geben. Daher werden sie in der Bauindustrie insbesondere bei Brücken und Parkhäusern häufig verwendet. Für die beabsichtigte Wirkung der Beschichtung ist deren Schichtdicke ein entscheidender Faktor und muss daher nach Aufbringung der Schicht und im Betrieb regelmäßig überprüft werden. Üblich sind hier zerstörende Verfahren mit nachträglich erforderlicher Ausbesserung. Im Rahmen eines Vorgängerprojektes wurde an der BAM in Kooperation mit der IBOS GmbH ein zerstörungsfreies Verfahren entwickelt, welches auf aktiver Thermografie basiert. Ein Prototyp mit Halogenlampe und Infrarot-Kamera wurde erprobt.
Das hier beschriebene Folgeprojekt hat das Ziel, dieses Verfahren zu standardisieren, damit es sich in der Industrie als zerstörungsfreies Alternativverfahren zur Schichtdickenbestimmung durchsetzt. Im ersten Schritt wird gezeigt, bei welchen Oberflächenschutzsystemen das Verfahren bereits zuverlässige Schichtdickenmessungen ermöglicht und praxistauglich ist. Anschließend werden weitere Forschungsthemen definiert und bearbeitet, die eine Anwendung für alle Oberflächenschutzsysteme ermöglichen sollen. Besondere Herausforderungen stellen etwa Sandeinstreuungen in der Polymerschicht dar. Auch muss der Frage nach der Anwendbarkeit auf Mehrschichtsysteme nachgegangen werden. Des Weiteren stellt sich die Frage nach dem Einfluss der Beschaffenheit des Betonuntergrunds auf die Anwendbarkeit des Verfahrens. Im zu erarbeitenden Normentwurf sollen diese Untersuchungen die Möglichkeiten, aber auch die Grenzen der aktiven Thermografie zur Schichtdickenmessung von Oberflächenschutzsystemen aufzeigen. Im Beitrag werden die systematischen Untersuchungen bezüglich dieser Fragestellungen dargelegt.
T2 - DACH-Jahrestagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - thermografisches Verfahren
KW - Standardisierung
KW - Schichtdickenbestimmung
KW - Beton-Oberflächenschutzsysteme
KW - Polymerbeschichtungen auf Beton
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-490093
UR - http://www.ndt.net/?id=24548
SN - 978-3-947971-02-2
VL - 171
SP - Mi.1.C.4-1
EP - Mi.1.C.4-9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-49009
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wosniok, Aleksander
A1 - Jansen, R.
A1 - Chen, L.
A1 - Toet, P.
A1 - Doppenberg, E.
A1 - De Jong, W.
A1 - Chruscicki, Sebastian
T1 - Static load monitoring of a concrete bridge using a high-precision distributed fiber optic sensor system
N2 - In the present study, the impact of static traffic loading on the slight deflection effects in the concrete structure of an existing bridge has been investigated using distributed fiber optic sensors. In the face of increasing traffic density and severe traffic loading, the results of the load tests on the Amsterdam bridge 705 make an important contribution to the understanding of its structural behavior. The concept of the static loading was based on the use of two 36-ton trucks stopped on the bridge at multiple pre-determined locations. The load applied in this way led to location-dependent small deflection effects recorded as longitudinal strain of the sensing fiber embedded at the underside of the bridge. The measurements were performed with a commercially-available solution based on Tunable Wavelength Coherent Optical Time Domain Reflectometry with the measurement accuracy in the range of 0.5 µm/m.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures
CY - Potsdam, Germany
DA - 27.08.2019
KW - Bridge monitoring
KW - Distributed fiber optic sensing
KW - Static load monitoring
KW - TW-COTDR
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-490408
SP - 1
EP - 8
AN - OPUS4-49040
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Habib, Abdel Karim
A1 - Schalau, Bernd
T1 - Pool evaporation - experimental data collection and modelling
N2 - When handling flammable or toxic liquids or liquefied gases, the occurrence of a leakage and formation of a liquid pool is a scenario to be considered for risk assessment. Several models are available for the estimation of the evaporating mass flow, but only a very reduced number of experimental data is available for Validation purposes.
In the last years, the Federal Institute for Materials Research and Testing (BAM) in Berlin, Germany, carried out pool Evaporation experiments with different substances in basins with a Diameter ranging from 0,50 m to 1 m mainly on open air test sites with a built up (inner city) and a non-built-up (flat terrain) topography, but also in an enclosed space. The resulting experimental data sets cover a range of vapor pressures from 0,1 bar to 0,94 bar.
The aim of this work is to make the füll data set publicly available and to provide a description of the experimental boundary conditions.
Based on these data, a Validation of existing pool Evaporation models has been carried out and eventually led to a new formulation of an evaporation model, which is also presented here, covering the whole ränge from low wind speeds up to high vapor pressures.
KW - Lache
KW - Verdunstung
KW - Verdampfung
KW - Dampfdruck
KW - Windgeschwindigkeit
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491826
DO - https://doi.org/10.1002/ceat.201800093
VL - 42
IS - 11
SP - 2450
EP - 2457
PB - WILEY‐VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-49182
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Herrmann, Ralf
A1 - Moortgat-Pick, A.
A1 - Marx, S.
ED - Helmerich, Rosemarie
ED - Ilki, A.
ED - Motavalli, M.
T1 - Vibration Analysis of Structures using a Drone (UAV) based Mobile Sensing Platform
N2 - The identification of the dynamic behavior of structures, like bridges and towers, is relevant to address multiple issues. In many cases the dynamic parameters should be acquired only once or at a frequency that doesn’t justify the installation of distinct vibration sensors for a long-term monitoring. To identify modal frequencies of a structure, a drone based mobile sensing platform has been implemented. This sensing platform measures the relative displacement be-tween the structure and the drone, which also shows a strong dynamic behavior under wind tur-bulences. By regarding the dynamic model of the drone and additional measurements at the dis-tance sensor the absolute movement of the structure can be estimated based on the measured relative distance. This time domain data is a suitable input for various operational modal analysis algorithms. The system has been used to identify the dynamic properties of test and real structure, like a 1.5 MW wind turbine tower.
T2 - 5th International Conference on Smart Monitoring, Assessment and Rehabilitation of Civil Structures (SMAR 2019)
CY - Potsdam, Germany
DA - 27.08.2019
KW - Modal Analysis
KW - Drone
KW - Vibration
KW - Wind Turbines
KW - Bridges
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492045
UR - http://data.smar-conferences.org/downloads/SMAR_2019_Proceedings.zip
SN - 978-3-947971-07-7
SP - We.4.C.3
EP - 8
PB - German Society for Non-Destructive Testing (DGZfP e.V.)
AN - OPUS4-49204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sarma, Dominik
A1 - Carl, Peter
A1 - Climent Terol, Estela
A1 - Schneider, Rudolf
A1 - Rurack, Knut
T1 - Multifunctional polystyrene core/silica shell microparticles with antifouling properties for bead-based multiplexed and quantitative analysis
N2 - Commercial bead-based assays are commonly built upon polystyrene particles. The polymeric carrier can be encoded with organic dyes and has ideal material properties for cytometric applications such as low density and high refractive index. However, functional groups are conventionally integrated during polymerization and subsequent modification is limited to the reactivity of those groups. Additionally, polystyrene as the core material leads to many hydrophobic areas still being present on the beads’ surfaces even after functionalization, Rendering the particles prone to nonspecific adsorption during an application. The latter calls for several washing steps and the use of additives in (bio)analytical assays. In this contribution, we show how these limitations can be overcome by using monodisperse polystyrene (PS) core/silica (SiO2) shell particles (SiO2@PS). Two different hydrophobic BODIPY (boron−dipyrromethene) dyes were encapsulated inside a poly(vinylpyrrolidone) (PVP) -stabilized polystyrene core in different concentrations to create 5-plex arrays in two separate detection channels of a cytometer. A subsequent modification of the silica shell with an equimolar APTES/PEGS (aminopropyltriethoxysilane/polyethylene glycol silane) blend added multifunctional properties to the hybrid core/Shell microparticles in a single step: APTES provides amino groups for the attachment of a caffeine derivative (as a hapten) to create antigen-coupled microspheres; the PEG moiety effectively suppresses nonspecific binding of antibodies, endowing the surface with antifouling properties. The particles were applied in a competitive fluorescence immunoassay in suspension, and a highly selective wash-free assay for the detection of caffeine in beverages was developed as a proof of concept.
KW - Core−shell particles
KW - Bead-based assay
KW - Multiplex
KW - Antifouling surface
KW - Mixed surface
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472931
UR - https://pubs.acs.org/doi/10.1021/acsami.8b10306
DO - https://doi.org/10.1021/acsami.8b10306
SN - 1944-8244
VL - 11
IS - 1
SP - 1321
EP - 1334
PB - American Chemical Society
CY - Online Library
AN - OPUS4-47293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kalbe, Ute
A1 - Lehnik-Habrink, Petra
A1 - Bandow, Nicole
A1 - Sauer, Andreas
T1 - Validation of European horizontal methods for the analysis of PAH, PCB and dioxins in sludge, treated biowaste and soil
N2 - Draft standards for the determination of organic pollutants in the solid matter of environmental matrices such as sludge, treated biowaste and soil have been basically developed in the framework of the European standardization project HORIZONTAL. A research project financed by the German Federal Environment Agency was initiated to finalize some of these CEN standard drafts, since fully validated standard procedures are crucial for the evaluation of their reliability in the context of implementation in legislation on environmental health.
Approach: Appropriate test materials (< 2mm particle size) were prepared and homogenized from contaminated soils, sludge and treated biowaste containing polycyclic aromatic hydrocarbons (PAH), polychlorinated biphenyls (PCB), dioxins, furans and dioxin-like-PCB and served, along with reference solutions, as the basis for international interlaboratory comparisons. Performance data of three analytical standard procedures were obtained by the statistical evaluation of results received from 11 to 29 participants per test material.
Results: The overall variation coefficients of reproducibility (between-lab standard deviations) for the sum parameters were roughly between 10 and 35 %. The variation coefficients of repeatability (within-lab standard deviations) range between 3 % and 8 % and show no trend considering the substance groups or matrices.
The highest coefficients of reproducibility were found for the analysis of PAHs, which were between 26 and 35 %, depending on the matrix, whereas 7-17 % reproducibility was observed for toxicity equivalents (TEQ) comprising dioxins, furans and dl-PCB.
Conclusions: Overall, the results confirm that the procedures described in the Technical Specifications are fit for purpose for all three matrices and that the feasibility of the HORIZONTAL approach, to cover several matrices with one standard per analyte, was thereby proven.
KW - Standardization
KW - Analytical methods
KW - Organic contaminants
KW - Validation trial
KW - Interlaboratory comparison
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479914
DO - https://doi.org/10.1186/s12302-019-0211-3
SN - 2190-4715
VL - 31
SP - 29, 1
EP - 10
PB - Springer
CY - Berlin, Heidelberg
AN - OPUS4-47991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kern, Simon
A1 - Wander, Lukas
A1 - Meyer, Klas
A1 - Guhl, Svetlana
A1 - Gottu Mukkula, A. R.
A1 - Holtkamp, M.
A1 - Salge, M.
A1 - Fleischer, C.
A1 - Weber, N.
A1 - Engell, S.
A1 - Paul, Andrea
A1 - Pereira Remelhe, M.
A1 - Maiwald, Michael
T1 - Flexible automation with compact NMR spectroscopy for continuous production of pharmaceuticals
N2 - Modular plants using intensified continuous processes represent an appealing concept for the production of pharmaceuticals. It can improve quality, safety, sustainability, and profitability compared to batch processes; besides, it enables plug-and-produce reconfiguration for fast product changes. To facilitate this flexibility by real-time quality control, we developed a solution that can be adapted quickly to new processes and is based on a compact nuclear magnetic resonance (NMR) spectrometer. The NMR sensor is a benchtop device enhanced to the requirements of automated chemical production including robust evaluation of sensor data. Beyond monitoring the product quality, online NMR data was used in a new iterative optimization approach to maximize the plant profit and served as a reliable reference for the calibration of a near-infrared (NIR) spectrometer. The overall approach
was demonstrated on a commercial-scale pilot plant using a metal-organic reaction with pharmaceutical relevance.
KW - NMR Spectroscopy
KW - NIR Spectroscopy
KW - Real-time process monitoring
KW - Real-time quality control
KW - Continuous processes
KW - CONSENS
KW - Data Fusion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-480623
DO - https://doi.org/10.1007/s00216-019-01752-y
SN - 1618-2642
SN - 1618-2650
VL - 411
IS - 14
SP - 3037
EP - 3046
PB - Springer Nature
CY - Heidelberg
AN - OPUS4-48062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gotor, Raúl
A1 - Bell, Jérémy
A1 - Rurack, Knut
T1 - Tailored fluorescent solvatochromic test strips for quantitative on-site detection of gasoline fuel adulteration
N2 - Gasoline adulteration is a frequent problem world-wide, because of the chance of quick, maximized profits. However, addition of cheaper ethanol or hydrocarbons like kerosene does not only result in economic damage but also poses problems for vehicles and the environment. To enable law enforcement forces, customers or enterprises to uncover such a fraudulent activity directly upon suspicion and without the need to organize for sampling and laboratory analysis, we developed a simple strip-based chemical test. Key to the favorable performance was the dedicated materials tailoring, which led to test strips that consisted of a cellulose support coated with silica, passivated with hexamethyldisilazane and functionalized covalently with a molecular probe. The probe fluoresces brightly across a broad solvent polarity range, enabling reliable quantitative measurements and data analysis with a conventional smartphone. The assays showed high reproducibility and accuracy, allowing not only for the detection of gasoline adulteration but also for the on-site monitoring of the quality of commercial E10 gasoline.
KW - Gasoline
KW - Adulteration
KW - Test strips
KW - Benzin
KW - Teststreifen
KW - Fluorescence
KW - Cellulose
KW - Zellulose
KW - Fluoreszenz
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479231
UR - https://pubs.rsc.org/en/content/articlelanding/2019/tc/c8tc04818e
DO - https://doi.org/10.1039/C8TC04818E
SN - 2050-7526
VL - 7
IS - 8
SP - 2250
EP - 2256
PB - Royal Society of Chemistry
CY - London, UK
AN - OPUS4-47923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baer, Wolfram
T1 - Chunky graphite in ferritic spheroidal graphite cast iron: Formation, prevention, characterization, impact on properties – An overview
N2 - Ferritic spheroidal graphite cast iron (SGI) materials have a remarkable technical poten-tial and economic impact in modern industry. These features are closely related to the question of how the cast materials can be produced without structural defects and graphite degenerations such as for example chunky graphite. Although the chunky graphite degeneration superficially seems to be well known, its metallurgical background is still controversially discussed, appropriate field-tested non-destructive tools for its quantification in castings are lacking and the knowledge on its impact on material properties is fairly limited. Addressing this status, the article is providing a current overview on the subject. Existing theories on formation and growth mechanisms of chunky graphite are briefly reviewed. Furthermore, from a metallurgical point of view, causes for the appearance of chunky graphite as well as preventive measures are concisely summarized. Particular attention is paid to the morphology of chunky graphite and how it can be characterized by destructive and non-destructive techniques. Special emphasis was laid on providing a comprehensive overview on the impact of chunky graphite on strength, ductility, fatigue limit, fatigue crack growth rate as well as fracture tough-ness of ferritic SGI materials based on experimental data. Moreover, conclusions for the assessment of castings affected by chunky graphite are drawn.
KW - Characterization
KW - Ferritic spheroidal graphite cast iron
KW - Chunky graphite
KW - Properties
KW - Formation
KW - Prevention
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499972
DO - https://doi.org/10.1007/s40962-019-00363-8
SN - 1939-5981
SN - 2163-3193
VL - 14
IS - 2
SP - 454
EP - 488
PB - Springer Verlag
AN - OPUS4-49997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezera, M.
A1 - Bonse, Jörn
A1 - Römer, G.R.B.E.
T1 - Influence of Bulk Temperature on Laser-Induced Periodic Surface Structures on Polycarbonate
N2 - In this paper, the influence of the bulk temperature (BT) of Polycarbonate (PC) on the occurrence and growth of Laser-induced Periodic Surface Structures (LIPSS) is studied. Ultrashort UV laser pulses with various laser peak fluence levels F_0 and various numbers of overscans (N_OS) were applied on the surface of pre-heated Polycarbonate at different bulk temperatures. Increased BT leads to a stronger absorption of laser energy by the Polycarbonate. For N_OS < 1000 High Spatial Frequency LIPSS (HSFL), Low Spatial Frequency LIPSS perpendicular (LSFL-I) and parallel (LSFL-II) to the laser polarization were only observed on the rim of the ablated tracks on the surface but not in the center of the tracks. For N_OS ≥ 1000 , it was found that when pre-heating the polymer to a BT close its glass transition temperature (T_g), the laser fluence to achieve similar LIPSS as when processed at room temperature decreases by a factor of two. LSFL types I and II were obtained on PC at a BT close to T_g and their periods and amplitudes were similar to typical values found in the literature. To the best of the author’s knowledge, it is the first time both LSFL types developed simultaneously and consistently on the same sample under equal laser processing parameters. The evolution of LIPSS from HSFL, over LSFL-II to LSFL I, is described, depending on laser peak fluence levels, number of pulses processing the spot and bulk temperature.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Polycarbonate
KW - Bulk temperature
KW - Ultrashort laser pulses
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498242
UR - https://www.mdpi.com/2073-4360/11/12/1947
DO - https://doi.org/https://doi.org/10.3390/polym11121947
SN - 2073-4360
VL - 11
IS - 12
SP - 1947
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-49824
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oesch, Tyler
A1 - Weise, Frank
A1 - Meinel, Dietmar
A1 - Gollwitzer, Christian
T1 - Quantitative in-situ analysis of water transport in concrete completed using X-ray computed tomography
N2 - This paper describes a novel methodology for quantitative in-situ moisture measurement without tracking agents using X-ray computed tomography (XCT). The high levels of grey-scale precision required for the measurement of moisture without tracking agents resulted in the need for an additional image calibration procedure to correct for water-related X-ray scattering and for equipment-variability related artefacts arising during in-situ testing. This calibration procedure was developed on the basis of existing principles of XCT image cor-rection. Resulting images of moisture distribution exhibit a high level of agreement with expected material behaviour. This research demonstrated that XCT can be successfully used to measure both moisture-front movement over time and changes in 3D moisture distribution within samples. This approach to moisture measurement lays the groundwork for the planned future investigation of the interaction between cracking induced by varying chemical and mechanical processes and water transport in concrete.
KW - X-ray computed tomography (XCT)
KW - In-situ testing
KW - Water transport
KW - Quantitative moisture measurement
KW - Concrete
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474395
DO - https://doi.org/10.1007/s11242-018-1197-9
SN - 1573-1634
VL - 127
IS - 2
SP - 371
EP - 389
PB - Springer Netherlands
AN - OPUS4-47439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bartelmeß, Jürgen
A1 - Valderrey, Virginia
A1 - Rurack, Knut
T1 - Development of a “Turn-on” Fluorescent Probe-Based Sensing System for Hydrogen Sulfide in Liquid and Gas Phase
N2 - A “turn-on” fluorescence sensing system based on a BODIPY-cobaloxime complex for the detection of H2S in liquid and gas phase was developed. To that aim, two cobaloxime complexes bearing an axial pyridyl-BODIPY ligand were initially evaluated as sensitive fluorescent HS− indicators in aqueous solution. The sensing mechanism involves the selective substitution of the BODIPY ligand by the HS− anion at the cobalt center, which is accompanied by a strong fluorescence enhancement. The selection of a complex with an ideal stability and reactivity profile toward HS− relied on the optimal interaction between the cobalt metal-center and two different pyridyl BODIPY ligands. Loading the best performing BODIPY-cobaloxime complex onto a polymeric hydrogel membrane allowed us to study the selectivity of the probe for HS− against different anions and cysteine. Successful detection of H2S by the fluorescent “light-up” membrane was not only accomplished for surface water but could also be demonstrated for relevant H2S concentrations in gas phase.
KW - Sulfide sensing
KW - Fluorescence
KW - BODIPYs
KW - Cobaloxime complex
KW - Gas sensing
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492186
DO - https://doi.org/10.3389/fchem.2019.00641
SN - 2296-2646
VL - 7
SP - Art. Nr. 641
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-49218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Borzekowski, Antje
A1 - Anggriawan, R.
A1 - Auliyati, M.
A1 - Kunte, Hans-Jörg
A1 - Koch, Matthias
A1 - Rohn, S.
A1 - Karlovsky, P.
A1 - Maul, Ronald
T1 - Formation of Zearalenone Metabolites in Tempeh Fermentation
N2 - Tempeh is a common food in Indonesia, produced by fungal fermentation of soybeans using Rhizopus sp., as well as Aspergillus oryzae, for inoculation. Analogously, for economic reasons, mixtures of maize and soybeans are used for the production of so-called tempeh-like products. For maize, a contamination with the mycoestrogen zearalenone (ZEN) has been frequently reported. ZEN is a mycotoxin which is known to be metabolized by Rhizopus and Aspergillus species. Consequently, this study focused on the ZEN transformation during tempeh fermentation. Five fungal strains of the genera Rhizopus and Aspergillus, isolated from fresh Indonesian tempeh and authentic Indonesian inocula, were utilized for tempeh manufacturing from a maize/soybean mixture (30:70) at laboratory-scale. Furthermore, comparable tempeh-like products obtained from Indonesian markets were analyzed. Results from the HPLC-MS/MS analyses show that ZEN is intensely transformed into its metabolites alpha-zearalenol (alpha-ZEL), ZEN-14-sulfate, alpha-ZEL-sulfate, ZEN-14-glucoside, and ZEN-16-glucoside in tempeh production. alpha-ZEL, being significantly more toxic than ZEN, was the main metabolite in most of the Rhizopus incubations, while in Aspergillus oryzae fermentations ZEN-14-sulfate was predominantly formed. Additionally, two of the 14 authentic samples were contaminated with ZEN, alpha-ZEL and ZEN-14-sulfate, and in two further samples, ZEN and alpha-ZEL, were determined. Consequently, tempeh fermentation of ZEN-contaminated maize/soybean mixture may lead to toxification of the food item by formation of the reductive ZEN metabolite, alpha-ZEL, under model as well as authentic conditions.
KW - Modified mycotoxins
KW - Zearalenone sulfate
KW - a-zearalenol
KW - Food fermentation
KW - Rhizopus and Aspergillus oryzae
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491126
DO - https://doi.org/10.3390/molecules24152697
VL - 24
IS - 15
SP - 2697
PB - MDPI
AN - OPUS4-49112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rahrig, M.
A1 - Torge, Manfred
T1 - 3D inspection of the restoration and conservation of stained glass windows using high resolution structured light scanning
N2 - The initial focus of this research was on the development of a general workflow for the documentation and monitoring of historical stained glass windows using structured light scanning. Therefore windows from different churches, time periods and with different corrosion and damage phenomena were scanned before and after conservation measures. To evaluate the execution of the restoration measures the data was compared using 3D inspection software to examine the differences in geometry between the two scans. Various problems had to be solved, for example, how to deal with heavily reflective surfaces and the extreme contrast between light and dark surfaces, as seen in the borders between ‘Schwarzlot’ painting and plain glass. The application of materials for matting the surfaces, such as Cyclododecane spray, was impossible due to the high accuracy of the surface measurement required for 3D inspection. Regarding the contrast differences of the surfaces, the creation of exposure fusions and the use of polarization filters to reduce reflections were tested. In addition to the general problems encountered when recording translucent surfaces, the historical glasses caused additional problems in calculating surface comparisons. For example, the windows have to be moved and turned around several times, both during the conservation process and while scanning, causing deformations of the geometry due to the flexible lead rods allowing a certain degree of movement.
T2 - 27th CIPA International Symposium “Documenting the past for a better future”
CY - Ávila, Spain
DA - 01.09.2019
KW - Stained glass
KW - Restoration and conservation
KW - Structured light scanning
KW - 3D inspection
KW - Glass scanning
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491286
DO - https://doi.org/10.5194/isprs-archives-XLII-2-W15-965-2019
VL - XLII-2/W15
SP - 965
EP - 972
PB - International Society of Photogrammetry and Remote Sensing (ISPRS)
CY - Hannover
AN - OPUS4-49128
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Q.
A1 - Zheng, M.
A1 - Huang, Y.
A1 - Kunte, Hans-Jörg
A1 - Wang, X.
A1 - Liu, Y.
A1 - Zheng, C.
T1 - Long term corrosion estimation of carbon steel, titanium and its alloy in backfill material of compacted bentonite for nuclear waste repository
N2 - The container of high-level radioactive waste (HLRW) being in deep geological disposal, the backfill material is needed to serve as the second defense for HLRW and the highly compacted bentonite is generally selected. As the time goes, the underground water will infiltrate the backfill, causing the corrosion of materials for the building of containers in the formed electrolyte. Carbon steel, titanium and its alloy are the potential candidate materials for the fabrication of HLRW containers.
The current investigation aims at assessing the safety of HLRW container in deep geological disposal for hundreds of thousands of years and facilitating the material selection for future Container fabrication by estimating their corrosion behavior in compacted bentonite with a series of moisture content at different temperatures through electrochemical methods including open circuit potential (OCP), electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization curve (PC) measurements. The corrosion rates were estimated for a carbon steel, a pure titanium and a titanium alloy in compacted Gaomiaozi Bentonite infiltrated with simulated underground water in Beishan area of China over an expected disposal period up to 106 years respectively, showing that titanium and its alloy are more reliable materials for building HLRW containers than carbon steel.
KW - Issues
KW - Disposal
KW - Performance
KW - Moisture
KW - Lifetime
KW - Water
KW - Model
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492413
DO - https://doi.org/10.1038/s41598-019-39751-9
SN - 2045-2322
VL - 9
SP - 3195
PB - Nature Publishing Group
AN - OPUS4-49241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Akbar, S.
A1 - Hasanain, S.K.
A1 - Ivashenko, O.
A1 - Dutka, M.V.
A1 - Akhtar, N.
A1 - De Hosson, J.Th.M.
A1 - Ali, Naveed
A1 - Rudolf, P.
T1 - Defect ferromagnetism in SnO2:Zn2+ hierarchical nanostructures: correlation between structural, electronic and magnetic properties
N2 - We report on the ferromagnetism of Sn1-xZnxO2 (x < 0.1) hierarchical nanostructures with various morphologies synthesized by a solvothermal route. A room temperature ferromagnetic and paramagnetic response was observed for all compositions, with a maximum in ferromagnetism for x = 0.04. The ferromagnetic behaviour was found to correlate with the presence of zinc on substitutional Sn sites and with a low oxygen vacancy concentration in the samples. The morphology of the nanostructures varied with zinc concentration. The strongest ferromagnetic response was observed in nanostructures with well-formed shapes, having nanoneedles on their surfaces. These nanoneedles consist of (110) and (101) planes, which are understood to be important in stabilizing the ferromagnetic defects. At higher zinc concentration the nanostructures become eroded and agglomerated, a phenomenon accompanied with a strong decrease in their ferromagnetic response. The observed trends are explained in the light of recent computational studies that discuss the relative stability of ferromagnetic defects on various surfaces and the role of oxygen vacancies in degrading ferromagnetism via an increase in free electron concentration.
KW - Ferromagnetism
KW - Nanostructures
KW - Magnetic properties
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473014
DO - https://doi.org/10.1039/c9ra00455f
SN - 2046-2069
VL - 9
IS - 7
SP - 4082
EP - 4091
PB - Royal Society of Chemistry
AN - OPUS4-47301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Cong
A1 - Bousnina, M.
A1 - Giovannelli, F.
A1 - Delorme, F.
T1 - Influence of Bi on the thermoelectric properties of SrTiO3-δ
N2 - The thermoelectric properties of Sr1-xBixTiO3-δ (0 ≤ x ≤ 0.07) have been investigated. Dense ceramics of Sr1-xBixTiO3-δ and Sr0.95TiO3-δ have been prepared by solid-state reaction and conventional sintering in air followed by annealing in a reducing atmosphere. XRD and SEM analyses show that the rutile TiO2 in Sr0.95TiO3 formed after sintering becomes Magnéli phase of TinO2n-1 after annealing. Moreover, Bi resolves from Sr1-xBixTiO3 after annealing, resulting in the formation of Sr1-xBixTiO3-δ/Bi/TinO2n-1 composites. With increasing Bi content in Sr1-xBixTiO3-δ, the electrical conductivity increases while the absolute values of the Seebeck coefficient decrease as a result of increasing carrier concentration. The thermal conductivity of SrTiO3-δ is reduced by doping Bi up to x = 0.07. Highest ZT ~ 0.13 is obtained in Sr0.93Bi0.07TiO3-δ at 1000 K.
KW - Thermoelectrics
KW - SrTiO3
KW - Composite
KW - Magnéli phase
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472920
DO - https://doi.org/10.1016/j.jmat.2018.12.004
SN - 2352-8478
VL - 5
IS - 1
SP - 88
EP - 93
PB - Elsevier
AN - OPUS4-47292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weltschev, Margit
T1 - Compatibility of sealing materials with biofuels and biodiesel heating oil blends at different temperatures
N2 - Biofuels including ethanol and biodiesel (fatty acid methyl ester, FAME) represent an important renewable fuel alternative to petroleum-derived transport fuels. Increasing biofuels use would bring some benefits, such as a reduction in oil demands and greenhouse gas emissions, and an improvement in air quality. Materials compatibility is a major concern whenever the fuel composition is changed in a fuel system.
The objective of this research was to determine the resistance of frequently used sealing materials such as CR (chloroprene rubber), CSM (chlorosulfonated polyethylene), EPDM (ethylene-propylene-diene rubber), FKM (fluorocarbon rubber), FVMQ (methyl-fluorosilicone rubber), IIR (butyl rubber), NBR (acrylonitrile-butadiene rubber), PA (polyamides), PUR (polyester urethane rubber) and VMQ (methyl-vinyl-silicone rubber), in heating oil with admixtures of biogenic sources such as E10 (fuel with max. 10 % ethanol), E85 (fuel with 85 % ethanol), non-aged and aged biodiesel, diesel fuel with 5 % biodiesel, non-aged and aged B10 (heating oil with 10 % biodiesel) at 20 °C, 40 °C and 70 °C. Mass, tensile strength and breaking elongation of the test specimens were determined before and after the exposure for 84 days in the fuels. The visual examination of some elastomer test specimens clearly showed the great volume increase until break or partial dissolution. Shore hardness A and D (for PA) were determined before and after exposure of the test specimens in the biofuels for 42 days.
There is not determined a threshold for the reduction in tensile properties and Shore hardness in the international standards. Therefore, a threshold of 15 % was set for the evaluation of the compatibility. The sealing materials CR, CSM, EPDM, IIR and NBR were generally not resistant to biodiesel and B10. In summary, it can be therefore stated that the chemical resistance of the fluoropolymers FKM and FVMQ in fuels and biofuels is the best one.
KW - Compatibility evaluation
KW - Polymers
KW - FAME
KW - Heating oil with 10 % FAME
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479722
DO - https://doi.org/10.15344/2456-351X/2019/165
SN - 2456-351X
VL - 4
IS - 165
SP - 4
EP - 9
PB - Graphyonline Publications Pvt. Ltd.
CY - Bangalore, Karnataka, Indien
AN - OPUS4-47972
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beckmann, Jörg
ED - Spranger, Holger
T1 - Synthetische Aperturfokussierung für die Terahertzspektroskopie
N2 - Die zeitaufgelöste THz-Spektroskopie (THz-TDS) operiert mit elektromagnetischen Impulsen, die ein Amplitudenspektrum im unteren THz-Bereich aufweisen. Die THz-TDS ist in der Lage, dielektrische Volumina zerstörungs- und kontaktfreie zu durchstrahlen. Um eine 3D-THz Bildung zu ermöglichen, wurde für die THz-TDS ein rechnergestütztes Mess- und Rekonstruktionsverfahren (THz-TDSAFT) entwickelt, mit dem es gelingt, unter Verwendung der im Zeitbereich registrierten THz-TDS-Daten das Volumeninnere in Form eines dreidimensionalen Tomogramms zu rekonstruieren. Die THz-TD-SAFT basiert auf die für die Ultraschalltechnik entwickelte Synthetische Apertur Fokussierung (SAFT) bzw. des heuristisch begründeten Algorithmus des Synthetischen Apertur Radars (SAR). Anhand von Beispielen wird die Möglichkeiten der THz-TD-SAFT demonstriert und nachgewiesen, dass mit dem Rekonstruktionsansatz die künstlich eingebauten Fehlstellen bezüglich der Position und Größe geometrisch richtig im Tomogramm abgebildet werden können.
T2 - 4. Fachseminar des FA MTHz, Mikrowellen- und Terahertz-Prüftechnik in der Praxis
CY - Fürth, Germany
DA - 02.04.2019
KW - THz-TDS
KW - Tomographie,
KW - Zerstörungsfreie Prüfung
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-490481
UR - https://www.ndt.net/search/docs.php3?MainSource=262
SP - 1
EP - 8
PB - DGZfP
CY - Berlin
AN - OPUS4-49048
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Metz, Christian
A1 - Franz, Philipp
A1 - Fischer, C.
A1 - Wachtendorf, Volker
A1 - Maierhofer, Christiane
T1 - Zerstörungsfreie Charakterisierung der Alterung additiv gefertigter Kunststoffbauteile
N2 - Das vorgestellte Projekt beschäftigt sich mit den optischen, thermophysikalischen und mechanischen Materialeigenschaften von additiv gefertigten Kunststoffteilen und deren Alterung. Dazu wurden mittels Fused Layer Modeling (FLM) Probekörper aus ABS hergestellt, die anschließend für drei Monate einer künstlichen Bewitterung unterzogen wurden. Die dabei erzeugte definierte Alterung wurde nach drei Zeitabschnitten jeweils mit zerstörungsfreien Methoden charakterisiert. Dabei wurde neben den spektroskopischen Standardmethoden auch die aktive Thermografie eingesetzt. Die Ergebnisse zeigen, dass sich mittels der Thermografie sowohl chemische Veränderungen als auch mechanische Schädigungen (Fehlstellen) darstellen lassen. Die Bewitterung beeinflusst die Teiltransparenz der Proben zumindest im sichtbaren Spektralbereich, was bei der Charakterisierung der Fehlstellen, die mittels optisch angeregter aktiver Thermografie detektiert wurden, berücksichtigt werden muss.
T2 - DGZfP-Jahrestagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - 3D Druck
KW - Additive Fertigung
KW - Thermografie
KW - Polymere
KW - Künstliche Bewitterung
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-491561
UR - https://jt2019.dgzfp.de/Portals/jt2019/bb/Di.3.B.1.pdf
SN - 978-3-947971-02-2
VL - 171
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-49156
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Melzer, Michael
A1 - Makarov, D.
A1 - Schmidt, O. G.
T1 - A review on stretchable magnetic field sensorics
N2 - The current establishment of stretchable electronics to form a seamless link between soft or even living materials and the digital world is at the forefront of multidisciplinary research efforts, bridging physics, engineering and materials science. Magnetic functionalities can provide a sense of displacement, orientation or proximity to this novel formulation of electronics. This work reviews the recent development of stretchable magnetic field sensorics relying on the combination of metallic thin films revealing a giant magnetoresistance effect with elastomeric materials. Stretchability of the magnetic nanomembranes is achieved by specific morphologic features (e.g. wrinkles or microcracks), which accommodate the applied tensile deformation while maintaining the electrical and magnetic integrity of the sensor device. The entire development, from the demonstration of the world’s first elastically stretchable magnetic sensor to the realization of a technology platform for robust, ready-to-use elastic magnetosensorics is described. Soft giant magnetoresistive elements exhibiting the same sensing performance as on conventional rigid supports, but with fully strain invariant properties up to 270% stretching have been demonstrated. With their unique mechanical properties, these sensor elements readily conform to ubiquitous objects of arbitrary shapes including the human skin. Stretchable magnetoelectronic sensors can equip soft and epidermal electronic systems with navigation, orientation, motion tracking and touchless control capabilities. A variety of novel technologies, like electronic skins, smart textiles, soft robotics and actuators, active medical implants and soft consumer electronics will benefit from these new magnetic functionalities.
KW - Stretchable electronics
KW - Giant magnetoresistance
KW - Magnetic sensors
KW - Magnetic thin films
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502049
DO - https://doi.org/10.1088/1361-6463/ab52cf
SN - 0022-3727 (Druck)
SN - 1361-6463 (Web)
VL - 53
IS - 8
SP - Paper 083002, 34
PB - IOP Publishing
AN - OPUS4-50204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Palantöken, Sinam
A1 - Bethke, K.
A1 - Zivanovic, V.
A1 - Kneipp, Janina
A1 - Rademann, Klaus
A1 - Kalinka, Gerhard
T1 - Cellulose hydrogels physically crosslinked by glycine: Synthesis, characterization, thermal and mechanical properties
N2 - Biopolymers are very efficient for significant applications ranging from tissue engineering, biological devices to water purification. There is a tremendous potential value of cellulose because of ist being the most abundant biopolymer on earth, swellability, and functional groups to be modified. A novel, highly efficient route for the fabrication of mechanically stable and natural hydrogels is described in which cellulose and glycine are dissolved in an alkaline solution of NaOH and neutralized in an acidic solution. The dissolving temperature and the glycine amount are essential parameters for the self-assembly of cellulose chains and for Tuning the morphology and the aggregate structures of the resulting hydrogels. Glycine plays the role of a physical crosslinker based on the Information obtained from FTIR and Raman spectra. Among the prepared set of hydrogels, CL5Gly30 hydrogels have the highest capacity to absorb water. The prepared CL5Gly30 gels can absorb up to seven times their dry weight due to its porous 3-D network structure. CL5Gly10 hydrogel exhibits 80% deformation under 21 N force executed. The method developed in this article can contribute to the application of heavy metal adsorption in aqueous solutions for water purification and waste management.
KW - Biopolymer
KW - Cellulose
KW - Hydrogel
KW - Natural
KW - Synthesis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486845
DO - https://doi.org/10.1002/APP.48380
SN - 1097-4628
SN - 0021-8995
VL - 136
SP - 48380, 1
EP - 11
PB - Wiley
CY - USA
AN - OPUS4-48684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bramke, K.
A1 - Müller, U.
A1 - McMahon, Dino Peter
A1 - Rolff, J.
T1 - Exposure of Larvae of the Solitary Bee Osmia bicornis to the Honey Bee Pathogen Nosema ceranae Aects Life History
N2 - Wild bees are important pollinators of wild plants and agricultural crops and they are threatened by several environmental stressors including emerging pathogens. Honey bees have been suggested as a potential source of pathogen spillover. One prevalent pathogen that has recently emerged as a honey bee disease is the microsporidian Nosema ceranae. While the impacts of N. ceranae in honey bees are well documented, virtually nothing is known about its effects in solitary wild bees.
The solitary mason bee Osmia bicornis is a common pollinator in orchards and amenable to Commercial management. Here, we experimentally exposed larvae of O. bicornis to food contaminated with N. ceranae and document spore presence during larval development. We measured mortality, growth parameters, and timing of pupation in a semi-field experiment. Hatched individuals were assessed for physiological state including fat body mass, wing muscle mass, and body size. We recorded higher mortality in the viable-spore-exposed group but could only detect a low number of Spores among the individuals of this treatment. Viable-spore-treated individuals with higher head capsule width had a delayed pupation start. No impact on the physiological status could be detected in hatched imagines. Although we did not find overt evidence of O. bicornis infection, our findings indicate that exposure of larvae to viable N. ceranae spores could affect bee development.
KW - Bee diseases
KW - Wild bees
KW - Nosema ceranae
KW - Osmia bicornis
KW - Pathogen transmission
KW - Solitary bees
KW - Bee health
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496497
DO - https://doi.org/10.3390/insects10110380
VL - 10
IS - 11
SP - 380
PB - MDPI
AN - OPUS4-49649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gili, A.
A1 - Bischoff, B.
A1 - Simon, U.
A1 - Schmidt, Franziska
A1 - Kober, D.
A1 - Görke, O.
A1 - Bekheet, M.
A1 - Gurlo, A.
T1 - Ceria-based dual-phase membranes for high-temperature Carbon dioxide separation: Effect of iron doping and pore generation with MgO template
N2 - Dual-phase membranes for high-temperature carbon dioxide Separation have emerged as promising technology to mitigate anthropogenic greenhouse gases emissions, especially as a pre- and post-combustion separation technique in coal burning power plants. To implement These membranes industrially, the carbon dioxide permeability must be improved. In this study, Ce_(0.8) Sm_(0.2) O_(2-d) (SDC) and Ce_(0.8)Sm_(0.19)Fe_(0.01)O_(2-d) (FSDC) ceramic powders were used to form the skeleton in dual-Phase membranes. The use of MgO as an environmentally friendly pore generator allows control over the membrane porosity and microstructure in order to compare the effect of the membrane’s ceramic phase. The ceramic powders and the resulting membranes were characterized using ICP-OES, HSM, gravimetric analysis, SEM/EDX, and XRD, and the carbon dioxide flux density was quantified using a high-temperature membrane permeation setup. The carbon dioxide permeability slightly increases with the addition of iron in the FSDC membranes compared to the SDC membranes mainly due to the reported scavenging effect of iron with the siliceous impurities, with an additional potential contribution of an increased crystallite size due to viscous flow sintering. The increased permeability of the FSDC system and the proper microstructure control by MgO can be further extended to optimize carbon dioxide permeability in this membrane system.
KW - Samarium doped ceria
KW - SDC
KW - FSDC
KW - CO2 separation membranes
KW - Scavenging effect of iron
KW - Permeability
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488612
DO - https://doi.org/10.3390/membranes9090108
SN - 2077-0375
VL - 9
IS - 9
SP - 108, 1
EP - 15
PB - MDPI
AN - OPUS4-48861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Joseba Ayerdi, J.
A1 - Slachciak, Nadine
A1 - Llavori, I.
A1 - Zabala, A.
A1 - Aginagalde, A.
A1 - Bonse, Jörn
A1 - Spaltmann, Dirk
T1 - On the role of a ZDDP in the tribological performance of femtosecond laser-induced periodic surface structures on titanium alloy against different counterbody materials
N2 - Laser-induced periodic surface structures (LIPSS, ripples) with ~500–700 nm period were produced on titanium alloy (Ti6Al4V) surfaces upon scan processing in air by a Ti:sapphire femtosecond laser. The tribological performance of the surfaces were qualified in linear reciprocating sliding tribological tests against balls made of different materials using different oilbased lubricants. Extending our previous work, we studied the admixture of the additive 2-ethylhexyl-zinc-dithiophosphate to a base oil containing only anti-oxidants and temperature stabilizers. The presence of this additive along with the variation of the chemical composition of the counterbodies allows us to explore the synergy of the additive with the laseroxidized nanostructures.
KW - Additives
KW - Surface structures
KW - Wear
KW - Friction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488458
DO - https://doi.org/10.3390/lubricants7090079
SN - 2075-4442
VL - 7
SP - 79, 1
EP - 13
PB - MDPI
AN - OPUS4-48845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schütz, R.
A1 - Maragh, J.
A1 - Weaver, J.
A1 - Rabin, Ira
A1 - Masic, A.
T1 - The Temple Scroll: Reconstructing an ancient manufacturing practice
N2 - The miraculously preserved 2000-year-old Dead Sea Scrolls, ancient texts of invaluable historical significance, were discovered in the mid-20th century in the caves of the Judean desert. The texts were mainly written on parchment and exhibit vast diversity in their states of preservation. One particular scroll, the 8-m-long Temple Scroll is especially notable because of its exceptional thinness and bright ivory color. The parchment has a layered structure, consisting of a collagenous base material and an atypical inorganic overlayer. We analyzed the chemistry of the inorganic layer using x-ray and Raman spectroscopies and discovered a variety of evaporitic sulfate salts. This points toward a unique ancient production technology in which the parchment was modified through the addition of the inorganic layer as a writing surface. Furthermore, understanding the properties of these minerals is particularly critical for the development of suitable conservation methods for the preservation of these invaluable historical documents.
KW - Temple Scroll
KW - Dead Sea Scrolls
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-495314
DO - https://doi.org/10.1126/sciadv.aaw7494
VL - 5
IS - 9
SP - 1
EP - 9
PB - AAAS
AN - OPUS4-49531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Staude, Andreas
A1 - Scholtz, G.
A1 - Dunlop, J. A.
T1 - Trilobite compound eyes with crystalline cones and rhabdoms show mandibulate affinities
N2 - Most knowledge about the structure, function, and evolution of early compound eyes is based on investigations in trilobites. However, these studies dealt mainly with the cuticular lenses and little was known about internal anatomy. Only recently some data on crystalline cones and retinula cells were reported for a Cambrian trilobite species. Here, we describe internal eye structures of two other trilobite genera. The Ordovician Asaphus sp. reveals preserved crystalline cones situated underneath the cuticular lenses. The same is true for the Devonian species Archegonus (Waribole) warsteinensis, which in addition shows the fine structure of the rhabdom in the retinula cells. These results suggest that an apposition eye with a crystalline cone is ancestral for Trilobita. The overall similarity of trilobite eyes to those of myriapods, crustaceans, and hexapods corroborates views of a phylogenetic position of trilobites in the stem lineage of Mandibulata.
KW - Coputed tomography
KW - Crystalline cones
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483889
DO - https://doi.org/10.1038/s41467-019-10459-8
SN - 2041-1723
VL - 10
SP - 2503, 1
EP - 7
PB - Nature
AN - OPUS4-48388
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Marc Benjamin
T1 - Temperature in micromagnetism: Cell size and scaling effects of the stochastic Landau-Lifshitz equation
N2 - The movement of the macroscopic magnetic moment in ferromagnetic systems can be described by the Landau-Lifshitz (LL) or Landau-Lifshitz-Gilbert (LLG) equation. These equations are strictly valid only at absolute zero temperature. To include temperature effects a stochastic version of the LL or LLG equation for a spin density of one per unit cell can be used instead. To apply the stochastic LL to micromagnetic simulations, where the spin density per unit cell is generally higher, a conversion regarding simulation cell size and temperature has to be established. Based on energetic considerations, a conversion for ferromagnetic bulk and thin film systems is proposed. The conversion is tested in micromagnetic simulations which are performed with the Object Oriented Micromagnetic Framework (OOMMF). The Curie temperatures of bulk Nickel, Cobalt and Iron systems as well as Nickel thin-film systems with thicknesses between 6.3 mono layer (ML) and 31ML are determined from micromagnetic simulations. The results show a good agreement with experimentally determined Curie temperatures of bulk and thin film systems when temperature scaling is performed according to the presented model.
KW - Micromagnetism
KW - LLG
KW - LL equation
KW - Landau Lifshitz equation
KW - Landau Lifshitz Gilbert equation
KW - Stochastic Landau Lifshitz equation
KW - Stochastic Landau Lifshitz Gilbert equation
KW - Curie temperature
KW - Magnetic Nanoparticles
KW - Thin film systems
KW - Temeprature scaling
KW - Phase transition
KW - Magnet coupling
KW - Ferromagnetism
KW - Superparamagnetism
KW - Paramagnetism
KW - Ni
KW - Co
KW - Fe
KW - Steel
KW - Nickel
KW - Cobalt
KW - Iron
KW - Temperature effects
KW - Cell size
KW - Damping factor
KW - Gamma
KW - Alpha
KW - Spin
KW - Magnetic moment
KW - Magnetic interacion
KW - Magnetization dynamics
KW - Domain wall
KW - Exchange length
KW - temeprature dependent exchange length
KW - Bloch wall
KW - Neel wall
KW - Exchange interaction
KW - Magnetic anisotropy
KW - Simulation
KW - OOMMF
KW - Object oriented micromagnetic framework
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484610
DO - https://doi.org/10.1088/2399-6528/ab31e6
VL - 3
IS - 7
SP - 075009-1
EP - 075009-8
PB - IOPscience
CY - England
AN - OPUS4-48461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Blaeß, Carsten
A1 - Müller, Ralf
A1 - Poologasundarampilai, G.
A1 - Brauer, D. S.
T1 - Sintering and concomitant crystallization of bioactive glasses
N2 - The sintering of bioactive glasses allows for the preparation of complex structures, such as three‐dimensional porous scaffolds. Such 3D constructs are particularly interesting for clinical applications of bioactive glasses in bone regeneration, as the scaffolds can act as a guide for in‐growing bone cells, allowing for good Integration with existing and newly formed tissue while the scaffold slowly degrades. Owing to the pronounced tendency of many bioactive glasses to crystallize upon heat treatment, 3D scaffolds have not been much exploited commercially. Here, we investigate the influence of crystallization on the sintering behavior of several bioactive glasses. In a series of mixed‐alkali glasses an increased CaO/alkali metal oxide Ratio improved sintering compared to Bioglass 45S5, where dense sintering was inhibited.
Addition of small amounts of calcium fluoride helped to keep melting and sintering temperatures low. Unlike glass 13‐93, these new glasses crystallized during sintering but this did not prevent densification. Variation in bioactive glass particle size allowed for fine‐tuning the microporosity resulting from the sintering process.
KW - Bioactive glass
KW - Crystallization
KW - Scaffolds
KW - Sintering
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485458
DO - https://doi.org/10.1111/ijag.13477
SN - 2041-1286
VL - 10
IS - 4
SP - 449
EP - 462
PB - Wiley
AN - OPUS4-48545
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, J.
A1 - Tarábek, J.
A1 - Kulkarni, R.
A1 - Wang, Cui
A1 - Dračínský, M.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Resch-Genger, Ute
A1 - Bojdys, M. J.
T1 - A π-conjugated, covalent phosphinine framework
N2 - Structural modularity of polymer frameworks is a key advantage of covalent organic polymers, however, only C, N, O, Si and S have found their way into their building blocks so far. Here, we expand the toolbox available to polymer and materials chemists by one additional nonmetal, phosphorus. Starting with a building block that contains a λ⁵‐phosphinine (C₅P) moiety, we evaluate a number of polymerisation protocols, finally obtaining a π‐conjugated, covalent phosphinine‐based framework (CPF‐1) via Suzuki‐Miyaura coupling. CPF‐1 is a weakly porous polymer glass (72.4 m2 g‐1 N2 BET at 77 K) with green fluorescence (λmax 546 nm) and extremely high thermal stability. The polymer catalyzes hydrogen evolution from water under UV and visible light irradiation without the need for additional co‐catalyst at a rate of 33.3 μmol h‐¹ g‐¹. Our results demonstrate for the first time the incorporation of the phosphinine motif into a complex polymer framework. Phosphinine‐based frameworks show promising electronic and optical properties that might spark future interest in their applications in light‐emitting devices and heterogeneous catalysis.
KW - Phosphinine
KW - Fully aromatic frameworks
KW - Suzuki-Miyaura coupling
KW - Polymers
KW - Fluorescence
KW - Small-angle scattering
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485330
DO - https://doi.org/10.1002/chem.201900281
SP - 2
EP - 10
PB - Wiley VCH-Verlag
CY - Weinheim
AN - OPUS4-48533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Woydt, Mathias
A1 - Huang, S.
A1 - Cannizza, E.
A1 - Vleugels, J.
A1 - Mohrbacher, H.
T1 - Niobium carbide for machining and wear protection - Evolution of properties
N2 - The sales of niobium carbide (NbC) have grown in the last years, but NbC is still a hidden carbide and mainly used as grain growth inhibitor in hard metals. In the present work it was shown that the progress in the key properties, like HV30, KIC and strength, followed by machining and tribological results of the respective NbC grades.
KW - Niobium carbide
KW - Hard metals
KW - Tribology
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485507
DO - https://doi.org/10.1016/j.mprp.2019.02.002
SN - 0026-0657
VL - 74
IS - 2
SP - 82
EP - 89
PB - Elsevier Ltd.
AN - OPUS4-48550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Brunet, G.
A1 - Marin, R.
A1 - Monk, Melissa-Jane
A1 - Galico, D. A.
A1 - Sigoli, F. A.
A1 - Suturina, E. A.
A1 - Hemmer, E.
A1 - Murugesu, M.
T1 - Exploring the dual functionality of an Ytterbium complex for luminescence thermometry and slow magnetic relaxation†
N2 - We present a comprehensive investigation of the magnetic and optical properties of an ytterbium complex, which combines two desirable and practical features into a single molecular system. Based upon YbIII Ions that promote near-infrared optical activity and a chemical backbone that is ideal for an in-depth understanding of the magnetic behaviour, we have designed a multifunctional opto-magnetic species that operates as a luminescent thermometer and as a single-molecule magnet (SMM). Our magnetic investigations, in conjunction with ab initio calculations, reveal one of the highest energy barriers reported for an YbIII-based complex. Moreover, we correlate this anisotropic barrier with the Emission spectrum of the compound, wherein we provide a complete assignment of the energetic profile of the complex. Such studies lay the foundation for the design of exciting multi-faceted materials that are able to retain information at the single-molecule level and possess built-in thermal self-monitoring capabilities.
KW - Magnetic
KW - Fluorescence
KW - NIR
KW - Temperature
KW - Dual sensing
KW - Sensor
KW - Yb(III) complex
KW - Lanthanide
KW - Quantum yield
KW - Quality assurance
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486659
DO - https://doi.org/10.1039/c9sc00343f
VL - 10
IS - 28
SP - 6799
EP - 6808
PB - Royal Society of Chemistry
AN - OPUS4-48665
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fletcher, D. C.
A1 - Hunter, R.
A1 - Xia, W.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Blackburn, E.
A1 - Kulak, A.
A1 - Xin, H.
A1 - Schnepp, Z.
T1 - Scalable synthesis of dispersible iron carbide (Fe3C) nanoparticles by ‘nanocasting’
N2 - Metal carbides have shown great promise in a wide range of applications due to their unique catalytic, electrocatalytic and magnetic properties. However, the scalable production of dispersible metal carbide nanoparticles remains a challenge. Here, we report a simple and scalable route to dispersible iron carbide (Fe3C) nanoparticles. This uses MgO nanoparticles as a removable ‘cast’ to synthesize Fe3C nanoparticles from Prussian blue (KFeIII[FeII(CN)6]). Electron tomography demonstrates how nanoparticles of the MgO cast encase the Fe3C nanoparticles to prevent sintering and agglomeration during the high-temperature synthesis. The MgO cast is readily removed with ethylenediaminetetraacetic acid (EDTA) to generate Fe3C nanoparticles that can be used to produce a colloidal ferrofluid or dispersed on a support material.
KW - Small-angle scattering
KW - SAXS
KW - Metal carbides
KW - Nanoparticles
KW - Nanocasting
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486295
DO - https://doi.org/10.1039/C9TA06876G
SN - 2050-7488
SN - 2050-7496
VL - 7
IS - 33
SP - 19506
EP - 19512
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-48629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Legall, Herbert
A1 - Schwanke, Christoph
A1 - Bonse, Jörn
A1 - Krüger, Jörg
T1 - The influence of processing parameters on X‑ray emission during ultra‑short pulse laser machining
N2 - During ultra-short laser material processing at high laser pulse repetition rates unwanted X-ray radiation can be generated in a quantity that may constitute a potential risk for health. An adequate X-ray radiation protection requires a thoroughly understanding of the influence of the laser processing parameters on the generation of X-ray radiation. In the present work, the generated X-ray dose during laser machining was investigated in air for varying beam scanning conditions at a pulse duration of 925 fs, a center wavelength of 1030 nm and a laser peak intensity of 2.6 × 10^14 W/cm^2. The X-ray radiation dose and the corresponding spectral X-ray emission were investigated in dependence on the laser’s pulse repetition rate and on the beam scanning speed. The results show a strong dependence of the X-ray emission on these laser processing parameters.
KW - Laser-induced X-ray emission
KW - Ultrashort laser material interaction
KW - Femtosecond laser
KW - Radiation protection
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486441
DO - https://doi.org/10.1007/s00339-019-2827-y
SN - 0947-8396
SN - 1432-0630
VL - 125
IS - 8
SP - 570, 1
EP - 8
PB - Springer
AN - OPUS4-48644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Woydt, Mathias
T1 - Sub-stoichiometric oxides for wear resistance
N2 - In the present work it was shown that the tribologcal profiles of special model oxides under dry unidirectional sliding have shown, that sub-oxides have a contribution to the tribological behavior of carbides and cermets, when they are tribo-oxidatively formed, because their tribological profiles as monolithic materials are homologous in part or totally, or compete with hardmetals or cermets, depending from the operating conditions regarded.
KW - Sub-oxide
KW - Friction
KW - Wear
KW - Carbide
KW - Hardmetal
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498154
DO - https://doi.org/10.1016/j.wear.2019.203104
SN - 0043-1648
N1 - Eine identische Version zu diesem Artikel wurde publiziert unter: Wear 438-439 (2019) 102735, https://doi.org/10.1016/j.wear.2019.01.066 - An identical version to this article was published under: Wear 438-439 (2019) 102735, https://doi.org/10.1016/j.wear.2019.01.066
VL - 440-441
SP - 203104-1
EP - 203104-7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-49815
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frielinghaus, H.
A1 - Butler, P. D.
A1 - Pauw, Brian Richard
A1 - Rennie, A. R.
T1 - Eleventh canSAS Meeting: International Cooperation and Collaboration in Small-Angle Scattering
N2 - The eleventh canSAS workshop was held in Freising, Germany, July 8–10, 2019.
These international meetings, promoting collective action for nomadic small-angle scatterers, have been taking place since 1998 and act as forums to catalyze cooperation amongst the SAS community in order to provide better facilities and equipment, combined with reliable data interpretation and analysis. The meeting attracted over 60 participants from major neutron and X-ray laboratories, as well as manufacturers of SAXS equipment, and users from academia and industry. There was also a wide geographical spread with participants from Australia, Asia, and North America joining European colleagues.
T2 - canSAS XI
CY - Freising, Germany
DA - 08.07-2019
KW - Small angle scattering
KW - Conference
KW - Standardisation
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-498192
DO - https://doi.org/10.1080/08940886.2019.1680215
SN - 0894-0886
SN - 1931-7344
VL - 32
IS - 6
SP - 48
EP - 49
PB - Taylor & Francis
CY - Abingdon, UK
AN - OPUS4-49819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berthold, J.
A1 - Vrana, J.
A1 - Heckel, Thomas
A1 - Kanzler, D.
A1 - Jatzlau, P.
A1 - Große, C.
T1 - Modellgestützte Bestimmung der Auffindwahrscheinlichkeit (POD) von Reflektoren bei der Ultraschallprüfung großer Schmiedeteile
N2 - Bruchmechanische Untersuchungen werden zur Vorhersage der Lebensdauer und der Wartungszyklen benutzt. Dabei wird davon ausgegangen, dass auch Objekte ohne detektierte Anzeigen Materialfehler mit einer Reflektivität kleiner der Nachweisgrenze aufweisen können. Keine detektierte Anzeige bedeutet daher für Bauteilauslegung, dass sie eine konservative Annahme machen müssen: es wird angenommen, dass das Bauteil Materialfehler in Größe der Nachweisgrenze enthält. Dies macht die Nachweisgrenze zu dem die Lebensdauer limitierenden Faktor. Bei probabilistischen Methoden wird zusätzliches Wissen, wie Zuverlässigkeit und Fehlerauffindwahrscheinlichkeiten bei der zerstörungsfreien Prüfung mit in die Berechnung einbezogen, um zu konservative Annahmen zu vermeiden. Ziel ist es eine Model-Assisted-POD aufzubauen mit der die reale volumetrische Ultraschallprüfung großer Schmiedeteile nachgebildet werden kann. Die resultierende POD soll im Weiteren in bruchmechanischen Betrachtungen Verwendung finden. In vorangegangenen Arbeiten [Preißel2015] wurde dazu der Einfluss des Prüfrasters nach der DGZfP-Richtlinie US 07:2014 auf die Fehlerauffindwahrscheinlichkeit (parametrisch) simulativ betrachtet und die Simulationstechnik experimentell validiert. In diesem Paper werden die Ergebnisse von Preißel überprüft und um eine Prüfraster-Summen-POD, die das Szenario der realen Bauteilprüfung beschreibt, erweitert. Zudem wird eine experimentell validierte, simulative, nicht-parametrische POD für schrägliegende Defekte aufgebaut. Schließlich werden erste Untersuchungen zur Defektmorphologie vorgestellt. Diese Arbeit ist im Rahmen eines Studenten-Stipendiums der DGZfP entstanden.
T2 - DGZfP DACH Tagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Schmiedeteile
KW - POD
KW - Ultraschall
KW - Zerstörungsfreie Prüfung
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496796
UR - http://www.ndt.net/?id=24529
VL - 24
IS - 8
SP - 1
EP - 12
PB - NDT.net
CY - Kirchwald
AN - OPUS4-49679
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heckel, Thomas
A1 - Bertovic, Marija
A1 - Rosenthal, Martina
A1 - Pavlovic, M.
A1 - Bartsch, L.
A1 - Muhs, V.
A1 - Holstein, R.
T1 - Zuverlässigkeitsbetrachtungen bei der Ultraschallprüfung von Radsatzwellen im Ausbildungsbetrieb
N2 - Im Rahmen der UT1-M1 Ausbildung im Ausbildungszentrum Wittenberge der DGZfP wurden statistische Untersuchungen am Beispiel der Radsatzwellenprüfung mit Testradsatzwellen durchgeführt. Diese Untersuchungen hatten zum Ziel, die wesentlichen Einflussparameter bei der Prüfung auf das Prüfergebnis zu evaluieren. Dabei wurde unter anderem die intrinsische Fähigkeit des Prüfverfahrens zum Auffinden verschiedener Reflektorgeometrien ermittelt. Die Ergebnisse der Handprüfung wurden mit Ergebnissen mechanisierter Prüfungen verglichen. Im Rahmen der Zuverlässigkeitsbetrachtung wurden die Probability of Detection (POD) und die Nachweisgrenzen ermittelt.
Ziel dieser Arbeit war es auch, menschliche und organisatorische Einflussfaktoren auf die Ultraschall-Handprüfung von Radsatzwellen zu identifizieren, um Empfehlungen zur Optimierung der Ausbildung auszuarbeiten. Dazu wurden prüfungsbezogene Risiken in der Praxis mittels Fehlzustandsart- und –auswirkungsanalyse (FMEA) analysiert sowie von den Prüfern empfundene Probleme während der Ausbildung und in der Praxis mittels Fragebogen identifiziert. Die Ergebnisse der FMEA haben gezeigt, dass während des gesamten Prozesses Fehler auftreten können, für die Gegenmaßnahmen getroffen und implementiert werden sollten. Aus den Hinweisen und Erkenntnissen wurden einige Empfehlungen zur Optimierung der Ausbildung erarbeitet.
T2 - DGZfP DACH Tagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Zuverlässigkeit
KW - Wellenprüfung
KW - Ultraschall
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496783
VL - 2019
SP - 1
EP - 11
AN - OPUS4-49678
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, L. M.
A1 - Simon, U.
A1 - Gurlo, A.
A1 - Smales, Glen Jacob
A1 - Bekheet, M. F.
T1 - Grafting and stabilization of ordered mesoporous silica COK-12 with graphene oxide for enhanced removal of methylene blue
N2 - Large-pore ordered mesoporous silica (OMS) COK-12, analogous to the well-known SBA-15, but synthesized in a more environmentally friendly way and exhibiting a shorter plate-like structure, was grafted with different amounts of graphene oxide (GO) for the first time in an inexpensive and rapid process, that was successfully upscaled. Samples were examined with nitrogen sorption analysis, SAXS, Raman spectroscopy, XPS, and zeta potential analysis. Adsorption experiments with the cationic dye methylene blue (MB) were conducted on the grafted materials and on pure COK-12, taking into account the influence of initial dye concentration (30–600 mg L-1), adsorbent dosage (0.2–14 g L-1), contact time (0.3–300 min), solution pH (4 10), and influence of salts and temperature (0–1 M NaCl, 80 C) to simulate industrial dye effluent. The adsorption process was found to be represented best by the Langmuir isotherm model, i.e., adsorption is a monolayer process. The calculated maximum Adsorption capacities were found to be 20.2 and 197.5 mg g-1 at dosages of 5 and 0.5 g L-1 for pure COK-12 and COK-12 grafted with 50 wt% GO, respectively, at pH 5.65 and MB concentration of 100 mg L-1.
Adsorption kinetics were found to follow the pseudo-second order model, i.e., chemisorption is the rate controlling step. The adsorption performances could be well preserved at simulated dye effluent.
Desorption was found to be most effective with hydrochloric acid. The COK-12 grafted with GO presented in this work shows superior adsorption properties in comparison to other grafted OMS materials. In addition, grafting with GO remarkably improved the stability of COK-12 in aqueous solution.
KW - COK-12
KW - Mesoporous Silica
KW - Graphene Oxide
KW - Large-pore
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497788
UR - https://pubs.rsc.org/en/content/articlehtml/2019/ra/c9ra05541j
DO - https://doi.org/10.1039/c9ra05541j
VL - 9
IS - 62
SP - 36271
EP - 36284
PB - Royal Society of Chemistry
AN - OPUS4-49778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kockert, M.
A1 - Mitdank, R.
A1 - Zykov, A.
A1 - Kowarik, Stefan
A1 - Fischer, F.
T1 - Absolute Seebeck coefficient of thin platinum films
N2 - The influence of size effects on the thermoelectric properties of thin platinum films is investigated and compared to the bulk. Structural properties, like the film thickness and the grain size, are varied. We correlate the electron mean free path with the temperature dependence of the electrical conductivity and the absolute Seebeck coefficient SPt of platinum. A measurement platform was developed as a standardized method to determine SPt and show that SPt,film is reduced compared to SPt,bulk. Boundary and surface scattering reduce the thermodiffusion and the phonon drag contribution to SPt,film by nearly the same factor. We discuss in detail on behalf of a model, which describes the temperature dependence of the absolute Seebeck coefficient, the influence of size effects of electron-phonon and phonon-phonon interaction on SPt.
KW - Thin magnetic films
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499007
DO - https://doi.org/10.1063/1.5101028
SN - 0021-8979
VL - 126
SP - 105106
PB - AIP
AN - OPUS4-49900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nirmalananthan-Budau, Nithiya
A1 - Rühle, Bastian
A1 - Geißler, Daniel
A1 - Moser, Marko
A1 - Kläber, Christopher
A1 - Schäfer, A.
A1 - Resch-Genger, Ute
T1 - Multimodal cleavable reporters for quantifying carboxy and amino groups on organic and inorganic nanoparticles
N2 - Organic and inorganic nanoparticles (NPs) are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. These applications require knowledge of the chemical nature, total number of surface groups, and the number of groups accessible for subsequent coupling of e.g., antifouling ligands, targeting bioligands, or sensor molecules. To establish the concept of catch-and-release assays, cleavable probes were rationally designed from a quantitatively cleavable disulfide moiety and the optically detectable reporter 2-thiopyridone (2-TP). For quantifying surface groups on nanomaterials, first, a set of monodisperse carboxy-and amino-functionalized, 100 nm-sized polymer and silica NPs with different surface group densities was synthesized. Subsequently, the accessible functional groups (FGs) were quantified via optical spectroscopy of the cleaved off reporter after its release in solution. Method validation was done with inductively coupled plasma optical emission spectroscopy (ICP-OES) utilizing the sulfur atom of the cleavable probe. This comparison underlined the reliability and versatility of our probes, which can be used for surface group quantification on all types of transparent, scattering, absorbing and/or fluorescent particles. The correlation between the total and accessible number of FGs quantified by conductometric titration, qNMR, and with our cleavable probes, together with the comparison to results of conjugation studies with differently sized biomolecules reveal the potential of catch-and-release reporters for surface analysis. Our findings also underline the importance of quantifying particularly the accessible amount of FGs for many applications of NPs in the life sciences.
KW - Advanced Materials
KW - Surface Chemistry
KW - Organic–inorganic nanostructures
KW - Funtional Groups
KW - Quantitative Analysis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499081
DO - https://doi.org/10.1038/s41598-019-53773-3
VL - 9
SP - 17577-1
EP - 17577-11
PB - Springer Nature
CY - London
AN - OPUS4-49908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritsch, Tobias
A1 - Sprengel, Maximilian
A1 - Evans, Alexander
A1 - Farahbod-Sternahl, L.
A1 - Saliwan Neumann, Romeo
A1 - Hofmann, M.
A1 - Bruno, Giovanni
T1 - On the determination of residual stresses in additively manufactured lattice structures
N2 - The determination of residual stresses becomes more complicated with increasing complexity of the structures investigated. Additive manufacturing techniques generally allow the production of ‘lattice structures’ without any additional manufacturing step. These lattice structures consist of thin struts and are thus susceptible to internal stress-induced distortion and even cracks. In most cases, internal stresses remain locked in the structures as residual stress.
The determination of the residual stress in lattice structures through nondestructive neutron diffraction is described in this work. It is shown how two difficulties can be overcome: (a) the correct alignment of the lattice structures within the neutron beam and (b) the correct determination of the residual stress field in a representative part of the structure. The magnitude and the direction of residual stress are discussed. The residual stress in the strut was found to be uniaxial and to follow the orientation of the strut, while the residual stress in the knots was more hydrostatic. Additionally, it is shown that strain measurements in at least seven independent directions are necessary for the estimation of the principal stress directions. The measurement directions should be chosen according to the sample geometry and an informed choice on the possible strain field. If the most prominent direction is not measured, the error in the calculated stress magnitude increases considerably.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Residual stress
KW - Principal stress components
KW - Neutron diffraction
KW - Lattice structures
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520663
DO - https://doi.org/10.1107/S1600576720015344
SN - 1600-5767
VL - 54
SP - 228
EP - 236
AN - OPUS4-52066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Fritsch, Tobias
A1 - Mishurova, Tatiana
A1 - Trofimov, Anton
A1 - Apel, D.
A1 - Ulbricht, Alexander
A1 - Kromm, Arne
A1 - Hesse, René
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - On the interplay of microstructure and residual stress in LPBF IN718
N2 - The relationship between residual stresses and microstructure associated with a laser powder bed fusion (LPBF) IN718 alloy has been investigated on specimens produced with three different scanning strategies (unidirectional Y-scan, 90° XY-scan, and 67° Rot-scan). Synchrotron X-ray energy-dispersive diffraction (EDXRD) combined with optical profilometry was used to study residual stress (RS) distribution and distortion upon removal of the specimens from the baseplate. The microstructural characterization of both the bulk and the nearsurface regions was conducted using scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD). On the top surfaces of the specimens, the highest RS values are observed in the Y-scan specimen and the lowest in the Rot-scan specimen, while the tendency is inversed on the side lateral surfaces. A considerable amount of RS remains in the specimens after their removal from the baseplate, especially in the Y- and Z-direction (short specimen Dimension and building direction (BD), respectively). The distortion measured on the top surface following baseplate thinning and subsequent removal is mainly attributed to the amount of RS released in the build direction. Importantly, it is observed that the additive manufacturing microstructures challenge the use of classic theoretical models for the calculation of diffraction elastic constants (DEC) required for diffraction-based RS analysis. It is found that when the Reuß model is used for the calculation of RS for different crystal planes, as opposed to the conventionally used Kröner model, the results exhibit lower scatter. This is discussed in context of experimental measurements of DEC available in the literature for conventional and additively manufactured Ni-base alloys.
KW - L-PBF IN718 material
KW - Effect of scanning strategies
KW - Near-surface X-ray diffraction
KW - Residual stress in AM
KW - Distortion upon baseplate removal
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519460
DO - https://doi.org/10.1007/s10853-020-05553-y
SN - 0022-2461
VL - 56
IS - 9
SP - 5845
EP - 5867
PB - Springer
AN - OPUS4-51946
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D.
A1 - Kozadayeva, M.
A1 - Manabaev, K.
A1 - Panin, A.
A1 - Sjöström, W.
A1 - Koptyug, A.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Meinel, Dietmar
A1 - Bruno, Giovanni
A1 - Cheneler, D.
A1 - Surmenev, R.
A1 - Surmeneva, M.
T1 - Different approaches for manufacturing Ti-6Al-4V alloy with triply periodic minimal surface sheet-based structures by electron beam melting
N2 - Targeting biomedical applications, Triply Periodic Minimal Surface (TPMS) gyroid sheet-based structures were successfully manufactured for the first time by Electron Beam Melting in two different production Themes, i.e., inputting a zero (Wafer Theme) and a 200 µm (Melt Theme) wall thickness. Initial assumption was that in both cases, EBM manufacturing should yield the structures with similar mechanical properties as in a Wafer-mode, as wall thickness is determined by the minimal beam spot size of ca 200 µm. Their surface morphology, geometry, and mechanical properties were investigated by means of electron microscopy (SEM), X-ray Computed Tomography (XCT), and uniaxial tests (both compression and tension). Application of different manufacturing Themes resulted in specimens with different wall thicknesses while quasi-elastic gradients for different Themes was found to be of 1.5 GPa, similar to the elastic modulus of human cortical bone tissue. The specific energy absorption at 50% strain was also similar for the two types of structures. Finite element simulations were also conducted to qualitatively analyze the deformation process and the stress distribution under mechanical load. Simulations demonstrated that in the elastic regime wall, regions oriented parallel to the load are primarily affected by deformation. We could conclude that gyroids manufactured in Wafer and Melt Themes are equally effective in mimicking mechanical properties of the bones.
KW - Electron beam melting
KW - Scaffold
KW - Lightweight structures
KW - Computed tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531595
DO - https://doi.org/10.3390/ma14174912
SN - 1996-1944
VL - 14
IS - 17
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-53159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evsevleev, Sergei
A1 - Mishurova, Tatiana
A1 - Khrapov, D.
A1 - Paveleva, A.
A1 - Meinel, Dietmar
A1 - Surmenev, R.
A1 - Surmeneva, M.
A1 - Koptyug, A.
A1 - Bruno, Giovanni
T1 - X-ray Computed Tomography Procedures to Quantitatively Characterize the Morphological Features of Triply Periodic Minimal Surface Structures
N2 - Additively manufactured (AM) metallic sheet-based Triply Periodic Minimal Surface Structures (TPMSS) meet several requirements in both bio-medical and engineering fields: Tunable mechanical properties, low sensitivity to manufacturing defects, mechanical stability, and high energy absorption. However, they also present some challenges related to quality control, which can prevent their successful application. In fact, the optimization of the AM process is impossible without considering structural characteristics as manufacturing accuracy, internal defects, as well as surface topography and roughness. In this study, the quantitative non-destructive analysis of TPMSS manufactured from Ti-6Al-4V alloy by electron beam melting was performed by means of X-ray computed tomography (XCT). Several advanced image analysis workflows are presented to evaluate the effect of build orientation on wall thicknesses distribution, wall degradation, and surface roughness reduction due to the chemical etching of TPMSS. It is shown that the manufacturing accuracy differs for the structural elements printed parallel and orthogonal to the manufactured layers. Different strategies for chemical etching show different powder removal capabilities and both lead to the loss of material and hence the gradient of the wall thickness. This affects the mechanical performance under compression by reduction of the yield stress. The positive effect of the chemical etching is the reduction of the surface roughness, which can potentially improve the fatigue properties of the components. Finally, XCT was used to correlate the amount of retained powder with the pore size of the functionally graded TPMSS, which can further improve the manufacturing process.
KW - Metamaterials
KW - Functionally graded porous structure
KW - Triply periodic minimal surface structures
KW - Roughness analysis
KW - Powder removal
KW - Deep learning segmentation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528142
DO - https://doi.org/10.3390/ma14113002
VL - 14
IS - 11
SP - 3002
PB - MDPI
AN - OPUS4-52814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Ulbricht, Alexander
A1 - Fritsch, Tobias
A1 - Mishurova, Tatiana
A1 - Kromm, Arne
A1 - Hofmann, M.
A1 - Wimpory, R. C.
A1 - Evans, Alexander
A1 - Bruno, Giovanni
T1 - Scanning Manufacturing Parameters Determining the Residual Stress State in LPBF IN718 Small Parts
N2 - The influence of scan strategy on the residual stress (RS) state of an as-built IN718 alloy produced by means of laser powder bed fusion (LPBF) is investigated. Two scan vector rotations (90°-alternation and 67°-rotation), each produced following two different scan vector lengths (long and short), are used to manufacture four rectangular prisms. Neutron diffraction (ND) and laboratory X-ray diffraction (XRD) techniques are used to map the bulk and surface RS state, respectively. The distortion induced upon removal from the baseplate is measured via profilometry. XRD measurements show that the two long scan vector strategies lead to higher RS when compared with the equivalent short scan vector strategies. Also, the 67°-rotation strategies generate lower RS than their 90°-alternation counterparts. Due to the lack of reliable stress-free d0 references, the ND results are analyzed using von Mises stress. In general, ND results show significant RS spatial non-uniformity. A comparison between ND and distortion results indicates that the RS component parallel to the building direction (Z-axis) has a predominant role in the Z-displacement. The use of a stress balance scheme allows to discuss the d0 variability along the length of the specimens, as well as examine the absolute RS state.
KW - As-built LPBF IN718 alloy
KW - Scan strategy influence
KW - Neutron diffraction
KW - Residual stress state
KW - Stress balance condition
KW - Distortion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526360
DO - https://doi.org/10.1002/adem.202100158
VL - 23
IS - 7
SP - 158
PB - Wiley
AN - OPUS4-52636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Paciornik, S.
A1 - Horvath, J.
A1 - Tushtev, K.
A1 - Rezwan, K.
A1 - Bruno, Giovanni
T1 - Evolution of Damage in All-Oxide Ceramic Matrix Composite After Cyclic Loading
N2 - While structural ceramics usually display a brittle mechanical behavior, their composites may show nonlinearities, mostly due to microcracking. Herein, the stiffness evolution of a sandwich-like laminate of an Al2O3 15%vol. ZrO2 matrix reinforced with Nextel 610 fibers is studied as a function of number of cycles N in tension. The stiffness of the composite degrades with increasing N, indicating microcracking. However, synchrotron X-ray refraction radiography shows that the internal specific surface of such cracks varies differently. A modeling strategy is developed for the calculation of the equivalent stiffness of mixtures (first the matrix and then the sandwich), based on the Voigt and Reuß schemes. The Bruno–Kachanov model is then used to estimate the initial microcrack density in the matrix (due to the thermal expansion mismatch) and the amount of microcracking increase upon cyclic loading. The stiffness in the composite degrades dramatically already after 20 000 cycles but then remains nearly constant. The combination of mechanical testing, quantitative imaging analysis, and modeling provides insights into the damage mechanisms acting: microcrack propagation is more active than microcrack initiation upon cyclic loading, but the second also occurs. This scenario is similar but not equal to previous results on porous and microcracked ceramics.
KW - Ceramic matrix composites
KW - Homogenization schemes
KW - Microcracking
KW - Nonlinear behavior
KW - Synchrotron X-ray refraction radiography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534541
DO - https://doi.org/10.1002/adem.202100763
SN - 1527-2648
SN - 1438-1656
VL - 24
IS - 6
SP - 2100763 -1
EP - 2100763 -13
PB - VCH GmbH
CY - Weinheim
AN - OPUS4-53454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauzon, C.
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Dubiez-Le Goff, S.
A1 - Murugesan, S.
A1 - Bruno, Giovanni
A1 - Hryha, E.
T1 - Residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion as a function of process atmosphere and component design
N2 - The influence of the process gas, laser scan speed, and sample thickness on the build-up of residual stresses and porosity in Ti-6Al-4V produced by laser powder bed fusion was studied. Pure argon and helium, as well as a mixture of those (30% helium), were employed to establish process atmospheres with a low residual Oxygen content of 100 ppm O2. The results highlight that the subsurface residual stresses measured by X-ray diffraction were significantly lower in the thin samples (220 MPa) than in the cuboid samples (645 MPa). This difference was attributed to the shorter laser vector length, resulting in heat accumulation and thus in-situ stress relief. The addition of helium to the process gas did not introduce additional subsurface residual stresses in the simple geometries, even for the increased scanning speed. Finally, larger deflection was found in the cantilever built under helium (after removal from the baseplate), than in those produced under argon and an argon-helium mixture. This result demonstrates that complex designs involving large scanned areas could be subjected to higher residual stress when manufactured under helium due to the gas’s high thermal conductivity, heat capacity, and thermal diffusivity.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Residual stress
KW - Process atmosphere
KW - Helium
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534209
DO - https://doi.org/10.1016/j.addma.2021.102340
VL - 47
SP - 2340
PB - Elsevier B.V.
AN - OPUS4-53420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritsch, Tobias
A1 - Farahbod-Sternahl, L.
A1 - Serrano-Munoz, Itziar
A1 - Léonard, F.
A1 - Haberland, C.
A1 - Bruno, Giovanni
T1 - 3D Computed Tomography Quantifies the Dependence of Bulk Porosity, Surface Roughness, and Re-Entrant Features on Build Angle in Additively Manufactured IN625 Lattice Struts
N2 - Layer-by-layer additive manufacturing (AM) by means of laser-powder bed Fusion (L-PBF) offers many prospects regarding the design of lattice structures used, for example, in gas turbines. However, defects such as bulk porosity, Surface roughness, and re-entrant features are exacerbated in nonvertical structures, such as tilted struts. The characterization and quantification of these kinds of
defects are essential for the correct estimation of fracture and fatigue properties.
Herein, cylindrical struts fabricated by L-PBF are investigated by means of X-ray computed tomography (XCT), with the aim of casting light on the dependence of the three kinds of defects (bulk porosity, surface roughness, and re-entrant features) on the build angle. Innovative analysis methods are proposed to correlate shape and position of pores, to determine the angular-resolved Surface roughness, and to quantify the amount of re-entrant surface features, q. A meshing of the XCT surface enables the correlation of q with the classical Surface roughness Pa. This analysis leads to the conclusion that there is a linear correlation between q and Pa. However, it is conjectured that there must be a threshold of surface roughness, below which no re-entrant features can be build.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Computed tomography
KW - Surface roughness analysis
KW - Re-entrant surface feature
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534728
DO - https://doi.org/10.1002/adem.202100689
IS - 2100689
SP - 1
EP - 8
PB - Wiley-VCH Verlag
AN - OPUS4-53472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Evans, Alexander
A1 - Mishurova, Tatiana
A1 - Sprengel, Maximilian
A1 - Pirling, T.
A1 - Kromm, Arne
A1 - Bruno, Giovanni
T1 - The importance of subsurface residual stress in laser powder bed fusion IN718
N2 - The residual stress (RS) in laser powder bed fusion (LPBF) IN718 alloy samples produced using a 67°-rotation scan strategy is investigated via laboratory X-ray diffraction (XRD) and neutron diffraction (ND). The location dependence of the strain-free (d₀) lattice spacing in ND is evaluated using a grid array of coupons extracted from the far-edge of the investigated specimen. No compositional spatial variation is observed in the grid array. The calculated RS fields show considerable non-uniformity, significant stress gradients in the region from 0.6 to 2 mm below the surface, as well as subsurface maxima that cannot be accounted for via XRD. It is concluded that failure to determine such maxima would hamper a quantitative determination of RS fields by means of the stress balance method.
KW - Laser powder bed fusion
KW - Neutron and X-ray diffraction
KW - Residual stress analysis
KW - Strain-free lattice references
KW - Stress balance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532707
DO - https://doi.org/10.1002/adem.202100895
SN - 1615-7508
SN - 1527-2648
VL - 24
IS - 6
SP - 1
EP - 7
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Magkos, Sotirios
A1 - Kupsch, Andreas
A1 - Bruno, Giovanni
T1 - Suppression of Cone-Beam Artefacts with Direct Iterative Reconstruction Computed Tomography Trajectories (DIRECTT)
N2 - The reconstruction of cone-beam computed tomography data using filtered back-projection algorithms unavoidably results in severe artefacts. We describe how the Direct Iterative Reconstruction of Computed Tomography Trajectories (DIRECTT) algorithm can be combined with a model of the artefacts for the reconstruction of such data. The implementation of DIRECTT results in reconstructed volumes of superior quality compared to the conventional algorithms.
KW - DIRECTT
KW - Iterative method
KW - Signal processing
KW - X-ray imaging
KW - Computed tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531085
DO - https://doi.org/10.3390/jimaging7080147
SN - 2313-433X)
VL - 7
IS - 8
SP - 147 - 1
EP - 147 -9
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-53108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pereira, Raíssa Monteiro
A1 - Lohbauer, Ulrich
A1 - Schulbert, Christian
A1 - Göken, Mathias
A1 - Wurmshuber, Michael
A1 - Campos, Tiago Bastos Moreira
A1 - Thim, Gilmar Patrocínio
A1 - Mieller, Björn
A1 - Belli, Renan
T1 - Instantiations of Multiscale Kinship in Pressing‐Defect Distributions in Yttria‐Stabilized Zirconias by Powder Partitioning
N2 - Modern dry pressing of ceramic powders using spray‐dried granulates cannot avoid the occurrence of defects related to persisting inter‐ and intra‐granulate interstitial voids. These constitute the parent defect size population limiting the application of polycrystalline ceramics in high‐stress conditions. The mitigation of such defects could widen the range of application in technical and biomedical engineering, reduce the safety range for design, and extend the lifetime of components. Herein, the Weibull size‐effect on strength in size‐partitioned Yttria‐stabilized zirconias (YSZ) feedstocks is used to explore the viability of changing the density distribution of granulate sizes as an effective strategy to obtain a denser particle packing that could reduce the size distribution of strength‐limiting pressing defects. In a direct assessment of critical defect size using multiscale strength testing with a dataset of ≈1300 values, the success of such an approach in increasing the strength reliability for small volume components is demonstrated, along with its ultimate failure in altering the defect size distribution in sintered YSZ ceramics across several length scales. Finally, it is shown that granule morphology (spherical or dimpled) fails to affect the defect density and size distribution in YSZ ceramics.
KW - Zirconia
KW - Strength
KW - Toughness
KW - Weibull distribution
KW - Defect population
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602697
DO - https://doi.org/10.1002/adem.202400139
SN - 1438-1656
SP - 1
EP - 17
PB - Wiley VHC-Verlag
AN - OPUS4-60269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silvestroni, L.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Ulbricht, Alexander
A1 - Wieder, Frank
A1 - Fritsch, Tobias
A1 - Sciti, D.
A1 - Bruno, Giovanni
T1 - Determination of short carbon fiber orientation in zirconium diboride ceramic matrix composites
N2 - In fiber-reinforced components, the fiber alignment and orientation have paramount influence on the thermomechanical properties of the resulting composite, for both short and continuous fiber. Here we present the case of an ultra-refractory matrix intended for extreme environment applications, ZrB2, reinforced with 20 vol% and 50 vol% short carbon fibers. In both cases, fibers tend to align perpendicular to the uniaxial pressure applied during shaping and sintering of a pellet, although the fiber tilt across the pellet thickness is difficult to determine. Moreover, for high volume fractions of reinforcement, the spatial distribution of the fibers is heterogeneous and tends to have domains of preferential orientations. We compare the information on the fiber distribution as collected by scanning electron microscopy images, X-ray computed tomography and synchrotron X-ray refraction radiography (SXRR). The three techniques prove to be complementary. Importantly, we demonstrate that SXRR yields the most statistically significant information due to the largest field of view, yet with a sensitivity down to the nanometer, and that can be successfully applied also to heavy matrix materials, such as zirconium boride.
KW - Ceramic matrix composites
KW - Synchrotron X-ray refraction radiography
KW - X-ray computed tomography
KW - Scanning electron microscopy
KW - High-temperature ceramics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597712
DO - https://doi.org/10.1016/j.jeurceramsoc.2024.02.048
SN - 0955-2219
VL - 44
IS - 8
SP - 4853
EP - 4862
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-59771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paulus, Daniel
A1 - Bresch, Sophie
A1 - Moos, Ralf
A1 - Schönauer-Kamin, Daniela
T1 - Powder aerosol deposited calcium cobaltite as textured P-type thermoelectric material with power factors approaching single crystal values
N2 - In this work, the thermoelectric material calcium cobaltite Ca3Co4O9 (CCO), a promising p-type conducting thermoelectric oxide with anisotropic properties, was processed by the powder aerosol deposition method (PAD) to form a dense ceramic CCO film with a thickness in the µm range. The prepared films were characterized regarding their microstructure and thermoelectric properties between room temperature and 900 °C. After heat treatment at 900 °C, the CCO PAD film in-plane shows excellent properties in terms of electrical conductivity (280 S/cm at 900 °C) and Seebeck coefficient (220 µV/K at 900 °C). The calculated power factor in-plane (ab) reaches with 1125 µW/(m K2) 40 % of the single crystal value, surpassing the known-properties of CCO bulk ceramics. Examination of the microstructure shows a strong fiber texture of the film as well as a strong coarsening of the grains during the first heat treatment up to 900 °C.
KW - thermoelectrics
KW - calcium cobaltite
KW - thermoelectric oxide
KW - aerosol deposition method (ADM)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606246
DO - https://doi.org/10.1016/j.jeurceramsoc.2024.116717
SN - 0955-2219
VL - 44
IS - 15
SP - 1
EP - 8
PB - Elsevier BV
AN - OPUS4-60624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mieller, Björn
A1 - Hassine, Sahar Ben
A1 - Töpfer, Jörg
A1 - Priese, Christoph
A1 - Bochmann, Arne
A1 - Capraro, Beate
A1 - Stark, Sebastian
A1 - Partsch, Uwe
A1 - Fresemann, Carina
T1 - Ontology‐based Data Acquisition, Refinement, and Utilization in the Development of a Multilayer Ferrite Inductor
N2 - A key aspect in the development of multilayer inductors is the magnetic permeability of the ferrite layers. Here, the effects of different processing steps on the permeability of a NiCuZn ferrite is investigated. Dry pressed, tape cast, and co‐fired multilayer samples are analyzed. An automated data pipeline is applied to structure the acquired experimental data according to a domain ontology based on PMDco (Platform MaterialDigital core ontology). Example queries to the ontology show how the determined process‐property correlations are accessible to non‐experts and thus how suitable data for component design can be identified. It is demonstrated how the inductance of co‐fired multilayer inductors is reliably predicted by simulations if the appropriate input data corresponding to the manufacturing process is used.This article is protected by copyright. All rights reserved.
KW - Ontology
KW - Ceramic multilayer
KW - Data pipeline
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605483
DO - https://doi.org/10.1002/adem.202401042
SN - 1527-2648
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-60548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mieller, Björn
A1 - Valavi, Masood
A1 - Caldeira Rêgo, Celso Ricardo
T1 - An Automatized Simulation Workflow for Powder Pressing Simulations Using SimStack
N2 - Automated computational workflows are a powerful concept that can improve the usability and reproducibility of simulation and data processing approaches. Although used very successfully in bioinformatics, workflow environments in materials science are currently commonly applied in the field of atomistic simulations. This work showcases the integration of a discrete element method (DEM) simulation of powder pressing in the convenient SimStack workflow environment. For this purpose, a Workflow active Node (WaNo) was developed to generate input scripts for the DEM solver using LIGGGHTS Open Source Discrete Element Method Particle Simulation code. Combining different WaNos in the SimStack framework makes it possible to build workflows and loop over different simulation or evaluation conditions. The functionality of the workflows is explained, and the added user value is discussed. The procedure presented here is an example and template for many other simulation methods and issues in materials science and engineering.
KW - Simulation workflow
KW - Discrete element method
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604791
DO - https://doi.org/10.1002/adem.202400872
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-60479
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, Michela
A1 - Tsamos, Athanasios
A1 - Faglioni, Francesco
A1 - Fioresi, Rita
A1 - Zanchetta, Ferdinando
A1 - Bruno, Giovanni
T1 - Geometric deep learning for enhanced quantitative analysis of microstructures in X-ray computed tomography data
N2 - Quantitative microstructural analysis of XCT 3D images is key for quality assurance of materials and components. In this paper we implement a Graph Convolutional Neural Network (GCNN) architecture to segment a complex Al-Si Metal Matrix composite XCT volume (3D image). We train the model on a synthetic dataset and we assess its performance on both synthetic and experimental, manually-labeled, datasets. Our simple GCNN shows a comparable performance, measured via the Dice score, to more standard machine learning methods, but uses a greatly reduced number of parameters (less than 1/10 of parameters), features low training time, and needs little hardware resources. Our GCNN thus achieves a cost-effective reliable segmentation.
KW - Geometric deep learning
KW - Segmentation
KW - Microstructure
KW - X-ray computed tomography
KW - Al–Si metal matrix composites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602517
DO - https://doi.org/10.1007/s42452-024-05985-0
SN - 3004-9261
VL - 6
IS - 6
SP - 1
EP - 9
AN - OPUS4-60251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kardjilov, N
A1 - Manke, I
A1 - Hilger, A
A1 - Arlt, T
A1 - Bradbury, R
A1 - Markötter, Henning
A1 - Woracek, R
A1 - Strobel, M
A1 - Treimer, W
A1 - Banhart, J
T1 - The Neutron Imaging Instrument CONRAD — Post‐Operational Review
N2 - The neutron imaging instrument CONRAD was operated as a part of the user program of the research reactor BER‐II at Helmholtz‐Zentrum Berlin (HZB) from 2005 to 2020. The Instrument was designed to use the neutron flux from the cold source of the reactor, transported by a curved neutron guide. The pure cold neutron spectrum provided a great advantage in the use of different neutron optical components such as focusing lenses and guides, solid‐state polarizers, Monochromators and phase gratings. The flexible setup of the instrument allowed for implementation of new methods including wavelength‐selective, dark‐field, phase‐contrast and imaging with polarized neutrons. In summary, these developments helped to attract a large number of scientists and industrial customers, who were introduced to neutron imaging and subsequently contributed to the Expansion of the neutron imaging community.
KW - Neutron imaging
KW - Neutron scattering
KW - Neutron instrument
KW - Tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534190
DO - https://doi.org/10.3390/ jimaging7010011
VL - 7
IS - 11
SP - 7010011
PB - MDPI
AN - OPUS4-53419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peruzzi, N.
A1 - Galli, S.
A1 - Helmholz, H.
A1 - Kardjilov, N.
A1 - Krüger, D.
A1 - Markötter, Henning
A1 - Moosmann, J.
A1 - Orlov, D.
A1 - Prgomet, Z.
A1 - Willumeit-Römer, R.
A1 - Wennerberg, A.
A1 - Bech, M.
T1 - Multimodal ex vivo methods reveal that Gd-rich corrosion byproducts remain at the implant site of biodegradable Mg-Gd screws
N2 - Extensive research is being conducted on magnesium (Mg) alloys for bone implant manufacturing, due to their biocompatibility, biodegradability and mechanical properties. Gadolinium (Gd) is among the most promising alloying elements for property control in Mg alloy implants; however, its toxicity is contro- versial. Investigating Gd behavior during implant corrosion is thus of utmost importance. In this study, we analyzed the degradation byproducts at the implant site of biodegradable Mg-5Gd and Mg-10Gd implants after 12 weeks healing time, using a combination of different imaging techniques: histology, energy-dispersive x-ray spectroscopy (EDX), x-ray microcomputed tomography (μCT) and neutron μCT. The main finding has been that, at the healing time in exam, the corrosion appears to have involved only the Mg component, which has been substituted by calcium and phosphorus, while the Gd remains localized at the implant site. This was observed in 2D by means of EDX maps and extended to 3D with a novel application of neutron tomography. X-ray fluorescence analysis of the main excretory organs also did not reveal any measurable accumulation of Gd, further reinforcing the conclusion that very limited or no removal at all of Gd-alloy happened during degradation.
KW - Magnesium-gadolinium alloy
KW - Biodegradable implant
KW - Multimodal analysis
KW - Energy-dispersive x-ray spectroscopy
KW - Micro-computed tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535910
DO - https://doi.org/10.1016/j.actbio.2021.09.047
SN - 1742-7061
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-53591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sprengel, Maximilian
A1 - Ulbricht, Alexander
A1 - Evans, Alexander
A1 - Kromm, Arne
A1 - Sommer, Konstantin
A1 - Werner, Tiago
A1 - Kelleher, J.
A1 - Bruno, Giovanni
A1 - Kannengießer, Thomas
T1 - Towards the optimization of post-laser powder bed fusion stress-relieve treatments of stainless steel 316L
N2 - This study reports on the stress relaxation potential of stress-relieving heat treatments for laser powder bed fused 316L. The residual stress is monitored non-destructively using neutron diffraction before and after the heat treatment. Moreover, the evolution of the microstructure is analysed using scanning electron microscopy. The results show, that a strong relaxation of the residual stress is obtained when applying a heat treatment temperature at 900°C. However, the loss of the cellular substructure needs to be considered when applying this heat treatment strategy.
KW - Residual stress
KW - Additive manufacturing
KW - Neutron diffraction
KW - Projekt AGIL - Alterung additiv gefertigter metallischer Materialien und Komponenten
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536045
DO - https://doi.org/10.1007/s11661-021-06472-6
SN - 1543-1940
VL - 52
IS - 12
SP - 5342
EP - 5356
PB - Springer
CY - Boston
AN - OPUS4-53604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauzon, C.
A1 - Mishurova, Tatiana
A1 - Fischer, M.
A1 - Ahlström, J.
A1 - Fritsch, Tobias
A1 - Bruno, Giovanni
A1 - Hryha, Eduard
T1 - Impact of contour scanning and helium-rich process gas on performances of Alloy 718 lattices produced by laser powder bed fusion
N2 - Contour scanning and process gas type are process parameters typically considered achieving second order effects compared to first order factors such as laser power and scanning speed. The present work highlights that contour scanning is crucial to ensure geometrical accuracy and thereby the high performance under uniaxial compression of complex Alloy 718 lattice structures. Studies of X-ray computed tomography visualizations of as-built and compression-strained structures reveal the continuous and smooth bending and compression of the walls, and the earlier onset of internal contact appearance in the denser lattices printed with contour. In contrast, the effect of addition of He to the Ar process gas appears to have limited influence on the mechanical response of the lattices and their microstructure as characterized by electron backscattered diffraction. However, the addition of He proved to significantly enhance the cooling rate and to reduce the amount of the generated spatters as evidenced by in situ monitoring of the process emissions, which is very promising for the process stability and powder reusability during laser powder bed fusion.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - Gyroid lattice
KW - Process atmosphere
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546632
DO - https://doi.org/10.1016/j.matdes.2022.110501
SN - 0264-1275
VL - 215
SP - 110501
PB - Elsevier Ltd.
AN - OPUS4-54663
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Léonard, F.
A1 - Lange, A.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - On the Morphological and Crystallographic Anisotropy of Diesel Particulate Filter Materials
N2 - The determination of the anisotropy of materials’ microstructure and morphology (pore space) in diesel particulate filter (DPF) materials is an important problem to solve, since such anisotropy determines the mechanical, thermal, and filtration properties of such materials. Through the use of a dedicated (and simple) segmentation algorithm, it is shown how to exploit the information yielded by 3D X-ray computed tomography data to quantify the morphological anisotropy. It is also correlated that such anisotropy of the pore space Such anisotropy of the pore space is also correlated with the microstructure and crystallographic anisotropy of the material in several showcases: a microstructurally isotropic material, such as SiC, and some morphologically and microstructurally anisotropic cordierite materials. In the later case, the finer the grain size, the more isotropic the microstructure.
KW - Diesel Particulate Filter Materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540705
DO - https://doi.org/10.1002/adem.202101380
VL - 24
IS - 2101380
SP - 1
EP - 12
PB - Wiley VCH GmbH
CY - Weinheim
AN - OPUS4-54070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Mieller, Björn
A1 - Mrkwitschka, Paul
A1 - Moos, R.
A1 - Rabe, Torsten
T1 - Glass-ceramic composites as insulation material for thermoelectric oxide multilayer generators
N2 - Thermoelectric generators can be used as energy harvesters for sensor applications.
Adapting the ceramic multilayer technology, their production can be
highly automated. In such multilayer thermoelectric generators, the electrical insulation material, which separates the thermoelectric legs, is crucial for the performance of the device. The insulationmaterial should be adapted to the thermoelectric regarding its averaged coefficient of thermal expansion α and its sintering temperature while maintaining a high resistivity.
In this study, starting from theoretical calculations, a glass-ceramic Composite material adapted for multilayer generators fromcalciummanganate and Calcium cobaltite is developed. The material is optimized towards an α of 11 × 10−6 K−1 (20–500◦C), a sintering temperature of 900◦C, and a high resistivity up to 800◦C.
Calculated and measured α are in good agreement. The chosen glass-ceramic composite with 45 vol.% quartz has a resistivity of 1 × 107 Ωcm and an open porosity of <3%. Sintered multilayer samples from tape-cast thermoelectric oxides and screen-printed insulation show only small reaction layers. It can be concluded that glass-ceramic composites are a well-suited material class for insulation layers as their physical properties can be tuned by varying glass composition or dispersion phases.
KW - Electrical insulators
KW - Glass-ceramics
KW - Multilayers
KW - Thermal expansion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538898
DO - https://doi.org/10.1111/jace.18235
SN - 0002-7820
SP - 1
EP - 10
PB - Wiley Online Library
AN - OPUS4-53889
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Schaupp, Thomas
A1 - Griesche, Axel
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Hannemann, Andreas
A1 - Kannengießer, Thomas
A1 - Bruno, Giovanni
T1 - Quantitative analysis of hydrogen-assisted microcracking in duplex stainless steel through X-ray refraction 3D imaging
N2 - While the problem of the identification of mechanisms of hydrogen assisted damage has and is being thoroughly studied, the quantitative analysis of such damage still lacks suitable tools. In fact, while, for instance, electron microscopy yields excellent characterization, the quantitative analysis of damage requires at the same time large field-of-views and high spatial resolution. Synchrotron X-ray refraction techniques do possess both features. In this work, we show how synchrotron X-ray refraction computed tomography (SXRCT) can quantify damage induced by hydrogen embrittlement in a lean duplex steel, yielding results that overperform even those achievable by synchrotron X-ray absorption computed tomography. As already reported in literature, but this time using a non-destructive technique, we show that the hydrogen charge does not penetrate to the center of tensile specimens. By the comparison between virgin and hydrogen-charged specimens, we deduce that cracks in the specimen bulk are due to the rolling process rather than hydrogen-assisted. We show that (micro)cracks propagate from the surface of tensile specimens to the interior with increasing applied strain, and we deduce that a significant crack propagation can only be observed short before rupture.
KW - 2101 duplex stainless steel
KW - Hydrogen embrittlement
KW - Synchrotron radiation
KW - X-ray refraction
KW - Computed tomography
KW - Microcracking
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542811
DO - https://doi.org/10.1002/adem.202101287
SN - 1438-1656
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54281
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Artzt, K.
A1 - Haubrich, J.
A1 - Sevostianov, I.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Micromechanical behavior of annealed Ti-6Al-4V produced by Laser Powder Bed Fusion
N2 - The micromechanical behavior of an annealed Ti-6Al-4V material produced by Laser Powder Bed Fusion was characterized by means of in-situ synchrotron X-ray diffraction during a tensile test. The lattice strain evolution was obtained parallel and transversal to the loading direction. The elastic constants were determined and compared with the conventionally manufactured alloy. In the plastic regime, a lower plastic anisotropy exhibited by the lattice planes was observed along the load axis (parallel to the building direction) than in the transverse direction.
Also, the load transfer from α to β phase was observed, increasing global ductility of the material. The material seems to accumulate a significant amount of intergranular strain in the transverse direction.
KW - Additive manufacturing
KW - Ti-6Al-4V
KW - Anisotropy
KW - Intergranular strain
KW - Synchrotron X-ray diffraction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547406
DO - https://doi.org/10.1080/26889277.2022.2063763
VL - 2
IS - 1
SP - 186
EP - 201
PB - Taylor & Francis
AN - OPUS4-54740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Oster, Simon
A1 - Ulbricht, Alexander
A1 - Bruno, Giovanni
T1 - Review on image registration methods for the quality control in additive manufacturing
N2 - A critical challenge in Additive Manufacturing is to ensure the safety and dimensional accuracy of produced parts. Since quality control is made by means of different online and offline imaging techniques (e.g. Thermography, X-ray and Optical Computer Tomography), image registration plays an important role in addressing these challenges. This paper introduces the main motivation, challenges, and research gaps of image registration in Additive Manufacturing. Furthermore, it introduces the main transformations, registration methods, similarity matrices and accuracy measurement. The main aim of the paper is to present a comprehensive review on the available methods for image registration in Additive Manufacturing based on the measurement techniques. Various registration methods, including landmark-based, point cloud-based, image intensity-based, and shape-based techniques, are examined in their applications for quality control, defect detection, and distortion quantification.
KW - Image processing
KW - Image fusion
KW - Computed tomography
KW - Computer-aided design
KW - Additive manufacturing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624495
DO - https://doi.org/10.1007/s40964-024-00932-2
SN - 2363-9520
SP - 1
EP - 27
PB - Springer Science and Business Media LLC
AN - OPUS4-62449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Popiela, Bartosz
A1 - Günzel, Stephan
A1 - Sklorz, Christian
A1 - Widjaja, Martinus Putra
A1 - Mair, Georg W.
A1 - Seidlitz, Holger
T1 - Application of the incremental hole-drilling method for residual stress determination in type 4 pressure vessels
N2 - Hole-drilling method is a standardized technique for obtaining residual stresses in isotropic structures. Previous studies provide a foundation that enables the use of this method to investigate orthotropic structures, such as fiber-reinforced composites. In this study, the incremental hole-drilling method was applied to investigate residual stresses in filament wound type 4 composite pressure vessels. The investigated composite cylinders were manufactured with different internal pressure functions during the winding process, to achieve distinct residual stress states. Additionally, the influence of the initial loading under sustained internal pressure and increased temperature on the stress distribution was investigated. It was shown that the residual stress state can be influenced by varying the internal pressure in the winding process. After testing at sustained load and increased temperature, a stress redistribution was observed, which took place due to creep phenomena. Finally, a discussion of the challenges for the application of the hole-drilling method to composite pressure vessels is provided.
KW - Hole-drilling method
KW - Filament winding
KW - Type 4 composite pressure vessels
KW - Residual stresses
KW - Stress redistribution
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627765
DO - https://doi.org/10.1515/mt-2024-0328
SN - 2195-8572
VL - 67
IS - 4
SP - 663
EP - 674
PB - Walter de Gruyter GmbH
AN - OPUS4-62776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Fritsch, Tobias
A1 - Ferrari, Bruno
A1 - Altmann, Mika León
A1 - Bruno, Giovanni
A1 - Toenjes, Anastasiya
T1 - Laser powder bed fusion: Defect type influences critical porosity re-growth during reheating after hot isostatic pressing
N2 - Despite the remarkable product design flexibility offered by additive manufacturing (AM) techniques, such as laser powder bed fusion, AM processes are susceptible to the formation of defects. In this context, the control of process parameters and the application of post-processing treatments, such as hot isostatic pressing (HIP), are of paramount importance to achieve the desired mechanical properties. The present study investigates the effectiveness of HIP as a function of process parameters in laser powder bed fused Ti-6V-4Al (PBF-LB/Ti64) using X-ray computed tomography. The process parameters are modified to obtain reference samples with low porosity, lack of fusion defects, or keyhole porosity. In all instances, subsurface keyhole porosity was observed in the as-built parts. Moreover, it was found that the efficacy of pore closure is dependent on the specific defect type. In the case of low porosity and keyhole pores, HIP resulted in effective closure. Conversely, larger lack of fusion defects were not closed due to their interconnectivity and the entrapment of argon gas. Subsequent heat treatments above the β-transus temperature allowed the investigation of the impact of defect type on porosity re-growth. For the first time, we reveal that lack of fusion defects are affected by considerable pore re-growth during post-HIP heat treatments of PBF-LB/Ti64. Such phenomenon is driven by the increasing internal pore pressure and local creep deformation at high temperatures. In contrast, re-growth is limited in samples with low porosity or keyhole pores.
KW - Additive Manufacturing
KW - Hot Isostatic Pressing
KW - Titanium
KW - Laser Powder Bed Fusion
KW - X-ray Computed Tomography
KW - Heat Treatment
KW - Porosity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629289
DO - https://doi.org/10.1016/j.jmatprotec.2025.118839
VL - 340
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-62928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Oster, Simon
A1 - Ulbricht, Alexander
A1 - Poka, Konstantin
A1 - Bruno, Giovanni
T1 - A Comparative Study of Rigid Three-Dimensional Image Registration Methods for Powder Bed Fusion with Laser Beam of Metals Using a Gold Standard Approach
N2 - In Additive Manufacturing (AM), precise rigid three-dimensional (3D) image registration between X-ray Computed Tomography (XCT) scans and Computer-Aided Design (CAD) models is an important step for the quantification of distortions in produced parts. Given the absence of standardized benchmarks for image registration in AM, we introduce a gold standard for 3D image registration, using a reference base plate beneath the build structure. This gold standard is used to quantify the accuracy of rigid registration, with a proof of concept demonstrated in PBF-LB/M. In this study, we conduct a comparative analysis of various rigid 3D registration methods useful for quality assurance of PBF-LB/M parts including feature-based, intensity-based, and point cloud-based approaches. The performance of each registration method is evaluated using measures of alignment accuracy based on the gold standard and computational efficiency. Our results indicate significant differences in the efficacy of these methods, with point cloud based Coherent Point Drift (CPD) showing superior performance in both alignment and computational efficiency. The rigidly registered 3D volumes are used to estimate the deformation field of the printed parts relative to the nominal CAD design using Digital Volume Correlation (DVC). The quality of the estimated deformation field is assessed using the Dice score metric. This study provides insights into methods for enhancing the precision and reliability of AM process.
KW - Digital volume correlation
KW - 3D image registration
KW - 3D image processing
KW - X-ray computed tomography
KW - Computer-aided design
KW - Displacement field estimation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627043
DO - https://doi.org/10.1007/s10921-025-01174-0
SN - 1573-4862
VL - 44
IS - 30
SP - 1
EP - 20
PB - Springer
AN - OPUS4-62704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fardan, Ahmed
A1 - Fazi, Andrea
A1 - Schröder, Jakob
A1 - Mishurova, Tatiana
A1 - Deckers, Tobias
A1 - Bruno, Giovanni
A1 - Thuvander, Matthias
A1 - Markström, Andreas
A1 - Brodin, Hakan
A1 - Hryha, Eduard
T1 - Microstructure tailoring for crack mitigation in CM247LC manufactured by powder bed fusion – Laser beam
N2 - Tailored microstructures in powder bed fusion – laser beam (PBF-LB) can aid in crack mitigation of non-weldable Ni-base superalloys such as CM247LC. This study explores the effect of a range of stripe widths from 5 mm down to 0.2 mm to control solidification cracking, microstructure, and residual stress in CM247LC manufactured by PBF-LB. The decrease in melt pool depth with the reduction in stripe width from 5 to 0.2 mm promoted the < 100 > crystallographic texture along the build direction. The crack density measurements indicated that there is an increase from 0.62 mm/mm2 (5 mm) to 1.71 mm/mm2 (1 mm) followed by a decrease to 0.33 mm/mm2 (0.2 mm). Atom probe tomography investigations at high-angle grain boundaries revealed that there is higher Hf segregation in 0.2 mm stripe width when compared to 5 mm. This indicates that the cracking behavior is likely influenced by the grain boundary segregation which in turn is dependent on melt pool shape/size and mushy zone length indicated by accompanying simulations. Residual stress, measured by X-ray diffraction, decreased from 842 MPa (5 mm) to 690 MPa (1 mm), followed by an abnormal rise to 842 MPa (0.7 mm) and 875 MPa (0.5 mm). This residual stress behavior is likely associated with the cracks acting as a stress relief mechanism. However, the 0.2 mm stripe width exhibited the lowest stress of 647 MPa, suggesting a different mechanism for stress relief, possibly due to re-melting. These findings highlight the critical role of stripe width as a scan strategy in PBF-LB processing of crack-susceptible alloys.
KW - Additive manufacturing
KW - Residual stress
KW - Scanning strategy
KW - Non-weldable superalloy
KW - Solidification cracking
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624606
DO - https://doi.org/10.1016/j.addma.2025.104672
SN - 2214-7810
VL - 99
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-62460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Malladi, Sri Bala Aditya
A1 - Mishurova, Tatiana
A1 - Anilkumar, Vishnu
A1 - Mehta, Bharat
A1 - Evans, Alexander
A1 - Surreddi, Kumar Babu
T1 - Reducing plastic anisotropy through stress induced martensitic transformation in an additively manufactured metastable medium entropy alloy
N2 - Powder bed fusion laser beam (PBF-LB) is particularly effective for fabricating compositionally complex alloys such as high-entropy alloys (HEAs) or medium-entropy alloys (MEAs). Fabricating non-equiatomic metastable MEAs using PBF-LB can lead to the formation of unique microstructures that enhance the mechanical performance of these alloys. Nevertheless, plastic anisotropy in materials prepared by additive manufacturing routes including PBF-LB remains to be a technical challenge. This work presents the fabrication of a metastable non-equiatomic Co45Cr25(FeNi)30 MEA using PBF-LB. As-printed samples exhibited the formation of nano-scaled ε-martensite (HCP) phase along with the FCC phase. The HCP phase exhibited Shoji-Nishiyama orientation relationship with the FCC phase. High energy synchrotron X-ray diffraction (HEXRD) and electron backscatter diffraction (EBSD) in-situ tensile testing were employed to investigate the influence of the HCP phase on the alloy's deformation behavior. The presence of the HCP phase initiates stress-induced martensitic transformation well below the macroscopic yield strength. This transformation led to the non-linear stress and strain response for the FCC phase. Further straining resulted in significant load partitioning, with the HCP phase taking the majority of the load as it formed, significantly strain hardening the alloy and reducing the plastic anisotropy induced by texture in the as-printed material.
KW - Neutron Diffraction
KW - X-ray computed tomography
KW - Mechanical Properties
KW - Additive Manufacturing
KW - Residual stress
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630588
DO - https://doi.org/10.1016/j.msea.2025.148308
SN - 1873-4936
VL - 933
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-63058
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, M.
A1 - Tsamos, Athanasios
A1 - Faglion, F.
A1 - Fioresi, R.
A1 - Zanchetta, F.
A1 - Bruno, Giovanni
T1 - Vision GNN (ViG) architecture for a fine‑tuned segmentation of a complex Al–Si metal matrix composite XCT volume
N2 - In this paper, we implement a vision graph neural network (ViG) architecture to segment microstructures in X-ray computed tomography 3D data. Our ViG architecture is first trained on a synthetic augmented dataset, and then fine-tuned on experimental data to obtain an improved segmentation. Successively, we assess the accuracy of the segmentation on manually-labeled experimental slices. We exemplarily use the approach on a complex microstructure: a metal matrix composite, reinforced with two ceramic phases, intermetallic inclusions and a silicon network, in order to show the generality of our method. ViG model proves to be more efficient than U-Nets in adapting to new data when fine-tuned on a small portion of the experimental data. The fine-tuned ViG shows comparable performance to U-Nets, while largely reducing the number of trainable parameters, with the potential of greater adaptability and efficiency.
KW - X-ray Computed tomography
KW - Machine Learning
KW - Virtual XCT
KW - Segmentation
KW - Composites
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630593
DO - https://doi.org/10.1007/s10853-025-10834-5
SN - 1573-4803
VL - 60
SP - 6907
EP - 6921
PB - Springer
AN - OPUS4-63059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rahimi, A.
A1 - Coduri, M.
A1 - Fitch, A.
A1 - Vedani, M.
A1 - Schröder, J.
A1 - Bruno, Giovanni
A1 - Casati, R.
T1 - Synchrotron investigation of heat treatment effects on the 3D residual stress distribution in laser powder bed fused AlSi7Mg alloys
N2 - For the first time, we utilized synchrotron diffraction to determine 3D maps of residual stresses across the entire volume of thick AlSi7Mg alloy prisms produced by PBF-LB. Samples were subjected to different heat treatment processes: direct aging (T5), solution treatment, and solution treatment followed by aging (T6). The T6 heat treatment resulted in the lowest residual tensile strains, while the T5 treatment resulted in significantly higher residual strains. Maximum residual stresses decreased from the as-built condition to the T6 heat-treated specimen. Although the T5 condition provides greater strength, it also retains higher tensile residual stresses near the surface, which can negatively affect fatigue properties.
KW - Neutron Diffraction
KW - Residual Stress
KW - Large Scale Facilities
KW - Additive Manufacturing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631089
DO - https://doi.org/10.1016/j.matlet.2025.138742
SN - 0167-577X
VL - 396
SP - 1
EP - 5
PB - Elsevier B.V.
AN - OPUS4-63108
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tran, K. V.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Hilger, A.
A1 - Kockelmann, W.
A1 - Kelleher, J.
A1 - Puplampu, S. B.
A1 - Penumadu, D.
A1 - Tremsin, A. S.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Spectral neutron tomography
N2 - Combined three-dimensional (3D) mapping of (micro-)structures with elemental and crystalline phase variations is of significant importance for the characterization of materials. Neutron wavelength selective imaging is a spectral imaging technique that exploits unique contrast differences e.g. for mapping dissimilar elemental, isotope, or phase compositions, and has the particular advantage of being applicable to sample volumes on the meso- and macroscale. While being mostly applied as radiography (2D) so far, we herein report that the extension to tomography allows for the display of the full spectral information for every voxel and in 3D. The development is supported by example data from a continuous as well as a pulsed neutron source. As a practical example, we collected 4D data sets (3D + spectral) of plastically deformed metastable stainless steel and herein demonstrate an improved quantification strategy for crystalline phase fractions. These exemplary results illustrate that localized phase transformations can be quantified even in complex geometries within centimeter-sized samples, and we will discuss the limits and future prospects of the technique that is not limited to crystalline materials.
KW - 4D tomographic data
KW - Multi-energy CT
KW - Spectral CT
KW - Phase distribution
KW - Full-field phase tomography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521668
DO - https://doi.org/10.1016/j.mtadv.2021.100132
VL - 9
SP - 132
PB - Elsevier Ltd.
AN - OPUS4-52166
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bevilacqua, N.
A1 - Asset, T.
A1 - Schmid, M. A.
A1 - Markötter, Henning
A1 - Manke, I.
A1 - Atanassov, P.
A1 - Zeis, R.
T1 - Impact of catalyst layer morphology on the operation of high temperature PEM fuel cells
N2 - Electrochemical impedance spectroscopy (EIS) is a well-established method to analyze a polymer electrolyte membrane fuel cell (PEMFC). However, without further data processing, the impedance spectrum yields only qualitative insight into the mechanism and individual contribution of transport, kinetics, and ohmic losses to the overall fuel cell limitations. The distribution of relaxation times (DRT) method allows quantifying each of these polarization losses and evaluates their contribution to a given electrocatalyst's depreciated performances. We coupled this method with a detailed morphology study to investigate the impact of the 3D-structure on the processes occurring inside a high-temperature polymer electrolyte membrane fuel cell (HT-PEMFC). We tested a platinum catalyst (Pt/C), a platinum-cobalt alloy catalyst (Pt3Co/C), and a platinum group metal-free iron-nitrogen-carbon (Fe–N–C) catalyst. We found that the hampered mass transport in the latter is mainly responsible for its low performance in the MEA (along with its decreased intrinsic performances for the ORR reaction). The better performance of the alloy catalyst can be explained by both improved mass transport and a lower ORR resistance. Furthermore, single-cell tests show that the catalyst layer morphology influences the distribution of phosphoric acid during conditioning.
KW - High-temperature polymer electrolyte membrane fuel cell
KW - Platinum-free catalyst
KW - Mass transport
KW - Oxygen reduction reaction
KW - Distribution of relaxation times analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520917
DO - https://doi.org/10.1016/j.powera.2020.100042
VL - 7
SP - 100042
PB - Elsevier Ltd.
AN - OPUS4-52091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ziesche, R. F.
A1 - Robinson, J. B.
A1 - Markötter, Henning
A1 - Bradbury, R.
A1 - Tengattini, A.
A1 - Lenoir, N.
A1 - Helfen, L.
A1 - Kockelmann, W.
A1 - Kardjilov, N.
A1 - Manke, I.
A1 - Brett, D. J. L.
A1 - Shearing, P. R.
T1 - Editors’ Choice—4D Neutron and X-ray Tomography Studies of High Energy Density Primary Batteries: Part II. Multi-Modal Microscopy of LiSOCl2 Cells
N2 - The ability to track electrode degradation, both spatially and temporally, is fundamental to understand performance loss during operation of lithium batteries. X-ray computed tomography can be used to follow structural and morphological changes in electrodes; however, the direct detection of electrochemical processes related to metallic lithium is difficult due to the low sensitivity to the element. In this work, 4-dimensional neutron computed tomography, which shows high contrast for lithium, is used to directly quantify the lithium diffusion process in spirally wound Li/SOCl2 primary cells. The neutron dataset enables the quantification of the lithium transport from the anode and the accumulation inside the SOCl2 cathode to be locally resolved. Complementarity between the collected neutron and X-ray computed tomographies is shown and by applying both methods in concert we have observed lithium diffusion blocking by the LiCl protection layer and identified all cell components which are difficult to distinguish using one of the methods alone.
KW - Lithium-ion battery
KW - Room-temperature
KW - Thermal runaway
KW - Gas evolution
KW - Cells
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520890
DO - https://doi.org/10.1149/1945-7111/abbfd9
VL - 167
SP - 140509
PB - IOP Science
AN - OPUS4-52089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Mieller, Björn
A1 - Schönauer-Kamin, D.
A1 - Moos, R.
A1 - Reimann, T.
A1 - Giovannelli, F.
A1 - Rabe, Torsten
T1 - Influence of pressure and dwell time on pressure‐assisted sintering of calcium cobaltite
N2 - Calcium cobaltite Ca3Co4O9, abbreviated Co349, is a promising thermoelectric material for high‐temperature applications in air. Its anisotropic properties can be assigned to polycrystalline parts by texturing. Tape casting and pressure‐assisted sintering (PAS) are a possible future way for a cost‐effective mass‐production of thermoelectric generators. This study examines the influence of pressure and dwell time during PAS at 900°C of tape‐cast Co349 on texture and thermoelectric properties. Tape casting aligns lentoid Co349. PAS results in a textured Co349 microstructure with the thermoelectrically favorable ab‐direction perpendicular to the pressing direction. By pressure variation during sintering, the microstructure of Co349 can be tailored either toward a maximum figure of merit as required for energy harvesting or toward a maximum power factor as required for energy harvesting. Moderate pressure of 2.5 MPa results in 25% porosity and a textured microstructure with a figure of merit of 0.13 at 700°C, two times higher than the dry‐pressed, pressureless‐sintered reference. A pressure of 7.5 MPa leads to 94% density and a high power factor of 326 µW/mK2 at 800°C, which is 11 times higher than the dry‐pressed reference (30 MPa) from the same powder.
KW - Hot pressing
KW - Texture
KW - Thermoelectric properties
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515973
DO - https://doi.org/https://doi.org/10.1111/jace.17541
SN - 0002-7820
VL - 104
IS - 2
SP - 917
EP - 927
PB - Wiley Periodicals LLC
AN - OPUS4-51597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Altenburg, Simon
A1 - Sprengel, Maximilian
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Fritsch, Tobias
A1 - Mishurova, Tatiana
A1 - Serrano-Munoz, Itziar
A1 - Evans, Alexander
A1 - Hofmann, M.
A1 - Bruno, Giovanni
T1 - Separation of the Formation Mechanisms of Residual Stresses in LPBF 316L
N2 - Rapid cooling rates and steep temperature gradients are characteristic of additively manufactured parts and important factors for the residual stress formation. This study examined the influence of heat accumulation on the distribution of residual stress in two prisms produced by Laser Powder Bed Fusion (LPBF) of austenitic stainless steel 316L. The layers of the prisms were exposed using two different border fill scan strategies: one scanned from the centre to the perimeter and the other from the perimeter to the centre. The goal was to reveal the effect of different heat inputs on samples featuring the same solidification shrinkage. Residual stress was characterised in one plane perpendicular to the building direction at the mid height using Neutron and Lab X-ray diffraction. Thermography data obtained during the build process were analysed in order to correlate the cooling rates and apparent surface temperatures with the residual stress results. Optical microscopy and micro computed tomography were used to correlate defect populations with the residual stress distribution. The two scanning strategies led to residual stress distributions that were typical for additively manufactured components: compressive stresses in the bulk and tensile stresses at the surface. However, due to the different heat accumulation, the maximum residual stress levels differed. We concluded that solidification shrinkage plays a major role in determining the shape of the residual stress distribution, while the temperature gradient mechanism appears to determine the magnitude of peak residual stresses.
KW - Additive Manufacturing
KW - Laser Powder Bed Fusion
KW - LPBF
KW - AISI 316L
KW - Online Process Monitoring
KW - Thermography
KW - Residual Stress
KW - Neutron Diffraction
KW - X-ray Diffraction
KW - Computed Tomography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512903
DO - https://doi.org/10.3390/met10091234
VL - 10
IS - 9
PB - MDPI
CY - Basel
AN - OPUS4-51290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Höhne, Patrick
A1 - Mieller, Björn
A1 - Rabe, Torsten
T1 - Advancing spray granulation by ultrasound atomization
N2 - The influence of the atomization technique on the suitability of granules for dry pressing is the focus of the presented investigations. Therefore, destabilized alumina, zirconia, and zirconia toughened alumina (ZTA) slurries were spray dried and the obtained granules were used to fabricate green and finally sintered bodies for evaluation.
Granules made in a laboratory spray dryer with a two-fluid nozzle served as a reference. An ultrasonic atomizer was integrated into the same spray dryer and the influence on the granule properties was evaluated. Untapped bulk density, granule size distribution, and flowability are among the evaluated granule-related properties as well as the granule yield which is used as an indicator of the process efficiency.
Yield and flowability as most important granule properties are clearly improved when atomization is realized with ultrasound. The investigated sinter body properties include porosity, sinter body density, and biaxial strength and are as well positively affected by switching the atomization technique to ultrasound. Therefore, the Approach to improve the compressibility of granules by ultrasonic atomization, which leads to an improved microstructure, density, and strength of sintered bodies, has proven to be successful for single-component ceramics (alumina and zirconia) as well as for the multicomponent ceramic ZTA.
KW - Alumina
KW - Granules
KW - Spray drying
KW - Ultrasound
KW - Zirconia
KW - Zirconia-toughened alumina
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510696
DO - https://doi.org/10.1111/ijac.13534
VL - 17
IS - 5
SP - 2212
EP - 2219
AN - OPUS4-51069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Trappe, Volker
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging
N2 - Modern air-liners and wind turbine rotor blades are made up primarily of fiber reinforced plastics. Failure of these materials heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in situ non-destructive testing techniques. Here, we report in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics due to inter-fiber failure. An inhouse designed compact tensile testing machine with a load range up to 15 kN was integrated into the beamline. Since conventional radiographs do not reveal sufficient contrast to distinguish cracks due to inter-fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging (DEI) technique is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. This technique allows fast measurements over large fields-of-view and is ideal for in-situ investigations. Imaging and the tensile test are run at the highest possible frame rate (0.7 s-1 ) and the lowest possible strain rate (5.5∙10-4 s -1 ). For 0°/90° non-crimp fabrics, the first inter-fiber cracks occur at 380 MPa (strain 0.8 %). Prior to failure at about 760 MPa (strain 2.0 %), we observe the evolution of nearly equidistant (1 mm distance) cracks running across the entire sample in the fully damaged state.
KW - X-ray refraction
KW - Diffraction Enhanced Imaging
KW - Carbon Fiber Reinforced Plastics
KW - In situ tensile test
KW - Crack evolution
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515060
DO - https://doi.org/10.1088/1757-899X/942/1/012035
SN - 1757-8981
SN - 1757-899X
VL - 942
SP - 012035-1
EP - 012035-9
PB - IOP publishing
CY - Bristol, UK
AN - OPUS4-51506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Schob, D.
A1 - Léonard, Fabien
A1 - Müller, Bernd R.
A1 - Sagradov, I.
A1 - Roszak, R.
A1 - Sparr, H.
A1 - Franke, R.
A1 - Ziegenhorn, M.
A1 - Bruno, Giovanni
T1 - Bestimmung der Mikrostruktur und Simulation des Schädigungsverhaltens von lasergesintertem Polyamid 12 unter quasistatischer Zugbelastung
N2 - Um das Material- und Schädigungsverhalten von additiv gefertigtem Polyamid 12 (PA12) unter quasistatischer Belastung zu charakterisieren, wurden mechanische Tests und Röntgenverfahren zur Bestimmung der Mikrostruktur eingesetzt. Die Proben wurden nach dem Prinzip des Selektiven Lasersinterns (SLS) hergestellt. Unter quasistatischer Belastung mit Haltezeiten ergab sich ein viskoplastisches Materialverhalten. Im Zugversuch wurde eine maximale Zugfestigkeit von 40.6 MPa und eine Bruchdehnung von 7.4% beobachtet. Mittels Röntgenrefraktion wurde eine Erhöhung von inneren Oberflächen beobachtet, die senkrecht zur Zugrichtung orientiert sind. Die Analyse der Gesamtporosität aus Computertomographie-Messungen ergab keine Änderung infolge der Zugbelastung. Jedoch wurde eine bimodale Porengrößenverteilung und eine steigende Sphärizität festgestellt. Das Materialverhalten wurde mit dem Chaboche-Modell simuliert und ergab eine sehr gute Übereinstimmung mit den experimentellen Ergebnissen. Allerdings gestattet dieses Modell nicht, das Schädigungsverhalten abzubilden. Daher wurde zur Simulation des Schädigungsverhaltens das Modell gemäß dem Ansatz von Gurson, Tvergaard und Needleman unter Berücksichtigung der mikrostrukturellen Parameter erweitert. Der Schwerpunkt des Beitrags liegt auf den Röntgenverfahren zur experimentellen Bestimmung der Mikrostruktur.
T2 - DGZfP-Jahrestagung 2021
CY - Online meeting
DA - 10.05.2021
KW - Additive Fertigung (AM)
KW - Polyamid 12
KW - Röntgenrefraktion
KW - Computertomographie
KW - Numerische Simulation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526833
UR - https://jahrestagung.dgzfp.de/Portals/jt2021/bb/P16.pdf
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-52683
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Khrapov, D.
A1 - Surmeneva, M.
A1 - Koptioug, A.
A1 - Evsevleev, Sergei
A1 - Léonard, Fabien
A1 - Bruno, Giovanni
A1 - Surmenev, R.
T1 - X-ray computed tomography of multiple-layered scaffolds with controlled gradient cell lattice structures fabricated via additive manufacturing
N2 - In this paper we report on the characterization by X-ray computed tomography of calcium phosphate (CaP) and polycaprolactone (PCL) coatings on Ti-6Al-4V alloy scaffolds used as a material for medical implants. The cylindrical scaffold has greater porosity of the inner part than the external part, thus, mimicking trabecular and cortical bone, respectively. The prismatic scaffolds have uniform porosity. Surface of the scaffolds was modified with calcium phosphate (CaP) and polycaprolactone (PCL) by dip-coating to improve biocompatibility and mechanical properties. Computed tomography performed with X-ray and synchrotron radiation revealed the defects of structure and morphology of CaP and PCL coatings showing small platelet-like and spider-web-like structures, respectively.
KW - Mechanical Engineering
KW - Maskinteknik
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510763
DO - https://doi.org/10.1088/1742-6596/1145/1/012044
SN - 17426588
VL - 1145
SP - 012044
PB - IOP
AN - OPUS4-51076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
T1 - Brittle Materials in Mechanical Extremes
N2 - The goal of the Special Issue “Brittle Materials in Mechanical Extremes” was to spark a discussion of the analogies and the differences between different brittle materials, such as, for instance, ceramics and concrete. Indeed, the contributions to the Issue spanned from construction materials (asphalt and concrete) to structural ceramics, reaching as far as ice. The data shown in the issue were obtained by advanced microstructural techniques (microscopy, 3D imaging, etc.) and linked to mechanical properties (and their changes as a function of aging, composition, etc.). The description of the mechanical behavior of brittle materials under operational loads, for instance, concrete and ceramics under very high temperatures, offered an unconventional viewpoint on the behavior of brittle materials. This is not at all exhaustive, but a way to pave the road for intriguing and enriching comparisons.
KW - Microcracking
KW - Ceramics
KW - Concrete
KW - Asphalt
KW - Mechanicalproperties
KW - Microstructure
KW - Strength
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514558
DO - https://doi.org/10.3390/ma13204610
VL - 13
IS - 20
SP - 4610
PB - MDPI
CY - Basel
AN - OPUS4-51455
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yao, J.
A1 - Zhu, G.
A1 - Dong, K.
A1 - Osenberg, M.
A1 - Hilger, A.
A1 - Markötter, Henning
A1 - Ju, J.
A1 - Sun, F.
A1 - Manke, I.
A1 - Cui, G.
T1 - Progress and Perspective of Controlling Li Dendrites Growth in All-Solid-State Li Metal Batteries via External Physical Fields
N2 - Li dendrites penetration through solid electrolytes (SEs) challenges the development of solid-state Li batteries (SSLBs). To date, significant efforts are devoted to understand the mechanistic dynamics of Li dendrites nucleation, growth, and propagation in SEs, and various strategies that aim to alleviate and even inhibit Li dendrite formation have been proposed. Nevertheless, most of these conventional strategies require either additional material processing steps or new materials/layers that eventually increase battery cost and complexity. In contrast, using external fields, such as mechanical force, temperature physical field, electric field, pulse current, and even magnetic field to regulate Li dendrites penetration through SEs, seems to be one of the most cost-effective strategies. This review focuses on the current research progress of utilizing external physical fields in regulating Li dendrites growth in SSLBs. For this purpose, the mechanical properties of Li and SEs, as well as the experimental results that visually track Li penetration dynamics, are reviewed. Finally, the review ends with remaining open questions in future studies of Li dendrites growth and penetration in SEs. It is hoped this review can shed some light on understanding the complex Li dendrite issues in SSLBs and potentially guide their rational design for further development.
KW - Li dendrites
KW - Li dendrites penetration mechanisms
KW - Solid electrolytes
KW - Solid-state batteries
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588331
DO - https://doi.org/10.1002/aesr.202300165
SN - 2699-9412
SP - 1
EP - 44
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-58833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markötter, Henning
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Evsevleev, Sergei
A1 - Arlt, T.
A1 - Ulbricht, Alexander
A1 - Dayani, Shahabeddin
A1 - Bruno, Giovanni
T1 - A Review of X-Ray Imaging at the BAMline (BESSY II)
N2 - The hard X-ray beamline BAMline at BESSY II (Berlin, Germany) has now been in service for 20 years. Several improvements have been implemented in this time, and this review provides an overview of the imaging methods available at the BAMline. Besides classic full-field synchrotron X-ray computed tomography (SXCT), also absorption edge CT, synchrotron X-ray refraction radiography (SXRR), and synchrotron X-ray refraction tomography (SXRCT) are used for imaging. Moreover, virtually any of those techniques are currently coupled in situ or operando with ancillary equipment such as load rigs, furnaces, or potentiostats. Each of the available techniques is explained and both the current and the potential usage are described with corresponding examples. The potential use is manifold, the examples cover organic materials, composite materials, energy-related materials, biological samples, and materials related to additive manufacturing. The article includes published examples as well as some unpublished applications.
KW - Material science
KW - Radiography
KW - Refraction
KW - Tomography
KW - X-ray imaging
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572417
DO - https://doi.org/10.1002/adem.202201034
SN - 1438-1656
SP - 1
EP - 22
PB - Wiley VHC-Verlag
AN - OPUS4-57241
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - De la Hoz Alford, L.
A1 - Pecanha de Souza, C. G.
A1 - Paciornik, S.
A1 - d` Almeida, J. R. M.
A1 - Santos Leite, B.
A1 - Avila, H. C.
A1 - Léonard, F.
A1 - Bruno, Giovanni
T1 - Three-Dimensional Characterization of Polyurethane Foams Based on Biopolyols
N2 - Two biopolyol-based foams derived from banana leaves (BL) or stems (BS) were produced, and their compression mechanical behavior and 3D microstructure were characterized. Traditional compression and in situ tests were performed during 3D image acquisition using X-ray microtomography. A methodology of image acquisition, processing, and analysis was developed to discriminate the foam cells and measure their numbers, volumes, and shapes along with the compression steps.
The two foams had similar compression behaviors, but the average cell volume was five times larger for the BS foam than the BL foam. It was also shown that the number of cells increased with increasing compression while the average cell volume decreased. Cell shapes were elongated and did not change with compression. A possible explanation for these characteristics was proposed based on the possibility of cell collapse. The developed methodology will facilitate a broader study of biopolyol-based foams intending to verify the possibility of using these foams as green alternatives to the typical petrol-based foams.
KW - Compression mechanical
KW - Biopolyol
KW - Banana
KW - 3D microstructure
KW - X-ray microtomography
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571982
DO - https://doi.org/10.3390/ma16052118
SN - 1996-1944
VL - 16
IS - 5
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-57198
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mouiya, M.
A1 - Martynyuk, M.
A1 - Kupsch, Andreas
A1 - Laquai, R.
A1 - Müller, Bernd R.
A1 - Doyen, N.T.
A1 - Tamraoui, Y.
A1 - Serrano-Munoz, Itziar
A1 - Huger, M.
A1 - Kachanov, M.
A1 - Bruno, Giovanni
T1 - The stress–strain behavior of refractory microcracked aluminum titanate: The effect of zigzag microcracks and its modeling
N2 - The stress–strain behavior of ceramics, such as aluminum titanate, has certain features that are unusual for brittle materials—in particular, a substantial nonlinearity under uniaxial tension, and load–unload hysteresis caused by the sharp increase of the incremental stiffness at the beginning of unloading. These features are observed experimentally and are attributed to microcracking. Here we compare different degrees of stress–strain nonlinearity of aluminum titanate materials and quantitatively model them. We use advanced mechanical testing to observe the mechanical response at room and high temperature; electron microscopy, and X-ray refraction radiography to observe the microstructural changes. Experiments show that two types of microcracks can be distinguished: (i) microcracks induced by cooling from the sintering temperature (due to heterogeneity and anisotropy of thermal expansion), with typical sizes of the order of grain size, and (ii) much larger microcracks generated by the mechanical loading. The two microcrack types produce different effects on the stress–strain curves. Such microcracks and the features of the stress–strain behavior depend on the density of the cooling-induced microcracks and on the distribution of grain sizes. They are modeled analytically and numerically.
KW - Hystersis
KW - Nonlinear stress-strain curve
KW - Refractory
KW - Stiffness
KW - X-ray refraction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580517
DO - https://doi.org/10.1111/jace.19325
SN - 1551-2916
VL - 106
SP - 6995
EP - 7008
PB - Wiley-Blackwell
CY - Oxford [u.a.]
AN - OPUS4-58051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Bernd R.
A1 - Kupsch, Andreas
A1 - Serrano-Munoz, Itziar
A1 - Laquai, René
A1 - Bruno, Giovanni
T1 - Anwendungen der Röntgenrefraktionstechnik zur zerstörungsfreien Charakterisierung von Keramiken und Verbundwerkstoffen
N2 - Die Brechung von Röntgenstrahlen (Röntgenrefraktion) an Grenzflächen zwischen Materialien unterschiedlicher Dichte ist analog zur Ablenk-ung von sichtbarem Licht an z.B. Glasoberflächen. Es gibt jedoch zwei wesentliche Unterschiede:
a) konvexe Grenzflächen verursachen Divergenz (d.h. der Brechungsindex n ist kleiner als 1), und
b) die Ablenkungswinkel sind sehr klein, und reichen von einigen Bogensekunden bis zu einigen Bogenminuten (d.h. n ist nahe bei 1);
Wie auch bei sichtbarem Licht ist die Ablenkungsrichtung der Röntgenstrahlen abhängig von der Orientierung der durchstrahlten Grenzfläche. Aufgrund dieser Eigenschaften eignen sich Röntgenrefraktionsmethoden hervorragend für:
a) die Erkennung und Quantifizierung von Defekten wie Poren und Mikrorissen und
b) die Bewertung von Porosität und Partikeleigenschaften wie Orientierung, Größe und räumliche Verteilung.
Wir zeigen die Anwendung der Röntgenrefraktionsradiographie (2,5D Technik) und der -tomographie (3D Technik) für die Untersuchung verschiedener Probleme in der Werkstoffwissenschaft und -technologie:
a) Sintern von SiC-Grünkörpern
b) Porositätsanalyse in Dieselpartikelfiltersilikaten
c) Faser-Matrix-Haftung in Metall- und Polymermatrixverbundwerkstoffen
d) Mikrorissbildung in Glaskeramik.
Wir zeigen, dass der Einsatz von Röntgenrefraktionsmethoden quantitative Ergebnisse liefert, die direkt als Parameter in Werkstoffmodellen verwendet werden können.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Röntgen-Refraktion
KW - Verbundwerkstoffe
KW - Keramik
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576171
UR - https://jahrestagung.dgzfp.de/Portals/jt2023/BB180/Inhalt/p9.pdf
UR - https://jahrestagung.dgzfp.de/Portals/jt2023/BB180/Inhalt/default.htm
SN - 978-3-947971-29-9
SP - 1
EP - 16
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-57617
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Evsevleev, Sergei
A1 - Piault, Pierre
A1 - King, Andrew
A1 - Henry, Laura
A1 - Bruno, Giovanni
T1 - Understanding the hot isostatic pressing efectiveness of laser powder bed fusion Ti‑6Al‑4V by in‑situ X‑ray imaging and difraction experiments
N2 - In the present study, in-situ observation of Hot Isostatic Pressure (HIP) procedure of laser powder bed fusion manufactured Ti-6Al-4V parts was performed to quantitatively estimate the densifcation rate of the material and the infuence of the defect initial size and shape on such rate. The observations were performed in-situ using the Ultrafast Tomography Paris-Edinburgh Cell and the combination of fast phase-contrast synchrotron X-ray tomography and energy dispersive difraction. With this strategy, we could quantify how the efectiveness of HIP depends on the characteristics of a defect. Smaller defects showed a higher densifcation rate, while the defect shape did not have signifcant efect on such rate.
KW - Additive manufacturing
KW - Laser powder bed fusion
KW - X-ray computed tomography
KW - Hot isostatic pressing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587702
DO - https://doi.org/10.1038/s41598-023-45258-1
SN - 2045-2322
VL - 13
IS - 1
SP - 1
EP - 11
AN - OPUS4-58770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fernández, R.
A1 - Bokuchava, G.
A1 - Bruno, Giovanni
A1 - Serrano-Munoz, Itziar
A1 - González Doncel, G.
T1 - On the dependence of creep-induced dislocation configurations on crystallographic orientation in pure Al and Al-Mg
N2 - The peak broadening in neutron diffraction experiments on tensile specimens of pure Al (99.8%) and an Al-Mg alloy pre-deformed at different creep strains is analysed. These results are combined with the kernel angular misorientation of electron backscatter diffraction data from the creep-deformed microstructures. It is found that differently oriented grains possess different microstrains. These microstrains vary with creep strain in pure Al, but not in the Al-Mg alloy. It is proposed that this behaviour can explain the power-law breakdown in pure Al and the large creep strain observed in Al-Mg. The present findings further corroborate a description of the creep-induced dislocation structure as a fractal, predicated on previous work.
KW - Creep
KW - Aluminium alloys
KW - Dislocations
KW - Fractals
KW - Diffraction peak width
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575527
DO - https://doi.org/10.1107/S1600576723003771
SN - 0021-8898
VL - 56
IS - Pt 3
SP - 764
EP - 775
AN - OPUS4-57552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Trappe, Volker
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Rissentwicklung in CFK-Laminaten nachgewiesen durch in situ Röntgen-Refraktion
N2 - In Leichtbauanwendungen sind Materialien mit geringen Dichten und hohen Festigkeiten gefragt. Insbesondere Faser-Kunststoff-Verbunde (FKV) erfüllen diese Anforderungen und werden zunehmend für Strukturbauteile eingesetzt. Die Oberflächen moderner Rotorblätter von Windkraftanlagen werden aus FKV gefertigt. Das Versagen dieser Materialien hat massiven Einfluss auf die Einsatzfähigkeit der gesamten Windkraftanlage. Daher ist die Kenntnis des Versagensverhaltens dieser Komponenten unter statischer und zyklischer Belastung von großem Interesse, um die Betriebsbeanspruchung abzuschätzen. Im Idealfall wird die Schadensentwicklung unter Betriebslast mit zerstörungsfreien in-situ-Prüfverfahren ermittelt. Hier berichten wir über die Beobachtung der Rissentwicklung in Carbon-Faserverstärkten Kunststoffen (CFK) unter kontinuierlicher Zugbelastung durch in-situ Synchrotron-Röntgenrefraktionsradiographie. Eine selbst entwickelte elektromechanische Zugprüfmaschine mit einem Kraftbereich bis zu 15 kN wurde in den Strahlengang an der BAMline (BESSY II) integriert. Da in herkömmlichen (Absorptions-) Radiographien Defekte wie Zwischenfaserbrüche oder Faser-Matrix-Enthaftung keinen ausreichenden Kontrast verursachen, wird zur Kontrastanhebung die Röntgenrefraktion benutzt. Hier wird das sogenannte Diffraction Enhanced Imaging (DEI) angewandt, um Primär- und gebrochene Strahlung mit Hilfe eines Analysatorkristalls zu trennen. Diese Technik ermöglicht schnelle Messungen mit einem Gesichtsfeld von einigen Quadratmillimetern (hier: 14 mm × 7.2 mm) und ist ideal für in-situ Untersuchungen. Die Bildgebung und der Zugversuch erfolgen mit einer Bildfrequenz von 0.7 / s und einer Dehnrate von 0.00055 / s . Bei 0°/90° Fasergelegen treten die ersten Zwischenfaserrisse bei 380 MPa (Dehnung 0.8 %) auf. Vor dem Versagen bei ca. 760 MPa (Dehnung 2.0 %) beobachten wir die Ausbildung eines nahezu äquidistanten Rissmusters (Risse in ca. 1 mm Abstand), das sich im geschädigten Zustand über die gesamte Probe erstreckt.
T2 - DACH-Jahrestagung 2023
CY - Friedrichshafen, Germany
DA - 15.05.2023
KW - Röntgen-Refraktion
KW - Synchrotronstrahlung
KW - CFK
KW - Rissentwicklung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576230
SN - 978-3-947971-29-9
VL - BB 180
SP - 1
EP - 8
AN - OPUS4-57623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Hejazi, Bardia
A1 - Poka, Konstantin
A1 - Bruno, Giovanni
T1 - Deep Learning Based 3D Volume Correlation for Additive Manufacturing Using High-Resolution Industrial X-Ray Computed Tomography
N2 - Quality control in Additive Manufacturing (AM) is vital for industrial applications in areas such as the automotive, medical, and aerospace sectors. Geometric inaccuracies caused by shrinkage and deformations can compromise the life and performance of additively manufactured components. Such deviations can be quantified using Digital Volume Correlation (DVC), which compares the Computer-Aided Design (CAD) model with the X-ray Computed Tomography (XCT) geometry of the components produced. However, accurate registration between the two modalities is challenging due to the absence of a ground truth or reference deformation field. In addition, the extremely large data size of high-resolution XCT volumes makes computation difficult. In this work, we present a deep learning-based approach for estimating voxel-wise deformations between CAD and XCT volumes. Our method uses a dynamic patch-based processing strategy to handle high-resolution volumes. In addition to the Dice score, we introduce a Binary Difference Map (BDM) that quantifies voxel-wise mismatches between binarized CAD and XCT volumes to evaluate the accuracy of the registration. Our approach shows a 9.2% improvement in the Dice score and a 9.9% improvement in the voxel match rate compared to classic DVC methods, while reducing the interaction time from days to minutes. This work sets the foundation for deep learning-based DVC methods to generate compensation meshes that can then be used in closed-loop correlations during the AM production process. Such a system would be of great interest to industry, as it would make the manufacturing process more reliable and efficient, saving time and material.
KW - Deep learning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646293
DO - https://doi.org/10.3233/FAIA251475
SN - 0922-6389
VL - 413
SP - 5368
EP - 5375
PB - IOS Press
AN - OPUS4-64629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Isaac, Augusta
A1 - Serrano‐Munoz, Itziar
A1 - Kostka, Aleksander
A1 - Widjaja, Martinus Putra
A1 - González‐Doncel, Gaspar
A1 - Bruno, Giovanni
A1 - Fernández, Ricardo
T1 - Subgrain and Cavity Development during Creep of Al‐3.85%Mg
N2 - It is classically considered that the creep mechanisms for type M (e.g., pure Al) and type A alloys (e.g., Al–Mg alloys) are different. In previous studies, it is predicated that fractal dislocation structures build up during creep can unify the creep behavior of pure Al and Al–Mg alloys. So far, good agreement between model and experimental data for pure Al is obtained. In this work, an Al‐3.85%Mg material crept at different strain levels (6%, 12%, 24%, and 35%) is analyzed by means of electron channelling contrast imaging. The formation of subgrains is observed at very large deformations (35%). Further examinations at 35% deformation, using electron backscatter diffraction, indicate that the subgrains and cavities tend to localize at regions where high intergranular stress mismatch is expected to occur. Laboratory X‐ray computed tomography is used to analyze the evolution of cavities between 12% and 24% stages, indicating that the fractal dimension of the cavities smaller than 100 μm varies with creep strain, as a reflection of the evolution of dislocation distribution. It is explained how the present data feed the model of the creep behavior of Al‐3.85%Mg.
KW - Al–Mg alloys
KW - Creep
KW - Dislocations
KW - Fractal
KW - Intergranular residual stress
KW - Subgrains
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645905
DO - https://doi.org/10.1002/adem.202500263
SN - 1438-1656
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-64590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pohl, P.
A1 - Kümmel, F.
A1 - Schunk, C.
A1 - Serrano-Munoz, Itziar
A1 - Markötter, Henning
A1 - Göken, M.
A1 - Höppel, H. W.
T1 - About the Role of Interfaces on the Fatigue Crack Propagation in Laminated Metallic Composites
N2 - The influence of gradients in hardness and elastic properties at interfaces of dissimilar materials in laminated metallic composites (LMCs) on fatigue crack propagation is investigated experimentally for three different LMC systems: Al/Al-LMCs with dissimilar yield stress and Al/Steel-LMCs as well as Al/Ti/Steel-LMCs with dissimilar yield stress and Young’s modulus, respectively. The damage tolerant fatigue behavior in Al/Al-LMCs with an alternating layer structure is enhanced significantly compared to constituent monolithic materials. The prevalent toughening mechanisms at the interfaces are identified by microscopical methods and synchrotron X-ray computed tomography. For the soft/hard transition, crack deflection mechanisms at the vicinity of the interface are observed, whereas crack bifurcation mechanisms can be seen for the hard/soft transition. The crack propagation in Al/Steel-LMCs was studied conducting in-situ scanning electron microscope (SEM) experiments in the respective low cycle fatigue (LCF) and high cycle fatigue (HCF) regimes of the laminate. The enhanced resistance against crack propagation in the LCF regime is attributed to the prevalent stress redistribution, crack deflection, and crack bridging mechanisms. The fatigue properties of different Al/Ti/Steel-LMC systems show the potential of LMCs in terms of an appropriate selection of constituents in combination with an optimized architecture. The results are also discussed under the aspect of tailored lightweight applications subjected to cyclic loading.
KW - Laminated metallic composites
KW - Toughening mechanisms
KW - Interfaces
KW - Fatigue crack propagation
KW - Fatigue crack growth
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526531
DO - https://doi.org/10.3390/ma14102564
VL - 14
IS - 10
SP - 2564
PB - MDPI
AN - OPUS4-52653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silveira, A.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Longo, E.
A1 - Greving, I.
A1 - Lasch, P.
A1 - Shahar, R
A1 - Zaslansky, P.
T1 - Water flow through bone: Neutron tomography reveals differences in water permeability between osteocytic and anosteocytic bone material
N2 - Vertebrate bones are made of a nanocomposite consisting of water, mineral and organics. Water helps bone material withstand mechanical stress and participates in sensation of external loads. Water diffusion across vertebrae of medaka (bone material lacking osteocytes) and zebrafish (bone material containing osteocytes) was compared using neutron tomography. Samples were measured both wet and following immersion in deuterated-water (D2O). By quantifying H+ exchange and mutual alignment with X-ray lCT scans, the amount of water expelled from complete vertebra was determined. The findings revealed that anosteocytic bone material is almost twice as amenable to D2O diffusion and H2O exchange, and that unexpectedly, far more water is retained in osteocytic zebrafish bone. Diffusion in osteocytic bones (only 33 % – 39 % water expelled) is therefore restricted as compared to anosteocytic bone (~ 60 % of water expelled), presumably because water flow is confined to the lacunar-canalicular network (LCN) open-pore system. Histology and Raman spectroscopy showed that anosteocytic bone contains less proteoglycans than osteocytic bone. These findings identify a previously unknown functional difference between the two bone materials. Therefore, this study proposes that osteocytic bone retains water, aided by non-collagenous proteins, which contribute to its poroelastic mechano-transduction of water flow confined inside the LCN porosity.
KW - Bone porosity
KW - Anosteocytic bone
KW - Water permeability
KW - Neutron tomography
KW - Proteoglycans
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564563
DO - https://doi.org/10.1016/j.matdes.2022.111275
VL - 224
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-56456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tsamos, Athanasios
A1 - Evsevleev, Sergei
A1 - Fioresi, R.
A1 - Faglioni, F.
A1 - Bruno, Giovanni
T1 - Synthetic Data Generation for Automatic Segmentation of X-ray Computed Tomography Reconstructions of Complex Microstructures
N2 - The greatest challenge when using deep convolutional neural networks (DCNNs) for automatic segmentation of microstructural X-ray computed tomography (XCT) data is the acquisition of sufficient and relevant data to train the working network. Traditionally, these have been attained by manually annotating a few slices for 2D DCNNs. However, complex multiphase microstructures would presumably be better segmented with 3D networks. However, manual segmentation labeling for 3D problems is prohibitive. In this work, we introduce a method for generating synthetic XCT data for a challenging six-phase Al–Si alloy composite reinforced with ceramic fibers and particles. Moreover, we propose certain data augmentations (brightness, contrast, noise, and blur), a special in-house designed deep convolutional neural network (Triple UNet), and a multi-view forwarding strategy to promote generalized learning from synthetic data and therefore achieve successful segmentations. We obtain an overall Dice score of 0.77. Lastly, we prove the detrimental effects of artifacts in the XCT data on achieving accurate segmentations when synthetic data are employed for training the DCNNs. The methods presented in this work are applicable to other materials and imaging techniques as well. Successful segmentation coupled with neural networks trained with synthetic data will accelerate scientific output.
KW - Automatic segmentation
KW - 3D deep convolutional neural network (3D DCNN)
KW - Dice score
KW - Metal matrix composite (MMC)
KW - Modified U-Net architectures
KW - Multi-phase materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571243
DO - https://doi.org/10.3390/jimaging9020022
VL - 9
IS - 2
SP - 1
EP - 23
PB - MDPI
AN - OPUS4-57124
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Z.
A1 - Dong, K.
A1 - Mazzio, K. A.
A1 - Hilger, A.
A1 - Markötter, Henning
A1 - Wilde, F.
A1 - Heinemann, T.
A1 - Manke, I.
A1 - Adelhelm, P.
T1 - Phase transformation and microstructural evolution of CuS electrodes in solid-state batteries probed by in situ 3D X-ray tomography
N2 - Copper sulfide shows some unique physico-chemical properties that make it appealing as a cathode active material (CAM) for solid-state batteries (SSBs). The most peculiar feature of the electrode reaction is the reversible formation of μm-sized Cu crystals during cycling, despite its large theoretical volume change (75%). Here, the dynamic microstructural evolution of CuS cathodes in SSBs is studied using in situ synchrotron X-ray tomography. The formation of μm-sized Cu within the CAM particles can be clearly followed. This process is accompanied by crack formation that can be prevented by increasing the stack pressure from 26 to 40 MPa. Both the Cu inclusions and cracks show a preferential orientation perpendicular to the cell stack pressure, which can be a result of a z-oriented expansion of the CAM particles during lithiation. In addition, cycling leads to a z-oriented reversible displacement of the cathode
pellet, which is linked to the plating/stripping of the Li counter electrode. The pronounced structural changes cause pressure changes of up to 6 MPa within the cell, as determined by operando stack pressure measurements. Reasons for the reversibility of the electrode reaction are discussed and are attributed to the favorable combination of soft materials.
KW - Copper sulfide
KW - Crack evolution
KW - Digital volume correlation
KW - Phase transformation
KW - Solid-state batteries
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564577
DO - https://doi.org/10.1002/aenm.202203143
IS - 2203143
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-56457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Van Tran, K.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Abou-Ras, D.
A1 - Puplampu, S.
A1 - Förster, C.
A1 - Penumadu, D.
A1 - Dahlberg, C. F. O.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography
N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale.
KW - Neutron tomography
KW - Phase distribution
KW - Rectangular cross-section
KW - Torsion
KW - Geometrical effect
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561649
DO - https://doi.org/10.1016/j.matdes.2022.111037
SN - 0264-1275
VL - 222
SP - 111037
PB - Elsevier Ltd.
AN - OPUS4-56164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tran, K. V.
A1 - Woracek, R.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Abou-Ras, D.
A1 - Puplampu, S.
A1 - Förster, C.
A1 - Penumadu, D.
A1 - Dahlberg, C. F. O.
A1 - Banhart, J.
A1 - Manke, I.
T1 - Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography
N2 - Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale.
KW - Neutron tomography
KW - Phase distribution
KW - Rectangular cross-section
KW - Torsion
KW - Geometrical effect
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569101
DO - https://doi.org/10.1016/j.matdes.2022.111037
VL - 222
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-56910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pacheco, V.
A1 - Marattukalam, J. J.
A1 - Karlsson, D.
A1 - Dessieux, L.
A1 - Tran, K. V.
A1 - Beran, P.
A1 - Manke, I.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Sahlberg, M.
A1 - Woracek, R.
T1 - On the relationship between laser scan strategy, texture variations and hidden nucleation sites for failure in laser powder-bed fusion
N2 - While laser powder-bed fusion has overcome some of the design constraints of conventional manufacturing methods, it requires careful selection of process parameters and scan strategies to obtain favorable properties. Here we show that even simple scan strategies, complex ones being inevitable when printing intricate designs, can inadvertently produce local alterations of the microstructure and preferential grain orientation over small areas – which easily remain unnoticed across the macroscale. We describe how a combined usage of neutron imaging and electron backscatter diffraction can reveal these localized variations and explain their origin within cm-sized parts. We explain the observed contrast variations by linking the neutron images to simulated data, pole figures and EBSD, providing an invaluable reference for future studies and showing that presumably minor changes of the scan strategy can have detrimental effects on the mechanical properties. In-situ tensile tests reveal that fracture occurs in a region that was re-melted during the building process.
KW - Laser powder-bed fusion
KW - Texture
KW - Preferential orientation
KW - Diffraction contrast neutron imaging
KW - Bragg-edge
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568054
DO - https://doi.org/10.1016/j.mtla.2022.101614
VL - 26
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-56805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, T.
A1 - Kalinka, Gerhard
A1 - Mieller, Björn
T1 - Manufacturing and deformation behavior of alumina and zirconia helical springs at room temperature
N2 - Ceramic helical springs with identical dimensions were produced by hard machining from alumina, alumina toughened zirconia (ATZ), and tetragonal zirconia polycrystals (TZP) stabilized with different oxides. According to the results of the spring constant determination under deformation rates of 3 mm/min, the deformation behavior of all ceramic springs obeys to Hook’s law. However, variation of the deformation rate, tests under constant load, and spring recovery behavior revealed differences in the deformation behavior of alumina, TZP, and ATZ springs. Alumina springs exhibited time-independent deformation in all tests. In contrast, anelastic deformation at room temperature was demonstrated in all springs containing TZP. This deformation is completely reversible over a period of several days. Anelastic behavior is particularly pronounced in Y-TZP springs, whereas Ce-TZP springs exhibit comparatively very low but still reliably detectable anelasticity. Oxygen vacancies in the TZP ceramic are considered the most likely explanation for the anelastic behavior of TZP springs at room temperature.
KW - Alumina
KW - Creep
KW - Elastic properties
KW - Zirconia
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571858
DO - https://doi.org/10.1111/jace.19085
SN - 0002-7820
SP - 1
EP - 14
PB - Wiley-Blackwell
CY - Oxford [u.a.]
AN - OPUS4-57185
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lapenna, Michela
A1 - Faglioni, Francesco
A1 - Chand, Keerthana
A1 - Hejazi, Bardia
A1 - Fioresi, Rita
A1 - Bruno, Giovanni
T1 - Chamfer distance for non-linear registration of Triply Periodic Minimal Surface lattices
N2 - We present a 3D image registration technique for non-linear deformation estimation in Additive Manufacturing processes. The methodology involves comparing X-ray Computed Tomography (XCT) data with Computer Aided Design (CAD) models for Triply Periodic Minimal Surface (TPMS) lattices and employs the Chamfer distance to refine mesh non-linear deformations.
KW - X-ray Computed tomography
KW - Defects
KW - Machine Learning
KW - Digital Twin
KW - Registration
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637367
DO - https://doi.org/10.1016/j.addlet.2025.100299
SN - 2772-3690
VL - 14
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bouabadi, Bouchra
A1 - Hilger, André
A1 - Kamm, Paul H.
A1 - Neu, Tillmann R.
A1 - Kardjilov, Nikolay
A1 - Sintschuk, Michael
A1 - Markötter, Henning
A1 - Schedel‐Niedrig, Thomas
A1 - Abou‐Ras, Daniel
A1 - García‐Moreno, Francisco
A1 - Risse, Sebastian
T1 - Morphological Evolution of Sn‐Metal‐Based Anodes for Lithium‐Ion Batteries Using Operando X‐Ray Imaging
N2 - Sn‐based electrodes are promising candidates for next‐generation lithium‐ion batteries. However, it suffers from deleterious micro‐structural deformation as it undergoes drastic volume changes upon lithium insertion and extraction. Progress in designing these materials is limited to complex structures. There is a significant need to develop an alloy‐based anode that can be industrially manufactured and offers high reversible capacity. This necessitates a profound understanding of the interplay between structural changes and electrochemical performance. Here, operando X‐ray imaging is used to correlate the morphological evolution to electrochemical performance in foil and foam systems. The 3D Sn‐foam‐like structure electrode is fabricated in‐house as a practical approach to accommodate the volume expansion and alleviate the mechanical stress experienced upon alloying/dealloying. Results show that generating pores in Sn electrodes can help manage the volume expansion and mitigate the severe mechanical stress in thick electrodes during alloying/dealloying processes. The foam electrode demonstrates superior electrochemical performance compared to non‐porous Sn foil with an equivalent absolute capacity. This work advances the understanding of the real‐time morphological evolution of Sn bulky electrodes.
KW - Synchrotron radiation
KW - X-ray imaging
KW - Lithium-ion battery
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640112
DO - https://doi.org/10.1002/advs.202414892
SN - 2198-3844
VL - 12
IS - 10
SP - 1
EP - 10
PB - Wiley
AN - OPUS4-64011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rieder, Philipp
A1 - Petrich, Lukas
A1 - Serrano-Munoz, Itziar
A1 - Mouiya, Mossaab
A1 - Markötter, Henning
A1 - Huger, Marc
A1 - Bruno, Giovanni
A1 - Schmidt, Volker
T1 - Statistical analysis of grains and pores within polycrystalline Al2TiO5 ceramics, based on X-ray computed tomography
N2 - Advanced statistical image analysis workflows were developed to segment and quantitatively evaluate 2D electron-backscatter diffraction (EBSD) maps and 3D synchrotron X-ray computed tomography (SXCT) volumes of a polycrystalline Al2TiO5 refractory composite that contains microcracks and pores. Several size, shape, and further geometric descriptors were determined for both the solid phase (Al2TiO5 grains) and the pore space. The resulting pore-size distribution is distinctly bimodal: coarse pores (tens to hundreds of micrometers), traced to incomplete powder compaction, coexist with fine pores generated during sintering. The two pore populations appear to be correlated with grain growth and crystallographic orientation in different ways. Finally, the descriptors obtained from the 2D EBSD and 3D SXCT data sets are internally consistent but complementary, highlighting the value of characterizations based on EBSD and SXCT in the microstructural study of refractory ceramics.
KW - Synchrotron X-ray computed tomography
KW - Electron-backscatter diffraction
KW - Aluminum titanate
KW - Morphological reconstruction
KW - Image Segmentation
KW - Statistical image analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643918
DO - https://doi.org/10.1016/j.matchar.2025.115602
SN - 1044-5803
VL - 229
SP - 1
EP - 13
PB - Elsevier Inc.
AN - OPUS4-64391
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruson, Danilo
A1 - Serrano-Munoz, Itziar
A1 - Fritsch, Tobias
A1 - Markötter, Henning
A1 - Galati, Manuela
T1 - Revealing the (positive) role of porosity within polymeric additively manufactured lattices via X-ray computed tomography
N2 - The mechanical properties of lattice geometries are known to be significantly influenced by a variety of manufacturing defects. This study investigates the influence of porosity on the mechanical behaviour of strut-based body-centred cubic (BCC) lattice structures produced with powder bed fusion with laser beam PBF-LB/P using PA2200 nylon powder. The study combines advanced techniques, including in-situ laboratory X-ray computed tomography (XCT), synchrotron XCT to visualise pores and roughness in high resolution at a single-cell level and image-based finite element analysis (FEA). The findings show that failure in thin-walled AM lattices is governed by the combined effects of porosity morphology, location, surface roughness, and cross-section reduction. The presence of internal porosity is found to attenuate both the amplitude of elastic modulus fluctuations and the severity of stress concentrations induced by surface irregularities.
KW - Nylon Pa2200
KW - Laser powder bed fusion (PBF-LB)
KW - Processing defects
KW - Synchrotron X-ray computed tomography (XCT)
KW - Digital volume correlation (DVC)
KW - Image-based finite element simulations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633245
DO - https://doi.org/10.1016/j.ijsolstr.2025.113488
SN - 0020-7683
VL - 320
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-63324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buljak, Vladimir
A1 - Serrano-Munoz, Itziar
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Prasek, Marko
A1 - Contillo, Adriano
A1 - Mouiya, Mossaab
A1 - Huger, Marc
A1 - Bruno, Giovanni
T1 - On the closure of thermally induced micro-cracks in aluminum titanate ceramics
N2 - Aluminum Titanate (AT) refractory ceramics (as some other ceramic composites) are prone to microcracking, due to the thermal expansion anisotropy of AT and to the mismatch with the thermal expansion of the constituents. Such microcracks cause the room temperature Young's modulus to be only a fraction of that of the non-microcracked material. As a function of temperature, the Young's modulus increases non-linearly. Such increase suggests that microcracks close or even heal at high temperatures. Upon cooling, thermal stress accumulates again, and microcracks re-open. This cycle is fully reversible. While confirming the hysteretic behavior of the Young's modulus, we observe that the amount of microcracks (as determined by in-situ Synchrotron X-ray refraction radiography) decreases linearly upon heating. The apparent mismatch between the Young's modulus and the microcrack content dependence on temperature is explained by a simple FEM model. Such model employs cohesive elements upon cooling, in order to estimate the amount of initial microcracks. On purpose, the model does not include healing upon heating and only allows crack closure. It predicts that crack closure continuously occurs upon heating, thereby qualitatively reproducing the nearly linear dependence of the X-ray refraction signal. It is therefore concluded that the sudden and non-linear increase of Young's modulus with temperature is mainly caused by crack healing. Such finding agrees with previous work and paves the road to a more systematic separation of crack closure and healing in flexible ceramics.
KW - X-ray computed tomography
KW - X-ray refraction radiography
KW - In-situ imaging
KW - BAMline
KW - Micromechanics
KW - BESSY II
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645082
DO - https://doi.org/10.1016/j.ceramint.2025.09.237
SN - 0272-8842
VL - 51
IS - 27
SP - 55141
EP - 55152
PB - Elsevier
CY - Amsterdam
AN - OPUS4-64508
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
A1 - Lapenna, M.
A1 - Faglioni, F.
A1 - Fioresi, R.
T1 - Temperature-based pruning for input features in Graph Neural Networks
N2 - In the presentwork,we employ the concept of neural network temperature to prune unimportant features in input to aGraph Neural Network (GNN) architecture. In benchmark datasets for node and graph property prediction, each node comes equipped with a vector of numerous features. It is paramount to understand which information is actually necessary and which can be discarded, both for efficiency and explainability. The temperature is linked to the gradient activity due to the loss function minimization and leads to pruning of weight structures associated with small gradients. This study is done on different GNN architectures, one for node classification and another one for link prediction, and several benchmark datasets are employed.We compare the results with similar experiments previously conducted on the filters of Convolutional Neural Networks. Although still at the proof-of-concept stage, our temperature-based pruning technique stands as a promising alternative to state-of-the-art magnitude-based pruning techniques.
KW - Temperature-based pruning
KW - Graph Neural Networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640886
VL - 140
SP - 1
EP - 20
PB - Springer
AN - OPUS4-64088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gunnerek, R.
A1 - Soundarapandiyan, G.
A1 - Mishurova, T.
A1 - Schröder, J.
A1 - Bruno, Giovanni
A1 - Boykin, J.
A1 - Diaz, A.
A1 - Klement, U.
A1 - Hryha, E.ON
T1 - Chemical mechanical polishing of powder bed fusion – laser beam processed 316 L stainless steel
N2 - Additive manufacturing via powder bed fusion – laser beam (PBF-LB) enables the fabrication of complex geometries but suffers from inherently rough surfaces and surface tensile residual stresses, both of which can compromise structural integrity, particularly under fatigue loading. To address these limitations, this study investigates chemical mechanical polishing (CMP) as a surface finishing method for improving surface quality and modifying the residual stress state in PBF-LB 316 L stainless steel. The work uniquely examines how scan rotation (0◦ vs. 67◦ rotation) and contour parameters influence CMP effectiveness in material removal, surface smoothing, and subsurface stress redistribution. With a targeted material removal of 110 μm, CMP reduced surface roughness (Sa) by up to 94 %, achieving values as low as 0.7 μm. Microstructural analysis revealed no grain refinement but identified a thin, plastically deformed surface layer. This plastic deformation resulted in the transformation of tensile surface stresses (340 MPa) into beneficial compressive stresses ( 400 MPa), as confirmed by synchrotron X-ray diffraction, which also showed a shift toward isotropic strain distribution. Further, these findings demonstrate that the initial scan strategy influences CMP performance and that CMP can enhance both surface integrity and mechanical reliability without altering the underlying microstructure. This study advances the understanding of how process induced microstructure and surface features affect CMP outcomes, enabling more informed design of post-processing strategies for improved surface integrity and mechanical performance in additively manufactured metals.
KW - Residual stress
KW - Additive manufacturing
KW - Chemical mechanical polishing
KW - As-built microstructure
KW - Surface roughness
KW - Surface finishing
KW - Material removal
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640522
DO - https://doi.org/10.1016/j.jmatprotec.2025.119055
SN - 0924-0136/
VL - 345
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-64052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Hejazi, Bardia
A1 - Chand, Keerthana
A1 - Fritsch, Tobias
A1 - Bruno, Giovanni
T1 - D-CNN and VQ-VAE Autoencoders for Compression and Denoising of Industrial X-Ray Computed Tomography Images
N2 - The ever-growing volume of data in imaging sciences stemming from advancements in imaging technologies, necessitates efficient and reliable storage solutions for such large datasets. This study investigates the compression of industrial X-ray computed tomography (XCT) data using deep learning autoencoders and examines how these compression algorithms affect the quality of the recovered data. Two network architectures with different compression rates were used, a deep convolution neural network (D-CNN) and a vector quantized variational autoencoder (VQ-VAE). The XCT data used was from a sandstone sample with a complex internal pore network as a good test case for the importance of feature preservation. The quality of the decoded images obtained from the two different deep learning architectures with different compression rates were quantified and compared to the original input data. In addition, to improve image decoding quality metrics, we introduced a metric sensitive to edge preservation, which is crucial for three-dimensional data analysis. We showed that different architectures and compression rates are required depending on the specific characteristics needed to be preserved for later analysis. The findings presented here can aid scientists in determining the requirements and strategies needed for appropriate data storage and analysis.
T2 - 28th European Conference on Artificial Intelligence – Including 14th Conference on Prestigious Applications of Intelligent Systems (PAIS 2025)
CY - Bologna, Italy
DA - 25.10.2025
KW - Data Compression
KW - Deep Learning
KW - X-ray Computed Tomography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644758
UR - https://ebooks.iospress.nl/doi/10.3233/FAIA251480
DO - https://doi.org/10.3233/FAIA251480
SN - 0922-6389
SP - 1
EP - 8
PB - IOS Press
AN - OPUS4-64475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfaff, Jonas
A1 - Schopferer, Sebastian
A1 - Markötter, Henning
A1 - Rack, Alexander
A1 - Bruno, Giovanni
A1 - Schmidt, Anita
A1 - Tichter, Tim
A1 - Böttcher, Nils
T1 - High-speed synchrotron radiography of nail penetration-induced thermal runaway: Understanding the explosive behavior of commercial sodium-ion batteries with NFM cathode
N2 - The dynamics of mechanically initiated thermal runaway (TR) events in cylindrical 18650 cells with NFM (Na(Ni1/3Fe1/3Mn1/3)O2), LFP (LiFePO4), and NMC532 (LiNi1/2Mn1/3Co1/5O2) cathode chemistries were investigated using high-speed synchrotron X-ray imaging. Structural similarity index measures (SSIM) were employed to identify and track rapid structural changes. In this manner, thermal decompositions and internal propagation dynamics, influencing the safety mechanisms of the cells, were studied. This lead to two major findings: (I) Among NFM, LFP, and NMC532 cells, the TR-characteristics differ significantly in temperature and internal propagation speed. Internal safety mechanisms appear, however, visually similar. Among all samples, LFP cells exhibit higher safety performance concerning the initiation of TR by nail penetration and the progression of TR. (II) The NFM cells used in this study displayed an almost explosive TR. This finding appears counterintuitive on a first glance, since sodium-ion batteries are usually considered safe. High-speed imaging revealed that the explosive TR is not necessarily caused by the thermochemical decomposition reactions, but rather by a failure of the venting mechanism. This results in a significant pressure buildup within the cell upon TR initiation and eventually a severely violent TR. These results underline that battery safety depends on many factors and not solely on optimized cell chemistries or materials.
KW - High-speed X-ray radiography
KW - Synchrotron X-rays
KW - 18650
KW - SIB
KW - Na-NFM
KW - Structure similarity index measure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642649
DO - https://doi.org/10.1016/j.powera.2025.100188
SN - 2666-2485
VL - 36
SP - 1
EP - 7
PB - Elsevier Ltd.
AN - OPUS4-64264
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
ED - Bruno, Giovanni
T1 - Micro Non-Destructive Testing and Evaluation
N2 - What is meant by ‘Micro Non-Destructive Testing and Evaluation’? This was the central subject of debate in this Special Issue.
At present, sub-millimeter-size components or even assemblies are pervading the industrial and scientific world. Classic examples are electronic devices and watches (as well as parts thereof), but recent examples encompass additively manufactured lattice structures, stents, or other microparts. Moreover, most assemblies contain micro-components. Testing such components or their miniaturized parts would fit well within the topic of micro non-destructive testing and evaluation.
In all cases, performance and integrity testing, quality control, and dimensional tolerances need to be measured at the sub-millimeter level (ideally with a spatial resolution of about a micron); most of the time, such features and components are embedded in much larger assemblies, which also need to be taken into account. The solution to this dilemma (i.e. measuring large parts with high resolution) depends on the part and on the problem under consideration.
Another possible definition of micro non-destructive testing and evaluation can relate to the characterization of micro-features (e.g., the microstructure) in much larger specimens, such as damage in concrete cores or porosity in additively manufactured components. A further aspect is the use of microscopic probes to evaluate macroscopic properties. This is the case, for instance but not at all exclusively, in the use of diffraction techniques to determine macroscopic stress.
The splits between testing and characterization at the micro-level (or of micro parts) from one side and handling of macroscopic assemblies on the other represent a great challenge for many fields of materials characterization. On top of that, including the use of microscopic methods to test integrity would add a further level of complexity.
Imaging, mechanical testing, non-destructive testing, measurement of properties, structural health monitoring, and dimensional metrology all need to be re-defined if we want to cope with the multi-faceted topic of micro non-destructive testing and evaluation.
The challenge has already been accepted by the scientific and engineering communities for a while but is still far from being universally tackled. This Special Issue yields an interesting answer to the questions posed above. It presents the progress made and the different aspects of the challenge as well as at indicates the paths for the future of NDT&E.
KW - Neutron Diffraction
KW - Ultrasound
KW - Eddy Currents
KW - X-ray Computed Tomography
KW - Mechanical Properties
KW - Residual Stress
KW - Defects
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570321
SN - 978-3-0365-6180-6
DO - https://doi.org/10.3390/books978-3-0365-6180-6
SN - 1996-1944
SP - 1
EP - 304
PB - MDPI
CY - Basel
AN - OPUS4-57032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hejazi, Bardia
A1 - Compart, Amaya
A1 - Fritsch, Tobias
A1 - Wagner, Ruben
A1 - Weidner, Anja
A1 - Biermann, Horst
A1 - Benz, Christopher
A1 - Sander, Manuela
A1 - Bruno, Giovanni
T1 - Fatigue Crack Segmentation and Characterization of Additively Manufactured Ti‐6Al‐4V Using X‐Ray Computed Tomography
N2 - X‐ray computed tomography (XCT) is extremely useful for the non‐destructive analysis of additively manufactured (AM) components. AM components often show manufacturing defects such as lack‐of‐fusion (LoF), which are detrimental to the fatigue life of components. To better understand how cracks initiate and propagate from internal defects, we fabricated Ti‐6Al‐4V samples with an internal cavity using electron beam powder bed fusion. The samples were tested in high‐cycle and very high‐cycle fatigue regimes. XCT was used to locate crack initiation sites and to determine characteristic properties of cracks and defects with the aid of deep learning segmentation. LoF defects exposed to the outer surface of the samples after machining were found to be as detrimental to fatigue life as the internal artificial defects. This work can benefit industries that utilize the AM of high‐strength, lightweight alloys, in the design and manufacturing of components to improve part reliability and fatigue life.
KW - Additive manufacturing
KW - Deep learning
KW - Ttitanium alloy
KW - Very high-cycle fatigue
KW - X-ray computed tomography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615107
DO - https://doi.org/10.1111/ffe.14489
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-61510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eddah, Mustapha
A1 - Markötter, Henning
A1 - Mieller, Björn
A1 - Sintschuk, Michael
A1 - Beckmann, Jörg
A1 - Bruno, Giovanni
T1 - Mitigation of DMM-induced stripe patterns in synchrotron X-ray radiography through dynamic tilting
N2 - In synchrotron X-ray radiography, achieving high image resolution and an optimal signal-to-noise ratio (SNR) is crucial for the subsequent accurate image analysis. Traditional methods often struggle to balance these two parameters, especially in situ applications where rapid data acquisition is essential to capture specific dynamic processes. For quantitative image data analysis, using monochromatic X-rays is essential. A double multilayer monochromator (DMM) is successfully used for this aim at the BAMline, BESSY II (Helmholtz Zentrum Berlin, Germany). However, such DMMs are prone to producing an unstable horizontal stripe pattern. Such an unstable pattern renders proper signal normalization difficult and thereby causes a reduction of the SNR. We introduce a novel approach to enhance SNR while preserving resolution: dynamic tilting of the DMM. By adjusting the orientation of the DMM during the acquisition of radiographic projections, we optimize the X-ray imaging quality, thereby enhancing the SNR. The corresponding shift of the projection during this movement is corrected in post-processing. The latter correction allows a good resolution to be preserved. This dynamic tilting technique enables the homogenization of the beam profile and thereby effectively reduces noise while maintaining high resolution. We demonstrate that data captured using this proposed technique can be seamlessly integrated into the existing radiographic data workflow, as it does not need hardware modifications to classical X-ray imaging beamline setups. This facilitates further image analysis and processing using established methods.
KW - Double multilayer monochromators
KW - Synchrotron X-ray imaging
KW - Signal normalization
KW - BAMline
KW - Dynamic tilting
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615049
DO - https://doi.org/10.1107/S1600577524008646
SN - 1600-5775
VL - 31
SP - 1551
EP - 1560
PB - International Union of Crystallography (IUCr)
AN - OPUS4-61504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voloskov, Boris
A1 - Mishurova, Tatiana
A1 - Evlashin, Stanislav
A1 - Firsov, Denis
A1 - Bruno, Giovanni
A1 - Sergeichev, Ivan
T1 - Influence of scanning strategy and hatch distance on porosity and mechanical characteristics of 316L stainless steel produced by laser powder bed fusion
N2 - The effect of scanning strategies and hatch distances on the porosity and mechanical properties of 316L stainless steel produced by laser powder bed fusion (PBF-LB) is studied. Two scanning strategies were analyzed along with three hatch distances (50 μm, 80 μm, and 110 μm). Using X-ray computed tomography (XCT), the study revealed different defect distributions: 90° alternating hatch scanning strategy resulted in a higher number of lack of fusion defects, while the chessboard strategy produced smaller, more uniformly distributed gas pores. The optimal hatch distance of 80 μm was found to minimize porosity and maximize tensile strength for both strategies. Mechanical testing supported these findings, showing that specimens printed with an 80 μm hatch distance exhibited better mechanical characteristics. This study highlights the critical role of scanning parameters in the quality
and reliability of additively manufactured parts.
KW - X-ray computed tomography
KW - Additive manufacturing
KW - Porosity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621164
DO - https://doi.org/10.1016/j.prostr.2024.11.045
SN - 2452-3216
VL - 65
SP - 302
EP - 309
PB - Elsevier B.V.
AN - OPUS4-62116
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duewer, D. L.
A1 - Sander, L. C.
A1 - Wise, S. A.
A1 - Philipp, Rosemarie
A1 - Hein, Sebastian
A1 - Hackenberg, R.
A1 - Polzer, J.
A1 - Avila, M. A.
A1 - Serrano, V.
A1 - Kakoulides, E.
A1 - Alexopoulos, C.
A1 - Giannikopoulou, P.
A1 - Chan, P.
A1 - Lee, H.
A1 - Tang, H.
A1 - Tang, P.
A1 - Yip, Y.
A1 - Lu, T.
A1 - Cheow, P. S.
A1 - Teo, T. L.
A1 - Sega, M.
A1 - Rolle, F.
A1 - Baek, S.
A1 - Kim, B.
A1 - Lee, S.
A1 - Cabillic, J.
A1 - Fallot, C.
A1 - Hua, T.
A1 - Dazhou, C.
A1 - Changjun, Y.
A1 - Chunxin, L.
A1 - Hongmei, L.
A1 - Lippa, K.
A1 - Itoh, N.
A1 - Quinn, L.
A1 - Prevoo-Franzsen, D.
A1 - Fernandes-Whaley, M.
A1 - Gören, A. C.
A1 - Gökcen, T.
A1 - Gündüz, S.
A1 - Krylov, A.
A1 - Mikheeva, A.
A1 - Baldan, A.
A1 - van der Hout, J. W.
A1 - van der Veen, A. M. H.
T1 - CCQM-K131 Low-polarity analytes in a multicomponent organic solution: Polycyclic aromatic hydrocarbons (PAHs) in acetonitrile
N2 - Solutions of organic analytes of known mass fraction are typically used to calibrate the measurement processes used to determine these compounds in matrix samples. Appropriate value assignments and uncertainty calculations for calibration solutions are critical for accurate measurements. Evidence of successful participation in formal, relevant international comparisons is needed to document measurement capability claims (CMCs) made by national metrology institutes (NMIs) and designated institutes (DIs). To enable NMIs and DIs to update or establish their claims, in 2015 the Organic Analysis Working Group (OAWG) sponsored CCQM-K131 "Low-Polarity Analytes in a Multicomponent Organic Solution: Polycyclic Aromatic Hydrocarbons (PAHs) in Acetonitrile".
Polycyclic aromatic hydrocarbons (PAHs) result from combustion sources and are ubiquitous in environmental samples. The PAH congeners, benz[a]anthracene (BaA), benzo[a]pyrene (BaP), and naphthalene (Nap) were selected as the target analytes for CCQM-K131. These targets span the volatility range of PAHs found in environmental samples and include potentially problematic chromatographic separations. Nineteen NMIs participated in CCQM-K131. The consensus summary mass fractions for the three PAHs are in the range of (5 to 25) μg/g with relative standard deviations of (2.5 to 3.5) %.
Successful participation in CCQM-K131 demonstrates the following measurement capabilities in determining mass fraction of organic compounds of moderate to insignificant volatility, molar mass of 100 g/mol up to 500 g/mol, and polarity pKow < −2 in a multicomponent organic solution ranging in mass fraction from 100 ng/g to 100 μg/g: (1) value assignment of primary reference standards (if in-house purity assessment carried out), (2) value assignment of single and/or multi-component organic solutions, and (3) separation and quantification using gas chromatography or liquid chromatography.
KW - Benz[a]anthracene (BaA)
KW - Benzo[a]pyrene (BaP)
KW - Gas chromatography (GC)
KW - Isotope dilution (ID)
KW - Liquid chromatography (LC)
KW - Mass spectrometry (MS)
KW - Naphthalene (Nap)
KW - Organic calibration solution
KW - Polycyclic aromatic hydrocarbon (PAH)
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471442
DO - https://doi.org/10.1088/0026-1394/56/1A/08003
SN - 0026-1394
SN - 1681-7575
VL - 56
IS - 1A
SP - 08003, 1
EP - 102
PB - IOP Science
AN - OPUS4-47144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bassil, A.
A1 - Wang, Xin
A1 - Chapeleau, X.
A1 - Niederleithinger, Ernst
A1 - Abraham, O.
A1 - Leduc, D.
T1 - Distributed fiber optics sensing and coda wave interferometry techniques for damage monitoring in concrete structures
N2 - The assessment of Coda Wave Interferometry (CWI) and Distributed Fiber Optics Sensing (DFOS) techniques for the detection of damages in a laboratory size reinforced concrete beam is presented in this paper. The sensitivity of these two novel techniques to micro cracks is discussed and compared to standard traditional sensors. Moreover, the capacity of a DFOS technique to localize cracks and quantify crack openings is also assessed. The results show that the implementation of CWI and DFOS techniques allow the detection of early subtle changes in reinforced concrete structures until crack formation. With their ability to quantify the crack opening, following early detection and localization, DFOS techniques can achieve more effective monitoring of reinforced concrete structures. Contrary to discrete sensors, CWI and DFOS techniques cover larger areas and thus provide more efficient infrastructures asset management and maintenance operations throughout the lifetime of the structure.
KW - Distributed fiber optic sensors
KW - Coda wave interferometry
KW - Reinforced concrete
KW - Cracks
KW - Damage detection
KW - Structural health monitoring
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472549
DO - https://doi.org/10.3390/s19020356
SN - 1424-8220
VL - 19
IS - 2
SP - 356, 1
EP - 15
PB - MDPI
AN - OPUS4-47254
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Khatib, A. H.
A1 - Radbruch, H.
A1 - Trog, S.
A1 - Neumann, B.
A1 - Paul, F.
A1 - Koch, A.
A1 - Linscheid, M. W.
A1 - Jakubowski, Norbert
A1 - Schellenberger, E.
T1 - Gadolinium in human brain sections and colocalization with other elements
N2 - Recent recommendations by the Food and Drug Administration1 and the European Medicines Agency2 are to limit the clinical use of linear gadolinium-based contrast agents (GBCAs) due to convincing evidence of deposition in tissues. Macrocyclic GBCA continued to be considered safe, provided that patients have normal renal function. To date, given the low sensitivity of conventional MRI, there has been a debate about the signal increase following the injections of a macrocyclic GBCA.
KW - Gadolinium
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471309
DO - https://doi.org/10.1212/NXI.0000000000000515
SN - 2332-7812
VL - 6
IS - 1
SP - e515, 1
EP - 3
PB - American Academy of Neurology
AN - OPUS4-47130
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heck, Christian
A1 - Kanehira, Y.
A1 - Kneipp, Janina
A1 - Bald, Ilko
T1 - Amorphous Carbon Generation as a Photocatalytic Reaction on DNA-Assembled Gold and Silver Nanostructures
N2 - Background signals from in situ-formed amorphous carbon, despite not being fully understood, are known to be a common issue in few-molecule surface-enhanced Raman scattering (SERS). Here, discrete gold and silver nanoparticle aggregates assembled by DNA origami were used to study the conditions for the formation of amorphous carbon during SERS measurements. Gold and silver dimers were exposed to laser light of varied power densities and wavelengths. Amorphous carbon prevalently formed on silver aggregates and at high power densities. Time-resolved measurements enabled us to follow the formation of amorphous carbon. Silver nanolenses consisting of three differently-sized silver nanoparticles were used to follow the generation of amorphous carbon at the single-nanostructure level. This allowed observation of the many sharp peaks that constitute the broad amorphous carbon signal found in ensemble measurements. In conclusion, we highlight strategies to prevent amorphous carbon formation, especially for DNA-assembled SERS substrates.
KW - Amorphous carbon
KW - DNA origami
KW - SERS
KW - Nanoparticle dimers
KW - Nanolenses
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486484
DO - https://doi.org/10.3390/molecules24122324
SN - 1420-3049
VL - 24
IS - 12
SP - Article Number: 2324-1
EP - 10
PB - MDPI
AN - OPUS4-48648
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schürmann, Robin
A1 - Ebel, Kenny
A1 - Nicolas, C.
A1 - Milosavljevic, A. R.
A1 - Bald, Ilko
T1 - Role of valence band states and plasmonic enhancement in electron-transfer-induced transformation of nitrothiophenol
N2 - Hot-electron-induced reactions are more and more recognized as a critical and ubiquitous reaction in heterogeneous catalysis. However, the kinetics of these reactions is still poorly understood, which is also due to the complexity of plasmonic nanostructures. We determined the reaction rates of the hot-electron-mediated reaction of 4-nitrothiophenol (NTP) on gold nanoparticles (AuNPs) using fractal kinetics as a function of the laser wavelength and compared them with the plasmonic enhancement of the system. The reaction rates can be only partially explained by the plasmonic response of the NPs. Hence, synchrotron X-ray photoelectron spectroscopy (XPS) measurements of isolated NTP-capped AuNP clusters have been performed for the first time. In this way, it was possible to determine the work function and the accessible valence band states of the NP systems. The results show that besides the plasmonic enhancement, the reaction rates are strongly influenced by the local density of the available electronic states of the system.
KW - Photocatalytic reduction
KW - Raman-spectroscopy
KW - Hot-electrons
KW - Work function
KW - Surface
KW - Nanaoparticles
KW - Scattering
KW - Molecule
KW - Carriers
KW - Layers
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486464
DO - https://doi.org/10.1021/acs.jpclett.9b00848
SN - 1948-7185
VL - 10
IS - 11
SP - 3153
EP - 3158
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-48646
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Illemann, J.
A1 - Meinel, Dietmar
A1 - Bellon, Carsten
T1 - Effektive Bestimmung der Fokusparameter von Mikrofokus-Röntgenquellen
N2 - Mikrofokus-Röntgenquellen werden in der industriellen CT flexibelverwendet, um mit kleiner Leistung hohe Auflösung zu erzielen oder mit verminderter Auflösung bei höherer Leistung kürzere Messzeiten zu erreichen. Insbesondere Quellen in offener Bauweise benötigen Wartung wie Filamentwechsel und Nachstellen der Fokusparameter. Ziel ist es, einen optimal kleinen Quellfleck bei bekannter Spannung einzustellen und dessen Größe zu bestimmen.
Zur Überprüfung der Quellfleckgröße sind bereits Verfahren unter Verwendung lithographisch hergestellter Masken mit Strichmustern oder Siemenssternen aus Mikrometer dünnen Schichten aus stark absorbierendem Material wie z.B. Gold bekannt. Diese erfordern wegen der geringen Absorption eine lange Messzeit und sind nur kostenintensiv herzustellen. Ihre Verwendung zur regelmäßigen Qualitätsüberprüfung von CT-Anlagen ist daher nicht verbreitet.
Ziel dieser Arbeit ist es, die richtungsabhängige Quellfleckgröße absolut zu bestimmen, wobei nur einfach zu beschaffende Wolframspitzen verwendet werden. Dazu werden radiographische Bilder in hoher Vergrößerung aufgenommen und die Grauwertverteilung parametrisiert. Unter Verwendung der Kenntnis von Targetmaterial und Spannung wird eine eineindeutige Zuordnung zur Quellfleckgröße vorgenommen.
Dieses erfordert eine extensive Simulation für verschiedene Spannungen, Fokusgrößen und andere Einflussgrößen, sowie die experimentelle Verifikation an verschiedenen CT-Anlagen im Vergleich zu einer bekannten Methode. Erste Ergebnisse werden vorgestellt und die praktische Implementierung unter Angabe der Einschränkungen der Verwendbarkeit diskutiert. Die Autoren hoffen, damit einen wesentlichen Beitrag zur Verbesserung der Qualitätssicherung und zur
Arbeitseffizienz in der Mikrocomputertomographie leisten zu können.
T2 - DGZfP DACH-Jahrestagung 2019
CY - Friedrichshafen, Germany
DA - 27.05.2019
KW - Mikro-Computertomographie
KW - Röntgenröhre
KW - Quellfleckgröße
KW - Brennfleck
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485960
UR - https://www.ndt.net/search/docs.php3?id=24551
UR - https://www.ndt.net/article/dgzfp2019/papers/Mi.2.A.3.pdf
IS - NDT.net Issue: 2019-08
SP - 1
EP - 13
AN - OPUS4-48596
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nöller, Renate
A1 - Hahn, Oliver
A1 - Overgaauw, E.
A1 - Danielewski, A.
A1 - Giel, R.
T1 - Analyse von Humboldt Codices aus Mizquiahuala im Vergleich zu Fragmenten in Mexiko und Paris
N2 - Unter den von Humboldt in Amerika erworbenen Schriftstücken der Kolonialzeit findet sich eine Tributliste aus dem Jahr 1569, die der Otomí Bevölkerung aus dem Ort Mizquahuala im Staat Hidalgo/ Mexiko zugeordnet wird. Sie ist in Form eines Kalenders ausgeführt, Wochentage und verschiedene Produkte lassen sich unterscheiden. Eduard Seler beschreibt dieses Manuskript zusammen mit einer weiteren Tributliste, die in Inhalt und Zeichnung anders gestaltet ist, jedoch ebenfalls aus dieser Region stammt.
Mit den für die Analyse von Manuskripten bewährten Untersuchungsmethoden werden Papier und Farbmittel identifiziert. Hierzu zählen Raman-, FTIR-, Röntgenfluoreszenz- und VIS- Spektroskopie. Charakteristisch für die Herstellung von schriftlichen Dokumenten in der Kolonialzeit von Amerika ist die Verwendung von indigenem Material wie Papier aus Baumrinde und Pflanzenfarben zusammen mit den aus Europa bekannten Materialien. Geklärt wird, welche Auswahl von Farbstoffen zur Herstellung der Dokumente genutzt wurde, die diese als Gruppe klassifizieren könnte.
Die den beiden Fragmenten zugeordneten Farbmaterialien sowie formale und inhaltliche Aspekte lassen vermuten, dass zwei weitere Schriftstücke der Berliner Sammlung `Manuscripta Americana´, deren Herkunft nicht bekannt ist, mit ihnen in Beziehung gebracht werden können. Stilistisch gleiche Fragmente befinden sich zudem in Mexiko, Paris und den USA.
Im Vergleich dieser Fragmente untereinander wird diskutiert, inwieweit die über die Materialanalyse identifizierten spezifischen Farbstoffe einen Hinweis auf eine gemeinsame lokale Herkunft zulassen.
T2 - Jahrestagung Archäometrie und Denkmalpflege
CY - Wien, Austria
DA - 11.09.2019
KW - VIS- Spektroskopie
KW - Humboldt Codices
KW - RFA
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499192
SN - 0947-6229
VL - Sonderheft 9
SP - 186
EP - 189
CY - Bochum
AN - OPUS4-49919
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Osterloh, Kurt
A1 - Röhrs, S.
A1 - Schwabe, A.
A1 - Radujcovic, S.
A1 - Bücherl, T.
A1 - Dangendorf, V.
A1 - Zscherpel, Uwe
A1 - Reiche, I.
A1 - Nüsser, A.
ED - Zscherpel, Uwe
ED - Kasperl, S.
T1 - Elucidating the distribution of organic consolidants in wood by Neutron Tomography
N2 - While the absorption of X-rays and gamma radiation is determined by the Z-number of the elements a specimen is composed of, it is the hydrogen making an effective contrast with neutron imaging. As a consequence, interrogating with neutrons presents a suitable tool to study the distribution of organic consolidants in materials such as wood as encountered in impregnated wooden artworks.
Four different examples of objects are presented here to demonstrate the potential of neutron CT: 1) small wooden pieces of ship wrecks (< 2 cm thickness) interrogated with cold neutrons (0.5 meV at the ANTARES facility of the FRM II in Garching) to demonstrate the potential and the limitation of using low energy neutrons, 2) a wooden statue soaked with carbolineum (fission neutrons 1.8 MeV at the NECTAR facility of the FRM II), 3) a smaller wooden figure of a skull heavily soaked with carbolineum so it was too tight for the fission neutrons used before with accelerator neutrons (broad range about 5.5 MeV at the PTB in Braunschweig) and 4) pieces of charred wood to study the impregnation with a consolidant (NECTAR, FRM II). With the exception of the last example, all results have been combined with X-ray tomography (BAM 8.3 in Berlin). In the case of the charred wood specimens (example 4) the density histograms of the neutron tomography results were compared with those obtained from untreated references. The observed gain in specific density of the soaked specimens corresponded with an increase of specific weight. All results obtained so far showed distinct distribution patterns attributable to structural peculiarities or organic consolidants providing valuable support for subsequent restoration works.
T2 - International symposium on digital industrial radiography and computed tomography DIR2019
CY - Fürth, Germany
DA - 02.07.2019
KW - Neutron Imaging
KW - Cold to fast neutron testing
KW - Tomography of wood samples
KW - Art restauration
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505326
UR - https://www.ndt.net/search/docs.php3?id=24740
SN - 1435-4934
VL - 24
IS - 11
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-50532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zscherpel, Uwe
A1 - Ewert, Uwe
T1 - Aktuelle Entwicklungen in der Standardisierung
N2 - In den letzten zwei Jahren wurden 11 neue Standards/Standardrevisionen zur RT veröffentlicht (ohne Strahlenschutz) und 5 werden dafür gestrichen. Es wird über die neuen Anforderungen ausgewählter Normen bzw. Normrevisionen informiert und insbesondere auch über die veränderten Parameter, die bei Prüfpraxis und bei der Klassifizierung zu berücksichtigen sind. Das wichtigste Projekt ist die Revision der DIN EN ISO 17636-1, -2, RT von Schweißverbindungen, in ISO TC 44 SC 5 WG 1. Die Standards zur Schweißnahtprüfung in der Kerntechnik, DIN 25435, wurden ins Englische übertragen und bei ISO TC 85 SC 6 bearbeitet. Hauptaktivität bei ASTM ist gegenwärtig die Überarbeitung der CT-Standards und die Berücksichtigung der Anforderungen an das dimensionelle Messen. Der Guide ASTM E 1441 zur Bestimmung von MTF, Kontrast-Detail-Funktion (CDF) und Kontrast-Diskrimination-Diagramm (CDD) wird revidiert. E 2445 zur CR Long Term Stability wird ebenfalls revidiert. Die Revision soll auch in die ISO 16371-1 eingehen. Dazu ist ein Round Robin-Test geplant. Auch die Standards zur Durchstrahlungsprüfung auf Korrosion und Ablagerungen in Rohren mit Röntgen- und Gammastrahlen (EN 16407-1, -2, 2014) wurden revidiert. Diese Revision wurde als DIN EN ISO 20769-1, -2 2018 veröffentlicht und EN 16407 wird zurückgezogen. Die Revision der Standards EN 12543 und EN 12679 zur Messung der Brennfleckgröße und der Strahlergröße ist mit Verzögerung in Überarbeitung, um die digitalen Detektoren und Messmöglichkeiten mit Bildverarbeitungsprogrammen zu berücksichtigen. Ein Entwurf zur Messung der Brennfleckgröße von nano-Fokusröhren wird derzeit vom Europäischen Metrologie-Programm EMPIR gefördert. Zur radiographischen Gussteilprüfung wurde der Standard EN 12681 revidiert und 2018 veröffentlicht. Er wurde um Zulässigkeitsgrenzen erweitert und die digitale Radiographie wurde in Teil 2 berücksichtigt.
T2 - 17. Seminar der DGZfP "Aktuelle Fragen der Durchstrahlungsprüfung und des Strahlenschutzes"
CY - Kassel, Germany
DA - 28.03.2019
KW - Digitale Radiographie
KW - Standards
KW - Bildqualität
KW - Klassifizierung
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505371
UR - https://www.ndt.net/search/docs.php3?id=24807
VL - 24
IS - 12
SP - 1
EP - 5
PB - NDT.net
CY - Kirchwald
AN - OPUS4-50537
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Hahn, Oliver
ED - Corbach, A.
ED - Suchenwirth, R. H. R.
T1 - Arsen im Papier - Materialwissenschaftliche Untersuchungen von Bibliotheksgut
N2 - Materialwissenschaftliche Analysen werden an Bibliotheksgut durchgeführt, um kulturhistorische, restauratorische oder konservatorische Fragestellungen zu beantworten. Sie ermöglichen somit auch die Bestimmung von Art und Zusammensetzung arsenhaltiger Komponenten und erlauben Rückschlüsse darüber, ob diese durch Alterung und Korrosion freigesetzt werden können. Hier kann jedoch nur eine erste Einschätzung des Gefährdungspotenzials erfolgen; genaue Rückschlüsse auf die Konzentrationen in Raumluft oder Staub sind nur durch weiterführende Untersuchungen möglich. Es besteht ein Unterschied zwischen der Feststellung arsenhaltiger Substanzen in Bibliotheksgut und der Frage, ob diese auch tatsächlich freigesetzt werden. Dies wird am Beispiel der beiden Pigmente Smalte und Auripigment diskutiert.
KW - Bibliotheksgut
KW - Arsen
KW - Zerstörungsfreie Prüfung
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652376
SN - 978-3-447-12463-8
DO - https://doi.org/10.13173/WIF.6.037
VL - 6
SP - 37
EP - 45
PB - Harrassowitz
CY - Wiesbaden
AN - OPUS4-65237
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wohlleben, W.
A1 - Mielke, Johannes
A1 - Bianchin, A.
A1 - Ghanem, A.
A1 - Freiberger, H.
A1 - Rauscher, H.
A1 - Gemeinert, Marion
A1 - Hodoroaba, Vasile-Dan
T1 - Reliable nanomaterial classification of powders using the volume-specific surface area method
N2 - The volume-specific surface area (VSSA) of a particulate material is one of two apparently very different metrics recommended by the European Commission for a definition of "nanomaterial" for regulatory purposes: specifically, the VSSA metric may classify nanomaterials and non-nanomaterials differently than the median size in number metrics, depending on the chemical composition, size, polydispersity, shape, porosity, and aggregation of the particles in the powder.
Here we evaluate the extent of agreement between classification by electron microscopy (EM) and classification by VSSA on a large set of diverse particulate substances that represent all the anticipated challenges except mixtures of different substances. EM and VSSA are determined in multiple labs to assess also the level of reproducibility. Based on the results obtained on highly characterized benchmark materials from the
NanoDefine EU FP7 project, we derive a tiered screening strategy for the purpose of implementing the definition of nanomaterials. We finally apply the Screening strategy to further industrial materials, which were classified correctly and left only borderline cases for EM.
On platelet-shaped nanomaterials, VSSA is essential to prevent false-negative classification by EM. On porous materials, approaches involving extended Adsorption isotherms prevent false positive classification by VSSA. We find no false negatives by VSSA, neither in Tier 1 nor in Tier 2, despite real-world industrial polydispersity and diverse composition, shape, and coatings. The VSSA screening strategy is recommended for inclusion in a technical guidance for the implementation of the definition.
KW - Nanomaterial
KW - Nanomaterial classification
KW - Regulation
KW - VSSA
KW - Size measurement
KW - Particle size
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391450
DO - https://doi.org/10.1007/s11051-017-3741-x
SN - 1388-0764
SN - 1572-896X
VL - 19
IS - 2
SP - Article 61, 1
EP - 16
PB - Springer Nature
AN - OPUS4-39145
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, M.
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Oxidative ageing of elastomers: experiment and modelling
N2 - During an extensive test programme at the Bundesanstalt für Materialforschung und prüfung, material property changes of EPDM O-rings were investigated at different ageing times and two ageing temperatures of 125 ◦ C and 150 ◦ C. To exclude possible diffusion-limited oxidation (DLO) effects that can distort the data, IRHD microhardness measurements were taken over the cross section of compressed O-rings. Continuous stress relaxation measurements were taken on samples free of DLO effects. The additional effect of physical processes to irreversible chemical ones during a long-term thermal exposure is quantified by the analysis of compression set measurements under various test conditions. By combining the different experimental methods, characteristic times relative to the degradation processes were determined. On the basis of experimental data, a microphysically motivated model that takes into account reversible and irreversible processes was developed. The parameter identification strategy of the material model is based on our experimental investigations on homogeneously aged elastomer O-rings. The simulated results are in good agreement with the experiments.
KW - Compression Set
KW - Compression stress relaxation
KW - Modelling
KW - Ageing
KW - Microhardness
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609332
DO - https://doi.org/10.1007/s00161-022-01093-9
VL - 36
SP - 289
EP - 297
PB - Springer Nature
AN - OPUS4-60933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feltin, N.
A1 - Crouzier, L.
A1 - Delvallée, A.
A1 - Pellegrino, F
A1 - Maurino, V.
A1 - Bartczak, D.
A1 - Goenaga-Infante, H.
A1 - Taché, O.
A1 - Marguet, S.
A1 - Testard, F.
A1 - Artous, S.
A1 - Saint-Antonin, F.
A1 - Salzmann, Christoph
A1 - Deumer, J.
A1 - Gollwitzer, C.
A1 - Koops, R.
A1 - Sebaïhi, N.
A1 - Fontanges, R.
A1 - Neuwirth, M.
A1 - Bergmann, D.
A1 - Hüser, D.
A1 - Klein, T.
A1 - Hodoroaba, Vasile-Dan
T1 - Metrological Protocols for Reaching Reliable and SI-Traceable Size Results for Multi-Modal and Complexly Shaped Reference Nanoparticles
N2 - The study described in this paper was conducted in the framework of the European nPSize project (EMPIR program) with the main objective of proposing new reference certified nanomaterials for the market in order to improve the reliability and traceability of nanoparticle size measurements. For this purpose, bimodal populations as well as complexly shaped nanoparticles (bipyramids, cubes, and rods) were synthesized. An inter-laboratory comparison was organized for comparing the size measurements of the selected nanoparticle samples performed with electron microscopy (TEM, SEM, and TSEM), scanning probe microscopy (AFM), or small-angle X-ray scattering (SAXS). The results demonstrate good consistency of the measured size by the different techniques in cases where special care was taken for sample preparation, instrument calibration, and the clear definition of the measurand. For each characterization method, the calibration process is described and a semi-quantitative table grouping the main error sources is proposed for estimating the uncertainties associated with the measurements. Regarding microscopy-based techniques applied to complexly shaped nanoparticles, data dispersion can be observed when the size measurements are affected by the orientation of the nanoparticles on the substrate. For the most complex materials, hybrid approaches combining several complementary techniques were tested, with the outcome being that the reliability of the size results was improved.
KW - Certified reference nanomaterials
KW - Traceable nanoparticle size measurements;
KW - Hybrid metrology
KW - Scanning probe microscopy
KW - Small-angle X-ray scattering
KW - Electron microscopy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571902
DO - https://doi.org/10.3390/nano13060993
SN - 2079-4991
VL - 13
IS - 6 - Special Issue "Identification and Quantification of Nanomaterials"
SP - 1
EP - 25
PB - MDPI
CY - Basel, CH
AN - OPUS4-57190
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hülagü, Deniz
A1 - Tobias, Charlie
A1 - Climent Terol, Estela
A1 - Gojani, Ardian
A1 - Rurack, Knut
A1 - Hodoroaba, Vasile-Dan
T1 - Generalized Analysis Approach of the Profile Roughness by Electron Microscopy with the Example of Hierarchically Grown Polystyrene–Iron Oxide–Silica Core–Shell–Shell Particles
N2 - The roughness as a property of core–shell (CS) microparticles plays a key role in their functionality. Quantitative evaluation of the roughness of CS microparticles is, however, a challenging task with approaches using electron microscopy images being scarce and showing pronounced differences in terms of methodology and results. This work presents a generalized method for the reliable roughness determination of nonplanar specimens such as CS particles from electron microscopic images, the method being robust and reproducible with a high accuracy. It involves a self-written software package (Python) that analyzes the recorded images, extracts corresponding data, and calculates the roughness based on the deviation of the identified contour. Images of single particles are taken by a dual mode scanning electron microscopy (SEM) setup which permits imaging of the same field-of-view of the sample with high resolution and surface sensitive in SE InLens mode as well as in transmission mode (TSEM). Herein, a new type of polystyrene core–iron oxide shell–silica shell particles is developed to serve as a set of lower micrometer-sized study objects with different surface roughness; the analysis of their images by the semiautomatic workflow is demonstrating that the particles’ profile roughness can be quantitatively obtained.
KW - Core–shell particles
KW - Image analysis
KW - Nanoparticles
KW - Roughness
KW - SEM
KW - transmission mode
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542576
DO - https://doi.org/10.1002/adem.202101344
SP - 1
EP - 9
PB - Wiley-VCH
AN - OPUS4-54257
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
A1 - Jungnickel, H.
A1 - Tentschert, J.
A1 - Luch, A.
A1 - Sogne, V.
A1 - Maier, F.
A1 - Burr, L.
A1 - Schmid, D.
A1 - Yoon, T.-H.
A1 - Petters, R.
A1 - Briffa, S.M.
A1 - Valsami-Jones, E.
T1 - Automation and Standardization—A Coupled Approach Towards Reproducible Sample Preparation Protocols for Nanomaterial Analysis
N2 - Whereas the characterization of nanomaterials using different analytical techniques is often highly automated and standardized, the sample preparation that precedes it causes a bottleneck in nanomaterial analysis as it is performed manually. Usually, this pretreatment depends on the skills and experience of the analysts. Furthermore, adequate reporting of the sample preparation is often missing. In this overview, some solutions for techniques widely used in nano-analytics to overcome this problem are discussed. Two examples of sample preparation optimization by au-tomation are presented, which demonstrate that this approach is leading to increased analytical confidence. Our first example is motivated by the need to exclude human bias and focuses on the development of automation in sample introduction. To this end, a robotic system has been de-veloped, which can prepare stable and homogeneous nanomaterial suspensions amenable to a variety of well-established analytical methods, such as dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), field-flow fractionation (FFF) or single-particle inductively coupled mass spectrometry (sp-ICP-MS). Our second example addresses biological samples, such as cells exposed to nanomaterials, which are still challenging for reliable analysis. An air–liquid interface has been developed for the exposure of biological samples to nanomaterial-containing aerosols. The system exposes transmission electron microscopy (TEM) grids under reproducible conditions, whilst also allowing characterization of aerosol composition with mass spectrometry. Such an approach enables correlative measurements combining biological with physicochemical analysis. These case studies demonstrate that standardization and automation of sample preparation setups, combined with appropriate measurement processes and data reduction are crucial steps towards more reliable and reproducible data.
KW - Sample preparation
KW - Automation
KW - Nanomaterial analysis
KW - Standardization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543988
DO - https://doi.org/10.3390/molecules27030985
VL - 27
IS - 3
SP - 1
EP - 22
PB - MDPI
AN - OPUS4-54398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rades, Steffi
A1 - Hodoroaba, Vasile-Dan
A1 - Salge, T.
A1 - Wirth, Thomas
A1 - Lobera, M.P.
A1 - Labrador, R.H.
A1 - Natte, Kishore
A1 - Behnke, Thomas
A1 - Gross, Thomas
A1 - Unger, Wolfgang
T1 - High-resolution imaging with SEM/T-SEM, EDX and SAM as a combined methodical approach for morphological and elemental analyses of single engineered nanoparticles
N2 - The combination of complementary characterization techniques such as SEM (Scanning Electron Microscopy), T-SEM (Scanning Electron Microscopy in Transmission Mode), EDX (Energy Dispersive X-ray Spectroscopy) and SAM (Scanning Auger Microscopy) has been proven to be a powerful and relatively quick characterization strategy for comprehensive morphological and chemical characterization of individual silica and titania nanoparticles. The selected real life test materials, silica and titania, are listed in the OECD guidance manual as representative examples because they are often used as commercial nanomaterials. Imaging by high resolution SEM and in the transmission mode by T-SEM allows almost simultaneous surface and in-depth inspection of the same particle using the same instrument. EDX and SAM enable the chemical characterization of bulk and surface of individual nanoparticles. The core–shell properties of silica based materials are addressed as well. Titania nominally coated by silane purchased from an industrial source has been found to be inhomogeneous in terms of chemical composition.
KW - surface and in-depth inspection
KW - silica nanoparticles
KW - titania nanoparticles
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316296
DO - https://doi.org/10.1039/c4ra05092d
SN - 2046-2069
VL - 4
IS - 91
SP - 49577
EP - 49587
PB - RSC Publishing
CY - London
AN - OPUS4-31629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zaghdoudi, Maha
A1 - Kömmling, Anja
A1 - Jaunich, Matthias
A1 - Wolff, Dietmar
T1 - Scission, cross-linking, and physical relaxation during thermal degradation of elastomers
N2 - Elastomers are susceptible to chemical ageing, i.e., scission and cross-linking, at high temperatures. This thermally driven ageing process affects their mechanical properties and leads to limited operating time. Continuous and intermittent stress Relaxation measurements were conducted on ethylene propylene diene rubber (EPDM) and hydrogenated nitrile butadiene rubber (HNBR) samples for different ageing times and an ageing temperature of 125 °C. The contributions of chain scission and cross-linking were analysed for both materials at different ageing states, elucidating the respective ageing mechanisms. Furthermore, compression set experiments were performed under various test conditions. Adopting the two-network model, compression set values were calculated and compared to the measured data. The additional effect of physical processes to scission and cross-linking during a long-term thermal exposure is quantified through the compression set analysis. The characteristic times relative to the degradation processes are also determined.
KW - Ageing
KW - Scission
KW - Cross-linking
KW - Compression set
KW - Physical relaxation
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486091
DO - https://doi.org/10.3390/polym11081280
SN - 2073-4360
VL - 11
IS - 8
SP - 1280, 1
EP - 12
PB - MDPI
AN - OPUS4-48609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kömmling, Anja
A1 - Grelle, Tobias
A1 - Jaunich, Matthias
A1 - Goral, Milan
A1 - Wolff, Dietmar
T1 - Three-dimensional thermal expansion of neat and irradiated (U)HMWPE materials at elevated temperatures
N2 - The thermal expansion of polymeric parts can be an issue in many applications where the available space is limited, or exact dimensions of the part are required. For this study, a device was designed and built that allowed measuring the thermal expansion simultaneously in all three spatial directions on cubic samples with real-scale dimensions (78 mm edge length). The results are shown between 25 °C and 125 °C for two PE materials, one HMWPE and one tempered UHMWPE, for non-irradiated samples as well as cubes that have been irradiated with 100 and 400 kGy. The results measured with the new device were very similar to those measured with conventional thermo-mechanical analysis equipment and to literature data of UHMWPE. The HMWPE material shows a much larger thermal expansion coefficient in one direction compared to the other two directions during the first heating due to frozen stresses from the pressing step during material manufacturing. These stresses are mostly released by the expansion during the first heating, so that the expansion during the second heating is more uniform. The overall volumetric expansion is the same for both heating runs. By contrast, the tempered UHMWPE material shows no significant difference between first and second heating run, as the stresses from processing could already relax in the tempering step. The irradiation treatment does not affect the values significantly for the given test set-up.
KW - Lupolen
KW - Ultra high molecular weight polyethylene
KW - GUR
KW - Coefficient of thermal expansion
KW - High temperature
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563987
DO - https://doi.org/10.1016/j.polymertesting.2022.107841
SN - 0142-9418
VL - 117
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-56398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brighenti, Francesca
A1 - Caspani, Valeria Francesca
A1 - Costa, Giancarlo
A1 - Giordano, Pier Francesco
A1 - Limongelli, Maria Pina
A1 - Zonta, Daniele
T1 - Bridge management systems: A review on current practice in a digitizing world
N2 - Bridges are subject to a plethora of deterioration phenomena, such as corrosion, fatigue, and damaging events (e. g., truck impacts and earthquakes) that can affect their performance and compromise functionality and safety. These challenges, along with the expansion of physical infrastructures and limited economic resources, underscore the need for effective management systems to enhance the efficiency of maintenance activities. To address this need, bridge operators have developed Bridge Management Systems (BMSs), which assist in ensuring safe operations while optimizing budget allocation and intervention strategies. Existing state-of-the-art studies on BMSs, dating back several years, primarily focus on specific aspects of BMSs and do not provide exhaustive insight into the implemented processes. Consequently, a comprehensive analysis of the entire process is currently lacking. This review organizes and discusses the key features of existing BMSs and introduces a novel definition of BMS modules — data management, diagnosis, prognosis, and decision-making — where consensus is currently lacking. The paper covers the historical and current practices of the most common BMSs, outlining the main principles of each phase along with their critical aspects and future trends.
KW - Bridge management system
KW - Digitalization
KW - Automation
KW - Inspection
KW - Structural health monitoring
KW - Digital twin
KW - Decision making
KW - Life-cycle analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628380
DO - https://doi.org/10.1016/j.engstruct.2024.118971
SN - 0141-0296
VL - 321
SP - 1
EP - 21
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62838
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Colmenares, Daniel
A1 - Costa, Giancarlo
A1 - Civera, Marco
A1 - Surace, Cecilia
A1 - Karoumi, Raid
T1 - Quantification of the human–structure interaction effect through full-scale dynamic testing: The Folke Bernadotte Bridge
N2 - An analytical expression for the frequency response function of a coupled pedestrian-bridge system is presented and evaluated using an experimental measurement campaign performed on the Folke Bernadotte Bridge in Stockholm, Sweden. A finite element model and the modal models that consider the human–structure interaction effect are calibrated with respect to the measurements. The properties of the spring–mass–damper model representing the pedestrians were identified, considering the different structural modes of the system. Good agreement was obtained between the experimental and theoretical frequency response functions. A sensitivity analysis of the obtained solution was performed, validating the determined analytical expression for the frequency response function of the coupled pedestrian-bridge system that takes into account the human–structure interaction effect.
KW - Safety
KW - Building and Construction
KW - Architecture
KW - Civil and Structural Engineering
KW - Risk
KW - Reliability
KW - Quality
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584038
DO - https://doi.org/10.1016/j.istruc.2023.06.133
SN - 2352-0124
VL - 55
SP - 2249
EP - 2265
PB - Elsevier
AN - OPUS4-58403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costa, Giancarlo
A1 - Thöns, Sebastian
A1 - Limongelli, Maria Pina
A1 - Piscini, Andrea
T1 - Value of information‐driven innovation in Gerber saddles monitoring
N2 - AbstractInnovation plays a crucial role in shaping technological, economic, and social progress in modern societies. In the realm of bridge integrity management, the development and diffusion of technologies to acquire information can significantly enhance industries' safety and functionality capabilities. Among the most widely diffused bridge types in Europe and North America, Gerber bridges are particularly susceptible to deterioration over time. Gerber saddles are typically not instrumented and are checked only through visual inspections. This paper introduces the metric of the Value of Information for Innovation to estimate the benefit associated with introducing an established technology in a new market of application. Herein, the operational value of implementing microelectromechanical inclinometers in the integrity management of Gerber saddles is quantified for the specific case of a bridge in northern Italy. Microelectromechanical systems companies may use these results to optimally select the technology price, investigate diverse market strategies, and optimize sensor arrangement.
KW - Gerber saddles
KW - Innovation
KW - MEMs
KW - Sensor optimization
KW - Value of Information
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627853
DO - https://doi.org/10.1002/suco.202400951
SN - 1751-7648
VL - 674
SP - 230
EP - 240
PB - Wiley
AN - OPUS4-62785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arinchtein, A.
A1 - Ye, M.-Y.
A1 - Yang, Q.
A1 - Kreyenschulte, C.
A1 - Wagner, Andreas
A1 - Frisch, M.
A1 - Brückner, A.
A1 - Kondratenko, E.
A1 - Kraehnert, R.
T1 - Dynamics of Reaction-Induced Changes of Model-Type Iron Oxide Phases in the CO2-Fischer-Tropsch-Synthesis
N2 - Iron-based catalysts are employed in CO2-FTS due to their ability to convert CO2 into CO in a first step and their selectivity towards higher hydrocarbons in a second CO hydrogenation step. According to the literature, iron carbides represent the active phase for hydrocarbon formation and are claimed to emerge in the presence of CO. We propose nanostructured FeOx films as model systems to assess information about the complex phase transformations during CO2-FTS. Mesoporous hematite, ferrihydrite, maghemite, maghemite/magnetite films were exposed to CO2-FTS atmospheres at 20 bar and 300°C. Up to three distinct phases were observed depending on the timeon-stream (TOS): a sintered maghemite/magnetite phase, a carbidic core-shell structure, and a low-crystalline, needle-type oxide phase. Our findings indicate that the formation of an intermediary maghemite/magnetite phase, predominant after short TOS (30 h), precedes the evolution of the carbide phase.
Yet, even after prolonged TOS (185 h), no full conversion into a bulk carbide is observed.
KW - Nanostructured FeOx films
KW - CO2
KW - Scanning Auger Spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549709
DO - https://doi.org/10.1002/cctc.202200240
SN - 1867-3880
VL - 14
IS - 14
SP - 1
EP - 11
PB - Wiley-VCH
AN - OPUS4-54970
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Evans, Alexander
A1 - Mishurova, Tatiana
A1 - Ulbricht, Alexander
A1 - Sprengel, Maximilian
A1 - Serrano-Munoz, Itziar
A1 - Fritsch, Tobias
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
A1 - Bruno, Giovanni
T1 - Diffraction-Based Residual Stress Characterization in Laser Additive Manufacturing of Metals
N2 - Laser-based additive manufacturing methods allow the production of complex metal structures within a single manufacturing step. However, the localized heat input and the layer-wise manufacturing manner give rise to large thermal gradients. Therefore, large internal stress (IS) during the process (and consequently residual stress (RS) at the end of production) is generated within the parts. This IS or RS can either lead to distortion or cracking during fabrication or in-service part failure, respectively. With this in view, the knowledge on the magnitude and spatial distribution of RS is important to develop strategies for its mitigation. Specifically, diffraction-based methods allow the spatial resolved determination of RS in a non-destructive fashion. In this review, common diffraction-based methods to determine RS in laser-based additive manufactured parts are presented. In fact, the unique microstructures and textures associated to laser-based additive manufacturing processes pose metrological challenges. Based on the literature review, it is recommended to (a) use mechanically relaxed samples measured in several orientations as appropriate strain-free lattice spacing, instead of powder, (b) consider that an appropriate grain-interaction model to calculate diffraction-elastic constants is both material- and texture-dependent and may differ from the conventionally manufactured variant. Further metrological challenges are critically reviewed and future demands in this research field are discussed.
KW - Laser-based additive manufacturing
KW - Residual stress analysis
KW - X-ray and neutron diffraction
KW - Diffraction-elastic constants
KW - Strain-free lattice spacing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538054
DO - https://doi.org/10.3390/met11111830
VL - 11
IS - 11
SP - 1830
PB - MPDI
CY - Basel
AN - OPUS4-53805
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tengattini, A
A1 - Kardjilov, N
A1 - Helfen, L
A1 - Douissard, P A
A1 - Lenoir, N
A1 - Markötter, Henning
A1 - Hilger, A
A1 - Arlt, T
A1 - Paulisch, M
A1 - Turek, T
A1 - Manke, Ingo
T1 - Compact and versatile neutron imaging detector with sub-4μm spatial resolution based on a single-crystal thin-film scintillator
N2 - A large and increasing number of scientific domains pushes for high neutron imaging resolution achieved in reasonable times. Here we present the principle, design and performance of a detector based on infinity corrected optics combined with a crystalline Gd3Ga5O12 : Eu scintillator, which provides an isotropic sub-4 μm true resolution. The exposure times are only of a few minutes per image. This is made possible also by the uniquely intense cold neutron flux available at the imaging beamline NeXT-Grenoble. These comparatively rapid acquisitions are compatible with multiple high quality tomographic acquisitions, opening new venues for in-operando testing, as briefly exemplified here.
KW - Neutron imaging
KW - Scintillator
KW - Resolution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549836
DO - https://doi.org/10.1364/oe.448932
VL - 30
IS - 9
SP - 14461
EP - 14477
PB - Optica
CY - Washington, DC
AN - OPUS4-54983
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mani, Deepak
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Diffraction Enhanced Imaging Analysis with Pseudo-Voigt Fit Function
N2 - Diffraction enhanced imaging (DEI) is an advanced digital radiographic imaging technique employing the refraction of X-rays to contrast internal interfaces. This study aims at qualitatively and quantitatively evaluating images acquired using this technique and to assess how different fitting functions to the typical rocking curves (RCs) influence the quality of images. RCs are obtained for every image pixel. This allows the separate determination of the absorption and the refraction properties of the material in a position-sensitive manner. Comparison of various types of fitting functions reveals that the Pseudo-Voigt (PsdV) function is best suited to fit typical RCs. A robust algorithm was developed in the Python programming language, which reliably extracts the physically meaningful information from each pixel of the image. We demonstrate the potential of the algorithm with two specimens: a silicone gel specimen that has well-defined interfaces, and an additively manufactured polycarbonate specimen.
KW - Diffraction Enhanced Imaging
KW - Analyzer-Based Imaging
KW - X-ray refraction
KW - Non-Destructive Evaluation
KW - Pseudo-Voigt fit function
KW - Python
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553791
DO - https://doi.org/10.3390/jimaging8080206
SN - 2313-433X
VL - 8
IS - 8
SP - 1
EP - 13
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Al-Falahat, A M
A1 - Kardjilov, N
A1 - Woracek, R
A1 - Boin, M
A1 - Markötter, Henning
A1 - Kuhn, L T
A1 - Makowska, M
A1 - Strobl, M
A1 - Pfretzschner, B
A1 - Banhart, J
A1 - Manke, I
T1 - Temperature dependence in Bragg edge neutron transmission measurements
N2 - A systematic study has been carried out to investigate the neutron transmission signal as a function of sample temperature. In particular, the experimentally determined wavelength-dependent neutron attenuation spectra for a martensitic steel at temperatures ranging from 21 to 700°C are compared with simulated data. A theoretical description that includes the Debye–Waller factor in order to describe the temperature influence on the neutron cross sections was implemented in the nxsPlotter software and used for the simulations. The analysis of the attenuation coefficients at varying temperatures shows that the missing contributions due to elastic and inelastic scattering can be clearly distinguished: while the elastically scattered intensities decrease with higher temperatures, the inelastically scattered intensities increase, and the two can be separated from each other by analysing unique sharp features in the form of Bragg edges. This study presents the first systematic approach to quantify this effect and can serve as a basis , for example, to correct measurements taken during in situ heat treatments, in many cases being a prerequisite for obtaining quantifiable results.
KW - Neutron Bragg edge imaging
KW - Debye–Waller factor
KW - Temperature-dependent neutron transmission
KW - Super martensitic stainless steel
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556896
DO - https://doi.org/10.1107/S1600576722006549
VL - 55
IS - Pt 4
SP - 919
EP - 928
PB - International Union of Crystallography
AN - OPUS4-55689
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Mieller, Björn
A1 - Moos, R.
A1 - Rabe, Torsten
T1 - Lowering the sintering temperature of calcium manganate for thermoelectric applications
N2 - This study combines three different approaches to lower the sintering temperature of Sm-doped CaMnO3 to save energy in production and facilitate co-firing with other low-firing oxides or metallization. The surface energy of the powder was increased by fine milling, sintering kinetics were enhanced by additives, and uniaxial pressure during sintering was applied. The shrinkage, density, microstructure, and thermoelectric properties were evaluated. Compared to micro-sized powder, the use of finely ground powder allows us to lower the sintering temperature by 150 K without reduction of the power factor. By screening the effect of various common additives on linear shrinkage of CaMnO3 after sintering at 1100 ○C for 2 h, CuO is identified as the most effective additive. Densification at sintering temperatures below 1000 ○C can be significantly increased by pressure-assisted sintering. The power factor at room temperature of CaMnO3 nano-powder sintered at 1250 ○C was 445 μW/(m K2). Sintering at 1100 ○C reduced the power factor to 130 μW/(m K2) for CaMnO3 nano-powder, while addition of 4 wt.% CuO to the same powder led to ∼290 μW/(m K2). The combination of fine milling, CuO addition, and pressureassisted sintering at 950 ○C resulted in a power factor of ∼130 μW/(m K2). These results show that nano-sized powder and CuO addition are successful and recommendable strategies to produce CaMnO3 with competitive properties at significantly reduced temperatures and dwell times.
KW - Sintering additive
KW - Liquid phase sintering
KW - Pressure assisted sintering
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555467
DO - https://doi.org/10.1063/5.0098015
SN - 2158-3226
VL - 12
IS - 8
SP - 1
EP - 9
PB - American Institute of Physics (AIP)
CY - New York, NY
AN - OPUS4-55546
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markötter, Henning
A1 - Sintschuk, Michael
A1 - Britzke, Ralf
A1 - Dayani, Shahabeddin
A1 - Bruno, Giovanni
T1 - Upgraded imaging capabilities at the BAMline (BESSY II)
N2 - The BAMline at the BESSY II synchrotron X-ray source has enabled research for more than 20 years in widely spread research fields such as materials science, biology, cultural heritage and medicine. As a nondestructive characterization method, synchrotron X-ray imaging, especially tomography, plays a particularly important role in structural characterization. A recent upgrade of key equipment of the BAMline widens its imaging capabilities: shorter scan acquisition times are now possible, in situ and operando studies can now be routinely performed, and different energy spectra can easily be set up. In fact, the upgraded double-multilayer monochromator brings full flexibility by yielding different energy spectra to optimize flux and energy resolution as desired. The upgraded detector (based on an sCMOS camera) also allows exploiting the higher flux with reduced readout times. Furthermore, an installed slip ring allows the sample stage to continuously rotate. The latter feature enables tomographic observation of processes occurring in the time scale of a few seconds.
KW - Synchrotron radiation
KW - Computed tomography
KW - Double-multilayer monochromators
KW - Pink beams
KW - X-ray optics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556907
DO - https://doi.org/10.1107/S1600577522007342
SN - 1600-5775
VL - 29
IS - Pt 5
SP - 1292
EP - 1298
PB - International Union of Crystallography
CY - Chester
AN - OPUS4-55690
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Stegemann, R.
A1 - Lyamkin, V.
A1 - Cabeza, S.
A1 - Evsevleev, S.
A1 - Pelkner, Matthias
A1 - Bruno, Giovanni
T1 - Subsurface and Bulk Residual Stress Analysis of S235JRC + C Steel TIG Weld by Diffraction and Magnetic Stray Field Measurements
N2 - Background Due to physical coupling between mechanical stress and magnetization in ferromagnetic materials, it is assumed in the literature that the distribution of the magnetic stray field corresponds to the internal (residual) stress of the specimen.
The correlation is, however, not trivial, since the magnetic stray field is also influenced by the microstructure and the geometry of component. The understanding of the correlation between residual stress and magnetic stray field could help to evaluate the integrity of welded components.
Objective This study aims at understanding the possible correlation of subsurface and bulk residual stress with magnetic stray field in a low carbon steel weld. Methods The residual stress was determined by synchrotron X-ray diffraction (SXRD, subsurface region) and by neutron diffraction (ND, bulk region). SXRD possesses a higher spatial resolution than ND. Magnetic stray fields were mapped by utilizing high-spatial-resolution giant magneto resistance (GMR) sensors.
Results The subsurface residual stress overall correlates better with the magnetic stray field distribution than the bulk stress.
This correlation is especially visible in the regions outside the heat affected zone, where the influence of the microstructural features is less pronounced but steep residual stress gradients are present.
Conclusions It was demonstrated that the localized stray field sources without any obvious microstructural variations are associated with steep stress gradients. The good correlation between subsurface residual stress and magnetic signal indicates that the source of the magnetic stray fields is to be found in the range of the penetration depth of the SXRD measurements.
KW - Residual stress
KW - Magnetic stray field
KW - Synchrotron X-ray diffraction
KW - Neutron diffraction
KW - TIG welding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547419
DO - https://doi.org/10.1007/s11340-022-00841-x
VL - 62
IS - 6
SP - 1017
EP - 1025
PB - Springer
AN - OPUS4-54741
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
T1 - Micro Non-Destructive Testing and Evaluation
N2 - What is meant by ‘Micro Non-Destructive Testing and Evaluation’? This was the central subject of debate in this Special Issue.
At present, sub-millimeter-size components or even assemblies are pervading the industrial and scientific world. Classic examples are electronic devices and watches (as well as parts thereof), but recent examples encompass additively manufactured lattice structures, stents, or other microparts. Moreover, most assemblies contain micro-components. Testing such components or their miniaturized parts would fit well within the topic of micro non-destructive testing and evaluation.
In all cases, performance and integrity testing, quality control, and dimensional tolerances need to be measured at the sub-millimeter level (ideally with a spatial resolution of about a micron); most of the time, such features and components are embedded in much larger assemblies, which also need to be taken into account. The solution to this dilemma (i.e. measuring large parts with high resolution) depends on the part and on the problem under consideration.
Another possible definition of micro non-destructive testing and evaluation can relate to the characterization of micro-features (e.g., the microstructure) in much larger specimens, such as damage in concrete cores or porosity in additively manufactured components. A further aspect is the use of microscopic probes to evaluate macroscopic properties. This is the case, for instance but not at all exclusively, in the use of diffraction techniques to determine macroscopic stress.
The splits between testing and characterization at the micro-level (or of micro parts) from one side and handling of macroscopic assemblies on the other represent a great challenge for many fields of materials characterization. On top of that, including the use of microscopic methods to test integrity would add a further level of complexity.
Imaging, mechanical testing, non-destructive testing, measurement of properties, structural health monitoring, and dimensional metrology all need to be re-defined if we want to cope with the multi-faceted topic of micro non-destructive testing and evaluation.
The challenge has already been accepted by the scientific and engineering communities for a while but is still far from being universally tackled. This Special Issue yields an interesting answer to the questions posed above. It presents the progress made and the different aspects of the challenge as well as at indicates the paths for the future of NDT&E.
KW - Ultrasound
KW - Materials Characterization
KW - Residual Stress
KW - Thermography Computed
KW - Tomography
KW - Non-destructive Testing
KW - Magnetic Methods
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556849
DO - https://doi.org/10.3390/ma15175923
VL - 15
IS - 17
SP - 1
EP - 3
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-55684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bruno, Giovanni
A1 - Maierhofer, Christiane
T1 - Advanced Characterization and On-Line Process Monitoring of Additively Manufactured Materials and Components
N2 - Additive manufacturing (AM) techniques have risen to prominence in many industrial sectors. This rapid success of AM is due to the freeform design, which offers enormous possibilities to the engineer, and to the reduction of waste material, which has both environmental and economic advantages. Even safety-critical parts are now being produced using AM. This enthusiastic penetration of AM in our daily life is not yet paralleled by a thorough characterization and understanding of the microstructure of materials and of the internal stresses of parts. The same holds for the understanding of the formation of defects during manufacturing. While simulation efforts are sprouting and some experimental techniques for on-line monitoring are available, still little is known about the propagation of defects throughout the life of a component (from powder to operando/service conditions). This Issue was aimed at collecting contributions about the advanced characterization of AM materials and components (especially at large-scale experimental facilities such as Synchrotron and Neutron sources), as well as efforts to liaise on-line process monitoring to the final product, and even to the component during operation. The goal was to give an overview of advances in the understanding of the impacts of microstructure and defects on component performance and life at several length scales of both defects and parts.
KW - Non-destructive Testing
KW - Additive Manufacturing
KW - Materials Characterization
KW - Online Monitoring
KW - Residual Stress
KW - Thermography
KW - Computed Tomography
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556833
DO - https://doi.org/10.3390/met12091498
VL - 12
IS - 9
SP - 1
EP - 3
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-55683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bresch, Sophie
A1 - Stargardt, Patrick
A1 - Moos, Ralf
A1 - Mieller, Björn
T1 - Co‐Fired Multilayer Thermoelectric Generators Based on Textured Calcium Cobaltite
N2 - Thermoelectric generators are very attractive devices for waste heat energy harvesting as they transform a temperature difference into electrical power. However, commercially available generators show poor power density and limited operation temperatures. Research focuses on high‐temperature materials and innovative generator designs. Finding the optimal design for a given material system is challenging. Here, a theoretical framework is provided that allows appropriate generator design selection based on the particular material properties. For high‐temperature thermoelectric oxides, it can be clearly deduced that unileg multilayer generators have the highest potential for effective energy harvesting. Based on these considerations, prototype unileg multilayer generators from the currently best thermoelectric oxide Ca3Co4O9 are manufactured for the first time by industrially established ceramic multilayer technology. These generators exhibit a power density of 2.2 mW/cm² at a temperature difference of 260 K, matching simulated values and confirming the suitability of the technology. Further design improvements increase the power density by a factor of 22 to facilitate practicable power output at temperature differences as low as 7 K. This work demonstrates that reasonable energy harvesting at elevated temperatures is possible with oxide materials and appropriate multilayer design.
KW - Optical and Magnetic Materials
KW - Electronic
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596306
DO - https://doi.org/10.1002/aelm.202300636
SN - 2199-160X
VL - 10
IS - 3
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-59630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fardan, Ahmed
A1 - Fazi, Andrea
A1 - Peng, Ru Lin
A1 - Mishurova, Tatiana
A1 - Thuvander, Mattias
A1 - Bruno, Giovanni
A1 - Brodin, Håkan
A1 - Hryha, Eduard
T1 - Fine-Tuning Melt Pools and Microstructures: Taming Cracks in Powder Bed Fusion—Laser Beam of a non-weldable Ni-base Superalloy
N2 - Powder Bed Fusion – Laser Beam (PBF-LB) of high γ’ strengthened Ni-base superalloys, such as CM247LC, is of great interest for high temperature applications in gas turbines. However, PBF-LB of CM247LC is challenging due to the high cracking susceptibility during PBF-LB processing (solidification cracking) and heat treatment (strain age cracking, mostly caused by residual stresses). This study focuses on understanding the impact of process parameters on microstructure, residual stresses and solidification cracking. Laser power (P), speed (v) and hatch spacing (h) were varied while the layer thickness (t) was fixed. The melt pool size and shape were found to be key factors in minimizing solidification cracking. Narrower and shallower melt pools, achieved using a low line energy density (LED = P/v ≤ 0.1 J/mm), gave low crack densities (0.7 mm/mm2). A tight hatch spacing (h = 0.03 mm) resulted in reduced lack of fusion porosity. Electron backscatter diffraction investigations revealed that parameters giving finer microstructure with 〈100〉crystallographic texture had low crack densities provided they were processed with a low LED. Atom probe tomography elucidated early stages of spinodal decomposition in the as-built condition, where Cr and Al cluster separately. The extent of spinodal decomposition was found to be affected by the LED and the hatch spacing. Samples with low LED and small hatch spacing showed higher degrees of spinodal decomposition. X-ray diffraction residual stress investigations revealed that the residual stress is proportional to the volumetric energy density (VED = P/(v. h. t)). Although low residual stresses can be achieved by using low VED, there is a high risk of lack of fusion. Hence, other parameters such as modified scan strategy, build plate pre-heating and pulsed laser mode, must be further explored to minimize the residual stresses to reduce the strain age cracking susceptibility.
KW - Additive manufacturing
KW - X-ray CT
KW - Non-weldable superalloy
KW - Solidification cracking
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597340
DO - https://doi.org/10.1016/j.mtla.2024.102059
SN - 2589-1529
VL - 34
IS - 102059
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-59734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Mishurova, Tatiana
A1 - Evans, Alexander
A1 - Fitch, Andrew N.
A1 - Haubrich, Jan
A1 - Requena, Guillermo
A1 - Bruno, Giovanni
A1 - Serrano-Munoz, Itziar
T1 - Evolution of interphase stress over a crack propagation plane as a function of stress relief heat treatments in a PBF‐LB/M AlSi10Mg alloy
N2 - AbstractIn this study, we compare the residual stress state in a laser powder bed fusion (PBF‐LB/M) AlSi10Mg alloy in the as‐built (AB) condition with that after two different heat treatments (265 °C for 1 h, HT1; and 300 °C for 2 h, HT2). The bulk residual stress (RS) is determined using synchrotron X‐ray diffraction (SXRD), and near‐surface profiles are determined using laboratory energy‐dispersive X‐ray diffraction (EDXRD). The EDXRD results do not reveal any notable difference between the conditions at a depth of 350 μm, suggesting that the machining process yields a comparable residual stress state in the near‐surface regions. On the other hand, the SXRD results show that HT1 is more effective in relieving the bulk RS. It is observed that HT1 reduces the RS state in both the aluminium matrix and the silicon network. In addtion, HT2 does not have a significant impact on relaxing the RS as‐built state of the matrix, although it does induce a reduction in the RS magnitudes of the Si phase. It is concluded that the heat treatment stress relieving is effective as long as the Si‐network is not disaggregated.
KW - Interphase residual stress
KW - Laboratory energy-dispersive X-ray diffraction (EDXRD)
KW - PBFLB/M AlSi10Mg alloy
KW - Stress-relief heat-treatments
KW - Synchrotron X-ray diffraction (SXRD)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597591
DO - https://doi.org/10.1111/str.12475
VL - 60
IS - 6
SP - 1
EP - 13
PB - John Wiley & Sons Ltd.
AN - OPUS4-59759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cabo Rios, Alberto
A1 - Mishurova, Tatiana
A1 - Cordova, Laura
A1 - Persson, Mats
A1 - Bruno, Giovanni
A1 - Olevsky, Eugene
A1 - Hryha, Eduard
T1 - Ex-situ characterization and simulation of density fluctuations evolution during sintering of binder jetted 316L
N2 - Efficient density evolution during sintering of the as-printed component is vital to reach full densification and required properties of binder jet (BJT) components. However, due to the high porosity and brittle nature of the green compact, analysis of the microstructure development during sintering is very difficult, resulting in lack of understanding of the densification process. Density development from green state (57 ± 1.6 %) up to full density (99 ± 0.3 %) was characterized by high-resolution synchrotron X-Ray computed tomography (SXCT) on BJT 316L samples from ex-situ interrupted sintering tests. Periodicity of density fluctuations along the building direction was revealed for the first time and was related to the layer thickness of ~ 42 μm during printing that decreased down to ~ 33 μm during sintering. Sintering simulations, utilizing a continuum sintering model developed for BJT, allowed to replicate the density evolution during sintering with a mean error of 2 % and its fluctuation evolution from green (1.66 %) to sintered (0.56 %) state. Additionally, simulation of extreme particle size segregation (1 μm to 130 μm) suggested that non-optimized printing could lead to undesirable density fluctuation amplitude rapid increase (~10 %) during sintering. This might trigger the nucleation of defects (e.g., layer delamination, cracking, or excessive residual porosity) during the sintering process.
KW - Additive manufacturing
KW - Synchrotron X-ray CT
KW - Binder Jetting
KW - Sintering
KW - FEM Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594389
DO - https://doi.org/10.1016/j.matdes.2024.112690
SN - 0264-1275
VL - 238
SP - 1
EP - 18
PB - Elsevier
AN - OPUS4-59438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alekseychuk, V. O.
A1 - Kupsch, Andreas
A1 - Plotzki, D.
A1 - Bellon, Carsten
A1 - Bruno, Giovanni
T1 - Simulation-Assisted Augmentation of Missing Wedge and Region-of-Interest Computed Tomography Data
N2 - This study reports a strategy to use sophisticated, realistic X-ray Computed Tomography (CT) simulations to reduce Missing Wedge (MW) and Region-of-Interest (RoI) artifacts in FBP (Filtered Back-Projection) reconstructions. A 3D model of the object is used to simulate the projections that include the missing information inside the MW and outside the RoI. Such information augments the experimental projections, thereby drastically improving the reconstruction results. An X-ray CT dataset of a selected object is modified to mimic various degrees of RoI and MW problems. The results are evaluated in comparison to a standard FBP reconstruction of the complete dataset. In all cases, the reconstruction quality is significantly improved. Small inclusions present in the scanned object are better localized and quantified. The proposed method has the potential to improve the results of any CT reconstruction algorithm.
KW - Computed tomography
KW - Missing wedge
KW - Region of interest
KW - Augmented data
KW - CT simulation
KW - aRTist
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593799
UR - https://www.mdpi.com/2313-433X/10/1/11
DO - https://doi.org/10.3390/jimaging10010011
SN - 2313-433X
VL - 10
IS - 1
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-59379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tsamos, Athanasios
A1 - Evsevleev, Sergei
A1 - Fioresi, Rita
A1 - Faglioni, Francesco
A1 - Bruno, Giovanni
T1 - A Complete Strategy to Achieve High Precision Automatic Segmentation of Challenging Experimental X‐Ray Computed Tomography Data Using Low‐Resemblance Synthetic Training Data
N2 - It is shown that preconditioning of experimental X‐ray computed tomography (XCT) data is critical to achieve high‐precision segmentation scores. The challenging experimental XCT datasets and deep convolutional neural networks (DCNNs) are used that are trained with low‐resemblance synthetic XCT data. The material used is a 6‐phase Al–Si metal matrix composite‐reinforced with ceramic fibers and particles. To achieve generalization, in our past studies, specific data augmentation techniques were proposed for the synthetic XCT training data. In addition, two toolsets are devised: (1) special 3D DCNN architecture (3D Triple_UNet), slicing the experimental XCT data from multiple views (MultiView Forwarding), the i.S.Sy.Da.T.A. iterative segmentation algorithm, and (2) nonlocal means (NLM) conditioning (filtering) for the experimental XCT data. This results in good segmentation Dice scores across all phases compared to more standard approaches (i.e., standard UNet architecture, single view slicing, standard single training, and NLM conditioning). Herein, the NLM filter is replaced with the deep conditioning framework BAM SynthCOND introduced in a previous publication, which can be trained with synthetic XCT data. This leads to a significant segmentation precision increase for all phases. The proposed methods are potentially applicable to other materials and imaging techniques.
KW - Automatic Segmentation
KW - XCT
KW - Artificial Intelligence
KW - Synthetic Training Data
KW - i.S.Sy.Da.T.A.
KW - BAM SynthMAT
KW - BAM SynthCOND
KW - Triple UNet
KW - Convolutional Neural Network (DCNN)
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590912
DO - https://doi.org/10.1002/adem.202301030
SN - 1438-1656
VL - 26
IS - 2
SP - 1
EP - 9
PB - Wiley online library
AN - OPUS4-59091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trogadas, P.
A1 - Cho, J. I. S.
A1 - Rasha, L.
A1 - Lu, X.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Manke, I.
A1 - Shearing, P. R.
A1 - Brett, D. J. L.
A1 - Coppens, M. O.
T1 - A nature-inspired solution for water management in flow fields for electrochemical devices
N2 - A systematic, nature-inspired chemical engineering approach is employed to solve the issue of flooding in electrochemical devices. The mechanism of passive water transport utilized by lizards living in arid environments is leveraged to design flow-fields with a microchannel structure on their surface, through which capillary pressure rapidly removes the water generated in the electrochemical device. This water management strategy is implemented in proton exchange membrane fuel cells (PEMFCs) with a lunginspired flow-field, which ensures uniform distribution of reactants across the catalyst layer. Jointly, this nature-inspired approach results in flood-free, stable operation at 100% RH and a B60% increase in current (B1.9 A cm-2) and peak power density (B650 mW cm−2) compared to current PEMFCs with a flood-prone, serpentine flow-field (B0.8 A cm-2 and 280 mW cm-2, respectively). This significant advance allows for PEMFC operation at fully humidified conditions.
KW - Neutron imaging
KW - X-ray tomography
KW - Fuel cell
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596662
DO - https://doi.org/10.1039/d3ee03666a
VL - 17
SP - 2007
EP - 2017
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martínez, E.
A1 - Lejeune, N.
A1 - Frechilla, J.
A1 - Porta-Velilla, L.
A1 - Forneau, E.
A1 - Angurel, L. A.
A1 - de la Fuente, G. F.
A1 - Bonse, Jörn
A1 - Silhanek, A. V.
A1 - Badía-Majós, A.
T1 - Laser engineered architectures for magnetic flux manipulation on superconducting Nb thin films
N2 - Custom shaped magnetic flux guiding channels have been fabricated on superconducting Nb thin films by laser nanopatterning of their surface. Preferential pathways are defined by suitable combination of imprinted anisotropic pinning domains through laser-induced periodic surface structures (LIPSS). Generated by the selective energy deposition of femtosecond UV laser pulses, quasi-parallel ripple structures are formed under optimized irradiation conditions. On average, each domain is formed by grooves with a lateral period of 260–270 nm and a depth about 80 nm. By combination of scanning and transmission electron microscopy, magneto-optical imaging, and conductive atomic force microscopy techniques, we conclude that the boundaries of the LIPSS-covered domains play a prominent role in the magnetic flux diversion process within the film. This is confirmed by dedicated modeling of the flux dynamics, combined with the inversion of the magneto-optical signal. The created metasurfaces enable control of the flux penetration process at the microscale.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Magnetic flux
KW - Magneto-optical imaging (MOI)
KW - Critical current density
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611243
UR - https://www.sciencedirect.com/science/article/pii/S0169433224019287
DO - https://doi.org/10.1016/j.apsusc.2024.161214
SN - 1873-5584 (Online)
SN - 0169-4332 (Print)
VL - 679
SP - 1
EP - 12
PB - Elsevier
AN - OPUS4-61124
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wonneberger, R.
A1 - Gräf, S.
A1 - Bonse, Jörn
A1 - Wisniewski, W.
A1 - Freiberg, K.
A1 - Hafermann, M.
A1 - Ronning, C.
A1 - Müller, F. A.
A1 - Undisz, A.
T1 - Tracing the Formation of Femtosecond Laser-Induced Periodic Surface Structures (LIPSS) by Implanted Markers
N2 - The generation of laser-induced periodic surface structures (LIPSS) using femtosecond lasers facilitates the engineering of material surfaces with tailored functional properties. Numerous aspects of their complex formation process are still under debate, despite intensive theoretical and experimental research in recent decades. This particularly concerns the challenge of verifying approaches based on electromagnetic effects or hydrodynamic processes by experiment. In the present study, a marker experiment is designed to conclude on the formation of LIPSS. Well-defined concentration depth profiles of 55Mn+- and 14N+-ions were generated below the polished surface of a cast Mn- and Si-free stainless steel AISI 316L using ion implantation. Before and after LIPSS generation, marker concentration depth profiles and the sample microstructure were evaluated by using transmission electron microscopy techniques. It is shown that LIPSS predominantly formed by material removal through locally varying ablation. Local melting and resolidification with the redistribution of the material occurred to a lesser extent. The experimental design gives quantitative access to the modulation depth with a nanometer resolution and is a promising approach for broader studies of the interactions of laser beams and material surfaces. Tracing LIPSS formation enables to unambiguously identify governing aspects, consequently guiding the path to improved processing regarding reproducibility, periodicity, and alignment.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Femtosecond laser processing
KW - Ion implantation
KW - Transmission Electron Microscopy (TEM)
KW - Stainless steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623990
DO - https://doi.org/10.1021/acsami.4c14777
SN - 1944-8244 (Print)
SN - 1944-8252 (Online)
VL - 17
IS - 1
SP - 2462
EP - 2468
PB - ACS Publications
AN - OPUS4-62399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kulkarni, Kajol
A1 - Kemmler, Samuel
A1 - Schwartz, Anna
A1 - Gedik, Gülçin
A1 - Chen, Yanxiang
A1 - Papageorgiou, Dimitrios
A1 - Kavroulakis, Ioannis
A1 - Iakymchuk, Roman
T1 - Harvesting energy consumption on European HPC systems: Sharing Experience from the CEEC project
N2 - Energy efficiency has emerged as a central challenge for modern high-performance computing (HPC) systems, where escalating computational demands and architectural complexity have led to significant energy footprints. This paper presents the collective experience of the EuroHPC JU Center of Excellence in Exascale CFD (CEEC) in measuring, analyzing, and optimizing energy consumption across major European HPC systems. We briefly review key methodologies and tools for energy measurement as well as define metrics for reporting results. Through case studies using representative CFD applications (waLBerla, FLEXI/GALÆXI, Neko, and NekRS), we evaluate energy-to-solution and time-to-solution on diverse architectures, including CPU- and GPU-based partitions of LUMI, MareNostrum5, MeluXina, and JUWELS Booster. Our results highlight the advantages of accelerators and mixed-precision techniques for reducing energy consumption while maintaining computational accuracy. Finally, we advocate the need to facilitate energy measurements on HPC systems in order to raise awareness, teach the community, and take actions toward more sustainable exascale computing.
T2 - SCA/HPCAsiaWS 2026: SCA/HPCAsia 2026 Workshops: Supercomputing Asia and International Conference on High Performance Computing in Asia Pacific Region Workshops
CY - Osaka , Japan
DA - 26.01.2026
KW - Energy consumption
KW - eEergy measurement
KW - Energy-to-solution
KW - Mixed-precision
KW - HPC
KW - CFD
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654175
DO - https://doi.org/10.1145/3784828.3785161
SP - 40
EP - 49
PB - ACM
CY - New York, NY, USA
AN - OPUS4-65417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mantouvalou, I.
A1 - Bauer, L.J.
A1 - Truong, V.-B.
A1 - Wagener, Y.
A1 - Förste, F.
A1 - Maruchenko, O.
A1 - Werner, S.
A1 - Lizzi, F.
A1 - Wieder, Frank
A1 - Wolff, T.
A1 - Kanngießer, B.
A1 - Zaslansky, P.
T1 - Quantitative micro-XRF combined with X-ray imaging reveals correlations between Zn concentration and dentin tubule porosity across entire teeth
N2 - Bony materials are biogenic composites of protein fibers and mineral that create hierarchical structures. In the case of teeth, dentin is the main component and similar to other bones, it contains porosity at multiple length scales. It is traversed by micron-sized hollow channels known as dentinal tubules, essential for temperature and pain sensation. Tubule density and thus porosity vary throughout the macroscopic three-dimensional (3D) structure, with porosity increasing toward the pulp. The different densities in teeth are easily revealed non-destructively in 3D by X-ray imaging using computer tomography (CT). Yet elemental composition analysis is more difficult to obtain from within the centimeter-sized heterogeneous bulk material. We describe an approach of merging CT measurements of healthy, intact bovine teeth with micro-X-ray fluorescence (micro-XRF) images of matching serially sectioned slices. Through the combination of multi-resolution quantitative CT measurements with elemental mass fraction derivation, gradients in density and element distributions such as calcium (Ca), phosphorus (P), and zinc (Zn) are revealed across entire teeth in 3D. While the main constituents (Ca and P) are homogeneously distributed in the matrix, Zn concentration increases significantly and exponentially toward the pulp. We find an inverse association between dentin tissue density and Zn concentration localizing this element in or around tubules. Our data serve as a quantitative reference for density and Zn mass fractions in healthy, neither carious nor hypermineralized dentin, as a basis for comparisons across species in health and disease states.
KW - Dentin density
KW - Micro-computer tomography
KW - Quantitative micro-X-ray fluorescence
KW - Tubule porosity
KW - Zn distribution
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654215
DO - https://doi.org/10.1002/VIW.20250173
SN - 2688-3988
SN - 2688-268X
SP - 1
EP - 14
PB - Wiley Online Library
AN - OPUS4-65421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Obenlüneschloß, Jorit
A1 - Boysen, Nils
A1 - Rönnby, Karl
A1 - Muriqi, Arbresha
A1 - Hoffmann, Volker
A1 - Abad Andrade, Carlos Enrique
A1 - Rogalla, Detlef
A1 - Brokmann, Ulrike
A1 - Rädlein, Edda
A1 - Nolan, Michael
A1 - Devi, Anjana
T1 - Ein seltener mononuklearer Lithium‐Carben‐Komplex für die Atomlagenabscheidung von lithiumhaltigen Dünnschichten
N2 - KurzfassungLithium ist das zentrale Element moderner Batterietechnologien, und die Herstellung von lithiumhaltigen Materialien mittels Atomlagenabscheidung (engl. Atomic Layer Deposition, ALD) bietet erhebliche Vorteile bei der Kontrolle der Schichtdicke und ‐zusammensetzung. In dieser Studie wird ein neuer mononuklearer, durch ein N‐heterocyclisches Carben (NHC) stabilisierter Lithiumkomplex, [Li(tBuNHC)(hmds)], als vielversprechender Präkursor für die ALD von lithiumhaltigen Dünnschichten vorgestellt. Die strukturelle Charakterisierung erfolgt durch den Vergleich von Dichtefunktionaltheorie (DFT) und Einkristall‐Röntgenbeugung (engl. Single‐Crystal X‐ray Diffraction, SC‐XRD), wobei die seltene mononukleare Struktur bestätigt wird. Thermogravimetrische Analysen (TGA) zeigen vorteilhafte thermische Eigenschaften für ALD‐Anwendungen. Die Verbindung weist einen niedrigen Schmelzpunkt, saubere Verdampfung und ermutigende Volatilitätsparameter im Vergleich zu anderen Lithium‐Präkursoren auf. ALD‐Experimente mit [Li(tBuNHC)(hmds)] und Ozon zeigen dessen Effektivität bei der Abscheidung von LiSixOy‐Filmen. Der ALD‐Prozess zeigt ein gesättigtes Wachstum pro Zyklus (engl. Growth per Cycle, GPC) von 0,95 Å. Die Zusammensetzung, analysiert mittels Rutherford‐Rückstreu‐Spektrometrie/Kernreaktionsanalyse (engl. Rutherford Backscattering Spectrometry/Nuclear Reaction Analysis, RBS/NRA), Röntgenphotoelektronenspektroskopie (engl. X‐ray Photoelectron Spectroscopy, XPS) und Glimmentladungsspektroskopie (engl. Glow Discharge Optical Emission Spectrometry, GD‐OES), bestätigt das Vorhandensein von Lithium und Silizium in den erwarteten Verhältnissen. Diese Arbeit stellt nicht nur einen neuen ALD‐Präkursor vor, sondern trägt auch zum Verständnis der Lithiumchemie bei und bietet Einblicke in die faszinierende Koordinationschemie und das thermische Verhalten von durch NHC‐Liganden stabilisierten Lithiumkomplexen.
KW - Atomlagenabscheidung
KW - N-heterozyklischer-Carben-(NHC)-stabilisierter Lithium-Präkursor
KW - Mononuklearer Li–Carben-Komplex
KW - Lithiumsilicat-Dünnfilme
KW - Filmanalytik/-Charakterisierung
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644045
DO - https://doi.org/10.1002/ange.202513066
SN - 0044-8249
N1 - Es gibt eine parallele Sprachausgabe (englisch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (English), a link is in the field related identifier
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64404
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunji Purayil, Sruthi Krishna
A1 - Röllig, Mathias
A1 - Hirsch, Philipp Daniel
A1 - Chaudhuri, Somsubhro
A1 - Lecompagnon, Julien
A1 - Strobach, L.
A1 - Ziegler, Mathias
T1 - PCA-enhanced Computational Thermography for the Non-destructive Investigation of the Historic Bücker Bü 181 Aircraft
N2 - Infrared thermography is a widely recognized non-destructive testing (NDT) method used in material research and defect detection across various industrial applications. Moreover, thermography plays a crucial role in preserving cultural heritage, including historical paintings and buildings. This study focuses on the application of thermography in inspecting the historic Bücker Bü 181 aircraft, which was used in Germany during World War II. Over time, the original appearance of aircraft has often been altered as part of preservation efforts, either before or during their time in museums, leading to deviations from their historically original state. Additionally, the operational history of such objects is frequently undocumented or entirely lost, making it difficult to understand the presence of artifacts and historically significant data. These factors present major challenges in cultural heritage preservation, and destructive methods cannot be used to investigate such invaluable objects.
Therefore, thermography is implemented as a non-destructive and contactless examination method. Active flash thermography combined with phase analysis is a powerful tool for evaluating multilayer systems. In this study, multiple layers of old paint on the object posed a challenge in assessing defect conditions and retrieving other critical information beneath the surface coatings. Nevertheless, pulse thermography not only demonstrated its capability to identify defects and markings in multilayered coatings but also provided insights into the internal structure and subsections of the investigated aircraft.
KW - Non-destructive Testing
KW - Infrared Thermography
KW - Defect Detection
KW - Cultural Heritage
KW - Multilayer Coatings
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645709
DO - https://doi.org/10.58286/31934
SN - 2941-4989
VL - 3
IS - 2
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-64570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hassenstein, Christian
A1 - Hirsch, Philipp Daniel
A1 - Wassermann, Jonas
A1 - Heckel, Thomas
T1 - Automated self-adjustment of array probe with a robotic ultrasonic test system
N2 - Ultrasonic testing of objects with complex geometries often requires the use of a robotic arm to position the probe perpendicular to the local surface. Using immersion makes it possible to test these objects with standard ultrasonic linear array probes. Here, the probe positions and orientations provided by the robot are used for merging the locally acquired image data into a 3D-reconstruction. The quality of this reconstruction is highly dependent on the alignment of the position of the physical probe with the position used in the digital model. For common industrial tools, the tool center point (TCP) is usually acquired using geometric features of the tools. However, for ultrasonic arrays in immersion, there is a water standoff between the probe and the test object, therefore the TCP is in free space in front of the array and cannot be acquired with the common method. To overcome this challenge, we propose a method that allows the robotic ultrasonic system to automatically self-adjust the position and orientation of the ultrasonic probe using a test block made of steel with defined geometric features as a target for referencing. For each of the six degrees of freedom, a scan and adjustment routine are established using the data based on the actual ultrasound characteristics of the probe. Given a coarse pre-definition of the tool position and the known target test block, minimal human interaction is required to supervise the adjustment method, leading to higher quality reconstructions than with manual adjustment.
T2 - 20th World Conference On Non-Destructive Testing (WCNDT 2024)
CY - Incheon, South Korea
DA - 27.05.2024
KW - Testing
KW - Automation
KW - NDT 4.0
KW - Robotics
KW - Ultrasonic
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616387
UR - https://www.ndt.net/search/docs.php3?id=30309
SN - 1435-4934
SP - 1
EP - 9
PB - NDT.net
AN - OPUS4-61638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kanaris, Orestis
A1 - Sobisch, Lydia-Yasmin
A1 - Gödt, Annett
A1 - Schreiber, Frank
A1 - Nordholt, Niclas
T1 - Consequences of benzalkonium chloride tolerance for selection dynamics and de novo resistance evolution driven by antibiotics
N2 - Biocides are used in large amounts in industrial, medical, and domestic settings. Benzalkonium chloride (BAC) is a commonly used biocide, for which previous research revealed that Escherichia coli can rapidly adapt to tolerate BAC-disinfection, with consequences for antibiotic susceptibility. However, the consequences of BAC tolerance for selection dynamics and resistance evolution to antibiotics remain unknown. Here, we investigated the effect of BAC tolerance in E. coli on its response upon challenge with different antibiotics. Competition assays showed that subinhibitory concentrations of ciprofloxacin—but not ampicillin, colistin and gentamicin—select for the BAC-tolerant strain over the BAC-sensitive ancestor at a minimal selective concentration of 0.0013–0.0022 µg/mL. In contrast, the BAC-sensitive ancestor was more likely to evolve resistance to ciprofloxacin, colistin and gentamicin than the BAC-tolerant strain when adapted to higher concentrations of antibiotics in a serial transfer laboratory evolution experiment. The observed difference in the evolvability of resistance to ciprofloxacin was partly explained by an epistatic interaction between the mutations conferring BAC tolerance and a knockout mutation in ompF encoding for the outer membrane porin F. Taken together, these findings suggest that BAC tolerance can be stabilized in environments containing low concentrations of ciprofloxacin, while it also constrains evolutionary pathways towards antibiotic resistance.
KW - AMR
KW - Resistance evolution
KW - Resistance selection
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653842
DO - https://doi.org/10.1038/s44259-025-00170-8
SN - 2731-8745
VL - 4
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65384
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lecompagnon, Julien
A1 - Ricci, M.
A1 - Laureti, S.
A1 - Ziegler, Mathias
ED - Maldague, X.
T1 - Practical study on the thermographic detectability of internal defects using temporally structured laser heating
N2 - Modern laser systems have proven to be highly versatile heat sources for active thermographic testing. Compared to more traditional light sources, e.g. flash or halogen lamps, their output power can be easily modulated at high rates, allowing a wide variety of complex excitations to be realized. Although their total optical output power can be theoretically scaled to arbitrary values, the maximum output power is practically limited by many factors: the maximum power that the sample under test can absorb without altering the lighted surface itself, the trade-off between irradiance and inspected area, the cost of the laser system, etc. Furthermore, when working with spatial modulator systems, the output power must be limited to avoid damaging such devices. Nevertheless, to guarantee a sufficient amount of heating even for highly thermally conductive materials and/or deeply buried defects, the heating times can be extended, e.g., either by using step heating, long pulse thermography, or by lock-in thermography with a continuously modulated heating. However, for all these approaches, the ranging capabilities of the thermographic defect detection are reduced due to the limited frequency content of the excitation.
To tackle this problem, i.e. to increase the excitation energy while preserving its frequency content, new approaches have been developed in the last two decades, among them the use of coded excitations in combination with pulse-compression, and the use of multiple lock-in analysis or a frequency modulated excitation signal. The challenges of such temporally structured heating techniques are manifold, for example, the DC component inherent in optical heating must be taken into account. In general, a wider frequency bandwidth or greater variability of the frequency components also means greater complexity for signal generation and data processing. In this paper, temporally structured excitation schemes with different degrees of complexity are compared on a high-power laser system.
T2 - 17th International Conference on Quantitative InfraRed Thermography 2024
CY - Zagreb, Croatia
DA - 01.07.2024
KW - Thermography
KW - Laser
KW - NDT
KW - Coded excitation
KW - Defect identification
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653790
DO - https://doi.org/10.21611/qirt-2024-077
SN - 2371-4085
SP - 1
EP - 9
PB - QIRT Council
AN - OPUS4-65379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hirsch, Philipp Daniel
A1 - Kunji Purayil, Sruthi Krishna
A1 - Lecompagnon, Julien
A1 - Pech May, Nelson Wilbur
A1 - Ziegler, Mathias
ED - Maldague, X.
T1 - Robotic-Assisted 3D Scanning and Laser Thermography for Crack Inspection on Complex Components
N2 - The integration of automation and robotics into non-destructive testing (NDT) marks a significant advancement in evaluating complex components. This paper introduces a novel approach using robotic-assisted laser thermography combined with automated 3D scanning to detect and analyze cracks in complex structures. The system uses an integrated line scanner with a robotic arm to capture high-resolution data, creating detailed 3D models for adaptive path planning and precise alignment correction. Laser thermography, based on localized heating and the "flying spot" approach, detects surfacenear cracks with high precision. Crack detection is achieved using the Canny algorithm optional on Fourier-transformed thermograms, offering robust results with minimal computation. This study highlights the potential of robotic-assisted 3D scanning and laser thermography as efficient and precise methods for crack inspection, advancing NDT technologies and ensuring the structural integrity of modern components.
T2 - 17th International Conference on Quantitative InfraRed Thermography 2024
CY - Zagreb, Croatia
DA - 01.07.2024
KW - Thermography
KW - Non-destructive testing
KW - Laser line
KW - Robotic arm
KW - Defect identification
KW - Crack detection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653809
DO - https://doi.org/10.21611/qirt-2024-078
SP - 1
EP - 8
PB - QIRT Council
AN - OPUS4-65380
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kunji Purayi, Sruthi Krishna
A1 - Hirsch, Philipp Daniel
A1 - Lecompagnon, Julien
T1 - Anisotropy investigation of a single crystal superalloy using laser-spot infrared thermography
N2 - Thermal property investigation of anisotropic materials such as single crystal superalloys are still in interest of practical and fundamental reasons but remains challenging using conventional testing methods. In this study, a single crystal superalloy is tested using laser-spot thermography, and its thermal anisotropy is investigated. Determining anisotropic thermal conductivity at microscopic scales is challenging, as it appears isotropic at the macroscopic scale. Infrared thermography is one of the best-known techniques for measuring material heat transfer properties and facilitating visualization of temperature distribution through the specimen. The proposed study uses the active thermography method of laser-spot infrared thermography, in which a laser spot is focused onto the sample surface and the thermal response is captured from the surface of the specimen with an infrared camera. A detailed analysis of temperature gradients and heat diffusion patterns aids in the measurement of thermal conductivity values along the sample's different crystallographic directions. The directional bonding characteristics and inherent crystallographic structure of the alloy account for the inplane thermal conductivities calculated from experimental thermal measurements. The laser-spot thermography method has proven to be an effective tool for mapping the material's thermal conductivity anisotropy with high sensitivity and high spatial and temporal resolution. The investigation into the anisotropy of the material provides an insight into heat flow in the structure and helps in optimizing the design and overall performance of the material system.
T2 - 17th International Conference on Quantitative InfraRed Thermography 2024
CY - Zagreb, Croatia
DA - 01.07.2025
KW - Infrared thermography
KW - Anisotropy
KW - Laser-spot thermography
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653877
DO - https://doi.org/10.21611/QIRT-2024-075
SP - 1
EP - 6
PB - QIRT Council
AN - OPUS4-65387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunji Purayil, Sruthi Krishna
A1 - Aroliveetil, S.
A1 - Chaturvedi, A.
A1 - Balasubramaniam, K.
T1 - Simulation-assisted multimodal deep learning (Sim-MDL) fusion models for the evaluation of thermal barrier coatings using infrared thermography and Terahertz imaging
N2 - Thermal Barrier Coatings (TBCs) are critical for high-temperature applications, such as gas turbines and aerospace engines, protecting metallic substrates from extreme thermal stress and degradation. Accurate evaluation of TBCs is essential to improve operational efficiency, optimize predictive maintenance strategies, and extend component life. Conventional non-destructive evaluation (NDE) techniques such as infrared thermography (IRT) and terahertz (THz) imaging have been widely used for TBC inspection with limitations when used independently, including sensitivity to surface conditions, limited penetration depth mainly in multi-layer coatings. This study proposes a novel framework called simulation-assisted multimodal deep learning (Sim-MDL) that combines IRT and THz data for a comprehensive evaluation of TBCs. To generalize the study to varying thermophysical properties of TBCs, the study uses simulation-generated data along with experimental data for training deep learning models. Two deep learning frameworks based on a 1D convolutional neural networks (CNN) and a long short-term memory (LSTM) with attention were developed for the multimodal feature fusion. The IR-THz fused frameworks enable simultaneous prediction of key TBC topcoat properties including thermal conductivity, heat capacity, topcoat thickness and refractive index. Experiments were conducted on four newly coated samples topcoat thicknesses ranging from 24 to 120 μm. An attention-based LSTM model trained on both simulation and experimental data shows high prediction accuracy with MAPE values ranging from 2.06% to 4.43% for thermal conductivity, 2.05% to 3.57% for heat capacity, 11.53% to 1.75% for topcoat thickness, and 0.27% to 1.05% for refractive index, respectively, for the topcoat layers of four samples. The proposed Sim-MDL framework outperformed single-modality and conventional parameter estimation methods in accuracy and robustness, highlighting the potential of multimodal data for automated analysis of TBC in industrial settings.
KW - Multimodal fusion
KW - Deep Learning
KW - Infrared Thermography
KW - Terahertz
KW - Thermal Barrier Coatings (TBC)
KW - Non-destructive Evaluation (NDE)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651747
DO - https://doi.org/10.1038/s41598-025-31783-8
SN - 2045-2322
VL - 16
SP - 1
EP - 33
PB - Springer Science and Business Media LLC
AN - OPUS4-65174
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Portarapillo, Maria
A1 - Di Benedetto, Almerinda
A1 - Spitzer, Stefan
T1 - Turbulence effect on the determination of powders safety characteristics — A review on the experimental findings and simulation approaches
N2 - Safety characteristics are widely used in the process industry to design facilities in a safe way. For powders, they are normally investigated under turbulent conditions inside a spherical test vessel, the so called 20L-sphere, to disperse the dust in air. This has been the target of many researchers to either investigate the turbulence that is present during the standardized test conditions, to compare it to quiescent conditions or to manipulate it for the comparison to other conditions. The approaches have been numerous and while the focus used to be on obtaining different experimental results it has shifted more and more to different kinds of simulations. This review gives an overview about different simulation approaches and how they can be compared. It is also an overview over the experimental findings and compares it to data obtained for three different dusts while changing the pre-ignition turbulence level in a very fine way.
KW - Explosion protection
KW - Dusts
KW - Pressure rise
KW - Ignition
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625216
DO - https://doi.org/10.1016/j.powtec.2025.120694
SN - 1873-328X
VL - 454
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-62521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
T1 - Error suppression in wavelength scanning coherent optical time domain reflectometry by polarization diversity detection
N2 - Wavelength scanning coherent optical time domain reflectometry (WS-COTDR) is a popular distributed fiber sensing technique that quantifies environmental changes based on the frequency shift of Rayleigh reflection spectra which are usually obtained by cross correlation. This method can cause large errors due to the spikes in the spectrum caused by the random interference of the Rayleigh backscattered light and the uncorrelated section in the reflection spectrum. Polarization diversity detection is applied to suppress this type of error. Two orthogonally polarized components of the Rayleigh backscattered light are detected in a single sensing system and processed separately by cross correlation. The correlation spectra of the two polarizations are averaged to determine the frequency shift, effectively mitigating the large error. Meanwhile, the polarization dependence helps avoid the large errors caused by Fresnel reflection and restrain null sensitivity positions, where the frequency shift is difficult to be determined due to the similarity of the spectra. The sensing performance improvement is experimentally validated, and the proposed system is tested in the field to monitor traffic along a busy street in Berlin, demonstrating its functionality and feasibility in practice.
KW - Traffic monitoring
KW - Coherent optical time domain reflectometry
KW - Distributed fiber sensing
KW - Polarization diversity detection
KW - Optical fiber sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630320
DO - https://doi.org/10.1016/j.measurement.2025.117733
SN - 1873-412X
VL - 253
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kosár, László
A1 - Szabová, Zuzana
A1 - Kuracina, Richard
A1 - Spitzer, Stefan
A1 - Mynarz, Miroslav
A1 - Filipi, Bohdan
T1 - Study of the Safety Characteristics of Different Types of Pepper Powder (Capsicum L.)
N2 - This research was aimed at comparing the fire characteristics of different types of pepper in the context of explosion prevention. The following characteristics were studied: explosion pressure Pmax and Kst at selected concentrations, ignition temperature of the deposited dust layer from the hot surface, and minimum ignition energy. The comparison of the chemical properties of the used types of pepper was performed using TG/DSC. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. Each sample reached the maximum value of the explosion pressure and rate of pressure rise at different concentrations. The volume of the explosion chamber used also influenced the explosion characteristics. It is a consequence of the fact that the explosion characteristics strongly depend on the mechanism of action of a particular igniter. The minimum effect on the safety characteristics was observed when measuring the minimum ignition energy and the minimum ignition temperature of the dust layer from the hot surface. The results of the measurements suggest that different types of peppers exhibit different explosion characteristics. This information should then be considered in explosion prevention.
KW - Dust explosions
KW - Pepper samples
KW - Explosion characteristics
KW - Explosion protection
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605965
DO - https://doi.org/10.3390/fire7070229
VL - 7
IS - 7
SP - 1
EP - 14
PB - MDPI AG
AN - OPUS4-60596
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Braymer, Joseph J.
A1 - Knauer, Lukas
A1 - Crack, Jason C.
A1 - Oltmanns, Jonathan
A1 - Heghmanns, Melanie
A1 - Soares, Jéssica C.
A1 - Le Brun, Nick E.
A1 - Schünemann, Volker
A1 - Kasanmascheff, Müge
T1 - Yeast [FeFe]-hydrogenase-like protein Nar1 binds a [2Fe–2S] cluster
N2 - Nar1 is an essential eukaryotic protein proposed to function as an iron–sulphur (Fe/S) cluster trafficking factor in the cytosolic iron–sulphur protein assembly (CIA) machinery. However, such a role has remained unclear due to difficulties in purifying adequate amounts of cofactor-bound protein. The [FeFe]-hydrogenase-like protein has two conserved binding sites for [4Fe–4S] clusters but does not show hydrogenase activity in vivo due to the lack of an active site [2Fe]H cofactor. Here, we report a new preparation procedure for Nar1 that facilitated studies by UV-vis, EPR, and Mössbauer spectroscopies, along with native mass spectrometry. Nar1 recombinantly produced in E. coli contained a [4Fe–4S] cluster, bound presumably at site 1, along with an unexpected [2Fe–2S] cluster bound at an unknown site. Fe/S reconstitution reactions installed a second [4Fe–4S] cluster at site 2, leading to protein with up to three Fe/S cofactors. It is proposed that the [2Fe–2S] cluster occupies a cavity in Nar1 that is filled by the [2Fe]H cofactor in [FeFe]-hydrogenases. Strikingly, two of the Fe/S clusters were rapidly destroyed by molecular oxygen, linking Nar1 oxygen sensitivity in vitro to phenotypes observed previously in vivo. Our biochemical results, therefore, validate a direct link between cellular oxygen concentrations and the functioning of the CIA pathway. These advances also now allow for the pursuit of in vitro Fe/S cluster transfer assays, which will shed light on Fe/S trafficking and insertion by CIA components.
KW - Biocorrosion
KW - Hydrogenases
KW - Metalloprotein
KW - Yeast
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649463
DO - https://doi.org/10.1039/D5SC04860E
SN - 2041-6520
VL - 17
IS - 1
SP - 373
EP - 380
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64946
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schönsee, Eric
A1 - Hüsken, Götz
A1 - Kocherla, Amarteja
A1 - Strangfeld, Christoph
T1 - Influences of Surface Properties on the Reflection Intensity - Towards in Situ Monitoring During Early Age Hydration of CEM I
N2 - Interlayer bonding in 3D concrete printing is influenced by the hydration progress and surface moisture of the previously printed layer. For effective quality control, continuous in situ monitoring of interlayer surface properties is required. This study investigated reflection intensity as a method for in situ measurements during the hydration of CEM I mixtures with varying retarder contents. Additional factors influencing the reflection intensity are also examined. Two laser line scanners with different wavelengths were used to track hydration over 72 h. Vicat tests and isothermal calorimetry served as reference methods. Across all the mixtures, the reflection intensity exhibited a repeatable pattern with five different stages. A sharp increase in intensity during the third stage was consistent with the acceleration period of hydration. These findings suggest that reflection intensity measurements could serve as a promising tool for evaluating interlayer bonding in 3D concrete printing.
KW - In situ hydration monitoring
KW - Cement
KW - Optical methods
KW - Reflection intensity
KW - Additive manufacturing
KW - Isothermal calorimetry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653430
DO - https://doi.org/10.1007/s10921-025-01326-2
SN - 1573-4862
VL - 45
IS - 1
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-65343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Königsbauer, Korbinian
A1 - Hicke, Konstantin
T1 - Improved phase retrieval method for system simplification or fading suppression in interferometer-based φOTDR systems
N2 - Phase sensitive optical time domain reflectometry (φOTDR) systems based on different types of interferometers for phase retrieval typically require two or three photodetectors to record the outputs from the interferometer. A novel signal processing principle is proposed for phase retrieval by taking the difference between two outputs as the quadrature component and reconstructing the in-phase component via Hilbert transformation of the Q component for IQ demodulation. Thus, only one balanced photodetector or two standard photodetectors are need, reducing system complexity and data volume. This principle can also be used to suppress fading effect for the traditional three-detector φOTDR systems by selecting optimal phases across detector pairs. Experiments with a φOTDR systems based on an imbalanced Mach-Zehnder interferometer validate the feasibility of this method and demonstrate a high fading suppression of about 90%.
KW - Phase retrieval
KW - Distributed fiber sensing
KW - Structural health monitoring
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652630
DO - https://doi.org/10.1364/OE.580984
SN - 1094-4087
VL - 33
IS - 26
SP - 54733
EP - 54746
PB - Optica Publishing Group
AN - OPUS4-65263
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saleh, Maysoon I.
A1 - Rühle, Bastian
A1 - Wang, Shu
A1 - Radnik, Jörg
A1 - You, Yi
A1 - Resch-Genger, Ute
T1 - Assessing the protective effects of different surface coatings on NaYF4:YB3+, Er3+, upconverting nanoparticles in buffer and DMEM
N2 - We studied the dissolution behavior of β NaYF4:Yb(20%), Er(2%) UCNP of two different sizes in biologically relevant media i.e., water (neutral pH), phosphate buffered saline (PBS), and Dulbecco’s modified Eagle medium (DMEM) at different temperatures and particle concentrations. Special emphasis was dedicated to assess the influence of different surface functionalizations, particularly the potential of mesoporous and microporous silica shells of different thicknesses for UCNP stabilization and protection. Dissolution was quantified electrochemically using a fluoride ion selective electrode (ISE) and by inductively coupled plasma optical emission spectrometry (ICP OES). In addition, dissolution was monitored fluorometrically. These experiments revealed that a thick microporous silica shell drastically decreased dissolution. Our results also underline the critical influence of the chemical composition of the aqueous environment on UCNP dissolution. In DMEM, we observed the formation of a layer of adsorbed molecules on the UCNP surface that protected the UCNP from dissolution and enhanced their fluorescence. Examination of this layer by X ray photoelectron spectroscopy (XPS) and mass spectrometry (MS) suggested that mainly phenylalanine, lysine, and glucose are adsorbed from DMEM. These findings should be considered in the future for cellular toxicity studies with UCNP and other nanoparticles and the design of new biocompatible surface coatings.
KW - Fluorescence
KW - Lifetime
KW - Method
KW - Quantification
KW - Stability
KW - Coating
KW - Surface chemistry
KW - Lanthanide
KW - Fluoride
KW - Electrochemistry
KW - ICP-OES
KW - Upconversion
KW - Nano
KW - Particle
KW - Aging
KW - Quality assurance
KW - Mass spectrometry
KW - XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515984
DO - https://doi.org/10.1038/s41598-020-76116-z
SN - 2045-2322
VL - 10
IS - 1
SP - 19318-1
EP - 19318-11
PB - Springer Nature
CY - London
AN - OPUS4-51598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Farhan, Muhammad
A1 - Schneider, Ronald
A1 - Thöns, Sebastian
A1 - Gündel, M.
T1 - Probabilistic cost modeling as a basis for optimizing inspection and maintenance of turbine support structures in offshore wind farms
N2 - The operational management of offshore wind farms includes inspection and maintenance (I&M) of the wind turbine support structures. These activities are complex and influenced by numerous uncertain factors that affect their costs. The uncertainty in the I&M costs should be considered in decision value analyses performed to optimize I&M strategies for the turbine support structures. In this paper, we formulate a probabilistic parametric model to describe I&M costs for the common case in which a wind farm is serviced and maintained using a workboat-based strategy. The model is developed based on (a) interviews with a wind farm operator, engineering consultants, and operation and maintenance engineers, as well as (b) scientific literature. Our methodology involves deriving the probabilistic models of the cost model parameters based on intervals representing a subjective expert opinion on the foreseeable ranges of the parameter values. The probabilistic cost model is applied to evaluate the total I&M costs, and a sensitivity analysis is conducted to identify the main cost drivers. The model can be utilized to optimize I&M strategies at the component, structural system, and wind farm level. To illustrate its potential use, we apply it in a numerical study in which we optimize I&M strategies at the structural system level and identify and demonstrate a simplified approach of capturing uncertain I&M costs in the optimization. The simplified approach is generalized and made available for maintenance cost optimization of offshore wind turbine structures.
KW - Inspection
KW - Maintenance
KW - Turbine support structures
KW - Offshore wind
KW - Costs
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626144
DO - https://doi.org/10.5194/wes-10-461-2025
SN - 2366-7443
SN - 2366-7451
VL - 10
IS - 2
SP - 461
EP - 481
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-62614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spitzer, Stefan
A1 - Reitmeier, Fabian
A1 - Danzi, Enrico
A1 - Janovsky, Bretislav
A1 - Paul, Michael
T1 - The Exploding Wire: A novel ignition source for the determination of safety characteristics of dusts and hybrid mixtures
N2 - For the determination of safety characteristics of dusts there are mainly chemical igniters in use. Especially for the maximum explosion pressure and the maximum rate of pressure rise there is no standard with another ignition source. The chemical igniters have the disadvantage of being very hard to obtain in most countries and they are even illegal in some. This leads to the fact, that those countries are not able to investigate the safety characteristics or only with a high effort by sending dust samples to facilities outside the country. This article presents a novel ignition source and describes how to build it. It is also the first step to place this ignition source into the dust standards in the future.
KW - Explosion protection
KW - Dust explosions
KW - Pressure rise
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645209
DO - https://doi.org/10.1016/j.elstat.2025.104188
SN - 0304-3886
VL - 138
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-64520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spitzer, Stefan
A1 - Askar, Enis
A1 - Hecht, Kristin
A1 - Gabel, D.
A1 - Zakel, S.
A1 - Krietsch, Arne
T1 - Requirements for a Hybrid Dust-Gas-Standard: Influence of the Mixing Procedure on Safety Characteristics of Hybrid Mixtures
N2 - While developing a standard for the determination of safety characteristics for hybrid mixtures the authors discovered, that, beside the ignition source, the mixing procedure is the main difference between the single-phase standards for dusts and gases. The preparation of hybrid mixtures containing a flammable gas and a flammable dust in the 20 L-sphere can be realized in different ways. Either the flammable gas is filled only in the sphere or only in the dust container or in both. In previous works, almost always the first method is applied, without giving any information on the accuracy of the gas mixtures. In this work the accuracy of the gas mixtures and the results of the tests applying two methods of mixing were studied. No significant influence of the mixing method itself on the safety characteristics explosion pressure pex and the normalized rate of pressure rise (K-value) was found. Obviously, homogenization of the gas mixtures can be obtained sufficiently by the turbulence that is caused during the injection from the dust container into the explosion chamber within a short time. However, the mixing procedure has a great influence on the accuracy of the gas amount of the mixtures obtained. Without modifying the 20 L-sphere by installing precise pressure sensors, assuring its tightness and performing gas analysis, it must be expected, that the accuracy of the gas mixtures is very low. This has a significant influence on the measured safety characteristics and may lead to unsafe facilities or unnecessary expensive safety measures.
KW - Hybrid mixtures
KW - 20 L-sphere
KW - Pre-ignition pressure rise
KW - Post-injection pressure drop
KW - Safety characteristics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554610
DO - https://doi.org/10.3390/fire5040113
VL - 5
IS - 4
SP - 1
EP - 10
PB - MDPI
CY - Basel
AN - OPUS4-55461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spitzer, Stefan
A1 - Askar, Enis
A1 - Benke, Alexander
A1 - Janovsky, B.
A1 - Krause, U.
A1 - Krietsch, Arne
T1 - Influence of pre-ignition pressure rise on safety characteristics of dusts and hybrid mixtures
N2 - For the determination of the safety characteristics of dusts it is necessary to disperse the dust in the oxidating atmosphere (usually air). In the standard procedures for dusts this is realized by a partially evacuated explosion vessel (20L-sphere) in which the dust gets injected from a dust chamber pressurized with air. Shortly after that injection (60 ms) the dust cloud gets ignited under turbulent conditions, that are otherwise seen as almost ambient with 20 ◦C and about 1 bar (abs). While there has been a lot of research about the influence of the ignition delay time and the level of turbulence in the recent years little attention was paid to the pre–ignition pressure rise and the allowed variations in the standards. In the following work we showed that the allowed ranges for the pressures in the different dust standards influence the safety characteristics of dust alone severely.
Even though hybrid mixtures are an emerging risk problem in an interconnected industry there is no standard for the determination of their safety characteristics. In this work it is shown that especially for the preparation of hybrid mixtures of flammable dust and gas the pressures after injection of the dust and the mixing procedure have a large influence on the composition of the tested mixtures and therefore on the safety characteristics.
Considering both effects, wrong concentration of gas and wrong initial pressure, the discrepancy of safety characteristics from different facilities will be too big to applicable. The methods to overcome these weaknesses are also presented.
KW - Hybrid mixtures
KW - 20L-sphere
KW - Pre-ignition pressure rise
KW - Post-injection pressure drop
KW - Safety characteristics
KW - Mixing procedure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537358
DO - https://doi.org/10.1016/j.fuel.2021.122495
VL - 311
SP - 122495
PB - Elsevier Ltd.
CY - Niederlande
AN - OPUS4-53735
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spitzer, Stefan
A1 - Askar, Enis
A1 - Krietsch, Arne
A1 - Schröder, Volkmar
T1 - Comparative study on standardized ignition sources used for explosion testing
N2 - For the determination of safety characteristics of gases, vapors and dusts different types of ignition sources are used in international standards and guidelines. Table 1 compares technical relevant ignition sources with their main features. The paper presents test results of a comparative calorimetric and visual study between four different types of ignition sources. The ignition procedures were analyzed visually with a high-speed camera and electric recordings. In addition to that, the influence of the electrode-orientation, -distance as well as ignition energy on the reproducibility of the exploding wire igniter was tested.
The exploding wire is already in use for standardized determination of safety characteristics of gases, first tests on the suitability of the exploding wire igniter for dust testing have been carried out by Scheid et al. Using the exploding wire, the ignition energy can be varied from 2 to 10 000 J (2 x 5 000 J) and thus it could be used for gases, vapors, dusts and hybrid mixtures. Moreover it can be used at high initial pressures and it is the only ignition source with an easily measurable ignition energy release. Furthermore, it does not introduce another chemical reaction into the system.
Finally, a proposal for a standard ignition source for explosion tests on hybrid mixtures is derived from the test results.
T2 - 13th International Symposium on Hazards, Prevention and Mitigation of Industrial Explosions
CY - Online meeting
DA - 27.07.2020
KW - Ignition source
KW - Exploding Wire
KW - Hybrid mixtures
KW - Safety characteristics determination
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517908
UR - https://oar.ptb.de/files/download/5f3e662f4c93901010006dbf
DO - https://doi.org/10.7795/810.20200724
VL - 13
SP - 864
EP - 875
PB - PTB Physikalisch-Technische Bundesanstalt Braunschweig
AN - OPUS4-51790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spitzer, Stefan
A1 - Riesner, G.
A1 - Zakel, S.
A1 - Schierding, C.
T1 - A New Ignition Source for the Determination of Safety Characteristics of Gases
N2 - Safety characteristics are used to keep processes, including flammable gases, vapors, and combustible dusts, safe. In the standards for the determination of safety characteristics of gases and vapors, the induction spark is commonly used. However, classic transformers are hard to obtain, and replacement with new electronic transformers is not explicitly allowed in the standards. This article presents the investigation of five gases that are normally used to calibrate devices for the determination of safety characteristics, the maximum experimental safe gap (MESG), with an electronic transformer, and the values are compared to the ones that are obtained with the standard transformer. Additionally, calorimetric measurements on the net energy of both ignition sources were performed as well as open-circuit voltage measurements. It is concluded that the classic type of transformer can be replaced by the new type obtaining the same results for the MESG and introducing the same amount of energy into the system.
KW - Safety characteristics
KW - Ignition sources
KW - MESG
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578528
DO - https://doi.org/10.3390/gases3030007
VL - 3
IS - 3
SP - 106
EP - 111
PB - MDPI
CY - Basel
AN - OPUS4-57852
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cairns, Warren R. L.
A1 - Braysher, Emma C.
A1 - Butler, Owen T.
A1 - Cavoura, Olga
A1 - Davidson, Christine M.
A1 - Todoli Torro, Jose Luis
A1 - von der Au, Marcus
T1 - Atomic spectrometry update: review of advances in environmental analysis
N2 - This review covers advances in the analysis of air, water, plants, soils and geological materials by a range of atomic spectrometric techniques including atomic emission, absorption, fluorescence and mass spectrometry.
KW - Environmental analysis
KW - Review
KW - Trend Article
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653977
DO - https://doi.org/10.1039/D5JA90058A
SN - 0267-9477
VL - 41
IS - 1
SP - 16
EP - 70
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Onyenso, Gabriel
A1 - AI-Zawity, Jiwar
A1 - Farahbakhsh, Nastaran
A1 - Schardt, Annika
A1 - Yadigarli, Aydan
A1 - Vakamulla Raghu, Swathi Naidu
A1 - Engelhard, Carsten
A1 - Müller, Mareike
A1 - Schönherr, Holger
A1 - Killian, Manuela S.
T1 - Novel Ag-modified zirconia nanomaterials with antibacterial activity
N2 - The outcome of an implant procedure largely depends on the implant's surface properties. Biomaterials are now designed to have surfaces with multifunctionality, such as favorable tissue integration and the ability to combat bacterial adhesion and colonization. Herein, we report on a simple approach to improve the antibacterial properties of zirconia nanotubes (ZrNTs) coatings by decorating with silver nanoparticles (AgNP), achieved through electrochemical anodization of a zirconium–silver alloy (Zr–Ag). The AgNPs were shown to partially consist of Ag2O, potentially enhancing the availability of Ag+ ions for antibacterial activity. The modified ZrNTs were characterized using SEM, EDS, ToF-SIMS, and XPS to determine their structural morphology and chemical composition, and were further subjected to antibacterial testing. The silver and zirconium ion release behavior was monitored via ICP-MS. ZrNTs decorated with AgNP exhibit strong antimicrobial activity (>99% bacterial killing) against both S. aureus and E. coli. Antimicrobial tests indicate that the antibacterial activity against the Gram-positive pathogen S. aureus was improved by a factor of 100 compared to unmodified ZrNTs, while unmodified ZrNTs already showed a comparable reduction of viable Gram-negative E. coli. This strategy illustrates a straightforward and effective modification that optimizes the interface between the host environment and the biomaterial surface to meet the very important criteria of biocompatibility and active antibacterial response.
KW - Mass Spectrometry
KW - Nanoparticles
KW - Advanced Materials
KW - ICP-MS
KW - Antimicrobial material
KW - ToF-SIMS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653990
DO - https://doi.org/10.1039/d5ra07099f
SN - 2046-2069
VL - 16
IS - 3
SP - 2286
EP - 2297
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rossi, Andrea
A1 - Alladio, Eugenio
A1 - Drobne, Damjana
A1 - Hodoroaba, Vasile-Dan
A1 - Jurkschat, Kerstin
A1 - Kononenko, Veno
A1 - Madbouly, Loay Akmal
A1 - Mrkwitschka, Paul
A1 - Novak, Sara
A1 - Radnik, Jörg
A1 - Saje, Špela
A1 - Santalucia, Rosangela
A1 - Sordello, Fabrizio
A1 - Pellegrino, Francesco
T1 - Development of a one-pot synthesis of rGO in water by optimizing Tour’s method parameters
N2 - Since its first synthesis in 2004, graphene has been widely studied and several different synthesis methods has been developed. Solvent exfoliation of graphite and the reduction of graphene oxide previously obtained through graphite oxidation are the most employed. In this work, we exploited synthesis conditions of a method usually employed for obtaining graphene oxide (the Tour’s method) for directly obtaining a very poorly oxidised material with characteristics like reduced graphene oxide. For the first time, a one-pot synthesis of reduced graphene oxide (rGO) is reported avoiding the use of a post-synthesis chemical or thermal reduction of the graphene oxide that requires further reagents, heat and time.
KW - Graphene
KW - 2D-materials
KW - Tour's method
KW - rGO
KW - One-pot synthesis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611827
DO - https://doi.org/10.1038/s41598-024-73606-2
SN - 2045-2322
VL - 14
SP - 1
EP - 10
PB - Springer Nature
CY - London
AN - OPUS4-61182
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vogel, Amelie
A1 - Tentschert, Jutta
A1 - Pieters, Raymond
A1 - Bennet, Francesca
A1 - Dirven, Hubert
A1 - van den Berg, Annemijne
A1 - Lenssen, Esther
A1 - Rietdijk, Maartje
A1 - Broßell, Dirk
A1 - Haase, Andrea
T1 - Towards a risk assessment framework for micro- and nanoplastic particles for human health
N2 - Background
Human exposure to micro- and nanoplastic particles (MNPs) is inevitable but human health risk assessment remains challenging for several reasons. MNPs are complex mixtures of particles derived from different polymer types, which may contain plenty of additives and/or contaminants. MNPs cover broad size distributions and often have irregular shapes and morphologies. Moreover, several of their properties change over time due to aging/ weathering. Case-by-case assessment of each MNP type does not seem feasible, more straightforward methodologies are needed. However, conceptual approaches for human health risk assessment are rare, reliable methods for exposure and hazard assessment are largely missing, and meaningful data is scarce.
Methods
Here we reviewed the state-of-the-art concerning risk assessment of chemicals with a specific focus on polymers as well as on (nano-)particles and fibres. For this purpose, we broadly screened relevant knowledge including guidance documents, standards, scientific publications, publicly available reports. We identified several suitable concepts such as: (i) polymers of low concern (PLC), (ii) poorly soluble low toxicity particles (PSLT) and (iii) fibre pathogenicity paradigm (FPP). We also aimed to identify promising methods, which may serve as a reasonable starting point for a test strategy.
Results and conclusion
Here, we propose a state-of-the-art modular risk assessment framework for MNPs, focusing primarily on inhalation as a key exposure route for humans that combines several integrated approaches to testing and assessment (IATAs). The framework starts with basic physicochemical characterisation (step 1), followed by assessing the potential for inhalative exposure (step 2) and includes several modules for toxicological assessment (step 3). We provide guidance on how to apply the framework and suggest suitable methods for characterization of physicochemical properties, exposure and hazard assessment. We put special emphasis on new approach methodologies (NAMs) and included grouping, where adequate. The framework has been improved in several iterative cycles by taking into account expert feedback and is currently being tested in several case studies. Overall, it can be regarded as an important step forward to tackle human health risk assessment.
KW - Microplastics
KW - Nanoplastics
KW - Human health
KW - Risk assessment
KW - Integrated approaches to testing and assessment (IATAs)
KW - Polymers of low concern (PLC)
KW - Poorly soluble low toxicity particles (PSLT)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623790
DO - https://doi.org/10.1186/s12989-024-00602-9
SN - 1743-8977
VL - 21
IS - 1
SP - 1
EP - 21
PB - Springer Science and Business Media LLC
AN - OPUS4-62379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vega Puga, E.
A1 - Wachtendorf, Volker
A1 - Kömmling, Anja
A1 - Brendelberger, S.
A1 - Jaunich, Matthias
A1 - Sattler, C.
T1 - Lifetime prediction and degradation assessment of FKM and FFKM O-rings under high temperature thermo-oxidative ageing
N2 - To support the development of solar reactor technologies for hydrogen production, this study investigates the thermo-oxidative degradation mechanisms of fluorinated elastomers and predicts their lifetimes at high temperatures (200–300 ◦C) consistent with the application requirements. An accelerated ageing programme is conducted with FKM and FFKM O-rings and flat samples for up to 21 days. Optical microscopy is used to analyse the exposed seals’ morphological changes, while IR microscopy is utilised to investigate the underlying chemical degradation mechanisms of both elastomers. Findings suggest that FKM’s degradation arises from dehydrofluorination of the polymer, followed by chain scission and backbone cleavage as a result of the oxidation of newly formed C=C double bonds. FFKM’s degradation is primarily associated with chain scission, but there is also indication that post-curing processes may occur during material ageing. Furthermore, hardness, equilibrium compression set (CS), continuous compression stress relaxation (CSR) and leakage rate tests are used to evaluate changes in the mechanical properties and sealing performance of the elastomers. Equilibrium CS data is extrapolated using time-temperature shifts (TTS) and used to derive an end-of-life criterion of 75 % equilibrium CS, which correlates to leakage rates higher than a predetermined threshold. Service lifetime predictions of FKM and FFKM O-rings at several temperatures are performed and a seal operating temperature of 200 ◦C is suggested, which ensures reasonable O-ring replacement intervals of more than half a year in the solar reactor for both considered materials.
KW - Fluoroelastomer
KW - Perfluoroelastomer
KW - Thermo-oxidative ageing
KW - Lifetime prediction
KW - Compression set
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630112
DO - https://doi.org/10.1016/j.polymertesting.2025.108820
SN - 1873-2348
VL - 147
SP - 1
EP - 17
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chemello, Giovanni
A1 - Despotelis, Konstantinos
A1 - Paton, Keith
A1 - Clifford, Charles A
A1 - Pollard, Andrew
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Approaches for the measurement of lateral dimensions of graphene oxide flakes using scanning electron microscopy
N2 - There is a practical need, especially from the industrial community, to accurately measure the size and shape of graphene oxide (GO) flakes of commercial origin, in a reliable, simple, and unambiguous way. The sample preparation is a decisive step to obtain a homogeneous distribution of flakes on a substrate, which is suitable for image analysis. A certain level of inhomogeneity was still found but could be accepted for the purpose of this lateral size measurement study. A measurement procedure for Scanning Electron Microscopy (SEM) including sample preparation, measurement, image analysis and reporting was developed and validated to be applied for the lateral size analysis of “real-world” 2D flakes. Samples were produced for analysis by drop casting GO dispersions onto Si/SiO2 substrates. After SEM imaging, the images were analysed using two approaches to derive size and shape parameters. The influence of different operators has been evaluated. A maximum difference of 10% for the size descriptor and 2% for shape descriptor was found for both image analysis approaches when different samples of the same source material are measured and analysed by the same operator, hence indicating variability caused by sample preparation and analysing different sample areas. When different laboratories/operators perform the image analysis on exactly the same images and same flakes, the deviation found for the size descriptor is 2% and 4.6% corresponding to the two approaches applied, while no difference in the shape descriptor is observed.
KW - Graphene oxide
KW - SEM
KW - Lateral dimension
KW - Standardisation
KW - Imaging
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625070
DO - https://doi.org/10.1088/2632-959X/adae28
VL - 6
IS - 1
SP - 1
EP - 11
PB - IOP Publishing
AN - OPUS4-62507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madbouly, Loay Akmal
A1 - Mrkwitschka, Paul
A1 - Stockmann, Jörg Manfred
A1 - Jones, Elliot
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Comparative Elemental Analysis of Commercial Functionalized Graphene Nanoplatelets Along the Production Chain With X‐Ray Photoelectron and Energy‐Dispersive X‐Ray Spectroscopy
N2 - Graphene has been commercialized for over a decade, primarily in the form of suspensions and inks. In this study, we investigate the properties of graphene nanoplatelets (GNPs) and their functionalized derivatives, incorporating fluorine or nitrogen as functional groups (FG). The analysis was conducted on three forms, that is, powders, suspensions, and inks, using X‐ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) with energy‐dispersive X‐ray spectroscopy (EDX). The objective of this work is to establish a rapid and comprehensive systematic approach for elemental analysis of commercial functionalized graphene, which can be used for quality control. Functionalization is employed to tailor the material's physical and chemical properties. In our study, graphene samples, functionalized with fluorine or ammonia in a plasma reactor, were investigated. Both XPS and EDX were applicable for all three forms and showed, in general, similar trends between the three forms, so that both XPS and EDX can be used for quality control of GNPs along the production chain.
KW - Commercial graphene
KW - Functionalized graphene
KW - Graphene inks
KW - SEM/EDS
KW - XPS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625752
DO - https://doi.org/10.1002/sia.7386
SN - 1096-9918
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-62575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - John, Elisabeth
A1 - Weise, Matthias
A1 - Radnik, Jörg
A1 - Stockmann, Jörg Manfred
A1 - Lange, Thorid
A1 - Sahre, Mario
A1 - Hodoroaba, Vasile-Dan
T1 - Towards a New Reference Material—Analytical Challenges in Examining High-Entropy Alloy Thin Films
N2 - A new high-entropy alloy (HEA) consisting of titanium, chromium, manganese, iron, and nickel was deposited as a thin-film on silicon substrates using magnetron sputtering from a novel segmented target composed of metal stripes. This material was explored with the goal to create a new reference material for surface analysis and evaluation of complex composite materials. The film's morphology was initially characterized by scanning electron microscopy (SEM), followed by crystallographic analysis using X-ray diffraction (XRD) and selected area electron diffraction (SAED). The two-dimensional compositional homogeneity was assessed using a combination of scanning and transmission electron microscopy (TEM) with energy-dispersive spectroscopy (EDS), X-ray fluorescence (XRF), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and X-ray photoelectron spectroscopy (XPS). The in-depth chemical composition was further analysed using ToF-SIMS and Auger electron spectroscopy (AES). Our findings demonstrate that it is possible to produce thin HEA films with a homogeneous in-depth composition from a segmented target. Notably, despite the fixed composition of the target, we were able to vary the HEA's composition by exploiting inhomogeneities within the magnetrons sputter plasma. Additionally, we successfully created HEA films with significant compositional gradients.
T2 - ECASIA
CY - Gothenburg, Sweden
DA - 10.06.2024
KW - Reference material
KW - High-entropy alloy
KW - Thin-films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625777
DO - https://doi.org/10.1002/sia.7387
SN - 1096-9918
SP - 1
EP - 8
PB - Wiley
AN - OPUS4-62577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chahal, Shweta
A1 - Xiao, Boyu
A1 - Grant, Jessica
A1 - Furniss, David
A1 - Farries, Mark
A1 - Phang, Sendy
A1 - Neate, Nigel
A1 - Robertson, Lorelei
A1 - Roe, Martin
A1 - Barney, Emma
A1 - Seddon, Angela B.
T1 - Ce3+-doped chalcogenide glass fibre for laser beyond 4 microns wavelength: Glass material-integrity
N2 - The 4-μm wavelength barrier encountered for mid-infrared fibre lasing based on heavy metal fluoride glasses has been overcome. We reported, in 2021, the first continuous wave, mid-infrared fibre laser operating beyond 4 μm at room temperature in a fibre with a Ce3+-doped selenide-chalcogenide core. Defects, such as crystallites in the core glass, could cause unwanted light-scattering, diminishing fibre laser efficiency. It is important to identify such optical loss mechanisms and eradicate them. Here, we report on investigating the material nano-structure of a chalcogenide-glass lasing fibre which exhibits 7 mW laser power output; the fibre has a Ce3+-doped core (8.5 μm diameter), concentrically surrounded by an inner- and outer-cladding, where both cladding-glasses are nominally the same composition. High resolution transmission electron microscopy and electron diffraction show that the core, inner-cladding and outer-cladding of the lasing fibre are internally nano-crystallite-free and amorphous. However, the external outer surface of the last 10 m of fibre drawn, of the total 100 m, contains monoclinic GeSe2 crystallites adjacent to discrete, small (<0.5 mm) wrinkled defects. The final length of fibre is drawn from the final part of the glass fibreoptic preform. The glass preform has as its outermost component an extruded chalcogenide glass tube. It is the last part of the tube which spends the longest time at high temperature inside the extruder during tube manufacture, encouraging heterogeneous nucleation at the tube outer-surface in contact with the extruder. These heterogeneous nuclei subsequently nucleate crystal growth during fibre-drawing in the outermost fibre surface.
KW - Optical glass
KW - Photonics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653371
DO - https://doi.org/10.1016/j.optmat.2025.117219
SN - 0925-3467
VL - 166
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65337
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sano, Silvia Di
A1 - Costa, Giancarlo
A1 - Giordano, Pier Francesco
A1 - Pregnolato, Maria
A1 - Limongelli, Maria Pina
T1 - Multi‐risk assessment for bridges: The application of the Italian Guidelines
N2 - Bridges are essential elements in the built environment since they underpin the functioning of transportation systems. Nevertheless, they are vulnerable due to aggressive environment, demand beyond the design level, and other contingencies such as extreme events. The management of bridges represents a significant challenge for improving transport performance and ensure the safety of users. In Italy, bridge management is addressed by the recent “Guidelines for risk classification and management, safety evaluation and monitoring of existing bridges” which were issued by the Italian Ministry for Public Work in 2020. The guidelines propose an operational approach with distinctive characteristics: (i) risk‐based, i.e., based on the typical parameters of hazard, vulnerability, and exposure; (ii) multi‐level, i.e., they include six assessment levels (0‐5) of increasing complexity; and (iii) multi‐risk, i.e., they assess structural/foundation, seismic, hydrological and landslide risk. This paper presents a general overview of the 2020 Italian Guidelines and their application to a selected case study. Lessons from the application to the case study are drafted and possible criticalities highlighted.
KW - Bridge management
KW - Infrastructures
KW - Italian guidelines
KW - Structural safety
KW - Risk assessment
KW - Risk classification
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653392
DO - https://doi.org/10.1002/cepa.2046
SN - 2509-7075
VL - 6
IS - 5
SP - 772
EP - 779
PB - Wiley
CY - Berlin
AN - OPUS4-65339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dumit, Verónica I.
A1 - Furxhi, Irini
A1 - Nymark, Penny
A1 - Afantitis, Antreas
A1 - Ammar, Ammar
A1 - Amorim, Monica J. B.
A1 - Antunes, Dalila
A1 - Avramova, Svetlana
A1 - Battistelli, Chiara L.
A1 - Basei, Gianpietro
A1 - Bossa, Cecilia
A1 - Cimpan, Emil
A1 - Cimpan, Mihaela Roxana
A1 - Ciornii, Dmitri
A1 - Costa, Anna
A1 - Delpivo, Camilla
A1 - Dusinska, Maria
A1 - Fonseca, Ana Sofia
A1 - Friedrichs, Steffi
A1 - Hodoroaba, Vasile-Dan
A1 - Hristozov, Danail
A1 - Isigonis, Panagiotis
A1 - Jeliazkova, Nina
A1 - Kochev, Nikolay
A1 - Kranjc, Eva
A1 - Maier, Dieter
A1 - Melagraki, Georgia
A1 - Papadiamantis, Anastasios G.
A1 - Puzyn, Tomasz
A1 - Rauscher, Hubert
A1 - Reilly, Katie
A1 - Jiménez, Araceli Sánchez
A1 - Scott‐Fordsmand, Janeck J.
A1 - Shandilya, Neeraj
A1 - Shin, Hyun Kil
A1 - Tancheva, Gergana
A1 - van Rijn, Jeaphianne P. M.
A1 - Willighagen, Egon L.
A1 - Wyrzykowska, Ewelina
A1 - Bakker, Martine I.
A1 - Drobne, Damjana
A1 - Exner, Thomas E.
A1 - Himly, Martin
A1 - Lynch, Iseult
T1 - Challenges and Future Directions in Assessing the Quality and Completeness of Advanced Materials Safety Data for Re‐Usability: A Position Paper From the Nanosafety Community
N2 - Ensuring data quality, completeness, and interoperability is crucial for progressing safety research, Safe‐and‐Sustainable‐by‐Design approaches, and regulatory approval of nanoscale and advanced materials. While the FAIR (Findable, Accessible, Interoperable, and Re‐usable) principles aim to promote data re‐use, they do not address data quality, essential for data re‐use for advancing sustainable and safe innovation. Effective quality assurance procedures require (meta)data to conform to community‐agreed standards. Nanosafety data offer a key reference point for developing best practices in data management for advanced materials, as their large‐scale generation coincided with the emergence of dedicated data quality criteria and concepts such as FAIR data. This work highlights frameworks, methodologies, and tools that address the challenges associated with the multidisciplinary nature of nanomaterial safety data. Existing approaches to evaluating the reliability, relevance, and completeness of data are considered in light of their potential for integration into harmonized standards and adaptation to advance material requirements. The goal here is to emphasize the importance of automated tools to reduce manual labor in making (meta)data FAIR, enabling trusted data re‐use and fostering safer, more sustainable innovation of advanced materials. Awareness and prioritization of these challenges are critical for building robust data infrastructures.
KW - Advanced materials
KW - Safety data
KW - Re-usability
KW - Nanosafety
KW - SSbD
KW - FAIR
KW - Standardisation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652918
DO - https://doi.org/10.1002/adsu.202500567
SN - 2366-7486
SP - 1
EP - 18
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65291
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schiaroli, Alice
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Eberwein, Robert
A1 - Ustolin, Federico
A1 - Cozzani, Valerio
T1 - Modelling the behaviour of cryogenic liquid hydrogen tanks engulfed in fire
N2 - The safe use of liquid hydrogen as a clean fuel requires a deep understanding of its behaviour in accident scenarios. Among other scenarios, the possible involvement of cryogenic liquid hydrogen tanks in engulfing fires is of particular concern, due to the potentially severe consequences. This study proposes a computational fluid dynamic model suitable to simulate the behaviour of liquid hydrogen tanks equipped with multi-layer insulation (MLI) engulfed in fire. An original approach has been developed to assess the progressive degradation of the performance of the thermal insulation, that is crucial in determining the tank pressurization and failure. The model is validated against full-scale experimental fire tests. The outcomes of the model reproduce the progressive pressurization and the opening time of the pressure relief valve within 2 % error. The results demonstrate the importance of accounting for the dynamic evolution of the progressive degradation of the insulation when evaluating tank pressurization, and they highlight the limitations of empirical, simplified state-of-the-art approaches. Furthermore, the analysis evidences the key role of the fire temperature in governing tank response, stressing the need for proper fire characterization to support reliable modelling of fire scenarios and the development of emergency planning and mitigation strategies ensuring the structural integrity of liquid hydrogen tanks during fire attacks.
KW - LH2
KW - LNG
KW - Fire
KW - Tank
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652920
DO - https://doi.org/10.1016/j.psep.2025.108319
SN - 0957-5820
VL - 206
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-65292
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dackermann, U.
A1 - Yu, Y.
A1 - Niederleithinger, Ernst
A1 - Li, J.
A1 - Wiggenhauser, Herbert
T1 - Condition Assessment of Foundation Piles and Utility Poles Based on Guided Wave Propagation Using a Network of Tactile Transducers and Support Vector Machines
N2 - This paper presents a novel non-destructive testing and health monitoring system using a network of tactile transducers and accelerometers for the condition assessment and damage classification of foundation piles and utility poles. While in traditional pile integrity testing an impact hammer with broadband frequency excitation is typically used, the proposed testing system utilizes an innovative excitation system based on a network of tactile transducers to induce controlled narrow-band frequency stress waves. Thereby, the simultaneous excitation of multiple stress wave types and modes is avoided (or at least reduced), and targeted wave forms can be generated. The new testing system enables the testing and monitoring of foundation piles and utility poles where the top is inaccessible, making the new testing system suitable, for example, for the condition assessment of pile structures with obstructed heads and of poles with live wires. For system validation, the new system was experimentally tested on nine timber and concrete poles that were inflicted with several types of damage. The tactile transducers were excited with continuous sine wave signals of 1 kHz frequency. Support vector machines were employed together with advanced signal processing algorithms to distinguish recorded stress wave signals from pole structures with different types of damage. The results show that using fast Fourier transform signals, combined with principal component analysis as the input feature vector for support vector machine (SVM) classifiers with different kernel functions, can achieve damage classification with accuracies of 92.5% ± 7.5%.
KW - Structural Health Monitoring
KW - Non-Destructive Testing
KW - Sensor network
KW - Support vector machine
KW - Utility poles
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434868
UR - http://www.mdpi.com/1424-8220/17/12/2938
DO - https://doi.org/10.3390/s17122938
SN - 1424-8220
VL - 17
IS - 12
SP - Article 2938, 1
EP - 16
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-43486
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stengel, Dominik
A1 - Thiele, K.
T1 - Measurements of downburst wind loading acting on an overhead transmission line in Northern Germany
N2 - Along an overhead transmission line in Northern Germany, a unique instrumentation of anemometers and force measurements is installed. Details of this test line with wind measurements along a horizontal axis are given. A recent event of a presumable downburst wind event is analyzed by means of available data and precedent works on thunderstorm analysis. The measured response of the conductors at the suspension tower is investigated and compared with time domain simulation of a finite element model.
T2 - X International Conference on Structural Dynamics, EURODYN 2017
CY - Rome, Italy
DA - 10.09.2017
KW - Non-synoptic wind event
KW - Downburst
KW - Overhead transmission line
KW - Finite element method
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-421239
DO - https://doi.org/10.1016/j.proeng.2017.09.578
SN - 1877-7058
VL - 199
IS - Supplement C
SP - 3152
EP - 3157
PB - Elsevier
AN - OPUS4-42123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Mitigation of railway induced vibration at the track, in the transmission path through the soil and at the building
N2 - This contribution presents some principles and some examples of the mitigation of railway-induced ground vibrations. The principles are different for the mitigation measures at the track, in the soil or at the building. Force transfer functions of isolated and un-isolated track-soil systems, reflected and transmitted wave amplitudes at walls and trenches in the soil, and the transfer of the (free-field) vibration amplitudes to the foundation amplitudes of the building are analysed. The mitigation effect can be calculated by exact or simplified formulas. Some examples with 3D (finite-element boundary-element), 2D (beam-on-support), and 1D track models, 2D and 1D soil models, detailed 3D building models and finite or infinite 1D wall-floor models are investigated to find out if simple models can be used for a satisfactory prediction of the mitigation effect. The 1D track examples show that the force transfer of the track without vehicle can be exactly calculated, whereas the total force transfer can be calculated approximately if appropriate wheelset masses per track length are used for the isolated and the un-isolated track. The mitigation effect of a filled trench is calculated by a 2D finite element model and the results compare with simple transmission formula if the stiffness per area rather than the wave impedances are used for the infill material. The base isolation of a building is analysed by a detailed 3D model and the results are similar to the analytic results of a single wall with floors on the soil. Other reduction measures as different floor and column dimensions are usually less effective so that the clearly best mitigation solution at a building is a partly or a complete base isolation.
T2 - X INTERNATIONAL CONFERENCE ON STRUCTURAL DYNAMICS (EURODYN 2017)
KW - Mitigation
KW - Soil-building interaction
KW - Base isolation
KW - Ground vibration
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420869
DO - https://doi.org/10.1016/j.proeng.2017.09.192
SN - 1877-7058
VL - 199
SP - 2312
EP - 2317
PB - Elsevier
CY - London
AN - OPUS4-42086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Röllig, Mathias
A1 - Steinfurth, Henrik
A1 - Augustin, Sven
A1 - Mecke, R.
A1 - Schiller, M.
A1 - Kernchen, A.
A1 - Kalisch, U.
A1 - Meinhardt, J.
A1 - Hennen, C.
A1 - Groll, E. T.
A1 - Arnold, T.
T1 - Characterisation of historic façades using active thermography with solar heating and optical methods
N2 - Active thermography is well suited for the detection of delaminations and cracks in façade elements like plaster and tiles. Not only artificial heating but also solar heating can be used if the adjustment of the façade and the weather conditions are suitable. Optical methods like laser scanners, photogrammetric methods and crack tracking sensors are providing geometrical 3D data which can be used for a 3D mapping of thermograms and for providing data with higher geometrical resolution. Thus, by the combination and fusion of these data, a comprehensive mapping and monitoring of damages of façade systems is possible.
T2 - 19th World Conference on Non-destructive Testing (WCNDT)
CY - München, Germany
DA - 13.06.2016
KW - Non-destructive testing
KW - Active thermography
KW - Solar heating
KW - Historic facades
KW - Optical methods
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366833
SN - 978-3-940283-78-8
VL - BB 158
SP - Mo.2.C.2., 1
EP - 8
PB - DGZfP
CY - Berlin
AN - OPUS4-36683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schlick-Hasper, Eva
A1 - Seidler, Oliver
A1 - Goedecke, Thomas
A1 - Kraume, M.
T1 - Helium leak testing of dangerous goods packagings
N2 - The International Dangerous Goods Regulations prescribe the immersion under water method (“bubble test”) as standard method for the leakproofness test of dangerous goods packagings. But this test procedure acts as a test method for leak localisation, not for quantitative leakage rates measurement. Additionally, the sensitivity in detecting leaks of small diameters is restricted, depending on the test liquid and the test pressure. The bubble test is not suitable for a comparison with quantitative limit leakage rates based on realistic transport conditions. This is especially important when estimating the risk of the formation of an explosive atmosphere during the intercontinental carriage of dangerous goods packagings in freight containers.
To compare measured leakage rates with limit leakage rates, a quantitative leak testing procedure is required. Therefore a new approach for dangerous goods packagings is implemented: The pressure technique by accumulation using Helium as a tracer gas.
This work presents the test equipment necessary for the quantitative measurement of Helium leakage rates through closures of different kinds of dangerous goods packagings. The essential steps to achieve good repeatable results are: A controlled Helium filling process to reach a defined test pressure in the test sample, a sufficient homogenisation of the Helium-air-mixture inside the test sample and the ensuring of a constant pressure level of the test sample during the test. The Helium loss rate of the accumulation chamber has to be measured separately to receive a correction factor for the measured leakage rates. Different constructional measures are introduced to prevent a disturbing influence of the Helium leakage rate of the filling valves on the measurement results. Methods to estimate the disturbing effect of Helium permeation through permeable parts of the test sample are also presented. As a supporting method for the experimental investigations the Helium sniffer test can be applied. This practical application-oriented advice can enable other users to establish a pressure technique by accumulation for their own technical field.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Gefahrgutverpackungen
KW - Dichtheit
KW - Helium
KW - Überdruckverfahren
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366358
SN - 978-3-940283-78-8
VL - 158
SP - p175, 1
EP - 10
AN - OPUS4-36635
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fuggini, C.
A1 - Zangani, D.
A1 - Wosniok, Aleksander
A1 - Krebber, Katerina
A1 - Franitza, P.
A1 - Gabino, L.
A1 - Weigand, F.
T1 - Innovative approach in the use of geotextiles for failures prevention in railway embankments
N2 - Maintenance and renewal costs of a typical railway, track and substructure represents 50–60% of the total costs of such infrastructure over its entire service life. Innovations in track and substructure are therefore fundamental to achieve a significant
impact on the overall cost reduction for the railways. Therefore new solutions for track improvements that are effective and that can minimize the interruption of traffic are needed. Moreover, failures of railway embankments happened recently in different regions of the world. Such events, such as the one happened in UK in February 2013 (http://www.bbc.co.uk/news/uk-england-south-yorkshire-21441070), are showing the importance of monitoring track and infrastructure coupled with the use of numerical models for the localization of the critical areas and the design of appropriate countermeasures. Indeed embankment failures, landslides and uneven settlements and similar events are becoming much more common than in the past due to climate changes, and this requires the infrastructure managers to look from a different perspective infrastructure maintenance issues. What was previously consider as “extreme” is now “common” and thus actions need to be taken to be ready when such events will happen. The aim is to mitigate their effects on the infrastructure and to minimize disruptions to train services and reduce maintenance costs to restore the normal service conditions. If this mental change happens, then the need for solutions and techniques for global asset monitoring and ground stabilization will probably increase. Among the others, geotextiles and geogrids for soil reinforcement used in combination with condition monitoring techniques have the potential for minimizing catastrophic events, whilst at the same time providing a good balance among costs and benefits (i.e. sustainability).
The paper describe a case study where the use of multifunctional geotextiles, able to provide both strengthening and monitoring functions, has been tested along a railroad near the city of Chemnitz (Germany). The results are here reported to show the potential use and the innovative aspect of this solution.
T2 - 6th Transport Research Arena (TRA)
CY - Warsaw, Poland
DA - 18.04.2016
KW - smart geotextile
KW - failure prevention
KW - railway embankment
KW - fiber optic sensor
KW - distributed sensor
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379256
DO - https://doi.org/10.1016/j.trpro.2016.05.154
VL - 14
SP - 1875
EP - 1883
PB - Elsevier B.V.
AN - OPUS4-37925
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
A1 - Said, Samir
A1 - Müller, Roger
T1 - Measurements on the vehicle-track interaction and the excitation of railway-induced ground vibration
N2 - Two railway measurement campaigns have been performed in Germany and Switzerland which yield insight in the vehicle-track-soil interaction. The campaign in Germany has included simultaneous measurement of vehicle, track, and soil vibrations during train runs with 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. Two ballast tracks, one on the soil surface and one on a concrete bridge, have been investigated as well as a slab track in a tunnel. Ten different sites in Switzerland have been measured for soil properties and train-induced ground vibrations, which allow to determine the excitation forces of the railway traffic. New axle-box measurements at some of the Swiss sites have been analysed to get further experimental evidence. All these measurements have been evaluated to characterize the excitation processes. Relations between vehicle vibration and ground vibration can be observed. The vehicle vibrations, namely the accelerations of the wheelsets, yield the dynamic forces due to the passage over the irregularities of the vehicle and the track. The ground vibrations are correlated to these dynamic forces to a certain extent. Some mid-frequency ground vibration amplitudes, however, are higher than expected from the dynamic excitation forces. The experimental observations can be explained by an irregular response to the passage of the static loads, that means the passage of the static loads over an irregular ballast or soil. This correct understanding of the excitation processes is important for the prediction as well as for the mitigation of railway induced ground vibrations.
T2 - X INTERNATIONAL CONFERENCE ON STRUCTURAL DYNAMICS (EURODYN 2017)
KW - Vehicle-track interaction
KW - Ground vibration
KW - Track vibration
KW - Railway measurement campaign
KW - Axle box measurements
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420889
DO - https://doi.org/10.1016/j.proeng.2017.09.390
SN - 1877-7058
VL - 199
SP - 2615
EP - 2620
PB - Elsevier
CY - London
AN - OPUS4-42088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Christina
A1 - Bertovic, Marija
A1 - Holstein, R.
A1 - Kanzler, Daniel
A1 - Pitkänen, J.
A1 - Ronneteg, U.
A1 - Heckel, Thomas
T1 - A plenary view on the vigour of our NDE reliability models
N2 - Using the Modular Reliability Model the three different main influencing elements, i.e. intrinsic capability (IC), application parameters (AP) and the human factors (HF), are, in the first instance, investigated separately. The intrinsic capability stands for the pure physical-technological process of the signal detection caused by the waves or the rays from a material defect in the presence of noise (driven by the material and the devices). This intrinsic capability is the upper bound of the possible reliability. Already when measuring this intrinsic capability for thick walled components the original one-parameter POD must be extended to a multiparameter POD, where, in addition to the defect size, a number of additional physical parameters, such as the grain size distribution (or attenuation), defect depth, and angle or surface roughness, must be considered. For real life cycle assessments it is necessary to evaluate the signal response from real defects. The industrial application factors, e.g. coupling conditions, limited accessibility, heat and environmental vibrations, diminish the reliability. The amount of reduction can be determined quantitatively, if the underlying conditions are controlled. In case they are not controlled it is necessary to count for a fluctuation in the reliability in the field anyway. The third group of important influencing factors are the human factors, which do not only cover the individual performance capability of the inspectors but also the design of the working place,the procedure, the teamwork quality, interaction with systems, the organization, and finally, the relationship between the companies involved in the inspection process and to which extend the responsible parties are aware of it. When comparing an “ideal inspection” with a “real inspection” it is worth while to look how the existing practices, rules and standards support reliable testing and where the “delta” is. In the context of vigor, with respect to the industrial end user, it needs to be shown how the level of reliability of NDE, influenced by the different factors, has an impact on acceptance or rejection of safety critical parts.
T2 - 5th European-American workshop on reliability of NDE
CY - Berlin, Germany
DA - 07.10.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312658
SN - 978-3-940283-53-5
IS - DGZfP-BB 144
SP - Lecture 2, 1
EP - 18
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, L. M.
A1 - Müller, J. T.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Schmidt, J.
A1 - Bekheet, M. F.
A1 - Gurlo, A.
A1 - Simon, U.
T1 - Hierarchically porous and mechanically stable monoliths from ordered mesoporous silica and their water filtration potential
N2 - Mechanically stable structures with interconnected hierarchical porosity combine the benefits of both small
and large pores, such as high surface area, pore volume, and good mass transport capabilities. Hence, lightweight micro-/meso-/macroporous monoliths are prepared from ordered mesoporous silica COK-12 by means of spark plasma sintering (SPS, S-sintering) and compared to conventionally (C-) sintered monoliths. A multi-scale model is developed to fit the small angle X-ray scattering data and obtain information on the hexagonal lattice parameters, pore sizes from the macro to the micro range, as well as the dimensions of the silica population. For both sintering techniques, the overall mesoporosity, hexagonal pore ordering, and amorphous character are preserved. The monoliths' porosity (77–49%), mesopore size (6.2–5.2 nm), pore volume (0.50–0.22 g cm-3
), and specific surface area (451–180 m2 g-1) decrease with increasing processing temperature and pressure. While the difference in porosity is enhanced, the
structural parameters between the C-and S-sintered monoliths are largely converging at 900 C, except for the mesopore size and lattice parameter, whose dimensions are more extensively preserved in the
S-sintered monoliths, however, coming along with larger deviations from the theoretical lattice. Their higher mechanical properties (biaxial strength up to 49 MPa, 724 MPa HV 9.807 N) at comparable porosities and ability to withstand ultrasonic treatment and dead-end filtration up to 7 bar allow S-sintered monoliths to reach a high permeance (2634 L m-2 h-1 bar-1), permeability (1.25 x 10^-14 m2), and ability to reduce the chemical oxygen demand by 90% during filtration of a surfactant-stabilized oil in water emulsion, while indicating reasonable resistance towards fouling.
KW - SAXS
KW - Hierarchically porous
KW - Silica
KW - Water filtration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555928
DO - https://doi.org/10.1039/D2NA00368F
SN - 2516-0230
SP - 1
EP - 17
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-55592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pohl, Rainer
A1 - Casperson, Ralf
A1 - Maierhofer, Christiane
A1 - Müller, Jan
A1 - Pelkner, Matthias
T1 - Gegenüberstellung von Wirbelstromprüfung und aktiver Thermografie an CFK-Versuchskörpern
N2 - In vielen Bereichen der Technik haben Konstruktionen unter Einsatz von CFK-Bauteilen und Komponenten die klassischen Metalle abgelöst. Die zerstörungsfreie Prüfung solcher CFK-Bauteile gewinnt somit zunehmend an Bedeutung. Ein mögliches Prüfverfahren ist dabei die Wirbelstromprüfung. Aufgrund der relativ geringen elektrischen Leitfähigkeit von CFK-Komponenten kommt hierbei häufig die sogenannte HF-Wirbelstromprüfung zum Einsatz.
In verschiedenen Untersuchungen der BAM konnten jedoch auch mit Wirbelstromprüfsystemen in niedrigen Frequenzbereichen gute Ergebnisse erzielt werden. Um die Möglichkeiten und Grenzen dieser konventionellen Wirbelstromprüfung auszuloten, wurden Messungen an Versuchskörpern durchgeführt, welche bereits bei der Validierung der Blitz- und Lock-in-Thermografie für neue Verfahrensnormen erfolgreich eingesetzt wurden. Ein Typ dieser Versuchskörper sind Flachproben aus CFK von 6 mm Dicke. In diesen wurden Flachbodenbohrungen mit Durchmessern zwischen 4 mm und 24 mm eingebracht. Die Restwandstärken liegen zwischen 0,06 mm und 3,66 mm. Ein weiterer CFK-Versuchskörper hat die Geometrie eines Stufenkeiles. Bei verschiedenen Stufenkeilen sind Wanddicken zwischen 1,4 mm und 5,4 mm realisiert worden. In diesen wurden künstliche quadratische Delaminationen mit Kantenlängen zwischen 2 mm und 20 mm eingebracht. Die Ergebnisse der Wirbelstromprüfung werden denen der aktiven Thermografie gegenübergestellt.
Zur Nachbildung von Kompositwerkstoffen wurden die flachen Versuchskörper mit geeigneten Versuchskörpern aus Aluminium und Stahl kombiniert. Die Wirbelstromprüfungen wurden mit einem handelsüblichen Prüfgerät im Frequenzbereich zwischen 500 Hz und 3 MHz und entsprechend angepassten Sensoren durchgeführt.
T2 - DGZfP Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Wirbelstromprüfung
KW - Aktive Thermografie
KW - CFK
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403607
SN - 978-3-940283-85-6
VL - 162
SP - 1
EP - 10
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-40360
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
A1 - Kanzler, D.
A1 - Pavlovic, Mato
A1 - Holstein, R.
T1 - Aktueller Stand der Diskussion zur Zuverlässigkeit der ZfP und den menschlichen Faktoren
N2 - Dass die Zuverlässigkeit der ZfP eine sehr wichtige Rolle bei der Bewertung sicherheitsrelevanter Systeme spielt, ist bekannt. Laut dem modularen Zuverlässigkeitsmodell für zerstörungsfreie Prüfprozesse hängt die Zuverlässigkeit von der innewohnenden (physikalisch-technischen) Fähigkeit der Prüfsystems, den Anwendungsparametern, den menschlichen Faktoren und dem organisatorischen Kontext ab. Seit Einführung des Modells während des ersten Workshops zur Zuverlässigkeit der ZfP (European-American Workshop on Reliability of NDE) wurde das Modell in weiteren fünf Workshops stetig weiterentwickelt, diskutiert und an den Stand der Wissenschaft angepasst. Das Ziel dieser Publikation ist es, den aktuellen Stand der Diskussion und die neusten Fragestellungen der internationalen Zuverlässigkeitsgemeinschaft vorzustellen. Im Einzelnen werden die Entwicklung fortgeschrittener Modelle zur Bewertung der Probability of Detection (POD), Bewertungsansätze im Bereich Structural Health Monitoring und Fragestellungen zu den menschlichen Faktoren dargestellt. Besonderer Wert wurde sowohl auf die Entwicklung, als auch auf die Anwendung der Ansätze in der industriellen Praxis gelegt.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Zuverlässigkeit
KW - Zerstörungsfreie Prüfung
KW - Probability of detection
KW - Human factors
KW - Reliability
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404861
SN - 978-3-940283-85-6
VL - DGZfP-Berichtsband BB 162
SP - 1
EP - 7
AN - OPUS4-40486
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mitzscherling, Steffen
A1 - Barth, Enrico
A1 - Götschel, S.
A1 - Homann, Tobias
A1 - Prager, Jens
A1 - Weiser, M.
T1 - Verbesserung und Qualifizierung der Ultraschallprüfung von Mischnähten im Primärkreis von KKW
N2 - Die im Primärkreislauf von Kernkraftwerken anzutreffenden austenitischen Schweiß- und Mischnähte sind nicht nur extrem sicherheitsrelevant, sondern stellen auch sehr hohe Anforderungen an die Materialprüfung. Neben der eingeschränkten Zugänglichkeit ist das makroskopische Gefüge der Schweißnaht für die Prüfung mit Ultraschall von höchster Bedeutung.
Um Materialfehler zuverlässig in Position und Größe bestimmen zu können, müssen die Kornorientierungen und die elastischen Konstanten des anisotropen Schweißnahtgefüges bekannt sein. Für die bildgebende Darstellung möglicher Materialfehler kommen folgende Arbeitsschritte zum Einsatz: Zunächst wird die Schweißnaht durchschallt, um mit einem inversen Verfahren wichtige Schweißnahtparameter wie beispielsweise die Kornorientierung bestimmen zu können. Auf der Basis dieser Parameter werden im nächsten Schritt die Schallwege mittels Raytracing (RT) simuliert. Zuletzt werden dieser RT-Simulation die Messdaten (A-Scans) von verschiedenen Sender- und Empfängerpositionen zugeordnet und nach der SAFT-Methode (Synthetic Aperature Focusing Technique) zeitaufgelöst überlagert. Die Kombination aus inversem Verfahren, RT und SAFT gewährleistet auch in anisotropen Werkstoffen eine ortsrichtige Visualisierung der Fehler.
Wir erläutern diese drei Verfahren und stellen die Prüfanordnung von Prüfkörpern mit künstlichen Testfehlern vor. Messdaten sowie deren Auswertung werden mit den Ergebnissen einer CIVA-Simulation verglichen.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Zerstörungsfreie Prüfung
KW - Ultraschall
KW - SAFT
KW - Schweißnaht
KW - Austenit
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404329
SN - 978-3-940283-85-6
VL - DGZfP BB 162
SP - P16, 1
EP - 8
AN - OPUS4-40432
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
T1 - Correction of diffuse X-ray detector based background
N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background Signals (backlight) of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering of the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beers law in single projections (radiographs).
When used as input data for computed tomography these violations are directly observed via modulation of the projected mass as a function of the rotation Phase and the samples aspect ratio (dynamics). The magnitude of the diffuse Background signal depends on the detector area covered by the projected sample. They are more pronounced the smaller the shaded area and the stronger the total attenuation.
Moreover, the local intensity mismatch depends on the attenuation of the sample.
We present very basic reference data measured with multiple metal foils at a synchrotron radiation source. Beam hardening artifacts can be excluded due to the monochromatic radiation. The proposed correction procedure assumes a constant (non-local) scattering mechanism.
T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Backlight
KW - X-ray detector
KW - Fluorescence screen
KW - Synchrotron radiography
KW - Computed tomography
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243589
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (Poster 24)
SP - 1
EP - 7
PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tatzel, Michael
A1 - von Blanckenburg, F.
A1 - Oelze, M.
A1 - Bouchez, J.
A1 - Hippler, D.
T1 - Late Neoproterozoic seawater oxygenation by siliceous sponges
N2 - The Cambrian explosion, the rapid appearance of most animal phyla in the geological record, occurred concurrently with bottom seawater oxygenation. Whether this oxygenation Event was triggered through enhanced nutrient supply and organic carbon burial forced by increased continental weathering, or by species engaging in ecosystem engineering, remains a fundamental yet unresolved question. Here we provide evidence for several simultaneous developments that took place over the Ediacaran–Cambrian transition: expansion of siliceous sponges, decrease of the dissolved organic carbon pool, enhanced organic carbon burial, increased phosphorus removal and seawater oxygenation. This evidence is based on Silicon and carbon stable isotopes, Ge/Si ratios, REE-geochemistry and redox-sensitive elements in a chert-shale succession from the Yangtze Platform, China. According to this reconstruction, sponges have initiated seawater oxygenation by redistributing organic carbon oxidation through filtering suspended organic matter from seawater. The resulting increase in dissolved oxygen levels potentially triggered the diversification of eumetazoans.
KW - Oxygenation
KW - Carbon cycle
KW - Silicon stable isotopes
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422339
DO - https://doi.org/10.1038/s41467-017-00586-5
SN - 2041-1723
VL - 8
SP - Article 621, 1
EP - 10
AN - OPUS4-42233
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zscherpel, Uwe
A1 - Schumacher, David
A1 - Redmer, Bernhard
A1 - Ewert, Uwe
A1 - Ullberg, C.
A1 - Weber, N.
A1 - Pantsar, T.
T1 - Digital radiology with photon counting detectors
N2 - The progress in X-ray detector electronics (sensitivity and speed) allows meanwhile fast single photon detection by a matrix detector. Combined photon counting and energy discrimination is implemented in the electronic circuit of each detector pixel. The company XCounter developed detectors based on CdTe single crystals, which can be tiled to larger areas and have a pixel size of 100ìm. The largest area available in beginning of 2014 is 50x75 mm². These detectors have very promising properties, which make them very suitable for NDT applications:
1. A CdTe attenuation layer of 750 µm thickness allows efficient X-ray detection up to ca. 300 keV. In counting mode only photon noise is important; no other detector noise sources need to be considered. There is no Offset signal without radiation.
2. Each of the detector pixels has two energy thresholds. These can be used for dual energy imaging for materials separation. Also the suppression of scattered radiation by energy thresholding will improve the image contrast sensitivity. First experiments will be presented which demonstrate the advantages of this new detector technology over the conventional charge integrating detectors.
A challenge is the development of a modified detector calibration procedure, which becomes critical at longer exposure times.
T2 - ECNDT 2014 - 11th European conference on non-destructive testing
CY - Prague, Czech Republic
DA - 06.10.2014
KW - Materials characterization
KW - Radiographic testing (RT)
KW - Digital detector array
KW - Photo counting
KW - Image quality
KW - Calibration
KW - Dual-energy
KW - Energy discrimination
KW - Digital radiology
KW - Detectors
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323063
UR - https://www.ndt.net/?id=16709
SN - 1435-4934
N1 - Geburtsname von Schumacher, David: Walter, D.
-
Birth name of Schumacher, David: Walter, D.
VL - 19
IS - 12
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-32306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Nellesen, J.
A1 - Hentschel, M.P.
A1 - Kupsch, Andreas
A1 - Tillmann, W.
T1 - Synchrotron-Refraktion mit in-situ Zugbelastung zur Charakterisierung der Schadensentwicklung in Metall-Matrix- Kompositen
N2 - Die Synchrotron-Refraktions-Topographie basiert auf der Brechung von Röntgenstrahlung an den Grenzflächen zwischen Materialien mit unterschiedlichem Brechungsindex. Refraktionseffekte verändern die Ausbreitungsrichtung der Röntgenstrahlung, welche mit Hilfe der Methode des Analyser-Based Imaging analysiert wird. Dabei wird ein Silizium-Einkristall im Strahlengang zwischen Probe und Detektor platziert. Dieser Analysator-Kristall filtert, innerhalb seiner Streuebene, die Röntgenstrahlung gemäß ihrer Ausbreitungsrichtung. Durch das Rastern verschiedener Winkelpositionen des Analysator-Kristalls erhält man das Winkelspektrum der von der Probe gebrochenen Strahlung. Aus dieser Rocking Curve lässt sich die spezifische innere Oberfläche der Probe bestimmen. Diese Information wird über einen 2D-Detektor mit einer nominellen Pixelgröße von 3,6 μm gewonnen. Die Installation einer Zugprüfmaschine ermöglicht es die Proben in verschiedenen Lastzuständen insitu zu untersuchen. Damit ist es möglich die spezifische innere Oberfläche in Abhängigkeit der Last darzustellen und so Schädigungsmechanismen abzuleiten. Der Vorteil bei der Ausnutzung des Refraktionseffekts gegenüber der einfachen Durchstrahlung ist die höhere Sensitivität gegenüber Defekten mit geringem Volumen aber großer Oberfläche. Somit werden auch Mikrorisse und, speziell bei Kompositen, die Enthaftung zwischen Matrix und Verstärkung (Partikel, Fasern) erfasst. In dieser Studie wurden Metall-Matrix-Komposite bestehend aus einer Aluminium-Matrix verstärkt mit Aluminiumoxid-Partikeln untersucht. Hierzu wurden knochenförmige Zugproben präpariert, deren Messlänge einen rechteckigen Querschnitt von 1,7 mm × 1,3 mm aufwies. Die Proben wurden einem Zugversuch unterzogen, welcher in Intervallen unterbrochen wurde. Bei jeder Unterbrechung wurde unter quasi-statischer Last die Rocking Curve gemessen und ein Radiogramm der spezifischen inneren Oberflächen berechnet. Dabei konnte ab dem Erreichen einer Last von ca. 600 N ein Anstieg der spezifischen inneren Oberfläche beobachtet werden. Demgegenüber zeigen die zum Vergleich durchgeführten Durchstrahlungsaufnahmen keinerlei Defekte. Daher belegt diese Untersuchung das Potential der Refraktion-Topographie zur frühzeitigen Erkennung von Schädigungen mit hoher Empfindlichkeit.
T2 - DGZfP Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Metall-Matrix-Komposite
KW - Schadensentwicklung
KW - Röntgen-Refraktions-Radiographie
KW - In-situ Zugbelastung
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-405794
SN - 978-3-940283-85-6
SP - 1
EP - 7
PB - DGZfP
AN - OPUS4-40579
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Kupsch, Andreas
T1 - Bewertung von CT-Rekonstruktionen mit DIRECTT
N2 - Modellrechnungen mit dem CT-Algorithmus DIRECTT (Direkte iterative Rekonstruktion computertomographischer Trajektorien) haben die Vorteile gegenüber anderen Ansätzen bezüglich Ortsauflösung und Dichte gezeigt, insbesondere auch für unvollständige Datensätze wie Limited View- und Region of Interest-Szenarien. Entsprechend dem Normalfall werden hier jedoch vollständige Datensätze von Modellen und Messungen und ihre Rekonstruktionen bewertet. Die Qualität von DIRECTT wird mit der Gefilterten Rückprojektion anhand der Modulations-Transfer-Funktion (MTF) sowie integraler Kenngrößen im Radon- und im Ortsraum verglichen. Zur Überprüfung der Rekonstruktionsgenauigkeit experimenteller Daten werden Mustermessungen einfacher Probengeometrien unter definierten physikalischen Bedingungen durchgeführt. Diese betreffen Monochromasie, Unterdrückung von Kantenartefakten und radiometrische Intensitätsbestimmung mit Einkanaldetektor.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Computertomographie
KW - DIRECTT
KW - Modulations-Transfer-Funktion
KW - CT-Algorithmus
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-286933
SN - 978-3-940283-49-8
IS - Poster 13
SP - 1
EP - 10
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28693
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Höhne, Christian
A1 - Boehm, Rainer
A1 - Prager, Jens
T1 - Detektion der Einhüllenden in SAFT-Daten durch Anwendung multidimensionaler analytischer Signale mit single-orthant-Spektren
N2 - Die Synthetic Aperture Focusing Technique (SAFT) ist ein Verfahren zur Verarbeitung von HF-Bildern, die an unterschiedlichen Prüfkopfpositionen aufgenommen wurden. Es wird in der zerstörungsfreien Werkstoffprüfung genutzt, um eine Abbildung von Materialfehlern innerhalb des Gebietes zu erstellen, auf das die Rekonstruktion angewandt wird. Die nach Abschluss der SAFT-Rekonstruktion zusammengestellten Informationen über Reflektoren liegen zunächst nach wie vor in Form von HF-Daten vor. Die Interpretierbarkeit der SAFT-Bilder ist im Allgemeinen davon abhängig, wie diese Daten vor der endgültigen Darstellung aufbereitet werden. Die Bildung der Amplitudeneinhüllenden aus dem zugehörigen analytischen Signal stellt eine Möglichkeit einer solchen Aufbereitung nach Anwendung des SAFT-Algorithmus dar. Sie ist jedoch nur im eindimensionalen Fall eindeutig definiert. In diesem Beitrag wird das Konzept der analytischen Signale mit single-orthant-Spektren aufgegriffen, um eine Detektion der Einhüllenden an mehrdimensionalen HF-Daten durchzuführen. Dabei wird über die Betragsquadrate aller möglichen nach dieser Definition zu bildenden analytischen Signale gemittelt. Es wird gezeigt, dass die Anwendung des beschriebenen Verfahrens einem Separationsansatz entspricht. Außerdem wird eine Möglichkeit aufgezeigt die Gültigkeit dieses Ansatzes anhand der totalen und partiellen Hilberttransformationen des Signals im konkreten Fall zu überprüfen. Die Ergebnisse dieser Methode zur Verbesserung von SAFT Bildern werden unter Verwendung synthetischer und experimenteller Daten an rekonstruierten Abbildungen verschiedener Reflektorarten beispielhaft dargestellt.
T2 - DACH-Jahrestagung 2012
CY - Graz, Austria
DA - 17.09.2012
KW - Ultrasonic testing (UT)
KW - Synthetic aperture focusing technique (SAFT)
KW - Analytic signal
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-327039
UR - https://www.ndt.net/search/docs.php3?id=14341
SN - 1435-4934
VL - 18
IS - 5
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-32703
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Kannengießer, Thomas
T1 - Rapid solidification during welding of duplex stainless steels – in situ measurement of the chemical concentration by Laser-Induced Breakdown Spectroscopy (LIBS)
N2 - Duplex stainless steels (DSS) are frequently used, especially in applications requiring high strength combined with high corrosion resistance in aggressive media. Examples include power plant components and maritime structures. During welding of these steels, local variations in chemical composition can occur. This results in ferritization of the material and negatively affects the mechanical properties of the components. In this work, tungsten inert gas (TIG) welding experiments were performed with DSS. Chemical composition analysis was realized in situ by using Laser Induced Breakdown Spectroscopy (LIBS). The aim of the work is to quantitatively measure the chemical composition in the weld seam of various DSS and to identify possible influences of welding parameters on the microstructure of the material. The chemical concentrations of the main alloying elements Cr, Ni, Mn on the surface of the sample during the welding process and the cooling process were measured. Mn and Ni are austenite stabilizers and their content increases during welding by using certain high alloyed filler material. Spectra were recorded every 1.3 s at a spacing of approximately 2 mm. During the cooling process the location of the measurement was not changed. The LIBS method is proofed to be suitable for the quantitative representation of the chemical compositions during the welding process.
T2 - ICASP-6
CY - Le Bischenberg, France
DA - 20.06.2022
KW - LIBS
KW - In situ measurement
KW - Duplex stainless steel
KW - TIG welding
KW - Evaporation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571308
DO - https://doi.org/10.1088/1757-899X/1274/1/012018
VL - 1274
SP - 1
EP - 8
PB - IOP Publishing
CY - Bristol
AN - OPUS4-57130
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pfennig, Anja
A1 - Kranzmann, Axel
T1 - Impact of saline aquifer water on surface and shallow pit corrosion of martensitic stainless steels during exposure to CO2 environment (CCS)
N2 - Pipe steels suitable for carbon capture and storage technology (CCS) require resistance against the corrosive environment of a potential CCS-site, e.g. heat, pressure, salinity of the aquifer, CO2-partial pressure. Samples of different mild and high alloyed stainless injection-pipe steels partially heat treated: 42CrMo4, X20Cr13, X46Cr13, X35CrMo4 as well as X5CrNiCuNb16-4 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h - 8000 h in a CO2-saturated synthetic aquifer environment similar to possible geological on-shore CCS-sites in the northern German Basin. Main corrosion products are FeCO3 and FeOOH. Corrosion rates obtained at 100 bar are generally much lower than those measured at ambient pressure. Highest surface corrosion rates are 0.8 mm/year for 42CrMo4 and lowest 0.01 mm/year for X5CrNiCuNb16-4 in the vapour phase at ambient pressure. At 100 bar the highest corrosion rates are 0.01 mm/year for 42CrMo4, X20Cr13 (liquid phase), X46Cr13 and less than 0.01 mm/year for X35CrMo4 and X5CrNiCuNb16-4 after 8000 h of exposure with no regard to atmosphere. Martensitic microstructure offers good corrosion resistance.
T2 - 8th International Conference on Future Environment and Energy (ICFEE 2018)
CY - Phuket, Thailand
DA - 10.01.2018
KW - CCS
KW - CO2 corrosion
KW - Pipeline
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465896
DO - https://doi.org/10.1088/1755-1315/150/1/012012
VL - 150
SP - 81
EP - 90
PB - IOP Publ.
AN - OPUS4-46589
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schumm, A.
A1 - Martin, E.
A1 - Beaumont, M.
A1 - Ewert, Uwe
A1 - Kolkoori, Sanjeevareddy
A1 - Zscherpel, Uwe
A1 - Wrobel, Norma
A1 - Redmer, Bernhard
T1 - A comparative study on the performance of digital detector systems for high energy applications
N2 - For cast components reaching or exceeding total material thicknesses of 150mm, high energy sources such as linear accelerators or Betatrons are required in order to obtain reasonable exposure times. In this study, the performance of digital detector systems, involving imaging plates (IP) and digital detector arrays (DDA), was evaluated with respect to the testing class B requirements as formulated in the standard EN ISO 17636-2. As a reference, traditional radiographic film and a Cobalt-60 source was used. With film exposures, testing class B was achieved with Co-60 and Betatron (7.5 MV) at longer exposure times. The preliminary results show that the testing class B was not obtained with the examined digital detector arrays (DDA) and the high resolution imaging plates (IP) , even at 40, 60 and 80 minutes exposure time with a 7.5 MV Betatron. Class A was achieved using high resolution imaging plates with optimized metal filters between object and IPs and a high resolution DDA with intermediate Cu filters. Class A was also achieved applying a DDA with lower basic spatial resolution than required by Table B.13 of EN ISO 17636-2, but using the compensation principle as described in this standard. The next generation of digital detector arrays might potentially be able to obtain class B performance with the expected spatial resolution and sensitivity improvements.
T2 - ECNDT 2014 - 11th European conference on non-destructive testing
CY - Prague, Czech Republic
DA - 06.10.2014
KW - Radiography
KW - Image quality
KW - Betatron
KW - Digital detector array (DDA)
KW - Casting
KW - Standards
KW - High energy radiography
KW - Comparison of detectors
KW - Steel weldment
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323075
UR - https://www.ndt.net/?id=16394
SN - 1435-4934
VL - 19
IS - 12
SP - 1
EP - 6
PB - NDT.net
CY - Kirchwald
AN - OPUS4-32307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pfeiffer, F.
A1 - Bagyan, I.
A1 - Alfaro Espinoza, Gabriela
A1 - Zamora-Lagos, M.-A.
A1 - Habermann, B.
A1 - Marin-Sanguino, A.
A1 - Oesterhelt, D.
A1 - Kunte, Hans-Jörg
T1 - Revision and reannotation of the Halomonas elongata DSM 2581(T) genome
N2 - The genome of the Halomonas elongata type strain DSM 2581, an industrial producer, was reevaluated using the Illumina HiSeq2500 technology. To resolve duplication-associated ambiguities, PCR products were generated and sequenced. Outside of duplications, 72 sequence corrections were required, of which 24 were point mutations and 48 were indels of one or few bases. Most of these were associated with polynucleotide stretches (poly-T stretch overestimated in 19 cases, poly-C underestimated in 15 cases). These problems may be attributed to using 454 technology for original Genome sequencing. On average, the original genome sequence had only one error in 56 kb. There were 23 frameshift error corrections in the 29 protein-coding genes affected by sequence revision. The genome has been subjected to major reannotation in order to substantially increase the annotation quality.
KW - Frameshift
KW - Genome annotation
KW - Genome sequencing
KW - Halomonas elongata
KW - Halophilic bacteria
KW - Sequence revision
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403292
DO - https://doi.org/10.1002/mbo3.465
SN - 2045-8827
VL - 6
IS - 4
SP - Article e465, 1
EP - 6
PB - Wiley
AN - OPUS4-40329
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - D'Accardi, E.
A1 - Ulbricht, Alexander
A1 - Krankenhagen, Rainer
A1 - Palumbo, D.
A1 - Galietti, U.
T1 - Capability of active thermography to detect and localize pores in Metal Additive Manufacturing materials
N2 - Active thermography is a fast, contactless and non-destructive technique that can be used to detect internal defects in different types of material. Volumetric irregularities such as the presence of pores in materials produced by the Additive Manufacturing processes can strongly affect the thermophysical and the mechanical properties of the final component.
In this work, an experimental investigation aimed at detecting different pores in a sample made of stainless AISI 316L produced by Laser Powder Bed Fusion (L-PBF) was carried out using pulsed thermography in reflection mode. The capability of the technique and the adopted setups in terms of geometrical and thermal resolution, acquisition frequency and energy Density of the heating source were assessed to discern two contiguous pores as well as to detect a single pore. Moreover, a quantitative indication about the minimum resolvable pore size among the available and analysed defects was provided. A powerful tool to assess the Limits and the opportunities of the pulsed technique in terms of detectability and localizability was provided by comparing active thermography results to Computed Tomography as well as a related Finite Element Analysis (FEA) to simulate the pulsed heating transfer with Comsol.
T2 - 49th Italian Association for Stress Analysis Conferencee (AIAS 2020)
CY - Online meeting
DA - 02.09.2020
KW - Additive manufacturing
KW - Laser powderbed fusion
KW - Pores
KW - Thermography
KW - Micro-CT
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519231
DO - https://doi.org/10.1088/1757-899X/1038/1/012018
VL - 1038
SP - 1
EP - 17
PB - Institute of Physics
CY - London
AN - OPUS4-51923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rothbart, Nick
A1 - Maierhofer, Christiane
A1 - Röllig, Mathias
A1 - Sengebusch, M.
A1 - Goldammer, M.
A1 - Hohlstein, F.
A1 - Koch, J.
A1 - Kryukov, I.
A1 - Mahler, G.
A1 - Stotter, B.
A1 - Walle, G.
T1 - Ringversuche zur Blitzthermografie
N2 - Im Rahmen des INS-Projekts „Durchführung von Ringversuchen zur Normung und Standardisierung der aktiven Thermografie mit Blitzlichtanregung“ wurden Ringversuche durchgeführt, die die Zuverlässigkeit, Vergleichbarkeit und Effektivität der Blitzthermografie für unterschiedliche Prüfprobleme nachweisen sollten. Weiterhin sollten diese Untersuchungen als Methodenvalidierungsstudie die Richtigkeit und Präzision der Blitzthermografie nachweisen und Vergleichsinformationen unterschiedlicher Geräteausstattungen liefern. Im Normausschuss NA 062-08-27 AA „Visuelle und thermografische Prüfung“ des DIN werden die Ergebnisse die Erarbeitung eines Normentwurfs zur Blitzthermografie unterstützen. In diesem Beitrag werden die Ringversuche beschrieben und ausgewählte Ergebnisse präsentiert.
T2 - Thermographie-Kolloquium 2015
CY - Leinfelden-Echterdingen, Germany
DA - 01.10.2015
KW - Thermografie mit Blitzanregung
KW - Ringversuch
KW - Testkörper
KW - Standardisierung
KW - Signal-zu-Rausch-Verhältnis
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345460
SN - 978-3-940283-74-0
IS - DGZfP BB 154
SP - Vortrag 12, 1
EP - 8
AN - OPUS4-34546
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hosseini, Seyed M. H.
A1 - Heckel, Thomas
A1 - Boehm, Rainer
A1 - Brackrock, Daniel
A1 - Gohlke, Dirk
A1 - Riemer, Stefanie
A1 - Gaal, Mate
T1 - Gegenüberstellung der Performance verschiedener Ultraschallsensorsysteme bei der Untersuchung von CFK-Platten
T1 - Comparison of performance of different ultrasonic systems for inspection of CFRP plates
N2 - Die Zahl der industriellen Anwendungen mit Einsatz von Faserverbundwerkstoffen wächst kontinuierlich vor allem wegen der exzellenten Materialeigenschaften und des geringen Gewichtes dieses Werkstoffes. Entsprechend steigen die Anforderungen an zerstörungsfreie Prüfsysteme zur Gewährleistung des sicheren Betriebes von Komponenten und Strukturen bestehend aus Verbundwerkstoffen.
Im Rahmen des EU-Projekes VITCEA (Validated Inspection Techniques for Composites in Energy Applications) wird das Ziel verfolgt, neue Prüfverfahren für moderne Verbundwerkstoffe zu entwickeln und zu validieren. Im Vordergrund steht hierbei als Applikation im Industriesektor Energieversorgung die Prüfung von sicherheitsrelevanten Komponenten von onshore und offshore Windkraftanlagen, wie z.B. deren Rotorblätter und tragende Strukturen.
Eine Teilaufgabe innerhalb des Projektes stellen der Vergleich und die Validierung verschiedener Ultraschallprüfmethoden bezüglich ihrer Fähigkeit zum Nachweis der typischen Herstellungs- und betriebsbedingten Materialschädigungen von CFK und GFK dar.
Neben verschiedenen konventionellen Ultraschall-Prüftechniken, werden die Phased-Array-Prüfung, insbesondere die Prüfung mit Matrixarrays, sowie die Untersuchung mit berührüngsloser Luftultraschalltechnik bezüglich ihrer Nachweisgrenzen und der Möglichkeiten zur Fehlercharakterisierung an Faserverbundwerkstoffen untersucht. Die Ergebnisse werden mit Untersuchungen mit thermographischen Methoden und Mikrowellentechnik verglichen.
N2 - Applications of fiber-reinforced plastic (FRP) composites in modern industries are increasing due to their considerable advantages such as light weight and excellent mechanical properties. Accordingly, importance of operational safety of modern structures made of advanced composites by ensuring the material quality has led to increasing demands for development of non-destructive evaluation (NDE) systems. In the context of a European-project entitled 'Validated Inspection Techniques for Composites in Energy Applications' (VITCEA), the aim is to develop and validate traceable procedures for novel NDE techniques with contrasting damage detection capabilities in energy related applications such as wind and marine turbine blades, nacelles, oil and gas flexible risers. As a part of VITCEA, the present study focuses on application of ultrasonic tests (UTs) including conventional, matrix array, immersion and air-coupled, for quantitative defect detection and quality characterization of FRP structures. Results of UTs are subjected to be compared with other NDE approaches which are applicable for inspection of FRPs such as thermography and microwave techniques.
Within the present report, the initial results obtained from conventional and immersion UTs are presented and their capabilities as well as limitations are discussed. In order to validate theoretical predictions and simulation results, further experimental tests will be performed in the framework of the project using reference defect artefacts in which the defect sizes and locations are well defined and controlled.
T2 - DGZfP Seminar des Fachausschusses Ultraschallprüfung
CY - Saarbrücken, Germany
DA - 03.11.2015
KW - Ultraschallsensorsysteme
KW - Faserverbundwerkstoffe
KW - Kontakttechnik Technik
KW - Tauchtechnik
KW - Phased-Array-Prüfung
KW - Luftultraschall
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-349264
UR - https://www.dgzfp.de/Portals/ultraschall2015/BB/3.pdf
SP - Vortrag 3, 1
EP - 10
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-34926
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Maierhofer, Christiane
T1 - Einzelblitz vs. Multiblitz - Blitzthermografie mit mehreren Blitzen
N2 - Die Blitzthermografie weist eine Reihe von Vorteilen gegenüber anderen Verfahren der aktiven Thermografie auf und hat daher eine relativ große Verbreitung in Forschung und Industrie gefunden. Ein wesentlicher Nachteil ist jedoch die begrenzte Energie, die pro Blitz genutzt werden kann. Es stellt sich die Frage, ob sich durch mehrere kurz hintereinander ausgeführte Blitze eine Verbesserung des Energieeintrags erreichen lässt. Zur experimentellen Untersuchung dieser Frage wurde ein Versuchsstand mit vier Blitzlampen so umgerüstet, dass die Blitzlampen zeitgleich oder nacheinander mit einer regelbaren Verzögerung ausgelöst werden können („Multiblitz“). Als Probekörper dienten Platten aus CFK, an deren Rückseite Flachbodenbohrungen (FBB) eingebracht worden waren. Betrachtet wurde jedoch nur der absolute Temperaturhub am ungestörten Material. Die Experimente zeigen relativ geringe Effekte im Prozentbereich, wie sie auch gemäß einer quantitativen Abschätzung zu erwarten sind. Interessanterweise vergrößerte sich der Einfluss der Multiblitzanregung auf die Energieeinkopplung deutlich bei einem etwas vergrößerten Abstand zwischen Blitzlampen und untersuchter Oberfläche. Die Ursache für diesen Effekt ist derzeit unklar, vermutet werden eine Temperaturabhängigkeit und/oder eine Abstandsabhängigkeit des Wärmübergangskoeffizienten im Konvektionsterm.
T2 - Thermographie-Kolloquium 2015
CY - Leinfelden-Echterdingen, Germany
DA - 01.10.2015
KW - Thermografie
KW - Blitzthermografie
KW - Konvektion
KW - Wärmeverluste
KW - Einkoppeleffizienz
KW - Energiekopplung
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345487
SN - 978-3-940283-74-0
VL - 154
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-34548
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Dohse, Elmar
A1 - Bartusch, Jürgen
A1 - Kreutzbruck, Marc
T1 - Luftultraschallprüfung von CFK mit planaren und fokussierenden Wandlern
N2 - Für die Prüfung von Leichtbaustrukturen ist in den letzten Jahren ein vermehrter Einsatz der Luftultraschallprüfung zu verzeichnen. Insbesondere eignet sich Luftultraschall für die Prüfung von Faserkunststoffverbunden und hybrider Werkstoffverbunde, die ihre Anwendung in der Automobilindustrie und Luftfahrt finden. Für den Bau von marktüblichen Luftultraschall-Wandlern werden Piezokomposite mit Anpassschichten versehen. Ihre Herstellung ist allerdings sehr anspruchsvoll und die erreichbaren Signal-Rausch-Abstände sind für viele Prüfprobleme als noch nicht ausreichend einzustufen. Zwecks gesteigerter Effizienz beim Schallübertrag in die Luft wurden Luftultraschall-Sender und -Empfänger aus zellulärem Polypropylen entwickelt. Dieses piezoelektrische Material ist aufgrund seiner geringer Dichte und seiner sehr geringen Schallgeschwindigkeit an die niedrige akustische Impedanz der Luft deutlich besser angepasst, als die üblicherweise verwendeten Anpassschichten. Letztere können bei Polypropylen-Wandlern daher gänzlich vermieden werden.
In diesem Beitrag wird Luftultraschall-Prüfung an zwei verschiedenen CFK-Testkörpern vorgestellt: an einer Platte mit T-Stringern aus dem Seitenleitwerk eines Flugzeugs und an einer Platte mit künstlich eingebrachten Fehlern. Es wurde mit unterschiedlichen planaren und fokussierenden Wandlern geprüft. Marktübliche Wandler mit Anpassschichten wurden mit den selbstentwickelten Wandlern aus zellulärem Polypropylen verglichen. Der Signal-Rausch-Abstand und die laterale Auflösung wurden sowohl im Prüfaufbau mit senkrechter Einschallung als auch mit Schrägeinschallung gemessen. Die Ergebnisse zeigen, dass die Schrägeinschallung zwar den Signal-Rauschabstand erhöht, aber die laterale Auflösung verschlechtern kann.
T2 - DACH Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-349751
UR - http://jt2015.dgzfp.de/Portals/jt2015/BB/mi1a3.pdf
SP - Mi.1.A.3-1
EP - Mi.1.A.3-9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-34975
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Meinig, Silvia
A1 - Heckel, Thomas
T1 - Bestimmung der Richtcharakteristik von Senkrecht- und Winkelprüfköpfen in Kontakttechnik
N2 - Für den stetigen Einsatz und die erhöhten Anforderungen bei der mechanisierten Prüfung sowie in der Handprüfung ist notwendig, einen möglichst genauen Eindruck bzgl. Funktionsweise und Zuverlässigkeit der eingesetzten Prüfmittel zu besitzen. Prüfköpfe weisen, wie jedes andere technische Erzeugnis gewisse Toleranzen hinsichtlich Fertigungs- und Alterungsprozessen auf, welche sich speziell bei Winkelprüfköpfen durch eine Verschiebung des Nominalwinkels äußern können. Die Definition der Parameter von Prüfköpfen und entsprechende Methoden zu deren Überprüfung sind in der DIN EN 12668-2 geregelt.
Von der BAM werden für diese Aufgaben Richtcharakteristikmessplätze eingesetzt. Um auf die gestiegenen Anforderungen hochauflösender Prüfungen zu reagieren wurde der Richtcharakteristikmessplatz modernisiert. Dabei wurde für die teil-automatisierte Untersuchung der akustischen Parameter (z.B. Einschallwinkel) unter Verwendung digitaler Messdatenverarbeitung - ein neuer Messplatz für die Überprüfung sowie Untersuchung von Prüfkopftoleranzen und Alterungsprozessen realisiert. Der Messplatz verfügt über eine hochauflösende Messdatenerfassung sowie einer automatisierten Protokollierung der erhobenen Messdaten.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-336729
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Poster 57, 1
EP - 4
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-33672
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlke, Dirk
A1 - Heckel, Thomas
T1 - Bestimmung der Richtcharakteristik von fokussierenden Prüfköpfen in Tauchtechnik
N2 - Für eine hochauflösende Untersuchung von sicherheitsrelevanten Bauteilen innerhalb der Tauchtechnik haben fokussierende Prüfköpfe eine hohe Verbreitung erlangt. Für den Einsatz moderner und komplexer Rekonstruktionsverfahren bildet jedoch die Kenntnis über Schallfeldgeometrie, insbesondere die Lage und Ausdehnung der Fokusbereichs und die Empfindlichkeit des verwendeten Prüfkopfs in Abhängigkeit zum Schallweg, eine entscheidende Rolle für die Datenrekonstruktion und die abschließende Bauteildiagnose.
Für die automatisierte Bestimmung der wichtigsten Kenngrößen (bspw. Lage und Länge des Fokuspunkts bzw. Fokusschlauchs, sowie des Schallbündel-durchmessers) wurde die Schalldruckverteilung mechanisiert, vierdimensional (x,y,z,t) vermessen und unter Einsatz der digitalen Signal- und Bildverarbeitung, ein vollautomatisches Analysewerkzeug erarbeitet. Weiterhin konnte anhand des Messdatensatzes und unter Einsatz von dreidimensionalen Rekonstruktions- und Visualisierungstechniken das Schallfeld bzw. die Schalldruckverteilung dreidimensional abgebildet werden und für etwaige Nachuntersuchungen von Simulationsergebnissen oder allein zur Visualisierung eingesetzt werden.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-336733
SN - 978-3-940283-68-9
IS - 152
SP - P46, 1
EP - 4
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-33673
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Myrach, Philipp
A1 - Schlichting, Joachim
A1 - Maierhofer, Christiane
A1 - Kreutzbruck, Marc
T1 - Laser-Thermografie für die schnelle Prüfung auf mikroskopische Risse in reflektierenden metallischen Oberflächen
N2 - Thermografische ZfP-Verfahren erlauben die Erkennung einer Vielzahl von Defekten in unterschiedlichsten Werkstoffen. Neue Ansätze unter Verwendung von Lasern ermöglichen darüber hinaus die Prüfung auf Oberflächenrisse. Wir stellen die neuesten Entwicklungen dieser vielversprechenden Technik vor und zeigen warum deren Einsatz potentiell die Standardprüfverfahren Magnetpulver- bzw. Eindringprüfung für eine Reihe von Prüfproblemen beerben könnte. Hierzu stellen wir die Prüfergebnisse zu unterschiedlichen metallischen Werkstoffen, Rissgrößen und -typen in Abhängigkeit der Prüfparameter vor. Die aktuelle Grenze der Nachweisempfindlichkeit für die mittels klassischer Thermografie schwer prüfbaren hochreflektierenden Metalloberflächen liegt mit Rissbreiten und -tiefen von weni-gen Mikrometern im Bereich der fluoreszierenden Magnetpulver- und Eindringprüfung. Dabei sind weder Verbrauchsmittel noch eine Oberflächenpräparation notwendig und eine Prüfung kann berührungslos und automatisiert über Entfernungen im Meter-Bereich erfolgen.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Thermografie
KW - Laser
KW - Risse
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-288706
SN - 978-3-940283-49-8
IS - DGZfP-BB 141 (Di.2.A.4)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28870
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kolkoori, Sanjeevareddy
A1 - Wrobel, Norma
A1 - Osterloh, Kurt
A1 - Redmer, Bernhard
A1 - Deresch, Andreas
A1 - Ewert, Uwe
T1 - Hochenergieradiographie - Erkennung von Einzelheiten in großen, komplexen Schichttiefen
N2 - Zur Durchstrahlung großer, dichter Objekte reichen die Energien, die mit normalen Röntgenröhren erzielt werden können, ab gewissen Schichtdicken nicht mehr aus. Als hochenergetische Strahlenquellen stehen Kobalt-60 und Elektronenbeschleuniger zur Verfügung. Als Einschränkung der Hochenergieradiographie ist der geringere Kontrast besonders beim Vorhandensein leichterer Objekte umgeben von Körpern bestehend aus schweren Elementen anzusehen. Es ist daher zu erwarten, dass Objekte aus organischen Substanzen hinter dicken Schwermetallwänden oder in Bohrungen von Metallblöcken schwer zu erkennen sind. Im Gegensatz zu einem Gammastrahler wie Kobalt-60 mit den beiden Spektrallinien um 1,3 MeV besitzt die Bremsstrahlung aus einem Beschleuniger einen wesentlichen Anteil an niederenergetischer Strahlung, der fließend zu höheren Energien übergeht. Es wird hier untersucht, welche Signaturen von leichten Materialien in einer Umgebung aus Schwermetall bis zu welcher Dicke und bis zu welchem Komplexizitätsgrad erkennbar sind. Mit einem Betatron (JME X-ray Betatron 7,5 MeV) und einem Matrixdetektor (Perkin Elmer XRD 1621) wurden Aufnahmen von unterschiedlichen leichten Objekten angefertigt, die zunehmend in eine Umgebung aus Schwermetallen gestellt wurden. Mit unterschiedlichen Energieeinstellungen wurde untersucht, inwieweit eine Materialerkennung hinter welcher Abschirmung möglich ist. Die experimentellen Ergebnisse werden mit Simulationen verglichen, die mit einer Software zur Modellierung von Durchstrahlungsverfahren (aRTist) erzeugt wurden. Dabei wird dem Problem der Aufhärtung bei Anwendung von Bremsstrahlung Rechnung getragen. Die Ergebnisse können sowohl zur Erkennung von Fremdkörpern in Maschinen oder Pumpen als auch zur Überprüfung von Frachtladungen im Bereich der öffentlichen Sicherheit und bei Zollkontrollen dienen.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Hochenergieradiographie
KW - Containerprüfung
KW - Materialerkennung
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-288589
SN - 978-3-940283-49-8
IS - DGZfP-BB 141 (Mo.2.A.4)
SP - 1
EP - 9
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28858
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Doroshtnasir, Manoucher
A1 - Maierhofer, Christiane
A1 - Brackrock, Daniel
A1 - Brekow, Gerhard
T1 - Charakterisierung einer durch Überlast geschädigten GFK-Platte mit Thermografie und Ultraschall
N2 - Eine GFK-Platte mit eingefräster Nut wurde in einem Zugversuch mit
ca. 90 kN belastet, was zu einer sichtbaren Veränderung an den Seitenflächen führte.
Anschließend wurde die Platte mit Ultraschall und Thermografie auf innere Schädigungen untersucht. Beide Verfahren konnten räumlich ausgedehnte Bereiche mit zahlreichen Anzeigen nachweisen, jedoch keine geschlossene Fläche. Mit UT wurden außerdem porenreiche oberflächennahe Schichten in dem Material detektiert. Diese Poren verringerten die Nachweisempfindlichkeit beider Messverfahren.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Blitzthermografie
KW - Matrixarray
KW - GFK
KW - Delamination
KW - Überlast
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-285563
SN - 978-3-940283-49-8
IS - Mi.3.A.1
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28556
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
T1 - NDT for microstructure and moisture investigation of porous building material
N2 - Non-destructive testing methods are mostly applied and established for the detection of embedded mounting parts or structural defects in building elements. The assessment of the concrete microstructure or microstructural changes like chemical alterations or the formation of microcracks, e.g. due to material aging, freeze-thaw cycles, alkali-silica reaction and ettringite, is not in the focus of ndt research though. Concrete moisture and enhanced salt contents, which usually trigger all chemical microstructural changes, are other material properties, lacking reliable ways of measuring. But, the assessment of such material properties, on the long term also in a depth resolved manner, is definitely important, when the sustainability of our concrete infrastructure buildings shall be evaluated.
New consideration like the potential use of ndt, in particular the combination of different methods and alternate ways of data analysis are subject of research currently undertaken at BAM. These approaches involve for example working towards (i) a deeper understanding of how to measure moisture distributions reliably and follow transport phenomena, (ii) the use of stray phenomena in radar and ultrasound to locate material inhomogeneities or (iii) the application of LIBS for the delineation of diffusion and migration processes but also (iv) the use of new tools for data analysis like data fusion. First results are presented and new ideas discussed.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Screed
KW - Moisture
KW - Non-destructive testing
KW - Radar
KW - Microstructure
KW - Monitoring
KW - Concrete deterioration
KW - Cracking
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347593
UR - http://www.ndt.net/?id=18354
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 5
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Osterloh, Kurt
A1 - Fratzscher, Daniel
A1 - Jechow, Mirko
A1 - Bücherl, T.
A1 - Schillinger, B.
A1 - Hasenstab, A.
A1 - Zscherpel, Uwe
A1 - Ewert, Uwe
T1 - Limited view tomography of wood with fast and thermal neutrons
N2 - Neutrons are absorbed particularly by hydrogen containing materials so
they can be used as a tool for visualising heterogeneous density distributions of organic materials. Penetration limits are set by the layer thicknesses and the neutron energies applied. In case of specimens with a flat shape the situation may be encountered that the object only could be penetrated in selected directions. In addition, the overall size may exceed the beam diameter and thus the viewing window if a certain region of interest should be studied by tomography without destroying the integrity of the specimen.
This study shows the capabilities and limits of thermal and fast neutrons to investigate flat wooden specimens such as boards and girders by neutron tomography under such circumstances. Taking projections was impaired either by the limits of penetrability or by the total size of the object. As a consequence, projections were included for reconstruction only from a limited angular range of 90°. It could be shown that an approach based on the slice theorem was capable to visualise structural features along the beam directions while simply omitting the perpendicular ones without causing additional artefacts.
Small samples with a thickness of up to 2 cm but several times broader could be studied with the ANTARES facility of the FRM II neutron source in Garching providing thermal neutrons while larger objects required a beam of higher energy as available in the NECTAR facility of the same institution. The fast (fission) neutrons (1.5 – 2 MeV) of this site allowed investigating an area of interest inside a girder with a cross section of 23.5 x 49 cm². Internal features such as inclusions could be detected as well as a heterogeneous density distribution in glue layers.
T2 - International symposium on digital industrial radiology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Computed tomography
KW - Slice theoreme
KW - Limited angle tomography
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250663
SN - 978-3-940283-34-4
VL - 128
SP - 1
EP - 5
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-25066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pohl, Rainer
A1 - Casperson, Ralf
A1 - Eckey, Andreas
A1 - Sickert, Roland
T1 - Passiver induktiver Sensor zur Zustandsüberwachung rotierender metallischer Bauteile
N2 - Häufig müssen rotierende metallische Bauteile im Betrieb auf das Entstehen rissartiger Fehler überwacht werden. Hierbei besteht im Allgemeinen die Anforderung, trotz extrem schwieriger Umweltbedingungen eine sichere Prüfaussage zu gewährleisten. Es wurden Untersuchungen durchgeführt, inwieweit passive induktive Sensoren in der Lage sind, diese Anforderungen zu erfüllen. Hierzu wurden verschiedene einfache Sensormodelle aufgebaut und an verschiedenen Vergleichsfehlern erprobt. Die Ergebnisse der Untersuchungen werden vorgestellt. Insbesondere die Möglichkeiten und Grenzen dieser einfachen Sensortypen werden herausgearbeitet.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Induktiver Sensor
KW - Rotierendes Bauteil
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-285552
SN - 978-3-940283-49-8
IS - P30
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28555
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Igartua, A.
A1 - Fdez-Pérez, X.
A1 - Illarramendi, I.
A1 - Luther, R.
A1 - Rausch, J.
A1 - Woydt, Mathias
ED - Carmo, J. P.
ED - Ribeiro, J. E.
T1 - Biolubricants and triboreactive materials for automotive applications
N2 - The text deals with passenger car motor oils (PCMO) with reduced metal-organic additives.
KW - Biolubricants
KW - Passenger car motor oils (PCMO)
KW - Automotive
KW - Tribology
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464317
SN - 978-9-53510-698-2
DO - https://doi.org/10.5772/46852
SP - 119
EP - 146
PB - INTECH
CY - Rijeka, Croatia
AN - OPUS4-46431
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Würth, Christian
A1 - Geißler, Daniel
A1 - Resch-Genger, Ute
T1 - Quantification of anisotropy-related uncertainties in relative photoluminescence quantum yield measurements of nanomaterials - semiconductor quantum dots and rods
N2 - In order to assess the anisotropy-related uncertainties of relatively determined photoluminescence quantum yields (ΦPL) of molecular emitters and luminescent nanomaterials, we compared ΦPL values measured without and with polarizers using magic angle conditions and studied systematically the dependence of the detected emission intensity on the polarizer settings for samples of varying anisotropy. This includes a dispersion of a spherical quantum dot (QD) with an ideally isotropic emission, a solution of a common small organic dye in a fluid solvent as well as dispersions of elongated quantum dot rods (QDR) with an anisotropic luminescence and a small organic dye in a rigid polymeric matrix, as ideally anisotropic emitter. Our results show that for instruments lacking polarizers, anisotropy-related measurement uncertainties of relative photoluminescence quantum yields can amount to more than 40%, with the size of these systematic errors depending on the difference in emission anisotropy between the sample and the standard.
KW - Photoluminescence
KW - Quantum Yield
KW - Emission Anisotropy
KW - Quantum Dot Rod
KW - Quantum Dot
KW - Dye
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-325240
DO - https://doi.org/10.1515/zpch-2014-0626
SN - 0942-9352
SN - 2196-7156
SN - 0044-3336
SN - 0044-3328
VL - 229
IS - 1-2
SP - 153
EP - 165
PB - Oldenbourg
CY - München
AN - OPUS4-32524
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guehrs, E.
A1 - Schneider, M.
A1 - Günther, Ch. M.
A1 - Hessing, P.
A1 - Heitz, K.
A1 - Wittke, D.
A1 - López-Serrano Oliver, Ana
A1 - Jakubowski, Norbert
A1 - Plendl, J.
A1 - Eisebitt, S.
A1 - Haase, A.
T1 - Quantification of silver nanoparticle uptake and distribution within individual human macrophages by FIB/SEM slice and view
N2 - Quantification of nanoparticle (NP) uptake in cells or tissues is very important for safety assessment. Often, electron microscopy based approaches are used for this purpose, which allow imaging at very high resolution. However, precise quantification of NP numbers in cells and tissues remains challenging. The aim of this study was to present a novel approach, that combines precise quantification of NPs in individual cells together with high resolution imaging of their intracellular distribution based on focused ion beam/ scanning electron microscopy (FIB/SEM) slice and view approaches.
KW - Nanoparticles
KW - FIB/SEM slice and view
KW - Absolute dose
KW - Cellular internalization
KW - Macrophage
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-400626
DO - https://doi.org/10.1186/s12951-017-0255-8
SN - 1477-3155
VL - 15
SP - Article 21, 1
EP - 11
AN - OPUS4-40062
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, X.
A1 - Pauli, Jutta
A1 - Niessner, R.
A1 - Resch-Genger, Ute
A1 - Knopp, D.
T1 - Gold nanoparticle-catalyzed uranine reduction for signal amplification in fluorescent assays for melamine and aflatoxin B1
N2 - A multifunctional fluorescence platform has been constructed based on gold nanoparticle (AuNP)-catalyzed uranine reduction. The catalytic reduction of uranine was conducted in aqueous solution using AuNPs as nanocatalyst and sodium borohydride as reducing reagent, which was monitored by fluorescence and UV-vis spectroscopy. The reaction rate was highly dependent on the concentration, size and dispersion state of AuNPs. When AuNPs aggregated, their catalytic ability decreased, and thereby a label-free fluorescent assay was developed for the detection of melamine, which can be used for melamine determination in milk. In addition, a fluorescent immunoassay for aflatoxin B1 (AFB1) was established using the catalytic reaction for signal amplification based on target-induced concentration change of AuNPs, where AFB1-BSA-coated magnetic beads and anti-AFB1 antibody-conjugated AuNPs were employed as capture and signal probe, respectively. The detection can be accomplished in 1 h and acceptable recoveries in spiked maize samples were achieved. The developed fluorescence system is simple, sensitive and specific, which could be used for the detection of a wide range of analytes.
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347677
DO - https://doi.org/10.1039/c5an01300c
SN - 0003-2654
SN - 1364-5528
VL - 140
IS - 21
SP - 7305
EP - 7312
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-34767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szczerba, Wojciech
A1 - Zukrowski, J.
A1 - Przybylski, M.
A1 - Sikora, M.
A1 - Safonova, O.
A1 - Shmeliov, A.
A1 - Nicolosi, V.
A1 - Schneider, M.
A1 - Granath, T.
A1 - Oppmann, M.
A1 - Straßer, M.
A1 - Mandel, K.
T1 - Pushing up the magnetisation values for iron oxide nanoparticles via zinc doping: X-ray studies on the particle's sub-nano structure of different synthesis routes
N2 - The maximum magnetisation (saturation magnetisation) obtainable for iron oxide nanoparticles can be increased by doping the nanocrystals with non-magnetic elements such as zinc. Herein, we closely study how only slightly different synthesis approaches towards such doped nanoparticles strongly influence the resulting sub-nano/atomic structure. We compare two co-precipitation approaches, where we only vary the base (NaOH versus NH3), and a thermal decomposition route. These methods are the most commonly applied ones for synthesising doped iron oxide nanoparticles. The measurable magnetisation change upon zinc doping is about the same for all systems. However, the sub-nano structure, which we studied with Mössbauer and X-ray absorption near edge spectroscopy, differs tremendously. We found evidence that a much more complex picture has to be drawn regarding what happens upon Zn doping compared to what textbooks tell us about the mechanism. Our work demonstrates that it is crucial to study the obtained structures very precisely when “playing” with the atomic order in iron oxide nanocrystals.
KW - Magnetic nanoparticles
KW - Zinc ferrite
KW - magnetic saturation
KW - Mössbauer
KW - XAFS
KW - Synthesis
KW - XRD
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379583
DO - https://doi.org/10.1039/C6CP04221J
VL - 18
SP - 25221
EP - 25229
PB - RSC Publishing
AN - OPUS4-37958
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Gollwitzer, C.
A1 - Sikora, A.
A1 - Minelli, C.
A1 - Krumrey, M.
A1 - Resch-Genger, Ute
T1 - Effect of fluorescent staining on size measurements of polymeric nanoparticles using DLS and SAXS
N2 - The influence of fluorescence on nanoparticle size measurements using dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) was investigated. For this purpose, two series of 100 nm-sized polymer nanoparticles stained with different concentrations of the fluorescent dyes DY555 and DY680 were prepared, absorbing/emitting at around 560 nm/590 nm and 695 nm/715 nm, respectively. SAXS measurements of these particle series and a corresponding blank control (without dye) revealed similar sizes of all particles within an uncertainty of 1 nm. DLS measurements carried out at three different laboratories using four different DLS instruments and two different laser wavelengths, i.e., 532 nm and 633 nm, revealed also no significant changes in size (intensity-weighted harmonic mean diameter, ZAverage) and size distribution (polydispersity index, PI) within and between the two dye-stained particle series and the blank sample. Nevertheless, a significant decrease of the detected correlation coefficients was observed with increasing dye concentration, due to the increased absorption of the incident light and thus, less coherent light scattering. This effect was wavelength dependent, i.e. only measurable for the dye-stained particles that absorb at the laser wavelength used for the DLS measurements.
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-349684
DO - https://doi.org/10.1039/C5AY02005K
SN - 1759-9660
SN - 1759-9679
VL - 7
IS - 23
SP - 9785
EP - 9790
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-34968
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andrae, K.
A1 - Merkel, Stefan
A1 - Durmaz, V.
A1 - Fackeldey, K.
A1 - Köppen, Robert
A1 - Weber, M.
A1 - Koch, Matthias
T1 - Investigation of the ergopeptide epimerization process
N2 - Ergopeptides, like ergocornine and a-ergocryptine, exist in an S- and in an R-configuration. Kinetic experiments imply that certain configurations are preferred depending on the solvent. The experimental methods are explained in this article. Furthermore, computational methods are used to understand this configurational preference. Standard quantum chemical methods can predict the favored configurations by using minimum energy calculations on the potential energy landscape. However, the explicit role of the solvent is not revealed by this type of methods. In order to better understand its influence, classical mechanical molecular simulations are applied. It appears from our research that 'folding' the ergopeptide molecules into an intermediate state (between the S- and the R-configuration) is mechanically hindered for the preferred configurations.
KW - Ergopeptide
KW - Epimerization
KW - Hybrid monte carlo
KW - Molecular dynamics
KW - Conformation
KW - Quantum mechanics
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324632
DO - https://doi.org/10.3390/computation2030102
SN - 2079-3197
VL - 2
IS - 3
SP - 102
EP - 111
PB - MDPI
CY - Basel
AN - OPUS4-32463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manke, I.
A1 - Kardjilov, N.
A1 - Schäfer, R.
A1 - Hilger, A.
A1 - Grothausmann, R.
A1 - Strobl, M.
A1 - Dawson, M.
A1 - Grünzweig, C.
A1 - Tötzke, C.
A1 - David, C.
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Banhart, J.
T1 - Three-dimensional imaging of magnetic domains with neutron grating interferometry
N2 - This paper gives a brief overview on3D imaging of magnetic domains with shearing grating neutron tomography. We investigated the three-dimensional distribution of magnetic domain walls in the bulk of a wedge-shaped FeSi single crystal. The width of the magnetic domains wasanalyzed at different locations within the crystal. Magnetic domains close to the tip of the wedge are much smaller than in the bulk. Furthermore, the three-dimensional shape of individual domains wasinvestigated. We discuss prospects and limitations of the applied measurement technique.
KW - Neutron imaging
KW - Tomography
KW - Magnetic domains
KW - Grating interferometry
KW - Darkfield imaging
KW - Shearing gratings
KW - Talbot-Lau
KW - Three-dimensional data quantification
KW - Tomographic reconstruction
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-341919
DO - https://doi.org/10.1016/j.phpro.2015.07.057
SN - 1875-3892
VL - 69
SP - 404
EP - 412
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-34191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Büchner, T.
A1 - Drescher, D.
A1 - Merk, V.
A1 - Traub, Heike
A1 - Guttmann, P.
A1 - Werner, St.
A1 - Jakubowski, Norbert
A1 - Schneider, G.
A1 - Kneipp, J.
T1 - Biomolecular environment, quantification, and intracellular interaction of multifunctional magnetic SERS nanoprobes
N2 - Multifunctional composite nanoprobes consisting of iron oxide nanoparticles linked to silver and gold nanoparticles, Ag–Magnetite and Au–Magnetite, respectively, were introduced by endocytic uptake into cultured fibroblast cells. The cells containing the non-toxic nanoprobes were shown to be displaceable in an external magnetic field and can be manipulated in microfluidic channels. The distribution of the composite nanostructures that are contained in the endosomal system is discussed on the basis of surfaceenhanced Raman scattering (SERS) mapping, quantitative laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) micromapping, and cryo soft X-ray tomography (cryo soft-XRT). Cryo soft-XRT of intact, vitrified cells reveals that the composite nanoprobes form intra-endosomal aggregates. The nanoprobes provide SERS signals from the biomolecular composition of their surface in the endosomal environment. The SERS data indicate the high stability of the nanoprobes and of their plasmonic properties in the harsh environment of endosomes and lysosomes. The spectra point at the molecular composition at the surface of the Ag–Magnetite and Au–Magnetite nanostructures that is very similar to that of other Composite structures, but different from the composition of pure silver and gold SERS nanoprobes used for intracellular investigations. As shown by the LA-ICP-MS data, the uptake efficiency of the magnetite composites is approximately two to three times higher than that of the pure gold and silver nanoparticles.
KW - Nanoparticles
KW - SERS
KW - Cell
KW - LA-ICP-MS
KW - X-ray tomography
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371811
DO - https://doi.org/10.1039/c6an00890a
SN - 0003-2654
VL - 141
IS - 17
SP - 5096
EP - 5106
PB - Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-37181
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Winkelmann, Aimo
A1 - Nolze, Gert
A1 - Voss, M.
A1 - Salvat-Pujol, F.
A1 - Werner, W. S. M.
T1 - Physics-based simulation models for EBSD: advances and challenges
N2 - EBSD has evolved into an effective tool for microstructure investigations in the scanning electron microscope. The purpose of this contribution is to give an overview of various simulation approaches for EBSD Kikuchi patterns and to discuss some of the
underlying physical mechanisms.
T2 - EMAS 2015 - 14th European Workshop on MODERN DEVELOPMENTS AND APPLICATIONS IN MICROBEAM ANALYSIS
CY - Portoroz, Slovenia
DA - 03.05.2015
KW - Electron backscatter diffraction
KW - Simulation
KW - Dynamical theory
KW - Kinematic theory
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377469
DO - https://doi.org/10.1088/1757-899X/109/1/012018
VL - 109
SP - 012018-1
EP - 012018-13
AN - OPUS4-37746
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Götschel, S.
A1 - Maierhofer, Christiane
A1 - Müller, Jan P.
A1 - Rothbart, Nick
A1 - Weiser, M.
T1 - Quantitative defect reconstruction in active thermography for fiber-reinforced composites
N2 - Carbon-fiber reinforced composites are becoming more and more important in the production of light-weight structures, e.g., in the automotive and aerospace industry. Thermography is often used for non-destructive testing of These products, especially to detect delaminations between different layers of the composite.
In this presentation, we aim at methods for defect reconstruction from thermographic measurements of such carbon-fiber reinforced composites. The reconstruction results shall not only allow to locate defects, but also give a quantitative characterization of the defect properties. We discuss the simulation of the measurement process using finite element methods, as well as the experimental validation on flat bottom holes.
Especially in pulse thermography, thin boundary layers with steep temperature gradients occurring at the heated surface need to be resolved. Here we use the combination of a 1D analytical solution combined with numerical solution of the remaining defect equation. We use the simulations to identify material Parameters from the measurements.
Finally, fast heuristics for reconstructing defect geometries are applied to the acquired data, and compared for their accuracy and utility in detecting different defects like back surface defects or delaminations.
T2 - 19th World Conference on Non-Destructive Testing 2016
CY - München, Germany
DA - 13.06.2016
KW - Active thermography
KW - Numerical simulation
KW - Time-resolved thermogram
KW - Thermal wave
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366644
UR - https://www.wcndt2016.com/Programme/show/Th-4-C-4
VL - 2016
SP - Th.4.C.4-1
EP - Th.4.C.4-10
AN - OPUS4-36664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spranger, Holger
A1 - Beckmann, Jörg
A1 - Boehm, Rainer
T1 - THz-ToF techniques for the detection of inherent discontinuities in dielectric materials based on a SAFT – and an optical layer reconstruction algorithm
N2 - Electromagnetic waves with frequencies between 0.1 and 10 THz are described as THz-radiation (T-ray). The ability to penetrate dielectric materials makes T-rays attractive to reveal discontinuities in polymer and ceramic materials. THz-Time Domain Spectroscopy Systems (THz-TDS) are available on the market today which operates with THz-pulses transmitted and received by optically pumped semiconductor antennas. In THz-TDS the travelling time (ToF) and shape of the pulse is changed if it interacts with the dielectric material and its inherent discontinuities.
A tomogram of the object under the test can be reconstructed from time of flight diffraction (ToFD) scans if a synthetic focusing aperture (SAFT) algorithm is applied. Otherwise, planar discontinuities like cracks in plastics or delaminated layers in composites can be abstracted as layers located at any angle in relation to the outer sample surface direction. A tomogram from the scanned sample can then be reconstructed in case the interactions of electromagnetic pulses with the existing inherent interfaces are detectable and a model is assumed which describes the device under the test as multilayer structure composed of thin layers with different dielectric properties.
A short description of both the SAFT – and Optical Layer algorithm for the reconstruction of the inherent structure is initially given. Measurements on representative samples with a variety of artificially produced small and large scale. Reconstructed tomograms are presented to discuss and evaluate the benefits and limits of the two different reconstruction approaches.
T2 - 19th World Conference on Non-Destructive Testing 2016
CY - Munich, Germany
DA - 13.06.2016
KW - THz SAFT Optical layer reconstruction
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365866
SN - 978-3-940283-78-8
VL - 158
SP - 1
EP - 10
AN - OPUS4-36586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Illerhaus, Bernhard
A1 - Maenz, S.
A1 - Bischoff, S.
A1 - Bungartz, M.
A1 - Bossert, J.
A1 - Kunisch, E.
A1 - Kinne, R.
ED - Maenz, S.
T1 - Micro computer tomography (μCT) set-up for long-term serial measurements, image evaluation, and subsequent compressive strength tests on frozen sheep vertebrae for osteoporosis research
N2 - Injection of poly(methyl methacrylate) cements, one standard Treatment for osteoporotic vertebral body fractures, may lead to critical loads and subsequent fractures in adjacent vertebral bodies. Biodegradable calcium phosphate cements (CPC) with bioinductive growth factors may be an alternative, since they have a Young’s modulus comparable to that of cancellous bone. Non-destructive tests with μCT and quantitative Image evaluation are used to assess new bone growth and material resorption following intravertebral injection of CPC. Immediate deep-freezing of excised bone prevents shrinkage or tissue disintegration and the samples have to be kept frozen for all following steps, including transport, μCT measurements, and subsequent biomechanical tests. Here we will report on a set-up to preserve the frozen state of the material and allow stable long-term serial μCT measurements. In addition, the image processing technique for the evaluation of bone growth and selected results on subsequently carried out compressive strength tests will be presented.
T2 - WCNDT2016
CY - München, Germany
DA - 13.6.2016
KW - Computed tomography
KW - Osteoporosis
KW - CT
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366410
UR - https://www.ndt.net/?id=19382
VL - BB 158
SP - 1
EP - 7
PB - DGZfP
CY - Berlin
AN - OPUS4-36641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pavlovic, Mato
A1 - Müller, Christina
A1 - Heckel, Thomas
A1 - Zoёga, Andreas
T1 - Reliability analysis of the ultrasonic inspection system for the inspection of hollow railway axles
N2 - Axles are safety critical train components that are subjected to significant cyclic loading during operation. If the crack is initiated in the axle, cyclic loading will lead to crack propagation. To maintain structural integrity, axles must be periodically inspected for fatigue cracks in the material. Deutsche Bahn uses mechanized ultrasonic inspection system to inspect hollow railway axles. The inspections are performed from the bore surface, using several conventional transducers with different incident angles, inspecting the axle along the entire length. As with the every safety critical system, the reliability of these inspections must be determined with regard to their flaw detection capabilities. Traditionally this is done according to the relevant standards for railway vehicles. To investigate the capability of the NDT system more thoroughly, we want to evaluate the capability of the inspection system to detect flaws by means of probability of detection (POD) curves. It will be shown that other parameters, beside the size of the crack, for example crack position in the axle, influence the detection of the crack. The influence of these parameters was evaluated using ultrasonic simulation. The evaluation served as an input for the manufacturing of the flaws in the real scale axle. Once these axles are inspected and the data evaluated, using data from both measurement and simulation, we will express the POD of the crack as function of influencing parameters using the multiparameter POD model.
T2 - 19th Wolrd Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - POD
KW - Railway
KW - Axle
KW - Safety
KW - Reliability
KW - Ultrasonics
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366996
VL - 2016/158
SP - Tu.3.D.5
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-36699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Daschewski, Maxim
A1 - Bartusch, Jürgen
A1 - Schadow, Florian
A1 - Dohse, Elmar
A1 - Kreutzbruck, Marc
A1 - Weise, Matthias
A1 - Beck, Uwe
T1 - Novel air-coupled ultrasonic transducer combining the thermoacoustic with the piezoelectric effect
N2 - In recent years, there has been an increasing industrial demand for one-sided inspection of various structures by means of air-coupled ultrasonic technique. Lightweight structures based on carbon-fibre-reinforced polymers may have very complex shapes, making air-coupled transmission difficult or even impossible. The inspection of concrete structures is another example where one-sided inspection is required.
To address these challenges a new type of transducer for air-coupled pulse-echo inspection was developed, which unites two principles: thermoacoustic emission and piezoelectric reception. The thermoacoustic emitter is a titanium electrode with a thickness of several tens of nanometer. This electrode was deposited onto charged cellular polypropylene, which serves as a piezoelectric receiver. The thermoacoustic transmission is based on a transformation of the thermal energy of an electrically heated electrode into the acoustic energy of an ultrasonic wave. Thermoacoustic emitters provide resonance-free behaviour and thus extremely broadband pulses. Charged cellular polypropylene is piezoelectric due to the polarization of its cells and it is well matched to air, with a Young modulus in the order of magnitude of MPa. In this contribution we present some pulse-echo measurements with the first prototypes of the combined thermoacoustic-piezoelectric transducer.
T2 - World Conference of Non-Destructive Testing
CY - Munich, Germany
DA - 13.6.2016
KW - Thermoacoustic
KW - Piezoelectric
KW - Ultrasonic transducer
KW - Ferroelectret
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367151
VL - 158
SP - Mo.1.F.4, 1
EP - 6
AN - OPUS4-36715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pavlovic, Mato
A1 - Müller, Christina
A1 - Ronneteg, U.
T1 - Reliability Analysis of the Phased-Array Ultrasonic System used for the Inspection of Friction Stir Welds
N2 - The canister for the permanent storage of spent nuclear fuel used by SKB in Sweden consists of a cast iron insert surrounded by a five centimetre thick shell of copper. It is a safety critical component and in order to secure long-term structural integrity non-destructive methods are used to inspect 100% of the volume of each canister, before it is disposed of in the repository. One of the critical components that requires inspection is a sealing weld, joining the copper tube and the lid. The friction stir weld is inspected using an ultrasonic phased array system. The area of the weld is inspected with several inspection channels with different angles and varying coverage. To make sure that no defects that might occur in the weld are overseen, the reliability of the inspection must be quantified. The reliability of NDT is usually quantified with the probability of detection curves. The influence of the parameters that might influence the POD of the flaws in the weld is investigated analysing the experimental results, as well as with a help of a numerical simulation of the inspection.
T2 - 19th Wolrd Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - NDT
KW - Ultrasonic
KW - Reliability
KW - POD
KW - Copper
KW - FSW
KW - JLH
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366982
VL - 2016/158
SP - We.4.E.5
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-36698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schlick-Hasper, Eva
A1 - Goedecke, Thomas
A1 - Kraume, M.
T1 - Überdruck in Gefahrgutverpackungen unter normalen Beförderungsbedingungen
N2 - Für die Durchführung einer Dichtheitsprüfung und für die Bewertung des Ergebnisses ist es wichtig, den sich unter Betriebsbedingungen im Prüfobjekt einstellenden Überdruck zu kennen. Entspricht der Prüfüberdruck nicht dem Betriebsüberdruck, so ist es oft erforderlich, die unter Prüfbedingungen gemessenen Leckageraten auf den realen Betriebsüberdruck umzurechnen. Im Bereich der Gefahrgutverpackungen ist jedoch der spätere maximale Betriebsüberdruck nicht genau bekannt. Er hängt für jede einzelne Verpackungsbauart von dem eingefüllten Füllmedium mit seinen spezifischen Stoffeigenschaften, dem Füllgrad sowie den Beförderungsbedingungen, insbesondere der mittleren Transporttemperatur, ab. Es werden Berechnungsansätze vorgestellt, mit denen sich der Überdruck in Gefahrgutverpackungen unter Beförderungsbedingungen rechnerisch ermitteln lässt. Die theoretisch berechneten Überdrücke werden mit Überdruck-Messwerten verglichen, die mit verschiedenen Füllmedien in unterschiedlichen Verpackungsbauarten ermittelt wurden.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Gefahrgutverpackungen
KW - Überdruck
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-332563
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Di.3.B.1, 1
EP - 13
AN - OPUS4-33256
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Myrach, Philipp
A1 - Maierhofer, Christiane
A1 - Reischel, Mercedes
A1 - Rahammer, M.
A1 - Holtmann, N.
T1 - Untersuchung der Auflösungsgrenzen der Lockin-Thermografie zur Prüfung von Faserverbundwerkstoffen
N2 - Aktive Thermografie mit Lockin-Anregung stellt ein berührungsfreies und zerstörungsfreies Prüfverfahren dar, welches insbesondere auch die Prüfung von kohlenstofffaserverstärkten Kunststoffen ermöglicht. Um eine Standardisierung dieses Verfahrens voranzubringen, wurden im Rahmen eines Forschungsprojektes umfangreiche Untersuchungen zur Validierung des Verfahrens durchgeführt.
Dabei wurden unter anderem der Einfluss der spektralen Empfindlichkeit verschiedener Kamerasysteme, unterschiedlicher Lagenaufbauten bei CFK-Probekörpern und der Einfluss einer Phasenverschiebung zwischen dem Anregungssignal und der Detektion der Thermografiebilder untersucht.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Aktive Thermografie
KW - Lockin-Thermografie
KW - CFK
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309259
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Di.3.C.3, 1
EP - 10
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-30925
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kreutzbruck, Marc
A1 - Bauer, P.
A1 - Caspers, F.
A1 - Heck, S.
A1 - Müller, F.
A1 - Pohl, Rainer
A1 - Scheuerlein, C.
A1 - Sickert, Roland
A1 - Maierhofer, Christiane
A1 - Brackrock, Daniel
T1 - Sensoren für Verbunddrähte aus Niob-Titan und Kupfer
N2 - Der Large Hadron Collider (LHC) des europäischen Kernforschungszentrums CERN ist einer der weltweit größten und leistungsfähigsten Teilchenbeschleuniger. Um den Teilchenstrahl auf seiner Kreisbahn zu halten, werden mit Hilfe supraleitender Spulen sehr starke Magnetfelder erzeugt. Die hierzu benötigten hohen Ströme werden über Verbunddrähte aus Niob-Titan und Kupfer geleitet.
Die Drähte werden u.a. durch Ultraschallschweißungen miteinander verbunden. Eine mangelhafte Verbindung kann zur Erwärmung der Kontaktstelle und in Folge davon zum Zusammenbruch der Supraleitung führen. Auf Anfrage des CERN wurden an der BAM Untersuchungen zur Prüfbarkeit solcher Verbindungen bei Umgebungstemperatur durchgeführt. Es gelang, für einen Verbindungstypen einen Wirbelstromsensor für eine manuelle Prüfung zu entwickeln. Ein Prototyp des Sensors befindet sich beim CERN in der praktischen Erprobung. Das Sensorprinzip sowie Prüfergebnisse aus Labor und Praxis werden vorgestellt.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Ultraschallprüfung mit Matrix-Sensoren
KW - Aktive Thermografie
KW - Gabelsensor
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-319785
SN - 978-3-940283-61-0
VL - 148
SP - 1
EP - 12
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31978
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gravenkamp, Hauke
A1 - Song, C.
T1 - Innovative numerische Methoden zur Simulation geführter Ultraschallwellen
N2 - Geführte Ultraschallwellen bieten eine Vielzahl von Einsatzmöglichkeiten in der Zerstörungsfreien Prüfung, der Zustandsüberwachung sowie der Materialcharakterisierung. Insbesondere für Rohrleitungen und ausgedehnte Plattenstrukturen ist eine Vielzahl von auf geführten Wellen basierenden Verfahren in der Entwicklung und teilweise bereits im Einsatz. Aufgrund des komplexen Ausbreitungsverhaltens geführter Wellen werden numerische Verfahren (etwa die Finite Elemente Methode (FEM) oder die Randelementemethode (BEM)) zur Simulation der Wellenausbreitung sowie der Wechselwirkung mit Defekten in Wellenleitern angewendet. Diese Methoden sind für große Strukturen extrem rechenintensiv und umständlich in der Anwendung. Ein ungleich effizienteres Verfahren wurde kürzlich von den Autoren auf Grundlage der Scaled Boundary Finite Element Method entwickelt. Ein semi-analytischer Ansatz erlaubt die Modellierung beliebig ausgedehnter Strukturen bei extrem kurzen Rechenzeiten. Die Wechselwirkung geführter Wellen mit Rissen kann auf besonders elegante und exakte Weise beschrieben werden. Mit dieser Methode können die komplexen Vorgänge in Wellenleitern innerhalb weniger Sekunden modelliert werden.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.04.2014
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313610
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Poster 66, 1
EP - 6
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-31361
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
A1 - Gaal, Mate
A1 - Müller, Christina
A1 - Fahlbruch, B.
A1 - Schombach, D.
T1 - Einfluss des Zeitdrucks auf die manuelle Ultraschallprüfung. Untersuchung zu menschlichen Faktoren auf die Ergebnisse zerstörungsfreier Prüfungen
N2 - Die übergeordnete Zielsetzung unserer Untersuchung bestand darin,
am Beispiel von Prüfungen mit Ultraschall eine belastbare Aussage zum Einfluss der Arbeitsbedingungen des Prüfers auf die Qualität der Ergebnisse von zerstörungsfreien Prüfungen zu ermitteln und Möglichkeiten zur Minimierung ungünstiger Einflussfaktoren aufzuzeigen.
Der Schwerpunkt der Untersuchung wurde auf die manuelle Ultraschallprüfung gelegt und der Faktor 'Zeitdruck' (in drei Stufen variiert) als die zu variierende physische Einflussgröße gewählt. Die Variation des Faktors Zeitdruck wurde gemäß dem Prozessmodell von der Erhebung psychologischer Faktoren, die das Individuum und die Organisation beschreiben, begleitet.
Die Ultraschallprüfungen erfolgten mit zehn Prüfern am Großbehälter und an Vergleichskörpern mit eingebrachten Testfehlern (Nuten, Risse). Die ausgewählten Fehler waren typisch für Prüfaufgaben, die bei wiederkehrenden Ultraschallprüfungen in Kernkraftwerken von den Prüfern zu lösen sind. Die Prüfaufgabe bestand darin, die in den vorgegebenen Prüfabschnitten vorhandenen Reflektoren aufzufinden und deren Amplituden, Ortskoordinaten und Längenerstreckungen zu ermitteln. Als Bewertungsmaßstab für die Qualität der Prüfaussage und für den Einfluss des menschlichen Faktors diente die Präzision der gemessenen Werte. Die Ergebnisse zeigen einen hohen Einfluss des menschlichen Faktors auf das Prüfergebnis und eine Einwirkung des Zeitdrucks besonders auf die Präzision der Messwerte. Hierbei war die Wirkung des individuell wahrgenommenen Zeitdrucks zusammen mit der psychischen Arbeitsbeanspruchung signifikant. Es wurde unter anderem herausgearbeitet, dass durch eine gute Vorbereitung auf die Prüfung, z.B. durch die sorgfältige Einweisung und ein vorgeschaltetes Fertigkeitstraining an Vergleichskörpern, die Zuverlässigkeit der Prüfergebnisse verbessert werden kann.
Insgesamt hatte der Faktor 'Organisation' neben der 'Erfahrung' einen hohen Einfluss auf das Leistungsvermögen der Prüfer.
Die Projektergebnisse wurden im Abschlussbericht des Forschungsvorhabens SR2514 dargestellt, es wurden drei Empfehlungen zur Vorbereitung und Einweisung der Prüfer, zur Stärkung der Verantwortung der Prüfaufsicht und zum 4-Augen-Prinzip formuliert. Die Empfehlungen wurden in der KTA- Regel 3201.4 'Komponenten des Primärkreises von Leichtwasserreaktoren; Teil 4: Wiederkehrende Prüfungen und Betriebsüberwachung (RÄE Fassung 2010-11)', umgesetzt.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Human factors
KW - ZfP
KW - Ultraschallprüfung
KW - UT
KW - Zeitdruck
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-251610
UR - http://jt2011.dgzfp.de/Portals/jt2011/BB/mi2c3.pdf
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Mi.2.C.3)
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-25161
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Boehm, Rainer
A1 - Brackrock, Daniel
A1 - Kitze, Jessica
A1 - Brekow, Gerhard
A1 - Kreutzbruck, Marc
A1 - Heinrich, W.
T1 - Ultraschalluntersuchungen an einem Turbinenradscheibentestkörper mit Sägezahn-Arrays
N2 - - Besondere Anforderungen der Prüfaufgabe
- Elektronischer Scan für Tandemtechnik bzw. Pitch - Catch Technik
- Der ebene Winkelprüfkopf, ein besonderer Gruppenstrahler (PA)
- Charakterisierung des Prüfkopfes, Verifikation durch Messung
- Messungen am Turbinenradscheibentestkörper
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Ultraschallprüftechnik
KW - Phased array
KW - Prüfkopfentwicklung
KW - Turbinenradscheiben
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-252085
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.1.A.3)
SP - 1
EP - 21
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25208
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Taffe, Alexander
A1 - Kind, Thomas
A1 - Stoppel, Markus
A1 - Kurz, J. H.
T1 - OSSCAR-Bauwerkscanner: Automatisierte Datenaufnahme von Radar, Ultraschall und Wirbelstrom an Spannbetonbauteilen mit bildgebender Darstellung der inneren Konstruktion
N2 - Bereits seit vielen Jahren stehen Anwendern der zerstörungsfreien Prüfung im Bauwesen (ZfPBau) zuverlässige Geräte für Radar-, Wirbelstrom- und Ultraschallmessungen an Betonbauteilen zur Verfügung. Doch erst die Kombination dieser drei Verfahren an einer Messfläche erlaubt den maximalen Informationsgewinn über die innere Konstruktion von Stahlbeton- und Spannbetonbauteilen. Mit dem OSSCAR-Bauwerkscanner wurden diese drei Verfahren erstmals zur kombinierten
und automatisierten Datenaufnahme an einem Scannerrahmen und unter einer Software vereint. Die Ergebnisse werden bildgebend in frei wählbaren Schnitten dargestellt, was eine Rekonstruktion von Bauteilen erlaubt, für die keine Planunterlagen vorliegen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Zerstörungsfreie Prüfung im Bauwesen
KW - Bauwerkscanner
KW - Brückenprüfung
KW - Ultraschall
KW - Radar
KW - Wirbelstrom
KW - Kombination
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253767
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Mi.3.B.1)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25376
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kitze, Jessica
A1 - Boehm, Rainer
A1 - Brackrock, Daniel
A1 - Montag, Hans-Joachim
A1 - Völz, Uwe
A1 - Brekow, Gerhard
A1 - Kreutzbruck, Marc
T1 - SAFT-Rekonstruktion und 3D Lokalisation aus Ultraschallmessungen mit Matrix- und Linear-Arrays in Tauchtechnik
N2 - Die Kombination der Synthetic Aperture Focusing Technique (SAFT) mit der Tauchtechnik stellt eine besondere Herausforderung dar. Zwei für SAFT notwendige Bedingungen – die große Schallbündeldivergenz und die Kenntnis über den Ort des Senders bzw. des Empfängers, der für die phasenrichtige Überlagerung der Echosignale genau bekannt sein muss – lassen sich einfach erfüllen, wenn kleine, fast punktförmige Sensoren direkt auf der Oberfläche des Prüfobjektes ankoppeln. Diese Anordnung ist in der Regel nicht vereinbar mit den praktischen Ansprüchen an die Signalqualität und die Flexibilität der Prüftechnik.
Werden jedoch Prüfköpfe mit üblichen Abmessungen und zudem noch mit Vorlaufstrecken verwendet, dann ist die Bestimmung der Sensororte und der Schalllaufwege durch die brechende Fläche nicht mehr trivial, wenn man die für SAFT geforderte Genauigkeit in Rechnung stellt.
Etwas anderes, aber ein im Prinzip einfacher Weg zur räumlichen Lokalisation von Echoquellen ist die Auswertung des 2D Sektorscans eines Matrixarrays und dessen dreidimensionale Darstellung. Durch gezielte Steuerung des Arrays gelingt auf einfache Weise die ortsrichtige Zuordnung.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Matrix-Array
KW - Linear-Array
KW - SAFT-Rekonstruktion in Tauchtechnik
KW - Räumliche Darstellung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-252788
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.3.A.2)
SP - 1
EP - 11
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25278
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Völz, Uwe
A1 - Mrasek, Heinz
A1 - Heckel, Thomas
T1 - Querfehlerprüfung an anisotropen Engspaltschweißnähten mit Gruppenstrahlern
N2 - Die Prüfung von anisotropen Schweißnähten auf Querfehler stellt auch heute noch eine Herausforderung für die Ultraschallprüfung dar. Das gilt insbesondere für das Auffinden kleiner rissartiger Fehlstellen in einer unbeschliffenen Wurzel. Ursachen dafür sind zum einen das ausgeprägte Beugungs-, Streuungs- und Reflexionsverhalten solcher Nähte und zum anderen die störenden Formanzeigen aus dem Wurzelbereich, die sicher von den Fehlstellen unterschieden werden müssen, um Fehlinterpretationen bei der Bewertung der Anzeigen zu vermeiden.
In der vorliegenden Arbeit werden an einer 85 mm dicken und 6 bis 10 mm breiten Engspaltschweißnaht mit stängelkristalliner Struktur rissartige Testfehler in Form erodierter Nuten untersucht. Die 2 und 4 mm tiefen Nuten sind mit 5 mm Länge kürzer als die Wurzelbreite. Die Wurzel ist nicht beschliffen und hat eine Überhöhung von ca. 2 mm. Ziel ist es, die Fehlstellen von den Form- und Gefügeanzeigen
zu unterscheiden und sicher zu detektieren. Eine Größenbestimmung ist
nicht vorgesehen.
Durch den Einsatz der Gruppenstrahlertechnik ist es möglich, optimale Einschallparameter zu finden, mit denen diese Aufgabe gelöst werden kann. Es werden zwei azimutal schwenkende lineare Gruppenstrahlerprüfköpfe mit Vorsatzkeil in SE-Technik verwendet, die so auf beiden Seiten der Schweißnaht angeordnet sind, dass sich ihre Schallfelder unabhängig von der Einschallrichtung in der Schweißnahtwurzel überlagern. Damit ist es möglich, optimale Einschallwinkel für das Prüfproblem zu finden und in einer Prüffahrt gleichzeitig in beiden Einschallrichtungen längs der Schweißnaht zu prüfen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Ultraschall
KW - Gruppenstrhaler
KW - Anisotropie
KW - Austenit
KW - Nickellegierung
KW - Querfehler
KW - Schweißnaht
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-252777
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (P49)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25277
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Heckel, Thomas
A1 - Boehm, Rainer
A1 - Gohlke, Dirk
T1 - Optimierung von Ultraschall-fokusprüfköpfen beim Einsatz an stark gekrümmten Oberflächen
N2 - Bei der Prüfung von gekrümmten Bauteilen in Tauchtechnik muss man die Veränderung des Schallfeldes durch die Form der Oberfläche berücksichtigen. Insbesondere bei hochauflösenden Ultraschallprüfungen mit Fokusprüfköpfen kommt es hierbei zu drastischen Verzerrungen des Schallfeldes.
Diese Verzerrungen sind bei der Empfindlichkeitseinstellung sowie bei der Auslegung von Fokuspunkt- und Spurabstand zu berücksichtigen, um eine ausreichende Prüfempfindlichkeit zu erreichen. Es werden Beispiele von Simulationsrechnungen an typischen Prüfanordnungen vorgestellt.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Fokusprüfköpfe
KW - Gekrümmte Oberflächen
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253841
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Poster 62)
SP - 1
EP - 5
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25384
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlisch, Stephan
A1 - Heckel, Thomas
A1 - Sondermann, F.
T1 - Bildgebende Ultraschallhandprüfeinrichtung für die Ausbildung
N2 - Um den vermehrten Einsatz von mechanisierten Prüfeinrichtungen bei der Ultraschallprüfung in der Ausbildung Rechnung zu tragen, ist es wünschenswert, dieses Themenfeld bereits zu einem frühen Zeitpunkt in die Ultraschallkurse zu integrieren. Aus diesem Grund wurde für die Ausbildung bei der DGZfP in Zusammenarbeit mit der BAM ein teilmechanisiertes Ultraschall-Prüfsystem entwickelt.
Das System basiert auf einem handelsüblichen Ultraschallgerät für die Handprüfung und einem Netbook-Computer. Die berührungslose Positionserfassung wird über den Blenden-Ausgang des Ultraschallgerätes getriggert und die Daten werden mittels Infrarot- und Bluetoothtechnik übertragen. Dies ermöglicht einen kompakten und portablen Aufbau mit kurzen Einrichtzeiten, der sich im Rahmen einer Lehrveranstaltung effektiv einsetzen lässt. Die Ergebnisdarstellung erfolgt mit C-Bildern.
An einfachen Übungsstücken können die Kursteilnehmer, dicht an die Handprüfung angelehnt, die Methoden und Randbedingungen einer mechanisierten Prüfung erfahren.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Ultraschallprüfsystem
KW - Ultraschallprüfung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253826
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Poster 89)
SP - 1
EP - 4
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25382
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Pittner, Andreas
A1 - Fabry, Çağtay
T1 - Abschlussbericht IGF 17.923 N: "Sensorgestütztes MSG-Engspaltschweißen von Feinkornstählen mit modifizierter Prozessführung im Dickblechbereich"
N2 - Die im Forschungsvorhaben erzielten Ergebnisse zeigen konkrete technische Lösungen für die automatisierte Anwendung des MSG Engspaltschweißen, sowohl mittels optischer als auch prozessorientierter Sensorik, und sprechen damit ein breites Spektrum möglicher Anwender, insbesondere KMU, an.
Die Seitenführung des Brenners auf Basis der optischen Messgrößen stellt eine robuste und einfach zu implementierende Möglichkeit zur Nahtverfolgung dar. Für die Höhenführung über der Schweißnaht wurde neben der Lösung mittels optischer Messverfahren zusätzlich eine direkt darauf aufbauende Möglichkeit zur Implementierung eines Lichtbogensensors abgeleitet. Das Vorgehen konnte sowohl für Sprühlichtbogenprozesse als auch bei Verwendung von Impulslichtbogenprozessen erfolgreich angewendet werden.
Die zur Sicherstellung eines gleichmäßigen Flankeneinbrandes entwickelte Pendelregelung ist ebenfalls für unterschiedliche Lichtbogenarten einsetzbar und muss vom Anwender auch beim Einsatz einer großen Bandbreite unterschiedlicher Prozessparameter nahezu nicht konfiguriert werden. Neben der im Rahmen der Verfahrensprüfung untersuchten Pendelraupentechnik konnte die Übertragbarkeit des Vorgehens auch auf die Strichraupentechnik anhand von gezielten Schweißversuchen aufgezeigt werden.
Die zunächst auf Basis der optischen Messwerte ausgelegte Füllgradregelung konnte die vorgesehenen Spaltvariationen von 18 bis 24 mm im Rahmen der durchgeführten Verfahrensprüfung ausgleichen. Die Ableitung eines äquivalenten Lichtbogensensors durch Kopplung beider Messprinzipien wurde am Laufzeitende des Vorhabens aufgezeigt, konnte jedoch durch zeitliche Beschränkung nicht für die Verfahrensprüfung berücksichtigt werden.
In Absprache mit dem projektbegleitenden Ausschuss wurde die Entwicklung der Prozessregelung für das Vorhaben auf Schweißungen in Wannenlage und Grundwerkstoffe der Güte S355J2 beschränkt.
Die Qualifizierung des Verfahrens unter Einsatz der beschriebenen Regelalgorithmen nach DIN EN ISO 15614-1 konnte für alle betrachteten Spaltbreiten zwischen 18 und 24 mm anhand einer 50 mm dicken Demonstratorprobe nachgewiesen werden.
KW - Schutzgasschweißen
KW - MSG-Engspaltschweißen
KW - Prozesssteuerung
KW - Lichtbogensensorik
KW - Prozessregelung
KW - GMAW
KW - Narrow gap GMAW
KW - GMAW control
KW - Arc-sensing
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390934
SP - 1
EP - 38
AN - OPUS4-39093
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Luong, Thi Mai Hoa
A1 - Zabel, V.
A1 - Lorenz, W.
A1 - Rohrmann, R.G.
T1 - Non-destructive assessment of the axial stress state in iron and steel truss structures by dynamic measurements
N2 - This paper is concerned with the inverse identification of the stress state in axially loaded slender members of iron and steel truss structures using measured dynamic data. A methodology is proposed based on the finite element model updating coupled with nature-inspired optimization techniques, in particular the particle swarm optimization. The numerical model of truss structures is calibrated using natural frequencies and mode shapes from vibration tests, as well as additional information of the axial forces in selected truss members based on the experimentally identified modal parameters. The results of the identification are the axial forces or corresponding stresses in truss structures and the joint rigidity in relation to pinned and rigid conditions. Attention is given to several examined aspects, including the effects of the axial tensile and compressive forces on the dynamic responses of trusses, mode pairing criteria, as well as modeling assumptions of joints and the use of a joint rigidity parameter. Considering the pairing of modes, it is performed by adapting an enhanced modal assurance criterion that allows the selection of desired clusters of degrees-of-freedom. Thus, information extracted from the measurements related to specific modes is utilized in a more beneficial way. For modeling of joints, the numerical model of a truss structure includes rotational springs of variable stiffness to represent semi-rigid connections. Moreover, a fixity factor is introduced for practical estimation of the joint flexibility. The effectiveness of the proposed methodology is demonstrated by case studies involving simulated and laboratory experimental data.
T2 - X International Conference on Structural Dynamics, EURODYN 2017
DA - 10.09.2017
KW - Axial force
KW - Dynamic test
KW - Model updating
KW - Optimization technique
KW - Truss structures
KW - Modal parameters
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419311
DO - https://doi.org/10.1016/j.proeng.2017.09.447
SN - 1877-7058
VL - 199
SP - 3380
EP - 3385
PB - Elsevier
AN - OPUS4-41931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brackrock, Daniel
A1 - Recknagel, Christoph
A1 - Brekow, Gerhard
A1 - Kreutzbruck, Marc
T1 - Untersuchungen von Glas-Metall Klebverbindungen mit Hilfe von Ultraschall
N2 - Klebverbindungen im modernen Hochbau können helfen, innovative ästhetische Bedürfnisse im Fassadenbau umzusetzen, technologische Verbesserungen zu erreichen, aber auch die Wechselwirkung von Gebäuden mit der Umwelt unter energetischen Aspekten zu optimieren. Aufgrund der hohen sicherheitstechnischen Bedeutung gibt es hohe Anforderungen an die Leistungsfähigkeit, Dauerhaftigkeit und die Gütesicherheit.
Mit einer zerstörungsfreien praxistauglichen Prüftechnik, die eine sichere Überprüfung der Integrität von Glas-Metall Klebverbindungen im Ingenieurhochbau gewährleistet, kann sowohl ein wichtiger Beitrag zur Qualitätssicherung bei der Herstellung von Fassadenelementen aber auch bei der späteren Bauwerksüberwachung im Verlauf der Nutzungsdauer geleistet werden. Für eine Beurteilung der Qualität der Verbundfuge (z.B. bezgl. Standsicherheit) sind dabei Aussagen zur Homogenität der Verbundfuge, zum adhäsiven und kohäsiven Verbundverhalten gefordert. Hierzu besteht aktuell insbesondere Bedarf an zerstörungsfreien praxisgerechten, hoch ortsauflösenden und möglichst bildgebenden Untersuchungsverfahren.
Es wird mit einem Matrixarray und mit konventionellen Winkelprüfköpfen eine Prüftechnik vorgestellt, mit der die Wechselwirkung zwischen Ultraschallwelle und Fehlstelle in der Klebefuge untersucht wird. Hierbei ist das erste Untersuchungsziel, mit einer angepassten Ultraschall-Prüftechnik mögliche Inhomogenitäten oder Schädigungsstellen in der geklebten Glas-Metall Verbindung zu detektieren.
Über diese qualitativen Aussagen hinaus werden weiterführende Informationen über die flächenhafte Ausdehnung und den Ort einer mangelnden Klebung ermittelt. Dazu werden die Messwerte zusammen mit den Positionen des Ultraschallprüfkopfs aufgezeichnet. Mit Hilfe einer bildhaften Auswertung der gemessenen Ultraschallechos in Abhängigkeit vom Prüfkopfort werden die Möglichkeiten einer detaillierten Integritätsanalyse der Glas-Metall Klebschicht dargestellt. In diesem Beitrag werden experimentelle Prüfergebnisse vorgestellt, die im Sinne einer Verfahrensvalidierung an einem speziellen Beispielprobekörper zur Nachstellung einer SSG-Verglasung (ermittelt wurden und die Detektion fehlerhafter Klebestellen in einer Glas-Metall-Klebverbindung zum Ziel haben.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331181
UR - https://www.ndt.net/?id=17428
SN - 978-3-940283-61-0
VL - 148
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-33118
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlick-Hasper, Eva
A1 - Seidler, Oliver
A1 - Goedecke, Thomas
A1 - Kraume, M.
T1 - Helium leak testing of dangerous goods packagings
N2 - The International Dangerous Goods Regulations prescribe the immersion under water method (“bubble test”) as standard method for the leakproofness test of dangerous goods packagings. But this test procedure acts as a test method for leak localisation, not for quantitative leakage rates measurement. Additionally, the sensitivity in detecting leaks of small diameters is restricted, depending on the test liquid and the test pressure. The bubble test is not suitable for a comparison with quantitative limit leakage rates based on realistic transport conditions. This is especially important when estimating the risk of the formation of an explosive atmosphere during the intercontinental carriage of dangerous goods packagings in freight containers. To compare measured leakage rates with limit leakage rates, a quantitative leak testing procedure is required. Therefore a new approach for dangerous goods packagings is implemented: The pressure technique by accumulation using Helium as a tracer gas. This work presents the test equipment necessary for the quantitative measurement of Helium leakage rates through closures of different kinds of dangerous goods packagings. The essential steps to achieve good repeatable results are: A controlled Helium filling process to reach a defined test pressure in the test sample, a sufficient homogenisation of the Helium-air-mixture inside the test sample and the ensuring of a constant pressure level of the test sample during the test. The Helium loss rate of the accumulation chamber has to be measured separately to receive a correction factor for the measured leakage rates. Different constructional measures are introduced to prevent a disturbing influence of the Helium leakage rate of the filling valves on the measurement results. Methods to estimate the disturbing effect of Helium permeation through permeable parts of the test sample are also presented. As a supporting method for the experimental investigations the Helium sniffer test can be applied. This practical application-oriented advice can enable other users to establish a pressure technique by accumulation for their own technical field.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Überdruckverfahren
KW - Gefahrgutverpackungen
KW - Dichtheit
KW - Helium
KW - Dangerous goods packagings
KW - Leakproofness
KW - Helium
KW - Pressure technique
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371376
UR - http://ndt.net/?id=19785
SN - 1435-4934
VL - 21
IS - 7
SP - 1
EP - 10
PB - NDT.net
CY - Kirchwald
AN - OPUS4-37137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiedensohler, A.
A1 - Wiesner, A.
A1 - Weinhold, K.
A1 - Birmili, W.
A1 - Herrmann, M.
A1 - Merkel, M.
A1 - Müller, T.
A1 - Pfeifer, S.
A1 - Schmidt, A.
A1 - Tuch, T.
A1 - Velarde, F.
A1 - Quincey, P.
A1 - Seeger, Stefan
A1 - Nowak, A.
T1 - Mobility particle size spectrometers: Calibration procedures and measurement uncertainties
N2 - Mobility particle size spectrometers (MPSS) belong to the essential instruments in aerosol science that determine the particle number size distribution (PNSD)in the submicrometer size range. Following calibration procedures and target uncertainties against standards and reference instruments are suggested for a complete MPSS quality assurance program: a) calibration of the CPC counting efficiency curve (within 5% for the plateau counting efficiency; within 1 nm for the 50% detection efficiency diameter), b) sizing calibration of the MPSS, using a certified polystyrene latex (PSL) particle size standard at 203 nm (within 3%), c) intercomparison of the PNSD of the MPSS (within 10% and 20% of the dN/dlogDP concentration for the particle size range 20 – 200 nm and 200 to 800 nm, respectively), and d) intercomparison of the integral PNC of the MPSS (within 10%). Furthermore, following measurement uncertainties have been investigated: a) PSL particle size standards in the range from 100-500nm match within 1% after sizing calibration at 203 nm. b) Bipolar diffusion chargers based on the radioactive nuclides Kr85, Am241 and Ni63 and a new ionizer based on corona discharge follow the recommended bipolar charge distribution, while soft X-ray-based charges may alter faster than expected. c) The use of a positive high voltage supply show a 10% better performance than a negative one. d) The intercomparison of the integral PNC of an MPSS against the total number concentration is still within the target uncertainty at an ambient pressure of approximately 500 hPa.
KW - Measurement uncertainties
KW - Mobility particle size spectrometer (MPPS)
KW - Condensation particle counter (CPC)
KW - Calibration
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425060
DO - https://doi.org/10.1080/02786826.2017.1387229
SN - 1521-7388
VL - 52
IS - 2
SP - 146
EP - 164
PB - Tailor & Francis
CY - USA
AN - OPUS4-42506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Swaraj, S.
A1 - Dietrich, Paul
A1 - Unger, Wolfgang
T1 - Simultaneous surface and bulk sensitive XAS measurements of magnetic particle clusters
N2 - Magnetic iron oxide nanoparticle clusters (mnpc) coated with organic stabilizers were investigated using scanning transmission x-ray microscopy (STXM). Simultaneous surface and bulk sensitive Fe L3 edge absorption spectra, obtained using a photomultiplier tube and a channeltron, were used to detect subtle changes in the oxidation state in the surface and bulk of Iron Oxide mnpc.
The effectiveness of this mode of STXM operation is demonstrated for These nanoparticle clusters.
T2 - X-Ray Microscopy Conference 2016 (XRM 2016)
CY - Oxford, UK
DA - 15.08.2016
KW - Scanning transmission x-ray microscopy (STXM)
KW - Magnetic nanoparticles
KW - Fe L3 edge absorption spectra
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435907
UR - http://iopscience.iop.org/article/10.1088/1742-6596/849/1/012014/meta
DO - https://doi.org/10.1088/1742-6596/849/1/012014
VL - 849
SP - 012014, 1
EP - 012014, 4
PB - IOP Publishing
AN - OPUS4-43590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Lehmann, Jens
A1 - Burkert, Andreas
T1 - KorroPad - Beurteilung der Korrosionsbeständigkeit von Oberflächen nichtrostender Stähle
N2 - Mit dem KorroPad Verfahren ist es dem Anwender möglich den Zustand der Passivschicht nichtrostender Stähle auf sehr einfache und schnelle Weise einschätzen zu können. Das Verfahren eignet sich dazu, den Grad der Passivität in Abhängigkeit der Umgebungsbedingungen und der Zeit nachzuvollziehen. Dies ermöglicht dem Anwender und Verarbeiter von nichtrostenden Stählen, die Lagerungsbedingungen und -zeiten einer frisch bearbeiteten Stahloberfläche zu ermitteln, welche für die Ausbildung einer stabilen Passivschicht notwendig sind, bevor diese risikoarm eingesetzt werden kann. Wie die hier dargestellten Beispiele und auch weitere zahlreiche praktische Anwendungen gezeigt haben, eignet sich das KorroPad ebenfalls für die Identifikation kritischer Prozessparameter bei der Verarbeitung nichtrostender Stähle. Mit dem Verfahren lassen sich viele rozessbedingte Einflussfaktoren auf die Oberflächengüte wie auch auf den Werkstoff charakterisieren. Aufgrund der schnellen und einfachen Auswertung der Prüfergebnisse können positive wie auch negative Veränderungen hinsichtlich der Passivschichtstabilität zügig erkannt werden. Dies ermöglicht es dem Anwender schnell zu reagieren, um kritische Einflüsse zu korrigieren und um eine Optimierung von Inhouse-Prozessen durchzuführen. Weitere Einsatzgebiete sind im Bereich der Wareneingangs- und/oder Warenausgangskontrolle denkbar, überall wo es um die Frage der Passivschichtstabilität einer nichtrostenden Stahloberfläche geht.
KW - Korrosionstest
KW - nichtrostender Stahl
KW - Edelstahl Rostfrei
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397049
UR - http://www.ndt.net/article/dgzfp-bau-2016/papers/16.pdf
SN - 1435-4934
VL - 22
IS - 4
SP - Artikel 16
PB - NDT.net
CY - Bad Breising
AN - OPUS4-39704
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaur, I.
A1 - Ellis, L.-J.
A1 - Romer, I.
A1 - Tantra, R.
A1 - Carriere, M.
A1 - Allard, S.
A1 - Mayne-L'Hermite, M.
A1 - Minelli, C.
A1 - Unger, Wolfgang
A1 - Potthoff, A.
A1 - Rades, Steffi
A1 - Valsami-Jones, E.
T1 - Dispersion of nanomaterials in aqueous media: Towards protocol optimization
N2 - The sonication process is commonly used for de-agglomerating and dispersing nanomaterials in aqueous based media, necessary to improve homogeneity and stability of the suspension. In this study, a systematic step-wise approach is carried out to identify optimal sonication conditions in order to achieve a stable dispersion. This approach has been adopted and shown to be suitable for several nanomaterials (cerium oxide, zinc oxide, and carbon nanotubes) dispersed in deionized (DI) water. However, with any change in either the nanomaterial type or dispersing medium, there needs to be optimization of the basic protocol by adjusting various factors such as sonication time, power, and sonicator type as well as temperature rise during the process. The approach records the dispersion process in detail. This is necessary to identify the time Points as well as other above-mentioned conditions during the sonication process in which there may be undesirable changes, such as damage to the particle surface thus affecting surface properties. Our goal is to offer a harmonized approach that can control the Quality of the final, produced dispersion. Such a guideline is instrumental in ensuring dispersion quality repeatability in the nanoscience community, particularly in the field of nanotoxicology.
KW - Dispersion of nanomaterials
KW - Aqueous media
KW - Protocol development
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435886
UR - https://www.jove.com/video/56074
DO - https://doi.org/10.3791/56074
SN - 1940-087X
IS - 130
SP - e560741, 1
EP - e560741, 23
PB - MyJove Corp.
CY - Cambridge, MA, USA
AN - OPUS4-43588
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Hentschel, Manfred P.
A1 - Lange, Axel
A1 - Grothausmann, R.
A1 - Manke, I.
T1 - Application of the DIRECTT algorithm to sub-nanometer electron tomography
N2 - Tomography data obtained from transmission electron microscopes are especially attractive due to their unrivaled spatial resolution in the nanometer range or even less, but they require enormous efforts in sample preparation and suffer from a diverse accumulation of experimental restrictions, which unavoidably result in fundamental reconstruction artifacts. These restrictions refer to: partial opacity, a limited view (limited angle or missing wedge), very few angles (with respect to the detector size), limited to a region of interest (ROI; due to the sample size), variable angular increments as well as sample degradation due the interactions with the electron beam. An advanced version of the DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm proves to cope with most of these severe deviations from ideal CT measuring conditions. However, careful data preprocessing is required in order to exploit the capabilities of the algorithm.
Nanometer sized Ruthenium catalyst particles for fuel cell applications are 3D imaged at a few Ångström resolution in order to estimate their partial free surface on carbon black supports, which rule the efficiency of the catalytic activity.
Comparisons of DIRECTT reconstructions to the conventional filtered back projection, prove the significant improvements.
T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Electron tomography
KW - Computed tomography
KW - Reconstruction algorithms
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243577
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (Tu.3.3)
SP - 1
EP - 6
PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, Sascha
A1 - Breithaupt, Mathias
A1 - Krebber, Katerina
T1 - Distributed humidity sensing in PMMA optical fibers at 500 nm and 650 nm wavelengths
N2 - Distributed measurement of humidity is a sought-after capability for various fields of application, especially in the civil engineering and structural health monitoring sectors. This article presents a method for distributed humidity sensing along polymethyl methacrylate (PMMA) polymer optical fibers (POFs) by analyzing wavelength-dependent Rayleigh backscattering and attenuation characteristics at 500 nm and 650 nm wavelengths. Spatially resolved humidity sensing is obtained from backscatter traces of a dual-wavelength optical time domain reflectometer (OTDR). Backscatter dependence, attenuation dependence as well as the fiber length change are characterized as functions of relative humidity. Cross-sensitivity effects are discussed and quantified. The evaluation of the humidity-dependent backscatter effects at the two wavelength measurements allows for distributed and unambiguous measurement of relative humidity. The technique can be readily employed with low-cost standard polymer optical fibers and commercial OTDR devices.
KW - Optical fiber sensor
KW - Humidity sensor
KW - Distributed sensor
KW - Polymer optical fiber
KW - Rayleigh scattering
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396363
UR - http://www.mdpi.com/1424-8220/17/4/738
DO - https://doi.org/10.3390/s17040738
SN - 1424-8220
VL - 17
IS - 4
SP - Article 738, 1
EP - 12
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-39636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Launert, B.
A1 - Rhode, Michael
A1 - Kromm, Arne
A1 - Pasternak, H.
A1 - Kannengießer, Thomas
ED - Olden, T.-M.
ED - Muransky, O.
ED - Edwards, L.
T1 - Residual stress influence on the flexural buckling of welded I-girders
N2 - The nonlinear analysis became a common tool to precisely assess the load-bearing behavior of steel beam and column members. The failure level is significantly influenced by different types of imperfections, among geometric also structural imperfections (residual stresses). Here are still gaps in the knowledge. Nowadays, 3-D welding simulation developed to a level where it could provide reliable estimation of weld-induced distortion and residual stresses. Nevertheless, modelling and computational effort are still in a less practicable range. In this study a simplified procedure to implement residual welding stresses in continuous large scale members is proposed and the influence on the ultimate limit state of slender members in compression is evaluated for two common structural steel grades. The results showed significant improvements in the utilization of load bearing capacity compared with simplified design methods. The comparatively general approach in this study offers
potential for future optimization.
T2 - ICRS 2016 - 10th International Conference on Residual Stresses
CY - Sydney, Australia
DA - 03.07.2016
KW - Stability Design
KW - Finit Element Method
KW - 2-D Welding Simulation
KW - Inherent Strain
KW - Plasticity-based Analysis
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389210
SN - 978-1-94529117-3
SN - 978-1-94529117-6
DO - https://doi.org/10.21741/9781945291173-19
SN - 2474-395X
VL - 2
SP - 109
EP - 114
PB - Materials Research Forum LLC
CY - Millersville (PA), USA
AN - OPUS4-38921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Cuéllar, Pablo
A1 - Benseghier, Z.
A1 - Luu, L.-H.
A1 - Bonelli, S.
A1 - Delenne, J.-Y.
A1 - Radjai, F.
A1 - Philippe, P.
T1 - Numerical insight into the micromechanics of jet erosion of a cohesive granular material
N2 - Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM) and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet.
T2 - 8th International Conference on Micromechanics on Granular Media
CY - Montpellier, France
DA - 03.07.2017
KW - Micromechanical modelling
KW - LBM-DEM
KW - Jet erosion
KW - Granular cohesion
KW - Subcritical debonding
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411186
DO - https://doi.org/10.1051/epjconf/201714015017
VL - 140
SP - Paper 15017, 1
EP - Paper 15017, 4
PB - The European Physical Journal (EPJ) - Web of Conferences
AN - OPUS4-41118
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brunier-Coulin, F.
A1 - Sarrat, J.-L.
A1 - Cuéllar, Pablo
A1 - Philippe, P.
T1 - Experimental investigation of impinging jet erosion on model cohesive granular materials
N2 - Erosion of soils affects both natural landscapes and engineering constructions as embankment dams or levees. Improving the safety of such earthen structures requires in particular finding out more about the elementary mechanisms involved in soil erosion. Towards this end, an experimental work was undertaken in three steps. First, several model materials were developed, made of grains (mostly glass beads) with solid bridges at particle contacts whose mechanical yield strength can be continuously varied. Furthermore, for most of them, we succeeded in obtaining a translucent system for the purpose of direct visualization. Second, these materials were tested against surface erosion by an impinging jet to determine a critical shear stress and a kinetic coefficient. Note that an adapted device based on optical techniques (combination of Refractive Index Matching and Planar Laser Induced Fluorescence) was used specifically for the transparent media. Third, some specifically developed mechanical tests, and particularly traction tests, were implemented to estimate the mechanical strength of the solid bridges both at micro-scale (single contact) and at macro-scale (sample) and to investigate a supposed relationship with soil resistance to erosion.
T2 - 8th International Conference on Micromechanics on Granular Media
CY - Montpellier, France
DA - 03.07.2017
KW - Erosion onset
KW - Experimental testing
KW - Cohesive granular media
KW - RIM-PLIF techniques
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411215
DO - https://doi.org/10.1051/epjconf/201714008002
VL - 140
SP - Paper 08002, 1
EP - Paper 08002, 4
PB - The European Physical Journal (EPJ) - Web of Conferences
AN - OPUS4-41121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kromm, Arne
A1 - Rhode, Michael
A1 - Launert, B.
A1 - Dixneit, Jonny
A1 - Kannengießer, Thomas
A1 - Pasternak, H.
ED - Olden, T.-M.
ED - Muransky, O.
ED - Edwards, L.
T1 - Combining sectioning method and X-ray diffraction for evaluation of residual stresses in welded high strength steel components
N2 - Residual stresses and distortions in welded I-girders for steel construction are relevant when evaluating the stability of steel beams and column members. The application of high strength steels allows smaller wall thicknesses compared to conventional steels. Therefore, the risk of buckling has to be considered carefully. Due to the lack of knowledge concerning the residual stresses present after welding in high strength steel components conservative assumptions of their level and distribution is typically applied. In this study I-girders made of steels showing strengths of 355 MPa and 690 MPa were welded with varying heat input. Due to the dimension of the I-girders and the complex geometry the accessibility for residual stress measurement using X-ray diffraction was limited. Therefore, saw cutting accompanied by strain gauge measurement has been used to produce smaller sections appropriate to apply X-ray diffraction. The stress relaxation measured by strain gauges has been added to residual stresses determined by X-ray diffraction to obtain the original stress level and distribution before sectioning. The combination of both techniques can produce robust residual stress values. From practical point of view afford for strain gauge application can be limited to a number of measuring positions solely to record the global amount of stress relaxation. X-ray diffraction can be applied after sectioning to determine the residual stresses with sufficient spatial resolution.
T2 - ICRS 2016 - 10th International Conference on Residual Stresses
CY - Sydney, Australia
DA - 03.07.2016
KW - Welding
KW - Residual Stress
KW - Sectioning Method
KW - X-Ray Diffraction
KW - Component Testing
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389206
SN - 978-1-94529117-3
SN - 978-1-94529117-6
DO - https://doi.org/10.21741/9781945291173-28
SN - 2474-395X
VL - 2
SP - 163
EP - 168
PB - Materials Research Forum LLC
CY - Millersville (PA), USA
AN - OPUS4-38920
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Niederleithinger, Ernst
A1 - Abraham, O.
A1 - Mooney, M.
T1 - Geophysical methods in civil engineering: Overview and new concepts
N2 - Geophysical methods have been used in civil engineering for decades. The main field of application is - to no surprise – in geotechnical projects from site characterization to foundation quality assurance. For more than 25 years, ground penetrating radar (GPR) and seismic methods have found applications in structural engineering. Recently introduced geophysical methods have been adopted to ultrasonic investigations in various fields. They help to improve the quality of structural imaging and to detect small changes in concrete. An overview of the history and current use of geophysics in civil engineering is given. Selected examples of new concepts include advances in wave based imaging, quality assurance for foundations, detecting small changes in concrete as well as moisture and corrosion detection are discussed.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Nondestructive testing
KW - Civil engineering
KW - Geophysics
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344666
UR - https://www.ndt.net/?id=18260
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 6
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mayer, K.
A1 - Krause, Martin
A1 - Ibrahim, M.
A1 - Schubert, Marcus
T1 - Requirements for a Small Size Ultrasonic Imaging System for Inspection of Concrete Elements
N2 - Ultrasonic imaging systems usually require an array of ultrasonic transducers for data acquisition on a wide area on top of an object under investigation. The goal of an imaging algorithm is the use of reflected ultrasound data to form a recognizable image. Conventional algorithms like SAFT are based on an inverse Huygens' principle and need therefore a dense measurement grid. This requires a big effort in data capturing. For simple and inexpensive measurement different strategies of imaging with reduced amount of data and examples with a manual scanning device on concrete elements are presented.
T2 - 19th World Conference on Non-Destructive Testing 2016
CY - Munich, Germany
DA - 13.06.2016
KW - NDT-CE
KW - Ultrasonic echo
KW - SAFT
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388548
SP - 1245
EP - 1254
PB - DGZfP
CY - Bad Breising, Germany
AN - OPUS4-38854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Philippe, P.
A1 - Cuéllar, Pablo
A1 - Brunier-Coulin, F.
A1 - Luu, L.-H.
A1 - Benahmed, N.
A1 - Bonelli, S.
A1 - Delenne, J.-Y.
T1 - Physics of soil erosion at the microscale
N2 - We focus here on the major and still relevant issue of soil erosion by fluid flows, and more specifically on the determination of both a critical threshold for erosion occurrence and a kinetics that specifies the rate of eroded matter entrainment. A state-of-the-art is first proposed with a critical view on the most commonly used methods and erosion models. It is then discussed an alternative strategy, promoting the use of model materials that allow systematic parametric investigations with the purpose of identifying more precisely the local mechanisms responsible for soil particle erosion and ultimately quantifying both critical onsets and kinetics, possibly through existing or novel empirical erosion laws. Finally, we present and discuss several examples following this methodology, implemented either by means of experiments or numerical simulations, and coupling erosion tests in several particular hydrodynamical configurations with wisely selected mechanical tests.
T2 - 8th International Conference on Micromechanics on Granular Media
CY - Montpellier, France
DA - 03.07.2017
KW - Erosion phenomena
KW - Onset of jet erosion
KW - LBM-DEM numerical simulation
KW - Experimental testing
KW - PLIF-RIM optical techniques
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411198
DO - https://doi.org/10.1051/epjconf/201714008014
VL - 140
SP - Paper 08014, 1
EP - Paper 08014, 4
PB - The European Physical Journal (EPJ) - Web of Conferences
AN - OPUS4-41119
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Daum, Werner
A1 - Hofmann, Detlef
A1 - Basedau, Frank
A1 - Brandes, K.
A1 - Kubowitz, P.
ED - Curbach, M.
ED - Opitz, H.
ED - Scheerer, S.
ED - Hampel, T.
T1 - Erweiterte Strukturabbildung von Brücken mit adaptiven mathematischen Modellen zur Lösung aktueller noch ungelöster Probleme
N2 - Health monitoring von größeren Strukturen erfordert die Betrachtung der gesamten Struktur, indem sowohl jener Bereich, der experimentell behandelt wird, als auch derjenige, der einer analytischen mechanischen Untersuchung unterzogen wird, in einem Gesamtzusammenhang erfasst wird. Die umfassende Behandlung des Problems gelingt dann in einer Gesamtmatrix, die im Beitrag vorgestellt wird. Auf eine Erweiterung der Methode zur Detektierung anwachsender Schädigungen wird hingewiesen.
KW - Structural Health Monitoring
KW - Schadensdetektion
KW - Adaptives mathematisches Modell
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:bsz:14-qucosa-201229
SN - 1613-6934
VL - Konstruktiver Ingenieurbau Dresden
IS - 43
SP - 183
EP - 188
PB - Institut für Massivbau, TU Dresden
CY - Dresden
AN - OPUS4-43371
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Erhard, Anton
A1 - Goedecke, Thomas
A1 - Menrad, Andreas
A1 - Bethke, John
T1 - Application of nondestructive testing - Methods for packaging examination
N2 - Nondestructive testing (NDT) methods are applicable in many ways for defect detection as well as optimization of packaging production processes. The visual inspection method is the technique which is mostly used, although neither the customer nor a skilled inspector may be aware of this.
Techniques like ultrasound for wall thickness measurement, the application of x-ray techniques or the use of dye penetrant techniques for crack detection are rather well known to the NDT family. However, acoustic emission techniques can also be helpful for the characterization of packaging materials. In this paper the employment of x-ray computer tomography (CT) for measurement of wall thickness in plastic jerrycans, especially on the edges, and its possible optimization of production processes will be discussed.
A comparison of the CT and ultrasonic examinations of wall thickness and the reliability of this measured data are also important points for the discussion, especially if some safety factors can be derived from the results.
The leakage test is also good for jerrycans, IBCs or other kinds of drums for the transportation and storage of dangerous goods. The disadvantage of this kind of test is that a lack of quality, e.g. wall thickness deterioration, cannot be detected if the wall thickness withstands the internal pressure. Therefore, especially for Quality assurance, the other, previously mentioned techniques are better for a statistical assessment of a batch. This paper is focused on the comparison of different NDT results with special emphasis on the large range of material mechanical properties.
T2 - 25th IAPRI Symposium on Packaging
CY - Berlin, Germany
DA - 16.05.2011
KW - Materialeigenschaft
KW - Zerstörungsfreie Prüfung
KW - Computertomographie
KW - Kunststoffbehälter
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-239191
SN - 978-3-940283-31-3
VL - 126
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-23919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Niederleithinger, Ernst
A1 - Wolf, Julia
A1 - Mielentz, Frank
A1 - Wiggenhauser, Herbert
T1 - Using embedded ultrasonic sensors for active and passive concrete monitoring
N2 - Challenging new constructions and ageing infrastructure are increasing the demand for permanent monitoring of loads and condition. Various methods and sensors are used for this purpose. But the technologies available today have difficulties in detecting slowly progressing locally confined damages. Extensive investigations or instrumentations are required so far for this purpose. In this study we present new sensors and data processing methods for ultrasonic transmission, which can be used for non-destructive long term monitoring of concrete. They can be mounted during construction or thereafter. Larger volumes can be monitored by a limited number of sensors for changes of material properties. The principles of ultrasonic transmission and influencing factors are presented. This latter include load, damages as well as environmental parameters as temperature or moisture. Various methods for data processing, e. g. coda wave interferometry are introduced. They allow the detection of very small changes in the medium. The embedded sensors are shown including mounting and operation. Application examples so far include small scale laboratory freeze-thaw experiments, localizing loads in larger concrete models, monitoring load effects on real structures as well as detecting acoustic events. Some sensors are operating already for several years. The sensors can be used as transmitter or receivers or switched between both roles. While most of the previous experiments have been active (at least one sensor serving as transmitter), new studies show that the sensors are useful as well for passive measurements, e. g. in acoustic emission or time reversal experiments. Besides application in civil engineering our setups can also be used for model studies in geosciences.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - SHM
KW - Monitoring
KW - Ultrasound concrete
KW - Embedded sensors
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344652
UR - http://www.ndt.net/?id=18408
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaenisch, Gerd-Rüdiger
A1 - Kolkoori, Sanjeevareddy
A1 - Deresch, Andreas
T1 - Influence of scattered radiation on the efficiency of dual high-energy X-Ray imaging for material characterization
N2 - In this contribution, we discuss the influence of scattered radiation on materials’ effective attenuation coefficients at higher X-ray energies. The selected X-ray spectra for the dual-energy experiments correspond to 3 MV and 7.5 MV acceleration potential of the used betatron. Experiments were performed on a test phantom containing step wedges of different low- and high-Z materials. We evaluated the ratio between low- and high-energy X-ray attenuation coefficients quantitatively based on simulated poly-energetic high-energy X-ray source spectra and the detector sensitivity using the “analytical Radiographic Testing inspection simulation tool” (aRTist) developed at BAM. Furthermore, the influence of scattered radiation is evaluated using an efficient Monte-Carlo simulation. The simulation results are compared quantitatively with experimental investigations. Finally, important applications of the proposed technique in the context of aviation security are discussed.
T2 - 19th World Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Monte Carlo methods
KW - Dual-energy imaging
KW - Simulation
KW - Experiments
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365925
SN - 978-3-940283-78-8
VL - 158
SP - 1
EP - 10
PB - DGZfP
CY - Berlin, Germany
AN - OPUS4-36592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinrich, Thomas
A1 - Traulsen, Christoph Hans-Henning
A1 - Darlatt, Erik
A1 - Richter, S.
A1 - Poppenberg, J.
A1 - Traulsen, N.L.
A1 - Linder, I.
A1 - Lippitz, Andreas
A1 - Dietrich, Paul
A1 - Dib, B.
A1 - Unger, Wolfgang
A1 - Schalley, C.A.
T1 - The versatility of 'Click' reactions at surfaces: Molecular recognition at interfaces
N2 - In order to investigate molecular recognition on surfaces, an azide-functionalized monolayer was deposited on gold. The monolayer was characterized by X-ray photoelectron spectroscopy (XPS) and angle-resolved near-edge X-ray absorption fine structure (NEXAFS) experiments and the decomposition of the azide upon irradiation with X-ray beams was investigated. Subsequently, various alkyne-functionalized host and guest molecules were attached to the azide by 1,3-dipolar cycloaddition. These modified surfaces and their host–guest chemistry were analysed by XPS and angle-resolved NEXAFS. The reversibility of guest binding was shown for one example as a proof of principle.
KW - 'Click' reaction
KW - Azide-terminated surfaces
KW - SAMs
KW - Host guest molecules
KW - Molecular recognition at interfaces
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-306463
DO - https://doi.org/10.1039/C4RA01730G
SN - 2046-2069
VL - 4
IS - 34
SP - 17694
EP - 17702
PB - RSC Publishing
CY - London
AN - OPUS4-30646
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachsmuth, Janne
T1 - Ermüdungsrisswachstum und Korrosion in Stahl P460NL1 - Vergleich von Kennwerten aus Bruchmechanik und Schallemission
N2 - Das Monitoring von Bauteilen bei Ermüdungsbelastung mit Hilfe der Schallemission liefert eine große Anzahl an Schallemissionsdaten und –parametern. Um diese in einen Zusammenhang mit dem Schadenszustand des Bauteils zu bringen ist es sinnvoll, einen Bezug zu bekannten bruchmechanischen Kenngrößen herzustellen. Dies wird in dieser Arbeit anhand von Ermüdungsversuchen an Platten aus dem Feinkornstahl P460NL1 versucht. Schallemissionssignale aus Ermüdungsrissen mit und ohne Korrosionseinfluss werden analysiert und mit bekannten bruchmechanischen Kenngrößen wie der Risswachstumsrate und dem Spannungsintensitätsfaktor verglichen.
T2 - 19. Kolloquium Schallemission - Statusberichte zur Entwicklung und Anwendung der Schallemissionsanalyse
CY - Augsburg, Germany
DA - 12.09.2013
KW - Schallemissionsprüfung
KW - Ermüdungsrisswachstum
KW - Korrosion
KW - Bruchmechanik
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-301339
UR - http://www.dgzfp.de/portals/schallemission2013/BB/vortrag%2013.pdf
SN - 978-3-940283-51-1
N1 - Serientitel: DGZfP-Berichtsband – Series title: DGZfP-Berichtsband
IS - 142
SP - 1
EP - 10 (Beitrag 13)
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung
CY - Berlin
AN - OPUS4-30133
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fiedler Bremer, C.
A1 - Scholz, R.
A1 - Myslicki, S.
A1 - Starke, P.
A1 - Boller, C.
A1 - Walther, F.
A1 - Krause, Martin
T1 - NDT-based characteriazation of timber and vulcanized fiber for civil infrastructure
N2 - The paper addresses beech wood as well as vulcanized fiber and discusses the results obtained when using acoustic emission and thermography as non-destructive testing techniques along tensile and load increase fatigue tests to characterize the wooden material’s behavior under increasing fatigue loads to get enhanced information regarding the fatigue behavior of both materials. Reference is mainly made to the materials’ anisotropic and microstructural behavior and what implications this has with respect to the materials’ strength. The influence of moisture is discussed, as well as parameters that may deserve monitoring in the sense of structural health monitoring to be applied in timber structures in general.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Ermüdung
KW - Belastungsversuch
KW - Thermographie
KW - ZfP
KW - Timber
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346377
UR - https://www.ndt.net/?id=18419
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 11
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34637
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Helmerich, Rosemarie
A1 - Mielentz, Frank
A1 - Milmann, Boris
A1 - Adam, Louisa
A1 - Villalobos, S.
A1 - Guimaraes, M.
A1 - Wiggenhauser, Herbert
T1 - Detection of cracks perpendicular to the surface using acoustic methods
N2 - Cracks perpendicular to the surface may be initial indicators for a deterioration process of concrete structures. Moisture penetrates inside the structure and transports adverse chemicals. The paper presents an investigation about the reliability of available commercial non-destructive evaluation techniques to reliably estimate the depth of surface-breaking cracks in reinforced concrete structures. Aim of the study was the investigation of surface-braking cracks under laboratory conditions. Commercial acoustic devices as impact echo equipment, single ultrasonic transducers and arrays were applied even if they have not been developed for this purpose. The commercial software and descriptions for application was followed strictly to compare the function, precision and repeatability of the measurements. Both, perpendicular notches and cracks have been considered. The study was completed with a discussion about reference specimens. The study was the basis for formulation of gaps in research. The Electric Power Research Institute (EPRI) has initiated and funded a Project.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Acoustic test
KW - Commercial acoustic devices
KW - Ultrasonic test
KW - Crack depth
KW - Concrete specimens
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345729
UR - https://www.ndt.net/?id=18412
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 9
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feldmann, Rüdiger
A1 - Zoёga, Andreas
A1 - Milmann, Boris
A1 - Krause, Martin
T1 - Ortung tiefliegender Bewehrung durch Ultraschall mit bildgebender Phasenauswertung
N2 - Die Ortung von schlaffer Bewehrung in Beton erfolgt routinemäßig mit bildgebenden Radar- oder Wirbelstromverfahren. Die Anwendung dieser Verfahren ist aber begrenzt, wenn es sich um die Ortung tiefliegender Bewehrung (ab ca. 30 cm) oder um jungen Beton handelt. Grund ist die Schwächung der Radarpulse durch oberflächennahe Bewehrung oder durch die Betonfeuchte. Das bildgebende Ultraschallechoverfahren bietet den Vorteil, dass die Ultraschallpulse in diesen Fällen eine wesentlich höhere Eindringtiefe erreichen.
Im vorliegenden Beitrag wird eine Fallstudie vorgestellt, bei der mehrlagig eingebrachte Bewehrungseisen in einer nur einseitig zugänglichen 60 cm dicken Betonplatte geortet werden sollten, um eine Kernbohrung ohne Verkanten der Bohrkrone durchzuführen.
Zur Ortung der Bewehrung wurde das Ultraschallechoverfahren mitScherwellen der Mittenfrequenz 50 kHz mit einem automatisch arbeitenden Bauwerksscanner eingesetzt. Aus den flächig aufgenommenen Messdaten wurde mit der Rekonstruktionsrechnung nach dem Prinzip der synthetischen Apertur (SAFT, Synthetic Aperture Focusing Technique) die Position der Bewehrungseisen bildhaft ortsgenau dargestellt. Dies gelingt mit einer Auswertungsoption, bei der die Phase der reflektierten Ultraschallpulse ermittelt und farbcodiert dargestellt wird (Phasenauswertung). Damit lassen sich Reflexionen der Bewehrung eindeutig von eventuellen Fehlstellen oder Rückwandechos unterscheiden.
T2 - Fachtagung Bauwerksdiagnose 2014
CY - Berlin, Germany
DA - 13.02.2014
KW - Ultraschallecho-Verfahren
KW - SAFT
KW - Bewehrung
KW - Beton
KW - Abbildungsverfahren
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351056
UR - https://www.ndt.net/?id=15885
SN - 1435-4934
VL - 19
IS - 8
SP - 1
EP - 11
PB - NDT.net
CY - Kirchwald
AN - OPUS4-35105
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Christoph
A1 - Shokouhi, P.
T1 - Data aggregation for improved honeycomb detection in concrete using machine learning-based algorithms
N2 - We present the results of several machine learning (ML)- inspired data fusion algorithms applied to multi-sensory nondestructive testing (NDT) data. Our dataset consists of Impact-Echo (IE), Ultrasonic Pulse Echo (US) and Ground Penetrating Radar (GPR) data collected on large-scale concrete specimens with built–in simulated honeycombing defects. The main objective is to improve the detectability of honeycombs by fusing the information from the three different sensors. We describe normalization, feature detection and optimal feature selection. We have used unsupervised and supervised ML, i.e., classification and clustering, for data fusion. We demonstrate the advantage of data fusion in reducing the false positives up to 10% compared to the best single sensor, thus, improving the detectability of the defects. The methods were evaluated on a concrete specimen. The effectiveness of the proposed approach was demonstrated on a separate full-scale concrete specimen. The results indicate the transportability of the conclusions from one specimen to the other.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Data fusion
KW - Concrete evaluation
KW - Honeycombing
KW - Machine learning
KW - Clustering
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-350968
UR - https://www.ndt.net/?id=18364
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-35096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rothbart, Nick
A1 - Maierhofer, Christiane
A1 - Goldammer, M.
A1 - Hohlstein, F.
A1 - Koch, J.
A1 - Kryukov, I.
A1 - Mahler, G.
A1 - Stotter, B.
A1 - Oswald-Tranta, B.
A1 - Sengebusch, M.
T1 - A round robin test of flash thermography of CFRP and metal structures
N2 - Within the scope of a DIN INS project, a flash thermography round robin test that evaluates reliability, comparability and efficiency of different testing situations is organized. The results give information about the detectability of defects e.g. by their size and depth, the evaluation method and by the materials used. Besides, the influence of equipment and parameters used by the participants on the results were analysed. All of the quantitative results as well as the feedback given by the participants will be presented in a DIN committee in order to contribute to a flash thermography standard.
T2 - 7th International Symposium on NDT in Aerospace
CY - Bremen, Germany
DA - 16.11.2015
KW - Flash thermography
KW - Round robin test
KW - Metal
KW - Flat bottom holes
KW - SNR
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351070
UR - https://www.ndt.net/?id=18921
SN - 1435-4934
VL - 21
IS - 4
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-35107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lehmann, Jens
A1 - Burkert, Andreas
T1 - KorroPad - Beurteilung der Korrosionsbeständigkeit von Oberflächen nichtrostender Stähle
N2 - Mit dem KorroPad Verfahren ist es dem Anwender möglich den Zustand der Passivschicht nichtrostender Stähle auf sehr einfache und schnelle Weise einschätzen zu können. Das Verfahren eignet sich dazu, den Grad der Passivität in Abhängigkeit der Umgebungsbedingungen und der Zeit nachzuvollziehen. Dies ermöglicht dem Anwender und Verarbeiter von nichtrostenden Stählen, die Lagerungsbedingungen und –zeiten einer frisch bearbeiteten Stahloberfläche zu ermitteln, welche für die Ausbildung einer stabilen Passivschicht notwendig sind, bevor diese risikoarm eingesetzt werden kann. Wie die hier dargestellten Beispiele und auch weitere zahlreiche praktische Anwendungen gezeigt haben, eignet sich das KorroPad ebenfalls für die Identifikation kritischer Prozessparameter bei der Verarbeitung nichtrostender Stähle. Mit dem Verfahren lassen sich viele prozessbedingte Einflussfaktoren auf die Oberflächengüte wie auch auf den Werkstoff charakterisieren. Aufgrund der schnellen und einfachen Auswertung der Prüfergebnisse können positive wie auch negative Veränderungen hinsichtlich der Passivschichtstabilität zügig erkannt werden. Dies ermöglicht es dem Anwender schnell zu reagieren, um kritische Einflüsse zu korrigieren und um eine Optimierung von Inhouse-Prozessen durchzuführen. Weitere Einsatzgebiete sind im Bereich der Wareneingangs- und/oder Warenausgangskontrolle denkbar, überall wo es um die Frage der Passivschichtstabilität einer nichtrostenden Stahloberfläche geht.
T2 - Fachtagung Bauwerksdiagnose - Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben
CY - Berlin, Germany
DA - 25.02.2016
KW - Korrosionsschnelltest, Nichtrostender Stahl, Passivschicht, KorroPad
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355146
SN - 978-3-940283-77-1
VL - 157
SP - 1
EP - 7
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-35514
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schlick-Hasper, Eva
A1 - Schneider, Uwe
A1 - Goedecke, Thomas
A1 - Kraume, M.
T1 - Durchströmung von Glaskapillaren mit Lachgas und Helium
N2 - Distickstoffmonoxid (N2O, Lachgas) und Helium (He) sind gängige Prüfgase für Dichtheitsprüfungen. Die einfachste Leckgeometrie stellt ein ideal zylindrisches Rohr dar. Es wurden Glaskapillaren verschiedener Abmessungen mit Lachgas und Helium durchströmt. Der Überdruck am Kapillareingang lag zwischen 100 mbar und 400 mbar. Es handelte sich um vier annähernd zylindrische Glaskapillaren mit den mittleren Durchmessern: Kapillare 1: ca. 102 μm; Kapillare 2: ca. 71 μm; Kapillare 3B: ca. 49 μm; Kapillare 4: ca. 53 μm. Zudem wurde eine nichtzylindrische Kapillare geprüft (Kapillare 3A). Die Kapillaren 1, 2 und 3B wurden mit beiden Prüfgasen getestet. Kapillare 3A wurde nur mit Lachgas durchströmt, Kapillare 4 nur mit Helium. Für die Messung der Leckageraten kam das Überdruckverfahren mit Ansammlung (Verfahren B3 nach DIN EN 1779: 1999-10) zum Einsatz. Als Detektor für Lachgas diente der Lachgasdetektor Maihak Unor 6 N, für Helium der Leckdetektor T-Guard der Firma Inficon.
Es wurden verschiedene Theorieansätze verglichen. Beim Theorieansatz Ib erfolgte die Umrechnung der Lachgas-Messwerte auf die Helium-Messwerte und umgekehrt anhand der Druck-, Temperatur- und Gasartabhängigkeit der Leckagerate für laminar-viskose Gasströmung (DIN EN 1779: 1999-10; DGZfP-Richtlinie DP2: 2009-12). Beim Theorieansatz II wurde die Berechnung der Leckagerate für die laminar-viskose Rohrströmung unter der Annahme einer ideal zylindrischen Kapillare durchgeführt. Zusätzlich wurde mit „ANSYS Fluent“ eine CFD-Simulation vorgenommen. Bei Kapillare 3A wurde eine Serienschaltung der Strömungsleitwerte von Rohr und Düse angesetzt. Bei Anwendung des Ansatzes Ib werden bei Umrechnung der Helium-Messwerte auf Lachgas die Lachgas-Messwerte überschätzt. Umgekehrt werden bei der Umrechnung der Lachgas-Messwerte auf Helium die Helium-Messwerte unterschätzt. Bei Analyse der Einlauflängen der Rohrdurchströmung ist festzustellen, dass diese für Lachgas stets größer als für Helium sind. Bei Lachgas liegt daher für einige Messwerte noch keine ausgebildete laminare Rohrströmung vor. Einlaufeffekte können somit nicht vernachlässigt werden. Als Fazit ergibt sich, dass bei Verwendung von Helium als Prüfgas und Umrechnung der Helium-Messwerte auf Lachgas die Lachgas-Leckageraten sicherheitstechnisch konservativ abgeschätzt werden.
T2 - 7. DGZfP-Fachseminar Dichtheitsprüfung und Lecksuche
CY - Dortmund, Germany
DA - 20.09.2016
KW - Laminare Strömung
KW - Glaskapillaren
KW - Lachgas
KW - Helium
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-380965
UR - http://www.dgzfp.de/seminar/lecksuche/Pr%C3%A4sentationen
SP - 1
EP - 15
AN - OPUS4-38096
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Millar, Steven
A1 - Gottlieb, Cassian
A1 - Wilsch, Gerd
A1 - Eichler, Thorsten
A1 - Bohling, C.
A1 - Molkenthin, A.
T1 - Laser induced breakdown spectroscopy (LIBS) - On-site investigatioons on a bridge with a mobile LIBS-system
N2 - LIBS is on the step from a laboratory application to on-site analysis. A validated mobile LIBS-system for on-site application on building materials is under development at BAM in cooperation with industrial partners (system developers and companies), who will use this technique for investigation on building structures like bridges and parking decks. The system is designed to measure the content of harmful species like chlorine, sulfur or alkalis, to give the engineer a tool for the estimation of the condition of concrete structures and for quality assurance during concrete repair work on-site. In these work results of on-site measurements on a chloride contaminated bridge are shown. Further work will focus on providing guidelines to establish LIBS as a standard procedure for chemical investigations of building materials.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - LIBS
KW - Chlorides
KW - Sulfur
KW - Alkalis
KW - Corrosion
KW - ASR
KW - Chemical analysis
KW - Chloride
KW - Elementanalyse
KW - Natrium
KW - Baustoffuntersuchungen
KW - Baustoffe
KW - Dauerhaftigkeit
KW - Messsysteme
KW - Mobiles LIBS
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345795
UR - http://www.ndt.net/?id=18296
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 5
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34579
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grothe, Sven
T1 - Ultrasonic signal evaluation used to detect weather-related temperature changes in a concrete specimen
N2 - Ultrasonic measurement evaluation methods have been proven to be effective for detection of subtle changes, caused by temperature, load or moisture. However, for its application outdoors it is necessary to analyse unavoidable influences, such as weather. Therefore an ultrasonic monitoring system with 40 ultrasonic sensors (20 transmitters, 20 receivers; 25 kHz central frequenzy) has been implemented on a concrete specimen (4×5×0.8m3), that is exposed to weather conditions. Data from 400 sensor combinations was collected over a period of six months with an interval of two hours. The data was evaluated by both qualitative (correlation techniques) and quantitative (ultrasonic velocity changes via Coda Wave Interferometry and time of flight method) evaluation methods and compared to the temperature changes caused by weather.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346398
UR - https://www.ndt.net/?id=18336
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
A1 - Chien, M.
A1 - Bavendiek, F.
A1 - Krankenhagen, Rainer
T1 - Thermografische Schichtdickenbestimmung von Oberflächenschutzsystemen für Beton
N2 - Im Bauwesen werden Polymerbeschichtungen auf Beton häufig eingesetzt um zum einen ein bestimmtes Aussehen zu schaffen und zum anderen das Bauteil vor Alterung, Verschleiß und Schädigung zu schützen. Für praktisch alle Ziele ist die Wirkung von der eigens dafür definierten Schichtdicke der Polymerbeschichtung abhängig. Daher wird die Dicke der Beschichtung nach erfolgtem Schichtauftrag überprüft. Für den in diesem Zusammenhang anspruchsvollen mineralischen Untergrund Beton stehen bislang allerdings nur zerstörende Prüfverfahren zur Verfügung. Aus diesem Grund wurden im Rahmen des Projektes IRKUTSK ein auf aktiver Thermografie basierendes Verfahren sowie ein Gerät für den vor-Ort-Einsatz entwickelt, mit dessen Hilfe eine zerstörungsfreie Schichtdickenbestimmung möglich ist.
Hier wird ein kurzer Einblick in das zur Schichtdickenbestimmung entwickelte Thermografieverfahren gegeben. Die Besonderheiten bei der quantitativen Auswertung, die durch die Teiltransparenz der Polymerbeschichtungen auftreten, werden erläutert. Die Funktion des Verfahrens für einlagige Systeme wird anhand von La-bormessungen illustriert.
T2 - Thermographie-Kolloquium 2017
CY - Berlin, Germany
DA - 28.09.2017
KW - Schichtdickenbestimmung
KW - Beton
KW - Oberflächenschutzsystem
KW - Thermografie
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-423577
SN - 978-3-940283-88-7
VL - 163
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-42357
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pasternak, H.
A1 - Launert, B.
A1 - Kannengießer, Thomas
A1 - Rhode, Michael
T1 - Advanced residual stress assessment of plate girders through welding simulation
N2 - This article provides an impression on potentials in applying nowadays welding simulation tools in construction design. This is carried out exemplary on plate girders from two structural steel grades. The calculated residual stresses are compared with measurements by sectioning method. It has been repeatedly stated that present Eurocode models fail to approximate the residual stresses. Especially for high strength steel (HSS) only limited information is available on realistic occurring residual stresses in typical I-girders. The investigations are aimed to give further guidance on these values. A few proposals on advanced models are discussed.
T2 - MBST 2016 - Modern Building Materials, Structures and Techniques
CY - Vilnius, Litunia
DA - 26.05.2016
KW - Residual stresses
KW - Plate girders
KW - I-shape sections
KW - High-strength steel
KW - Welding simulation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-392177
UR - http://www.sciencedirect.com/science/article/pii/S1877705817305192
DO - https://doi.org/10.1016/j.proeng.2017.02.013
SN - 1877-7058
IS - 172
SP - 23
EP - 30
PB - Elsevier
CY - Amsterdam, Niederlande
AN - OPUS4-39217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Galindo Guerreros, Julio Cesar
A1 - Niederleithinger, Ernst
A1 - Mackens, S.
A1 - Fechner, T.
T1 - Quality assurance of jet grout columns with borehole seismic measurements
N2 - Sealing and strengthening of the subsoil by injection is a major issue in the field of geotechnical engineering. One commonly applied method is jet grouting, which allows creating columns of grouted soil by eroding and mixing the in-situ soil with a thin cement suspension. A general difficulty linked with this method is to predict the resulting column diameter and its material strength. In this paper we illustrate the application of a newly developed non-destructive quality assurance testing tool used to determine the diameter of jet grout columns. This approach incorporates standard crosshole and downhole seismic measurements. To demonstrate its effectiveness, we tested the new approach within two-dimensional finite-difference numerical simulations. Additional field tests showed that this tool is also applicable in real site conditions. For this purpose, three jet grout columns were produced with different process parameters in a depth between 3.0 and 10 m. The evaluated diameters were within 1.0 and 1.5 m, slightly deviating from the previously predicted range by the jet grouting contractor. Moreover, we were able to detect the base of the columns at 10 m depth with no significant difficulties. On the other hand, unsaturated, partly unconsolidated sands between ground water level and surface considerably affected the seismic data, hence complicating the detection of the top of the columns.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Jet grout
KW - Seismics
KW - Crosshole
KW - Downhole
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346753
UR - https://www.ndt.net/?id=18277
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 7
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dey, Anika
A1 - Casperson, Ralf
A1 - Pohl, Rainer
A1 - Thomas, Hans-Martin
A1 - Heyder, R.
T1 - Erfahrungen mit der Wirbelstromprüfung beim Einsatz an unterschiedlichen Schienenstahlsorten
N2 - Die steigenden Anforderungen im Schienenverkehr haben u. a. wachsende Betriebsbeanspruchungen für das Führungselement Schiene zur Folge. Auf Strecken mit hohen Belastungen wird dadurch die Entstehung von Rollkontaktermüdungsrissen, den sog. Head Checks, begünstigt. Für die Quantifizierung von Schäden im Hinblick auf eine optimierte Instandhaltung, setzt die DB AG daher seit einigen Jahren die Wirbelstromprüfung an Schienen ein. Es wurde ein Wirbelstromprüfsystem speziell für die Detektion und Bewertung von Head Checks auf der Schienenstahlsorte R260 entwickelt. Um den Instandhaltungsaufwand möglichst gering zu halten, unterliegen Eisenbahnschienen einer ständigen technologischen Weiterentwicklung durch die Hersteller. Durch Verbesserung der Schienenstahlsorten soll ein größerer Widerstand gegen die Bildung von Rollkontaktermüdungsrissen erreicht werden. Anhand von Streckenversuchen der DB AG in den letzten Jahren konnte festgestellt werden, dass tatsächlich eine Verminderung der Risswachstumsgeschwindigkeit erzielt wurde. Dafür zeigten sich im Vergleich zur Stahlsorte R260 abweichende Rissgeometrien, geringere Abstände zwischen den Ermüdungsrissen und somit eine größere Dichte des Rissfeldes. Die daraus resultierenden Folgen für die Ergebnisse der Wirbelstromprüfung werden hier erläutert. Praktische Prüferfahrungen an Schienenstahlsorten mit höherer Festigkeit werden vorgestellt.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Wirbelstromprüfung
KW - Rollkontaktermüdung
KW - Schienenstahlsorten
KW - Schienenfehler
KW - Eisenbahnschiene
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-252793
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.2.A.4)
SP - 1
EP - 10
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25279
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Osterloh, Kurt
A1 - Fratzscher, Daniel
A1 - Zscherpel, Uwe
A1 - Ewert, Uwe
A1 - Hasenstab, A.
A1 - Bücherl, T.
A1 - Schillinger, B.
T1 - Partielle Tomographie mit Neutronen zur Beurteilung von Leimschichten in Holz
N2 - Verleimte Holzproben wurden je nach Größe mit thermischen (ANTARES) bzw. schnellen Neutronen (NECTAR) an der Forschungs-Neutronenquelle Heinz Maier-Leibnitz (FRM II) der Technischen Universität München in Garching untersucht. Entweder ließen die durchstrahlbare Schichtdicke oder die eingeschränkte Strahlgeometrie es nicht zu, das Probenteil allseitig zu durchstrahlen.
Um dennoch innere Strukturen wie Leimschichten zumindest mit einem eingeschränkten Winkelbereich tomographisch darzustellen, wurde mit Hilfe des Slice-Theorems erfolgreich rekonstruiert. Ein Brett von 2 cm Dicke wurde mit thermischen Neutronen erfolgreich untersucht, ein größeres mit schnellen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Neutronentomographie
KW - Eingeschränkter Winkelbereich
KW - Holz
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250649
SN - 978-3-940283-33-7
VL - 127
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-25064
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Osterloh, Kurt
A1 - Ewert, Uwe
A1 - Zvizdic, D.
A1 - Krstelj, V.
T1 - Die EFNDT Arbeitsgruppe 5 'Öffentliche Sicherheit mit ZfP-Techniken' neu formiert
N2 - Für die öffentliche Sicherheit wird gesorgt, indem Gefahren rechtzeitig entdeckt werden. Deren Ursprung kann im technischen oder menschlichen Versagen liegen, womit im englischen Sprachraum zwischen 'Safety' und 'Security' unterschieden wird. Hinsichtlich der Folgen verschwimmt aber dieser Unterschied, obwohl für deren Verhinderung unterschiedliche Zuständigkeiten existieren. Bezüglich des gemeinsamen Interesses und auch überlappender Methoden und Vorgehensweisen würden beide Seiten gewinnen können, wenn es eine Brücke zwischen ihnen gäbe. Eine solche zu schaffen hat sich die EFNDT Arbeitsgruppe (Working Group) 5 zur Aufgabe gestellt. Gestaltet werden soll sie durch gemeinsame Veranstaltungen und Seminaren, die zur Bildung von Konsortien und der Durchführung gemeinsamer Projekte führen sollen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 03.05.2011
KW - EFNDT Working Group 5
KW - Technische und öffentliche Sicherheit
KW - Gemeinsamkeiten in ZfP und öffentlicher Sicherheit
KW - Brückenbildung zwischen Zuständigkeitsbereichen
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250631
SN - 978-3-940283-33-7
VL - 127
SP - 1
EP - 5
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-25063
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Eckey, Andreas
A1 - Pohl, Rainer
A1 - Allner, C.
A1 - Beilken, D.
T1 - Wirbelstromprüfsystem für Schienenbearbeitungsmaschinen
N2 - PLR Prüftechnik Linke & Rühe Magdeburg und die BAM Bundesanstalt für Materialforschung und -prüfung Berlin haben in Zusammenarbeit mit anderen Partnern im Laufe der letzten Jahre verschiedene Wirbelstromsysteme zur Prüfung verlegter Schienen auf rissartige Fehler des Typs Head Checks entwickelt. Die Entwicklung dieser Systeme erfolgte mit dem Ziel, ein Hilfsmittel für die Planung von Schieneninstandhaltungsmaßnahmen zu schaffen. Die Systeme haben sich im praktischen Prüfeinsatz bewährt. Hierzu wurde regelmäßig auf den vorhergehenden Tagungen berichtet. Bei der Schieneninstandhaltung kommen unterschiedliche Typen von Schienenbearbeitungsmaschinen zum Einsatz, z. B. Schienenfräs- und Schleifzüge. Seit einiger Zeit wird von Seiten der Schienennetzbetreiber vermehrt ein Qualitätsnachweis nach erfolgter Schienenbearbeitung gefordert. Hierzu wurde ein Wirbelstromprüfsystem entwickelt, dass speziell an die Erfordernisse der Qualitätsüberwachung in Schienenbearbeitungsmaschinen angepasst ist. Das Prüfsystem wird vorgestellt und über erste Erfahrungen aus dem praktischen Einsatz wird berichtet.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Wirbelstromprüfung
KW - Schienenbearbeitung
KW - ZfP
KW - Eisenbahn
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-290651
SN - 978-3-940283-49-8
IS - Poster 62
SP - 1
EP - 6
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-29065
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gradt, Thomas
A1 - Schneider, Thomas
T1 - Tribological performance of MoS2 coatings in various environments
N2 - Molybdenum disulfide (MoS₂) is a well-known solid lubricant for tribosystems running in vacuum or dry gases. Problems arise due to its sensitivity to humidity, which is a drawback for its application under ambient conditions. However, by using a physical vapor deposition (PVD) process, deposition parameters can be optimized not only to gain a coatings structure with favorable frictional properties but also to minimize the sensitivity to attack by water molecules. Therefore, an improved tribological behavior even under moist conditions can be achieved. MoS₂coatings are also candidates for being applied at cryogenic temperatures. They already have proven their suitability, e.g., for sliding support elements between superconducting magnets of the nuclear fusion-experiment Wendelstein 7-X. However, these coatings were exclusively produced for this particular application and the utilization for more common tribosystems may be precluded due to cost considerations. In view of a wider range of applications, pure and Cr containing PVD-MoS₂ coatings with an optimized structure were tested under varying environments including hydrogen gas and cryogenic temperatures. Results of the most promising variant are presented in this paper.
KW - Solid lubrication
KW - MoS2
KW - Extreme environments
KW - Hydrogen
KW - Cryogenic einvironment
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-381460
DO - https://doi.org/10.3390/lubricants4030032
SN - 2075-4442
VL - 32
IS - 4
PB - MPPI AG
CY - Basel, Switzerland
AN - OPUS4-38146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kanje, S.
A1 - Hober, S.
A1 - Mueller, L.
A1 - Herrmann, Antje Jutta
T1 - Next generation of labeling reagents for quantitative and multiplexing immunoassays by the use of LA-ICP-MS
N2 - Immuno imaging by the use of Laser Ablation Inductively Coupled Mass Spectrometry (LA-ICP-MS) is a growing research field in life sciences such as biology and biomedicine. Various element labeling strategies for antibodies have been developed for the application of multiplex immunoassays analyzed by the use of LA-ICP-MS. High multiplexing capabilities, a wide linear dynamic range and the possibility of absolute quantification are the main advantages of ICP-MS. But in the context of immuno imaging by the use of LA-ICP-MS, quantification of analytes is limited due to non-controllable antibody labeling chemistry. In the presented proof-of-principle a novel antibody labeling technique has been investigated which results in a controlled labeling degree. A small affinity protein based on the C2 domain of protein G was modified with conventional metal coded tags (MeCAT) after introducing a cysteine into the C-terminus of the protein. The modified C2 domain photo-crosslinks to the Fc or Fab region of the IgG and allows specific and covalent labeling of antibodies for multiplex immunoassay analysis by the use of LA-ICP-MS. In combination with a house-made calibration membrane the amount of labeled antibody–antigen complexes in a multiplex western blot immunoassay was determined by LA-ICP-MS.
KW - LA-ICP-MS based immunoassays
KW - Antibody labeling
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-384712
DO - https://doi.org/10.1039/c6an01878e
SN - 0003-2654
SN - 1364-5528
VL - 141
IS - 23
SP - 6374
EP - 6380
PB - The Royal Society of Chemistry
AN - OPUS4-38471
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, F.
A1 - Heinrich, Thomas
A1 - Lippitz, Andreas
A1 - Unger, Wolfgang
A1 - Schalley, C.
T1 - A photoswitchable rotaxane operating in monolayers on solid support
N2 - A novel photoswitchable rotaxane was synthesised and its switching behaviour in solution was analysed with NMR and UV-Vis. A monolayer of rotaxanes was deposited on glass surfaces and the on-surface photoswitching was investigated. Angle-resolved NEXAFS spectra revealed a preferential orientation that reversibly changes upon switching.
KW - XPS
KW - NEXAFS
KW - Photoswitchable rotaxane
KW - Self assembly
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-386814
DO - https://doi.org/10.1039/c6cc08586e
SN - 0022-4936
SN - 1364-548X
SN - 0009-241x
SN - 1359-7345
VL - 52
IS - 100
SP - 14458
EP - 14461
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-38681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Orts Gil, Guillermo
A1 - Natte, Kishore
A1 - Österle, Werner
T1 - Multi-parametric reference nanomaterials for toxicology: state of the art, future challenges and potential candidates
N2 - A major requirement for the validation of methods assessing the risk associated with engineered nanoparticles (ENPs) is the use of reference materials (RMs). In the present contribution we review available RMs, ongoing projects and characterisation trends in the field. The conclusion is that actual approaches to RMs mostly deal with metrological considerations about single properties of the ENPs, typically their primary size, which can hardly be representative of nanoparticles characteristics in real testing media and therefore, not valid for reliable and comparable toxicological studies. As an alternative, we discussed the convenience and feasibility of establishing multi-parametric RMs for a series of ENPs, focusing on silica nanoparticles (SNPs). As a future perspective, the need to develop RMs based on hybrid nanoparticles is also discussed.
KW - Referenzmaterialien
KW - Nanopartikel
KW - Toxikologie
KW - Metrologie
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-292997
DO - https://doi.org/10.1039/c3ra42112k
SN - 2046-2069
VL - 3
IS - 40
SP - 18202
EP - 18215
PB - RSC Publishing
CY - London
AN - OPUS4-29299
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kasper, J.
A1 - Hermanns, M.
A1 - Bantz, C.
A1 - Maskos, Michael
A1 - Stauber, R.
A1 - Pohl, C.
A1 - Unger, R. E.
A1 - Kirkpatrick, J.C.
T1 - Inflammatory and cytotoxic responses of an alveolar-capillary coculture model to silica nanoparticles: comparison with conventional monocultures
N2 - To date silica nanoparticles (SNPs) play an important role in modern technology and nanomedicine. SNPs are present in various materials (tyres, electrical and thermal insulation material, photovoltaic facilities). They are also used in products that are directly exposed to humans such as cosmetics or toothpaste. For that reason it is of great concern to evaluate the possible hazards of these engineered particles for human health. Attention should primarily be focussed on SNP effects on biological barriers. Accidentally released SNP could, for example, encounter the alveolar-capillary barrier by inhalation. In this study we examined the inflammatory and cytotoxic responses of monodisperse amorphous silica nanoparticles (aSNPs) of 30 nm in size on an in vitro coculture model mimicking the alveolar-capillary barrier and compared these to conventional monocultures.
Methods
Thus, the epithelial cell line, H441, and the endothelial cell line, ISO-HAS-1, were used in monoculture and in coculture on opposite sides of a filter membrane. Cytotoxicity was evaluated by the MTS assay, detection of membrane integrity (LDH release), and TER (Transepithelial Electrical Resistance) measurement. Additionally, parameters of inflammation (sICAM-1, IL-6 and IL-8 release) and apoptosis markers were investigated.
Results
Regarding toxic effects (viability, membrane integrity, TER) the coculture model was less sensitive to apical aSNP exposure than the conventional monocultures of the appropriate cells. On the other hand, the in vitro coculture model responded with the release of inflammatory markers in a much more sensitive fashion than the conventional monoculture. At concentrations that were 10-100fold less than the toxic concentrations the apically exposed coculture showed a release of IL-6 and IL-8 to the basolateral side. This may mimic the early inflammatory events that take place in the pulmonary alveoli after aSNP inhalation. Furthermore, a number of apoptosis markers belonging to the intrinsic pathway were upregulated in the coculture following aSNP treatment. Analysis of the individual markers indicated that the cells suffered from DNA damage, hypoxia and ER-stress.
Conclusion
We present evidence that our in vitro coculture model of the alveolar-capillary barrier is clearly advantageous compared to conventional monocultures in evaluating the extent of damage caused by hazardous material encountering the principle biological barrier in the lower respiratory tract.
KW - Silica nanoparticles
KW - Alveolar-capillary coculture model
KW - Cytotoxicity
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-254217
DO - https://doi.org/10.1186/1743-8977-8-6
SN - 1743-8977
VL - 8
IS - 6
SP - 1
EP - 16(?)
PB - BioMed Central
CY - London
AN - OPUS4-25421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hanelt, Sven
A1 - Friedrich, Jörg Florian
A1 - Meyer-Plath, Asmus
T1 - UV spectrometric indirect analysis of brominated MWCNTs with UV active thiols and an alkene-reaction kinetics, quantification and differentiation of adsorbed bromine and oxygen
N2 - Indirect UV-absorption spectrometry was shown to be a valuable tool for chemical characterization of functionalized carbon nanotubes (CNTs). It complements data from X-ray photoelectron spectroscopy (XPS) or FTIR analysis since it helps to clarify the type and concentration of functional groups. The principles of indirect application of UV-spectrometry and its mathematical interpretation are discussed. Their facile application, together with their adequate sensitivity and high flexibility, make UV-absorption-based approaches a valuable alternative to fluorescence spectrometry. Here, the approach was applied to the chemical analysis of oxidizing substances on CNTs. For this, pristine CNTs of low but finite oxygen content as well as brominated CNTs were analyzed by reaction in suspension with UV-active thiol reagents and a styrene derivative. It was shown that carefully selected reagents allow differentiation and quantification of bromine and generally oxidizing entities like oxygen. For brominated CNTs, it was shown that physisorbed bromine may dominate the overall bromine content.
KW - Carbon nanotubes
KW - CNTs
KW - UV-spectrometry
KW - Bromination
KW - Thiols
KW - Mercaptans
KW - Disulfides
KW - Quantification
KW - Kinetics
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-289077
DO - https://doi.org/10.3390/ma6083035
SN - 1996-1944
VL - 6
IS - 8
SP - 3035
EP - 3063
PB - MDPI
CY - Basel
AN - OPUS4-28907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stajanca, Pavol
A1 - Krebber, Katerina
T1 - Radiation-induced attenuation of perfluorinated polymer optical fibers for radiation monitoring
N2 - Due to some of their unique properties, optical fiber dosimeters are attractive and extensively researched devices in several radiation-related areas. This work evaluates the Performance and potential of commercial perfluorinated polymer optical fibers (PF-POFs) for radiation Monitoring applications. Gamma radiation-induced attenuation (RIA) of two commercial PF-POFs is evaluated in the VIS spectral region. Influence of a dose rate and temperature on RIA measurement is investigated, along with defect stability and measurement repeatability. Co-extruded PF-POFs are identified as more suitable for radiation monitoring applications due to lower dose-rate dependence.
With co-extruded PF-POF, RIA measurement holds potential for highly-sensitive radiation Monitoring with good reproducibility. The results show that operation in the blue part of the spectrum provides most favorable performance in terms of the largest nominal Radiation sensitivity, lower temperature, and dose-rate dependence as well as higher defect stability. We demonstrate for the first time to our knowledge, that PF-POFs can be used for distributed detection of radiation with doses down to tens of Grays. The off-the-shelf, user-friendly PF-POF could be of interest as a cheap, disposable sensor for various applications, especially of a more qualitative nature.
KW - Perfluorinated polymer optical fiber
KW - Cytop
KW - Ionizing radiation
KW - Radiation-induced attenuation
KW - Gamma radiation monitoring
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419504
DO - https://doi.org/10.3390/s17091959
SN - 1424-8220
VL - 17
IS - 9
SP - Article 1959, 1
EP - 12
PB - MDPI
AN - OPUS4-41950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pelkner, Matthias
A1 - Neubauer, Andreas
A1 - Reimund, Verena
A1 - Kreutzbruck, Marc
T1 - Routes for GMR-sensor design in non-destructive testing
N2 - GMR sensors are widely used in many industrial segments such as information technology, automotive, automation and production, and safety applications. Each area requires an adaption of the sensor arrangement in terms of size adaption and alignment with respect to the field source involved. This paper deals with an analysis of geometric sensor parameters and the arrangement of GMR sensors providing a design roadmap for non-destructive testing (NDT) applications. For this purpose we use an analytical model simulating the magnetic flux leakage (MFL) distribution of surface breaking defects and investigate the flux leakage signal as a function of various sensor parameters. Our calculations show both the influence of sensor length and height and that when detecting the magnetic flux leakage of µm sized defects a gradiometer base line of 250 µm leads to a signal strength loss of less than 10% in comparison with a magnetometer response. To validate the simulation results we finally performed measurements with a GMR magnetometer sensor on a test plate with artificial µm-range cracks. The differences between simulation and measurement are below 6%. We report on the routes for a GMR gradiometer design as a basis for the fabrication of NDT-adapted sensor arrays. The results are also helpful for the use of GMR in other application when it comes to measure positions, lengths, angles or electrical currents.
KW - Giant magneto resistance
KW - Non-destructive testing
KW - Magnetic flux leakage
KW - Sensor array
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-271325
DO - https://doi.org/10.3390/s120912169
SN - 1424-8220
VL - 12
IS - 9
SP - 12169
EP - 12183
PB - MDPI
CY - Basel
AN - OPUS4-27132
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gaebler, A.
A1 - Moessinger, A.
A1 - Goelden, F.
A1 - Manabe, A.
A1 - Goebel, M.
A1 - Follmann, R.
A1 - Koether, D.
A1 - Modes, C.
A1 - Kipka, A.
A1 - Deckelmann, M.
A1 - Rabe, Torsten
A1 - Schulz, Bärbel
A1 - Kuchenbecker, Petra
A1 - Lapanik, A.
A1 - Mueller, S.
A1 - Haase, W.
A1 - Jakoby, R.
T1 - Liquid crystal-reconfigurable antenna concepts for space applications at microwave and millimeter waves
N2 - Novel approaches of tunable devices for millimeter wave applications based on liquid crystal (LC) are presented. In the first part of the paper, a novel concept of a tunable LC phase shifter realized in Low Temperature Cofired Ceramics technology is shown while the second part of the paper deals with a tunable high-gain antenna based on an LC tunable reflectarray. The reflectarray features continuously beam scanning in between ±25°. Also first investigations on radiation hardness of LCs are carried out, indicating that LCs might be suitable for space applications.
KW - Tunable antenna
KW - Phase shifter
KW - Liquid crystal
KW - LTCC
PY - 2009
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-194273
DO - https://doi.org/10.1155/2009/876989
SN - 1687-5877
VL - 2009
IS - Article ID 876989
SP - 1
EP - 7
PB - Hindawi Publishing Corporation
CY - New York, NY, USA
AN - OPUS4-19427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Risse, Kerstin
A1 - Nikiforidis, Constantinos V.
A1 - Morris, Imogen
A1 - Thünemann, Andreas
A1 - Drusch, Stephan
T1 - Regulating the heat stability of protein-phospholipid stabilised oil-water emulsions by changing the phospholipid headgroup or fatty acyl chain
N2 - Stabilising oil–water emulsions remains a central challenge across food, pharmaceutical and cosmetic applications. β-lactoglobulin (β-LG) and phospholipids (PLs) can act synergistically at oil-water interfaces: PLs adsorb rapidly, while β-LG forms a viscoelastic protein network that enhances long-term stability. However, competitive adsorption between proteins and PLs can disrupt interfacial structure. In addition, for commercial production, emulsions are often exposed to heat treatment during or after manufacture, for instance due to food safety requirements. Yet, the combined effects of PL structure and heat treatment on interfacial organisation and emulsion stability remain poorly understood.
Here we show that PL saturation and processing temperature jointly determine interfacial organisation, protein-PL interactions and emulsion stability. Using β-LG-PL emulsions, we combined ζ-potential measurements, small-angle X-ray scattering (SAXS), micro-differential scanning calorimetry (μDSC), X-ray diffraction and confocal laser scanning microscopy (CLSM) to link interfacial composition with functional stability.
Below the β-LG denaturation temperature (≤75 °C), saturated PLs promoted partial unfolding of β-LG at the interface without displacement, producing mixed protein-PL networks with enhanced viscoelasticity and stability. Unsaturated PLs displaced β-LG, yielding less elastic interfaces and promoting protein aggregation in the bulk. At ≥75 °C, increased hydrophobicity intensified protein-protein interactions irrespective of PL type.
Our findings reveal that saturated PLs shift the β-LG denaturation temperature upward by restricting molecular mobility, without preventing quaternary-level protein-protein interactions. Thermal denaturation, regardless of PL type, promoted interfacial multilayer formation at 90 °C. These results provide a mechanistic framework for tailoring emulsion stability via lipid saturation and processing temperature.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Reference Method
KW - Colloid
KW - Nanoparticle
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648956
DO - https://doi.org/10.1016/j.jcis.2025.139530
SN - 0021-9797
VL - 705
SP - 1
EP - 25
PB - Elsevier Inc.
AN - OPUS4-64895
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiehle, Philipp
A1 - Härder, Michelle
A1 - Strangfeld, Christoph
T1 - Quantification of moisture content in earth block masonry under natural climatic conditions
N2 - The aim of this study is to accurately predict the moisture content in earth block masonry exposed to natural climatic conditions, which is a key factor in assessing its load-bearing capacity. Nuclear magnetic resonance relaxometry and humidity sensor measurements were carried out to quantify the moisture content. In addition, a customised test setup was developed to determine the capillary water absorption of earth blocks. This approach takes into account the deceleration of water absorption due to the swelling of clay minerals and organic additives, which leads to realistic transport coefficients in the hygroscopic range. This allows the moisture content of earth block masonry to be predicted accurately. With regard to the moisture behaviour of typical exterior wall constructions in living spaces, it was found that the equilibrium moisture content in earth block masonry is always lower than 65 % relative humidity, which corresponds to the permissible limit of the recently published German design standard for load-bearing earth block masonry.
KW - Earth block masonry
KW - NMR relaxometry
KW - Hygrothermal simulation
KW - Load-bearing capacity
KW - Moisture content
KW - Embedded humidity sensors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623518
DO - https://doi.org/10.1016/j.conbuildmat.2024.139513
VL - 459
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-62351
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayat, Mehmet Emin
A1 - Kipphardt, Heinrich
A1 - Tiebe, Carlo
A1 - Tuma, Dirk
A1 - Engelhard, Carsten
T1 - Trace-Level Ammonia–Water Interactions in Hydrogen: Challenges in Gas Purity Analysis Using Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS)
N2 - Ammonia is a critical impurity in hydrogen fuel due to its irreversible poisoning effect on proton exchange membrane fuel cells. Therefore, international standards (e.g., ISO 14687) set a stringent threshold of 100 nmol/mol. Furthermore, with the growing potential use of ammonia as a hydrogen carrier, its accurate quantification is becoming increasingly important. However, the presence of trace humidity poses analytical challenges, as ammonia may interact with water or interfaces, thereby affecting its detectability. Therefore, the goal of this work is to enable accurate trace ammonia quantification for hydrogen purity measurements through fundamental studies of the methodological challenges. Here, low-pressure sampling (ultra)long-path Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS) was applied with an effective optical path length of approximately 6.17 km. We studied three average amounts of ammonia: (38.2 ± 0.8) nmol/mol, (74.8 ± 0.7) nmol/mol, and (112.1 ± 1.2) nmol/mol. Furthermore, these amounts were investigated at trace-humidity levels ranging from 0.8 to 8.5 ppmV. We observed a systematic, nonlinear, and humidity-dependent positive measurement bias of up to + (1.0 ± 0.2) nmol/mol at the maximum investigated trace-humidity volume fraction of 8.5 ppmV. This bias was not caused by spectral interference but rather by water-induced accumulation of ammonia within the optical cavity. Moreover, time-resolved measurements in the presence of trace ammonia showed that water desorption follows first-order kinetics, whereas water adsorption followed mixed-order kinetics with an apparent reaction order of 1.57 ± 0.03. Distinct hydration states of surface-bound ammonia were identified, whereas under dry conditions and with increasing amounts of ammonia, enhanced surface adhesion through intermolecular clustering was observed. In addition, the presence of ammonium species within the sorption layer was indirectly confirmed by our experiments. In conclusion, we provide a deeper insight into trace-level ammonia–water interactions and establish a framework for optimizing methodologies, particularly for (ultra)long-path optical gas measurement systems.
KW - Ammonia
KW - Hydrogen
KW - OF-CEAS
KW - Humidity
KW - Surface Interactions
KW - Adsorption
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643627
DO - https://doi.org/10.1021/acsmeasuresciau.5c00105
SN - 2694-250X
SP - 1
EP - 15
PB - American Chemical Society (ACS)
AN - OPUS4-64362
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Moufid, M.
A1 - Tiebe, Carlo
A1 - El Bari, N.
A1 - Bartholmai, Matthias
A1 - Bouchikhi, B.
T1 - Characterization of Unpleasant Odors in Poultry Houses Using Metal Oxide Semiconductor-Based Gas Sensor Arrays and Pattern Recognition Methods
N2 - In this study, the ability of an electronic nose developed to analyze and monitor odor emissions from three poultry farms located in Meknes (Morocco) and Berlin (Germany) was evaluated. Indeed, the potentiality of the electronic nose (e-nose) to differentiate the concentration fractions of hydrogen sulfide, ammonia, and ethanol was investigated. Furthermore, the impact change of relative humidity values (from 15% to 67%) on the responses of the gas sensors was reported and revealed that the effect remained less than 0.6%. Furthermore, the relevant results confirmed that the developed e-nose system was able to perfectly classify and monitor the odorous air of poultry farms.
T2 - 1st International Electronic Conference on Chemical Sensors and Analytical Chemistry
CY - Online meeting
DA - 01.07.2021
KW - Pattern recognition methods
KW - Gas sensors
KW - Electronic nose
KW - poultry odorous air monitoring
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544005
UR - https://csac2021.sciforum.net/
DO - https://doi.org/10.3390/CSAC2021-10481
VL - 5
IS - 52
SP - 1
EP - 7
PB - MDPI
AN - OPUS4-54400
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Solberg, S.
A1 - Zimmermann, P.
A1 - Wilhelmsen, Ø.
A1 - Lamb, J.
A1 - Bock, Robert
A1 - Burheim, O.
T1 - Heat to Hydrogen by Reverse Electrodialysis—Using a Non-Equilibrium Thermodynamics Model to Evaluate Hydrogen Production Concepts Utilising Waste Heat
N2 - The reverse electrodialysis heat engine (REDHE) is a promising salinity gradient energy technology, capable of producing hydrogen with an input of waste heat at temperatures below 100 °C. A salinity gradient drives water electrolysis in the reverse electrodialysis (RED) cell, and spent solutions are regenerated using waste heat in a precipitation or evaporation unit. This work presents a non-equilibrium thermodynamics model for the RED cell, and the hydrogen production is investigated for KCl/water solutions. The results show that the evaporation concept requires 40 times less waste heat and produces three times more hydrogen than the precipitation concept. With commercial evaporation technology, a system efficiency of 2% is obtained, with a hydrogen production rate of 0.38 gH2 m−2h−1 and a waste heat requirement of 1.7 kWh g−1H2. The water transference coefficient and the salt diffusion coefficient are identified as membrane properties with a large negative impact on hydrogen production and system efficiency. Each unit of the water transference coefficient in the range tw=[0–10] causes a −7 mV decrease in unit cell electric potential, and a −0.3% decrease in system efficiency. Increasing the membrane salt diffusion coefficient from 10−12 to 10−11 leads to the system efficiency decreasing from 2% to 0.6%
KW - Non-equilibrium thermodynamics
KW - Hydrogen
KW - Waste heat
KW - RED
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556677
DO - https://doi.org/10.3390/en15166011
VL - 15
IS - 16
SP - 6011
PB - MDPI
AN - OPUS4-55667
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baglo, K.
A1 - Sauermoser, M.
A1 - Lid, M.
A1 - Paschke, T.
A1 - Bin Afif, A.
A1 - Lunzer, M.
A1 - Bock, Robert
A1 - Steinert, M.
A1 - Flaten, A.
A1 - Torgersen, J.
T1 - Overcoming the transport limitations of photopolymer-derived architected carbon
N2 - Photopolymer derived carbon grows in popularity, yet the range in available feature sizes is limited. Here we focus on expanding the field to low surface to volume ratio (SVR) structures. We describe a high temperature acrylic photopolymerizable precursor with FTIR and DSC and develop a thermal inert-gas treatment for producing architected carbon in the mm scale with SVR of 1.38 x10-3 μm-1. Based on TGA and MS, we distinguish two thermal regimes with activation energies of ~79 and 169 kJ mol-1, which we reason with mechanisms during the polymer’s morphologic conversion between 300 - 500 °C. The temperature range of the major dimensional shrinkage (300-440 °C, 50%) does not match the range of the largest alteration in elemental composition (440-600 °C, O/C 0.25-0.087%). The insights lead to an optimized thermal treatment with an initial ramp (2 °C min-1 to 350 °C), isothermal hold (14h), post hold ramp (0.5 °C min-1 to 440 °C) and final ramp (10 °C min-1 to 1000 °C). The resulting carbon structures are dimensionally stable, non-porous at the μm scale, and comprise an unprecedented variation in feature sizes (from mm to μm scale). The findings shall advance architected carbon to industrially relevant scales.
KW - Carbon
KW - Photopolymer
KW - Transport limitations
KW - Porous materials
KW - Additive manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575038
DO - https://doi.org/10.1002/admt.202300092
SN - 2365-709X
SP - 2300092
PB - Wiley-VCH GmbH
AN - OPUS4-57503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, David
A1 - Zscherpel, Uwe
A1 - Ewert, Uwe
T1 - Photon counting and energy discriminating x-ray detectors - benefits and applications
N2 - Since a few years the direct detection of X-ray photons into electrical signals is possible by usage of highly absorbing photo conducting materials (e.g. CdTe) as detection layer of an underlying CMOS semiconductor X-ray detector. Even NDT energies up to 400 keV are possible today, as well. The image sharpness and absorption efficiency is improved by the replacement of the unsharp scintillation layer (as used at indirect detecting detectors) by a photo conducting layer of much higher thickness. If the read-out speed is high enough (ca. 50 – 100 ns dead time) single X-ray photons can be counted and their energy measured. Read-out noise and dark image correction can be avoided. By setting energy thresholds selected energy ranges of the X-ray spectrum can be detected or suppressed. This allows material discrimination by dual-energy techniques or the reduction of image contributions of scattered radiation, which results in an enhanced contrast sensitivity. To use these advantages in an effective way, a special calibration procedure has to be developed, which considers also time dependent processes in the detection layer. This contribution presents some of these new properties of direct detecting digital detector arrays (DDAs) and shows first results on testing fiber reinforced composites as well as first approaches to dual energy imaging.
T2 - 19th World Conference on Non-Destructive Testing, 2016
CY - Munich, Germany
DA - 13.06.2016
KW - CFRP
KW - Photon counting detectors
KW - dual-energy
KW - laminography
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365744
SN - 978-3-940283-78-8
N1 - Geburtsname von Schumacher, David: Walter, D.
-
Birth name of Schumacher, David: Walter, D.
VL - 2016 / 158
SP - Tu.2.B.5
AN - OPUS4-36574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hosseini, Seyed M.H.
A1 - Ségur, D.
A1 - Boehm, Rainer
A1 - Gohlke, Dirk
A1 - Heckel, Thomas
A1 - Riemer, S.
A1 - Brackrock, Daniel
A1 - Gaal, Mate
T1 - Characterization and optimization of ultrasonic tests for inspection of fiber-reinforced plastic composites in energy related applications
N2 - Applications of fibre reinforced plastic (FRP) composites in modern industries are increasing due to their considerable advantages such as light weight and excellent mechanical properties. Accordingly, importance of operational safety of modern structures made of advanced composites by ensuring the material quality has led to increasing demands for development of non-destructive evaluation (NDE) systems. In the context of a European project entitled “Validated Inspection Techniques for Composites in Energy Applications” (VITCEA), the aim is to develop and validate traceable procedures for novel NDE techniques with contrasting damage detection capabilities in energy related applications such as wind and marine turbine blades, nacelles, oil and gas flexible risers. Accordingly, VITCEA focuses on optimization of ultrasonic tests (UTs) for quantitative defect detection and quality characterization of FRP structures. In this context, the present study describes the ultrasound field in heterogeneous composite materials. The theoretical predictions are compared with simulation results obtained from CIVA a software package dedicated to NDT simulations based on the asymptotic ray theory.
T2 - WCNDT 2016 - - 19th World Conference on Non-Destructive Testing
CY - München
DA - 13.06.2016
KW - Ultrasonic tests
KW - Composite
KW - Wave propagation
KW - Analytical approach
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-356398
SP - We.4.D.5, 1
EP - 8
AN - OPUS4-35639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rothbart, Nick
A1 - Maierhofer, Christiane
A1 - Goldammer, M.
A1 - Hohlstein, F.
A1 - Koch, J.
A1 - Kryukov, I.
A1 - Mahler, G.
A1 - Stotter, B.
A1 - Walle, G.
A1 - Oswald-Tranta, B.
A1 - Sengebusch, M.
T1 - A round robin test on flash thermography
N2 - A round robin test on flash thermography was organized within the scope of a standardization research project. This test gives information on reliability, comparability and efficiency of different testing situations. Data recorded on metal and CFRP test specimens with flat bottom holes (FBH) were analysed by evaluating the detectability and by calculating the signal-to-noise ratio (SNR) of the defect signatures as a function of defect parameters. For the investigation of the influence of material properties on the spatial resolution as well as on penetration depth, test specimens made of steel and copper with crossed notches and a notch ramp were constructed and investigated. Here, the minimum resolvable notch distance and the maximum detectable depth of the ramp were analysed.
T2 - 19th World Conference on Non-destructive Testing (WCNDT)
CY - Munich, Germany
DA - 13.06.2016
KW - Active thermography
KW - Flash excitation
KW - Round robin test
KW - Standardisation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366853
SN - 978-3-940283-78-8
VL - BB 158
SP - We.3.D.4., 1
EP - 8
PB - DGZfP
CY - Berlin
AN - OPUS4-36685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schadow, Florian
A1 - Gaal, Mate
A1 - Bartusch, Jürgen
A1 - Dohse, E.
A1 - Köppe, Enrico
T1 - Focusing air-coupled ultrasonic transducers based on ferroelectrets
N2 - Rising importance of composite lightweight structures in aircraft and automobile industries increases the demand on reliable non-destructive testing methods for these structures. Air-coupled ultrasonic testing emerged to suit these requirements as it does not require any liquid coupling medium. In conventional air-coupled ultrasonic transducers, matching layers are used in order to decrease the impedance mismatch between transducer and air. Matching layers can be omitted by using ferroelectrets, which are charged cellular polymers having ferroelectric and piezoelectric properties. Especially a low Young’s modulus, low density and low sound velocity of cellular polypropylene (cPP) are properties being required for well-matched air-coupled ultrasonic transducers.
In our contribution we show recent enhancements of cPP transducers resulting in focused sound fields and thus improved lateral sensitivity. The influence of different transmitter apertures was evaluated using measurements of the emitted sound field. Further we show a transmission of a test specimen of carbon-fiber-reinforced plastic (CFRP) containing artificial damages. Results of focused transducers were compared to planar ferroelectret transducers, as well as to conventional air-coupled transducers.
T2 - 19th World Conference on Non-Destructive Testing 2016
CY - München, Germany
DA - 13.06.2016
KW - Air-coupled ultrasonic testing
KW - Ferroelectrets
KW - Cellular polypropylene
KW - Focused sound fields
KW - Focused transducers
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355116
UR - http://www.ndt.net/search/docs.php3?showForm=off&id=19453
SP - 1
EP - 8
AN - OPUS4-35511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Röllig, Mathias
A1 - Worzewski, Tamara
A1 - Doroshtnasir, Manoucher
T1 - Thermographic rotor blade inspection from larger distances – a promising tool for the maintenance of wind turbines
N2 - The permanently increasing number of wind turbines requires suited inspection and monitoring methods to ensure liability and security. Concerning the inspection of ro-tor blades, only manual inspections are state of the art. Thermographic Testing (TT) has the potential to detect typical failures and damages on rotor blades. The paper presents some results of onsite measurements carried out as “passive thermogra-phy”, i.e. without a defined heating procedure. Due the totally contactless meas-urement principle, TT can be applied to rotating blades as well as to resting blades. Both methods will be compared with respect to their possible realization.
T2 - WCNDT 2016
CY - Munich, Germany
DA - 13.06.2016
KW - Wind turbine rotor blade
KW - Thermographic inspection
KW - Passive thermography
KW - Nondestructive testing
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366331
SN - 978-3-940283-78-8
SP - We.4.D.4., 1
EP - 8
AN - OPUS4-36633
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Knöppchen, Andreas
A1 - Pohl, Rainer
A1 - Zimne, Lutz
A1 - Bode, Johannes
A1 - Hollesch, Martin
T1 - Manufacturing of reference defects for NDT using low-energy EDM
N2 - For non-destructive testing (NDT) appropriate reference blocks are required in order to verify and calibrate a testing procedure. At BAM a special electric discharge machining (EDM) system has been developed which is able to manufacture artificial defects having a width down to 30 μm.
Especially in the case of austenitic materials conventional EDM leads to a transformation of austenite to martensite. The martensite transformation causes a higher sensitivity of electromagnetic NDT methods (e. g. eddy current testing) at the artificial defects compared to natural defects of same size. The EDM system developed at BAM uses very low energy to avoid this material transformation. A side effect of the low-energy EDM is a lower surface roughness compared to conventional EDM. The artificial defects manufactured at BAM are measured optically and delivered with a certificate. A comparison of artificial defects shows the influence of material transformation on NDT and how differently the quality of the artificial defects can be.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Reference defect
KW - EDM
KW - Electric discharge machining
KW - Artificial defect
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365995
SN - 978-3-940283-78-8
VL - 157
SP - 1
EP - 10
PB - German Society for Non-Destructive Testing (DGZfP e.V.)
CY - Berlin, Germany
AN - OPUS4-36599
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlke, Dirk
A1 - Boehm, Rainer
A1 - Perez-Alonso, M.
T1 - A comparison between ASTM E588 and SEP 1927 relating resolution limits at determination of the purity grade
N2 - With increased usage of highly demanded, modern materials on safety
relevant parts (e.g. railway wheel sets, generator shafts, turbine disks, medical
implants, etc.) comprehensive analyses regarding the quality of the material are
requested. This gives a focus to non-destructive methods using ultrasound immersion
tank testing for classifying the degree of purity. Two autonomous standards,
ASTM E588 and SEP 1927, have been established for the definition, execution and
evaluation for this high resolution ultrasonic measurements on steel products.
The propagation of ultrasonic waves and the resulting sound field are strongly
dependent on the acoustical properties of the inspected material and the geometry
of probes and specimen. The definition of the measurement setup and the evaluation
methods appear to differ significantly in the given standards. ASTM E588 and
SEP 1927 prescribe the requirement for surface roughness and probe selection, are
using threshold based methods for cleanliness detection, but differ in computation
for the degree of purity. This has been the motivation for a comparison between
both standards with the main focus on amplitude depth dependency and overall spatial
resolution taking the influence of different material characteristics, geometry of
the specimen and sound fields into account.
A performance comparison between the use of non-focusing and focusing probes
respective to the threshold based detection will be presented in this contribution. In
addition, the usage of complex reconstruction algorithms (e.g. SAFT, echo tomography)
is compared with the traditional approaches of inclusion detection and
estimation of the degree of purity
T2 - 19th World Conference on Non-Destructive Testing 2016
CY - Munich, Germany
DA - 13.06.2016
KW - Ultrasonic immersion tank testing
KW - Purity grade
KW - Material characterisation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-382972
SP - Paper X15, 1
EP - 10
AN - OPUS4-38297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schukar, Vivien
A1 - Köppe, Enrico
A1 - Hofmann, Detlef
A1 - Westphal, Anja
A1 - Sahre, Mario
A1 - Gong, Xin
A1 - Bartholmai, Matthias
A1 - Beck, Uwe
T1 - Magnetic field detection with an advanced FBG-based sensor device
N2 - A high-performance fiber Bragg grating-based (FBG) sensor device has been developed for the detection of small magnetic fields. Based on a smart multilayer jacket around the fibre over the physical length of the FBG, magnetic fields generated by rotating machine parts, power generators or power cable can be easily detected, analysed and evaluated. Consequently, this innovative, on-line and non-contact inspection method results in an increase in quality and reliability of high-performing machine parts, devices and cables. The basic physical principle is based on a magnetostrictive multilayer system that strains the high-resolution FBG element in presence of magnetic fields. Subsequently, a fixed relationship between induced magnetic field and wavelength change of the FBG element describes the characteristic sensitivity curve. Intensive tests regarding characterisation of this magnetic field FBG sensor have been carried out and its performance has been evaluated.
T2 - 30th Eurosensors Conference, EUROSENSORS 2016
CY - Budapest, Hungary
DA - 04.09.2016
KW - Fiber Bragg grating
KW - Magnetostriction
KW - Strain
KW - Magnetic field
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376703
DO - https://doi.org/10.1016/j.proeng.2016.11.445
SN - 1877-7058
VL - 168
SP - 1270
EP - 1274
PB - Elsevier Ltd.
AN - OPUS4-37670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlke, Dirk
A1 - Heckel, Thomas
T1 - Three dimensional examination of directivity pattern in immersion tank testing
N2 - High resolution examination of safety-relevant parts in immersion tank testing with focussing probes is forming a main topic of modern non-destructive testing. For the usage of complex reconstruction methods and algorithms, an individual and detailed knowledge about the transmission behaviour of the used probes is essential, as this has a significant influence on the results of data reconstruction.
Especially the knowledge about position and diameter of the focal point is needed to achieve the highest possible sensitivity. Through the individual position of the beam axis within the examined volume, a four dimensional metro logical determination of the acoustical pressure (x, y, z, t) is necessary. With the measured data it is possible to draw interferences about the sound field and acoustical pressure distribution. The presented work realized a method of automatic determination of the beam axis, the position of focal point and the focal diameter to support individual testing setups and transducer characterization.
T2 - 7th International Symposium on NDT in Aerospace
CY - Bremen, Germany
DA - 16.11.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-339995
AN - OPUS4-33999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ziegler, Mathias
A1 - Thiel, Erik
A1 - Studemund, Taarna
T1 - Laser-Thermografie – Von der flächigen zur strukturierten Anregung
N2 - Im Bereich der optisch angeregten Thermografie haben sich Blitzlampen (impulsförmig-flächige Erwärmung) und Halogenlampen (moduliert-flächige Erwärmung) für die spezifischen Regime Impuls- und Lockin-Thermografie etabliert.
Mittels eines rasternden fokussierten Lasers wird die Flying-spot Laserthermografie z.B. zur Risserkennung (Dauerstrichbetrieb) und die photothermische Materialcharakterisierung (hochfrequent moduliert)implementiert. Durch die Verfügbarkeit neuer Technologien (schnelle und hochauflösende IR-Kameras, brillante innovativer Lichtquellen und performante Datenakquisitions- und Verarbeitungstechnik) wird ein Paradigmenwechsel von den getrennt voneinander stehenden photothermischen und
thermografischen Techniken hin zu einer einheitlichen quantitativen Mess-und Prüftechnik ermöglicht, die schneller und präziser ist. Ähnlich wie ein LED-Array, jedoch mit einer um zwei Größenordnungen höheren Bestrahlungsstärke, steht jetzt eine neuartige brillante Laserquelle, das VCSEL-Array (vertical-cavity surface-emitting laser) zur Verfügung, welches die starke Beschränkung der zeitlichen Dynamik der etablierten Lichtquellen aufhebt und gleichzeitig spektral sauber von der Detektionswellenlänge getrennt ist. Es vereint somit das schnelle zeitliche Verhalten eines Diodenlasers mit der hohen optischen Bestrahlungsstärke und dem großen Beleuchtungsbereich von Blitzlampen. Darüber hinaus kann die Erwärmung auch strukturiert vorgenommen werden, da einzelne Bereiche des VCSEL-Arrays unabhängig voneinander angesteuert werden können. Dieser neue Freiheitsgrad ermöglicht die Entwicklung ganz neuer thermografischer ZfP-Verfahren.
T2 - Thermographie-Kolloquium 2017
CY - Berlin, Germany
DA - 28.09.2017
KW - Thermografie
KW - Laser
KW - Zerstörungsfreie Prüfung
KW - Lock-in
KW - VCSEL
KW - Photothermisch
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-431170
UR - https://www.dgzfp.de/Portals/thermo2017/BB/6.pdf
SN - 978-3-940283-88-7
VL - 163
SP - 1
EP - 15
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-43117
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schadow, Florian
A1 - Brackrock, Daniel
A1 - Gaal, Mate
A1 - Heckel, Thomas
T1 - Ultrasonic inspection and data analysis of glass- and carbon-fibre-reinforced plastics
N2 - Non-destructive testing (NDT) helps to find material defects without having an influence on the material itself. It is applied as a method of quality control, for online structural health monitoring, and for inspection of safety related components. Due to the ability of automation and a simple test setup ultrasonic testing is one major NDT technique next to several existing options. Whereas contact technique allows the use of higher frequencies of some MHz and phased array focusing, air-coupled ultrasonic testing (ACUT) shows different advantages. Most significant for ACUT is the absence of any coupling fluid and an economical test procedure respective time and costs. Both contact technique and ACUT have been improved and enhanced during the past years. One important enhancement is the development of airborne transducers based on ferroelectrets, like charged cellular polypropylene (cpp), which makes the application of any matching layers being mandatory in conventional piezoelectric transducers unnecessary. In this contribution we show ultrasonic inspection results of specimens made of carbon- and glass-fibre-reinforced plastic. These specimens include defects represented by drill holes and artificial delaminations of various size and depth. We compare inspection results achieved by using contact technique to those achieved by ACUT. For ACUT, conventional piezoelectric transducers and transducers based on cpp were used, both focused as well as non-focused types. Contact inspections were performed with a multi-channel matrix array probe. Once the inspection data is recorded it can be analysed in order to detect and evaluate defects in the specimen. We present different analysing strategies and compare these regarding detection rate and sizing of defects.
T2 - 3rd International Symposium on Fatigue Design and Material Defects, FDMD 2017
CY - Lecco, Italy
DA - 19.09.2017
KW - Ultrasonic testing
KW - Air-coupled
KW - Carbon-fibre-reinforced plastic
KW - Glass-fibre-reinforced
KW - Material inspection
KW - Defect sizing
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434802
DO - https://doi.org/10.1016/j.prostr.2017.11.092
SN - 2452-3216
VL - 7
SP - 299
EP - 306
PB - Elsevier B.V.
AN - OPUS4-43480
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schumacher, David
A1 - Ewert, Uwe
A1 - Zscherpel, Uwe
T1 - Influencing parameters on image quality using photon counting detectors for laminography
N2 - Classical film radiography is a well-established NDT technique and it is most commonly used for testing weld seams and corroded pipes e.g. in oil and gas industry or in nuclear power plants. In the course of digitization, digital detector arrays (DDA) are finding their way into industrial applications and are replacing film radiography step by step. This study deals with the latest generation of DDAs, the photon counting and energy resolving detectors (PCD), and their characteristics compared to charge integrating detectors (CID). No matter which technology to use, radiography still lacks a general issue: A three-dimensional object is projected onto a two dimensional image. Of course, advanced computed tomography (CT) algorithms exist since many years, but if the object to investigate is too large to fit into the manipulation system or its shape is not appropriate, CT is not feasible or sensible to be applied. To overcome this limitation, numerous laminographic algorithms have been developed in the past. In this study, photon counting detectors are used in combination with co-planar translational laminography to gain reconstructed three-dimensional volumes. Both laminographic testing and PCDs require a serious knowledge of many parameters that can influence the image quality in the resulting datasets. These are e.g. the detector efficiency and calibration procedure, setting of energy thresholds, exposure data, number of projections, beam length correction and spatial resolution. The use of PCDs yields more variables to be considered compared to CIDs. The most important parameters in laminographic testing and in the use of PCDs are described in this study and limits are discussed.
T2 - 7th European-American Workshop on Reliability of NDE
CY - Potsdam, Germany
DA - 05.09.2017
KW - X-ray imaging
KW - Digital radiography
KW - Co-planar translational laminography
KW - Reliability
KW - Photon counting detectors
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428912
UR - http://www.nde-reliability.de/portals/nde17/BB/31.pdf
SP - Paper 31, 1
EP - 11
AN - OPUS4-42891
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Vollert, F.
A1 - Dixneit, Jonny
A1 - Gibmeier, J.
ED - Marais, D.
ED - Holden, T.M.
ED - Venter, A.M.
T1 - Effect of Residual Stress Relaxation due to Sample Extraction on the Detectability of Hot Crack Networks in LTT Welds by means of µCT
N2 - Investigations on weldability often deal with hot cracking as one of the most prevalent failure mechanisms during weld fabrication. The modified varestraint transvarestraint hot cracking test (MVT) is well known to assess the hot cracking susceptibility of materials. The shortcoming of this approach is that the information is only from the very near surface region which inhibits access to the characteristic of the hot crack network in the bulk. Here, we report about an alternative approach to monitor the entire 3D hot crack network after welding by means of microfocus X-ray computer tomography (µCT). However, to provide sufficient high spatial resolution small samples must be sectioned from the MVT-welded joint. The sampling is accompanied by local relaxation of the residual stress distributions that are induced by welding, which can have an impact on the crack volumes prior to the sampling. The studies were carried out to investigate the hot cracking susceptibility of low transformation temperature filler materials (LTT). As high compression residual stresses up to -600 MPa in the area of the crack networks were determined by means of the contour method, stress relaxation caused by sectioning for µCT sample extraction can affect the detectability of the cracks later on. X-ray diffraction studies revealed surface residual stress relaxations up to about 400 MPa due to cutting. To investigate this effect, the specimens with hot cracks were subjected to a load test with known stress states. The results clearly show that local stress relaxations will have a strong impact on the volume images reconstructed from tomography analysis. This effect must be considered during hot crack assessment on basis of µCT data.
T2 - 9th International Conference on Mechanical Stress Evaluation by Neutron and Synchrotron Radiation (MECA SENS 2017)
CY - Skukuza Rest Camp, South Africa
DA - 19.09.2017
KW - LTT Weld Filler Materials
KW - µCT-analysis
KW - Hot Cracks
KW - Welding
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456765
SN - 978-1-945291-66-1
DO - https://doi.org/10.21741/9781945291678-13
SN - 2474-395X
VL - 4
SP - 85
EP - 90
AN - OPUS4-45676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Guhl, Svetlana
A1 - Meyer, Klas
A1 - Kern, Simon
A1 - Gräßer, Patrick
A1 - Maiwald, Michael
ED - Maiwald, Michael
T1 - Process monitoring of an intensified continuous production unit with compact NMR spectroscopy
N2 - Monitoring chemical reactions is the key to chemical process control. Today, mainly optical online methods are applied. NMR spectroscopy has a high potential for direct loop process control. Compact NMR instruments based on permanent magnets are robust and relatively inexpensive analyzers, which feature advantages like low cost, low maintenance, ease of use, and cryogen-free operation. Instruments for online NMR measurements equipped with a flow-through cell, possessing a good signal-to-noise-ratio, sufficient robustness, and meeting the requirements for integration into industrial plants (i.e., explosion safety and fully automated data analysis) are cur-rently not available off the rack. Recently, promising benchtop NMR instruments with acceptable performance came to market and process integrated sensors developed on basis of such laboratory instruments are on their way.
T2 - 12. Kolloquium des Arbeitskreises Prozessanalytik
CY - Berlin, Germany
DA - 28.11.2016
KW - Online NMR spectroscopy
KW - Modular production units
KW - Low field NMR spectroscopy
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-383646
SP - P17, 75
EP - 77
AN - OPUS4-38364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, Daniel
A1 - Müller, Christina
A1 - Pitkänen, J.
T1 - Konzept für den Einsatz der Bayes'schen Statistik: In der Zuverlässigkeitsbestimmung von zerstörungsfreien Diagnosesystemen - Das Problem zu kleiner experimenteller Datenmengen
N2 - Die statistische Qualitätskennzahl 'Probability of Detection (POD)' hängt von der Anzahl der zugrunde liegenden, brauchbaren Ergebnisse ab. Ist die Datenmenge niedrig, so ist auch die Aussage der POD eher beschränkt. Dennoch heißt eine große Zahl von Daten, nicht gleichzeitig, dass die POD für den realen Einsatz in der Produktion genügt. Es muss unterschieden werden, auf welcher Basis unter welchen konkreten Bedingungen - die Daten erhoben wurden. Als wichtigste Ergebnisse zählen die Messergebnisse aus der Produktion der später verwendeten Prüfobjekte für den konkreten Einsatz. Noch bevor die zerstörungsfreien Prüfmethoden zuverlässig in der Produktion eingesetzt wurde, muss jedoch nachgewiesen werden, dass die real vorkommenden Fehler gefunden werden können. Das bedeutet, zu einem Zeitpunkt, an dem noch nicht ausreichend Daten vorhanden sind. Während für die realistische Prüfung die notwendige Anzahl der verschiedenen Fehler meist nicht erreicht wird, so fehlen bei der Bewertung der künstlichen Fehler wichtige Parameter und Einflussgrößen. Es muss somit eine Zwischenlösung gesucht werden, in der die Informationen von beiden Prüfungen kombiniert werden. Mit der Bayesschen Statistik ermöglicht die Mathematik diese Informationen miteinander zu kombinieren und somit beide Informationen mit in die Bewertung einfließen zu lassen.
Praktisch angewandt und erprobt wird die Vorgehensweise gemeinsam mit der Firma POSIVA, die sich mit dem Bau eines Endlagers für hoch-radioaktiven Abfall in Finnland beschäftigt. Hier wird als eine der technischen Barrieren ein Kupferbehälter für die Aufbewahrung der verbrauchten Brennstäbe genutzt. Dieser Kupferbehälter wird mit mehreren zerstörungsfreien Prüfmethoden geprüft. Anhand von Radiographiedaten wird gezeigt, dass die Aussagekraft der realistischen Fehlerdaten mit Hilfe der künstlichen Referenzfehlerdaten untermauert werden kann.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Bayes'sche Statistik
KW - POD
KW - Fehlende Datenmenge
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-251598
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Mi.3.C.3)
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25159
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Christina
A1 - Pavlovic, Mato
T1 - Ganzheitliche Zuverlässigkeit - Prüfung von Bauteilen mit komplexer Geometrie
N2 - Selbst die modernsten ZfP-Systeme können, wenn sie bis an die Grenzen ihrer Möglichkeiten z. B. kleine Fehler zu finden beansprucht werden, nicht alle Fehler der gleichen Größe finden. Sogar wenn ein und derselbe Fehler mehrmals geprüft wird, wird er nicht immer gefunden. Deshalb wurde, besonders für solche Anwendungsfälle wo das Übersehen eines Fehlers zu schwerwiegenden Konsequenzen führt, das Konzept der Zuverlässigkeit der ZfP eingeführt. Das Konzept der BAM beinhaltet eine ganzheitliche Betrachtungsweise mittels eines modularen Models. Die Hauptmodule des Modells sind die innewohnende Fähigkeit, die die physikalisch technischen Aspekte behandelt. Weiterhin werden die Einflüsse der Umgebung betrachtet, die den Prüfprozess stören, aber nicht zum Prüfsystem selbst gehören. Einen wesentlichen Aspekt, sowohl bei manuellen als auch bei mechanisierten Prüfungen stellt der menschliche Faktor dar. Die Betrachtungen im vorliegenden Artikel beziehen sich hauptsächlich auf die innewohnende Fähigkeit.
Wegen der dem Prüfprozess innewohnenden Unsicherheit wird die Leistungsfähigkeit eines ZfP-Systems durch eine Funktion POD (a) ausgedrückt. Zu verschiedenen Fehlergrößen (a) gehören verschiedene Fehlerauffindwahrscheinlichkeiten (POD). Die Fehlergröße (a), bei der die untere 95 % Vertrauensgrenze das Niveau von 90 % POD schneidet wird α90/95 genannt. Dieser Punkt wird als Maß für das Leistungsvermögen der ZfP-Methode benutzt.
Während der letzten 10-20 Jahre wurden auf diese Weise verschiedene Inspektionssysteme für eine gewählte ZfP-Methode mit einer einfachen Anwendungsgeometrie bewertet.
Wenn man über diese einfachen Anwendungssituationen hinaus, die Zuverlässigkeit in realen industriellen Prozessen betrachtet, treten als erstes industrielle Bauteile mit komplexer Geometrie und Defekte, die mit mehr als nur einem Parameter (Größe und Tiefe, Orientierung, Oberflächenrauhigkeit) charakterisiert werden müssen, auf die Tagesordnung. Neue hochentwickelte und automatisierte ZfP-Systeme, wie z. B. Ultraschallgruppenstrahler, lassen die Möglichkeit zu die Prüfungen digital aufzuzeichnen und später erst auszuwerten. Weiterhin erlauben es moderne Modellierungswerkzeuge den ZfP-Prozess zu simulieren und damit die Einflüsse der Wellenausbreitung und deren Wechselwirkung mit Defekten sowie die Wirkung der zusätzlichen Einflussparameter (z. B. Abstand vom Prüfkopf oder Orientierung) auf die POD zu untersuchen. Damit entsteht die Möglichkeit die räumliche Verteilung der POD im Prüfstück zu ermitteln die Volumen-POD. Die Volumen-POD kann ebenso wie die konventionelle POD als Maß für die Leistungsfähigkeit des ZfP-Systems benutzt werden. Darüber hinaus kann man das ZfP-System optimieren. Wenn z. B. bestimmte Volumenelemente nur ungenügende POD-Werte aufweisen, müssen zusätzliche Prüfungen einbezogen werden. Aber auch der umgekehrte Fall, Bereiche in denen mehrere Prüfköpfe ein POD Niveau von 100 % haben und die Zahl der Prüfungen reduziert werden kann, werden mit der Volumen-POD erkannt.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Zuverlässigkeit
KW - ZfP
KW - Volumen-POD
KW - Produkt-Design
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-251607
SN - 978-3-940283-33-7
VL - 127
SP - Mi.3.C.1 - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25160
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Feistkorn, Sascha
A1 - Taffe, Alexander
T1 - Die POD - eine Vorgehensweise zum qualitativen Gütenachweis zerstörungsfreier Prüfverfahren im Bauwesen am Beispiel des Impulsradars
N2 - Die POD (Probability of Detection) hat sich als statistisches Werkzeug für die Bewertung der Zuverlässigkeit zerstörungsfreier Prüfsysteme in der klassischen ZfP bewährt. Aus diesem Grund wird die Methode der POD auf die zerstörungsfreie Prüfung im Bauwesen übertragen, um erstmals eine objektive Antwort auf zerstörungsfreie Prüfungen geben zu können, denen eine qualitative Fragestellung zugrunde liegt. Dies geschieht an der Prüfaufgabe der Ortung metallischer Reflektoren in Abhängigkeit Ihrer Tiefenlage mithilfe des Impulsradars. Dazu wird nachgewiesen, dass eine Übertragung und Anwendung der POD für die objektive Bewertung dieser Prüfaufgabe zulässig ist. Nach der Konzipierung und Fertigung von Testkörpern werden die Ergebnisse der POD(a)-Analyse vorgestellt, die erstmal eine Charakterisierung und einen Vergleich unterschiedlicher Radarprüfsysteme anhand eines objektiv ermittelten Kennwerts ermöglichen. Außerdem können Einflussgrößen auf die Detektionstiefe eines metallischen Reflektors erstmals quantifiziert werden.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Impulsradar
KW - Probability of detection
KW - POD
KW - ZfPBau
KW - Gütenachweis
KW - Qualitative Prüfaufgabe
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-248866
SN - 978-3-940283-33-7
IS - DGZfP-BB 127
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24886
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ehrig, Karsten
A1 - Bartscher, M.
A1 - Goebbels, Jürgen
A1 - Koch, M.
A1 - Staude, Andreas
T1 - Einfluss von Materialkombinationen auf das dimensionelle Messen mit Mikro-Computertomographie am Beispiel eines werkstücknahen Testkörpers
N2 - Die Computertomographie (CT) hat sich als dimensionelle Messmethode in der industriellen Produktion etabliert. Durch Messungen an speziellen Prüfkörpern ist es möglich, quantitative Informationen über die metrologischen Eigenschaften dimensioneller Messungen zu erhalten. In dieser Arbeit wird einen Aluminium-Guss-Prüfkörper (120 mm x 90 mm x 60 mm) benutzt, mit dem – in der vorliegender Form – auch der Einfluss von Materialien unterschiedlicher Schwächung auf dimensionelle CT-Messungen untersucht werden kann. Der Prüfkörper ist in vier Segmente zerteilt, so dass auch innenliegende, raue Gussfreiformflächen der taktilen Koordinatenmessung zugänglich sind. Durch adaptierte Rubinkugeln als Referenzstrukturen können die CT-Messdaten in taktile Referenz-Koordinatensysteme überführt werden. Um den Einfluss von Materialien unterschiedlicher Schwächung auf das dimensionelle Messen mit CT zu untersuchen, wurden stärker schwächende ZTA-Störkugeln (Zirconia Toughened Alumina) mit zur Ausrichtung geeigneter Symmetriebrechung in der Nähe von ausgewählten taktilen Messstellen angebracht.
Zur Bewertung der Messabweichungen dienen taktile Referenzmessungen an den ZTA-Kugeln sowie taktile Messungen an den Freiformflächen des Gussteils, wobei durch ein iteratives Antastverfahren eine verbesserte Erfassung der Geometrie auch bei starken lokalen Oberflächenkrümmungen sichergestellt wird.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Mikro-CT
KW - Dimensionelles Messen
KW - Testkörper
KW - Multimaterial
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-248878
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.1.B.2)
SP - 1
EP - 6
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24887
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ortwein, Hans-Peter
A1 - Bohse, Jürgen
A1 - Trappe, Volker
A1 - Hickmann, Stefan
T1 - Untersuchung des Zwischenfaserrisswachstums in Faserverbundwerkstoffen mit Schallemissions- und Röntgenrefraktionsverfahren
N2 - Hinsichtlich Materialermüdung und Betriebsfestigkeit in Faserkunststoffverbunden besteht - verglichen mit anderen Aspekten des Faserverbundleichtbaues – noch erheblicher Forschungsbedarf. Schon weit vor den globalen Festigkeiten des Laminates treten eine Vielzahl von Zwischenfaserbrüchen und vereinzelte Faserbrüche auf. Die Dichte dieser Mikrorisse soll hier als Indikator für den Zustand des Verbundes genutzt werden. Ihre Ermittlung stellt insbesondere bei Kohlenstofffasern eine Herausforderung dar. Über vergleichende Messungen mit der Schallemissionsanalyse (SEA) und der Röntgenrefraktionsscans (RR) wird die Entwicklung der Rissdichte bei Belastung untersucht. Die SEA zeichnet die Entstehung der Risse auf und kann wegen der kompakten Messtechnik auch gut am Bauteil eingesetzt werden. Die RR beobachtet die Änderung der inneren Grenzflächen, die ebenfalls die Entwicklung der Rissdichte widerspiegelt. Sie ist allerdings zurzeit nur als Laborverfahren geeignet. Der Vortrag berichtet(e) über den aktuellen Stand des vergleichenden Einsatzes beider Verfahren an Flachproben und innendruckbelasteten Rohrproben.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Deutschland
DA - 30.05.2011
KW - Schallemissionsprüfung
KW - Röntgenrefraktionsmessung
KW - Faserkunstoffverbund
KW - Druckbehälter
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-248913
SN - 978-3-940283-33-7
SP - Mi.4.A.1 - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24891
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachsmuth, Janne
A1 - Bohse, Jürgen
T1 - Schallemissionsanalyse von Schadensmechanismen an Feinkornstahl
N2 - In dieser Arbeit werden geschweißte Platten aus dem Feinkornstahl P460NL1 untersucht. Korrosion und Ermüdungsrisswachstum werden als Schadensmechanismen in das Material eingebracht und auf ihre Nachweisbarkeit in Plattenversuchen geprüft. Die Schallemissionssignale wurden nach primären und sekundären Quellmechanismen getrennt und ihr Einfluss auf die Gesamtemission analysiert.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-248902
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.2.C.2)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24890
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Röllig, Mathias
A1 - Steinfurth, Henrik
A1 - Ziegler, Mathias
A1 - Heck, S.J.
A1 - Scheuerlein, C.
T1 - Aktive Thermografie zur zerstörungsfreien Prüfung von Lötverbindungen
N2 - In diesem Beitrag werden die Möglichkeiten der Ortung von Fehlstellen in Cu Lötverbindungen unterhalb verschiedener Cu Blechdicken mit aktiver Thermografie demonstriert. Dabei wurden die Anregung mit Blitzlicht und die periodische Anregung mit der Lock-In Technik miteinander verglichen. Die Vor- und Nachteile der Anwendung unterschiedlicher IR-Kamerasysteme, einer gekühlten InSb-Quantendetektor IR-Kamera und einer Mikrobolometer IR-Kamera, werden dargestellt. Als objektives Kriterium wurde das SNR für unterschiedliche Fehlstellengrößen herangezogen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Aktive Thermografie
KW - Blitzlichtanregung
KW - Lock-In Anregung
KW - Lötverbindung
KW - Kupfer
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-249935
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (Di.1.C.1)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-24993
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bertovic, Marija
A1 - Müller, Christina
A1 - Kanzler, Daniel
A1 - Fahlbruch, B.
A1 - Pitkänen, J.
A1 - Ronneteg, U.
T1 - 'Human factors' bei der Datenauswertung der zerstörungsfreien Prüfung am Beispiel der nuklearen Endlagerung
N2 - Für eine ganzheitliche Betrachtung der Sicherheit bei der zerstörungsfreien Prüfung (ZfP) ist es unvermeidlich neben der Technik auch den Prüfer und die Prüforganisation einzubeziehen. Die Prüfung der Unversehrtheit von Endlagerbehältern ist eine eine sicherheitstechnisch wichtige Anwendung. Die Betreiber der geplanten finnischen und schwedischen Endlager, Posiva und SKB, kapseln den radioaktiven Abfall in Kupferkanistern ein und deponieren die Kanister dann in Felsgestein in einer Tiefe von ca. 500m. Die Kanister bestehen aus einem zylinderförmigen Kupfermantel mit einem Deckel und einem Boden, die zusammen die Außenumhüllung ergeben sowie einer Gusseisenmatrix für die Brennstäbe. Alle Komponenten werden auf ihre Dichtheit bzw. strukturelle Unversehrtheit mittels zerstörungsfreier Prüfmethoden geprüft, um sicher zu stellen, dass im Material und in den Schweißnähten keine kritischen Defekte vorhanden sind, die zu Freisetzungen in die Umgebung führen könnten. Vier ZfP Methoden (Ultraschall-, Wirbelstrom- und radiographische Prüfung, und die visuelle Prüfung anhand einer Kamera) werden mechanisiert durchgeführt, die gewonnenen Daten werden von qualifizierten Fachleuten ausgewertet und bieten so die Möglichkeit, dass Fehler entstehen.
Das 'Human Factor'- Untersuchungskonzept besteht aus der Identifizierung potenzieller menschlicher Fehler, deren Ursachen und Präventionsmethoden. Mit Hilfe einer abgewandelten FMEA (Failure Modes and Effects Analysis) wurden mögliche Risiken identifiziert, die die Wahrscheinlichkeit für das Auftreten menschlicher Fehler bei
der Datenauswertung erhöhen. Einige dieser Risiken sind beispielsweise
Verantwortungsdiffusion beim 4-Augen-Prinzip, Übervertrauen in die Technik bei der automatischen Identifikation von Defekten sowie der Aufmerksamkeitsverlust bei dynamischer Bildbetrachtung. Deren Wirkung wird derzeit experimentell überprüft, um Ansatzpunkte für Optimierungen zu ermitteln und damit die Gesamtzuverlässigkeit des Systems zu verbessern.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Human factors
KW - UT
KW - ET
KW - ZfP
KW - Nukleare Endlagerung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-251584
UR - http://jt2011.dgzfp.de/Portals/jt2011/BB/p42-ku~1.pdf
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (P 42)
SP - 1
EP - 2
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25158
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ehlert, Christopher
A1 - Holzweber, Markus
A1 - Lippitz, Andreas
A1 - Unger, Wolfgang
A1 - Saalfrank, Peter
T1 - A detailed assignment of NEXAFS resonances of imidazolium based ionic liquids
N2 - In Near Edge X-Ray Absorption Fine Structure (NEXAFS) spectroscopy X-Ray photons are used to excite tightly bound core electrons to low-lying unoccupied orbitals of the system. This technique offers insight into the electronic structure of the system as well as useful structural information. In this work, we apply NEXAFS to two kinds of imidazolium based ionic liquids ([CnC₁im]⁺[NTf₂]⁻ and [C₄C₁im]⁺[I]⁻). A combination of measurements and quantum chemical calculations of C K and N K NEXAFS resonances is presented. The simulations, based on the transition potential density functional theory method (TP-DFT), reproduce all characteristic features observed by the experiment. Furthermore, a detailed assignment of resonance features to excitation centers (carbon or nitrogen atoms) leads to a consistent interpretation of the spectra.
KW - Ionic liquids
KW - NEXAFS
KW - DFT spectrum simulations
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367223
DO - https://doi.org/10.1039/c5cp07434g
SN - 1463-9076
SN - 1463-9084
VL - 18
IS - 12
SP - 8654
EP - 8661
PB - Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-36722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Hickmann, Stefan
A1 - Kupsch, Andreas
A1 - Müller, Bernd R.
A1 - Laquai, René
A1 - De Monte, M.
T1 - Risse an gekerbten kurzglasfaserverstärkten Thermoplasten zerstörungsfrei charakterisiert mit Röntgenverfahren
N2 - Proben mit einer Mittelkerbe aus Polyamid 66 mit 35% Gewichtsan-teil an Kurzglasfaser (PA-GF35) wurden im Spritzgießverfahren hergestellt und in einem ungeschädigten und durch Schwingbeanspruch geschädigten Zustand mittels Röntgenverfahren charakterisiert. Sowohl die Faserorientierungsverteilung als auch die Riss-/Mikrorissbildung wurden mit der Röntgenrefraktionstopographie in einem SAXS-Aufbau und dem Diffraction-Enhanced-Imaging am Synchrotron (BESSY II) analysiert. Beide Verfahren spiegeln in guter Übereinstimmung die Charakteristiken dieser Werkstoffklasse in Bezug auf die Fertigungsqualität und die Schädigungsme-chanismen wider.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Kurzfaserverstärktes Polyamid
KW - Röntgenverfahren
KW - Rissfortschritt
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435659
UR - https://www.dgzfp.de/Dienste/Publikationen?kategorie=Berichtsb%C3%A4nde
SN - 978-3-940283-85-6
VL - 2017
SP - 1
EP - 11
PB - DGZfP
CY - Berlin
AN - OPUS4-43565
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Lange, Axel
A1 - Kupsch, Andreas
A1 - Hentschel, Manfred P.
A1 - Lück, S.
A1 - Schmidt, V.
A1 - Grothausmann, R.
A1 - Hilger, A.
A1 - Manke, I.
T1 - Reduzierung von Missing-Wedge-Artefakten mit DIRECTT
N2 - Wir stellen eine Prozedur vor, mit der typische 'Missing Wedge' (MW)-Artefakte in CT-Rekonstruktionen effektiv unterdrückt werden können. Dazu wird der iterative DIRECTT-Algorithmus (Direkte Iterative Rekonstruktion Computertomographischer Trajektorien) mit einigen Zyklen diskreter Rekonstruktion eingesetzt. Die Kernfunktionen des Algorithmus', die wiederholte Auswahl und Gewichtung von Elementen einer Zwischenkonstruktion, werden beibehalten. Abgesehen von Sonderfällen der Röntgen- und Neutronentomographie tritt die MW-Restriktion (neben einer Vielzahl anderer) in Standardkonfigurationen der Elektronentomographie auf. Um den MW-Effekt isoliert zu untersuchen und beurteilen zu können, werden hier vollständige experimentelle Datensätze einer bekannten Porenstruktur um einen Sektor beschnitten sowie MW-Rekonstruktionen von Porenmodellen erzeugt. Die Ergebnisse werden mit zurzeit verbreiteten Algorithmen (Gefilterte Rückprojektion (FBP) und ART-Varianten) verglichen. Die Bewertung im Fourierraum zeigt, dass DIRECTT die fehlende Information im MW erfolgreich ergänzt. Zur quantitativen Bewertung der lokalen Rekonstruktionsqualität werden Methoden der räumlichen Statistik eingesetzt.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Computertomographie (CT)
KW - Rekonstruktionsalgorithmus
KW - DIRECTT
KW - Missing Wedge
KW - Statistische Bewertung
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312977
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Poster 18, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-31297
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Hentschel, Manfred P.
A1 - Lange, Axel
A1 - Müller, Bernd R.
T1 - Röntgen-Interface-Radiographie im Dunkelfeld
N2 - Es wird ein Verfahren zur Röntgenabbildung schwach absorbierender Objekte vorgestellt. Als kontrastgebender Effekt wird die Röntgenrefraktion an Ober- und Grenzflächen ausgenutzt. Zur Erzeugung eines sogenannten Dunkelfeldes wird ein schwach gekrümmter Transmissionskristall eingesetzt, der lokal, d.h. in einem kleinen Ausschnitt des Einstrahlquerschnitts, die Bragg-Bedingung erfüllt. Innerhalb dieser Zone erscheinen die durch Refraktion abgelenkten Strahlkomponenten als hell leuchtende Interface-Strukturen. Die Synthese mehrerer Dunkelfeldstreifen ergibt hochaufgelöste 2D Beispiel von biologischen und technischen Mikrostrukturen.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Refraction enhanced imaging (REI)
KW - Radiographie
KW - Dunkelfeldabbildung
KW - Röntgenrefraktion
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-286900
SN - 978-3-940283-49-8
IS - Di.3.C.1
SP - 1
EP - 7
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28690
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Heyn, A.
T1 - Corrosion investigations by using gel-type electrolytes
N2 - Limitations are encountered regarding the electrolyte when studying atmospheric corrosion reactions on materials that form protective layers on their surface or tend to passivate. For example, the reconstruction of a thin wet film, as well as the interpretation of electrochemical measurements in so-called bulk solutions (a "mass" of electrolyte), often proves to be difficult in view of corrosion behavior under atmospheric conditions. A new approach to this problem in corrosion research includes the use of gel-type electrolytes as an alternative to bulk electrolytes. Gel-type electrolytes form a thin wet film on the surface of the material, whereby the naturally formed protective layer is affected similar to atmospheric conditions and can be examined in an almost non-destructive way. Through electrochemical instrumentation specific values such as polarization resistances and corrosion currents can be determined providing information on kinetics of surface layer formation and stability of surface layers formed under the influence of a thin wet film. Thus, new test methods can be developed that supply a better understanding of corrosion processes in specific atmospheres.
In this article different zinc coatings and aluminium alloys were investigated, their naturally formed protective layers were electrochemically characterized and corrosion relevant values were determined by using a gel pad based on polysaccharide. Corrosion relevant values allowed the differentiation of various coating systems and could describe the current protective effect provided by the coating. It is shown that gel-type electrolytes influence protective layers and coatings considerably less than corresponding bulk electrolytes and that an atmospheric wet film is approached by these test conditions. From the results it is evident that gel-type electrolytes represent a viable and promising field in corrosion research.
T2 - 18th Chemnitz Seminar on Materials Engineering – 18. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
KW - Corrosion investigations
KW - Gel-type electrolytes
KW - Zinc coatings
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366680
DO - https://doi.org/10.1088/1757-899X/118/1/011002
VL - 118
SP - 17
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-36668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Unveiling Effects of Biodiesel and Diesel on Environmental Stress Cracking of PE-HD
N2 - The behavior of high‐density polyethylene with respect to resistance against environmental stress cracking (ESC) is usually regarded as an inherent material property being specific for respective types of PE‐HD and tested using standardized methods, conditions, and also standard testing liquids (usually aqueous surfactant solutions). On the other hand, for practical applications the ESC behavior of those polymeric materials, commonly used for pipes or containers, in contact with other liquids (e.g., fuels) is often of relevant interest, but for a reasonable assessment, where consistent benchmark data for a direct comparison are often missing, it is essential to determine the actually prevailing failure mode and classify it related to crack propagation or other mechanisms. Using the well‐established Full Notch Creep Test, which favorably allows for a detailed microscopic fracture surface analysis after failure, the behavior of two typical PE‐HD types for container applications is investigated in biodiesel and diesel and compared to a standard surfactant solution. This enables a clear identification of characteristic features of the interaction of biodiesel and diesel as sorptive fuels in contact with the polymer, revealing the complex interplay of sorption and plasticization as well as ESC inducing effects on PE‐HD, which could be clearly shown for both fuels.
KW - Biodiesel
KW - Confocal laser scanning microscopy (LSM)
KW - Diesel
KW - Full notch creep test (FNCT)
KW - Plasticization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650525
DO - https://doi.org/10.1002/pen.70239
SN - 0032-3888
SP - 1
EP - 16
PB - Wiley
CY - Hoboken (NJ)
AN - OPUS4-65052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Long, Lijia
A1 - Döhler, M.
A1 - Thöns, Sebastian
T1 - Determination of structural and damage detection system influencing parameters on the value of information
N2 - A method to determine the influencing parameters of a structural and damage detection system is proposed based on the value of Information analysis. The value of information analysis utilizes the Bayesian pre-posterior decision theory to quantify the value of damage detection system for the structural integrity management during service life. First, the influencing parameters of the structural system, such as deterioration type and rate are introduced for the performance of the prior probabilistic system model. Then the influencing parameters on the damage detection system performance, including number of sensors, sensor locations, measurement noise, and the Type-I error are investigated. The preposterior probabilistic model is computed utilizing the Bayes’ theorem to update the prior system model with the damage indication information. Finally, the value of damage detection system is quantified as the difference between the maximum utility obtained in pre-posterior and prior analysis based on the decision tree analysis, comprising structural probabilistic models, consequences, as well as benefit and costs analysis associated with and without monitoring. With the developed approach, a case study on a statically determinate Pratt truss bridge girder is carried out to validate the method. The analysis shows that the deterioration rate is the most sensitive parameter on the effect of relative value of information over the whole service life. Furthermore, it shows that more sensors do not necessarily lead to a higher relative value of information; only specific sensor locations near the highest utilized components lead to a high relative value of information; measurement noise and the Type-I error should be controlled and be as small as possible. An optimal sensor employment with highest relative value of information is found. Moreover, it is found that the proposed method can be a powerful tool to develop optimal service life maintenance strategies—before implementation—for similar bridges and to optimize the damage detection system settings and sensor configuration for minimum expected Costs and risks.
KW - Damage detection systems
KW - Value of information
KW - Deteriorating structures
KW - Probability of damage indication
KW - Decision theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508083
DO - https://doi.org/10.1177/1475921719900918
SN - 1475-9217
SN - 1741-3168
VL - 21
IS - 1
SP - 19
EP - 36
PB - Sage Publications
CY - Thousand Oaks, Calif.
AN - OPUS4-50808
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Long, Lijia
A1 - Alcover, I. F.
A1 - Thöns, Sebastian
T1 - Utility analysis for SHM durations and service life extension of welds on steel bridge deck
N2 - Optimization of the duration of Structural Health Monitoring (SHM) campaigns is rarely performed.
This article provides a utility-based solution to posteriorly determine: i) optimal monitoring Durations and ii) the extension of the service life of the welds on a steel bridge deck. The approach is Illustrated with a case study focusing on remaining fatigue life estimation of the welds on the orthotropic steel deck of the Great Belt Bridge, in Denmark. The identification of the optimal monitoring duration and the decision about extending the service life of the welds are modelled by maximizing the expected benefits and minimizing the structural risks. The results are a parametric analysis, mainly on the effect of the target probability, benefit, cost of failure, cost of rehabilitation, cost of monitoring and Discount rate on the posterior utilities of monitoring strategies and the choice of service life considering the risk variability and the costs and benefits models. The results show that the decision on short-term monitoring, i.e., 1 week every six months, is overall the most valued SHM strategy. In addition, it is found that the target probability is the most sensitive parameter affecting the optimal SHM Durations and service life extension of the welds.
KW - Fatigue
KW - Monitoring strategy
KW - Orthotropic steel deck
KW - Structural health monitoring
KW - Utility and decision theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521719
DO - https://doi.org/10.1080/15732479.2020.1866026
SN - 1573-2479
VL - 18
IS - 4
SP - 492
EP - 504
PB - Taylor Francis Online
AN - OPUS4-52171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Long, Lijia
A1 - Anh Mai, Q.
A1 - Morato, P. G.
A1 - Dalsgaard Sorensen, J.
A1 - Thöns, Sebastian
T1 - Information value-based optimization of structural and environmental monitoring for offshore wind turbines support structures
N2 - The use of load and structural performance measurement information is vital for efficient structural integrity management and for the cost of energy production with Offshore Wind Turbines (OWTs). OWTs are dynamically sensitive structures subject to an interaction with a control unit exposed to repeated cyclic wind and wave loads causing deterioration and fatigue. This study focuses on the quantification of the value of structural and environmental information on the integrity management of OWT structures, with the focus on fatigue of welded joints. By utilizing decision analysis, structural reliability methods, measurement data, as well as the cost-benefit models, a Value of Information (VoI) analysis can be performed to quantify the most beneficial measurement strategy. The VoI assessment is demonstrated for the integrity management of a butt welded joint of a monopile support structure for a 3 MW OWT with a hub height of approximately 71m. The conditional value of three-year measured oceanographic information and one-year strain monitoring information is quantified posteriori in conjunction with an inspection and repair planning. This paper provides insights on how much benefits can be achieved through structural and environmental information, with practical relevance on reliability-based maintenance of OWT structures.
KW - Structural health monitoring
KW - Offshore wind turbine
KW - Monopile support structure
KW - Value of information
KW - Weld fatigue
KW - Decision tree
KW - Dynamic Bayesian Network
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514098
DO - https://doi.org/10.1016/j.renene.2020.06.038
VL - 10
IS - 159
SP - 1036
EP - 1046
PB - Elsevier Ltd.
AN - OPUS4-51409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bender, P
A1 - Balceris, C.
A1 - Ludwig, F
A1 - Posth, O
A1 - Bogart, L. K.
A1 - Szczerba, Wojciech
A1 - Castro, A
A1 - Nilsson, L
A1 - Costo, R
A1 - Gavilan, H
A1 - Gonzalez-Alonso, D
A1 - de Pedro, I
A1 - Barquin, L. F.
A1 - Johansson, C
T1 - Distribution functions of magnetic nanoparticles determined by a numerical inversion method
N2 - In the present study, we applied a regularized inversion method to extract the particle size, magnetic moment and relaxation-time distribution of magnetic nanoparticles from small-angle x-ray scattering (SAXS), DC magnetization (DCM) and AC susceptibility (ACS) measurements. For the measurements the particles were colloidally dispersed in water. At first approximation the particles could be assumed to be spherically shaped and homogeneously magnetized single-domain particles. As model functions for the inversion, we used the particle form factor of a sphere (SAXS), the Langevin function (DCM) and the Debye model (ACS). The extracted distributions exhibited features/peaks that could be distinctly attributed to the individually dispersed and non-interacting nanoparticles. Further analysis of these peaks enabled, in combination with a prior characterization of the particle ensemble by electron microscopy and dynamic light scattering, a detailed structural and magnetic characterization of the particles. Additionally, all three extracted distributions featured peaks, which indicated deviations of the scattering (SAXS), magnetization (DCM) or relaxation (ACS) behavior from the one expected for individually dispersed, homogeneously magnetized nanoparticles. These deviations could be mainly attributed to partial agglomeration (SAXS, DCM, ACS), uncorrelated surface spins (DCM) and/or intra-well relaxation processes (ACS). The main advantage of the numerical inversion method is that no ad hoc assumptions regarding the line shape of the extracted distribution functions are required, which enabled the detection of these contributions. We highlighted this by comparing the results with the results obtained by standard model fits, where the functional form of the distributions was a priori assumed to be log-normal shaped.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429373
DO - https://doi.org/10.1088/1367-2630/aa73b4
SN - 1367-2630
VL - 19
SP - 073012, 1
EP - 073012, 19
PB - IOP Publ. Ltd.
AN - OPUS4-42937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirtschin, Nikolaus
A1 - Pretsch, T.
T1 - Programming of one- and two-step stress recovery in a poly(ester urethane)
N2 - This work demonstrates that phase-segregated poly(ester urethane) (PEU) with switching segments of crystallizable poly(1,4-butylene adipate) (PBA) can be programmed to generate two separate stress recovery events upon heating under constant strain conditions. For programming, two elongations are applied at different temperatures, followed by unloading and cooling. During the adjacent heating, two-step stress recovery is triggered. The results indicate that the magnitude of the stress recovery signals corresponds to the recovery of the two deformation stresses in reverse order. As demonstrated by further experiments, twofold stress recovery can be detected as long as the elongation at higher temperature exceeds the strain level of the deformation at lower temperature. Another finding includes that varying the lower deformation temperature enables a control over the stress recovery temperature and thus the implementation of so-called “temperature-memory effects”. Moreover, exerting only one elongation during programming enables a heating-initiated one-step stress recovery close to the deformation temperature. Based on these findings, such polymers may offer new technological opportunities in the fields of active assembly when used as fastening elements and in functional clothing when utilized for compression stockings.
KW - DSC
KW - Mechanical properties
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393585
DO - https://doi.org/10.3390/polym9030098
SN - 2073-4360
VL - 9
IS - 3
SP - Article 98, 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-39358
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smith, A. J.
A1 - Snow, T.
A1 - Terril, N. J.
A1 - Thünemann, Andreas
T1 - The modular small-angle X-ray scattering data correction sequence
N2 - Data correction is probably the least favourite activity amongst users experimenting with small-angle X-ray scattering: if it is not done sufficiently well, this may become evident only during the data analysis stage, necessitating the repetition of the data corrections from scratch. A recommended comprehensive sequence of elementary data correction steps is presented here to alleviate the difficulties associated with data correction, both in the laboratory and at the synchrotron. When applied in the proposed order to the raw signals, the resulting absolute scattering cross section will provide a high degree of accuracy for a very wide range of samples, with its values accompanied by uncertainty estimates. The method can be applied without modification to any pinhole-collimated instruments with photon-counting direct-detection area detectors.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Accuracy
KW - Methodology
KW - Data correction
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-432114
DO - https://doi.org/10.1107/S1600576717015096
SN - 1600-5767
VL - 50
IS - 6
SP - 1800
EP - 1811
PB - International Union of Crystallography
AN - OPUS4-43211
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fuhrmann, A.
A1 - Göstl, R.
A1 - Wendt, R.
A1 - Kötteritzsch, J.
A1 - Hager, M. D.
A1 - Schubert, U. S.
A1 - Brademann-Jock, Kerstin
A1 - Thünemann, Andreas
A1 - Nöchel, U.
A1 - Behl, M.
A1 - Hecht, S.
T1 - Conditional repair by locally switching the thermal healing capability of dynamic covalent polymers with light
N2 - Healable materials could play an important role in reducing the environmental footprint of our
modern technological society through extending the life cycles of consumer products and constructions. However, as most healing processes are carried out by heat alone, the ability to heal damage generally kills the parent material’s thermal and mechanical properties. Here we
present a dynamic covalent polymer network whose thermal healing ability can be switched ‘on’ and ‘off’ on demand by light, thereby providing local control over repair while retaining the advantageous macroscopic properties of static polymer networks. We employ a photoswitchable furan-based crosslinker, which reacts with short and mobile maleimidesubstituted poly(lauryl methacrylate) chains forming strong covalent bonds while simultaneously allowing the reversible, spatiotemporally resolved control over thermally induced de- and re-crosslinking. We reason that our system can be adapted to more complex materials and has the potential to impact applications in responsive coatings, photolithography and microfabrication.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Polymer
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-386689
DO - https://doi.org/10.1038/ncomms13623
SN - 2041-1723
VL - 7
SP - Article 13623, 1
EP - 7
PB - NATURE PUBLISHING GROUP
CY - MACMILLAN BUILDING, 4 CRINAN ST, LONDON N1 9XW, ENGLAND
AN - OPUS4-38668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Kästner, Claudia
A1 - Thünemann, Andreas
T1 - Nanoparticle size distribution quantification: results of a small-angle X-ray scattering inter-laboratory comparison
N2 - This paper presents the first worldwide inter-laboratory comparison of small-angle X-ray scattering (SAXS) for nanoparticle sizing. The measurands in this comparison are the mean particle radius, the width of the size distribution and the particle concentration. The investigated sample consists of dispersed silver nanoparticles, surrounded by a stabilizing polymeric shell of poly(acrylic acid). The silver cores dominate the X-ray scattering pattern, leading to the determination of their radius size distribution using (i) the generalized indirect Fourier transformation method, (ii) classical model fitting using SASfit and (iii) a Monte Carlo fitting approach using McSAS. The application of these three methods to the collected data sets from the various laboratories produces consistent mean number- and volume-weighted core radii of Rn = 2.76 (6) nm and Rv = 3.20 (4) nm, respectively. The corresponding widths of the lognormal radius distribution of the particles were σn = 0.65 (1) nm and σv = 0.71 (1) nm. The particle concentration determined using this method was 3.0 (4) g l−1 or 4.2 (7) × 10−6 mol l−1. These results are affected slightly by the choice of data evaluation procedure, but not by the instruments: the participating laboratories at synchrotron SAXS beamlines, commercial and in-house-designed instruments were all able to provide highly consistent data. This demonstrates that SAXS is a suitable method for revealing particle size distributions in the sub-20 nm region (at minimum), out of reach for most other analytical methods.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Silver nanoparticles
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422800
DO - https://doi.org/10.1107/S160057671701010X
SN - 1600-5767
VL - 50
IS - 5
SP - 1280
EP - 1288
PB - (IUCr) International Union of Crystallography
AN - OPUS4-42280
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liebig, F.
A1 - Thünemann, Andreas
A1 - Koetz, J.
T1 - Ostwald Ripening Growth Mechanism of Gold Nanotriangles in Vesicular Template Phases
N2 - The mechanism of nanotriangle formation in multivesicular vesicles (MMV) is investigated by using time-dependent SAXS measurements in combination with UV−vis spectroscopy, light, and transmission electron microscopy. In the first time period 6.5 nm sized spherical gold nanoparticles are formed inside of the vesicles, which build up soft nanoparticle aggregates. In situ SAXS experiments show a linear increase of the volume and molar mass of nanotriangles in the second time period. The volume growth rate of the triangles is 16.1 nm3/min, and the growth rate in the vertical direction is only 0.02 nm/min. Therefore, flat nanotriangles with a thickness of 7 nm and a diameter of 23 nm are formed. This process can be described by a diffusionlimited Ostwald ripening growth mechanism. TEM micrographs visualize soft coral-like structures with thin nanoplatelets at the periphery of the aggregates, which disaggregate in the third time period into nanotriangles and spherical particles. The 16 times faster growth of nanotriangles in the lateral than that in the vertical direction is related to the adsorption of symmetry breaking components, i.e., AOT and the polyampholyte PalPhBisCarb, on the {111} facets of the gold nanoplatelets in combination with confinement effects of the vesicular template phase.
KW - Gold
KW - Nanoparticle
KW - Small-angle x-ray scattering
KW - SAXS
KW - Kinetics
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379261
DO - https://doi.org/10.1021/acs.langmuir.6b02662
SN - 0743-7463
VL - 32
IS - 42
SP - 10928
EP - 10935
PB - American Chemical Society
AN - OPUS4-37926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szczerba, Wojciech
A1 - Costo, R.
A1 - Veintemillas-Verdaguer, S.
A1 - del Puerto Morales, M.
A1 - Thünemann, Andreas
T1 - SAXS analysis of single- and multi-core iron oxide magnetic nanoparticles
N2 - This article reports on the characterization of four superparamagnetic iron oxide nanoparticles stabilized with dimercaptosuccinic acid, which are suitable candidates for reference materials for magnetic properties. Particles p1 and p2 are single-core particles, while p3 and p4 are multi-core particles. Small-angle X-ray scattering analysis reveals a lognormal type of size distribution for the iron oxide cores of the particles. Their mean radii are 6.9 nm (p1), 10.6 nm (p2), 5.5 nm (p3) and 4.1 nm (p4), with narrow relative distribution widths of 0.08, 0.13, 0.08 and 0.12. The cores are arranged as a clustered network in the form of dense mass fractals with a fractal dimension of 2.9 in the multi-core particles p3 and p4, but the cores are well separated from each other by a protecting organic shell. The radii of gyration of the mass fractals are 48 and 44 nm, and each network contains 117 and 186 primary particles, respectively. The radius distributions of the primary particle were confirmed with transmission electron microscopy. All particles contain purely maghemite, as shown by X-ray absorption fine structure spectroscopy
KW - Superparamagnetic nanoparticles
KW - Iron oxide
KW - Reference materials
KW - SAXS
KW - Small-angle x-ray scattering
KW - XANES
KW - X-ray absorption near-edge structure
KW - X-ray absorption fine structure
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395948
DO - https://doi.org/10.1107/S1600576717002370
SN - 1600-5767
VL - 50
IS - Part 2
SP - 481
EP - 488
PB - (IUCr) International Union of Crystallography
AN - OPUS4-39594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästner, Claudia
A1 - Lichtenstein, Dajana
A1 - Lampen, Alfonso
A1 - Thünemann, Andreas
T1 - Monitoring the fate of small silver nanoparticles during artificial digestion
N2 - The report on the results of an in vitro digestion study of silver nanoparticles in presence and absenceof food. The particles were poly(acrylic acid) stabilized ultra-small silver nanoparticles with a radius of 3.1 nm and a relative size distribution width of 0.2. As food components oil, starch, skimmed milk powderand a mixture thereof were chosen. Aggregation of the particles was quantified with small-angle X-rayscattering in terms of log-normal radii distributions. Complete aggregation of the primary particles wasdetermined in the absence of food. In contrast, the presence of oil and starch initiates a disaggregationin the intestine. Only small aggregates of 6 nm radii and aggregation numbers of 7 were found in thepresence of milk powder. It prevents primary particles from etching in the gastric and intestinal juice.Our results indicate that the silver nanoparticles can pass the digestion process in a nanoscale form butundergo a strong and food-dependent transformation in their state of aggregation.
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404099
DO - https://doi.org/10.1016/j.colsurfa.2016.08.013
SN - 0927-7757
SN - 1873-4359
VL - 526
SP - 76
EP - 81
PB - Elsevier B.V.
AN - OPUS4-40409
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pessanha, Sofia
A1 - Fortes, António
A1 - Lopes, Marta B.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ortega-Feliu, Inés
A1 - Respaldiza, Miguel A.
A1 - Gomez Tubio, Blanca
A1 - Makarova, Anna
A1 - Smirnov, Dmitry
A1 - Kumar, Sourabh
A1 - Mata, António
A1 - Silveira, João
T1 - Multi-technique computational assessment of fluoride uptake in enamel using PIGE, NEXAFS, and Raman spectroscopy
N2 - This study explores F incorporation in enamel via PIGE, NEXAFS, and Raman spectroscopy, integrating experimental/simulated spectra. Machine Learning boosts data interpretation, offering key insights into F delivery for clinical application.
KW - Simulations
KW - Enamel
KW - Fuorine
KW - NEXAFS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631138
DO - https://doi.org/10.1039/D5TB00213C
SN - 2050-750X
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63113
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waurischk, Tina
A1 - Deubener, J.
A1 - Müller, Ralf
T1 - Internal friction and energy dissipation during fracture in silicate glasses
N2 - To obtain a deeper insight into the nature of energy dissipation during fracture, the internal friction of 13 borosilicate, aluminosilicate, soda-lime, and lead-containing glasses, for which inert crack growth data are known, was measured using dynamic mechanical thermal analysis. For asymmetrically bent glass beams, the loss tangent, tan δ, was determined between 0.2 and 50 Hz at temperatures between 273 K and the glass transition temperature, Tg. It was found that the area under the tan δ vs T·Tg−1 curve correlates with the crack growth exponent, n, in the empirical v = v0·KIn relation between crack growth velocity, v, and stress intensity, KI, which indicates that n correlates with the degree of energy dissipation of sub-Tg relaxation phenomena.
KW - Glass
KW - Internal friction
KW - Crack growth
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651371
DO - https://doi.org/10.1063/5.0255432
SN - 0021-9606
VL - 162
IS - 19
SP - 1
EP - 9
PB - AIP Publishing
AN - OPUS4-65137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pan, Z.
A1 - Waurischk, Tina
A1 - Duval, A.
A1 - Müller, Ralf
A1 - Deubener, J.
A1 - Krishnan, N. M. A.
A1 - Wondraczek, K.
A1 - Wondraczek, L.
T1 - Precise Real‐Time Measurement of Liquid Viscosity Using Digital Video Data
N2 - Quantitative knowledge of liquid viscosity is of fundamental importance in many areas of materials synthesis and processing. However, the determination of viscosity often relies on specialized experimental equipment, offline experimentation, or invasive procedures, in particular when required in extreme conditions such as at high temperature, high pressure, and in confined or corrosive environments. Here, this study proposes and validates a fast and simple method that mimics the intuitive perception of liquid flow within a quantitative framework. For this, this study employs digital video observation to derive quantitative values of the shear viscosity of liquids, with high precision and rapid acquisition rates. The technique involves capturing liquid dynamics after minor mechanical stimulation. Processed imaging data are indexed by similarity and referenced to a digital database generated with a finite element model, from which values of viscosity are obtained in line. The approach is tested on water at room temperature and on a high‐temperature glass melt. Covering a viscosity range of four orders of magnitude, both yield convincing agreement with tabulated reference data at low computational cost.
KW - Glass
KW - Liquid Viscosity
KW - Digital Video Data
KW - Finite Element Method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651363
DO - https://doi.org/10.1002/aisy.202500297
SN - 2640-4567
VL - 7
IS - 12
SP - 1
EP - 12
PB - Wiley VHC-Verlag
AN - OPUS4-65136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Leidigkeit, Carolin
A1 - Shokr, Mohammad
A1 - Tosson, Amir
A1 - Cakir, Cafer Tufan
A1 - Radtke, Martin
A1 - Pietsch, Ullrich
A1 - Christ, Hans-Jürgen
T1 - Using Energy-Dispersive Laue Diffraction to Study Dislocation Arrangements in Materials Showing Wavy and Planar Slip Behavior
N2 - The present work shows an approach to monitor the evolution of the dislocation arrangement of a metallic material caused by cyclic plastic strain using white X-ray radiation in combination with an energy-dispersive detector. The method is demonstrated by single-shot experiments performed on polycrystalline nickel and α-brass, representing the pure wavy and the pure planar dislocation slip behavior. To correlate the resulting diffraction patterns with various dislocation arrangements of both metals, fatigue tests were carried out up to certain numbers of cycles and at predetermined plastic strain amplitudes. The differences in dislocation microstructure and internal stress distributions give rise to an appreciable change in the peak shape of Laue reflections, leading to unique characteristics in the respective diffraction patterns. Nickel reflections are elongated due to the high amount of cell structures leading to bending and misorientation of the lattice, whereas the present stacking faults in α-brass result in powder-like diffraction.
KW - Slip behavior
KW - Energy-Dispersive
KW - Laue Diffraction
KW - Dislocation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637964
DO - https://doi.org/10.1111/ffe.14535
SN - 1460-2695
VL - 48
IS - 3
SP - 1341
EP - 1351
PB - Wiley
AN - OPUS4-63796
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Bernal, S. A.
T1 - RILEM TC CUC: Carbon dioxide uptake by concrete during and after service life – Opening Letter
N2 - The ability of cement to chemically bind CO2 in a carbonation reaction enables the material to act as a carbon sink, which could partly account for offsetting the CO2 emissions associated with cement production. In response to the many open questions in this context, the RILEM Technical Committee CUC was created in May 2024. The focus of the TC will be to facilitate discussions regarding the current approaches to estimate the CO2 uptake by cementitious materials (concrete and other construction products) during and after service life. This Opening Letter presents aspects of the motivation to establish the TC, a brief overview of the state of the art in the field, the scheduled work programme, and the anticipated impact of the TC outputs. Though it is not intended to be an exhaustive discussion of the challenges to be addressed, from what is summarized in this letter, it is clear that work is required to base estimates of CO2 uptake by cementitious materials on a data set that is as extensive, accurate and forward-looking as possible. It is anticipated that the inclusion of interdisciplinary perspectives and data from academia and industry will enable progress in the field.
KW - Cement
KW - Concrete
KW - Recarbonation
KW - Carbon dioxide uptake
KW - Carbonation rate
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623724
DO - https://doi.org/10.21809/rilemtechlett.2024.208
SN - 2518-0231
VL - 9
SP - 61
EP - 67
PB - RILEM
AN - OPUS4-62372
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gluth, Gregor
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Dauerhaftigkeit von Betonen auf Basis klimafreundlicher Bindemittel
N2 - Aus Gründen des Klimaschutzes werden in den kommenden Jahren mehr Zemente mit verringertem Klinkerfaktor und alternative Bindemittel (klimafreundliche Bindemittel) zum Einsatz kommen. Für ihre sichere und zuverlässige Verwendung ist ein umfangreiches Verständnis der Einflüsse auf die Dauerhaftigkeit der aus ihnen hergestellten Betone notwendig. Der vorliegende Beitrag gibt einen kurzen Überblick über einige jüngere Entwicklungen und Forschungsergebnisse auf dem Gebiet. Der Fokus liegt auf Ergebnissen der Arbeiten von Technischen Komitees der RILEM sowie der EFC und eigenen Forschungsergebnissen.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Klimafreundliche Bindemittel
KW - Betone
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612872
SN - 978-3-9818564-7-7
SP - 22
EP - 29
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61287
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sittner, Jonathan
A1 - Hoffmann, T.
A1 - Bertmer, M.
A1 - Neubert, M.
A1 - Schuster, T.
A1 - Gluth, Gregor
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Optimizing calcination methods towards a more sustainable production of calcined clays
N2 - Calcined clays are emerging as sustainable alternatives for cement production due to their potential to reduce carbon footprint and energy consumption. This study investigates the calcination of low-grade kaolinitic clays, using rotary kiln and fluidized bed. The calcined clays from the rotary kiln showed enhanced performance in the cement paste. The fluidized bed method demonstrated the potential for significant energy savings, achieving near-complete dehydroxylation with just 30 minutes of calcination. These findings highlight the promise of fluidized bed calcination for efficient clay activation, though further optimization is needed.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Calcination methods
KW - Optimizing
KW - Blended cement pastes
KW - XRD results
KW - Thermogravimetric analysis (TGA)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612891
SN - 978-3-9818564-7-7
SP - 37
EP - 45
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gluth, Gregor
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Alkalisch aktivierte Bindemittel mit hohem Säurewiderstand für die Kanalsanierung
N2 - Die biogene Schwefelsäurekorrosion (BSK) von Betonbauteilen in Abwassersystemen verursacht weltweit hohen Reparaturbedarf. Um zukünftigen Reparaturbedarf zu minimieren, werden für Neubau- und Sanierungsmaßnahmen z. T. Materialien mit besonders hohem Widerstand gegen BSK benötigt. Der vorliegende Beitrag beschreibt Forschungen zu alkalisch aktivierten Bindemitteln, die bei geeigneter Formulierung einen hohen Widerstand gegen BSK bzw. Säureangriff aufweisen. Zusätzlich werden jüngste Fortschritte bei der Bewertung von Methoden zur Prüfung des Widerstands gegen BSK dargestellt.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Säurewiderstand
KW - Betonbauteile
KW - Abwassersystemen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613141
SN - 978-3-9818564-7-7
SP - 90
EP - 93
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61314
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Nikoonasab, Ali
A1 - Müller, Thoralf
A1 - Licht, M.
A1 - Raupach, M.
A1 - Gluth, Gregor
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Sulfides in the pore solutions of GGBFS-containing concretes - Influence on the corrosion of reinforcing steel
N2 - Steel corrosion in sulfide-containing solutions is a challenge in various environments, such as reinforced concrete structures. In concrete, sulfides are introduced by ground granulated blast-furnace slag (GGBFS), used in standard cements and alkali-activated materials (AAMs), affecting steel corrosion. This study examined steel in synthetic GGBFS-containing cement pore solutions using electrochemical techniques. Compared to Portland cement solutions, steel in sulfide-containing solutions exhibits lower open circuit potentials and polarisation resistances. Thus, Portland cement concrete corrosion assessment standards are unsuitable for GGBFScontaining concrete.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - Corrosion
KW - Reinforcing steel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612963
SN - 978-3-9818564-7-7
SP - 55
EP - 59
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shafiey, H.
A1 - Gogol-Döring, A.
A1 - McMahon, Dino Peter
A1 - Doublet, V.
A1 - Disayathanoowat, T.
A1 - Paxton, R. J.
T1 - A new variant of slow bee paralysis virus revealed by transcriptome analysis
N2 - Using NGS data from an RNA-seq library, we reveal a novel variant of slow bee paralysis virus (SBPV) in a pooled sample of adult honey bees (Apis mellifera) collected in southwest Germany. We provide its sequence (NCBI Accession No. PP100271) and demonstrate that it is infective for adult honey bees by feeding.
KW - SBPV
KW - Apis mellifera
KW - +ss RNA virus
KW - Iflaviridae
KW - Transmission
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645577
DO - https://doi.org/10.1080/00218839.2024.2425912
VL - 64
IS - 1
SP - 56
EP - 59
PB - Taylor & Francis
AN - OPUS4-64557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Varadarajan, A.
A1 - Allan, R.
A1 - Valentin, J.
A1 - Castañeda Ocampo, O.
A1 - Somerville, V.
A1 - Buhmann, M.
A1 - West, J.
A1 - Skipp, Paul
A1 - van der Mei, H.
A1 - Ren, Q.
A1 - Schreiber, Frank
A1 - Webb, J.
A1 - Pietsch, Franziska
A1 - Ahrens, C.
T1 - An integrated model system to gain mechanistic insights into biofilm-associated antimicrobial resistance in Pseudomonas aeruginosa MPAO1
N2 - Pseudomonas aeruginosa MPAO1 is the parental strain of the widely utilized transposon mutant collection for this important clinical pathogen. Here, we validate a model system to identify genes involved in biofilm growth and biofilm-associated antibiotic resistance. Our model employs a genomics-driven workflow to assemble the complete MPAO1 genome, identify unique and conserved genes by comparative genomics with the PAO1 reference strain and genes missed within existing assemblies by proteogenomics. Among over 200 unique MPAO1 genes, we identified six general essential genes that were overlooked when mapping public Tn-seq data sets against PAO1, including an antitoxin. Genomic data were integrated with phenotypic data from an experimental workflow using a user-friendly, soft lithography-based microfluidic flow chamber for biofilm growth and a screen with the Tn-mutant library in microtiter plates. The screen identified hitherto unknown genes involved in biofilm growth and antibiotic resistance. Experiments conducted with the flow chamber across three laboratories delivered reproducible data on P. aeruginosa biofilms and validated the function of both known genes and genes identified in the Tn-mutant screens. Differential Protein abundance data from planktonic cells versus biofilm confirmed the upregulation of candidates known to affect biofilm formation, of structural and secreted proteins of type VI secretion systems, and provided proteogenomic evidence for some missed MPAO1 genes. This integrated, broadly applicable model promises to improve the mechanistic understanding of biofilm formation, antimicrobial tolerance, and resistance evolution in biofilms.
KW - Biofilms
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515108
DO - https://doi.org/10.1038/s41522-020-00154-8
VL - 6
IS - 1
SP - Article number: 46
PB - Springer Nature
CY - Singapore
AN - OPUS4-51510
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupke, Johannes
A1 - Brombach, Julian
A1 - Fang, Yuwen
A1 - Wolf, Silver A.
A1 - Thrukonda, Lakshmipriya
A1 - Ghazisaeedi, Fereshteh
A1 - Kuropka, Benno
A1 - Hanke, Dennis
A1 - Semmler, Torsten
A1 - Nordholt, Niclas
A1 - Schreiber, Frank
A1 - Tedin, Karsten
A1 - Lübke-Becker, Antina
A1 - Steiner, Ulrich K.
A1 - Fulde, Marcus
T1 - Heteroresistance in Enterobacter cloacae complex caused by variation in transient gene amplification events
N2 - Heteroresistance (HR) in bacteria describes a subpopulational phenomenon of antibiotic resistant cells of a generally susceptible population. Here, we investigated the molecular mechanisms and phenotypic characteristics underlying HR to ceftazidime (CAZ) in a clinical Enterobacter cloacae complex strain (ECC). We identified a plasmid-borne gene duplication-amplification (GDA) event of a region harbouring an ampC gene encoding a β-lactamase bla DHA-1 as the key determinant of HR. Individual colonies exhibited variations in the copy number of the genes resulting in resistance level variation which correlated with growth onset (lag times) and growth rates in the presence of CAZ. GDA copy number heterogeneity occurred within single resistant colonies, demonstrating heterogeneity of GDA on the single-cell level. The interdependence between GDA, lag time and antibiotic treatment and the strong plasticity underlying HR underlines the high risk for misdetection of antimicrobial HR and subsequent treatment failure.
KW - Antimicrobial surfaces
KW - Biocides
KW - Antimicrobial resistance
KW - Standardization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627057
DO - https://doi.org/10.1038/s44259-025-00082-7
VL - 3
IS - 1
SP - 1
EP - 14
PB - Springer
AN - OPUS4-62705
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srivastava, Priyanka
A1 - Tavernaro, Isabella
A1 - Scholtz, Lena
A1 - Genger, C.
A1 - Welker, P.
A1 - Schreiber, Frank
A1 - Meyer, Klas
A1 - Resch-Genger, Ute
T1 - Dual color pH probes made from silica and polystyrene nanoparticles and their performance in cell studies
N2 - Ratiometric green–red fluorescent nanosensors for fluorometrically monitoring pH in the acidic range were designed from 80 nm-sized polystyrene (PS) and silica (SiO2) nanoparticles (NPs), red emissive reference dyes, and a green emissive naphthalimide pH probe, analytically and spectroscopically characterized, and compared regarding their sensing performance in aqueous dispersion and in cellular uptake studies. Preparation of these optical probes, which are excitable by 405 nm laser or LED light sources, involved the encapsulation of the pH-inert red-fuorescent dye Nile Red (NR) in the core of self-made carboxylated PSNPs by a simple swelling procedure and the fabrication of rhodamine B (RhB)-stained SiO2-NPs from a silane derivative of pH-insensitive RhB. Subsequently, the custom-made naphthalimide pH probe, that utilizes a protonation-controlled photoinduced electron transfer process, was covalently attached to the carboxylic acid groups at the surface of both types of NPs. Fluorescence microscopy studies with the molecular and nanoscale optical probes and A549 lung cancer cells confirmed the cellular uptake of all probes and their penetration into acidic cell compartments, i.e., the lysosomes, indicated by the switching ON of the green naphthalimide fluorescence. This underlines their suitability for intracellular pH sensing, with the SiO2-based nanosensor revealing the best performance regarding uptake speed and stability.
KW - Sensors
KW - Silica and polystyrene nanoparticles
KW - pH probe
KW - Fluorescence spectroscopy
KW - Cell studies
KW - Dye
KW - Particle synthesis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569198
DO - https://doi.org/10.1038/s41598-023-28203-0
SN - 2045-2322
VL - 13
IS - 1
SP - 1321
EP - 1336
PB - Nature
CY - London
AN - OPUS4-56919
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keshmiri, Hamid
A1 - Armin, F.
A1 - Elsayad, K.
A1 - Schreiber, Frank
A1 - Moreno, M.
T1 - Leaky and waveguide modes in biperiodic holograms
N2 - This study details a theoretical analysis of leaky and waveguide modes in biperiodic all-dielectric holograms. By tuning diffraction orders and subsequently confining local density of optical states at two distinct resonance wavelengths, we present a new class of highly sensitive refractive index biosensing platforms that are capable of resolving 35.5 to 41.3 nm/RIU of spectral shift for two separate biological analytes.
KW - Antimicrobial resistance
KW - Bacteria
KW - Photonics
KW - Diffractive gratings
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527632
DO - https://doi.org/10.1038/s41598-021-89971-1
SN - 2045-2322 (online)
VL - 11
IS - 1
SP - 10991
PB - Springer Nature
AN - OPUS4-52763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nordholt, Niclas
A1 - Sobisch, Lydia-Yasmin
A1 - Gödt, Annett
A1 - Lewerenz, Dominique
A1 - Schreiber, Frank
T1 - Heterogeneous survival upon disinfection underlies evolution of increased tolerance
N2 - Disinfection is important to limit the spread of infections, but failure of disinfection may foster the evolution of antimicrobial resistance in bacteria. Persisters are phenotypically tolerant subpopulations that survive toxic stress longer than susceptible cells, leading to failure in treatments with antimicrobials and facilitating resistance evolution. To date, little is known about persistence in the context of disinfectants. The aim of this study was to investigate the influence of persisters on disinfection and to determine the consequences of disinfectant persistence for the evolution of increased tolerance to disinfectants. Disinfection kinetics with high temporal resolution were recorded for Escherichia coli exposed to the following six disinfectants: hydrogen peroxide (H2O2), glutaraldehyde (GTA), chlorhexidine (CHX), benzalkonium chloride (BAC), didecyldimethylammonium chloride (DDAC), and isopropanol (ISO). A mathematical model was used to infer the presence of persisters from the time–kill data. Time–kill kinetics for BAC, DDAC, and ISO were indicative of persisters, whereas no or weak evidence was found for H2O2, GTA, and CHX. When subjected to comparative experimental evolution under recurring disinfection, E. coli evolved increased tolerance to substances for which persisters were predicted (BAC and ISO), whereas adaptation failed for substances in which no persisters were predicted (GTA and CHX), causing extinction of exposed populations. Our findings have implications for the risk of disinfection failure, highlighting a potential link between persistence to disinfectants and the ability to evolve disinfectant survival mechanisms.
IMPORTANCE: Disinfection is key to control the spread of infections. But the application of disinfectants bears the risk to promote the evolution of reduced susceptibility to antimicrobials if bacteria survive the treatment. The ability of individual bacteria to survive disinfection can display considerable heterogeneity within isogenic populations and may be facilitated by tolerant persister subpopulations. Using time–kill kinetics and interpreting the data within a mathematical framework, we quantify heterogeneity and persistence in Escherichia coli when exposed to six different disinfectants. We find that the level of persistence, and with this the risk for disinfection failure, depends on the disinfectant. Importantly, evolution experiments under recurrent disinfection provide evidence that links the presence of persisters to the ability to evolve reduced susceptibility to disinfectants. This study emphasizes the impact of heterogeneity within bacterial populations on disinfection outcomes and the potential consequences for the evolution of antimicrobial resistances.
KW - Antimicrobial resistance
KW - Bacteria
KW - Standardization
KW - Biocides
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615566
DO - https://doi.org/10.1128/spectrum.03276-22
SN - 2165-0497
VL - 12
IS - 12
SP - 1
EP - 11
PB - American Society for Microbiology
CY - Birmingham, Ala.
AN - OPUS4-61556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pietsch, Franziska
A1 - O'Neill, A. J.
A1 - Ivask, A.
A1 - Jenssen, H.
A1 - Inkinen, J.
A1 - Kahru, A.
A1 - Ahonen, M.
A1 - Schreiber, Frank
T1 - Selection of resistance by antimicrobial coatings in the healthcare setting
N2 - Antimicrobial touch surfaces have been introduced in healthcare settings with the aim of supporting existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which may drive the evolution and spread of antimicrobial resistance. This review highlights studies that indicate risks associated with resistance on antimicrobial surfaces by different processes, including evolution by de-novo mutation and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed on to antimicrobial surfaces. The review focuses on antimicrobial surfaces made of copper, silver and antimicrobial peptides because of the practical application of copper and silver, and the promising characteristics of antimicrobial peptides. The available data point to a potential for resistance selection and a subsequent increase in resistant strains via cross-resistance and co-resistance conferred by metal and antibiotic resistance traits. However, translational studies describing the development of resistance to antimicrobial touch surfaces in healthcare-related environments are rare, and will be needed to assess whether and how antimicrobial surfaces lead to resistance selection in These settings. Such studies will need to consider numerous variables, including the antimicrobial concentrations present in coatings, the occurrence of biofilms on surfaces, and the humidity relevant to dry-surface environments. On-site tests on the efficacy of antimicrobial Coatings should routinely evaluate the risk of selection associated with their use.
KW - Antimicrobial resistance
KW - Antimicrobial coating
KW - Touch surfaces
KW - Healthcare
KW - Infections
KW - COST action CA15114 AMICI
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510926
DO - https://doi.org/10.1016/j.jhin.2020.06.006
SN - 0195-6701
VL - 106
IS - 1
SP - 115
EP - 125
PB - Elsevier Ltd
AN - OPUS4-51092
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marchant, H. K.
A1 - Tegetmeyer, H. E.
A1 - Ahmerkamp, S.
A1 - Holtappels, M.
A1 - Lavik, G.
A1 - Graf, J.
A1 - Schreiber, Frank
A1 - Mussmann, M.
A1 - Strous, M.
A1 - Kuypers, M. M. M.
T1 - Metabolic specialization of denitrifiers in permeable sediments controls N2O emissions
N2 - Coastal oceans receive large amounts of anthropogenic fixed nitrogen (N), most of which is denitrified in the sediment before reaching the open ocean. Sandy sediments, which are common in coastal regions, seem to play an important role in catalysing this N‐loss. Permeable sediments are characterized by advective porewater transport, which supplies high fluxes of organic matter into the sediment, but also leads to fluctuations in oxygen and nitrate concentrations. Little is known about how the denitrifying communities in these sediments are adapted to such fluctuations. Our combined results indicate that denitrification in eutrophied sandy sediments from the world's largest tidal flat system, the Wadden Sea, is carried out by different groups of microorganisms. This segregation leads to the formation of N2O which is advectively transported to the overlying waters and thereby emitted to the atmosphere. At the same time, the production of N2O within the sediment supports a subset of Flavobacteriia which appear to be specialized on N2O reduction. If the mechanisms shown here are active in other coastal zones, then denitrification in eutrophied sandy sediments may substantially contribute to current marine N2O emissions.
KW - Nitrous oxide
KW - Denitrification
KW - Cross-feeding
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-463061
UR - https://onlinelibrary.wiley.com/doi/full/10.1111/1462-2920.14385
DO - https://doi.org/10.1111/1462-2920.14385
SN - 1462-2920
SN - 1462-2912
VL - 20
IS - 12
SP - 4486
EP - 4502
PB - John Wiley & Sons Ltd
AN - OPUS4-46306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nordholt, Niclas
A1 - Kanaris, Orestis
A1 - Schmidt, Selina
A1 - Schreiber, Frank
T1 - Persistence against benzalkonium chloride promotes rapid evolution of tolerance during periodic disinfection
N2 - Biocides used as disinfectants are important to prevent the transmission of pathogens, especially during the current antibiotic resistance crisis. This crisis is exacerbated by phenotypically tolerant persister subpopulations that can survive transient antibiotic Treatment and facilitate resistance evolution. Here, we show that E. coli displays persistence against a widely used disinfectant, benzalkonium chloride (BAC). Periodic, persister-mediated failure of disinfection rapidly selects for BAC tolerance, which is associated with reduced cell Surface charge and mutations in the lpxM locus, encoding an enzyme for lipid A biosynthesis.
Moreover, the fitness cost incurred by BAC tolerance turns into a fitness benefit in the presence of antibiotics, suggesting a selective advantage of BAC-tolerant mutants in antibiotic environments. Our findings highlight the links between persistence to disinfectants and resistance evolution to antimicrobials.
KW - Persistence
KW - Biocides
KW - Evolution
KW - Cross-resistance
KW - Biocide tolerance
KW - Disinfection
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538532
DO - https://doi.org/10.1038/s41467-021-27019-8
SN - 2041-1723
VL - 12
IS - 1
SP - 6792
PB - Springer
AN - OPUS4-53853
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vareschi, Silvia
A1 - Jaut, Valerie
A1 - Vijay, Srinivasan
A1 - Allen, Rosalind J.
A1 - Schreiber, Frank
T1 - Antimicrobial efflux and biofilms: an interplay leading to emergent resistance evolution
N2 - The biofilm mode of growth and drug efflux are both important factors that impede the treatment of bacterial infections with antimicrobials. Decades of work have uncovered the mechanisms involved in both efflux and biofilm-mediated antimicrobial tolerance, but links between these phenomena have only recently been discovered. Novel findings show how efflux impacts global cellular physiology and antibiotic tolerance, underpinned by phenotypic heterogeneity. In addition efflux can mediate cell-to-cell interactions, relevant in biofilms, via mechanisms including efflux of signaling molecules and metabolites, signaling using pump components and the establishment of local antibiotic gradients via pumping. These recent findings suggest that biofilm antibiotic tolerance and efflux are closely coupled, with synergistic effects leading to the evolution of antimicrobial resistance in the biofilm environment.
KW - Evolution
KW - Efflux
KW - Antibiotics
KW - Biofilms
KW - Antimicrobial resistance
KW - Phenotypic heterogeneity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632799
DO - https://doi.org/10.1016/j.tim.2025.04.012
SN - 0966-842X
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-63279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lee, Mihyun
A1 - Wiesli, Luzia
A1 - Schreiber, Frank
A1 - Ivask, Angela Ivask
A1 - Ren, Qun
T1 - Quantitative Assessment of Microbial Transmission onto Environmental Surfaces Using Thermoresponsive Gelatin Hydrogels as a Finger Mimetic under In Situ-Mimicking Conditions
N2 - Surface-mediated transmission of pathogens plays a key role in healthcare-associated infections. However, proper techniques for its quantitative analysis are lacking, making it challenging to develop novel antimicrobial and anti-fouling surfaces to reduce pathogen spread via environmental surfaces. This study demonstrates a gelatin hydrogel-based touch transfer test, the HydroTouch test, to evaluate pathogen transmission on high-touch surfaces under semi-dry conditions. The HydroTouch test employs gelatin as a finger mimetic, facilitating testing with pathogenic bacteria under controlled conditions. The thermoresponsive sol–gel transition of gelatin allows easy recovery and quantification of bacteria before and after testing. The HydroTouch test demonstrates that methicillin-resistant Staphylococcus aureus has a high transmission efficiency of ≈16% onto stainless steel, compared to <3% for Escherichia coli or Pseudomonas aeruginosa. Polyurethane surfaces exhibit strong resistance to bacterial contamination with a transmission efficiency of ≈0.6%, while polytetrafluoroethylene shows a transmission efficiency approximately four times higher than polyurethane. Additionally, quaternary ammonium-based antimicrobial coatings reduce the transmission efficiency of live bacteria on stainless steel to ≈4% of the original level. The HydroTouch test provides a reliable method for assessing pathogen transmission on various surfaces under semi-dry settings, supporting the development of effective antimicrobial, anti-transmission coatings to reduce healthcare-associated infections.
KW - Antimicrobial surfaces
KW - Biocides
KW - Antimicrobial resistance
KW - Standardization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624566
DO - https://doi.org/10.1002/adhm.202403790
SN - 2192-2659
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-62456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kanaris, Orestis
A1 - Schreiber, Frank
T1 - Refuse in order to resist: metabolic bottlenecks reduce antibiotic susceptibility
N2 - The growth of pathogenic bacteria in the host is a prerequisite for infectious diseases. Antibiotic drugs are used to impair bacterial growth and thereby treat infections. In turn, growth of bacteria is underpinned by their primary metabolism. Thus,it has long been recognized that the activity of antibiotics is determined by the metabolic state of cells. However, only recently researchers have begun to systematically interrogate the links between metabolism and resistance. In their recent study, Lubrano and colleagues (Lubranoet al, 2025) apply an elegant CRISPR-based approach to the model bacterium Escherichia coli to systematically screen the effect of 15,120 mutations in genes that encode for 346 proteins which are required for growth of E. coli (also referred to as ‘essential proteins’). The authors identified a multitude of mutations that reduce the susceptibility against two antibiotics related to two very distinct chemical classes; the β-lactam antibiotic carbenicillin and the aminoglycoside gentamicin. Strikingly, the majority of the identified mutations are directly linked to primary metabolism. The work highlights the importance of metabolism in order to understand antibiotic resistance mechanisms and the ecology and evolution of antibiotic resistance. In addition, the work provides leads to design metabolism-based intervention strategies to mitigate antibiotic resistance.
KW - Metabolism
KW - Antibiotic resistance
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626608
DO - https://doi.org/10.1038/s44320-025-00089-2
SN - 1744-4292
VL - 21
IS - 3
SP - 211
EP - 213
AN - OPUS4-62660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nordholt, Niclas
A1 - O'Hara, Kate
A1 - Resch-Genger, Ute
A1 - Blaskovich, M.
A1 - Rühle, Bastian
A1 - Schreiber, Frank
T1 - A fluorescently labelled quaternary ammonium compound (NBD-DDA) to study resistance mechanisms in bacteria
N2 - Quaternary ammonium compounds (QACs) are widely used as active agents in disinfectants, antiseptics, and preservatives. Despite being in use since the 1940s, there remain multiple open questions regarding their detailed mode-of-action and the mechanisms, including phenotypic heterogeneity, that can make bacteria less susceptible to QACs. To facilitate studies on resistance mechanisms towards QACs, we synthesized a fluorescent quaternary ammonium compound, namely N-dodecyl-N,N-dimethyl-[2-[(4-nitro-2,1,3-benzoxadiazol-7-yl)amino]ethyl]azanium-iodide (NBD-DDA). NBD-DDA is readily detected by flow cytometry and fluorescence microscopy with standard GFP/FITC-settings, making it suitable for molecular and single-cell studies. As a proof-of-concept, NBD-DDA was then used to investigate resistance mechanisms which can be heterogeneous among individual bacterial cells. Our results reveal that the antimicrobial activity of NBD-DDA against Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa is comparable to that of benzalkonium chloride (BAC), a widely used QAC, and benzyl-dimethyl-dodecylammonium chloride (BAC12), a mono-constituent BAC with alkyl-chain length of 12 and high structural similarity to NBD-DDA. Characteristic time-kill kinetics and increased tolerance of a BAC tolerant E. coli strain against NBD-DDA suggest that the mode of action of NBD-DDA is similar to that of BAC. As revealed by confocal laser scanning microscopy (CLSM), NBD-DDA is preferentially localized to the cell envelope of E. coli, which is a primary target of BAC and other QACs. Leveraging these findings and NBD-DDA‘s fluorescent properties, we show that reduced cellular accumulation is responsible for the evolved BAC tolerance in the BAC tolerant E. coli strain and that NBD-DDA is subject to efflux mediated by TolC. Overall, NBD-DDA’s antimicrobial activity, its fluorescent properties, and its ease of detection render it a powerful tool to study resistance mechanisms of QACs in bacteria and highlight its potential to gain detailed insights into its mode-of-action.
KW - Antimicrobial resistance
KW - Bacteria
KW - Disinfection
KW - Biocides
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563811
DO - https://doi.org/10.3389/fmicb.2022.1023326
SN - 1664-302X
IS - 13
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-56381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valentin, J.
A1 - Straub, H.
A1 - Pietsch, Franziska
A1 - Lemare, M.
A1 - Ahrens, C.
A1 - Schreiber, Frank
A1 - Webb, J.
A1 - van der Mei, H.
A1 - Ren, Q.
T1 - Role of the flagellar hook in the structural development and antibiotic tolerance of Pseudomonas aeruginosa biofilms
N2 - Pseudomonas aeruginosa biofilms exhibit an intrinsic resistance to antibiotics and constitute a considerable clinical threat. In cystic fibrosis, a common feature of biofilms formed by P. aeruginosa in the airway is the occurrence of mutants deficient in flagellar motility. This study investigates the impact of flagellum deletion on the structure and antibiotic tolerance of P. aeruginosa biofilms, and highlights a role for the flagellum in adaptation and cell survival during biofilm development. Mutations in the flagellar hook protein FlgE influence greatly P. aeruginosa biofilm structuring and antibiotic tolerance. Phenotypic analysis of the flgE knockout mutant compared to the wild type (WT) reveal increased fitness under planktonic conditions, reduced initial adhesion but enhanced formation of microcolony aggregates in a microfluidic environment, and decreased expression of genes involved in exopolysaccharide formation. Biofilm cells of the flgE knock-out mutant display enhanced tolerance towards multiple antibiotics, whereas its planktonic cells show similar resistance to the WT. Confocal microscopy of biofilms demonstrates that gentamicin does not affect the viability of cells located in the inner part of the flgE knock-out mutant biofilms due to reduced penetration. These findings suggest that deficiency in flagellar proteins like FlgE in biofilms and in cystic fibrosis infections represent phenotypic and evolutionary adaptations that alter the structure of P. aeruginosa biofilms conferring increased antibiotic tolerance.
KW - Antimicrobial resistance
KW - Bacteria
KW - Biofilms
KW - Biocides
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541113
DO - https://doi.org/10.1038/s41396-021-01157-9
SN - 1751-7370
VL - 16
IS - 4
SP - 1176
EP - 1186
PB - Springer Nature
AN - OPUS4-54111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Franziska, Pietsch
A1 - Nordholt, Niclas
A1 - Heidrich, Gabriele
A1 - Schreiber, Frank
T1 - Prevalent Synergy and Antagonism Among Antibiotics and Biocides in Pseudomonas aeruginosa
N2 - Antimicrobials can exert specific physiological effects when used in combination that are different from those when applied alone. While combination effects have been extensively mapped for antibiotic-antibiotic combinations, the combination effects of antibiotics with antimicrobials used as biocides or antiseptics have not been systematically investigated. Here, we investigated the effects of combinations of antibiotics (meropenem, gentamicin, and ciprofloxacin) and substances used as biocides or antiseptics [octenidine, benzalkonium chloride, cetrimonium bromide, chlorhexidine, Povidone-iodine, silver nitrate (AgNO3), and Ag-nanoparticles] on the planktonic growth rate of Pseudomonas aeruginosa. Combination effects were investigated in growth experiments in microtiter plates at different concentrations and the Bliss interaction scores were calculated. Among the 21 screened combinations, we find prevalent combination effects with synergy occurring six times and antagonism occurring 10 times. The effects are specific to the antibiotic-biocide combination with meropenem showing a tendency for antagonism with biocides (6 of 7), while gentamicin has a tendency for synergy (5 of 7). In conclusion, antibiotics and biocides or antiseptics exert physiological combination effects on the pathogen P. aeruginosa. These effects have consequences for the efficacy of both types of substances and potentially for the selection of antimicrobial resistant strains in clinical applications with combined exposure (e.g., wound care and coated biomaterials).
KW - Synergy
KW - Antagonism
KW - Suppression
KW - Biocides
KW - Antibiotics
KW - Pseudomonas aeruginosa
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520845
DO - https://doi.org/10.3389/fmicb.2020.615618
VL - 11
SP - Article 615618
PB - Frontiers
CY - Lausanne
AN - OPUS4-52084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Valentin, Jules D. P.
A1 - Altenried, Stefanie
A1 - Varadarajan, Adithi R.
A1 - Ahrens, Christian H.
A1 - Schreiber, Frank
A1 - Webb, Jeremy S.
A1 - van der Mei, Henny C.
A1 - Ren, Qun
T1 - Identification of Potential Antimicrobial Targets of Pseudomonas aeruginosa Biofilms through a Novel Screening Approach
N2 - Pseudomonas aeruginosa is an opportunistic pathogen of considerable medical importance, owing to its pronounced antibiotic tolerance and association with cystic fibrosis and other life-threatening diseases. The aim of this study was to highlight the genes responsible for P. aeruginosa biofilm tolerance to antibiotics and thereby identify potential new targets for the development of drugs against biofilm-related infections. By developing a novel screening approach and utilizing a public P. aeruginosa transposon insertion library, several biofilm-relevant genes were identified. The Pf phage gene (PA0720) and flagellin gene (fliC) conferred biofilm-specific tolerance to gentamicin. Compared with the reference biofilms, the biofilms formed by PA0720 and fliC mutants were completely eliminated with a 4-fold-lower gentamicin concentration. Furthermore, the mreC, pprB, coxC, and PA3785 genes were demonstrated to play major roles in enhancing biofilm tolerance to gentamicin. The analysis of biofilm-relevant genes performed in this study provides important novel insights into the understanding of P. aeruginosa antibiotic tolerance, which will facilitate the detection of antibiotic resistance and the development of antibiofilm strategies against P. aeruginosa.
KW - Antimicrobial resistance
KW - Bacteria
KW - Biofilms
KW - Pseudomonas aeruginosa
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570205
DO - https://doi.org/10.1128/spectrum.03099-22
SP - 1
EP - 5
PB - ASM Journals
AN - OPUS4-57020
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chacón, Luz
A1 - Kuropka, B.
A1 - González-Tortuero, E.
A1 - Schreiber, Frank
A1 - Rojas-Jiménez, K.
A1 - Rodríguez-Rojas, A.
T1 - Mechanisms of low susceptibility to the disinfectant benzalkonium chloride in a multidrug-resistant environmental isolate of Aeromonas hydrophila
N2 - Excessive discharge of quaternary ammoniumdisinfectants such as benzalkonium chloride (BAC) into aquatic systems can trigger several physiological responses in environmental microorganisms. In this study, we isolated a less-susceptible strain of Aeromonas hydrophila to BAC, designated as INISA09, froma wastewater treatment plant in Costa Rica. We characterized its phenotypic response upon exposure to three dierent concentrations of BAC and characterizedmechanisms related to its resistance using genomic and proteomic approaches. The genome of the strain, mapped against 52 dierent sequenced A. hydrophila strains, consists of approximately 4.6Mb with 4,273 genes. We found a massive genome rearrangement and thousands of missense mutations compared to the reference strain A. hydrophila ATCC 7966.
We identified 15,762 missense mutations mainly associated with transport, antimicrobial resistance, and outer membrane proteins.
In addition, a quantitative proteomic analysis revealed a significant upregulation of several efflux pumps and the downregulation of porins when the strain was exposed to three BAC concentrations.Other genes related tomembrane fatty acid metabolism and redox metabolic reactions also showed an altered expression.
Our findings indicate that the response of A. hydrophila INISA09 to BAC primarily occurs at the envelop level, which is the primary target of BAC. Our study elucidates the mechanisms of antimicrobial susceptibility in aquatic environments against a widely used disinfectant and will help better understand howbacteria can adapt to biocide pollution. To our knowledge, this is the first study addressing the resistance to BAC in an environmental A. hydrophila isolate. We propose that this bacterial species could also serve as a new model to study antimicrobial pollution in aquatic environments.
KW - Antimicrobial resistance
KW - Bacteria
KW - Disinfection
KW - Biocides
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578555
DO - https://doi.org/10.3389/fmicb.2023.1180128
SN - 1664-302X
VL - 14
SP - 1
EP - 18
PB - Frontiers SA
CY - Lausanne
AN - OPUS4-57855
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Selina B. I.
A1 - Täschner, Tom
A1 - Nordholt, Niclas
A1 - Schreiber, Frank
T1 - Differential Selection for Survival and for Growth in Adaptive Laboratory Evolution Experiments With Benzalkonium Chloride
N2 - Biocides are used to control microorganisms across different applications, but emerging resistance may pose risks for those applications. Resistance to biocides has commonly been studied using adaptive laboratory evolution (ALE) experiments with growth at subinhibitory concentrations linked to serial subculturing. It has been shown recently that Escherichia coli adapts to repeated lethal stress imposed by the biocide benzalkonium chloride (BAC) by increased survival (i.e., tolerance) and not by evolving the ability to grow at increased concentrations (i.e., resistance). Here, we investigate the contributions of evolution for tolerance as opposed to resistance for the outcome of ALE experiments with E. coli exposed to BAC. We find that BAC concentrations close to the half maximal effective concentration (EC50, 4.36 μg mL−1) show initial killing (~40%) before the population resumes growth. This indicates that cells face a two‐fold selection pressure: for increased survival and for increased growth. To disentangle the effects of both selection pressures, we conducted two ALE experiments: (i) one with initial killing and continued stress close to the EC50 during growth and (ii) another with initial killing and no stress during growth. Phenotypic characterization of adapted populations showed that growth at higher BAC concentrations was only selected for when BAC was present during growth. Whole genome sequencing revealed distinct differences in mutated genes across treatments. Treatments selecting for survival‐only led to mutations in genes for metabolic regulation (cyaA) and cellular structure (flagella fliJ), while treatments selecting for growth and survival led to mutations in genes related to stress response (hslO and tufA). Our results demonstrate that serial subculture ALE experiments with an antimicrobial at subinhibitory concentrations can select for increased growth and survival. This finding has implications for the design of ALE experiments to assess resistance risks of antimicrobials in different scenarios such as disinfection, preservation, and environmental pollution.
KW - Antimicrobial resistance
KW - Bacteria
KW - Standardization
KW - Biocides
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615496
DO - https://doi.org/10.1111/eva.70017
VL - 17
IS - 10
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-61549
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nikolic, Nela
A1 - Dal Co, Alma
A1 - Kiviet, Daniel J.
A1 - Bergmiller, Tobias
A1 - Littmann, Sten
A1 - Kuypers, Marcel M. M.
A1 - Ackermann, Martin
A1 - Schreiber, Frank
T1 - Cell-to-cell variation and specialization in sugar metabolism in clonal bacterial populations
N2 - While we have good understanding of bacterial metabolism at the population level, we know little about the metabolic behavior of individual cells: do single cells in clonal populations sometimes specialize on different metabolic pathways? Such metabolic specialization could be driven by stochastic gene expression and could provide individual cells with growth benefits of specialization. We measured the degree of phenotypic specialization in two parallel metabolic pathways, the assimilation of glucose and arabinose. We grew Escherichia coli in chemostats, and used isotope-labeled sugars in combination with nanometer-scale secondary ion mass spectrometry and mathematical modeling to quantify sugar assimilation at the single-cell level. We found large variation in metabolic activities between single cells, both in absolute assimilation and in the degree to which individual cells specialize in the assimilation of different sugars. Analysis of transcriptional reporters indicated that this variation was at least partially based on cell-to-cell variation in gene expression. Metabolic differences between cells in clonal populations could potentially reduce metabolic incompatibilities between different pathways, and increase the rate at which parallel reactions can be performed.
KW - Metabolism
KW - Escherichia coli
KW - Phenotypic diversity
KW - Phenotypic heterogeneity
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438873
UR - http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1007122
DO - https://doi.org/10.1371/journal.pgen.1007122
SN - 1553-7404
VL - 13
IS - 12
SP - e1007122, 1
EP - e1007122, 24
PB - Public Library of Science
CY - Cambridge, United Kingdom
AN - OPUS4-43887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.
A1 - Camin, B.
A1 - Hansen, L.
A1 - Heuser, M.
A1 - Lopez-Galilea, I.
A1 - Ruttert, B.
A1 - Theisen, W.
A1 - Fedelich, Bernard
T1 - Refinement and Experimental Validation of a Vacancy Model of Pore Annihilation in Single-Crystal Nickel-Base Superalloys during Hot Isostatic Pressing
N2 - Initially, as-cast and homogenized single crystals of nickel-base superalloy CMSX-4 are subjected to hot isostatic pressing at 1288 °C. Two series of experiments are conducted: under the same pressure of 103 MPa but with different durations, between 0.5 and 6 h, and under different pressures, between 15 and 150 MPa, but for the same time of 0.5 h. The porosity annihilation is investigated metallographically and by high-resolution synchrotron X-ray tomography. The obtained experimental results are compared with the predictions of the vacancy model proposed recently in the group. Herein, the model is further refined by coupling with X-ray tomography. The model describes the evolution of the pore arrays enclosed in the 3D synchrotron tomograms during hot isostatic pressing and properly predicts the time and stress dependences of the pore annihilation kinetics. The validated model and the obtained experimental results are used for selecting the optimal technological parameters such as applied pressure and processing time
KW - Superalloys
KW - HIP
KW - Single-Crystal
KW - Diffusion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526859
DO - https://doi.org/10.1002/adem.202100211
VL - 23
IS - 7
SP - 211
AN - OPUS4-52685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ahmadian, A.
A1 - Scheiber, D.
A1 - Zhou, X.
A1 - Gault, B.
A1 - Darvishi Kamachali, Reza
A1 - Romaner, L.
A1 - Ecker, W.
A1 - Dehm, G.
A1 - Liebscher, C. H.
T1 - Interstitial segregation has the potential to mitigate liquid metal embrittlement in iron
N2 - The embrittlement of metallic alloys by liquid metals leads to catastrophic material failure and severely impacts their structural integrity. The weakening of grain boundaries by the ingress of liquid metal and preceding segregation in the solid are thought to promote early fracture. However, the potential of balancing between the segregation of cohesion-enhancing interstitial solutes and embrittling elements inducing grain boundary decohesion is not understood. Here, we unveil the mechanisms of how boron segregation mitigates the detrimental effects of the prime embrittler, zinc, in a Σ5 [0 0 1] tilt grain boundary in α −Fe (4 at.% Al). Zinc forms nanoscale segregation patterns inducing structurally and compositionally complex grain boundary states. Ab-initio simulations reveal that boron hinders zinc segregation and compensates for the zinc induced loss in grain boundary cohesion. Our work sheds new light on how interstitial solutes intimately modify grain boundaries, thereby opening pathways to use them as dopants for preventing disastrous material failure.
KW - Materials Modelling
KW - Liquid Metal Embrittlement
KW - Alloy Safety
KW - CALPHAD
KW - Microstructure Design
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573576
DO - https://doi.org/10.1002/adma.202211796
SN - 0935-9648
IS - e2211796
PB - Wiley online library
AN - OPUS4-57357
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Agudo Jácome, Leonardo
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Fries, S. G.
T1 - Data regarding the experimental findings compared with CALPHAD calculations of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy
N2 - This contribution contains the raw data used to compare experimental results with thermodynamic calculations using the CALPHAD method, which is related to the research article “The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: experimental findings and comparison with calculations using the CALPHAD method” [1] , and therefore this article can be used as a basis for interpreting the data contained therein. The AlMo0.5NbTa0.5TiZr refractory superalloy was characterized in the cast and annealed condition (1400 °C for 24 h) in order to measure grain size and to identify and measure the size and area fraction of the phases present. The raw data of this article include X-ray diffraction (XRD) measurements, microstructural characterization by scanning and transmission electron microscopy (SEM and TEM), and elemental analysis by energy dispersive X-ray spectroscopy (EDX). XRD includes the determination of phases and the lattice parameters (A2, B2, and hexagonal structure). Microstructural analysis by scanning and transmission electron microscopy includes (1) identification of composition, size, and volume fraction of the present phases and (2) determination of grain size. Based on these experimental data, it is possible to identify similarities and discrepancies with the data calculated using the CALPHAD method for the alloy under study in Ref. [1] , which provides the basis for better and more efficient development of reliable databases.
KW - Transmission electron microscopy
KW - Scanning electron microscopy
KW - Microstructural characterization
KW - Refractory high entropy alloys
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568009
DO - https://doi.org/10.1016/j.dib.2022.108858
SN - 2352-3409
VL - 46
SP - 1
EP - 19
PB - Elsevier
CY - Amsterdam
AN - OPUS4-56800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kianinejad, Kaveh
A1 - Darvishi Kamachali, Reza
A1 - Khedkar, Abhinav
A1 - Manzoni, Anna Maria
A1 - Agudo Jácome, Leonardo
A1 - Schriever, Sina
A1 - Saliwan Neumann, Romeo
A1 - Megahed, Sandra
A1 - Heinze, Christoph
A1 - Kamrani, Sepideh
A1 - Fedelich, Bernard
T1 - Creep anisotropy of additively manufactured Inconel-738LC: Combined experiments and microstructure-based modeling
N2 - The current lack of quantitative knowledge on processing-microstructure–property relationships is one of the major bottlenecks in today’s rapidly expanding field of additive manufacturing. This is centrally rooted in the nature of the processing, leading to complex microstructural features. Experimentally-guided modeling can offer reliable solutions for the safe application of additively manufactured materials. In this work, we combine a set of systematic experiments and modeling to address creep anisotropy and its correlation with microstructural characteristics in laser-based powder bed fusion (PBF-LB/M) additively manufactured Inconel-738LC (IN738LC). Three sample orientations (with the tensile axis parallel, perpendicular, and 45° tilted, relative to the building direction) are crept at 850 °C, accompanied by electron backscatter secondary diffraction (EBSD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) investigations. A crystal plasticity (CP) model for Ni-base superalloys, capable of modeling different types of slip systems, is developed and combined with various polycrystalline representative volume elements (RVEs) built on the experimental measurements. Besides our experiments, we verify our modeling framework on electron beam powder bed fusion (PBF-EB/M) additively manufactured Inconel-738LC. The results of our simulations show that while the crystallographic texture alone cannot explain the observed creep anisotropy, the superlattice extrinsic stacking faults (SESF) and related microtwinning slip systems play major roles as active deformation mechanisms. We confirm this using TEM investigations, revealing evidence of SESFs in crept specimens. We also show that the elongated grain morphology can result in higher creep rates, especially in the specimens with a tilted tensile axis.
KW - Additive manufactured Ni-base superalloys
KW - Creep
KW - Crystal plasticity
KW - Superlattice extrinsic stacking faults
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601576
DO - https://doi.org/10.1016/j.msea.2024.146690
SN - 0921-5093
VL - 907
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-60157
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocano, Patricia
A1 - Fries, S. G.
A1 - Lopez-Galilea, I.
A1 - Darvishi Kamachali, Reza
A1 - Roik, J.
A1 - Agudo Jácome, Leonardo
T1 - The AlMo0.5NbTa0.5TiZr refractory high entropy superalloy: Experimental findings and comparison with calculations using the CALPHAD method
N2 - Detailed microstructural characterization of the AlMo0.5NbTa0.5TiZr refractory high entropy superalloy in the as-cast state is reported for first time and compared with the state annealed at 1400 oC for 24 h. The former shows a dendritic structure, with a mixture of A2/B2 phases < 20 nm in both the dendritic and interdendritic regions. A mostly amorphous phase, rich in Al and Zr, is found within the interdendritic region. The annealed state reproduced the combination of A2/B2/Al-Zr-rich phases reported previously. Calculations from two relevant ThermoCalc databases were compared with the experimental results. Equilibrium calculations were compared with results for the annealed alloy, whereas solidification paths calculated using Scheil-Gulliver model were used for comparison with the as-cast alloy. A previously hypothesized spinodal decomposition during cooling as the mechanism responsible for the patterned A2/B2 microstructure is confirmed via the CALPHAD calculations, pointing to its use as an efficient design tool for such alloys. Finally, the comparison between the experimental and computational findings allowed better understanding the solidification path and equilibrium stability of this alloy, giving a base to make better decisions on the field of new refractory superalloy design.
KW - CALPHAD database analysis
KW - Refractory superalloys
KW - Chemically complex alloy
KW - Characterization
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545906
DO - https://doi.org/10.1016/j.matdes.2022.110593
SN - 1873-4197
VL - 217
SP - 1
EP - 13
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54590
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jordan, T.
A1 - Askar, Enis
A1 - Holtappels, Kai
A1 - Deeg, S.
A1 - Jopen, M.
A1 - Stoll, U.
A1 - Reinecke, E.-A.
A1 - Krause, U.
A1 - Beyer, M.
A1 - Markus, D.
T1 - Stand der Kenntnisse und Technik bezüglich Wasserstoffsicherheit
N2 - Die Einführung von Wasserstoff als sicherer Energieträger braucht eine robuste Wissensbasis, darauf aufgebaute Werkzeuge zur Auslegung und Sicherheitsbewertung von Wasserstofftechnologien und ein international harmonisiertes Regelwerk. Viele der innovativen Technologien implizieren Wasserstoff bei hohen Drücken und/oder kryogenen Temperaturen, mit denen in verteilten Anwendungen erstmalig private Nutzer in Kontakt kommen. Um überkonservative, teure Sicherheitslösungen zu vermeiden, gleichzeitig aber die Einsetzbarkeit und Sicherheit von Wasserstoffanwendungen zu demonstrieren und die Akzeptanz für die Technologie aufrecht zu halten, muss auch die Sicherheitsforschung mit den Trends der technologischen Entwicklung Schritt halten, oder sie besser noch antizipieren. So beschreibt dieser Überblicksartikel nicht nur den gegenwärtigen Stand der Kenntnisse und Technik bezüglich Wasserstoffsicherheit, sondern auch ihre Weiterentwicklung.
KW - Alternative Energieträger
KW - Explosionsschutz
KW - Flüssigwasserstoff
KW - Unfallszenarien
KW - Wasserstoffspeicherung
KW - Sicherheitsbewertung
KW - Regelsetzung
KW - Gefährdungs- und Risikobeurteilung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593629
DO - https://doi.org/10.1002/cite.202300141
SN - 0009-286X
VL - 96
IS - 1-2
SP - 1
EP - 20
PB - Wiley-VCH
AN - OPUS4-59362
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kozachynskyi, Volodymyr
A1 - Staubach, Dario
A1 - Esche, Erik
A1 - Biegler, Lorenz T.
A1 - Repke, Jens-Uwe
T1 - Parameter estimation in dynamic multiphase liquid–liquid equilibrium systems
N2 - Modeling dynamic systems with a variable number of liquid phases is a challenging task, especially in scenarios where the model is designed for optimization tasks such as parameter estimation. Although there exist methods to model the appearance and disappearance of liquid phases in dynamic systems, they usually require integer variables. In this work, the smoothed continuous approach (SCA) is developed for use with a large number of solvers, since it relies only on continuous variables. To demonstrate the applicability of the new method, the SCA is then applied to model the batch esterification of acetic acid with 1-propanol to water and propyl acetate, and to estimate the reaction parameters. Since the mixture may separate into two liquid phases during the course of the reaction, the parameters are estimated with information on the liquid compositions of both separated liquid phases, which improves the accuracy of the parameter estimates and opens new possibilities for optimal experimental design.
KW - Parameter Estimation
KW - Uncertainty
KW - Dynamic Modeling
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650059
DO - https://doi.org/10.1016/j.compchemeng.2025.109485
SN - 0098-1354
VL - 206
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-65005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - European Food Safety Authority (EFSA),
A1 - European Centre for Disease Prevention and Control (ECDC),
A1 - European Chemicals Agency (ECHA),
A1 - European Environment Agency (EEA),
A1 - European Medicines Agency (EMA),
A1 - European Commission's Joint Research Centre (JRC),
T1 - Scientific report - Impact of the use of azole fungicides, other than as human medicines, on the development of azole‐resistant Aspergillus spp.
N2 - The use of azoles in the European Union and European Economic Area (EU/EEA) other than as human medicines has raised concerns about emergence and spread of azole‐resistant Aspergillus species. EU agencies, with the support of JRC, reviewed the evidence and provided conclusions and recommendations on this topic. Although incomplete, data from 2010 to 2021 showed that around 120,000 tonnes of azoles were sold in EU/EEA for uses other than as human medicines. The majority are used as plant protection products (119,000 tonnes), with a stable temporal trend. Evidence supported a link between environmental azole exposure and cross‐resistance selection to medical azoles in Aspergillus species (primarily shown for A. fumigatus). Prevalence of azole‐resistant A. fumigatus in human A. fumigatus infections ranges from 0.7% to 63.6% among different disease presentations and geographic regions; mortality rates range from 36% to 100% for invasive aspergillosis (IA). It was concluded that azole usage outside the human domain is likely or very likely to contribute to selection of azole‐resistant A. fumigatus isolates that could cause severe disease like IA. Environmental hotspots for resistance selection were identified, including stockpiling of agricultural waste and their possible use as soil amendment/fertiliser for certain agricultural crops (for plant protection products) and freshly cut wood (for biocides). Recommendations were formulated on measures to prevent and control selection of azole resistance in A. fumigatus, including implementation of good agricultural/horticultural practices, proper agricultural and wood waste storage and management, and on approval of new azole fungicides or renewal of existing fungicides. Recommendations on topics to be covered by studies provided when submitting applications for the approval of azole fungicides were listed. For the evaluation of such studies within the approval procedure, a preliminary framework for risk assessment was developed and should be further refined. Data gaps and uncertainties were identified, alongside with respective recommendations to address them.
KW - Antimicrobial surfaces
KW - Biocides
KW - Antimicrobial resistance
KW - Azoles
KW - Fungi
KW - Wood preservatives
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652175
DO - https://doi.org/10.2903/j.efsa.2025.9200
SN - 1831-4732
VL - 23
IS - 1
SP - 1
EP - 35
PB - Wiley
CY - Hoboken, NJ
AN - OPUS4-65217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winkler, Nicolas P.
A1 - Neumann, Patrick P.
A1 - Albizu, Natalia
A1 - Schaffernicht, Erik
A1 - Lilienthal, Achim J.
T1 - GNN-DM: A Graph Neural Network Framework for Real-World Gas Distribution Mapping
N2 - Gas distribution mapping (GDM) is essential for industrial safety and environmental monitoring, as it enables real-time hazard detection and air quality assessment. Traditional GDM methods, such as kernel-based techniques, struggle to reconstruct complex gas plume dynamics accurately. While deep learning has shown promise for GDM, two critical challenges hinder its practical use: the scarcity of available training data and the incompatibility of conventional architectures with irregular sensor layouts. To address these limitations, we propose GNN-DM, a graph neural network-based model for GDM that incorporates the relational structure of sensor networks to infer high-resolution maps from minimal, irregular inputs. The model is pretrained on synthetic gas dispersion data generated from measured wind data and fine-tuned on two industrial datasets collected on a ferry car deck and in a hot rolling mill. Compared with established GDM techniques, GNN-DM achieves higher accuracy on synthetic and real-world data, highlighting the potential of graph-based learning for practical gas mapping applications.
KW - Environmental monitoring
KW - Sensor networks
KW - Transfer learning
KW - Deep learning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647363
DO - https://doi.org/10.1109/JSEN.2025.3617158
SN - 1530-437X
VL - 25
IS - 22
SP - 42171
EP - 42179
PB - Institute of Electrical and Electronics Engineers (IEEE)
AN - OPUS4-64736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grzelec, Małgorzata
A1 - Haas, Sylvio
A1 - Helman-Ważny, Agnieszka
T1 - Application of scanning small-angle X-ray scattering in the identification of sheet formation techniques in historical papers
N2 - Among writing substrates produced historically in different regions of the world, paper is one of the most complex materials. Its complexity results not only from a variety of highly processed ingredients, which can be used in its production, but also from a variety of methods in which these materials are combined to form the fibrillar network referred to as paper. While material identification methods are well established in the analysis of historical papers, the identification of manufacturing technologies is still an under-researched topic, that requires the development of appropriate methods and measurement protocols. This paper reports on the results of a research project aimed at the application of synchrotron scanning small angle X-ray scattering (SAXS) method in the characterization of paper structure, with emphasis on the assessment of fibrillar orientation as a marker characteristic for different, historical papermaking technologies. The main objective of this study consists of the development of a measurement protocol involving the SAXS technique complemented by other analytical methods in the characterization of the fibrous paper structure.
KW - SAXS
KW - Paper analysis
KW - Papermaking technology
KW - Fiber orientation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651594
DO - https://doi.org/10.1007/s00339-024-08157-4
SN - 0947-8396
VL - 131
IS - 1
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65159
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Graebner, Maraike
A1 - Giese, Marcel
A1 - Lorenz, Svenja
A1 - Treutler, Kai
A1 - Schröpfer, Dirk
A1 - Wesling, Volker
A1 - Kannengießer, Thomas
T1 - Wear resistance of modified NiMoCrSi claddings in relation to the resulting surface machinability via ultrasonic-assisted milling
N2 - In the field of plastics processing, extruder screws are subjected to significant wear stresses. The extruder screw is the main wear component in those production machines and is usually coated with intermetallic wear protection alloys composed of Ni-based alloys, specifically Colmonoy C56 PTA (NiMoCrSi). There is a growing demand for providing an economic machinability of these alloys to achieve defined contours with a sufficient surface integrity. Recent investigations exhibit promising results applying ultrasonic milling for such hard-to-cut materials. The Colmonoy C56 is modified by various alloying additions Ti, Nb, Mo, Hf, and Al, and then cladded on a steel S355 via Plasma Transferred Arc process. The effect of alloying additions on the microstructure is analyzed regarding their resistance to abrasive and adhesive wear. With Miller test ASTM G75 the influence of alloying elements on resistance to abrasive wear for two abrasive materials is investigated (high-grade corundum F220 and quartz powder). The wear loss is not increased for additions of Nb and Ti compared to the base material C56. Modifications with Hf or Al reduces the resistance to abrasive wear and significantly increases material loss. The extruder screw is also subject to adhesive wear, which can be quantified by means of the pin-roll test. It is demonstrated that the addition of Hf, for example, contributes to a reduction in wear loss. Aim of the investigations is to find suitable modifications for the wear claddings of C56 for a sufficient machineability, without compemising the wear resistant. The machinability is considerably affected by the alloy additions, and is determined using ultrasonic-assisted milling. The addition of hafnium reduces machinability, i.e. significantly increases cutting forces. The incorporation of Nb exhibits a significant reduction of cutting forces, and results in reduced tool wear and an enhanced of surface integrity (roughness, density of defects, residual stresses).
KW - Colmonoy C56
KW - PTA welding
KW - Adhesive wear
KW - Abrasive wear
KW - Ultrasonic-assisted milling process
KW - Surface integrity
KW - Service life and efficiency
KW - Substitution of critical raw materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651530
DO - https://doi.org/10.1016/j.wear.2025.205830
SN - 0043-1648
VL - 571
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65153
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vöse, Markus
A1 - Fedelich, Bernard
A1 - Otto, F.
A1 - Eggeler, G.
T1 - Micromechanical modeling of creep damage in a copper-antimony alloy
N2 - A micromechanical model of creep induced grain boundary damage is proposed, which allows for the simulation of creep damage in a polycrystal with the finite element method. Grain boundary cavitation and sliding are considered via a micromechanically motivated cohesive zone model, while the grains creep following the slip system theory. The model has been calibrated with creep test data from pure Cu single crystals and a coarse-grained polycrystalline Cu-Sb alloy. The test data includes porosity measurements and estimates of grain boundary sliding. Finally, the model has been applied to Voronoi models of polycrystalline structures. In particular the influence of grain boundary sliding on the overall creep rate is demonstrated.
T2 - ECF20 - 20th European conference on fracture
CY - Trondheim, Norway
DA - 28.06.2014
KW - Creep damage
KW - Grain boundary sliding
KW - Cohesive zone
KW - Micromechanical model
KW - Polycrystal
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309914
DO - https://doi.org/10.1016/j.mspro.2014.06.006
SN - 2211-8128
VL - 3
SP - 21
EP - 26
PB - Curran
CY - Red Hook, NY, USA
AN - OPUS4-30991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Volkmar
A1 - Askar, Enis
A1 - Tashqin, T.
T1 - Sicherheitstechnische Eigenschaften von Gemischen aus Wasserstoff und Erdgas
N2 - Bei der Power-to-Gas-Technologie wird überschüssiger Strom aus erneuerbaren Ener-gien durch Elektrolyse von Wasser in Wasserstoff umgewandelt. Dieser Wasserstoff kann als „chemischer Energiespeicher“ dienen und rückverstromt werden oder aber in das Erdgasnetz eingespeist werden. Die BAM hat die Auswirkungen von Wasserstoffzu-sätzen zum Erdgas im Hinblick auf den Explosionsschutz untersucht und sicherheitstechnische Kenngrößen für Erdgas-Wasserstoff-Gemische bestimmt.
Von besonderem Interesse waren dabei die Explosionsgrenzen, die Sauerstoffgrenzkonzentration, die maximalen Explosionsdrücke, die KG-Werte und die Normspaltweiten. Für die Messungen sind zwei Modellgase eingesetzt worden, reines Methan und ein Modell-Erdgas mit Anteilen höherer Kohlenwasserstoffe. Sie repräsentieren die Bandbreite der in Deutschland eingesetzten Erdgase.
Die Untersuchungen ergaben, dass bei einem Zusatz von bis zu 10 Mol-% Wasserstoff keine der untersuchten Kenngrößen signifikant beeinflusst wird. Die Gemische haben nur geringfügig erweiterte Explosionsbereiche und bleiben, wie die reinen Erdgase, in der Explosionsgruppe IIA. Auch die maximalen Explosionsdrücke und die zeitlichen Druckanstiege bei den Gasexplosionen werden nur wenig beeinflusst.
T2 - Kolloquium zur chemischen und physikalischen Sicherheitstechnik
CY - Berlin, Germany
DA - 14.06.2016
KW - Wasserstoff
KW - Erdgasnetz
KW - Energiespeicherung
KW - Explosionsschutz
KW - Sicherheitstechnische Kenngrößen
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-373099
SN - 978-3-9817853-5-7
SN - 0938-5533
VL - 2016
SP - 60
EP - 67
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin, Germany
AN - OPUS4-37309
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
T1 - Melting upon Coalescence of Solid Nanoparticles
N2 - The large surface-to-volume ratio of nanoparticles is understood to be the source of many interesting phenomena. The melting temperature of nanoparticles is shown to dramatically reduce compared to bulk material. Yet, at temperatures below this reduced melting point, a liquid-like atomic arrangement on the surface of nanoparticles is still anticipated to influence its properties. To understand such surface effects, here, we study the coalescence of Au nanoparticles of various sizes using molecular dynamics simulations. Analysis of the potential energy and Lindemann index distribution across the nanoparticles reveals that high-energy, high-mobility surface atoms can enable the coalescence of nanoparticles at temperatures much lower than their corresponding melting point. The smaller the nanoparticles, the larger the difference between their melting and coalescence temperatures. For small enough particles and/or elevated enough temperatures, we found that the coalescence leads to a melting transition of the two nominally solid nanoparticles, here discussed in relation to the heat released due to the surface reduction upon the coalescence and the size dependence of latent heat. Such discontinuous melting transitions can lead to abrupt changes in the properties of nanoparticles, important for their applications at intermediate temperatures.
KW - Nanoparticles
KW - Molecular Dynamics
KW - Surface-induced Melting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552183
DO - https://doi.org/10.3390/solids3020025
VL - 3
IS - 2
SP - 361
EP - 373
PB - MDPI
AN - OPUS4-55218
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elfetni, Seif
A1 - Darvishi Kamachali, Reza
T1 - PINNs-MPF: A Physics-Informed Neural Network framework for Multi-Phase-Field simulation of interface dynamics
N2 - We present PINNs-MPF framework, an application of Physics-Informed Neural Networks (PINNs) to handle Multi-Phase-Field (MPF) simulations of microstructure evolution. A combination of optimization techniques within PINNs and in direct relation to MPF method are extended and adapted. The numerical resolution is realized through a multi-variable time-series problem by using fully discrete resolution. Within each interval, space, time, and phases/grains are treated separately, constituting discrete subdomains. PINNs-MPF is equipped with an extended multi-networking (parallelization) concept to subdivide the simulation domain into multiple batches, with each batch associated with an independent NN trained to predict the solution. To ensure continuity across the spatio-temporal-phasic subdomains, a Master NN efficiently is to handle interactions among the multiple networks and facilitates the transfer of learning. A pyramidal training approach is proposed to the PINN community as a dual-impact method: to facilitate the initialization of training when dealing with multiple networks, and to unify the solution through an extended transfer of learning. Furthermore, a comprehensive approach is adopted to specifically focus the attention on the interfacial regions through a dynamic meshing process, significantly simplifying the tuning of hyper-parameters, serving as a key concept for addressing MPF problems using machine learning. We perform a set of systematic simulations that benchmark foundational aspects of MPF simulations, i.e., the curvature-driven dynamics of a diffuse interface, in the presence and absence of an external driving force, and the evolution and equilibrium of a triple junction. The proposed PINNs-MPF framework successfully reproduces benchmark tests with high fidelity and Mean Squared Error (MSE) loss values ranging from 10^−6 to 10^−4 compared to ground truth solutions.
KW - Machine learning
KW - PINNs
KW - Phase-field method
KW - Microstructure evolution
KW - Parallel training
KW - Neural networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629740
DO - https://doi.org/10.1016/j.enganabound.2025.106200
SN - 0955-7997
VL - 176
SP - 1
EP - 22
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62974
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elfetni, Seifallah
A1 - Darvishi Kamachali, Reza
T1 - PINNs-MPF: An Efficient Physics-Informed Machine Learning-based Solver for Multi-Phase-Field Simulations using Tensorflow
N2 - This paper introduces PINNs-MPF, a novel Machine Learning-based solver designed for Multi-Phase-Field (MPF) and diffuse interface simulations, offering innovative approaches to address complex challenges in addressing microstructure evolution in polycrystalline materials using Machine Learning. The framework not only surpasses current limitations in handling multi-phase problems but also allows for potential upscaling to tackle more intricate scenarios. Developed in Python, the related code leverages optimized libraries like TensorFlow, showcasing efficiency and potential scalability in materials science and engineering simulations. This framework, integrating advanced techniques such as multi-networking and training optimization, setting a new standard in predictive capabilities and understanding complex physical phenomena.
KW - Machine Learning
KW - Microstructure Simulation
KW - Phase Field
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631917
DO - https://doi.org/10.1016/j.simpa.2025.100753
SN - 2665-9638
VL - 24
SP - 1
EP - 4
PB - Elsevier B.V.
AN - OPUS4-63191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhou, X.
A1 - Wei, Y.
A1 - Kühbach, M.
A1 - Zhao, H.
A1 - Vogel, F.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
A1 - Raabe, D.
A1 - Gault, B.
T1 - Revealing in-plane grain boundary composition features through machine learning from atom probe tomography data
N2 - Grain boundaries (GBs) are planar lattice defects that govern the properties of many types of polycrystalline materials. Hence, their structures have been investigated in great detail. However, much less is known about their chemical features, owing to the experimental difficulties to probe these features at the atomic length scale inside bulk material specimens. Atom probe tomography (APT) is a tool capable of accomplishing this task, with an ability to quantify chemical characteristics at near-atomic scale. Using APT data sets, we present here a machine-learning-based approach for the automated quantification of chemical features of GBs. We trained a convolutional neural network (CNN) using twenty thousand synthesized images of grain interiors, GBs, or triple junctions. Such a trained CNN automatically detects the locations of GBs from APT data. Those GBs are then subjected to compositional mapping and analysis, including revealing their in-plane chemical decoration patterns. We applied this approach to experimentally obtained APT data sets pertaining to three case studies, namely, Ni-P, Pt-Au, and Al-Zn-Mg-Cu alloys. In the first case, we extracted GB specific segregation features as a function of misorientation and coincidence site lattice character. Secondly, we revealed interfacial excesses and in-plane chemical features that could not have been found by standard compositional analyses. Lastly, we tracked the temporal evolution of chemical decoration from early-stage solute GB segregation in the dilute limit to interfacial phase separation, characterized by the evolution of complex composition patterns. This machine-learning-based approach provides quantitative, unbiased, and automated access to GB chemical analyses, serving as an enabling tool for new discoveries related to interface thermodynamics, kinetics, and the associated chemistry-structure-property relations.
KW - Machine learning
KW - Digitalization
KW - Alloy microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543049
DO - https://doi.org/10.1016/j.actamat.2022.117633
SN - 1359-6454
VL - 226
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-54304
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, L.
A1 - Darvishi Kamachali, Reza
A1 - Li, Z.
A1 - Zhang, Z.
T1 - Grain boundary energy effect on grain boundary segregation in an equiatomic high-entropy alloy
N2 - Grain boundary (GB) Segregation has a substantial effect on the microstructure evolution and properties of polycrystalline alloys. The mechanism of nanoscale segregation at the various GBs in multicomponent alloys is of great challenge to reveal and remains elusive so far. To address this issue, we studied the GB segregation in a representative equiatomic FeMnNiCoCr high-entropy alloy (HEA) aged at 450 °C. By combining transmission Kikuchi diffraction, atom probe tomography analysis and a density-based thermodynamics modeling, we uncover the nanoscale segregation behavior at a series of well-characterized GBs of different characters. No segregation occurs at coherent twin boundaries; only slight nanoscale segregation of Ni takes place at the low-angle GBs and vicinal \Sigma 29b coincidence site lattice GBs. Ni and Mn show cosegregation of high levels at the general high-angle GBs with a strong depletion in Fe, Cr, and Co. Our density-based thermodynamic model reveals that the highly negative energy of mixing Ni and Mn is the main driving force for nanoscale cosegregation to the GBs. This is further assisted by the opposite segregation of Ni and Cr atoms with a positive enthalpy of mixing. It is also found that GBs of higher interfacial energy, possessing lower atomic densities (higher disorder and free volume), show higher segregation levels. By clarifying the origins of GB segregations in the FeMnNiCoCr HEA, the current work provides fundamental ideas on nanoscale segregation at crystal defects in multicomponent alloys.
KW - Thermodynamics
KW - High-Entropy Alloys
KW - Grain Boundary Segregation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508827
DO - https://doi.org/10.1103/PhysRevMaterials.4.053603
VL - 4
IS - 5
SP - 053603
PB - American Physical Society
AN - OPUS4-50882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindrachuk, Vitaliy
A1 - Darvishi Kamachali, Reza
T1 - Mean-field modeling and phase-field simulation of grain growth under directional driving forces
N2 - Directional grain growth is a common phenomenon in the synthetic and natural evolution of various polycrystals. It occurs in the presence of an external driving force, such as a temperature gradient, along which grains show a preferred, yet competitive, growth. Novel additive manufacturing processes, with intense, localized energy deposition, are prominent examples of when directional grain growth can occur, beneath the melting pool. In this work, we derive a phenomenological mean-field model and perform 3D phase-field simulations to investigate the directional grain growth and its underlying physical mechanisms. The effect of the intensity of driving force is simulated and systematically analyzed at the evolving growth front as well as various cross-sections perpendicular to the direction of the driving force. We found that although the directional growth significantly deviates from normal grain growth, it is still governed by a power law relation α tⁿ with an exponent n ~ 0.6–0.7. The exponent n exhibits a nontrivial dependence on the magnitude of the directional driving force, such that the lowest growth exponent is observed for intermediate driving forces. We elaborate that this can originate from the fact that the forces at grain boundary junctions evolve out of balance under the influence of the directional driving force. With increasing the driving forces, the growth exponent asymptotically approaches a value of n ≈ 0.63, imposed by the largest possible grain aspect ratio for given grain boundary energies. The current combined mean-field and phase-field framework pave the way for future exploration in broader contexts such as the evolution of complex additively manufactured microstructures.
KW - Additive manufacturing
KW - Phase-field simulation
KW - Grain growth
KW - Mean-field modelling
KW - Directional grain growth
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593210
DO - https://doi.org/10.1016/j.mtla.2023.101989
SN - 2589-1529
VL - 33
SP - 1
EP - 10
PB - Elsevier
AN - OPUS4-59321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Murugan, Jegatheesan
A1 - Darvishi Kamachali, Reza
T1 - High‑throughput investigation of grain boundary segregation landscape in the Fe–Ni–Cr system
N2 - Understanding phase stability in multicomponent alloy systems, particularly at internal interfaces, remains a major challenge in materials science. Grain boundary (co-)segregation is a critical factor influencing interfacial stability, often leading to microstructural degradation and safety concerns. In this study, we investigate segregation behavior in the face-centered cubic (FCC) Fe–Ni–Cr alloy system, a foundational system for many steels, superalloys, and high-entropy alloys. CALPHAD-integrated density-based phase-field model is extended to compute the segregation of Fe, Ni, and Cr at grain boundaries as a function of the bulk composition, with the relative GB density serving as a key parameter representing grain boundary character. A high-throughput computational screening is performed across the stable compositional space at 723 K, 1023 K, and 1323 K. The results reveal a rich and temperature-sensitive segregation landscape, with element-specific enrichment and depletion patterns that vary with alloy composition. Notably, opposite segregation trends between Ni and Cr, and frequent co-segregation of Fe and Ni, are observed at lower temperatures. The developed framework captures the coupled effects of temperature, chemical interactions, grain boundary structure, and enthalpy-entropy compensation on segregation and GB phase stability. The origin and implications of these phenomena are discussed in terms of the underlying thermodynamic driving forces.
KW - Segregation Engineering
KW - Grain boundary segregation
KW - Thermodynamics
KW - CALPHAD
KW - Fe--Ni--Cr alloys
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646404
DO - https://doi.org/10.1007/s10853-025-11717-5
SN - 1573-4803
SP - 1
EP - 21
PB - Springer Science + Business Media
CY - Dordrecht [u.a.]
AN - OPUS4-64640
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feldmann, Titus
A1 - Fedelich, Bernard
A1 - Epishin, A.
T1 - Simulation of Hot Isostatic Pressing in a Single-Crystal Ni Base Superalloy with the Theory of Continuously Distributed Dislocations Combined with Vacancy Diffusion
N2 - Single-crystal components made of nickel base superalloys contain pores after casting and homogenization heat treatment. Hot isostatic pressing (HIP), which is carried above the γ' -solvus temperature of the alloy, is industrially applied to reduce porosity. A modeling of HIP based on continuously distributed dislocations is developed in a 2D setting. Glide and climb of straight-edge dislocations, as well as vacancy diffusion, are the deformation mechanisms taken into account.
Thereby, dislocation glide is controlled by dragging a cloud of large atoms, and climb is controlled by vacancy diffusion. Relying on previous investigations of the creep behavior at HIP temperatures, it is assumed that new dislocations are nucleated at low-angle boundaries (LAB) and move through subgrains until they either reach the opposite LABs or react with other dislocations and annihilate.
Vacancies are created at the pore surface and diffuse through the alloy until they are either consumed by climbing dislocations or disappear at the LABs. The field equations are solved by finite elements. It is shown that pore shrinking is mostly controlled by vacancy diffusion as the shear stresses at the LABs are too low to
nucleate a sufficient amount of dislocations.
KW - Nickel-base superalloys
KW - HIP
KW - Dislocation
KW - Creep
KW - Model
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542309
DO - https://doi.org/10.1002/adem.202101341
VL - 2022
PB - Wiley
AN - OPUS4-54230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Epishin, A.I.
A1 - Link, T.
A1 - Fedelich, Bernard
A1 - Svetlov, I.L.
A1 - Golubovskiy, E.R.
T1 - Hot isostatic pressing of single-crystal nickel-base superalloys: mechanism of pore closure and effect on mechanical properties
N2 - Pore annihilation was investigated in the single-crystal nickel-base superalloy CMSX-4. HIP tests at 1288 °C/103 MPa were interrupted at different times, then the specimens were investigated by TEM, metallography and density measurements. The kinetics of pore annihilation was determined. The pore closure mechanism was identified as plastic deformation on the octahedral slip systems. A model describing the kinetics of pore closure has been developed on the base of crystal plasticity and large strain theory. Mechanical tests with the superalloy CMSX-4 and the Ru-containing superalloy VGM4 showed, that HIP significantly increases the fatigue life at low temperatures but has no effect on creep strength.
T2 - Eurosuperalloys 2014 - 2nd European symposium on superalloys and their applications
CY - Giens, France
DA - 12.05.2014
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-316410
DO - https://doi.org/10.1051/matecconf/20141408003
N1 - Serientitel: MATEC Web of conferences – Series title: MATEC Web of conferences
VL - 14
SP - 08003-1
EP - 08003-6
PB - EDP Sciences
AN - OPUS4-31641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
A1 - da Silva, A.
A1 - McEniry, E.
A1 - Gault, B.
A1 - Neugebauer, J.
A1 - Raabe, D.
T1 - Segregation-assisted spinodal and transient spinodal phase separation at grain boundaries
N2 - Segregation to grain boundaries affects their cohesion, corrosion, and embrittlement and plays a critical role in heterogeneous nucleation. In order to quantitatively study segregation and low-dimensional phase separation at grain boundaries, here, we apply a density-based phase-field model. The current model describes the grain-boundary thermodynamic properties based on available bulk thermodynamic data, while the grain-boundary-density profile is obtained using atomistic simulations. To benchmark the performance of the model, Mn grain-boundary segregation in the Fe–Mn system is studied. 3D simulation results are compared against atom probe tomography measurements conducted for three alloy compositions. We show that a continuous increase in the alloy composition results in a discontinuous jump in the segregation isotherm. The jump corresponds to a spinodal Phase separation at grain boundary. For alloy compositions above the jump, we reveal an interfacial transient spinodal phase separation.
The transient spinodal phenomenon opens opportunities for knowledge-based microstructure design through the chemical manipulation of grain boundaries. The proposed density-based model provides a powerful tool to study thermodynamics and kinetics of segregation and phase changes at grain boundaries.
KW - Grain Boundary Spinodal
KW - Densty-based Thermodynamics
KW - Microstrucrue Design
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519497
DO - https://doi.org/10.1038/s41524-020-00456-7
VL - 6
IS - 1
SP - 191
PB - Nature
AN - OPUS4-51949
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wang, Lei
A1 - Darvishi Kamachali, Reza
T1 - Density-based grain boundary phase diagrams: Application to Fe-Mn-Cr, Fe-Mn-Ni, Fe-Mn-Co, Fe-Cr-Ni and Fe-Cr-Co alloy systems
N2 - Phase diagrams are the roadmaps for designing bulk phases. Similar to bulk, grain boundaries can possess various phases, but their phase diagrams remain largely unknown. Using a recently introduced density-based model, here we devise a strategy for computing multi-component grain boundary phase diagrams based on available bulk (CALPHAD) thermodynamic data. Fe-Mn-Cr, Fe-Mn-Ni, Fe-Mn-Co, Fe-Cr-Ni and Fe-Cr-Co alloy systems, as important ternary bases for several trending steels and high-entropy alloys, are studied. We found that despite its solute segregation enrichment, a grain boundary can have lower solubility limit than its corresponding bulk, promoting an interfacial chemical decomposition upon solute segregation. This is revealed here for the Fe-Mn-base alloy systems. The origins of this counter-intuitive feature are traced back to two effects, i.e., the magnetic ordering effect and the low cohesive energy of Mn solute element. Different aspects of interfacial phase stability and GB co-segregation in ternary alloys are investigated as well. We show that the concentration gradient energy contributions reduce segregation level but increase grain boundary solubility limit, stabilizing the GB against a chemical decomposition. Density-based grain boundary phase diagrams offer guidelines for systematic investigation of interfacial phase changes with applications to microstructure defects engineering.
KW - Densty-based Thermodynamics
KW - Microstrucrue Design
KW - Grain Boundary Phase Diagram
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522207
DO - https://doi.org/10.1016/j.actamat.2021.116668
SN - 1359-6454
VL - 207
SP - 116668
PB - Elsevier Ltd.
AN - OPUS4-52220
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jacobson, D.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
T1 - Extending Density Phase-Field Simulations to Dynamic Regimes
N2 - Density-based phase-field (DPF) methods have emerged as a technique for simulating grain boundary thermodynamics and kinetics. Compared to the classical phase-field, DPF gives a more physical description of the grain boundary structure and chemistry, bridging CALPHAD databases and atomistic simulations, with broad applications to grain boundary and segregation engineering. Notwithstanding their notable progress, further advancements are still warranted in DPF methods. Chief among these are the requirements to resolve its performance constraints associated with solving fourth-order partial differential equations (PDEs) and to enable the DPF methods for simulating moving grain boundaries. Presented in this work is a means by which the aforementioned problems are addressed by expressing the density field of a DPF simulation in terms of a traditional order parameter field. A generic DPF free energy functional is derived and used to carry out a series of equilibrium and dynamic simulations of grain boundaries in order to generate trends such as grain boundary width vs. gradient energy coefficient, grain boundary velocity vs. applied driving force, and spherical grain radius vs. time. These trends are compared with analytical solutions and the behavior of physical grain boundaries in order to ascertain the validity of the coupled DPF model. All tested quantities were found to agree with established theories of grain boundary behavior. In addition, the resulting simulations allow for DPF simulations to be carried out by existing phase-field solvers.
KW - CALPHAD
KW - Phase-field modelling
KW - Phase-Field Simulations
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581365
DO - https://doi.org/10.3390/met13081497
VL - 13
SP - 1
EP - 16
AN - OPUS4-58136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezhov, Alexander
A1 - Kulisch, D.
A1 - Goncharov, A.
A1 - Zhutovsky, S.
T1 - A Comparative Study of Factors Influencing Hydration Stoppage of Hardened Cement Paste
N2 - There is no consensus on which hydration stoppage method is optimal to preserve the microstructure and mineral composition of samples, especially considering the specific aspects of different testing methods, such as TGA, MIP, or XRD. This paper presents a quantitative comparison between the most popular hydration stoppage strategies and parameters such as the sample piece size, the soaking time in a solvent, and the type, as examined on cement paste hydrated for 7 days. It was found that the carbonation appears either for samples smaller than 2.36 mm and bigger than 4.75 mm or samples soaked in a solvent for longer than 1 h. Fast solvent replacement leads to ettringite diminution and total pore volume increase. Among others, solvent replacement with subsequent gentle heating under a vacuum was found to be the most efficient, whereas it was experimentally demonstrated that isopropyl alcohol stops hydration faster than ethanol and acetone.
KW - Hydration stoppage
KW - Solvent replacement
KW - Soaking time
KW - Sample piece size
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582430
DO - https://doi.org/10.3390/su15021080
VL - 15
IS - 2
SP - 1
EP - 21
PB - MDPI
CY - Basel, Switzerland.
AN - OPUS4-58243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Strangfeld, Christoph
A1 - Schönsee, Eric
A1 - Jeyifous, Olubunmi Anthony
A1 - Mezhov, Alexander
A1 - Hüsken, Götz
T1 - Introduction of a monitoring system for Bingham fluids in additive manufacturing with concrete
N2 - Freeform additive manufacturing of concrete structures is a rising technology in civil engineering with several fascinating advantages. Nonetheless, to ensure reliability and structural integrity, standards and quality control are required in the future to bring this technology into the market. As the concrete is manufactured continuously, continuous quality control of the printing process is also required, i.e. comprehensive process monitoring. At BAM, a test rig will be installed, enabling the printing of concrete structures with a maximum size of 2 m x 1 m x 1 m (l x w x h). Here, process monitoring is the focus of the test rig. In this study, we show the results of the first pump tests, including the measurement of several parameters such as temperature and pressure along the supply system, i.e. from the concrete pump to the printer head.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Additive manufacturing of concrete
KW - Process monitoring
KW - Non-destructive testing
KW - Bingham fluid
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556367
SP - 1
EP - 12
AN - OPUS4-55636
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Poli, Marco
A1 - Grätz, Rainer
A1 - Schröder, Volkmar
T1 - An experimental study on safety-relevant parameters of turbulent gas explosion venting at elevated initial pressure
N2 - The effects of a gas explosion in enclosures like vessels can be limited e.g. by gas explosion venting systems. The major design step of this constructive explosion protection method is to determine the required vent area, which depends significantly on whether turbulent combustion exists. However, current standards like NFPA 68 or EN 14994 are applicable only to limited boundary conditions and as far as possible only to laminar flame propagation. Difficulties arise in the assessment or predictability of gas explosion hazard when turbulence occurs. In this research especially venting at elevated initial pressure has been shown to accelerated flame propagations and therefore, to a considerably higher reduced pressure. Therefore, it is essential to provide a broader data base of turbulent combustion and explosion behavior to verify the existing rules or to determine their safety-relevant parameters. For a better safety assessment or design of protective systems the turbulent combustion and accelerated gas explosion behaviour of quiescent methane and hydrogen in air were investigated at initial pressures up to 8 bar using vessels up to 100 litres. In particular a systematic study was performed to investigate the influence of turbulence on the overpressure development during accelerated gas explosion. Moreover, the present study consider the position of the spark igniters, the burning velocity and the maximum pressure rise for different concentration of fuel as well as the size of orifice and/or vent area. A choice of experimental tests showed under the investigated conditions that not only turbulence inducing obstacles but also over sized vent areas could lead to an increased pressure development and therefore to an inacceptable safety state.
T2 - 20th International Congress of Chemical and Process Engineering CHISA 2012
CY - Prague, Czech Republic
DA - 25.08.2012
KW - Gas explosion venting
KW - Turbulent combustion
KW - Obstacles
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-264288
DO - https://doi.org/10.1016/j.proeng.2012.07.398
SN - 1877-7058
VL - 42
SP - 90
EP - 99
PB - Elsevier
CY - Amsterdam
AN - OPUS4-26428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meira, Maria Fernanda Cavalcante
A1 - Fernandes, Gabriela Leal Peres
A1 - de Camargo, Andréa Simone Stucchi
A1 - Ravaro, Leandro Piaggi
A1 - Arai, Marylyn Setsuko
A1 - Navarro, Maria Fidela de Lima
A1 - Brighenti, Fernanda Lourenção
A1 - Oliveira, Analú Barros de
A1 - Danelon, Marcelle
ED - Stucchi de Camargo, Andrea
T1 - Modification of restorative glass ionomer cement with zinc oxide nanoparticles and calcium glycerophosphate microparticles: in vitro assessment of mechanical properties and antimicrobial activity
N2 - Abstract The incorporation of bioactive agents into resin-modified glass ionomer cement (RMGIC) is a promising strategy to improve its mechanical strength and biofilm control, especially for patients with active dental caries. Objective This study aimed to evaluate the effects of incorporating ZnONPs and CaGP into RMGIC on its mechanical and microbiological properties. Design Six groups were tested: 1) RMGIC (without CaGP/ZnONPs); 2) RMGIC-1.0%ZnONPs; 3) RMGIC-2.0%ZnONPs; 4) RMGIC-3.0%CaGP; 5) RMGIC-3.0%CaGP-1.0%ZnONPs; and 6) RMGIC-3.0%CaGP-2.0%ZnONPs. The compressive strength (CS), diametral tensile strength (DTS), and surface hardness (SH) were evaluated after 24 hours and 7 days. Antimicrobial and antibiofilm activity were evaluated using agar diffusion and biofilm metabolic activity (XTT) assays. Results After 24 hours, all the groups showed similar DTS values (p0.05), except for RMGIC-3.0%CaGP-1.0%ZnONPs, which showed the highest DTS value (p<0.05). Comparing 24 hours and 7 days, the DTS values of RMGIC-3.0%CaGP-2.0%ZnONPs, RMGIC-3.0%CaGP, and RMGIC-3.0%CaGP-2.0%ZnONPs were similar (p=0.360). After 24 hours, the RMGIC group showed the CS highest value, followed by RMGIC-2.0%ZnONPs (p < 0.05). After 7 days, the RMGIC-3.0%CaGP-1.0%ZnONPs group exhibited the highest CS value, approximately 15% higher than RMGIC (p<0.05). The RMGIC-1.0%ZnONPs group exhibited significantly higher SH at 24 hours (p=0.621). At 7 days, the highest SH value was observed for the RMGIC-3.0%CaGP-1.0%ZnONPs group (p<0.05). Regarding antimicrobial and antibiofilm activity, including results from biofilm metabolism assays, the RMGIC-3.0%CaGP-1.0%ZnONPs group demonstrated the most effective antimicrobial and inhibitory effects (p<0.05). Conclusion This study demonstrated that adding ZnONPs and CaGP to RMGIC enhanced its mechanical and antimicrobial and antibiofilm properties, suggesting enhanced mechanical performance and improved protection against cariogenic biofilms—critical factors for successful restorative treatments. Therefore, the addition of ZnONPs and CaGP is a promising strategy to develop advanced restorative materials that improve clinical outcomes, especially for patients with active dental caries.
KW - Resin-modified glass ionomer cement
KW - Phosphate
KW - Zinc oxide nanoparticles
KW - Biofilm
KW - Mechanical properties
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652799
DO - https://doi.org/10.1590/1678-7757-2025-0356
SN - 1678-7765
VL - 33
SP - 1
EP - 14
PB - FapUNIFESP (SciELO)
AN - OPUS4-65279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn S.
A1 - Brambilla, Gabriel V.
A1 - Corrêa, Bruna Carolina
A1 - Merízio, Leonnam G.
A1 - Inada, Natalia M.
A1 - de Camargo, Andrea S. S.
T1 - A Dual-Mode “Turn-On” Ratiometric Luminescent Sensor Based on Upconverting Nanoparticles for Detection and Differentiation of Gram-Positive and Gram-Negative Bacteria
N2 - Infectious bacterial diseases, intensified by antibiotic resistance, cause millions of deaths annually and pose risks beyond human health, including water and food contamination. Current diagnostics are often slow, require complex equipment, and lack specificity, highlighting the need for rapid and reliable detection methods. To address this, we developed a luminescent sensor based on NaYF4 upconverting nanoparticles (UCNPs) doped with Er3+ or Tm3+, coated with COOH-PEG4-COOH, and functionalized with vancomycin (Van) or polymyxin-B (Poly) to selectively target Gram-positive and Gram-negative bacteria, respectively. Gold nanoparticles (AuNPs) served as quenchers, enabling a ratiometric “turn-on” mechanism: upon bacterial binding, the UCNP emission, initially quenched by AuNPs, was partially restored. This allowed Differentiation through changes in the green/red (G/R) ratio for Er-UCNP@PEG4-Van and the blue/red (B/R) ratio for Tm-UCNP@PEG4-Poly. The sensor distinguished between Gram-positive and Gram-negative bacteria over a wide concentration range (0.05 to 5 × 105 CFU/mL) and showed high correlation with actual bacterial counts (r = 0.99 for S. aureus, r = 0.91 for E. coli). This platform is a potential fast, selective, and reliable tool for bacterial detection in clinical and environmental settings.
KW - Lminescent sensor
KW - Upconverting nanoparticles
KW - Gram-positive and Gram-negative bacteria
KW - Ratiometric luminescent sensors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652785
DO - https://doi.org/10.1021/acsomega.5c07006
SN - 2470-1343
VL - 10
IS - 39
SP - 46040
EP - 46050
PB - American Chemical Society (ACS)
AN - OPUS4-65278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Afantitis, A.
A1 - Melagraki, G.
A1 - Isigonis, P.
A1 - Tsoumanis, A.
A1 - Varsou, D. D.
A1 - Valsami-Jones, E.
A1 - Papadiamantis, A.
A1 - Ellis, L.-J. A.
A1 - Sarimveis, H.
A1 - Doganis, P.
A1 - Karatzas, P.
A1 - Tsiros, P.
A1 - Liampa, I.
A1 - Lobaskin, V.
A1 - Greco, D.
A1 - Serra, A.
A1 - Kinaret, P. A. S.
A1 - Saarimäki, L. A.
A1 - Grafström, R.
A1 - Kohonen, P.
A1 - Nymark, P.
A1 - Willighagen, E.
A1 - Puzyn, T.
A1 - Rybinska-Fryca, A.
A1 - Lyubartsev, A.
A1 - Jensen, K. A.
A1 - Brandenburg, J. G.
A1 - Lofts, S.
A1 - Svendsen, C.
A1 - Harrison, S.
A1 - Maier, D.
A1 - Tamm, K.
A1 - Jänes, J.
A1 - Sikk, L.
A1 - Dusinska, M.
A1 - Longhin, E.
A1 - Rundén-Pran, E.
A1 - Mariussen, E.
A1 - El Yamani, N.
A1 - Unger, Wolfgang
A1 - Radnik, Jörg
A1 - Tropsha, A.
A1 - Cohen, Y.
A1 - Lesczynski, J.
A1 - Hendren, C. O.
A1 - Wiesner, M.
A1 - Winkler, D.
A1 - Suzuki, N.
A1 - Yoon, T. H.
A1 - Choi, J.-S.
A1 - Sanabria, N.
A1 - Gulumian, M.
A1 - Lynch, I.
T1 - NanoSolveIT Project: Driving nanoinformatics research to develop innovative and integrated tools for in silico nanosafety assessment
N2 - Nanotechnology has enabled the discovery of a multitude of novel materials exhibiting unique physicochemical (PChem) properties compared to their bulk analogues. These properties have led to a rapidly increasing range of commercial applications; this, however, may come at a cost, if an association to long-term health and environmental risks is discovered or even just perceived. Many nanomaterials (NMs) have not yet had their potential adverse biological effects fully assessed, due to costs and time constraints associated with the experimental assessment, frequently involving animals. Here, the available NM libraries are analyzed for their suitability for integration with novel nanoinformatics approaches and for the development of NM specific Integrated Approaches to Testing and Assessment (IATA) for human and environmental risk assessment, all within the NanoSolveIT cloud-platform. These established and well-characterized NM libraries (e.g. NanoMILE, NanoSolutions, NANoREG, NanoFASE, caLIBRAte, NanoTEST and the Nanomaterial Registry (>2000 NMs)) contain physicochemical characterization data as well as data for several relevant biological endpoints, assessed in part using harmonized Organisation for Economic Co-operation and Development (OECD) methods and test guidelines.
Integration of such extensive NM information sources with the latest nanoinformatics methods will allow NanoSolveIT to model the relationships between NM structure (morphology), properties and their adverse effects and to predict the effects of other NMs for which less data is available. The project specifically addresses the needs of regulatory agencies and industry to effectively and rapidly evaluate the exposure, NM hazard and risk from nanomaterials and nano-enabled products, enabling implementation of computational ‘safe-by-design’ approaches to facilitate NM commercialization.
KW - Nanoinformatics
KW - Hazard assessment
KW - (Quantitative) Structure-Active Relationships
KW - Safe-by-design
KW - Predictive modelling
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505952
DO - https://doi.org/10.1016/j.csbj.2020.02.023
VL - 18
SP - 583
EP - 602
PB - Elsevier B.V.
AN - OPUS4-50595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Agostini, G.
A1 - Radnik, Jörg
T1 - Spectroscopy in Catalysis
N2 - Knowledge-based catalyst development is always an interaction between preparation, analysis and catalytic testing. Only if these three factors fit together can success be expected. For the analytic side of this triangle, spectroscopic methods play a crucial role. Whereas with diffraction, scattering and microscopy, decisive insights into the structure and morphology of the catalysts can be obtained, spectroscopy produces new knowledge about the chemical nature of the catalyst, e.g., its bonding and valence states.
KW - Spectroscopy
KW - Catalysis
KW - Operando
KW - In situ
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506507
DO - https://doi.org/10.3390/catal10040408
VL - 10
IS - 4
SP - 408
PB - MDPI
CY - Basel
AN - OPUS4-50650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohammadifar, E.
A1 - Ahmadi, V.
A1 - Gholami, M.F.
A1 - Oehrl, A.
A1 - Kolyvushko, O.
A1 - Nie, C.
A1 - Donskyi, Ievgen
A1 - Herziger, S.
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Böttcher, C.
A1 - Rabe, J.P.
A1 - Osterrieder, K.
A1 - Azab, W.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Graphene-Assisted Synthesis of 2D Polyglycerols as Innovative Platforms for Multivalent Virus Interactions
N2 - 2D nanomaterials have garnered widespread attention in biomedicine and
bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively.
A single-layer hyperbranched polyglycerol containing azide functional
groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes Simplex
virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus Inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.2D nanomaterials have garnered widespread attention in biomedicine and bioengineering due to their unique physicochemical properties. However, poor functionality, low solubility, intrinsic toxicity, and nonspecific interactions at biointerfaces have hampered their application in vivo. Here, biocompatible polyglycerol units are crosslinked in two dimensions using a graphene-assisted strategy leading to highly functional and water-soluble polyglycerols nanosheets with 263 ± 53 nm and 2.7 ± 0.2 nm average lateral size and thickness, respectively.
A single-layer hyperbranched polyglycerol containing azide functional groups is covalently conjugated to the surface of a functional graphene template through pH-sensitive linkers. Then, lateral crosslinking of polyglycerol units is carried out by loading tripropargylamine on the surface of graphene followed by lifting off this reagent for an on-face click reaction. Subsequently, the polyglycerol nanosheets are detached from the surface of graphene by slight acidification and centrifugation and is sulfated to mimic heparin sulfate proteoglycans. To highlight the impact of the two-dimensionality of the synthesized polyglycerol sulfate nanosheets at nanobiointerfaces, their efficiency with respect to herpes Simplex virus type 1 and severe acute respiratory syndrome corona virus 2 inhibition is compared to their 3D nanogel analogs. Four times stronger in virus Inhibition suggests that 2D polyglycerols are superior to their current 3D counterparts.
KW - 2D Materials
KW - Graphene template
KW - Multivalency
KW - Polyglycerol
KW - Virus inhibition
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527726
DO - https://doi.org/10.1002/adfm.202009003
VL - 31
IS - 32
SP - 2009003
PB - Wiley VCH
AN - OPUS4-52772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jungnickel, R.
A1 - Mirabella, Francesca
A1 - Stockmann, Jörg Manfred
A1 - Radnik, Jörg
A1 - Balasubramanian, K.
T1 - Graphene‑on‑gold surface plasmon resonance sensors resilient to high‑temperature annealing
N2 - Gold films coated with a graphene sheet are being widely used as sensors for the detection of label-free binding interactions using surface plasmon resonance (SPR). During the preparation of such sensors, it is often essential to subject the sensor chips to a high-temperature treatment in order to ensure a clean graphene surface. However, sensor chips used currently, which often use chromium as an adhesion promoter, cannot be subjected to temperatures above 250 °C, because under such conditions, chromium is found to reorganize and diffuse to the surface, where it is easily oxidized, impairing the quality of SPR spectra. Here we present an optimized preparation strategy involving a three-cycle tempering coupled with chromium (oxide) etching, which allows the graphene-coated SPR chips to be annealed up to 500 °C with little deterioration of the surface morphology. In addition, the treatment delivers a surface that shows a clear enhancement in spectral response together with a good refractive index sensitivity. We demonstrate the applicability of our sensors by studying the kinetics of avidin–biotin binding at different pH repeatedly on the same chip. The possibility to anneal can be exploited to recover the original surface after sensing trials, which allowed us to reuse the sensor for at least six cycles of biomolecule adsorption.
KW - Surface plasmon resonance
KW - Graphene
KW - Sensing
KW - Surface regeneration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564585
DO - https://doi.org/10.1007/s00216-022-04450-4
SN - 1618-2642
SP - 1
EP - 7
PB - Springer
AN - OPUS4-56458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nickl, Philip
A1 - Hilal, T.
A1 - Olal, D.
A1 - Donskyi, Ievgen
A1 - Radnik, Jörg
A1 - Ludwig, K.
A1 - Haag, R.
T1 - A New Support Film for Cryo Electron Microscopy Protein Structure Analysis Based on Covalently Functionalized Graphene
N2 - Protein adsorption at the air–water interface is a serious problem in cryogenic electron microscopy (cryoEM) as it restricts particle orientations in the vitrified ice-film and promotes protein denaturation. To address this issue, the preparation of a graphene-based modified support film for coverage of conventional holey carbon transmission electron microscopy (TEM) grids is presented. The chemical modification of graphene sheets enables the universal covalent anchoring of unmodified proteins via inherent surface-exposed lysine or cysteine residues in a one-step reaction. Langmuir–Blodgett (LB) trough approach is applied for deposition of functionalized graphene sheets onto commercially available holey carbon TEM grids. The application of the modified TEM grids in single particle analysis (SPA) shows high protein binding to the surface of the graphene-based support film. Suitability for high resolution structure determination is confirmed by SPA of apoferritin. Prevention of protein denaturation at the air–water interface and improvement of particle orientations is shown using human 20S proteasome, demonstrating the potential of the support film for structural biology.
KW - Functionalized graphene
KW - Transmission electron microsocpy
KW - Protein structure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566443
DO - https://doi.org/10.1002/smll.202205932
SN - 1613-6810
SP - 2205932
PB - Wiley VCH
AN - OPUS4-56644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Castells-Gil, Javier
A1 - Zhu, Jinjie
A1 - Itskou, Ioanna
A1 - Wolpert, Emma H.
A1 - Hunter, Robert D.
A1 - Tidey, Jeremiah P.
A1 - Pedersen, Angus
A1 - Solvay, Elisa
A1 - Tyrrell, Helen
A1 - Petit, Camille
A1 - Barrio, Jesús
T1 - Impact of N-heterocyclic amine modulators on the structure and thermal conversion of a zeolitic imidazole framework
N2 - The zeolitic imidazole framework-8 (ZIF-8) is a crystalline porous material that has been widely employed as template to fabricate porous nitrogen-doped carbons with high microporosity via thermal treatment at high temperatures. The properties of the carbon scaffold are influenced by the pore structure and chemical composition of the parent ZIF. However, the narrow pore size distribution and microporous nature from ZIF-8 often results in low mesopore volume, which is crucial for applications such as energy storage and conversion. Here we show that insertion of N-heterocyclic amines can disrupt the structure of ZIF-8 and dramatically impact the chemical composition and pore structure of the nitrogen-doped carbon frameworks obtained after high-temperature pyrolysis. Melamine and 2,4,6-triaminopyrimidine were chosen to modify the ZIF-8 structure owing to their capability to both coordinate metal ions and establish supramolecular interactions. Employing a wide variety of physical characterization techniques we observed that melamine results in the formation of a mixed-phase material comprising ZIF-8, Zn(Ac)6(Mel)2 and crystallized melamine, while 2,4,6-triaminopyrimidine induces the formation of defects, altering the pore structure. Furthermore, the absence of heterocyclic amine in the ZIF-8 synthesis leads to a new crystalline phase, unreported to date. The thermal conversion of the modified ZIFs at 1000 °C leads to nitrogen-doped carbons bearing Zn moieties with increased surface area, mesopore volume and varying degree of defects compared to ZIF-8 derived carbon. This work therefore highlights both the versatility of heterocyclic amines to modify the structure of framework materials as well as their role in tuning pore structure in nitrogen-doped carbons, paving the way to targeted design of high-performance electrodes for energy storage and conversion.
KW - Zeolitic imidazole framework
KW - Heterocyclic amine
KW - Triaminopyrimidine
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639177
DO - https://doi.org/10.1039/D5TA04831A
SN - 2050-7488
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Braga, Daniel S.
A1 - Pedersen, Angus
A1 - Riyaz, Mohd
A1 - Barrio, Jesús
A1 - Bagger, Alexander
A1 - Neckel, Itamar T.
A1 - Mariano, Thiago M.
A1 - Winkler, Manuel E. G.
A1 - Stephens, Ifan E. L.
A1 - Titirici, Maria‐Magdalena
A1 - Nagao, Raphael
T1 - In situ structural evolution and activity descriptor of atomically dispersed catalysts during nitrate electroreduction
N2 - Single‐Atom Catalysts (SAC) have emerged as a promising class of materials for various catalytic applications, including the electrochemical nitrate reduction reaction (eNO3RR) and consequently ammonia production. While the efficiency and selectivity of these materials have been extensively highlighted for the eNO3RR, the in situ evolution to their structure and composition during electrocatalysis is largely unexplored and lacks catalyst design principles. To solve this, we investigated a series of high utilization metal‐nitrogen‐carbon (MNC) SACs (M = Cr, Fe, Co, Ni, and Cu) for eNO3RR. Except for CuNC, which selectively produced nitrite, all catalysts exhibited Faradaic efficiencies (FE) for ammonia exceeding 50%. NiNC demonstrated the highest performance (FE of 78.0 ± 2.9% at −0.4 V versus reversible hydrogen electrode (RHE) at pH 13 and maximum ammonia production rate of 615.7 ± 176.5 µmol·h−1·, corresponding to an energy efficiency of 15.1 ± 1.4% at −0.6 VRHE), followed by CoNC. In situ Synchrotron X‐ray fluorescence (SXRF) mapping at various cathodic potentials (from open circuit potential to 0.0 VRHE and then −0.6 VRHE at 100 mV steps) revealed significant mobility of Ni within the carbon matrix, leading to the formation of metallic clusters from 0.0 VRHE. Similar in situ metal clustering is observed for CoNC. Structure‐activity plots are generated from both MNC literature and results obtained here, finding a clear trend between OH binding energy and turnover frequency, with the high activity of NiNC and CoNC in this work explained by their stronger OH binding in the metallic structure compared to their SAC coordination. This work therefore, reveals the structure‐activity‐stability of MNCs for eNO3RR and provides a simple descriptor for identifying highly active eNO3RR catalysts and their in situ structural evolution.
KW - Single atom
KW - Nitrate reduction
KW - Structure-activity-selectivity
KW - In situ
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640353
DO - https://doi.org/10.1002/advs.202510282
SN - 2198-3844
VL - 12
IS - 39
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64035
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rua-Ibarz, Ana
A1 - Nakadi, Flávio V.
A1 - Bolea-Fernandez, Eduardo
A1 - Bazo, Antonio
A1 - Battistella, Beatrice
A1 - Matiushkina, Anna
A1 - Resch-Genger, Ute
A1 - Abad Andrade, Carlos Enrique
A1 - Resano, Martín
T1 - Discrete entity analysis via microwave-induced nitrogen plasma–mass spectrometry in single-event mode
N2 - In this work, single-event microwave-induced nitrogen plasma–mass spectrometry (single-event MINP-MS) was evaluated for the first time for the analysis of discrete entities such as nanoparticles, biological cells, and microplastics. Nitrogen (N2) effectively overcomes Ar-based polyatomic interferences, enabling (ultra)trace element determination of Fe and Se using their most abundant isotopes, 56Fe (91.66%) and 80Se (49.82%). Iron oxide nanoparticles (Fe2O3 NPs) ranging from 20 to 70 nm were accurately characterized, with excellent agreement with established sizing techniques, such as transmission electron microscopy (TEM) and dynamic light scattering (DLS). A limit of detection (LoD) of 8.6 ag for Fe─equivalent to an LoDsize of 19 nm for Fe2O3─was achieved, which is significantly lower than recent values reported for high-end quadrupole-based ICP-MS. Selenium nanoparticles (SeNPs) of 150 and 250 nm were also accurately characterized, without the N2-based plasma experiencing issues handling relatively large metallic NPs (linearity, R2 = 0.9994). Se-enriched yeast cells (SELM-1 certified reference material) were successfully analyzed via single-cell MINP-MS using external calibration based on SeNPs and a transport efficiency-independent approach. In addition, 2–3 μm polystyrene (PS) and polytetrafluoroethylene (PTFE) were accurately sized by monitoring 12C+, confirming the method’s suitability for handling micrometer-sized polymeric materials (microplastics). The average duration of individual events (680 ± 160 μs) suggests that the digestion of individual entities in N2-based plasmas is comparable to that in Ar-based plasmas. These results open new avenues for this instrumentation as an alternative to ICP ionization sources, also in the context of discrete entity analysis.
KW - Microwave-Induced Nitrogen Plasma
KW - Discrete entity analysis
KW - Particle/droplet event counting
KW - Comparison to SP-ICP-MS methodologies
KW - Nitrogen plasma vs. argon ICP trade-offs
KW - Trace elemental quantification at the single-entity level
KW - Time-resolved mass spectrometry for discrete entities
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643825
DO - https://doi.org/10.1021/acs.analchem.5c04341
SN - 0003-2700
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-64382
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abad Andrade, Carlos Enrique
A1 - Jegielka, Dennis
A1 - Aloysius, Allen
A1 - Recknagel, Sebastian
T1 - SI-traceable total analysis of nitrate and nitrite by isotope dilution optical spectroscopy and its application to Berlin surface waters
N2 - Accurate nitrate and nitrite data support water-quality regulation, yet routine methods rely on external calibration and rarely achieve SI traceability. We report a calibration-free determination of nitrate and nitrite by combining isotope dilution with high-resolution continuum-source graphite furnace molecular absorption spectrometry (ID-HR-CS-GF-MAS). A 15N-enriched nitrate spike (its concentration verified by reverse isotope dilution against the standard reference material NIST 3185) provides the SI link, and it is gravimetrically added to samples; nitrate and residual nitrite are converted in situ to nitric oxide (NO), whose 215 nm band is recorded at a pixel resolution of λ/Δλ ≈ 140 000. The 0.2127 nm shift between 14NO and 15NO electronic spectra is resolved, and a three-latent-variable partial least squares regression model yields the 15N/14N ratio with 0.3% precision. Instrumental LoD values of 4.8 ng (14N) and 3.2 ng (15N) translate to a method LoD of 4.8 ng of nitrogen (equivalent to 1.05 mg L−1 NO3− for a 20 μL aliquot). The furnace program allows for successive drying/pyrolysis loops, so additional 20 μL aliquots can be layered onto the graphite platform. Alternatively, a 10 mL anion-exchange solid-phase extraction step concentrates nitrate and nitrite fivefold, allowing for the analysis of even lower sample concentrations. Results for four certified reference materials (2.9 to 1000 mg L−1 NO3−) agreed with certified values, giving relative expanded uncertainties of 2 to 4%. Analysis of twenty Berlin surface-water samples revealed concentrations ranging from 0.10 to 7.3 mg L−1 NO3−, indicating that the Panke River and Teltow Canal are the primary sources of nitrogen. ID-HR-CS-GF-MAS thus delivers ID-MS-level accuracy in a few minutes per run with bench-top optics, and, with optional on-platform or SPE pre-concentration, extends SI-traceable nitrate/nitrite monitoring into the low-ng regime.
KW - Isotope dilution
KW - Nitrate and nitrite determination
KW - SI-traceable quantification
KW - Calibration-free analysis
KW - Water quality
KW - Berlin surface waters
KW - NO molecular absorption bands
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643785
DO - https://doi.org/10.1039/D5JA00252D
SN - 0267-9477
VL - 40
IS - 10
SP - 2692
EP - 2701
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64378
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marschall, Niklas
A1 - Murugan, Jegatheesan
A1 - Darvishi Kamachali, Reza
T1 - Incorporating elasticity into the thermodynamics and phase diagrams of multi-component systems
N2 - Elastic energy plays a critical role in determining phase stability in compositionally complex alloys. However, quantifying elastic contributions in multi-component systems and incorporating them into phase diagram construction remain challenging. In this study, we present a generalized elastic energy formalism tailored for multi-component alloys, which can be directly and efficiently integrated with CALPHAD thermodynamic databases and existing frameworks such as Thermo-Calc (Andersson et al., 2002), Pandat (Cao et al., 2009) or FactSage (Bale et al., 2016). This elasticity formalism can also be introduced as a post-processing layer in open-source software such as pyCALPHAD (Otis and Liu, 2017) and Kawin (Ury et al., 2023) , enabling elastic assessments in multi-component systems. We apply our framework for constructing the phase diagram of quinary Fe–Mn–Ni–Co–Cu alloy system, utilizing convex hull and Hessian matrix under elastic considerations. Our results reveal that incorporating elastic energy leads to an expansion of both the spinodal region and the miscibility gap. These are governed by the intricate interplay of chemical and elastic driving forces: We found that Mn and Ni contribute strongly to chemical stabilization, while Cu and Co tend to destabilize the alloy, especially at low Mn concentrations. The stabilizing effect of Fe is also pronounced in Mn-deficient regions. Acting as a destabilizing factor, the elastic energy is primarily driven by the presence of Mn, underscoring its multifaceted role in thermodynamic stability. In Mn-rich compositions, Cu markedly reduces the elastic energy contribution. Combined with CALPHAD infrastructures, the current framework offers a practical pathway to improve the predictive accuracy of phase stability and transformations in complex multi-component alloys.
KW - Elastic energy
KW - HEA
KW - CALPHAD
KW - Elastic spinodal
KW - Elastic miscibility gap
KW - Elastic phase diagram
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643339
DO - https://doi.org/10.1016/j.mtla.2025.102546
SN - 2589-1529
VL - 44
SP - 1
EP - 18
PB - Elsevier
CY - Amsterdam, Niederlande
AN - OPUS4-64333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tidblad, Johan
A1 - Moya Núñez, Alice
A1 - de la Fuente, Daniel
A1 - Ebell, Gino
A1 - Flatlandsmo Berglen, Tore
A1 - Grøntoft, Terje
A1 - Hans, Ulrik
A1 - Christodoulakis, Ioannis
A1 - Kajánek, Daniel
A1 - Kreislová, Kateřina
A1 - Kwiatkowski, Lech
A1 - La Torreta, Teresa
A1 - Lutze, Rafał
A1 - Pinar Larrubia, Guadalupe
A1 - Pintus, Valentina
A1 - Prange, Michael
A1 - Spezzano, Pasquale
A1 - Varotsos, Costas
A1 - Verney-Carron, Aurélie
A1 - Vuorio, Tiina
A1 - Yates, Tim
T1 - Corrosion and Soiling in the 21st Century: Insights from ICP Materials and Impact on Cultural Heritage
N2 - This paper reviews results published by the International Co-operative Programme on Effects on Materials including Historic and Cultural Monuments (ICP Materials) with emphasis on those obtained after the turn of the century. Data from ICP Materials come from two main sources. The first is through exposures of materials and collection of environmental data in a network of atmospheric exposure test sites mainly distributed across Europe. Corrosion of carbon steel has continued to decrease during the period 2000–2020 but corrosion of zinc only up until 2014, and the trend in zinc corrosion is only visible when examining four-year data. Surface recession of limestone as well as soiling of modern glass show no decreasing trend during 2000–2020. The second is through case studies performed at heritage sites across Europe. Risk analysis of corrosion and soiling for twenty-six sites indicate that currently soiling is a more significant maintenance trigger than corrosion. Costs for maintaining heritage sites are substantial and costs attributable to air pollution is estimated from 40% to as much as 80% of the total cost. Future directions of the program are work on effects of particulate matter, improving the scientific basis for the work, and making the monitoring data publicly available.
KW - Corrosion
KW - Atmospheric corrosion
KW - Soiling
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644651
DO - https://doi.org/10.3390/cmd6040054
SN - 2624-5558
VL - 6
IS - 4
SP - 1
EP - 25
PB - MDPI AG
AN - OPUS4-64465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arai, Marylyn Setsuko
A1 - Machado, Thales Rafael
A1 - da Silva, Beatriz Giacomelli Rodrigues
A1 - Vilela, Raquel Riciati do Couto
A1 - de Camargo, Andrea Simone Stucchi
A1 - Zucolotto, Valtencir
T1 - Biomimetic Upconverting Nanoplatforms for Glioblastoma Bioimaging and Targeted Therapy
N2 - Infectious bacterial diseases, intensified by antibiotic resistance, cause millions of deaths annually and pose risks beyond human health, including water and food contamination. Current diagnostics are often slow, require complex equipment, and lack specificity, highlighting the need for rapid and reliable detection methods. To address this, we developed a luminescent sensor based on NaYF4 upconverting nanoparticles (UCNPs) doped with Er3+ or Tm3+, coated with COOH-PEG4-COOH, and functionalized with vancomycin (Van) or polymyxin-B (Poly) to selectively target Gram-positive and Gram-negative bacteria, respectively. Gold nanoparticles (AuNPs) served as quenchers, enabling a ratiometric “turn-on” mechanism: upon bacterial binding, the UCNP emission, initially quenched by AuNPs, was partially restored. This allowed differentiation through changes in the green/red (G/R) ratio for Er-UCNP@PEG4-Van and the blue/red (B/R) ratio for Tm-UCNP@PEG4-Poly. The sensor distinguished between Gram-positive and Gram-negative bacteria over a wide concentration range (0.05 to 5 × 105 CFU/mL) and showed high correlation with actual bacterial counts (r = 0.99 for S. aureus, r = 0.91 for E. coli). This platform is a potential fast, selective, and reliable tool for bacterial detection in clinical and environmental settings.
KW - Glioblastoma
KW - Homotypic targeting
KW - Cell membrane coating
KW - Upconverting nanoparticles
KW - Temozolamide
KW - Near infrared bioimaging
KW - Drug delivery
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652808
DO - https://doi.org/10.1021/acsanm.5c04567
SN - 2574-0970
VL - 10
IS - 39
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-65280
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klinge, A
A1 - Mönig, J
A1 - Ziegert, C
A1 - Richter, Matthias
A1 - Kalbe, Ute
A1 - Horn, Wolfgang
A1 - Röhlen, U
A1 - Rauscher, S
A1 - Roswag-Klinge, E
T1 - upMIN 100 – upcycling of mineral construction and demolition waste to substitute natural aggregates in earthen building materials
N2 - The construction sector is one of the most resource-intensive sectors in Germany and is responsible for 40 % of CO2 emissions. Around 517 million tons of mineral raw materials are required annually for the construction of buildings in Germany. At the same time, mineral construction waste was the largest material flow at 229.3 million tons (2020). The rates of construction and demolition waste (CDW) recycling have increased since 2000, especially for mineral waste. Nevertheless, the majority of recycled aggregates are used in technically largely unregulated applications (e.g. road construction). This downcycling leads to a loss of valuable resources for technically and economically valuable applications. The upMIN 100 research project is investigating the question of whether and to what extent recycled CDW is suitable as an additive an binder in earthen building materials. The focus is placed on grain sizes of < 2 mm, which are currently predominantly landfilled, as there are at present no regulations for their use in building products. The soil matrix of earthen building materials however, naturally contains of different grain sizes, whith < 2mm – 0,063 for aggregates and < 0.063 mm as a binder. Therefore, the focused grain sizes (sand, clay and silt) could have a high usage potential. In order to enable the use of CDW, the technical feasibility must be ensured, quality requirements for source materials (e.g. threshold values for pollutants in terms of health and environmental compatibility and hazardous substances) and permissible proportions of recycled aggregates must be defined. Two different building material developments (earth blocks and -plaster)were used to assess both, the technical feasibility as well the pollutant content of the recycled aggregate and its final emissions into the indoor air. For both materials two mixtures could be established, that also meet the mechanical specifications according to the DIN standard, such as the compressive strength. A method was developed to design material mixtures with a high amount of CDW that comply with the defined limit values. The mixtures reached a recycling rate of 28 % with high mechanical properties and 70 % with minimum strength requirements.
KW - Mineral waste
KW - Upcycling
KW - Earthen building product
KW - Circular construction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652831
DO - https://doi.org/10.1088/1755-1315/1554/1/012084
SN - 1755-1307
VL - 1554
IS - 1
SP - 1
EP - 9
PB - IOP Publishing
AN - OPUS4-65283
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hallier, Dorothea C.
A1 - Radnik, Jörg
A1 - Dietrich, Paul M.
A1 - Seitz, Harald
A1 - Hahn, Marc Benjamin
T1 - Radiation damage to amino acids, peptides and DNA-binding proteins: the influence of water directly monitored by X-ray photoelectron spectroscopy
N2 - Ionizing radiation damage to biomolecules plays a crucial role in radiotherapy as a cancer treatment. Among these, DNA-binding proteins are of particular interest due to their pivotal roles in shielding DNA and facilitating its repair. Hence, in this study, we present first-ever recorded data of radiation damage to a protein monitored directly with near-ambient pressure (NAP) X-ray photoelectron spectroscopy (XPS) under a water atmosphere. This surface sensitive technique was used to in situ damage and probe gene-V protein (G5P, a model DNA-binding protein) under wet NAP conditions and dry vacuum (UHV) conditions to determine the effect of water on the radiation response. In addition, the X-ray radiation damage to selected pure amino acids and short homopeptides was determined to better understand the variety of damage mechanisms within the complex protein. In dry samples, drastic chemical changes were detected in all biomolecules dominated by fragmentation processes. Here, the breakage of peptide
bonds in the peptides and the protein are dominant. Surprisingly, hydration – despite introducing additional indirect damage pathways via water radiolysis – led to a reduction in overall radiation damage. This behaviour was attributed to hydration-dependent changes in reaction rates and respective deexcitation and damaging channels within the molecules and secondary species such as low-energy (LEE), (pre)-hydrated/(pre)-solvated electrons and radical species such as hydroxyl radicals.
KW - Radiation damage
KW - (Near-ambient pressure) X-ray photoelectron spectroscopy
KW - Ultra-high vacuum
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647565
DO - https://doi.org/10.1039/d5cp01887k
VL - 27
IS - 48
SP - 1
EP - 22
PB - Royal Society of Chemistry
AN - OPUS4-64756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Cong
A1 - Aumont, Cédric
A1 - Mikhailova, Alina A.
A1 - Audisio, Tracy
A1 - Hellemans, Simon
A1 - Weng, Yi-Ming
A1 - He, Shulin
A1 - Clitheroe, Crystal
A1 - Wang, Zongqing
A1 - Haifig, Ives
A1 - Sillam-Dussès, David
A1 - Buček, Aleš
A1 - Tokuda, Gaku
A1 - Šobotník, Jan
A1 - Harrison, Mark C.
A1 - McMahon, Dino P.
A1 - Bourguignon, Thomas
T1 - Unravelling the evolution of wood-feeding in termites with 47 high-resolution genome assemblies
N2 - Termites are a lineage of social cockroaches abundant in tropical ecosystems where they are key decomposers of organic matter. Despite their ecological significance, only a handful of reference-quality termite genomes have been sequenced, which is insufficient to unravel the genetic mechanisms that have contributed to their ecological success. Here, we perform sequencing and hybrid assembly of 45 taxonomically and ecologically diverse termites and two cockroaches, resulting in haplotype-merged genome assemblies of 47 species, 22 of which were near-chromosome level. Next, we examine the link between termite dietary evolution and major genomic events. We find that Termitidae, which include ~80% of described termite species, have larger genomes with more genes and a higher proportion of transposons than other termites. Our analyses identify a gene number expansion early in the evolution of Termitidae, including an expansion of the repertoire of CAZymes, the genes involved in lignocellulose degradation. Notably, this expansion of genomes and gene repertoires coincided with the origin of soil-feeding in Termitidae and remained unchanged in lineages that secondarily reverted to a wood-based diet. Overall, our sequencing effort multiplies the number of available termite genomes by six and provides insights into the genome evolution of an ancient lineage of social insects.
KW - Comparative genomics
KW - Entomology
KW - Genome evolution
KW - Phylogenetics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651719
DO - https://doi.org/10.1038/s41467-025-65969-5
SN - 2041-1723
VL - 16
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amiri, Hesam
A1 - Nikookhesal, Aidin
A1 - Murugan, Divagar
A1 - Scholz, Stefan
A1 - Frentzen, Michael
A1 - Cao, Yuan
A1 - Nickl, Philip
A1 - Radnik, Jörg
A1 - Stockmann, Jörg M.
A1 - Vu, Xuan-Thang
A1 - Narayanan, Madaboosi S.
A1 - Knoch, Joachim
A1 - Ingebrandt, Sven
A1 - Adeli, Mohsen
A1 - Pachauri, Vivek
T1 - High precision correlative analysis of dielectric behavior evolution and anisotropy in graphene oxide thin film as a function of thermal annealing parameters
N2 - Graphene oxide (GO) and reduced graphene oxide (rGO) attract keen interest from different science and technology sectors owing to their tunable material characteristics dependent on C/O ratio. Thermal annealing in different gaseous environments serves as an effective approach to manipulate the C/O ratio in graphitic lattice, making it suitable for various electronic, optical and composites applications. Despite regular use of thermal annealing, systematic studies on dielectric properties evolution in GO against different annealing parameters remain elusive. This work reports on a reliable approach that adopts a joint Raman Spectroscopy, Mueller Matrix Spectroscopic Ellipsometry (MMSE) and high-precision electrical impedance spectroscopy (HP-EIS) framework for studying the evolution of dielectric behavior and anisotropies in GO. The experimental platform involved lithography-defined GO patterns connected to metal microelectrodes and glass passivation for protection from gaseous environments during annealing and measurements using Raman, MMSE and HP-EIS. The presented study delineates the effects of annealing parameters such as temperature, heating rate, and gaseous environment on GO permittivity. Novel findings include the discovery of a direct relationship between heating rate and dielectric properties, as well as determination of vertical limitation of MMSE for permittivity distribution characterization in GO, for the first time, to be around 8 nm.
KW - Thermal annealing
KW - Reduced graphene oxide
KW - Thin films
KW - 2D materials
KW - Spectroscopic ellipsometry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652428
DO - https://doi.org/10.1016/j.nwnano.2025.100130
SN - 2666-9781
VL - 11
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-65242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Rajotte, Isabelle
A1 - Thibeault, Marie-Pier
A1 - Sander, Philipp C.
A1 - Kodra, Oltion
A1 - Lopinski, Gregory
A1 - Radnik, Jörg
A1 - Johnston, Linda J.
A1 - Brinkmann, Andreas
A1 - Resch-Genger, Ute
T1 - Quantifying surface groups on aminated silica nanoparticles of different size, surface chemistry, and porosity with solution NMR, XPS, optical assays, and potentiometric titration
N2 - We assessed the quantification of surface amino functional groups (FGs) for a large set of commercial and custom-made aminated silica nanoparticles (SiO2 NPs) with sizes of 20–100 nm, prepared with different sol–gel routes, different amounts of surface amino FGs, and different porosity with four methods providing different, yet connected measurands in a bilateral study of two laboratories, BAM and NRC, with the overall aim to develop standardizable measurements for surface FG quantification. Special emphasis was dedicated to traceable quantitative magnetic resonance spectroscopy (qNMR) performed with dissolved SiO2 NPs. For the cost efficient and automatable screening of the amount of surface amino FGs done in a first step of this study, the optical fluorescamine assay and a potentiometric titration method were utilized by one partner, i.e., BAM, yielding the amount of primary amino FGs accessible for the reaction with a dye precursor and the total amount of (de)protonatable FGs. These measurements, which give estimates of the minimum and maximum number of surface amino FGs, laid the basis for quantifying the amount of amino silane molecules with chemo-selective qNMR with stepwise fine-tuned workflows, involving centrifugation, drying, weighting, dissolution, measurement, and data evaluation steps jointly performed by BAM and NRC. Data comparability and relative standard deviations (RSDs) obtained by both labs were used as quality measures for method optimization and as prerequisites to identify method-inherent limitations to be later considered for standardized measurement protocols. Additionally, the nitrogen (N) to silicon (Si) ratio in the near-surface region of the SiO2 NPs was determined by both labs using X-ray photoelectron spectroscopy (XPS), a well established surface sensitive analytical method increasingly utilized for microparticles and nano-objects which is currently also in the focus of international standardization activities. Overall, our results underline the importance of multi-method characterization studies for quantifying FGs on NMs involving at least two expert laboratories for effectively identifying sources of uncertainty, validating analytical methods, and deriving NM structure–property relationships.
KW - Advanced Materials
KW - Amino Groups
KW - Calibration
KW - Characterization
KW - Functional groups
KW - Method Comparison
KW - Nano Particle
KW - Validation
KW - XPS
KW - Optical Assay
KW - Quantification
KW - Surface Analysis
KW - Reference Materials
KW - Synthesis
KW - Fluorescence
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649992
DO - https://doi.org/10.1039/d5na00794a
VL - 7
IS - 21
SP - 6888
EP - 6900
PB - Royal Society of Chemistry
AN - OPUS4-64999
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schusterbauer, Robert
A1 - Schünemann, Pia
A1 - Nickl, Philip
A1 - Er, Jasmin
A1 - Kämmer, Victoria
A1 - Junge, Florian
A1 - Fazzani, Salim
A1 - Mrkwitschka, Paul
A1 - Meermann, Björn
A1 - Haag, Rainer
A1 - Donskyi, Ievgen
T1 - Bifunctional Reduced Graphene Oxide Derivatives for PFOA Adsorption
N2 - Innovative materials are crucial for removing persistent pollutants per‐ and polyfluorinated alkyl substances (PFAS) from water. Here, a novel bifunctional reduced graphene oxide (TRGO) adsorbent is developed and characterized by advanced surface sensitive methods. Compared to pristine TRGO, the functionalized TRGO shows markedly improved PFAS removal efficiency and demonstrates strong potential for water purification applications.
KW - Adsorber
KW - PFAS
KW - HR-CS-GFMAS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651238
DO - https://doi.org/10.1002/ceur.202500240
SN - 2751-4765
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-65123
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smerechuk, Anastasiia
A1 - Guilherme Buzanich, Ana
A1 - Büchner, Bernd
A1 - Wurmehl, Sabine
A1 - Morrow, Ryan
T1 - Synthesis and properties of Sr2La2NiW2O12, a new S = 1 triangular lattice magnet
N2 - Magnetic materials featuring triangular arrangements of spins are frequently investigated as platforms hosting magnetic frustration. Hexagonal perovskites with ordered vacancies serve as excellent candidates for two-dimensional triangular magnetism due to the considerable separation of the magnetic planes. In this work, the effects of chemical pressure on the ferromagnetic ground state of Ba2La2NiW2O12 by substitution of Ba2+ with Sr2+ to produce Sr2La2NiW2O12 are investigated. The two materials are characterized using synchrotron-based XRD, XANES and EXAFS in addition to magnetometry in order to correlate their crystal structures and magnetic properties. Both materials form in space group R 3, yet as a result of the enhanced bending of key bond angles due to the effects of chemical pressure, the T C value of the magnetic Ni2+ sublattice is reduced from ∼6 K in Ba2La2NiW2O12 to 4 K in Sr2La2NiW2O12.
KW - XRD
KW - Magnetic materials
KW - EXAFS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652982
DO - https://doi.org/10.1107/S2052520624007091
SN - 2052-5206
VL - 80
IS - 5
SP - 467
EP - 473
PB - International Union of Crystallography (IUCr)
AN - OPUS4-65298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wosniok, Aleksander
A1 - Schukar, Marcus
A1 - Breithaupt, Mathias
A1 - Kriegsmann, Andreas
T1 - Distributed Fibre Optic Monitoring of Hydrogen Storage Composite Pressure Vessels for Automotive Use
N2 - We present our research work on the condition monitoring of hydrogen storage composite pressure vessels using distributed fibre optic sensors. The sensing fibres are integrated into the composite structure by wrapping them over the polymer liner in the helical and circumferential direction during the manufacturing process of the carbon fibre reinforced polymer. The following use of optical backscatter reflectometry allows for continuous condition monitoring and precise detection and localization of structural damages during the entire service life. To account for the time-dependent strength degradation of the composite pressure vessels, both slow burst and ambient hydraulic cycling tests, respectively, were conducted on five 70 MPa pressure vessels with integrated fibre optic sensors. The results achieved via distributed fibre optic strain sensing demonstrate a near linear strain response to pressure suitable for sensitive condition monitoring and confirm the required robustness of the selected sensor solution.
T2 - DGZfP-Jahrestagung 2025
CY - Berlin, Germany
DA - 26.05.2025
KW - Distributed fibre optic sensor (DFOS)
KW - Composite pressure vessel
KW - Optical backscatter reflectometry
KW - Slow burst test
KW - Ambient hydraulic cycling test
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653067
DO - https://doi.org/10.58286/32344
SP - 1
EP - 8
PB - NDT.net
AN - OPUS4-65306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stohl, Leonie
A1 - Manninger, Tanja
A1 - Dehn, Frank
A1 - von Werder, Julia
T1 - Understanding bioreceptivity of concrete: material design and characterization
N2 - The climate crisis is driving an increasing demand for ecologically oriented concepts. In the building sector, this demand includes not only the use of environmentally friendly materials but also the greening of urban areas. One promising approach is the development of bioreceptive concrete façades, which support the growth of green biofilms directly on their surfaces. These innovative façades are anticipated to deliver benefits comparable to those of macroscopically greened façades, such as enhanced biodiversity and improved air quality, while offering the advantages of being more self-sustaining and stable systems once fully established.
However, the development of bioreceptive concrete presents substantial challenges. Due to the interdisciplinarity and novelty of this field, standardized methods for material characterization and bioreceptivity assessment are currently lacking. This study proposes an approach for evaluating surface properties crucial for bioreceptivity, developed on differently structured samples of ultra-high-performance concrete (UHPC). Existing methods and standards from concrete technology are critically reviewed and, where necessary, modified to meet the unique requirements of measuring bioreceptive material properties. Special attention is given to the surface pH value and water retention characteristics, as these are essential for promoting microbial growth and ensuring the long-term stability of green biofilms. The observed surface characteristics vary according to the imprinted surface structures, offering a spectrum of material properties and enabling the evaluation of their impact on bioreceptivity. The findings presented form the foundation for subsequent laboratory weathering experiments, which will be discussed in a complementary publication.
KW - Bioreceptivity
KW - Concrete
KW - Biofilm
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648180
DO - https://doi.org/10.1617/s11527-025-02863-y
SN - 1359-5997
VL - 58
IS - 10
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-64818
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Heideklang, René
A1 - Myrach, Philipp
A1 - Onel, Yener
A1 - Pelkner, Matthias
A1 - Pohl, Rainer
A1 - Stegemann, Robert
A1 - Ziegler, Mathias
A1 - Kreutzbruck, Marc
T1 - Vergleich konventioneller und neuer Oberflächenprüfverfahren für ferromagnetische Werkstoffe
N2 - Sicherheitsrelevante und zyklisch hoch belastete Bauteile erfordern zur Vermeidung von kostenintensiven Ausfällen besonders stabile Prozessparameter. Bereits sehr kleine Randzonenfehler können unter zyklischer Bauteilbelastung zu Risswachstum und letztendlich zum Bauteilversagen führen. Die frühzeitige Erkennung von Randzonenfehler in Hochleistungsbauteilen wie z.B. Zahnräder, Ritzelwellen und Kurbelwellen erfordert daher eine leistungsfähige zerstörungsfreie Oberflächenrissprüfung, die es ermöglicht in den hochbeanspruchten Funktionsflächen auch Härterisse, Schleifrisse oder Zundereinschlüsse zu detektieren.
Hierzu sind in den letzten Jahren einige neue, innovative Oberflächenprüfverfahren wie die laserangeregte Thermografie und die Streuflussprüfung mit hochauflösenden GMR-Sensoren oder magnetooptischen Verfahren entwickelt worden. Zusätzlich zur hohen Empfindlichkeit zeichnen sich diese innovativen Verfahren durch einen schnellen und teils auch berührungslosen Einsatz aus. Da die noch relativ neu-en Verfahren naturgemäß noch nicht normativ verankert sind, wurden auch bereits erste Validierungen durchgeführt. Um die Leistungsfähigkeit der Verfahren eingehend zu untersuchen, erfolgten Testreihen an verschiedenen Testkörpern in Bezug auf Ortsauflösung, Empfindlichkeit, Automatisierung und Bewertung der Messsig-nale.
Neben den neuen Verfahren und ihren ersten Schritten hin zur Validierung kamen als Referenz auch die „klassischen“ Verfahren der Magnetpulver- und Wirbelstromprüfung zum Einsatz, deren Leistungsfähigkeit durch angepasste Sondenentwicklung auch für sehr kleine Oberflächendefekte nochmals unter Beweis gestellt wurde. Zusätzlich wurde an einigen Testkörpern eine hochauflösende CT durchgeführt. Die Ergebnisse dieses Vergleiches werden vorgestellt und Möglichkeiten sowie Grenzen der einzelnen Verfahren herausgearbeitet.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
KW - Zerstörungsfreie Prüfung
KW - Oberflächenprüfung
KW - Vergleichskörper 1
KW - Sichtprüfung
KW - Magnetpulverprüfung
KW - Streuflussprüfung
KW - Farbeindringprüfung
KW - Wirbelstromprüfung
KW - Thermografie
KW - Radiografie
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344262
SN - 978-3-940283-68-9
IS - DGZfP BB 152
SP - Mi.2.B.4, 1
EP - 11
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-34426
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jonietz, Florian
A1 - Krankenhagen, Rainer
A1 - Noack, M.
A1 - Gensecke, K.
A1 - Wiedenmann, E.
T1 - 3D-Formbestimmung mit integrierter thermografischer Qualitätsprüfung
N2 - Sowohl die 3D-Formbestimmung als auch die Thermografie sind Verfahren der Qualitätssicherung. Im vorgestellten Projekt wird versucht, die beiden Methoden zusammenzuführen.
Das Prinzip des für die Formbestimmung verwendeten 3D-Scanners beruht auf dem bereits bekannten Verfahren der Streifenlichtprojektion. Die Neuartigkeit des hier verwendeten 3D-Scanners besteht darin, dass nicht im sichtbaren, sondern im infraroten Spektralbereich gearbeitet wird. Dadurch wird es möglich, nicht die Reflexion, sondern die Wärmestrahlung des Prüfobjektes nach Absorption der eingebrachten Strahlung auszuwerten. Dies ermöglicht, auch optisch „nicht-kooperative“ Oberflächen zu erfassen. Die Anregung mit Wärmestrahlung stellt das Bindeglied zum Verfahren der aktiven Thermografie für die Detektion verdeckter Schäden dar. Bei letzterem Verfahren wird der Wärmestau über Defekten beim Eindringen der Wärme in die Tiefe des Materials gemessen. Dabei stellen Defekte eine Störung des 3D-Scan-Verfahrens dar, während umgekehrt unregelmäßig geformte Oberflächen das thermografische Verfahren erschweren, d.h. der Messeffekt eines der Verfahren ist ein Störeffekt für das jeweils andere Verfahren.
Es wird zum einen der Frage nachgegangen, inwieweit das 3D-Scan-Verfahren durch verdeckte thermische Defekte beeinträchtigt wird, und zum anderen die Möglichkeit untersucht, den vorhandenen 3D-Scanner auch für die aktive Thermografie einzusetzen. Es werden CFK-Proben mit künstlich eingebrachten thermischen Defekten untersucht und die Möglichkeiten und Grenzen der vorhandenen Messapparatur für die Defekterkennung aufgezeigt.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - 3D-Formbestimmung
KW - Thermografische Qualitätsprüfung
KW - Streifenlichtprojektion
KW - 3D-Scanner
KW - Aktive Thermografie
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-407856
UR - https://jahrestagung.dgzfp.de/Portals/151//doc/Mi.1.A.3.pdf
SN - 978-3-940283-85-6
VL - 162
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-40785
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mooshofer, H.
A1 - Boehm, Rainer
A1 - Heinrich, W.
A1 - Fendt, K.
A1 - Goldammer, M.
A1 - Kolk, K.
A1 - Vrana, J.
T1 - Amplitudenbasierte Fehlergrößenbewertung mit SAFT: Auf dem Weg von der bildlichen Darstellung zum Messverfahren
N2 - Die Größenbewertung von Anzeigen und die Bestimmung der Nachweisgrenze spielen bei der Ultraschallprüfung eine zentrale Rolle: Sie stellen sicher, dass kritische Ungänzen erfasst und bruchmechanisch behandelt werden können.
Bei SAFT wurde bisher die Größe von Ungänzen dadurch bestimmt, dass die räumliche Anzeigenausdehnung im Rekonstruktionsergebnis ausgewertet wird, d.h. die Anzahl von Voxel über die sich eine Anzeige erstreckt. Auf diese Weise lassen sich jedoch nur Defektanzeigen bewerten, die größer oder gleich der Wellenlänge sind. Bei kleinen Defekten versagt diese Methode, d.h. es ist keine Größenbewertung möglich. Außerdem bietet diese Methode keine Aussage über die Nachweisgrenze des Verfahrens.
Ein Hauptvorteil von SAFT gegenüber der konventionellen Ultraschallprüfung ist aber gerade die Verbesserung der Nachweisgrenze, denn SAFT steigert das Signal-Rausch-Verhältnis (SNR) gegenüber dem Gefügerauschen und reduziert statistisches Rauschen. Um diesen Hauptvorteil nutzen (und quantifizieren) zu können, wird für SAFT eine Methode zur Nachweisgrenzenbestimmung und zur Größenbewertung der Anzeigen kleiner Ungänzen benötigt.
Neben ihrer räumlichen Ausdehnung lassen sich Anzeigen im SAFT-Ergebnis auch durch ihre Amplitude charakterisieren, wenn die Prüfkopfeigenschaften und die geometrischen Verhältnisse beim Scan berücksichtigt werden. Genauer gesagt durch die Amplitudensumme, in die - neben der Echoamplitude - auch die winkelabhängige Streucharakteristik eingeht.
Im Folgenden wird dargelegt, dass sich die Amplitudensumme zur Nachweisgrenzenbestimmung und zur Größenbewertung kleiner Ungänzen eignet.
Es wird der Zusammenhang zwischen der Amplitudensumme und der Größe von Ungänzen dargestellt, und es wird gezeigt, dass auch die Anzeigenposition und die Form des Prüfobjektes eine Rolle spielen können. Auf dieser Basis wird eine Methode zur Größenbestimmung kleiner Anzeigen im SAFT-Ergebnis entwickelt.
Damit lässt sich das SAFT-Ergebnis als Ersatzfehlergröße darstellen, so wie das bei konventioneller Ultraschallprüfung z.B. mit Hilfe von AVG-Diagrammen erfolgt.
Durch die Vervollständigung um die Größenbewertung ist SAFT nicht mehr nur ein bildgebendes Verfahren, sondern es kann vielmehr als vollwertiges Messverfahren dienen.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Synthetic aperture focussing technique (SAFT)
KW - Defektgrößenbewertung
KW - Gewichtete Amplitudensumme
KW - Kleine Reflektoren
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411571
SN - 978-3-940283-85-6
VL - 162
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-41157
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pelkner, Matthias
A1 - Pohl, Rainer
A1 - Erthner, Thomas
A1 - Stegemann, Robert
A1 - Kreutzbruck, Marc
A1 - Sergeeva-Chollet, N.
T1 - Eddy current testing with high-spatial resolution probes using MR arrays as receiver
N2 - Magneto-resistive (MR) sensor arrays are suited for high resolution eddy current testing (ET) of aerospace components due to two significant advantages compared to conventional coil systems. First, to obtain high spatial resolution they can be manufactured down to the µm-regime without losing their outstanding field sensitivity. Secondly, MR technology has a relatively frequency-independent sensitivity in the range of common ET-frequencies thus providing a benefit for low frequency applications.
This paper presents measurements using MR array probes consisting of 32 TMR-elements (tunnel magneto resistance), an ASIC, and subsequent readout components. A source for generating the eddy currents inside the material under test is also implemented onboard of the PCB. These probes were developed in the IMAGIC-project* for detection and imaging of surface breaking defects.
The performance of the new sensor system has been investigated for several mock-ups, Aluminum and Titanium plate specimens having small adjacent boreholes with diameter of 0.44 mm and micro notches in the µm-range, respectively. To compare our results we used conventional eddy current probes. The MR sensor elements have a length of around 60 µm leading to a nearly 'point like' measurement. Neighbouring boreholes (depth 0.25 mm) with a separation of 0.6 mm between their centres could be resolved with a good SNR, and more important, the boreholes could be confidently distinguished using the TMR-probes. In case of conventional probes a reliable separation was not possible. In this paper we present the MR-ET-probes of the IMAGIC consortium and a comparison with conventional techniques.
*The IMAGIC-project ('Integrated Magnetic imagery based on spIntronics Components', 2011 – 2014, project reference: 288381) was funded by the European Commission, Seventh Framework Programme. Further partners involved in the consortium beside BAM and CEA were INESC-ID and INESC-MN (Portugal), Sensitec GmbH (Germany), Tecnatom S.A. (Spain), and Airbus Group (France).
T2 - 7th International symposium on NDT in aerospace
CY - Bremen, Germany
DA - 16.11.2015
KW - TMR
KW - GMR
KW - Sensor array
KW - Eddy current testing (ET)
KW - Aerospace
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344254
SN - 978-3-940283-76-4
N1 - Serientitel: DGZfP-Proceedings – Series title: DGZfP-Proceedings
IS - DGZfP-BB 156
SP - We.5.A.4, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.v. (DGZfP)
AN - OPUS4-34425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Krankenhagen, Rainer
A1 - Röllig, Mathias
A1 - Hosseini, Seyed
A1 - Heckel, Thomas
A1 - Gaal, Mate
A1 - Schadow, Florian
A1 - Brackrock, Daniel
A1 - Gower, M.
A1 - Lodeiro, M.
A1 - Baker, G.
T1 - Quantitative Bewertung künstlicher und natürlicher Fehler in Faserverbundwerkstoffen mit aktiver Thermografie und Ultraschall
N2 - Im EMRP-Projekt VITCEA werden komplementäre ZFP-Verfahren zur Prüfung von Faserverbundwerkstoffen weiterentwickelt und validiert. In diesem Beitrag werden Ergebnisse verschiedener Techniken der aktiven Thermografie und des Ultraschalls vorgestellt. Die Nachweisempfindlichkeiten bezüglich künstlicher und natürlicher Fehler mit unterschiedlichen lateralen Ausdehnungen und in verschiedenen Tiefen werden miteinander verglichen.
T2 - DGZfP Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - CFK
KW - GFK
KW - Aktive Thermografie
KW - Phased Array Ultraschall
KW - Luftultraschall
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410902
SN - 978-3-940283-85-6
VL - BB 162
SP - Di1B1, 1
EP - Di1B1, 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e. V.
AN - OPUS4-41090
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maiwald, Michael
A1 - Gräßer, Patrick
A1 - Wander, Lukas
A1 - Zientek, Nicolai
A1 - Guhl, Svetlana
A1 - Meyer, Klas
A1 - Kern, Simon
T1 - Strangers in the Night—Smart Process Sensors in Our Current Automation Landscape
N2 - The departure from the current automation landscape to next generation automation concepts for the process industry has already begun. Smart functions of sensors simplify their use and enable plug-and-play integration, even though they may appear to be more complex at first sight. Smart sensors enable concepts like self-diagnostics, self-calibration, and self-configuration/parameterization whenever our current automation landscape allows it. Here we summarize the currently discussed general requirements for process sensors 4.0 and introduce a smart online NMR sensor module as example, which was developed for an intensified industrial process funded by the EU’s Horizon 2020 research and innovation programme (www.consens-spire.eu).
T2 - Eurosensors 2017 Conference
CY - Paris, France
DA - 03.09.2017
KW - Process Monitoring
KW - Smart Sensors
KW - CONSENS
KW - Online NMR Spectroscopy
KW - Mini-plant
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-415772
UR - http://www.mdpi.com/2504-3900/1/4/628
DO - https://doi.org/10.3390/proceedings1040628
VL - 1
SP - 628
EP - 631
PB - MDPI
CY - Basel
AN - OPUS4-41577
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Katsikini, M.
A1 - Pinakidou, F.
A1 - Paloura, E.C.
A1 - Arvanitidis, J.
A1 - Ves, S.
A1 - Reinholz, Uwe
A1 - Ppadomanolaki, E.
A1 - Iliopoulos, E.
T1 - Simulation of the EXAFS and Raman spectra of InxGa1-xN utilizing the equation of motion routine of FEFF8
N2 - A combined analysis of EXAFS and Raman spectra is applied for the study of
InxGa1-xN alloys with 0.3 0.5MeV) X-rays and proved the applicability of the present technique to inspect thick carbon-fiber laminated components. In order to improve the inspection time and image quality of the backscatter image, we used high-resolution (180ìm) digital detector arrays (DDAs). At the end, important applications of the presented X-ray backscatter technique to the aerospace industry are discussed.
T2 - ECNDT 2014 - 11th European conference on non-destructive testing
CY - Prague, Czech Republic
DA - 06.10.2014
KW - X-ray backscatter imaging
KW - Twisted-slit collimator
KW - NDT
KW - Digital detector array (DDA)
KW - Stringer
KW - Aerospace applications
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-322376
UR - https://www.ndt.net/?id=16431
SN - 1435-4934
VL - 19
IS - 12
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-32237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kind, Thomas
T1 - Ortung von Spanngliedern zum schadensfreien Bohren im Rahmen von Ertüchtigungsmaßnahmen
N2 - Am Beispiel der Ertüchtigung einer Brücke in Bremen wird gezeigt, wie mit den zerstörungsfreien Prüfverfahren (ZfP) Radar- und Ultraschall die genau Lage vorgespannte Bewehrung gefunden bzw. bestätigt werden kann. Im Rahmen von Ertüchtigungsmaßnahmen an Spannbetonbrücken werden häufig Kernbohrungen durchgeführt, die die vorhandenen Spannbewehrungen nicht beschädigen dürfen. Es wird die Vorgehensweise beschrieben, wie mit ZfP ein wesentlicher Beitrag geleistet wird, das Risiko einer Beschädigung zu minimieren und somit eine bessere Planungssicherheit für die Ertüchtigungsmaßnahmen zu schaffen. Dabei werden auch die Grenzen der beiden Verfahren aufgezeigt.
T2 - Fachtagung Bauwerksdiagnose 2012 - Praktische Anwendungen zerstörungsfreier Prüfungen und Zukunftsaufgaben
CY - Berlin, Germany
DA - 23.02.2012
KW - Radar
KW - Zerstörungsfreie Prüfung
KW - Stahlbeton
KW - Ultraschall
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-398225
SN - 978-3-940283-40-5
VL - 134 (Vortrag 11)
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin, Germany
AN - OPUS4-39822
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Ziegler, Mathias
A1 - Kunert, M.
A1 - Goldammer, M.
T1 - Entwicklung von Referenzprobekörpern für die Standardisierung der Blitzthermografie
N2 - Die aktive Thermografie wird in der Industrie zunehmend in verschiedenen Bereichen zur Qualitätssicherung, Zustandsdiagnose und Zustandsüberwachung eingesetzt. Bestehende Normen zur Thermografie beschreiben die Grundlagen, Geräte und Begriffe. In diesem Beitrag wird über ein Projekt berichtet, dessen Ziel die Erarbeitung einer Prüfnorm zur Blitzthermografie ist. Diese sollte neben der Auswahl geeigneter Gerätekomponenten, der Auswertungsverfahren und der Vorgehensweise bei der Prüfung auch die Beschreibung geeigneter Referenzprobekörper enthalten, die eine Bewertung der Messapparatur und eine Qualitätssicherung der Prüfung ermöglichen.
T2 - Thermographie-Kolloquium 2011
CY - Stuttgart, Germany
DA - 29.09.2011
KW - Aktive Thermografie
KW - Blitzanregung
KW - Prüfnorm
KW - Referenzprobekörper
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246230
SN - 978-3-940283-36-8
VL - 130
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-24623
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bartscher, M.
A1 - Ehrig, Karsten
A1 - Staude, Andreas
A1 - Goebbels, Jürgen
A1 - Neuschaefer-Rube, U.
T1 - Application of an industrial CT reference standard for cast freeform shaped workpieces
N2 - Industrial computed tomography (CT) today is an important method to analyze defects and to measure the geometry of technical products. The measurement capability of industrial CT often depends on the knowledge of the measurement errors being present. Only with this knowledge, effective corrections are possible by manufacturers, or adapted measurement procedures become possible for the customers. Thus, there is the strong need to have adequate reference standards both for the assessment of general dependencies and for the measurement of task-specific effects. Especially the latter are difficult to assess. This paper shows the application of a versatile dismountable workpiece-near reference body for the use with CT. The reference standard was made from a miniaturized cast aluminium (one-)cylinder head. It can be dismounted into four segments, each featuring reference geometries which enable a registration of CT measured and other reference datasets (e.g. from tactile CMM). The reference standard embodies complex freeform surfaces which are a challenging measurement task for CT and other sensors. Here the application of the reference standard is the study of the influence of material mixes. This is realized by adding pieces of other materials which disturb the mono-material measurement.
Results of the application of the reference standard are presented using data from industrial micro-CT systems and CMM reference data. A special emphasis is given on the workflow of the data processing and the data analysis.
T2 - International symposium on digital industrial radiology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Industrial reference standard
KW - Computed tomographie
KW - Freeform shaped workpieces
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-245532
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (We.4.3)
SP - 1
EP - 12
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Illerhaus, Bernhard
A1 - Badde, Aurelia
A1 - Michaelis, Matthias
A1 - Berger, U.
A1 - Onel, Yener
A1 - Meinel, Dietmar
A1 - Goebbels, Jürgen
T1 - Einsatz von mobilen Röntgenuntersuchungsmethoden im Museum - Zwei Fallbeispiele
N2 - Zwei Bildhauermodelle aus dem Georg-Kolbe-Museum Berlin standen zur Restaurierung an. Das kleinere, 'Lucino' (1920), 41cm, wurde hochauflösend mit CT gemessen, da mittels CT sowohl der Herstellungsprozeß einer Gipsstatue als auch der innere Zustand, wie Ergänzungen, Klebungen und Armierungen, festgestellt werden können. Aus den CT Bildern ergab sich eine für die vorher vermutete Gipszusammensetzung ungewöhnliche innere Struktur. Mit einer Freihand bedienten Röntgenpistole zur Messung der Röntgenfluoreszenz wurde daraufhin die Zusammensetzung des Materials der Statuette als Terracotta bestimmt. Durch den Einsatz von Helium als Spülmittel konnten auch leichte Materialien nachgewiesen und so eine Unterscheidung zwischen Gips und gebranntem Ton durchgeführt werden. Aus den CT Daten wurde eine virtuelle Darstellung der äußeren Geometrie gewonnen. Ein damit versuchsweise erstelltes Replik (Rapid Prototyping, 3D-Drucker, TU-Berlin) entsprach nicht den Anforderungen des Museums zur Erstellung einer Gußform für eine Bronzekleinserie der Statuette.
Die zweite Statue, die 'Große Nacht' (1930) ist mit ihrer Größe von 2,12m und aufgrund des durch korrodierende Metallarmierung verursachten Schadensbildes nicht mehr transportfähig. Eine in-situ Untersuchung mit dem mobilen Tomographen, der in den 1980ern zur Untersuchung von Bäumen gebaut und jetzt mit einem modernen Flachdetektor und einer Röntgenröhre ausgestattet ist, wird vorgestellt. Die Möglichkeiten acder in-situ CT für große Skulpturen werden anhand der Ergebnisse diskutiert.
T2 - DGZfP-Jahrestagung 2010
CY - Erfurt, Deutschland
DA - 10.05.2010
KW - Mobile CT
KW - Mobile RFA
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246956
UR - https://www.ndt.net/?id=10149
SN - 978-3-940283-26-9
VL - 122
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-24695
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Dey, Anika
A1 - Casperson, Ralf
A1 - Pohl, Rainer
A1 - Thomas, Hans-Martin
T1 - Die Wirbelstromprüfung als Hilfsmittel für die Schieneninstandhaltung
N2 - Die zerstörungsfreie Oberflächenprüfung an verlegten Eisenbahnschienen mit Wirbelstrom hat in den letzten Jahren durch ständige Weiterentwicklung und Verifizierung enorm an Bedeutung gewonnen. Es wurde u.a. angestrebt zuverlässige Planungsgrößen für den Einsatz von Instandhaltungsmaßnahmen zu erhalten, durch deren gezielten Einsatz Risswachstum unterbunden werden kann. Die Ursache für das Wachstum von Rissen in der Schiene liegt in der Materialermüdung des Werkstoffes infolge der Betriebsbelastungen im RadSchiene-Kontakt. Nach einer gewissen Beanspruchungsdauer kommt es an den Kontaktflächen der Fahrkante zu einer Kaltverfestigung des Schienenstahls. Durch fortschreitende Verfestigung des kontaktbeanspruchten Oberflächenbereichs der gehärteten Schicht wird der Werkstoff spröde und es bilden sich feine Risse aus. Die Risse wachsen anfangs unter einem flachen Winkel in das Schieneninnere hinein, neigen dann aber ab einem gewissen Stadium dazu in das Innere des Schienenkopfes abzukippen, was im Extremfall zu einem Schienenbruch führen kann. Diese Rollkontaktermüdungsrisse, auch genannt Head Checks, entstehen bevorzugt in der Fahrkante von bogenäußeren Schienen. Die Anwendung der Wirbelstromprüfung an der Schiene wurde bisher zur Ermittlung der Schädigungstiefe dieser Rollkontaktermüdungsrisse eingesetzt. Das Wirbelstromverfahren besitzt die Eigenschaft, sehr empfindlich auf alle Veränderungen der Materialeigenschaften an der Oberfläche zu reagieren. Daher wurde festgestellt, dass sich neben der Detektion von Rissen auch Fehler wie Eindrückungen oder Schlupfwellen, bis hin zu Materialveränderungen durch Schweißen oder Aufhärtungen in der Schienenoberfläche bestimmen lassen. Die Wirbelstromprüfung besitzt daher das Potenzial, mögliche Orte der Entstehung von Ermüdungsrissen in einem extrem frühzeitigen Stadium nachzuweisen. Ziel ist es, die rissgefährdeten Zonen schon im Zustand der Kaltverfestigung zu identifizieren. Dadurch können sich neue Aspekte für die präventive Schieneninstandhaltung ergeben.
T2 - DGZfP-Jahrestagung 2010 - Zerstörungsfreie Materialprüfung ZfP in Forschung, Entwicklung und Anwendung
CY - Erfurt, Germany
DA - 10.05.2010
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-214813
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-21481
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ehrig, Karsten
A1 - Goebbels, Jürgen
A1 - Meinel, Dietmar
A1 - Paetsch, O.
A1 - Prohaska, S.
A1 - Zobel, Valentin
T1 - Comparison of crack detection methods for analyzing damage processes in concrete with computed tomography
N2 - Analyzing damages at concrete structures due to physical, chemical, and mechanical exposures need the application of innovative non-destructive testing methods that are able to trace spatial changes of microstructures. Here, the utility of three different crack detection methods for the analysis of computed tomograms of various cementitious building materials is evaluated. Due to the lack of reference samples and standardized image quality evaluation procedures, the results are compared with manually segmented reference data sets. A specific question is how automatic crack detection can be used for the quantitative characterization of damage processes, such as crack length and volume. The crack detection methods have been integrated into a scientific visualization system that allows displaying the tomography images as well as presenting the results.
T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Crack detection
KW - Computed tomography
KW - Data visualization
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243569
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (Poster 2)
SP - 1
EP - 8
PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24356
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Duffner, Eric
A1 - Gregor, Christian
A1 - Bohse, Jürgen
T1 - Überwachung der Fertigungsqualität von Faserverbund - Druckbehältern mittels Schallemissionsprüfung
N2 - Ziel der Untersuchung ist die Validierung einer Prüfmethodik zur Sicherung der Fertigungsqualität von Faserverbund – Druckbehältern unter realen Fertigungsbedingungen.
Das Verfahren basiert auf Merkmalen und zulässigen Grenzwerten, die aus Schallemissionsverläufen bei der Erstdruckprüfung abgeleitet werden.
Die Methodik konnte zuvor bereits erfolgreich an Faserverbund –
Druckbehältern mit metallischem Liner getestet und patentiert werden.
Mit den aktuellen Untersuchungen wurde die Möglichkeit des Erkennens von Fertigungsfehlern in Kohlenstofffaser/Glasfaser – Hybriddruckbehältern mit polymerem Liner evaluiert.
Dazu wurden Faserverbund – Druckbehälter mittels Schallemissionsmessung bei einer hydraulischen Erstdruckprüfung überwacht, wie sie (ohne Schallemissionsprüfung) generell zur Qualitätssicherung nach der Fertigung von Faserverbund – Druckbehältern gefordert wird.
An Druckbehältern aus einer Serienproduktion wurden die Schallemissionsverläufe registriert und die mittleren Merkmalswerte sowie deren Streuung als Referenz ermittelt. Diese werden mit den Schallemissionsverläufen von Druckbehältern mit gezielt eingebrachten Fertigungsfehlern verglichen.
Bei den Fertigungsfehlern handelt es sich um Fehler, die in der Serienproduktion auftreten können und mit den Methoden der herkömmlichen Qualitätssicherung schwer oder gar nicht nachzuweisen sind.
Alle untersuchten Druckbehälter wurden im Anschluss an die Erstdruckprüfung auf verschiedene Weise bis zum Versagen (Leckage, Bersten) beansprucht. Damit war es möglich, den tatsächlichen Einfluss der Fertigungsfehler auf den Berstdruck bzw. das Ermüdungsverhalten der Behälter zu verifizieren und die Aussagefähigkeit des Schallemissionsverfahrens zu beurteilen.
T2 - 18. Kolloquium Schallemission
CY - Wetzlar, Germany
DA - 27.10.2011
KW - Faserverbund-Druckbehälter
KW - Schallemissionsprüfung
KW - Fertigungsüberwachung
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-247881
SN - 978-3-940283-37-5
IS - DGZfP-BB 131 (Vortrag 16)
SP - 1
EP - 9
AN - OPUS4-24788
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gaal, Mate
A1 - Caldeira, Rui
A1 - Bartusch, Jürgen
A1 - Kupnik, M.
T1 - Air-coupled ultrasonic ferroelectret receiver with additional DC voltage
N2 - Highly sensitive air-coupled ultrasonic sensors are essential for various applications such as testing of composite materials. One of the major challenges for the development of air-coupled ultrasonic sensors is the impedance matching to air. With a lower acoustic impedance than the usual piezoelectric materials, charged cellular polypropylene film (cPP) offers better matching to air with a similar piezoelectric coefficient. The piezoelectric behaviour demonstrated by cPP comes from polarized air cells that create a permanent internal voltage. The sensitivity of the sensor varies with the application of an additional DC bias voltage. Thus, this work presents a cPP ultrasonic sensor with an improvement of up to 15 ± 1 dB on the signal-to-noise ratio.
T2 - Eurosensors 2017
CY - Paris, France
DA - 3.9.2017
KW - Ultrasonic
KW - Air-coupled
KW - Cellular polypropylene
KW - Transducer
KW - Ferroelectret
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419009
DO - https://doi.org/10.3390/proceedings1040362
VL - 1
IS - 4
SP - Article 362, 1
EP - 4
AN - OPUS4-41900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wachsmuth, Janne
T1 - Wellenform basierte Quellenlokalisierung im Vergleich zu konventionellen Methoden
N2 - Für eine 10 mm dicke Stahlplatte kann ein Bandpass so gesetzt werden, dass alle vorhandenen Wellenmoden mit derselben Schallgeschwindigkeit eintreffen. Anhand von Ortungsabweichungen und Ortungsunsicherheitswerten kann gezeigt werden, dass im Vergleich zu herkömmlichen Methoden der Quellenortung die Ortungsgenauigkeit durch eine Frequenzfilterung verbessert werden kann.
T2 - 18. Kolloquium Schallemission
CY - Wetzlar, Deutschland
DA - 27.10.2011
KW - Schallemissionsprüfung
KW - Ermüdungsrisswachstum
KW - Korrosion
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-246612
SN - 978-3-940283-37-5
SP - 1
EP - 6
PB - DGZfP-BB 131
AN - OPUS4-24661
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Jaenisch, Gerd-Rüdiger
A1 - Kolkoori, Sanjeevareddy
A1 - Bellon, Carsten
T1 - Quantitative simulation of back scatter X-ray imaging and comparison to experiments
N2 - X-ray backscatter imaging is a well established NDT technique to inspect complex objects using only a single-sided access. In difference to conventional transmission X-ray radiography, the X-ray backscatter imaging utilizes the scattered radiation caused by the Compton scattering effect. In order to achieve high backscatter intensities from a test object, it is necessary to optimize the backscatter system parameters namely the angle between source and slit camera, the slit collimator system, the shielding between source and scatter camera, and the type of detector. In addition, the scatter phenomena in to the investigated object need to be understood.
In this contribution, we present a Monte Carlo model McRay which considers all relevant single and multiple interactions of photons and electrons. This model can be used to simulate back scatter techniques. It allows not only calculating the scatter image for a given experimental setup but also registering the spectrum of the detected scattered photons. Both aspects are important to understand the imaging process, to interpret the results, and to optimize the backscatter camera investigated here. Additionally experimental results will be presented and compared with simulations.
T2 - 19th World Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Radiology
KW - Back-scatter techniques
KW - Simulation
KW - Monte Carlo methods
KW - Measurements
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365897
SN - 978-3-940283-78-8
VL - 158
SP - 1
EP - 11
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin, Germany
AN - OPUS4-36589
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishra, Kirti Bhushan
A1 - Wehrstedt, Klaus-Dieter
A1 - Krebs, Holger
T1 - Boiling liquid expanding vapour explosion (BLEVE) of peroxy-fuels: Experiments and computational fluid dynamics (CFD) simulation
N2 - Fire and explosion hazards associated with storage and transportation of flammable materials have been a matter of great interest in the recent times. BLEVE is a scenario that occurs when a closed fuel container is subjected to heat for a longer duration. Such events are disastrous to human beings and assets both. In the past there have been numerous studies on BLEVEs and fireballs of hydrocarbon fuels, e.g. kerosene, gasoline, LPG, LNG and others. Though, the fireballs of peroxy-fuels are not looked into detail as such. This article tries to overcome this lack of knowledge. Both, experimental investigation and CFD simulations are performed to measure and predict the fireball characteristics of a peroxy-fuel. Due to thermal decomposition in the liquid phase and active oxygen content a peroxy-fuel fireball burns at a very fast rate and emit higher thermal radiation whereas exhibits smaller diameter and elevation compared to hydrocarbons. That eventually leads to consideration of larger safety distances from them which are also verified by CFD results.
KW - BLEVE
KW - Hydrocarbons
KW - Peroxy-fuels
KW - Safety distances
KW - CFD simulation
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334184
DO - https://doi.org/10.1016/j.egypro.2015.02.082
SN - 1876-6102
VL - 66
SP - 149
EP - 152
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-33418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kraehnert, R.
A1 - Ortel, Erik
A1 - Paul, B.
A1 - Eckhardt, B.
A1 - Kanis, M.
A1 - Liu, R.
A1 - Antoniou, A.
T1 - Electrochemically dealloyed platinum with hierarchical pore structure as highly active catalytic coating
N2 - Micro structured reactors are attractive candidates for further process intensification in heterogeneous catalysis. However, they require catalytic coatings with significantly improved space-time yields compared to traditional supported catalysts. We report the facile synthesis of homogeneous nanocrystalline Pt coatings with hierarchical pore structure by electrochemical dealloying of amorphous sputter-deposited platinum silicide layers. Thickness, porosity and surface composition of the catalysts can be controlled by the dealloying procedure. XPS analysis indicates that the catalyst surface is primarily composed of metallic Pt. Catalytic tests in gas-phase hydrogenation of butadiene reveal the typical activity, selectivity and activation energy of nanocrystalline platinum. However, space time yields are about 13 to 200 times higher than values reported for Pt-based catalysts in literature. The highly open metallic pore structure prevents heat and mass transport limitations allowing for very fast reactions and reasonable stability at elevated temperatures.
KW - Pt catalysts
KW - Pt–Si layers
KW - Scanning Electron Microscopy (SEM)
KW - Transmission Electron Microscopy (TEM)
KW - pore structure
KW - electrochemical dealloying
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351393
DO - https://doi.org/10.1039/C4CY00851K
SN - 2044-4753
SN - 2044-4761
VL - 5
IS - 1
SP - 206
EP - 216
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-35139
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hemmann, Felix
A1 - Agirrezabal-Telleria, Iker
A1 - Jäger, Christian
A1 - Kemnitz, E.
T1 - Quantification of acidic sites of nanoscopic hydroxylated magnesium fluorides by FTIR and 15N MAS NMR spectroscopy
N2 - Lewis and Brønsted sites were quantified in a series of weak acidic hydroxylated magnesium fluorides by Fourier transform infrared spectroscopy (FTIR) and solid state nuclear magnetic resonance spectroscopy (NMR) with pyridine as probe molecule. Molar extinction coefficients, which are necessary for quantitative FTIR measurements, were calculated by an easy approach. It utilizes the fact that both signals, used for the quantification by FTIR, are caused by the same deformation vibration mode of pyridine. Comparison of quantitative FTIR experiments and quantification by NMR shows that concentrations of acidic sites determined by FTIR spectroscopy have to be interpreted with caution. Furthermore, it is shown that the transfer of molar extinction coefficients from one catalyst to another may lead to wrong results. Molar extinction coefficients and concentrations of acidic sites determined by FTIR spectroscopy are affected by grinding and probably the particle size of the sample. High temperature during FTIR experiments has further impact on the quantification results.
KW - Acidity
KW - Fluoride catalyst
KW - Infrared spectroscopy
KW - Adsorption of pyridine
KW - Molar extinction coefficient determination
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351448
DO - https://doi.org/10.1039/C5RA15116C
SN - 2046-2069
VL - 5
IS - 109
SP - 89659
EP - 89668
PB - RSC Publishing
CY - London
AN - OPUS4-35144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bellon, Carsten
A1 - Gollwitzer, Christian
A1 - Fratzscher, Daniel
A1 - Ewert, Uwe
A1 - Jaenisch, Gerd-Rüdiger
T1 - Simulation of complex scan paths for 3D reconstruction
N2 - X-ray computed tomography (CT) is a volumetric (3D) Imaging diagnostic method, well established in the medical field, and in industrial NDE as well. Developments in industrial CT aim to extent the applicability to complex structures, which do not allow the access of all directions. This are e.g. limited view, data and angle CT applications. New reconstruction algorithms are required on one
side, and the accuracy has to be improved on the other side. Numerical Simulation can support such developments by providing well defined data sets for the testing of reconstruction algorithms. This approach of virtual CT is realized within the radiographic simulator aRTist, developed by BAM. The poster shows the possibilities of this tool to consider complex scan paths. Simulated data sets have been reconstructed by an versatile backprojection algorithm.
T2 - International symposium on digital industrial radiology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Radiographie
KW - Computer-Simulation
KW - 3D-Rekonstruktion
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243928
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (Poster 17)
SP - 1
EP - 4
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gollwitzer, Christian
A1 - Bellon, Carsten
A1 - Deresch, Andreas
A1 - Ewert, Uwe
A1 - Jaenisch, Gerd-Rüdiger
T1 - On POD estimations with radiographic simulator aRTist
N2 - The computer simulation of radiography is applicable for different purposes in NDT such as for the qualification of NDT systems, the optimization of system parameters, feasibility analysis, model-based data interpretation, education and training of NDT/NDE personnel, and others. Within the framework of the European project PICASSO simulators will be adapted to support reliability assessments of NDT tasks. The radiographic simulator aRTist developed by BAM is well suited for this task. It combines analytical modelling of the RT inspection process with the CAD-orientated object description applicable to various industrial sectors such as power generation, aerospace, railways and others. The analytic model includes the description of the radiation source, the interaction of Radiation
with the material of the part, and the detection process with special focus to DIR. To support reliability estimations the simulation tool is completed by a tool for probability of detection (POD) estimation. It consists of a user interface for planning automatic simulation runs with varying parameters, specifically defect variations.
Further, an automatic image analysis procedure is included to evaluate the defect visibility and calculate the POD therefrom.
T2 - International symposium on digital industrial radiology and computed tomography
CY - Berlin, Germany
DA - 20.06.2011
KW - Radiographie
KW - Computersimulation
KW - Probability of detection
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-245092
SN - 978-3-940283-34-4
IS - DGZfP-BB 128 (Tu.2.3)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-24509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Osterloh, Kurt
A1 - Bellon, Carsten
A1 - Hohendorf, Stefan
A1 - Kolkoori, Sanjeevareddy
A1 - Wrobel, Norma
A1 - Nusser, A.
A1 - Freitag, M.
A1 - Bücherl, T.
A1 - Bar, D.
A1 - Mor, I.
A1 - Tamin, N.
A1 - Weiss-Babai, R.
A1 - Bromberger, B.
A1 - Dangendorf, V.
A1 - Tittelmeier, K.
T1 - Computed tomography with X-rays and fast neutrons for restoration of wooden artwork
N2 - The objects of this investigation were sculptures taken from a ca. three hundred years old baroque epitaph of a church in Tonning, a town in Northern Germany. Around 1900 it was found in a disastrous state heavily damaged by wood-worm. At that time, the whole artwork was treated with the tar extract carbolineum as a remedy. Nowadays, this substance has been identified as carcinogenic, and its presence can be perceived by its stench and visually at certain spots on the surface where it has penetrated the covering paint.
A gold-painted sculpture of a massive wooden skull was interrogated with X-rays and fast neutrons to investigate the internal distribution of the carbolineum. The X-ray tomography, with its excellent spatial resolution revealed galleries left over from the worm infestation in the outer areas and cracks in the central region. The golden color coating appeared as a thick and dense layer. In comparison the tomography with fast neutrons, though being of lower resolution and yet unresolved artefacts revealed sections of slightly different densities in the bulk of the wood. These differences we attribute to the differences in the distribution of the impregnant in the wood, visible due to its higher hydrogen content making it less transparent for neutrons.
T2 - WCNR-10 - 10th World conference on neutron radiography
CY - Grindelwald, Switzerland
DA - 05.10.2014
KW - Computed tomography
KW - Neutron radiology
KW - Conservation of wooden artwork
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323050
DO - https://doi.org/10.1016/j.phpro.2015.07.066
SN - 1875-3892
VL - 69
SP - 472
EP - 477
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-32305
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dmitriev, A. I.
A1 - Österle, Werner
ED - Österle, Werner
ED - Zhang, G.
T1 - The role of solid lubricants for brake friction materials
N2 - This review article comprises of three parts. Firstly, reports of brake manufacturers on the beneficial impact of solid lubricants for pad formulations are surveyed. Secondly, since tribofilms were identified to play a crucial role in friction stabilization and wear reduction, the knowledge about tribofilm structures formed during automotive braking was reviewed comprehensively. Finally, a model for simulating the sliding behavior of tribofilms is suggested and a review on modelling efforts with different model structures related to real tribofilms will be presented. Although the variety of friction composites involved in commercial brake systems is very broad, striking similarities were observed in respect to tribofilm nanostructures. Thus a generalization of the tribofilm nanostructure is suggested and prerequisites for smooth sliding performance and minimal wear rates have been identified. A minimum of 13 vol.% of soft inclusions embedded in an iron oxide based tribofilm is crucial for obtaining the desired properties. As long as the solid lubricants or their reaction products are softer than magnetite, the main constituent of the tribofilm, the model predicts smooth sliding and a minimum of wear.
KW - Solid lubricant
KW - Friction
KW - Automotive braking
KW - Tribofilm
KW - Sliding simulation
KW - MCA-modeling
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355973
UR - www.mdpi.com/journal/lubricants
DO - https://doi.org/10.3390/lubricants4010005
SN - 2075-4442
VL - 4
IS - 1
SP - 5
EP - 26
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-35597
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krause, Martin
A1 - Effner, Ute
A1 - Müller, Sabine
A1 - Nowak, Thomas Rudolf
A1 - Vergin, Dirk
T1 - 3D-SAFT Imaging von Streuern in Brettschichtholz
N2 - Aktuell wird die Ultraschallechotechnik für Holzbauteile genutzt, indem aus der Abschattung eines ansonsten stabilen Rückwandechos auf Auffälligkeiten im Holzbauteil geschlossen wird. Dabei werden Transversalwellen (Mittenfrequenz 50 kHz) mit der Polarisationsrichtung in Faserrichtung (L) angewendet. In einem 2012 abgeschlossenen Forschungsvorhaben wurde nun die direkte Abbildung von Streuern durch anisotrope SAFT-Rekonstruktion entwickelt.
Dazu werden flächig aufgenommene Ultraschallmessdaten mit automatisiert scannenden Druck- und Scherwellenköpfen erzeugt und auf Basis anisotroper Geschwindigkeitsverteilungen rekonstruiert. Benutzt werden die auch häufig für Beton eingesetzten trocken ankoppelnden Punktkontakt-Prüfköpfe. Da damit auch intensive Wellen an der Oberfläche erzeugt werden, entstehen im Material zusätzliche Kopfwellen, die ebenfalls bei der Rekonstruktion berücksichtigt werden.
Da die Wellengeschwindigkeiten in Holz individuell stark schwanken, wird eine interaktive Auswertetechnik zur Ermittlung der Materialkonstanten benutzt. Für die Messungen werden Druckwellen sowie Scherwellen in zwei Polarisationsrichtungen verwendet. Die Messungen erfolgen sowohl mit automatischen Scannersystemen als
auch mit einem linearen Prüfkopf-Array (kommerziell erhältlicher multistatischer Messkopf). Gezeigt werden Ergebnisse an Bauteilen mit künstlichen und realen Fehlstellen. Das Forschungsprojekt wurde gefördert vom Bundesamt für Bau- und Raumordnung (BBR, Zukunft Bau).
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Holz
KW - Ultraschallecho
KW - Anisotropie
KW - Rekonstruktionsrechnung
KW - Fehlstellenortung
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-293509
SN - 978-3-940283-49-8
IS - Poster 8
SP - 1
EP - 9
AN - OPUS4-29350
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Krankenhagen, Rainer
A1 - Groll, E.T.
A1 - Kalisch, U.
A1 - Maierhofer, Christiane
A1 - Mecke, R.
A1 - Meinhardt, J.
A1 - Myrach, Philipp
A1 - Schiller, M.
A1 - Seidl, T.
T1 - Untersuchung der Putzritzungen am Magdeburger Dom mit aktiver Thermografie und optischen 3D-Messverfahren
N2 - Eines der bedeutendsten Kunstwerke des Magdeburger Doms sind die Putzritzungen am Ostflügel des Kreuzgangs aus dem 13. Jahrhundert. Der größte Teil der einzelnen Putzoberflächen sind Ausbesserungen oder Neuverputzungen aus verschiedenen Restaurierungs- oder Reparaturphasen. In dem von der Forschungsinitiative Zukunft Bau geförderten Projekt zur 3D-Kartierung von Bauwerksoberflächen wurden Untersuchungen zur Erfassung der Schäden an diesen Putzritzungen mit optischen 3D-Messverfahren und der aktiven Thermografie durchgeführt. Dabei wurden bei den optischen Verfahren hochauflösende Techniken zur Erfassung der Oberflächentopologie (Stereophotogrammmetrie) und zur Vermessung der Rissstrukturen und Ausbeulungen (3D-Trackingverfahren) eingesetzt. Die Zuordnung der Signaturen in den Thermogrammen zu Hohlstellen sowie Materialergänzungen und -ersatz wird diskutiert. Weiterhin erfolgt ein Vergleich der Ergebnisse mit Messungen an neu freigelegten Putzbereichen.
T2 - Thermographie-Kolloquium 2013
CY - Leinfelden-Echterdingen, Germany
DA - 26.09.2013
KW - Aktive Thermografie
KW - Stereophotogrammetrie
KW - Trackingsystem
KW - Risse
KW - Putz
KW - Mauerwerk
KW - Denkmalpflege
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-293987
SN - 978-3-940283-52-8
IS - DGZfP-BB 143 (Vortrag 6)
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-29398
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maierhofer, Christiane
A1 - Myrach, Philipp
A1 - Steinfurth, Henrik
T1 - Einfluss von Material, Messparametern und Umgebungsbedingungen auf die Nachweisempfindlichkeit der Blitzthermografie
N2 - Dieser Beitrag fasst die Untersuchungsergebnisse zu den Verfahrensgrenzen der Blitzthermografie zur Ortung und Charakterisierung von Fehlstellen in Metallen zusammen. Regeln zur Abschätzung von Eindringtiefe und Tiefenauflösung werden vorgestellt und überprüft. Weiterhin werden Vorgehensweisen zur Optimierung des Intensitätskontrastes von Fehlstellenanzeigen vorgestellt.
Einfache analytische Abschätzungen werden durch eine Vielzahl von experimentellen Untersuchungen an Kupfer- und Stahl-Probekörpern ergänzt. Dabei wurden sowohl die Parameter der Blitzlichtanregung als auch der Messwerterfassung umfassend variiert.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-285733
SN - 978-3-940283-49-8
IS - Di.2.A.1
SP - 1
EP - 8
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28573
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Boehm, Rainer
A1 - Brackrock, Daniel
A1 - Montag, Hans-Joachim
A1 - Brekow, Gerhard
T1 - Matrixarrays zur bildgebenden Ultraschallprüfung am Beispiel 6 mm dicker CFK-Platten
N2 - Faserverbundwerkstoffe wie kohlefaserverstärkte Kunststoffe CFK sind vergleichsweise schwer mit Ultraschall zu prüfen, weil die starke Dämpfung, der inhomogene Aufbau und die akustische Anisotropie die Wellenausbreitung behindern bzw. komplizieren. Die Folge ist, dass die Ansprüche an die Prüfung oft stark reduziert werden müssen. Die vorgestellte Prüftechnik nutzt die Möglichkeiten der räumlichen Fokussierung und des zweidimensionalen Winkelscans von Matrix Phased Array Prüfköpfen MPA in Kombination mit Echosignalüberlagerungsalgorithmen für eine substantielle Verbesserung der Auflösung und des Signal-Rausch-Verhältnisses. Sowohl bei der Ansteuerung des MPA als auch bei der Auswertung wird die Anisotropie des Werkstoffs berücksichtigt. Das MPA wird über die Oberfläche bewegt und an einer Anzahl von Messpunkten werden zweidimensionale Winkelscans durchgeführt. Das Ergebnis sind räumliche Echohöhenverteilungen, aus denen Schnittbilder oder auch Volumendarstellungen erzeugt werden können.
Anhand von Messungen an CFK-Platten mit Flachbodenbohrungen KSR 1 und 2 sollen die Empfindlichkeit und das Auflösungsvermögen der Prüftechnik demonstriert werden. Weiterhin werden Untersuchungen an Impaktschäden gezeigt, die typischerweise bei Faserverbundwerkstoffen bei starken punktförmigen Belastungen auftreten.
T2 - DACH-Jahrestagung 2012
CY - Graz, Austria
DA - 17.09.2012
KW - Ultraschallprüfung
KW - Matrix phased array
KW - Bildgebung
KW - CFK
KW - Anisotropie
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-285729
SN - 978-3-940283-44-3
IS - DGZfP-BB 136
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28572
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kind, Thomas
A1 - Kurz, J.H.
A1 - Taffe, Alexander
A1 - Wöstmann, Jens
T1 - Ortung und Unterscheidung von Querspanngliedern hinter schlaffer Bewehrung mit dem Radarverfahren in einer Fahrbahnplatte
N2 - Anhand eines erfolgreichen Messeinsatzes an einer Spannbetonbrücke, deren Querspannglieder zuverlässig lokalisiert und nachfolgend instandgesetzt werden sollen, wird die Vorgehensweise der Radarmessung mit zwei verschiedenen Polarisationsrichtungen der Antenne zur Unterscheidung von unterschiedlichen Arten der Bewehrungen ausführlich erklärt. Das Radarverfahren eignet sich sehr gut für die zerstörungsfreie Ortung von Bewehrung in Stahlbetonbauwerken. Insbesondere lässt sich mit dem Verfahren vorgespannte Bewehrung bis in einer Tiefe von ca. 30 cm und bei einem normalen Bewehrungsgrad (Maschenweite >10 cm) der schlaffen Bewehrung zuverlässig auffinden. Seit einigen Jahren wird das Radarverfahren erfolgreich im Vorfeld einer schadensfreien Kernbohrung im Rahmen von Ertüchtigungsmaßnahmen von Stahlbetonbrücken mit externen Spanngliedern angewendet. Aufgrund der Lage und dem Verlauf der vorgespannten Bewehrung in Hohlkastenseitenwänden und Plattenbalken kann eine vorgespannte Bewehrung von schlaffer Bewehrung in diesen Bauwerken sehr gut unterschieden werden. Diese Unterscheidungsmerkmale lassen sich aber bei Querspanngliedern in einer Fahrbahnplatte nur selten anwenden, da häufig die Überdeckung und der Abstand der schlaffen Bewehrung und der Querspannglieder ähnlich sind. In diesem Beitrag wird beschrieben, wie der gezielte Einsatz verschiedener Polarisationsrichtungen der Antenne zu einer zuverlässigen Unterscheidung von schlaffer Bewehrung und Spanngliedern beiträgt und damit zu einer verbesserten bildgebenden Darstellung der inneren Konstruktion der Fahrbahnplatte führt.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
KW - Bauwesen
KW - Zerstörungsfreie Prüfung
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-294454
SN - 978-3-940283-49-8
IS - DGZfP-BB 141 (Mi.1.B.3)
SP - 1
EP - 9
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-29445
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Bischof, Eik
A1 - Taffe, A.
T1 - Multi-sensor investigation of concrete moisture using ultrasound, radar and microwave
N2 - Moisture and salt loads of concrete can significantly change its microstructure and consequently lead to chemical and mechanical degradation. However, the non-destructive investigation of moisture and salt present in concrete is still difficult. In order to address and compare the sensitivity of different methods concrete samples with different pore systems realized by varying the w/z ratios have been fabricated. The focus of this study was put on the analysis of ultrasonic long and trans waves measured on the surface and in transmission mode. The results show clear dependencies of all applied methods. With the radar and microwave methods predominantly changes in the concrete moisture could be detected, whereas the different pore systems were not observed to alter the signals. In contrast for the ultrasound method also the ongoing hydration as well as the nature of the pore system strongly influenced the signals. As a consequence in a subsequent drying experiment it was also tried to delineate the effects of moisture and hydration. All specimens have been re-saturated under pressure and the drying experiment was repeated using the same multi-sensor approach.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Concrete
KW - Moisture
KW - Non-destructive testing
KW - Ultrasound
KW - Radar
KW - Velocities
KW - Microwave
KW - Multi-sensor approach
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347612
UR - http://www.ndt.net/?id=18322
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kruschwitz, Sabine
A1 - Feldmann, Rüdiger
T1 - Comparison of non-destructive moisture measurement methods on cement and calcium sulphate based screed samples
N2 - Measuring the moisture content of floor screeds is usually done with minor destructive testing methods like Darr drying or the Calcium Carbid (CM) method. These require small samples, deliver only punctual information and still have proven not to be very reliable. Hence, a study has been made using the standard destructive tests as well as a suite of non-destructive testing methods working out their use for moisture determination. In this study five partners from research institutes and industry worked together and intensively researched different technologies. The main focus was put on the varying sensitivity of the measuring techniques in different moisture ranges. Especially for low moisture contents ( or ‘critical’ moisture contents when the screed is dry enough to be covered with the final floor finish), several commercial devices including the most commonly used CM-method failed to determine the correct moisture content for cementitious samples. Hence the need for more accurate, if possible non-destructive methods is high, taking also into account that the chemistry (and physical properties) of screeds may vary strongly depending on their origin and purpose.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Screed
KW - Moisture
KW - Non-destructive testing
KW - Radar
KW - Capacitive methods
KW - Resistivity
KW - Multi-sensor
KW - Electrics
KW - Monitoring
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347602
UR - http://www.ndt.net/?id=18368
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Beckmann, Jörg
A1 - Fratzscher, Daniel
A1 - von Chrzanowski, Lars
A1 - Ewert, Uwe
T1 - Zeitaufgelöste THz-Spektroskopie für technische und zivile Sicherheitsanwendungen
N2 - Vortrag über Zeitaufgelöste THz-Spektroskopie für technische und zivile Sicherheitsanwendungen
T2 - DACH-Jahrestagung 2012
CY - Graz, Austria
DA - 17.09.2012
KW - THz Spektroskopie
KW - Technische und zivile Sicherheit
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-280013
SN - 978-3-940283-44-3
IS - DGZfP-BB 136
SP - Mi.1.C.4, 1
EP - 14
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-28001
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fasano, A.
A1 - Woyessa, G.
A1 - Stajanca, Pavol
A1 - Markos, C.
A1 - Stefani, A.
A1 - Nielsen, K.
A1 - Rasmussen, H. K.
A1 - Krebber, Katerina
A1 - Bang, O.
T1 - Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors
N2 - Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C. We also characterize the mPOF optically and mechanically, and further test the sensitivity of the PC FBG to strain and temperature. We demonstrate that the PC FBG can bear temperatures as high as 125°C without malfunctioning. In contrast, polymethyl methacrylate-based FBG technology is generally limited to temperatures below 90°C.
KW - Fiber optics sensors
KW - Fiber Bragg gratings
KW - Microstructured fibers
KW - Fiber characterization
KW - Polymers
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355591
DO - https://doi.org/10.1364/OME.6.000649
SN - 2159-3930
VL - 6
IS - 2
SP - 649
EP - 659
PB - OSA Publishig
AN - OPUS4-35559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Niederleithinger, Ernst
T1 - Neue Ideen für die zerstörungsfreie Prüfung von Beton: Seismische Interferometrie und mehr
N2 - Ultraschallverfahren haben sich im Bauwesen in den letzten Jahren immer mehr in der Praxis etabliert. Echomessungen zur Geometriebestimmung sind Stand der Technik. In der Wissenschaft gibt es zahlreiche Ideen, die Messmethodik und die Auswertung weiter zu verbessern sowie den Einsatzbereich zu erweitern. Erste eingebettete Ultraschallsysteme zum Langzeitmonitoring sind installiert, Mehrkanalgeräte ermöglichen immer größere Aperturen und Eindringtiefen, verbesserte Abbildungsverfahren zeigen immer mehr Details. Zusätzlich lassen sich Verfahren aus der Geophysik adaptieren, die weiteren Fortschritt versprechen. Die Seismische Interferometrie dient klassisch dazu, Materialeigenschaften des Erduntergrundes mittels seismischer Wellen zu bestimmen. Derzeitige Anwendungsbereiche sind die Verbesserung seismischer Abbildungsverfahren, Interpolation seismischer Spuren (A-Scans), Bestimmung von Quellparametern oder die Eliminierung unerwünschter Signale in passiven und aktiven Experimenten, hauptsächlich durch Kreuzkorrelation und Bestimmung Greenscher Funktionen. Diese Techniken können auch auf Ultraschalldaten, die an Betonkonstruktionen erfasst wurden, angewendet werden. Moderne Abbildungsverfahren benötigen eine möglichst hohe A-Scan-Dichte und eine genaue Kenntnis des Quellsignals. Beides ist nicht unbedingt gegeben, z. B. wegen der physischen Größe der Sensoren und wechselnder Ankopplungsbedingungen. In simulierten und realen Experimenten wurden interferometrische Methoden zur Lösung dieser Aufgabenstellungen evaluiert. Es zeigt sich, dass fehlende A-Scans kinematisch korrekt interpoliert werden können, wenn ausreichend viele Sender- und Empfängerpositionen genutzt wurden. Amplituden und Signalform sind verändert, können aber durch adaptive Filterung angepasst werden. Die Quellsignalform kann mit hoher Genauigkeit rekonstruiert werden. Die Ergebnisse können potentiell zu einer Verbesserung der Abbildung des Inneren der untersuchten Objekte genutzt werden.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Zerstörungsfreie Prüfung
KW - Geophysik
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337967
UR - http://www.ndt.net/article/dgzfp2014/papers/di1c1.pdf
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Di.1.C.1, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-33796
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Wolf, Julia
A1 - Mielentz, Frank
A1 - Milmann, Boris
A1 - Wiggenhauser, Herbert
T1 - Grundlagenuntersuchungen von Ultraschall-Sensoren in Beton
N2 - Für Ultraschallmessungen in Betonbauteilen wurden neuartige radialsymmetrisch abstrahlende Longitudinalwellenprüfköpfe mit einer Mittenfrequenz von 60 kHz auf deren Eignung hinsichtlich Abstrahlcharakteristik, Empfindlichkeit und Frequenzspektrum untersucht.
Für die Messung der Abstrahlcharakteristiken wurden die Prüfköpfe vertikal und horizontal in Betonzylinder eingebettet und die Richtungsabhängigkeiten der Schallschnelle mithilfe eines Laservibrometers gemessen.
Die Streuung der Prüfkopfempfindlichkeit wurde im Wasserbad unter Verwendung verschiedener Köpfe gleicher Bauart bestimmt. Außer Änderungen der Signalamplituden zeigten sich auch Schwankungen im Frequenzbereich bei verschiedenen Sender-Empfängerkombinationen.
Die Schallschwächung des Betons hat Einfluss auf die erreichbare Auflösung der Messungen und damit auf die maximal möglichen Senderabstände im Bauteil. Durch experimentelle Untersuchungen und Simulationen erfolgte eine Optimierung der Abstände hinsichtlich des Aufwandes und der geforderten Auflösung. Die Signalschwächung im Beton wurde mit verschiedenen Impulsen im Frequenzbereich von 50 kHz bis 100 kHz in Abhängigkeit verschiedener Bewehrungsgrade und Korngrößen ermittelt. Hierfür wurden die Sensoren in unterschiedlichen Abständen in die Probekörper einbetoniert und die Empfangssignale hinsichtlich Amplitudenabfall und Frequenzspektrum untersucht.
T2 - DGZfP-Jahrestagung 2013
CY - Dresden, Germany
DA - 06.05.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-294153
SN - 978-3-940283-49-8
IS - DGZfP-BB 141 (Poster 56)
SP - 1
EP - 9
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V. (DGZfP)
AN - OPUS4-29415
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, Martin
A1 - Mauke, R.
A1 - Effner, Ute
A1 - Milmann, Boris
A1 - Völker, Christoph
A1 - Wiggenhauser, Herbert
T1 - Ultrasonic testing of a sealing construction made of salt concrete in an underground disposal facility for radioactive waste
N2 - For the closure of radioactive waste disposal facilities engineered barriers- so called “drift seals” are used. The purpose of these barriers is to constrain the possible infiltration of brine and to prevent the migration of radionuclides into the biosphere. In a rock salt mine a large scale in-situ experiment of a sealing construction made of salt concrete was set up to prove the technical feasibility and operability of such barriers. In order to investigate the integrity of this structure, non-destructive ultrasonic measurements were carried out.
Therefore two different methods were applied at the front side of the test-barrier:
1 Reflection measurements from boreholes
2 Ultrasonic imaging by means of scanning ultrasonic echo methods This extended abstract is a short version of an article to be published in a special edition of ASCE Journal that will briefly describe the sealing construction, the application of the non-destructive ultrasonic measurement methods and their adaptation to the onsite conditions -as well as parts of the obtained results. From this a concept for the systematic investigation of possible contribution of ultrasonic methods for quality assurance of sealing structures may be deduced.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 2015-09-15
KW - Ultrasonic reflection measurement
KW - Dry contact transducers in boreholes
KW - Interface salt-concrete / rock salt
KW - Ultrasonic imaging of internal reflectors
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346203
UR - http://www.ndt.net/?id=18304
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34620
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grothe, Sven
T1 - Ultrasonic signal evaluation used to detect temperature changes in a concrete specimen caused by a heating system
N2 - Ultrasonic measurement evaluation methods have been proven to be effective for detection of subtle changes, caused by temperature, load or moisture. To detect and localize temperature changes, a concrete block of 4 × 5 × 0.8 m3, including a heating cartridge and multiple temperature sensors, has been set up to change the temperature and monitor the temperature distribution in a certain area inside the specimen. An ultrasonic monitoring system with 40 ultrasonic sensors (20 transmitters, 20 receivers, 25 kHz central frequency) has been implemented on the specimen. Data from 400 sensor combinations was collected over the whole period of the experiment in an interval of 30 minutes. Quantitative methods (CodaWave Interferometry and Time of Flight method) were used to evaluate the changes in ultrasonic travel-time caused by the heating period, when the cartridge was active, and the cooling period after turning off the cartridge. Furthermore the travel-time changes from all 400 sensor combinations were used to locate the heating cartridge.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346387
UR - http://www.ndt.net/?id=18336
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 4
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bellon, Carsten
A1 - Jaenisch, Gerd-Rüdiger
A1 - Deresch, Andreas
T1 - Combining analytical and Monte Carlo modelling for industrial radiology
N2 - Modelling becomes more and more important in modern NDE. It is increasingly used to optimize techniques for complex applications, to support the preparation of written procedures, and for education purposes. To describe the complete chain of RT, the model includes simulating all necessary properties of X- or Gamma-ray sources, the interaction of photons with material with special attention to scattered radiation, the detection process, and the complete geometrical RT setup handling arbitrary parts or constructions. Depending on the given inspection problem and the influencing factors that should be addressed by the simulation, an appropriate physical model has to be chosen to describe the underlying interaction mechanisms. The simulator aRTist combines analytical and Monte Carlo methods to efficiently model the radiation transport such that transmission as well as scatter techniques can be modelled. In this contribution we Focus on Monte Carlo Simulation of scatter contribution within aRTist. Examples for RT/tomographic applications and back-scatter techniques are presented to demonstrate the usability of the presented simulation tool for a broad range of radiological applications.
T2 - 19th Wolrd Conference on Nondestructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - Radiography
KW - Computed tomography
KW - Simulation
KW - Monte Carlo methods
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-365856
SN - 978-3-940283-78-8
VL - 158
SP - 1
EP - 9
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung (DGZfP)
CY - Berlin, Germany
AN - OPUS4-36585
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neukammer, J.
A1 - Hussels, M.
A1 - Kummrow, A.
A1 - Devonshire, A.
A1 - Foy, C.
A1 - Huggett, J.
A1 - Parkes, H.
A1 - Zel, J.
A1 - Milavec, M.
A1 - Schimmel, H.
A1 - Unger, Wolfgang
A1 - Akgoz, M.
A1 - McHugh, V.
A1 - Grunert, H.-P.
A1 - Zeichhardt, H.
T1 - Survey results on nucleic acid tests of infectious diseases: present status and need for rapid and patient near diagnostics
N2 - This survey will discuss current and emerging isothermal and rapid polymerase chain reaction (PCR) based nucleic acid amplification methods for patient near diagnostics. To assess the clinical need of rapid diagnostics for infectious diseases based on nucleic acid tests (NATs) we performed and analysed a questionnaire among laboratories participating in corresponding INSTAND ring trials for external quality assurance. The questions concerning new amplification technologies like isothermal nucleic acid amplification, potentially suited to significantly decrease turnaround times, were complemented by questions to evaluate the present status of NATs. Besides end-users, companies were also addressed by sending out a manufacturer specific questionnaire. Analysis of the answers from 48 laboratories in 14 European countries revealed that a much shorter turnaround time is requested for selected pathogens compared to about 2 h or longer when applying temperature cycling amplification, i.e. PCR. In this context, most frequently mentioned were MRSA, norovirus, influenza A and B viruses, cytomegalovirus (CMV) as well as hepatitis B virus (HBV) and hepatitis C virus (HCV). At present, 8% of the laboratories having participated in this survey apply isothermal amplification of nucleic acid to identify infectious pathogens.
KW - Nucleic acid tests
KW - Infectious diseases
KW - Virus detection
KW - Bacteria detection
KW - Isothermal nucleic acid amplification
KW - Status report
KW - Questionnaire
KW - NAT
KW - PCR
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:0183-lab0000160
UR - http://www.egms.de/static/en/journals/lab/2015-6/lab000016.shtml
DO - https://doi.org/10.3205/lab000016
SN - 1869-4241
VL - 6
SP - 1
EP - 11
PB - GMS
CY - Düsseldorf
AN - OPUS4-36133
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matkovic, A.
A1 - Vasic, B.
A1 - Pesic, J.
A1 - Prinz, J.
A1 - Bald, Ilko
A1 - Milosavljevic, A. R.
A1 - Gajic, R.
T1 - Enhanced structural stability of DNA origami nanostructures by graphene encapsulation
N2 - Wedemonstrate that a single-layer graphene replicates the shape ofDNAorigami nanostructures very well. It can be employed as a protective layer for the enhancement of structural stability of DNA origami nanostructures. Using the AFM based manipulation, we show that the normal force required to damage graphene encapsulated DNA origami nanostructures is over an order of magnitude greater
than for the unprotected ones. In addition, we show that graphene encapsulation offers protection to the DNA origami nanostructures against prolonged exposure to deionized water, and multiple immersions. Through these results we demonstrate that graphene encapsulated DNA origami nanostructures are strong enough to sustain various solution phase processing, lithography and
transfer steps, thus extending the limits of DNA-mediated bottom-up fabrication.
KW - atomic force microscopy
KW - graphene
KW - DNA origami nanostructures
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358741
UR - http://iopscience.iop.org/article/10.1088/1367-2630/18/2/025016
DO - https://doi.org/10.1088/1367-2630/18/2/025016
SN - 1367-2630
VL - 18
SP - 025016
PB - IOP PUBLISHING LTD
CY - Bristol, UK
AN - OPUS4-35874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kopyra, J.
A1 - Keller, A.
A1 - Bald, Ilko
T1 - On the role of fluoro-substituted nucleosides in DNA radiosensitization for tumor radiation therapy
N2 - Gemcitabine (2',2'-difluorocytidine) is a well-known radiosensitizer routinely applied in concomitant chemoradiotherapy. During irradiation of biological media with high-energy radiation secondary low-energy (<10 eV) electrons are produced that can directly induce chemical bond breakage in DNA by dissociative electron attachment (DEA). Here, we investigate and compare DEA to the three molecules 2'-deoxycytidine, 2'-deoxy-5-fluorocytidine, and gemcitabine. Fluorination at specific molecular sites, i.e., nucleobase or sugar moiety, is found to control electron attachment and subsequent dissociation pathways. The presence of two fluorine atoms at the sugar ring results in more efficient electron attachment to the sugar moiety and subsequent bond cleavage. For the formation of the dehydrogenated nucleobase anion, we obtain an enhancement factor of 2.8 upon fluorination of the sugar, whereas the enhancement factor is 5.5 when the nucleobase is fluorinated. The observed fragmentation reactions suggest enhanced DNA strand breakage induced by secondary electrons when gemcitabine is incorporated into DNA.
KW - Dissociative electron attachment
KW - DNA radiation damage
KW - Gemcitabine
KW - DNA radiosensitizer
KW - Tumor radiation therapy
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-302872
DO - https://doi.org/10.1039/c3ra46735j
SN - 2046-2069
VL - 4
IS - 13
SP - 6825
EP - 6829
PB - RSC Publishing
CY - London
AN - OPUS4-30287
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zheng, H.
A1 - Kappatos, V.
A1 - Niederleithinger, Ernst
A1 - Ertel, Jens-Peter
A1 - Grohmann, Maria
A1 - Selcuk, C.
A1 - Gan, T.-H.
T1 - Defect detection in concrete pile using impulse response measurements with sine sweep excitations
N2 - For pile integrity inspection, a low cost and portable shaker was used to create the sine sweep signal for pile excitation. The impulse response function, calculated by the deconvolution of pile response from the sine sweep excitation, was proposed to identify the echoes in the piles due to the pile’s impedance changes. The proposed methodology has been evaluated and validated both numerically and experimentally. Based on the results from the simulations and experiments, it was found that the impulse response measurement with sine sweep excitation could be an effective tool to detect the echoes of the pile toe and the defects in the pile.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Impulse response function
KW - Sine sweep excitation
KW - Pile integrity
KW - Damage detection
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-347157
SN - 1435-4934
SP - 1
EP - 4
PB - Technische Universität Berlin / Bundesanstalt für Materialforschung und -prüfung
AN - OPUS4-34715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pretsch, Thorsten
T1 - Review on the functional determinants and durability of shape memory polymers
N2 - Shape memory polymers (SMP) belong to the class of stimuli-responsive materials and have generated significant research interest. Their capability to retain an imposed, temporary shape and to recover the initial, permanent shape upon exposure to an external stimulus depends on the "functional determinants", which in simplistic terms, can be divided into structural/morphological and processing/environmental factors. The primary aim of the first part of this review is to reflect the knowledge about these fundamental relationships. In a next step, recent advances in shape memory polymer composites are summarized. In contrast to earlier reviews, studies on the impairment of shape memory properties through various factors, such as aging, compression and hibernation, lubricants, UV light and thermo-mechanical cycling, are extensively reviewed. Apart from summarizing the state-of-the-art in SMP research, recent progress is commented.
KW - Shape memory polymer
KW - Active polymer
KW - Shape memory polymer composite
KW - Shape memory properties
KW - Functionality
KW - Degradation
KW - Aging
KW - Functional determinants
KW - Thermo-mechanical testing
KW - Durability
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-217390
UR - http://www.mdpi.com/2073-4360/2/3/120/pdf
DO - https://doi.org/10.3390/polym2030120
SN - 2073-4360
VL - 2
IS - 3
SP - 120
EP - 158
PB - MDPI
CY - Basel
AN - OPUS4-21739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hernández-Nava, E.
A1 - Tammas-Williams, S.
A1 - Smith, C.
A1 - Léonard, Fabien
A1 - Withers, P. J.
A1 - Todd, I.
A1 - Goodall, R.
T1 - X-ray tomography characterisation of lattice structures processed by selective electron beam melting
N2 - Metallic lattice structures intentionally contain open porosity; however, they can also contain unwanted closed porosity within the structural members. The entrained porosity and defects within three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM), is assessed from X-ray computed tomography (CT) scans. The results suggest that horizontal struts that are built upon loose powder show particularly high (~20 x 10⁻³ vol %) levels of pores, as do nodes at which many (in our case 24) struts meet. On the other hand, for struts more closely aligned (0° to 54°) to the build direction, the fraction of porosity appears to be much lower (~0.17 x 10⁻³%) arising mainly from pores contained within the original atomised powder particles.
KW - Cellular solids
KW - Aqdditive manufacturing
KW - Computed tomography
KW - Titanium alloys
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413689
UR - http://www.mdpi.com/2075-4701/7/8/300
DO - https://doi.org/10.3390/met7080300
SN - 2075-4701
VL - 7
IS - 8
SP - Article 300, 1
EP - 12
PB - MDPI
AN - OPUS4-41368
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naresh-Kumar, G.
A1 - Vilalta-Clemente, A.
A1 - Jussila, H.
A1 - Winkelmann, Aimo
A1 - Nolze, Gert
A1 - Vespucci, S.
A1 - Nagarajan, S.
A1 - Wilkinson, A. J.
A1 - Trager-Cowan, C.
T1 - Quantitative imaging of anti-phase domains by polarity sensitive orientation mapping using electron backscatter diffraction
N2 - Advanced structural characterisation techniques which are rapid to use, non-destructive and structurally definitive on the nanoscale are in demand, especially for a detailed understanding of extended-defects and their influence on the properties of materials. We have applied the electron
backscatter diffraction (EBSD) technique in a scanning electron microscope to non-destructively
characterise and quantify antiphase domains (APDs) in GaP thin films grown on different (001)Si substrates with different offcuts. We were able to image and quantify APDs by relating the asymmetrical intensity distributions observed in the EBSD patterns acquired experimentally and comparing the same with the dynamical electron diffraction simulations. Additionally mean angular error maps were also plotted using automated cross-correlation based approaches to image APDs.
Samples grown on substrates with a 4° offcut from the [110] do not show any APDs, whereas samples grown on the exactly oriented substrates contain APDs. The procedures described in our work can be
adopted for characterising a wide range of other material systems possessing non-centrosymmetric point groups.
KW - Polarity
KW - Semiconductor
KW - Antiphase boundary
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420167
SN - 2045-2322
VL - 7
SP - Article 10916, 1
EP - 10
AN - OPUS4-42016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lai Wai-Lok, Wallace
A1 - Kind, Thomas
A1 - Wiggenhauser, Herbert
T1 - A study of concrete hydration and dielectric relaxation mechanism using ground penetrating radar and short-time fourier transform
N2 - Ground penetrating radar (GPR) was used to characterize the frequency-dependent dielectric relaxation phenomena in ordinary Portland cement (OPC) hydration in concrete changing from fresh to hardened state. The study was experimented by measuring the changes of GPR A-scan waveforms over a period of 90 days, and processed the waveforms with short-time Fourier transform (STFT) in joint time-frequency analysis (JTFA) domain rather than a conventional time or frequency domain alone. The signals of the direct wave traveled at the concrete surface and the reflected wave from an embedded steel bar were transformed with STFT, in which the changes of peak frequency over ages were tracked. The peak frequencies were found to increase with ages and the patterns were found to match closely with primarily the well-known OPC hydration process and secondarily, the evaporation effect. The close match is contributed to the simultaneous effects converting free to bound water over time, on both conventional OPC hydration and dielectric relaxation mechanisms.
KW - Soil water content
KW - Wet soil
KW - Microwave
KW - Moisture
KW - GPR
KW - Dispersion
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-239723
DO - https://doi.org/10.1155/2010/317216
SN - 1687-6172
IS - Article ID 317216
SP - 1
EP - 14
PB - Hindawi Publ.
CY - New York, NY, USA
AN - OPUS4-23972
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shokouhi, Parisa
A1 - Zoëga, Andreas
A1 - Wiggenhauser, Herbert
T1 - Nondestructive investigation of stress-induced damage in concrete
N2 - The changes in the sonic surface wave velocity of concrete under stress were investigated in this paper. Surface wave velocities at
sonic frequency range were measured on a prismatic concrete specimen undergoing several cycles of uniaxial compression. The
loading was applied (or removed) gradually in predefined small steps (stress-controlled). The surface wave velocity was measured
at every load step during both loading and unloading phases. Acoustic Emission (AE) test was conducted simultaneously to
monitor the microcracking activities at different levels of loading. It was found that the sonic surface wave velocity is highly stress
dependent and the velocity-stress relationship follows a particular trend. The observed trend could be explained by a combination
of acoustoelasticity and microcracking theories, each valid over a certain range of applied stresses. Having measured the velocities
while unloading, when the material suffers no further damage, the effect of stress and damage could be differentiated. The slope
of the velocity-stress curves over the elastic region was calculated for different load cycles. This quantity was normalized to yield a
dimensionless nonlinear parameter. This parameter generally increases with the level of induced damage in concrete.
KW - Nondestructive testing (NDT)
KW - Surface wave velocity
KW - Concrete
KW - Acoustoelasticity
KW - Microcracking
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-215943
UR - http://downloads.hindawi.com/journals/ace/2010/740189.pdf
DO - https://doi.org/10.1155/2010/740189
SN - 1687-8094
SN - 1687-8086
VL - 2010
IS - Article ID 740189
SP - 1
EP - 9
PB - Hindawi Publ. Corp.
CY - New York, NY, USA
AN - OPUS4-21594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Moreira, E.V.
A1 - Rabello, J.M.B.
A1 - Pereira, M.d.S.
A1 - Lopes, R.T.
A1 - Zscherpel, Uwe
T1 - Digital radiography using digital detector arrays fulfills critical applications for offshore pipelines
N2 - Digital radiography in the inspection of welded pipes to be installed under deep water offshore gas and oil pipelines, like a presalt in Brazil, in the paper has been investigated. The aim is to use digital radiography for nondestructive testing of welds as it is already in use in the medical, aerospace, security, automotive, and petrochemical sectors. Among the current options, the DDA (Digital Detector Array) is considered as one of the best solutions to replace industrial films, as well as to increase the sensitivity to reduce the inspection cycle time. This paper shows the results of this new technique, comparing it to radiography with industrial films systems. In this paper, 20 test specimens of longitudinal welded pipe joints, specially prepared with artificial defects like cracks, lack of fusion, lack of penetration, and porosities and slag inclusions with varying dimensions and in 06 different base metal wall thicknesses, were tested and a comparison of the techniques was made. These experiments verified the purposed rules for parameter definitions and selections to control the required digital radiographic image quality as described in the draft international standard ISO/DIS 10893-7. This draft is first standard establishing the parameters for digital radiography on weld seam of welded steel pipes for pressure purposes to be used on gas and oil pipelines.
KW - Zerstörungsfreie Prüfung von Schweißnähten
KW - Durchstrahlungsprüfung
KW - Digitale Radiologie
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-225319
DO - https://doi.org/10.1155/2010/894643
SN - 1687-6172
VL - 2010
IS - Article ID 894643
SP - 1
EP - 7
PB - Hindawi Publ.
CY - New York, NY, USA
AN - OPUS4-22531
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guitton-Spassky, Tiffany
A1 - Schade, Boris
A1 - Zoister, Christian
A1 - Veronese, Eleonora
A1 - Rosati, Marta
A1 - Baldelli Bombelli, Francesca
A1 - Cavallo, Gabriella
A1 - Thünemann, Andreas
A1 - Ghermezcheshme, Hassan
A1 - Makki, Hesam
A1 - Netz, Roland R.
A1 - Ludwig, Kai
A1 - Metrangolo, Pierangelo
A1 - Singh, Abhishek Kumar
A1 - Haag, Rainer
T1 - Fluorinated Hexosome Carriers for Enhanced Solubility of Drugs
N2 - Designing nanomaterials for drug encapsulation is a crucial, yet challenging, aspect for pharmaceutical development. An important step is synthesizing amphiphiles that form stable supramolecular systems for efficient drug loading. In the case of fluorinated drugs, these have superior properties and also a tendency toward reduced water solubility. For the first time, we report here fluorinated hexosome carriers made from nonionic dendritic amphiphiles, capable of encapsulating the fluorinated drug Leflunomide with high efficiency (62 ± 3%) and increasing its solubility by 12-fold. We synthesized amphiphiles with varying tail groups (fluorinated/alkylated), and their supramolecular self-assembly was investigated using cryogenic transmission electron microscopy and small-angle X-ray scattering. Furthermore, Leflunomide and its equivalent nonfluorinated counterpart were encapsulated within fluorinated and nonfluorinated assemblies. Self-assembly and encapsulation mechanisms were well supported by coarse-grained molecular simulations, yielding a fundamental understanding of the new systems.
KW - PEFAS
KW - Small-angle X-ray scattering
KW - SAXS
KW - Reference method
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632002
DO - https://doi.org/10.1021/jacsau.5c00198
SN - 2691-3704
VL - 5
IS - 5
SP - 2223
EP - 2236
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-63200
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhang, Qiang
A1 - Heuchel, Matthias
A1 - Thünemann, Andreas
A1 - Machatscheck, Rainhard
T1 - The role of diffusion in the hydrolytic degradation of poly(lactic-co-glycolic acid): A molecular perspective
N2 - This research emphasizes the importance of internal surface erosion as a key factor in the hydrolytic degradation of PLGA (poly(D,L-lactic-co-glycolic acid)) providing an alternative view of the established surface and bulk erosion degradation modes. Using molecular dynamics (MD) simulations, this study reveals the role of water and oligomer diffusion during the degradation of PLGA and highlights the importance of water channels formed as the overall water content increases. We found that these continuous water channels play a crucial role in accelerating the transport of water and the release of degradation products from the polymer matrix, as the diffusion coefficients of water and small oligomers exhibit significant differences spanning 2 to 3 orders of magnitude between the water and polymer phases. Water follows a different diffusion mechanism than polymer fragments. The diffusion rate of the fragments up to a size of octamers was found to be size-dependent and reasonably well approximated by a 1/N behavior, in line with the Rouse model.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - PLGA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621250
DO - https://doi.org/10.1016/j.polymdegradstab.2024.111119
VL - 232
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-62125
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Alyna
A1 - Holtzheimer, Lea
A1 - Clarke, Coby
A1 - Thünemann, Andreas
A1 - Taubert, Andreas
T1 - Complex Self-Organization in n-Alkylammonium Sulfobetaine Zwitterions with High Thermal Stabilities and High Expansion Coefficients
N2 - Sulfobetaine zwitterions made from n-alkyl dimethylamines and butanesultone yield a series of n-alkylammonium sulfobetaine zwitterions with complex self-organization behavior. The compounds are thermally quite stable and the length of the alkyl chain directly affects all phase transition temperatures of the compounds: the longer the alkyl chain, the higher the transition temperature. All compounds exhibit lamellar order and the different phases are characterized by a lower temperature orthorhombic and a higher temperature hexagonal in-plane order. The phase transition from the orthorhombic to the hexagonal phase is always associated with an increase of the long period. The phase transition is also associated with a rather high thermal expansion coefficient.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanostructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626276
DO - https://doi.org/10.1021/acs.langmuir.4c02892
SN - 1520-5827
VL - 41
SP - 4422
EP - 4434
PB - American Chemical Society (ACS)
AN - OPUS4-62627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kieserling, Helena
A1 - Sieg, Holger
A1 - Heilscher, Jasmin
A1 - Drusch, Stephan
A1 - Braeuning, Albert
A1 - Thünemann, Andreas
A1 - Rohn, Sascha
T1 - Towards Understanding Particle-Protein Complexes: Physicochemical, Structural, and Cellbiological Characterization of β-Lactoglobulin Interactions with Silica, Polylactic Acid, and Polyethylene Terephthalate Nanoparticles
N2 - Nanoplastic particles and their additives are increasingly present in the food chain, interacting with biomacromolecules with not yet known consequences. A protein corona forms around the particles in these usually complex matrices, primarily with a first contact at surface-active proteins. However, systematic studies on the interactions between the particles and proteins –especially regarding protein affinity and structural changes due to surface properties like polarity – are limited. It is also unclear whether the protein corona can "mask" the particles, mimic protein properties, and induce cytotoxic effects when internalized by mammalian cells. This study aimed at investigating the physicochemical properties of model particle-protein complexes, the structural changes of adsorbed proteins, and their effects on Caco-2 cells. Whey protein β-lactoglobulin (β-Lg) was used as a well-characterized model protein and studied in a mixture with nanoparticles of varying polarity, specifically silica, polylactic acid (PLA), and polyethylene terephthalate (PET). The physicochemical analyses included measurements of the hydrodynamic diameter and the zeta potential, while the protein conformational changes were analyzed using Fourier-transform-infrared spectroscopy (FTIR) and intrinsic fluorescence. Cellular uptake in Caco-2 cells was assessed through flow cytometry, cell viability was measured using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium-bromide (MTT) assay, and cellular impedance was analyzed with xCELLigence® technology. The results indicated that β-Lg had the highest affinity for hydrophilic silica particles, forming silica-β-Lg complexes and large aggregates through electrostatic interactions. The affinity decreased for PLA and was lowest for hydrophobic PET, which formed smaller complexes. Adsorption onto silica caused partial unfolding and refolding of β-Lg. The silica-β-Lg complexes were internalized by Caco-2 cells, impairing cell proliferation. In contrast, PLA- and PET-protein complexes were not internalized, though PLA complexes slightly reduced cell viability. This study enhances our understanding of protein adsorption on nanoparticles and its potential biological effects.
KW - Nanoplastics
KW - Microplastics
KW - Reference materials
KW - Scattering
KW - DLS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630093
DO - https://doi.org/10.1016/j.colsurfb.2025.114702
SN - 1873-4367
VL - 253
SP - 1
EP - 12
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mikhlin, Yuri
A1 - Muzikansky, Anya
A1 - Zysler, Melina
A1 - Thünemann, Andreas
A1 - Zitoun, David
T1 - Emerging electrochemistry of high-concentration colloids: Redox-activity, wide potential window and electrophoretic transport of iron oxide nanoparticles
N2 - High-concentration, steric stabilizer free colloids and particularly their electrochemical behavior remains almost unexplored. Herein, we report on the electrochemistry (cyclic voltammetry, impedance spectroscopy, etc.) of highly concentrated aqueous colloidal dispersion up to 800 g/L of citrate-capped ∼11 nm Fe3-xO4 nanoparticles (NPs) without background electrolyte on glassy carbon electrodes. X-ray photoelectron spectroscopy was applied to analyze the reaction products. Solid-state Fe(II)/Fe(III) conversion was concluded to determine the cathodic and anodic faradaic reactions of the particles, with the currents depending on approximately square root of the concentration. The electrochemical reactions are coupled with the electrophoretic transfer of the negatively charged NPs on toward the anode, with the ohmic-type behavior in the bulk demonstrated by the nearly linear voltametric cathodic curves and frequency-independent impedance above ∼10–100 Hz. Accumulation and clogging of the NPs retards diffusion near anode. Hydrogen and especially oxygen evolution are arrested, and very large oxidation overpotentials result in extraordinary wide, up to 12 V, electrochemical window of water stability. The findings shed light onto basic features of the electrochemistry of high-concentration colloids without added electrolyte and their potential applications in redox flow batteries, electrophoretic deposition and beyond.
KW - Nanoplastics
KW - SAXS
KW - Small-angle X-ray scattering
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644340
DO - https://doi.org/10.1016/j.jcis.2025.139247
SN - 0021-9797
VL - 703
SP - 1
EP - 18
PB - Elsevier Inc.
AN - OPUS4-64434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kapoor, M.
A1 - Overgaard Christensen, Ch.
A1 - Wittrup Schmidt, J.
A1 - Dalsgaard Sørensen, J.
A1 - Thöns, Sebastian
T1 - Decision analytic approach for the reclassification of concrete bridges by using elastic limit information from proof loading
N2 - Reclassification of bridges, i.e., a change in load rating, using reliability-based methods and a direct update with proof load information has been presented by many authors. However, bridge reclassification has hardly been studied from a decision analytic perspective, i.e., with quantification of the risks and benefits of different classification choices, and the expected benefit gain from proof loading. We derive, explain and exemplify a decision analytic approach for bridge reclassification along with models for (1) elastic and ultimate capacity and their adaptation with proof load information, (2) proof load information with classification outcomes accounting for target reliabilities and, (3) utilities including socio-economic benefits from reclassification. The approach and models are exemplified with a case study based on reclassification of bridges with a low existing classification. Decision rules, for practical use by a highway authority to find the optimal classification, are identified and documented based on: (1) the measurement of the capacity at elastic limit by proof loading, (2) the bridge reclassification benefits, and, (3) the required annual reliability level. From a Value of Information analysis, it is concluded that the proof load information is highly valuable for reclassification in cases of high socio-economic benefits and high reliability requirements.
KW - Proof loading
KW - Structural reliability
KW - Value of information
KW - Decision analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596845
DO - https://doi.org/10.1016/j.ress.2022.109049
SN - 0951-8320/
VL - 232
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-59684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Schaupp, Thomas
A1 - Kannengießer, Thomas
A1 - Burger, S.
A1 - Zinke, M.
A1 - Jüttner, S.
T1 - Ermittlung geeigneter Wärmeführungen zur Vermeidung wasserstoffunterstützter Kaltrisse beim Schweißen höherfester Feinkornbaustähle mit modifiziertem Sprühlichtbogen
N2 - Um den wachsenden Anforderungen an den stofflichen und konstruktiven Leichtbau sowie den Forderungen nach Ressourceneffizienz Rechnung zu tragen, werden in vielen Industriebranchen zunehmend höherfeste Feinkornbaustähle mit Streckgrenzen ≥ 690 MPa eingesetzt. Allerdings werden mit zunehmender Festigkeit deutlich höhere Anforderungen an deren schweißtechnische Verarbeitung gestellt. Weil gerade die Sensibilität gegenüber einer Degradation der mechanischen Eigenschaften der höherfesten Feinkornbaustähle durch den beim Schweißen aufgenommenen Wasserstoff mit steigender Festigkeit zunimmt, ist auf eine geeignete Wärmeführung zu achten. Für konventionelle MAG-Schweißprozesse liegen bereits Erfahrungen und Regelwerke zur Wärmeführung und entsprechende Wasserstoffgrenzwerte vor. Moderne Invertertechnik ermöglichte die Entwicklung modifizierter Sprühlichtbögen (mod. SLB). Im Vergleich zu konventionellen Lichtbogenprozessen wird ein äußerst kurzer und richtungsstabiler Lichtbogen, eine höhere Abschmelzleistung, ein größerer Kontaktrohrabstand und ein tieferer Einbrand realisiert. Neben den bekannten Vorteilen lassen außerdem reduzierte mögliche Nahtöffnungswinkel einen anderen Lagenaufbau und unterschiedliche Geometrien der einzelnen Schweißraupen erwarten. Jedoch fehlen hierzu Aussagen über den schweißverfahrensspezifisch eingetragenen Wasserstoff und die damit einhergehende Kaltrissgefahr. Hierzu lagen in der Industrie, besonders bei den KMU, kaum Kenntnisse vor und sollten deshalb als Ziel dieses Forschungsprojektes erarbeitet werden.
Die vergleichenden Untersuchungen mit konventionellem Übergangslichtbogen und mod. SLB mit angepasster Nahtkonfiguration erfolgten an freischrumpfenden Stumpfstoßverbindungen sowohl mit Massivdraht als auch Metallpulverfülldraht. Zur Durchführung der Untersuchungen wurde eine Methodik entwickelt, die es ermöglicht, im Schweißgut realer Verbindungsschweißungen die Wasserstoffkonzentration reproduzierbar zu bestimmen. Anhand der Analysen konnte gezeigt werden, dass die Schweißprozessparameter die in das Schweißgut eingebrachte Wasserstoffkonzentration in Einlagenschweißungen beeinflussen. Auch beim Mehrlagenschweißen gestaltet sich der Wasserstoffeintrag abhängig von den Schweißprozessparametern und ist auf den unterschiedlichen Lagenaufbau zurückzuführen. Grundsätzlich ist den erarbeiteten Ergebnissen zu entnehmen, dass im Schweißgut von Stumpfstoßverbindungen mit abgesenktem Nahtöffnungswinkel erhöhte mittlere Wasserstoffkonzentrationen existieren. Außerdem beinhalten Schweißgüter aus Metallpulverfülldraht höhere Wasserstoffmengen als Massivdrahtschweißungen. Geeignete Wärmeführungen führten zu einer signifikanten Reduzierung der Wasserstoffkonzentration bei dem Einsatz der Nahtkonfiguration mit abgesenktem Nahtöffnungswinkel. Dabei erwies sich eine Nachwärmprozedur aus der Schweißwärme heraus als zielführend. Die Vorstellung von Zwischenergebnissen in Normungsgremien erfolgten, um mittelfristig vor allem den KMU eine sichere Verarbeitung höherfester Feinkornbaustähle zu ermöglichen.
Die dargestellten Ergebnisse stellen einen wichtigen Beitrag zur sicheren Auslegung von Schweißkonstruktionen aus höherfestem Feinkornbaustahl dar und ermöglichen den KMU die technischen und wirtschaftlichen Vorteile der mod. SLB-Prozesse auszunutzen sowie unter Berücksichtigung der wasserstoffunterstützten Kaltrissbildung kostenintensive Nacharbeiten zu reduzieren.
KW - Wasserstoff
KW - MAG-Schweißen
KW - Höherfester Feinkornbaustahl
KW - Schweißprozessparameter
KW - Wärmeführung
KW - Kaltrissprüfung
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425946
SP - 1
EP - 94
AN - OPUS4-42594
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bald, Ilko
A1 - Keller, A.
T1 - Molecular processes studied at a single-molecule level using DNA origami nanostructures and atomic force microscopy
N2 - DNA origami nanostructures allow for the arrangement of different functionalities such as proteins, specific DNA structures, nanoparticles, and various chemical modifications with unprecedented precision. The arranged functional entities can be visualized by atomic force microscopy (AFM) which enables the study of molecular processes at a single-molecular level. Examples comprise the investigation of chemical reactions, electron-induced bond breaking, enzymatic binding and cleavage events, and conformational transitions in DNA. In this paper, we provide an overview of the advances achieved in the field of single-molecule investigations by applying atomic force microscopy to functionalized DNA origami substrates.
KW - DNA origami
KW - atomic force microscopy
KW - single-molecule analysis
KW - DNA radiation damage
KW - protein binding
KW - enzyme reactions
KW - G quadruplexes
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314343
DO - https://doi.org/10.3390/molecules190913803
SN - 1420-3049
VL - 19
IS - 9
SP - 13803
EP - 13823
PB - MDPI
CY - Basel
AN - OPUS4-31434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bender, P.
A1 - Bogart, L.K.
A1 - Posth, O.
A1 - Szczerba, Wojciech
A1 - Rogers, S.E.
A1 - Castro, A.
A1 - Nilsson, L.
A1 - Zeng, L. J.
A1 - Sugunan, A.
A1 - Sommertune, J.
A1 - Fornara, A.
A1 - Gonzales-Alonso, D.
A1 - Fernandez Barquin, L.
A1 - Johansson, C.
T1 - Structural and magnetic properties of multi-core nanoparticles analysed using a generalised numerical inversion method
N2 - The structural and magnetic properties of magnetic multi-core particles were determined by numerical inversion of small angle scattering and isothermal magnetisation data. The investigated particles consist of iron oxide nanoparticle cores (9 nm) embedded in poly(styrene) spheres (160 nm). A thorough physical characterisation of the particles included transmission electron microscopy, X-ray diffraction and asymmetrical flow field-flow fractionation. Their structure was ultimately disclosed by an indirect Fourier transform of static light scattering, small angle X-ray scattering and small angle neutron scattering data of the colloidal dispersion. The extracted pair distance distribution functions clearly indicated that the cores were mostly accumulated in the outer surface layers of the poly(styrene) spheres. To investigate the magnetic properties, the isothermal magnetisation curves of the multi-core particles (immobilised and dispersed in water) were analysed. The study stands out by applying the same numerical approach to extract the apparent moment distributions of the particles as for the indirect Fourier transform. It could be shown that the main peak of the apparent moment distributions correlated to the expected intrinsic moment distribution of the cores. Additional peaks were observed which signaled deviations of the isothermal magnetisation behavior from the non-interacting case, indicating weak dipolar interactions.
KW - Numerical inversion
KW - Magnetic nanoparticles
KW - Iron oxides
KW - Magnetic properties
KW - Structural properties
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-400952
DO - https://doi.org/10.1038/srep45990
SN - 2045-2322
VL - 7
SP - Article 45990, 1
EP - 14
AN - OPUS4-40095
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Agirrezabal-Telleria, Iker
A1 - Guo, Y.
A1 - Hemmann, Felix
A1 - Arias, P. L.
A1 - Kemnitz, E.
T1 - Dehydration of xylose and glucose to furan derivatives using bifunctional partially hydroxylated MgF2 catalysts and N2-stripping
N2 - The current furfural production yield is low due to the use of non-selective homogeneous catalysts and expensive separation. In this work, partially hydroxylated MgF2 catalysts, synthesized using different water contents, were screened during xylose dehydration in watertoluene at 160 °C. The different Lewis/Brønsted ratios on the MgF2 catalysts showed that under-coordinated Mg can isomerize xylose to xylulose, whilst the surface OH-groups were responsible for the dehydration reactions. The presence of glucose as a co-carbohydrate reduced the furfural selectivity from 86 to 81%, whilst it also led to high 5-hydroxymethylfurfural selectivity. The tests catalyzed by MgF2 in combination with simultaneous N2-stripping showed that a furfural selectivity of 87% could be achieved using low xylose loadings. Moreover, the catalysts regenerated by H2O2 showed high activity during the dehydration tests in watertoluene at 160 °C.
KW - Bifunctional MgF2
KW - Lewis/Bronsted
KW - Carbohydrates
KW - Furan derivatives
KW - N2-stripping
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-305441
DO - https://doi.org/10.1039/c4cy00129j
SN - 2044-4753
SN - 2044-4761
VL - 4
IS - 5
SP - 1357
EP - 1368
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-30544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stoch, P.
A1 - Szczerba, Wojciech
A1 - Bodnar, W.
A1 - Ciecinska, M.
A1 - Stoch, A.
A1 - Burkel, E.
T1 - Structural properties of iron-phosphate glasses: spectroscopic studies and ab initio simulations
N2 - Vitrification is the most effective method for the immobilization of hazardous waste by incorporating toxic elements into a glass structure. Iron phosphate glasses are presently being considered as matrices for the storage of radioactive waste, even of those which cannot be vitrified using conventional borosilicate waste glass. In this study, a structural model of 60P2O5–40Fe2O3 glass is proposed. The model is based on the crystal structure of FePO4 which is composed of [FeO4][PO4] tetrahedral rings. The rings are optimized using the DFT method and the obtained theoretical FTIR and Raman spectra are being compared with their experimental counterparts. Moreover, the proposed model is in very good agreement with X-ray absorption fine structure spectroscopy (XANES/EXAFS) and Mössbauer spectroscopy measurements. According to the calculations the Fe3+ is in tetrahedral and five-fold coordination. The maximal predicted load of waste constituents into the glass without rebuilding of the structure is 30 mol%. Below this content, waste constituents balance the charge of [FeO4]- tetrahedra which leads to their strong bonding to the glass resulting in an increase of the chemical durability, transformation and melting temperatures and density.
KW - Glass
KW - Iron
KW - DFT simulations
KW - Mössbauer spectroscopy
KW - XANES/EXAFS
KW - FTIR spectroscopy
KW - Raman spectroscopy
KW - Coordination
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317351
DO - https://doi.org/10.1039/c4cp03113j
SN - 1463-9076
SN - 1463-9084
VL - 16
IS - 37
SP - 19917
EP - 19927
PB - The Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-31735
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wollschläger, Nicole
A1 - Tasdemir, Z.
A1 - Häusler, Ines
A1 - Leblebici, Y.
A1 - Österle, Werner
A1 - Alaca, B. E.
T1 - Determination of the elastic behavior of silicon nanowires within a scanning electron microscope
N2 - Three-point bending tests were performed on double-anchored, <110> silicon nanowire samples inside a scanning electron microscope (SEM) via a micromanipulator equipped with a piezo-resistive force sensor. Representing the upper and lower boundaries achievable in a consistent manner, silicon nanowires with widths of 35 nm and 74 nm and a height of 168 nm were fabricated. The nanowires were obtained monolithically along with their 10-m-tall supports through a top-down fabrication approach involving a series of etching processes. Hence, no interface compliance was introduced between supports and nanowires. Exact nanowire dimensions and cross-sectional features were determined by transmission electron microscopy (TEM) following sample preparation through focused ion beam (FIB) machining. Conducting the experiments inside an SEM chamber further raised the opportunity of the direct observation of any deviation from ideal loading conditions such as twisting, which was taken into consideration in simulations. Measured force-displacement behavior was observed to exhibit close resemblance to simulation results obtained by finite element modeling, when the bulk value of 169 GPa was taken as the modulus of elasticity for <110> silicon. Hence, test results show neither any size effect nor evidence of residual stresses for the considered nanoscale objects. The increased effect of the native oxide with reduced nanowire dimensions was captured as well. Thus this very simple in-situ testing method was found to be an alternative to elaborate AFM measurements on geometrically formidable nanostructures. The results demonstrate the applicability of the developed fabrication approach to the incorporation of silicon nanowires in functional micromechanical devices.
KW - Silicon nanowire
KW - Elastic behavior
KW - Scanning electron microscope
KW - Mechanical properties
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370383
DO - https://doi.org/10.1155/2016/4905838
VL - 2016
SP - Article 4905838, 1
EP - 6
PB - Hindawi Publishing Corporation
AN - OPUS4-37038
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Olejko, Lydia
A1 - Bald, Ilko
T1 - FRET efficiency and antenna effect in multi-color DNA origami-based light harvesting systems
N2 - Artificial light harvesting complexes find applications in artificial photosynthesis, photovoltaics and light harvesting chemical sensors. They are used to enhance the absorption of light of a reaction center which is often represented by a single acceptor. Here, we present different light harvesting systems on DNA origami structures and analyze systematically the light harvesting efficiency. By changing the number and arrangement of different fluorophores (FAM as donor, Cy3 as transmitter and Cy5 as acceptor molecules) the light harvesting efficiency is optimized to create a broadband absorption and to improve the antenna effect 1 (including two energy transfer steps) from 0.02 to 1.58, and the antenna effect 2 (including a single energy transfer step) from 0.04 to 8.7, i.e. the fluorescence emission of the acceptor is significantly higher when the light-harvesting antenna is excited at lower wavelength compared to direct excitation of the acceptor. The channeling of photo energy to the acceptor proceeds by Förster Resonance Energy Transfer (FRET) and we carefully analyze also the FRET efficiency of the different light harvesting systems. Accordingly, the antenna effect can be tuned by modifying the stoichiometry of donor, transmitter and acceptor dyes, whereas the FRET efficiency is mainly governed by the spectroscopic properties of dyes and their distances.
KW - DNA origami
KW - Light-harvesting
KW - FRET
KW - Antenna effect
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-405867
UR - http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra02114c#!divAbstract
DO - https://doi.org/10.1039/C7RA02114C
VL - 7
IS - 39
SP - 23924
EP - 23934
PB - The Royal Soc. of Chemistry
AN - OPUS4-40586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Österle, Werner
A1 - Nikonov, A. Y.
A1 - Dmitriev, A. I.
ED - Krzanowski, J.
T1 - MD sliding simulations of amorphous tribofilms consisting of either SiO2 or carbon
N2 - The sliding behaviors of two simplified tribofilms with amorphous structure consisting either of SiO₂ molecules or C atoms were simulated by molecular dynamics modeling. The objective was to identify mechanisms explaining the experimentally observed lubricating properties of the two amorphous films. The impacts of layer thickness, normal pressure, temperature and different substrate materials were studied systematically, while the sliding velocity was kept constant at 30 m/s. While the layer thickness was not critical, all the other parameters showed special effects under certain conditions. Normal pressure impeded void formation and could even eliminate voids if applied at high temperature. Stick-slip sliding was changed to smooth sliding at high temperature due to void healing. Considering the carbon film, high friction forces and shearing of the entire film was observed with diamond substrates, whereas interface sliding at low friction forces and an amorphous layer of iron mixed with carbon was observed if the supporting substrates consisted of α-Fe. Both films show a decrease of friction forces and smooth sliding behavior at elevated temperature, corresponding well to the tribological behavior of and advanced nanocomposite sliding against a steel disc under severe stressing conditions when high flash temperatures can be expected.
KW - dry friction
KW - amorphous silica film
KW - amorphous carbon film
KW - sliding simulation
KW - molecular dynamics
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-379367
DO - https://doi.org/10.3390/lubricants4030024
VL - 4
IS - 24
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-37936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Carl, Peter
A1 - Schneider, Rudolf
T1 - Optimization and evaluation of a hapten microarray using chemometric methods
N2 - The demands for the assessment of water quality are increasing steadily, making it necessary to routinely monitor multiple contaminants in water samples. For this application a hapten microarray was developed. In order to reach the required low detection limits a design of experiments (DoE) approach was used to optimize the assay performance. Here we show that a Box-Behnken design plan is an adequate choice for the straightforward exploration of hapten microarray assay parameters. For both read-out systems studied (fluorophore-labelled detection antibodies or enzymatic signal development followed by reflectometric scan, respectively), it was possible to significantly extend the measurement ranges. Furthermore, it could be shown that multivariate data analysis, here partial least squares regression (PLS), can improve the prediction accuracy of 'unknown' samples when used as calibration model, compared to classical, univariate data evaluation methods.
KW - Koffein
KW - Caffeine
KW - Proteine microarray
KW - Design of experiments
KW - Multivariate data analysis
KW - Partial least squares regression
KW - Small molecule detection
KW - Microarray
KW - Immunoarray
KW - Immunoassay
KW - ELISA
KW - Chemometrie
KW - Chemometrics
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-344672
DO - https://doi.org/10.1016/j.proeng.2015.08.684
SN - 1877-7058
VL - 120
SP - 501
EP - 506
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-34467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Siebler, Daniel
A1 - Rohwetter, Philipp
A1 - Brusenbach, R.
A1 - Plath, R.
T1 - Optical-only detection of partial discharge with fluorescent polymer optical fiber sensors
N2 - This paper reflects recent progress in the field of fluorescent polymer optical fiber sensors (F-POF) for partial discharge (PD) detection in high voltage (HV) cable accessories using optical-only PD detection by coincidence single photon counting. In experiments with artificial PD sources these sensors show the ability to detect optical emissions from picocoulomb-level PDs in a real-scale model of a translucent high voltage cable accessory. False positives (caused by detector noise) are efficiently suppressedwhile maintaining sufficient sensitivity,even when the sensor is located in an unfavorable position.
T2 - EUROSENSORS 2015
CY - Freiburg, Germany
DA - 06.09.2015
KW - Partial discharge
KW - Silicone rubber
KW - High voltage cable accessories
KW - Polymer optical fiber POF
KW - Fluorescence
KW - Coincidence
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337881
DO - https://doi.org/10.1016/j.proeng.2015.08.711
SN - 1877-7058
VL - 120
SP - 845
EP - 848
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-33788
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Mähner, D.
A1 - Sodeikat, Ch.
A1 - Maack, Stefan
T1 - ZfPBau-Verfahren an Elementwänden – Fallbeispiele und vergleichende Untersuchungen
N2 - Die zerstörungsfreien Prüfverfahren konnten ihre Fähigkeit bei der Untersuchung von Elementwänden in einzelnen Fallstudien erbringen. Aufbauend auf den Kenntnissen aus der Praxis und auf Testreihen im Rahmen von Laboruntersuchungen wurde ein erster Ringversuch geplant und durchgeführt. Im Rahmen dieses Ringversuchs wurden verschiedene Strukturdefekte und Einbauteile in Elementwände eingebaut. Die Messung der Wände erfolgte anschließend durch mehrere Messteams mit unterschiedlichen zerstörungsfreien Prüfverfahren. Zum Einsatz kamen hierbei das Ultraschall-Echo- und das Impact-Echo-Verfahren sowie das Impuls-Radar-Verfahren. Zur Verbesserung der Vergleichbarkeit zwischen den unterschiedlichen Prüfverfahren wurde auf die Elementwände ein einheitliches Messraster aufgebracht. Für eine möglichst objektive Messung der Wände erhielten die Messteams vor den Messungen keine Details zu den Strukturdefekten oder Einbauteilen. Die Prüfaufgabe bestand darin, die Wände mit dem jeweiligen Prüfverfahren zu untersuchen. Anschließend wurden die Ergebnisse der Messteams zentral gesammelt und ausgewertet. Anhand der zentralen Auswertung sollten Aussagen zu den eingebauten Inhomogenitäten ableitet werden. Hierdurch kann zum einen die Leistungsfähigkeit der Prüfverfahren an unterschiedlichsten Inhomogenitäten getestet werden, zum anderen können die Ergebnisse und somit die Prüfverfahren untereinander verglichen werden. Zu diesen in der Praxis immer häufiger vorkommenden Fragestellungen können grundsätzliche Aussagen zum Einsatz von zerstörungsfreien Prüfungen bei Elementwänden gewonnen werden. Über die Ergebnisse dieses Ringversuches wird nachfolgend berichtet.
T2 - Fachtagung Bauwerksdiagnose - Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben
CY - Berlin, Germany
DA - 25.02.2016
KW - Beton
KW - Zerstörungsfreie Prüfung im Bauwesen
KW - Elementwände
KW - WU-Bauwerke
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388331
UR - http://www.bauwerksdiagnose2016.de/Portals/bwd2016/BB/vortrag%2010.pdf
SP - 1
EP - 22
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V.
CY - Berlin
AN - OPUS4-38833
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stengel, Dominik
A1 - Mehdianpour, Milad
T1 - Finite element modelling of electrical overhead line cables under turbulent wind load
N2 - This paper presents a finite element model of an overhead transmission line using so called cable elements which allow reproducing the cable's nonlinear characteristics accurately employing only a few elements. Aerodynamic damping is considered in the equation of motion by taking into account the relative velocity between the flow of the wind and the moving structure. The wind flow itself is simulated by wave superposition making necessary assumptions on the lateral correlation between the wind velocities along the cable length. As result from the simulation, the following conclusions can be drawn. The first natural frequency of generally used wide spanning cables lies well below 1 Hz where also most of the energy content of the wind excitation is to be expected. Aerodynamic damping is significant for the moving cables holding very low structural damping which leads to a suppression of resonant amplification. This is particularly of interest regarding the support reaction which is dominated by the mean value and the so called background response. The latter is mostly influenced by the randomness of the wind flow, especially lateral to the main wind direction.
KW - Nonlinear Finite Element Formulations
KW - Nonlinear Equation of Motion
KW - Turbulent Wind Excitation
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304567
DO - https://doi.org/10.1155/2014/421587
SN - 2314-6494
SN - 2356-766X
VL - 2014
IS - Article ID 421587
SP - 1
EP - 8
PB - Hindawi Publ.
CY - New York, NY ; Cairo
AN - OPUS4-30456
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Maack, Stefan
A1 - Holst, R.
T1 - Rekonstruktion des Bestandsplans im Zuge der Nachrechnung der Brücke über die Leine bei Schwarmstedt
N2 - Der aktuell im Rahmen der Nachrechnungsrichtlinie geforderte Nachweis von Tragfähigkeit, Gebrauchstauglichkeit und Ermüdung der Brückenbauwerke im Bestand der Länder und des Bundes stellt eine enorme Herausforderung dar. Insbesondere bei unvollständigen oder fehlenden Bestandsplänen der Bauwerke sind Maßnahmen erforderlich, um die erforderlichen Informationen zu beschaffen. Ein wirkungsvolles Instrument können hierfür die zerstörungsfreien Prüfverfahren des Bauwesens sein. In dem präsentierten Forschungsprojekt erfolgte die Rekonstruktion eines Bestandsplanes direkt auf die Anforderungen des mit der Nachrechnung beauftragten Ingenieurbüros. Darüber hinaus wurde der Entwurf eines Leitfadens erstellt, der im Falle von unvollständigen oder fehlenden Bestandsplänen die Grundlagen für die Beauftragung und Durchführung der Nachrechnung schafft.
T2 - Fachtagung Bauwerksdiagnose 2016 - Praktische Anwendungen Zerstörungsfreier Prüfungen und Zukunftsaufgaben
CY - Berlin, Germany
DA - 25.02.2016
KW - Zerstörungsfreie Prüfung
KW - Nachrechnungsrichtlinie
KW - Brücken
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388355
UR - http://www.bauwerksdiagnose2016.de/Portals/bwd2016/BB/vortrag%206.pdf
SP - 1
EP - 14
PB - Deutsche Gesellschaft für zerstörungsfreie Prüfung e.V.
CY - Berlin
AN - OPUS4-38835
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pirskawetz, Stephan
A1 - Hüsken, Götz
A1 - Gründer, Klaus-Peter
A1 - Kadoke, Daniel
ED - Bohse, Jürgen
ED - Purschke, Matthias
T1 - Analyse der Schadensmechanismen biegebeanspruchter Stahlbetonbalken mittels zerstörungsfreier Prüftechniken
N2 - Der durch Kräfte senkrecht zur Stabachse belastete Balken ist eines der Haupttragelemente des Stahlbetonbaus. Biegebalken finden unter anderem Anwendung in Form von Brückenträgern oder Unterzügen. Die bei maximaler Beanspruchung auftretenden Versagensformen unterteilen sich dabei in Biege- und Querkraftversagen (Schubversagen). Ein Versagen des Balkens kann je nach Versagensmechanismus mit oder ohne Vorankündigung erfolgen. Gebräuchliche Bemessungskonzepte der Baupraxis zur Dimensionierung entsprechender Tragelemente zielen auf ein Versagen mit ausreichender Vorankündigung (große Verformungen oder breite Risse) ab, wie es z.B. beim sekundären Biegedruckversagen entsteht. Für die Zustandsüberwachung von Bauwerken (z.B. Brücken) mittels zerstörungsfreier Prüftechniken sind fundierte Kenntnisse zu den bei Biegebeanspruchung auftretenden Schadensmechanismen erforderlich. Im Rahmen eines BAM-internen Projektes sollen durch praxisnahe Untersuchungen an einer brückenähnlichen Referenzstruktur unterschiedliche auf das Tragwerk einwirkende thermische und mechanische Belastungen untersucht werden und in die Entwicklung eines Monitoringsystems einfließen. Anhand der aus Biegeversuchen vorliegenden Ergebnisse wird der Einsatz unterschiedlicher Methoden der zerstörungsfreien Materialprüfung gezeigt und deren Anwendbarkeit für die Analyse des Verformungsverhaltens von Stahlbetonbalken diskutiert. Hierzu wurde das Verformungsverhalten eines Stahlbetonbalkens (L = 2,75 m) in einem Vierpunkt-Biegeversuch im Labormaßstab untersucht. Das Hauptaugenmerk liegt dabei auf der Charakterisierung der ausschlaggebenden Versagensmodi durch die einzelnen zerstörungsfreien Prüfverfahren und der Vergleich zu klassischen Messmethoden (z.B. Verformungsmessung mittels induktiver Wegaufnehmer (IWA)). Die Biegeversuche wurden dazu durch Schallemissionsanalyse (SEA) und optische Verformungsanalyse mittels Stereo-Fotogrammetrie (SF) und Bildkorrelationsverfahren (BKV) begleitet.
T2 - 21. Kolloquium Schallemission
CY - Fulda, Germany
DA - 09.03.2017
KW - Optische Verformungsanalyse
KW - Rissbildung
KW - Schallemission
KW - Stahlbeton
KW - Tragverhalten bei Biegebeanspruchung
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393617
SN - 978-3-940283-82-5
VL - 59
SP - 1
EP - 10
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-39361
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maack, Stefan
A1 - Kneib, G.
T1 - Elastic wave propagation of ultrasound in bituminous road surfaces - simulations and measurements
N2 - Maintenance costs of road infrastructure are increasing steadily. The main cause of this is the nearly exponential increase of traffic during the last decades. Adverse environmental impacts on infrastructure get more and more important as well. Therefore, it is important to determine how limited financial resources can be directed with an optimum pay-out. Often a decision has to be made whether existing structures have to be rebuilt or repaired based on the condition of the structures. The present study takes first steps towards the usage of low-frequency ultrasound as a tool to evaluate the road condition. The overall aim is to derive a prediction model for future road conditions. In order to better understand and interpret recorded wave fields simulations of elastic wave propagation in layered and scattering road models have been performed. The study combined investigations in the laboratory with field measurements. In a series of extensive laboratory tests with different asphalt mixtures characteristic wave properties have been derived. Travel time (resp. velocity) as important material parameter has been investigated for different wave types, different centre frequencies and at various temperatures. An investigation of the directivity of wave radiation in the heterogeneous asphalt bodies led to an estimate of the related disturbing influences. Based on the laboratory results field measurements were performed on a real road and the records were processed to identify layers, propagation speeds and attenuation. The results were verified by a series of simulations.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Bituminous material
KW - Road inspection
KW - Elastic waves
KW - Ultrasound
KW - Non-destructive testing
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345364
UR - https://www.ndt.net/?id=18421
SN - 1435-4934
VL - 20
IS - 11
SP - 1
EP - 9
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34536
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zoёga, Andreas
A1 - Kurz, J. H.
A1 - Oelschlägel, T.
A1 - Rohrschneider, A.
A1 - Müller, Christina
A1 - Pavlovic, Mato
A1 - Hintze, H.
A1 - Kanzler, D.
T1 - Investigations to introduce the probability of detection method for ultrasonic inspection of hollow axles at Deutsche Bahn
N2 - Currently at Deutsche Bahn (DB) ultrasonic inspections in maintenance procedures for wheelset axles with a bore hole are, to the greatest possible extent, carried out using automated ultrasonic inspection system. Although the acceptance levels are in accordance with DIN 27201 part 7, the testing results have shown in recent years that in the case of true indications, the effective defect sizes were far below the level of acceptance. Due to this experience it can be assumed that the automated ultrasonic inspection systems are testing substantially more sensitively than required. This increased sensitivity leads to an increase in false indications, generally resulting in the unnecessary demounting of wheelsets. In Research cooperation between Federal Institute for Materials Research and Testing (BAM) and DB the effective flaw detection sensitivity of existing automated ultrasonic inspection system will be determined and the true/false indication ratio optimised. Through systematic investigations with the Probability of Detection method on the existing automated ultrasonic inspection system the results could be directly applied to the optimisation of existing ultrasonic inspections of wheelset axles with a bore hole in maintenance procedures and the level of reliability can be considerably increased.
T2 - 19th World Conference on Non-Destructive Testing
CY - München, Germany
DA - 13.06.2016
KW - NDT
KW - Reliability
KW - POD
KW - Railway
KW - Axles
KW - UT
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375813
UR - http://www.ndt.net/article/wcndt2016/papers/we2g4.pdf
SP - id 19515, 1
EP - 8
AN - OPUS4-37581
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Trappe, Volker
A1 - Müller, Alexander
A1 - Hickmann, Stefan
T1 - Infinite life of CFRP evaluated non-destructively with X-ray-refraction topography in-situ mechanical loading
N2 - Carbon Fibre Reinforced Plastics (CFRP) are more and more used in modern civil aircrafts. These days the whole fuselage is made of this material (B787; A350). Due to strict certification standards the normal in-service loading gives a low stress level compared to the static and even the fatigue strength of the material. Hence CFRP are assumed to have an infinite life. To evaluate this assumption, fatigue tests on CFRP-specimens were performed up to 108 load cycles and the first inter-fibre failure was evaluated non-destructively by accompanying Xray-refraction topography. A tensile testing machine was integrated in a small angle X-ray scattering (SAXS) setup. X-ray refraction topography was performed while the CFRP samples were tensile loaded. This non-destructive technique enables the detection of micro-cracking and inter-fibre failure especially for CFRP. For Glass Fibre Reinforced Plastic (GFRP) X-ray refraction and in-situ loading has already been successfully used. The increase of inner surfaces due to inter fibre failure was measured as a function of the stress state. Fatigue tests were performed at and below the limit of inter-fibre failure strength. State of the art is to assume the failure of the samples under cyclic loading as the fatigue life. Accompanying non-destructive X-ray refraction measurements reflects the damage state and enables to trace its evolution even if the total failure of the specimens does not occur. This investigation technique is of high interest to give the engineer a design value of infinite life which is practically often reached due to knock down factors of certification standards. Finally the infinite life was found for cyclic fatigue loaded CFRP-samples even under high inter fibre transverse and shear loading investigated up to 108 load cycles.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - CFRP
KW - NDT
KW - Fatigue
KW - Damage evolution
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375015
UR - https://www.ndt.net/?id=19360
SN - 978-3-940283-78-8
VL - 2016
SP - 1
EP - 9
PB - DGZFP
CY - Berlin
AN - OPUS4-37501
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Spranger, Holger
A1 - Beckmann, Jörg
T1 - THz-SAFT Rekonstruktion von HDPE-Bauteilen
N2 - Obwohl THz-TDS-Systeme vielfältige Qualitätsparameter von Dielektrika ermitteln können, ist deren industrielle Nutzung im Bereich der zerstörungsfreien Bauteilprüfung noch nicht anerkannter Stand der Technik. Ein pragmatischer Weg, TDS-Systeme neben traditionellen Prüfverfahren zu etablieren, sind systematische Untersuchungen an Modellbauteilen, mit dem Ziel einer Methodenentwicklung zur zuverlässigen berührungslosen Prüfung von Dielektrika. Anhand von THz-TDS-Messungen an Polyethylen-Testkörpern mit künstlich eingebauten Fehlstellen werden anfänglich die Möglichkeiten der Laufzeitmessung zur Ermittlung von Tiefenlagen von Ungänzen in Testkörpern präsentiert. Im weitern Teil wird gezeigt, wie durch eine veränderte Versuchsdurchführung und Verwendung eines modifizierten SAFT-Rekonstruktions-Algorithmus Tomogramme berechnet werden können, in denen die künstlich eingebrachten Fehlstellen hinsichtlich ihrer Größe und Lage geometrisch richtig dargestellt werden.
T2 - 3. Fachseminar des FA MTHz Mikrowellen- und Terahertz-Prüftechnik in der Praxis
CY - Würzburg, Germany
DA - 05.04.2017
KW - THz
KW - THz-SAFT
KW - THz-TDS
KW - SAFT
KW - HDPE
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396883
SN - 978-3-940283-84-9
VL - 161
SP - 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-39688
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Ronneteg, U.
A1 - Grybäck, T.
A1 - Bertovic, Marija
A1 - Müller, Christina
A1 - Pavlovic, Mato
T1 - Safe for 1 million years – NDT matters!
N2 - The General Guidance in the Swedish regulations state that the safety assessment for a final repository for spent nuclear fuel should be 1 million years after closure. SKB developed the KBS-3 method, according to which the spent nuclear fuel is protected by three barriers. It is encapsulated in canisters with a diameter of 1 metre and a length of 5 metres. The canister consists of a cast iron insert surrounded by a 5 centimetre thick shell of copper. The canisters are disposed in the bedrock at a depth of about 500 meters surrounded by bentonite clay. In order to assess the safety over this extremely long period, an extensive quality control programme is applied to the canisters before deposit. In this programme, the use of
non-destructive testing (NDT) is vital. The safety assessment of the canister in turn places high demands on the coverage, detectability, and reliability of the applied NDT inspections of the canister parts, i.e. cast iron insert, copper base, tube and lid, and the copper friction stir welds (FSW). This paper presents the extensive full-scale inspection development programme that runs at the Canister Laboratory in Oskarshamn (Sweden). In order to fulfil the high demands, phased array ultrasonic inspection techniques are developed using practical trials aided by ultrasonic modelling. The techniques apply, for example, different frequencies, inspection angles, focus depths, and both longitudinal and shear waves. Increased inspection reliability of the FSW is achieved by applying digital X-ray technique using a 9 MeV linear accelerator and a line detector. To complete the coverage, complementary surface inspections methods, i.e. eddy current array, magnetic flux sensor techniques and magnetic particle inspection, are applied. The canister safety assessment was the driving force to include reliability studies during the NDT development. Initially, the technical reliability was considered, resulting in development of advanced POD models (probability of detection). In combination with human factors studies, these models were implemented as tools in the development of the NDT techniques. Human factors studies were also applied to improve the inspection procedures to be more user-friendly enabling reliable inspections.
T2 - 19th World Conference on Non-Destructive Testing
CY - München, Germany
DA - 13.06.2016
KW - NDT
KW - Reliability
KW - Spent nuclear fuel
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375785
UR - http://www.ndt.net/article/wcndt2016/papers/we4e4.pdf
SP - id 19464, 1
EP - 9
AN - OPUS4-37578
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, D.
A1 - Pavlovic, Mato
A1 - Bertovic, Marija
T1 - Zukünftige Möglichkeiten und Pflichten der zerstörungsfreien Prüfung
N2 - In unserer heutigen Zeit werden die Zwischenräume innerhalb der einzelnen Abteilungen eines Betriebs und zwischen einzelnen nationalen oder globalen Akteuren immer wichtiger: Produzierbarkeit vs. Wirtschaftlichkeit, Fortschritt vs. Nachhaltigkeit. Auch die zerstörungsfreie Prüfung (ZfP) – bisher hauptsächlich als Endkontrolle oder Wartungselement wahrgenommen – kann und sollte im Wandel der Digitalisierung und Industrie 4.0 einen neuen Stellenwert erhalten.
Die ZfP kann schon während der Konstruktion helfen, sichere und zuverlässige Produkte zu erstellen. Jedoch müssen dafür eine adäquate Informationskultur und die notwendigen Kennzahlen vorhanden sein. Objektive, probabilistische Kennzahlen (wie die POD - Auffindwahrscheinlichkeit) sind hierbei der Schlüssel. Diese müssen jedoch unbedingt an Prüfverfahren, Prüfgegenstand und Prüfbedingung angepasst werden, da sonst die gesamte Aussage in Frage zu stellen ist. Im Vortrag werden Beispiele aus der Anwendung gezeigt, die die Aussagekraft der Kennzahl aber auch die Sorgfalt, mit denen die einzelnen Aussagen genutzt werden, unterstrichen werden soll. Bewertung von Daten von realen Fehler, Anpassung an die Bruchfestigkeit und die Betrachtung von mehreren Prüfparametern am Beispiel der Bewertung von radiographischen, Ultraschall- und Wirbelstromprüfung werden in dem Vortrag gezeigt.
T2 - DGZfP-Jahrestagung 2017
CY - Koblenz, Germany
DA - 22.05.2017
KW - Zuverlässigkeit
KW - Zerstörungsfreie Prüfung
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404877
SN - 978-3-940283-85-6
VL - DGZfP-Berichtsband BB 162
SP - 1
EP - 6
AN - OPUS4-40487
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüllmann, Dino
A1 - Kohlhoff, Harald
A1 - Neumann, Patrick P.
ED - Bársony, I.
ED - Zolnai, Z.
ED - Battistig, G.
T1 - Embedded control of a PMSM servo drive without current measurements
N2 - A permanent-magnet synchronous motor (PMSM) servo drive for lightweight robotic platforms that have a high torque demand at low rotational speeds has been developed. First, a current-independent torque controller is derived and cascaded with a speed and position controller, while merely an encoder is used as a sensor device in combination with a speed estimator. Finally, the speed estimator output is compared to gyroscope measurements and the overall functioning is verified on a real system.
T2 - 30th Eurosensors Conference - Eurosensors 2016
CY - Budapest, Hungary
DA - 04.09.2016
KW - BLDC
KW - PMSM
KW - Motor control
KW - Servo drive
KW - Optical incremental encoder
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388973
DO - https://doi.org/10.1016/j.proeng.2016.11.487
SN - 1877-7058
VL - 168
SP - 1671
EP - 1675
PB - Elsevier B.V.
CY - Amsterdam, Netherlands
AN - OPUS4-38897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - McGrath, B.
A1 - Holstein, R.
A1 - Bertovic, Marija
T1 - How NDT companies can benefit from human factors knowledge
N2 - Ultrasonic phased array is, currently, the technology which is being applied as the solution to a lot of inspection problems. The perceived benefits are seen to be worth the outlay on equipment and specialised personnel. Yet, there is a source of knowledge, freely available, which can also deliver immediate benefits, through more reliable inspection results, and consequently increased client confidence, but which is largely ignored by the greater part of the NDT community. This talk will review the latest Human Factors knowledge and provide practical illustrations of how companies can use it to improve their competitive edge.
T2 - 19th World Conference on Non-Destructive Testing
CY - München, Germany
DA - 13.06.2016
KW - NDT
KW - Reliability
KW - Human factors
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375742
UR - http://www.ndt.net/article/wcndt2016/papers/tu4d3.pdf
SP - id 19532, 1
EP - 8
AN - OPUS4-37574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kotschate, Daniel
A1 - Gohlke, Dirk
A1 - Eisentraut, Mark
T1 - Reference block design for high resolution ultrasound immersion tank
N2 - In respect of modern approaches in material sciences and highly increased
requirements on materials on safety relevant components, quality management
and non-destructive testing reclaims a steadily increased meaning. The
destructive meaning of measuring the degree of purity is defined in DIN EN 10247
through metallurgical investigations, especially microsections.
For and comparable, but non-destructive testing due ultrasonic testing, the material
the SEP 1927 is a well-defined industry standard. A novel and alternative way
of reference block construction was focused by this work. The proposed amendments,
regarding the manufacturing and machining, are less time and cost consuming.
Verified by measurements the presented reference block fits the same acoustical
characteristics and the requirements of the guideline.
T2 - 19th World Conference on Non-Destructive Testing
CY - Munich, Germany
DA - 13.06.2016
KW - SEP 1927
KW - Degree of purity
KW - High resolution ultrasonic testing
KW - Immersion tank testing
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-368512
VL - 2016
SP - Paper X15, 1
EP - 4
AN - OPUS4-36851
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Armatys, Kamila
A1 - Miller, M.
T1 - Knudsen effusion mass spectrometry studies on metal halides performed in 1990-2014
N2 - Abstract Investigations on metal halide systems carried out by Knudsen effusion mass spectrometry in the period 1990-2014 are reviewed in the present paper.163 original papers were published focused on metal halides showing still considerable activity in this area. The fundamentals of the Knudsen effusion mass spectrometry method and thermodynamic background of the investigation are briefly reported. Data to the system studied, temperature ranges, Knudsen cell materials, vapor species identified in the equilibrium vapors and the thermodynamic properties obtained in the study are presented. The important issues of metal halide vaporization studies are briefly discussed and commented. The studies of the vaporization of metal halogens by Knudsen effusion mass spectrometry aimed firstly atthe determination of gaseous complexes species in the vapor and determination of its thermodynamic data like sublimation enthalpy etc. and secondly at the determination of negative ions formation and various ion-molecule equilibria reactions of metal halide systems. Many of the studied materials have a crucial role for modern technologies, for example metal halide lamps, hot corrosion caused by halide salts, phosphorus recovery technologies or gas assisted separation of lanthanides. The investigation of such systems gives information on mechanisms of vaporization, volatility of the systems under various conditions (temperature, pressure etc.), reactivity, thermal stability, resistance etc. that could be further applied for various calculations and to predict the behavior of various components under various technological aspects.
KW - Metal halides
KW - Knudsen Effusion Mass Spectrometry (KEMS)
KW - HTMS
KW - Thermochemistry
KW - High temperature
KW - Vaporization
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357126
SN - 2349-7092
VL - 3
IS - 1
SP - 68
EP - 93
PB - The Pharmaceutical and Chemical Journal
CY - Kundlawala, India
AN - OPUS4-35712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andres, S.
A1 - Hansen, Ulf
A1 - Niemann, B.
A1 - Palavinskas, R.
A1 - Lampen, A.
T1 - Determination of the isoflavone composition and estrogenic activity of commercial dietary supplements based on soy or red clover
N2 - Dietary supplements high in isolated isoflavones are commercially available for human consumption primarily to alleviate menopausal symptoms in women. The isoflavone composition, quantity and importantly their estrogenic potency are poorly standardised and can vary considerably between different products. The aim of this study was to analyse the isoflavone composition of 11 dietary supplements based on soy or red clover using the HPLC/MS/MS technique. Furthermore, we investigated the transactivational potential of the supplements on the estrogen receptors (ER), ERα and ERβ, performing luciferase reporter gene assays. As expected, we found that the isoflavone composition varies between different products. The measured total isoflavone contents in various supplements were mostly comparable to those claimed by the manufacturers in their product information. However expressing the isoflavone content as isoflavone aglycone equivalents, soy-based supplements had a clearly lower quantity compared to the manufacturer information. All supplements transactivated more or less ERα and ERβ with a preference for ERβ. The transactivational efficiency exceeded partly the maximal 17β-estradiol induced ER activation. While the different soy-based supplements revealed similar transactivation potential to both ERs, red clover-based supplements differed considerably. We conclude that different commercial dietary supplements based on soy or red clover vary in their isoflavone composition and quantity. They are estrogenically active, although especially the red clover-based supplements show considerable differences in their estrogenic potential to ERα and ERβ. Thus, different isoflavone-rich products cannot be necessarily compared regarding possible biological effects.
KW - estrogenic activity
KW - HPLC/MS/MS technique
KW - Estrogen receptor (ER)
KW - nutritional supplements
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357093
DO - https://doi.org/10.1039/C5FO00308C
IS - 6
SP - 2017
EP - 2025
PB - The Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-35709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Birgit Angelika
A1 - Ziemann, M. A
A1 - Pentzien, Simone
A1 - Gabsch, T.
A1 - Koch, W.
A1 - Krüger, Jörg
T1 - Technical analysis of a Central Asian wall painting detached from a Buddhist cave temple on the northern Silk Road
N2 - A great number of Central Asian wall paintings, archeological materials, architectural fragments, and textiles, as well as painting fragments on silk and paper, make up the so called Turfan Collection at the Asian Art Museum in Berlin. The largest part of the collection comes from the Kucha region, a very important cultural center in the third to ninth centuries. Between 1902 and 1914, four German expeditions traveled along the northern Silk Road. During these expeditions, wall paintings were detached from their original settings in Buddhist cave complexes. This paper reports a technical study of a wall painting, existing in eight fragments, from the Buddhist cave no. 40 (Ritterhöhle). Its original painted surface is soot blackened and largely illegible. Grünwedel, leader of the first and third expeditions, described the almost complete destruction of the rediscovered temple complex and evidence of fire damage. The aim of this case study is to identify the materials used for the wall paintings. Furthermore, soot deposits as well as materials from conservation interventions were of interest. Non-invasive analyses were preferred but a limited number of samples were taken to provide more precise information on the painting technique. By employing optical and scanning electron microscopy, energy dispersive X-ray spectroscopy, micro X-ray fluorescence spectroscopy, X-ray diffraction analysis, and Raman spectroscopy, a layer sequence of earthen render, a ground layer made of gypsum, and a paint layer containing a variety of inorganic pigments were identified.
KW - Wall paintings
KW - Central Asia
KW - Silk Road
KW - Pigments
KW - Microscopy
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-357297
DO - https://doi.org/10.1179/2047058414Y.0000000152
VL - 61
IS - 2
SP - 113
EP - 122
PB - Routledge Taylor & Francis Group
CY - London
AN - OPUS4-35729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Franz-Georg
A1 - Holm, Olaf
T1 - Reduction of natural resource use by improving resource efficiency
N2 - In 2011, the German Association of Engineers (VDI) started working on a set of guidelines dealing with the improvement of resource efficiency. These guidelines represent a framework that defines resource efficiency and outlines proposals for the producing industry. A special guideline for small and medium-sized enterprises (SMEs) is included as well as guidelines on methodologies for evaluating resource use indicators, such as the cumulative raw material demand of products and production systems. The work on resource use indicators is still in progress. The evaluation of raw materials expenditure will include water, soil and land use. The model will include the availability of raw materials (criticality). Improving resource efficiency at the end-of-life stage is illustrated in this paper by the example of materials recovery from waste, here from residues out of municipal solid waste incineration (MSWI). With mechanical treatment valuable materials like ferrous and non-ferrous metals and secondary construction material can be extracted from MSWI bottom ash. The potential contribution on the resource efficiency is discussed.
KW - Resource efficiency
KW - Raw material equivalent
KW - Mechanical treatment
KW - Bottom ash
KW - Waste incineration
KW - Secondary raw materials
KW - Product life cycle
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-356490
UR - http://www.hrpub.org/journals/jour_archive.php?id=62&iid=877
DO - https://doi.org/10.13189/ ujms.2016.040302
SN - 2331-6691
SN - 2331-6705
VL - 4
IS - 3
SP - 54
EP - 59
PB - Horizon Research Publishing
CY - Alhambra, CA, USA
AN - OPUS4-35649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Grohmann, Maria
A1 - Müller, Sabine
A1 - Niederleithinger, Ernst
T1 - Reverse time migration: Introduction of a new imaging technique for ultrasonic measurements in civil engineering
N2 - Ultrasonic echo testing is widely used in non-destructive testing in civil engineering to investigate concrete structures, to measure thickness, and to locate and characterise built-in components or inhomogeneities. Currently, synthetic aperture focusing techniques are mostly used for imaging. These algorithms are highly developed but have some limitations. For example, it is not possible to image the lower boundary of built-in components like tendon ducts or vertical reflectors. We adopted reverse time migration for non-destructive testing in civil engineering in order to improve the imaging of complicated structures in concrete. By using the entire wavefield, including waves reflected more than once, there are fewer limitations compared to synthetic aperture focusing technique algorithms. As a drawback, the required computation is significantly higher than that for the techniques currently used. Simulations for polyamide and concrete structures showed the potential for non-destructive testing. The simulations were followed by experiments at a polyamide specimen. Here, having acquired almost noise-free measurement data to test the algorithm, we were able to determine the shape and size of boreholes with sufficient accuracy. After these successful tests, we performed experiments at a reinforced concrete foundation slab. We obtained information from the data by reverse time migration, which was not accessible by traditional imaging. The imaging of the location and structure of the lower boundary of the concrete foundation slab was improved. Furthermore, vertical reflectors inside the slab were imaged clearly, and more flaws were found. It has been shown that reverse time migration is a step forward in ultrasonic testing in civil engineering.
T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering
CY - Berlin, Germany
DA - 15.09.2015
KW - Ultrasound
KW - Imaging
KW - Reverse time migration
KW - Reflection seismics
KW - Concrete
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345406
SN - 1435-4934
SP - 1
EP - 10
PB - Technische Universität Berlin / Bundesanstalt für Materialforschung und -prüfung
AN - OPUS4-34540
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Douma, J.
A1 - Niederleithinger, Ernst
A1 - Snieder, R.
T1 - Improved focusing using deconvolution within a concrete block
N2 - Time reversal techniques are used in ocean acoustics, medical imaging and non-destructive evaluation to backpropagate recorded signals to the source of origin. We demonstrate experimentally a technique which improves the temporal focus achieved at the source location. The experiment consists of propagating a signal from a transducer within a concrete block to a single receiver on the surface, and then applying time reversal or deconvolution to focus the energy back at the source location. The results show that we are able to generate a focus in time at the correct location. The proposed method is simple and proven to be robust. Additionally, its costs are negligible due to deconvolution being a preprocessing step to the recorded data. The technique can be applied for detailed investigation of the source mechanisms (e. g. cracks) but also for monitoring purposes.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Ultrasonics
KW - Acoustic emission
KW - Time reversal
KW - Deconvolution
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337953
UR - http://www.ndt.net/article/dgzfp2014/papers/di2c2.pdf
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Di.2.C.2, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-33795
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Müller, Sabine
A1 - Niederleithinger, Ernst
T1 - Anwendung der Reverse Time Migration auf Ultraschall-Echo-Messungen in der zerstörungsfreien Prüfung im Bauwesen
N2 - Ultraschall-Echo-Messungen dienen im Bauwesen zur Dickenbestimmung von Bauteilen sowie der Lokalisierung und Charakterisierung von Einbauteilen, Einlagerungen und anderen Inhomogenitäten. Zur Rekonstruktion werden bisher Abbildungsverfahren wie z.B. 3D-SAFT genutzt. Diese setzen aber voraus, dass direkte Reflexionen am Abbildungsobjekt erfolgen. Deshalb können keine zuverlässigen Aussagen über den Durchmesser von eingebauten Spannkanälen oder z. B. Seitenkanten von Objekten getroffen werden.
Ziel laufender Forschungsarbeiten ist es, die Abbildungsqualität zu verbessern.
Mit der aus der Geophysik stammenden Reverse Time Migration, die bereits häufig in der Erdölexploration genutzt wird, lassen sich auch steilere Strukturen über 70° abbilden und somit auch die Unterseite von Einbauten oder Stufen in Bauteilen darstellen.
Um die Leistungsfähigkeit des Algorithmus für die zerstörungsfreie Prüfung zu untersuchen, wurden verschiedene Simulationsrechnungen durchgeführt. Dabei wurden typische Prüfprobleme unterschiedlicher Komplexität zunächst in Polyamid nachgestellt. Die Schwerpunkte lagen bei der Darstellung senkrechter Grenzflächen und Hohlstellen. Die Rechnungen dienten neben der Evaluierung und Optimierung des Verfahrens auch der Planung von Experimenten an Probekörpern mit verschiedenen Einbauten.
Die Simulationsergebnisse wurden an einem dem synthetischen Modell entsprechenden Polyamidprobekörper überprüft, an dem rauscharme Ultraschalldaten aufgenommen werden konnten. In einer Messreihe wurde in den Probekörper eine Bohrung eingebracht und schrittweise vergrößert. Mit diesen Messungen konnte die Leistungsfähigkeit der Reverse Time Migration auch an realen Ultraschalldaten nachgewiesen werden. Untersuchungen mit an Beton aufgenommenen Ultraschalldaten werden folgen.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Ultraschall
KW - Reverse Time Migration
KW - Zerstörungsfreie Prüfung
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-319311
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Di.1.C.4, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-31931
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Niederleithinger, Ernst
A1 - Wolf, Julia
A1 - Mielentz, Frank
A1 - Wiggenhauser, Herbert
A1 - Pirskawetz, Stephan
T1 - Embedded ultrasonic transducers for active and passive concrete monitoring
N2 - Recently developed new transducers for ultrasonic transmission, which can be embedded right into concrete, are now used for non-destructive permanent monitoring of concrete. They can be installed during construction or thereafter. Large volumes of concrete can be monitored for changes of material properties by a limited number of transducers. The transducer design, the main properties as well as installation procedures are presented. It is shown that compressional waves with a central frequency of 62 kHz are mainly generated around the transducer's axis. The transducer can be used as a transmitter or receiver. Application examples demonstrate that the transducers can be used to monitor concrete conditions parameters (stress, temperature,
) as well as damages in an early state or the detection of acoustic events (e.g., crack opening). Besides application in civil engineering our setups can also be used for model studies in geosciences.
KW - Ultrasound
KW - Transmission
KW - Concrete
KW - Damages
KW - Cracks
KW - Stress
KW - Monitoring
KW - Acoustic emission
KW - Transducers
KW - Coda wave interferometry
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-345632
DO - https://doi.org/10.3390/s150509756
SN - 1424-8220
VL - 15
IS - 5
SP - 9756
EP - 9772
PB - MDPI
CY - Basel
AN - OPUS4-34563
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schukar, Vivien
A1 - Kusche, Nadine
A1 - Kalinka, Gerhard
A1 - Habel, Wolfgang
T1 - Field deployable fiber bragg grating strain patch for long-term stable health monitoring applications
N2 - A fiber Bragg grating (FBG) strain patch specially adapted for long-term and high-strain applications has been developed and characterized. The design concept for the patch is based on a glass-fiber reinforced plastic (gfrp) carrier material. The developed concept for the FBG integration into the carrier material was derived from reliable integration procedure of FBG sensors into composite structures. The patches' temperature sensitivity, strain gauge factor, fiber–matrix interface adhesion and fatigue behavior were characterized. As a result, FBG strain patches with linear temperature and strain behavior, as well as excellent fatigue resistance, were developed and can be used as part of a monitoring system for advanced composite materials in aerospace structures or wind turbine power plants.
KW - Fiber Bragg grating
KW - Patch
KW - Strain gauge factor
KW - Temperature sensitivity
KW - Push-out test
KW - Validation
KW - Fatigue behavior
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-276271
DO - https://doi.org/10.3390/app3010039
SN - 2076-3417
VL - 3
IS - 1
SP - 39
EP - 54
PB - MDPI
CY - Basel
AN - OPUS4-27627
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiggenhauser, Herbert
A1 - Niederleithinger, Ernst
T1 - Innovative ultrasonic techniques for inspection and monitoring of large concrete structures
N2 - Ultrasonic echo and transmission techniques are used in civil engineering on a regular basis. New sensors and data processing techniques have lead to many new applications in the structural investigation as well as quality control. But concrete structures in the nuclear sector have special features and parameters, which pose problems for the methods and instrumentation currently available, e.g. extreme thickness, dense reinforcement, steel liners or special materials. Several innovative ultrasonic techniques have been developed to deal with these issues at least partly in lab experiments and pilot studies. Modern imaging techniques as multi-offset SAFT have been used e. g. to map delaminations. Thick concrete walls have successfully been inspected, partly through a steel liner. Embedded ultrasonic sensors have been designed which will be used in monitoring networks of large concrete structures above and below ground. In addition, sensitive mathematical methods as coda wave interferometry have been successfully evaluated to detect subtle changes in material properties. Examples of measurements and data evaluation are presented.
KW - Automated scanning systems
KW - Multi-Offset Array
KW - Enhanced Imaging
KW - Embedded ultrasonic sensors
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-290513
DO - https://doi.org/10.1051/epjconf/20135604004
SN - 2100-014X
VL - 56
SP - 04004-1
EP - 04004-9
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-29051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hansen, Ulf
A1 - Thünemann, Andreas
T1 - Characterization of silver nanoparticles in cell culture medium containing fetal bovine serum
N2 - Nanoparticles are being increasingly used in consumer products worldwide, and their toxicological effects are currently being intensely debated. In vitro tests play a significant role in nanoparticle risk assessment, but reliable particle characterization in the cell culture medium with added fetal bovine serum (CCM) used in these tests is not available. As a step toward filling this gap, we report on silver ion release by silver nanoparticles and on changes in the particle radii and in their protein corona when incubated in CCM. Particles of a certified reference material, p1, and particles of a commercial silver nanoparticle material, p2, were investigated. The colloidal stability of p1 is provided by the surfactants polyethylene glycol-25 glyceryl trioleate and polyethylene glycol-20 sorbitan monolaurate, whereas p2 is stabilized by polyvinylpyrrolidone. Dialyses of p1 and p2 reveal that their silver ion release rates in CCM are much larger than in water. Particle characterization was performed with asymmetrical flow field-flow fractionation, small-angle X-ray scattering, dynamic light scattering, and electron microscopy. p1 and p2 have similar hydrodynamic radii of 15 and 16 nm, respectively. The silver core radii are 9.2 and 10.2 nm. Gel electrophoresis and subsequent peptide identification reveal that albumin is the main corona component of p1 and p2 after incubation in CCM that consists of Dulbecco's modified Eagle medium with 10% fetal bovine serum added.
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-335510
DO - https://doi.org/10.1021/acs.langmuir.5b00687
SN - 0743-7463
SN - 1520-5827
VL - 31
IS - 24
SP - 6842
EP - 6852
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-33551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neffe, A.T.
A1 - Von Ruesten-Lange, M.
A1 - Braune, S.
A1 - Lützow, K.
A1 - Roch, T.
A1 - Richau, K.
A1 - Krüger, A.
A1 - Becherer, T.
A1 - Thünemann, Andreas
A1 - Jung, F.
A1 - Haag, R.
A1 - Lendlein, A.
T1 - Multivalent grafting of hyperbranched oligo- and polyglycerols shielding rough membranes to mediate hemocompatibility
N2 - Hemocompatible materials are needed for internal and extracorporeal biomedical applications, which should be realizable by reducing protein and thrombocyte adhesion to such materials. Polyethers have been demonstrated to be highly efficient in this respect on smooth surfaces. Here, we investigate the grafting of oligo- and polyglycerols to rough poly(ether imide) membranes as a polymer relevant to biomedical applications and show the reduction of protein and thrombocyte adhesion as well as thrombocyte activation. It could be demonstrated that, by performing surface grafting with oligo- and polyglycerols of relatively high polydispersity (>1.5) and several reactive groups for surface anchoring, full surface shielding can be reached, which leads to reduced protein adsorption of albumin and fibrinogen. In addition, adherent thrombocytes were not activated. This could be clearly shown by immunostaining adherent proteins and analyzing the thrombocyte covered area. The presented work provides an important strategy for the development of application relevant hemocompatible 3D structured materials.
KW - Nanotechnology
KW - thrombocyte adhesion
KW - biomedical applications
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-308196
DO - https://doi.org/10.1039/c4tb00184b
SN - 2050-750X
SN - 2050-7518
VL - 2
IS - 23
SP - 3626
EP - 3635
PB - Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-30819
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästner, Claudia
A1 - Thünemann, Andreas
T1 - Catalytic reduction of 4-nitrophenol using silver
nanoparticles with adjustable activity
N2 - We report on the development of ultra-small core-shell silver nanoparticles synthesized by an up-scaled modification of the polyol process. It is foreseen to use these thoroughly characterized particles as reference material to compare the catalytic and biological properties of functionalized silver nanoparticles. Small-angle X-ray scattering (SAXS) analysis reveal a narrow size distribution of the silver cores with a mean radius of RC = 3.0 nm and a distribution width of 0.6 nm. Dynamic light scattering (DLS) provides a hydrodynamic radius of RH = 10.0 nm and a PDI of 0.09. The particles’ surface is covered with poly(acrylic acid) (PAA) forming a shell with a thickness of 7.0 nm, which provides colloidal stability lasting for more than six months at ambient conditions. The PAA can be easily exchanged by biomolecules to modify the surface functionality. Replacements of PAA with glutathione (GSH) and bovine serum albumin (BSA) have been performed as examples. We demonstrate that the particles effectively catalyze the reduction of 4-nitrophenol to 4-aminophenol with sodium borohydride. With PAA as stabilizer, the catalytic activity of 436 ± 24 L g⁻¹ s⁻¹ is the highest reported in literature for silver nanoparticles. GSH and BSA passivate the surface substantially resulting in a catalytic activity of 77.6 ± 0.9 and 3.47 ± 0.50 L g⁻¹ s⁻¹, respectively.
KW - Silver nanoparticles
KW - Catalysis
KW - Reference material
KW - Protein coating
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370655
DO - https://doi.org/10.1021/acs.langmuir.6b01477
SN - 0743-7463
SN - 1520-5827
VL - 32
IS - 29
SP - 7383
EP - 7391
AN - OPUS4-37065
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szczerba, Wojciech
A1 - Schott, M.
A1 - Riesemeier, Heinrich
A1 - Thünemann, Andreas
A1 - Kurth, D.G.
T1 - Thermally induced structural rearrangement of the Fe(II) coordination geometry in metallo-supramolecular polyelectrolytes
N2 - Rigid rod-type metallo-supramolecular coordination polyelectrolytes with Fe(II) centres (Fe-MEPEs) are produced via the self-assembly of the ditopic ligand 1,4-bis(2,2':6',2''-terpyridine-4'-yl)benzene (tpy-ph-tpy) and Fe(II) acetate. Fe-MEPEs exhibit remarkable electrochromic properties; they change colour from blue to transparent when an electric potential is applied. This electrochemical process is generally reversible. The blue colour in the ground state is a result of a metal-to-ligand charge transfer at the Fe(II) centre ion in a quasi-octahedral geometry. When annealed at temperatures above 100 °C, the blue colour turns into green and the formerly reversible electrochromic properties are lost, even after cooling down to room temperature. The thermally induced changes in the Fe(II) coordination sphere are investigated in situ during annealing of a solid Fe-MEPE using X-ray absorption fine structure (XAFS) spectroscopy. The study reveals that the thermally induced transition is not accompanied by a redox process at the Fe(II) centre. From the detailed analysis of the XAFS spectra, the changes are attributed to structural changes in the coordination sphere of the Fe(II) site. In the low temperature state, the Fe(II) ion rests in a quasi-octahedral coordination environment surrounded by six nitrogen atoms of the pyridine rings. The axial Fe–N bond length is 1.94 Å, while the equatorial bond length amounts to 1.98 Å. In the high temperature state, the FeN6-site exhibits a distortion with the axial Fe–N bonds being shortened to 1.88 Å and the equatorial Fe–N bonds being elongated to 2.01 Å.
KW - Metallo-supramolecular polyelectrolytes
KW - Electrochromism
KW - XANES
KW - EXAFS
KW - Local structure
KW - Thermal stability
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-317331
DO - https://doi.org/10.1039/c4cp01187b
SN - 1463-9076
SN - 1463-9084
VL - 16
IS - 36
SP - 19694
EP - 19701
PB - The Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-31733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strangfeld, Christoph
A1 - Wiehle, Philipp
T1 - Closure of "Quantification of moisture content in earth block masonry under natural climatic conditions"
N2 - In January 2025, the research paper “Quantification of moisture content in earth block masonry under natural climatic conditions” was published in Construction and Building Materials. The central theme was the moisture monitoring of a masonry wall made of unstabilised earth blocks over a period of around 18 months. The experimental results were compared to WUFI simulations, and the moisture transport in layered wall constructions was eventually studied in WUFI. Prof. Janssen discussed this publication in Construction and Building Materials. He raised concerns about the experiments and modelling of moisture transport. In this closure, the capillary adsorption coefficient was recalculated, and deviations from the initial value were quantified. Sensitivity analyses were conducted in WUFI to evaluate the influence of different water vapour resistances and water adsorption coefficients. The resulting moisture transport was then compared to material moisture profiles measured using 1H NMR relaxometry. Finally, the water adsorption behaviour of different earth materials is discussed in respect to material moisture and corresponding relative humidity.
KW - Earth masonry
KW - Moisture transport
KW - Capillary water absorption
KW - Embedded humidity sensors
KW - NMR
KW - WUFI
KW - Material moisture
KW - Water vapour diffusion resistance
KW - Sustainable building materials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637569
DO - https://doi.org/10.1016/j.conbuildmat.2025.142552
SN - 0950-0618
VL - 491
SP - 1
EP - 6
PB - Elsevier Ltd.
AN - OPUS4-63756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, S.
A1 - McMahon, Dino Peter
A1 - Lim, K.S.
A1 - Pull, C.D.
A1 - Clark, S.J.
A1 - Paxton, R.J.
A1 - Osborne, J.L.
T1 - So near and yet so far: harmonic radar reveals reduced homing ability of Nosema infected honeybees
N2 - Pathogens may gain a fitness advantage through manipulation of the behaviour of their hosts. Likewise, host behavioural changes can be a defence mechanism, counteracting the impact of pathogens on host fitness. We apply harmonic radar technology to characterize the impact of an emerging pathogen - Nosema ceranae (Microsporidia) - on honeybee (Apis mellifera) flight and orientation performance in the field. Honeybees are the most important commercial pollinators. Emerging diseases have been proposed to play a prominent role in colony decline, partly through sub-lethal behavioural manipulation of their hosts. We found that homing success was significantly reduced in diseased (65.8%) versus healthy foragers (92.5%). Although lost bees had significantly reduced continuous flight times and prolonged resting times, other flight characteristics and navigational abilities showed no significant difference between infected and non-infected bees. Our results suggest that infected bees express normal flight characteristics but are constrained in their homing ability, potentially compromising the colony by reducing its resource inputs, but also counteracting the intra-colony spread of infection. We provide the first high-resolution analysis of sub-lethal effects of an emerging disease on insect flight behaviour. The potential causes and the implications for both host and parasite are discussed.
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-328827
DO - https://doi.org/10.1371/journal.pone.0103989
SN - 1932-6203
VL - 9
IS - 8
SP - e103989, 1
EP - 15
PB - PubMed Central
AN - OPUS4-32882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirtschin, Nikolaus
A1 - Pretsch, Thorsten
T1 - Designing temperature-memory effects in semicrystalline polyurethane
N2 - Temperature-memory polymers are able to generate a substantial mechanical response when heated above the temperature, at which a preceding deformation was carried out. Here we show how to design the temperature-memory effect (TME) by thermomechanical treatment. As a model polymer, phase segregated poly(ester urethane) (PEU) containing crystallizable segments of poly(1,4-butylene adipate) (PBA) was used. For programming, strain elongation was applied at temperatures within the PBA melting transition area, before temperature holding, unloading and cooling were carried out. Upon heating under stress-free or constant strain recovery conditions, precisely set temperature-memory onsets could be witnessed. Most importantly, strain fixities and recoverabilities the same as maximum recovery stresses turned out to be controllable by strain rate and temperature holding time after deformation, while transition temperatures remained largely unaffected. The tailoring of thermoresponsiveness was structurally enabled by different PBA crystallinities in the programmed state as verified by wide-angle X-ray scattering (WAXS). The reported studies intend to design TMEs in semicrystalline polyurethanes according to user-defined needs to make this technology broadly applicable.
KW - Poly(ester urethane)
KW - Shape memory polymer
KW - Temperature-memory effect
KW - Thermo-responsiveness
KW - Temperature-memory polymer
KW - Programming
KW - Thermomechanical properties
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-332856
DO - https://doi.org/10.1039/c5ra05492c
SN - 2046-2069
VL - 5
IS - 57
SP - 46307
EP - 46315
PB - RSC Publishing
CY - London
AN - OPUS4-33285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ehlert, Christopher
A1 - Unger, Wolfgang
A1 - Saalfrank, P.
T1 - C K-edge NEXAFS spectra of graphene with physical and chemical defects: a study based on density functional theory
N2 - Recently, C K-edge Near Edge X-ray Absorption Fine Structure (NEXAFS) spectra of graphite (HOPG) surfaces have been measured for the pristine material, and for HOPG treated with either bromine or krypton plasmas (Lippitz et al., Surf. Sci., 2013, 611, L1). Changes of the NEXAFS spectra characteristic for physical (krypton) and/or chemical/physical modifications of the surface (bromine) upon plasma treatment were observed. Their molecular origin, however, remained elusive. In this work we study by density functional theory, the effects of selected point and line defects as well as chemical modifications on NEXAFS carbon K-edge spectra of single graphene layers. For Br-treated surfaces, also Br 3d X-ray Photoelectron Spectra (XPS) are simulated by a cluster approach, to identify possible chemical modifications. We observe that some of the defects related to plasma treatment lead to characteristic changes of NEXAFS spectra, similar to those in experiment. Theory provides possible microscopic origins for these changes.
KW - Graphene
KW - NEXAFS
KW - Spectrum simulation
KW - Density functional theory
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-309658
DO - https://doi.org/10.1039/c4cp01106f
SN - 1463-9076
SN - 1463-9084
VL - 16
IS - 27
SP - 14083
EP - 14095
PB - The Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-30965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cordeiro, F.
A1 - Llorente-Mirandes, T.
A1 - López-Sánchez, J.F.
A1 - Rubio, R.
A1 - Sánchez-Agullo, A.
A1 - Raber, G.
A1 - Scharf, Holger
A1 - Vélez, D.
A1 - Devesa, V.
A1 - Fiamegos, Y.
A1 - Emteborg, H.
A1 - Seghers, J.
A1 - Robouch, P.
A1 - De la Calle, M.B.
T1 - Determination of total cadmium, lead, arsenic, mercury and inorganic arsenic in mushrooms: outcome of IMEP-116 and IMEP-39
N2 - The Institute for Reference Materials and Measurements (IRMM) of the Joint Research Centre (JRC), a Directorate General of the European Commission, operates the International Measurement Evaluation Program (IMEP). IMEP organises inter-laboratory comparisons in support of European Union policies. This paper presents the results of two proficiency tests (PTs): IMEP-116 and IMEP-39, organised for the determination of total Cd, Pb, As, Hg and inorganic As (iAs) in mushrooms. Participation in IMEP-116 was restricted to National Reference Laboratories (NRLs) officially appointed by national authorities in European Union member states. IMEP-39 was open to all other laboratories wishing to participate. Thirty-seven participants from 25 countries reported results in IMEP-116, and 62 laboratories from 36 countries reported for the IMEP-39 study. Both PTs were organised in support to Regulation (EC) No. 1881/2006, which sets the maximum levels for certain contaminants in food. The test item used in both PTs was a blend of mushrooms of the variety shiitake (Lentinula edodes). Five laboratories, with demonstrated measurement capability in the field, provided results to establish the assigned values (Xref). The standard uncertainties associated to the assigned values (uref) were calculated by combining the uncertainty of the characterisation (uchar) with a contribution for homogeneity (ubb) and for stability (ust), whilst uchar was calculated following ISO 13528. Laboratory results were rated with z- and zeta (ζ)-scores in accordance with ISO 13528. The standard deviation for proficiency assessment, σp, ranged from 10% to 20% depending on the analyte. The percentage of satisfactory z-scores ranged from 81% (iAs) to 97% (total Cd) in IMEP-116 and from 64% (iAs) to 84% (total Hg) in IMEP-39.
KW - Inorganic arsenic
KW - Trace elements
KW - Mushrooms
KW - Proficiency test
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-326092
DO - https://doi.org/10.1080/19440049.2014.966336
SN - 1944-0057
SN - 1944-0049
VL - 32
IS - 1
SP - 54
EP - 67
PB - Taylor & Francis
CY - London [u.a.]
AN - OPUS4-32609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hemmann, Felix
A1 - Jäger, Christian
A1 - Kemnitz, E.
T1 - Comparison of acidic site quantification methods for a series of nanoscopic aluminium hydroxide fluorides
N2 - Quantitative determination of acidic surface sites is highly important for the characterization of solid acids because the activity of a catalyst is often related to the concentration of these sites. A recently developed method using 15N Nuclear Magnetic Resonance spectroscopy (NMR) for the quantification of acidic Lewis and Brønsted sites has been tested for a series of nanoscopic aluminum hydroxide fluorides. Comparison with other methods for the quantitative determination of acidic sites shows that this 15N NMR quantification method is a promising technique for the comprehensive investigation of acidic sites. Three different acidic sites, one Brønsted and two Lewis sites, can be distinguished by their 15N chemical shifts of pyridine and simultaneously quantified under conditions corresponding to catalytic reaction conditions. Determination of the individual concentrations of acidic sites allows further insight into the catalytic process. It was found that the concentration of Brønsted sites correlates with catalyzed conversion of citronellal to isopulegol in the investigated series of catalysts. Additionally, investigations indicate that one of the Lewis sites become blocked during the reaction of citronellal.
KW - Solid acids
KW - TOF
KW - NH3-TPD
KW - Progressive catalyst poisoning
KW - FTIR
KW - Quantitative NMR
KW - Solid state NMR
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-323280
DO - https://doi.org/10.1039/c4ra09477h
SN - 2046-2069
VL - 4
IS - 100
SP - 56900
EP - 56909
PB - RSC Publishing
CY - London
AN - OPUS4-32328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiggenhauser, Herbert
A1 - Naus, D.J.
T1 - NDE of thick and highly reinforced concrete structures: state of the art
N2 - The objective of the report is to present the state-of-the art of non-destructive testing methods and technologies for the inspection of thick, heavily-reinforced structures, (e.g. found in nuclear power plants). Wall thicknesses can be in excess of one meter and the structures often have increased steel reinforcement density. The accessibility for any testing method may be limited due to the presence of liners and other components such as cast-in-place items. Testing methods have to provide solutions for tasks such as locating failure (inclusions, corrosion, voids, delaminations) in the structures or the assessment of the condition of the structure in general.
KW - Non-destructuive testing
KW - Inspection
KW - Nuclear power plant
KW - State-of-the-art
KW - Highly reinforced concrete
KW - NDE
KW - Engineering
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-329674
DO - https://doi.org/10.1016/j.proeng.2014.11.055
SN - 1877-7058
VL - 86
SP - 420
EP - 426
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-32967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosemann, Paul
A1 - Müller, C.
A1 - Baumann, O.
A1 - Modersohn, W.
A1 - Halle, T.
T1 - Influence of the post-weld surface treatment on the corrosion resistance of the duplex stainless steel 1.4062
N2 - The duplex stainless steel 1.4062 (X2CrNiN22-2) is used as alternative material to austenitic stainless steels in the construction industry. The corrosion resistance of welded seams is influenced by the base material, the weld filler material, the welding process and also by the final surface treatment. The scale layer next to the weld seam can be removed by grinding, pickling, electro-polished or blasting depending on the application and the requested corrosion resistance. Blasted surfaces are often used in industrial practice due to the easier and cheaper manufacturing process compared to pickled or electro-polished surfaces. Furthermore blasting with corundum-grain is more effective than blasting with glass-beads which also lower the process costs. In recent years, stainless steel surfaces showed an unusually high susceptibility to pitting corrosion after grinding with corundum. For this reason, it is now also questioned critically whether the corrosion resistance is influenced by the applied blasting agent. This question was specifically investigated by comparing grinded, pickled, corundum-grain- and glass-bead-blasted welding seams. Results of the SEM analyses of the blasting agents and the blasted surfaces will be presented and correlated with the different performed corrosion tests (potential measurement, KorroPad-test and pitting potential) on welding seams with different surface treatments.
T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
DA - 16.03.2017
KW - Corrosion resistance
KW - Welding
KW - Duplex stainless steels
KW - Pitting corrosion
KW - Surface treatment
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395374
DO - https://doi.org/10.1088/1757-899X/181/1/012019
SN - 1757-899X
SN - 1757-8981
VL - 181
IS - Conference 1
SP - Article UNSP 012019, 1
EP - 9
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-39537
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ecker, Melanie
A1 - Pretsch, Thorsten
T1 - Novel design approaches for multifunctional information carriers
N2 - Two design approaches for multifunctional information carriers are introduced. In the first one, quick response (QR) code carriers, which were composed of poly(ester urethane) (PEU) and microencapsulated thermochromic pigments (T-PIGs), differing in color and color switching temperature (CST), were prepared. The obtained material systems exhibited machine-readable QR codes at 23 °C and a two-stage decolorization when heated, culminating in unreadable QR codes at temperatures above the highest CST of the employed T-PIGs. In the second scenario, information carriers were sealed with a dark, thermochromic PEU layer. As a result, the QR codes were hidden at 23 °C and became readable upon heating due to color fading. Beyond the characterization of the employed components, preparation methods, functionality analyses and durability investigations are reported. When heated after thermo-mechanical programming, pronounced shape memory properties could be verified. The thermo-responsiveness of such multifunctional material systems may qualify them for usage in anti-counterfeiting applications.
KW - Poly(ester urethane)
KW - Shape memory polymer
KW - Thermo-responsiveness
KW - Information carrier
KW - QR code carrier
KW - Thermochromic properties
KW - Microencapsulated thermochromic pigments
KW - Anti-counterfeiting
KW - Smart label
KW - Difficult-to-copy
KW - Durability
KW - Multifuncitonal material systems
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-315176
DO - https://doi.org/10.1039/c4ra08977d
SN - 2046-2069
VL - 4
IS - 87
SP - 46680
EP - 46688
PB - RSC Publishing
CY - London
AN - OPUS4-31517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buckle, T.
A1 - van der Wal, S.
A1 - van Malderen, S.
A1 - Müller, Larissa
A1 - Kuil, J.
A1 - van Unen, V.
A1 - Peters, R.
A1 - van Bemmel, M.
A1 - McDonnell, L.
A1 - Velders, A.
A1 - Koning, F.
A1 - Vanhaeke, F.
A1 - van Leeuwen, F.
T1 - Hybrid imaging labels: providing the link between mass spectrometry-based molecular pathology and theranostics
N2 - Development of theranostic concepts that include inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation ICP-MS (LA-ICP-MS) imaging can be hindered by the lack of a direct comparison to more standardly used methods for in vitro and in vivo evaluation; e.g. fluorescence or nuclear medicine. In this study a bimodal (or rather, hybrid) tracer that contains both a fluorescent dye and a chelate was used to evaluate the existence of a direct link between mass spectrometry (MS) and in vitro and in vivo molecular imaging findings using fluorescence and radioisotopes. At the same time, the hybrid label was used to determine whether the use of a single isotope label would allow for MS-based diagnostics.
KW - Imaging
KW - Laser Ablation ICP-MS
KW - Diagnostics
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396813
DO - https://doi.org/10.7150/thno.17484
VL - 7
IS - 3
SP - 624
EP - 633
PB - IvySpring
AN - OPUS4-39681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Grothausmann, R.
A1 - Manke, I.
T1 - Verbesserte Elektronen-Tomographie mittels DIRECTT-Algorithmus
N2 - Tomographische Messungen in Transmissions-Elektronenmikroskopen beziehen ihren Reiz aus der hohen Ortsauflösung im Nanometerbereich. Allerdings bringen sie neben dem hohen Aufwand bei der Probenpräparation auch eine außerordentliche Häufung von Restriktionen der Messung mit sich, die bei Verwendung herkömmlicher Rekonstruktionsalgorithmen zu erheblichen Artefakten führen. Diese Restriktionen betreffen: partielle Nichtdurchstrahlbarkeit, einen eingeschränkten Winkelbereich, wenige Projektionen in Bezug auf die Detektorgröße, Probenabbildungen größer als der Detektor, instabile Rotationsachse, variierende Winkelinkremente sowie Probenveränderungen während der Messung.
Der DIRECTT-Algorithmus (Direkte iterative Rekonstruktion computertomographischer Trajektorien) kann, abgesehen von der Probenveränderung, sämtliche dieser Restriktionen geeignet berücksichtigen. Die auftretenden, teils unvollständigen Bahnen lassen sich mittels einer Treffertabelle und geeigneter Auswahl iterativ behandeln. Außerdem kann das Rekonstruktionsvolumen über die Detektorlänge hinaus erweitert werden.
Damit gelingt eine weitgehende Unterdrückung von Rekonstruktionsartefakten, insbesondere der sonst dominanten Streifenartefakte, und eine deutliche Erhöhung der Ortsauflösung. Die Verbesserung der Rekonstruktionsqualität wird anhand von Modell- und experimentellen Daten gezeigt.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Elektronen-Tomographie
KW - Computer-Tomographie
KW - Rekonstruktionsalgorithmen
PY - 2011
SN - 978-3-940283-33-7
IS - DGZfP-BB 127 (P8)
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-25004
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unnikrishnakurup, Sreedhar
A1 - Myrach, Philipp
A1 - Polomski, Benjamin
A1 - Le Claire, Elisabeth
A1 - Vengara, N.
A1 - Balasubramaniam, Krishnan
A1 - Ziegler, Mathias
T1 - Thermographic crack detection in hot steel surfaces
N2 - The detection and characterization of surface cracks in steel specimens prior to damage is a technologically and economically highly significant task and is of utmost importance when it comes to safety-relevant structures. In steel production where steel billets at high temperatures have to be inspected while moving a number of well-established NDT methods cannot be applied. Laser thermography however is a promising candidate to serve as a fast, non-contact and remote tool in this case. We present a study that shows that the crack detection capabilities of laser thermography can be extended also to specimens at high temperature. A combination of inductive and laser heating allows to systematically study the contrast formation as well as the optimization of the important measurement parameters. The experiments are accompanied by FEM simulations that provide a better insight of the physical correlations and support the experimental developments. The aim of these studies is to develop a system with high inspection speed and detection performance to be in-line operated under the hostile environment of steel production lines.
T2 - 19th World Conference on Non-Destructive Testing (WCNDT 2016)
CY - Munich, Germany
DA - 13.06.2016
KW - In-line Monitoring
KW - Laser Infrared thermography
KW - Cracks
KW - Induction heating
KW - Steel billets
KW - FEM simulation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389161
UR - http://ndt.net/?id=19573
SN - 1435-4934
VL - 21
IS - 7
SP - 1
EP - 8
PB - NDT.net
CY - Kirchwald
AN - OPUS4-38916
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuroiwa, T.
A1 - Zhu, Y.
A1 - Inagaki, K.
A1 - Long, S.
A1 - Christopher, S.
A1 - Puelles, M.
A1 - Porinsky, M.
A1 - Hatamleh, N.
A1 - Murby, J.
A1 - Merrick, J.
A1 - White, I.
A1 - Saxby, D.
A1 - Caciano de Sena, R.
A1 - Dominguez de Almeida, M.
A1 - Vogl, Jochen
A1 - Phukphatthanachai, Pranee
A1 - Fung, W.-H.
A1 - Yau, H.-P.
A1 - Okumu, T. O.
A1 - Kang'iri, J. N.
A1 - Tellez, J. A. S.
A1 - Campos, E. Z.
A1 - Galvan, E. C.
A1 - Kaewkhomdee, N.
A1 - Taebunpakul, S.
A1 - Thiengmanee, U.
A1 - Yafa, C.
A1 - Tokman, N.
A1 - Tunc, M.
A1 - Can, S. Z.
T1 - Report of the CCQM-K123: trace elements in biodiesel fuel
N2 - The CCQM-K123 key comparison was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to assess and document the capabilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of sodium, calcium, potassium, magnesium phosphorous and sulfur in biodiesel fuel (BDF). The National Metrology Institute of Japan (NMIJ) and National Institute of Standards and Technology (NIST) acted as the coordinating laboratories.
Results were submitted by 11 NMIs and DIs. The participants used different measurement methods, though most of them used inductively coupled plasma-mass spectrometry (ICP-MS), isotope dilution technique with ICP-MS and inductively coupled plasma-optical emission spectrometry (ICP-OES) with microwave acid digestion.
The material was quite challenging and a number of questions were raised at the IAWG meeting. Concerning S, the variation in S results between participants, particularly those using IDMS methods was discussed at the IAWG meeting. BAM, NIST and NMIJ reviewed their experimental conditions, results and/or uncertainty calculations for IDMS. According to the additional evaluation and investigation, the variances between the revised results became smaller than the original one, the revised results were overlapping between IDMS measurements of S content at the k=2 level. It is not possible to calculate a KCRV with values being modified after submission. It was concluded that this KC does not support S measurements.
Accounting for relative expanded uncertainty, comparability of measurement results for each of Na, Ca, K, Mg and P was successfully demonstrated by the participating NMIs or DIs. It is expected that sodium, calcium, potassium, magnesium and phosphorus at mass fractions greater than approximately 0.1 mg/kg, 0.1 mg/kg, 0.05 mg/kg, 0.05 mg/kg and 0.1 mg/kg respectively in biodiesel fuel and similar matrices (fuels and oils etc.) can be determined by each participant using the same technique(s) employed for this key comparison to achieve similar uncertainties mentioned in the present report. Furthermore, the results of this key comparison can be utilized along with the IAWG core capability approach.
KW - Biodiesel
KW - Fuel
KW - Sulphur
KW - Reference measurement
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393941
UR - http://iopscience.iop.org/article/10.1088/0026-1394/54/1A/08008/meta
DO - https://doi.org/10.1088/0026-1394/54/1A/08008
SN - 0026-1394
SN - 1681-7575
VL - 54
SP - Tech. Suppl. 2017, 08008, 1
EP - 47
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-39394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hsiao, I.-L.
A1 - Bierkandt, Frank
A1 - Reichardt, Ph.
A1 - Luch, A.
A1 - Huang, Y.-J.
A1 - Jakubowski, Norbert
A1 - Tentschert, J.
A1 - Haase, A.
T1 - Quantification and visualization of cellular uptake of TiO2 and Ag nanoparticles: comparison of different ICP-MS techniques
N2 - Safety assessment of nanoparticles (NPs) requires techniques that are suitable to quantify tissue and cellular uptake of NPs. The most commonly applied techniques for this purpose are based on inductively coupled plasma mass spectrometry (ICP-MS). Here we apply and compare three different ICP-MS methods to investigate the cellular uptake of TiO2 (diameter 7 or 20 nm, respectively) and Ag (diameter 50 or 75 nm, respectively) NPs into differentiated mouse neuroblastoma cells (Neuro-2a cells). Cells were incubated with different amounts of the NPs. Thereafter they were either directly analyzed by laser ablation ICP-MS (LA-ICP-MS) or were lysed and lysates were analyzed by ICP-MS and by single particle ICP-MS (SP-ICP-MS).
KW - Nanoparticles
KW - Single particle ICP-MS
KW - Laser ablation ICP-MS
KW - Cellular internalization
KW - Neurons
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-371620
DO - https://doi.org/10.1186/s12951-016-0203-z
SN - 1477-3155
VL - 14
SP - Article 50
AN - OPUS4-37162
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asadujjaman, Asad
A1 - Kent, B.
A1 - Bertin, Annabelle
T1 - Phase transition and aggregation behaviour of an UCST-type copolymer poly(acrylamide-coacrylonitrile) in water: effect of acrylonitrile content, concentration in solution, copolymer chain length and presence of electrolyte
N2 - An UCST-type copolymer of acrylamide (AAm) and acrylonitrile (AN) (poly(AAm-co-AN)) was prepared by reversible addition fragmentation chain transfer (RAFT) polymerization and its temperature-induced phase transition and aggregation behaviour studied by turbidimetry, static and dynamic light scattering, small angle neutron scattering (SANS) and cryo-transmission electron microscopy (cryo-TEM) measurements. The phase transition temperature was found to increase with increasing AN content in the copolymer, concentration of the solutions and copolymer chain length. A significant effect was observed onto the phase transition temperature by addition of different electrolytes into the copolymer solution. The copolymer chains were aggregated below the phase transition temperature and disaggregated above it. The size of the aggregates increases with increasing AN contents and concentration of the copolymer solutions below the phase transition temperature. The copolymer chains were expanded and weekly associated in solution above the phase transition temperature. A model is proposed to explain such association–aggregation behaviour of poly(AAm-co-AN) copolymers depending on AN contents and concentration of the copolymer solutions as a function of temperature.
KW - Thermoresponsive polymers
KW - UCST-type copolymer
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394636
DO - https://doi.org/10.1039/c6sm02262f
SN - 1744-683X
SN - 1744-6848
VL - 13
IS - 3
SP - 658
EP - 669
PB - RSC
AN - OPUS4-39463
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Babutzka, Martin
A1 - Heyn, A.
T1 - Dynamic tafel factor adaption for the evaluation of instantaneous corrosion rates on zinc by using gel-type electrolytes
N2 - The paper presents a new method for the determination and evaluation of tafel factors using gel-type electrolytes and electrochemical frequency modulation technique (EFM). This relatively new electrochemical method offers the possibility to determine both polarization resistances and tafel factors within one measurement and in short measuring intervals. Starting from a comprehensive parameter study it is shown that a direct relationship between the two values exists that can be described mathematically. This contribution presents the determined tafel factors for the system gel-type electrolyte/zinc and discusses their applicability and their limits.
T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
DA - 16.03.2017
KW - Gel-type electrolytes
KW - Gelartige Elektrolyte
KW - Zinc
KW - Zink
KW - Stern Geary constant
KW - Stern-Geary-Konstante
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394324
UR - http://iopscience.iop.org/article/10.1088/1757-899X/181/1/012021/pdf
DO - https://doi.org/10.1088/1757-899X/181/1/012021
SN - 1757-899X
SN - 1757-8981
VL - 181
IS - Conference 1
SP - Article UNSP 012021, 1
EP - 11
PB - IOP Publishing
CY - Bristol, UK
AN - OPUS4-39432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Krebber, Katerina
ED - Harun, S.W.
ED - Arof, H.
T1 - Smart technical textiles based on fiber optic sensors
N2 - Smart technical textiles are by definition textiles that can interact with their environment.
They can sense and react to environmental conditions and external stimuli from mechanical, thermal, chemical or other sources. Such textiles are multifunctional or even “intelligent” which is fulfilled by a number of sensors incorporated in the textiles. The embedded sensors are sensitive to various parameters such as temperature, strain, chemical, biological and other substances.
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-289397
SN - 978-953-51-1148-1
DO - https://doi.org/10.5772/54244
IS - Section 3 / Chapter 12
SP - 319
EP - 344
PB - InTech
AN - OPUS4-28939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Rabin, Ira
ED - Wandrey,
T1 - Building a bridge from the Dead Sea Scrolls
N2 - As part of the Qumran project conducted at the Federal Institute for Materials Research and Testing (BAM) in Berlin between 2007 and 2010, my colleagues and I developed a new, integrated methodology for determining the original and acquired properties of highly heterogeneous Dead Sea Scrolls. The purpose of this methodology is to help scholars determine the provenance of fragments of the scrolls and sort and compare them more easily than in the past. Since our measurements allowed us to differentiate between the minerals originating from the production processes and the sediments accrued during storage in the caves in Qumran, we were able to reconstruct the treatment of hides and discovered that at least two distinct parchmentproduction techniques co-existed at the beginning of the common era.
The reconstruction of workmanship on animal hides in Antiquity raised doubts about the validity of the current definition of parchment, which is based on a production technique known from the Middle Ages. We hope that our current work will also help researchers understand the characteristic properties of gewil, qelaf and dukhsustos better.¹
The evolution and socio-geographic distribution of writing inks in late Antiquity and the early Middle Ages are the second focus of our investigative work at BAM.
We use X-ray fluorescence analysis (XRF) to determine the chemical composition of inks and NIR reflectography for their typology. We are amply assisted in our ambitious enterprise by codicologists and palaeographers who have adopted our methodology and conduct field studies of their own.
KW - Dead Sea Scrolls
KW - Medieval Jewish manuscripts
KW - Material analysis
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435582
DO - https://doi.org/10.1515/9783110546422-0002
VL - 13
SP - 309
EP - 321
PB - de Gruyter
CY - Berlin
AN - OPUS4-43558
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Taffe, Alexander
A1 - Spies, M.
A1 - Recknagel, J.
T1 - Schulung zur zuverlässigen Ortung von Bewehrung in Stahlbetonbauteilen von Kraftwerken
N2 - In kerntechnischen Anlagen werden Revisionszeiträume genutzt, um unter anderem Anlagenteile nach dem Stand der Technik zu ertüchtigen und um Nachrüstungsmaßnahmen zur Erhöhung der Betriebssicherheit durchzuführen. Solche Anlagenteile werden häufig mittels Dübelplatten befestigt. Die Dübel sind in Stahlbetonbauteile einzubringen, die kraftwerkstypisch mit dichter Bewehrung versehen sind. Zerstörungsfreie Untersuchungen zur genauen Ortung bewehrungsfreier Orte sind hierzu erforderlich. Bei dieser vermeintlich einfachen Prüfaufgabe wurde deutlich, dass in der Praxis Bedarf an verbesserter Anwendungssicherheit der zur Verfügung stehenden ZFP-Verfahren besteht, die eng mit der Ausbildung von Prüfern verbunden ist. Dieser Beitrag berichtet über die bislang im Bereich ZfPBau erstmalig umgesetzte Strategie aus Verfahrensanweisung und Schulung zur zuverlässigen Ortung von Bewehrung an Stahlbetonbauteilen. Sie kann als Muster für weitere ZfPBau-Schulungen zur zuverlässigen Anwendung der Verfahren dienen.
T2 - Fachtagung Bauwerksdiagnose 2012 - Praktische Anwendungen zerstörungsfreier Prüfungen und Zukunftsaufgaben
CY - Berlin, Germany
DA - 23.02.2012
KW - Zerstörungsfreie Prüfung im Bauwesen
KW - ZfPBau
KW - Ausbildung
KW - Bewehrungsortung
KW - Bauwerksdiagnose
KW - Kernkraftwerk
KW - Bauwerksprüfung
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-285909
UR - https://bauwerksdiagnose2012.dgzfp.de/Portals/bwd2012/Dokumente/bb/v04.pdf
SN - 978-3-940283-40-5
IS - DGZfP BB 134
SP - 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-28590
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Taffe, Alexander
A1 - Spies, M.
A1 - Recknagel, J.
A1 - Rieß, H.
T1 - Schulung zur zuverlässigen Ortung von Bewehrung in Stahlbetonbauteilen von Kraftwerken
N2 - In kerntechnischen Anlagen werden Revisionszeiträume genutzt, um unter anderem Anlagenteile nach dem Stand der Technik zu ertüchtigen und um Nachrüstungsmaßnahmen zur Erhöhung der Betriebssicherheit durchzuführen. Solche Anlagenteile werden häufig mittels Dübelplatten befestigt. Die Dübel sind in Stahl-betonbauteile einzubringen, die kraftwerkstypisch mit dichter Bewehrung versehen sind. Zerstörungsfreie Untersuchungen zur genauen Ortung bewehrungsfreier Orte sind hierzu erforderlich. Bei dieser vermeintlich einfachen Prüfaufgabe wurde deutlich, dass in der Praxis Bedarf an verbesserter Anwendungssicherheit der zur Verfügung stehenden ZFP-Verfahren besteht, die eng mit der Ausbildung von Prüfern verbunden ist. Dieser Beitrag berichtet über die bislang im Bereich ZfPBau erstmalig umgesetzte Strategie aus Verfahrensanweisung und Schulung zur zuverlässigen Ortung von Bewehrung an Stahlbetonbauteilen. Sie kann als Muster für weitere ZfPBau-Schulungen zur zuverlässigen Anwendung der Verfahren dienen.
T2 - DGZfP-Jahrestagung 2011
CY - Bremen, Germany
DA - 30.05.2011
KW - Zerstörungsfreie Prüfung im Bauwesen
KW - Ausbildung
KW - Bewehrungsortung
KW - Performance demonstration
KW - Blindtest
KW - Wirbelstrom
KW - Radar
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-253752
UR - https://jt2011.dgzfp.de/Portals/jt2011/BB/di2b1.pdf
SN - 978-3-940283-33-7
IS - DGZfP BB 127
SP - 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-25375
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Illerhaus, Bernhard
A1 - Onel, Yener
T1 - Mehr Strom oder mehr Spannung, ein Vergleich drei Röntgenröhren in der CT
N2 - Sollten CT Aufnahmen quantitativ und automatisch ausgewertet werden, ist die Qualität der Tomogramme ein wesentlicher Punkt. Außerdem steht bei Serienmessungen nur eine begrenzte Meßzeit für jede Probe. Es werden die verschiedenen Mikrofokusröhren in Bezug auf die Parameter Orts- und Dichteauflösung, sowie Meßzeit verglichen, CT Beispiele dazu gezeigt.
T2 - DGZfP-Jahrestagung 2014
CY - Potsdam, Germany
DA - 26.05.2014
KW - Computertomographie
KW - Ortsauflösung
KW - Röhrenvergleich
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-307629
SN - 978-3-940283-61-0
IS - DGZfP-BB 148
SP - Di.1A.1, 1
EP - 9
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
AN - OPUS4-30762
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lück, S.
A1 - Kupsch, Andreas
A1 - Lange, Axel
A1 - Hentschel, Manfred P.
A1 - Schmidt, V.
T1 - Statistical analysis of tomographic reconstruction algorithms by morphological image characteristics
N2 - We suggest a procedure for quantitative quality control of tomographic reconstruction algorithms. Our task-oriented evaluation focuses on the correct reproduction of phase boundary length and has thus a clear implication for morphological image analysis of tomographic data. Indirectly the method monitors accurate reproduction of a variety of locally defined critical image features within tomograms such as interface positions and microstructures, debonding, cracks and pores. Tomographic errors of such local nature are neglected if only global integral characteristics such as mean squared deviation are considered for the evaluation of an algorithm. The significance of differences in reconstruction quality between algorithms is assessed using a sample of independent random scenes to be reconstructed. These are generated by a Boolean model and thus exhibit a substantial stochastic variability with respect to image morphology. It is demonstrated that phase boundaries in standard reconstructions by filtered backprojection exhibit substantial errors. In the setting of our simulations, these could be significantly reduced by the use of the innovative reconstruction algorithm DIRECTT.
KW - Tomography
KW - Computed tomography
KW - Reconstruction algorithm
KW - Morphological image analysis
KW - Phase boundary
KW - Metrology
KW - Non-destructive testing
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-210710
DO - https://doi.org/10.5566/ias.v29.p61-77
SN - 1580-3139
SN - 1854-5165
VL - 29
SP - 61
EP - 77
CY - Ljubljana, Slovenia
AN - OPUS4-21071
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drogan, D.
A1 - Sheldrick, A. J.
A1 - Schütze, M.
A1 - Knüppel, S.
A1 - Andersohn, F.
A1 - di Giuseppe, R.
A1 - Herrmann, Bianca
A1 - Willich, S. N.
A1 - Garbe, E.
A1 - Bergmann, M. M.
A1 - Boeing, H.
A1 - Weikert, C.
T1 - Alcohol consumption, genetic variants in alcohol deydrogenases, and risk of cardiovascular diseases: A prospective study and meta-analysis
N2 - Objective: First, to investigate and compare associations between alcohol consumption and variants in alcohol dehydrogenase (ADH) genes with incidence of cardiovascular diseases (CVD) in a large German cohort. Second, to quantitatively summarize available evidence of prospective studies on polymorphisms in ADH1B and ADH1C and CVD-risk.
Methods: We conducted a case-cohort study nested within the European Prospective Investigation into Cancer and Nutrition (EPIC)-Potsdam cohort including a randomly drawn subcohort (n = 2175) and incident cases of myocardial infarction (MI; n = 230) or stroke (n = 208). Mean follow-up time was 8.2±2.2 years. The association between alcohol consumption, ADH1B or ADH1C genotypes, and CVD-risk was assessed using Cox proportional hazards regression. Additionally, we report results on associations of variants in ADH1B and ADH1C with ischemic heart disease and stroke in the context of a meta-analysis of previously published prospective studies published up to November 2011.
Results: Compared to individuals who drank >0 to 6 g alcohol/d, we observed a reduced risk of MI among females consuming >12 g alcohol/d (HR = 0.31; 95% CI: 0.10–0.97) and among males consuming >24 to 60 g/d (HR = 0.57; 95% CI: 0.33–0.98) or >60 g alcohol/d (HR = 0.30; 95% CI: 0.12–0.78). Stroke risk was not significantly related to alcohol consumption >6 g/d, but we observed an increased risk of stroke in men reporting no alcohol consumption. Individuals with the slowcoding ADH1B*1/1 genotype reported higher median alcohol consumption. Yet, polymorphisms in ADH1B or ADH1C were not significantly associated with risk of CVD in our data and after pooling results of eligible prospective studies [ADH1B*1/1: RR = 1.35 (95% CI: 0.98–1.88; p for heterogeneity: 0.364); ADH1C*2/2: RR = 1.07 (95% CI: 0.90–1.27; p for heterogeneity: 0.098)].
Conclusion: The well described association between alcohol consumption and CVD-risk is not reflected by ADH polymorphisms, which modify the rate of ethanol oxidation.
KW - Coronary heart disease
KW - Myocardial infarction
KW - Dehydrogenase
KW - Genotypes
KW - Relative validity
KW - Drinking habits
KW - EPIC-Potsdam Study
KW - German part
KW - Case cohort
KW - Stroke
KW - Reproducibility
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633710
DO - https://doi.org/10.1371/journal.pone.0032176
SN - 1932-6203
N1 - The recruitment phase of the EPIC-Potsdam Study was supported by the Federal Ministry of Science, Germany (01 EA 9401), and the European Union (SOC 95201408 05F02). The follow-up was supported by the German Cancer Aid (70-2488-Ha I) and the European Community (SOC 98200769 05F02).
VL - 7
IS - 2
SP - 1
EP - 11
PB - Public Library of Science (PLoS)
CY - San Francisco, California, US
AN - OPUS4-63371
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Werner
A1 - Saathoff, F.
T1 - Geosynthetics in geoenvironmental engineering
N2 - Geosynthetics are planar polymeric products, which are used in connection with soil, rock or other soil-like materials to fulfill various functions in geoenvironmental engineering. Geosynthetics are of ever-growing importance in the construction industry. Sealing of waste storage facilities to safely prevent the emission of wastewater, landfill gas and contaminated dust as well as the diffusion of pollutants into the environment and coastal protection against storms and floods and reconstruction after natural disaster are important fields of application. We will give an overview of the various geosynthetic products. Two examples of the material problems related to geosynthetics are discussed in detail: the effect of creep on the long-term performance of geocomposite drains and the numerical simulation of the interaction of soil with geogrids. Both issues are of importance for the use of these products in landfill capping systems. The various functions, which geosynthetics may fulfill in the protection of coastal lines, are illustrated by case studies. The geosynthetic market is evaluated and economical and environmental benefits, as well as environmental side effects related to the use of geosynthetics, are discussed.
KW - Geosynthetics
KW - Geoenvironmental engineering
KW - Landfill capping system
KW - Coastal protection
KW - Geocomposite drain
KW - Geogrid
KW - Geotextile
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-332014
DO - https://doi.org/10.1088/1468-6996/16/3/034605
SN - 1468-6996
VL - 16
IS - 3
SP - 034605-1
EP - 034605-20
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-33201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilhelm, Stefan
A1 - Kaiser, Martin
A1 - Würth, Christian
A1 - Heiland, J.
A1 - Carrillo-Carrion, C.
A1 - Muhr, V.
A1 - Wolfbeis, Otto S.
A1 - Parak, W.J.
A1 - Resch-Genger, Ute
A1 - Hirsch, T.
T1 - Water dispersible upconverting nanoparticles: effects of surface modification on their luminescence and colloidal stability
N2 - We present a systematic study on the effect of surface ligands on the luminescence properties and colloidal stability of β-NaYF4:Yb3+,Er3+ upconversion nanoparticles (UCNPs), comparing nine different surface coatings to render these UCNPs water-dispersible and bioconjugatable. A prerequisite for this study was a large-scale synthetic method that yields ~2 g per batch of monodisperse oleate-capped UCNPs providing identical core particles. These ~23 nm sized UCNPs display an upconversion quantum yield of ~0.35% when dispersed in cyclohexane and excited with a power density of 150 W cm-2, underlining their high quality. A comparison of the colloidal stability and luminescence properties of these UCNPs, subsequently surface modified with ligand exchange or encapsulation protocols, revealed that the ratio of the green (545 nm) and red (658 nm) emission bands determined at a constant excitation power density clearly depends on the surface chemistry. Modifications relying on the deposition of additional (amphiphilic) layer coatings, where the initial oleate coating is retained, show reduced non-radiative quenching by water as compared to UCNPs that are rendered water-dispersible via ligand exchange. Moreover, we could demonstrate that the brightness of the upconversion luminescence of the UCNPs is strongly affected by the type of surface modification, i.e., ligand exchange or encapsulation, yet hardly by the chemical nature of the ligand.
KW - upconverting nanoparticles (UCNPs)
KW - Luminescence
KW - surface modification
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324071
DO - https://doi.org/10.1039/c4nr05954a
SN - 2040-3364
SN - 2040-3372
VL - 7
IS - 4
SP - 1403
EP - 1410
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-32407
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heyn, A.
A1 - Müller, Thoralf
A1 - Balzer, M.
A1 - Fenker, M.
A1 - Kappl, H.
T1 - Corrosion protection mechanisms of TiMgN hard coatings on steel
N2 - Hard coated steel components are used in a wide application range, mostly for protective, wear resistant and decorative purposes. Despite of these coatings being regarded as relatively dense, there is always a high risk of localized corrosion when a coated low alloyed steel component encounters a surrounding high humidity atmosphere or even an aqueous medium. An approach to enhance the corrosion properties is the addition of magnesium to physical vapor deposited hard coatings, like TiN. It has been found that there is a remarkable increase in corrosion resistance in dependence of magnesium content of the TiMgN coating and its surface properties. In this work the authors will explain the underlying corrosion protection mechanisms by means of electrochemical and analytical studies. The positive impact of magnesium in the coating relates on its preferred dissolution vs. steel. This causes the potential to shift to more negative direction with respect to the steel substrate and additionally leads to a temporarily passivation of the steel due to alkalization of the surrounding electrolyte by formation of magnesium hydroxide.
T2 - 20. Werkstofftechnisches Kolloquium
CY - Chemnitz, Germany
DA - 14.03.2018
KW - Corrosion
KW - Titanium nitride
KW - PVD hard coating
KW - magnesium
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457117
DO - https://doi.org/10.1088/1757-899X/373/1/012009
SN - 1757-8981
VL - 373
IS - 1
SP - 012009, 1
EP - 10
PB - IOP Publishing Ltd
AN - OPUS4-45711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiegner, Katharina
A1 - Hahn, Oliver
A1 - Horn, Wolfgang
A1 - Farke, M.
A1 - Kalus, Sabine
A1 - Nohr, Michael
A1 - Jann, Oliver
T1 - Determination of formic and acetic acid emissions in indoor air or from building products
N2 - Several construction and building materials, including wood, glue and coatings, are possible sources of very volatile organic compounds (VVOCs) and volatile organic compounds (VOCs) like formic and acetic acid. Due to very high air tightness and very low air exchange rates in new buildings concentrations of these harmful substances can increase considerably. To minimize the risk, emissions from building products should be identified and quantified. With the common standard method, this means Tenax® sampling followed by thermal desorption and GC-MS analysis, these acids could not be detected sufficiently. The aim oft this study is the comparison of two different methods for the determination of acetic and formic acid. The sampling of method one, which is usually used for identification and quantification of VOCs, is done in accordance with ISO 16000-6 and ISO 16017-1 on Carbotrap® 202 multi-bed thermal desorption tube by subsequent identification and quantification with GC-MS. Method two is based on sampling on 2,4-dinitrophenylhydrazine (DNPH) cartridges, derivatisation, elution, identification and quantification of the derivatives with LC-MS/MS (liquid chromatography mass spectrometry/mass spectrometry).
N2 - Viele Konstruktions- und Baumaterialien, wie Holz, Kleber und Anstriche, sind mögliche Quellen für leicht flüchtige organische Verbindungen (VVOC) und flüchtige organische Verbindungen (VOC), wie Ameisen- und Essigsäure. Bedingt durch die hohe Dichtigkeit und den damit verbundenen niedrigen Luftwechsel in neuen Gebäuden können die Konzentrationen dieser gesundheitsgefährdenden Substanzen beträchtlich ansteigen. Um das Risiko zu minimieren, sollen Emissionen aus Bauprodukten identifiziert und quantifiziert werden. Mit der üblichen Standardmethode, die auf einer Luftprobenahme auf Tenax® und anschließender Analyse mittels GC-MS basiert, können diese Säuren nicht ausreichend detektiert werden. Ziel dieser Arbeit ist der Vergleich von zwei unterschiedlichen Methoden zur Bestimmung von Essig- und Ameisensäure. Die Luftprobenahme der ersten Methode, die üblicherweise zur Identifizierung und Quantifizierung von VOC genutzt wird, wurde gemäß ISO 16000-6 and ISO 16017-1 auf Carbotrap® 202, ein mit mehreren Adsorbentien gepacktes Thermodesorptionsrohr, mit anschließender Identifikation und Quantifizierung mittels GC-MS durchgeführt. Die zweite Methode basiert auf einer Luftprobenahme mittels 2,4-Dinitrophenylhydrazin-(DNPH)-Kartuschen, Derivatisierung, Elution, Identifikation und Quantifizierung der Derivate mit LC-MS/MS (Flüssigkeitschromatographie Massenspektometrie/Massenspektometrie).
KW - Formic acid
KW - Acetic acid
KW - VVOCs
KW - Air sampling
KW - DNPH
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-255911
UR - http://www.gefahrstoffe.de/gest/article.php?data[article_id]=65887
SN - 0949-8036
SN - 0039-0771
SN - 1436-4891
VL - 72
IS - 3
SP - 84
EP - 88
PB - Springer-VDI-Verlag
CY - Düsseldorf
AN - OPUS4-25591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Moschner, J.
A1 - Mikolajczak, D. J.
A1 - Becker, M.
A1 - Thünemann, Andreas
A1 - Kästner, Claudia
A1 - Klemczak, D.
A1 - Stegemann, A.-K.
A1 - Böttcher, C.
A1 - Metrangolo, P.
A1 - Netz, R. R.
A1 - Koksch, B.
T1 - The Impact of Halogenated Phenylalanine Derivatives on NFGAIL Amyloid Formation
N2 - The hexapeptide hIAPP22–27 (NFGAIL) is known as a crucial amyloid core sequence of the human islet amyloid polypeptide (hIAPP) whose aggregates can be used to better understand the wild‐type hIAPP′s toxicity to β‐cell death. In amyloid research, the role of hydrophobic and aromatic‐aromatic interactions as potential driving forces during the aggregation process is controversially discussed not only in case of NFGAIL, but also for amyloidogenic peptides in general. We have used halogenation of the aromatic residue as a strategy to modulate hydrophobic and aromatic‐aromatic interactions and prepared a library of NFGAIL variants containing fluorinated and iodinated phenylalanine analogues. We used thioflavin T staining, transmission electron microscopy (TEM) and small‐angle X‐ray scattering (SAXS) to study the impact of side‐chain halogenation on NFGAIL amyloid formation kinetics. Our data revealed a synergy between aggregation behavior and hydrophobicity of the phenylalanine residue. This study introduces systematic fluorination as a toolbox to further investigate the nature of the amyloid self‐assembly process.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Nanostructure
KW - Peptide
KW - Amyloid
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518632
DO - https://doi.org/10.1002/cbic.202000373
VL - 21
IS - 24
SP - 3544
EP - 3554
PB - Wiley
CY - Weinheim
AN - OPUS4-51863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brandl, F.
A1 - Thünemann, Andreas
A1 - Beuermann, S.
T1 - Poly(meth)acrylate-PVDF core–shell particles from emulsion polymerization: preferential formation of the PVDF β crystal phase
N2 - A facile and convenient approach for the synthesis of core–shell particles via emulsion polymerization is presented. The shell consists of poly(vinylidene fluoride) (PVDF) and the core of poly(methyl methacrylate) (PMMA), poly(glycidyl methacrylate) (PGMA) or poly(methyl acrylate) (PMA). In a first step, a non-fluorinated (meth)acrylate monomer is polymerized in the emulsion to produce poly(meth)acrylate core particles. Secondly, vinylidene fluoride (VDF) is directly added to the reactor and polymerized for shell formation. Small-angle X-ray scattering (SAXS) was employed to characterize the structure of the core–shell particles. Interestingly, the particles’ core contains fluorinated and non-fluorinated polymers, whereas the shell of the particles consists only of PVDF. The resulting particles with a diameter of around 40 nm show a significantly higher PVDF β phase content than the PVDF homopolymer obtained by emulsion polymerization
KW - Small-angle x-ray scattering
KW - SAXS
KW - Nanopatricle
KW - Polymer
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465910
DO - https://doi.org/10.1039/C8PY01236A
SN - 1759-9954
SN - 1759-9962
VL - 9
IS - 44
SP - 5359
EP - 5369
PB - The Royal Society of Chemistry
AN - OPUS4-46591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liebig, F.
A1 - Sarhan, R. M.
A1 - Schmitt, C. N. Z.
A1 - Thünemann, Andreas
A1 - Prietzel, C.
A1 - Bargheer, M.
A1 - Koetz, J.
T1 - Gold Nanotriangles with Crumble Topping and their Influence on Catalysis and Surface‐Enhanced Raman Spectroscopy
N2 - By adding hyaluronic acid (HA) to dioctyl sodium sulfosuccinate (AOT)‐stabilized gold nanotriangles (AuNTs) with an average thickness of 7.5±1 nm and an edge length of about 175±17 nm, the AOT bilayer is replaced by a polymeric HA‐layer leading to biocompatible nanoplatelets. The subsequent reduction process of tetrachloroauric acid in the HA‐shell surrounding the AuNTs leads to the formation of spherical gold nanoparticles on the platelet surface. With increasing tetrachloroauric acid concentration, the decoration with gold nanoparticles can be tuned. SAXS measurements reveal an increase of the platelet thickness up to around 14.5 nm, twice the initial value of bare AuNTs. HRTEM micrographs show welding phenomena between densely packed particles on the platelet surface, leading to a crumble formation while preserving the original crystal structure. Crumbles crystallized on top of the platelets enhance the Raman signal by a factor of around 20, and intensify the plasmon‐driven dimerization of 4‐nitrothiophenol (4‐NTP) to 4,4′‐dimercaptoazobenzene in a yield of up to 50 %. The resulting crumbled nanotriangles, with a biopolymer shell and the absorption maximum in the second window for in vivo imaging, are promising candidates for biomedical sensing.
KW - SAXS
KW - Small-angle X-ray scattering
KW - Nanoparticle
KW - Gold
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503977
DO - https://doi.org/10.1002/cplu.201900745
VL - 85
IS - 3
SP - 519
EP - 526
PB - Wiley-VCH Verlag
CY - Weinheim
AN - OPUS4-50397
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästner, Claudia
A1 - Böhmert, Linda
A1 - Braeuning, Albert
A1 - Lampen, Alfonso
A1 - Thünemann, Andreas
T1 - Fate of fluorescence labels - Their adsorption and desorption kinetics to silver nanoparticles
N2 - Silver nanoparticles are among the most widely used and produced nanoparticles. Because of their frequent application in consumer products, the assessment of their toxicological potential has seen a renewed importance. A Major difficulty is the traceability of nanoparticles in in vitro and in vivo experiments. Even if the particles are labeled, for example, by a fluorescent marker, the dynamic exchange of ligands often prohibits their spatial localization. Our study provides an insight into the adsorption and desorption kinetics of two different fluorescent labels on silver nanoparticles with a core radius of 3 nm by dynamic light scattering, small-angle X-ray scattering, and fluorescence spectroscopy. We used BSA-FITC and tyrosine as examples for common fluorescent ligands. It is shown that the adsorption of BSA-FITC takes at least 3 days, whereas tyrosine adsorbs immediately. The quantitative amount of stabilizer on the particle surface was determined by fluorescence spectroscopy and revealed that the particles are stabilized by a monolayer of BSA-FITC (corresponding to 20 ± 9 molecules), whereas tyrosine forms a multilayered structure consisting of 15900 ± 200 molecules. Desorption experiments show that the BSA-FITC-stabilized particles are ideally suited for application in in vitro and in vivo experiments because the ligand desorption takes several days. Depending on the BSA concentration in the particles surroundings, the rate constant is k = 0.2 per day or lower when applying first order kinetics, that is, 50% of the BSAFITC molecules are released from the particle’s surface within 3.4 days. For illustration, we provide a first application of the fluorescence-labeled particles in an uptake study with two different commonly used cell lines, the human liver cell model HepG2 and the human intestinal cell model of differentiated Caco-2 cells.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Silver nanoparticles
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452166
DO - https://doi.org/10.1021/acs.langmuir.8b01305
SN - 1520-5827
SN - 0743-7463
VL - 34
IS - 24
SP - 7153
EP - 7160
PB - American Chemical Society
AN - OPUS4-45216
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Smales, Glen Jacob
A1 - Clark, Adam H.
A1 - Thünemann, Andreas
T1 - Zinc Phosphate Nanoparticles Produced in Saliva
N2 - This paper reports the formation of zinc phosphate nanoparticles from the artificial digestion of zinc chloride. Initially, the formation of amorphous primary particles with a mean radius of 1.1 nm is observed, alongside the formation of larger, protein stabilized aggregates. These aggregates, with a radius of gyration of 37 nm, are observed after 5 minutes of exposure to artificial saliva and are shown to be colloidally stable for a minimum time of two weeks. The initially formed primary particles are thought to consist of amorphous zinc phosphate, which is then transformed into crystalline Zn3(PO4)2·4H2O over the course of two weeks. Our results demonstrate that the interaction of inorganic salts with bodily fluids can induce the formation of de novo nanoparticles, which in turn, provides insights into how zinc‐enriched foods may also facilitate the formation of nanoparticles upon contact with saliva. As such, this may be considered as an undesirable (bio)mineralization.
KW - SAXS
KW - Digestion
KW - Zinc phosphate
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514239
DO - https://doi.org/10.1002/ejic.202000521
IS - 38
SP - 3654
EP - 3661
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-51423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Kästner, Claudia
A1 - Thünemann, Andreas
T1 - High-speed but not magic: Microwave-assisted synthesis of ultra-small silver nanoparticles
N2 - Reaction procedures have been improved to achieve higher yields and shorter reaction times: one possibility is the usage of microwave reactors. In the literature, this is under discussion, for example, nonthermal effects resulting from the microwave radiation are claimed. Especially for the synthesis of nanomaterials, it is of crucial importance to be aware of influences on the reaction pathway. Therefore, we compare the syntheses of ultra-small silver nanoparticles via conventional and microwave heating. We employed a versatile one-pot polyol synthesis of poly(acrylic acid)-stabilized silver nanoparticles, which display superior catalytic properties. No microwave-specific effects in terms of particle size distribution characteristics, as derived by small-angle X-ray scattering and dynamic light scattering, are revealed. Because of the characteristics of a closed system, microwave reactors give access to elevated temperatures and pressures. Therefore, the speed of particle formation can be increased by a factor of 30 when the reaction temperature is increased from 200 to 250 °C. The particle growth process follows a cluster coalescence mechanism. A postsynthetic incubation step at 250 °C induces a further growth of the particles while the size distribution broadens. Thus, utilization of microwave reactors enables an enormous decrease of the reaction time as well as the opportunity of tuning the particle size. Possibly, decomposition of the stabilizing ligand at elevated temperatures results in reduced yields. A compromise between short reaction times and high yields can be found at a temperature of 250 °C and a corresponding reaction time of 30 s.
KW - Silver nanoparticles
KW - SAXS
KW - Small-angle X-ray scattering
KW - Microwave synthesis
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-437028
DO - https://doi.org/10.1021/acs.langmuir.7b01541
SN - 0743-7463
SN - 1520-5827
VL - 34
IS - 1
SP - 147
EP - 153
PB - American Chemical Society
CY - Washington, D.C.
AN - OPUS4-43702
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kästner, Claudia
A1 - Saloga, Patrick E. J.
A1 - Thünemann, Andreas
T1 - Kinetic monitoring of glutathione-induced silver nanoparticle disintegration
N2 - We report on etching of polyacrylic acid-stabilised silver nanoparticles in the presence of glutathione (GSH). The initial particles with a radius of 3.2 nm and consisting of ∼8100 silver atoms dissolve in a two-step reaction mechanism while in parallel smaller silver particles with a radius of 0.65 nm and consisting of 60 to 70 silver atoms were formed. The kinetics of the etching of the initial particles, accompanied by formation of smaller silver particles was interpreted based on in situ, time-resolved small-angle X-ray scattering (SAXS) experiments.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Silver nanoparticles
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-452464
DO - https://doi.org/10.1039/c8nr02369g
SN - 2040-3372
VL - 10
IS - 24
SP - 11485
EP - 11490
PB - The Royal Society of Chemistry
AN - OPUS4-45246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chowdhary, S.
A1 - Schmidt, R. F.
A1 - Sahoo, A. K.
A1 - tom Dieck, T.
A1 - Hohmann, T.
A1 - Schade, B.
A1 - Brademann-Jock, Kerstin
A1 - Thünemann, Andreas
A1 - Netz, R. R.
A1 - Gradzielski, M.
A1 - Koksch, B.
T1 - Rational design of amphiphilic fluorinated peptides: Evaluation of self-assembly properties and hydrogel formation
N2 - Advanced peptide-based nanomaterials composed of self-assembling peptides (SAPs) are of emerging interest in pharmaceutical and biomedical applications. The introduction of fluorine into peptides, in fact, offers unique opportunities to tune their biophysical properties and intermolecular interactions. In particular, the degree of fluorination plays a crucial role in peptide engineering as it can be used to control the characteristics of fluorine-specific interactions and, thus, peptide conformation and self-assembly. Here, we designed and explored a series of amphipathic peptides by incorporating the fluorinated amino acids (2S)-4-monofluoroethylglycine (MfeGly), (2S)-4,4-difluoroethylglycine (DfeGly) and (2S)-4,4,4-trifluoroethylglycine (TfeGly) as hydrophobic components. This approach enabled studying the impact of fluorination on secondary structure formation and peptide self-assembly on a systematic basis. We show that the interplay between polarity and hydrophobicity, both induced differentially by varying degrees of side chain fluorination, does affect peptide folding significantly. A greater degree of fluorination promotes peptide fibrillation and subsequent formation of physical hydrogels in physiological conditions. Molecular simulations revealed the key role played by electrostatically driven intra-chain and inter-chain contact pairs that are modulated by side chain fluorination and give insights into the different self-organization behaviour of selected peptides. Our study provides a systematic report about the distinct features of fluorinated oligomeric peptides with potential applications as peptide-based biomaterials.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Amyloid
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553504
DO - https://doi.org/10.1039/D2NR01648F
SN - 2040-3364
VL - 14
IS - 28
SP - 10176
EP - 10189
PB - Royal Society of Chemistry
AN - OPUS4-55350
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Yokosawa, T.
A1 - Spiecker, E.
A1 - Klinger, D.
T1 - Regioselective Seeded Polymerization in Block Copolymer Nanoparticles: Post-Assembly Control of Colloidal Features
N2 - Post-assembly modifications are efficient tools to adjust colloidal features of block copolymer (BCP) particles. However, existing methods often address particle shape, morphology, and chemical functionality individually. For simultaneous control, we transferred the concept of seeded polymerization to phase separated BCP particles. Key to our approach is the regioselective polymerization of (functional) monomers inside specific BCP domains. This was demonstrated in striped PS-b-P2VP ellipsoids. Here, polymerization of styrene preferably occurs in PS domains and increases PS lamellar thickness up to 5-fold. The resulting asymmetric lamellar morphology also changes the particle shape, i.e., increases the aspect ratio. Using 4-vinylbenzyl azide as co-monomer, azides as chemical functionalities can be added selectively to the PS domains. Overall, our simple and versatile method gives access to various multifunctional BCP colloids from a single batch of pre-formed particles.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanostructure
KW - Polymer
KW - Nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557246
DO - https://doi.org/10.1002/anie.202208084
SN - 1433-7851
VL - 61
IS - 35
SP - 1
EP - 11
PB - Wiley
CY - Weinheim
AN - OPUS4-55724
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, M. B.
A1 - Fahrenson, C.
A1 - Givelet, L.
A1 - Herrmann, T.
A1 - Loescher, K.
A1 - Böhmert, L.
A1 - Thünemann, Andreas
A1 - Braeuning, A.
A1 - Sieg, H.
T1 - Beyond microplastics ‑ investigation on health impacts of submicron and nanoplastic particles after oral uptake in vitro
N2 - The continuously increasing use of plastics is supposed to result in a rising exposure of MNPs to humans. Available data on human health risks of microplastics after oral uptake increased immensely in the past years and indicates very likely only low risks after oral consumption. Concerning nanoplastics, uptake, transport and potential adverse effects after oral uptake are less well understood. This study aims to investigate differences between microplastic particles and particles in the submicron- and nanoscaled size derived from food-relevant polymers with a particle size range consistent with higher potential for cellular uptake, fate, and effects when applied to human intestinal and liver cells. This work includes the development of cellular and subcellular detection methods for synthetic polymeric particles in the micro- and nanometer-range, using Scanning Electron Microscopy, Small-Angle X-ray and Dynamic Light Scattering methods, Asymmetric Flow Field Flow Fractionation, octanol-water fractionation, fluorescence microscopy and flow cytometry. Polylactic acid (250 nm and 2 μm (polydisperse)), melamine formaldehyde (366 nm) and polymethylmethacrylate (25 nm) were thoroughly characterized. The submicro- and nanoplastic test particles showed an increased uptake and transport quantity through intestinal cells. Both types of particles resulted in observed differences of uptake behavior, most likely influenced by different lipophilicity, which varied between the polymeric test materials. Toxic effects were detected after 24 h only in overload situations for the particles in the submicrometer range. This study provides further evidence for gastrointestinal uptake of submicro- and nanoplastics and points towards differences regarding bioavailability between microplastics and smaller plastic particles that may result following the ingestion of contaminated food and beverages. Furthermore, the results reinforce the importance for studying nanoplastics of different materials of varying size, surface properties, polymer composition and hydrophobicity.
KW - Small-angle X-ray scattering
KW - SAXS
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550741
DO - https://doi.org/10.1186/s43591-022-00036-0
VL - 2
SP - 1
EP - 19
PB - Springer Nature
AN - OPUS4-55074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Navarro, L.
A1 - Thünemann, Andreas
A1 - Klinger, D.
T1 - Solvent Annealing of Striped Ellipsoidal Block Copolymer Particles: Reversible Control over Lamellae Asymmetry, Aspect Ratio, and Particle Surface
N2 - Solvent annealing is a versatile tool to adjust the shape and morphology of block copolymer (BCP) particles. During this process, polar solvents are often used for block-selective swelling. However, such water-miscible solvents can induce (partial) solubilization of one block in the surrounding aqueous medium, thus, causing complex structural variations and even particle disassembly. To reduce the complexity in morphology control, we focused on toluene as a nonpolar polystyrene-selective solvent for the annealing of striped polystyrene-b-poly(2-vinylpyridine) (PS-b-P2VP) ellipsoids. The selective stretching of PS chains produces unique asymmetric lamellae structures, which translate to an increase in the particle aspect ratio after toluene evaporation. Complete reversibility is achieved by changing to chloroform as a nonselective solvent. Moreover, surfactants can be used to tune block-selective wetting of the particle surface during the annealing; for example, a PS shell can protect the internal lamellae structure from disassembly. Overall, this versatile postassembly process enables the tailoring of the structural features of striped colloidal ellipsoids by only using commercial BCPs and solvents.
KW - Small-angle X-ray scattering
KW - SAXS
KW - Nanoparticle
KW - Polymer
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543731
DO - https://doi.org/10.1021/acsmacrolett.1c00665
VL - 11
IS - 3
SP - 319
EP - 335
PB - American Chemical Society
AN - OPUS4-54373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Voss, L.
A1 - Hoche, E.
A1 - Stock, V.
A1 - Böhmert, L.
A1 - Braeuning, A.
A1 - Thünemann, Andreas
A1 - Sieg, H.
T1 - Intestinal and hepatic effects of iron oxide nanoparticles
N2 - Iron oxide nanoparticles gain increasing attention due to their broad industrial use. However, safety concerns exist since their effects on human cells are still under investigation. The presence of iron oxide nanoparticles in the food pigment E172 has been shown recently. Here, we studied four iron oxide nanoparticles, one food pigment E172 and the ionic control FeSO4 regarding dissolution in biological media, uptake and transport, and cellular effects in vitro in human intestinal Caco-2 and HepaRG hepatocarcinoma cells. The iron oxide nanoparticles passed the gastrointestinal passage without dissolution and reached the intestine in the form of particles. Minor uptake was seen into Caco-2 cells but almost no transport to the basolateral site was detected for any of the tested particles. HepaRG cells showed higher particle uptake. Caco-2 cells showed no alterations in reactive oxygen species production, apoptosis, or mitochondrial membrane potential, whereas two particles induced apoptosis in HepaRG cells, and one altered mitochondrial membrane potential at non-cytotoxic concentrations. No correlation between physicochemical particle characteristics and cellular effects was observed, thus emphasizing the Need for case-by-case assessment of iron oxide nanoparticles.
KW - Nanoparticles
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521651
DO - https://doi.org/10.1007/s00204-020-02960-7
VL - 95
IS - 3
SP - 895
EP - 905
PB - Springer
AN - OPUS4-52165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smith, A. J.
A1 - Snow, T.
A1 - Shebanova, O.
A1 - Sutter, J. P.
A1 - Ilavsky, J.
A1 - Hermida-Merino, D.
A1 - Smales, Glen Jacob
A1 - Terrill, N. J.
A1 - Thünemann, Andreas
A1 - Bras, W.
T1 - Extending synchrotron SAXS instrument ranges through addition of a portable, inexpensive USAXS module with vertical rotation axes
N2 - Ultra-SAXS can enhance the capabilities of existing synchrotron SAXS/WAXS beamlines. A compact ultra-SAXS module has been developed, which extends the measurable q-range with 0.0015 ≤ q (nm−1) ≤ 0.2, allowing structural dimensions in the range 30 ≤ D (nm) ≤ 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements. The use of vertical crystal rotation axes (horizontal diffraction) greatly simplifies the construction, at minimal cost to efficiency. In this paper, the design considerations, realization and synchrotron findings are presented. Measurements of silica spheres, an alumina membrane, and a porous carbon catalyst are provided as application examples.
KW - X-ray scattering
KW - Microstructure
KW - Instrumentation
KW - SAXS
KW - USAXS
KW - Nanostructure
KW - Combined techniques
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524919
DO - https://doi.org/10.1107/S1600577521003313
SN - 1600-5775
VL - 28
IS - 3
SP - 824
EP - 833
PB - Wiley
CY - Oxford
AN - OPUS4-52491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Saloga, Patrick E. J.
A1 - Rybak, Tina
A1 - Thünemann, Andreas
T1 - Microwave-Assisted Synthesis of ZnO Nanoparticles: Phase Transfer to Water
N2 - Herein, a simple one-pot procedure is reported to obtain aqueous zinc oxide (ZnO) nanoparticle dispersions from ZnO nanoparticles dispersed in cyclohexane. In the process, polyoxyethylene (20) sorbitan monooleate (polysorbate 80, Tween 80) functions as a phase transfer agent and colloidal stabilizer. The particles grow in a defined manner during the transfer, presumably via coalescence. The final particle radii are tuneable in the range from 2.3 ± 0.1 nm to 5.7 ± 0.1 nm depending on the incubation time of the dispersion at 90 °C. Small-angle X-ray scattering is employed to determine the particle radius distributions before and after phase transfer. The larger ZnO particle radii are associated with a redshift of the optical bandgap and luminescence emission, as expected for semiconductor nanoparticles. The particles presented here exhibit a relative size distribution width of 20%, rendering them attractive for applications in, e.g., biology or catalysis. The latter application is demonstrated at the photocatalytic degradation of methylene blue dye.
KW - SAXS
KW - Small-angle X-ray scattering
KW - nanoparticle
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551502
DO - https://doi.org/10.1002/adem.202101276
VL - 24
IS - 6
SP - 1
EP - 7
PB - Wiley
AN - OPUS4-55150
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kinne, Marko
A1 - Schneider, Ronald
A1 - Thöns, Sebastian
T1 - Reconstructing Stress Resultants in Wind Turbine Towers Based on Strain Measurements
N2 - Support structures of offshore wind turbines are subject to cyclic stresses generated by different time-variant random loadings such as wind, waves, and currents in combinationwith the excitation by the rotor. In the design phase, the cyclic demand on wind turbine support structure is calculated and forecasted with semi or fully probabilistic engineering models. In some cases, additional cyclic stresses may be induced by construction deviations, unbalanced rotor masses and structural dynamic phenomena such as, for example, the Sommerfeld effect. Both, the significant uncertainties in the design and a validation of absence of unforeseen adverse dynamic phenomena necessitate the employment of measurement Systems on the support structures. The quality of the measurements of the cyclic demand on the support structures depends on (a) the precision of the measurement System consisting of sensors, amplifier and data normalization and (b) algorithms for analyzing and converting data to structural health information. This paper presents the probabilistic modelling and analysis of uncertainties in strain measurements performed for the purposes of reconstructing stress resultants in wind turbine towers.
It is shown how the uncertainties in the strain measurements affect the uncertainty in the individual components of the reconstructed forces and moments. The analysis identifies the components of the vector of stress resultants that can be reconstructed with sufficient precision.
T2 - International Conference on Uncertainty in Mechanical Engineering - ICUME
CY - Online meeting
DA - 07.06.2021
KW - Reconstruction of stress resultants
KW - Strain measurements
KW - Bayesian updating of measurement uncertainties
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527987
DO - https://doi.org/10.1007/978-3-030-77256-7_18
SP - 224
EP - 235
PB - Springer
AN - OPUS4-52798
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Maxi B.
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Loeschner, Katrin
A1 - Givelet, Lucas
A1 - Fahrenson, Christoph
A1 - Braeuning, Albert
A1 - Sieg, Holger
T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics
N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles.
KW - Toxicology
KW - Nanoparticles
KW - Dynamic Light Scattering
KW - Nanoplastics
KW - Microplastics
KW - Reference Method
KW - Reference Material
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947
DO - https://doi.org/10.1016/j.fct.2023.114423
SN - 0278-6915
VL - 184
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-59394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, Holger
A1 - Schaar, Caroline
A1 - Fouquet, Nicole
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Braeuning, Albert
T1 - Particulate iron oxide food colorants (E 172) during artificial digestion and their uptake and impact on intestinal cells
N2 - Iron oxide of various structures is frequently used as food colorant (E 172). The spectrum of colors ranges from yellow over orange, red, and brown to black, depending on the chemical structure of the material. E 172 is mostly sold as solid powder. Recent studies have demonstrated the presence of nanoscaled particles in E 172 samples, often to a very high extent. This makes it necessary to investigate the fate of these particles after oral uptake. In this study, 7 differently structured commercially available E 172 food colorants (2 x Yellow FeO(OH), 2 x Red Fe2O3, 1 x Orange Fe2O3 + FeO(OH) and 2 x Black Fe3O4) were investigated for particle dissolution, ion release, cellular uptake, crossing of the intestinal barrier and toxicological impact on intestinal cells. Dissolution was analyzed in water, cell culture medium and artificial digestion fluids. Small-angle X-ray scattering (SAXS) was employed for determination of the specific surface area of the colorants in the digestion fluids. Cellular uptake, transport and toxicological effects were studied using human differentiated Caco-2 cells as an in vitro model of the intestinal barrier. For all materials, a strong interaction with the intestinal cells was observed, albeit there was only a limited dissolution, and no toxic in vitro effects on human cells were recorded.
KW - Toxicology
KW - Nanoparticles
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593935
DO - https://doi.org/10.1016/j.tiv.2024.105772
VL - 96
SP - 1
EP - 12
PB - Elsevier BV
AN - OPUS4-59393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kinne, Marko
A1 - Thöns, Sebastian
T1 - Fatigue Reliability Based on Predicted Posterior Stress Ranges Determined from Strain Measurements of Wind Turbine Support Structures
N2 - In the present paper, an approach for updating the continuous stress range distribution of a welded connection of a wind turbine support structure with predicted information from strain measurements is presented. Environmental conditions, such as wind or, in offshore fields, waves and currents, in combination with rotor excitations generate cyclic stresses affecting the reliability of welded joints of the support structure over the service life. Using strain measurements, these conditions can be monitored, and the resulting stress ranges, under consideration of measurement, mechanical and material uncertainties, can be reconstructed. These stress ranges can be used as an input for updating the prior probability density function (PDF) of the stress ranges predicted by the overall dynamics and a detailed design analysis. Applying Bayesian probability theory and decision theoretical implications, the predicted posterior probability density of the stress ranges is calculated based on the design information and uncertainties. This approach is exemplified, and it is shown how the predicted stress ranges and the design stress ranges are distributed. The prior and the predicted posterior stress ranges are used for a reliability calculation for potentially entering a pre-posterior decision analysis
KW - Strain measurements of wind turbine support structures
KW - Bayesian updating of stress ranges
KW - Posterior fatigue reliability
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572663
DO - https://doi.org/10.3390/en16052225
VL - 16
IS - 5
SP - 1
EP - 26
PB - MDPI
AN - OPUS4-57266
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, Jana
A1 - Taubert, Andreas
A1 - Thünemann, Andreas
T1 - Synthesis and Characterization of Ultra‐Small Gold Nanoparticles in the Ionic Liquid 1‐Ethyl‐3‐methylimidazolium Dicyanamide, [Emim][DCA]
N2 - AbstractWe report on gold clusters with around 62 gold atoms and a diameter of 1.15±0.10 nm. Dispersions of the clusters are long‐term stable for two years at ambient conditions. The synthesis was performed by mixing tetrachloroauric acid (HAuCl4 ⋅ 3 H2O) with the ionic liquid 1‐ethyl‐3‐methylimidazolium dicyanamide ([Emim][DCA]) at temperatures of 20 to 80 °C. Characterization was performed with small‐angle X‐ray scattering (SAXS), UV‐Vis spectroscopy, and MALDI‐TOF mass spectrometry. A three‐stage model is proposed for the formation of the clusters, in which cluster growth from gold nuclei takes place according to the Lifshitz‐Slyozov‐Wagner (LSW) model followed by oriented attachment to form colloidal stable clusters.
KW - Reference materials
KW - SAXS
KW - Gold
KW - Nanoparticle
KW - Small-angle X-ray scattering
KW - Ionic liquid
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588203
DO - https://doi.org/10.1002/open.202300106
SN - 2191-1363
VL - 44
SP - 1
EP - 19
PB - Wiley
AN - OPUS4-58820
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, Jana
A1 - Thünemann, Andreas
T1 - Aqueous Dispersions of Polypropylene: Toward Reference Materials for Characterizing Nanoplastics
N2 - Microplastics and nanoplastics pollute the natural environment all over the world, but the full extent of the hazards posed by this waste is unclear. While research on microplastics is well advanced, little work has been done on nanoplastics. This discrepancy is mainly due to the lacking ability to detect nanoplastics in biologically and environmentally relevant matrices. Nanoplastics reference materials can help the development of suitable methods for identifying and quantifying nanoplastics in nature. The aim is to synthesize nanoplastics made from one of the most commonly used plastics, namely polypropylene. An easy way to produce long-term stable aqueous dispersions of polypropylene nanoparticles (nano polypropylene) is reported. The nanoplastic particles, prepared by mechanical breakdown, show a mean hydrodynamic diameter of D h = 180.5 ± 5.8 nm and a polydispersity index of PDI = 0.084 ± 0.02. No surfactant is needed to obtain dispersion which is stable for more than 6 months. The colloidal stability of the surfactant-free nano polypropylene dispersions is explained by their low zeta potential of 𝜻 = −43 ± 2 mV.
KW - Nanoparticles
KW - Reference Material
KW - Nanoplastics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571799
DO - https://doi.org/10.1002/marc.202200874
SN - 1022-1336
VL - 44
IS - 6
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57179
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kinne, Marko
A1 - Farhan, Muhammad
A1 - Schneider, Ronald
A1 - Thöns, Sebastian
T1 - Influence of the structural integrity management on the levelized cost of energy of offshore wind: a parametric sensitivity analysis
N2 - The levelized cost of energy (LCoE) is an important measure to quantify the macro-economic efficiency of an offshore wind farm and to enable a quantitative comparison with other types of energy production. The costs of the structural integrity management - which is required to ensure an adequate lifetime reliability of the turbine support structures - are part of the operational expenditures of an offshore wind farm. An optimization of the structural integrity management may reduce the operational expenditures and consequently the LCoE. However, the effect of the structural integrity management on the LCoE is hardly known. To investigate this effect, this paper presents a sensitivity analysis of the LCoE of a generic offshore wind farm. The probabilistic models of the parameters influencing the LCoE are based on a literature study including an explicit model for the structural integrity management.
The analysis reveals that LCoE may potentially be reduced if an optimization of the structural integrity management enables a service life extension.
T2 - International Probabilistic Workshop 2022
CY - Stellenbosch, South Africa
DA - 08.09.2022
KW - Structural integrity management
KW - Levelized cost of energy
KW - Sensitivity analysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572724
DO - https://doi.org/10.14311/APP.2022.36.0090
VL - 36
SP - 90
EP - 98
PB - Acta Polytechnica CTU Proceedings
AN - OPUS4-57272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sauermoser-Yri, M.
A1 - Veldurthi, N.
A1 - Wölfle, C. H.
A1 - Svartvatn, P. J.
A1 - Flo Hoem, S. O.
A1 - Lid, M. J.
A1 - Bock, Robert
A1 - Palko, J.
A1 - Torgersen, J.
T1 - On the porosity-dependent permeability and conductivity of triply periodic minimal surface based porous media
N2 - With the fast development in the field of additive manufacturing, triply periodic minimal surface (TPMS) based porous media have recently found many uses in mechanical property tuning. However, there is still a lack of understanding in their porosity-dependent permeability and electrical as well as thermal conductivity. Here, we perform finite volume simulations on the solid and void domains of the Schoen gyroid (SG), Schwarz primitive (SP) and Schwarz primitive beam (SPB) TPMS with porosities between 63% and 88% in Ansys Fluent. A simple cubic lattice (CL) of equivalent porosity served as reference. The SPB and CL showed up to one order of magnitude higher permeabilities than the SG and SP. However, SG and SP have about 1.3 and 2.6 times the electrical and thermal conductivity of SPB and CL, respectively. Furthermore, the properties of SPB and CL are largely affected by the surface area density, whereas tortuosity variation does not impact permeability and conductivity to a major extent. Finally, empirical relations are adapted to describe the presented data and thus, they may enable future designers of TPMS based porous structures to fine-tune the geometries according to the requirements on permeability and electrical as well as thermal conductivity.
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - Biomaterials
KW - Ceramics and Composites
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585250
DO - https://doi.org/10.1016/j.jmrt.2023.09.242
SN - 2238-7854
VL - 27
SP - 585
EP - 599
PB - Elsevier B.V.
AN - OPUS4-58525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hajhariri, Aliasghar
A1 - Eberwein, Robert
A1 - Perrone, Luca Pakj
A1 - Cozzani, Valerio
A1 - Otremba, Frank
A1 - Seidlitz, Holger
T1 - Study the impact of spacer at thermal degradation process of MLI-based insulation in fire condition
N2 - To reduce CO2 emissions, energy carriers such as hydrogen are considered to be a solution. Consumption of hydrogen as a fuel meets several limitations such as its low volumetric energy density in gas phase. To tackle this problem, storage as well as transportation in liquified phase is recommended. To be able to handle this component in liquid phase, an efficient thermal insulation e.g., MLI insulation is required. Different studies have been addressed the vulnerability of such insulation against high thermal loads e.g., in an accident engaging fire. Some of research works have highlighted the importance of considering the MLI thermal degradation focusing on its reflective layer. However, limited number of studies addressed the thermal degradation of spacer material and its effect on the overall heat flux.
In this study, through systematic experimental measurements, the effect of thermal loads on glass fleece, glass paper as well as polyester spacers are investigated. The results are reported in various temperature and heat flux profiles. Interpreting the temperature profiles revealed that, as the number of spacers in the medium increases, the peak temperature detectable by the temperature sensor on the measurement plate decreases. Each individual spacer contributes to mitigating the radiative energy received by the measurement plate. Stacks of 20–50 spacers (this is the number of layers in commercial MLI systems applied for liquid hydrogen applications) can potentially reduce the thermal radiation by 1–2 orders of magnitude.
An empirical correlation to predict a heat flux attenuation factor is proposed, which is useful for further numerical and analytical studies in the temperature range from ambient to 300 ◦C.
KW - Cryogenic
KW - Liquid Hydrogen
KW - Multi-Layer Insultation
KW - Heat Transfer
KW - Hydrogen Storage Safety
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614919
DO - https://doi.org/10.1016/j.jlp.2024.105461
SN - 0950-4230
VL - 92
SP - 1
EP - 7
PB - Elsevier Ltd.
AN - OPUS4-61491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Chianese, Carmela
A1 - Hajhariri, Aliasghar
A1 - Eberwein, Robert
A1 - Otremba, Frank
A1 - Cozzani, Valerio
T1 - Modeling the performance of multilayer insulation in cryogenic tanks undergoing external fire scenarios
N2 - Multilayer Insulation (MLI) is frequently used in vacuum conditions for the thermal insulation of cryogenic storage tanks. The severe consequences of the degradation of such materials in engulfing fire scenarios were recently evidenced by several large-scale experimental tests. In the present study, an innovative modelling approach was developed to assess the performance of heat transfer in polyester-based MLI materials for cryogenic applications under fire conditions. A specific layer-by-layer approach was integrated with an apparent kinetic thermal degradation model based on thermogravimetric analysis results. The modeling results provided a realistic simulation of the experimental data obtained by High-Temperature Thermal Vacuum Chamber tests reproducing fire exposure conditions. The model was then applied to assess the behavior of MLI systems for liquid hydrogen tanks in realistic fire scenarios. The results show that in intense fire scenarios degradation occurs rapidly, compromising the thermal insulation performances of the system within a few minutes.
KW - Multilayer Insulation
KW - Cryogenic Vessels
KW - Liquefied Hydrogen
KW - Liquefied Natural Gas
KW - Safety
KW - Fire
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599418
DO - https://doi.org/10.1016/j.psep.2024.04.061
SN - 0957-5820
VL - 186
SP - 1169
EP - 1182
PB - Elsevier B.V.
AN - OPUS4-59941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Theiler, Geraldine
A1 - Gradt, Thomas
T1 - Comparison of the sliding behavior of several polymers in gaseous and liquid hydrogen
N2 - The development of hydrogen technologies entails high safety requirements in distribution and dispensing infrastructure. Therefore, it is necessary to pursue research on material compatibility in hydrogen, especially for critical parts with tribological issues.
The focus of this study is to evaluate the influence of hydrogen on a wider range of commercially available polymer materials. Thereby, the friction and wear behavior of different grades of TPE, POM, PA66, PA12, PPA, PEEK, PPS, PTFE, PAI, PI and PBI were investigated against a rotating steel disk (AISI 304). Filled and unfilled polymers from different suppliers were evaluated at room temperature in air, vacuum and hydrogen gas (H2) as well as in liquid hydrogen at - 253°C (LH2).
The sliding behavior of the polymer materials is discussed by means of surface analyses, whereby special attention is paid to the formation of a transfer film.
According to the results at ambient temperature, the effect of hydrogen environment on the tribological behavior of neat polymers may be related to lack of moisture, but also to saturated hydrocarbons in gaseous hydrogen. In liquid hydrogen, the best tribological performances were achieved with neat PA polymers as well as PPS and PI composites.
KW - Polymers
KW - Composites
KW - Sliding wear
KW - Hydrogen
KW - Cryogenic temperature
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597123
DO - https://doi.org/10.2474/trol.18.217
SN - 1881-2198
VL - 18
IS - 5
SP - 217
EP - 231
PB - Japanese Society of Tribologists
AN - OPUS4-59712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Theiler, Geraldine
A1 - Gradt, Thomas
T1 - Influence of counterface and environment on the tribological behaviour of polymer materials
N2 - This paper focuses on the influence of the counterface materials on the sliding behaviour of polymer materials in hydrogen. Polyimide (PI), polyetheretherketone (PEEK) and Polytetrafluoroethylene (PTFE) materials were investigated against hardened 52100 martensitic bearing steel and 304 austenitic stainless steel with similar roughness (Ra = 0.2 μm). Results indicate that the friction and wear of PI and PEEK materials depend on the counterface material. This effect wasn’t observed for PTFE composites. While the tribological performance of polyimide is better against 52100 in hydrogen, improved sliding behaviour of PEEK materials is observed with 304 counterface, particularly at higher sliding speed. Surface analyses of the transfer film reveal that the influence of the counterface is primarily related to the chemical nature of the steel for PI and to the thermal conductivity of the disc for PEEK materials.
KW - Friction
KW - Wear
KW - Polymers
KW - Hydrogen Transfer Film
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515483
DO - https://doi.org/10.1016/j.polymertesting.2020.106912
VL - 93
SP - 106912
PB - Elsevier Ltd.
AN - OPUS4-51548
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Tiebe, Carlo
A1 - Davenport, John
A1 - Lorek, Andreas
A1 - Garland, Stephen
A1 - Schwanke, Volker
A1 - Wernecke, Roland
T1 - Gasfeuchtemessung in der Normung
N2 - Schwefelhexafluorid (SF6) ist ein 22.800-mal stärkeres Treibhausgas als CO2, wird aber aufgrund seiner isolierenden Eigenschaften in Mittel- und Hochspannungssystemen wie Schaltanlagen eingesetzt. Voraussetzung für die Durchschlagfestigkeit ist ein geringer Wasserdampfgehalt. Viele aktuelle Feuchtigkeitssensoren zeigen jedoch eine Querempfindlichkeit gegenüber CO2. Diese Richtlinienarbeit zielt darauf ab, den aktuellen Stand der Technik zu erweitern und neue Erkenntnisse zu gewinnen. Abschließend erfolgt eine Erweiterung der Richtlinie zur Gasfeuchte-Messung VDI/VDE 3514.
T2 - GMA/ITG – Fachtagung Sensoren und Messsysteme 2024
CY - Nuremberg, Germany
DA - 11.06.2024
KW - Gassensorik
KW - Industrienormen
KW - SF6
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604597
DO - https://doi.org/10.5162/sensoren2024/P32
SP - 547
EP - 549
PB - GMA/ITG – Fachtagung Sensoren und Messsysteme 2024
CY - Nürnberg
AN - OPUS4-60459
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Giannakopoulos, Antonios E.
A1 - Zisis, Athanasios
A1 - Zervaki, Anna D.
A1 - Dimopoulos, Christos D.
A1 - Platypodis, Efstathios
A1 - Eberwein, Robert
T1 - Effective elastic moduli and failure mechanisms of a random assembly of thin walled glass microbubbles
N2 - In this work a methodology is presented to estimate the elastic properties and failure mechanisms of an assembly of random, brittle microbubbles. The approach is based on the mechanics of frictionless micro-contact between hollow spherical shells by employing relations from classical shell theory and verified by two dimensional axisymmetric Finite Elements. The estimated values are in agreement with available experimental values. Moreover, a granular type analytical homogenization model provides an isotropic elastic constitutive law to be used for the macroscopic deformation of an assembly of glass micro-bubbles when it is compressed by external loads. In addition, approximate estimates are also proposed for two important micro-failure mechanisms of such assemblies that relate either to the splitting or to the buckling of a brittle spherical shell, prior its complete crushing. The results are novel and are expected to enhance the application of glass microbubbles directly in acute thermal insulation problems such as liquid hydrogen storage.
KW - LH2
KW - Cryogenic Vessels
KW - Insulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634354
DO - https://doi.org/10.1016/j.ijsolstr.2025.113528
SN - 0020-7683
VL - 320
SP - 1
EP - 11
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-63435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menzel, M.
A1 - Scharf, O.
A1 - Novak, S.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Hischenhuber, P.
A1 - Buzanich, Günter
A1 - Meyer, A.
A1 - Lopez, V.
A1 - McIntosh, K.
A1 - Streli, C.
A1 - Havrilla, G.
A1 - Fittschen, U.
T1 - Shading in TXRF: calculations and experimental validation using a color X-ray camera
N2 - Absorption effects in total reflection X-ray fluorescence (TXRF) analysis are important to consider, especially if external calibration is to be applied. With a color X-ray camera (CXC), that enables spatially and energy resolved XRF analysis, the absorption of the primary beam was directly visualized for mL-droplets and an array of pL-droplets printed on a Si-wafer with drop-on-demand technology. As expected, deposits that are hit by the primary beam first shade subsequent droplets, leading to a diminished XRF signal. This shading effect was quantified with enhanced precision making use of sub-pixel analysis that improves the spatial resolution of the camera. The measured absorption was compared to simulated results using three different model calculations. It was found they match very well (average deviation < 10%). Thus errors in quantification due to absorption effects can be accounted for in a more accurate manner.
KW - absorption
KW - X-ray Fluorescence analysis
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-359000
DO - https://doi.org/10.1039/C5JA00127G
IS - 10
SP - 2184
EP - 2193
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-35900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Hahn, Oliver
A1 - Denker, A.
A1 - Merchel, S.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Wolff, T.
ED - Armbruster, B.
ED - Eilbracht, H.
ED - Hahn, Oliver
ED - Heinrich-Tamaska, O.
T1 - Zerstörungsfreie Analyse von Metallartefakten - Eine Fallstudie
N2 - Die naturwissenschaftliche Analyse historischer Materialen ermöglicht die Beantwortung kulturhistorischer Fragestellungen, die mit kunsthistorischen oder archäologischen Ansätzen allein nicht zu leisten sind. In dieser Studie wurden sechs römische Münzen mit unterschiedlich stark ausgeprägten Korrosionsschichten an unbehandelten und polierten Stellen mit vier zerstörungsfreien analytischen Methoden untersucht: Hoch- und Niederenergie Protonen Induzierter Röntgenemission (HE-/PIXE), Synchrotronstrahlungsinduzierte-Röntgenfluoreszenzanalyse (SY-RFA) und Mikro-Röntgenfluoreszenzanalyse (Mikro-RFA) mit einem mobilen Gerät. Aufgrund von Unterschieden in den Messbedingungen und dem Einfluss der Patina-Schichten auf diese ergaben sich nur für wenige Elemente Übereinstimmungen in den quantitativen Daten. Zur Validierung zukünftiger Messkampagnen mit verschiedenen Methoden sind daher Vergleichstudien unerlässlich.
N2 - Investigations of physical properties and chemical composition of ancient materials generate important data for answering culture-historical questions that cannot be solved by art historical and archaeological methods alone. This contribution reports on the analysis of six Roman coins, with different degrees of corrosion layers in parts that were not handled or polished, using four non-destructive methods: low-energy particle-induced X-ray emission (PIXE, 2 MeV), high-energy PIXE (68 MeV), μ-X-ray fluorescence (XRF) spectrometry with a portable device and synchrotron-radiation induced XRF. Because of differences in the conditions needed for measurement and the influence of the layers of patina on these measurements, there were few elements where the quantitative data were in agreement. Thus comparative analyses are essential to validate future measurement projects using different methods.
KW - Zerstörungsfreie Prüfung
KW - Protoneninduzierte Röntgenemission
KW - Röntgenfluoreszenzanalyse
KW - Non-destructive testing
KW - Particle-induced X-ray emission
KW - X-ray fluorescence analysis
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-385702
SN - 978-3-9816751-5-3
VL - Berlin studies of the ancient world, Band 35
SP - 117
EP - 137
PB - Edition Topoi
CY - Berlin
AN - OPUS4-38570
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nowak, S.H.
A1 - Bjeoumikhov, A.
A1 - Von Borany, J.
A1 - Buchriegler, J.
A1 - Munnik, F.
A1 - Petric, M.
A1 - Radtke, Martin
A1 - Renno, A.D.
A1 - Reinholz, Uwe
A1 - Scharf, O.
A1 - Wedell, R.
T1 - Sub-pixel resolution with a color X-ray camera
N2 - The color X-ray camera SLcam® is a full-field, single photon detector providing scanning-free, energy and spatially resolved X-ray imaging. Spatial resolution is achieved with the use of polycapillary optics guiding X-ray photons from small regions on a sample to distinct energy dispersive pixels on a charged-coupled device detector. Applying sub-pixel resolution, signals from individual capillary channels can be distinguished. Therefore, the SLcam® spatial resolution, which is normally limited to the pixel size of the charge-coupled device, can be improved to the size of individual polycapillary channels. In this work a new approach to a sub-pixel resolution algorithm comprising photon events also from the pixel centers is proposed. The details of the employed numerical method and several sub-pixel resolution examples are presented and discussed.
KW - Color X-ray camera
KW - Sub pixel analysis
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334948
DO - https://doi.org/10.1039/c5ja00028a
SN - 0267-9477
SN - 1364-5544
SP - 1890
EP - 1897
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-33494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachmöller, O.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Aichler, M.
A1 - Radtke, Martin
A1 - Dietrich, D.
A1 - Schwamborn, K.
A1 - Lutz, L.
A1 - Werner, M.
A1 - Sperling, M.
A1 - Walch, A.
A1 - Karst, U.
T1 - Elemental bioimaging and speciation analysis for the investigation of Wilsons disease using μXRF and XANES
N2 - A liver biopsy specimen from a Wilson’s disease (WD) patient was analyzed by means of micro-X-ray fluorescence (mXRF) spectroscopy to determine the elemental distribution. First, bench-top mXRF was utilized for a coarse scan of the sample under laboratory conditions. The resulting distribution maps of copper and iron enabled the determination of a region of interest (ROI) for further analysis. In order to obtain more detailed elemental information, this ROI was analyzed by synchrotron radiation (SR)-based mXRF with a beam size of 4 mm offering a resolution at the cellular level. Distribution maps of additional elements to copper and iron like zinc and manganese were obtained due to a higher sensitivity of SR-mXRF. In addition to this, X-ray absorption near edge structure spectroscopy (XANES) was performed to identify the oxidation states of copper in WD. This speciation analysis indicated a mixture of copper(I) and copper(II) within the WD liver tissue.
KW - progressive hepatolenticular degeneration
KW - mXRF Micro-X-ray fluorescence spectroscopy
KW - XANES X-ray absorption near edge structure spectroscopy
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-360811
DO - https://doi.org/10.1039/C6MT00001K
SN - 1756-5901
SN - 1756-591X
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-36081
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mundra, S.
A1 - Bernal, S. A.
A1 - Criado, M.
A1 - Hlaváček, Petr
A1 - Ebell, Gino
A1 - Reinemann, Steffi
A1 - Gluth, Gregor
A1 - Provis, J. L.
T1 - Steel corrosion in reinforced alkali‐activated materials
N2 - The development of alkali‐activated materials (AAMs) as an alternative to Portland cement (PC) has seen significant progress in the past decades. However, there still remains significant uncertainty regarding their long term performance when used in steel‐reinforced structures. The durability of AAMs in such applications depends strongly on the corrosion behaviour of the embedded steel reinforcement, and the experimental data in the literature are limited and in some cases inconsistent. This letter elucidates the role of the chemistry of AAMs on the mechanisms governing passivation and chloride‐induced corrosion of the steel reinforcement, to bring a better understanding of the durability of AAM structures exposed to chloride. The corrosion of the steel reinforcement in AAMs differs significantly from observations in PC; the onset of pitting (or the chloride ‘threshold’ value) depends strongly on the alkalinity, and the redox environment, of these binders. Classifications or standards used to assess the severity of steel corrosion in PC appear not to be directly applicable to AAMs due to important differences in pore solution chemistry and phase assemblage.
KW - Corrosion
KW - Alkali-activated
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435162
DO - https://doi.org/10.21809/rilemtechlett.2017.39
SN - 2518-0231
VL - 2
SP - 33
EP - 39
PB - RILEM Publications SARL
CY - Paris, France
AN - OPUS4-43516
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Guerra, M. F.
A1 - Fischer, M.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
T1 - Inca figurines from the Ethnologisches Museum in Berlin: an analytical study of some typical and atypical productions
N2 - Fourteen hollow and one cast anthropomorphic and zoomorphic figurines produced in Incan times for ritual offerings from the Ethnologisches Museum in Berlin were selected to investigate the technologies and alloys used for their fabrication with portable optical microscopy and non-destructive XRF elemental analysis. This group of gold and silver figurines includes typical specimens of the Inca production, such as the four silver figurines from the Island Coati in Lake Titicaca and the two gold figurines from Pachacamac, as well as specimens that are seldom present in collections, which makes them atypical. In addition to the tall figurines with atypical hair or standing pose, one bicolour figurine half silver, half gold) and another with coloured inlays were included in this study for comparison. The large majority of the silver specimens are made from very high quality alloys and the gold figurines are made from alloys containing low copper contents and silver ranging from 30wt% to 52wt%.
KW - Gold
KW - pXRF
KW - Inca
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436015
DO - https://doi.org/10.4000/bifea.8232
SN - 0303-7495
VL - 46
IS - 1
SP - 221
EP - 251
PB - Institut Français d'Études Andines
AN - OPUS4-43601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Greiser, Sebastian
A1 - Gluth, Gregor
A1 - Sturm, Patrick
A1 - Jäger, Christian
T1 - 29Si{27Al}, 27Al{29Si} and 27Al{1H} double-resonance NMR spectroscopy study of cementitious sodium aluminosilicate gels (geopolymers) and gel-zeolite composites
N2 - The influence of starting materials and synthesis route on the properties and the structure of cementitious sodium aluminosilicate gels is not fully understood, partly due their amorphous nature and the fact that they often contain residual reactants, which can make the results of single-pulse NMR spectroscopy applied to these materials difficult to interpret or ambiguous. To overcome some of these limitations, 29Si{27Al} TRAPDOR NMR as well as 27Al{29Si} and 27Al{1H} REDOR NMR spectroscopy were applied to materials synthesized by the one-part alkali-activation route from three different amorphous silica starting materials, including rice husk ash. The latter led to formation of a fully amorphous sodium aluminosilicate gel (geopolymer), while the materials produced from the other silicas contained amorphous phase and crystalline zeolites. Application of the double-resonance NMR methods allowed to identify hydrous alumina gel domains in the rice husk ash-based material as well as significantly differing amounts of residual silica in the three cured materials. Four-coordinated Al existed not only in the aluminosilicate gel framework but also in a water-rich chemical environment with only a small amount of Si in proximity, likely in the alumina gel or possibly present as extra-framework Al in the aluminosilicate gel. The results demonstrate how the employment of different silica starting materials determines the phase assemblage of one-part alkali-activated materials, which in turn influences their engineering properties such as the resistance against chemically/biologically aggressive media.
KW - Alkali-activated materials
KW - Solid-state NMR
KW - Aluminium hydroxide
KW - Rice husk ash
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-469353
DO - https://doi.org/10.1039/C8RA09246J
SN - 2046-2069
VL - 8
IS - 70
SP - 40164
EP - 40171
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-46935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Gluth, Gregor
A1 - Hlavacek, Petr
A1 - Reinemann, Steffi
A1 - Ebell, Gino
A1 - Mietz, Jürgen
ED - Alexander, M.G.
ED - Beushausen, H.
ED - Dehn, F.
ED - Moyo, P.
T1 - Leaching, carbonation and chloride ingress in reinforced alkali-activated fly ash mortars
N2 - Alkali-activated fly ash mortars were studied with regard to durability-relevant transport coefficients and the electrochemical behaviour of embedded carbon steel bars on exposure of the mortars to leaching, carbonation and chloride penetration environments. The transport coefficients differed considerably between different formulations, being lowest for a mortar with BFS addition, but still acceptable for one of the purely fly ash-based mortars. Leaching over a period of ~300 days in de-ionized water did not lead to observable corrosion of the embedded steel, as shown by the electrochemical data and visual inspection of the steel. Exposure to 100 % CO2 atmosphere caused steel depassivation within approx. two weeks; in addition, indications of a deterioration of the mortar were observed. The results are discussed in the context of the different reaction products expected in high- and low-Ca alkali-activated binders, and the alterations caused by leaching and carbonation.
T2 - International Conference on Concrete Repair, Rehabilitation and Retrofitting (ICCRRR 2018)
CY - Cape Town, South Africa
DA - 19.11.2018
KW - Alkali-activated materials
KW - Steel corrosion
KW - Leaching
KW - Carbonation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-464381
DO - https://doi.org/10.1051/matecconf/201819902025
VL - 199
SP - Article Number 02025
PB - EDP Sciences
AN - OPUS4-46438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rauwolf, M.
A1 - Turyanskaya, A.
A1 - Roschger, A.
A1 - Prost, J.
A1 - Simon, R.
A1 - Scharf, O.
A1 - Radtke, Martin
A1 - Schoonjans, Tom
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Klaushofer, K.
A1 - Wobrauschek, P.
A1 - Hofstaetter, J. G.
A1 - Roschger, P.
A1 - Streli, C.
T1 - Synchrotron radiation micro X-ray fluorescence spectroscopy of thin structures in bone samples: comparison of confocal and color X-ray camera setups
N2 - In the quest for finding the ideal synchrotron-radiation-induced imaging method for the investigation of trace element distributions in human bone samples, experiments were performed using both a scanning confocal synchrotron radiation micro X-ray fluorescence (SR-mXRF) (FLUO beamline at ANKA) setup and a full-field color X-ray camera (BAMline at BESSY-II) setup. As zinc is a trace element of special interest in bone, the setups were optimized for its detection. The setups were compared with respect to count rate, required measurement time and spatial resolution. It was demonstrated that the ideal method depends on the element of interest. Although for Ca (a major constituent of the bone with a low energy of 3.69 keV for its K alpha XRF line) the color X-ray camera provided a higher resolution in the plane, for Zn (a trace element in bone) only the confocal SR-µXRF setup was able to sufficiently image the distribution.
KW - Synchrotron
KW - BAMline
KW - BESSY
KW - XRF
KW - X-ray Color Camera
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391944
DO - https://doi.org/10.1107/S1600577516017057
SN - 1600-5775
VL - 24
SP - 307
EP - 311
PB - International Union of Crystallography
AN - OPUS4-39194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Grengg, C.
A1 - Ukrainczyk, N.
A1 - Mittermayr, F.
A1 - Dietzel, M.
T1 - Acid resistance of alkali-activated materials: Recent advances and research needs
N2 - Cementitious materials are frequently applied in environments in which they are exposed to acid attack, e.g., in sewer systems, biogas plants, and agricultural/food-related industries. Alkali-activated materials (AAMs) have repeatedly been shown to exhibit a remarkably high resistance against attack by organic and inorganic acids and, thus, are promising candidates for the construction and the repair of acid-exposed structures. However, the reaction mechanisms and processes affecting the acid resistance of AAMs have just recently begun to be understood in more detail. The present contribution synthesises these advances and outlines potentially fruitful avenues of research. The interaction between AAMs and acids proceeds in a multistep process wherein different aspects of deterioration extend to different depths, complicating the overall determination of acid resistance. Partly due to this indistinct definition of the ‘depth of corrosion’, the effects of the composition of AAMs on their acid resistance cannot be unambiguously identified to date. Important parallels exist between the deterioration of low-Ca AAMs and the weathering/corrosion of minerals and glasses (dissolution-reprecipitation mechanism). Additional research requirements relate to the deterioration mechanism of high-Ca AAMs; how the character of the corroded layer influences the rate of deterioration; the effects of shrinkage and the bond between AAMs and substrates.
KW - Alkali-activated materials
KW - Acid attack
KW - Acid resistance
KW - Concrete repair
KW - MIC
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557376
DO - https://doi.org/10.21809/rilemtechlett.2022.157
SN - 2518-0231
VL - 7
SP - 58
EP - 67
PB - RILEM Publications SARL
CY - Paris
AN - OPUS4-55737
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, Ricky
A1 - Sturm, Patrick
A1 - Geddes, D.A.
A1 - Keßler, S.
A1 - Walkley, B.
A1 - Gluth, Gregor
T1 - The influence of curing temperature on the strength and phase assemblage of hybrid cements based on GGBFS/FA blends
N2 - Hybrid cements are composites made of Portland cement or Portland clinker and one or more supplementary cementitious materials like slag, fly ash or metakaolin, activated with an alkali salt. To date, their hydration mechanism and the phase formation at various temperatures is insufficiently understood, partly due to the large variability of the raw materials used. In the present study, three hybrid cements based on ground granulated blast furnace slag, fly ash, Portland clinker and sodium sulfate, and an alkali-activated slag/fly ash blend were cured at 10 and 21.5°C, and subsequently analyzed by XRD, 27Al MAS NMR, and TGA. The compressive strength of the hybrid cements was higher by up to 27% after 91-day curing at 10°C, compared to curing at 21.5°C. The experimental results as well as thermodynamic modeling indicate that the differences in compressive strength were related to a different phase assemblage, mainly differing amounts of strätlingite and C-N-A-S-H, and the associated differences of the volume of hydration products. While the strätlingite was amorphous to X-rays, it could be identified by 27Al MAS NMR spectroscopy, TGA and thermodynamic modeling. The microstructural properties of the hybrid cements and the alkali-activated slag/fly ash blend as well as the compatibility between thermodynamic modeling results and experimental data as a function of curing temperature and time are discussed.
KW - Hybrid cements
KW - Strätlingite
KW - Thermodynamic modelling
KW - Hydration
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557767
DO - https://doi.org/10.3389/fmats.2022.982568
SN - 2296-8016
VL - 9
SP - 1
EP - 16
PB - Frontiers
AN - OPUS4-55776
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de O. Primo, J.
A1 - Horsth, D.F.
A1 - de S. Correa, J.
A1 - Das, A.
A1 - Bittencourt, C.
A1 - Umek, P.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Yusenko, Kirill
A1 - Zanetta, C.
A1 - Anaissi, F.J.
T1 - Synthesis and Characterization of Ag/ZnO Nanoparticles for Bacteria Disinfection in Water
N2 - n this study, two green synthesis routes were used for the synthesis of Ag/ZnO nanoparticles, using cassava starch as a simple and low-cost effective fuel and Aloe vera as a reducing and stabilizing agent. The Ag/ZnO nanoparticles were characterized and used for bacterial dis-
infection of lake water contaminated with Escherichia coli (E. coli). Characterization indicated the formation of a face-centered cubic structure of metallic silver nanoparticles with no insertion of Ag into the ZnO hexagonal wurtzite structure. Physicochemical and bacteriological analyses described in “Standard Methods for the Examination of Water and Wastewater” were used to evaluate the efficiency of the treatment. In comparison to pure ZnO, the synthesized Ag/ZnO nanoparticles showed high efficiencies against Escherichia coli (E. coli) and general coliforms present in the lake
water. These pathogens were absent after treatment using Ag/ZnO nanoparticles. The results indicate that Ag/ZnO nanoparticles synthesized via green chemistry are a promising candidate for the treatment of wastewaters contaminated by bacteria, due to their facile preparation, low-cost synthesis,and disinfection efficiency.
KW - Synchrotron
KW - BAMline
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562440
DO - https://doi.org/10.3390/nano12101764
SN - 2079-4991
VL - 12
IS - 10
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-56244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Ke, X.
A1 - Vollpracht, A.
A1 - Weiler, L.
A1 - Bernal, S. A.
A1 - Cyr, M.
A1 - Dombrowski-Daube, K.
A1 - Geddes, D. A.
A1 - Grengg, C.
A1 - Le Galliard, C.
A1 - Nedeljkovic, M.
A1 - Provis, J. L.
A1 - Valentini, L.
A1 - Walkley, B.
T1 - Carbonation rate of alkali-activated concretes and high-volume SCM concretes: a literature data analysis by RILEM TC 281-CCC
N2 - The current understanding of the carbonation and the prediction of the carbonation rate of alkali-activated concretes is complicated inter alia by the wide range of binder chemistries used and testing conditions adopted. To overcome some of the limitations of individual studies and to identify general correlations between mix design parameters and carbonation resistance, the RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ Working Group 6 compiled and analysed carbonation data for alkali-activated concretes and mortars from the literature. For comparison purposes, data for blended Portland cement-based concretes with a high percentage of SCMs (≥ 66% of the binder) were also included in the database. The analysis indicates that water/CaO ratio and water/binder ratio exert an influence on the carbonation resistance of alkali-activated concretes; however, these parameters are not good indicators of the carbonation resistance when considered individually. A better indicator of the carbonation resistance of alkali-activated concretes under conditions approximating natural carbonation appears to be their water/(CaO + MgOeq + Na2Oeq + K2Oeq) ratio, where the subscript ‘eq’ indicates an equivalent amount based on molar masses. Nevertheless, this ratio can serve as approximate indicator at best, as other parameters also affect the carbonation resistance of alkali-activated concretes. In addition, the analysis of the database points to peculiarities of accelerated tests using elevated CO2 concentrations for low-Ca alkali-activated concretes, indicating that even at the relatively modest concentration of 1% CO2, accelerated testing may lead to inaccurate predictions of the carbonation resistance under natural exposure conditions.
KW - Alkali-activated materials
KW - Durability
KW - Carbonation
KW - Accelerated testing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560037
DO - https://doi.org/10.1617/s11527-022-02041-4
VL - 55
IS - 8
SP - 1
EP - 15
PB - Springer Nature
AN - OPUS4-56003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dubey, A.
A1 - Hon Keat, C.
A1 - Shvartsman, V.
A1 - Yusenko, Kirill
A1 - Escobar, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Hagemann, U.
A1 - Kovalenko, S.
A1 - Stächler, J.
A1 - Lupascu, D.
T1 - Mono-, Di-, and Tri-valent Cation Doped BiFe0.95Mn0.05O3 Nanoparticles: Ferroelectric Photocatalysts
N2 - The ferroelectricity of multivalent co-doped Bismuth ferrite (BiFeO3; BFO) nanoparticles (NPs) is revealed and utilized for light photocatalysis exploiting their narrow electronic band gap. The photocatalytic activity of ferroelectric photocatalysts BiFe0.95Mn0.05O3 (BFM) NPs and mono-, di-, or tri-valent cations (Ag+, Ca2+, Dy3+; MDT) co-incorporated BFM NPs are studied under ultrasonication and in acidic conditions. We find that such doping enhances the photocatalytic activity of the ferroelectric NPs approximately three times. The correlation of the photocatalytic activity with structural, optical, and electrical properties of the doped NPs is established. The increase of spontaneous polarization by the mono- and tri-valent doping is one of the major factors in enhancing the photocatalytic performance along with other factors such as stronger light absorption in the visible range, low recombination rate of charge carriers and larger surface area of NPs. A-site doping of BFO NPs by divalent elements suppresses the polarization, whereas trivalent (Dy3+) and monovalent (Ag+) cations provide an increase of polarization. The depolarization field in these single domain NPs acts as a driving force to mitigate recombination of the photoinduced charge carriers.
KW - Piezoresponse
KW - Bismuth Ferrite
KW - Nanoparticles
KW - Photocatalysis
KW - Ferroelectric
KW - Polarization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557230
DO - https://doi.org/10.1002/adfm.202207105
SN - 1616-301X
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-55723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Bertmer, M.
A1 - Gluth, Gregor
T1 - Sol–gel synthesis and characterization of lithium aluminate (L–A–H) and lithium aluminosilicate (L–A–S–H) gels
N2 - Hydrous lithium aluminosilicate (L–A–S–H) and lithium aluminate (L–A–H) gels are candidate precursors for glass-ceramics and ceramics with potential advantages over conventional processing routes. However, their structure before calcination remained largely unknown, despite the importance of precursor structure on the properties of the resulting materials. In the present study, it is demonstrated that L–A–S–H and L–A–H gels with Li/Al ≤ 1 can be produced via an organic steric entrapment route, while higher Li/Al ratios lead to crystallization of gibbsite or nordstrandite. The composition and the structure of the gels was studied by thermogravimetric analysis, X-ray diffraction, 27Al and 29Si magic-angle spinning nuclear magnetic resonance, and Raman spectroscopy. Aluminium was found to be almost exclusively in six-fold coordination in both the L–A–H and the L–A–S–H gels. Silicon in the L–A–S–H gels was mainly in Q4 sites and to a lesser extent in Q3 sites (four-fold coordination with no Si–O–Al bonds). The results thus indicate that silica-rich and aluminium-rich domains formed in these gels.
KW - Lithium aluminosilicates
KW - Raman spectroscopy
KW - Sol-gel
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558756
DO - https://doi.org/10.1111/ijac.14187
SN - 1546-542X
VL - 19
IS - 6
SP - 3179
EP - 3190
PB - Wiley
AN - OPUS4-55875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Margreiter, R.
A1 - Baumann, J.
A1 - Mantouvalou, I.
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Strub, E.
T1 - Investigations on fire-gilding
N2 - Fire-gilding is a historic technique for the application of golden layers on a number of different base materials utilizing a gold amalgam. This technique leaves a significant amount of Hg in the golden layer, giving archeometrists a reliable indicator to identify firegildings.
Recent findings on presumably fire-gilded objects have shown in several cases significantly lower Hg content than previously studied objects. This prompted a synchrotron-based X-ray fluorescence investigation into the Hg distribution along the material–gilding interface, as well as a series of measurements regarding the Hg content development in fire-gilded samples during artificial aging. This work presents findings on laboratory-prepared fire-gildings, indicating an Hg enrichment at the interface of firegilded silver samples. Notably, such an enrichment is missing in fire-gilded copper samples. Further, it is confirmed that fire-gilded layers typically do not undercut an Hg bulk content of 5%. In this light, it seems improbable that ancient samples that contain <5% Hg are fire-gilded. The results presented in this study might lead to a non-destructive method to identify the Hg enrichment at the interface. This might be obtained by a combination of different non-destructive measurements and might also work unambiguously in samples in which the gold top layer is altered.
KW - BAMline
KW - X-Ray Fluorescence
KW - Gilding
KW - Depth profile
KW - Archaeometry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552885
DO - https://doi.org/10.1111/arcm.12797
SN - 0003-813X
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-55288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Iro, M.
A1 - Ingerle, D.
A1 - Radtke, Martin
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Kregsamer, P.
A1 - Streli, C.
T1 - Investigation of polycapillary half lenses for quantitative confocal micro-X-ray fluorescence analysis
N2 - The use of polycapillary optics in confocal micro-X-ray fluorescence analysis (CMXRF) enables the destruction-free 3D investigation of the elemental composition of samples. The energy-dependent transmission properties, concerning intensity and spatial beam propagation of three polycapillary half lenses, which are vital for the quantitative interpretation of such CMXRF measurements, are investigated in a monochromatic confocal laboratory setup at the Atominstitut of TU Wien, and a synchrotron setup on the BAMline beamline at the BESSY II Synchrotron, Helmholtz-Zentrum-Berlin. The empirically established results, concerning the intensity of the transmitted beam, are compared with theoretical values calculated with the polycap software package and a newly presented analytical model for the transmission function.
The resulting form of the newly modelled energy-dependent transmission function is shown to be in good agreement with Monte Carlo simulated results for the complete energy regime, as well as the empirically established results for the energy regime between 6 keV and 20 keV. An analysis of possible fabrication errors was conducted via pinhole scans showing only minor fabrication errors in two of the investigated polycapillary optics. The energy-dependent focal spot size of the primary polycapillary was investigated in the laboratory via the channel-wise evaluation of knife-edge scans. Experimental results are compared with data given by the manufacturer as well as geometric estimations for the minimal focal spot size. Again, the resulting measurement points show a trend in agreement with geometrically estimated results and manufacturer data.
KW - BAMline
KW - Synchrotron
KW - Capillary
KW - confocal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562430
DO - https://doi.org/10.1107/S1600577522009699
SN - 1600-5775
VL - 29
SP - 1376
EP - 1384
PB - International Union of Crystallography
CY - Chester
AN - OPUS4-56243
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dobosy, Péter
A1 - Nguyen, Hoang Thi Phuong
A1 - Záray, Gyula
A1 - Streli, Christina
A1 - Ingerle, Dieter
A1 - Ziegler, Philipp
A1 - Radtke, Martin
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Endrédi, Anett
A1 - Fodor, Ferenc
T1 - Effect of iodine species on biofortification of iodine in cabbage plants cultivated in hydroponic cultures
N2 - Iodine is an essential trace element in the human diet because it is involved in the synthesis of thyroid hormones. Iodine deficiency affects over 2.2 billion people worldwide, making it a significant challenge to find plant-based sources of iodine that meet the recommended daily intake of this trace element. In this study, cabbage plants were cultivated in a hydroponic system containing iodine at concentrations ranging from 0.01 to 1.0 mg/L in the form of potassium iodide or potassium iodate. During the experiments, plant physiological parameters, biomass production, and concentration changes of iodine and selected microelements in different plant parts were investigated. In addition, the oxidation state of the accumulated iodine in root samples was determined. Results showed that iodine addition had no effect on photosynthetic efficiency and chlorophyll content. Iodide treatment did not considerably stimulate biomass production but iodate treatment increased it at concentrations less than 0.5 mg/L. Increasing iodine concentrations in the nutrient solutions increased iodine content in all plant parts; however, the iodide treatment was 2–7 times more efficient than the iodate treatment. It was concluded, that iodide addition was more favourable on the target element accumulation, however, it should be highlighted that application of this chemical form in nutrient solution decreased the concetrations of selected micoelement concentration comparing with the control plants. It was established that iodate was reduced to iodide during its uptake in cabbage roots, which means that independently from the oxidation number of iodine (+ 5, − 1) applied in the nutrient solutions, the reduced form of target element was transported to the aerial and edible tissues.
KW - BAMline
KW - XANES
KW - Synchrotron
KW - Lodine
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608330
DO - https://doi.org/10.1038/s41598-024-66575-z
VL - 14
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-60833
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernal, S. A.
A1 - Dhandapani, Y.
A1 - Elakneswaran, Y.
A1 - Gluth, Gregor
A1 - Gruyaert, E.
A1 - Juenger, M. C. G.
A1 - Lothenbach, B.
A1 - Olonade, K. A.
A1 - Sakoparnig, M.
A1 - Shi, Z.
A1 - Thiel, C.
A1 - Van den Heede, P.
A1 - Vanoutrive, H.
A1 - von Greve-Dierfeld, S.
A1 - De Belie, N.
A1 - Provis, J. L.
T1 - Report of RILEM TC 281-CCC: A critical review of the standardised testing methods to determine carbonation resistance of concrete
N2 - The chemical reaction between CO2 and a blended Portland cement concrete, referred to as carbonation, can lead to reduced performance, particularly when concrete is exposed to elevated levels of CO2 (i.e., accelerated carbonation conditions). When slight changes in concrete mix designs or testing conditions are adopted, conflicting carbonation results are often reported. The RILEM TC 281-CCC ‘Carbonation of Concrete with Supplementary Cementitious Materials’ has conducted a critical analysis of the standardised testing methodologies that are currently applied to determine carbonation resistance of concrete in different regions. There are at least 17 different standards or recommendations being actively used for this purpose, with significant differences in sample curing, pre-conditioning, carbonation exposure conditions, and methods used for determination of carbonation depth after exposure. These differences strongly influence the carbonation depths recorded and the carbonation coefficient values calculated. Considering the importance of accurately determining carbonation potential of concrete, not just for predicting their durability performance, but also for determining the amount of CO2 that concrete can re-absorb during or after its service life, it is imperative to recognise the applicability and limitations of the results obtained from different tests. This will enable researchers and practitioners to adopt the most appropriate testing methodologies to evaluate carbonation resistance, depending on the purpose of the conclusions derived from such testing (e. g. materials selection, service life prediction, CO2 capture potential).
KW - Concrete
KW - Cement
KW - Carbonation
KW - Testing
KW - Standards
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609364
DO - https://doi.org/10.1617/s11527-024-02424-9
VL - 57
SP - 1
EP - 31
PB - Springer Nature
AN - OPUS4-60936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huang, Junhao
A1 - Klahn, Marcus
A1 - Tian, Xinxin
A1 - Bartling, Stephan
A1 - Zimina, Anna
A1 - Radtke, Martin
A1 - Rockstroh, Nils
A1 - Naliwajko, Pawel
A1 - Steinfeldt, Norbert
A1 - Peppel, Tim
A1 - Grunwaldt, Jan‐Dierk
A1 - Logsdail, Andrew J.
A1 - Jiao, Haijun
A1 - Strunk, Jennifer
T1 - Fundamental Structural and Electronic Understanding of Palladium Catalysts on Nitride and Oxide Supports
N2 - The nature of the support can fundamentally affect the function of a heterogeneous catalyst. For the novel type of isolated metal atom catalysts, sometimes referred to as single‐atom catalysts, systematic correlations are still rare. Here, we report a general finding that Pd on nitride supports (non‐metal and metal nitride) features a higher oxidation state compared to that on oxide supports (non‐metal and metal oxide). Through thorough oxidation state investigations by X‐ray absorption spectroscopy (XAS), X‐ray photoelectron spectroscopy (XPS), CO‐DRIFTS, and density functional theory (DFT) coupled with Bader charge analysis, it is found that Pd atoms prefer to interact with surface hydroxyl group to form a Pd(OH)x species on oxide supports, while on nitride supports, Pd atoms incorporate into the surface structure in the form of Pd−N bonds. Moreover, a correlation was built between the formal oxidation state and computational Bader charge, based on the periodic trend in electronegativity.
KW - BAmline
KW - XANES
KW - Catalyst
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608341
DO - https://doi.org/10.1002/anie.202400174
SN - 1433-7851
VL - 63
IS - 20
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-60834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, Ricky
A1 - Sturm, Patrick
A1 - Keßler, S.
A1 - Gluth, Gregor
ED - Lothenbach, B.
ED - Wieland, E.
ED - Altmaier, M.
T1 - Influence of salt aggregate on the degradation of hybrid alkaline cement (HAC) concretes in magnesium chloride-rich saline solution simulating evaporite rock
N2 - Concretes produced from salt aggregate and hybrid alkaline cements, an alkali-activated slag/fly ash blend, or a Portland cement were exposed to a magnesium chloride-rich saline solution ([Mg2+] = 3.6 m, [Cl−] = 8.3 m), representing a solution formed after contact of surface water with evaporite rock (rock salt) in a nuclear waste repository. The hydration and deterioration of the concretes were studied with X-ray diffraction, thermogravimetric analysis, pH mapping and permeability measurements. The results show that calcium silicate hydrate (C-S-H) or sodium-substituted calcium aluminium silicate hydrate (C-N-A-S-H) and Friedel's salt were the major reaction products in the concretes prior to exposure to the saline solution. During exposure to the saline solution, increasing amounts of C-S-H/C-N-A-S-H dissolved, and gypsum and a secondary AFm phase formed. The durability of the concretes improved with increasing amounts of Portland clinker in the cements, due to the associated differences in permeability and chemical resistance. Nevertheless, a massive increase of permeability occurred for all concretes, likely caused by crack formation due to the formation of gypsum from anhydrite in the salt aggregate. Thus, the behavior of the concretes differed from, and was more complex than, the behavior of plain cement pastes.
T2 - Joint 6th International Workshop on Mechanisms and Modelling of Waste/Cement Interactions (JCCW 2023)
CY - Prague, Czech Republic
DA - 20.11.2023
KW - Nuclear waste repository
KW - Evaporite rock
KW - Magnesium chloride brine
KW - Concrete
KW - Hybrid alkaline cement
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599928
DO - https://doi.org/10.1016/j.apgeochem.2024.106027
SN - 0883-2927
SN - 1872-9134
VL - 168
SP - 1
EP - 14
PB - Elsevier
AN - OPUS4-59992
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glazyrin, Konstantin
A1 - Spektor, Kristina
A1 - Bykov, Maxim
A1 - Dong, Weiwei
A1 - Yu, Ji‐Hun Yu
A1 - Yang, Sangsun Yang
A1 - Lee, Jai‐Sung Lee
A1 - Divinski, Sergiy V.
A1 - Hanfland, Michael
A1 - Yusenko, Kirill
T1 - High‐Entropy Alloys and Their Affinity with Hydrogen: From Cantor to Platinum Group Elements Alloys
N2 - AbstractProperties of high‐entropy alloys are currently in the spotlight due to their promising applications. One of the least investigated aspects is the affinity of these alloys to hydrogen, its diffusion, and reactions. In this study, high pressure is applied at ambient temperature and stress‐induced diffusion of hydrogen is investigated into the structure of high‐entropy alloys (HEA) including the famous Cantor alloy as well as less known, but nevertheless important platinum group (PGM) alloys. By applying X‐ray diffraction to samples loaded into diamond anvil cells, a comparative investigation of transition element incorporating HEA alloys in Ne and H2 pressure‐transmitting media is performed at ambient temperature. Even under stresses far exceeding conventional industrial processes, both Cantor and PGM alloys show exceptional resistance to hydride formation, on par with widely used industrial grade Cu–Be alloys. The observations inspire optimism for practical HEA applications in hydrogen‐relevant industry and technology (e.g., coatings, etc), particularly those related to transport and storage.
KW - XRD
KW - HIgh entropy,
KW - Cantor
KW - Alloys
KW - Synchrotron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604170
DO - https://doi.org/10.1002/advs.202401741
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-60417
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hajhariri, Aliasghar
A1 - Eberwein, Robert
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Cozzani, Valerio
A1 - Otremba, Frank
A1 - Seidlitz, Holger
T1 - Non-combustible MLI based insulation behavior under fire condition - Experimental and numerical investigation
N2 - The number of applications that demand zero-emission energy carriers, such as liquified hydrogen (LH2), is increasing worldwide. LH2 is typically transported or stored under cryogenic conditions. Storage in such conditions requires super thermal insulations which maintain very low boil-off for a prolonged time. Multi-Layer insulation (MLI) finds widespread use in cryogenic applications, designed to effectively restrict heat inleak towards cryogenic fluids. However, recent studies evidenced that exposure to high heat fluxes, such as in the event of a fire accident, can cause the thermal degradation of the insulation material, resulting in the severe collapse of its heat resistance performance. Therefore, the risk of rapid tank pressurization and its connection to the risk of BLEVE may be possible. This study proposes a numerical model to assess the performances of aluminum-based MLI materials under fire conditions. The model offers insights into the total heat transfer rate through the insulation, serving as a
KW - Multi-Layer Insulation
KW - Cryogenic
KW - Liquid Hydrogen
KW - CFD
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617780
DO - https://doi.org/10.1016/j.psep.2024.11.037
VL - 193
SP - 603
EP - 620
PB - Elsevier B.V.
AN - OPUS4-61778
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Eberwein, Robert
A1 - Hajhariri, Aliasghar
A1 - Otremba, Frank
A1 - Cozzani, Valerio
T1 - Comparative performance assessment of multilayer insulation (MLI) systems for liquid hydrogen vessels in fire scenarios
N2 - Multilayer Insulation (MLI) systems are a mature technology for cryogenic liquid hydrogen (LH2) tank thermal insulation. Recent tests evidenced that MLI materials may be damaged when exposed to fire, resulting in critical safety issues in the case of accidents. Thus, an innovative approach to the performance assessment of aluminum and polyester-based MLIs for LH2 tanks in fire scenarios was developed. A specific model integrating the hightemperature degradation of MLIs and the thermodynamic modeling of the tank lading was coupled to specific key performance indicators. Results of the analysis applied to a vehicle-scale tank equipped with 80 MLI layers indicate that MLI degradation and consequent tank failure may occur in less than 20 min for external shell temperatures above 1160 K in the presence of full engulfment, regardless of insulation used. Conversely, degradation does not occur earlier than 3600s below 603 and 928 K for polyester and aluminum-based MLI, respectively.
KW - LH2
KW - LNG
KW - Cryogenic storage tank
KW - Fire
KW - Insulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630841
DO - https://doi.org/10.1016/j.ijhydene.2025.04.534
SN - 0360-3199
VL - 135
SP - 537
EP - 552
PB - Elsevier Ltd.
AN - OPUS4-63084
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Denora, Isabella
A1 - Clute, Clara
A1 - Murillo, Natalia Cano
A1 - Theiler, Geraldine
A1 - Balasooriya, Winoj
A1 - Kaiser, Andreas
A1 - Fasching, Michael
A1 - Schwarz, Thomas
A1 - Marano, Claudia
T1 - A study on the mechanical behaviour of carbon black and Struktosil-filled NBR compounds for hydrogen applications
N2 - This study investigates the effect of the addition of a 2D filler (Struktosil) to a carbon black-filled acrylonitrile butadiene rubber, developed for seals in hydrogen applications. Several characterization methods have been adopted. The addition of Struktosil increases the stiffness of the material up to a strain of about 100%, to a lesser extent in presence of a plasticizer. The dissipative response of the material is increased by Struktosil addition and decreased in presence of the plasticizer. Concerning fracture behaviour, the crack initiation and Rapid Gas Decompression (RGD) resistance were not affected by the addition of Struktosil but decreased in presence of plasticizer. Furthermore, the addition of Struktosil had a positive effect on crack propagation resistance. The effects of pressurized hydrogen exposure on physical-mechanical properties were also evaluated and correlated with the results. A correlation between fracture toughness and RGD resistance has been also attempted.
KW - Acrylonitrile Butadiene rubber
KW - Fracture mechanics
KW - 2D filler
KW - High-pressure hydrogen
KW - Rapid gas decompression
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648285
DO - https://doi.org/10.1016/j.ijhydene.2025.03.122
SN - 0360-3199
VL - 118
SP - 407
EP - 416
PB - Elsevier Ltd.
AN - OPUS4-64828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sarif, Raduan
A1 - Tiebe, Carlo
A1 - Herglotz, Christian
T1 - Early Response Prediction for H2 Sensors
N2 - Green hydrogen (H2) is essential for the global transition to clean energy; it will significantly reduce emissions from heavy industry and the long-distance transport system. H2 can be used as fuel in fuel cells, storing surplus renewable energy, and as a feedstock in industrial processes. However, H2 faces significant safety challenges during storage and transportation. Accidents due to H2 leakage and explosions raise serious concerns due to its high flammability, rapid diffusion in air, and extremely low ignition energy. To mitigate risks associated with H2 leakages, reliable and automated H2 safety systems are essential for emergency repairs or shutdown. An early response from H2 sensors is crucial for early warning in accidents. The earlier response time of H2 sensors is often constrained by their sensor principle, which is heavily influenced by the sensor material’s properties. This study explores methods for earlier sensor response through predictive algorithms. Specifically, we investigate transient response predictions using a First-Order (FO) model and propose improvements through the First-Order with early response and the First-Order with adapted early response model. Both models can predict the stable value of the H2 sensor response from a small time window, which is 70.89% and 83.72% earlier, respectively, than the time required for the sensor hardware to reach it physically. The model’s performance is evaluated by calculating the fitting error with a 2 % threshold. Our current research lays the groundwork for future advancements in real-time sensor response predictions for hydrogen leakage.
T2 - IARIA Congress 2025 : The 2025 IARIA Annual Congress on Frontiers in Science, Technology, Services, and Applications
CY - Venice, Italy
DA - 06.07.2025
KW - H2 Safety
KW - H2 leakage detection
KW - First-Order (FO) model
KW - H2 Sensor data analysis
KW - H2 sensor response predictions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640676
UR - https://www.thinkmind.org/articles/iaria_congress_2025_1_250_50159.pdf
SN - 978-1-68558-284-5
SP - 1
EP - 8
PB - IARIA Press
CY - Wilmington
AN - OPUS4-64067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sarif, Raduan
A1 - Tiebe, Carlo
A1 - Herglotz, Christian
T1 - Analysis of Methods for Predicting H2 Sensor Responses
N2 - Hydrogen (H2) is crucial for replacing fossil fuels and achieving net-zero emissions, but its flammability and explosiveness pose safety challenges. Rapid H2 leak detection is essential for triggering emergency accidents. However, H2 sensor response is constrained by material properties and gas flow dynamics, causing response and detection delays. Our current study explores various available algorithms for H2 sensor response prediction from early responses with a small time window, accelerating leakage detection. Our findings identify the most efficient algorithms for real-time implementation, enhancing H2 safety systems.
T2 - SMSI 2025 2025-05-06 - 2025-05-08 Nürnberg
CY - Nuremberg, Germany
DA - 06.05.2025
KW - H2 safety
KW - Early H2 leakage detection
KW - Prediction algorithms
KW - Stable H2 value prediction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640617
SN - 978-3-910600-06-5
DO - https://doi.org/10.5162/SMSI2025/C6.3
SP - 169
EP - 170
PB - AMA Verband für Sensorik und Messtechnik e.V.
CY - Berlin
AN - OPUS4-64061
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grengg, C.
A1 - Gluth, Gregor
A1 - Mittermayr, F.
A1 - Ukrainczyk, N.
A1 - Bertmer, M.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Leis, A.
A1 - Dietzel, M.
T1 - Deterioration mechanism of alkali-activated materials in sulfuric acid and the influence of Cu: A micro-to-nano structural, elemental and stable isotopic multi-proxy study
N2 - In this study, a multi-proxy approach combining 29Si, 27Al and 1H MAS-NMR, FEG-EPMA, XANES at the Cu K-edge and XRD analytics with hydrochemical tools such as ICP-OES analyses, oxygen-isotope signatures, and thermodynamic modelling was applied to K-silicate-activated metakaolin specimens - with and without CuSO4·5H2O addition - exposed to sulfuric acid at pH = 2 for 35 days. The results revealed a multistage deterioration mechanism governed by (i) acid diffusion, (ii) leaching of K-A-S-H, (iii) microstructural damage related to precipitation of expansive (K,Ca,Al)-sulfate-hydrate phases (iv) complete dissolution of the K-A-S-H framework, (v) and formation of silica gel in the outermost corroded regions. Copper ions were mainly located in layered spertiniite-chrysocolla-like phases in the as-cured materials. The results demonstrate an overall negative effect of Cu addition on chemical material durability, implying that the reported higher durability of Cu-doped AAM in biocorrosion environments can be best explained by bacteriostatic effects.
KW - Alkali-activated materials
KW - Acid resistance
KW - Microbially induced corrosion
KW - MIC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520567
DO - https://doi.org/10.1016/j.cemconres.2021.106373
SN - 0008-8846
VL - 142
SP - 1
EP - 15
PB - Elsevier
CY - Oxford
AN - OPUS4-52056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radtke, Martin
A1 - Buzanich, Günter
A1 - Curado, Jessica
A1 - Reinholz, Uwe
A1 - Riesemeier, Heinrich
A1 - Scharf, O.
T1 - Slicing - a new method for non destructive 3D elemental sensitive characterization of materials
N2 - Recent advances in synchrotron sources and detector technology have led to substantial improvements in spatial resolution and detection limits for X-ray fluorescence analysis (XRF). However, the non-destructive three-dimensional elemental sensitive characterization of samples remains a challenge. We demonstrate the use of the so-called 'Color X-ray Camera' (CXC) for 3D measurements for the first time. The excitation of the sample is realized with a thin sheet-beam. The stepwise movement of the sample allows getting the elemental distribution for each layer with one measurement. These layers can be combined to a full 3D dataset for each element afterwards. Since the information is collected layer by layer, there is no need to apply reconstruction techniques, which quite often are the reason for artifacts in the results achieved by computed tomography (CT). The field of applications is wide, as the 3D elemental distribution of a material contains clues to processes inside the samples from a variety of origins. The technique is of special interest and well suited for biological specimens, because their light matrix minimizes restricting absorption effects. Measurement examples of a hornet and the teeth of a Sorex araneus are shown.
KW - SR-microXRF
KW - 3D
KW - CXC
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-324330
DO - https://doi.org/10.1039/c4ja00085d
SN - 0267-9477
SN - 1364-5544
VL - 29
IS - 8
SP - 1339
EP - 1344
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-32433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Chen, K.
A1 - Radu, F.
A1 - Weschke, E.
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
T1 - Al-driven peculiarities of local coordination and magnetic properties in single-phase Alx-CrFeCoNi high-entropy alloys
N2 - Modern design of superior multi-functional alloys composed of several principal components requires in-depth studies of their local structure for developing desired macroscopic properties. Herein, peculiarities of atomic arrangements on the local scale and electronic states of constituent elements in the single-phase face-centered cubic (fcc)- and body-centered cubic (bcc)-structured high-entropy Alx-CrFeCoNi alloys (x = 0.3 and 3, respectively) are explored by element-specific X-ray absorption spectroscopy in hard and soft X-ray energy ranges. Simulations based on the reverse Monte Carlo approach allow to perform a simultaneous fit of extended X-ray absorption fine structure spectra recorded at K absorption edges of each 3d constituent and to reconstruct the local environment within the first coordination shells of absorbers with high precision. The revealed unimodal and bimodal distributions of all five elements are in agreement with structure-dependent magnetic properties of studied alloys probed by magnetometry. A degree of surface atoms oxidation uncovered by soft X-rays suggests different kinetics of oxide formation for each type of constituents and has to be taken into account. X-ray magnetic circular dichroism technique employed at L2,3 absorption edges of transition metals demonstrates reduced magnetic moments of 3d metal constituents in the sub-Surface region of in situ cleaned fcc-structured Al0.3-CrFeCoNi compared to their bulk values. Extended to nanostructured versions of multicomponent alloys, such studies would bring new insights related to effects of high entropy mixing on low dimensions.
KW - X-ray magnetic circular dichroism (XMCD)
KW - High-entropy alloys
KW - Reverse Monte Carlo
KW - Magnetism
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530668
DO - https://doi.org/10.1007/s12274-021-3704-5
SN - 1998-0124
VL - 15
IS - 6
SP - 4845
EP - 4858
PB - Springer
AN - OPUS4-53066
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lutz, C.
A1 - Breuckmann, M.
A1 - Hampel, S.
A1 - Kreyenschmidt, M.
A1 - Ke, X.
A1 - Beuermann, S.
A1 - Schafner, K.
A1 - Turek, T.
A1 - Kunz, U.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Fittschen, U. E. A.
T1 - Characterization of Dimeric Vanadium Uptake and Species in Nafion™ and Novel Membranes from Vanadium Redox Flow Batteries Electrolytes
N2 - A core component of energy storage systems like vanadium redox flow batteries (VRFB) is the polymer electrolyte membrane (PEM). In this work, the frequently used perfluorosulfonic-acid (PFSA) membrane Nafion™ 117 and a novel poly (vinylidene difluoride) (PVDF)-based Membrane are investigated. A well-known problem in VRFBs is the vanadium permeation through the membrane. The consequence of this so-called vanadium crossover is a severe loss of capacity. For a
better understanding of vanadium transport in membranes, the uptake of vanadium ions from electrolytes containing Vdimer(IV–V) and for comparison also V(II), V(III), V(IV), and V(V) by both membranes was studied. UV/VIS spectroscopy, X-ray absorption near edge structure spectroscopy (XANES), total reflection X-ray fluorescence spectroscopy (TXRF), inductively coupled plasma optical emission spectrometry (ICP-OES), and micro X-ray fluorescence spectroscopy (microXRF) were used to determine the vanadium concentrations and the species inside the membrane. The results strongly support that Vdimer(IV–V), a dimer formed from V(IV) and V(V), enters the nanoscopic water-body of Nafion™ 117 as such. This is interesting, because as of now, only the individual ions V(IV) and V(V) were considered to be transported through the membrane. Additionally, it was found that the Vdimer(IV–V) dimer partly dissociates to the individual ions in the novel PVDF-based membrane.
The Vdimer(IV–V) dimer concentration in Nafion™ was determined and compared to those of the other species. After three days of equilibration time, the concentration of the dimer is the lowest compared to the monomeric vanadium species. The concentration of vanadium in terms of the relative uptake λ = n(V)/n(SO3
) are as follows: V(II) [λ = 0.155] > V(III) [λ = 0.137] > V(IV) [λ = 0.124] > V(V) [λ = 0.053] > Vdimer(IV–V) [λ = 0.039]. The results show that the Vdimer(IV–V) dimer Needs to be considered in addition to the other monomeric species to properly describe the transport of vanadium through Nafion™ in VRFBs.
KW - MicroXRF
KW - VRFB
KW - PVDF-based membrane
KW - UV/VIS
KW - XANES
KW - TXRF
KW - ICP-OES
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530676
DO - https://doi.org/10.3390/membranes11080576
VL - 11
IS - 8
SP - 576
PB - MDPI
AN - OPUS4-53067
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Vogl, Jochen
A1 - Gluth, Gregor
A1 - Stephan, D.
T1 - Provenancing of cement using elemental analyses and isotope techniques – The state-of-the-art and future perspectives
N2 - With the aim of identifying the origin and the manufacturer of a cement, a reliable procedure that provides unambiguous results is needed. Such procedure could resolve practical issues in damage research, liability issues and forensic investigations. A substantial number of attempts for fingerprinting of building materials, including cement, has already been carried out during the last decades. Most of them were based on concentration analysis of the main elements/components. This review provides an overview of provenance studies of cement and the main approaches commonly used. Provenance studies of cement via isotope techniques are also presented and discussed as representatives of the state-of-the-art in the field. Due to the characteristic properties and the occurrence of carefully selected isotope ratios, unique fingerprints of different kinds of materials can be provided by these methods. This property has largely been explored in various scientific fields such as geo- and cosmochemistry, food forensics, archaeology, geochronology, biomedical studies, and climate change processes. However, the potential of isotope techniques in cement and concrete research for provenance studies has barely been investigated.
Therefore, the review outlines a suitable approach using isotope ratios, which could lead to reliable provenancing of cementitious materials in the future.
KW - Cement
KW - Sr isotopes
KW - Provenance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533762
DO - https://doi.org/10.1039/d1ja00144b
VL - 36
IS - 10
SP - 2030
EP - 2042
PB - The Royal Society of Chemistry
CY - Cambridge, UK
AN - OPUS4-53376
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Recent developments of X-ray absorption spectroscopy as analytical tool for biological and biomedical applications
N2 - X-ray absorption spectroscopy (XAS), in its various modalities, has gained exponential attention and applicability in the field of biological and biomedical systems. Particularly in this field, challenges like low concentration of analyte or proneness to radiation damage have certainly settle the basis for further analytical developments, when using X-ray based methods. Low concentration calls for higher sensitivity—by increasing the detection limits (DL); while susceptibility for radiation damage requires shorter measurement times and/or cryogenic sample environment possibilities. This manuscript reviews the latest analytical possibilities that make XAS more and more adequate to investigate biological or biomedical systems in the last 5 years.
KW - Biological & biomedical applications
KW - TXRF-XAS
KW - HERFD-XAS
KW - RXES
KW - Quick-XAS
KW - Dispersive-XAS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531206
DO - https://doi.org/10.1002/xrs.3254
SN - 0049-8246
VL - 51
IS - 3
SP - 1
EP - 10
PB - John Wiley & Sons Ltd
AN - OPUS4-53120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Guerra, M.F.
A1 - Martinón-Torres, M.
A1 - Lemasson, Q.
A1 - Moignard, B.
A1 - Pacheco, C.
A1 - Pichon, L.
A1 - Macdonald, L.
A1 - Hess, M.
A1 - Tissot, I.
ED - Guerra, M. F.
ED - Martinón-Torres, M.
ED - Quirke, S.
T1 - Analytical approaches to Egyptian goldwork
N2 - The structure and composition of ancient gold objects retain information about their long history of manufacture, from the exploitation of the ore to the finishing touches, as well as evidence of their use, deposition, and degradation. By developing an efficient analytical strategy, it is possible to retrieve that information. This chapter sets the necessary foundation 131to explore fully the analytical results presented in the following chapters of this volume. The techniques employed in the analyses of the Egyptian jewellery are described and the analytical parameters provided. For more established techniques, only brief introductions are presented, while more recent developments are presented in greater detail.
KW - Gold
KW - Synchrotron
KW - D2XRF
KW - Egypt
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586039
DO - https://doi.org/10.17863/CAM.99681
SP - 131
EP - 191
AN - OPUS4-58603
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Bartling, Stephan
A1 - Parlinska-Wojtan, Magdalena
A1 - Wotzka, Alexander
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, Sebastian
A1 - Abdel-Mageed, Ali M.
T1 - Stabilization of intermediate Mo oxidation states by Nb doping enhancing methane aromatization on Mo/HZSM-5 catalysts
N2 - The dehydroaromatization of methane is a promising process to produce aromatics and ultra-pure hydrogen. Increased yields and stability of Mo/HZSM-5 against irreversible deactivation were achieved via a redox interaction by doping with otherwise inert Nb.
KW - General Materials Science
KW - Sustainability and the Environment
KW - General Chemistry
KW - Renewable Energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597670
DO - https://doi.org/10.1039/D3TA07532J
SN - 2050-7488
SP - 1
EP - 16
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59767
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, Alevtina
A1 - Gaertner, Daniel
A1 - Kuzmin, Alexei
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Schuck, Goetz
A1 - Zizak, Ivo
A1 - Wilde, Gerhard
A1 - Yusenko, Kirill
A1 - Divinski, Sergiy
T1 - Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi high-entropy alloy
N2 - AbstractMulti-edge extended X-ray absorption fine structure (EXAFS) spectroscopy combined with reverse Monte Carlo (RMC) simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing temperature. Two representative states, namely a high-temperature state, created by annealing at 1373 K, and a low-temperature state, produced by long-term annealing at 993 K, were compared in detail. Specific features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative temperatures. The detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.
KW - Electrical and Electronic Engineering
KW - General Materials Science
KW - Condensed Matter Physics
KW - Atomic and Molecular Physics, and Optics
KW - CCMat
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597687
DO - https://doi.org/10.1007/s12274-024-6443-6
SN - 1998-0124
VL - 17
IS - 6
SP - 5336
EP - 5348
PB - Springer Science and Business Media LLC
AN - OPUS4-59768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Mundra, Shishir
A1 - Henning, Ricky
T1 - Chloride binding by layered double hydroxides (LDH/AFm phases) and alkali-activated slag pastes: an experimental study by RILEM TC 283-CAM
N2 - Chloride binding by the hydrate phases of cementitious materials influences the rate of chloride ingress into these materials and, thus, the time at which chloride reaches the steel reinforcement in concrete structures. Chloride binding isotherms of individual hydrate phases would be required to model chloride ingress but are only scarcely available and partly conflicting. The present study by RILEM TC 283-CAM ‘Chloride transport in alkali-activated materials’ significantly extends the available database and resolves some of the apparent contradictions by determining the chloride binding isotherms of layered double hydroxides (LDH), including AFm phases (monosulfate, strätlingite, hydrotalcite, and meixnerite), and of alkali-activated slags (AAS) produced with four different activators (Na2SiO3, Na2O·1.87SiO2, Na2CO3, and Na2SO4), in NaOH/NaCl solutions at various liquid/solid ratios. Selected solids after chloride binding were analysed by X-ray diffraction, and thermodynamic modelling was applied to simulate the phase changes occurring during chloride binding by the AFm phases. The results of the present study show that the chloride binding isotherms of LDH/AFm phases depend strongly on the liquid/solid ratio during the experiments. This is attributed to kinetic restrictions, which are, however, currently poorly understood. Chloride binding by AAS pastes is only moderately influenced by the employed activator. A steep increase of the chloride binding by AAS occurs at free chloride concentrations above approx. 1.0 M, which is possibly related to chloride binding by the C–(N–)A–S–H gel in the AAS.
KW - Chloride binding
KW - Sorption isotherm
KW - Layered double hydroxide
KW - AFm phase
KW - Alkali-activated materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599370
DO - https://doi.org/10.1617/s11527-024-02311-3
SN - 1359-5997
SN - 1871-6873
VL - 57
IS - 4
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-59937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Licht, M.
A1 - Nikoonasab, Ali
A1 - Gluth, Gregor
A1 - Raupach, M.
ED - Claßen, M.
ED - Hegger, J.
ED - Matschei, T.
ED - Raupach, M.
T1 - Alkali-aktivierte Hüttensandbetone – CO2-reduzierte Bindemittel mit hohem Korrosionsschutzpotential
N2 - Durch den Ersatz von Portlandzement können alkali-aktivierte Bindemittel einen bedeutenden Beitrag zur Verringerung der durch die Zementklinkerherstellung verursachten CO2-Emissionen leisten. Für die Verwendung von alkali-aktivierten Bindemitteln in Stahlbetonkonstruktionen, die Chloriden oder Carbonatisierung ausgesetzt sind, ist die Fähigkeit des Stahls, den passiven Zustand zu erreichen und aufrechtzuerhalten, von großer Bedeutung. Die Prozesse der Deckschichtbildung von Stahl in alkali-aktivierten Materialien unterscheiden sich jedoch zum Teil grundlegend von denen in Portlandzementen. Alkali-aktivierte Hüttensandbetone weisen gute technische Eigenschaften auf, bisher fehlen jedoch grundlegende Kenntnisse bzgl. ihrer schützenden Wirkung bei korrosiven Angriffen. Dies ist vor allem auf ihre sulfidhaltige Porenlösung zurückzuführen, welche die elektrochemischen Eigenschaften der Stahloberfläche beeinflusst und die Verwendung herkömmlicher Bewertungsmaßstäbe erschwert. Es werden erste Ergebnisse eines DFG-Forschungsprojektes vorgestellt, in dem das Passivierungsverhalten von Stahl in alkali-aktivierten Hüttensandmörteln unterschiedlicher Zusammensetzungen sowie in Mörteln auf Basis hüttensandhaltiger Normzemente untersucht wird. Über einen Zeitraum von mindestens 28 Tagen werden an Zylinderprüfkörpern im 3-Elektroden-Aufbau das Ruhepotential sowie die Polarisationswiderstände der Stahlelektroden ermittelt.
T2 - 10. DAfStb-Jahrestagung mit 62. Forschungskolloquium
CY - Aachen, Germany
DA - 26.09.2023
KW - Bewehrung
KW - Stahlkorrosion
KW - Hüttensandmehl
KW - Sulfid
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593775
DO - https://doi.org/10.18154/RWTH-2023-06676
SP - 233
EP - 238
PB - RWTH Aachen
CY - Aachen
AN - OPUS4-59377
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - C. Pardo Pérez, L.
A1 - Arndt, A.
A1 - Stojkovikj, S.
A1 - Y. Ahmet, I.
A1 - T. Arens,, J.
A1 - Dattila, F.
A1 - Wendt, R.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Davies, V.
A1 - Höflich, K.
A1 - Köhnen, E.
A1 - Tockhorn, P.
A1 - Golnak, R.
A1 - Xiao, J.
A1 - Schuck, G.
A1 - Wollgarten, M.
A1 - López, N.
A1 - T. Mayer, M.
T1 - Determining Structure-Activity Relationships in Oxide Derived CuSn Catalysts During CO2 Electroreduction Using X-Ray Spectroscopy
N2 - The development of earth-abundant catalysts for selective electrochemical CO2 conversion is a central challenge. Cu-Sn bimetallic catalysts can yield selective CO2 reduction toward either CO or formate. This study presents oxide-derived Cu-Sn catalysts tunable for either product and seeks to understand the synergetic effects between Cu and Sn causing these selectivity trends. The materials undergo significant transformations under CO2 reduction conditions, and their dynamic bulk and surface structures are revealed by correlating observations from multiple methods—X-ray absorption spectroscopy for in situ study, and quasi in situ X-ray photoelectron spectroscopy for surface sensitivity. For both types of catalysts, Cu transforms to metallic Cu0 under reaction conditions. However, the Sn speciation and content differ significantly between the catalyst types: the CO-selective catalysts exhibit a surface Sn content of 13 at. % predominantly present as oxidized Sn, while the formate-selective catalysts display an Sn content of ≈70 at. % consisting of both metallic Sn0 and Sn oxide species. Density functional theory simulations suggest that Snδ+ sites weaken CO adsorption, thereby enhancing CO selectivity, while Sn0 sites hinder H adsorption and promote formate production. This study reveals the complex dependence of catalyst structure, composition, and speciation with electrochemical bias in bimetallic Cu catalysts.
KW - Electrochemical CO2 conversion
KW - Cu catalysts
KW - X-ray absorption spectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547116
DO - https://doi.org/10.1002/aenm.202103328
SN - 1614-6832
VL - 12
IS - 5
SP - 2103328
PB - Wiley-VCH GmbH
AN - OPUS4-54711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kunkel, B.
A1 - Kabelitz, Anke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wohlrab, S.
T1 - Increasing the Efficiency of Optimized V-SBA-15 Catalysts in the Selective Oxidation of Methane to Formaldehyde by Artificial Neural Network Modelling
N2 - The present study investigates the possibility of improving the selective oxidation of methane to formaldehyde over V-SBA-15 catalysts in two different ways. In a classical approach of catalyst optimization, the in situ synthesis of V-SBA-15 catalysts was optimized with regard to the applied pH value. Among the set of catalysts synthesized, a higher amount of incorporated vanadium, a higher content of polymeric VOx species as well as a less ordered structure of the support material were observed by increasing the pH values from 2.0 to 3.0. An optimum in performance during the selective oxidation of methane to formaldehyde with respect to activity and selectivity was found over V-SBA-15 prepared at a pH value of 2.5. With this knowledge, we have now evaluated the possibilities of reaction control using this catalyst. Specifically, artificial neural network modelling was applied after the collection of 232 training samples for obtaining insight into the influence of different reaction parameters (temperature; gas hourly space velocity (GHSV); and concentration of O2, N2 and H2O) onto methane conversion and selectivity towards formaldehyde.
This optimization of reaction conditions resulted in an outstanding high space-time yield of 13.6 kgCH2O∙kgcat∙h−1
KW - Artificial neural network modelling
KW - Selective oxidation
KW - Molecular VOx catalysts
KW - Formaldehyde
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517420
DO - https://doi.org/10.3390/catal10121411
VL - 10
IS - 12
SP - 1411
PB - MDPI
AN - OPUS4-51742
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winnefeld, F.
A1 - Gluth, Gregor
A1 - Bernal, S. A.
A1 - Bignozzi, M. C.
A1 - Carabba, L.
A1 - Chithiraputhiran, S.
A1 - Dehghan, A.
A1 - Dolenec, S.
A1 - Dombrowski-Daube, K.
A1 - Dubey, A.
A1 - Ducman, V.
A1 - Yu, J.
A1 - Peterson, K.
A1 - Stephan, D.
A1 - Provis, J. L.
T1 - RILEM TC 247-DTA round robin test: sulfate resistance, alkali-silica reaction and freeze–thaw resistance of alkali-activated concretes
N2 - The RILEM technical committee TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ conducted a round robin testing programme to determine the validity of various durability testing methods, originally developed for Portland cement based-concretes, for the assessment of the durability of alkali-activated concretes. The outcomes of the round robin tests evaluating sulfate resistance, alkali-silica reaction (ASR) and freeze–thaw resistance are presented in this contribution. Five different alkali-activated concretes, based on ground granulated blast furnace slag, fly ash, or metakaolin were investigated. The extent of sulfate damage to concretes based on slag or fly ash seems to be limited when exposed to an Na2SO4 solution. The mixture based on metakaolin showed an excessive, very early expansion, followed by a dimensionally stable period, which cannot be explained at present. In the slag-based concretes, MgSO4 caused more expansion and visual damage than Na2SO4; however, the expansion limits defined in the respective standards were not exceeded. Both the ASTM C1293 and RILEM AAR-3.1 test methods for the determination of ASR expansion appear to give essentially reliable identification of expansion caused by highly reactive aggregates. Alkali-activated materials in combination with an unreactive or potentially expansive aggregate were in no case seen to cause larger expansions; only the aggregates of known very high reactivity were seen to be problematic. The results of freeze–thaw testing (with/without deicing salts) of alkali-activated concretes suggest an important influence of the curing conditions and experimental conditions on the test outcomes, which need to be understood before the tests can be reliably applied and interpreted.
KW - Alkali-activated materials
KW - Sulfate attack
KW - Alkali silica reaction
KW - Alkali aggregate reaction
KW - Freeze-thaw attack
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515527
DO - https://doi.org/10.1617/s11527-020-01562-0
VL - 53
IS - 6
SP - 140
PB - Springer Nature
AN - OPUS4-51552
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mundra, Shishir
A1 - Provis, J. L.
T1 - Mechanisms of passivation and chloride-induced corrosion of mild steel in sulfide-containing alkaline solutions
N2 - The pore fluid within many concretes is highly alkaline and rich in reduced sulfur species, but the influence of such alkaline-sulfide solutions on the surface film formed on steel reinforcement is poorly understood. This study investigates the critical role of HS− in defining mild steel passivation chemistry. The surface film formed on the steel in alkaline-sulfide solutions contains Fe(OH)2 and Fe–S complexes, and the critical chloride concentration to induce corrosion increases at high sulfide concentration. However, this behavior is dependent on the duration of exposure of the steel to the electrolyte, and the nature of the sulfidic surface layer.
KW - Alkali-activated materials
KW - Steel corrosion
KW - Sulfide
KW - Chloride
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528861
DO - https://doi.org/10.1007/s10853-021-06237-x
VL - 56
IS - 26
SP - 14783
EP - 14802
PB - Springer Nature
AN - OPUS4-52886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Arbi, K.
A1 - Bernal, S. A.
A1 - Bondar, D.
A1 - Castel, A.
A1 - Chithiraputhiran, S.
A1 - Dehghan, A.
A1 - Dombrowski-Daube, K.
A1 - Dubey, A.
A1 - Ducman, V.
A1 - Peterson, K.
A1 - Pipilikaki, P.
A1 - Valcke, S. L. A.
A1 - Ye, G.
A1 - Zuo, Y.
A1 - Provis, J. L.
T1 - RILEM TC 247-DTA round robin test: carbonation and chloride penetration testing of alkali-activated concretes
N2 - Many standardised durability testing methods have been developed for Portland cement-based concretes, but require validation to determine whether they are also applicable to alkali-activated materials. To address this question, RILEM TC 247-DTA ‘Durability Testing of Alkali-Activated Materials’ carried out round robin testing of carbonation and chloride penetration test methods, applied to five different alkali-activated concretes based on fly ash, blast furnace slag or metakaolin. The methods appeared overall to demonstrate an intrinsic precision comparable to their precision when applied to conventional concretes. The ranking of test outcomes for pairs of concretes of similar binder chemistry was satisfactory, but rankings were not always reliable when comparing alkali-activated concretes based on different precursors. Accelerated carbonation testing gave similar results for fly ash-based and blast furnace slag-based alkali-activated concretes, whereas natural carbonation testing did not. Carbonation of concrete specimens was observed to have occurred already during curing, which has implications for extrapolation of carbonation testing results to longer service life periods. Accelerated chloride penetration testing according to NT BUILD 443 ranked the tested concretes consistently, while this was not the case for the rapid chloride migration test. Both of these chloride penetration testing methods exhibited comparatively low precision when applied to blast furnace slag-based concretes which are more resistant to chloride ingress than the other materials tested.
KW - Alkali-activated materials
KW - Durability
KW - Carbonation
KW - Chloride penetration
KW - Concrete
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504045
DO - https://doi.org/10.1617/s11527-020-1449-3
SN - 1359-5997
SN - 1871-6873
VL - 53
IS - 1
SP - 21
PB - Springer Nature
AN - OPUS4-50404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Simon, Sebastian
A1 - Gluth, Gregor
ED - Rossignol, S.
ED - Gluth, Gregor
T1 - Unraveling the hardening mechanism during laser-induced slip casting of lithium aluminate-microsilica slurry
N2 - Additive manufacturing (AM) of alkali-activated materials is a promising method for producing ceramic precursors, construction elements and other parts. A recently introduced AM process is laser-induced slip casting of lithium aluminate/microsilica slurries, which yields parts with excellent mechanical strengths. To clarify the underlying mechanisms, μ-Raman spectroscopy was applied to parts produced by the process, and the dissolution and hydration of lithium aluminate was studied inter alia using conventional and in-situ X-ray diffraction. The results show that significant dissolution of lithium aluminate occurs, particularly at increased temperatures during laser interaction, which leads to an increase of pH and precipitation of an akopovaite-like Li-Al-CO3 layered double hydroxide. The increase of the pH is likely to induce dissolution of the microsilica and possibly formation of a hydrous lithium aluminosilicate gel. These observations explain the strength evolution of the studied parts and can also aid the development and improvement of related AM methods.
KW - Alkali-activated materials
KW - Additive manufacturing
KW - Laser-induced slip casting
KW - Lithium
KW - Layered double hydroxide
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520557
DO - https://doi.org/10.1016/j.oceram.2021.100060
SN - 2666-5395
VL - 5
IS - Special issue: Alkali-activated materials and geopolymers in ceramics and beyond
SP - 1
EP - 7
PB - Elsevier
CY - Amsterdam
AN - OPUS4-52055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sturm, Patrick
A1 - Moye, J.
A1 - Gluth, Gregor
A1 - Vogler, Nico
A1 - Taffe, A.
A1 - Kühne, Hans-Carsten
ED - Rossignol, S.
ED - Gluth, Gregor
T1 - Properties of alkali-activated mortars with salt aggregate for sealing structures in evaporite rock
N2 - Concrete structures for sealing of tunnels in the host rock are an essential part of systems for nuclear waste storage. However, concretes based on blended cements or magnesium oxychloride cements, which are commonly considered for this application, can deteriorate severely due to a significant heat of hydration and associated deformation and cracking. Alkali-activated materials (AAMs) offer a potential solution to this problem because of their low heat release during hardening. To explore their suitability for the construction of sealing structures in evaporite rock, various AAMs with salt aggregate were studied regarding fresh properties, heat release, mechanical properties and microstructure. The heat of reaction of the AAMs was up to 55% lower than that of a blended cement designed for sealing structures, indicating significant benefits for the intended application. Other relevant properties such as mechanical strength and permeability depended strongly on the mix-design of the AAMs and curing conditions.
KW - Alkali-activated materials
KW - Geopolymers
KW - Nuclear waste storage
KW - Sealing structures
KW - Evaporite rock
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519422
DO - https://doi.org/10.1016/j.oceram.2020.100041
SN - 2666-5395
VL - 5
IS - Special issue: Alkali-activated materials and geopolymers in ceramics and beyond
SP - 1
EP - 8
PB - Elsevier
CY - Amsterdam
AN - OPUS4-51942
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radtke, Martin
A1 - Rakotondrajoa, A.
T1 - Machine learning based quantification of synchrotron radiation-induced X-ray fluorescence measurements - a case study
N2 - In this work, we describe the use of artificial neural networks for the quantification of X-ray fluorescence measurements. The training data were generated using Monte Carlo simulation, which avoided the use of adapted reference materials. The extension of the available data set by means of an ANN to generate additional data was demonstrated. Particular emphasis was put on the comparability of simulated and experimental data and how the influence of deviations can be reduced. The search for the optimal hyperparameter, manual and automatic, is also described. For the presented case, we were able to train a network with a mean absolute error of 0.1 weight percent for the synthetic data and 0.7 weight percent for a set of experimental data obtained with certified reference materials.
KW - Machine learning
KW - BAMline
KW - XRF
KW - Synchrotron
KW - Neural network
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519008
DO - https://doi.org/10.1088/2632-2153/abc9fb
SP - 1
EP - 16
PB - IOP Publishing
AN - OPUS4-51900
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Hüsken, Götz
A1 - Wagner, L.-C.
A1 - Gluth, Gregor
A1 - Pirskawetz, Stephan
A1 - Kühne, Hans-Carsten
T1 - Application of Steel Fibres in Alkali-Activated Mortars
N2 - Alkali-activated materials are ideal for the repair of concrete structures in harsh environmental conditions due to their high durability in chemically aggressive environments. However, slag-based mortars, in particular, are prone to shrinkage and associated cracks. In this respect, the application of steel fibres is one solution to reduce the formation of shrinkage induced cracks and to improve post cracking behaviour of these mortars. This study investigated the influence of two different types of steel fibres on the tensile properties of two alkali-activated mortars. Direct tensile tests and single fibre pull-outs were performed to analyse the determining failure modes both on macro and micro scale. Mechanical testing was accompanied by non-destructive testing methods such as digital image correlation and acoustic emission for a detailed analysis of the fracture process.
T2 - Local Mechanical Properties - LMP 2019
CY - Prague, Czech Republic
DA - 06.11.2019
KW - Alkali-activated materials
KW - Fibre pull-out
KW - Steel fibres
KW - Tensile strength
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509291
UR - https://ojs.cvut.cz/ojs/index.php/APP/article/view/6695
DO - https://doi.org/10.14311/APP.2020.27.0090
VL - 27
SP - 90
EP - 95
CY - Prague, Czech Republic
AN - OPUS4-50929
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Smekhova, A.
A1 - Kuzmin, A.
A1 - Siemensmeyer, K.
A1 - Luo, C.
A1 - Taylor, J.
A1 - Thakur, S.
A1 - Radu, F.
A1 - Weschke, E.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Xiao, B.
A1 - Savan, A.
A1 - Yusenko, Kirill
A1 - Ludwig, A.
T1 - Local structure and magnetic properties of a nanocrystalline Mn-rich Cantor alloy thin film down to the atomic scale
N2 - The huge atomic heterogeneity of high-entropy materials along with a possibility to unravel the behavior of individual components at the atomic scale suggests a great promise in designing new compositionally complex systems with the desired multi-functionality. Herein, we apply multi-edge X-ray absorption spectroscopy (extended X-ray absorption fine structure (EXAFS), X-ray absorption near edge structure (XANES), and X-ray magnetic circular dichroism (XMCD)) to probe the structural, electronic, and magnetic properties of all individual constituents in the single-phase face-centered cubic (fcc)-structured nanocrystalline thin film of Cr20Mn26Fe18Co19Ni17 (at.%) high-entropy alloy on the local scale. The local crystallographic ordering and component-dependent lattice displacements were explored within the reverse Monte Carlo approach applied to EXAFS spectra collected at the K absorption edges of several constituents at room temperature. A homogeneous short-range fcc atomic environment around the absorbers of each type with very similar statistically averaged interatomic distances (2.54–2.55 Å) to their nearest-neighbors and enlarged structural relaxations of Cr atoms were revealed. XANES and XMCD spectra collected at the L2,3 absorption edges of all principal components at low temperature from the oxidized and in situ cleaned surfaces were used to probe the oxidation states, the changes in the electronic structure, and magnetic behavior of all constituents at the surface and in the sub-surface volume of the film. The spin and orbital magnetic moments of Fe, Co, and Ni components were quantitatively evaluated. The presence of magnetic phase transitions and the co-existence of different magnetic phases were uncovered by conventional magnetometry in a broad temperature range.
KW - Magnetism
KW - High-entropy alloys
KW - Reverse Monte Carlo (RMC)
KW - Element-specific spectroscopy
KW - Extended X-ray absorption fine structure (EXAFS),
KW - X-ray magnetic circular dichroism (XMCD),
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578254
DO - https://doi.org/10.1007/s12274-022-5135-3
SN - 1998-0124
SP - 5626
PB - Springer
AN - OPUS4-57825
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rudić, O.
A1 - Mittermayr, F.
A1 - Gluth, Gregor
A1 - Simon, Sebastian
A1 - Ukrainczyk, N.
A1 - Seyrek, Y.
A1 - Freytag, B.
A1 - Juhart, J.
A1 - Grengg, C.
T1 - On the benefits of vegetable oil addition for the pore structure and acid resistance of alkali-activated systems
N2 - The impact of high additions of vegetable oil (12 vol%) on the mechanical and microstructural properties of metakaolin-slag-based alkali-activated materials (AAMs) was studied. The addition of oil resulted in a slight decrease in initial polymerization kinetics but did not affect the final degree of reaction. AAM-oil-composite-mortars exhibited approximately ∼30% lower compressive strength primarily due to the entrainment of air voids. Newly formed soap phases significantly reduced the volume of small capillary and gel pores (pore radii <15 nm), leading to a decrease in specific inner surface area by a factor of up to 15. The porosity modification induced by the oil addition greatly enhanced the resistance of AAMs against sulfuric acid attack, shifting the dominant processes from diffusion and cracks to framework-dissolution controlled by the inherent phase stabilities. Following the immersion in sulfuric acid (pHstat = 2) for 8 weeks, the depth of corroded layer decreased by 70% and no cracks due to expansive phases were observed. These promising findings suggest that the incorporation of vegetable oil in AAMs has the potential to address durability concerns associated with diffusion-based corrosion processes, thereby expanding the range of future applications.
KW - Alkali-activated materials
KW - Acid resistance
KW - Pore structure
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581719
DO - https://doi.org/10.1016/j.ceramint.2023.08.036
VL - 49
IS - 20
SP - 33275
EP - 33290
PB - Elsevier Ltd.
AN - OPUS4-58171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mundra, S.
A1 - Samson, G.
A1 - Masi, G.
A1 - Achenbach, R.
A1 - Bastidas, D. M.
A1 - Bernal, S. A.
A1 - Bignozzi, M. C.
A1 - Criado, M.
A1 - Cyr, M.
A1 - Gartner, N.
A1 - von Greve-Dierfeld, S.
A1 - Legat, A.
A1 - Nikoonasab, Ali
A1 - Provis, J. L.
A1 - Raupach, M.
A1 - Gluth, Gregor
T1 - Application of electrochemical methods for studying steel corrosion in alkali-activated materials
N2 - Alkali-activated materials (AAMs) are binders that can complement and partially substitute the current use of conventional cement. However, the present knowledge about how AAMs protect steel reinforcement in concrete elements is incomplete, and uncertainties exist regarding the application of electrochemical methods to investigate this issue. The present review by EFC WP11-Task Force ‘Corrosion of steel in alkali-activated materials’ demonstrates that important differences exist between AAMs and Portland cement, and between different classes of AAMs, which are mainly caused by differing pore solution compositions, and which affect the outcomes of electrochemical measurements. The high sulfide concentrations in blast furnace slag-based AAMs lead to distinct anodic polarisation curves, unusually low open circuit potentials, and low polarisation resistances, which might be incorrectly interpreted as indicating active corrosion of steel reinforcement. No systematic study of the influence of the steel–concrete interface on the susceptibility of steel to corrosion in AAMs is available. Less common electrochemical methods present an opportunity for future progress in the field.
KW - Alkali-activated materials
KW - Reinforcement corrosion
KW - Steel corrrosion
KW - Electrochemical methods
KW - Concrete
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572241
DO - https://doi.org/10.1002/maco.202313743
SN - 1521-4176
VL - 74
IS - 7
SP - 988
EP - 1008
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-57224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vollpracht, A.
A1 - Gluth, Gregor
A1 - Rogiers, B.
A1 - Uwanuakwa, I. D.
A1 - Phung, Q. T.
A1 - Villagran Zaccardi, Y.
A1 - Thiel, C.
A1 - Vanoutrive, H.
A1 - Etcheverry, J. M.
A1 - Gruyaert, E.
A1 - Kamali-Bernard, S.
A1 - Kanellopoulos, A.
A1 - Zhao, Z.
A1 - Martins, I. M.
A1 - Rathnarajan, S.
A1 - De Belie, N.
T1 - Report of RILEM TC 281-CCC: insights into factors affecting the carbonation rate of concrete with SCMs revealed from data mining and machine learning approaches
N2 - The RILEM TC 281–CCC ‘‘Carbonation of concrete with supplementary cementitious materials’’ conducted a study on the effects of supplementary cementitious materials (SCMs) on the carbonation rate of blended cement concretes and mortars. In this context, a comprehensive database has been established, consisting of 1044 concrete and mortar mixes with their associated carbonation depth data over time. The dataset comprises mix designs with a large variety of binders with up to 94% SCMs, collected from the literature as well as unpublished testing reports. The data includes chemical composition and physical properties of the raw materials, mix-designs, compressive strengths, curing and carbonation testing conditions. Natural carbonation was recorded for several years in many cases with both indoor and outdoor results. The database has been analysed to investigate the effects of binder composition and mix design, curing and preconditioning, and relative humidity on the carbonation rate. Furthermore, the accuracy of accelerated carbonation testing as well as possible correlations between compressive strength and carbonation resistance were evaluated. One approach to summerise the physical and chemical resistance in one parameter is the ratio of water content to content of carbonatable CaO (w/CaOreactive ratio). The analysis revealed that the w/CaOreactive ratio is a decisive factor for carbonation resistance, while curing and exposure conditions also influence carbonation. Under natural exposure conditions, the carbonation data exhibit significant variations. Nevertheless, probabilistic inference suggests that both accelerated and natural carbonation processes follow a square-root-of-time behavior, though accelerated and natural carbonation cannot be converted into each other without corrections. Additionally, a machine learning technique was employed to assess the influence of parameters governing the carbonation progress in concretes.
KW - Carbonation
KW - Supplementary cementitious materials
KW - Concrete
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614388
DO - https://doi.org/10.1617/s11527-024-02465-0
SN - 1871-6873
SN - 1359-5997
VL - 57
IS - 9
SP - 1
EP - 33
PB - Springer Nature
AN - OPUS4-61438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tu, Z.
A1 - Donskyi, Ievgen
A1 - Qiao, H.
A1 - Zhu, Z.
A1 - Unger, Wolfgang
A1 - Hackenberger, C. P. R.
A1 - Chen, W.
A1 - Adeli, M.
A1 - Haag, R.
T1 - Graphene Oxide-Cyclic R10 Peptide Nuclear Translocation Nanoplatforms for the Surmounting of Multiple-Drug Resistance
N2 - Multidrug resistance resulting from a variety of defensive pathways in Cancer has become a global concern with a considerable impact on the mortality associated with the failure of traditional chemotherapy. Therefore, further research and new therapies are required to overcome this challenge. In this work, a cyclic R10 peptide (cR10) is conjugated to polyglycerol-covered nanographene oxide to engineer a nanoplatform for the surmounting of multidrug resistance. The nuclear translocation of the nanoplatform, facilitated by cR10 peptide, and subsequently, a laser-triggered release of the loaded doxorubicin result in efficient anticancer activity confirmed by both in vitro and in vivo experiments. The synthesized nanoplatform with a combination of different features, including active nucleus-targeting, highloading capacity, controlled release of cargo, and photothermal property, provides a new strategy for circumventing multidrug resistant cancers.
KW - Graphen Oxide
KW - Nanoplatform
KW - Cancer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510061
DO - https://doi.org/10.1002/adfm.202000933
VL - 30
IS - 35
SP - 2000933
PB - Wiley VCH
AN - OPUS4-51006
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kulka, M.W.
A1 - Nie, C.
A1 - Nickl, P.
A1 - Kerkhoff, Y.
A1 - Garg, A.
A1 - Salz, D.
A1 - Radnik, Jörg
A1 - Grunwald, I.
A1 - Haag, R.
T1 - Surface-Initiated Grafting of Dendritic Polyglycerol from Mussel-Inspired Adhesion-Layers for the Creation of Cell-Repelling Coatings
N2 - Biofouling is a major challenge in the application of textiles, biosensors, and biomedical implants. In the current work, a straightforward method for the solvent-free polymerization of antifouling dendritic polyglycerol (dPG) from mussel-inspired dendritic polyglycerol (MI-dPG) coatings on hydrophilic titanium dioxide (TiO2) and hydrophobic polydimethylsiloxane (PDMS) is reported. Surface characterization is performed by static water contact angle (CA) measurements, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). Significant lower CA values are obtained after dPG grafting from MI-dPG-coated TiO2 and MI-dPG coated PDMS. Furthermore, XPS shows a time-dependent increase of the CO bond content upon dPG grafting from MI-dPG-coated TiO2 and MI-dPG-coated PDMS. Analysis of the surface morphology by SEM shows a clear time-dependent increase in the surface roughness upon dPG grafting from MI-dPG-coated TiO2 and MIdPG-coated PDMS. When the viability of two adhesive cell types is studied via LIVE/DEAD staining, a strong reduction in the cell density is observed after the dPG grafting from MI-dPG-coated TiO2 and MI-dPG-coated PDMS (a decrease of >95% in all cases). The combined results show that biocompatible but highly cell-repelling surfaces are efficiently constructed via the grafting of dPG from MI-dPG-coated TiO2 and MI-dPG-coated PDMS.
KW - Repelling surface coatings
KW - Dendritic polyglycerol
KW - Mussel-inspired adhesives
KW - Surface-initated grafting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516590
DO - https://doi.org/10.1002/admi.202000931
SN - 2196-7350
VL - 7
IS - 24
SP - 931
PB - Wiley VCH
AN - OPUS4-51659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weigert, Florian
A1 - Müller, A.
A1 - Häusler, I.
A1 - Geißler, Daniel
A1 - Skroblin, D.
A1 - Unger, Wolfgang
A1 - Radnik, Jörg
A1 - Resch-Genger, Ute
T1 - Combining HR‑TEM and XPS to elucidate the core–shell structure of ultrabright CdSe/CdS semiconductor quantum dots
N2 - Controlling thickness and tightness of surface passivation shells is crucial for many applications of core–shell nanoparticles (NP). Usually, to determine shell thickness, core and core/shell particle are measured individually requiring the availability of both nanoobjects. This is often not fulfilled for functional nanomaterials such as many photoluminescent semiconductor quantum dots (QD) used for bioimaging, solid state lighting, and display technologies as the core does not show the applicationrelevant functionality like a high photoluminescence (PL) quantum yield, calling for a whole nanoobject approach. By combining high-resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS), a novel whole nanoobject approach is developed representatively for an ultrabright oleic acid-stabilized, thick shell CdSe/CdS QD with a PL quantum yield close to unity. The size of this spectroscopically assessed QD, is in the range of the information depth of usual laboratory XPS. Information on particle size and monodispersity were validated with dynamic light scattering (DLS) and small angle X-ray scattering (SAXS) and compared to data derived from optical measurements. In addition to demonstrating the potential of this novel whole nanoobject approach for determining architectures of small nanoparticles, the presented results also highlight challenges faced by different sizing and structural analysis methods and method-inherent uncertainties.
KW - Photoluminescence
KW - Single particle
KW - Microscopy
KW - Particle architecture
KW - Thickness
KW - SAXS
KW - Shell
KW - XPS
KW - TEM
KW - Semiconductor
KW - Quantum dot
KW - Photophysics
KW - Quantum yield
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517911
DO - https://doi.org/10.1038/s41598-020-77530-z
VL - 10
IS - 1
SP - 20712
PB - Springer Nature
AN - OPUS4-51791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Anja
A1 - Krahl, T.
A1 - Radnik, Jörg
A1 - Wagner, Andreas
A1 - Werner, W. S. M.
A1 - Ritter, B.
A1 - Kemnitz, E.
A1 - Unger, Wolfgang
T1 - Chemical in-depth analysis of (Ca/Sr)F2 core–shell like nanoparticles by X-ray photoelectron spectroscopy with tunable excitation energy
N2 - The fluorolytic sol–gel synthesis is applied with the intention to obtain two different types of core–shell nanoparticles, namely, SrF2–CaF2 and CaF2–SrF2. In two separate fluorination steps for core and shell formation, the corresponding metal lactates are reacted with anhydrous HF in ethylene glycol. Scanning transmission electron microscopy (STEM) and dynamic light scattering (DLS) confirm the formation of particles with mean dimensions between 6.4 and 11.5 nm. The overall chemical composition of the particles during the different reaction steps is monitored by quantitative Al Kα excitation X-ray photoelectron spectroscopy (XPS). Here, the formation of stoichiometric metal fluorides (MF2) is confirmed, both for the core and the final core–shell particles. Furthermore, an in-depth analysis by synchrotron radiation XPS (SR-XPS) with tunable excitation energy is performed to confirm the core–Shell character of the nanoparticles. Additionally, Ca2p/Sr3d XPS intensity ratio in-Depth profiles are simulated using the software Simulation of Electron Spectra for Surface Analysis (SESSA). In principle, core–shell like particle morphologies are formed but without a sharp interface between calcium and strontium containing phases.
Surprisingly, the in-depth chemical distribution of the two types of nanoparticles is equal within the error of the experiment. Both comprise a SrF2-rich core domain and CaF2-rich shell domain with an intermixing zone between them. Consequently, the internal morphology of the final nanoparticles seems to be independent from the synthesis chronology.
KW - Metal fluorides
KW - Sol-gel synthesis
KW - Synchrotron radiation
KW - X-ray photoelectron spectroscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522284
DO - https://doi.org/10.1002/sia.6937
SN - 0142-2421
VL - 53
IS - 5
SP - 494
EP - 508
PB - Wiley VCH
AN - OPUS4-52228
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Müller, Anja
A1 - Radnik, Jörg
A1 - Hachenberger, Y.
A1 - Jungnickel, H.
A1 - Laue, P.
A1 - Luch, A.
A1 - Tentschert, J.
T1 - Preparation of Nanoparticles for ToF-SIMS and XPS Analysis
N2 - Nanoparticles have gained increasing attention in recent years due to their potential and application in different fields including medicine, cosmetics, chemistry, and their potential to enable advanced materials. To effectively understand and regulate the physico-chemical properties and potential adverse effects of nanoparticles, validated measurement procedures for the various properties of nanoparticles need to be developed. While procedures for measuring nanoparticle size and size Distribution are already established, standardized methods for analysis of their surface chemistry are not yet in place, although the influence of the surface chemistry on nanoparticle properties is undisputed. In particular, storage and preparation of nanoparticles for surface analysis strongly influences the analytical results from various methods, and in order to obtain consistent results, sample preparation must be both optimized and standardized. In this contribution, we present, in detail, some standard procedures for preparing nanoparticles for surface analytics. In principle, nanoparticles can be deposited on a suitable substrate from suspension or as a powder. Silicon (Si) Wafers are commonly used as substrate, however, their cleaning is critical to the process. For sample preparation from suspension, we will discuss drop-casting and spin-coating, where not only the cleanliness of the substrate and purity of the suspension but also its concentration play important roles for the success of the preparation methodology.
For nanoparticles with sensitive ligand shells or coatings, deposition as powders is more suitable, although this method requires particular care in fixing the sample.
KW - Titania nanoparticles
KW - X-ray photoelectron spectroscopy
KW - Secondary ion mass spectrometry
KW - Surface chemisttry
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520103
UR - https://www.jove.com/video/61758
DO - https://doi.org/10.3791/61758
VL - 163
SP - e61758
AN - OPUS4-52010
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Donskyi, Ievgen
A1 - Nie, C.
A1 - Ludwig, K.
A1 - Trimpert, J.
A1 - Ahmed, R.
A1 - Quaas, E.
A1 - Achazi, K.
A1 - Radnik, Jörg
A1 - Adeli, M.
A1 - Haag, R.
A1 - Osterrieder, K.
T1 - Graphene Sheets with Defined Dual Functionalities for the Strong SARS-CoV-2 Interactions
N2 - Search of new strategies for the inhibition of respiratory viruses is one of the urgent health challenges worldwide, as most of the current therapeutic agents and treatments are inefficient. Severe acute respiratory syndrome coronavirus 2 (SARSCoV-2) has caused a pandemic and has taken lives of approximately two Million people to date. Even though various vaccines are currently under development, virus, and especially its spike glycoprotein can mutate, which highlights a Need for a broad-spectrum inhibitor. In this work, inhibition of SARS-CoV-2 by graphene platforms with precise dual sulfate/alkyl functionalities is investigated. A series of graphene derivatives with different lengths of aliphatic chains is synthesized and is investigated for their ability to inhibit SARS-CoV-2 and feline coronavirus.
Graphene derivatives with long alkyl chains (>C9) inhibit coronavirus replication by virtue of disrupting viral envelope. The ability of these graphene platforms to rupture viruses is visualized by atomic force microscopy and cryogenic electron microscopy. A large concentration window (10 to 100-fold) where graphene platforms display strongly antiviral activity against native SARS-CoV-2 without significant toxicity against human cells is found. In this concentration range, the synthesized graphene platforms inhibit the infection of enveloped viruses efficiently, opening new therapeutic and metaphylactic avenues against SARS-CoV-2.
KW - Graphene
KW - Graphene-based polyglycerol sulfates
KW - SARS-CoV2 inhibitor
KW - Virucidality
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520858
DO - https://doi.org/10.1002/smll.202007091
VL - 17
IS - 11
SP - 7091
PB - Wiley VCH
AN - OPUS4-52085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hünger, K.-J.
A1 - Kositz, M.
A1 - Danneberg, M.
A1 - Radnik, Jörg
T1 - Enrichment of aluminium in the near‐surface region of natural quartzite rock after aluminium exposure
N2 - Alkali–silica reaction (ASR) is an ongoing problem that causes damage to concrete constructions and reduces their durability. Therefore, minimizing this undesired reaction is of great interest for both safety and economic reasons. Additives containing high aluminium content are very effective in reducing the release of silica and enhancing the durability of concrete; however, the mechanism for this effect is still under discussion. In this study, an enrichment of aluminium in the near‐surface region was observed for natural quartzite rock after storage in Al (OH)3 and metakaolin as aluminium sources, from which we conclude that the formation of aluminosilicate sheets of a few nanometres inhibits the silica release; this hypothesis is supported by high‐resolution spectra of Al 2p, Si 2p and O 1s.
KW - Alkali-silica reaction
KW - Quartzite rock
KW - X-ray photoelectron spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519394
DO - https://doi.org/10.1002/sia.6918
SN - 0142-2421
SP - 1
EP - 7
PB - Wiley VCH
AN - OPUS4-51939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Radnik, Jörg
A1 - Knigge, Xenia
A1 - Andresen, Elina
A1 - Resch-Genger, Ute
A1 - Cant, D.J.H.
A1 - Shard, A.G.
A1 - Clifford, C.A.
T1 - Composition, thickness, and homogeneity of the coating of core–shell nanoparticles—possibilities, limits, and challenges of X-ray photoelectron spectroscopy
N2 - Core–shell nanoparticles have attracted much attention in recent years due to their unique properties and their increasing importance in many technological and consumer products. However, the chemistry of nanoparticles is still rarely investigated in comparison to their size and morphology. In this review, the possibilities, limits, and challenges of X-ray photoelectron spectroscopy (XPS) for obtaining more insights into the composition, thickness, and homogeneity of nanoparticle coatings are discussed with four examples: CdSe/CdS quantum dots with a thick coating and a small core; NaYF4-based upconverting nanoparticles with a large Yb-doped core and a thin Er-doped coating; and two types of polymer nanoparticles with a poly(tetrafluoroethylene) core with either a poly(methyl methacrylate) or polystyrene coating. Different approaches for calculating the thickness of the coating are presented, like a simple numerical modelling or a more complex simulation of the photoelectron peaks. Additionally, modelling of the XPS background for the investigation of coating is discussed. Furthermore, the new possibilities to measure with varying excitation energies or with hard-energy X-ray sources (hard-energy X-ray photoelectron spectroscopy) are described. A discussion about the sources of uncertainty for the determination of the thickness of the coating completes this review.
KW - X-ray spectroscopy
KW - Nanoparticles
KW - Spectroscopy / Instrumentation
KW - Spectroscopy / Theory
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548305
DO - https://doi.org/10.1007/s00216-022-04057-9
VL - 414
IS - 15
SP - 4331
EP - 4345
PB - SpringerNature
AN - OPUS4-54830
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Page, T.M.
A1 - Nie, C.
A1 - Neander, L.
A1 - Povolotsky, T.L.
A1 - Sahoo, A.K.
A1 - Nickl, Philip
A1 - Adler, J.M.
A1 - Bawadkji, O.
A1 - Radnik, Jörg
A1 - Achazi, K.
A1 - Ludwig, K.
A1 - Lauster, D.
A1 - Netz, R.R.
A1 - Trimpert, J.
A1 - Kaufer, B.
A1 - Haag, R.
A1 - Donskyi, Ievgen
T1 - Functionalized Fullerene for Inhibition of SARS-CoV-2 Variants
N2 - As virus outbreaks continue to pose a challenge, a nonspecific viral inhibitor can provide significant benefits, especially against respiratory viruses. Polyglycerol sulfates recently emerge as promising agents that mediate interactions between cells and viruses through electrostatics, leading to virus inhibition.
Similarly, hydrophobic C60 fullerene can prevent virus infection via interactions with hydrophobic cavities of surface proteins. Here, two strategies are combined to inhibit infection of SARS-CoV-2 variants in vitro. Effective inhibitory concentrations in the millimolar range highlight the significance of bare fullerene’s hydrophobic moiety and electrostatic interactions of polysulfates with surface proteins of SARS-CoV-2. Furthermore, microscale thermophoresis measurements support that fullerene linear polyglycerol sulfates interact with the SARS-CoV-2 virus via its spike protein, and highlight importance of electrostatic interactions within it. All-atom molecular dynamics simulations reveal that the fullerene binding site is situated close to the receptor binding domain, within 4 nm of polyglycerol sulfate binding sites, feasibly allowing both portions of the material to interact simultaneously.
KW - Covalent functionalization
KW - Fullerene
KW - SARS-CoV 2
KW - Sulfated materials
KW - Virus inhibition
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568672
DO - https://doi.org/10.1002/smll.202206154
SN - 1613-6810
SP - 1
EP - 8
PB - Wiley VCH
AN - OPUS4-56867
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bawadkji, O.
A1 - Cherri, M.
A1 - Schäfer, A.
A1 - Herziger, S.
A1 - Nickl, Philip
A1 - Achazi, K.
A1 - Donskyi, Ievgen
A1 - Adeli, M.
A1 - Haag, R.
T1 - One-pot covalent functionalization of 2D black phosphorus by anionic ring opening polymerization
N2 - In this work, a one-pot approach for the covalent functionalization of few-layer black phosphorus (BP) by anionic ring opening polymerization of glycidol to obtain multifunctional BP-polyglycerol (BP-PG) with high amphiphilicity for near-infrared-responsive drug delivery and biocompatibility is reported. Straightforward synthesis in combination with exceptional biological and physicochemical properties designates functionalized BP-PG as a promising candidate for a broad range of biomedical applications.
KW - 2D nanomaterial
KW - Amphiphilicity
KW - Black phosphorus
KW - Hyperbranched
KW - Polyglycerol
KW - Water dispersibility
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568833
DO - https://doi.org/10.1002/admi.202201245
SN - 2196-7350
VL - 9
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56883
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Knigge, Xenia
A1 - Radnik, Jörg
T1 - 1,3-Dimethyl-imidazolium dimethyl phosphate ([MMIM]+[DMP]−) analyzed by XPS and HAXPES
N2 - The ionic liquid 1,3-dimethyl-imidazolium-dimethylphosphate ([MMIM]+[DMP]−) was analyzed using (hard) x-ray photoelectron spectroscopy.
Here, XPS and HAXPES spectra are shown in comparison. For the acquisition of the XPS spectra, monochromatic Al Kα radiation at 1486.6 eV was used, while for the acquisition of the HAXPES spectra, monochromatic Cr Kα radiation at 5414.8 eV was applied. Here, survey scans and high-resolution spectra of P 2p, P 2s, C 1s, O 1s, and N 1s for both methods and P 1s, P KL2,3L2,3, and P KL1L2,3 for HAXPES are shown.
KW - C7H15N2O4P
KW - [MMIM]+[DMP]−
KW - Lonic liquid
KW - Hard x-ray photoelectron spectroscopy
KW - HAXPES
KW - XPS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571604
DO - https://doi.org/10.1116/6.0002297
VL - 30
IS - 1
SP - 1
EP - 20
PB - AIP Publishing
AN - OPUS4-57160
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Z.
A1 - Perez, J. P. H.
A1 - Smales, Glen Jacob
A1 - Blukis, R.
A1 - Pauw, Brian Richard
A1 - Stammeier, J. A.
A1 - Radnik, Jörg
A1 - Smith, A. J.
A1 - Benning, L. G.
T1 - Impact of organic phosphates on the structure and composition of short-range ordered iron nanophases
N2 - Organic phosphates (OP) are important nutrient components for living cells in natural environments, where they readily interact with ubiquitous iron phases such as hydrous ferric oxide, ferrihydrite (FHY). FHY partakes in many key bio(geo)chemical reactions including iron-mediated carbon storage in soils, or iron-storage in living organisms. However, it is still unknown how OP affects the formation, structure and properties of FHY. Here, we document how β-glycerophosphate (GP), a model OP ligand, affects the structure and properties of GP–FHY nanoparticles synthesized by coprecipitation at variable nominal molar P/Fe ratios (0.01 to 0.5). All GP–FHY precipitates were characterized by a maximum solid P/Fe ratio of 0.22, irrespective of the nominal P/Fe ratio. With increasing nominal P/Fe ratio, the specific surface area of the GP–FHY precipitates decreased sharply from 290 to 3 m2 g−1, accompanied by the collapse of their pore structure. The Fe–P local bonding environment gradually transitioned from a bidentate binuclear geometry at low P/Fe ratios to monodentate mononuclear geometry at high P/Fe ratios. This transition was accompanied by a decrease in coordination number of edge-sharing Fe polyhedra, and the loss of the corner-sharing Fe polyhedra. We show that Fe(III) polymerization is impeded by GP, and that the GP–FHY structure is highly dependent on the P/Fe ratio. We discuss the role that natural OP-bearing Fe(III) nanophases have in biogeochemical reactions between Fe–P and C species in aquatic systems.
KW - Organic phosphates
KW - Iron nanophases
KW - Scattering
KW - Diffraction
KW - Nanomaterials
KW - Coprecipitation
KW - Carbon storage
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599399
DO - https://doi.org/10.1039/d3na01045g
SN - 2516-0230
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-59939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bennet, Francesca
A1 - Opitz, R.
A1 - Ghoreishi, N.
A1 - Plate, K.
A1 - Barnes, J.-P.
A1 - Bellew, A.
A1 - Bellu, A.
A1 - Ceccone, G.
A1 - de Vito, E.
A1 - Delcorte, A.
A1 - Franquet, A.
A1 - Fumageli, F.
A1 - Gilliland, D.
A1 - Jungnickel, H.
A1 - Lee, T.G.
A1 - Poleunis, C.
A1 - Rading, D.
A1 - Shon, H.K.
A1 - Spampinato, V.
A1 - Son, J.G.
A1 - Wang, F.
A1 - Wang, Y.-C. A.
A1 - Zhao, Y.
A1 - Roloff, A.
A1 - Tentschert, J.
A1 - Radnik, Jörg
T1 - VAMAS TWA2 interlaboratory comparison: Surface analysis of TiO2 nanoparticles using ToF-SIMS
N2 - Due to the extremely high specific surface area of nanoparticles and corresponding potential for adsorption, the results of surface analysis can be highly dependent on the history of the particles, particularly regarding sample preparation and storage. The sample preparation method has, therefore, the potential to have a significant influence on the results. This report describes an interlaboratory comparison (ILC) with the aim of assessing which sample preparation methods for ToF-SIMS analysis of nanoparticles provided the most intra- and interlaboratory consistency and the least amount of sample contamination. The BAM reference material BAM-P110 (TiO2 nanoparticles with a mean Feret diameter of 19 nm) was used as a sample representing typical nanoparticles. A total of 11 participants returned ToF-SIMS data,in positive and (optionally) negative polarity, using sample preparation methods of “stick-and-go” as well as optionally “drop-dry” and “spin-coat.” The results showed that the largest sources of variation within the entire data set were caused by adventitious hydrocarbon contamination or insufficient sample coverage, with the spin-coating protocol applied in this ILC showing a tendency toward insufficient sample coverage; the sample preparation method or the participant had a lesser influence on results.
KW - Secondary Ion Mass Spectrometry
KW - VMAAS
KW - Titania
KW - Interlaboratory comparison
KW - Reproducibility
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582290
DO - https://doi.org/10.1116/6.0002814
SN - 0734-2101
VL - 41
IS - 5
SP - 053210-1
EP - 053210-13
PB - AIP (American Institute of Physics)
AN - OPUS4-58229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hirahara, Kenta
A1 - Bonse, Jörn
A1 - Krüger, Jörg
A1 - Weise, Matthias
A1 - Ermilova, Elena
A1 - Schusterbauer, Robert
A1 - Unterreiner, Andreas-Neil
A1 - Hertwig, Andreas
T1 - A multi-method study of femtosecond laser modification and ablation of amorphous hydrogenated carbon coatings
N2 - e present a study on femtosecond laser treatment of amorphous hydrogen-containing carbon coatings (a-C:H). The coatings were deposited on silicon wafers by a plasma-assisted chemical vapour deposition (PA-CVD), resulting in two different types of material with distinct properties (referred to as “absorbing” and “semi-transparent” coatings in the following).
The samples were laser-treated with single fs-laser pulses (800 nm center wavelength, 35 fs pulse duration) in the ablative regime. Through a multi-method approach using topometry, Raman spectroscopy, and spectroscopic imaging ellipsometry, we can identify zones and thresholds of diferent fuence dependent efects and have access to the local dielectric function.
The two coating materials react signifcantly diferent upon laser treatment. We determined the (non-ablative) modifcation threshold fuence for the absorbing coating as 3.6 × 10−2 Jcm−2 and its ablation threshold as 0.22 Jcm−2. The semi-transparent coating does not show such a low-fuence modifcation but exhibits a characteristic interference-based intra-flm ablation mechanism with two distinguishable ablation thresholds at 0.25 and 0.28 Jcm−2, respectively. The combination of tailored layer materials and correlative imaging spectroscopic methods delivers new insights into the behaviour of materials when treated with ultrashort-pulse laser radiation
KW - Amorphous Hydrogenated Carbon Coatings
KW - Correlative Imaging Measurement Techniques
KW - Hybrid Metrology
KW - Imaging Spectroscopy
KW - Spectroscopic Ellipsometry
KW - Ultra-short Pulse Laser Materials Processing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617829
DO - https://doi.org/10.1007/s00339-024-07980-z
VL - 130
IS - 12
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-61782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Junge, Florian
A1 - Wittwer, Philipp
A1 - Sommerfeld, Thomas
A1 - Gehrenkemper, Lennart
A1 - Zoister, Christian
A1 - Nickl, Philip
A1 - Koch, Matthias
A1 - Meermann, Björn
A1 - Haag, Rainer
T1 - Adsorber Charge Dominates over Hydrophobic or Fluorophilic Functionalization in Influencing Adsorption of PFCA onto Polystyrene Resins
N2 - A systematic series of industrial-relevant polystyrene-based anion exchange resins that are functionalized with hydro- or fluorocarbon chains are compared regarding their adsorption behavior toward perfluorocarboxylic acids (PFCA) in respect to their charge, chain length, and type of chain. The results clearly show the dominance of electrostatic interactions in the adsorption process as uncharged adsorber materials showed no adsorption at all. In contrast, the charged adsorber materials showed in general a PFCA removal of 80% to 30% over the experiment depending on effluent fraction.
Unexpectedly, for perfluorobutanoic acid (PFBA) the highest removal rate is found with consistently >90%. Despite observing significant benefits in the adsorption of PFCA for fluoroalkylated adsorbers in comparison to their non-fluorinated counterparts, this effect of fluoroalkylation is comparatively small and can not be clearly attributed to fluorophilic interactions between the fluoroalkyl chains. These findings help clarifying that the introduction of fluorocarbon moieties in adsorber materials is not necessary in order to remove fluorocarbon molecules from the environment.
KW - PFAS
KW - Remediation
KW - Adsorption
KW - Fluorophilic interactions
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601883
DO - https://doi.org/10.1002/admi.202400199
SN - 2196-7350
SP - 1
EP - 10
PB - John Wiley & Sons
CY - Hoboken, New Jersey, USA
AN - OPUS4-60188
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
T1 - Validation of a low blow specimen technique for R-curve determination using a drop tower
N2 - Fracture mechanics based component design requires appropriate fracture mechanics toughness data with respect to both, loading rate as well as test temperature. Taking high-rate loading into account such as with accidental scenarios, different standards such as ASTM E 1820 or BS 7448-3 provide some information on dynamic fracture mechanics testing. Nevertheless, the designations differ so that a validation of the own material specific test method used for dynamic R-curve determination is mandatory. In order to address this for ductile cast iron materials an experimental method for the reliable determination of dynamic J-integral crack resistance curves at -40 °C following the multiple specimen approach has been established and validated. The experimental concept offers some additional valuable features. Single values of dynamic crack initiation toughness can be determined using a single specimen technique based on crack sensors. Furthermore, an experimentally independent method is provided according to which CTOD δ5 R-curves can be established. The focus of the present paper is on the validation of the experimental low blow technique using a drop tower test system.
A drop tower test system was developed and set up to perform low blow tests at temperatures down to -40 °C. The system allows for a variation of the impact mass and height and was optimized for testing of ductile cast iron at stress intensity rates from approximately 5∙10⁴ to 3∙10⁵ MPa√ms⁻¹. This range of loading rate is characteristic for instance with crash scenarios of heavy sectioned DCI casks for radioactive materials. In order to address characteristic challenges of impact tests (test duration of microseconds up to milliseconds, inertial effects, signal oscillations), an appropriate full bridge strain gage method for the measurement of force directly on the specimen as well as a non-contact measurement of load line displacement using an optical extensometer have been developed and validated.
The low blow test requires either to prevent bouncing strikes of the hammer by using the stop block technique or to catch the hammer after its first strike. Both options are not part of the experimental concept and setup which have been realized here. The paper describes investigations which have been performed in order to make sure that bouncing strikes of the hammer do not cause additional crack extension in the specimen. This is necessary to ensure a unique relation between the work done and the achieved crack extension. The investigations covered the analysis of limit loads of the specimen with respect to the measured force. The measured stiffness of the specimen was assessed and signals of crack sensors were analyzed. Furthermore, an analysis of the mechanical behavior of the loading system and the specimen by optical observation was performed. Corresponding results are discussed in the paper. It had finally been proven that additional crack extension in the specimen due to bouncing strikes of the hammer is not to be expected under the given conditions of test setup, material and loading. It can be seen as a major experimental advantage that the striker does not have to be catched after the low blow test.
T2 - XXIV Italian Group of Fracture Conference
CY - Urbino, Italy
DA - 01.03.2017
KW - Dynamic fracture mechanics
KW - R-curve
KW - Low blow
KW - Ductile cast iron
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-437686
DO - https://doi.org/10.1016/j.prostr.2017.04.005
SN - 2452-3216
VL - 3
SP - 25
EP - 32
AN - OPUS4-43768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Baensch, Franziska
A1 - Hussels, Maria-Teresa
A1 - Chruscicki, Sebastian
A1 - Baer, Wolfram
A1 - Wossidlo, Peter
A1 - Homann, Tobias
A1 - Prager, Jens
A1 - Schmidt, Dirk
A1 - Weltschev, Margit
A1 - Habib, Abdel Karim
T1 - BAM-Projekt AGIFAMOR – Zustandsüberwachung von Rohrleitungen
N2 - Rohrleitungssysteme sind aufgrund ihrer Funktion und Ausdehnung für den Betrieb, die Verfügbarkeit und die Sicherheit von Industrieanlagen von besonderer Bedeutung. Die bisher in definierten Intervallen durchgeführten, wiederkehrenden Prüfungen zur Sicherstellung leckagefreier Rohrleitungen sind kostenintensiv und mit einem erhöhten Aufwand verbunden.
Mit dem interdisziplinären Forschungsprojekt AGIFAMOR (Ageing Infrastructures – Akustisches Monitoring von Rohrleitungen) arbeitet die BAM an der Entwicklung und Erprobung einer örtlich und zeitlich kontinuierlichen Zustandsüberwachung von Rohrleitungen basierend auf einem faseroptischen akustischen Messsystem, welches einen vergleichsweise geringen Installationsaufwand der Sensoren erfordert. Mit diesem Verfahren sollen vor allem betriebsbedingte Schädigungen infolge von Korrosion sowie daraus entstehende Pittings oder Risse erkannt und damit Leckagen verhindert werden.
Im Rahmen einer Machbarkeitsstudie zum Teilaspekt „Detektion von Risswachstum“ wurde ein 2,5 m langes, definiert vorgekerbtes Stahlrohr mit der faseroptischen Sensorik (FOS) ausgestattet und quasistatisch unter 4-Punkt-Biegung belastet. Mit fortschreitender Belastung wächst, ausgehend vom vorhandenen Außenumfangskerb, ein Riss im Stahlrohr bis zum Erreichen der Leckage – in der Praxis ein gefährliches Schadensszenario.
Parallel zur FOS erfolgten Messungen mit Schallemissionssensoren, Beschleunigungssensoren und Potentialsonden, deren Ergebnisse die Interpretation der FOS-Messergebnisse unterstützen sollen.
T2 - 21. Kolloquium Schallemission
CY - Fulda, Germany
DA - 09.03.2017
KW - Beschleunigungssensoren
KW - Faseroptische Sensorik
KW - Schallemission
KW - Monitoring
KW - Rohrleitung
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-401811
SN - 978-3-940283-82-5
VL - DGZfP-BB 159
SP - Vortrag 17, 1
EP - 8
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-40181
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ha, Q. L. M.
A1 - Armbruster, U.
A1 - Atia, Hanan
A1 - Lund, H.
A1 - Agostini, G.
A1 - Radnik, Jörg
A1 - Vuong, H. T.
A1 - Martin, A.
T1 - Development of active and stable low nickel content catalysts for dry reforming of methane
N2 - Methane dry reforming (DRM) was investigated over highly active Ni catalysts with low metal content (2.5wt%) supported on Mg-Al mixed oxide. The aim was to minimize carbon Deposition and metal sites agglomeration on the working catalyst which are known to cause catalyst deactivation.
The solids were characterized using N2 adsorption, X-ray diffraction, temperature-programmed reduction, X-ray photoelectron spectroscopy, and UV-Vis diffuse reflectance spectroscopy. The results showed that MgO-Al2O3 solid solution phases are obtained when calcining Mg-Al hydrotalcite precursor in the temperature range of 550–800 °C. Such phases contribute to the high activity of catalysts with low Ni content even at low temperature (500 °C). Modifying the catalyst preparation with citric acid significantly slows the coking rate and reduces the size of large octahedrally coordinated NiO-like domains, which may easily agglomerate on the surface during DRM. The most effective Ni catalyst shows a stable DRM course over 60 h at high weight hourly space velocity with very low coke deposition. This is a promising result for considering such catalyst systems for further development of an industrial DRM technology.
KW - Dry reforming of methane
KW - Carbon dioxide
KW - Ni
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402904
DO - https://doi.org/10.3390/catal7050157
SN - 2073-4344
VL - 7
IS - 5
SP - 157, 1
EP - 157, 17
PB - MDPI
AN - OPUS4-40290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbas, F.
A1 - Donskyi, Ievgen
A1 - Gholami, M.
A1 - Ziem, B.
A1 - Lippitz, Andreas
A1 - Unger, Wolfgang
A1 - Böttcher, C.
A1 - Rabe, J.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Controlled covalent functionalization of thermally reduced graphene oxide to generate defined bifunctional 2D nanomaterials
N2 - A controlled, reproducible, gram-scale method is reported for the covalent functionalization of graphene Sheets by a one-pot nitrene [2+1] cycloaddition reaction under mild conditions. The reaction between commercially available 2,4,6-trichloro-1,3,5-triazine and sodium azide with thermally reduced graphene oxide (TRGO) results in defined dichlorotriazine-functionalized sheets. The different reactivities of the chlorine substituents on the functionalized graphene allow stepwise post-modification by manipulating the temperature.
This new method provides unique access to defined bifunctional 2D nanomaterials, as exemplified by chiral surfaces and multifunctional hybrid architectures.
KW - Graphene oxide
KW - Bifunctional 2D nanomaterials
KW - XPS
KW - NEXAFS
KW - AFM
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394789
DO - https://doi.org/10.1002/ange.201612422
SN - 1433-7851
VL - 56
IS - 10
SP - 2675
EP - 2679
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-39478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seeburg, Dominik
A1 - Liu, Dongjing
A1 - Radnik, Jörg
A1 - Atia, Hanan
A1 - Pohl, Marga-Martina
A1 - Schneider, Matthias
A1 - Martin, Andreas
A1 - Wohlrab, Sebastian
T1 - Structural changes of highly active Pd/MeOx (Me = Fe, Co, Ni) during catalytic methane combustion
N2 - Fe2O3, Co3O4 and NiO nanoparticles were prepared via a citrate method and further functionalized with Pd by impregnation. The pure oxides as well as Pd/Fe2O3, Pd/Co3O4, and Pd/NiO (1, 5 and 10 wt % Pd) were employed for catalytic methane combustion under methane lean (1 vol %)/oxygen rich (18 vol %, balanced with nitrogen) conditions. Already, the pure metal oxides showed a high catalytic activity leading to complete conversion temperature of T100 ≤ 500 °C. H2-TPR (Temperature-programmed reduction) experiments revealed that Pd-functionalized metal oxides exhibited enhanced redox activity compared to the pure oxides leading to improved catalytic combustion activity at lower temperatures. At a loading of 1 wt % Pd, 1Pd/Co3O4 (T100 = 360 °C) outperforms 1Pd/Fe2O3 (T100 = 410 °C) as well as 1Pd/NiO (T100 = 380 °C). At a loading of 10 wt % Pd, T100 could only be slightly reduced in all cases. 1Pd/Co3O4 and 1Pd/NiO show reasonable stability over 70 h on stream at T100. XPS (X-ray photoelectron spectroscopy) and STEM (Scanning transmission electron microscopy) investigations revealed strong interactions between Pd and NiO as well as Co3O4, respectively, leading to dynamic transformations and reoxidation of Pd due to solid state reactions, which leads to the high long-term stability.
KW - Methane total oxidation
KW - Methane removal
KW - Carbon dioxide
KW - X-ray photoelectron spectroscopy
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-439412
DO - https://doi.org/10.3390/catal8020042
SN - 2073-4344
VL - 8
IS - 2
SP - Article 42, 1
EP - 13
PB - MDPI
AN - OPUS4-43941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Unger, Wolfgang
A1 - Beiranvand, Z.
A1 - Kakanejadifard, A.
A1 - Donskyi, Ievgen
A1 - Faghani, A.
A1 - Tu, Z.
A1 - Lippitz, Andreas
A1 - Sasanpour, P.
A1 - Maschietto, F.
A1 - Paulus, B.
A1 - Haag, R.
A1 - Adeli, M.
T1 - Functionalization of fullerene at room temperature: toward new carbon vectors with improved physicochemical properties
N2 - In this work, fullerene has been functionalized with cyanuric Chloride at room temperature by a nitrene mediated [2 + 1] cycloaddition reaction. The adduct after functionalization is inherently in the form of azafulleroid and shows broad UV absorption in the wavelength range of 200–800 nm, as well as photothermal conversion and fluorescence with a high quantum yield.
KW - Functionalization of fullerenes
KW - XPS
KW - NEXAFS
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-387076
DO - https://doi.org/10.1039/c6ra23419d
SN - 2046-2069
VL - 6
IS - 114
SP - 112771
EP - 112775
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-38707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Broicher, Cornelia
A1 - Zeng, F.
A1 - Pfänder, N.
A1 - Frisch, M.
A1 - Bisswanger, T.
A1 - Radnik, Jörg
A1 - Stockmann, Jörg M.
A1 - Palkovits, S.
A1 - Beine, A. K.
A1 - Palkovits, R.
T1 - Iron and Manganese Containing Multi-Walled Carbon Nanotubes as Electrocatalysts for the Oxygen Evolution Reaction - Unravelling Influences on Activity and Stability
N2 - Hydrogen economy is a central aspect of future energy supply, as hydrogen can be used as energy storage and fuel. In order tomake water electrolysis efficient, the limiting oxygen evolution reaction (OER) needs to be optimized. Therefore, C-based composite materials containing earth-abundant Fe and Mn were synthesized, characterized and tested in the OER. For pyrolysis temperatures above 700°C N-rich multi-walled carbon nanotubes (MWCNT) are obtained. Inside the tubes Fe3C particles are formed, Fe and Mn oxides are incorporated in the carbon matrix and metal spinel nanoparticles cover the outer surface. The best catalyst prepared at 800°C achieves a low overpotential of 389 mV (at 10 mA/cm2) and high stability (22.6 h). From electrochemical measurements and characterization it can be concluded that the high activity is mainly provided by MWCNT, Fe3C and the metal oxides in the conductive carbon matrix. The metal spinel nanoparticles in
contrast protect the MWCNT from oxidation and thereby contribute to the high stability.
KW - Oxygen Evolution Reaction
KW - Carbon Nanotubes
KW - Stability
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513955
DO - https://doi.org/10.1002/cctc.202000944
VL - 12
IS - 21
SP - 1
EP - 8
PB - Wiley Online Libary
AN - OPUS4-51395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stockmann, Jörg M.
A1 - Radnik, Jörg
A1 - Bütefisch, S.
A1 - Busch, I.
A1 - Weimann, T.
A1 - Passiu, C.
A1 - Rossi, A.
A1 - Unger, Wolfgang
T1 - A new test specimen for the determination of the field of view of small-area X-ray photoelectron spectrometers
N2 - Small-area/spot photoelectron spectroscopy (SAXPS) is a powerful tool for the investigation of small surface features like microstructures of electronic devices, sensors or other functional surfaces, and so forth. For evaluating the quality of such microstructures, it is often crucial to know whether a small signal in a spectrum is an unwanted contamination of the field of view (FoV), defined by the instrument settings, or it originated from outside. To address this issue, the d80/20 parameter of a line scan across a chemical edge is often used. However, the typical d80/20 parameter does not give information on contributions from the long tails of the X-ray beam intensity distribution or the electron-optical system as defined by apertures. In the VAMAS TWA2 A22 project “Applying planar, patterned, multi-metallic samples to assess the impact of analysis area in surface-chemical analysis,” new test specimen was developed and tested. The here presented testing material consists of a silicon wafer substrate with an Au-film and embedded Cr circular and square spots with decreasing dimensions from 200 μm down to 5 μm. The spot sizes are traceable to the length unit due to size measurements with a metrological SEM. For the evaluation of the FoV, we determined the Au4f intensities measured with the center of the FoV aligned with the center of the spot and normalized to the Au4f intensity determined on the Au-film. With this test specimen, it was possible to characterize, as an example, the FoV of a Kratos AXIS Ultra DLD XPS instrument.
T2 - ECASIA 2019
CY - Dresden, Germany
DA - 15.09.2019
KW - Field of view
KW - Reference material
KW - Selected area XPS
KW - Small-area XPS
KW - Small-spot XPS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509902
DO - https://doi.org/10.1002/sia.6831
SN - 1096-9918
VL - 52
IS - 12
SP - 890
EP - 894
PB - John Wiley & Sons Ltd
AN - OPUS4-50990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Broichert, C.
A1 - Klingenhof, M.
A1 - Frisch, M.
A1 - Dresp, S.
A1 - Kubo, N.M.
A1 - Artz, J.
A1 - Radnik, Jörg
A1 - Palkovits, S.
A1 - Beine, A.K.
A1 - Strasser, P.
A1 - Palkovits, R.
T1 - Particle size-controlled synthesis of highperformance MnCo-based materials for alkaline OER at fluctuating potentials
N2 - For the large-scale generation of hydrogen via water electrolysis the design of long term stable and active catalysts for the oxygen evolution reaction (OER) remains a key challenge. Most catalysts suffer from severe structural corrosion that becomes even more pronounced at fluctuating potentials. Herein, MnCo based cubic particles were prepared via a hydrothermal approach, in which the edge length of the micron-sized particles can be controlled by changing the pH value of the precursor solution. The cubes are composed of varying amounts of MnCo2O4, CoCO3 and a mixed (Mn/Co)CO3 phase. Structure–activity relationships were deduced revealing a volcano-type behavior for the intrinsic OER activity and fraction of spinel oxide phase.
A low overpotential of 0.37 V at 10 mA cm−2 and a stability of more than 25 h was achieved in 1.0 M KOH using a rotating disc electrode (RDE) setup. The best performing catalyst material was successfully tested under dynamic process conditions for 9.5 h and shows a superior catalytic activity as anode for the Overall water splitting in an electrolyser setup in 1.0 M KOH at 333 K compared to a reference NiCo-spinel catalyst.
KW - Water electrolysis
KW - Oxygen evolution reaction
KW - Structure activity relationships
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536050
DO - https://doi.org/10.1039/d1cy00905b
SN - 2044-4753
VL - 11
IS - 12
SP - 7278
EP - 7286
PB - Royal Society of Chemistry
AN - OPUS4-53605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - WójciaK, K.
A1 - Tokarski, T.
A1 - Cios, G.
A1 - Winkelmann, A.
A1 - Chulist, R.
A1 - Nolze, G.
T1 - Unconventional Applications of Electron Backscattering Diffraction (EBSD) in Metallic Materials
N2 - Electron backscattered diffraction is widely used for phase and orientation imaging of crystalline specimens. Despite the inherent complexity of diffraction images, current analysis methodologies typically focus on the position of Kikuchi bands or direct comparisons between experimental and simulated patterns. These approaches require prior knowledge of the phases to be analyzed, limiting their applicability in certain scenarios. This paper introduces an alternative methodology, crystallographic analysis of lattice metric, which extracts phase and orientation information directly from the registered diffraction pattern without requiring predefined standards. The paper outlines the methodology, discusses limitations, and demonstrates possible application in phase analysis, lattice parameter ratio mapping, and qualitative lattice distortion mapping.
KW - EBSD
KW - Virtual dark-field imaging
KW - Lattice distortion
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656014
DO - https://doi.org/10.24425/amm.2025.156241
VL - 70
IS - 4
SP - 1619
EP - 1626
AN - OPUS4-65601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jägle, Eva
A1 - Tuladhar, Rujika
A1 - Niederleithinger, Ernst
A1 - Epple, Niklas
A1 - Sanchez Trujillo, Camila Andrea
A1 - Gehlen, Christoph
A1 - Timothy, Jithender J.
T1 - Evaluation of ultrasonic signals collected from laboratory concrete specimens: Preprocessing and analysis with coda wave interferometry
N2 - Efficient maintenance of infrastructure relies on monitoring and assessment of its condition. New technologies and methods thereby enable a deeper understanding of the materials used and of the structures built. Coda Wave Interferometry (CWI) is currently explored for continuous monitoring of reinforced concrete structures as well as material testing. This ultrasound-based method is sensitive to even small material alterations and therefore suitable for the detection of initial damage stages. Herein, a step-by-step procedure for the evaluation of ultrasonic signals with CWI methods is presented. The described procedure is proposed for ultrasonic signals collected with embedded ultrasonic transducers with a center frequency of 50 kHz to 70 kHz from prism-shaped concrete specimen with dimensions of 400 mm x 100 mm x 100 mm. The raw ultrasonic signal, preprocessing and CWI analysis are described and influences of parameters within the analysis are discussed. The presented procedure allows systematic and comparable analysis of ultrasonic signals generated with similar conditions and therefore contributes to the application of CWI methods for structural health monitoring and material testing.
KW - Ultrasound
KW - Concrete
KW - Coda wave interferometry
KW - Structural health monitoring
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656027
DO - https://doi.org/10.1016/j.mex.2026.103811
SN - 2215-0161
VL - 16
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-65602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mangarova, Dilyana B.
A1 - Kaufmann, Jan Ole
A1 - Brangsch, Julia
A1 - Kader, Avan
A1 - Möckel, Jana
A1 - Heyl, Jennifer L.
A1 - Verlemann, Christine
A1 - Adams, Lisa C.
A1 - Ludwig, Antje
A1 - Reimann, Carolin
A1 - Poller, Wolfram C.
A1 - Niehaus, Peter
A1 - Karst, Uwe
A1 - Taupitz, Matthias
A1 - Hamm, Bernd
A1 - Weller, Michael G.
A1 - Makowski, Marcus R.
T1 - ADAMTS4-Specific MR Peptide Probe for the Assessment of Atherosclerotic Plaque Burden in a Mouse Model
N2 - Introduction
Atherosclerosis is the underlying cause of multiple cardiovascular pathologies. The present-day clinical imaging modalities do not offer sufficient information on plaque composition or rupture risk. A disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4) is a strongly upregulated proteoglycan-cleaving enzyme that is specific to cardiovascular diseases, inter alia, atherosclerosis.
Materials and Methods
Male apolipoprotein E-deficient mice received a high-fat diet for 2 (n = 11) or 4 months (n = 11). Additionally, a group (n = 11) receiving pravastatin by drinking water for 4 months alongside the high-fat diet was examined. The control group (n = 10) consisted of C57BL/6J mice on standard chow. Molecular magnetic resonance imaging was performed prior to and after administration of the gadolinium (Gd)-based ADAMTS4-specific probe, followed by ex vivo analyses of the aortic arch, brachiocephalic arteries, and carotid arteries. A P value <0.05 was considered to indicate a statistically significant difference.
Results
With advancing atherosclerosis, a significant increase in the contrast-to-noise ratio was measured after intravenous application of the probe (mean precontrast = 2.25; mean postcontrast = 11.47, P < 0.001 in the 4-month group). The pravastatin group presented decreased ADAMTS4 expression. A strong correlation between ADAMTS4 content measured via immunofluorescence staining and an increase in the contrast-to-noise ratio was detected (R2 = 0.69). Microdissection analysis revealed that ADAMTS4 gene expression in the plaque area was significantly greater than that in the arterial wall of a control mouse (P < 0.001). Laser ablation–inductively coupled plasma–mass spectrometry confirmed strong colocalization of areas positive for ADAMTS4 and Gd.
Conclusions
Magnetic resonance imaging using an ADAMTS4-specific agent is a promising method for characterizing atherosclerotic plaques and could improve plaque assessment in the diagnosis and treatment of atherosclerosis.
N2 - Einleitung
Atherosklerose ist die Ursache für zahlreiche Herz-Kreislauf-Erkrankungen. Die derzeitigen klinischen Bildgebungsverfahren liefern keine ausreichenden Informationen über die Zusammensetzung von Plaques oder das Risiko einer Ruptur. A Disintegrin and Metalloproteinase with Thrombospondin Motifs 4 (ADAMTS4) ist ein stark hochreguliertes Proteoglykan-spaltendes Enzym, das unter anderem bei Herz-Kreislauf-Erkrankungen wie Atherosklerose spezifisch auftritt.
Materialien und Methoden
Männliche Apolipoprotein-E-defiziente Mäuse erhielten 2 (n = 11) oder 4 Monate lang (n = 11) eine fettreiche Ernährung. Zusätzlich wurde eine Gruppe (n = 11) untersucht, die 4 Monate lang neben der fettreichen Ernährung Pravastatin über das Trinkwasser erhielt. Die Kontrollgruppe (n = 10) bestand aus C57BL/6J-Mäusen, die mit Standardfutter ernährt wurden. Vor und nach der Verabreichung der gadolinium (Gd)-basierten ADAMTS4-spezifischen Sonde wurde eine molekulare Magnetresonanztomographie durchgeführt, gefolgt von Ex-vivo-Analysen des Aortenbogens, der Arteria brachiocephalica und der Arteria carotis. Ein P-Wert < 0,05 wurde als statistisch signifikanter Unterschied gewertet.
Ergebnisse
Mit fortschreitender Atherosklerose wurde nach intravenöser Anwendung der Sonde ein signifikanter Anstieg des Kontrast-Rausch-Verhältnisses gemessen (Mittelwert vor Kontrastmittelgabe = 2,25; Mittelwert nach Kontrastmittelgabe = 11,47, P < 0,001 in der 4-Monats-Gruppe). Die Pravastatin-Gruppe zeigte eine verminderte ADAMTS4-Expression. Es wurde eine starke Korrelation zwischen dem mittels Immunfluoreszenzfärbung gemessenen ADAMTS4-Gehalt und einem Anstieg des Kontrast-Rausch-Verhältnisses festgestellt (R2 = 0,69). Die Mikrodissektionsanalyse ergab, dass die ADAMTS4-Genexpression im Plaque-Bereich signifikant höher war als in der Arterienwand einer Kontrollmaus (P < 0,001). Laserablation-induktiv gekoppelte Plasma-Massenspektrometrie bestätigte eine starke Kolokalisierung von ADAMTS4- und Gd-positiven Bereichen.
Schlussfolgerungen
Die Magnetresonanztomographie mit einem ADAMTS4-spezifischen Kontrastmittel ist eine vielversprechende Methode zur Charakterisierung atherosklerotischer Plaques und könnte die Plaquebewertung in der Diagnose und Behandlung von Atherosklerose verbessern.
KW - Peptide Aptamer
KW - MRI Probe
KW - Magnetic resonance imaging (MRI)
KW - Peptide libraries
KW - Laser ablation–inductively coupled plasma–mass spectrometry
KW - ICP MS
KW - Imaging
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635832
DO - https://doi.org/10.1097/RLI.0000000000001152
SN - 1536-0210
VL - 60
IS - 8
SP - 499
EP - 507
PB - Ovid Technologies (Wolters Kluwer Health)
CY - Philadelphia, Pennsylvania, USA
AN - OPUS4-63583
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Döring, Sarah
A1 - Konthur, Zoltán
A1 - Weller, Michael G.
A1 - Jaeger, Carsten
A1 - Reinders, Yvonne
T1 - Challenges and Insights in Absolute Quantification of Recombinant Therapeutic Antibodies by Mass Spectrometry: An Introductory Review
N2 - This review describes mass spectrometry (MS)-based approaches for the absolute quantification of therapeutic monoclonal antibodies (mAbs), focusing on technical challenges in sample treatment and calibration. Therapeutic mAbs are crucial for treating cancer and inflammatory, infectious, and autoimmune diseases. We trace their development from hybridoma technology and the first murine mAbs in 1975 to today’s chimeric and fully human mAbs. With increasing commercial relevance, the absolute quantification of mAbs, traceable to an international standard system of units (SI units), has attracted attention from science, industry, and national metrology institutes (NMIs). Quantification of proteotypic peptides after enzymatic digestion using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) has emerged as the most viable strategy, though methods targeting intact mAbs are still being explored. We review peptide-based quantification, focusing on critical experimental steps like denaturation, reduction, alkylation, choice of digestion enzyme, and selection of signature peptides. Challenges in amino acid analysis (AAA) for quantifying pure mAbs and peptide calibrators, along with software tools for targeted MS data analysis, are also discussed. Short explanations within each chapter provide newcomers with an overview of the field’s challenges. We conclude that, despite recent progress, further efforts are needed to overcome the many technical hurdles along the quantification workflow and discuss the prospects of developing standardized protocols and certified reference materials (CRMs) for this goal. We also suggest future applications of newer technologies for absolute mAb quantification.
KW - Monoclonal antibody
KW - Therapeutic antibodies
KW - Mass spectrometry
KW - Liquid chromatography
KW - Absolute quantification
KW - Metrology
KW - Traceability
KW - Certified reference material
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623707
DO - https://doi.org/10.3390/antib14010003
SN - 2073-4468
VL - 14
IS - 1
SP - 1
EP - 26
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-62370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bosc-Bierne, Gaby
A1 - Weller, Michael G.
T1 - Investigation of impurities in peptide pools
T1 - Untersuchung von Verunreinigungen in Peptidpools
N2 - Peptide pools are important research tools in different biomedical fields. They consist of a complex mixture of defined peptides, which places high demands on the production and quality control of these products. Previously it has been shown that the combination of UHPLC with high-resolution mass-spectrometry (HRMS) is a fast and powerful method to confirm the relative concentration and the structural identity of all peptides expected to be in the pool. In this work, the additional information contained in the UV chromatograms and mass spectra is used to search for impurities due to synthesis by-products and degradation during storage and transportation and to identify possible analytical artifacts. It was shown that most impurities are only present in trace amounts and can be considered uncritical for most applications. The most frequent and perhaps unexpected impurities were homo- and heterodimers caused by the free cysteines contained in these peptide pools. Furthermore, pyroglutamate and aspartimide formation, deamidation, methionine oxidation, and amino acid deletions could be found. This list is not intended to be comprehensive, but rather a brief guide to quickly identify impurities and, in the long term, to suggest possible changes in the composition of the peptide pools to avoid such impurities by design or by special precautions.
N2 - Peptidpools sind wichtige Forschungsinstrumente in verschiedenen biomedizinischen Bereichen. Sie bestehen aus einer komplexen Mischung definierter Peptide, was hohe Anforderungen an die Herstellung und Qualitätskontrolle dieser Produkte stellt. In der Vergangenheit wurde gezeigt, dass die Kombination von UHPLC mit hochauflösender Massenspektrometrie (HRMS) eine schnelle und leistungsfähige Methode zur Bestätigung der relativen Konzentration und der strukturellen Identität aller Peptide ist, die in dem Pool erwartet werden. In dieser Arbeit werden die zusätzlichen Informationen, die in den UV-Chromatogrammen und Massenspektren enthalten sind, genutzt, um nach Verunreinigungen zu suchen, die auf Nebenprodukte der Synthese und den Abbau während der Lagerung und des Transports zurückzuführen sind, und um mögliche analytische Artefakte zu identifizieren. Es hat sich gezeigt, dass die meisten Verunreinigungen nur in Spuren vorhanden sind und für die meisten Anwendungen als unkritisch angesehen werden können. Die häufigsten und vielleicht unerwartetsten Verunreinigungen waren Homo- und Heterodimere, die durch die in diesen Peptidpools enthaltenen freien Cysteine verursacht werden. Außerdem wurden Pyroglutamat- und Aspartimidbildung, Deamidierung, Methioninoxidation und Aminosäuredeletionen festgestellt. Diese Liste erhebt keinen Anspruch auf Vollständigkeit, sondern ist eher ein kurzer Leitfaden, um Verunreinigungen schnell zu identifizieren und langfristig mögliche Änderungen in der Zusammensetzung der Peptidpools vorzuschlagen, um solche Verunreinigungen durch Design oder besondere Vorsichtsmaßnahmen zu vermeiden.
KW - Synthetic peptides
KW - Degradation
KW - Synthetic artifacts
KW - Peptide losses
KW - Stability of peptides
KW - Disulfide dimers
KW - Cysteine dimers
KW - Isomers
KW - Cysteine alkylation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626987
DO - https://doi.org/10.3390/separations12020036
SN - 2297-8739
VL - 12
IS - 2
SP - 1
EP - 18
PB - MDPI AG
CY - Basel
AN - OPUS4-62698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Stock, Norbert
A1 - Tadei, Marco
A1 - Demel, Jan
A1 - Cabeza, Aurelio
A1 - Viviani, Riccardo
A1 - Demadis, Konstantinos
A1 - Vassaki, Maria
T1 - New directions in metal phosphonate and phosphinate chemistry
N2 - In September 2018, the First European Workshop on Metal Phosphonates Chemistry brought together some prominent researchers in the field of metal phosphonates and phosphinates with the aim of discussing past and current research efforts and identifying future directions. The scope of this perspective article is to provide a critical overview of the topics discussed during the workshop, which are divided into two main areas: synthesis and characterisation, and applications. In terms of synthetic methods, there has been a push towards cleaner and more efficient approaches. This has led to the introduction of high-throughput synthesis and mechanochemical synthesis. The recent success of metal–organic frameworks has also promoted renewed interest in the synthesis of porous metal phosphonates and phosphinates. Regarding characterisation, the main advances are the development of electron diffraction as a tool for crystal structure determination and the deployment of in situ characterisation techniques, which have allowed for a better understanding of reaction pathways. In terms of applications, metal phosphonates have been found to be suitable materials for several purposes: they have been employed as heterogeneous catalysts for the synthesis of fine chemicals, as solid sorbents for gas separation, notably CO2 capture, as materials for electrochemical devices, such as fuel cells and rechargeable batteries, and as matrices for drug delivery.
KW - Metal phosphonates
KW - Metal–organic frameworks
KW - X-ray and electron diffraction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-484346
DO - https://doi.org/10.3390/cryst9050270
SN - 2073-4352
VL - 9
IS - 5
SP - 270, 1
EP - 36
PB - MDPI
AN - OPUS4-48434
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Burek, K.
A1 - Dengler, J.
A1 - Emmerling, Franziska
A1 - Feldmann, Ines
A1 - Kumke, M. U.
A1 - Stroh, Julia
T1 - Lanthanide Luminescence Revealing the Phase Composition in Hydrating Cementitious Systems
N2 - The hydration process of Portland cement in a cementitious system is crucial for development of the high-quality cementbased construction material. Complementary experiments of Xray diffraction analysis (XRD), scanning electron microscopy (SEM) and time-resolved laser fluorescence spectroscopy (TRLFS) using europium (Eu(III)) as an optical probe are used to analyse the hydration process of two cement systems in the absence and presence of different organic admixtures.
We Show that different analysed admixtures and the used sulphate carriers in each cement system have a significant influence on the hydration process, namely on the time-dependence in the formation of different hydrate phases of cement. Moreover, the effect of a particular admixture is related to the type of sulphate carrier used.
The quantitative information on the amounts of the crystalline cement paste components is accessible via XRD analysis. Distinctly different morphologies of ettringite and calcium-silicate-hydrates (C-S-H) determined by SEM allow visual conclusions about formation of these phases at particular ageing times. The TRLFS data provides information about the admixture influence on the course of the silicate reaction. The dip in the dependence of the luminescence decay times on the hydration time indicates the change in the structure of C-S-H in the early hydration period. Complementary information from XRD, SEM and TRLFS provides detailed information on distinct periods of the cement hydration process.
KW - Cement admixtures
KW - Cement hydration
KW - Europium
KW - Luminescence
KW - SEM
KW - X-ray diffraction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504842
DO - https://doi.org/10.1002/open.201900249
VL - 8
IS - 12
SP - 1441
EP - 1452
PB - Wiley-VCH
AN - OPUS4-50484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belenguer, A.
A1 - Michalchuk, Adam
A1 - Lampronti, G
A1 - Sanders, J
T1 - Understanding the unexpected effect of frequency on the kinetics of a covalent reaction under ball-milling conditions
N2 - We here explore how ball-mill-grinding frequency affects the kinetics of a disulfide exchange reaction. Our kinetic data show that the reaction progress is similar at all the frequencies studied (15–30 Hz), including a significant induction time before the nucleation and growth process starts. This indicates that to start the reaction an initial energy accumulation is necessary. Other than mixing, the energy supplied by the mechanical treatment has two effects: (i) reducing the crystal size and (ii) creating defects in the structure. The crystal-breaking process is likely to be dominant at first becoming less important later in the process when the energy supplied is stored at the molecular level as local crystal defects. This accumulation is taken here to be the rate-determining step. We suggest that the local defects accumulate preferentially at or near the crystal surface. Since the total area increases exponentially when the crystal size is reduced by the crystal-breaking process, this can further explain the exponential dependence of the onset time on the milling frequency.
KW - Mechanochemistry
KW - Kinetics
KW - Diffraction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483361
DO - https://doi.org/10.3762/bjoc.15.120
SN - 2195-951X
VL - 15
SP - 1226
EP - 1235
PB - Beilstein-Institut zur Förderung der Chemischen Wissenschaften
CY - Frankfurt, M.
AN - OPUS4-48336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stroh, Julia
A1 - Feiler, Torvid
A1 - Ali, N. Z.
A1 - Minas da Piedade, M. E.
A1 - Emmerling, Franziska
T1 - Mechanistic Insights into a Sustainable Mechanochemical Synthesis of Ettringite
N2 - Mechanochemistry offers an environmentally benign and facile synthesis method for a variety of cement paste constituents. In addition, these methods can be used to selectively tune the properties of cement components. The mineral ettringite is an important component of cementitious materials and has additional technological potential due to its ion exchange properties.
Synthesis of ettringite via mechanochemistry is an environmentally friendly alternative to conventional wet-chemical synthesis established in industry. This contribution explores the mechanism of a two-step mechanochemical synthesis of ettringite, which was previously found to greatly improve the reaction conversion as compared with one-pot synthesis. The crystallinity of Al(OH)3 was found to decrease during the first stage of this mechanochemical synthesis. This was correlated to a significant decrease in the particle size of Al(OH)3 in this stage. No other significant changes were found for the other components, suggesting that mechanochemical activation of Al(OH)3 is responsible for the enhanced formation of ettringite by the two-step approach. The environmentally friendly approach developed for ettringite synthesis offers a versatile synthetic strategy, which can be applied to synthesise further cementitious materials.
KW - Ettringite
KW - Mechanochemistry
KW - Sustainability
KW - X-ray diffraction
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489172
DO - https://doi.org/10.1002/open.201900215
VL - 8
IS - 7
SP - 1012
EP - 1019
PB - ChemPubSoc
AN - OPUS4-48917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haferkamp, Sebastian
A1 - Paul, Andrea
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - Unexpected polymorphism during a catalyzed mechanochemical Knoevenagel condensation
N2 - The transformation of a base-catalyzed, mechano-assisted Knoevenagel condensation of mono-fluorinated benzaldehyde derivatives (p-, m-, o-benzaldehyde) with malonodinitrile was investigated in situ and in real time. Upon milling, the para-substituted product was found to crystallize initially into two different polymorphic forms, depending on the quantity of catalyst used. For low catalyst concentrations, a mechanically metastable phase (monoclinic) was initially formed, converting to the mechanically stable phase (triclinic) upon further grinding. Instead, higher catalyst concentrations crystallize directly as the triclinic product. Inclusion of catalyst in the final product, as evidenced by mass spectrometric analysis, suggests this complex polymorphic pathway may be due to seeding effects. Multivariate analysis for the in situ Raman spectra supports this complex formation pathway, and offers a new approach to monitoring multi-phase reactions during ball milling.
KW - Ball milling
KW - C-C coupling
KW - In situ
KW - Mechanochemistry
KW - Multivariate data analysis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481872
DO - https://doi.org/10.3762/bjoc.15.110
SN - 1860-5397
VL - 15
SP - 1141
EP - 1148
PB - Beilstein Insitut
CY - Frankfurt am Main
AN - OPUS4-48187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stroh, Julia
A1 - Ali, Naveed Zafar
A1 - Maierhofer, Christiane
A1 - Emmerling, Franziska
T1 - Ettringite via Mechanochemistry: A Green and Rapid Approach for Industrial Application
N2 - Here, we report on a first mechanochemical synthesis of ettringite, an important cement hydrate phase. The mineral compound ettringite ([Ca3Al(OH)6]2·(SO4)3·26H2O) occurs rarely in nature, but is common for cement-based materials. Ettringite has wide technical application in the ceramic and paper industry. However, its typical wet-chemical synthesis is cumbersome and produces waste water and CO2 emissions. Here, we investigate the first mechanochemical synthesis of ettringite for developing an easy and sustainable alternative for industrial application. The mechanosynthesis was monitored in situ by coupled synchrotron X-ray diffraction (XRD) and infrared thermography (IRT). The consumption of the reactants and the formation of the reaction product were monitored with time-resolved XRD. IRT showed the temperature increase based on the exothermic reaction. The reaction conversion was significantly improved changing the strategy of the mechanosynthesis from a one- to a two-step process. The latter included neat pregrinding of solid reactants followed by a delayed addition of the stoichiometric amount of water. Thus, an increase of reaction conversion from 34 to 94% of ettringite could be achieved.
KW - XRD
KW - Mechanochemistry
KW - Ettringite
KW - In situ
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479016
DO - https://doi.org/10.1021/acsomega.9b00560
SN - 2470-1343
VL - 4
IS - 4
SP - 7734
EP - 7737
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-47901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beyer, Sebastian
A1 - Schürmann, Robin
A1 - Feldmann, Ines
A1 - Blocki, A.
A1 - Bald, Ilko
A1 - Schneider, Rudolf
A1 - Emmerling, Franziska
T1 - Maintaining Stable Zeolitic Imidazolate Framework (ZIF) Templates during Polyelectrolyte Multilayer Coating
N2 - Equipping ZIF particles with a polyelectrolyte membrane provides functional groups at their interface, enabling further conjugations necessary for applications such as targeted drug delivery. Previous approaches to coat ZIF particles with polyelectrolytes led to surface corrosion of the template material. This work overcomes previous limitations by performing a Layer-by-Layer (LbL) polyelectrolyte coating onto ZIF-8 and ZIF-67 particles in nonaqueous environment. Using the 2-methylimidazolium salt of polystyrensulfonic acid instead of the acid itself and polyethyleneimine in methanol led to intact ZIF particles after polyelectrolyte coating. This was verified by electron microscopy. Further, zetapotential and atomic force microscopy measurements confirmed a continuous polyelectrolyte multilayer built up. The here reported adaption to the well-studied (LbL) polyelectrolyte selfassembly process provides a facile method to equip ZIF particles with a nanometer thin polyelectrolyte multilayer membrane.
KW - Zeolithe
KW - Molecular Organic Frameworks
KW - MOF
KW - ZIF
KW - Layer-by-Layer
KW - Beschichtung
KW - Polyelektrolyt
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447729
DO - https://doi.org/10.1016/j.colcom.2017.11.004
SN - 2215-0382
VL - 22
SP - 14
EP - 17
PB - Elsevier B.V.
CY - Amsterdam, NL
AN - OPUS4-44772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Boldyreva, E.
A1 - Belenguer, A. M.
A1 - Emmerling, Franziska
A1 - Boldyrev, V. V.
T1 - Tribochemistry, mechanical alloying, mechanochemistry: what is in a name?
N2 - Over the decades, the application of mechanical force to influence chemical reactions has been called by various names: mechanochemistry, tribochemistry, mechanical alloying, to name but a few. The evolution of these terms has largely mirrored the understanding of the field. But what is meant by these terms, why have they evolved, and does it really matter how a process is called? Which parameters should be defined to describe unambiguously the experimental conditions such that others can reproduce the results, or to allow a meaningful comparison between processes explored under different conditions? Can the information on the process be encoded in a clear, concise, and self-explanatory way? We address these questions in this Opinion contribution, which we hope will spark timely and constructive discussion across the international mechanochemistry community.
KW - Mechanochemistry
KW - Tribochemistry
KW - Mechanical alloying
KW - Tribology
KW - Mechanical activation
KW - Nomenclature
KW - Mechanochemical pictographs
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523291
DO - https://doi.org/10.3389/fchem.2021.685789
SN - 2296-2646
VL - 9
SP - 1
EP - 29
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-52329
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira, P. F. M.
A1 - Torresi, R.
A1 - Emmerling, Franziska
A1 - Carmago, P.
T1 - Challenges and opportunities in the bottom-up mechanochemical synthesis of noble metal nanoparticles
N2 - Mechanochemistry is a promising alternative to solution-based protocols across the chemical sciences, enabling different types of chemistries in solvent-free and environmentally benign conditions. The use of mechanical energy to promote physical and chemical transformations has reached a high level of refinement, allowing for the design of sophisticated molecules and nanostructured materials. Among them, the synthesis of noble metal nanoparticles deserves special attention due to their catalytic applications. In this review, we discuss the recent progress on the development of mechanochemical strategies for the controlled synthesis of noble metal nanostructures. We start by covering the fundamentals of different preparation routes, namely top-down and bottom-up approaches. Next, we focus on the key examples of the mechanochemical synthesis of non-supported and supported metal nanoparticles as well as hybrid nanomaterials containing noble metals. In these examples, in addition to the principles and synthesis mechanisms, their performances in catalysis are discussed. Finally, a perspective of the field is given, where we discuss the opportunities for future work and the challenges of mechanochemical synthesis to produce well-defined noble metal nanoparticles.
KW - Mechanochemistry
KW - Nanoparticles
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512080
DO - https://doi.org/10.1039/D0TA05183G
VL - 8
IS - 32
SP - 16114
AN - OPUS4-51208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Schröder, V.
A1 - List-Kratochvil, E.
A1 - Emmerling, Franziska
T1 - Mechanochemical Syntheses of Isostructural Luminescent Cocrystals of 9-Anthracenecarboxylic Acid with two Dipyridines Coformers
N2 - Tuning and controlling the solid-state photophysical properties of organic luminophore are very important to develop next-generation organic luminescent materials. With the aim of discovering new functional luminescent materials, new cocrystals of 9-anthracene carboxylic acid (ACA) were prepared with two different dipyridine coformers: 1,2-bis(4-pyridyl)ethylene and 1,2-bis(4-pyridyl)ethane. The cocrystals were successfully obtained by both mechanochemical approaches and conventional solvent crystallization. The newly obtained crystalline solids were characterized thoroughly using a combination of single crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and thermogravimetric analysis. Structural analysis revealed that the cocrystals are isostructural, exhibiting two-fold interpenetrated hydrogen bonded networks. While the O–H···N hydrogen bonds adopts a primary role in the stabilization of the cocrystal phases, the C–H···O hydrogen bonding interactions appear to play a significant role in guiding the three-dimensional assembly. Both π···π and C–H···π interactions assist in stabilizing the interpenetrated structure. The photoluminescence properties of both the starting materials and cocrystals were examined in their solid states. All the cocrystals display tunable photophysical properties as compared to pure ACA. Density functional theory simulations suggest that the modified optical properties result from charge transfers between the ACA and coformer molecules in each case. This study demonstrates the potential of crystal engineering to design solid-state luminescence switching materials through cocrystallization.
KW - Cocrystal
KW - Mechanochemical synthesis
KW - Luminescence
KW - X-ray diffraction
KW - DFT calculation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518226
DO - https://doi.org/10.3390/cryst10100889
VL - 10
IS - 10
SP - 889
PB - MDPI
AN - OPUS4-51822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kervarec, M.-C.
A1 - Kemnitz, E.
A1 - Scholz, G.
A1 - Rudic, S.
A1 - Jäger, Christian
A1 - Braun, T.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - A HF Loaded Lewis-Acidic Aluminium Chlorofluoride for Hydrofluorination Reactions
N2 - The very strong Lewis acid aluminium chlorofluo-ride (ACF) was loaded with anhydrous HF. The interactionbetween the surface of the catalyst and HF was investigatedusing a variety of characterization methods, which revealed he formation of polyfluorides. Moreover, the reactivity ofthe HF-loaded ACF towards the hydrofluorination of alkyneswas studied.
KW - Aluminium
KW - HF
KW - Hydrofluorination
KW - Metal fluorides
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508360
DO - https://doi.org/10.1002/chem.202001627
VL - 26
SP - 1
PB - Wiley Online Libary
AN - OPUS4-50836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, A.
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L. J.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol Dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment.
The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled Plasma mass spectrometry (ICP-MS), infrared (IR) spectroscopy, 151Eu-Mössbauer spectroscopy, X-ray total scattering, and Extended X-ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve Separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - Lanthanides
KW - Structural Analysis
KW - Separation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510821
DO - https://doi.org/10.1002/chem.202002653
SN - 0947-6539
VL - 26
SP - 1
EP - 8
PB - WILEY-VCH Verlag GmbH & co. KGaA
AN - OPUS4-51082
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lumpe, H.
A1 - Menke, Annika
A1 - Haisch, C.
A1 - Mayer, P.
A1 - Kabelitz, Anke
A1 - Yusenko, Kirill
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Block, T.
A1 - Pöttgen, R.
A1 - Emmerling, Franziska
A1 - Daumann, L.
T1 - The Earlier the Better: Structural Analysis and Separation of Lanthanides with Pyrroloquinoline Quinone
N2 - Lanthanides (Ln) are critical raw materials, however, their mining and purification have a considerable negative environmental impact and sustainable recycling and separation strategies for these elements are needed. In this study, the precipitation and solubility behavior of Ln complexes with pyrroloquinoline quinone (PQQ), the cofactor of recently discovered lanthanide (Ln) dependent methanol dehydrogenase (MDH) enzymes, is presented. In this context, the molecular structure of a biorelevant europium PQQ complex was for the first time elucidated outside a protein environment. The complex crystallizes as an inversion symmetric dimer, Eu2PQQ2, with binding of Eu in the biologically relevant pocket of PQQ. LnPQQ and Ln1Ln2PQQ complexes were characterized by using inductively coupled plasma mass spectrometry (ICP‐MS), infrared (IR) spectroscopy, 151Eu‐Mössbauer spectroscopy, X‐ray total scattering, and extended X‐ray absorption fine structure (EXAFS). It is shown that a natural enzymatic cofactor is capable to achieve separation by precipitation of the notoriously similar, and thus difficult to separate, lanthanides to some extent.
KW - PQQ
KW - Lanthanoide
KW - Coordination chemistry
KW - Rare earth elements separations
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512707
DO - https://doi.org/10.1002/chem.202002653
VL - 26
IS - 44
SP - 10133
EP - 10139
AN - OPUS4-51270
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tantardini, C.
A1 - Michalchuk, Adam
A1 - Samtsevich, A.
A1 - Rota, C.
A1 - Kvashnin, A. G.
T1 - The Volumetric Source Function: Looking Inside van der Waals Interactions
N2 - The study of van der Waals interactions plays a central role in the understanding of bonding across a range of biological, chemical and physical phenomena. The presence of van der Waals interactions can be identified through analysis of the reduced density gradient, a fundamental parameter at the core of Density Functional Theory. An extension of Bader’s Quantum Theory of Atoms in Molecules is developed here through combination with the analysis of the reduced density gradient. Through this development, a new quantum chemical topological tool is presented: the volumetric source function.
This technique allows insight into the atomic composition of van der Waals interactions, offering the first route towards applying the highly successful source function to these disperse interactions. A new algorithm has been implemented in the open-source code, CRITIC2, and tested on acetone, adipic and maleic acids molecular crystals, each stabilized by van der Waals interactions. This novel technique for studying van der Waals interactions at an atomic level offers unprecedented opportunities in the fundamental study of intermolecular interactions and molecular design for crystal engineering, drug design and bio-macromolecular processes.
KW - Noncovalent interactions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507911
DO - https://doi.org/10.1038/s41598-020-64261-4
VL - 10
IS - 1
SP - 7816
AN - OPUS4-50791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quiroz, J.
A1 - de Oliveira, P. F. M.
A1 - Shetty, S.
A1 - Oropeza, F.
A1 - Peña O’Shea, V.
A1 - Rodrigues, L.
A1 - Rodrigues, M.
A1 - Torresi, R.
A1 - Emmerling, Franziska
A1 - Camargo, P.
T1 - Bringing earth-abundant plasmonic catalysis to light: Gram-scale mechanochemical synthesis and tuning of activity by dual excitation of antenna and reactor sites
N2 - The localized surface plasmon resonance (LSPR) excitation in plasmonic nanoparticles (NPs) in the visible and near-infrared ranges is currently at the forefront of improving photocatalytic performances via plasmonic photocatalysis. One bottleneck of this field is that the NPs that often display the best optical properties in the visible and near-infrared ranges are based on expensive noble metals such as silver (Ag) and gold (Au). While earth-abundant plasmonic materials have been proposed together with catalytic metals in antenna–reactor systems, their performances remain limited by their optical properties. Importantly, the synthesis of plasmonic photocatalysts remains challenging in terms of scalability while often requiring several steps, high temperatures, and special conditions. Herein, we address these challenges by developing a one-pot, gram-scale, room-temperature synthesis of earth-abundant plasmonic photocatalysts while improving their activities beyond what has been dictated by the LSPR excitation of the plasmonic component. We describe the mechanochemical synthesis of earth-abundant plasmonic photocatalysts by using MoO3 (antenna) and Au (reactor) NPs as a proof-of-concept example and demonstrate that the dual plasmonic excitation of antenna and reactor sites enables the tuning of plasmonic photocatalytic performances toward the reductive coupling of nitrobenzene to azobenzene as a model reaction. In addition to providing a pathway to the facile and gram-scale synthesis of plasmonic photocatalysts, the results reported herein may open pathways to improved activities in plasmonic catalysis.
KW - MoO3
KW - Au nanoparticles
KW - Localized surface plasmon resonance
KW - Plasmonic photocatalysis
KW - Nitrobenzene reduction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532089
DO - https://doi.org/10.1021/acssuschemeng.1c02063
VL - 9
IS - 29
SP - 9750
EP - 9760
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-53208
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bornemann-Pfeiffer, Martin
A1 - Wolf, Jakob
A1 - Meyer, Klas
A1 - Kern, S.
A1 - Angelone, D.
A1 - Leonov, A.
A1 - Cronin, L.
A1 - Emmerling, Franziska
T1 - Standardization and control of Grignard reactions in a universal chemical synthesis machine using online NMR
T1 - Standardisierung und Kontrolle von Grignard-Reaktionen mittels Online-NMR in einer universellen chemischen Syntheseplattform
N2 - A big problem with the chemistry literature is that it is not standardized with respect to precise operational parameters, and real time corrections are hard to make without expert knowledge. This lack of context means difficult reproducibility because many steps are ambiguous, and hence depend on tacit knowledge. Here we present the integration of online NMR into an automated chemical synthesis machine (CSM aka. “Chemputer” which is capable of small-molecule synthesis using a universal programming language) to allow automated analysis and adjustment of reactions on the fly. The system was validated and benchmarked by using Grignard reactions which were chosen due to their importance in synthesis. The system was monitored in real time using online-NMR, and spectra were measured continuously during the reactions. This shows that the synthesis being done in the Chemputer can be dynamically controlled in response to feedback optimizing the reaction conditions according to the user requirements.
N2 - Ein Problem der chemischen Literatur ist die fehlende Standardisierung bezüglich genauer Bedingungen, auch Echtzeit-Korrekturen sind ohne Expertenwissen nur schwer möglich. Dieser Mangel an Details erschwert experimentelle Reproduzierbarkeit, da Schritte oft mehrdeutig sind und daher von implizitem Wissen abhängen. Hier präsentieren wir die Integration von Online-NMR Spektroskopie in eine automatisierte chemische Syntheseplattform (CSM aka. “Chemputer”, unter Verwendung einer universellen Programmiersprache zur Synthese kleiner Moleküle fähig), um eine automatisierte Analyse und Anpassung von Reaktionen im laufenden Betrieb zu ermöglichen. Das System wurde anhand von Grignard-Reaktionen, die aufgrund ihrer Bedeutung für die Synthese ausgewählt wurden, validiert und einem Härtetest unterzogen. Synthesen wurden in Echtzeit mit Online-NMR überwacht, und die Spektren wurden während der Reaktionen kontinuierlich aufgenommen und analysiert. Dies zeigt, dass der Chemputer dynamisch mittels einer Regelung kontrolliert werden kann, um die Reaktionsbedingungen entsprechend den Anforderungen des Benutzers zu optimieren.
KW - Grignard reaction
KW - NMR spectroscopy
KW - Process analytical technology
KW - Process control
KW - Grignard-Reaktion
KW - NMR-Spektroskopie
KW - Prozessanalytik
KW - Prozesskontrolle
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531260
DO - https://doi.org/10.1002/anie.202106323
SN - 1521-3773
SN - 1433-7851
N1 - Bibliografische Angaben für die deutsche Version: Angewandte Chemie 2021, Jg. 133, S. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323 - Bibliographic information for the German version: Angewandte Chemie 2021, vol. 133, p. 1–7, ISSN 0044-8249, ISSN 1521-3757, https://doi.org/10.1002/ange.202106323
VL - 60
IS - 43
SP - 1
EP - 6
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53126
LA - mul
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Christopher, I
A1 - Michalchuk, Adam
A1 - Pulham, C.
A1 - Morrison, C.
T1 - Towards Computational Screening for New Energetic Molecules: Calculation of Heat of Formation and Determination of Bond Strengths by Local Mode Analysis
N2 - The reliable determination of gas-phase and solid-state heats of formation are important considerations in energetic materials research. Herein, the ability of PM7 to calculate the gas-phase heats of formation for CNHO-only and inorganic compounds has been critically evaluated, and for the former, comparisons drawn with isodesmic equations and Atom equivalence methods. Routes to obtain solid-state heats of formation for a range of singlecomponent molecular solids, salts, and co-crystals were also evaluated. Finally, local vibrational mode analysis has been used to calculate bond length/force constant curves for seven different chemical bonds occurring in CHNO-containing molecules, which allow for rapid identification of the weakest bond, opening up great potential to rationalise decomposition pathways. Both metrics are important tools in rationalising the design of new energetic materials through computational screening processes.
KW - Energetic materials
KW - Density functional theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530371
DO - https://doi.org/10.3389/fchem.2021.726357
VL - 9
SP - 726357
AN - OPUS4-53037
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Rhim, S.-Y.
A1 - Schöder, V.
A1 - List-Kratochvil, E.
A1 - Emmerling, Franziska
T1 - Tuning the mechanical flexibility of organic molecular crystals by polymorphism for flexible optical waveguides
N2 - The ability to selectively tune the optical and the mechanical properties of organic molecular crystals offers a promising approach towards developing flexible optical devices. These functional properties are sensitive to crystallographic packing features and are hence expected to vary with polymorphic modification. Using as a model system the photoluminescent material 4-bromo-6-[(6-chloropyridin-2-ylimino)methyl]phenol (CPMBP), we herein demonstrate the simultaneous tuning of mechanical flexibility and photoluminescence properties via polymorphism. Two new polymorphic forms of CPMBP were obtained from a solution and fully characterised using a combination of experiments and density functional theory simulations. These polymorphic forms exhibit remarkably distinct mechanical properties and an order of magnitude difference in photoluminescence quantum yield. The mechanically plastic form has a higher quantum yield than the brittle polymorphic form. However, their photoluminescence emission profile is largely unaffected by the observed polymorphism, thereby demonstrating that the optical properties and bulk mechanical properties can in principle be tuned independently. By distinguishing between active (involving absorption and emission) and passive (involving no absorption) light propagation, the waveguiding properties of the plastic form of CPMBP (form II) were explored using the straight and bent crystals to highlight the potential applications of CPMBP in designing flexible optical devices. Our results demonstrated that polymorph engineering would be a promising avenue to achieve concurrent modulation of the optical and mechanical properties of photoluminescent molecular crystals for next-generation flexible optical device applications.
KW - Mechanochemistry
KW - Flexible
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532075
DO - https://doi.org/10.1039/d1ce00642h
VL - 23
IS - 34
SP - 5815
EP - 5825
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-53207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, G.
A1 - Xu, W.
A1 - Kemnitz, E.
A1 - Emmerling, Franziska
T1 - Structure and properties of fluorinated and non-fluorinated Ba-coordination polymers - the position of fluorine makes the difference
N2 - As the most electronegative element, fluorine has a strong influence on material properties such as absorption behaviour or chemical and thermal stability. Fluorine can be easily integrated into coordination polymers (CPs) via a fluorinated acetate, here trifluoroacetate in Ba(CF3COO)2, or directly via a metal fluorine bond (BaF(CH3COO)). In the present study both possibilities of fluorine integration were tested and their effect on structure and properties of barium coordination polymers was investigated in comparison with the non-fluorinated barium acetate (Ba(CH3COO)2). In addition to the study of their thermal behaviour and their decomposition temperature, the CPs structures were tested for their application as possible anode materials in lithium ion batteries and for their sorption of water and ammonia. The properties of the CPs can be traced back to the individual structural motifs and could thus trigger new design ideas for CPs in LIBs and/or catalysis.
KW - Alkaline earth metal coordination polymers
KW - Lithium-ion battery
KW - Water stability
KW - Fluorine coordination
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524041
DO - https://doi.org/10.1002/zaac.202000360
SN - 0044-2313
VL - 647
IS - 9
SP - 1014
EP - 1024
PB - Wiley-VCH GmbH
AN - OPUS4-52404
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Kulla, Hannes
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Reinholz, Uwe
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
T1 - Advances in Nickel Nanoparticle Synthesis via Oleylamine Route
N2 - Nickel nanoparticles are an active research area due to their multiple applications as catalysts in different processes. A variety of preparation techniques have been reported for the synthesis of these nanoparticles, including solvothermal, microwave-assisted, and emulsion techniques. The well-studied solvothermal oleylamine synthesis route comes with the drawback of needing standard air-free techniques and often space-consuming glassware. Here, we present a facile and straightforward synthesis method for size-controlled highly monodisperse nickel nanoparticles avoiding the use of, e.g., Schlenk techniques and space-consuming labware. The nanoparticles produced by this novel synthetic route were investigated using small-angle X-ray scattering, transmission electron microscopy, X-ray diffraction, and X-ray spectroscopy. The nanoparticles were in a size range of 4–16 nm, show high sphericity, no oxidation, and no agglomeration after synthesis.
KW - Nanoparticle synthesis
KW - Nickel nanoparticles
KW - SAXS
KW - TEM
KW - XAS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507531
DO - https://doi.org/10.3390/nano10040713
VL - 10
IS - 4
SP - 713
PB - MDPI
AN - OPUS4-50753
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chewle, Surahit
A1 - Emmerling, Franziska
A1 - Weber, M.
T1 - Effect of choice of solvent on crystallization pathway of paracetamol: An experimental and theoretical case study
N2 - The choice of solvents influences crystalline solid formed during the crystallization of active pharmaceutical ingredients (API). The underlying effects are not always well understood because of the complexity of the systems. Theoretical models are often insufficient to describe this phenomenon. In this study, the crystallization behavior of the model drug paracetamol in different solvents was studied based on experimental and molecular dynamics data. The crystallization process was followed in situ using time-resolved Raman spectroscopy. Molecular dynamics with simulated annealing algorithm was used for an atomistic understanding of the underlying processes. The experimental and theoretical data indicate that paracetamol molecules adopt a particular geometry in a given solvent predefining the crystallization of certain polymorphs
KW - Crystallization
KW - Nucleation
KW - Polymorphism
KW - Raman spectroscopy
KW - Cassical nucleation theory
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520052
DO - https://doi.org/10.3390/cryst10121107
SN - 2073-4352
VL - 10
IS - 12
SP - 1
EP - 10
PB - MDPI
CY - Basel
AN - OPUS4-52005
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, X.
A1 - Michalchuk, Adam
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Pulham, C.
T1 - High-pressure reversibility in a plastically flexible coordination polymer crystal
N2 - Single crystals which exhibit mechanical flexibility are promising materials for advanced technological applications. Before such materials can be used, a detailed understanding of the mechanisms of bending is needed. Using single crystal X-ray diffraction and microfocus Raman spectroscopy, we study in atomic detail the high-pressure response of the plastically flexible coordination polymer [Zn(μ-Cl)2(3,5-dichloropyridine)2]n (1). Contradictory to three-point bending, quasi-hydrostatic compression of (1) is completely reversible, even following compression to over 9 GPa. A structural phase transition is observed at ca. 5 GPa. DFT calculations show this transition to result from the pressure-induced softening of low-frequency vibrations. This phase transition is not observed during three-point-bending. Microfocus synchrotron X-ray diffraction revealed that bending yields significant mosaicity, as opposed to compression. Hence, our studies indicate of overall disparate mechanical responses of bulk flexibility and quasi-hydrostatic compression within the same crystal lattice. We suspect this to be a general feature of plastically bendable materials.
KW - High pressure
KW - Density functional theory
KW - Mechanically flexible crystals
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530360
DO - https://doi.org/10.1038/s41467-021-24165-x
VL - 12
IS - 1
SP - 3871
AN - OPUS4-53036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Gernhard, M.
A1 - Radnik, Jörg
A1 - Witt, Julia
A1 - Roth, C.
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis of fluorine-containing Co-doped zeolitic imidazolate frameworks for producing electrocatalysts
N2 - Catalysts derived from pyrolysis of metal organic frameworks (MOFs) are promising candidates to replace expensive and scarce platinum-based electrocatalysts commonly used in polymer electrolyte membrane fuel cells. MOFs contain ordered connections between metal centers and organic ligands. They can be pyrolyzed into metal- and nitrogen-doped carbons, which show electrocatalytic activity toward the oxygen reduction reaction (ORR). Furthermore, metal-free heteroatom-doped carbons, such as N-F-Cs, are known for being active as well. Thus, a carbon material with Co-N-F doping could possibly be even more promising as ORR electrocatalyst. Herein, we report the mechanochemical synthesis of two polymorphs of a zeolitic imidazole framework, Co-doped zinc 2-trifluoromethyl-1H-imidazolate (Zn0.9Co0.1(CF3-Im)2). Time-resolved in situ X-ray diffraction studies of the mechanochemical formation revealed a direct conversion of starting materials to the products. Both polymorphs of Zn0.9Co0.1(CF3-Im)2 were pyrolyzed, yielding Co-N-F containing carbons, which are active toward electrochemical ORR.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - Nobel-metal free electrocatalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546833
DO - https://doi.org/10.3389/fchem.2022.840758
SN - 2296-2646
VL - 10
IS - 840758
SP - 1
EP - 13
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, J.
A1 - Stawski, Tomasz
A1 - Smales, Glen Jacob
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
T1 - Towards automation of the polyol process for the synthesis of silver nanoparticles
N2 - Metal nanoparticles have a substantial impact across diferent felds of science, such as photochemistry, energy conversion, and medicine. Among the commonly used nanoparticles, silver nanoparticles are of special interest due to their antibacterial properties and applications in sensing and catalysis. However, many of the methods used to synthesize silver nanoparticles often do not result in well-defned products, the main obstacles being high polydispersity or a lack of particle size tunability. We describe an automated approach to on-demand synthesis of adjustable particles with mean radii of 3 and 5 nm using the polyol route. The polyol process is a promising route for silver nanoparticles e.g., to be used as reference materials. We characterised the as-synthesized nanoparticles using small-angle X-ray scattering, dynamic light scattering and further methods, showing that automated synthesis can yield colloids with reproducible and tuneable properties.
KW - Sillver
KW - Nanoparticles
KW - Automated synthesis
KW - Chemputer
KW - Scattering
KW - SAXS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546803
DO - https://doi.org/10.1038/s41598-022-09774-w
VL - 12
IS - 1
SP - 1
EP - 9
PB - Nature Springer
AN - OPUS4-54680
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zänker, Steffen
A1 - Scholz, G.
A1 - Marquardt, Julien
A1 - Emmerling, Franziska
T1 - Structural changes in Ba-compounds of different hardness induced by high-energy ball milling – evidenced by 137Ba NMR and X-ray powder diffraction
N2 - Changes in the global bulk and local structures, of three different barium compounds (BaZrO3, BaF2, and BaFCl),were induced by mechanical milling and followed using X-ray powder diffraction (PXRD), subsequent microstructure analysis, and 137Ba solid state NMR spectroscopy. Harder materials like BaZrO3 experience significantly higher structural changes upon milling than softer materials like BaF2. Moreover, soft materials with layered structures, like BaFCl, show a pronounced structural change during the milling process. By combining PXRD and solid state NMR, detailed information on the changes to the global and local structures were obtained, which are of interest for mechanochemical synthesis, mechanically treated catalysts or ionic conductors.
KW - Mechanochemistry
KW - X-ray diffraction
KW - Solid state NMR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547397
DO - https://doi.org/10.1002/zaac.202200026
SN - 0044-2313
VL - 648
IS - 10
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Accorsi, M.
A1 - Tiemann, M.
A1 - Wehrhan, L.
A1 - Finn, Lauren M.
A1 - Cruz, R.
A1 - Rautenberg, Max
A1 - Emmerling, Franziska
A1 - Heberle, J.
A1 - Keller, B. G.
A1 - Rademann, J.
T1 - Pentafluorophosphato-Phenylalanines: Amphiphilic Phosphotyrosine Mimetics Displaying Fluorine-Specific Protein Interactions
N2 - Phosphotyrosine residues are essential functional switches in health and disease. Thus, phosphotyrosine biomimetics are crucial for the development of chemical tools and drug molecules. We report here the discovery and investigation of pentafluorophosphato amino acids as novel phosphotyrosine biomimetics. A mild acidic pentafluorination protocol was developed and two PF5-amino acids were prepared and employed in peptide synthesis. Their structures, reactivities, and fluorine-specific interactions were studied by NMR and IR spectroscopy, X-ray diffraction, and in bioactivity assays. The mono-anionic PF5 motif displayed an amphiphilic character binding to hydrophobic surfaces, to water molecules, and to protein-binding sites, exploiting charge and H−F-bonding interactions. The novel motifs bind 25- to 30-fold stronger to the phosphotyrosine binding site of the protein tyrosine phosphatase PTP1B than the best current biomimetics, as rationalized by computational methods, including molecular dynamics simulations.
KW - Chemical Biology
KW - Drug Development
KW - Pentafluorophosphates
KW - Phosphotyrosine Biomimetics
KW - Protein Tyrosine Phosphatases
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549984
DO - https://doi.org/10.1002/anie.202203579
SN - 1433-7851
VL - 134
IS - 25
SP - 1
EP - 6
PB - Wiley-VCH GmbH
AN - OPUS4-54998
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Belenguer, A.
A1 - Lampronti, G.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
A1 - Sanders, J.
T1 - Quantitative reversible one pot interconversion of three crystalline polymorphs by ball mill grinding
N2 - We demonstrate here using a disulfide system the first example of reversible, selective, and quantitative transformation between three crystalline polymorphs by ball mill grinding. This includes the discovery of a previously unknown polymorph. Each polymorph is reproducibly obtained under well-defined neat or liquid-assisted grinding conditions, revealing subtle control over the apparent thermodynamic stability. We discovered that the presence of a contaminant as low as 1.5% mol mol−1 acting as a template is required to enable all these three polymorph transformations. The relative stabilities of the polymorphs are determined by the sizes of the nanocrystals produced under different conditions and by surface interactions with small amounts of added solvent. For the first time, we show evidence that each of the three polymorphs is obtained with a unique and reproducible crystalline size. This mechanochemical approach gives access to bulk quantities of metastable polymorphs that are inaccessible through recrystallisation.
KW - Mechanochemistry
KW - Polymorph
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549934
DO - https://doi.org/10.1039/D2CE00393G
SP - 1
EP - 7
PB - Royal Society of Chemistry
AN - OPUS4-54993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Heinekamp, Christian
A1 - Smales, Glen Jacob
A1 - Hodoroaba, Vasile-Dan
A1 - ten Elshof, J. E.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz
T1 - Template-free synthesis of mesoporous, amorphous transition metal phosphate materials
N2 - We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves a transformation of a precursor metal phosphate phase, called M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, NixCo1-x2+). It relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneously mesoporous phase, which forms while degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the metal coordination environment were followed with in-situ and ex-situ scattering and diffraction, as well as X -ray spectroscopy. Despite sharing the same precursor struvite structure, different amorphous and mesoporous structures were obtained depending on the involved transition metal. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions depending on a metal cation present in the analogous M-struvites. The amorphous structures of thermally decomposed Mg-, Ni- and NixCo1-x-struvites exhibit high surface areas and pore volumes (240 m²g-1 and 0.32 cm-3 g-1 for Mg and 90 m²g-1 and 0.13 cm-3 g-1 for Ni). We propose that the low-cost, environmentally friendly M-struvites could be obtained as recycling products from industrial and agricultural wastewaters. These waste products could be then upcycled into mesoporous TMPs through a simple thermal treatment for further applications, for instance, in (electro)catalysis.
KW - Struvite
KW - Pphosphates
KW - Transition metal
KW - In-situ SAXS/WAXS
KW - Mesoporosity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569503
DO - https://doi.org/10.1039/D2NR05630E
SN - 2040-3364
SP - 1
EP - 15
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-56950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Bhattacharya, Biswajit
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Fink, Friedrich
A1 - Feldmann, Ines
A1 - ten Elshof, J. E.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz
T1 - Thermally processed Ni-and Co-struvites as functional materials for proton conductivity
N2 - We present how mesoporosity can be engineered in transition metal phosphate (TMPs) materials in a template-free manner. The method involves the transformation of a precursor metal phosphate phase, called M-struvite (NH4MPO4·6H2O, M = Mg2+, Ni2+, Co2+, NixCo1−x2+). It relies on the thermal decomposition of crystalline M-struvite precursors to an amorphous and simultaneously mesoporous phase, which forms during degassing of NH3 and H2O. The temporal evolution of mesoporous frameworks and the response of the metal coordination environment were followed by in situ and ex situ scattering and diffraction, as well as X-ray spectroscopy. Despite sharing the same precursor struvite structure, different amorphous and mesoporous structures were obtained depending on the involved transition metal. We highlight the systematic differences in absolute surface area, pore shape, pore size, and phase transitions depending on the metal cation present in the analogous M-struvites. The amorphous structures of thermally decomposed Mg-, Ni- and NixCo1−x-struvites exhibit high surface areas and pore volumes (240 m2 g−1 and 0.32 cm−3 g−1 for Mg and 90 m2 g−1 and 0.13 cm−3 g−1 for Ni). We propose that the low-cost, environmentally friendly M-struvites could be obtained as recycling products from industrial and agricultural wastewaters. These waste products could be then upcycled into mesoporous TMPs through a simple thermal treatment for further application, for instance in (electro)catalysis.
KW - Struvite
KW - Phosphates
KW - Transition metals
KW - Proton conductivity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575862
DO - https://doi.org/10.1039/D3DT00839H
SN - 1477-9226
SP - 1
EP - 13
PB - Royal Society of Chemisty (RSC)
CY - London/Cambridge
AN - OPUS4-57586
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Ryll, T. W.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz Maciej
T1 - Phase stability studies on transition metal phosphates aided by an automated synthesis
N2 - Transition metal phosphates (TMPs) have attracted interest as materials for (electro-) catalysis, and electrochemistry due to their low-cost, stability, and tunability. In this work, an automated synthesis platform was used for the preparation of transition metal phosphate crystals to efficiently explore the multidimensional parameter space, determining the phase selection, crystal sizes, shapes. By using X-ray diffraction and spectroscopy-based methods and electron microscopy imaging, a complete characterization of the phase stability fields, phase transitions, and crystal morphology/sizes was achieved. In an automated three-reactant synthesis, the individual effect of each reactant species NH4+, M2+, and PO43- on the formation of transition metal phosphate phases: M-struvite NH4MPO4·6H2O, M-phosphate octahydrate M3(PO4)2·8H2O with M = Ni, Co and an amorphous phase, was investigated. The NH4+ concentration dictates the phase composition, morphology, and particle size in the Ni-system (crystalline Ni-struvite versus amorphous Ni-PO4 phase), whereas in the Co-system all reactant species - NH4+, Co2+, and PO43- - influence the reaction outcome equivalently (Co-struvite vs. Co-phosphate octahydrate). The coordination environment for all crystalline compounds and of the amorphous Ni-PO4 phase was resolved by X-ray absorption spectroscopy, revealing matching characteristics to its crystalline analogue, Ni3(PO4)2·8H2O. The automated synthesis turned out to be significantly advantageous for the exploration of phase diagrams due to its simple modularity, facile traceability, and enhanced reproducibility compared to a typical manual synthesis.
KW - Automated synthesis
KW - Phase diagrams
KW - Transition metals
KW - Phosphates
KW - Local structure
KW - Struvite
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579151
DO - https://doi.org/10.1039/D3CE00386H
VL - 25
IS - 30
SP - 4333
EP - 4344
PB - CrystEngComm
CY - London
AN - OPUS4-57915
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Akhmetova, Irina
A1 - Das, Chayanika
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Synthesis and In Situ Monitoring of Mechanochemical Preparation of Highly Proton Conductive Hydrogen-Bonded Metal Phosphonates
N2 - Crystalline porous materials are recognized as promising proton conductors for the proton exchange membrane (PEM) in fuel cell technology owing to their tunable framework structure. However, it is still a challenging bulk synthesis for real-world applications of these materials. Herein, we report the mechanochemical gram-scale synthesis of two isostructural metal hydrogen-bonded organic frameworks (MHOFs) of Co(II) and Ni(II) based on 1-hydroxyethylidenediphosphonic acid (HEDPH4) with 2,2′-bipyridine (2,2′-bipy): Co(HEDPH3)2(2,2′-bipy)·H2O (1) and Ni(HEDPH3)2(2,2′-bipy)·H2O (2). In situ monitoring of the mechanochemical synthesis using different synchrotron-based techniques revealed a one-step mechanism – the starting materials are directly converted to the product. With the existence of extensive hydrogen bonds with amphiprotic uncoordinated phosphonate hydroxyl and oxygen atoms, both frameworks exhibited proton conduction in the range of 10–4 S cm–1 at room temperature under humid conditions. This study demonstrates the potential of green mechanosynthesis for bulk material preparation of framework-based solid-state proton conductors.
KW - Mechanochemistry
KW - Proton conductivity
KW - Metal Organic Frameworks
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577777
DO - https://doi.org/10.1021/acssuschemeng.2c07509
VL - 8
IS - 19
SP - 16687
EP - 16693
PB - ACS Publications
AN - OPUS4-57777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bui, M.
A1 - Hoffmann, K. F.
A1 - Braun, T.
A1 - Riedel, S.
A1 - Heinekamp, Christian
A1 - Scheurell, K.
A1 - Scholz, G.
A1 - Stawski, Tomasz
A1 - Emmerling, Franziska
T1 - An Amorphous Teflate Doped Aluminium Chlorofluoride:
A Solid Lewis-Superacid for the Dehydrofluorination of
Fluoroalkanes
N2 - Ananion-dopedaluminiumchlorofluoride AlCl0.1F2.8(OTeF5)0.1(ACF-teflate) was synthesized.The material contains pentafluor-oorthotellurate(teflate)groups, which mimic fluoride ions electronically, but are sterically more demanding. They are embedded into the amorphous structure. The latter was studied by PDF analysis, EXAFS data and MAS NMR spectroscopy. The mesoporous powder is a Lewis superacid, and ATR-IR spectra of adsorbed CD3CN reveal a blue-shift of the adsorption band by73 cm-1, which is larger than the shift for SbF5. Remarkably,ACF-teflate catalyzes dehydrofluorination reactions of mono-fluoroalkanes to yield olefins in C6D6. In these cases,no Friedel-Crafts products were formed.
KW - Aluminium fluorides
KW - Aluminium teflates
KW - C-F bond activation
KW - Lewis superacids
KW - Silanes
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572290
DO - https://doi.org/10.1002/cctc.202300350
SN - 1867-3880
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-57229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Goedecke, Caroline
A1 - Bannick, C.-G.
A1 - Abusafia, A.
A1 - Scheid, C.
A1 - Steinmetz, H.
A1 - Paul, Andrea
A1 - Beleites, C.
A1 - Braun, U.
T1 - Identification of microplastic pathways within a typical European urban wastewater system
N2 - In recent years, thermoextraction/desorption-gas chromatography/mass spectrometry (TED-GC/MS) has been developed as a rapid detection method for the determination of microplastics (MP) mass contents in numerous environmentally relevant matrices and, in particular, for the measurement of polymers in water samples without time-consuming sample preparation. The TED-GC/MS method was applied to investigate a typical European municipal wastewater system for possible MP masses. Such investigations are important in view of the recent revision of the Urban Wastewater Treatment Directive. Four different representative sampling sites were selected: greywater (domestic wastewater without toilet), combined sewer, and influent and effluent of a wastewater treatment plant (WWTP). All samples were collected by fractional filtration. Filtration was carried out over mesh sizes of 500, 100, 50, and in some cases, 5 µm. Polyethylene (PE), polypropylene (PP), and polystyrene (PS) were detected in all samples, with the PE fraction dominating in all cases. Styrene-butadiene rubber which serves as an indication of tire abrasion, was only found in the influent of the WWTP. The highest MP mass contents were found in the combined sewer, so MP can become a source of pollution during heavy rain events when the capacity limits of the effluent are reached, and the polluted effluent is released uncontrolled into the environment. Based on the studies, MP retention from the WWTP could be estimated to be approximately 96%. Few trends in polymer type or mass contents were detected within the different fractions of the samples or when comparing samples to each other.
KW - Microplastics
KW - Microplastic analysis
KW - TED-GC/MS
KW - Microplastic pathways
KW - Mass contents
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568289
DO - https://doi.org/doi.org/10.1002/appl.202200078
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ahrens, M.
A1 - Braun, T.
A1 - Emmerling, Franziska
T1 - An amorphous Lewis-acidic zirconium chlorofluoride as HF shuttle: C–F bond activation and formation
N2 - An exceptional HF transfer reaction by C–F bond activation of fluoropentane and a subsequent hydrofluorination of alkynes at room temperature is reported. An amorphous Lewis-acidic Zr chlorofluoride serves as heterogeneous catalyst, which is characterised by an eightfold coordination environment at Zr including chlorine atoms. The studies are seminal in establishing sustainable fluorine chemistry.
KW - ZCF
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - HF-shuttle
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582249
DO - https://doi.org/10.1039/D3CC03164K
SN - 1359-7345
VL - 59
IS - 75
SP - 11224
EP - 11227
PB - RSC
CY - Cambridge
AN - OPUS4-58224
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oksal-Kilinc, Sefine
A1 - Altmann, Korinna
A1 - Seiwert, Bettina
A1 - Reemtsma, Thorsten
A1 - Ruess, Liliane
T1 - Grinding method and oxidative aging modulate the impact of tire wear microplastics on the reproduction of the nematode C. elegans
N2 - Rationale Tire abrasion is one of the largest sources of microplastic in aquatic and terrestrial environments. Despite this fact, research on tire wear microplastic (TWP) and its effects on soil ecosystems is scarce, especially regarding natural weathering processes. This leaves a large knowledge gap on the interactions of TWP with soil biota. Methodology Cryo-milled tire tread (CMTT) and diamond-ground tire tread (DGTT) were artificially weathered through dry ozone treatment and heat exposure. Particles were analyzed via scanning electron microscopy, particle size distribution, and shape characterization. TWP leachate composition was examined using liquid chromatography–mass spectrometry. The impact on the reproduction of the nematode Caenorhabditis elegans, a widely used toxicological model, was tested for leachate concentration, exposure duration and TWP aging status, using offspring per adult as the endpoint. Results The comminution method significantly influenced TWP particle size distribution, with diamond grinding yielding smaller particles and a more structured surface morphology than cryo-milling. Aging with ozone (180 min) and heat (20 min at 100 °C) reduced DGTT particle sizes by 27-58%, but not in CMTT. Additionally, aging increased carboxylic functional groups and led to a brittle structure in both TWP types. Leachate composition varied with comminution method and aging. Benzothiazole, N-Cyclo-N-phenylurea, and aniline were more abundant in pristine and aged CMTT and aged DGTT. Diphenylguanidine had the highest concentration in all leachates. Aged TWP leachates, regardless of comminution, had significant toxic effects on C. elegans. Leachate from pristine CMTT was more toxic than from pristine DGTT. Nematode offspring correlated negatively with ozone exposure duration in aged DGTT. Tests with aged CMTT leachate showed even short-term exposure reduced offspring numbers. Discussion The results underscore the importance of oxidative and mechanical weathering in TWP toxicity and challenge the use of pristine particles in toxicological assays for risk assessment in the natural environment.
KW - Microplastics
KW - Tire abrasion
KW - Environment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654672
DO - https://doi.org/10.1071/EN25051
SN - 1448-2517
VL - 23
IS - 2
SP - 1
EP - 16
PB - CSIRO Publishing
AN - OPUS4-65467
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
T1 - The Mechanochemical Excitation of Crystalline LiN3
N2 - Mechanochemical reactions are driven by the direct absorption of mechanical energy by a solid (often crystalline) material. Understanding how this energy is absorbed and ultimately causes a chemical transformation is essential for understanding the elementary stages of mechanochemical transformations. Using as a model system the energetic material LiN3 we here consider how vibrational energy flows through the crystal structure. By considering the compression response of the crystalline material we identify the partitioning of energy into an initial vibrational excitation. Subsequent energy flow is based on concepts of phonon–phonon scattering, which we calculate within a quasi-equilibrium model facilitated by phonon scattering data obtained from Density Functional Theory (DFT). Using this model we demonstrate how the moments (picoseconds) immediately following mechanical impact lead to significant thermal excitation of crystalline LiN3, sufficient to drive marked changes in its electronic structure and hence chemical reactivity. This work paves the way towards an ab initio approach to studying elementary processes in mechanochemical reactions involving crystalline solids.
KW - Energetic materials
KW - Ab initio simulation
KW - DFT
KW - Mechanochemistry
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559310
DO - https://doi.org/10.1039/d2fd00112h
SP - 1
EP - 20
PB - Royal Society of Chemistry
AN - OPUS4-55931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Cakir, Cafer Tufan
A1 - Radtke, Martin
A1 - Haider, M. Bilal
A1 - Emmerling, Franziska
A1 - F. M. Oliveira, P.
A1 - Michalchuk, Adam
T1 - Dispersive x-ray absorption spectroscopy for time-resolved in situ monitoring of mechanochemical reactions
N2 - X-ray absorption spectroscopy (XAS) provides a unique, atom-specific tool to probe the electronic structure of solids. By surmounting long-held limitations of powder-based XAS using a dynamically averaged powder in a Resonant Acoustic Mixer (RAM), we demonstrate how time-resolved in situ (TRIS) XAS provides unprecedented detail of mechanochemical synthesis. The use of a custom-designed dispersive XAS (DXAS) setup allows us to increase the time resolution over existing fluorescence measurements from ∼15 min to 2 s for a complete absorption spectrum. Hence, we here establish TRIS-XAS as a viable method for studying mechanochemical reactions and sampling reaction kinetics. The generality of our approach is demonstrated through RAM-induced (i) bottom-up Au nanoparticle mechanosynthesis and (ii) the synthesis of a prototypical metal organic framework, ZIF-8. Moreover, we demonstrate that our approach also works with the addition of a stainless steel milling ball, opening the door to using TRIS-DXAS for following conventional ball milling reactions. We expect that our TRIS-DXAS approach will become an essential part of the mechanochemical tool box.
KW - In situ studies
KW - Dipsersive XAS
KW - Mechanochemistry
KW - Time-resolved
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567659
DO - https://doi.org/10.1063/5.0130673
SN - 1089-7690
VL - 157
IS - 21
SP - 1
EP - 12
PB - American Institute of Physics
CY - Melville, NY
AN - OPUS4-56765
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ravi, J.
A1 - Feiler, Torvid
A1 - Mondal, A.
A1 - Michalchuk, Adam
A1 - Reddy, C. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Chandrasekar, R.
T1 - Plastically bendable organic crystals for monolithic and hybrid micro-optical circuits
N2 - Fluorescent plastically bendable crystals are a promising alternative to silicon-based materials for fabricating photonic integrated circuits, owing to their optical attributes and mechanical compliance. Mechanically bendable plastic organic crystals are rare. Their formation requires anisotropic intermolecular interactions and slip planes in the crystal lattice. This work presents three fluorescent plastically bendable crystalline materials namely, 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-chlorophenol (SB1), 2-((E)-(6-methylpyridin-2-ylimino)methyl)-4-bromophenol (SB2), and 2-((E)-(6-Bromopyridin-2-ylimino)methyl)-4-bromophenol (SB3) molecules. The crystal plasticity in response to mechanical stress facilitates the fabrication of various monolithic and hybrid (with a tip-to-tip coupling) photonic circuits using mechanical micromanipulation with an atomic force microscope cantilever tip. These plastically bendable crystals act as active (self-guiding of fluorescence) and passive waveguides both in straight and extremely bent (U-, J-, and O-shaped) geometries. These microcircuits use active and passive waveguiding principles and reabsorbance and energy-transfer mechanisms for their operation, allowing input-selective and direction-specific signal transduction.
KW - Flexible crystals
KW - Flexible waveguide
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565302
DO - https://doi.org/10.1002/adom.202201518
SN - 2195-1071
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56530
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Silbernagl, Dorothee
A1 - Yasuda, N.
A1 - Feiler, Torvid
A1 - Sturm, Heinz
A1 - Emmerling, Franziska
T1 - An atomistic mechanism for elasto-plastic bending in molecular crystals
N2 - Mechanically flexible single crystals of molecular materials offer potential for a multitude of new directions in advanced materials design. Before the full potential of such materials can be exploited, insight into their mechanisms of action must be better understood. Such insight can be only obtained through synergistic use of advanced experimentation and simulation. We herein report the first detailed mechanistic study of elasto-plastic flexibility in a molecular solid. An atomistic origin for this mechanical behaviour is proposed through a combination of atomic force microscopy, μ-focus synchrotron X-ray diffraction, Raman spectroscopy, ab initio simulation, and computed elastic tensors. Our findings suggest that elastic and plastic bending are intimately linked and result from extensions of the same molecular deformations. The proposed mechanism bridges the gap between contested mechanisms, suggesting its applicability as a general mechanism for elastic and plastic bending in organic molecular crystals.
KW - Mechanical property
KW - Mechanical flexibility
KW - Organic crystal
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577722
DO - https://doi.org/10.1039/D2SC06470G
SN - 2041-6520
VL - 14
IS - 13
SP - 3441
EP - 3450
PB - Royal Society of Chemisty (RSC)
CY - London/Cambridge
AN - OPUS4-57772
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Yasuda, N.
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Mechanistic Investigation of an Elastically Flexible Organic Crystal
N2 - Mechanical flexibility in molecular crystals is a fascinating behavior with potential for developing advanced technologies. However, the phenomenon of mechanical bending is poorly understood. We explore for the first time the atomistic origin of elastic bending in a single component organic crystal using a combination of μ-focus synchrotron X-ray diffraction and ab initio simulation.
KW - Flexible crystals
KW - DFT calculation
KW - Bending mechanism
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581949
DO - https://doi.org/10.1021/acs.cgd.3c00473
SN - 1528-7483
VL - 23
IS - 9
SP - 6244
EP - 6249
PB - ACS Publications
AN - OPUS4-58194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Unintended Rate Enhancement in Mechanochemical Kinetics by Using Poly(methyl methacrylate) Jars
N2 - Time-resolved in situ (TRIS) X-ray diffraction has changed how mechanochemical transformations are studied but requires the use of X-ray transparent jars often made from poly(methyl methacrylate) (PMMA). However, using PMMA jars can alter the apparent kinetics of mechanochemical polymorphism by an order of magnitude, questioning the interpretability of established TRIS methods. Our results suggest that rate enhancement in PMMA jars may not be dominated by chemical effects of the polymer, but rather a result of different equilibrium temperatures within the jar. These features must be better understood before control over mechanochemical reactions can be achieved.
KW - Mechanochemistry
KW - Organic compounds
KW - Polymers
KW - Materials
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565276
DO - https://doi.org/10.1021/acs.cgd.2c01227
SN - 1528-7483
SP - 1
EP - 5
PB - ACS Publications
AN - OPUS4-56527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuhlich, Paul
A1 - Emmerling, Franziska
A1 - Kraus, Werner
A1 - Nehls, Irene
A1 - Piechotta, Christian
T1 - 1-(4-bromo-3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalen-2-yl)ethan-1-one: a precursor for phase-I metabolite of AHTN
N2 - The title compound, C18H25BrO, crystallized as a racemate with four independent molecules in the asymmetric unit. In the crystal, three of these four molecules are linked via C-Br...Br-C halogen bonds [Br...Br = 3.662 (2) and 3.652 (2) Å], forming dimers.
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-279935
DO - https://doi.org/10.1107/S1600536813006934
SN - 1600-5368
VL - 69
IS - 4
SP - o545, sup-1
EP - sup-17
PB - Munksgaard
CY - Copenhagen
AN - OPUS4-27993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merkel, Stefan
A1 - Köppen, Robert
A1 - Koch, Matthias
A1 - Emmerling, Franziska
A1 - Nehls, Irene
T1 - Ergotaminine
N2 - The title compound {systematic name: (6aR,9S)-N-[(2R,5S,10aS,10bS)-5-benzyl-10b-hydroxy-2-methyl-3,6-dioxooctahydro-8H-oxazolo[3,2-a]pyrrolo[2,1-c]pyrazin-2-yl]-7-methyl-4,6,6a,7,8,9-hexahydroindolo[4,3-fg]quinoline-9-carboxamide}, C33H35N5O5, was formed by an epimerization reaction of ergotamine. The non-aromatic ring (ring C of the ergoline skeleton) directly fused to the aromatic rings is nearly planar [maximum deviation = 0.317 (4) Å] and shows an envelope conformation, whereas ring D, involved in an intramolecular N–H···N hydrogen bond exhibits a slightly distorted chair conformation. The structure displays chains running approximately parallel to the diagonal of bc plane that are formed through N–H···O hydrogen bonds.
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-254528
DO - https://doi.org/10.1107/S1600536812003674
SN - 1600-5368
VL - 68
IS - 3
SP - o610-o611, sup1-sup11
PB - Munksgaard
CY - Copenhagen
AN - OPUS4-25452
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kuhlich, Paul
A1 - Emmerling, Franziska
A1 - Piechotta, Christian
A1 - Nehls, Irene
T1 - Methyl 3,5,5,6,8,8-hexamethyl-5,6,7,8-tetrahydronaphthalene-2-carboxylate (AHTN-COOMe)
N2 - Crystals of the title compound, C18H26O2, were grown from ethyl acetate. Due to the racemic precursor, the title compound is also obtained as a racemate. Disorder was observed during structure refinement, originating from two possible half-chair conformations of the non-aromatic ring. The disorder was refined by introducing split positions in the cyclo-hexane ring regarding the two possible R and S-enantiomers at the chiral CH group [ratio 0.744 (3):0.256 (3)]. The crystal structure features pairs of inversion-related molecules connected by pairs of non-classical C–H···O hydrogen bonds.
KW - AHTN
KW - Tonalide
KW - Cyclic musk
KW - AHTN-COOMe
KW - Disinfection by-product
KW - Esterification
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-232769
DO - https://doi.org/10.1107/S1600536811002601
SN - 1600-5368
VL - E67
IS - 2
SP - o485, sup-1
EP - sup-11
PB - Munksgaard
CY - Copenhagen
AN - OPUS4-23276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Batzdorf, Lisa
A1 - Wilke, Manuel
A1 - Szczerba, Wojciech
A1 - Reinholz, Uwe
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis and characterisation of two new bismuth metal organic frameworks
N2 - Two metal organic structures composed of the ligands benzene-1,4-dicarboxylate and pyridine-2,5-dicarboxylate and bismuth cations are presented: (H2Im)[Bi(1,4-bdc)2] (1) and [Bi(pydc)(NO3)2(H2O)2]*H2O (2) (bdc = benzenedicarboxylate, H2Im = imidazole cation, pydc = pyridinedicarboxylate). Both compounds were synthesised via grinding and the crystal structure of compound (2) was solved based on its powder diffraction pattern. Compound 1 crystallises isostructurally to the dimethyl ammonium containing compound (dma)[(Bi(1,4-bdc)2]. Raman spectroscopy and Extended X-ray absorption fine structure (EXAFS)
measurements provided additional information about the two mechanochemically synthesised metal organic compounds.
KW - Crystal structure
KW - Mechanochemically synthesis
KW - Powder diffraction measurements
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-306296
DO - https://doi.org/10.1039/C3CE42633E
SN - 1466-8033
N1 - Geburtsname von Batzdorf, Lisa: Tröbs, L. - Birth name of Batzdorf, Lisa: Tröbs, L.
VL - 16
IS - 25
SP - 5560
EP - 5565
CY - London, UK
AN - OPUS4-30629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merkel, Stefan
A1 - Köppen, Robert
A1 - Koch, Matthias
A1 - Emmerling, Franziska
A1 - Nehls, Irene
T1 - Lysergol monohydrate
N2 - In the title compound [systematic name: (7-methyl-4,6,6a,7,8,9-hexahydroindolo[4,3,2-fg]quinoline-9-yl)methanol monohydrate], C16H18N2O·H2O, the non-aromatic ring (ring C of the ergoline skeleton) directly fused to the aromatic rings is nearly planar, with a maximum deviation of 0.659 (3) Å, and shows an envelope conformation. In the crystal, hydrogen bonds between the lysergol and water molecules contribute to the formation of layers parallel to (10-2).
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-254015
DO - https://doi.org/10.1107/S1600536812002632
SN - 1600-5368
VL - 68
IS - 2
SP - o523, sup1
EP - sup8
PB - Munksgaard
CY - Copenhagen
AN - OPUS4-25401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Batzdorf, Lisa
A1 - Emmerling, Franziska
T1 - Mechanochemical synthesis and characterisation of cocrystals and metal-organic compounds
N2 - The mechanochemical synthesis of two model compounds, a metal organic framework ([Bi(1,4-bdc)2]*(Im) (bdc = benzene dicarboxylate, Im = imidazole cation)) and a cocrystal (Carbamazepine:Indometacin 1:1) were followed ex situ by combined analytical methods. Powder X-ray diffraction (XRD) and Raman spectroscopy data were evaluated for the synthesis of the metal organic framework. XRD measurements and REM images were analysed for the synthesis of the cocrystal. The measurements revealed that both model compounds were synthesised within minutes. The metal organic framework [Bi(1,4-bdc)2]*(Im) is synthesised via an intermediate structure. The cocrystal Carbamazepine:Indometacin 1:1 is formed within few seconds and afterwards the crystallite size decreases extremely.
KW - Powder X-ray diffraction (XRD)
KW - Raman spectroscopy
KW - mechanochemical synthesis
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-306305
UR - http://pubs.rsc.org/en/content/articlepdf/2014/fd/c3fd00163f
DO - https://doi.org/10.1039/C3FD00163F
SN - 1359-6640
SN - 1364-5498
N1 - Geburtsname von Batzdorf, Lisa: Tröbs, L. - Birth name of Batzdorf, Lisa: Tröbs, L.
SP - 109
EP - 119
PB - RSC
CY - Cambridge [u.a.]
AN - OPUS4-30630
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbas, Ioana M.
A1 - Schwaar, Timm
A1 - Bienwald, Frank
A1 - Weller, Michael G.
T1 - Predictable Peptide Conjugation Ratios by Activation of Proteins with Succinimidyl Iodoacetate (SIA)
N2 - The small heterobifunctional linker succinimidyl iodoacetate (SIA) was examined for the preparation of peptide–protein bioconjugates with predicable conjugation ratios. For many conjugation protocols, the protein is either treated with a reductant to cleave disulfide bonds or is reacted with thiolation chemicals, such as Traut’s reagent. Both approaches are difficult to control, need individual optimization and often lead to unsatisfactory results. In another popular approach, a heterobifunctional linker with a N-hydroxysuccinimide (NHS) and a maleimide functionality is applied to the protein. After the activation of some lysine ε-amino groups with the NHS ester functionality, a cysteine-containing peptide is attached to the activated carrier protein via maleimide. Particularly, the maleimide reaction leads to some unwanted byproducts or even cleavage of the linker. Many protocols end up with conjugates with unpredictable and irreproducible conjugation ratios. In addition, the maleimide-thiol addition product should be assumed immunogenic in vivo. To avoid these and other disadvantages of the maleimide approach, we examined the known linker succinimidyl iodoacetate (SIA) in more detail and developed two protocols, which lead to peptide–protein conjugates with predefined average conjugation ratios. This holds potential to eliminate tedious and expensive optimization steps for the synthesis of a bioconjugate of optimal composition.
KW - Bioconjugate
KW - Carrier protein
KW - Immunogen
KW - Hapten
KW - Linker
KW - Antibody drug conjugate
KW - ADC
KW - Drug-to-antibody ratio
KW - DAR
KW - Conjugation ratio
KW - Conjugation density
KW - Carrier load
KW - Click reaction
KW - Click chemistry
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427188
UR - http://www.mdpi.com/2409-9279/1/1/2
DO - https://doi.org/10.3390/mps1010002
SN - 2409-9279
VL - 1
SP - 1
EP - 14
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-42718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steglich, P.
A1 - Bondarenko, S.
A1 - Mai, C.
A1 - Paul, Martin
A1 - Weller, Michael G.
A1 - Mai, A.
T1 - CMOS-Compatible Silicon Photonic Sensor for Refractive Index Sensing Using Local Back-Side Release
N2 - Silicon photonic sensors are promising candidates for lab-on-a-chip solutions with versatile applications and scalable production prospects using complementary metal-oxide semiconductor (CMOS) fabrication methods. However, the widespread use has been hindered because the sensing area adjoins optical and electrical components making packaging and sensor handling challenging. In this work, a local back-side release of the photonic sensor is employed, enabling a separation of the sensing area from the rest of the chip. This approach allows preserving the compatibility of photonic integrated circuits in the front-end of line and metal interconnects in the back-end of line. The sensor is based on a micro-ring resonator and is fabricated on wafer-level using a CMOS technology. We revealed a ring resonator sensitivity for homogeneous sensing of 106 nm/RIU.
KW - Photonic biosensor
KW - Lab-on-a-chip
KW - Ring resonator
KW - Resonance wavelength shift
KW - PIC technology
KW - Back-side integration
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517139
DO - https://doi.org/10.1109/LPT.2020.3019114
VL - 32
IS - 19
SP - 1241
EP - 1244
PB - IEEE
AN - OPUS4-51713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weller, Michael G.
T1 - Ten Basic Rules of Antibody Validation
N2 - The quality of research antibodies is an issue for decades. Although several papers have been published to improve the situation, their impact seems to be limited. This publication makes the effort to simplify the description of validation criteria in a way that the occasional antibody user is able to assess the validation level of an immunochemical reagent. A simple, 1-page checklist is supplied for the practical application of these criteria.
KW - Replication
KW - Reproducibility
KW - Documentation
KW - Open Science
KW - Quality Control
KW - Biochemistry
KW - Biotechnology
KW - Bioanalysis
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-444322
UR - https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5813849/
DO - https://doi.org/10.1177/1177390118757462
SN - 11773901
VL - 13
SP - 1
EP - 5
PB - Sage
CY - Los Angeles, USA
AN - OPUS4-44432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tscheuschner, Georg
A1 - Kaiser, Melanie N.
A1 - Lisec, Jan
A1 - Beslic, D.
A1 - Muth, Thilo
A1 - Krüger, M.
A1 - Mages, H. W.
A1 - Dorner, B. G.
A1 - Knospe, J.
A1 - Schenk, J. A.
A1 - Sellrie, F.
A1 - Weller, Michael G.
T1 - MALDI-TOF-MS-Based Identification of Monoclonal Murine Anti-SARS-CoV-2 Antibodies within One Hour
N2 - During the SARS-CoV-2 pandemic, many virus-binding monoclonal antibodies have been developed for clinical and diagnostic purposes. This underlines the importance of antibodies as universal bioanalytical reagents. However, little attention is given to the reproducibility crisis that scientific studies are still facing to date. In a recent study, not even half of all research antibodies mentioned in publications could be identified at all. This should spark more efforts in the search for practical solutions for the traceability of antibodies. For this purpose, we used 35 monoclonal antibodies against SARS-CoV-2 to demonstrate how sequence-independent antibody identification can be achieved by simple means applied to the protein. First, we examined the intact and light chain masses of the antibodies relative to the reference material NIST-mAb 8671. Already half of the antibodies could be identified based solely on these two parameters. In addition, we developed two complementary peptide mass fingerprinting methods with MALDI-TOF-MS that can be performed in 60 min and had a combined sequence coverage of over 80%. One method is based on the partial acidic hydrolysis of the protein by 5 mM of sulfuric acid at 99 degrees C. Furthermore, we established a fast way for a tryptic digest without an alkylation step. We were able to show that the distinction of clones is possible simply by a brief visual comparison of the mass spectra. In this work, two clones originating from the same immunization gave the same fingerprints. Later, a hybridoma sequencing confirmed the sequence identity of these sister clones. In order to automate the spectral comparison for larger libraries of antibodies, we developed the online software ABID 2.0. This open-source software determines the number of matching peptides in the fingerprint spectra. We propose that publications and other documents critically relying on monoclonal antibodies with unknown amino acid sequences should include at least one antibody fingerprint. By fingerprinting an antibody in question, its identity can be confirmed by comparison with a library spectrum at any time and context.
KW - Reproducibility
KW - Quality control
KW - Traceability
KW - Peptides
KW - Peptide mass fingerprinting
KW - Monoclonal antibody
KW - Recombinant antibody
KW - Identity
KW - Antibody identification
KW - Sequencing
KW - Light chain
KW - Mass spectrometry
KW - Software
KW - Open science
KW - Library
KW - COVID-19
KW - Corona virus
KW - Sequence coverage
KW - NIST-mAb 8671
KW - Reference material
KW - RBD
KW - Spike protein
KW - Nucleocapsid
KW - Cleavage
KW - Tryptic digest
KW - MALDI
KW - DHAP
KW - 2,5-dihydroxyacetophenone
KW - Github
KW - Zenodo
KW - ABID
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547347
DO - https://doi.org/10.3390/antib11020027
VL - 11
IS - 2
SP - 1
EP - 22
PB - MDPI
CY - Basel
AN - OPUS4-54734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kader, A.
A1 - Brangsch, J.
A1 - Reimann, C.
A1 - Kaufmann, Jan Ole
A1 - Mangarova, D. B.
A1 - Moeckel, J.
A1 - Adams, L. C.
A1 - Zhao, J.
A1 - Saatz, Jessica
A1 - Traub, Heike
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Visualization and Quantification of the Extracellular Matrix in Prostate Cancer Using an Elastin Specific Molecular Probe
N2 - One of the most commonly diagnosed cancers in men is prostate cancer (PCa). Understanding tumor progression can help diagnose and treat the disease at an early stage. Components of the extracellular matrix (ECM) play a key role in the development and progression of PCa. Elastin is an essential component of the ECM and constantly changes during tumor development. This article visualizes and quantifies elastin in magnetic resonance imaging (MRI) using a small molecule probe. Results were correlated with histological examinations. Using an elastin-specific molecular probe, we were able to make predictions about the cellular structure in relation to elastin and thus draw conclusions about the size of the tumor, with smaller tumors having a higher elastin content than larger tumors.
Human prostate cancer (PCa) is a type of malignancy and one of the most frequently diagnosed cancers in men. Elastin is an important component of the extracellular matrix and is involved in the structure and organization of prostate tissue. The present study examined prostate cancer in a xenograft mouse model using an elastin-specific molecular probe for magnetic resonance molecular imaging. Two different tumor sizes (500 mm3 and 1000 mm3) were compared and analyzed by MRI in vivo and histologically and analytically ex vivo. The T1-weighted sequence was used in a clinical 3-T scanner to calculate the relative contrast enhancement before and after probe administration. Our results show that the use of an elastin-specific probe enables better discrimination between tumors and surrounding healthy tissue. Furthermore, specific binding of the probe to elastin fibers was confirmed by histological examination and laser ablation–inductively coupled plasma–mass spectrometry (LA-ICP-MS). Smaller tumors showed significantly higher signal intensity (p > 0.001), which correlates with the higher proportion of elastin fibers in the histological evaluation than in larger tumors. A strong correlation was seen between relative enhancement (RE) and Elastica–van Gieson staining (R2 = 0.88). RE was related to inductively coupled plasma–mass spectrometry data for Gd and showed a correlation (R2 = 0.78). Thus, molecular MRI could become a novel quantitative tool for the early evaluation and detection of PCa.
KW - Magnetic resonance imaging
KW - MRI
KW - Molecular imaging
KW - Cancer
KW - LA-ICP-MS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538410
DO - https://doi.org/10.3390/biology10111217
VL - 10
IS - 11
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-53841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kader, A.
A1 - Kaufmann, Jan Ole
A1 - Mangarova, D. B.
A1 - Moeckel, J.
A1 - Brangsch, J.
A1 - Adams, L. C.
A1 - Zhao, J.
A1 - Reimann, C.
A1 - Saatz, Jessica
A1 - Traub, Heike
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Iron Oxide Nanoparticles for Visualization of Prostate Cancer in MRI
N2 - Prostate cancer (PCa) is one of the most common cancers in men. For detection and diagnosis of PCa, non-invasive methods, including magnetic resonance imaging (MRI), can reduce the risk potential of surgical intervention. To explore the molecular characteristics of the tumor, we investigated the applicability of ferumoxytol in PCa in a xenograft mouse model in two different tumor volumes, 500 mm3 and 1000 mm3. Macrophages play a key role in tumor progression, and they are able to internalize iron-oxide particles, such as ferumoxytol. When evaluating T2*-weighted sequences on MRI, a significant decrease of signal intensity between pre- and post-contrast images for each tumor volume (n = 14; p < 0.001) was measured. We, furthermore, observed a higher signal loss for a tumor volume of 500 mm3 than for 1000 mm3. These findings were confirmed by histological examinations and laser ablation inductively coupled plasma-mass spectrometry. The 500 mm3 tumors had 1.5% iron content (n = 14; sigma = 1.1), while the 1000 mm3 tumors contained only 0.4% iron (n = 14; sigma = 0.2). In vivo MRI data demonstrated a correlation with the ex vivo data (R2 = 0.75). The results of elemental analysis by inductively coupled plasma-mass spectrometry correlated strongly with the MRI data (R2 = 0.83) (n = 4). Due to its long retention time in the blood, biodegradability, and low toxicity to patients, ferumoxytol has great potential as a contrast agent for visualization PCa.
KW - Imaging
KW - Nanoparticle
KW - Cancer
KW - Iron oxide
KW - ICP-MS
KW - Magnetic resonance imaging
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550075
DO - https://doi.org/10.3390/cancers14122909
VL - 14
IS - 12
SP - 1
EP - 13
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55007
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kader, A.
A1 - Kaufmann, Jan Ole
A1 - Mangarova, D. B.
A1 - Moeckel, J.
A1 - Adams, L. C.
A1 - Brangsch, J.
A1 - Heyl, J. L.
A1 - Zhao, J.
A1 - Verlemann, C.
A1 - Karst, U.
A1 - Collettini, F.
A1 - Auer, T. A.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Collagen-specific molecular magnetic resonance imaging of prostate cancer
N2 - Constant interactions between tumor cells and the extracellular matrix (ECM) influence the progression of prostate cancer (PCa). One of the key components of the ECM are collagen fibers, since they are responsible for the tissue stiffness, growth, adhesion, proliferation, migration, invasion/metastasis, cell signaling, and immune recruitment of tumor cells. To explore this molecular marker in the content of PCa, we investigated two different tumor volumes (500 mm3 and 1000 mm3) of a xenograft mouse model of PCa with molecular magnetic resonance imaging (MRI) using a collagen-specific probe. For in vivo MRI evaluation, T1-weighted sequences before and after probe administration were analyzed. No significant signal difference between the two tumor volumes could be found. However, we detected a significant difference between the signal intensity of the peripheral tumor area and the central area of the tumor, at both 500 mm3 (p < 0.01, n = 16) and at 1000 mm3 (p < 0.01, n = 16). The results of our histologic analyses confirmed the in vivo studies: There was no significant difference in the amount of collagen between the two tumor volumes (p > 0.05), but within the tumor, higher collagen expression was observed in the peripheral area compared with the central area of the tumor. Laser ablation with inductively coupled plasma mass spectrometry further confirmed these results. The 1000 mm3 tumors contained 2.8 +- 1.0% collagen and the 500 mm3 tumors contained 3.2 +- 1.2% (n = 16). There was a strong correlation between the in vivo MRI data and the ex vivo histological data (y = 0.068x + 1.1; R2 = 0.74) (n = 16). The results of elemental analysis by inductively coupled plasma mass spectrometry supported the MRI data (y = 3.82x + 0.56; R2 = 0.79; n = 7). MRI with the collagen-specific probe in PCa enables differentiation between different tumor areas. This may help to differentiate tumor from healthy tissue, potentially identifying tumor areas with a specific tumor biology.
KW - Molecular imaging
KW - Magnetic resonance imaging
KW - MRI
KW - Prostate cancer
KW - Collagen
KW - Laser ablation-inductively coupled plasma-mass spectroscopy
KW - EP-3533
KW - Peptide probe
KW - Gd-DOTA
KW - Contrast agent
KW - Tumor
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568449
DO - https://doi.org/10.3390/ijms24010711
SN - 1422-0067
SN - 1661-6596
VL - 24
IS - 1
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-56844
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völzke, Jule L.
A1 - Hodjat Shamami, Parya
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Zimathies, Annett
A1 - Meyer, Klas
A1 - Weller, Michael G.
T1 - High-purity corundum as support for affinity extractions from complex samples
N2 - Nonporous corundum powder, known as an abrasive material in the industry, was functionalized covalently with protein binders to isolate and enrich specific proteins from complex matrices. The materials based on corundum were characterized by TEM, ESEM, BET, DLS, EDS, and zeta potential measurements. The strong Al-O-P bonds between the corundum surface and amino phosphonic acids were used to introduce functional groups for further conjugations. The common crosslinker glutaraldehyde was compared with a hyperbranched polyglycerol (PG) of around 10 kDa. The latter was oxidized with periodate to generate aldehyde groups that can covalently react with the amines of the surface and the amino groups from the protein via a reductive amination process. The amount of bound protein was quantified via aromatic amino acid analysis (AAAA). This work shows that oxidized polyglycerol can be used as an alternative to glutaraldehyde. With polyglycerol, more of the model protein bovine serum albumin (BSA) could be attached to the surface under the same conditions, and lower non-specific binding (NSB) was observed. As a proof of concept, IgG was extracted with protein A from crude human plasma. The purity of the product was examined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). A binding capacity of 1.8 mg IgG per gram of corundum powder was achieved. The advantages of corundum include the very low price, extremely high physical and chemical stability, pressure resistance, favorable binding kinetics, convenient handling, and flexible application.
KW - Corundum
KW - Sapphire
KW - Affinity chromatography
KW - Antibodies
KW - Self-assembled monolayers (SAM)
KW - Polyglycerol
KW - Dendrimer
KW - Nonspecific binding (NSB)
KW - Purification
KW - Solid-phase extraction (SPE)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559342
DO - https://doi.org/10.3390/separations9090252
VL - 9
IS - 9
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kazlagić, Anera
A1 - Russo, Francesco
A1 - Vogl, Jochen
A1 - Sturm, Patrick
A1 - Stephan, D.
A1 - Gluth, Gregor
ED - Resch-Genger, Ute
ED - Koch, Matthias
ED - Meermann, Björn
ED - Weller, Michael G.
T1 - Development of a sample preparation procedure for Sr isotope analysis of Portland cements
N2 - The 87Sr/86Sr isotope ratio can, in principle, be used for provenancing of cement. However, while commercial cements consist of multiple components, no detailed investigation into their individual 87Sr/86Sr isotope ratios or their influence on the integral 87Sr/86Sr isotope ratio of the resulting cement was conducted previously. Therefore, the present study aimed at determining and comparing the conventional 87Sr/86Sr isotope ratios of a diverse set of Portland cements and their corresponding Portland clinkers, the major component of these cements. Two approaches to remove the additives from the cements, i.e. to measure the conventional 87Sr/86Sr isotopic fingerprint of the clinker only, were tested, namely, treatment with a potassium hydroxide/sucrose solution and sieving on a 11-µm sieve. Dissolution in concentrated hydrochloric acid/nitric acid and in diluted nitric acid was employed to determine the 87Sr/86Sr isotope ratios of the cements and the individual clinkers. The aim was to find the most appropriate sample preparation procedure for cement provenancing, and the selection was realised by comparing the 87Sr/86Sr isotope ratios of differently treated cements with those of the corresponding clinkers. None of the methods to separate the clinkers from the cements proved to be satisfactory. However, it was found that the 87Sr/86Sr isotope ratios of clinker and cement generally corresponded, meaning that the latter can be used as a proxy for the clinker 87Sr/86Sr isotope ratio. Finally, the concentrated hydrochloric acid/nitric acid dissolution method was found to be the most suitable sample preparation method for the cements; it is thus recommended for 87Sr/86Sr isotope analyses for cement provenancing.
KW - Cement
KW - Provenancing
KW - Sr isotopes
KW - Portland clinker
KW - Dissolution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542239
DO - https://doi.org/10.1007/s00216-021-03821-7
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - 15 (Topical collection: Analytical methods and applications in the materials and life sciences)
SP - 4379
EP - 4389
PB - Springer
CY - Berlin
AN - OPUS4-54223
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Meermann, Björn
A1 - Koch, Matthias
A1 - Weller, Michael G.
T1 - Editorial: Analytical methods and applications in materials and life sciences
N2 - Current trends in materials and life sciences are flanked by the need to push detection limits to single molecules or single cells, enable the characterization of increasingly complex matrices or sophisticated nanostructures, speed up the time of analysis, reduce instrument complexity and costs, and improve the reliability of data. This requires suitable analytical tools such as spectroscopic, separation and imaging techniques, mass spectrometry, and hyphenated techniques as well as sensors and their adaptation to application-specific challenges in the environmental, food, consumer product, health sector, nanotechnology, and bioanalysis. Increasing concerns about health threatening known or emerging pollutants in drinking water, consumer products, and food and about the safety of nanomaterials led to a new awareness of the importance of analytical sciences. Another important driver in this direction is the increasing demand by legislation, particularly in view of the 17 sustainable development goals by the United Nations addressing clean energy, industry, and innovation, sustainable cities, clean water, and responsible consumption and production. In this respect, also the development of analytical methods that enable the characterization of material flows in production processes and support recycling concepts of precious raw materials becomes more and more relevant. In the future, this will provide the basis for greener production in the chemical industry utilizing recycled or sustainable starting materials.
This makes analytical chemistry an essential player in terms of the circular economy helping to increase the sustainability of production processes. In the life sciences sector, products based on proteins, such as therapeutic and diagnostic antibodies, increase in importance. These increasingly biotechnologically produced functional biomolecules pose a high level of complexity of matrix and structural features that can be met only by highly advanced methods for separation, characterization, and detection. In addition, metrological traceability and target definition are still significant challenges for the future, particularly in the life sciences.
However, innovative reference materials as required for the health and food sector and the characterization of advanced materials can only be developed when suitable analytical protocols are available. The so-called reproducibility crisis in sciences underlines the importance of improved measures of quality control for all kinds of measurements and material characterization. This calls for thorough method validation concepts, suitable reference materials, and regular interlaboratory comparisons of measurements as well as better training of scientists in analytical sciences.
The important contribution of analytical sciences to these developments is highlighted by a broad collection of research papers, trend articles, and critical reviews from these different application fields. Special emphasis is dedicated to often-overlooked quality assurance and reference materials.
T2 - 150 years BAM: Science with impact
CY - Berlin, Germany
DA - 01.01.2021
KW - Analysis
KW - Life sciences
KW - Analytical sciences
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Nanoparticle
KW - Sensor
KW - Material sciences
KW - Pollutant
KW - Environment
KW - Method
KW - Limit of detection
KW - 150th anniversary
KW - ABC
KW - BAM
KW - Collection
KW - Editorial
KW - Special issue
KW - Bundesanstalt für Materialforschung und -prüfung
KW - Jahrestag
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550720
DO - https://doi.org/10.1007/s00216-022-04082-8
SN - 1618-2642
SN - 1618-2650
VL - 414
IS - Topical collection: Analytical methods and applications in the materials and life sciences
SP - 4267
EP - 4268
PB - Springer
CY - Berlin
AN - OPUS4-55072
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reinmuth-Selzle, K.
A1 - Kampf, C. J.
A1 - Lucas, K.
A1 - Lang-Yona, N.
A1 - Fröhlich-Nowoisky, J.
A1 - Shiraiwa, M.
A1 - Lakey, P. S. J.
A1 - Lai, S.
A1 - Liu, F.
A1 - Kunert, A. T.
A1 - Ziegler, K.
A1 - Shen, F.
A1 - Sgarbanti, R.
A1 - Weber, B.
A1 - Bellinghausen, I.
A1 - Saloga, J.
A1 - Weller, Michael G.
A1 - Duschl, A.
A1 - Schuppan, D.
A1 - Pöschl, U.
T1 - Air pollution and climate change effects on allergies in the anthropocene: Abundance, interaction, and modification of allergens and adjuvants
N2 - Air pollution and climate change are potential drivers for the increasing burden of allergic diseases. The molecular mechanisms by which air pollutants and climate parameters may influence allergic diseases, however, are complex and elusive. This article provides an overview of physical, chemical and biological interactions between air pollution, climate change, allergens, adjuvants and the immune system, addressing how these interactions may promote the development of allergies. We reviewed and synthesized key findings from atmospheric, climate, and biomedical research. The current state of knowledge, open questions, and future research perspectives are outlined and discussed. The Anthropocene, as the present era of globally pervasive anthropogenic influence on planet Earth and, thus, on the human environment, is characterized by a strong increase of carbon dioxide, ozone, nitrogen oxides, and combustion- or traffic-related particulate matter in the atmosphere. These environmental factors can enhance the abundance and induce chemical modifications of allergens, increase oxidative stress in the human body, and skew the immune system toward allergic reactions. In particular, air pollutants can act as adjuvants and alter the immunogenicity of allergenic proteins, while climate change affects the atmospheric abundance and human exposure to bioaerosols and aeroallergens. To fully understand and effectively mitigate the adverse effects of air pollution and climate change on allergic diseases, several challenges remain to be resolved. Among these are the identification and quantification of immunochemical reaction pathways involving allergens and adjuvants under relevant environmental and physiological conditions.
KW - Allergie
KW - Klimaveränderung
KW - Luftverschmutzung
KW - Partikel
KW - Ozon
KW - Stickoxide
KW - Allergene
KW - Adjuvantien
KW - PALM
KW - DAMP
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404531
DO - https://doi.org/10.1021/acs.est.6b04908
SN - 1520-5851
SN - 0013-936X
VL - 51
IS - 8
SP - 4119
EP - 4141
PB - American Chemical Society (ACS)
CY - Washington
AN - OPUS4-40453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbas, Ioana M.
A1 - Vranic, M.
A1 - Hoffmann, Holger
A1 - El-Khatib, Ahmed H.
A1 - Montes-Bayón, M.
A1 - Möller, H. M.
A1 - Weller, Michael G.
T1 - Investigations of the copper peptide hepcidin-25 by LC-MS/MS and NMR (+)
N2 - Hepcidin-25 was identified as the main iron regulator in the human body, and it by binds to the sole iron-exporter ferroportin. Studies showed that the N-terminus of hepcidin is responsible for this interaction, the same N-terminus that encompasses a small copper(II)-binding site known as the ATCUN (amino-terminal Cu(II)- and Ni(II)-binding) motif. Interestingly, this copper-binding property is largely ignored in most papers dealing with hepcidin-25. In this context, detailed investigations of the complex formed between hepcidin-25 and copper could reveal insight into its biological role. The present work focuses on metal-bound hepcidin-25 that can be considered the biologically active form. The first part is devoted to the reversed-phase chromatographic separation of copper-bound and copper-free hepcidin-25 achieved by applying basic mobile phases containing 0.1% ammonia. Further, mass spectrometry (tandem mass spectrometry (MS/MS), high-resolution mass spectrometry HRMS)) and nuclear magnetic resonance (NMR) spectroscopy were employed to characterize the copper-peptide. Lastly, a three-dimensional (3D)model of hepcidin-25with bound copper(II) is presented. The identification of metal complexes and potential isoforms and isomers, from which the latter usually are left undetected by mass spectrometry, led to the conclusion that complementary analytical methods are needed to characterize a peptide calibrant or reference material comprehensively. Quantitative nuclear magnetic resonance (qNMR), inductively-coupled plasma mass spectrometry (ICP-MS), ion-mobility spectrometry (IMS) and chiral amino acid analysis (AAA) should be considered among others.
KW - Metalloprotein
KW - Peptide
KW - Chromatography
KW - High pH
KW - Mobile phase
KW - Metrology
KW - Purity
KW - Reference material
KW - ATCUN
KW - Copper
KW - Nickel
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457796
UR - http://www.mdpi.com/1422-0067/19/8/2271
DO - https://doi.org/10.3390/ijms19082271
SN - 1422-0067
VL - 19
IS - 8
SP - 2271, 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-45779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwaar, Timm
A1 - Lettow, Maike
A1 - Remmler, Dario
A1 - Börner, H. G.
A1 - Weller, Michael G.
T1 - Efficient Screening of Combinatorial Peptide Libraries by Spatially Ordered Beads Immobilized on Conventional Glass Slides
N2 - Screening of one-bead-one-compound (OBOC) libraries is a proven procedure for the identification of protein-binding ligands. The demand for binders with high affinity and specificity towards various targets has surged in the biomedical and pharmaceutical field in recent years. The traditional peptide screening involves tedious steps such as affinity selection, bead picking, sequencing, and characterization. Herein, we present a high-throughput “all-on-one chip” system to avoid slow and technically complex bead picking steps. On a traditional glass slide provided with an electrically conductive tape, beads of a combinatorial peptide library are aligned and immobilized by application of a precision sieve. Subsequently, the chip is incubated with a fluorophore-labeled target protein. In a fluorescence scan followed by matrix-assisted laser desorption/ionization (MALDI)-time of flight (TOF) mass spectrometry, high-affinity binders are directly and unambiguously sequenced with high accuracy without picking of the positive beads. The use of an optimized ladder sequencing approach improved the accuracy of the de-novo sequencing step to nearly 100%. The new technique was validated by employing a FLAG-based model system, identifying new peptide binders for the monoclonal M2 anti-FLAG antibody, and was finally utilized to search for IgG-binding peptides. In the present format, more than 30,000 beads can be screened on one slide.
KW - Peptide library
KW - HTS
KW - Target
KW - MALDI
KW - Mass spectrometry
KW - Biochip
KW - Lab-on-a-Chip
KW - Array
KW - Screening
KW - Ladder sequencing
KW - Binder
KW - Pharmaceutical
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-478973
UR - https://www.mdpi.com/2571-5135/8/2/11
DO - https://doi.org/10.3390/ht8020011
VL - 8
IS - 2
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-47897
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schroeder, Barbara
A1 - Le Xuan, Hoa
A1 - Völzke, Jule L.
A1 - Weller, Michael G.
T1 - Preactivation Crosslinking - An Efficient Method for the Oriented Immobilization of Antibodies
N2 - Crosslinking of proteins for their irreversible immobilization on surfaces is a proven and popular method. However, many protocols lead to random orientation and the formation of undefined or even inactive by-products. Most concepts to obtain a more targeted conjugation or immobilization requires the recombinant modification of at least one binding partner, which is often impractical or prohibitively expensive. Here a novel method is presented, which is based on the chemical preactivation of Protein A or G with selected conventional crosslinkers. In a second step, the antibody is added, which is subsequently crosslinked in the Fc part. This leads to an oriented and covalent immobilization of the immunoglobulin with a very high yield. Protocols for Protein A and Protein G with murine and human IgG are presented. This method may be useful for the preparation of columns for affinity chromatography, immunoprecipitation, antibodies conjugated to magnetic particles, permanent and oriented immobilization of antibodies in biosensor systems, microarrays, microtitration plates or any other system, where the loss of antibodies needs to be avoided, and maximum binding capacity is desired. This method is directly applicable even to antibodies in crude cell culture supernatants, raw sera or protein-stabilized antibody preparations without any purification nor enrichment of the IgG. This new method delivered much higher signals as a traditional method and, hence, seems to be preferable in many applications.
KW - Antibody coating
KW - Proximity-enhanced reaction
KW - Immunoglobulins
KW - IgG
KW - Protein A
KW - Protein G
KW - Immunoprecipitation
KW - Immunocapture
KW - Regeneration
KW - Biosensor
KW - Immunosensor
KW - Affinity chromatography
KW - Immunoaffinity extraction
KW - Oriented immobilization
KW - Immunoassay
KW - Bioconjugation
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479786
DO - https://doi.org/10.3390/mps2020035
SN - 2409-9279
VL - 2
IS - 2
SP - 1
EP - 14
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-47978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reimann, C.
A1 - Kaufmann, Jan Ole
A1 - Adams, L. C.
A1 - Onthank, D. C.
A1 - Thöne-Reineke, C.
A1 - Robinson, S. P.
A1 - Hamm, B.
A1 - Botnar, R. M.
A1 - Makowski, M. R.
T1 - Dual-probe molecular MRI for the in vivo characterization of atherosclerosis in a mouse model: Simultaneous assessment of plaque inflammation and extracellular-matrix remodeling
N2 - Molecular MRI is a promising in-vivo modality to detect and quantify morphological and molecular vessel-wall changes in atherosclerosis. The combination of different molecular biomarkers may improve the risk stratification of patients. This study aimed to investigate the feasibility of simultaneous visualization and quantification of plaque-burden and inflammatory activity by dual-probe molecular MRI in a mouse-model of progressive atherosclerosis and in response-to-therapy. Homozygous apolipoprotein E knockout mice (ApoE−/−) were fed a high-fat-diet (HFD) for up to four-months prior to MRI of the brachiocephalic-artery. To assess response-to-therapy, a statin was administered for the same duration. MR imaging was performed before and after administration of an elastin-specific gadolinium-based and a macrophage-specific iron-oxide-based probe. Following in-vivo MRI, samples were analyzed using histology, immunohistochemistry, inductively-coupled-mass-spectrometry and laser-inductively-coupled-mass-spectrometry. In atherosclerotic-plaques, intraplaque expression of elastic-fibers and inflammatory activity were not directly linked. While the elastin-specific probe demonstrated the highest accumulation in advanced atherosclerotic-plaques after four-months of HFD, the iron-oxide-based probe showed highest accumulation in early atherosclerotic-plaques after two-months of HFD. In-vivo measurements for the elastin and iron-oxide-probe were in good agreement with ex-vivo histopathology (Elastica-van-Giesson stain: y = 298.2 + 5.8, R2 = 0.83, p < 0.05; Perls‘ Prussian-blue-stain: y = 834.1 + 0.67, R2 = 0.88, p < 0.05). Contrast-to-noise-ratio (CNR) measurements of the elastin probe were in good agreement with ICP-MS (y = 0.11x-11.3, R² = 0.73, p < 0.05). Late stage atherosclerotic-plaques displayed the strongest increase in both CNR and gadolinium concentration (p < 0.05). The gadolinium probe did not affect the visualization of the iron-oxide-probe and vice versa. This study demonstrates the feasibility of simultaneous assessment of plaque-burden and inflammatory activity by dual-probe molecular MRI of progressive atherosclerosis. The in-vivo detection and quantification of different MR biomarkers in a single scan could be useful to improve characterization of atherosclerotic-lesions.
KW - In-vivo
KW - Molecular MRI
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-492514
DO - https://doi.org/10.1038/s41598-019-50100-8
VL - 9
IS - 1
SP - Article number: 13827
PB - Nature
AN - OPUS4-49251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reimann, C.
A1 - Brangsch, J.
A1 - Kaufmann, Jan Ole
A1 - Adams, L. C.
A1 - Onthank, D. C.
A1 - Thöne-Reineke, C.
A1 - Robinson, S. P.
A1 - Hamm, B.
A1 - Botnar, R. M.
A1 - Makowski, M. R.
T1 - Dual-probe molecular MRI for the in vivo characterization of atherosclerosis in a mouse model: Simultaneous assessment of plaque inflammation and extracellular matrix remodeling
N2 - Molecular MRI is a promising in-vivo modality to detect and quantify morphological and molecular vessel-wall changes in atherosclerosis. The combination of different molecular biomarkers may improve the risk stratification of patients. This study aimed to investigate the feasibility of simultaneous visualization and quantification of plaque-burden and inflammatory activity by dual-probe molecular
MRI in a mouse-model of progressive atherosclerosis and in response-to-therapy. Homozygous apolipoprotein E knockout mice (ApoE−/−) were fed a high-fat-diet (HFD) for up to four-months prior to MRI of the brachiocephalic-artery. To assess response-to-therapy, a statin was administered for the same duration. MR imaging was performed before and after administration of an elastin-specific gadolinium-based and a macrophage-specific iron-oxide-based probe. Following in-vivo MRI, samples were analyzed using histology, immunohistochemistry, inductively-coupled-mass-spectrometry and laser-inductively-coupled-mass-spectrometry. In atherosclerotic-plaques, intraplaque expression
of elastic-fibers and inflammatory activity were not directly linked. While the elastin-specific probe demonstrated the highest accumulation in advanced atherosclerotic-plaques after four-months of HFD, the iron-oxide-based probe showed highest accumulation in early atherosclerotic-plaques after two months of HFD. In-vivo measurements for the elastin and iron-oxide-probe were in good agreement
with ex-vivo histopathology (Elastica-van-Giesson stain: y = 298.2 + 5.8, R2 = 0.83, p < 0.05; Perls‘ Prussian-blue-stain: y = 834.1 + 0.67, R2 = 0.88, p < 0.05). Contrast-to-noise-ratio (CNR) measurements of the elastin probe were in good agreement with ICP-MS (y = 0.11x-11.3, R² = 0.73, p < 0.05). Late stage atherosclerotic-plaques displayed the strongest increase in both CNR and gadolinium concentration (p < 0.05). The gadolinium probe did not affect the visualization of the iron-oxide-probe and vice versa. This study demonstrates the feasibility of simultaneous assessment of plaque-burden.
KW - Gadolinium
KW - Elastin
KW - Probe
KW - Iron oxide
KW - Ferumoxytol
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497066
DO - https://doi.org/10.1038/s41598-019-50100-8
VL - 9
SP - 13827
PB - Springer Nature
AN - OPUS4-49706
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernevic, Bogdan
A1 - El-Khatib, Ahmed H.
A1 - Jakubowski, Norbert
A1 - Weller, Michael G.
T1 - Online immunocapture ICP‑MS for the determination of the metalloprotein ceruloplasmin in human serum
N2 - The human copper-protein ceruloplasmin (Cp) is the major copper-containing protein in the human body. The accurate determination of Cp is mandatory for the reliable diagnosis of several diseases. However, the analysis of Cp has proven to be difficult. The aim of our work was a proof of concept for the determination of a metalloprotein-based on online immunocapture ICP-MS. The immuno-affinity step is responsible for the enrichment and isolation of the analyte from serum, whereas the compound-independent quantitation with ICP-MS delivers the sensitivity,
precision, and large dynamic range. Off-line ELISA (enzyme-linked immunosorbent assay) was used in parallel to confirm the elution profile of the analyte with a structure-selective method. The total protein elution was observed with the 32S mass trace. The ICP-MS signals were normalized on a 59Co signal. The human copper-protein Cp could be selectively determined. This was shown with pure Cp and with a sample of human serum. The good correlation with off-line ELISA shows that Cp could be captured and eluted selectively from the anti-Cp affinity column and subsequently determined by the copper signal of ICP-MS.
KW - ELISA
KW - Affinity chromatography
KW - Affinity extraction
KW - IgY
KW - Chicken antibodies
KW - Immunoaffinity extraction
KW - Copper
KW - Diagnostics
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446157
UR - https://bmcresnotes.biomedcentral.com/articles/10.1186/s13104-018-3324-7
UR - https://static-content.springer.com/esm/art%3A10.1186%2Fs13104-018-3324-7/MediaObjects/13104_2018_3324_MOESM1_ESM.pdf
UR - https://static-content.springer.com/esm/art%3A10.1186%2Fs13104-018-3324-7/MediaObjects/13104_2018_3324_MOESM2_ESM.pdf
DO - https://doi.org/10.1186/s13104-018-3324-7
SN - 1756-0500
VL - 11
IS - 1
SP - Article 213, 1
EP - 5
PB - Springer Nature
CY - Heidelberg
AN - OPUS4-44615
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ponader, Marco
A1 - Weller, Michael G.
T1 - Affinitätschromatografie - Neues Trägermaterial aus Borosilikatglas
N2 - Therapeutische Antikörper sind innerhalb weniger Jahre zur wichtigsten pharmazeutischen Produktklasse aufgestiegen. Für 2023 werden weltweite Umsätze von über 200 Milliarden USD erwartet. Auch diagnostische Antikörper sind mittlerweile unverzichtbare Produkte, auf deren Basis zahllose Immunoassays und andere Schnelltests entwickelt wurden. Neben der bereits sehr aufwendigen Herstellung von Antikörpern ist deren Aufreinigung aus komplexen Zellkulturmedien oder Blutseren und -plasmen zu einem Engpass in der Produktion und Nutzung dieser komplexen Proteine geworden. Schnelle und einfache Reinigungsmethoden für Antikörper sind daher sehr gefragt.
KW - Affinitätschromatographie
KW - Affinitätsextraktion
KW - Antikörper
KW - Glasmonolith
KW - Additive Fertigung
KW - IgG
KW - Immunglobulin
KW - HPLC
KW - FPLC
KW - biokompatibel
KW - Borosilikatglas
KW - gesintert
KW - Titan-Halterung
KW - Druckstabilität
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477490
UR - https://www.chemiextra.com/
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
IS - 4
SP - 16
EP - 17
PB - Sigwerb
CY - Zug
AN - OPUS4-47749
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bosc-Bierne, Gaby
A1 - Ewald, Shireen
A1 - Kreuzer, Oliver J.
A1 - Weller, Michael G.
T1 - Efficient Quality Control of Peptide Pools by UHPLC and Simultaneous UV and HRMS Detection
N2 - Peptide pools consist of short amino acid sequences and have proven to be versatile tools in various research areas in immunology and clinical applications. They are commercially available in many different compositions and variants. However, unlike other reagents that consist of only one or a few compounds, peptide pools are highly complex products which makes their quality control a major challenge. Quantitative peptide analysis usually requires sophisticated methods, in most cases isotope-labeled standards and reference materials. Usually, this would be prohibitively laborious and expensive. Therefore, an approach is needed to provide a practical and feasible method for quality control of peptide pools. With insufficient quality control, the use of such products could lead to incorrect experimental results, worsening the well-known reproducibility crisis in the biomedical sciences. Here we propose the use of ultra-high performance liquid chromatography (UHPLC) with two detectors, a standard UV detector at 214 nm for quantitative analysis and a high-resolution mass spectrometer (HRMS) for identity confirmation. To be cost-efficient and fast, quantification and identification are performed in one chromatographic run. An optimized protocol is shown, and different peak integration methods are compared and discussed. This work was performed using a peptide pool known as CEF advanced, which consists of 32 peptides derived from cytomegalovirus (CMV), Epstein–Barr virus (EBV) and influenza virus, ranging from 8 to 12 amino acids in length.
N2 - Peptidpools bestehen aus kurzen Aminosäuresequenzen und haben sich als vielseitige Werkzeuge in verschiedenen Forschungsbereichen der Immunologie und bei klinischen Anwendungen erwiesen. Sie sind in vielen verschiedenen Zusammensetzungen und Varianten im Handel erhältlich. Im Gegensatz zu anderen Reagenzien, die nur aus einer oder wenigen Verbindungen bestehen, sind Peptidpools jedoch hochkomplexe Produkte, was ihre Qualitätskontrolle zu einer großen Herausforderung macht. Die quantitative Peptidanalyse erfordert in der Regel ausgefeilte Methoden, in den meisten Fällen isotopenmarkierte Standards und Referenzmaterialien. Dies ist in der Regel sehr aufwändig und teuer. Daher wird ein Ansatz benötigt, der eine praktische und praktikable Methode zur Qualitätskontrolle von Peptidpools bietet. Bei unzureichender Qualitätskontrolle könnte die Verwendung solcher Produkte zu falschen Versuchsergebnissen führen, was das bekannte Problem der Reproduzierbarkeit in den biomedizinischen Wissenschaften noch verschärfen würde. Hier schlagen wir die Verwendung der Ultrahochleistungs-Flüssigkeitschromatographie (UHPLC) mit zwei Detektoren vor, einem Standard-UV-Detektor bei 214 nm für die quantitative Analyse und einem hochauflösenden Massenspektrometer (HRMS) für die Identitätsbestätigung. Um kosteneffizient und schnell zu sein, werden Quantifizierung und Identifizierung in einem einzigen chromatographischen Lauf durchgeführt. Es wird ein optimiertes Protokoll gezeigt, und es werden verschiedene Peak-Integrationsmethoden verglichen und diskutiert. Für diese Arbeit wurde ein Peptidpool verwendet, der als CEF advanced bekannt ist und aus 32 Peptiden besteht, die vom Cytomegalovirus (CMV), Epstein-Barr-Virus (EBV) und Influenzavirus stammen und zwischen 8 und 12 Aminosäuren lang sind.
KW - Synthetic peptides
KW - Quality control
KW - Impurites
KW - Byproducts
KW - Degradation
KW - Mass spectrometry
KW - Orbitrap
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602299
DO - https://doi.org/10.3390/separations11050156
SN - 2297-8739
VL - 11
IS - 5
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-60229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tannenberg, Robert
A1 - Paul, Martin
A1 - Röder, Bettina
A1 - Gande, S. L.
A1 - Sreeramulu, S.
A1 - Saxena, K.
A1 - Richter, C.
A1 - Schwalbe, H.
A1 - Swart, C.
A1 - Weller, Michael G.
T1 - Chemiluminescence biosensor for the determination of cardiac troponin I (cTnI)
N2 - Cardiac troponin I (cTnI) is a crucial biomarker for diagnosing cardiac vascular diseases, including acute myocardial infarction (AMI). This study presents a proof-of-concept chemiluminescence-based immunosensor for rapid and accurate measurement of cTnI, with the potential for online monitoring. The immunosensor incorporates a flow cell design and a sensitive complementary metal-oxide-semiconductor (CMOS) camera for optical readout. A microfluidic setup was established to enable selective and quasi-online determination of cTnI within ten minutes. The sensor was tested with recombinant cTnI in phosphate buffer, demonstrating measurements in the concentration range of 2–25 µg/L, with a limit of detection (LoD) of 0.6 µg/L (23 pmol/L) achieved using the optimized system. The immunosensor exhibited high selectivity, as no cross-reactivity was observed with other recombinant proteins such as cTnT and cTnC at a concentration of 16 µg/L. Measurements with diluted blood plasma and serum yielded an LoD of 60 µg/L (2.4 nmol/L) and 70 µg/L (2.9 nmol/L), respectively. This biosensor offers a promising approach for the rapid and sensitive detection of cTnI, contributing to the diagnosis and management of acute myocardial infarction and other cardiac vascular diseases.
N2 - Das kardiale Troponin I (cTnI) ist ein wichtiger Biomarker für die Diagnose von Herz-Kreislauf-Erkrankungen, einschließlich des akuten Myokardinfarkts (AMI). In dieser Studie wird ein auf Chemilumineszenz basierender Immunsensor für die schnelle und genaue Messung von cTnI vorgestellt, der das Potenzial für eine Online-Überwachung hat. Der Immunsensor besteht aus einer Durchflusszelle und einer empfindlichen CMOS-Kamera (Complementary Metal-Oxide-Semiconductor) zur optischen Detektion. Es wurde ein mikrofluidischer Aufbau entwickelt, der eine selektive und quasi Online-Bestimmung von cTnI innerhalb von zehn Minuten ermöglicht. Der Sensor wurde mit rekombinantem cTnI in Phosphatpuffer getestet und zeigte einen Messbereich von 2-25 µg/L, wobei mit dem optimierten System eine Nachweisgrenze (LoD) von 0,6 µg/L (23 pmol/L) erreicht wurde. Der Immunsensor zeigte eine hohe Selektivität, da keine Kreuzreaktivität mit anderen rekombinanten Proteinen wie cTnT und cTnC bei einer Konzentration von 16 µg/L beobachtet wurde. Messungen mit verdünntem Blutplasma und Serum ergaben einen LoD von 60 µg/L (2,4 nmol/L) bzw. 70 µg/L (2,9 nmol/L). Dieser Biosensor bietet einen vielversprechenden Ansatz für den schnellen und empfindlichen Nachweis von cTnI, der zur Diagnose und Behandlung des akuten Myokardinfarkts und anderer kardialer Gefäßerkrankungen beitragen kann.
KW - Acute myocardial infarction
KW - Heart attack
KW - Emergency
KW - Diagnosis
KW - Cardiac troponin
KW - Biomarker
KW - Immunosensor
KW - Biosensor
KW - Chemiluminescence
KW - Luminol
KW - Peroxidase
KW - Monoclonal antibodies
KW - Flow injection immunoassay
KW - Immunometric assay
KW - Immunometric biosensor
KW - Microfluidic system
KW - Monolithic column
KW - Online biosensor
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575471
DO - https://doi.org/10.3390/bios13040455
SN - 2079-6374
VL - 13
IS - 4
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-57547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kader, A.
A1 - Brangsch, J.
A1 - Kaufmann, Jan Ole
A1 - Zhao, J.
A1 - Mangarova, D. B.
A1 - Moeckel, J.
A1 - Adams, L. C.
A1 - Sack, I.
A1 - Taupitz, M.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Molecular MR Imaging of Prostate Cancer
N2 - This review summarizes recent developments regarding molecular imaging markers for magnetic resonance imaging (MRI) of prostate cancer (PCa). Currently, the clinical standard includes MR imaging using unspecific gadolinium-based contrast agents. Specific molecular probes for the diagnosis of PCa could improve the molecular characterization of the tumor in a non-invasive examination. Furthermore, molecular probes could enable targeted therapies to suppress tumor growth or reduce the tumor size.
KW - Prostate cancer
KW - Magnetic resonance imaging
KW - Molecular imaging
KW - Imaging
KW - Molecular marker
KW - Screening
KW - MRI
KW - Diagnosis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519503
DO - https://doi.org/10.3390/biomedicines9010001
VL - 9
IS - 1
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-51950
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völzke, Jule L.
A1 - Smatty, Sarah
A1 - Döring, Sarah
A1 - Ewald, Shireen
A1 - Oelze, Marcus
A1 - Fratzke, Franziska
A1 - Flemig, Sabine
A1 - Konthur, Zoltán
A1 - Weller, Michael G.
T1 - Efficient Purification of Polyhistidine-Tagged Recombinant Proteins Using Functionalized Corundum Particles
N2 - Immobilized metal affinity chromatography (IMAC) is a widely used technique for purifying polyhistidine-tagged recombinant proteins. However, it often has practical limitations that require complex optimizations and additional steps for purification. In this study, we introduce functionalized corundum particles as a novel, efficient, and economical method for purifying recombinant proteins in a column-free format. The corundum surface is modified with amino silane APTES, followed by EDTA dianhydride, and then loaded with nickel ions. We used the Kaiser test to monitor the modification process and ICP-MS to quantify the metal-binding capacity. To evaluate the system, we used His-tagged protein A/G (PAG) mixed with bovine serum albumin (BSA). The corundum particles exhibited a binding capacity of approximately 3 mg of protein per gram of corundum or 2.4 mg per 1 mL of corundum suspension. We also examined cytoplasm obtained from different E. coli strains as an example of a complex matrix. Varying the imidazole concentration in the loading and washing buffers showed that higher concentrations during loading improved purity. Even with sample volumes as large as one liter, we successfully isolated recombinant proteins down to a concentration of 1 µg/mL. We found higher purity levels with corundum when comparing the corundum material to standard Ni–NTA agarose beads. We successfully purified His6-MBP-mSA2, a fusion protein comprising monomeric streptavidin and maltose-binding protein, from E. coli cytoplasm, demonstrating the method's applicability. We also purified SARS-CoV-2-S-RBD-His8 expressed in human Expi293F cells, confirming its suitability for mammalian cell culture supernatants. The material cost of the nickel-loaded corundum material (without regeneration) is estimated to be less than 30 cents per gram of functionalized support or 10 cents per milligram of isolated protein. Another advantage of this system is the exceptional physical and chemical stability of corundum particles. Overall, we have demonstrated that this novel material offers an efficient, robust, and cost-effective purification platform for His-tagged proteins, even in challenging, complex matrices and large sample volumes with low product concentrations. This method has potential applications in both small laboratories and large-scale industrial settings.
N2 - Die immobilisierte Metallaffinitätschromatographie (IMAC) ist eine weit verbreitete Technik zur Reinigung von rekombinanten Proteinen mit Polyhistidin-Markierung. Sie hat jedoch oft praktische Einschränkungen, die komplexe Optimierungen und zusätzliche Schritte für die Aufreinigung erfordern. In dieser Studie stellen wir funktionalisierte Korundpartikel als neuartige, effiziente und wirtschaftliche Methode zur Reinigung rekombinanter Proteine in einem säulenfreien Format vor. Die Korundoberfläche wird mit dem Aminosilan APTES und anschließend mit EDTA-Dianhydrid modifiziert und dann mit Nickelionen beladen. Wir haben den Kaiser-Test zur Überwachung des Modifizierungsprozesses und ICP-MS zur Quantifizierung der Metallbindungskapazität verwendet. Zur Charakterisierung des Systems verwendeten wir His-markiertes Protein A/G (PAG) in Kombination mit Rinderserumalbumin (BSA). Die Korundpartikel wiesen eine Bindungskapazität von etwa 3 mg Protein pro Gramm Korund oder 2,4 mg pro 1 ml Korundsuspension auf. Als Beispiel für eine komplexe Matrix untersuchten wir auch Zytoplasma, das aus verschiedenen E. coli-Stämmen gewonnen wurde. Die Variation der Imidazolkonzentration in den Lade- und Waschpuffern zeigte, dass höhere Konzentrationen beim Laden die Reinheit verbesserten. Selbst bei einem Probenvolumen von bis zu einem Liter konnten wir rekombinante Proteine von 1 µg/mL isolieren. Beim Vergleich des Korundmaterials mit Standard-Ni-NTA-Agarose-Beads stellten wir einen höheren Reinheitsgrad mit Korund fest. Wir reinigten erfolgreich His6-MBP-mSA2 aus E. coli-Zytoplasma, ein Fusionsprotein, das aus monomerem Streptavidin und Maltose-bindendem Protein besteht. Wir reinigten auch SARS-CoV-2-S-RBD-His8, das in humanen Expi293F-Zellen exprimiert wurde, und bestätigten damit die Eignung des Materials für Zellkulturüberstände von Säugetieren. Die Materialkosten für nickelbeladenen Korund (ohne Regenerierung) werden auf weniger als 30 Cent pro Gramm funktionalisierten Trägers oder 10 Cent pro Milligramm isolierten Proteins geschätzt. Ein weiterer Vorteil dieses Systems ist die außergewöhnliche physikalische und chemische Stabilität der Korundpartikel. Insgesamt haben wir gezeigt, dass dieses neuartige Material eine effiziente, robuste und kostengünstige Reinigungsplattform für His-markierte Proteine bietet, selbst bei schwierigen, komplexen Matrices und großen Probenmengen mit niedrigen Produktkonzentrationen. Diese Methode könnte sowohl in kleinen Labors als auch in der Großindustrie eingesetzt werden.
KW - Aluminum oxide
KW - Sapphire
KW - Ethylenediaminetetraacetic acid
KW - Nickel chelate
KW - EDTAD
KW - HexaHis-Tag
KW - His6
KW - 6xHis
KW - His8
KW - Bioseparation
KW - IMAC purification
KW - Immunocapture
KW - Affinity chromatography
KW - Carrier
KW - Nickel
KW - Recombinant protein
KW - Escherichia coli
KW - Bacterial lysates
KW - Cytoplasm
KW - Polishing
KW - Downstream processing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575672
DO - https://doi.org/10.3390/biotech12020031
VL - 12
IS - 2
SP - 1
EP - 18
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-57567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Martin
A1 - Weller, Michael G.
T1 - Antibody screening by microarray technology - Direct identification of selective high-affinity clones
N2 - The primary screening of hybridoma cells is a time-critical and laborious step during the development of monoclonal antibodies. Often, critical errors occur in this phase, which supports the notion that the generation of monoclonal antibodies with hybridoma technology is difficult to control and hence, a risky venture. We think that it is crucial to improve the screening process to eliminate most of the critical deficits of the conventional approach. With this new microarray-based procedure, several advances could be achieved: Selectivity for excellent binders, high-throughput, reproducible signals, avoidance of misleading avidity (multivalency) effects, and performance of simultaneous competition experiments. The latter can also be used to select clones of desired cross-reactivity properties. In this paper, a model system with two excellent clones against carbamazepine, two weak clones, and blank supernatant containing fetal bovine serum was designed to examine the effectiveness of the new system. The excellent clones could be detected largely independent of the immunoglobulin G (IgG) concentration, which is usually unknown during the clone screening since the determination and subsequent adjustment of the antibody concentration are not feasible in most cases. Furthermore, in this approach, the enrichment, isolation, and purification of IgG for characterization is not necessary. Raw cell culture supernatant can be used directly, even when fetal calf serum (FCS) or other complex media is used. In addition, an improved method for the oriented antibody-immobilization on epoxy-silanized slides is presented. Based on the results of this model system with simulated hybridoma supernatants, we conclude that this approach should be preferable to most other protocols leading to many false positives, causing expensive and lengthy elimination steps to weed out the poor clones.
KW - ELISA
KW - Immunoassay
KW - Microarray
KW - Lab-on-a-chip
KW - Miniaturization
KW - Aautomatisation
KW - HTS
KW - High-throughput
KW - Screening
KW - Fluorescence
KW - Label
KW - Hybridoma
KW - Inhibition
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503361
DO - https://doi.org/10.3390/antib9010001
SN - 2073-4468
VL - 9
IS - 1
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-50336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Döring, Sarah
A1 - Tscheuschner, Georg
A1 - Flemig, Sabine
A1 - Weller, Michael G.
A1 - Konthur, Zoltán
T1 - Cost-Effective Method for Full-Length Sequencing of Monoclonal Antibodies from Hybridoma Cells
N2 - Background: Monoclonal antibodies play an important role in therapeutic and analytical applications. For recombinant expression, the coding sequences of the variable regions of the heavy and light chains are required. In addition, cloning antibody sequences, including constant regions, reduces the impact of hybridoma cell loss and ensures preservation of the naturally occurring full antibody sequence. Method: We combined amplification of IgG antibody variable regions from hybridoma mRNA with an advanced method for fulllength cloning of monoclonal antibodies in a simple two-step workflow. Following Sanger sequencing and evaluation of consensus sequences, the best matching variable, diversity,
and joining (V-(D-)J) gene segments were identified according to identity scores from IgBLAST reference sequences. Simultaneously, the mouse IgG subclass was determined at the DNA level based on isotype-specific sequence patterns in the CH1 domain. Knowing the DNA sequence of V-(D-)J recombination responsible for the complementary determining region 3 (CDR 3), variable region-specific primers were designed and used to amplify the corresponding antibody constant regions. Results: To verify the approach, we applied it to the hybridoma clone BAM-CCMV-29-81 and obtained identical full-length antibody
sequences as with RNA Illumina sequencing. Further validation at the protein level using an established MALDI-TOF MS-fingerprinting protocol showed that five out of six genetically encoded CDR domains of the monoclonal antibody BAM-CCMV-29-81 could be efficiently correlated. Conclusion: This simple, streamlined method enables the cost-effective determination of the full-length sequence of monoclonal antibodies from hybridoma cell lines, with the added benefit of obtaining the DNA sequence of the antibody ready for recombinant expression.
KW - Full-length antibody sequencing
KW - Hybridoma cell loss
KW - MALDI-TOF MS
KW - Immunoglobulin isotyping
KW - RNA Illumina sequencing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639599
DO - https://doi.org/10.3390/antib14030072
SN - 2073-4468
VL - 14
IS - 3
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-63959
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaufmann, Jan Ole
A1 - Brangsch, J.
A1 - Kader, A.
A1 - Saatz, Jessica
A1 - Mangarova, D. B.
A1 - Zacharias, M.
A1 - Kempf, W. E.
A1 - Schwaar, T.
A1 - Ponader, Marco
A1 - Adams, L. C.
A1 - Möckel, J.
A1 - Botnar, R. M.
A1 - Taupitz, M.
A1 - Mägdefessel, L.
A1 - Traub, Heike
A1 - Hamm, B.
A1 - Weller, Michael G.
A1 - Makowski, M. R.
T1 - ADAMTS4-specific MR-probe to assess aortic aneurysms in vivo using synthetic peptide libraries
N2 - The incidence of abdominal aortic aneurysms (AAAs) has substantially increased during the last 20 years and their rupture remains the third most common cause of sudden death in the cardiovascular field after myocardial infarction and stroke. The only established clinical parameter to assess AAAs is based on the aneurysm size. Novel biomarkers are needed to improve the assessment of the risk of rupture. ADAMTS4 (A Disintegrin And Metalloproteinase with ThromboSpondin motifs 4) is a strongly upregulated proteoglycan cleaving enzyme in the unstable course of AAAs. In the screening of a one-bead-one-compound library against ADAMTS4, a low-molecular-weight cyclic peptide is discovered with favorable properties for in vivo molecular magnetic resonance imaging applications. After identification and characterization, it’s potential is evaluated in an AAA mouse model. The ADAMTS4-specific probe enables the in vivo imaging-based prediction of aneurysm expansion and rupture.
KW - Peptide
KW - Peptide library
KW - OBOC library
KW - Combinatorial chemistry
KW - Peptide aptamers
KW - Binding molecule
KW - Affinity
KW - Synthetic peptides
KW - Contrast agent
KW - Magnetic resonance imaging
KW - One-bead-one-compound library
KW - On-chip screening
KW - Lab-on-a-chip
KW - MALDI-TOF MS
KW - SPR
KW - Surface plasmon resonance
KW - Alanine scan
KW - Fluorescence label
KW - MST
KW - Docking
KW - Chelate
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560930
DO - https://doi.org/10.1038/s41467-022-30464-8
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
VL - 13
IS - 1
SP - 1
EP - 18
PB - Springer Nature Limited
CY - Heidelberg
AN - OPUS4-56093
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weller, Michael G.
T1 - A unifying review of bioassay-guided fractionation, effect-directed analysis and related techniques
N2 - The success of modern methods in analytical chemistry sometimes obscures the problem that the ever increasing amount of analytical data does not necessarily give more insight of practical relevance. As alternative approaches, toxicity- and bioactivity-based assays can deliver valuable information about biological effects of complex materials in humans, other species or even ecosystems. However, the observed effects often cannot be clearly assigned to specific chemical compounds. In these cases, the establishment of an unambiguous cause-effect relationship is not possible. Effect-directed analysis tries to interconnect instrumental analytical techniques with a biological/biochemical entity, which identifies or isolates substances of biological relevance. Successful application has been demonstrated in many fields, either as proof-of-principle studies or even for complex samples. This review discusses the different approaches, advantages and limitations and finally shows some practical examples. The broad emergence of effect-directed analytical concepts might lead to a true paradigm shift in analytical chemistry, away from ever growing lists of chemical compounds. The connection of biological effects with the identification and quantification of molecular entities leads to relevant answers to many real life questions.
KW - Toxicity
KW - Drug discovery
KW - Natural products
KW - Environmental analysis
KW - Lead identification
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-262960
DO - https://doi.org/10.3390/s120709181
SN - 1424-8220
VL - 12
IS - 7
SP - 9181
EP - 9209
PB - MDPI
CY - Basel
AN - OPUS4-26296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weller, Michael G.
T1 - Immunoassays and biosensors for the detection of cyanobacterial toxins in water
N2 - Algal blooms are a frequent phenomenon in nearly all kinds of fresh water. Global warming and eutrophication by waste water, air pollution and fertilizers seem to lead to an increased frequency of occurrence. Many cyanobacteria produce hazardous and quite persistent toxins, which can contaminate the respective water bodies. This may limit the use of the raw water for many purposes. The purification of the contaminated water might be quite costly, which makes a continuous and large scale treatment economically unfeasible in many cases. Due to the obvious risks of algal toxins, an online or mobile detection method would be highly desirable. Several biosensor systems have been presented in the literature for this purpose. In this review, their mode of operation, performance and general suitability for the intended purpose will be described and critically discussed. Finally, an outlook on current developments and future prospects will be given.
KW - Algal toxins
KW - Cyanotoxins
KW - Biotoxins
KW - Blue-green algae
KW - Harmful algal blooms
KW - Microcystins
KW - Nodularins
KW - Anatoxin-a
KW - Anatoxin-a(s)
KW - Cylindrospermopsin
KW - Saxitoxins
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-294728
DO - https://doi.org/10.3390/s131115085
SN - 1424-8220
VL - 13
IS - 11
SP - 15085
EP - 15112
PB - MDPI
CY - Basel
AN - OPUS4-29472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hesse, Almut
A1 - Weller, Michael G.
T1 - Protein Quantification by Derivatization-Free High-Performance Liquid Chromatography of Aromatic Amino Acids
N2 - Amino acid analysis is considered to be the gold standard for quantitative peptide and protein analysis. Here, we would like to propose a simple HPLC/UV method based on a reversed-phase separation of the aromatic amino acids tyrosine (Tyr), phenylalanine (Phe), and optionally tryptophan (Trp) without any derivatization. The hydrolysis of the proteins and peptides was performed by an accelerated microwave technique, which needs only 30 minutes. Two internal standard compounds, homotyrosine (HTyr) and 4-fluorophenylalanine (FPhe) were used for calibration. The limit of detection (LOD) was estimated to be 0.05 µM (~10 µg/L) for tyrosine and phenylalanine at 215 nm. The LOD for a protein determination was calculated to be below 16 mg/L (~300 ng BSA absolute). Aromatic amino acid analysis (AAAA) offers excellent accuracy and a precision of about 5% relative standard deviation, including the hydrolysis step. The method was validated with certified reference materials (CRM) of amino acids and of a pure protein (bovine serum albumin, BSA). AAAA can be used for the quantification of aromatic amino acids, isolated peptides or proteins, complex peptide or protein samples, such as serum or milk powder, and peptides or proteins immobilized on solid supports.
KW - Protein analysis
KW - Proteomics
KW - Peptides
KW - Metrology
KW - Certified reference materials
KW - Amino acid analysis
KW - Hydrolysis
KW - Microwave
KW - Tyrosine
KW - Phenylalanine
KW - Tryptophan
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370215
DO - https://doi.org/10.1155/2016/7374316
SN - 2090-0112
SN - 2090-0104
VL - 2016
SP - Article 7374316, 1
EP - 8
PB - Hindawi
CY - Cairo, London, New York
AN - OPUS4-37021
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cervino, C.
A1 - Knopp, D.
A1 - Weller, Michael G.
A1 - Niessner, R.
T1 - Novel Aflatoxin derivatives and protein conjugates
N2 - Aflatoxins, a group of structurally related mycotoxins, are well known for their
toxic and carcinogenic effects in humans and animals. Aflatoxin derivatives and protein
conjugates are needed for diverse analytical applications. This work describes a reliable
and fast synthesis of novel aflatoxin derivatives, purification by preparative HPLC and
characterisation by ESI-MS and one- and two-dimensional NMR. Novel aflatoxin bovine
serum albumin conjugates were prepared and characterised by UV absorption and
MALDI-MS. These aflatoxin protein conjugates are potentially interesting as immunogens
for the generation of aflatoxin selective antibodies with novel specificities.
KW - Aflatoxin
KW - Mycotoxin
KW - Hapten
KW - Protein conjugation
KW - Immunogen
KW - Antigen
KW - Antibody
PY - 2007
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-147572
UR - http://www.mdpi.org/molecules/papers/12030641.pdf
UR - http://www.mdpi.org/molecules/papers/12030641sm.pdf
DO - https://doi.org/10.3390/12030641
SN - 1420-3049
VL - 12
IS - 3
SP - 641
EP - 653
PB - MDPI
CY - Basel
AN - OPUS4-14757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klykov, Oleg
A1 - Weller, Michael G.
T1 - Quantification of N-hydroxysuccinimide and N-hydroxysulfosuccinimide by hydrophilic interaction chromatography (HILIC)
N2 - N-Hydroxysuccinimide (NHS) esters are the most important activated esters used in many different bioconjugation techniques, such as protein labelling by fluorescent dyes and enzymes, surface activation of chromatographic supports, microbeads, nanoparticles, and microarray slides, and also in the chemical synthesis of peptides. Usually, reactions with NHS esters are very reliable and of high yield, however, the compounds are sensitive to air moisture and water traces in solvents. Therefore, the quantification of NHS would be a very helpful approach to identify reagent impurities or degradation of stored NHS esters. No robust and sensitive method for the detection of NHS (or the more hydrophilic sulfo-NHS) has been reported yet. Here, a chromatographic method based on HILIC conditions and UV detection is presented, reaching a detection limit of about 1 mg L-1, which should be sensitive enough for most of the applications mentioned above. Exemplarily, the hydrolytic degradation of a biotin-NHS ester and a purity check of a fluorescent dye NHS ester are shown. An important advantage of this approach is its universality, since not the structurally variable ester compound is monitored, but the constant degradation product NHS or sulfo-NHS, which avoids the necessity to optimize the separation conditions and facilitates calibration considerably.
KW - NHS
KW - Sulfo-NHS
KW - NHS-Ester
KW - Qualitätskontrolle
KW - Reinheitsbestimmung
KW - HPLC
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-337833
DO - https://doi.org/10.1039/c5ay00042d
SN - 1759-9660
SN - 1759-9679
VL - 7
IS - 15
SP - 6443
EP - 6448
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-33783
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Döring, Sarah
T1 - Corundum Particles as Trypsin Carrier for Efficient Protein Digestion
N2 - This dataset contains raw LC–MS/MS files of trypsin-digested NISTmAb acquired on a SCIEX TripleTOF 6600 mass spectrometer in DIA (SWATH) mode for antibody quantification. In addition, it includes MALDI-TOF MS peptide mass fingerprints of trypsin-digested Herceptin as well as reference spectra that can be used for antibody identification using the open-source software ABID 2.0 (https://bam.de/ABID).
The data were generated within a study demonstrating the applicability of corundum-immobilized trypsin for antibody digestion and its suitability for peptide-based LC–MS/MS quantification and MALDI-TOF MS fingerprinting–based antibody identification.
KW - NISTmAb
KW - Herceptin
KW - MALDI-TOF MS peptide mass fingerprint
KW - ABID 2.0
PY - 2025
DO - https://doi.org/10.5281/zenodo.17416536
PB - Zenodo
CY - Geneva
AN - OPUS4-65365
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adams, L. C.
A1 - Brangsch, J.
A1 - Kaufmann, Jan Ole
A1 - Mangarova, D. B.
A1 - Moeckel, J.
A1 - Kader, A.
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Botnar, R. M.
A1 - Hamm, B.
A1 - Makowski, M. R.
A1 - Keller, S.
T1 - Effect of Doxycycline on Survival in Abdominal Aortic Aneurysms in a Mouse Model
N2 - Background. Currently, there is no reliable nonsurgical treatment for abdominal aortic aneurysm (AAA). This study, therefore, investigates if doxycycline reduces AAA growth and the number of rupture-related deaths in a murine ApoE−/− model of AAA and whether gadofosveset trisodium-based MRI differs between animals with and without doxycycline treatment. Methods. Nine ApoE−/− mice were implanted with osmotic minipumps continuously releasing angiotensin II and treated with doxycycline (30 mg/kg/d) in parallel. After four weeks, MRI was performed at 3T with a clinical dose of the albumin-binding probe gadofosveset (0.03 mmol/kg). Results were compared with previously published wild-type control animals and with previously studied ApoE−/− animals without doxycycline treatment. Differences in mortality were also investigated between these groups. Results. In a previous study, we found that approximately 25% of angiotensin II-infused ApoE−/− mice died, whereas in the present study, only one out of 9 angiotensin II-infused and doxycycline-treated ApoE−/− mice (11.1%) died within 4 weeks. Furthermore, doxycycline-treated ApoE−/− mice showed significantly lower contrast-to-noise (CNR) values in MRI compared to ApoE−/− mice without doxycycline treatment. In vivo measurements of relative signal enhancement (CNR) correlated significantly with ex vivo measurements of albumin staining (R2 = 0.58). In addition, a strong visual colocalization of albumin-positive areas in the fluorescence albumin staining with gadolinium distribution in LA-ICP-MS was shown. However, no significant difference in aneurysm size was observed after doxycycline treatment. Conclusion. The present experimental in vivo study suggests that doxycycline treatment may reduce rupture-related deaths in AAA by slowing endothelial damage without reversing aneurysm growth.
KW - Ggadolinium
KW - MRI
KW - Magnetic resonance imaging
KW - Osmotic minipumps
KW - Tetracyclin
KW - Antibiotics
KW - Angiotensin II
KW - LA-ICP-MS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527015
DO - https://doi.org/10.1155/2021/9999847
SP - 9999847
PB - Hindawi
CY - London
AN - OPUS4-52701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weller, Michael G.
T1 - Quality issues of research antibodies
N2 - According to several recent studies, an unexpectedly high number of landmark papers seem to be not reproducible by Independent laboratories. Nontherapeutic antibodies used for research, diagnostic, food analytical, environmental, and other purposes play a significant role in this matter. Although some papers have been published offering suggestions to improve the situation, they do not seem to be comprehensive enough to cover the full complexity of this issue. In addition, no obvious improvements could be noticed in the field as yet. This article tries to consolidate the remarkable variety of conclusions and suggested activities into a more coherent conception. It is concluded that funding agencies and journal publishers need to take first and immediate measures to resolve these problems and lead the way to a more sustainable way of bioanalytical research, on which all can rely with confidence.
KW - reproducibility crisis
KW - irreproducibility
KW - replication
KW - paper retraction
KW - peer reviewimmunochemistry
KW - immunoassay
KW - ligand binding assay
KW - monoclonal antibody
KW - quality control
KW - cross-reactivity
KW - non-specific binding
KW - selectivity
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-356254
DO - https://doi.org/10.4137/ACI.S31614
SN - 1177-3901
VL - 11
SP - 21
EP - 27
PB - Libertas Academica
CY - Auckland, New Zealand
AN - OPUS4-35625
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Filimonova, S. M.
A1 - Melnikov, E. S.
A1 - Kaufmann, Jan Ole
A1 - Shchepochkina, O. Y.
A1 - Eremin, S. A.
A1 - Gravel, I. V.
A1 - Raysyan, Anna
T1 - Exploring the anti‐α‐amylase activity of flavonoid aglycones in fabaceae plant extracts: a combined MALDI‐TOF‐MS and LC–MS/MS approach
N2 - A combination of TLC-bioautography, MALDI-TOF-MS and LC–MS/MS methods was used to identify flavonoids with anti-α-amylase activity in extracts of Lathyrus pratensis L. (herb), L. polyphillus L. (fruits), Thermopsis lanceolata R. Br. (herb) and S. japonica L. (buds). After the TLC-autobiography assay, substances with anti-amylase activity were identified by MALDI-TOF-MS followed by confirmation of the result by LC–MS/MS. Results of the study revealed that the flavonoids apigenin, luteolin, formononetin, genistein and kaempferol display marked anti-α-amylase activity. Formononetin showed the largest activity. Compared with LC–MS/MS, MALDI-TOF-MS is a quick and convenient method; results can be obtained within minutes; and only minor sample amounts are required which allows us to analyse mixtures of substances without preliminary separation. However, the inability to distinguish between isomers is the main limitation of the method.
KW - Enzyme
KW - MALDI-TOF-MS
KW - LC-MS/MS
KW - Massenspektrometrie
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577128
DO - https://doi.org/https://doi.org/10.1111/ijfs.16491
SN - 0950-5423
VL - 58
IS - 7
SP - 3902
EP - 3911
PB - Wiley & Sons
CY - Hoboken, NJ, USA
AN - OPUS4-57712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weller, Michael G.
T1 - The mystery of homochirality on earth
N2 - Homochirality is an obvious feature of life on Earth. On the other hand, extraterrestrial samples contain largely racemic compounds. The same is true for any common organic synthesis. Therefore, it has been a perplexing puzzle for decades how these racemates could have formed enantiomerically enriched fractions as a basis for the origin of homochiral life forms. Numerous hypotheses have been put forward as to how preferentially homochiral molecules could have formed and accumulated on Earth. In this article, it is shown that homochirality of the abiotic organic pool at the time of formation of the first self-replicating molecules is not necessary and not even probable. It is proposed to abandon the notion of a molecular ensemble and to focus on the level of individual molecules. Although the formation of the first self-replicating, most likely homochiral molecule, is a seemingly improbable event, on a closer look, it is almost inevitable that some homochiral molecules have formed simply on a statistical basis. In this case, the non-selective leap to homochirality would be one of the first steps in chemical evolution directly out of a racemic “ocean”. Moreover, most studies focus on the chirality of the primordial monomers with respect to an asymmetric carbon atom. However, any polymer with a minimal size that allows folding to a secondary structure would spontaneously lead to asymmetric higher structures (conformations). Most of the functions of these polymers would be influenced by this inherently asymmetric folding. Furthermore, a concept of physical compartmentalization based on rock nanopores in analogy to nanocavities of digital immunoassays is introduced to suggest that complex cell walls or membranes were also not required for the first steps of chemical evolution. To summarize, simple and universal mechanisms may have led to homochiral self-replicating systems in the context of chemical evolution. A homochiral monomer pool is deemed unnecessary and probably never existed on primordial Earth.
N2 - Homochiralität ist ein offensichtliches Merkmal des Lebens auf der Erde. Andererseits enthalten extraterrestrische Proben überwiegend racemische Verbindungen. Dasselbe gilt für jede gängige organische Synthese. Daher war es jahrzehntelang ein Rätsel, wie diese Racemate enantiomeren-angereicherte Fraktionen als Grundlage für den Ursprung homochiraler Lebensformen bilden konnten. Zahlreiche Hypothesen wurden aufgestellt, wie sich bevorzugt homochirale Moleküle auf der Erde gebildet und angereichert haben könnten. In diesem Artikel wird gezeigt, dass Homochiralität des abiotischen organischen Pools zum Zeitpunkt der Bildung der ersten selbstreplizierenden Moleküle nicht notwendig und nicht einmal wahrscheinlich ist. Es wird vorgeschlagen, die Vorstellung eines molekularen Ensembles aufzugeben und sich auf die Ebene der einzelnen Moleküle zu konzentrieren. Obwohl die Bildung des ersten selbstreplizierenden, höchstwahrscheinlich homochiralen Moleküls ein scheinbar unwahrscheinliches Ereignis ist, ist es bei näherer Betrachtung fast unvermeidlich, dass sich einige homochirale Moleküle einfach auf statistischer Basis gebildet haben. In diesem Fall wäre der nichtselektive Sprung zur Homochiralität einer der ersten Schritte der chemischen Evolution direkt aus einem racemischen "Ozean". Darüber hinaus konzentrieren sich die meisten Studien auf die Chiralität der ursprünglichen Monomere in Bezug auf ein asymmetrisches Kohlenstoffatom. Jedes Polymer mit einer Mindestgröße, die eine Faltung zu einer Sekundärstruktur erlaubt, würde jedoch spontan zu asymmetrischen höheren Strukturen (Konformationen) führen. Die meisten Funktionen dieser Polymere würden durch diese inhärent asymmetrische Faltung beeinflusst. Darüber hinaus wird ein Konzept der physikalischen Kompartimentierung auf der Basis von Gesteinsnanoporen in Analogie zu den Nanokavitäten digitaler Immunoassays vorgestellt, das darauf hindeutet, dass auch für die ersten Schritte der chemischen Evolution keine komplexen Zellwände oder Membranen notwendig waren. Zusammenfassend lässt sich sagen, dass einfache und universelle Mechanismen zu homochiralen selbstreplizierenden Systemen im Rahmen der chemischen Evolution geführt haben könnten. Ein homochiraler Monomerpool wird als unnötig angesehen, welcher auf der Urerde wahrscheinlich nie existiert hat.
KW - Chemical evolution
KW - Enantiomeric excess ee
KW - Chirality
KW - Racemate
KW - Folding chirality
KW - Self-assembly
KW - self-replication
KW - Single molecule
KW - Prebiotic chemistry
KW - Protein folding
KW - Peptide folding
KW - Proteinoid
KW - Conformation
KW - Segregation
KW - Compartmentalization
KW - Digital immunoassay
KW - Porous rock
KW - Miller and Urey
KW - Primordial soup
KW - Murchison meteorite
KW - Micrometeorites
KW - Tholins
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598349
DO - https://doi.org/10.3390/life14030341
SN - 2075-1729
VL - 14
IS - 3
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-59834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frechilla, A.
A1 - Martínez, E.
A1 - del Moral, J.
A1 - López-Santos, C.
A1 - Frechilla, J.
A1 - Nuñez-Gálvez, F.
A1 - López-Flores, V.
A1 - de la Fuente, G.F.
A1 - Hülagü, Deniz
A1 - Bonse, Jörn
A1 - González-Elipe, A.R.
A1 - Borrás, A.
A1 - Angurel, L.A.
T1 - Influence of near-edge Laser-Induced Periodic Surface Structures (LIPSS) on the electrical properties of fs-laser-machined ITO microcircuits
N2 - Scalable, cost-effective methods for processing transparent electrodes at the microscale are pivotal to advancing in electrochemistry, optoelectronics, microfluidics, and energy harvesting. In these fields, the precise fabrication of micrometric circuits and patterns plays a critical role in determining device performance, material compatibility, and integration with added-value substrates. In this context, Laser Subtractive Manufacturing stands out as a suitable microfabrication technique for its adaptability to diverse materials and complex configurations, as well as its straightforward scalability, affordability, and eco-friendly nature. However, a challenge in micromachining metals and metal oxides is the inherent formation of Laser-Induced Periodic Surface Structures (LIPSS), which can significantly impair electrical conductivity, particularly when circuit dimensions fall within the micrometer range. Herein, we investigate the micromachining of electrical microcircuits using ultrashort pulse laser systems applied to transparent indium tin oxide (ITO) thin films. We analyze the formation of LIPSS at the edges of the micromachined regions associated with the Gaussian distribution of the energy within the laser spot, and the impact of these structures on the electrical properties of the circuits. Thus, we systematically evaluate the influence of LIPSS orientation and periodicity by fabricating various circuit patterns using femtosecond lasers at green (515 nm) and ultraviolet (UV) (343 nm) wavelengths. A correlation between electrical resistivity measurements and microstructure analysis, as determined by field emission scanning electron and transmission electron microscopy, reveals distinct effects of the formed nanostructures depending on the laser source and its polarization. For the green wavelength, the edge side regions where LIPSS are oriented perpendicular to the ITO track exhibit a resistance higher by a factor just above two compared to those where LIPSS are parallel. Additionally, UV laser processing results in a pronounced reduction of ITO thickness at the boundary between the LIPSS region and the substrate. The mechanisms for the formation of LIPSS with both wavelengths are also discussed. Furthermore, we have determined that in narrow conductive tracks with a width ranging from 6 to 8 µm, the impact of LIPSS is particularly significant because the LIPSS structured region occupies a dominant fraction of the total width.
KW - ITO
KW - Laser-induced periodic surface structures (LIPSS)
KW - Laser subtractive manufacturing
KW - fs-laser processing
KW - Electrical properties
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655921
DO - https://doi.org/10.1016/j.apsusc.2026.166415
SN - 0169-4332
VL - 731
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reinmuth-Selzle, K.
A1 - Tchipilov, Teodor
A1 - Backes, A. T.
A1 - Tscheuschner, Georg
A1 - Tang, K.
A1 - Ziegler, K.
A1 - Lucas, K.
A1 - Pöschl, U.
A1 - Fröhlich-Nowoisky, J.
A1 - Weller, Michael G.
T1 - Determination of the protein content of complex samples by aromatic amino acid analysis, liquid chromatography-UV absorbance, and colorimetry
N2 - Fast and accurate determination of the protein content of a sample is an important and non-trivial task of many biochemical, biomedical, food chemical, pharmaceutical, and environmental research activities. Different methods of total protein determination are used for a wide range of proteins with highly variable properties in complex matrices. These methods usually work reasonably well for proteins under controlled conditions, but the results for non-standard and complex samples are often questionable. Here, we compare new and well-established methods, including traditional amino acid analysis (AAA), aromatic amino acid analysis (AAAA) based on the amino acids phenylalanine and tyrosine, reversed-phase liquid chromatography of intact proteins with UV absorbance measurements at 220 and 280 nm (LC-220, LC-280), and colorimetric assays like Coomassie Blue G-250 dye-binding assay (Bradford) and bicinchoninic acid (BCA) assay. We investigated different samples, including proteins with challenging properties, chemical modifications, mixtures, and complex matrices like air particulate matter and pollen extracts. All methods yielded accurate and precise results for the protein and matrix used for calibration. AAA, AAAA with fluorescence detection, and the LC-220 method yielded robust results even under more challenging conditions (variable analytes and matrices). These methods turned out to be well-suited for reliable determination of the protein content in a wide range of samples, such as air particulate matter and pollen.
KW - Air particulate matter
KW - Aromatic amino acid analysis
KW - Atmospheric aerosol
KW - Chemical protein modification
KW - Derivatization
KW - Nitration
KW - Nitrotyrosine
KW - LC-UV absorbance
KW - Pollen extract
KW - Protein quantification
KW - Protein test
KW - Kjeldahl
KW - Tyrosine
KW - Phenylalanine
KW - Hydrolysis
KW - Bradford
KW - BCA test
KW - 280 nm
KW - Air filter samples
KW - Fluorescence
KW - HPLC
KW - Chromatography
KW - Protein content
KW - 150th anniversary of BAM
KW - Topical collection: Analytical Methods and Applications in the Materials and Life Sciences
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545924
UR - https://pubmed.ncbi.nlm.nih.gov/35320366/
DO - https://doi.org/10.1007/s00216-022-03910-1
SP - 1
EP - 14
PB - Springer Nature Limited
CY - New York, Heidelberg
AN - OPUS4-54592
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Keller, S.
A1 - Borde, T.
A1 - Brangsch, J.
A1 - Reimann, C.
A1 - Kader, A.
A1 - Schulze, D.
A1 - Buchholz, R.
A1 - Kaufmann, Jan Ole
A1 - Karst, U.
A1 - Schellenberger, E.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Assessment of the hepatic tumor extracellular matrix using elastin‑specific molecular magnetic resonance imaging in an experimental rabbit cancer model
N2 - To investigate the imaging performance of an elastin-specific molecular magnetic resonance imaging (MRI) probe with respect to the extracellular matrix (ECM) in an experimental hepatic cancer model. Twelve rabbits with hepatic VX2 tumors were examined using 3 T MRI 14, 21, and 28 days after tumor implantation for two subsequent days (gadobutrol, day 1; elastin-specific probe, day 2). The relative enhancement (RE) of segmented tumor regions (central and margin) and the peritumoral matrix was calculated using pre-contrast and delayed-phase T1w sequences. MRI measurements were correlated to histopathology and element-specific and spatially resolved mass spectrometry (MS). Mixed-model analysis was performed to assess the performance of the elastin-specific probe. In comparison to gadobutrol, the elastin probe showed significantly stronger RE, which was pronounced in the tumor margin (day 14–28: P ≤ 0.007). In addition, the elastin probe was superior in discriminating between tumor regions (χ2(4) = 65.87; P < 0.001). MRI-based measurements of the elastin probe significantly correlated with the ex vivo elastinstain (R = .84; P <0 .001) and absolute gadolinium concentrations (ICP-MS: R = .73, P <0 .01). LA-ICP-MS imaging confirmed the colocalization of the elastin-specific probe with elastic fibers. Elastin-specific molecular MRI is superior to non-specific gadolinium-based contrast agents in imaging the ECM of hepatic tumors and the peritumoral tissue.
KW - Elastin-specific molecular agent
KW - Extracellular matrix
KW - Hepatocellular carcinoma
KW - Inductively coupled plasma mass spectroscopy
KW - Laser ablation-inductively coupled plasma-mass spectrometry
KW - Magnetic resonance imaging
KW - MR imaging
KW - ESMA
KW - Gadolinium
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517360
DO - https://doi.org/10.1038/s41598-020-77624-8
VL - 10
IS - 1
SP - 20785
PB - Nature
AN - OPUS4-51736
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lucassen, F.
A1 - Pritzkow, Wolfgang
A1 - Rosner, M.
A1 - Sepulveda, F.
A1 - Vasquez, P.
A1 - Wilke, H.
A1 - Kasemann, S. A.
T1 - The stable isotope composition of nitrogen and carbon and elemental contents in modern and fossil seabird guano from Northern Chile – Marine sources and diagenetic effects
N2 - Seabird excrements (guano) have been preserved in the arid climate of Northern Chile since at least the Pliocene. The deposits of marine organic material in coastal areas potentially open a window into the present and past composition of the coastal ocean and its food web. We use the stable isotope composition of nitrogen and carbon as well as element contents to compare the principal prey of the birds, the Peruvian anchovy, with the composition of modern guano. We also investigate the impact of diagenetic changes on the isotopic composition and elemental contents of the pure ornithogenic sediments, starting with modern stratified deposits and extending to fossil guano. Where possible, 14C systematics is used for age information. The nitrogen and carbon isotopic composition of the marine prey (Peruvian anchovy) of the birds is complex as it shows strong systematic variations with latitude. The detailed study of a modern profile that represents a few years of guano deposition up to present reveals systematic changes in nitrogen and carbon isotopic composition towards heavier values that increase with age, i.e. depth. Only the uppermost, youngest layers of modern guano show compositional affinity to the prey of the birds. In the profile, the simultaneous loss of nitrogen and carbon occurs by degassing, and non-volatile elements like phosphorous and calcium are passively enriched in the residual guano. Fossil guano deposits are very low in nitrogen and low in carbon contents, and show very heavy nitrogen isotopic compositions. One result of the study is that the use of guano for tracing nitrogen and carbon isotopic and elemental composition in the marine food web of the birds is restricted to fresh material. Despite systematic changes during diagenesis, there is little promise to retrieve reliable values of marine nitrogen and carbon signatures from older guano. However, the changes in isotopic composition from primary marine nitrogen isotopic signatures towards very heavy values generate a compositionally unique material. These compositions trace the presence of guano in natural ecosystems and its use as fertilizer in present and past agriculture.
KW - Isotope ratio
KW - VPDB
KW - Fishmeal
KW - Elemental analyser
KW - Vario EL III
KW - Casein standard
KW - ICP-OES
KW - Accelerator mass spectrometry
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-407911
DO - https://doi.org/10.1371/journal.pone.0179440
SN - 1932-6203
VL - 12
IS - 6
SP - Article e0179440, 1
EP - 25
PB - PLOS
CY - San Francisco, California, US
AN - OPUS4-40791
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, F.
A1 - Lakey, P. S. J.
A1 - Berkemeier, T.
A1 - Tong, H.
A1 - Kunert, A. T.
A1 - Meusel, H.
A1 - Cheng, Y.
A1 - Su, H.
A1 - Fröhlich-Nowoisky, J.
A1 - Lai, S.
A1 - Weller, Michael G.
A1 - Shiraiwa, M.
A1 - Pöschl, U.
A1 - Kampf, C. J.
T1 - Atmospheric protein chemistry influenced by anthropogenic air pollutants: nitration and oligomerization upon exposure to ozone and nitrogen dioxide
N2 - The allergenic potential of airborne proteins may be enhanced via post-translational modification induced by air pollutants like ozone (O3) and nitrogen dioxide (NO2). The molecular mechanisms and kinetics of the chemical modifications that enhance the allergenicity of proteins, however, are still not fully understood. Here, protein tyrosine nitration and oligomerization upon simultaneous exposure of O3 and NO2 were studied in coated-wall flow-tube and bulk solution experiments under varying atmospherically relevant conditions (5–200 ppb O3, 5–200 ppb NO2, 45–96% RH), using bovine serum albumin as a model protein. Generally, more tyrosine residues were found to react via the nitration pathway than via the oligomerization pathway. Depending on reaction conditions, oligomer mass fractions and nitration degrees were in the ranges of 2.5–25% and 0.5–7%, respectively. The experimental results were well reproduced by the kinetic multilayer model of aerosol surface and bulk chemistry (KM-SUB). The extent of nitration and oligomerization strongly depends on relative humidity (RH) due to moisture-induced phase transition of proteins, highlighting the importance of cloud processing conditions for accelerated protein chemistry. Dimeric and nitrated species were major products in the liquid phase, while protein oligomerization was observed to a greater extent for the solid and semi-solid phase states of proteins. Our results show that the rate of both processes was sensitive towards ambient ozone concentration but rather insensitive towards different NO2 levels. An increase of tropospheric ozone concentrations in the Anthropocene may thus promote pro-allergic protein modifications and contribute to the observed increase of allergies over the past decades.
KW - Oxidation
KW - Nitration
KW - Cross-linking
KW - Ozone
KW - Nitrogen dioxide
KW - Dimer
KW - Air pollution
KW - Diesel
KW - Aeroallergens
KW - Pollen
KW - Tyrosine
KW - Nitrotyrosine
KW - BSA
KW - Albumin
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418482
DO - https://doi.org/10.1039/c7fd00005g
SN - 1359-6640
VL - 200
SP - 413
EP - 427
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-41848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Weller, Michael G.
T1 - Referee Report 06 March 2017
N2 - This article is a valuable and welcome contribution to the ongoing discussion of antibody quality. The suggestion of a two-tier approach is helpful to distinguish between simple descriptive data and the validation of an antibody for a specified application.
KW - Antibody
KW - Validation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393333
UR - https://f1000research.com/articles/6-161/v1#referee-response-20349
DO - https://doi.org/10.5256/f1000research.11700.r20349
SN - 2046-1402
SP - 6
EP - 7
PB - F1000 Research Ltd.
CY - London
AN - OPUS4-39333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, F.
A1 - Lai, S.
A1 - Tong, H.
A1 - Lakey, P. S. J.
A1 - Shiraiwa, M.
A1 - Weller, Michael G.
A1 - Pöschl, U.
A1 - Kampf, C. J.
T1 - Release of free amino acids upon oxidation of peptides and proteins by hydroxyl radicals
N2 - Hydroxyl radical-induced oxidation of proteins and peptides can lead to the cleavage of the peptide, leading to a release of fragments. Here, we used high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and pre-column online ortho-phthalaldehyde (OPA) derivatization-based amino acid analysis by HPLC with diode array detection and fluorescence detection to identify and quantify free amino acids released upon oxidation of proteins and peptides by hydroxyl radicals. Bovine serum albumin (BSA), ovalbumin (OVA) as model proteins, and synthetic tripeptides (comprised of varying compositions of the amino acids Gly, Ala, Ser, and Met) were used for reactions with hydroxyl radicals, which were generated by the Fenton reaction of iron ions and hydrogen peroxide. The molar yields of free glycine, aspartic acid, asparagine, and alanine per peptide or protein varied between 4 and 55%. For protein oxidation reactions, the molar yields of Gly (∼32-55% for BSA, ∼10-21% for OVA) were substantially higher than those for the other identified amino acids (∼5-12% for BSA, ∼4-6% for OVA). Upon oxidation of tripeptides with Gly in C-terminal, mid-chain, or N-terminal positions, Gly was preferentially released when it was located at the C-terminal site. Overall, we observe evidence for a site-selective formation of free amino acids in the OH radical-induced oxidation of peptides and proteins, which may be due to a reaction pathway involving nitrogen-centered radicals.
KW - Peptides
KW - Proteins
KW - Oxidation
KW - Hydroxyl radicals
KW - LC-MS
KW - Amino acid analysis
KW - Bovine serum albumin
KW - Ovalbumin
KW - Tripeptides
KW - Ortho-Phthalaldehyde
KW - AAA
KW - Degradation
KW - Fragmentation
KW - Mechanism
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-398714
UR - http://link.springer.com/article/10.1007%2Fs00216-017-0188-y
DO - https://doi.org/10.1007/s00216-017-0188-y
SN - 1618-2650
SN - 1618-2642
VL - 409
IS - 9
SP - 2411
EP - 2420
PB - Springer
CY - Heidelberg
AN - OPUS4-39871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scherz, Franziska
A1 - Krop, U.
A1 - Monks, K.
A1 - Weller, Michael G.
T1 - Antikörperreinigung mit Glasmonolithen - Vereinfachung von Affinitätstrennungen mit HPLC-Systemen
N2 - Druckstabile Glasmonolithen ermöglichen eine schnelle und unkomplizierte Reinigung von Antikörpern, z.B. aus Serum oder Zellkulturüberständen. Die sehr gute Regenerierbarkeit lässt eine lange Lebensdauer der Säulen erwarten, was die
Kosten pro Probe niedrig hält.
KW - Borosilicatglas
KW - Immunglobuline
KW - IgG
KW - Serum
KW - Plasma
KW - Protein A
KW - Protein G
KW - Affinitätschromatographie
KW - Agarose
KW - Carrier-Material
KW - Stationäre Phase
KW - Immobilisierung
KW - Highspeed
KW - Trennung
KW - Reinigung
KW - Downstream Processing
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-445330
UR - http://www.git-labor.de/forschung/materialien/antikoerperreinigung-mit-glasmonolithen
SN - 0016-3538
VL - 62
IS - 3
SP - 24
EP - 25
PB - Wiley-VCH Verlag GmbH & Co. KGaA
CY - Weinheim
AN - OPUS4-44533
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Weller, Michael G.
T1 - Interview with Dr Michael G. Weller
N2 - This author interview is by Dr Michael G. Weller, Head of Division 1.5 Protein Analysis at Federal Institute for Materials Research and Testing (BAM). BAM (www.bam.de/en) is a senior scientific and technical institute with responsibility to the German Federal Ministry for Economic Affairs and Energy. Dr Weller's review paper, Quality issues of research antibodies is available for download in Analytical Chemistry Insights.
KW - Antibodies
KW - Quality
KW - Reproducibility
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-392326
UR - http://insights.sagepub.com/la_press_news.php?pa=view&news_item_id=4025
SP - 1
PB - SAGE
CY - London
AN - OPUS4-39232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altmann, Korinna
A1 - Portela, Raquel
A1 - Barbero, Francesco
A1 - Breuninger, Esther
A1 - Camassa, Laura Maria Azzurra
A1 - Velickovic, Tanja Cirkovic
A1 - Charitidis, Costas
A1 - Costa, Anna
A1 - Fadda, Marta
A1 - Fengler, Petra
A1 - Fenoglio, Ivana
A1 - Giovannozzi, Andrea M.
A1 - Haugen, Øyvind Pernell
A1 - Kainourgios, Panagiotis
A1 - von der Kammer, Frank
A1 - Kirchner, Markus J.
A1 - Lomax-Vogt, Madeleine
A1 - Lujic, Tamara
A1 - Milczewski, Frank
A1 - Moussawi, Mhamad Aly
A1 - Ortelli, Simona
A1 - Parac-Vogt, Tatjana N.
A1 - Potthoff, Annegret
A1 - Reinosa, Julian J.
A1 - Röschter, Sophie
A1 - Sacco, Alessio
A1 - Wimmer, Lukas
A1 - Zanoni, Ilaria
A1 - Dailey, Lea Ann
T1 - Characterizing nanoplastic suspensions of increasing complexity: Inter-laboratory comparison of size measurements using dynamic light scattering
N2 - Understanding the potential human health risks associated with micro- and nanoplastic exposure is currently a priority research area. Nanoplastic toxicity studies are complicated by the lack of available, well-characterized test and reference materials. Further, many nanoplastic test materials are inherently more polydisperse and heterogenous in shape compared to polystyrene beads, making accurate and representative size distribution measurements particularly challenging. The aim of this study was to conduct an inter-laboratory comparison of dynamic light scattering measurements, the most commonly used particle sizing method for nanomaterials. Using a published standard operating procedure, size measurements in water and a standardized cell culture medium (CCM) were generated for spherical, carboxy-functionalized polystyrene nanoparticles (PS-COOH; 50 nm; benchmark material), and for increasingly complex in-house produced spherical poly(ethylene terephthalate) (nanoPET) and irregular shaped polypropylene (nanoPP) test materials. The weighted mean of hydrodynamic diameters of PS-COOH dispersed in water (55 ± 5 nm) showed moderate variation between labs (coefficient of variation, CV = 8.2%) and were similar to literature reports. Measurements of nanoPET (82 ± 6 nm) and nanoPP (182 ± 12 nm) in water exhibited similar CV values (nanoPET: 7.3% and nanoPP; 6.8%). Dispersion of PS-COOH and nanoPET in CCM increased the CV to 15.1 and 14.2%, respectively, which is lower than literature reports (CV = 30%). We conclude with a series of practical recommendations for robust size measurements of nanoplastics in both water and complex media highlighting that strict adherence to a standard operating procedure is required to prevent particle agglomeration in CCM
KW - Nanoplastics
KW - Reference materials
KW - Polypropylene
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644571
DO - https://doi.org/10.1039/d5en00645g
SN - 2051-8153
SP - 1
EP - 15
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64457
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolar, Tomislav
A1 - Alić, Jasna
A1 - Casali, Lucia
A1 - Gugin, Nikita
A1 - Baláž, Matej
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
ED - Stolar, Tomislav
T1 - Mechanochemistry: Looking back and ahead
N2 - Starting with the discovery of fire and the preparation of food in prehistoric times, mechanochemistry is the oldest form of chemistry that humans have controlled. Mechanochemical practices, such as grinding with a mortar and pestle, continued into the Middle Ages until dedicated scientific studies began in the 19th century. Since then,research in mechanochemistry has shown that many chemicalreactions can be performed via mechanical force without or with small amounts of solvent. Besides being time, material, and energy efficient, mechanochemical reactions often yield products that differ from those obtained in solution. Therefore, not only is mechanochemistry greener and more sustainable than conventional solution chemistry, but it also has the added value of providing new reactivity and selectivity. This is especially important today, when chemists need to invent high-performance materials, intermediates, and products with the use of sustainable feedstocks and develop environmental remediation pathways. At the same time, time-resolved in situ monitoring and computational modeling are necessary for addressing fundamental questions about the atomistic, molecular, and electronic nature of mechanochemical reactivity. Integrating digitalization, robotics, and artificial intelligence tools promises to increase the reproducibility and scalability of mechanochemical processes. Further evolution of mechanochemistry is expected to have a transformative effect on the chemical industry.
KW - Mechanochemistry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653962
DO - https://doi.org/10.1016/j.chempr.2025.102880
SN - 2451-9294
VL - 12
IS - 2
SP - 1
EP - 27
PB - Elsevier BV
AN - OPUS4-65396
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Casali, Lucia
A1 - Carta, Maria
A1 - Michalchuk, Adam
A1 - Delogu, Francesco
A1 - Emmerling, Franziska
T1 - Kinetics of the mechanically induced ibuprofen–nicotinamide co-crystal formation by in situ X-ray diffraction
N2 - Mechanochemistry is drawing attention from the pharmaceutical industry given its potential for sustainable material synthesis and manufacture. Scaling mechanochemical processes to industrial level remains a challenge due to an incomplete understanding of their underlying mechanisms. We here show how time-resolved in situ powder X-ray diffraction data, coupled with analytical kinetic modelling, provides a powerful approach to gain mechanistic insight into mechanochemical reactions. By using the ibuprofen–nicotinamide co-crystal mechanosynthesis as a benchmark system, we investigate the behaviour of the solids involved and identify the factors that promote the reaction. As mechanochemical mechanisms become increasingly clear, it promises to become a breakthrough in the industrial preparation of advanced pharmaceuticals.
KW - Mechanochemistry
KW - Kinetics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608820
DO - https://doi.org/10.1039/D4CP01457J
SN - 1463-9084
VL - 26
SP - 22041
EP - 22048
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-60882
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Trestman, M.
A1 - Rudic, S.
A1 - Portius, P.
A1 - Fincham, P.
A1 - Pulham, C.
A1 - Morrison, C.
T1 - Predicting the reactivity of energetic materials: an ab initio multi-phonon approach
N2 - The ease with which an energetic material (explosives, propellants, and pyrotechnics) can be initiated is a critical parameter to assess their safety and application. Impact sensitivity parameters are traditionally derived experimentally, at great cost and risk to safety. In this work we explore a fully ab initio Approach based on concepts of vibrational energy transfer to predict impact sensitivities for a series of chemically, structurally and energetically diverse molecular materials. The quality of DFT calculations is assessed for a subset of the materials by comparison with experimental inelastic neutron scattering spectra (INS). A variety of models are considered, including both qualitative and quantitative analysis of the vibrational spectra. Excellent agreement against experimental impact sensitivity is achieved by consideration of a multi-phonon ladder-type up-pumping mechanism that includes both overtone and combination pathways, and is improved further by the added consideration of temperature. This fully ab initio approach not only permits ranking of energetic materials in terms of their impact sensitivity but also provides a tool to guide the targeted design of advanced energetic compounds with tailored properties.
KW - Energetic Materials
KW - Prediction
KW - Density Functional Theory
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489328
DO - https://doi.org/10.1039/c9ta06209b
VL - 7
IS - 33
SP - 19539
EP - 19553
PB - RSC
AN - OPUS4-48932
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, B.
A1 - Meyer, T.
A1 - Sieg, H.
A1 - Kästner, Claudia
A1 - Reichardt, P.
A1 - Tentschert, J.
A1 - Jungnickel, H.
A1 - Estrela-Lopis, I.
A1 - Burel, A.
A1 - Chevance, S.
A1 - Gauffre, F.
A1 - Jalili, P.
A1 - Meijer, J.
A1 - Böhmert, L.
A1 - Braeuning, A.
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
A1 - Fessard, V.
A1 - Laux, P.
A1 - Lampen, A.
A1 - Luch, A.
T1 - Characterization of aluminum, aluminum oxide and titanium dioxide nanomaterials using a combination of methods for particle surface and size analysis
N2 - The application of appropriate analytical techniques is essential for nanomaterial (NM) characterization. In this study, we compared different analytical techniques for NM analysis. Regarding possible adverse health effects, ionic and particulate NM effects have to be taken into account. As NMs behave quite differently in physiological media, special attention was paid to techniques which are able to determine the biosolubility and complexation behavior of NMs. Representative NMs of similar size were selected: aluminum (Al0) and aluminum oxide (Al2O3), to compare the behavior of metal and metal oxides. In addition, titanium dioxide (TiO2) was investigated. Characterization techniques such as dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were evaluated with respect to their suitability for fast characterization of nanoparticle dispersions regarding a particle's hydrodynamic diameter and size distribution. By application of inductively coupled plasma mass spectrometry in the single particle mode (SP-ICP-MS), individual nanoparticles were quantified and characterized regarding their size. SP-ICP-MS measurements were correlated with the information gained using other characterization techniques, i.e. transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The particle surface as an important descriptor of NMs was analyzed by X-ray diffraction (XRD). NM impurities and their co-localization with biomolecules were determined by ion beam microscopy (IBM) and confocal Raman microscopy (CRM). We conclude advantages and disadvantages of the different techniques applied and suggest options for their complementation. Thus, this paper may serve as a practical guide to particle characterization techniques.
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447057
DO - https://doi.org/10.1039/C8RA00205C
SN - 2046-2069
VL - 8
IS - 26
SP - 14377
EP - 14388
PB - The Royal Society of Chemistry
AN - OPUS4-44705
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santos de Freitas, M.
A1 - Araghi, R. R.
A1 - Brandenburg, E.
A1 - Leiterer, Jork
A1 - Emmerling, Franziska
A1 - Folmert, K.
A1 - Gerling-Driessen, U. I. M.
A1 - Bardiaux, B.
A1 - Böttcher, C.
A1 - Pagel, K.
A1 - Diehl, A.
A1 - v. Berlepsch, H.
A1 - Oschkinat, H.
A1 - Koksch, B.
T1 - The protofilament architecture of a de novo designed coiled coil-based amyloidogenic peptide
N2 - Amyloid fibrils are polymers formed by proteins under specific conditions and in many cases they are related to pathogenesis, such as Parkinson’s and Alzheimer’s diseases. Their hallmark is the presence of a β-sheet structure. High resolution structural data on these systems as well as information gathered from multiple complementary analytical techniques is needed, from both a fundamental and a pharmaceutical perspective. Here, a previously reported de novo designed, pH-switchable coiled coil-based peptide that undergoes structural transitions resulting in fibril formation under physiological conditions has been exhaustively characterized by transmission electron microscopy (TEM), cryo-TEM, atomic force microscopy (AFM), wide-angle X-ray scattering (WAXS) and solid-state NMR (ssNMR). Overall, a unique 2-dimensional carpet-like assembly composed of large coexisiting ribbon-like, tubular and funnel-like structures with a clearly resolved protofilament substructure is observed. Whereas electron microscopy and scattering data point somewhat more to a hairpin model of β-fibrils, ssNMR data obtained from samples with selectively labelled peptides are in agreement with both, hairpin structures and linear arrangements.
KW - Amyloid
KW - Elektronenmikroskopie
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458713
UR - https://www.sciencedirect.com/science/article/pii/S1047847718301333
DO - https://doi.org/10.1016/j.jsb.2018.05.009
SN - 1047-8477
VL - 203
IS - 3
SP - 263
EP - 272
PB - Elsevier
AN - OPUS4-45871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seidel, R.
A1 - Kraffert, K.
A1 - Kabelitz, Anke
A1 - Pohl, M.N.
A1 - Kraehnert, R.
A1 - Emmerling, Franziska
A1 - Winter, B.
T1 - Detection of the electronic structure of iron-(III)-oxo oligomers forming in aqueous solutions
N2 - The nature of the small iron-oxo oligomers in iron-(III) aqueous solutions has a determining effect on the chemical processes that govern the formation of nanoparticles in aqueous phase. Here we report on a liquid-Jet photoelectron-spectroscopy experiment for the investigation of the electronic structure of the occurring iron-oxo oligomers in FeCl3 aqueous solutions. The only iron species in the as-prepared 0.75 M solution are Fe3+ monomers. Addition of NaOH initiates Fe3+ hydrolysis which is followed by the formation of iron-oxo oligomers. At small enough NaOH concentrations, corresponding to approximately [OH]/[Fe] = 0.2–0.25 ratio, the iron oligomers can be stabilized for several hours without engaging in further aggregation. Here, we apply a combination of non-resonant as well as iron 2p and Oxygen 1s resonant photoelectron spectroscopy from a liquid microjet to detect the electronic structure of the occurring species. Specifically, the oxygen 1s partial electron yield X-ray absorption (PEY-XA) spectra are found to exhibit a peak well below the onset of liquid water and OH (aq) absorption. The iron 2p absorption gives rise to signal centered between the main absorption bands typical for aqueous Fe3+. Absorption bands in both PEY-XA spectra are found to correlate with an enhanced photoelectron Peak near 20 eV binding energy, which demonstrates the sensitivity of resonant photoelectron (RPE) spectroscopy to mixing between iron and ligand orbitals. These various signals from the iron-oxo oligomers exhibit Maximum intensity at [OH]/[Fe] = 0.25 ratio. For the same ratio, we observe changes in the pH as well as in complementary Raman spectra, which can be assigned to the Transition from monomeric to oligomeric species. At approximately [OH]/[Fe] = 0.3 we begin to observe particles larger than 1 nm in radius, detected by small-angle X-ray scattering.
KW - Iron-oxo oligomers
KW - XPS
KW - Electronic structure
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-433468
DO - https://doi.org/10.1039/c7cp06945f
SN - 1463-9076
SN - 1463-9084
VL - 19
IS - 48
SP - 32226
EP - 32234
AN - OPUS4-43346
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilke, Manuel
A1 - Kabelitz, Anke
A1 - Gorelik, T. E.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Reinholz, Uwe
A1 - Kolb, U.
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - The crystallisation of copper(II) phenylphosphonates
N2 - The crystal structures and syntheses of four different copper(II) phenylphosphonates, the monophenylphosphonates α-, β-, and γ-Cu(O3PC6H5)·H2O (α-CuPhPmH (1) β-CuPhPmH (2) and γ-CuPhPmH (3)), and the diphosphonate Cu(HO3PC6H5)2·H2O (CuPhP2mH (4)), are presented. The compounds were synthesized from solution at room temperature, at elevated temperature, under hydrothermal conditions, and mechanochemical conditions. The structures of α-CuPhPmH (1) and CuPhP2mH (4) were solved from powder X-ray diffraction data. The structure of β-CuPhPmH (2) was solved by single crystal X-ray analysis. The structures were validated by extended X-ray absorption fine structure (EXAFS) and DTA analyses. Disorder of the crystal structure was elucidated by electron diffraction. The relationship between the compounds and their reaction pathways were investigated by in situ synchrotron measurements.
KW - Mechanochemistry
KW - Metal phosphonate
KW - In situ
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-384217
DO - https://doi.org/10.1039/C6DT02904C
SN - 1477-9226
SN - 1477-9234
VL - 45
IS - 43
SP - 17453
EP - 17463
PB - The Royal Society of Chemistry
AN - OPUS4-38421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kulla, Hannes
A1 - Greiser, Sebastian
A1 - Benemann, Sigrid
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - In Situ Investigation of a Self-Accelerated Cocrystal Formation by Grinding Pyrazinamide with Oxalic Acid
N2 - A new cocrystal of pyrazinamide with oxalic acid was prepared mechanochemically and characterized by PXRD, Raman spectroscopy, solid-state NMR spectroscopy, DTA-TG, and SEM. Based on powder X-ray diffraction data the structure was solved. The formation pathway of the reaction was studied in situ using combined synchrotron PXRD and Raman spectroscopy. Using oxalic acid dihydrate the initially neat grinding turned into a rapid self-accelerated liquid-assisted grinding process by the release of crystallization water. Under these conditions, the cocrystal was formed directly within two minutes.
KW - in situ
KW - cocrystal
KW - mechanochemistry
KW - pyrazinamide
KW - hydrate
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372357
DO - https://doi.org/10.3390/molecules21070917
SN - 1420-3049
VL - 21
IS - 7
SP - Article 917, 1
EP - 9
AN - OPUS4-37235
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Franziska
A1 - Wenzel, Klaus-Jürgen
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - Quantitative determination of activation energies in mechanochemical reactions
N2 - Mechanochemical reactions often result in 100% yields of single products, making purifying procedures obsolete. Mechanochemistry is also a sustainable and eco-friendly method. The ever increasing interest in this method is contrasted by a lack in mechanistic understanding of the mechanochemical reactivity and selectivity. Recent in situ investigations provided direct insight into formation pathways. However, the currently available theories do not predict temperature T as an influential factor. Here, we report the first determination of an apparent activation energy for a mechanochemical reaction. In a temperaturedependent in situ study the cocrystallisation of ibuprofen and nicotinamide was investigated as a model system. These experiments provide a pivotal step towards a comprehensive understanding of milling reaction mechanisms.
KW - Mechanochemistry
KW - Cocrystal
KW - Activation energy
KW - Milling
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377444
DO - https://doi.org/10.1039/c6cp04280e
SN - 1463-9076
SN - 1463-9084
VL - 18
IS - 33
SP - 23320
EP - 23325
AN - OPUS4-37744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - RPRT
A1 - Thünemann, Andreas
A1 - Emmerling, Franziska
A1 - Hodoroaba, Vasile-Dan
T1 - Review of existing calibration or reference
N2 - We report on calibration standards of nanoparticles meeting the definition of a nanomaterial given by the European Commission (EU 2011) which are relevant for the characterisation methods applied in the NanoDefine project. We found that the Impact of nanoparticles is outstanding in the scientific literature. A number of 270.000 paper titles on nanoparticles are listed in the Web of Science data base. But surprisingly, the availability of suitable certified standard reference materials is scarce. Only a few sources were found. For example, BAM provides the database Nanoscaled Reference Materials at http://www.nano-refmat.bam.de/en/ in cooperation with the ISO/TC 229 Nanotechnologies. In addition, two publications from 2013 on nanoscale reference materials are available. Candidates of nano-(certified) reference materials from other ongoing or just finished FP6 and FP7 nano-metrology projects have been extracted from the Compendium of Projects in the European NanoSafety Cluster (Compendium NSC, 2013). Recommendations for selection of representative test materials and calibration standards for NanoDefine internal tasks, respectively, are also given.
KW - Nanomaterial
KW - Reference materials
KW - Certified reference materials
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389836
UR - http://www.nanodefine.eu/index.php/downloads/nanodefine-technical-reports
SP - 1
EP - 18
CY - Wageningen, The Netherlands
AN - OPUS4-38983
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haferkamp, Sebastian
A1 - Fischer, Franziska
A1 - Kraus, Werner
A1 - Emmerling, Franziska
T1 - Mechanochemical Knoevenagel condensation investigated in situ
N2 - The mechanochemical Knoevenagel condensation of malononitrile with p-nitrobenzaldehyde was studied in situ using a tandem approach. X-ray diffraction and Raman spectroscopy were combined to yield time-resolved information on the milling process. Under solvent-free conditions, the reaction leads to a quantitative conversion to p-nitrobenzylidenemalononitrile within 50 minutes. The in situ data indicate that the process is fast and proceeds under a direct conversion. After stopping the milling process, the reaction continues until complete conversion. The continuous and the stopped milling process both result in crystalline products suitable for single crystal X-ray diffraction.
KW - Mechanochemistry
KW - Ball milling
KW - C–C coupling
KW - In situ
KW - Knoevenagel condensation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425388
DO - https://doi.org/10.3762/bjoc.13.197
VL - 13
SP - 2010
EP - 2014
PB - Beilstein-Institut
AN - OPUS4-42538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haugen, Øyvind P.
A1 - Polanco-Garriz, Itziar
A1 - Alcolea-Rodriguez, Victor
A1 - Portela, Raquel
A1 - Bæra, Rita
A1 - Sadeghiankaffash, Hamed
A1 - Hildebrandt, Jana
A1 - Ciornii, Dmitri
A1 - Altmann, Korinna
A1 - Barbero, Francesco
A1 - Fenoglio, Ivana
A1 - Reinosa, Julián J.
A1 - Fernández, José F.
A1 - Katsumiti, Alberto
A1 - Camassa, Laura M.A.
A1 - Wallin, Håkan
A1 - Zienolddiny-Narui, Shan
A1 - Afanou, Anani K.
T1 - Activation of Toll-like receptor 2 reveals microbial contamination beyond endotoxins on micro- and nanoplastics
N2 - Current literature on health hazards associated with micro- and nanoplastics (MNPs) is largely influenced by studies that insufficiently account for potential microbial contamination of their test materials. This may lead to misinterpretation of outcomes, as the test materials may be incorrectly considered pristine MNPs. The present study screened eight MNP test materials for microbial contaminants using Toll-like receptor (TLR) reporter cells for TLR2 and TLR4 and the commonly used Limulus amebocyte lysate (LAL) assay. Our results show that MNPs testing negative for endotoxins, based on the absence of TLR4 activation and negative LAL results, may still contain microbial ligands that selectively activate TLR2. Moreover, five of the eight MNP test materials contained microbial ligands capable of activating TLR2 and/or TLR4. Compared to the LAL assay, TLR4-based screening effectively detected endotoxin contamination. Overall, we found that the TLR reporter cell assay provides broader coverage than the LAL assay in detecting microbial ligands, which appear to be highly prevalent in MNP test materials.
KW - Nanoplastics
KW - Microplastics
KW - Microbial contamination
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653286
DO - https://doi.org/10.1016/j.tiv.2025.106190
SN - 0887-2333
VL - 112
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-65328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Putzu, Mara
A1 - Wiesner, Yosri
A1 - Weimann, Christiane
A1 - Hodoroaba, Vasile-Dan
A1 - Muniategui Lorenzo, Soledad
A1 - Fernández-Gonzáles, Verónica
A1 - Booth, Andy M.
A1 - Igartua, Amaia
A1 - Benismail, Nizar
A1 - Coïc, Laureen
A1 - Chivas-Joly, Carine
A1 - Fenoglio, Ivana
A1 - Rossi, Andrea Mario
A1 - Giovannozzi, Andrea Mario
A1 - Altmann, Korinna
T1 - Optimization of tablet processing as a reference material for microplastic detection methods
N2 - Reference materials (RMs) are essential and highly demanded tools for the development and validation of methods for microplastic (MP) quantification in complex matrices, to ensure comparable and harmonized approaches aligned with EU commission criteria for monitoring MPs (e.g., Drinking Water Directive and Urban Wastewater Treatment Directive). This study investigates different approaches for optimizing the production of polypropylene (PP) RMs in the form of water-soluble tablets, which were carefully evaluated for their homogeneity and stability according to ISO Guide 30, ISO 33401, and ISO 33405. PP particles (1–100 μm) were produced by cryomilling and embedded in a lactose/PEG matrix, then pressed into tablets (18 µg theoretical PP mass). The production process was optimized by varying (i) the size distribution of the matrix components and (ii) the mixer instrument. The materials obtained were characterized by thermogravimetric analysis to assess the homogeneity distribution of MPs with respect to PP mass in the individual tablets and their stability over a 4-month period. The most promising approach, with a homogenous mass of 19 μg (standard deviation of 4 μg), relative standard deviation of 19%, was further investigated for homogeneity by comparison with thermo-analytical mass determination methods, such as TED-GC/MS (thermal extraction desorption-gas chromatography/mass spectrometry) and Py-GC/MS (pyrolysis-gas chromatography-mass spectrometry), and for number-based characterization using micro-Raman spectroscopy. Material characterization was also examined using laser diffraction, scanning electron microscopy, and ATR-FTIR. Based on the results, the optimized processing protocol yields a PP RM suitable for quality control and method performance studies supporting standardization.
KW - Microplastics
KW - TED-GC/MS
KW - Reference materials
KW - Polypropylene
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653290
DO - https://doi.org/10.1007/s00216-025-06271-7
SN - 1618-2642
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65329
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiesner, Yosri
A1 - Eisentraut, Paul
A1 - Altmann, Korinna
T1 - One Year Observation of Microplastic Concentrations in the River Rhine
N2 - In recent years, the quantification of microplastics (MP) in aquatic environments has gained increasing attention, particularly regarding their environmental distribution and potential exposure levels. Environmentally relevant exposure data are still essential for a realistic risk assessment of the harmful health potential of microplastics in freshwater systems. This study addresses a large data set of MP concentrations analyzed and processed under statistical aspects and provides mass concentrations as well as associated size fractions of the detected MP. Over a 12 month period, samples were collected at three locations and analyzed across three particle size fractions (100−500 μm, 50−100 μm, and 10−50 μm) using thermalextraction desorption-gas chromatography/mass spectrometry (TED-GC/MS). The most prevalent polymers identified were polyethylene (PE), polypropylene (PP), polystyrene (PS), styrene−butadiene rubber (SBR), and natural rubber (NR). Statistical analyses, including principal component and cluster analysis, revealed size-dependent patterns,minor seasonal variation and spatial variations. These findings are particularly significant for ecotoxicological research and regulatory development, especially regarding tire abrasion a rarely quantified but potentially harmful MP source. The study contributes aluable data for future environmental monitoring and supports EU directives on wastewater and drinking water quality
KW - TED-GC/MS
KW - Microplastics
KW - Environment
KW - Monitoring
KW - Reference data
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654669
DO - https://doi.org/10.1021/acsestwater.5c00530
SN - 2690-0637
SP - 1
EP - 10
PB - American Chemical Society (ACS)
AN - OPUS4-65466
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hemingway, Jack M.
A1 - Quayle, Heather M.
A1 - Byrne, Cian
A1 - Pulham, Colin R.
A1 - Mondal, Subrata
A1 - Michalchuk, Adam
A1 - Morrison, Carole A.
T1 - Predicting impact sensitivities for an extended set of energetic materials via the vibrational up-pumping model: Molecular-based structure–property relationships identified
N2 - We have applied the vibrational up-pumping model to predict the mechanically-induced impact sensitivities of 33 molecular energetic crystals. Overall, the current model successfully identifies and ranks the compounds that are most sensitive to mechanical initiation, but offers poorer differentiation between compounds with lower sensitivity. Further developments to include the effects of trigger bond activation led to significant improvements in predictive capability. We show that this structure–property model highlights the importance of molecular flexibility in predicting impact sensitivity, and furthermore, we show that the Kier molecular flexibility index, which can be obtained from a SMILES string, offers a simple molecular-based descriptor that goes some way towards predicting the sensitivity of energetic materials.
KW - Vibrational
KW - Pyrazoles
KW - Comprising
KW - Electronic
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632651
DO - https://doi.org/10.1039/d5cp00852b
SN - 1463-9076
VL - 27
IS - 22
SP - 11640
EP - 11648
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-63265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghiringhelli, Luca M.
A1 - Baldauf, Carsten
A1 - Bereau, Tristan
A1 - Brockhauser, Sandor
A1 - Carbogno, Christian
A1 - Chamanara, Javad
A1 - Cozzini, Stefano
A1 - Curtarolo, Stefano
A1 - Draxl, Claudia
A1 - Dwaraknath, Shyam
A1 - Fekete, Ádám
A1 - Kermode, James
A1 - Koch, Christoph T.
A1 - Kühbach, Markus
A1 - Ladines, Alvin Noe
A1 - Lambrix, Patrick
A1 - Himmer, Maja-Olivia
A1 - Levchenko, Sergey V.
A1 - Oliveira, Micael
A1 - Michalchuk, Adam
A1 - Miller, Ronald E.
A1 - Onat, Berk
A1 - Pavone, Pasquale
A1 - Pizzi, Giovanni
A1 - Regler, Benjamin
A1 - Rignanese, Gian-Marco
A1 - Schaarschmidt, Jörg
A1 - Scheidgen, Markus
A1 - Schneidewind, Astrid
A1 - Sheveleva, Tatyana
A1 - Su, Chuanxun
A1 - Usvyat, Denis
A1 - Valsson, Omar
A1 - Wöll, Christof
A1 - Scheffler, Matthias
T1 - Shared metadata for data-centric materials science
N2 - The expansive production of data in materials science, their widespread sharing and repurposing requires educated support and stewardship. In order to ensure that this need helps rather than hinders scientific work, the implementation of the FAIR-data principles (Findable, Accessible, Interoperable, and Reusable) must not be too narrow. Besides, the wider materials-science community ought to agree on the strategies to tackle the challenges that are specific to its data, both from computations and experiments. In this paper, we present the result of the discussions held at the workshop on “Shared Metadata and Data Formats for Big-Data Driven Materials Science”. We start from an operative definition of metadata, and the features that a FAIR-compliant metadata schema should have. We will mainly focus on computational materials-science data and propose a constructive approach for the FAIRification of the (meta)data related to ground-state and excited-states calculations, potential-energy sampling, and generalized workflows. Finally, challenges with the FAIRification of experimental (meta)data and materials-science ontologies are presented together with an outlook of how to meet them.
KW - Library and Information Sciences
KW - Statistics, Probability and Uncertainty
KW - Computer Science Applications
KW - Education
KW - Information Systems
KW - Statistics and Probability
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584846
DO - https://doi.org/10.1038/s41597-023-02501-8
VL - 10
IS - 1
SP - 1
EP - 18
PB - Springer Science and Business Media LLC
AN - OPUS4-58484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
T1 - On the physical processes of mechanochemically induced transformations in molecular solids
N2 - Initiating or sustaining physical and chemical transformations with mechanical force – mechanochemistry – provides an opportunity for more sustainable chemical processes, and access to new chemical reactivity.
KW - Molecular solids
KW - Transformation
KW - Destabilisation
KW - Instabilities
KW - Common phenomenon
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621755
DO - https://doi.org/10.1039/d4cc04062g
IS - 99
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62175
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Driscoll, Laura L.
A1 - Driscoll, Elizabeth H.
A1 - Dong, Bo
A1 - Sayed, Farheen N.
A1 - Wilson, Jacob N.
A1 - O’Keefe, Christopher A.
A1 - Gardner, Dominic J.
A1 - Grey, Clare P.
A1 - Allan, Phoebe K.
A1 - Michalchuk, Adam
A1 - Slater, Peter R.
T1 - Under pressure: offering fundamental insight into structural changes on ball milling battery materials
N2 - Synthesis of Li ion battery materials via ball milling has been a huge area of growth, leading to new high-capacity electrode materials, such as a number of promising disordered rocksalt (DRS) phases. In prior work, it was generally assumed that the synthesis was facilitated simply by local heating effects during the milling process. In this work, we show that ball milling Li2MoO4 leads to a phase transformation to the high pressure spinel polymorph and we report electrochemical data for this phase. This observation of the formation of a high pressure polymorph shows that local heating effects alone cannot explain the phase transformation observed (phenakite to spinel) and so indicates the importance of other effects. In particular, we propose that when the milling balls collide with the material, the resulting shockwaves exert a localised pressure effect, in addition to local heating. To provide further support for this, we additionally report ball milling results for a number of case studies (Li2MnO3, Li2SnO3, Nb2O5) which reinforces the conclusion that local heating alone cannot explain the phase transformations observed. The work presented thus provides greater fundamental understanding of milling as a synthetic pathway and suggests potential strategies to prepare such samples without milling (e.g., doping to create internal chemical pressure). In addition, we suggest that further research is needed into the effect of the use of milling as a route to smaller particles, since we believe that such milling may also be affecting the surface structure of the particles through the influence of the shockwaves generated.
KW - Pollution
KW - Nuclear Energy and Engineering
KW - Sustainability and the Environment
KW - Environmental Chemistry
KW - Renewable Energy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590086
DO - https://doi.org/10.1039/d3ee00249g
VL - 16
IS - 11
SP - 5196
EP - 5209
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wimmer, L
A1 - Hoang, M V N
A1 - Schwarzinger, J
A1 - Jovanovic, V
A1 - Adelkovic, B
A1 - Velickovic, T C
A1 - Meisel, T C
A1 - Waniek, T
A1 - Weimann, Christiane
A1 - Altmann, Korinna
A1 - Dailey, L A
T1 - A quality-by-design inspired approach to develop PET and PP nanoplastic test materials for use in in vitro and in vivo biological assays
N2 - Micro- and nanoplastics have become environmental pollutants of concern, receiving increased attention from consumers, scientists, and policymakers. The lack of knowledge about possible impacts on wildlife and human health requires further research, for which well-characterized testmaterials are needed. A quality-bydesign (QbD) driven approachwas used to produce sterile, endotoxinmonitored nanoplastics of polyethylene terephthalate (PET) and polypropylene (PP) with a size fraction of >90% below 1 μm and high yield of >90%. Glycerol was used as a versatile and biocompatible liquid storage medium which requires no further exogenous dispersing agent andmaintained colloidal stability, sterility (0 CFU mL−1), and low endotoxin levels (<0.1 EU mL−1) for more than one year of storage at room temperature. Further, the glycerol vehicle showed no biological effect on the tested human bronchial cell line Calu-3 up to 0.8% (w/v). Given the concentration of 40 mg g−1 nanoplastics in the glycerol stock, this corresponds to a nanoplastic concentration of 320 μg mL−1. The surfactant-free nanoplastics are dispersible in bio-relevant media from the glycerol stock without changing size characteristics and are suitable for in vitro and in vivo research.
KW - Microplastics
KW - Reference materials
KW - Nanoplastics
KW - Polymer 3R
KW - Glycerol
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629934
DO - https://doi.org/10.1039/D4EN01186D
SN - 2051-8161
VL - 12
IS - 5
SP - 2667
EP - 2686
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-62993
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Prinz, Carsten
A1 - Prieto-Laria, P.
A1 - Ruiz-Salvador, A.R.
A1 - Ballesteros, M.
T1 - Engineering a multivariate cobalt metal–organic framework for high photocatalytic activity: the impact of mixed ligands and metal incorporation in a visible light-driven heterogeneous photo-Fenton reaction for water treatment
N2 - Metal–organic frameworks (MOFs) have attracted increasing attention for the removal of organic pollutants in wastewater via photocatalysis. Here, we design a multivariate modification of ZIF-9 to tune its electronic properties for use in visible light photocatalysis. A controllable synthesis of ZIF-9 and its multivariate forms with the incorporation of copper and the 2-imidazolecarboxaldehyde (ica) ligand was carried out. The materials are tested for the removal of the model dye methylene blue (MB) by a heterogeneous photo-Fenton-like reaction at neutral pH and room temperature. Cu-ZIF-9-ica (UPO-3) shows high photocatalytic activity under both visible and ultraviolet A (UVA) light, achieving 94% MB degradation in 45 min, compared to 65% MB degradation in 120 min using bare ZIF-9. The study revealed a first-order rate constant of 0.0475 min−1 for Cu-ZIF-9-ica compared to 0.0088 min−1 for ZIF-9 under visible light. The improvement of the catalyst was clearly attributed to the co-incorporation of Cu and the ica ligand in the MOF, which reduces the band gap, in agreement with DFT calculations. Reproducibility and recyclability tests proved that Cu-ZIF-9-ica can be used for at least 3 cycles without a significant loss of efficiency, making it a promising material for the study and application of wastewater treatment.
KW - Metal-Organic Framework (MOF)
KW - Heterogeneous photo-Fenton
KW - ZIF-9
KW - Methylene Blue
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630797
DO - https://doi.org/10.1039/d4na00954a
SN - 2516-0230
VL - 7
IS - 8
SP - 2255
EP - 2265
PB - Royal Society of Chemistry
AN - OPUS4-63079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Visileanu, Emilia
A1 - Catalin Grosu, Marian
A1 - Tiberiu Miclea, Paul
A1 - Altmann, Korinna
A1 - Brossell, Dirk
T1 - Methods for the collection and characterization of airborne particles in the textile industry
N2 - Airborne particulate matter is one of the main air pollutants. Their impact on mortality, and the occurrence of pulmonary and cardiovascular complications, have been the subject of numerous studies. Airborne particles are complex mixtures of organic and inorganic substances from different sources of particle emissions. Particulate Matter (PM) particles are classified according to their aerodynamic diameter expressed in µm and can vary from coarse (PM 10) to fine (less than PM 2.5). These diameter considerations are fundamental because they condition the penetration of particles into the bronchopulmonary system and the body. In recent years, there has been an interest in so-called “ultra-fine” particles, with a diameter of 0.1 µm (or 100 nm), or PM 0.1. They are nanoparticles and their impact on human health is not yet clear.With more than 1.5 million employees, textiles and clothing is a diverse sector that plays an important role in the European manufacturing industry, producing a turnover of €162 billion.An important component of the solid particles that generate air pollution in the textile industry is microplastics (MP) and nano plastics (NP), which also include microfibers (<5mm) and nanofibers (<100 nm), respectively. The particles released into the air during fiber and yarn processing range from 1 µg/m3 to 50 µg/m3.The paper presents the results of the determination of indoor and outdoor air concentration levels in textile companies, to identify the areas with the highest concentration level, by using an online recording system such as the Laser Aerosol Spectrometer MINI LAS model 11-E. The total concentration level TSP (µg/m3), the fractions PM 10(µg/m3), PM 2.5(µg/m3), PM1(µg/m3), as well as the total number of particles TC (1/l), were shown. It was noted that TSP is approximately at the same level both indoors and outdoors, but the fractions of PM10, PM2.5, and PM1 have much higher values indoors than outdoors with possible consequences on workers' health.The next step was the collection of fibers, namely micro and nano plastic particles from the vicinity of the workplaces of polyester, polyamide, and polypropylene fibers processing units in the textile industry in Romania, to obtain a sufficient quantity for laboratory analysis to determine the size and shape of the particles as well as their chemical composition. Two types of pumps were used, differentiated by their operating parameters: TECORA SKYPOST with airflow of 38 l/min and GILAIRPLUS with airflow 2l/min. Filters made of different materials with different diameters and pore sizes were used, namely: quartz filters (ø 47 mm, and ø 37 mm) on a TECORA SKYPOST type pump, polycarbonate nucleopore coated with a gold membrane (ø 25 mm) and silica filter (ø 9 mm) on GILAIRPLUS type pump.Using descriptive statistics, the calculation of correlation coefficients highlighted a strong correlation between the variables: "Collected mass/ Air concentration" and "Collected mass/ Air volume" for all diameters of the filters.The highest collected particle volume, determined by weighing the filters before and after collection, was obtained with the quartz filters (ø 47 mm) at an airflow of 38 l/min. The particles collected (polyester, polyamide, polypropylene) in the first stage were analyzed by SEM and thermogravimetric and it was found that the quartz filters absorbed the particles inside, with very few remaining on the surface. Thus no known methods can be used to perform analysis for particles collected on quartz filters. The number of particles on the filters was insufficient for analysis either because of the collection parameters used or because of the loss of particles during transport. As a result, in the next step, the use of 9 mm Si filters using the GILAIRPLUS pump at an airflow rate of 2l/min was chosen.To improve the transport conditions and avoid the loss of the particles and keep them on the surface of the filters, two methods were applied:- after weighing the filters were reintroduced into the collection pump holder;- a filtration system for airborne micro-nano plastics was designed and manufactured to selectively collect and transport PM10 and PM1 particles collected on SI filters.In both cases, SEM, Raman mapping, and GS-MS microscopy were used for analysis.Several times more PM10 than PM1 (74.5µg compared to 12.5 µg) was found. In all cases, both particles and fibers showed the same Raman fingerprint.The GS-MS analyses showed some contamination of the workspaces with particles other than the processed fibers. The presence of non-notifiable substances was also observed.The most viable filters are Si filters with a pore size of 10 microns to 1 micron and the use of the selected collection and transport filter system. In the following a filter system will be applied for collection on Au membrane-coated polycarbonate filters.
T2 - 5th International Conference on Human Systems Engineering and Design: Future Trends and Applications (IHSED 2023)
KW - Microplastics
KW - Textiles
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624442
DO - https://doi.org/10.54941/ahfe1004132
VL - 112
SP - 212
EP - 223
PB - AHFE International
AN - OPUS4-62444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Emmerling, Franziska
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Exploring new materials for Green Intelligent Building - How can our BAMline help?
N2 - In the scope of exploring and characterizing new materials related to Green Intelligent Building (GIB), we will provide an overview of the X-ray spectroscopy and diffraction analytical methods available at the BAMline /1/. and Myspot beamlines. These are two universal beamlines at the Berlin Synchrotron BESSY-II, where BAM has access and supervision role. Overarching electronic and structural properties at different time and length scales, such measurements enable a real-time characterization of materials properties. We will show-case in situ and ex situ deterioration and hydration studies on cement-based constructure materials.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - BAMline
KW - Scope of exploring
KW - Green intelligent building
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612882
SN - 978-3-9818564-7-7
SP - 30
EP - 36
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kader, A.
A1 - Snellings, J.
A1 - Adams, L. C.
A1 - Gottheil, P.
A1 - Mangarova, D. B.
A1 - Heyl, J. L.
A1 - Kaufmann, Jan Ole
A1 - Moeckel, J.
A1 - Brangsch, J.
A1 - Auer, T. A.
A1 - Collettini, F.
A1 - Sauer, F.
A1 - Hamm, B.
A1 - Käs, J.
A1 - Sack, I.
A1 - Makowski, M. R.
A1 - Braun, J.
T1 - Sensitivity of magnetic resonance elastography to extracellular matrix and cell motility in human prostate cancer cell line-derived xenograft models
N2 - Prostate cancer (PCa) is a significant health problem in the male population of the Western world. Magnetic resonance elastography (MRE), an emerging medical imaging technique sensitive to mechanical properties of biological tissues, detects PCa based on abnormally high stiffness and viscosity values. Yet, the origin of these changes in tissue properties and how they correlate with histopathological markers and tumor aggressiveness are largely unknown, hindering the use of tumor biomechanical properties for establishing a noninvasive PCa staging system.
To infer the contributions of extracellular matrix (ECM) components and cell motility, we investigated fresh tissue specimens from two PCa xenograft mouse models, PC3 and LNCaP, using magnetic resonance elastography (MRE), diffusion-weighted imaging (DWI), quantitative histology, and nuclear shape analysis. Increased tumor stiffness and impaired water diffusion were observed to be associated with collagen and elastin accumulation and decreased cell motility. Overall, LNCaP, while more representative of clinical PCa than PC3, accumulated fewer ECM components, induced less restriction of water diffusion, and exhibited increased cell motility, resulting in overall softer and less viscous properties. Taken together, our results suggest that prostate tumor stiffness increases with ECM accumulation and cell adhesion - characteristics that influence critical biological processes of cancer development.
MRE paired with DWI provides a powerful set of imaging markers that can potentially predict prostate tumor development from benign masses to aggressive malignancies in patients. Statement of significance: Xenograft models of human prostate tumor cell lines, allowing correlation of microstructure-sensitive biophysical imaging parameters with quantitative histological methods, can be investigated to identify hallmarks of cancer.
KW - Magnetic resonance elastography
KW - Quantitative histology
KW - Prostate cancer
KW - Stiffness
KW - Fluidity
KW - Apparent diffusion coefficient
KW - Collagen
KW - Elastin
KW - Nuclear shape
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618361
DO - https://doi.org/10.1016/j.bioadv.2024.213884
SN - 2772-9508
VL - 161
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mangarova, Dilyana Branimirova
A1 - Reimann, Carolin
A1 - Kaufmann, Jan Ole
A1 - Möckel, Jana
A1 - Kader, Avan
A1 - Adams, Lisa Christine
A1 - Ludwig, Antje
A1 - Onthank, David
A1 - Robinson, Simon
A1 - Karst, Uwe
A1 - Helmer, Rebecca
A1 - Botnar, Rene
A1 - Hamm, Bernd
A1 - Makowski, Marcus Richard
A1 - Brangsch, Julia
T1 - Elastin-specific MR probe for visualization and evaluation of an interleukin-1β targeted therapy for atherosclerosis
N2 - Atherosclerosis is a chronic inflammatory condition of the arteries and represents the primary cause of various cardiovascular diseases. Despite ongoing progress, finding effective anti-inflammatory therapeutic strategies for atherosclerosis remains a challenge. Here, we assessed the potential of molecular magnetic resonance imaging (MRI) to visualize the effects of 01BSUR, an anti-interleukin-1β monoclonal antibody, for treating atherosclerosis in a murine model. Male apolipoprotein E-deficient mice were divided into a therapy group (01BSUR, 2 × 0.3 mg/kg subcutaneously, n = 10) and control group (no treatment, n = 10) and received a high-fat diet for eight weeks. The plaque burden was assessed using an elastin-targeted gadolinium-based contrast probe (0.2 mmol/kg intravenously) on a 3 T MRI scanner. T1-weighted imaging showed a significantly lower contrast-to-noise (CNR) ratio in the 01BSUR group (pre: 3.93042664; post: 8.4007067) compared to the control group (pre: 3.70679168; post: 13.2982156) following administration of the elastin-specific MRI probe (p < 0.05). Histological examinations demonstrated a significant reduction in plaque size (p < 0.05) and a significant decrease in plaque elastin content (p < 0.05) in the treatment group compared to control animals. This study demonstrated that 01BSUR hinders the progression of atherosclerosis in a mouse model. Using an elastin-targeted MRI probe, we could quantify these therapeutic effects in MRI.
N2 - Atherosklerose ist eine chronische entzündliche Erkrankung der Arterien und die Hauptursache für verschiedene Herz-Kreislauf-Erkrankungen. Trotz kontinuierlicher Fortschritte ist es nach wie vor schwierig, wirksame entzündungshemmende Therapiestrategien für Atherosklerose zu finden. In dieser Studie haben wir das Potenzial der molekularen Magnetresonanztomographie (MRT) zur Visualisierung der Wirkung von 01BSUR, einem monoklonalen Anti-Interleukin-1β-Antikörper, zur Behandlung von Atherosklerose in einem Mausmodell untersucht. Männliche Apolipoprotein-E-defiziente Mäuse wurden in eine Therapiegruppe (01BSUR, 2 × 0,3 mg/kg subkutan, n = 10) und eine Kontrollgruppe (keine Behandlung, n = 10) aufgeteilt und erhielten acht Wochen lang eine fettreiche Diät. Die Plaquebelastung wurde mit einer auf Elastin ausgerichteten Kontrastmittelsonde auf Gadoliniumbasis (0,2 mmol/kg intravenös) auf einem 3-T-MRT-Scanner untersucht. Die T1-gewichtete Bildgebung zeigte ein signifikant niedrigeres Kontrast-Rausch-Verhältnis (CNR) in der 01BSUR-Gruppe (vorher: 3,93042664; nachher: 8,4007067) im Vergleich zur Kontrollgruppe (vorher: 3,70679168; nachher: 13,2982156) nach Verabreichung der Elastin-spezifischen MRT-Sonde (p < 0,05). Histologische Untersuchungen zeigten eine signifikante Verringerung der Plaque-Größe (p < 0,05) und eine signifikante Abnahme des Plaque-Elastin-Gehalts (p < 0,05) in der Behandlungsgruppe im Vergleich zu den Kontrolltieren. Diese Studie zeigte, dass 01BSUR das Fortschreiten der Atherosklerose in einem Mausmodell hemmt. Mit einer auf Elastin ausgerichteten MRT-Sonde konnten wir diese therapeutischen Effekte in der MRT quantifizieren.
KW - Atherosclerosis
KW - Molecular imaging
KW - Elastin
KW - Plaque
KW - Interleukin-1beta
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610858
DO - https://doi.org/10.1038/s41598-024-71716-5
VL - 14
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-61085
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nerger, Tino
A1 - Neumann, Patrick P.
A1 - Weller, Michael G.
T1 - Drone-Based Localization of Hazardous Chemicals by Passive Smart Dust
N2 - The distribution of tiny sensors over a specific area was first proposed in the late 1990s as a concept known as smart dust. Several efforts focused primarily on computing and networking capabilities, but quickly ran into problems related to power supply, cost, data transmission, and environmental pollution. To overcome these limitations, we propose using paper-based (confetti-like) chemosensors that exploit the inherent selectivity of chemical reagents, such as colorimetric indicators. In this work, cheap and biodegradable passive sensors made from cellulose could successfully indicate the presence of hazardous chemicals, e.g., strong acids, by a significant color change. A conventional color digital camera attached to a drone could easily detect this from a safe distance. The collected data were processed to define the hazardous area. Our work presents a combination of the smart dust concept, chemosensing, paper-based sensor technology, and low-cost drones for flexible, sensitive, economical, and rapid detection of hazardous chemicals in high-risk scenarios.
KW - Cellulose
KW - Passive Smart Dust
KW - Drohne
KW - Kolorimetrische Sensoren
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614641
DO - https://doi.org/10.3390/s24196195
VL - 24
IS - 19
SP - 1
EP - 16
PB - MDPI
AN - OPUS4-61464
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tscheuschner, Georg
A1 - Ponader, Marco
A1 - Raab, Christopher
A1 - Weider, Prisca S.
A1 - Hartfiel, Reni
A1 - Kaufmann, Jan Ole
A1 - Völzke, Jule L.
A1 - Bosc-Bierne, Gaby
A1 - Prinz, Carsten
A1 - Schwaar, T.
A1 - Andrle, Paul
A1 - Bäßler, Henriette
A1 - Nguyen, Khoa
A1 - Zhu, Y.
A1 - Mey, A. S. J. S.
A1 - Mostafa, A.
A1 - Bald, I.
A1 - Weller, Michael G.
T1 - Efficient Purification of Cowpea Chlorotic Mottle Virus by a Novel Peptide Aptamer
N2 - The cowpea chlorotic mottle virus (CCMV) is a plant virus explored as a nanotechnological platform. The robust self-assembly mechanism of its capsid protein allows for drug encapsulation and targeted delivery. Additionally, the capsid nanoparticle can be used as a programmable platform to display different molecular moieties. In view of future applications, efficient production and purification of plant viruses are key steps. In established protocols, the need for ultracentrifugation is a significant limitation due to cost, difficult scalability, and safety issues. In addition, the purity of the final virus isolate often remains unclear. Here, an advanced protocol for the purification of the CCMV from infected plant tissue was developed, focusing on efficiency, economy, and final purity. The protocol involves precipitation with PEG 8000, followed by affinity extraction using a novel peptide aptamer. The efficiency of the protocol was validated using size exclusion chromatography, MALDI-TOF mass spectrometry, reversed-phase HPLC, and sandwich immunoassay. Furthermore, it was demonstrated that the final eluate of the affinity column is of exceptional purity (98.4%) determined by HPLC and detection at 220 nm. The scale-up of our proposed method seems to be straightforward, which opens the way to the large-scale production of such nanomaterials. This highly improved protocol may facilitate the use and implementation of plant viruses as nanotechnological platforms for in vitro and in vivo applications.
N2 - Das Cowpea Chlorotic Mottle Virus (CCMV) ist ein Pflanzenvirus, das als nanotechnologische Plattform erforscht wird. Der robuste Selbstorganisationsmechanismus seines Kapsidproteins ermöglicht die Verkapselung und gezielte Abgabe von Medikamenten. Darüber hinaus kann das Kapsid-Nanopartikel als programmierbare Plattform für die Präsentation verschiedener molekularer Komponenten verwendet werden. Im Hinblick auf künftige Anwendungen ist eine effiziente Produktion und Reinigung von Pflanzenviren von entscheidender Bedeutung. In etablierten Protokollen stellt die notwendige Ultrazentrifugation aufgrund von Kosten, schwieriger Skalierbarkeit und Sicherheitsaspekten eine erhebliche Einschränkung dar. Darüber hinaus bleibt die Reinheit des endgültigen Virusisolats oft unklar. Hier wurde ein fortschrittliches Protokoll für die Reinigung von CCMV aus infiziertem Pflanzengewebe entwickelt, wobei der Schwerpunkt auf Effizienz, Wirtschaftlichkeit und Reinheit lag. Das Protokoll beinhaltet eine Fällung mit Polyethylenglycol (PEG 8000), gefolgt von einer Affinitätsextraktion mit einem neuartigen Peptid-Aptamer. Die Effizienz des Protokolls wurde mithilfe von Größenausschluss-Chromatographie (SEC), MALDI-TOF-Massenspektrometrie, Umkehrphasen-HPLC und Sandwich-Immunoassay validiert. Darüber hinaus wurde nachgewiesen, dass das endgültige Eluat der Affinitätssäule eine außergewöhnliche Reinheit (98,4 %) aufweist, die durch HPLC und Detektion bei 220 nm bestimmt wurde. Die Skalierung der von uns vorgeschlagenen Methode scheint einfach zu sein, was den Weg für eine größer angelegte Produktion solcher Nanomaterialien ebnet. Dieses stark verbesserte Protokoll könnte die Verwendung und Umsetzung von Pflanzenviren als nanotechnologische Plattformen für In-vitro- und In-vivo-Anwendungen erleichtern.
KW - Affinity chromatography
KW - Nanoparticles
KW - Nanoscience
KW - Carrier protein
KW - Encapsulation
KW - Combinatorial peptide library
KW - Peptide binder
KW - Vigna unguiculata
KW - Augenbohne
KW - Schlangenbohne
KW - Pflanzenvirus
KW - Plant virus
KW - Upscaling
KW - Commercialization
KW - Reference material
KW - Nanocarrier
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572645
DO - https://doi.org/10.3390/v15030697
VL - 15
IS - 3
SP - 1
EP - 24
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-57264
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beslic, D.
A1 - Tscheuschner, Georg
A1 - Renard, B. Y.
A1 - Weller, Michael G.
A1 - Muth, Thilo
T1 - Comprehensive evaluation of peptide de novo sequencing tools for monoclonal antibody assembly
N2 - Monoclonal antibodies are biotechnologically produced proteins with various applications in research, therapeutics and diagnostics. Their ability to recognize and bind to specific molecule structures makes them essential research tools and therapeutic agents. Sequence information of antibodies is helpful for understanding antibody–antigen interactions and ensuring their affinity and specificity. De novo protein sequencing based on mass spectrometry is a valuable method to obtain the amino acid sequence of peptides and proteins without a priori knowledge. In this study, we evaluated six recently developed de novo peptide sequencing algorithms (Novor, pNovo 3, DeepNovo, SMSNet, PointNovo and Casanovo), which were not specifically designed for antibody data. We validated their ability to identify and assemble antibody sequences on three multi-enzymatic data sets. The deep learning-based tools Casanovo and PointNovo showed an increased peptide recall across different enzymes and data sets compared with spectrum-graph-based approaches. We evaluated different error types of de novo peptide sequencing tools and their performance for different numbers of missing cleavage sites, noisy spectra and peptides of various lengths. We achieved a sequence coverage of 97.69–99.53% on the light chains of three different antibody data sets using the de Bruijn assembler ALPS and the predictions from Casanovo. However, low sequence coverage and accuracy on the heavy chains demonstrate that complete de novo protein sequencing remains a challenging issue in proteomics that requires improved de novo error correction, alternative digestion strategies and hybrid approaches such as homology search to achieve high accuracy on long protein sequences.
KW - De novo peptide sequencing
KW - Bioinformatics
KW - Benchmarking study
KW - Monoclonal antibody
KW - Mass spectrometry
KW - Sequence coverage
KW - Light chains
KW - Heavy chains
KW - IgG
KW - Immunoglobulins
KW - Error correction
KW - Sequencing algorithm
KW - Preprocessing
KW - Missing fragmentation sites
KW - Deep learning-based tools
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570363
DO - https://doi.org/10.1093/bib/bbac542
VL - 24
IS - 1
SP - 1
EP - 12
PB - Oxford University Press
AN - OPUS4-57036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fröhlich-Nowoisky, J.
A1 - Bothen, N.
A1 - Backes, A. T.
A1 - Weller, Michael G.
A1 - Pöschl, U.
T1 - Oligomerization and tyrosine nitration enhance the allergenic potential of the birch and grass pollen allergens Bet v 1 and Phl p 5
N2 - Protein modifications such as oligomerization and tyrosine nitration alter the immune response to allergens and may contribute to the increasing prevalence of allergic diseases. In this mini-review, we summarize and discuss relevant findings for the major birch and grass pollen allergens Bet v 1 and Phl p 5 modified with tetranitromethane (laboratory studies), peroxynitrite (physiological processes), and ozone and nitrogen dioxide environmental conditions). We focus on tyrosine nitration and the formation of protein dimers and higher oligomers via dityrosine cross-linking and the immunological effects studied.
N2 - Proteinmodifikationen wie Oligomerisierung und Tyrosinnitrierung verändern die Immunantwort auf Allergene und tragen möglicherweise zur zunehmenden Prävalenz allergischer Erkrankungen bei. In diesem Mini-Review fassen wir relevante Befunde zu den wichtigsten Birken- und Gräserpollenallergenen Bet v 1 und Phl p 5 zusammen, die mit Tetranitromethan (Laborstudien), Peroxynitrit (physiologische Prozesse) und Ozon und Stickstoffdioxid (Umweltbedingungen). Wir konzentrieren uns auf die Tyrosin-Nitrierung und die Bildung von Proteindimeren und höheren Oligomeren durch Dityrosin-Vernetzung und deren immunologischen Auswirkungen.
KW - Allergy
KW - Nitration
KW - Protein oligomers
KW - Air pollution
KW - Ozone
KW - Nitrogen oxides
KW - Tyrosine
KW - Nitrotyrosine
KW - Dityrosine
KW - Dityrosine crosslinking
KW - Protein degradation
KW - Neoepitopes
KW - Neoallergen
KW - IgE
KW - Immunoglobulin E
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591453
DO - https://doi.org/10.3389/falgy.2023.1303943
VL - 4
SP - 1
EP - 8
PB - Frontiers Media
CY - Switzerland
AN - OPUS4-59145
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Reinmuth-Selzle, K.
A1 - Bellinghausen, I.
A1 - Leifke, A. L.
A1 - Backes, A. T.
A1 - Bothen, N.
A1 - Ziegler, K.
A1 - Weller, Michael G.
A1 - Saloga, J.
A1 - Schuppan, D.
A1 - Lucas, K.
A1 - Pöschl, U.
A1 - Fröhlich-Nowoisky, J.
T1 - Chemical modification by peroxynitrite enhances TLR4 activation of the grass pollen allergen Phl p 5
N2 - The chemical modification of aeroallergens by reactive oxygen and nitrogen species (ROS/RNS) may contribute to the growing prevalence of respiratory allergies in industrialized countries. Post-translational modifications can alter the immunological properties of proteins, but the underlying mechanisms and effects are not well understood. In this study, we investigate the Toll-like receptor 4 (TLR4) activation of the major birch and grass pollen allergens Bet v 1 and Phl p 5, and how the physiological oxidant peroxynitrite (ONOO–) changes the TLR4 activation through protein nitration and the formation of protein dimers and higher oligomers. Of the two allergens, Bet v 1 exhibited no TLR4 activation, but we found TLR4 activation of Phl p 5, which increased after modification with ONOO– and may play a role in the sensitization against this grass pollen allergen. We attribute the TLR4 activation mainly to the two-domain structure of Phl p 5 which may promote TLR4 dimerization and activation. The enhanced TLR4 signaling of the modified allergen indicates that the ONOO–-induced modifications affect relevant protein-receptor interactions. This may lead to increased sensitization to the grass pollen allergen and thus contribute to the increasing prevalence of allergies in the Anthropocene, the present era of globally pervasive anthropogenic influence on the environment.
KW - Bet v 1
KW - Birch pollen allergen
KW - Phl p 5
KW - Grass pollen
KW - Phleum pratense
KW - Betula pendula
KW - Nitration
KW - Nitrotyrosine
KW - Protein nitration
KW - Toll-like receptor 4
KW - Allergy
KW - Enhancement
KW - Oligomerization
KW - Dimerization
KW - TLR4 activation
KW - Air pollution
KW - Nitrogen oxides
KW - Inflammation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570298
DO - https://doi.org/10.3389/falgy.2023.1066392
VL - 4
SP - 1
EP - 7
PB - Frontiers Media SA
CY - Lausanne, Switzerland
AN - OPUS4-57029
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tchipilov, Teodor
A1 - Meyer, Klas
A1 - Weller, Michael G.
T1 - Quantitative 1H nuclear magnetic resonance (qNMR) of aromatic amino acids for protein quantification
N2 - Hydrolysis of protein samples into amino acids facilitates the use of NMR spectroscopy for protein and peptide quantification. Different conditions have been tested for quantifying aromatic amino acids and proteins. The pH-dependent signal shifts in the aromatic region of amino acid samples were examined. A pH of 12 was found to minimize signal overlap of the four aromatic amino acids. Several aromatic compounds, such as terephthalic acid, sulfoisophthalic acid, and benzene tricarboxylic acid, were applied as internal standards. The quantification of amino acids from an amino acid standard was performed. Using the first two suggested internal standards, recovery was ~97% for histidine, phenylalanine, and tyrosine at a concentration of approximately 1 mM in solution. Acidic hydrolysis of a certified reference material (CRM) of bovine serum albumin (BSA) and subsequent quantification of Phe and Tyr yielded recoveries of 98% ± 2% and 88% ± 4%, respectively, at a protein concentration of 16 g/L or 250 µM.
KW - Amino acid analysis
KW - Aromatic amino acid analysis
KW - AAA
KW - AAAA
KW - Protein hydrolysis
KW - Hydrochloric acid
KW - Metrology
KW - Traceability
KW - NIST
KW - Reference materials
KW - Internal standard
KW - Calibration
KW - Compound-independent calibration
KW - Histidine
KW - Tyrosine
KW - Tryptophan
KW - Phenylalanine
KW - Terephthalic acid
KW - Benzene-1,3,5-tricarboxylic acid
KW - Bovine serum albumin (BSA)
KW - Quantitative protein analysis
KW - Phenylketonuria
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570943
DO - https://doi.org/10.3390/mps6010011
VL - 6
IS - 1
SP - 1
EP - 13
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-57094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yanchen
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Montoro, Luciano A.
A1 - Liu, Hao
A1 - Liu, Ye
A1 - Emmerling, Franziska
A1 - Russo, Patrícia A.
A1 - Pinna, Nicola
T1 - A partially disordered crystallographic shear block structure as fast-charging negative electrode material for lithium-ion batteries
N2 - A well-ordered crystalline structure is crucial in battery electrodes, as the dimensionality and connectivity of the interstitial sites inherently influence Li+ ions diffusion kinetics. Niobium tungsten oxides block structures, composed of ReO3-type blocks of specific sizes with well-defined metal sites, are promising fast-charging negative electrode materials. Structural disorder is generally detrimental to conductivity or ion transport. However, here, we report an anomalous partially disordered Nb12WO33 structure that significantly enhances Li-ion storage performance compared to the known monoclinic Nb12WO33 phase. The partially disordered phase consists of corner-shared NbO6 octahedra blocks of varied sizes, including 5×4, 4×4, and 4×3, with a disordered arrangement of distorted WO4 tetrahedra at the corners of the blocks. This structural arrangement is robust during lithiation/delithiation, exhibiting minor local structure changes during cycling. It enables accelerated Li-ion migration, resulting in promising fast-charging performance, namely, 62.5 % and 44.7 % capacity retention at 20 C and 80 C, respectively. This study highlights the benefits of introducing disorder into niobium tungsten oxide shear structures, through the establishment of clear structure-performance correlations, offering guidelines for designing materials with targeted properties.
KW - Lithium ion batteries
KW - Oxides
KW - XANES
KW - XRD
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637994
DO - https://doi.org/10.1038/s41467-025-61646-9
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-63799
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Roy, Arkendu
A1 - Karafiludis, Stephanos
A1 - Kumar, Sourabh
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Stawski, Tomasz M.
A1 - Miliūtė, Aistė
A1 - von der Au, Marcus
A1 - Ahrens, Mike
A1 - Braun, Thomas
A1 - Emmerling, Franziska
T1 - Zirconium fluoride-supported high-entropy fluoride: a catalyst for enhanced oxygen evolution reaction
N2 - Extended hydrogen initiatives promote the urgency of research on water splitting technologies and, therein, oxygen evolution reaction catalysts being developed. A route to access a ZrF4 supported high-entropy fluoride catalyst using a facile sol–gel route is presented. The high-entropy character of the catalyst was confirmed by scanning transmission electron microscopy and energy dispersive X-ray spectroscopy (STEM-EDX) as well as inductively coupled plasma-mass spectrometry (ICP-MS). Additional investigations on the local structure were performed using extended X-ray absorption fine structure spectroscopy (EXAFS) and pair distribution function (PDF) analysis. The catalyst shows significant potential for oxygen evolution reaction (OER) in alkaline media with a current density of 100 mA cm−2 at approximately 1.60 V, thus outperforming benchmark materials such as IrO2, despite a significant reduction in electrochemical mass loading. A potential mechanism is suggested based on free energy calculation using DFT calculations.
KW - OER
KW - HEA
KW - CCMAT
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637116
DO - https://doi.org/10.1039/D4TA08664C
SN - 2050-7488
VL - 13
IS - 26
SP - 20383
EP - 20393
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmar, Stefan
A1 - Weyrauch, Steffen
A1 - Reemtsma, Thorsten
A1 - Eisentraut, Paul
A1 - Altmann, Korinna
A1 - Ruhl, Aki S.
A1 - Jekel, Martin
T1 - Settling Velocities of Tire and Road Wear Particles: Analyzing Finely Graded Density Fractions of Samples from a Road Simulator and a Highway Tunnel
N2 - The terminal settling velocity is considered the most critical parameter determining the transport of tire and road wear particles (TRWP) in aquatic environments. Nonetheless, no respective empirical data has been reported so far. In this study, particle samples from a road simulator and a highway tunnel were investigated with a validated imaging method. Different density and size fractions of both samples were measured separately, acquiring sizes and settling velocities of more than 30,000 individual particles. In addition, tire marker polymers were analyzed for each fraction via thermal extraction desorption-gas chromatography/mass spectrometry. Finally, the acquired particle data was combined according to the fractions’ estimated tire contents in order to deduce detailed probability distributions of particle size and settling velocity for the actual TRWP from both samples. Weighted by TRWP-incorporated tire mass, median diameters of 54 and 44 μm as well as median settling velocities of 0.65 and 0.22 mm/s were found for TRWP from the road simulator and highway tunnel, respectively. This study thus provides the first ever empirical data on TRWP settling velocities in water, which can be highly valuable input for modeling the environmental transport of TRWP and for dimensioning TRWP retention systems.
KW - Microplastics
KW - TED-GC/MS
KW - Sinking velocities
KW - Transport
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635449
DO - https://doi.org/10.1021/acs.est.5c04165
SN - 0013-936X
VL - 59
IS - 26
SP - 13434
EP - 13446
PB - American Chemical Society (ACS)
AN - OPUS4-63544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Prasenjit
A1 - Chakraborty, Gouri
A1 - Yang, Jin
A1 - Roeser, Jérôme
A1 - Küçükkeçeci, Hüseyin
A1 - Nguyen, Anh Dung
A1 - Schwarze, Michael
A1 - Gabriel, Jose
A1 - Penschke, Christopher
A1 - Du, Shengjun
A1 - Weigelt, Vincent
A1 - Khalil, Islam E.
A1 - Schmidt, Johannes
A1 - Saalfrank, Peter
A1 - Oschatz, Martin
A1 - Rabeah, Jabor
A1 - Schomäcker, Reinhard
A1 - Emmerling, Franziska
A1 - Thomas, Arne
T1 - The Effect of Pore Functionality in Multicomponent Covalent Organic Frameworks on Stable Long‐Term Photocatalytic H2 Production
N2 - AbstractIn nature, organic molecules play a vital role in light harvesting and photosynthesis. However, regarding artificial water splitting, the research focus is primarily on inorganic semiconductors. Although organic photocatalysts have high structural variability, they tend to exhibit lower quantum efficiencies for water splitting than their inorganic counterparts. Multicomponent reactions (MCRs) offer an attractive route to introduce different functional units into covalent organic frameworks (COFs) and enable semiconducting properties and high chemical stability, creating promising materials for long‐term photocatalytic applications, such as H2 production. Herein, five highly crystalline donor‐acceptor based, 4‐substituted quinoline‐linked MCR‐COFs are presented that are prepared via the three‐component Povarov reaction. The pore functionality is varied by applying different vinyl derivatives (e.g., styrene, 2‐vinyl pyridine, 4‐vinylpyridine, 4‐vinyl imidazole, 2,3,4,5,6‐pentafluorostyrene), which has a strong influence on the obtained photocatalytic activity. Especially an imidazole‐functionalized COF displays promising photocatalytic performance due to its high surface area, crystallinity, and wettability. These properties enable it to maintain its photocatalytic activity even in a membrane support. Furthermore, such MCR‐COFs display dramatically enhanced (photo)chemical stability even after long‐term solar light irradiation and exhibit a high and steady H2 evolution for at least 15 days.
KW - Sstability
KW - Covalent organic frameworks
KW - Pore functionality
KW - Long-term H2 production
KW - Multicomponent reactions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639787
DO - https://doi.org/10.1002/aenm.202501193
SN - 1614-6832
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-63978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Visileanu, Emilia
A1 - Altmann, Korinna
A1 - Stepa, Raluca
A1 - Haiducu, Maria
A1 - Miclea, Paul Tiberiu
A1 - Vladu, Alina
A1 - Dondea, Felicia
A1 - Grosu, Marian Catalin
A1 - Scarlat, Razvan
T1 - Comparative Analysis of Airborne Particle Concentrations in Textile Industry Environments Throughout the Workday
N2 - This paper addresses the growing concern surrounding microplastic pollution, particularly within the textile industry, and the associated potential health risks linked to the inhalation and ingestion of microplastic particles. Microplastics, defined as plastic particles smaller than five millimeters, are increasingly found not only in aquatic environments, but also in soils, air, and food. Although research on the health impacts of microplastics is still emerging, early studies indicate that these particles could contribute to health issues, including oxidative stress, inflammation, and cardiovascular diseases. Notably, individuals with higher concentrations of plastics in arterial plaques are more susceptible to heart attacks and strokes. In the textile industry, synthetic fibers such as polyester, nylon, and acrylic release microplastics into the air during production. The paper discusses a study conducted in a textile company that processes polyester yarns, where airborne microplastic concentrations were measured at various locations throughout the day. Particle sizes ranging from 0.3 nm to 10 nm were analyzed, revealing the presence of polyester polymers in the particulate matter. These findings underscore the widespread nature of microplastic pollution, particularly in industrial settings, and raise concerns about the health risks associated with prolonged exposure to airborne microplastics. While further research is necessary to fully understand the extent of these health impacts, preliminary data suggest a troubling link between microplastic inhalation and cardiovascular conditions.
KW - Microplastics
KW - Textiles
KW - Airborne particles
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635269
DO - https://doi.org/10.3390/microplastics4020034
SN - 2673-8929
VL - 4
IS - 2
SP - 1
EP - 17
PB - MDPI AG
AN - OPUS4-63526
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Domínguez-Santos, J. Enrique
A1 - Bhattacharya, Biswajit
A1 - Prinz, Carsten
A1 - Canosa, Inés
A1 - Flores, Amando
A1 - Jiménez-Rodríguez, Antonia
A1 - Ruiz-Salvador, A. Rabdel
A1 - Emmerling, Franziska
A1 - Ballesteros, Menta
T1 - Mechanochemical synthesis of multivariate UPO-3 (Cu-ZIF-9-ica) MOF for inactivation of antibiotic-resistant bacteria and irrigation-quality water production via heterogeneous photo-Fenton catalysis
N2 - Water scarcity and pollution are critical global challenges, particularly in agriculture, the largest consumer of water. The development of sustainable, effective, and environmentally friendly disinfection methods is essential to address the risks posed by antibiotic-resistant bacteria and to ensure safe reuse of water for irrigation. In this study, we report the synthesis of the metal-organic framework (MOF) Universidad Pablo de Olavide-3 (UPO-3) via a mechanochemical approach, a scalable and sustainable method compared to traditional solvothermal synthesis. The resulting UPO-3/H2O2 system exhibits robust photocatalytic properties under visible light, achieving effective and broad-spectrum antibacterial activity. The disinfection efficiency of the catalyst was evaluated against Escherichia coli as a model of microbial pathogen in two saline matrices, considering the key parameters of the heterogeneous photo-Fenton process, including catalyst dosage, initial H2O2 concentration, and light irradiation. Notably, it inactivated two important virulent and antibiotic-resistant bacterial pathogens (Staphylococcus aureus and Pseudomonas aeruginosa). Furthermore, UPO-3 shows exceptional performance under real-world conditions, such as river water disinfection, achieving >5-log reduction of E. coli, fulfilling a critical criterion for Class A water reuse under Regulation (EU) 2020/741. These results highlight UPO-3 as a versatile and sustainable solution for water reuse, addressing water scarcity and advancing efforts to achieve United Nations Sustainable Development Goal 6.
KW - Water reuse
KW - Antibiotic-resistant bacteria
KW - Water disinfection
KW - Mechanochemical synthesis
KW - Metal organic framework
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639766
DO - https://doi.org/10.1016/j.chemosphere.2025.144610
SN - 0045-6535
VL - 386
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63976
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Go, Eun Sul
A1 - Hong, Eun Ji
A1 - Lee, Ji Yeong
A1 - Stolar, Tomislav
A1 - Peterson, Gregory I.
A1 - Emmerling, Franziska
A1 - Kim, Kyoungsoo
A1 - Kim, Jeung Gon
T1 - Insights into Mechanochemical Solid-State Ball-Milling Reaction: Monitoring Transition from Heterogeneous to Homogeneous Conditions
N2 - As mechanochemical synthesis has advanced significantly, there has been intense interest in understanding the underlying mechanisms of these reactions. Given that many mechanochemical processes are conducted in the solid-state without solvation yet sometimes yield faster reactions than those in solution, we sought to address the following question: Are mechanochemical reactions homo- or heterogeneous? To investigate, we employed a model system involving the mixing and copolymerization of l-lactide (LLA) and d-lactide (DLA), monitored through powder X-ray diffraction (PXRD), nuclear magnetic resonance, and differential scanning calorimetry. In situ and ex situ PXRD analyses of the mixture of LLA and DLA showed that vibratory ball milling rapidly transformed the initially heterogeneous lactide mixture into a homogeneous phase within one min due to collisions between the balls and the jar. By varying the milling conditions, we were able to regulate the level of mixing, which subsequently influenced the copolymerization outcomes. In the solid-state ball-milling copolymerization of LLA and DLA in the presence of a catalyst and initiator, multiblock copolymers of poly(l-lactic acid) and poly(d-lactic acid) were formed within one min during the early stage of the reaction, when incomplete mixing of the monomers led to a process governed by phase heterogeneity. In contrast, prolonged polymerization promoted conditions approaching homogeneity, ultimately yielding atactic poly(lactic acid). This transition from heterogeneous to homogeneous reactions is a distinctive feature compared to conventional homogeneous reactions, potentially leading to mechano-exclusive reaction designs.
KW - Mechanochemistry
KW - Ball-milling
KW - Homogeneous reaction
KW - Heterogeneous reaction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638008
DO - https://doi.org/10.1021/jacsau.5c00322
SN - 2691-3704
VL - 5
IS - 6
SP - 2720
EP - 2727
PB - American Chemical Society (ACS)
AN - OPUS4-63800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Sustainable mechanochemical approach for the selective synthesis of multicomponent organic solids: real-time in situ insights
N2 - Crystalline multicomponent organic solids (MOSs) such as cocrystals and ionic cocrystals hold immense potential in diverse functional applications, ranging from pharmaceuticals to optoelectronics. However, conventional solution-based crystallization methods often result in polymorphic mixtures and lack precise control over product composition. Herein, we report a comparative investigation of solution crystallization versus mechanochemical synthesis for constructing MOSs from 9-anthracenecarboxylic acid (ACA) and 4,4 '-bipyridine (BPY). Solution-based approaches consistently yielded concomitant formation of neutral cocrystal (CC) and ionic cocrystal (ICC) forms, regardless of the solvent used. The resulting multicomponent solids were comprehensively characterized using a combination of single crystal X-ray diffraction, powder X-ray diffraction, Fourier-transform infrared spectroscopy, differential thermal analysis, and thermogravimetric analysis. In contrast, mechanochemical methods, including neat grinding (without solvent) and liquid-assisted grinding (with minimum solvent), enabled selective formation of either a phase pure CC or ICC form. Less polar and nonpolar organic solvents favor the kinetic CC, while polar water promotes formation of the thermodynamically stable ICC. Time-resolved in situ powder X-ray diffraction (TRIS-PXRD) captures the dynamic evolution of solid-state phases and reveals the complete transformation of the CC into ICC under neat grinding or water-assisted conditions. This study highlights the powerful role of mechanochemistry and in situ monitoring in steering solid-state reactivity and offers a sustainable pathway for the targeted and scalable synthesis of pure multicomponent organic materials.
KW - Cocrystal
KW - Synchrotron X-ray powder diffraction
KW - Time-resolved in situ investigation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641409
DO - https://doi.org/10.1039/D5CE00663E
SN - 1466-8033
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64140
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Scoppola, E.
A1 - Wolf, S.E.
A1 - Kochovski, Z.
A1 - Matzdorff, D.
A1 - Van Driessche, A. E. S.
A1 - Hövelmann, J.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz M.
T1 - Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formation
N2 - The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH₄PO₄ · 6H₂O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization. In this study, we use synchrotron-based in situ x-ray scattering complemented by cryogenic transmission electron microscopy to obtain new insights from the earliest stages of struvite formation. The holistic scattering data captured the structure of an entire assembly in a time-resolved manner. The structural features comprise the aqueous medium, the growing struvite crystals, and any potential heterogeneities or complex entities. By analysing the scattering data, we found that the onset of crystallization causes a perturbation in the structure of the surrounding aqueous medium. This perturbation is characterized by the occurrence and evolution of Ornstein-Zernike fluctuations on a scale of about 1 nm, suggesting a non-classical nature of the system. We interpret this phenomenon as a liquid-liquid phase separation, which gives rise to the formation of the amorphous precursor phase preceding actual crystal growth of struvite. Our microscopy results confirm that the formation of Mg-struvite includes a short-lived amorphous phase, lasting >10 s.
KW - Physical and theoretical chemistry
KW - Non-classical crystallization
KW - Struvite
KW - Liquid-liquid-phase-separation
KW - Nucleation
KW - Crystallization
KW - In-situ scattering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584766
DO - https://doi.org/10.1063/5.0166278
SN - 1089-7690
VL - 159
IS - 13
SP - 1
EP - 12
PB - AIP Publishing
CY - Woodbury, NY
AN - OPUS4-58476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Karafiludis, Stephanos
A1 - Pimentel, Carlos
A1 - Montes-Hernández, German
A1 - Kochovski, Zdravko
A1 - Bienert, Ralf
A1 - Weimann, Karin
A1 - Emmerling, Franziska
A1 - Scoppola, Ernesto
A1 - Van Driessche, Alexander E.S.
T1 - Solution-driven processing of calcium sulfate: The mechanism of the reversible transformation of gypsum to bassanite in brines
N2 - Here, we show that calcium sulfate dihydrate (gypsum) can be directly, rapidly and reversibly converted to calcium sulfate hemihydrate (bassanite) in high salinity solutions (brines). The optimum conditions for the efficient production of bassanite in a short time (<5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the better-known behaviour of the bassanite phase in low-salt environments. In low-salinity aqueous solutions, bassanite is considered to be metastable with respect to gypsum and anhydrite, and therefore gypsum-to-bassanite conversion does not occur in pure water. Interestingly, the high-salinity transformation of gypsum-to-bassanite has been reported by many authors and used in practice for several decades, although its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures was inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline phase for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios.
KW - Industrial and Manufacturing Engineering
KW - Strategy and Management
KW - General Environmental Science
KW - Renewable Energy, Sustainability and the Environment
KW - Building and Construction
KW - Calcium sulfate
KW - Gypsum
KW - Bassanite
KW - Scattering
KW - Raman
KW - In situ
KW - Synchrotron
KW - BESSY
KW - MySpot
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594698
UR - https://www.sciencedirect.com/science/article/pii/S0959652624004591#appsec1
DO - https://doi.org/10.1016/j.jclepro.2024.141012
SN - 0959-6526
VL - 440
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-59469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Edzards, Joshua
A1 - Saßnick, Holger-Dietrich
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Valencia, Ana M.
A1 - Emmerling, Franziska
A1 - Beyer, Sebastian
A1 - Cocchi, Caterina
T1 - Effects of Ligand Substituents on the Character of Zn-Coordination in Zeolitic Imidazolate Frameworks
N2 - Due to their favorable properties and high porosity, zeolitic imidazolate frameworks (ZIFs) have recently received much limelight for key technologies such as energy storage, optoelectronics, sensorics, and catalysis. Despite widespread interest in these materials, fundamental questions regarding the zinc coordination environment remain poorly understood. By focusing on zinc(II)2-methylimidazolate (ZIF-8) and its tetrahedrally coordinated analogues with Br-, Cl-, and H-substitution in the 2-ring position, we aim to clarify how variations in the local environment of Zn impact the charge distribution and the electronic properties of these materials. Our results from densityfunctional theory confirm the presence of a Zn coordinative bond with a large polarization that is quantitatively affected by different substituents on the organic ligand. Moreover, our findings suggest that the variations in the Zn coordination induced by the functionalization have a negligible effect on the electronic structure of the considered compounds. On the other hand, halogen terminations of the ligands lead to distinct electronic contributions in the vicinity of the frontier region which ultimately reduce the band gap size by a few hundred millielectron volts. Experimental results obtained from X-ray absorption spectroscopy (Zn K-edge) confirm the trends predicted by theory and, together with them, contribute to a better understanding of the structure−property relationships that are needed to tailor ZIFs for target applications.
KW - Surfaces
KW - Physical and Theoretical Chemistry
KW - General Energy
KW - Electronic
KW - Coatings and Films
KW - Optical and Magnetic Materials
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589117
DO - https://doi.org/10.1021/acs.jpcc.3c06054
SN - 1932-7447
VL - 127
IS - 43
SP - 21456
EP - 21464
PB - American Chemical Society (ACS)
AN - OPUS4-58911
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zuffa, Caterina
A1 - Cappuccino, Chiara
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Maini, Lucia
T1 - Liquid reagents are not enough for liquid assisted grinding in the synthesis of [(AgBr)(n-pica)]n
N2 - This study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)]n and [(AgBr)2(n-pica)]n to be obtained, and we report the new structures of [(AgBr)2(3-pica)]n and [(AgBr)2(4-pica)]n which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)]n/[(AgBr)2(n-pica)]n by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)]n is kinetically favoured while [(AgBr)2(3-pica)]n is converted into [(AgBr)(3-pica)]n only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile.
KW - Mechanochemistry
KW - Complex
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594755
DO - https://doi.org/10.1039/d3cp04791a
SN - 1463-9076
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheurrell, Kerstin
A1 - B. Martins, Inês C.
A1 - Murray, Claire
A1 - Emmerling, Franziska
T1 - Exploring the role of solvent polarity in mechanochemical Knoevenagel condensation: in situ investigation and isolation of reaction intermediates
N2 - Mechanochemistry has proven to be a highly effective method for the synthesis of organic compounds. We studied the kinetics of the catalyst-free Knoevenagel reaction between 4-nitrobenzaldehyde and malononitrile, activated and driven by ball milling. The reaction was investigated in the absence of solvents (neat grinding) and in the presence of solvents with different polarities (liquid-assisted grinding). The reaction was monitored using time-resolved in situ Raman spectroscopy and powder X-ray diffraction (PXRD). Our results indicate a direct relationship between solvent polarity and reaction kinetics, with higher solvent polarity leading to faster product (2-(4-nitrobenzylidone)malononitrile) formation. For the first time, we were able to isolate and determine the structure of an intermediate 2-(hydroxy(4-nitrophenyl)methyl)malononitrile based on PXRD data.
KW - Physical and Theoretical Chemistry
KW - General Physics and Astronomy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588071
DO - https://doi.org/10.1039/D3CP02883F
SN - 1463-9076
VL - 25
IS - 35
SP - 23637
EP - 23644
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Peters, Stefan
A1 - Kunkel, Benny
A1 - Cakir, Cafer Tufan
A1 - Kabelitz, Anke
A1 - Witte, Steffen
A1 - Bernstein, Thomas
A1 - Bartling, Stephan
A1 - Radtke, Martin
A1 - Emmerling, Franziska
A1 - Abdel-Mageed, Ali Mohamed
A1 - Wohlrab, Sebastian
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Time-, space- and energy-resolved in situ characterization of catalysts by X-ray absorption spectroscopy
N2 - A novel setup for dispersive X-ray absorption spectroscopy (XAS) with simultaneous resolution of space, time and energy for in situ characterization of solid materials is demonstrated.
KW - Dispersive XAS
KW - Catalysis
KW - In situ
KW - Structure analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584924
DO - https://doi.org/10.1039/d3cc03277a
SN - 1359-7345
SP - 1
EP - 4
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Kneiske, Sönke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Ahrens, Mike
A1 - Braun, Thomas
A1 - Emmerling, Franziska
T1 - A fluorolytic sol-gel route to access an amorphous Zr fluoride catalyst: A useful tool for C-F bond activation
N2 - A route to a ZrF4 catalyst active in room temperature Friedel–Crafts and dehydrofluorination reactions was developed via a fluorolytic sol–gel route, which was followed by a postfluorination step using a stream of CHClF2. The behaviour of different Zr(IV) precursors in a sol–gel reaction with anhydrous isopropanol/HF solution was investigated. The subsequent post-fluorination step was optimised in its temperature ramp and confirmed the necessity of a fluorination of the generated xerogels to obtain catalytic activity. The process is discussed in the context of the analysis of the materials using Brunauer–Emmett–Teller analysis (BET), powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The local structure of the amorphous catalyst was elucidated by extended X-ray absorption fine structure spectroscopy (EXAFS).
KW - Catalysis
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - Postfluorination
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593433
DO - https://doi.org/10.1039/D3CY01439H
SN - 2044-4761
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Martin
A1 - Tscheuschner, Georg
A1 - Herrmann, Stefan
A1 - Weller, Michael G.
T1 - Fast Detection of 2,4,6-Trinitrotoluene (TNT) at ppt Level by a Laser-Induced Immunofluorometric Biosensor
N2 - The illegal use of explosives by terrorists and other criminals is an increasing issue in public spaces, such as airports, railway stations, highways, sports venues, theaters, and other large buildings. Security in these environments can be achieved by different means, including the installation of scanners and other analytical devices to detect ultra-small traces of explosives in a very short time-frame to be able to take action as early as possible to prevent the detonation of such devices. Unfortunately, an ideal explosive detection system still does not exist, which means that a compromise is needed in practice. Most detection devices lack the extreme analytical sensitivity, which is nevertheless necessary due to the low vapor pressure of nearly all explosives. In addition, the rate of false positives needs to be virtually zero, which is also very difficult to achieve. Here we present an immunosensor system based on kinetic competition, which is known to be very fast and may even overcome affinity limitation, which impairs the performance of many traditional competitive assays. This immunosensor consists of a monolithic glass column with a vast excess of immobilized hapten, which traps the fluorescently labeled antibody as long as no explosive is present. In the case of the explosive 2,4,6-trinitrotoluene (TNT), some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and chip-based mixing-devices and flow-cells. The system achieved limits of detection of 1 pM (1 ppt) of the fluorescent label and around 100 pM (20 ppt) of TNT. The total assay time is less than 8 min. A cross-reactivity test with 5000 pM solutions showed no signal by pentaerythritol tetranitrate (PETN), 1,3,5-trinitroperhydro-1,3,5-triazine (RDX), and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX). This immunosensor belongs to the most sensitive and fastest detectors for TNT with no significant cross-reactivity by non-related compounds. The consumption of the labeled antibody is surprisingly low: 1 mg of the reagent would be sufficient for more than one year of continuous biosensor operation.
KW - Airport
KW - Aviation
KW - Bombs
KW - Terrorism
KW - Biosensing
KW - Continuous Sensor
KW - High-Speed
KW - Ultrasensitive
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511245
DO - https://doi.org/10.3390/bios10080089
VL - 10
IS - 8
SP - 89
PB - MDPI
CY - Basel
AN - OPUS4-51124
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Costa, Elena
A1 - Climent Terol, Estela
A1 - Gawlitza, Kornelia
A1 - Wan, Wei
A1 - Weller, Michael G.
A1 - Rurack, Knut
T1 - Optimization of analytical assay performance of antibody-gated indicator-releasing mesoporous silica particles
N2 - Antibody-gated indicator delivery (gAID) systems based on mesoporous silica nano- and microparticle scaffolds are a promising class of materials for the sensitive chemical detection of small-molecule analytes in simple test formats such as lateral flow assays (LFAs) or microfluidic chips. Their architecture is reminiscent of drug delivery systems, only that reporter molecules instead of drugs are stored in the voids of a porous host particle. In addition, the pores are closed with macromolecular “caps” through a tailored “gatekeeping” recognition chemistry so that the caps are opened when an analyte has reacted with a “gatekeeper”. The subsequent uncapping leads to a release of a large number of indicator molecules, endowing the system with signal amplification features. Particular benefits of such systems are their modularity and adaptability. With the example of the immunochemical detection of type-I pyrethroids by fluorescent dye-releasing gAID systems, the influence of several tuning modes on the optimisation of such hybrid sensory materials is introduced here. In particular, different mesoporous silica supports (from nano- and microparticles to platelets and short fibres), different functionalisation routes and different loading sequences were assessed. The materials’ performances were evaluated by studying their temporal response behaviour and detection sensitivity, including the tightness of pore closure (through the amount of blank release in the absence of analyte) and the release kinetics. Our results indicate that the better the paratope-accommodating Fab region of the antibody “cap” fits into the host material's pore opening, the better the closing/opening mechanism can be controlled. Because such materials are well-suited for LFAs, performance assessment included a test-strip format besides conventional assays in suspension. In combination with dyes as indicators and smartphones for read-out, simple analytical tests for use by untrained personnel directly at a point-of-need such as an aeroplane cabin can be devised, allowing for sensitivities down to the μg kg−1 range in <5 min with case-required selectivities.
KW - Antibody-gated indicator delivery
KW - Lateral flow assay
KW - SBA-15
KW - SBA-16
KW - Type-I pyrethroids
KW - Phenothrin
KW - Permethrin
KW - Etofenprox
KW - Amplification
KW - Biosensors
KW - Immunoassays
KW - Mesoporous particles
KW - Optical detection
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517053
DO - https://doi.org/10.1039/d0tb00371a
VL - 8
IS - 22
SP - 4950
EP - 4961
PB - Royal Society of Chemistry
AN - OPUS4-51705
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tscheuschner, Georg
A1 - Schwaar, Timm
A1 - Weller, Michael G.
T1 - Fast Confirmation of Antibody Identity by MALDI-TOF MS Fingerprints
N2 - Thousands of antibodies for diagnostic and other analytical purposes are on the market. However, it is often difficult to identify duplicates, reagent changes, and to assign the correct original publications to an antibody. This slows down scientific progress and might even be a cause of irreproducible research and a waste of resources. Recently, activities were started to suggest the sole use of recombinant antibodies in combination with the open communication of their sequence. In this case, such uncertainties should be eliminated. Unfortunately, this approach seems to be rather a long-term vision since the development and manufacturing of recombinant antibodies remain quite expensive in the foreseeable future. Nearly all commercial antibody suppliers also may be reluctant to publish the sequence of their antibodies, since they fear counterfeiting. De novo sequencing of antibodies is also not feasible today for a reagent user without access to the hybridoma clone. Nevertheless, it seems to be crucial for any scientist to have the opportunity to identify an antibody undoubtedly to guarantee the traceability of any research activity using antibodies from a third party as a tool. For this purpose, we developed a method for the identification of antibodies based on a MALDI-TOF MS fingerprint. To circumvent lengthy denaturation, reduction, alkylation, and enzymatic digestion steps, the fragmentation was performed with a simple formic acid hydrolysis step. Eighty-nine unknown monoclonal antibodies were used for this study to examine the feasibility of this approach. Although the molecular assignment of peaks was rarely possible, antibodies could be easily recognized in a blinded test, simply from their mass-spectral fingerprint. A general protocol is given, which could be used without any optimization to generate fingerprints for a database. We want to propose that, in most scientific projects relying critically on antibody reagents, such a fingerprint should be established to prove and document the identity of the used antibodies, as well as to assign a specific reagent to a datasheet of a commercial supplier, public database record, or antibody ID.
KW - Reproducibility
KW - Quality Control
KW - Traceability
KW - Diagnostics
KW - Hybridoma
KW - Monoclonal Antibody
KW - Recombinant Antibody
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506611
DO - https://doi.org/10.3390/antib9020008
SN - 2073-4468
VL - 9
IS - 2
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-50661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ziegler, K.
A1 - Kunert, A. T.
A1 - Reinmuth-Selzle, K.
A1 - Leifke, A. L.
A1 - Widera, D.
A1 - Weller, Michael G.
A1 - Schuppan, D.
A1 - Fröhlich-Nowoisky, J.
A1 - Lucas, K.
A1 - Pöschl, U.
T1 - Chemical modification of pro-inflammatory proteins by peroxynitrite increases activation of TLR4 and NF-κB: Implications for the health effects of air pollution and oxidative stress
N2 - Environmental pollutants like fine particulate matter can cause adverse health effects through oxidative stress and inflammation. Reactive oxygen and nitrogen species (ROS/RNS) such as peroxynitrite can chemically modify proteins, but the effects of such modifications on the immune system and human health are not well understood. In the course of inflammatory processes, the Toll-like receptor 4 (TLR4) can sense damage-associated molecular patterns (DAMPs). Here, we investigate how the TLR4 response and pro-inflammatory potential of the proteinous DAMPs α-Synuclein (α-Syn), heat shock protein 60 (HSP60), and high-mobility-group box 1 protein (HMGB1), which are relevant in neurodegenerative and cardiovascular diseases, changes upon chemical modification with peroxynitrite.
For the peroxynitrite-modified proteins, we found a strongly enhanced activation of TLR4 and the pro-inflammatory transcription factor NF-κB in stable reporter cell lines as well as increased mRNA expression and secretion of the pro-inflammatory cytokines TNF-α, IL-1β, and IL-8 in human monocytes (THP-1). This enhanced activation of innate immunity via TLR4 is mediated by covalent chemical modifications of the studied DAMPs.
Our results show that proteinous DAMPs modified by peroxynitrite more potently amplify inflammation via TLR4 activation than the native DAMPs, and provide first evidence that such modifications can directly enhance innate immune responses via a defined receptor. These findings suggest that environmental pollutants and related ROS/RNS may play a role in promoting acute and chronic inflammatory disorders by structurally modifying the body's own DAMPs. This may have important consequences for chronic neurodegenerative, cardiovascular or gastrointestinal diseases that are prevalent in modern societies, and calls for action, to improve air quality and climate in the Anthropocene.
KW - Protein nitration
KW - Protein oligomerization
KW - Damage-associated molecular patterns (DAMPs)
KW - Pattern recognition receptor
KW - Anthropocene
KW - Environmental pollutants
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517128
DO - https://doi.org/10.1016/j.redox.2020.101581
VL - 37
SP - 101581
PB - Elsevier B.V.
AN - OPUS4-51712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brangsch, J.
A1 - Reimann, C.
A1 - Kaufmann, Jan Ole
A1 - Adams, L. C.
A1 - Onthank, D.
A1 - Thöne-Reineke, C.
A1 - Robinson, S.
A1 - Ponader, Marco
A1 - Weller, Michael G.
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Botnar, R.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Molecular MR-Imaging for Noninvasive Quantification of the Anti-Inflammatory Effect of Targeting Interleukin-1β in a Mouse Model of Aortic Aneurysm
N2 - Background:
Molecular-MRI is a promising imaging modality for the assessment of abdominal aortic aneurysms (AAAs). Interleukin-1β (IL-1β) represents a new therapeutic tool for AAA-treatment, since pro-inflammatory cytokines are key-mediators of inflammation. This study investigates the potential of molecular-MRI to evaluate therapeutic effects of an anti-IL-1β-therapy on AAA-formation in a mouse-model.
Methods:
Osmotic-minipumps were implanted in apolipoprotein-deficient-mice (N = 27). One group (Ang-II+01BSUR group, n = 9) was infused with angiotensin-II (Ang-II) for 4 weeks and received an anti-murine IL-1β-antibody (01BSUR) 3 times. One group (Ang-II-group, n = 9) was infused with Ang-II for 4 weeks but received no treatment. Control-group (n = 9) was infused with saline and received no treatment. MR-imaging was performed using an elastin-specific gadolinium-based-probe (0.2 mmol/kg).
Results:
Mice of the Ang-II+01BSUR-group showed a lower aortic-diameter compared to mice of the Ang-II-group and control mice (p < 0.05). Using the elastin-specific-probe, a significant decrease in elastin-destruction was observed in mice of the Ang-II+01BSUR-group. In vivo MR-measurements correlated well with histopathology (y = 0.34x-13.81, R2 = 0.84, p < 0.05), ICP-MS (y = 0.02x+2.39; R2 = 0.81, p < 0.05) and LA-ICP-MS. Immunofluorescence and western-blotting confirmed a reduced IL-1β-expression.
Conclusions:
Molecular-MRI enables the early visualization and quantification of the anti-inflammatory-effects of an IL-1β-inhibitor in a mouse-model of AAAs. Responders and non-responders could be identified early after the initiation of the therapy using molecular-MRI.
KW - Cardiovascular
KW - Molecular-MRI
KW - Magnetic resonance imaging
KW - Gadolinium-based contrast agent
KW - Elastin-specific contrast agent ESMA
KW - Gadovist
KW - Gadofosveset
KW - MR Angiography
KW - Inductively Coupled Mass Spectroscopy
KW - Element Specific Bioimaging Using Laser Ablation
KW - Visualization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517150
DO - https://doi.org/10.1177/1536012120961875
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
VL - 19
SP - 61875
PB - SAGE
AN - OPUS4-51715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Biyikal, Mustafa
A1 - Gröninger, Delia
A1 - Weller, Michael G.
A1 - Martínez Mánez, R.
A1 - Rurack, Knut
T1 - Multiplex‐Nachweis von Analyten auf einem einzelnen Teststreifen mit Antikörper‐gesteuerten und Indikator freisetzenden mesoporösen Nanopartikeln
N2 - Vor dem Hintergrund der einzigartigen Modularität, hohen Empfindlichkeit und Selektivität von Antikörper‐gesteuerten Indikatorfreisetzungssystemen (gAID‐Systemen) wurde hier ein Multiplex‐Assay für drei organische Explosivstoffmoleküle (TATP, TNT, PETN) entwickelt, der es erlaubt, die Analyten gleichzeitig in flüssiger Phase mit einem einzelnen Teststreifen und einem Fluoreszenzlesegerät bzw. Smartphone als Detektor in Konzentrationen bis in den unteren ppb‐Bereich in <5 min nachzuweisen. Alle drei Systeme, darunter die hier neu entwickelten Systeme für TNT und PETN, tolerieren zudem nicht nur gepufferte wässrige Modelllösungen, sondern auch komplexere Matrices. Neben einem konventionellen Teststreifen mit einem Kanal erlaubte uns die Anwendung von Wachsdrucktechnologie das Herstellen von mehrkanaligen Streifen mit vergleichbarer analytischer Leistungsfähigkeit, was das enorme Potenzial der modular aufgebauten, hybriden Biosensormaterialien im Hinblick auf eine für den Endanwender maßgeschneiderte Vor‐Ort‐Analytik unterstreicht.
KW - Multiplex
KW - Gesteuerten Nanopartikeln
KW - Explosiven
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518431
DO - https://doi.org/10.1002/ange.202009000
SN - 1521-3757
SN - 0044-8249
VL - 132
IS - 52
SP - 24071
EP - 24078
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-51843
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Climent Terol, Estela
A1 - Biyikal, Mustafa
A1 - Gröninger, Delia
A1 - Weller, Michael G.
A1 - Martínez Mánez, R.
A1 - Rurack, Knut
ED - Climent Terol, Estela
T1 - Multiplexed Detection of Analytes on Single Test Strips with Antibody-Gated Indicator-Releasing Mesoporous Nanoparticles
N2 - Rapid testing methods for the use directly at apointof need are expected to unfold their true potential especiallywhen offering adequate capabilities for the simultaneousmeasurement of multiple analytes of interest. Considering theunique modularity,high sensitivity,and selectivity of antibody-gated indicator delivery (gAID) systems,amultiplexed assayfor three small-molecule explosives (TATP, TNT,PETN) wasthus developed, allowing to detect the analytes simultaneouslywith asingle test strip at lower ppb concentrations in the liquidphase in < 5min using afluorescence reader or asmartphonefor readout. While the TNT and PETN systems were newlydeveloped here,all the three systems also tolerated harshermatrices than buffered aqueous model solutions.Besidesasingle-track strip,the outstanding modularity of the hybridbiosensor materials in combination with strip-patterningtechnologies allowed us to obtain amultichannel strip inastraightforwardmanner,offering comparable analyticalperformance while allowing to be tailored even more to theusersneed.
KW - Multiplexing
KW - Explosives detection
KW - Gated materials
KW - Fluorescence
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518424
DO - https://doi.org/10.1002/anie.202009000
SN - 1433-7851
SN - 1521-3773
VL - 59
IS - 52
SP - 23862
EP - 23869
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-51842
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weller, Michael G.
T1 - The Protocol Gap
N2 - Although peer review is considered one of the main pillars of modern science, experimental methods and protocols seem to be not a rigorous subject of this process in many papers. Commercial equipment, test kits, labeling kits, previously published concepts, and standard protocols are often considered to be not worth a detailed description or validation. Even more disturbing is the extremely biased citation behavior in this context, which sometimes leads to surrogate citations to avoid low-impact journals, preprints, or to indicate traditional practices. This article describes some of these surprising habits and suggests some measures to avoid the most unpleasant effects, which in the long term may undermine the credibility of science as a whole.
KW - Validation
KW - Peer review
KW - Experiment
KW - Documentation
KW - Scientific publication
KW - Reproducibility crisis
KW - Replication crisis
KW - Trust
KW - Citation
KW - References
KW - Surrogate citations
KW - Impact
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521440
DO - https://doi.org/10.3390/mps4010012
SN - 2409-9279
VL - 4
IS - 1
SP - 1
EP - 5
PB - MDPI
CY - Basel
AN - OPUS4-52144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Sagar
A1 - Dolai, Malay
A1 - Nanda Goswami, Juli
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Drew, Michael G. B.
A1 - Chattopadhyay, Shouvik
A1 - Sarkar, Rabi Sankar
A1 - Sunil, Appu
A1 - Novitchi, Ghenadie
A1 - Moreno-Pineda, Eufemio
A1 - Wernsdorfer, Wolfgang
T1 - From strong to weak interaction: Reconciling SQUID and μSQUID-EPR data in anomalous Co(ii) dimers
N2 - Magnetic molecules have been proposed as scaffolds for novel quantum technologies, ranging from quantum sensing and quantum memory to multilevel quantum bits (qudits) and fault-tolerant quantum computation. Integration of magnetic molecules into cutting-edge applications hinges on a deep understanding and tunability of their spin states. To date, the strategic manipulation of the local environment of the ion and careful selection of the magnetic core have enabled the desired tunability and scalability of the spin states. For such goals, however, extracting the anisotropic parameters that dictate the characteristics of the Spin Hamiltonian is challenging, especially for molecules consisting of multiple magnetic cores. We address these challenges by studying two cobalt(II) dinuclear systems, complicated by inherent spin–orbit coupling. We explore the magnetic properties of these systems in two temperature regimes: (i) at sub-Kelvin temperatures employing single crystals at 30 mK using a unique μSQUID-EPR technique that examines the microwave absorption peaks in the magnetisation data and their variation with field angle and frequency; and (ii) in bulk employing convectional SQUID magnetometry above 2 K i.e., χMT(T) and M(H). Unexpectedly, sub-Kelvin temperature investigations reveal a negligible interaction, whereas the SQUID data reveal a much stronger interaction between the Co(II) ions. An understanding of these data is developed based on a strong coupling model and the coupling of two moieties with a spin-effective ground state.
KW - cOBALT(II)-complex
KW - In situ complex formation
KW - Magnetic property
KW - Crystal structure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641421
DO - https://doi.org/10.1039/D5QI01387A
SN - 2052-1553
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishra, Rajesh K.
A1 - Minussi, F.B.
A1 - Kumari, Priyanka
A1 - Shahi, Rohit R.
A1 - Yadav, R.P.
A1 - Emmerling, Franziska
A1 - Araújo, E.B.
T1 - Effect of sintering temperature on structural, microstructural, and dielectric properties of (Co0.2Fe0.2Ni0.2Al0.2Ti0.2)3O4 multi-cations high entropy oxides
N2 - The study reports the effect of sintering temperature on structural, microstructural, and dielectric properties of (Co0.2Fe0.2Ni0.2Al0.2Ti0.2)3O4 spinel high-entropy oxides (HEOs) synthesized through the solid-state mechanochemistry method. The sintering of the ceramic powders was accomplished at three different temperatures (1000 ◦C, 1100 ◦C, and 1250 ◦C), followed by air quenching. XRD analysis along with Le-Bail refinement confirms that 1100 ◦C and 1250 ◦C sintered oxides comprised of a single cubic spinel phase (Fd3m), while 1000 ◦C sintered oxide contains constituent oxides and a spinel phase. The phase formation of oxides sintered at 1100 ◦C and 1250 ◦C has also been confirmed by Raman spectroscopic analysis. Microstructural analysis revealed that the aggregated particle size increases with the rise in sintering temperature. With the change in sintering temperature, the dielectric behavior of the ceramic changed extensively. The 1100 ◦C sintered ceramic exhibits high frequency-dependent behavior, whereas the 1250 ◦C sintered ceramic yields low frequency-dependent behavior. The 1250 ◦C sintered HEO exhibits low-loss tangent (tan δ = 0.01) with higher dielectric permittivity (εʹ = 44) at high frequency (1 MHz) compared to the 1100 ◦C sintered ceramic and many other conventional dielectrics.
Fractal concept and impedance analysis have been employed to correlate the microstructure-dielectric property relation of (Co0.2Fe0.2Ni0.2Al0.2Ti0.2)3O4 spinel HEOs. The found Hurst exponent values for both different temperature-sintered HEOs are less than 0.5, indicating the anti-persistent behavior. This signifies that the height variations at neighboring pixels are negatively correlated. The present work is of fundamental importance in employing fractal analysis for the first time on spinel HEOs and correlating their properties. It also shows that processing conditions can effectively tailor the dielectric properties of the materials.
KW - Multi-cations high entropy oxide
KW - Mechanochemistry
KW - Spinel structure
KW - Fractal and impedance spectroscopic analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647584
DO - https://doi.org/10.1016/j.ceramint.2025.09.256
SN - 0272-8842
VL - 51
IS - 27
SP - 55341
EP - 55354
PB - Elsevier Ltd.
AN - OPUS4-64758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Standl, Jacob
A1 - Ryll, Tom W.
A1 - Schwab, Alexander
A1 - Prinz, Carsten
A1 - Wolf, Jakob B.
A1 - Kruschwitz, Sabine
A1 - Emmerling, Franziska
A1 - Völker, Christoph
A1 - Stawski, Tomasz M.
T1 - High-Entropy Phosphate Synthesis: Advancements through Automation and Sequential Learning Optimization
N2 - Transition metal phosphates (TMPs) are extensively explored for electrochemical and catalytical applications due to their structural versatility and chemical stability. Within this material class, novel high-entropy metal phosphates (HEMPs)─containing multiple transition metals combined into a single-phase structure─are particularly promising, as their compositional complexity can significantly enhance functional properties. However, the discovery of suitable HEMP compositions is hindered by the vast compositional design space and complex or very specific synthesis conditions. Here, we present a data-driven strategy combining automated wet-chemical synthesis with a Sequential Learning App for Materials Discovery (SLAMD) framework (Random Forest regression model) to efficiently explore and optimize HEMP compositions. Using a limited set of initial experiments, we identified multimetal compositions in a single-phase crystalline solid. The model successfully predicted a novel Co0.3Ni0.3Fe0.2Cd0.1Mn0.1 phosphate octahydrate phase, validated experimentally, demonstrating the effectiveness of the machine learning approach. This work highlights the potential of integrating automated synthesis platforms with data-driven algorithms to accelerate the discovery of high-entropy materials, offering an efficient design pathway to advanced functional materials.
KW - Metal phosphates
KW - High entropy
KW - Sequential learning
KW - Automated synthesis
KW - MAP
KW - Random forest
KW - Machine learning
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641554
DO - https://doi.org/10.1021/acs.cgd.5c00549
SN - 1528-7483
VL - 25
IS - 19
SP - 7989
EP - 8001
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-64155
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Batteas, James
A1 - Blank, Kerstin G.
A1 - Colacino, Evelina
A1 - Emmerling, Franziska
A1 - Friščić, Tomislav
A1 - Mack, James
A1 - Moore, Jeffrey
A1 - Rivas, Maria Elena
A1 - Tysoe, Wilfred
T1 - Moving mechanochemistry forward
N2 - Arguably mechanochemistry is one of the oldest, and at the same time one of the newest, areas of chemistry. One of the oldest, because it has been theorized that early hominids were able to develop rapidly due to their ability to heat and mechanically process their food to make it easier to digest. Old, because the ancient Greeks knew that mechanically activating stones (consisting of cinnabar) with vinegar in a copper pestle and mortar caused them to convert into mercury. We might be forgiven for thinking that this could have led our alchemical forbears to wonder if there were other stones that might also be persuaded to convert into gold. Early chemical luminaries such as Michael Faraday and Wilhelm Röntgen dabbled in mechanochemistry. However, in the late 19th and early 20th centuries, the field developed separately in many areas. Perhaps most significantly, synthetic chemists realized that reactions could be carried out with surprisingly high yields and selectivities by shaking them in a ball mill, and that they could even make novel compounds that their colleagues just using heat were not able to. Physicists were mechanically rearranging atoms into new configurations (i.e., doing chemistry) using exotic means such as atomic force microscope tips and optical tweezers. Scientists and engineers studying the formation of lubricious and anti-wear films realized that they were mechanochemically formed. Biochemists found molecular motor proteins, such as myosin and kinesin, that were able to convert chemical energy into motion or, vice versa, mechanical energy into the biochemical energy storage molecule adenosine triphosphate. In 2023, this confluence of advances convinced the Royal Society of Chemistry that the time was ripe to establish a new journal dedicated to the field of mechanochemistry. It is rare that a journal has the privilege of helping to create a new sub-branch of chemistry but, having done so, it has the obligation of helping to define the field and, optimistically, suggesting how the field might develop. This editorial has two major goals. The first is to bring to the attention of the scientific community the challenges faced by the field to set people thinking about how they might contribute and, second, to form the basis for more thorough discussions in the future. The sub-topics below outline current thoughts brought forward from members of our editorial board. We lay out areas and topics here with the intent of establishing a new editorial series, which we invite the community to contribute to, and outline topics and hopefully lay out challenges, which will enable us as a community to come together to move mechanochemistry forward.
KW - Mechanochemistry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646086
DO - https://doi.org/10.1039/d4mr90021a
SN - 2976-8683
VL - 2
IS - 1
SP - 10
EP - 19
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ferreira, Daniela R.
A1 - Portet, Anaïs
A1 - Alves, Paula C.
A1 - Rijo, Patrícia
A1 - Gomes, Clara S. B.
A1 - Duarte, M. Teresa
A1 - Halasz, Ivan
A1 - Colacino, Evelina
A1 - Emmerling, Franziska
A1 - André, Vânia
T1 - Modulating the crystalline forms of silver–sulfadiazine complexes by mechanochemistry
N2 - Mechanochemical synthesis of pharmaceutical compounds has gained significant attention due to its potential to overcome traditional synthetic challenges while offering the possibility of improving the physicochemical properties of drugs. This study delves into the mechanochemical synthesis of silver sulfadiazine (AgSD) coordination compounds, obtained under different mechanochemical stress and processing conditions. The aim of this work was to investigate the influence of mechanochemical conditions on the selectivity in the preparation of AgSD coordination compounds. Through a series of experiments, we demonstrate the successful synthesis of two different AgSD coordination networks, using high-energy ball milling. By strategically manipulating the starting materials and milling parameters — including milling time, milling frequency, type of mechanical stress (as determined by different milling devices), and the presence of co-milling agents — we were able to control the product outcome. As a result, we achieved two different forms of silver-sulfadiazine metal frameworks, one of which was not previously disclosed. The crystal structure of the new form, obtained from high resolution PXRD synchrotron data, was compared with the previously known structure of a silver sulfadiazine compound. The in-depth antimicrobial activity systematic study of these AgSD forms on the generic systems showed increased antibacterial activity when compared to sulfadiazine. This research sheds light on the mechanochemical synthesis of silver sulfadiazine complexes. The obtained knowledge may guide the development of novel synthetic strategies for other drug molecules, leading to improved drug performance, stability, and therapeutic outcomes.
KW - Mechanochemistry
KW - Structure solution
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646099
DO - https://doi.org/10.1039/d5ce00572h
SN - 1466-8033
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez-Sánchez, Noelia
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Ballesteros, Menta
A1 - Ruiz Salvador, A. Rabdel
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Mechanochemical ZIF-9 formation: in situ analysis and photocatalytic enhancement evaluation
N2 - Efficient treatment of persistent pollutants in wastewater is crucial for sustainable water management and environmental protection. This study addresses this challenge by investigating the mechanochemical synthesis and photocatalytic performance of ZIF-9, a cobalt-based zeolitic imidazolate framework. Using synchrotron-based powder X-ray diffraction, we provide real-time insights into the formation dynamics of ZIF-9 during mechanosynthesis. Our results show that mechanochemically synthesised ZIF-9 exhibits superior photocatalytic activity compared to its solvothermally prepared counterpart, achieving a 2-fold increase in methylene blue degradation rate. This research not only advances our understanding of the synthesis and properties of ZIF-9, but also demonstrates the potential of mechanochemical approaches in the development of high-performance, sustainably produced materials for water treatment and other environmental applications.
KW - MOFs
KW - ZIF
KW - Time-resolved in situ investigation
KW - Photocatalysis synchrotron X-ray powder diffraction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641416
DO - https://doi.org/10.1039/D4MR00114A
SN - 2976-8683
VL - 2
IS - 1
SP - 116
EP - 126
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-64141
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lopes, Chrystal
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Leyssens, Tom
A1 - Dupray, Valérie
A1 - Brandel, Clement
A1 - Cartigny, Yohann
T1 - Efficient racemization of the pharmaceutical compound Levetiracetam using solvent-free mechanochemistry
N2 - We present the racemization of an active pharmaceutical ingredient Levetiracetam using a novel approach. We demonstrate the design of a 100% solvent-free process that proceeds by high energy milling inside a regular mixer mill. The kinetics of the racemization process is drastically improved compared to the solution-based approach and illustrates the tremendous potential of mechanochemistry. In this study, we highlight the importance of mixing efficiency regarding data reproducibility, and we show, in particular, that water contamination has a negative impact on the reaction rate. Moreover, in situ X-ray diffraction gives us first insights into the mechanisms involved in the solid state during the mechanochemical racemization process.
KW - Mechanochemistry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646108
DO - https://doi.org/10.1039/d4mr00103f
SN - 2976-8683
VL - 2
IS - 1
SP - 83
EP - 90
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64610
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Macchietti, Laura
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Braga, Dario
A1 - Grepioni, Fabrizia
T1 - Deriving kinetic insights from mechanochemically synthesized compounds using multivariate analysis (MCR-ALS) of powder X-ray diffraction data
N2 - Kinetics information on the progress of the mechanochemical reactions is key to their understanding and subsequent scale-up. For crystalline materials, the most robust and tested method for obtaining kinetic data is the Quantitative Phase Analysis (QPA) via Rietveld refinement. In this work, we tested the feasibility of the Multivariate Curve Resolution-Alternating Least Squares (MCR-ALS) method on powder X-ray diffraction (PXRD) data of mechanochemical processes by studying the system theophylline (TP) and malonic acid (MA) in a 1 : 1 stoichiometric ratio at different milling conditions. We have highlighted the strengths and weaknesses of the MCR-ALS method, and we demonstrated why it may be an alternative route to obtain quantitative information on mechanochemical kinetics.
KW - Mechanochemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646115
DO - https://doi.org/10.1039/d3mr00013c
SN - 2976-8683
VL - 1
IS - 1
SP - 106
EP - 115
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavlidis, Sotirios
A1 - Teutloff, Christian
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Krause, Konstantin B.
A1 - Emmerling, Franziska
A1 - Bittl, Robert
A1 - Abbenseth, Josh
T1 - A Crystalline Bismuth(II) Radical Anion: Synthesis, Characterization, and Reactivity
N2 - AbstractWe report the synthesis of a planarized tris‐amidobismuthane supported by a rigid, bulky NNN pincer ligand, which enforces a T‐shaped geometry at the bismuth center. The Bi(NNN) complex features a low‐lying LUMO with distinct Bi(6p) orbital character as shown by DFT calculations. Cyclic voltammetry reveals a fully reversible one‐electron reduction at E1/2 = –1.85 V versus Fc0/+ in THF. Chemical reduction with KC8 in the presence of 4,7,13,16,21,24‐hexaoxa‐1,10‐diazabicyclo[8.8.8]hexacosane (222‐crypt) enables the isolation of an unprecedented Bi(II) radical anion in high isolated yields. Multi‐frequency EPR, X‐ray absorption spectroscopy and SQUID magnetometry complemented by theoretical calculations confirm localization of the unpaired electron on the bismuth center. Preliminary reactivity studies display radical reactivity as shown by single‐electron transfer chemistry and radical coupling reactions.
KW - Bi(III)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644143
DO - https://doi.org/10.1002/anie.202515545
SN - 1433-7851
VL - 64
IS - 49
SP - 1
EP - 6
PB - Wiley VHC-Verlag
AN - OPUS4-64414
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chapartegui-Arias, Ander
A1 - Raysyan, A.
A1 - Belenguer, A. M.
A1 - Jaeger, Carsten
A1 - Tchipilov, Teodor
A1 - Prinz, Carsten
A1 - Abad Andrade, Carlos Enrique
A1 - Beyer, S.
A1 - Schneider, Rudolf
A1 - Emmerling, Franziska
T1 - Tailored mobility in a zeolite imidazolate framework (ZIF) antibody conjugate
N2 - Zeolitic imidazolate framework (ZIF) hybrid fluorescent nanoparticles and ZIF antibody conjugates have been synthesized, characterized, and employed in lateral-flow immunoassay (LFIA). The bright fluorescence of the conjugates and the possibility to tailor their mobility gives a huge potential for diagnostic assays. An enzyme-linked immunosorbent assay (ELISA) with horseradish peroxidase (HRP) as label, proved the integrity, stability, and dispersibility of the antibody conjugates, LC-MS/MS provided evidence that a covalent link was established between these metal-organic frameworks and lysine residues in IgG antibodies.
KW - ZIF
KW - ELISA
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532096
DO - https://doi.org/10.1002/chem.202100803
SN - 0947-6539
SN - 1521-3765
VL - 27
IS - 36
SP - 9414
EP - 9421
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-53209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Casali, L.
A1 - Broll, V.
A1 - Ciurili, S.
A1 - Braga, D.
A1 - Emmerling, Franziska
A1 - Gepioni, F.
T1 - Facilitating Nitrification Inhibition through Green, Mechanochemical Synthesis of a Novel Nitrapyrin Complex
N2 - Nitrapyrin (NP) is applied to cultivated soils to inhibit the enzymatic activity of ammonia monooxygenase (AMO), but its poor aqueous solubility and high volatility severely limit its application. β-Cyclodextrin (β-CD) is commonly used to form inclusion complexes with hydrophobic molecules, improving water solubility and stability upon complexation. Here we report on the mechanochemical synthesis of the inclusion complex β-CD·NP, characterized via a combination of solid-state techniques, including exsitu and in situ X-ray diffraction, Raman and NMR spectroscopies, transmission electron microscopy, and energy dispersive X-ray spectroscopy. The pure inhibitor NP was also structurally characterized. The β-CD·NP complex presents improved solubility and thermal stability, and still inhibits the enzymatic activity of AMO with high efficacy. All results indicate that the inclusion of NP into β-CD represents a viable route for the preparation of a novel class of inhibitors, with improved properties related to stability, water solubility, and good inhibition activity.
KW - Mechanochemistry
KW - Nitrification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537154
DO - https://doi.org/10.1021/acs.cgd.1c00681
SN - 1528-7505
VL - 21
IS - 10
SP - 5792
EP - 5799
PB - ACS Publications
AN - OPUS4-53715
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heilmann, Maria
A1 - Prinz, Carsten
A1 - Bienert, Ralf
A1 - Wendt, R.
A1 - Kunkel, B.
A1 - Radnik, Jörg
A1 - Hoell, A.
A1 - Wohlrab, S.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
T1 - Size-Tunable Ni–Cu Core–Shell Nanoparticles—Structure, Composition, and Catalytic Activity for the Reverse Water–Gas Shift Reaction
N2 - A facile and efficient methodology is described for the solvothermal synthesis of size-tunable, stable, and uniform NiCu core–shell nanoparticles (NPs) for application in catalysis. The diameter of the NPs is tuned in a range from 6 nm to 30 nm and to adjust the Ni:Cu ratio from 30:1 to 1:1. Furthermore, the influence of different reaction parameters on the final NPs is studied. The NPs are structurally characterized by a method combination of transmission electron microscopy, anomalous small-angle X-ray scattering, X-ray absorption fine structure, and X-ray photoelectron spectroscopy. Using these analytical methods, it is possible to elucidate a core–shell–shell structure of all particles and their chemical composition. In all cases, a depletion from the core to the shell is observed, with the core consisting of NiCu alloy, surrounded by an inner Ni-rich shell and an outer NiO shell. The SiO2-supported NiCu core–shell NPs show pronounced selectivity of >99% for CO in the catalytic reduction of CO2 to CO using hydrogen as reactant (reverse water–gas shift reaction) independent of size and Ni:Cu ratio.
KW - Nanoparticles
KW - Core-shell
KW - Catalysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543606
DO - https://doi.org/10.1002/adem.202101308
SN - 1438-1656
SP - 1
EP - 13
PB - Wiley VCH
AN - OPUS4-54360
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Topolniak, Ievgeniia
A1 - Silbernagl, Dorothee
A1 - Altmann, Korinna
A1 - Sturm, Heinz
T1 - Long-time behavior of surface properties of microstructures fabricated by multiphoton lithography
N2 - The multiphoton lithography (MPL) technique represents the future of 3D microprinting, enabling the production of complex microscale objects with high precision. Although the MPL fabrication parameters are widely evaluated and discussed, not much attention has been given to the microscopic properties of 3D objects with respect to their surface properties and time-dependent stability. These properties are of crucial importance when it comes to the safe and durable use of these structures in biomedical applications. In this work, we investigate the surface properties of the MPL-produced SZ2080 polymeric microstructures with regard to the physical aging processes during the post-production stage. The influence of aging on the polymeric microstructures was investigated by means of Atomic Force Microscopy (AFM) and X-ray Photoelectron Spectroscopy (XPS). As a result, a time-dependent change in Young’s Modulus, plastic deformation, and adhesion and their correlation to the development in chemical composition of the surface of MPL-microstructures are evaluated. The results presented here are valuable for the application of MPL-fabricated 3D objects in general, but especially in medical technology as they give detailed information of the physical and chemical time-dependent dynamic behavior of MPL-printed surfaces and thus their suitability and performance in biological systems.
KW - Multiphoton lithography
KW - Additive manufacturing
KW - Microfabrication
KW - SZ2080 negative photo-resist
KW - Young´s modulus
KW - Aging
KW - Surface properties
KW - X-ray photoelectron spectroscopy
KW - Atomic force microscopy
KW - Force-distance-curve
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542166
DO - https://doi.org/10.3390/nano11123285
SN - 2079-4991
VL - 11
IS - 12
SP - 1
EP - 12
PB - MDPI
CY - Basel
AN - OPUS4-54216
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Axel
A1 - Altmann, Korinna
A1 - Kocher, B.
A1 - Braun, U.
T1 - Determination of tire wear markers in soil samples and their distribution in a roadside soil
N2 - Tire wear (TW) constitutes a significant source of microplastic in terrestrial ecosystems. It is known that particles emitted by roads can have an effect up to 100 m into adjacent areas. Here, we apply for the first-time thermal extraction desorption gas chromatography-mass spectrometry (TED-GC/MS) to determine TW in soil samples by detection of thermal decomposition products of styrene-butadiene rubber (SBR), without additional enrichment. Additionally, zinc contents were determined as an elemental marker for TW. Mixed soil samples were taken along three transects along a German motorway in 0.3, 2.0, and 5.0 m distance from the road. Sampling depths were 0–2, 2–5, 5–10, and 10–20 cm. Four fine fractions, 1 000–500, 500–100, 100–50, and <50 μm, were analyzed.
TW contents based on SBR ranged from 155 to 15 898 mg kg−1. TW contents based on zinc were between 413 and 44 812 mg kg−1. Comparison of individual values of SBR and zinc reveals SBR as a more specific marker. Results confirm that most TW ends up in the topsoil within a 2 m distance.
The sampling strategy resulted in representative data for a larger area. Standard deviations of quadruple TED-GC/MS determination of SBR were <10% for all grain size fractions. TED-GC/MS is a suitable analytical tool for determining TW in soil samples without the use of toxic chemicals, enrichment, or special sample preparation.
KW - Microplastic
KW - TED-GC/MS
KW - Tire wear
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543344
DO - https://doi.org/10.1016/j.chemosphere.2022.133653
VL - 294
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-54334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yusenko, Kirill
A1 - Kabelitz, Anke
A1 - Schokel, Alexander
A1 - Wagner, Ralf
A1 - Prinz, Carsten
A1 - Kemnitz, E
A1 - Emmerling, Franziska
A1 - Krahl, Thoralf
A1 - de Oliveira Guilherme Buzanich, Ana
T1 - Local Structure of Europium-Doped Luminescent Strontium Fluoride Nanoparticles: Comparative X-ray Absorption Spectroscopy and Diffraction Study
N2 - Rare-earth based luminescent materials are key functional components for the rational design of light-conversion smart devices. Stable Eu3+-doped strontium fluoride (SrF2) nanoparticles were prepared at room temperature in ethylene glycol. Their luminescence depends on the Eu content and changes after heat treatment. The crystallinity of heat-treated material increases in comparison with as-synthesized samples. Particles were investigated in solution using X-ray diffraction, small-angle X-ray scattering, and X-ray spectroscopy. After heat treatment, the size of the disordered nanoparticles increases together with a change of their local structure. Interstitial fluoride ions can be localized near Eu3+ ions. Therefore, non-radiative relaxation from other mechanisms is decreased. Knowledge about the cation distribution is key information for understanding the luminescence properties of any material.
KW - SrF2
KW - EXAFS
KW - Eu
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540094
DO - https://doi.org/10.1002/cnma.202100281
VL - 7
IS - 11
SP - 1221
EP - 1229
PB - Wiley Online Library
AN - OPUS4-54009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lampronti, G.
A1 - Michalchuk, Adam
A1 - Mazzeo, P.
A1 - Belenguer, Ana
A1 - Sanders, J. K. M.
A1 - Bacchi, A.
A1 - Emmerling, Franziska
T1 - Changing the game of time resolved X-ray diffraction on the mechanochemistry playground by downsizing
N2 - Time resolved in situ (TRIS) monitoring has revolutionised the study of mechanochemical transformations but has been limited by available data quality. Here we report how a combination of miniaturised grinding jars together with innovations in X-ray powder diffraction data collection and state-of-the-art analysis strategies transform the power of TRIS synchrotron mechanochemical experiments. Accurate phase compositions, comparable to those obtained by ex situ measurements, can be obtained with small sample loadings. Moreover, microstructural parameters (crystal size and microstrain) can be also determined with high confidence. This strategy applies to all chemistries, is readily implemented, and yields high-quality diffraction data even using a low energy synchrotron source. This offers a direct avenue towards the mechanochemical investigation of reactions comprising scarce, expensive, or toxic compounds. Our strategy is applied to model systems, including inorganic, metal-organic, and organic mechanosyntheses, resolves previously misinterpreted mechanisms in mechanochemical syntheses, and promises broad, new directions for mechanochemical research.
KW - Mechanochemistry
KW - Synchrotron radiation
KW - Material synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535932
DO - https://doi.org/10.1038/s41467-021-26264-1
SN - 2041-1723
VL - 12
IS - 1
SP - 1
EP - 9
PB - Nature Publishing Group
CY - London
AN - OPUS4-53593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feiler, Torvid
A1 - Michalchuk, Adam
A1 - Schröder, V.
A1 - List-Kratochvil, E.
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Elastic Flexibility in an Optically Active Naphthalidenimine-Based Single Crystal
N2 - Organic single crystals that combine mechanical flexibility and optical properties are important for developing flexible optical devices, but examples of such crystals remain scarce. Both mechanical flexibility and optical activity depend on the underlying crystal packing and the nature of the intermolecular interactions present in the solid state. Hence, both properties can be expected to be tunable by small chemical modifications to the organic molecule. By incorporating a chlorine atom, a reportedly mechanically flexible crystal of (E)-1-(4-bromo-phenyl)iminomethyl-2-hydroxylnaphthalene (BPIN) produces (E)-1-(4-bromo-2-chloro-phenyl)iminomethyl-2-hydroxyl-naphthalene (BCPIN). BCPIN crystals show elastic bending similar to BPIN upon mechanical stress, but exhibit a remarkable difference in their optical properties as a result of the chemical modification to the backbone of the organic molecule. This work thus demonstrates that the optical properties and mechanical flexibility of molecular materials can, in principle, be tuned independently.
KW - Elastic Crystal
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539040
DO - https://doi.org/10.3390/cryst11111397
VL - 11
IS - 11
SP - 1397
PB - MDPI
AN - OPUS4-53904
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gernhard, M.
A1 - Rautenberg, Max
A1 - Hörner, G.
A1 - Weber, B.
A1 - Emmerling, Franziska
A1 - Roth, C.
T1 - Mechanochemical Synthesis as a Greener Way to ProduceIron-based Oxygen Reduction Catalysts
N2 - Iron-based catalysts have been reported manifold and studied as platinum group metal (PGM) free alternatives for the catalysis of the oxygen reduction reaction (ORR). However, their sustainable preparation by greener synthesis approaches is usually not discussed. In this work, we propose a new method for the sustainable preparation of such catalysts by using a mechanochemical approach, with no solvents and non-toxic chemicals. The materials obtained from low temperature carbonization (700 °C) exhibit considerable and stable catalytic performance for ORR in alkaline medium. A catalyst obtained
from iron hydroxide, tryptophan, dicyandiamide, and ammonium nitrate shows the best electrocatalytic Performance with an overpotential of 921 mV vs. RHE at 0.1 mA/cm2 and an electron transfer number of 3.4.
KW - PGM-free catalyst
KW - Oxygen Reduction Reaction
KW - AEMFC
KW - Mössbauer Spectroscopy
KW - Sustainable Synthesis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535326
DO - https://doi.org/10.1002/zaac.202100194
VL - 647
IS - 22
SP - 2080
EP - 2087
PB - Weinheim-VCH GmbH
AN - OPUS4-53532
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalchuk, Adam
A1 - Rudic, S.
A1 - Pulham, C.
A1 - Morrison, C.
T1 - Predicting the impact sensitivity of a polymorphic high explosive: the curious case of FOX-7
N2 - The impact sensitivity (IS) of FOX-7 polymorphs is predicted by phonon up-pumping to decrease as layers of FOX-7 molecules flatten. Experimental validation proved anomalous owing to a phase transition during testing, raising questions regarding Impact sensitivity measurement and highlighting the need for models to predict IS of polymorphic energetic materials.
KW - Energetic materials
KW - Density functional theory
KW - Inelastic Neutron Scattering Spectroscopy
KW - Impact Sensitivity
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-535558
DO - https://doi.org/10.1039/d1cc03906g
SN - 1364-548X
VL - 57
IS - 85
SP - 11213
EP - 11216
PB - Royal Society of Chemistry
AN - OPUS4-53555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Loges, A.
A1 - Scholz, G.
A1 - de Sousa Amadeu, Nader
A1 - Jingjing, S.
A1 - Emmerling, Franziska
A1 - John, T.
A1 - Paulus, B.
A1 - Braun, T.
T1 - Studies on the local structure of the F/OH site in topaz by magic angle spinning nuclear magnetic resonance and Raman spectroscopy
N2 - he mutual influence of F and OH groups in neighboring sites in topaz (Al2SiO4(F,OH)2) was investigated using magic angle spinning nuclear magnetic resonance (MAS NMR) and Raman spectroscopy. The splitting of 19F and 1H NMR signals, as well as the OH Raman band, provides evidence for hydrogen bond formation within the crystal structure. Depending on whether a given OH group has another OH group or fluoride as its neighbor, two different hydrogen bond constellations may form: either OH···O···HO or F···H···O. The proton accepting oxygen was determined to be part of the SiO4 tetrahedron using 29Si MAS NMR. Comparison of the MAS NMR data between an OH-bearing and an OH-free topaz sample confirms that the 19F signal at −130 ppm stems from F− ions that take part in H···F bonds with a distance of ∼ 2.4 Å, whereas the main signal at −135 ppm belongs to fluoride ions with no immediate OH group neighbors. The Raman OH sub-band at 3644 cm−1 stems from OH groups neighboring other OH groups, whereas the sub-band at 3650 cm−1 stems from OH groups with fluoride neighbors, which are affected by H···F bridging. The integrated intensities of these two sub-bands do not conform to the expected ratios based on probabilistic calculations from the total OH concentration. This can be explained by a difference in the polarizability of the OH bond between the different hydrogen bond constellations or partial order or unmixing of F and OH, or a combination of both. This has implications for the quantitative interpretation of Raman data on OH bonds in general and their potential use as a probe for structural (dis-)order. No indication of tetrahedrally coordinated Al was found with 27Al MAS NMR, suggesting that the investigated samples likely have nearly ideal Al/Si ratios, making them potentially useful as high-density electron microprobe reference materials for Al and Si, as well as for F.
KW - Topas
KW - NMR
KW - XRD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561863
DO - https://doi.org/10.5194/ejm-34-507-2022
SN - 1617-4011
VL - 34
IS - 5
SP - 507
EP - 521
PB - Copernicus Publications
CY - Göttingen
AN - OPUS4-56186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mazzeo, P. P.
A1 - Prencipe, M.
A1 - Feiler, Torvid
A1 - Emmerling, Franziska
A1 - Bacchi, A.
T1 - On the mechanism of cocrystal mechanochemical reaction via low melting eutectic: A time-resolved in situ monitoring investigation
N2 - Mechanochemistry has become a sustainable and attractive cost-effective synthetic technique, largely used within the frame of crystal engineering. Cocrystals, namely, crystalline compounds made of different chemical entities within the same crystal structure, are typically synthesized in bulk via mechanochemistry; however, whereas the macroscopic aspects of grinding are becoming clear, the fundamental principles that underlie mechanochemical cocrystallization at the microscopic level remain poorly understood. Time-resolved in situ (TRIS) monitoring approaches have opened the door to exceptional detail regarding mechanochemical reactions. We here report a clear example of cocrystallization between two solid coformers that proceeds through the formation of a metastable low melting binary eutectic phase. The overall cocrystallization process has been monitored by time-resolved in situ (TRIS) synchrotron X-ray powder diffraction with a customized ball milling setup, currently available at μ Spot beamline at BESSY-II, Helmholtz-Zentrum Berlin. The binary system and the low melting eutectic phase were further characterized via DSC, HSM, and VT-XRPD.
KW - Mechanochemistry
KW - In situ
KW - Cocrystal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552977
DO - https://doi.org/10.1021/acs.cgd.2c00262
SN - 1528-7505
VL - 22
IS - 7
SP - 4260
EP - 4267
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-55297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pakrashy, S.
A1 - Mandal, P. K.
A1 - Goswami, J. N.
A1 - Dey, S. K.
A1 - Choudhury, S. M.
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
A1 - Alasmary, F. A.
A1 - Dolai, M.
T1 - Bioinformatics and Network Pharmacology of the First Crystal Structured Clerodin: Anticancer and Antioxidant Potential against Human Breast Carcinoma Cell
N2 - Clerodin was isolated from the medicinal plant Clerodendrum infortunatum, and CSD search showed the first crystal structure of clerodin by a single-crystal X-ray diffraction study. We checked its binding potential with target proteins by docking and conducted network pharmacology analysis, ADMET analysis, in silico pathway analysis, normal mode analysis (NMA), and cytotoxic activity studies to evaluate clerodin as a potential anticancer agent. The cell viability studies of clerodin on the human breast carcinoma cell line (MCF-7) showed toxicity on MCF-7 cells but no toxicity toward normal human lymphocyte cells (HLCs). The anticancer mechanism of clerodin was validated by its enhanced capacity to produce intracellular reactive oxygen species (ROS) and to lower the reduced glutathione content in MCF-7 cells.
KW - Anticancer
KW - Clerodin
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567600
DO - https://doi.org/10.1021/acsomega.2c07173
SN - 2470-1343
VL - 7
IS - 51
SP - 48572
EP - 48582
PB - ACS Publ.
CY - Washington, DC
AN - OPUS4-56760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abusafia, A.
A1 - Scheid, C.
A1 - Meurer, Maren
A1 - Altmann, Korinna
A1 - Dittmer, U.
A1 - Steinmetz, H.
T1 - Microplastic sampling strategies in urban drainage systems for quantification of urban emissions based on transport pathways
N2 - Tracking waterborne microplastic (MP) in urban areas is a challenging task because of the various sources and transport pathways involved. Since MP occurs in low concentrations in most wastewater and stormwater streams, large sample volumes need to be captured, prepared, and carefully analyzed. The recent research in urban areas focused mainly on MP emissions at wastewater treatment plants (WWTPs), as obvious entry points into receiving waters. However, important transport pathways under wet-weather conditions are yet not been investigated thoroughly. In addition, the lack of comprehensive and comparable sampling strategies complicated the attempts for a deeper understanding of occurrence and sources. The goal of this paper is to (i) introduce and describe sampling strategies for MP at different locations in a municipal catchment area under dry and wet-weather conditions, (ii) quantify MP emissions from the entire catchment and two other smaller ones within the bigger catchment, and (iii) compare the emissions under dry and wet-weather conditions. WWTP has a high removal rate of MP (>96%), with an estimated emission rate of 189 kg/a or 0.94 g/[population equivalents (PEQ · a)], and polyethylene (PE) as the most abundant MP. The specific dry-weather emissions at a subcatchment were ≈30 g/(PEQ · a) higher than in the influent of WWTP with 23 g/(PEQ · a). Specific wet-weather emissions from large sub-catchment with higher traffic and population densities were 1952 g/(ha · a) higher than the emissions from smaller catchment (796 g/[ha · a]) with less population and traffic. The results suggest that wet-weather transport pathways are likely responsible for 2–4 times more MP emissions into receiving waters compared to dry-weather ones due to tire abrasion entered from streets through gullies. However, more investigations of wet-weather MP need to be carried out considering additional catchment attributes and storm event characteristics.
KW - Combined sewer system
KW - Large volume samplers
KW - Microplastic pollution
KW - Separate sewer system
KW - Stormwater retention tank
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568271
DO - https://doi.org/10.1002/appl.202200056
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, S.
A1 - Horstmann, J.
A1 - Altmann, Korinna
A1 - Braun, U.
A1 - Hagendorf, C.
T1 - A reference methodology for microplastic particle size distribution analysis: Sampling, filtration, and detection by optical microscopy and image processing
N2 - Microplastic (MP) contamination in natural water circulation is a concern for environmental issues and human health. Various types of polymer materials have been identified and were detected in MP analytic test procedures. Beyond MP polymer type, particle size and form play a major role in water analysis due to possible negative toxicologic effects on flora and fauna. However, the correct quantitative measurement of MP size distribution over several orders of magnitude is strongly influenced by sample preparation, filtration materials and processes, and microanalytical techniques, as well as data acquisition and analysis. In this paper, a reference methodology is presented aiming at an improved quantitative analysis of MP particles. An MP analysis workflow is demonstrated including all steps from reference materials to sample preparation, filtration handling, and MP particle size distribution analysis. Background-corrected particle size distributions (1–1000 µm) have been determined for defined polyethylene (PE) and polyethylene terephthalate (PET) reference samples. Microscopically measured particle numbers and errors have been cross-checked with the total initial mass. In particular, defined reference MP samples (PE, PET) are initially characterized and applied to filtration experiments. Optical microscopy imaging on full-area Si filters with subsequent image analysis algorithms is used for statistical particle size distribution analysis. To quantify the effects of handling and filtration, several blind tests with distilled water are carried out to determine the particle background for data evaluation. Particle size distributions of PE and PET reference samples are qualitatively and quantitatively reproduced with respect to symmetry, and maximum and cut-off diameter of the distribution. It is shown that especially MP particles with a radius of >50 µm can be detected and retrieved with high reliability. For particle sizes <50 µm, a significant interference with background contamination is observed. Data from blank samples allows a correction of background contaminations. Furthermore, for enhanced sampling statistics, the recovery of the initial amount of MP will be qualitatively shown. The results are intended as an initial benchmark for MP analytics quality. This quality is based on statistical MP particle distributions and covers the complete analytic workflow starting from sample preparation to filtration and detection. Microscopic particle analysis provides an important supplement for the evaluation of established spectroscopic methods such as Fourier-transform infrared spectroscopy or Raman spectroscopy.
KW - Drinking water
KW - Filtration
KW - Microplastics detection
KW - Quality control
KW - Statistical particle distribution
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567625
DO - https://doi.org/10.1002/appl.202200055
SN - 2702-4288
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56762
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rautenberg, Max
A1 - Bhattacharya, Biswajit
A1 - Witt, Julia
A1 - Jain, Mohit
A1 - Emmerling, Franziska
T1 - In situ time-resolved monitoring of mixed-ligand metal–organic framework mechanosynthesis
N2 - The mechanism of mixed-ligand metal–organic framework (MOF) formation, and the possible role of intermediate single-ligand metal complexes during mechanosynthesis, have not been explored yet. For the first time, we report here in situ real-time monitoring of the mechanochemical formation mechanism of mixed-ligand MOFs. Our results show that binary phases can act as intermediates or competing products in one-pot and stepwise synthesis.
KW - Mechanochemistry
KW - Metal-organic-frameworks
KW - In situ X-ray diffraction
KW - Mixed-ligand MOFs
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558167
DO - https://doi.org/10.1039/D2CE00803C
SP - 1
EP - 4
PB - Royal Society of Chemistry
AN - OPUS4-55816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emmerling, Franziska
A1 - Hoch, C.
T1 - Laudatio Prof. Dr.-Ing. Caroline Röhr
N2 - It is a laudatio on the ocations of Prof. Dr.-Ing. Caroline Röhrs 60th birthday.
KW - Metal-oxides
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561877
DO - https://doi.org/10.1002/zaac.202200159
SN - 0044-2313
VL - 648
IS - 10
SP - 1
EP - 2
PB - John Wiley & Sons, Ltd
AN - OPUS4-56187
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kadri, Lena
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Tajber, Lidia
T1 - Mechanochemical comparison of ball milling processes for levofloxacin amorphous polymeric systems
N2 - This study aimed to investigate the amorphization capabilities of levofloxacin hemihydrate (LVXh), a fluoroquinolone drug, using a polymer excipient, Eudragit® L100 (EL100). Ball milling (BMing) was chosen as the manufacturing process and multiple mill types were utilized for comparison purposes. The product outcomes of each mill were analyzed in detail. The solid-state of the samples produced was comprehensively characterized by Powder X-ray Diffraction (PXRD), In-situ PXRD, Differential Scanning Calorimetry (DSC), Solid-State Fourier Transform Infrared Spectroscopy (FT-IR), and Dynamic Vapor Sorption (DVS). The crystallographic planes of LVXh were investigated by in-situ PXRD to disclose the presence or absence of weak crystallographic plane(s). The mechanism of LVXh:EL100 system formation was discovered as a two-step process, first involving amorphization of LVXh followed by an interaction with EL100, rather than as an instantaneous process. DVS studies of LVXh:EL100 samples showed different stability properties depending on the mill used and % LVXh present. Overall, a more sustainable approach for achieving full amorphization of the fluoroquinolone drug, LVXh, was accomplished, and advancements to the fast-growing world of pharmaceutical mechano- and tribo-chemistry were made.
KW - Levofloxacin
KW - Eudragit® L100
KW - Mechanochemistry
KW - Phase transformation
KW - In situ monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611129
DO - https://doi.org/10.1016/j.ijpharm.2024.124652
SN - 0378-5173
VL - 665
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-61112
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Baláž, Matej
A1 - Birinci, Mustafa
A1 - Şentürk, Kader
A1 - Achimovičová, Marcela
A1 - Baláž, Peter
A1 - Tampubolon, Imelda Octa
A1 - Stolar, Tomislav
A1 - Bienert, Ralf
A1 - Emmerling, Franziska
A1 - Erdemoğlu, Sema
A1 - Sis, Hikmet
A1 - Erdemoğlu, Murat
T1 - Utilizing Taguchi method and in situ X-ray powder diffraction monitoring to determine the influence of mechanical activation conditions on the physico-chemical properties and Al leachability of K-feldspar
N2 - K-feldspar represents an important natural resource of potassium and aluminum. Within the framework of this study, the K-feldspar was mechanically activated in a planetary ball mill under different conditions planned according to 43 Taguchi orthogonal array experimental design. As outputs, specific surface area (SBET), median particle size (d50), amorphization degree of mineral phases , and Al recovery were used. It was found that the initial d50 value of 293 μm could be reduced to 6.7 μm and the SBET value of 4.7 m2/g could be increased up to 32.5 m2/g upon milling. Both microcline KAl3SiO8, and albite NaAl3SiO8 could be almost completely amorphized, whereas quartz SiO2 still maintained some crystallinity even under the most intensive conditions. Increasing SBET and decreasing the d50 values did not lead to a significant improvement in Al leach recovery, whereas a clear relationship between the amorphization of microcline and the recovered aluminum was found. Analysis of Variance (ANOVA) showed that increasing ball-to-powder ratio is the most beneficial for the improvement in Al recovery. In situ powder X-ray diffraction monitoring performed in an oscillation ball mill under synchrotron irradiation has shown very rapid amorphization of microcline phase at the beginning. However, amorphization of microcline was only partial after two hours of the treatment in this mill, apart from almost complete process in the planetary ball mill. In the end, regressions for the calculation of Al recovery by knowing the values of input parameters were calculated. In general, by just using mechanical activation without the subsequent roasting process that is commonly used to boost metal recoveries, it was possible to quantitatively recover aluminum from K-feldspar.
KW - Mechanochemistry
KW - Mechanical activation
KW - Design of experiments
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611059
DO - https://doi.org/10.1016/j.jmrt.2024.08.156
SN - 2238-7854
VL - 32
SP - 3886
EP - 3895
PB - Elsevier B.V.
AN - OPUS4-61105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cakir, Cafer Tufan
A1 - Bogoclu, Can
A1 - Emmerling, Franziska
A1 - Streli, Christina
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
T1 - Machine learning for efficient grazing-exit x-ray absorption near edge structure spectroscopy analysis: Bayesian optimization approach
N2 - In materials science, traditional techniques for analyzing layered structures are essential for obtaining information about local structure, electronic properties and chemical states. While valuable, these methods often require high vacuum environments and have limited depth profiling capabilities. The grazing exit x-ray absorption near-edge structure (GE-XANES) technique addresses these limitations by providing depth-resolved insight at ambient conditions, facilitating in situ material analysis without special sample preparation. However, GE-XANES is limited by long data acquisition times, which hinders its practicality for various applications. To overcome this, we have incorporated Bayesian optimization (BO) into the GE-XANES data acquisition process. This innovative approach potentially reduces measurement time by a factor of 50. We have used a standard GE-XANES experiment, which serve as reference, to validate the effectiveness and accuracy of the BO-informed experimental setup. Our results show that this optimized approach maintains data quality while significantly improving efficiency, making GE-XANES more accessible to a wider range of materials science applications.
KW - Machine Learning
KW - GE-XANES
KW - Bayesian Optimization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603955
DO - https://doi.org/10.1088/2632-2153/ad4253
VL - 5
IS - 2
SP - 1
EP - 12
PB - IOP Publishing
AN - OPUS4-60395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmar, Stefan
A1 - Ruhl, Aki S.
A1 - Altmann, Korinna
A1 - Jekel, Martin
T1 - Settling Velocities of Small Microplastic Fragments and Fibers
N2 - There is only sparse empirical data on the settling velocity of small, non-buoyant microplastics thus far, although it is an important parameter governing their vertical transport within aquatic environments. This study reports the settling velocities of 4031 exemplary microplastic particles. Focusing on the environmentally most prevalent particle shapes, irregular microplastic fragments of four different polymer types (9–289 µm) as well as five discrete length fractions (50–600 µm) of common nylon and polyester fibers were investigated, respectively. All settling experiments were carried out in quiescent water using a specialized optical imaging setup. The method has been previously validated in order to minimize disruptive factors, e.g. thermal convection or particle interactions, and thus enable the precise measurements of the velocities of individual microplastic particles (0.003–9.094 mm/s). Based on the obtained data, ten existing models for predicting a particle’s terminal settling velocity were assessed. It is concluded that models, which were specifically deduced from empirical data on larger microplastics, fail to provide accurate predictions for small microplastics. Instead, a different approach is highlighted as a viable option for computing settling velocities across the microplastics continuum in terms of size, density and shape.
KW - Microplastics
KW - Microplastic fibers
KW - Settling velocity
KW - Sinking velocity
KW - Sedimentation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597455
DO - https://doi.org/10.1021/acs.est.3c09602
SN - 0013-936X
VL - 58
IS - 14
SP - 6359
EP - 6369
PB - American Chemical Society (ACS)
AN - OPUS4-59745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Coburger, Peter
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Emmerling, Franziska
A1 - Abbenseth, Josh
T1 - Combining geometric constraint and redox non-innocence within an ambiphilic PBiP pincer ligand
N2 - The first pincer ligand featuring a strictly T-shaped pnictogen donor moiety was synthesised. The PBiP ligand's redox activity facilitates unprecedented ambiphilic bonding of the Bi centre with transition metals through the Bi(6p) orbital.
KW - EXAFS
KW - Pincer Ligand
KW - Group 15 metals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611113
DO - https://doi.org/10.1039/D4SC00197D
SN - 2041-6520
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-61111
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Goldammer, Ole
A1 - Bader, Julia
A1 - Emmerling, Franziska
A1 - Riedel, Sebastian
T1 - Introducing AFS ([Al(SO3F)3]x) – a thermally stable, readily available, and catalytically active solid Lewis superacid
N2 - This paper introduces the thermally stable, solid Lewis superacid aluminium tris(fluorosulfate) (AFS), that is easy-to-synthesize from commercially available starting materials. Its applicability, e.g. in catalytic C–F bond activations, is shown.
KW - Lewis Acid
KW - C-F activation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601001
DO - https://doi.org/10.1039/D4SC01753F
SN - 2041-6520
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Senges, Gene
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Lindič, Tilen
A1 - Gully, Tyler A.
A1 - Winter, Marlon
A1 - Radtke, Martin
A1 - Röder, Bettina
A1 - Steinhauer, Simon
A1 - Paulus, Beate
A1 - Emmerling, Franziska
A1 - Riedel, Sebastian
T1 - Unravelling highly oxidized nickel centers in the anodic black film formed during the Simons process by in situ X-ray absorption near edge structure spectroscopy
N2 - The electrofluorination after Simons has been used for the last century to produce everyday life materials. An in situ XANES investigation of the controversially debated black film apparent in the Simons process revealed high-valent nickel centers.
KW - Synchrotron
KW - BAMline
KW - XANES
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608366
DO - https://doi.org/10.1039/d3sc06081k
SN - 2041-6520
VL - 15
IS - 12
SP - 4504
EP - 4509
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Das, Prasenjit
A1 - Chakraborty, Gouri
A1 - Friese, Nico
A1 - Roeser, Jérôme
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Schmidt, Johannes
A1 - Thomas, Arne
T1 - Heteropolyaromatic Covalent Organic Frameworks via One-Pot Multicomponent Reactions
N2 - Multicomponent reactions (MCRs) offer a platform to create different chemical structures and linkages for highly stable covalent organic frameworks (COFs). As an illustrative example, the multicomponent Povarov reaction generates 2,4-phenylquinoline from aldehydes and amines in the presence of electron-rich alkenes. In this study, we introduce a new domino reaction to generate unprecedented 2,3-phenylquinoline COFs in the presence of epoxystyrene. This work thus presents, for the first time, structural isomeric COFs produced by multicomponent domino and Povarov reactions. Furthermore, 2,3-phenylquinolines can undergo a Scholl reaction to form extended aromatic linkages. With this approach, we synthesize two thermally and chemically stable MCR-COFs and two heteropolyaromatic COFs using both domino and in situ domino and Scholl reactions. The structure and properties of these COFs are compared with the corresponding 2,4-phenylquinoline-linked COF and imine-COF, and their activity toward benzene and cyclohexane sorption and separation is investigated. The position of the pendant phenyl groups within the COF pore plays a crucial role in facilitating the industrially important sorption and separation of benzene over cyclohexane. This study opens a new avenue to construct heteropolyaromatic COFs via MCR reactions.
KW - COF
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604038
DO - https://doi.org/10.1021/jacs.4c02551
SP - 1
EP - 9
PB - American Chemical Society (ACS)
AN - OPUS4-60403
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiesner, Yosri
A1 - Hoffmann, Thomas
A1 - Range, David
A1 - Altmann, Korinna
T1 - Microplastics in sediments of the river Rhine—A workflow for preparation and analysis of sediment samples from aquatic river systems for monitoring purposes
N2 - AbstractMicroplastics (MP) can be detected in all environmental systems. Marine and terrestrial aquatic systems, especially the transported suspended solids, have often been the focus of scientific investigations in the past. Sediments of aquatic river systems, on the other hand, were often ignored due to the time‐consuming sample preparation and analysis procedures. Spectroscopic measurement methods counting particle numbers are hardly suitable as detection methods, because there are plenty of natural particles next to a small number of MP particles. Integral methods, such as thermoanalytical methods are determining the particle mass independently of the inorganic components.In this study, a workflow for sample preparation via density separation and subsequent analysis by thermal extraction desorption‐gas chromatography/mass spectrometry is presented, which leads to representative and homogeneous samples and allows fast and robust MP mass content measurements suitable for routine analysis. Polymers were identified and quantified in all samples. Polyethylene and styrene‐butadiene rubber are the dominant polymers, besides polypropylene and polystyrene. Overall, total polymer masses between 1.18 and 337.0 µg/g could be determined. Highest MP concentrations in riverbed sediment are found in sites characterized by low flow velocities in harbors and reservoirs, while MP concentrations in sandy/gravelly bed sediments with higher flow velocities are small.
KW - Microplastics
KW - Density separation
KW - TED-GC/MS
KW - NaI
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597335
DO - https://doi.org/10.1002/appl.202200125
VL - 3
IS - 2
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Janina
A1 - Kaufmann, Jan Ole
A1 - Weller, Michael G.
T1 - Simple Determination of Affinity Constants of Antibodies by Competitive Immunoassays
N2 - The affinity constant, also known as the equilibrium constant, binding constant, equilibrium association constant, or the reciprocal value, the equilibrium dissociation constant (Kd), can be considered as one of the most important characteristics for any antibody–antigen pair. Many methods based on different technologies have been proposed and used to determine this value. However, since a very large number of publications and commercial datasheets do not include this information, significant obstacles in performing such measurements seem to exist. In other cases where such data are reported, the results have often proved to be unreliable. This situation may indicate that most of the technologies available today require a high level of expertise and effort that does not seem to be available in many laboratories. In this paper, we present a simple approach based on standard immunoassay technology that is easy and quick to perform. It relies on the effect that the molar IC50 approaches the Kd value in the case of infinitely small concentrations of the reagents. A two-dimensional dilution of the reagents leads to an asymptotic convergence to Kd. The approach has some similarity to the well-known checkerboard titration used for the optimization of immunoassays. A well-known antibody against the FLAG peptide, clone M2, was used as a model system and the results were compared with other methods. This approach could be used in any case where a competitive assay is available or can be developed. The determination of an affinity constant should belong to the crucial parameters in any quality control of antibody-related products and assays and should be mandatory in papers using immunochemical protocols.
N2 - Die Affinitätskonstante, auch bekannt als Gleichgewichtskonstante, Bindungskonstante, Gleichgewichtsassoziationskonstante oder der reziproke Wert, die Gleichgewichtsdissoziationskonstante (Kd), kann als eine der wichtigsten Eigenschaften für jedes Antikörper-Antigen-Paar angesehen werden. Zur Bestimmung dieses Wertes wurden zahlreiche Methoden auf der Grundlage verschiedener Technologien vorgeschlagen und verwendet. Da jedoch eine sehr große Anzahl von Veröffentlichungen und kommerziellen Datenblätter diese Information nicht enthalten, scheint es erhebliche Hindernisse bei der Durchführung solcher Messungen zu geben. In anderen Fällen, in denen solche Daten angegeben werden, haben sich die Ergebnisse häufig als unzuverlässig erwiesen. Diese Situation könnte darauf hindeuten, dass die meisten der heute verfügbaren Technologien ein hohes Maß an Fachwissen und Aufwand erfordern, das in vielen Labors nicht vorhanden zu sein scheint. In diesem Beitrag stellen wir einen einfachen Ansatz vor, der auf der Standard-Immunoassay-Technologie basiert und einfach und schnell durchführbar ist. Er beruht auf dem Effekt, dass sich der molare IC50 bei unendlich kleinen Reagenz-Konzentrationen dem Kd-Wert annähert. Eine zweidimensionale Verdünnung der Reagenzien führt zu einer asymptotischen Konvergenz zu Kd. Der Ansatz hat eine gewisse Ähnlichkeit mit der bekannten Checkerboard-Titration, die zur Optimierung von Immunoassays verwendet wird. Ein bekannter Antikörper gegen das FLAG-Peptid, Klon M2, wurde als Modellsystem verwendet, und die Ergebnisse wurden mit anderen Methoden verglichen. Dieser Ansatz kann überall dort angewendet werden, wo ein kompetitiver Assay verfügbar ist oder entwickelt werden kann. Die Bestimmung einer Affinitätskonstante sollte zu den entscheidenden Parametern bei der Qualitätskontrolle von Antikörperprodukten und -assays gehören und in Arbeiten, die immunchemische Protokolle verwenden, obligatorisch sein.
KW - ELISA
KW - Competitive immunoassay
KW - IC50
KW - Test midpoint
KW - Point of inflection
KW - Equilibrium constant
KW - Dissociation constant
KW - Binding strength
KW - Antibody antigen complex
KW - Bio-interaction
KW - SPR
KW - Surface-plasmon resonance
KW - FLAG peptide
KW - Clone M2
KW - Antibody quality
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605607
DO - https://doi.org/10.3390/mps7030049
SN - 2409-9279
VL - 7
IS - 3
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-60560
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Béalu, Zoé
A1 - Walther, Johanna
A1 - Abusafia, Attaallah
A1 - Altmann, Korinna
A1 - Meurer, Maren
A1 - Gretzschel, Oliver
A1 - Schäfer, Michael
A1 - Steinmetz, Heidrun
T1 - Removal of Organic Micropollutants and Microplastics via Ozonation Followed by Granular Activated Carbon Filtration
N2 - Discharge from Wastewater Treatment Plants (WWTPs) can result in the emission of organic micropollutants (OMPs) and microplastics (MPs) into the aquatic environment. To prevent this harmful release, a pilot plant consisting of an ozonation followed by a granular activated carbon (GAC) filter was operated at a WWTP in Germany, and its side-effects on the concentrations of nitrogen (N) and phosphorous (P) compounds were measured. Over 80% of OMPs and transformation products were removed during the operating time (around 6000 bed volumes) no matter the ozone dose (from around 0.1 to 0.5 mgO3/mgDOC), except for Diatrizoic acid, whose breakthrough appeared at 3500 BV. Formation of the oxidation by-product, NDMA, increased with higher ozone doses, but the concentration remained below 100 ng/L. Bromate was formed at a higher ozone dose (0.4 mgO3/mgDOC) but at a low concentration—below 10 µg/L. The MP particles detected in the inflow (PE, SBR, PP, and PS) were effectively eliminated to a high degree, with a removal rate of at least 92%. Carbon parameters (COD, DOC, and SAC254) were removed further by the pilot plant, but to different extents. As expected, nitrate was formed during ozonation, while nitrite’s concentration decreased. Further, nitrite decreased and nitrate increased within the GAC filter, while ammonium was eliminated by at least 90%. Total P concentration decreased after the pilot, but the concentration of PO4-P increased.
KW - Microplastics
KW - TED-GC/MS
KW - Granular Activated Carbon Filtration
KW - Removal of Organic Micropollutants
KW - Wastewater treatment plant
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615209
DO - https://doi.org/10.3390/environments11110241
VL - 11
IS - 11
SP - 1
EP - 38
PB - MDPI AG
AN - OPUS4-61520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fadda, Marta
A1 - Sacco, Alessio
A1 - Altmann, Korinna
A1 - Ciornii, Dmitri
A1 - Milczewski, Frank
A1 - Bañares, Miguel A.
A1 - Portela, Raquel
A1 - Giovannozzi, Andrea Mario
A1 - Rossi, Andrea Mario
T1 - Tracking nanoplastics in drinking water: a new frontier with the combination of dielectrophoresis and Raman spectroscopy
N2 - Detection of micro- (MPs) and nanoplastics (NPs) in food and environmental matrices has been gaining relevance due to their potential toxicological effects on human health. While MPs have been detected in a wide range of complex matrices, suitable methods for the characterization and chemical identification of NPs are still lacking, primarily due to significant methodological challenges associated with their nano-specific physiochemical properties, including size distribution (1 nm – 1 µm), dynamic surface chemical changes, and carbon-based composition, which complicate their detection compared to engineered nanomaterials. To overcome the traditional limitations of spectroscopic techniques in terms of spatial resolution and sensitivity at the sub-micrometer level, a novel label-free methodology is presented for specifically identifying the chemical composition of NPs directly in suspension by combining Raman spectroscopy with dielectrophoresis (DEP). Using a custom-built device, small volumes of NPs are injected into a dielectrophoretic cell and locally trapped by DEP forces to fill the Raman confocal volume, facilitating their detection and identification, and providing high signal-to-noise ratio Raman spectra for more reliable analysis. This approach was successfully applied to both Milli-Q water and a commercial brand of drinking water, enabling the rapid identification of various types of NPs with different sizes and polymer compositions at concentrations as low as 20 µg/mL. These included certified reference polystyrene beads ranging from 800 to 60 nm in diameter, as well as polydisperse NPs, more representative of real samples in terms of size distribution and polymer type, such as polyethylene (450 nm), polypropylene (180 nm), and polyethylene terephthalate (100 nm). Moreover, the chemical fingerprint of each NPs was thoroughly investigated and compared with the corresponding bulk polymers, highlighting possible changes in the Raman bands due to surface oxidation or nanometer-scale effect. Therefore, this innovative method can be considered a valuable approach for addressing gaps in the detection and identification of NPs, as well as for monitoring their dynamic phisiochemical changes in real matrices.
KW - Nanoplastics
KW - Water contaminants
KW - Raman microspectroscopy
KW - Dielectrophoresis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633658
DO - https://doi.org/10.1186/s43591-025-00131-y
SN - 2662-4966
VL - 5
IS - 1
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-63365
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ciornii, Dmitri
A1 - Hodoroaba, Vasile-Dan
A1 - Wachtendorf, Volker
A1 - Fengler, Petra
A1 - Altmann, Korinna
T1 - Interlaboratory Comparison Reveals State of the Art in Microplastic Detection and Quantification Methods
N2 - In this study, we investigate the current accuracy of widely used microplastic (MP) detection methods through an interlaboratory comparison (ILC) involving ISO-approved techniques. The ILC was organized under the prestandardization platform of VAMAS (Versailles Project on Advanced Materials and Standards) and gathered a large number (84) of analytical laboratories across the globe. The aim of this ILC was (i) to test and to compare two thermo-analytical and three spectroscopical methods with respect to their suitability to identify and quantify microplastics in a water-soluble matrix and (ii) to test the suitability of the microplastic test materials to be used in ILCs. Two reference materials (RMs), polyethylene terephthalate (PET) and polyethylene (PE) as powders with rough size ranges between 10 and 200 μm, were used to press tablets for the ILC. The following parameters had to be assessed: polymer identity, mass fraction, particle number concentration, and particle size distribution. The reproducibility, SR, in thermo-analytical experiments ranged from 62%−117% (for PE) and 45.9%−62% (for PET). In spectroscopical experiments, the SR varied between 121% and 129% (for PE) and 64% and 70% (for PET). Tablet dissolution turned out to be a very challenging step and should be optimized. Based on the knowledge gained, development of guidance for improved tablet filtration is in progress. Further, in this study, we discuss the main sources of uncertainties that need to be considered and minimized for preparation of standardized protocols for future measurements with higher accuracy.
KW - Microplastics
KW - Interlaboratory comparison
KW - PlasticsFatE
KW - PET
KW - PE
KW - Reference materials
KW - VAMAS
KW - Thermo-analytical methods
KW - Spectroscopical methods
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630462
DO - https://doi.org/10.1021/acs.analchem.4c05403
SN - 1520-6882
VL - 97
SP - 8719
EP - 8728
PB - ACS Publications
AN - OPUS4-63046
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bartczak, Dorota
A1 - Sikora, Aneta
A1 - Goenaga-Infante, Heidi
A1 - Altmann, Korinna
A1 - Drexel, Roland
A1 - Meier, Florian
A1 - Alasonati, Enrica
A1 - Lelong, Marc
A1 - Cado, Florence
A1 - Chivas-Joly, Carine
A1 - Fadda, Marta
A1 - Sacco, Alessio
A1 - Rossi, Andrea Mario
A1 - Pröfrock, Daniel
A1 - Wippermann, Dominik
A1 - Barbero, Francesco
A1 - Fenoglio, Ivana
A1 - Booth, Andy M.
A1 - Sørensen, Lisbet
A1 - Igartua, Amaia
A1 - Wouters, Charlotte
A1 - Mast, Jan
A1 - Barbaresi, Marta
A1 - Rossi, Francesca
A1 - Piergiovanni, Maurizio
A1 - Mattarozzi, Monica
A1 - Careri, Maria
A1 - Caebergs, Thierry
A1 - Piette, Anne-Sophie
A1 - Parot, Jeremie
A1 - Giovannozzi, Andrea Mario
T1 - Multiparameter characterisation of a nano-polypropylene representative test material with fractionation, light scattering, high-resolution microscopy, spectroscopy, and spectrometry methods
N2 - Reference and quality control materials with comparable physicochemical properties to nanoplastic contaminants present in environmental and food nanoplastics are currently lacking. Here we report a nanoplastic polypropylene material prepared using a top-down approach involving mechanical fragmentation of larger plastics. The material was found to be homogeneous and stable in suspension and has been characterised for average particle size, size distribution range, particle number concentration, polypropylene mass fraction and inorganic impurity Content using a wide range of analytical methods, including AF4, cFFF, PTA, (MA)DLS, MALS, SEM, AFM, TEM, STEM, EDS,Raman, ICP-MS and pyGC-MS. The material was found to have a broad size distribution, ranging from 50 nm to over 200 nm, with the average particle size value dependent on the technique used to determine it. Particle number concentration ranged from 1.7–2.4 × 1010 g−1 , according to PTA. Spectroscopy techniques confirmed that the material was polypropylene, with evidence of aging due to an increased level of oxidation. The measured mass fraction was found to depend on the marker used and ranged between 3 and 5 μg g−1 . Inorganic impurities such as Si, Al, Mg, K, Na, S, Fe, Cl and Ca were also identified at ng g−1 levels. Comparability and complementarity across the measurement methods and techniques is also discussed.
KW - Polypropylene
KW - Nanoplastics
KW - Analytics
KW - Reference material
KW - Scattering methods
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654680
DO - https://doi.org/10.1039/D5EN00917K
SN - 2051-8153
SP - 1
EP - 15
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65468
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kittner, Maria
A1 - Coesfeld, Bianca
A1 - Schlau, Sven
A1 - Werischak, Thomas
A1 - Altmann, Korinna
A1 - Kalbe, Ute
T1 - Simultaneous sampling for microplastics and environmental contaminants from artificial turf: development of a new integrated microplastics eluate lysimeter
N2 - To get a better understanding of potentially harmful contaminant emissions from soils or materials into the environment, politics demand practical and holistic sampling concepts for environmental samples such as leachates containing polycyclic aromatic hydrocarbons (PAH) or heavy metals, and hazardous particulate matter like microplastics (MP). Of particular concern are MP emissions from artificial turf sports pitches. So far, there has been only very limited data on MP mass emissions from artificial turf potentially posing a risk to the groundwater and no sampling device that allowed simultaneous sampling for dissolved and particulate contaminants. In this study, a novel integrative microplastics eluate lysimeter was developed to determine contaminant emissions from three artificial turf systems at different ageing states (fabric-new, artificially aged, real-time aged). For the accelerated ageing, all environmental simulation parameters were based on Central German conditions and simulated outdoor stress during the turf service lifespan of 15 years. MP masses from eluates were analysed using thermal extraction desorption-gas chromatography/mass spectrometry, PAH concentrations using gas chromatography/mass spectrometry and heavy metals using inductively coupled plasma-optical emission spectroscopy. Results showed that no PAH or heavy metal concentrations from the seepage water were above German legal limits for alternative granular construction materials considering soil and groundwater protection. Furthermore, it was found that only minimal MP emissions were released from new turf systems into the seepage water (< 1 mg/m2). Ageing of the artificial turf increased MP formation, especially from rubber infill and grass fibres, which are then carried into the seepage water. The highest total MP emissions over a simulated turf lifespan of 15 years were detected in two real-time aged turf systems ranging from 136.4–252.5 mg/m2. Considerably less total MP emissions were detected in accelerated aged artificial turf systems, one of which contained a synthetic rubber infill (5.4–8.0 mg/m2) and one without rubber infill (0.2–5.3 mg/m2). In summary, it was demonstrated that the newly developed MEL generated reliable and reproducible data and has thus proven itself as an integrated, straightforward and automated sampling device for simultaneous monitoring of particulate and dissolved pollutant emissions from simple soil matrices.
KW - Lysimeter
KW - Microplastics
KW - Artificial turf
KW - Thermal extraction desorption-gas chromatography/mass spectrometry
KW - TED-GC/MS
KW - Polycyclic aromatic hydrocarbons
KW - PAH
KW - Heavy metals
KW - Soil samples
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645301
DO - https://doi.org/10.1186/s12302-025-01235-1
SN - 2190-4715
VL - 37
IS - 1
SP - 1
EP - 15
PB - Springer Open
AN - OPUS4-64530
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herzel, Hannes
A1 - Grevel, K.-D.
A1 - Emmerling, Franziska
A1 - Dachs, E.
A1 - Benisek, A.
A1 - Adam, Christian
A1 - Majzlan, J.
T1 - Thermodynamic properties of calcium alkali phosphates Ca(Na,K)PO4
N2 - Calcium alkali phosphates Ca(Na,K)PO4 are main constituents of bioceramics and thermochemically produced phosphorus fertilizers because of their bioavailability. Sparse thermodynamic data are available for the endmembers CaNaPO4 and CaKPO4. In this work, the missing data were determined for the low-temperature phase modifications of the endmembers CaNaPO4 and CaKPO4 and three intermediate Ca(Na,K)PO4 compositions. Standard enthalpy of formation ranges from - 2018.3 ± 2.2 kJ mol-1 to - 2030.5 ± 2.1 kJ mol-1 and standard entropy from 137.2 ± 1.0 J mol-1 K-1 to 148.6 ± 1.0 J mol-1 K-1 from sodium endmember b-CaNaPO4 to potassium endmember b0-CaKPO4.
Thermodynamic functions are calculated up to 1400 K for endmembers and the sodium-rich intermediate phase b-Ca(Na0.93K0.07)PO4. Functions above 640 K are extrapolated because of the phase transition from low- to high-temperature phase. Impurities in the synthesized intermediate phases c-Ca(Na0.4K0.6)PO4 and c-Ca Na0.35K0.65)PO4 and one additional phase transition around 500 K impeded the determination of high-temperature thermodynamic functions. In general, data for phase transition temperatures agree with the previously reported phase diagrams.
KW - Formation enthalpy
KW - Heat capacity
KW - Phase transformation
KW - Bioceramics
KW - Phosphorus fertilizer
KW - Entropy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507640
DO - https://doi.org/10.1007/s10853-020-04615-5
VL - 55
SP - 8477
EP - 8490
PB - Springer
AN - OPUS4-50764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Steglich, P.
A1 - Rabus, D. G.
A1 - Sada, C.
A1 - Paul, Martin
A1 - Weller, Michael G.
A1 - Mai, C.
A1 - Mai, A.
T1 - Silicon Photonic Micro-Ring Resonators for Chemical and Biological Sensing: A Tutorial
N2 - Silicon photonic micro-ring resonators (MRR) developed on the silicon-on-insulator (SOI) platform, owing to their high sensitivity and small footprint, show great potential for many chemical and biological sensing applications such as label-free detection in environmental monitoring, biomedical engineering, and food analysis. In this tutorial, we provide the theoretical background and give design guidelines for SOI-based MRR as well as examples of surface functionalization procedures for label-free detection of molecules.
After introducing the advantages and perspectives of MRR, fundamentals of MRR are described in detail, followed by an introduction to the fabrication methods, which are based on a complementary metal-oxide semiconductor (CMOS) technology. Optimization of MRR for chemical and biological sensing is provided, with special emphasis on the optimization of waveguide geometry. At this point, the difference between chemical bulk sensing and label-free surface sensing is explained, and definitions like waveguide sensitivity, ring sensitivity, overall sensitivity as well as the limit of detection (LoD) of MRR are introduced. Further, we show and explain chemical bulk sensing of sodium chloride (NaCl) in water and provide a recipe for label-free surface sensing.
KW - Lab on a chip
KW - Biosensor
KW - Cmos
KW - Silanization
KW - Surface derivatization
KW - Evanescent wave
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529360
DO - https://doi.org/10.36227/techrxiv.14909901.v1
SP - 1
EP - 18
PB - IEEE
CY - Piscataway Township
AN - OPUS4-52936
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Martin
A1 - Tannenberg, Robert
A1 - Tscheuschner, Georg
A1 - Ponader, Marco
A1 - Weller, Michael G.
T1 - Cocaine detection by a laser-induced immunofluorometric biosensor
N2 - The trafficking of illegal drugs by criminal networks at borders, harbors, or airports is an increasing issue for public health as these routes ensure the main supply of illegal drugs. The prevention of drug smuggling, including the installation of scanners and other analytical devices to detect small traces of drugs within a reasonable time frame, remains a challenge. The presented immunosensor is based on a monolithic affinity column with a large excess of immobilized hapten, which traps fluorescently labeled antibodies as long as the analyte cocaine is absent. In the presence of the drug, some binding sites of the antibody will be blocked, which leads to an immediate breakthrough of the labeled protein, detectable by highly sensitive laser-induced fluorescence with the help of a Peltier-cooled complementary metal-oxide-semiconductor (CMOS) camera. Liquid handling is performed with high-precision syringe pumps and microfluidic chip-based mixing devices and flow cells. The biosensor achieved limits of detection of 7 ppt (23 pM) of cocaine with a response time of 90 s and a total assay time below 3 min. With surface wipe sampling, the biosensor was able to detect 300 pg of cocaine. This immunosensor belongs to the most sensitive and fastest detectors for cocaine and offers near-continuous analyte measurement.
KW - Online detection
KW - Security
KW - Monoclonal antibody
KW - Microfluidic mixing
KW - Microfluidics
KW - Lab-on-a-chip
KW - Monolithic column
KW - Affinity chromatography
KW - Laser-induced fluorescence
KW - LIF
KW - ELISA
KW - Wipe test
KW - Low-cost
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534487
DO - https://doi.org/10.3390/bios11090313
VL - 11
IS - 9
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-53448
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Möckel, J.
A1 - Brangsch, J.
A1 - Reimann, C.
A1 - Kaufmann, Jan Ole
A1 - Sack, I.
A1 - Mangarova, D. B.
A1 - Kader, A.
A1 - Taupitz, M.
A1 - Adams, L. C.
A1 - Keller, S.
A1 - Ludwig, A.
A1 - Hamm, B.
A1 - Botnar, R. M.
A1 - Makowski, M. R.
T1 - Assessment of Albumin ECM Accumulation and Inflammation as Novel In Vivo Diagnostic Targets for Multi-Target MR Imaging
N2 - Atherosclerosis is a progressive inflammatory vascular disease characterized by endothelial dysfunction and plaque burden. Extracellular matrix (ECM)-associated plasma proteins play an important role in disease development. Our magnetic resonance imaging (MRI) study investigates the feasibility of using two different molecular MRI probes for the simultaneous assessment of ECM-associated intraplaque albumin deposits caused by endothelial damage and progressive inflammation in atherosclerosis. Male apolipoprotein E-deficient (ApoE-/-)-mice were fed a high-fat diet (HFD) for 2 or 4 months. Another ApoE-/--group was treated with pravastatin and received a HFD for 4 months. T1- and T2*-weighted MRI was performed before and after albumin-specific MRI probe (gadofosveset) administration and a macrophage-specific contrast agent (ferumoxytol). Thereafter, laser ablation inductively coupled plasma mass spectrometry and histology were performed. With advancing atherosclerosis, albumin-based MRI signal enhancement and ferumoxytol-induced signal loss areas in T2*-weighted MRI increased. Significant correlations between contrast-to-noise-ratio (CNR) post-gadofosveset and albumin stain (R2 = 0.78, p < 0.05), and signal loss areas in T2*-weighted MRI with Perls’ Prussian blue stain (R2 = 0.83, p < 0.05) were observed. No interference of ferumoxytol with gadofosveset enhancement was detectable. Pravastatin led to decreased inflammation and intraplaque albumin. Multi-target MRI combining ferumoxytol and gadofosveset is a promising method to improve diagnosis and treatment monitoring in atherosclerosis.
KW - Magnetic resonance imaging
KW - MRI
KW - Imaging
KW - Human serum albumin
KW - Extracellular matrix
KW - Macrophages
KW - Contrast agent
KW - Atherosclerotic plaques
KW - Gadofosveset
KW - Aneurysm
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536725
DO - https://doi.org/10.3390/biology10100964
VL - 10
IS - 10
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Backes, A. T.
A1 - Reinmuth-Selzle, K.
A1 - Leifke, A. L.
A1 - Ziegler, K.
A1 - Krevert, C. S.
A1 - Tscheuschner, Georg
A1 - Lucas, K.
A1 - Weller, Michael G.
A1 - Berkemeier, T.
A1 - Pöschl, U.
A1 - Fröhlich-Nowoisky, J.
T1 - Oligomerization and Nitration of the Grass Pollen Allergen Phl p 5 by Ozone, Nitrogen Dioxide, and Peroxynitrite: Reaction Products, Kinetics, and Health Effects
N2 - The allergenic and inflammatory potential of proteins can be enhanced by chemical modification upon exposure to atmospheric or physiological oxidants. The molecular mechanisms and kinetics of such modifications, however, have not yet been fully resolved. We investigated the oligomerization and nitration of the grass pollen allergen Phl p 5 by ozone (O3), nitrogen dioxide (NO2), and peroxynitrite (ONOO–). Within several hours of exposure to atmospherically relevant concentration levels of O3 and NO2, up to 50% of Phl p 5 were converted into protein oligomers, likely by formation of dityrosine cross-links. Assuming that tyrosine residues are the preferential site of nitration, up to 10% of the 12 tyrosine residues per protein monomer were nitrated. For the reaction with peroxynitrite, the largest oligomer mass fractions (up to 50%) were found for equimolar concentrations of peroxynitrite over tyrosine residues. With excess peroxynitrite, the nitration degrees increased up to 40% whereas the oligomer mass fractions decreased to 20%. Our results suggest that protein oligomerization and nitration are competing processes, which is consistent with a two-step mechanism involving a reactive oxygen intermediate (ROI), as observed for other proteins. The modified proteins can promote pro-inflammatory cellular signaling that may contribute to chronic inflammation and allergies in response to air pollution.
KW - Protein
KW - Nitrotyrosine
KW - Dityrosine
KW - Allergy
KW - Hay fever
KW - Diesel exhaust
KW - Combustion
KW - Exhaust
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529729
DO - https://doi.org/10.3390/ijms22147616
VL - 22
IS - 14
PB - MDPI
CY - Basel
AN - OPUS4-52972
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adams, L. C.
A1 - Brangsch, J.
A1 - Reimann, C.
A1 - Kaufmann, Jan Ole
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Botnar, R. M.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Simultaneous molecular MRI of extracellular matrix collagen and inflammatory activity to predict abdominal aortic aneurysm rupture
N2 - Abdominal aortic aneurysm (AAA) is a life-threatening vascular disease with an up to 80% mortality in case of rupture. Current biomarkers fail to account for size-independent risk of rupture. By combining the information of different molecular probes, multi-target molecular MRI holds the potential to enable individual characterization of AAA. In this experimental study, we aimed to examine the feasibility of simultaneous imaging of extracellular collagen and inflammation for size-independent prediction of risk of rupture in murine AAA. The study design consisted of: (1) A outcome-based longitudinal study with imaging performed once after one week with follow-up and death as the end-point for assessment of rupture risk. (2) A week-by-week study for the characterization of AAA development with imaging after 1, 2, 3 and 4 weeks. For both studies, the animals were administered a type 1 collagen-targeted gadolinium-based probe (surrogate marker for extracellular matrix (ECM) remodeling) and an iron oxide-based probe (surrogate marker for inflammatory activity), in one imaging session. In vivo measurements of collagen and iron oxide probes showed a significant correlation with ex vivo histology (p < 0.001) and also corresponded well to inductively-coupled plasma-mass spectrometry and laser-ablation inductively-coupled plasma mass spectrometry. Combined evaluation of collagen-related ECM remodeling and inflammatory activity was the most accurate predictor for AAA rupture (sensitivity 80%, specificity 100%, area under the curve 0.85), being superior to information from the individual probes alone. Our study supports the feasibility of a simultaneous assessment of collagen-related extracellular matrix remodeling and inflammatory activity in a murine model of AAA.
KW - Atherosclerosis
KW - Specific probe
KW - Magnetic resonance imaging
KW - Gadolinium
KW - Iron oxide
KW - Ferumoxytol
KW - Inductively‑coupled mass spectrometry
KW - ICP-MS
KW - LA-ICP-MS
KW - Laser ablation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525864
UR - https://www.nature.com/articles/s41598-020-71817-x
DO - https://doi.org/10.1038/s41598-020-71817-x
VL - 10
IS - 1
SP - 15206
PB - Springer Nature Limited
CY - London, New York, Berlin, Shanghai and Tokyo
AN - OPUS4-52586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ponader, Marco
A1 - Röder, Bettina
A1 - Paul, Martin
A1 - Weller, Michael G.
T1 - Sintered glass monoliths as supports for affinity columns
N2 - A novel stationary phase for affinity separations is presented. This material is based on sintered borosilicate glass readily available as semi-finished filter plates with defined porosity and surface area. The material shows fast binding kinetics and excellent long-term stability under real application conditions due to lacking macropores and high mechanical rigidity. The glass surface can be easily modified with standard organosilane chemistry to immobilize selective binders or other molecules used for biointeraction. In this paper, the manufacturing of the columns and their respective column holders by 3D printing is shown in detail. The model system protein A/IgG was chosen as an example to examine the properties of such monolithic columns under realistic application conditions. Several specifications, such as (dynamic) IgG capacity, pressure stability, long-term performance, productivity, non-specific binding, and peak shape, are presented. It could be shown that due to the very high separation speed, 250 mg antibody per hour and column can be collected, which surpasses the productivity of most standard columns of the same size. The total IgG capacity of the shown columns is around 4 mg (5.5 mg/mL), which is sufficient for most tasks in research laboratories. The cycle time of an IgG separation can be less than 1 min. Due to the glass material’s excellent pressure resistance, these columns are compatible with standard HPLC systems. This is usually not the case with standard affinity columns, limited to manual use or application in low-pressure systems. The use of a standard HPLC system also improves the ability for automation, which enables the purification of hundreds of cell supernatants in one day. The sharp peak shape of the elution leads to an enrichment effect, which might increase the concentration of IgG by a factor of 3. The final concentration of IgG can be around 7.5 mg/mL without the need for an additional nano-filtration step. The purity of the IgG was > 95% in one step and nearly 99% with a second polishing run.
KW - Affinity Chromatography
KW - Affinity Extraction
KW - Affinity Separation
KW - Protein Purification
KW - Down Stream Processing
KW - Antibody Purification
KW - Diagnostic Antibodies
KW - Therapeutic Antibodies
KW - Automated Purification
KW - HPLC
KW - FPLC
KW - IgG determination
KW - Concentration step
KW - Monoclonal Antibodies
KW - Polyclonal Antibodies
KW - Human Plasma
KW - Glass Support
KW - Borosilicate Glass
KW - Monolith
KW - Sintered Material
KW - Additive Manufacturing
KW - Column holder
KW - Construction
KW - Open Science
KW - Citizen Science
KW - Protein A
KW - Regeneration
KW - High-Speed Separations
KW - Robustness
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527581
DO - https://doi.org/10.3390/separations8050056
SN - 2297-8739
N1 - Geburtsname von Ponader, Marco: Wilke, M. - Birth name of Ponader, Marco: Wilke, M.
VL - 8
IS - 5
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-52758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Adams, L. C.
A1 - Brangsch, J.
A1 - Reimann, C.
A1 - Kaufmann, Jan Ole
A1 - Nowak, K.
A1 - Buchholz, R.
A1 - Karst, U.
A1 - Botnar, R. M.
A1 - Hamm, B.
A1 - Makowski, M. R.
T1 - Noninvasive imaging of vascular permeability to predict the risk of rupture in abdominal aortic aneurysms using an albumin binding probe
N2 - Abdominal aortic aneurysm (AAA) remains a fatal disease. Its development encompasses a complex interplay between hemodynamic stimuli on and changes in the arterial wall. Currently available biomarkers fail to predict the risk of AAA rupture independent of aneurysm size. Therefore, novel biomarkers for AAA characterization are needed. In this study, we used a mouse model of AAA to investigate the potential of magnetic resonance imaging (MRI) with an albumin-binding probe to assess changes in vascular permeability at different stages of aneurysm growth. Two imaging studies were performed: a longitudinal study with follow-up and death as endpoint to predict rupture risk and a week-by-week study to characterize AAA development. AAAs, which eventually ruptured, demonstrated a significantly higher in vivo MR signal enhancement from the albumin-binding probe (p = 0.047) and a smaller non-enhancing thrombus area compared to intact AAAs (p = 0.001). The ratio of albumin-binding-probe enhancement of the aneurysm wall to size of non-enhancing-thrombus-area predicted AAA rupture with high sensitivity/specificity (100%/86%). More advanced aneurysms with higher vascular permeability demonstrated an increased uptake of the albumin-binding-probe. These results indicate that MRI with an albumin-binding probe may enable noninvasive assessment of vascular permeability in murine AAAs and prediction of rupture risk.
KW - Magnetic resonance imaging
KW - Imaging
KW - Tomography
KW - Gadolinium
KW - Contrast agent
KW - Atherosclerosis
KW - ICP-MS
KW - Gadofosveset
KW - Angiography
KW - LA-ICP-MS
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525541
DO - https://doi.org/10.1038/s41598-020-59842-2
VL - 10
SP - Article number: 3231
PB - Springer Nature Limited
CY - London, New York, Berlin, Shanghai and Tokyo
AN - OPUS4-52554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kabelitz, Anke
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Joester, Maike
A1 - Reinholz, Uwe
A1 - Radtke, Martin
A1 - Bienert, Ralf
A1 - Schulz, K.
A1 - Schmack, R.
A1 - Kraehnert, R.
A1 - Emmerling, Franziska
T1 - Time-resolved in situ studies on the formation mechanism of iron oxide nanoparticles using combined fast-XANES and SAXS
N2 - The reaction of iron chlorides with an alkaline reagent is one of the most prominent methods for the synthesis of iron oxide nanoparticles. We studied the particle formation mechanism using triethanolamine as reactant and stabilizing agent. In situ fast-X-ray absorption near edge spectroscopy and small-angle X-ray scattering provide information on the oxidation state and the structural information at the same time. In situ data were complemented by ex situ transmission electron microscopy, wide-angle X-ray scattering and Raman analysis of the formed nanoparticles. The formation of maghemite nanoparticles (γ-Fe2O3) from ferric and ferrous chloride was investigated. Prior to the formation of these nanoparticles, the formation and conversion of intermediate phases (akaganeite, iron(II, III) hydroxides) was observed which undergoes a morphological and structural collapse. The thus formed small magnetite nanoparticles (Fe3O4) grow further and convert to maghemite with increasing reaction time.
KW - oxidation state
KW - structural information
KW - maghemite
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351376
DO - https://doi.org/10.1039/C5CE01585E
SN - 1466-8033
VL - 17
IS - 44
SP - 8463
EP - 8470
CY - London, UK
AN - OPUS4-35137
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilke, Manuel
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Reinholz, Uwe
A1 - Rademann, Klaus
A1 - Emmerling, Franziska
T1 - The structure and in situ synthesis investigation of isomorphic mononuclear molecular metal phenylphosphonates
N2 - We describe a fast and effective synthesis for molecular metal phosphonates. Isomorphic compounds [M(II)(HO₃PPh)₂(H₂O₃PPh)₂(H₂O)₂] (M = Mn (1), Co (2), Ni (3); Ph = C₆H₅) were obtained by grinding. The complexes are mononuclear compounds containing neutral and monodeprotonated phenylphosphonic acid and water as ligands. The crystal structures were determined using powder X-ray diffraction (PXRD) data and validated by extended X-ray absorption fine structure (EXAFS) data. Combined synchrotron XRD measurements and Raman spectroscopy were conducted for investigating the reactions in situ. Based on these data, the intermediates were characterized and the formation mechanism was derived.
KW - Mechanochemistry
KW - Metal phosphonate
KW - In situ
KW - XRD
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-363944
DO - https://doi.org/10.1039/c6dt00787b
SN - 1477-9226
SN - 1477-9234
SN - 1364-5447
VL - 45
IS - 23
SP - 9460
EP - 9467
AN - OPUS4-36394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nguyen, Thi Yen
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - Direct evidence of polyamorphism in paracetamol
N2 - While polymorphism is a common phenomenon in the crystallization processes of organic compounds, polyamorphism has gained importance only recently. Using sophisticated sample environments and applying in situ scattering methods and vibrational spectroscopy, the complete crystallization process of organic compounds from solution can be traced and characterized. Diffuse scattering from amorphous intermediates can be investigated by analyzing the atomic pair distribution function (PDF) to gain further insights into molecular pre-orientation. The crystallization behavior of paracetamol was studied exemplarily under defined, surface-free conditions. Based on the choice of the solvent, the formation of different polymorphs is promoted. The thermodynamically stable form I and the metastable orthorhombic form II could be isolated in pure form directly from solution. For both polymorphs, the crystallization from solution proceeds via a distinct amorphous precursor phase. PDF analyses of these different amorphous states indicate a specific pre-orientation of the analyte molecules introduced by the solvent. The resulting crystalline polymorph is already imprinted in these proto-crystalline precursors. Direct experimental evidence for the polyamorphism of paracetamol is provided.
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351366
DO - https://doi.org/10.1039/C5CE01583A
SN - 1466-8033
VL - 17
IS - 47
SP - 9029
EP - 9036
PB - Royal Society of Chemistry
CY - London, UK
AN - OPUS4-35136
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilke, Manuel
A1 - Batzdorf, Lisa
A1 - Fischer, Franziska
A1 - Rademann, Klaus
A1 - Emmerling, Franziska
T1 - Cadmium phenylphosphonates: preparation, characterisation and in situ investigation
N2 - The successful mechanochemical syntheses of three cadmium phenylphosphonates indicates that mechanochemistry is ideally suited for synthesizing metal phosphonates. With this powerful synthesis tool it is possible to synthesize rapidly and efficiently both known and novel phosphonates. The Crystal structures of the two new compounds, and, were solved from PXRD data. They contain monodeprotonated phenylphosphonate and neutral phenylphosphonic acid ligands. The synthesis pathways of all three compounds were investigated in situ. A diffusion mechanism is corroborated by our findings.
Intermediates could be detected and identified. The kinetically favored product (3) could always be detected during the syntheses. The thermodynamic stability of the compounds and the stoichiometric ratio of the starting materials are the two directing factors for the synthesis of the final products.
KW - Mechanochemistry
KW - Metal phosphonate
KW - In situ
KW - MOF
KW - XRD
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-363322
DO - https://doi.org/10.1039/c6ra01080f
SN - 2046-2069
VL - 6
IS - 42
SP - 36011
EP - 36019
PB - Royal Soc Chemistry
CY - Cambridge, UK
AN - OPUS4-36332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Reinholz, Uwe
A1 - Riesemeier, Heinrich
A1 - Emmerling, Franziska
T1 - Time- & spatial-resolved X-ray absorption fine structure (XAFS) spectroscopy in a single-shot – new analytical possibilities for in situ material characterization
N2 - A new concept that comprises both time- and lateral-resolved X-ray absorption fine-structure information simultaneously in a single shot is presented. This uncomplicated set-up was tested at the BAMline at BESSY-II (Berlin, Germany). The primary broadband beam was generated by a double multilayer monochromator. The transmitted beam through the sample is diffracted by a convexly bent Si (111) crystal, producing a divergent beam. This, in turn, is collected by either an energy-sensitive area detector, the so-called color X-ray camera, or by an area-sensitive detector based on a CCD camera, in θ-2θ geometry. The first tests were performed with thin metal foils and some iron oxide mixtures. A time resolution of lower than 1 s together with a spatial resolution in one dimension of at least 50 µm is achieved.
KW - Time resolution
KW - Single-shot XAFS
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-370892
DO - https://doi.org/10.1107/S1600577516003969
SN - 1600-5775
IS - 23
SP - 769
EP - 776
PB - International Union of Crystallography
CY - Chester, UK
AN - OPUS4-37089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Franziska
A1 - Scholz, G.
A1 - Benemann, Sigrid
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - Evaluation of the formation pathways of cocrystal polymorphs in liquid-assisted syntheses
N2 - The synthesis of the polymorphic cocrystal caffeine:anthranilic acid was investigated to obtain a better understanding of the processes leading to the formation of different polymorphic forms. In the case of these cocrystal polymorphs synthesized by liquid-assisted grinding a distinct influence of the dipole moment of the solvent was found. A pre-coordination between the solvent molecules and the caffeine:anthranilic acid cocrystal could be identified in the formation of form II. In the case of form II the solvent can be regarded as a catalyst. The formation pathway of each polymorph was evaluated using synchrotron X-ray diffraction.
KW - cocrystal
KW - synchrotron X-ray diffraction
KW - caffeine
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313222
DO - https://doi.org/10.1039/c4ce00472h
SN - 1466-8033
VL - 16
IS - 35
SP - 8272
EP - 8278
CY - London, UK
AN - OPUS4-31322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fischer, Franziska
A1 - Scholz, G.
A1 - Batzdorf, Lisa
A1 - Wilke, Manuel
A1 - Emmerling, Franziska
T1 - Synthesis, structure determination, and formation of a theobromine: oxalic acid 2:1 cocrystal
N2 - The structure and the formation pathway of a new theobromine : oxalic acid (2 : 1) cocrystal are presented. The cocrystal was synthesised mechanochemically and its structure was solved based on the powder X-ray data. The mechanochemical synthesis of this model compound was studied in situ using synchrotron XRD. Based on the XRD data details of the formation mechanism were obtained. The formation can be described as a self-accelerated ('liquid like') process from a highly activated species.
KW - ssNMR spectroscopy
KW - Synchrotron measurements
KW - API molecule
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-331567
DO - https://doi.org/10.1039/c4ce02066a
SN - 1466-8033
VL - 17
IS - 4
SP - 824
EP - 829
CY - London, UK
AN - OPUS4-33156
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abbott, A. P.
A1 - Abolibda, T. Z.
A1 - Davis, S.J.
A1 - Emmerling, Franziska
A1 - Lourdin, D.
A1 - Leroy, E.
A1 - Wise, W. R.
T1 - Glycol based plasticisers for salt modified starch
N2 - Starch is one of the most common and easily obtained natural polymers, making it attractive as a potential bio-based alternative to synthetic polymers. This study shows that a simple quaternary ammonium salt combined with urea or glycols forms effective modifiers that produce flexible plastics with good mechanical properties that are comparable to some polyolefin plastics. The processing conditions are shown to significantly affect the structure of the polymer which has a concomitant effect upon the mechanical and physical properties of the resulting plastic. Using a glycerol based modifier results in a totally sustainable and biodegradable material which can be injection moulded.
KW - biodegradable material
KW - flexible plastics
KW - injection moulded
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-351426
DO - https://doi.org/10.1039/C4RA06220E
SN - 2046-2069
VL - 4
IS - 76
SP - 40421
EP - 40427
PB - RSC Publishing
CY - London
AN - OPUS4-35142
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wilke, Manuel
A1 - Klimakow, Maria
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - Fast and efficient synthesis of a host guest system: a mechanochemical approach
N2 - An unusually fast and effective synthesis procedure for a host guest system consisting of a metal organic framework (MOF) and a polyoxometalate (POM) is described. The material was synthesised mechanochemically and the evolution of the structure was monitored ex and in situ using synchrotron X-ray diffraction (XRD).
KW - Mechanochemistry
KW - MOF
KW - in situ
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354910
UR - http://pubs.rsc.org/en/Content/ArticleLanding/2016/CE/C5CE01868D#!divAbstract
DO - https://doi.org/10.1039/C5CE01868D
VL - 18
IS - 7
SP - 1096
EP - 1100
AN - OPUS4-35491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pavlidis, Sotirios
A1 - Fischer, Eric W.
A1 - Opis-Basilio, Amanda
A1 - Bera, Ayan
A1 - Guilherme Buzanich, Ana
A1 - Álvarez-Sánchez, María
A1 - Wittek, Severin
A1 - Emmerling, Franziska
A1 - Ray, Kallol
A1 - Roemelt, Michael
A1 - Abbenseth, Josh
T1 - Ambiphilic Reactivity and Switchable Methyl Transfer at a T-Shaped Bi(NNN) Complex Enabled by a Redox-Active Pincer Ligand
N2 - We report the transition-metal-like reactivity of a geometrically constrained, ambiphilic bismuth(III) trisamide. Planarization of the Bi(III) center unlocks Bi−C bond formation when reacted with mild electrophiles (alkyl iodides and triflates) accompanied by two-electron oxidation of the utilized NNN pincer nligand. The preservation of the bismuth oxidation state is confirmed by single-crystal X-ray diffraction and X-ray absorption spectroscopy and corroborated by theoretical calculations. Sequential reduction of the oxidized ligand framework alters the reactivity of a generated Bi−Me unit, enabling controlled access to methyl cation, radical, and anion equivalents. The full [Bi(Me)(NNN)]+/•/− redox series was comprehensively characterized using NMR and EPR spectroscopy as well as spectro-electrochemistry. This work represents the first example of ligand-assisted, redox-neutral C−X bond splitting at bismuth, establishing a new paradigm for synthetic bismuth chemistry.
KW - Pincer ligand
KW - XAS
KW - Redox
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654948
DO - https://doi.org/10.1021/jacs.5c18955
SN - 0002-7863
VL - 148
IS - 2
SP - 2683
EP - 2692
PB - American Chemical Society (ACS)
AN - OPUS4-65494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chakraborty, Gouri
A1 - Das, Prasenjit
A1 - Bhattacharya, Biswajit
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Thomas, Arne
T1 - Room-temperature superprotonic conductivity in COOH-functionalized multicomponent covalent organic frameworks
N2 - In solid materials, the development of hydrogen bonding (H-bonding) networks within pores is crucial for efficient proton conductance. In this study, a chemically stable carboxylic acid-functionalized, quinoline-linked 2D microporous covalent organic framework (COF) (Qy-COOH) was synthesized using the Doebner multicomponent reaction (MCR) and compared to a similar framework lacking the –COOH functionality (Qy-H), prepared via an MC Domino reaction. The proton conductivity of the –COOH-functionalized MCR-COF was significantly enhanced, reaching 10−2 S cm−1, attributed to strong H-bonding interactions between water molecules and the dangling –COOH groups within the COF pores. In contrast, the analogous Qy-H framework exhibited a much lower proton conductivity of 10−5 S cm−1, while an imine-based COF showed only 10−6 S cm−1. This work represents the first demonstration of a general strategy to achieve efficient proton conduction in a class of layered 2D –COOH-functionalized COFs, offering superprotonic conductivity without requiring additives at room temperature. The MCR-COF design approach provides a promising pathway for developing highly stable and high-performance proton-conducting materials.
KW - Multicomponebt
KW - COF
KW - Proton Conductivity
KW - Superprotonic
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653526
DO - https://doi.org/10.1039/D5SC06953J
SN - 2041-6520
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65352
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmalz, Alina
A1 - Eby, Charles Gaston
A1 - Moss, Caitlin
A1 - Bhattacharya, Biswajit
A1 - Emmerling, Franziska
T1 - Thermally Robust 1D Cu(I) Phosphonate Coordination Polymer Exhibiting Enhanced Proton Conductivity via Humidity‐Driven Pathways
N2 - The development of thermally stable solid-state proton conductors (SSPCs) is crucial for advancing energy-conversion devices such as proton-exchange membrane fuel cells (PEMFCs). In this work, we report the solvothermal synthesis and characterization of a novel, 1D Cu(I) coordination polymer, {Cu(ADP)0.5(BPY)}n (BAM-5), based on anthracenediylphosphonate (H2ADP) and 4,40 -bipyridine (BPY). Single-crystal X-ray diffraction revealed that BAM-5 crystallizes in the triclinic space group P1 and shows a 1D ladder structure connected by the H2ADP and organic BPY linkers, which is assembled into a 2D layer via O−H···O hydrogen bonding interactions between uncoordinated oxygen and the O−H of the phosphonate group. Thermogravimetric and dynamic water sorption analysis demonstrated exceptional thermal robustness of BAM-5 until 230°C and notable water affinity. Proton conductivity measurements found increasing proton conductive properties with increasing temperature and relative humidity.The latter is correlated with the material’s water uptake since the structure itself does not contain any permanent lattice water molecules. A maximum proton conductivity of 6.6 × 10−6 S cm−1 was found at 80°C and 98% RH. To the best of our knowledge, no dense, nonporous 1D coordination polymer without lattice or coordinated solvent molecules has shown comparable proton con� ductivity. The high activation energy suggests a combination of both, a Grotthuss-type proton hopping through the hydrogen� bonded framework, and a vehicular process, in which protons are carried along with absorbed water molecules.
KW - Coordination polymers
KW - Phosphonate ligand
KW - Proton conduction
KW - X-ray diffraction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651382
DO - https://doi.org/10.1002/zaac.202500187
SN - 0044-2313
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-65138
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bandow, N.
A1 - Aitken, M. D.
A1 - Geburtig, Anja
A1 - Kalbe, Ute
A1 - Piechotta, Christian
A1 - Schoknecht, Ute
A1 - Simon, Franz-Georg
A1 - Stephan, Ina
T1 - Using Environmental Simulations to Test the Release of Hazardous Substances from Polymer-Based Products: Are Realism and Pragmatism Mutually Exclusive Objectives?
N2 - The potential release of hazardous substances from polymer-based products is currently in the focus of environmental policy. Environmental simulations are applied to expose such products to selected aging conditions and to investigate release processes. Commonly applied aging exposure types such as solar and UV radiation in combination with water contact, corrosive gases, and soil contact as well as expected general effects on polymers and additional ingredients of polymer-based products are described. The release of substances is based on mass-transfer processes to the material surfaces. Experimental approaches to investigate transport processes that are caused by water contact are presented. For tailoring the tests, relevant aging exposure types and release quantification methods must be combined appropriately. Several studies on the release of hazardous substances such as metals, polyaromatic hydrocarbons, flame retardants, antioxidants, and carbon nanotubes from polymers are summarized exemplarily. Differences between natural and artificial exposure tests are discussed and demonstrated for the release of flame retardants from several polymers and for biocides from paints. Requirements and limitations to apply results from short-term artificial environmental exposure tests to predict long-term environmental behavior of polymers are presented.
KW - Environmental simulations
KW - Polymer-based products
KW - Artificial weathering
KW - Degradation
KW - Leaching
KW - Soil contact
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509310
DO - https://doi.org/10.3390/ma13122709
SN - 1996-1944
VL - 13
IS - 12
SP - Paper 2709, 22
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tuma, Dirk
A1 - Mady, A. H.
A1 - Baynosa, M. L.
A1 - Saad, M.
A1 - Dhakal, G.
A1 - Kim, W. K.
A1 - Shim, Jae-Jin
T1 - Morphology-engineered hollow NiTiO₃/C–Ag/Ag₃PO₄ S-scheme heterojunction photocatalyst: mechanistic insights into sunlight-driven tetracycline degradation
N2 - Tetracycline (TCH), a widely used antibiotic, persists in aquatic and terrestrial environments, posing ecological risks and accelerating antibiotic resistance. To address this, we report a hollow-structured NiTiO₃/C–Ag/Ag₃PO₄ (NT/C–AAP)
photocatalyst—the first hollow-type nickel titanate—synthesized via a self-template solvothermal route followed by photodeposition. The catalyst integrates key design strategies—hollow architecture, oxygen vacancies, carbon coating, and an S-scheme heterojunction—to optimize photocatalytic performance. The hollow structure enhances light harvesting via internal scattering, oxygen vacancies facilitate O2 adsorption and superoxide (O₂•⁻) generation, and the S-scheme heterojunction effectively suppresses electron–hole recombination while preserving strong redox potential. NT/C–AAP achieved 96% TCH degradation within 1 h and 82% mineralization in 3 h under solar light, far exceeding core–shell (18%) and aggregated (47%) NiTiO₃-based catalysts. Complete removal was realized within 40 min under 400 W visible light. The catalyst maintained 96% activity after five cycles, confirming excellent durability. Compared with previously reported NiTiO₃ photocatalysts, NT/C–AAP delivered a 50–400% performance enhancement arising from its engineered hollow structure and improved electronic properties. Mechanistic studies identified O₂•⁻ and •OH radicals as dominant species, validating the role of morphology and interface engineering in directing charge separation and redox activity. Additionally, a catalyst performance index was proposed to facilitate comparison across diverse conditions. Overall, this work introduces a novel, durable photocatalyst that links structural design to functional performance and demonstrates strong potential for practical environmental remediation.
KW - Heterojunction photocatalyst
KW - Photodegradation
KW - Tetracycline
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655946
DO - https://doi.org/10.1007/s42114-025-01600-x
SN - 2522-0128
VL - 9
IS - 2
SP - 1
EP - 19
PB - Springer Nature
CY - London
AN - OPUS4-65594
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwibbert, Karin
A1 - de Eulate Pérez, Elisa García
A1 - Wen, Keqing
A1 - Voss, Heike
A1 - Thiele, Dorothea
A1 - Richter, Anja M.
A1 - Bonse, Jörn
T1 - Escherichia coli repellence via laser-induced periodic surface structures (LIPSS) on titanium: Critical role of biofilm-associated gene expression
N2 - The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Titanium
KW - Biofilm
KW - Antifouling
KW - Gene expression
KW - Fluorescence microscopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655572
DO - https://doi.org/10.1016/j.apsusc.2026.166363
SN - 0169-4332
VL - 730
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sauer, Hannah
A1 - Okpeke, Bright E.
A1 - Dzielendziak, Agnieszka S.
A1 - Eberwein, Robert
A1 - Baetcke, Lars
A1 - Ehlers, Sören
T1 - Comparative life cycle assessment of vacuum insulation panel core materials for liquid hydrogen storage tanks – glass bubbles compared to conventional core materials
N2 - The environmental performance of insulation materials for liquid hydrogen storage tank application is important to the development of sustainable supply chains. As new materials keep evolving, there is a need to assess their environmental impact. Therefore, this study investigates the environmental sustainability and circularity of cryogenic insulation concepts, namely vacuum insulation panels (VIPs), exclusively focussing on their core materials. Employing a cradle-to-grave life cycle assessment model, the VIP core materials are investigated with a special focus on glass bubbles. Based on the results, the global warming potential of the considered core materials, namely, glass bubbles, silica aerogel, fumed silica, expanded perlite, glass fibre, and polyurethane foam is 9.21∗10^−2, 7.00, 2.50∗10^−1, 3.63∗10^−2, 6.68∗10^−2, and 1.88 kg CO2 eq. per functional unit, respectively. In general, silica aerogel and polyurethane foam are the least environmentally friendly materials, while the most sustainable is expanded perlite, followed by glass fibre, glass bubbles, and fumed silica.
KW - LH2
KW - Insulation
KW - Cryogenic storage tank
KW - Life Cycle Assessment
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655445
DO - https://doi.org/10.1016/j.ijhydene.2026.153937
SN - 0360-3199
VL - 219
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-65544
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudhuri, Somsubhro
A1 - Krankenhagen, Rainer
A1 - Lapšanská, Ivana
A1 - Stamm, Michael
T1 - Modeling Temperature Responses of a Wind Turbine Blade Section Under Climate Chamber Conditions – Part 1: Challenges for FEM Simulations
N2 - The rapid expansion of wind energy infrastructure over the past 20–30 years has led up to a situation where advanced non‐destructive testing (NDT) technologies are the need‐of‐the‐hour, not only for new wind turbine blades (WTBs) that are being installed, but also for older infrastructure which is reaching their designed lifetime. NDT technologies that improve both the quality as well as reduce the time required for the inspection are sought after, and one such example is passive infrared thermography (IRT). For passive IRT to provide significant information/insight into the integrity of the WTB, there needs to exist certain thermal contrast to both visualize and distinguish between features in WTB. These features could be surface features, subsurface structure or defects. The temperature variations due to air temperature fluctuations and the sun assist (passively) to obtain the necessary thermal contrast. To better understand the thermal response of composite structures such as WTBs, a validation study was conducted using a WTB section subjected to controlled temperature transients within a climate chamber, without external irradiation. Infrared measurements were recorded using a thermographic camera, and the same specimen was modeled using finite element methods (FEM) in COMSOL Multiphysics. While a direct validation of the simulation is limited due to transient and unmeasured variables in the experimental data, qualitative comparison provides valuable insight into the applicability of FEM for predicting thermal behavior in passive IRT scenarios. This article represents the first part of a two‐part study, focusing on the FEM modeling approach and associated challenges. The second part will address the experimental investigation in more detail, with an emphasis on thermal contrast behavior under varied transient conditions.
KW - Finite element modeling
KW - Non- destructive testing
KW - Passive infrared thermography
KW - Thermal contrast
KW - Wind turbine blades
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655330
DO - https://doi.org/10.1002/we.70102
SN - 1095-4244
VL - 29
IS - 3
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-65533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czeskleba, Denis
A1 - Rhode, Michael
A1 - Wandtke, Karsten
A1 - Irfan, Muhammad Dary
A1 - Kannengiesser, Thomas
T1 - Hydrogen diffusion in thick-walled S690 saw joints: part 1—experimental determination of microstructure-dependent diffusion coefficients
N2 - High-strength low-alloyed steel S690 is widely used in heavy-duty applications, such as structural components, mobile cranes, and industrial plant construction, owing to their high strength and weldability. However, thick-plate submerged arc welding (SAW) can introduce elevated hydrogen levels and residual stresses that promote time-delayed hydrogen-assisted
cold cracking (HACC). Accurate, microstructure-specific diffusion data are scarce, limiting predictive HACC assessments. This study presents an experimental determination of hydrogen diffusion coefficients (DH) in two S690 variants: thermomechanically rolled (S690MC) and quenched and tempered (S690Q). Multi-layer SAW welds were produced from 30 mm thick plate material at three heat input levels, and diffusion membranes were extracted from weld metal (WM), heat-affected zone (HAZ), and base material (BM). Hydrogen permeation tests, conducted in accordance with DIN En ISO 17081, yielded flux curves normalized in time from which DH was derived using the inflection-point method. At room temperature, DH values ranged from 6 × 10−5 mm2/s to 9 × 10−5 mm2/s across all regions and heat inputs, with no significant difference between S690MC and S690Q. Weld metal exhibited marginally lower DH, attributed to enhanced hydrogen trapping, while base material measurements showed greater variability. These microstructure-resolved diffusion coefficients add quantitative data for modern S690 SAW welds and provide internally consistent input parameters for the numerical simulations presented in part 2. The results support improved parameterization for subsequent assessments of HACC risk through the optimization of welding parameters.
KW - Hydrogen assisted cracking
KW - Submerged arc welding
KW - Diffusion
KW - Electrochemical permeation
KW - Microstructure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655711
DO - https://doi.org/10.1007/s40194-026-02400-7
SN - 0043-2288
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-65571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Czeskleba, Denis
A1 - Rhode, Michael
A1 - Wandtke, Karsten
A1 - Irfan, Muhammad Dary
A1 - Kannengiesser, Thomas
T1 - Hydrogen diffusion in thick-walled S690 SAW joints: part 2 – predictive modeling of heat input and microstructure influence
N2 - High-strength low-alloy (HSLA) steels such as S690 are widely employed in thick-walled welded structures, where hydrogen-assisted cold cracking (HACC) remains a persistent concern. While microstructure-specific hydrogen diffusion coefficients (DH) for weld metal (WM), heat-affected zone (HAZ), and base material (BM) were experimentally established in Part 1 of this study, their quantitative influence on hydrogen accumulation and effusion has not yet been fully clarified. This work presents a transient, spatially resolved numerical model for simulating hydrogen transport in multi-pass submerged arc welds. The model integrates experimentally determined DH values with realistic thermal cycles and temperature-dependent boundary conditions. Developed in Python, the simulation tool is purpose-built for hydrogen diffusion in welded joints. It offers a focused, transparent alternative. It offers a focused, transparent alternative to general-purpose finite element platforms. Parametric analyses demonstrate that, although the diffusion coefficients vary by up to 50%, their impact on overall hydrogen retention is minor. In contrast, plate thickness, bead geometry, cooling time (t₈/₅), and interpass temperature exert a dominant influence on hydrogen distribution. Despite clear microstructural differences between the thermomechanically rolled (S690MC) and quenched and tempered (S690Q) variants, including opposite HAZ hardness responses (softening in S690MC, hardening in S690Q) in the (pen)ultimate weld bead, the simulations confirm that their diffusion behavior and hydrogen solubility are closely aligned. Consequently, differences in DH and solubility exert only a minor influence on hydrogen retention compared to thermal exposure and joint geometry. These findings support the interchangeable use of both steel grades in terms of HACC risk due to hydrogen diffusion kinetics under comparable welding conditions.
KW - Hydrogen assisted cracking
KW - Numerical simulation
KW - Diffusion
KW - Submerged arc welding
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655721
DO - https://doi.org/10.1007/s40194-026-02395-1
SN - 0043-2288
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-65572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jaffer, Yousuf Dar
A1 - Abdolahpur Monikh, Fazel
A1 - Nguyen, Nhung H.A.
A1 - Sevcu, Alena
A1 - Abdulkadir, Nafiu
A1 - Raha, Jakub
A1 - Katsumiti, Alberto
A1 - Bilbao, Ainhoa
A1 - Altman, Korinna
A1 - Grossart, Hans-Peter
T1 - Bio-based microplastics increase the horizontal transfer of antibiotic resistance genes in aquatic environments
N2 - The role of microplastics as vectors for horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) is increasingly recognized. This study investigated whether bio-based microplastics, often promoted as environmentally friendly alternatives, exhibit similar or enhanced HGT potential compared to conventional plastics. We examined the HGT rates of the trimethoprim resistance gene (dfrA1) and tetracycline resistance gene (tetA), carried on a broad-host-range plasmid, among Escherichia coli (donor) and Vibrio parahaemolyticus, Pseudomonas sp., or a natural lake microbial community (recipients). Four bio-based polymer types—polylactic acid (PLA) granules, commercial PLA, high-density polyethylene (HDPE) granules, and poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV)- were compared with two conventional microplastics, polyethylene terephthalate (PET) and bottle-derived HDPE. The bio-based microplastics exhibited significantly higher HGT frequencies, with a 21–48-fold increase compared to control chitosan in single-strain experiments and a 13-fold increase within the lake microbial community. 16S rRNA amplicon sequencing revealed distinct bacterial community compositions colonizing different microplastic types in the lake water. The transconjugant communities, indicative of successful HGT events, were strongly influenced by microplastic type. While Nannocystis was generally dominant, the PLA (granule) microplastic exhibited a unique profile dominated by Candidatus Megaira and Niveispirillum. Additionally, Flavobacterium and Fluviicola were uniquely detected as transconjugants on HDPE (granule). These findings demonstrate that bioplastics have a significant influence on the selective enrichment of specific transconjugant genera, suggesting a prominent role of microplastics, particularly bio-based plastics, in shaping ARG dissemination within complex microbial ecosystems. We recommend a comprehensive risk assessment of bio-based plastics, particularly their potential to enhance the spread of ARGs, before their widespread implementation in consumer products.
KW - Microplastics
KW - Bioplastics
KW - Conventional plastics
KW - Antibiotik resistence gene
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656293
DO - https://doi.org/10.1016/j.impact.2026.100613
SN - 2452-0748
VL - 41
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65629
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mojsak, Mateusz
A1 - Bodo, Filippo
A1 - Erba, Alessandro
A1 - Michalchuk, Adam A. L.
A1 - Kraka, Elfi
T1 - Local Vibrational Mode Analysis of Phonon Dispersion Relations in Crystals
N2 - We present a general framework for performing local vibrational mode analysis of vibrations in crystalline materials at arbitrary wavevectors throughout the Brillouin zone. The approach enables phonon dispersion relations to be interpreted in terms of chemically meaningful interatomic interactions and structural motifs, providing direct insight into the microscopic origins of the phonon behavior in periodic systems. We demonstrate the methodology for representative one-, two-, and three-dimensional materials including polymeric chains, graphene, and prototypical rock-salt and perovskite crystals. Across these systems, the analysis reveals how specific bonding patterns and structural features govern phonon dispersion relations. This framework provides a quantitative tool for the chemically intuitive analysis of phonon spectra and offers a pathway toward the rational design of phonon-dependent properties in crystalline materials.
KW - Phonons
KW - Molecular Crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656430
DO - https://doi.org/10.1021/acs.jctc.6c00097
SN - 1549-9618
SP - 1
EP - 16
PB - American Chemical Society (ACS)
AN - OPUS4-65643
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - GEN
A1 - Mrkwitschka, Paul
A1 - Hodoroaba, Vasile-Dan
A1 - Radnik, Jörg
T1 - XPS/HAXPES and EDS spectra with ROI
N2 - XPS/HAXPES spectra as well as EDS spectra and SEM micrographs with regions of interest. Measurement scheme included as a powerpoint presentation.
Investigated materials: Ionic liquid and commercial and lab-synthesized graphene oxide.
KW - EDX
KW - XPS
KW - Graphene Oxide
KW - Ionic Liquid
PY - 2026
DO - https://doi.org/10.5281/zenodo.18231732
PB - Zenodo
CY - Geneva
AN - OPUS4-65624
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rodríguez‐Sánchez, Noelia
A1 - Ballesteros, Menta
A1 - Prinz, Carsten
A1 - Canosa, Inés
A1 - Flores Díaz, Amando
A1 - Bhattacharya, Biswajit
A1 - Ruiz‐Salvador, A. Rabdel
A1 - Emmerling, Franziska
T1 - Mechanochemical Fullerene Nanoencapsulation in Amino‐Functionalized ZIF‐12 for Visible‐Light Disinfection of Waterborne Viruses and Bacteria
N2 - Water contamination poses a significant threat to public health and environmental sustainability, necessitating the development of efficient purification technologies. This study reports the mechanochemical synthesis of an amino-functionalized ZIF 12 framework with encapsulated fullerene (C60) as a bifunctional photocatalyst for water decontamination and disinfection under visible-light irradiation. The samples were characterized using powder X-ray diffraction (PXRD), FT-IR spectroscopy, N2 adsorption isotherm, X-ray photoelectron spectroscopy (XPS), electron microscopy (SEM and TEM), thermogravimetric Analysis (TGA), and UV–vis diffuse reflectance spectroscopy (DRS), confirming the retention of crystallinity and effective incorporation of C60 and amino groups within the framework. Fullerene loading and amino functionalization modified the optical properties, extending visible light absorption and enhancing charge separation and photocatalytic activity. The synergistic interaction between amino groups and C60 promotes efficient charge separation and enhanced hydroxyl radical production, resulting in improved photocatalytic and photo-Fenton activity. C60@ZIF-12-NH2 exhibited excellent photocatalytic performance, achieving the completeinactivation of bacteriophage P22 under saline conditions and effective disinfection of E.coli and coliforms innatural river water, demonstrating robustness under environmentally relevant conditions. The solvent-minimized mechanochemical synthesis and visible-light-driven activity position the C60@ZIF-12-NH2 composite as a promising platform for sustainable and advanced water treatment applications.
KW - Fullerene
KW - Heterogeneous photo-Fenton
KW - Mechanochemistry
KW - Nanoencapsulation
KW - Photocatalysis
KW - ZIF-12
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656531
DO - https://doi.org/10.1002/smll.202512881
SN - 1613-6810
SP - 1
EP - 19
PB - Wiley-VCH GmbH
AN - OPUS4-65653
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rösler, Alexander
A1 - Weidner, Steffen
A1 - Klamroth, Tillmann
A1 - Müller, Axel HE
A1 - Schlaad, Helmut
T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents
N2 - AbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
KW - Myrcene
KW - Anionic polymerization
KW - MALDI TOF MS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649039
DO - https://doi.org/10.1002/pi.6772
SN - 0959-8103
SP - 1
EP - 8
PB - Wiley
AN - OPUS4-64903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Sahre, Mario
A1 - Corrao, Elena
A1 - Pellegrino, Francesco
A1 - Alonso, Beatriz
A1 - Zurutuza, Amaia
A1 - Radnik, Jörg
A1 - Hodoroaba, Vasile-Dan
T1 - Standardized Elemental Composition Analysis of Graphene‐Related 2D Materials (GR2M) With SEM/EDS and XPS Works Reliably
N2 - Reliable quantification of the chemical composition of graphene‐related 2D materials (GR2M) as powders and liquid suspensions is a challenging task. Analytical methods such as X‐ray photoelectron spectroscopy (XPS), inductively coupled plasma mass spectrometry (ICP‐MS), thermogravimetric analysis (TGA) and Fourier transform infrared spectroscopy (FTIR) are recommended by standardization bodies. The specific parameters to be measured are also defined, e.g., the oxygen‐to‐carbon (O/C) atomic ratio, the trace metal impurities, or the functional groups. In this contribution, for the first time, results of a systematic study on the capability of energy‐dispersive X‐ray spectroscopy (EDS) at a scanning electron microscope (SEM) to reliably quantify the O/C ratio and impurities remained from the synthesis of selected GR2M are reported. The robustness of SEM/EDS analysis is verified for various measurement conditions (different excitations and EDS detectors) and the validity of the results is tested by comparison to the established XPS analysis. Moreover, an ionic liquid is used as a reference material for the quantification of the light elements such as C, N, O and F. The study clearly demonstrates the reliability of the fast and widely available SEM/EDS as a standard method for the quantification of the elemental composition of GR2M and generally of light materials.
KW - Graphene oxide flakes
KW - Impurities
KW - O/C ratio
KW - SEM/EDS
KW - Standard
KW - XPS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656748
DO - https://doi.org/10.1002/smll.202511283
SN - 1613-6810
SP - 1
EP - 10
PB - Wiley-VHC GmbH
AN - OPUS4-65674
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Aliyah, K.
A1 - Berger, A.
A1 - Lazaridis, T.
A1 - Appel, C.
A1 - Prehal, C.
A1 - Menzel, A.
A1 - Guizar-Sicairos, M.
A1 - Smales, Glen J.
A1 - Pauw, Brian Richard
A1 - Gasteiger, H. A.
A1 - Gubler, L.
A1 - Büchi, F. N.
A1 - Eller, J.
T1 - Impact of Microporous Layer Composition on the Water Content in the Membrane Electrode Assembly of Polymer Electrolyte Fuel Cells
N2 - Polymer electrolyte fuel cells are paramount for future emission-free mobility. One of the vital challenges for prospering commercialization of PEFCs is water management in the cells. A microporous layer (MPL) is typically positioned between the gas Diffusion layer (GDL) and the catalyst layer (CL) to boost the cell performance and facilitate water management. In this study, three different MPLs were investigated, namely, carbon black-based MPLs with different PTFE binder contents (20 wt % PTFE as a base case and 40 wt % PTFE), as well as perforated MPLs with micron-sized pores coated on the same GDL- Substrate (Freudenberg H14). The water content in the membrane, catalyst layers (CL), and MPLs was explored using operando scanning small- and wide-angle X-ray scattering (S/WAXS). At Tcell = 80 °C, relative humidity = 100%, pabs = 3 bar, the MPL with larger pores exhibits slightly higher performance than the base case, while a considerably lower cathode CL and MPL saturation levels were observed for the MPL. In contrast, the MPL with higher amounts of PTFE binder shows lower performance than the base case, with considerably higher cathode CL and MPL saturation levels. 3D representations of how the pores could be filled in the cathode CLs were obtained from operando SAXS profiles using representative structure modeling for the different materials and operating conditions.
KW - Polymer electrolyte fuel cell
KW - Catalyst layer saturation
KW - Microporous layer saturation
KW - Membrane hydration
KW - Small and wide-angle scattering
KW - MOUSE
KW - SAXS
KW - X-ray scattering
KW - Energy storage materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656691
DO - https://doi.org/10.1021/acsami.5c22540
SN - 1944-8244
SP - 1
EP - 17
PB - American Chemical Society (ACS)
AN - OPUS4-65669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charlesworth, M.
A1 - Lampronti, G.
A1 - Belenguer, Ana M.
A1 - Day, S.
A1 - Saunders, L.
A1 - Connolly, E.
A1 - Midgley, P.
A1 - Michalchuk, Adam A. L.
T1 - Influence of Liquid on Crystallite Size Evolution During Ball Milling
N2 - Liquid assisted grinding (LAG) is a commonly used mechanochemical procedure, especially for polymorphic conversions. However, it is not understood what effect liquid additives actually play in driving mechanochemical polymorphic conversions, precluding our ability to control solid form transformations under mechanochemical conditions. We here present a time-resolved in situ (TRIS) synchrotron powder Xray diffraction (PXRD) monitoring strategy that can track, with few nm resolution, the evolution of crystalline size under liquid assisted ball milling conditions. We apply this method to investigate the influence of liquid additives on the polymorphic conversion of the 1:1 co-crystal of theophylline and benzamide, with particular focus on the role that crystallite size plays in driving ball milling induced polymorphic transformations. We find that the crystallite sizes achieved by ball milling are highly sensitive to the amount of liquid added to the reaction mixture. Liquid additives generally lead to larger crystallite sizes as compared with neat grinding protocol, with our findings indicating that crystallite size reduction is not the main factor that causes polymorph conversion under liquid assisted grinding conditions. The data presented clearly indicates the presence of an induction period before phase transformation begins with a minimum value in the crystallite size of the starting polymorph indicating the end of that induction period.
KW - Ball milling
KW - In situ diffraction
KW - Phase transformation
KW - Liquid assisted grinding
KW - Crystallite size
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656783
DO - https://doi.org/10.1021/acs.cgd.5c01662
SN - 1528-7483
SP - 1
EP - 7
PB - American Chemical Society (ACS)
AN - OPUS4-65678
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharek, Vera M.
A1 - Traub, Heike
A1 - Meermann, Björn
T1 - A direct solid sampling approach for fluorine determination via ETV/ICP-QQQ-MS
N2 - Organic fluorine sum parameters are used to detect F-containing pollutants, e.g., per- and polyfluoroalkyl substances (PFASs), in the environment, within materials, or for monitoring technical processess, e.g., thermal decomposition of PFAS during municipal waste incineration. However, established approaches determining the extractable organic and adsorbable organic fluorine content (EOC and AOC) require laborious and error-prone sample preparation. We report a solid sampling-electrothermal vaporization (ETV) method for direct fluorine measurement based on the formation of [138Ba19F]+ with an inductively coupled plasma-triple quadrupole-mass spectrometer (ICP-QQQ-MS). Method development involved the instrumental setup for Ba introduction and fluorine-specific tuning of lens and collision-reaction cell (CRC) parameters. An inorganic fluorine fraction was detected in a cyclonic dust sample from a municipal waste incineration plant as a peak above a broad background signal. The content was estimated through standard addition using a NaF solution to 2300 mgg−1. With a limit of detection (LOD) of 130 mg g−1, which was below the reported value for an electrothermal vaporization/inductively coupled plasma-mass spectrometry (ETV/ICP-MS) approach, acquiring [19F]+. The method's potential for fractionation analysis was demonstrated by analyzing polytetrafluoroethylene (PTFE) powder.
KW - PFAS
KW - ETV/ICP-QQQ-MS
KW - Solid sampling
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656766
DO - https://doi.org/10.1039/d6ja00014b
SN - 0267-9477
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65676
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Krenzer, Julius
A1 - Petrov, Eugene P.
A1 - Biesen, Lukas
A1 - Vasylyeva, Vera
A1 - Merzenich, Sarah
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Aroyl-S,N-ketene acetal-triarylamine bichromophores – intramolecular energy transfer and dual emission upon induced aggregation and encapsulation
N2 - Aroyl-S,N-ketene acetal-based bichromophores are synthesized by a catalytic aryl amination and their photophysics are studied in the solid state, in ethanol–water mixtures inducing aggregation, and after encapsulation in polystyrene nanoparticles. The dye substitution pattern controls aggregation-induced emission and intramolecular energy transfer efficiency, resulting in single-band or dual fluorescence and a strong increase in fluorescence quantum yield upon particle encapsulation.
KW - Fluorescence
KW - Dye
KW - Aggregation
KW - Photophysics
KW - Enhancement
KW - White light emission
KW - Energy transfer
KW - Quantum yield
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656700
DO - https://doi.org/10.1039/d5ra09361a
SN - 2046-2069
VL - 16
IS - 11
SP - 10255
EP - 10260
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jesus, Vinicius D.
A1 - Merizio, Leonnam G.
A1 - Galleani, Gustavo
A1 - Raffy, Guillaume
A1 - Carpentier, Mathis
A1 - Petit, Yannick
A1 - Cardinal, Thierry
A1 - de Camargo, Andrea S. S.
T1 - Energy transfer from Ag species to Nd 3+ in Ga–fluoride–phosphate glasses: near-infrared emission enhancement via controlled heat treatment and femtosecond laser inscription
N2 - Gallium fluoride–phosphate glasses are promising materials with wide optical transmission window, high volumetric density, and the ability to accommodate high concentrations of rare earth dopant ions within a tailored fluoride-rich coordination environment, resulting in high emission cross sections. In this work, the compositional system 25Ga(PO3)3–20ZnF2–30BaF2–(25–x–y)SrF2–xAgNO3–yNdF3 (x = 0–10 mol%, y = 0 or 1 mol%) was studied to understand how silver species affect the near-infrared (NIR) emission of Nd3+ ions, when the glasses are subjected to controlled heat treatment and to femtosecond direct laser writing (DLW). The glasses were obtained via the melt-quenching technique and characterized by DSC, XRD, UV-Vis-NIR absorption, and PL spectroscopy. The as-prepared glasses show broad UV-Vis excitation and emission bands arising from the coexistence of Ag+ ions and ionic Ag pairs. In samples with 10 mol% Ag+, brownish coloration and modified emission profiles indicated Ag nanoparticle formation at the surface. Heat treatment promoted the conversion of isolated Ag+ into ionic pairs, producing broadband emissions tunable by excitation wavelength and Ag+ concentration. In co-doped samples, Nd3+ introduced absorption dips in the Ag-related UV-Vis bands, consistent with energy transfer, which was further confirmed by shortened Ag excited-state lifetimes and increased Nd3+ NIR emission under UVVis excitation. In order to control the spatial distribution and size of Ag aggregates (nanoclusters, NCs) and to increase the energy transfer efficiency to Nd3+, femtosecond direct laser writing (DLW) was employed to co-doped glasses with 3 and 5 mol% Ag+. This approach enabled three-dimensional localized growth of Ag NCs with sub-micron spatial control. In the laser processed regions, the NIR emissions of Nd3+ at 900 and 1060 nm were significantly enhanced, clearly evidencing enhanced energy transfer from the localized laserinduced Ag-NCs to the Nd3+ ions. These findings suggest the possibility of tailoring high optical contrast near-IR emissions in glasses, enabling progress in advanced photonic applications.
KW - Neodymium
KW - Silver
KW - Fluoride phosphate glasses
KW - Direct laser writing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656888
DO - https://doi.org/10.1039/d5ma01430a
SN - 2633-5409
SP - 1
EP - 14
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittrich, Tim
A1 - Peters, Simon
A1 - Meschke, Günther
A1 - Weise, Frank
A1 - Stelzner, Ludwig
T1 - Thermally induced moisture transport in concrete with different types of blended Portland cement studied by 1H-NMR relaxometry
N2 - Clinker-reduced cements are gaining in popularity as part of efforts to lower the construction industry’s CO2 footprint. Past studies showed that utilization of these cements negatively influences the fire-induced spalling behavior of concrete, which is highly influenced by thermohydraulic damage mechanisms. Therefore, thermally induced moisture transport in normal strength concretes made with different types of blended cements (CEM I, CEM II/A-LL, CEM III/A and CEM II/B-Q) was investigated by means of 1H-NMR relaxometry in combination with supportive side investigations concerning permeability and porosity. In addition, a numerical model was used to analyze in-situ moisture development during high temperature exposure. The results show that the cement type influences both initial moisture content and pore size-specific moisture distribution. This was primarily reflected in an increased water content in CEM III/A and CEM II/B-Q concretes as well as a comparable high gel pore water fraction in CEM II/B-Q concrete before heating. After heating, a similar degree of pore coarsening from gel to capillary pore was observed in all samples. Although the measurements were only conducted after, not during, high temperature exposure, the depth of the drying front and the extent of the moisture clog could be determined. With the additional numerical analysis, it can be assumed that during high temperature load, the drying front is less advanced and the moisture clog even more pronounced. In conclusion, it can be stated that the increased spalling susceptibility in blended cement concrete is caused by the lower initial permeability and increased moisture content.
KW - Fire concrete spalling
KW - Thermally induced moisture transport
KW - Blended cements
KW - 1H-NMR
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656846
DO - https://doi.org/10.1617/s11527-026-03025-4
SN - 1359-5997
VL - 59
IS - 3
SP - 1
EP - 20
PB - Springer Science and Business Media LLC
AN - OPUS4-65684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scharf-Wildenhain, R.
A1 - Engelking, Lorenz
A1 - Hälsig, A.
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
A1 - Hensel, J.
T1 - Influence of build‑up height on residual stresses in additive repair and modification using DED‑Arc with high‑strength filler metals
N2 - Directed energy deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between additive manufactured (AM) component and semifinished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead to component failure, especially for high-strength steels. Therefore, understanding and controlling residual stresses, when combining different base and feedstock materials, is critical to improve the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and feedstock material from commercial high-strength steels. Using a robot-assisted DED-system and a controlled short arc, AM welding experiments were carried out with close to the application parameters at working temperature (200 °C) and heat input (650 kJ/m). Five hybrid AM specimens (AM wall on upright structural steel plate) were produced using a one bead per layer strategy and selected AM-wall heights between 15 and 300 mm. The influence of the AM build height on the longitudinal residual stress in the whole hybrid AM specimen (in welding direction) was analyzed and discussed. All experiments exhibit comparable stress distributions in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the building height. The height significantly influences the residual stress distribution of the deposited AM-component. Tensile residual stresses with a maximum range between 300and 400 MPa were always found in the last approx. 18 component layers (upper 40 mm). This is due to restraint of the shrinking of the top layers by the layers below. The lower layers show homogeneous residual stress distributions characterized by low compressive stresses due to the process-related tempering during the deposition of each layer on top of each other. As a result, the significant difference between the various AM build-up heights of the hybrid AM specimens is the extent (or height) of this tempered zone with low compressive stresses. These correlations contribute to the understanding of residual stress development with increasing structure height or ratio of component heights of substrate semi-finished product and AM component in hybrid additive manufacturing.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genoa, Italy
DA - 22.06.2025
KW - DED-Arc
KW - Residual stress
KW - Heat control
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656793
DO - https://doi.org/10.1007/s40194-026-02417-y
SN - 1878-6669
SP - 1
EP - 12
PB - Spriner
AN - OPUS4-65679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roß, Marcel
A1 - Severin, Stefanie
A1 - Hildebrandt, Jana
A1 - Erdmann, Kerstin
A1 - Miaskiewicz, Aleksandra
A1 - Škorjanc, Viktor
A1 - Bernardes de Araujo, Wander Max
A1 - Leyden, Matthew
A1 - Korte, Lars
A1 - Seeger, Stefan
A1 - Dallmann, André
A1 - Albrecht, Steve
T1 - Compositional Analysis of Metal Halide Perovskites: Insight into the Coevaporation Process via Nuclear Magnetic Resonance and X-ray Fluorescence Spectroscopy
N2 - Lead halide perovskites have emerged as a highly promising class of materials for solar cells. Nevertheless, suitable procedures to analyze the exact composition of the perovskite films are rare and are not generally applicable. Here we show a simple and fast method to determine the absolute composition of mixed metal halide perovskites through a combination of nuclear magnetic resonance and total reflection X-ray fluorescence spectroscopy. The method is validated on powder mixtures and applied to thin film samples prepared by coevaporation of formamidinium iodide (FAI), CsI, PbI2 and PbBr2, allowing correlation between film composition and solar cell performance. We show that the rates of the individual precursors do not always translate linearly into film composition and that the preparation of the hole transport layer MeO-2PACz strongly influences the incorporation of FAI. Our work highlights the importance of compositional analysis and demonstrates how the developed method provides new insights into the complex coevaporation process in perovskite solar cells.
KW - e‑ray Fluorescence Spectroscopy
KW - Metal Halide Perovskites
KW - CoevaporationP rocess
KW - Nuclear Magnetic Resonance
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656932
DO - https://doi.org/10.1021/acsenergylett.5c03689
SN - 2380-8195
VL - 11
IS - 2
SP - 1935
EP - 1943
PB - American Chemical Society (ACS)
AN - OPUS4-65693
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markötter, Henning
A1 - Sintschuk, Michael
A1 - Bruno, Giovanni
T1 - X-ray computed tomography scanning schemes and reconstruction capabilities at the BAMline (BESSY II)
N2 - The BAMline at the BESSY II synchrotron (Berlin, Germany) is a multipurpose beamline that is used for computed tomography, among other techniques. For more than 20 years it has been used in various scientific fields to access and analyze internal structural features such as porosity, cracks or delamination. The general trend of tomographic X-ray imaging is moving towards in situ and operando studies to access the above-mentioned features under the most realistic conditions. This article presents the X-ray computed tomography (XCT) capabilities and the software suite, such as live reconstruction available to imaging users. Direct XCT reconstruction plays an important role in the quality control of the performed experiments and is particularly crucial for in situ and operando experiments. The BAMline now offers a sequence-based step-scan XCT that enables preview reconstruction during the scan to gain early insight into the scanned sample even while the scan is in progress. In addition, the sequence-based scheme includes lateral shifts, thereby mitigating ring artifacts and improving image quality. Finally, since XCT scan parameters, such as sample–detector distance and beam energy, are of utmost importance, we devised calculation software allowing control of monochromators to set the desired beam spectrum.
KW - Synchrotron X-ray imaging
KW - Computed tomography
KW - Preview reconstruction
KW - CT scan scheme
KW - Software workflow
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655792
DO - https://doi.org/10.1107/S1600577526001177
SN - 1600-5775
VL - 33
SP - 543
EP - 550
AN - OPUS4-65579
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Petitdemange, Eliot
A1 - Zhu, Jinjie
A1 - Pedersen, Angus
A1 - Parker, Joseph
A1 - Balaghi, Esmael
A1 - Li, Shaohua
A1 - Favero, Silvia
A1 - Ignacio Martínez, José
A1 - Haigh, Sarah
A1 - Titirici, Maria-Magdalena
A1 - Fischer, Anna
A1 - Barrio, Jesús
T1 - High-Yield Synthesis of Fe-NC Electrocatalysts Using Mg2+ Templating and Schiff-Base Porous Organic Polymers
N2 - The decoupled synthesis of Fe-NC single-site electrocatalysts mediated by Lewis acids enables high active site density and utilization. However, current approaches often rely on small organic molecules and suffer from low synthesis yields due to the high Lewis acid-to-precursor ratios required to achieve highly porous carbons. Here, a porous organic polymer (POP) based on 2,4,6-Triaminopyrimidine (TAP) is utilized as a carbon-nitrogen-based scaffold for the synthesis of Fe─NC electrocatalysts. By tuning the amounts of MgCl2 ·6H2O used both as porogen and active site templating agent, synthetic yields exceeding 45% are achieved, a significant improvement compared to the 6% yield from the molecular analogue and the highest reported forMg2+ templated systems. Subsequent low-temperature exchange with Fe leads to atomically dispersed FeNx, minimizing Fe aggregation. The resulting materials exhibit high specific surface areas (>1000 m2 g−1) with micro-, meso-, and macropores, which promote mass transport and active site accessibility. Compared to Fe─NC synthesized via direct pyrolysis of Fe-coordinated POP, the decoupled method enables significantly higher catalytic activity in both alkaline and acidic media, and delivers 1 A cm−2 at 0.687 ± 0.004 VRHE in an alkaline gas diffusion electrode, highlighting its potential for practical oxygen reduction devices.
KW - Porous Organic Polymers
KW - Single Atom
KW - Oxygen reduction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652618
DO - https://doi.org/10.1002/adfm.202518944
SN - 1616-3028
SP - 1
EP - 15
PB - Wiley-VCH GmbH
AN - OPUS4-65261
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trambitski, Yahor
A1 - Kizinievič, Olga
A1 - Kizinievič, Viktor
A1 - Pavasaryte, Lina
T1 - Revealing the Structural Transformation of Biopolymer-Modified Clay Materials Through Microtomography and Hygroscopic Analysis
N2 - This study focuses on the structural assessment of unfired clay materials (UCM) treated with different biopolymers using microtomography (microCT) and hygroscopic analysis. It addresses a significant research gap, as the analysis of hygroscopic properties in biopolymer-modified clays remains limited in the literature, while microCT investigations of such materials have been scarcely explored. The clay materials were modified using aqueous gelled biopolymer solutions of starch, alginate, and chitosan, each prepared under processing conditions adapted to their chemical characteristics and solubility: starch was dissolved in hot water, alginate in cold water, and chitosan in a slight acid solution. Moisture adsorption of the clay-biopolymer materials (CBM) increased up to 32.2%, as observed in the CBM, modified with a 7.5% alginate-based solution. Sorption hysteresis analysis revealed an increase in the hysteresis rate from 0.30% to 0.76–1.01% in CBMs, indicating that biopolymer modification enhanced the structural complexity of the clay matrix and promoted additional molecular interactions with water molecules within the CBM. MicroCT results demonstrated that within the CBM, biopolymers can function either as surface-coating agents (starch and alginate) or as organic clusters within the clay structure (chitosan). The obtained results highlight that biopolymer incorporation significantly enhances the hygroscopic buffering capacity of clay materials, offering a pathway toward sustainable building composites that can be applied in humidity-regulating finishes, eco-friendly construction blocks, and heritage conservation, where both moisture control and structural cohesion are essential.
KW - Unfired clay material
KW - Micro computed tomography
KW - Clay-biopolymer material
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656872
DO - https://doi.org/10.1007/s40684-026-00865-x
SN - 2288-6206
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-65687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Witte, Julien
A1 - Treutler, Kai
A1 - Schroepfer, Dirk
A1 - Kannengiesser, Thomas
A1 - Wesling, Volker
T1 - Influence of microstructure on the machinability and surface integrity of additively manufactured iron aluminides
N2 - The increasing global focus on energy and resource efficiency has stimulated a growing interest in additive manufacturing. AM offers economic advantages and enables an efficient use of materials. However, AM components often require subsequent mechanical post-processing, such as machining (e.g., milling), to achieve the final contours or surfaces. This is a particular challenge due to the heterogeneous and anisotropic nature of AM structures, which affect machining and the resulting component properties. High-performance materials such as iron aluminide represent a promising alternative to conventional high-temperature materials with a significant economic advantage. However, the strength and hardness properties, which are advantageous for applications in highly stressed lightweight components, pose a challenge for economical machining in addition to the AM microstructure properties. The difficult-to-cut material causes accelerated tool wear and insufficient surface quality. This study shows that crack-free additive manufacturing of the three-component system of iron-nickel-aluminum is possible, and advantages in terms of machinability compared to FeAl-AM components are achieved. The more homogeneous microstructure leads to a reduction in cutting forces, with positive effects on the machinability and optimized surface integrity. Ultrasonic assisted milling (USAM) offers great potential to address the major challenges posed by difficult-to-cut materials and additively manufactured weld structures. Therefore, this study focuses on assessing the transferability of previous positive results by USAM to the selected iron aluminide alloys. The machinability of the aluminides is analyzed by varying significant influencing variables in finish milling experiments and evaluated in terms of the loads on the tool and the resulting surface integrity.
KW - Iron aluminide
KW - Additive manufacturing
KW - Machinability
KW - Surface integrity
KW - Ultrasonic-assisted milling process
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656993
DO - https://doi.org/10.1007/s40194-026-02382-6
SN - 0043-2288
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65699
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tannenberg, Robert
A1 - Tscheuschner, Georg
A1 - Raab, Christopher
A1 - Flemig, Sabine
A1 - Döring, Sarah
A1 - Ponader, Marco
A1 - Thurmann, Melinda
A1 - Paul, Martin
A1 - Weller, Michael G.
T1 - Simplified Sample Preparation and Lateral Flow Immunoassay for the Detection of Plant Viruses
N2 - Lateral flow immunoassays (LFAs) are widely used for on-site testing; however, their use for the rapid detection of plant viruses in the field is often limited by inconvenient sample preparation. Here, we present a new sampling method and a simplified dipstick LFA format for the detection and monitoring of cowpea chlorotic mottle virus (CCMV) as a model plant pathogen. The assay employs a monoclonal mouse antibody for capture and a poly-clonal rabbit antibody conjugated to 80 nm gold nanoparticles for detection. Conventional sample and conjugate pads are omitted, allowing the test strips to be dipped directly into wells containing plant extract and antibody–gold conjugate. No plastic casing was required, which could lead to a reduction in waste. It was shown that CCMV concentrations as low as 3.5 µg/L or 350 pg per sample could be reliably detected in 15 min. Specificity tests confirmed that other plant viruses, cowpea mosaic virus (CPMV) and tobacco mosaic virus (TMV), did not produce false-positive results. In addition, we describe a new method for on-site sampling using a manual punch and a syringe equipped with a frit. This step combines grinding the sample, extraction, filtration, and reconstitution and mixing of the antibody-gold conjugate, enabling the analysis of punched leaf disks without laboratory equipment. When applied to CCMV-infected cowpea plants, the assay revealed systemic infection before visual symptoms became apparent. This work demonstrates that simplified LFAs combined with innovative sampling techniques can provide sensitive, specific, and rapid diagnostics for crop monitoring and support early intervention strategies in agriculture.
N2 - Lateral-Flow-Immunoassays (LFAs) werden häufig für Vor-Ort-Tests eingesetzt; ihr Einsatz zum schnellen Nachweis von Pflanzenviren im Feld wird jedoch oft durch eine umständliche Probenvorbereitung eingeschränkt. Hier stellen wir eine neue Probenahmemethode und ein vereinfachtes Dipstick-LFA-Format zum Nachweis und zur Überwachung des Cowpea Chlorotic Mottle Virus (CCMV) als Modellpflanzenpathogen vor. Der Test verwendet einen monoklonalen Maus-Antikörper zur Bindung und einen polyklonalen Kaninchen-Antikörper, der an 80-nm-Goldnanopartikel konjugiert ist, zum Nachweis. Herkömmliche Proben- und Konjugatpads entfallen, sodass die Teststreifen direkt in Vertiefungen getaucht werden können, die Pflanzenextrakt und das Antikörper-Gold-Konjugat enthalten. Es ist keine Kunststoffhülle erforderlich, was zu einer Reduzierung des Abfallaufkommens führen könnte. Es zeigte sich, dass CCMV-Konzentrationen von nur 3,5 µg/L oder 350 pg pro Probe innerhalb von 15 Minuten zuverlässig nachgewiesen werden konnten. Spezifitätstests bestätigten, dass andere Pflanzenviren, das Cowpea Mosaic Virus (CPMV) und das Tobacco Mosaic Virus (TMV), keine falsch-positiven Ergebnisse lieferten. Darüber hinaus beschreiben wir eine neue Methode zur Probenahme vor Ort unter Verwendung eines manuellen Lochers und einer mit einer Fritte ausgestatteten Spritze. Dieser Schritt kombiniert das Zerkleinern der Probe, die Extraktion, die Filtration sowie die Rekonstitution und das Mischen des Antikörper-Gold-Konjugats und ermöglicht so die Analyse der ausgestanzten Blattscheiben ohne Laborausrüstung. Bei der Anwendung an mit CCMV infizierten Augenbohnenpflanzen zeigte der Assay eine systemische Infektion, bevor visuelle Symptome erkennbar wurden. Diese Arbeit zeigt, dass vereinfachte LFAs in Kombination mit innovativen Probenahmetechniken eine sensitive, spezifische und schnelle Diagnostik für die Pflanzenüberwachung bieten und Strategien zur frühzeitigen Intervention in der Landwirtschaft unterstützen können.
KW - Point-of-care diagnostics
KW - Dipstick immunoassay
KW - Pre-symptomatic detection
KW - Precision agriculture
KW - Integrated pest management
KW - Crop health monitoring
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657039
DO - https://doi.org/10.3390/bios16020100
SN - 2079-6374
VL - 16
IS - 2
SP - 1
EP - 16
PB - MDPI AG
CY - Basle, Switzerland
AN - OPUS4-65703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fayis Kalady, Mohammed
A1 - Schultz, Johannes
A1 - Weinel, Kristina
A1 - Wolf, Daniel
A1 - Lubk, Axel
T1 - Geometry-dependent localization of surface plasmons on random gold nanoparticle assemblies
N2 - Assemblies of plasmonic nanoparticles (NPs) support hybridized modes of localized surface plasmons (LSPs), which delocalize in geometrically well-ordered arrangements. Here, the hybridization behavior of LSPs in geometrically completely disordered two-dimensional arrangements of Au NPs fabricated by an e-beam synthesis method is studied. Employing electron energy loss spectroscopy in a scanning transmission electron microscope and numerical simulations, the disorder-driven spatial and spectral localization of the coupled LSP modes that depends on the NP thickness is revealed. Below a NP thickness of 0.4 nm, localization increases toward higher hybridized LSP mode energies. In comparison, above 10 nm thickness, a decrease of localization toward higher mode energies is observed. In the intermediate thickness regime, a transition of the energy dependence of the localization between the two limiting cases, exhibiting a mode energy with minimal localization, is observed. It is shown that this behavior is mainly driven by the energy and thickness dependence of the polarizability of the individual NPs.
KW - Gold Nanoparticles
KW - Surface plasmons
KW - Electron enerdy loss spectroscopy (EELS)
KW - scanning transmission electron microscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647230
DO - https://doi.org/10.1103/44nk-6bp2
SN - 2643-1564
VL - 7
IS - 043053
EP - 4
PB - American Physical Society
AN - OPUS4-64723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Henning, Thorsten
A1 - Goerdeler, Cornelius
A1 - El-Khatib, Ahmed H.
A1 - Meyer, Klas
A1 - Bruer, Gustav G.
A1 - Abraham, Klaus
A1 - Monien, Bernhard
T1 - Characterization and quantitation of urinary metabolites of 3-monochloropropane-1,2-diol (3-MCPD) in rats
N2 - Fatty acid esters of 3-monochloropropane-1,2-diol (3-MCPD) are heat-induced contaminants formed from fats and sodium chloride. The mode of action for the 3-MCPD mediated induction of renal tubule neoplasms in rats is still unclear, which is in part due to lacking metabolism data. In the current study, urinary metabolites were identified by one- and two-dimensional 13C nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry following oral administration of 3-MCPD or [13C3]3-MCPD in rats. In addition to 3-MCPD itself, nine metabolites were identified. Four of those, N-acetyl-S-(2,3-dihydroxypropyl)cysteine (DHPMA), 3-MCPD sulfate, β-chlorolactic acid (β-ClLA) and oxalic acid have been reported before. Five novel metabolites in rat urine were thiodiglycolic acid (TDGA), thionyldiglycolic acid (TNDGA), 3-MCPD glucuronide (at least three isomers), 3-carboxy-2-hydroxypropyl mercapturic acid (CHPMA), and 3-(S-carboxymethyl)mercaptolactic acid (CMMLA). Only three metabolites were excreted at mean dose ratios > 1% (after treatment with 50 mg 3-MCPD/kg body weight in male and female rats), i.e. 3-MCPD (7.3%, 9.7%), DHPMA (3.5%, 1.7%) and TDGA (1.1%, 4.0%). The overall mean dose excretion in urine samples (males: 12.2%, females: 16.3%) supported hypotheses on formation of conjugates/adducts of reactive metabolites and the possibility that dechlorination leads to suitable building blocks for amino acid and fatty acid synthesis. The identification of TDGA indicated the interim formation 2-chloroacetaldehyde, previously identified to mediate specific nephrotoxic effects of the cytostatic ifosfamide in rats.
KW - 3-Monochloropropane-1,2-diol
KW - 3-MCPD
KW - Metabolism
KW - Urine
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657230
DO - https://doi.org/10.1007/s00204-026-04318-x
SP - 1
EP - 17
PB - Springer-Verlag GmbH
CY - Heidelberg
AN - OPUS4-65723
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Döring, Sarah
A1 - Wulfes, Birte S.
A1 - Atanasova, Aleksandra
A1 - Jaeger, Carsten
A1 - Walzel, Leopold
A1 - Tscheuschner, Georg
A1 - Flemig, Sabine
A1 - Gawlitza, Kornelia
A1 - Feldmann, Ines
A1 - Konthur, Zoltán
A1 - Weller, Michael G.
T1 - Corundum Particles as Trypsin Carrier for Efficient Protein Digestion
N2 - Reusable enzyme carriers are valuable for proteomic workflows, yet many supports are expensive or lack robustness. This study describes the covalent immobilization of recombinant trypsin on micrometer-sized corundum particles and assesses their performance in protein digestion and antibody analysis. The corundum surface was cleaned with potassium hydroxide, silanized with 3-aminopropyltriethoxysilane and activated with glutaraldehyde. Recombinant trypsin was then attached, and the resulting imines were reduced with sodium cyanoborohydride. Aromatic amino acid analysis (AAAA) estimated an enzyme loading of approximately 1 µg/mg. Non-specific adsorption of human plasma proteins was suppressed by blocking residual aldehydes with a Tris-glycine-lysine buffer. Compared with free trypsin, immobilization shifted the temperature optimum from 50 to 60 °C and greatly improved stability in 1 M guanidinium hydrochloride. Activity remained above 80% across several reuse cycles, and storage at 4 °C preserved functionality for weeks. When applied to digesting the NISTmAb, immobilized trypsin provided peptide yields and sequence coverage comparable to soluble enzyme and outperformed it at elevated temperatures. MALDI-TOF MS analysis of Herceptin digests yielded fingerprint spectra that correctly identified the antibody and achieved 60% sequence coverage. The combination of low cost, robustness and analytical performance makes corundum-immobilized trypsin an attractive option for research and routine proteomic workflows.
N2 - Wiederverwendbare Enzymcarrier sind für proteomische Arbeitsabläufe von großem Wert, doch viele Trägermaterialien sind teuer oder nicht robust genug. Diese Studie beschreibt die kovalente Immobilisierung von rekombinantem Trypsin auf mikrometergroßen Korundpartikeln und bewertet deren Leistungsfähigkeit beim Proteinverdau und der Antikörperanalyse. Die Korundoberfläche wurde mit Kaliumhydroxid gereinigt, mit 3-Aminopropyltriethoxysilan silanisiert und mit Glutaraldehyd aktiviert. Anschließend wurde rekombinantes Trypsin gebunden, und die entstandenen Imine wurden mit Natriumcyanoborhydrid reduziert. Die aromatische Aminosäureanalyse (AAAA) ergab eine geschätzte Enzymbeladung von etwa 1 µg/mg. Die unspezifische Adsorption von menschlichen Plasmaproteinen wurde durch Blockierung der restlichen Aldehyde mit einem Tris-Glycin-Lysin-Puffer unterdrückt. Im Vergleich zu freiem Trypsin verschob die Immobilisierung das Temperaturoptimum von 50 auf 60 °C und verbesserte die Stabilität in 1 M Guanidiniumhydrochlorid erheblich. Die Aktivität blieb über mehrere Wiederverwendungszyklen hinweg bei über 80 %, und die Lagerung bei 4 °C bewahrte die Funktionalität über Wochen hinweg. Beim Verdau des NISTmAb lieferte das immobilisierte Trypsin Peptidausbeuten und Sequenzabdeckungen, die mit denen des löslichen Enzyms vergleichbar waren, und übertraf dieses bei erhöhten Temperaturen. Die MALDI-TOF-MS-Analyse von Herceptin-Verdauen ergab Fingerabdruck-Spektren, die den Antikörper korrekt identifizierten und eine Sequenzabdeckung von 60 % erreichten. Die Kombination aus niedrigen Kosten, Robustheit und analytischer Leistungsfähigkeit macht auf Korund immobilisiertes Trypsin zu einer attraktiven Option für die Forschung und routinemäßige proteomische Arbeitsabläufe.
KW - Bottom-up proteomics
KW - Solid-phase digestion
KW - Biopharmaceutical analysis
KW - Peptide mapping
KW - Non-specific binding
KW - amino acid analysis
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657021
DO - https://doi.org/10.3390/biotech15010002
SN - 2673-6284
VL - 15
IS - 1
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-65702
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Schröder, Nina
A1 - Schröpfer, Dirk
A1 - Kannengießer, Thomas
T1 - Hydrogen-assisted cracking in GMA welding of high-strength structural steel - A new look into this issue at narrow groove
N2 - Modern arc processes, such as the modified spray arc (Mod. SA), have been developed for gas metal arc welding of high-strength structural steels with which even narrow weld seams can be welded. High-strength joints are subjected to increasingly stringent requirements in terms of welding processing and the resulting component performance. In the present work, this challenge is to be met by clarifying the influences on hydrogen-assisted cracking (HAC) in a high-strength structural steel S960QL. Adapted samples analogous to the self-restraint TEKKEN test are used and analyzed with respect to crack formation, microstructure, diffusible hydrogen concentration and residual stresses. The variation of the seam opening angle of the test seams is between 30° and 60°. To prevent HAC, the effectiveness of a dehydrogenation heat treatment (DHT) from the welding heat is investigated.
As a result, the weld metals produced at reduced weld opening angle show slightly higher hydrogen concentrations on average. In addition, increased micro- as well as macro-crack formation can be observed on these weld metal samples. On all samples without DHT, cracks in the root notch occur due to HAC, which can be prevented by DHT immediately after welding.
KW - High-strength structural steel
KW - Gas metal arc welding
KW - Diffusible hydrogen
KW - Hydrogen-assisted cracking
KW - TEKKEN
KW - Residual stresses
KW - Weld metal cracking
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527260
DO - https://doi.org/10.3390/met11060904
VL - 11
IS - 6
SP - 1
EP - 18
PB - MDPI
CY - Basel
AN - OPUS4-52726
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Meyer, A.
A1 - Weidner, Steffen
T1 - High Tm Poly(l-lactide)s by Means of Bismuth Catalysts?
N2 - One series of BiSub-catalyzed ring-opening polymerizations (ROPs) is per-formed at 160 °C for 3 days with addition of difunctional cocatalysts to find out, if poly(l-lactide) crystallizes directly from the reaction mixture. An analogous series is performed with monofunctional cocatalysts. High Tm crystal-lites (Tm > 190 °C) are obtained from all bifunctional cocatalysts, but not from all monofunctional ones. It is shown by means of SAXS measurements that the high Tm values are mainly a consequence of a transesterification–homogenization process across the lamellar surfaces resulting in thickness and smoothing of the surfaces. An unusual enthalpy-driven modification of the molecular weight distribution is found for samples that have crystallized during the polymerization. A third series of ROPs is performed at 170 °C for 2 h followed by annealing at 120 °C (2 h) to induce crystallization. Complete transformation of the resulting low Tm crystallites (Tm < 180 °C) into the high Tm crystallites by annealing at 170 °C for 1 d is not achieved, despite variation of the cocatalyst.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystallization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522777
DO - https://doi.org/10.1002/macp.202100019
SN - 1022-1352
VL - 222
IS - 8
SP - 19
PB - Wiley
AN - OPUS4-52277
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About the Influence of (Non-)Solvents on the Ring Expansion Polymerization of l-Lactide and the Formation of Extended Ring Crystals
N2 - Ring-expansion polymerizations (REPs) catalyzed by two cyclic tin catalysts(2-stanna-1.3-dioxa-4,5,6,7-dibenzazepine [SnBiph] and
2,2-dibutyl-2-stanna-1,3-dithiolane [DSTL) are performed at 140 °C in bulk.
Small amounts (4 vol%) of chlorobenzene or other solvents are added to facilitate transesterification reactions (ring–ring equilibration) in the solid poly(l-lactide)s. In the mass range up to m/z 13 000 crystalline PLAs displaying a so-called saw-tooth pattern in the MALDI-TOF mass spectra are obtained indicating the formation of extended-ring crystals. The characteristics of extended-ring crystallites and folded-ring crystallites are discussed. Furthermore, extremely high melting temperatures (Tm’s up to 201.2 °C) and melting enthalpies (𝚫Hm’s up to 106 J g−1)) are found confirming that 𝚫Hmmax, the 𝚫Hm of a perfect crystal, is around or above 115 J g−1 in contrast to literature data.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Crystals
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565038
DO - https://doi.org/10.1002/macp.202200385
SN - 1022-1352
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-56503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Kricheldorf, H. R.
T1 - SnOct2-catalyzed ROPs of L-lactide initiated by acidic OH- compounds: Switching from ROP to polycondensation and cyclization
N2 - Ring-opening polymerizations (ROPs) of L-lactide are performed in bulk at 130°C with tin(II) 2-ethylhexanoate as catalyst and various phenols of differentacidity as initiators. Crystalline polylactides having phenyl ester end groups are isolated, which are almost free of cyclics. The dispersities and molecular weights are higher than those obtained from alcohol-initiated ROPs under identical conditions. Polymerizations at 160°C yield higher molecular weights than expected from the monomer/initiator ratio and a considerable fraction of cycles. The fraction of cycles increases with higher reactivity of the ester end group indicating that the cycles are formed by end-to-end cyclization.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polymerization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-540250
DO - https://doi.org/10.1002/pol.20210823
SN - 2642-4150
VL - 60
IS - 5
SP - 785
EP - 793
PB - Wiley
AN - OPUS4-54025
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Musl, O.
A1 - Sulaeva, I.
A1 - Sumerskii, I.
A1 - Mahler, A.K.
A1 - Rosenau, T.
A1 - Falkenhagen, Jana
A1 - Potthast, A.
T1 - Mapping of the Hydrophobic Composition of Lignosulfonates
N2 - Lignosulfonates are industrial biorefinery products that are characterized by significant variability and heterogeneity in their structural composition. Typically, they exhibit high dispersities in molar mass (molar mass distribution-MMD) and in functionalities (functionality-type distribution - FTD), which crucially affect their material usage. In terms of FTD, state-of-the-art Lignin analytics still rely mainly on the determination of functional group contents, which are statistical averages with limited explanatory power. In contrast, our online hydrophobic interaction chromatography−size-exclusion chromatography 2D-LC approach combines the determination of both MMD and FTD in a single measurement to provide a comprehensive picture of the characteristic composition of industrial lignosulfonates information hitherto inaccessible by state-of-the-art lignin analytics. In this way, the complex inter - relationships between these two important structural parameters can be studied in an unprecedented manner. In this study, we reveal the considerable differences in terms of hydrophobic composition and its dispersity present in a range of different industrial lignosulfonates - data desperately needed in tailoring and refining of lignosulfonate composition for material usage.
KW - Lignosulfonates
KW - Amphiphilicity
KW - Hydrophobic interaction chromatography
KW - Two-dimensional chromatography (2D-LC)
KW - Charge-to-size-ratio
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538612
DO - https://doi.org/10.1021/acssuschemeng.1c06469
VL - 9
IS - 49
SP - 16786
EP - 16795
PB - ASC Publications
AN - OPUS4-53861
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Falkenhagen, Jana
T1 - Reversible Polycondensations outside the Jacobson-Stockmayer Theory and a New Concept of Reversible Polycondensations
N2 - L-Lactide was polymerized with tin(II)acetate, tin(II)2-ethyl hexanoate, diphenyltin dichloride and dibutyltin bis(pentafluorophenoxide) at 130 °C in bulk. When an alcohol was added as initiator, linear chains free of cycles were formed having a degree of polymerization (DP) according to the lactide/initiator (LA/In) ratio.
Analogous polymerizations in the absence of an initiator yielded high molar mass cyclic polylactides.
Quite similar results were obtained when ε-caprolactone was polymerized with or without initiator.
Several transesterification experiments were conducted at 130 °C, either with polylactide or poly(ε-caprolactone) indicating that several transesterification mechanisms are operating under conditions that do not include formation of cycles by back-biting. Furthermore, reversible polycondensations (revPOCs) with low or moderate conversions were found that did not involve any kind of cyclization. Therefore, These results demonstrate the existence of revPOCs, which do neither obey the theory of irreversible polycondensation as defined by Flory nor the hypothesis of revPOCs as defined by Jacobson and Stockmayer. A new concept encompassing any kind of revPOCs is formulated in the form of a “polycondensation triangle”.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polycondensation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530831
DO - https://doi.org/10.1039/d1py00704a
VL - 12
IS - 35
SP - 5003
EP - 5016
PB - Royal Society for Chemistry
AN - OPUS4-53083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Poly(L-lactide): Optimization of Melting Temperature and Melting Enthalpy
N2 - Twice recrystallized L-lactide was polymerized with a dozen of different tin or bismuth catalysts in bulk at 160°C for 24 h and was annealed at 150°C afterwards. In two cases Tm values above 197.0°C were obtained. The parameters causing a scattering of the DSC data were studied and discussed. The samples prepared with SnCl2, 2,2-dibutyl-2-stanna-1,3-ditholane (DSTL) or cyclic tin(II) bisphenyldioxide (SnBiph) were subject to annealing programs with variation of time and temperatures, revealing that the Tm´s did not increase. However, an increase of Hm was achieved with maximum values in the range of 93-96 J g-1 corresponding to crystallinities off around 90%. Further studies were performed with once recrystallized L-lactide. Again, those samples directly crystallized from the polymerization process showed the highest Tm values. These data were compared with the equilibrium Tm0 and Hm0 data calculated by several research groups for perfect crystallites. A Tm0 of 213+/-2°C and a Hm0 of 106 J g-1 show the best agreement with the experimental data. The consequences of annealing for the thickness growth of crystallites are discussed on the basis of SAXS measurements. Finally, a comparison of cyclic and linear poly L-lactide)s is discussed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Transesterification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538656
DO - https://doi.org/10.1039/D1MA00957E
SP - 1
EP - 10
PB - Royal Society for Chemistry
AN - OPUS4-53865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fink, Friedrich
A1 - Emmerling, Franziska
A1 - Falkenhagen, Jana
T1 - Identification and Classification of Technical Lignins by means of Principle Component Analysis and k-Nearest Neighbor Algorithm
N2 - The characterization of technical lignins is a key step for the efficient use and processing of this material into valuable chemicals and for quality control. In this study 31 lignin samples were prepared from different biomass sources (hardwood, softwood, straw, grass) and different pulping processes (sulfite, Kraft, organosolv). Each lignin was analysed by attenuated total reflectance Fourier transform infrared (ATR-FT-IR) spectroscopy. Statistical analysis of the ATR-FT-IR spectra by means of principal component analysis (PCA) showed significant differences between the lignins. Hence, the samples can be separated by PCA according to the original biomass. The differences observed in the ATR-FT-IR spectra result primarily from the relative ratios of the p-hydroxyphenyl, guaiacyl and syringyl units. Only limited influence of the pulping process is reflected by the spectral data. The spectra do not differ between samples processed by Kraft or organosolv processes. Lignosulfonates are clearly distinguishable by ATR-FT-IR from the other samples. For the classification a model was created using the k-nearest neighbor (k NN) algorithm. Different data pretreatment steps were compared for k=1…20. For validation purposes, a 5-fold cross-validation was chosen and the different quality criteria Accuracy (Acc), Error Rate (Err), Sensitivity (TPR) and specificity (TNR) were introduced. The optimized model for k=4 gives values for Acc = 98.9 %, Err = 1.1 %, TPR = 99.2 % and TNR = 99.6 %.
KW - Classification
KW - PCA
KW - K-nearest neighbor
KW - FT-IR
KW - Technical lignin
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-533855
DO - https://doi.org/10.1002/cmtd.202100028
VL - 1
IS - 8
SP - 350
EP - 396
PB - Wiley-VCH GmbH
AN - OPUS4-53385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - High Tm linear poly(L-lactide)s prepared via alcohol-initiated ROPs of L-lactide
N2 - Alcohol-initiated ROPs of L-lactide were performed in bulk at 160 °C for 72 h with variation of the catalyst or with variation of the initiator (aliphatic alcohols). Spontaneous crystallization was only observed when cyclic Sn(II) compounds were used as a catalyst. Regardless of initiator, high melting crystallites with melting temperatures (Tm) of 189–193 °C were obtained in almost all experiments with Sn(II) 2,2′-dioxybiphenyl (SnBiph) as catalyst, even when the time was shortened to 24 h. These HTm poly(lactide)s represent the thermodynamically most stable form of poly(L-lactide). Regardless of the reaction conditions, such high melting crystallites were never obtained when Sn(II) 2-ethylhexanoate (SnOct2) was used as catalyst. SAXS measurements evidenced that formation of HTm poly(L-lactide) involves growth of the crystallite thickness, but chemical modification of the crystallite surface (smoothing) seems to be of greater importance. A hypothesis, why the “surface smoothing” is more effective for crystallites of linear chains than for crystallites composed of cycles is discussed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-opening polymerization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524330
DO - https://doi.org/10.1039/d1ra01990b
VL - 11
IS - 23
SP - 14093
EP - 14102
PB - Royal Society of Chemistry
AN - OPUS4-52433
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - ROP of L-lactide and ε-caprolactone catalyzed by tin(ii) andtin(iv) acetates–switching from COOH terminated linear chains to cycles
N2 - The catalytic potential of tin(II)acetate, tin(IV)acetate, dibutyltin-bis-acetate and dioctyl tin-bis-acetate was compared based on polymerizations of L-lactide conducted in bulk at 160 or 130°C. With SnAc2 low-Lac/Cat ratios (15/1–50/1) were studied and linear chains having one acetate and one carboxyl end group almost free of cyclics were obtained. Higher monomer/catalyst ratios and lower temperatures favored formation of cycles that reached weight average molecular weights (Mw's) between 100,000 and 2,500,000. SnAc4 yielded mixtures of cycles and linear species under all reaction conditions. Dibutyltin- and dioctyl tin bis-acetate yielded cyclic polylactides under most reaction conditions with Mw's in the range of 20,000–80,000. Ring-opening polymerizations performed with ε-caprolactone showed similar trends, but the formation of COOH-terminated linear chains was significantly more favored compared to analogous experiments with lactide. The reactivity of the acetate catalysts decreased in the following order: SnAc2> SnAc4>Bu2SnAc2~Oct2SnAc2
KW - Polylactide
KW - MALDI-TOF MS
KW - Catalyst
KW - Ring-opening polymerization
KW - Tin acetates
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521923
DO - https://doi.org/10.1002/pol.20200866
VL - 59
IS - 5
SP - 439
EP - 450
PB - Wiley Online Library
AN - OPUS4-52192
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Scheliga, F.
A1 - Weidner, Steffen
T1 - What does conversion mean in polymer science?
N2 - The definition of the term “conversion” is discussed for a variety of polymer syntheses. It is demonstrated that in contrast to organic and inorganic chemistry several different definitions are needed in polymer science. The influence of increasing conversion on structure and topology of homo- and Copolymers is illustrated. Chain-growth polymerizations, such as radical polymerization or living anionic polymerizations of vinyl monomers, condensative chain polymerization, two and three-dimensional step-growth polymerizations, ring–ring or chain–chain equilibration and chemical modification of polymers are considered.
KW - Polymers
KW - Polymerization
KW - Conversion
KW - Polycondensation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523597
DO - https://doi.org/10.1002/macp.202100010
VL - 222
IS - 8
SP - 10
PB - Wiley VCH
AN - OPUS4-52359
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Falkenhagen, Jana
T1 - The role of transesterifications in reversible polycondensations and a reinvestigation of the Jacobson-Beckmann-Stockmayer experiments
N2 - The polycondensations of adipic acid and 1,10-decanediol catalyzed by toluene sulfonic acid (TSA) were reinvestigated using MALDI TOF mass spectrometry and NMR spectroscopy. Unexpected reactions of TSA were detected along with incomplete conversion of the monomers. Furthermore, transesterification reactions of end-capped poly(1,10-decanediol adipate) and end-capped poly(ε-caprolactone) catalyzed by TSA were studied. Despite the quite different (ionic) reaction mechanisms, it was found that for polycondensations performed in bulk intermolecular transesterification is more efficient than the intramolecular “back-biting”; this scenario was not considered in the Jacobson–Stockmayer theory of reversible polycondensations.
These results also confirm that the Jacobson–Stockmayer explanation of reversible polycondensations solely on the basis of ring chain equilibration is not only devoid of any experimental evidence, but also in contradiction to the results elaborated in this work.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polycondensation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543402
DO - https://doi.org/10.1039/d1py01679b
SN - 1759-9962
SP - 1
EP - 9
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-54340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Ring-Expansion Polymerization of 𝝐-Caprolactone, Glycolide, and l-lactide with a Spirocyclic Tin(IV) Catalyst Derived from or 2,2′-Dihydroxy-1,1′-Binaphthyl – New Results and a Revision
N2 - In contrast to other cyclic tin bisphenoxides, polymerizations of glycolide and l-lactide with the spirocyclic tin(IV) bis-1,1′-bisnapthoxide yield linear chains having a 1,1′-bisnapthol end group and no cycles. In the case of l-lactide, LA/Cat ratio and temperature are varied and at 160 °C or below, all polylactides mainly consist of even-numbered chains. A total predominance of even-numbered chains is also found for homopolymerization of glycolide, or the copolymerization of glycolide and l-lactide, when conducted <120 °C.
Linear chains having a bisnaphthol end group are again the main reaction products of ring-expansion polymerizations (REP) of 𝝐-caprolactone, but above 150 °C cycles are also formed.
KW - Polylactide
KW - MALDI-TOF MS
KW - Polymerization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541931
DO - https://doi.org/10.1002/macp.202100308
VL - 222
IS - 24
SP - 1
EP - 10
PB - Wiley VCH GmbH
AN - OPUS4-54193
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
T1 - H2O-Initiated Polymerization of L-Lactide
N2 - Water-initiated ring-opening polymerizations (ROPs) of L-lactide (LA) were performed in bulk at 140 °C, whereupon 11 different salts or complexes of low-toxic metal ions such as tin (II), Zn(II), Zr(IV), and Bi(III) were used as catalysts. Only four catalysts gave satisfactory results despite a long reaction time (24 h). The influence of the temperature was studied with tin (II) 2-ethylhexanoate (SnOct2), dibutyltin oxide (Bu2SnO), and zinc bis-acetylacetonate (Zn(acac)2) and zirconium acetylacetonate (Zr(acac)4). With SnOct2, Bu2SnO and Zr(acac)4 the time was varied at 140 °C to compare their reactivity. Furthermore, two series of ROPs were carried out with variation of the LA/H2O ratio to verify the control of the molecular weight by the monomer-initiator ratio. Bi- or tri-modal molecular weight distributions (MWD) were found for most of the ROPs and bimodal melting endotherms in the differential scanning calorimetry (DSC) heating traces. The thickness and dependence of the 3D packing of the crystallites were monitored by small-angle X-ray scattering (SAXS) measurements.
KW - MALDI-TOF MS
KW - Polylactide
KW - Ring-opening polymerization
KW - Crystallization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628761
DO - https://doi.org/10.1007/s10924-025-03565-w
SN - 1572-8919
VL - 33
IS - 6
SP - 2843
EP - 2857
PB - Springer Science and Business Media LLC
CY - New York, NY
AN - OPUS4-62876
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Scheliga, Felix
A1 - Kricheldorf, Hans R.
T1 - Polycondensation, Cyclization and Disproportionation of Solid Poly(L-lactide) Trifluoroethyl Esters and the Simultaneous Formation of Extended Chain Crystals and Extended Ring Crystals
N2 - Two poly(L-lactide)s (PLAs) with a degree of polymerization (DP) of 20 or 100 were prepared by trifluoroethanol-initiated ring-opening polymerization (ROP) catalyzed by tin(II) 2-ethyl hexanoate (SnOct2). These PLAs were annealed at 140 ◦C or at 160 ◦C in the presence of SnOct2, and the changes in topology and molecular weight distribution (MWD) were monitored by matrix-assisted laser desorption/ionization time-of flight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC). For the PLA with a DP 20, the main reaction was polycondensation combined with higher dispersities. In the case of the DP 100, PLA polycondensation was combined with disproportionation and the formation of a new MWD maximum around m/z 3500. In addition, extensive cyclization occurred, and the resulting cyclic PLAs crystallized separately from the linear chains in the form of extended ring crystals. These results also suggest that both extended chain and extended ring crystals posses the same crystal thickness as a result of thermodynamically controlled transesterification in the solid state.
KW - Polycondensation
KW - MALDI
KW - Polylactide
KW - Cyclization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616441
DO - https://doi.org/10.1016/j.polymer.2024.127800
VL - 315
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-61644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Falkenhagen, Jana
A1 - Dalgic, Mete-Sungur
A1 - Weidner, Steffen
T1 - Quantitative MALDI-TOF Mass Spectrometry of Star-Shaped Polylactides Based on Chromatographic Hyphenation
N2 - The end groups of three- and four-arm star-shaped polylactides (PLA) with trimethylolpropane and pentaerythritol core structures were functionalized with acetic acid. Reaction products with different degrees of functionalization were analyzed by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Additional gradient elution liquid adsorption chromatography (GELAC) measurements were performed to determine the degree of functionalization. This technique enabled clear separation and sufficient quantification of the formed species. These chromatographic data could be used inversely to quantify mass spectrometric results, which are usually biased by the unknown ionization probabilities of different polymer end group structures. Our results showed that, in this particular case, the peak intensity in the MALDITOF mass spectra can be used to semiquantitatively determine the degree of functionalization in incompletely functionalized multiarm PLA.
KW - Polylactides
KW - MALDI-TOF-MS
KW - Gradient elution liquid adsorption chromatography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625292
DO - https://doi.org/10.1021/jasms.4c00491
SN - 1879-1123
SP - 1
EP - 9
PB - American Chemical Society (ACS)
AN - OPUS4-62529
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Scheliga, Felix
T1 - Polycondensation of L-lactic acid: a deeper look into solid state polycondensation
N2 - L-Lactic acid (LA) was condensed in the presence of SnCl2 or 4-toluenesulfonic acid (TSA) at 140 °C, and chain growth without cyclization was observed. In addition, poly(L-lactic acid)s (PLAs) with a degree of polymerization (DP) of 25, 50 or 100 were prepared by water-initiated ring-opening polymerization (ROP). These PLAs were annealed in the solid state at 140 °C and 160 °C in the presence of tin(II) 2-ethylhexanoate (SnOct2, SnCl2 or TSA). The changes in the molar mass distribution and in the topology were characterized by means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry and size exclusion chromatography (SEC). With increasing time, fewer side reactions caused higher molar masses and increasing fractions of cyclic polylactides (cPLA) were obtained. Their “saw tooth” pattern in the MALDI-TOF mass spectra indicated the formation of extended ring crystallites in the solid state. TSA was the most active catalyst and caused fewer side reactions than SnCl2, which was the least reactive catalyst. Acetylation of the CH-OH end groups hindered polycondensation and prevented the formation of cPLAs. Reaction mechanisms will be discussed.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Polylaktide
KW - Solid state
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625271
DO - https://doi.org/10.1039/d4py01191k
SN - 1759-9962
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62527
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About alcohol-initiated polymerization of glycolide and separate crystallization of cyclic and linear polyglycolides
N2 - Alcohol-initiated polymerizations of glycolide (GL) catalyzed by tin(II) 2-ethylhexanoate (SnOct2) were carried out in bulk with variation of GA/In ratio, temperature and time. Due to a rather strong competition of cyclization polyglycolide (PGA) free of cycles were never obtained. When the cyclic catalysts 2,2-dibutal-2-stanna − 1,3-dithiolane (DSTL) or 2-stanna 1,3-dioxo-4,5,6,7 bibenzepane (SnBiph) were used in combination with 1,4-butanediol the influence of cyclization was even stronger. Furthermore, the degrees of polymerization were higher than the GA/alcohol ratio due to rapid polycondensation in the solid state. At 160 °C or below, the matrixassisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra indicated separate crystallization of low molar mass cyclic and linear PGAs from the same reaction mixture (also observed for poly(L-lactide)s).
KW - MALDI TOF MS
KW - Polyglycolide
KW - Ring opening polymerization
KW - Cyclization
KW - Crystallization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607282
DO - https://doi.org/10.1016/j.polymer.2024.127440
SN - 0032-3861
VL - 309
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-60728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Syntheses of cyclic polylactides and the problem of catenane formation
N2 - Cyclic poly(L-lactide)s (PLAs) were prepared in bulk either by ring-expansion polymerization (REP) or by ring-opening polymerization (ROP) with simultaneous polycondensation (ROPPOC). In contrast to REP the latter method involves formation of linear chains and thus, may involve formation of polydisperse catenanes that affect crystallization. The reprecipitated PLAs were annealed at 120 °C and compared with regard to melting temperature (Tm) and melting enthalpy (ΔHm). For similar molar masses the PLAs prepared by REP and ROPPOC had almost identical Tm's and crystallinities. Furthermore, the influence of REP and ROPPOC catalysts on the morphology of the virgin reaction products was compared.
KW - MALDI-TOF MS
KW - Catenane
KW - Polylactide
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625061
DO - https://doi.org/10.1039/d4ra08683j
VL - 15
IS - 5
SP - 3686
EP - 3692
PB - RSC
AN - OPUS4-62506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, A.
A1 - Anis, B.
A1 - Szymoniak, Paulina
A1 - Altmann, Korinna
A1 - Schönhals, Andreas
T1 - Graphene Oxide/Polyvinyl Alcohol–Formaldehyde Composite Loaded by Pb Ions: Structure and Electrochemical Performance
N2 - An immobilization of graphene oxide (GO) into a matrix of polyvinyl formaldehyde (PVF) foam as an eco-friendly, low cost, superior, and easily recovered sorbent of Pb ions from an aqueous solution is described. The relationships between the structure and electrochemical properties of PVF/GO composite with implanted Pb ions are discussed for the first time. The number of alcohol groups decreased by 41% and 63% for PVF/GO and the PVF/GO/Pb composite, respectively, compared to pure PVF. This means that chemical bonds are formed between the Pb ions and the PVF/GO composite based on the OH groups. This bond formation causes an increase in the Tg values attributed to the formation of a strong surface complexation between adjacent layers of PVF/GO composite. The conductivity increases by about 2.8 orders of magnitude compared to the values of the PVF/GO/Pb composite compared to the PVF. This means the presence of Pb ions is the main factor for enhancing the conductivity where the conduction mechanism is changed from ionic for PVF to electronic conduction for PVF/GO and PVF/GO/Pb.
KW - Graphene oxide
KW - Polyvinyl formaldehyde
KW - Lead ions
KW - Conductivity
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-549588
DO - https://doi.org/10.3390/polym14112303
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-54958
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Szymoniak, Paulina
A1 - Tavasolyzadeh, Zeynab
A1 - Sturm, Heinz
A1 - Topolniak, Ievgeniia
T1 - Multiphoton lithography of interpenetrating polymer networks for tailored microstructure thermal and micromechanical properties
N2 - Multiphoton lithography (MPL), an emerging truly 3D microfabrication technique, exhibits substantial potential in biomedical applications, including drug delivery and tissue engineering. Fabricated micro-objects are often expected to undergo shape morphing or bending of the entire structure or its parts. Furthermore, ensuring precise property tuning is detrimental to the realization of the functionality of MPL microstructures. Herein, novel MPL materials based on interpenetrating polymer networks (IPNs) are presented that effectively combine the advantages of acrylate and epoxy systems. IPNs with varying component ratios are investigated for their microfabrication performance and structural integrity with respect to thermal and micromechanical properties. A variety of high-resolution techniques is applied to comprehensively evaluate IPN properties at the bulk, micron, and segmental levels. This study shows that the MPL laser scanning velocity and power, photoinitiator content, and multi-step exposure can be used to tune the morphology and properties of the IPN. As a result, a library of 3D MPL IPN microstructures with high 3D structural stability and tailored thermal and micromechanical properties is achieved. New IPN microstructures with Young’s moduli of 3–4 MPa demonstrate high-to-fully elastic responses to deformations, making them promising for applications in morphable microsystems, soft micro-robotics, and cell engineering.
KW - Interpenetrating polymer network
KW - Multiphoton lithography
KW - Atomic force microscopy
KW - Intermodulation AFM
KW - Fast scanning calorimetry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600593
DO - https://doi.org/10.1002/smll.202310580
SN - 1613-6810
SP - 1
EP - 12
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-60059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Huang, J.
A1 - Szymoniak, Paulina
A1 - Bojdys, M. J.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Structure and molecular mobility of phosphinine-based covalent organic frameworks – glass transition of amorphous COFs
N2 - Two-dimensional covalent organic frameworks (COFs) based on phosphinine and thiophene building blocks have been synthesized with two different side groups. The materials are denoted as CPSF-MeO and CPSF-EtO where CxxF correspond to the covalent framework, whereas P and S are related to heteroatoms phosphorous and sulfur. MeO and EtO indicate the substituents, i.e. methoxy and ethoxy.
Their morphologies were studied by scanning electron microcopy and X-ray scattering. The absence of crystalline reflexes in the X-ray pattern reveal that both materials are amorphous and can be considered as glasses. Furthermore, N2 adsorption measurements indicate substantial Brunauer–Emmett–Teller (BET) surface area values pointing to the formation of three-dimensional pores by stacking of the aromatic 2D layer. An analysis of the porosity of both COFs showed a mean radius of the pores to be of ca. 4 nm, consistent with their chemical structure. The COFs form nanoparticles with a radius of around 100 nm. The thermal behavior of the COFs was further investigated by fast scanning calorimetry. These investigations showed that both COFs undergo a glass transition. The glass transition temperature of CPSF-EtO is found to be ca. 100 K higher than that for CPSF-MeO. This large difference in the glass transition is discussed to be due to a change in the interaction of the COF sheets induced by the longer ethoxy group. It might be assumed that for CPSF-EtO more individual COF sheets assemble to larger stacks than for CPSF-MeO. This agrees with the much larger surface area value found for CPSF-EtO compared to CPSF-MeO. To corroborate the results obtained be fast scanning calorimetry dielectric measurements were conducted which confirm the occurrence of a dynamic glass transition. The estimated temperature dependence of the relaxation rates of the dielectric relaxation and their absolute values agrees well with the data obtained by fast scanning calorimetry. Considering the fragility approach to the glass transition, it was further found that CPSF-MeO is a fragile glass former whereas CPSF-EtO behaves as a strong glass forming material. This difference in the fragility points also to distinct differences in the interaction between the 2D COF molecules in both materials.
KW - Covalent Organic frameworks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596770
DO - https://doi.org/10.1039/d3ma01123b
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Malpass-Evans, R.
A1 - McKeown, N.
A1 - Jalarvo, N.
A1 - Tyagi, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Microscopic molecular mobility of high-performance polymers of intrinsic microporosity revealed by neutron scattering – bend fluctuations and signature of methyl group rotation
N2 - Polymers of intrinsic microporosity exhibit a combination of high gas permeability and reasonable permselectivity, which makes them attractive candidates for gas separation membrane materials. The diffusional selective gas transport properties are connected to the molecular mobility of these polymers in the condensed state. Incoherent quasielastic neutron scattering was carried out on two polymers of intrinsic microporosity, PIM-EA-TB(CH3) and its demethylated counterpart PIM-EA-TB(H2), which have high Brunauer–Emmett–Teller surface area values of 1030 m2 g-1 and 836 m2 g-1, respectively. As these two polymers only differ in the presence of two methyl groups at the ethanoanthracene unit, the effect of methyl group rotation can be investigated solely. To cover a broad dynamic range, neutron time-of-flight was combined with neutron backscattering. The demethylated PIM-EA-TB(H2) exhibits a relaxation process with a weak intensity at short times. As the backbone is rigid and stiff this process was assigned to bendand-flex fluctuations. This process was also observed for the PIM-EA-TB(CH3). A further relaxation process is found for PIM-EA-TB(CH3), which is the methyl group rotation. It was analyzed by a jump-diffusion in a three-fold potential considering also the fact that only a fraction of the present hydrogens in PIM-EATB(CH3) participate in the methyl group rotation. This analysis can quantitatively describe the q dependence of the elastic incoherent structure factor. Furthermore, a relaxation time for the methyl group rotation can be extracted. A high activation energy of 35 kJ mol-1 was deduced. This high activation energy evidences a strong hindrance of the methyl group rotation in the bridged PIM-EA-TB(CH3) structure.
KW - Polymers of Intrinsic Microporosity
KW - Neutron Scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604114
DO - https://doi.org/10.1039/d4sm00520a
SP - 1
EP - 11
PB - RSC
AN - OPUS4-60411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed Aejaz
A1 - Szymoniak, Paulina
A1 - Zorn, R.
A1 - Böhning, Martin
A1 - Wolff, M.
A1 - Zamponi, M.
A1 - Schönhals, Andreas
T1 - Molecular mobility in high-performance polynorbornenes:A combined broadband dielectric, advanced calorimetry,and neutron scattering investigation
N2 - The molecular dynamics of two addition type polynorbornenes, exo-PNBSiand PTCNSi1, bearing microporosity has been investigated by broadbanddielectric spectroscopy, fast scanning calorimetry, and neutron scattering. Bothpolymers have the same side groups but different backbones. Due to theirfavorable transport properties, these polymers have potential applications inseparation membranes for gases. It is established in literature that molecularfluctuations are important for the diffusion of small molecules through poly-mers. For exo-PNBSi, two dielectric processes are observed, which are assignedto Maxwell/Wagner/Sillars (MWS) process due to blocking of charge carriersat internal voids or pore walls. For PTCNSi1, one MWS-polarization process isfound. This points to a bimodal pore-size distribution for exo-PNBSi. A glasstransition for exo-PNBSi and for PTCNSi1 could be evidenced for the first timeusing fast scanning calorimetry. For Tgand the corresponding apparent activa-tion energy, higher values were found for PTCNSi1 compared to exo-PNBSi.For both polymers, the neutron scattering data reveal one relaxation process.This process is mainly assigned to methyl group rotation probably overlayedby carbon–carbon torsional fluctuations.
KW - Advanced calorimetry
KW - Dielectric spectroscopy
KW - Neutron scattering
KW - Polynorbornenes
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547086
DO - https://doi.org/10.1002/pen.25995
SN - 0032-3888
VL - 62
IS - 7
SP - 2143
EP - 2155
PB - Wiley
AN - OPUS4-54708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghasem Zadeh Khorasani, Media
A1 - Silbernagl, Dorothee
A1 - Szymoniak, Paulina
A1 - Hodoroaba, Vasile-Dan
A1 - Sturm, Heinz
T1 - The effect of boehmite nanoparticles (gamma‐AlOOH) on nanomechanical and thermomechanical properties correlated to crosslinking density of epoxy
N2 - We show that complex physical and chemical interactions between boehmite nanoparticles and epoxy drastically affect matrix properties, which in the future will provide tuning of material properties for further optimization in applications from automotive to aerospace. We utilize intermodulation atomic force microscopy (ImAFM) for probing local stiffness of both particles and polymer matrix. Stiff particles are expected to increase total stiffness of nanocomposites and the stiffness of polymer should remain unchanged. However, ImAFM revealed that stiffness of matrix in epoxy/boehmite nanocomposite is significantly higher than unfilled epoxy. The stiffening effect of the boehmite on epoxy also depends on the particle concentration. To understand the mechanism behind property alteration induced by boehmite nanoparticles, network architecture is investigated using dynamic mechanical thermal analysis (DMTA). It was revealed that although with 15 wt% boehmite nanoparticles the modulus at glassy state increases, crosslinking density of epoxy for this composition is drastically low.
KW - Crosslinking density
KW - Epoxy
KW - Intermodulation
KW - Atomic force microscopy
KW - Nanomechanical properties
KW - Boehmite nanoparticles
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-476050
DO - https://doi.org/10.1016/j.polymer.2018.12.054
SN - 0032-3861
SN - 1873-2291
VL - 164
SP - 174
EP - 182
PB - Elsevier
AN - OPUS4-47605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Hiid, Gundula
A1 - Szymoniak, Paulina
A1 - Hertwig, Andreas
A1 - Schönhals, Andreas
T1 - Growth kinetics of the adsorbed layer of poly(bisphenol A carbonate) and its effect on the glass transition behavior in thin films
N2 - The glass transition behavior of thin films of poly(bisphenol A carbonate) (PBAC) was studied employing ellipsometry. The glass transition temperature increases with the reduction of the film thickness. This result is attributed to the formation of an adsorbed layer with a reduced mobility compared to bulk PBAC. Therefore, for the first time, the growth kinetics of the adsorbed layer of PBAC was investigated, prepared by leaching samples from a 200 nm thin film which were annealed for several times at three different temperatures. The thickness of each prepared adsorbed layer was measured by multiple scans using atomic force microscopy (AFM). Additionally, an unannealed sample was measured. Comparison of the measurements of the unannealed and the annealed samples provides proof of a pre-growth regime for all annealing temperatures which was not observed for other polymers. For the lowest annealing temperature after the pre-growth stage only a growth regime with a linear time dependence is observed. For higher annealing temperatures the growth kinetics changes from a linear to a logarithmic growth regime at a critical time. At the longest annealing times the films showed signs of dewetting where segments of the adsorbed film were removed from the substrate (dewetting by desorption). The dependence of the surface roughness of the PBAC surface on annealing time also confirmed that the films annealed at highest temperatures for the longest times desorbed from the substrate.
KW - Ultra thin polymer films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574531
DO - https://doi.org/10.1039/D3RA02020G
SN - 2046-2069
VL - 13
IS - 21
SP - 14473
EP - 14483
PB - RSC Publishing
CY - London
AN - OPUS4-57453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gawek, Marcel
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Growth kinetics of the adsorbed layer of poly(2-vinylpyridine) - An indirect observation of desorption of polymers from substrates
N2 - The growth kinetics of the adsorbed layer of poly(2-vinylpiridine) on silicon oxide is studied using a leaching technique which is based on the Guiselin brushes approach. The adsorbed layer is grown from a 200 nm thick P2VP film for several annealing time periods at different annealing temperatures. Then the film is solvent-leached, and the height of the remaining adsorbed layer is measured by atomic force microscopy. At the lowest annealing temperature only a linear growth regime is observed, followed by a plateau. Here, the molecular mobility of segments is too low to allow for a logarithmic growth. At higher annealing temperatures, both linear and logarithmic growth regimes are observed, followed by a plateau. At even higher annealing temperatures, the growth kinetics of the adsorbed layer changes.
A linear growth followed by logarithmic growth kinetics is observed for short annealing time periods. For longer annealing time periods, an upturn of the growth kinetics is observed. At the highest annealing temperature, only a logarithmic growth regime is found. The change in the growth kinetics is discussed by an alteration in the structure of the adsorbed layer. Moreover, the interaction between the polymer segments and the substrate becomes weaker due to both enthalpic and entropic effects. Therefore, at high annealing temperatures the polymer segments might more easily desorb from the substrate.
KW - Ultra thin polymer films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575423
DO - https://doi.org/10.1039/d3sm00129f
SN - 1744-683X
SN - 1744-6848
VL - 19
IS - 21
SP - 3975
EP - 3982
PB - Royal Society of Chemistry (RSC)
CY - London
AN - OPUS4-57542
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Senbill, Haytham
A1 - Gangan, Amr
A1 - Saeed, Ahmed M.
A1 - Gad, Mohammed E.
A1 - Zeb, Jehan
A1 - Fahmy, Alaa
T1 - Effects of copper/graphene oxide core-shell nanoparticles on Rhipicephalus ticks and their detoxification enzymes
N2 - Nanopesticides have been recently introduced as novel pesticides to overcome the drawbacks of using traditional synthetic pesticides. The present study evaluated the acaricidal activity of Copper/Graphene oxide core-shell nanoparticles against two tick species, Rhipicephalus rutilus and Rhipicephalus turanicus. The Copper/Graphene oxide core-shell nanoparticles were synthetized through the solution plasma (SP) method under different conditions. The nanoparticles synthesized at 180 W and 45 min were highly toxic to Rh. rutilus and Rh. turanicus, with 50% lethal concentration (LC50) values of 248.1 and 195.7 mg ml−1, respectively, followed by those which were synthesized at 120 W/30 mins (LC50 = 581.5 and 526.5 mg ml−1), 120 W/15 mins (LC50 = 606.9 and 686.7 mg ml−1), and 100/45 mins (LC50 = 792.9 and 710.7 mg ml−1), after 24 h of application. The enzyme assays revealed that 180 W/45 min treatment significantly inhibited the activity of acetylcholinesterase (115 ± 0.81 and 123 ± 0.33 U/ mg protein/min) and superoxide dismutase (290 ± 0.18 and 310 ± 0.92 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively, as compared with the negative control. The results also revealed a significantly increased catalase activity (895 ± 0.37 and 870 ± 0.31 U/ mg protein/min) in Rh. rutilus and Rh. turanicus, respectively. The above results indicated that Copper/Graphene oxide core-shell nanoparticles could be a promising alternatives for the management of ticks.
KW - Copper/graphene oxide
KW - Nanopesticides
KW - Rhipicephalus rutilus
KW - Rhipicephalus turanicus
KW - Acetylcholinesterase
KW - Antioxidants
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629359
DO - https://doi.org/10.1038/s41598-025-86560-4
SN - 2045-2322
VL - 15
SP - 1
EP - 12
PB - Springer Nature
CY - London
AN - OPUS4-62935
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Böhning, Martin
A1 - Frick, B.
A1 - Apple, M.
A1 - Mole, R. A.
A1 - De Souza, N. R.
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Confined Segmental Diffusion in Nanophase Separated Janus Polynorbornenes as Investigated by Quasielastic Neutron Scattering
N2 - A combination of neutron time-of-flight and neutron backscattering spectroscopy was used to investigate the molecular dynamics of Janus polynorbornenes (Janus poly(tricyclononenes)) on a microscopic level.
These Janus polynorbornenes, denoted as PTCNSiOR, have a semirigid backbone with −Si(OR)3 side groups attached to it. R represents the length of the alkyl side chain. Here side chain lengths of R = 3 (propyl) and R = 8 (octyl) were considered. It is worth mentioning that these polymers have some potential as active layers in gas separation membranes, especially for the separation of higher hydrocarbons. The combination of time-of-flight and backscattering will ensure a reasonably broad time window for analysis where the incoherent intermediate scattering function SInc(q,t) is considered. Previously, it was shown by X-ray investigations that the system undergoes a nanophase separation into alkyl side chain-rich domains surrounded by a backbone-rich matrix. For PTCNSiOPr (R = 3), the alkyl side-chain-rich domains are truly isolated in the backbone-rich matrix, whereas for PTCNSiOOc (R = 8) these domains percolate through the matrix. Further, it was also previously shown that the alkyl side-chain-rich domains undergo a glass transition. The advantage of neutron scattering experiments discussed here is that besides temporal also spatial information is obtained which will allow conclusions to be drawn about the type of molecular fluctuations. At the lowest measured temperature, the decay in Sinc(q,t) is due to the methyl group rotation. The methyl group dynamics is analyzed in terms of a modified jump-diffusion in a 3-fold potential and yields to a reasonable fraction of hydrogens which contribute to the methyl group rotation. At higher temperatures, the decay in SInc(q,t) is due to both the methyl group rotation and the segmental dynamics in the alkyl side-chain-rich domains. The segmental diffusion is modeled by a sublinear diffusion. For the analysis of the scattering function SInc(q,t) of PTCNSiOPr an elastic scattering due to the immobilized backbone-rich matrix must be taken into account. The analysis reveals that the segmental dynamics is confined by the finite size of alkyl chain-rich domains and that it is intrinsically heterogeneous in nature. Both effects are more pronounced for PTCNSiOPr in comparison to those of PTCNSiOOc.
KW - Polynorbornene
KW - Quasielastic Neutron Scattering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608712
DO - https://doi.org/10.1021/acs.macromol.4c01045
SP - 1
EP - 14
PB - ACS Publications
AN - OPUS4-60871
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zorn, R.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed Aejaz
A1 - Malpass-Evans, R.
A1 - McKeown, N.
A1 - Tyagi, M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Low frequency vibrations and diffusion in disordered polymers bearing an intrinsic microporosity as revealed by neutron scattering
N2 - The microscopic diffusion and the low frequency density of states (VDOS) of PIM-EATB(CH3) are investigated by inelastic and quasi-elastic neutron scattering where also the demethylated counterpart of PIM-EA-TB(H2) is considered. These intrinsic microporous polymers are characterized by large BET surface area values of several hundred m2/g and pore sizes between 0.5 and 2 nm. Detailed comparison is made to the archetype of polymers of intrinsic microporosity, PIM-1, and polynorbornenes also bearing a microporosity. Due to the wavelength of neutrons, the diffusion and vibrations can be addressed on microscopic length and time scales. From the inelastic neutron scattering experiments the low frequency density of states (VDOS) is estimated which shows excess contributions to the Debye-type VDOS known as Boson peak. It was found that the maximum frequency of the Boson peak decreases with increasing microporosity characterized by the BET surface area. However, besides the BET surface area, additional factors such as the backbone stiffness govern the maximum frequency of the Boson peak. Further the mean squared displacement related to microscopic motions was estimated from elastic fixed window scans. At temperatures above 175 K, the mean squared displacement PIM-EA-TB(CH3) is higher than that for the demethylated counterpart PIM-EA-TB(H2). The additional contribution found for PIM-EATB(CH3) is ascribed to the rotation of the methyl group in this polymer because the only difference between the two structures is that PIM-EA-TB(CH3) has methyl groups where PIM-EA-TB(H2) has none. A detailed comparison of the molecular dynamics is also made to that of PIM-1 and the microporous polynorbornene PTCNSi1. The manuscript focuses on the importance of vibrations and the localized molecular mobility characterized by the microscopic diffusion on the gas Transport in polymeric separation membranes. In the frame of the random gate model localized fluctuations can open or close bottlenecks between pores to enable the diffusion of gas molecules.
KW - Polymer of intrisic microporosity
KW - Neutron scattering
KW - Boson peak
KW - Methyl group rotation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538490
DO - https://doi.org/10.3390/cryst11121482
VL - 11
IS - 12
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Riechers, Birte
A1 - Maaß, Robert
A1 - Michalchuk, Adam
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Beyond conventional calorimetry: Unlocking thermal characterization with fast scanning techniques
N2 - Fast scanning calorimetry (FSC) has emerged as a transformative technique in thermal analysis, enabling the investigation of rapid and kinetically driven thermal transitions that are inaccessible to conventional differential scanning calorimetry. This review highlights the capabilities enabled by FSC for studying a wide range of materials under extreme thermal conditions, including polymers, pharmaceuticals, metallic glasses, nanocomposites, and hydrogels. By employing ultrafast heating and cooling rates, FSC allows for the suppression of crystallization, resolution of weak transitions, and analysis of thermally labile or size-limited samples. The technique is particularly valuable for probing glass transitions, relaxation phenomena, and phase behavior in systems with complex morphologies or confined geometries. Case studies demonstrate the use of FSC in characterizing vitrification, physical aging, and interfacial dynamics, as well as its application in emerging fields such as additive manufacturing, supramolecular systems, and neuromorphic materials. Together, these examples underscore the role that FSC plays in advancing the understanding of structure-property relationships across diverse material classes.
KW - Flash DSC
KW - Calorimetry
KW - Glass transition
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647405
DO - https://doi.org/10.1016/j.tca.2025.180177
VL - 754
SP - 1
EP - 14
PB - Elsevier B.V.
AN - OPUS4-64740
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Self-catalyzed polycondensation of glycolic acid: Influence of catalysts and synthesis of high-T m cyclic polyglycolides
N2 - The current work comprises three stages. First, the self-catalyzed polycondensation (SCP) of glycolic acid (GA) was studied in bulk or in suspension at 190°C or at 205°C. Cyclic poly(glycolic acid)s, cPGAs, with number average molecular weights (Mn´s) up 6 700 g mol-1 and dispersities below 2.0 were obtained. These cPGAs possess an unusual molecular weight distribution with a considerable predominance of cycles having degrees of polymerization of 28, 32 and 36. The cycles were formed in the solid state under thermodynamic control which favors the formation of extended-ring crystals. These cPGAs are an off-white, brittle porous mass that is easy to grind, yielding a flowable, crystalline powder suitable for 3D printing with laser sintering (SLS). In the second stage, the influence of non-toxic catalysts such as, Mg, Zn, Ti, Sn(II), Zr and Bi salts or complexes was studied. Compared to the results obtained with self-catalyzed polycondensation in bulk, the best metal catalysts increased the molecular weight by a factor of two to three. However, when compared to the results obtained with self-catalysis in 1,2-dichlorobenzene, the increase was limited to approximately 20%. The third stage examined the influence of 4-toluene sulfonic acid (TSA), which was found to favor the formation of the most perfect crystals with crystallinities up to 84% and the highest reported melting temperatures (up to 245 °C). This indicates the existence of a high Tm morphology, analogous to that of polylactide. Small-angle X-ray scattering (SAXS) measurements indicate that significant growth in crystal thickness is mainly responsible for these effects.
KW - MALDI-TOF MS
KW - Glycolic acid
KW - Cyclization
KW - Crystallization
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658566
DO - https://doi.org/10.1016/j.eurpolymj.2026.114711
SN - 1873-1945
VL - 251
SP - 1
EP - 9
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Anderhalten, Lina
A1 - Höfer, N.
A1 - Dymnikova, D.
A1 - Hahndorf, J.
A1 - Taupitz, M.
A1 - Traub, Heike
A1 - Teutloff, C.
A1 - Infante-Duarte, C.
A1 - Bittl, R.
T1 - EPR-based Assessment of Gadolinium-based Contrast Agent Retention and Gadolinium Transchelation in Inflamed Murine Brain
N2 - Objectives:
In view of the mounting evidence for markedly increased cerebellar Gd retention under neuroinflammatory conditions after repeated linear GBCA administration in vivo, we aimed to discriminate between Gd retained within the GBCA complex and forms dissociated from the complex within the CNS and to characterize the chemical environment of the released Gd³⁺. For this purpose, we used electron paramagnetic resonance (EPR) spectroscopy, which enables direct detection of Gd³⁺ release and evaluation of its molecular surroundings in intact cerebellar tissue from inflamed and noninflamed brain sections exposed to either linear or macrocyclic GBCAs.
Materials and Methods:
We performed EPR and electron-nuclear double resonance (ENDOR) experiments on sub-mm brain samples taken after administration of linear gadopentetate-dimeglumine and macrocyclic gadobutrol in vivo in a murine multiple sclerosis model and ex vivo in organotypic hippocampal slice cultures under inflammatory conditions. Complementary mass spectrometry (MS) and MRI calibration experiments on Gd-spiked homogenized mouse brain tissue were used to identify potential Gd bindings and assess the relaxation-active fraction of retained Gd.
Results:
EPR detected µM range Gd levels in intact cerebellar biopsies and slices and distinguished between complex-bound and released Gd following linear GBCA administration in vivo. In biopsies, we detected by ENDOR phosphorus-containing molecules in the microenvironment of released Gd. Binding to inorganic ligands was evidenced using MS and MRI calibration experiments in homogenized mouse brain tissue.
Conclusions:
EPR and ENDOR proved to be sensitive methods for detecting Gd³⁺ release and characterizing retained Gd species within intact brain tissue. Our findings demonstrate inflammation-promoted Gd retention, underscore the importance of integrating in vivo and ex vivo analyses to unravel mechanisms of long-term Gd retention, and suggest that conventional MRI may underestimate the true extent of Gd accumulation, especially under neuroinflammatory conditions.
KW - Electron paramagnetic resonance
KW - Gadolinium
KW - Contrast agent
KW - ICP-MS
KW - Inflammation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658688
DO - https://doi.org/10.1097/RLI.0000000000001280
SN - 1536-0210
SP - 1
EP - 13
PB - Lippincott Williams & Wilkins
CY - Philadelphia, Pa.
AN - OPUS4-65868
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
A1 - Said, Samir
A1 - Rücker, Werner
T1 - Excitation and Transmission of Train-Induced Ground and Building Vibrations—Measurements, Analysis, and Prediction
N2 - Measurement results of train-induced vibrations are evaluated for characteristic frequencies, amplitudes and spectra, leading to a prediction which is based on transfer functions of the vehicle–track–soil system, the soil, and the building–soil system. The characteristic frequencies of train-induced vibrations are discussed following the propagation of vibrations from the source to the receiver: out-of-roundness frequencies of the wheels, the sleeper passage frequency, the vehicle–track eigenfrequency, the car-length frequency and multiples, axle-distance frequencies, bridge eigenfrequencies, the building–soil eigenfrequency, and floor eigenfrequencies. Amplitudes and spectra are compared for different train and track types, for different train speeds, and for different soft and stiff soils, where high frequencies are typically found for stiff soil and low frequencies for soft soil. The ground vibration is between the cut-on frequency due to the layering and the cut-off frequency due to the material damping of the soil, but the dominant frequency range also changes with distance from the track. The frequency band of the axle impulses due to the passing static loads obtains a signature from the axle sequence. The high amplitudes between the zeros of the axle-sequence spectrum are measured at the track, the bridge, and also in the ground vibrations, which are even dominant in the far field. A prediction software is presented, which includes all three parts: the excitation by the vehicle–track interaction, the wave transmission through the soil, and the transfer into a building.
KW - Train-induced vibration
KW - Vehicle excitation
KW - Track response
KW - Bridge resonance
KW - Ground vibration
KW - Soil–building transfer
KW - Floor resonance
KW - Axle-sequence spectrum
KW - Vehicle track eigenfrequency
KW - Axle impulses
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658722
DO - https://doi.org/10.3390/vibration9010021
SN - 2571-631X
VL - 9
IS - 1
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-65872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Braun, M.
A1 - Reuter, T.
A1 - Bellon, Carsten
A1 - Orth, Anthony
A1 - Bartscher, M.
A1 - Li, K.
A1 - Kasperl, S.
A1 - Kirschbaum, K.
A1 - Hausotte, T.
T1 - Simulation of a real dimensional CT-measurement study using a calibrated aluminum specimen
N2 - For the long-term goal of determining the measurement uncertainty of dimensional computed tomography (CT) measurements with simulation, it is necessary to prove the compatibility of the digital model with its real counterpart. A study of repeated CT measurements of a calibrated aluminum specimen was performed and afterwards simulated. A first indicator for a sufficiently good digital representation is the agreement of dimensional measurands, such as diameters and center-to-center distances. Results show in general good agreement between simulation and real measurement. A detailed discussion of the results as well as a proposed criterion for testing the simulation will be shown in the full paper.
T2 - 10th International Symposium on Digital Industrial Radiography and Computed Tomography (DIR 2025)
CY - Paris, France
DA - 01.07.2025
KW - Simulation
KW - Digital metrological twin
KW - Computed tomography
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658752
DO - https://doi.org/10.58286/31414
SN - 1435-4934
VL - 30
IS - 8
SP - 1
EP - 9
PB - NDT.net
CY - Kirchwald
AN - OPUS4-65875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Guiping
A1 - Liu, Ye
A1 - Schultz, Thorsten
A1 - Exner, Moritz
A1 - Muydinov, Ruslan
A1 - Wang, Hui
A1 - Scheurell, Kerstin
A1 - Huang, Jieyang
A1 - Szymoniak, Paulina
A1 - Pinna, Nicola
A1 - Koch, Norbert
A1 - Adelhelm, Philipp
A1 - Bojdys, Michael J.
T1 - One‐Pot Synthesis of High‐Capacity Sulfur Cathodes via In‐Situ Polymerization of a Porous Imine‐Based Polymer
N2 - AbstractLithium‐ion batteries, essential for electronics and electric vehicles, predominantly use cathodes made from critical materials like cobalt. Sulfur‐based cathodes, offering a high theoretical capacity of 1675 mAh g−1 and environmental advantages due to sulfur's abundance and lower toxicity, present a more sustainable alternative. However, state‐of‐the‐art sulfur‐based electrodes do not reach the theoretical capacities, mainly because conventional electrode production relies on mixing of components into weakly coordinated slurries. Consequently, sulfur‘s mobility leads to battery degradation—an effect known as the “sulfur‐shuttle”. This study introduces a solution by developing a microporous, covalently‐bonded, imine‐based polymer network grown in situ around sulfur particles on the current collector. The polymer network (i) enables selective transport of electrolyte and Li‐ions through pores of defined size, and (ii) acts as a robust host to retain the active component of the electrode (sulfur species). The resulting cathode has superior rate performance from 0.1 C (1360 mAh g−1) to 3 C (807 mAh g−1). Demonstrating a high‐performance, sustainable sulfur cathode produced via a simple one‐pot process, our research underlines the potential of microporous polymers in addressing sulfur diffusion issues, paving the way for sulfur electrodes as viable alternatives to traditional metal‐based cathodes.
KW - In-situ polymerization
KW - Sulfur cathodes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604215
DO - https://doi.org/10.1002/anie.202400382
SN - 1433-7851
SP - 1
EP - 11
PB - Wiley VHC-Verlag
AN - OPUS4-60421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elert, Anna Maria
A1 - Chen, Yong-Cin
A1 - Smales, Glen Jacob
A1 - Topolniak, Ievgeniia
A1 - Sturm, Heinz
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Effects of the charge density of nanopapers based on carboxymethylated cellulose nanofibrils investigated by complementary techniques
N2 - Cellulose nanofibrils (CNFs) with different charge densities were prepared and investigated by a combination of different complementary techniques sensitive to the structure and molecular dynamics of the system. The morphology of the materials was investigated by scanning electron microscopy (SEM) and X-ray scattering (SAXS/WAXS). The latter measurements were quantitatively analyzed yielding to molecular parameters in dependence of the charge density like the diameter of the fibrils, the distance between the fibrils, and the dimension of bundles of nanofibrils, including pores. The influence of water on the properties and the charge density is studied by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC) and broadband dielectric spectroscopy. The TGA measurements reveal two mass loss processes. The one at lower temperatures was related to the loss of water, and the second process at higher temperatures was related to the chemical decomposition. The resulting char yield could be correlated to the distance between the microfibrils. The DSC investigation for hydrated CNFs revealed three glass transitions due to the cellulose segments surrounded by water molecules in different states. In the second heating scan, only one broad glass transition is observed. The dielectric spectra reveal two relaxation processes. At low temperatures or higher frequencies, the β-relaxation is observed, which is assigned to localized fluctuation of the glycosidic linkage. At higher temperatures and lower frequencies, the α-relaxation takes places. This relaxation is due to cooperative fluctuations in the cellulose segments. Both processes were quantitatively analyzed. The obtained parameters such as the relaxation rates were related to both the morphological data, the charge density, and the content of water for the first time.
KW - Cellulose nanofibrils
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600528
DO - https://doi.org/https://doi.org/10.1021/acsomega.4c00255
SN - 2470-1343
VL - 9
SP - 20152
EP - 20166
PB - ACS
AN - OPUS4-60052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Smales, Glen Jacob
A1 - Henning, S.
A1 - Li, Z.
A1 - Wang, D.-Y.
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
T1 - Calorimetric and Dielectric Investigations of Epoxy-Based Nanocomposites with Halloysite Nanotubes as Nanofillers
N2 - Epoxy nanocomposites are promising materials for industrial applications (i.e., aerospace, marine and automotive industry) due to their extraordinary mechanical and thermal properties. Here, the effect of hollow halloysite nanotubes (HNT) on an epoxy matrix (Ep) was the focus of the study. The structure and molecular mobility of the nanocomposites were investigated using a combination of X-ray scattering, calorimetry (differential (DSC) and fast scanning calorimetry (FSC)) and dielectric spectroscopy. Additionally, the effect of surface modification of HNT (polydopamine (PDA) and Fe(OH)3 nanodots) was considered. For Ep/HNT, the glass transition temperature (Tg) is was de-creased due to a nanoparticle-related decrease of the crosslinking density. For the modified system, Ep/m-HNT, the surface modification resulted in enhanced filler–matrix interactions leading to higher Tg values than the pure epoxy in some cases. For Ep/m-HNT, the amount of interface formed between the nanoparticles and the matrix ranged from 5% to 15%. Through BDS measurements, localized fluctuations were detected as a β- and γ-relaxation, related to rotational fluctuations of phenyl rings and local reorientations of unreacted components. A combination of calorimetry and BDS dielectric spectroscopy revealed a dynamic and structural heterogeneity of the matrix, as confirmed by two glassy dynamics in both systems, related to regions with different crosslinking densities.
KW - Rigid amorphous fraction
KW - Epoxy nanocomposites
KW - Halloysite nanotubes
KW - X-ray scattering
KW - Differential scanning calorimetry
KW - Broadband dielectric spectroscopy
KW - Flash DSC
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526668
DO - https://doi.org/10.3390/polym13101634
VL - 13
IS - 10
SP - 1634
PB - MDPI
AN - OPUS4-52666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zosef, M.
A1 - Fahmy, Alaa
A1 - El Hotaby, W.
A1 - Hassan, A.
A1 - Khalil, A.
A1 - Anis, B.
T1 - High performance graphene-based PVF foam for lead removal from water
N2 - The synthesis and optimization of superior and eco-friendly sorbents for Pb(II) pose a great challenge in the field of water treatment. The sorbent was developed by introducing graphene oxide (GO) into the matrix of polyvinyl formaldehyde (PVF) foam. The immobilization of GO in PVF results in significant increase in the maximum adsorption capacity (Qt) of GO powder for Pb(II), from ≈800 to ≈1730 mg g−1 in the case of GO/PVF foam. As compared with GO powder in Pb(II) aqueous solutions, PVF matrix keeps GO sheets stable without any agglomeration. The large surface area of GO sheet allows the abundant oxygenated functional groups on its surface to participate effectively in the Pb(II) adsorption process, leading to the huge increase of the Qt. Adsorption isotherms and kinetic studies indicated that the sorption process of Pb(II) on GO/PVF was done on heterogenous surface by ion-exchange reaction. The GO/PVF foam showed an excellent reusability for more than 10 cycles with almost the same efficiency and without any significant change in its physical properties.
KW - Water treatment
KW - Graphene oxide
KW - Lead ions
KW - Polyvinyl formaldehyde foam
KW - Superior sorbent
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523013
DO - https://doi.org/10.1016/j.jmrt.2020.08.011
VL - 9
IS - 5
SP - 11861
EP - 11875
PB - Elsevier B.V.
AN - OPUS4-52301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Saied, M. A. A.
A1 - Morgan, N.
A1 - Abdelbary, H.
A1 - Bahy, S. M.
A1 - Schönhals, Andreas
A1 - Friedrich, J. F.
T1 - Modified polyvinyl chloride membrane grafted with an ultra-thin polystyrene film: structure and electrochemical properties
N2 - The work explores the synthesis and the properties of a novel composite membrane System based on modified polystyrene (PS) grafted onto a polyvinyl chloride (PVC) membrane.
PVC membranes were prepared by solution-casting followed by exposure to an atmospheric pressure dielectric barrier discharge (DBD) with O2 to obtain an activated Surface for grafting PS to it. Moreover, the thus prepared membranes were chemically modified furthermore by amination with polyethyleneimine or sulfonation with 4 M sulfuric acid.
The membrane surface characteristics such as wettability, structure and morphology were investigated using water contact angle measurements, attenuated total reflection Fourier transform infrared spectroscopy and scanning electron microscopy experiments. The thermogravimetric stability and electrolytic responses of the membranes were studied utilizing TGA, ion exchange capacity (IEC), and solvent uptake. A significant result of plasma and chemical modification was to produce a membrane material with low permeability. Thus, the methanol permeability of the sulfonated membranes measured for 12 h was measured to 2.34$10� 8 cm2 s� 1 compared to 177.00$10� 8 cm2 s� 1 of Nafion 117®which is considered as a benchmark. This result indicates that the prepared sulfonated samples are an innovative and effective material for decreasing the methanol crossover in fuel cells to a great extent. This makes the PVC-g-St membranes are promising and attractive as new materials for polyelectrolyte membrane for fuel cells.
KW - Electrolyte membrane
KW - Fuell cells
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-526794
DO - https://doi.org/10.1016/j.jmrt.2021.04.018
VL - 12
SP - 2273
EP - 2284
PB - Elsevier B.V.
AN - OPUS4-52679
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Matthias
A1 - Baldan, A.
A1 - Beelen, R.
A1 - de Boed, E. J.J.
A1 - Tuma, Dirk
A1 - Kipphardt, Heinrich
A1 - Wilke, Olaf
A1 - van der Veen, A. M.H.
T1 - Primary gas standards for the determination of sulfur-based impurities at trace level in hydrogen
N2 - Hydrogen fuel quality needs to comply with ISO 14687:2025 to avoid harmful impact on applications using proton-exchange membrane (PEM) fuel cells. For total sulfur as one of the most impactful contaminants, an amount fraction of 4 nmol/mol has been set as threshold (so-called Grade D quality). In this study, novel gaseous primary gas standards (PGS) of seven sulfur compounds were prepared either gravimetrically at 1000 nmol/mol, 100 nmol/mol, and 10 nmol/mol, or dynamically diluted down to 4 nmol/mol in hydrogen and argon matrices with relative expanded uncertainties well below 10 % (k = 2) and proven stability of at least 9–12 months. Two different cylinder passivation treatments were compared, with one treatment identified as unsuitable since reactions took place within the mixture. By performing a cross-check study, equivalence between both sets of PGS could be demonstrated (≤ 5 % relative deviation for most of the sulfur species).
KW - Hydrogen quality
KW - ISO 14687
KW - Sulfur impurities
KW - Primary gas standards
KW - TD-GC/SCD
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656759
DO - https://doi.org/10.1016/j.ijhydene.2026.154461
SN - 0360-3199
VL - 224
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-65675
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riechers, Birte
A1 - Pekin, Thomas C.
A1 - Luo, Xin-Yu
A1 - Sun, Yonghao
A1 - Koch, Christoph T.
A1 - Derlet, Peter M.
A1 - Maaß, Robert
T1 - Spatial distribution and connectivity of medium-range order signatures in a metallic glass probed with simulated and experimental 4DSTEM
N2 - challenge. Here, we assess the statistical signature of local diffraction symmetries and their spatial distribution obtained with transmission electron microscopy in both experimentally cast Pd-based MGs and simulated binary model glasses. A detailed analysis of diffraction symmetries from the model glass shows that microstructural coarsening is dominated by icosahedra and Frank–Kasper polyhedra. While symmetries for these motifs are less significant for the laboratory-cast Pd-based glass, clear signatures of symmetry-cluster coarsening as a function of relaxation state are observed in both experiments and simulations, without any indications for crystallization. These findings give support for a qualitatively similar evolution of a glassy microstructure at the medium-range order length scale during glass relaxation.
KW - Metallic glass
KW - TEM
KW - Molecular dynamics simulations
KW - Glass structure
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657772
DO - https://doi.org/10.1016/j.jallcom.2026.186631
SN - 0925-8388
VL - 1058
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65777
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chan, George C.-Y.
A1 - Hieftje, Gary M.
A1 - Omenetto, Nicoló
A1 - Axner, Ove
A1 - Bengtson, Arne
A1 - Bings, Nicolas H.
A1 - Blades, Michael W.
A1 - Bogaerts, Annemie
A1 - Bolshov, Mikhail A.
A1 - Broekaert, José A.C.
A1 - Chan, WingTat
A1 - Costa-Fernández, José M.
A1 - Crouch, Stanley R.
A1 - De Giacomo, Alessandro
A1 - D’Ulivo, Alessandro
A1 - Engelhard, Carsten
A1 - Falk, Heinz
A1 - Farnsworth, Paul B.
A1 - Florek, Stefan
A1 - Gamez, Gerardo
A1 - Gornushkin, Igor B.
A1 - Günther, Detlef
A1 - Hahn, David W.
A1 - Hang, Wei
A1 - Hoffmann, Volker
A1 - Jakubowski, Norbert
A1 - Karanassios, Vassili
A1 - Koppenaal, David W.
A1 - Kenneth Marcus, R.
A1 - Noll, Reinhard
A1 - Olesik, John W.
A1 - Palleschi, Vincenzo
A1 - Panne, Ulrich
A1 - Pisonero, Jorge
A1 - Ray, Steven J.
A1 - Resano, Martín
A1 - Russo, Richard E.
A1 - Scheeline, Alexander
A1 - Smith, Benjamin W.
A1 - Sturgeon, Ralph E.
A1 - Todolí, José-Luis
A1 - Tognoni, Elisabetta
A1 - Vanhaecke, Frank
A1 - Webb, Michael R.
A1 - Winefordner, James D.
A1 - Yang, Lu
A1 - Yu, Jin
A1 - Zhang, Zhanxia
T1 - Landmark Publications in Analytical Atomic Spectrometry: Fundamentals and
Instrumentation Development
N2 - The almost-two-centuries history of spectrochemical analysis has generated a body of literature so vast that it has become nearly intractable for experts, much less for those wishing to enter the field. Authoritative, focused reviews help to address this problem but become so granular that the overall directions of the field are lost. This broader perspective can be provided partially by general overviews but then the thinking, experimental details, theoretical underpinnings and instrumental innovations of the original work must be sacrificed. In the present compilation, this dilemma is overcome by assembling the most impactful publications in the area of analytical atomic spectrometry. Each entry was proposed by at least one current expert in the field and supported by a narrative that justifies its inclusion. The entries were then assembled into a coherent sequence and returned to contributors for a round-robin review.
KW - Analytical atomic spectrometry
KW - Spectroscopy
KW - Instrumental analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621588
DO - https://doi.org/10.1177/00037028241263567
SN - 1943-3530
VL - 78
SP - 1
EP - 456
PB - Sage
CY - London
AN - OPUS4-62158
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kimiaei, E.
A1 - Farooq, M.
A1 - Szymoniak, Paulina
A1 - Ahmadi, Shayan
A1 - Babaeipour, S.
A1 - Schönhals, Andreas
A1 - Österberg, M.
T1 - The role of lignin as interfacial compatibilizer in designing lignocellulosic-polyester composite films
N2 - Advancing nanocomposites requires a deep understanding and careful design of nanoscale interfaces, as interfacial interactions and adhesion significantly influence the physical and mechanical properties of these materials. This study demonstrates the effectiveness of lignin nanoparticles (LNPs) as interfacial compatibilizer between hydrophilic cellulose nanofibrils (CNF) and a hydrophobic polyester, polycaprolactone (PCL). In this context, we conducted a detailed analysis of surface-to-bulk interactions in both wet and dry conditions using advanced techniques such as quartz crystal microbalance with dissipation (QCM-D), atomic force microscopy (AFM), water contact angle (WCA) measurements, broadband dielectric spectroscopy (BDS), and inverse gas chromatography (IGC).
QCM-D was employed to quantify the adsorption behavior of LNPs on CNF and PCL surfaces, demonstrating LNPs’ capability to interact with both hydrophilic and hydrophobic phases, thereby enhancing composite material properties. LNPs showed extensive adsorption on a CNF model film (1186 ± 178 ng.cm−2) and a lower but still significant adsorption on a PCL model film (270 ± 64 ng.cm−2). In contrast, CNF adsorption on a PCL model film was the lowest, with a sensed mass of only 136 ± 35 ng.cm−2. These findings were further supported by comparing the morphology and wettability of the films before and after adsorption, using AFM and WCA analyses. Then, to gain insights into the molecular-level interactions and molecular mobility within the composite in dry state, BDS was employed. The BDS results showed that LNPs improved the dispersion of PCL within the CNF network. To further investigate the impact of LNPs on the composites’ interfacial properties, IGC was employed. This analysis showed that the composite films containing LNPs exhibited lower surface energy compared to those composed of only CNF and PCL. The presence of LNPs likely reduced the availability of surface hydroxyl groups, thus modifying the physicochemical properties of the interface. These changes were particularly evident in the heterogeneity of the surface energy profile, indicating that LNPs significantly altered the interfacial characteristics of the composite materials.
Overall, these findings emphasize the necessity to control the interfaces between components for next-generation nanocomposite materials across diverse applications.
KW - Lignin
KW - Nanocomposites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615098
DO - https://doi.org/10.1016/j.jcis.2024.10.083
SN - 0021-9797
VL - 679
SP - 263
EP - 275
PB - Elsevier Inc.
AN - OPUS4-61509
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Qu, Xintong
A1 - Abbasi, M.
A1 - Pauw, Brian Richard
A1 - Henning, S.
A1 - Li, Z.
A1 - Wang, D.-Y.
A1 - Schick, C.
A1 - Saalwächter, K.
A1 - Schönhals, Andreas
T1 - Spatial inhomogeneity, Interfaces and Complex Vitrification Kinetics in a Network Forming Nanocomposite
N2 - A detailed calorimetric study on an epoxy-based nanocomposite system was performed employing bisphenol A diglycidyl ether (DGEBA) cured with diethylenetriamine (DETA) as the polymer matrix and taurine-modified MgAL layered double hydroxide (T-LDH) as nanofiller. The -NH2 group of taurine can react with DGEBA improving the interaction of the polymer with the filler. The combined X-ray scattering, and electron microscopy data showed that the nanocomposite has a partially exfoliated morphology. Calorimetric studies were performed with conventional DSC, temperature modulated DSC (TMDSC) and fast scanning calorimetry (FSC) in the temperature modulated approach (TMFSC) to investigate the vitrification and molecular mobility in dependence of the filler concentration. First, TMDSC and NMR were used to estimate the amount of the rigid amorphous fraction which consists of immobilized polymer segments at the nanoparticle surface. It was found to be 40 wt% for the highest filler concentration, indicating that the interface dominates the overall macroscopic properties and behavior of the material to a great extent. Second, the relaxation rates of the α-relaxation obtained by TMDSC and TMFSC were compared with the thermal and dielectric relaxation rates measured by static FSC. The investigation revealed that the system shows two distinct α-relaxation processes. Furthermore, also two separate vitrification mechanisms were found for a bulk network-former without geometrical confinement as also confirmed by NMR. This was discussed in terms of the intrinsic spatial heterogeneity on a molecular scale, which becomes more pronounced with increasing nanofiller content.
KW - Polymer based Nanocomposites
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523199
DO - https://doi.org/10.1039/d0sm01992e
SN - 1744-6848
VL - 17
IS - 10
SP - 2775
EP - 2790
PB - Royal Society of Chemistry
AN - OPUS4-52319
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Z.
A1 - Raab, A.
A1 - Kolmangadi, Mohamed Aejaz
A1 - Busch, M.
A1 - Grunwald, M.
A1 - Demel, F.
A1 - Bertram, F.
A1 - Kityk, A. V.
A1 - Schönhals, Andreas
A1 - Laschat, S.
A1 - Huber, P.
T1 - Self-Assembly of Ionic Superdiscs in Nanopores
N2 - Discotic ionic liquid crystals (DILCs) consist of self-assembled superdiscs of cations and anions that spontaneously stack in linear columns with high one-dimensional ionic and electronic charge mobility, making them prominent model systems for functional soft matter. Compared to classical nonionic discotic liquid crystals, many liquid crystalline structures with a combination of electronic and ionic conductivity have been reported, which are of interest for separation membranes, artificial ion/proton conducting membranes, and optoelectronics. Unfortunately, a homogeneous alignment of the DILCs on the macroscale is often not achievable, which significantly limits the applicability of DILCs. Infiltration into nanoporous solid scaffolds can, in principle, overcome this drawback. However, due to the experimental challenges to scrutinize liquid crystalline order in extreme spatial confinement, little is known about the structures of DILCs in nanopores. Here, we present temperaturedependent high-resolution optical birefringence measurement and 3D reciprocal space mapping based on synchrotron X-ray scattering to investigate the thermotropic phase behavior of dopamine-based ionic liquid crystals confined in cylindrical channels of 180 nm diameter in macroscopic anodic aluminum oxide membranes. As a function of the membranes’ hydrophilicity and thus the molecular anchoring to the pore walls (edge-on or face-on) and the variation of the hydrophilic−hydrophobic balance between the aromatic cores and the alkyl side chain motifs of the superdiscs by tailored chemical synthesis, we find a particularly rich phase behavior, which is not present in the bulk state. It is governed by a complex interplay of liquid crystalline elastic energies (bending and splay deformations), polar interactions, and pure geometric confinement and includes textural transitions between radial and axial alignment of the columns with respect to the long nanochannel axis. Furthermore, confinement-induced continuous order formation is observed in contrast to discontinuous first-order phase transitions, which can be quantitatively described by Landau-de Gennes free energy models for liquid crystalline order transitions in confinement. Our observations suggest that the infiltration of DILCs into nanoporous solids allows tailoring their nanoscale texture and ion channel formation and thus their electrical and optical functionalities over an even wider range than in the bulk state in a homogeneous manner on the centimeter scale as controlled by the monolithic nanoporous scaffolds.
KW - Ionic Liquid Crystals
KW - Nanopropous materials
KW - Landau de-Gennes analysis
KW - X-ray scattering
KW - Optical birefringence
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600797
DO - https://doi.org/10.1021/acsnano.4c01062
SN - 1936-0851
VL - 18
IS - 22
SP - 14414
EP - 14426
PB - ACS
AN - OPUS4-60079
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nikitin, D.
A1 - Biliak, K.
A1 - Protsak, M.
A1 - Adejube, B.
A1 - Ali-Ogly, S.
A1 - Škorvanková, K.
A1 - Červenková, V.
A1 - Katuta, R.
A1 - Tosco, M.
A1 - Hanuš, J.
A1 - Černochová, Z.
A1 - Černoch, P.
A1 - Štěpánek, P.
A1 - Boiko, O.
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Faupel, F.
A1 - Biedermann, H.
A1 - Vahl, A.
A1 - Choukourov, A.
T1 - Unveiling the Fundamental Principles of Reconfigurable Resistance States in Silver/Poly(ethylene glycol) Nanofluids
N2 - Developing novel memristive systems aims to implement key principles of biological neuron assemblies – plasticity, adaptivity, and self-organization – into artificial devices for parallel, energy-efficient computing. Solid-state memristive devices, such as crossbar arrays and percolated nanoparticle (NP) networks, already demonstrate these properties. However, closer similarity to neural networks is expected from liquid-state systems, including polymer melts, which remain largely unexplored. Here, the resistive switching in silver/poly(ethylene glycol) (Ag/PEG) nanofluids, prepared by depositing gas-aggregated Ag NPs into PEGs of varying molecular mass, is investigated.
These systems form long-range conductive NP bridges with reconfigurable resistance states in response to an electric field. The zeta-potential of Ag NPs and molecular mobility of PEG determine the prevalence of low resistance (ohmic) state, high resistance states (poor conductance) or intermediate transition states governed by space-charge-limited conduction or electron tunneling. The occurrence of these states is given by the interparticle gaps, which are determined by the conformation of PEG molecules adsorbed on the NPs. It is presented, for the first time, an equivalent circuit model for the Ag/PEG system. These findings pave the way to adopt polymer melts as matrices for neuromorphic engineering and bio-inspired electronics.
KW - Nanofluids
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635351
DO - https://doi.org/10.1002/advs.202505103
VL - 12
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-63535
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Ahamadi, Shayan
A1 - Hülagü, Deniz
A1 - Hidde, Gundula
A1 - Hertwig, Andreas
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Investigations of the adsorbed layer of polysulfone: Influence of the thickness of the adsorbed layer on the glass transition of thin films
N2 - This work studies the influence of the adsorbed layer on the glass transition of thin films of polysulfone. Therefore, the growth kinetics of the irreversibly adsorbed layer of polysulfone on silicon substrates was first investigated using the solvent leaching approach, and the thickness of the remaining layer was measured with atomic force microscopy. Annealing conditions before leaching were varied in temperature and time (0–336 h). The growth kinetics showed three distinct regions: a pre-growth step where it was assumed that phenyl rings align parallel to the substrate at the shortest annealing times, a linear growth region, and a crossover from linear to logarithmic growth observed at higher temperatures for the longest annealing times. No signs of desorption were observed, pointing to the formation of a strongly adsorbed layer.
Second, the glass transition of thin polysulfone films was studied in dependence on the film thickness using spectroscopic ellipsometry. Three annealing conditions were compared: two with only a tightly bound layer formed in the linear growth regime and one with both tightly bound and loosely adsorbed layers formed in the logarithmic growth regime. The onset thickness and increase in the glass transition temperature increases with annealing time and temperature. These differences were attributed to the distinct conformations of the formed adsorbed layers.
KW - Glass transition
KW - Adsorbed Layer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607701
DO - https://doi.org/10.1063/5.0223415
SN - 0021-9606
VL - 161
IS - 5
SP - 1
EP - 12
PB - AIP Publishing
AN - OPUS4-60770
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Juranyi, F.
A1 - Kruteva, M.
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Low-Frequency Vibrational Density of States of Nanophase- Separated Poly(n‑alkyl methacrylate)s: Confined Phonons and Relationship to Specific Heat
N2 - This study investigates the low-frequency vibrational Density of states of nanophase-separated poly(n-alkyl methacrylate)s (PnMAs) and its relationship to specific heat. This system undergoes a nanophase separation for n > 1 in alkyl side chain-rich domains and a backbone-rich matrix. Using inelastic neutron scattering, the low-frequency vibrational density of states (Boson peak, BP) of PnMAs with varying alkyl side chain lengths (methyl, butyl, hexyl, and octyl) is measured. The results reveal that the BP shifts to higher frequencies with increasing side chain length reaching a maximum. This result indicates a counterbalance of confinement effects and the scattering of the matrix. The behavior of the Boson peak of the PnMAs is compared to other nanophase-separated systems, such as Janus-polynorbornenes and hexakis(n-alkyloxy)triphenylene discotic liquid crystals. The study also explores the connection between the BP and specific heat capacity, showing a linear relationship between the maximum frequency of the BP and the maximum temperature of the specific heat capacity anomaly. Moreover, from the measured vibrational density of states, the specific heat capacity is calculated and compared to experimental results. The comparison reveals qualitative agreement between the calculated and experimental data. These findings provide evidence for the sound wave interpretation of the Boson peak.
KW - Inelastic Neutron Scattering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636928
DO - https://doi.org/10.1021/acs.macromol.5c00898
SN - 1520-5835
SP - 1
EP - 12
PB - ACS Publications
AN - OPUS4-63692
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Böhning, Martin
A1 - De Souza, N. R.
A1 - Juranyi, F.
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Inelastic and Quasielastic Neutron Scattering on Polynorbornenes with Bulky Carbocyclic Side groups
N2 - This study investigates the molecular mobility and vibrational properties of polynorbornenes with bulky carbocyclic side groups using inelastic and quasielastic neutron scattering techniques. The polymers, synthesized via metathesis and addition polymerization, exhibit varying degrees of microporosity, which ignificantly influences their gas separation performance. By inelastic neutron scattering experiments, it could be shown that all considered polymers have excess contributions to the low frequency vibrational density of states known as the Boson peak. The maximum frequency of the Boson peak correlates to the microporosity of the polymers.
This correlation supports the sound wave interpretation of the Boson peak, suggesting that the microporous structure enhances the compressibility of the material at a microscopic length scale. The molecular mobility, particularly the methyl group rotation, was characterized using elastic scans and quasielastic neutron scattering. The study revealed a temperature dependent relaxation process, with the onset of molecular fluctuations observed around 200 K for the polymer containing methyl groups. For the polymer having no methyl groups only elastic scattering is observed. The methyl group rotation was analyzed in terms of a jump diffusion in a threefold potential with three equivalent energy minima. This leads to an almost correct description of the q dependence of the elastic incoherent scattering function when the number of hydrogen nuclei undergoing the methyl group rotation is considered. It was further evidenced that the fraction of methyl undergoing the methyl group rotation increases with increasing temperature.
KW - Polymers of Intrinsic Microporosity
KW - Neutron scattering
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630297
DO - https://doi.org/10.1016/j.polymer.2025.128358
SN - 1873-2291
VL - 328
SP - 241
PB - Elsevier Ltd.
AN - OPUS4-63029
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Omar, Hassan
A1 - Ahmadi, Shayan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
T1 - Molecular Mobility of Thin Films of Poly (bisphenol-A carbonate) Capped and with one Free Surface: From Bulk-like Samples down to the Adsorbed Layer
N2 - The molecular mobility of thin films of poly(bisphenol A carbonate) (PBAC) was systematically investigated using broadband dielectric spectroscopy, employing two distinct electrode configurations. First, films were prepared in a capped geometry between aluminum electrodes employing a crossed electrode capacitor (CEC) configuration, down to film thicknesses of 40 nm. The Vogel temperature, derived from the temperature dependence of relaxation rate of the α-relaxation, increases with decreasing film thickness characterized by an onset thickness. The onset thickness depends on the annealing conditions, with less intense annealing yielding a lower onset thickness. Additionally, a broadening of the β-relaxation peak was observed with decreasing thickness, attributed to the interaction of phenyl groups with thermally evaporated aluminum, resulting in a shift of certain relaxation modes to higher temperatures relative to the bulk material. A novel phenomenon, termed the slow Arrhenius process (SAP), was also identified in proximity to the α-relaxation temperature.
For films with thicknesses below 40 nm, nanostructured electrodes (NSE) were utilized, incorporating nanostructured silica spacers to establish a free surface with air. This free surface causes an enhancement in the molecular mobility for the 40 nm sample, preserving the β-relaxation as a distinct peak. The α-relaxation was detectable in the dielectric loss down to 18 nm, shifting to higher temperatures as film thickness is decreased. Notably, the onset thickness for the increase in Vogel temperature was lower in the NSE configuration compared to the CEC setup, attributed to the presence of the polymer-air interface.
KW - Thin polymer films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623422
DO - https://doi.org/10.1039/d4sm01238k
SN - 1744-6848
VL - 21
IS - 2
SP - 241
EP - 254
PB - RSC
AN - OPUS4-62342
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, Q.
A1 - Szymoniak, Paulina
A1 - Kolmangadi, Mohamed A.
A1 - Yang, Z.
A1 - Wang, S.
A1 - Gao, Y.
A1 - Shang, J.
A1 - Hunger, J.
A1 - Aldiyarov, A.
A1 - Schönhals, Andreas
A1 - Ge, Y.
A1 - Qi, Z.
T1 - Molecular engineering of supramolecular polymer adhesive with confined water and a single crown ether
N2 - Here, we report a water-induced supramolecular polymer built from confined structural water and an intrinsic amphiphilic macrocyclic self-assembly in a nanophase separated structure. The newly designed crown ether macrocycle, featuring strong hydrophilic hydrogen bonding receptor selenoxide and a synergistical hydrophobic selenium-substituted crown core, confines the structural water in a segregated, interdigitated architecture. Although water molecules typically freeze around 0 °C, the confined structural water in this supramolecular polymer remains in a liquid-like state down to 80 °C. Previous studies suggest that multiple crown ether units are needed to generate structural water. However, here, one unit is sufficient to control the formation and disappearance of structural water and consequent supramolecular polymerization. Typically, the DC conductivity of water shows Arrhenius temperature dependency (lnσDC ∝ 1/T). In contrast, this new crown unit maintains water in confined states, which exhibit a Vogel/Fulcher/Tammann behavior (lnσDC ∝ 1/(T-T0)) at temperatures above the glass transition temperature. Moreover, this water-induced supramolecular polymer exhibits remarkable adhesion properties to hydrophilic surfaces and maintains tough adhesion at low temperatures. These findings show how a single small macrocycle can govern the complex structure and functionality of water in supramolecular systems.
KW - Supramolecular polymerization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623631
DO - https://doi.org/10.1039/D4SC06771A
SN - 2041-6539
VL - 16
SP - 1
EP - 9
PB - RSC
AN - OPUS4-62363
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Haug, T. C. V.
A1 - Fröba, M.
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Molecular fluctuations in mixed-metal MOF-74: influence of the metal composition
N2 - A selected series of metal–organic frameworks M-MOF-74 (M = Mg, Co, Ni) and mixed metal MM-MOF-74 (Mg/Co or Mg/Ni) with different compositions of metal atoms have been prepared and further investigated by broadband dielectric spectroscopy (BDS) in a wide temperature range. The dielectric spectra show at least two relaxation processes. Process-A is observed only for the Ni-containing MOFs and is attributed to localized fluctuations of the metal oxide corners. Relaxation processes-B and -C are observed for all prepared MOFs, except that process-B is not observed for Ni-MOF-74. Large-angle fluctuations such as free rotations of the linkers can be excluded due to the structure of MOF-74, but small-angle fluctuations such as torsions are possible. According to numerical simulations carried out for MOF-74, process-B can be attributed to inward and outward fluctuations of the linkers relative to the pore center.
Process-C is related to small-angle rotational fluctuations of the linker together with co-rotations of the metal nodes. The latter interpretation is supported by the dependence of the activation energy of the relaxation rate of process-C on the metal composition of the MOFs, which is discussed in terms of the bond lengths between the metal atoms and the linker which decrease in the sequence Mg, Co and Ni.
KW - Metal Organic Frameworks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639378
DO - https://doi.org/10.1039/d5ra05357a
SN - 2046-2069
VL - 15
IS - 35
SP - 29109
EP - 29118
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dong, S.
A1 - Leng, J.
A1 - Feng, Y.
A1 - Liu, M.
A1 - Stackhouse, C. J.
A1 - Schönhals, Andreas
A1 - Chiappisi, L.
A1 - Gao, L.
A1 - Chen, W.
A1 - Shang, J.
A1 - Jin, L.
A1 - Qi, Z.
A1 - Schalley, C. A.
T1 - Structural water as an essential comonomer in supramolecular polymerization
N2 - Although the concept of structural water that is bound inside hydrophobic pockets and helps to stabilize protein structures is well established, water has rarely found a similar role in supramolecular polymers. Water is often used as a solvent for supramolecular polymerization, however without taking the role of a comonomer for the supramolecular polymer structure. We report a low–molecular weight monomer whose supramolecular polymerization is triggered by the incorporation of water. The presence of water molecules as comonomers is essential to the polymerization process. The supramolecular polymeric material exhibits strong adhesion to surfaces, such as glass and paper. It can be used as a water-activated glue, which can be released at higher temperatures and reused many times without losing its performance.
KW - Supra molecular polymerization
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-432728
DO - https://doi.org/10.1126/sciadv.aao0900
SN - 2375-2548
VL - 3
IS - 11
SP - eaao0900, 1
EP - eaao0900, 8
PB - American Association for the Advancement of Science
AN - OPUS4-43272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, Christina
A1 - Zorn, R.
A1 - Emmerling, Franziska
A1 - Falkenhagen, Jana
A1 - Frick, B.
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Vibrational density of states of triphenylene based discotic liquid crystals: dependence on the length of the alkyl chain
N2 - The vibrational density of states of a series of homologous triphenylene-based discotic liquid crystals HATn (n = 5, 6, 8, 10, 12) depending on the length of the aliphatic side chain is investigated by means of inelastic neutron scattering. All studied materials have a plastic crystalline phase at low temperatures, followed by a hexagonally ordered liquid crystalline phase at higher temperatures and a quasi isotropic phase at the highest temperatures. The X-ray scattering pattern for the plastic crystalline phase of all materials shows a sharp Bragg reflection corresponding to the intercolumnar distance in the lower q-range and a peak at circa 17 nm-1 related to intracolumnar distances between the cores perpendicular to the columns as well as a broad amorphous halo related to the disordered structure of the methylene groups in the side chains in the higher q-range. The intercolumnar distance increases linearly with increasing chain length for the hexagonal columnar ordered liquid crystalline phase. A similar behaviour is assumed for the plastic crystalline phase. Besides n = 8 all materials under study exhibit a Boson peak. With increasing chain length, the frequency of the Boson peak decreases and its intensity increases. This can be explained by a self-organized confinement model. The peaks for n = 10, 12 are much narrower than for n = 5, 6 which might imply the transformation from a rigid system to a softer one with increasing chain length. Moreover the results can also be discussed in the framework of a transition from an uncorrelated to a correlated disorder with increasing n where n = 8 might be speculatively considered as a transitional state.
KW - X-ray scattering
KW - Neutron scattering
KW - Differential scanning calorimetry
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-304789
DO - https://doi.org/10.1039/c3cp55303e
SN - 1463-9076
SN - 1463-9084
VL - 16
IS - 16
SP - 7324
EP - 7333
PB - The Royal Soc. of Chemistry
CY - Cambridge
AN - OPUS4-30478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gramse, G.
A1 - Schönhals, Andreas
A1 - Kienberger, F.
T1 - Nanoscale dipole dynamics of protein membranes studied by broadband dielectric microscopy
N2 - We investigate the nearfield dipole mobility of protein membranes in a wide frequency range from 3 kHz to 10 GHz. The results of our nanoscale dielectric images and spectra of bacteriorhodopsin (bR) reveal Debye relaxations with time constants of τ ∼ 2 ns and τ ∼ 100 ns being characteristic of the Dipole moments of the bR retinal and α-helices, respectively. However, the dipole mobility and therefore the protein biophysical function depend critically on the amount of surface water surrounding the protein, and the characteristic mobility in the secondary structure is only observed for humidity levels <30%. Our results have been achieved by adding the frequency as a second fundamental dimension to quantitative dielectric microscopy. The key elements for the success of this advanced technique are the employed heterodyne detection scheme, the broadband electrical signal source, a high frequency optimized cabling, development of calibration procedures and precise finite element modelling. Our study demonstrates the exciting possibilities of broadband dielectric microscopy for the investigation of dynamic processes in cell bioelectricity at the individual molecular level. Furthermore, the technique may shed light on local dynamic processes in related materials science applications like semiconductor Research or nano-electronics.
KW - Broadband dielectric microscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475230
DO - https://doi.org/10.1039/c8nr05880f
SN - 2040-3372
VL - 11
IS - 10
SP - 4303
EP - 4309
PB - RSC
AN - OPUS4-47523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, Christina
A1 - Zorn, R.
A1 - Frick, B.
A1 - Schönhals, Andreas
T1 - Quasi- and inelastic neutron scattering to investigate the molecular dynamics of discotic molecules in the bulk
N2 - In- and quasielastic neutron scattering is employed to investigate both the vibrational density of states and the molecular dynamics of two homologous discotic liquid crystals (DLC) with different length of the alkyl side chain based on a triphenylene derivate. For both compounds characteristic low frequency excess contributions to the vibrational density of states are found. Therefore it is concluded that these liquid crystals show a glass-like behaviour. Elastic scans further show that in these materials a rich molecular dynamics takes place.
T2 - QENS/WINS 2014 - 11th International Conference on Quasielastic Neutron Scattering and 6th International Workshop on Inelastic Neutron Spectrometers
CY - Autrans, France
DA - 2014-05-11
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-325477
DO - https://doi.org/10.1051/epjconf/20158302017
SN - 2100-014X
VL - 83
SP - 02017-1
EP - 02017-4
PB - EDP Sciences
CY - Les Ulis
AN - OPUS4-32547
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Junias, Josua Kondja
A1 - Askar, Enis
A1 - Shaanika, Erasmus
A1 - Holtappels, Kai
A1 - Thewis, Max
A1 - Liebner, Christian
T1 - Hydrogen Mixtures Flammability Limits Prediction Using Machine Learning Models
N2 - Predictions on flammability limits (FLs) had been conducted using semi-empirical and fully empirical models, which are either limited in scope of application and/or affected by significant methodical prediction errors. Some parameters influencing the FLs are not considered in the non-comprehensive empirical models. In the present study, optimized multilayer perceptron (MLP) models are investigated to improve the accuracy of the prediction of FLs in dependance from the temperature and any inert gas admixtures. Different input features constituted by the flammability state, mixture composition, initial mixture temperature, adiabatic flame temperature, and Lewis numbers were implemented into the MLP model. Data limitation challenges were addressed using data augmentation. The best model indicated averaged deviations comparable to the respective experimental FLs determination errors. The models also indicated comparable performances in comparison to the empirical models while having a broader range of applicability. This approach seeks to improve FLs prediction accuracy and calculation time necessary, minimizing FLs determination experimental efforts.
KW - Machine Learning
KW - Flammability Limits
KW - Hydrogen mixtures
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658583
DO - https://doi.org/10.58895/hysafe.58
VL - 3
IS - 1
SP - 84
EP - 96
PB - KIT Scientific Publishing
CY - Karlsruhe
AN - OPUS4-65858
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Huang, J.
A1 - Mosane Razavi, Negar
A1 - Bojdys, M. J.
A1 - Forster, A. B.
A1 - Budd, P. M.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Molecular Mobility and Gas Transport Properties of Mixed Matrix Membranes Based on PIM‑1 and a Phosphinine Containing Covalent Organic Framework
N2 - Polymers with intrinsic microporosity (PIMs) are gaining attention as gas separation membranes. Nevertheless, they face limitations due to pronounced physical aging. In this study a covalent organic framework containing λ5-phosphinine moieties, CPSF-EtO were incorporated as a nanofiller (concentration range 0-10 wt%) into a PIM-1 matrix forming dense films with a thickness of ca. 100 μm. The aim of the investigation was to investigate possible enhancements of gas transport properties and mitigating effects on physical aging. The incorporation of the nanofiller occurred on aggregate level with domains up to 100 nm as observed by T-SEM and confirmed by X-ray scattering. Moreover, the X-ray data show that the structure of the microporous network of the PIM-1 matrix is changed by the nanofiller.
As the molecular mobility is fundamental for gas transport as well as for physical aging, the study includes dielectric investigations of pure PIM-1 and PIM-1/CPSF-EtO mixed matrix membranes to establish a correlation between the molecular mobility and the gas transport properties. Using the time-lag method the gas permeability and the permselectivity were determined for N2, O2, CH4 and CO2 for samples with variation in filler content. A significant increase in the permeability of CH4 and CO2 (50 % increase compared to pure PIM-1) was observed for a concentration of 5 wt% of the nanofiller. Furthermore, the most pronounced change in the permselectivity was found for the gas pair CO2/N2 at a filler concentration of 7 wt%.
KW - Polymers of Intrinsic Microporosity
KW - Nanocomposites
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595031
DO - https://doi.org/10.1021/acs.macromol.3c02419
SN - 0024-9297
VL - 57
IS - 4
SP - 1829
EP - 1845
PB - ACS Publications
AN - OPUS4-59503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waniek, Tassilo
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
T1 - The influence of water released from particles in epoxy‐based nanocomposites
N2 - AbstractRecent studies have hypothesized that the reinforcing effects of boehmite nanoparticles (BNPs) in polymer nanocomposites (PNCs) are partly related to the particles themselves and partly to the water released from the BNP during curing. In this work, PNCs made from dried BNP (dBNP) with concentrations up to 15 wt% are investigated to differentiate particle and water related effects. The observed trend of the storage modulus in dynamic mechanical thermal analysis measurements was found to be independent of the drying procedure. Stiffness maps from intermodulation atomic force microscopy showed that dBNP leads to a stiffening of the interphase surrounding the particles compared with the unaffected epoxy matrix, while a softer interphase was reported for PNCs with as received BNP. A slight decrease in the glass transition temperature was observed by broadband dielectric spectroscopy related to a lowered crosslink density due to the particles. A significantly higher decrease was reported for PNCs with BNP, attributed to water influencing the curing process. In conclusion, the stiffening of PNC with BNP is related to the particles themselves, while the release of water causes the formation of a soft interphase in the vicinity of the particles and a significant decrease in crosslink density.
KW - AFM stiffness of interface
KW - Aluminium oxide hydroxide
KW - Boehmit nanoparticle
KW - Glass transition temperature
KW - Broadband dielectric spectroscopy
KW - Crosslink density control
KW - Structure–property relationship
KW - Nanocomposites
KW - Thermoset
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606772
DO - https://doi.org/10.1002/app.55937
SN - 0021-8995
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-60677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fahmy, Alaa
A1 - Omar, Hassan
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Friedrich, J.
T1 - Structure of plasma deposited acrylic acid‐allyl alcohol copolymers
N2 - Copolymer thin films with two types of functional groups have excellent performance as sensors, for example. The formation and deposition of allyl alcohol‐acrylic acid copolymer films by pulsed high frequency plasma is a complex process. As usual, the chemical composition of the top surface of the films was investigated by XPS and FTIR measurements. Furthermore, contact angle measurements with water were used to characterise the hydrophilicity and wettability of the polymer films.
After plasma deposition, a significant decrease in functional groups (OH and COOH) was observed compared to the classically copolymerised equivalent.
The remaining functional groups, i.e. the majority of these groups, were sufficient for application as sensor layers. Segmental mobility and conductivity, important for sensor applications, were analysed by broadband dielectric spectroscopy.
KW - Plasma Polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578349
DO - https://doi.org/10.1002/ppap.202300071
SN - 1612-8850
SP - 1
EP - 14
PB - Wiley online library
AN - OPUS4-57834
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Auersch, Lutz
T1 - Railway vibration – fast physics-based models for the prediction of ground vibration and the identification of track damage
N2 - The following applications of machine learning will be discussed:
1. The prediction of the wave propagation from a railway line (completely physics based for surface lines, physics-based machine learning for tunnel lines)
2. The track behaviour for the emission of train-induced ground vibration (physics based for homogeneous soil, machine learning for layered soil)
3. Track damage detection and quantification from frequency response functions and moving load responses
4. Bridge damage detection and localisation from modal analysis and moving load
5. The use of axle-box acceleration for the identification of track/sub-soil condition and bridge resonances.
The prediction of railway vibration usually needs time-consuming finite element, boundary element and wavenumber domain calculations. For a user-friendly prediction software however, fast calculations are needed. Several time-consuming detailed calculations have been used to develop simpler and fast models for the surface railway lines. The more challenging prediction from tunnel lines will be attacked by purely mathematical and by physics-informed machine learning. The dynamic stiffnesses of isolated or un-isolated railway tracks from detailed calculations with a continuous soil have been approximated with the simpler Winkler soil. The vehicle-track resonance (P2 resonance) rules the effect of the mitigation measures, and it can also be used for the on-board monitoring of the track and sub-soil condition. For the identification of track damage such as gaps between sleepers, track slabs and layers, detailed models with a continuous soil have been updated to get the best fit to the measured frequency response functions from hammer tests and the deformation pattern from the moving load response. Whereas the track damage can be locally identified, this is more difficult for bridges where the modal analysis gives mainly global information. The influence lines of the inclination for statically passing vehicles (locomotive, truck, compaction roller) have been used to localise bridge damage (stiffness variations). The on-board monitoring of rail bridges needs special conditions (regular trains with special speeds) to excite and measure the bridge resonance.
T2 - 11th European Workshop on Structural Health Monitoring (EWSHM 2024)
CY - Potsdam, Germany
DA - 10.06.2024
KW - Vibration prediction
KW - Track damage detection
KW - Human and machine learning
KW - Wave propagation
KW - Surface line
KW - Tunnel
KW - Bridge resonance
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612462
DO - https://doi.org/10.58286/29865
SN - 1435-4934
VL - 29
IS - 7
SP - 1
EP - 9
PB - NDT.net
CY - Kirchwald
AN - OPUS4-61246
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breßler, Ingo
A1 - Kohlbrecher, J.
A1 - Thünemann, Andreas
T1 - SASfit: a tool for small-angle scattering data analysis using a library of analytical expressions
N2 - SASfit is one of the mature programs for small-angle scattering data analysis and has been available for many years. This article describes the basic data processing and analysis workflow along with recent developments in the SASfit program package (version 0.94.6). They include (i) advanced algorithms for reduction of oversampled data sets, (ii) improved confidence assessment in the optimized model parameters and (iii) a flexible plug-in system for custom user-provided models. A scattering function of a mass fractal model of branched polymers in solution is provided as an example for implementing a plug-in. The new SASfit release is available for major platforms such as Windows, Linux and MacOS. To facilitate usage, it includes comprehensive indexed documentation as well as a web-based wiki for peer collaboration and online videos demonstrating basic usage. The use of SASfit is illustrated by interpretation of the small-angle X-ray scattering curves of monomodal gold nanoparticles (NIST reference material 8011) and bimodal silica nanoparticles (EU reference material ERM-FD-102).
KW - Small-angle X-ray scattering
KW - Small-angle neutron scattering
KW - Curve fitting
KW - Nanotechnology
KW - Nanoparticles
KW - Polymers
KW - SAXS
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343348
DO - https://doi.org/10.1107/S1600576715016544
SN - 0021-8898
SN - 1600-5767
VL - 48
SP - 1587
EP - 1598
PB - Blackwell
CY - Oxford
AN - OPUS4-34334
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Breßler, Ingo
A1 - Pauw, Brian Richard
A1 - Thünemann, Andreas
T1 - McSAS: software for the retrieval of model parameter distributions from scattering patterns
N2 - A user-friendly open-source Monte Carlo regression package (McSAS) is presented, which structures the analysis of small-angle scattering (SAS) using uncorrelated shape-similar particles (or scattering contributions). The underdetermined problem is solvable, provided that sufficient external information is available. Based on this, the user picks a scatterer contribution model (or 'shape') from a comprehensive library and defines variation intervals of its model parameters. A multitude of scattering contribution models are included, including prolate and oblate nanoparticles, core-shell objects, several polymer models, and a model for densely packed spheres. Most importantly, the form-free Monte Carlo nature of McSAS means it is not necessary to provide further restrictions on the mathematical form of the parameter distribution; without prior knowledge, McSAS is able to extract complex multimodal or odd-shaped parameter distributions from SAS data. When provided with data on an absolute scale with reasonable uncertainty estimates, the software outputs model parameter distributions in absolute volume fraction, and provides the modes of the distribution (e.g. mean, variance etc.). In addition to facilitating the evaluation of (series of) SAS curves, McSAS also helps in assessing the significance of the results through the addition of uncertainty estimates to the result. The McSAS software can be integrated as part of an automated reduction and analysis procedure in laboratory instruments or at synchrotron beamlines.
KW - Nanotechnology
KW - Nanoparticles
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-334396
DO - https://doi.org/10.1107/S1600576715007347
SN - 0021-8898
SN - 1600-5767
VL - 48
IS - 3
SP - 962
EP - 969
PB - Blackwell
CY - Oxford
AN - OPUS4-33439
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kohlbrecher, J.
A1 - Breßler, Ingo
T1 - Updates in SASfit for fitting analytical expressions and numerical models to small-angle scattering patterns
N2 - Small-angle scattering is an increasingly common method for characterizing particle ensembles in a wide variety of sample types and for diverse areas of application. SASfit has been one of the most comprehensive and flexible curve-fitting programs for decades, with many specialized tools for various fields. Here, a selection of enhancements and additions to the SASfit program are presented that may be of great benefit to interested and advanced users alike: (a) further development of the technical basis of the program, such as new numerical algorithms currently in use, a continuous integration practice for automated building and packaging of the software, and upgrades on the plug-in system for easier adoption by third-party developers; (b) a selection of new form factors for anisotropic scattering patterns and updates to existing form factors to account for multiple scattering effects; (c) a new type of a very flexible distribution called metalog [Keelin (2016). Decis. Anal. 13, 243–277], and regularization techniques such as the expectation-maximization method [Dempster et al. (1977). J. R. Stat. Soc. Ser. B (Methodological), 39, 1–22; Richardson (1972) J. Opt. Soc. Am. 62, 55; Lucy (1974). Astron. J. 79, 745; Lucy (1994). Astron. Astrophys. 289, 983–994], which is compared with fits of analytical size distributions via the non-linear least-squares method; and (d) new structure factors, especially for ordered nano- and meso-scaled material systems, as well as the Ornstein–Zernike solver for numerical determination of particle interactions and the resulting structure factor when no analytical solution is available, with the aim of incorporating its effects into the small-angle scattering intensity model used for fitting with SASfit.
KW - Small-angle scattering
KW - Numerical models
KW - Structure factors
KW - Regularization
KW - SAXS
KW - SANS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565069
DO - https://doi.org/10.1107/S1600576722009037
SN - 0021-8898
SN - 1600-5767
VL - 55
IS - 6
SP - 1677
EP - 1688
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-56506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernal, S. A.
A1 - Angst, U. M.
A1 - Provis, J. L.
A1 - Thiel, C.
A1 - Gluth, Gregor
A1 - Villagran-Zaccardi, Y.
A1 - De Belie, N.
T1 - Recommendation of RILEM TC 281-CCC: RILEM CPC-18R1—guideline for measuring the carbonation depth of hardened concrete using a pH indicator solution
N2 - This recommendation provides a procedure for determining the carbonation depth on the surface of concrete by applying a pH indicator. This includes definitions of carbonation, carbonation depth and carbonation front, as well as descriptions of the different pH indicator solutions that can be used. Recommendations for testing laboratory-prepared specimens and those obtained from concrete structures are also given. This involves guidelines for sample preparation and/or extraction, CO2 exposure duration, carbonation depth determination and reporting of results. A section on data interpretation is also provided, as carbonation results are used for determining durability of concrete, as well as a criterion for materials selection or for carbon uptake calculations. The new Recommendation CPC-18R1 is intended to supersede the former RILEM recommendation CPC-18, particularly when prescribed as the preferred method for evaluating and reporting carbonation depths.
KW - Carbonation
KW - Concrete
KW - pH indicator
KW - Phenolphthalein
KW - Testing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656191
DO - https://doi.org/10.1617/s11527-026-02966-0
SN - 1359-5997
SN - 1871-6873
VL - 59
IS - 3
SP - 1
EP - 11
PB - Springer Nature
AN - OPUS4-65619
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholl, Juliane
A1 - Scharpmann, Philippa
A1 - Bagheri, Abbas
A1 - Lisec, Jan
A1 - Meiers, Emelie
A1 - Jaeger, Carsten
A1 - Leonhardt, Robert
A1 - Haase, Hajo
A1 - Koch, Matthias
T1 - Beyond the lab: Real-world composition of commercial Li-ion battery electrolytes
N2 - This study presents a systematic, characterization of electrolytes from commercial lithium-ion batteries (LIB), encompassing 90 batteries from leading global manufacturers across diverse formats and application sectors. An integrated, complementary mass spectrometric workflow combining LC–MS/MS, GC–MS, and high-resolution MS was employed. To ensure robust structural annotation, molecular identifications were assigned confidence levels following Schymanski et al. (2014).
Across all formats, PF6− was confirmed as the dominant Li+ counterion, frequently coexisting with BF4−, PO2F2−, and bis(fluorosulfonyl)imide (FSI−), forming binary and ternary salt systems optimized for both conductivity and safety. Solvent systems revealed the widespread use of propylene carbonate (PC) combined with diverse carbonate mixtures, demonstrating trends in performance optimization specific to cell format. A variety of additives were identified, reflecting a clear shift towards multifunctional, synergistic additive packages and the gradual replacement of fluorinated species with environmentally safer alternatives. Cycling studies demonstrated that electrolyte degradation mechanisms are strongly influenced by electrode composition and additive chemistry, with oxidative degradation pathways dominating.
Together, these findings provide rare empirical insight into the evolving formulation strategies of electrolytes in commercial LIB, still employing classic carbonates and LiPF6, but highlighting a trend toward safer, more robust, and sustainable electrolyte architectures by using synergistic multifunctional systems.
KW - Mass Spectrometry
KW - Lithium-ion batteries
KW - Electrolyte degradation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656254
DO - https://doi.org/10.1016/j.jpowsour.2026.239739
SN - 0378-7753
VL - 673
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-65625
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diehn, S.
A1 - Zimmermann, B.
A1 - Tafintseva, V.
A1 - Seifert, S.
A1 - Bagcioglu, M.
A1 - Ohlson, M.
A1 - Weidner, Steffen
A1 - Fjellheim, S.
A1 - Kohler, A.
A1 - Kneipp, Janina
T1 - Combining Chemical Information From Grass Pollen in Multimodal Characterization
N2 - The analysis of pollen chemical composition is important to many fields, including agriculture, plant physiology, ecology, allergology, and climate studies. Here, the potential of a combination of different spectroscopic and spectrometric methods regarding the characterization of small biochemical differences between pollen samples was evaluated using multivariate statistical approaches. Pollen samples, collected from three populations of the grass Poa alpina, were analyzed using Fourier-transform infrared (FTIR) spectroscopy, Raman spectroscopy, surface enhanced Raman scattering (SERS), and matrix assisted laser desorption/ionization mass spectrometry (MALDI-TOF MS). The variation in the sample set can be described in a hierarchical framework comprising three populations of the same grass species and four different growth conditions of the parent plants for each of the populations. Therefore, the data set can work here as a model system to evaluate the classification and characterization ability of the different spectroscopic and spectrometric methods. ANOVA Simultaneous Component Analysis (ASCA) was applied to achieve a separation of different sources of variance in the complex sample set. Since the chosen methods and sample preparations probe different parts and/or molecular constituents of the pollen grains, complementary information about the chemical composition of the pollen can be obtained. By using consensus principal component analysis (CPCA), data from the different methods are linked together. This enables an investigation of the underlying global information, since complementary chemical data are combined. The molecular information from four spectroscopies was combined with phenotypical information gathered from the parent plants, thereby helping to potentially link pollen chemistry to other biotic and abiotic parameters.
KW - Pollen
KW - MALDI-TOF MS
KW - FTIR
KW - Raman
KW - Multivariate analyses
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504822
DO - https://doi.org/10.3389/fpls.2019.01788
VL - 10
SP - 1788
AN - OPUS4-50482
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - The Ring-Opening Polymerisation-Polycondensation (ROPPOC) Approach to cyclic Polymers
N2 - A new concept called “Ring-Opening Polymerization (ROP) combined with simultaneous POlyCondensation” (ROPPOC) is presented and discussed. This synthetic strategy is based on the intermediate formation of chains having two end groups that can react with each other. The ROPPOC syntheses are subdivided into three groups according to the nature of the chain ends: two ionic end groups, one ionic and one covalent chain end and a combination of two reactive covalent end groups may be involved, depending on the catalyst. The usefulness for the preparation of cyclic polymers is discussed with a review of numerous previously published examples. These examples concern to following classes of cyclic polymers: polypeptides, polyamides, polyesters, including polycarbonates, and cyclic polysiloxanes. It is demonstrated, that the results of certain ROPPOC syntheses are in contradiction to the Jacobson-Stockmayer theory. Finally, the usefulness of ROPPOCs for the detection of polydisperse catenanes is discussed.
KW - Ring-opening Polymerisation
KW - MALDI-TOF MS
KW - ROPPOC
KW - Cyclic
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508509
DO - https://doi.org/10.1002/marc.202000152
SP - 2000152
PB - Wiley
AN - OPUS4-50850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - High Tm poly(L-lactide)s via REP or ROPPOC of L-lactide
N2 - A new kind of high melting (HTm) pol(L-lactide) was discovered when cyclic poly(L-lactide)s were prepared by ring-expansion polymerization with cyclic tin catalysts at 130–160 °C in bulk. By DSC measurements with 10 K min−1 melting temperatures (Tm) in the range of 190–196 °C were found. The WAXS and SAXS measurements evidenced that not a new crystal lattice but a well-ordered morphology and a higher perfection of the crystallites are responsible for the high Tm values and high crystallinities. Under identical reaction conditions SnOct2-catalyzed and alcohol-initiated ROPs do not yield these crystallites.
Furthermore, it was found that the standard crystallites are kinetically favored upon rapid crystallization, whereas the high melting form of poly(L-lactide) is thermodynamically more stable.
KW - Polylactide
KW - MALDI-TOF MS
KW - ROPPOC
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507477
DO - https://doi.org/10.1039/c9py01908a
VL - 11
IS - 12
SP - 2182
EP - 2193
PB - Royal Society of Chemistry
AN - OPUS4-50747
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Chatti, S.
A1 - Kricheldorf, H. R.
T1 - About the transformation of low Tm into high Tm poly(L-lactide)s by annealing under the influence of transesterification catalysts
N2 - Cyclic polylactides were prepared in bulk at 170 °C, crystallized at 120 °C and then annealed at temperatures between 130 and 170 C with variation of catalyst, catalyst concentration and annealing time. The transformation of the initially formed low melting (LTm) crystallites, having melting temperatures (Tm) <180 °C into high melting (HTm) crystallites having Tm values > 189 °C was monitored by means of DSC measurements and characterized in selected cases by SAXS measurements. It was confirmed that the formation of HTm crystallites involves a significant growth of the thickness of the lamellar crystallites along with smoothing of their surface. Annealing at 170 °C for 1 d or longer causes thermal degradation with lowering of the molecular weights, a gradual transition of cyclic into linear chains and a moderate decrease of lamellar thickness. An unexpected result revealed by MALDI TOF mass spectrometry is a partial reorganization of the molecular weight distribution driven by a gain of crystallization enthalpy.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystallization
KW - Annealing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521062
DO - https://doi.org/10.1039/d0ra10012a
VL - 11
IS - 5
SP - 2872
EP - 2883
PB - Royal Society of Chemistry
AN - OPUS4-52106
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Polymerization of L-lactide with SnCl2: A Low Toxic and Eco-friendly Catalyst
N2 - Polymerizations of L-lactide catalyzed either by neat SnCl2 or by SnCl2 + difunctional cocatalysts were conducted in bulk at 180, 160 and 140 °C with variation of the Lac/Cat ratio and time. With neat SnCl2 poly(L-lactide) having weight average molecular weights (uncorrected Mw’s) up to 190 000 g mol−1 were obtained mainly consisting of linear chains. Addition of salicylic acid or 1,1-bisphenol yielded a higher fraction of cyclic polylactides but lower molecular weights. Furthermore, SnCl2 was compared with Bu2SnCl2 and various other metal chlorides and the best results were obtained with SnCl2. With ethyl L-lactate as initiator SnCl2-catalyzed ROPs were performed at 120 °C and the lac/initiator ratio was varied. All these experiments were conducted under conditions allowing for comparison with ROPs catalyzed with neat Sn(II)-2-ethyhexanoate. Such a comparison was also performed with ε-caprolactone as monomer.
KW - Catalyst
KW - Polylactide
KW - MALDI-TOF MS
KW - Polycondensation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520517
DO - https://doi.org/10.1007/s10924-020-02042-w
SN - 1566-2543
SP - 1
EP - 13
PB - Springer Nature
AN - OPUS4-52051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - High molecular weight poly(l-lactide) via ring-opening polymerization with bismuth subsalicylate-The role of cocatalysts
N2 - The catalytic potential of bismuth subsalicylate (BiSub), a commercial drug, for ring-opening polymerization (ROP) of L-lactide was explored by variation of co-catalyst and polymerization time. Various monofunctional phenols or carboxylic acids, aromatic ortho-hydroxy acids and diphenols were examined as potential co-catalysts. 2,2´-Dihydroxybiphenyl proved to be the most successful co-catalyst yielding weight average molecular weights (uncorrected Mw values up to 185 000) after optimization of reaction time and temperature. Prolonged heating (>1-2h) depending on catalyst concentration) caused thermal degradation. In polymerization experiments with various commercial Bi(III) salts a better alternative to BiSub was not found. By means of matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry a couple of unusual and unexpected transesterification reactions were discovered. Finally, the effectiveness of several antioxidants and potential catalyst poisons was explored, and triphenylphosphine was found to be an effective catalyst poison.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-opening polymerization
KW - Bismuth
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519513
DO - https://doi.org/10.1002/app.50394
SN - 0021-8995
VL - 138
IS - 19
SP - 50394
PB - Wiley
AN - OPUS4-51951
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - ROP of L-lactide and ε-caprolactone catalyzed by tin(ii) and tin(iv) acetates–switching from COOH terminated linear chains to cycles
N2 - The catalytic potential of tin(II)acetate, tin(IV)acetate, dibutyltin-bis-acetate and dioctyl tin-bis-acetate was compared based on polymerizations of L-lactide conducted in bulk at 160 or 130C. With SnAc2 low-Lac/Cat ratios (15/1–50/1) were studied and linear chains having one acetate and one carboxyl end group almost free of cyclics were obtained. Higher monomer/catalyst ratios and lower temperatures favored formation of cycles that reached weight average molecular weights (Mw's) between 100,000 and 2,500,000. SnAc4 yielded mixtures of cycles and linear species under all reaction conditions. Dibutyltin- and dioctyl tin bis-acetate yielded cyclic polylactides under most reaction conditions with Mw's in the range of 20,000–80,000. Ring-opening polymerizations performed with ε-caprolactone showed similar trends, but the formation of COOH-terminated linear chains was significantly more favored compared to analogous experiments with lactide. The reactivity of the acetate catalysts decreased in the following order: SnAc2> SnAc4>Bu2SnAc2 Oct2SnAc2.
KW - Catalyst
KW - MALDI-TOF MS
KW - Ring-opening polymerization
KW - Tin acetates
KW - Polylactide
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520831
DO - https://doi.org/10.1002/pol.20200866
SP - 1
EP - 12
PB - Wiley Online Library
AN - OPUS4-52083
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Kricheldorf, H. R.
A1 - Scheliga, F.
T1 - Ring-expansion copolymerization of L-lactide and glycolide
N2 - 1:1 Copolymerizations of glycolide (GL) and L-lactide (LA) is performed in bulk at 100°C and at 160°C with four cyclic tin catalysts. The resulting copolyesters are characterized by SEC measurements, 1H and 13C NMR spectroscopy and by MALDI TOF mass spectrometry. At 160°C and longer reaction time (22 h) nearly complete conversion of both monomers is achieved, and cyclic copolymers with nearly random sequences are formed. At shorter times (0.5-3.0 h, depending on catalyst) the conversion of LA is incomplete, and only cyclics having even numbers of lactyl units are obtained. At 100°C at 22 h again cycles mainly consisting of even numbered lactyl units are formed, but with even and odd numbers of glycolyl units. Copolymerization of lactide at 160°C with small amounts of GL show that formation of high Tm crystallites (Tm > 190°C) is hindered even when only > 2% of GL is added. For polyglycolide containing a smaller amount of lactide complete solubility in hexafluoroisopropanol is only observed around and above 20 mol% of lactide.
KW - Ring-expansion polymerization
KW - Copolymerization
KW - MALDI-TOF MS
KW - L-lactide
KW - Glycolide
KW - Crystallization
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520270
DO - https://doi.org/10.1002/macp.202000307
SN - 1022-1352
VL - 22
IS - 3
SP - 307
PB - WileyVCH
AN - OPUS4-52027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Reply to the comment on “synthesis of cyclic polymers and flaws of the Jacobson-Stockmayer theory” by R. Szymanski
N2 - In a recent publication the authors have presented theoretical and experimental results indicating that the Jacobson–Stockmayer (JS) theory does not provide a correct description of reversible polycondensations for all polymers and for high conversions (e.g. polycondensation in bulk). In this context reversibility means that all condensation step whether resulting in chain growth or in cyclization are reversible and thus, part of an equilibrium. The first two sections of that paper were focused on the demonstration that small, and above all, large cycles can be formed by end-to-end (ete) cyclization in reversible like in irreversible polycondensations. A significant contribution of ete-cyclization to the course of reversible polycondensations was denied by J + S apparently as a contribution to Florýs dogma, that the end groups of long polymer chains will never meet.
KW - Polylactide
KW - MALDI-TOF MS
KW - Jacobsen-Stockmayer theory
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513985
DO - https://doi.org/10.1039/D0PY01118E
VL - 11
IS - 38
SP - 6226
EP - 6228
PB - Royal Society of Chemistry
AN - OPUS4-51398
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scholz, Philipp
A1 - Falkenhagen, Jana
A1 - Wachtendorf, Volker
A1 - Brüll, Robert
A1 - Simon, Franz-Georg
T1 - Investigation on the Durability of a Polypropylene Geotextile under Artificial Aging Scenarios
N2 - Geosynthetics are widely used in various civil engineering applications, such as geotextiles in coastal protection, and display a sustainable alternative to natural mineral materials. However, the full benefits of using geosynthetics can only be gained with a long service lifetime of the products. With the use of added stabilizers to the polymers, service lifetimes can be achieved in the range of 100 years. Therefore, accelerated aging methods are needed for the assessment of the long-term performance of geotextiles. In the present study, the behavior of geosynthetic materials made of polypropylene was investigated under artificial aging conditions involving elevated temperatures ranging from 30 to 80 °C, increased oxygen pressures ranging from 10 to 50 bar in water-filled autoclaves, and UV irradiation under atmospheric conditions. ATR-IR spectroscopy was employed to detect the increase in the carbonyl index over various aging durations, indicating the oxidative degradation of the geotextile. The most pronounced increase was observed in the case of aging through UV irradiation, followed by thermal aging. Elevated pressure, on the other hand, had a lower impact on oxidation. High-temperature size exclusion chromatography was utilized to follow the reduction in molar mass under different degradation conditions, and the results were consistent with those obtained from ATR-IR spectroscopy. In polyolefins such as polypropylene, Hindered Amine Stabilizers (HAS) are used to suppress oxidation caused by UV radiation. The quantitative analysis of HAS was carried out using a UV/Vis method and HPLC. The degradation of UV stabilizers during the aging of geotextiles is responsible for the oxidation and the reduction in the molar mass of polypropylene. From the results, it can be concluded that applications of PP geotextile without soil or sand cover might cause the risk of the formation of microplastic particles. Material selection, design, and maintenance of the construction must follow best practices, including the system’s removal or replacement at end-of-life. Otherwise, a sustainable use of geotextiles in civil engineering is not possible.
KW - Geotextiles
KW - Microplastic
KW - Size exclusion chromatography
KW - Accelerated aging
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599739
DO - https://doi.org/10.3390/su16093559
SN - 2071-1050
VL - 16
IS - 9
SP - 1
EP - 15
PB - MDPI AG
CY - Basel
AN - OPUS4-59973
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Choi, Ching-Yi
A1 - Lossada, F.
A1 - Walter, K.
A1 - Fleck-Kunde, T.
A1 - Behrens, S.
A1 - Meinelt, T.
A1 - Falkenhagen, Jana
A1 - Hiller, M.
A1 - Oschkinat, H.
A1 - Dallmann, A.
A1 - Taden, A.
A1 - Börner, H.G.
T1 - Organic transformation of lignin into mussel-inspired glues: next-generation 2K adhesive for setting corals under saltwater
N2 - The 2-methoxyphenol units (G-units) in lignin are modified by demethylation and oxidation to provide the activated lignin as one part of an advanced biobased two-component (2K) adhesive system, which exhibits promising shear strengths in dry and underwater applications. The activation of lignin is straightforward and generates quinones via demethylation and periodate oxidation. These act as Michael acceptors and react smoothly with multi-thiol-star polymers to yield thiol-catechol connectivities (TCCs). The mussel-inspired material platform acts as a very robust and versatile adhesive, combining low-cost and readily available lignin with multi-thiols to achieve outstanding adhesion strengths of up to 15 MPa in dry application. In particular, the 2K system is compatible with the marine biological environment and shows no acute toxicity to sensitive organisms such as fish eggs. Thus, one possible application of this material could be an adhesive for setting temperature-resistant corals in damaged reefs.
KW - Lignin modification
KW - Mussel-inspired adhesive systems
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594588
DO - https://doi.org/10.1039/d3gc03680d
SN - 1463-9270
SP - 1
EP - 15
PB - RSC
CY - Cambridge
AN - OPUS4-59458
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H.
T1 - Cyclic polyglycolides via ring-expansion polymerization with cyclic tin catalysts
N2 - Glycolide was polymerized in bulk with two cyclic catalysts − 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzepane (SnBiph). The monomer/initiator ratio, temperature (140 – 180 °C) and time (1–––4 days) were varied. The MALDI TOF mass spectra exclusively displayed peaks of cyclic polyglycolide (PGA) and revealed an unusual “saw-tooth pattern” in the mass range below m/z 2 500 suggesting formation of extended ring crystallites. The DSC measurements indicated increasing crystallinity with higher temperature and longer time, and after annealing for 4 d at 160 °C a hitherto unknown and unexpected glass transition was found in the temperature range of 170–185 °C. Linear PGAs prepared by means of metal alkoxides under identical conditions did not show the afore-mentioned features of the cyclic PGAs, neither in the mass spectra nor in the DSC measurements. All PGAs were also characterized by SAXS measurements, which revealed relatively small L-values suggesting formation of thin crystallites in all cases with little influence of the reaction conditions.
KW - Polyglycolide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Crystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595541
DO - https://doi.org/10.1016/j.eurpolymj.2024.112811
SN - 0014-3057
VL - 207
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-59554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Polycondensation of poly(L-lactide) alkyl esters combined with disproportionation and symproportionation of the chain lengths
N2 - Ring-opening polymerizations (ROPs) of l-lactide (LA) were performed with ethyl l-lactate or 11-bromoundecanol as initiators (In) and tin(II) ethyl hexanoate (SnOct2) as catalyst (Cat) using four different LA/In ratios (20/1, 40/1, 60/1, and 100/1). One series of ROPs was conducted in bulk at 120 °C, yielding PLAs with low dispersities (Ð ~ 1.2–1.4), and a second series was conducted in bulk at 160 °C, yielding higher dispersities (Ð ~ 1.3–1.9). Samples from both series were annealed for 1 or 14 days at 140 °C in the presence of SnOct2. Both polycondensation and disproportionation reactions occurred, so that all four samples tended to form the same type of molar mass distribution below 10,000 Da, regardless of their initially different number average molar masses (Mn). Both initiators gave nearly identical results. The thermodynamic control of all reversible transesterification processes favored the formation of crystallites composed of chains with a Mn around 3500–3700, corresponding to a crystal thickness of 10–13 nm.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600081
DO - https://doi.org/10.1002/pol.20240118
SN - 2642-4150
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-60008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Syntheses of high molecular mass polyglycolides via ring-opening polymerization with simultaneous polycondensation (ROPPOC) by means of tin and zinc catalysts
N2 - Glycolide was polymerized in bulk by means of four different ROPPOC catalysts: tin(II) 2-ethylhexanoate (SnOct2), dibutyltin bis(pentafluoro-phenoxide) (BuSnOPF),zinc biscaproate (ZnCap), and zinc bis(pentafluoro-phenyl sulfide) (ZnSPF). The temperature was varied between 110 and 180°C and the time between 3 h and 7 days. For the few polyglycolides (PGAs) that were soluble extremely high molecular masses were obtained. The MALDI TOF mass spectra had all a low signal-to-noise ration and displayed the peaks of cyclic PGAs with a“saw-tooth pattern ”indicating formation of extended-ring crystallites in the mass range below m/z 2500. The shape of DSC curves varied considerably with catalyst and reaction conditions, whereas the long-distance values measured by SAXS were small and varied little with the polymeriza-tion conditions.
KW - MALDI TOF MS
KW - Polyglycolide
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598221
DO - https://doi.org/10.1002/pat.6365
VL - 35
IS - 4
SP - 1
EP - 10
PB - John Wiley & Sons Ltd.
AN - OPUS4-59822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
T1 - Low Molar Mass Cyclic Poly(L-lactide)s: Separate Transesterification Reactions of Cycles and Linear Chains in the Solid State
N2 - L-Lactide (LA) was polymerized with neat tin(II) 2-ethylhexanoate (SnOct2) in toluene at 115 °C at low concentration with variation of the LA/Cat ratio. Cyclic polylactides (cPLAs) with number average molecular weights (Mn) between 7 000 and 17 000 were obtained. MALDI-TOF mass spectrometry also revealed the formation of a few percent of linear chains. Crystalline cPLAs with Mn around 9 000 and 14 000 were annealed at 140 °C in the presence of ScOct2 or dibutyl-2-stanna-1,3-dithiolane (DSTL). Simultaneously, crystallites of extended linear chains and crystallites of extended cycles were formed regardless of the catalyst, indicating that transesterification reaction proceeded different for linear chains and for cycles, governed by thermodynamic control. The formation of extended chain crystallites with low dispersity indicates the existence of symproportionation of short and long chains. A complementary experiment was carried out with a PLA ethyl ester composed mainly of linear chains with a small fraction of cycles
KW - Polylactide
KW - MALDI-TOF MS
KW - Annealing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-606228
DO - https://doi.org/10.1039/D4SM00567H
SN - 1744-6848
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60622
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dalgic, Mete-Sungur
A1 - Weidner, Steffen
T1 - Solvent-free sample preparation for matrix-assisted laserdesorption/ionization time-of-flight mass spectrometry ofpolymer blends
N2 - Solvent-free sample preparation offers some advantages over solvent-based techniques, such as improved accuracy, reproducibility and sensitivity, for matrix-assisted laser desorption/ionization (MALDI) analysis. However, little or no information is available on the application of solvent-free techniques for the MALDI analysis of polymer blends. Solvent-free sample preparation by ball milling was applied with varying sample-to-matrix ratios for MALDI time-of-flight mass spectrometry analysis of various polymers, including polystyrenes, poly(methyl methacrylate)s and poly(ethylene glycol)s. The peak intensity ratios were compared with those obtained after using the conventional dried droplet sample preparation method. In addition, solvent-assisted milling was also applied to improve sample homogeneities.
Depending on the sample preparation method used, different peak intensity ratios were found, showing varying degrees of suppression of the signal intensities of higher mass polymers. Ball milling for up to 30 min was required to achieve constant intensity ratios indicating homogeneous mixtures. The use of wet-assisted grinding to improve the homogeneity of the blends was found to be disadvantageous as it caused partial degradation and mass-dependent segregation of the polymers in the vials.The results clearly show that solvent-free sample preparation must be carefully considered when applied to synthetic polymer blends, as it may cause additional problems with regard to homogeneity and stability of the blends.
KW - MALDI TOF MS
KW - Sample preparation
KW - Polymer blends
KW - Solvent-free
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598570
DO - https://doi.org/10.1002/rcm.9756
SN - 0951-4198
VL - 38
IS - 12
SP - 1
EP - 9
PB - Wiley online library
AN - OPUS4-59857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H.
T1 - Transformation of poly(L-lactide) crystals composed of linear chains into crystals composed of cycles
N2 - A poly(L-lactide) with a trifluoroethyl ester end group and an average degree of polymerization (DP) of 50 was synthesized by ROP of L-lactide initiated with trifluoroethanol. Small-angle X-ray scattering (SAXS) in combination with differential scanning calorimetry (DSC) measurements revealed an average crystal thickness of 13 nm, corresponding to 45 repeat units. This suggests that most crystallites were formed by extended PLA chains, and both flat surfaces were covered by CF3 groups. The crystalline PLAs were annealed at 140 or 160 °C in the presence of two catalysts: tin(II) 2-ethylhexanoate, (SnOct2) or dibutyltin bis(pentafluorophenoxide) (BuSnPhF). The chemical reactions, such as polycondensation and cyclization, proceeded in the solid state and were monitored by matrix-assisted laser desorption/ionization time-offlight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC) measurements. Under optimal conditions a large fraction of linear chains was transformed into crystallites composed of extended cycles. Additionally, MALDI TOF MS analysis of GPC fractions from samples annealed for 28 or 42 days detected chain elongation of the linear species up to a factor of 20.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
KW - Transesterification
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597250
DO - https://doi.org/10.1039/D3PY01370G
SN - 1759-9954
VL - 15
IS - 12
SP - 1173
EP - 1181
PB - Royal Society for Chemistry
AN - OPUS4-59725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Kricheldorf, H. R.
T1 - Matrix-assisted laser desorption/ionization behavior of neat linear and cyclic poly(L-lactide)s and their blends
N2 - Numerous new tin catalysts that enable the synthesis of cyclic polylactides with broad variation in their molecular mass were recently developed. The abundance of cyclics in matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectra is, however, frequently reported to greatly exceed that of linears. Thus, the MALDI ionization behavior of various end-capped linear poly(L-lactide)s and one cyclic poly(L-lactide) was investigated and compared.
Neat compounds and various blends of cyclic and linear species were prepared and studied under identical conditions with regard to sample preparation and instrumental condition, except for the laser power. For this purpose, two different MALDI-TOF mass spectrometers were applied.
Our results reveal that cyclics indeed show a slightly better ionization in MALDI, although their ionization as a neat compound seems to be less effective than that of linear polylactides. The ionization of most linear polylactides investigated does not depend on the end group structure. However, linear polylactides containing 12-bromododecyl end groups reveal an unexpected saturation effect that is not caused by fragmentation of the polymer or the end group, or by electronic saturation of the detector digitizer. Furthermore, polylactides with a 2-bromoethyl end group did not show such a saturation effect.
An overestimation of cyclic species in MALDI-TOF mass spectra of poly(L-lactide)s must be considered, but the commonly assumed peak suppression of linear polymers in mixtures of both structures can be excluded.
KW - Polylactide
KW - MALDI-TOF MS
KW - Blends
KW - Ionization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504216
DO - https://doi.org/10.1002/rcm.8673
VL - 34
SP - e8673
PB - Wiley Online Libary
AN - OPUS4-50421
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - SnOct2-catalyzed and alcohol-initiated ROPS of L-lactide - Control of the molecular weight and the role of cyclization
N2 - Ring-opening polymerizations (ROP) of l-lactide (LA) are conducted in bulk at 130, 160, or 180 °C and are initiated with two different alcohols at 160 °C. The lactide/initiator ratio (LA/In) is varied from 50/1 (20/1 at 180 °C) to 900/1 and the lactide/catalyst ratio (LA/Cat) between 2000/1 and 8000/1. At all temperatures a nearly perfect control of number average molecular weight (Mn) via the LA/In ratio is feasible up to LA/In = 200/1, but at higher ratios the Mn value lags behind the theoretical values and the discrepancy increases with higher LA/Cat ratios. Variation of the LA/Cat ratio influences the formation of cycles but does not significantly influence Mn, when the LA/In ratio is kept constant. The formation of cycles is favored by lower In/Cat ratios and is the main reason for the unsatisfactory control of Mn at high LA/In ratios. The results also suggest that the cycles are mainly or exclusively formed by end-to-end cyclization and not, as believed previously, by back-biting.
KW - Polylactide
KW - MALDI-TOF MS
KW - Cyclization
KW - Ring-opening polymerization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543066
DO - https://doi.org/10.1002/macp.202100464
SN - 1521-3935
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Syntheses of Polyglycolide via Polycondensation: A Reinvestigation
N2 - The Na salt of chloroacetic acid is condensed in suspension. Furthermore,glycolic acid is condensed in bulk or in concentrated solution by means of SnCl2 or 4-toluene sulfonic acid (TSA) as catalysts. The temperatures are varied from 160 to 200°C and the time from 1 to 5 days. Low molar mass cyclic poly(glycolic acid) (PGA) is detected by means of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry in most PGAs. A predominance of certain cycles having an even number of repeat units is observed suggesting a thermodynamically favored formation of extended-ring crystals. Extremely high melting temperatures (up to 237.5°C)and high melting enthalpies are found for polycondensations with TSA in 1,2-dichlorobenzene.
KW - MALDI TOF MS
KW - Polycondensation
KW - Polyglycolide
KW - Cyclization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596856
DO - https://doi.org/10.1002/macp.202300397
IS - 2300397
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-59685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steinkönig, J.
A1 - Bloesser, F. R.
A1 - Huber, B.
A1 - Welle, A.
A1 - Trouillet, V.
A1 - Weidner, Steffen
A1 - Barner, L.
A1 - Roesky, P. W.
A1 - Yuan, J.
A1 - Goldmann, A. S.
A1 - Barner-Kowollik, C.
T1 - Controlled radical polymerization and in-depth mass-spectrometric characterization of poly(ionic liquid)s and their photopatterning on surfaces
N2 - The preparation and characterization of poly(ionic liquid)s (PILs) bearing a polystyrene backbone via reversible addition fragmentation chain transfer (RAFT) polymerization and their photolithographic patterning on silicon wafers is reported. The controlled radical polymerization of the styrenic ionic liquid (IL) monomers ([BVBIM]X, X = Cl− or Tf2N−) by RAFT polymerization is investigated in detail. We provide a general synthetic tool to access this class of PILs with controlled molecular weight and relatively narrow molecular weight distribution (2000 g mol−1 ≤ Mn ≤ 10 000 g mol−1 with dispersities between 1.4 and 1.3 for p([BVBIM]Cl); 2100 g mol−1 ≤ MP ≤ 14 000 g mol−1 for p([BVBIM]Tf2N)). More importantly, we provide an in-depth characterization of the PILs and demonstrate a detailed mass spectrometric analysis via matrix-assisted laser desorption ionization (MALDI) as well as – for the first time for PILs – electrospray ionization mass spectrometry (ESI-MS). Importantly, p([BVBIM]Cl) and p([DMVBIM]Tf2N) were photochemically patterned on silicon wafers. Therefore, a RAFT agent carrying a photoactive group based on ortho-quinodimethane chemistry – more precisely photoenol chemistry – was photochemically linked for subsequent controlled radical polymerization of [BVBIM]Cl and [DMVBIM]Tf2N. The successful spatially-resolved photografting is evidenced by surface-sensitive characterization methods such as X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The presented method allows for the functionalization of diverse surfaces with poly(ionic liquid)s.
KW - reversible addition fragmentation chain transfer (RAFT) polymerization
KW - polyionic liquids
KW - mass spectrometry
KW - surface modification
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355202
DO - https://doi.org/10.1039/C5PY01320H
VL - 7
SP - 451
EP - 461
PB - Royal Society of Chemistry
CY - Cambridge
AN - OPUS4-35520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zydziak, N.
A1 - Konrad, W.
A1 - Feist, F.
A1 - Afonin, S.
A1 - Weidner, Steffen
A1 - Barner-Kowollik, C.
T1 - Coding and decoding libraries of sequence-defined functional copolymers synthesized via photoligation
N2 - Designing artificial macromolecules with absolute sequence order represents a considerable challenge. Here we report an advanced light-induced avenue to monodisperse sequencedefined functional linear macromolecules up to decamers via a unique photochemical approach. The versatility of the synthetic strategy—combining sequential and modular concepts—enables the synthesis of perfect macromolecules varying in chemical constitution and topology. Specific functions are placed at arbitrary positions along the chain via the successive addition of monomer units and blocks, leading to a library of functional homopolymers, alternating copolymers and block copolymers. The in-depth characterization of each sequence-defined chain confirms the precision nature of the macromolecules. Decoding of the functional information contained in the molecular structure is achieved via tandem mass spectrometry without recourse to their synthetic history, showing that the sequence information can be read.We submit that the presented photochemical strategy is a viable and advanced concept for coding individual monomer units along a macromolecular chain.
KW - Photoligation
KW - Copolymer sequence
KW - MALDI-TOF MS/MS
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391542
DO - https://doi.org/10.1038/ncomms13672
SN - 2041-1723
VL - 7
SP - Artikel Nr. 13672
AN - OPUS4-39154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diehn, Sabrina
A1 - Zimmermann, B.
A1 - Bagcioglu, M.
A1 - Seifert, Stephan
A1 - Kohler, A.
A1 - Ohlson, M.
A1 - Fjellheim, S.
A1 - Weidner, Steffen
A1 - Kneipp, Janina
T1 - Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) shows adaption of grass pollen composition
N2 - MALDI time-of-flight mass spectrometry (MALDI-TOF MS) has become a widely used tool for the classification of biological samples. The complex chemical composition of pollen grains leads to highly specific, fingerprint-like mass spectra, with respect to the pollen species. Beyond the species-specific composition, the variances in pollen chemistry can be hierarchically structured, including the level of different populations, of environmental conditions or different genotypes. We demonstrate here the sensitivity of MALDI-TOF MS regarding the adaption of the chemical composition of three Poaceae (grass) pollen for different populations of parent plants by analyzing the mass spectra with partial least squares discriminant analysis (PLS-DA) and principal component analysis (PCA). Thereby, variances in species, population and specific growth conditions of the plants were observed simultaneously. In particular, the chemical pattern revealed by the MALDI spectra enabled discrimination of the different populations of one species. Specifically, the role of environmental changes and their effect on the pollen chemistry of three different grass species is discussed. Analysis of the Group formation within the respective populations showed a varying influence of plant genotype on the classification, depending on the species, and permits conclusions regarding the respective rigidity or plasticity towards environmental changes.
KW - Pollen
KW - MALDI-TOF MS
KW - Classification
KW - Partial least square discriminant analysis (PLS-DA)
KW - Principal component analysis (PCA)
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465294
DO - https://doi.org/10.1038/s41598-018-34800-1
SN - 2045-2322
VL - 8
IS - 1
SP - 16591, 1
EP - 11
PB - Nature
AN - OPUS4-46529
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, A.
A1 - Weidner, Steffen
A1 - Kricheldorf, H.
T1 - Stereocomplexation of cyclic polylactides with each other and with linear poly(L-lactide)s
N2 - Two kinds of cyclic poly(D- and L-lactide)s were synthesized, namely CI labeled samples mainly consisting of even-numbered cycles with low dispersity and CII, CIII or CIV-labeled ones consisting of equal amounts of even and odd-numbered cycles with high dispersity and igher molecular weights (Mw up to 300 000). Furthermore, linear poly L-lactide)s were prepared by initiation with ethanol and in both series the molecular weight was varied. The formation of stereocomplexes from cyclic poly(D-lactide)s and all kinds of poly L-lactide)s was performed in dichloromethane/toluene mixtures. The stereocomplexes crystallized from the reaction mixture were characterized in the virgin state and after annealing at 205 °C.
Stereocomplexes free of stereohomopolymers with crystallinities up to 80% were obtained from all experiments in yields ranging from 60 to 80%. Despite the high annealing temperature (maintained for 1 h), little transesterification was observed and the crystallinity slightly increased.
KW - Polylactide
KW - MALDI-TOF MS
KW - Stereocomplex
KW - Cyclic
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496693
DO - https://doi.org/10.1039/c9py01236b
VL - 10
SP - 6191
EP - 6199
PB - Royal Society for Chemistry
AN - OPUS4-49669
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Synthesis of cyclic polymers and flaws of the Jacobson–Stockmayer theory
N2 - Cyclic poly(L-lactide)s were prepared by ring-opening polymerization combined with simultaneous polycondensation (ROPPOC) in bulk at 160 ° with dibutyltin bis(4-cyanophenoxide) as catalyst. It is demonstrated by MALDI TOF mass spectrometry and 1H NMR end group analyses that cycles are formed by endto-end cyclization in addition to “back-biting” transesterification. Formation of high molar mass cyclic poly L-lactide)s by means of several more reactive ROPPOC catalysts presented previously and in new experiments is discussed. These experimental results, together with theoretical arguments, prove that part of the Jacobson–Stockmayer theory is wrong. The critical monomer concentration, above which end-toend cyclization is seemingly impossible, does not exist and reversible like irreversible polycondensations can theoretically proceed up to 100% conversion, so that finally all reaction products will necessarily adopt a cyclic architecture.
KW - Polylactide
KW - MALDI-TOF MS
KW - Cyclization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506419
DO - https://doi.org/10.1039/d0py00226g
VL - 11
IS - 14
SP - 2595
EP - 2604
PB - Royal Society for Chemistry
AN - OPUS4-50641
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lauer, Franziska
A1 - Seifert, Stephan
A1 - Kneipp, Janina
A1 - Weidner, Steffen
T1 - Simplifying the Preparation of Pollen Grains for MALDI-TOF MS Classification
N2 - Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is a well-implemented analytical technique for the investigation of complex biological samples. In MS, the sample preparation strategy is decisive for the success of the measurements. Here, sample preparation processes and target materials for the investigation of different pollen grains are compared. A reduced and optimized sample preparation process prior to MALDI-TOF measurement is presented using conductive carbon tape as target. The application of conductive tape yields in enhanced absolute signal intensities and mass spectral pattern information, which leads to a clear separation in subsequent pattern analysis. The results will be used to improve the taxonomic differentiation and identification, and might be useful for the development of a simple routine method to identify pollen based on mass spectrometry.
KW - PCA
KW - MALDI-TOF MS
KW - Conductive carbon tape
KW - Pollen
KW - Sample pretreatment
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-392885
UR - http://www.mdpi.com/1422-0067/18/3/543/
DO - https://doi.org/10.3390/ijms18030543
SN - 1422-0067
VL - 18
IS - 3
SP - 543
EP - 554
PB - MDPI AG
CY - Basel, Switzerland
AN - OPUS4-39288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Synthesis of cyclic poly(l-lactide) catalyzed by Bismuth salicylates-A combination of two drugs
N2 - l‐lactide was polymerized in bulk at 160 or 180°C with mixtures of bismuth subsalicylate (BiSub) and salicylic (SA) as catalysts. The SA/Bi ratio and the monomer/Bi ratio were varied. The highest molecular weights (weight average, Mw) were achieved at a SA/Bi ratio of 1/1 (Mw up to 92 000 g mol−1). l‐Lactide was also polymerized with combinations of BiSub and silylated SA, and Mw values up to 120 000 g mol−1 were achieved at 180°C. MALDI‐TOF mass spectrometry and Mark‐Houwink‐Sakurada measurements proved that under optimized reaction conditions the resulting polylactides consist of cycles.
KW - Polylactide
KW - MALDI-TOF MS
KW - Cyclization
KW - Catalyst
KW - Salicylate
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-488622
DO - https://doi.org/10.1002/pola.29473
SN - 0887-624X
SN - 1099-0518
SP - 29473
PB - Wiley
AN - OPUS4-48862
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H. R.
T1 - Ring–Ring Equilibration in Solid, Even-Numbered Cyclic Poly(l-lactide)s and their Stereocomplexes
N2 - Even-numbered cyclic poly(d-lactide) and poly(l-lactide) are prepared by ringexpansion polymerization. The cyclic pol(l-lactide) is annealed either at 120 or at 160 °C for several days. The progress of transesterification in the solid state is monitored by the formation of odd-numbered cycles via matrix-assisted laser desorption/ionization-time of flight mass spectrometry. The changes of the crystallinity are monitored by differential scanning calorimetry, wideand small-angle x-ray scattering (WAXS and SAXS) measurements. Despite total even-odd equilibration at 160 °C, the crystallinity of poly(l-lactide) is not reduced. Furthermore, the crystallinity of the stereocomplexes of both cyclic polylactides do not decrease or vanish, as expected, when a blocky or random stereosequence is formed by transesterification. This conclusion is confirmed by 13C NMR spectroscopy. These measurements demonstrate that transesterification is a ring–ring equilibration involving the loops on the surfaces of the lamellar crystallites thereby improving crystallinity and 3D packing of crystallites without significant broadening of the molecular weight distribution.
KW - Polylactide
KW - MALDI-TOF MS
KW - Cyclization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506458
DO - https://doi.org/10.1002/macp.202000012
VL - 221
IS - 9
SP - 2000012
PB - Wiley-VCH Verlag
AN - OPUS4-50645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Doriti, A.
A1 - Brosnan, S.
A1 - Weidner, Steffen
A1 - Schlaad, H.
T1 - Synthesis of polysarcosine from air and moisture stable N-phenoxycarbonyl-N-methylglycine assisted by tertiary amine base
N2 - Polysarcosine (M-n = 3650-20 000 g mol(-1), D similar to 1.1) was synthesized from the air and moisture stable N-phenoxycarbonyl-N-methylglycine. Polymerization was achieved by in situ transformation of the urethane precursor into the corresponding N-methylglycine-N-carboxyanhydride, when in the presence of a non-nucleophilic tertiary amine base and a primary amine initiator.
KW - Polysarcosine
KW - MALDI-TOF MS
KW - Synthesis
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-359309
DO - https://doi.org/10.1039/c6py00221h
SN - 1759-9954
SN - 1759-9962
VL - 7
IS - 18
SP - 3067
EP - 3070
AN - OPUS4-35930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
T1 - Synthesis of polylactides by means of tin catalysts
N2 - This article reviews the usefulness of tin(II) and tin(IV) salts and compounds as catalysts for the polymerization of lactides. The text is subdivided into nine parts mainly reflecting different polymerization strategies, such as ring-opening polymerization (ROP), ring-expansion polymerization (REP), ROP combined with simultaneous polycondensation (ROPPOC), various catalysts with unknown polymerization mechanisms, and polycondensation of lactic acid. Since the toxicity of tin salts and compounds is a matter of concern and frequently mentioned in numerous publications, the first section deals with facts instead of myths about the toxicity of tin salts and compounds.
KW - Polylactide
KW - MALDI-TOF MS
KW - Tin catalysts
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545050
DO - https://doi.org/10.1039/d2py00092j
SP - 1
EP - 30
PB - Royal Society for Chemistry
AN - OPUS4-54505
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
T1 - Ring-ring equilibration (RRE) of cyclic poly(L-lactide)s by means of cyclic tin catalysts
N2 - With 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzoxepane (SnBiPh) as catalysts ring-expansion polymerizations (REP) were performed either in 2 M solution using three different solvents and two different temperatures or in bulk at 140 and 120 ◦C. A kinetically controlled rapid REP up to weight average molecular masses (Mẃs) above 300 000 was followed by a slower degradation of the molecular masses at 140 ◦C, but not at 120 ◦C Furthermore, a low molecular mass cyclic poly(L-lactide) (cPLA) with a Mn around 16 000 was prepared by polymerization in dilute solution and used as starting material for ring-ring equilibration at 140 ◦C in 2 M solutions. Again, a decrease of the molecular mass was detectable, suggesting that the equilibrium Mn is below 5 000. The degradation of the molecular masses via RRE was surprisingly more effective in solid cyclic PLA than in solution, and a specific transesterification mechanism involving loops on the surface of crystallites is proposed. This degradation favored the formation of extended-ring crystallites, which were detectable by a “saw-tooth pattern” in their MALDI mass spectra.
KW - Organic Chemistry
KW - Polymers and Plastics
KW - MALDI-TOF MS
KW - Materials Chemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593819
DO - https://doi.org/10.1016/j.eurpolymj.2024.112765
SN - 0014-3057
VL - 206
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-59381
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Falkenhagen, Jana
A1 - Kricheldorf, H. R.
T1 - Polycondensations and Cyclization of Poly(L-lactide) Ethyl Esters in the Solid State
N2 - The usefulness of seven different Tin catalysts, Bismuth subsalicylate and Titan tetra(ethoxide) for the polycondensation of ethyl L-lactate (ELA) was examined at 150 °C/6 d. Dibutyltin bis(phenoxides) proved to be particularly effective. Despite the low reactivity of ELA, weight average molecular masses (Mw) up to 12 500 were found along with partial crystallization. Furthermore, polylactides (PLAs) of similar molecular masses were prepared via ELA-initiated ROPs of L-lactide by means of the four most effective polycondensation catalysts. The crystalline linear PLAs were annealed at 140 or 160 °C in the presence of these catalysts. The consequences of the transesterification reactions in the solid PLAs were studied by means of matrix-assisted laser desorption/ionization (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC) and small-angle X-ray scattering (SAXS). The results indicate that polycondensation and formation of cycles proceed in the solid state via formation of loops on the surface of the crystallites. In summary, five different transesterification reactions are required to explain all results.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592934
DO - https://doi.org/10.1039/d3py01232h
SN - 1759-9962
VL - 15
IS - 2
SP - 71
EP - 82
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-59293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Scheliga, F.
A1 - Weidner, Steffen
T1 - Syntheses of Cyclic Poly(l-lactide)s by Means of Zinc-Based Ring-Opening Polymerization with Simultaneous Polycondensation (ROPPOC) Catalysts
N2 - Ring-opening polymerizations of l-lactide are studied in bulk at 140 or 160 °C with zinc n-hexanoate, zinc 4-chlorothiophenolate, and zinc pentafluoro thiophenolate (ZnSPF) as catalysts. The reactivity increases in the given order.
With all three catalysts a high fraction of cycles is obtained only at polymerization (annealing) times around 7 d. With ZnSPF weight average molecular weights (Mw) up to 178 000, a Tm around 199 °C and a 𝚫Hm around 99 J g−1 were achieved. The samples annealed for 4 or 7 d also display a saw tooth pattern of the mass peak distribution in the matrix-assisted laser desorption/ionization time of flight spectra indicating transesterification reactions across the surface of extended ring crystals. This process optimizes the thermodynamical properties of the crystalline cyclic polylactides and is responsible for the high Tm and 𝚫Hm values.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring opening polymerization
KW - Polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578264
DO - https://doi.org/10.1002/macp.202300070
SN - 1022-1352
SP - 202300070
PB - Wiley VHC-Verlag
AN - OPUS4-57826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Ring-opening polymerizations of L-Lactide catalyzed by zinc caprylate: Syntheses of cyclic and linear poly(L-lactide)s
N2 - Alcohol-initiated ring-opening polymerizations (ROPs) of L-Lactide (LA) were conducted in bulk at 130 °C catalyzed by Zn acetate (ZnAc2), lactate (ZnLac2), or caprylate (ZnCap2). 11-undecenol (UND), 1-hydroxymethylnaphtalene (HMN), and 4-nitrobenzylalcohol (4NB) were used as alcohols. Whereas variation of the alcohols had little effect, the usefulness of the catalysts increased in the order: acetate < lactate < caprylate. Hence, further alcohol-initiated polymerizations were performed with ZnCap2 alone and with variation of the lactide/catalyst (LA/Cat) ratio. With increasing LA/Cat ratio higher fractions of cyclic poly(L-lactide) (PLA) were found, so that the measured degree of polymerization (DP) is considerably lower than the theoretical value (i.e., 2 x LA/alcohol). With neat ZnCap2 cyclic PLAs were the largely prevailing reaction products. For these cyclic PLAs weight average molar masses (Mw) up to 134,000 were obtained and an optical purity around 99% was indicated by 13C NMR spectroscopy and DSC measurements even after 48 h at 150 or 160 °C.
KW - Cyclization
KW - Lactide
KW - Ring opening polymerization
KW - Transesterification
KW - Zinc catalyst
KW - MALDI
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557565
DO - https://doi.org/10.1002/pol.20220328
SN - 2642-4150
SP - 1
EP - 10
PB - Wiley
AN - OPUS4-55756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
T1 - Cyclic and linear poly(L-lactide)s by ring-expansion polymerization with Bu2SnO, Oct2SnO, and Bu2SnS
N2 - To elucidate the usefulness of commercial Bu2SnO as catalyst for syntheses of linear and/or cyclic polylactides L-Lactide was polymerized in bulk with variation of the LA/Cat ratio, temperature and time. Based on a ring-expansion polymerization (REP) mechanism cyclic polylactides (PLAs) with weight average molecular weights in the range of 200,000–300,000 are obtained at the highest temperature (180 °C). Polymerizations at 150 °C yielded crystalline, mainly cyclic polylactides which, after annealing, showed high melting temperatures (up to 197.5 °C) and high crystallinities (>80%). Polymerization at 120 °C confirmed the trend towards more linear chains with lower temperatures but yielded extended-ring crystals showing a “saw-tooth pattern” in the mass spectra. Oct2SnO gave similar results as Bu2SnO. Bu2SnS proved a sluggish polymerization catalyst, but a good transesterification catalyst in solid PLA.
KW - MALDI TOF MS
KW - Biobased polymers
KW - Polylactide
KW - Ring-expansion polymerization
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584121
DO - https://doi.org/10.1002/pol.20230515
SN - 2642-4169
SP - 1
EP - 10
PB - Wiley
CY - Hoboken, NJ
AN - OPUS4-58412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H. R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About the Influence of (Non-)Solvents on the Ring Expansion Polymerization of l-Lactide and the Formation of Extended Ring Crystals
N2 - Ring-expansion polymerizations (REPs) catalyzed by two cyclic tin catalysts (2-stanna-1.3-dioxa-4,5,6,7-dibenzazepine [SnBiph] and
2,2-dibutyl-2-stanna-1,3-dithiolane [DSTL]) are performed at 140 °C in bulk.
Small amounts (4 vol%) of chlorobenzene or other solvents are added to
facilitate transesterification reactions (ring–ring equilibration) in the solid poly(l-lactide)s. In the mass range up to m/z 13 000 crystalline PLAs displaying a so-called saw-tooth pattern in the MALDI-TOF mass spectra are obtained indicating the formation of extended-ring crystals. The characteristics of extended-ring crystallites and folded-ring crystallites are discussed. Furthermore, extremely high melting temperatures (Tm’s up to 201.2 °C) and melting enthalpies (𝚫Hm’s up to 106 J g−1)) are found confirming that 𝚫Hm max, the 𝚫Hm of a perfect crystal, is around or above 115 J g−1 in contrast to literature data.
KW - Polylactide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Biobased
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-573063
DO - https://doi.org/10.1002/macp.202200385
VL - 224
IS - 5
SP - 1
EP - 8
PB - Wiley VHC-Verlag
AN - OPUS4-57306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geburtig, Anja
A1 - Wachtendorf, Volker
A1 - Falkenhagen, Jana
T1 - Combined impact of UV radiation and nitric acid on high‐density polyethylene containers as a laboratory test
N2 - In a laboratory test, transparent high‐density polyethylene (HDPE) jerrycans have been exposed to both UV radiation and 55 wt‐% nitric acid solution at (41 ± 2)°C, for up to 20 days. For comparison, UV radiant exposure (21 days) and nitric acid exposure (up to 6 weeks) were performed separately, at nearly equal temperatures. The damages are compared with FTIR spectroscopy in ATR and HT‐gel permeation chromatography(GPC) on a molecular level and with hydraulic internal pressure testing as a component test. For the used jerrycans, relevant oxidation can only be found after the combined exposure. This is caused by the decomposition of nitric acid into nitrous gases by UV radiation, which is also observed at lower concentrations (28 wt‐%). After 6 days of laboratory exposure, this is rated as critical, which corresponds to about 1/10 year in Central Europe, according to the UV radiant exposure. The gradual increase in oxidative damage shows the reproducibility of the test.
KW - Molecular mass distribution
KW - High-density polyethylene
KW - Nitric acid
KW - UV radiation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550141
DO - https://doi.org/10.1002/pts.2673
SN - 0894-3214
VL - 35
IS - 10
SP - 729
EP - 735
PB - Wiley
CY - New York, NY
AN - OPUS4-55014
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans. R.
A1 - Weidner, Steffen
T1 - About the Toxicity of Polymerization Catalysts and Polymer Additives Based on Tin(II) Salts and Tin(IV) Compounds
N2 - This article reviews and discusses information on the toxicity of numerous tin-based catalysts used in academic research and industrial production for the synthesis of various polymers, such as polyesters, polyurethanes, and polysiloxanes. Tin(IV) compounds used as additives and as PVC stabilizers are also considered. Emphasis is put on the differentiation between tin(II) salts on the one hand and tin(IV) compounds on the other hand. In the first chapter, historical facts about human contact with stannous ions are discussed, along with toxicity studies of canned foods and beverages. In the second part, toxicity tests based on cell cultures and medical applications of tin(II)-containing films or implants are described. The third part focuses on alkyl and aryl tin(IV) compounds.
KW - Tin
KW - Toxicity
KW - Environment
KW - Polymer catalysts
KW - Polymer additives
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642877
DO - https://doi.org/10.1021/acs.chas.5c00105
SN - 1871-5532
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-64287
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meyer, Andreas
A1 - Weidner, Steffen
A1 - Kricheldorf, Hans R.
T1 - Star-shaped poly(l-lactide)s based on pentaerythritol: About crystallization and polycondensation plus disproportionation and ring formation in the solid state
N2 - Star-shaped poly( L-lactide)s (s-PLAs), were prepared by ring-opening polymerization of with pentaerythritol and catalyzed by tin(II) 2-ethylhyexanoate (SnOct out in bulk at either 120 ◦ C or 160 ◦ L-lactide (LA) initiated 2 ). Two small series of ROPs were carried C with variation of the LA/initiator ratio. Matrix-assisted laser desorption/ ionization time-of-flight (MALDI-TOF) mass spectra revealed traces of cycles in 120 ◦ C samples only at low initiator/catalyst ratios. In contrast, higher fractions of cycles were detected in samples prepared at 160 C, suggesting a "back-biting" origin. The influence of arm length and thermal history on crystallinity was investigated by differential scanning calorimetry (DSC) and wide-angle x-ray scattering (WAXS). It was shown that annealing increased the melting temperature (T ◦ ◦ m ) and crystallinity. However, annealing at 140 ◦ C for 14 d also caused significant solid-state transesterification. In addition, crystallites composed of s-PLAs with extended arms and, simultaneously, crystallites composed exclusively of extended rings were formed, identified by their typical "sawtooth" pattern in the MALDI mass spectra. Small angle x-ray scattering (SAXS) indicated that the crystal thickness was lower than that of linear PLAs annealed under identical conditions, but increased upon annealing at 140 C.
KW - MALDI-TOF MS
KW - Polylactide
KW - Crystallisation
KW - AStar-shaped polymers
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636832
DO - https://doi.org/10.1016/j.polymer.2025.128709
SN - 0032-3861
VL - 334
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rösler, Alexander
A1 - Weidner, Steffen
A1 - Klamroth, Tillmann
A1 - Müller, Axel H. E.
A1 - Schlaad, Helmut
T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents
N2 - The kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations.
KW - MALDI-TOF MS
KW - Anionic polymerization
KW - β‐myrcene
KW - Kinetics
KW - Reaction order
KW - Activation energy
KW - Microstructure
KW - Quantum chemical calculations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630900
DO - https://doi.org/10.1002/pi.6772
SN - 1097-0126
SP - 1
EP - 8
PB - Wiley
CY - New York, NY
AN - OPUS4-63090
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
T1 - Polymerization of L‐Lactide Catalyzed by Metal Acetylacetonate Complexes
N2 - ABSTRACTRing‐opening polymerizations (ROPs) of l‐lactide (LA) were performed at 120°C, 140°C, 150°C, and 180°C in bulk catalyzed by acetylacetonate (acac) complexes of manganese(II), nickel(II), copper(II), zirconium(IV), dibutyltin(IV), and vanadyl(V). These experiments revealed that only the acac complexes of Zr and Bu2Sn were reactive enough to enable quantitative polymerization within a few hours. Further ROPs with Bu2Sn(acac)2 and Zr(acac)4 showed that Bu2Sn(acac)2 had a slightly lower reactivity than the Zr complex. The ROPs catalyzed with Zr(acac)4 yielded number average molecular weights (Mn) up to 70,000 g mol−1. The matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectra indicated an exclusive formation of cycles in the mass range of up to m/z 13,000 for Zr(acac)4 and up to m/z 18,000 for Bu2Sn(acac)2. Unusually high melting temperatures (187°C–192°C) were also achieved along with high crystallinities. Furthermore, four lactide/glycolide copolymerizations catalyzed by Zr(acac)4 were performed, and the topology and the extent of transesterification were characterized by MALDI‐TOF mass spectrometry and 13C NMR spectroscopy.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Acetylacetonate
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639754
DO - https://doi.org/10.1002/pol.20250788
SN - 2642-4150
SP - 1
EP - 9
PB - Wiley Periodicals LLC.
AN - OPUS4-63975
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
T1 - Zwitterionic polymerization of glycolide catalyzed by pyridine
N2 - The usefulness of various N- and P-based catalysts for syntheses of cyclic polyglycolide via zwitterionic polymerization of glycolide was examined. Most catalysts produced discolored, largely insoluble polyglycolides consisting of cycles and unidentified byproducts. Soluble, cyclic polyglycolides were obtained using neat pyridine as catalyst at 120 °C, 100 °C, 80 °C, and even at 60 °C. The number-average molecular weights were extremely low and depended slightly on the glycolide-to-pyridine ratio. Three different mass distributions of the cycles were detected by mass spectrometry, depending on the reaction conditions. The cyclic polyglycolides were also characterized by differential scanning calorimetry (DSC) and small-angle X-ray scattering (SAXS) measurements. The SAXS data in combination with the mass spectra indicate that the majority of the cycles form extended-ring crystallites
KW - MALDI-TOF MS
KW - Polylactide
KW - Polymerization
KW - Zitterions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639748
DO - https://doi.org/10.1039/d5py00762c
SN - 1759-9954
SP - 1
EP - 9
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63974
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rösler, Alexander
A1 - Weidner, Steffen
A1 - Klamroth, Tillmann
A1 - Müller, Axel HE
A1 - Schlaad, Helmut
T1 - Kinetics of anionic polymerization of β‐myrcene in hydrocarbon solvents
N2 - AbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
KW - Myrcene
KW - Anionic polymerization
KW - Reaction order
KW - Activation energy
KW - Microstructure
KW - Quantum chemical calculation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636840
DO - https://doi.org/10.1002/pi.6772
SN - 0959-8103
SP - 1
EP - 8
PB - Wiley
AN - OPUS4-63684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fink, Friedrich
A1 - Stawski, Tomasz M.
A1 - Emmerling, Franziska
A1 - Falkenhagen, Jana
T1 - A novel machine-learning approach to unlock technical lignin classification by NIR spectroscopy - bench to handheld
N2 - In this research, the utilization of near-infrared (NIR) spectroscopy in conjunction with advanced machine learning methods is investigated for categorizing technical lignins obtained from different biomass sources and industrial procedures. Technical lignins, such as kraft, organosolv and lignosulfonates, have different chemical compositions, which continue to make uniform characterization and application in sustainable sectors extremely difficult. Fast, universally accessible analytics combined with data analysis is still an open question. For the first time three distinct NIR spectrometers—a high-performance benchtop system, a mid-priced compact device, and an economical handheld unit—were utilized to record NIR spectra of 31 unique lignin samples. The spectra underwent pre-processing through standard normal variate (SNV) transformation and Savitzky-Golay derivatives to amplify spectral features and decrease noise. Principal component analysis (PCA) was employed to reduce data complexity and extract crucial characteristics for classification purposes. Subsequently, four machine learning algorithms—Support Vector Machines (SVM), Gaussian Naive Bayes (GNB), Gaussian Process Classification (GPC), and Decision Tree Classification (DTC)—were implemented for the classification of the lignin samples. The DTC model exhibited the highest accuracy among them across different spectrometers. Although the benchtop spectrometer produced the most precise outcomes, the compact NeoSpectra system also displayed potential as a cost-efficient option. Nonetheless, the restricted spectral coverage of the handheld NIRONE spectrometer resulted in reduced classification accuracy. Our discoveries highlight the capability of NIR spectroscopy, combined with robust data analysis techniques, for the swift and non-destructive classification of technical lignins, facilitating their improved utilization in sustainable fields.
KW - Technical lignins
KW - NIR spectroscopy
KW - Classification
KW - Machine-learning
KW - PCA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634518
DO - https://doi.org/10.1016/j.chemolab.2025.105467
SN - 0169-7439
VL - 264
SP - 1
EP - 10
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-63451
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bui, Minh
A1 - Heinekamp, Christian
A1 - Fuhry, Emil
A1 - Weidner, Steffen
A1 - Radnik, Jörg
A1 - Ahrens, Mike
A1 - Scheurell, Kerstin
A1 - Balasubramanian, Kannan
A1 - Emmerling, Franziska
A1 - Braun, Thomas
T1 - Lewis-acid induced mechanochemical degradation of polyvinylidene fluoride: transformation into valuable products
N2 - Polyvinylidene fluoride (–[CH2CF2]n–, PVDF) waste poses significant environmental challenges due to its recalcitrant nature and widespread use. This study addresses the end-of-life management of PVDF by introducing a novel, sustainable mechanochemical approach for its valorisation. We investigated the degradation of PVDF into value-added materials using ball milling with anhydrous AlCl3 to achieve a quantitative mineralisation producing AlF3 and halide-functionalised graphite, along with gaseous products (HCl and CH4). Mechanistic key steps involve Lewis-acid catalysed C–F bond activation, dehydrofluorination and aromatisation. This approach provides an effective solution for PVDF waste management while offering a promising route for the production of high-value materials from polymer waste streams. Our findings contribute to sustainable practices in polymer recycling and resource recovery, respond to pressing environmental concerns associated with fluoropolymer disposal, and demonstrate the potential to convert polymer wastes into useful products.
KW - Mechanochemistry
KW - Polyvinylidenfluoride
KW - Degradation
KW - Ball mill
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649015
DO - https://doi.org/10.1039/d5sc05783c
SN - 2041-6520
VL - 16
IS - 40
SP - 18903
EP - 18910
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - About Polycondensation, Disproportionation, and Cyclization of Acetylated Poly(L-Lactide) Esters
N2 - L-lactide (LA) is polymerized with ethyl L-lactate or trifluoroethanol as initiators (LA/In = 30/1), and the resulting poly(L-lactide) esters are acetylated with acetic anhydride. The acetylated PLA esters are mixed with SnOct2, dibutyltin bis(4-chlorophenoxide), or dibutyltin bis(pentafluorophenoxide) in solution and crystallized at 120 °C. The doped crystals are annealed at 140 °C or at 160 °C for 7, 14, and 28 days, and the chemical modifications that occurred in the solid state are monitored by matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC), and differential scanning calorimetry (DSC) measurements. All catalysts promoted polycondensation, while no significant formation of cycles is observed. However, in the presence of SnOct2, disproportionation of chains occurred upon annealing at 120 or 140 °C, and crystallites consisting of extended chains with Mn values ≈3500 – 3600 and low dispersities (Ð < 1.5) are formed.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Polylactides
KW - Transesterifcation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630349
DO - https://doi.org/10.1002/macp.202400175
SN - 1521-3935
VL - 225
IS - 19
PB - Wiley VHC-Verlag
AN - OPUS4-63034
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stolar, Tomislav
A1 - Bayram, Dilara
A1 - May, Anastasia
A1 - Sundermann, Remie
A1 - Prinz, Carsten
A1 - Meyer, Klas
A1 - Myxa, Anett
A1 - Falkenhagen, Jana
A1 - Emmerling, Franziska
T1 - Selective mechanochemical conversion of post-consumer polyethylene terephthalate waste into hcp and fcu UiO-66 metal–organic frameworks
N2 - Single-use plastics strongly contribute to plastic pollution, and less than 10% of plastic waste is recycled globally. Here, we present a selective mechanochemical protocol for converting post-consumer polyethylene terephthalate (PET) transparent bottles and coloured textile waste into the porous metal–organic framework (MOF) UiO-66 materials. We used time-resolved in situ (TRIS) synchrotron powder X-ray diffraction and Raman spectroscopy to monitor the depolymerization of PET during ball milling. To convert disodium terephthalate to UiO-66, we developed base and base-free synthetic routes that lead to fcu and hcp UiO-66 phases, respectively, including the first ever synthesis of hcp UiO-66 by mechanochemistry. Our results demonstrate the potential of mechanochemistry to selectively access fcu and hcp UiO-66 phases using post-consumer PET waste.
KW - Mechanochemistry
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653958
DO - https://doi.org/10.1039/D4MR00126E
SN - 2976-8683
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65395
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Schwab, Alexander
A1 - Carraro, Francesco
A1 - Tavernaro, Isabella
A1 - Falkenhagen, Jana
A1 - Villajos, Jose
A1 - Falcaro, Paolo
A1 - Emmerling, Franziska
T1 - ZIF-8-based biocomposites via reactive extrusion: towards industrial-scale manufacturing
N2 - Mechanochemistry, a sustainable synthetic method that minimizes solvent use, has shown great promise in producing metal–organic framework (MOF)-based biocomposites through ball milling. While ball milling offers fast reaction times, biocompatible conditions, and access to previously unattainable biocomposites, it is a batch-type process typically limited to gram-scale production, which is insufficient to meet commercial capacity. We introduce a scalable approach for the continuous solid-state production of MOF-based biocomposites. Our study commences with model batch reactions to examine the encapsulation of various biomolecules into Zeolitic Imidazolate Framework-8 (ZIF-8) via hand mixing, establishing a foundation for upscaling. Subsequently, the process is scaled up using reactive extrusion, enabling continuous and reproducible kilogram-scale production of bovine serum albumin (BSA)@ZIF-8 with tunable protein loading. Furthermore, we achieve the one-step formation of shaped ZIF-8 extrudates encapsulating clinical therapeutic hyaluronic acid (HA). Upon release of HA from the composite, the molecular weight of HA is preserved, highlighting the industrial potential of reactive extrusion for the cost-effective and reliable manufacturing of biocomposites for drug-delivery applications.
KW - Mechanochemistry
KW - Extrusion
KW - Biocompoites
KW - MOFs
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654777
DO - https://doi.org/10.1039/D5TA08276E
SN - 2050-7496
SP - 1
EP - 14
PB - Royal Society of Chemistry
AN - OPUS4-65477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, Andreas
T1 - Poly(butylene terephthalate): About condensation, cyclization, degradation and elimination reactions in the solid state, and the role of smooth crystal surfaces
N2 - Three commercial poly(butylene terephthalate) (PBT) samples - Pocan B1300 (B13), Pocan B1600 (B16), and Addigy P 1210 (AP121) - served as the starting materials for the annealing experiments, which were conducted with and without the addition of esterification and transesterification catalysts. The catalysts used were Sn(II) 2-ethylhexanoate (SnOct₂), Zr(IV) acetylacetonate, and 4-toluene sulfonic acid (TSA). Temperatures varied between 150 and 210 °C. The PBT samples were characterized using differential scanning calorimetry (DSC), gel permeation chromatography (GPC), small-angle X-ray scattering (SAXS), and matrix-assisted laser desorption/ionization time-of-flight (MALDI TOF) mass spectrometry. The MALDI mass spectra of all three samples differed greatly but displayed mass peaks of cycles. Similar results were produced by annealing with SnOct₂ or Zr(acac)₄, which favored the formation of even-numbered cycles within the mass range below m/z 5000, along with slow degradation. TSA favored a more intensive degradation without the formation of cycles or even with the destruction of cycles. PBT chains with two carboxylic (COOH) end groups were the most stable species under all circumstances. The origin of the extremely high melting point of AP121 (241–242 °C) can be explained by the smoothing of crystallite surfaces via transesterification. The results suggest that combining MALDI mass spectrometry and SAXS measurements provides a new way to better understand the solid-state chemistry of PBT and related polyesters.
KW - MALDI-TOF MS
KW - Polybutylene Terephthalate
KW - Crystallization
KW - solid state
KW - cyclization
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652844
DO - https://doi.org/10.1016/j.polymdegradstab.2025.111862
SN - 0141-3910
VL - 245
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-65284
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dalgic, Mete‐Sungur
A1 - Kumar, Sourabh
A1 - Weidner, Steffen
T1 - Quantitative Analysis of Polymers by MALDI‐TOF Mass Spectrometry: Correlation Between Signal Intensity and Arm Number
N2 - The signal intensities of linear and star‐shaped poly(L‐lactides) (PLA) and poly (ethylene oxides) (PEO) were compared to determine the influence of the number of arms on the ionization in matrix‐assisted laser desorption/ionization time‐of‐flight (MALDI‐TOF) mass spectrometry. In this study, a variety of blends were prepared and investigated, including binary and ternary combinations of linear and star‐shaped polymers with similar molecular masses. The focus was on examining their intensity ratios. In equimolar binary PLA blends, polymer stars were observed to exhibit higher intensities than their linear counterparts. This result was supported by experiments with equimolar ternary PLA blends, which clearly demonstrated an intensity dependence on the number of polymer arms. It was observed that four‐arm PLA exhibited higher intensities than three‐arm PLA. A similar trend was observed in investigations involving acetylated polymer end groups, suggesting that differences in ionization are primarily influenced by polymer architecture rather than end groups. In order to validate this assumption, the binding energies for [polymer‐K] + adduct ions utilizing the most stable geometry obtained from GOAT (Global Optimizer Algorithm) were calculated, revealing that star‐shaped lower mass oligomers have slightly higher binding energies.
KW - MALDI-TOF MS
KW - Starlike polymers
KW - Quantification
KW - Topology
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653401
DO - https://doi.org/10.1002/jms.70023
SN - 1076-5174
VL - 61
IS - 1
SP - 1
EP - 12
PB - John Wiley & Sons Ltd.
AN - OPUS4-65340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, Andreas
A1 - Falkenhagen, Jana
A1 - Kricheldorf, Hans R.
T1 - Cyclic polyglycolide by means of metal acetylacetonates
N2 - Glycolide was polymerized in bulk at 160 °C using various metal acetylacetonates as catalysts. Zirconium acetylacetonate was particularly efficient, enabling rapid polymerization even at 130 °C. The formation of cyclic poly(glycolic acid) (PGA), most likely via a ring-expansion polymerization (REP) mechanism, was proven by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry. Depending on the polymerization conditions, the formation of even-numbered cycles was favored to varying degrees. Number-average molecular weights (Mn) in the range of 2000–3500 g mol−1 were achieved with dispersities below 2.0. Wide-angle X-ray scattering (WAXS) powder patterns showed that the crystal lattice was the same as that of known linear PGAs, regardless of the Mn values. These patterns enabled a comparison of crystallinities with values derived from DSC measurements.
KW - MALDI-TOF MS
KW - Polyglycolide
KW - Crystallization
KW - Small-angle X-ray scattering
KW - Cyclization
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653731
DO - https://doi.org/10.1039/d5ra07961f
SN - 2046-2069
VL - 16
IS - 2
SP - 1757
EP - 1764
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Elert, Anna Maria
A1 - Kanerva, M
A1 - Puolakka, A
A1 - Takala, T.M.
A1 - Mylläri, V
A1 - Jönkkäri, I
A1 - Sarlin, E
A1 - Seitsonen, J
A1 - Ruokolainen, J
A1 - Saris, P
A1 - Vuorinen, J
T1 - Antibacterial polymer fibres by rosin compounding and melt-spinning
N2 - The antibacterial features of natural pine/spruce rosin are well established, yet the functionality in various thermoplastics has not been surveyed. This work focuses on the processing of industrial grade purified rosin mixed with polyethylene (PE), polypropylene (PP), polylactic acid (PLA), polyamide (PA) and corn starch based biopolymer (CS). Homopolymer masterbatches were extrusion-compounded and melt-spun to form fibres for a wide range of products, such as filters, reinforcements, clothing and medical textiles. Due to the versatile chemical structure of rosin, it was observed compatible with all the selected polymers. In general, the rosin-blended systems were shear-thinning in a molten condition. The doped fibres spun of PE and PP indicated adequate melt-spinning capability and proper mechanical properties in terms of ultimate strength and Young's modulus. The antibacterial response was found dependent on the selected polymer. Especially PE with a 10 wt% rosin content showed significant antibacterial effects against Escherichia coli DH5α and Staphylococcus aureus ATCC 12598 when analysed in the Ringer's solution for 24 h.
KW - Rosin
KW - Antibacterial
KW - Thermoplastics
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481785
DO - https://doi.org/10.1016/j.mtcomm.2019.05.003
SN - 2352-4928
VL - 20
SP - 527
EP - 527
PB - Elsevier
AN - OPUS4-48178
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brzeska, J.
A1 - Elert, Anna Maria
A1 - Morawska, M.
A1 - Sikorska, W.
A1 - Kowalczuk, M.
A1 - Rutkowska, M.
T1 - Branched Polyurethanes Based on Synthetic Polyhydroxybutyrate with Tunable Structure and Properties
N2 - Branched, aliphatic polyurethanes (PURs) were synthesized and compared to linear analogues. The influence of polycaprolactonetriol and synthetic poly([R,S]-3-hydroxybutyrate) (R,S-PHB) in soft segments on structure, thermal and sorptive properties of PURs was determined.
Using FTIR and Raman spectroscopies it was found that increasing the R,S-PHB amount in the structure of branched PURs reduced a tendency of urethane groups to hydrogen bonding. Melting enthalpies (on DSC thermograms) of both soft and hard segments of linear PURs were higher than branched PURs, suggesting that linear PURs were more crystalline. Oil sorption by samples of linear and branched PURs, containing only polycaprolactone chains in soft segments, was higher than in the case of samples with R,S-PHB in their structure. Branched PUR without R,S-PHB absorbed the highest amount of oil. Introducing R,S-PHB into the PUR structure increased water sorption.
Thus, by operating the number of branching and the amount of poly([R,S]-3-hydroxybutyrate) in soft segments thermal and sorptive properties of aliphatic PURs could be controlled.
KW - IR
KW - Polyurethane
KW - PUR
KW - RAMAN
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457087
DO - https://doi.org/10.3390/polym10080826
VL - 10
IS - 8
SP - 826, 1
EP - 12
PB - MDPI
AN - OPUS4-45708
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yadav, Anur
A1 - Iost, R. M.
A1 - Neubert, T. J.
A1 - Baylan, S.
A1 - Schmid, Thomas
A1 - Balasubramanian, Kannan
T1 - Selective electrochemical functionalization of the graphene edge
N2 - We present a versatile and simple method using electrochemistry for the exclusive functionalization of the edge of a graphene monolayer with metal nanoparticles or polymeric amino groups. The attachment of metal nanoparticles allows us to exploit surface-enhanced Raman scattering to characterize the chemistry of both the pristine and the functionalized graphene edge. For the pristine patterned graphene edge, we observe the typical edge-related modes, while for the functionalized graphene edge we identify the chemical structure of the functional layer by vibrational fingerprinting. The ability to obtain single selectively functionalized graphene edges routinely on an insulating substrate opens an avenue for exploring the effect of edge chemistry on graphene properties systematically.
KW - Graphene
KW - Nanoparticles
KW - Nanosciences
KW - Surface-enhanced Raman scattering
KW - Atomic force microscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474357
DO - https://doi.org/10.1039/C8SC04083D
SN - 2041-6520
VL - 10
IS - 3
SP - 936
EP - 942
PB - Royal Society of Chemistry
AN - OPUS4-47435
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zettner, Alina
A1 - Gojani, Ardian
A1 - Schmid, Thomas
A1 - Gornushkin, Igor B.
T1 - Evaluation of a Spatial Heterodyne Spectrometer for Raman Spectroscopy of Minerals
N2 - Spatial heterodyne spectroscopy (SHS) is a novel spectral analysis technique that is being applied for Raman spectroscopy of minerals. This paper presents the theoretical basis of SHS and its application for Raman measurements of calcite, quartz and forsterite in marble, copper ore and nickel ore, respectively. The SHS measurements are done using a broadband (518–686 nm) and resolving power R ≈ 3000 instrument. The spectra obtained using SHS are compared to those obtained by benchtop and modular dispersive spectrometers. It is found that SHRS performance in terms of resolution is comparable to that of the benchtop spectrometer and better than the modular dispersive spectrometer, while the sensitivity of SHRS is worse than that of a benchtop spectrometer, but better than that of a modular dispersive spectrometer. When considered that SHS components are small and can be packaged into a handheld device, there is interest in developing an SHS-based Instrument for mobile Raman spectroscopy. This paper evaluates the possibility of such an application.
KW - Forsterite
KW - Spatial heterodyne spectrometer
KW - Interferometric spectroscopy
KW - Fourier transform spectroscopy
KW - Raman spectroscopy
KW - Calcite
KW - Quartz
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504624
DO - https://doi.org/10.3390/min10020202
VL - 10
IS - 2
SP - 202
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schäfer, N.
A1 - Chahine, G. A.
A1 - Wilkinson, A. J.
A1 - Schmid, Thomas
A1 - Rissom, T.
A1 - Schülli, T. U.
A1 - Abou-Ras, D.
T1 - Microstrain distributions in polycrystalline thin films measured by X-ray microdiffraction
N2 - Microstrain distributions were acquired in functional thin films by high-resolution X-ray microdiffraction measurements, using polycrystalline CuInSe2 thin films as a model system. This technique not only provides spatial resolutions at the submicrometre scale but also allows for analysis of thin films buried within a complete solar-cell stack. The microstrain values within individual CuInSe2 grains were determined to be of the order of 10^-4. These values confirmed corresponding microstrain distribution maps obtained on the same CuInSe2 layer by electron backscatter diffraction and Raman microspectroscopy.
KW - Microstrain distribution
KW - X-ray microdiffraction
KW - Polycrystalline thin films
KW - Raman microscopy
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-366592
DO - https://doi.org/10.1107/S1600576716003204
SN - 1600-5767
VL - 49
SP - 632
EP - 635
AN - OPUS4-36659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schmid, Thomas
A1 - Dariz, P.
ED - Ziemann, M.
T1 - Raman band widths of anhydrite II reveal the burning history of high-fired medieval gypsum mortars
N2 - The use of high-fired gypsum as binder for masonry and joint mortars or stuccowork in Central Europe in the Early and High Middle Ages was a regional specific as it depended on local gypsum deposits. The calcination technology possible at the time resulted in an assemblage of calcium sulphate phases dehydrated to different degrees and partly thermally damaged accessory minerals of the raw gypsum. Because of the absence of medieval textbooks, the observation of high-temperature, low-pressure mineral transformations and the correlation of phases coexisting in not hydrated binder relicts in the gypsum matrix to the mineralogy of the raw material and the burning conditions constitute the only source to the historical technological know-how.
The CaSO4–H2O system consists of five crystalline phases, which can be discriminated by structural analysis methods, such as Raman spectroscopy, due to obvious differences in their spectroscopic data: gypsum (CaSO4 ⋅ 2 H2O), bassanite (hemihydrate, CaSO4 ⋅ ½ H2O), anhydrite III (CaSO4), anhydrite II (CaSO4), and anhydrite I (CaSO4). Only recently, it was possible to demonstrate that small spectroscopic variations exist also within the relatively large stability range of anhydrite II from approx. 180°C to 1180°C: all Raman bands narrow with increasing burning temperature applied in the synthesis from gypsum powder. The determination of band widths of down to 3 cm-1 and differences between them of a few tenths of a wavenumber is not a trivial task. Thus, this contribution discusses peak fitting and strategies for correction of instrument-dependent band broadening.
Raman maps of polished thin sections of gypsum mortars provide access to the burning histories of individual remnant thermal anhydrite grains and enable the discrimination of natural anhydrite originating from the gypsum deposit. This novel analytical method was applied to samples from medieval South Tyrolean stucco decorations and sculptures. Beyond that, Raman microspectroscopy was employed for following pyrometamorphic reactions in natural impurities of the raw material. In the presented examples mineral thermometry indicates process temperatures above 800°C: the breakdown of magnesium-rich chlorite led to the formation of forsterite Mg2SiO4, while the thermal decomposition of dolomite CaMg(CO3)2 yielded – after hydration and carbonation – magnesite MgCO3, CaCO3 polymorphs and magnesian calcite. Lower burning temperatures, which leave the accessory minerals in their pristine form, can be traced by measuring the spectra of anhydrite crystalites in grains of firing products and evaluating Raman band widths. Throughout the applications of this analytical method so far, calcination temperatures ranging from approx. 600°C to 900°C were determined.
T2 - 10th International Congress on the Application of Raman Spectroscopy in Art and Archaeology
CY - Potsdam, Germany
DA - 03.09.2019
KW - Raman microspectroscopy
KW - High-fired medieval gypsum mortars
KW - Raman band width
KW - Gypsum dehydration
KW - Thermal anhydrite
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496204
SP - 36
EP - 37
PB - University of Potsdam
CY - Potsdam
AN - OPUS4-49620
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kern, Simon
A1 - Michalik-Onichimowska, Aleksandra
A1 - Riedel, Jens
A1 - Panne, Ulrich
A1 - King, R.
A1 - Maiwald, Michael
ED - Herwig, Christoph
T1 - “Click” analytics for “click” chemistry – a simple method for calibration-free evaluation of online NMR spectra
N2 - Currently, research in chemical manufacturing moves towards flexible plug-and-play approaches focusing on modular plants, capable of producing small scales on-demand with short down-times between individual campaigns. This approach allows for efficient use of hardware, a faster optimization of the process conditions, and thus, an accelerated introduction of new products to the market. Driven mostly by the search for chemical syntheses under biocompatible conditions, so-called “click” chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques.
Here we report on a fast and reliable calibration-free online high field NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement with a time interval of 20 s per spectrum, and a robust, automated algorithm to interpret the obtained data. All spectra were acquired using a 500 MHz NMR spectrometer (Varian) with a dual band flow probe having a 1/16-inch polymer tubing working as a flow cell. Single scan 1H NMR spectra were recorded with an acquisition time of 5 s, relaxation delay of 15 s. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in non-deuterated solvents while its time-resolved behaviour was characterised with step tracer experiments.
Through the application of spectral modeling the signal area for each reactant can be deconvoluted in the online spectra and thus converted to the respective concentrations or molar ratios. The signals which were suitable for direct integration were used herein for comparison purposes of both methods.
T2 - 11. Interdisziplinäres Doktorandenseminar
CY - Berlin, Germany
DA - 12.03.2017
KW - Process Monitoring
KW - Online NMR Spectroscopy
KW - Indirect Hard Modeling
KW - Process Control
KW - Process Analytical Technology
KW - CONSENS
KW - Click Chemistry
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435531
SP - 33
EP - 35
PB - Gesellschaft Deutscher Chemiker (GDCh)
CY - Frankfurt a. M.
AN - OPUS4-43553
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zou, T.
A1 - Nonappa, N.
A1 - Khavani, M.
A1 - Vuorte, M.
A1 - Penttilä, P.
A1 - Zitting, A.
A1 - Valle-Delgado, J. J.
A1 - Elert, Anna Maria
A1 - Silbernagl, Dorothee
A1 - Balakshin, M.
A1 - Sammalkorpi, M.
A1 - Österberg, M.
T1 - Experimental and Simulation Study of the Solvent Effects on the Intrinsic Properties of Spherical Lignin Nanoparticles
N2 - Spherical lignin nanoparticles (LNPs) fabricated via nanoprecipitation of dissolved lignin are among the most attractive biomass-derived nanomaterials. Despite various studies exploring the methods to improve the uniformity of LNPs or seeking more application opportunities for LNPs, little attention has been given to the fundamental aspects of the solvent effects on the intrinsic properties of LNPs. In this study, we employed a variety of experimental techniques and molecular dynamics (MD) simulations to investigate the solvent effects on the intrinsic properties of LNPs. The LNPs were prepared from softwood Kraft lignin (SKL) using the binary solvents of aqueous acetone or aqueous tetrahydrofuran (THF) via nanoprecipitation. The internal morphology, porosity, and mechanical properties of the LNPs were analyzed with electron tomography (ET), small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and intermodulation AFM (ImAFM). We found that aqueous acetone resulted in smaller LNPs with higher uniformity compared to aqueous THF, mainly ascribing to stronger solvent−lignin interactions as suggested by MD simulation results and confirmed with aqueous 1,4-dioxane (DXN) and aqueous dimethyl sulfoxide (DMSO).
More importantly, we report that both LNPs were compact particles with relatively homogeneous density distribution and very low porosity in the internal structure. The stiffness of the particles was independent of the size, and the Young’s modulus was in the range of 0.3−4 GPa. Overall, the fundamental understandings of LNPs gained in this study are essential for the design of LNPs with optimal performance in applications.
KW - Lignin
KW - Electron tomography
KW - Intermodulation AFM
KW - Modulus
KW - SAXS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546948
DO - https://doi.org/10.1021/acs.jpcb.1c05319
SN - 1520-5207
VL - 125
IS - 44
SP - 12315
EP - 12328
PB - ACS
AN - OPUS4-54694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dariz, P.
A1 - Schmid, Thomas
T1 - Raman focal point on Roman Egyptian blue elucidates disordered cuprorivaite, green glass phase and trace compounds
N2 - The discussed comparative analyses of Roman Imperial pigment balls and fragmentary murals unearthed in the ancient cities of Aventicum and Augusta Raurica (Switzerland) by means of Raman microspectroscopy pertain to a predecessor study on trace compounds in Early Medieval Egyptian blue (St. Peter, Gratsch, South Tyrol, Northern Italy). The plethora of newly detected associated minerals of the raw materials surviving the synthesis procedure validate the use of quartz sand matching the composition of sediments transported by the Volturno river into the Gulf of Gaeta (Campania, Southern Italy) with a roasted sulphidic copper ore and a mixed-alkaline plant ash as fluxing agent. Thus, the results corroborate a monopolised pigment production site located in the northern Phlegrean Fields persisting over the first centuries A.D., this in line with statements of the antique Roman writers Vitruvius and Pliny the Elder and recent archaeological evidences. Beyond that, Raman spectra reveal through gradual peak shifts and changes of band width locally divergent process conditions and compositional inhomogeneities provoking crystal lattice disorder in the chromophoric cuprorivaite as well as the formation of a copper-bearing green glass phase, the latter probably in dependency of the concentration of alkali flux, notwithstanding that otherwise solid-state reactions predominate the synthesis.
KW - Raman microspectroscopy
KW - Egyptian blue
KW - Cuprorivaite
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559028
DO - https://doi.org/10.1038/s41598-022-19923-w
SN - 2045-2322
VL - 12
IS - 1
SP - 1
EP - 12
PB - Nature Publishing Group
CY - London
AN - OPUS4-55902
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Hidde, Julia
A1 - Grünier, Sophie
A1 - Jungnickel, Robert
A1 - Dariz, P.
A1 - Riedel, Jens
A1 - Neuhaus, B.
T1 - Ageing effects in mountig media of microscope slide samples from natural history collections: A case study with Canada balsam and Permount™
N2 - Microscope slide collections represent extremely valuable depositories of research material in a natural history, forensic, veterinary, and medical context. Unfortunately, most mounting media of these slides deteriorate over time, with the reason for this not yet understood at all. In this study, Raman spectroscopy, ultraviolet–visible (UV–Vis) spectroscopy, and different types of light microscopy were used to investigate the ageing behaviour of naturally aged slides from museum collections and the experimentally aged media of Canada balsam and Permount™, representing a natural and a synthetic resin, respectively, with both being based on mixtures of various terpenes. Whereas Canada balsam clearly revealed chemical ageing processes, visible as increasing colouration, Permount™ showed physical deterioration recognisable by the increasing number of cracks, which even often impacted a mounted specimen. Noticeable changes to the chemical and physical properties of these mounting media take decades in the case of Canada balsam but just a few years in the case of Permount™. Our results question whether or not Canada balsam should really be regarded as a mounting medium that lasts for centuries, if its increasing degree of polymerisation can lead to a mount which is no longer restorable.
KW - Deterioration
KW - Microscope slides
KW - Mounting media
KW - Raman spectroscopy
KW - UV–Vis spectroscopy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537632
DO - https://doi.org/10.3390/polym13132112
VL - 13
IS - 13
SP - 1
EP - 27
PB - MDPI
CY - Basel
AN - OPUS4-53763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goedecke, C.
A1 - Eisentraut, Paul
A1 - Altmann, Korinna
A1 - Elert, Anna Maria
A1 - Bannick, C. G.
A1 - Ricking, M.
A1 - Obermaier, N.
A1 - Barthel, A.-K.
A1 - Schmitt, T.
A1 - Jekel, M.
A1 - Braun, U.
T1 - Development of a routine screening method for the microplastic mass content in a wastewater treatment plant effluent
N2 - An investigation of microplastic (MP) occurrence in a municipal wastewater treatment plant (WWTP) effluent with tertiary treatment was carried out. Representative sample volumes of 1 m3 were taken by applying a fractionated filtration method (500, 100, and 50 µm mesh sizes). The detection of MP mass fractions by thermal extraction desorption–gas chromatography/mass spectrometry (TED-GC/MS) was achieved without the previously required additional sample pretreatment for the first time. Different types of quantification methods for the evaluation of TED-GC/MS data were tested, and their accuracy and feasibility have been proven for real samples. Polyethylene, polystyrene, and polypropylene were identified in effluent samples. The polymer mass content varied significantly between 5 and 50 mg m−3. A correlation between the MP load and the quantity of suspended matter in the WWTP effluents, particle size distribution, particle type, and operation day (i.e., weekday, season, and capacity) was not found. It can be concluded that a meaningful assessment of WWTPs requires a comprehensive sampling campaign with varying operation conditions.
KW - Microplastic
KW - Waste water treatment
KW - Thermoanalytics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550862
DO - https://doi.org/10.3389/fenvc.2022.844633
SN - 2673-4486
VL - 3
SP - 1
EP - 10
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-55086
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schutter, Jan David
A1 - Eberhardt, Karl
A1 - Elert, Anna Maria
A1 - Radnik, Jörg
A1 - Geißler, Daniel
A1 - Özcan Sandikcioglu, Özlem
T1 - Synthesis and characterization of lipopolysaccharide (LPS) anchored polystyrene microparticles as a synthetic model system for attachment studies
N2 - Outer membrane lipopolysaccharides (LPS) play a crucial role in determining attachment behavior and pathogenicity of bacteria. The aim of this study was to develop a simple procedure for anchoring bacterial lipopolysaccharides to polystyrene (PS) microparticles as a model system for in situ attachment studies. By using a swellcapture methodology, commercially available LPS of Pseudomonas aeruginosa (strain ATCC 27316 serotype 10.22) was anchored onto PS microparticles in a proof-of-concept study. A detailed chemical and morphological characterization has proven the success of LPS incorporation. It was shown that the coverage and structure of the LPS film was concentration dependent. The procedure can easily be adapted to LPS of other bacterial strains to generate a synthetic model toolkit for attachment studies.
KW - Bacterial lipopolysaccharides
KW - Pseudomonas aeruginosa
KW - Polystyrene microparticles
KW - Swell-capture
KW - Biomimicry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579818
DO - https://doi.org/10.1016/j.colsurfb.2023.113301
SN - 0927-7765
VL - 226
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-57981
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Jens
A1 - Hufgard, Josefin
A1 - You, Yi
T1 - LIBS at high duty-cycles: effect of repetition rate and temporal width on the excitation laser pulses
N2 - Laser-induced breakdown spectroscopy (LIBS) is becoming a more mature technology every year with new variants such as laser ablation molecular isotopic spectrometry, reheating by various discharge techniques, and multiple pulse excitation schemes, in which sometimes lasers of different pulse lengths are used. However, lasers with inherent parameters like pulse length and repetition rate are still almost exclusively employed. Recent years have witnessed the advent of novel high-repetition-rate laser concepts for machining processes, like welding, milling, and engraving. Here, a comprehensive study of single-pulse LIBS spectra of a single aluminum target is presented to showcase the applicability of flexible high duty-cycle master oscillator power amplifier (MOPA) lasers. Although traditional flashlamp-pumped Fabry–Pérot lasers only permit a variation in the pulse energy and are operated at very low duty-cycles, MOPA lasers add repetition rate and pulse length as variable parameters. A thorough analysis of the temporal plasma behavior revealed the emission dynamic to closely match the excitation laser pulse pattern. An aluminum sample’s spectral response was shown to be significantly impacted by variations in both rate and length. Although the spectral emission strength of the elemental lines of Al, Sr, and Ca all peaked at slightly different parameter settings, the strongest impact was found on the relative abundance of molecular AlO bands. Unlike in previous laser ablation molecular isotopic spectrometry (LAMIS) publications, the latter could be readily detected with a good intensity and well-resolved spectral features without any temporal gating of the detector. This finding, together with the fact that MOPA lasers are both inexpensive and dependable, makes for a promising combination for future studies including the detection of diatomic band structures.
KW - Laser-induced breakdown spectroscopy
KW - LIBS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583300
DO - https://doi.org/10.3389/fphy.2023.1241533
SN - 2296-424X
VL - 11
SP - 1
EP - 8
AN - OPUS4-58330
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Casperson, Ralf
A1 - Friedrich, Alexander
A1 - Heckel, Thomas
A1 - Zhang, Tianyun
T1 - Verwendung von DICONDE bei der Eisenbahn-Schienenprüfung
N2 - Bei der zerstörungsfreien Prüfung verlegter Eisenbahnschienen werden die Rohdaten derzeit in proprietären Datenformaten gespeichert und auf Datenträgern zwischen den Prüfzügen und den auswertenden Stellen versendet. Die proprietären Datenformate sind in der Regel nur den Herstellern der Prüfsysteme bekannt und deren Dokumentation nicht allgemein zugänglich.
Die „Standard Practice for Digital Imaging and Communication in Nondestructive Evaluation“ (DICONDE), basierend auf dem medizinischen Standard „Digital Imaging and Communication in Medicine“ (DICOM), ermöglicht es, sowohl Prüfdaten als auch Prüfergebnisse und Streckeninformationen in einem standardisierten Format zu speichern und zwischen verschiedenen Endpunkten zu übertragen.
Das Poster gibt zunächst einen kurzen Überblick über die hierarchische Struktur von DICONDE und zeigt dann, wie DICONDE bei der Prüfung verlegter Eisenbahnschienen verwendet werden kann. Die geometrischen Besonderheiten (mehrere Kilometer Länge pro Prüffahrt, kurviger Streckenverlauf) stellen dabei eine besondere Herausforderung dar. Im Rahmen des mFUND-geförderten Projektes „Arteficial Intelligence for Railway Inspection (AIFRI)“, Förderkennzeichen 19FS2014C, wurde ein Vorschlag für eine Erweiterung des DICONDE-Standards für die Schienenprüfung erarbeitet und bei der ASTM eingereicht.
T2 - DGZfP Jahrestagung 2024
CY - Osnabrück, Germany
DA - 05.05.2024
KW - DICONDE
KW - Eisenbahn
KW - Schienenprüfung
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600204
DO - https://doi.org/10.58286/29500
SP - 1
EP - 5
PB - NDT.net
AN - OPUS4-60020
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Friedrich, Alexander
T1 - Simulation of Eddy Current Rail Testing Data for Neural Networks
N2 - The present work is part of the AIFRI project (Artificial Intelligence For Rail Inspection), where we and our project partners train a neural network for defect detection and classification. Our goal at BAM is to generate artificial ultrasound and eddy current training data for the A.I. This paper has an exploratory nature, where we focus on the simulation of eddy current signals for head check cracks, one of the most important rail surface defects. The goal of this paper is twofold. On the one hand, we present our general simulation setup. This includes geometric models for head check cracks with features like branching and direction change, a model for the HC10 rail testing probe, and the configuration of the Faraday simulation software.
On the other hand, we use the Faraday software to simulate eddy current testing signals with a strong focus on the influence of the damage depth on the signal, while differentiating between different crack geometries. Here, we observe an early saturation effect of the test signal at a damage depth of 2 mm (at a crack angle of 25◦ to the surface). That is about 2 mm earlier than we would expect from measurements at a crack angle of 90◦. This behavior will be investigated further in a future paper. Finally, we interpolate the simulated signals in a two-step curve fitting process. With these interpolations we may generate eddy current test signals for any damage depth within the simulated range.
T2 - 13th European Conference on Non-Destructive Testing 2023
CY - Lisbon, Portugal
KW - Artificial Intelligence
KW - Simulation
KW - Eddy Current
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581918
DO - https://doi.org/10.58286/28179
SN - 1435-4934
VL - 28
IS - 8
SP - 1
EP - 6
PB - NDT.net
CY - Kirchwald
AN - OPUS4-58191
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gawek, Marcel
A1 - Szymoniak, Paulina
A1 - Hülagü, Deniz
A1 - Hertwig, Andreas
A1 - Schönhals, Andreas
T1 - Molecular Mobility of Thin Films and the Adsorbed Layer of Poly(2-vinylpyridine)
N2 - The molecular dynamics of thin films and the adsorbed layer of poly(2-vinylpyridine) (P2VP) were investigated using broadband dielectric spectroscopy (BDS) and spectroscopic ellipsometry. Thin films of P2VP were prepared on silicon substrates and characterized to understand the influence of film thickness on the thermal glass transition temperature (Tg) and molecular mobility. The ellipsometric study revealed a decrease in Tg with decreasing film thickness, attributed to the enhanced mobility at the polymer/air interface. The adsorbed layer, prepared via the solvent leaching approach, exhibited a higher Tg compared to the bulk, indicating reduced molecular mobility due to strong polymer substrate interactions. The dielectric measurements were carried out in two different electrode configurations, crossed electrode capacitors (CEC) and nanostructured electrodes (NSE), where the latter allows for a free surface layer at the polymer/air interface. The relaxation rates of the α-relaxation measured in the CEC geometry collapse into one chart independent from the film thickness. For the thin films measured in the NSE arrangement the relaxation rates slow down with decreasing film thickness which was discussed as related to a stronger interaction of the P2VP segments with the native SiO2 at the surface of the silicon substrate compared to aluminum. It is worth to note that the effect of the enhanced mobility at the polymer/air interface is not observed in the dielectric measurements. BDS measurements in NSE geometry identified an additional relaxation process (α*-relaxation) in thin films, which was more pronounced in the adsorbed layer. This process is hypothesized to be related to molecular fluctuations within the adsorbed layer including the adsorption/desorption dynamics of segments or to a Slow Arrhenius Process (SAP) related to the equilibration dynamics deep in the glassy state.
KW - Thin polymer films
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637181
DO - https://doi.org/10.1039/d5sm00539f
SN - 1744-6848
SP - 1
EP - 12
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63718
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kirner, Sabrina V.
A1 - Slachciak, Nadine
A1 - Elert, Anna Maria
A1 - Griepentrog, Michael
A1 - Fischer, Daniel
A1 - Hertwig, Andreas
A1 - Sahre, Mario
A1 - Dörfel, Ilona
A1 - Sturm, Heinz
A1 - Pentzien, Simone
A1 - Koter, Robert
A1 - Spaltmann, Dirk
A1 - Krüger, Jörg
A1 - Bonse, Jörn
T1 - Tribological performance of titanium samples oxidized by fs-laser radiation, thermal heating, or electrochemical anodization
N2 - Commercial grade-1 titanium samples (Ti, 99.6%) were treated using three alternative methods, (i) femtosecond laser processing, (ii) thermal heat treatment, and (iii) electrochemical anodization, respectively, resulting in the formation of differently conditioned superficial titanium oxide layers. The laser processing (i) was carried out by a Ti:sapphire laser (pulse duration 30 fs, central wavelength 790 nm, pulse repetition rate 1 kHz) in a regime of generating laser-induced periodic surface structures (LIPSS). The experimental conditions (laser fluence, spatial spot overlap) were optimized in a sample-scanning setup for the processing of several square-millimeters large surface areas covered homogeneously by these nanostructures. The differently oxidized titanium surfaces were characterized by optical microscopy, micro Raman spectroscopy, variable angle spectroscopic ellipsometry, and instrumented indentation testing. The tribological performance was characterized in the regime of mixed friction by reciprocating sliding tests against a sphere of hardened steel in fully formulated engine oil as lubricant. The specific tribological performance of the differently treated surfaces is discussed with respect to possible physical and chemical mechanisms.
KW - Femtosecond laser
KW - Titanium
KW - Oxidation
KW - Friction
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-445609
DO - https://doi.org/10.1007/s00339-018-1745-8
SN - 0947-8396
SN - 1432-0630
VL - 124
IS - 4
SP - 326, 1
EP - 10
PB - Springer-Verlag
AN - OPUS4-44560
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zöllner, Moritz
A1 - Dariz, Petra
A1 - Riedel, Jens
A1 - Schmid, Thomas
T1 - Dolomite and Mg Calcite as Mineral Thermometers in Mortar Binders. A High Resolution Raman Spectroscopic Study
N2 - This paper suggests the use of high‐resolution Raman scattering bands of MgCa carbonates as posteriori thermometer minerals in archaeometric studies. Therefore, the thermal behavior of two dolomite samples and the hydration and carbonation reaction in air of the decomposition products were investigated by Raman microspectroscopy. The increase in the calcination temperature resulted in the formation of – Raman silent MgO and – inert Mg calcite at 700°C–750°C. In contrast, the decarbonation, hydration, and recarbonation of sample material exposed to 750°C–900°C in a muffle furnace led to the appearance of Mg‐free calcite. High spectral resolution Raman spectroscopy enabled a spectral distinction between these two groups due to differences in the band parameters (peak position, bandwidth) of the vibrational (v1, v4, L) modes of calcite. In combination with Raman microspectroscopic mapping, this spectral information represents a new approach for the estimation of burning temperatures of medieval high‐fired gypsum mortars via natural dolomite impurities. Thus, the results of this work highlight the importance and potential of Raman microspectroscopy as a thermometric tool for elucidating the thermal history of anthropogenic fired materials, with potential applications for archaeometry and art technology, as well as for quality controls in the frame of the production of mineral mortar binders and ceramics or bricks, respectively.
KW - Mineral thermometry
KW - Raman spectroscopy
KW - Dolomite
KW - High-fired gypsum mortar
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630270
DO - https://doi.org/10.1002/jrs.6810
SN - 1097-4555
SP - 1
EP - 13
PB - Wiley
AN - OPUS4-63027
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Danischewski, Julia
A1 - Molnar, Brian
A1 - Riedel, Jens
A1 - Shelley, Jacob
T1 - Manipulation of Gaseous Ions with Acoustic Fields at Atmospheric Pressure
N2 - The ability to controllably move gaseous ions is an essential aspect of ion-based spectrometry (e.g., mass spectrometry and ion mobility spectrometry) as well as materials processing. At higher pressures, ion motion is largely governed by diffusion and multiple collisions with neutral gas molecules. Thus, high-pressure ion optics based on electrostatics require large fields, radio frequency drives, complicated geometries, and/or partially transmissive grids that become contaminated. Here, we demonstrate that low-power standing acoustic waves can be used to guide, block, focus, and separate beams of ions akin to electrostatic ion optics. Ions preferentially travel through the static-pressure regions (“nodes”) while neutral gas does not appear to be impacted by the acoustic field structure and continues along a straight trajectory. This acoustic ion manipulation (AIM) approach has broad implications for ion manipulation techniques at high pressure, while expanding our fundamental understanding of the behavior of ions in gases.
KW - Ion mobility spectrometry
KW - Acoustic
KW - Mass spectrometry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600704
DO - https://doi.org/10.1021/jacs.4c01224
SP - 1
EP - 6
PB - ACS Publications
AN - OPUS4-60070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xue, Boyang
A1 - Wang, Zhangjun
A1 - Zhu, Tao
A1 - Gu, Yezhen
A1 - Sun, Weihong
A1 - Chen, Chao
A1 - Li, Zhigang
A1 - Riedel, Jens
A1 - You, Yi
T1 - High repetition-rate laser-induced breakdown spectroscopy combined with two-dimensional correlation method for analysis of sea-salt aerosols
N2 - Laser-induced breakdown spectroscopy (LIBS) offers a tantalizing glimpse into real-time, on-the-spot aerosol analysis. Yet, the reliance on traditional lasers, with their limitations in energy and frequency, hampers optimal sample handling, dissociation, and excitation. To address those challenges, we propose a novel tactic: utilize a high repetition-rate (rep.-rate) laser with low pulse energy in combination with the two-dimensional correlation (2D-corr.) technique for sea-salt aerosols analyses. By examining the emission patterns from both the laser pulse train and individual pulses, we recognize distinctive analyte-specific rep.-rate responses, which allowed spectral reconstruction of analytes, avoiding background interferences. This discovery enabled the rep.-rate modulation for a 2D-corr. spectroscopy workflow. Consequently, we successfully differentiated between particle-related and air-species-related spectral components, obviating expensive spectrometers or intensified image detectors. For instance, the Na I at 589 nm stemming from aerosols exhibited an entirely different correlation contribution compared to O I at 777 nm, resulting in reconstructed clean aerosol-spectra without spectral peaks originated from air species. This 2D-corr. aerosol LIBS approach shows promising analytical potential streamlining aerosol particle analysis.
KW - LIBS
KW - Aerosol
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613392
DO - https://doi.org/10.1016/j.sab.2024.107048
SN - 0584-8547
VL - 221
SP - 1
EP - 8
PB - Elsevier
AN - OPUS4-61339
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Xunyu
A1 - Riedel, Jens
A1 - You, Yi
T1 - Spectrally resolved lithium isotope quantification through high-resolution spatial heterodyne spectrometry
N2 - Isotope ratio determination of lithium is increasingly important in fields ranging from geochemistry to battery diagnostics. While mass spectrometry remains the gold standard, it is costly, cumbersome, and incompatible with portable or inline implementations. Optical emission spectroscopy presents an appealing alternative. However, it is traditionally limited by insufficient spectral resolution or resolving power to separate lithium isotope emissions due to their generalized designs for a wide spectral range; this often requires overly complicated algorithms to overcome the instrumental drawbacks. (79)
Results Here, we report a high-resolution optical method for lithium isotope quantification using a custom-built spatial heterodyne spectrometer (SHS) combined with a reduced-pressure glow discharge source. This configuration yielded a resolving power of 189,000 and enabled baseline resolution of lithium d-line emission features even without the need for preliminary data processing. Despite the inherent low sensitivity of SHS, a detection limit of 30 pmol was achieved using a standard industrial camera. To improve quantitative accuracy, we introduced a deconvolution-based spectral lineshape recovery technique alongside a bootstrapping-based error propagation strategy. These methods facilitated robust isotope ratio calibration using both peak-height and peak-area metrics. The SHS platform additionally enabled the determination of relative transition probabilities, suggesting the feasibility of calibration-free operation.
This work demonstrates the practical viability of SHS for high-specificity, high-resolution lithium isotope analysis. The approach is compact, potentially field-deployable, and adaptable to other elements with optically resolvable isotope shifts, offering a route toward accessible and calibration-free optical isotopic analyses.
KW - SHS
KW - Isotope
KW - High-resolution spectroscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635139
DO - https://doi.org/10.1016/j.aca.2025.344329
SN - 1873-4324
VL - 1368
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohan, M.
A1 - Prochazka, D.
A1 - You, Yi
A1 - Riedel, Jens
A1 - Gornushkin, Igor
A1 - Rocnakova, I.
A1 - Papula, M.
A1 - Porízka, P.
A1 - Kaizer, J.
T1 - Investigating plasma morphology at material boundaries under varying ambient pressures
N2 - Laser-Induced Breakdown Spectroscopy (LIBS) is a widely used technique for elemental analysis. The analysis of the obtained LIBS spectra generally assumes plasma homogeneity. However, using focused laser beams for interrogation, LIBS probes materials on the microscale and is, thus, prone to artefacts from sample heterogeneities on the micrometer scale. An ablation at a material boundary of two matrices may result in a significant inhomogeneity in the plasma plume, which can severely impact the accuracy of quantitative analysis. Since this propagation of the surface morphology into the plasma plume is driven by the plasma expansion, its final impact is strongly pressure dependent. This study examines the influence of varying ambient pressures (7–1000 mbar) on plasma morphology, spectral characteristics, and key plasma properties such as electron number density at a well-defined Cu–Sn boundary, in comparison with the results obtained using homogeneous alloys. Several approaches of plasma imaging with bandpass filters, spectroscopy, and Radon transform-based 3D reconstruction were employed to analyze elemental distribution, signal-to-noise (SNR) and signal-to-background (SBR) ratios, as well as electron number densities. The 3D reconstructions revealed a pronounced plasma asymmetry for the ablation at the material boundary, in contrast to the near-axial symmetry observed for the ablation of homogeneous alloys. At lower pressures, this distinct elemental separation in plasma persisted, while higher pressures led to an increased collisional mixing and homogenization. SNR and SBR were consistently lower for ablation at the boundary compared to homogeneous samples. These findings highlight how boundary ablation contributes to plasma inhomogeneities in LIBS analysis of heterogeneous materials and emphasize the need to account for these
effects when using LIBS for elemental mapping of fine heterogeneous structures.
KW - Laser-induced breakdown spectroscopy
KW - Plasma inhomogeneity
KW - Plasma tomography
KW - Radon transform
KW - Material boundaries
KW - Ambient pressure effects
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634777
DO - https://doi.org/10.1016/j.talanta.2025.128377
SN - 1873-3573
VL - 295
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-63477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Li, Xunyu
A1 - Riedel, Jens
A1 - You, Yi
T1 - Practical high-resolution spectroscopy with a spatial heterodyne spectrometer: Determination of instrumental function for lineshape recovery
N2 - The spatial heterodyne spectrometer (SHS) is a well-recognized platform for its high resolving power in various use cases of spectroscopy. Same as other spectrometer topologies, the SHS, unfortunately, also suffers from classical challenges such as distorted lineshape due to the instrumental function. The goal of this work is to tackle this persisting issue through a simple numerical approach. With the inherent characteristics of an SHS interferogram, we report the direct extraction and determination of the instrumental function in its numerical representation from an SHS interferogram; this instrumental function was further used for spectral data processing that enables significant improvements in spectral resolution through deconvolution algorithms.Here, we systematically discuss the recognition of the embedded instrumental function among various ingredients within an interferogram. To verify the numerical approach, lithium was chosen as the model sample, resembling the use of SHS in an isotopic analysis application. Specifically, the resonance transition of lithium D-lines (2P1/2,3/2 ← 2S1/2) was selected to assess the performance of the spectral processing. With the spectral deconvolution, the spectral features that represent the 6Li and 7Li were nearly baseline-separated, allowing for the accurate measure of the isotopic abundance without external references or algorithm adjustments (e.g., curve fitting).
KW - SHS
KW - Isotopic analysis
KW - High Resolution
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613401
DO - https://doi.org/10.1016/j.sab.2024.107053
SN - 0584-8547
VL - 221
SP - 1
EP - 5
PB - Elsevier
AN - OPUS4-61340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yildirim, Arda
A1 - Sentker, K.
A1 - Smales, Glen Jacob
A1 - Pauw, Brian Richard
A1 - Huber, P.
A1 - Schönhals, Andreas
T1 - Collective orientational order and phase behavior of a discotic liquid crystal under nanoscale confinement
N2 - The phase behavior and molecular ordering of hexakishexyloxy triphenylene (HAT6) DLC under cylindrical nanoconfinement is studied utilizing differential scanning calorimetry (DSC) and dielectric spectroscopy (DS), where cylindrical nanoconfinement is established through embedding HAT6 into the nanopores of anodic aluminum oxide membranes (AAO), and a silica membrane with pore diameters ranging from 161 nm down to 12 nm. Both unmodified and modified pore walls were considered, and in the latter case the pore walls of AAO membranes were chemical treated with n octadecylphosphonic acid (ODPA) resulting in the formation of a 2.2 nm thick layer of grafted alkyl chains. Phase transition enthalpies decrease with decreasing pore size, indicating that a large proportion of the HAT6 molecules within the pores has a disordered structure, which increases with decreasing pore size for both pore walls. In the case of the ODPA modification the amount of ordered HAT6 is increased compared to the unmodified case. The pore size dependencies of the phase transition temperatures were approximated using the Gibbs Thomson equation, where the estimated surface tension is dependent on the molecular ordering of HAT6 molecules within the pores and upon their surface. DS was employed to investigate the molecular ordering of HAT6 within the nanopores. These investigations revealed that with a pore size of around 38 nm, for the samples with the unmodified pore walls, the molecular ordering changes from planar axial to homeotropic radial. However, the planar axial configuration, which is suitable for electronic applications, can be successfully preserved through ODPA modification for most of the pore sizes.
KW - Discotic Liquid Crystals
KW - Nanoconfinement
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475222
DO - https://doi.org/10.1039/c8na00308d
SN - 2516-0230
VL - 1
IS - 3
SP - 1104
EP - 1116
PB - RSC
AN - OPUS4-47522
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Michalik-Onichimowska, Aleksandra
A1 - Kern, Simon
A1 - Riedel, Jens
A1 - Panne, Ulrich
A1 - King, R.
A1 - Maiwald, Michael
T1 - ‘‘Click” analytics for ‘‘click” chemistry – A simple method for calibration–free evaluation of online NMR spectra
N2 - Driven mostly by the search for chemical syntheses under biocompatible conditions, so called "click" chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of 1H spectra with a time interval of 20 s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibrationfree approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9 h-1 at 25 °C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance.
KW - Online NMR Spectroscopy
KW - Reaction Monitoring
KW - Automated Data Evaluation
KW - Thiol-ene click chemistry
KW - Click Chemistry
KW - Process Analytical Technology
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393232
UR - http://www.sciencedirect.com/science/article/pii/S1090780717300575
DO - https://doi.org/10.1016/j.jmr.2017.02.018
VL - 277
SP - 154
EP - 161
PB - Elsevier Inc.
CY - Oxford
AN - OPUS4-39323
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Jungnickel, Robert
A1 - Dariz, P.
T1 - Insights into the CaSO4–H2O System: A Raman-Spectroscopic Study
N2 - Even though being the subject of natural scientific research for many decades, the system CaSO4–H2O, consisting of the five crystalline phases gypsum, bassanite, and the anhydrites III, II, and I, has left many open questions for research. Raman spectroscopy was used because of its structural sensitivity and in situ measurement capability to obtain further insight by studying phase transitions in both ex situ and in situ experiments. The findings include significant contributions to the completeness and understanding of Raman spectroscopic data of the system. The dehydration path gypsum–bassanite–anhydrite III was shown to have strong parallels to a physical drying process, which depends on many parameters beyond the burning temperature. Raman band width determination was demonstrated to enable the quantitative discrimination of α-bassanite and β-bassanite as well as the postulated three sub-forms of anhydrite II (AII), which are all based on differences in crystallinity. In the latter case, the observed continuous structural variations over increasing burning temperatures were elucidated as a combination of decreasing surface areas and healing of crystal lattice defects. We propose an only two-fold sub-division of AII into reactive “disordered AII” and much less reactive “crystalline AII” with a transition temperature of 650°C ± 50 K.
KW - Gypsum
KW - Bassanite
KW - Hemihydrate
KW - Anhydrite
KW - Raman spectroscopy
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506701
DO - https://doi.org/10.3390/min10020115
SN - 2075-163X
VL - 10
IS - 2
SP - 115, 35
PB - MDPI
CY - Basel
AN - OPUS4-50670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Dariz, P.
T1 - Raman Microspectroscopic Imaging of Binder Remnants in Historical Mortars Reveals Processing Conditions
N2 - Binder remnants in historical mortars represent a record of the connection between the raw materials that enter the kiln, the process parameters, and the end product of the calcination. Raman microspectroscopy combines high structural sensitivity with micrometre to sub-micrometre spatial resolution and compatibility with conventional thin-sectional samples in an almost unique fashion, making it an interesting complementary extension of the existing methodological arsenal for mortar analysis. Raman spectra are vibrational fingerprints of crystalline and amorphous compounds, and contain marker bands that are specific for minerals and their polymorphic forms. Relative intensities of bands that are related to the same crystalline species change according to crystal orientations, and band shifts can be caused by the incorporation of foreign ions into crystal lattices, as well as stoichiometric changes within solid solution series. Finally, variations in crystallinity affect band widths. These effects are demonstrated based on the analysis of three historical mortar samples: micrometric distribution maps of phases and polymorphs, crystal orientations, and compositional variations of solid solution series of unreacted clinker grains in the Portland cement mortars of two 19th century castings, and the crystallinities of thermal anhydrite clusters in a high-fired medieval gypsum mortar as a measure for the applied burning temperature were successfully acquired.
KW - Cement clinker remnants
KW - High-fired gypsum
KW - Thermal anhydrite
KW - Spectroscopic imaging
KW - Raman microscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515038
DO - https://doi.org/10.3390/heritage2020102
VL - 2
IS - 2
SP - 1662
EP - 1683
PB - MDPI
CY - Basel
AN - OPUS4-51503
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Riedel, Jens
T1 - Approaching phase-imaging through defocusing shadowgraphy for acoustic resonator diagnosis and the capability of direct index-of-refraction measurements
N2 - The visualization of index-of-refraction (IoR) distribution is one of the common methods to investigate fluid flow or pressure fields. While schlieren and shadowgraphy imaging techniques are widely accepted, their inherent limitations often lead to difficulties in elucidating the IoR distribution and extracting the true IoR information from the resulting images. While sophisticated solutions exist, the IoR-gradient-to-image was achieved by purposely introducing a commonly avoided “defect” into the optical path of a conventional coincident schlieren/shadowgraphy setup; the defect is a combination of slight defocusing and the use of non-conjugate optical components. As such, the method presented in this work is referred to as defocusing shadowgraphy, or DF-shadowgraphy. While retaining the ease of a conventional schlieren/shadowgraphy geometry, this DF approach allows direct visualization of complicated resonant acoustic fields even without any data processing. For instance, the transient acoustic fields of a common linear acoustic resonator and a two-dimensional one were directly visualized without inversion. Moreover, the optical process involved in DF-shadowgraphy was investigated from a theoretical perspective. A numerical solution of the sophisticated impulse response function was obtained, which converts the phase distortion into intensity distributions. Based on this solution, the IoRs of various gas streams (e.g., CO2 and isopropanol vapor) were determined from single images.
KW - Imaging Technique
KW - Phase Imaging
KW - Shadowgraphy
KW - Schlieren Imaging
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537116
DO - https://doi.org/10.1063/5.0058334
SN - 1089-7623
VL - 92
IS - 10
SP - 103703
PB - AIP Publishing Group
AN - OPUS4-53711
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silbernagl, Dorothee
A1 - Ghasem Zadeh Khorasani, Media
A1 - Cano Murillo, Natalia
A1 - Elert, Anna Maria
A1 - Sturm, Heinz
ED - Glatzel, T.
T1 - Bulk chemical composition contrast from attractive forces in AFM force spectroscopy
N2 - A key application of atomic force microscopy (AFM) is the measurement of physical properties at sub-micrometer resolution. Methods such as force–distance curves (FDCs) or dynamic variants (such as intermodulation AFM (ImAFM)) are able to measure mechanical properties (such as the local stiffness, kr) of nanoscopic heterogeneous materials. For a complete structure–property correlation, these mechanical measurements are considered to lack the ability to identify the chemical structure of the materials. In this study, the measured attractive force, Fattr, acting between the AFM tip and the sample is shown to be an independent measurement for the local chemical composition and hence a complete structure–property correlation can be obtained. A proof of concept is provided by two model samples comprised of (1) epoxy/polycarbonate and (2) epoxy/boehmite. The preparation of the model samples allowed for the assignment of material phases based on AFM topography. Additional chemical characterization on the nanoscale is performed by an AFM/infrared-spectroscopy hybrid method. Mechanical properties (kr) and attractive forces (Fattr) are calculated and a structure–property correlation is obtained by a manual principle component analysis (mPCA) from a kr/Fattr diagram. A third sample comprised of (3) epoxy/polycarbonate/boehmite is measured by ImAFM. The measurement of a 2 × 2 µm cross section yields 128 × 128 force curves which are successfully evaluated by a kr/Fattr diagram and the nanoscopic heterogeneity of the sample is determined.
KW - AFM force spectroscopy
KW - Composites
KW - Principle component analysis
KW - Structure–property correlation
KW - Van der Waals forces
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520175
DO - https://doi.org/10.3762/bjnano.12.5
SN - 2190-4286
VL - 12
IS - 5
SP - 58
EP - 71
PB - Beilstein Institute
CY - Frankfurt am Main
AN - OPUS4-52017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mezera, Marek
A1 - Alamri, S.
A1 - Hendriks, W. A. P. M.
A1 - Hertwig, Andreas
A1 - Elert, Anna Maria
A1 - Bonse, Jörn
A1 - Kunze, T.
A1 - Lasagni, A. F.
A1 - Römer, G. R. B. E.
T1 - Hierarchical micro-/nano-structures on polycarbonate via UV pulsed laser processing
N2 - Hierarchical micro/-nanostructures were produced on polycarbonate polymer surfaces by employing a two-step UV-laser processing strategy based on the combination of Direct Laser Interference Patterning (DLIP) of gratings and pillars on the microscale (3 ns, 266 nm, 2 kHz) and subsequently superimposing Laser-induced Periodic Surface Structures (LIPSS; 7–10 ps, 350 nm, 100 kHz) which adds nanoscale surface features. Particular emphasis was laid on the influence of the direction of the laser beam polarization on the morphology of resulting hierarchical surfaces. Scanning electron and atomic force microscopy methods were used for the characterization of the hybrid surface structures. Finite-difference time-domain (FDTD) calculations of the laser intensity distribution on the DLIP structures allowed to address the specific polarization dependence of the LIPSS formation observed in the second processing step. Complementary chemical analyzes by micro-Raman spectroscopy and attenuated total reflection Fourier-transform infrared spectroscopy provided in-depth information on the chemical and structural material modifications and material degradation imposed by the laser processing. It was found that when the linear laser polarization was set perpendicular to the DLIP ridges, LIPSS could be formed on top of various DLIP structures. FDTD calculations showed enhanced optical intensity at the topographic maxima, which can explain the dependency of the morphology of LIPSS on the polarization with respect to the orientation of the DLIP structures. It was also found that the degradation of the polymer was enhanced for increasing accumulated fluence levels.
KW - Direct laser interference patterning
KW - Laser-induced periodic surface structures (LIPSS)
KW - Polycarbonate
KW - Hierarchical structures
KW - Surface functionalization
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509101
DO - https://doi.org/10.3390/nano10061184
SN - 2079-4991
VL - 10(6)
IS - Special issue "Laser-generated periodic nanostructures"
SP - 1184-1
EP - 1184-19
PB - MDPI
CY - Basel
AN - OPUS4-50910
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Kraft, Ronja
A1 - Dariz, P.
T1 - Shedding light onto the spectra of lime - Part 2: Raman spectra of Ca and Mg carbonates and the role of d-block element luminescence
N2 - We previously described the observation of a characteristic narrowband red luminescence emission of burnt lime (CaO), whose reason was unknown so far. This study presents Raman spectra of Mg5 CO3)4(OH)2∙4H2O, Mg5(CO3)4(OH)2, MgCO3, CaMgCO3 and CaCO3 (in limestone powder) as well as luminescence spectra of their calcination products. Comparison of the latter revealed MgO:Cr3+ as the source of the red lime luminescence in all studied samples, containing magnesium oxide as major component, minor component or trace. Spectral characteristics and theoretical background of the luminescence emission of d-block elements integrated in crystal lattices are discussed with the aim of sharpening the awareness for this effect in the Raman community and promoting its application in materials analysis. The latter is demonstrated by the Raman microspectroscopic imaging of the distributions of both Raman-active and Raman-inactive phases in clinker remnants in a 19th-century meso Portland cement mortar sample, which contain relatively high amounts of free lime detected in the form of both luminescing CaO and Raman-scattering Ca(OH)2, owing to exposure of the surface of the thin section to humid air. A combination of light and Raman spectroscopy revealed a calcium–magnesium–iron sulphide phase, indicating sulphurous raw materials and/or solid fuels employed in the calcination process, which in contrast to previously described morphologies of sulphides in cement clinker form extensive greenish black layers on free lime crystals.
KW - Calcium carbonates
KW - Raman spectroscopy
KW - Luminescence
KW - Magnesium carbonates
KW - Meso Portland cement
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537611
DO - https://doi.org/10.1002/jrs.6174
SN - 0377-0486
VL - 52
IS - 8
SP - 1462
EP - 1472
PB - Wiley Analytical Science
AN - OPUS4-53761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmid, Thomas
A1 - Dariz, P.
T1 - Editorial for the special issue "Modern Raman spectroscopy of minerals"
N2 - Raman spectroscopy provides vibrational fingerprints of chemical compounds enabling their unambiguous identification. The assignment of Raman spectra to minerals is straightforward, if appropriate reference data is accessible. Modern couplings of Raman spectroscopy with microscopy (Raman microspectroscopy) merge the high structural specificity with down to sub-micrometre spatial resolution. This analytical tool has high potential not only in the identification of minerals from natural sources but also for studying the complex microstructure and mineral distribution of both ancient and modern man-made materials. In addition to the chemical identity of minerals, Raman spectra are affected by crystal orientations (varying relative Raman band intensities); (sub)stoichiometric compositional changes (e.g., in solid solution series), traces of foreign ions, strain (the latter three shifting Raman bands); and crystallinity (changing Raman band widths), enabling a comprehensive physico-chemical characterisation of minerals. Thus, Raman spectroscopy – including its in situ measurement capabilities – provides possibilities to study mineral paragenesis in both, natural and man-made samples at the micrometre scale. While in 1928 the first experimental evidence for inelastic light scattering was provided by C. V. Raman and K. S. Krishnan by using sunlight for excitation, filters for selecting the inelastically scattered light, and their eyes for detection (later, photographic plates for acquisition of spectra were employed), modern Raman spectrometers make use of laser excitation, dispersive spectrographs and charge coupled device (CCD) detection. This Special Issue includes technological developments and applications in the field of modern Raman spectroscopy of minerals in a broad sense, from natural mineral deposits and archaeological objects to inorganic phases in man-made materials. The studied minerals include fossil resins, typical rock-forming minerals (calcite, quartz, forsterite), iron-sulphur species (e.g., mackinawite), a range of sulphates (gypsum, bassanite, anhydrite III, anhydrite II, celestine, barite, ternesite), as well as silicate minerals like garnets (e.g., almandine).
KW - Raman spectroscopy
KW - Raman microspectroscopy
KW - Mineral identification
KW - Physico-chemical characterisation of minerals
KW - Mineral paragenesis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515041
DO - https://doi.org/10.3390/min10100860
VL - 10
SP - 860
PB - MDPI
CY - Basel
AN - OPUS4-51504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Denkler, Tilman
T1 - Accreditation in Europe: Benchmarking the operations of European accreditation bodies using an innovative management tool
N2 - Accreditation is one of the pillars of a national Quality Infrastructure, as the competence of conformity assessment bodies is assured through accreditation performed by accreditation bodies. To compare the operation of accreditation bodies in Europe and to identify best practices, a management tool, the Process Maturity Benchmarking Tool, was developed and validated by applying it to European accreditation bodies. The benchmarking project comprised two major phases: In the first phase, the processes of accreditation bodies were systematically analyzed. A process map was developed, and processes of special relevance were identified and underpinned by indicators. In the second phase, the practical applicability of the theoretical model was demonstrated by analyzing the processes of eight European accreditation bodies. The results of this comparative assessment were subsequently discussed in a workshop with experts from those accreditation bodies, giving the opportunity to identify best practices.
This article has a twofold objective. First, to present a method to benchmark European accreditation bodies, based on the European Foundation for Quality Management excellence model. The successful application of the Process Maturity Benchmarking Tool gives evidence that it is a suitable and capable management tool to assess the processes of the European accreditation bodies and to benchmark them. Second, the article presents the results of the first adaption of the Process Maturity Benchmarking Tool. A general trend of process maturity was identified: While processes based on stakeholder involvement tend to have an overall lower maturity on average, internal processes are more mature.
KW - Accreditation
KW - Benchmarking
KW - Quality Infrastructure
KW - EFQM Excellence Modell
KW - Total Quality Management
KW - Akkreditierung
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521706
DO - https://doi.org/10.1007/s00769-021-01459-7
VL - 26
IS - 1
SP - 47
EP - 57
PB - Springer Nature
CY - Jersey City, NJ 07302, USA
AN - OPUS4-52170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhattacharya, Biswajit
A1 - Michalchuk, Adam
A1 - Silbernagl, Dorothee
A1 - Rautenberg, Max
A1 - Schmid, Thomas
A1 - Feiler, Torvid
A1 - Reimann, K.
A1 - Ghalgaoui, A.
A1 - Sturm, Heinz
A1 - Paulus, B.
A1 - Emmerling, Franziska
T1 - A Mechanistic Perspective on Plastically Flexible Coordination Polymers
N2 - Mechanical flexibility in single crystals of covalently bound materials is a fascinating and poorly understood phenomenon. We present here the first example of a plastically flexible one-dimensional (1D) coordination polymer. The compound [Zn(m-Cl)2(3,5-dichloropyridine)2]n is flexible over two crystallographic faces. Remarkably, the single crystal remains intact when bent to 1808. A combination of microscopy, diffraction, and spectroscopic studies have been used to probe the structural response of the crystal lattice to mechanical bending. Deformation of the covalent polymer chains does not appear to be responsible for the observed macroscopic bending. Instead, our results suggest that mechanical bending occurs by displacement of the coordination polymer chains. Based on experimental and theoretical evidence, we propose a new model for mechanical flexibility in 1D coordination polymers. Moreover, our calculations propose a cause of the different mechanical properties of this compound and a structurally similar elastic material
KW - Coordination polymer
KW - Flexible crystals
KW - Mechanical properties
KW - Plastic deformation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504755
DO - https://doi.org/10.1002/anie.201914798
VL - 59
IS - 14
SP - 5557
EP - 5561
PB - Wiley-VCH
AN - OPUS4-50475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghasem Zadeh Khorasani, Media
A1 - Elert, Anna Maria
A1 - Hodoroaba, Vasile-Dan
A1 - Agudo Jácome, Leonardo
A1 - Altmann, Korinna
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
T1 - Short- and long-range mechanical and chemical interphases caused by interaction of Boehmite (γ-AlOOH) with anhydride-cured epoxy resins
N2 - Understanding the interaction between boehmite and epoxy and the formation of their interphases with different mechanical and chemical structures is crucial to predict and optimize the properties of epoxy-boehmite nanocomposites. Probing the interfacial properties with atomic force microscopy (AFM)-based methods, especially particle-matrix long-range interactions, is challenging. This is due to size limitations of various analytical methods in resolving nanoparticles and their interphases, the overlap of interphases, and the effect of buried particles that prevent the accurate interphase property measurement. Here, we develop a layered model system in which the epoxy is cured in contact with a thin layer of hydrothermally synthesized boehmite. Different microscopy methods are employed to evaluate the interfacial properties. With intermodulation atomic force microscopy (ImAFM) and amplitude dependence force spectroscopy (ADFS), which contain information about stiffness, electrostatic, and van der Waals forces, a soft interphase was detected between the epoxy and boehmite. Surface potential maps obtained by scanning Kelvin probe microscopy (SKPM) revealed another interphase about one order of magnitude larger than the mechanical interphase. The AFM-infrared spectroscopy (AFM-IR) technique reveals that the soft interphase consists of unreacted curing agent. The long-range electrical interphase is attributed to the chemical alteration of the bulk epoxy and the formation of new absorption bands.
KW - Nanocomposites
KW - Interphase
KW - Intermodulation AFM
KW - Electron microscopy
KW - Infrared nano AFM
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-483672
UR - https://www.mdpi.com/2079-4991/9/6/853/htm
DO - https://doi.org/10.3390/nano9060853
SN - 2079-4991
VL - 9
IS - 6
SP - 853, 1
EP - 20
PB - MDPI
AN - OPUS4-48367
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Xue, Boyang
A1 - Riedel, Jens
T1 - Enhancement of LIBS plasma in air with organic solvent vapors
N2 - Laser-induced breakdown spectroscopy (LIBS) offers versatile, field-deployable elemental analysis; however, compact, high-repetition-rate nanosecond laser systems typically face constraints in power consumption and size, often compromising emission intensity and thus analytical performance. We demonstrate a significant improvement in LIBS signals through the controlled introduction of common organic solvent vapors into a sheath gas, with a diode-pumped solid-state laser (1064 nm, 2–28 kHz repetition rate, 450–600-μJ pulse energy). Optical and acoustic diagnostics reveal up to ca. 40-fold enhancement of the N II emission line at 567 nm when ambient air serves as the analyte. Maximal enhancement occurs at intermediate repetition rates of ca. 15 kHz, particularly at pulse energies approaching the optical breakdown threshold; this observation suggests a viable strategy for operating LIBS at lower pulse energies and higher repetition rates. Enhancement effects scale jointly with both vapor pressure and ionization energy of the organic species, with acetone and toluene markedly outperforming methanol and isopropanol. These findings provide a rational foundation for significantly improving the analytical performance of portable LIBS instruments without exceeding platform-specific constraints.
KW - LIBS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653758
DO - https://doi.org/10.1016/j.sab.2025.107309
SN - 0584-8547
VL - 236
SP - 1
EP - 6
PB - Elsevier B.V.
AN - OPUS4-65375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raab, A. R.
A1 - Grießler, T. R.
A1 - Rück, D.
A1 - Li, Z.
A1 - Zens, A.
A1 - Bruckner, J. R.
A1 - Huber, P.
A1 - Schönhals, Andreas
A1 - Szymoniak, Paulina
A1 - Laschat, S.
T1 - Salt complexation drives liquid crystalline selfassembly in crown ether–amino acid hybrids
N2 - Crown ether–amino acid hybrids represent a promising class of amphiphilic molecules combining ion recognition with self-assembly capabilities. Despite extensive studies on their binding properties, the influence of inorganic salt complexation on their liquid crystalline behaviour remains underexplored. Here we synthesized amphiphilic [18]-crown-6 derivatives of L-dihydroxyphenylalanine and tetrahydroisoquinoline analogues, systematically investigating the effects of alkyl chain length and salt type on mesophase formation. Complexation with various salts induced liquid crystalline phases, transitioning from smectic A to columnar hexagonal structures as anion size and alkyl chain length increased.
Structural analyses and electron density mapping revealed assembly into charged superdiscs forming columnar stacks with tunable ion channels. Broadband dielectric spectroscopy highlighted differences in molecular mobility and conductivity linked to molecular design. These findings establish salt complexation as a key strategy to control self-assembly and ion transport in crown ether–amino acid hybrids, advancing their potential in responsive soft materials and ion-conductive applications.
KW - Ionic liquid crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655986
DO - https://doi.org/10.1039/d5tc04129e
SP - 1
EP - 18
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kolmangadi, Mohamed A.
A1 - Raab, A. R.
A1 - Szymoniak, Paulina
A1 - Li, Z.
A1 - Huber, P.
A1 - Laschat, S.
A1 - Schönhals, Andreas
T1 - Molecular mobility and electrical conductivity of amino acid-based (DOPA) ionic liquid crystals in the bulk state and nanoconfinement
N2 - This study explores the molecular mobility, phase behavior, and electrical conductivity of dihydroxyphenylalanine-based ionic liquid crystals (DOPAn, with alkyl side chains n = 12, 14, 16) featuring cyclic guanidiniumchloride headgroups, in both bulk and nanoconfined states. Using broadband dielectric spectroscopy, differential scanning calorimetry, and fast scanning calorimetry, the research uncovers a complex interplay between molecular structure, self-assembly, and molecular mobility. In bulk, DOPAn shows a phase sequence from plastic crystalline to hexagonal columnar and isotropic phases, driven by superdisc formation and columnar organization. Multiple relaxation processes are identified: localized side-chain dynamics (γ-relaxation), ionic headgroup or core motions (α1-relaxation), and cooperative alkyl domain fluctuations (α2-relaxation). Conductivity decreases with increasing side chain length. Under nanoconfinement in anodic aluminum oxide membranes, phase behavior changes: the Colh–Iso transition is suppressed, and a new α3-relaxation appears, linked to dynamics in an adsorbed interfacial layer. DC conductivity drops by up to four orders of magnitude due to confinement effects, altered molecular orientation, and phase transitions—especially the emergence of a nematic-like state in DOPA16. These findings highlight the importance of molecular design, pore geometry, and surface chemistry in tuning ionic liquid crystal properties for advanced applications in nanofluidics, ion transport, and responsive materials.
KW - Ionic Liquid Crystals
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639657
DO - https://doi.org/10.1039/d5cp02406d
SN - 1463-9084
SP - 1
EP - 17
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63965
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Abbassi, Abdelouahad
A1 - Fürstenwerth, Paul
A1 - Würth, Christian
A1 - Tavernaro, Isabella
A1 - Resch-Genger, Ute
T1 - Validated workflows for preparing and characterizing core-stained and surface-labeled fluorescent polymer particles with simple commercial automation tools
N2 - Preparation workflows of fluorescent nm- and µm-sized polymer particles used as reporters in fluorescent assays, bioimaging, and sensing studies or calibration tools for fluorescence methods in the life sciences can be time-consuming and labor-intensive. Also, the outcome can be operator dependent. Here, we present simple and cost-efficient automated workflows for dye loading and surface labeling of polystyrene particles (PSP), using a commercial self-programmable pipetting robot. For developing and fine-tuning automated staining workflows, hydrophobic Nile Red (NR) was incorporated into 100 nm, 200 nm, and 1000 nm PSP by an adapted swelling procedure of premanufactured particles in the presence of hydrophobic dyes, thereby confirming its reliability and versatility. Subsequent expansion of our automation concept to the labeling of carboxylated PSP with pH-sensitive 6-aminofluorescein (6-AMF) and aminated PSP with pH-responsive fluorescein isocyanate (FITC) demonstrated its broad applicability. All automated workflows were optimized and validated by gravimetry and spectroscopic measurements with a microtiter plate (MTP) reader in absorption and fluorescence mode to ensure particle recovery and reproducible fluorescence features and determine PSP dye loading and labeling efficiencies. Comparison with the manual fabrication of NR-stained PSP using an established swelling protocol showed that our automation approach utilizing a pipetting robot considerably reduced the variability in particle recovery and dye loading efficiency. Overall, our simple, labor- and time-efficient workflows with inexpensive and broadly available commercial automation tools present attractive alternatives to manual particle loading and labeling and provide the basis for fast parameter screening, parallel processing, and decreased hands-on time.
KW - Automation
KW - Fluorescent polymer beads
KW - Dye staining
KW - Fluorescent labeling
KW - Nanomaterials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658451
DO - https://doi.org/10.1007/s00216-026-06443-z
SN - 1618-2642
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-65845
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hernández García, María Amparo
A1 - Rurack, Knut
A1 - Bell, Jérémy
T1 - Rapid fabrication of optical elements for sensing applications using a standard SLA printer
N2 - The demand for compact, high-performance optical components has driven the development of increasingly sophisticated and miniaturized optical elements, often requiring complex and costly fabrication methods. In this work, we propose a cost-effective and accessible methodology for the fabrication of lenses and free-form optics using a commercially available stereolithography (SLA) 3D printer. A systematic characterization of six transparent photopolymer resins was conducted in terms of their spectroscopic, optical, and morphological properties, i.e., surface and dimensional properties. The evaluation encompassed parameters such as transmittance, autofluorescence, refractive index, and surface roughness. A straightforward and robust printing and posttreatment protocol was developed, facilitating the fabrication of optical components with over 80% transmittance, minimal intrinsic fluorescence, and a surface quality that is compatible with demanding optical applications. The fabricated components demonstrated excellent dimensional fidelity to digital designs and high reproducibility. To demonstrate the versatility of this approach, aspherical, miniaturized, and free-form lenses were designed and integrated into three fluorescence sensing systems, including oil (strip based) and chlorine (microfluidic based) detection platforms, as well as a smartphone-based SARSCoV-2 biosensor. The integration of customized 3Dprinted optics has been shown to improve signal collection and readout performance, thereby highlighting the potential of this approach for broad application by a wide range of user groups in rapid prototyping and use in miniaturized optical systems. This work represents a significant advancement in the field of additive manufacturing, particularly in relation to the development of functional photonic devices. Furthermore, it opens new prospects for sensor applications in biosensing, microfluidics, imaging, and integrated optics.
KW - 3D-printing
KW - Free-form
KW - Prototyping
KW - Optical resin
KW - Surface-finishing
KW - Fluorescence
KW - Sensor
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655558
DO - https://doi.org/10.37188/lam.2026.024
SN - 2689-9620
VL - 7
SP - 1
EP - 12
PB - Light Publishing Group
CY - Foshan City
AN - OPUS4-65555
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mekonnen, Tessema Fenta
A1 - Panne, Ulrich
A1 - Koch, Matthias
T1 - New photodegradation products of the fungicide fluopyram: Structural elucidation and mechanism identification
N2 - Identifying the fate of agrochemicals is important to understand their potential risk for living organisms. We report here new photodegradation products (PPs) of the fungicide fluopyram. The PPs were produced by irradiating a fluopyram standard in 0.1% acetonitrile aqueous media by a 150-W medium pressure Hg-lamp that emits wavelengths between 200–280 nm. The structural elucidation of PPs was achieved by combining the retention time, isotopic pattern, targeted fragmentation, and accurate mass measurements using liquid chromatography-tandem mass spectrometry (LC-MS/MS) and high resolution-MS (HRMS). In addition to previously known PPs, seven new PPs of fluopyram were identified in this work: mainly dihydroxyl and hydroxylimide fluopyram as well as mono, di, and trihydroxyl lactam. Additionally, two PPs were found to be formed by rearrangement after the loss of H2C=CH2. Hence, the results of the work contribute to extending the current knowledge regarding the photoinduced fate of agrochemicals, and fluopyram in particular.
KW - Photodegradation
KW - Transformation products
KW - LC-MS/MS
KW - HRMS
KW - Fungicide
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-466347
DO - https://doi.org/10.3390/molecules23112940
SN - 1420-3049
VL - 23
IS - 11
SP - 2940, 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-46634
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sötebier, Carina A.
A1 - Kutscher, D. J.
A1 - Rottmann, L.
A1 - Jakubowski, Norbert
A1 - Panne, Ulrich
A1 - Bettmer, J.
T1 - Combination of single particle ICP-QMS and isotope dilution analysis for the determination of size, particle number and number size distribution of silver nanoparticles
N2 - Single particle ICP-MS (spICP-MS) has gained great influence in the analysis of engineered nanoparticles (NPs) due to its simplicity, speed and ability to obtain a particle number size distribution. Despite its many advantages, the method is hampered by matrix effects affecting the sensitivity of the instruments.
Consequently, over- or underestimated particle sizes might be obtained. To overcome these challenges, we present in this work the detection of both Ag isotopes with a quadrupole mass spectrometer for the application of isotopic dilution analysis (IDA) in combination with spICP-MS. Here, the isotopes are measured sequentially using the conventional spICP-MS integration time of 10 ms. Citrate stabilized Ag NPs of a spherical shape with the nominal diameters of 30, 40, 50 and 80 nm have been investigated.
The experimental concept of adding ¹⁰⁹Ag+ solutions to the NP suspensions resulted in the NP Spikes being only visible in the ¹⁰⁷Ag trace. Therefore, a maximum of 45% of the particles was detected compared to that by conventional spICP-MS. A modified mass flow equation was applied to determine the particle sizes, particle size distributions and particle number concentrations of various Ag NPs. The addition of different spike concentrations between 0.5 and 4 mg L⁻¹ ¹⁰⁹Ag resulted in similar particle diameters, suggesting that the calculated diameter might be independent of the spike concentration.
This would have the advantage that no size information would be needed before the analysis. By analyzing Ag NP suspensions in a simulated seawater matrix, we demonstrate its significant influence on the particle size determination using conventional spICP-MS. A lower transport efficiency of 6.1% was found in the matrix compared to 7.3% without the matrix. In our approach, the addition of the Matrix influenced the NP intensity stronger than the spike signal, resulting in slightly smaller diameters using IDA–spICP-MS with the matrix compared to the results without the matrix. On the other hand, the IDA–spICP-MS approach with the matrix can result in equivalent results for the particle sizes compared with
conventional spICP-MS using suspensions without the matrix. Due to the lower instrument sensitivity in the matrix, a diameter of 30 nm was found to be close to the detection limit of the instrument.
KW - Ag nanoparticles
KW - Single particle ICP-MS
KW - Matrix influence
KW - Isotope dilution analysis
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376490
DO - https://doi.org/10.1039/c6ja00137h
SN - 0267-9477
VL - 31
IS - 10
SP - 2045
EP - 2052
AN - OPUS4-37649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bolz, Axel
A1 - Panne, Ulrich
A1 - Rurack, Knut
A1 - Buurman, Merwe
T1 - Glass fibre paper-based test strips for sensitive SERS sensing
N2 - We present paper-based test strips for chemical sensing with surface enhanced Raman scattering as detection method. The test strips are prepared on glass fibre paper with silver nanoparticles and a spray method with an airbrush spray setup as a low cost fabrication approach. The properties of the test strips are investigated with three classical Raman analytes rhodamine 6G, 4-aminothiophenol and adenine and optimized for a good reproducibility of the intensity measurements. All test analytes can be identified at low concentrations. For adenine, a concentration series from 10⁻⁴ M to 10⁻⁸ M is measured and the calibration data can be fitted and evaluated with a Langmuir isotherm model. The optimized test strips are applied for the identification of two antibiotics enoxacin and enrofloxacin.
KW - surface enhanced Raman scattering
KW - glass fibre paper
KW - sensing
KW - spray
KW - Langmuir isotherm
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-354878
DO - https://doi.org/10.1039/C5AY03096J
SN - 1759-9660
VL - 8
IS - 6
SP - 1313
EP - 1318
PB - The Royal Society of Chemistry
AN - OPUS4-35487
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachenberger, Yves Uwe
A1 - Krause, Benjamin Christoph
A1 - Kriegel, Fabian Lukas
A1 - Reichardt, Philipp
A1 - Tentschert, Jutta
A1 - Jungnickel, Harald
A1 - Bierkandt, Frank Stefan
A1 - Laux, Peter
A1 - Panne, Ulrich
A1 - Luch, Andreas
T1 - Developing a multi-method approach for understanding cellular uptake and biological response: Investigating co-exposure of macrophage-like differentiated THP-1 cells to Al2O3 and CeO2 nanoparticles
N2 - The use of different nanoparticles (NPs) is increasing in a wide variety of everyday products. Nevertheless, most studies concerning NP risk assessment have evaluated exposure scenarios involving a single kind of NP. A stepwise study distinguishing between the effects resulting from exposure to one kind of NP and those resulting from different co-exposure scenarios to Al2O3 and CeO2 NPs at concentrations below acute toxicity was conducted with different analytical techniques. As a starting point, WST-1 viability assays were performed to assess whether the chosen exposure concentrations resulted in any acute loss of viability, which would hamper further insight into the cellular response to NP exposure. Then, data on NP dissolution and uptake were obtained via single-particle inductively coupled plasma–mass spectrometry (spICP-MS) and microwave-assisted ICP-MS. Additionally, time-of-flight secondary ion mass spectrometry (ToF-SIMS) was performed to check for differences in the biological response to the exposure scenarios at the single-cell level. It was found that the proposed combined techniques provide insight into changes in biological responses as well as cellular metal contents among the exposure scenarios. In this work, a comprehensive tiered analytical strategy for evaluating the biological responses to challenging exposure scenarios is provided. The results highlight the necessity of selecting situations more closely resembling real life—including concentrations below acute toxicity and potential interactions due to multiple NPs—when estimating potential health risks. These findings thus provide a foundation and an incentive for further research into the complex processes leading to the observed effects.
KW - Nano
KW - Co-exposition
KW - Viability changes
KW - ICP-MS
KW - ToF-SIMS
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657732
DO - https://doi.org/10.3390/molecules30071647
SN - 1420-3049
VL - 30
IS - 7
SP - 1
EP - 17
PB - MDPI
CY - Basel
AN - OPUS4-65773
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mekonnen, Tessema Fenta
A1 - Panne, Ulrich
A1 - Koch, Matthias
T1 - Glucosylation and Glutathione Conjugation of Chlorpyrifos and Fluopyram Metabolites Using Electrochemistry/Mass Spectrometry
N2 - Xenobiotics and their reactive metabolites are conjugated with native biomolecules such as glutathione and glucoside during phase II metabolism. Toxic metabolites are usually detoxified during this step. On the other hand, these reactive species have a potential health impact by disrupting many enzymatic functions. Thus, it is crucial to understand phase II conjugation reactions of xenobiotics in order to address their fate and possible toxicity mechanisms.
Additionally, conventional methods (in vivo and in vitro) have limitation due to matrix complexity and time-consuming. Hence, developing fast and matrix-free alternative method is highly demandable. In this work, oxidative phase I metabolites and reactive species of chlorpyrifos (insecticide) and fluopyram (fungicide) were electrochemically produced by using a boron-doped diamond electrode coupled online to electrospray mass spectrometry (ESI-MS). Reactive species of the substrates were trapped by biomolecules (glutathione and glucoside) and phase II conjugative metabolites were identified using liquid chromatography (LC)-MS/MS, and/or Triple time of flight (TripleTOF)-MS. Glutathione conjugates and glucosylation of chlorpyrifos, trichloropyridinol, oxon, and monohydroxyl fluopyram were identified successfully. Glutathione and glucoside were conjugated with chlorpyrifos, trichloropyridinol, and oxon by losing a neutral HCl. In the case of fluopyram, its monohydroxyl metabolite was actively conjugated with both glutathione and glucoside. In summary, seven bioconjugates of CPF and its metabolites and two bioconjugates of fluopyram metabolites were identified using electrochemistry (EC)/MS for the first time in this work. The work could be used as an alternative approach to identify glutathione and glucosylation conjugation reactions of other organic compounds too. It is important, especially to predict phase II conjugation within a short time and matrix-free environment.
KW - Pesticide
KW - Bioconjugation
KW - Oxidative metabolism
KW - EC/MS
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475932
DO - https://doi.org/10.3390/molecules24050898
VL - 24
IS - 5
SP - 898
EP - 910
PB - MDPI
AN - OPUS4-47593
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epping, Ruben
A1 - Falkenhagen, Jana
A1 - Panne, Ulrich
A1 - Hiller, W.
A1 - Gruendling, T.
A1 - Staal, B.
A1 - Lang, C.
A1 - Lamprou, A.
T1 - Simultaneous characterization of poly(acrylic acid) andpolysaccharide polymers and copolymers
N2 - Copolymer products that result from grafting acrylic acid and other hydrophilicmonomers onto polysaccharides have recently gained significant interest in researchand industry. Originating from renewable sources, these biodegradable, low toxicity,and polar copolymer products exhibit potential to replace polymers from fossil sourcesin several applications and industries. The methods usually employed to character-ize these copolymers are, however, quite limited, especially for the measurement ofbulk properties. With more sophisticated applications, for example, in pharmaceu-tics requiring a more detailed analysis of the chemical structure, we describe a newapproach for this kind of complex polymers. Our approach utilizes chromatographyin combination with several detection methods to separate and characterize reactionproducts of the copolymerization of acrylic acid and chemically hydrolyzed starch.These samples consisted of a mixture of homopolymer poly (acrylic acid), homopoly-mer hydrolyzed starch, and – in a lower amount – the formed copolymers. Several chro-matographic methods exist that are capable of characterizing either poly (acrylic acid)or hydrolyzed starch. In contrast, our approach offers simultaneous characterization ofboth polymers. The combination of LC and UV/RI offered insight into the compositionand copolymer content of the samples. Size exclusion chromatography experimentsrevealed the molar mass distribution of homopolymers and copolymers. FTIR inves-tigations confirmed the formation of copolymers while ESI-MS gave more details onthe end groups of hydrolyzed starches and poly (acrylic acids). Evidence of copolymerstructures was obtained through NMR measurements. Finally, two-dimensional chro-matography led to the separation of the copolymers from both homopolymers as wellas the additional separation of sodium clusters. The methods described in this work area powerful toolset to characterize copolymerization products of hydrolyzed starch andpoly(acrylic acid). Together, our approach successfully correlates the physicochemicalproperties of such complex mixtures with their actual composition.
KW - 2D chromatography
KW - LC-MS
KW - SEC
KW - Renewable copolymers
KW - Grafting
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508873
DO - https://doi.org/10.1002/ansa.202000044
SP - 1
EP - 12
PB - Wiley-VCH Verlag-GmbH&Co. KGaA
CY - Weinheim
AN - OPUS4-50887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neuhaus, Birger
A1 - Schmid, Thomas
A1 - Riedel, Jens
T1 - Collection management and study of microscope slides: Storage, profiling, deterioration, restoration procedures, and general recommendations
N2 - A wide range of aspects concerning microscope slides, their preparation, long-time storage, curatorial measures in collections, deterioration, restoration, and study is summarized based on our own data and by analyzing more than 600 references from the 19th century until 2016, 15 patents, and about 100 Materials Safety Data Sheets. Information from systematic zoology, conservation sciences, chemistry, forensic sciences, pathology, paleopathology, applied sciences like food industry, and most recent advances in digital imaging are put together in order to obtain a better understanding of which and possibly why mounting media and coverslip seals deteriorate, how slides can be salvaged, which studies may be necessary to identify a range of ideal mounting media, and how microscope studies can benefit from improvements in developmental biology and related fields. We also elaborate on confusing usage of concepts like that of maceration and of clearing.
The chemical ingredients of a range of mounting media and coverslip seals are identified as much as possible from published data, but this information suffers in so far as the composition of a medium is often proprietary of the manufacturer and may vary over time. Advantages, disadvantages, and signs of deterioration are documented extensively for these media both from references and from our own observations. It turns out that many media degrade within a few years, or decades at the latest, except Canada balsam with a documented life-time of 150 years, Euparal with a documented life-time of 50 years, and glycerol-paraffin mounts sealed with Glyceel, which represents almost the only non-deteriorating and easily reversible mount. Deterioration reveals itself as a yellowing in natural resins and as cracking, crystallization, shrinkage on drying or possibly on loss of a plasticizer, detachment of the coverslip, segregation of the ingredients in synthetic polymers, as well as continued maceration of a specimen to a degree that the specimen virtually disappears. Confusingly, decay does not always appear equally within a collection of slides mounted at the same time in the same medium. The reasons for the deteriorative processes have been discussed but are controversial especially for gum-chloral media. Comparing data from conservation sciences, chemical handbooks, and documented ingredients, we discuss here how far chemical and physical deterioration probably are inherent to many media and are caused by the chemical and physical properties of their components and by chemicals dragged along from previous preparation steps like fixation, chemical maceration, and physical clearing. Some recipes even contain a macerating agent, which proceeds with its destructive work. We provide permeability data for oxygen and water vapor of several polymers contained in mounting media and coverslip seals. Calculation of the penetration rate of moisture in one example reveals that water molecules reach a specimen within a few days up to about a month; this lays to rest extensive discussions about the permanent protection of a mounted specimen by a mounting medium and a coverslip seal.
Based on the ever growing evidence of the unsuitable composition and application of many, and possibly almost all, mounting media, we strongly encourage changing the perspective on microscope slides from immediate usability and convenience of preparation towards durability and reversibility, concepts taken from conservation sciences. Such a change has already been suggested by Upton (1993) more than 20 years ago for gum-chloral media, but these media are still encouraged nowadays by scientists. Without a new perspective, taxonomic biology will certainly lose a large amount of its specimen basis for its research within the next few decades. Modern non-invasive techniques like Raman spectroscopy may help to identify mounting media and coverslip seals on a given slide as well as to understand ageing of the media. An outlook is given on potential future studies.
In order to improve the situation of existing collections of microscope slides, we transfer concepts as per the Smithsonian Collections Standards and Profiling System, developed for insect collections more than 25 years ago, to collections of slides. We describe historical and current properties and usage of glass slides, coverslips, labels, and adhesives under conservational aspects. In addition, we summarize and argue from published and our own experimental information about restorative procedures, including re-hydration of dried-up specimens previously mounted in a fluid medium. Alternatives to microscope slides are considered. We also extract practical suggestions from the literature concerning microscope equipment, cleaning of optical surfaces, health risks of immersion oil, and recent improvements of temporary observation media especially in connection with new developments in digital software.
KW - Re-hydration
KW - Mounting medium
KW - Coverslip seal
KW - Fixation
KW - Maceration
KW - Clearing
KW - Immersion oil
KW - Permeability
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-423322
SN - 978-1-77670-222-0
SN - 978-1-77670-223-7
DO - https://doi.org/10.11646/zootaxa.4322.1.1
SN - 1175-5326
VL - 4322
IS - 1
SP - 1
EP - 173
PB - Magnolia Press
CY - Auckland, Neuseeland
AN - OPUS4-42332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sarhan, R. M.
A1 - Koopman, W.
A1 - Schuetz, R.
A1 - Schmid, Thomas
A1 - Liebig, F.
A1 - Koetz, J.
A1 - Bargheer, M.
T1 - The importance of plasmonic heating for the plasmondriven photodimerization of 4-nitrothiophenol
N2 - Metal nanoparticles form potent nanoreactors, driven by the optical generation of energetic electrons and nanoscale heat. The relative influence of these two factors on nanoscale chemistry is strongly debated. This article discusses the temperature dependence of the dimerization of 4-nitrothiophenol (4-NTP) into 4,4′-dimercaptoazobenzene (DMAB) adsorbed on gold nanoflowers by Surface-Enhanced Raman Scattering (SERS). Raman thermometry shows a significant optical heating of the particles. The ratio of the Stokes and the anti-Stokes Raman signal moreover demonstrates that the molecular temperature during the reaction rises beyond the average crystal lattice temperature of the plasmonic particles. The product bands have an even higher temperature than reactant bands, which suggests that the reaction proceeds preferentially at thermal hot spots. In addition, kinetic measurements of the reaction during external heating of the reaction environment yield a considerable rise of the reaction rate with temperature. Despite this significant heating effects, a comparison of SERS spectra recorded after heating the sample by an external heater to spectra recorded after prolonged illumination shows that the reaction is strictly photo-driven. While in both cases the temperature increase is comparable, the dimerization occurs only in the presence of light. Intensity dependent measurements at fixed temperatures confirm this finding.
KW - Nanoparticles
KW - Plasmonic heating
KW - Raman spectroscopy
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475140
DO - https://doi.org/10.1038/s41598-019-38627-2
SN - 2045-2322
VL - 9
IS - 1
SP - 3060, 1
EP - 8
PB - Nature Publishing Group
AN - OPUS4-47514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vo, P.H.N.
A1 - Vogel, Christian
A1 - Clark, S.M.
A1 - Bishop, D.P.
A1 - Droas, Morten
A1 - Partyka-Jankowska, E.
A1 - Förster, M.W.
A1 - Adam, Christian
A1 - Strezov, V.
A1 - Nguyen, H.T.M.
T1 - PFAS released from the metals recovery process of the lithium-ion battery black mass
N2 - Recycling of Li-ion batteries (LiBs) for metal recovery has gained increasing attention in recent years. Batteries contain per- and polyfluoroalkyl substances (PFAS), however, their behaviour during battery recycling is still not well understood. This study aims to (i) characterise the presence of PFAS in LiBs black mass collected from various recycling factories in Australia, and (ii) investigate the fate of PFAS during the metal recovery process. The concentration of bis-perfluoromethanesulfonimide (bis-FMeSI) (C2) in the black mass was up to 51,000 µg kg−1. Other emerging and legacy PFAS were present, with concentrations varying from 0.1 to100 µg kg−1. The complementary analysis results of extractable organically bound fluorine and Fluorine K-edge X-ray adsorption near-edge structure indicates that the LiBs black mass mainly consists of bis-FMeSI (C2) and LiPF6 as the main PFAS analytes (40 – 80% fluorine equivalent), however other unknown PFAS may also be present. The long-chain PFAS are more difficult to leach compared to the short-chain PFAS. H2SO4 leaches 58% bis-FMeSI which is the highest compared to HNO3 (51%) and HCl (40.4%). During the precipitation stage, adding H2O2 to the H2SO4 (5% v/v) leaching agent increased bis-FMeSI adsorption onto metal precipitates by 40%. Using PiFM analysis, PFAS are found predominantly present as surface-associated species within binder- and carbon-rich domains, and the leaching mechanism is strongly attributable to the disruption of these surface-accessible phases. This work constructs the first baseline for the relevant research about the trade-off between metal recovery and PFAS pollutants in the LiBs recycling process.
KW - Per- and polyfluoroalkyl substances (PFAS)
KW - XANES spectrosocpy
KW - Battery
KW - Combustion ion chromatography
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658268
DO - https://doi.org/10.1016/j.jhazmat.2026.141978
SN - 0304-3894
VL - 509
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Zöllner, Moritz
A1 - Dariz, Petra
A1 - Riedel, Jens
A1 - Schmid, Thomas
ED - Ferreira, E. S. B.
ED - Helfrich, E.
ED - Löffler, I.
ED - Retzmann, A.
ED - Kramell, A. E.
ED - Herm, C.
T1 - Raman spectroscopy as a thermometric tool for the analysis of mortar binders
N2 - The reconstruction of the thermal history of anthropogenic materials is crucial for understanding historical manufacturing techniques. Preparatory parameters such as firing temperature, heating and cooling rates, soaking time, and kiln atmosphere significantly affect the chemical and structural properties of the final product. Comparing historical materials with replicas produced under well-defined laboratory conditions helps identify indicators for these parameters. This comparative approach is greatly enhanced by spectroscopic analyses. Raman spectroscopy has proven to be a powerful tool in this field due to its high sensitivity to crystal-chemical alterations and high spatial resolution.
The results of thermal experiments with gypsum and carbonate raw materials at burning temperatures up to 1000 °C are presented. Precise measurements of Raman peak positions and Raman band widths enable the differentiation of chemically similar phases. Changes in the Raman band parameters are evident even after the subsequent hydration-hardening process of the fired samples, allowing the spectral discrimination of samples treated at different temperatures steps. These findings from the thermal experiments are further applied to Raman micro-spectroscopic mappings of medieval and reenacted mortars. The extracted Raman band parameters show comparable values between the experimental and real-life samples, proving Raman spectroscopy as a suitable tool for estimating the burning temperature and thus elucidating the manufacturing procedures of anthropogenic materials.
T2 - Archäometrie und Denkmalpflege 2025
CY - Dresden, Germany
DA - 18.03.2025
KW - Mineral thermometry
KW - Raman spectroscopy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657853
SN - 0949-4057
VL - 13
SP - 19
EP - 21
PB - Deutsches Bergbau-Museum
CY - Bochum
AN - OPUS4-65785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Walter, Astrid
A1 - Panne, Ulrich
A1 - Weller, Michael G.
T1 - A novel immunoreagent for the specific and sensitive detection of the explosive triacetone triperoxide (TATP)
N2 - Triacetone triperoxide (TATP) is a primary explosive, which was used in various terrorist attacks in the past. For the development of biosensors, immunochemical µ-TAS, electronic noses, immunological test kits, or test strips, the availability of antibodies of high quality is crucial. Recently, we presented the successful immunization of mice, based on the design, synthesis, and conjugation of a novel TATP derivative. Here, the long-term immunization of rabbits is shown, which resulted in antibodies of extreme selectivity and more than 1,000 times better affinity in relation to the antibodies from mice. Detection limits below 10 ng L-1 (water) were achieved. The working range covers more than four decades, calculated from a precision profile. The cross-reactivity tests revealed an extraordinary selectivity of the antibodies—not a single compound could be identified as a relevant cross-reactant. The presented immunoreagent might be a major step for the development of highly sensitive and selective TATP detectors particularly for security applications.
KW - Organic peroxides
KW - Terrorism
KW - Biosensor development
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-240291
UR - http://www.mdpi.com/2079-6374/1/3/93
DO - https://doi.org/10.3390/bios1030093
SN - 2079-6374
VL - 1
IS - 3
SP - 93
EP - 106
PB - MDPI
CY - Basel
AN - OPUS4-24029
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachenberger, Y. U.
A1 - Rosenkranz, D.
A1 - Kriegel, Fabian L.
A1 - Krause, B.
A1 - Matschaß, René
A1 - Reichardt, P.
A1 - Tentschert, J.
A1 - Laux, P.
A1 - Jakubowski, Norbert
A1 - Panne, Ulrich
A1 - Luch, A.
T1 - Tackling Complex Analytical Tasks: An ISO/TS-Based Validation Approach for Hydrodynamic Chromatography Single Particle Inductively Coupled Plasma Mass Spectrometry
N2 - Nano-carrier systems such as liposomes have promising biomedical applications. Nevertheless, characterization of these complex samples is a challenging analytical task. In this study a coupled hydrodynamic chromatography-single particle-inductively coupled plasma mass spectrometry (HDC-spICP-MS) approach was validated based on the technical specification (TS) 19590:2017 of the international organization for standardization (ISO). The TS has been adapted to the hyphenated setup. The quality criteria (QC), e.g., linearity of the calibration, transport efficiency, were investigated. Furthermore, a cross calibration of the particle size was performed with values from dynamic light scattering (DLS) and transmission electron microscopy (TEM). Due to an additional Y-piece, an online-calibration routine was implemented. This approach allows the calibration of the ICP-MS during the dead time of the chromatography run, to reduce the required time and enhance the robustness of the results. The optimized method was tested with different gold nanoparticle (Au-NP) mixtures to investigate the characterization properties of HDC separations for samples with increasing complexity. Additionally, the technique was successfully applied to simultaneously determine both the hydrodynamic radius and the Au-NP content in liposomes. With the established hyphenated setup, it was possible to distinguish between different subpopulations with various NP loads and different hydrodynamic diameters inside the liposome carriers.
KW - Single particle ICP-MS
KW - Nanoparticle characterization
KW - Nano-carrier
KW - Iposomes
KW - Hydrodynamic chromatography (HDC)
KW - Validation
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506609
DO - https://doi.org/10.3390/ma13061447
VL - 13
IS - 6
SP - 1
EP - 14
CY - Basel, Switzerland
AN - OPUS4-50660
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Berger, J.
A1 - Zahedi-Azad, S.
A1 - Voss, H.
A1 - Ernst, O.C.
A1 - Hammerschmidt, R.
A1 - Boeck, T.
A1 - Martin, J.
A1 - Bonse, J.
A1 - Krüger, J.
A1 - Schmid, M.
T1 - CuInSe2-based micro-concentrator solar cells fabricated from In islands grown by laser-assisted MO-CVD
N2 - Micro-concentrator solar cells offer a promising route for reducing material usage in photovoltaics. For Cu(In,Ga)Se2, multiple micro-concentrator manufacturing methods have already been evaluated. All of them involve either high preparation complexity or post-processing to recycle unused precursor or absorber materials. In this work, a new method using laser-assisted metal-organic chemical vapor deposition (LA-MOCVD) was applied to directly grow arrays of indium micro-islands. These arrays are examined and further processed to CuInSe2 micro-solar cell arrays. The geometry and morphology of the islands were investigated and compared before and after absorber formation. The investigation shows that the absorber growth is limited to the vertical direction normal to the substrate surface and that the starting morphology is preserved. Furthermore, the absorber island arrays are processed into micro-modules and operational solar cells are achieved as a proof of principle. These not yet optimized arrays reach a conversion efficiency of 0.65% under 1 sun illumination. Under 17 suns of light concentration, the efficiency gain is between 60 and 250%. This work demonstrates the method's viability for the fabrication of micro-solar cell arrays, with clear potential for achieving higher conversion efficiencies through future optimization.
KW - Micro-concentrator solar cells
KW - Laser-assisted chemical vapor deposition
KW - CISe
KW - Bottom-up fabrication
KW - Resource efficiency
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656711
DO - https://doi.org/10.1016/j.solmat.2026.114284
SN - 0927-0248
VL - 301
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayat, Mehmet Emin
A1 - Nandayapa, Edgar R.
A1 - Tiebe, Carlo
A1 - Unger, Eva L.
A1 - List-Kratochvil, Emil J. W.
T1 - An operando spectroscopic examination of the influence of trace humidity on interdigital back contact metal halide perovskite solar cells
N2 - Controlling trace humidity is vital for both the fabrication and long-term stability of metal halide perovskite (MHP) solar cells. Relevant humidity levels are typically below 10 ppmV, especially in glovebox-based processing and in well-encapsulated devices. Even minute amounts during fabrication can influence crystallization, introducing defects and lowering efficiency. Over time, humidity accelerates degradation of the perovskite layer and internal interfaces, ultimately reducing operational lifetime. Probing these effects at low concentrations under operando conditions is therefore essential for advancing device performance and durability. In this work, we employed a high-precision transfer standard dew point hygrometer to investigate humidity levels between 5 and 35 ppmV in non-encapsulated MHP solar cells. To permit unobstructed water migration during operation, we fabricated interdigital back contact devices. Operando measurements revealed water transport through the perovskite layer and enabled quantification of outgassing. Under trace-humidified conditions, devices exhibited initial charge-carrier quenching, followed by gradual recovery. Notably, the photocurrent response to humidified nitrogen demonstrated that the MHP layer behaves fully reversibly within the explored timescale and across the investigated humidity levels and conditions. These findings establish a systematic operando framework for examining extrinsic stressors in perovskites and highlight opportunities for assessing passivation strategies.
KW - Metal halide perovskite
KW - IBC solar cells
KW - In operando
KW - Extrinsic stressors
KW - Fabrication and encapsulation
KW - Trace humidity
KW - Two-site Stern-Volmer
KW - Charge-carrier quenching
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657560
DO - https://doi.org/10.1039/D6TA01295G
SN - 2050-7496
SP - 1
EP - 16
PB - The Royal Society of Chemistry
CY - London
AN - OPUS4-65756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Morcillo, Dalia
A1 - Winckelmann, Alexander
A1 - Oelze, Marcus
A1 - Leonhardt, Robert
A1 - Schmidt, Anita
A1 - Richter, Silke
A1 - Recknagel, Sebastian
A1 - Vogl, Jochen
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - Exploring Age-Induced Lithium Isotope Fractionation in Lithium-Ion Batteries using Microwave-Induced Cold Nitrogen Plasma Mass Spectrometry
N2 - This study explores Microwave-Inductively Coupled Atmospheric-pressure Plasma Mass Spectrometry (MICAP-MS) as a cost-effective alternative to Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) for analyzing lithium isotopic composition in lithium-ion batteries (LIBs). We investigate the performance of MICAP-MS in measuring Li isotope ratios in new and aged commercial lithium cobalt oxide (LCO) batteries. Our results show that MICAP-MS, operating under cold plasma conditions at 800 W with an 8 mm torch position, achieves results metrologically compatible with MC-ICP-MS, with a precision ranging from 0.6‰ to 3.4‰ for δ7Li values. MICAP-MS benefits from a dielectric resonator for uniform plasma, better ion velocity control, and higher energy efficiency. Optimal settings were identified with dwell times of 10 ms for 6Li and 1 ms for 7Li. The study of LIBs revealed that 6Li migrates towards the anode over multiple charge–discharge cycles, causing 7Li to accumulate in the cathode, a fractionation effect that becomes more pronounced with prolonged cycling. MICAP-MS provides a cost-effective, precise alternative to MC-ICP-MS, with lower operational costs and enhanced portability, advancing the study of isotopic fractionation and aging in lithium-ion batteries.
KW - MICAP-MS
KW - Lithium
KW - Battery aging
KW - Lithium isotopes
KW - Nitrogen plasma
KW - Isotope fractionation
KW - lithium cobalt oxide
KW - LCO
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643777
DO - https://doi.org/10.1039/d4ja00324a
SN - 0267-9477
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ibrahim, Ahmed A. S.
A1 - Bochmann, Arne
A1 - Löhnert, Romy
A1 - Mieller, Björn
A1 - Wilde, Lutz
A1 - Capraro, Beate
A1 - Stelter, Michael
A1 - Töpfer, Jörg
T1 - Performance Enhancement of Ca3Co4O9‐based Transverse Multilayer Thermoelectric Generators for Low‐Power Applications
N2 - Transverse thermoelectric generators (TTEG) enable conversion of thermal into electrical energy with perpendicular directions of the applied temperature gradient and the induced thermoelectric voltage. We report on the fabrication of transverse multilayer thermoelectric generators (TMLTEG) based on p‐type Ca3Co4O9 (CCO) ceramic tapes and printed silver which were conventionally sintered (CS) in air at 920°C or using pressure‐assisted sintering (PAS) at 920°C and 1.5 MPa. The thermoelectric performance of TMLTEGs was evaluated using analytical calculations and simulations. The transverse thermoelectric power factor and thermoelectric figure‐of‐merit of an artificial layered structure composed of CCO and silver were calculated and simulated as functions of layers tilt angle φ and metal‐to‐ceramic thickness ratio. TMLTEG devices with various CCO layer thicknesses of 150 µm, 100 µm, or 33 µm were fabricated and cofired at 920°C in air, which exhibit power outputs of 2.3 mW, 3.2 mW, and 4.1 mW at ΔT = 160 K, respectively. TMLTEGs which were cofired using PAS show a higher power density of 16.4 mW/cm3 at ΔT = 225 K. This enhancement in power (≈ 80%) is crucial for thermoelectric modules comprising multiple TMLTEG devices. The device measurements were compared with 3D simulations.
KW - Ceramic multilayer
KW - Thermoelectric generator
KW - Pressure-assisted sintering
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657868
DO - https://doi.org/10.1111/jace.70656
SN - 0002-7820
VL - 109
IS - 3
SP - 1
EP - 13
PB - Wiley Periodicals LLC.
AN - OPUS4-65786
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Harrab, H.
A1 - Askar, E.
A1 - Franken, T.
A1 - Mauss, F.
T1 - Investigation of the impact of base oils on the auto-ignition behavior of hydrogen–air mixtures
N2 - Using hydrogen as a fuel in internal combustion engines (ICEs) poses several challenges that have yet to be resolved. One issue is the difficulty of controlling combustion, arising from the interaction of lubricant oil during the combustion process. This study examines the effect of lubricant oil on hydrogen's ignition behavior by measuring the minimum auto-ignition temperature (AIT) using a heated constant-volume autoclave at 20 bar. AIT measurements were performed in air and stoichiometric hydrogen–air mixtures to evaluate the effect of the base oil on ignition characteristics. Experimental results demonstrate that auto-ignition of a small volume of 0.2 ml in a total volume of 200 ml of base oil significantly altered the ignitability of H2, reducing the AIT of a stoichiometric H2-air mixture from 460 °C to 270 °C. Further increases in base oil volume up to 1 ml result in a further decrease in AIT in both air (260 – 240 °C) and H2-air mixtures (270 – 250 °C), indicating the need for further investigation into whether this suggests a higher risk of pre-ignition in H2 ICEs. Four common base oils – two mineral oils (Groups II and III) and two synthetic oils (Groups IV (polyalphaolefin) and V (ester)) – were tested to assess their ignition characteristics. The experimental results revealed that all four base oils exhibited similar AITs in air (260 °C) and in hydrogen–air mixtures (270 °C). However, their reactivity differed at a given temperature and pressure; the synthetic oils were less reactive than the mineral oils. Of the synthetic oils tested, the ester base oil exhibited the lowest reactivity, reflected in its longer ignition delay time. Additionally, a numerical investigation was conducted in an adiabatic, constant-volume reactor to examine the impact of base oil surrogates on H2 ignition across the temperature range. The simulated results showed that the base oil surrogates are more reactive than H2 at low temperatures. Of these tested oils, the ester showed the lowest reactivity at a given temperature and pressure, indicating its beneficial potential as a base lubricant for hydrogen engines.
KW - Reactivity
KW - Hydrogen
KW - Pre-ignition
KW - Auto-ignition temperature
KW - Base oil
KW - Ignition delay time
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657683
DO - https://doi.org/10.1016/j.ijhydene.2026.154564
SN - 0360-3199
VL - 226
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-65768
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abad Andrade, Carlos Enrique
A1 - Mimus, S.
A1 - Recknagel, Sebastian
A1 - Jakubowski, N.
A1 - Panne, Ulrich
A1 - Becker-Ross, H.
A1 - Huang, M.-D.
T1 - Determination of organic chlorine in water via AlCl derivatization and detection by high-resolution continuum source graphite furnace molecular absorption spectrometry
N2 - High-resolution continuum source graphite furnace molecular absorption spectrometry (HR-CS-GF-MAS) was employed for determining adsorbable organic chlorine (AOCl) in water. Organic chlorine was indirectly quantified by monitoring the molecular absorption of the transient aluminum monochloride molecule (AlCl) around a wavelength of 261.42 nm in a graphite furnace. An aluminum solution was used as the molecularforming modifier. A zirconium coated graphite furnace, as well as Sr and Ag solutions were applied as modifiers for a maximal enhancement of the absorption signal. The pyrolysis and vaporization temperatures were 600 °C and 2300 °C, respectively. Non-spectral interferences were observed with F, Br, and I at concentrations higher than 6 mg L-1, 50 mg L-1, and 100 mg L-1, respectively. Calibration curves with NaCl, 4-chlorophenol, and trichlorophenol present the same slope and dynamic range, which indicates the chlorine atom specificity of the method. This method was evaluated and validated using synthetic water samples, following the current standard DIN EN ISO 9562:2004 for the determination of the sum parameter adsorbable organic halides (AOX) for water quality. These samples contain 4-chlorophenol as the chlorinated organic standard in an inorganic chloride matrix. Prior to analysis, organic chlorine was extracted from the inorganic matrix via solid-phase extraction with a recovery rate >95%. There were no statistically significant differences observed between measured and known values and for a t-test a confidence level of 95% was achieved. The limits of detection and characteristic mass were found to be 48 and 22 pg, respectively. The calibration curve was linear in the range 0.1–2.5 ng with a correlation coefficient R2 = 0.9986.
KW - Chlorides
KW - Chlorine
KW - Graphite furnace
KW - Spectrometry
KW - Diatomic molecule
KW - Water
KW - AlCl
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534426
DO - https://doi.org/10.1039/D1AY00430A
SN - 1759-9660
VL - 13
IS - 33
SP - 3724
EP - 3730
PB - The Royal Society of Chemistry
CY - London, UK
AN - OPUS4-53442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosenkranz, D.
A1 - Kriegel, F. L.
A1 - Mavrakis, E.
A1 - Pergantis, S. A.
A1 - Reichardt, P.
A1 - Tentschert, J.
A1 - Jakubowski, N.
A1 - Laux, P.
A1 - Panne, Ulrich
A1 - Luch, A.
T1 - Versatile dual-inlet sample introduction system for multi-mode single particle inductively coupled plasma mass spectrometry
N2 - Metal-containing nanoparticles (NP) can be characterized with inductively coupled plasma mass spectrometers (ICP-MS) in terms of their size and number concentration by using the single-particle mode of the instrument (spICP-MS). The accuracy of measurement depends on the setup, operational conditions of the instrument and specific parameters that are set by the user. The transport efficiency of the ICP-MS is crucial for the quantification of the NP and usually requires a reference material with homogenous size distribution and a known particle number concentration.
Currently, NP reference materials are available for only a few metals and in limited sizes. If particles are characterized without a reference standard, the results of both size and particle number may be biased. Therefore, a dual-inlet Setup for characterizing nanoparticles with spICP-MS was developed to overcome this problem. This setup is based on a conventional introduction system consisting of a pneumatic nebulizer (PN) for nanoparticle solutions and a microdroplet Generator (μDG) for ionic calibration solutions. A new and flexible interface was developed to facilitate the coupling of μDG, PN and the ICP-MS system. The interface consists of available laboratory components and allows for the calibration, nanoparticle (NP) characterization and cleaning of the arrangement, while the ICP-MS instrument is still running.
Three independent analysis modes are available for determining particle size and number concentration. Each mode is based on a different calibration principle.
While mode I (counting) and mode III (μDG) are known from the literature, mode II (sensitivity), is used to determine the transport efficiency by inorganic ionic Standard solutions only. It is independent of NP reference materials. The μDG based inlet system described here guarantees superior analyte sensitivities and, therefore, lower detection limits (LOD). The size dependent LODs achieved are less than 15 nm for all NP (Au, Ag, CeO2) investigated.
KW - Spectrometer
KW - Reference
KW - Calibration
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536121
DO - https://doi.org/10.3791/61653
SN - 1940-087X
IS - 163
SP - 1
EP - 19
PB - MyJoVE Corporation
CY - Cambridge, MA, USA
AN - OPUS4-53612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dariz, P.
A1 - Schmid, Thomas
T1 - Trace compounds in Early Medieval Egyptian blue carry information on provenance, manufacture, application, and ageing
N2 - Only a few scientific evidences for the use of Egyptian blue in Early Medieval wall paintings in Central and Southern Europe have been reported so far. The monochrome blue fragment discussed here belongs to the second church building of St. Peter above Gratsch (South Tyrol, Northern Italy, fifth/ sixth century A.D.). Beyond cuprorivaite and carbon black (underpainting), 26 accessory minerals down to trace levels were detected by means of Raman microspectroscopy, providing unprecedented insights into the raw materials blend and conversion reactions during preparation, application, and ageing of the pigment. In conjunction with archaeological evidences for the manufacture of Egyptian blue in Cumae and Liternum and the concordant statements of the antique Roman writers Vitruvius and Pliny the Elder, natural impurities of the quartz sand speak for a pigment produced at the northern Phlegrean Fields (Campania, Southern Italy). Chalcocite (and chalcopyrite) suggest the use of a sulphidic copper ore, and water-insoluble salts a mixed-alkaline flux in the form of plant ash. Not fully reacted quartz crystals partly intergrown with cuprorivaite and only minimal traces of silicate glass portend solid-state reactions predominating the chemical reactions during synthesis, while the melting of the raw materials into glass most likely played a negligible role.
KW - Egyptian blue
KW - Raman microspectroscopy
KW - Spectoscopic imaging
KW - Cuprorivaite
KW - Amorphous carbon
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-537591
DO - https://doi.org/10.1038/s41598-021-90759-6
VL - 11
SP - 1
EP - 12
PB - Nature Portfolio
AN - OPUS4-53759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riedel, Soraya
A1 - Hülagü, Deniz
A1 - Bennet, Francesca
A1 - Carl, Peter
A1 - Flemig, Sabine
A1 - Schmid, Thomas
A1 - Schenk, J. A.
A1 - Hodoroaba, Vasile-Dan
A1 - Schneider, Rudolf
T1 - Electrochemical Immunomagnetic Ochratoxin A Sensing: Steps Forward in the Application of 3,3’,5,5’- Tetramethylbenzidine in Amperometric Assays
N2 - Electrochemical methods offer great promise in meeting the demand for user-friendly on-site devices for Monitoring important parameters. The food industry often runs own lab procedures, for example, for mycotoxin analysis, but it is a major goal to simplify analysis, linking analytical methods with smart technologies. Enzyme-linked immunosorbent assays, with photometric detection of 3,3’,5,5’-tetramethylbenzidine (TMB),form a good basis for sensitive detection. To provide a straightforward approach for the miniaturization of the detectionstep, we have studied the pitfalls of the electrochemical TMB detection. By cyclic voltammetry it was found that the TMB electrochemistry is strongly dependent on the pH and the electrode material. A stable electrode response to TMB could be achieved at pH 1 on gold electrodes. We created a smartphonebased, electrochemical, immunomagnetic assay for the detection of ochratoxin A in real samples, providing a solid basis forsensing of further analytes.
KW - Ochratoxin A
KW - Amperometry
KW - Cyclic voltammetry
KW - Electrochemistry
KW - Immunoassay
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530421
DO - https://doi.org/10.1002/celc.202100446
N1 - Geburtsname von Riedel, Soraya: Höfs, S. - Birth name of Riedel, Soraya: Höfs, S.
VL - 8
IS - 13
SP - 2597
EP - 2606
AN - OPUS4-53042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steinbeck, Christoph
A1 - Jung, Nicole
A1 - Bach, Felix
A1 - Neumann, Steffen
A1 - Herres-Pawlis, Sonja
A1 - Liermann, Johannes
A1 - Koepler, Oliver
A1 - Bannwarth, Christoph
A1 - Bender, Theo
A1 - Bocklitz, Thomas
A1 - Boehm, Franziska
A1 - Bonatto Minella, Christian
A1 - Biedermann, Frank
A1 - Brack, Werner
A1 - Cunha, Ricardo
A1 - Czodrowski, Paul
A1 - Eberl, Franziska
A1 - Engel, Thomas
A1 - Engstfeld, Albert
A1 - Fischer, Tillmann G.
A1 - Friedrich, Pascal
A1 - Glorious, Frank
A1 - Golub, Benjamin
A1 - Grathwol, Christoph
A1 - Haag, Rainer
A1 - Hunold, Johannes
A1 - Jacob, Christoph
A1 - Johannsen, Jochen
A1 - Jollife, John
A1 - Kast, Stefan
A1 - Kettner, Carsten
A1 - Kuhn, Stefan
A1 - Lanza, Giacomo
A1 - Lisec, Jan
A1 - Manolikakes, Georg
A1 - Mata, Ricardo
A1 - Meiler, Jens
A1 - Müller, Matthias
A1 - Müller-Pfefferkorn, Ralph
A1 - Ortmeyer, Jochen
A1 - Patterson, Wendy
A1 - Pleiss, Jürgen
A1 - Riedel, Annalisa
A1 - Riedel, Jens
A1 - Schatzschneider, Ulrich
A1 - Schuster, Leonie
A1 - Seeberger, Peter
A1 - Seibert, Johann-Nikolaus
A1 - Stadler, Peter
A1 - Zeitler, Kirsten
T1 - Proposal NFDI4Chem 2025-2030 In the National Research Data Infrastructure (NFDI) — Our Vision: All Chemists Publish FAIR Data
N2 - The first funding period of NFDI4Chem established a robust foundation for research data management (RDM) in chemistry by promoting FAIR data principles and creating a cohesive infrastructure to capture well-annotated data early in the lab through electronic lab notebooks (ELNs) and making this data available in public repositories. Key achievements include standardised data formats and metadata, a federated repository environment, and improved data visibility and accessibility. Training programs and outreach have significantly increased awareness and adoption of best RDM practices. In the second funding period, the consortium aims to advance these achievements by consolidating this infrastructure, developing a model for its sustainable maintenance and operation, and fostering cultural change for its widespread adoption. Goals include ensuring seamless data workflows from laboratories to open repositories, enhancing interoperability, and supporting innovative research through AI-ready data. The work plan is organised into six task areas (TAs). TA1 (Management) provides leadership and supports all other TAs in achieving their objectives. TA2 (Smart Lab) aims to develop a fully digital research environment, including an ELN as a modular platform. This environment will support data collection, management, storage, analysis, and sharing. Integrating devices and external resources will enable seamless data transfer to repositories. TA3 (Repositories) will consolidate the repository ecosystem. The goal is to integrate repositories into a federated system for better accessibility and interoperability, ensuring long-term data availability and sustainability. TA4 (Metadata, Data Standards, and Publication Standards) focuses on developing and promoting new data and metadata standards in an international community process. This includes applying ontologies to create a semantic foundation for linking research data, making it machine-readable and enabling knowledge graphs. TA5 (Community and Training) is dedicated to fostering a cultural shift towards digital chemistry through continuous engagement, collecting requirements, and providing extensive training and support through workshops and open education resources. It will promote FAIR-compliant machine learning applications, embedding RDM into academic curricula to ensure future scientists are well-versed in these practices. TA6 (Synergies and Cross-Cutting Topics) aims to enhance collaboration across NFDI consortia and beyond. This includes developing ontologies, terminology services, the search service, and other cross-cutting solutions, integrating these developments into existing infrastructure, enabling interdisciplinary data harmonisation and fostering machine learning applications.
KW - Research Data Management
KW - FAIR
KW - Chemistry
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-648540
DO - https://doi.org/10.3897/rio.11.e177037
SN - 2367-7163
VL - 11
SP - 1
EP - 100
PB - Pensoft Publishers
AN - OPUS4-64854
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winckelmann, Alexander
A1 - Morcillo Garcia-Morato, Dalia
A1 - Richter, Silke
A1 - Recknagel, Sebastian
A1 - Riedel, Jens
A1 - Vogl, Jochen
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - Determination of lithium in human serum by isotope dilution atomic absorption spectrometry
N2 - The therapeutic dose of lithium (Li) compounds, which are widely used for the treatment of psychiatric and hematologic disorders, is close to its toxic level; therefore, drug monitoring protocols are mandatory. Herein, we propose a fast, simple, and low-cost analytical procedure for the traceable determination of Li concentration in human serum, based on the monitoring of the Li isotope dilution through the partially resolved isotope shift in its electronic transition around 670.80 nm using a commercially available high-resolution continuum source graphite furnace atomic absorption spectrometer. With this technique, serum samples only require acidic digestion before analysis. The procedure requires three measurements—an enriched 6Li spike, a mixture of a certified standard solution and spike, and a mixture of the sample and spike with a nominal 7Li/6Li ratio of 0.82. Lanthanum has been used as an internal spectral standard for wavelength correction. The spectra are described as the linear superposition of the contributions of the respective isotopes, each consisting of a spin-orbit doublet, which can be expressed as Gaussian components with constant spectral position and width and different relative intensity, reflecting the isotope ratio in the sample. Both the spectral constants and the correlation between isotope ratio and relative band intensity have been experimentally obtained using commercially available materials enriched with Li isotopes. The Li characteristic mass (mc) obtained corresponds to 0.6 pg. The procedure has been validated using five human serum certified reference materials. The results are metrologically comparable and compatible to the certified values. The measurement uncertainties are comparable to those obtained by the more complex and expensive technique, isotope dilution mass spectrometry.
KW - Lithium
KW - Human serum
KW - Isotope dilution
KW - Atomic absorption spectrometry
KW - High-resolution continuum source graphite furnace atomic absorption spectrometry
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532446
DO - https://doi.org/10.1007/s00216-021-03636-6
VL - 414
IS - 1
SP - 251
EP - 256
PB - Springer
CY - Berlin
AN - OPUS4-53244
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Szymoniak, Paulina
A1 - Schönhals, Andreas
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - The Origin of Delayed Polymorphism in Molecular Crystals Under Mechanochemical Conditions
N2 - We show that mechanochemically driven polymorphic transformations can require extremely long induction periods, which can be tuned from hours to days by changing ball milling energy. The robust design and interpretation of ball milling experiments must account for this unexpected kinetics that arises from energetic phenomena unique to the solid state. Detailed thermal analysis, combined with DFT simulations, indicates that these marked induction periods are associated with processes of mechanical activation. Correspondingly, we show that the pre‐activation of reagents can also lead to marked changes in the length of induction periods. Our findings demonstrate a new dimension for exerting control over polymorphic transformations in organic crystals. We expect mechanical activation to have a much broader implication across organic solid‐state mechanochemistry.
KW - General Chemistry
KW - Catalysis
KW - Organic Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-589219
DO - https://doi.org/10.1002/chem.202302150
SN - 0947-6539
SP - e202302150
PB - Wiley
AN - OPUS4-58921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sentker, K.
A1 - Yildirim, Arda
A1 - Lippmann, M.
A1 - Zantop, A. W.
A1 - Bertram, F.
A1 - Hofmann, T.
A1 - Seeck, O. H.
A1 - Kityk, A.
A1 - Mazza, M. G.
A1 - Schönhals, Andreas
A1 - Huber, P.
T1 - Self-assembly of liquid crystals in nanoporous solids for adaptive photonic metamaterials
N2 - Nanoporous media exhibit structures significantly smaller than the wavelengths of visible light and can thus act as photonic metamaterials. Their optical functionality is not determined by the properties of the base materials, but rather by tailored, multiscale structures, in terms of precise pore shape, geometry, and orientation. Embedding liquid crystals in pore space provides additional opportunities to control light–matter interactions at the single-pore, meta-atomic scale. Here, we present temperature-dependent 3D reciprocal space mapping using synchrotron-based X-ray diffraction in combination with high-Resolution birefringence experiments on disk-like mesogens (HAT6) imbibed in self-ordered arrays of parallel cylindrical pores 17 to 160 nm across in monolithic anodic aluminium oxide (AAO). In agreement with Monte Carlo computer simulations we observe a remarkably rich self-assembly behaviour, unknown from the bulk state. It encompasses transitions between the isotropic liquid state and discotic stacking in linear columns as well as circular concentric ring formation perpendicular and parallel to the pore axis. These textural transitions underpin an optical birefringence functionality, tuneable in magnitude and in sign from positive to negative via pore size, pore surface-grafting and temperature. Our study demonstrates that the advent of large-scale, self-organised nanoporosity in monolithic solids along with confinement-controllable phase behaviour of liquid-crystalline matter at the single-pore scale provides a reliable and accessible tool to design materials with adjustable optical anisotropy, and thus offers versatile pathways to finetune polarisation-dependent light propagation speeds in materials. Such a tailorability is at the core of the emerging field of transformative optics, allowing, e.g., adjustable light absorbers and extremely thin metalenses.
KW - Discotic Liquid Crystals
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-499601
DO - https://doi.org/10.1039/c9nr07143a
SP - 1
EP - 14
PB - RSC Royal Society of Chemistry
AN - OPUS4-49960
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winckelmann, Alexander
A1 - Nowak, S.
A1 - Richter, Silke
A1 - Recknagel, Sebastian
A1 - Riedel, Jens
A1 - Vogl, Jochen
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - High-Resolution Atomic Absorption Spectrometry Combined With Machine Learning Data Processing for Isotope Amount Ratio Analysis of Lithium
N2 - An alternative method for lithium isotope amount ratio analysis based on a combination of high-resolution atomic absorption spectrometry and spectral data analysis by machine learning (ML) is proposed herein. It is based on the well-known isotope shift of approximately 15 pm for the electronic transition 22P←22S at around the wavelength of 670.8 nm, which can be measured by the state-of-the-art high-resolution continuum source graphite furnace atomic absorption spectrometry. For isotope amount ratio analysis, a scalable tree boosting ML algorithm (XGBoost) was employed and calibrated using a set of samples with 6Li isotope amount fractions, ranging from 0.06 to 0.99 mol mol–1, previously determined by a multicollector inductively coupled plasma mass spectrometer (MC-ICP-MS). The calibration ML model was validated with two certified reference materials (LSVEC and IRMM-016). The procedure was applied toward the isotope amount ratio determination of a set of stock chemicals (Li2CO3, LiNO3, LiCl, and LiOH) and a BAM candidate reference material NMC111 (LiNi1/3Mn1/3Co1/3O2), a Li-battery cathode material. The results of these determinations were compared with those obtained by MC-ICP-MS and found to be metrologically comparable and compatible. The residual bias was −1.8‰, and the precision obtained ranged from 1.9 to 6.2‰. This precision was sufficient to resolve naturally occurring variations, as demonstrated for samples ranging from approximately −3 to +15‰. To assess its suitability to technical applications, the NMC111 cathode candidate reference material was analyzed using high-resolution continuum source atomic absorption spectrometry with and without matrix purification. The results obtained were metrologically compatible with each other.
KW - Lithium
KW - Isotope
KW - Machine learning
KW - Algorithms
KW - Reference material
KW - AAS
KW - Atomic Absorption Spectrometry
PY - 2021
DO - https://doi.org/10.1021/acs.analchem.1c00206
SN - 1520-6882
VL - 93
IS - 29
SP - 10022
EP - 10030
PB - American Chemical Society
CY - Washington, DC, USA
AN - OPUS4-53028
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neamtu, Mariana
A1 - Nadejde, C.
A1 - Hodoroaba, Vasile-Dan
A1 - Schneider, Rudolf
A1 - Verestiuc, L.
A1 - Panne, Ulrich
T1 - Functionalized magnetic nanoparticles: Synthesis, characterization, catalytic application and assessment of toxicity
N2 - Cost-effective water cleaning approaches using improved Treatment technologies, for instance based on catalytic processes with high activity catalysts, are urgently needed. The aim of our study was to synthesize efficient Fenton-like photo-catalysts for rapid degradation of persistent organic micropollutants in aqueous medium. Iron-based nanomaterials were chemically synthesized through simple procedures by immobilization of either iron(II) oxalate (FeO) or iron(III) citrate (FeC) on magnetite (M) nanoparticles stabilized with polyethylene glycol (PEG). Various investigation techniques were performed in order to characterize the freshly prepared catalysts. By applying advanced oxidation processes, the effect of catalyst dosage, hydrogen peroxide concentration and UV-A light exposure were examined for Bisphenol A (BPA) conversion, at laboratory scale, in mild conditions. The obtained results revealed that BPA degradation was rapidly enhanced in the presence of low-concentration H2O2, as well as under UV-A light, and is highly dependent on the surface characteristics of the catalyst. Complete photo-degradation of BPA was achieved over the M/PEG/FeO catalyst in less than 15 minutes. Based on the catalytic performance, a hierarchy of the tested catalysts was established: M/PEG/FeO > M/PEG/FeC > M/PEG. The results of cytotoxicity assay using MCF-7 cells indicated that the aqueous samples after treatment are less cytotoxic.
KW - Bisphenol A
KW - Magnetic nanocatalyst
KW - Endocrine disruptor
KW - Nanoparticle
KW - Photodegradation
KW - Fenton
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-448297
DO - https://doi.org/10.1038/s41598-018-24721-4
SN - 2045-2322
VL - 8
SP - Article 6278, 1
EP - 11
PB - Springer Nature
CY - London
AN - OPUS4-44829
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hachenberger, Y. U.
A1 - Rosenkranz, Daniel
A1 - Kromer, C.
A1 - Krause, B. C.
A1 - Dreiack, N.
A1 - Kriegel, F. L.
A1 - Kozmenko, E.
A1 - Jungnickel, H.
A1 - Tentschert, J.
A1 - Bierkandt, F. S.
A1 - Laux, P.
A1 - Panne, Ulrich
A1 - Luch, A.
T1 - Nanomaterial Characterization in Complex Media - Guidance and Application
N2 - A broad range of inorganic nanoparticles (NPs) and their dissolved ions possess a possible toxicological risk for human health and the environment. Reliable and robust measurements of dissolution effects may be influenced by the sample matrix, which challenges the analytical method of choice. In this study, CuO NPs were investigated in several dissolution experiments. Two analytical techniques (dynamic light scattering (DLS) and inductively-coupled plasma mass spectrometry (ICP-MS)) were used to characterize NPs (size distribution curves) time-dependently in different complex matrices (e.g., artificial lung lining fluids and cell culture media). The advantages and challenges of each analytical approach are evaluated and discussed. Additionally, a direct-injection single particle (DI sp)ICP-MS technique for assessing the size distribution curve of the dissolved particles was developed and evaluated. The DI technique provides a sensitive response even at low concentrations without any dilution of the complex sample matrix. These experiments were further enhanced with an automated data evaluation procedure to objectively distinguish between ionic and NP events.
With this approach, a fast and reproducible determination of inorganic NPs and ionic backgrounds can be achieved. This study can serve as guidance when choosing the optimal analytical method for NP characterization and for the determination of the origin of an adverse effect in NP toxicity.
KW - Nanon
KW - Characterization
KW - SpICP-MS
KW - Matrix
KW - Dissolution
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572138
DO - https://doi.org/10.3390/nano13050922
VL - 13
IS - 5
SP - 1
EP - 19
AN - OPUS4-57213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emteborg, H.
A1 - Florian, D.
A1 - Choquette, S.
A1 - Ellison, S. L. R.
A1 - Fernandes-Whaley, M.
A1 - Mackay, L.
A1 - McCarron, P.
A1 - Panne, Ulrich
A1 - Sander, S. G.
A1 - Kim, S.-K.
A1 - Held, A.
A1 - Linsinger, T.
A1 - Trapmann, S.
T1 - Cooperation in publicly funded reference material production
N2 - The meeting was organised by the European Commission’s Joint Research Centre and held at the JRC-Geel site on 22–23 February 2018. It was a follow-up of a similar meeting held in 2009. The objective of the meeting was to exchange information about ongoing publicly funded reference material (RM) production, identify areas of interest for future specific RMs, including certified reference material (CRM) developments, investigate potential areas of collaboration, and to identify areas which may be of a lower importance in the future for a specific RM producer. The benefit of exchanging such information is to avoid duplication of efforts in RM production, make better use of public funds by potentially matching competencies, and to address problems that are common to publicly funded RM producers.
T2 - Meeting regarding cooperation in publicly funded reference material production, European Commission's Joint Research Centre
CY - Geel, Belgium
DA - 22.02.2018
KW - Public funding
KW - Reference materials
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470206
DO - https://doi.org/10.1007/s00769-018-1349-1
SN - 0949-1775
SN - 1432-0517
VL - 23
IS - 6
SP - 371
EP - 377
PB - Springer
CY - Berlin
AN - OPUS4-47020
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Morcillo, Dalia
A1 - Winckelmann, Alexander
A1 - Frick, Daniel A.
A1 - Jacobsen, Lars
A1 - Seger, Tino
A1 - Florek, Stefan
A1 - Richter, Silke
A1 - Vogl, Jochen
A1 - Recknagel, Sebastian
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - Lithium isotope ratio analysis of geological samples using atomic absorption spectrometry with improved spectral resolution
N2 - This study introduces an improved spectrometric method with enhanced precision to determine isotope ratios in geological samples without chromatographic separation. Firstly, the improvement is achieved by increasing the spectral resolution of the spectrometer applied in well-known high-resolution continuum source atomic absorption spectrometry (HR-CS-AAS). The resulting resolving power and linear dispersion of the upgraded setup, which is denoted in the following as HR+CS-AAS, is well adapted to the line widths of the Li isotope components we investigated. Secondly, our proposed method combines optical absorption spectrometry with machine learning data analysis using an extreme gradient boosting algorithm (XGBoost). This method was applied to analyze certified geological reference materials with δLSVEC(7Li/6Li) (hereafter δ7Li) values ranging from −0.5 ‰ to 4.5 ‰. With a pixel related optical resolving power of λ/∆λ ≈ 780 000, we obtain precisions in δ7Li measurements from 1.0 ‰ to 2.5 ‰. The method is validated by comparing the results with multi-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), confirming its metrological compatibility. This work presents a fast, robust, and reliable method for δ7Li measurement in geological samples.
KW - Isotope
KW - High-resolution continuum source atomic absorption spectroscopy
KW - Lithium
KW - Machine learning
KW - Echelle spectrometer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611807
DO - https://doi.org/10.1016/j.sab.2024.107013
VL - 220
SP - 1
EP - 5
PB - Elsevier BV
AN - OPUS4-61180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sötebier, Carina
A1 - Bierkandt, Frank
A1 - Rades, Steffi
A1 - Jakubowski, Norbert
A1 - Panne, Ulrich
A1 - Weidner, Steffen
T1 - Sample loss in asymmetric flow field-flow fractionation coupled to inductively coupled plasma-mass spectrometry of silver nanoparticles
N2 - In this work, sample losses of silver nanoparticles (Ag NPs) in asymmetrical flow field-flow fractionation (AF4) have been systematically investigated with the main focus on instrumental conditions like focusing and cross-flow parameters as well as sample concentration and buffer composition. Special attention was drawn to the AF4 membrane. For monitoring possible silver depositions on the membrane, imaging laser ablation coupled to inductively coupled plasma mass spectrometry (LA-ICP-MS) was used. Our results show that the sample residue on the membrane was below 0.6% of the total injected amount and therefore could be almost completely avoided at low sample concentrations and optimized conditions. By investigation of the AF4 flows using inductively coupled plasma mass spectrometry (ICP-MS), we found the recovery rate in the detector flow under optimized conditions to be nearly 90%, while the cross-flow, slot-outlet flow and purge flow showed negligible amounts of under 0.5%. The analysis of an aqueous ionic Ag standard solution resulted in recovery rates of over 6% and the ionic Ag content in the sample was found to be nearly 8%. Therefore, we were able to indicate the ionic Ag content as the most important source of sample loss in this study.
KW - Asymmetric flow filed-flow fractionation
KW - ICP-MS
KW - Nanoparticles
KW - Sample loss
KW - Quantification
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-336171
DO - https://doi.org/10.1039/c5ja00297d
SN - 0267-9477
SN - 1364-5544
VL - 30
IS - 10
SP - 2214
EP - 2222
PB - Royal Society of Chemistry
CY - London
AN - OPUS4-33617
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dariz, P.
A1 - Wortmann, U. G.
A1 - Vogl, Jochen
A1 - Schmid, Thomas
T1 - Beautiful Pietàs in South Tyrol (Northern Italy): local or imported works of art?
N2 - The study, dedicated to Beautiful Pietàs conserved in South Tyrol (Northern Italy), aims to establish, for the first time, a connection between Austroalpine raw materials and the high-fired gypsum mortars constituting the Gothic figure groups in question. The origin and chronology of this stylistically and qualitatively differing ensemble have been subject of art historical debate for nearly a century. The discourse is dominated by three main hypotheses: itinerary of an Austrian artist versus itinerary of the work of art created in an artist’s workshop in Austria versus itinerary of the stylistic vocabulary via graphical or three-dimensional models. The comparison of the δ34S values and the 87Sr/86Sr ratios of the gypsum mortars and Austroalpine sulphate deposits (in a compilation of own reference samples and literature data) points to the exploitation of sediments in the Salzkammergut and possibly also in the evaporite district of the Eastern Calcareous Alps, thus evidencing the import of the sculptures and not the activities of local South Tyrolean or itinerant artists. Two geochronological units are distinguishable: The Pietà in the Church St. Martin in Göflan can be assigned to Upper Permian raw material, whereas the metrologically consistent sculptures in the Church of Our Lady of the Benedictine Abbey Marienberg and in the Chapel St. Ann in Mölten correlate with deposits of the Early Triassic (or the Lower-Middle Triassic transition). The medieval gypsum mortars also differ in their mineralogical characteristics, i.e. in their geologically related minor components, as in the first case, characterised by a significant proportion of primary anhydrite, natural carbonate impurities mainly consist of calcite (partly converted to lime-lump-like aggregates), whereas in the second group dolomite (or rather its hydration products after pyrometamorphic decomposition) predominates, accompanied by celestine, quartz and potassium feldspar. The Pietà in the Cathedral Maria Himmelfahrt in Bozen turned out to be made of Breitenbrunn calcareous sandstone (Leitha Mountains, Burgenland, Austria), which is why the sample is not considered in the geochemical analysis.
KW - High-fired gypsum mortar
KW - Sulphur isotope
KW - Strontium isotope
KW - Polarised light microscopy
KW - Raman microspectroscopy
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545610
DO - https://doi.org/10.1186/s40494-022-00678-6
SN - 2050-7445
VL - 10
IS - 1
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-54561
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mondal, Saikat
A1 - Prakash, Swayam
A1 - Riechers, Birte
A1 - Maaß, Robert
A1 - Emmerling, Franziska
A1 - Bhattacharya, Biswajit
T1 - Comprehensive Structure–Property Mapping of Tuned Mechanical Flexibility in Organic Cocrystals
N2 - Mechanically flexible crystals offer unique opportunities for adaptive materials, yet predictive control over their responses remains a major challenge. Here, we present a chemically unified series of 4-nitrophenol-based cocrystals, cocrystallized with bipyridyl linkers of varied geometries, to systematically map structure–property relationships. Subtle variations in interplanar angles and intermolecular interactions, such as π–π stacking and hydrogen bonding, enable tuning of mechanical responses ranging from brittle fracture to different extents of elastic bending and plastic bending or twistability. This design differs from previous strategies that relied primarily on van der Waals interactions or halogen bonding to impart mechanical compliance to organic crystals. Structural analysis, supported by energy framework calculations, explains the divergent mechanical behaviors. Notably, the studied cocrystal series spans all four canonical structure–property quadrants, manifested through mechanical flexibility, photoluminescence activity, or both. This systematic and comparative study highlights the delicate interplay between molecular packing and supramolecular interactions, providing structure–property correlations that inform emerging design principles for multifunctional crystalline materials for targeted applications.
KW - Aromatic compounds
KW - Crystals
KW - Deformation
KW - Flexibility
KW - Plastics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658364
DO - https://doi.org/10.1021/acs.cgd.5c01550
SN - 1528-7483
VL - 26
IS - 3
SP - 1370
EP - 1377
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-65836
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rappsilber, Tim
A1 - Krüger, Simone
A1 - Raspe, Tina
A1 - Reclo, Rudolf
A1 - Schweiger, Hans-Georg
T1 - Toxic gas emission in electric vehicles: What a battery fire means for occupant safety
N2 - This work investigates the ability of occupants to escape from a battery electric vehicle during a thermal runaway of the traction battery initiated by nail penetration. Such events generate intense fires and large amounts of toxic gases, rapidly reducing the time available for safe evacuation. In controlled full-scale outdoor experiments on two identical mid-range battery electric vehicles, the smoke gas composition inside the cabin is examined. Using FTIR spectrometers and an oxygen analyzer, temporal and spatial concentrations of organic carbonates, hydrocarbons, hydrogen fluoride, hydrogen cyanide, acetylene, and oxygen are measured. Sampling locations include the driver's breathing zone, the right rear passenger's breathing zone, and the exterior right rear wheel housing. The study further evaluates occupant's escape capability using the fractional effective dose (FED) model in accordance with ISO 13571. Results show that toxic gases can reach harmful concentrations within minutes after smoke enters the cabin, though smoke entry times vary widely with fire progression. Differences in fire development and smoke dispersion strongly affect FED values and thus the time available for self-rescue. Overall, the findings provide an important basis for assessing occupant safety during battery electric vehicle fires and highlight the need for improved mitigation strategies.
KW - Vehicle
KW - Toxic gases
KW - Fire
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658397
DO - https://doi.org/10.1016/j.firesaf.2026.104717
SN - 1873-7226
VL - 162
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-65839
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pedersen, Angus
A1 - Zhu, Jinjie
A1 - Barrio, Jesús
A1 - Parker, Joseph
A1 - Hunter, Robert D.
A1 - Haigh, Sarah J.
A1 - Fellinger, Tim-Patrick
A1 - Stephens, Ifan E. L.
A1 - Titirici, Maria-Magdalena
T1 - Contribution of Mg-templated porosity to activity and durability in Fe–N–C O 2 reduction catalysts
N2 - Atomically dispersed Fe in N-doped carbon (Fe–N–C) catalysts are leading platinum-group-metal-free candidates for the O2 reduction reaction in proton exchange membrane fuel cells (PEMFCs). Zeolitic imidazolate framework (ZIF-8) derived Fe–N–C present the most promising performance; however, they possess a narrow distribution of small micropores, which limits active site accessibility. Here, to induce hierarchical porosity in Fe–N–C, we report a systematic study on MgCl2·6H2O-templated ZIF-8-derived Fe–N–C catalysts for the O2 reduction reaction. MgCl2·6H2O addition induced complete Zn removal, collapse of the ZIF-8 framework, and formation of large micro- and mesopores, with graphene-like structures. N content was markedly reduced, with conversion from pyridinic to pyrrolic N species. Rotating disc electrode tests showed a progressive increase in O2 reduction activity with MgCl2·6H2O, which is strongly correlated (R2 = 0.98) to the formation of large micropores and small mesopores (1–4 nm). This introduces an indirect structure–activity design principle for Fe–N–Cs. The enhanced Fe–N–C porosity also leads to increased degradation rates under accelerated stress test conditions, which we attributed to the oxidation of disordered carbon domains and active Fe loss. This study highlights a key trade-off between porosity-driven O2 reduction activity and durability in Fe–N–C catalysts.
KW - Porosity
KW - Single atom
KW - Oxygen reduction
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657549
DO - https://doi.org/10.1039/d5ma01488c
SN - 2633-5409
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65754
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klippel, Andrea
A1 - Hofmann-Böllinghaus, Anja
A1 - Piechnik, Kira
A1 - Heydick, Lukas
A1 - Wu, Hongyi
A1 - Köhler, Florian
A1 - Klaffke, Benjamin
T1 - Experimental Analysis of Fire Behavior in Pine Forests and Agricultural Fields: Large‐Scale Tests Conducted Within the European TREEADS Project
N2 - Two large‐scale experiments investigated fire spread mechanisms in vegetation ground fires in a pine forest and an agricultural field within the European TREEADS project. The tests, conducted in Saxony‐Anhalt and Brandenburg, targeted regions with dry, sandy soils and extensive pine stands and aim to improve suppression strategies and wildfire research. The forest experiment was conducted on a 16 × 22 m plot with line ignition using a gasoline‐diesel mix. Fire spread was documented with drone‐based video and infrared imaging. Ninety‐six thermocouples and two gas sensors were mounted on trees, and a mobile FTIR spectrometer enabled real‐time smoke analysis. A tilled and foam‐treated strip prevented uncontrolled spread. Under stable weather conditions (23°C, light wind, low soil moisture), a consistent temperature rise and distinct combustion phases were observed. Smoldering dominated in areas with mosses, grasses, and deadwood, with intermittent flaming, limited flame heights (< 0.5 m), and substantial smoke production. Peak temperatures exceeded 500°C, and CO concentrations reached 238 ppm, though wind turbulence complicated gas sampling. The second experiment on a cut agricultural field near Nauen involved burning approximately 700 m2 using a 20 m ignition line aligned with wind direction. Drone‐based infrared monitoring captured rapid spread on the stubble surface. The results underscore the variability and measurement challenges of outdoor fires and highlight the necessity of continued large‐scale experiments to support physical and numerical wildfire modeling. These findings provide essential empirical data for evaluating vegetation‐specific burning behavior, improving sensor deployment strategies, and refining validation approaches for next‐generation wildfire spread models under central European fuel and weather conditions, and supporting decision‐making in wildfire management.
KW - Wildfire
KW - Pine
KW - Crop
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654199
DO - https://doi.org/10.1002/fam.70045
SN - 0308-0501
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-65419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Häusler, Ines
A1 - Schwarze, C.
A1 - Umer Bilal, M.
A1 - Valencia Ramirez, D.
A1 - Hetaba, W.
A1 - Darvishi Kamachali, Reza
A1 - Skrotzki, Birgit
T1 - Precipitation of T1 and theta′ Phase in Al‐4Cu‐1Li‐0.25Mn During Age Hardening: Microstructural Investigation and Phase‐Field Simulation
N2 - Experimental and phase field studies of age hardening response of a high purity Al‐4Cu‐1Li‐0.25Mn‐alloy (mass %) during isothermal aging are conducted. In the experiments, two hardening phases are identified: the tetragonal θ′ (Al₂Cu) phase and the hexagonal T1 (Al₂CuLi) phase. Both are plate shaped and of nm size. They are analyzed with respect to the development of their size, number density and volume fraction during aging by applying different analysis techniques in TEM in combination with quantitative microstructural analysis. 3D phase‐field simulations of formation and growth of θ′ phase are performed in which the full interfacial, chemical and elastic energy contributions are taken into account. 2D simulations of T1 phase are also investigated using multi‐component diffusion without elasticity. This is a first step toward a complex phase‐field study of T1 phase in the ternary alloy. The comparison between experimental and simulated data shows similar trends. The still unsaturated volume fraction indicates that the precipitates are in the growth stage and that the coarsening/ripening stage has not yet been reached.
KW - Al‐Cu‐Li‐alloy
KW - Precipitates
KW - Age hardening
KW - Volume fraction
KW - Number density
KW - Microstructure
KW - Phase‐field modeling
KW - Elasticity
KW - Multi‐component diffusion
KW - Growth kinetics
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390473
DO - https://doi.org/10.3390/ma10020117
SN - 1996-1944
VL - 10
IS - 2
SP - Article 117, 1
EP - 21
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-39047
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, Sebastian
A1 - Chuenban, Yuttapong
A1 - Schartel, Bernhard
T1 - Exploring the Modes of Action of Phosphorus-Based Flame Retardants in Polymeric Systems
N2 - Phosphorus-based flame retardants were incorporated into different, easily preparable matrices, such as polymeric thermoset resins and paraffin as a proposed model for polyolefins and investigated for their flame retardancy performance. The favored mode of action of each flame retardant was identified in each respective system and at each respective concentration. Thermogravimetric analysis was used in combination with infrared spectroscopy of the evolved gas to determine the pyrolysis behavior, residue formation and the release of phosphorus species. Forced flaming tests in the cone calorimeter provided insight into burning behavior and macroscopic residue effects. The results were put into relation to the phosphorus content to reveal correlations between phosphorus concentration in the gas phase and flame inhibition performance, as well as phosphorus concentration in the residue and condensed phase activity. Total heat evolved (fire load) and peak heat release rate were calculated based on changes in the effective heat of combustion and residue, and then compared with the measured values to address the modes of action of the flame retardants quantitatively. The quantification of flame inhibition, charring, and the protective layer effect measure the non-linear flame retardancy effects as functions of the phosphorus concentration. Overall, this screening approach using easily preparable polymer systems provides great insight into the effect of phosphorus in different flame retarded polymers, with regard to polymer structure, phosphorus concentration, and phosphorus species.
KW - Flame retardants
KW - Flame inhibition
KW - Cone calorimeter
KW - Aluminum diethyl phosphinate
KW - Polyester
KW - PMMA
KW - Epoxy resin
KW - Red phosphorus
KW - BDP
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402731
DO - https://doi.org/10.3390/ma10050455
SN - 1996-1944
VL - 10
IS - 5
SP - 455, 1
EP - 455, 23
PB - MDPI
AN - OPUS4-40273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Matzen, Melissa
A1 - Kandola, B.
A1 - Huth, Christian
A1 - Schartel, Bernhard
T1 - Influence of flame retardants on the melt dripping behaviour of thermoplastic polymers
N2 - Melt flow and dripping of the pyrolysing polymer melt can be both a benefit and a detriment during a fire. In several small-scale fire tests addressing the ignition of a defined specimen with a small ignition source, well-adjusted melt flow and dripping are usually beneficial to pass the test. The presence of flame retardants often changes the melt viscosity crucially. The influence of certain flame retardants on the dripping behaviour of four commercial polymers, poly(butylene terephthalate) (PBT), polypropylene (PP), polypropylene modified with ethylene-propylene rubber (PP-EP) and polyamide 6 (PA 6), is analysed based on an experimental monitoring of the mass loss due to melt dripping, drop size and drop temperature as a function of the furnace temperature applied to a rod-shaped specimen. Investigating the thermal transition (DSC), thermal and thermo-oxidative decomposition, as well as the viscosity of the polymer and collected drops completes the investigation. Different mechanisms of the flame retardants are associated with their influence on the dripping behaviour in the UL 94 test. Reduction in decomposition temperature and changed viscosity play a major role. A flow limit in flame-retarded PBT, enhanced decomposition of flame-retarded PP and PP-EP and the promotion of dripping in PA 6 are the salient features discussed.
KW - Fire retardant
KW - Viscosity
KW - Melt dripping
KW - Reaction-to-small-flame
KW - UL 94
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-338941
DO - https://doi.org/10.3390/ma8095267
SN - 1996-1944
VL - 8
IS - 9
SP - 5621
EP - 5646
PB - MDPI
CY - Basel
AN - OPUS4-33894
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tang, S.
A1 - Wachtendorf, Volker
A1 - Klack, Patrick
A1 - Qian, Lijun
A1 - Dong, Y.
A1 - Schartel, Bernhard
T1 - Enhanced flame-retardant effect of montmorillonite/phosphaphenanthrene compound in an epoxy thermoset
N2 - A phosphaphenanthrene and triazinetrione group containing flame retardant (TAD) is combined with organically modified montmorillonite (OMMT) in epoxy resin thermosets (EP) to improve the performance of the flame-retardant system. When only 1 wt% OMMT/4 wt% TAD is introduced into the EP, the limited oxygen index (LOI) rises from 26% to 36.9% and a V-0 rating is achieved in a UL 94 test. The decomposition and pyrolysis products in the gas phase and condensed phase were characterized using thermogravimetry-Fourier transform infrared spectroscopy (TG-FTIR). The influence on the decomposition of EP, such as the increase in char yield, is limited with the incorporation of OMMT; a large amount of the phosphorus is released into the gas phase. The flame-retardant effect evaluation based on cone calorimeter data testified that OMMT improves the protective-barrier effect of the fire residue of OMMT/TAD/EP on the macroscopic scale, while TAD mainly causes flame inhibition. The fire residues showed a corresponding macroscopic appearance (digital photo) and microstructure (scanning electron microscope [SEM] results). The protective barrier effect of OMMT and the flame-inhibition effect of TAD combined to exert a superior flame-retardant effect, resulting in sufficient flame-retardant performance of OMMT/TAD/EP
KW - Flame retardant
KW - Nanocomposite
KW - DOPO
KW - Thermoset
KW - Epoxy resin
KW - TG-FTIR
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-388865
DO - https://doi.org/10.1039/c6ra25070j
SN - 2046-2069
VL - 7
IS - 2
SP - 720
EP - 728
AN - OPUS4-38886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Fedelich, Bernard
A1 - Kühn, Hans-Joachim
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
ED - Iacoviello, Francesco
T1 - Modeling the lifetime reduction due to the superposition of TMF and HCF loadings in cast iron alloys
N2 - The superposition of small amplitude, high frequency loading cycles (HCF) to slow, large amplitude loading cycles (TMF) can significantly reduce the fatigue life. In this work, the combined TMF+HCF loading has been experimentally investigated for a cast iron alloy. In particular, the influence of the HCF frequency of the HCF amplitude and of the location of the superposed HCF cycles has been assessed. It was observed that the HCF frequency has a limited impact on the TMF fatigue life. On the other side, the HCF-strain amplitude has a highly non-linear influence on the TMF fatigue life. A simple estimate for the fatigue life reduction due to the superposed HCF cycles has been derived from fracture mechanics considerations. It is assumed that the number of propagation cycles up to failure can be neglected after a threshold for the HCF loading has been reached. The model contains only two adjustable parameters and can be combined with any TMF life prediction model. The model predictions are compared with the test results for a large range of TMF+HCF loading conditions.
T2 - 21st European Conference on Fracture, ECF21
CY - Catania, Italy
DA - 20.06.2016
KW - Thermomechanical Fatigue (TMF); High Cycle Fatigue (HCF); Cast iron; Fatigue assessment
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-369550
DO - https://doi.org/doi:10.1016/j.prostr.2016.06.274
VL - 2
SP - 2190
EP - 2197
PB - Elsevier
CY - Radarweg 29, 1043 NX Amsterdam, The Netherlands,
AN - OPUS4-36955
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Beier, H. Th.
T1 - Fatigue strength and life determination of weldments based on fracture mechanics
N2 - The paper provides an overview on the results of a German cluster project on the use of fracture mechanics to the determination of the fatigue strength of weldments with fatigue cracks originating at the weld toes. The approach includes (a) a concept for short crack propagation for which the common ΔK concept is not applicable and the crack closure effects are still being gradually build-up, (b) a method for determining fatigue life relevant initial crack sizes as they are needed in any fracture mechanics analysis and (c) multiple cracking and crack coalescence at load levels higher than the endurance limit. The analyses are stochastically performed. Both, the endurance limit and the finite life branch of the S-N curve are determined.
Besides a brief introduction into the approach, validation examples are presented. These comprise different weldment types (butt welds, cross joints and longitudinal stiffened plates), two steels (S355NL and S960QL) of quite different strengths, different weld geometries due to different welding techniques (WIG, MAG), as-welded and stress relieved welds and different stress ratios varying from R = -1 to R = 0.5.
T2 - FDMD 2017
CY - Lecco, Italy
DA - 19.09.2017
KW - Weldments
KW - Fatigue strength
KW - Fracture mechanics
KW - Initial crack size
KW - Short crack propagation
KW - Multiple crack propagation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438500
DO - https://doi.org/10.1016/j.prostr.2017.11.106
SN - 2452-3216
VL - 7
SP - 407
EP - 414
PB - ScienceDirect
CY - Lecco, Italy
AN - OPUS4-43850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Beier, T.
A1 - Tchoffo Ngoula, D.
T1 - Approximation of the crack driving force for cracks at notches under static and cyclic loading
N2 - The work deals with the efficient calculation of the elastic-plastic crack driving force (J-integral for monotonic loading andΔJ-integral under cyclic loading) for short cracks at notches as essential parameter for the reliable static and fatigue assessment of notched structures. The J- or ΔJ-integral is calculated based on analytical solutions for stress intensity factors, estimated by means of well-known weight function solutions in the case of cracks under power-law stress distributions. A plasticity-correction function is applied to the stress intensity factors to obtain the final expression of the crack driving force. The comparison between analytical solutions and finite element calculations in case of cracks at the weld toe in welded joints shows good agreement.
T2 - 2nd International Conference on Structural Integrity
CY - Funchal, Madeira, Portugal
DA - 04.09.2017
KW - Structural integrity
KW - Fracture mechanics
KW - Crack driving force
KW - Notches
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-425577
DO - https://doi.org/10.1016/j.prostr.2017.07.111
SN - 2452-3216
VL - 5
SP - 875
EP - 882
PB - Elsevier B.V.
AN - OPUS4-42557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sobol, Oded
A1 - Straub, F.
A1 - Wirth, Thomas
A1 - Holzlechner, G.
A1 - Böllinghaus, Thomas
A1 - Unger, Wolfgang
T1 - Real Time Imaging of Deuterium in a Duplex Stainless Steel Microstructure by Time-of-Flight SIMS
N2 - For more than one century, hydrogen assisted degradation of metallic microstructures has been identified as origin for severe technical component failures but the mechanisms behind have not yet been completely understood so far. Any in-situ observation of hydrogen transport phenomena in microstructures will provide more details for further elucidation of these degradation mechanisms. A novel experiment is presented which is designed to elucidate the permeation behaviour of deuterium in a microstructure of duplex stainless steel (DSS). A hydrogen permeation cell within a TOF-SIMS instrument enables electrochemical charging with deuterium through the inner surface of the cell made from DSS. The outer surface of the DSS permeation cell exposed to the vacuum has been imaged by TOF-SIMS vs. increasing time of charging with subsequent chemometric treatment of image data. This in-situ experiment showed evidently that deuterium is permeating much faster through the ferrite phase than through the austenite phase. Moreover, a direct proof for deuterium enrichment at the austenite-ferrite interface has been found.
KW - Characterization and analytical techniques
KW - Corrosion
KW - Imaging technique
KW - Mass spectrometry
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-353872
UR - http://www.nature.com/articles/srep19929
DO - https://doi.org/10.1038/srep19929
SN - 2045-2322
VL - 6
IS - 19929
SP - 1
EP - 7
PB - nature publishing group
CY - London, United Kingdom
AN - OPUS4-35387
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lenz, J. U.
A1 - Pospiech, D.
A1 - Komber, H.
A1 - Korwitz, A.
A1 - Kobsch, O.
A1 - Paven, M.
A1 - Albach, R. W.
A1 - Günther, Martin
A1 - Schartel, Bernhard
T1 - Effective halogen-free flame-retardant additives for crosslinked rigid polyisocyanurate foams: Comparison of chemical structures
N2 - The impact of phosphorus-containing flame retardants (FR) on rigid polyisocyanurate (PIR) foams is studied by systematic variation of the chemical structure of the FR, including non-NCO-reactive and NCO-reactive dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO)- and 9,10 dihydro-9-oxa-10 phosphaphenanthrene-10-oxide (DOPO)-containing compounds, among them a number of compounds not reported so far. These PIR foams are compared with PIR foams without FR and with standard FRs with respect to foam properties, thermal decomposition, and fire behavior. Although BPPO and DOPO differ by just one oxygen atom, the impact on the FR properties is very significant: when the FR is a filler or a dangling (dead) end in the PIR polymer network, DOPO is more effective than BPPO. When the FR is a subunit of a diol and it is fully incorporated in the PIR network, BPPO delivers superior results.
KW - Flame retardant;
KW - Dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide; BPPO
KW - 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide; DOPO
KW - Polyisocyanurate; PIR
KW - Rigid foam
KW - Cone calorimeter
KW - Pudovik reaction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567712
DO - https://doi.org/10.3390/ma16010172
SN - 1996-1944
VL - 16
IS - 1
SP - 1
EP - 22
PB - MDPI
CY - Basel
AN - OPUS4-56771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schönherr, J. A.
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Geilen, M. B.
A1 - Klein, M.
A1 - Oechsner, M.
T1 - Robust determination of fatigue crack propagation thresholds from crack growth data
N2 - The robust determination of the threshold against fatigue crack propagation DKth is of paramount importance in fracture mechanics based fatigue assessment procedures. The standards ASTM E647 and ISO 12108 introduce operational definitions of DKth based on the crack propagation rate da/dN and suggest linear fits of logarithmic DK– da/dN test data to calculate DKth. Since these fits typically suffer from a poor representation of the actual curvature of the crack propagation curve, a method for evaluating DKth using a nonlinear function is proposed. It is shown that the proposed method reduces the artificial conservativeness induced by the evaluation method as well as the susceptibility to scatter in test data and the influence of test data density.
KW - Fatigue crack propagation threshold
KW - ISO 12108
KW - ASTM E647
KW - Data evaluation methods
KW - Experimental determination
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552153
DO - https://doi.org/10.3390/ma15144737
SN - 1996-1944
VL - 15
IS - 14
SP - 1
EP - 21
PB - MDPI
CY - Basel
AN - OPUS4-55215
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Hanke, Thomas
A1 - Skrotzki, Birgit
T1 - Semantic Representation of Low‐Cycle‐Fatigue Testing Data Using a Fatigue Test Ontology and ckan.kupferdigital Data Management System
N2 - Addressing a strategy for publishing open and digital research data, this article presents the approach for streamlining and automating the process of storage and conversion of research data to those of semantically queryable data on the web. As the use case for demonstrating and evaluating the digitalization process, the primary datasets from low‐cycle‐fatigue testing of several copper alloys are prepared. The fatigue test ontology (FTO) and ckan.kupferdigital data management system are developed as two main prerequisites of the data digitalization process. FTO has been modeled according to the content of the fatigue testing standard and by reusing the basic formal ontology, industrial ontology foundry core ontology, and material science and engineering ontology. The ckan.kupferdigital data management system is also constructed in such a way that enables the users to prepare the protocols for mapping the datasets into the knowledge graph and automatically convert all the primary datasets to those machine‐readable data which are represented by the web ontology language. The retrievability of the converted digital data is also evaluated by querying the example competency questions, confirming that ckan.kupferdigital enables publishing open data that can be highly reused in the semantic web.
KW - Accessible
KW - CKAN
KW - Interoperable
KW - Digitalizations
KW - Ontologies
KW - Reusable data
KW - Fatigue testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604991
UR - https://onlinelibrary.wiley.com/doi/10.1002/adem.202400675
DO - https://doi.org/10.1002/adem.202400675
SN - 1527-2648
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-60499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chan, Yin Yam
A1 - Ma, C.
A1 - Zhou, F.
A1 - Hu, Y.
A1 - Schartel, Bernhard
T1 - A liquid phosphorous flame retardant combined with expandable graphite or melamine in flexible polyurethane foam
N2 - A systematic series of flexible polyurethane foams (FPUF) with different concentrations of flame retardants, bis([dimethoxyphosphoryl]methyl) phenyl phosphate (BDMPP), and melamine (MA) or expandable graphite (EG) was prepared. The mechanical properties of the FPUFs were evaluated by a universal testing machine. The pyrolysis behaviors and the evolved gas analysis were done by thermogravimetric analysis (TGA) and TGA coupled with Fourier-transform infrared (TG-FTIR), respectively. The fire behaviors were studied by limiting oxygen index (LOI), UL 94 test for horizontal burning of cellular materials (UL 94 HBF), and cone calorimeter measurement. Scanning electronic microscopy (SEM) was used to examine the cellular structure's morphology and the postfire char residue of the FPUFs. LOI and UL 94 HBF tests of all the flame retarded samples show improved flame retardancy. BDMPP plays an essential role in the gas phase because it significantly reduces the effective heat of combustion (EHC). This study highlights the synergistic effect caused by the combination of BDMPP and EG. The measured char yield from TGA is greater than the sum of individual effects. No dripping phenomenon occurs during burning for FPUF-BDMPP-EGs, as demonstrated by the result of the UL 94 HBF test. EG performs excellently on smoke suppression during burning, as evident in the result of the cone calorimeter test. MA reduces the peak heat release rate (pHRR) significantly. The synergistic effect of the combination of BDMPP and EG as well as MA offers an approach to enhance flame retardancy and smoke suppression.
KW - Bis([dimethoxyphosphoryl]methyl) phenyl phosphate
KW - Expandable graphite
KW - Flexible polyurethane foam
KW - melamine
KW - phosphorous flame retardant
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541840
DO - https://doi.org/10.1002/pat.5519
SN - 1099-1581
VL - 33
IS - 1
SP - 326
EP - 339
PB - Wiley
AN - OPUS4-54184
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Jürgens, Maria
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Creep-fatigue of P92 in service-like tests with combined stress- and strain-controlled dwell times
N2 - Complex service-like relaxation- and creep-fatigue tests with strain- and stress-controlled dwells and fatigue cycle durations of approx. 2200 s were performed exemplarily on a grade P92 steel at 620 ◦C in this study. The results indicate deviations in the prevailing creep mechanisms of long-term relaxation and creep dwells, affecting subsequent dwells, load shifts, and the macroscopic softening behavior quite differently. In addition, fracture surfaces and longitudinal metallographic sections reveal intergranular crack growth for complex loading with stress-controlled dwells, whereas complex strain-controlled tests enhance oxidation and transgranular crack propagation. These findings substantiate the limited transferability of relaxation-fatigue to creep-fatigue conditions.
KW - Tempered martensite-ferritic steel
KW - P92
KW - Dwell periods
KW - Creep-fatigue interaction
KW - Stress relaxation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564239
DO - https://doi.org/10.1016/j.ijfatigue.2022.107381
SN - 0142-1123
VL - 168
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-56423
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Chaudhuri, Somsubhro
A1 - Purayil, Sruthi Krishna Kunji
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Nielsen, Sören
T1 - Thermography-Assisted Mechanical Testing of Cold-Spray (AM) Repair
N2 - Cold Spray Additive Manufacturing (CSAM) is a solid-state process that is being increasingly used for structural repairs in aerospace and energy sectors. It enables the deposition of dense material at low temperatures by accelerating metal particles to supersonic velocities, thereby reducing thermal distortion. However, the structural integrity of CSAM repairs—particularly at the interface between the deposited layer and the substrate—remains a critical concern. Various post-treatments and characterization methods have been explored to optimize performance. While X-ray Computed Tomography (XCT) is effective for sub-surface inspection, it cannot be applied in situ during mechanical testing. Digital Image Correlation (DIC), a surface-based method, also lacks sub-surface sensitivity. To address this, Infrared Thermography (IRT) was employed alongside DIC during the tensile and fatigue testing of aluminum CSAM-repaired specimens. A cooled IRT camera operating at 200 FPS captured thermal data, with lock-in processing subsequently applied in post-processing. IRT successfully detected early interfacial damage and enabled the tracking of crack propagation, which was later confirmed through fracture surface analysis. This extended abstract presents findings from fatigue tests using IRT.
T2 - 18th International Workshop on Advanced Infrared Technology and Applications (AITA 2025)
CY - Kobe, Japan
DA - 15.09.2025
KW - Thermography
KW - Thermografie
KW - Thermal stress analysis
KW - Cold spray
KW - Damage detection
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642299
DO - https://doi.org/10.3390/proceedings2025129018
VL - 129
IS - 1
SP - 1
EP - 5
PB - MDPI
CY - Basel
AN - OPUS4-64229
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sunder, S.
A1 - Jauregui Rozo, Maria
A1 - Inasu, S.
A1 - Meinel, Dietmar
A1 - Schartel, Bernhard
A1 - Ruckdäschel, H.
T1 - Effect of Ammonium Polyphosphate/Silicate Content on the Postfire Mechanics of Epoxy Glass-Fiber Composites Using Facile Chocolate Bar-Inspired Structures
N2 - This study investigates the postfire mechanical properties of epoxy glass-fiber
reinforced composites (EP GFRCs) using increasing concentrations of ammonium polyphosphate (APP) and inorganic silicate (InSi) to modify the char and fire residue. A facile chocolate bar-inspired structure was introduced for fire exposure and subsequent flexural testing of the GFRCs. The resin matrix used here was a diglycidyl ether of bisphenol-A (DGEBA) resin, cured with dicyandiamide (DICY), and accelerated by Urone. The microstructures of the degraded composites after three-point bending tests, were evaluated using scanning electron microscopy (SEM) and x-ray computed tomography (XCT) imaging. A previous study showed that increasing the APP and InSi content significantly enhanced flame retardancy, via improved char formation under fire conditions. However, flexural properties and fire resistance were adversely affected after fire exposure, highlighting a trade-off effect. Fiber breakage and delamination of the composites increased upon failure with increasing APP + InSi content in the composite due to unconsolidated char. The experimental values for the postfire flexural mechanics were in good agreement with the two-layer model proposed in literature. This paper presents a preliminary basis for postfire mechanical testing of epoxy composites for use in fire-safe structures, using a combination of standardized testing norms.
KW - Flame retardants
KW - Post-fire
KW - Epoxy
KW - Gass fiber composites
KW - Prepregs
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627176
DO - https://doi.org/10.1002/fam.3280
SN - 0308-0501
SN - 1099-1018
VL - 49
IS - 3
SP - 329
EP - 346
PB - Wiley
AN - OPUS4-62717
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Baer, Wolfram
A1 - Wagener, Rainer
A1 - Kiyak, Yusuf
T1 - Betriebsfestigkeit und Bruchverhalten von bainitischen Schmiedestählen
N2 - Die neue Generation von bainitischen Schmiedestählen bietet auf der einen Seite ein erhebliches Festigkeitspotenzial, das es im Sinne des Leichtbaus auch für zyklisch belastete Sicherheitsbauteile zu heben gilt. Auf der anderen Seite geht mit dieser Festigkeitssteigerung im Vergleich zu Vergütungsstählen ein Verlust an Duktilität und Zähigkeit einher. Am Beispiel des Demonstratorbauteils Achsschenkel ging das Forschungsvorhaben der Frage nach, wie ein Freigabeprozess zu gestalten ist, damit das Festigkeitspotenzial der neuen Stähle zuverlässig ausgenutzt werden kann. Als Ergebnis wird eine Vorgehensweise dargestellt, die den Eigenschaften der neuen Generation von Schmiedestählen Rechnung trägt, um den sicheren Betrieb der Komponenten zu gewährleisten.
KW - Bainitischer Schmiedestahl
KW - Bruchmechanik
KW - Sicherheit
KW - Betriebsfestigkeit
KW - Bauteilauslegung
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594296
SN - 2366-5106
SP - 50
EP - 54
PB - Industrieverband Massivumformung e. V
CY - Hagen
AN - OPUS4-59429
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittrich, Bettina
A1 - Wartig, K.-A.
A1 - Mülhaupt, R.
A1 - Schartel, Bernhard
T1 - Flame-retardancy properties of intumescent ammonium poly(phosphate) and mineral filler magnesium hydroxide in combination with graphene
N2 - Thermally reduced graphite oxide (TRGO), containing only four single carbon layers on average, was combined with ammonium polyphosphate (APP) and magnesium hydroxide (MH), respectively, in polypropylene (PP). The nanoparticle's influence on different flame-retarding systems and possible synergisms in pyrolysis, reaction to small flame, fire behavior and mechanical properties were determined. TRGO has a positive effect on the yield stress, which is decreased by both flame-retardants and acts as a synergist with regard to Young's modulus. The applicability and effects of TRGO as an adjuvant in combination with conventional flame-retardants depends strongly on the particular flame-retardancy mechanism. In the intumescent system, even small concentrations of TRGO change the viscosity of the pyrolysing melt crucially. In case of oxygen index (OI) and UL 94 test, the addition of increasing amounts of TRGO to PP/APP had a negative impact on the oxygen index and the UL 94 classification. Nevertheless, systems with only low amounts (≤1 wt%) of TRGO achieved V-0 classification in the UL 94 test and high oxygen indices (>31 vol%). TRGO strengthens the residue structure of MH and therefore functions as a strong synergist in terms of OI and UL 94 classification (from HB to V-0).
KW - Graphene
KW - Intumescence
KW - Ammonium polyphosphate
KW - Magnesium hydroxide
KW - Synergy
KW - Polypropylene
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-320685
DO - https://doi.org/10.3390/polym6112875
SN - 2073-4360
VL - 6
IS - 11
SP - 2875
EP - 2895
PB - MDPI
CY - Basel
AN - OPUS4-32068
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Engelking, Lorenz
A1 - Madia, Mauro
A1 - Schröpfer, Dirk
A1 - Kruse, Julius
A1 - Saliwan Neumann, Romeo
A1 - Kannengießer, Thomas
T1 - Influence of Ultrasonic-Assisted Milling on Surface Integrity and Fatigue Strength of a Low Alloy Steel
N2 - The milling process significantly influences the surface integrity of metallic components through machining induced near surface residual stresses. Modern hybrid machining processes, such as ultrasonic-assisted milling (USAM), offer the potential to induce beneficial near-surface compressive residual stresses compared to the near-surface tensile residual stresses typically resulting from conventional milling (CM). This study investigates the effects of USAM compared to CM on the near-surface residual stress state and fatigue performance of a S355J2C low-alloy steel. Milling experiments and subsequent rotating bending tests revealed that USAM significantly reduces cutting force by approximately 45% and induces near-surface compressive re sidual stresses as low as −733MPa. This leads to a significant improvement in fatigue strength estimated in approximately 34% compared to polished specimens and 11% compared to the CM. These findings highlight the potential of USAM to enhance the fatigue performance of components made of steel.
KW - Fatigue strength
KW - Residual stress
KW - Surface integrity
KW - Surface roughness
KW - Ultrasonic-assisted milling
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657358
DO - https://doi.org/10.1111/ffe.70259
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-65735
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Beier, H.T.
T1 - A model for the determination of the fatigue life in technical alloys containing large and small defects
N2 - The determination of the fatigue life in technical alloys containing large and small defects must rely on a propagation model which accounts for short and long crack growth. Recently an analytical model which incorporates propagation in the short crack regime and plastic correction for the crack driving force has been presented by two of the authors.
This work is intended to show further validation of the model, taking into account data sets for different materials with different testing conditions.
Despite the assumptions about missing parameters, the value of which had to be taken from the literature, the predictions showed a fairly good approximation of the fatigue lives. A possible interpretation of the results in terms of multiple crack initiation and propagation at higher loads is proposed.
T2 - EFC20 - 20th European conference on fracture
CY - Trondheim, Norway
DA - 30.06.2014
KW - Fatigue strength
KW - Crack propagation
KW - Short cracks
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-311961
DO - https://doi.org/10.1016/j.mspro.2014.06.082
SN - 2211-8128
VL - 3
SP - 493
EP - 498
PB - Curran
CY - Red Hook, NY, USA
AN - OPUS4-31196
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Stegemann, Robert
A1 - Sonntag, Nadja
A1 - Kreutzbruck, Marc
A1 - Skrotzki, Birgit
ED - Brune, M.
ED - Buffière, J.Y.
ED - Morel, F.
ED - Nadot, Y.
T1 - Self-magnetic-leakage field detection using magneto-optical sensor technique
N2 - Measurement of spontaneous magnetic stray field signals has been reported to be a promising tool for capturing macro-scale information of deformation states, defects and stress concentration zones in a material structure. This paper offers a new method for self-magnetic leakage field detection using a magneto-optical (MO) hand-held microscope. Its sensor has a dynamic field range between ±0.05 and ±2 kA/m and a lateral optical resolution of approx. 10 µm. We examined flat tensile test specimens of metastable austenitic steel AISI 304. Static tensile tests were repeatedly interrupted at various predetermined states of strain and the magnetic information was measured by the MO system. Comparative measurements using a high-precision magnetic field GMR-sensor, verify the outstanding capability of the MO microscope regarding spatial resolution of magnetic fields.
T2 - FDMDII-JIP 2014 - 14th International spring meeting
CY - Paris, France
DA - 06.11.2014
KW - Magneto-optical sensor
KW - Metal magnetic memory
KW - GMR
KW - NDT
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-326911
SN - 978-2-7598-1274-5
DO - https://doi.org/10.1051/matecconf/20141204010
N1 - Serientitel: Materials science, Engineering and Chemistry – Series title: Materials science, Engineering and Chemistry
VL - 12
SP - 04010-1
EP - 04010-3
PB - EDP Sciences
AN - OPUS4-32691
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jürgens, Maria
A1 - Olbricht, Jürgen
A1 - Fedelich, Bernard
A1 - Skrotzki, Birgit
T1 - Low Cycle Fatigue and Relaxation Performance of Ferritic–Martensitic Grade P92 Steel
N2 - Due to their excellent creep resistance and good oxidation resistance, 9–12% Cr ferritic–martensitic stainless steels are widely used as high temperature construction materials in power plants. However, the mutual combination of different loadings (e.g., creep and fatigue), due to a “flexible” operation of power plants, may seriously reduce the lifetimes of the respective components. In the present study, low cycle fatigue (LCF) and relaxation fatigue (RF) tests performed on grade P92 helped to understand the behavior of ferritic–martensitic steels under a combined loading. The softening and lifetime behavior strongly depend on the temperature and total strain range. Especially at small strain amplitudes, the lifetime is seriously reduced when adding a hold time which indicates the importance of considering technically relevant small strains.
KW - Ferritic–martensitic steel
KW - P92
KW - Low cycle fatigue
KW - Relaxation fatigue
KW - Cyclic softening
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-473905
DO - https://doi.org/10.3390/met9010099
VL - 9
IS - 1
SP - 99, 1
EP - 25
PB - MDPI
AN - OPUS4-47390
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zirnstein, Benjamin
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
T1 - Mechanical and fire properties of multicomponent flame retardant EPDM rubbers using aluminum trihydroxide, ammonium polyphosphate, and polyaniline
N2 - In this study, multicomponent flame retardant systems, consisting of Ammonium polyphosphate (APP), aluminum trihydroxide (ATH), and polyaniline (PANI), were used in ethylene propylene diene monomer (EPDM) rubber. The multicomponent system was designed to improve flame retardancy and the mechanical properties of the rubber compounds, while simultaneously reducing the amount of filler. PANI was applied at low loadings (7 phr) and combined with the phosphorous APP (21 phr) and the mineral flame retardant ATH (50 phr). A comprehensive study of six EPDM rubbers was carried out by systematically varying the fillers to explain the impact of multicomponent flame retardant systems on mechanical properties. The six EPDM materials were investigated via the UL 94, limiting oxygen index (LOI), FMVSS 302, glow wire tests, and the cone calorimeter, showing that multicomponent flame retardant systems led to improved fire performance.
In cone calorimeter tests the EPDM/APP/ATH/PANI composite reduced the maximum average rate of heat emission (MARHE) to 142 kW·m-2, a value 50% lower than that for the unfilled EPDM rubber. Furthermore, the amount of phosphorus in the residues was quantified and the mode of action of the phosphorous flame retardant APP was explained. The data from the cone calorimeter were used to determine the protective layer effect of the multicomponent flame retardant systems in the EPDM compounds.
KW - EPDM
KW - Rubber
KW - Flame retardant
KW - Polyaniline
KW - Aluminum trihydroxide (ATH)
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-482769
DO - https://doi.org/10.3390/ma12121932
SN - 1996-1944
VL - 12
IS - 12
SP - 1932, 1
EP - 22
PB - MDPI
AN - OPUS4-48276
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Markwart, J. C.
A1 - Wurm, F. R.
A1 - Schartel, Bernhard
T1 - Hyperbranched phosphorus flame retardants: multifunctional additives for epoxy resins
N2 - We successfully synthesized multifunctional P-based hyperbranched polymeric flame retardants (hb-FRs) with varying oxygen-to-nitrogen (O : N) content and characterized them via 1H and 31P NMR and GPC. Their miscibility in epoxy resins (EP) and impact on glass-transition temperatures (Tg) were determined via differential scanning calorimetry (DSC). Using thermogravimetric and evolved gas Analysis (TGA, TG-FTIR), pyrolysis gas chromatography/mass spectrometry (Py-GC-MS), hot stage FTIR, flammability tests UL-94 and LOI, fire testing via cone calorimetry, residue analysis via scanning electron microscopy (SEM) and elemental analysis, detailed decomposition mechanisms and modes of action are proposed. hb-polymeric FRs have improved miscibility and thermal stability, leading to high FR performance even at low loadings. Polymeric, complex FRs increase flame retardancy, mitigate negative effects of low molecular weight variants, and can compete with commercial aromatic FRs. The results illustrate the role played by the chemical structure in flame retardancy and highlight the potential of hb-FRs as multifunctional additives.
KW - Flame retardant
KW - Hyperbranched
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486589
DO - https://doi.org/10.1039/c9py00737g
SN - 1759-9962
SN - 1759-9954
VL - 10
IS - 31
SP - 4346
EP - 4358
PB - RSC
AN - OPUS4-48658
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markwart, J. C.
A1 - Battig, Alexander
A1 - Velencoso, M. M.
A1 - Pollok, D.
A1 - Schartel, Bernhard
A1 - Wurm, F. R.
T1 - Aromatic vs. Aliphatic Hyperbranched Polyphosphoesters as Flame Retardants in Epoxy Resins
N2 - The current trend for future flame retardants (FRs) goes to novel efficient halogen-free materials, due to the ban of several halogenated FRs. Among the most promising alternatives are phosphorus-based FRs, and of those, polymeric materials with complex shape have been recently reported. Herein, we present novel halogen-free aromatic and aliphatic hyperbranched polyphosphoesters (hbPPEs), which were synthesized by olefin Metathesis polymerization and investigated them as a FR in epoxy resins. We compare their efficiency (aliphatic vs. aromatic) and further assess the differences between the monomeric compounds and the hbPPEs. The decomposition and vaporizing behavior of a compound is an important factor in its flame-retardant behavior, but also the interaction with the pyrolyzing matrix has a significant influence on the performance. Therefore, the challenge in designing a FR is to optimize the chemical structure and its decomposition pathway to the matrix, with regards to time and temperature. This behavior becomes obvious in this study, and explains the superior gas phase activity of the aliphatic FRs.
KW - Phosphorus
KW - Metathesis
KW - Dendritic
KW - Cone calorimeter
KW - Fire test
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494535
DO - https://doi.org/10.3390/molecules24213901
SN - 1420-3049
VL - 24
IS - 21
SP - 3901
PB - MDPI
AN - OPUS4-49453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lenz, J.
A1 - Pospiech, D.
A1 - Paven, M.
A1 - Albach, R. W.
A1 - Günther, Martin
A1 - Schartel, Bernhard
A1 - Voit, B.
T1 - Improving the Flame Retardance of Polyisocyanurate Foams by Dibenzo[d,f][1,3,2]dioxaphosphepine 6-Oxide-Containing Additives
N2 - A series of new flame retardants (FR) based on dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide (BPPO) incorporating acrylates and benzoquinone were developed previously. In this study, we examine the fire behavior of the new flame retardants in polyisocyanurate (PIR) foams. The foam characteristics, thermal decomposition, and fire behavior are investigated. The fire properties of the foams containing BPPO-based derivatives were found to depend on the chemical structure of the substituents. We also compare our results to state-of-the-art non-halogenated FR such as triphenylphosphate and chemically similar phosphinate, i.e. 9,10-dihydro-9-oxa-10- phosphaphenanthrene-10-oxide (DOPO), based derivatives to discuss the role of the phosphorus oxidation state.
KW - Polyisocyanurate
KW - Dibenzo[d,f][1,3,2]dioxaphosphepine 6-oxide
KW - Phospha-Michael addition
KW - Flame retardant
KW - Foams
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-485590
DO - https://doi.org/10.3390/polym11081242
SN - 2073-4360
VL - 11
IS - 8
SP - Article 1242
PB - MDPI
AN - OPUS4-48559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markwart, Jens C.
A1 - Battig, Alexander
A1 - Zimmermann, Lisa
A1 - Wagner, Martin
A1 - Fischer, Jochen
A1 - Schartel, Bernhard
A1 - Wurm, Frederik R.
T1 - Systematically controlled decomposition mechanism in phosphorus flame retardants by precise molecular architecture: P−O vs P−N
N2 - Flame retardants (FR) are inevitable additives to many plastics. Halogenated organics are effective FRs but are controversially discussed due to the release of toxic gases during a fire or their persistence if landfilled. Phosphorus-containing compounds are effective alternatives to halogenated FRs and have potential lower toxicity and degradability. In addition, nitrogencontaining additives were reported to induce synergistic effects with phosphorus-based FRs. However, no systematic study of the gradual variation on a single phosphorus FR containing both P−O and P−N moieties and their comparison to the respective blends of phosphates and phosphoramides was reported. This study developed general design principles for P−O- and P−N-based FRs and will help to design effective FRs for various polymers. We synthesized a library of phosphorus FRs that only differ in their P-binding pattern from each other and studied their decomposition mechanism in epoxy resins. Systematic control over the decomposition pathways of phosphate (PO(OR)3), phosphoramidate (PO(OR)2(NHR)), phosphorodiamidate (PO(OR)(NHR)2), phosphoramide (PO(NHR)3), and their blends was identified, for example, by reducing cis-elimination and the formation of P−N-rich char with increasing nitrogen content in the P-binding sphere. Our FR epoxy resins can compete with commercial FRs in most cases, but we proved that the blending of esters and amides outperformed the single molecule amidates/diamidates due to distinctively different decomposition mechanisms acting synergistically when blended.
KW - Phosphorus
KW - Flame retardants
KW - Epoxies
KW - Mechanistic study
KW - Toxicity
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481549
DO - https://doi.org/10.1021/acsapm.9b00129
SN - 2637-6105
VL - 1
IS - 5
SP - 1118
EP - 1128
PB - ACS
AN - OPUS4-48154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markwart, J. C.
A1 - Battig, Alexander
A1 - Kuckhoff, T.
A1 - Schartel, Bernhard
A1 - Wurm, F. R.
T1 - First phosphorus AB2 monomer for flame-retardant hyperbranched polyphosphoesters: AB2vs. A2 + B3
N2 - Branched polymers are an important class of polymers with a high number of terminal groups, lower viscosity compared to their linear analogs and higher miscibility, which makes them especially interesting for flame retardant applications, where the flame retardants (FR) are blended with another polymer matrix. Hyperbranched polyphosphoesters (hbPPEs) are gaining more and more interest in the field of flame retardancy, as low molar mass FRs often have the disadvantage of blooming out or leaching, which is not desired in consumer products. Here, we present the first phosphorus-based AB2 monomer for the synthesis of hbPPEs and assess its flame-retardant performance in an epoxy resin compared to a hbPPE synthesized by an A2 + B3 approach. The hbPPE synthesized from an AB2 monomer exhibited a slightly higher performance compared to a similar hbPPE, which was prepared by A2 + B3 polyaddition, probably due to its higher phosphorus content.
KW - Polyphosphoester
KW - Hyperbranched
KW - Flame retardant
KW - Synthesis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-497570
DO - https://doi.org/10.1039/c9py01156k
SN - 1759-9962
VL - 10
IS - 43
SP - 5920
EP - 5930
PB - RSC
AN - OPUS4-49757
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, Sebastian
A1 - Klack, Patrick
A1 - Bahr, Horst
A1 - Schartel, Bernhard
T1 - Assessing the fire behavior of woods modified by N-methylol crosslinking, thermal treatment, and acetylation
N2 - Wood products are often treated by different techniques to improve their longevity when used as building materials. Most of the time, the goal is to increase their resistance to weathering effects, deformations in material dimensions or biotic decomposition. These wood treatment techniques have a significant impact on pyrolysis and burning behavior. The general effects of three different common wood treatments on flame retardancy were investigated by comparing treated woods with their untreated counterparts and with other kinds of wood. While the acetylation of beech leads to a slightly increased fire hazard, the thermal treatment of wood and crosslinking of cellulose microfibrils dimethyloldihydroxy-ethyleneurea show a limited flame retarding effect. Switching to woods with a higher lignin content, and thus higher char yield, however, results in a more pronounced improvement in flame retardancy performance. This article delivers a comprehensive and balanced assessment of the general impact of different wood modifications on the fire behavior. Further, it is a valuable benchmark for assessing the flame retardancy effect of other wood modifications.
KW - Acetylation
KW - Cone claorimeter
KW - DMDHEU
KW - Heat of combustion
KW - Thermal treatment
KW - Wood modification
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-507397
DO - https://doi.org/10.1002/fam.2809
SN - 1099-1018
SN - 0308-0501
VL - 44
IS - 4
SP - 530
EP - 539
PB - Wiley Online Libary
AN - OPUS4-50739
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tahir, Warisha
A1 - Liberra, Eric
A1 - Khalil, Islam E.
A1 - Das, Prasenjit
A1 - Prinz, Carsten
A1 - Emmerling, Franziska
A1 - Schmidt, Johannes
A1 - Bergmann, Arno
A1 - Cuenya, Beatriz Roldan
A1 - Thomas, Arne
T1 - Cu2O@COF core–shell catalyst for electrochemical CO2 reduction
N2 - The electrochemical reduction of CO2 (CO2RR) to C2+ products offers a sustainable approach for carbon utilization and the production of valuable chemicals. Cu2O nanocubes (NCs) have emerged as effective electrocatalysts for the formation of C2+ products. In this study, we applied a coating of Cu2O NCs with robust covalent organic framework (COF) layers prepared by multicomponent reactions. Compact layers of COFs are formed, which, due to their porosity, allow full accessibility of the Cu2O catalytic surfaces to CO2 molecules. Furthermore, the thickness and chemical functionality of the COF layers can be continuously varied by changing the type and quantity of monomers used to cover the Cu2O NCs. Electrocatalytic measurements demonstrate that these hybrid core–shell Cu@COF systems remain active in CO2 reduction, achieving good current density and faradaic efficiency, while maintaining selectivity for the desired CO2 reduction products. Additionally, the COF shell provides remarkable stability to the system under electrochemical conditions.
KW - Electrochemical CO2 reduction
KW - Copper(I) oxide
KW - Nanocubes
KW - COF
KW - Core shell
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659177
DO - https://doi.org/10.1039/d5ta09283c
SN - 2050-7488
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
CY - London [u.a.]
AN - OPUS4-65917
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shaanika, Sam
A1 - Böllinghaus, Thomas
A1 - Sobol, Oded
A1 - Alweendo, Thomas
A1 - Krafft, Eike
A1 - Ravi, Sathish
T1 - Burst tests of cold drawn and heat treated austenitic stainless steel (316L) tubes charged in pressurized hydrogen
N2 - Global decarbonization targets are driving expansion of green hydrogen infrastructure, yet high-pressure hydrogen exposure can degrade the mechanical performance of critical stainless-steel components, typically made of the common steel 316L. This study evaluates the strength and fracture behavior of both cold-drawn and heat-treated 316L austenitic stainless-steel tubular specimens fabricated from 1/2″ (12.7 mm) and 3/8″ (9.53 mm) tube after gaseous high-pressure pre-charging with wall thickness 0.5 mm. Hydrogen concentration in the range between 76 and 100 ppm was measured in precharged sample in both states and the recorded quantity of 2–5 ppm in the non-precharged specimen. Hydrostatic burst tests at ambient tem perature were carried out with precharged specimens and revealed an increase in burst pressure for both material states, as compared to non-precharged specimens as a reference. In addition, fractographic analysis by scanning electron microscopy has identified deeper dimples and wider microvoids in hydrogen-precharged specimens, indicating also some softening of the material in the cold-drawn as well as in the heat-treated state. As the time to failure also increased, it is anticipated that the hydrogen introduced in the specimens caused a respective increase in both, ductility in terms of the straining and deformation capacity, as well as an increase in strength. For engineering applications, the findings indicate some beneficial effect that, despite exposure to extreme hydrogen conditions, 316L tubes retain, and even modestly enhance, their structural integrity, supporting a safe deployment in green hydrogen transport and storage systems, at least at ambient temperature.
KW - Green hydrogen technologies
KW - Hydrogen cracking avoidance
KW - Strengthening-softening effects
KW - Heat treatment
KW - Austenitic stainless steel
KW - Burst pressure
KW - Joule heating
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659332
DO - https://doi.org/10.1007/s40194-026-02448-5
SN - 1878-6669
SP - 1
EP - 13
PB - Springer
CY - Berlin
AN - OPUS4-65933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cameli Manzo, Riccardo
A1 - Baran, Volodymyr
A1 - Shevchenko, Artem
A1 - Sleptsova, Anastasia
A1 - Hoffmann, Frank
A1 - Stolar, Tomislav
A1 - Dinnebier, Robert E.
A1 - Etter, Martin
T1 - N-Methylated Nucleobases Crystal Structures and π-π Stacking Interactions
N2 - Solid-state studies evaluating intermolecular geometries in methylated nucleobases are not extensively explored. In the course of the present study, we have solved the crystal structures of 1-, 3- and 7-methylated adenines and guanines, including the monohydrate and sesquihydrate forms of 3-methyladenine and 3-methylguanine, respectively, by means of single-crystal X-ray diffraction and synchrotron/laboratory X-ray powder diffraction (XRPD). In situ high temperature XRPD experiments, coupled with differential thermal analysis/thermogravimetry (DTA/TG) measurements, allowed for monitoring crystallographic changes after water removal of N3-methylated compounds, and the discovery of a high temperature polymorph in the case of 3-methyladenine. Our findings indicate that H-bonding schemes describe ribbon planar motifs of molecules in the majority of cases, or linear double-bonded strands of molecules in a few cases. π-π stacking interactions were compared with existing findings of theoretical calculations and existing crystallographic data, showing how N-methylated purine bases follow the trend predicted by Hunter and Sanders, 1990. The present study provides the first systematic experimental insights into the solid state of the presented compounds.
KW - Solid state
KW - Synchrotron PXRD
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659188
DO - https://doi.org/10.3390/molecules31081326
VL - 31
IS - 8
SP - 1
EP - 30
PB - MDPI
CY - Basel
AN - OPUS4-65918
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andrés Arcones, Daniel
A1 - Weiser, M.
A1 - Koutsourelakis, P-S.
A1 - Unger, Jörg F.
T1 - Embedded Model Form Uncertainty Quantification with Measurement Noise for Bayesian Model Calibration
N2 - A key factor in ensuring the accuracy of computer simulations that model physical systems is the proper calibration of their parameters based on real-world observations or experimental data. Bayesian methods provide a robust framework for quantifying and propagating the uncertainties that inevitably arise. Nevertheless, they produce predictions unable to represent the observed datapoints when paired with inexact models. Additionally, the quantified uncertainties of these overconfident models cannot be propagated to other Quantities of Interest (QoIs) reliably. A promising solution involves embedding a model inadequacy term in the inference parameters, allowing the quantified model form uncertainty to influence non-observed QoIs. In this work, we revisit this embedded formulation and analyze how different likelihood constructions affect the inference of model form uncertainty, particularly under the presence of prescribed measurement noise and unavoidable model discrepancies. Two additional likelihood formulations, the global moment-matching and relative global moment-matching likelihoods, are introduced to explore alternative ways of representing the residual distribution. The behavior of these likelihoods is examined alongside existing formulations to show how different treatments of measurement noise and discrepancies shape the inferred parameter posteriors, and thereby affect the uncertainty ultimately propagated to the QoIs. Particular attention is given to how the uncertainty associated with the model inadequacy term propagates to the QoIs for the posteriors obtained from different likelihood formulations, enabling a more comprehensive statistical analysis of the prediction’s reliability. Finally, the proposed approach is applied to estimate the uncertainty in the predicted heat flux from a transient thermal simulation using temperature observations
KW - Bayesian Inference
KW - Model from uncertainty
KW - Model updating
KW - Noise
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658995
DO - https://doi.org/10.1017/dce.2025.10035
VL - 7
SP - 1
EP - 45
PB - Cambrigde University Press
AN - OPUS4-65899
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huo, Wenjie
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, Katinka
T1 - Detection of solidification crack formation in laser beam welding videos of sheet metal using neural networks
N2 - AbstractLaser beam welding has become widely applied in many industrial fields in recent years. Solidification cracks remain one of the most common welding faults that can prevent a safe welded joint. In civil engineering, convolutional neural networks (CNNs) have been successfully used to detect cracks in roads and buildings by analysing images of the constructed objects. These cracks are found in static objects, whereas the generation of a welding crack is a dynamic process. Detecting the formation of cracks as early as possible is greatly important to ensure high welding quality. In this study, two end-to-end models based on long short-term memory and three-dimensional convolutional networks (3D-CNN) are proposed for automatic crack formation detection. To achieve maximum accuracy with minimal computational complexity, we progressively modify the model to find the optimal structure. The controlled tensile weldability test is conducted to generate long videos used for training and testing. The performance of the proposed models is compared with the classical neural network ResNet-18, which has been proven to be a good transfer learning model for crack detection. The results show that our models can detect the start time of crack formation earlier, while ResNet-18 only detects cracks during the propagation stage.
KW - Artificial Intelligence
KW - Software
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586116
DO - https://doi.org/10.1007/s00521-023-09004-y
SN - 0941-0643
VL - 35
IS - 34
SP - 24315
EP - 24332
PB - Springer Science and Business Media LLC
AN - OPUS4-58611
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Javaheri, E.
A1 - Kumala, V.
A1 - Javaheri, A.
A1 - Rawassizadeh, R.
A1 - Lubritz, J.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Quantifying Mechanical Properties of Automotive Steels with Deep Learing Based Computer Vision Algorithms
N2 - This paper demonstrates that the instrumented indentation test (IIT), together with a trained artificial neural network (ANN), has the capability to characterize the mechanical properties of the local parts of a welded steel structure such as a weld nugget or heat affected zone.
Aside from force-indentation depth curves generated from the IIT, the profile of the indented surface deformed after the indentation test also has a strong correlation with the materials’ plastic behavior. The profile of the indented surface was used as the training dataset to design an ANN to determine the material parameters of the welded zones. The deformation of the indented surface in three dimensions shown in images were analyzed with the computer vision algorithms and the obtained data were employed to train the ANN for the characterization of the mechanical properties. Moreover, this method was applied to the images taken with a simple light microscope from the surface of a specimen. Therefore, it is possible to quantify the mechanical properties of the automotive steels with the four independent methods: (1) force-indentation depth curve; (2) profile of the indented surface; (3) analyzing of the 3D-measurement image; and (4) evaluation of the images taken by a simple light microscope. The results show that there is a very good Agreement between the material parameters obtained from the trained ANN and the experimental uniaxial tensile test. The results present that the mechanical properties of an unknown steel can be determined by only analyzing the images taken from its surface after pushing a simple indenter into its surface.
KW - Deep learning
KW - Computer vision
KW - Artificial neural network
KW - Clustering
KW - Mechanical properties
KW - High strength steels
KW - Instumented indentation test
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-503038
DO - https://doi.org/10.3390/met10020163
VL - 10
IS - 2
SP - 163
PB - MDPI
AN - OPUS4-50303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Javaheri, E.
A1 - Lubritz, J.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Mechanical Properties Characterization of Welded Automotive Steels
N2 - Among the various welding technologies, resistance spot welding (RSW) and laser beam welding (LBW) play a significant role as joining methods for the automobile industry. The application of RSW and LBW for the automotive body alters the microstructure in the welded areas. It is necessary to identify the mechanical properties of the welded material to be able to make a reliable statement about the material behavior and the strength of welded components. This study develops a method by which to determine the mechanical properties for the weldment of RSW and LBW for two dual phase (DP) steels, DP600 and DP1000, which are commonly used for the automotive bodies. The mechanical properties of the resistance spot weldment were obtained by performing tensile tests on the notched tensile specimen to cause an elongation of the notched and welded area in order to investigate its properties. In order to determine the mechanical properties of the laser beam weldment, indentation tests were performed on the welded material to calculate its force-penetration depth-curve. Inverse numerical simulation was used to simulate the indentation tests to determine and verify the parameters of a nonlinear isotropic material model for the weldment of LBW. Furthermore, using this method, the parameters for the material model of RSW were verified. The material parameters and microstructure of the weldment of RSW and LBW are compared and discussed. The results show that the novel method introduced in this work is a valid approach to determine the mechanical properties of welded high-strength steel structures. In addition, it can be seen that LBW and RSW lead to a reduction in ductility and an increase in the amount of yield and tensile strength of both DP600 and DP1000.
KW - Mechanical property
KW - Laser beam welding
KW - Dual phase steel
KW - Resistance spot welding
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502269
DO - https://doi.org/10.3390/met10010001
VL - 10
IS - 1
SP - 1
EP - 20
PB - MDPI
AN - OPUS4-50226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Porosity prediction in laser beam welding with a multimodal physics-informed machine learning framework
N2 - Laser beam welding (LBW) of metallic components is a knowledge‑intensive manufacturing process whose quality depends on the complex multi‑physics. However, its engineering application is often hindered by the occurrence of porosity defects. Achieving a thorough understanding and reliable prediction of porosity defects remains difficult because it demands robust representation and reasoning over nonlinear and hard‑to‑observe physical information. In this study, we propose an integrated multimodal physics-informed machine learning (PIML) framework with the help of multi-physical modelling and experimental data to predict the porosity defects in laser beam welding of aluminum alloys. The whole framework contains a multimodal PIML model for predicting the porosity ratio and an ML-based estimator for relevant physical information. By utilizing the scalar welding parameters and high-dimensional physical information (probability of keyhole collapses, cumulative existing time of collapses, and molten pool geometry) as inputs, the multimodal PIML model shows great superiority in predicting the porosity ratio, with a reduction of the mean square error by 45%, compared with the ML model trained only with welding parameters. The ML-based estimator constructed with an encoder‐decoder architecture can accurately reproduce the critical physical information within a timeframe of seconds. By integrating these two ML models, the proposed framework advances engineering informatics by offering a scalable, physics-knowledge‑centric solution for fast and accurate porosity prediction in LBW manufacturing.
KW - Laser beam welding
KW - Porosity defect
KW - Physics-informed machine learning
KW - Multimodal model
KW - Simulation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657589
DO - https://doi.org/10.1016/j.aei.2026.104611
SN - 1474-0346
VL - 74
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-65758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Akyel, Fatma
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Brunner-Schwer, Christian
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of heat input on cooling rates and mechanical properties of laser hybrid welded thick structural steels
N2 - Laser hybrid welding presents several challenges when used to weld thick steels. A typical weld is divided into the arcdominated and laser-dominated zone. These zones lead to variations in the mechanical properties of the weld. The laserdominated zone is of particular importance regarding mechanical properties, notably Charpy impact toughness, due to the high cooling rates and the absence of filler wire. The low heat input of the laser can lead to martensitic microstructure causing hardening and deterioration of impact toughness. The high heat input of the arc can lead to grain coarsening and even loss of impact toughness. This study examines the influence of heat input on the cooling rates, microstructure and mechanical properties of single-pass laser hybrid welded steels of S355J2 and EH36 with thicknesses up to 30 mm. The experiments were performed with a 20-kW fibre laser and a contactless electromagnetic weld backing in the butt-joint configuration in 1G welding position. The cooling time was measured in three different locations near the fusion lines corresponding to different heights of the seam using a special configuration with pyrometers, collimators and optical fibres. The test specimens for the Charpy impact testing and tensile testing were extracted in three different depths. The experiments indicated that a heat input of 1.6 kJ/mm–2 kJ/mm, 2 kJ/mm–2.4 kJ/mm and 3.7 kJ/mm were recommended when single-pass laser hybrid welding of 20-, 25-, and 30-mm-thick structural steels regarding the minimum requirements of the mechanical properties, respectively.
KW - Laser hybrid welding
KW - Heat input
KW - Mechanical properties
KW - Charpy impact toughness
KW - Cooling rate
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625282
DO - https://doi.org/10.1007/s40194-025-01924-8
SN - 1878-6669
SP - 1
EP - 15
PB - Springer
CY - United Kingdom
AN - OPUS4-62528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marquardt, R.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Functionally graded material for improved wear resistance manufactured by directed energy deposition
N2 - Protecting components against wear and corrosion is a common way to improve their lifetime. This can be achieved by coating them with a hardfacing material. Common coatings consist of materials such as tungsten carbide or cobalt-chromium alloys, also known as Stellite. Hardfacing materials can be deposited by welding methods like plasma welding or laser cladding. The discrete change of the base material to the hardfacing layer can lead to cracks and chipping. Studies showed a reduced risk of cracking when a functionally graded material is used to create a smooth transition between the base and the hardfacing. Gradings from austenitic steel to cobalt-chromium alloys are already known in the literature. However, there is no knowledge about austenitic- ferritic duplex steels as base material. Therefore, this study aims to demonstrate the feasibility of a functionally graded material from duplex steel to cobalt-chromium alloy with a new approach. By using powder-based directed energy deposition, a graded material with smooth material transition is manufactured additively. Cracking and porosity are examined through metallography. Microhardness measurements as well as the analysis of the chemical composition by energy dispersive X-ray spectroscopy and X-ray fluorescence are used to validate the build-up strategy.
KW - Additive manufacturing
KW - Functionally graded material
KW - Functionally graded additive manufacturing
KW - Directed energy deposition
KW - Laser metal deposition
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621683
DO - https://doi.org/10.1007/s40964-024-00879-4
SP - 1
EP - 6
PB - Springer Science and Business Media LLC
AN - OPUS4-62168
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hartwig, Philipp
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Scheunemann, Lisa
A1 - Schröder, Jörg
A1 - Rethmeier, Michael
T1 - A Physically Motivated Heat Source Model for Laser Beam Welding
N2 - In this contribution, we present a physically motivated heat source model for the numerical modeling of laser beam welding processes. Since the calibration of existing heat source models, such as the conic or Goldak model, is difficult, the representation of the heat source using so-called Lamé curves has been established, relying on prior Computational Fluid Dynamics (CFD) simulations.
Lamé curves, which describe the melting isotherm, are used in a subsequent finite-element (FE) simulation to define a moving Dirichlet boundary condition, which prescribes a constant temperature in the melt pool. As an alternative to this approach, we developed a physically motivated heat source model, which prescribes the heat input as a body load directly. The new model also relies on prior CFD simulations to identify the melting isotherm. We demonstrate numerical results of the new heat source model on boundary-value problems from the field of laser beam welding and compare it with the prior CFD simulation and the results of the Lamé curve model and experimental data.
KW - Welding simulation
KW - Heat source models
KW - Laser beam welding
KW - Thermal analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600899
DO - https://doi.org/10.3390/met14040430
VL - 14
IS - 4
SP - 1
EP - 26
PB - MDPI
CY - Basel
AN - OPUS4-60089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Epishin, A.
A1 - Fedelich, Bernard
A1 - Finn, Monika
A1 - Künecke, Georgia
A1 - Rehmer, Birgit
A1 - Nolze, Gert
A1 - Leistner, C.
A1 - Petrushin, N.
A1 - Svetlov, I.
T1 - Investigation of Elastic Properties of the Single-Crystal Nickel-Base Superalloy CMSX-4 in the Temperature Interval between Room Temperature and 1300 °C
N2 - The elastic properties of the single-crystal nickel-base superalloy CMSX-4 used as a blade material in gas turbines were investigated by the sonic resonance method in the temperature interval between room temperature and 1300 °C. Elastic constants at such high temperatures are needed to model the mechanical behavior of blade material during manufacturing (hot isostatic pressing) as well as during technical accidents which may happen in service (overheating). High reliability of the results was achieved using specimens of different crystallographic orientations, exciting various vibration modes as well as precise measurement of the material density and thermal Expansion required for modeling the resonance frequencies by finite element method. Combining the results measured in this work and literature data the elastic constants of the gamma and gamma' phases were predicted.
This prediction was supported by measurement of the temperature dependence of the gamma'fraction.
All data obtained in this work are given in numerical or analytical forms and can be easily used for different scientific and engineering calculations.
KW - Nickel-base superalloys
KW - Single-crystals
KW - Characterization
KW - Elastic constants
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520972
DO - https://doi.org/10.3390/cryst11020152
VL - 11
IS - 2
SP - 152
PB - MDPI
AN - OPUS4-52097
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Rethmeier, Michael
A1 - Gumenyuk, Andrey
T1 - Influence of edge‑deposited layers on mechanical and corrosion properties of laser beam welds of 15 mm thick AISI 2205 duplex stainless steel
N2 - AISI 2205 duplex stainless steel is used in a variety of industries, including the chemical and petrochemical industries. This is due to its high tensile strength combined with good ductility and corrosion resistance. However, in laser beam welding, these properties are negatively afected by the high cooling rates typical of the welding process. The resulting higher ferrrite content in the weld metal than in the base material leads to a reduction in the ductility and corrosion resistance of the welded joint. To overcome this problem, in this study, thick plates were coated by direct energy deposition (DED) prior to laser beam welding, whereas a duplex powder mixture containing a higher nickel concentration was used as a coating material. To improve the weld quality for the proposed two-step process, a method of additional material deposition instead of conventional tack weld was investigated. The resulting welded joints showed a well-balanced austenite to ferrite ratio and their properties and microstructure were verifed by metallographic analysis, electron backscatter difraction and Charpy impact testing. Using the standard ASTM G48 test method, it was found that the corrosion resistance of the welds was improved by a factor of four in average compared to the conventionally welded joints. The resulting properties, such as good ductility and corrosion resistance, of the welds with pre-coated edges showed good agreement with those of the base metal and confrmed the proposed two-step process as a promising alternative to the conventional approaches for welding thick duplex stainless steel plates.
KW - Laser metal deposition
KW - Laser beam welding
KW - Duplex steels
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581731
UR - https://rdcu.be/dlb6E
DO - https://doi.org/10.1007/s40194-023-01567-7
SN - 0043-2288
SP - 1
EP - 12
PB - Springer
AN - OPUS4-58173
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of the weld pool geometry on solidification cracking in partial penetration high power laser beam welding
N2 - Solidification cracking is still a serious problem in laser beam welding, especially in the welding of thick-walled plates. The influence of weld pool geometry on solidification cracking in partial penetration welding of thick plates is investigated within scope of this study. Therefore, a specific experimental setup of steel and quartz glass in butt configuration and on the side with high-speed camera were used to record the weld pool shape. In addition, the influence of laser inclination angle on the weld pool geometry and on solidification crack formation was investigated. The results show a bulge in the weld pool root, which is separated from an upper region by a necking region. This leads to a case where there are three different longitudinal region lengths with different solidification zones. This temporal sequence of solidification strongly promotes the formation of solidification cracks in the weld root.
T2 - 12th CIRP Conference on photonic technologies (LANE 2022)
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser beam welding
KW - Partial penetration
KW - Weld pool shape
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563940
DO - https://doi.org/10.1016/j.procir.2022.08.174
VL - 111
SP - 397
EP - 400
PB - Elsevier B.V.
AN - OPUS4-56394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schröder, Simon Alexander
A1 - Weigel, Sandra
A1 - Nytus, N.
A1 - Dominik, J.
A1 - Radenberg, M.
A1 - Schwettmann, K.
A1 - Cheng, M.
A1 - Stephan, D.
ED - Eberhardsteiner, L.
ED - Hofko, B.
ED - Blab, R.
T1 - Postcarbone road: Limits and possibilities of cyclic bitumen rejuvenation
N2 - In road construction, the reuse of reclaimed asphalt depends on the addition of large quantities of fresh binder. Bio-based rejuvenators can represent a sustainable alternative to this, but their performance concerning multiple reuses has yet to be investigated. For this study, fresh 50/70 bitumen was subjected to up to four ageing and rejuvenation cycles using eight commercially available rejuvenators (five bio- and three petroleum-based). The rheological and chemical evaluation of the raw materials and resulting products was carried out using a dynamic shear rheometer and Fourier transform infrared spectrometer. Through examina-tion of the infrared spectra, the rejuvenators were divided into three groups based on similar chemical compo-sition. Further, evaluated optimum dosage quantities required to rejuvenate aged binder indicate that bio-based rejuvenators are more resource-efficient than their petrol-based counterparts. Finally, a most promising bio-based rejuvenator candidate was found, allowing up to four reuse cycles.
T2 - 4th International Conference on Advances in Materials and Pavement Performance Prediction (AM3P 2025)
CY - Vienna, Austria
DA - 07.05.2025
KW - Cyclic bitumen rejuvenation
KW - Postcarbone road
KW - Asphalt
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659039
DO - https://doi.org/10.34726/9259
SP - 279
EP - 282
PB - TU Wien, E230-03 Road Engineering
AN - OPUS4-65903
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Fasselt, Janek Maria
A1 - Klötzer-Freese, Christian
A1 - Kruse, Tobias
A1 - Kleba-Ehrhardt, Rafael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Recycling nickel aluminium bronze grinding chips to feedstock for directed energy deposition via impact whirl milling: Investigation on processability, microstructure and mechanical properties
N2 - During the production of ship propellers, considerable quantities of grinding chips from nickel aluminium bronze areproduced. This paper examines the mechanical comminution of such chips via impact whirl milling and the utilization of twochip-powder batches as feedstock for a laser-based directed energy deposition process. The materials are characterized viadigital image analysis, standardized flowability tests, scanning electron microscopy and energy dispersive X-ray spectroscopyand are compared to conventional, gas atomized powder. The specimens deposited via directed energy deposition areanalyzed for density, hardness and microstructure and tensile properties for vertical and horizontal build up directions arecompared. At elevated mill rotation speeds, the comminution with impact whirl milling produced rounded particles, favorableflow properties and particle size distribution, making them suitable to deposit additive specimens. The microstructureexhibited characteristic martensitic phases due to the high cooling rates of the additive manufacturing process. The presenceof ceramic inclusions was observed in both the powder and on the tensile fracture surfaces, partly impairing the mechanicalproperties. However, specimens in the vertical build-up direction (Z) showed competitive tensile results, with 775 MPa intensile strength, 455 MPa in yield strength and 12.6 % elongation at break. The findings of this study indicate that recyclingof machining chips to additive manufacturing feedstock can be a viable option for reducing material costs and environmentalimpact.
KW - Nickel aluminium bronze
KW - Grinding chips
KW - Recycling
KW - Directed energy deposition
KW - Material characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651214
DO - https://doi.org/10.1016/j.addma.2025.104804
SN - 2214-8604
VL - 105
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Petrat, T.
A1 - Graf, B.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
ED - Schmidt, M.
ED - Vollertsen, F.
ED - Arnold, C. B.
T1 - Laser metal deposition as repair technology for a gas turbine burner made of Inconel 718
N2 - Maintenance, repair and overhaul of components are of increasing interest for parts of high complexity and expensive manufacturing costs. In this paper a production process for laser metal deposition is presented, and used to repair a gas turbine burner of Inconel 718. Different parameters for defined track geometries were determined to attain a near net shape deposition with consistent build-up rate for changing wall thicknesses over the manufacturing process. Spot diameter, powder feed rate, welding velocity and laser power were changed as main parameters for a different track size. An optimal overlap rate for a constant layer height was used to calculate the best track size for a fitting layer width similar to the part dimension. Deviations in width and height over the whole build-up process were detected and customized build-up strategies for the 3D sequences were designed. The results show the possibility of a near net shape repair by using different track geometries with laser metal deposition.
T2 - LANE - 9 International Conference on Photonic Technologies
CY - Fürth, Germany
DA - 19.09.2016
KW - Laser metal deposition
KW - Inconel 718
KW - Additive manufacturing
KW - Maintenance
KW - Repair and overhaul
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-376723
UR - http://ac.els-cdn.com/S1875389216301857/1-s2.0-S1875389216301857-main.pdf?_tid=ed1d75de-84a2-11e6-af94-00000aab0f6c&acdnat=1474974777_4917d753cb3d316c4b000ba0760778b5
DO - https://doi.org/10.1016/j.phpro.2016.08.078
SN - 1875-3892
VL - 83
SP - 761
EP - 768
PB - Elservier
AN - OPUS4-37672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neubert, Sebastian
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Experimental determination of TRIP parameter K for mild- and high strength low alloy steels and a super martensitic filler material
N2 - A combined experimental numerical approach is applied to determine the transformation induced plasticity (TRIP)-parameter K for different strength low-alloy steels of grade S355J2+N and S960QL as well as the super martensitic filler CN13-4-IG containing 13 wt% chromium and 4 wt% nickel. The thermo-physical analyses were conducted using a Gleeble® 3500 facility. The thermal histories of the specimens to be tested were extracted from corresponding simulations of a real gas metal arc weldment. In contrast to common TRIP-experiments which are based on complex specimens a simple flat specimen was utilized together with an engineering evaluation method. The evaluation method was validated with literature values for the TRIP-parameter. It could be shown that the proposed approach enables a correct description of the TRIP behavior.
KW - Transformation induced plasticity (TRIP)
KW - Phase transformation
KW - High-strength low-alloy steel
KW - Super martensitic filler material
KW - Thermo physical simulation
KW - Gleeble experiments
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367297
DO - https://doi.org/10.1186/s40064-016-2474-0
VL - 5
IS - 575
SP - Paper 754, 1
EP - 16
PB - SpringerPlus
AN - OPUS4-36729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Bakir, Nasim
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Weld pool shape observation in high power laser beam welding
N2 - The geometry of the melt pool in laser beam welding plays a major role to understand the dynamics of the melt and its solidification behavior. In this study, a butt configuration of 15 mm thick structural steel and transparent quartz glass was used to observe the weld pool geometry by means of high-speed camera and an infrared camera recording. The observations show that the dimensions of the weld pool vary depending on the depth. The areas close to the weld pool surface take a teardrop-shape. A bulge-region and its temporal evolution were observed approximately in the middle of the depth of the weld pool. Additionally, a 3D transient thermal-fluid numerical simulation was performed to obtain the weld pool shape and to understand the formation mechanism of the observed bulging effect. The model takes into account the local temperature field, the effects of phase transition, thermo-capillary convection, natural convection and temperature-dependent material properties up to evaporation temperature. The numerical results showed good accordance and were furthermore used to improve the understanding of the experimentally observed bulging effect.
T2 - LANE Conference 2018
CY - Fürth, Germany
DA - 03.09.2018
KW - High power laser beam welding
KW - Weld pool shape
KW - Bulging
KW - Numerical process simulation
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458759
DO - https://doi.org/10.1016/j.procir.2018.08.043
SN - 2212-8271
VL - 74
SP - 683
EP - 686
PB - Elsevier Ltd.
CY - Amsterdam [u.a.]
AN - OPUS4-45875
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ö.
A1 - Fritzsche, André
A1 - Avilov, V.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Study of gap and misalignment tolerances at hybrid laser arc welding of thick-walled steel with electromagnetic weld pool support system
N2 - The hybrid laser arc welding (HLAW) process provides many advantages such as improved gap bridgeability, deep penetration and misalignment of edges, that is why the process is used increasingly in industrial applications e.g. shipbuilding, power plant industry and line-pipe manufacturing. The obvious encountered problem for single pass welding in flat position is the gravity drop-out at low welding velocities. With the usage of an electromagnetic weld pool support system, which is based on generating Lorentz forces within the weld pool, wide seams followed by reduced welding velocities could be achieved in this study leading to the realization of a gap bridgeability up to 1 mm, misalignment of edges up to 2 mm and a single pass weld up to 28 mm thickness with a 20-kW fibre laser. These developments expand the boundaries of the HLAW process for different industrial applications. As a result, less accurate preparation of the edges would be sufficient, which saves time for manufacturing.
KW - Hybrid laser-arc welding
KW - Electromagnetic weld pool support system
KW - Thick-walled steel
KW - Gap bridgeability
KW - Single pass welding
KW - Misalignment of edges
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468263
DO - https://doi.org/10.1016/j.procir.2018.08.016
SN - 2212-8271
VL - 74
SP - 757
EP - 760
PB - Elsevier
AN - OPUS4-46826
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Pavlov, V.
A1 - Zavjalov, S.
A1 - Volvenko, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Novel metrology to determine the critical strain conditions required for solidification cracking during laser welding of thin sheets
N2 - This paper represents the results for proposed optical flow method based on the Lucas-Kanade (LK) algorithm applied to two different problems. The following observations can be made:
- The estimated strain and displacement for conducted tensile test are generally very close to those measured with conventional DIC-technique.
- The LK technique allows measurement of strain or displacement without special selection of a region of interest.
Using a novel optical measurement technique together with the optical flow algorithm, a twodimensional deformation analysis during welding was conducted. This technique is the first to provide a measurement of the full strain field locally in the immediate vicinity of the solidification front. Additionally, the described procedure of the optical measurement allows the real material-dependent values of critical strain characterizing the transition to hot cracking during laser welding processes to be determined.
T2 - Beam Technologies and Laser Application
CY - Sankt Petersburg, Russia
KW - Hot cracking test
KW - Local critical strain
KW - Solidification cracking
KW - Laser beam welding
KW - Novel metrology
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-467226
DO - https://doi.org/10.1088/1742-6596/1109/1/012047
SN - 1742-6596
VL - 1109
IS - 012047
SP - 1
EP - 9
PB - IOP Publ.
CY - Bristol
AN - OPUS4-46722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ö.
A1 - Avilov, V.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Full penetration hybrid laser arc welding of up to 28 mm thick S355 plates using electromagnetic weld pool support
N2 - The laser hybrid welding process offers many advantages regarding deep penetration, increased welding velocity and with the help of the supplied filler wire an improved bridgeability to gap and misalignment tolerances. High power laser systems with a power of approx. 30 kW are already available on the market. Nevertheless, multi-layer technology with an arc process is still used for welding of plates from a thickness from 20 mm. A potential cause is the process instability with increasing laser power. It is inevitable that gravity drop-out due to the high hydrostatic pressure at increasing wall thickness especially at welding in flat position and with a low welding speed. The surface tension decreases with increasing root width resulting from low welding velocities. To prevent such inadmissible defects of the seam a use of weld pool support is required. Usual weld pool support systems such as ceramic or powder supports require a mechanical detachment which is time-consuming. The electromagnetic weld pool support system described in this work shows an alternative weld pool support which works contactless. It is based on generating Lorentz forces in the weld pool due to oscillating magnetic field and induced eddy currents. This innovative technology offers single pass welds up to 28 mm in flat position and reduced welding velocity with a laser power of just 19 kW. It also leads to improved mechanical-technological properties of the seams because of the slow cooling rate. With usage of an electromagnetic weld pool support the limitation of the hybrid laser arc welding process in the thick sheet metal will be extend.
KW - Electromagnetic weld pool support
KW - Hybrid laser arc welding
KW - Thick-walled steel
KW - Single pass welding
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-468276
DO - https://doi.org/10.1088/1742-6596/1109/1/012015
SN - 1742-6596
VL - 1109
SP - 1
EP - 7
PB - IOP Publ.
AN - OPUS4-46827
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Altenburg, Simon
A1 - Maierhofer, Christiane
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
T1 - Comparison of MWIR thermography and high-speed NIR thermography in a laser metal deposition (LMD) process
N2 - Additive manufacturing (AM) offers a range of novel applications. However, the manufacturing process is complex and the production of defect-free parts with high reliability and durability is still a challenge. Thermography is a valuable tool for process surveillance, especially in metal AM processes. The high process temperatures allow one to use cameras usually operating in the visible spectral range. Here, we compare the results of measurements during the manufacturing process of a commercial laser metal deposition setup using a mid-wavelength-IR camera with those from a visual spectrum high-speed camera with band pass filter in the near-IR range.
T2 - Conference QIRT 2018
CY - Berlin, Germany
DA - 25.06.2018
KW - Additive manufacturing
KW - Laser metal deposition
KW - ProMoAM
KW - Thermography
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-454993
UR - http://www.qirt.org/archives/qirt2018/papers/p35.pdf
DO - https://doi.org/10.21611/qirt.2018.p35
SP - 1
EP - 5
PB - QIRT Council
CY - Quebec, Canada
AN - OPUS4-45499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Graf, Benjamin
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser metal deposition as repair technology for stainless steel and titanium alloys
N2 - In a repair process chain, damaged areas or cracks can be removed by milling and subsequently be reconditioned with new material deposition. The use of laser metal deposition has been investigated for this purpose. The material has been deposited into different groove shapes, using both stainless steel and Ti-6Al-4 V. The influence of welding parameters on the microstructure and the heat affected zone has been studied. The parameters have been modified in order to achieve low heat input and consequently low distortion as well as low metallurgical impact. Finally, an evaluation of the opportunities for an automatized repair process is made.
T2 - LANE 2012 - Laser Assisted net shape engineering 7
CY - Fürth, Germany
DA - 12.11.2012
KW - Laser metal deposition
KW - Laser powder cladding
KW - Repair welding
KW - Ti-6Al-4 V
KW - Stainless steel
PY - 2012
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-273066
DO - https://doi.org/10.1016/j.phpro.2012.10.051
N1 - Serientitel: Physics Procedia – Series title: Physics Procedia
VL - 39
SP - 376
EP - 381
PB - Elsevier B.V.
AN - OPUS4-27306
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jonietz, Florian
A1 - Ziegler, Mathias
A1 - Myrach, Philipp
A1 - Suwala, H.
A1 - Rethmeier, Michael
T1 - Untersuchung von Punktschweißverbindungen mit aktiver Thermografie
N2 - Widerstandspunktschweißen ist insbesondere im Automobilbau eine der wichtigsten Fügetechniken. Bislang erfolgt die Qualitätssicherung überwiegend durch stichprobenartige zerstörende Prüfung. Eine zerstörungsfreie Prüftechnik würde neben der Reduzierung der Prüfkosten auch eine Optimierung des Punktschweißverfahrens bedeuten, da prinzipiell jeder Schweißpunkt geprüft werden könnte und somit auch eine Reduzierung der Anzahl der Schweißpunkte möglich ist.
Es wird ein Verfahren vorgestellt, bei dem die Punktschweißverbindung zwischen zwei Stahlblechen optisch auf einer Blechseite mittels Laser oder Blitzlicht erwärmt wird. Die aufgeschmolzene Zone, die sogenannte Schweißlinse, stellt dabei neben der mechanischen Verbindung auch eine Wärmebrücke zwischen den beiden verschweißten Blechen dar, die bei diesem Verfahren ausgenutzt wird. Durch den verbesserten thermischen Kontakt zwischen den verschweißten Blechen an der Schweißlinse kontrastiert diese deutlich mit dem umgebenden Blechmaterial, bei dem der Wärmeübertrag zwischen den Blechen vergleichsweise gering ist. Dieser Kontrast im thermischen Verhalten kann mittels zeitabhängiger Thermografie gemessen werden.
Durch das hier vorgestellte Verfahren kann mittels aktiver Thermografie sowohl in Transmissions- als auch in Reflexionsanordnung die Größe des thermischen Kontaktes zwischen den beiden Blechen ermittelt werden, welche ein Maß für die Größe der Schweißlinse und damit für die qualitative Güte der Schweißung darstellt. Ein Vorteil des entwickelten Verfahrens ist seine Anwendbarkeit auf Bleche ohne Oberflächenbehandlung.
T2 - DACH-Jahrestagung 2015
CY - Salzburg, Austria
DA - 11.05.2015
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-343476
UR - http://www.ndt.net/?id=19068
SN - 1435-4934
VL - 21
IS - 4
SP - 1
EP - 7
PB - NDT.net
CY - Kirchwald
AN - OPUS4-34347
LA - deu
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fritzsche, André
A1 - Avilov, Vjaceslav
A1 - Gumenyuk, Andrey
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - High power laser beam welding of thick-walled ferromagnetic steels with electromagnetic weld pool support
N2 - The paper describes an experimental investigation of high power laser beam welding with an electromagnetic weld pool support for up to 20 mm thick plates made of duplex steel (AISI 2205) and mild steel (S235JR). The results of the welding tests show a successful application of this technology at ferromagnetic metals. Irregular sagging was suppressed successfully. An ac-power of less than 2 kW at oscillation frequencies between 800 Hz and 1.7 kHz is necessary for a full compasation of the hydrostatic pressure. Thus, it was demonstrated that the electromagnetic weld pool support is not only limited to non-ferromagnetic metals like austenitic steels. For future studies with duplex steel, the use of filler material has to take into account with regard to the balance of the mixed austenitic and ferritic phases.
KW - Laser beam welding
KW - Thick-walled steel
KW - Ferromagnetic steel
KW - Weld pool support
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377593
DO - https://doi.org/10.1016/j.phpro.2016.08.038
SN - 1875-3892
VL - 83
SP - 362
EP - 372
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-37759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Welding with high-power lasers: trends and developments
N2 - High-power laser beam welding became new stimuli within the last 10 years due to the availability of a new generation of high brightness multi kilowatt solid state lasers. In the welding research new approaches have been developed to establish reliable and praxis oriented welding processes meeting the demands of modern industrial applications during this time. The paper focuses on some of the current scientific and technological aspects in this research field like hybrid laser arc welding, simulation techniques, utilization of electromagnetic fields or reduced pressure environment for laser beam welding processes, which contributed to the further development of this technology or will play a crucial role in its further industrial implementation.
T2 - 9th International Conference on Photonic Technologies - LANE 2016
CY - Fürth, Germany
DA - 19.09.2016
KW - High-power Laserbeam Welding
KW - Electromagnetic Force
KW - Vacuum
KW - Simulation
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-377280
DO - https://doi.org/10.1016/j.phpro.2016.08.003
VL - 83
SP - 15
EP - 25
PB - Elsevier B.V.
CY - Berlin, Germany
AN - OPUS4-37728
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Life Cycle Assessment of Fusion Welding Processes - A Case Study of Resistance Spot Welding Versus Laser Beam Welding
N2 - The high amount of resource consumption of fusion welding processes offers the potential to reduce their environmental impact. While the driving forces are known froma qualitative perspective, the quantitative assessment of the crucial parameters is not a trivial task. Therefore, herein, a welding-specific methodology to utilize life cycle assessment as a tool for evaluating the environmental impact of fusion welding processes is presented. In this context, two welding processes, resistance spot welding and laser beam welding, are analyzed for two different use cases.
These comprise the welding of shear test specimens and a cap profile made of electrogalvanized sheets of DC 05þ ZE (1.0312) as representative of an automotive application. For both welding processes, the main influences on the resulting environmental impact categories are evaluated and compared. The requirements for ecological efficient welding processes are discussed and implemented.
KW - Resistance spot welding
KW - Carbon dioxide footprint
KW - Environmental impact categories
KW - Laser beam welding
KW - Life cycle assessment
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-566458
DO - https://doi.org/10.1002/adem.202101343
SN - 1438-1656
VL - 24
IS - 6
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56645
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Batahgy, A.
A1 - Elkousy, M.
A1 - Al-Rahman, A.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Gook, S.
T1 - Retaining Mechanical Properties of GMA-Welded Joints of 9%Ni Steel Using Experimentally Produced Matching Ferritic Filler Metal
N2 - Motivated by the loss of tensile strength in 9%Ni steel arc-welded joints performed using commercially available Ni-based austenitic filler metals, the viability of retaining tensile strength using an experimentally produced matching ferritic filler metal was confirmed. Compared to the austenitic Ni-based filler metal (685 MPa), higher tensile strength in gas metal arc (GMA) welded joints was achieved using a ferritic filler metal (749 MPa) due to its microstructure being similar to the base metal (645 MPa). The microstructure of hard martensite resulted in an impact energy of 71 J (-196 °C), which was two times higher than the specified minimum value of _>34 J. The
tensile and impact strength of the welded joint is affected not only by its microstructure, but also by the degree of its mechanical mismatch depending on the type of filler metal. Welds with a harder microstructure and less mechanical mismatch are important for achieving an adequate combination of tensile strength and notched impact strength. This is achievable with the cost-effective ferritic filler metal. A more desirable combination of mechanical properties is guaranteed by applying low preheating temperature (200 °C), which is a more practicable and economical solution compared to the high post-weld heat treatment (PWHT) temperature (580 °C) suggested by other research.
KW - 9%Ni steel
KW - Ni-based austenitic filler metal
KW - Mechanical mismatching
KW - Microstructure
KW - Post-weld heat treatment
KW - Preheating
KW - Matching ferritic filler metal
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564610
DO - https://doi.org/10.3390/ma15238538
SN - 1996-1944
VL - 15
IS - 23
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-56461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, S.
A1 - Midik, A.
A1 - Biegler, M.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Joining 30 mm Thick Shipbuilding Steel Plates EH36 Using a Process Combination of Hybrid Laser Arc Welding and Submerged Arc Welding
N2 - This article presents a cost-effective and reliable method for welding 30 mm thick sheets of shipbuilding steel EH36. The method proposes to perform butt welding in a two-run technique using hybrid laser arc welding (HLAW) and submerged arc welding (SAW). The HLAW is performed as a partial penetration weld with a penetration depth of approximately 25 mm. The SAWis carried out as a second run on the opposite side. With a SAWpenetration depth of 8 mm, the weld cross-section is closed with the reliable intersection of both passes. The advantages of the proposed welding method are: no need for forming of the HLAW root; the SAW pass can effectively eliminate pores in the HLAWroot; the high stability of the welding process regarding the preparation quality of the weld edges. Plasma cut edges can be welded without lack of fusion defects. The weld quality achieved is confirmed by destructive tests.
KW - Shipbuilding steel
KW - Hybrid laser arc welding
KW - Submerged arc welding
KW - Hardness
KW - Bending test
KW - Two-run welding technique
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556090
DO - https://doi.org/10.3390/jmmp6040084
SN - 2504-4494
VL - 6
IS - 4
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-55609
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Bähring, S.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Quality Prediction in Directed Energy Deposition Using Artificial Neural Networks Based on Process Signals
N2 - The Directed Energy Deposition process is used in a wide range of applications including the repair, coating or modification of existing structures and the additive manufacturing of individual parts. As the process is frequently applied in the aerospace industry, the requirements for quality assurance are extremely high. Therefore, more and more sensor systems are being implemented for process monitoring. To evaluate the generated data, suitable methods must be developed. A solution, in this context, was the application of artificial neural networks (ANNs). This article demonstrates how measurement data can be used as input data for ANNs. The measurement data were generated using a pyrometer, an emission spectrometer, a camera (Charge-Coupled Device) and a laser scanner. First, a concept for the extraction of relevant features from dynamic measurement data series was presented. The developed method was then applied to generate a data set for the quality prediction of various geometries, including weld beads, coatings and cubes. The results were compared to ANNs trained with process parameters such as laser power, scan speed and powder mass flow. It was shown that the use of measurement data provides additional value. Neural networks trained with measurement data achieve significantly higher prediction accuracy, especially for more complex geometries.
KW - DED
KW - Artificial neural network
KW - Data preparation
KW - Quality assurance
KW - Process monitoring
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555063
DO - https://doi.org/10.3390/app12083955
SN - 2076-3417
VL - 12
IS - 8
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-55506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding
N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. First, the local variation of the solidification sequence of the weld pool causes an increase in the hot-cracking susceptibility due to a locally delayed solidification. Second, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g., during the welding with filler materials, is blocked. This leads to a non-homogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results that were supported by selected experimental validation results.
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
KW - Porosity
KW - Numerical process simulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557759
DO - https://doi.org/10.2351/7.0000733
SN - 1042-346X
VL - 34
IS - 4
SP - 1
EP - 7
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-55775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brunner-Schwer, C.
A1 - Simón Muzás, Juan
A1 - Biegler, M.
A1 - Hilgenberg, Kai
A1 - Rethmeier, Michael
T1 - Laser Welding of L-PBF AM components out of Inconel 718
N2 - With regard to efficient production, it is desirable to combine the respective advantages of additively and conventionally manufactured components. Particularly in the case of large-volume components that also include filigree or complex structures, it makes sense to divide the overall part into individual elements, which afterwards have to be joined by welding.
The following research represents a first step in fundamentally investigating and characterizing the joint welding of Laser Powder Bed Fusion (L-PBF) components made of Inconel 718. For this purpose, bead-on-plate welds were performed on plates manufactured using the L-PBF process and compared with the conventionally manufactured material. Conventional laser beam welding was used as welding process. The weld geometry was investigated as a function of the L-PBF build-up orientation. It was found that the welding depth and weld geometry differ depending on this orientation and in comparison to the conventional material.
T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser Welding
KW - L-PBF
KW - PBF-LB/M
KW - Seam geometry
KW - Bead-on-plate welds
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560012
DO - https://doi.org/10.1016/j.procir.2022.08.072
SN - 2212-8271
VL - 111
SP - 92
EP - 96
PB - Elsevier B.V.
AN - OPUS4-56001
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Improvement of Charpy impact toughness by using an AC magnet backing system for laser hybrid welding of thick S690QL steels
N2 - The study deals with the influence of the heat input and the resulting cooling times on the microstructure and Charpy impact toughness of single-pass laser hybrid welded 20-mm thick high-strength steel S690QL. The main focus is on the change of the mechanical properties over the entire seam thickness. The cooling times were measured in-situ using a pyrometer and an optical fibre in three different depths of the seam where Charpy impact test specimens were also later taken. Thereby, three different heat inputs from 1.3 kJ/mm to 2 kJ/mm were investigated. Despite the observed decreased values of both t8/5-cooling time and the Charpy impact toughness in the root part of the seam, the required impact toughness of 38 J/cm2 could be reached in dependance on applied heat input, especially at the heat input of 1.6 kJ/mm.
T2 - 12th CIRP conference on photonic technologies [lane 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Thick-plate welding
KW - Laser hybrid welding
KW - Electromagnetic backing
KW - Charpy impact toughness
KW - Thermal cycles
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563731
DO - https://doi.org/10.1016/j.procir.2022.08.067
VL - 111
SP - 462
EP - 465
PB - Elsevier B.V.
AN - OPUS4-56373
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Srinivasan, Krishnanand
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser Metal Deposition of Rene 80—Microstructure and Solidification Behavior Modelling
N2 - New developments in nickel-based superalloys and production methods, such as the use of additive manufacturing (AM), can result in innovative designs for turbines. It is crucial to understand how the material behaves during the AM process to advance the industrial use of these techniques. An analytical model based on reaction–diffusion formalism is developed to better explain the solidification behavior of the material during laser metal deposition (LMD). The well-known Scheil–Gulliver theory has some drawbacks, such as the assumption of equilibrium at the solid–liquid interface, which is addressed by this method. The solidified fractions under the Scheil model and the pure equilibrium model are calculated using CALPHAD simulations. A differential scanning calorimeter is used to measure the heat flow during the solid–liquid phase transformation, the result of which is further converted to solidified fractions. The analytical model is compared with all the other models for validation.
KW - Laser metal deposition
KW - Solidification behavior
KW - Additive manufacturing
KW - Analytical model
KW - Nickel‐based superalloy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612095
DO - https://doi.org/10.3390/mi15101234
SN - 2072-666X
VL - 15
IS - 10
SP - 1
EP - 14
PB - MDPI
AN - OPUS4-61209
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Determination of critical local straining conditions for solidification cracking at laser beam welding by experimental and numerical methods
N2 - AbstractThe phenomenon of solidification cracking has been the subject of numerous research projects over the years. Great efforts have been made to understand the fundamentals of hot cracking. It is generally agreed that solidification cracks form in the solidification range between the liquidus and solidus temperatures under the combination of thermal, metallurgical and mechanical factors. There is still a need to determine the time‐resolved strain distribution in the crack‐sensitive region in order to analyse the local critical conditions for solidification cracking phenomena. This was a strong motivation for the development of a measurement system used in this study to estimate the local strains and strain rates in the zone where the solidification crack is expected to occur. The laser beam welding experiments were conducted using the Controlled‐Tensile‐Weldability test (CTW test) to apply an external strain condition during welding to generate solidification cracks. The CTW test is a test method for investigating the susceptibility of laser‐welded joints to solidification cracking, in which the sample can be subjected to a defined strain at a defined strain rate during welding.In combination with experimental investigations, numerical simulations provide spatially detailed and time‐dependent information about the strain development during the welding process, especially regarding the critical conditions for solidification cracking. Therefore, this tool was also used in the present study to evaluate the accuracy of measurement methods and to estimate experimentally derived values and their concrete influence on the formation of solidification cracks. By integrating experimental methods and numerical simulations, this study investigates the spatially resolved and temporally changing development of strain during welding, with a particular focus on the critical conditions that lead to the formation of solidification cracks. The use of numerical simulations serves a dual purpose by validating the accuracy of measurement methods and examining experimentally determined values for their actual influence on the formation of solidification cracks. A three‐dimensional finite element (FE) model implemented with ANSYS is used to simulate strains and stresses during welding. The credibility of the model was first established by validation using experimental temperature measurements. Subsequently, structural simulations were carried out under external load. The results of the simulations showed commendable agreement with the strain measurements performed using the developed technique.
KW - Laser beam welding
KW - Solidification cracking
KW - FEM simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612044
DO - https://doi.org/10.1002/pamm.202400020
SN - 1617-7061
VL - 24
IS - 2
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-61204
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gumenyuk, Andrey
A1 - Üstündağ, Ömer
A1 - Pelz, Till
A1 - Bakir, Nasim
A1 - Gerhards, Benjamin
A1 - Schleser, Markus
A1 - Rethmeier, Michael
T1 - Single pass laser vacuum welding of thick steel plates using electromagnetic support
N2 - The increasing demand for renewable energy produced by offshore wind turbines goes along with an increased demand in the production of offshore wind turbine foundations, so called “monopiles”, which are made by joining thick metal sheets. The industrial standard of multi-layer submerged arc welding (SAW) for joining of thick metal sheets is the current bottleneck in the production of monopiles. A possible increase in productivity by the implementation of high-power laser welding in a newly developed mobile vacuum chamber (MoVac) and an electromagnetic root support is the subject of this study. Single run butt welds are performed in flat position on S355 mild steel of thicknesses up to 80 mm using a disc laser system with 1030 nm wavelength and a maximum output of 60 kW. The laser optic is fixed on the MoVac-System which is held and manipulated by an articulated robot.
KW - Laser beam welding
KW - Laser welding with mobile vacuum
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612068
DO - https://doi.org/10.1016/j.procir.2024.08.145
VL - 124
SP - 418
EP - 423
PB - Elsevier BV
AN - OPUS4-61206
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Assessment of keyhole stability in laser beam welding with external magnetic field using numerical simulation
N2 - The challenge of understanding the physical mechanisms behind porosity reduction by a magnetic field during laser beam welding (LBW) is partly due to the difficulty in quantitatively evaluating keyhole stability. The commonly used index, such as keyhole depth, is typically one-dimensional, which is insufficient to capture the dynamic and three-dimensional fluctuations of the keyhole. In this paper, by utilizing a 3D multiphysical model of LBW with magnetic field, a novel keyhole geometry reconstruction algorithm has been developed to describe the keyhole profile and its fluctuation in a statistical manner to evaluate keyhole stability quantitatively. An equivalent diameter is proposed in this algorithm to reduce the irregularity of the keyhole geometry. The calculation results indicate that the time-averaged keyhole shape over 300 ms in the LBWof steel is conical, regardless of the application of an external magnetic field, which provides a more representative shape. Meanwhile, it is observed from the statistical aspect that the keyhole diameter becomes smaller, except the top part, under the influence of the magnetic field. The standard deviation of the equivalent diameter can be used as a physical variable to assess the keyhole stability quantitatively. The application of an external magnetic field can produce a noticeable reduction of the standard deviation of the equivalent diameter, namely, stabilizing the keyhole during LBW of steel. However, the different contribution from the keyhole stability affected by a magnetic field in suppressing porosity is different with materials.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 04.11.2024
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Keyhole shape
KW - Keyhole stability
KW - Magnetic field
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614984
DO - https://doi.org/10.2351/7.0001528
VL - 36
IS - 4
SP - 1
EP - 7
PB - AIP Publishing
CY - Melville, NY
AN - OPUS4-61498
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Assessment of keyhole stability in laser beam welding with external magnetic field using numerical simulation
N2 - The challenge of understanding the physical mechanisms behind porosity reduction by a magnetic field during laser beam welding (LBW) is partly due to the difficulty in quantitatively evaluating keyhole stability. The commonly used index, such as keyhole depth, is typically one-dimensional, which is insufficient to capture the dynamic and three-dimensional fluctuations of the keyhole. In this paper, by utilizing a 3D multiphysical model of LBW with magnetic field, a novel keyhole geometry reconstruction algorithm has been developed to describe the keyhole profile and its fluctuation in a statistical manner to evaluate keyhole stability quantitatively. An equivalent diameter is proposed in this algorithm to reduce the irregularity of the keyhole geometry. The calculation results indicate that the time-averaged keyhole shape over 300 ms in the LBW of steel is conical, regardless of the application of an external magnetic field, which provides a more representative shape. Meanwhile, it is observed from the statistical aspect that the keyhole diameter becomes smaller, except the top part, under the influence of the magnetic field. The standard deviation of the equivalent diameter can be used as a physical variable to assess the keyhole stability quantitatively. The application of an external magnetic field can produce a noticeable reduction of the standard deviation of the equivalent diameter, namely, stabilizing the keyhole during LBW of steel. However, the different contribution from the keyhole stability affected by a magnetic field in suppressing porosity is different with materials.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Hollywood, Los Angeles, USA
DA - 04.11.2024
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Keyhole shape
KW - Keyhole stability
KW - Magnetic field
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616024
DO - https://doi.org/10.2351/7.0001528
VL - 36
IS - 4
SP - 1
EP - 7
PB - AIP Publishing
AN - OPUS4-61602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gumenyuk, Andrey
A1 - Bakir, Nasim
A1 - Rethmeier, Michael
T1 - Two-colour thermography for measurement of temperature distribution in laser beam welding
N2 - Solidification cracking is a frequently observed phenomenon in laser beam welding of austenitic stainless steels and other metallic alloys. Characterisation of cracking susceptibility requires knowledge of the precise and spatially resolved temperature distribution near the solidification front in the welding process. Thermography is a standard tool that provides a qualitative estimate of the 2D temperature field. The general disadvantage of this method is its dependence on the emission characteristics of the measured object. For welding applications, these can vary significantly in the temperature range above and below the melting temperature. For this purpose, we have developed a thermography-based measurement technique using a SWIR camera system in combination with two narrow bandpass filters that use the principle of two-wavelength pyrometry to estimate absolute temperature values. This technique was used to determine the temperature distributions and gradients near the solidification front of laser-welded austenitic steel. The results were validated by other measurements.
KW - Laser beam welding
KW - Two-colour thermography
KW - Solidification cracking
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612070
DO - https://doi.org/10.1016/j.procir.2024.08.155
VL - 124
SP - 468
EP - 471
PB - Elsevier BV
AN - OPUS4-61207
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical studies of magnetohydrodynamic technology in suppressing process porosity during laser beam welding
N2 - The magnetohydrodynamic (MHD) technology is employed to mitigate the porosity problem during partial penetration laser beam welding (LBW) of 10 mm thick aluminum alloy. The effectiveness and universal applicability of the MHD technology in reducing porosity during the LBW process are confirmed by a reduction in the porosity ratio of more than 89%. A transient 3D multi-physical model coupled with the MHD effect has been developed to investigate the suppression mechanism of process porosity. Due to the influence of Lorentz force, there is an obvious change in the weld pool length. This change widens the escaping channel of bubbles escaping from the weld pool. The application of an oscillating magnetic field changes the fluid flow pattern noticeably, whose influence on the formation of porosity defects is highly complicated and nonlinear.
T2 - CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Aluminum alloy
KW - Process Porosity
KW - Porosity suppression
KW - Magnetohydrodynamic technology
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616053
DO - https://doi.org/10.1016/j.procir.2024.08.175
VL - 124
SP - 565
EP - 569
PB - Elsevier B.V.
AN - OPUS4-61605
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Plarre, Rüdiger
A1 - Zocca, Andrea
A1 - Spitzer, Andrea
A1 - Benemann, Sigrid
A1 - Gorbushina, Anna
A1 - Li, Y.
A1 - Waske, Anja
A1 - Funk, Alexander
A1 - Wilgig, Janka
A1 - Günster, Jens
T1 - Searching for biological feedstock material: 3D printing of wood particles from house borer and drywood termite frass
N2 - Frass (fine powdery refuse or fragile perforated wood produced by the activity of boring insects) of larvae of the European house borer (EHB) and of drywood termites was tested as a natural and novel feedstock for 3D-printing of wood-based materials. Small particles produced by the drywood termite Incisitermes marginipennis and the EHB Hylotrupes bajulus during feeding in construction timber, were used. Frass is a powdery material of particularly consistent quality that is essentially biologically processed wood mixed with debris of wood and faeces. The filigree-like particles flow easily permitting the build-up of woodbased structures in a layer wise fashion using the Binder Jetting printing process. The Quality of powders produced by different insect species was compared along with the processing steps and properties of the printed parts. Drywood termite frass with a Hausner Ratio HR = 1.1 with ρBulk = 0.67 g/cm3 and ρTap = 0.74 g/cm3 was perfectly suited to deposition of uniformly packed layers in 3D printing. We suggest that a variety of naturally available feedstocks could be used in environmentally responsible approaches to scientific material sciences/additive manufacturing.
KW - 3D printing
KW - X-ray tomographic
KW - SEM micrography
KW - Drywood termite
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521517
DO - https://doi.org/10.1371/journal.pone.0246511
VL - 16
IS - 2
SP - e0246511
AN - OPUS4-52151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tölle, Florian
A1 - Gumenyuk, Andrey
A1 - Gebhardt, Moritz Oliver
A1 - Rethmeier, Michael
T1 - Post-weld residual stress mitigation by scanning of a defocused laser beam
N2 - High welding residual stresses can cause service life reducing consequences. Even though many processes have been developed to reduce these stresses, they are only applicable for wider welds and simple component geometries or are cost-intensive, respectively. The presented method uses a defocused beam after welding for heating the material regions on both sides of the weld. In this way, the welding stresses are decreased without contacting the surfaces using the available equipment. Different process parameters could be used depending on the component geometry and the laser power. The mechanism and the influence of the process parameters were investigated by FEM-simulation and experiments on S355J2+N steel and showed a stress reduction of about 73%.
T2 - Lasers in Manufacturing 2011 - Proceedings of the Sixth International WLT Conference on Lasers in Manufacturing
CY - Munich, Germany
DA - 23.05.2011
KW - Residual stresses
KW - Stress reduction
KW - High energy beam welding
KW - Post-weld heat treatment
KW - Laser scanner optics
PY - 2011
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-238482
DO - https://doi.org/10.1016/j.phpro.2011.03.052
SN - 1875-3892
VL - 12
IS - 1
SP - 410
EP - 418
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-23848
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jahnke, Annika
A1 - Beck, Aaron J.
A1 - Becker, Richard L.
A1 - Bedulina, Daria
A1 - Braun, Ulrike
A1 - Gerdts, Gunnar
A1 - Hildebrandt, Lars
A1 - Joerss, Hanna
A1 - Klein, Ole
A1 - Korduan, Janine
A1 - Laforsch, Christian
A1 - Lannig, Gisela
A1 - Leslie, Heather A.
A1 - Lips, Stefan
A1 - Menger, Frank
A1 - Nabi, Deedar
A1 - Oberbeckmann, Sonja
A1 - Primpke, Sebastian
A1 - Pröfrock, Daniel
A1 - Ramsperger, Anja F.R.M.
A1 - Römerscheid, Mara
A1 - Schmitt-Jansen, Mechthild
A1 - Scholz-Böttcher, Barbara M.
A1 - Tröppner, Oliver
A1 - Wendt-Potthoff, Katrin
A1 - Kühnel, Dana
T1 - Perspective article: Multisectoral considerations to enable a circular economy for plastics
N2 - Plastics are widely used but improper disposal and release lead to increasing global pollution, threatening environmental and human health. To address this issue, we suggest intersectoral collaboration to achieve zero plastic pollution. The outcomes of the project P-LEACH demonstrated the enormous complexity and range of potential toxic effects of plastic-associated chemicals and micro-/nanoplastics released into water from UV-weathered plastics. We initiated an intersectoral dialogue amongst scientists, manufacturers, regulators and representatives of civil society about how to alleviate the negative impacts of plastic pollution. Circular economy offers a framework for selecting non-toxic chemicals, extending product (re)use, and waste reduction, which act to alleviate pollution when applied to plastics. We suggest three measures to advance a circular economy of plastics: 1.) Increase simplicity of chemicals in virgin plastics combined with transparent information on the contents; 2.) Consider recyclability already in plastic material and product design; 3.) Foster communication through intersectoral dialogue. Major cornerstones are the provision of standardized, easy-to-use tools to characterize plastics and plastic leachates chemically and (eco)toxicologically, the enhancement of citizen awareness enabling them to make informed choices, the creation of economic incentives for manufacturers, and sector-specific regulations to provide products that safeguard environmental and human health.
KW - Plastics
KW - Circular economy
KW - Cross-sectoral dialogue
KW - Recyclability
KW - Plastic-associated chemicals
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-638280
DO - https://doi.org/10.1016/j.jhazmat.2025.139326
SN - 0304-3894
VL - 496
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-63828
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battistella, Beatrice
A1 - Revill, Adam
A1 - Venzago, Cornel
A1 - Hoffmann, Volker
A1 - Agudo Jácome, Leonardo
A1 - Al-Sabbagh, Dominik
A1 - Recknagel, Sebastian
A1 - Abad, Carlos
T1 - Depth-Resolved Lithium Isotope Fractionation as a Diagnostic of Interphase Evolution and Degradation in Lithium-Ion Batteries
N2 - Lithium isotopic fractionation is well-established in dynamic geochemical systems; however, its role in lithium-ion batteries (LIBs) remains uninvestigated. Herein, we report the first depth-resolved demonstration that isotopic separation occurs during Li-ion cell operation whose magnitude depends on the cycling history. Using depth-resolved glow discharge mass spectrometry, we monitored the 7Li/6Li ratio in LiNi0.333Mn0.333Co0.333O2 (NMC111)||graphite coin cell electrodes at defined life-cycle stages. Different charging rates were examined to get mechanistic insight into kinetic and thermodynamic control in the fractionation process. Although pristine electrodes exhibit a uniform isotopic ratio, cycled electrodes show a distinct 7Li enrichment in the positive electrode and a corresponding accumulation of 6Li at the surface of the negative electrode. The degree of isotopic separation varies with the charging rate. Isotopic signatures correlate with capacity fading, indicating lithium isotope mapping as a sensitive diagnostic tool for tracking electrode degradation and the evolution of the electrode–electrolyte interphases in LIBs.
KW - Lithium-Ion Battery
KW - Li Isotopes
KW - Glow Discharge Mass Spectrometry GD-MS
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657229
DO - https://doi.org/10.1021/acsenergylett.5c0413737
SN - 2380-8195
VL - 11
IS - 3
SP - 2851
EP - 2857
PB - ACS Publications
AN - OPUS4-65722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strommer, Bettina
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
A1 - Böhning, Martin
T1 - Networking Skills: The Effect of Graphene on the Crosslinking of Natural Rubber Nanocomposites with Sulfur and Peroxide Systems
N2 - Tailored crosslinking in elastomers is crucial for their technical applications. The incorporation of nanoparticles with high surface-to-volume ratios not only leads to the formation of physical networks and influences the ultimate performance of nanocomposites, but it also affects the chemical crosslinking reactions. The influence of few-layer graphene (FLG) on the crosslinking behavior of natural rubber is investigated. Four different curing systems, two sulfur-based with different accelerator-to-sulfur ratios, and two peroxide-based with different peroxide concentrations, are combined with different FLG contents. Using differential scanning calorimetry (DSC), vulcametry (MDR) and swelling measurements, the results show an accelerating effect of FLG on the kinetics of the sulfur-based curing systems, with an exothermic reaction peak in DSC shifted to lower temperatures and lower scorch and curing times in the MDR. While a higher accelerator-to-sulfur ratio in combination with FLG leads to reduced crosslinking densities, the peroxide crosslinkers are hardly affected by the presence of FLG. The good agreement of crosslink densities obtained from the swelling behavior confirms the suitability of vulcameter measurements for monitoring the complex vulcanization process of such nanocomposite systems in a simple and efficient way. The reinforcing effect of FLG shows the highest relative improvements in weakly crosslinked nanocomposites.
KW - Nanocomposite
KW - Elastomers
KW - Graphene
KW - Crosslinking
KW - Network
KW - Rubber
KW - Vulcanization
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560409
DO - https://doi.org/10.3390/polym14204363
VL - 14
IS - 20
PB - MDPI
AN - OPUS4-56040
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Balderas-Xicohtencatl, R.
A1 - Villajos, José Antonio
A1 - Casabán, J.
A1 - Wong, D.
A1 - Maiwald, Michael
A1 - Hirscher, M.
T1 - ZIF‑8 Pellets as a Robust Material for Hydrogen Cryo-Adsorption Tanks
N2 - Cryoadsorption on the inner surface of porous materials is a promising solution for safe, fast, and reversible hydrogen storage. Within the class of highly porous metal−organic frameworks, zeolitic imidazolate frameworks (ZIFs) show high thermal, chemical, and mechanical stability. In this study, we selected ZIF-8 synthesized mechanochemically by twin-screw extrusion as powder and pellets. The hydrogen storage capacity at 77 K and up to 100 bar has been analyzed in two laboratories applying three different measurement setups showing a high reproducibility. Pelletizing ZIF-8 increases the packing density close to the corresponding value for a single crystal without loss of porosity, resulting in an improved volumetric hydrogen storage capacity close to the upper limit for a single crystal. The high volumetric uptake combined with a low and constant heat of adsorption provides ca. 31 g of usable hydrogen per liter of pellet assuming a temperature−pressure swing adsorption process between 77 K − 100 bar and 117 K − 5 bar. Cycling experiments do not indicate any degradation in storage capacity. The excellent stability during preparation, handling, and operation of ZIF-8 pellets demonstrates its potential as a robust adsorbent material for technical application in pilot- and full-scale adsorption vessel prototypes.
KW - Hydrogen adsorption storage
KW - Metal−organic frameworks
KW - ZIF-8
KW - Cryoadsorption
KW - Hydrogen Storage
KW - MefHySto
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569473
DO - https://doi.org/10.1021/acsaem.2c03719
SN - 2574-0962
SP - 1
EP - 8
PB - ACS Publications
CY - Washington DC
AN - OPUS4-56947
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schubnell, J.
A1 - Konidena, S. K.
A1 - Jung, M.
A1 - Braun, M.
A1 - Ehlers, S.
A1 - Madia, Mauro
A1 - Kannengießer, Thomas
A1 - Löschner, D.
T1 - Approach for the probabilistic fatigue assessment of welded joints based on the local geometry of the weld seam
N2 - Welded joints show large variation of the weld toe geometry along the weld seam, which is one important reason for the comparably large scatter in fatigue life. Therefore, it is crucial to take the local geometry at the weld toe into account, to reduce the conservatism in fatigue assessment of welded joints. This study is based on the IBESS procedure for the calculation of the fatigue strength, whereby the evaluation of local geometrical parameters is carried out by means of 3D surface scans. The approach is validated against 26 fatigue test series. The fatigue life is in general overpredicted, whereas good agreement is achieved for high stress ratio (R = 0.5). A sensitivity analysis conducted with IBESS shows that weld toe radii ρ < 2 mm and flank angle α < 30° have a significant influence on the calculated fatigue strength. In contrast to this, no strong correlation between ρ and the fatigue strength was determined experimentally in this study.
KW - 3D Scanning
KW - Fatigue Strength
KW - Fracture Mechanics
KW - IBESS Approach
KW - Local Weld Geometry
KW - Welded Joints
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585700
DO - https://doi.org/10.1111/ffe.14170
SN - 8756-758X
SP - 1
EP - 20
PB - Wiley
AN - OPUS4-58570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sanchez Olivares, G.
A1 - Battig, Alexander
A1 - Goller, Sebastian M.
A1 - Rockel, Daniel
A1 - Ramirez Gonzáles, V.
A1 - Schartel, Bernhard
T1 - Imparting Fire Retardancy and Smoke Suppression to Leather during Tanning Processes
N2 - Leather is considered a luxury good when used in seating and upholstery. To improve safety, flame retardancy in leather is usually achieved through various finishing processes such as spray or roller coating. These treatments require processing steps that cost time and are laborintensive. One avenue to achieving flame retardancy in leather is to add flame retardants during the tanning process. However, the influence on flame retardancy exerted by specific intumescent additives specifically added during leather tanning has yet to be investigated. This work explores the roles played by intumescent additive compounds in flame retarding leather when they are added during tanning instead of applied as a coating. Via a systematic investigation of various compound mixtures, the flame retardant effects in the condensed and the gas phases are elucidated. The results show a strong impact of melamine in the gas phase and of polyphosphates in the condensed phase. Their impact was quantified in fire and smoke analysis, showing a 14% reduction in the peak of heat release rate, strongly reduced burning lengths, and a 20% reduction in total smoke release compared to nontreated leather. These results illuminate the key role played by specific compounds in the flame retardancy of leather, particularly when they are added specifically during the tanning process instead of being applied as a coating.
This method has great potential to reduce processing steps, lower costs, and improve material safety.
KW - Leather
KW - Fire protection
KW - Intumescent additives
KW - Smoke suppression
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564777
DO - https://doi.org/10.1021/acsomega.2c05633
SN - 2470-1343
VL - 7
IS - 48
SP - 44156
EP - 44169
PB - ACS
AN - OPUS4-56477
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strommer, Bettina
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
A1 - Böhning, Martin
T1 - The quantification of anisotropy in graphene/natural rubber nanocomposites: Evaluation of the aspect ratio, concentration, and crosslinking
N2 - In the processing of nanocomposites, high shear stresses at elevated tempera-tures orient two-dimensional nanoparticles like graphene. This orientationleads to anisotropic mechanical, thermal or barrier properties of the nanocom-posite. This anisotropy is addressed in this study by comparing graphene (few-layer graphene, FLG) with a nanoscaled carbon black (nCB) at a filler contentof 3 phr, by varying the vulcanization, and by comparing different FLG con-tents. Transmission electron microscopy gives insight into the qualitative ori-entation in the nanocomposite with FLG or nCB. The storage moduli paralleland normal to the orientation reveal the direction dependency of reinforce-ment through dynamic mechanical analysis (DMA). Dimensional swellingmeasurements show a restriction of the expansion parallel to the FLG orienta-tion, and an increased expansion normal to the orientation. The vulcanizationsystem and crosslinking determine the respective level of property values, andhigher crosslinking densities increase the anisotropy in DMA resulting invalues of up to 2.9 for the quantified anisotropy factor. With increasing FLGcontent, the anisotropy increases. A comparison of the results reveals swellingmeasurements as the most suitable method for the determination of anisot-ropy. Compared to recent literature, the presented processing induces higheranisotropy, leading to higher reinforcing effects in the direction of orientation
KW - Natural rubber
KW - Graphene
KW - Nanocomposite
KW - Mechanical properties
KW - Swelling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-571522
DO - https://doi.org/10.1002/app.53753
SN - 1097-4628
VL - 140
IS - 16
SP - 1
EP - 15
PB - Wiley online library
CY - Hoboken, New Jersey (USA)
AN - OPUS4-57152
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Han, Ying
A1 - Kruse, Julius
A1 - Rosalie, Julian
A1 - Radners, J.
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Influence of mean stress and overaging on fatigue life of aluminum alloy EN AW-2618A
N2 - Fatigue tests were performed on the forged aluminum alloy EN AW-2618A in the T61 state. Different stress ratios (R = -1, R = 0.1) were selected to study the influence of mean stress on fatigue life. Two overaged states (10 h/230 ◦C, 1000 h/230 ◦C) were also tested to investigate the influence of overaging on fatigue life. Transmission electron microscopy (TEM) was used to characterize the precipitates (S-phase), which are mainly responsible for the strength of the alloy. A fractographic analysis was also performed to determine the failure mode. Overaging reduces the fatigue life compared to the T61 state. The longer the aging time, the lower the fatigue resistance. The reason is the decrease in (yield) strength, which correlates with the radius of the S-phase: the precipitate radius increases by a factor of approximately two for the overaged states compared to the initial state. The analysis of the fracture surfaces showed crack initiation occurs predominantly on the outer surface and is
associated with the primary phases.
KW - Aluminum alloys
KW - Aging
KW - Fatigue
KW - Microstructure
KW - Electron microscopy
KW - S-Phase
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583708
DO - https://doi.org/10.1016/j.msea.2023.145660
SN - 0921-5093
VL - 886
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-58370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Turski Silva Diniz, Analice
A1 - Marti, J. M.
A1 - Schartel, Bernhard
T1 - High Heat Resistance Can Be Deceiving: Dripping Behavior of Polyamide 4.6 in Fire
N2 - Polyamide 4.6 (PA46) is a high-heat-resistant polymer, but it has no dripping resistance under fire. Three commercial grades of PA46 are investigated under UL 94 vertical fire test conditions. Their performances are discussed based on the materials’ structural, thermal, and rheological properties. PA46 presents flaming drops, whereas dripping is prevented in the flame-retarded PA46.
Friction-modified PA46 has increased flaming dripping. Temperature profiles of the specimens under fire and the temperature of the drops are measured by thermocouples. A UL 94 vertical test configuration consisting of two flame applications is designed to assess the quantitative dripping behavior of the set of materials by the particle finite element method (PFEM). Polymer properties (activation energy and Arrhenius coefficient of decomposition, char yield, density, effective heat of combustion, heat of decomposition, specific heat capacity, and thermal conductivity) in addition to rheological responses in high temperatures are estimated and measured as input parameters for the simulations. The dripping behavior obtained by simulated materials corresponds with the experimental results in terms of time and drop size. A consistent picture of the interplay of the different phenomena controlling dripping under fire appears to deliver a better understanding of the role of different materials’ properties
KW - Dripping
KW - UL 94
KW - PFEM
KW - High heat resistance
KW - Polyamide 4.6
KW - Flammability
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586015
DO - https://doi.org/10.1002/mame.202300091
SN - 1439-2054
SN - 1438-7492
VL - 308
IS - 10
SP - 1
EP - 11
PB - Wiley-VCH
AN - OPUS4-58601
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Ávila Calderón, Luis
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
A1 - Bruno, Giovanni
T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion
N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed.
KW - Creep
KW - Computed Tomography
KW - PBF-LB/M/316L
KW - Laser Powder Bed Fusion
KW - Microstructure
KW - AISI 316L
KW - Additive Manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574127
DO - https://doi.org/10.1002/adem.202201581
SP - 1
EP - 9
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-57412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Jürgens, Maria
A1 - Uhlemann, Patrick
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Experimental data from service-like creep-fatigue experiments on grade P92 steel
N2 - This article refers to the research article entitled “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times” [1]. It presents experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress. Such service-like (SL) tests with additional long-term stress- and strain-controlled dwell times are non-standard, rare, and expensive, making these data very valuable. They may be used to approximate cyclic softening in the technically relevant range, for the design of complex SL experiments, or for detailed analyses of stress-strain hystereses (e.g., for stress or strain partitioning methods, for the determination of hysteresis energies (work), inelastic strain components, etc.). In addition, the latter analyses may supply important input for advanced parametric lifetime modeling of components under creep-fatigue loading or model calibration parameters.
KW - Tempered martensite-ferritic steel
KW - Creep
KW - Stress relaxation
KW - Creep-fatigue
KW - Dwell times
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578407
DO - https://doi.org/10.1016/j.dib.2023.109333
SN - 2352-3409
VL - 49
SP - 1
EP - 9
PB - Elsevier Inc.
AN - OPUS4-57840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rockenhäuser, Christian
A1 - von Hartrott, P.
A1 - Skrotzki, Birgit
T1 - Brinell-Hardness data (HBW 2.5/62.5) of aluminum alloy EN AW-2618A after different aging times and temperatures
N2 - The article covers data on the Brinell hardness of the forged precipitation-hardened aluminum alloy EN AW-2618A in the initial T61 condition (i. e. slightly underaged) and after isothermal aging for up to 25,0 0 0 h at aging temperatures between 160 °C and 350 °C. In addition, the hardness was determined on specimens after creep testing at 190 °C and various stresses. The hardness decreases with increasing ag- ing time due to the microstructural evolution of the harden- ing precipitates. The drop occurs faster the higher the aging temperature. Aging under creep load additionally accelerates the hardness decrease.
KW - Aluminum alloy
KW - EN AW-2618A
KW - Brinell hardness
KW - Aging
KW - Creep
KW - Ostwald ripening
KW - Reheating
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567611
DO - https://doi.org/10.1016/j.dib.2022.108830
SN - 2352-3409
VL - 46
PB - Elsevier Inc.
AN - OPUS4-56761
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sunder, S.
A1 - Jauregui Rozo, Maria
A1 - Deshpande, H.
A1 - Neyer, A.
A1 - Papaiya, V.
A1 - Meinel, Dietmar
A1 - Schartel, Bernhard
A1 - Ruckdäschel, H.
T1 - Char to the Rescue: Processing and Transfer of Flame-Retardant Epoxy Resins, Adjusting the Fire Behavior and Post-Fire Structural Integrity of Glass Fiber Composites
N2 - Epoxy (EP) glass fiber reinforced composites (GFRCs) are extensively used in structural applications due to their excellent thermal and mechanical properties, but their inherent flammability limits fire-safe deployment. While numerous studies examine the flame retardancy of resins or individual composite systems, comprehensive studies evaluating simultaneous improvements in flame retardancy and post-fire mechanical integrity, specifically through prepreg processing, remain challenging. This study investigates the effectiveness and transferability of phosphorus-based flame retardant (FR) systems to diglycidyl ether of bisphenol A (DGEBA) and EP novolac resin matrices and their corresponding bidirectional glass fiber composites via prepregs. The FRs are chosen based on varying modes of action: ammonium polyphosphate with inorganic silicate (APP/InSi) primarily acts in the condensed phase (CP), and aluminum diethyl phosphinate with zinc hydroxystannate (AldietPO2/ZHS) is known to demonstrate both gas-phase (GP) and CP activity. Fire residues are tailored to compensate for structural defects from fire exposure. EP novolac, with higher aromaticity and cross-linking, possesses better inherent flame resistance compared to DGEBA. The novolac composites containing AldietPO2/ZHS simultaneously showed the highest retention of flexural properties after fire exposure and the best fire safety index. The experimental values of the post-fire flexural properties in the composites calibrated damage parameters in two theoretical models.
KW - Composites
KW - DGEBA
KW - Epoxy novolac
KW - Post-fire
KW - Prepregs
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643752
DO - https://doi.org/10.1002/pol.20250692
SN - 2642-4169
SN - 2642-4150
VL - 63
IS - 20
SP - 4295
EP - 4309
PB - Wiley
AN - OPUS4-64375
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rockel, Daniel
A1 - Sanchez Olivares, G.
A1 - Calderas, F.
A1 - Schartel, Bernhard
T1 - Two heads are better than one: Aluminum trihydroxide / phosphorous flame retardant combination in natural waste fiber biocomposites
N2 - Future polymeric materials that replace fossil fuel-based engineering plastics demand the use of renewable sources as well as the implementation of key properties such as flame retardancy, processing, and mechanical properties. This study focuses on the combination of aluminum trihydroxide (ATH) and phosphorus-based flame retardants in compositable thermoplastic starch reinforced with sustainable multifunctional leather waste fibers. The flame retardants engender different flame-retardant modes of action, improving overall performance when combined. The partial substitution of ATH with phosphorous flame retardant allowed a reduction in flame retardant loading. Materials with 90 phr of ATH reached a limiting oxygen index of 31.5 vol.-% and a UL-94 rating of V-1, whereas the combination of 73 phr ATH and 7 phr of diphenyl ocytyl phosphate achieved a V-0 rating and a slightly reduced peak of heat release rate. This study demonstrates the potential of multicomponent systems implementing waste fiber–reinforced biocomposites.
KW - Biocomposites
KW - Flame retardancy
KW - Phosphorous flame retardants
KW - Synergism
KW - Sustainability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639084
DO - https://doi.org/10.1016/j.polymertesting.2025.108938
SN - 0142-9418
SN - 1873-2348
VL - 150
SP - 1
EP - 17
PB - Elsevier Ltd.
AN - OPUS4-63908
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jauregui Rozo, Maria
A1 - Sunder, S.
A1 - Inasu, S.
A1 - Meinel, Dietmar
A1 - Ruckdäschel, H.
A1 - Schartel, Bernhard
T1 - Weaving Through Fire and Force: Fire Behavior and Fire Stability of Unidirectional, Bidirectional, and Woven Roving Glass-Fiber Composites
N2 - This study systematically investigates the transfer of flame retardants (FRs) from epoxy resins to composites. The flame-retardant composites are formulated using bisphenol A diglycidyl ether as the resin and dicyandiamide as the hardener, reinforced with glass fibers (GFs) using various textile architectures: unidirectional (UD), bidirectional (BD), and woven rovings (WR). These composites are evaluated using bench-scale fire stability tests and cone calorimeter experiments to assess critical parameters, including the temperature at failure, time to failure, and fire behavior. Among the tested configurations, UD-GFs demonstrate superior flame retardancy, fire stability, flammability, and mechanical performance, attributed to their higher residue yield, forming a more efficient protective char layer. However, the addition of FRs is limited by their impact on the material's mechanical properties. When the FR content increases to 30 and 50 wt.% of the resin, the composites exhibit a decrease in mechanical performance, adversely affecting both time to failure and temperature at failure. While adding FRs reduces the risk of fire propagation, it does not substantially enhance fire stability or mechanical performance.
KW - Fire Resistance
KW - Fiber-Reinforced Polymer Composites
KW - Fire Stability
KW - Glass Fibers
KW - Fire Behavior
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631220
SN - 1438-7492
SN - 1439-2054
VL - 310
IS - 5
SP - 2400432
PB - Wiley VHC-Verlag
AN - OPUS4-63122
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wagner, Jan
A1 - Dudziak, Mateusz
A1 - Falkenhagen, Jana
A1 - Rockel, Daniel
A1 - Reimann, H.-A
A1 - Schartel, Bernhard
T1 - This is the way: An evidence based route to phytic-acid–based flame retardant poly(lactide acid)
N2 - A systematic sequence of materials was investigated to develop phytic-acid (Phyt)–based flame retarded poly (lactide acid) (PLA), while factoring in molecular weight (MW), crystallinity and mechanical properties. Synergistic approaches were developed based on combinations with lignin and expandable graphite (EG), as well as by applying different Phyt salts of melamine (Mel), piperazine (Pip), and arginine (Arg). Compounds were twin screw extruded, injection molded, hot pressed and investigated with thermal analysis, size exclusion chromatography, infrared spectroscopy, tensile testing, limited oxygen index (LOI), UL 94, cone calorimeter, and scanning electron microscope. 16.7 wt.% flame retardant (FR) slightly enhances crystallization while MW remains unchanged in PLA Phyt Arg and PLA Phyt Mel. LOI was improved to 43.7 vol.% for PLA Phyt Arg, UL 94 V0 achieved for PLA Phyt Pip. Cone calorimeter results show total heat evolved reduced by 14 %, maximum average rate of heat emission 43 % lower, and peak heat release rate reduced by 50 % for PLA Phyt Mel. Phyt Mel combined with EG increased the char yield of PLA to 20 wt.% and 15.5 wt.% at 600 and 900 ◦C, respectively. Phyt is exploited to enhance char yield, stabilize the intumescent char, and lower the apparent effective heat of combustion. The combination of Phyt Mel and EG was proposed as an efficient FR for PLA via an evidence based developing route.
KW - Polylactide acid
KW - Intumescent flame retardant
KW - Phosphorous flame retardant
KW - Phytic acid
KW - Expandable graphite
KW - Melamine
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626395
DO - https://doi.org/10.1016/j.polymdegradstab.2025.111242
SN - 1873-2321
SN - 0141-3910
VL - 234
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-62639
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dey, R.
A1 - Dudziak, Mateusz
A1 - Prescher, A.
A1 - Kreitsmann, T.
A1 - Zhang, K.
A1 - Posten, C.
A1 - Thomson, C.
A1 - Schartel, Bernhard
A1 - Ullrich, M. S.
A1 - Thomson, L.
T1 - Sustainable Flame-Retardant Poly Lactic AcidBiocomposites Reinforced with Polyphosphate-EnrichedMicroalgae: Unlocking the Potential of Hyper-Compensation
N2 - This study examines the dual benefits of microalgae cultivation for wastewatertreatment and the enhancement of polylactic acid-based biocomposites. UsingDesmodesmus sp. in a photobioreactor, both batch and continuous operationsachieve total nitrogen (TN) and total phosphorus (TP) removal rates of up to99.9%, maintaining TN and TP levels below 0.02 mg L−1 in the effluent, aligningwith European discharge standards. Continuous cultivation increases biomassproductivity from 0.102 to 0.43 g L−1 day−1 , a 322% improvement over batchoperations. Nutrient starvation followed by reintroduction to nutrient-richwastewater induces hyper-compensation luxury uptake, with P-enrichedcells accumulating 1.33% intracellular P within six hours — 21% higherthan natural accumulation. The results reveal that luxury phosphorus uptakein microalgae follows a triphasic system of uptake and storage, challengingthe previously suggested biphasic model. When incorporated into Poly lacticacid (PLA), the biomass enhances versatility, offering potential replacementof inorganic P in industrial applications, particularly flame retardants.Pyrolysis and cone calorimetry confirm the thermal and fire-retardantbenefits, with a 20% reduction in peak heat release rate and increased charyield. This work highlights microalgae’s role in sustainable biocomposites,supporting wastewater treatment, nutrient recovery, and CO2 sequestration.
KW - biocomposites
KW - biopolymers
KW - Flame-retardant
KW - Hyper compensation
KW - Phycoremediation
KW - Wastewater treatment
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640408
DO - https://doi.org/10.1002/adsu.202500251
SN - 2366-7486
VL - 9
IS - 8
SP - 1
EP - 11
PB - Wiley VHC-Verlag
AN - OPUS4-64040
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröder, Jakob
A1 - Han, Ying
A1 - Fritsch, Tobias
A1 - Hejazi, Bardia
A1 - Ulbricht, Alexander
A1 - Skrotzki, Birgit
A1 - Bruno, Giovanni
T1 - X-ray computed tomography quantifies primary phases and reveals crack morphology in high-cycle fatigue of aluminum alloy EN AW-2618A
N2 - Since the introduction of high-strength aluminum alloys understanding their fatigue behavior is of high interest for the structural integrity of engineering components, in this context, the alloy EN AW-2618A gains its high strength from both nanometer size precipitates and micrometer size primary phases. The latter phases are often identified as crack initiation sites. In this study, it uses a combination of synchrotron and laboratory-based X-ray computed tomography to image and quantify such primary phases and the fatigue cracks appearing in interrupted tests. Based on the gray-level differences in the synchrotron X-ray computed tomography scans, this study is able to distinguish low- and high-absorbing particles. The dominant (volume fraction >99%) high absorbing primary phase can be quantified in good agreement with results of Thermo-Calc calculations. To image the fatigue crack, laboratory X-ray computed tomography scans are performed at different tensile loads to open the crack. The results show that with an appropriate crack opening tensile load, the fatigue crack morphology can be reliably revealed. Based on these results, the influence of the primary phases on the fatigue crack initiation and propagation are discussed.
KW - X-ray computed tomography
KW - Fatigue
KW - Aluminum
KW - Primary phases
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632724
DO - https://doi.org/10.1002/adem.202500235
SN - 1527-2648
SP - 1
EP - 9
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-63272
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Han, Ying
A1 - Schriever, Sina
A1 - von Hartrott, Philipp
A1 - Rockenhäuser, Christian
A1 - Skrotzki, Birgit
T1 - Creep dataset for aluminum alloy EN AW-2618A in the T61 and overaged condition 1000 h/190 °C
N2 - The article presents creep data for the precipitation-hardened aluminum alloy EN AW-2618A, which was tested in its initial slightly underaged T61 condition and after being aged at 190 °C for 1000 h. The creep test temperatures ranged between 160 °C and 230 °C, and the applied initial stresses between 40 MPa and 290 MPa. The testing times reached up to 4700 h. 19 data sets are provided as creep strain vs. time series. A data schema originally developed to manage creep reference data of a single-crystalline nickel-based superalloy was adapted for the research data set of the polycrystalline aluminum alloy and used to enrich the test data with extensive metadata. The dataset can be used to calibrate and validate creep models. The creep data supplement the hardness and microstructure data that have been previously published.
KW - Aluminum alloy EN AW-2618A
KW - Aging
KW - Overaging
KW - High temperature
KW - Creep
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641517
DO - https://doi.org/10.1016/j.dib.2025.112054
SN - 2352-3409
VL - 62
SP - 1
EP - 10
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-64151
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Willms, Thomas
A1 - Kryk, Holger
A1 - Hampel, Uwe
T1 - Towards a deeper understanding of the oxidation of isobutane to tert-butyl hydroperoxide in the liquid phase by an extended kinetic model - Initiation by di-tert-butyl peroxide
N2 - To date, the liquid phase oxidation of isobutane has not been comprehensively described in the literature, since
the established kinetic models include either the effect of the initiator or the autocatalytic nature of the oxidation
of isobutane, but not both. To overcome this deficiency, an extended kinetic model was developed and validated
using experimental data from the literature. It enabled for the first time the distinction of three different processes:
the oxidation of isobutane, the heterogeneous, unimolecular decomposition of tert-butyl hydroperoxide
on the reactor wall and the homogeneous decomposition reactions of TBHP in solution. The rate constant of the
heterogeneous unimolecular decomposition of TBHP on the wall surface of an untreated stainless-steel reactor,
was found to be two to five times higher than that which was observed in a passivated steel reactor. However,
similar values for the respective parameters describing the first-order decomposition of TBHP and the oxidation
of isobutane were obtained in both reactors. In the non-passivated stainless-steel reactor, the second order
decomposition of TBHP was absent. The results were compared with published data.
KW - Isobutane oxidation
KW - TBHP
KW - DTBP
KW - Initiator
KW - Autocatalysis
KW - Wall effect
KW - Liquid phase
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659218
DO - https://doi.org/10.1016/j.ces.2026.123523
SN - 1873-4405
VL - 329
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65921
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
A1 - Jokisch, Torsten
A1 - Olbricht, Jürgen
A1 - Fedelich, Bernard
T1 - Fatigue crack growth in nickel-based alloy 247DS with side-brazed pre-sintered preform
N2 - Pre-sintered preform (PSP) brazing is employed in the repair of gas turbine components made of nickel-based alloys, including restoring the surface and dimensions of turbine blades and vanes. This study investigates the fatigue crack growth (FCG) behavior of Alloy 247DS specimens with side-brazed PSP material, mimicking a typical sandwich structure formed during such repairs. FCG tests were conducted at an elevated temperature of 950 °C and a stress ratio (R) of 0.1 on specimens with PSP layer thicknesses of 1.5 mm, 2 mm, 3 mm, and 4.5 mm to assess the influence of PSP thickness on fatigue crack growth behavior. Fractographic and metallographic analyses were performed to elucidate the underlying crack growth mechanisms and the microstructural characteristics of both materials. The results revealed that a crack consistently initiated in the PSP material, originating from the starter notch, particularly at the specimen corner during the pre-cracking phase. Additionally, crack propagation in the PSP material consistently advanced ahead of the crack in the Alloy 247DS. This crack growth behavior is attributed to the difference in elastic properties and microstructural differences between the PSP and base material. Metallographic analysis revealed the presence of porosity and brittle precipitates within the PSP material, which led to faster intergranular crack growth. Conversely, Alloy 247DS exhibited transgranular crack growth, contributing to the observed crack propagation behavior. This study demonstrates the applicability of standard FCG testing methods and an approach to characterize the FCG behavior in sandwich specimens, where crack growth occurs simultaneously in both materials, providing a preliminary understanding of crack growth behavior in Alloy 247DS with side-brazed PSP.
KW - High-temperature fatigue crack growth (FCG)
KW - Nickel-based alloys
KW - Alloy 247DS
KW - Pre-Sintered Preform (PSP)
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629783
DO - https://doi.org/10.1016/j.ijfatigue.2025.108961
VL - 197
SP - 1
EP - 13
PB - Elsevier BV
AN - OPUS4-62978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Buljak, Vladimir
A1 - Fritsch, Tobias
A1 - Bruno, Giovanni
T1 - Application of inverse analysis for characterization of local material properties in additively manufactured lattice structures
N2 - An inverse analysis (IA) procedure was coupled with X-ray Computed Tomography (XCT) data of lattice structures to identify the materials parameters of the lattice and successively predict the macroscopic behaviour of larger structures. The materials parameters were identified by minimizing the deviation between experimental and FEM simulated force–displacement data of a lattice unit cell; the same parameters were input to the simulation of the force–displacement behaviour of larger cells. The agreement between such simulations and the experimental data proved to be excellent. Since both the small- and large-scale cells were tested along the build direction, a simple isotropic material model was considered adequate to rationalize the experimental results. The approach proved that the IA and the FEM simulations are extremely powerful for material parameter identification and for the prediction of the mechanical behaviour of larger structures. We found that the materials parameters of PBF-L IN625 lattices substantially differ from the bulk properties. The latter cannot be used for FEM calculations.
KW - X-ray computer tomography
KW - Finite element modelling
KW - Large deformation
KW - IN625 nickel alloy
KW - Compression tests
KW - Digital volume correlation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659387
DO - https://doi.org/10.1007/s40964-026-01654-3
SN - 2363-9512
SP - 1
EP - 8
PB - Springer International Publishing
CY - Cham
AN - OPUS4-65938
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kaiser, Sebastian
A1 - Erxleben, Kjell
A1 - Silvayeh, Zahra
A1 - Gomboc, David
A1 - Rhode, Michael
A1 - Domitner, Josef
A1 - Kannengiesser, Thomas
T1 - Concept for measuring and calculating the temperature field during in-service welding of gas pipelines
N2 - In-service welding of pipelines without interrupting the internal gas flow is nowadays state of the art for the maintenance and extension of the grid. However, due to access restrictions, it is quite challenging or even impossible to measure local temperatures during welding and subsequent cooling. To address this issue, in the present work welding experiments were performed that consider representative weld configurations and process parameters relevant for in-service welding of gas pipelines. A flat steel sheet was multi-pass welded onto the outer surface of a straight steel pipe segment by manual shielded metal arc welding (SMAW) or by manual gas tungsten arc welding (GTAW). Thermocouples were used for measuring local temperatures at defined positions next to the weld seam. The influences of joint type, wall thickness of the sheet and pipe and heat input on the temperature distribution and, in particular, on the local peak temperatures and cooling rates were studied. Moreover, a finite element (FE) model of a selected weld configuration was created and validated for calculating the temperatures at positions that were inaccessible for direct measurements. The results of the measurements showed that the peak temperature at the inner surface of the pipe decreases with increasing wall thickness. However, independently from the wall thickness, the results of the simulations indicated austenitization next to the weld seam. The low cooling rates did not promote any martensite transformation, as confirmed by the moderate increase of the hardness and by microstructure characterization. The results are of practical interest for pipelines used to transport hydrogen gas, as the temperature-dependent composition of the microstructure and the temperature itself influence the absorption, diffusion and solubility of hydrogen in steel.
T2 - 78th IIW Annual Assembly and International Conference
CY - Genoa, Italy
DA - 22.06.2025
KW - Pipeline
KW - In-service welding
KW - Natural gas
KW - Hydrogen
KW - Component test
KW - Welding experiment
KW - Finite element simulation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659393
DO - https://doi.org/10.1007/s40194-026-02446-7
SN - 0043-2288
SP - 1
EP - 21
PB - Springer
CY - Berlin ; Heidelberg
AN - OPUS4-65939
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kühnel, Dana
A1 - Jemec Kokalj, Anita
A1 - Ramsperger, Anja F. R. M.
A1 - Drobne, Damjana
A1 - Undas, Anna
A1 - Potthoff, Annegret
A1 - Altmann, Korinna
A1 - Peijnenburg, Willie
A1 - Jeliazkova, Nina
A1 - Afanou, Anani Komlavi
A1 - Löder, Martin G. J.
A1 - Laforsch, Christian
A1 - Reuther, Rudolf
A1 - Giese, Bernd
T1 - Challenges in human micro- and nanoplastic risk assessment: stocktaking and the road ahead
N2 - Environmental hazards of micro- and nanoplastics (MNPs) and associated chemicals have been investigated for more than a decade. However, the field of human MNPs health risk assessment is still confronted by many uncertainties regarding exposure, fate, as well as the identification of potential health effects. Among others, the lack of reference test MNPs, natural particles as validated reference control, and toxicological test methods that are tailored for MNPs and specifically address the characteristic properties of MNPs, further contribute to data scarcity and hence complicate human risk assessment. Elucidating the complex relationship between MNPs and human health, from early life to adulthood, has been addressed by five European research projects. The aim of these projects organized within the European research cluster to understand the health impacts of MNPs (CUSP) was to provide reliable data regarding human exposure and hazard posed by MNPs. However, in view of the numerous properties of MNP, it is impossible to test all variants and the mixture of associated chemicals. Hence, pragmatic approaches are needed as substitute for experimental testing, including strategies to deal with data gaps and the associated uncertainties, whilst considering the specific properties of MNPs. In this work, partners from the CUSP projects PlasticsFatE and POLYRISK critically review and structure the data needs for human MNP risk assessment and propose options for prioritization to overcome the identified general and material-specific challenges. We identified six priority areas for future research, covering, (1) Quality assurance and quality control (QA/QC), 2) MNP material provision with various compositions and properties, (3) Appropriate control particles for toxicity testing, (4) Exposure and hazard assessment for plastic associated chemicals (incl. plastic additives), (5) Assessing the joint effects of MNP and associated chemicals, and (6) Characterization of functional biomarkers for MNP exposure and effect. These priority areas can be used to structure future research in the field.
KW - Microplastics
KW - Reference materials
KW - Nanoplastics
PY - 2026
DO - https://doi.org/10.1186/s12302-026-01376-x
SN - 2190-4715
SP - 1
EP - 32
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-65945
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lukowiak, M.C.
A1 - Wettmarshausen, Sascha
A1 - Hidde, Gundula
A1 - Landsberger, Petra
A1 - Boenke, Viola
A1 - Rodenacker, K.
A1 - Braun, Ulrike
A1 - Friedrich, Jörg Florian
A1 - Gorbushina, Anna
A1 - Haag, R.
T1 - Polyglycerol coated polypropylene surfaces for protein and bacteria resistance
N2 - Polyglycerol (PG) coated polypropylene (PP) films were synthesized in a two-step approach that involved plasma bromination and subsequently grafting hyperbranched polyglycerols with very few amino functionalities. The influence of different molecular weights and density of reactive linkers were investigated for the grafted PGs. Longer bromination times and higher amounts of linkers on the surface afforded long-term stability. The protein adsorption and bacteria attachment of the PP-PG films were studied. Their extremely low amine content proved to be beneficial for preventing bacteria attachment.
PY - 2015
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-325406
DO - https://doi.org/10.1039/c4py01375a
SN - 1759-9954
SN - 1759-9962
VL - 6
IS - 8
SP - 1350
EP - 1359
AN - OPUS4-32540
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goedecke, Caroline
A1 - Mülow-Stollin, Ulrike
A1 - Hering, S.
A1 - Richter, Janine
A1 - Piechotta, Christian
A1 - Paul, Andrea
A1 - Braun, Ulrike
T1 - A first pilot study on the sorption of environmental pollutants on various microplastic materials
N2 - With the drastic increase in plastic production, the input of plastic particles into the environment has become a recognised problem.
Xenobiotics are able to sorb to polymer materials, and this process is further enhanced where they Encounter microplastics (plastic fragments <5 mm). In this work we studied the sorption of metformin, a type-2 diabetes drug, and difenoconazole, a fungicide, onto the virgin polymer materials polyamide (PA), polypropylene (PP), and polystyrene (PS). Additionally, PP was cryo-milled and PA was treated with acid to investigate the influence of an increase in surface area and chemical modification. The material properties were also studied by dynamic scanning calorimetry (DSC), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). Sorption experiments were performed on the basis of a full factorial design examining the effect of agitation, pH value, and salinity. Experimental results showed that difenoconazole sorbs readily to all microplastics, whereas the more polar analyte metformin did not show any affinity to the materials used. For difenoconazole the governing factor in all cases is agitation, while both pH and salinity exhibited only a slight influence. The modification of polymers leads to enhanced sorption, indicating that an increase in surface area (cryo-milled PP) or inner volume (acid-treated PA) strongly favours adsorption. Moreover, long-term experiments demonstrated that the time until equilibrium is reached depends strongly on the particle size.
KW - Difenoconazole
KW - Metformin
KW - Plastic debris
KW - Polymer
KW - Dynamic scanning calorimetry
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402393
DO - https://doi.org/10.4172/2380-2391.1000191
SN - 2380-2391
VL - 4
IS - 1
SP - Article 1000191, 1
EP - 8
PB - Omics International
CY - Los Angeles
AN - OPUS4-40239
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kömmling, Anja
A1 - Chatzigiannakis, E.
A1 - Beckmann, Jörg
A1 - Wachtendorf, Volker
A1 - von der Ehe, Kerstin
A1 - Braun, Ulrike
A1 - Jaunich, Matthias
A1 - Schade, U.
A1 - Wolff, Dietmar
T1 - Discoloration Effects of High-Dose gamma-Irradiation and Long-Term Thermal Aging of (U) HMW-PE
N2 - Two polyethylene types with ultra-high (UHMWPE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60Co gammasource. Subsequently, thermal aging at 125∘C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Visspectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation.The discoloration of UHMW-PE disappeared again after thermal aging.Therefore, the yellowing is assumed to originate fromannealable color centers in the formof free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidantcontaining HMWPE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE.
KW - Irradiation
KW - UHMWPE
KW - Colour center
KW - Yellowness index
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-423992
DO - https://doi.org/10.1155/2017/1362491
SN - 1687-9422
VL - 2017
IS - Article ID 1362491
SP - 1
EP - 10
PB - Hindawi
AN - OPUS4-42399
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ressnig, A.
A1 - Corbiere, T.
A1 - Lunkenbein, T.
A1 - Braun, Ulrike
A1 - Willinger, M. G.
A1 - Antonietti, M.
T1 - Decomposition synthesis of tuneable, macroporous carbon foams from crystalline precursors via in situ templating
N2 - A flexible, sustainable, one-step thermal decomposition route for the synthesis of hierarchical, heteroatom doped carbon foams is presented. Task-specific semi-organic crystals combine functions for three different purposes: the carbon and heteroatom source, a foaming agent (CO2) and an in situ generable template (NaCl). Insights to the decomposition pathway were gained through FTIR/MS coupled TGA and an ultrafast out-of-furnace heating procedure and the products were analysed with (HR)SEM/TEM, EELS, FTIR, and N2 sorption. The resulting macroporous carbon foams are excellent supports for metallic nanoparticles due to their hierarchical structure, high surface area and tuneable heteroatom contents. This was demonstrated for catalytically active copper or the magnetic CoNi alloy for water purification.
KW - macroporous carbon
KW - thermal decomposition
KW - synthesize heteroatom
KW - in situ template (NaCl)
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-318641
DO - https://doi.org/10.1039/c4ta03646h
SN - 2050-7496
SN - 2050-7488
VL - 2
IS - 42
SP - 18076
EP - 18081
PB - RSC
CY - London [u.a.]
AN - OPUS4-31864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wesch, Ch.
A1 - Elert, Anna Maria
A1 - Wörner, M.
A1 - Braun, Ulrike
A1 - Klein, R.
A1 - Paulus, M.
T1 - Assuring quality in microplastic monitoring: About the value of clean-air devices as essentials for verified data
N2 - Avoiding aerial microfibre contamination of environmental samples is essential for reliable analyses when it comes to the detection of ubiquitous microplastics. Almost all laboratories have contamination problems which are largely unavoidable without investments in clean-air devices. Therefore, our study supplies an approach to assess background microfibre contamination of samples in the laboratory under particle-free air conditions. We tested aerial contamination of samples indoor, in a mobile laboratory, within a laboratory fume hood and on a clean bench with particles filtration during the examining process of a fish. The used clean bench reduced aerial microfibre contamination in our laboratory by 96.5%. This highlights the value of suitable clean-air devices for valid microplastic pollution data. Our results indicate, that pollution levels by microfibres have been overestimated and actual pollution levels may be many times lower. Accordingly, such clean-air devices are recommended for microplastic laboratory applications in future research work to significantly lower error rate
KW - Microplastics
KW - FTIR
KW - Quality
KW - Environmental Science
KW - Biological techniques
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-412402
DO - https://doi.org/10.1038/s41598-017-05838-4
SN - 2045-2322
VL - 7
SP - Article 5424, 1
EP - 8
PB - Nature
AN - OPUS4-41240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yalçin, M.
A1 - Taşçioğlu, C.
A1 - Plarre, Rüdiger
A1 - Akçay, Ç.
A1 - Busweiler, Sabine
T1 - Investigation of natural durability of some native and exotic wood species against Hylotrupes bajulus (Cerambycidae) and Anobium punctatum (Anobiidae)
N2 - Aim of study: In this study, natural durability of some domestic and foreign wood species against Hylotrupes bajulus and Anobium punctatum larvae were tested on laboratory scale
Area of study: This study was conducted at Department of Forest Products Engineering in Duzce University, Turkey and Federal Institute for Materials Research and Testing (BAM), Germany.
Material and Methods: Scotch pine (Pinus sylvestris), fir (Abies nordmanniana), spruce (Picea orientalis), cedar (Cedrus libani), poplar (Populus tremula) and beech (Fagus orientalis) woods were used to test H. bajulus larvae (EN 46-1). Alder (Alnus glutinosa), oak (Quercus cerris), poplar (Populus tremula), beech (Fagus orientalis), maple (Acer carpinifolium), ash (Fraxinus angustifolia), teak (Tectona grandis), ayous (Triplochiton scleroxylon), movingui (Distemonanthus benthamianus), dahoma (Piptadeniastrum africanum), iroko (Chlorophora excelsa), bubinga (Guibourtia tessmannii) and sapele (Entandrophragma cylindiricum) woods were used for A. punctatum larvae (EN 49-1). At the end of the experiment, the mortality rates of the larvae were determined and the size and weights of the surviving larvae were measured.
Main results: F. orientalis and C. libani were found to be the most resistant wood species against H. bajulus larvae while A. nordmanniana was the least resistant. All tropical wood species and oak and maple from domestic wood species showed 100% mortality rate therefore found to be the most resistant against A. punctatum larvae. The most vulnerable wood species was found to be alder with a 35% mortality.
Research highlights: while F. orientalis, C. libani, and P. tremula were found the most resistance wood species against H. bajulus, P. sylvestris and A. nordmanniana were determined as most vulnerable. All tropical wood species and two domestic species (Q. cerris and A. carpinifolium) showed the highest mortality rate as 100%. The least durable domestic wood was determined as alder.
KW - Hylotrupes bajulus, Anobium punctatum, natural durability, tropical wood, native wood.
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-446572
DO - https://doi.org/10.17475/kastorman.311971
SN - 1303-2399
SN - 1309-4181
VL - 18
IS - 1
SP - 83
EP - 91
PB - Kastamonu University
CY - Kastamonu
AN - OPUS4-44657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Oberpaul, M.
A1 - Zumkeller, C. M.
A1 - Culver, T.
A1 - Spohn, M.
A1 - Mihajlovic, S.
A1 - Leis, B.
A1 - Glaeser, S. P.
A1 - Plarre, Rüdiger
A1 - McMahon, Dino Peter
A1 - Hammann, P.
A1 - Schäberle, T. F.
A1 - Glaeser, J.
A1 - Vilcinskas, A.
T1 - High-Throughput Cultivation for the Selective Isolation of Acidobacteria From Termite Nests
N2 - Microbial communities in the immediate environment of socialized invertebrates can help to suppress pathogens, in part by synthesizing bioactive natural products. Here we characterized the core microbiomes of three termite species (genus Coptotermes) and their nest material to gain more insight into the diversity of termite-associated bacteria.
Sampling a healthy termite colony over time implicated a consolidated and highly stable microbiome, pointing toward the fact that beneficial bacterial phyla play a major role in termite fitness. In contrast, there was a significant shift in the composition of the core microbiome in one nest during a fungal infection, affecting the abundance of wellcharacterized Streptomyces species (phylum Actinobacteria) as well as less-studied bacterial phyla such as Acidobacteria. High-throughput cultivation in microplates was implemented to isolate and identify these less-studied bacterial phylogenetic group.
Amplicon sequencing confirmed that our method maintained the bacterial diversity of the environmental samples, enabling the isolation of novel Acidobacteriaceae and expanding the list of cultivated species to include two strains that may define new species within the genera Terracidiphilus and Acidobacterium.
KW - Termite-associated microbes
KW - Termites
KW - Coptotermes
KW - Core microbiome
KW - Natural products discovery
KW - Acidobacteria
KW - underexplored phyla
KW - Social insects
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515283
DO - https://doi.org/10.3389/fmicb.2020.597628
VL - 11
SP - 1
EP - 16
AN - OPUS4-51528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmann, Daniel
A1 - Eisentraut, Paul
A1 - Goedecke, Caroline
A1 - Wiesner, Yosri
A1 - Jekel, M
A1 - Ruhl, A S
A1 - Braun, Ulrike
T1 - Specific adsorption sites and conditions derived by thermal decomposition of activated carbons and adsorbed carbamazepine
N2 - The adsorption of organic micropollutants onto activated carbon is a favourable solution for the treatment of drinking water and wastewater. However, these adsorption processes are not sufficiently understood to allow for the appropriate prediction of removal processes. In this study, thermogravimetric analysis, alongside evolved gas analysis, is proposed for the characterisation of micropollutants adsorbed on activated carbon. Varying amounts of carbamazepine were adsorbed onto three different activated carbons, which were subsequently dried, and their thermal decomposition mechanisms examined. The discovery of 55 different pyrolysis products allowed differentiations to be made between specific adsorption sites and conditions. However, the same adsorption mechanisms were found for all samples, which were enhanced by inorganic constituents and oxygen containing surface groups. Furthermore, increasing the loadings led to the evolution of more hydrated decomposition products, whilst parts of the carbamazepine molecules were also integrated into the carbon structure. It was also found that the chemical composition, especially the degree of dehydration of the activated carbon, plays an important role in the adsorption of carbamazepine. Hence, it is thought that the adsorption sites may have a higher adsorption energy for specific adsorbates, when the activated carbon can then potentially increase its degree of graphitisation.
KW - Aktivkohle
KW - TED-GC/MS
KW - Adsorption
KW - Thermoanalytik
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506946
DO - https://doi.org/10.1038/s41598-020-63481-y
VL - 10
IS - 1
SP - 6695
PB - Nature Publishing Group
AN - OPUS4-50694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Topolniak, Ievgeniia
A1 - Hodoroaba, Vasile-Dan
A1 - Pfeifer, Dietmar
A1 - Braun, Ulrike
A1 - Sturm, Heinz
T1 - Boehmite Nanofillers in Epoxy Oligosiloxane Resins: Influencing the Curing Process by Complex Physical and Chemical Interactions
N2 - In this work, a novel boehmite (BA)-embedded organic/inorganic nanocomposite coating based on cycloaliphatic epoxy oligosiloxane (CEOS) resin was fabricated applying UV-induced cationic polymerization. The main changes of the material behavior caused by the nanofiller were investigated with regard to its photocuring kinetics, thermal stability, and glass transition. The role of the particle surface was of particular interest, thus, unmodified nanoparticles (HP14) and particles modified with p-toluenesulfonic acid (OS1) were incorporated into a CEOS matrix in the concentration range of 1–10 wt.%. Resulting nanocomposites exhibited improved thermal properties, with the glass transition temperature (Tg) being shifted from 30 °C for unfilled CEOS to 54 °C (2 wt.% HP14) and 73 °C (2 wt.% OS1) for filled CEOS. Additionally, TGA analysis showed increased thermal stability of samples filled with nanoparticles. An attractive interaction between boehmite and CEOS matrix influenced the curing. Real-time infrared spectroscopy (RT-IR) experiments demonstrated that the epoxide conversion rate of nanocomposites was slightly increased compared to neat resin. The beneficial role of the BA can be explained by the participation of hydroxyl groups at the particle surface in photopolymerization processes and by the complementary contribution of p-toluenesulfonic acid surface modifier and water molecules introduced into the system with nanoparticles.
KW - Real-time infrared spectroscopy
KW - Boehmite
KW - Nanocomposite
KW - Cationic photocuring
KW - Cycloaliphatic epoxy oligosiloxane
KW - Epoxy conversion degree
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479628
DO - https://doi.org/10.3390/ma12091513
VL - 12
IS - 9
SP - 1513
PB - MDPI
AN - OPUS4-47962
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vilcinskas, A.
A1 - Schwabe, M.
A1 - Brinkrolf, K.
A1 - Plarre, Rüdiger
A1 - Wielsch, N.
A1 - Vogel, H.
T1 - Larvae of the clothing moth Tineola bisselliella maintain gut bacteria that secrete enzyme cocktails to facilitate the digestion of keratin
N2 - The evolutionary success of insects is promoted by their association with beneficial microbes that enable the utilization of unusual diets. The synanthropic clothing moth Tineola bisselliella provides an intriguing example of this phenomenon. The caterpillars of this species have adapted to feed on keratin-rich diets such as feathers and wool, which cannot be digested by most other animals and are resistant to common digestive enzymes. Inspired by the hypothesis that this ability may be conferred by symbiotic microbes, we utilized a simple assay to detect keratinase activity and a method to screen gut bacteria for candidate enzymes, which were isolated from feather-fed larvae. The isolation of DNA from keratin-degrading bacterial strains followed by de novo genome sequencing resulted in the identification of a novel bacterial strain related to Bacillus sp. FDAARGOS_235. Genome Annotation identified 20 genes with keratinase domains. Proteomic analysis of the culture supernatant from this gut bacterium grown in non-nutrient buffer supplemented with feathers revealed several candidate enzymes potentially responsible for keratin degradation, including a thiol-disulfide oxidoreductase and multiple proteases. Our results suggest that the unusual diet of T. bisselliella larvae promotes their association with keratinolytic microorganisms and that the ability of larvae to feed on keratin can at least partially be attributed to bacteria that produce a cocktail of keratin-degrading enzymes.
KW - Keratin
KW - Insect biotechnology
KW - Beneficial microbes
KW - Symbiosis
KW - Dietary adaptation
KW - Tineola bisselliella
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512309
DO - https://doi.org/10.3390/microorganisms8091415
VL - 8
IS - 9
SP - 1415
PB - MDPI
AN - OPUS4-51230
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Haustein, T.
A1 - Busweiler, Sabine
A1 - Haustein, V.
A1 - von Laar, C.
A1 - Plarre, Rüdiger
T1 - Laboratory breeding of Korynetes caeruleus (Coleoptera: Cleridae) for the biological of Anobium punctatum) (Coleoptera, Ptinidae)
N2 - Larvae and adults of Korynetes caeruleus (de Geer 1775) (Coleoptera: Cleridae) were collected from old churches and reared in the laboratory on Anobium punctatum (de Geer 1774) (Coleoptera: Ptinidae). Breeding success of K. caeruleus was low, but basic parameters of this species’ developmental cycle were identifi ed. At 21°C and 75% relative humidity and a fourmonth cold period at 4°C, the development of K. caeruleus from egg to adult appearance lasted 2 years. The pupal stage may be reached and completed after one and a half years. Feeding on larvae of A. punctatum by larvae of K. caeruleus was observed and consisted of a combination of sucking haemolymph and consuming body parts. The sickle-like mandibles of larvae of K. caeruleus penetrate the cuticle of prey larvae; this is followed by pumping and sucking body movements. Adult beetles of A. punctatum were not attacked by K. caeruleus larvae. Feeding behaviour of adult K. caeruleus was not investigated.
KW - Cultural heritage
KW - Coleoptera
KW - Korynetes caeruleus
KW - Cleridae
KW - Ptinidae
KW - Anobium punctatum
KW - Biological pest control
KW - Life history data
KW - Laboratory breeding
KW - Wood protection
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494999
DO - https://doi.org/10.14411/eje.2019.038
SN - 1802-8829
VL - 116
SP - 362
EP - 371
PB - České Budějovice
AN - OPUS4-49499
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Söftje, M.
A1 - Acker, S.
A1 - Plarre, Rüdiger
A1 - Namyslo, J. C.
A1 - Kaufmann, D. E.
T1 - Novel nicotinoid structures for covalent modification of wood: an environmentally friendly way for its protection against insects
N2 - Timber is constantly exposed to environmental influences under outdoor conditions which limits its Lifetime and usability. In order to counteract the damaging processes caused by insects, we have developed a novel and more environmentally friendly method to protect wood materials via covalent modification by organic insecticides. Starting with an important class of synthetic insecticides which are derived from the natural insecticide nicotine, various new carboxylic acid derivatives of imidacloprid were made accessible. These activated neonicotinoids were utilized for the chemical modification of wood hydroxy groups. In contrast to conventional wood preservation methods in which biocides are only physically bound to the surface for a limited time, the covalent fixation of the preservative guarantees a permanent effect against wood pests, demonstrated in standardized biological tests. Additionally, the environmental interaction caused by non-bound neonicotinoids is significantly reduced, since both, a smaller application rate is required and leaching of the active ingredient is prevented. By minimizing the pest infestation, the lifetime of the material increases while preserving the natural appearance of the material.
KW - Environment
KW - Wood Protection
KW - Efficacy
KW - Insecticide
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506856
DO - https://doi.org/10.1039/d0ra02071k
VL - 10
SP - 15726
EP - 15733
AN - OPUS4-50685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Usmani, Shirin M.
A1 - Plarre, Rüdiger
A1 - Hübert, Thomas
A1 - Kemnitz, E.
ED - Richter, K.
ED - Van de Kulien, J.-W.
T1 - Termite resistance of pine wood treated with nano metal fluorides
N2 - Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect wood from termite attack.
KW - Holzschutzmittel
KW - Nanoparticles
KW - Fluorides
KW - Termites
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-514325
DO - https://doi.org/10.1007/s00107-020-01522-z
VL - 78
SP - 493
EP - 499
PB - Springer
CY - Berlin
AN - OPUS4-51432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Usmani, Shirin M.
A1 - Plarre, Rüdiger
A1 - Hübert, Thomas
A1 - Kemnitz, E.
T1 - Termite resistance of pine wood treated with nano metal fluorides
N2 - Fluorides are well-known as wood preservatives. One of the limitations of fluoride-based wood preservatives is their high leachability. Alternative to current fluoride salts such as NaF used in wood protection are low water-soluble fluorides. However, impregnation of low water-soluble fluorides into wood poses a challenge. To address this challenge, low water-soluble fluorides like calcium fluoride (CaF2) and magnesium fluoride (MgF2) were synthesized as nanoparticles via the fluorolytic sol−gel synthesis and then impregnated into wood specimens. In this study, the toxicity of nano metal fluorides was assessed by termite mortality, mass loss and visual analysis of treated specimens after eight weeks of exposure to termites, Coptotermes formosanus. Nano metal fluorides with sol concentrations of 0.5 M and higher were found to be effective against termites resulting in 100% termite mortality and significantly inhibited termite feeding. Among the formulations tested, the least damage was found for specimens treated with combinations of CaF2 and MgF2 with an average mass loss less than 1% and visual rating of “1”. These results demonstrate the efficacy of low water-soluble nano metal fluorides to protect Wood from termite attack.
KW - Wood Protection
KW - Nano Particles
KW - Termites
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508377
DO - https://doi.org/10.1007/s00107-020-01522-z
VL - 78
SP - 493
EP - 499
PB - Springer
AN - OPUS4-50837
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chinellato, Fabio
A1 - Wilbig, Janka
A1 - Al-Sabbagh, Dominik
A1 - Colombo, P.
A1 - Günster, Jens
T1 - Gas flow assisted powder deposition for enhanced flowability of fine powders: 3D printing of alpha-tricalcium phosphate
N2 - The possibility of creating patient-specific individual implants makes Additive Manufacturing technologies of special interest for the medical sector. For substitution of bone defects, powder based Additive Manufacturing by Binder Jetting is a suitable method to produce complex scaffold-like structures made of bioceramics with easily adapted geometries and controlled porosity. The process inherent residual porosity in the printed part, even though desired as it supports bone ingrowth, also leads to limited mechanical strength. Currently, bioceramic scaffolds made by Binder Jetting feature suitable biocompatible and biodegradable properties, while a sufficient mechanical stability is rather challenging. The purpose of this work is to apply the gas flow assisted powder deposition introduced in 2014 by Zocca et al., to the powder bed during printing of bioceramic tablets and scaffolds using α-TCP powder as feedstock. This enables exploiting the advantages of an increased powder bed density, thereby improving the mechanical properties of the printed parts.
KW - Additive Manufacturing
KW - Binder Jetting
KW - Gas flow assisted powder deposition
KW - Alpha-tricalcium phosphate
KW - Scaffold
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510138
DO - https://doi.org/10.1016/j.oceram.2020.100003
SN - 2666-5395
VL - 1
SP - 100003
PB - Elsevier Ltd.
AN - OPUS4-51013
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Getenet, M.
A1 - Otálora, F.
A1 - Emmerling, Franziska
A1 - Al-Sabbagh, Dominik
A1 - García-Ruiz, J. M.
T1 - Mineral precipitation and hydrochemical evolution through evaporitic processes in soda brines (East African Rift Valley)
N2 - Soda lakes of the East African Rift Valley are hyperalkaline, hypersaline lakes extremely enriched in Na+, K+, Cl−, CO32−, HCO3−, and SiO2. In this paper, we investigate the chemical evolution in these lakes and the production of chemical sediments by salt precipitation via evaporation. Water samples from tributary springs and three lakes (Magadi, Nasikie Engida and Natron) have been experimentally studied by in-situ X-ray diffraction during evaporation experiments to characterize the sequence of mineral precipitation. These data are complemented by ex-situ diffraction studies, chemical analyses and thermodynamic hydrochemical calculations producing detailed information on the activity of all solution species and the saturation state of all minerals potentially generated by the given composition. Major minerals precipitating from these samples are sodium carbonates/bicarbonates as well as halite. The CO3/HCO3 ratio, controlled by pH, is the main factor defining the Na‑carbonates precipitation sequence: in lake brines where CO3/HCO3 > 1, trona precipitates first whereas in hot springs, where CO3/HCO3 ≪ 1, nahcolite precipitates instead of trona, which forms later via partial dissolution of nahcolite. Precipitation of nahcolite is possible only at lower pH values (pCO2 higher than −2.7) explaining the distribution of trona and nahcolite in current lakes and the stratigraphic sequences. Later, during evaporation, thermonatrite precipitates, normally at the same time as halite, at a very high pH (>11.2) after significant depletion of HCO3− due to trona precipitation. The precipitation of these soluble minerals increases the pH of the brine and is the main factor contributing to the hyperalkaline and hypersaline character of the lakes. Villiaumite, sylvite, alkaline earth carbonates, fluorapatite and silica are also predicted to precipitate, but most of them have not been observed in evaporation experiments, either because of the small amount of precipitates produced, kinetic effects delaying the nucleation of some phases, or by biologically induced effects in the lake chemistry that are not considered in our calculations. Even in these cases, the chemical composition in the corresponding ions allows for discussion on their accumulation and the eventual precipitation of these phases. The coupling of in-situ and ex-situ experiments and geochemical modelling is key to understanding the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and other extraterrestrial bodies.
KW - Crystallization sequence
KW - Hydrochemical evolution
KW - Alkaline brines
KW - Sodium carbonate minerals
KW - Soda lakes
KW - Evaporite deposits
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-568431
DO - https://doi.org/10.1016/j.chemgeo.2022.121222
SN - 0009-2541
VL - 616
SP - 1
EP - 13
PB - Elsevier
CY - New York, NY
AN - OPUS4-56843
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwabe, M.
A1 - Griep, S.
A1 - Schmidtberg, H.
A1 - Plarre, Rüdiger
A1 - Goesmann, A.
A1 - Vilcinskas, A.
A1 - Vogel, H.
A1 - Brinkrolf, K.
T1 - Next-Generation Sequencing Analysis of the Tineola bisselliella Larval Gut Transcriptome Reveals Candidate Enzymes for Keratin Digestion
N2 - The clothes moth Tineola bisselliella is one of a few insects that can digest keratin, leading to the destruction of clothing, textiles and artwork. The mechanism of keratin digestion is not yet fully understood, partly reflecting the lack of publicly available genomic and transcriptomic data. Here we present a high-quality gut transcriptome of T. bisselliella generated from larvae reared on keratin-rich and keratin-free diets. The overall transcriptome consists of 428,221 contigs that were functionally annotated and screened for candidate enzymes involved in keratin utilization. As a mechanism for keratin digestion, we identified cysteine synthases, cystathionine β-synthases and cystathionine γ-lyases. These enzymes release hydrogen sulfite, which may reduce the disulfide bonds in keratin. The dataset also included 27 differentially expressed contigs with trypsin domains, among which 20 were associated with keratin feeding. Finally, we identified seven collagenases that were upregulated on the keratin-rich diet. In addition to this enzymatic repertoire potentially involved in breaking down keratin, our analysis of poly(A)-enriched and poly(A)-depleted transcripts suggested that T. bisselliella larvae possess an unstable intestinal microbiome that may nevertheless contribute to keratin digestion
KW - Insect biotechnology
KW - Gene expression
KW - RNA-Sequencing
KW - Transcriptomics
KW - Tineola bisselliella
KW - Keratin
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529902
DO - https://doi.org/10.3390/genes12081113
VL - 12
IS - 8
SP - 1113
PB - MDPI
AN - OPUS4-52990
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Söftje, M.
A1 - Weingartz, T.
A1 - Plarre, Rüdiger
A1 - Gjikaj, M.
A1 - Namysko, J. C.
A1 - Kaufmann, D. E.
T1 - Surface Tuning of Wood via Covalent Modification of Its Lignocellulosic Biopolymers with Substituted BenzoatesA Study on Reactivity, Efficiency, and Durability
N2 - Chemical modification of wood applying benzotriazolyl-activated carboxylic acids has proven to be a versatile method for the durable functionalization of its lignocellulosic biopolymers. Through this process, the material properties of Wood can be influenced and specifically optimized. To check the scope and limitations of this modification method, various benzamide derivatives with electron-withdrawing (EWG) or electron-donating (EDG) functional groups in different positions of the aromatic ring were synthesized and applied for covalent modification of Scots pine (Pinus sylvestris L.) sapwood in this study. The bonded amounts of substances (up to 2.20 mmol) were compared with the reactivity constants of the Hammett equation, revealing a significant correlation between the modification efficiency and the theoretical reactivity constants of the corresponding aromatic substitution pattern. The successful covalent attachment of the respective substituted benzamides was proven by attenuated total reflection infrared (ATR-IR) spectroscopy, while the stability of the newly formed ester bond was proven in a standardized leaching test.
KW - Leaching
KW - Wood Protection
KW - Wood Modification
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538932
DO - https://doi.org/10.1021/acsomega.1c04353
VL - 6
IS - 49
SP - 33542
EP - 33553
AN - OPUS4-53893
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abdallah, Khaled
A1 - Stock, S. C.
A1 - Heeger, Felix
A1 - Koester, M.
A1 - Nájera, F.
A1 - Merino, C.
A1 - Spielvogel, S.
A1 - Gorbushina, Anna
A1 - Kuzyakov, Y.
A1 - Dippold, M. A.
T1 - Nitrogen Gain and Loss Along an Ecosystem Sequence: From Semi-desert to Rainforest
N2 - Plants and microorganisms, besides the climate, drive nitrogen (N) cycling in ecosystems. Our objective was to investigate N losses and N acquisition strategies along a unique ecosystem-sequence (ecosequence) ranging from arid shrubland through Mediterranean woodland to temperate rainforest. These ecosystems differ in mean annual precipitation, mean annual temperate, and vegetation cover, but developed on similar granitoid soil parent material, were addressed using a combination of molecular biology and soil biogeochemical tools. Soil N and carbon (C) contents, δ15N signatures, activities of N acquiring extracellular enzymes as well as the abundance of soil bacteria and fungi, and diazotrophs in bulk topsoil and rhizosphere were determined. Relative fungal abundance in the rhizosphere was higher under woodland and forest than under shrubland. This indicates toward plants' higher C investment into fungi in the Mediterranean and temperate rainforest sites than in the arid site. Fungi are likely to decompose lignified forest litter for efficient recycling of litter-derived N and further nutrients. Rhizosphere—a hotspot for the N fixation—was enriched in diazotrophs (factor 8 to 16 in comparison to bulk topsoil) emphasizing the general importance of root/microbe association in N cycle. These results show that the temperate rainforest is an N acquiring ecosystem, whereas N in the arid shrubland is strongly recycled. Simultaneously, the strongest 15N enrichment with decreasing N content with depth was detected in the Mediterranean woodland, indicating that N mineralization and loss is highest (and likely the fastest) in the woodland across the continental transect. Higher relative aminopeptidase activities in the woodland than in the forest enabled a fast N mineralization. Relative aminopeptidase activities were highest in the arid shrubland. The highest absolute chitinase activities were observed in the forest. This likely demonstrates that (a) plants and microorganisms in the arid shrubland invest largely into mobilization and reutilization of organically bound N by exoenzymes, and (b) that the ecosystem N nutrition shifts from a peptide-based N in the arid shrubland to a peptide- and chitin-based N nutrition in the temperate rainforest, where the high N demand is complemented by intensive N fixation in the rhizosphere.
KW - Nitrogen
KW - Rhizosphere
KW - Microbial abundance
KW - Natural abundance of 15N
KW - Nitrogen fixation
KW - Nitrogen uptake
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543708
DO - https://doi.org/10.3389/fsoil.2022.817641
SN - 2673-8619
VL - 2
SP - 1
EP - 14
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-54370
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Esparza Mora, Margy Alejandra
A1 - Davis, H. E.
A1 - Meconcelli, Stefania
A1 - McMahon, Dino Peter
A1 - Plarre, Rüdiger
T1 - Inhibition of a secreted immune molecule interferes with termite social immunity
N2 - Social immune behaviors are described in a great variety of insect societies and their role in preventing emerging infectious diseases has become a major topic in insect research. The social immune system consists of multiple layers, ranging from the synthesis of external immune molecules to the coordination of individual behaviors into sophisticated collective defensive tasks. But our understanding of how complex group-level behavioral defenses are orchestrated has remained limited. We sought to address this gap in knowledge by investigating the relationship between the external activity of an important immune effector molecule in termites, Gram negative binding protein 2 (GNBP-2) and collective grooming and cannibalism. We reasoned that as an external enzyme capable of degrading entomopathogenic fungi, GNBP-2 can facilitate the spread of pathogenic molecules in the colony, and thus serve to trigger collective defenses in a manner analogous to pathogen-associated molecular signatures (PAMPs) of the individual immune system. To test whether GNBP-2 could play a role in regulating social immune behavior, we experimentally inhibited its fungicidal activity using the glycomimetic molecule, D-d-gluconolactone (GDL) and recorded collective behavioral responses to an infected nestmate. Contrary to expectations, GNBP-2 inhibition did not influence the rate or intensity of grooming of either control or fungus-infected
nestmates. By contrast, we found that the probability of being harmed through defensive cannibalistic behaviors was significantly reduced by the inhibition of GNBP-2. Our findings indicate that the regulation of collective immune behaviors may depend in part on the external secretion of an enzyme originating from the individual immune system, but that other cues are also necessary.
KW - Entomopathogen
KW - Termite
KW - Social immunity
KW - Cannibalism
KW - GNBP-2
KW - Hygienic behavior
KW - GDL
KW - Metarhizium
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-520037
DO - https://doi.org/10.3389/fevo.2020.00075
SN - 2296-701X
VL - 8
SP - 1
EP - 10
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-52003
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wander, Lukas
A1 - Lommel, Lukas
A1 - Meyer, Klas
A1 - Braun, Ulrike
A1 - Paul, Andrea
T1 - Development of a low-cost method for quantifying microplastics in soils and compost using near-infrared spectroscopy
N2 - Near-infrared (NIR) spectroscopy is a promising candidate for low-cost, nondestructive, and high-throughput mass quantification of micro¬plastics in environmental samples. Widespread application of the technique is currently hampered mainly by the low sensitivity of NIR spectroscopy compared to thermo-analytical approaches commonly used for this type of analysis. This study shows how the application of NIR spectroscopy for mass quantification of microplastics can be extended to smaller analyte levels by combining it with a simple and rapid microplastic enrichment protocol. For this purpose, the widely used flotation of microplastics in a NaCl solution, accelerated by centrifugation, was chosen which allowed to remove up to 99 % of the matrix at recovery rates of 83–104 %. The spectroscopic measurements took place directly on the stainless-steel filters used to collect the extracted particles to reduce sample handling to a minimum. Partial least squares regression (PLSR) models were used to identify and quantify the extracted microplastics in the mass range of 1–10 mg. The simple and fast extraction procedure was systematically optimized to meet the requirements for the quantification of microplastics from common PE-, PP-, and PS-based packaging materials with a particle size < 1 mm found in compost or soils with high natural organic matter content (> 10 % determined by loss on ignition). Microplastics could be detected in model samples at a mass fraction of 1 mg g-1. The detectable microplastic mass fraction is about an order of magnitude lower compared to previous studies using NIR spectroscopy without additional enrichment. To emphasize the cost-effectiveness of the method, it was implemented using some of the cheapest and most compact NIR spectrometers available.
KW - NIR
KW - Soil
KW - compost
KW - PLSR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546405
DO - https://doi.org/10.1088/1361-6501/ac5e5f
SN - 0957-0233
VL - 33
IS - 7
SP - 075801
EP - 075814
PB - IOP Publishing Ltd.
CY - UK
AN - OPUS4-54640
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wander, Lukas
A1 - Lommel, Lukas
A1 - Braun, Ulrike
A1 - Meyer, Klas
A1 - Paul, Andrea
T1 - Development of a Low-Cost Method for Quantifying Microplastics in Soils and Compost Using Near-Infrared Spectroscopy
N2 - Near-infrared (NIR) spectroscopy is a promising candidate for low-cost, nondestructive, and highthroughput mass quantification of microplastics in environmental samples. Widespread application of the technique is currently hampered mainly by the low sensitivity of NIR spectroscopy compared to thermoanalytical approaches commonly used for this type of analysis. This study shows how the application of NIR spectroscopy for mass quantification of microplastics can be extended to smaller analyte levels by combining it with a simple and rapid microplastic enrichment protocol. For this purpose, the widely used flotation of microplastics in a NaCl solution, accelerated by centrifugation, was chosen which allowed to remove up to 99 % of the matrix at recovery rates of 83–104 %. The spectroscopic measurements took place directly on the stainless-steel filters used to collect the extracted particles to reduce sample handling to a minimum. Partial least squares regression (PLSR) models were used to identify and quantify the extracted microplastics in the mass range of 1–10 mg.
The simple and fast extraction procedure was systematically optimized to meet the requirements for the quantification of microplastics from common PE-, PP-, and PS-based packaging materials with a particle size < 1 mm found in compost or soils with high natural organic matter content (> 10 % determined by loss on ignition). Microplastics could be detected in model samples at a mass fraction of 1 mg g-1. The detectable microplastic mass fraction is about an order of magnitude lower compared to previous studies using NIR spectroscopy without additional enrichment. To emphasize the cost-effectiveness of the method, it was implemented using some of the cheapest and most
compact NIR spectrometers available.
KW - Mikroplastik
KW - NIR
KW - Sensor
KW - Kompost
KW - Multivariat
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552605
DO - https://doi.org/10.1088/1361-6501/ac5e5f
VL - 33
IS - 7
SP - 1
EP - 13
PB - IOP Publishing Ltd.
CY - Bristol
AN - OPUS4-55260
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Röder, Bettina
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point.
Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools.
KW - Mechanochemistry
KW - Kinetics
KW - In situ
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-558878
DO - https://doi.org/10.1039/d2fd00115b
SP - 1
EP - 16
PB - Royal Society of Chemistry
AN - OPUS4-55887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Waniek, Tassilo
A1 - Braun, Ulrike
A1 - Silbernagl, Dorothee
A1 - Sturm, Heinz
T1 - The impact of water released from boehmite nanoparticles during curing in epoxy-based nanocomposites
N2 - The enhancing effect on mechanical properties of boehmite (γ-AlOOH) nanoparticles (BNP) in epoxy-based nanocomposites on the macroscopic scale encouraged recent research to investigate the micro- and nanoscopic properties. Several studies presented different aspects relatable to an alteration of the epoxy polymer network formation by the BNP with need for further experiments to identify the mode of action.
With FTIR-spectroscopic methods this study identifies interactions of the BNP with the epoxy polymer matrix during the curing process as well as in the cured nanocomposite. The data reveals that not the BNP themselves, but the water released from them strongly influences the curing process by hydrolysis of the anhydride hardener or protonation of the amine accelerator. The changes of the curing processes are discussed in detail.
The changes of the curing processes enable new explanation for the changed material properties by BNP discussed in recent research like a lowered glass transition temperature region (Tg) and an interphase formation.
KW - Spectroscopy
KW - Aluminium oxide hydroxide
KW - Glass transition temperature
KW - Material chemistry
KW - Nanocomposites
KW - Structure-property relationship
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527202
DO - https://doi.org/10.1002/app.51006
VL - 138
IS - 39
SP - 51006
PB - Wiley Periodicals LLC
CY - Hoboken
AN - OPUS4-52720
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - de Moraes, M. C.
A1 - Durlo Tambara, Luís Urbano
A1 - Cheriaf, M.
A1 - Rocha, J. C.
T1 - The influence of relative humidity on drying shrinkage mechanisms in hybrid alkaline systems with bottom ash and rice husk ash
N2 - This study investigated the influence of relative humidity (RH = 30%, 60 %, and 90 %) on the drying shrinkage behaviour of hybrid alkaline cement (HAC) systems, composed of 30 % Portland cement and 70 % bottom ash (BA) and/or rice husk ash (RHA). At RH < 30 %, HAC mortars exhibited shrinkage strains up to 7 times higher than Portland cement, whereas curing at RH > 90 % reduced shrinkage by nearly 15-fold compared to dry conditions. The 70RHA mixture demonstrated the highest shrinkage under low RH, associated with its refined micropore structure and elevated internal surface area. Nitrogen adsorption-desorption analysis revealed that low RH hindered pore refinement, while wet curing promoted gel densification, increasing the fraction of pores below 5 nm and improving compressive strength. At intermediate RH, mesopore volume increased after 28 days, consistent with microstructural changes associated with moisture exchange processes. This work provides a combined analysis of humidity-dependent shrinkage mechanisms and pore structure evolution in hybrid alkaline systems incorporating industrial and agricultural residues. The main contribution lies in identifying two distinct shrinkage regimes governed by pore-scale mechanisms under different RH conditions, offering practical guidance for curing optimisation and dimensional stability control in sustainable cementitious materials.
KW - Alkali activation
KW - Hybrid alkaline cement
KW - Bottom ash
KW - Rice husk ash
KW - Drying shrinkage
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659064
DO - https://doi.org/10.1016/j.rineng.2026.110206
SN - 2590-1230
VL - 30
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65906
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, Hans R.
A1 - Weidner, Steffen
A1 - Meyer, Andreas
A1 - Buijsen, Paul
T1 - Poly(trimethylene terephthalate) − solid state polycondensation and the formation of monodisperse Extended-Ring crystals
N2 - Linear, low-molar-mass poly(trimethylene terephthalate) (PTT) was synthesized via the polycondensation of 1,3-propanediol and dimethyl terephthalate and investigated by matrix-assisted laser desorption/ionization time of flight (MALDI TOF) mass spectrometry, size exclusion chromatography (SEC), differential scanning calorimetry (DSC) and x-ray scattering. The obtained PTT was used in crystalline plaque or powder form for studies of its solid-state polycondensation (SSP). The combination of powder and vacuum increased the number-average molecular weight (Mn) by a factor of three. Interestingly, even-numbered cycles with degrees of polymerization (DPs) between six and 16 were preferentially formed. Annealing after doping with tin catalysts produced three cyclic main reaction products (C10, C12 and C14), which suggest that thermodynamic control of transesterification processes favors the formation of three types of monodisperse extended-ring crystallites (ERC) with thicknesses of 5, 6 of 7 repeat units. Additionally, a predominantly cyclic PTT was prepared, once again demonstrating the formation of even-numbered ERC upon annealing. Crystallinities calculated from WAXS measurements showed satisfactory agreement with those determined by DSC. SAXS measurements confirmed that the crystal thickness defined by ERC is also valid for long chains and large cycles that crystallize with chain folding.
KW - MALDI-TOF MS
KW - Polycondensation
KW - Crystallisation
KW - Poly(trimethylene terephthalate)
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659071
DO - https://doi.org/10.1016/j.eurpolymj.2026.114716
SN - 0014-3057
VL - 252
SP - 1
EP - 10
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-65907
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittrich, Tim
A1 - Jansen, Daniel
A1 - Weise, Frank
A1 - Stelzner, Ludwig
A1 - Dehn, Frank
T1 - Thermal decomposition in blended cement systems and its effect on fire-inducedconcrete spalling: Insights from XRD and TGA
N2 - Blended cements are gaining increasing popularity due to their lower CO2-footprint in compar-ison to ordinary Portland cement (OPC). However, this growing use raises the potential risk of buildings made with blended cement concrete being exposed to fire,which can lead to heavy damages caused by explosive concrete spalling. It has already been shown that the cement type strongly influences the fire-induced concrete spalling and the thermally induced moisture transport, however, to understand the mechanisms behind these findingsthe thermal decompo-sition behavior of the cementitious matrix must be investigated more systematically. Therefore, the phase content of three blended cement pastes (CEM II/A-LL, CEM III/A and CEM II/B-Q) was studied in comparison with a Portland cement paste (CEM I) after temperature exposure to 20 ◦C, 105 ◦C, 300 ◦C and 500 ◦C. Clear differences in the initial phase composition and their dehy-dration behavior between the individual cement types were recognized. In conclusion, blended cements showed lower amounts of AFt and AFm phases and additionally lower amounts of portlandite and C-(A)-S-H were found in CEM III/A and CEM II/B-Q pastes. The results suggest that higher AFt and AFm contents in CEM I, which are associated with greater water release at relatively low temperatures may ultimately reduce the spalling risk. Furthermore, C-(A)-S-H in CEM III/A and CEM II/B-Q showed increased thermal stability and large amounts of non-hydrated phases were found in every blended cement paste. Both of those aspects might contribute to thermomechanical spalling and the overall increased spalling susceptibility observed in blended cement concrete.
KW - Fire concrete spalling
KW - High temperatures
KW - Blended cements
KW - Dehydration
KW - XRD
KW - TGA
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659021
DO - https://doi.org/10.1016/j.cscm.2026.e05784
SN - 2214-5095
VL - 24
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam [u.a.]
AN - OPUS4-65902
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation of the Extrapolation Capability of an Artificial Neural Network Algorithm in Combination with Process Signals in Resistance Spot Welding of Advanced High-Strength Steels
N2 - Resistance spot welding is an established joining process for the production of safetyrelevant components in the automotive industry. Therefore, consecutive process monitoring is essential to meet the high quality requirements. Artificial neural networks can be used to evaluate the process parameters and signals, to ensure individual spot weld quality. The predictive accuracy of such algorithms depends on the provided training data set, and the prediction of untrained data is challenging. The aim of this paper was to investigate the extrapolation capability of a multi-layer perceptron model. That means, the predictive performance of the model was tested with data that clearly differed from the training data in terms of material and coating composition. Therefore, three multi-layer perceptron regression models were implemented to predict the nugget diameter from process data. The three models were able to predict the training datasets very well. The models, which were provided with features from the dynamic resistance curve predicted the new dataset better than the model with only process parameters. This study shows the beneficial influence of process signals on the predictive accuracy and robustness of artificial neural network algorithms.
Especially, when predicting a data set from outside of the training space.
KW - Automotive
KW - Artificial intelligence
KW - Quality monitoring
KW - Resistance spot welding
KW - Quality assurance
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539783
DO - https://doi.org/10.3390/met11111874
VL - 11
IS - 11
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-53978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Schmidt, Jonathan
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Olbricht, Jürgen
A1 - Jokisch, T.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation on seam quality and fatigue crack propagation in electron beam welded additive manufactured Inconel 939
N2 - Laser powder bed fusion of metals (PBF-LB/M) offers great potential for the production of new and spare parts for stationary gas turbines made of nickel superalloys such as Inconel 939 (IN939). In order to enable integration into existing assemblies and overcome design limitations, the additive manufacturing process chain must be expanded by suitable joining techniques. This study compares the electron beam welding of cast IN939 sheets and sheets produced additively using PBF-LB/M. The investigation focuses on the achievable seam quality with regard to geometric irregularities and internal defects in the form of liquation cracks on the microscale in the heat-affected zone. The evaluation of the welded samples shows no differences in the formation of the seam shape between the additively manufactured material and the cast material. For both materials, the highest quality category for beam-welded seams according to DIN EN ISO 13,919–1 was achieved at high welding speeds of 20 mm/s. Regardless of the manufacturing method, both materials show an increase in crack formation with increasing welding speed. However, due to its microstructure, the PBF-LB/M material exhibits significantly fewer microcracks overall. Final crack propagation tests on welded PBF-LB/M samples that were treated using HIP also show stable crack growth without sudden failure, which opens up potential for practical application.
KW - Electron beam welding
KW - Inconel 939
KW - PBF-LB/M
KW - Liquation cracking
KW - Fatigue crack propagation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657015
DO - https://doi.org/10.1016/j.jajp.2026.100389
SN - 2666-3309
VL - 13
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-65701
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Huo, Wenjie
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, Katinka
T1 - An illumination based backdoor attack against crack detection systems in laser beam welding
N2 - Deep neural networks (DNNs) have been wildly used in engineering and have achieved state-of-the-art performance in prediction and measurement tasks. A solidification crack is a serious fault during laser beam welding and it has been proven to be successfully detected using DNNs. Recently, research on the security of DNNs is receiving increasing attention because it is necessary to explore the reliability of DNNs to avoid potential security risks. The backdoor attack is a serious threat, where attackers aim to inject an inconspicuous pattern referred to as trigger into a small portion of training data, resulting in incorrect predictions in the reference phase whenever the input contains the trigger. In this work, we first generate experimental data containing actual cracks in the welding laboratory for training a crack detection model. Then, targeting this scenario, we design a new type of backdoor attack to induce the model to predict the crack as a normal state. Considering the stealthiness of the attack, a common phenomenon during the welding process, illumination, is used as the backdoor trigger. Experimental results demonstrate that the proposed method can successfully attack the crack detection system and achieve over 90% attack success rate on the test set.
T2 - 8th ML4CPS 2025 – Machine Learning for Cyber-Physical Systems
CY - Berlin, Germany
DA - 06.03,2025
KW - System security
KW - Welding crack detection
KW - Backdoor attack
KW - Deep neural networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651357
DO - https://doi.org/10.24405/20021
VL - 2025
SP - 12
EP - 21
PB - Universitätsbibliothek der HSU/UniBw H
CY - Hamburg
AN - OPUS4-65135
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huo, Wenjie
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, Katinka
T1 - Prediction of mean strain from laser beam welding images and detection of defects via strain curves based on machine learning
N2 - With the advancement of machine learning, many predictions and measurements in visual tasks can be achieved by convolutional neural networks (CNNs). Solidification hot cracking is a significant defect in laser beam welding, commonly encountered in practical applications. Existing theories indicate that the formation of cracks is closely related to strain accumulation near the solidification front. In this paper, we first leverage supervised Regression networks to design CNNs that achieve real-time average strain estimation for each frame in the collected welding videos. Two different architectures are proposed and compared: the first model stacks two frames at a set interval and feeds them into the network, while the second model extracts image features individually and predicts the results by calculating the correlation between them. Each network has its own advantages in Terms of computational efficiency and accuracy. Finally, we further train a multilayer perceptron (MLP) classification model that can detect the occurrence of cracks based on the predicted strain behaviors.
KW - Laser beam welding
KW - Mean strain prediction
KW - Solidification cracking detection Convolutional neural networks
KW - Convolutional neural networks
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-644495
DO - https://doi.org/10.1016/j.optlastec.2025.113975
SN - 0030-3992
VL - 192, Part F
SP - 1
EP - 8
PB - Elsevier Ltd.
AN - OPUS4-64449
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Arc-sidewall-attaching-driven control of swing arc motion in narrow gap GMAW
N2 - A novel, event-driven approach to controlling the weaving motion in swing arc narrow gap GMAW is presented in this study. The control method is based on independently detecting the arc attachment event at each sidewall of the narrow groove to adjust the weaving motion in real time. Previous arc sensing approaches for swing arc principles are based on evaluating and comparing arc sensor readings collected during the dwell periods at each sidewall. Not only does this require the torch to be positioned at the groove centre and the arc motion to be symmetric, but previous methods have also been shown to rely on complex parametrization of control parameters. The newly presented approach is based on the real-time monitoring of the welding current progression during the approach of the arc towards the sidewall of the groove independently on each side. As soon as the arc attachment at the sidewall is detected based on a characteristic rise in the current signal, the weaving motion is stopped. For reference experiments in a 21-mm wide groove, the weaving angle amplitude is controlled and limited to 50° on both sides individually, resulting in stable process conditions and uniform sidewall fusion. It is further shown that the newly developed control method can successfully be applied to groove widths of 18 mm and 24 mm without reconfiguration of the control parameters, highlighting the flexibility of the approach.
KW - Gas metal arc welding
KW - Narrow gap
KW - Arc sensor
KW - Control
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647640
DO - https://doi.org/10.1007/s40194-025-02238-5
SN - 0043-2288
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
AN - OPUS4-64764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Kising, Pascal
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Prediction of weld pool and keyhole geometries in high-power laser beam welding through a physics-informed generative artificial intelligence approach
N2 - The weld pool and keyhole geometries are critical characteristics in evaluating the stability of the high-power laser beam welding (LBW) process and determining the resultant weld quality. However, obtaining these data through experimental or numerical methods remains challenging due to the difficulties in experimental measurements and the high computational demands of numerical modelling. This paper presents a physics-informed generative approach for predicting weld pool and keyhole geometries in the LBW process. With the help of a well experimentally validated numerical model considering the underlying physics in the LBW, the geometries of the weld pool and keyhole under various welding conditions are calculated, serving as the dataset of the generative model. A conditional variational autoencoder model is employed to generate realistic 2D weld pool and keyhole geometries from the welding parameters. We utilize a β-variational autoencoder model with the evidence lower bound loss function and include Kullback–Leibler divergence annealing to better optimize model performance and stability during training. The generated results show a good agreement with the ground truth from the numerical simulation. The proposed approach exhibits the potential of physics-informed generative models for a rapid and accurate prediction of the weld pool geometries across a diverse range of process parameters, offering a computationally efficient alternative to full numerical simulations for process optimization and control in laser beam welding processes.
KW - Laser beam welding
KW - Generative artificial intelligence
KW - Machine learning
KW - Numerical simulation
KW - Weld pool
KW - Keyhole dynamics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656621
DO - https://doi.org/10.2351/7.0001862
SN - 1042-346X
VL - 38
IS - 1
SP - 1
EP - 8
PB - Laser Institute of America
AN - OPUS4-65662
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Kaplan, Alexander
A1 - Rethmeier, Michael
T1 - Digitalisation and Carbon Footprint Evaluation of Gas Metal Arc Welding and Wire-Arc Directed Energy Deposition
N2 - This paper showcases how a holistic approach to digitalisation enables data-driven welding applications, exemplarily for a gas metal arc welding (GMAW) laboratory. The workflow integrates advanced process monitoring, synchronised multi-sensor data acquisition and tools for data analytics. A welding domain-specific data exchange format weldx is presented that unifies and aggregates the data sets acquired during process monitoring with final component quality metrics, supporting reuse, traceability, and reproducibility. Two case studies illustrate the approach. First, GMAW parameters are adaptively adjusted according to local seam geometry to compensate joint-preparation deviations from nominal values typical for large-scale steel fabrication. Second, the seamless data aggregation along the welding production chain enables an automatic life-cycle assessment (LCA), quantifying the environmental impacts of additive manufacturing with DED Arc/M and attributing the dominant contributors to the carbon footprint. Collectively, the results indicate that a fully integrated experimental set-up together with standardised data structures and scalable analytics can couple monitoring, control, and sustainability, thereby realising the potential of digitalisation for high-quality and environmentally informed welding production.
KW - Digitalisation
KW - Arc welding
KW - DED-arc
KW - Life Cycle Assessment
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656812
DO - https://doi.org/10.1088/1757-899X/1342/1/012067
SN - 1757-8981
VL - 1342
IS - 1
SP - 1
EP - 15
PB - IOP Publishing
AN - OPUS4-65681
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Experimental and numerical study on grain refinement in electromagnetic assisted laser beam welding of 5754 Al alloy
N2 - Through experimental observation and auxiliary numerical simulation, this investigation studies the different types of grain refinement of 5754 aluminum alloy laser beam welding by applying a transverse oscillating magnetic field. Scanning electron microscope results have proved that the application of a magnetic field can reduce the average crystal branch width and increase its number. The interaction between the induced eddy current generated by the Seebeck effect and the applied external magnetic field produces a Lorentz force, which is important for the increase in the number of crystal branches. Based on the theory of dendrite fragmentation and the magnetic field-induced branches increment, the grain size reduction caused by the magnetic field is studied. Furthermore, the effects of the magnetic field are analyzed by combining a phase field method model and simulations of nucleation and grain growth. The grain distribution and average grain
size after welding verify the reliability of the model. In addition, the introduction of a magnetic field can increase the number of periodic three-dimensional solidification patterns. In the intersection of two periods of solidification patterns, the metal can be re-melted and then re-solidified, which prevents the grains, that have been solidified and formed previously, from further growth and generates some small cellular grains in the new fusion line. The magnetic field increases the building frequency of these solidification structures and thus promotes this kind of grain refinement.
KW - Laser beam welding
KW - Magnetic field
KW - Crystal branch development
KW - Grain refinement
KW - Periodic solidification pattern
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584905
DO - https://doi.org/10.2351/7.0001085
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
PB - AIP Publishing
AN - OPUS4-58490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Straße, Anne
A1 - Üstündag, Ömer
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
ED - Schmidt, M.
ED - Vollertsen, F.
ED - Govekar, E.
T1 - LMD coatings as filler material for laser beam welded 30 mm thick plates
N2 - The development of high energy laser sources enables single-pass welds of thick plates up to 30 mm, but often additional materials are needed to influence the properties of the weld seams. However, the homogenous distribution of filler materials in form of e.g. electrodes is only possible up to 7 mm while the elements are only traceable up to a depth of 14 mm. To overcome this problem a two-step process is used where first the edges of the weld partners are coated with the filler material by laser metal deposition (LMD) and afterwards are welded by laser beam. Single-pass welds with electromagnetic weld pool support of 30 mm thick S355 J2+N-plates with austenitic AISI 316L-coatings were investigated as well as the influence of the coatings to the penetration depth of the laser beam without electromagnetic weld pool support in double-sided joints. The weld seams were tested by X-ray inspection and cross sections.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
CY - Online meeting
DA - 07.09.2020
KW - Penetration depth
KW - Laser metal deposition (LMD)
KW - Laser beam welding
KW - Filler material distribution
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512790
DO - https://doi.org/10.1016/j.procir.2020.09.055
SN - 2212-8271
VL - 94
SP - 293
EP - 297
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-51279
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
ED - Schmidt, M.
ED - Vollertsen, F.
ED - Schmidt, B. M.
T1 - Preliminary study to investigate the applicability of optical strain measurement technique for the detection of hot cracks in laser metal deposited layers
N2 - Laser metal deposition (LMD) as an additive manufacturing technique became increasingly important in recent years and thus the demand for component safety. This is the reason, for the need for reliable in-situ defect detection techniques. For laser beam weld seams an optical measurement technique based on an optical flow algorithm was successfully used to define the critical straining conditions that lead to hot cracking. This algorithm was adapted for bead-on-plate weld seams on LMD deposited layers of IN718 alloy while performing external strain on the specimen in an externally loaded hot cacking test facility. The resulting transversal hot cracks along the weld seam were localized via X-Ray inspection and the type of cracking confirmed by Scanning Electron Microscopy (SEM). The strain distribution was measured in the vicinity of the solidification front and correlated to the detected hot cracks. Based on the results this technique could be adopted for LMD experiments.
T2 - 12th CIRP Conference on Photonic Technologies [LANE 2022]
CY - Fürth, Germany
DA - 04.09.2022
KW - Laser Metal Deposition (LMD)
KW - Strain measurement
KW - Optical flow
KW - Critical strain
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556445
DO - https://doi.org/10.1016/j.procir.2022.08.034
VL - 111
SP - 335
EP - 339
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-55644
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Avilov, Vjaceslav
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Experimental and numerical investigation of an electromagnetic weld pool control for laser beam welding
N2 - The objective of this study was to investigate the influence of externally applied magnetic fields on the weld quality in laser beam welding. The optimization of the process parameters was performed using the results of computer simulations. Welding tests were performed with up to 20 kW laser beam power. It was shown that the AC magnet with 3 kW power supply allows for a prevention of the gravity drop-out for full penetration welding of 20 mm thick stainless steel plates. For partial penetration welding it was shown that an0.5 T DC magnetic field is enough for a suppression of convective flows in the weld pool. Partial penetration welding tests with 4 kW beam power showed that the application of AC magnetic fields can reduce weld porosity by a factor of 10 compared to the reference joints. The weld surface roughness was improved by 50%.
KW - Laser beam welding
KW - Electromagnetic weld pool support
KW - Hartmann effect
KW - Electromagnetic rectification
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314405
DO - https://doi.org/10.1016/j.phpro.2014.08.006
SN - 1875-3892
VL - 56
SP - 515
EP - 524
PB - Elsevier B.V.
CY - Amsterdam [u.a.]
AN - OPUS4-31440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hickel, Tilmann
A1 - Waske, Anja
A1 - Tehranchi, Ali
A1 - Bhattacharya, Biswajit
A1 - Stawski, Tomasz M.
A1 - Fellinger, Tim-Patrick
A1 - Mehmood, Asad
A1 - Witt, Julia
A1 - Ozcan, Ozlem
A1 - Guilherme Buzanich, Ana
A1 - Kumar, Sourabh
A1 - Mishra, Rajesh Kumar
A1 - Holzer, Marco
A1 - Stucchi de Camargo, Andrea Simone
A1 - Agudo Jácome, Leonardo
A1 - Manzoni, Anna
A1 - Fantin, Andrea
A1 - John, Elisabeth
A1 - Hodoroaba, Vasile-Dan
A1 - Bührig, Sophia
A1 - Murugan, Jegatheesan
A1 - Marschall, Niklas
A1 - George, Janine
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
A1 - Emmerling, Franziska
T1 - Chemically complex materials enable sustainable high-performance materials
N2 - Chemically complex materials (CCMats) including high-entropy alloys, oxides, and related multi-principal element systems offer a paradigm shift in materials design by leveraging chemical diversity to simultaneously optimize functional, structural, and sustainability criteria. The vastness of the compositional and structural space in CCMats propels the field into an expanding exploratory state. To reconcile functional and structural performance across this immense parameter space remains an open challenge. This Perspective evaluates the opportunities and challenges associated with harnessing chemical complexity across a broad spectrum of applications, such as hydrogen storage, ionic conductors, catalysis, magnetics, dielectrics, semiconductors, optical materials, and multifunctional structural systems. It is delineated how three central design strategies: targeted substitution (SUB), defect engineering (DEF), and diversity management (DIV) enable the reconciliation of high functional performance with long-term structural stability and environmental responsibility.
Advances in computational thermodynamics, microstructure simulations, machine learning, and multimodal characterization are accelerating the exploration and optimization of CCMats, while robust data infrastructures and automated synthesis workflows are emerging as essential tools for navigating their complex compositional space. By fostering cross-disciplinary knowledge transfer and embracing data-driven design, CCMats are poised to deliver next-generation materials solutions that address urgent technological, energy, and
environmental demands.
KW - Chemically complex materials
KW - Structural stability
KW - Functional performance
KW - Design strategies
KW - Sustainability
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655598
UR - https://www.sciencedirect.com/science/article/pii/S1359028626000033?via%3Dihub
DO - https://doi.org/10.1016/j.cossms.2026.101256
SN - 1359-0286
VL - 42
SP - 1
EP - 26
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-65559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bustamante, Joana
A1 - Ghata, Anupama
A1 - Naik, Aakash A.
A1 - Ertural, Christina
A1 - Ueltzen, Katharina
A1 - Zeier, Wolfgang G.
A1 - George, Janine
T1 - Thermal transport in Ag8T S6(T = Si, Ge, Sn) argyrodites: an integrated experimental, quantum-chemical, and computational modelling study
N2 - Argyrodite-type Ag-based sulfides combine exceptionally low lattice thermal and high ionic conductivity, making them promising candidates for thermoelectric and solid-state energy applications. In this work, we studied Ag8TS6 (T = Si, Ge, Sn) argyrodite family by combining chemical-bonding analysis, lattice vibrational properties simulation, and experimental measurements to investigate their structural and thermal transport properties. Furthermore, we propose a two-channel lattice-dynamics model based on Grüneisen-derived phonon lifetimes and compare it to an approach using machine-learned interatomic potentials. Both approaches are able to predict thermal conductivity in agreement with experimental lattice thermal conductivities along the whole temperature range, highlighting their potential suitability for future high-throughput predictions. Our findings also reveal a relationship between bond heterogeneity arising from weakly bonded Ag+ ions and occupied antibonding states in Ag–S and Ag–Ag interactions and strong anharmonicity, including large Grüneisen parameters, and low sound velocities, which are responsible for the low lattice thermal conductivity of Ag8SnS6, Ag8GeS6, and Ag8SiS6. We furthermore show that thermal and ionic conductivities in all three compounds are independent of each other and can likely be tuned individually.
KW - Thermal Conductivity
KW - Ionic Conductivity
KW - Machine Learning
KW - Materials Design
KW - Microstructure
KW - Bonding Analysis
KW - Anharmonicity
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657076
DO - https://doi.org/10.1039/D5TA08709K
SN - 2050-7488
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yuanbin
A1 - Zhou, Yuxing
A1 - Ademuwagun, Richard
A1 - Walterbos, Luc
A1 - George, Janine
A1 - Elliott, Stephen R.
A1 - Deringer, Volker L.
T1 - Medium-Range Structural Order in Amorphous Arsenic
N2 - Medium-range order (MRO) is a key structural feature of amorphous materials, but its origin and nature remain elusive. Here, we reveal the MRO in amorphous arsenic (a-As) using advanced atomistic simulations, based on machine-learned potentials derived using automated workflows. Our simulations accurately reproduce the experimental structure factor of a-As, especially the first sharp diffraction peak (FSDP), which is a signature of MRO. We compare and contrast the structure of a-As with that of its lighter homologue, red amorphous phosphorus (a-P): we find that a-As has a more uniform dihedral-angle distribution, and so we confirm that its structure can be thought of as a 3-fold coordinated continuous random network in first approximation, in contrast to the more molecular-cluster-like structure of a-P. The pressure-dependent structural behaviors of a-As and a-P differ as well, and the origin of the FSDP is closely correlated with the size and spatial distribution of voids in the amorphous networks. Our work provides fundamental insights into MRO in an amorphous elemental system, and more widely it illustrates the usefulness of automation for machine-learning-driven atomistic simulations.
KW - Machine Learned Interatomic Potentials
KW - Amorphous
KW - Advanced Materials
KW - Automation
KW - Digitalisation
KW - Structure-Property- Relationships
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655952
DO - https://doi.org/10.1021/jacs.5c18688
SN - 0002-7863
SP - 1
EP - 13
PB - American Chemical Society (ACS)
AN - OPUS4-65595
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Marquardt, Raphael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Influence of laser power on the melt pool shape of handheld laser beam welding of 1.5 mm thick micro alloyed steel
N2 - Manual welding of structures requires highly skilled welders due to the large heat-affected zone of arc-based processes, that can negatively impact microstructure and cause distortion. Handheld laser beam welding is a promising alternative with high welding velocity and a concentrated heat input. However, its current use in industry is limited to parts with aesthetic requirements, often made of high-alloyed steel. To extend the use of handheld laser beam welding to low-cost steels with good mechanical properties, this study investigates the influence of laser power on the melt pool shape for micro-alloyed steel with a thickness of 1.5 mm. Tested joint geometries are T-joints welded with filler wire as well as butt joints and overlap joints without filler wire, which are typically found in assemblies under mechanical load. Weld quality is assessed by weld porosity analysis. The results show that the handheld laser beam welding with filler wire produces T-joints with a very good external appearance, but with porosity between level C and D in the cross sections according to DIN EN ISO 13919-1. By increasing the laser power, a deep penetration of the T-joint zone can be achieved without increasing the actual throat thickness. For handheld laser beam welding of butt joints a full penetration weld of the highest quality class can be reached. Overlap joints can be welded with full or partial penetration depending on the laser power selected, with quality classes between B and C in terms of porosity.
T2 - 20th Nordic Laser Materials Processing Conference
CY - Kongens Lyngby, Denmark
DA - 26.08.2025
KW - Hand held laser welding
KW - Laser beam welding
KW - Low alloyed steel
KW - Process parameter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641671
DO - https://doi.org/10.1088/1757-899X/1332/1/012015
SN - 1757-899X
VL - 1332
SP - 1
EP - 6
PB - Institute of Physics
CY - London [u.a.]
AN - OPUS4-64167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
A1 - Ouellet-Plamondon, Claudiane
A1 - Reyes, Kristofer
T1 - Introduction to the “Accelerate Conference 2023–2024” themed collection
N2 - The collection showcases the ways in which automation, machine learning and robotics are transforming experimental materials science and chemistry into continuous, computationally integrated processes. It features innovations regarding autonomous laboratories, Bayesian optimisation, high-throughput experimentation and computation, and AI-driven literature extraction, which simplify and scale up materials discovery. Together, these works outline a modular, responsible framework for accelerating scientific progress through human-guided, data-driven autonomy.
KW - Automation
KW - Materials Acceleration Platforms
KW - Synthesizability
KW - Workflows
KW - Large Language Models
KW - Ontologies
KW - Materials Discovery
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654658
DO - https://doi.org/10.1039/d5dd90057c
SN - 2635-098X
SP - 1
EP - 2
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wiesner, Yosri
A1 - Bednarz, Marius
A1 - Braun, Ulrike
A1 - Bannick, Claus Gerhard
A1 - Ricking, Mathias
A1 - Altmann, Korinna
T1 - A promising approach to monitor microplastic masses in composts
N2 - Inputs of plastic impurities into the environment via the application of fertilizers are regulated in Germany and the EU by means of ordinances. Robust and fast analytical methods are the basis of legal regulations. Currently, only macro- and large microplastic contents (>1 mm) are measured. Microplastics (1–1,000 µm), are not yet monitored. Thermal analytical methods are suitable for this purpose, which can determine the mass content and can also be operated fully automatically in routine mode. Thermal extraction desorption-gas chromatography/mass spectrometry (TED-GC/MS) allows the identification of polymers and the determination of mass contents in solid samples from natural environments. In accordance with the German or European Commission (EC) Fertiliser Ordinance, composting plants should be monitored for microplastic particles with this method in the future. In this context a compost plant was sampled. At the end of the rotting process, the compost was sieved and separated in a coarse (>1 mm) and a fine fraction (<1 mm). The fine fraction was processed using density separation comparing NaCl and NaI as possible salt alternative and screened for microplastic masses by TED-GC/MS with additional validation and quality assurance experiments. With TED-GC/MS total microplastics mass contents of 1.1–3.0 μg/mg in finished compost could be detected with polyethylene mainly. What differs much to the total mass of plastics in the coarse fraction with up to 60 μg/mg, which were visually searched, identified via ATR-FTIR and gravimetrically weighted.
KW - Microplastics
KW - TED-GC/MS
KW - Compost
KW - Monitoring
KW - Soil
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586688
DO - https://doi.org/10.3389/fenvc.2023.1281558
SN - 2673-4486
VL - 4
SP - 1
EP - 12
PB - Frontiers Media
CY - Lausanne
AN - OPUS4-58668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Linberg, Kevin
A1 - Röder, Bettina
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Michalchuk, Adam
T1 - Controlling polymorphism in molecular cocrystals by variable temperature ball milling
N2 - Mechanochemistry offers a unique opportunity to modify and manipulate crystal forms, often providing new products as compared with conventional solution methods. While promising, there is little known about how to control the solid form through mechanochemical means, demanding dedicated investigations. Using a model organic cocrystal system (isonicotinamide:glutaric acid), we here demonstrate that with mechanochemistry, polymorphism can be induced in molecular solids under conditions seemingly different to their conventional thermodynamic (thermal) transition point. Whereas Form II converts to Form I upon heating to 363 K, the same transition can be initiated under ball milling conditions at markedly lower temperatures (348 K). Our results indicate that mechanochemical techniques can help to reduce the energy barriers to solid form transitions, offering new insights into controlling polymorphic forms. Moreover, our results suggest that the nature of mechanochemical transformations could make it difficult to interpret mechanochemical solid form landscapes using conventional equilibrium-based tools.
KW - Mechanochemistry
KW - Polymorphism
KW - TRIS
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564728
DO - https://doi.org/10.1039/d2fd00115b
SP - 1
EP - 16
PB - Royal Society of Chemistry
AN - OPUS4-56472
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmann, Daniel
A1 - Saal, Leon
A1 - Zietschmann, F.
A1 - Mai, M.
A1 - Altmann, Korinna
A1 - Al-Sabbagh, Dominik
A1 - Schuhmann, P.
A1 - Ruhl, A.
A1 - Jekel, M.
A1 - Braun, Ulrike
T1 - Characterization of activated carbons for water treatment using TGA‑FTIR for analysis of oxygen‑containing functional groups
N2 - Water treatment with activated carbon (AC) is an established method for the removal of organic micropollutants and natu ral organic matter. However, it is not yet possible to predict the removal of individual pollutants. An appropriate material characterization, matching adsorption processes in water, might be the missing piece in the puzzle. To this end, this study examined 25 diferent commercially available ACs to evaluate their material properties. Frequently reported analyses, including N2 adsorption/desorption, CHNS(O), point of zero charge (PZC) analysis, and X-ray photoelectron spectroscopy, were conducted on a selected subset of powdered ACs. Inorganic elements examined using X-ray fuorescence and X-ray difraction spectroscopy revealed that relative elemental contents were distinctive to the individual AC’s raw material and activation procedure. This study also is the frst to use thermogravimetric analysis (TGA) coupled to Fourier-transform infrared spectroscopy (FTIR) to conduct quantitative analyses of functional surface oxygen groups (SOGs: carboxylic acid, anhydride, lactone, phenol, carbonyl, and pyrone groups) on such a large number of ACs. The comparably economical TGA method was found to provide good surrogates for the PZC by pyrolytic mass loss up to 600 ◦C (ML600), for the oxygen content by ML1000 and for the carbon content by oxidation. Mass loss profles depict the AC’s chemistry like fngerprints. Furthermore, we found that SOG contents determined by TGA-FTIR covered a wide individual range and depended on the raw material and production process of the AC. TGA and TGA-FTIR might therefore be used to identify the suitability of a particular AC for a variety of target substances in diferent target waters. This can help practitioners to control AC use in waterworks or wastewater treatment plants.
KW - Adsorbtion
KW - Organic contaminants
KW - Temperature-programmed desorption
KW - Proximate analysis
KW - Principal component analysis
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555506
DO - https://doi.org/10.1007/s13201-022-01723-2
SN - 2190-5495
VL - 12
SP - 1
EP - 13
PB - Springer
CY - Berlin
AN - OPUS4-55550
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pérez-Padilla, Víctor
A1 - Burnage, Samual C.
A1 - Wittwer, Philipp
A1 - Valderrey, Virginia
A1 - Bell, Jérémy
A1 - Gawlitza, Kornelia
A1 - Rurack, Knut
T1 - Detection of Perfluoroalkylic Acids From Water Using a Guanidine-Based Fluorescent Probe and Microfluidic Droplet Extraction
N2 - Perfluoroalkylic acids (PFAAs), a subclass of per- and polyfluoroalkyl substances (PFAS), are stable, widely used industrial compounds posing environmental concerns due to their persistence and toxicity. Regulatory actions and remediation strategies necessitate effective onsite analytical methods for PFAS management. We developed an optical sensing system using a fluorescent probe with a benzoxadiazole core and guanidine receptor in a droplet-based microfluidic assay to detect PFAAs in water samples with low detection limits. The PFAAs binding enhances the probe's fluorescence in organic media through protonation-mediated hydrogen bond-assisted ion pairing, exploiting two complementary supramolecular forces. Direct detection employs a liquid-liquid extraction protocol in the microfluidic device, achieving detection limits for PFOA and PFOS down to ≥0.5 µm, with a dynamic range up to 200 µm for sample volumes <100 µL. HCl/KCl buffering facilitates analyte desalting and phase transfer for quantitation from surface water. Additionally, we developed a method involving a thin polymer layer of the probe and a crosslinker on submicron silica particles for direct detection of PFAAs in water. Our approaches provide sensitive, direct recognition and indication of PFAAs, advancing the field beyond indirect sensing and offering improved background suppression, rapid assay times, and a modular design for targeting other PFAS subclasses.
KW - PFAS
KW - Fluorescence
KW - Microfluidics
KW - Droplet extraction
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657330
DO - https://doi.org/10.1002/adsr.70145
SN - 2751-1219
VL - 5
IS - 3
SP - 1
EP - 13
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65733
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Serrano-Munoz, Itziar
A1 - Dufrenoy, Philippe
A1 - Magnier, Vincent
T1 - Rationalizing the microstructure interplay in the thermal conductivity of a metal matrix composite via 3D imaged-based finite element modeling
N2 - The thermal performance of metallic brake lining materials plays a decisive role in the safety and efficiency of high-speed railway braking systems. In this study, a combined experimental–numerical methodology is developed to rationalize the influence of microstructural constituents on the effective thermal conductivity of a sintered metal matrix composite (MMC) brake lining. Laser Flash Analysis (LFA) is first employed to determine the thermal conductivity of some individual constituents as well as that of reference composites. X-ray CT (XCT) provides three-dimensional reconstructions of the microstructure that are subsequently used to generate realistic image-based finite element meshes. The unknown thermal conductivities of the graphite particles are identified through a Finite Element Model Updating (FEMU) scheme, where numerical predictions of the effective conductivity are iteratively matched to LFA measurements. These findings highlight the strong anisotropy of graphite particles and their favored orientation after compaction, which governs heat transport pathways. Moreover, the presence of intra-, inter-, and inter-connectivity porosity within and around the graphite is shown to significantly reduce the transverse conductivity, rationalizing the discrepancy between the FEM predictions and experimental values. Overall, the proposed approach demonstrates how combining LFA, XCT and FEMU enables the identification of constituent-level conductivities and provides new insights into the microstructure/thermal-property relationships of MMC brake linings.
KW - Brake lining material
KW - Thermal conductivity
KW - Graphite particles
KW - Laser flash analysis (LFA)
KW - X-ray computed tomography (XCT)
KW - 3D finite element model updating (FEMU)
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657756
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2026.128735
SN - 0017-9310
VL - 264
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Getenet, M.
A1 - Garcia-Ruiz, J. M.
A1 - Otálora, F.
A1 - Emmerling, Franziska
A1 - Al-Sabbagh, Dominik
A1 - Verdugo-Escamilla, E.
T1 - A comprehensive methodology for monitoring evaporitic mineral precipitation and hydrochemical evolution of saline lakes: The case of Lake Magadi soda brine (East African Rift Valley, Kenya)
N2 - Lake Magadi, East African Rift Valley, is a hyperalkaline and saline soda lake highly enriched in Na+, K+, CO32–, Cl–, HCO3–, and SiO2 and depleted in Ca2+ and Mg2+, where thick evaporite deposits and siliceous sediments have been forming for 100 000 years. The hydrogeochemistry and the evaporite deposits of soda lakes are subjects of growing interest in paleoclimatology, astrobiology, and planetary sciences. In Lake Magadi, different hydrates of sodium carbonate/bicarbonate and other saline minerals precipitate. The precipitation sequence of these minerals is a key for understanding the hydrochemical evolution, the paleoenvironmental conditions of ancient evaporite deposits, and industrial crystallization. However, accurate determination of the precipitation sequence of these minerals was challenging due to the dependency of the different hydrates on temperature, water activity, pH and pCO2, which could induce phase transformation and secondary mineral precipitation during sample handling. Here, we report a comprehensive methodology applied for monitoring the evaporitic mineral precipitation and hydrochemical evolution of Lake Magadi. Evaporation and mineral precipitations were monitored by using in situ video microscopy and synchrotron X-ray diffraction of acoustically levitated droplets. The mineral patterns were characterized by ex situ Raman spectroscopy, X-ray diffraction, and scanning electron microscopy. Experiments were coupled with thermodynamic models to understand the evaporation and precipitation-driven hydrochemical evolution of brines. Our results closely reproduced the mineral assemblages, patterns, and textural relations observed in the natural setting. Alkaline earth carbonates and fluorite were predicted to precipitate first followed by siliceous sediments. Among the salts, dendritic and acicular trona precipitate first via fractional crystallization─reminiscent of grasslike trona layers of Lake Magadi. Halite/villiaumite, thermonatrite, and sylvite precipitate sequentially after trona from residual brines depleted in HCO3–. The precipitation of these minerals between trona crystals resembles the precipitation process observed in the interstitial brines of the trona layers. Thermonatrite precipitation began after trona equilibrated with the residual brines due to the absence of excess CO2 input. We have shown that evaporation and mineral precipitation are the major drivers for the formation of hyperalkaline, saline, and SiO2-rich brines. The discrepancy between predicted and actual sulfate and phosphate ion concentrations implies the biological cycling of these ions. The combination of different in situ and ex situ methods and modeling is key to understanding the mineral phases, precipitation sequences, and textural relations of modern and ancient evaporite deposits. The synergy of these methods could be applicable in industrial crystallization and natural brines to reconstruct the hydrogeochemical and hydroclimatic conditions of soda lakes, evaporite settings, and potentially soda oceans of early Earth and extraterrestrial planets.
KW - Crystallization
KW - Precipitation
KW - Crystals
KW - Evaporation
KW - Minerals
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546712
DO - https://doi.org/10.1021/acs.cgd.1c01391
SN - 1528-7483
VL - 22
IS - 4
SP - 2307
EP - 2317
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-54671
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wagner, Jan
A1 - Häfner, P.
A1 - Reimann, H.-A.
A1 - Schartel, Bernhard
T1 - Valorization of Natural Fibers in Flame Retarded Poly(lactic acid)
N2 - Extensive research has explored natural fiber reinforced composites, typically focusing on a single fiber within a polymer matrix. Comprehensive comparisons across different natural fibers in the same polymer, which are critical for industrial material selection, remain limited. This work presents a systematic comparison of untreated hemp, flax, and sisal fibers incorporated at varying fiber lengths and loadings into flame retarded poly(lactic acid) (PLA). Fire behavior, thermal, and mechanical responses were investigated through thermogravimetry, UL 94, and cone calorimetry, alongside crystallinity, molecular weight (MW), and microstructural analysis. Fiber incorporation reduced the peak heat release rate (pHRR) by up to 30 % in 30 wt% hemp, attributed to protective layer formation, but increased flammability in UL 94. A phytic acid melamine salt combined with expandable graphite and 20 wt% hemp produced incomplete combustion at 50 kW/m², raising char residue from 4 to 24 wt% and halving pHRR. Petrella plots revealed that fiber addition alone lowered fire load and flashover propensity as effectively as phytic acid melamine; with hemp, phytic acid and expendable graphite, the flashover hazard and fire load were halved. MW was preserved while crystallinity and modulus increased with fiber content. Hemp delivered the most consistent reinforcement, while optimized processing enabled flax and sisal to improve stiffness. Performance gains were strongest when individual fibers were dispersed via optimized processing, preventing bundle fracture under load. Plasma modification of the fibers improved the maximum tensile strength in the composites. A practical guide is provided for valorizing natural fibers in PLA composites, demonstrating routes to bio-based, compostable materials with improved fire safety and mechanical performance suitable for industrial processing.
KW - Poly(lactic acid)
KW - Hemp
KW - Sisal
KW - Flax
KW - Flame retardant
KW - Phytic acid
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653038
DO - https://doi.org/10.1016/j.mtcomm.2025.114575
SN - 2352-4928
VL - 50
SP - 1
EP - 41
PB - Elsevier Ltd.
AN - OPUS4-65303
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sanchez-Olivares, Guadalupe
A1 - Brehme, Sven
A1 - Calderas, F.
A1 - Schartel, Bernhard
T1 - Flame Retardant Polyolefins Using Fibers From Leather Waste: Adjusting Extrusion Variables to Balance the Property Profile
N2 - The extrusion processing variables represent a key to the optimal use of additives and thus the development of flame-retardant polymer composites. Adjusting the property profile, for example, finding a balance between flame retardancy and mechanical properties is the main challenge. In this work, the effect of blending temperature and rotational speed on physico-mechanical properties and fire behavior of polyolefin composites was investigated. High-density polyethylene or polypropylene was used as polymer matrices; the polymers were compounded by the extrusion process using industrial-waste leather fibers as flame retardant adjuvant and commercial flame-retardant additives. A detailed rheological analysis highlighted different viscoelastic behavior, that is, a predominant elastic or viscous one. The effect of the extrusion processing variables was also investigated on the morphology, mechanical properties, thermal decomposition, fire behavior under forced flaming combustion and flammability. Important improvements were revealed with respect to using only high loading of flame retardants. For high-density polyethylene-based composites, impact resistance and elongation at break increased 8 and 7.5 times, respectively. The total heat evolved (87MJ/m2), effective heat of combustion (31.6MJ/kg), flame retardancy (UL 94 rating) results were comparable with the reference sample. Meanwhile for polypropylene composites, the impact resistance increased 2.2 times and the flame retardancy was improved from no rating in the UL 94 vertical test to V-0 rating. Tailored processing was highlighted as an autonomous and powerful approach to achieve balanced and demanding properties.
KW - Biomaterials
KW - Composites
KW - Extrusion
KW - Flame retardance
KW - Leather waste
KW - Polyolefins
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656732
DO - https://doi.org/10.1002/vnl.70048
SN - 1548-0585
SN - 1083-5601
VL - 32
IS - 2
SP - 410
EP - 430
PB - Wiley Periodicals LLC.
AN - OPUS4-65673
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos, José Antonio
A1 - Bienert, M.
A1 - Gugin, Nikita
A1 - Emmerling, Franziska
A1 - Maiwald, Michael
T1 - A database to select affordable MOFs for volumetric hydrogen cryoadsorption considering the cost of their linkers
N2 - Physical adsorption at cryogenic temperature (cryoadsorption) is a reversible mechanism that can reduce the pressure of conventional compressed gas storage systems. Metal–organic framework (MOF) materials are remarkable candidates due to the combination of high specific surface area and density which, in some cases, provide a high volumetric storage capacity. However, such extensive use of MOFs for this application requires the selection of affordable structures, easy to produce and made from feasible metallic and organic components. Herein, we introduce a MOF database detailing the crystallographic and porous properties of 3600 existing MOFs made from industrially relevant metals and their organic composition. The comparison of the available minimum costs of linkers allowed the creation of a database to select affordable structures with high potential for volumetric hydrogen storage by cryoadsorption, considering their composition based on individual or mixed building blocks. A user inter� face, available online, facilitates the selection of MOFs based on the properties or names of structures and linkers.
KW - MOF´s
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583619
DO - https://doi.org/10.1039/d3ma00315a
VL - 4
IS - 18
SP - 4226
EP - 4237
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58361
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Suárez Ocaño, Patricia
A1 - Ávila Calderón, Luis
A1 - Agudo Jácome, Leonardo
A1 - Rehmer, Birgit
A1 - Mohr, Gunther
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Effect of 700–900 °C heat treatments and room and high temperature tensile deformation on the microstructure of laser powder bed fused 316L stainless steel
N2 - The effect of post-processing heat treatments on the hierarchical microstructure evolution and mechanical strength of the austenitic stainless steel 316L produced by laser powder bed fusion has been investigated. Heat treatments between 700 and 900 ◦C and 0.5 to 3 h, were applied to samples treated at 450 ◦C for 4 h. The results showed a stable microstructure at all studied temperatures and times in terms of grain size, morphology, aspect ratio, density of low-angle grain boundaries, and texture. However, temperature and time promoted the diffusion of segregated elements together with a reduction in dislocation density and disappearance of the cellular structure. This was associated with a reduction in hardness and tensile proof strength at both room and high temperature. In addition, microstructural characterization coupled with thermodynamic CALPHAD-based equilibrium calculations showed that the formation of carbides and intermetallic phases was already visible after annealing at 800 ◦C for 3 hours, although these intermetallics did not affect the tensile properties at this level. Analysis of the microstructure evolution after tensile deformation showed differences in the deformation mechanisms at room and high temperature, with twinning and martensitic transformation occurring at room temperature, the latter not widely reported for additively manufactured 316L. Finally, comparisons with similar materials produced under comparable conditions showed differences in the tensile properties, attributed to differences in chemical composition and the associated presence of stacking faults in the undeformed state.
KW - Additive manufacturing
KW - 316L stainless steel
KW - Heat treatments
KW - Tensile properties
KW - Microstructure
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632471
DO - https://doi.org/10.1016/j.msea.2025.148469
SN - 0921-5093
VL - 939
SP - 1
EP - 24
PB - Elsevier
CY - Amsterdam
AN - OPUS4-63247
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jentzsch, Stefan
A1 - Stock, Daniel
A1 - Häcker, Ralf
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
A1 - Klingbeil, Dietmar
A1 - Kindrachuk, Vitaliy
T1 - Shear Band Formation with Split Hopkinson Bar Experiments
N2 - The essence of dynamic failure is closely linked to dramatic shear deformations which often lead to the formation of adiabatic shear bands (ASB). Under high loading velocities and the subsequent rapid temperature increase, the localization of shear strain is crucial in view of safety issues of systems in mechanical and aircraft engineering, especially with respect to fast rotating components and diverse crash scenarios. In this research, we perform high speed impact tests at the split Hopkinson pressure bar (SHPB) setup and use particular hat-shaped specimen geometries that resemble the stresses and failure conditions at the component level.
In the first step, we specify a notched specimen geometry using finite element (FE) simulations to ensure pure shear. Further, quasi-static compressive tests and a series of impact tests at high strain rates of 10^3-10^4 s^-1 are conducted on specimens manufactured from a fine-grain structural steel with the properties of S355. Optical microscopy and electron backscatter diffraction (EBSD) of the sheared zones unveil significant localization to maximal shear strains of about 0.9 accompanied by grain refinement by factors 5 to 14. The displacements across the surface of the specimens are captured with subset-based local digital image correlation (DIC) during the impact time, and serve as an objective to validate a viscoplastic constitutive relationship. More precisely, the deformation distribution is accurately reproduced by the widely recognized Johnson-Cook (JC) model, which features an enhanced description of damage evolution. Thus, combining experimental and characterization techniques, continuum mechanics and reasonable optimization strategies for the identification of model parameters provides an efficient approach for comprehensive insights into the strain localization behaviour and its impact on the mechanical performance of S355 under extreme strain rates and deformations.
KW - Adiabatic shear bands
KW - Finite element analysis
KW - Viscoplastic material modelling
KW - Split Hopkinson pressure bar
KW - Hat-shaped specimen
KW - Johnson–Cook parameter identification
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613339
DO - https://doi.org/10.1016/j.ijmecsci.2024.109749
VL - 284
SP - 1
EP - 14
PB - Elsevier BV
AN - OPUS4-61333
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Abel, Andreas
A1 - Rosalie, Julian
A1 - Reinsch, Stefan
A1 - Zapala, Pawel
A1 - Michels, Heiner
A1 - Skrotzki, Birgit
T1 - Influence of Mo and B additions in intermetallic near-Fe3Al alloys on microstructure and mechanical properties
N2 - Iron aluminides, already reported in the late 19th century, did not cease to attract the interest of scientists and engineers ever since. Besides good oxidation resistance, low density and resource availability, potentials for hightemperature strengths that compete with high-alloy steels were unlocked by low alloy contents. Still, research on alloy design continues, as alloying usually comes at the price of brittleness in low-temperature regimes. A potential candidate is the quinary Fe–Al–Mo–Ti–B system which is strengthened by solid solution and eutectic borides. It was shown to have good strength and outstanding creep resistance under compressive loading up to elevated temperatures. Although the individual effect of alloy additions is well understood in iron aluminides, little is known about the combined effects of alloying concentrations on microstructure, phase stability and mechanical properties. Therefore a systematic study of two Ti-doped near-Fe3Al alloys with varying contents of Mo (2–4 at.%) and B (0.5–1 at.%) was conducted. In total eight different alloys were fabricated by investment casting into ceramic shell molds. Alloys were characterized and compared by grain size, phase transitions, microstructure evolution as well as elemental compositions and volume fractions of phases. For mechanical characterization, macrohardness and microhardness tests as well as tensile tests at ambient and high tempera tures were conducted. Independent of alloy additions, alloys with 24–25 at.% Al exhibit superior proof strength due to a higher matrix hardness. Decreasing B content generally decreases strength by lower secondary phase fractions which contribute via particle hardening. Reducing Mo content decreases both the solute concentration in the matrix and secondary phase fractions. Surprisingly, strength is similar or even superior to alloys with higher Mo content. Strength relations are discussed with a focus on solid-solution hardening theory and other competing strengthening mechanisms.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-585284
DO - https://doi.org/10.1016/j.intermet.2023.108074
VL - 163
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-58528
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Häßler, Dustin
A1 - Mund, Maximilian
A1 - Daus, Lars-Hendrik
A1 - Hothan, Sascha
A1 - Schaumann, Peter
A1 - Schartel, Bernhard
T1 - Durability of intumescent coatings and recommendations for test concepts for a working life of more than 10 years
N2 - It is an essential requirement for all building products to ensure durability of their fire safety. Throughout the working life of products, intumescent coatings are aged by certain climatic factors. To predict a lifetime of several years, generally the behaviour of the intumescent coating is extrapolated based on accelerated artificial ageing. The established German and European procedures to assess the durability assume a working life of at least 10 years. For a longer period, additional evidence is required; yet the procedure and the specifications to justify this are not described. In addition to addressing this formal lack, from a scientific point of view it is necessary to investigate the degradation of intumescent coatings in detail and to propose a reliable test concept to assess durability for more than 10 years. This paper summarises the existing knowledge about the ageing of intumescent coatings. The results of various demanding weathering approaches are presented for two intumescent coatings tested in a joint research project. Moreover, formulations with a reduced amount of functionally relevant components were analysed to gain insight into the associated effects. Derived from these research results and knowledge, recommendations are proposed to assess the durability of intumescent coatings for more than 10 years based on a combination of verifications.
KW - Ageing
KW - Fire protection
KW - Intumescent coating
KW - Steel construction
KW - Working life
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603852
DO - https://doi.org/10.1016/j.firesaf.2024.104173
SN - 0379-7112
VL - 146
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-60385
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vecchiato, L.
A1 - Madia, Mauro
A1 - Meneghetti, G.
T1 - Extension of the peak stress method to estimate the fatigue limit of welded joints by means of the cyclic R-curve method
N2 - A new simplified and effective method has been formalised to estimate the Constant Amplitude Fatigue Limit (CAFL) of stress-relieved steel welded joints subjected to uniaxial push–pull loading and failing from the weld toe. Starting from the sharp V-notch assumption of the NSIF approach and the cyclic R-curve of the material in the heat affected zone, the proposed method identifies the CAFL as threshold level of the local stress field at the V-notched weld toe in the uncracked configuration. Such threshold stress field assures the crack arrest at the V-notched weld toe, according to the cyclic R-curve analysis. The method has been validated against experimental results and proved effective for a straightforward assessment of the CAFL of welded joints, as the stable crack propagation analysis of classical fracture mechanics approaches can be avoided.
KW - Cyclic R-curve
KW - Welded joint
KW - Fatigue limit
KW - Peak stress method
KW - Finite element analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581059
DO - https://doi.org/10.1016/j.tafmec.2023.104039
SN - 0167-8442
VL - 127
SP - 1
EP - 19
PB - Elsevier
AN - OPUS4-58105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chang, Yen-Ting
A1 - Sharda, Abhi
A1 - Rosalie, Julian
A1 - Maaß, Robert
A1 - Charpagne, Marie A.
T1 - A bcc refractory high-entropy alloy: the ideal case of smooth plastic flow
N2 - Single crystalline metals exhibit correlated dislocation dynamics, irrespective of lattice system. This collective evolution of dislocation structures is intermittent and scale-free, implying divergent length scales that play a critical role in failure initiation and therefore microstructural design. Here we report on a HfNbTaTiZr refractory high-entropy alloy, that lacks criticality in the collective dislocation response. This unusual behaviour manifests itself in almost quenched-out microplastic stress-strain fluctuations and sluggish dislocation avalanching, otherwise only seen in complex engineering alloys. These findings demonstrate how the high-entropy paradigm can serve as a role model to effectively suppress unwanted plastic fluctuations in metals deformation.
KW - Plasticity
KW - Dislocations
KW - Avalanches
KW - Refractory high-entropy alloys
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630241
DO - https://doi.org/10.1080/21663831.2025.2497860
SN - 2166-3831
SP - 1
EP - 8
PB - Taylor & Francis Group
AN - OPUS4-63024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sanchez-Olivares, G.
A1 - Brehme, Sven
A1 - Zacarias Martinez, S.
A1 - Calderas, F.
A1 - Schartel, Bernhard
T1 - Mix and Match: Industrial-waste Leather Fibers Substitute Flame Retardants and Reinforce Mechanical Properties in Appropriately Processed Thermoplastic Poly(urethane) Composites
N2 - The research and development of firesafe and sustainable polymer materials with appropriate mechanical properties for cable jacketing applications is addressed. Composites based on thermoplastic polyurethane (TPU) combining industrial-waste leather fibers and a commercial flame-retardant additive (ammonium polyphosphate – APP) are investigated. TPU composites were extruded under different temperature profiles and rotational speeds to obtain flame-retardant composites with appropriate mechanical properties. The detailed investigation of viscoelastic properties, morphology, tensile mechanical properties, pyrolysis, forced-flaming combustion and reaction to small flame highlights that applying optimized processing is key to producing TPU composites with the best tensile mechanical properties and flame retardancy. This finding was associated with the production of a highly elastic network, which was attributed to better dispersion and distribution of leather fibers and APP particles. TPU composites, combining 5 phr (parts per hundred resin) industrial-waste leather fibers and 5 phr APP, were compared to composites using 10 phr of APP. The same UL 94 V-0 classification, equal reduced fire risk (MARHE) with diminished smoke release, similar Young’s modulus and elongation at break, and improved tensile strength (20%) are achieved by replacing 50% APP with industrial-waste leather fibers; thus, the industrial-wastes leather fibers are simultaneously upcycled for this specific application.
KW - TPU
KW - Flame retardancy
KW - Viscoelastic properties
KW - Cable jacketing
KW - Natural waste fibers
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658524
DO - https://doi.org/10.1016/j.rineng.2026.110316
SN - 2590-1230
VL - 30
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65852
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tabaka, Weronika
A1 - Schartel, Bernhard
T1 - Less is More: Optimised Fire Performance in Glass Fibre-reinforced Polybutylene Terephthalate Laminates with Concentrated Flame Retardant Top Layer
N2 - To achieve optimum fire performance while maintaining mechanical integrity, flame retardants (FR) were strategically concentrated in the surface layer of a two-layer glass fibre-reinforced polybutylene terephthalate (PBT) laminate structure. Three potentially synergistic FR systems were selected to improve the fire performance of glass fibre-reinforced PBT: boehmite (AlOOH) with melamine polyzinc phosphate (MPZnP), aluminium diethyl phosphinates (AlPi) with melamine cyanurate (MC), and expandable graphite (EG) with melamine polyphosphate (MPP). Limited Oxygen Index (LOI) and UL-94 testing highlighted the influence of laminate architecture on flammability. The cone calorimeter results showed that increasing the FR concentration in the top layer significantly reduced both the peak heat release rate (PHRR) and the maximum average rate of heat emission (MARHE), with improvements depending on the specific FR system used. The laminate L-PBT/GF/AlOOH/MPZnP with a 2:2
thickness ratio showed outstanding performance, achieving a 45 % reduction in MARHE compared to composites with uniform FR distribution. This result showcases the superior thermal barrier properties and synergistic behaviour of AlOOH and MPZnP. The fire performance of laminates containing AlPi and MC was strongly influenced by the distribution and concentration of AlPi/MC. The EG/MPP system was found to be highly effective, forming a protective intumescent layer that significantly reduced both HRR and MARHE, demonstrating the effectiveness of strategically concentrating FR in the top layer.
KW - Glass fibres
KW - PBT
KW - Flame retardants
KW - Composites
KW - Laminates
KW - Fire behaviour
KW - Flammability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626381
DO - https://doi.org/10.1016/j.jcomc.2025.100577
SN - 2666-6820
VL - 16
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62638
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hupp, Vitus
A1 - Schartel, Bernhard
A1 - Flothmeier, K.
A1 - Hartwig, A.
T1 - Fire Behavior of Pressure-sensitive Adhesive Tapes and Bonded Materials
N2 - Pressure-sensitive adhesive tapes are used in several industrial applications such as con-struction, railway vehicles and the automotive sector,where the burning behavior is ofcrucial importance. Flame retarded adhesivetapes are developed and provided, however,often without considering the interaction of adhesive tapes and the bonded materialsduring burning nor the contribution of the tapes to fire protection goal of the bondedcomponents in distinct fire tests. This publication delivers an empirical comprehensiveknowledge how adhesive tapes and their flame retardancy effect the burning behaviorof bonded materials. With a special focus on the interaction between the single compo-nents, one flame retarded tape and one tapewithout flame retardant are examined inscenarios of emerging and developing fires, along with their bonds with the commonmaterials wood, zinc-plated steel, mineral wool, polycarbonate, and polymethylmethacry-late. The flame retardant significantly improved the flame retardancy of the tape as afree-standing object and yielded a V-2 rating in UL 94 vertical test and raised the OxygenIndex by 5 vol.%. In bonds, or rather laminates, the investigations prove that the choiceof carrier and substrates are the factors with the greatest impact on the fire propertiesand can change the peak of heat release rate and the maximum average rate of heatemission up to 25%. This research yielded a good empirical overall understanding of thefire behavior of adhesive tapes and bonded materials. Thus, it serves as a guide for tapemanufacturers and applicants to develop tapes and bonds more substrate specific.
KW - Adhesives
KW - Cone calorimeter
KW - Flame retardancy
KW - Laminates
KW - Phosphorus flame retardants
KW - Pressure-sensitive adhesive
KW - Tapes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593207
DO - https://doi.org/10.1002/fam.3171
SN - 0308-0501
SN - 1099-1018
VL - 48
IS - 1
SP - 114
EP - 127
PB - Wiley
CY - New York, NY
AN - OPUS4-59320
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Avila Calderon, Luis Alexander
A1 - Schriever, Sina
A1 - Hang, Y.
A1 - Olbricht, Jürgen
A1 - Portella, P. D.
A1 - Skrotzki, Birgit
T1 - Creep reference data of single-crystal Ni-based superalloy CMSX-6
N2 - The article presents creep data for the single-crystal, [001]-oriented nickel-based superalloy CMSX-6, tested at a temperature of 980 °C under initial stresses ranging from 140 MPa to 230 MPa. The constant-load creep experiments were performed in accordance with DIN EN ISO 204:2019–4 standard within an ISO 17025 accredited laboratory. A total of 12 datasets are included, each of which includes the percentage creep extension as a function of time. The data series and associated metadata were systematically documented using a data schema specifically developed for creep data of single-crystal Ni-based superalloys. This dataset serves multiple purposes: it can be used to compare with one's own creep test results on similar materials, to verify testing setups (e.g., by replicating tests on the same or comparable materials), to calibrate and validate creep models, and to support alloy development efforts.
KW - NFDI MatWerk
KW - Referenzdaten
KW - Kriechen
KW - CMSX-6
KW - Digitalisierung
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654056
DO - https://doi.org/10.1016/j.dib.2025.112436
VL - 65
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-65405
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos, José Antonio
T1 - Experimental volumetric hydrogen uptake determination at 77 K of commercially available metal-organic framework materials
N2 - Storage is still limiting the implementation of hydrogen as an energy carrier to integrate the intermittent operation of renewable energy sources. Among different solutions to the currently used compressed or liquified hydrogen systems, physical adsorption at cryogenic temperature in porous materials is an attractive alternative due to its fast and reversible operation and the resulting reduction in storage pressure. The feasibility of cryoadsorption for hydrogen storage depends mainly on the performance of the used materials for the specific application, where metal-organic frameworks or MOFs are remarkable candidates. In this work, gravimetric and volumetric hydrogen uptakes at 77 K and up to 100 bar of commercially available MOFs were measured since these materials are made from relatively cheap and accessible building blocks. These materials also show relatively high porous properties and are currently near to large-scale production. The measuring device was calibrated at different room temperatures to calculate an average correction factor and standard deviation so that the correction deviation is included in the measurement error for better comparability with different measurements. The influence of measurement conditions was also studied, concluding that the available adsorbing area of material and the occupied volume of the sample are the most critical factors for a reproducible measurement, apart from the samples’ preparation before measurement. Finally, the actual volumetric storage density of the used powders was calculated by directly measuring their volume in the analysis cell, comparing that value with the maximum volumetric uptake considering the measured density of crystals. From this selection of commercial MOFs, the materials HKUST-1, PCN-250(Fe), MOF-177, and MOF-5 show true potential to fulfill a volumetric requirement of 40 g·L−1 on a material basis for hydrogen storage systems without further packing of the powders.
KW - Hydrogen adsorption
KW - Commercial metal-organic frameworks
KW - Hydrogen uptake reproducibility
KW - Volumetric uptake
KW - Packing density
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542215
DO - https://doi.org/10.3390/c8010005
SN - 2311-5629
VL - 8
IS - 1
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-54221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Han, Ying
A1 - Rosalie, Julian
A1 - Radners, Jan
A1 - Madia, Mauro
A1 - von Hartrott, Philipp
A1 - Skrotzki, Birgit
T1 - Influence of test temperature and test frequency on fatigue life of aluminum alloy EN AW-2618A
N2 - The aluminum alloy EN AW-2618A is a high-strength, precipitation-hardened material developed for applications at elevated temperatures. In service, components such as radial compressor wheels and pistons are exposed to thermal conditions that cause microstructural overaging, leading to mechanical softening. With future exhaust gas turbochargers expected to operate at temperatures up to 230°C and with increasing demands for efficiency and compression ratio, reliable data on fatigue behavior under these conditions is essential but currently lacking. This study aims to close this gap by conducting fully reversed (R = −1) high-cycle fatigue (HCF) tests at room temperature and at 230°C on specimens in an overaged condition (1000 h at 230°C), simulating the degradation that occurs in service due to the coarsening of the strengthening S-phase. Additionally, the influence of test frequency on fatigue performance is investigated.
KW - High-cycle fatigue
KW - EN AW-2618A
KW - High-temperature
KW - Recipitation hardening
KW - Overaging
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658655
DO - https://doi.org/10.1002/adem.202503187
SN - 1527-2648
SP - 1
EP - 14
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-65865
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heeger, Felix
A1 - Bourne, E. C.
A1 - Wurzbacher, C.
A1 - Funke, E.
A1 - Lipzen, A.
A1 - He, G.
A1 - Ng, V.
A1 - Grigoriev, I. V.
A1 - Schlosser, D.
A1 - Monaghan, M. T.
T1 - Evidence for lignocellulose-decomposing enzymes in the genome and transcriptome of the aquatic hyphomycete Clavariopsis aquatica
N2 - Fungi are ecologically outstanding decomposers of lignocellulose. Fungal lignocellulose degradation is prominent in saprotrophic Ascomycota and Basidiomycota of the subkingdom Dikarya. Despite ascomycetes dominating the Dikarya inventory of aquatic environments, genome and transcriptome data relating to enzymes involved in lignocellulose decay remain limited to terrestrial representatives of these phyla. We sequenced the genome of an exclusively aquatic ascomycete (the aquatic hyphomycete Clavariopsis aquatica), documented the presence of genes for the modification of lignocellulose and its constituents, and compared differential gene expression between C. aquatica cultivated on lignocellulosic and sugar-rich substrates. We identified potential peroxidases, laccases, and cytochrome P450 monooxygenases, several of which were differentially expressed when experimentally grown on different substrates. Additionally, we found indications for the regulation of pathways for cellulose and hemicellulose degradation. Our results suggest that C. aquatica is able to modify lignin to some extent, detoxify aromatic lignin constituents, or both. Such characteristics would be expected to facilitate the use of carbohydrate components of lignocellulose as carbon and energy sources.
KW - Aquatic fungi
KW - Differential expression
KW - Lignocellulose
KW - Laccase
KW - RNA-Seq
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536843
DO - https://doi.org/10.3390/jof7100854
SN - 2309-608X
VL - 7
IS - 10
SP - 2
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-53684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pérez Blanes, H.
A1 - Ghiasi, P.
A1 - Sandkühler, J.
A1 - Yesilcicek, Yasemin
A1 - Pentzien, Simone
A1 - Conradi, Andrea
A1 - Prinz, Carsten
A1 - Al-Sabbagh, Dominik
A1 - Thünemann, Andreas
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation
N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts.
KW - Multi-principal element alloys
KW - Chemically Complex Materials
KW - CCMat
KW - Electrocatalysis
KW - Carbon dioxide reduction
KW - Pulsed laser ablation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594018
DO - https://doi.org/10.1016/j.jmrt.2023.05.143
VL - 24
SP - 9434
EP - 9440
PB - Elsevier BV
AN - OPUS4-59401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ganose, Alex M.
A1 - Sahasrabuddhe, Hrushikesh
A1 - Asta, Mark
A1 - Beck, Kevin
A1 - Biswas, Tathagata
A1 - Bonkowski, Alexander
A1 - Bustamante, Joana
A1 - Chen, Xin
A1 - Chiang, Yuan
A1 - Chrzan, Daryl C.
A1 - Clary, Jacob
A1 - Cohen, Orion A.
A1 - Ertural, Christina
A1 - Gallant, Max C.
A1 - George, Janine
A1 - Gerits, Sophie
A1 - Goodall, Rhys E. A.
A1 - Guha, Rishabh D.
A1 - Hautier, Geoffroy
A1 - Horton, Matthew
A1 - Inizan, T. J.
A1 - Kaplan, Aaron D.
A1 - Kingsbury, Ryan S.
A1 - Kuner, Matthew C.
A1 - Li, Bryant
A1 - Linn, Xavier
A1 - McDermott, Matthew J.
A1 - Mohanakrishnan, Rohith Srinivaas
A1 - Naik, Aakash A.
A1 - Neaton, Jeffrey B.
A1 - Parmar, Shehan M.
A1 - Persson, Kristin A.
A1 - Petretto, Guido
A1 - Purcell, Thomas A. R.
A1 - Ricci, Francesco
A1 - Rich, Benjamin
A1 - Riebesell, Janosh
A1 - Rignanese, Gian-Marco
A1 - Rosen, Andrew S.
A1 - Scheffler, Matthias
A1 - Schmidt, Jonathan
A1 - Shen, Jimmy-Xuan
A1 - Sobolev, Andrei
A1 - Sundararaman, Ravishankar
A1 - Tezak, Cooper
A1 - Trinquet, Victor
A1 - Varley, Joel B.
A1 - Vigil-Fowler, Derek
A1 - Wang, Duo
A1 - Waroquiers, David
A1 - Wen, Mingjian
A1 - Yang, Han
A1 - Zheng, Hui
A1 - Zheng, Jiongzhi
A1 - Zhu, Zhuoying
A1 - Jain, Anubhav
T1 - Atomate2: Modular workflows for materials science
N2 - High-throughput density functional theory (DFT) calculations have become a vital element of computational materials science, enabling materials screening, property database generation, and training of “universal” machine learning models. While several software frameworks have emerged to support these computational efforts, new developments such as machine learned force fields have increased demands for more flexible and programmable workflow solutions. This manuscript introduces atomate2, a comprehensive evolution of our original atomate framework, designed to address existing limitations in computational materials research infrastructure. Key features include the support for multiple electronic structure packages and interoperability between them, along with generalizable workflows that can be written in an abstract form irrespective of the DFT package or machine learning force field used within them. Our hope is that atomate2's improved usability and extensibility can reduce technical barriers for high-throughput research workflows and facilitate the rapid adoption of emerging methods in computational material science.
KW - Automation
KW - Materials design
KW - DFT workflows
KW - Phonons
KW - Thermal conductivity
KW - Bonding analysis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-635759
DO - https://doi.org/10.1039/d5dd00019j
SN - 2635-098X
SP - 1
EP - 30
PB - Royal Society of Chemistry (RSC)
CY - Cambridge
AN - OPUS4-63575
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical studies of process porosity suppression by magnetohydrodynamic technology during the laser beam welding of aluminum alloy
N2 - Magnetohydrodynamic (MHD) technology is acknowledged as a promising method for mitigating the porosity defects in laser-welded joints of aluminum alloys. A transient 3D multi-physical numerical model of laser beam welding (LBW), coupled with the MHD and oscillating metal vapor plume model, is developed to study the suppression mechanisms of process porosity by an external magnetic field. The experimental results demonstrate that the porosity ratio is reduced by 93.5 % as the oscillating magnetic field is applied. This significant reduction confirms the effectiveness of the MHD technology in suppressing porosity defects. A downward time-averaged Lorentz force is induced in the weld pool, which affects the fluid flow pattern and the weld pool profile. The change of the flowing pattern in the weld pool by the magnetic field does not always have a positive effect on the porosity suppression. In addition, an analytical model shows that the bubble escape window is expanded by 62 % under the effect of the oscillating magnetic field. The additional upward velocity provided by the electromagnetic expulsive force on the bubbles and the change of weld pool profile are considered favorable factors in eliminating the porosity defects. The numerical and analytical model developed for analyzing the bubble escape window have been validated by experimental results.
KW - Laser beam welding
KW - Aluminum alloy
KW - Process porosity defects
KW - Magnetohydrodynamic technology
KW - Bubble escape
KW - Numerical simulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637642
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2025.127525
SN - 0017-9310
VL - 253
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-63764
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, Max
A1 - Yang, Keke
A1 - Meschut, Gerson
A1 - Rethmeier, Michael
T1 - Occurrence and avoidance of liquid metal embrittlement in resistance spot welding of springback-afflicted deep-drawn components
N2 - This study investigates the occurrence and mitigation of liquid metal embrittlement occurring during resistance spot welding in deep-drawn automotive components, specifically focusing on an S-Rail made from advanced high-strength steel. A simulation-based liquid metal embrittlement risk criterion based on local major component stresses was established and used to quantify and compare liquid metal embrittlement risks between different tests. Experimental and numerical analyses were conducted, revealing that springback significantly impacts liquid metal embrittlement formation. Adjustments in electrode geometry and hold time post-welding were found to mitigate liquid metal embrittlement risks. The effects of stack-up configuration and related parameter settings on liquid metal embrittlement occurrence were identified and liquid metal embrittlement was effectively prevented across both stack-up configurations. These findings advance the understanding of liquid metal embrittlement mechanisms and provide practical approaches to enhance the spot weld quality in AHSS-based body-in-whites.
KW - Liquid metal embrittlement
KW - Crack
KW - Advanced high-strength steels
KW - Resistance spot welding
KW - Weld current
KW - Heat input
KW - Simulation
KW - Springback
KW - Deep drawing
KW - S-Rail
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-636577
DO - https://doi.org/10.1177/13621718251340452
SN - 1362-1718
SP - 1
EP - 9
PB - SAGE Publications
AN - OPUS4-63657
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Multi-refining effects of an AC electromagnetic field on the microstructure in AA5754 laser beam welding
N2 - Fine-grain structure is beneficial to the mechanical properties of the joint. Different kinds of grain and sub-grain structures refined by magnetic field during laser beam welding of AA5754 aluminum alloy are analyzed in this manuscript, and the influences of different magnetic field parameters (magnetic flux density and frequency) in these refining effects are also studied. Using the scanning electron microscope (SEM), the sub-grain structure near the fusion line was obtained, and it was found that the branching promotion and branches refinement can be achieved by the magnetic field. The branches become finer with the magnetic flux density or frequency increases, and this effect is stronger in the dendritic region than in the equiaxed region. The results of electron backscatter diffraction (EBSD) in the equiaxed region show that a high-frequency magnetic field can greatly reduce the average grain size, while a low-frequency one has little effect. A phenomenological nucleation model based on dendrite fragmentation theory was established, and it was introduced into the phase field model to analyze the equiaxed grains evolution process. In addition, another refinement mechanism was also observed. The periodic solidification pattern caused by the unstable solidification in the molten pool can refine the grains, and the magnetic field promotes this kind of grain refinement by promoting the solidification period.
KW - Laser beam welding
KW - Magnetic field
KW - Aluminum alloy
KW - Crystal branch development
KW - Periodic solidification pattern
KW - Grain refinement
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637222
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2025.127509
SN - 0017-9310
VL - 252
SP - 1
EP - 16
PB - Elsevier Ltd.
AN - OPUS4-63722
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Riebesell, Janosh
A1 - Goodall, Rhys E. A.
A1 - Benner, Philipp
A1 - Chiang, Yuan
A1 - Deng, Bowen
A1 - Ceder, Gerbrand
A1 - Asta, Mark
A1 - Lee, Alpha A.
A1 - Jain, Anubhav
A1 - Persson, Kristin A.
T1 - A framework to evaluate machine learning crystal stability predictions
N2 - The rapid adoption of machine learning in various scientific domains calls for the development of best practices and community agreed-upon benchmarking tasks and metrics. We present Matbench Discovery as an example evaluation framework for machine learning energy models, here applied as pre-filters to first-principles computed data in a high-throughput search for stable inorganic crystals. We address the disconnect between (1) thermodynamic stability and formation energy and (2) retrospective and prospective benchmarking for materials discovery. Alongside this paper, we publish a Python package to aid with future model submissions and a growing online leaderboard with adaptive user-defined weighting of various performance metrics allowing researchers to prioritize the metrics they value most. To answer the question of which machine learning methodology performs best at materials discovery, our initial release includes random forests, graph neural networks, one-shot predictors, iterative Bayesian optimizers and universal interatomic potentials. We highlight a misalignment between commonly used regression metrics and more task-relevant classification metrics for materials discovery. Accurate regressors are susceptible to unexpectedly high false-positive rates if those accurate predictions lie close to the decision boundary at 0 eV per atom above the convex hull. The benchmark results demonstrate that universal interatomic potentials have advanced sufficiently to effectively and cheaply pre-screen thermodynamic stable hypothetical materials in future expansions of high-throughput materials databases.
KW - Machine Learning
KW - Interatomic Potentials
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637139
DO - https://doi.org/10.1038/s42256-025-01055-1
SN - 2522-5839
VL - 7
IS - 6
SP - 836
EP - 847
PB - Springer Science and Business Media LLC
AN - OPUS4-63713
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Amariamir, Sasan
A1 - George, Janine
A1 - Benner, Philipp
T1 - SynCoTrain: a dual classifier PU-learning framework for synthesizability prediction
N2 - Material discovery is a cornerstone of modern science, driving advancements in diverse disciplines from biomedical technology to climate solutions. Predicting synthesizability, a critical factor in realizing novel materials, remains a complex challenge due to the limitations of traditional heuristics and thermodynamic proxies. While stability metrics such as formation energy offer partial insights, they fail to account for kinetic factors and technological constraints that influence synthesis outcomes. These challenges are further compounded by the scarcity of negative data, as failed synthesis attempts are often unpublished or context-specific. We present SynCoTrain, a semi-supervised machine learning model designed to predict the synthesizability of materials. SynCoTrain employs a co-training framework leveraging two complementary graph convolutional neural networks: SchNet and ALIGNN. By iteratively exchanging predictions between classifiers, SynCoTrain mitigates model bias and enhances generalizability. Our approach uses Positive and Unlabeled (PU) learning to address the absence of explicit negative data, iteratively refining predictions through collaborative learning. The model demonstrates robust performance, achieving high recall on internal and leave-out test sets. By focusing on oxide crystals, a well-characterized material family with extensive experimental data, we establish SynCoTrain as a reliable tool for predicting synthesizability while balancing dataset variability and computational efficiency. This work highlights the potential of co-training to advance high-throughput materials discovery and generative research, offering a scalable solution to the challenge of synthesizability prediction.
KW - Synthesizability
KW - Accelerated Materials Design
KW - Materials Acceleration Platforms
KW - Materials Design
KW - Materials Discovery
KW - Co-training
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-637907
DO - https://doi.org/10.1039/D4DD00394B
SN - 2635-098X
VL - 4
IS - 6
SP - 1437
EP - 1448
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-63790
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Fasselt, Janek Maria
A1 - Klötzer-Freese, Christian
A1 - Kruse, Tobias
A1 - Kleba-Ehrhardt, Rafael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Recycling nickel aluminium bronze grinding chips to feedstock for directed energy deposition via impact whirl milling: Investigation on processability, microstructure and mechanical properties
N2 - During the production of ship propellers, considerable quantities of grinding chips from nickel aluminium bronze are produced. This paper examines the mechanical comminution of such chips via impact whirl milling and the utilization of two chip-powder batches as feedstock for a laser-based directed energy deposition process. The materials are characterized via digital image analysis, standardized flowability tests, scanning electron microscopy and energy dispersive X-ray spectroscopy and are compared to conventional, gas atomized powder. The specimens deposited via directed energy deposition are analyzed for density, hardness and microstructure and tensile properties for vertical and horizontal build up directions are compared. At elevated mill rotation speeds, the comminution with impact whirl milling produced rounded particles, favorable flow properties and particle size distribution, making them suitable to deposit additive specimens. The microstructure exhibited characteristic martensitic phases due to the high cooling rates of the additive manufacturing process. The presence of ceramic inclusions was observed in both the powder and on the tensile fracture surfaces, partly impairing the mechanical properties. However, specimens in the vertical build-up direction (Z) showed competitive tensile results, with 775 MPa in tensile strength, 455 MPa in yield strength and 12.6 % elongation at break. The findings of this study indicate that recycling of machining chips to additive manufacturing feedstock can be a viable option for reducing material costs and environmental impact.
KW - Nickel aluminium bronze
KW - Grinding chips
KW - Recycling
KW - Directed energy deposition
KW - Material characterization
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-633442
DO - https://doi.org/10.1016/j.addma.2025.104804
SN - 2214-8604
VL - 105
SP - 1
EP - 9
PB - Elsevier BV
AN - OPUS4-63344
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Klement, Oliver
A1 - Sander, Steffen
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Recycling of Stainless Steel Milling Chips for Additive Manufacturing: A Three-Stage Comminution Approach Using a Fine Impact Mill
N2 - The production of conventional metal powders for additive manufacturing process is energy intensive and costly. This study introduces a sustainable alternative by recycling stainless steel milling chips as feedstock for laser-powder directed energy deposition. The recycling process employs a three-stage mechanical comminution method utilizing a fine impact mill UPZ100 from Hosokawa Alpine AG. Characterization of the resulting powders is conducted through particle morphology analysis, flowability tests, and mechanical property assessments. The chip-derived powders exhibit comparable aspect ratios and sphericity to conventional water atomized powders, though with reduced flowability due to a pronounced fine fraction content. Elevated levels of oxides are observed, leading to the formation of an oxide layer on specimen blocks, without impairing the mechanical properties. Analyses of porosity, microstructure, and hardness indicate no significant differences when compared to conventional powders from water or gas atomization. This recycling approach not only mitigates waste but also enhances the potential for a circular and sustainable manufacturing process in the additive manufacturing industry and beyond.
KW - Directed Energy Deposition
KW - Recycling
KW - Stainless steel
KW - Comminution
KW - Powder characteristics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652037
DO - https://doi.org/10.1088/1757-899X/1332/1/012014
SN - 1757-8981
VL - 1332
IS - 1
SP - 1
EP - 7
PB - IOP Publishing
AN - OPUS4-65203
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Seitz, Georg
A1 - Bantle, Patrick
A1 - Biegler, Max
A1 - Elsner, Beatrix A. M.
A1 - Rethmeier, Michael
T1 - An Inherent Strain Method Using Progressive Element Activation for Fast Distortion Calculation in Directed Energy Deposition
N2 - The finite element analysis (FEA) simulation of directed energy deposition (DED) processes offers many potential cost savings during the build job optimization process, through, e.g., distortion predictions. However, the biggest challenge is the long calculation time, frequently exceeding the actual build time. One way of simplifying the simulation with the aim of reducing the calculation times is the inherent strain method. While this method is already used commercially in the simulation of powder bed-based processes and conventional welding technologies, its use in DED is still the subject of research. In this work, an inverse determination of an inherent strain is carried out on a 20-layer-high, single-track-wide wall, common theories are reviewed, and an approach based on thermal strain is introduced. As a result, the calculation time could be reduced by 83% and the accuracy remained at 92%.
KW - Inherent strain method
KW - Simulation
KW - Finite element analysis
KW - Directed energy deposition
KW - Additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622595
DO - https://doi.org/10.3390/met14121338
SN - 2075-4701
VL - 14
IS - 12
SP - 1
EP - 12
PB - MDPI
AN - OPUS4-62259
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindrachuk, Vitaliy
A1 - Fedelich, Bernard
A1 - Rehmer, Birgit
A1 - Peter, Frauke
T1 - Computational methods for lifetime prediction of metallic components under high-temperature fatigue
N2 - The issue of service life prediction of hot metallic components subjected to cyclic loadings is addressed. Two classes of lifetime models are considered, namely, the incremental lifetime rules and the parametric models governed by the fracture mechanics concept. Examples of application to an austenitic cast iron are presented. In addition, computational techniques to accelerate the time integration of the incremental models throughout the fatigue loading history are discussed. They efficiently solve problems where a stabilized response of a component is not observed, for example due to the plastic strain which is no longer completely reversed and accumulates throughout the fatigue history. The performance of such an accelerated Integration technique is demonstrated for a finite element simulation of a viscoplastic solid under repeating loading–unloading cycles.
KW - Fatigue
KW - Incremental lifetime models
KW - Finite element analysis
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-481215
UR - https://www.mdpi.com/2075-4701/9/4/390
DO - https://doi.org/10.3390/met9040390
SN - 2075-4701
VL - 9
IS - 4
SP - 390, 1
EP - 24
PB - mdpi
CY - Basel, Switzerland
AN - OPUS4-48121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pittrich, Tim
A1 - Peters, S.
A1 - Meschke, G.
A1 - Weise, Frank
A1 - Stelzner, Ludwig
T1 - Thermally induced moisture transport in concrete with diffeent types of blended Portland cement studied by 1H‑NMR relaxometry
N2 - Clinker-reduced cements are gaining in popularity as part that utilization of these cements negatively influence the fie-induced spalling behavior of concrete, which is highly influenced y thermohydraulic damage mechanisms. Therefore, thermally induced moisture transport in normal strength concretes made with dif-ferent types of blended cements (CEM I, CEM II/A-LL, CEM III/A and CEM II/B-Q) was investigated by means of 1H-NMR relaxometry in combination with supportive side investigations concerning permeabil-ity and porosity. In addition, a numerical model was used to analyze in-situ moisture development during high temperature exposure. The results show that the cement type influences bth initial moisture content and pore size-specific moiture distribution. This was primarily reflected in an inceased water content in CEM III/A and CEM II/B-Q concretes as well as a comparable high gel pore water fraction in CEM II/B-Q concrete before heating. After heating, a similar degree of pore coarsening from gel to capillary pore was observed in all samples. Although the measure-ments were only conducted after, not during, high temperature exposure, the depth of the drying front and the extent of the moisture clog could be deter-mined. With the additional numerical analysis, it can be assumed that during high temperature load, the drying front is less advanced and the moisture clog even more pronounced. In conclusion, it can be stated that the increased spalling susceptibility in blended cement concrete is caused by the lower initial perme-ability and increased moisture content.
KW - Fire concrete spalling
KW - Thermally induced moisture transport
KW - Blended cements
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659015
DO - https://doi.org/10.1617/s11527-026-03025-4
VL - 59
IS - 133
SP - 1
EP - 20
PB - Springer
CY - Dordrecht
AN - OPUS4-65901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Ghnatios, C.
A1 - Klawoon, Alexander
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
A1 - Robens-Radermacher, Annika
T1 - Efficient bead-on-plate weld model for parameter estimation towards effective wire arc additive manufacturing simulation
N2 - Despite the advances in hardware and software techniques, standard numerical methods fail in providing real-time simulations, especially for complex processes such as additive manufacturing applications. A real-time simulation enables process control through the combination of process monitoring and automated feedback, which increases the flexibility and quality of a process. Typically, before producing a whole additive manufacturing structure, a simplified experiment in the form of a beadon-plate experiment is performed to get a first insight into the process and to set parameters suitably. In this work, a reduced order model for the transient thermal problem of the bead-on-plate weld simulation is developed, allowing an efficient model calibration and control of the process. The proposed approach applies the proper generalized decomposition (PGD) method, a popular model order reduction technique, to decrease the computational effort of each model evaluation required multiple times in parameter estimation, control, and optimization. The welding torch is modeled by a moving heat source, which leads to difficulties separating space and time, a key ingredient in PGD simulations. A novel approach for separating space and time is applied and extended to 3D problems allowing the derivation of an efficient separated representation of the temperature.
The results are verified against a standard finite element model showing excellent agreement. The reduced order model is also leveraged in a Bayesian model parameter estimation setup, speeding up calibrations and ultimately leading to an optimized real-time simulation approach for welding experiment using synthetic as well as real measurement data.
KW - Proper generalized decomposition
KW - Model order reduction
KW - Hardly separable problem
KW - Additive manufacturing
KW - Model calibration
KW - Wire arc additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596502
DO - https://doi.org/10.1007/s40194-024-01700-0
SN - 0043-2288
SP - 1
EP - 18
PB - Springer
AN - OPUS4-59650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Churiaque Bermejo, C.
A1 - Sánchez-Amaya, J. M.
A1 - Porrúa-Lara, M.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - The Effects of HLAW Parameters for One Side T-Joints in 15 mm Thickness Naval Steel
N2 - The present contribution is the first research reporting full penetration HLAW joints in 15 mm thick EH36 steel butt T-welds with square grooves on 2F welding position by single-sided welding. The effects of welding parameters were investigated to increase the quality of the joints.
Conditions leading to defect-free full penetration welds fulfilling naval regulations includes a laser power of 12.5 kW, a welding speed of 1.6 m/min and the vertical laser offset distance from the flange of 1 mm. Advanced characterization of selected welds included a microstructural identification by optical microscopy, SEM, and XRD, revealing the presence of acicular, polygonal and Widmanstätten ferrite, lath martensite, and some retained austenite at FZ. Hardness and microhardness mapping tests showed values of 155 HV at base metal and 200 to 380 HV at the fusion zone connecting the web to the flange.
KW - Ship building
KW - Laser beam welding
KW - Hybrid laser arc welding
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523931
DO - https://doi.org/10.3390/met11040600
VL - 11
IS - 4
SP - 600
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-52393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Altenburg, Simon
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Maierhofer, Christiane
T1 - In-situ monitoring of a laser metal deposition (LMD) process: comparison of MWIR, SWIR and high-speed NIR thermography
N2 - Additive manufacturing offers a range of novel applications. However, the manufacturing process is complex and the production of almost defect-free parts with high reliability and durability is still a challenge. Thermography is a valuable tool for process surveillance, especially in metal additive manufacturing processes. The high process temperatures allow one to use cameras usually operating in the visible spectral range. Here, we compare the results of measurements during the manufacturing process of a commercial laser metal deposition setup using a mid wavelength infrared camera with those from a short wavelength infrared camera and those from a visual spectrum high-speed camera with band pass filter in the near infrared range.
KW - Additive Manufacturing
KW - Process monitoring
KW - Thermography
KW - LMD
KW - Metal
KW - MWIR
KW - SWIR
KW - NIR
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516318
DO - https://doi.org/10.1080/17686733.2020.1829889
VL - 19
IS - 2
SP - 97
EP - 114
PB - Taylor & Francis Group
CY - London, UK
AN - OPUS4-51631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Karkhin, V.
A1 - Rethmeier, Michael
T1 - On the relationship between the bulge effect and the hot cracking formation during deep penetration laser beam welding
N2 - Recent studies have confirmed the widening of the weld pool interface, known as a bulge effect, during deep penetration high power laser beam welding. The link between such geometric particularities of the weld pool shape and the hot cracking phenomena is significant. The present work seeks to extend the level of understanding by investigating their relationship. A coupled multiphysics, multiscale numerical framework is developed, comprising a series of subsequent analyses. The study examines the influences of the bulge on the three most dominant effects causing hot cracking, namely the thermal cycles, the mechanical loading, and the local microstructure. The bulge in the weld pool shape forms approximately in the middle of the plate, thus correlating with the location of hot cracking. It increases the hot cracking susceptibility by enhancing the three dominant effects. The numerical results are backed up by experimental data.
T2 - 11th CIRP Conference on Photonic Technologies [LANE 2020]
KW - Hot cracking
KW - Bulge effect
KW - Numerical modelling
KW - Laser beam welding
KW - Deep penetration
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512783
DO - https://doi.org/10.1016/j.procir.2020.09.002
SN - 2212-8271
VL - 94
SP - 5
EP - 10
PB - Elsevier B.V.
CY - Amsterdam [u.a.]
AN - OPUS4-51278
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Artinov, Antoni
A1 - Gumenyuk, Andrey
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical simulation on the origin of solidification cracking in laser welded thick-walled structures
N2 - One of the main factors affecting the use of lasers in the industry for welding thick structures is the process accompanying solidification cracks. These cracks mostly occurring along the welding direction in the welding center, and strongly affect the safety of the welded components. In the present study, to obtain a better understanding of the relation between the weld pool geometry, the stress distribution and the solidification cracking, a three-dimensional computational fluid dynamic (CFD) model was combined with a thermo-mechanical model. The CFD model was employed to analyze the flow of the molten metal in the weld pool during the laser beam welding process. The weld pool geometry estimated from the CFD model was used as a heat source in the thermal model to calculate the temperature field and the stress development and distributions. The CFD results showed a bulging region in the middle depth of the weld and two narrowing areas separating the bulging region from the top and bottom surface. The thermo-mechanical simulations showed a concentration of tension stresses, transversally and vertically, directly after the solidification during cooling in the region of the solidification cracking.
T2 - 27TH INTERNATIONAL CONFERENCE ON METALLURGY AND MATERIALS - METAL 2018
CY - Brno, Czech Republic
DA - 23.05.2018
KW - Laser beam welding
KW - Weld pool
KW - Full penetration
KW - Finite element method (FEM)
KW - CFD model
KW - Numerical simulation
KW - Solidification cracking
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-450595
DO - https://doi.org/10.3390/met8060406
SN - 2075-4701
VL - 8
IS - 6
SP - 406, 1
EP - 15
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-45059
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Uhlmann, E.
A1 - Düchting, J.
A1 - Petrat, T.
A1 - Krohmer, E.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Effects on the distortion of Inconel 718 components along a hybrid laser‑based additive manufacturing process chain using laser powder bed fusion and laser metal deposition
N2 - The combination of laser powder bed fusion (LPBF), known for its geometrical freedom and accuracy, and the nozzle-based laser metal deposition process (LMD), known for its high build-up rates, has great potential to reduce the additive manufacturing times for large metallic parts. For the industrial application of the LPBF-LMD hybrid process chain, it is necessary to investigate the infuence of the LMD process on the LPBF substrate. In addition, the build plate material also has a signifcant impact on the occurrence of distortion along the additive manufacturing process chain. In the literature, steel build plates are often used in laser-based additive manufacturing processes of Inconel 718, since a good metallurgical Bonding can be assured whilst reducing costs in the production and restoration of the build plates. This paper examines the distortion caused by LMD material deposition and the infuence of the build plate material along the hybrid additive manufacturing process chain. Twin cantilevers are manufactured by LPBF and an additional layer is subsequently deposited with LMD. The distortion is measured in the as-built condition as well as after heat treatment. The efect of diferent LMD hatch strategies on the distortion is determined. The experiments are conducted using the nickel-base alloy Inconel 718. The results show a signifcant infuence of LMD path strategies on distortion, with shorter tool paths leading to less distortion. The remaining distortion after heat treatment is considerably dependent on the material of the build plate.
KW - Laser powder bed fusion
KW - Directed energy deposition
KW - Laser metal deposition
KW - Distortion
KW - Heat treatment
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-521439
DO - https://doi.org/10.1007/s40964-021-00171-9
SP - 1
EP - 10
PB - Springer-Verlag GmbH
CY - Heidelberg
AN - OPUS4-52143
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaumann, P.
A1 - Schürmann, K.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Experimental investigations on the fatigue resistance of automatically welded tubular X-joints for jacket support structures
N2 - The development within the offshore wind sector towards more powerful turbines combined with increasing water depth for new wind parks is challenging both the designer as well as the manufacturer of bottom fixed support structures. Besides XL-monopiles, the market developed an innovative and economic jacket support structure which is based on automatically manufactured tubular joints combined with standardized pipes. Besides the improvements for a serial manufacturing process the automatically welded tubular joints show a great potential in terms of fatigue resistance e.g. due to a smooth weld geometry without sharp notches. However, these benefits are not considered yet within the fatigue design process of automatically manufactured jacket substructures according to current standards due to the lack of suitable S-N curves. Therefore, 32 axial fatigue tests on single and double-sided automatically welded tubular X-joints have been performed to determine a new hot spot stress related S-N curve. Based on these constant amplitude fatigue tests a new S-N curve equal to a FAT 126 curve was computed which implicitly includes the benefits of the automatically welding procedure.
T2 - EERA Deep Wind 2020
CY - Trondheim, Norway
DA - 15.01.2020
KW - Notch stress approach
KW - Fatigue tests
KW - Automated manufacturing
KW - Tubular X-joints
KW - Structural stress approach
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518509
DO - https://doi.org/10.1088/1742-6596/1669/1/012022
VL - 1669
SP - 012022
PB - IOP Publishing Ltd
AN - OPUS4-51850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Hybrid laser-arc welding of thick-walled pipe segments with optimization of the end crater
N2 - The study deals with the application of the high-power hybrid-laser arc welding process on up to 15 mm thick pipe segments with the intention to avoid end crater imperfections during closing of the circumferential welds, where the pipes were turned during welding in 1G- and 2Gpositions.
Different techniques such as laser power ramp-down, abrupt switch-off of the laser power and change of the magnification of the laser spot diameter and defocusing of the laser beam relative to the workpiece were tested to remove the laser energy from the process. It could be shown that a high defocusing of the optic system above 40 mm with a resulting beam diameter > 2.9 mm in a short overlap length of approx.
20 mm leads to the formation of a cup-shaped weld seam, which is preferred for avoidance of cracks and pores in the end crater. A laser optics with motor-driven lens system was used for the welding experiments to defocuse the laser beam without changing the position of the arc.
KW - Hybrid laser-arc welding
KW - Circumferential weld
KW - Thick-walled steel
KW - Single-pass welding
KW - End crater
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513260
DO - https://doi.org/10.1016/j.procir.2020.09.106
VL - 94
SP - 676
EP - 679
PB - Elsevier B.V.
AN - OPUS4-51326
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical study of additional element transport in wire feed laser beam welding
N2 - The transport phenomena in the wire feed laser beam welding are investigated numerically. A three-dimensional transient heat transfer and fluid flow model coupled with free surface tracing and element transport is developed. A ray-tracing method with local grid refinement algorithm is used to calculate the multiple reflections and Fresnel absorption on the keyhole wall. The filler material flows backward along the lateral side of the weld pool, and subsequently flows forward along the longitudinal plane. The occurrence of the bulging phenomenon may further prevent the downward transfer of the additional elements to the root of the weld pool.
KW - Laser beam welding
KW - Element transport
KW - Filler wire
KW - Numerical modelling
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513271
DO - https://doi.org/10.1016/j.procir.2020.09.129
VL - 94
SP - 722
EP - 725
PB - Elsevier B.V.
AN - OPUS4-51327
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Schaumann, P.
A1 - Schürmann, K.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Automatically Welded Tubular X Joints for Jacket Substructures – Prediction of the Technical Fatigue Crack Location
N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented.
T2 - Nordic Steel 2019
CY - Copenhagen, Denmark
DA - 18.09.2019
KW - Automated arc welding
KW - Fatigue tests
KW - Tubular X-joints
KW - Technical crack detection
KW - Local fatigue approaches
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518490
DO - https://doi.org/10.1002/cepa.1140
VL - 3
IS - 3-4
SP - 823
EP - 828
PB - Wiley-VCH Verlag GmbH on behalf of Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG
CY - Berlin
AN - OPUS4-51849
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hildebrandt, R.
A1 - Seifert, M.
A1 - George, Janine
A1 - Blaurock, S.
A1 - Botti, S.
A1 - Krautscheid, H.
A1 - Grundmann, M.
A1 - Sturm, C.
T1 - Determination of acoustic phonon anharmonicities via second-order Raman scattering in CuI
N2 - We demonstrate the determination of anharmonic acoustic phonon properties via second-order Raman scattering exemplarily on copper iodide single crystals. The origin of multi-phonon features from the second-order Raman spectra was assigned by the support of the calculated 2-phonon density of states. In this way, the temperature dependence of acoustic phonons was determined down to 10 K. To determine independently the harmonic contributions of respective acoustic phonons, density functional theory in quasi-harmonic approximation was used. Finally, the anharmonic contributions were determined. The results are in agreement with earlier publications and extend CuI’s determined acoustic phonon properties to lower temperatures with higher accuracy. This approach demonstrates that it is possible to characterize the acoustic anharmonicities via Raman scattering down to zero-temperature renormalization constants of at least 0.1 cm⁻¹.
KW - Thermoelectrics
KW - Thermal transport
KW - Phonon interactions
KW - Density functional theory
KW - Phonons
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593164
DO - https://doi.org/10.1088/1367-2630/ad1141
SN - 1367-2630
VL - 25
IS - 12
SP - 1
EP - 12
PB - IOP Publishing
CY - London
AN - OPUS4-59316
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prabitz, Konstantin Manuel
A1 - Antretter, Thomas
A1 - Rethmeier, Michael
A1 - El-Sari, Bassel
A1 - Schubert, Holger
A1 - Hilpert, Benjamin
A1 - Gruber, Martin
A1 - Sierlinger, Robert
A1 - Ecker, Werner
T1 - Numerical and experimental assessment of liquid metal embrittlement in externally loaded spot welds
N2 - Zinc-based surface coatings are widely applied with high-strength steels in automotive industry. Some of these base materials show an increased brittle cracking risk during loading. It is necessary to examine electrogalvanized and uncoated samples of a high strength steel susceptible to liquid metal embrittlement during spot welding with applied external load. Therefore, a newly developed tensile test method with a simultaneously applied spot weld is conducted. A fully coupled 3D electrical, thermal, metallurgical and mechanical finite element model depicting the resistant spot welding process combined with the tensile test conducted is mandatory to correct geometric influences of the sample geometry and provides insights into the sample’s time dependent local loading. With increasing external loads, the morphology of the brittle cracks formed is affected more than the crack depth. The validated finite element model applies newly developed damage indicators to predict and explain the liquid metal embrittlement cracking onset and development as well as even ductile failure.
KW - Resistance spot welding
KW - Finite element simulation
KW - Advanced high-strength steel
KW - Liquid metal embrittlement
KW - Damage prediction
KW - Tensile resistance spot welding experiment
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594848
DO - https://doi.org/10.1007/s40194-024-01696-7
SN - 0043-2288
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-59484
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Rethmeier, Michael
T1 - Challenges in dynamic heat source modeling in high-power laser beam welding
N2 - The amount of absorbed energy in the keyhole as well as its spatial and temporal distribution is essential to model the laser beam welding process. The recoil pressure, which develops because of the evaporation process induced by the absorbed laser energy at the keyhole wall, is a key determining factor for the macroscopic flow of the molten metal in the weld pool during high-power laser beam welding. Consequently, a realistic implementation of the effect of laser radiation on the weld metal is crucial to obtain reliable and accurate simulation results. In this paper, we discuss manyfold different improvements on the laser-material interaction, namely, the ray tracing method, in the numerical simulation of the laser beam welding process. The first improvement relates to locating the exact reflection points in the ray tracing method using a so-called cosine condition in the determination algorithm for the intersection of reflected rays and the keyhole surface. A second correction refers to the numerical treatment of the Gaussian distribution of the laser beam, whose beam width is defined by a decay of the laser intensity by a factor of 1/e2, thus ignoring around 14% of the total laser beam energy. In the third step, the changes in the laser radiation distribution in the vertical direction were adapted by using different approximations for the converging and the diverging regions of the laser beam, thus mimicking the beam caustic. Finally, a virtual mesh refinement was adopted in the ray tracing routine. The obtained numerical results were validated with experimental measurements.
KW - Laser beam welding
KW - Laser energy distribution
KW - Ray tracing
KW - Numerical modeling
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584748
DO - https://doi.org/10.2351/7.0001079
VL - 35
IS - 4
SP - 1
EP - 9
PB - Laser Institute of America
AN - OPUS4-58474
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naik, Aakash
A1 - Ueltzen, Katharina
A1 - Ertural, Christina
A1 - Jackson, Adam J.
A1 - George, Janine
T1 - LobsterPy: A package to automatically analyze LOBSTERruns
N2 - The LOBSTER (Deringer et al., 2011;Maintz et al., 2013 ,2016 ;Nelson et al., 2020 ) software aids in extracting quantum-chemical bonding information from materials by projecting the plane-wave based wave functions from density functional theory (DFT) onto an atomic orbital basis. LobsterEnv, a module implemented in pymatgen (Ong et al., 2013) by some of the authors of this package, facilitates the use of quantum-chemical bonding information obtained from LOBSTER calculations to identify neighbors and coordination environments. LobsterPy is a Python package that offers a set of convenient tools to further analyze and summarize the LobsterEnv outputs in the form of JSONs that are easy to interpret and process. These tools enable the estimation of (anti) bonding contributions, generation of textual descriptions, and visualization of LOBSTER computation results. Since its first release, both LobsterPy and LobsterEnv capabilities have been extended significantly. Unlike earlier versions, which could only automatically analyze Crystal Orbital Hamilton Populations (COHPs) (Dronskowski & Blöchl, 1993), both can now also analyze Crystal Orbital Overlap Populations (COOP) (Hughbanks & Hoffmann, 1983) and Crystal Orbital Bond Index (COBI) (Müller et al., 2021). Extracting the information about the most important orbitals contributing to the bonds is optional, and users can enable it as needed. Additionally, bonding-based features for machinelearning (ML) studies can be engineered via the sub-packages “featurize” and “structuregraphs”. Alongside its Python interface, it also provides an easy-to-use command line interface (CLI) that runs automatic analysis of the computations and generates a summary of results and publication-ready figures. LobsterPy has been used to produce the results in Ngo et al. (2023), Chen et al. (2024), Naik et al. (2023), and it is also part of Atomate2 (2023) bonding analysis workflow for generating bonding analysis data in a format compatible with the Materials Project (Jain et al., 2013) API.
KW - Materials Science
KW - Automation
KW - Bonding Analysis
KW - Materials Properties
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595809
DO - https://doi.org/10.21105/joss.06286
VL - 9
IS - 94
SP - 1
EP - 4
PB - The Open Journal
AN - OPUS4-59580
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosen, Andrew S.
A1 - Gallant, Max
A1 - George, Janine
A1 - Riebesell, Janosh
A1 - Sahasrabuddhe, Hrushikesh
A1 - Shen, Jimmy-Xuan
A1 - Wen, Mingjian
A1 - Evans, Matthew L.
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Rignanese, Gian-Marco
A1 - Persson, Kristin A.
A1 - Jain, Anubhav
A1 - Ganose, Alex M.
T1 - Jobflow: Computational Workflows Made Simple
N2 - We present Jobflow, a domain-agnostic Python package for writing computational workflows tailored for high-throughput computing applications. With its simple decorator-based approach, functions and class methods can be transformed into compute jobs that can be stitched together into complex workflows. Jobflow fully supports dynamic workflows where the full acyclic graph of compute jobs is not known until runtime, such as compute jobs that launch
other jobs based on the results of previous steps in the workflow. The results of all Jobflow compute jobs can be easily stored in a variety of filesystem- and cloud-based databases without the data storage process being part of the underlying workflow logic itself. Jobflow has been intentionally designed to be fully independent of the choice of workflow manager used to dispatch the calculations on remote computing resources. At the time of writing, Jobflow
workflows can be executed either locally or across distributed compute environments via an adapter to the FireWorks package, and Jobflow fully supports the integration of additional workflow execution adapters in the future.
KW - Automation
KW - Workflow
KW - Computational Materials Science
KW - Computations
KW - Software
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593104
DO - https://doi.org/10.21105/joss.05995
VL - 9
IS - 93
SP - 1
EP - 7
PB - The Open Journal
AN - OPUS4-59310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Vinzenz
A1 - Fasselt, Janek Maria
A1 - Kruse, Tobias
A1 - Klötzer, Christian
A1 - Kleba-Ehrhardt, Rafael
A1 - Choma, Tomasz
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Using ultrasonic atomization to recycle aluminium bronze chips for additive laser directed energy deposition
N2 - Abstract
In the post-processing of large maritime components, a considerable amount of waste in the form of milling and grinding chips is produced. At the same time, additive manufacturing technologies have shown great potential in producing high-volume parts for maritime applications, allowing novel design approaches and short lead times. In this context, this study presents a sustainable approach to recycle and use aluminium bronze waste material, generated during post-processing of large cast ship propellers, as feedstock for laser-powder directed energy deposition. The recycling technology used to produce powder batches is inductive re-melting in combination with ultrasonic atomization. The derived metal powders are characterized using digital image analysis, powder flowability tests, scanning electron microscopy as well as energy dispersive X-ray spectroscopy. Compared to conventional metal powders produced by gas atomization, the recycled material shows excellent sphericity and a powder size distribution with a higher content of finer and coarser particles. Metallographic sections of deposited additively produced specimens show an increased hardness and reduced ductility, but also competitive densities and higher yield and ultimate tensile strength compared to cast material. The process chain shows high potential for the maritime sector to enable circular and sustainable manufacturing.
KW - Industrial and Manufacturing Engineering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594444
DO - https://doi.org/10.1088/1757-899X/1296/1/012036
VL - 1296
IS - 1
SP - 1
EP - 11
PB - IOP Publishing
AN - OPUS4-59444
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, K.
A1 - Meschut, G.
A1 - Seitz, G.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - The Identification of a New Liquid Metal Embrittlement (LME) Type in Resistance Spot Welding of Advanced High Strength Steels on Reduced Flange Widths
N2 - Liquid metal embrittlement (LME) cracking is a phenomenon observed during resistance spot welding (RSW) of zinccoated advanced highstrength steels (AHSS) in automotive manufacturing. In this study, severe cracks are observed at the edge of the sheet under reduced flange widths. These cracks, traversing the AHSS sheet, culminate at the edge with a width of approximately 1.2 mm.
Through combined numerical and experimental investigations, and material testing, these cracks are identified and validated as a new type of LME crack. The mechanism behind this crack formation is attributed to unique geometric conditions that, when compared to center welding, amplify radial material flow by ninefold to 0.87 mm. The resultant tangential tensile stresses approximate 760 MPa, which exceed the yield strength of the examined advanced highstrength steel (AHSS) under heightened temperature conditions, and when combined with liquid zinc, promote the formation of this new type of LME crack.
KW - Liquid metal embrittlement
KW - Crack
KW - Advanced high strength steels
KW - Resistance spot welding
KW - Simulation
KW - Flange width
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586940
DO - https://doi.org/10.3390/met13101754
VL - 13
IS - 10
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-58694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Batatia, Ilyes
A1 - Benner, Philipp
A1 - Chiang, Yuan
A1 - Elena, Alin M.
A1 - Kovács, Dávid P.
A1 - Riebesell, Janosh
A1 - Advincula, Xavier R.
A1 - Asta, Mark
A1 - Avaylon, Matthew
A1 - Baldwin, William J.
A1 - Berger, Fabian
A1 - Bernstein, Noam
A1 - Bhowmik, Arghya
A1 - Bigi, Filippo
A1 - Blau, Samuel M.
A1 - Cărare, Vlad
A1 - Ceriotti, Michele
A1 - Chong, Sanggyu
A1 - Darby, James P.
A1 - De, Sandip
A1 - Della Pia, Flaviano
A1 - Deringer, Volker L.
A1 - Elijošius, Rokas
A1 - El-Machachi, Zakariya
A1 - Fako, Edvin
A1 - Falcioni, Fabio
A1 - Ferrari, Andrea C.
A1 - Gardner, John L. A.
A1 - Gawkowski, Mikołaj J.
A1 - Genreith-Schriever, Annalena
A1 - George, Janine
A1 - Goodall, Rhys E. A.
A1 - Grandel, Jonas
A1 - Grey, Clare P.
A1 - Grigorev, Petr
A1 - Han, Shuang
A1 - Handley, Will
A1 - Heenen, Hendrik H.
A1 - Hermansson, Kersti
A1 - Ho, Cheuk Hin
A1 - Hofmann, Stephan
A1 - Holm, Christian
A1 - Jaafar, Jad
A1 - Jakob, Konstantin S.
A1 - Jung, Hyunwook
A1 - Kapil, Venkat
A1 - Kaplan, Aaron D.
A1 - Karimitari, Nima
A1 - Naik, Aakash A.
A1 - Csányi, Gábor
T1 - A foundation model for atomistic materials chemistry
N2 - Atomistic simulations of matter, especially those that leverage first-principles (ab initio) electronic structure theory, provide a microscopic view of the world, underpinning much of our understanding of chemistry and materials science. Over the last decade or so, machine-learned force fields have transformed atomistic modeling by enabling simulations of ab initio quality over unprecedented time and length scales. However, early machine-learning (ML) force fields have largely been limited by (i) the substantial computational and human effort required to develop and validate potentials for each particular system of interest and (ii) a general lack of transferability from one chemical system to the next. Here, we show that it is possible to create a general-purpose atomistic ML model, trained on a public dataset of moderate size, that is capable of running stable molecular dynamics for a wide range of molecules and materials. We demonstrate the power of the MACE-MP-0 model—and its qualitative and at times quantitative accuracy—on a diverse set of problems in the physical sciences, including properties of solids, liquids, gases, chemical reactions, interfaces, and even the dynamics of a small protein. The model can be applied out of the box as a starting or “foundation” model for any atomistic system of interest and, when desired, can be fine-tuned on just a handful of application-specific data points to reach ab initio accuracy. Establishing that a stable force-field model can cover almost all materials changes atomistic modeling in a fundamental way: experienced users obtain reliable results much faster, and beginners face a lower barrier to entry. Foundation models thus represent a step toward democratizing the revolution in atomic-scale modeling that has been brought about by ML force fields.
KW - Materials Design
KW - Thermal Conducitivity
KW - Nanoparticles
KW - Batteries
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647829
DO - https://doi.org/10.1063/5.0297006
SN - 0021-9606
VL - 163
IS - 18
SP - 1
EP - 89
PB - AIP Publishing
AN - OPUS4-64782
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janssen, Jan
A1 - George, Janine
A1 - Geiger, Julian
A1 - Bercx, Marnik
A1 - Wang, Xing
A1 - Ertural, Christina
A1 - Schaarschmidt, Jörg
A1 - Ganose, Alexander Miguel
A1 - Pizzi, Giovanni
A1 - Hickel, Tilmann
A1 - Neugebauer, Jörg
T1 - A Python workflow definition for computational materials design
N2 - Numerous Workflow Management Systems (WfMS) have been developed in the field of computational materials science with different workflow formats, hindering interoperability and reproducibility of workflows in the field. To address this challenge, we introduce here the Python Workflow Definition (PWD) as a workflow exchange format to share workflows between Python-based WfMS, currently AiiDA, jobflow, and pyiron. This development is motivated by the similarity of these three Python-based WfMS, that represent the different workflow steps and data transferred between them as nodes and edges in a graph. With the PWD, we aim at fostering the interoperability and reproducibility between the different WfMS in the context of Findable, Accessible, Interoperable, Reusable (FAIR) workflows. To separate the scientific from the technical complexity, the PWD consists of three components: (1) a conda environment that specifies the software dependencies, (2) a Python module that contains the Python functions represented as nodes in the workflow graph, and (3) a workflow graph stored in the JavaScript Object Notation (JSON). The first version of the PWD supports directed acyclic graph (DAG)-based workflows. Thus, any DAG-based workflow defined in one of the three WfMS can be exported to the PWD and afterwards imported from the PWD to one of the other WfMS. After the import, the input parameters of the workflow can be adjusted and computing resources can be assigned to the workflow, before it is executed with the selected WfMS. This import from and export to the PWD is enabled by the PWD Python library that implements the PWD in AiiDA, jobflow, and pyiron.
KW - Worklows
KW - FAIR Workflows
KW - Automation
KW - Materials Acceleration Platforms
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643325
DO - https://doi.org/10.1039/D5DD00231A
SN - 2635-098X
SP - 1
EP - 14
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liu, Yuanbin
A1 - Morrow, Joe D.
A1 - Ertural, Christina
A1 - Fragapane, Natascia L.
A1 - Gardner, John L. A.
A1 - Naik, Aakash A.
A1 - Zhou, Yuxing
A1 - George, Janine
A1 - Deringer, Volker L.
T1 - An automated framework for exploring and learning potential-energy surfaces
N2 - Machine learning has become ubiquitous in materials modelling and now routinely enables large-scale atomistic simulations with quantum-mechanical accuracy. However, developing machine-learned interatomic potentials requires high-quality training data, and the manual generation and curation of such data can be a major bottleneck. Here, we introduce an automated framework for the exploration and fitting of potential-energy surfaces, implemented in an openly available software package that we call (‘automatic potential-landscape explorer’). We discuss design choices, particularly the interoperability with existing software architectures, and the ability for the end user to easily use the computational workflows provided. We show wide-ranging capability demonstrations: for the titanium–oxygen system, SiO2, crystalline and liquid water, as well as phase-change memory materials. More generally, our study illustrates how automation can speed up atomistic machine learning in computational materials science.
KW - Automation
KW - Machine Learning
KW - Machine learning potentials
KW - Amorphous materials
KW - High-throughput
KW - Ab initio
KW - Materials property prediction
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639882
DO - https://doi.org/10.1038/s41467-025-62510-6
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-63988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cope, Elana J.
A1 - Bustamante, Joana
A1 - Johnson, Zöe M.
A1 - Lancaster, Alicia
A1 - Gurunathan, Ramya
A1 - George, Janine
A1 - Agne, Matthias T.
T1 - Heat capacity estimation of complex materials for energy technologies
N2 - The control of heat in energy materials is one of the greatest current engineering challenges. Accurate estimations of heat capacity are key in creating and using materials safely and efficiently. Current models for heat capacity are often limited due to crude estimations of the phonon density of states, which is a key component of the thermodynamic definition of heat capacity. Utilization of a more detailed phonon density of states, which can easily be obtained from machine-learned algorithms, combined with dilation and electronic contributions, yields heat capacity estimations that are 29% better than the widely utilized Debye model and are comparable to state-of-the-art quantum mechanical calculations. The framework and necessary tools for heat capacity estimations demonstrated herein can be built into more detailed models and analyses, such as high-throughput characterization, transport models, or other thermodynamic assessments. Consequently, the so-called vibrational + dilation + electronic (VDE) model of heat capacity developed in this work better enables the informed design of next-generation devices.
KW - Materials Design
KW - Heat Capacity
KW - Machine learning potentials
KW - Thermal Management
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645711
DO - https://doi.org/10.1016/j.joule.2025.102054
SN - 2542-4351
VL - 9
IS - 8
SP - 1
EP - 12
PB - Elsevier Inc.
AN - OPUS4-64571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yalçınyüz, Aybike
A1 - Raute, Julius
A1 - Gonzalez-Gutierrez, Joamin
A1 - Pei, Eujin
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Electron Beam Bonding: A novel method for joining additively manufactured carbon fiber thermoplastic composites with aluminum to produce multi-material joints for lightweight applications
N2 - In recent years, new solutions have been explored to reduce the weight of components for the automotive, railway, and aerospace industries. For this reason, Carbon Fiber Composites (CFCs) have increasingly replaced metals in products that need to be lightweight. However, due to their poor thermal conductivity, CFCs have limited use in applications requiring efficient heat dissipation. In such applications, conventionally manufactured metal alloys are typically utilized. To address these limitations, a novel approach using a combination of additively manufactured aluminum and CFCs is proposed to exploit the distinct advantages of both materials. These innovative hybrid structures aim to combine good structural and thermal management properties with reduced weight compared to conventionally produced metal products. In this study, additively manufactured aluminum alloy (AlSi10Mg) and short carbon fiber Polyamide 6 composite (sCF-PA6) are utilized to produce metal–polymer pairs using electron beam energy to bond the two materials. Direct irradiation of short CFCs with electron beam leads to polymer degradation. Thus, a novel method “Electron Beam Bonding” for joining CFCs with aluminum alloy in various joint configurations using electron beam technology is demonstrated. This innovative approach presents a promising solution for creating metal–polymer multi-materials for lightweight applications.
KW - Electron beam bonding
KW - Multi-material
KW - Lightweight
KW - Additive manufactured materials
KW - Short carbon fiber composites
KW - AlSi10Mg
KW - Joining
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641705
DO - https://doi.org/10.1007/s40964-025-01206-1
SN - 2363-9512
SP - 1
EP - 7
PB - Springer International Publishing
CY - Cham
AN - OPUS4-64170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Klotz, Ulrich E.
A1 - Tiberto, Dario
A1 - Vafaeenezhad, Hossein
A1 - Mishurova, Tatiana
A1 - Skrotzki, Birgit
T1 - Effect of keyhole and lack-of-fusion pores on the anisotropic microstructure and mechanical properties of PBF-LB/M-produced CuCrZr alloy
N2 - Due to the high reflectance and heat conductivity of copper and its alloys, the processing window for laser-based powder bed fusion (PBF-LB/M) processing of high-density copper components fundamentally overlaps with conduction and keyhole melting zones, resulting in the emergence of certain pores in the structure of printed parts. The present research aims to study how the development of process-induced lack-of-fusion or keyhole porosities during the PBF-LB/M process can affect the anisotropic microstructure and mechanical properties of the produced copper alloys. For this purpose, several samples were produced utilizing a similar CuCrZr-feedstock composition but varied process parameters from different areas of the PBF-LB/M processing window, specifically at laser powers of 300 W and 380 W which define the boarders of the conduction and keyhole regimes. X-ray computed tomography (XCT) revealed that the 300-W and 380-W samples achieved relative densities of 98.88% and 99.99%, respectively, with elongated lack-of-fusion pores forming at 300 W and semi-spherical keyhole pores at 380 W. Microstructural analyses employing scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD) demonstrated strong anisotropy in different build directions of the samples, owing to the growth of long columnar grains with intense < 101 orientation along the build directions. Here, the emergence of different types of pores can cause competition between the epitaxial growth of columnar grains and the heterogeneous nucleation of new grains on the layers’ interfaces, thereby significantly varying the grain size, preferred orientation, crystallographic texture, and microstructural anisotropy of the samples. Furthermore, compression tests and nanoindentation measurements of the printed alloys in the longitudinal and transverse directions revealed that the 300 W and 380 W samples exhibited compressive strength anisotropies of 0.061 and 0.072, and average nanoindentation hardness values of 1.3 GPa and 1.5 GPa, respectively. The orientation of elongated lack-of-fusion porosities perpendicular to the loading axis was identified as the most damaging factor, significantly reducing mechanical performance compared to the uniformly distributed keyhole pores.
KW - Copper Alloy
KW - Laser-based powder bed fusion
KW - Microstructure
KW - Mechanical properties
KW - X-ray computed tomography (XCT)
KW - Porosity
KW - Anisotropy
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625655
DO - https://doi.org/10.1007/s40964-025-00972-2
SN - 2363-9520
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-62565
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis
A1 - Shakeel, Y.
A1 - Gedsun, A.
A1 - Forti, M.
A1 - Hunke, S.
A1 - Han, Ying
A1 - Hammerschmidt, T.
A1 - Aversa, R.
A1 - Olbricht, Jürgen
A1 - Chmielowski, M.
A1 - Stotzka, R.
A1 - Bitzek, E.
A1 - Hickel, Tilmann
A1 - Skrotzki, Birgit
T1 - Management of reference data in materials science and engineering exemplified for creep data of a single-crystalline Ni-based superalloy
N2 - The identification of process-structure-property relationships of materials inevitably requires the combination of research data from different measurements. Therefore, the concepts related to FAIR (findable, accessible, interoperable, reusable) data handling, increasingly reported in literature, are particularly important in the materials science and engineering domain. However, they have not yet been integrated into a single, overarching methodological framework, particularly for reference data. Here, we introduce such a framework. Our concept covers data generation, documentation, handling, storage, sharing, data search and discovery, retrieval, and usage. Furthermore, we prototypically implement it using a real dataset with creep data of a single-crystal CMSX-6 Ni-based superalloy. The presented implementation is traceable and permanently accessible through open repositories. The individual elements considered in the framework ensure the functionality and usability of the data and, thus, the adherence to the FAIR principles. In conjunction with this, we present a definition for reference data of materials. Our definition underlines particularly the importance of a comprehensive documentation, e.g., on material provenance, data processing procedures, and the software and hardware used, including software-specific input parameters, as these details enable data users or independent parties to assess the quality of the datasets and to reuse and reproduce the results. Reference data that is managed according to the proposed framework can be used to advance knowledge in the materials science and engineering domain, e.g., by identifying new process-structure-property relations.
KW - Referenzdaten
KW - NFDI-MatWerk
KW - Data schema
KW - Research Data Management
KW - Reference Data
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625047
DO - https://doi.org/10.1016/j.actamat.2025.120735
VL - 286
SP - 1
EP - 15
PB - Elsevier Inc.
AN - OPUS4-62504
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smales, Glen Jacob
A1 - Anker, A. S.
A1 - Annadurai, V.
A1 - Balazs, D. M.
A1 - Bienert, Ralf
A1 - Bouwman, W. G.
A1 - Breßler, Ingo
A1 - Breternitz, J.
A1 - Brok, E. S.
A1 - Bryant, G.
A1 - Clulow, A. J.
A1 - Crater, E. R.
A1 - De Geuser, F.
A1 - Del Giudice, A.
A1 - Deumer, J.
A1 - Disch, S.
A1 - Dutt, S.
A1 - Frank, K.
A1 - Fratini, E.
A1 - Garcia, P. R. A. F.
A1 - Gilbert, E. P.
A1 - Hahn, Marc Benjamin
A1 - Hallett, J.
A1 - Hohenschutz, M.
A1 - Hollamby, M.
A1 - Huband, S.
A1 - Ilavsky, J.
A1 - Jochum, J. K.
A1 - Juelsholt, M.
A1 - Mansel, B. W.
A1 - Penttilä, P.
A1 - Pittkowski, R. K.
A1 - Portale, G.
A1 - Pozzo, L. D.
A1 - Rochels, L.
A1 - Rosalie, Julian
A1 - Saloga, Patrick E. J.
A1 - Seibt, S.
A1 - Smith, A. J.
A1 - Smith, G. N.
A1 - Spiering, G. A.
A1 - Stawski, Tomasz M.
A1 - Taché, O.
A1 - Thünemann, Andreas
A1 - Toth, K.
A1 - Whitten, A. E.
A1 - Wuttke, J.
T1 - The human factor - Results of a small-angle scattering data analysis round robin
N2 - A round-robin study has been carried out to estimate the impact of the human element in small-angle scattering data analysis. Four corrected datasets were provided to participants ready for analysis. All datasets were measured on samples containing spherical scatterers, with two datasets in dilute dispersions and two from powders. Most of the 46 participants correctly identified the number of populations in the dilute dispersions, with half of the population mean entries within 1.5% and half of the population width entries within 40%. Due to the added complexity of the structure factor, far fewer people submitted answers on the powder datasets. For those that did, half of the entries for the means and widths were within 44 and 86%, respectively. This round-robin experiment highlights several causes for the discrepancies, for which solutions are proposed.
KW - Round Robin
KW - Data analysis
KW - Small-angle scattering
KW - Nanomaterials
KW - Interlaboratory comparability
KW - Nanostructure quantification
KW - Methodology
KW - MOUSE
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587091
DO - https://doi.org/10.1107/S1600576723008324
SN - 1600-5767
VL - 56
IS - 6
SP - 1618
EP - 1629
PB - Wiley-Blackwell
CY - Oxford
AN - OPUS4-58709
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosalie, Julian
A1 - Hohenwarter, A.
T1 - Dynamic Precipitation during High-Pressure Torsion of a Magnesium–Manganese Alloy
N2 - An ultrafine-grained magnesium alloy has been produced through room temperature high-pressure torsion (HPT) of solutionized Mg–1.35 wt% Mn. Dynamic precipitation of nanometer-scale Mn particles occurs during deformation. These particles populate the grain boundaries, acting as pinning sites which allow the alloy to develop a grain size of 140 nm after 0.5 rotations. Further, HPT deformation results in a gradual increase in grain size with no increase in precipitate size. Despite the extensive deformation applied, the alloy does not develop a bimodal grain structure and retains a grain size of 230 nm after 10 complete rotations, demonstrating the stability and effectiveness of these pinning particles.
KW - Grain-boundary pinning
KW - Magnesium alloys
KW - High-pressure torsion
KW - Severe plastic deformation
KW - Ultrafine-grained materials
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656471
DO - https://doi.org/10.1002/adem.202500424
SN - 1527-2648
VL - 28
IS - 4
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-65647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jauregui Rozo, Maria
A1 - Sunder, S.
A1 - Tabaka, Weronika
A1 - Klaffke, Benjamin
A1 - Ruckdäschel, H.
A1 - Schartel, Bernhard
T1 - Unveiling aluminum diethyl phosphinate dual identity: Transfer from epoxy resins to glass fiber-reinforced composites
N2 - This study examines the transfer of the flame-retardant aluminum diethyl phosphinate (AlPi) from epoxy resins to composites and the impact of AlPi on fire behavior and fire stability. Further, the effects of different particle sizes and the addition of zinc hydroxy stannate (ZHS) and inorganic silicate (InSi) are investigated. The research provides a detailed analysis of the fire behavior, fire stability, pyrolysis, flame-retardant modes of action, and flame retardancy index. Interestingly, the particle sizes did not significantly affect the flammability, fire behavior, or fire stability in the systems investigated. AlPi acts primarily in the gas phase, releasing phosphorus that yields flame inhibition. Adding glass fibers (GFs) to the epoxy resin boosts the flame retardancy in the condensed phase, reducing the heat release rate (HRR), total heat release (THR), and peak heat release rate (PHRR) by about 60%. This improvement is largely due to replacing fuel and forming a protective layer during burning. Despite the differences between thermoset and composite, the study demonstrates an effective transfer of flame-retardant properties from epoxy resins to fiber-reinforced composites, significantly enhancing the flame retardancy performance in both material systems.
KW - Aluminum diethyl phosphinate
KW - Epoxy resins
KW - Fire behavior
KW - Fire stability
KW - Gas-phase active
KW - Glass fiber-reinforced composites
KW - Particle sizes
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643013
DO - https://doi.org/10.1002/pc.29911
SN - 1548-0569
SN - 0272-8397
VL - 46
IS - 14
SP - 12981
EP - 12999
PB - Wiley
AN - OPUS4-64301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Bär, J.
A1 - Kanna, N.K.
A1 - Duarte, Larissa
A1 - Madia, Mauro
T1 - Determination of the Kitagawa-Takahashi Diagram using DC Potential Drop Measurements
N2 - The Kitagawa-Takahashi Diagram is an important tool for describing the fatigue limit of components containing defects. The models used for its description differ, particularly in the transition region corresponding to the short crack regime. Therefore, for a reliable statement about the fatigue limit in this area, an experimental validation of the models is necessary. However, the standardized staircase method requires a large number of samples and has a long test duration. In this work, a method is presented that allows a simpler and faster validation of the Kitagawa-Takahashi Diagram in the region of short cracks. Rectangular notches with a defined width and depth were manufactured in flat samples of a low-alloyed steel with two different heat treatments using an engraving laser. This method allows a rapid production of very sharp notches without plastic deformation and with only a slight thermal influence on the surrounding material. The samples prepared in this way were fatigued with block wise increasing loads until failure. Cracks are detected by means of a Direct Current Potential Drop method. The length of the loading block (number of cycles) is determined by the measured potential drop. This procedure enables a reliable and precise determination of the limit stress for the respective notch size with low experimental effort and time consumption. The tests have
shown that in case of the normalized steel none of the models describes the determined values for the fatigue limit. For the hardened steel, the plot of the fatigue limit as a function of the Murakami parameter √area in combination with the El Haddad model allows a satisfactory description of the measured values.
T2 - 5th International Symposium on Fatigue Design and Material Defects
CY - Trento, Italy
DA - 14.05.2025
KW - Kitagawa-Takahashi diagram
KW - Damage tolerance
KW - Fatigue
KW - Potential drop
KW - Fracture mechanics
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655519
DO - https://doi.org/10.1016/j.prostr.2025.12.283
VL - 76
SP - 27
EP - 34
PB - Elsevier B.V.
AN - OPUS4-65551
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, Sergej
A1 - Biegler, Max
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Integration of hybrid laser-arc and narrow gap submerged arc welding for cost-effective joining of 80 mm thick S355ML steel plates
N2 - This paper presents the results of developing a cost-effective, robust process for welding thick steel plates. Welding trials were performed on S355ML structural steel plates with a thickness of 80 mm. A specially designed U-shaped joint preparation with a 45 mm root face was proposed to enable thick welds to be welded using a combined technique. In the developed process, a hybrid laser arc weld (HLAW) is performed as the first pass. Subsequently, narrow-gap submerged arc welding (NG-SAW) is applied to the opposite side using a multi-layer technique. The weld cross-section is completed using a reliable overlap of both the HLAW and NG-SAW welds. This method achieves a 2.9-fold reduction in weld volume and filler material consumption, as well as shorter production times for thick-walled welds. Further advantages of the process combination include eliminating the need to form the root of the HLAW weld and the absence of a backing support. The applied process parameters ensure that the maximum heat input does not exceed 5 kJ/mm, leading to uniform hardness across the weld metal and heat-affected zone (HAZ). Impact toughness testing at −40 °C demonstrated excellent performance, with Charpy V-notch energies of 138 ± 45 J in the arc-dominated region and 65 ± 12 J in the critical laser-dominated zone of the HLAW weld. In addition, the NG-SAW weld exhibited an average Charpy V-notch energy of 274 ± 5 J, confirming excellent low-temperature toughness of the fill passes. Owing to its high process stability and practical applicability, the proposed welding approach shows high potential for integration into the fabrication of thick-walled offshore constructions.
KW - Hybrid laser arc welding
KW - Narrow gap submerged arc welding
KW - Low carbon structural steel
KW - Fusion zone size
KW - Microstructure
KW - Impact absorbed energy
KW - Hardness
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655627
DO - https://doi.org/10.1016/j.optlastec.2026.114796
SN - 0030-3992
VL - 197
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-65562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, M.
A1 - Wang, J.
A1 - Kaiser, L.
A1 - Rethmeier, Michael
T1 - Automated Tool-Path Generation for Rapid Manufacturing of Additive Manufacturing Directed Energy Deposition Geometries
N2 - In additive manufacturing (AM) directed energy deposition (DED), parts are built by welding layers of powder or wire feedstock onto a substrate with applications for steel powders in the fields of forging tools, spare parts, and structural components for various industries. For large and bulky parts, the choice of toolpaths influences the build rate, the mechanical performance, and the distortions in a highly geometry-dependent manner. With weld-path lengths in the range of hundreds of meters, a reliable, automated tool-path generation is essential for the usability of DED processes. This contribution presents automated tool-path generation approaches and discusses the results for arbitrary geometries. Socalled “zig-zag” and “contour-parallel” processing strategies are investigated and the tool-paths are automatically formatted into machine-readable g-code for experimental validation to build sample geometries. The results are discussed in regard to volume-fill, microstructure, and porosity in dependence of the path planning according to photographs and metallographic cross-sections.
KW - Porosity
KW - Path planning
KW - Mechanical properties
KW - Laser metal deposition
KW - Additive manufacturing
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510454
DO - https://doi.org/10.1002/srin.202000017
VL - 91
IS - 11
SP - 2000017
PB - WILEY-VCH Verlag GmbH & co. KGaA
CY - Weinheim
AN - OPUS4-51045
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, Sergej
A1 - El-Batahgy, Abdel-Monem
A1 - Gumenyuk, Andrey
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Application of Hybrid Laser Arc Welding for Construction of LNG Tanks Made of Thick Cryogenic 9% Ni Steel Plates
N2 - Hybrid laser-arc welding (HLAW) was applied for butt welding of 14.5 mm thick plates of ferritic cryogenic steel X8Ni9 containing 9% Ni, which is used for manufacturing storage and transport facilities of liquefied natural gas (LNG). The weld seam formation and the achievable metallurgical and mechanical properties of the hybrid welds were investigated experimentally for two types of filler wire, an austenitic wire dissimilar to the base metal (BM) and an experimentally produced matching ferritic wire. Safe penetration and uniform distribution of the austenitic filler metal in the narrow hybrid weld could only be achieved in the upper, arcdominated part of the weld. The pronounced heterogeneous distribution of the austenitic filler metal in the middle part and in the root area of the weld could not ensure sufficient notched impact toughness of the weld metal (WM). As a result, a decrease in the impact energy down to 17±3 J was observed, which is below the acceptance level of ≥34 J for cryogenic applications. In contrast, the use of a matching ferritic filler wire resulted in satisfactory impact energy of the hybrid welds of up to 134±52 J at the concerned cryogenic temperature of -196 °C. The obtained results contribute to an important and remarkable conversion in automated manufacturing of LNG facilities. In other words, the results will help to develop a new laser-based welding technology, where both quality and productivity are considered.The efficiency of the developed welding process has been demonstrated by manufacturing a prototype where a segment of the inner wall of large size LNG storage tank was constructed. In this concern, hybrid laser arc welding was conducted in both horizontal (2G) and vertical (3G) positions as a simulation to the actual onsite manufacturing. The prototype was fabricated twice where its quality was confirmed based on non-destructive and destructive examinations.
KW - Hardness
KW - Hybrid Laser arc Welding
KW - 9% Ni Steel
KW - Fusion zone size
KW - Microstructure
KW - Tensile Strength
KW - Impact Absorbed Energy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586080
DO - https://doi.org/10.1007/s40516-023-00229-2
SP - 1
EP - 22
PB - Springer Nature
AN - OPUS4-58608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fu, B.
A1 - Shen, J.
A1 - Suhuddin, U.
A1 - Pereira, A.
A1 - Maawad, E.
A1 - dos Santos, J.
A1 - Klusemann, B.
A1 - Rethmeier, Michael
T1 - Revealing joining mechanism in refill friction stir spot welding of AZ31 magnesium alloy to galvanized DP600 steel
N2 - The application of magnesium (Mg) inevitably involves dissimilar welding with steel. A novel solid state spot welding method, refill friction stir spot welding (refill FSSW), was utilized to weld AZ31 Mg alloy to galvanized DP600 steel. Although Mg/Fe is an immiscible alloy system, defect-free welds with high strength were successfully obtained in a wide parameter window. The results of microstructure, interfacial reactions, and mechanical properties are reported to reveal the underlying joining mechanism. Due to the melting of Zn coating and subsequent Mg-Zn reactions, Mg-Zn eutectic and intermetallic compounds were detected within welds. Heterogeneous interfacial reactions occur along Mg/steel interface, and the relationship between interfacial structure and fracture behavior was investigated. The joining mechanism is associated with Zn coating and Fe-Al layer: 1) the presence of Zn coating is beneficial for achieving high-quality welding between Mg and steel, it protects the interface from oxidation and contributes to brazing of the weld; 2) the Al present in Mg alloy reacts with Fe, resulting in the growth of Fe-Al layer, which contributes to the diffusion bonding in the interface. The overall results clearly show that Refill FSSW is a competitive welding method for joining Mg and galvanized steel.
KW - Refill friction stir spot welding
KW - Multi-materials joining
KW - Magnesium alloy
KW - Galvanized steel
KW - Mechanical properties
KW - Microstructure
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536878
DO - https://doi.org/10.1016/j.matdes.2021.109997
SN - 0264-1275
VL - 209
SP - 109997
PB - Elsevier Ltd.
AN - OPUS4-53687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Churiaque, C.
A1 - Sanchez-Amaya, J.M.
A1 - Üstündag, Ömer
A1 - Porrua-Lara, M.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Improvements of hybrid laser arc welding for shipbuilding T-joints with 2F position of 8 mm thick steel
N2 - the joints throughout the structure. The flat units are constituted by butt welded flat plates, on which longitudinal T-welded reinforcements are placed to rigidize the structure. Among the different welding technologies, Hybrid Laser Arc Welding (HLAW) is becoming a mature process, profitable and highly productive. In addition, more innovative welding equipment are being developed nowadays, offering greater work flexibility, and raising expectations of achieving better quality, and economic viability. Another key point of HLAW to keep in mind is that structural distortions are reduced, resulting in decreasing the cost and time of straightening work.
In the present contribution, the influence of HLAW parameters on the quality of fillet joints of naval steel has been analysed. Experimental HLAW tests were performed with a high power disk laser to join EH36 naval steel plates, with a T configuration. The influence of different processing parameters has been analysed, as the laser power, welding speed, wire feed rate and the configuration of the HLAW processes (including head angle and laser/arc leading process). In addition, FEM simulations were carried out in order to estimate residual stresses and distortion of welded part. The distortion values provided by FEM presented excellent agreement with the measured experimental results. To evaluate the welds, non destructive tests including X-ray tests, metallographic analysis of cross sections, and microhardness mapping tests were performed.
Full penetration 8 mm T welds were obtained for the first time at an industrially applicable 2F position with a reasonable HLAW head angle, in one single step without sealing root, and using zero gap square groove Edge preparation. The present contribution presents welding rates up to 2.2 m/min for 2F T-joints of this steel thickness, a much higher processing velocity than previously reported for industrial applications.
KW - Hybrid laser arc welding
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528410
DO - https://doi.org/10.1016/j.optlastec.2021.107284
VL - 143
SP - 1
EP - 20
PB - Elsevier Ltd.
AN - OPUS4-52841
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical analysis of the partial penetration high power laser beam welding of thick sheets at high process speeds
N2 - The present work is devoted to the numerical analysis of the high-power laser beam welding of thick sheets at different welding speeds. A three-dimensional transient multi-physics numerical model is developed, allowing for the prediction of the keyhole geometry and the final penetration depth. Two ray tracing algorithms are implemented and compared, namely a standard ray tracing approach and an approach using a virtual mesh refinement for a more accurate calculation of the reflection points. Both algorithms are found to provide sufficient accuracy for the prediction of the keyhole depth during laser beam welding with process speeds of up to 1.5 m/min. However, with the standard algorithm, the penetration depth is underestimated by the model for a process speed of 2.5 m/min due to a trapping effect of the laser energy in the top region. In contrast, the virtually refined ray tracing approach results in high accuracy results for process speeds of both 1.5 m/min and 2.5 m/min. A detailed study on the trapping effect is provided, accompanied by a benchmark including a predefined keyhole geometry with typical characteristics for the high-power laser beam welding of thick plates at high process speed, such as deep keyhole, inclined front keyhole wall, and a hump.
KW - High-power laser beam welding
KW - High process speeds
KW - Deep penetration
KW - Numerical modeling
KW - Ray tracing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532170
DO - https://doi.org/10.3390/met11081319
SN - 2075-4701
VL - 11
IS - 8
SP - 1
EP - 16
PB - MDPI
CY - Basel
AN - OPUS4-53217
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fu, B.
A1 - Shen, J.
A1 - Suhuddin, U.
A1 - Chen, T.
A1 - dos Santos, J.
A1 - Klusemann, B.
A1 - Rethmeier, Michael
T1 - Improved mechanical properties of cast Mg alloy welds via texture weakening by differential rotation refill friction stir spot welding
N2 - Cast magnesium alloys welds produced by refill friction stir spot welding (refill FSSW) show low lap shear strength (LSS) and constantly fail in stirred zone (SZ) shear mode. The cause is most probably related to the heavily textured microstructure. Here, to re-engineer the resulting microstructure, we pro- pose a novel process variant, the differential rotation refill FSSW (DR-refill FSSW). DR-refill FSSW stim- ulates discontinuous dynamic recrystallization and produces a bimodal microstructure with weakened texture. Therefore, the deformation incompatibility between SZ and thermal-mechanically affected zone is avoided. The welds have 50% higher LSS than that of standard refill FSSW welds, and fail in a different failure mode, i.e., SZ pull-out mode. DR-refill FSSW provides a new and effective strategy for improving the performance of spot welds based on microstructural engineering.
KW - Refill friction stir spot welding
KW - Magnesium Alloy
KW - Texture
KW - EBSD
KW - Plastic deformation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536885
DO - https://doi.org/10.1016/j.scriptamat.2021.114113
SN - 1359-6462
VL - 203
SP - 114113
PB - Elsevier Ltd.
AN - OPUS4-53688
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Winterkorn, René
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Wire arc additive manufacturing with novel Al-Mg-Si filler wire - Assessment of weld quality and mechanical properties
N2 - Wire arc additive manufacturing enables the production of near-net shape large-volume metallic components leveraging an established industrial base of welding and cladding technology and adapting it for layer-wise material deposition. However, the complex relationship between the process parameters and resulting mechanical properties of the components still remains challenging. In case of high-strength Al-Mg-Si aluminum alloys, no commercial filler wires are yet available due the high susceptibility of solidification cracking as well as the necessary efforts to obtain acceptable mechanical properties. To address this need, we evaluated a novel filler wire based on AlMg0.7Si doped with a Ti5B1 master alloy to foster fine equiaxed grains within the deposited metal. The correlation between the process parameters and component quality was examined by analyzing the size and distribution of pores as well as the grain morphology. Furthermore, we evaluated the influence of different post-weld heat treatment strategies to achieve mechanical properties corresponding to the reference wrought material. We demonstrated that fine equiaxed grains in the weld metal reduced the susceptibility of solidification cracking significantly. The novel AlMg0.7Si-TiB (S Al 6063-TiB) filler wire facilitated wire arc additive manufacturing of high-strength aluminum components with mechanical properties that were almost as superior as the corresponding wrought base material.
KW - Wire arc additive manufacturing
KW - Precipitation hardening aluminum alloys
KW - AlMg0.7SiTiB filler wire
KW - Grain refinement
KW - Mechanical properties
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538327
DO - https://doi.org/10.3390/met11081243
SN - 2075-4701
VL - 11
IS - 8
SP - 1
EP - 13
PB - MDPI
CY - Basel
AN - OPUS4-53832
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Elucidation of the Bulging Effect by an Improved Ray-Tracing Algorithm in Deep Penetration Wire Feed Laser Beam Welding and its Influence on the Mixing Behavior
N2 - Herein, an improved ray-tracing routine using a virtual mesh refinement approach is adopted in a 3D transientmultiphysics computational fluid Dynamics model for deep penetration wire feed laser beam welding. In a previous study, it was shown that the improved localization of the reflection points of the subrays within the keyhole leads to a more realistic development of the keyhole Depth being validated with experimental results. Another effect investigated in Detail herein is a drastic change in the flow behavior in the weld pool, which promotes the occurrence of a necking area in the solidification line and subsequent bulging under specific circumstances. This has a detrimental effect on the filler material element transport in the weld pool, leading to an inhomogeneous dilution of the added material. The numerical observations are backed up by experimentally obtained data, allowing to provide a clear physics-based explanation of the reduced mixing behavior of the filler wire in the melt pool.
KW - Bulging effects
KW - Numerical welding simulations
KW - Ray-tracing methods
KW - Wire feed laser beam welding
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-543322
DO - https://doi.org/10.1002/adem.202101299
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-54332
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bakir, Nasim
A1 - Üstündag, Ömer
A1 - Bachmann, Marcel
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - The bulging effect and its relevance in high power laser beam welding
N2 - The present work deals with the recently confirmed widening of the weld pool interface, known as a bulging effect, and its relevance in high power laser beam welding. A combined experimental and numerical approach is utilized to study the influence of the bulge on the hot cracking formation and the transport of alloying elements in the molten pool. A technique using a quartz glass, a direct-diode laser illumination, a high-speed camera, and an infrared camera is applied to visualize the weld pool geometry in the longitudinal section. The study examines the relevance of the bulging effect on both, partial and complete penetration, as well as for different sheet thicknesses ranging from 8 mm to 25 mm. The numerical analysis shows that the formation of a bulge region is highly dependent on the penetration depth and occurs more frequently during partial penetration above 6 mm and complete penetration above 8 mm penetration depth, respectively. The location of the bulge correlates strongly with the cracking location. The obtained experimental and numerical results reveal that the bulging effect increases the hot cracking susceptibility and limits the transfer of alloying elements from the top of the weld pool to the weld root.
T2 - 18th Nordic Laser Materials Processing Conference (18th NOLAMP)
KW - High-power laser beam welding
KW - Bulge effect
KW - Solidification cracking
KW - Multi-physical modelling
KW - Metal mixing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539149
DO - https://doi.org/10.1088/1757-899X/1135/1/012003
VL - 1135
IS - 012003
SP - 1
EP - 11
PB - IOP Publishing
AN - OPUS4-53914
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Investigation of the gap bridgeability at high-power laser hybrid welding of plasma-cut thick mild steels with AC magnetic support
N2 - One of the challenges of the high-power hybrid laser welding of thick steels is the sensitivity of the process of the process to manufacturing tolerances. This usually leads to a time-consuming preparation of the welding edges, such as milling. The study deals with the influence of the edge quality of milled and plasma-cut steel made of S355J2 with a wall thickness of 20 mm on the laser hybrid welded seam quality. Furthermore, the gap bridgeability and the tolerances towards edge misalignment was investigated. An AC magnet was used as backing support to prevent sagging and positioned under the workpiece, to generate an upwards directed electromagnetic pressure. The profiles of the edges and the gap on the top and root side were measured using a digital camera. Single-pass laser hybrid welds of plasma-cut edges could be welded using a laser beam power of just 13.7 kW. A gap bridgeability up to 2 mm and misalignment of edges up to 2 mm could be achieved successful. Additionally, the independence of the cutting side and the welding side was shown, so that samples were welded to the opposite side to their cutting. For evaluation of internal defects or irregularities, X-ray images were carried out. Charpy impact strength tests were performed to determine the toughness of the welds.
T2 - X International Conference «Beam Technologies & Laser Application»
KW - Laser hybrid welding
KW - Magnetic bath support
KW - Plasma-cut samples
KW - Thick plate welding
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539248
DO - https://doi.org/10.1088/1742-6596/2077/1/012007
VL - 2077
IS - 012007
SP - 1
EP - 8
PB - IOP Publishing
AN - OPUS4-53924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Russo, Francesco F.
A1 - Nowatzky, Yannek
A1 - Jaeger, Carsten
A1 - Parr, Maria K.
A1 - Benner, Philipp
A1 - Muth, Thilo
A1 - Lisec, Jan
T1 - Machine learning methods for compound annotation in non‐targeted mass spectrometry—A brief overview of fingerprinting, in silico fragmentation and de novo methods
N2 - Non‐targeted screenings (NTS) are essential tools in different fields, such as forensics, health and environmental sciences. NTSs often employ mass spectrometry (MS) methods due to their high throughput and sensitivity in comparison to, for example, nuclear magnetic resonance–based methods. As the identification of mass spectral signals, called annotation, is labour intensive, it has been used for developing supporting tools based on machine learning (ML). However, both the diversity of mass spectral signals and the sheer quantity of different ML tools developed for compound annotation present a challenge for researchers in maintaining a comprehensive overview of the field.In this work, we illustrate which ML‐based methods are available for compound annotation in non‐targeted MS experiments and provide a nuanced comparison of the ML models used in MS data analysis, unravelling their unique features and performance metrics. Through this overview we support researchers to judiciously apply these tools in their daily research. This review also offers a detailed exploration of methods and datasets to show gaps in current methods, and promising target areas, offering a starting point for developers intending to improve existing methodologies.
KW - Mass Spectrometry
KW - Spectra annotation
KW - Machine learning
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608732
DO - https://doi.org/10.1002/rcm.9876
VL - 38
IS - 20
SP - 1
EP - 15
PB - Wiley
AN - OPUS4-60873
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghata, Anupama
A1 - Bernges, Tim
A1 - Maus, Oliver
A1 - Wankmiller, Björn
A1 - Naik, Aakash
A1 - Bustamante, Joana
A1 - Gaultois, Michael W.
A1 - Delaire, Olivier
A1 - Hansen, Michael Ryan
A1 - George, Janine
A1 - Zeier, Wolfgang G.
T1 - Exploring the Thermal and Ionic Transport of Cu+ Conducting Argyrodite Cu7PSe6
N2 - AbstractUnderstanding the origin of low thermal conductivities in ionic conductors is essential for improving their thermoelectric efficiency, although accompanying high ionic conduction may present challenges for maintaining thermoelectric device integrity. This study investigates the thermal and ionic transport in Cu7PSe6, aiming to elucidate their fundamental origins and correlation with the structural and dynamic properties. Through a comprehensive approach including various characterization techniques and computational analyses, it is demonstrated that the low thermal conductivity in Cu7PSe6 arises from structural complexity, variations in bond strengths, and high lattice anharmonicity, leading to pronounced diffuson transport of heat and fast ionic conduction. It is found that upon increasing the temperature, the ionic conductivity increases significantly in Cu7PSe6, whereas the thermal conductivity remains nearly constant, revealing no direct correlation between ionic and thermal transport. This absence of direct influence suggests innovative design strategies in thermoelectric applications to enhance stability by diminishing ionic conduction, while maintaining low thermal conductivity, thereby linking the domains of solid‐state ionics and thermoelectrics. Thus, this study attempts to clarify the fundamental principles governing thermal and ionic transport in Cu+‐superionic conductors, similar to recent findings in Ag+ argyrodites.
KW - Thermoelectrics
KW - Phonons
KW - Chemically Complex Materials
KW - DFT
KW - Bonding Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608866
DO - https://doi.org/10.1002/aenm.202402039
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-60886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Albakri, Bashar
A1 - Turski Silva Diniz, Analice
A1 - Benner, Philipp
A1 - Muth, Thilo
A1 - Nakajima, Shinichi
A1 - Favaro, Marco
A1 - Kister, Alexander
ED - Hillman, Robert
T1 - Machine learning-assisted equivalent circuit identification for dielectric spectroscopy of polymers
N2 - Polymers have become indispensable across fields of application, and understanding their structure–property relationships and dynamic behaviour is essential for performance optimization. Polymer membranes, particularly ion exchange membranes, play a crucial role in renewable energy conversion technologies, fuel cells, solar energy conversion, and energy storage. In this context, broadband dielectric spectroscopy (BDS) offers a powerful, non-destructive approach to investigate the electrical response and relaxation dynamics of polymers. These properties are investigated by parametrizing the system’s impedance response in terms of a network of circuit elements, i.e. the electrical equivalent circuit (EEC), whose impedance resembles the one of the system under investigation. However, the determination of the EEC from BDS data is challenging due to system complexity, interdependencies of circuit elements, and researcher biases. In this work, we propose a novel approach that incorporates a convolutional neural network (CNN) model to predict the EEC topology. By reducing user bias and enhancing data analysis, this approach aims to make BDS accessible to both experienced users and those with limited expertise. We show that the combination of machine learning and BDS provides valuable insights into the dynamic behaviour of polymer membranes, thus facilitating the design and characterization of tailored polymers for various applications. We also show that our model outperforms state-of-the-art machine learning methods with a top-5 accuracy of around 80% for predicting the circuit topology and a parameter fitting error as low as 0.05%.
KW - Polymer membranes
KW - Electrochemical impedance spectroscopy
KW - Broadband dielectric spectroscopy
KW - Deep learning
KW - Machine learning
KW - Equivalent circuit
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602138
DO - https://doi.org/10.1016/j.electacta.2024.144474
SN - 0013-4686
VL - 496
SP - 1
EP - 13
PB - Elsevier Ltd.
AN - OPUS4-60213
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Merz, Benjamin
A1 - Schmidt, Jonathan
A1 - Poka, Konstantin
A1 - Mohr, Gunther
A1 - Polte, Julian
A1 - Hilgenberg, Kai
T1 - Impact of illumination technique on the detectability of irregularities in high-resolution images of visual in-situ process monitoring in Laser Powder Bed Fusion
N2 - The layerwise geometry build-up of additive manufacturing (AM) enables the possibility of in-situ process monitoring. The objective is the detection of irregularities during the build cycle, ensuring component quality and process stability. Focus of this work is the visual in-situ monitoring of the process of powder bed fusion with laser beam of metals (PBF-LB/M). Current state of the art visual monitoring systems for PBF-LB/M are limited by low resolution, allowing the detection of gross flaws. In this work a 65 Mpixel high-resolution monochrome camera is integrated into a commercial PBF-LB/M machine enabling a spatial resolution of approx. 17.2 µm/Pixel. The observed inhomogeneities are clustered into directly detectable irregularities, and indirectly detectable irregularities that can be inferred from the surface. In parallel, two different illumination techniques are realized in the process chamber and compared. The impact of the distinct illumination technique, direct light and dark field, on the identification of irregularities is evaluated.
KW - Powder bed fusion with laser beam of metals
KW - In-situ monitoring
KW - High-resolution camera
KW - Illumination technique
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610929
DO - https://doi.org/10.1016/j.procir.2024.08.079
SN - 2212-8271
VL - 124
SP - 98
EP - 103
PB - Elsevier B.V.
AN - OPUS4-61092
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martins, Inês C.B.
A1 - Al-Sabbagh, Dominik
A1 - Meyer, Klas
A1 - Maiwald, Michael
A1 - Scholz, G.
A1 - Emmerling, Franziska
T1 - Insight into the Structure and Properties of Novel Imidazole-Based Salts of Salicylic Acid
N2 - The preparation of new active pharmaceutical ingredient (API) multicomponent Crystal forms, especially co-crystals and salts, is being considered as a reliable strategy to improve API solubility and bioavailability. In this study, three novel imidazole-based salts of the poorly water-soluble salicylic acid (SA) are reported exhibiting a remarkable improvement in solubility and dissolution rate properties. All structures were solved by powder X-ray diffraction. Multiple complementary techniques were used to solve co-crystal/salt ambiguities: density functional Theory calculations, Raman and 1H/13C solid-state NMR spectroscopies. In all molecular salts, the Crystal packing interactions are based on a common charged assisted +N-H SA)...O-(co-former) hydrogen bond interaction. The presence of an extra methyl group in different positions of the co-former, induced different supramolecular arrangements, yielding salts with different physicochemical properties.
All salts present much higher solubility and dissolution rate than pure SA. The most promising results were obtained for the salts with imidazole and 1-methylimidazole co-formers.
KW - Salicylic acid
KW - Imidazole
KW - Salts
KW - Powder X-ray diffraction
KW - SsNMR
KW - DFT
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502825
DO - https://doi.org/10.3390/molecules24224144
VL - 24
IS - 22
SP - 4144
PB - MDPI
AN - OPUS4-50282
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Martins, Ines
A1 - Al-Sabbagh, Dominik
A1 - Bentrup, U.
A1 - Marquardt, Julien
A1 - Schmid, Thomas
A1 - Scoppola, E.
A1 - Kraus, Werner
A1 - Stawski, Tomasz
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Yusenko, Kirill
A1 - Weidner, Steffen
A1 - Emmerling, Franziska
T1 - Formation Mechanism of a Nano-Ring of Bismuth Cations and Mono-Lacunary Keggin-Type Phosphomolybdate
N2 - A new hetero-bimetallic polyoxometalate (POM) nano-ring was synthesized in a one-pot procedure. The structure consists of tetrameric units containing four bismuth-substituted monolacunary Keggin anions including distorted [BiO8] cubes. The nano-ring is formed via self-assembly from metal precursors in aqueous acidic medium. The compound (NH4)16[(BiPMo11O39)4] ⋅ 22 H2O; (P4Bi4Mo44) was characterized by single-crystal X-ray diffraction, extended X-ray absorption fine structure spectroscopy (EXAFS), Raman spectroscopy, matrix-assisted laser desorption/ionisation-time of flight mass spectrometry (MALDI-TOF), and thermogravimetry/differential scanning calorimetry mass spectrometry (TG-DSC-MS). The formation of the nano-ring in solution was studied by time-resolved in situ small- and wide-angle X-ray scattering (SAXS/WAXS) and in situ EXAFS measurements at the Mo−K and the Bi−L3 edge indicating a two-step process consisting of condensation of Mo-anions and formation of Bi−Mo-units followed by a rapid self-assembly to yield the final tetrameric ring structure.
KW - Bismuth
KW - In situ EXAFS
KW - In situ SAXS/WAXS
KW - Lacunary Keggin ion
KW - Polyoxometalates
KW - Self-assembly
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546823
DO - https://doi.org/10.1002/chem.202200079
SN - 0947-6539
VL - 28
IS - 27
SP - 1
EP - 7
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54682
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Willms, Thomas
A1 - Kryk, Holger
A1 - Hampel, Uwe
T1 - An improved method for the analysis of the reaction products of the partial isobutane oxidation by gas chromatography using a green solvent
N2 - In the present work, an improved GC/MS method for the analysis of the reaction products of the non-catalytic partial oxidation of isobutane at a starting temperature of 25°C has been developed and compared to a previously published method. Two green GC-solvents (dimethyl carbonate (DMC), diethyl carbonate (DEC)) and several internal standards (hexane, benzene, toluene, DEC) have been tested. The separation of the products at low retention times (methanol, isobutane, isobutene) could be significantly improved. For the liquid main products t-butyl hydroperoxide (TBHP), di-t-butyl peroxide (DTBP), t-butanol (TBA), propanone and most trace products (isopropanol, isobutanal, methyl formate, isopropyl formate, t-butyl formate and some acetates – 24 compounds in total), a coefficient of determination CoD > 0.999 has been achieved. For all weighing and GC/MS measurements uncertainties have been calculated. The peaks of the peak pair t-butyl formate (CoD >0.999) and isobutanol (CoD >0.99), have been simulated and used for calibrations. DEC gave a decomposition of TBHP on the column. With DMC, a problem of peak purity of TBHP appeared but could be resolved. The use of the green solvent DMC, compared to also studied traditional solvents like heptane and toluene, proved to be very beneficial, since it also permitted to determine polar compounds, e. g. carbon dioxide and formic acid.
KW - GC/MS
KW - Green solvent
KW - Method development
KW - Peroxide
KW - Measurement uncertainties
KW - Oxidation products
KW - Simulation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-632026
DO - https://doi.org/10.1016/j.chroma.2025.465892
SN - 0021-9673
VL - 1753
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-63202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Karkhin, V.
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - A General Analytical Solution for Two-Dimensional Columnar Crystal Growth during Laser Beam Welding of Thin Steel Sheets
N2 - A technique for calculating the main solidification parameters for a two-dimensional columnar crystal growth during complete penetration laser beam welding of thin steel sheets was developed. Given that the weld pool interface is described by Lamé curves (superellipses) within the horizontal plane of growth, general analytical solutions were derived for the geometry of the crystal axis and the corresponding growth rate and cross-sectional area of the crystal. A dimensionless analysis was performed to provide insights on the dependence of the solidification parameters on the shape and dimensions of the rear part of the weld pool boundary. The derived solutions were applied for the case of complete penetration laser beam keyhole welding of 2 mm thick 316L austenitic chromium-nickel steel sheets. It was shown that the reconstruction of the weld pool boundary with Lamé curves provides higher accuracy and flexibility compared to results obtained with elliptical functions. The validity of the proposed technique and the derived analytical solutions was backed up by a comparison of the obtained solutions to known analytical solutions and experimentally determined shapes and sizes of the crystals on the top surface of the sheet. The dimensions of the calculated crystal axis correlated well with the experimentally obtained results.
KW - General analytical solutions
KW - Two-dimensional solidification
KW - Columnar crystal growth
KW - Lamé curves
KW - Laser beam welding
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576788
DO - https://doi.org/10.3390/app13106249
IS - 10
SP - 1
EP - 10
ET - 13
AN - OPUS4-57678
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Influence of an external applied AC magnetic field on the melt pool dynamics at high-power laser beam welding
N2 - The study deals with the determination of the influence of an externally applied oscillating magnetic field on the melt pool dynamics in high power laser beam and hybrid laser arc welding processes. An AC magnet was positioned under the workpiece which is generating an upward directed electromagnetic force to counteract the formation of the droplets. To visualise the melt flow characteristics, several experiments were carried out using a special technique with mild steel from S355J2 with a plate thickness of up to 20 mm and a quartz glass in butt configuration. The profile of the keyhole and the melt flow were recorded with a highspeed camera from the glass side. Additionally, the influence of the magnetic field orientation to the welding direction on the filler material dilution on laser hybrid welding was studied with variating oscillation frequency. The element distribution over the whole seam thickness was measured with X-ray fluorescence (XRF). The oscillation frequency demonstrated a great influence on the melt pool dynamics and the mixing of the elements of the filler wire. The highspeed recordings showed, under the influence of the magnetic field, that the melt is affected under strong vortex at the weld root, which also avoids the formation of droplets.
T2 - 18th Nordic Laser Materials Processing Conference (18th NOLAMP)
KW - Laser beam welding
KW - AC magnetic field
KW - Melt pool dynamics
KW - Filler wire mixing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539231
DO - https://doi.org/10.1088/1757-899X/1135/1/012017
VL - 1135
IS - 012017
SP - 1
EP - 10
PB - IOP Publishing
AN - OPUS4-53923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Biegler, M.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Assessing the predictive capability of numerical additive manufacturing simulations via in-situ distortion measurements on a LMD component during build-up
N2 - Due to rapid, localized heating and cooling, distortions accumulate in additive manufactured laser metal deposition (LMD) components, leading to a loss of dimensional accuracy or even cracking. Numerical welding simulations allow the prediction of these deviations and their optimization before conducting experiments. To assess the viability of the simulation tool for the use in a predictive manner, comprehensive systems as well as to choose the optimal product matches, product analysis methods are needed. Indeed, most of the known methods aim to analyze a product or one product family on the physical level. Different product families, however, may differ largely in terms of the number and nature of components. This fact impedes an efficient comparison and choice of appropriate product family combinations for the production system. A new methodology is proposed to analyze existing products in view of their functional and physical architecture. The aim is to Cluster these products in new assembly oriented product families for the optimization.
KW - Laser metal deposition
KW - Directed Energy Deposition
KW - DED
KW - Welding Simulation
KW - Digital Image Correlation
KW - Cimensional Accuracy
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502567
DO - https://doi.org/10.1016/j.procir.2018.08.069
VL - 74
SP - 158
EP - 162
PB - Elsevier
AN - OPUS4-50256
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jokisch, T.
A1 - Marko, A.
A1 - Gook, S.
A1 - Üstündag, Ö.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Laser Welding of SLM-Manufactured Tubes Made of IN625 and IN718
N2 - The advantage of selective laser melting (SLM) is its high accuracy and geometrical flexibility.
Because the maximum size of the components is limited by the process chamber, possibilities must be found to combine several parts manufactured by SLM. An application where this is necessary, is, for example, the components of gas turbines, such as burners or oil return pipes, and inserts, which can be joined by circumferential welds. However, only a few investigations to date have been carried out for the welding of components produced by SLM. The object of this paper is, therefore, to investigate the feasibility of laser beam welding for joining SLM tube connections made of nickel-based alloys.
For this purpose, SLM-manufactured Inconel 625 and Inconel 718 tubes were welded with a Yb:YAG disk laser and subsequently examined for residual stresses and defects. The results showed that the welds had no significant influence on the residual stresses. A good weld quality could be achieved in the seam circumference. However, pores and pore nests were found in the final overlap area, which meant that no continuous good welding quality could be accomplished. Pore formation was presumably caused by capillary instabilities when the laser power was ramped out.
KW - Inconel 718
KW - Laser welding
KW - Selective Laser Melting
KW - Laser Powder Bed Fusion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489679
DO - https://doi.org/10.3390/ma12182967
SN - 1996-1944
VL - 12
IS - 18
SP - 2967, 1
EP - 15
PB - Multidisciplinary Digital Publishing Institute
CY - Basel
AN - OPUS4-48967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ö.
A1 - Avilov, V.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Improvement of Filler Wire Dilution Using External Oscillating Magnetic Field at Full Penetration Hybrid Laser-Arc Welding of Thick Materials
N2 - Hybrid laser-arc welding offers many advantages, such as deep penetration, good gap bridge-ability, and low distortion due to reduced heat input. The filler wire which is supplied to the process is used to influence the microstructure and mechanical properties of the weld seam.
A typical problem in deep penetration high-power laser beam welding with filler wire and hybrid laser-arc welding is an insufficient mixing of filler material in the weld pool, leading to a non-uniform element distribution in the seam. In this study, oscillating magnetic fields were used to form a non-conservative component of the Lorentz force in the weld pool to improve the element Distribution over the entire thickness of the material. Full penetration hybrid laser-arc welds were performed on 20-mm-thick S355J2 steel plates with a nickel-based wire for different arrangements of the oscillating magnetic field. The Energy-dispersive X-ray spectroscopy (EDS) data for the distribution of two tracing elements (Ni and Cr) were used to analyze the homogeneity of dilution of the filler wire.
With a 30° turn of the magnetic field to the welding direction, a radical improvement in the filler material distribution was demonstrated. This would lead to an improvement of the mechanical properties with the use of a suitable filler wire.
KW - Thick materials
KW - Hybrid laser-arc welding
KW - Oscillating magnetic field
KW - Electromagnetic stirring
KW - Full penetration
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-489644
DO - https://doi.org/10.3390/met9050594
SN - 2075-4701
VL - 9
IS - 5
SP - 594
PB - Multidisciplinary Digital Publishing Institute
CY - Basel
AN - OPUS4-48964
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gook, S.
A1 - Krieger, S.
A1 - Gumenyuk, Andrey
A1 - El-Batahgy, A. M.
A1 - Rethmeier, Michael
T1 - Notch impact toughness of laser beam welded thick sheets of cryogenic nickel alloyed steel X8Ni9
N2 - The paper deals with the investigations of the impact toughness of laser beam welded 14.5 mm thick sheets made of cryogenic steel X8Ni9 as a function of preheating. This 9% nickel alloyed steel is widely used in the liquefied natural gas (LNG) industry. An application of highly efficient welding processes such as high-power laser beam welding (LBW) in LNG sector requires an understanding of the interactions between the LBW process parameters and weld properties, in particular the impact toughness. The results show that the original fine-grained martensitic microstructure of the base metal (BM) is significantly changed by melting and crystallization during the LBW, what can lead to a decrease in the impact toughness of the weld metal (WM) below the required level. An optimal preheating temperature range leads to the favorable thermal welding cycle and is of remarkable importance for maintaining the notch impact toughness of laser beam welded joints of these thick steel sheets. A parameter window was identified in which V-notch impact toughness comparable to that of the BM at -196 °C was achieved.
KW - Cryogenic steel
KW - Laser beam welding
KW - Preheating
KW - Welding thermal cycle
KW - Microstructure
KW - Hardness
KW - V-notch impact toughness
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513250
DO - https://doi.org/10.1016/j.procir.2020.09.095
VL - 94
SP - 627
EP - 631
PB - Elsevier B.V.
AN - OPUS4-51325
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lange, Fritz
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
A1 - Hilgenberg, Kai
T1 - Numerical simulation of the weld pool dynamics during pulsed laser welding using adapted heat source models
N2 - A transient simulation including the impact of the laser energy, the melting of the metal and the development of the weld pool was conducted to observe the evolution of the vapor capillary and the solidification of the melt in pulsed laser beam welding of AISI 304 steel. The phase field method was implemented to investigate the evolution and behavior of the liquid-gas interface during welding and to describe the condensed and vapor phases. The effects of phase transition, recoil pressure, thermo-capillary and natural convection, vaporization and temperature dependent material properties were taken into account. A Gaussian-like heat source under consideration of the Fresnel absorption model was used to model the energy input of the laser beam. The heat source model was extended by a newly developed empirical approach of describing multiple beam reflections in the keyhole. To validate this new model, the numerical results were compared to experimental data and good agreement regarding the size and shape of the weld pool was observed.
T2 - LANE Conference 2018
CY - Fürth, Germany
DA - 03.09.2018
KW - Pulsed laser beam welding
KW - Weld pool dynamics
KW - Multiple reflections
KW - Vaporization
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-458749
DO - https://doi.org/10.1016/j.procir.2018.08.044
SN - 2212-8271
VL - 74
SP - 679
EP - 682
PB - Elsevier Ltd.
CY - Amsterdam [u.a.]
AN - OPUS4-45874
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gebhardt, M.O.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Numerical analysis of hot cracking in laser-hybrid welded tubes
N2 - In welding experiments conducted on heavy wall pipes, the penetration mode (full or partial penetration) occurred to be a significant factor influencing appearance of solidification cracks. To explain the observed phenomena and support further optimization of manufacturing processes, a computational model was developed, which used a sophisticated strategy to model the material. High stresses emerged in the models in regions which showed cracking during experiments. In partial penetration welding, they were caused by the prevention of weld shrinkage due to the cold and strong material below the joint. Another identified factor having an influence on high stress localization is bulging of the weld.
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-302961
DO - https://doi.org/10.1155/2013/520786
SN - 1687-8442
SN - 1687-8434
IS - Article ID 520786
SP - 1
EP - 8
PB - Hindawi Publishing Corporation
CY - New York, NY, USA
AN - OPUS4-30296
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brunner-Schwer, C.
A1 - Kersting, R.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Laser-plasma-cladding as a hybrid metal deposition-technology applying a SLM-produced copper plasma nozzle
N2 - Laser-Metal-Deposition (LMD) and Plasma-Transferred-Arc (PTA) are well known Technologies which can be used for cladding purposes. The prime objective in combining LMD and PTA as a Hybrid Metal Deposition-Technology (HMD) is to achieve high Deposition rates at low thermal Impact. Possible applications are coatings for wear protection or repair welding for components made of steel. The two energy sources (laser and Plasma arc) build a Joint process Zone and are configurated to constitute a stable process at laser powers between 0.4-1 kW (defocused) and Plasma currents between 75-200 A. Stainless steel 316L serves as filler material. For this HMD process, a Plasma Cu-nozzle is designed and produced by powder bed based Selective Laser Melting. The potential of the HMD Technology is investigated and discussed considering existing process. This paper demonstrates how the interaction of the two energy sources effects the following application-relevant properties: Deposition rate, powder Efficiency and energy Input.
T2 - LANE 2018
CY - Fürth, Germany
DA - 3.09.2018
KW - Laser-metal-deposition
KW - Plasma-transferred-arc
KW - SLM printed plasma torch
KW - Laser-plasma hybrid
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-470999
UR - 10.1016/j.procir.2018.08.020
DO - https://doi.org/10.1016/j.procir.2018.08.020
SN - 2212-8271
VL - CIRP 74
SP - 738
EP - 742
PB - Sciencedirect
CY - Berlin
AN - OPUS4-47099
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Pavlov, V.
A1 - Volvenko, S.
A1 - Rethmeier, Michael
T1 - In situ determination of the critical straining condition for solidification cracking during laser beam welding
N2 - A self-restraint hot cracking test (free edge test) was used in combination with a novel optical measurement technique to determine the critical straining conditions for solidification cracking for the stainless steel grade 1.4828 (AISI 309). The Lucas-Kanade algorithm for the optical flow (OF) calculation was implemented to obtain the full-field displacement and then the full-field strain.
The use of external laser illumination with appropriate filters allows to obtain good image quality with good contrast. The critical straining conditions required for solidification cracking can be obtained by means the proposed technique in the immediate vicinity of the solidification front. A very good repeatability was demonstrated for the used measurement technique. The critical straining conditions for solidification cracking for the tested steel und under this welding conditions has been detected
KW - Laser beam welding
KW - Solidification cracking
KW - Critical strain
KW - Critical strain rate
KW - Optical flow
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513070
DO - https://doi.org/10.1016/j.procir.2020.09.104
SN - 2212-8271
VL - 94
SP - 666
EP - 670
PB - Elsevier
AN - OPUS4-51307
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Distortion-based validation of the heat treatment simulation of Directed Energy Deposition additive manufactured parts
N2 - Directed energy deposition additive manufactured parts have steep stress gradients and an anisotropic microstructure caused by the rapid thermo-cycles and the layer-upon-layer manufacturing, hence heat treatment can be used to reduce the residual stresses and to restore the microstructure. The numerical simulation is a suitable tool to determine the parameters of the heat treatment process and to reduce the necessary application efforts. The heat treatment simulation calculates the distortion and residual stresses during the process. Validation experiments are necessary to verify the simulation results. This paper presents a 3D coupled thermo-mechanical model of the heat treatment of additive components. A distortion-based validation is conducted to verify the simulation results, using a C-ring shaped specimen geometry. Therefore, the C-ring samples were 3D scanned using a structured light 3D scanner to compare the distortion of the samples with different post-processing histories.
KW - Directed Energy Deposition
KW - Additive Manufacturing
KW - Heat Treatment
KW - Numerical Simulation
KW - Finite Element Method
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513153
DO - https://doi.org/10.1016/j.procir.2020.09.146
VL - 94
SP - 362
EP - 366
PB - Elsevier B.V.
AN - OPUS4-51315
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Petrat, T.
A1 - Kersting, R.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Embedding electronics into additive manufactured components using laser metal deposition and selective laser melting
N2 - The paper deals with the integration of a light emitting diode (LED) into an additive manufactured metal component. Selective laser melting (SLM) and laser metal deposition (LMD) are used. The material used is the chrome-nickel steel 316L. The basic component is manufactured by means of SLM and consists of a solid body and an area with grid structure. The solid body includes a duct in the shape of a groove with a recess for the positioning of the power cable. The LED is embedded in the grid structure via an inlet from the solid body. In further processing, the groove is filled with LMD. Two strategies with different parameter combinations were investigated. It shows that a high energy input near the power cable leads to its destruction. By using multiple parameter combinations during the manufacturing process, this destruction can be prevented. There was a comparison of both strategies with regard to the necessary number of tracks and duration of welding time.
KW - Additive manufacturing
KW - Condition monitoring
KW - Process chain
KW - Laser-metal-deposition
KW - Selektive-laser-melting
KW - Embedded electronics
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479469
DO - https://doi.org/10.1016/j.procir.2018.08.071
SP - 168
EP - 171
PB - Elsevier Ltd.
AN - OPUS4-47946
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaumann, P.
A1 - Schürmann, K.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Automatically Welded Tubular X-Joints for Jacket Substructures
N2 - To increase the competitiveness of jacket substructures compared to monopiles a changeover from an individual towards a serial jacket production based on automated manufactured tubular joints combined with standardized pipes has to be achieved. Therefore, this paper addresses fatigue tests of automatically welded tubular X-joints focusing on the location of the technical fatigue crack. The detected location of the technical crack is compared to numerical investigations predicting the most fatigue prone notch considering the structural stress approach as well as the notch stress approach. Besides, the welding process of the automated manufactured tubular X-joints is presented.
KW - Tubular X-joints
KW - Fatigue tests
KW - Technical crack detection
KW - Local fatigue spproaches
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513228
DO - https://doi.org/10.1002/cepa.1140
VL - 3
IS - 3-4
SP - 823
EP - 828
PB - Ernst & Sohn Verlag für Architektur und technische Wissenschaften GmbH & Co. KG
CY - Berlin
AN - OPUS4-51322
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Naik, Aakash
A1 - Ertural, Christina
A1 - Dhamrait, Nidal
A1 - Benner, Philipp
A1 - George, Janine
T1 - A Quantum-Chemical Bonding Database for Solid-State Materials
N2 - An in-depth insight into the chemistry and nature of the individual chemical bonds is essential for understanding materials. Bonding analysis is thus expected to provide important features for large-scale data analysis and machine learning of material properties. Such chemical bonding information can be computed using the LOBSTER software package, which post-processes modern density functional theory data by projecting the plane wave-based wave functions onto an atomic orbital basis. With the help of a fully automatic workflow, the VASP and LOBSTER software packages are used to generate the data. We then perform bonding analyses on 1520 compounds (insulators and semiconductors) and provide the results as a database. The projected densities of states and bonding indicators are benchmarked on standard density-functional theory computations and available heuristics, respectively. Lastly, we illustrate the predictive power of bonding descriptors by constructing a machine learning model for phononic properties, which shows an increase in prediction accuracies by 27% (mean absolute errors) compared to a benchmark model differing only by not relying on any quantum-chemical bonding features.
KW - Bonding Analysis
KW - DFT
KW - High-throughput
KW - Database
KW - Phonons
KW - Machine Learning
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582892
DO - https://doi.org/10.1038/s41597-023-02477-5
VL - 10
IS - 1
SP - 1
EP - 18
AN - OPUS4-58289
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nowatzky, Yannek
A1 - Benner, Philipp
A1 - Reinert, K.
A1 - Muth, Thilo
T1 - Mistle: bringing spectral library predictions to metaproteomics with an efficient search index
N2 - Motivation: Deep learning has moved to the forefront of tandem mass spectrometry-driven proteomics and authentic prediction for peptide fragmentation is more feasible than ever. Still, at this point spectral prediction is mainly used to validate database search results or for confined search spaces. Fully predicted spectral libraries have not yet been efficiently adapted to large search space problems that often occur in metaproteomics or proteogenomics.
Results: In this study, we showcase a workflow that uses Prosit for spectral library predictions on two common metaproteomes and implement an indexing and search algorithm, Mistle, to efficiently identify experimental mass spectra within the library. Hence, the workflow emulates a classic protein sequence database search with protein digestion but builds a searchable index from spectral predictions as an in-between step.
We compare Mistle to popular search engines, both on a spectral and database search level, and provide evidence that this approach is more accurate than a database search using MSFragger. Mistle outperforms other spectral library search engines in terms of run time and proves to be extremely memory efficient with a 4- to 22-fold decrease in RAM usage. This makes Mistle universally applicable to large search spaces, e.g. covering comprehensive sequence databases of diverse microbiomes.
Availability and implementation: Mistle is freely available on GitHub at https://github.com/BAMeScience/Mistle.
KW - Mass spectrometry
KW - Proteomics
KW - Algorithms
KW - Metaproteomics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579373
DO - https://doi.org/10.1093/bioinformatics/btad376
SN - 1367-4811
VL - 39
IS - 6
SP - 1
EP - 12
PB - Oxford University Press
CY - Oxford, Great Britain
AN - OPUS4-57937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Process Setup and Boundaries of Wire Electron Beam Additive Manufacturing of High-Strength Aluminum Bronze
N2 - In recent years, in addition to the commonly known wire-based processes of Directed Energy Deposition using lasers, a process variant using the electron beam has also developed to industrial market maturity. The process variant offers particular potential for processing highly conductive, reflective or oxidation-prone materials. However, for industrial usage, there is a lack of comprehensive data on performance, limitations and possible applications. The present study bridges the gap using the example of the high-strength aluminum bronze CuAl8Ni6. Multi-stage test welds are used to determine the limitations of the process and to draw conclusions about the suitability of the parameters for additive manufacturing. For this purpose, optimal ranges for energy input, possible welding speeds and the scalability of the process were investigated. Finally, additive test specimens in the form of cylinders and walls are produced, and the hardness profile, microstructure and mechanical properties are investigated. It is found that the material CuAl8Ni6 can be well processed using wire electron beam additive manufacturing. The microstructure is similar to a cast structure, the hardness profile over the height of the specimens is constant, and the tensile strength
and elongation at fracture values achieved the specification of the raw material.
KW - Wire electron beam additive manufacturing
KW - Aluminum bronze
KW - Wire-based additive manufacturing
KW - EBAM
KW - DED-EB
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580890
DO - https://doi.org/10.3390/met13081416
VL - 13
IS - 8
SP - 1
EP - 16
PB - MDPI
AN - OPUS4-58089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Huo, W.
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
A1 - Wolter, K.
T1 - Strain Prediction Using Deep Learning during Solidification Crack Initiation and Growth in Laser Beam Welding of Thin Metal Sheets
N2 - The strain field can reflect the initiation time of solidification cracks during the welding process. The traditional strain measurement is to first obtain the displacement field through digital image correlation (DIC) or optical flow and then calculate the strain field. The main disadvantage is that the calculation takes a long time, limiting its suitability to real-time applications. Recently, convolutional neural networks (CNNs) have made impressive achievements in computer vision.
To build a good prediction model, the network structure and dataset are two key factors. In this paper, we first create the training and test sets containing welding cracks using the controlled tensile weldability (CTW) test and obtain the real strain fields through the Lucas–Kanade algorithm. Then, two new networks using ResNet and DenseNet as encoders are developed for strain prediction, called StrainNetR and StrainNetD. The results show that the average endpoint error (AEE) of the two networks on our test set is about 0.04, close to the real strain value. The computation time could be reduced to the millisecond level, which would greatly improve efficiency.
KW - Convolutional neural network
KW - Strain fields prediction
KW - Laser beam welding
KW - Solidification cracking
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-570565
DO - https://doi.org/10.3390/app13052930
VL - 13
IS - 5
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-57056
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El-Sari, B.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Investigation of the LME Susceptibility of Dual Phase Steel with Different Zinc Coatings
N2 - The application of anti-corrosion coated, high-strength steels in the automotive industry has increased in recent years. In combination with various zinc-based surface coatings, liquid metal embrittlement cracking can be observed in some of these materials. A high-quality, crack-free spot-welded joint is essential to realize the lightweight potential of the materials. In this work, the LME susceptibility of different coatings, which will be determined by the crack length and the occurrence rate, will be investigated using a welding under external load setup. The uncoated specimens did not show any LME. EG, GI and GA showed significantly less LME than ZM coatings. The latter coatings showed much larger crack lengths than the EG, GI and GA coatings. Furthermore, two mechanisms regarding the LME occurrence rate were observed: the occurrence of LME in zinc–magnesium coatings was theorized to be driven by the material properties of the coatings, whereas the occurrence of LME at EG, GI and GA samples was forced mainly by the application of the external tensile load.
In the experimental setup of this work, the materials were exposed to unusually high mechanical loads (up to 80% of their yield strength) to evoke LME cracks.
KW - Widerstandspunktschweißen
KW - Hochfester Stahl
KW - Liquid Metal Embrittlement
KW - Flüssigmetallinduzierte Rissbildung
KW - Zink
KW - AHSS
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-580428
DO - https://doi.org/10.3390/met13050890
VL - 13
IS - 5
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-58042
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nowatzky, Yannek
A1 - Russo, Francesco Friedrich
A1 - Lisec, Jan
A1 - Kister, Alexander
A1 - Reinert, Knut
A1 - Muth, Thilo
A1 - Benner, Philipp
T1 - FIORA: Local neighborhood-based prediction of compound mass spectra from single fragmentation events
N2 - Non-targeted metabolomics holds great promise for advancing precision medicine and biomarker discovery. However, identifying compounds from tandem mass spectra remains a challenging task due to the incomplete nature of spectral reference libraries. Augmenting these libraries with simulated mass spectra can provide the necessary references to resolve unmatched spectra, but generating high-quality data is difficult. In this study, we present FIORA, an open-source graph neural network designed to simulate tandem mass spectra. Our main contribution lies in utilizing the molecular neighborhood of bonds to learn breaking patterns and derive fragment ion probabilities. FIORA not only surpasses state-of-the-art fragmentation algorithms, ICEBERG and CFM-ID, in prediction quality, but also facilitates the prediction of additional features, such as retention time and collision cross section. Utilizing GPU acceleration, FIORA enables rapid validation of putative compound annotations and large-scale expansion of spectral reference libraries with high-quality predictions.
KW - Metabolomics
KW - Machine Learning
KW - Mass spectrometry
KW - Bioinformatics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-627585
DO - https://doi.org/10.1038/s41467-025-57422-4
SN - 2041-1723
VL - 16
IS - 1
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-62758
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - Wang, Zhuoqun
A1 - Haak, Viktor
A1 - Olfert, Viktoria
A1 - El-Sari, Bassel
A1 - Hein, David
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - A novel welding schedule for expanding the expulsion-free process window in resistance spot welding of dissimilar joints with ultra-high strength steel
N2 - This study introduces a novel approach to expanding the maximum expulsion-free process window in resistance spot welding (RSW) of dissimilar joints between ultra-high strength steel (UHSS) and mild steel. Quantitative analysis revealed that expulsion is driven by the interaction between nugget growth rate and plastic shell thickness. Based on this finding, the welding schedule was optimized by applying a preheating current to form an initial plastic shell, followed by a ramp-up current profile during the main welding phase. Welding simulations indicated that the ramp-up current slowed nugget growth, improved plastic shell formation, and prevented nugget breakthrough, thereby reducing the risk of expulsion. Experimental validation showed a 19 % increase in maximum expulsion-free heat input, with the nugget diameter increasing by 7.6 % to 8.94 mm compared to the reference welding schedule. Furthermore, even when expulsion occurred beyond the process window, this optimization delayed its occurrence, minimizing its impact on spot weld quality. Finally, the optimized welding schedule also exhibited significant robustness. Despite a 2 mm initial gap disturbance, the maximum expulsionfree heat input increased by 57 %, while the nugget diameter grew by 30 % to 8.92 mm. These results confirm that the proposed approach effectively extends the process window by preventing expulsion and enhances process stability.
KW - Expulsion
KW - Resistance spot welding
KW - Finite element modelling
KW - Preheating
KW - Ultra-high-strength steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626877
DO - https://doi.org/10.1016/j.jmapro.2025.02.009
SN - 2212-4616
VL - 137
SP - 306
EP - 309
PB - Elsevier BV
AN - OPUS4-62687
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmidt, Jonathan
A1 - Merz, Benjamin
A1 - Poka, Konstantin
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Surface structure analysis using visual high-resolution in situ process monitoring in laser powder bed fusion
N2 - Parameter studies are a common step in selecting process parameters for laser powder bed fusion of metals (PBF-LB/M). Density cubes are commonly used for this purpose. Density cubes manufactured with varied process parameters can exhibit distinguishable surface structures visible to the human eye. The layer-wise process enables such surface structures to be detected during manufacturing. However, industrial visual in situ monitoring systems for PBF-LB/M currently have limited resolution and are incapable of reliably capturing small differences in the surface structures. In this work, a 65 MPixel high-resolution monochrome camera was integrated into an industrial PBF-LB/M machine together with a high-intensity LED (light-emitting diode) bar. Post-exposure images were taken to analyse differences in light reflection of fused areas. It is revealed that the grey-level co-occurrence matrix can be used to quantify the visual surface structure of nickel-based superalloy Inconel®939 density cubes per layer. The properties of the grey-level co-occurrence matrix correlate to the energy input and the resulting porosity of density cubes. Low-energy samples containing lack of fusion flaws show an increased contrast in the grey-level co-occurrence matrix compared to specimens with optimal energy input. The potential of high-resolution images for quality assurance via in situ process monitoring in PBF-LB/M is further discussed.
KW - Additive manufacturing
KW - Powder bed fusion
KW - In situ monitoring
KW - Image processing
KW - High resolution camera
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626685
DO - https://doi.org/10.1007/s40194-025-01955-1
SN - 1878-6669
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
AN - OPUS4-62668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Savitsky, Viktor
A1 - Schmies, Lennart
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Comparative performance of DIC and optical flow algorithms for displacement and strain analysis in laser beam welding
N2 - The measurement of strain and displacement in the context of the welding process represents a significant challenge. Optical methods, such as digital image correlation (DIC) or optical flow algorithms, have demonstrated their efficacy in robust and reliable data acquisition in harsh environments, including those encountered in welding processes. Concurrently, a trade-off between the accuracy of the measurement and the computational resources required for the associated calculations must be evaluated on a case-by-case basis. The application of filters to initial images represents a technique that serves to enhance the quality and accuracy of the strain and displacement prediction. In the present study, the estimated error of two algorithms, namely the Lucas-Kanade (LK) and the inverse compositional Gauss-Newton (IC-GN), is compared on the basis of both synthetic and real welding images. The displacement field is evaluated for different zones in the laser weld seam with varying contrast performance. Based on the aforementioned results, a strain calculation was conducted for both methods, which yielded comparable results for the LK and IC-GN algorithms.
KW - Laser speckle
KW - DIC
KW - Optical flow
KW - Error estimation
KW - Strain measurement
KW - Laser beam welding
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625919
DO - https://doi.org/10.1016/j.optlaseng.2025.108870
SN - 1873-0302
VL - 187
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-62591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schmolke, Tobias
A1 - Brunner-Schwer, Christian
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - On welding of high-strength steels using laser beam welding and resistance spot weld bonding with emphasis on seam leak tightness
N2 - The design of most electric vehicles provides for the positioning of the heavy energy storage units in the underbody of the cars. In addition to crash safety, the battery housing has to meet high requirements for gas tightness. In order to test the use of high-strength steels for this sub-assembly, this paper examines welded joints utilizing resistance spot weld bonding and laser remote welding, with special regard to the gas tightness of the welds. For this purpose, the pressure difference test and helium sniffer leak detection are presented and applied. The combination of both leak test methods has proven ideal in experimental investigations. For laser remote welding, gas-tight seams can be achieved with an inter-sheet gap of 0.1 mm, even if occasionally leaking samples cannot be prevented. Resistance spot welding suits gas-tight joining with both one- and two-component adhesives. Against the background of leak tightness, process fluctuations that lead to weld spatter and defects in the adhesive layer must be prevented with high priority.
KW - Resistance spot weld bonding
KW - Laser welding
KW - Seam leak tightness
KW - High-strength steel
KW - Leak testing
KW - Helium sniffer leak detection
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624250
DO - https://doi.org/10.3390/jmmp7030116
SN - 2504-4494
VL - 7
IS - 3
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-62425
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schartel, Bernhard
T1 - Phosphorus-based flame retardancy mechanisms - Old hat or a starting point for future development?
N2 - Different kinds of additive and reactive flame retardants containing phosphorus are increasingly successful as halogen-free alternatives for various polymeric materials and applications. Phosphorus can act in the condensed phase by enhancing charring, yielding intumescence, or through inorganic glass formation; and in the gas phase through flame inhibition. Occurrence and efficiency depend, not only on the flame retardant itself, but also on its interaction with pyrolysing polymeric material and additives. Flame retardancy is sensitive to modification of the flame retardant, the use of synergists/adjuvants, and changes to the polymeric material. A detailed understanding facilitates the launch of tailored and targeted development.
KW - Fire retardancy
KW - Red phosphorus
KW - Phosphate
KW - Phosphonate
KW - Phosphinate
KW - Phosphine oxide
KW - Flame inhibition
KW - Charring
KW - Intumescence
PY - 2010
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-220368
DO - https://doi.org/10.3390/ma3104710
SN - 1996-1944
VL - 3
IS - 10
SP - 4710
EP - 4745
PB - MDPI
CY - Basel
AN - OPUS4-22036
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Eisenbart, Miriam
A1 - Hanke, Thomas
A1 - Bauer, Felix
A1 - Beygi Nasrabadi, Hossein
A1 - Junghanns, Kurt
A1 - Dziwis, Gordian
A1 - Tikana, Ladji
A1 - Parvez, Ashak Mahmud
A1 - van den Boogaart, Karl Gerald
A1 - Sajjad, Mohsin
A1 - Friedmann, Valerie
A1 - Preußner, Johannes
A1 - Ramakrishnan, Anantha Narayanan
A1 - Klengel, Sandy
A1 - Meyer, Lars‐Peter
A1 - Martin, Michael
A1 - Klotz, Ulrich Ernst
A1 - Skrotzki, Birgit
A1 - Weber, Matthias
T1 - KupferDigital: Ontology‐Based Digital Representation for the Copper Life Cycle
N2 - The copper life cycle comprises numerous stages from the alloy production to the manufacturing and usage of engineered parts until recycling. At each step, valuable data are generated and stored; some are transferred to the subsequent stations. A thorough understanding of the materials’ behavior during manufacturing processes or throughout their product lifetime is highly dependent on a reliable data transfer. If, for example, a failure occurs during the service life, information about the manufacturing route can be of decisive importance for detecting the root cause of the failure. Additionally, the life cycle assessment hinges on the availability of data. Recording and storing interoperable structured data is, therefore, a thriving research field with huge implications for the economic strength of the manufacturing industry. In the KupferDigital project, it is demonstrated how an ontology‐based data space can be utilized not only as an innovative method for storing and providing interoperable life cycle data but also as a means to enable automated data analysis and evaluation, leading to new insights and the creation of new knowledge using semantic data and technologies. This work illustrates how data recorded at different research facilities can be integrated into one single data space, allowing queries across heterogeneous sources.
KW - Copper Alloy
KW - Ontology
KW - Digitalization
KW - Data Space
KW - Semantic Representation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630213
SN - 1527-2648
DO - https://doi.org/10.1002/adem.202401735
VL - 27
IS - 8
SP - 1
EP - 29
PB - Wiley
AN - OPUS4-63021
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Hanke, T.
A1 - Muth, Thilo
A1 - Riedel, Jens
A1 - Schilling, Markus
A1 - Schweizer, C.
A1 - Skrotzki, Birgit
A1 - Todor, A.
A1 - Moreno Torres, Benjami
A1 - Unger, Jörg F.
A1 - Völker, Christoph
A1 - Olbricht, Jürgen
T1 - A Perspective on Digital Knowledge Representation in Materials Science and Engineering
N2 - The amount of data generated worldwide is constantly increasing. These data come from a wide variety of sources and systems, are processed differently, have a multitude of formats, and are stored in an untraceable and unstructured manner, predominantly in natural language in data silos. This problem can be equally applied to the heterogeneous research data from materials science and engineering. In this domain, ways and solutions are increasingly being generated to smartly link material data together with their contextual information in a uniform and well-structured manner on platforms, thus making them discoverable, retrievable, and reusable for research and industry. Ontologies play a key role in this context. They enable the sustainable representation of expert knowledge and the semantically structured filling of databases with computer-processable data triples.
In this perspective article, we present the project initiative Materials-open-Laboratory (Mat-o-Lab) that aims to provide a collaborative environment for domain experts to digitize their research results and processes and make them fit for data-driven materials research and development. The overarching challenge is to generate connection points to further link data from other domains to harness the promised potential of big materials data and harvest new knowledge.
KW - Data infrastructures
KW - Digital representations
KW - Digital workflows
KW - Knowledge graphs
KW - Materials informatics
KW - Ontologies
KW - Vocabulary providers
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546729
DO - https://doi.org/10.1002/adem.202101176
SN - 1438-1656
SP - 1
EP - 14
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-54672
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bibinger, J.
A1 - Eibl, S.
A1 - Gudladt, H.-J.
A1 - Schartel, Bernhard
A1 - Höfer, P.
T1 - Pushing the limits of thermal resistance in nanocomposites: A comparative study of carbon black and nanotube modifications
N2 - Enhancing the thermal resistance of carbon fiber-reinforced polymers (CFRPs) with flame retardants or coatings often leads to increased weight and reduced mechanical integrity. To address these challenges, this study introduces an innovative approach for developing nanocomposites using carbon-based nanoparticles, while preserving the structural lightweight properties. For this, carbon black particles (CBPs) up to 10% and carbon nanotubes (CNTs) up to 1.5% were incorporated into the RTM6/G939 composite material. The obtained samples were then analyzed for their properties and heat resistance under one-sided thermal loading at a heat flux of 50 kW/m2. Results demonstrate that integrating these particles improves heat conduction without compromising the material’s inherent advantages. As a result, thermo-induced damage and the resulting loss of mechanical strength are delayed by 17% with CBPs and 7% with CNTs compared to the unmodified material. Thereby, the thermal behavior can be accurately modeled by a straightforward approach, using calibrated, effective measurements of the nanoparticles in the polymer matrix rather than relying on theoretical assumptions. This approach thus provides a promising methode to characterize and improve thermal resistance without significant trade-offs.
KW - Nanomaterial
KW - Cabon fiber-reinforced polymer (CFRP)
KW - Carbon black (CB)
KW - Carbon nanotube (CNT)
KW - Improving heat conduction
KW - Prediction thermal properties
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-628632
DO - https://doi.org/10.3390/nano15070546
SN - 2079-4991
VL - 15
IS - 7
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-62863
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis
A1 - Graf, B.
A1 - Rehmer, Birgit
A1 - Petrat, T.
A1 - Skrotzki, Birgit
A1 - Rethmeier, Michael
T1 - Characterization of Ti-6Al-4V fabricated by multilayer laser powder-based directed energy deposition
N2 - Laser powder-based directed energy deposition (DED-L) is increasingly being used in additive manufacturing (AM). As AM technology, DED-L must consider specific challenges. It must achieve uniform volume growth over hundreds of layers and avoid heat buildup of the deposited material. Herein, Ti–6Al–4V is fabricated using an approach that addresses these challenges and is relevant in terms of transferability to DED–L applications in AM. The assessment of the obtained properties and the discussion of their relationship to the process conditions and resulting microstructure are presented. The quality of the manufacturing process is proven in terms of the reproducibility of properties between individual blanks and with respect to the building height. The characterization demonstrates that excellent mechanical properties are achieved at room temperature and at 400 °C.
KW - AGIL
KW - Laser powder-based directed energy deposition
KW - Tensile properties
KW - Ti-6Al-4V
KW - Microstructure
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542262
DO - https://doi.org/10.1002/adem.202101333
SN - 1438-1656
SN - 1527-2648
SP - 1
EP - 15
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54226
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zirnstein, Benjamin
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
T1 - Combination of phosphorous flame retardants and aluminum trihydrate in multicomponent EPDM composites
N2 - Ethylene propylene diene monomer (EPDM) Rubbers with the flame retardants tris(2-ethylhexyl)phosphate, ammonium polyphosphate, polyaniline, and aluminum trihydroxide were prepared and analyzed in this study. The homogenous dispersion of the fillers in the rubber matrix was confirmed by scanning electron microscope. To investigate the interplay of the different flame retardants, the flame retardants were varied systematically. The comprehensive study sought combinations of flame retardants that allow high loadings of flame retardants without deterioration of the physical and mechanical properties of the EPDM rubber. The eight EPDM rubbers were investigated via thermogravimetric analysis and pyrolysis gas chromatography coupled with a mass spectrometer (Py GC/MS) to investigate the potential synergistic effects. In the Py-GC/MS experiments, 27 pyrolysis products were identified. Furthermore, UL 94, limiting oxygen index, FMVSS 302, glow wire tests, and cone calorimeter tests were carried out. In the cone calorimeter test the EPDM rubbers R-1AP and R-1/2P achieved an increase in residue at flameout of 76% and a reduction in total heat evolved of about 35%. Furthermore, the compounds R-1AP and R-1/2P achieved a reduction in MARHE to about 150 kW m−1, a reduction of over 50% compared to the unprotected rubber R.
KW - EPDM
KW - Rubber
KW - Aluminum hydroxide (ATH)
KW - Phosphorous flame retardant
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-502859
DO - https://doi.org/10.1002/pen.25280
SN - 1548-2634
VL - 60
IS - 2
SP - 267
EP - 280
PB - Wiley
AN - OPUS4-50285
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Turski Silva Diniz, Analice
A1 - Schartel, Bernhard
T1 - The effects of property variation on the dripping behaviour of polymers during UL94 test simulated by particle finite element method
N2 - The dripping behaviour of polymers is often observed experimentally through the UL94 flammability standard test. In this work, polymeric dripping under fire is investigated numerically using particle finite element method. A parametric analysis was carried out to observe the influence of a single property on overall dripping behaviour via a UL94 vertical test model. Surrogates and property ranges were defined for variation of the following parameters: glass transition temperature (Tg), melting temperature (Tm), decomposition temperature (Td), density (ρ), specific heat capacity (Cp), apparent effective heat of combustion of the volatiles, char yield (μ), thermal conductivity (k), and viscosity (η). Polyamide, poly(ether ether ketone), poly(methyl methacrylate), and polysulfone were used as benchmarks. Simulated results showed that specific heat capacity, thermal conductivity, and char yield allied with viscosity were the properties that most influenced dripping behaviour (starting time and occurrence).
KW - Dripping
KW - PFEM
KW - UL 94
KW - Simulation
KW - Fire behaviour
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597449
DO - https://doi.org/10.1515/epoly-2023-0194
SN - 1618-7229
VL - 24
IS - 1
PB - De Gruyter
AN - OPUS4-59744
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krebs, N.
A1 - Demleitner, M.
A1 - Albuquerque, R.Q.
A1 - Schartel, Bernhard
A1 - Ruckdäschel, H.
T1 - Bayesian Optimization of flame-retardant performance in a high-Tg epoxy resin system
N2 - Polymeric materials are widely used due to their mechanical properties and cost-effectiveness, but their inherent flammability requires effective flame-retardant additives to meet safety standards. Optimizing multicomponent flame-retardant formulations is challenging due to the vast experimental space. This study applies Bayesian Optimization (BO) to optimize flame-retardant formulations in high glass transition temperature (Tg) epoxy resins. Aluminum diethyl phosphinate (AlPi) was systematically combined with three synergists: zinc stannate (ZnSt), a silicone-based additive (DowSil), and low-melting glass frits (Ceepree). BO-guided experimental design expanded from 16 initial formulations to a total of 28, minimizing the Maximum Average Rate of Heat Emission (MARHE) under the constraint of Total Smoke Production (TSP) < 17 m2 using the epsilon-constraint method. BO revealed non-linear synergistic interactions: ZnSt significantly reduced smoke production while AlPi effectively lowered heat release. The optimized formulation (BO7) achieved the lowest MARHE (122 kW/m2) while maintaining acceptable smoke levels, establishing a new Pareto front. The results demonstrate the effectiveness of BO in accelerating the development of synergistic, halogen-free flame-retardant polymer systems, offering a scalable and sustainable approach to polymer formulation design.
KW - Machine learning
KW - Epoxy resin
KW - Bayesian optimization
KW - Flame retardancy
KW - Cone calorimeter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641070
DO - https://doi.org/10.1016/j.commatsci.2025.114210
SN - 0927-0256
SN - 1879-0801
VL - 260
SP - 1
EP - 9
PB - Elsevier
AN - OPUS4-64107
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Sproesser, G.
A1 - Schenker, S.
A1 - Pittner, Andreas
A1 - Borndörfer, R.
A1 - Rethmeier, Michael
A1 - Chang, Y.-J.
A1 - Finkbeiner, M.
T1 - Sustainable welding process selection based on weight space partitions
N2 - Selecting a welding process for a given application is crucial with respect to the sustainability of part manufacturing. Unfortunately, since welding processes are evaluated by a number of criteria, preferences for one or the other process can be contradictory. However, the prevalent procedure of weight assignment for each criterion is subjective and does not provide information about the entire solution space. From the perspective of a decision maker it is important to be able to assess the entire set of possible weightings and answer the question which welding process is optimal for which set of weights. This issue is investigated by means of a weight space partitioning approach. Two welding processes are considered with respect to three criteria that reflect their economic and environmental performance. In order to find the most sustainable welding process the underlying weight space partition is evaluated.
T2 - 13th Global Conference on Sustainable Manufacturing – Decoupling Growth from Resource Use
CY - Bình Dương New City, Vietnam
DA - 16.09.2015
KW - Welding costs
KW - Multi-criteria decision support
KW - LCA
KW - Welding process selection
KW - GMAW
KW - Multi-attribute decision method
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-353740
DO - https://doi.org/10.1016/j.procir.2016.01.077
SN - 2212-8271
VL - 40
SP - 127
EP - 132
PB - Elsevier B.V.
AN - OPUS4-35374
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Yang, Fan
A1 - Rethmeier, Michael
T1 - Toward prediction and insight of porosity formation in laser welding: A physics-informed deep learning framework
N2 - The laser welding process is an important manufacturing technology for metallic materials. However, its application is often hindered by the occurrence of porosity defects. By far, an accurate prediction of the porosity defects and an insight into its formation mechanism are still challenging due to the highly nonlinear physics involved. In this paper, we propose a physics-informed deep learning (PIDL) framework by utilizing mechanistic modeling and experimental data to predict the porosity level during laser beam welding of aluminum alloys. With a proper selection of the physical variables (features) concerning the solidification, liquid metal flow, keyhole stability, and weld pool geometry, the PIDL model shows great superiority in predicting the porosity ratio, with a reduction of mean square error by 41 %, in comparison with the conventional DL model trained with welding parameters. Furthermore, the selected variables are fused into dimensionless features with explicit physical meanings to improve the interpretability and extendibility of the PIDL model. Based on a well-trained PIDL model, the hierarchical importance of the physical variables/procedures on the porosity formation is for the first time revealed with the help of the Shapley Additive Explanations analysis. The keyhole ratio is identified as the most influential factor in the porosity formation, followed by the downward flow-driven drag force, which offers a valuable guideline for process optimization and porosity minimization.
KW - Laser beam welding
KW - Physics-informed deep learning
KW - Porosity prediction
KW - Feature fusion
KW - Hierarchical importance
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624708
DO - https://doi.org/10.1016/j.actamat.2025.120740
VL - 286
SP - 1
EP - 13
PB - Elsevier B.V.
AN - OPUS4-62470
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - Hirthammer, Volker
A1 - Rethmeier, Michael
T1 - Recommendations for an Open Science approach to welding process research data
N2 - The increasing adoption of Open Science principles has been a prevalent topic in the welding science community over the last years. Providing access to welding knowledge in the form of complex and complete datasets in addition to peer-reviewed publications can be identified as an important step to promote knowledge exchange and cooperation. There exist previous efforts on building data models specifically for fusion welding applications; however, a common agreed upon implementation that is used by the community is still lacking. One proven approach in other domains has been the use of an openly accessible and agreed upon file and data format used for archiving and sharing domain knowledge in the form of experimental data. Going into a similar direction, the welding community faces particular practical, technical, and also ideological challenges that are discussed in this paper. Collaboratively building upon previous work with modern tools and platforms, the authors motivate, propose, and outline the use of a common file format specifically tailored to the needs of the welding research community as a complement to other already established Open Science practices. Successfully establishing a culture of openly accessible research data has the potential to significantly stimulate progress in welding research.
KW - Welding
KW - Research data management
KW - Open science
KW - Digitalization
KW - Weldx
KW - Open source
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529332
DO - https://doi.org/10.1007/s40194-021-01151-x
SN - 1878-6669
SN - 0043-2288
SP - 1
EP - 9
PB - Springer
CY - Heidelberg
AN - OPUS4-52933
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaurasia, Prashant Kumar
A1 - Fabry, Çağtay
A1 - Pittner, Andreas
A1 - De, Amitava
A1 - Rethmeier, Michael
T1 - Automated in situ monitoring and analysis of process signatures and build profiles during wire arc directed energy deposition
N2 - Wire arc directed energy deposition (DED-Arc) is an emerging metal additive manufacturing process to build near-net shaped metallic parts in a layer-by-layer with minimal material wastage. Automated in situ monitoring and fast-responsive analyses of process signatures and deposit profiles during DED-Arc are in ever demand to print dimensionally consistent parts and reduce post-deposition machining. A comprehensive experimental investigation is presented here involving real-time synchronous measurement of arc current, voltage, and the deposit profile using a novel multi-sensor monitoring framework integrated with the DED-Arc set-up. The recorded current–voltage transients are used to estimate the time-averaged arc power, and energy input in real time for an insight of the influence of wire feed rate and printing travel speed on the deposit characteristics. A unique attempt is made to represent the geometric profiles of the single-track deposits in a generalized mathematical form corresponding to a segmented ellipse, which has exhibited the minimum root-mean-square error of 0.03 mm. The dimensional inconsistency of multi-track deposits is evaluated quantitatively in terms of waviness using build profile monitoring and automated estimation, which is found to increase with an increase in step-over ratio and energy input. For the multi-track mild steel deposits, the suitable range of step-over ratio for the minimum surface waviness is observed to lie between 0.6 and 0.65. Collectively, the proposed framework of synchronized process monitoring and real-time analysis provides a pathway to achieve dimensionally consistent and defect-free parts, and highlights the potential for closed-loop control systems for a wider industrial application of DED-Arc.
KW - Additive Manufacturing
KW - Arc welding
KW - DED-arc
KW - Real-time monitoring and control
KW - Dimensional inconsistency
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642029
DO - https://doi.org/10.1007/s40964-025-01333-9
SN - 2363-9512
SP - 1
EP - 20
PB - Springer Science and Business Media LLC
CY - Cham
AN - OPUS4-64202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Marko, A.
A1 - Bähring, S.
A1 - Raute, J.
A1 - Biegler, M.
A1 - Rethmeier, Michael
T1 - Quality Prediction in Directed Energy Deposition Using Artificial Neural Networks Based on Process Signals
N2 - The Directed Energy Deposition process is used in a wide range of applications including the repair, coating or modification of existing structures and the additive manufacturing of individual parts. As the process is frequently applied in the aerospace industry, the requirements for quality assurance are extremely high. Therefore, more and more sensor systems are being implemented for process monitoring. To evaluate the generated data, suitable methods must be developed. A solution, in this context, was the application of artificial neural networks (ANNs). This article demonstrates how measurement data can be used as input data for ANNs. The measurement data were generated using a pyrometer, an emission spectrometer, a camera (Charge-Coupled Device) and a laser scanner. First, a concept for the extraction of relevant features from dynamic measurement data series was presented. The developed method was then applied to generate a data set for the
quality prediction of various geometries, including weld beads, coatings and cubes. The results were compared to ANNs trained with process parameters such as laser power, scan speed and powder mass flow. It was shown that the use of measurement data provides additional value. Neural networks trained with measurement data achieve significantly higher prediction accuracy, especially for more complex geometries.
KW - DED
KW - Artificial neural network
KW - Process monitoring
KW - Quality assurance
KW - Data preparation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547039
DO - https://doi.org/10.3390/app12083955
VL - 12
IS - 8
SP - 1
EP - 13
PB - MDPI
AN - OPUS4-54703
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Influence of the free surface reconstruction on the spatial laser energy distribution in high power laser beam welding modeling
N2 - An accurate and efficient description of the spatial distribution of laser energy is a crucial factor for the modeling of laser material processing, e.g., laser welding, laser cutting, or laser-based additive manufacturing. In this study, a 3D heat transfer and fluid flow model coupled with the volume-of-fluid algorithm for free surface tracking is developed for the simulation of molten pool dynamics in high-power laser beam welding. The underlying laser-material interactions, i.e., the multiple reflections and Fresnel absorption, are considered by a raytracing method. Two strategies of free surface reconstruction used in the ray-tracing method are investigated: a typical piecewise linear interface calculation (PLIC)-based method and a novel localized level-set method. The PLIC-based method is discrete, resulting in noncontinuous free surface reconstruction. In the localized level-set method, a continuous free surface is reconstructed, and, thus, the exact reflection points can be determined. The calculated spatial laser energy distribution and the corresponding molten pool dynamics from the two methods are analyzed and compared. The obtained numerical results are evaluated with experimental measurements to assure the validity of the proposed model. It is found that distinct patterns of the beam multiple reflections are obtained with the different free surface reconstructions, which shows significant influence not only on the molten pool behaviors but also on the localized keyhole dynamics.
KW - Laser beam welding
KW - Laser energy distribution
KW - Weld pool dynamics
KW - Ray teacing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-562429
DO - https://doi.org/10.2351/7.0000739
SN - 1042-346X
VL - 34
IS - 4
SP - 042023-1
EP - 042023-8
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-56242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Miliūtė, Aistė
A1 - Bustamante, Joana
A1 - Karafiludis, Stephanos
A1 - Zöllner, Moritz
A1 - Eddah, Mustapha
A1 - Emmerling, Franziska
A1 - Mieller, Björn
A1 - George, Janine
A1 - Stawski, Tomasz M.
T1 - Synthesis and phase purity of the negative thermal expansion material ZrV2O7
N2 - Synthesis of pure, homogeneous, and reproducible materials is key for the comprehensive understanding, design, and tailoring of material properties. In this study, we focus on the synthesis of ZrV2O7, a material known for its negative thermal expansion properties. We investigate the influence of solid-state and wet chemistry synthesis methods on the purity and homogeneity of ZrV2O7 samples. Our findings indicate that different synthesis methods significantly impact the material's characteristics. The solid-state reaction provided high-purity material through extended milling time and repeated calcination cycles, while the sol-gel reaction enabled a “near-atomic” level of mixing and, therefore, homogenous phase-pure ZrV2O7. We confirmed purity via X-ray diffraction and Raman spectroscopy, highlighting differences between phase-pure and multiphase ceramics. These analytical techniques allowed us to distinguish subtle differences in the structure of the material. Based on ab initio simulated phonon data, we were able to interpret the Raman spectra and visualise Raman active atom vibrations. We show that phase purity enables the unbiased characterisation of material properties such as negative thermal expansion.
KW - NTE
KW - Sol-gel
KW - Solid-state
KW - Ab-initio
KW - XRD
KW - Raman
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624013
DO - https://doi.org/10.1039/d4tc04095c
SN - 2050-7534
SP - 1
EP - 13
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-62401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CHAP
A1 - Sproesser, G.
A1 - Change, Y.-J.
A1 - Pittner, Andreas
A1 - Finkbeiner, M.
A1 - Rethmeier, Michael
ED - Stark, R.
ED - Bonvoisin, J.
ED - Seliger, G.
T1 - Sustainable technologies for thick metal plate welding
N2 - Welding is the most important joining technology. In the steel construction
industry, e.g. production of windmill sections, welding accounts for a
main part of the manufacturing costs and resource consumption. Moreover, social
issues attached to welding involve working in dangerous environments. This aspect
has unfortunately been neglected so far, in light of a predominant focus on economics
combined with a lack of suitable assessment methods. In this chapter,
exemplary welding processes are presented that reduce the environmental and
social impacts of thick metal plate welding. Social and environmental Life Cycle
Assessments for a thick metal plate joint are conducted for the purpose of
expressing and analysing the social and environmental impacts of welding.
Furthermore, it is shown that state-of-the-art technologies like Gas Metal Arc
Welding with modified spray arcs and Laser Arc-Hybrid Welding serve to increase
social and environmental performance in contrast to common technologies, and
therefore offer great potential for sustainable manufacturing.
KW - Human health G.
KW - Life cycle assessment (LCA)
KW - Arc welding
KW - Laser arc-hybrid welding
KW - Resource efficiency
KW - Social life cycle assessment (SLCA)
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390025
SN - 978-3-319-48513-3
SN - 978-3-319-48514-0
DO - https://doi.org/10.1007/978-3-319-48514-0
SN - 2194-0541
SN - 2194-055X
SP - 71
EP - 84
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-39002
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Parametric study of the laser energy absorption in high-power laser beam welding
N2 - Laser energy absorption on the keyhole wall is decisive for the thermodynamic behavior and the resultant weld properties in the high-power laser beam welding process. However, its highly transient nature on a microsecond scale makes the quantitative analysis challenging. In this paper, the influence of the relevant welding parameters on laser energy absorption is studied statistically by utilizing multiphysical modeling, in which the three-dimensional transient keyhole dynamics and thermo-fluid flow are calculated. A dynamic mesh adaption technique and a localized level-set-based ray-tracing method are employed to improve the model accuracy further. The results show that the focus position has a remarkable effect on the time-averaged laser absorption, and in contrast, the laser energy distribution regime is only slightly influenced by the welding speed in the studied parameter range (1.5–3.0 m/min). The absorption ratio of the laser energy on the keyhole front wall decreases with increasing welding speed and increases with upward-moving focus positions. The comparison between the calculated results and the experimental measurements ensures the validity of the proposed model.
T2 - International Congress of Applications of Lasers & Electro-Optics 2024
CY - Los Angeles, CA, USA
DA - 03.11.2024
KW - Laser beam welding
KW - Laser energy absorption
KW - Weld pool
KW - Parametric study
KW - Multiphysics modeling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616070
DO - https://doi.org/10.2351/7.0001537
SN - 1042-346X
VL - 36
IS - 3
SP - 1
EP - 6
PB - AIP Publishing
AN - OPUS4-61607
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bevilacqua, Tommaso
A1 - Gumenyuk, Andrey
A1 - Habibi, Niloufar
A1 - Hartwig, Philipp
A1 - Klawonn, Axel
A1 - Lanser, Martin
A1 - Rethmeier, Michael
A1 - Scheunemann, Lisa
A1 - Schröder, Jörg
T1 - Large-scale thermo-mechanical simulation of laser beam welding using high-performance computing: A qualitative reproduction of experimental results
N2 - Laser beam welding (LBW) is a non-contact joining technique that has gained significant importance in modern industrial manufacturing. One potential problem, however, is the formation of solidification cracks, which particularly affects alloys with a pronounced melting range. The aim of the present work is the development of computational methods and software tools to numerically simulate LBW. In order to obtain a sufficiently accurate solution, a large number of finite elements has to be used. Therefore, a highly parallel scalable solver framework, based on the software library PETSc, was used to solve this computationally challenging problem on a high-performance computing architecture. Finally, the experimental results and the numerical simulations are compared. They are found to be in good qualitative agreement, which confirms the validity of the numerical simulations and allows for a better interpretation of the experimentally observed strain distribution.
KW - Laser beam welding
KW - Thermo-mechanical processes
KW - Solidification cracking
KW - High-performance computing
KW - Domain decomposition methods
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652902
DO - https://doi.org/10.1016/j.rineng.2025.108827
SN - 2590-1230
VL - 29
SP - 1
EP - 11
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65290
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Phase-field simulation of the dendrite fragmentation by electromagnetic stirring in AA5754 aluminum alloy laser beam welding
N2 - A phase-field model including magnetic field induced dendrite fragmentation was established and applied to the cases with different initial crystal nuclear positions for AA5754 aluminum alloy electromagnetic laser beam welding. Compare the calculated results that include dendrite fragmentation caused by the thermal electromagnetic Lorentz force with the results that consider only the thermal electromagnetic Lorentz force, without fragmentation, at the characteristic time instants. Both in the early and late stages, the small fragmentation at the dendrite tip promotes the number of higher-order branches and their growth, especially in the direction perpendicular to the solidification. The later stage fragmentation has the possibility of breaking one grain into several, which verifies the possibility of grain refinement caused by dendrite fragmentation. The fracture surface caused by fragmentation also makes more solid-liquid interfaces and their growth. In addition, the cases with different initial nuclear positions were compared. The grain growth in the low-temperature zone can be inhibited by the equiaxed grains' fragmentation at the high-temperature area (179.8 μm² and 14.7 % start at the center, 115.4 μm² and 9.4 % start at the high-temperature corner, 134.3 μm² and 10.9 % start at the low-temperature corner), which is another kind of grain refinement by the dendrite fragmentation. This kind of inhibition effect on grain growth in the low-temperature region will be enhanced with the increasing time interval between the two crystal nuclei’ appearance (179.8 μm² and 14.7 % when virtual grains appear at t = 4.3803 s and t = 4.3803 s, 134.3 μm² and 10.9 % at t = 4.0977 s and t = 3.9564 s, and 115.4 μm² and 9.4 % at t = 3.8151 s and t = 3.5325 s).
KW - Laser beam welding
KW - Electromagnetic
KW - Aluminum alloys
KW - Phase field method
KW - Equiaxed grain
KW - Dendrite fragmentation
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656610
DO - https://doi.org/10.1016/j.cwe.2025.100014
SN - 3117-4159
VL - 35
IS - 1
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-65661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Artinov, Antoni
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical analysis of the effect of an oscillating metal vapor plume on the keyhole and molten pool behavior during deep penetration laser beam welding
N2 - The effect of the oscillating metal vapor plume on the keyhole and molten pool behavior during the laser beam welding of AlMg3 aluminum alloys is investigated by experimental and numerical methods. The real-time height of the metal vapor plume is measured by high-speed camera observation. The obtained experimental results are used to evaluate the additional heating source and laser beam attenuation caused by the scattering and absorption based on the Beer–Lambert theory. Furthermore, the dynamic behavior of the metal vapor plume is incorporated into a 3D transient heat transfer and fluid flow model, coupled with the ray tracing method, for the laser beam welding of the AlMg3 alloy. It is found that additional heating resulting from the scattered and absorbed laser beam energy by the metal vapor plume significantly expands the shape of the molten pool on the top region. Moreover, the oscillating metal vapor plume caused the fluctuation of the high-temperature region in the molten pool. The probability of keyhole collapse at the bottom increases 17% due to the oscillating laser power induced by the laser beam attenuation. The internal interplay between the metal vapor plume, molten pool shape, and keyhole collapse is obtained. The developed model has been validated by experiments, which shows a good agreement.
T2 - International Congress of Applications of Lasers & Electro-Optics 2023
CY - Chicago, IL, USA
DA - 16.10.2023
KW - Deep penetration laser beam welding
KW - Numerical simulation
KW - Oscillating vapor plume
KW - Keyhole collapse
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-587978
DO - https://doi.org/10.2351/7.0001094
SN - 1938-1387
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
PB - AIP Publishing
CY - Melville, NY
AN - OPUS4-58797
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Axel
A1 - Goedecke, Caroline
A1 - Eisentraut, Paul
A1 - Piechotta, Christian
A1 - Braun, Ulrike
T1 - Microplastic analysis using chemical extraction followed by LC‑UV analysis: a straightforward approach to determine PET content in environmental samples
N2 - Background: The ubiquitous occurrence of microplastic particles in marine and aquatic ecosystems was intensively investigated in the past decade. However, we know less about the presence, fate, and input paths of microplastic in terrestrial ecosystems. A possible entry path for microplastic into terrestrial ecosystems is the agricultural application of sewage sludge and solid bio-waste as fertilizers. Microplastic contained in sewage sludge also includes Polyethylene terephthalate (PET), which could originate as fiber from textile products or as a fragment from packaging products (foils, bottles, etc.). Information about microplastic content in such environmental samples is limited yet, as most of the used analytical methods are very time-consuming, regarding sample preparation and detection, require sophisticated analytical tools and eventually need high user knowledge.
Results: Here, we present a simple, specific tool for the analysis of PET microplastic particles based on alkaline extraction of PET from the environmental matrix and subsequent determination of the monomers, terephthalic acid, using liquid chromatography with UV detection (LC-UV). The applicability of the method is shown for different types of PET in several soil-related, terrestrial environmental samples, e.g., soil, sediment, compost, fermentation residues, but also sewage sludge, suspended particles from urban water management systems, and indoor dust. Recoveries for model samples are between 94.5 and 107.1%. Limit of determination and limit of quantification are absolute masses of 0.031 and 0.121 mg PET, respectively. In order to verify the measured mass contents of the environmental samples, a method comparison with thermal extraction-desorption-gas chromatography–mass spectrometry (TED-GC/MS) was conducted. Both methods deliver similar results and corroborated each other. PET mass contents in environmental samples range from values below LOQ in agriculture soil up to 57,000 mg kg−1 in dust samples.
Conclusions: We demonstrate the potential of an integral method based on chemical extraction for the Determination of PET mass contents in solid environmental samples. The method was successfully applied to various matrices and may serve as an analytical tool for further investigations of PET-based microplastic in terrestrial ecosystems.
KW - Soil
KW - Analysis
KW - Microplastic
KW - PET
KW - LC-UV
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509060
DO - https://doi.org/10.1186/s12302-020-00358-x
IS - 32
SP - 85
PB - Springer Open
CY - Berlin
AN - OPUS4-50906
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Protasov, E
A1 - Noah, J O
A1 - Kästle Silva, J O
A1 - Mies, U S
A1 - Hervé, V
A1 - Dietrich, C
A1 - Lang, K
A1 - Mikulski, L
A1 - Platt, K
A1 - Poehlein, A
A1 - Köhler-Ramm, T
A1 - Miambi, E
A1 - Boga, H I
A1 - Feldewert, C
A1 - Ngugi, G K
A1 - Plarre, Rüdiger
A1 - Sillam-Dussès, D
A1 - Šobotník, J
A1 - Daniel, R
A1 - Brune, A
T1 - Diversity and taxonomic revision of methanogens and other archaea in the intestinal tract of terrestrial arthropods
N2 - Methane emission by terrestrial invertebrates is restricted to millipedes, termites, cockroaches, and scarab beetles. The arthropod-associated archaea known to date belong to the orders Methanobacteriales, Methanomassiliicoccales, Methanomicrobiales, and Methanosarcinales, and in a few cases also to nonmethanogenic Nitrososphaerales and Bathyarchaeales. However, all major host groups are severely undersampled, and the taxonomy of existing lineages is not well developed. Full-length 16S rRNA gene sequences and genomes of arthropod-associated archaea are scarce, reference databases lack resolution, and the names of many taxa are either not validly published or under-classified and require revision. Here, we investigated the diversity of archaea in a wide range of methane-emitting arthropods, combining phylogenomic analysis of isolates and metagenome-assembled genomes (MAGs) with amplicon sequencing of full-length 16S rRNA genes. Our results allowed us to describe numerous new species in hitherto undescribed taxa among the orders Methanobacteriales (Methanacia, Methanarmilla, Methanobaculum, Methanobinarius, Methanocatella, Methanoflexus, Methanorudis, and Methanovirga, all gen. nova), Methanomicrobiales (Methanofilum and Methanorbis, both gen. nova), Methanosarcinales (Methanofrustulum and Methanolapillus, both gen. nova), Methanomassiliicoccales (Methanomethylophilaceae fam. nov., Methanarcanum, Methanogranum, Methanomethylophilus, Methanomicula, Methanoplasma, Methanoprimaticola, all gen. nova), and the new family Bathycorpusculaceae (Bathycorpusculum gen. nov.). Reclassification of amplicon libraries from this and previous studies using this new taxonomic framework revealed that arthropods harbor only CO2 and methyl-reducing hydrogenotrophic methanogens.
Numerous genus-level lineages appear to be present exclusively in arthropods,suggesting long evolutionary trajectories with their termite, cockroach, and millipede hosts, and a radiation into various microhabitats and ecological nichesprovided by their digestive tracts (e.g., hindgut compartments, gut wall, or anaerobic protists). The distribution patterns among the different host groups are often complex, indicating a mixed mode of transmission and a parallel evolution of invertebrate and vertebrate-associated lineages.
KW - Nitrososphaerales
KW - Archaea
KW - Methanogens
KW - Gut microbiota
KW - Termites
KW - Cockroaches
KW - Millipedes
KW - Bathyarchaeia
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588230
DO - https://doi.org/10.3389/fmicb.2023.1281628
SN - 1664-302X
VL - 14
SP - 1
EP - 21
PB - Frontiers
AN - OPUS4-58823
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Palmer, Tahlia M.
A1 - Al-Sabbagh, Dominik
A1 - May, Anastasia
A1 - Prinz, Carsten
A1 - Michalik, Stefan
A1 - Michalchuk, Adam
A1 - Emmerling, Franziska
T1 - Pre‐Activation as a Route for Tuning the Kinetics of Mechanochemical Transformations
N2 - Learning to control reaction kinetics is essential for translating any chemical technology into real‐world application. Based on time‐resolved in situ powder X‐ray diffraction data, we demonstrate the opportunity to tune mechanochemical reaction rates through the pre‐activation of the starting reagents. For three model co‐crystal systems, the pre‐activation of the most stable reagent yields up to a ca 10‐fold increase in the reaction rate, whilst negligible kinetic enhancement is seen when the less stable reagent is pre‐activated. Moreover, we demonstrate how the polymorphic outcome of mechano‐co‐crystallization is also sensitive to pre‐activation of the starting material. Our results suggest that reproducibility of mechanochemical processes requires detailed understanding over the origin and history of reagent powders, whilst providing a new conceptual framework to design and control mechanochemical reactions.
KW - Mechanochemistry
KW - In situ synthesis
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649409
DO - https://doi.org/10.1002/anie.202516632
SN - 1433-7851
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-64940
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernges, T.
A1 - Hanus, R.
A1 - Wankmiller, B.
A1 - Imasato, K.
A1 - Lin, S.
A1 - Ghidiu, M.
A1 - Gerlitz, M.
A1 - Peterlechner, M.
A1 - Graham, S.
A1 - Hautier, G.
A1 - Pei, Y.
A1 - Hansen, M. R.
A1 - Wilde, G.
A1 - Snyder, G. J.
A1 - George, Janine
A1 - Agne, M T.
A1 - Zeier, W. G.
T1 - Considering the Role of Ion Transport in Diffuson-Dominated Thermal Conductivity
N2 - Next-generation thermal management requires the development of low lattice thermal conductivity materials, as observed in ionic conductors. For example, thermoelectric efficiency is increased when thermal conductivity is decreased. Detrimentally, high ionic conductivity leads to thermoelectric device degradation. Battery safety and design also require an understanding of thermal transport in ionic conductors. Ion mobility, structural complexity, and anharmonicity have been used to explain the thermal transport properties of ionic conductors. However, thermal and ionic transport are rarely discussed in direct comparison. Herein, the ionic conductivity of Ag+ argyrodites is found to change by orders of magnitude without altering the thermal conductivity. Thermal conductivity measurements and two-channel lattice dynamics modeling reveal that the majority of Ag+ vibrations have a non-propagating diffuson-like character, similar to amorphous materials. It is found that high ionic mobility is not a requirement for diffuson-mediated transport. Instead, the same bonding and structural traits that can lead to fast ionic conduction also lead to diffuson-mediated transport. Bridging the fields of solid-state ionics and thermal transport, it is proposed that a vibrational perspective can lead to new design strategies for functional ionic conducting materials. As a first step, the authors relate the so-called Meyer-Neldel behavior in ionic conductors to phonon occupations.
KW - Diffusons
KW - DFT
KW - Phonons
KW - Thermoelectrics
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547140
DO - https://doi.org/10.1002/aenm.202200717
SN - 1614-6832
VL - 12
IS - 22
SP - 1
EP - 13
PB - Wiley VHC-Verlag
AN - OPUS4-54714
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Artinov, Antoni
A1 - Meng, Xiangmeng
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Study on the transition behavior of the bulging effect during deep penetration laser beam welding
N2 - The present work is devoted to the study of the transition behavior of the recently confirmed widening of the weld pool, known as the bulging effect, during high-power deep penetration laser beam welding of thick unalloyed steel sheets. A three-dimensional transient multi-physics numerical model is developed, allowing for the prediction of the bulge formation and the study of its temporal behavior. The model is generalized to account automatically for the transition from partial to complete penetration. Several experimental measurements and observations, such as drilling period, weld pool length, temperature, efficiency, and metallographic cross-sections are used to verify the model and assure the plausibility of the numerical results. The analysis of the calculated temperature and velocity distributions, as well as the evolution of the keyhole geometry, shows that the formation of a bulging region strongly depends on the penetration depth of the weld. Based on the numerical results, the bulge is found to occur transiently, having its transition from a slight bulge to a fully developed bulging between penetration depths of 6 mm and 9 mm, respectively.
KW - Laser beam welding
KW - Deep penetration
KW - Bulge formation
KW - Numerical modeling
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545067
DO - https://doi.org/10.1016/j.ijheatmasstransfer.2021.122171
VL - 184
SP - 122171
PB - Elsevier Ltd.
AN - OPUS4-54506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - George, Janine
A1 - Petretto, G.
A1 - Naik, Aakash
A1 - Esters, M.
A1 - Jackson, A. J.
A1 - Nelson, R.
A1 - Dronskowski, R.
A1 - Rignanese, G.-M.
A1 - Hautier, G.
T1 - Automated bonding analysis with crystal orbital Hamilton populuations
N2 - Automated bonding analysis software has been developed based on Crystal Orbital Hamilton Populations to facilitate high-throughput bonding analysis and machine-learning of bonding features. This work presents the software and discusses its applications to simple and complex materials such as GaN, NaCl, the oxynitrides XTaO2N (X=Ca, Ba, Sr) and Yb14Mn1Sb11.
KW - Chemical bonds
KW - Automation
KW - High-throughput
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551641
DO - https://doi.org/10.1002/cplu.202200123
SN - 2192-6506
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-55164
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Arnold, M.
A1 - Katzmann, J.
A1 - Naik, Aakash
A1 - Görne, A. L.
A1 - Härtling, Thomas
A1 - George, Janine
A1 - Schuster, C.
T1 - Investigations on electron beam irradiated rare-earth doped SrF2 for application as low fading dosimeter material: Evidence for and DFT simulation of a radiation-induced phase
N2 - A recent approach to measure electron radiation doses in the kGy range is the use of phosphors with an irradiation dose-dependent luminescence decay time. However, the applicability of the previously investigated material NaYF4:Yb3+,Er3+ is limited as it shows pronounced fading. Therefore, in this work, a modified SrF2 synthesis is presented that results in SrF2 nanoparticles codoped with Yb and either Er, Hm, or Tm. To assess their suitability as dosimeter material, dose response, as well as its degree of fading over 50 up to 140 days after irradiation were measured. Fading rates as small as 5% in SrF2:Er,Yb and 4% in SrF2:Ho,Yb were derived, which are comparable to established dosimeter materials. A combination of spectroscopy, diffraction and DFT calculations was used to elucidate the effect of irradiation, pointing towards the formation of a secondary phase of Yb2+ that we predict could be Yb2OF2. This irreversible formation of a secondary phase is considered to be the explanation for the low fading behavior in SrF2-based phosphors compared to NaYF4:Yb, Er, a highly attractive feature for electron beam dosimetry.
KW - DFT
KW - Structure prediction
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-554115
DO - https://doi.org/10.1039/D2TC01773C
SN - 2050-7526
VL - 10
IS - 32
SP - 11579
EP - 11587
PB - RSC
CY - London
AN - OPUS4-55411
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Straße, Anne
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Study on Duplex Stainless Steel Powder Compositions for the Coating of thick Plates of Laser Beam Welding
N2 - Duplex stainless steels combine the positive properties of its two phases, austenite and ferrite. Due to its good corrosion resistance, high tensile strength, and good ductility, it has multiple applications. But laser beam welding of duplex steels changes the balanced phase distribution in favor of ferrite. This results in a higher vulnerability to corrosion and a lower ductility. Herein, different powder combinations consisting of duplex and nickel for coating layers by laser metal deposition (LMD) are investigated. Afterward, laser tracks are welded, and the temperature cycles are measured. The ferrite content of the tracks is analyzed by feritscope, metallographic analysis, and electron backscatter diffraction. The goal is the development of a powder mixture allowing for a duplex microstructure in a two-step process, where first the edges of the weld partners are coated with the powder mixture by LMD and second those edges are laser beam welded. The powder mixture identified by the pretests is tested in the two-step process and analyzed by metallographic analysis, energy-dispersive X-ray spectroscopy, and
Vickers hardness tests. The resulting weld seams show a balanced duplex microstructure with a homogenous nickel distribution and a hardness of the weld seam similar to the base material.
KW - Duplex AISI 2205
KW - Laser metal deposition
KW - Laser beam welding
KW - Nickel
KW - Stainless steels
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547024
DO - https://doi.org/10.1002/adem.202101327
SN - 1438-1656
SP - 1
EP - 11
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-54702
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mosquera Feijoo, Maria
A1 - Oder, Gabriele
A1 - Saliwan Neumann, Romeo
A1 - Buchheim, Michaela
A1 - Kranzmann, Axel
A1 - Olbricht, Jürgen
T1 - Impact of Sample Geometry and Surface Finish on VM12‑SHC Ferritic–Martensitic Steel Under Cyclic Steam Atmosphere Operating Conditions
N2 - The steam side oxidation of ferritic–martensitic VM12-SHC steel was investigated under thermo-cyclic conditions in water steam at 620/320 °C and 30 bar with a focus on assessing the influence of pre-oxidation time, specimen geometry and surface finish. The specimens were pre-oxidized under isothermal conditions in water steam at 620 °C and 30 bar for 500 h or 1500 h. After pre-oxidation treatment, all specimens were subjected up to 258 thermal cycles. Three different geometries—rectangular coupons, U-shaped ring segments and ring samples—were investigated to evaluate the influence of open/closed shape, and flat/curved surface on corrosion rate. At the same time, two types of surface finish were considered: “as received” and “ground.” The formation of a protective scale by pre-oxidation was investigated. EBSD and ESMA analyses revealed that the Cr-content of the alloy appeared to be insufficient for obtaining a protective oxide scale under studied conditions, at the same time the anayses confirmed that initial oxidation depends on presence of minor alloying elements as Si and Mn, strong oxide formers which can alter the kinetics and morphology of the corrosion reaction. Moreover, rectangular coupons with small wall thickness and flat surface exhibited the highest corrosion rate, while “ground” curved samples showed only local oxidation. This indicates that for same pre-oxidation time, oxidation kinetics is controlled by curvature.
KW - Cyclic steam oxidation
KW - 12%Cr steel
KW - Specimen geometry
KW - Surface treatments
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551808
DO - https://doi.org/10.1007/s11085-022-10114-6
SN - 0030-770X
SP - 1
EP - 18
PB - Springer
AN - OPUS4-55180
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geisen, O.
A1 - Müller, V.
A1 - Graf, B.
A1 - Rethmeier, Michael
T1 - Integrated weld preparation designs for the joining of L‑PBF and conventional components via TIG welding
N2 - size limitations and high production costs of L-PBF make it competitive for smaller, highly complex components, while the less complex elements of an assembly are manufactured conventionally. This leads to scenarios that use L-PBF only where it’s beneficial, and it require an integration and joining to form the final product. For example, L-PBF combustion swirlers are welded onto cast parts to produce combustion systems for stationary gas turbines. Today, the welding process requires complex welding fixtures and tack welds to ensure the correct alignment and positioning of the parts for repeatable weld results. In this paper, L-PBF and milled weld preparations are presented as a way to simplify the Tungsten inert gas (TIG) welding of rotationally symmetrical geometries using integrated features for alignment and fixation. Pipe specimens with the proposed designs are manufactured in Inconel 625 using L-PBF and milling. The pipe assembly is tested and TIG welding is performed for validation. 3D scans of the pipes before and after welding are evaluated, and the weld quality is examined via metallography and computed tomography (CT) scans. All welds produced in this study passed the highest evaluation group B according to DIN 5817. Thanks to good component alignment, safe handling, and a stable welding process, the developed designs eliminate the need for part-specific fixtures, simplify the process chain, and increase the process reliability. The results are applicable to a wide range of components with similar requirements.
KW - L-PBF
KW - AM feature integration
KW - TIG welding
KW - Integrated alignment features
KW - Pipe weld preparation
KW - Dissimilar joints
KW - Inconel 625
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-547042
DO - https://doi.org/10.1007/s40964-021-00221-2
SN - 2363-9512
SP - 1
EP - 11
PB - Springer
AN - OPUS4-54704
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Üstündag, Ömer
A1 - Bakir, Nasim
A1 - Gook, S.
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Hybrid laser‑arc welding of laser‑ and plasma‑cut 20‑mm‑thick structural steels
N2 - It is already known that the laser beam welding (LBW) or hybrid laser-arc welding (HLAW) processes are sensitive to manufacturing tolerances such as gaps and misalignment of the edges, especially at welding of thick-walled steels due to its narrow beam diameter. Therefore, the joining parts preferably have to be milled. The study deals with the influence of the edge quality, the gap and the misalignment of edges on the weld seam quality of hybrid laser-arc welded 20-mm-thick structural steel plates which were prepared by laser and plasma cutting. Single-pass welds were conducted in butt joint configuration. An AC magnet was used as a contactless backing. It was positioned under the workpiece during the welding process to prevent sagging. The profile of the edges and the gap between the workpieces were measured before welding by a profile scanner or a digital camera, respectively. With a laser beam power of just 13.7 kW, the single-pass welds could
be performed. A gap bridgeability up to 1 mm at laser-cut and 2 mm at plasma-cut samples could be reached respectively.
Furthermore, a misalignment of the edges up to 2 mm could be welded in a single pass. The new findings may eliminate the need for cost and time-consuming preparation of the edges.
KW - Hybrid laser-arc welding
KW - Thick-walled steel
KW - Edge quality
KW - Gap bridgeability
KW - Laser cutting
KW - Plasma cutting
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-552013
DO - https://doi.org/10.1007/s40194-022-01255-y
SN - 0043-2288
VL - 66
SP - 507
EP - 514
PB - Springer
AN - OPUS4-55201
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - El-Sari, Bassel
A1 - Olfert, Viktoria
A1 - Wang, Zhuoqun
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - Expulsion prevention in resistance spot welding of dissimilar joints with ultra-high strength steel: An analysis of the mechanism and effect of preheating current
N2 - The widespread adoption of ultra-high strength steels, due to their high bulk resistivity, intensifies expulsion issues in resistance spot welding (RSW), deteriorating both the spot weld and surface quality. This study presents a novel approach to prevent expulsion by employing a preheating current. Through characteristic analysis of joint formation under critical welding current, the importance of plastic material encapsulation around the weld nugget (plastic shell) at high temperatures in preventing expulsion is highlighted. To evaluate the effect of preheating on the plastic shell and understand its mechanism in expulsion prevention, a two-dimensional welding simulation model for dissimilar ultra-high strength steel joints was established. The results showed that optimal preheating enhances the thickness of the plastic shell, improving its ability to encapsulate the weld nugget during the primary welding phase, thereby diminishing expulsion risks. Experimental validation confirmed that by employing the optimal preheating current, the maximum nugget diameter was enhanced to 9.42 mm, marking an increase of 13.4 % and extending the weldable current range by 27.5 %. Under quasi-static cross-tensile loading, joints with preheating demonstrated a 7.9 % enhancement in maximum load-bearing capacity compared to joints without preheating, showing a reproducible and complete pull-out failure mode within the heat-affected zone. This study offers a prevention method based on underlying mechanisms, providing a new perspective for future research on welding parameter optimization with the aim of expulsion prevention.
KW - Resistance spot welding
KW - Finite element modelling
KW - Preheating
KW - Weldable current range
KW - Ultra-high strength steel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621719
DO - https://doi.org/10.1016/j.jmapro.2024.06.034
VL - 124
SP - 489
EP - 502
PB - Elsevier Ltd.
AN - OPUS4-62171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Uhlmann, Eckart
A1 - Polte, Julian
A1 - Fasselt, Janek Maria
A1 - Müller, Vinzenz
A1 - Klötzer-Freese, Christian
A1 - Kleba-Ehrhardt, Rafael
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - A Comparative Evaluation of Powder Characteristics of Recycled Material from Bronze Grinding Chips for Additive Manufacturing
N2 - In the manufacturing process of ship propellers, large quantities of grinding chips are generated. These grinding chips result from the finishing of the blade surfaces after the primary casting process of the propeller. The aim of this study was to investigate and compare different preparation processes used to produce chip powders with sufficient powder quality for the additive manufacturing process of directed energy deposition. The preparation of the samples was performed through different sieving, milling and re-melting processes. For the characterization of the prepared samples, powder analysis according to relevant industry standards was carried out. It was found that the re-melting processes result in superior powder quality for additive manufacturing in terms of particle size, morphology, and flowability. For some characteristics, the powder exhibits even better properties than those of commercial powders. Furthermore, the powder properties of the milled samples demonstrate a promising potential for u
KW - Grinding chips
KW - Comminution
KW - Aluminium bronze
KW - Additive manufacturing
KW - Recycling
KW - Sustainability
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621696
DO - https://doi.org/10.3390/ma17143396
VL - 17
IS - 14
SP - 1
EP - 15
PB - MDPI AG
AN - OPUS4-62169
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - Sowada, Matthias
A1 - Olfert, Viktoria
A1 - Seitz, Georg
A1 - Schreiber, Vincent
A1 - Heitmann, Marcel
A1 - Hein, David
A1 - Biegler, Max
A1 - Jüttner, Sven
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - Influence of liquid metal embrittlement on the failure behavior of dissimilar spot welds with advanced high-strength steel: A component study
N2 - This study investigates the effects of liquid metal embrittlement (LME) cracks on the mechanical performance of resistance spot-welded joints in zinc-coated advanced high-strength steel (AHSS) at the component level. To this end, a novel component-level test specimen featuring a hat and L-shaped profile was developed to identify
critical failure points under three-point bending loads. Load-bearing capacity tests were subsequently conducted under both quasi-static and impact loading conditions, specifically targeting LME cracks with an average depth reaching 63.6% of the sheet thickness. By monitoring the surface strain of spot welds affected by LME cracks, the study visualizes stress concentration effects at the crack tips and traces the propagation of these cracks into the base material, which ultimately leads to material tearing and joint failure. The findings reveal that the effect of LME cracks in reducing load-bearing capacity is more pronounced under impact loading than under quasi-static
loading, highlighting a previously underexplored aspect of LME behavior under impact loading. Specifically, the peak load decreased by 3.9% and 10.8%, while energy absorption declined by 52.2% and 78.3% under quasistatic and impact loading, respectively.
KW - Liquid metal embrittlement
KW - Resistance spot welding
KW - Impact loading
KW - Crack propagation
KW - Advanced high-strength steel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621727
DO - https://doi.org/10.1016/j.jmrt.2024.11.166
VL - 33
SP - 8321
EP - 8328
PB - Elsevier B.V.
AN - OPUS4-62172
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghosh, Sheuly
A1 - Ueltzen, Katharina
A1 - George, Janine
A1 - Neugebauer, Jörg
A1 - Körmann, Fritz
T1 - Chemical ordering and magnetism in face-centered cubic CrCoNi alloy
N2 - AbstractThe impact of magnetism on chemical ordering in face-centered cubic CrCoNi medium entropy alloy is studied by a combination of ab initio simulations, machine learning potentials, and Monte Carlo simulations. Large magnetic energies are revealed for some mixed L12/L10 type ordered configurations, which are rooted in strong nearest-neighbor magnetic exchange interactions and chemical bonding among the constituent elements. There is a delicate interplay between magnetism and stability of MoPt2 and L12/L10 type of order, which may explain opposing experimental and theoretical findings.
KW - Chemically complex materials
KW - Alloys
KW - Magnetism
KW - Bonding analysis
KW - Machine learning
KW - Machine-learned interatomic potentials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-623114
DO - https://doi.org/10.1038/s41524-024-01439-8
SN - 2057-3960
VL - 10
IS - 1
SP - 1
EP - 10
PB - Springer Science and Business Media LLC
AN - OPUS4-62311
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Raute, Julius
A1 - Beret, Alexander
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Life cycle assessment in additive manufacturing of copper alloys—comparison between laser and electron beam
N2 - Additive manufacturing is becoming increasingly important for industrial production. In this context, directed energy deposition processes are in demand to achieve high deposition rates. In addition to the well-known laser-based processes, the electron beam has also reached industrial market maturity. The wire electron beam additive manufacturing offers advantages in the processing of copper materials, for example. In the literature, the higher energy efficiency and the resulting improvement in the carbon footprint of the electron beam are highlighted. However, there is a lack of practical studies with measurement data to quantify the potential of the technology. In this work, a comparative life cycle assessment between wire electron beam additive manufacturing (DED-EB) and laser powder additive manufacturing (DED-LB) is carried out. This involves determining the resources for manufacturing, producing a test component using both processes, and measuring the entire energy consumption. The environmental impact is then estimated using the factors global warming potential (GWP100), photochemical ozone creation potential (POCP), acidification potential (AP), and eutrophication potential (EP). It can be seen that wire electron beam additive manufacturing is characterized by a significantly lower energy requirement. In addition, the use of wire ensures greater resource efficiency, which leads to overall better life cycle assessment results.
KW - Life cycle assessment (LCA)
KW - Additive manufacturing
KW - Directed energy deposition
KW - Wire electron beam additive manufacturing
KW - Copper alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621705
DO - https://doi.org/10.1007/s40194-024-01856-9
SP - 3169
EP - 3176
PB - Springer Science and Business Media LLC
AN - OPUS4-62170
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lemke, Josefine
A1 - Höfemann, Matthias
A1 - Biegler, Max
A1 - Rethmeier, Michael
T1 - Process strategies for optimizing the cooling behaviour of laser-welded Tailor Welded Blanks made of advanced high strength steels (AHSS)
N2 - AHSS with 1000 MPa tensile strength show promising properties for the use in Tailor Welded Blanks (TWBs) to locally strengthen car body parts. Challenges in laser beam welding of the sheets are hardness-drops and -peaks in the heat-affected zone (HAZ) and weld, which cause risks during cold-forming. This happens due to rapid cooling caused by laser welding. A numerical approach aiming for slower cooling rates in the weld region is presented in this article. Laser welded sheets served as reference for setting up a process simulation. Models for pre-heating and a coaxial setup with power split were set up. A correlation between cooling-rate and hardness in the joining zone was established and applied to the modelled strategy. Splitting the power led to a slightly narrower weld seam and experimental pre-heating of the sheets to 600 °C could lower total seam hardening. It achieved a homogenization of the fusion zone.
KW - AHSS
KW - Laser welding
KW - Tailor Welded Blanks
KW - Hardness
KW - FEM
KW - HAZ
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622324
DO - https://doi.org/10.1016/j.procir.2024.08.176
VL - 124
SP - 570
EP - 573
PB - Elsevier B.V.
AN - OPUS4-62232
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Putra, Stephen Nugraha
A1 - Meng, Xiangmeng
A1 - Yang, Fan
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Numerical study on the temperature characteristic of material absorptivity and its significance in high-power laser beam welding
N2 - The absorptivity of metallic materials plays an important role in high-power laser beam welding. It affects the amount of absorbed laser power leading to the heating and melting of the surfaces to be joined and is highly dependent on the temperature. Nonetheless, this key characteristic is often ignored in numerical simulations and an empirical parameter determined by trial-and-error approaches is rather implemented to calibrate the results. In the present work, the temperature dependence of laser absorption is included in a three-dimensional multiphase numerical model considering the coupled fluid flow and heat transfer. The calculated laser absorption is determined by the temperature-dependent material properties, laser characteristics, and incident angle of the laser beam. It is found that the temperature dependence of the laser absorption is crucial for accurately determining the keyhole and weld pool geometries, which is validated by experimental measurements using 304 austenitic steel.
T2 - 13th CIRP Conference on Photonic Technologies [LANE 2024]
CY - Fürth, Germany
DA - 15.09.2024
KW - Laser beam welding
KW - Temperature dependent absorption
KW - Weld pool
KW - Keyhole dynamics
KW - Numerical modelling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-616146
DO - https://doi.org/10.1016/j.procir.2024.08.179
VL - 124
SP - 585
EP - 589
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-61614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lima, G. T. S.
A1 - Silvestro, L.
A1 - Durlo Tambara, Luís Urbano
A1 - Cheriaf, M.
A1 - Rocha, J. C.
T1 - Autonomous Self-Healing Agents in Cementitious Materials: Parameters and Impacts on Mortar Properties
N2 - The concept of self-healing materials and the development of encapsulated curing agents represent a cutting-edge approach to enhancing the longevity and reducing the maintenance costs of cementitious structures. This systematic literature review aims to shed light on the parameters involved in the autonomous self-healing of cementitious materials, utilizing various encapsulated healing agents such as pellets, granules, and capsules. This review also identifies and selects studies that offer additional insights into the efficacy of the self-healing process in cementitious materials and the influence of these specific encapsulated healing agents on the physical mechanical properties of mortars. This comprehensive approach provides a deep understanding of the interplay between self-healing and the physical–mechanical properties of mortars containing these encapsulated healing agents. The main findings indicate that the cement-to-sand ratio, characteristics of fine aggregates, and encapsulation methods significantly impact crack control, self-healing efficiency, and properties of mortar in both fresh and hardened states. The content of encapsulated healing agents within the cementitious matrix affects both the initial workability or flow and subsequent mechanical properties. While pellets coated with PVA film typically reduce workability in the fresh state and compressive strength, capsules coated with Portland cement and sodium silicate mitigate these effects and improve crack sealing in fresh and hardened states without compromising the self-healing capacity of cracks. The three-point flexural test has emerged as the preferred method for a pre-crack assessment over 28 days, with variations depending on the type of healing agent used. As noted in the literature, water has been identified as the optimal environment for autonomous healing. These findings underscore the potential of encapsulation techniques to enhance self-healing capabilities through the controlled release of agents within the cementitious matrix, thereby advancing the research on and development of intelligent construction materials and increasing the durability of cement-based structures.
KW - Self-healing cementitious composite
KW - Encapsulated curing agents
KW - Pellets
KW - Granules
KW - Capsules
KW - Physical–mechanical properties
KW - Autonomous self-healing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-611860
DO - https://doi.org/10.3390/buildings14072000
SN - 2075-5309
VL - 14
IS - 7
SP - 1
EP - 23
PB - MDPI
CY - Basel
AN - OPUS4-61186
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Krause, Christina
A1 - Szymoniak, Paulina
A1 - Lohstroh, W.
A1 - Juranyi, F.
A1 - Zamponi, M.
A1 - Frick, B.
A1 - Al-Sabbagh, Dominik
A1 - Emmerling, Franziska
A1 - Zorn, R.
A1 - Schönhals, Andreas
T1 - Complex molecular dynamics of symmetric model discotic liquid crystals: Comparison of Hexakis(hepta-alkanoyloxy)triphenylene (HOT6) with Hexakis(hexa-alkyloxy)triphenylene (HAT6)
N2 - This study investigates the complex molecular dynamics of discotic liquid crystals (DLCs) by comparing two structurally similar compounds: Hexakis(hepta-alkanoyloxy)triphenylene (HOT6) and Hexakis(hexa-alkyloxy)triphenylene (HAT6) having the same triphenyl core and the same length of the alkyl side chain. The difference of both materials is that the alkyl chain is linked by an oxygen bridge to the triphenylene core for HAT6 and by a ester group for HOT6. Using a combination of broadband dielectric spectroscopy, differential scanning calorimetry, X-ray scattering, and neutron scattering techniques, the research explores the glass transition phenomena and relaxation processes in these materials. HOT6, featuring ester linkages, exhibits distinct dynamic behavior compared to HAT6, including two separate glass transitions indicated by the 1- and 2-relaxation found by dielectric spectroscopy which are assigned to the glassy dynamics of the alkyl side chain in the intercolumnar space and that of the columns, respectively. The study reveals that the ester group in HOT6 leads to increased molecular rigidity and altered packing in the intercolumnar space, as evidenced by X-ray scattering and the vibrational density of states. Neutron scattering confirms localized methyl group rotations and a further relaxation process which relates to the -relaxation revealed by dielectric spectroscopy. The findings contribute to a deeper understanding of glassy dynamics in partially ordered systems and highlight the influence of molecular architecture on relaxation behavior in DLCs.
KW - Discotic Liquid Crystals
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655171
DO - https://doi.org/10.1039/d5sm01247c
SN - 1744-6848
SP - 1
EP - 17
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-65517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Durlo Tambara, Luís Urbano
A1 - Hirsch, A.
A1 - Dehn, F.
A1 - Gluth, Gregor
T1 - Carbonation resistance of alkali-activated GGBFS/calcined clay concrete under natural and accelerated conditions
N2 - The carbonation resistance of alkali-activated materials (AAMs) is a crucial parameter for their applicability in concrete construction, yet the parameters influencing it are insufficiently understood to date. In the present study, the carbonation resistance of alkali-activated concretes with varying fractions of ground granulated blast furnace slag (GGBFS) and calcined clay (i.e., high, intermediate, and low Ca contents) were assessed under natural and accelerated conditions. Corresponding hardened AAM pastes were studied using X-ray diffraction, thermogravimetry, Raman microscopy, and mercury intrusion porosimetry. The carbonation resistance of the concretes at natural CO2 concentration depended principally on their water/(CaO + MgOeq + Na2Oeq + K2Oeq) ratio. The remaining variability for similar ratios was caused by differences between the pore structures of the AAMs. For concrete with favorable water/(CaO + MgOeq + Na2Oeq + K2Oeq) ratio and pore structure, the carbonation resistance was comparable to that of Portland cement concrete. The relationship between carbonation coefficients obtained under accelerated and natural conditions differed for concretes with high and low fractions of calcined clay, indicating that accelerated carbonation testing is less suitable to study the carbonation of low-Ca AAMs.
KW - Alkali-activated materials
KW - Carbonation
KW - Calcined clay
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610747
DO - https://doi.org/10.1016/j.conbuildmat.2024.138351
SN - 1879-0526
VL - 449
SP - 1
EP - 14
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61074
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pérez Blanes, H.
A1 - Ghiasi, Pouria
A1 - Sandkühler, J.
A1 - Yesilcicek, Yasemin
A1 - Pentzien, Simone
A1 - Conradi, Andrea
A1 - Prinz, Carsten
A1 - Al-Sabbagh, Dominik
A1 - Thünemann, Andreas
A1 - Özcan Sandikcioglu, Özlem
A1 - Witt, Julia
T1 - High CO2 reduction activity on AlCrCoCuFeNi multi-principal element alloy nanoparticle electrocatalysts prepared by means of pulsed laser ablation
N2 - Noble metal-free nanoparticles (NPs) based on multi-principal element alloys (MPEAs) were synthesized using a one-step pulsed laser ablation in liquids (PLALs) method for the electrochemical reduction of CO2. Laser ablation was performed in pure water or poly-(diallyldimethylammonium chloride) (PDADMAC)-containing an aqueous solution of Al8Cr17Co17Cu8Fe17Ni33 MPEA targets. Transmission electron microscopy (TEM) measurements combined with energy dispersive X-ray (EDX) mapping were used to characterize the structure and composition of the laser-generated MPEA nanoparticles (MPEA-NPs). These results confirmed the presence of a characteristic elemental distribution of a core-shell phase structure as the predominant NP species. The electrocatalytic performance of the laser-generated MPEA-NPs was characterized by linear sweep voltammetry (LSV) demonstrating an enhanced electrocatalytic CO2 activity for PDADMAC-stabilized NPs. The findings of these investigations indicate that MPEAs have great potential to replace conventional, expensive noble metal electrocatalysts.
KW - Metals and Alloys
KW - Surfaces
KW - Biomaterials
KW - Ceramics and Composites
KW - Coatings and Films
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588218
DO - https://doi.org/10.1016/j.jmrt.2023.05.143
SN - 2238-7854
VL - 24
SP - 9434
EP - 9440
PB - Elsevier B.V.
AN - OPUS4-58821
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tambara, R. F.
A1 - Durlo Tambara, Luís Urbano
A1 - Venquiaruto, S. D.
A1 - Pereira da Costa, F. B.
T1 - Evaluation of the mechanical performance and capillary absorption of concretes with incorporation of crystallizing admixtures and subjected to damage at early ages
T1 - Avaliação do desempenho mecânico e absorção capilar de concretos com incorporação de aditivos cristalizante submetidos a danos nas primeiras idades
N2 - This study assessed the self-healing phenomenon in the mechanical properties and capillary absorption of structural concretes. Two crystalline powder additives were evaluated, dosed according to the manufacturers’ recommendations. Crystalline additives increase the density of the C-S-H gel and form insoluble crystals, effectively blocking fissures. Three concrete mixes were produced: a reference mix, additive-X with 0.8%, and additive-Y with 2.0%, relative to the mass of cement. 75% of the rupture load was applied at 3- and 14-days to induce microfissures for comparison with the reference mix. Subsequently, self-healing was assessed at 28- and 76-days. The property of axial compressive strength was determined at 28-days, revealing that crystalline additives contributed to an average increase of 12% in this property. While the age of loading did not significantly impact axial compressive strength, there were significant variations among the types of additives studied, as indicated by ANOVA. Water absorption properties through capillarity were evaluated at 28- and 76-days, showing an average reduction of 42% in water absorption due to the use of crystalline additives. In conclusion, the inclusion of crystalline additives positively contributed to the self-healing of the studied concretes, suggesting a partial recovery of microfissures.
N2 - Esta pesquisa avaliou o fenômeno de autocicatrização nas propriedades mecânicas e absorção capilar de concretos estruturais. Foram avaliados dois aditivos cristalizantes em pó, dosados de acordo com o teor recomendado pelos fabricantes. Aditivos cristalizantes aumentam a densidade do gel C-S-H e formam cristais insolúveis, bloqueando fissuras. Três traços de concreto foram produzidos: referência, aditivo-X com 0,8% e aditivo-Y com 2,0% em relação a massa do cimento. Aplicou-se 75% da carga de ruptura aos 3- e 14-dias para gerar microfissuras e comparar com a referência. Posteriormente, a autocicatrização foi avaliada aos 28- e 76-dias. A propriedade de resistência à compressão axial foi determinada aos 28-dias, revelando que os aditivos cristalizantes contribuíram para um aumento médio de 12% desta propriedade. A idade do carregamento dos concretos não apresentou um impacto significativo na resistência à compressão axial, mas apontou resultados significativos entre os tipos de aditivos estudados, conforme ANOVA. As propriedades de absorção de água por capilaridade foram avaliadas aos 28- e 76-dias, indicando uma redução de absorção de água média de 42% devido ao uso dos aditivos cristalizantes. Em conclusão, a incorporação dos aditivos cristalizantes contribuiu de maneira positiva para a autocicatrização dos concretos estudados, indicando uma recuperação parcial das microfissuras.
KW - Self-healing
KW - Crystalline admixture
KW - Concrete
KW - Cracks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599140
DO - https://doi.org/10.1590/1517-7076-RMAT-2023-0355
SN - 1517-7076
VL - 29
IS - 1
SP - 1
EP - 20
CY - Rio de Janeiro
AN - OPUS4-59914
LA - por
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Durlo Tambara, Luís Urbano
A1 - Nikoonasab, Ali
A1 - Radtke, Martin
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Gluth, Gregor
T1 - Determination of the oxidation depths of ground granulated blast furnace slag-containing cement pastes using Mn K-edge X-ray absorption near-edge structure spectroscopy
N2 - The redox potential of the pore solution of hardened cements containing ground granulated blast furnace slag (GGBFS) affects reinforcement corrosion and immobilization of radioactive waste. Here, Mn K-edge X-ray absorption near-edge structure (XANES) spectroscopy was applied to determine the depth profile of the oxidation state of manganese in hardened GGBFS-containing cement pastes. Manganese was oxidized in the outer regions of some of the pastes, but the depth to which this occurred was not identical with the ‘blue-green/white color change front’, usually interpreted as indicating oxidation of sulfur species. For CEM III/B, the color change of the material was gradual and thus unsuitable for a precise determination of the oxidation depth, while for the alkali-activated slag, a distinct color change front was found, but full oxidation of manganese and sulfur had not occurred in the brighter region. Mn K-edge XANES spectroscopy is thus a more reliable method than the determination of the visual color change front to follow the ingress of the oxidation front.
KW - Manganese
KW - Oxidation
KW - Sulfide
KW - Alkali-activated materials
KW - Redox conditions
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-651469
DO - https://doi.org/10.1111/jace.70445
SN - 0002-7820
SN - 1551-2916
VL - 109
IS - 1
SP - 1
EP - 11
PB - Wiley
CY - Oxford
AN - OPUS4-65146
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Starkholm, A.
A1 - Al-Sabbagh, Dominik
A1 - Sarisozen, S
A1 - von Reppert, A
A1 - Rössle, M
A1 - Ostermann, Markus
A1 - Unger, E
A1 - Emmerling, Franziska
A1 - Kloo, L
A1 - Svensson, P
A1 - Lang, F
A1 - Maslyanchuk, O.
T1 - Green Fabrication of Sulfonium-Containing Bismuth Materials for High-Sensitivity X-Ray Detection
N2 - Organic–inorganic hybrid materials based on lead and bismuth have recently been proposed as novel X- and gamma-ray detectors for medical imaging, non-destructive testing, and security, due to their high atomic numbers and facile preparation compared to traditional materials like amorphous selenium and Cd(Zn)Te. However, challenges related to device operation, excessively high dark currents, and long-term stability have delayed commercialization. Here, two novel semiconductors incorporating stable sulfonium cations are presented, [(CH3CH2)3S]6Bi8I30 and [(CH3CH2)3S]AgBiI5, synthesized via solvent-free ball milling and fabricated into dense polycrystalline pellets using cold isostatic compression, two techniques that can easily be upscaled, for X-ray detection application. The fabricated detectors exhibit exceptional sensitivities (14 100–15 190 µC Gyair−1 cm−2) and low detection limits (90 nGyair s−1 for [(CH3CH2)3S]6Bi8I30 and 78 nGyair s−1 for [(CH3CH2)3S]AgBiI5), far surpassing current commercial detectors. Notably, they maintain performance after 9 months of ambient storage. The findings highlight [(CH3CH2)3S]6Bi8I30 and [(CH3CH2)3S]AgBiI5 as scalable, cost-effective and highly stable alternatives to traditional semiconductor materials, offering great potential as X-ray detectors in medical and security applications.
KW - Mechanochemistry
KW - X-ray detectors
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630306
DO - https://doi.org/10.1002/adma.202418626
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-63030
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hendricks, A.
A1 - Phillips, T. K.
A1 - Engl, T.
A1 - Plarre, Rüdiger
A1 - Martinson, V. G.
T1 - The bacterial microbiome in spider beetles and deathwatch beetles
N2 - The beetle family Ptinidae contains a number of economically important pests, such as the cigarette beetle Lasioderma serricorne, the drugstore beetle Stegobium paniceum, and the diverse spider beetles. Many of these species are stored product pests, which target a diverse range of food sources, from dried tobacco to books made with organic materials. Despite the threat that the 2,200 species of Ptinidae beetles pose, fewer than 50 have been surveyed for microbial symbionts, and only a handful have been screened using contemporary genomic methods. In this study, we screen 116 individual specimens that cover most subfamilies of Ptinidae, with outgroup beetles from closely related families Dermestidae, Endecatomidae, and Bostrichidae. We used 16S ribosomal RNA gene amplicon data to characterize the bacterial microbiomes of these specimens. The majority of these species had never been screened for microbes. We found that, unlike in their sister family, Bostrichidae, that has two mutualistic bacteria seen in most species, there are no consistent bacterial members of ptinid microbiomes. For specimens which had Wolbachia infections, we did additional screening using multilocus sequence typing and showed that our populations have different strains of Wolbachia than noted in previous publications.
KW - Sodalis
KW - Ptinidae
KW - Anobiidae
KW - Bostrichidae
KW - Dermestidae
KW - Bostrichoidea
KW - Wolbachia
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-631564
DO - https://doi.org/10.1128/spectrum.01981-24
SN - 2165-0497
VL - 13
IS - 5
SP - 1
EP - 14
AN - OPUS4-63156
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Dural, Esra
A1 - Dey, R.
A1 - Ullrich, M. S.
A1 - Huth, Christian
A1 - Thomson, C.
A1 - Schartel, Bernhard
T1 - Together We Can: Synergistic Flame Retardancy by Melamine Polyphosphate and Phosphorylated Microalgae in Polylactide Biocomposites
N2 - A strategy for enhancing the sustainable flame retardancy of polylactide (PLA) composites by partially replacing melamine polyphosphate (MPP), a commercial flame retardant proposed for PLA, with wastewater polyphosphate-enriched microalgae (P-Algae) has been explored. The incorporation of P-Algae at a 1:1 ratio with MPP leads to a notable synergistic effect, surpassing the expected additive behavior of the individual components. Comprehensive characterization encompassing thermogravimetric analysis coupled with FTIR, pyrolysis combustion flow calorimeter (PCFC), cone calorimeter, oxygen index (LOI), UL-94 tests, and rheological measurements—demonstrates that the presence of this biomaterial can significantly enhance flame retardant performance. Replacing 50% of MPP with P-Algae in PLA resulted in a 17% reduction in peak heat release rate (pHRR) and maintained a V-0 rating in UL-94 testing. The use of P-Algae does not compromise the flame retardancy of PLA but rather contributes positively, offering a promising path toward more sustainable flame-retardant systems. By leveraging naturally derived biomass, this approach aligns with the growing demand for novel eco-friendly technologies in polymer engineering. Insights into an innovative renewable additive as a functional and effective component in flame-retardant biocomposites have been achieved.
KW - Flame retardancy
KW - Melamine polyphosphate
KW - Phosphorus- enriched microalgae
KW - Polylactide PLA
KW - Synergism
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640539
DO - https://doi.org/10.1002/pat.70350
SN - 1099-1581
SN - 1042-7147
VL - 36
IS - 9
SP - e70350
PB - John Wiley & Sons Ltd.
AN - OPUS4-64053
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Willms, Thomas
T1 - Beware the artifact: Generation of ellagic acid and related species during atmospheric solid analysis probe (ASAP) measurements of iron gall inks and tannins in the negative ionization mode
N2 - A detailed comparative analysis of the results of atmospheric solid analysis probe (ASAP) mass spectrometry of inks, tannins, and gallic acid (GA) in the negative ionization mode was performed. Results obtained for tannin by ASAP have been compared with those obtained with electrospray ionization (ESI). Apart from the GA ion, measurements frequently also yielded anions corresponding to association products and condensation products. At zero collision energy, pure GA gave a dimeric adduct (m/z 339); the formation of ions at m/z 303 and 304 was favored by increased temperatures and collision energies. In the case of inks, the subsequent dehydrogenation of such species to ellagic acid (EA) (m/z 301) was attributed to the oxidative effect of the iron III ion. On the basis of the results, a modification of the “standard ink protocol” has been suggested. Furthermore, several yet non‐described breakdown products and radical ion species of GA and EA ions were identified.
KW - Ink research
KW - ASAP
KW - Ellagic acid
KW - Gallic acid
KW - Metacyclophane
KW - Tannic acid
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659252
DO - https://doi.org/10.1002/jms.70045
SN - 1076-5174
VL - 61
IS - 4
SP - 1
EP - 20
PB - Wiley
CY - Chichester
AN - OPUS4-65925
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chan, Yin Yam
A1 - Schartel, Bernhard
T1 - It Takes Two to Tango: Synergistic Expandable Graphite–Phosphorus Flame Retardant Combinations in Polyurethane Foams
N2 - Due to the high flammability and smoke toxicity of polyurethane foams (PUFs) during burning, distinct efficient combinations of flame retardants are demanded to improve the fire safety of PUFs in practical applications. This feature article focuses on one of the most impressive halogen-free combinations in PUFs: expandable graphite (EG) and phosphorus-based flame retardants (P-FRs). The synergistic effect of EG and P-FRs mainly superimposes the two modes of action, charring and maintaining a thermally insulating residue morphology, to bring effective flame retardancy to PUFs. Specific interactions between EG and P-FRs, including the agglutination of the fire residue consisting of expanded-graphite worms, yields an outstanding synergistic effect, making this approach the latest champion to fulfill the demanding requirements for flame-retarded PUFs. Current and future topics such as the increasing use of renewable feedstock are also discussed in this article.
KW - Synergy
KW - Phosphorus-containing flame retardant
KW - Expandable graphite
KW - Polyurethane foams
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-551958
DO - https://doi.org/10.3390/polym14132562
SN - 2073-4360
VL - 14
IS - 13
SP - 2562
PB - MDPI
AN - OPUS4-55195
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frasca, Daniele
A1 - Schulze, Dietmar
A1 - Wachtendorf, Volker
A1 - Krafft, Bernd
A1 - Rybak, Thomas
A1 - Schartel, Bernhard
T1 - Multilayer Graphene/Carbon Black/Chlorine Isobutyl Isoprene Rubber Nanocomposites
N2 - High loadings of carbon black (CB) are usually used to achieve the properties demanded of rubber compounds. In recent years, distinct nanoparticles have been investigated to replace CB in whole or in part, in order to reduce the necessary filler content or to improve performance. Multilayer graphene (MLG) is a nanoparticle made of just 10 graphene sheets and has recently become commercially available for mass-product nanocomposites. Three phr (part for hundred rubbers) of MLG are added to chlorine isobutyl isoprene rubber (CIIR)/CB composites in order to replace part of the CB. The incorporation of just 3 phr MLG triples the Young’s modulus of CIIR; the same effect is obtained with 20 phr CB. The simultaneous presence of three MLG and CB also delivers remarkable properties, e.g. adding three MLG and 20 phr CB increased the hardness as much as adding 40 phr CB. A comprehensive study is presented, showing the influence on a variety of mechanical properties. The potential of the MLG/CB combination is illustrated to reduce the filler content or to boost performance, respectively. Apart from the remarkable mechanical properties, the CIIR/CB/MLG nanocomposites showed an increase in weathering resistance.
KW - nanocomposites
KW - rubber
KW - multilayer graphene
KW - carbon black
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-358569
DO - https://doi.org/10.3390/polym8030095
SN - 2073-4360
VL - 8
SP - 95
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-35856
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Narsabadi, Hossein
A1 - Vafaeenezhad, H.
A1 - Klotz, U.E.
A1 - Tiberto, D.
A1 - Hosseinabadi, F.
A1 - Mishurova, Tatiana
A1 - Bruno, Giovanni
A1 - Skrotzki, Birgit
T1 - XCT-assisted micromechanical modeling of the effect of pores on the plastic deformation and mechanical characteristics of PBF-LB/M-produced copper alloys
N2 - Due to the low absorption of fiber laser by copper particles, the laser-based powder bed fusion (PBF-LB/M) processing of copper components is accompanied by the development of different types of porosities within the printed samples. This research aims to assess the consequences of various process-induced pores on the me
chanical characteristics and deformation of PBF-LB/M-produced copper alloys. Several copper alloys were processed using metal-coated particles and varied laser intensities, yielding samples with different types and amounts of porosities. For instance, CuCrZr alloys processed at 325 J/mm³ and 257 J/mm³ had 0.009 % and 1.117 % porosities, dominated by keyhole and lack-of-fusion pores, respectively. Moreover, PBF-LB/M pro cessing of Cr- and Nb-coated CuNi3SiCr particles accompanied by the generation of 0.004 % and 1.861 % porosities within the samples, predominantly featuring metallurgical and oxidation pores, respectively.
Compression and nanoindentation tests revealed that the CuNi3SiCr alloy exhibited superior mechanical properties compared to the CuCrZr sample (nanoindentation hardness values 2.2 GPa and 1.4 GPa, respectively), while the presence of lack-of-fusion pores notably diminished their mechanical performance. X-ray computed tomography (XCT) reconstruction slices and scanning electron microscopy (SEM) images were then used for developing the representative volume elements (RVEs) based micromechanical models. The micromechanical
simulations established a structure-property correlation that can simulate the compressive deformation and mechanical characteristics of PBF-LB/M-produced copper alloys as a function of their incorporated pore characteristics. Due to the closure of the pores at the first stages of deformation, samples with minimal keyhole and metallurgical porosities exhibited homogeneous plastic deformation. On the other side, based on the JohnsonCook model, strain concentration and crack propagation around the lack-of-fusion pores lead to damage initi
ation in the printed samples at a strain level of 5 %
KW - X-ray Computed tomography
KW - Defects
KW - Copper alloys
KW - PBF-LB/M
KW - Micromechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624004
DO - https://doi.org/10.1016/j.msea.2025.147836
SN - 0921-5093
VL - 924
PB - Elsevier B.V.
AN - OPUS4-62400
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zerbst, Uwe
A1 - Madia, Mauro
A1 - Bruno, Giovanni
A1 - Hilgenberg, Kai
T1 - Towards a Methodology for Component Design of Metallic AM Parts Subjected to Cyclic Loading
N2 - The safe fatigue design of metallic components fabricated by additive manufacturing (AM) is still a largely unsolved problem. This is primarily due to (a) a significant inhomogeneity of the material properties across the component; (b) defects such as porosity and lack of fusion as well as pronounced surface roughness of the asuilt components; and (c) residual stresses, which are very often present in the as‐built parts and need to be removed by post‐fabrication treatments. Such morphological and microstructural features are very different than in conventionally manufactured parts and play a much bigger role in determining the fatigue life. The above problems require specific solutions with respect to the identification of the critical (failure) sites in AM fabricated components. Moreover, the generation of representative test specimens characterized by similar temperature cycles needs to be guaranteed if one wants to reproducibly identify the critical sites and establish fatigue assessment methods taking into account the effect of defects on crack initiation and early propagation. The latter requires fracture mechanics‐based approaches which, unlike common methodologies, cover the specific characteristics of so‐called short fatigue cracks. This paper provides a discussion of all these aspects with special focus on components manufactured by laser powder bed fusion (L‐PBF). It shows how to adapt existing solutions, identifies fields where there are still gaps, and discusses proposals for potential improvement of the damage tolerance design of L‐PBF components
KW - L‐PBF
KW - Fatigue
KW - Fracture
KW - Defects
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525822
DO - https://doi.org/10.3390/met11050709
VL - 11
IS - 5
SP - 709
PB - MDPI
CY - Basel
AN - OPUS4-52582
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ávila Calderón, Luis
A1 - Rehmer, Birgit
A1 - Schriever, Sina
A1 - Ulbricht, Alexander
A1 - Agudo Jácome, Leonardo
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
A1 - Evans, Alexander
T1 - Creep and creep damage behavior of stainless steel 316L manufactured by laser powder bed fusion
N2 - This study presents a thorough characterization of the creep properties of austenitic stainless steel 316L produced by laser powder bed fusion (LPBF 316L) contributing to the sparse available data to date. Experimental results (mechanical tests, microscopy, X-ray computed tomography) concerning the creep deformation and damage mechanisms are presented and discussed. The tested LPBF material exhibits a low defect population, which allows for the isolation and improved understanding of the effect of other typical aspects of an LPBF microstructure on the creep behavior. As a benchmark to assess the material properties of the LPBF 316L, a conventionally manufactured variant of 316L was also tested. To characterize the creep properties, hot tensile tests and constant force creep tests at 600 °C and 650 °C are performed. The creep stress exponents of the LPBF material are smaller than that of the conventional variant. The primary and secondary creep stages and the times to rupture of the LPBF material are shorter than the hot rolled 316L. Overall the creep damage is more extensive in the LPBF material. The creep damage of the LPBF material is overall mainly intergranular. It is presumably caused and accelerated by both the appearance of precipitates at the grain boundaries and the unfavorable orientation of the grain boundaries. Neither the melt pool boundaries nor entrapped gas pores show a significant influence on the creep damage mechanism.
KW - 316L
KW - Laser Powder Bed Fusion (LPBF)
KW - Creep behavior
KW - Additive Manufacturing
KW - AGIL
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-539373
DO - https://doi.org/10.1016/j.msea.2021.142223
SN - 0921-5093
VL - 830
SP - 142223
PB - Elsevier B.V.
AN - OPUS4-53937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Sanchez-Olivares, G.
A1 - Rockel, Daniel
A1 - Maldonado-Santoyo, M.
A1 - Schartel, Bernhard
T1 - Waste not, want not: The use of leather waste in flame retarded EVA
N2 - Leather is among the most ancient, widely used materials worldwide. Industrial-scale leather production produces large quantities of organic waste attained during shaving and buffing steps during processing. In this study, leather wastes (LW) are used as fillers in flame retarded polymer composites. LW is investigated as a multifunctional bio-filler that enhances the fire performance of flame retarded poly(ethylene–vinyl acetate) (EVA) containing phosphorus flame retardants (P-FRs) ammonium polyphosphate (APP) or a melamine-encapsulated APP (eAPP). Using LW from tanneries as adjuvants to enhance P-FRs in EVA reduces industrial wastes that otherwise require costly waste management solutions. Materials are characterized multi-methodically via mechanical tests, electron microscopy, rheology, thermogravimetric analysis, evolved gas analysis, and condensed phase FTIR, also reaction-to-small-flames and cone calorimeter tests. EVA containing 10 wt-% LW and 20 wt-% P-FRs achieve 20% reductions in fire loads versus EVA, and up to 10% reduction in effective heats of combustion versus EVA with equal (30 wt-%) P-FR loadings. Enhanced char stabilization of EVA composites with LW and P-FRs lowered peaks of heat release rates up to 53% compared to EVA, and up to 40% compared to equal P-FRs loadings. Synergisms between LW and P-FRs in EVA are quantified. A chemical decomposition mechanism is proposed.
KW - Leather waste
KW - Tannery industry
KW - EVA
KW - Fire protection
KW - Flame retardancy
KW - Charring
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532977
DO - https://doi.org/10.1016/j.matdes.2021.110100
SN - 0264-1275
VL - 210
SP - 1
EP - 16
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53297
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Abdou-Rahaman Fadul, Naïssa
A1 - Frasca, Daniele
A1 - Schulze, Dietmar
A1 - Schartel, Bernhard
T1 - Multifunctional graphene nanofiller in flame retarded polybutadiene/chloroprene/carbon black composites
N2 - To curtail flammability risks and improve material properties, flame retardants (FRs) and fillers are mixed into rubbers. High loadings of aluminum trihydroxide (ATH) and carbon black (CB) are the most used FRs and reinforcing additive, respectively, in rubbers. To reduce loading without losing mechanical properties, partial substitution of ATH as well as CB by low amounts of multilayer graphene (MLG) nanoparticles is investigated. The high aspect ratio MLG is made of ten graphene sheets. In polybutadiene/chloroprene (BR/CR) nanocomposites 3 phr MLG replaced 15 phr CB and/or 3 phr ATH. Material and mechanical properties as well as fire behavior of the nanocomposites are compared to BR/CR with 20 phr CB both with and without 50 phr ATH. MLG appears as a promising nanofiller to improve the functional properties: replacement of CB improved rheological, curing, and mechanical properties; substitution of ATH improved nanocomposite properties without affecting flame retardancy.
KW - Nanocomposites
KW - Rubber
KW - Multilayer graphene
KW - Carbon black
KW - Polybutadiene/chloroprene
KW - Graphene
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523468
DO - https://doi.org/10.1515/epoly-2021-0026
SN - 1618-7229
VL - 21
IS - 1
SP - 244
EP - 262
PB - De Gruyter
AN - OPUS4-52346
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tabaka, Weronika
A1 - Timme, Sebastian
A1 - Lauterbach, Tobias
A1 - Medina, L.
A1 - Berglund, L. A.
A1 - Carosio, F.
A1 - Duquesne, S.
A1 - Schartel, Bernhard
T1 - Bench-scale fire stability testing - Assessment of protective systems on carbon fibre reinforced polymer composites
N2 - Fire resistance testing of components made of carbon fibre reinforced polymers (CFRP) usually demands intermediate-scale or full-scale testing. A bench-scale test is presented as a practicable and efficient method to assess how different fire protective systems improve the structural integrity of CFRPs during fire. The direct flame of a fully developed fire was applied to one side of the CFRP specimen, which was simultaneously loaded with compressive force. Three different approaches (film, non-woven, and coatings) were applied: paper with a thickness in the range of μm consisting of cellulose nanofibre (CNF)/clay nanocomposite, nonwoven mats with thickness in the range of cm and intumescent coatings with a thickness in the range of mm. The uncoated specimen failed after just 17 s. Protection by these systems provides fire stability, as they multiply the time to failure by as much as up to 43 times. The reduced heating rates of the protected specimens demonstrate the reduced heat penetration, indicating the coatings’ excellent heat shielding properties. Bench-scale fire stability testing is shown to be suitable tool to identify, compare and assess different approaches to fire protection.
KW - Fire stability
KW - Bench-scale fire resistance
KW - Carbon fibre reinforced polymer
KW - Protective coatings
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-532401
DO - https://doi.org/10.1016/j.polymertesting.2021.107340
SN - 0142-9418
SN - 1873-2348
VL - 102
SP - 7340
PB - Elsevier
CY - Amsterdam
AN - OPUS4-53240
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Duarte, Larissa
A1 - Madia, Mauro
A1 - Zerbst, Uwe
T1 - The effect of the environmental conditions on the threshold against fatigue crack propagation
N2 - The threshold against fatigue crack propagation (ΔKth) is a crucial parameter for the damage tolerance assessment of engineering components subjected to cyclic loading and it is composed by two distinct components, one intrinsic, dependent on the elastic material properties and the lattice type, and one extrinsic, related to the occurrence of crack closure effects. An important issue is that several factors can influence ΔKth and, in general, the fatigue crack propagation behavior. In this work, the influence of the experimental procedure, air humidity, stress ratio and test frequency on da/dN-ΔK data has been investigated. Results are discussed with their potential causes and consequences on the calculations of the residual lifetime.
KW - Fatigue crack propagation threshold
KW - Crack closure effect
KW - Experimental procedure
KW - Environmental conditions
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544905
DO - https://doi.org/10.1016/j.prostr.2022.03.030
VL - 38
SP - 292
EP - 299
PB - Elsevier B.V.
AN - OPUS4-54490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinselman, Karen N.
A1 - Quine, Cullen M.
A1 - Hurst, Katie
A1 - Cho, Joy
A1 - Wenny, Malia B.
A1 - Mason, Jarad A.
A1 - Verma, Gaurav
A1 - Ma, Shengqian
A1 - Compton, Dalton
A1 - Stadie, Nicholas P.
A1 - Sengupta, Debabrata
A1 - Islamoglu, Timur
A1 - Farha, Omar K.
A1 - Zlotea, Claudia
A1 - Agafonov, Andrei
A1 - Asgari, Mehrdad
A1 - Al‐Shakhs, Ali
A1 - Lozano‐Castello, Dolores
A1 - Fairen‐Jimenez, David
A1 - Furukawa, Hiroyasu
A1 - Yabuuchi, Yuto
A1 - Broom, Darren P.
A1 - Benham, Michael J.
A1 - Villajos, José Antonio
A1 - Balderas‐Xicohténcatl, Rafael
A1 - Fackelmann, Isabella
A1 - Hirscher, Michael
A1 - Hoover, William J.
A1 - Morris, William
A1 - Wang, Timothy C.
A1 - Parilla, Philip A.
A1 - Gennett, Thomas
A1 - Shulda, Sarah
T1 - An international laboratory comparison study on approximating the enthalpy of adsorption via the Clausius‐Clapeyron approach
N2 - Materials‐based gas capture and storage is an increasingly important area of research. Robust and accurate determination of material properties is required for judicial selection of materials for specific applications and for engineering materials–based systems at scale. One key property is the strength of the adsorbate–adsorbent interaction often quantified via the isosteric enthalpy of adsorption. The heat of adsorption can be measured directly through calorimetry; however, a more widely used approach is to apply the Clausius‐Clapeyron (CC) equation to adsorption isotherms collected at different temperatures. While this approach appears to be straightforward, there exist multiple variants in the application of the methodologies employed. This raises the question on how these variations may or may not affect the determined results. Presented here is a discussion of the most common methodologies and a comparison of indirect determinations (via CC) of the isosteric enthalpy of adsorption by different laboratories on identical material. Included in that comparison are discussions on the measurement and analysis reproducibility. Importantly, details of the methodologies are shown to be critical when comparing enthalpies among laboratories, and different methodologies contribute to significant discrepancies and artifacts in the results. Recommendations are provided to promote robust determination and the reporting thereof.
KW - Adsorption enthalpy
KW - Enthalpy of adsorption
KW - Gas adsorption
KW - Isosteric heat
KW - Isotherm
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659306
DO - https://doi.org/10.1002/cphc.202500332
SN - 1439-4235
VL - 27
IS - 7
SP - 1
EP - 11
PB - Wiley
CY - Weinheim
AN - OPUS4-65930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Battig, Alexander
A1 - Müller, Patrick
A1 - Bertin, Annabelle
A1 - Schartel, Bernhard
T1 - Hyperbranched Rigid Aromatic Phosphorus-Containing Flame Retardants for Epoxy Resins
N2 - A rigid aromatic phosphorus-containing hyperbranched flame retardant structure is synthesized from 10-(2,5 dihydroxyphenyl)-10H-9-oxa-
10-phosphaphenanthrene-10-oxide (DOPO-HQ), tris(4-hydroxyphenyl)phosphine oxide (THPPO), and 1,4-terephthaloyl chloride (TPC). The resulting poly-(DOPO-HQ/THPPO-terephthalate) (PDTT) is implemented as a flame retardant into an epoxy resin (EP) at a 10 wt% loading. The effects on EP are compared with those of the monomer DOPO-HQ and triphenylphosphine oxide (OPPh3) as low molar mass flame retardants. The glass transition temperature, thermal decomposition, flammability (reaction to small flame), and burning behavior of the thermosets are investigated using differential scanning calorimetry, thermogravimetric analysis, pyrolysis combustion flow calorimetry, UL 94-burning chamber testing, and cone calorimeter measurements.
Although P-contents are low at only 0.6 wt%, the study aims not at attaining V-0, but at presenting a proof of principle: Epoxy resinswith PDTT show promising fire performance, exhibiting a 25% reduction in total heat evolved (THE), a 30% reduction in peak heat release rate (PHRR) due to flame inhibition (21% reduction in effective heat of combustion (EHC)), and an increase in Tg at the same time. This study indicates that rigid aromatic hyperbranched polymeric structures offer a promising route toward multifunctional flame retardancy.
KW - Hyperbranched
KW - Aromatic
KW - Phosphorus
KW - Phosphine oxide
KW - DOPO
KW - Flame retardant
KW - Xpoxy resin
KW - Rigid
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525910
DO - https://doi.org/10.1002/mame.202000731
SN - 1439-2054
VL - 306
IS - 4
SP - 731
PB - Wiley
AN - OPUS4-52591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zhu, Jiangchao
A1 - Madia, Mauro
A1 - Schurig, Michael
A1 - Kruse, Julius
A1 - Conrad, Fabian
A1 - Schlums, Hartmut
A1 - Kontermann, Christian
A1 - Zerbst, Uwe
T1 - On the use of representative specimens for the structural integrity assessment of safety-relevant rotating components
N2 - Safety-relevant components, for which a failure in service could have catastrophic consequences, are usually designed for extremely low probability of failure and they are subjected to stringent part qualification procedures according to guidelines set by regulatory agencies. Manufacturers are often forced to perform tests on full scale or scaled components to ensure the structural integrity under defined loading conditions, which usually implies a huge experimental and financial effort. Therefore, companies try to develop new strategies such as digital twins, which allow to massively reduce costs, without compromising safety. This work presents a new quasi-static testing and assessment concept, the main idea of which is to replace, or at least reduce, the experimental testing on components by testing specimens representative of the component.
Fracture mechanics specimens have been designed iteratively by numerical simulations to match the stress state at the crack-tip of the maximum permissible defect defined by regulatory agencies for the component. Potentially, the major benefit of the proposed approach is that the tests can be performed on conventional laboratory testing machines. The effectiveness of the methodology is demonstrated in case of the structural integrity assessment of a Ni-base superalloy aero-engine turbine disk at overspeed conditions.
KW - Structural integrity
KW - Turbine disk
KW - Burst
KW - Fracture mechanics
KW - Representative specimens
KW - Quasi-static testing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624208
DO - https://doi.org/10.1016/j.engfracmech.2024.110710
SN - 0013-7944
VL - 314
SP - 1
EP - 23
PB - Elsevier Ltd.
AN - OPUS4-62420
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strauß, Lea
A1 - Duarte, Larissa
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Löwisch, Günther
T1 - An equivalent stress approach for predicting fatigue behavior of additively manufactured AlSi10Mg
N2 - Laser-based powder bed fusion (PBF-LB) is an advanced additive manufacturing technique renowned for its precision and capability to fabricate complex metal components. However, the high thermal gradients and rapid cooling rates intrinsic to this process introduce significant process-induced effects, such as inhomogeneities, surface roughness, anisotropy, and residual stress, all of which critically influence the fatigue behavior of the produced parts. This study investigates the fatigue performance of AlSi10Mg samples produced by PBF-LB, examining the impact of varying surface conditions, geometries, and residual stress levels. Fatigue-life prediction models are formulated based on nominal stress amplitude, residual stress, form factor, crack-initiating inhomogeneity, and surface roughness, with smooth samples serving as a baseline reference. The study presents two empirical models for predicting fatigue life and fatigue strength using S–N curves and the Kitagawa–Takahashi diagram with the El Haddad approach, derived from comprehensive experimental data, including finite element modeling, fatigue-life measurements, surface roughness evaluations, and residual stress analysis.
KW - AlSi10Mg
KW - Kitagawa–Takahashi diagram
KW - El Haddad
KW - Equivalent stress
KW - Fatigue-life prediction
KW - PBF-LB/M
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-625176
DO - https://doi.org/10.1007/s40964-025-00974-0
SP - 1
EP - 16
PB - Springer Science and Business Media LLC
AN - OPUS4-62517
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Norouzi, Ebrahim
A1 - Sack, Harald
A1 - Skrotzki, Birgit
T1 - Performance Evaluation of Upper‐Level Ontologies in Developing Materials Science Ontologies and Knowledge Graphs
N2 - This study tackles a significant challenge in ontology development for materials science: selecting the most appropriate upper‐level ontologies for creating application‐level ontologies and knowledge graphs. Focusing on the use case of Brinell hardness testing, the research assesses the performance of various top‐level ontologies (TLOs)—basic formal ontology (BFO), elementary multiperspective material ontology (EMMO), and provenance ontology (PROVO)—in developing Brinell testing ontologies (BTOs). Consequently, three versions of BTOs are created using combinations of these TLOs along with their integrated mid‐ and domain‐level ontologies. The performance of these ontologies is evaluated based on ten parameters: semantic richness, domain coverage, extensibility, complexity, mapping efficiency, query efficiency, integration with other ontologies, adaptability to different data contexts, community acceptance, and documentation and maintainability. The results show that all candidate TLOs can effectively develop BTOs, each with its distinct advantages. BFO provides a well‐structured, understandable hierarchy, and excellent query efficiency, making it suitable for integration across various ontologies and applications. PROVO demonstrates balanced performance with strong integration capabilities. Meanwhile, EMMO offers high semantic richness and domain coverage, though its complex structure impacts query efficiency and integration with other ontologies.
KW - Materials Science
KW - Ontology
KW - Knowledge Graph
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612227
DO - https://doi.org/10.1002/adem.202401534
SN - 1527-2648
SP - 1
EP - 18
PB - Wiley
AN - OPUS4-61222
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Yusenko, Kirill
A1 - King, Andrew
A1 - Meyer, Klas
A1 - Al-Sabbagh, Dominik
A1 - Villajos, José Antonio
A1 - Emmerling, Franziska
T1 - Lighting up industrial mechanochemistry: Real-time in situ monitoring of reactive extrusion using energy-dispersive X-ray diffraction
N2 - Mechanochemistry is an environmentally friendly synthetic approach that enables the sustainable production of a wide range of chemicals while reducing or eliminating the need for solvents. Reactive extrusion aims to move mechanochemistry from its conventional gram-scale batch reactions, typically performed in laboratory ball mills, to a continuous, large-scale process. Meeting this challenge requires in situ monitoring techniques to gain insights into reactive extrusion and its underlying processes. While the effectiveness of in situ Raman spectroscopy in providing molecular-level information has been demonstrated, our study uses energy-dispersive X-ray diffraction to monitor reactive extrusion in real time at the crystalline level. Our results provide previously unavailable control over the reactive extrusion process, promoting its perception as an industrially feasible green alternative to traditional solvent-based syntheses.
KW - Mechanochemistry
KW - Reactive extrusion
KW - Green chemistry
KW - In situ studies
KW - Time-resolved in situ
KW - TRIS
KW - Synchrotron radiation
KW - Scalable synthesis
KW - Solid-state reactions
KW - Reaction mechanisms
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-613969
DO - https://doi.org/10.1016/j.chempr.2024.07.033
VL - 10
IS - 11
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-61396
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Fedelich, Bernard
A1 - Jokisch, T.
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Fatigue crack growth behavior of Alloy 247DS brazed joints at high temperatures
N2 - Gas turbine components made of nickel-based alloys can be repaired through diffusion brazing. However, process-induced imperfections, defects within the brazing zone, and material property mismatches between the braze alloy and base material may facilitate crack initiation and propagation, ultimately leading to early component failure. To gain insight into the crack growth mechanism and quantitatively characterize fatigue crack growth behavior within brazing zones, fatigue crack growth (FCG) experiments were conducted on brazed joint specimens of nickel-based alloy Alloy 247DS at a temperature of 950 ◦C and a stress ratio R = 0.1. The FCG tests were complemented by fractographic and microstructural analyses, to elucidate the relationship between crack growth mechanisms and the microstructure of the brazed joint. The results demonstrate stable crack propagation within the brazing zone and the nickel-based braze alloy. The latter contains brittle eutectic boride phases and intermetallic phases that reduce the resistance to crack propagation compared to the parent material. This study demonstrates the applicability of standard FCG experimental procedures to fusion zones, thereby enabling a preliminary understanding of crack growth behavior in brazing zones.
KW - Diffusion brazing
KW - High-temperature fatigue crack growth
KW - Nickel-based alloys
KW - Alloy 247DS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615250
DO - https://doi.org/10.1016/j.msea.2024.147488
SN - 0921-5093
VL - 918
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-61525
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jauregui Rozo, Maria
A1 - Sunder, S:
A1 - Ruckdäschel, H.
A1 - Schartel, Bernhard
T1 - Char, gas, and action: Transfer of the flame-retardant modes of action in epoxy resins and their fiber-reinforced composites
N2 - Flame retardants are often developed for epoxy resins and then transferred into their fiber-reinforced composites with uncertain results. Understanding this transfer in detail represents a critical scientific challenge. This study systematically compares epoxy resins with their glass-fiber reinforced composites, focusing on bisphenol A diglycidyl ether with the hardener dicyandiamide, the flame retardants melamine polyphosphate, ammonium polyphosphate, and silane ammonium polyphosphate, along with inorganic silicate. The research investigates changes in pyrolysis (thermogravimetry), flammability (UL 94, limiting oxygen index), and fire behavior (cone calorimeter) while also examining the flame-retardant modes of action and overall fire performance. The findings reveal that alterations in the amount of fuel, thermal properties, melt flow, and protective layer significantly impact ignition, flammability, and fire load, with a critical reduction in carbonaceous char within the composites preventing intumescence. This study quantifies the effects and provides a fundamental scientific understanding of the complex transfer process of flame retardants from resins to composites, offering essential insights that are of major importance for developing more effective flame-retardant materials.
KW - Glas fibers
KW - Epoxy resins
KW - Fire behavior
KW - Flammability
KW - Composites
KW - Flame retardants
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615371
DO - https://doi.org/10.1016/j.polymertesting.2024.108610
SN - 0142-9418
SN - 1873-2348
VL - 140
PB - Elsevier Ltd.
AN - OPUS4-61537
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hupp, Vitus
A1 - Schartel, Bernhard
A1 - Flothmeier, K.
A1 - Hartwig, A.
T1 - Flame Retarded Adhesive Tapes and Their Influence on the Fire Behavior of Bonded Parts
N2 - Pressure-sensitive adhesive tapes are used in automotives, railway vehicles
and construction, where flame retardancy is of major importance. This is why industrial applicants often buy, and industrial tape manufacturers often produce, flame-retardant adhesive tapes, advertised for their good flammability characteristics. Yet, how flame-retardant tapes influence the fire behavior of bonded materials is a rather open question. To investigate this issue, three different substrates were bonded, using eight double-sided adhesive tapes containing two different carriers and two different flame retardants. The bonded substrates were compared to their monolithic counterparts in terms of flammability, fire behavior and fire stability. The fire behavior of adhesive tape bonded materials differed significantly from the monolithic substrates. The usage of different adhesive tapes let to different burning behavior of the bonded materials mainly due to different carrier systems. In contrast, the implementation of flame retardant into the adhesive had rather minor or no effect on the burning behavior of the bonded substrates despite their positive effect on the flammability of the free-standing tape. The carrier changed the HRR curve in the cone calorimeter and was able to both, reduce and increase fire hazards. Using the carrier with the better fire performance can lower the fire growth rate by 20%, the peak of heat release rate by 27%, and the maximum average rate of heat emission by 30% in cone calorimeter tests. Overall, the fire behavior of bonded materials is a complex interaction between substrate, adhesive, and carrier, and depends on the fire scenario the materials are exposed to.
KW - Pressure-sensitive adhesive tapes
KW - Bonded materials
KW - Fire behaviour
KW - Fire resistance
KW - Flame retardant
KW - Cone calorimeter
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626006
DO - https://doi.org/10.1007/s10694-024-01637-2
SN - 1572-8099
SN - 0015-2684
VL - 61
IS - 2
SP - 729
EP - 749
PB - Springer Nature
AN - OPUS4-62600
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scacco, F.
A1 - Zerbst, Uwe
A1 - Meneghetti, G.
A1 - Madia, Mauro
T1 - Comparison between PSM and IBESS approaches for the fatigue life estimation of weldments
N2 - In the framework of the fatigue assessment of welded components, several methods are available in design standards such as the nominal stress, hot-spot stress, notch stress and linear elastic fracture mechanics approaches. The present paper aims at comparing two advanced local approaches for the fatigue strength assessment of different welded joints made of steel. The first one is IBESS which is based on short crack fracture mechanics. The second one is the PSM which instead involves the strain energy density approach. Both methods will be briefly presented, and the fatigue life prediction results discussed. The results obtained for the joint geometries considered in this work show advantages and drawbacks of the approaches, which are thoroughly analysed as well.
KW - Fatigue
KW - Welded joints
KW - FAT class
KW - IBESS
KW - Peak stress method (PSM)
KW - Finite element (FE)
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545139
DO - https://doi.org/10.1007/s40194-022-01284-7
SP - 1
EP - 23
PB - Springer
AN - OPUS4-54513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Mishurova, Tatiana
A1 - Madia, Mauro
A1 - Pirling, T.
A1 - Evans, Alexander
A1 - Klaus, M.
A1 - Haubrich, J.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Influence of a 265 °C heat treatment on the residual stress state of a PBF-LB/M AlSi10Mg alloy
N2 - Laser Powder Bed Fusion (PBF-LB/M) additive manufacturing (AM) induces
high magnitude residual stress (RS) in structures due to the extremely heterogeneous cooling and heating rates. As the RS can be deleterious to the fatigue resistance of engineering components, great efforts are focused on understanding their generation and evolution after post-process heat treatments. In this study, one of the few of its kind, the RS relaxation induced in an as-built PBF-LB/M AlSi10Mg material by a low-temperature heat treatment (265 °C for 1 h) is studied by means of X-ray and neutron diffraction. Since the specimens are manufactured using a baseplate heated up to 200 °C, low RS are found in the as-built condition. After heat treatment a redistribution of the RS is observed, while their magnitude remains constant. It is proposed that the redistribution is induced by a repartition of stresses between the a-aluminium matrix and the silicon phase, as the morphology of the silicon phase is affected by the heat treatment. A considerable scatter is observed in the neutron diffraction RS profiles, which is principally correlated to the presence (or absence) of pockets of porosity developed at the borders of the chessboard pattern.
KW - Neutron diffraction
KW - Additive manufacturing
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-565115
DO - https://doi.org/10.1007/s10853-022-07997-w
SN - 1573-4803
VL - 57
SP - 22082
EP - 22098
PB - Springer Science + Business Media
CY - Dordrecht
AN - OPUS4-56511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sänger, Johanna Christiane
A1 - Pauw, Brian Richard
A1 - Riechers, Birte
A1 - Zocca, Andrea
A1 - Rosalie, Julian
A1 - Maaß, Robert
A1 - Sturm, Heinz
A1 - Günster, Jens
T1 - Entering a new dimension in powder processing for advanced ceramics shaping
N2 - Filigree structures can be manufactured via two-photon-polymerization (2PP) operating in the regime of non-linear light absorption. For the first time it is possible to apply this technique to the powder processing of ceramic structures with a feature size in the range of the critical defect size responsible for brittle fracture and, thus, affecting fracture toughness of high-performance ceramics. In this way, tailoring of advanced properties can be achieved already in the shaping process. Traditionally, 2PP relies on transparent polymerizable resins, which is diametrically opposed to the usually completely opaque ceramic resins and slurries. Here we present a transparent and photocurable suspension of nanoparticles (resin) with very high mass fractions of yttria-stabilized zirconia particles (YSZ). Due to the extremely well dispersed nanoparticles, scattering of light can be effectively suppressed at the process-relevant wavelength of 800 nm. Sintered ceramic structures with a resolution of down to 500 nm were obtained. Even at reduced densities of 1 to 4 g/cm³, the resulting compressive strength with 4,5 GPa is equivalent or even exceeding bulk monolithic yttria stabilized zirconia. A ceramic metamaterial is born, where the mechanical properties of yttria stabilized zirconia are altered by changing geometrical parameters and gives access to a new class of ceramic materials.
KW - Two-photon-polymerization
KW - Ceramics
KW - Powder processing
KW - Transparency
KW - Meta material
KW - Yttria stabilized zirconia
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-564598
DO - https://doi.org/10.1002/adma.202208653
SN - 1521-4095
SP - 1
EP - 8
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-56459
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Werner, Tiago
A1 - Madia, Mauro
A1 - Zerbst, Uwe
T1 - Comparison of the fatigue behavior of wrought and additively manufactured AISI 316L
N2 - Additive manufacturing (AM) is becoming increasingly important in engineering applications due to the possibility of producing components with a high geometrical complexity allowing for optimized forms with respect to the in-service functionality. Despite the promising potential, AM components are still far from being used in safety-relevant applications, mainly due to a lack of understanding of the feedstock-process-properties-performance relationship. This work aims at providing a full characterization of the fatigue behavior of the additively manufactured AISI 316L austenitic stainless steel and a direct comparison with the fatigue performance of the wrought steel. To this purpose, a set of specimens has been produced by laser powder bed fusion (L-PBF) and subsequently heat treated at 900 °C for 1 hour for complete stress relief, whereas a second set of specimens has been machined out of hot-rolled plates. Low cycle fatigue (LCF) and high cycle fatigue (HCF) tests have been conducted for characterizing the fatigue behavior. The L-PBF material had a higher fatigue limit and better finite life performance compared to wrought material. Both, LCF and HCF-testing revealed an extensive cyclic softening.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Additive manufacturing
KW - L-PBF
KW - 316L
KW - Fatigue
KW - LCF
KW - HCF
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544952
DO - https://doi.org/10.1016/j.prostr.2022.03.056
SN - 2452-3216
VL - 38
SP - 554
EP - 563
PB - Elsevier B.V.
AN - OPUS4-54495
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chen, Yue
A1 - Schilling, Markus
A1 - von Hartrott, P.
A1 - Beygi Nasrabadi, Hossein
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Ontopanel: A Tool for Domain Experts Facilitating Visual Ontology Development and Mapping for FAIR Data Sharing in Materials Testing
N2 - In recent years, the design and development of materials are strongly interconnected with the development of digital technologies. In this respect, efficient data management is the building block of material digitization and, in the field of materials science and engineering (MSE), effective solutions for data standardization and sharing of different digital resources are needed. Therefore, ontologies are applied that represent a map of MSE concepts and relationships between them. Among different ontology development approaches, graphical editing based on standard conceptual modeling languages is increasingly used due to its intuitiveness and simplicity. This approach is also adopted by the Materials-open-Laboratory project (Mat-o-Lab), which aims to develop domain ontologies and method graphs in accordance with testing standards in the field of MSE. To suit the actual demands of domain experts in the project, Ontopanel was created as a plugin for the popular open-source graphical editor diagrams.net to enable graphical ontology editing. It includes a set of pipeline tools to foster ontology development in diagrams.net, comprising imports and reusage of ontologies, converting diagrams to Web Ontology Language (OWL), verifying diagrams using OWL rules, and mapping data. It reduces learning costs by eliminating the need for domain experts to switch between various tools. Brinell hardness testing is chosen in this study as a use case to demonstrate the utilization of Ontopanel.
KW - Materials Testing
KW - Ontology
KW - Visual ontology development
KW - Data mapping
KW - FAIR
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-560339
DO - https://doi.org/10.1007/s40192-022-00279-y
SP - 1
EP - 12
PB - Springer
AN - OPUS4-56033
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Werner, Tiago
A1 - Blasón Gonzalez, Sergio
A1 - Madia, Mauro
A1 - Kruse, Julius
A1 - Benedetti, Matteo
T1 - Determination of fatigue crack propagation thresholds using small-scale specimens
N2 - The damage tolerance approach is widely used in the design and estimation of inspection intervals of safety-relevant metallic components subject to fatigue loading. The approach relies on the knowledge of the fatigue crack propagation characteristics, wherein a relevant role is played by the fatigue crack propagation threshold. Nevertheless, the use of material data determined by testing on conventional specimens is not straightforward in the case of thin-walled components such as turbine blades or additively manufactured parts, in which the local variation of material properties in highly stressed regions must be considered. In these cases, the possibility of investigating the fatigue crack propagation properties on a limited portion of material is crucial. For this purpose, a new test procedure has been developed for small-scale specimens which allows the determination of the intrinsic fatigue crack propagation threshold and the near-threshold regime. The validity and limitations of the method are demonstrated on the high strength steel S960QL, along with a comparison with data determined by testing on conventional geometries.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue crack propagation threshold
KW - Small-scale specimens
KW - High strength steel
KW - Crack-tip constraint
KW - Damage tolerance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544967
DO - https://doi.org/10.1016/j.prostr.2022.03.031
SN - 2452-3216
VL - 38
SP - 300
EP - 308
PB - Elsevier B.V.
AN - OPUS4-54496
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Kromm, Arne
A1 - Madia, Mauro
T1 - Investigation of residual stresses and microstructure effects on the fatigue behaviour of a L-PBF AlSi10Mg alloy
N2 - Al-Si alloys produced by Laser Powder Bed Fusion (L-PBF) techniques allow the fabrication of lightweight free-shape components that find space in aerospace, automotive, biomedical and military applications. Due to the high cooling rates occurring during the building process, L-PBF AlSi10Mg alloys exhibit an ultra-fine microstructure that leads to superior mechanical properties in the as-built condition compared to conventional cast Al-Si materials. Nevertheless, L-PBF processing induces high thermal gradients, leading to deleterious residual stress levels that must be considered to avoid part distortion and unpredicted failures. In order to relax detrimental residual stress and to increase the ductility, post-processing stress relief treatments are generally performed. In as-built condition the hypoeutectic AlSi10Mg microstructure consist of fine α-Al cells containing uniformly dispersed silicon nanoparticles, which are, in addition, surrounded by a eutectic Si network. Above 260°C the silicon interconnectivity starts to breakdown into spheroidized particles and to coarsen. At the same time, the heating residual stresses are relieved.
The objective of the contribution is to investigate, under different heat treatment conditions, the evolution of microstructure and residual stresses in view of optimizing the fatigue performance of the alloy. To this purpose various heat treatments in a range of temperatures between 265°C and 300°C for a duration between 15 minutes and 2 hours are performed. The microstructure modifications are analysed using a scanning electron microscope and the residual stress state is measured by laboratory X-ray diffraction.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - AlSi10Mg alloy
KW - Additive manufacturing
KW - L-PBF
KW - Residual stress
KW - Heat treatment
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544942
DO - https://doi.org/10.1016/j.prostr.2022.03.057
SN - 2452-3216
VL - 38
SP - 564
EP - 571
PB - Elsevier B.V.
AN - OPUS4-54494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gugin, Nikita
A1 - Villajos, José Antonio
A1 - Feldmann, Ines
A1 - Emmerling, Franziska
T1 - Mix and wait – a relaxed way for synthesizing ZIF-8
N2 - Herein we report the synthesis of a zeolitic imidazolate framework (ZIF-8) by an easy “mix and wait” procedure. In a closed vial, without any interference, the mixture of 2-methylimidazole and basic zinc carbonate assembles into the crystalline product with approx. 90% conversion after 70 h. The reaction exhibits sigmoidal kinetics due to the self-generated water which accelerates the reaction.
KW - In-situ analysis
KW - Mechanochemistry
KW - MOF
KW - Synthesis
KW - ZIF-8
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546841
DO - https://doi.org/10.1039/D2RA00740A
VL - 12
SP - 8940
EP - 8944
PB - Royal Society of Chemistry
AN - OPUS4-54684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Werner, Tiago
T1 - Estimation of the Kitagawa-Takahashi diagram by cyclic R curve analysis
N2 - The Kitagawa-Takahashi (KT) diagram is a proven concept for describing the fatigue limit in presence of a defect or crack. It can be determined empirically with great experimental effort. It can also be estimated by means of the El Haddad relationship if the endurance limit and the long fatigue crack propagation threshold are available in reasonable accuracy. A third option is the determination using the cyclic R-curve, which describes the dependency of the fatigue crack propagation threshold on the crack growth at the short crack propagation stage. This can be experimentally determined using a closure-free initial pre-crack. It can then be applied to the determination of crack arrest for a given applied load and a given defect or crack size. Compared to the other two methods mentioned above, this option has considerable advantages: It can be applied to any component and any stress ratio. It allows the treatment of multiple cracks and provides estimations of the S-N curve in the finite life regime as well as at the endurance limit. Compared to the empirical determination of the KT diagram, the experimental effort is significantly lower and compared to the El Haddad approach it avoids problems such as the use of non-conservative long fatigue crack propagation thresholds (when the conventional load reduction method is applied to materials prone to corrosion) and the mathematical predetermination of the curve shape. The work introduces the method and provides a critical discussion as well as quantitative comparison between the different methods.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue life
KW - Endurance limit
KW - Kitagawa-Takahashi diagram
KW - Cyclic R-curve
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544931
DO - https://doi.org/10.1016/j.prostr.2022.03.032
SN - 2452-3216
VL - 38
SP - 309
EP - 316
PB - Elsevier B.V.
AN - OPUS4-54493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kempf, Andreas
A1 - Kruse, Julius
A1 - Madia, Mauro
A1 - Hilgenberg, Kai
T1 - Correlation between quasistatic und fatigue properties of additively manufactured AlSi10Mg using Laser Powder Bed Fusion
N2 - In order to find a resource efficient approach for the fatigue lifetime prediction of laser powder bed fusion (L-PBF) processed AlSi10Mg material, results of tensile and fatigue tests were compared. The specimens were manufactured with three different L-PBF machines and studied in different heat treatment conditions (as-built, annealed, T6 heat treated). The investigations showed that the high attainable tensile strength properties after the manufacturing process are not beneficial in the high cycle fatigue (HCF) regime. In contrast, the applied heat treatments, which lead typically to a decrease of ultimate tensile strength, improved dramatically the fatigue behavior. Additionally, a clear correlation between the elongation at fracture and HCF resistance has been found for individual heat treatment conditions. This empiric relationship provides an estimation of the fatigue resistance in the presence of material defects and can be implemented in part and process approvals.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Additive Manufacturing
KW - Laser powder bed fusion
KW - AlSi10Mg
KW - Tensile properties
KW - Fatigue properties
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544921
DO - https://doi.org/10.1016/j.prostr.2022.03.009
SN - 2452-3216
VL - 38
SP - 77
EP - 83
PB - Elsevier B.V.
AN - OPUS4-54492
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bhadeliya, Ashok
A1 - Rehmer, Birgit
A1 - Fedelich, Bernard
A1 - Jokisch, T.
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Fatigue and fracture in dual-material specimens of nickel-based alloys fabricated by hybrid additive manufacturing
N2 - The integration of additive manufacturing with traditional processes, termed hybrid additive manufacturing, has expanded its application domain, particularly in the repair of gas turbine blade tips. However, process-related defects in additively manufactured materials, interface formation, and material property mismatches in dual-material structures can significantly impact the fatigue performance of components. This investigation examines the low cycle fatigue and fatigue crack growth behaviors in dual-material specimens of nickel-based alloys, specifically the additively manufactured STAL15 and the cast alloy 247DS, at elevated temperatures. Low cycle fatigue experiments were conducted at temperatures of 950 °C and 1000 °C under a range of strain levels (0.3%–0.8%) and fatigue crack growth tests were conducted at 950 °C with stress ratios of 0.1 and −1. Fractographic and microscopic analyses were performed to comprehend fatigue crack initiation and crack growth mechanisms in the dual-material structure. The results consistently indicated crack initiation and fatigue fracture in the additively manufactured STAL15 material. Notably, fatigue crack growth retardation was observed near the interface when the crack extended from the additively manufactured STAL15 material to the perpendicularly positioned interface. This study highlights the importance of considering yield strength mismatch, as well as the potential effects of residual stresses and grain structure differences, in the interpretation of fatigue crack growth behavior at the interface.
KW - Hybrid additive manufacturing
KW - Dual-material nickel-based alloys
KW - High-temperature fatigue crack growth
KW - Low cycle fatigue
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-609340
DO - https://doi.org/10.1016/j.jmrt.2024.08.211
SN - 2238-7854
VL - 32
SP - 3737
EP - 3749
PB - Elsevier B.V.
AN - OPUS4-60934
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rockel, Daniel
A1 - Sanchez Olivares, G.
A1 - Schartel, Bernhard
T1 - Improving the Flame Retardancy of Aluminium Trihydroxide in Thermoplastic Starch Biocomposites Using Waste Fibers and Silicon-Based Synergists
N2 - The synergistic behavior of different silicon compounds is investigated in flame retardant biocomposites with aluminum trihydroxide (ATH) as the main flame retardant. The paper shows a new approach towards sustainable biocomposites through the implementation of thermoplastic starch (TPS), leather fibers from industrial waste streams, and non-hazardous flame retardants and synergists. In these multicomponent systems, the different components address different modes of action in the fire scenario. When ATH is partially substituted by glass frits or layered silicates, fire performance is enhanced without changing the total amount of filler in the polymer. In a biocomposite with 25 phr of fiber and 90 phr of ATH, substituting 5 phr of ATH for layered silicates increased the LOI from 31.5 vol % to 34.8 vol %, decreased the peak of heat release by 20%, and increased the UL 94 rating from V-1 to V-0.
KW - Biocomposites
KW - Sustainability
KW - Waste streams
KW - Flame retardancy
KW - Synergism
KW - Modes of action
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605711
DO - https://doi.org/10.1021/acssusresmgt.4c00053
SN - 2837-1445
VL - 1
IS - 6
SP - 1131
EP - 1145
PB - ACS
AN - OPUS4-60571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dudziak, Mateusz
A1 - Bhatia, Riya
A1 - Dey, R.
A1 - Falkenhagen, Jana
A1 - Ullrich, M. S.
A1 - Thomsen, C.
A1 - Schartel, Bernhard
T1 - Wastewater phosphorus enriched algae as a sustainable flame retardant in polylactide
N2 - Revolutionizing our polymer industry for adaption to a sustainable carbon circular economy has become one of today’s most demanding challenges. Exploiting renewable resources to replace fossil-fuel—based plastics with biopolymers such as poly(lactic acid) (PLA) is inevitable while using waste streams as a raw material resource at least is promising. When it comes to using PLA as technical polymer, its high flammability must be addressed by flame retardants compatible with the thermoplastic processing of PLA and its compostability. This study proposes microalgae enriched with phosphorus from wastewater (P-Algae) as an elegant way towards a kind of sustainable organophosphorus flame retardant. The concept is demonstrated by investigating the processing, pyrolysis, flammability, and fire behavior of PLA/P-Algae, while varying the P-Algae content and comparing P-Algae with four alternative bio-fillers (phosphorylated lignin, biochar, thermally treated sewage sludge, and metal phytate) with different P-contents as meaningful benchmarks.
KW - PLA
KW - Flame Retardancy
KW - Phosphorylated Algae
KW - Wastewater flame retardants
KW - Zink phytate
KW - Phosphorylated lignin
KW - Thermally treated sludge
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-604150
DO - https://doi.org/10.1016/j.polymdegradstab.2024.110885
SN - 1873-2321
SN - 0141-3910
VL - 227
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-60415
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rashidi, Reza
A1 - Riechers, Birte
A1 - Rosalie, Julian
A1 - Maaß, Robert
T1 - Annealing-dependent elastic microstructure in a Zr-based metallic glass
N2 - In this letter, we demonstrate the robust presence of an elastic microstructure in a Zr-based metallic glass (MG) with a characteristic length-scale of the order of 100 nm. This length scale increases systematically towards the MG surface in differently sized casts, whereas thermal relaxation homogenizes both the internal length-scale gradient and the magnitude of the elastic fluctuations. Strongest changes during relaxation arise in the stiffest parts of the elastic microstructure. These findings indicate that the elastic microstructure emerges due to cooling constraints and may therefore be a microstructural manifestation of the internal residual stresses that arise during MG-solidification.
KW - Metallic glass
KW - Heterogeneity
KW - Elastic microstructure
KW - Nanoindentation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610962
DO - https://doi.org/10.1016/j.scriptamat.2024.116380
VL - 255
SP - 1
EP - 5
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-61096
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sunder, S.
A1 - Jauregui Rozo, Maria
A1 - Inasu, S.
A1 - Schartel, Bernhard
A1 - Ruckdäschel, H.
T1 - A systematic investigation of the transfer of polyphosphate/inorganic silicate flame retardants from epoxy resins to layered glass fiber-reinforced composites and their post-furnace flexural properties
N2 - The systematic transfer of solvent-free, additive flame retardant (FR) formulations from epoxy resins to glass fiber-reinforced epoxy composites (GFRECs) through prepregs is difficult. Additionally, obtaining data on their post-fire mechanics is often challenging. Utilizing melamine polyphosphate (MPP), ammonium polyphosphate (APP), and silane-coated ammonium polyphosphate (SiAPP) FRs with low-melting inorganic silicates (InSi) in an 8:2 proportion and 10% loading by weight in a diglycidyl ether of bisphenol A (DGEBA) resin, a systematic investigation of the processing properties, room-temperature mechanics, and temperature-based mechanics of the systems was performed. The resin was cured with a dicyandiamide hardener (DICY) and a urone accelerator. The results revealed no substantial impact of these FRs at the current loading on the resin's glass transition temperature or processability. However, the fire residues from cone calorimetry tests of the composites containing FRs were found to be only 15-20% of the thickness of the resins, implying a suppression of intumescence upon transfer. At room temperature, the decrease in the flexural modulus for the composites containing FRs was negligible. Exposure of the composites in a furnace at 400°C as a preliminary study before ignition tests was shown to cause significant flexural moduli reductions after 2.5 min of exposure and complete delamination after 3 min making further testing unviable. This study emphasizes the need for future research on recovering modes of action upon transfer of FR formulations from resins to composites. Based on the challenges outlined in this investigation, sample adaptation methods for post-fire analysis will be developed in a future study.
KW - DGEBA
KW - Prepregs
KW - Glass fiber-reinforced composites
KW - Post-fire testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605239
DO - https://doi.org/10.1002/pc.28416
SN - 1548-0569
SN - 0272-8397
VL - 45
IS - 10
SP - 9389
EP - 9406
PB - Wiley
AN - OPUS4-60523
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Serrano-Munoz, Itziar
A1 - Haubrich, Jan
A1 - Requena, Guillermo
A1 - Madia, Mauro
T1 - Investigation on the fatigue strength of AlSi10Mg fabricated by PBF-LB/M and subjected to low temperature heat treatments
N2 - This work provides an investigation of the influence of low temperature heat treatments on the fatigue behavior of a PBF-LB AlSi10Mg alloy. Fatigue specimens are produced in form of round bars on a build platform preheated at 200 ◦C. The specimens have been tested in three different conditions: as-built, and after heat treatments at 265 ◦C for 1 h and 300 ◦C for 2 h. Prior to the fatigue testing, the defect distribution is analyzed by means of micro computed tomography. Subsequently, the peak over threshold method is successfully applied to provide a prediction of the size of killer defect. The defect population was of gas porosity type. No clear improvement of the fatigue performance is observed after the heat treatments. The fatigue strength predicted using fracture mechanics-based approaches is in good agreement with the experimental data. Among the studied approaches, short crack models provided the most conservative predictions.
KW - PBF-LB/M AlSi10Mg
KW - Fatigue strength
KW - Defects
KW - Kitagawa-Takahashi Diagram
KW - Short Crack Models
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607071
DO - https://doi.org/10.1016/j.matdes.2024.113170
SN - 0264-1275
VL - 244
SP - 1
EP - 12
PB - Elsevier Ltd.
AN - OPUS4-60707
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sunder, S.
A1 - Jauregui Rozo, Maria
A1 - Inasu, S.
A1 - Schartel, Bernhard
A1 - Ruckdäschel, H.
T1 - Investigating the changing dynamics of processing, temperature-based mechanics, and flame retardancy in the transfer of ammonium polyphosphate/inorganic silicate flame retardants from epoxy resins to glass fiber composites
N2 - Although numerous investigations study the improvement of flame retardancy of epoxy resins using additives, maintaining the flame retardant (FRs) modes of action present in the resins upon transfer to composites is challenging. In this study, ammonium polyphosphate (APP) and inorganic silicate (InSi) are loaded at 10%, 30%, and 50% by weight, in a diglycidyl ether of bisphenol A (DGEBA) resin cured with dicyandiamide and transferred to bidirectional (BD) glass fiber (GF) composites. Although a 50% loading of the FRs impacts the curing kinetics of the resin system, the effect on the glass transition temperature of the resin system remains negligible compared to reactive FRs in the state of the art integrated into the resin's chemical structure. Increasing the FR content improved the heat release characteristics in both the resins and composites. However, the charring mode of action is completely suppressed in the formulation with 10% APP + InSi. A 30% concentration of the FRs restored the charring action in the composite and the GFs provide increased protective layer action upon transfer to the composites. This study highlights the importance of accounting for the changing dynamics related to processing and flame retardancy upon transferring FRs from resins to composites.
KW - Composites
KW - Flame retardance
KW - Resins
KW - Synthesis and processing techniques
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610484
DO - https://doi.org/10.1002/app.55988
SN - 1097-4628
VL - 141
IS - 39
SP - 1
EP - 18
PB - Wiley
CY - New York, NY
AN - OPUS4-61048
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hupp, Vitus
A1 - Schartel, Bernhard
A1 - Flothmeier, K.
A1 - Hartwig, A.
T1 - Pyrolysis and flammability of phosphorus based flame retardant pressure sensitive adhesives and adhesive tapes
N2 - Pressure-sensitive adhesive tapes are used in a variety of applications such as construction, aircrafts, railway vehicles, and ships, where flame retardancy is essential. Especially in these applications, phosphorus-based flame retardants are often chosen over halogenated ones due to their advantages in terms of toxicity. Although there are pressure-sensitive adhesives with phosphorus flame retardants available on the market, their flame-retardant modes of action and mechanisms are not entirely understood. This research article provides fundamental pyrolysis research of three phosphorus-based flame retardants that exhibit different mechanisms in a pressuresensitive adhesive matrix. The flame-retardants modes of action and mechanisms of a 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) derivate, an aryl phosphate, and a self-synthesized, covalently bonded DOPO derivate (copolymerized) are investigated. The blended DOPO derivate is volatilized at rather low temperatures while the covalently bonded DOPO derivate decomposes together with the polymer matrix at the same temperature. Both DOPO derivates release PO radicals which are known for their flame inhibition. The aryl phosphate decomposes at higher temperatures, releases small amounts of aryl phosphates into the gas phase, and acts predominantly the condensed phase. The aryl phosphate acts as precursor for phosphoric acid and improves the charring of the pressure sensitive adhesive matrix. All flame retardants enhance the flammability of the adhesives depending on their individual mode of action while the covalently bonded flame retardant additionally improves the mechanical properties at elevated temperatures making it a promising future technology for pressure-sensitive adhesives.
KW - Pyrolysis of flame retardant
KW - Pyrolysis gas chromatography
KW - Mass spectrometry
KW - Phosphorus flame retardant
KW - Decomposition mechanism
KW - Flame retardant pressure sensitive adhesives
KW - Flame retardancy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-607192
DO - https://doi.org/10.1016/j.jaap.2024.106658
SN - 0165-2370
SN - 1873-250X
VL - 181
SP - 1
EP - 31
PB - Elsevier B.V.
AN - OPUS4-60719
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Bauer, Felix
A1 - Uhlemann, Patrick
A1 - Thärig, Steffen
A1 - Rehmer, Birgit
A1 - Skrotzki, Birgit
T1 - Mechanical testing dataset of cast copper alloys for the purpose of digitalization
N2 - This data article presents a set of primary, analyzed, and digitalized mechanical testing datasets for nine copper alloys. The mechanical testing methods including the Brinell and Vickers hardness, tensile, stress relaxation, and low-cycle fatigue (LCF) testing were performed according to the DIN/ISO standards. The obtained primary testing data (84 files) mainly contain the raw measured data along with the testing metadata of the processes, materials, and testing machines. Five secondary datasets were also provided for each testing method by collecting the main meta- and measurement data from the primary data and the outputs of data analyses. These datasets give materials scientists beneficial data for comparative material selection analyses by clarifying the wide range of mechanical properties of copper alloys, including Brinell and Vickers hardness, yield and tensile strengths, elongation, reduction of area, relaxed and residual stresses, and LCF fatigue life. Furthermore, both the primary and secondary datasets were digitalized by the approach introduced in the research article entitled “Toward a digital materials mechanical testing lab” [1]. The resulting open-linked data are the machine-processable semantic descriptions of data and their generation processes and can be easily queried by semantic searches to enable advanced data-driven materials research.
KW - FAIR principles
KW - Hardness
KW - Low-Cycle Fatigue (LCF)
KW - Tensile testing
KW - Stress relaxation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-605005
DO - https://doi.org/10.1016/j.dib.2024.110687
SN - 2352-3409
SP - 1
EP - 15
PB - Elsevier BV
AN - OPUS4-60500
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nandish, Ranjith
A1 - Knaust, Christian
A1 - Hofmann-Böllinghaus, Anja
A1 - Gnutzmann, Tanja
A1 - Zehfuß, Jochen
T1 - Simulation of wood pyrolysis with component-based mechanism
N2 - This paper presents a comprehensive fire simulation study that models the pyrolysis process of beech wood using kinetic parameters with the Fire Dynamics Simulator (FDS). The kinetic methodology is based on the application of these kinetic parameters to govern the underlying pyrolysis reactions. The primary objective was to numerically model the pyrolysis process for beech wood using both single-component (single-step, single reaction scheme) and multi-component (single-step, multi-reaction scheme) kinetic reaction schemes. The accuracy of the numerical model was validated by comparing FDS simulation results with experimental data obtained from thermogravimetric analysis (TGA) and cone calorimeter tests. This approach aids in identifying reliable kinetic reaction input parameters for modelling wood fires. A case study was included to demonstrate the implementation of the kinetic reaction schemes. Numerical results from the TGA simulations for the small-scale pure cellulose test using the single-component approach exhibit consistency with the experimental data. Furthermore, the results demonstrated that the multi-component approach more accurately replicates the shape of the experimental curve for beech wood compared to the single-component approach. However, discrepancies in the tail regions of the curves obtained from the FDS simulations showed the need for further improvement in the modelling approach, particularly regarding the exclusion of char oxidation reactions, which needs to be investigated further.
KW - Simulation
KW - Wood
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639272
DO - https://doi.org/10.1007/s00231-025-03571-7
SN - 0947-7411
VL - 61
IS - 6
SP - 1
EP - 14
PB - Springer Science and Business Media LLC
AN - OPUS4-63927
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Piechnik, Kira
A1 - Heydick, Lukas
A1 - Hofmann-Böllinghaus, Anja
A1 - Klippel, Andrea
T1 - Comprehensive laboratory study on smoke gases during the thermal oxidative decomposition of forest and vegetation fuels
N2 - AbstractThis study investigates the composition of smoke gases in forest and vegetation samples to draw conclusions about the actual smoke gas composition during wildfires. The focus is particularly on regions with extensive pine forests, like in Eastern Germany. The relevance of smoke gases is well illustrated by the example of wildfires in Québec, influencing air quality in New York, in 2023. By employing a modified DIN tube furnace, a bench‐scale test set‐up, the research emphasizes the examination of smoke composition from tree species and ground cover, prioritizing gases while disregarding particles. Key smoke gases are identified as CO, CO2, SO2, HCN, C3H4O (acrolein) and CH2O (formaldehyde) and their concentrations are compared with Acute Exposure Guideline Levels (AEGL) limits. Acknowledging the limitations of AEGL usage and the problem with direct quantitative comparison of toxicant concentrations (cf. ISO 29903‐1:2020), the study highlights variations in smoke composition across different samples. The results of the studies reveal a significant disparity in CO concentration between dry and fresh pine needles. Frequently, the AEGLs of key gases are exceeded significantly. The elemental analysis of the barks indicates distinct differences in composition, reflecting in the concentrations of smoke gases. The ratio of 1 mole of substance turnover to the identified key components will be used to determine input parameters for the subsequent numerical simulation.
KW - Forest
KW - Wildfire
KW - Ignition
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-617744
DO - https://doi.org/10.1002/fam.3253
SP - 1
EP - 12
PB - Wiley online library
AN - OPUS4-61774
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Campari, Alessandro
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Alvaro, Antonio
T1 - A comparison of vintage and modern X65 pipeline steel using hollow specimen technique for in-situ hydrogen testing
N2 - The transition toward a hydrogen-based economy requires a widespread transport and distribution network, and repurposed natural gas pipelines are a viable option. An assessment of the hydrogen-induced degradation of pipeline steels is needed to inject H2 gas into the existing infrastructure safely. The conservative and standardized method consists of in-situ tensile tests in an autoclave filled with high-pressure hydrogen gas. A proposed alternative method involves
using a hollow specimen as containment volume and applying the gas pressure in the inner cavity.
This technique has lower costs and shorter test preparation time but is not standardized yet. This study aims to evaluate and compare the tensile properties of API 5L X65 pipeline steel in two states: vintage and modern. The influence of the surface roughness is investigated through parallel tests with drilled and reamed specimens. Hydrogen tests are compared with reference tests in an inert environment. A significant hydrogen-induced decrease in tensile properties is observed, and no significant difference between vintage and modern X65 can be drawn. The reduction in tensile properties is more significant in specimens with higher inner surface roughness. The evaluation of surface conditions appears crucial when assessing the HE susceptibility of hydrogen transport and storage equipment.
KW - Hydrogen embrittlement
KW - Hollow specimen technique
KW - Pipeline steel
KW - SSRT
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-603013
DO - https://doi.org/10.1016/j.engfailanal.2024.108530
VL - 163
SP - 1
EP - 15
PB - Elsevier Ltd.
AN - OPUS4-60301
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Konert, Florian
A1 - Nietzke, Jonathan
A1 - Grimault de Freitas, Tomás
A1 - Rhode, Michael
A1 - Sobol, Oded
A1 - Böllinghaus, Thomas
T1 - Investigation of resistance to gaseous hydrogen of a longitudinal weld seam in a X65 pipeline using the hollow specimen technique
N2 - The constantly increasing demand for renewable energy sources leads to the necessity of transporting large amounts of hydrogen. Since pipelines enable a cost-effective way for the distribution of gaseous hydrogen, the interaction of hydrogen and the pipeline materials must be carefully investigated as hydrogen can cause a degradation of the mechanical properties under certain conditions. Especially welds, which are assumed to be more susceptible to the degradation enhanced by hydrogen, are of great interest. The aim of this study is to investigate the effect of gaseous hydrogen on the mechanical properties of an X65 pipeline, and the longitudinal submerged arc welding (SAW) welded joint. The tests are conducted using the hollow specimen technique on two types of specimens: one extracted from the base material (BM) and the other extracted as a cross-weld (CW) specimen consisting of BM and weld seam. The specimens are charged in situ under a pressure of 60 bar and tested using slow strain rate (SSR) tensile tests with a nominal strain rate of 10−5 s−1. The properties obtained of specimens tested in hydrogen atmosphere are compared to the properties of comparable specimen in inert argon atmosphere as a reference. The performed tests showed a decrease of the reduction of area (RA) from 72% in inert atmosphere to 52% in hydrogen atmosphere for the CW specimen and a decrease from 73% in inert atmosphere to 51% for the BM. Metallographic analyses showed the crack initiation between fine-grained heat-affected zone (FGHAZ) and BM for the specimens tested in hydrogen atmosphere as well as for the reference specimens. This leads to the conclusion that the location of the crack initiation does not change due to the presence of gaseous hydrogen.
KW - Hydrogen
KW - Hollow specimen technique
KW - Pipeline
KW - SSRT
KW - Hydrogen embrittlement
KW - Cross-weld specimen
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-624658
DO - https://doi.org/10.1007/s40194-025-01953-3
SN - 0043-2288
SN - 1878-6669
VL - 69
IS - 3
SP - 861
EP - 870
PB - Springer
CY - Berlin
AN - OPUS4-62465
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Nietzke, Jonathan
A1 - Konert, Florian
A1 - Poka, Konstantin
A1 - Merz, Benjamin
A1 - Sobol, Oded
A1 - Böllinghaus, Thomas
T1 - Comparison of hydrogen effects on additively manufactured and conventional austenitic steels
N2 - Hydrogen and its derivatives are promising energy carriers for future renewable energy supplies. Austenitic stainless steels, such as AISI 316L, are commonly used in hydrogen transportation systems. While often thought to be resistant to hydrogen embrittlement, studies have shown that 316L is susceptible under certain conditions. As demand for hydrogen applications grows, additive manufacturing (AM) technologies offer design flexibility and customisation benefits. However, data on AM parts behaviour in hydrogen environments is lacking. This study investigates the influence of hydrogen on mechanical properties using slow strain rate testing (SSRT) on conventional AISI 304L, 316L and AM 316L specimens. The results indicate a greater effect of hydrogen on 304L compared to 316L, with AM 316L showing increased susceptibility. However, the ductility of AM 316L remains comparable to conventional 316L due to its initial ductility. The study provides insights into the performance of conventional and AM austenitic stainless steels in gaseous hydrogen environments.
KW - Slow strain rate testing
KW - Hollow specimen
KW - Hydrogen embrittlement
KW - Additive manufacturing
KW - Austenitic steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615919
DO - https://doi.org/10.1016/j.engfailanal.2024.109042
SN - 1350-6307
VL - 167
SP - 1
PB - Elsevier B.V.
AN - OPUS4-61591
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Campari, Alessandro
A1 - Konert, Florian
A1 - Razavi, Nima
A1 - Sobol, Oded
A1 - Alvaro, Antonio
T1 - Hydrogen-assisted cracking: A deep learning approach for fractographic analysis
N2 - Hydrogen handling equipment suffers from interaction with their operating environment, which degrades the mechanical properties and compromises component integrity. Hydrogen-assisted cracking is responsible for several industrial failures with potentially severe consequences. A thorough failure analysis can determine the failure mechanism, locate its origin, and identify possible root causes to avoid similar events in the future. Postmortem fractographic analysis can classify the fracture mode and determine whether the hydrogen-metal interaction contributed to the component’s breakdown. Experts in fracture classification identify characteristic marks and textural features by visual inspection to determine the failure mechanism. Although widely adopted, this process is time-consuming and influenced by subjective judgment and individual expertise. This study aims to automate fractographic analysis through advanced computer vision techniques. Different materials were tested in hydrogen atmospheres and inert environments, and their fracture surfaces were analyzed by scanning electron microscopy to create an extensive image dataset. A pre-trained Convolutional Neural Network was finetuned to accurately classify brittle and ductile fractures. In addition, Grad-CAM interpretability method was adopted to identify the image regions most influential in the model’s prediction and compare the saliency maps with expert annotations. This approach offered a reliable data-driven alternative to conventional fractographic analysis.
KW - Failure analysis
KW - Fractographic analysis
KW - Hydrogen embrittlement
KW - Material compatibility
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646610
DO - https://doi.org/10.1016/j.commatsci.2025.114366
SN - 0927-0256
VL - 262
SP - 1
EP - 16
PB - Elsevier Science
CY - Amsterdam [u.a.]
AN - OPUS4-64661
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shikomba, Nikanor
A1 - Böllinghaus, Thomas
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Blasón Gonzalez, Sergio
A1 - Ohijeagbon, Idehai Olayemi
A1 - Krafft, Eike
A1 - Staudt, Thorsten
T1 - Resistance of welded low-alloyed pressure vessel and pipeline steels in gaseous hydrogen
N2 - Green hydrogen has become an essential energy carrier to achieve a climate-neutral economy. The production, storage, transport and usage of green hydrogen require safe and sustainable facilities and systems. The present contribution provides a procedure guideline to investigate the compatibility of steel welds for pressurised gaseous hydrogen applications under quasi-static mechanical loads, utilising the slow strain rate test and hollow specimen technique. Exemplarily, a weld of the low-alloyed steel P355NL1 was investigated and compared to an X65 weld. The results indicate that the base metal exhibits a higher ductility than the weld metal for both steels. Generally, hydrogen-exposed specimens exhibited a reduced strain, as compared to reference specimens. The hydrogen degradation, evaluated by the hydrogen embrittlement index, was more pronounced in the weld metal compared to the base P355NL1 material, whereas the X65 exhibited a larger hydrogen degradation of the base material than in the weld metal. Fractographic analysis of the test specimens revealed that hydrogen causes a transition from ductile to brittle features. Generally, the results of this study indicate a mild but significant degradation of the mechanical properties in terms of the ductility of the welds in the respective pressurised hydrogen atmosphere.
KW - Hydrogen-assisted cracking
KW - Welded joint
KW - Slow strain rate test
KW - Hollow Specimen
KW - Structural steel
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634138
DO - https://doi.org/10.1007/s40194-025-02074-7
SN - 0043-2288
SP - 1
EP - 15
PB - Springer
CY - Berlin
AN - OPUS4-63413
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grimault de Freitas, Tomás
A1 - Konert, Florian
A1 - Nietzke, Jonathan
A1 - Krzysch, Zephanja
A1 - Böllinghaus, Thomas
A1 - Michler, Thorsten
A1 - Wackermann, Ken
A1 - Oesterlin, Heiner
A1 - Tlili, Mohamed
A1 - Ruchti, Peter
A1 - Beitelschmidt, Denise
A1 - Elsen-Humberg, Stephan
A1 - Koenigs, Timo
A1 - Systermans, Thomas
A1 - Sobol, Oded
T1 - Tensile testing in high-pressure gaseous hydrogen using the hollow specimen method
N2 - Metallic materials, predominantly steels, are the most common structural materials in the various components along the hydrogen supply chain. Ensuring their sustainable and safe use in hydrogen technologies is a key factor in the ramp-up of the hydrogen economy. This requires extensive materials qualification, however, most of the accepted; and standardized test methods for determining the influence of gaseous hydrogen on metallic materials describe complex and costly procedures that are only available to a very limited extent worldwide. The hollow specimen technique is a simple, rapid, and economical method designed to overcome the limitations of the current methods for the qualification of metallic materials under high-pressure hydrogen gas. However, this technique is not yet standardized. The TransHyDE-H2Hohlzug project is presented in this article, along with the main steps required to optimize the hollow specimen technique. This includes closing knowledge gaps related to the specimen geometry, surface quality, and gas purity in dedicated working packages, thus contributing to a comprehensive standardization of the technique for tests in high-pressure hydrogen gas.
KW - High-pressure Gaseous Hydrogen
KW - Hydrogen Embrittlement
KW - Tensile Testing
KW - Hollow Specimen Technique
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610557
DO - https://doi.org/10.1557/s43577-024-00776-9
VL - 49
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-61055
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Müller, Simon
A1 - Hofmann-Böllinghaus, Anja
A1 - Chen, Zhimin
A1 - Vogel, Kristin
A1 - Benner, Philipp
T1 - A high-resolution spatiotemporal wildfire propagation dataset for the Mediterranean and Europe
N2 - Wildfires are becoming more frequent and severe under the influence of climate change, posing increasing risks to ecosystems, human health, and infrastructure. Accurate spatiotemporal data on wildfire propagation is essential for advancing fire behavior modeling, improving management strategies, and mitigating future impacts. However, existing datasets with both high spatial and temporal resolution are rare, costly, and time-consuming to produce. To address this gap, we present FireSpread_MedEU, a dataset comprising 320 consecutive burned area maps from 103 wildfire events across the Mediterranean and Europe between 2017 and 2023. Burned areas were derived from high-resolution Planet optical satellite imagery (~3 m spatial, mostly daily temporal resolution) using a semi-automated workflow, followed by manual refinement to ensure highest accuracy. Each dataset entry is enriched with detailed metadata and a subjective quality assessment. With its high level of spatiotemporal precision, FireSpread_MedEU provides essential data for the development and validation of machine learning models or wildfire simulation models. It opens new research opportunities in wildfire behavior analysis, risk assessment, and predictive modeling.
KW - Wildfire
KW - Remote Sensing
KW - Data
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-657294
DO - https://doi.org/10.1038/s41597-026-06965-2
SN - 2052-4463
VL - 13
IS - 1
SP - 1
EP - 7
PB - Springer Science and Business Media LLC
AN - OPUS4-65729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Röhsler, Andreas
A1 - Sobol, Oded
A1 - Unger, Wolfgang
A1 - Böllinghaus, Thomas
T1 - Comprehensive study of deuterium-induced effects in in austenitic stainless steel AISI 304L
N2 - The damaging impact of hydrogen on the austenitic stainless steel AISI 304 L was analysed.
To this aim, samples were charged electrochemically with the hydrogen isotope deuterium (2H, D) and examined with time-of-flight secondary ion mass spectrometry (ToF-SIMS) and electron backscatter diffraction (EBSD). The fusion of the obtained chemical and structural information revealed local enrichment of deuterium in austenite, transformation into martensite, crack formation and severe roughening of the specimen surface. The results indicated that martensite was not only formed during charging but also during Desorption and ToF-SIMS examinations. Furthermore, cross-sections of deuterium-charged samples revealed that in preferred deformation bands a g/ε/a 0 evolution is taking place.
By means of microscopic analyses and carrier gas hot extraction (CGHE), it was found that the use of NaAsO2 as recombination poison decreased the uptake of hydrogen significantly and resulted in severe precipitation on the specimen surfaces. This is in contrast to the popular presumption that NaAsO2 enhances the uptake of hydrogen (and
deuterium) during electrochemical charging by hampering its recombination from Atoms to molecules.
KW - AISI 304L
KW - Hydrogen
KW - ToF-SIMS
KW - Deuterium
KW - Martensite
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477540
DO - https://doi.org/10.1016/j.ijhydene.2019.03.058
SN - 0360-3199
SN - 1879-3487
VL - 44
IS - 23
SP - 12228
EP - 12238
PB - Elsevier Ltd.
AN - OPUS4-47754
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böllinghaus, Thomas
A1 - Lüders, V.
A1 - Nolze, Gert
T1 - Microstructural insights into natural silver wires
N2 - Due to the increasing global demand for pure silver, native wire silver aggregates in very high purities are gaining more industrial attention. Up to the present, no substantial metallurgical Investigation of natural wire silver exists in the accessible literature. To convey urgently needed cross-disciplinary fundamental knowledge for geoscientists and metallurgical engineers, twenty natural wire silver specimens from eight different ore deposits have been investigated in detail for the first time by EBSD (Electron Back Scattering Diffraction), supported by light microscopy and micro-probe analyses. The improved understanding of the natural silver wire microstructure provides additional Information regarding the growth of natural silver aggregates in comparison to undesired artificial growth on electronic devices. Clear evidence is provided that natural silver curls and hairs exhibit a polycrystalline face-centered cubic microstructure associated with significant twinning. Although the investigated natural wire silver samples have relatively high purity (Ag > 99.7 wt.-%), they contain a variety of trace elements such as, S, Cu, Mn, Ni, Zn, Co and Bi, As and Sb. Additionally, Vickers micro-hardness measurements are provided for the first time which revealed that natural silver wires and curls are softer than it might be expected from conversion of the general Mohs hardness of 2.7.
KW - Natural silver wires
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-451655
UR - http://www.nature.com/articles/s41598-018-27159-w
DO - https://doi.org/10.1038/s41598-018-27159-w
SN - 2045-2322
VL - 8
IS - 1
SP - Article 9053, 1
EP - 9
PB - nature publishing group
CY - London, United Kingdom
AN - OPUS4-45165
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Pfennig, Anja
A1 - Wolf, Marcus
A1 - Gröber, Andre
A1 - Böllinghaus, Thomas
A1 - Kranzmann, Axel
T1 - Corrosion fatigue of 1.4542 exposed to a laboratory saline aquifer water CCS-environment
N2 - X5CrNiCuNb16-4 has been proven to be sufficient resistant in corrosive environments, but shows rather unusual corrosion behaviour in CCS environment. Therefore a series of 30 specimens was tested at stress amplitudes between 150 MPa and 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ∼ 30 Hz). Due to the rather heterogeneous fine machined surfaces (Rz=4) the specimens are comparable with prefabricated parts. X5CrNiCuNb16-4 reached the maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa and lies 60% below the stress amplitude measured in air. The scatter range TN = 1:34 is disproportionately large. Although the fracture surface exhibited the typical striations and corroded surface areas no significant differences were found. The hardness was found to be homogeneous in all specimens tested at 335 HV10. Non-metallic inclusions were found within the microstructure, but no correlation could be found between the inclusions and early rupture. Still specimens that showed inclusions at the fracture surface and its cross section endured lower number of cycles. Additionally Aluminium was analysed in specimens with low number of cycles and may be cause for early rupture during corrosion fatigue tests. These findings reveal a very high sensitivity on a homogeneous microstructure upon the corrosion and corrosion fatigue behaviour of X5CrNiCuNb16-4 and needs to be taken into account when regarding this steel as pipe steel during injection of CO2 into saline aquifers.
T2 - 13th International Conference on Greenhouse Gas Control Technologies
CY - Lausanne, Switzerland
DA - 14.11.2016
KW - Steel
KW - Corrosion fatigue
KW - Electrochemistry
KW - Reliability
KW - CCS
KW - CO2-storage
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418525
DO - https://doi.org/10.1016/j.egypro.2017.03.1678
SN - 1876-6102
VL - 114
SP - 5219
EP - 5228
AN - OPUS4-41852
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wolf, Marcus
A1 - Afanasiev, Roman
A1 - Böllinghaus, Thomas
A1 - Pfennig, A.
T1 - Investigation of Corrosion Fatigue of Duplex Steel X2CrNiMoN22-5 3 Exposed to a Geothermal Environment under Different Electrochemical Conditions and Load Types
N2 - Corrosion fatigue (CF) of duplex stainless steel (DSS) X2CrNiMoN22-5-3 was investigated in in-situ geothermal conditions of the Northern German Basin (NGB). The influence of the load type on CF behavior of the alloy was examined by applying push/pull and rotating bending cyclic load to failure. The hour-glass shaped specimens with both polished and precisely turned surface finish were tested in corrosion chambers allowing for the permanent circulation of Northern German Basin electrolyte heated to 369 K. Additionally, the influence of a protective cathodic potential on the CF life expectancy was investigated by employing a potentiostat. The rotating bending cyclic load led to a higher CF life expectancy, which decreased with increasing duration of the experiment due to a higher deterioration rate of the material. The application of a cathodic potential caused a significant increase of the CF lifespan from 4.7 x 105 (open-circuit potential (OCP)) to 107 cycles (preset threshold cycle number) for the potential range from USHE = – 450 to – 900 mV. Microstructural analysis of the CF damage revealed horizontal grain attack within corrosion pit cavities, multiple fatigue cracks and preferable deterioration of the austenitic phase.
T2 - 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13
CY - Lausanne, Switzerland
DA - 14.11.2016
KW - Different load cases
KW - Corrosion fatigue
KW - DSS
KW - Geothermal environment
KW - Different electrochemical conditions
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-439231
DO - https://doi.org/10.1016/j.egypro.2017.03.1657
SN - 1876-6102
VL - 114
SP - 5337
EP - 5345
PB - Elsevier Science
AN - OPUS4-43923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geoerg, Paul
A1 - Polzin, Robert Malte
A1 - Schumann, Jette
A1 - Holl, Stefan
A1 - Hofmann-Böllinghaus, Anja
T1 - Small-scale studies on evacuation characteristics of pedestrians with physical, mental or age-related disabilities
N2 - Evaluation of evacuation process is common separated by two phases: pre-movement and movement-phase. Individual capabilities of pedestrians have an impact on both and therefore on the time required for safe escape. In view of evaluating the evacuation process, characteristics of realistic movements of pedestrians involved are needed, but so far such data are mainly available for individuals with unrestricted evacuation capabilities only.
Due to the lack of available data, parameter studies in an assisted living for people with disabilities were performed to explore the movement during evacuation. Preparation times for assistance (n = 10), unimpeded walking speeds (n = 34) depending on the assistance devices in the plane as well as walking speeds on stairs (n = 11) were focussed.
Time to prepare an assistance device for utilisation depends significantly on the kind of device type. Further on, practical experience in handling the devices for assistance has an impact on the preparation time. In contrast to the results of the preparation times, any relation on assistance devices were investigated for the unimpeded walking speed in the plane. A remarkable decrease of walking speed on stairs was observed which is independent from the utilised assistance device.
The presented data improve and extend the insufficient engineering data base and raised up questions regarding the complexity of considering pedestrians movement with impairments in evacuation planning.
T2 - 3rd European Symposium on Fire Safety Science
CY - Nancy, France
DA - 12.09.2018
KW - Human behaviour
KW - Egress
KW - Evacuation
KW - Pedestrians with disabilities
KW - Engineering data
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-466463
DO - https://doi.org/10.1088/1742-6596/1107/7/072006
SN - 1742-6596
VL - 1107
IS - 072006
SP - 1
EP - 6
PB - IOP Publ.
CY - Bristol
AN - OPUS4-46646
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geoerg, Paul
A1 - Schumann, Jette
A1 - Holl, Stefan
A1 - Holl, Maik
A1 - Hofmann-Böllinghaus, Anja
T1 - The influence of individual impairments in crowd dynamics
N2 - The importance of empirical relations to quantify the movement of pedestrians through a facility has increased during the last decades since performance-based design methods became more common. Bottlenecks are of special interest because of their importance for egress routes and as they result in a reduced capacity. The empirical relations as the density-dependent movement speed or flow rate were derived by studies under laboratory conditions, which were usually conducted with populations of homogeneous characteristics forbetter control of influencing variables.
If individual characteristics of a crowd become more heterogeneous, individuals were forced to adapt their individual movement and control individual manoeuvring.
These unintended interactions lead to a different shape of the fundamental empirical relations. Here, we present results from a movement study under well-controlled boundary conditions in which participants with and without different characteristics of disabilities participated. To consider the effect of different heterogeneities on the capacity of a facility, fundamental diagrams are generated using the Voronoi method. If participants with visible disabilities (such as using assistive devices) are part of a crowd, significant differences relating to the shape of the empirical Relations and the capacities are found. This indicates that the heterogeneity of a Population leads to an increased interpersonal interaction which results in influenced movement characteristics.
KW - Engineering egress data
KW - Heterogeneity
KW - Human behaviour
KW - Movement characteristics
KW - Pedestrian dynamics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-508943
DO - https://doi.org/10.1002/fam.2789
SN - 0308-0501
VL - 45
IS - 4
SP - 529
EP - 542
PB - Wiley Online Libary
CY - New Jersey, USA
AN - OPUS4-50894
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - An, Biwen Annie
A1 - Deland, Eric
A1 - Sobol, Oded
A1 - Yao, Jizheng
A1 - Skovhus, T. L.
A1 - Koerdt, Andrea
T1 - The differences in the corrosion product compositions of Methanogen-induced microbiologically influenced corrosion (Mi-MIC) between static and dynamic growth conditions
N2 - Currently, corrosion rates (CR) and/or corrosion products (CP) obtained for methanogen-induced microbiologically influenced corrosion (Mi-MIC) on carbon steel are mainly analyzed from static-incubations. By using a multiport-flow-column, much higher CRs (0.72 mm/yr) were observed, indicating static-incubations are not suitable for determining the corrosive potential of Mi-MIC. With the combination of various analytical methods (ToF-SIMS/SEM-EDS/SEM-FIB) and contrary to previously published data, we observed that CPs contained phosphorus, oxygen, magnesium, calcium and iron but lacked carbon-related species (e.g. siderite). Overall, siderite nucleation is disrupted by methanogens, as they convert aqueous bicarbonate into carbon dioxide for methanogenesis resulting in increased localized corrosion.
KW - Carbon steel
KW - Modelling studies
KW - SIMS
KW - SEM
KW - Reactor conditions
KW - Microbiologically influenced corrosion
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-517632
DO - https://doi.org/10.1016/j.corsci.2020.109179
SN - 0010-938X
VL - 180
SP - 9179
PB - Elsevier
AN - OPUS4-51763
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böllinghaus, Thomas
A1 - Wentland, Eva
A1 - Jaßmann, R.
A1 - Keller, R.
A1 - Wolfrum, Anne
T1 - Conservation of the Shaft #1 Headgear at the Tsumeb Mine, Namibia: Corrosion Protection
N2 - The Tsumeb Mine in Namibia represents one of the best-preserved mining sites in the world and is rapidly gaining cross-disciplinary interest among cultural and engineering scientists. Most of the open pit and the shaft mining equipment are still in place, including the ore processing units and the local power plant. The mining area thus deserves recognition as an industrial world heritage site, especially due to the rarity of such locations on the African continent. The Shaft #1 headgear, built in 1924, represents one of the oldest known riveted steel headgears of the Promnitz design worldwide. In contrast to similar steel structures located in the northern hemisphere, it has been exposed to a different rural semi-arid climate since it is located in the Otavi Mountain Land, characterized by semi-annual change of rainy and dry seasons. Parts of the Shaft #1 headgear have remained largely untouched for more than 70 years. Besides its outstanding heritage value, it thus also represents an interesting object for studying the composition of corrosion layers formed on mild steel surfaces when exposed to continental and industrial mining atmospheres. To find a suitable transparent corrosion prevention coating, various on-site coating samples were evaluated after 11 months of outdoor exposure, including Owatrol Oil®, which is based on natural oil and alkyd resin with strong wicking potential. The substance is frequently applied for the conservation of single components but is not yet widely used on large steel structures in the field of industrial heritage conservation. However, it represented the most stable anti-corrosion coating under the local atmospheric conditions in the on-site tests. Thus, the suitability of Owatrol Oil® as a transparent coating for corrosion protection of riveted mild steel structures in such climates was further investigated as a more recent approach for the conservation of large steel structures. Since the protective coatings are exposed to strong UV radiation in the local climate, the addition of a specific UV stabilizer mixture was also tested. For such laboratory tests, two mild steel samples were taken. The first one originated from a diagonal strut of the 1920s and the second one from a handrail mounted in the early 1960s. Using corresponding high-resolution scanning electron microscopy (HR-SEM) and energy-dispersive X-ray spectroscopy (EDX) it was found that the corrosion layers are predominantly composed of lepidocrocite and goethite. A weathering program simulating the specific environmental conditions at Tsumeb in a UV climate chamber was developed and the corrosion resistance of the mild steel surface was subsequently evaluated by potentiodynamic measurements. Such tests proved to be a fast and reliable procedure for ranking the corrosion resistance of the old mild steels. It was found that the long-term corrosion layers already provide significant protection against further corrosion in the simulated environment. However, the study also showed that this can be further improved by the application of the Owatrol Oil® as a protective coating that also seals crevices. The addition of the UV stabilizers, however, led to a significant deterioration in corrosion protection, even in comparison to that of the uncoated long-term corrosion layers on the surface. Regular overcoating seems more advisable for the long-term preservation of the Shaft #1 headgear than modifying the Owatrol Oil® Coating with the tested UV-stabilizing additives.
KW - Potentiodynamic measurements
KW - Mining head gear
KW - Mild steels
KW - Chemical composition
KW - Characterization of corrosion layers
KW - Alkyd resin-based coating
KW - UV-blocker addition
KW - Weathering tests
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-541476
DO - https://doi.org/10.1080/00393630.2021.2004007
SN - 0039-3630
SP - 1
EP - 15
PB - Taylor & Francis Online
AN - OPUS4-54147
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Röhsler, Andreas
A1 - Sobol, Oded
A1 - Hänninen, H.
A1 - Böllinghaus, Thomas
T1 - In-situ ToF-SIMS analyses of deuterium re-distribution in austenitic steel AISI 304L under mechanical load
N2 - Hydrocarbons fuel our economy. Furthermore, intermediate goods and consumer products are often hydrocarbon-based. Beside all the progress they made possible, hydrogen-containing substances can have severe detrimental effects on materials exposed to them. Hydrogen-assisted failure of iron alloys has been recognised more than a century ago. The present study aims to providing further insight into the degradation of the austenitic stainless steel AISI 304L (EN 1.4307) exposed to hydrogen. To this end, samples were electrochemically charged with the hydrogen isotope deuterium (2H, D) and analysed by scanning electron microscopy (SEM), electron back-scatter diffraction (EBSD) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). It was found that deuterium caused a phase transformation from the original γ austenite into ε- and α’-martensite. Despite their low solubility for hydrogen, viz. deuterium, the newly formed phases showed high deuterium concentration which was attributed to the increased density of traps. Information about the behaviour of deuterium in the material subjected to external mechanical load was gathered. A four-point-bending device was developed for this purpose. This allowed to analyse in-situ pre-charged samples in the ToF-SIMS during the application of external mechanical load. The results indicate a movement of deuterium towards the regions of highest stress.
KW - ToF-SIMS
KW - Hydrogen
KW - Deuterium
KW - AISI 304L
KW - EBSD
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-505142
DO - https://doi.org/10.1038/s41598-020-60370-2
VL - 10
IS - 1
SP - 3611
PB - Nature
AN - OPUS4-50514
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaupp, Thomas
A1 - Rhode, Michael
A1 - Yahyaoui, Hamza
A1 - Kannengießer, Thomas
ED - Lippold, J.
ED - Böllinghaus, Thomas
ED - Norrish, J.
ED - Scotti, A.
T1 - Hydrogen-assisted cracking in GMA welding of high-strength structural steels using the modified spray arc process
N2 - High-strength structural steels are used in machine, steel, and crane construction with yield strength up to 960 MPa. However, welding of these steels requires profound knowledge of three factors in terms of avoidance of hydrogen-assisted cracking (HAC): the interaction of microstructure, local stress/strain, and local hydrogen concentration. In addition to the three main factors, the used arc process is also important for the performance of the welded joint. In the past, the conventional transitional arc process (Conv. A) was mainly used for welding of high-strength steel grades. In the past decade, the so-called modified spray arc process (Mod. SA) has been increasingly used for welding production. This modified process enables reduced seam opening angles with increased deposition rates compared with the Conv. A. Economic benefits of using this arc type are a reduction of necessary weld beads and required filler material. In the present study, the susceptibility to HAC in the heat-affected zone (HAZ) of the high-strength structural steel S960QL was investigated with the externally loaded implant test. For that purpose, both Conv. A and Mod. SA were used with same heat input at different deposition rates. Both conducted test series showed same embrittlement index “EI” of 0.21 at diffusible hydrogen concentrations of 1.3 to 1.6 ml/100 g of arc weld metal. The fracture occurred in the HAZ or in the weld metal (WM). However, the test series withMod. SA showed a significant extension of the time to failure of several hours compared with tests carried out with Conv. A.
KW - High-strength steel
KW - GMA welding
KW - Diffusible hydrogen
KW - Implant test
KW - Fractography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515330
DO - https://doi.org/10.1007/s40194-020-00978-0
SN - 1878-6669
SN - 0043-2288
VL - 64
IS - 12
SP - 1997
EP - 2009
PB - Springer
CY - Berlin Heidelberg
AN - OPUS4-51533
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steiner, S.
A1 - Heldt, J.
A1 - Sobol, Oded
A1 - Unger, Wolfgang
A1 - Frömeling, T.
T1 - Influence of oxygen vacancies on core-shell formation in solid solutions of (Na,Bi)TiO3 and SrTiO3
N2 - Solid solutions of (Na,Bi)TiO3 (NBT) and SrTiO3 (ST) are materials of interest for high-strain or high-energy density capacitor applications. Often, they exhibit chemical heterogeneity and develop core-shell structures during regular solid-state synthesis with an NBT-rich core. In this case, the NBT forms first so that the strontium needs to diffuse into the material to reach chemical homogeneity. Depending on the presence of core-shell structures, the electrical properties can vary drastically. In this work, we rationalize the effect of variations in oxygen vacancy concentration by Fe-acceptor and Nb-donor doping. It can be shown that a diffusion couple of strontium and oxygen is responsible for chemical homogenization and that the oxygen vacancy content can control the formation of a core-shell structure.
KW - Lead-free ceramics
KW - Bismuth titanates
KW - Core-shell structures
KW - Diffusion/diffusivity
KW - Ferroelectricity/ferroelectric materials
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-525988
DO - https://doi.org/10.1111/jace.17845
SP - 1
EP - 10
PB - Wiley Periodicals LLC, John Wiley & Sons, Inc.
AN - OPUS4-52598
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wurzler, Nina
A1 - Sobol, Oded
A1 - Altmann, Korinna
A1 - Radnik, Jörg
A1 - Özcan Sandikcioglu, Özlem
T1 - Preconditioning of AISI 304 stainless steel surfaces in the presence of flavins—Part I: Effect on surface chemistry and corrosion behavior
N2 - Stainless steel AISI 304 surfaces were studied after a mild anodic polarization for oxide growth in the presence and absence of two derivatives of vitamin B2 (riboflavin and flavin mononucleotide) that can be secreted by metal‐reducing bacteria and act as a chelating agent for iron species. The alterations in oxide chemistry were studied by means of surface‐sensitive techniques such as X‐ray photoelectron spectroscopy and time‐of‐flight secondary ion mass spectrometry analysis. The complementary electrochemical characterization revealed a preferential growth of an oxide/hydroxide iron‐rich film that is responsible for an altered pit initiation and nucleation behavior. These findings suggest that as the corrosion behavior is determined by the interplay of the chemical and electronic properties, only a mild anodic polarization in the presence of redox‐active molecules is able to alter the chemical and electronic structure of the passive film formed on stainless steel AISI 304. This helps to achieve a profound understanding of the mechanisms of microbially influenced corrosion (MIC) and especially the possible effects of the redox‐active biomolecules, as they may play an important role in the corrosion susceptibility of stainless steel surfaces.
KW - Corrosion
KW - Stainless steel
KW - Surface analysis
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-528117
DO - https://doi.org/10.1002/maco.202012191
VL - 72
IS - 6
SP - 974
EP - 982
PB - Wiley
AN - OPUS4-52811
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Anderson, J.
A1 - Boström, L.
A1 - Chiva, R.
A1 - Guillaume, E.
A1 - Colwell, S.
A1 - Hofmann-Böllinghaus, Anja
A1 - Toth, P.
T1 - European approach to assess the fire performance of façades
N2 - Several attempts have been made in the past to develop a European harmonized testing and assessment method for façades before the European commission decided to publish a call for tender on the topic. A project consortium from five countries (Sweden, UK, France, Germany and Hungary) applied to the call for tender and was contracted to develop a European approach to assess the fire performance of façades. 24 sub-contractors and 14 stakeholder entities were part of the project. The objective of the European project was to address a request from the Standing Committee of Construction (SCC) to provide EC Member States regulators with a means to regulate the fire performance of façade systems based on a European Approach agreed by SCC. The initial stages of this Project were focused on establishing a Register of the regulatory requirements in all Member States in relation to the fire Performance of façade systems, and to identify those Member States who have regulatory requirements for the fire performance façade systems which go beyond the current EN 13501 (reaction to fire and fire resistance) classification systems and to collate the details of these additional requirements. After having confirmed the regulatory needs a testing and classification methodology based on BS 8414 and DIN 4102-20 was developed to address the identified key performance and classification characteristics.
This paper is a short overview of results the two-year development work, which Final Report published by the European Commission in 2018.
KW - Facade
KW - Regulation
KW - Testing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530501
DO - https://doi.org/10.1002/fam.2878
SN - 1099-1018
VL - 45(5)
IS - Special issue: Facade fire safety
SP - 598
EP - 608
PB - Wiley
CY - Oxford
AN - OPUS4-53050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hofmann-Böllinghaus, Anja
A1 - Klippel, Andrea
A1 - Gnutzmann, Tanja
A1 - Kaudelka, Sven
A1 - Rabe, Frederik
T1 - Influence of modern plastic furniture on the fire development in fires in homes: large-scale fire tests in living rooms
N2 - About 80% of all fire fatalities in Germany occur because of fires in homes. It has been known for some time that modern materials (synonym for materials consisting mostly of synthetic polymers) tend to burn differently from older materials (synonym for materials consisting mostly of fibrous cellulosic substances) and it has been acknowledged that the amount of combustible plastics in homes has increased significantly over the last decades. To investigate the influence of modern furniture and ventilation conditions of fires in homes, a series of four large-scale tests in two Living rooms (LRs) with adjacent rooms (ARs) was performed by BAM and the Frankfurt fire service. Two LRs, one with older furniture and one with modern furniture, were tested twice each. Each test started with the ignition of a paper cushion on an upholstered chair. The influence of modern materials on the fire development was investigated, as well as the influence of the ventilation on the fire development. In all settings, an upholstered chair was the first burning item. Results of the test series show that fires in rooms with modern furniture develop faster than fires in rooms with older furniture.
This is true for temperature development in the rooms as well as for smoke production.
KW - Room fire
KW - Furniture
KW - Modern
KW - Gas analysis
KW - Smoke
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527568
DO - https://doi.org/10.1002/fam.2934
VL - 45
IS - 1
SP - 155
EP - 166
PB - Wiley
CY - London
AN - OPUS4-52756
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Piechnik, Kira
A1 - Hofmann-Böllinghaus, Anja
A1 - Klippel, Andrea
T1 - Self‐ignition of forest soil samples demonstrated through hot storage tests
N2 - AbstractThe increasing threat of forest fires on a global scale is not only a matter of concern due to the potential harm they may cause to both human and animal life but also due to their significant role in exacerbating climate change. In light of these circumstances, one might inquire as to whether forest soil can self‐ignite and, if so, under what conditions and at what temperatures this phenomenon may occur. This question is being addressed in the German pilot “Fire science of wildfires and safety measures” of the EU project TREEADS, and the first results are presented below. The importance of basic research into the self‐ignition of forest soil cannot be underestimated, as it provides crucial knowledge to prevent forest fires and protect human and animal health. Furthermore, mitigating the occurrence of forest fires can also play a role in reducing greenhouse gas emissions, contributing to global efforts to combat climate change. The procedure of the hot storage test is an effective means of determining whether a material can self‐ignite. During the investigation of six soil samples, it was found that five of them were indeed capable of self‐ignition. In addition to determining whether the material ignites, the modified hot storage test also analyzed the resulting smoke gases and measured their concentration. The research question of whether regional forest soil is capable of self‐ignition can be answered with yes based on these initial tests. Further experiments are needed to determine if self‐ignition causes forest fires.
KW - FTIR
KW - Hot storage
KW - Ignition
KW - Soil
KW - Wildfire
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594617
DO - https://doi.org/10.1002/fam.3198
SN - 1099-1018
VL - 48
IS - 4
SP - 495
EP - 507
PB - Wiley
CY - New York, NY
AN - OPUS4-59461
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drexler, A.-K.
A1 - Konert, Florian
A1 - Nietzke, Jonathan
A1 - Hodžić, E.
A1 - Pastore, S.
A1 - Domitner, J.
A1 - Rhode, Michael
A1 - Sommitsch, C.
A1 - Böllinghaus, Thomas
T1 - Effect of Tensile Loading and Temperature on the Hydrogen Solubility of Steels at High Gas Pressure
N2 - The hydrogen solubility in ferritic and martensitic steels is affected by hydrostatic stress, pressure, and temperature. In general, compressive stresses decrease but tensile stresses increase the hydrogen solubility. This important aspect must be considered when qualifying materials for high‐pressure hydrogen applications (e.g., for pipelines or tanks) by using autoclave systems. In this work, a pressure equivalent for compensating the effect of compressive stresses on the hydrogen solubility inside of closed autoclaves is proposed to achieve solubilities that are equivalent to those in pipelines and tanks subjected to tensile stresses. Moreover, it is shown that the temperature effect becomes critical at low temperatures (e.g., under cryogenic conditions for storing liquid hydrogen). Trapping of hydrogen in the microstructure can increase the hydrogen solubility with decreasing temperature, having a solubility minimum at about room temperature. To demonstrate this effect, the generalized law of the hydrogen solubility is parameterized for different steels using measured contents of gaseous hydrogen. The constant parameter sets are verified and critically discussed with respect to the high‐pressure hydrogen experiments.
KW - Hydrogen
KW - Solubility
KW - Temperature
KW - Tensile loading
KW - Analytical calculation
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-586701
DO - https://doi.org/10.1002/srin.202300493
SN - 1611-3683
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-58670
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manes, M.
A1 - El Houssami, M.
A1 - Campbell, R.
A1 - Sauca, A.
A1 - Rush, D.
A1 - Hofmann-Böllinghaus, Anja
A1 - Andersson, P.
A1 - Wagner, P.
A1 - Veeneklaas, J.
A1 - van Hees, P.
A1 - Guillaume, E.
T1 - Closing Data Gaps and Paving the Way for Pan-European Fire Safety Efforts: Part I—Overview of Current Practices for Fire Statistics
N2 - The analysis of the current state of fire statistics and data collection in Europe and other countries is needed to increase awareness of how fire incidents affect buildings and to support pan-European fire prevention and fire mitigation measures.
The terminology and data collected regarding fire incidents in buildings in the EU Member States were mapped to obtain meaningful datasets to determine common terminology, collection methodology, and data interpretation system. An extensive literature review showed that fire data collection systems have been instrumental in informing firefighting strategies, evidence-based planning, prevention, and educational programmes. Differences and similarities between fire data collection systems were also investigated. The amount and quality of the information in fire statistical recording systems appear to be influenced by the complexity and structure with which the data are collected. The analysis also examined the existing fire statistics in the EU Member States and a few other countries. Finally, a detailed investigation of the number of fires, fire deaths, and injuries from 2009 to 2018 in several countries was examined based on data from a report by CTIF. The trends showed differences attributable to the existing fire statistical practices in terms of terminology and data
collection, and interpretation. Part II proposes a common terminology for selected fire statistical variables. The results provide relevant information regarding fire safety at the European level and should be used to guide the development of more uniform fire statistics across Europe.
KW - Fire statistics
KW - European project
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575711
DO - https://doi.org/10.1007/s10694-023-01415-6
SN - 1572-8099
SP - 1
EP - 44
PB - Springer
CY - Heidelberg
AN - OPUS4-57571
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Houssami, M.
A1 - Försth, M.
A1 - Fredriksson, H.
A1 - Drean, V.
A1 - Guillaume, E.
A1 - Hofmann-Böllinghaus, Anja
A1 - Sandinge, A.
T1 - Fire safety of interior materials of buses
N2 - This study provides an analysis on the fire safety of passengers and the fire protection of coaches and buses. A brief review of major bus fire incidents, an overview of current regulations in Europe, and their limitations are presented. The study finds that the current small-scale fire test methods described in UN ECE Reg No. 118 need to be replaced by test methods that can assess the reaction to fire of materials when exposed to ignition sources of varying sizes. To address these shortcomings, the study proposed an expert recommendation to update the material fire safety requirements and testing for buses. Additional measures are proposed, derived from objectives and strategies applied in other transport sectors, and can be tested through existing European and international standards, which are widely used by several industries. These measures aim to extend the time with tenable conditions for a safe evacuation in case of fire, reduce the degree of damage to buses, reduce the risk for fast and excessive thermal exposure on modern energy carriers needed for a more sustainable transport sector.
KW - Fire
KW - Bus interior materials
KW - Rregulations
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575700
DO - https://doi.org/10.1002/fam.3134
SN - 1099-1018
SP - 1
EP - 15
PB - Wiley
CY - London
AN - OPUS4-57570
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Konert, Florian
A1 - Campari, Alessandro
A1 - Nietzke, Jonathan
A1 - Sobol, Oded
A1 - Paltrinieri, Nicola
A1 - Alvaro, Antonio
T1 - Evaluation of the tensile properties of X65 pipeline steel in compressed gaseous hydrogen using hollow specimens
N2 - Hydrogen has great potential on the path towards decarbonization of the energy and transport sectors and can mitigate the urgent issue of global warming. It can be sustainably produced through water electrolysis with potentially zero emissions, and efficiently used (e.g., in fuel cell systems). Despite its environmental advantages, hydrogen-metal interactions could result in the degradation of the mechanical properties of several structural materials. In order to determine the magnitude of the material degradation in relation to hydrogen exposure, extensive material testing is required. The standardized procedure for in-situ testing for the quantification of the impact of compressed gaseous hydrogen (CGH2) relies on the utilization of an autoclave around the tested specimen. Such test set-up is complex, expensive, time-consuming and requires special equipment, trained personnel, and strict safety procedures. A relatively recent method to circumvent these issues and provide affordable results consists of using hollow specimens, thus applying the hydrogen pressure inside rather than outside the specimen. It allows to reduce the volume of hydrogen by several orders of magnitude and to perform the tests more efficiently and in a safer manner. This study focuses on evaluating the tensile properties of X65 vintage pipeline steel tested in a high-pressure hydrogen environment using hollow specimens. Tests are performed in 6 MPa H2 and Ar at the nominal strain rate of 10−6 s−1 to evaluate the reduced area at fracture and the elongation loss. The effect of surface finishing on crack initiation and propagation is investigated by comparing two different manufacturing techniques. In this way, this study provides insights into the applicability of a novel, reliable, and safe testing method which can be used to assess the hydrogen-assisted ductility loss in metallic materials.
KW - Mechanical Engineering
KW - Hydrogen Embrittlement
KW - SSRT
KW - Hollow specimen
KW - Pipeline steel
KW - In-situ tensile test
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595887
DO - https://doi.org/10.1016/j.prostr.2024.01.074
SN - 2452-3216
VL - 54
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-59588
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Konert, Florian
A1 - Wieder, Frank
A1 - Nietzke, Jonathan
A1 - Meinel, Dietmar
A1 - Böllinghaus, Thomas
A1 - Sobol, Oded
T1 - Evaluation of the impact of gaseous hydrogen on pipeline steels utilizing hollow specimen technique and μCT
N2 - The high potential of hydrogen as a key factor on the pathway towards a climate neutral economy, leads to rising demand in technical applications, where gaseous hydrogen is used. For several metals, hydrogen-metal interactions could cause a degradation of the material properties. This is especially valid for low carbon and highstrength structural steels, as they are commonly used in natural gas pipelines and analyzed in this work.
This work provides an insight to the impact of hydrogen on the mechanical properties of an API 5L X65 pipeline steel tested in 60 bar gaseous hydrogen atmosphere. The analyses were performed using the hollow specimen technique with slow strain rate testing (SSRT). The nature of the crack was visualized thereafter utilizing μCT imaging of the sample pressurized with gaseous hydrogen in comparison to one tested in an inert atmosphere.
The combination of the results from non-conventional mechanical testing procedures and nondestructive imaging techniques has shown unambiguously how the exposure to hydrogen under realistic service pressure influences the mechanical properties of the material and the appearance of failure.
KW - Energy Engineering and Power Technology
KW - Condensed Matter Physics
KW - Fuel Technology
KW - Renewable Energy, Sustainability and the Environment
KW - µCT
KW - Hollow Specimen Technique
KW - Hydrogen Embrittlement
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595077
DO - https://doi.org/10.1016/j.ijhydene.2024.02.005
SN - 0360-3199
VL - 59
SP - 874
EP - 879
PB - Elsevier B.V.
AN - OPUS4-59507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Manes, M.
A1 - Sauca, A.
A1 - El Houssami, M.
A1 - Andersson, P.
A1 - McIntyre, C.
A1 - Campbell, R.
A1 - Rush, D.
A1 - Hofmann-Böllinghaus, Anja
A1 - Wagner, P.
A1 - Leene, M.
A1 - Oberhagemann, D.
A1 - Jomaas, G.
A1 - Grone, F.
A1 - Guillaume, E.
T1 - Closing Data Gaps and Paving the Way for Pan-European Fire Safety Efforts: Part II—Terminology of Fire Statistical Variables
N2 - A well-defined terminology of fire-related variables is important for correct analyses and supporting knowledge-based decisions regarding the evaluation of building fires at the European level. After developing an overview of current practices for fire statistics in Part I, the terminology used and the data collected by the EU Member States and eight other countries regarding fire incidents, property damage and human losses were mapped to increase awareness of their practice and support a comprehensive assessment of several fire statistical datasets. A questionnaire was distributed to relevant authorities responsible for the collection, elaboration/analysis, and fire statistical data publications to define and select the essential variables for an appropriate fire assessment and fire incident description. Based on the results of the questionnaire able to identify the essential fire statistical variables and a detailed analysis of current definitions adopted in the fire statistics of the EU Member States and other countries, a common terminology is proposed to collect the necessary data in the EU Member States and obtain meaningful datasets based on standardised terms and definitions. The results will generate essential outputs to move towards harmonised fire statistics at the EU level and contribute to an appropriate analysis able to improve fire prevention and fire mitigation in building fires.
KW - Fire statistics
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-575725
DO - https://doi.org/10.1007/s10694-023-01408-5
SN - 1572-8099
SP - 1
EP - 32
PB - Springer
CY - Heidelberg
AN - OPUS4-57572
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klippel, A.
A1 - Hofmann-Böllinghaus, Anja
A1 - Gnutzmann, Tanja
A1 - Piechnik, K.
T1 - Reaction-to-fire testing of bus interior materials: Assessing burning behaviour and smoke gas toxicity
N2 - Although fire safety regulations for buses have been adapted in recent years regarding, for example, fire detection and engine fire suppression systems, the changes in regulations for bus interior materials are minimal. A comparison of fire safety regulations for interior materials in other transport sectors for trains, ships or aircraft reveals a much lower level of requirements for bus materials. Although repeated bus accidents as well as fire statistics show the danger a bus fire can pose to passengers.
In particular, the combination of a fire incident and passengers with reduced mobility led to severe disasters in Germany and other European countries. To enhance the fire safety for passengers, the interior bus materials are crucial as the fire development in the bus cabin determines whether escape and rescue is possible. Against this background, bus interior materials were tested in different fire test scenarios. Measurement of a wide variety of parameters, for example, the mass loss, ignition time, smoke gas composition, heat release rate among others were carried out. Tested materials complied to the newest set of requirements. For this purpose, interior materials and their components had to be identified according to their chemical structure. Parts of the tests were funded by BASt (Federal Highway Research Institute) in the project 82.0723/2018. Experimental results show reaction-to-fire behaviour which lead to very limited times for escape and rescue in case of fire in a bus cabin. Based on the studies on fire behaviour and toxicity assessment, recommendations for improved fire safety regulations for interior materials could be made.
KW - Burning behaviour
KW - Bus interior materials
KW - Cone calorimeter
KW - DIN tube furnace
KW - FTIR spectroscopy
KW - Reference values
KW - Smoke toxicity
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-576085
DO - https://doi.org/10.1002/fam.3108
SN - 1099-1018
VL - 47
IS - 5
SP - 665
EP - 680
PB - Wiley
CY - New York, NY
AN - OPUS4-57608
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böllinghaus, Thomas
A1 - Cross, Carl
T1 - Obituary: Prof. Dr.-Ing. Hans Hoffmeister
N2 - On November 3, 2023, our dear colleague, Prof. Dr.-Ing. Hans Hoffmeister, born in 1932 in Kassel, Germany, passed away in Ahrensburg, near Hamburg, Germany.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594160
DO - https://doi.org/10.1007/s40194-023-01675-4
SP - 1
EP - 2
PB - Springer Science and Business Media LLC
AN - OPUS4-59416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Waitelonis, Jörg
A1 - Birkholz, Henk
A1 - Jung, Matthias
A1 - Schilling, Markus
A1 - v. Hartrott, Philipp
A1 - Bruns, Marian
A1 - Schaarschmidt, Jörg
A1 - Beilke, Kristian
A1 - Mutz, Marcel
A1 - Nebel, Vincent
A1 - Königer, Veit
A1 - Beran, Lisa
A1 - Kraus, Tobias
A1 - Vyas, Akhilesh
A1 - Vogt, Lars
A1 - Blum, Moritz
A1 - Ell, Basil
A1 - Chen, Ya‐Fan
A1 - Waurischk, Tina
A1 - Thomas, Akhil
A1 - Durmaz, Ali Riza
A1 - Ben Hassine, Sahar
A1 - Fresemann, Carina
A1 - Dziwis, Gordian
A1 - Beygi Nasrabadi, Hossein
A1 - Hanke, Thomas
A1 - Telong, Melissa
A1 - Pirskawetz, Stephan
A1 - Kamal, Mohamed
A1 - Bjarsch, Thomas
A1 - Pähler, Ursula
A1 - Hofmann, Peter
A1 - Leemhuis, Mena
A1 - Özçep, Özgür L.
A1 - Meyer, Lars‐Peter
A1 - Skrotzki, Birgit
A1 - Neugebauer, Jörg
A1 - Wenzel, Wolfgang
A1 - Sack, Harald
A1 - Eberl, Chris
A1 - Portella, Pedro Dolabella
A1 - Hickel, Tilmann
A1 - Mädler, Lutz
A1 - Gumbsch, Peter
T1 - Concepts for a Semantically Accessible Materials Data Space: Overview over Specific Implementations in Materials Science
N2 - This article describes advancements in the ongoing digital transformation in materials science and engineering. It is driven by domain‐specific successes and the development of specialized digital data spaces. There is an evident and increasing need for standardization across various subdomains to support science data exchange across entities. The MaterialDigital Initiative, funded by the German Federal Ministry of Education and Research, takes on a key role in this context, fostering collaborative efforts to establish a unified materials data space. The implementation of digital workflows and Semantic Web technologies, such as ontologies and knowledge graphs, facilitates the semantic integration of heterogeneous data and tools at multiple scales. Central to this effort is the prototyping of a knowledge graph that employs application ontologies tailored to specific data domains, thereby enhancing semantic interoperability. The collaborative approach of the Initiative's community provides significant support infrastructure for understanding and implementing standardized data structures, enhancing the efficiency of data‐driven processes in materials development and discovery. Insights and methodologies developed via the MaterialDigital Initiative emphasize the transformative potential of ontology‐based approaches in materials science, paving the way toward simplified integration into a unified, consolidated data space of high value.
KW - Semantic Interoperability
KW - Data Spaces
KW - Integration Workflows
KW - MaterialDigital
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-622952
DO - https://doi.org/10.1002/adem.202401092
SN - 1527-2648
SP - 1
EP - 25
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-62295
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rehmer, Birgit
A1 - Bayram, Faruk
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Skrotzki, Birgit
T1 - Elastic modulus data for additively and conventionally manufactured variants of Ti-6Al-4V, IN718 and AISI 316 L
N2 - This article reports temperature-dependent elastic properties (Young’s modulus, shear modulus) of three alloys measured by the dynamic resonance method. The alloys Ti-6Al-4V, Inconel IN718, and AISI 316 L were each investigated in a variant produced by an additive manufacturing processing route and by a conventional manufacturing processing route. The datasets include information on processing routes and parameters, heat treatments, grain size, specimen dimensions, and weight, as well as Young’s and shear modulus along with their measurement uncertainty. The process routes and methods are described in detail. The datasets were generated in an accredited testing lab, audited as BAM reference data, and are hosted in the open data repository Zenodo. Possible data usages include the verification of the correctness of the test setup via Young’s modulus comparison in low-cycle fatigue (LCF) or thermo-mechanical fatigue (TMF) testing campaigns, the design auf VHCF specimens and the use as input data for simulation purposes.
KW - Elastic modulus
KW - Young's modulus
KW - Shear modulus
KW - Additive manufacturing
KW - AISI 316L
KW - IN 718
KW - Ti-6Al-4V
KW - Reference data
KW - Temperature dependence
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579716
DO - https://doi.org/10.1038/s41597-023-02387-6
VL - 10
IS - 1
SP - 1
EP - 9
PB - Springer Nature
AN - OPUS4-57971
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lin, Y.-Y.
A1 - Schleifer, F.
A1 - Holzinger, M.
A1 - Ta, N.
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
A1 - Glatzel, U.
A1 - Fleck, M.
T1 - Quantitative Shape-Classification of Misfitting Precipitates during Cubic to Tetragonal Transformations: Phase-Field Simulations and Experiments
N2 - The effectiveness of the mechanism of precipitation strengthening in metallic alloys depends on the shapes of the precipitates. Two different material systems are considered: tetragonal γ′′ precipitates in Ni-based alloys and tetragonal θ′ precipitates in Al-Cu-alloys. The shape formation and evolution of the tetragonally misfitting precipitates was investigated by means of experiments and phase-field simulations. We employed the method of invariant moments for the consistent shape quantification of precipitates obtained from the simulation as well as those obtained from the experiment. Two well-defined shape-quantities are proposed: (i) a generalized measure for the particles aspect ratio and (ii) the normalized λ2, as a measure for shape deviations from an ideal ellipse of the given aspect ratio. Considering the size dependence of the aspect ratio of γ′′ precipitates, we find good agreement between the simulation results and the experiment. Further, the precipitates’ in-plane shape is defined as the central 2D cut through the 3D particle in a plane normal to the tetragonal c-axes of the precipitate. The experimentally observed in-plane shapes of γ′′-precipitates can be quantitatively reproduced by the phase-field model.
KW - γ″ phase
KW - Phase-field simulation
KW - Misfitting precipitate
KW - Nickel-base alloy
KW - Al-Cu alloy
KW - θ′ phase
KW - Precipitate shape
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522743
DO - https://doi.org/10.3390/ma14061373
VL - 14
IS - 6
SP - 1373
PB - MDPI
AN - OPUS4-52274
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Charmi, Amir
A1 - Falkenberg, Rainer
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Sommer, Konstantin
A1 - Ulbricht, Alexander
A1 - Sprengel, Maximilian
A1 - Saliwan Neumann, Romeo
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Mechanical anisotropy of additively manufactured stainless steel 316L: An experimental and numerical study
N2 - The underlying cause of mechanical anisotropy in additively manufactured (AM) parts is not yet fully understood and has been attributed to several different factors like microstructural defects, residual stresses, melt pool boundaries, crystallographic and morphological textures. To better understand the main contributing factor to the mechanical anisotropy of AM stainless steel 316L, bulk specimens were fabricated via laser powder bed fusion (LPBF). Tensile specimens were machined from these AM bulk materials for three different inclinations: 0◦, 45◦, and 90◦ relative to the build plate. Dynamic Young’s modulus measurements and tensile tests were used to determine the mechanical anisotropy. Some tensile specimens were also subjected to residual stress measurement via neutron diffraction, porosity determination with X-ray micro-computed tomography (μCT), and texture analysis with electron backscatter diffraction (EBSD). These investigations revealed that the specimens exhibited near full density and the detected defects were spherical. Furthermore, the residual stresses in the loading direction were between −74 ± 24 MPa and 137 ± 20 MPa, and the EBSD measurements showed a preferential ⟨110⟩ orientation parallel to the build direction. A crystal plasticity model was used to analyze the elastic anisotropy and the anisotropic yield behavior of the AM specimens, and it was able to capture and predict the experimental behavior accurately. Overall, it was shown that the mechanical anisotropy of the tested specimens was mainly influenced by the crystallographic texture.
KW - Mechanical anisotropy
KW - Residual stress
KW - Crystal plasticity
KW - Selective laser melting (SLM)
KW - Laser beam melting (LBM)
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511719
DO - https://doi.org/10.1016/j.msea.2020.140154
SN - 0921-5093
VL - 799
SP - 140154
PB - Elsevier B.V.
AN - OPUS4-51171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tomiak, F.
A1 - Schartel, Bernhard
A1 - Wolf, M.
A1 - Drummer, D.
T1 - Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)
N2 - Aluminum tris (diethylphosphinate) (AlPi) is known to have an efficient flame-retardant effect when used in poly(butadiene terephthalates) (PBT). Additionally, better flame-retardant effects can be achieved through the partial substitution of AlPi by boehmite in multi-component systems, which have been shown to be an effective synergist due to cooling effects and residue formation. Although the potential of beneficial effects is generally well known, the influence of particle sizes and behavior in synergistic compositions are still unknown. Within this paper, it is shown that the synergistic effects in flammability measured by limiting oxygen index (LOI) can vary depending on the particle size distribution used in PBT. In conducting thermogravimetric analysis (TGA) measurements, it was observed that smaller boehmite particles result in slightly increased char yields, most probably due to increased reactivity of the metal oxides formed, and they react slightly earlier than larger boehmite particles. This leads to an earlier release of water into the system enhancing the hydrolysis of PBT. Supported by Fourier transformation infrared spectroscopy (FTIR), we propose that the later reactions of the larger boehmite particles decrease the portion of highly flammable tetrahydrofuran in the gas phase within early burning stages. Therefore, the LOI index increased by 4 vol.% when lager boehmite particles were used for the synergistic mixture.
KW - Flame retardants
KW - Aluminum diethylphosphinate
KW - Boehmite
KW - Poly(butadiene terephthalates) (PBT)
KW - Mechanical properties
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509286
DO - https://doi.org/10.3390/polym12061315
SN - 2073-4360
VL - 12
IS - 6
SP - 1315
PB - MDPI
AN - OPUS4-50928
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ta, N.
A1 - Bilal, M. U.
A1 - Häusler, I.
A1 - Saxena, A.
A1 - Lin, Y.-Y.
A1 - Schleifer, F.
A1 - Fleck, M.
A1 - Glatzel, U.
A1 - Skrotzki, Birgit
A1 - Darvishi Kamachali, Reza
T1 - Simulation of the θ′ Precipitation Process with Interfacial Anisotropy Effects in Al-Cu Alloys
N2 - The effects of anisotropic interfacial properties and heterogeneous elasticity on the growth and ripening of plate-like θ′-phase (Al2Cu) in Al-1.69 at.% Cu alloy are studied. Multi-phase-field simulations are conducted and discussed in comparison with aging experiments. The precipitate/matrix interface is considered to be anisotropic in terms of its energy and mobility. We find that the additional incorporation of an anisotropic interfacial mobility in conjunction with the elastic anisotropy result in substantially larger aspect ratios of the precipitates closer to the experimental observations. The anisotropy of the interfacial energy shows comparably small effect on the precipitate’s aspect ratio but changes the interface’s shape at the rim. The effect of the chemo-mechanical coupling, i.e., the composition dependence of the elastic constants, is studied as well. We show that the inverse ripening phenomenon, recently evidenced for δ’ precipitates in Al-Li alloys (Park et al. Sci. Rep. 2019, 9, 3981), does not establish for the θ′ precipitates. This is because of the anisotropic stress fields built around the θ′ precipitates, stemming from the precipitate’s shape and the interaction among different variants of the θ′ precipitate, that disturb the chemo-mechanical effects. These results show that the chemo-mechanical effects on the precipitation ripening strongly depend on the degree of sphericity and elastic isotropy of the precipitate and matrix phases.
KW - Aging
KW - Phase-field simulation
KW - Interfacial anisotropy
KW - Chemo-mechanical coupling
KW - Precipitation
KW - Elasticity
KW - θ′-(Al2Cu) precipitate phase
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-522672
DO - https://doi.org/10.3390/ma14051280
VL - 14
IS - 5
SP - 1280
PB - MDPI
AN - OPUS4-52267
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Günther, Martin
A1 - Levchik, S. V.
A1 - Schartel, Bernhard
T1 - Bubbles and collapses: Fire phenomena of flame-retarded flexible polyurethane foams
N2 - Flexible polyurethane foams (FPUF) are easy to ignite and exhibit rapid flame spread. In this paper, the fire phenomena of two standard foam formulations containing tris (1,3-dichloro-2-propyl) phosphate (FR-2) and a halogen-freepoly (ethyl ethylene phosphate) (PNX), respectively, as flame retardants are compared. A multimethodological approach is proposed which combines standard fire tests as well as new investigatory approaches. The thermophysical properties of the foams were determined by thermogravimetric analysis (TG), reaction to small flames was studied by means of the limiting oxygen index (LOI) and UL 94 HBF test, and the burning behavior was investigated with the cone calorimeter. Further, temperature development in burning cone calorimeter samples was monitored using thermocouples, and rheological measurements were performed on pyrolyzed material, delivering insight
into the dripping behavior of the foams. This paper gives comprehensive insight into the fire phenomena of flame-retarded FPUFs that are driven by the two-step decomposition behavior of the foams. LOI and UL 94 HBF tests showed a reduced flammability and reduced tendency to drip for the flame-retarded foams. TG and cone calorimeter measurements revealed that the two-step decomposition behavior causes two stages during combustion, namely structural collapse and pool fire. The flame-retardant mode of action was identified to take place primarily during the foam collapse and be based mainly on flame inhibition. However, some condensed-phase action was been measured, leading to significantly increased melt viscosity and improved dripping behavior for foams containing PNX.
KW - Burning behavior
KW - Flame retardant
KW - Flexible PU foam
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-512145
DO - https://doi.org/10.1002/pat.4939
SN - 1042-7147
SN - 1099-1581
VL - 31
IS - 10
SP - 2185
EP - 2198
PB - Wiley Online Libary
AN - OPUS4-51214
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goedecke, Caroline
A1 - Dittmann, Daniel
A1 - Eisentraut, Paul
A1 - Wiesner, Yosri
A1 - Schartel, Bernhard
A1 - Klack, Patrick
A1 - Braun, Ulrike
T1 - Evaluation of thermoanalytical methods equipped with evolved gas analysis for the detection of microplastic in environmental samples
N2 - Microplastic particles are currently detected in almost all environmental compartments. The results of detection vary widely, as a multitude of very different methods are used with very different requirements for analytical validity.
In this work four thermoanalytical methods are compared and their advantages and limitations are discussed. One of them is thermal extraction-desorption gas chromatography mass spectrometry (TED-GC/MS), an analysis method for microplastic detection that has become established in recent years. In addition, thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS) were applied, two methods that are less common in this field but are still used in other research areas. Finally, microscale combustion calorimeter (MCC) was applied, a method not yet used for microplastic detection.
The presented results are taken from a recently published interlaboratory comparison test by Becker et al. (2020). Here a reference material consisting of suspended matter and specified added polymer masses was examined, and only the results of the recoveries were presented. In the present paper, however, the results for the individual polymers are discussed in detail and individual perspectives for all instruments are shown.
It was found that TED-GC/MS is the most suitable method for samples with unknown matrix and unknown, variable kinds and contents of microplastic. TGA-FTIR is a robust method for samples with known matrix and with defined kinds of microplastic. TGA-MS may offer a solution for the detection of PVC particles in the future. MCC can be used as a very fast and simple screening method for the identification of a potential microplastic load of standard polymers in unknown samples.
KW - Microplastic
KW - TED-GC/MS
KW - TGA-MS
KW - TGA-FTIR
KW - MCC
KW - Thermal analysis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516687
DO - https://doi.org/10.1016/j.jaap.2020.104961
VL - 152
SP - 104961
PB - Elsevier B.V.
AN - OPUS4-51668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tan, Yi
A1 - Wachtendorf, Volker
A1 - Kukofka, Tobias
A1 - Klack, Patrick
A1 - Ruder, J.
A1 - Lin, Xuebao
A1 - Schartel, Bernhard
T1 - Degradation of flame retardance: A comparison of ethylene‐vinyl acetate and low‐density polyethylene cables with two different metal hydroxides
N2 - The durability of flame retardancy is a challenge for cables over long lifetimes. The degradation of flame retardance is investigated in two kinds of exposures, artificial weathering and humidity. In this basic study, typical mineral flame retardants in two polymers frequently used in cable jackets are investigated to get the fundamental picture. Aluminum hydroxide (ATH) and magnesium hydroxide (MDH) are compared in ethylene‐vinyl acetate (EVA), and further in EVA and linear low‐density polyethylene (LLDPE) cables containing the same ATH. The changes in chemical structure at the surface are studied through attenuated total reflectance Fourier transform infrared spectroscopy (ATR‐FTIR), the formation of cracks, and changes in color are investigated. The cone calorimeter and a bench scale fire testing cable module are utilized to evaluate the fire behavior of the cables. Although the flame retardancy deteriorated slightly, it survived harsh exposure conditions for 2000 h. Compared to EVA/MDH and LLDPE/ATH, the fire behavior of EVA/ATH is the least sensitive. Taken together, all of the results converge to estimate that there will be no problem with flame retardancy performance, for materials subjected to natural exposure for several years; the durability of fire retardancy is questionable for longer periods, and thus requires further investigation.
KW - Durability
KW - Flame retardant
KW - Aluminum hydroxide (ATH)
KW - Magnesium hydroxide
KW - Ethylene-vinyl acetate
KW - Cables
KW - Weathering
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519573
DO - https://doi.org/10.1002/app.50149
VL - 138
IS - 14
SP - 50149
PB - Wiley
AN - OPUS4-51957
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Markwart, J. C.
A1 - Battig, Alexander
A1 - Urbaniak, T.
A1 - Haag, K.
A1 - Koschek, K.
A1 - Schartel, Bernhard
A1 - Wurm, F. R.
T1 - Intrinsic flame retardant phosphonate-based vitrimers as a recyclable alternative for commodity polymers in composite materials
N2 - Recycling of crosslinked fiber-reinforced polymers is difficult. Moreover, as they are often based on flammable resins, additional additives are needed. So-called “vitrimers” open the possibility of Recycling and reprocessing and repairing with dynamically crosslinked chemistries. To date, vitrimer-based composites still need flame retardant additives, such as organophosphates. An additive-free vitrimer composite has not been reported. Herein, we synthesized an intrinsic flame-retardant vitrimer, relying on vinylogous polyurethanes containing covalently installed phosphonates as flame-retardant units and prepared glassfiber-reinforced composites. We studied recycling and flame retardant properties and compared the data to phosphorus-free vitrimers and conventional epoxy resins (with and without additive flame retardant).
Our phosphonate-based vitrimer proved in first tests, a flame retardant effect comparable to commercial flame retardant resins. The bending strength and bending modulus for the phosphorus-vitrimer glass fiber composites were comparable to glass fiber composites with permanently cross-linked epoxies. In summary, we were able to prove that the covalent installation of phosphonates into vitrimers allows the preparation of recyclable and intrinsic flame retardant composites that do not need flame retardant additives. We believe this concept can be expanded to other polymer networks and additives to generate recyclable and sustainable high-performance materials.
KW - Vitrimer
KW - Flame retardant
KW - Recyclable
KW - Organophosphonate
KW - Polyurethane
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-510889
DO - https://doi.org/10.1039/d0py00275e
VL - 11
IS - 30
SP - 4933
EP - 4941
AN - OPUS4-51088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rockenhäuser, Christian
A1 - Rowolt, C.
A1 - Milkereit, B.
A1 - Darvishi Kamachali, Reza
A1 - Kessler, O.
A1 - Skrotzki, Birgit
T1 - On the long-term aging of S-phase in aluminum alloy 2618A
N2 - The aluminum alloy 2618A is applied for engine components such as radial compressor wheels which operate for long time at elevated temperatures. This results in coarsening of the hardening precipitates and degradation in mechanical properties during the long-term operation, which is not taken into account in the current lifetime prediction models due to the lack of quantitative microstructural and mechanical data. To address this issue, a quantitative investigation on the evolution of precipitates during long-term aging at 190 °C for up to 25,000 h was conducted. Detailed transmission electron microscopy (TEM) was combined with Brinell hardness measurements and thorough differential scanning calorimetry (DSC) experiments. The results showthat GPB zones and S-phase Al2CuMg grow up to < 1,000 h during which the GPB zones dissolve and S-phase precipitates form. For longer aging times, only S-phase precipitates coarsen, which can be well described using the Lifshitz–Slyozov Wagner theory of ripening. A thorough understanding of the underlying microstructural processes is a prerequisite to enable the integration of aging behavior into the established lifetime models for components manufactured from alloy 2618A.
KW - Long-term aging
KW - Transmission electron microscopy (TEM)
KW - Differential scanning calorimetry (DSC)
KW - Microstructure
KW - S-phase
KW - Ostwald ripening
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-519899
DO - https://doi.org/10.1007/s10853-020-05740-x
SN - 0022-2461
VL - 56
IS - 14
SP - 8704
EP - 8716
PB - Springer Nature
AN - OPUS4-51989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Velencoso, M. M.
A1 - Battig, Alexander
A1 - Markwart, J. C.
A1 - Schartel, Bernhard
A1 - Wurm, F. R.
T1 - Molecular firefighting – How modern phosphorus chemistry can help solve the challenge of flame retardancy
N2 - The ubiquity of polymeric materials in daily life Comes with an increased fire risk, and sustained research into efficient flame retardants is key to ensuring the safety of the populace and material goods from accidental fires. Phosphorus, a versatile and effective element for use in flame retardants, has the potential to supersede the halogenated variants that are still widely used today: current formulations employ a variety of modes of action and methods of implementation, as additives or as reactants, to solve the task of developing flameretarding polymeric materials. Phosphorus-based flame retardants can act in both the gas and condensed phase during a fire. This Review investigates how current phosphorus chemistry helps in reducing the flammability of polymers, and addresses the future of sustainable, efficient, and safe phosphorus-based flame-retardants from renewable sources.
KW - Flame retardant
KW - Phosphorus
KW - Halogen-free
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457009
DO - https://doi.org/10.1002/anie.201711735
SN - 1433-7851
SN - 1521-3773
VL - 57
IS - 33
SP - 10450
EP - 10467
PB - Wiley VHC
AN - OPUS4-45700
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Skrotzki, Birgit
A1 - Stegemann, Robert
A1 - Löwe, Peter
A1 - Kreutzbruck, M.
T1 - The role of surface topography on deformation-induced magnetization under inhomogeneous elastic-plastic deformation
N2 - It is widely accepted that the magnetic state of a ferromagnetic material may be irreversibly altered by mechanical loading due to magnetoelastic effects. A novel standardized nondestructive testing (NDT) technique uses weak magnetic stray fields, which are assumed to arise from inhomogeneous deformation, for structural health monitoring (i.e., for detection and assessment of damage). However, the mechanical and microstructural complexity of damage has hitherto only been insufficiently considered. The aim of this study is to discuss the phenomenon of inhomogeneous “self-magnetization” of a polycrystalline ferromagnetic material under inhomogeneous deformation experimentally and with stronger material-mechanical focus. To this end, notched specimens were elastically and plastically deformed. Surface magnetic states were measured by a three-axis giant magnetoresistant (GMR) sensor and were compared with strain field (digital image correlation) and optical topography measurements. It is demonstrated that the stray fields do not solely form due to magnetoelastic effects. Instead, inhomogeneous plastic deformation causes topography, which is one of the main origins for the magnetic stray field formation. Additionally, if not considered, topography may falsify the magnetic signals due to variable lift-off values. The correlation of magnetic vector components with mechanical tensors, particularly for multiaxial stress/strain states and inhomogeneous elastic-plastic deformations remains an issue.
KW - Magnetic stray fields
KW - Magnetomechanical effect
KW - Damage
KW - Topography
KW - Multiaxial deformation
KW - Notch
KW - Plastic deformation
KW - Metal magnetic memory
KW - Digital image correlation
KW - Structural steel
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457878
DO - https://doi.org/10.3390/ma11091518
SN - 1996-1944
VL - 11
IS - 9
SP - 1518, 1
EP - 26
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-45787
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Häusler, Ines
A1 - Darvishi Kamachali, Reza
A1 - Hetaba, W.
A1 - Skrotzki, Birgit
T1 - Thickening of T-1 Precipitates during Aging of a High Purity Al–4Cu–1Li–0.25Mn Alloy
N2 - The age hardening response of a high-purity Al–4Cu–1Li–0.25Mn alloy (wt. %) during isothermal aging without and with an applied external load was investigated. Plate shaped nanometer size T1 (Al2CuLi) and θ′ (Al2Cu) hardening phases were formed. The precipitates were analyzed with respect to the development of their structure, size, number density, volume fraction and associated transformation strains by conducting transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM) studies in combination with geometrical Phase analysis (GPA). Special attention was paid to the thickening of T1 phase. Two elementary types of single-layer T1 precipitate, one with a Li-rich (Type 1) and another with an Al-rich (Defect Type 1) central layer, were identified. The results show that the Defect Type 1 structure can act as a precursor for the Type 1 structure. The thickening of T1 precipitates occurs by alternative stacking of These two elementary structures. The thickening mechanism was analyzed based on the magnitude of strain associated with the precipitation transformation normal to its habit plane. Long-term aging and aging under load resulted in thicker and structurally defected T1 precipitates. Several types of defected precipitates were characterized and discussed. For θ′ precipitates, a ledge mechanism of
thickening was observed. Compared to the normal aging, an external load applied to the peak aged state leads to small variations in the average sizes and volume fractions of the precipitates.
KW - Al-Cu-Li-alloy
KW - Precipitation
KW - T1 precipitate
KW - Microstructure evolution
KW - Thickening
KW - Creep
KW - Volume fraction
KW - Number density
KW - Strain difference
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-471207
DO - https://doi.org/10.3390/ma12010030
SN - 1996-1944
VL - 12
IS - 1
SP - 30, 1
EP - 23
PB - MDPI
AN - OPUS4-47120
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Günther, Martin
A1 - Lorenzetti, A.
A1 - Schartel, Bernhard
T1 - Fire Phenomena of Rigid Polyurethane Foams
N2 - Rigid polyurethane foams (RPUFs) typically exhibit low thermal inertia, resulting in short ignition times and rapid flame spread. In this study, the fire phenomena of RPUFs were investigated using a multi-methodological approach to gain detailed insight into the fire behaviour of pentaneand water-blown polyurethane (PUR) as well as pentane-blown polyisocyanurate Polyurethane (PIR) foams with densities ranging from 30 to 100 kg/m3. Thermophysical properties were studied using thermogravimetry (TG); flammability and fire behaviour were investigated by means of the limiting oxygen index (LOI) and a cone calorimeter. Temperature development in burning cone calorimeter specimens was monitored with thermocouples inside the foam samples and visual investigation of quenched specimens’ cross sections gave insight into the morphological changes during burning. A comprehensive investigation is presented, illuminating the processes taking place during foam combustion. Cone calorimeter tests revealed that in-depth absorption of radiation is a significant factor in estimating the time to ignition. Cross sections examined with an electron scanning microscope (SEM) revealed a pyrolysis front with an intact foam structure underneath, and temperature measurement inside burning specimens indicated that, as foam density increased, their burning behaviour shifted towards that of solid materials. The superior fire performance of PIR foams was found to be based on the cellular structure, which is retained in the residue to some extent.
KW - Foam
KW - Polyurethane
KW - Fire behaviour
KW - Flammability
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-465577
DO - https://doi.org/10.3390/polym10101166
SN - 2073-4360
VL - 10
IS - 10
SP - 1166-1
EP - 1166-22
PB - MDPI
AN - OPUS4-46557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sut, Aleksandra
A1 - Metzsch-Zilligen, E.
A1 - Großhauser, M.
A1 - Pfaendner, R.
A1 - Schartel, Bernhard
T1 - Rapid mass calorimeter as a high-throughput screening method for the development of flame-retarded TPU
N2 - The rapid mass calorimeter (RMC) was used as a screening tool based on accelerated fire testing to assess flame-retarded thermoplastic polyurethane (TPU). The reliability of RMC results was proven with the cone calorimeter as reference fire test. The influence of melamine cyanurate (MC) concentration on the fire performance of TPU was investigated, along with some flame-retardant combinations such as MC with aluminium diethylphosphinate (AlPi), aluminium trihydrate (ATH), and melamine polyphosphate (MPP). The two-stage burning behaviour of TPU was investigated in detail; the first stage corresponds mainly to the hard segments' decomposition and has a much lower effective heat of combustion (EHC) than the second stage, in which mainly the soft segments decompose and an intensive liquid pool fire is observed in the cone calorimeter set-up. In addition to fire testing with the cone calorimeter, RMC, and UL 94 flammability tests, the decomposition of the materials was investigated using thermogravimetric analysis coupled with infrared spectrometry (TGeFTIR). TPU/MC/AlPi shows the most promising results, achieving V-0 classification in UL 94 and reducing the extreme peak heat release rate (PHRR) of the liquid pool fire from 3154 kW/m2 to 635 kW/m2. Using MC/AlPi/MPP enhances the latter PHRR reduction further. The decomposition products identified in the gas phase via TGeFTIR reveal specific MCeAlPi eMPP interactions, as they differ from products seen in systems with MC/AlPi or MC/MPP. Correlations between RMC and cone calorimeter results were examined and presented in the final part of the paper. Several characteristics correlate strongly, pointing out that RMC is a reliable high-throughput fire testing method to screen multicomponent flame-retardant solutions in TPU.
KW - Thermoplastic polyurethane
KW - Flame retardancy
KW - Rapid mass calorimeter
KW - High throughput screening
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-456982
SN - 0141-3910
SN - 1873-2321
VL - 156
SP - 43
EP - 58
PB - Elsevier Ltd.
AN - OPUS4-45698
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, Sebastian
A1 - Sánchez-Olivares, G.
A1 - Pérez-Chávez, R.
A1 - Schartel, Bernhard
T1 - Natural keratin and coconut fibres from industrial wastes in flame retarded thermoplastic starch biocomposites
N2 - Natural keratin fibres derived from Mexican tannery waste and coconut fibres from coconut processing waste were used as fillers in commercially available, biodegradable thermoplastic starch-polyester blend to obtain sustainable biocomposites. The morphology, rheological and mechanical properties as well as pyrolysis, flammability and forced flaming combustion behaviour of those biocomposites were investigated. In order to open up new application areas for these kinds of biocomposites, ammonium polyphosphate (APP) was added as a flame retardant. Extensive flammability and cone calorimeter studies revealed a good flame retardance effect with natural fibres alone and improved effectiveness with the addition of APP. In fact, it was shown that replacing 20 of 30 wt. % of APP with keratin fibres achieved the same effectiveness. In the case of coconut fibres, a synergistic effect led to an even lower heat release rate
and total heat evolved due to reinforced char residue. This was confirmed via scanning electron microscopy of the char structure. All in all, these results constitute a good approach towards sustainable and biodegradable fibre reinforced biocomposites with improved flame retardant properties.
KW - Biomaterials
KW - Biodegradable
KW - Calorimetry
KW - Composites
KW - Flame retardance
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472518
DO - https://doi.org/10.3390/ma12030344
SN - 1996-1944
VL - 12
IS - 3
SP - 344, 1
EP - 24
PB - MDPI
AN - OPUS4-47251
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sut, Aleksandra
A1 - Metzsch-Zilligen, E.
A1 - Großhauser, M.
A1 - Pfaendner, R.
A1 - Schartel, Bernhard
T1 - Synergy between melamine cyanurate, melamine polyphosphate and aluminum diethylphosphinate in flame retarded thermoplastic polyurethane
N2 - The multicomponent flame retardant system of melamine polyphosphate (MPP), melamine cyanurate (MC) and aluminum diethylphosphinate (AlPi) is proposed and investigated for thermoplastic polyurethane (TPU). The synergy between those additives and the resulting superior fire performance are discussed. Systematically varied sets of flame retarded TPU with various MPP/MC/AlPi ratios were investigated in terms of fire behavior, pyrolysis products and mechanical properties. The total amount of the additives was always 30 wt.-%. Further, the influence of various AlPi concentrations was investigated. The optimal MPP:MC ratio was determined while keeping the amount of AlPi constant. The combination of 8 wt.-% MPP, 12 wt.-% MC and 10 wt.-% is proposed as the most promising halogen free flame retardant formulation for TPU, because it yielded a reduction in PHRR from 2660 kW/m2 (TPU) to 452 kW/m2 and enabled V-0 classification in the UL 94 test. Combinations of MPP and MC as well a high concentration of AlPi are beneficial for the mechanical properties e.g. tensile strength and elongation at break of the formulations and could be a strong competitor to commercial flame retarded TPUs.
KW - Thermoplastic polyurethane
KW - Synergy
KW - Melamine cyanurate
KW - Melamine polyphosphate
KW - Aluminum diethylphosphinate
KW - Rapid mass calorimeter
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472523
DO - https://doi.org/10.1016/j.polymertesting.2019.01.001
SN - 0142-9418
VL - 74
SP - 196
EP - 204
PB - Elsevier Ltd.
AN - OPUS4-47252
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Schork, B.
A1 - Bernhard, J.
A1 - Kaffenberger, M.
T1 - Multiple crack initiation and propagation in weldments under fatigue loading
N2 - The work aims at addressing the modelling and implementation of criteria for multiple crack propagation, including interaction and coalescence, for a more reliable fracture mechanics-based prediction of stress-life curves for weldments.
A large experimental work is presented in which micro-cracks have been made visible by heat-tinting at successive stages of fatigue life of the welded specimens. Here the correlation between the number of initiation sites and the applied stress level has been also investigated.
The criteria have been implemented in in-house software, which allows multiple fatigue crack propagation, and validated against selected experimental tests. The results have shown that the modelling of multiple crack propagation and interaction is crucial for the prediction of the fatigue strength of weldments, both in finite and infinite life regime.
T2 - FDMD 2017
CY - Lecco, Italy
DA - 19.09.2017
KW - Weldments
KW - Fatigue strength
KW - Multiple crack propagation
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438593
DO - https://doi.org/10.1016/j.prostr.2017.11.108
SN - 2452-3216
VL - 7
SP - 423
EP - 430
PB - Elsevier B.V.
AN - OPUS4-43859
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Daus, Lars-Hendrik
A1 - Korzen, Manfred
A1 - Schartel, Bernhard
T1 - High-throughput fire tests and weathering-induced degradation behaviour of intumescent coatings
N2 - In this work, the weathering-induced degradation of intumescent coatings was investigated by a systematic and comprehensive approach. A mechanism is revealed that is proposed to be responsible for the loss of function of intumescent coatings induced by weathering.
First, the thermal decomposition of artificially weathered intumescent coatings was examined. To get a better understanding of the weathering and ageing phenomena, the degradation behaviour of the single ingredients during the weathering process was investigated, as well as their chemical and physical interactions. For the systematic approach, the materials that are essential for intumescence (ammonium polyphosphate, pentaerythritol, titanium dioxide, melamine and the binder) are treated with moisture, elevated temperature and UV radiation.
Thermogravimetry (TG) and IR spectroscopy were used to compare the initial samples with their different grades of weathering. We demonstrate that ammonium polyphosphate, melamine and the binder are mainly responsible for the ageing process. Further, it was demonstrated that TG and IR spectroscopy are suitable measuring methods to detect the effects of weathering on intumescent coatings.
Finally, a small-scale fire test procedure is introduced. Based on the reduction of the sample size, up to 50 samples can be tested in a single fire test. The results of this fire test have the same quality as the results from standard intermediate fire tests corresponding to DIN 4102-8.
T2 - 3rd European Symposium on Fire Safety Science
CY - Nancy, France
DA - 12.09.1018
KW - Weathering
KW - Intumescent coatings
KW - High-Throughput Fire Tests
PY - 2018
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-472023
UR - http://iopscience.iop.org/article/10.1088/1742-6596/1107/3/032014/pdf
DO - https://doi.org/10.1088/1742-6596/1107/3/032014
VL - 1107
SP - 032014
PB - IOP Publishing
CY - Bristol
AN - OPUS4-47202
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bayerlein, Bernd
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
A1 - Birkholz, Henk
A1 - Portella, Pedro Dolabella
A1 - Skrotzki, Birgit
T1 - FAIR and Structured Data: A Domain Ontology Aligned with Standard‐Compliant Tensile Testing
N2 - The digitalization of materials science and engineering (MSE) is currently leading to remarkable advancements in materials research, design, and optimization, fueled by computer‐driven simulations, artificial intelligence, and machine learning. While these developments promise to accelerate materials innovation, challenges in quality assurance, data interoperability, and data management have to be addressed. In response, the adoption of semantic web technologies has emerged as a powerful solution in MSE. Ontologies provide structured and machine‐actionable knowledge representations that enable data integration, harmonization, and improved research collaboration. This study focuses on the tensile test ontology (TTO), which semantically represents the mechanical tensile test method and is developed within the project Plattform MaterialDigital (PMD) in connection with the PMD Core Ontology. Based on ISO 6892‐1, the test standard‐compliant TTO offers a structured vocabulary for tensile test data, ensuring data interoperability, transparency, and reproducibility. By categorizing measurement data and metadata, it facilitates comprehensive data analysis, interpretation, and systematic search in databases. The path from developing an ontology in accordance with an associated test standard, converting selected tensile test data into the interoperable resource description framework format, up to connecting the ontology and data is presented. Such a semantic connection using a data mapping procedure leads to an enhanced ability of querying. The TTO provides a valuable resource for materials researchers and engineers, promoting data and metadata standardization and sharing. Its usage ensures the generation of finable, accessible, interoperable, and reusable data while maintaining both human and machine actionability.
KW - Data Interoperability
KW - Domain Ontology Development
KW - FAIR Data Management
KW - Knowledge Representation
KW - Tensile Test Ontology
KW - Semantic Web Technologies
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598142
DO - https://doi.org/10.1002/adem.202400138
SN - 1438-1656
SP - 1
EP - 19
PB - Wiley VHC-Verlag
AN - OPUS4-59814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fareed, Adnan
A1 - Rosalie, Julian
A1 - Kar, Satyakam
A1 - Fähler, Sebastian
A1 - Maaß, Robert
T1 - Small-scale functional fatigue of a Ni-Mn-Ga Heusler alloy
N2 - Functional fatigue of shape-memory alloys is a considerable threat to the reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipation amounts to about 1/5 of the bulk counterpart and remains unaffected during cycling, even after the introduction of dislocation structures via plastic straining. Plastic yielding and the transformation stress largely exceed the known bulk values. However, the transformation-stress is found to depend on plastic pre-straining, which suggests that the size-affected transformation stress is sensitive to the initial defect structure and that it can be tuned by a targeted introduction of dislocations. These findings demonstrate the high suitability of Ni-Mn-Ga as a robust shape-memory alloy in small-scale functional device engineering.
KW - Superelasticity
KW - Shape-memory alloys
KW - Functional fatigue
KW - Ni-Mn-Ga
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600695
DO - https://doi.org/10.1016/j.actamat.2024.119988
VL - 274
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-60069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Beygi Nasrabadi, Hossein
A1 - Hanke, T.
A1 - Weber, M.
A1 - Eisenbart, M.
A1 - Bauer, F.
A1 - Meissner, R.
A1 - Dziwis, G.
A1 - Tikana, L.
A1 - Chen, Yue
A1 - Skrotzki, Birgit
T1 - Toward a digital materials mechanical testing lab
N2 - To accelerate the growth of Industry 4.0 technologies, the digitalization of mechanical testing laboratories as one of the main data-driven units of materials processing industries is introduced in this paper. The digital lab infrastructure consists of highly detailed and standard-compliant materials testing knowledge graphs for a wide range of mechanical testing processes, as well as some tools that enable the efficient ontology development and conversion of heterogeneous materials’ mechanical testing data to the machine-readable data of uniform and standardized structures. As a basis for designing such a digital lab, the mechanical testing ontology (MTO) was developed based on the ISO 23718 and ISO/IEC 21838-2 standards for the semantic representation of the mechanical testing experiments, quantities, artifacts, and report data. The trial digitalization of materials mechanical testing lab was successfully performed by utilizing the developed tools and knowledge graph of processes for converting the various experimental test data of heterogeneous structures, languages, and formats to standardized Resource Description Framework (RDF) data formats. The concepts of data storage and data sharing in data spaces were also introduced and SPARQL queries were utilized to evaluate how the introduced approach can result in the data retrieval and response to the competency questions. The proposed digital materials mechanical testing lab approach allows the industries to access lots of trustworthy and traceable mechanical testing data of other academic and industrial organizations, and subsequently organize various data-driven research for their faster and cheaper product development leading to a higher performance of products in engineering and ecological aspects.
KW - General Engineering
KW - General Computer Science
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-582698
DO - https://doi.org/10.1016/j.compind.2023.104016
SN - 0166-3615
VL - 153
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-58269
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zia, Ghezal Ahmad Jan
A1 - Hanke, Thomas
A1 - Skrotzki, Birgit
A1 - Völker, Christoph
A1 - Bayerlein, Bernd
T1 - Enhancing Reproducibility in Precipitate Analysis: A FAIR Approach with Automated Dark-Field Transmission Electron Microscope Image Processing
N2 - AbstractHigh-strength aluminum alloys used in aerospace and automotive applications obtain their strength through precipitation hardening. Achieving the desired mechanical properties requires precise control over the nanometer-sized precipitates. However, the microstructure of these alloys changes over time due to aging, leading to a deterioration in strength. Typically, the size, number, and distribution of precipitates for a quantitative assessment of microstructural changes are determined by manual analysis, which is subjective and time-consuming. In our work, we introduce a progressive and automatable approach that enables a more efficient, objective, and reproducible analysis of precipitates. The method involves several sequential steps using an image repository containing dark-field transmission electron microscopy (DF-TEM) images depicting various aging states of an aluminum alloy. During the process, precipitation contours are generated and quantitatively evaluated, and the results are comprehensibly transferred into semantic data structures. The use and deployment of Jupyter Notebooks, along with the beneficial implementation of Semantic Web technologies, significantly enhances the reproducibility and comparability of the findings. This work serves as an exemplar of FAIR image and research data management.
KW - Industrial and Manufacturing Engineering
KW - General Materials Science
KW - Automated image analysis
KW - FAIR research data management
KW - Reproducibility
KW - microstructural changes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593905
DO - https://doi.org/10.1007/s40192-023-00331-5
SN - 2193-9772
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
CY - Heidelberg
AN - OPUS4-59390
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Piesker, Benjamin
A1 - Ávila Calderón, Luis
A1 - Mohr, Gunther
A1 - Rehmer, Birgit
A1 - Agudo Jácome, Leonardo
A1 - Hilgenberg, Kai
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature
N2 - This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters.
KW - Additive manufacturing
KW - Fatigue damage
KW - Heat treatment
KW - Inconel 718
KW - Laser powder bed fusion
KW - Low-cycle fatigue
KW - Tensile strength
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599316
DO - https://doi.org/10.1002/adem.202302122
SN - 1527-2648
SP - 1
EP - 17
PB - Wiley
AN - OPUS4-59931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos, José Antonio
A1 - Balderas‐Xicohténcatl, Rafael
A1 - Al Shakhs, Ali N.
A1 - Berenguer‐Murcia, Ángel
A1 - Buckley, Craig E.
A1 - Cazorla‐Amorós, Diego
A1 - Charalambopoulou, Georgia
A1 - Couturas, Fabrice
A1 - Cuevas, Fermin
A1 - Fairen‐Jimenez, David
A1 - Heinselman, Karen N.
A1 - Humphries, Terry D.
A1 - Kaskel, Stefan
A1 - Kim, Hyunlim
A1 - Marco‐Lozar, Juan P.
A1 - Oh, Hyunchul
A1 - Parilla, Philip A.
A1 - Paskevicius, Mark
A1 - Senkovska, Irena
A1 - Shulda, Sarah
A1 - Silvestre‐Albero, Joaquin
A1 - Steriotis, Theodore
A1 - Tampaxis, Christos
A1 - Hirscher, Michael
A1 - Maiwald, Michael
T1 - Establishing ZIF‐8 as a reference material for hydrogen cryoadsorption: An interlaboratory study
N2 - Hydrogen storage by cryoadsorption on porous materials has the advantages of low material cost, safety, fast kinetics, and high cyclic stability. The further development of this technology requires reliable data on the H2 uptake of the adsorbents, however, even for activated carbons the values between different laboratories show sometimes large discrepancies. So far no reference material for hydrogen cryoadsorption is available. The metal‐organic framework ZIF‐8 is an ideal material possessing high thermal, chemical, and mechanical stability that reduces degradation during handling and activation. Here, we distributed ZIF‐8 pellets synthesized by extrusion to 9 laboratories equipped with 15 different experimental setups including gravimetric and volumetric analyzers. The gravimetric H2 uptake of the pellets was measured at 77 K and up to 100 bar showing a high reproducibility between the different laboratories, with a small relative standard deviation of 3–4 % between pressures of 10–100 bar. The effect of operating variables like the amount of sample or analysis temperature was evaluated, remarking the calibration of devices and other correction procedures as the most significant deviation sources. Overall, the reproducible hydrogen cryoadsorption measurements indicate the robustness of the ZIF‐8 pellets, which we want to propose as a reference material.
KW - Physical and theoretical chemistry
KW - Atomic and molecular physics, and optics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594788
DO - https://doi.org/10.1002/cphc.202300794
SN - 1439-7641
SP - 1
EP - 7
PB - Wiley
CY - Weinheim
AN - OPUS4-59478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Chaudry, Mohsin Ali
A1 - Scheuschner, Nils
A1 - Blasón Gonzalez, Sergio
A1 - Madia, Mauro
A1 - Hilgenberg, Kai
T1 - Thermal history transfer from complex components to representative test specimens in laser powder bed fusion
N2 - Additively manufactured components are characterized by heterogeneous mechanical properties due to variations of the microstructure, flaws and residual stresses resulting from the inhomogeneous fabrication process. The large number of influencing factors poses a further challenge in understanding the correlation between material properties, process parameters and component geometry. Therefore, the qualification of components based on witness specimens produced within the same job is questionable. This work aims to present a new strategy for the characterization of PBF-LB/M components based on representative specimens. The key assumption is the feasibility of a transfer of the thermal history from a component to a specimen. It is assumed that similar material properties are determined for components and specimens produced adopting a similar thermal history. After the definition of a region of interest in the component, a combination of thermal analyses by means of finite elements and in-situ experimental determination of the thermal history through infrared thermography is used to produce test coupons with a similar thermal history. The effectiveness of the procedure is demonstrated on a pressure vessel for applications in the chemical industry.
KW - Additive manufacturing
KW - Heat accumulation
KW - Thermal history
KW - In situ monitoring
KW - Process simulation
KW - Representative specimens
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-602651
DO - https://doi.org/10.1007/s40964-024-00689-8
SN - 2363-9512
SN - 2363-9520
SP - 1
EP - 16
PB - Springer
CY - Cham, Switzerland
AN - OPUS4-60265
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tabaka, Weronika
A1 - Meinel, Dietmar
A1 - Schartel, Bernhard
T1 - Sacrifice Few to Save Many: Fire Protective Interlayers in Carbon- Fiber-Reinforced Laminates
N2 - The fire protection of carbon-fiber-reinforced polymer (CFRP) laminates often relies on flame-retardant coatings, but in some applications, their efficacy may diminish upon direct fire exposure due to rapid pyrolysis. This study introduces an innovative approach by integrating protective interlayers within the laminate structure to enhance the fire resistance. Various materials, including ceramic composite WHIPOX, titanium foil, poly(etherimide) (PEI) foil, basalt fibers, rubber mat, and hemp fibers, were selected as protective interlayers. These interlayers were strategically placed within the laminate layout to form a sacrificial barrier, safeguarding the integrity of the composite. Bench-scale fire resistance tests were conducted, where fire (180 kW/m2) was applied directly to the one side of the specimen by a burner while a compressive load was applied at the same time. Results indicate significant prolongation of time to failure for CFRP laminates with protective interlayers, which is up to 10 times longer. This innovative approach represents a potential advance in fire protection strategies for CFRP laminates, offering improved resilience against fire-induced structural failure.
KW - Composites in fire
KW - Fire resistance
KW - Fire retardant interlayers
KW - Laminate design
KW - Carbon fibre reinforced
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601943
DO - https://doi.org/10.1021/acsomega.4c01408
SN - 2470-1343
VL - 9
IS - 22
SP - 23703
EP - 23712
PB - ACS
AN - OPUS4-60194
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fornacon-Wood, C.
A1 - Stühler, M. R.
A1 - Gallizioli, C.
A1 - Manjunatha, B. R.
A1 - Wachtendorf, Volker
A1 - Schartel, Bernhard
A1 - Plajer, A. J.
T1 - Precise construction of weather-sensitive poly(ester-alt-thioesters) from phthalic thioanhydride and oxetane
N2 - We report the selective ring opening copolymerisation (ROCOP) of
oxetane and phthalic thioanhydride by a heterobimetallic Cr(III)K
catalyst precisely yielding semi-crystalline alternating poly(esteralt-
thioesters) which show improved degradability due to the
thioester links in the polymer backbone.
KW - Sulfur containing polymers
KW - Durability
KW - Weathering
KW - Synthesis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-590762
DO - https://doi.org/10.1039/d3cc03315e
SN - 1364-548X
VL - 59
IS - 76
SP - 11353
EP - 11356
PB - RSC
AN - OPUS4-59076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Treitli, Sebastian C.
A1 - Mies, Undine S.
A1 - Radek, Renate
A1 - Zinnhardt, Patricia A.
A1 - Silva, Joana Maria Kästle
A1 - Reuter, Lisa
A1 - Röhr, Natalie A.
A1 - Platt, Katja
A1 - Hervé, Vincent
A1 - Plarre, Rüdiger
A1 - Marini, Mario
A1 - Brune, Andreas
T1 - Metabolic capacities of large "pillotinaceous" spirochetes from termite guts and their placement among Breznakiellaceae
N2 - Background
Spirochetes are the most abundant bacterial group in the hindgut of termites. The largest species, with cell lengths of up to 100 µm, have been provisionally classified in the family “Pillotinaceae” based exclusively on morphological traits. However, in the absence of cultured representatives, their phylogenetic position and metabolism remain entirely unknown.
Results
We investigated phylogeny and metabolic capacities of “pillotinaceous” spirochetes using single-cell techniques, electron microscopy, and fluorescence in situ hybridization. All sequences of large spirochetes obtained from various termites fell into four distinct, well-supported clusters within the family Breznakiellaceae. Based on ultrastructural features, three of the clusters were assigned to the genera Pillotina, Hollandina, and the newly established genus Hollandinoides; a fourth cluster was tentatively assigned to the genus Clevelandina. Functional analysis of the single-cell genomes of Pillotina corrugata sp. nov., Hollandina grandis sp. nov., and Hollandinoides gharagozlouae gen. nov. sp. nov., combined with comparative genomics of other uncultured relatives, demonstrated differences in the capacity to degrade cellulose, hemicelluloses, and dextrins. While members of the genus Pillotina have a fermentative metabolism, members of the other genera encode a Wood–Ljungdahl pathway and, in the case of Hollandina, a group-III nitrogenase, suggesting roles in reductive acetogenesis and nitrogen fixation.
Conclusions
Our results provide the first molecular data on pillotinaceous spirochetes. We show that the three genera covered in our study belong to the family Breznakiellaceae, which harbors the majority of termite-gut spirochetes. Comparative genome analysis indicated that the large spirochetes in termite guts have distinct roles in symbiotic digestion.
KW - Spirochetes
KW - Phylogenomics
KW - Gut microbiota
KW - Single-cell techniques
KW - Ultrastructure
KW - Pillotinaceae
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-658577
DO - https://doi.org/10.1186/s12915-026-02591-x
SN - 1741-7007
VL - 24
SP - 1
EP - 21
PB - Springer
CY - Berlin
AN - OPUS4-65857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tóth, Péter
A1 - Hofmann-Böllinghaus, Anja
A1 - Dumont, Fabien
A1 - Anderson, Johan
A1 - Sjöström, Johan
A1 - Bergius, Mikael
A1 - Chiva, Roman
A1 - Lalu, Octavian
T1 - Finalisation of the European Approach to Assess the Fire Performance of Facades—Brief Information on the Outcome of the Project
N2 - This research was conducted within the framework of project SI2.825082, funded by the European Commission—DG GROW. The project's objective was to finalise a European approach for assessing the fire performance of façades under medium and large fire exposure conditions. The national standards BS 8414‐1:2020/BS 8414‐2:2020 and DIN 4102‐20:2017 served as the foundation for developing the new assessment method. As part of the project, a theoretical round robin, initial testing activities and a large‐scale experimental round robin were carried out. The theoretical round robin aimed to examine how different laboratories interpreted the preliminary assessment method. Subsequently, the initial testing phase explored the design of the fire source, combustion chamber and secondary opening. The experimental round robin involved testing four façade systems across three laboratories using the assessment method documents, resulting in 12 tests for medium‐scale and 12 for large‐scale exposure—24 tests in total. These tests provided data to develop a calibration scheme and define appropriate performance criteria for classification. In this paper, the representatives of the project consortium summarise the research process and outline the proposed testing and evaluation methodology, which is intended to form the foundation of a future European testing standard for façades. The article also highlights the need for further research to establish rules for extended application of test results.
KW - Facade
KW - Testing
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654731
DO - https://doi.org/10.1002/fam.70042
SN - 0308-0501
SP - 1
EP - 27
PB - John Wiley & Sons Ltd.
AN - OPUS4-65473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Drexler, A
A1 - Konert, Florian
A1 - Sobol, Oded
A1 - Rhode, Michael
A1 - Domitner, J
A1 - Sommitsch, C
A1 - Böllinghaus, Thomas
T1 - Enhanced gaseous hydrogen solubility in ferritic and martensitic steels at low temperatures
N2 - Metals that are exposed to high pressure hydrogen gas may undergo detrimental failure by embrittlement. Understanding the mechanisms and driving forces of hydrogen absorption on the surface of metals is crucial for avoiding hydrogen embrittlement. In this study, the effect of stress-enhanced gaseous hydrogen uptake in bulk metals is investigated in detail. For that purpose, a generalized form of Sievert's law is derived from thermodynamic potentials considering the effect of microstructural trapping sites and multiaxial stresses. This new equation is parametrized and verified using experimental data for carbon steels, which were charged under gaseous hydrogen atmosphere at pressures up to 1000 bar. The role of microstructural trapping sites on the parameter identification is critically discussed.
KW - Hydrogen
KW - Thermodynamic modelling
KW - Pressure-dependent solubility
KW - Steel
KW - Trapping
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-559307
DO - https://doi.org/10.1016/j.ijhydene.2022.09.109
SN - 0360-3199
VL - 47
IS - 93
SP - 39639
EP - 39653
PB - Elsevier Ltd.
AN - OPUS4-55930
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hahn, Sarah‐K.
A1 - Gnutzmann, Tanja
A1 - Meinert, Marion
A1 - Hofmann-Böllinghaus, Anja
A1 - Oberhagemann, Dirk
A1 - Krause, Ulrich
T1 - Incipient Fires—Definition, Detection and Extinguishment by Laypersons
N2 - The earlier a fire is noticed, the less developed it is and the easier it can be prevented respectively stopped, even by laypersons. Within the research project ‘TEBRAS’ the incipient phase of fires was investigated in detail. In the course of the project, it became apparent that the definition of what exactly the incipient phase of a fire encompasses is not definite and depends on the disciplines dealing with the subject ‘fire’. Based on the results of a literature review, an inquiry under experts and laypersons as well as practical fire tests a definition for the phenomenon of the incipient fire was developed which divides it into four phases. Driving key factors for each phase are identified considering the main parameters to detect and extinguish the fire.
KW - Developing fires
KW - Development of fires
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-649310
DO - https://doi.org/10.1002/fam.70025
SN - 0308-0501
VL - 50
IS - 1
SP - 3
EP - 10
PB - Wiley
AN - OPUS4-64931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Marschall, Niklas
A1 - Niebergall, Ute
A1 - Böhning, Martin
T1 - FAIR data in mechanical testing of polymers: Implementation of the full-notch creep test ontology (OntoFNCT)
N2 - The ongoing digitalization trend has fostered a significant shift in polymer science and engineering towards increased utilization of digital methods. The integration and reuse of data across materials synthesis, production, characterization, and modeling leads to enhanced innovation. Recognizing the importance of FAIR data principles, OntoFNCT is introduced as an ontology specifically tailored to represent data from full notch creep tests (FNCT) in the interoperable RDF format. FNCT is a method for assessing polymer material behavior under defined stress and environmental conditions. OntoFNCT is aligned with the corresponding ISO 16770 standard and enriches FNCT data with Semantic technologies (ST). Using OntoFNCT, data exchange among stakeholders is facilitated while enhancing speed, precision, and reliability in material evaluation and quality control processes. The integration with higher-level ontologies promotes interoperability and reusability of FNCT data across diverse sources. Additionally, an automated Python-based analysis workflow tailored to FAIR RDF graph data obtained through SPARQL queries was developed to determine FNCT characteristic values. Its usability was successfully demonstrated through its application to real FNCT datasets with correct automated RDF conversion for all test records without data loss and reduced manual analysis time by approximately 60% compared to traditional spreadsheet-based evaluation.
KW - Semantic technologies
KW - Domain ontology development
KW - Full-notch creep test (FNCT)
KW - Environmental stress cracking (ESC)
KW - Data interoperability
KW - Semantically integrated FAIR data
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659674
DO - https://doi.org/10.1016/j.rineng.2026.110549
SN - 2590-1230
VL - 30
SP - 1
EP - 17
PB - Elsevier BV
CY - Amsterdam
AN - OPUS4-65967
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fardan, Ahmed
A1 - Schröder, Jakob
A1 - Xu, Jinghao
A1 - Brodin, Håkan
A1 - Hryha, Eduard
T1 - Role of scan strategies in modulating micro and macro-cracking in CM247LC processed by powder bed fusion–laser beam
N2 - This study investigates the influence of different scan strategies, specifically scan rotation (0°, 67°, and 90°) and remelting (Double 67° and Double 90°), on the microstructure evolution, residual stress distribution, cracking behavior and mechanical properties of CM247LC superalloy fabricated by powder bed fusion–laser beam (PBF–LB). Scan strategy significantly impacts micro-cracking susceptibility, crystallographic texture, and residual stress distribution. The micro-cracking which is confirmed as solidification cracking occurred in high angle grain boundaries. The micro-cracking decreased progressively from ~2.50 mm/mm2 (0° strategy) to ~0.30 mm/mm2 (Double 90°), accompanied by improved strength-ductility synergy. The micro-cracking reduction was attributed to promotion of <100> crystallographic texture along build direction and a ~20% decrease in high angle grain boundary fraction. Post heat-treatment macro-cracking in cruciform geometry, was found to be influenced by residual stress distribution and as-built microstructure. Remelted samples with higher residual stress (808 MPa along build direction for Double 90°) exhibited severe macro-cracking (19.66 mm), whereas the 0° strategy with moderate residual stress (729 MPa along build direction) underwent minimal macro-cracking (2.15 mm). Macro-cracking in most strategies (67°, 90°, Double 67°, and Double 90°) occurred near stress concentrator notches of the cruciform, however the 0° strategy exhibited an anomalous cracking pattern, with macro-cracking occurring transverse to melt tracks at the top surface of the cruciform. This work demonstrates the critical importance of controlling residual stress formation through scan strategy optimization to obtain defect-free heat-treated CM247LC components produced by PBF–LB.
KW - Scan strategies
KW - Remelting
KW - Solidification cracking
KW - Strain age cracking
KW - CM247LC
KW - Residual stress
KW - Powder bed fusion–laser beam
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659843
DO - https://doi.org/10.1007/s40964-026-01701-z
SN - 2363-9512
SP - 1
EP - 17
PB - Springer International Publishing
CY - Cham
AN - OPUS4-65984
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shabdali, G. A.
A1 - Wandtke, K.
A1 - Schroepfer, D.
A1 - Kromm, A.
A1 - Scharf-Wildenhain, R.
A1 - Haelsig, A.
A1 - Kannengiesser, T.
A1 - Hensel, J.
T1 - Comparative residual stress analysis on a DED-Arc manufactured high-strength steel component using the contour method and XRD
N2 - Lightweight construction is a vital approach for reducing CO₂ emissions, as it contributes to the development of more energy-efficient structures and supports the overall goal of achieving carbon neutrality in the transition to sustainable manufacturing. Though, a topology-optimized design often leads to complex geometries. Additive manufacturing (AM) processes such as direct energy deposition with arc (DED-Arc) offer great design freedom due to the buildup of components in layers. Furthermore, DED-Arc enables efficient production due to the high deposition rate, process reliability, and good automation capability. Further efficiency can be achieved through weight optimization, enabled by high-strength steels. However, a major challenge is the process-induced residual stresses (RS) in the component, which arise primarily due to restrained shrinkage. High tensile residual stresses are detrimental as they increase the risk for several types of cracking and failures. Knowledge of residual stress distribution is crucial for predicting the service life of the component and structural integrity assessment, especially for safety-critical applications. Therefore, this study focuses on the use of the contour method (CM) to analyze the full field longitudinal residual stresses in an open hollow cuboid component (dimensions, 120 × 50 × 30 mm
3
) manufactured by DED-Arc (low-alloyed high-strength steel with yield strength 730 MPa). In CM, the component is cut along a desired plane of interest, and the contour of the deformed cut surface is measured. A finite element model is used to reconstruct the residual stresses field in the 2-dimensional plane of cut. In this paper, a modified cutting strategy was employed. After cutting, the deformed cut surfaces were measured utilizing two surface measurement techniques, i.e., coordinate measuring machine (CMM) and a 3D scanner. The accuracy of the CM was validated against surface stresses measured using X-ray diffraction (XRD). Additionally, a comparison of neutron diffraction experiments was conducted. The residual stresses were further correlated with hardness measurements. The results from surface measurement techniques showed good qualitative and quantitative agreement regarding the measured displacement contour. CM results revealed peak stresses in the DED-Arc walls; bending deformation in the substrate induces tensile stresses at the bottom of the substrate plate and compressive stresses in the middle top region. The residual stresses obtained from diffraction and CM showed a good agreement and correlated qualitatively with the hardness measurements. These results show that practical residual stress mapping and quantification using XRD accompanied by minimal application of CM for values in the bulk are suitable for identifying and minimizing detrimental welding-induced stresses in such high-strength AM lightweight components, even without the use of expensive methods such as neutron diffraction.
T2 - 78. IIW Annual Assembly
CY - Genoa, Italy
DA - 22.06.2025
KW - Residual stress
KW - Contour method
KW - DED-Arc/M
KW - Additive Manufacturing
KW - High-strength steel
KW - Filler metals
KW - XRD
KW - Neutron diffraction
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659881
DO - https://doi.org/10.1007/s40194-026-02441-y
SN - 0043-2288
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
CY - Berlin ; Heidelberg
AN - OPUS4-65988
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Xu, Zhen
A1 - Yoshii, Takeharu
A1 - Nishihara, Hirotomo
A1 - Titirici, Maria-Magdalena
A1 - Forse, Alexander
A1 - Shimizu, Shunsuke
A1 - Pedersen, Angus
A1 - Barrio, Jesús
T1 - Exploring Improved Supercapacitor Electrodes for Electrochemical Carbon Dioxide Capture
N2 - This study introduces a new porous carbon for electrochemical CO2 capture. Featuring both micro- and mesoporosity, it outperforms predominantly microporous YP80F (a commercial benchmark) by delivering faster CO2 adsorption and lower energy consumption. This highlights the importance of mesoporosity in designing improved supercapacitor electrodes for rapid, energy-efficient electrochemical CO2 capture.
KW - Electrochemical CO2 Capture
KW - Supercapacitor
KW - Porous Carbon
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659855
DO - https://doi.org/10.1021/acselectrochem.6c00086
SN - 2997-0571
SP - 6
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-65985
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brunner, Nanine
A1 - Thomas, Marcus
A1 - Deuber, Dominic
A1 - Tiebe, Carlo
A1 - Melzer, Michael
T1 - Towards fully automated metrological traceability in process monitoring: a demonstrator approach highlighting the benefits of Digital Calibration Certificates (DCCs)
N2 - Abstract. The implementation of automation in the metrological traceability of measurements has been demonstrated to possess considerable potential for enhancing the effectiveness of quality management. This enhancement is achieved by decreasing the necessity for human interaction and reducing the risks associated with manual data processing. For this purpose, it is imperative that all metrological and administrative information in quality certificates be provided in a fully machine-readable and machine-interpretable form. The transition from paper-based calibration certificates to Digital Calibration Certificates (DCCs), which meet these requirements, enables a fully automatic process conformity monitoring system. A demonstrator that monitors the temperature of a process has been developed as an example to illustrate the potential for automation that accompanies the use of DCCs, including in security. The programming code is also published to give a starting point for the reader's own implementation.
T2 - SMSI 2025
CY - Nuremberg, Germany
DA - 05.05.2025
KW - DCC
KW - QI Digital
KW - Demonstrator
KW - Temperatur
KW - XML
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659898
DO - https://doi.org/10.5194/jsss-15-77-2026
SN - 2194-878X
VL - 15
IS - 1
SP - 77
EP - 87
PB - Copernicus Publ.
CY - Göttingen
AN - OPUS4-65989
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asres, Nahom Enkubahri
A1 - Cabello, Marta
A1 - Tufail, Muhammad Khurram
A1 - Castresana, Kerman Gomez
A1 - Villaverde, Aitor
A1 - López del Amo, Juan Miguel
T1 - Solid-State NMR Investigation of Electrolyte Effects on Silicon–Graphite Composite Anode: Solid Electrolyte Interphase Formation and Failure Mechanisms
N2 - Silicon (Si) is a promising anode material due to its high specific capacity (~3,580 mAh g⁻¹), far exceeding that of graphite (~372 mAh g⁻¹). However, its large volumetric expansion (~300%) during lithiation induces mechanical stress, fracturing particles and repeatedly exposing fresh surfaces to the electrolyte. This leads to continuous SEI growth, consuming lithium and electrolyte and causing rapid capacity fading. To address these issues, strategies such as incorporating Si into graphite (Gr) composites and optimizing electrolytes have shown promise in improving the stability and performance of Si-based anodes. NMR spectroscopy offers element-specific sensitivity and can probe local chemical environments, making it a powerful tool for examining both surface and bulk properties of battery materials. In this work, we use solid-state NMR spectroscopy to investigate Si/Gr anodes in two systematically chosen electrolytes: one EC-based (known to form organic-rich SEI) and one FEC-based (inorganic-rich SEI). We conducted 1D 7Li, 19F, and 1H NMR experiments to elucidate the lithiation mechanism and identify SEI components in Si/Gr composite anodes during the first cycle and after extended cycling in the fully lithiated state for these two electrolyte systems. Additionally, we performed cross-polarization (CP) and two-dimensional exchange spectroscopy (EXSY) NMR experiments to gain deeper insight into Li⁺ coordination within different SEI components and to probe dynamic exchange processes between the SEI and lithiated Si/Gr phases (LixSi/LixC6). A novel approach 1H/19F→7Li CP-MAS EXSY NMR was employed to selectively probe Li⁺ exchange originating from either the organic or the inorganic fraction of the SEI. These NMR results were correlated with the electrochemical performance of the Si/Gr anode in both electrolyte systems.
KW - Silicon anode
KW - Electrolytes
KW - Solid-state NMR Spectroscopy
KW - Li-ion battery
KW - Solid Electrolyte Interphase (SEI)
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-659974
DO - https://doi.org/10.1021/acs.chemmater.5c02476
SN - 0897-4756
SP - 1
EP - 16
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-65997
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -