TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
A1 - Krebber, Katerina
T1 - Distributed acoustic sensing to monitor ground motion/movement at multi-frequency bands
JF - Journal of Lightwave Technology
N2 - A novel distributed acoustic sensing technique is proposed that exploits both phase and amplitude of the Rayleigh backscattered light to quantify the environmental variation. The system employs a wavelength-scanning laser and an imbalanced Mach-Zehnder interferometer to acquire the reflection spectra and the phase of the detected light, respectively. Fading-free and low-frequency measurements are realized via the crosscorrelation of the reflection spectra. The discrete crosscorrelation is used to circumvent the nonlinear frequency sweeping of the laser. Based on the phase of the backscattered light, it is possible to quantify fast environmental variations. The whole system requires no hardware modification of the existing system and its functionality is experimentally validated. The proposed system has the potential to monitor ground motion/movement at very low frequency band like subsidence around mining areas and at high frequency band like earthquakes and vibrations induced by avalanches.
KW - Distributed acoustic sensing
KW - DAS
KW - Distributed fiber optic sensing
KW - Ground motion detection
KW - Subsidence monitoring
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596129
DO - https://doi.org/10.1109/JLT.2024.3358495
SP - 1
EP - 8
PB - Optical Society und IEEE Photonics Society
AN - OPUS4-59612
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Trogadas, P.
A1 - Cho, J. I. S.
A1 - Rasha, L.
A1 - Lu, X.
A1 - Kardjilov, N.
A1 - Markötter, Henning
A1 - Manke, I.
A1 - Shearing, P. R.
A1 - Brett, D. J. L.
A1 - Coppens, M. O.
T1 - A nature-inspired solution for water management in flow fields for electrochemical devices
JF - Energy & Environmental Science
N2 - A systematic, nature-inspired chemical engineering approach is employed to solve the issue of flooding in electrochemical devices. The mechanism of passive water transport utilized by lizards living in arid environments is leveraged to design flow-fields with a microchannel structure on their surface, through which capillary pressure rapidly removes the water generated in the electrochemical device. This water management strategy is implemented in proton exchange membrane fuel cells (PEMFCs) with a lunginspired flow-field, which ensures uniform distribution of reactants across the catalyst layer. Jointly, this nature-inspired approach results in flood-free, stable operation at 100% RH and a B60% increase in current (B1.9 A cm-2) and peak power density (B650 mW cm−2) compared to current PEMFCs with a flood-prone, serpentine flow-field (B0.8 A cm-2 and 280 mW cm-2, respectively). This significant advance allows for PEMFC operation at fully humidified conditions.
KW - Neutron imaging
KW - X-ray tomography
KW - Fuel cell
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596662
DO - https://doi.org/10.1039/d3ee03666a
VL - 17
SP - 2007
EP - 2017
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59666
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Emamverdi, Farnaz
A1 - Huang, J.
A1 - Szymoniak, Paulina
A1 - Bojdys, M. J.
A1 - Böhning, Martin
A1 - Schönhals, Andreas
T1 - Structure and molecular mobility of phosphinine-based covalent organic frameworks – glass transition of amorphous COFs
JF - Materials Advances
N2 - Two-dimensional covalent organic frameworks (COFs) based on phosphinine and thiophene building blocks have been synthesized with two different side groups. The materials are denoted as CPSF-MeO and CPSF-EtO where CxxF correspond to the covalent framework, whereas P and S are related to heteroatoms phosphorous and sulfur. MeO and EtO indicate the substituents, i.e. methoxy and ethoxy.
Their morphologies were studied by scanning electron microcopy and X-ray scattering. The absence of crystalline reflexes in the X-ray pattern reveal that both materials are amorphous and can be considered as glasses. Furthermore, N2 adsorption measurements indicate substantial Brunauer–Emmett–Teller (BET) surface area values pointing to the formation of three-dimensional pores by stacking of the aromatic 2D layer. An analysis of the porosity of both COFs showed a mean radius of the pores to be of ca. 4 nm, consistent with their chemical structure. The COFs form nanoparticles with a radius of around 100 nm. The thermal behavior of the COFs was further investigated by fast scanning calorimetry. These investigations showed that both COFs undergo a glass transition. The glass transition temperature of CPSF-EtO is found to be ca. 100 K higher than that for CPSF-MeO. This large difference in the glass transition is discussed to be due to a change in the interaction of the COF sheets induced by the longer ethoxy group. It might be assumed that for CPSF-EtO more individual COF sheets assemble to larger stacks than for CPSF-MeO. This agrees with the much larger surface area value found for CPSF-EtO compared to CPSF-MeO. To corroborate the results obtained be fast scanning calorimetry dielectric measurements were conducted which confirm the occurrence of a dynamic glass transition. The estimated temperature dependence of the relaxation rates of the dielectric relaxation and their absolute values agrees well with the data obtained by fast scanning calorimetry. Considering the fragility approach to the glass transition, it was further found that CPSF-MeO is a fragile glass former whereas CPSF-EtO behaves as a strong glass forming material. This difference in the fragility points also to distinct differences in the interaction between the 2D COF molecules in both materials.
KW - Covalent Organic frameworks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596770
DO - https://doi.org/10.1039/d3ma01123b
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59677
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Syntheses of Polyglycolide via Polycondensation: A Reinvestigation
JF - Macromolecular Chemistry and Physics
N2 - The Na salt of chloroacetic acid is condensed in suspension. Furthermore,glycolic acid is condensed in bulk or in concentrated solution by means of SnCl2 or 4-toluene sulfonic acid (TSA) as catalysts. The temperatures are varied from 160 to 200°C and the time from 1 to 5 days. Low molar mass cyclic poly(glycolic acid) (PGA) is detected by means of matrix-assisted laser desorption ionization time-of-flight (MALDI TOF) mass spectrometry in most PGAs. A predominance of certain cycles having an even number of repeat units is observed suggesting a thermodynamically favored formation of extended-ring crystals. Extremely high melting temperatures (up to 237.5°C)and high melting enthalpies are found for polycondensations with TSA in 1,2-dichlorobenzene.
KW - MALDI TOF MS
KW - Polycondensation
KW - Polyglycolide
KW - Cyclization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596856
DO - https://doi.org/10.1002/macp.202300397
IS - 2300397
SP - 1
EP - 7
PB - Wiley VHC-Verlag
AN - OPUS4-59685
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H.
T1 - Cyclic polyglycolides via ring-expansion polymerization with cyclic tin catalysts
JF - European Polymer Journal
N2 - Glycolide was polymerized in bulk with two cyclic catalysts − 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzepane (SnBiph). The monomer/initiator ratio, temperature (140 – 180 °C) and time (1–––4 days) were varied. The MALDI TOF mass spectra exclusively displayed peaks of cyclic polyglycolide (PGA) and revealed an unusual “saw-tooth pattern” in the mass range below m/z 2 500 suggesting formation of extended ring crystallites. The DSC measurements indicated increasing crystallinity with higher temperature and longer time, and after annealing for 4 d at 160 °C a hitherto unknown and unexpected glass transition was found in the temperature range of 170–185 °C. Linear PGAs prepared by means of metal alkoxides under identical conditions did not show the afore-mentioned features of the cyclic PGAs, neither in the mass spectra nor in the DSC measurements. All PGAs were also characterized by SAXS measurements, which revealed relatively small L-values suggesting formation of thin crystallites in all cases with little influence of the reaction conditions.
KW - Polyglycolide
KW - MALDI-TOF MS
KW - Ring-expansion polymerization
KW - Crystals
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595541
DO - https://doi.org/10.1016/j.eurpolymj.2024.112811
SN - 0014-3057
VL - 207
SP - 1
EP - 9
PB - Elsevier Ltd.
AN - OPUS4-59554
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tukhmetova, Dariya
A1 - Lisec, Jan
A1 - Vogl, Jochen
A1 - Meermann, Björn
T1 - Development of an Online Isotope Dilution CE/ICP–MS Method for the Quantification of Sulfur in Biological Compounds
JF - Analytical Chemistry
N2 - We report an analytical methodology for the quantification of sulfur in biological molecules via a speciesunspecific postcolumn isotope dilution (online ID) approach using capillary electrophoresis (CE) coupled online with inductively coupled plasma−mass spectrometry (online ID CE/ICP−MS).
The method was optimized using a mixture of standard compounds including sulfate, methionine, cysteine, cystine, and albumin, yielding compound recoveries between 98 and 105%. The quantity of sulfur is further converted to the quantity of the compounds owing to the prior knowledge of the sulfur content in the molecules. The limit of detection and limit of quantification of sulfur in the compounds were 1.3−2.6 and 4.1−8.4 mg L−1, respectively, with a correlation coefficient of 0.99 within the concentration range of sulfur of 5−100 mg L−1. The capability of the method was extended to quantify albumin in its native matrix (i.e., in serum) using experimentally prepared serum spiked with a pure albumin standard for validation. The relative expanded uncertainty of the method for the quantification of albumin was 6.7% (k = 2). Finally, we tested the applicability of the method on real samples by the analysis of albumin in bovine and human sera. For automated data assessment, a software application (IsoCor) which was developed by us in a previous work was developed further for handling of online ID data. The method has several improvements compared to previously published setups: (i) reduced adsorption of proteins onto the capillary wall owing to a special capillary-coating procedure, (ii) baseline separation of the compounds in less than 30 min via CE, (iii) quantification of several sulfur species within one run by means of the online setup, (iv) SI traceability of the quantification results through online ID, and (v) facilitated data processing of the transient signals using the IsoCor application. Our method can be used as an accurate approach for quantification of proteins and other biological molecules via sulfur analysis in complex matrices for various fields, such as environmental, biological, and pharmaceutical studies as well as clinical diagnosis.
Sulfur is an essential element in living organisms, where it plays important roles in various biological processes, such as protein synthesis, enzyme activity, and antioxidant defense. However, the biological effects of different sulfur species can vary widely, and imbalances in sulfur speciation have been observed in a range of diseases, including cancer, Alzheimer’s disease, and diabetes.1−3 The accurate quantification of sulfur and its species in biological samples requires sensitive and selective analytical techniques. In recent years, separation techniques coupled online with inductively coupled plasma−mass spectrometry (ICP−MS) have emerged as powerful online analytical tools complementary to molecular spectrometric methods for speciation analysis of biological compounds.
External calibration4−9 and isotope dilution (ID)10−15 are common calibration approaches applied for online quantification of sulfur species in complex samples. The ID analysis is advantageous over.
KW - Analytical Chemistry
KW - CE/MC-ICP-MS
KW - species-specific isotope information
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594736
DO - https://doi.org/10.1021/acs.analchem.3c03553
SN - 0003-2700
SP - 1
EP - 8
PB - American Chemical Society (ACS)
AN - OPUS4-59473
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Prabhakara, Prathik
A1 - Lay, Vera
A1 - Mielentz, Frank
A1 - Niederleithinger, Ernst
A1 - Behrens, Matthias
T1 - Enhancing the Performance of a Large Aperture Ultrasound System (LAUS): A Combined Approach of Simulation and Measurement for Transmitter–Receiver Optimization
JF - Enhancing the Performance of a Large Aperture Ultrasound System (LAUS): A Combined Approach of Simulation and Measurement for Transmitter–Receiver Optimization
N2 - The Large Aperture Ultrasound System (LAUS) developed at BAM is known for its ability to penetrate thick objects, especially concrete structures commonly used in nuclear waste storage and other applications in civil engineering. Although the current system effectively penetrates up to ~9 m, further optimization is imperative to enhance the safety and integrity of disposal structures for radioactive or toxic waste. This study focuses on enhancing the system’s efficiency by optimizing the transducer spacing, ensuring that resolution is not compromised. An array of twelve horizontal shear wave transducers was used to find a balance between penetration depth and resolution. Systematic adjustments of the spacing between transmitter and receiver units were undertaken based on target depth ranges of known reflectors at depth ranges from 5 m to 10 m. The trade-offs between resolution and artifact generation were meticulously assessed. This comprehensive study employs a dual approach using both simulations and measurements to investigate the performance of transducer units spaced at 10 cm, 20 cm, 30 cm, and 40 cm. We found that for depths up to 5 m, a spacing of 10 cm for LAUS transducer units provided the best resolution as confirmed by both simulations and measurements. This optimal distance is particularly effective in achieving clear reflections and a satisfactory signal-to-noise ratio (SNR) in imaging scenarios with materials such as thick concrete structures. However, when targeting depths greater than 10 m, we recommend increasing the distance between the transducers to 20 cm. This increased spacing improves the SNR in comparison to other spacings, as seen in the simulation of a 10 m deep backwall. Our results emphasize the critical role of transducer spacing in achieving the desired SNR and resolution, especially in the context of depth imaging requirements for LAUS applications. In addition to the transducer spacing, different distances between individual sets of measurement positions were tested. Overall, keeping the minimal possible distance between measurement position offsets provides the best imaging results at greater depths. The proposed optimizations for the LAUS in this study are primarily relevant to applications on massive nuclear structures for nuclear waste management. This research highlights the need for better LAUS efficiency in applications such as sealing structures, laying the foundation for future technological advances in this field.
KW - Engineered barrier system
KW - Phased array technique
KW - Ultrasonic testing
KW - Non-destructive testing in civil engineering
KW - Seismic migration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592426
DO - https://doi.org/10.3390/s24010100
VL - 24
IS - 1
SP - 1
EP - 23
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-59242
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Meyer, A.
T1 - Syntheses of high molecular mass polyglycolides via ring-opening polymerization with simultaneous polycondensation(ROPPOC) by means of tin and zinc catalysts
JF - Polymers for Advanced Technologies
N2 - Glycolide was polymerized in bulk by means of four different ROPPOC catalysts: tin(II) 2-ethylhexanoate (SnOct2), dibutyltin bis(pentafluoro-phenoxide) (BuSnOPF),zinc biscaproate (ZnCap), and zinc bis(pentafluoro-phenyl sulfide) (ZnSPF). The temperature was varied between 110 and 180°C and the time between 3 h and 7 days. For the few polyglycolides (PGAs) that were soluble extremely high molecular masses were obtained. The MALDI TOF mass spectra had all a low signal-to-noise ration and displayed the peaks of cyclic PGAs with a“saw-tooth pattern ”indicating formation of extended-ring crystallites in the mass range below m/z 2500. The shape of DSC curves varied considerably with catalyst and reaction conditions, whereas the long-distance values measured by SAXS were small and varied little with the polymeriza-tion conditions.
KW - MALDI TOF MS
KW - Polyglycolide
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598221
DO - https://doi.org/10.1002/pat.6365
VL - 35
IS - 4
SP - 1
EP - 10
PB - John Wiley & Sons Ltd.
AN - OPUS4-59822
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Thiele, Isabel
A1 - Santolin, Lara
A1 - Meyer, Klas
A1 - Machatschek, Rainhard
A1 - Bölz, Uwe
A1 - Tarazona, Natalia A.
A1 - Riedel, Sebastian L.
T1 - Microbially synthesized poly(hydroxybutyrate-co-hydroxyhexanoate) with low to moderate hydroxyhexanoate content: Properties and applications
JF - International Journal of Biological Macromolecules
N2 - Plastic pollution is the biggest environmental concern of our time. Breakdown products like micro- and nanoplastics inevitably enter the food chain and pose unprecedented health risks. In this scenario, bio-based and biodegradable plastic alternatives have been given a momentum aiming to bridge a transition towards a more sustainable future. Polyhydroxyalkanoates (PHAs) are one of the few thermoplastic polymers synthesized 100 % via biotechnological routes which fully biodegrade in common natural environments. Poly(hydroxybutyrate-cohydroxyhexanoate) [P(HB-co-HHx)] is a PHA copolymer with great potential for the commodity polymers industry, as its mechanical properties can be tailored through fine-tuning of its molar HHx content. We have recently developed a strategy that enables for reliable tailoring of the monomer content of P(HB-co-HHx).
Nevertheless, there is often a lack of comprehensive investigation of the material properties of PHAs to evaluate whether they actually mimic the functionalities of conventional plastics. We present a detailed study of P(HB-co-HHx) copolymers with low to moderate hydroxyhexanoate content to understand how the HHx monomer content influences the thermal and mechanical properties and to link those to their abiotic degradation. By increasing the HHx fractions in the range of 2 – 14 mol%, we impart an extension of the processing window and application range as the melting temperature (Tm) and glass temperature (Tg) of the copolymers decrease from Tm 165 ◦C to 126 ◦C, Tg 4 ◦C to − 5.9 ◦C, accompanied by reduced crystallinity from 54 % to 20 %.
Elongation at break was increased from 5.7 % up to 703 % at 14 mol% HHx content, confirming that the range examined was sufficiently large to obtain ductile and brittle copolymers, while tensile strength was maintained throughout the studied range. Finally, accelerated abiotic degradation was shown to be slowed down with an increasing HHx fraction decreasing from 70 % to 55 % in 12 h.
KW - Molecular Biology
KW - General Medicine
KW - Biochemistry
KW - Structural Biology
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595636
DO - https://doi.org/10.1016/j.ijbiomac.2024.130188
VL - 263
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-59563
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos Collado, José Antonio
A1 - Balderas‐Xicohténcatl, Rafael
A1 - Al Shakhs, Ali N.
A1 - Berenguer‐Murcia, Ángel
A1 - Buckley, Craig E.
A1 - Cazorla‐Amorós, Diego
A1 - Charalambopoulou, Georgia
A1 - Couturas, Fabrice
A1 - Cuevas, Fermin
A1 - Fairen‐Jimenez, David
A1 - Heinselman, Karen N.
A1 - Humphries, Terry D.
A1 - Kaskel, Stefan
A1 - Kim, Hyunlim
A1 - Marco‐Lozar, Juan P.
A1 - Oh, Hyunchul
A1 - Parilla, Philip A.
A1 - Paskevicius, Mark
A1 - Senkovska, Irena
A1 - Shulda, Sarah
A1 - Silvestre‐Albero, Joaquin
A1 - Steriotis, Theodore
A1 - Tampaxis, Christos
A1 - Hirscher, Michael
A1 - Maiwald, Michael
T1 - Establishing ZIF‐8 as a reference material for hydrogen cryoadsorption: An interlaboratory study
JF - ChemPhysChem
N2 - AbstractHydrogen storage by cryoadsorption on porous materials has the advantages of low material cost, safety, fast kinetics, and high cyclic stability. The further development of this technology requires reliable data on the H2 uptake of the adsorbents, however, even for activated carbons the values between different laboratories show sometimes large discrepancies. So far no reference material for hydrogen cryoadsorption is available. The metal‐organic framework ZIF‐8 is an ideal material possessing high thermal, chemical, and mechanical stability that reduces degradation during handling and activation. Here, we distributed ZIF‐8 pellets synthesized by extrusion to 9 laboratories equipped with 15 different experimental setups including gravimetric and volumetric analyzers. The gravimetric H2 uptake of the pellets was measured at 77 K and up to 100 bar showing a high reproducibility between the different laboratories, with a small relative standard deviation of 3–4 % between pressures of 10–100 bar. The effect of operating variables like the amount of sample or analysis temperature was evaluated, remarking the calibration of devices and other correction procedures as the most significant deviation sources. Overall, the reproducible hydrogen cryoadsorption measurements indicate the robustness of the ZIF‐8 pellets, which we want to propose as a reference material.
KW - Physical and theoretical chemistry
KW - Atomic and molecular physics, and optics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594788
DO - https://doi.org/10.1002/cphc.202300794
SN - 1439-7641
SP - 1
EP - 7
PB - Wiley
CY - Weinheim
AN - OPUS4-59478
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Maack, Stefan
T1 - Improving onset picking in ultrasonic testing by using a spectral entropy criterion
JF - The Journal of the Acoustical Society of America
N2 - In ultrasonic testing, material and structural properties of a specimen can be derived from the time-of-flight (ToF). Using signal features, such as the first peak or envelope maximum, to calculate the ToF is error-prone in multipath arrangements or dispersive and attenuating materials, which is not the case for the signal onset. Borrowing from seismology, researchers used the Akaike information criterion (AIC) picker to automatically determine onset times. The most commonly used formulation, Maeda's AIC picker, is reassessed and found to be based on inappropriate assumptions for signals often used in ultrasonic testing and dependent on arbitrary parameters. Consequently, an onset picker for ultrasonic through-transmission measurements is proposed, based on a spectral entropy criterion (SEC) to model the signal using the AIC framework. This SEC picker takes into account the spectral properties of the ultrasonic signal and is virtually free of arbitrary parameters. Synthetic and experimental data are used to compare the performance of SEC and AIC pickers. It is shown that the accuracy of onset picking is improved for densely sampled data.
KW - Akaike information criterion picker
KW - Nondestructive testing
KW - Ultrasound
KW - Time of flight
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594284
UR - https://pubs.aip.org/asa/jasa/article/155/1/544/3061576/Improving-onset-picking-in-ultrasonic-testing-by
DO - https://doi.org/10.1121/10.0024337
SN - 0001-4966
VL - 155
IS - 1
SP - 544
EP - 554
PB - AIP Publishing
CY - Melville, NY, USA
AN - OPUS4-59428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Timofeev, Juri
A1 - Azari, H.
A1 - Satyanarayana, R.
T1 - Controlled Creating of Delaminations in Concrete for Nondestructive Testing
JF - Journal of Nondestructive Evaluation
N2 - Locating and sizing delaminations is a common inspection task in the maintenance and quality control of construction and rehabilitation. Their detection is an important area of application of nondestructive testing in civil engineering (NDT-CE). To improve this application, NDT test systems and test solutions must be compared, for which specimens containing well-defined delaminations are needed to serve as a reference. Currently, there are no widely accepted procedures available for creating such flaws locally and reproducibly. This study presents procedures for creating artificial delaminations repeatably and as close as possible to natural delaminations. To produce the discontinuities only substances were used which can occur in concrete components and do not affect the application of NDT-CE methods. Ultrasonic pulse-echo (UPE) was used to test the flaws in the specimens. The delaminations were created by applying expansive mortar in prepared through holes. Three specimens with two delaminations each were built and tested using UPE.
KW - Concrete
KW - Reference
KW - Delamination
KW - Test specimen
KW - Non-destructive testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595201
DO - https://doi.org/10.1007/s10921-023-01044-7
SN - 0195-9298
VL - 43
IS - 1
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-59520
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Maack, Stefan
A1 - Strangfeld, Christoph
T1 - Fluidic Ultrasound Generation for Non‐Destructive Testing
JF - Advanced Materials
N2 - AbstractAir‐coupled ultrasonic testing (ACU) is a pioneering technique in non‐destructive testing (NDT). While contact testing and fluid immersion testing are standard methods in many applications, the adoption of ACU is progressing slowly, especially in the low ultrasonic frequency range. A main reason for this development is the difficulty of generating high amplitude ultrasonic bursts with equipment that is robust enough to be applied outside a laboratory environment. This paper presents the fluidic ultrasonic transducer as a solution to this challenge. This novel aeroacoustic source uses the flow instability of a sonic jet in a bistable fluidic switch to generate ultrasonic bursts up to 60 kHz with a mean peak pressure of 320 Pa. The robust design allows operation in adverse environments, independent of the operating fluid. Non‐contact through‐transmission experiments are conducted on four materials and compared with the results of conventional transducers. For the first time, it is shown that the novel fluidic ultrasonic transducer provides a suitable acoustic signal for NDT tasks and has potential of furthering the implementation of ACU in industrial applications.This article is protected by copyright. All rights reserved
KW - Aeroacoustics
KW - Air-coupled ultrasound
KW - Fluidics
KW - Harsh environment
KW - Laser Doppler vibrometer
KW - Non-destructive testing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594273
DO - https://doi.org/10.1002/adma.202311724
SN - 0935-9648
SP - 1
EP - 14
PB - Wiley
AN - OPUS4-59427
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Grohmann, Maria
A1 - Niederleithinger, Ernst
A1 - Maack, Stefan
A1 - Buske, Stefan
T1 - Application of iterative elastic SH reverse time migration to synthetic ultrasonic echo data
JF - Journal of nondestructive evaluation
N2 - The ultrasonic echo technique is widely used in non-destructive testing (NDT) of concrete objects for thickness measurements, geometry determinations and localization of built-in components. To improve ultrasonic imaging of complex concrete structures, we transferred a seismic imaging technique, the Reverse Time Migration (RTM), to NDT in civil engineering. RTM, in contrast to the conventionally used synthetic aperture focusing technique (SAFT) algorithms, considers all wavefield types and thus, can handle complex wave propagations in any direction with no limit on velocity variations and reflector dip. In this paper, we focused on the development, application and evaluation of a two-dimensional elastic RTM algorithm considering horizontally polarized shear (SH) waves only. We applied the elastic SH RTM routine to synthetic ultrasonic echo SH-wave data generated with a concrete model incorporating several steps and circular cavities. As these features can often be found in real-world NDT use cases, their imaging is extremely important. By using elastic SH RTM, we were able to clearly reproduce almost all reflectors inside the concrete model including the vertical step edges and the cross sections of the cavities.We were also capable to show that more features could be mapped compared to SAFT, and that imaging of complex reflectors could be sharpened compared to elastic P-SV (compressional-vertically polarized shear) RTM. Our promising results illustrate that elastic SH RTM has the potential to significantly enhance the reconstruction of challenging concrete structures, representing an important step forward for precise, high-quality ultrasonic NDT in civil engineering.
KW - Ultrasonic echo technique
KW - Concrete structures
KW - Elastic reverse time migration
KW - Synthetic aperture focusing technique
KW - Horizontally polarized shear waves
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-591716
DO - https://doi.org/10.1007/s10921-023-01010-3
SN - 1573-4862
VL - 43
SP - 1
EP - 16
PB - Springer Science and Business Media
CY - Dordrecht
AN - OPUS4-59171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schröpfer, Dirk
A1 - Witte, Julien
A1 - Kromm, Arne
A1 - Kannengießer, Thomas
T1 - Stresses in repair welding of high-strength steels—part 1: restraint and cold cracking risk
JF - Welding in the World
N2 - AbstractThe sustainable and resource-efficient production of wind energy plants requires the use of modern high-strength fine-grain structural steels. This applies to both foundation and erection structures, like mobile or ship cranes. During the assembly of steel structures, unacceptable defects can occasionally be found in the weld area. In most cases, the economical solution would be local thermal gouging of the affected areas and re-welding. Due to the high shrinkage restraint of the joint groove in the overall structure, the superposition of global and local welding-induced stresses may lead to crack formation and component failure, particularly in interaction with the degradation of the microstructure and mechanical properties of high-strength steels during the repair process. However, manufacturers hardly have any information about these issues and there is a lack of recommendations and guidelines to take these safety-relevant aspects into account in adequate repair concepts. The aim of this research is to derive recommendations for repair concepts appropriate to the stresses and materials involved providing a basis for standards and guidelines to avoid cold cracking, damage and expensive reworking especially for high-strength steels. Part 1 of this study involves systematic investigations of influences of shrinkage restraint during repair welding of two high-strength steels S500MLO for offshore application and S960QL for mobile crane structures. The quantification of the shrinkage restraint of repair weld joints was achieved by means of experimental and numerical restraint intensity analysis. In welding experiments with self-restrained slot specimens, restraint intensity and introduction of hydrogen via the welding arc using anti spatter spray were varied systematically to analyse the effect on welding result, residual stresses and cold cracking. It could be shown that increasing restraint intensities result in significantly higher transverse residual stress levels. In the case of hydrogen introduction S500MLO showed no cold cracking independent of the restraint conditions. However, S960QL was found to be considerably cold cracking sensitive if hydrogen is introduced. With increasing restraint intensity length and number of cold cracks increases significantly. Part 2 [1] of this study is focussed on microstructure and residual stresses due to gouging and stress optimization via adequate heat control parameters in repair welding.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595212
DO - https://doi.org/10.1007/s40194-024-01691-y
SN - 0043-2288
SP - 1
EP - 13
PB - Springer Science and Business Media LLC
AN - OPUS4-59521
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Konert, Florian
A1 - Wieder, Frank
A1 - Nietzke, Jonathan
A1 - Meinel, Dietmar
A1 - Böllinghaus, Thomas
A1 - Sobol, Oded
T1 - Evaluation of the impact of gaseous hydrogen on pipeline steels utilizing hollow specimen technique and μCT
JF - International Journal of Hydrogen Energy
N2 - The high potential of hydrogen as a key factor on the pathway towards a climate neutral economy, leads to rising demand in technical applications, where gaseous hydrogen is used. For several metals, hydrogen-metal interactions could cause a degradation of the material properties. This is especially valid for low carbon and highstrength structural steels, as they are commonly used in natural gas pipelines and analyzed in this work.
This work provides an insight to the impact of hydrogen on the mechanical properties of an API 5L X65 pipeline steel tested in 60 bar gaseous hydrogen atmosphere. The analyses were performed using the hollow specimen technique with slow strain rate testing (SSRT). The nature of the crack was visualized thereafter utilizing μCT imaging of the sample pressurized with gaseous hydrogen in comparison to one tested in an inert atmosphere.
The combination of the results from non-conventional mechanical testing procedures and nondestructive imaging techniques has shown unambiguously how the exposure to hydrogen under realistic service pressure influences the mechanical properties of the material and the appearance of failure.
KW - Energy Engineering and Power Technology
KW - Condensed Matter Physics
KW - Fuel Technology
KW - Renewable Energy, Sustainability and the Environment
KW - µCT
KW - Hollow Specimen Technique
KW - Hydrogen Embrittlement
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595077
DO - https://doi.org/10.1016/j.ijhydene.2024.02.005
SN - 0360-3199
VL - 59
SP - 874
EP - 879
PB - Elsevier B.V.
AN - OPUS4-59507
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Glienke, R.
A1 - Kalkowsky, F.
A1 - Hobbacher, A. F.
A1 - Holch, A.
A1 - Thiele, Marc
A1 - Marten, F.
A1 - Kersten, R.
A1 - Henkel, K.-M.
T1 - Evaluation of the fatigue resistance of butt‑welded joints in towers of wind turbines - A comparison of experimental studies with small scale and component tests as well as numerical based approaches with local concepts
JF - Welding in the world
N2 - Wind turbines are exposed to a high number of load cycles during their service lifetime. Therefore, the fatigue strength verification plays an important role in their design. In general, the nominal stress method is used for the fatigue verification of the most common used butt-welded joints. The Eurocode 3 part 1–9 is the current design standard for this field of application. This paper presents recent results of fatigue tests on small-scaled specimens and large components with transverse butt welds to discuss the validity of the FAT-class. Furthermore, results from numerical simulations for the verification with the effective notch stress and the crack propagation approach are used for comparison. Based on the consistency between the numerical results and the fatigue tests, the influence of the seam geometry on the fatigue resistance was investigated. Finally, a prediction of the fatigue strength of butt-welded joints with plate thicknesses up to 80 mm was carried out.
KW - Transverse butt weld
KW - Weld imperfections
KW - Wind turbine tower
KW - Fatigue strength
KW - Local approaches
KW - Large components
KW - Wind energy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596648
DO - https://doi.org/10.1007/s40194-023-01630-3
SN - 1878-6669
SP - 1
EP - 26
PB - Springer
CY - Berlin
AN - OPUS4-59664
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tambara, R. F.
A1 - Durlo Tambara, Luis Urbano
A1 - Venquiaruto, S. D.
A1 - Pereira da Costa, F. B.
T1 - Evaluation of the mechanical performance and capillary absorption of concretes with incorporation of crystallizing admixtures and subjected to damage at early ages
T1 - Avaliação do desempenho mecânico e absorção capilar de concretos com incorporação de aditivos cristalizante submetidos a danos nas primeiras idades
JF - Matéria (Rio J.)
N2 - This study assessed the self-healing phenomenon in the mechanical properties and capillary absorption of structural concretes. Two crystalline powder additives were evaluated, dosed according to the manufacturers’ recommendations. Crystalline additives increase the density of the C-S-H gel and form insoluble crystals, effectively blocking fissures. Three concrete mixes were produced: a reference mix, additive-X with 0.8%, and additive-Y with 2.0%, relative to the mass of cement. 75% of the rupture load was applied at 3- and 14-days to induce microfissures for comparison with the reference mix. Subsequently, self-healing was assessed at 28- and 76-days. The property of axial compressive strength was determined at 28-days, revealing that crystalline additives contributed to an average increase of 12% in this property. While the age of loading did not significantly impact axial compressive strength, there were significant variations among the types of additives studied, as indicated by ANOVA. Water absorption properties through capillarity were evaluated at 28- and 76-days, showing an average reduction of 42% in water absorption due to the use of crystalline additives. In conclusion, the inclusion of crystalline additives positively contributed to the self-healing of the studied concretes, suggesting a partial recovery of microfissures.
N2 - Esta pesquisa avaliou o fenômeno de autocicatrização nas propriedades mecânicas e absorção capilar de concretos estruturais. Foram avaliados dois aditivos cristalizantes em pó, dosados de acordo com o teor recomendado pelos fabricantes. Aditivos cristalizantes aumentam a densidade do gel C-S-H e formam cristais insolúveis, bloqueando fissuras. Três traços de concreto foram produzidos: referência, aditivo-X com 0,8% e aditivo-Y com 2,0% em relação a massa do cimento. Aplicou-se 75% da carga de ruptura aos 3- e 14-dias para gerar microfissuras e comparar com a referência. Posteriormente, a autocicatrização foi avaliada aos 28- e 76-dias. A propriedade de resistência à compressão axial foi determinada aos 28-dias, revelando que os aditivos cristalizantes contribuíram para um aumento médio de 12% desta propriedade. A idade do carregamento dos concretos não apresentou um impacto significativo na resistência à compressão axial, mas apontou resultados significativos entre os tipos de aditivos estudados, conforme ANOVA. As propriedades de absorção de água por capilaridade foram avaliadas aos 28- e 76-dias, indicando uma redução de absorção de água média de 42% devido ao uso dos aditivos cristalizantes. Em conclusão, a incorporação dos aditivos cristalizantes contribuiu de maneira positiva para a autocicatrização dos concretos estudados, indicando uma recuperação parcial das microfissuras.
KW - Self-healing
KW - Crystalline admixture
KW - Concrete
KW - Cracks
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599140
DO - https://doi.org/10.1590/1517-7076-RMAT-2023-0355
SN - 1517-7076
VL - 29
IS - 1
SP - 1
EP - 20
CY - Rio de Janeiro
AN - OPUS4-59914
LA - por
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jovičević-Klug, Matic
A1 - Souza Filho, Isnaldi R.
A1 - Springer, Hauke
A1 - Adam, Christian
A1 - Raabe, Dierk
T1 - Green steel from red mud through climate-neutral hydrogen plasma reduction
JF - Nature
N2 - AbstractRed mud is the waste of bauxite refinement into alumina, the feedstock for aluminium production1. With about 180 million tonnes produced per year1, red mud has amassed to one of the largest environmentally hazardous waste products, with the staggering amount of 4 billion tonnes accumulated on a global scale1. Here we present how this red mud can be turned into valuable and sustainable feedstock for ironmaking using fossil-free hydrogen-plasma-based reduction, thus mitigating a part of the steel-related carbon dioxide emissions by making it available for the production of several hundred million tonnes of green steel. The process proceeds through rapid liquid-state reduction, chemical partitioning, as well as density-driven and viscosity-driven separation between metal and oxides. We show the underlying chemical reactions, pH-neutralization processes and phase transformations during this surprisingly simple and fast reduction method. The approach establishes a sustainable toxic-waste treatment from aluminium production through using red mud as feedstock to mitigate greenhouse gas emissions from steelmaking.
KW - Multidisciplinary
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594424
DO - https://doi.org/10.1038/s41586-023-06901-z
SN - 0028-0836
VL - 625
IS - 7996
SP - 703
EP - 709
PB - Springer Science and Business Media LLC
AN - OPUS4-59442
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fantin, Andrea
A1 - Manzoni, Anna Maria
A1 - Springer, H.
A1 - Darvishi Kamachali, Reza
A1 - Maaß, Robert
T1 - Local lattice distortions and chemical short-range order in MoNbTaW
JF - Materials Research Letters
N2 - Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, δexp, is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO.
KW - High Entropy Alloys
KW - Short-range order
KW - Lattice distortions
KW - EXAFS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598164
DO - https://doi.org/10.1080/21663831.2024.2326014
SN - 2166-3831
VL - 12
IS - 5
SP - 346
EP - 354
PB - Taylor & Francis
AN - OPUS4-59816
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Darvishi Kamachali, Reza
A1 - Wallis, Theophilius
A1 - Ikeda, Yuki
A1 - Saikia, U.
A1 - Ahmadian, A.
A1 - Liebscher, C.
A1 - Hickel, Tilmann
A1 - Maaß, Robert
T1 - Giant segregation transition as origin of liquid metal embrittlement in the Fe-Zn system
JF - Scripta Materialia
N2 - A giant Zn segregation transition is revealed using CALPHAD-integrated density-based modeling of segregation into Fe grain boundaries (GBs). The results show that above a threshold of only a few atomic percent Zn in the alloy, a substantial amount of up to 60 at.% Zn can segregate to the GB. We found that the amount of segregation abruptly increases with decreasing temperature, while the Zn content in the alloy required for triggering the segregation transition decreases. Direct evidence of the Zn segregation transition is obtained using high-resolution scanning transmission electron microscopy. Base on the model, we trace the origin of the segregation transition back to the low cohesive energy of Zn and a miscibility gap in Fe-Zn GB, arising from the magnetic ordering effect, which is confirmed by ab-initio calculations. We also show that the massive Zn segregation resulting from the segregation transition greatly assists with liquid wetting and reduces the work of separation along the GB. The current predictions suggest that control over Zn segregation, by both alloy design and optimizing the galvanization and welding processes, may offer preventive strategies against liquid metal embrittlement.
KW - CALPHAD
KW - Microstructure Design
KW - Grain boundary engineering
KW - Steels
KW - Density-based Model
KW - Segregation Engineering
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584292
DO - https://doi.org/10.1016/j.scriptamat.2023.115758
SN - 1359-6462
SN - 1872-8456
VL - 238
SP - 1
EP - 5
PB - Elsevier
CY - Amsterdam
AN - OPUS4-58429
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kricheldorf, H.
A1 - Weidner, Steffen
A1 - Scheliga, F.
T1 - Polycondensation of poly(L-lactide) alkyl esters combined with disproportionation and symproportionation of the chain lengths
JF - Journal of Polymer Science A: Polymer Chemistry
N2 - Ring-opening polymerizations (ROPs) of l-lactide (LA) were performed with ethyl l-lactate or 11-bromoundecanol as initiators (In) and tin(II) ethyl hexanoate (SnOct2) as catalyst (Cat) using four different LA/In ratios (20/1, 40/1, 60/1, and 100/1). One series of ROPs was conducted in bulk at 120 °C, yielding PLAs with low dispersities (Ð ~ 1.2–1.4), and a second series was conducted in bulk at 160 °C, yielding higher dispersities (Ð ~ 1.3–1.9). Samples from both series were annealed for 1 or 14 days at 140 °C in the presence of SnOct2. Both polycondensation and disproportionation reactions occurred, so that all four samples tended to form the same type of molar mass distribution below 10,000 Da, regardless of their initially different number average molar masses (Mn). Both initiators gave nearly identical results. The thermodynamic control of all reversible transesterification processes favored the formation of crystallites composed of chains with a Mn around 3500–3700, corresponding to a crystal thickness of 10–13 nm.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600081
DO - https://doi.org/10.1002/pol.20240118
SN - 2642-4150
SP - 1
EP - 12
PB - Wiley
AN - OPUS4-60008
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Piesker, Benjamin
A1 - Ávila Calderón, Luis Alexander
A1 - Mohr, Gunther
A1 - Rehmer, Birgit
A1 - Agudo Jácome, Leonardo
A1 - Hilgenberg, Kai
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
T1 - Tensile and Low‐Cycle Fatigue Behavior of Laser Powder Bed Fused Inconel 718 at Room and High Temperature
JF - Advanced Engineering Materials
N2 - This study investigates the room‐ and high‐temperature (650 °C) tensile and low‐cycle‐fatigue behavior of Inconel 718 produced by laser powder bed fusion (PBF‐LB/M) with a four‐step heat treatment and compares the results to the conventional wrought material. The microstructure after heat treatment is characterized on different length scales. Compared to the wrought variant, the elastic and yield properties are comparable at both test temperatures while tensile strength, ductility, and strain hardening capacity are lower. The fatigue life of the PBF‐LB/M variant at room temperature is slightly lower than that of the wrought material, while at 650 °C, it is vice versa. The cyclic stress response for both material variants is characterized by cyclic softening, which is more pronounced at the higher test temperature. High strain amplitudes (≥0.7%) at room temperature and especially a high testing temperature result in the formation of multiple secondary cracks at the transitions of regions comprising predominantly elongated grain morphology and columns of stacked grains with ripple patterns in the PBF‐LB/M material. This observation and pronounced crack branching and deflection indicate that the cracks are controlled by sharp micromechanical gradients and local crystallite clusters.
KW - Additive manufacturing
KW - Fatigue damage
KW - Heat treatment
KW - Inconel 718
KW - Laser powder bed fusion
KW - Low-cycle fatigue
KW - Tensile strength
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599316
DO - https://doi.org/10.1002/adem.202302122
SN - 1527-2648
SP - 1
EP - 17
PB - Wiley
AN - OPUS4-59931
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
T1 - Semantic integration of diverse data in materials science: Assessing Orowan strengthening
JF - Scientific Data
N2 - AbstractThis study applies Semantic Web technologies to advance Materials Science and Engineering (MSE) through the integration of diverse datasets. Focusing on a 2000 series age-hardenable aluminum alloy, we correlate mechanical and microstructural properties derived from tensile tests and dark-field transmission electron microscopy across varied aging times. An expandable knowledge graph, constructed using the Tensile Test and Precipitate Geometry Ontologies aligned with the PMD Core Ontology, facilitates this integration. This approach adheres to FAIR principles and enables sophisticated analysis via SPARQL queries, revealing correlations consistent with the Orowan mechanism. The study highlights the potential of semantic data integration in MSE, offering a new approach for data-centric research and enhanced analytical capabilities.
KW - Semantic Interoperability
KW - Knowledge Graph
KW - Orowan Mechanism
KW - Aluminum Alloy Aging
KW - Ontology
KW - Semantic Data Integration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599780
DO - https://doi.org/10.1038/s41597-024-03169-4
VL - 11
IS - 1
SP - 1
EP - 12
PB - Springer Science and Business Media LLC
AN - OPUS4-59978
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Temgoua, Ranil C.T.
A1 - Dontsi, Fabiola T.
A1 - Lebègue, Estelle
A1 - Thobie-Gautier, Christine
A1 - Tonlé, Ignas K.
A1 - Boujtita, Mohammed
T1 - Understanding the behavior of phenylurazole-tyrosine-click electrochemical reaction using hybrid electroanalytical techniques
JF - Journal of Pharmaceutical and Biomedical Analysis
N2 - In this work, the electrochemical behavior of 4-phenylurazole (Ph-Ur) was studied and the latter was used as a molecular anchor for the electrochemical bioconjugation of tyrosine (Y). Cyclic voltammetry (CV) and controlled potential coulometry (CPC) allowed the in-situ generation of the PTAD (4-phenyl-3 H-1,2,4-triazole-3,5(4 H)-dione) species from phenylurazole on demand for tyrosine electrolabeling. The chemoselectivity of the reaction was studied with another amino acid (lysine, Lys) and no changes in Lys were observed. To evaluate the performance of tyrosine electrolabeling, coulometric analyses at controlled potentials were performed on solutions of phenylurazole and the phenylurazole-tyrosine mixture in different proportions (2:1, 1:1, and 1:2). The electrolysis of the phenylurazole-tyrosine mixture in the ratio (1:2) produced a charge of 2.07 C, very close to the theoretical value (1.93 C), with high reaction kinetics, a result obtained here for the first time. The products obtained were identified and characterized by liquid chromatography coupled to high-resolution electrospray ionization mass spectrometry (LC-HRMS and LC- HRMS2). Two products were formed from the click reactions, one of which was the majority. Another part of this work was to study the electrochemical degradation of the molecular anchor 4-phenylazole (Ph-Ur). Four stable degradation products of phenylurazole were identified (C7H9N2O, C6H8N, C6H8NO, C14H13N4O2) based on chromatographic profiles and mass spectrometry results. The charge generated during the electrolysis of phenylurazole (two-electron process) (2.85 C) is inconsistent with the theoretical or calculated charge (1.93 C), indicating that secondary/parasitic reactions occurred during the electrolysis of the latter. In conclusion, the electrochemically promoted click phenylurazole-tyrosine reactions give rise to click products with high reaction kinetics and yields in the (1:2) phenylurazole-tyrosine ratios, and the presence of side reactions is likely to affect the yield of the click phenylurazole-tyrosine reaction.
KW - Clinical Biochemistry
KW - Spectroscopy
KW - Drug Discovery
KW - Pharmaceutical Science
KW - Analytical Chemistry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599267
DO - https://doi.org/10.1016/j.jpba.2024.116147
VL - 245
SP - 1
EP - 8
PB - Elsevier BV
AN - OPUS4-59926
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Ghnatios, C.
A1 - Klawoon, Alexander
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
A1 - Robens-Radermacher, Annika
T1 - Efficient bead-on-plate weld model for parameter estimation towards effective wire arc additive manufacturing simulation
JF - Welding in the World
N2 - Despite the advances in hardware and software techniques, standard numerical methods fail in providing real-time simulations, especially for complex processes such as additive manufacturing applications. A real-time simulation enables process control through the combination of process monitoring and automated feedback, which increases the flexibility and quality of a process. Typically, before producing a whole additive manufacturing structure, a simplified experiment in the form of a beadon-plate experiment is performed to get a first insight into the process and to set parameters suitably. In this work, a reduced order model for the transient thermal problem of the bead-on-plate weld simulation is developed, allowing an efficient model calibration and control of the process. The proposed approach applies the proper generalized decomposition (PGD) method, a popular model order reduction technique, to decrease the computational effort of each model evaluation required multiple times in parameter estimation, control, and optimization. The welding torch is modeled by a moving heat source, which leads to difficulties separating space and time, a key ingredient in PGD simulations. A novel approach for separating space and time is applied and extended to 3D problems allowing the derivation of an efficient separated representation of the temperature.
The results are verified against a standard finite element model showing excellent agreement. The reduced order model is also leveraged in a Bayesian model parameter estimation setup, speeding up calibrations and ultimately leading to an optimized real-time simulation approach for welding experiment using synthetic as well as real measurement data.
KW - Proper generalized decomposition
KW - Model order reduction
KW - Hardly separable problem
KW - Additive manufacturing
KW - Model calibration
KW - Wire arc additive manufacturing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596502
DO - https://doi.org/10.1007/s40194-024-01700-0
SN - 0043-2288
SP - 1
EP - 18
PB - Springer
AN - OPUS4-59650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Strobl, Dominic
A1 - Unger, Jörg F.
A1 - Ghnatios, C.
A1 - Robens-Radermacher, Annika
T1 - PGD in thermal transient problems with a moving heat source: A sensitivity study on factors affecting accuracy and efficiency
JF - Engineering Reports
N2 - Thermal transient problems, essential for modeling applications like welding and additive metal manufacturing, are characterized by a dynamic evolution of temperature. Accurately simulating these phenomena is often computationally expensive, thus limiting their applications, for example for model parameter estimation or online process control. Model order reduction, a solution to preserve the accuracy while reducing the computation time, is explored. This article addresses challenges in developing reduced order models using the proper generalized decomposition (PGD) for transient thermal problems with a specific treatment of the moving heat source within the reduced model. Factors affecting accuracy, convergence, and computational cost, such as discretization methods (finite element and finite difference), a dimensionless formulation, the size of the heat source, and the inclusion of material parameters as additional PGD variables are examined across progressively complex examples. The results demonstrate the influence of these factors on the PGD model’s performance and emphasize the importance of their consideration when implementing such models. For thermal example, it is demonstrated that a PGD model with a finite difference discretization in time, a dimensionless representation, a mapping for a moving heat source, and a spatial domain non-separation yields the best approximation to the full order model.
KW - Additive manufacturing
KW - Mapping for unseparable load
KW - Model order reduction (MOR)
KW - Thermal transient problem
KW - Sensitivity analysis
KW - Proper generalized decomposition (PGD)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598001
DO - https://doi.org/10.1002/eng2.12887
IS - e12887
SP - 1
EP - 22
PB - John Wiley & Sons Ltd.
CY - Berlin
AN - OPUS4-59800
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feng, W.
A1 - Gemming, T.
A1 - Giebeler, L.
A1 - Qu, J.
A1 - Weinel, Kristina
A1 - Agudo Jácome, Leonardo
A1 - Büchner, B.
A1 - Gonzalez-Martinez, I.
T1 - Influence of magnetic field on electron beam-induced Coulomb explosion of gold microparticles in transmission electron microscopy
JF - Ultramicroscopy
N2 - In this work we instigated the fragmentation of Au microparticles supported on a thin amorphous carbon film by irradiating them with a gradually convergent electron beam inside the Transmission Electron Microscope. This phenomenon has been generically labeled as ‘‘electron beam-induced fragmentation’’ or EBIF and its physical origin remains contested. On the one hand, EBIF has been primarily characterized as a consequence of beam-induced heating. On the other, EBIF has been attributed to beam-induced charging eventually leading to Coulomb explosion. To test the feasibility of the charging framework for EBIF, we instigated the fragmentation of Au particles under two different experimental conditions. First, with the magnetic objective lens of the microscope operating at full capacity, i.e. background magnetic field 𝐵 = 2 T, and with the magnetic objective lens switched off (Lorenz mode), i.e. 𝐵 = 0 T. We observe that the presence or absence of the magnetic field noticeably affects the critical current density at which EBIF occurs. This strongly suggests that magnetic field effects play a crucial role in instigating EBIF on the microparticles. The dependence of the value of the critical current density on the absence or presence of an ambient magnetic field cannot be accounted for by the beam-induced heating model. Consequently, this work presents robust experimental evidence suggesting that Coulomb explosion driven by electrostatic charging is the root cause of EBIF.
KW - Electron beam-induced fragmentation
KW - Coulomb explosion
KW - X-ray diffraction
KW - Lorenz transmission electron microscopy
KW - Electron beam-induced charging
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600170
DO - https://doi.org/10.1016/j.ultramic.2024.113978
VL - 262
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-60017
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Feng, Wen
A1 - Gemming, Thomas
A1 - Giebeler, Lars
A1 - Qu, Jiang
A1 - Weinel, Kristina
A1 - Agudo Jácome, Leonardo
A1 - Büchner, Bernd
A1 - González-Martínez, Ignacio
T1 - Influence of magnetic field on electron beam-induced Coulomb explosion of gold microparticles in transmission electron microscopy
JF - Ultramicroscopy
N2 - In this work we instigated the fragmentation of Au microparticles supported on a thin amorphous carbon film by irradiating them with a gradually convergent electron beam inside the Transmission Electron Microscope. This phenomenon has been generically labeled as “electron beam-induced fragmentation” or EBIF and its physical origin remains contested. On the one hand, EBIF has been primarily characterized as a consequence of beam-induced heating. On the other, EBIF has been attributed to beam-induced charging eventually leading to Coulomb explosion. To test the feasibility of the charging framework for EBIF, we instigated the fragmentation of Au particles under two different experimental conditions. First, with the magnetic objective lens of the microscope operating at full capacity, i.e. background magnetic field B = 2 T, and with the magnetic objective lens switched off (Lorenz mode), i.e. B = 0 T. We observe that the presence or absence of the magnetic field noticeably affects the critical current density at which EBIF occurs. This strongly suggests that magnetic field effects play a crucial role in instigating EBIF on the microparticles. The dependence of the value of the critical current density on the absence or presence of an ambient magnetic field cannot be accounted for by the beam-induced heating model. Consequently, this work presents robust experimental evidence suggesting that Coulomb explosion driven by electrostatic charging is the root cause of EBIF.
KW - Electron beam-induced fragmentation
KW - Coulomb explosion
KW - X-ray diffraction
KW - Lorenz transmission electron microscopy
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600247
DO - https://doi.org/10.1016/j.ultramic.2024.113978
SN - 0304-3991
VL - 262
SP - 1
EP - 8
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-60024
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Herter, Sven-Oliver
A1 - Koch, Matthias
A1 - Haase, Hajo
T1 - First Synthesis of Ergotamine-13CD3 and Ergotaminine-13CD3 from Unlabeled Ergotamine
JF - Toxins: Detection, Control and Contamination of Mycotoxins (Volume II)
N2 - Ergot alkaloids (EAs) formed by Claviceps fungi are one of the most common food contaminants worldwide, affecting cereals such as rye, wheat, and barley. To accurately determine the level of contamination and to monitor EAs maximum levels set by the European Union, the six most common EAs (so-called priority EAs) and their corresponding epimers are quantified using high-performance liquid chromatography coupled with tandem mass spectrometry (HPLC-MS/MS). The quantification of EAs in complex food matrices without appropriate internal tandards is challenging but currently carried out in the standard method EN 7425:2021 due to their commercial unavailability. To address the need for isotopically labeled EAs, we focus on two semi-synthetic approaches for the synthesis of these reference standards. Therefore, we investigate the feasibility of the N6-demethylation of native ergotamine to yield norergotamine, which can subsequently be remethylated with an isotopically labeled methylating reagent, such as iodomethane (13CD3-I), to yield isotopically labeled ergotamine and its C8-epimer ergotaminine. Testing the isotopically labeled ergotamine/-inine against native ergotamine/-inine with HPLC coupled to high-resolution HR-MS/MS proved the structure of ergotamine-13CD3 and ergotaminine-13CD3. Thus, for the first time, we can describe their synthesis from unlabeled, native ergotamine. Furthermore, this approach is promising as a universal way to synthesize other isotopically labeled EAs.
KW - Reference Material
KW - HPLC-MS/MS
KW - Mycotoxins
KW - Standards
KW - Organic Synthesis
KW - Isotope
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600167
DO - https://doi.org/10.3390/toxins16040199
VL - 16
IS - 4
SP - 1
EP - 12
PB - MDPI
AN - OPUS4-60016
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dalgic, Mete-Sungur
A1 - Weidner, Steffen
T1 - Solvent-free sample preparation for matrix-assisted laserdesorption/ionization time-of-flight mass spectrometry ofpolymer blends
JF - Rapid Communications in Mass Spectrometry
N2 - Solvent-free sample preparation offers some advantages over solvent-based techniques, such as improved accuracy, reproducibility and sensitivity, for matrix-assisted laser desorption/ionization (MALDI) analysis. However, little or no information is available on the application of solvent-free techniques for the MALDI analysis of polymer blends. Solvent-free sample preparation by ball milling was applied with varying sample-to-matrix ratios for MALDI time-of-flight mass spectrometry analysis of various polymers, including polystyrenes, poly(methyl methacrylate)s and poly(ethylene glycol)s. The peak intensity ratios were compared with those obtained after using the conventional dried droplet sample preparation method. In addition, solvent-assisted milling was also applied to improve sample homogeneities.
Depending on the sample preparation method used, different peak intensity ratios were found, showing varying degrees of suppression of the signal intensities of higher mass polymers. Ball milling for up to 30 min was required to achieve constant intensity ratios indicating homogeneous mixtures. The use of wet-assisted grinding to improve the homogeneity of the blends was found to be disadvantageous as it caused partial degradation and mass-dependent segregation of the polymers in the vials.The results clearly show that solvent-free sample preparation must be carefully considered when applied to synthetic polymer blends, as it may cause additional problems with regard to homogeneity and stability of the blends.
KW - MALDI TOF MS
KW - Sample preparation
KW - Polymer blends
KW - Solvent-free
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598570
DO - https://doi.org/10.1002/rcm.9756
SN - 0951-4198
VL - 38
IS - 12
SP - 1
EP - 9
PB - Wiley online library
AN - OPUS4-59857
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - von Törne, Wipert Jannik
A1 - Steinhäuser, Lorin
A1 - Klyk-Seitz, Urszula-Anna
A1 - Piechotta, Christian
T1 - High-resolution mass spectrometric elucidation of electron ionization induced fragmentation pathways of methylated warfarin and selected hydroxylated species
JF - International Journal of Mass Spectrometry
N2 - The plant secondary metabolite families of coumarin and 4-hydroxy coumarin have a broad pharmacological spectrum ranging from antibacterial to anticancer properties. One prominent member of this substance class is the synthetic but naturally inspired anticoagulant drug and rodenticide warfarin (coumadin). A vast number of publications focus on the identification of warfarin and its major cytochrome P450-mediated phase I metabolites by liquid chromatography (LC) with mass spectrometry (MS) and tandem mass spectrometric (MS/MS) detection techniques. For the first time, electron ionization (EI) induced high-resolution quadrupole time-of-flight mass spectrometric (HR-qToF-MS) data of in-liner derivatized warfarin and selected hydroxylated species is provided in this study as an alternative to LC-MS/MS approaches. Furthermore, the characteristic fragments and fragmentation pathways of the analyzed methyl ethers are concluded. The obtained data of analytical standards, specific deuterated and 13C-labeled compounds prove inductive cleavage of the acyl or acetonyl side chain, methyl migration, and H-migration, along with consequential inductive cleavage as predominant fragmentation routes. Based on the HR-spectral data, commonalities and differences between the analyzed compounds and fragment groups were evaluated with future applicability in structure elucidation and spectra prediction of related compounds.
KW - High-resolution mass spectrometry
KW - Warfarin
KW - Hydroxy warfarin
KW - Fragmentation pathway
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596025
DO - https://doi.org/10.1016/j.ijms.2024.117220
SN - 1387-3806
VL - 499
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-59602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Zengchao
A1 - Winckelmann, Alexander
A1 - Vogl, Jochen
A1 - Recknagel, Sebastian
A1 - Abad Andrade, Carlos Enrique
T1 - Determination of calcium, iron, and selenium in human serum by isotope dilution analysis using nitrogen microwave inductively coupled atmospheric pressure plasma mass spectrometry (MICAP-MS)
JF - Analytical and bioanalytical chemistry
N2 - In this study, we demonstrate the applicability of nitrogen microwave inductively coupled atmospheric pressure mass spectrometry (MICAP-MS) for Ca, Fe, and Se quantification in human serum using isotope dilution (ID) analysis. The matrix tolerance of MICAP-MS in Na matrix was investigated, uncovering that high Na levels can suppress the signal intensity. This suppression is likely due to the plasma loading and the space charge effect. Moreover, 40Ca and 44Ca isotopic fractionation was noted at elevated Na concentration. Nine certified serum samples were analyzed using both external calibration and ID analysis. Overestimation of Cr, Zn, As, and Se was found in the results of external calibration, which might be resulted from C-induced polyatomic interference and signal enhancement, respectively. Further investigations performed with methanol showed a similar enhancement effect for Zn, As, and Se, potentially supporting this assumption. The mass concentrations determined with ID analysis show metrological compatibility with the reference values, indicating that MICAP-MS combined with ID analysis can be a promising method for precise Ca, Fe, and Se determination. Moreover, this combination reduces the influences of matrix effects, broadening the applicability of MICAP-MS for samples with complex matrix.
KW - Selenium
KW - Nitrogen microwave inductively coupled atmospheric pressure mass spectrometry
KW - Isotope dilution
KW - Human serum
KW - Calcium
KW - Iron
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598664
DO - https://doi.org/10.1007/s00216-024-05274-0
SN - 1618-2642
SP - 1
EP - 9
PB - Springer
CY - Berlin
AN - OPUS4-59866
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schilling, Markus
A1 - Bayerlein, Bernd
A1 - von Hartrott, Philipp
A1 - Waitelonis, Jörg
A1 - Birkholz, Henk
A1 - Portella, Pedro Dolabella
A1 - Skrotzki, Birgit
T1 - FAIR and Structured Data: A Domain Ontology Aligned with Standard‐Compliant Tensile Testing
JF - Advanced Engineering Materials
N2 - The digitalization of materials science and engineering (MSE) is currently leading to remarkable advancements in materials research, design, and optimization, fueled by computer‐driven simulations, artificial intelligence, and machine learning. While these developments promise to accelerate materials innovation, challenges in quality assurance, data interoperability, and data management have to be addressed. In response, the adoption of semantic web technologies has emerged as a powerful solution in MSE. Ontologies provide structured and machine‐actionable knowledge representations that enable data integration, harmonization, and improved research collaboration. This study focuses on the tensile test ontology (TTO), which semantically represents the mechanical tensile test method and is developed within the project Plattform MaterialDigital (PMD) in connection with the PMD Core Ontology. Based on ISO 6892‐1, the test standard‐compliant TTO offers a structured vocabulary for tensile test data, ensuring data interoperability, transparency, and reproducibility. By categorizing measurement data and metadata, it facilitates comprehensive data analysis, interpretation, and systematic search in databases. The path from developing an ontology in accordance with an associated test standard, converting selected tensile test data into the interoperable resource description framework format, up to connecting the ontology and data is presented. Such a semantic connection using a data mapping procedure leads to an enhanced ability of querying. The TTO provides a valuable resource for materials researchers and engineers, promoting data and metadata standardization and sharing. Its usage ensures the generation of finable, accessible, interoperable, and reusable data while maintaining both human and machine actionability.
KW - Data Interoperability
KW - Domain Ontology Development
KW - FAIR Data Management
KW - Knowledge Representation
KW - Tensile Test Ontology
KW - Semantic Web Technologies
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598142
DO - https://doi.org/10.1002/adem.202400138
SN - 1438-1656
SP - 1
EP - 19
PB - Wiley VHC-Verlag
AN - OPUS4-59814
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fardan, Ahmed
A1 - Fazi, Andrea
A1 - Peng, Ru Lin
A1 - Mishurova, Tatiana
A1 - Thuvander, Mattias
A1 - Bruno, Giovanni
A1 - Brodin, Håkan
A1 - Hryha, Eduard
T1 - Fine-Tuning Melt Pools and Microstructures: Taming Cracks in Powder Bed Fusion—Laser Beam of a non-weldable Ni-base Superalloy
JF - Materialia
N2 - Powder Bed Fusion – Laser Beam (PBF-LB) of high γ’ strengthened Ni-base superalloys, such as CM247LC, is of great interest for high temperature applications in gas turbines. However, PBF-LB of CM247LC is challenging due to the high cracking susceptibility during PBF-LB processing (solidification cracking) and heat treatment (strain age cracking, mostly caused by residual stresses). This study focuses on understanding the impact of process parameters on microstructure, residual stresses and solidification cracking. Laser power (P), speed (v) and hatch spacing (h) were varied while the layer thickness (t) was fixed. The melt pool size and shape were found to be key factors in minimizing solidification cracking. Narrower and shallower melt pools, achieved using a low line energy density (LED = P/v ≤ 0.1 J/mm), gave low crack densities (0.7 mm/mm2). A tight hatch spacing (h = 0.03 mm) resulted in reduced lack of fusion porosity. Electron backscatter diffraction investigations revealed that parameters giving finer microstructure with 〈100〉crystallographic texture had low crack densities provided they were processed with a low LED. Atom probe tomography elucidated early stages of spinodal decomposition in the as-built condition, where Cr and Al cluster separately. The extent of spinodal decomposition was found to be affected by the LED and the hatch spacing. Samples with low LED and small hatch spacing showed higher degrees of spinodal decomposition. X-ray diffraction residual stress investigations revealed that the residual stress is proportional to the volumetric energy density (VED = P/(v. h. t)). Although low residual stresses can be achieved by using low VED, there is a high risk of lack of fusion. Hence, other parameters such as modified scan strategy, build plate pre-heating and pulsed laser mode, must be further explored to minimize the residual stresses to reduce the strain age cracking susceptibility.
KW - Additive manufacturing
KW - X-ray CT
KW - Non-weldable superalloy
KW - Solidification cracking
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597340
DO - https://doi.org/10.1016/j.mtla.2024.102059
SN - 2589-1529
VL - 34
IS - 102059
SP - 1
EP - 16
PB - Elsevier B.V.
AN - OPUS4-59734
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hoffmann, Moritz
A1 - Stawarczyk, Bogna
A1 - Günster, Jens
A1 - Zocca, Andrea
T1 - Influence of additives and binder on the physical properties of dental silicate glass-ceramic feedstock for additive manufacturing
JF - Journal of the Mechanical Behavior of Biomedical Materials
N2 - Objectives
The aim of the study was to investigate the impact of organic additives (binder, plasticizer, and the cross-linking ink) in the formulation of water-based feedstocks on the properties of a dental feldspathic glass-ceramic material developed for the slurry-based additive manufacturing technology “LSD-print.”
Material and methods
Three water-based feldspathic feedstocks were produced to study the effects of polyvinyl alcohol (AC1) and poly (sodium 4-styrenesulfonate) (AC2) as binder systems. A feedstock without organic additives was tested as the control group (CG). Disc-shaped (n = 15) and bar (n = 7) specimens were slip-cast and characterized in the green and fired states. In the green state, density and flexural strength were measured. In the fired state, density, shrinkage, flexural strength (FS), Weibull modulus, fracture toughness (KIC), Martens parameters, and microstructure were analyzed. Disc-shaped and bar specimens were also cut from commercially available CAD/CAM blocks and used as a target reference (TR) for the fired state.
Results
In the green state, CG showed the highest bulk density but the lowest FS, while the highest FS in the green state was achieved with the addition of a cross-linking ink. After firing, no significant differences in density and a similar microstructure were observed for all slip-cast groups, indicating that almost complete densification could be achieved. The CAD/CAM specimens showed the highest mean FS, Weibull modulus, and KIC, with significant differences between some of the slip-cast groups.
Significance
These results suggest that the investigated feedstocks are promising candidates for the slurry-based additive manufacturing of restorations meeting the class 1a requirements according to DIN EN ISO 6871:2019–01.
KW - Firing
KW - 3D-printing
KW - Silicate glass-ceramics
KW - Debinding
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600516
DO - https://doi.org/10.1016/j.jmbbm.2024.106563
SN - 1751-6161
VL - 155
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-60051
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fareed, Adnan
A1 - Rosalie, Julian M.
A1 - Kar, Satyakam
A1 - Fähler, Sebastian
A1 - Maaß, Robert
T1 - Small-scale functional fatigue of a Ni-Mn-Ga Heusler alloy
JF - Acta Materialia
N2 - Functional fatigue of shape-memory alloys is a considerable threat to the reliable service of actuation devices. Here, we demonstrate the essentially degradation-free cyclic phase-transformation behavior of Ni-Mn-Ga microcrystals up to one million stress-driven superelastic cycles. Cyclic dissipation amounts to about 1/5 of the bulk counterpart and remains unaffected during cycling, even after the introduction of dislocation structures via plastic straining. Plastic yielding and the transformation stress largely exceed the known bulk values. However, the transformation-stress is found to depend on plastic pre-straining, which suggests that the size-affected transformation stress is sensitive to the initial defect structure and that it can be tuned by a targeted introduction of dislocations. These findings demonstrate the high suitability of Ni-Mn-Ga as a robust shape-memory alloy in small-scale functional device engineering.
KW - Superelasticity
KW - Shape-memory alloys
KW - Functional fatigue
KW - Ni-Mn-Ga
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600695
DO - https://doi.org/10.1016/j.actamat.2024.119988
VL - 274
SP - 1
EP - 10
PB - Elsevier B.V.
AN - OPUS4-60069
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - You, Yi
A1 - Danischewski, Julia
A1 - Molnar, Brian
A1 - Riedel, Jens
A1 - Shelley, Jacob
T1 - Manipulation of Gaseous Ions with Acoustic Fields at Atmospheric Pressure
JF - Journal of the American Chemical Society
N2 - The ability to controllably move gaseous ions is an essential aspect of ion-based spectrometry (e.g., mass spectrometry and ion mobility spectrometry) as well as materials processing. At higher pressures, ion motion is largely governed by diffusion and multiple collisions with neutral gas molecules. Thus, high-pressure ion optics based on electrostatics require large fields, radio frequency drives, complicated geometries, and/or partially transmissive grids that become contaminated. Here, we demonstrate that low-power standing acoustic waves can be used to guide, block, focus, and separate beams of ions akin to electrostatic ion optics. Ions preferentially travel through the static-pressure regions (“nodes”) while neutral gas does not appear to be impacted by the acoustic field structure and continues along a straight trajectory. This acoustic ion manipulation (AIM) approach has broad implications for ion manipulation techniques at high pressure, while expanding our fundamental understanding of the behavior of ions in gases.
KW - Ion mobility spectrometry
KW - Acoustic
KW - Mass spectrometry
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600704
DO - https://doi.org/10.1021/jacs.4c01224
SP - 1
EP - 6
PB - ACS Publications
AN - OPUS4-60070
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Maulas, Kryzzyl M.
A1 - Paredes, Charla S.
A1 - Tabelin, Carlito Baltazar
A1 - Jose, Mark Anthony
A1 - Opiso, Einstine M.
A1 - Arima, Takahiko
A1 - Park, Ilhwan
A1 - Mufalo, Walubita
A1 - Ito, Mayumi
A1 - Igarashi, Toshifumi
A1 - Phengsaart, Theerayut
A1 - Villas, Edrhea
A1 - Dagondon, Sheila L.
A1 - Metillo, Ephrime B.
A1 - Uy, Mylene M.
A1 - Manua, Al James A.
A1 - Villacorte-Tabelin, Mylah
T1 - Isolation and Characterization of Indigenous Ureolytic Bacteria from Mindanao, Philippines: Prospects for Microbially Induced Carbonate Precipitation (MICP)
JF - Minerals
N2 - Microbially induced carbonate precipitation (MICP), a widespread phenomenon in nature, is gaining attention as a low-carbon alternative to ordinary Portland cement (OPC) in geotechnical engineering and the construction industry for sustainable development. In the Philippines, however, very few works have been conducted to isolate and identify indigenous, urease-producing (ureolytic) bacteria suitable for MICP. In this study, we isolated seven, ureolytic and potentially useful bacteria for MICP from marine sediments in Iligan City. DNA barcoding using 16s rDNA identified six of them as Pseudomonas stutzeri, Pseudomonas pseudoalcaligenes, Bacillus paralicheniformis, Bacillus altitudinis, Bacillus aryabhattai, and Stutzerimonas stutzeri but the seventh was not identified since it was a bacterial consortium. Bio-cementation assay experiments showed negligible precipitation in the control (without bacteria) at pH 7, 8, and 9. However, precipitates were formed in all seven bacterial isolates, especially between pH 7 and 8 (0.7–4 g). Among the six identified bacterial species, more extensive precipitation (2.3–4 g) and higher final pH were observed in S. stutzeri, and B. aryabhattai, which indicate better urease production and decomposition, higher CO2 generation, and more favorable CaCO3 formation. Characterization of the precipitates by scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM-EDS) and attenuated total reflectance Fourier transform spectroscopy (ATR-FTIR) confirmed the formation of three carbonate minerals: calcite, aragonite, and vaterite. Based on these results, all six identified indigenous, ureolytic bacterial species from Iligan City are suitable for MICP provided that the pH is controlled between 7 and 8. To the best of our knowledge, this is the first report of the urease-producing ability and potential for MICP of P. stutzeri, P. pseudoalcaligenes, S. stutzeri, and B. aryabhattai.
KW - Calcium carbonate
KW - Microbially induced carbonate precipitation (MICP)
KW - Ureolytic bacteria
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600888
DO - https://doi.org/10.3390/min14040339
VL - 14
IS - 4
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-60088
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hartwig, Philipp
A1 - Bakir, Nasim
A1 - Gumenyuk, Andrey
A1 - Scheunemann, Lisa
A1 - Schröder, Jörg
A1 - Rethmeier, Michael
T1 - A Physically Motivated Heat Source Model for Laser Beam Welding
JF - Metals
N2 - In this contribution, we present a physically motivated heat source model for the numerical modeling of laser beam welding processes. Since the calibration of existing heat source models, such as the conic or Goldak model, is difficult, the representation of the heat source using so-called Lamé curves has been established, relying on prior Computational Fluid Dynamics (CFD) simulations.
Lamé curves, which describe the melting isotherm, are used in a subsequent finite-element (FE) simulation to define a moving Dirichlet boundary condition, which prescribes a constant temperature in the melt pool. As an alternative to this approach, we developed a physically motivated heat source model, which prescribes the heat input as a body load directly. The new model also relies on prior CFD simulations to identify the melting isotherm. We demonstrate numerical results of the new heat source model on boundary-value problems from the field of laser beam welding and compare it with the prior CFD simulation and the results of the Lamé curve model and experimental data.
KW - Welding simulation
KW - Heat source models
KW - Laser beam welding
KW - Thermal analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600899
DO - https://doi.org/10.3390/met14040430
VL - 14
IS - 4
SP - 1
EP - 26
PB - MDPI
CY - Basel
AN - OPUS4-60089
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schlögl, Johanna
A1 - Goldammer, Ole
A1 - Bader, Julia
A1 - Emmerling, Franziska
A1 - Riedel, Sebastian
T1 - Introducing AFS ([Al(SO3F)3]x) – a thermally stable, readily available, and catalytically active solid Lewis superacid
JF - Chemical Science
N2 - This paper introduces the thermally stable, solid Lewis superacid aluminium tris(fluorosulfate) (AFS), that is easy-to-synthesize from commercially available starting materials. Its applicability, e.g. in catalytic C–F bond activations, is shown.
KW - Lewis Acid
KW - C-F activation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601001
DO - https://doi.org/10.1039/D4SC01753F
SN - 2041-6520
SP - 1
EP - 7
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-60100
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fiedler, Saskia
A1 - Frenzel, Florian
A1 - Würth, Christian
A1 - Tavernaro, Isabella
A1 - Grüne, M.
A1 - Schweizer, S.
A1 - Engel, A.
A1 - Resch-Genger, Ute
T1 - Interlaboratory Comparison on Absolute Photoluminescence Quantum Yield Measurements of Solid Light Converting Phosphors with Three Commercial Integrating Sphere Setups
JF - American Chemical Society
N2 - Scattering luminescent materials dispersed in liquid and solid matrices and luminescent powders are increasingly relevant for fundamental research and industry. Examples are luminescent nano- and microparticles and phosphors of different compositions in various matrices or incorporated into ceramics with applications in energy conversion, solid-state lighting, medical diagnostics, and security barcoding. The key parameter to characterize the performance of these materials is the photoluminescence/fluorescence quantum yield (Φf), i.e., the number of emitted photons per number of absorbed photons. To identify and quantify the sources of uncertainty of absolute measurements of Φf of scattering samples, the first interlaboratory comparison (ILC) of three laboratories from academia and industry was performed by following identical measurement protocols. Thereby, two types ofcommercial stand-alone integrating sphere setups with different illumination and detection geometries were utilized for measuring the Φf of transparent and scattering dye solutions and solid phosphors, namely, YAG:Ce optoceramics of varying surface roughness, used as converter materials for blue light emitting diodes. Special emphasis was dedicated to the influence of the measurement geometry, the optical properties of the blank utilized to determine the number of photons of the incident excitation light absorbed by the sample, and the sample-specific surface roughness. While the Φf values of the liquid samples matched between instruments, Φf measurements of the optoceramics with different blanks revealed substantial differences. The ILC results underline the importance of the measurement geometry, sample position, and blank for reliable Φf data of scattering the YAG:Ce optoceramics, with the blank’s optical properties accounting for uncertainties exceeding 20%.
KW - Nano
KW - Fluorescence
KW - Reference material
KW - Luminescence
KW - Quantitative spectroscopy
KW - Particle
KW - Quantum yield
KW - Quality assurance
KW - Phosphor
KW - Converter material
KW - Lifetime
KW - Interlaboratory comparison
KW - Method
KW - Uncertainty
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-600945
DO - https://doi.org/10.1021/acs.analchem.4c00372
SN - 0003-2700
SP - 6730
EP - 6737
PB - ACS Publications
AN - OPUS4-60094
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Camplese, Davide
A1 - Scarponi, Giordano Emrys
A1 - Chianese, Carmela
A1 - Hajhariri, Aliasghar
A1 - Eberwein, Robert
A1 - Otremba, Frank
A1 - Cozzani, Valerio
T1 - Modeling the performance of multilayer insulation in cryogenic tanks undergoing external fire scenarios
JF - Process Safety and Environmental Protection
N2 - Multilayer Insulation (MLI) is frequently used in vacuum conditions for the thermal insulation of cryogenic storage tanks. The severe consequences of the degradation of such materials in engulfing fire scenarios were recently evidenced by several large-scale experimental tests. In the present study, an innovative modelling approach was developed to assess the performance of heat transfer in polyester-based MLI materials for cryogenic applications under fire conditions. A specific layer-by-layer approach was integrated with an apparent kinetic thermal degradation model based on thermogravimetric analysis results. The modeling results provided a realistic simulation of the experimental data obtained by High-Temperature Thermal Vacuum Chamber tests reproducing fire exposure conditions. The model was then applied to assess the behavior of MLI systems for liquid hydrogen tanks in realistic fire scenarios. The results show that in intense fire scenarios degradation occurs rapidly, compromising the thermal insulation performances of the system within a few minutes.
KW - Multilayer Insulation
KW - Cryogenic Vessels
KW - Liquefied Hydrogen
KW - Liquefied Natural Gas
KW - Safety
KW - Fire
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599418
DO - https://doi.org/10.1016/j.psep.2024.04.061
SN - 0957-5820
VL - 186
SP - 1169
EP - 1182
PB - Elsevier B.V.
AN - OPUS4-59941
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dittmar, Stefan
A1 - Ruhl, Aki S.
A1 - Altmann, Korinna
A1 - Jekel, Martin
T1 - Settling Velocities of Small Microplastic Fragments and Fibers
JF - Environmental Science & Technology
N2 - There is only sparse empirical data on the settling velocity of small, non-buoyant microplastics thus far, although it is an important parameter governing their vertical transport within aquatic environments. This study reports the settling velocities of 4031 exemplary microplastic particles. Focusing on the environmentally most prevalent particle shapes, irregular microplastic fragments of four different polymer types (9–289 µm) as well as five discrete length fractions (50–600 µm) of common nylon and polyester fibers were investigated, respectively. All settling experiments were carried out in quiescent water using a specialized optical imaging setup. The method has been previously validated in order to minimize disruptive factors, e.g. thermal convection or particle interactions, and thus enable the precise measurements of the velocities of individual microplastic particles (0.003–9.094 mm/s). Based on the obtained data, ten existing models for predicting a particle’s terminal settling velocity were assessed. It is concluded that models, which were specifically deduced from empirical data on larger microplastics, fail to provide accurate predictions for small microplastics. Instead, a different approach is highlighted as a viable option for computing settling velocities across the microplastics continuum in terms of size, density and shape.
KW - Microplastics
KW - Microplastic fibers
KW - Settling velocity
KW - Sinking velocity
KW - Sedimentation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597455
DO - https://doi.org/10.1021/acs.est.3c09602
SN - 0013-936X
VL - 58
IS - 14
SP - 6359
EP - 6369
PB - American Chemical Society (ACS)
AN - OPUS4-59745
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sieg, Holger
A1 - Schaar, Caroline
A1 - Fouquet, Nicole
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Braeuning, Albert
T1 - Particulate iron oxide food colorants (E 172) during artificial digestion and their uptake and impact on intestinal cells
JF - Toxicology in Vitro
N2 - Iron oxide of various structures is frequently used as food colorant (E 172). The spectrum of colors ranges from yellow over orange, red, and brown to black, depending on the chemical structure of the material. E 172 is mostly sold as solid powder. Recent studies have demonstrated the presence of nanoscaled particles in E 172 samples, often to a very high extent. This makes it necessary to investigate the fate of these particles after oral uptake. In this study, 7 differently structured commercially available E 172 food colorants (2 x Yellow FeO(OH), 2 x Red Fe2O3, 1 x Orange Fe2O3 + FeO(OH) and 2 x Black Fe3O4) were investigated for particle dissolution, ion release, cellular uptake, crossing of the intestinal barrier and toxicological impact on intestinal cells. Dissolution was analyzed in water, cell culture medium and artificial digestion fluids. Small-angle X-ray scattering (SAXS) was employed for determination of the specific surface area of the colorants in the digestion fluids. Cellular uptake, transport and toxicological effects were studied using human differentiated Caco-2 cells as an in vitro model of the intestinal barrier. For all materials, a strong interaction with the intestinal cells was observed, albeit there was only a limited dissolution, and no toxic in vitro effects on human cells were recorded.
KW - Toxicology
KW - Nanoparticles
KW - Small-angle X-ray scattering
KW - SAXS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593935
DO - https://doi.org/10.1016/j.tiv.2024.105772
VL - 96
SP - 1
EP - 12
PB - Elsevier BV
AN - OPUS4-59393
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heyn, A.
A1 - Meist, M.
A1 - Michael, O.
A1 - Babutzka, M.
A1 - Valet, Svenja
A1 - Ebell, Gino
T1 - Electrochemical characterization of surfaces of galvanized steels under different exposure conditions using gel electrolytes
JF - Materials and Corrosion
N2 - The corrosion behavior of galvanized steels and zinc components under atmospheric exposure depends mostly on the corrosion product‐based cover layer formation under the prevailing conditions. The use of agar‐based gel electrolytes makes it possible to use electrochemical methods to obtain a characteristic value from these cover layers that describe their current and future protective capacity. It is shown here that different states of galvanized steel can be distinguished very well under laboratory conditions and that this method is also suitable for use under practical conditions. Based on the characteristic values and assuming future time of wetness, it is very easy to draw up a forecast for the future corrosion rate, which provides plausible values.
KW - Materials Chemistry
KW - Metals and Alloys
KW - Surfaces, Coatings and Films
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - Environmental Chemistry
KW - Corrosion
KW - Znc
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599234
DO - https://doi.org/10.1002/maco.202414389
SP - 1
EP - 16
PB - Wiley VHC-Verlag
AN - OPUS4-59923
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Maxi B.
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Loeschner, Katrin
A1 - Givelet, Lucas
A1 - Fahrenson, Christoph
A1 - Braeuning, Albert
A1 - Sieg, Holger
T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics
JF - Food and Chemical Toxicology
N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles.
KW - Toxicology
KW - General Medicine
KW - Food Science
KW - Nanoplastics
KW - Nanoparticle
KW - Dynamic Light Scattering
KW - DLS
PY - 2024
DO - https://doi.org/10.1016/j.fct.2023.114423
VL - 184
SP - 1
EP - 16
PB - Elsevier
AN - OPUS4-59298
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Gluth, Gregor
A1 - Mundra, Shishir
A1 - Henning, Ricky
T1 - Chloride binding by layered double hydroxides (LDH/AFm phases) and alkali-activated slag pastes: an experimental study by RILEM TC 283-CAM
JF - Materials and Structures
N2 - Chloride binding by the hydrate phases of cementitious materials influences the rate of chloride ingress into these materials and, thus, the time at which chloride reaches the steel reinforcement in concrete structures. Chloride binding isotherms of individual hydrate phases would be required to model chloride ingress but are only scarcely available and partly conflicting. The present study by RILEM TC 283-CAM ‘Chloride transport in alkali-activated materials’ significantly extends the available database and resolves some of the apparent contradictions by determining the chloride binding isotherms of layered double hydroxides (LDH), including AFm phases (monosulfate, strätlingite, hydrotalcite, and meixnerite), and of alkali-activated slags (AAS) produced with four different activators (Na2SiO3, Na2O·1.87SiO2, Na2CO3, and Na2SO4), in NaOH/NaCl solutions at various liquid/solid ratios. Selected solids after chloride binding were analysed by X-ray diffraction, and thermodynamic modelling was applied to simulate the phase changes occurring during chloride binding by the AFm phases. The results of the present study show that the chloride binding isotherms of LDH/AFm phases depend strongly on the liquid/solid ratio during the experiments. This is attributed to kinetic restrictions, which are, however, currently poorly understood. Chloride binding by AAS pastes is only moderately influenced by the employed activator. A steep increase of the chloride binding by AAS occurs at free chloride concentrations above approx. 1.0 M, which is possibly related to chloride binding by the C–(N–)A–S–H gel in the AAS.
KW - Chloride binding
KW - Sorption isotherm
KW - Layered double hydroxide
KW - AFm phase
KW - Alkali-activated materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599370
DO - https://doi.org/10.1617/s11527-024-02311-3
SN - 1359-5997
SN - 1871-6873
VL - 57
IS - 4
SP - 1
EP - 17
PB - Springer Nature
AN - OPUS4-59937
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kindrachuk, Vitaliy
A1 - Darvishi Kamachali, Reza
T1 - Mean-field modeling and phase-field simulation of grain growth under directional driving forces
JF - Materialia
N2 - Directional grain growth is a common phenomenon in the synthetic and natural evolution of various polycrystals. It occurs in the presence of an external driving force, such as a temperature gradient, along which grains show a preferred, yet competitive, growth. Novel additive manufacturing processes, with intense, localized energy deposition, are prominent examples of when directional grain growth can occur, beneath the melting pool. In this work, we derive a phenomenological mean-field model and perform 3D phase-field simulations to investigate the directional grain growth and its underlying physical mechanisms. The effect of the intensity of driving force is simulated and systematically analyzed at the evolving growth front as well as various cross-sections perpendicular to the direction of the driving force. We found that although the directional growth significantly deviates from normal grain growth, it is still governed by a power law relation α tⁿ with an exponent n ~ 0.6–0.7. The exponent n exhibits a nontrivial dependence on the magnitude of the directional driving force, such that the lowest growth exponent is observed for intermediate driving forces. We elaborate that this can originate from the fact that the forces at grain boundary junctions evolve out of balance under the influence of the directional driving force. With increasing the driving forces, the growth exponent asymptotically approaches a value of n ≈ 0.63, imposed by the largest possible grain aspect ratio for given grain boundary energies. The current combined mean-field and phase-field framework pave the way for future exploration in broader contexts such as the evolution of complex additively manufactured microstructures.
KW - Additive manufacturing
KW - Phase-field simulation
KW - Grain growth
KW - Mean-field modelling
KW - Directional grain growth
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593210
DO - https://doi.org/10.1016/j.mtla.2023.101989
SN - 2589-1529
VL - 33
SP - 1
EP - 10
PB - Elsevier
AN - OPUS4-59321
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Paul, Maxi B.
A1 - Böhmert, Linda
A1 - Thünemann, Andreas
A1 - Loeschner, Katrin
A1 - Givelet, Lucas
A1 - Fahrenson, Christoph
A1 - Braeuning, Albert
A1 - Sieg, Holger
T1 - Influence of artificial digestion on characteristics and intestinal cellular effects of micro-, submicro- and nanoplastics
JF - Food and Chemical Toxicology
N2 - The production of plastics is rising since they have been invented. Micro, submicro- and nanoplastics are produced intentionally or generated by environmental processes, and constitute ubiquitous contaminants which are ingested orally by consumers. Reported health concerns include intestinal translocation, inflammatory response, oxidative stress and cytotoxicity. Every digestive milieu in the gastrointestinal tract does have an influence on the properties of particles and can cause changes in their effect on biological systems. In this study, we subjected plastic particles of different materials (polylactic acid, polymethylmethacrylate, melamine formaldehyde) and sizes (micro- to nano-range) to a complex artificial digestion model consisting of three intestinal fluid simulants (saliva, gastric and intestinal juice). We monitored the impact of the digestion process on the particles by performing Dynamic Light Scattering, Scanning Electron Microscopy and Asymmetric Flow Field-Flow Fractionation. An in vitro model of the intestinal epithelial barrier was used to monitor cellular effects and translocation behavior of (un)digested particles. In conclusion, artificial digestion decreased cellular interaction and slightly increased transport of all particles across the intestinal barrier. The interaction with organic matter resulted in clear differences in the agglomeration behavior. Moreover, we provide evidence for polymer-, size- and surface-dependent cellular effects of the test particles.
KW - Toxicology
KW - Nanoparticles
KW - Dynamic Light Scattering
KW - Nanoplastics
KW - Microplastics
KW - Reference Method
KW - Reference Material
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593947
DO - https://doi.org/10.1016/j.fct.2023.114423
VL - 184
SP - 1
EP - 16
PB - Elsevier BV
AN - OPUS4-59394
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Geißler, Daniel
A1 - Wegner, Karl David
A1 - Fischer, C.
A1 - Resch-Genger, Ute
T1 - Exploring Simple Particle-Based Signal Amplification Strategies in a Heterogeneous Sandwich Immunoassay with Optical Detection
JF - Analytical Chemistry
N2 - Heterogeneous sandwich immunoassays are widely used for biomarker detection in bioanalysis and medical diagnostics. The high analyte sensitivity of the current “gold standard” enzyme-linked immunosorbent assay (ELISA) originates from the signal-generating enzymatic amplification step, yielding a high number of optically detectable reporter molecules. For future point-of-care testing (POCT) and point-of-need applications, there is an increasing interest in more simple detection strategies that circumvent time-consuming and temperature-dependent enzymatic reactions. A common concept to aim for detection limits comparable to those of enzymatic amplification reactions is the usage of polymer nanoparticles (NP) stained with a large number of chromophores. We explored different simple NP-based signal amplification strategies for heterogeneous sandwich immunoassays
that rely on an extraction-triggered release step of different types of optically detectable reporters. Therefore, streptavidinfunctionalized polystyrene particles (PSP) are utilized as carriers for (i) the fluorescent dye coumarin 153 (C153) and (ii) hemin (hem) molecules catalyzing the luminol reaction enabling chemiluminescence (CL) detection. Additionally, (iii) NP labeling with hemin-based microperoxidase MP11 was assessed. For each amplification approach, the PSP was first systematically optimized regarding size, loading concentration, and surface chemistry. Then, for an immunoassay for the inflammation marker C- eactive protein (CRP), the analyte sensitivity achievable with optimized PSP
ystems was compared with the established ELISA concept for photometric and CL detection. Careful optimization led to a limit of detection (LOD) of 0.1 ng/mL for MP11-labeled PSP and CL detection, performing similarly well to a photometric ELISA (0.13 ng/mL), which demonstrates the huge potential of our novel assay concept.
KW - Nanoparticle
KW - Fluorescence
KW - Immunoassay
KW - Quality assurance
KW - Antibody
KW - Polymer
KW - Dye
KW - Signal enhancement
KW - CRP
KW - Biosensing
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597853
DO - https://doi.org/10.1021/acs.analchem.3c03691
SN - 1520-6882
VL - 96
IS - 13
SP - 5078
EP - 5085
PB - American Chemical Society
CY - Columbus, Ohio
AN - OPUS4-59785
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wegner, Karl David
A1 - Resch-Genger, Ute
T1 - The 2023 Nobel Prize in Chemistry: Quantum dots
JF - Analytical and Bioanalytical Chemistry
N2 - The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery.
KW - Quantum dots
KW - Semiconductor nanocrystals
KW - Luminescence
KW - Quantitative spectroscopy
KW - Quantum yield
KW - Advanced nanomaterials
KW - Quality assurance
KW - Energy transfer
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597843
DO - https://doi.org/10.1007/s00216-024-05225-9
VL - 2024
SP - 1
EP - 11
PB - Springer
CY - Cham
AN - OPUS4-59784
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Silvestroni, L.
A1 - Kupsch, Andreas
A1 - Müller, B. R.
A1 - Ulbricht, Alexander
A1 - Wieder, Frank
A1 - Fritsch, Tobias
A1 - Sciti, D.
A1 - Bruno, Giovanni
T1 - Determination of short carbon fiber orientation in zirconium diboride ceramic matrix composites
JF - Journal of the European Ceramic Society
N2 - In fiber-reinforced components, the fiber alignment and orientation have paramount influence on the thermomechanical properties of the resulting composite, for both short and continuous fiber. Here we present the case of an ultra-refractory matrix intended for extreme environment applications, ZrB2, reinforced with 20 vol% and 50 vol% short carbon fibers. In both cases, fibers tend to align perpendicular to the uniaxial pressure applied during shaping and sintering of a pellet, although the fiber tilt across the pellet thickness is difficult to determine. Moreover, for high volume fractions of reinforcement, the spatial distribution of the fibers is heterogeneous and tends to have domains of preferential orientations. We compare the information on the fiber distribution as collected by scanning electron microscopy images, X-ray computed tomography and synchrotron X-ray refraction radiography (SXRR). The three techniques prove to be complementary. Importantly, we demonstrate that SXRR yields the most statistically significant information due to the largest field of view, yet with a sensitivity down to the nanometer, and that can be successfully applied also to heavy matrix materials, such as zirconium boride.
KW - Ceramic matrix composites
KW - Synchrotron X-ray refraction radiography
KW - X-ray computed tomography
KW - Scanning electron microscopy
KW - High-temperature ceramics
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597712
DO - https://doi.org/10.1016/j.jeurceramsoc.2024.02.048
SN - 0955-2219
VL - 44
IS - 8
SP - 4853
EP - 4862
PB - Elsevier Ltd.
CY - Amsterdam
AN - OPUS4-59771
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roesch, Philipp
A1 - Schinnen, Andrea
A1 - Riedel, Maren
A1 - Sommerfeld, Thomas
A1 - Sawal, G.
A1 - Bandow, N.
A1 - Vogel, Christian
A1 - Kalbe, Ute
A1 - Simon, Franz-Georg
T1 - Investigation of pH-dependent extraction methods for PFAS in (fluoropolymer-based) consumer products: A comparative study between targeted and sum parameter analysis
JF - Chemosphere
N2 - Here, we report a comparative study of different sum parameter analysis methods for the extraction of per- and polyfluoroalkyl substances (PFAS) from manufactured consumer products, which can be measured by combustion ion chromatography (CIC). Therefore, a hydrolysis-based extraction method was further developed, which accounts for the addition of hydrolyzable covalently bound polyfluoroalkylated side-chain polymers (SFPs) to the extractable organic fluorine portion of the mass balance proposed as "hydrolyzable organically bound fluorine" (HOF). To test this hypothesis, the method was applied to 39 different consumer products containing fluoropolymers or monomeric PFAS taken from four different categories: outdoor textiles, paper packaging, carpeting, and permanent baking sheets. We also evaluated the method's efficiency by extracting four synthesized fluorotelomer polyacrylate reference compounds. The total fluorine (TF) and extractable organically bound fluorine (EOF) values were measured through CIC using established protocols. The TF values ranged from sub-ppb to %-levels, depending on the compound class. All samples showed results for hydrolyzed organofluorine (HOF) between 0.03 and 76.3 μg/g, while most EOF values were lower (100 μg/L (240 nM).
KW - Perfluorooctanoic Acid (PFOA)
KW - Cyclometalated iridium (III) complexes
KW - Luminescent lifetime
KW - Optically active surfaces
KW - ToF-SIMS
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594535
UR - https://pubs.acs.org/doi/10.1021/acs.analchem.3c04289
DO - https://doi.org/10.1021/acs.analchem.3c04289
VL - 96
IS - 4
SP - 1565
EP - 1575
PB - American Chemical Society (ACS)
AN - OPUS4-59453
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schuberth, Jens
A1 - Ebert, Thomas
A1 - Schlegel, Moritz-Caspar
A1 - Rödig, Lisa
A1 - Jepsen, Dirk
A1 - Memelink, Robin
A1 - Hauschke, Fynn
T1 - The Front-Runner Approach - Facilitating Progressive Product Policy by Using Information from EU Product Databases
JF - Energies
N2 - The European Commission has recently announced two guiding principles for EU product policy: First, product policy shall ensure that the performance of front-runner products in terms of sustainability becomes the norm, and second, the effectiveness of the current Ecodesign legislative framework is going to be significantly improved. Within this paper, already existing front-runner approaches and recent and ongoing product policy-making processes were reviewed. Based on the results, an EU front-runner approach is outlined. The presented approach (i) refers to performance levels of the best products already available on the market, (ii) aggregates information in existing databases, and (iii) works semi-automated. Together, all three attributes have a high potential to facilitate and accelerate the specification of appropriate minimum requirements for products at the EU level. This way, EU policymakers can deliver on the core objectives of the Ecodesign legislative framework much better. The basic mechanism and its legal entrenchment of the approach are illustrated for the energy efficiency of energy-related products. In addition, the Front-Runner Approach can be applied to any product group in the scope of the upcoming Ecodesign for Sustainable Products Regulation and to a wide range of product-related minimum requirements, such as durability, reparability, or recycled content. The study’s objective is to suggest a tailor-made and dynamic approach to keep the EU product legislation up to date using innovative technology based on the investigation of current regulations and identify the gap. Experiences from three international case studies suggest that a front-runner approach to setting energy-performance standards can drive innovation and reduce energy consumption via promoting energy-efficient products; transparency about available products is one of the key factors and can be established by a database. The EU front-runner approach comprises extending the existing energy label database (or making use of the digital product passport) and introducing a legislative procedure that triggers changes in the energy efficiency requirements in the specific EU regulations if the database shows that a certain threshold value is reached. Challenges such as limited EU staff capacities and opportunities such as increased dynamic are discussed.
KW - Ecodesign
KW - ESPR
KW - Energy labelling
KW - EPREL
KW - Policy making
KW - Front-runner
KW - Material efficiency
KW - Resource efficiency
KW - Energy efficiency
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595132
DO - https://doi.org/10.3390/en17020504
VL - 17
IS - 2
SP - 1
EP - 11
PB - MDPI
AN - OPUS4-59513
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Kricheldorf, H.
T1 - Transformation of poly(L-lactide) crystals composed of linear chains into crystals composed of cycles
JF - Polymer Chemistry
N2 - A poly(L-lactide) with a trifluoroethyl ester end group and an average degree of polymerization (DP) of 50 was synthesized by ROP of L-lactide initiated with trifluoroethanol. Small-angle X-ray scattering (SAXS) in combination with differential scanning calorimetry (DSC) measurements revealed an average crystal thickness of 13 nm, corresponding to 45 repeat units. This suggests that most crystallites were formed by extended PLA chains, and both flat surfaces were covered by CF3 groups. The crystalline PLAs were annealed at 140 or 160 °C in the presence of two catalysts: tin(II) 2-ethylhexanoate, (SnOct2) or dibutyltin bis(pentafluorophenoxide) (BuSnPhF). The chemical reactions, such as polycondensation and cyclization, proceeded in the solid state and were monitored by matrix-assisted laser desorption/ionization time-offlight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC) measurements. Under optimal conditions a large fraction of linear chains was transformed into crystallites composed of extended cycles. Additionally, MALDI TOF MS analysis of GPC fractions from samples annealed for 28 or 42 days detected chain elongation of the linear species up to a factor of 20.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
KW - Transesterification
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597250
DO - https://doi.org/10.1039/D3PY01370G
SN - 1759-9954
VL - 15
IS - 12
SP - 1173
EP - 1181
PB - Royal Society for Chemistry
AN - OPUS4-59725
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Brockmann, N.
A1 - Sicken, A.
A1 - Krüger, Jörg
T1 - Effects of laser cleaning on the condition of different silk model samples using varying wavelengths and pulse durations
JF - Heritage Science
N2 - The cleaning of aged silk fibers poses a common challenge in the conservation of textiles, since traditional cleaning techniques often yield unsatisfactory results or even harm objects. In this regard, cleaning objects with laser radiation is a promising addition to the range of available methods. Due to it being contactless, even brittle and touch-sensitive objects with disfiguring or harmful soiling could potentially be cleaned and therefore made accessible for research and presentation. Examples of treatment have sometimes shown spectacular results. Still there is some skepticism concerning the safety of this treatment for textile materials, which has been strengthened through previous 532 nm wavelength nanosecond laser cleaning studies on silk fibers. Taking these published results into account, the range of examined laser parameters has been extended in this study, from 532 nm nanosecond laser to 1064 nm nanosecond and even 800 nm femtosecond laser, reevaluating the effect of this treatment on the fibers. The physicochemical processes taking place on the silk fibers when cleaning with lasers are complex and still not fully understood. The aim of this project was therefore to bring more clarification about potential effects of those processes on the condition of silk samples treated with a set of different parameters for wavelength, pulse duration, energy density and number of pulses per spot. It also looks at the influence of the presence of soiling on the results. The analysis of potential effects was then carried out using statistical methods and advanced analytics. Scanning electron microscopy, Fourier-transform infrared spectroscopy and colorimetry technology provided the required insights to better assess the effects. Results show that laser cleaning of silk fibers, like most other conventional cleaning techniques, is not completely without risk, but knowing what the possible effects are helps making decisions on whether the benefits of the technique used justify these risks.
KW - Laser cleaning
KW - Cultural heritage
KW - Conservation
KW - Silk
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594601
DO - https://doi.org/10.1186/s40494-024-01152-1
SN - 2050-7445
VL - 12
IS - 1
SP - 1
EP - 15
PB - Springer
AN - OPUS4-59460
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bartels, Jan-Hauke
A1 - Xu, Ronghua
A1 - Kang, Chongjie
A1 - Herrmann, Ralf
A1 - Marx, Steffen
T1 - Experimental Investigation on the Transfer Behavior and Environmental Influences of Low-Noise Integrated Electronic Piezoelectric Acceleration Sensors
JF - Metrology
N2 - Acceleration sensors are vital for assessing engineering structures by measuring properties like natural frequencies. In practice, engineering structures often have low natural frequencies and face harsh environmental conditions. Understanding sensor behavior on such structures is crucial for reliable masurements. The research focus is on understanding the behavior of acceleration sensors in harsh environmental conditions within the low-frequency acceleration range. The main question is how to distinguish sensor behavior from structural influences to minimize errors in assessing engineering structure conditions. To investigate this, the sensors are tested using a long-stroke calibration unit under varying temperature and humidity conditions. Additionally, a mini-monitoring system configured with four IEPE sensors is applied to a small-scale support structure within a climate chamber. For the evaluation, a signal-energy approach is employed to distinguish sensor behavior from structural behavior. The findings show that IEPE sensors display temperature-dependent nonlinear transmission behavior within the low-frequency acceleration range, with humidity having negligible impact. To ensure accurate engineering structure assessment, it is crucial to separate sensor behavior from structural influences using signal energy in the time domain. This study underscores the need to compensate for systematic effects, preventing the underestimation of vibration energy at low temperatures and overestimation at higher temperatures when using IEPE sensors for engineering structure monitoring.
KW - Acceleration sensors
KW - Environmental influence
KW - IEPE
KW - Structural Health Monitoring
KW - Low-frequency shaker
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594623
UR - https://www.mdpi.com/2673-8244/4/1/4/
DO - https://doi.org/10.3390/metrology4010004
SN - 2673-8244
VL - 4
IS - 1
SP - 46
EP - 65
PB - MDPI
CY - Basel
AN - OPUS4-59462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stawski, Tomasz
A1 - Karafiludis, Stephanos
A1 - Pimentel, Carlos
A1 - Montes-Hernández, German
A1 - Kochovski, Zdravko
A1 - Bienert, Ralf
A1 - Weimann, Karin
A1 - Emmerling, Franziska
A1 - Scoppola, Ernesto
A1 - Van Driessche, Alexander E.S.
T1 - Solution-driven processing of calcium sulfate: The mechanism of the reversible transformation of gypsum to bassanite in brines
JF - Journal of Cleaner Production
N2 - Here, we show that calcium sulfate dihydrate (gypsum) can be directly, rapidly and reversibly converted to calcium sulfate hemihydrate (bassanite) in high salinity solutions (brines). The optimum conditions for the efficient production of bassanite in a short time (<5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the better-known behaviour of the bassanite phase in low-salt environments. In low-salinity aqueous solutions, bassanite is considered to be metastable with respect to gypsum and anhydrite, and therefore gypsum-to-bassanite conversion does not occur in pure water. Interestingly, the high-salinity transformation of gypsum-to-bassanite has been reported by many authors and used in practice for several decades, although its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures was inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline phase for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios.
KW - Industrial and Manufacturing Engineering
KW - Strategy and Management
KW - General Environmental Science
KW - Renewable Energy, Sustainability and the Environment
KW - Building and Construction
KW - Calcium sulfate
KW - Gypsum
KW - Bassanite
KW - Scattering
KW - Raman
KW - In situ
KW - Synchrotron
KW - BESSY
KW - MySpot
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594698
UR - https://www.sciencedirect.com/science/article/pii/S0959652624004591#appsec1
DO - https://doi.org/10.1016/j.jclepro.2024.141012
SN - 0959-6526
VL - 440
SP - 1
EP - 12
PB - Elsevier B.V.
AN - OPUS4-59469
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mrkwitschka, Paul
A1 - Rühle, Bastian
A1 - Kuchenbecker, Petra
A1 - Löhmann, Oliver
A1 - Lindemann, Franziska
A1 - Hodoroaba, Vasile-Dan
T1 - Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders
JF - Scientific Reports
N2 - Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed.
KW - Nanopowder
KW - Electron microscopy
KW - Sample preparation
KW - Cross-sectioning
KW - Cerium oxide
KW - Zinc oxide
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593289
DO - https://doi.org/10.1038/s41598-023-51094-0
SN - 2045-2322
VL - 14
SP - 1
EP - 10
PB - Springer Nature
CY - London
AN - OPUS4-59328
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Asna Ashari, Parsa
A1 - Oh, Hyochan
A1 - Koch, Claudia
T1 - Pathways to the hydrogen economy: A multidimensional analysis of the technological innovation systems of Germany and South Korea
JF - International Journal of Hydrogen Energy
N2 - The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry, politics, and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition, this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologies in Germany and South Korea, both recognized as global frontrunners in advancing and implementing hydrogen-based solutions. By providing a multidimensional assessment of pathways to the hydrogen economy, our analysis introduces two novel and crucial elements to the TIS analysis: (i) We integrate the concept of ‘quality infrastructure’ given the relevance of safety and quality assurance for technology adoption and social acceptance, and (ii) we emphasize the social perspective within the hydrogen TIS. To this end, we conducted 24 semi-structured expert interviews, applying qualitative open coding to analyze the data. Our results indicate that the hydrogen TISs in both countries have undergone significant developments across various dimensions. However, several barriers still hinder the further realization of a hydrogen economy. Based on our findings, we propose policy implications that can facilitate informed policy decisions for a successful hydrogen transition.
KW - Hydrogen economy
KW - Technological innovation system
KW - Quality infrastructure
KW - Multidimensional technology adoption
KW - Social acceptance
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593312
DO - https://doi.org/10.1016/j.ijhydene.2023.08.286
IS - Volume 49, Part D
SP - 405
EP - 421
PB - Elsevier
AN - OPUS4-59331
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Alekseychuk, V. O.
A1 - Kupsch, Andreas
A1 - Plotzki, D.
A1 - Bellon, Carsten
A1 - Bruno, Giovanni
T1 - Simulation-Assisted Augmentation of Missing Wedge and Region-of-Interest Computed Tomography Data
JF - Journal of Imaging
N2 - This study reports a strategy to use sophisticated, realistic X-ray Computed Tomography (CT) simulations to reduce Missing Wedge (MW) and Region-of-Interest (RoI) artifacts in FBP (Filtered Back-Projection) reconstructions. A 3D model of the object is used to simulate the projections that include the missing information inside the MW and outside the RoI. Such information augments the experimental projections, thereby drastically improving the reconstruction results. An X-ray CT dataset of a selected object is modified to mimic various degrees of RoI and MW problems. The results are evaluated in comparison to a standard FBP reconstruction of the complete dataset. In all cases, the reconstruction quality is significantly improved. Small inclusions present in the scanned object are better localized and quantified. The proposed method has the potential to improve the results of any CT reconstruction algorithm.
KW - Computed tomography
KW - Missing wedge
KW - Region of interest
KW - Augmented data
KW - CT simulation
KW - aRTist
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593799
UR - https://www.mdpi.com/2313-433X/10/1/11
DO - https://doi.org/10.3390/jimaging10010011
SN - 2313-433X
VL - 10
IS - 1
SP - 1
EP - 15
PB - MDPI
CY - Basel
AN - OPUS4-59379
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zia, Ghezal Ahmad Jan
A1 - Hanke, Thomas
A1 - Skrotzki, Birgit
A1 - Völker, Christoph
A1 - Bayerlein, Bernd
T1 - Enhancing Reproducibility in Precipitate Analysis: A FAIR Approach with Automated Dark-Field Transmission Electron Microscope Image Processing
JF - Integrating Materials and Manufacturing Innovation
N2 - AbstractHigh-strength aluminum alloys used in aerospace and automotive applications obtain their strength through precipitation hardening. Achieving the desired mechanical properties requires precise control over the nanometer-sized precipitates. However, the microstructure of these alloys changes over time due to aging, leading to a deterioration in strength. Typically, the size, number, and distribution of precipitates for a quantitative assessment of microstructural changes are determined by manual analysis, which is subjective and time-consuming. In our work, we introduce a progressive and automatable approach that enables a more efficient, objective, and reproducible analysis of precipitates. The method involves several sequential steps using an image repository containing dark-field transmission electron microscopy (DF-TEM) images depicting various aging states of an aluminum alloy. During the process, precipitation contours are generated and quantitatively evaluated, and the results are comprehensibly transferred into semantic data structures. The use and deployment of Jupyter Notebooks, along with the beneficial implementation of Semantic Web technologies, significantly enhances the reproducibility and comparability of the findings. This work serves as an exemplar of FAIR image and research data management.
KW - Industrial and Manufacturing Engineering
KW - General Materials Science
KW - Automated image analysis
KW - FAIR research data management
KW - Reproducibility
KW - microstructural changes
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593905
DO - https://doi.org/10.1007/s40192-023-00331-5
SN - 2193-9772
SP - 1
EP - 15
PB - Springer Science and Business Media LLC
CY - Heidelberg
AN - OPUS4-59390
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zuffa, Caterina
A1 - Cappuccino, Chiara
A1 - Casali, Lucia
A1 - Emmerling, Franziska
A1 - Maini, Lucia
T1 - Liquid reagents are not enough for liquid assisted grinding in the synthesis of (AgBr)(n-pica) n
JF - Physical Chemistry Chemical Physics
N2 - This study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)]n and [(AgBr)2(n-pica)]n to be obtained, and we report the new structures of [(AgBr)2(3-pica)]n and [(AgBr)2(4-pica)]n which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)]n/[(AgBr)2(n-pica)]n by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)]n is kinetically favoured while [(AgBr)2(3-pica)]n is converted into [(AgBr)(3-pica)]n only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile.
KW - Mechanochemistry
KW - Complex
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594755
DO - https://doi.org/10.1039/d3cp04791a
SN - 1463-9076
SP - 1
EP - 10
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59475
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwarz, I.
A1 - Rieck, Arielle
A1 - Mehmood, Asad
A1 - Bublitz, R.
A1 - Bongers, L.
A1 - Weuster-Botz, D.
A1 - Fellinger, Tim-Patrick
T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons
JF - European Chemical Societies Publishing
N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of −2.4 to −3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however required. Atomically-dispersed M−N−C catalysts show promise, if degradation throughout autoclaving can be omitted. The development of selective and autoclavable catalysts resistant to contamination and electrode design for the complex electrolyte will enable efficient bioelectrocatalytic power-to-X systems based on the introduced BES.
KW - Energy Conversion
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594766
DO - https://doi.org/10.1002/celc.202300344
SN - 2196-0216
SP - 1
EP - 10
PB - Wiley VHC-Verlag
AN - OPUS4-59476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Quackatz, Lukas
A1 - Griesche, Axel
A1 - Nietzke, Jonathan
A1 - Kannengießer, Thomas
T1 - In situ measurement of hydrogen concentration in steel using laser‑induced breakdown spectroscopy (LIBS)
JF - Welding in the World
N2 - The ISO 3690 standard “Determination of hydrogen content in arc weld metal” requires a thermal activation of the diffusible hydrogen in a piece of weld metal for the subsequent ex situ concentration measurement by carrier gas hot extraction CGHE or thermal desorption spectroscopy (TCD). Laser-induced breakdown spectroscopy (LIBS) offers a time and spatially resolved, almost non-destructive, in situ measurement of hydrogen at surfaces without sample preparation. We measured hydrogen in steels, which were charged either electrochemically or by high-pressure hydrogen gas, and compared the results. Further, the feasibility of quantitative hydrogen line scan measurements with LIBS was demonstrated by measuring hydrogen at water jet cut surfaces. The hydrogen concentrations measured with the help of LIBS were compared with CGHE measurements. It was observed that hydrogen can be reliably measured with LIBS for concentrations larger than 2 wt.-ppm. The maximum hydrogen concentration achieved using electrochemical charging was 85.1 ppm. The results show that LIBS is a promising technique for time- and spatially resolved measurements of hydrogen in steels.
T2 - IIW Annual Assembly 2023
CY - Singapore
KW - LIBS
KW - Hydrogen measurement
KW - Welding
KW - Stainless steel
KW - Diffusible hydrogen
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593664
DO - https://doi.org/10.1007/s40194-023-01677-2
SP - 1
EP - 9
PB - Springer
AN - OPUS4-59366
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Böllinghaus, Thomas
A1 - Cross, Carl
T1 - Obituary: Prof. Dr.-Ing. Hans Hoffmeister
JF - Welding in the World
N2 - On November 3, 2023, our dear colleague, Prof. Dr.-Ing. Hans Hoffmeister, born in 1932 in Kassel, Germany, passed away in Ahrensburg, near Hamburg, Germany.
KW - Metals and Alloys
KW - Mechanical Engineering
KW - Mechanics of Materials
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594160
DO - https://doi.org/10.1007/s40194-023-01675-4
SP - 1
EP - 2
PB - Springer Science and Business Media LLC
AN - OPUS4-59416
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weidner, Steffen
A1 - Meyer, A.
A1 - Falkenhagen, Jana
A1 - Kricheldorf, H. R.
T1 - Polycondensations and Cyclization of Poly(L-lactide) Ethyl Esters in the Solid State
JF - Polymer Chemistry
N2 - The usefulness of seven different Tin catalysts, Bismuth subsalicylate and Titan tetra(ethoxide) for the polycondensation of ethyl L-lactate (ELA) was examined at 150 °C/6 d. Dibutyltin bis(phenoxides) proved to be particularly effective. Despite the low reactivity of ELA, weight average molecular masses (Mw) up to 12 500 were found along with partial crystallization. Furthermore, polylactides (PLAs) of similar molecular masses were prepared via ELA-initiated ROPs of L-lactide by means of the four most effective polycondensation catalysts. The crystalline linear PLAs were annealed at 140 or 160 °C in the presence of these catalysts. The consequences of the transesterification reactions in the solid PLAs were studied by means of matrix-assisted laser desorption/ionization (MALDI TOF) mass spectrometry, gel permeation chromatography (GPC) and small-angle X-ray scattering (SAXS). The results indicate that polycondensation and formation of cycles proceed in the solid state via formation of loops on the surface of the crystallites. In summary, five different transesterification reactions are required to explain all results.
KW - Polylactide
KW - MALDI-TOF MS
KW - Crystalinity
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592934
DO - https://doi.org/10.1039/d3py01232h
SN - 1759-9962
VL - 15
IS - 2
SP - 71
EP - 82
PB - RSC Publ.
CY - Cambridge
AN - OPUS4-59293
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bayerlein, Bernd
A1 - Schilling, Markus
A1 - Birkholz, Henk
A1 - Jung, Matthias
A1 - Waitelonis, Jörg
A1 - Mädler, Lutz
A1 - Sack, Harald
T1 - PMD Core Ontology: Achieving semantic interoperability in materials science
JF - Materials and Design
N2 - Knowledge representation in the Materials Science and Engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant (consistent) and variant (context-specific) knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this paper, an approach how to maintain a comprehensive MSE-centric terminology composing a mid-level ontology–the Platform MaterialDigital Core Ontology (PMDco)–via MSE community-based curation procedures is presented. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics. Additionally, it demonstrates how the PMDco lowers development and integration thresholds. Moreover, the research highlights how to fuel it with real-world data sources ranging from manually conducted experiments and simulations with continuously automated industrial applications.
KW - Ontology
KW - Materials science and engineering
KW - Knowledge representation
KW - Reproducibility
KW - Semantic interoperability
KW - Semantic data integration
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592948
DO - https://doi.org/10.1016/j.matdes.2023.112603
SN - 0264-1275
VL - 237
SP - 1
EP - 12
PB - Elsevier
CY - Amsterdam
AN - OPUS4-59294
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klimek, André
A1 - Stelzner, Ludwig
A1 - Hothan, Sascha
A1 - Zehfuß, Jochen
T1 - Influence of thermal strain on concrete spalling
JF - Materials and Structures
N2 - Understanding the susceptibility to spalling of concrete members in case of fire is important to evaluate the residual load-bearing capacity. The investigations of the spalling phenomenon of a concrete mixture using real scale members are necessary but expensive to carry out. Reducing the specimen size leads to an increase of boundary effects that can result in a reduced spalling or absence of spalling. In this study, fire tests were carried out on unrestrained, single-sided exposed, cuboid shaped specimens (0.6 m x 0.6 m x 0.29 m) as well as unrestrained and steel ring restrained cylindrical specimens (Ø = 0.47 m, h = 0.29 m), which induce different boundary conditions. These fire tests were carried out on two ordinary concrete mixtures. The two mixtures differ only in the type of aggregates (quartz gravel and basalt grit) and were used to investigate the influence of the thermal expansion of the aggregate on the spalling behaviour of the concrete. The results show a significant increase of
the spalling depth due to the restrained thermal expansion achieved by the applied steel rings. Additionally, the type of aggregate has a direct influence on the spalling behaviour of a concrete mixture. The reduction of the boundary effects by the steel rings recreate the test conditions in the centre of a large concrete member. Thus, this type of specimen is suitable to determine the susceptibility to spalling of a material (screening-tests) as preliminary investigations to full scale fire tests.
KW - Spalling
KW - Concrete
KW - Fire test
KW - Restraint
KW - Screening test
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593350
DO - https://doi.org/10.1617/s11527-023-02274-x
VL - 57
SP - 1
EP - 14
PB - Springer
AN - OPUS4-59335
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heinekamp, Christian
A1 - Kneiske, Sönke
A1 - Guilherme Buzanich, Ana
A1 - Ahrens, Mike
A1 - Braun, Thomas
A1 - Emmerling, Franziska
T1 - A fluorolytic sol-gel route to access an amorphous Zr fluoride catalyst: A useful tool for C-F bond activation
JF - Catalysis Science & Technology
N2 - A route to a ZrF4 catalyst active in room temperature Friedel–Crafts and dehydrofluorination reactions was developed via a fluorolytic sol–gel route, which was followed by a postfluorination step using a stream of CHClF2. The behaviour of different Zr(IV) precursors in a sol–gel reaction with anhydrous isopropanol/HF solution was investigated. The subsequent post-fluorination step was optimised in its temperature ramp and confirmed the necessity of a fluorination of the generated xerogels to obtain catalytic activity. The process is discussed in the context of the analysis of the materials using Brunauer–Emmett–Teller analysis (BET), powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The local structure of the amorphous catalyst was elucidated by extended X-ray absorption fine structure spectroscopy (EXAFS).
KW - Catalysis
KW - Heterogeneous catalysis
KW - C-F bond activation
KW - Postfluorination
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593433
DO - https://doi.org/10.1039/D3CY01439H
SN - 2044-4761
SP - 1
EP - 8
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-59343
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wandtke, Karsten
ED - Becker, Amadeus
ED - Schröpfer, Dirk
ED - Kromm, Arne
ED - Kannengießer, Thomas
ED - Scharf-Wildenhain, R.
ED - Hälsig, A.
ED - Hensel, J.
T1 - Residual Stress Evolution during Slot Milling for Repair Welding and Wire Arc Additive Manufacturing of High-Strength Steel Components
JF - Welding of Modern High-Strength Steels — Correlations between Process, Structure and Joint Properties
N2 - High-strength steels offer potential for weight optimization due to reduced wall thicknesses in modern constructions. Additive manufacturing processes such as Wire Arc Additive Manufacturing (WAAM) enable the resource-efficient production of structures. In the case of defects occurring in weld seams orWAAM components due to unstable process conditions, the economical solution is local gouging or machining and repair welding. It is important to understand the effects of machining steps on the multiaxial stress state in conjunction with the design-related shrinkage restraints. Research into how welding and slot milling of welds andWAAM structures affects residual stresses is still lacking. For this reason, component-related investigations with high-strength steels with yield strengths ≥790 MPa are carried out in our research. In-situ digital image correlation (DIC) and ex-situ X-ray diffraction (XRD) were used to analyze the stresses and strains induced on specimens during and after milling. The systematic analyses revealed a significant interaction of the stiffness and microstructure of the specimens with the initial residual stresses induced by welding. Subsequent repair welds can result in significantly higher residual stresses.
KW - High strength steels
KW - Additive manufacturing
KW - Residual stress
KW - Repair welding
KW - Ditigtal image correlation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593515
DO - https://doi.org/10.3390/met14010082
VL - 14
IS - 1
SP - 1
EP - 11
PB - MDPI
CY - Basel
AN - OPUS4-59351
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rosen, Andrew S.
A1 - Gallant, Max
A1 - George, Janine
A1 - Riebesell, Janosh
A1 - Sahasrabuddhe, Hrushikesh
A1 - Shen, Jimmy-Xuan
A1 - Wen, Mingjian
A1 - Evans, Matthew L.
A1 - Petretto, Guido
A1 - Waroquiers, David
A1 - Rignanese, Gian-Marco
A1 - Persson, Kristin A.
A1 - Jain, Anubhav
A1 - Ganose, Alex M.
T1 - Jobflow: Computational Workflows Made Simple
JF - Journal of Open Source Software
N2 - We present Jobflow, a domain-agnostic Python package for writing computational workflows tailored for high-throughput computing applications. With its simple decorator-based approach, functions and class methods can be transformed into compute jobs that can be stitched together into complex workflows. Jobflow fully supports dynamic workflows where the full acyclic graph of compute jobs is not known until runtime, such as compute jobs that launch
other jobs based on the results of previous steps in the workflow. The results of all Jobflow compute jobs can be easily stored in a variety of filesystem- and cloud-based databases without the data storage process being part of the underlying workflow logic itself. Jobflow has been intentionally designed to be fully independent of the choice of workflow manager used to dispatch the calculations on remote computing resources. At the time of writing, Jobflow
workflows can be executed either locally or across distributed compute environments via an adapter to the FireWorks package, and Jobflow fully supports the integration of additional workflow execution adapters in the future.
KW - Automation
KW - Workflow
KW - Computational Materials Science
KW - Computations
KW - Software
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593104
DO - https://doi.org/10.21105/joss.05995
VL - 9
IS - 93
SP - 1
EP - 7
PB - The Open Journal
AN - OPUS4-59310
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Andreoli, A. F.
A1 - Fantin, Andrea
A1 - Kasatikov, S.
A1 - Bacurau, V. P.
A1 - Widom, M.
A1 - Gargarella, P.
A1 - Mazzer, E. M.
A1 - Woodcock, T. G.
A1 - Nielsch, K.
A1 - Coury, F. G.
T1 - The impact of chemical short-range order on the thermophysical properties of medium- and high-entropy alloys
JF - Materials & Design
N2 - The unusual behavior observed in the coefficient of thermal expansion and specific heat capacity of CrFeNi, CoCrNi, and CoCrFeNi medium/high-entropy alloys is commonly referred to as the K-state effect. It is shown to be independent of the Curie temperature, as demonstrated by temperature-dependent magnetic moment measurements. CoCrFeNi alloy is chosen for detailed characterization; potential reasons for the K-state effect such as texture, recrystallization, and second-phase precipitation are ruled out. An examination of the electronic structure indicates the formation of a pseudo-gap in the Density of States, which suggests a specific chemical interaction between Ni and Cr atoms upon alloying. Hybrid Monte Carlo/Molecular Dynamic (MC/MD) simulations indicate the presence of non-negligible chemical short-range order (CSRO). Local lattice distortions are shown to be negligible, although deviations around Cr and Ni elements from those expected in a fully disordered structure are experimentally observed by X-ray absorption spectroscopy. The determined bonding distances are in good agreement with MC/MD calculations. A mechanism is proposed to explain the anomalies and calorimetric experiments and their results are used to validate the mechanism.
KW - Mechanical Engineering
KW - Mechanics of Materials
KW - General Materials Science
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595869
DO - https://doi.org/10.1016/j.matdes.2024.112724
SN - 0264-1275
VL - 238
SP - 1
EP - 15
PB - Elsevier B.V.
AN - OPUS4-59586
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Was, G.S.
A1 - Bahn, C.-B.
A1 - Busby, J.
A1 - Cui, B.
A1 - Farkas, D.
A1 - Gussev, M.
A1 - Rigen He, M.
A1 - Hesterberg, J.
A1 - Jiao, Z.
A1 - Johnson, D.
A1 - Kuang, W.
A1 - McMurtrey, M.
A1 - Robertson, I.
A1 - Sinjlawi, A.
A1 - Song, M.
A1 - Stephenson, K.
A1 - Sun, K.
A1 - Swaminathan, Srinivasan
A1 - Wang, M.
A1 - West, E.
T1 - How irradiation promotes intergranular stress corrosion crack initiation
JF - Progress in Material Science
N2 - Irradiation assisted stress corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide.
KW - Irradiation
KW - Stress corrosion cracking
KW - Grain boundaries
KW - Oxidation
KW - Austenitic alloys
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595748
DO - https://doi.org/10.1016/j.pmatsci.2024.101255
SN - 0079-6425
VL - 143
SP - 1
EP - 15
PB - Elsevier
AN - OPUS4-59574
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohring, W.
A1 - Karafiludis, Stephanos
A1 - Manzoni, Anna M.
A1 - Laplanche, G.
A1 - Schneider, M.
A1 - Stephan-Scherb, C.
T1 - High-Temperature Corrosion of High- and Medium-Entropy Alloys CrMnFeCoNi and CrCoNi Exposed to a Multi-Oxidant Atmosphere H2O–O2–SO2
JF - High Entropy Alloys & Materials
N2 - AbstractThe high-temperature corrosion behaviors of the equimolar CrCoNi medium-entropy alloy and CrMnFeCoNi high-entropy alloy were studied in a gas atmosphere consisting of a volumetric mixture of 10% H2O, 2% O2, 0.5% SO2, and 87.5% Ar at 800 °C for up to 96 h. Both alloys were initially single-phase fcc with a mean grain size of ~ 50 μm and a homogeneous chemical composition. The oxide layer thickness of CrMnFeCoNi increased linearly with exposure time while it remained constant at ~ 1 μm for CrCoNi. A Cr2O3 layer and minor amounts of (Co,Ni)Cr2O4 developed on the latter while three oxide layers were detected on the former, i.e., a thin and continuous chromium rich oxide layer at the oxide/alloy interface, a dense (Mn,Cr)3O4 layer in the center and a thick and porous layer of Mn3O4 and MnSO4 at the gas/oxide interface. Additionally, a few metal sulfides were observed in the CrMnFeCoNi matrix. These results were found to be in reasonable agreement with thermodynamic calculations.
KW - high entropy alloys
KW - corrosion
KW - oxidation
KW - scanning electron microscopy
KW - sulfidation
KW - CrMnFeCoNi
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594189
DO - https://doi.org/10.1007/s44210-023-00026-8
SP - 1
EP - 17
PB - Springer Science and Business Media LLC
AN - OPUS4-59418
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -