TY - JOUR
A1 - Fasano, A.
A1 - Woyessa, G.
A1 - Stajanca, Pavol
A1 - Markos, C.
A1 - Stefani, A.
A1 - Nielsen, K.
A1 - Rasmussen, H. K.
A1 - Krebber, Katerina
A1 - Bang, O.
T1 - Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors
N2 - Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C. We also characterize the mPOF optically and mechanically, and further test the sensitivity of the PC FBG to strain and temperature. We demonstrate that the PC FBG can bear temperatures as high as 125°C without malfunctioning. In contrast, polymethyl methacrylate-based FBG technology is generally limited to temperatures below 90°C.
KW - Fiber optics sensors
KW - Fiber Bragg gratings
KW - Microstructured fibers
KW - Fiber characterization
KW - Polymers
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-355591
DO - https://doi.org/10.1364/OME.6.000649
SN - 2159-3930
VL - 6
IS - 2
SP - 649
EP - 659
PB - OSA Publishig
AN - OPUS4-35559
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Shapovalov, O.
A1 - Heckel, Thomas
A1 - Gaal, Mate
A1 - Weiß, S.
T1 - External Acoustical Damping on a Metallic Angle Wedge in a High Temperature Resistant Ultrasonic Probe
N2 - Ultrasonic probes for high-temperature applications are provided with metallic wedges, which can withstand the contact with the high temperature of the inspected structure. The ultrasonic signal travels within the wedge and gets reflected from its boundaries, causing interference signals called “ghost echoes”. The current work presents an investigation of the additional damping effect provided by porous sintered metal plates applied onto the surface of the wedge. In particular, the study evaluates the effect of damping plate thickness on the interference signal level at different transmission frequencies. Damping plates made of sintered metal SIKA-R 15 AX were attached to a wedge prototype made of steel 1.4301. The study revealed, that the most effective thickness of damping plates in the selected frequency interval of 1 to 4 MHz is equal to 4 mm. The evaluation of the interference signal has shown that the application of such damping plates to the wedge surface contributes to an additional attenuation of an interference signal of 10 to 30 dB after 500 μs of signal propagation.
KW - Ultrasonic testing
KW - High temperature
KW - Acoustical damping
KW - Angle wedge
KW - Ultrasonic probe
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-553920
DO - https://doi.org/10.1007/s40857-022-00270-9
SN - 0814-6039
SP - 1
EP - 11
PB - Springer
AN - OPUS4-55392
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Vecchiato, L.
A1 - Madia, Mauro
A1 - Meneghetti, G.
T1 - Extension of the peak stress method to estimate the fatigue limit of welded joints by means of the cyclic R-curve method
N2 - A new simplified and effective method has been formalised to estimate the Constant Amplitude Fatigue Limit (CAFL) of stress-relieved steel welded joints subjected to uniaxial push–pull loading and failing from the weld toe. Starting from the sharp V-notch assumption of the NSIF approach and the cyclic R-curve of the material in the heat affected zone, the proposed method identifies the CAFL as threshold level of the local stress field at the V-notched weld toe in the uncracked configuration. Such threshold stress field assures the crack arrest at the V-notched weld toe, according to the cyclic R-curve analysis. The method has been validated against experimental results and proved effective for a straightforward assessment of the CAFL of welded joints, as the stable crack propagation analysis of classical fracture mechanics approaches can be avoided.
KW - Cyclic R-curve
KW - Welded joint
KW - Fatigue limit
KW - Peak stress method
KW - Finite element analysis
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581059
DO - https://doi.org/10.1016/j.tafmec.2023.104039
SN - 0167-8442
VL - 127
SP - 1
EP - 19
PB - Elsevier
AN - OPUS4-58105
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pauw, Brian Richard
A1 - Smith, A. J.
A1 - Snow, T.
A1 - Shebanova, O.
A1 - Sutter, J. P.
A1 - Ilavsky, J.
A1 - Hermida-Merino, D.
A1 - Smales, Glen Jacob
A1 - Terrill, N. J.
A1 - Thünemann, Andreas
A1 - Bras, W.
T1 - Extending synchrotron SAXS instrument ranges through addition of a portable, inexpensive USAXS module with vertical rotation axes
N2 - Ultra-SAXS can enhance the capabilities of existing synchrotron SAXS/WAXS beamlines. A compact ultra-SAXS module has been developed, which extends the measurable q-range with 0.0015 ≤ q (nm−1) ≤ 0.2, allowing structural dimensions in the range 30 ≤ D (nm) ≤ 4000 to be probed in addition to the range covered by a high-end SAXS/WAXS instrument. By shifting the module components in and out on their respective motor stages, SAXS/WAXS measurements can be easily and rapidly interleaved with USAXS measurements. The use of vertical crystal rotation axes (horizontal diffraction) greatly simplifies the construction, at minimal cost to efficiency. In this paper, the design considerations, realization and synchrotron findings are presented. Measurements of silica spheres, an alumina membrane, and a porous carbon catalyst are provided as application examples.
KW - X-ray scattering
KW - Microstructure
KW - Instrumentation
KW - SAXS
KW - USAXS
KW - Nanostructure
KW - Combined techniques
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-524919
DO - https://doi.org/10.1107/S1600577521003313
SN - 1600-5775
VL - 28
IS - 3
SP - 824
EP - 833
PB - Wiley
CY - Oxford
AN - OPUS4-52491
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jacobson, D.
A1 - Darvishi Kamachali, Reza
A1 - Thompson, G. B.
T1 - Extending Density Phase-Field Simulations to Dynamic Regimes
N2 - Density-based phase-field (DPF) methods have emerged as a technique for simulating grain boundary thermodynamics and kinetics. Compared to the classical phase-field, DPF gives a more physical description of the grain boundary structure and chemistry, bridging CALPHAD databases and atomistic simulations, with broad applications to grain boundary and segregation engineering. Notwithstanding their notable progress, further advancements are still warranted in DPF methods. Chief among these are the requirements to resolve its performance constraints associated with solving fourth-order partial differential equations (PDEs) and to enable the DPF methods for simulating moving grain boundaries. Presented in this work is a means by which the aforementioned problems are addressed by expressing the density field of a DPF simulation in terms of a traditional order parameter field. A generic DPF free energy functional is derived and used to carry out a series of equilibrium and dynamic simulations of grain boundaries in order to generate trends such as grain boundary width vs. gradient energy coefficient, grain boundary velocity vs. applied driving force, and spherical grain radius vs. time. These trends are compared with analytical solutions and the behavior of physical grain boundaries in order to ascertain the validity of the coupled DPF model. All tested quantities were found to agree with established theories of grain boundary behavior. In addition, the resulting simulations allow for DPF simulations to be carried out by existing phase-field solvers.
KW - CALPHAD
KW - Phase-field modelling
KW - Phase-Field Simulations
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581365
DO - https://doi.org/10.3390/met13081497
VL - 13
SP - 1
EP - 16
AN - OPUS4-58136
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Maria
A1 - Güttler, Arne
A1 - Pauli, Jutta
A1 - Vogel, K.
A1 - Homann, Christian
A1 - Würth, Christian
A1 - Resch-Genger, Ute
T1 - Extending certified spectral fluorescence standards for the calibration and performance validation of fluorescence instruments to the NIR—closing the gap from 750 to 940 nm with two novel NIR dyes
N2 - Fluorescence techniques such as fluorescence spectroscopy, microfluorometry, and fluorescence microscopy, providing spectral, intensity, polarization, and lifetime information, are amongst the most broadly utilized analytical methods in the life and materials sciences. However, the measured fluorescence data contain sample- and instrument-specific contributions, which hamper their comparability across instruments and laboratories. Comparable, instrument-independent fluorescence data require the determination of the fluorescence instrument’s wavelength-dependent spectral responsivity, also termed emission correction curve, for the same instrument settings as those used for the fluorescence measurements as a prerequisite for the subsequent correction of the measured instrument-specific data. Such a spectral correction is essential for the performance comparison of different fluorescent labels and reporters, quantitative fluorescence measurements, the determination of the fluorescence quantum yield, and the spectroscopic measure for the fluorescence efficiency of a fluorophore. Simple-to-use tools for obtaining emission correction curves are chromophore-based reference materials (RMs), referred to as fluorescence standards, with precisely known, preferably certified instrument-independent fluorescence spectra. However, for the increasingly used near-infrared (NIR) wavelength region >700 nm, at present, no spectral fluorescence standards are available. To close this gap, we developed two novel spectral fluorescence standards, BAM F007 and BAM-F009, with broad emission bands from about 580 to 940 nm in ethanolic solution. These liquid fluorescence standards currently under certification, which will be released in 2025, will expand the wavelength range of the already available certified Calibration Kit BAM F001b-F005b from about 300–730 to 940 nm. In this research article, we will detail the criteria utilized for dye and matrix selection and the homogeneity and stability tests accompanying dye certification as well as the calculation of the wavelength-dependent uncertainty budgets of the emission spectra BAM F007 and BAM-F009, determined with the traceably calibrated BAM reference spectrofluorometer. These fluorescence standards can provide the basis for comparable fluorescence measurements in the ultraviolet, visible, and NIR for the fluorescence community.
KW - Quality assurance
KW - Reference material
KW - Fluorescence
KW - Dye
KW - Traceability
KW - Metrology
KW - Calibration
KW - Reference data
KW - Reference product
KW - Digital certificate
KW - NIR
KW - Instrument performance validation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626317
DO - https://doi.org/10.1007/s00216-024-05723-w
SN - 1618-2650
SP - 1
EP - 15
PB - Springer
AN - OPUS4-62631
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Keke
A1 - El-Sari, Bassel
A1 - Olfert, Viktoria
A1 - Wang, Zhuoqun
A1 - Biegler, Max
A1 - Rethmeier, Michael
A1 - Meschut, Gerson
T1 - Expulsion prevention in resistance spot welding of dissimilar joints with ultra-high strength steel: An analysis of the mechanism and effect of preheating current
N2 - The widespread adoption of ultra-high strength steels, due to their high bulk resistivity, intensifies expulsion issues in resistance spot welding (RSW), deteriorating both the spot weld and surface quality. This study presents a novel approach to prevent expulsion by employing a preheating current. Through characteristic analysis of joint formation under critical welding current, the importance of plastic material encapsulation around the weld nugget (plastic shell) at high temperatures in preventing expulsion is highlighted. To evaluate the effect of preheating on the plastic shell and understand its mechanism in expulsion prevention, a two-dimensional welding simulation model for dissimilar ultra-high strength steel joints was established. The results showed that optimal preheating enhances the thickness of the plastic shell, improving its ability to encapsulate the weld nugget during the primary welding phase, thereby diminishing expulsion risks. Experimental validation confirmed that by employing the optimal preheating current, the maximum nugget diameter was enhanced to 9.42 mm, marking an increase of 13.4 % and extending the weldable current range by 27.5 %. Under quasi-static cross-tensile loading, joints with preheating demonstrated a 7.9 % enhancement in maximum load-bearing capacity compared to joints without preheating, showing a reproducible and complete pull-out failure mode within the heat-affected zone. This study offers a prevention method based on underlying mechanisms, providing a new perspective for future research on welding parameter optimization with the aim of expulsion prevention.
KW - Resistance spot welding
KW - Finite element modelling
KW - Preheating
KW - Weldable current range
KW - Ultra-high strength steel
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-621719
DO - https://doi.org/10.1016/j.jmapro.2024.06.034
VL - 124
SP - 489
EP - 502
PB - Elsevier Ltd.
AN - OPUS4-62171
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bramke, K.
A1 - Müller, U.
A1 - McMahon, Dino Peter
A1 - Rolff, J.
T1 - Exposure of Larvae of the Solitary Bee Osmia bicornis to the Honey Bee Pathogen Nosema ceranae Aects Life History
N2 - Wild bees are important pollinators of wild plants and agricultural crops and they are threatened by several environmental stressors including emerging pathogens. Honey bees have been suggested as a potential source of pathogen spillover. One prevalent pathogen that has recently emerged as a honey bee disease is the microsporidian Nosema ceranae. While the impacts of N. ceranae in honey bees are well documented, virtually nothing is known about its effects in solitary wild bees.
The solitary mason bee Osmia bicornis is a common pollinator in orchards and amenable to Commercial management. Here, we experimentally exposed larvae of O. bicornis to food contaminated with N. ceranae and document spore presence during larval development. We measured mortality, growth parameters, and timing of pupation in a semi-field experiment. Hatched individuals were assessed for physiological state including fat body mass, wing muscle mass, and body size. We recorded higher mortality in the viable-spore-exposed group but could only detect a low number of Spores among the individuals of this treatment. Viable-spore-treated individuals with higher head capsule width had a delayed pupation start. No impact on the physiological status could be detected in hatched imagines. Although we did not find overt evidence of O. bicornis infection, our findings indicate that exposure of larvae to viable N. ceranae spores could affect bee development.
KW - Bee diseases
KW - Wild bees
KW - Nosema ceranae
KW - Osmia bicornis
KW - Pathogen transmission
KW - Solitary bees
KW - Bee health
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-496497
DO - https://doi.org/10.3390/insects10110380
VL - 10
IS - 11
SP - 380
PB - MDPI
AN - OPUS4-49649
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Spitzer, Stefan
A1 - Amyotte, P.
A1 - Salzano, E.
T1 - Explosion behavior of hybrid mixtures
N2 - Flammable mixtures of dusts with gases or liquids occur in the process and energy industries. Most research about these so-called "hybrid mixtures" was, and still is, about coal dust with the admixture of methane because of their occurrence in the mining industry. In the modern industry, hybrid mixture explosions play an increasing role in many existing processes like spray-drying, or in emerging technologies like the direct reduction of iron ore with hydrogen or nuclear/fusion reactors. While some safety characteristics of one of the component substances stay the same or are unaffected by the concentrations that occur in the process, others are severely influenced by only traces of the other substance.
This review paper shows in which processes and applications hybrid mixtures pose a risk and gives an overview of the research conducted in the last 150 years. Findings that are reproducible and represent current proven knowledge are stated and compared to each safety characteristic containing only solid particles, gases or liquids as combustible substances. Additionally, fundamental studies on the mechanisms of flame propagation in hybrid mixtures are reviewed. The significance of these studies in enhancing our understanding of explosion behaviors in hybrid mixtures is also discussed. An outlook on what has been missing so far in the literature, is also given comparing the knowledge of single substances with their mixtures, why this might not have been investigated, and where the challenges lie.
KW - Hybrid mixtures
KW - Safety characteristics
KW - Combustion regimes
KW - Industrial explosions
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654013
DO - https://doi.org/10.1016/j.pecs.2025.101276
SN - 0360-1285
VL - 113
SP - 1
EP - 24
PB - Elsevier
CY - Amsterdam
AN - OPUS4-65401
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ghata, Anupama
A1 - Bernges, Tim
A1 - Maus, Oliver
A1 - Wankmiller, Björn
A1 - Naik, Aakash
A1 - Bustamante, Joana
A1 - Gaultois, Michael W.
A1 - Delaire, Olivier
A1 - Hansen, Michael Ryan
A1 - George, Janine
A1 - Zeier, Wolfgang G.
T1 - Exploring the Thermal and Ionic Transport of Cu+ Conducting Argyrodite Cu7PSe6
N2 - AbstractUnderstanding the origin of low thermal conductivities in ionic conductors is essential for improving their thermoelectric efficiency, although accompanying high ionic conduction may present challenges for maintaining thermoelectric device integrity. This study investigates the thermal and ionic transport in Cu7PSe6, aiming to elucidate their fundamental origins and correlation with the structural and dynamic properties. Through a comprehensive approach including various characterization techniques and computational analyses, it is demonstrated that the low thermal conductivity in Cu7PSe6 arises from structural complexity, variations in bond strengths, and high lattice anharmonicity, leading to pronounced diffuson transport of heat and fast ionic conduction. It is found that upon increasing the temperature, the ionic conductivity increases significantly in Cu7PSe6, whereas the thermal conductivity remains nearly constant, revealing no direct correlation between ionic and thermal transport. This absence of direct influence suggests innovative design strategies in thermoelectric applications to enhance stability by diminishing ionic conduction, while maintaining low thermal conductivity, thereby linking the domains of solid‐state ionics and thermoelectrics. Thus, this study attempts to clarify the fundamental principles governing thermal and ionic transport in Cu+‐superionic conductors, similar to recent findings in Ag+ argyrodites.
KW - Thermoelectrics
KW - Phonons
KW - Chemically Complex Materials
KW - DFT
KW - Bonding Analysis
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-608866
DO - https://doi.org/10.1002/aenm.202402039
SP - 1
EP - 9
PB - Wiley
AN - OPUS4-60886
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Scheurrell, Kerstin
A1 - B. Martins, Inês C.
A1 - Murray, Claire
A1 - Emmerling, Franziska
T1 - Exploring the role of solvent polarity in mechanochemical Knoevenagel condensation: in situ investigation and isolation of reaction intermediates
N2 - Mechanochemistry has proven to be a highly effective method for the synthesis of organic compounds. We studied the kinetics of the catalyst-free Knoevenagel reaction between 4-nitrobenzaldehyde and malononitrile, activated and driven by ball milling. The reaction was investigated in the absence of solvents (neat grinding) and in the presence of solvents with different polarities (liquid-assisted grinding). The reaction was monitored using time-resolved in situ Raman spectroscopy and powder X-ray diffraction (PXRD). Our results indicate a direct relationship between solvent polarity and reaction kinetics, with higher solvent polarity leading to faster product (2-(4-nitrobenzylidone)malononitrile) formation. For the first time, we were able to isolate and determine the structure of an intermediate 2-(hydroxy(4-nitrophenyl)methyl)malononitrile based on PXRD data.
KW - Physical and Theoretical Chemistry
KW - General Physics and Astronomy
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-588071
DO - https://doi.org/10.1039/D3CP02883F
SN - 1463-9076
VL - 25
IS - 35
SP - 23637
EP - 23644
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-58807
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Golub, Tino Petar
A1 - Meyer, Klas
A1 - Paul, Andrea
A1 - Kipphardt, Heinrich
A1 - Tuma, Dirk
T1 - Exploring the potential of a setup for combined quantification of hydrogen in natural gas – Raman and NMR spectroscopy
N2 - An accurate measurement of the amount fraction of hydrogen in gas mixtures is mandatory for practical applications, requiring methods that are fast, continuous, robust, and cost-effective. This study compares the performance of Raman and benchtop NMR process spectroscopy for determining the hydrogen amount fraction in gas mixtures. A setup was designed to integrate both techniques, enabling measurements of the same sample.
Tests were conducted with gravimetrically prepared gas mixtures of reference quality ranging from 1.20 cmol/mol to 85.83 cmol/mol of hydrogen. The results demonstrate that Raman spectroscopy provides superior performance, with a minimal root mean square error (RMSE) of 0.22 cmol/mol and excellent linearity. In contrast, benchtop NMR spectroscopy faced challenges, such as overlapping peaks and longer measurement times, resulting in a higher RMSE of 0.71 cmol/mol. Raman spectroscopy proves to be particularly well-suited for
practical applications due to its high accuracy and linearity. Meanwhile, benchtop NMR spectroscopy holds potential for future enhancements through ongoing technological advances, such as higher magnetic field strengths. In summary, the results from our study indicate that Raman spectroscopy is already a serviceable method for precise hydrogen quantification, whereas benchtop NMR spectroscopy can be attributed potential for future applications.
KW - Hydrogen amount fraction
KW - Raman spectroscopy
KW - NMR spectroscopy
KW - Field applicability
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-610093
DO - https://doi.org/10.1016/j.saa.2024.125087
SN - 1386-1425
VL - 325
SP - 1
EP - 9
PB - Elsevier B.V.
CY - Amsterdam
AN - OPUS4-61009
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Rabe, Sebastian
A1 - Chuenban, Yuttapong
A1 - Schartel, Bernhard
T1 - Exploring the Modes of Action of Phosphorus-Based Flame Retardants in Polymeric Systems
N2 - Phosphorus-based flame retardants were incorporated into different, easily preparable matrices, such as polymeric thermoset resins and paraffin as a proposed model for polyolefins and investigated for their flame retardancy performance. The favored mode of action of each flame retardant was identified in each respective system and at each respective concentration. Thermogravimetric analysis was used in combination with infrared spectroscopy of the evolved gas to determine the pyrolysis behavior, residue formation and the release of phosphorus species. Forced flaming tests in the cone calorimeter provided insight into burning behavior and macroscopic residue effects. The results were put into relation to the phosphorus content to reveal correlations between phosphorus concentration in the gas phase and flame inhibition performance, as well as phosphorus concentration in the residue and condensed phase activity. Total heat evolved (fire load) and peak heat release rate were calculated based on changes in the effective heat of combustion and residue, and then compared with the measured values to address the modes of action of the flame retardants quantitatively. The quantification of flame inhibition, charring, and the protective layer effect measure the non-linear flame retardancy effects as functions of the phosphorus concentration. Overall, this screening approach using easily preparable polymer systems provides great insight into the effect of phosphorus in different flame retarded polymers, with regard to polymer structure, phosphorus concentration, and phosphorus species.
KW - Flame retardants
KW - Flame inhibition
KW - Cone calorimeter
KW - Aluminum diethyl phosphinate
KW - Polyester
KW - PMMA
KW - Epoxy resin
KW - Red phosphorus
KW - BDP
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402731
DO - https://doi.org/10.3390/ma10050455
SN - 1996-1944
VL - 10
IS - 5
SP - 455, 1
EP - 455, 23
PB - MDPI
AN - OPUS4-40273
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Teixeira, M.M.
A1 - Moreno, L.F.
A1 - Stielow, B.J.
A1 - Muszewska, A.
A1 - Hainaut, M.
A1 - Gonzaga, L.
A1 - Abouelleil, A.
A1 - Patan, J.S.L.
A1 - Priest, M.
A1 - Souza, R.
A1 - Ferreira, K.S.
A1 - Zeng, Q.
A1 - da Cunha, M.M.L.
A1 - Gladki, A.
A1 - Barker, B.
A1 - Vicente, V.A.
A1 - de Souza, E.M.
A1 - Almeida, S.
A1 - Henrissat, B.
A1 - Vasconelos, A.T.R.
A1 - Deng, S.
A1 - Vogelmayr, H.
A1 - Moussa, T.A.A.
A1 - Gorbushina, Anna
A1 - Felipe, M.S.S.
A1 - Cuomo, C.A.
A1 - de Hoog, G.S.
T1 - Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota)
N2 - The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sexrelated genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi.
KW - Black yeast
KW - Comparative genomics
KW - Chaetothyriales
KW - Ecology
KW - Evolution
KW - Herpotrichiellaceae
KW - Phylogeny
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-408720
DO - https://doi.org/10.1016/j.simyco.2017.01.001
SN - 1872-9797
VL - 86
IS - 1
SP - 1
EP - 28
PB - Elsevier
CY - Amsterdam
AN - OPUS4-40872
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Weiss, Daniel
A1 - Asna Ashari, Parsa
A1 - Blind, Knut
T1 - Exploring the fuel-cell technological innovation system: Technology interactions in the mobility sector
N2 - With the rise of alternative sustainable powertrain technologies, the mobility paradigm has undergone fundamental changes in recent years. In the wake of the ongoing transition of the road-vehicle sector, fuel-cell vehicles (FCVs) have received increased political attention. However, they constitute only a tiny fraction of total road vehicles nowadays and still face competition from other powertrain technologies. Therefore, this study specifically focuses on how the focal technological innovation system of FCVs is influenced by the emerging electric vehicles (EVs) and established internal combustion engine vehicles (ICEVs) as its context structures. To this end, our time-series vector error correction models analyze the short- and long-run causalities between our focal TIS and its context structures. Using publications, patents, and standards as quantitative TIS indicators, we analyze the modes of technology interaction between FCVs and EVs and FCVs and ICEVs to determine the life-cycle phase of our focal FCV-TIS in more depth. Our results demonstrate that the FCV-TIS is in its formative phase based on the dominance of the EV and ICEV context structures. As policy implications, we derive application-sensitive technology policies that combine the benefits of each mobility technology toward the sustainable transition of the mobility sector.
KW - Technological innovation system (TIS)
KW - Technology interaction
KW - TIS-context relations
KW - Fuel-cell vehicles
KW - Electric vehicles
KW - Internal combustion engine vehicles
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-626599
DO - https://doi.org/10.1016/j.trip.2024.101107
SN - 2590-1982
VL - 25
SP - 1
EP - 15
PB - Elsevier
CY - Amsterdam
AN - OPUS4-62659
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Santi, Alberto
A1 - Schröder, Jakob
A1 - Serrano-Munoz, Itziar
A1 - Bayat, Mohamad
A1 - Hattel, Jesper Henri
T1 - Exploring the Flash Heating method in additive manufacturing for residual stress prediction: A comparative study with diffraction results from X-ray and neutron techniques
N2 - Residual stress (RS) control is crucial for ensuring the performance and reliability of components produced through laser-based powder bed fusion (PBF-LB) additive manufacturing (AM). This study evaluates the Flash Heating (FH) method as an efficient approach for RS prediction, comparing its outcomes with multiple experimental techniques, including X-ray diffraction, neutron diffraction, and layer removal methods. These experimental assessments are conducted in different regions of the component, both before and after detachment from the baseplate. The study validates the FH method and analyzes key numerical parameters, such as meta-layer height, contact time, and time-stepping strategies. Results indicate that FH effectively predicts bulk RS distributions but shows discrepancies in surface stress estimations, likely due to unaccounted factors like surface roughness. Additionally, implementing experimentally derived material properties from as-built AM samples significantly enhances model accuracy compared to conventional material datasets. These findings underscore the potential of FH for efficient RS prediction in PBF-LB while identifying areas for further improvement. Refinements should focus on incorporating anisotropic, temperature-dependent material behavior derived from as-built AM samples and surface roughness effects. This work advances the understanding of key factors necessary for accurate and computationally efficient RS prediction, supporting the optimization of AM processes.
KW - Finete element method
KW - Inconel 718
KW - Metal additive manufacturing
KW - Residual stress
KW - Thermomechanics
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-639533
DO - https://doi.org/10.1080/01495739.2025.2541862
SN - 0149-5739
SP - 1
EP - 24
PB - Taylor & Francis
AN - OPUS4-63953
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Leonhardt, Robert
A1 - Böttcher, Nils
A1 - Dayani, Shahabeddin
A1 - Rieck, Arielle
A1 - Markötter, Henning
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Tichter, Tim
A1 - Krug von Nidda, Jonas
T1 - Exploring the electrochemical and physical stability of lithium-ion cells exposed to liquid nitrogen
N2 - The transport and storage of lithium-ion (Li-ion) batteries — damaged or in an undefined state — is a major safety concern for regulatory institutions, transportation companies, and manufacturers. Since (electro)chemical reactivity is exponentially temperature-dependent, cooling such batteries is an obvious measure for increasing their safety.
The present study explores the effect of cryogenic freezing on the electrochemical and physical stability of Li-ion cells. For this purpose, three different types of cells were repeatedly exposed to liquid nitrogen (LN2).
Before and after each cooling cycle, electrical and electrochemical measurements were conducted to assess the impact of the individual freezing steps. While the electrochemical behavior of the cells did not change significantly upon exposure to LN2 , it became apparent that a non-negligible number of cells suffered from physical changes (swelling) and functional failures. The latter defect was found to be caused by the current interrupt device of the cylindrical cells. This safety mechanism is triggered by the overpressure of expanding nitrogen which enters the cells at cryogenic temperatures.
This study underlines that the widely accepted reversibility of LN2 -cooling on a material scale does not allow for a direct extrapolation toward the physical integrity of full cells. Since nitrogen enters the cell at cryogenic temperatures and expands upon rethermalization, it can cause an internal overpressure. This can, in turn, lead to mechanical damage to the cell. Consequently, a more appropriate temperature condition — less extreme than direct LN2 exposure — needs to be found
KW - Lithium-ion battery
KW - LN2 cooling
KW - Battery characterization
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599248
DO - https://doi.org/10.1016/j.est.2024.111650
VL - 89
SP - 1
EP - 7
PB - Elsevier B.V.
AN - OPUS4-59924
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Resch-Genger, Ute
A1 - Brunet, G.
A1 - Marin, R.
A1 - Monk, Melissa-Jane
A1 - Galico, D. A.
A1 - Sigoli, F. A.
A1 - Suturina, E. A.
A1 - Hemmer, E.
A1 - Murugesu, M.
T1 - Exploring the dual functionality of an Ytterbium complex for luminescence thermometry and slow magnetic relaxation†
N2 - We present a comprehensive investigation of the magnetic and optical properties of an ytterbium complex, which combines two desirable and practical features into a single molecular system. Based upon YbIII Ions that promote near-infrared optical activity and a chemical backbone that is ideal for an in-depth understanding of the magnetic behaviour, we have designed a multifunctional opto-magnetic species that operates as a luminescent thermometer and as a single-molecule magnet (SMM). Our magnetic investigations, in conjunction with ab initio calculations, reveal one of the highest energy barriers reported for an YbIII-based complex. Moreover, we correlate this anisotropic barrier with the Emission spectrum of the compound, wherein we provide a complete assignment of the energetic profile of the complex. Such studies lay the foundation for the design of exciting multi-faceted materials that are able to retain information at the single-molecule level and possess built-in thermal self-monitoring capabilities.
KW - Magnetic
KW - Fluorescence
KW - NIR
KW - Temperature
KW - Dual sensing
KW - Sensor
KW - Yb(III) complex
KW - Lanthanide
KW - Quantum yield
KW - Quality assurance
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-486659
DO - https://doi.org/10.1039/c9sc00343f
VL - 10
IS - 28
SP - 6799
EP - 6808
PB - Royal Society of Chemistry
AN - OPUS4-48665
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mishurova, Tatiana
A1 - Artzt, K.
A1 - Haubrich, J.
A1 - Requena, G.
A1 - Bruno, Giovanni
T1 - Exploring the correlation between subsurface residual stresses and manufacturing parameters in laser powder bed fused Ti-6Al-4V
N2 - Subsurface residual stresses (RS) were investigated in Ti-6Al-4V cuboid samples by means of X-ray synchrotron diffraction. The samples were manufactured by laser powder bed fusion (LPBF) applying different processing parameters, not commonly considered in open literature, in order to assess their influence on RS state. While investigating the effect of process parameters used for the calculation of volumetric energy density (such as laser velocity, laser power and hatch distance), we observed that an increase of energy density led to a decrease of RS, although not to the same extent for every parameter variation. Additionally, the effect of support structure, sample roughness and LPBF machine effects potentially coming from Ar flow were studied. We observed no influence of support structure on subsurface RS while the orientation with respect to Ar flow showed to have an impact on RS.We conclude recommending monitoring such parameters to improve part reliability and reproducibility.
KW - Additive manufacturing
KW - Synchrotron X-ray diffraction
KW - Residual stress
KW - Ti-6Al-4V
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-474281
DO - https://doi.org/10.3390/met9020261
SN - 2075-4701
VL - 9
IS - 2
SP - 261, 1
EP - 13
PB - MDPI
AN - OPUS4-47428
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Filimonova, S. M.
A1 - Melnikov, E. S.
A1 - Kaufmann, Jan Ole
A1 - Shchepochkina, O. Y.
A1 - Eremin, S. A.
A1 - Gravel, I. V.
A1 - Raysyan, Anna
T1 - Exploring the anti‐α‐amylase activity of flavonoid aglycones in fabaceae plant extracts: a combined MALDI‐TOF‐MS and LC–MS/MS approach
N2 - A combination of TLC-bioautography, MALDI-TOF-MS and LC–MS/MS methods was used to identify flavonoids with anti-α-amylase activity in extracts of Lathyrus pratensis L. (herb), L. polyphillus L. (fruits), Thermopsis lanceolata R. Br. (herb) and S. japonica L. (buds). After the TLC-autobiography assay, substances with anti-amylase activity were identified by MALDI-TOF-MS followed by confirmation of the result by LC–MS/MS. Results of the study revealed that the flavonoids apigenin, luteolin, formononetin, genistein and kaempferol display marked anti-α-amylase activity. Formononetin showed the largest activity. Compared with LC–MS/MS, MALDI-TOF-MS is a quick and convenient method; results can be obtained within minutes; and only minor sample amounts are required which allows us to analyse mixtures of substances without preliminary separation. However, the inability to distinguish between isomers is the main limitation of the method.
KW - Enzyme
KW - MALDI-TOF-MS
KW - LC-MS/MS
KW - Massenspektrometrie
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-577128
DO - https://doi.org/https://doi.org/10.1111/ijfs.16491
SN - 0950-5423
VL - 58
IS - 7
SP - 3902
EP - 3911
PB - Wiley & Sons
CY - Hoboken, NJ, USA
AN - OPUS4-57712
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirtsch, Mona
A1 - Kinne, J.
A1 - Blind, K.
T1 - Exploring the Adoption of the International Information Security Management System Standard ISO/IEC 27001: A Web Mining-Based Analysis
N2 - In the light of digitalization and recent EU policy initiatives, information is an important asset that organizations of all sizes and from all sectors should secure. However, in order to provide common requirements for the implementation of an information security management system, the internationally well-accepted ISO/IEC 27001 standard has not shown the expected growth rate since its publication more than a decade ago.In this article, we apply web mining to explore the adoption of ISO/IEC 27001 through a series of 2664 out of more than 900 000 German firms from the Mannheim Enterprise Panel dataset that refers to this standard on their websites. As a result, we present a “landscape” of ISO/IEC 27001 in Germany, which shows that firms not only seek certifications themselves but often refer on their websites to partners who are certified instead. Consequently, we estimate a probit model and find that larger and more innovative firms are more likely to be certified to ISO/IEC 27001 and that almost half of all certified firms belong to the information and communications technology (ICT) service sector. Based on our findings, we derive implications for policymakers and management and critically assess the suitability of web mining to explore the adoption of management system standards.
KW - Adoption
KW - Information security
KW - Management system standards
KW - Standards
KW - Web mining
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-513284
DO - https://doi.org/10.1109/TEM.2020.2977815
VL - 68
IS - 1
SP - 87
EP - 100
AN - OPUS4-51328
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
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 - Scharpmann, Philippa
A1 - Leonhardt, Robert
A1 - Schmidt, Anita
A1 - Kowal, Julia
A1 - Tichter, Tim
A1 - Krug von Nidda, Jonas
T1 - Exploring restrictive overdischarge cycling as a method to accelerate characteristic ageing in lithium-ion cells
N2 - This study presents a test protocol that greatly accelerates the ageing process of lithium-ion battery cells comprising a positive electrode of nickel manganese cobalt oxide while preserving their characteristic degradation upon cyclic ageing. Applying a repetitive restricted overdischarge, resulting in a depth of discharge larger than 100%, a capacity loss of 20% is achieved over five times faster compared to conventional cycling. The well-known overdischarge degradation phenomenon of copper current collector dissolution is deliberately prevented by setting a discharge cutoff voltage above the theoretical threshold of copper oxidation. Hence, the accelerated degradation can be primarily connected to solid electrolyte interphase growth.
A comparative assessment of the ageing dynamics using electrochemical impedance spectroscopy and differential voltage analysis hints towards similar, characteristic degradation processes during accelerated and conventional ageing. A post-ageing examination of the electrical behaviour (i.e., coulombic and energy efficiency, capacity fade) under reference conditions reveals very little to no lasting damages caused by
overdischarging. Additionally, post-mortem analysis discloses no increased copper dissolution when comparing cells subjected to accelerated and conventional ageing. Generally, the developed ageing method appears suitable for providing cells with a defined state of health at a reasonable timescale without altering the main degradation mechanisms significantly.
KW - Lithium-ion cell
KW - Accelerated ageing
KW - Overdischarge
KW - Degradation processes
KW - Differential voltage analysis
KW - Electrochemical impedance spectroscopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650917
DO - https://doi.org/10.1016/j.jpowsour.2025.239072
SN - 0378-7753
VL - 665
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65091
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Radtke, Martin
A1 - Emmerling, Franziska
ED - Rogge, Andreas
ED - Meng, Birgit
T1 - Exploring new materials for Green Intelligent Building - How can our BAMline help?
N2 - In the scope of exploring and characterizing new materials related to Green Intelligent Building (GIB), we will provide an overview of the X-ray spectroscopy and diffraction analytical methods available at the BAMline /1/. and Myspot beamlines. These are two universal beamlines at the Berlin Synchrotron BESSY-II, where BAM has access and supervision role. Overarching electronic and structural properties at different time and length scales, such measurements enable a real-time characterization of materials properties. We will show-case in situ and ex situ deterioration and hydration studies on cement-based constructure materials.
T2 - 11. Jahrestagung des DAfStb mit 63. Forschungskolloquium der BAM Green Intelligent Building
CY - Berlin, Germany
DA - 16.10.2024
KW - BAMline
KW - Scope of exploring
KW - Green intelligent building
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-612882
SN - 978-3-9818564-7-7
SP - 30
EP - 36
PB - Bundesanstalt für Materialforschung und -prüfung (BAM)
CY - Berlin
AN - OPUS4-61288
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tamburini, Federica
A1 - Kluge, Martin
A1 - Habib, Abdel Karim
A1 - Ustolin, Federico
A1 - Cozzani, Valerio
A1 - Paltrinieri, Nicola
T1 - Exploring experimental tests concerning liquid hydrogen releases
N2 - In recent years, the adoption of liquid hydrogen (LH2) has increased significantly in industrial and transport applications, driven by its low carbon footprint, thereby aiding the fight against global warming. Additionally, its high volumetric energy density, compared to gaseous or compressed hydrogen, enhances hydrogen storage capabilities.
However, safety remains a major concern due to its physical-chemical properties and inherent hazardous characteristics, especially in the event of spillage scenarios. Therefore, to better understand the consequences of LH2 releases onto or into water, large-scale experimental tests were conducted by Bundesanstalt für Materialforschung und -prüfung (BAM) within the Safe Hydrogen Fuel Handling and Use for Efficient Implementation (SH2IFT) project at the Test Site Technical Safety of BAM, comprising 75 single spill events at varied release rates and orientations. While the rapid phase transition (RPT) phenomenon was not observed, selfignition of the hydrogen-air cloud occurred, accompanied by blast wave overpressure and heat radiation, without a discernible ignition source. These findings emphasize the need for further investigation into LH2 safety. Leveraging experimental data for real-world applications provides insights into safe LH2 infrastructure implementation, laying foundational knowledge for addressing safety challenges and advancing LH2 technology.
KW - Liquid Hydrogen
KW - Rapid phase transition
KW - Ignition
KW - Safety
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-618644
DO - https://doi.org/10.1016/j.psep.2024.11.014
SN - 0957-5820
VL - 192
SP - 1330
EP - 1343
PB - Elsevier
CY - Amsterdam
AN - OPUS4-61864
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Morcillo, Dalia
A1 - Winckelmann, Alexander
A1 - Oelze, Marcus
A1 - Leonhardt, Robert
A1 - Schmidt, Anita
A1 - Richter, Silke
A1 - Recknagel, Sebastian
A1 - Vogl, Jochen
A1 - Panne, Ulrich
A1 - Abad Andrade, Carlos Enrique
T1 - Exploring Age-Induced Lithium Isotope Fractionation in Lithium-Ion Batteries using Microwave-Induced Cold Nitrogen Plasma Mass Spectrometry
N2 - This study explores Microwave-Inductively Coupled Atmospheric-pressure Plasma Mass Spectrometry (MICAP-MS) as a cost-effective alternative to Multi-Collector Inductively Coupled Plasma Mass Spectrometry (MC-ICP-MS) for analyzing lithium isotopic composition in lithium-ion batteries (LIBs). We investigate the performance of MICAP-MS in measuring Li isotope ratios in new and aged commercial lithium cobalt oxide (LCO) batteries. Our results show that MICAP-MS, operating under cold plasma conditions at 800 W with an 8 mm torch position, achieves results metrologically compatible with MC-ICP-MS, with a precision ranging from 0.6‰ to 3.4‰ for δ7Li values. MICAP-MS benefits from a dielectric resonator for uniform plasma, better ion velocity control, and higher energy efficiency. Optimal settings were identified with dwell times of 10 ms for 6Li and 1 ms for 7Li. The study of LIBs revealed that 6Li migrates towards the anode over multiple charge–discharge cycles, causing 7Li to accumulate in the cathode, a fractionation effect that becomes more pronounced with prolonged cycling. MICAP-MS provides a cost-effective, precise alternative to MC-ICP-MS, with lower operational costs and enhanced portability, advancing the study of isotopic fractionation and aging in lithium-ion batteries.
KW - MICAP-MS
KW - Lithium
KW - Battery aging
KW - Lithium isotopes
KW - Nitrogen plasma
KW - Isotope fractionation
KW - lithium cobalt oxide
KW - LCO
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643777
DO - https://doi.org/10.1039/d4ja00324a
SN - 0267-9477
SP - 1
EP - 11
PB - Royal Society of Chemistry (RSC)
AN - OPUS4-64377
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Otto, Peter
A1 - de Lorenzis, L.
A1 - Unger, Jörg F.
T1 - Explicit dynamics in impact simulation using a NURBS contact interface
N2 - In this paper, the impact problem and the subsequent wave Propagation are considered. For the contact discretization an intermediate non-uniform rational B-spline (NURBS) layer is added between the contacting finite element bodies, which allows a smooth contact formulation and efficient element-based integration.
The impact event is ill-posed and requires a regularization to avoid propagating stress oscillations. A nonlinear mesh-dependent penalty regularization is used, where the stiffness of the penalty regularization increases upon mesh refinement. Explicit time integration methods are well suited for wave propagation problems, but are efficient only for diagonal mass matrices. Using a spectral element discretization in combination with a NURBS contact layer the bulk part of the mass matrix is diagonal.
KW - Explicit dynamics
KW - Impact simulation
KW - Isogeometric analysis
KW - mortar method
KW - spectral elements
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506041
DO - https://doi.org/10.1002/nme.6264
VL - 121
IS - 6
SP - 1248
EP - 1267
PB - Wiley Online Libary
AN - OPUS4-50604
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Otto, Peter
A1 - Lorenzis, L.
A1 - Unger, Jörg F.
T1 - Explicit dynamics in impact simulation using a NURBS contact interface
N2 - In this paper, the impact problem and the subsequent wave propagation are considered. For the contact discretization an intermediate NURBS layer is added between the contacting finite element bodies, which allows a smooth contact formulation and efficient element‐based integration. The impact event is ill‐posed and requires a regularization to avoid propagating stress oscillations. A nonlinear mesh dependent penalty regularization is used, where the stiffness of the penalty regularization increases upon mesh refinement. Explicit time integration methods are well suited for wave propagation problems, but are efficient only for diagonal mass matrices. Using a spectral element discretization and the coupled FE‐NURBS approach the bulk part of the mass matrix is diagonal.
KW - Impact simulation
KW - Explicit dynamics
KW - Isogeometric analysis
KW - Spectral elements
KW - Mortar method
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-494947
DO - https://doi.org/10.1002/nme.6264
SP - 1
EP - 21
PB - Wiley Online Libary
AN - OPUS4-49494
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Evsevleev, Sergei
A1 - Sevostianov, I.
A1 - Mishurova, Tatiana
A1 - Hofmann, M.
A1 - Garcés, G.
A1 - Bruno, Giovanni
T1 - Explaining Deviatoric Residual Stresses in Aluminum Matrix Composites with Complex Microstructure
N2 - The residual stresses in multiphase metal Matrix composites with both random planar-oriented short fibers and particles were studied by neutron diffraction and by a model based on the reformulation of classic Maxwell’s homogenization method. Contrary to common understanding and state-of-the-art models, we experimentally observed that randomly oriented phases possess non-hydrostatic residual stress. The recently developed modeling Approach allows calculating the residual stress in all phases of the composites. It rationalizes the presence of deviatoric stresses Accounting for the interaction of random oriented phases with fibers having preferential orientation.
KW - Metal matrix composite
KW - Residual stress
KW - Deviatoric
KW - Micromechanics
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506472
DO - https://doi.org/10.1007/s11661-020-05697-1
VL - 51
IS - 6
SP - 3104
EP - 3113
PB - Springer
AN - OPUS4-50647
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Villajos Collado, José Antonio
T1 - Experimental volumetric hydrogen uptake determination at 77 K of commercially available metal-organic framework materials
N2 - Storage is still limiting the implementation of hydrogen as an energy carrier to integrate the intermittent operation of renewable energy sources. Among different solutions to the currently used compressed or liquified hydrogen systems, physical adsorption at cryogenic temperature in porous materials is an attractive alternative due to its fast and reversible operation and the resulting reduction in storage pressure. The feasibility of cryoadsorption for hydrogen storage depends mainly on the performance of the used materials for the specific application, where metal-organic frameworks or MOFs are remarkable candidates. In this work, gravimetric and volumetric hydrogen uptakes at 77 K and up to 100 bar of commercially available MOFs were measured since these materials are made from relatively cheap and accessible building blocks. These materials also show relatively high porous properties and are currently near to large-scale production. The measuring device was calibrated at different room temperatures to calculate an average correction factor and standard deviation so that the correction deviation is included in the measurement error for better comparability with different measurements. The influence of measurement conditions was also studied, concluding that the available adsorbing area of material and the occupied volume of the sample are the most critical factors for a reproducible measurement, apart from the samples’ preparation before measurement. Finally, the actual volumetric storage density of the used powders was calculated by directly measuring their volume in the analysis cell, comparing that value with the maximum volumetric uptake considering the measured density of crystals. From this selection of commercial MOFs, the materials HKUST-1, PCN-250(Fe), MOF-177, and MOF-5 show true potential to fulfill a volumetric requirement of 40 g·L−1 on a material basis for hydrogen storage systems without further packing of the powders.
KW - Hydrogen adsorption
KW - Commercial metal-organic frameworks
KW - Hydrogen uptake reproducibility
KW - Volumetric uptake
KW - Packing density
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542215
DO - https://doi.org/10.3390/c8010005
SN - 2311-5629
VL - 8
IS - 1
SP - 1
EP - 14
PB - MDPI
CY - Basel
AN - OPUS4-54221
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zinke, R.
A1 - Virothi, N.
A1 - Köhler, F.
A1 - Klippel, A.
A1 - Schalau, Sebastian
A1 - Krause, U.
T1 - Experimental measurement of initial evaporation mass flows from gasoline spills and comparison with empirical models
N2 - In this paper, we investigate the evaporation mass flow originating from spills of gas-oline. Large spills of gasoline may form during partial or complete roof sinkings or inthe case of perforations at various deck fittings at external floating roof tanks usedfor the storage. Additionally, spills may form in the retention area in the case of leak-ages at pipes or at the hull. The aim is to predict the order of magnitude of real-scaleevaporation mass flow. The determined evaporation mass flows will be used in arelated project as input values for subsequent dispersion modeling in the vicinity ofthe tanks. This is relevant for questions of fire and explosion protection as well as forenvironmental protection aspects in tank farms or refineries, which use externalfloating roof tanks. The measurements presented in this paper were compared withpredictions by empirical models and investigations of evaporations from small floorspills, round-bottom flask, or from Petri dishes published in the literature. The maingoal of this paper is to test the applicability of empirical models to provide reasonableevaporation mass flows as input for CFD dispersion simulations.
KW - Spill evaporation
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504322
DO - https://doi.org/10.1002/prs.12128
VL - 39
IS - 3
SP - e12128
PB - Wiley Online Libary
AN - OPUS4-50432
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schaumann, P.
A1 - Schürmann, K.
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Experimental investigations on the fatigue resistance of automatically welded tubular X-joints for jacket support structures
N2 - The development within the offshore wind sector towards more powerful turbines combined with increasing water depth for new wind parks is challenging both the designer as well as the manufacturer of bottom fixed support structures. Besides XL-monopiles, the market developed an innovative and economic jacket support structure which is based on automatically manufactured tubular joints combined with standardized pipes. Besides the improvements for a serial manufacturing process the automatically welded tubular joints show a great potential in terms of fatigue resistance e.g. due to a smooth weld geometry without sharp notches. However, these benefits are not considered yet within the fatigue design process of automatically manufactured jacket substructures according to current standards due to the lack of suitable S-N curves. Therefore, 32 axial fatigue tests on single and double-sided automatically welded tubular X-joints have been performed to determine a new hot spot stress related S-N curve. Based on these constant amplitude fatigue tests a new S-N curve equal to a FAT 126 curve was computed which implicitly includes the benefits of the automatically welding procedure.
T2 - EERA Deep Wind 2020
CY - Trondheim, Norway
DA - 15.01.2020
KW - Notch stress approach
KW - Fatigue tests
KW - Automated manufacturing
KW - Tubular X-joints
KW - Structural stress approach
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-518509
DO - https://doi.org/10.1088/1742-6596/1669/1/012022
VL - 1669
SP - 012022
PB - IOP Publishing Ltd
AN - OPUS4-51850
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hirschberg, L.
A1 - Bake, Friedrich
A1 - Knobloch, K.
A1 - Hulshoff, S.
A1 - Hirschberg, A.
T1 - Experimental investigations of indirect noise due to modulation of axial vorticity and entropy upstream of a choked nozzle
N2 - An experimental cold-gas study of the response of a choked convergent–divergent nozzle to swirl perturbations is presented. The perturbations were obtained by means of upstream unsteady tangential injections into initially steady flows with different values of steady background swirl. The swirl perturbations induced changes in the axial mass-flow rate, due to either their ingestion or evacuation by the nozzle. This in turn caused a downstream acoustic response. For low-intensity background swirl the responses were found to be similar to those obtained without steady background swirl. Perturbations of a high-intensity background swirl led to different effects. For long injection times, the negative mass-flow rate modulation occurred in two stages. The first stage was similar to that of the background-swirl free case. The second stage occurred after a short time delay, and induced a much stronger negative acoustic response. This unexpected behavior suggests that a significant part of the tangentially injected fluid flows upstream inducing an accumulation of swirl, which is – after tangential injection is ceased – suddenly cleared out through the nozzle. A scaling rule for the amplitudes of these acoustic responses is reported. Furthermore, quasi-steady models, based on steady-state measurements are proposed. These models predict the downstream acoustic response amplitude within a factor two. Additionally, preliminary empirical evidence of the effect of swirl on the downstream acoustic response due to the interaction of entropy patches with a choked nozzle is reported. This was obtained by comparison of sound produced by abrupt radial or tangential sonic injection, upstream from the choked nozzle, of air from a reservoir at room temperature to that from a reservoir with a higher stagnation temperature. Because the mass flow through the nozzle does not increase instantaneously, the injected higher-enthalpy air accumulates upstream of the injection-port position in the main flow. This eventually induces a large downstream acoustic pulse when tangential injection is interrupted. The magnitude of the resulting sound pulse can reach that of a quasi-steady response of the nozzle to a large air patch with a uniform stagnation temperature equal to that of the upstream-injected heated air. This hypothesis is consistent with the fact that the initial indirect-sound pulse is identical to one obtained with unheated air injection. The authors posit that – given all of the insight gleaned from them in this case – acoustic measurements of indirect sound appear to be a potentially useful diagnostic tool.
KW - Aeroacoustics
KW - Indirect combustion noise
KW - Vorticity noise
KW - Entropy noise
KW - Swirl
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548331
DO - https://doi.org/10.1016/j.jsv.2022.116989
SN - 0022-460X
VL - 532
SP - 1
EP - 22
PB - Elsevier Ltd.
AN - OPUS4-54833
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
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 - Eberwein, Robert
A1 - Hajhariri, Aliasghar
A1 - Davide, Camplese
A1 - Giordano, Emrys Scarponi
A1 - Valerio, Cozzani
A1 - Frank, Otremba
T1 - Experimental investigation on the behavior of thermal super insulation materials for cryogenic storage tanks in fire incidents
N2 - The number of vehicles using or transporting cryogenic fuels such as Liquefied Hydrogen (LH2) or Liquefied Natural Gas (LNG) increases fast in the land transportation sector. Does this also entail new risks? The storage of cryogenic fuels requires tanks with Thermal Super Insulations (TSI) to keep the fluid cold and limit the formation of boil-off gas. TSI has proven itself in some applications since the middle of the 20th century, but in the land transport sector they are still quite new, where accidents involving fires, collisions, and their combination are to be expected. This work focuses on investigating the behavior of different types of TSI while exposed to a heat source representing a fire. To this aim, a High-Temperature Thermal Vacuum Chamber (HTTVC) was applied, which allows the thermal loading of a thermal insulation material in a vacuum and measuring the heat flow transported through the TSI in parallel. In this study, the results of 6 samples are presented regarding 3 types of MLI, rock wool, perlites, and microspheres. The thermal exposure caused different effects on the samples. In practice, this can be connected to the rapid release of flammable gases as well as to a Boiling Liquid Expanding Vapour Explosion (BLEVE). These results are relevant for reducing the risks to people and infrastructures in the progressive establishment of tanks for cryogenic fluids in our industry and society. The data presented in the study can be used to improve the design of tanks and TSIs, the assessment of accident scenarios, and the development of measures for first responders.
KW - Liquefied hydrogen
KW - Liquefied natural gas
KW - Tanks
KW - Fire
KW - Insulation
KW - MLI
KW - Perlite
KW - Rock wool
KW - Microspheres
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-599947
DO - https://doi.org/10.1016/j.psep.2024.04.131
SN - 0957-5820
VL - 187
SP - 240
EP - 248
PB - Elsevier
AN - OPUS4-59994
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Balscheit, Hagen
A1 - Victor, A.
A1 - Thiele, Marc
A1 - Cuéllar, Pablo
A1 - Baeßler, Matthias
A1 - Lüddecke, F.
T1 - Experimental Investigation on Buckling Behavior of soil-embedded Piles
N2 - Monopiles are currently the predominant foundation type for offshore wind turbines in Europe. Due to the increasing dimensions of the turbines, pile diameters beyond 10m become necessary. A design-relevant failure mode of monopiles is the local buckling of the pile wall in the embedded sections. Relevant buckling guidelines do not consider the soil-structure interaction specifically, although the embedment may allow for a reduction of wall thickness. However, Eurocode-based design concepts require a validation with comparative buckling cases for validation, either in terms of buckling curve parameters for both the algebraic stress-based and semi-numerical LBA/MNA design concept or as a calibration factor kGMNIA for fully numerical GMNIA calculations. These parameters are not yet available for embedded shells. To close this gap, we have conducted experiments on piles embedded in sand to investigate local buckling under soil-structure-interaction. The results will be used to calibrate numerical models. This research was carried out as part of the VERBATIM research project, funded by PTJ/BMWK and supported by the Carbon Trust's Offshore Wind Accelerator consortium.
T2 - EUROSTEEL 2023
CY - Amsterdam, The Netherlands
DA - 11.09.2023
KW - Wind
KW - Wind Energy
KW - Shell Buckling
KW - Offshore
KW - Soil-Structure-Interaction
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-583641
DO - https://doi.org/10.1002/cepa.2313
SN - 2509-7075
VL - 6
IS - 3-4
SP - 1729
EP - 1734
PB - Ernst & Sohn Gmb
AN - OPUS4-58364
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jiang, C.
A1 - Xie, G.
A1 - Wu, Dejian
A1 - Yan, T.
A1 - Chen, S.
A1 - Zhao, P.
A1 - Wu, Z.
A1 - Li, W.
T1 - Experimental investigation on an energy-efficient floor heating system with intelligent control: A case study in Chengdu, China
N2 - The space heating system accounts for 20%~50% of building energy consumption, and may lead to energy waste due to unreasonable controls. In this study, an energy-efficient floor heating system with intelligent control was proposed to improve energy efficiency of the system. In order to validate the concept of the proposed intelligent control, an experimental system was designed and constructed in Chengdu, China. Temperature, control cycle and energy consumption were then studied under different control strategies. The result shows that a larger flow rate of supply water will result in a longer control cycle and a lower control frequency, i.e., the average control cycle at 7 L min−1 is 1.7 h during the test day, while it is 1.5 h at 5 L min−1. Moreover, adopting water with a higher temperature and flow rate could achieve a higher efficiency of the system. The energy consumptions in case 1 (5 L min−1, 50 °C), case 2 (5 L min−1, 55 °C), case 5 (7 L min−1, 55 °C) and case 6 (7 L min−1, 60 °C) are 4746 kJ, 3534 kJ, 3093 kJ and 3028 kJ, respectively. Based on the experimental data, the supply water temperature is suggested to set lower than 60 °C considering human comfort.
KW - Floor heating
KW - Intelligent control
KW - Experimental
KW - Energy consumption
KW - Control strategy
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550522
DO - https://doi.org/10.1016/j.csite.2021.101094
SN - 2214-157X
VL - 26
SP - 1
EP - 14
PB - Elsevier Ltd.
AN - OPUS4-55052
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bernardy, Christopher
A1 - Habib, Abdel Karim
A1 - Kluge, Martin
A1 - Schalau, Bernd
A1 - Kant, Hanjo
A1 - Schulze, Marcel
A1 - Orchini, Alessandro
T1 - Experimental Investigation of Large-Scale Hydrogen Diffusion Jet Flames
N2 - Hydrogen is a promising alternative to natural gas in industrial energy applications to limit global warming. However, wide application of hydrogen requires specific safety considerations taking into account that hydrogen is stored and transported under much higher pressure than natural gas. Thus, one scenario to be considered for hazard assessment is a sudden release of hydrogen from a leakage or safety valve and its subsequent ignition. For hydrocarbon flames, various jet flame models are available. However, hydrogen flames significantly differ from hydrocarbon flames in their combustion behavior, so that the applicability of these models to hydrogen has to be investigated. For that purpose, reals scale tests were carried out at the BAM Test Site Technical Safety. In these tests, the flame geometry and the thermal heat radiation were investigated for a release angle of 90°, for different release pressures (up to 220 bar) and mass flows (up to 0.175 kg/s). Most existing data on thermal radiation are based on unsteady flow conditions and/or still air, whereas the experiments carried out here ensure a constant mass flow under realistic free-field conditions (with wind influence). This allows a better comparability with the stationary jet flame models and assessment of wind influence on model predictions. A number of parameters such as the surface emissive power and the radiant heat fraction were determined. A detailed comparison of the obtained experimental results with literature radiation models was performed. Based on the investigations, empirical equations for modelling jet flames could be derived.
T2 - Proceedings of ASME Turbo Expo 2025 Turbomachinery Technical Conference and Exposition
CY - Memphis, Tennessee, USA
DA - 16.06.2025
KW - Hydrogen release
KW - Radiant heat fraction
KW - Thermal radiation
KW - Jet flame
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-643401
DO - https://doi.org/10.1115/1.4070012
SN - 0742-4795
VL - 148
IS - 5
SP - 51008-1
EP - 51008-8
PB - ASME International
AN - OPUS4-64340
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Brunier-Coulin, F.
A1 - Sarrat, J.-L.
A1 - Cuéllar, Pablo
A1 - Philippe, P.
T1 - Experimental investigation of impinging jet erosion on model cohesive granular materials
N2 - Erosion of soils affects both natural landscapes and engineering constructions as embankment dams or levees. Improving the safety of such earthen structures requires in particular finding out more about the elementary mechanisms involved in soil erosion. Towards this end, an experimental work was undertaken in three steps. First, several model materials were developed, made of grains (mostly glass beads) with solid bridges at particle contacts whose mechanical yield strength can be continuously varied. Furthermore, for most of them, we succeeded in obtaining a translucent system for the purpose of direct visualization. Second, these materials were tested against surface erosion by an impinging jet to determine a critical shear stress and a kinetic coefficient. Note that an adapted device based on optical techniques (combination of Refractive Index Matching and Planar Laser Induced Fluorescence) was used specifically for the transparent media. Third, some specifically developed mechanical tests, and particularly traction tests, were implemented to estimate the mechanical strength of the solid bridges both at micro-scale (single contact) and at macro-scale (sample) and to investigate a supposed relationship with soil resistance to erosion.
T2 - 8th International Conference on Micromechanics on Granular Media
CY - Montpellier, France
DA - 03.07.2017
KW - Erosion onset
KW - Experimental testing
KW - Cohesive granular media
KW - RIM-PLIF techniques
PY - 2017
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411215
DO - https://doi.org/10.1051/epjconf/201714008002
VL - 140
SP - Paper 08002, 1
EP - Paper 08002, 4
PB - The European Physical Journal (EPJ) - Web of Conferences
AN - OPUS4-41121
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Fürst, Richard
A1 - Hejtmanek, P.
A1 - Vlach, T.
A1 - Repka, J.
A1 - Mozer, V.
A1 - Hajek, P.
T1 - Experimental Evaluation of Carbon Reinforced TRC with Cement Suspension Matrix at Elevated Temperature
N2 - Textile-reinforced concrete (TRC) is a new composite material comprising high-performance concrete and textile reinforcement from textile yarns with a matrix, usually consisting of epoxy resins (ER). The most significant advantage of ER is the homogenization of all filaments in the yarn and full utilization of its tensile potential. Nevertheless, ER matrix is a critical part of TRC design from the perspective of the fire resistance due to its relatively low resistance at temperatures of approximately 120 C. This work expands the previously performed mechanical tests at normal temperatures with cement suspension (CS) as a non-combustible material for the yarn matrix. Here, the mechanical properties of CS matrix at elevated temperatures were verified. It was found that the addition of polypropylene fibers into HPC negatively affected the mechanical results of CS matrix specimens. Simultaneously, thermal insulation effect of the covering layers with different thicknesses did not significantly influence the residual bending strength of specimens with CS matrix and achieved similar results as reference specimens. Furthermore, all specimens with ER matrix progressively collapsed. Finally, CS as a textile reinforcement of yarn matrix appears to be a suitable solution for increasing the temperature resistance of TRC structures and for substituting synthetic resins.
KW - Cement matrix
KW - Cement suspension
KW - Carbon fibers
KW - Textile reinforced concrete
KW - High-performance concrete
KW - Elevated temperature
KW - Fire safety
KW - Fire resistance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-550766
DO - https://doi.org/10.3390/polym14112174
SN - 2073-4360
VL - 14
IS - 11
SP - 1
EP - 16
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-55076
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Neubert, Sebastian
A1 - Pittner, Andreas
A1 - Rethmeier, Michael
T1 - Experimental determination of TRIP parameter K for mild- and high strength low alloy steels and a super martensitic filler material
N2 - A combined experimental numerical approach is applied to determine the transformation induced plasticity (TRIP)-parameter K for different strength low-alloy steels of grade S355J2+N and S960QL as well as the super martensitic filler CN13-4-IG containing 13 wt% chromium and 4 wt% nickel. The thermo-physical analyses were conducted using a Gleeble® 3500 facility. The thermal histories of the specimens to be tested were extracted from corresponding simulations of a real gas metal arc weldment. In contrast to common TRIP-experiments which are based on complex specimens a simple flat specimen was utilized together with an engineering evaluation method. The evaluation method was validated with literature values for the TRIP-parameter. It could be shown that the proposed approach enables a correct description of the TRIP behavior.
KW - Transformation induced plasticity (TRIP)
KW - Phase transformation
KW - High-strength low-alloy steel
KW - Super martensitic filler material
KW - Thermo physical simulation
KW - Gleeble experiments
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-367297
DO - https://doi.org/10.1186/s40064-016-2474-0
VL - 5
IS - 575
SP - Paper 754, 1
EP - 16
PB - SpringerPlus
AN - OPUS4-36729
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mohr, Gunther
A1 - Nowakowski, Susanna
A1 - Altenburg, Simon
A1 - Maierhofer, Christiane
A1 - Hilgenberg, Kai
T1 - Experimental Determination of the Emissivity of Powder Layers and Bulk Material in Laser Powder Bed Fusion Using Infrared Thermography and Thermocouples
N2 - Recording the temperature distribution of the layer under construction during laser powder bed fusion (L-PBF) is of utmost interest for a deep process understanding as well as for quality assurance and in situ monitoring means. While having a notable number of thermal monitoring approaches in additive manufacturing (AM), attempts at temperature calibration and emissivity determination are relatively rare. This study aims for the experimental temperature adjustment of an off-axis infrared (IR) thermography setup used for in situ thermal data acquisition in L-PBF processes. The temperature adjustment was conducted by means of the so-called contact method using thermocouples at two different surface conditions and two different materials: AISI 316L L-PBF bulk surface, AISI 316L powder surface, and IN718 powder surface. The apparent emissivity values for the particular setup were determined. For the first time, also corrected, closer to real emissivity values of the bulk or powder surface condition are published. In the temperature region from approximately 150 °C to 580 °C, the corrected emissivity was determined in a range from 0.2 to 0.25 for a 316L L-PBF bulk surface, in a range from 0.37 to 0.45 for 316L powder layer, and in a range from 0.37 to 0.4 for IN718 powder layer.
KW - Emisssivity
KW - Laser Powder Bed Fusion (L-PBF)
KW - Selective Laser Melting (SLM)
KW - Additive Manufacturing (AM)
KW - Process monitoring
KW - Infrared thermography
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516148
DO - https://doi.org/10.3390/met10111546
VL - 10
IS - 11
SP - 1546
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-51614
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Richter, Matthias
A1 - Schühle, Florian
T1 - Experimental determination of 7-day uptake rates for diffusive sampling of 86 volatile and semi-volatile organic compounds relevant for indoor air monitoring and investigation on their sensitivity to exposure time and indoor climate
N2 - This study aimed to experimentally determine uptake rates for 86 indoor relevant volatile and semi-volatile organic compounds (VOC, SVOC) for the passive sampler type Perkin Elmer/Markes™ with Tenax® TA as sorbent, which was used in the German Environmental Survey on Health (GerES VI) carried out by the German Environmental Agency (UBA) in the years 2023-2024. For this purpose, single reference gas atmospheres of 76 pure VOCs (liquid at room temperature) and a group of 10 SVOCs and VOCs (solid at room temperature) were generated using two generation procedures. By exposing the samplers to individual components, it was ruled out that interactions in a mixture have a influence on the uptake rate. Another aspect was to precisely describe the methodology and the resulting uncertainties, as there are gaps in the literature in this regard. The selection of the compounds was based on the findings of the preceding GerES V study for which data was missing or needed to be verified. In each experiment, a number of six passive samplers was exposed to the test gas atmospheres in dynamically operated exposure chambers for seven days. The sensitivity of the uptake rates of a group of 10 selected VOCs to variations in exposure time, ambient temperature, and air humidity in a multi-component reference gas atmosphere was investigated. Here, a decrease in the uptake rate with the exposure time could be observed stabilising from the fifth day of exposure onwards. A significant effect of temperature and humidity on the uptake rate was not apparent. The determined uptake rates exhibit uncertainties of < 20 % for 71 substances, and < 10 % for 51 substances which are also in good agreement with the literature, if already published elsewhere. The quantity of investigated substances, the detailed description of the methodology used to determine the uptake rates complemented by the respective uncertainties, as well as the compilation of comparative data, contribute to a better assessment of the quality and relevance of such data, which had not been published before.
KW - Indoor air quality
KW - Volatile organic compounds
KW - Uptake rates
KW - Passive sampling
KW - Tenax TA
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-629913
DO - https://doi.org/10.1016/j.indenv.2025.100095
VL - 2
IS - 2
SP - 1
EP - 11
PB - Elsevier
AN - OPUS4-62991
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Sonntag, Nadja
A1 - Jürgens, Maria
A1 - Uhlemann, Patrick
A1 - Skrotzki, Birgit
A1 - Olbricht, Jürgen
T1 - Experimental data from service-like creep-fatigue experiments on grade P92 steel
N2 - This article refers to the research article entitled “Creep-Fatigue of P92 in Service-Like Tests with Combined Stress- and Strain-Controlled Dwell Times” [1]. It presents experimental mechanical data from complex service-like creep-fatigue experiments performed isothermally at 620 °C and a low strain amplitude of 0.2 % on tempered martensite-ferritic grade P92 steel. The data sets in text file format provide cyclic deformation (min. and max. stresses) and the total (hysteresis) data of all recorded fatigue cycles for three different creep-fatigue experiments: 1) a standard relaxation fatigue (RF) test with symmetrical dwell times of three minutes introduced at minimum and maximum strain, 2) a fully strain-controlled service-like relaxation (SLR) test combining these three-minute peak strain dwells with a 30-minute dwell in between at zero strain, and 3) a partly stress-controlled service-like creep (SLC) test combining the three-minute peak strain dwells with 30-minute dwells at constant stress. Such service-like (SL) tests with additional long-term stress- and strain-controlled dwell times are non-standard, rare, and expensive, making these data very valuable. They may be used to approximate cyclic softening in the technically relevant range, for the design of complex SL experiments, or for detailed analyses of stress-strain hystereses (e.g., for stress or strain partitioning methods, for the determination of hysteresis energies (work), inelastic strain components, etc.). In addition, the latter analyses may supply important input for advanced parametric lifetime modeling of components under creep-fatigue loading or model calibration parameters.
KW - Tempered martensite-ferritic steel
KW - Creep
KW - Stress relaxation
KW - Creep-fatigue
KW - Dwell times
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-578407
DO - https://doi.org/10.1016/j.dib.2023.109333
SN - 2352-3409
VL - 49
SP - 1
EP - 9
PB - Elsevier Inc.
AN - OPUS4-57840
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zou, T.
A1 - Nonappa, N.
A1 - Khavani, M.
A1 - Vuorte, M.
A1 - Penttilä, P.
A1 - Zitting, A.
A1 - Valle-Delgado, J. J.
A1 - Elert, Anna Maria
A1 - Silbernagl, Dorothee
A1 - Balakshin, M.
A1 - Sammalkorpi, M.
A1 - Österberg, M.
T1 - Experimental and Simulation Study of the Solvent Effects on the Intrinsic Properties of Spherical Lignin Nanoparticles
N2 - Spherical lignin nanoparticles (LNPs) fabricated via nanoprecipitation of dissolved lignin are among the most attractive biomass-derived nanomaterials. Despite various studies exploring the methods to improve the uniformity of LNPs or seeking more application opportunities for LNPs, little attention has been given to the fundamental aspects of the solvent effects on the intrinsic properties of LNPs. In this study, we employed a variety of experimental techniques and molecular dynamics (MD) simulations to investigate the solvent effects on the intrinsic properties of LNPs. The LNPs were prepared from softwood Kraft lignin (SKL) using the binary solvents of aqueous acetone or aqueous tetrahydrofuran (THF) via nanoprecipitation. The internal morphology, porosity, and mechanical properties of the LNPs were analyzed with electron tomography (ET), small-angle X-ray scattering (SAXS), atomic force microscopy (AFM), and intermodulation AFM (ImAFM). We found that aqueous acetone resulted in smaller LNPs with higher uniformity compared to aqueous THF, mainly ascribing to stronger solvent−lignin interactions as suggested by MD simulation results and confirmed with aqueous 1,4-dioxane (DXN) and aqueous dimethyl sulfoxide (DMSO).
More importantly, we report that both LNPs were compact particles with relatively homogeneous density distribution and very low porosity in the internal structure. The stiffness of the particles was independent of the size, and the Young’s modulus was in the range of 0.3−4 GPa. Overall, the fundamental understandings of LNPs gained in this study are essential for the design of LNPs with optimal performance in applications.
KW - Lignin
KW - Electron tomography
KW - Intermodulation AFM
KW - Modulus
KW - SAXS
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-546948
DO - https://doi.org/10.1021/acs.jpcb.1c05319
SN - 1520-5207
VL - 125
IS - 44
SP - 12315
EP - 12328
PB - ACS
AN - OPUS4-54694
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - El Harrab, Hayat
A1 - Askar, Enis
A1 - Franken, T.
A1 - Mauss, F.
T1 - Experimental and reaction kinetic study of hydrogen ignition behavior at ignition limits
N2 - The paper presents the results of an experimental and reaction kinetic investigation of hydrogen ignition at different pressures in a closed vessel, highlighting its non-linear behavior and the effects of radical wall termination. The reaction kinetic simulation predicts the three characteristic ignition limits of hydrogen caused by radical and thermal auto-ignition and is in close agreement with the experimental measurements. The first ignition limit is determined by the chain branching reaction H+O_2→O+ OH. This limit shows strong sensitivity towards the wall termination of O, H and OH radicals. The second ignition limit is influenced by the wall termination of O, H, OH, HO2 and H2O2 radicals. The third ignition limit is dominated by the reaction paths HO_2+HO_2→H_2 O_2+O_2 and H_2 O_2+M→2 OH+M, which is why it shows strong sensitivity towards wall termination of HO₂ and H₂O₂ radicals. Increasing the radical wall termination rate by increasing the sticking coefficient of the radicals at the wall or the surface-to-volume-ratio leads to an increase of the auto-ignition temperature at the same pressure. The introduction of radical wall termination reactions improved the prediction of ignition limits and highlighted the profound effect of the autoclave wall and vessel size on the hydrogen ignition behavior.
KW - Radical Wall Termination Reaction
KW - Hydrogen
KW - Auto-ignition Temperature
KW - Ignition Limit
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-647609
DO - https://doi.org/10.1016/j.proci.2025.105980
SN - 1540-7489
VL - 41
SP - 1
EP - 7
PB - Elsevier Inc.
AN - OPUS4-64760
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Yang, Chunliang
A1 - Yang, Fan
A1 - Meng, Xiangmeng
A1 - Putra, Stephen Nugraha
A1 - Bachmann, Marcel
A1 - Rethmeier, Michael
T1 - Experimental and numerical study on grain refinement in electromagnetic assisted laser beam welding of 5754 Al alloy
N2 - Through experimental observation and auxiliary numerical simulation, this investigation studies the different types of grain refinement of 5754 aluminum alloy laser beam welding by applying a transverse oscillating magnetic field. Scanning electron microscope results have proved that the application of a magnetic field can reduce the average crystal branch width and increase its number. The interaction between the induced eddy current generated by the Seebeck effect and the applied external magnetic field produces a Lorentz force, which is important for the increase in the number of crystal branches. Based on the theory of dendrite fragmentation and the magnetic field-induced branches increment, the grain size reduction caused by the magnetic field is studied. Furthermore, the effects of the magnetic field are analyzed by combining a phase field method model and simulations of nucleation and grain growth. The grain distribution and average grain
size after welding verify the reliability of the model. In addition, the introduction of a magnetic field can increase the number of periodic three-dimensional solidification patterns. In the intersection of two periods of solidification patterns, the metal can be re-melted and then re-solidified, which prevents the grains, that have been solidified and formed previously, from further growth and generates some small cellular grains in the new fusion line. The magnetic field increases the building frequency of these solidification structures and thus promotes this kind of grain refinement.
KW - Laser beam welding
KW - Magnetic field
KW - Crystal branch development
KW - Grain refinement
KW - Periodic solidification pattern
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584905
DO - https://doi.org/10.2351/7.0001085
SN - 1042-346X
VL - 35
IS - 4
SP - 1
EP - 10
PB - AIP Publishing
AN - OPUS4-58490
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Avilov, Vjaceslav
A1 - Gumenyuk, Andrey
A1 - Rethmeier, Michael
T1 - Experimental and numerical investigation of an electromagnetic weld pool control for laser beam welding
N2 - The objective of this study was to investigate the influence of externally applied magnetic fields on the weld quality in laser beam welding. The optimization of the process parameters was performed using the results of computer simulations. Welding tests were performed with up to 20 kW laser beam power. It was shown that the AC magnet with 3 kW power supply allows for a prevention of the gravity drop-out for full penetration welding of 20 mm thick stainless steel plates. For partial penetration welding it was shown that an0.5 T DC magnetic field is enough for a suppression of convective flows in the weld pool. Partial penetration welding tests with 4 kW beam power showed that the application of AC magnetic fields can reduce weld porosity by a factor of 10 compared to the reference joints. The weld surface roughness was improved by 50%.
KW - Laser beam welding
KW - Electromagnetic weld pool support
KW - Hartmann effect
KW - Electromagnetic rectification
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-314405
DO - https://doi.org/10.1016/j.phpro.2014.08.006
SN - 1875-3892
VL - 56
SP - 515
EP - 524
PB - Elsevier B.V.
CY - Amsterdam [u.a.]
AN - OPUS4-31440
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Chaudry, Mohsin Ali
A1 - Mohr, Gunther
A1 - Hilgenberg, Kai
T1 - Experimental and numerical comparison of heat accumulation during laser powder bed fusion of 316L stainless steel
N2 - Heat accumulation during laser powder bed fusion (LPBF) of metallic build parts can adversely affect their microstructure and mechanical properties. To study the heat accumulation during 316L steel based parts manufactured by LPBF, a finite element method (FEM) based numerical study is carried out. For the investigation, a computationally efficient FEM based model, where the whole layer is simultaneously exposed to a heat source, is used. The simulation results are compared with experimental results to validate the numerical model. While considering different influencing factors such as volumetric energy density (VED) and inter-layer time (ILT), the FEM model is shown to successfully simulate the process of heat accumulation during LPBF based manufacturing of a cuboidal shaped geometry. It is shown that ILT and VED have a significant effect on heat accumulation. The validated numerical model provides a good basis for the optimization of processing parameters and geometries for a future investigation of a reduction of heat accumulation effects. Furthermore, it can be used to quickly provide preheating boundary conditions for detailed investigations by different model approaches at a finer scale for future studies.
KW - Laser powder bed fusion
KW - Finite element method
KW - Heat accumulation
KW - Inter-layer time
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-545115
DO - https://doi.org/10.1007/s40964-022-00282-x
SP - 1
EP - 13
PB - Springer
AN - OPUS4-54511
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Liehr, A.
A1 - Wegener, T.
A1 - Degener, Sebastian
A1 - Bolender, A.
A1 - Möller, N.
A1 - Niendorf, T.
T1 - Experimental Analysis of the Stability of Retained Austenite in a Low‐Alloy 42CrSi Steel after Different Quenching and Partitioning Heat Treatments
N2 - Quenching and partitioning (Q&P) steels are characterized by an excellent combination of strength and ductility, opening up great potentials for advanced lightweight components. The Q&P treatment results in microstructures with a martensitic matrix being responsible for increased strength whereas interstitially enriched metastable retained austenite (RA) contributes to excellent ductility. Herein, a comprehensive experimental characterization of microstructure evolution and austenite stability is carried out on a 42CrSi steel being subjected to different Q&P treatments. The microstructure of both conditions is characterized by scanning electron microscopy as well as X‐ray diffraction (XRD) phase analysis. Besides macroscopic standard tensile tests, RA evolution under tensile loading is investigated by in situ XRD using synchrotron and laboratory methods. As a result of different quenching temperatures, the two conditions considered are characterized by different RA contents and morphologies, resulting in different strain hardening behaviors as well as strength and ductility values under tensile loading. In situ synchrotron measurements show differences in the transformation kinetics being rationalized by the different morphologies of the RA. Eventually, the evolution of the phase specific stresses can be explained by the well‐known Masing model.
KW - Condensed Matter Physics
KW - General Materials Science
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-581618
DO - https://doi.org/10.1002/adem.202300380
SN - 1438-1656
VL - 25
IS - 17
SP - 1
EP - 16
PB - Wiley
AN - OPUS4-58161
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bühling, Benjamin
A1 - Strangfeld, Christoph
A1 - Maack, Stefan
A1 - Schweitzer, T.
T1 - Experimental analysis of the acoustic field of an ultrasonic pulse induced by a fluidic switch
N2 - Ultrasonic inspection is a common tool for non-destructive testing in civil engineering (NDT-CE). Currently, transducers are coupled directly to the specimen surface, which makes the inspection time-consuming. Air-coupled ultrasound (ACU) transducers are more time-efficient but need a high pressure amplitude as the impedance mismatch between the air and the concrete is high and large penetration depth is needed for the inspection. Current approaches aim at eliminating the impedance mismatch between the transducer and the air to gain amplitude; however, they hardly fulfill the NDT-CE requirements. In this study, an alternative approach for ultrasound generation is presented: the signal is generated by a fluidic switch that rapidly injects a mass flow into the ambience. The acoustic field, the flow field, and their interaction are investigated. It is shown that the signal has dominant frequencies in the range of 35–60 kHz, and the amplitude is comparable to that of a commercial ACU transducer.
KW - Air-coupled ultrasound
KW - Non-destructive testing
KW - Ultrasonic transducer
KW - Acoustic-flow interaction
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523862
DO - https://doi.org/10.1121/10.0003937
VL - 149
IS - 4
SP - 2150
EP - 2158
AN - OPUS4-52386
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Klippel, Andrea
A1 - Hofmann‐Böllinghaus, Anja
A1 - Piechnik, Kira
A1 - Heydick, Lukas
A1 - Wu, Hongyi
A1 - Köhler, Florian
A1 - Klaffke, Benjamin
T1 - Experimental Analysis of Fire Behavior in Pine Forests and Agricultural Fields: Large‐Scale Tests Conducted Within the European TREEADS Project
N2 - Two large‐scale experiments investigated fire spread mechanisms in vegetation ground fires in a pine forest and an agricultural field within the European TREEADS project. The tests, conducted in Saxony‐Anhalt and Brandenburg, targeted regions with dry, sandy soils and extensive pine stands and aim to improve suppression strategies and wildfire research. The forest experiment was conducted on a 16 × 22 m plot with line ignition using a gasoline‐diesel mix. Fire spread was documented with drone‐based video and infrared imaging. Ninety‐six thermocouples and two gas sensors were mounted on trees, and a mobile FTIR spectrometer enabled real‐time smoke analysis. A tilled and foam‐treated strip prevented uncontrolled spread. Under stable weather conditions (23°C, light wind, low soil moisture), a consistent temperature rise and distinct combustion phases were observed. Smoldering dominated in areas with mosses, grasses, and deadwood, with intermittent flaming, limited flame heights (< 0.5 m), and substantial smoke production. Peak temperatures exceeded 500°C, and CO concentrations reached 238 ppm, though wind turbulence complicated gas sampling. The second experiment on a cut agricultural field near Nauen involved burning approximately 700 m2 using a 20 m ignition line aligned with wind direction. Drone‐based infrared monitoring captured rapid spread on the stubble surface. The results underscore the variability and measurement challenges of outdoor fires and highlight the necessity of continued large‐scale experiments to support physical and numerical wildfire modeling. These findings provide essential empirical data for evaluating vegetation‐specific burning behavior, improving sensor deployment strategies, and refining validation approaches for next‐generation wildfire spread models under central European fuel and weather conditions, and supporting decision‐making in wildfire management.
KW - Wildfire
KW - Pine
KW - Crop
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654199
DO - https://doi.org/10.1002/fam.70045
SN - 0308-0501
SP - 1
EP - 11
PB - Wiley
AN - OPUS4-65419
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Tavernaro, Isabella
A1 - Sander, P. C.
A1 - Andresen, Elina
A1 - Schedler, U.
A1 - Resch-Genger, Ute
T1 - Expanding the Toolbox of Simple, Cost-Efficient, and Automatable Methods for Quantifying Surface Functional Groups on Nanoparticles� Potentiometric Titration
N2 - Measuring surface functional groups (FGs) on nanomaterials (NMs) is essential for designing dispersible and stable NMs with tailored and predictable functionality. FG screening and quantification also plays a critical role for subsequent processing steps, NM long-term stability, quality control of NM production, and risk assessment studies and enables the implementation of sustainable and safe(r)-by-design concepts. This calls for simple and cost-efficient methods for broadly utilized FGs that can be ideally automated to speed up FG screening, monitoring, and quantification. To expand our NM surface analysis toolbox, focusing on simple methods and broadly available, cost-efficient instrumentation, we explored a NM-adapted pH titration method with potentiometric and optical readout for measuring the total number of (de)protonable FGs on representatively chosen commercial and custom-made aminated silica nanoparticles (SiO2 NPs). The accuracy and robustness of our stepwise optimized workflows was assessed by several operators in two laboratories and method validation was done by cross-comparison with two analytical methods relying on different signal generation principles. This included traceable, chemo-selective quantitative nuclear magnetic resonance spectroscopy (qNMR) and thermogravimetric analysis (TGA), providing the amounts of amino silanes released by particle dissolution and the total mass of the surface coatings. A comparison of the potentiometric titration results with the reporter-specific amounts of surface amino FGs determined with the previously automated fluorescamine (Fluram) assay highlights the importance of determining both quantities for surface-functionalized NMs. In the future, combined NM surface analysis with optical assays and pH titration will simplify quality control of NM production processes and stability studies and can yield large data sets for NM grouping that facilitates further developments in regulation and standardization.
KW - Quality assurance
KW - Fluorescence
KW - Nano
KW - Particle
KW - Synthesis
KW - Characterization
KW - Advanced material
KW - Surface
KW - Standardization
KW - Reference material
KW - Functional group
KW - Quantification
KW - Coating
KW - Automation
KW - Potentiometry
KW - Method
KW - Validation
KW - Optical assay
KW - Fluram
KW - Fluorescamine
KW - qNMR
KW - Comparison
KW - ILC
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642371
DO - https://doi.org/10.1021/acsmeasuresciau.5c00062
SN - 2694-250X
SP - 1
EP - 13
PB - American Chemical Society
CY - Washington, DC
AN - OPUS4-64237
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Cabo Rios, Alberto
A1 - Mishurova, Tatiana
A1 - Cordova, Laura
A1 - Persson, Mats
A1 - Bruno, Giovanni
A1 - Olevsky, Eugene
A1 - Hryha, Eduard
T1 - Ex-situ characterization and simulation of density fluctuations evolution during sintering of binder jetted 316L
N2 - Efficient density evolution during sintering of the as-printed component is vital to reach full densification and required properties of binder jet (BJT) components. However, due to the high porosity and brittle nature of the green compact, analysis of the microstructure development during sintering is very difficult, resulting in lack of understanding of the densification process. Density development from green state (57 ± 1.6 %) up to full density (99 ± 0.3 %) was characterized by high-resolution synchrotron X-Ray computed tomography (SXCT) on BJT 316L samples from ex-situ interrupted sintering tests. Periodicity of density fluctuations along the building direction was revealed for the first time and was related to the layer thickness of ~ 42 μm during printing that decreased down to ~ 33 μm during sintering. Sintering simulations, utilizing a continuum sintering model developed for BJT, allowed to replicate the density evolution during sintering with a mean error of 2 % and its fluctuation evolution from green (1.66 %) to sintered (0.56 %) state. Additionally, simulation of extreme particle size segregation (1 μm to 130 μm) suggested that non-optimized printing could lead to undesirable density fluctuation amplitude rapid increase (~10 %) during sintering. This might trigger the nucleation of defects (e.g., layer delamination, cracking, or excessive residual porosity) during the sintering process.
KW - Additive manufacturing
KW - Synchrotron X-ray CT
KW - Binder Jetting
KW - Sintering
KW - FEM Simulation
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594389
DO - https://doi.org/10.1016/j.matdes.2024.112690
SN - 0264-1275
VL - 238
SP - 1
EP - 18
PB - Elsevier
AN - OPUS4-59438
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Wipfler, B.
A1 - Bradler, S.
A1 - Büsse, S.
A1 - Hammel, J.
A1 - Müller, Bernd R.
A1 - Pass, G.
T1 - Evolutionary morphology of the antennal heart in stick and leaf insects (Phasmatodea) and webspinners (Embioptera) (Insecta: Eukinolabia)
N2 - The morphology of the antennal hearts in the head of Phasmatodea and Embioptera was investigated with particular reference to phylogenetically relevant key taxa. The antennal circulatory organs of all examined species have the same basic construction: they consist of antennal vessels that are connected to ampullae located in the head near the antenna base. The ampullae are pulsatile due to associated muscles, but the points of attachment differ between the species studied. All examined Phasmatodea species have a Musculus (M.) interampullaris which extends between the two ampullae plus a M. ampulloaorticus that runs from the ampullae to the anterior end of the aorta; upon contraction, all these muscles dilate the lumina of both ampullae at the same time. In Embioptera, only the australembiid Metoligotoma has an M. interampullaris. All other studied webspinners instead have a M. ampullofrontalis which extends between the ampullae and the frontal region of the head capsule; these species do not have M. ampulloaorticus. Outgroup comparison indicates that an antennal heart with a M. interampullaris is the plesiomorphic character state among Embioptera and the likely ground pattern of the taxon Eukinolabia. Antennal hearts with a M. ampullofrontalis represent a derived condition that occurs among insects only in some embiopterans. These findings help to further clarify the controversially discussed internal phylogeny of webspinners by supporting the view that Australembiidae are the sister group of the remaining Embioptera.
KW - Phylogeny
KW - Polyneoptera
KW - Metoligotoma
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-527795
DO - https://doi.org/10.1007/s00435-021-00526-4
SN - 1432-234X
VL - 140
IS - 3
SP - 331
EP - 340
PB - Springer
AN - OPUS4-52779
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Laquai, René
A1 - Gouraud, F.
A1 - Müller, Bernd R.
A1 - Huger, M.
A1 - Chotard, T.
A1 - Antou, G.
A1 - Bruno, Giovanni
T1 - Evolution of Thermal Microcracking in Refractory ZrO2-SiO2 after Application of External Loads at High Temperatures
N2 - Zirconia-based cast refractories are widely used for glass furnace applications. Since they have to withstand harsh chemical as well as thermo-mechanical environments, internal stresses and microcracking are often present in such materials under operating conditions (sometimes in excess of 1700 °C). We studied the evolution of thermal (CTE) and mechanical (Young’s modulus) properties as a function of temperature in a fused-cast refractory containing 94 wt.% of monoclinic ZrO2 and 6 wt.% of a silicate glassy phase. With the aid of X-ray refraction techniques (yielding the internal specific surface in materials), we also monitored the evolution of microcracking as a function of thermal cycles (crossing the martensitic phase transformation around 1000 °C) under externally applied stress. We found that external compressive stress leads to a strong decrease of the internal surface per unit volume, but a tensile load has a similar (though not so strong) effect. In agreement with existing literature on -eucryptite microcracked ceramics, we could explain These phenomena by microcrack closure in the load direction in the compression case, and by microcrack propagation (rather than microcrack nucleation) under tensile conditions.
KW - Electro-fused zirconia
KW - Microcracking
KW - Synchrotron x-ray refraction radiography (SXRR)
KW - Thermal expansion
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-477431
DO - https://doi.org/10.3390/ma12071017
VL - 12
IS - 7
SP - 1
EP - 15
PB - MDPI
AN - OPUS4-47743
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Roveda, Ilaria
A1 - Mishurova, Tatiana
A1 - Evans, Alexander
A1 - Fitch, Andrew N.
A1 - Haubrich, Jan
A1 - Requena, Guillermo
A1 - Bruno, Giovanni
A1 - Serrano-Munoz, Itziar
T1 - Evolution of interphase stress over a crack propagation plane as a function of stress relief heat treatments in a PBF‐LB/M AlSi10Mg alloy
N2 - AbstractIn this study, we compare the residual stress state in a laser powder bed fusion (PBF‐LB/M) AlSi10Mg alloy in the as‐built (AB) condition with that after two different heat treatments (265 °C for 1 h, HT1; and 300 °C for 2 h, HT2). The bulk residual stress (RS) is determined using synchrotron X‐ray diffraction (SXRD), and near‐surface profiles are determined using laboratory energy‐dispersive X‐ray diffraction (EDXRD). The EDXRD results do not reveal any notable difference between the conditions at a depth of 350 μm, suggesting that the machining process yields a comparable residual stress state in the near‐surface regions. On the other hand, the SXRD results show that HT1 is more effective in relieving the bulk RS. It is observed that HT1 reduces the RS state in both the aluminium matrix and the silicon network. In addtion, HT2 does not have a significant impact on relaxing the RS as‐built state of the matrix, although it does induce a reduction in the RS magnitudes of the Si phase. It is concluded that the heat treatment stress relieving is effective as long as the Si‐network is not disaggregated.
KW - Interphase residual stress
KW - Laboratory energy-dispersive X-ray diffraction (EDXRD)
KW - PBFLB/M AlSi10Mg alloy
KW - Stress-relief heat-treatments
KW - Synchrotron X-ray diffraction (SXRD)
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597591
DO - https://doi.org/10.1111/str.12475
VL - 60
IS - 6
SP - 1
EP - 13
PB - John Wiley & Sons Ltd.
AN - OPUS4-59759
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Laquai, René
A1 - Müller, Bernd R.
A1 - Paciornik, S.
A1 - Horvath, J.
A1 - Tushtev, K.
A1 - Rezwan, K.
A1 - Bruno, Giovanni
T1 - Evolution of Damage in All-Oxide Ceramic Matrix Composite After Cyclic Loading
N2 - While structural ceramics usually display a brittle mechanical behavior, their composites may show nonlinearities, mostly due to microcracking. Herein, the stiffness evolution of a sandwich-like laminate of an Al2O3 15%vol. ZrO2 matrix reinforced with Nextel 610 fibers is studied as a function of number of cycles N in tension. The stiffness of the composite degrades with increasing N, indicating microcracking. However, synchrotron X-ray refraction radiography shows that the internal specific surface of such cracks varies differently. A modeling strategy is developed for the calculation of the equivalent stiffness of mixtures (first the matrix and then the sandwich), based on the Voigt and Reuß schemes. The Bruno–Kachanov model is then used to estimate the initial microcrack density in the matrix (due to the thermal expansion mismatch) and the amount of microcracking increase upon cyclic loading. The stiffness in the composite degrades dramatically already after 20 000 cycles but then remains nearly constant. The combination of mechanical testing, quantitative imaging analysis, and modeling provides insights into the damage mechanisms acting: microcrack propagation is more active than microcrack initiation upon cyclic loading, but the second also occurs. This scenario is similar but not equal to previous results on porous and microcracked ceramics.
KW - Ceramic matrix composites
KW - Homogenization schemes
KW - Microcracking
KW - Nonlinear behavior
KW - Synchrotron X-ray refraction radiography
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534541
DO - https://doi.org/10.1002/adem.202100763
SN - 1527-2648
SN - 1438-1656
VL - 24
IS - 6
SP - 2100763 -1
EP - 2100763 -13
PB - VCH GmbH
CY - Weinheim
AN - OPUS4-53454
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Ulbricht, Alexander
A1 - Ávila Calderón, Luis
A1 - Sommer, Konstantin
A1 - Mohr, Gunther
A1 - Evans, Alexander
A1 - Skrotzki, Birgit
A1 - Bruno, Giovanni
T1 - Evolution of Creep Damage of 316L Produced by Laser Powder Bed Fusion
N2 - The damage mechanisms of metallic components produced by process laser powder bed fusion differ significantly from those typically observed in conventionally manufactured variants of the same alloy. This is due to the unique microstructures of additively manufactured materials. Herein, the focus is on the study of the evolution of creep damage in stainless steel 316L specimens produced by laser powder bed fusion. X-ray computed tomography is used to unravel the influence of the process-specific microstructure from the influence of the initial void distribution on creep damage mechanisms. The void distribution of two specimens tested at 600 °C and 650 °C is analyzed before a creep test, after an interruption, and after fracture. The results indicate that the formation of damage is not connected to the initial void distribution. Instead, damage accumulation at grain boundaries resulting from intergranular cracking is observed.
KW - Creep
KW - Computed Tomography
KW - PBF-LB/M/316L
KW - Laser Powder Bed Fusion
KW - Microstructure
KW - AISI 316L
KW - Additive Manufacturing
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-574127
DO - https://doi.org/10.1002/adem.202201581
SP - 1
EP - 9
PB - Wiley-VCH GmbH
CY - Weinheim
AN - OPUS4-57412
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Kupsch, Andreas
A1 - Trappe, Volker
A1 - Müller, Bernd R.
A1 - Bruno, Giovanni
T1 - Evolution of CFRP stress cracks observed by in situ X-ray refractive imaging
N2 - Modern air-liners and wind turbine rotor blades are made up primarily of fiber reinforced plastics. Failure of these materials heavily impairs the serviceability and the operational safety. Consequently, knowledge of the failure behavior under static and cyclic loads is of great interest to estimate the operational strength and to compare the performance of different materials. Ideally, the damage evolution under operational load is determined with in situ non-destructive testing techniques. Here, we report in-situ synchrotron X-ray imaging of tensile stress induced cracks in carbon fiber reinforced plastics due to inter-fiber failure. An inhouse designed compact tensile testing machine with a load range up to 15 kN was integrated into the beamline. Since conventional radiographs do not reveal sufficient contrast to distinguish cracks due to inter-fiber failure and micro cracking from fiber bundles, the Diffraction Enhanced Imaging (DEI) technique is applied in order to separate primary and scattered (refracted) radiation by means of an analyzer crystal. This technique allows fast measurements over large fields-of-view and is ideal for in-situ investigations. Imaging and the tensile test are run at the highest possible frame rate (0.7 s-1 ) and the lowest possible strain rate (5.5∙10-4 s -1 ). For 0°/90° non-crimp fabrics, the first inter-fiber cracks occur at 380 MPa (strain 0.8 %). Prior to failure at about 760 MPa (strain 2.0 %), we observe the evolution of nearly equidistant (1 mm distance) cracks running across the entire sample in the fully damaged state.
KW - X-ray refraction
KW - Diffraction Enhanced Imaging
KW - Carbon Fiber Reinforced Plastics
KW - In situ tensile test
KW - Crack evolution
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-515060
DO - https://doi.org/10.1088/1757-899X/942/1/012035
SN - 1757-8981
SN - 1757-899X
VL - 942
SP - 012035-1
EP - 012035-9
PB - IOP publishing
CY - Bristol, UK
AN - OPUS4-51506
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Pech May, Nelson Wilbur
A1 - Tabasco-Novelo, Carolina
A1 - Quintana, Patricia
A1 - Rodriguez-Gattorno, Geonel
A1 - Alvarado-Gil, Juan J.
T1 - Evidence of a Thermal Diffusivity Gap in Sintered Li–Co–Sb–O Solid Solutions
N2 - In this work, the thermal properties of ternary Li₃ₓCo₇₋₄ₓSb₂₊ₓO₁₂ solid solutions are studied for different concentrations in the range 0 ≤ x ≤ 0.7. Samples are elaborated at four different sintering temperatures: 1100, 1150, 1200 and 1250 °C. The effect of increasing the content of Li⁺ and Sb⁵⁺, accompanied by the reduction of Co²⁺, on the thermal properties is studied. It is shown that a thermal diffusivity gap, which is more pronounced for low values of x, can be triggered at a certain threshold sintering temperature (around 1150 °C in this study). This effect is explained by the increase of contact area between adjacent grains. Nevertheless, this effect is found to be less pronounced in the thermal conductivity. Moreover, a new framework for heat diffusion in solids is presented that establishes that both the heat flux and the thermal energy (or heat) satisfy a diffusion equation and therefore highlights the importance of thermal diffusivity in transient heat conduction phenomena.
KW - General Chemical Engineering
KW - General Chemistry
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593248
DO - https://doi.org/10.1021/acsomega.2c07557
SN - 2470-1343
VL - 8
IS - 8
SP - 7808
EP - 7815
PB - American Chemical Society (ACS)
CY - Washington, DC
AN - OPUS4-59324
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dorgerloh, Ute
A1 - Becker, Roland
A1 - Kaiser, M.
T1 - Evidence for the formation of difluoroacetic acid in chlorofluorocarbon-contaminated ground water
N2 - The concentrations of difluoroacetic acid (DFA) and trifluoroacetic acid (TFA) in rainwater and surface water from Berlin, Germany resembled those reported for similar urban areas, and the TFA/DFA ratio in rainwater of 10:1 was in accordance with the literature. In contrast, nearby ground water historically contaminated with 1,1,2-trichloro-1,2,2-trifluoroethane (R113) displayed a TFA/DFA ratio of 1:3. This observation is discussed versus the inventory of microbial Degradation products present in this ground water along with the parent R113 itself. A microbial Transformation of chlorotrifluoroethylene (R1113) to DFA so far has not been reported for environmental media, and is suggested based on well-established mammalian metabolic pathways.
KW - Fluoroacetic acid
KW - DFA
KW - TFA
KW - Rainwater
KW - Ground water
KW - Degradation of refrigerants
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-475569
DO - https://doi.org/10.3390/molecules24061039
SN - 1420-3049
VL - 24
IS - 6
SP - 1039, 1
EP - 6
PB - MDPI
CY - Basel
AN - OPUS4-47556
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - He, Shulin
A1 - Sieksmeyer, Thorben
A1 - Che, Y.
A1 - Mora, M. A. E.
A1 - Stiblik, P.
A1 - Banasiak, Ronald
A1 - Harrison, M. C.
A1 - Sobotnik, J.
A1 - Wang, Z.
A1 - Johnston, P. R.
A1 - McMahon, Dino Peter
T1 - Evidence for reduced immune gene diversity and activity during the evolution of termites
N2 - The evolution of biological complexity is associated with the emergence of bespoke immune systems that maintain and protect organism integrity. Unlike the well-studied immune systems of cells and individuals, little is known about the origins of immunity during the transition to eusociality, a major evolutionary transition comparable to the evolution of multicellular organisms from single-celled ancestors. We aimed to tackle this by characterizing the immune gene repertoire of 18 cockroach and termite species, spanning the spectrum of solitary, subsocial and eusocial lifestyles. We find that key transitions in termite sociality are correlated with immune gene family contractions. In cross-species comparisons of immune gene expression, we find evidence for a caste-specific social defence system in termites, which appears to operate at the expense of individual immune protection. Our study indicates that a major transition in organismal complexity may have entailed a fundamental reshaping of the immune system optimized for group over individual defence.
KW - Social insect
KW - Subsocial
KW - Cockroach
KW - Major transition
KW - Contraction
KW - Expansion
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-538878
DO - https://doi.org/10.1098/rspb.2020.3168
SN - 0962-8452
SN - 1471-2954
VL - 288
IS - 1945
SP - 1
EP - 10
PB - The Royal Society
CY - London
AN - OPUS4-53887
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Karafiludis, Stephanos
A1 - Scoppola, E.
A1 - Wolf, S.E.
A1 - Kochovski, Z.
A1 - Matzdorff, D.
A1 - Van Driessche, A. E. S.
A1 - Hövelmann, J.
A1 - Emmerling, Franziska
A1 - Stawski, Tomasz M.
T1 - Evidence for liquid-liquid phase separation during the early stages of Mg-struvite formation
N2 - The precipitation of struvite, a magnesium ammonium phosphate hexahydrate (MgNH₄PO₄ · 6H₂O) mineral, from wastewater is a promising method for recovering phosphorous. While this process is commonly used in engineered environments, our understanding of the underlying mechanisms responsible for the formation of struvite crystals remains limited. Specifically, indirect evidence suggests the involvement of an amorphous precursor and the occurrence of multi-step processes in struvite formation, which would indicate non-classical paths of nucleation and crystallization. In this study, we use synchrotron-based in situ x-ray scattering complemented by cryogenic transmission electron microscopy to obtain new insights from the earliest stages of struvite formation. The holistic scattering data captured the structure of an entire assembly in a time-resolved manner. The structural features comprise the aqueous medium, the growing struvite crystals, and any potential heterogeneities or complex entities. By analysing the scattering data, we found that the onset of crystallization causes a perturbation in the structure of the surrounding aqueous medium. This perturbation is characterized by the occurrence and evolution of Ornstein-Zernike fluctuations on a scale of about 1 nm, suggesting a non-classical nature of the system. We interpret this phenomenon as a liquid-liquid phase separation, which gives rise to the formation of the amorphous precursor phase preceding actual crystal growth of struvite. Our microscopy results confirm that the formation of Mg-struvite includes a short-lived amorphous phase, lasting >10 s.
KW - Physical and theoretical chemistry
KW - Non-classical crystallization
KW - Struvite
KW - Liquid-liquid-phase-separation
KW - Nucleation
KW - Crystallization
KW - In-situ scattering
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584766
DO - https://doi.org/10.1063/5.0166278
SN - 1089-7690
VL - 159
IS - 13
SP - 1
EP - 12
PB - AIP Publishing
CY - Woodbury, NY
AN - OPUS4-58476
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Heeger, Felix
A1 - Bourne, E. C.
A1 - Wurzbacher, C.
A1 - Funke, E.
A1 - Lipzen, A.
A1 - He, G.
A1 - Ng, V.
A1 - Grigoriev, I. V.
A1 - Schlosser, D.
A1 - Monaghan, M. T.
T1 - Evidence for Lignocellulose-Decomposing Enzymes in the Genome and Transcriptome of the Aquatic Hyphomycete Clavariopsis aquatica
N2 - Fungi are ecologically outstanding decomposers of lignocellulose. Fungal lignocellulose degradation is prominent in saprotrophic Ascomycota and Basidiomycota of the subkingdom Dikarya. Despite ascomycetes dominating the Dikarya inventory of aquatic environments, genome and transcriptome data relating to enzymes involved in lignocellulose decay remain limited to terrestrial representatives of these phyla. We sequenced the genome of an exclusively aquatic ascomycete (the aquatic hyphomycete Clavariopsis aquatica), documented the presence of genes for the modification of lignocellulose and its constituents, and compared differential gene expression between C. aquatica cultivated on lignocellulosic and sugar-rich substrates. We identified potential peroxidases, laccases, and cytochrome P450 monooxygenases, several of which were differentially expressed when experimentally grown on different substrates. Additionally, we found indications for the regulation of pathways for cellulose and hemicellulose degradation. Our results suggest that C. aquatica is able to modify lignin to some extent, detoxify aromatic lignin constituents, or both. Such characteristics would be expected to facilitate the use of carbohydrate components of lignocellulose as carbon and energy sources.
KW - Aquatic fungi
KW - Differential expression
KW - Lignocellulose
KW - Laccase
KW - RNA-Seq
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-536843
DO - https://doi.org/10.3390/jof7100854
VL - 7
IS - 10
SP - 2
EP - 11
PB - MDPI
CY - Basel, Schweiz
AN - OPUS4-53684
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Steinhäuser, Lorin
A1 - Piechotta, Christian
A1 - Westphalen, Tanja
A1 - Kaminski, Katja
T1 - Evaluation, comparison and combination of molecularly imprinted polymer solid phase extraction and classical solid phase extraction for the preconcentration of endocrine disrupting chemicals from representative whole water samples
N2 - Estrogens are endocrine disrupting chemicals and of high concerns due to demonstrated harmful effects on the environment and low effect levels. For monitoring and risk assessment, several estrogens were included in the "watch list" of the EU Water Framework Directive which sets very low environmental quality standard (EQS) levels for Estrone (E1) and 17β-Estradiol (E2) of 0.4 ng L−1 and for 17α-Ethinylestradiol (EE2) of 0.035 ng L−1 requiring sensitive detection methods, as well as extensive sample preparation. A sensitive, derivatization-free, isotope dilution calibration HPLC-MS/MS method for a panel of 5 selected estrogens (including the 3 estrogens of the EU WFD watchlist), and a procedure for the reproducible preparation of a representative whole water matrix including mineral water, humic acids and solid particulate matter are presented. These are used in a diligent comparison of classical solid phase extraction (SPE) on hydrophilic-lipophilic balanced (HLB) phase to SPE on an estrogen-specific molecularly imprinted polymer phase (MISPE) for ultra-trace levels of the analytes (1–10 ng L−1). Additionally, a two-step procedure combining HLB SPE disks followed by MISPE is evaluated. The tow-step procedure provides superior enrichment, matrix removal and sample throughput while maintaining comparable recovery rates to simple cartridge SPE. Estimated method quantification limits (MQLs) range from 0.109–0.184 ng L−1 and thus meet EQS-levels for E1 and E2, but not EE2. The representative whole water matrix provides a reproducible comparison of sample preparation methods and lays the foundation for a certified reference material for estrogen analysis. The presented method will serve as the basis for an extended validation study to assess its use for estrogen monitoring in the environment.
KW - Estrogens
KW - Whole water samples
KW - Molecular imprinted polymers
KW - EU-WFD
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563547
DO - https://doi.org/10.1016/j.talo.2022.100163
SN - 2666-8319
VL - 6
SP - 1
EP - 5
PB - Elsevier B.V.
CY - Amsterdam, Niederlande
AN - OPUS4-56354
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lancaster, Shaun T.
A1 - Sahlin, Eskil
A1 - Oelze, Marcus
A1 - Ostermann, Markus
A1 - Vogl, Jochen
A1 - Laperche, Valérie
A1 - Touze, Solène
A1 - Ghestem, Jean-Philippe
A1 - Dalencourt, Claire
A1 - Gendre, Régine
A1 - Stammeier, Jessica
A1 - Klein, Ole
A1 - Pröfrock, Daniel
A1 - Košarac, Gala
A1 - Jotanovic, Aida
A1 - Bergamaschi, Luigi
A1 - Di Luzio, Marco
A1 - D’Agostino, Giancarlo
A1 - Jaćimović, Radojko
A1 - Eberhard, Melissa
A1 - Feiner, Laura
A1 - Trimmel, Simone
A1 - Rachetti, Alessandra
A1 - Sara-Aho, Timo
A1 - Roethke, Anita
A1 - Michaliszyn, Lena
A1 - Pramann, Axel
A1 - Rienitz, Olaf
A1 - Irrgeher, Johanna
T1 - Evaluation of X-ray fluorescence for analysing critical elements in three electronic waste matrices: A comprehensive comparison of analytical techniques
N2 - As the drive towards recycling electronic waste increases, demand for rapid and reliable analytical methodology to analyse the metal content of the waste is increasing, e.g. to assess the value of the waste and to decide the correct recycling routes. Here, we comprehensively assess the suitability of different x-ray fluorescence spectroscopy (XRF)-based techniques as rapid analytical tools for the determination of critical raw materials, such as Al, Ti, Mn, Fe, Co, Ni, Cu, Zn, Nb, Pd and Au, in three electronic waste matrices: printed circuit boards (PCB), light emitting diodes (LED), and lithium (Li)-ion batteries. As validated reference methods and materials to establish metrological traceability are lacking, several laboratories measured test samples of each matrix using XRF as well as other independent complementary techniques (instrumental neutron activation analysis (INAA), inductively coupled plasma mass spectrometry (ICP-MS) and ICP optical emission spectrometry (OES)) as an inter-laboratory comparison (ILC). Results highlighted key aspects of sample preparation, limits of detection, and spectral interferences that affect the reliability of XRF, while additionally highlighting that XRF can provide more reliable data for certain elements compared to digestion-based approaches followed by ICP-MS analysis (e.g. group 4 and 5 metals). A clear distinction was observed in data processing methodologies for wavelength
dispersive XRF, highlighting that considering the metals present as elements (rather than oxides) induces overestimations of the mass fractions when compared to other techniques. Eventually, the effect of sample particle size was studied and indicated that smaller particle size (<200 μm) is essential for reliable determinations.
KW - XRF
KW - WEEE
KW - PCB
KW - Battery
KW - LED
KW - Recycling
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-614060
DO - https://doi.org/10.1016/j.wasman.2024.10.015
VL - 190
SP - 496
EP - 505
PB - Elsevier B.V.
AN - OPUS4-61406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Erdmann, Maren
A1 - Niebergall, Ute
A1 - Wachtendorf, Volker
A1 - Böhning, Martin
T1 - Evaluation of UV-induced embrittlement of PE-HD by Charpy impact test
N2 - The impact fracture behavior of two common high-density polyethylene grades for container applications were intensively studied by the instrumented Charpy impact test after well-defined exposure to UV-irradiation. Individual stages of the impact event, such as crack initiation and crack propagation energy as well as maximum impact load, were investigated from the recorded load–deflection curves. UV-induced material property changes were further investigated by infrared spectroscopy, differential scanning calorimetry, and dynamic-mechanical analysis as well as density measurements. Based on the results of the Charpy impact test, three indicators were identified to describe the extend of photooxidation on high-density polyethylene: (a) a reduced Charpy impact strength—at least to half of its initial value for a distinctly brittle impact fracture, (b) a marked decrease in the crack propagation contribution to the impact strength, and (c) an increase of the brittle features of the fracture surface.
KW - Degradation
KW - Mechanical properties
KW - Packaging
KW - Polyolefins
KW - Polyethylene
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-509130
DO - https://doi.org/10.1002/APP.49069
SN - 0021-8995
VL - 137
IS - 36
SP - 49069
PB - Wiley
AN - OPUS4-50913
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Jägle, Eva
A1 - Tuladhar, Rujika
A1 - Niederleithinger, Ernst
A1 - Epple, Niklas
A1 - Sanchez Trujillo, Camila Andrea
A1 - Gehlen, Christoph
A1 - Timothy, Jithender J.
T1 - Evaluation of ultrasonic signals collected from laboratory concrete specimens: Preprocessing and analysis with coda wave interferometry
N2 - Efficient maintenance of infrastructure relies on monitoring and assessment of its condition. New technologies and methods thereby enable a deeper understanding of the materials used and of the structures built. Coda Wave Interferometry (CWI) is currently explored for continuous monitoring of reinforced concrete structures as well as material testing. This ultrasound-based method is sensitive to even small material alterations and therefore suitable for the detection of initial damage stages. Herein, a step-by-step procedure for the evaluation of ultrasonic signals with CWI methods is presented. The described procedure is proposed for ultrasonic signals collected with embedded ultrasonic transducers with a center frequency of 50 kHz to 70 kHz from prism-shaped concrete specimen with dimensions of 400 mm x 100 mm x 100 mm. The raw ultrasonic signal, preprocessing and CWI analysis are described and influences of parameters within the analysis are discussed. The presented procedure allows systematic and comparable analysis of ultrasonic signals generated with similar conditions and therefore contributes to the application of CWI methods for structural health monitoring and material testing.
KW - Ultrasound
KW - Concrete
KW - Coda wave interferometry
KW - Structural health monitoring
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656027
DO - https://doi.org/10.1016/j.mex.2026.103811
SN - 2215-0161
VL - 16
SP - 1
EP - 19
PB - Elsevier B.V.
AN - OPUS4-65602
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Diercks, Philipp
A1 - Gläser, Dennis
A1 - Lünsdorf, Ontje
A1 - Selzer, Michael
A1 - Flemisch, Bernd
A1 - Unger, Jörg F.
T1 - Evaluation of tools for describing, reproducing and reusing scientific workflows
N2 - In the field of computational science and engineering, workflows often entail the application of various software, for instance, for simulation or pre- and postprocessing.
Typically, these components have to be combined in arbitrarily complex workflows to address a specific research question. In order for peer researchers to understand, reproduce and (re)use the findings of a scientific publication, several challenges have to be addressed. For instance, the employed workflow has to be automated and information on all used software must be available for a reproduction of the results. Moreover, the results must be traceable and the workflow documented and readable to allow for external verification and greater trust.
In this paper, existing workflow management systems (WfMSs) are discussed regarding their suitability for describing, reproducing and reusing scientific workflows. To this end, a set of general requirements for WfMSs were deduced from user stories that we deem relevant in the domain of computational science and engineering. On the basis of an exemplary workflow implementation, publicly hosted at GitHub (https://github.com/BAMresearch/NFDI4IngScientificWorkflowRequirements), a selection of different WfMSs is compared with respect to these requirements, to support fellow scientists in identifying the WfMSs that best suit their requirements.
KW - FAIR
KW - Reproducibility
KW - Scientific workflows
KW - Tool comparison
KW - Workflow management
PY - 2023
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-584832
DO - https://doi.org/10.48694/inggrid.3726
VL - 1
IS - 1
SP - 1
EP - 27
AN - OPUS4-58483
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Goedecke, Caroline
A1 - Dittmann, Daniel
A1 - Eisentraut, Paul
A1 - Wiesner, Yosri
A1 - Schartel, Bernhard
A1 - Klack, Patrick
A1 - Braun, Ulrike
T1 - Evaluation of thermoanalytical methods equipped with evolved gas analysis for the detection of microplastic in environmental samples
N2 - Microplastic particles are currently detected in almost all environmental compartments. The results of detection vary widely, as a multitude of very different methods are used with very different requirements for analytical validity.
In this work four thermoanalytical methods are compared and their advantages and limitations are discussed. One of them is thermal extraction-desorption gas chromatography mass spectrometry (TED-GC/MS), an analysis method for microplastic detection that has become established in recent years. In addition, thermogravimetric analysis coupled with Fourier-transform infrared spectroscopy (TGA-FTIR) and mass spectrometry (TGA-MS) were applied, two methods that are less common in this field but are still used in other research areas. Finally, microscale combustion calorimeter (MCC) was applied, a method not yet used for microplastic detection.
The presented results are taken from a recently published interlaboratory comparison test by Becker et al. (2020). Here a reference material consisting of suspended matter and specified added polymer masses was examined, and only the results of the recoveries were presented. In the present paper, however, the results for the individual polymers are discussed in detail and individual perspectives for all instruments are shown.
It was found that TED-GC/MS is the most suitable method for samples with unknown matrix and unknown, variable kinds and contents of microplastic. TGA-FTIR is a robust method for samples with known matrix and with defined kinds of microplastic. TGA-MS may offer a solution for the detection of PVC particles in the future. MCC can be used as a very fast and simple screening method for the identification of a potential microplastic load of standard polymers in unknown samples.
KW - Microplastic
KW - TED-GC/MS
KW - TGA-MS
KW - TGA-FTIR
KW - MCC
KW - Thermal analysis
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-516687
DO - https://doi.org/10.1016/j.jaap.2020.104961
VL - 152
SP - 104961
PB - Elsevier B.V.
AN - OPUS4-51668
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Konert, Florian
A1 - Campari, Alessandro
A1 - Nietzke, Jonathan
A1 - Sobol, Oded
A1 - Paltrinieri, Nicola
A1 - Alvaro, Antonio
T1 - Evaluation of the tensile properties of X65 pipeline steel in compressed gaseous hydrogen using hollow specimens
N2 - Hydrogen has great potential on the path towards decarbonization of the energy and transport sectors and can mitigate the urgent issue of global warming. It can be sustainably produced through water electrolysis with potentially zero emissions, and efficiently used (e.g., in fuel cell systems). Despite its environmental advantages, hydrogen-metal interactions could result in the degradation of the mechanical properties of several structural materials. In order to determine the magnitude of the material degradation in relation to hydrogen exposure, extensive material testing is required. The standardized procedure for in-situ testing for the quantification of the impact of compressed gaseous hydrogen (CGH2) relies on the utilization of an autoclave around the tested specimen. Such test set-up is complex, expensive, time-consuming and requires special equipment, trained personnel, and strict safety procedures. A relatively recent method to circumvent these issues and provide affordable results consists of using hollow specimens, thus applying the hydrogen pressure inside rather than outside the specimen. It allows to reduce the volume of hydrogen by several orders of magnitude and to perform the tests more efficiently and in a safer manner. This study focuses on evaluating the tensile properties of X65 vintage pipeline steel tested in a high-pressure hydrogen environment using hollow specimens. Tests are performed in 6 MPa H2 and Ar at the nominal strain rate of 10−6 s−1 to evaluate the reduced area at fracture and the elongation loss. The effect of surface finishing on crack initiation and propagation is investigated by comparing two different manufacturing techniques. In this way, this study provides insights into the applicability of a novel, reliable, and safe testing method which can be used to assess the hydrogen-assisted ductility loss in metallic materials.
KW - Mechanical Engineering
KW - Hydrogen Embrittlement
KW - SSRT
KW - Hollow specimen
KW - Pipeline steel
KW - In-situ tensile test
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595887
DO - https://doi.org/10.1016/j.prostr.2024.01.074
SN - 2452-3216
VL - 54
SP - 1
EP - 8
PB - Elsevier B.V.
AN - OPUS4-59588
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Menga, D.
A1 - de Oliveira Guilherme Buzanich, Ana
A1 - Wagner, F.
A1 - Fellinger, Tim-Patrick
T1 - Evaluation of the Specific Activity of MNCs and the Intrinsic Activity of Tetrapyrrolic FeN4 Sites for the Oxygen Reduction Reaction
N2 - M−N−C electrocatalysts are considered pivotal to replace expensive precious group metal-based materials in electrocatalytic conversions. However, their development is hampered by the limited availability of methods for the evaluation of the intrinsic activity of different active sites, like pyrrolic FeN4 sites within Fe−N−Cs. Currently, new synthetic procedures based on active-site imprinting followed by an ion exchange reaction, e.g. Zn-to-Fe, are producing single-site M−N−Cs with outstanding activity. Based on the same replacement principle, we employed a conservative iron extraction to partially remove the Fe ions from the N4 cavities in Fe−N−Cs. Having catalysts with the same morphological properties and Fe ligation that differ solely in Fe content allows for the facile determination of the decrease in density of active sites and their turn-over frequency. In this way, insight into the specific activity of M−N−Cs is obtained and for single-site catalysts the intrinsic activity of the site is accessible. This new approach surpasses limitations of methods that rely on probe molecules and, together with those techniques, offers a novel tool to unfold the complexity of Fe−N−C catalyst and M−N−Cs in general.
KW - Fe-N-C catalysts
KW - M-N-C catalysts
KW - Fuel Cells
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-567406
DO - https://doi.org/10.1002/anie.202207089
SN - 1433-7851
VL - 61
IS - 50
SP - 1
EP - 6
PB - Wiley-VHC
AN - OPUS4-56740
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
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 - Fischer, Franziska
A1 - Scholz, G.
A1 - Benemann, Sigrid
A1 - Rademann, K.
A1 - Emmerling, Franziska
T1 - Evaluation of the formation pathways of cocrystal polymorphs in liquid-assisted syntheses
N2 - The synthesis of the polymorphic cocrystal caffeine:anthranilic acid was investigated to obtain a better understanding of the processes leading to the formation of different polymorphic forms. In the case of these cocrystal polymorphs synthesized by liquid-assisted grinding a distinct influence of the dipole moment of the solvent was found. A pre-coordination between the solvent molecules and the caffeine:anthranilic acid cocrystal could be identified in the formation of form II. In the case of form II the solvent can be regarded as a catalyst. The formation pathway of each polymorph was evaluated using synchrotron X-ray diffraction.
KW - cocrystal
KW - synchrotron X-ray diffraction
KW - caffeine
PY - 2014
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-313222
DO - https://doi.org/10.1039/c4ce00472h
SN - 1466-8033
VL - 16
IS - 35
SP - 8272
EP - 8278
CY - London, UK
AN - OPUS4-31322
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
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 - Costabel, S.
A1 - Hiller, Thomas
A1 - Dlugosch, R.
A1 - Kruschwitz, Sabine
A1 - Müller Petke, M.
T1 - Evaluation of single-sided nuclear magnetic resonance technology for usage in geosciences
N2 - Because of its mobility and ability to investigate exposed surfaces, single-sided (SiS) nuclear magnetic resonance (NMR) technology enables new application fields in geosciences. To test and assess its corresponding potential, we compare longitudinal (T1) and transverse (T2) data measured by SiS NMR with those of conventional geoscientific laboratory NMR. We use reference sandstone samples covering a broad range of pore sizes. Our study demonstrates that the lower signal-to-noise ratio of SiS NMR data generally tends to slightly overestimated widths of relaxation time distributions and consequently pore size distributions. While SiS and conventional NMR produce very similar T1 relaxation data, unbiased SiS NMR results for T2 measurements can only be expected for fine material, i.e. clayey or silty sediments and soils with main relaxation times below 0.05s. This limit is given by the diffusion relaxation rate due to the gradient in the primary magnetic field associated with the SiS NMR. Above that limit, i.e. for coarse material, the relaxation data is strongly attenuated. If considering the diffusion relaxation time of 0.2 s in the numerical data inversion process, the information content >0.2s is blurred over a range larger than that of conventional NMR. However, our results show that principle range and magnitudes of the relaxation time distributions are reconstructed to some extent. Regarding these findings, SiS NMR can be helpful to solve geoscientific issues, e.g. to assess the hydro-mechanical properties of the walls of underground facilities or to provide local soil moisture data sets for calibrating indirect remote techniques on the regional scale. The greatest opportunity provided by the SiS NMR technology is the acquisition of profile relaxation data for rocks with significant bedding structures at the µm scale. With this unique feature, SiS NMR can support the understanding and modeling of hydraulic and diffusional anisotropy behavior of sedimentary rocks.
KW - Single-sided NMR
KW - Geosciences
KW - Nuclear magnetic resonance
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-561676
DO - https://doi.org/10.1088/1361-6501/ac9800
SN - 0957-0233
VL - 34
IS - 1
SP - 1
EP - 13
PB - IOP Publishing
AN - OPUS4-56167
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Rabe, U.
A1 - Pudovikov, S.
A1 - Herrmann, H.-G.
A1 - Wiggenhauser, H.
A1 - Prabhakara, Prathik
A1 - Niederleithinger, Ernst
T1 - Evaluation of retroreflective corner echo for detection of surface breaking cracks in concrete by ultrasound
N2 - The retroreflective corner echo is used, for example, in ultrasonic non-destructive testing of metals to find fatigue cracks in tubes or shafts. If the much weaker crack tip signal is additionally detected, the crack length can also be determined. A corner reflection occurs in cases of surface breaking cracks with predominantly perpendicular orientation to the surface. The intensity of the corner reflection depends on the angle of incidence and on the ultrasonic wave mode used. For the reliable detection of vertical surface breaking cracks in metals, transversal waves are commonly used, which propagate at an angle of 37° to 53° to the inspection surface. As shown in this contribution, the wide spread low frequency ultrasonic arrays with dry point contact sources available for ultrasonic testing of concrete also allow to receive corner echoes. These devices generate transversal waves in concrete structures with a large divergence of the sound field. A series of experiments was carried out with such dry point contact arrays on concrete specimens with artificial test defects and controlled induced cracks of different depths. The ultrasonic time-of-flight signals were recorded, exported and reconstructed utilising the SAFT (Synthetic Aperture Focusing Technique) algorithm. The SAFT reconstruction parameters were adjusted to visualize the corner echo indication. As will be shown, with this targeted processing, the reproducible detection of surface breaking cracks in concrete is possible. The retroreflective corner echo can thus be exploited in civil engineering for non-destructive inspection of concrete.
T2 - NDT-CE 2022
CY - Zurich, Switzerland
DA - 16.08.2022
KW - Concrete
KW - Crack depth
KW - Ultrasound
KW - SAFT
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-563365
UR - https://www.ndt.net/article/ndtce2022/paper/27256_manuscript.pdf
IS - 27256
SP - 1
EP - 4
PB - NDT.net
AN - OPUS4-56336
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lozano-Martín, Daniel
A1 - Tuma, Dirk
A1 - Chamorro, César R.
T1 - Evaluation of Reference Equations of State for Density Prediction in Regasified LNG Mixtures Using High-Precision Experimental Data
N2 - This study evaluates the performance of three reference equations of state (EoS), AGA8-DC92, GERG-2008, and SGERG-88, in predicting the density of regasified liquefied natural gas (RLNG) mixtures. A synthetic nine-component RLNG mixture was gravimetrically prepared. High-precision density measurements were obtained using a single-sinker magnetic suspension densimeter over a temperature range of (250 to 350) K and pressures up to 20 MPa. The experimental data were compared with EoS predictions to evaluate their accuracy. AGA8-DC92 and GERG-2008 showed excellent agreement with the experimental data, with deviations within their stated uncertainty. In contrast, SGERG-88 exhibited significantly larger deviations for this RLNG mixture, particularly at low temperatures of (250 to 260) K, where discrepancies reached up to 3 %. Even at 300 K, deviations larger than 0.4 % were observed at high pressures, within the model’s uncertainty, but notably higher than those of the other two EoSs. The analysis was extended to three conventional 11-component natural gas mixtures (labeled G420 NG, G431 NG, and G432 NG), previously studied by our group using the same methodology. While SGERG-88 showed reduced accuracy for the RLNG mixture, it performed reasonably well for these three mixtures, despite two of them have a very similar composition to the RLNG. This discrepancy is attributed to the lower CO2 and N2 content typical in RLNG mixtures, demonstrating the sensitivity of EoS performance to minor differences in composition. These findings highlight the importance of selecting appropriate EoS models for accurate density prediction in RLNG applications.
KW - Regasified LNG
KW - Equation of state
KW - Density
KW - Gravimetric preparation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646506
DO - https://doi.org/10.1007/s10765-025-03669-4
SN - 0195-928X
VL - 46
SP - 1
EP - 25
PB - Springer Science and Business Media LLC
CY - Heidelberg
AN - OPUS4-64650
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, Daniel
A1 - Müller, Christina
A1 - Pitkänen, J.
T1 - Evaluation of radiographic testing performance with an advanced POD approach
N2 - POD is the most often used approach for the evaluation of the reliability of non-destructive testing methods in critical areas. But especially for those cases the requirements for a sufficient amount of data, adequate type of defects and the statistical requirements are high. The claim for checking these requirements is not new, but never the less often ignored. Especially the large amount of data for critical real defects seems too often to be not really solvable. In this presentation we show an approach to use real defect data with knowledge from former testing results with the same equipment, in a useful adequate way. Furthermore we introduce a method to evaluate the real defect description parameters for the radiographic testing. This approach was used for a joint project with the company POSIVA, which is building a final depository for spent nuclear fuel in Finland. Radiographic testing is one of the NDT-methods they use to test the electron beam weld of the copper canister. The copper canister will be used in the deposit as a corrosion barrier within the deposit concept. Through the high sophisticated manufacturing methods of the canister there are almost no material defects, which could be used for reliability evaluation. In this context the idea of Bayesian Updating of the POD with real defect data with former results from artificial defect data was born to get a useful evaluation.
T2 - 5th European-American workshop on reliability of NDE
CY - Berlin, Germany
DA - 07.10.2013
PY - 2013
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-312641
SN - 978-3-940283-53-5
IS - DGZfP-BB 144
SP - Lecture 4, 1
EP - 7
PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP)
CY - Berlin
AN - OPUS4-31264
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Bachmann, Marcel
A1 - Meng, Xiangmeng
A1 - Artinov, Antoni
A1 - Rethmeier, Michael
T1 - Evaluation of narrowed weld pool shapes and their effect on resulting potential defects during deep penetration laser beam welding
N2 - This study presents mechanisms of the evolution of a narrowed region in the weld pool center during deep penetration laser beam welding. In numerous numerical studies presented in this study, it was also found that the local reduction of the weld pool size can cause detrimental effects on the melt flow behavior and the resulting properties of the welds. A particularly large influence of this effect was identified in three aspects. First, the local variation of the solidification sequence of the weld pool causes an increase in the hot-cracking susceptibility due to a locally delayed solidification. Second, it was proven that a change in the local length and width of the weld pool is associated with an adverse impact on the potential flow routes of the molten material that induces stronger local variations of its solidification. Thus, the element mixing, e.g., during the welding with filler materials, is blocked. This leads to a non-homogeneous chemical composition of the final weld and can cause undesired effects on the final material properties. Finally, another observed effect is related to the reduced ability of process pores to reach the top surface. As this type of porosity is usually produced around the keyhole tip, the change of the fluid flow regime above this area plays a significant role in determining the final path of the pores until the premature solidification in the middle of the weld pool captures them. This study summarizes mainly numerical results that were supported by selected experimental validation results.
KW - Weld pool shape
KW - Laser beam welding
KW - Solidification
KW - Porosity
KW - Numerical process simulation
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-557759
DO - https://doi.org/10.2351/7.0000733
SN - 1042-346X
VL - 34
IS - 4
SP - 1
EP - 7
PB - Laser Institute of America
CY - Orlando, Fla.
AN - OPUS4-55775
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Olscher, C.
A1 - Jandric, A.
A1 - Zafiu, C.
A1 - Part, Florian
T1 - Evaluation of marker materials and spectroscopic methods for tracer-based sorting of plastic wastes
N2 - Plastics are a ubiquitous material with good mechanical, chemical and thermal properties, and are used in all industrial sectors. Large quantities, widespread use, and insufficient management of plastic wastes lead to low recycling rates. The key challenge in recycling plastic waste is achieving a higher degree of homogeneity between the different polymer material streams. Modern waste sorting plants use automated sensor-based sorting systems capable to sort out commodity plastics, while many engineering plastics, such as polyoxymethylene (POM), will end up in mixed waste streams and are therefore not recycled. A novel approach to increasing recycling rates is tracer-based sorting (TBS), which uses a traceable plastic additive or marker that enables or enhances polymer type identification based on the tracer’s unique fingerprint (e.g., fluorescence). With future TBS applications in mind, we have summarized the literature and assessed TBS techniques and spectroscopic detection methods. Furthermore, a comprehensive list of potential tracer substances suitable for thermoplastics was derived from the literature. We also derived a set of criteria to select the most promising tracer candidates (3 out of 80) based on their material properties, toxicity profiles, and detectability that could be applied to enable the circularity of, for example, POM or other thermoplastics.
KW - Circular economy
KW - Post-consumer plastic waste
KW - Plastic waste recycling
KW - Tracer-based sorting
KW - Sensor-based sorting
KW - Spectroscopy
KW - Fluorescent markers
KW - Thermoplastics
KW - Polyoxymethylene
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-555624
DO - https://doi.org/10.3390/polym14153074
SN - 2073-4360
VL - 14
SP - 1
EP - 20
PB - MDPI
CY - Basel
AN - OPUS4-55562
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Deresse, N. E.
A1 - Thiele, Marc
A1 - Pirskawetz, Stephan
A1 - Sarem, M.
A1 - Francois, St.
A1 - Verstrynge, E.
T1 - Evaluation of Concrete Fatigue Damage with Elastic Wave-based Measurement Techniques
N2 - The fatigue damage evolution and the fatigue life of quasi-brittle materials such as concrete are not yet completely understood. Accordingly to get better insights, researchers have recently been incorporating advanced measuring techniques in their fatigue experiments. In this research, acoustic emission techniques (AET), active ultrasonic, and deformation measurements are used to track the damage evolution of concrete samples subjected to fatigue loading. The samples are subjected to constant amplitude and stepwise fatigue loading in Brazilian splitting test set-ups. Initially, a good agreement is observed between the deformation and the ultrasonic measurements in capturing the crack propagation during Brazilian splitting tests. The three fatigue damage phases could be identified with all of the three techniques. The Phase II damage rates quantified by deformation measurements and AET in stepwise fatigue tests were used to predict the number of cycles to failure at various stress
levels. The predictions were validated using the number of cycles to failure of the constant amplitude fatigue tests.
T2 - 36th Conference of the European Working Group on Acoustic Emission
CY - Potsdam, Germany
DA - 18.09.2024
KW - Concrete
KW - Acoustic emission
KW - Ultrasonic testing
KW - Fatigue
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-615677
DO - https://doi.org/10.58286/30228
SN - 1435-4934
VL - 29
IS - 10
SP - 1
EP - 10
PB - NDT.net
AN - OPUS4-61567
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Zettner, Alina
A1 - Gojani, Ardian
A1 - Schmid, Thomas
A1 - Gornushkin, Igor B.
T1 - Evaluation of a Spatial Heterodyne Spectrometer for Raman Spectroscopy of Minerals
N2 - Spatial heterodyne spectroscopy (SHS) is a novel spectral analysis technique that is being applied for Raman spectroscopy of minerals. This paper presents the theoretical basis of SHS and its application for Raman measurements of calcite, quartz and forsterite in marble, copper ore and nickel ore, respectively. The SHS measurements are done using a broadband (518–686 nm) and resolving power R ≈ 3000 instrument. The spectra obtained using SHS are compared to those obtained by benchtop and modular dispersive spectrometers. It is found that SHRS performance in terms of resolution is comparable to that of the benchtop spectrometer and better than the modular dispersive spectrometer, while the sensitivity of SHRS is worse than that of a benchtop spectrometer, but better than that of a modular dispersive spectrometer. When considered that SHS components are small and can be packaged into a handheld device, there is interest in developing an SHS-based Instrument for mobile Raman spectroscopy. This paper evaluates the possibility of such an application.
KW - Forsterite
KW - Spatial heterodyne spectrometer
KW - Interferometric spectroscopy
KW - Fourier transform spectroscopy
KW - Raman spectroscopy
KW - Calcite
KW - Quartz
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504624
DO - https://doi.org/10.3390/min10020202
VL - 10
IS - 2
SP - 202
PB - MDPI
CY - Basel, Switzerland
AN - OPUS4-50462
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Janczynski, Jessica
A1 - Tewes, Andreas
A1 - Ulbricht, Alexander
A1 - Jaenisch, Gerd-Rüdiger
T1 - Evaluation Metrics for Comparison between Virtual and Industrial XCT
N2 - Simulations of XCT systems, as employed in the context of the manufacturing and design process, represent a time-saving, cost- and resource-efficient alternative to repeated experimental measurements. This article is dedicated to the development and evaluation of various metrics that should enable an adequate verification and optimization of a XCT simulation of an experimental XCT system. The present study employed statistical evaluation as a methodological approach. The present article makes a significant contribution to the optimization of the development process of a XCT simulation and provides a foundation for future research activities in this field.
KW - Computed Tomography
KW - Computertomographie
KW - aRTist
KW - Simulation
KW - Virtual CT
KW - Evaluation
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641444
DO - https://doi.org/10.1007/s10921-025-01213-w
SN - 0195-9298
VL - 44
IS - 4
SP - 1
EP - 11
PB - Springer Science and Business Media LLC
CY - Berlin/Heidelberg
AN - OPUS4-64144
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Frenzel, Olivia
A1 - Westphalen, Tanja
A1 - Kaminski, Katja
A1 - Kluge, Stephanie
A1 - Bücker, Michael
A1 - Piechotta, Christian
T1 - Evaluation and Validation of an Accelerated Weathering Procedure to Characterise the Release of Bisphenol A from Polycarbonate Under Exposure to Simulated Environmental Conditions
N2 - Bisphenol A (BPA) has been listed as a substance of very high concern (SVHC) due to its endocrine-disrupting properties according to REACH in 2017. European competent authorities have prepared a REACH restriction proposal to reduce BPA levels in the environment. The proposed limit for the concentration of free BPA and other bisphenols in articles is 10 mg kg−1. If exceeded, migration testing can demonstrate that no more than 0.04 mg L−1 is released from the product or material over its lifetime. German authorities are drafting a new restriction proposal after the original was temporarily withdrawn. The residual and migration limits mentioned above were key requirements from the previous restriction proposal. Numerous national and international standards exist for assessing how environmental factors affect the physical and chemical properties of products and materials—such as notch impact strength and tensile strength—but these standards do not cover the release of pollutants. A standardised procedure that covers all aspects of artificial weathering and monitors the subsequent release of pollutants is necessary, especially in the context of the regulation of these substances. An accelerated weathering procedure was established for non-protected samples. This material was not intended for outdoor applications. The testing procedure applied a typical weathering scenario that represents Central European climate conditions. The procedure was validated and applied to samples under distinct quality assurance aspects. Released BPA is quantified via an organic isotope dilution LC-MS/MS method. In parallel, identical samples were weathered outdoors on a weathering rack. Haze and yellowness index are measured to compare outdoor and weathering chamber results.
KW - Artificial weathering
KW - Polycarbonate
KW - Bisphenol A
KW - Simulated environmental conditions
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645020
DO - https://doi.org/10.3390/app151910361
SN - 2076-3417
VL - 15
IS - 19
SP - 1
EP - 15
PB - MDPI AG
AN - OPUS4-64502
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Mirwald, Johannes
A1 - Khalighi, Sadaf
A1 - Varveri, Aikaterini
A1 - Hofko, Bernhard
A1 - Adwani, Dheeraj
A1 - Cannone-Falchetto, Augusto
A1 - Elwardany, Michael
A1 - Kleiziené, Rita
A1 - Konieczna, Katarzyna
A1 - Maliszewski, Maciej
A1 - Mouillet, Virginie
A1 - Nahar, Sayeda
A1 - Piérard, Nathalie
A1 - Pipintakos, Georgios
A1 - Porot, Laurent
A1 - Primerano, Kristina
A1 - Sharma, Aditi
A1 - Tavassoti, Pejoohan
A1 - Weigel, Sandra
A1 - Wetekam, Jens
A1 - Zhu, Jiqing
T1 - Evaluating the reproducibility and consistency of different sample preparation techniques used for ATR-FTIR spectroscopy from the RILEM 295-FBB TG1 round robin test
N2 - Attenuated Total Reflection Fourier Transform Infrared spectroscopy has become a popular spectroscopic technique in bituminous binder analysis. However, comparable results are not obtainable yet due to differences in devices, measurement routines, sample preparation procedures, and spectral evaluation. Thus, the Task Group 1 of the RILEM TC 295-FBB: “Fingerprinting bituminous binders using physicochemical analysis” focuses on bringing this method towards pre-standardization. This study evaluates the reproducibility and consistency from round robin test, where 21 participating laboratories performed six different preparation techniques on three different binders in an unaged, short-term, and long-term aged state. A total of 6461 spectra were recorded and evaluated for their mean, standard deviation and coefficient of variation (CV) in the spectral region between 1800 and 600 cm−1. The results show that the solid sample preparation methods provide excellent reproducibility, with a coefficient of variation below 2%. Only the solvent method showed a higher coefficient of variation at 7.18%. Outliers with a high CV were detected and categorized into two groups: one where only one of the four samples differed and the other where all 16 spectra showed slight scattering in the overall absorption. The consistency of the method is significantly influenced by the accuracy of sample preparation, which is crucial for minimizing differences in slope, baseline, and noise in the spectra. These findings show the excellent reproducibility of these sample preparation methods and will be further examined to establish universal indices for evaluating effects such as ageing, bringing the method closer towards standardization.
KW - Bitumen
KW - FTIR-Spektroskopie
KW - Reproducibility
KW - Round robin test
KW - Material handling
KW - preparation routine
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-645386
DO - https://doi.org/10.1617/s11527-025-02755-1
SN - 1359-5997
VL - 58
IS - 8
SP - 1
EP - 21
PB - Springer Science and Business Media LLC
AN - OPUS4-64538
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - CONF
A1 - Kanzler, D.
A1 - Müller, Christina
T1 - Evaluating RT systems with a new POD approach
N2 - The usefulness and purpose of evaluating nondestructive testing (NDT) systems and their capabilities has changed in the last decade. The conventional method of simply applying a familiar statistical algorithm to say whether the system is usable for the tasks is history.
Nowadays, multiple parameter methods which describe the probabilities of detection (POD) of different systems or real defects need new characteristics and a broader variety of statistical models to describe the true system behaviour. The appraisal of the NDT system involves diverse departments within a company (engineering, NDT-operators, and statisticians), but is, at the same time, more needed and requested than in the past. In this article, an approach is discussed in which professionals from different fields worked well together, accomplishing cost-intensive metallographic studies in correlation with well-understood physical behaviour of NDT-methods as well as deep-discussed mathematical methods to create a holistic evaluation of the technical reliability for a specific radiographic testing (RT) equipment. The first part of the publication will show the comparison between metallographic grinding and the RT indications. An essential innovation over past evaluation methods was the use of a multi-scale smoothing algorithm, which describes physical parameters, which were not used in evaluation like the POD in this way in the past.
In the second part the statistical requirements for the POD take the focus. It can often be hard to make significant statements; especially in the case where only a small amount of data is available. The combination of data and the use of knowledge from simulations are essential. One possible solution will be shown for the RT evaluation. The methodology is used for evaluating the digital RT system for the inspection of electron-beam welds, which was method considered to seal the Finnish copper canisters for the final deposit of spent nuclear fuel.
T2 - 19th World Conference on Non-Destructive Testing
CY - München, Germany
DA - 13.06.2016
KW - NDT
KW - Reliability
KW - POD
KW - RT
PY - 2016
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-375732
UR - http://www.ndt.net/article/wcndt2016/papers/we1d4.pdf
SP - id 19535, 1
EP - 8
AN - OPUS4-37573
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Anderson, J.
A1 - Boström, L.
A1 - Chiva, R.
A1 - Guillaume, E.
A1 - Colwell, S.
A1 - Hofmann-Böllinghaus, Anja
A1 - Toth, P.
T1 - European approach to assess the fire performance of façades
N2 - Several attempts have been made in the past to develop a European harmonized testing and assessment method for façades before the European commission decided to publish a call for tender on the topic. A project consortium from five countries (Sweden, UK, France, Germany and Hungary) applied to the call for tender and was contracted to develop a European approach to assess the fire performance of façades. 24 sub-contractors and 14 stakeholder entities were part of the project. The objective of the European project was to address a request from the Standing Committee of Construction (SCC) to provide EC Member States regulators with a means to regulate the fire performance of façade systems based on a European Approach agreed by SCC. The initial stages of this Project were focused on establishing a Register of the regulatory requirements in all Member States in relation to the fire Performance of façade systems, and to identify those Member States who have regulatory requirements for the fire performance façade systems which go beyond the current EN 13501 (reaction to fire and fire resistance) classification systems and to collate the details of these additional requirements. After having confirmed the regulatory needs a testing and classification methodology based on BS 8414 and DIN 4102-20 was developed to address the identified key performance and classification characteristics.
This paper is a short overview of results the two-year development work, which Final Report published by the European Commission in 2018.
KW - Facade
KW - Regulation
KW - Testing
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-530501
DO - https://doi.org/10.1002/fam.2878
SN - 1099-1018
VL - 45(5)
IS - Special issue: Facade fire safety
SP - 598
EP - 608
PB - Wiley
CY - Oxford
AN - OPUS4-53050
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Stroh, Julia
A1 - Ali, Naveed Zafar
A1 - Maierhofer, Christiane
A1 - Emmerling, Franziska
T1 - Ettringite via Mechanochemistry: A Green and Rapid Approach for Industrial Application
N2 - Here, we report on a first mechanochemical synthesis of ettringite, an important cement hydrate phase. The mineral compound ettringite ([Ca3Al(OH)6]2·(SO4)3·26H2O) occurs rarely in nature, but is common for cement-based materials. Ettringite has wide technical application in the ceramic and paper industry. However, its typical wet-chemical synthesis is cumbersome and produces waste water and CO2 emissions. Here, we investigate the first mechanochemical synthesis of ettringite for developing an easy and sustainable alternative for industrial application. The mechanosynthesis was monitored in situ by coupled synchrotron X-ray diffraction (XRD) and infrared thermography (IRT). The consumption of the reactants and the formation of the reaction product were monitored with time-resolved XRD. IRT showed the temperature increase based on the exothermic reaction. The reaction conversion was significantly improved changing the strategy of the mechanosynthesis from a one- to a two-step process. The latter included neat pregrinding of solid reactants followed by a delayed addition of the stoichiometric amount of water. Thus, an increase of reaction conversion from 34 to 94% of ettringite could be achieved.
KW - XRD
KW - Mechanochemistry
KW - Ettringite
KW - In situ
PY - 2019
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-479016
DO - https://doi.org/10.1021/acsomega.9b00560
SN - 2470-1343
VL - 4
IS - 4
SP - 7734
EP - 7737
PB - ACS Publications
CY - Washington, DC
AN - OPUS4-47901
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hu, W.-H.
A1 - Xu, Z.-M.
A1 - Liu, M.-Y.
A1 - Tang, D.-H.
A1 - Lu, W.
A1 - Li, Z.-H.
A1 - Teng, J.
A1 - Han, X.-H.
A1 - Said, Samir
A1 - Rohrmann, R. G.
T1 - Estimation of the Lateral Dynamic Displacement of High-Rise Buildings underWind Load Based on Fusion of a Remote Sensing Vibrometer and an Inclinometer
N2 - This paper proposes a novel method to estimate the lateral displacement of high-rise structures under wind loads. The coefficient β(x) is firstly derived, reflecting the relation between the structural lateral dynamic displacement and the inclination angle at the height x of a structure. If the angle is small, it is the ratio between the structural fundamental mode shape and its first-order derivative without influence of external loads. Several dynamic experiments of structures are performed based on a laser remote sensing vibrometer and an inclinometer, which shows that the fundamental mode is dominated in the structural displacement response under different types of excitations. Once the coefficient β(x) is curve-fitted by measuring both the structural lateral dynamic displacement and the inclination angle synchronously, the real-time structural lateral displacement under operational conditions is estimated by multiplying the coefficient β(x) with the inclination angle. The advantage of the proposed method is that the coefficient β(x) can be identified by lateral dynamic displacement measured in high resolution by the remote sensing vibrometer, which is useful to reconstruct the displacement accurately by the inclination angle under operational conditions
KW - Inclination angle
KW - High-rise building
KW - Lateral dynamic displacement
KW - Remote sensing vibrometer
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-506833
DO - https://doi.org/10.3390/rs12071120
VL - 12
IS - 7
SP - 1120
PB - MDPI
CY - 4052 Basel, Schweiz
AN - OPUS4-50683
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Madia, Mauro
A1 - Zerbst, Uwe
A1 - Werner, Tiago
T1 - Estimation of the Kitagawa-Takahashi diagram by cyclic R curve analysis
N2 - The Kitagawa-Takahashi (KT) diagram is a proven concept for describing the fatigue limit in presence of a defect or crack. It can be determined empirically with great experimental effort. It can also be estimated by means of the El Haddad relationship if the endurance limit and the long fatigue crack propagation threshold are available in reasonable accuracy. A third option is the determination using the cyclic R-curve, which describes the dependency of the fatigue crack propagation threshold on the crack growth at the short crack propagation stage. This can be experimentally determined using a closure-free initial pre-crack. It can then be applied to the determination of crack arrest for a given applied load and a given defect or crack size. Compared to the other two methods mentioned above, this option has considerable advantages: It can be applied to any component and any stress ratio. It allows the treatment of multiple cracks and provides estimations of the S-N curve in the finite life regime as well as at the endurance limit. Compared to the empirical determination of the KT diagram, the experimental effort is significantly lower and compared to the El Haddad approach it avoids problems such as the use of non-conservative long fatigue crack propagation thresholds (when the conventional load reduction method is applied to materials prone to corrosion) and the mathematical predetermination of the curve shape. The work introduces the method and provides a critical discussion as well as quantitative comparison between the different methods.
T2 - FATIGUE DESIGN 2021
CY - Online meeting
DA - 17.11.2021
KW - Fatigue life
KW - Endurance limit
KW - Kitagawa-Takahashi diagram
KW - Cyclic R-curve
PY - 2022
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-544931
DO - https://doi.org/10.1016/j.prostr.2022.03.032
SN - 2452-3216
VL - 38
SP - 309
EP - 316
PB - Elsevier B.V.
AN - OPUS4-54493
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Romero-Navarrete, José A.
A1 - Otremba, Frank
A1 - Lozano Guzman, A. A.
T1 - Estimation of the effect of the driving style on pollutants emission by heavy trucks
N2 - Different approaches have been attempted so far to reduce fuel consumption and linked pollutants, including vehicle equipment and design, with rational driving style being recognized as a potential source of fuel savings. However, no specific methodology had been suggested so far to assess fuel economy of driving other than the fuel consumed itself. In this paper, the Standard deviation of driving acceleration has been found to be directly associated to fuel consumption, so that the less dispersion of the driving acceleration, produces the lower fuel consumptions and emissions. Such metric could be thus used to assess driving style.
KW - Driving style
KW - Fuel consumption
KW - Stored energy
KW - GPS data
KW - Simulation
KW - Particle emissions
PY - 2020
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-511540
UR - https://www.iaras.org/iaras/home/caijes/estimation-of-the-effect-of-the-driving-style-on-pollutants-emission-by-heavy-trucks
SN - 2367-8941
VL - 5
SP - 220
EP - 226
PB - IARAS
CY - Sofia
AN - OPUS4-51154
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Völker, Tobias
A1 - Mensing, Friedrich
A1 - Kruschwitz, Sabine
T1 - Estimation of cement content in concrete by spatially resolved laser induced breakdown spectroscopy
N2 - The cement content in concrete significantly influences critical properties such as durability, permeability, strength, and workability. Traditional methods for estimating the cement content face limitations. These include the need for comprehensive chemical and solubility knowledge, extensive sample preparation, and their time-consuming and destructive nature. This study investigates the application of laser-induced breakdown spectroscopy (LIBS) as an alternative method. It involves probing concrete samples with high spatial resolution and analyzing the resultant spectra. The methodology is first tested on mesoscale concrete models to assess limitations and inherent errors. Subsequently, the methodology is applied to actual concrete samples with varying cement content and aggregate size distributions. The results demonstrate a promising accuracy, with an average relative error of approximately 8%. This paper offers a comprehensive evaluation of the method's advantages, limitations, and factors influencing its practical applicability in field conditions.
KW - LIBS
KW - Spectroscopy
KW - Cement content
KW - Elemental mapping
PY - 2024
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-620112
DO - https://doi.org/10.1016/j.cemconres.2024.107714
SN - 1873-3948
VL - 189
SP - 1
EP - 10
PB - Elsevier Ltd.
AN - OPUS4-62011
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Dub, S.
A1 - Haftaoglu, Cetin
A1 - Kindrachuk, Vitaliy
T1 - Estimate of theoretical shear strength of C60 single crystal by nanoindentation
N2 - The onset of plasticity in a single crystal C60 fullerite was investigated by nanoindentation on the (111) crystallographic plane. The transition from elastic to plastic deformation in a contact was observed as pop-in events on loading curves. The respective resolved shear stresses were computed for the octahedral slip systems ⟨011¯¯¯⟩{111}, supposing that their activation resulted in the onset of plasticity. A finite element analysis was applied, which reproduced the elastic loading until the first pop-in, using a realistic geometry of the Berkovich indenter blunt tip. The obtained estimate of the C60 theoretical shear strength was about 1/11 of the shear modulus on {111} planes.
KW - Finite element analysis
KW - Fullerite
KW - Nanoindentation
PY - 2021
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-523208
DO - https://doi.org/10.1007/s10853-021-05991-2
VL - 56
IS - 18
SP - 10905
EP - 10914
PB - Springer Nature
AN - OPUS4-52320
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Hartmann, Yannic
A1 - El Abbassi, Abdelouahad
A1 - Mayer, Bernhard
A1 - Resch-Genger, Ute
A1 - Müller, Thomas J. J.
T1 - Ester‐Aroyl‐S,N‐Ketene Acetals with Solid‐State Luminescence: AIEgens from Sequential Three‐Component Desymmetrization
N2 - AbstractDi(hetero)aroyl dichlorides are desymmetrized upon sequential reaction with alcohols and 2‐methyl N‐benzyl thiazolium salts within the course of a one‐pot three‐component reaction yielding ester‐substituted aroyl‐S,N‐ketene acetals under mild conditions in good yields. A prerequisite for the concise one‐pot process is the different nucleophilicity of the alcohols and in situ generated S,N‐ketene acetals. The resulting compounds are merocyanines with dominant charge‐transfer absorption bands which are fluorescent in the solid state, but not in solution. In water/ethanol solvent mixtures of increasing water content, the water‐insoluble dyes display typical aggregation‐induced emission (AIE) characteristics. The water fraction inducing AIE as well as the emission color, and fluorescence quantum yield (Φf) of the aggregated dyes can be controlled by the alcohol part of the ester moiety. Encapsulation into polystyrene nanoparticles can lead to a considerable increase of the fluorescence quantum yield Φf to 30% as shown for a representatively chosen dye revealing the highest Φf of 11% within the dye series in the water/ethanol mixtures and enabling the usage of these dyes as fluorescent reporters in aqueous environments.
KW - Dye
KW - Fluorescence
KW - Aggregation
KW - Mechanism
KW - Signal enhancement
KW - Nano
KW - Particle
KW - Characterization
KW - Quantum yield
KW - Photophysics
KW - Probe
KW - Sensor
KW - Lifetime
KW - Polarity
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-642400
DO - https://doi.org/10.1002/chem.202502071
SN - 0947-6539
SP - 1
EP - 10
PB - Wiley-VCH
CY - Weinheim
AN - OPUS4-64240
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
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 - Lucka, R.
A1 - Elshani, B.
A1 - Kilic, M. S.
A1 - Klimke, S.
A1 - Krüger, C.
A1 - Menzel, Michael
A1 - Stößer, R.
A1 - Titiš, J.
A1 - Boča, R.
A1 - Renz, F.
T1 - ESR and Mössbauer spectroscopy of iron(III) spin crossover complexes based on pentadentate Schiff base ligands with pseudohalide coligands
N2 - Two iron(III) spin crossover complexes [Fe(5Cl-L)(NCS)] (1) and [Fe(5Cl-L)(NCSe)] (2) were synthesized with the pentadentate Schiff base ligand 5Cl-L and thiocyanato and selenocyanato as coligands. 5Cl-L, as an asymmetric {N3O2} donor Schiff base, was synthesized by a condensation reaction of 5-chlorosalicyladehyde using the asymmetric N-(2-aminoethyl)-1,3-propanediamine. The complexes exhibited a spin crossover at 280 (1) and 293 K (2), respectively, and were subjected to electron spin resonance (ESR) and Mössbauer spectroscopy at 77, 295 and 325 K. Ab initio CASSCF calculations followed by the NEVPT2 method were applied for predicting the g-tensor components as well as Mössbauer parameters.
KW - Spin crossover
KW - Iron(III) complexes
KW - Mössbauer spectroscopy
KW - ESR spectroscopy
KW - Ab initio calculations
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-634061
DO - https://doi.org/10.3390/magnetochemistry11050043
SN - 2312-7481
VL - 11
IS - 5
SP - 1
EP - 9
PB - MDPI
CY - Basel
AN - OPUS4-63406
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Schwibbert, Karin
A1 - de Eulate Pérez, Elisa García
A1 - Wen, Keqing
A1 - Voss, Heike
A1 - Thiele, Dorothea
A1 - Richter, Anja M.
A1 - Bonse, Jörn
T1 - Escherichia coli repellence via laser-induced periodic surface structures (LIPSS) on titanium: Critical role of biofilm-associated gene expression
N2 - The inconsistency in the observed bacteria-repellent effects of laser-induced surface textures remains a subject of scientific debates. With E. coli TG1 as test strain, we performed biofilm formation assays on ultrashort pulse laser textured titanium. Samples covered with low spatial frequency LIPSS (LSFL) of periods around 750 nm or with high spatial frequency LIPSS (HSFL) featuring smaller periods around 100 nm were processed on polished samples. While LSFL significantly reduce the number of adhering bacteria compared to the polished reference, HSFL do not. Simultaneously, we concentrate our study on bacterial strategies employed for biofilm formation, that is the transcription of the biofilm-associated genes csgB, involved in primary adhesion to a surface, and wza, participating in biofilm maturation. Promoter regions of these genes were cloned into a promotor probe plasmid with the green fluorescent protein GFP+ as reporter and transferred into the test strain. As indicated by the fluorescence intensity of the reporter protein, among the bacteria colonizing LSFL-covered areas, a markedly higher proportion of cells transcribing csgB or wza were detected, compared to the bacterial populations colonizing the polished or HSFL-covered areas. To our knowledge, this is the first study indicating that the antifouling effect of LSFL topographies can be counteracted when bacteria activate biofilm-associated genes.
KW - Laser-induced periodic surface structures (LIPSS)
KW - Titanium
KW - Biofilm
KW - Antifouling
KW - Gene expression
KW - Fluorescence microscopy
PY - 2026
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655572
DO - https://doi.org/10.1016/j.apsusc.2026.166363
SN - 0169-4332
VL - 730
SP - 1
EP - 9
PB - Elsevier B.V.
AN - OPUS4-65557
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -
TY - JOUR
A1 - Lu, Xin
A1 - Hicke, Konstantin
T1 - Error suppression in wavelength scanning coherent optical time domain reflectometry by polarization diversity detection
N2 - Wavelength scanning coherent optical time domain reflectometry (WS-COTDR) is a popular distributed fiber sensing technique that quantifies environmental changes based on the frequency shift of Rayleigh reflection spectra which are usually obtained by cross correlation. This method can cause large errors due to the spikes in the spectrum caused by the random interference of the Rayleigh backscattered light and the uncorrelated section in the reflection spectrum. Polarization diversity detection is applied to suppress this type of error. Two orthogonally polarized components of the Rayleigh backscattered light are detected in a single sensing system and processed separately by cross correlation. The correlation spectra of the two polarizations are averaged to determine the frequency shift, effectively mitigating the large error. Meanwhile, the polarization dependence helps avoid the large errors caused by Fresnel reflection and restrain null sensitivity positions, where the frequency shift is difficult to be determined due to the similarity of the spectra. The sensing performance improvement is experimentally validated, and the proposed system is tested in the field to monitor traffic along a busy street in Berlin, demonstrating its functionality and feasibility in practice.
KW - Traffic monitoring
KW - Coherent optical time domain reflectometry
KW - Distributed fiber sensing
KW - Polarization diversity detection
KW - Optical fiber sensing
PY - 2025
UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-630320
DO - https://doi.org/10.1016/j.measurement.2025.117733
SN - 1873-412X
VL - 253
SP - 1
EP - 11
PB - Elsevier Ltd.
AN - OPUS4-63032
LA - eng
AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany
ER -