TY - JOUR A1 - Wegner, Karl David A1 - Resch-Genger, Ute T1 - The 2023 Nobel Prize in Chemistry: Quantum dots N2 - The 2023 Nobel Prize in Chemistry was awarded to Aleksey I. Ekimov (prize share 1/3), Louis E. Brus (prize share 1/3), and Moungi G. Bawendi (prize share 1/3) for groundbreaking inventions in the field of nanotechnology, i.e., for the discovery and synthesis of semiconductor nanocrystals, also termed quantum dots, that exhibit size-dependent physicochemical properties enabled by quantum size effects. This feature article summarizes the main milestones of the discoveries and developments of quantum dots that paved the road to their versatile applications in solid-state lighting, display technology, energy conversion, medical diagnostics, bioimaging, and image-guided surgery. KW - Quantum dots KW - Semiconductor nanocrystals KW - Luminescence KW - Quantitative spectroscopy KW - Quantum yield KW - Advanced nanomaterials KW - Quality assurance KW - Energy transfer PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597843 DO - https://doi.org/10.1007/s00216-024-05225-9 VL - 2024 SP - 1 EP - 11 PB - Springer CY - Cham AN - OPUS4-59784 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silvestroni, L. A1 - Kupsch, Andreas A1 - Müller, B. R. A1 - Ulbricht, Alexander A1 - Wieder, Frank A1 - Fritsch, Tobias A1 - Sciti, D. A1 - Bruno, Giovanni T1 - Determination of short carbon fiber orientation in zirconium diboride ceramic matrix composites N2 - In fiber-reinforced components, the fiber alignment and orientation have paramount influence on the thermomechanical properties of the resulting composite, for both short and continuous fiber. Here we present the case of an ultra-refractory matrix intended for extreme environment applications, ZrB2, reinforced with 20 vol% and 50 vol% short carbon fibers. In both cases, fibers tend to align perpendicular to the uniaxial pressure applied during shaping and sintering of a pellet, although the fiber tilt across the pellet thickness is difficult to determine. Moreover, for high volume fractions of reinforcement, the spatial distribution of the fibers is heterogeneous and tends to have domains of preferential orientations. We compare the information on the fiber distribution as collected by scanning electron microscopy images, X-ray computed tomography and synchrotron X-ray refraction radiography (SXRR). The three techniques prove to be complementary. Importantly, we demonstrate that SXRR yields the most statistically significant information due to the largest field of view, yet with a sensitivity down to the nanometer, and that can be successfully applied also to heavy matrix materials, such as zirconium boride. KW - Ceramic matrix composites KW - Synchrotron X-ray refraction radiography KW - X-ray computed tomography KW - Scanning electron microscopy KW - High-temperature ceramics PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597712 DO - https://doi.org/10.1016/j.jeurceramsoc.2024.02.048 SN - 0955-2219 VL - 44 IS - 8 SP - 4853 EP - 4862 PB - Elsevier Ltd. CY - Amsterdam AN - OPUS4-59771 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kricheldorf, Hans R. A1 - Weidner, Steffen T1 - Ring-ring equilibration (RRE) of cyclic poly(L-lactide)s by means of cyclic tin catalysts N2 - With 2,2-dibutyl-2-stanna-1,3-dithiolane (DSTL) and 2-stanna-1,3-dioxa-4,5,6,7-dibenzoxepane (SnBiPh) as catalysts ring-expansion polymerizations (REP) were performed either in 2 M solution using three different solvents and two different temperatures or in bulk at 140 and 120 ◦C. A kinetically controlled rapid REP up to weight average molecular masses (Mẃs) above 300 000 was followed by a slower degradation of the molecular masses at 140 ◦C, but not at 120 ◦C Furthermore, a low molecular mass cyclic poly(L-lactide) (cPLA) with a Mn around 16 000 was prepared by polymerization in dilute solution and used as starting material for ring-ring equilibration at 140 ◦C in 2 M solutions. Again, a decrease of the molecular mass was detectable, suggesting that the equilibrium Mn is below 5 000. The degradation of the molecular masses via RRE was surprisingly more effective in solid cyclic PLA than in solution, and a specific transesterification mechanism involving loops on the surface of crystallites is proposed. This degradation favored the formation of extended-ring crystallites, which were detectable by a “saw-tooth pattern” in their MALDI mass spectra. KW - Organic Chemistry KW - Polymers and Plastics KW - MALDI-TOF MS KW - Materials Chemistry PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593819 DO - https://doi.org/10.1016/j.eurpolymj.2024.112765 SN - 0014-3057 VL - 206 SP - 1 EP - 8 PB - Elsevier B.V. AN - OPUS4-59381 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Potopnyk, M. A1 - Mech-Piskorz, J. A1 - Angulo, G. A1 - Ceborska, M. A1 - Luboradzki, R. A1 - Andresen, Elina A1 - Gajek, A. A1 - Wisniewska, A. A1 - Resch-Genger, Ute T1 - Aggregation/Crystallization-Induced Emission in Naphthyridine-Based Carbazolyl-Modified Donor-Acceptor Boron Dyes Tunable by Fluorine Atoms N2 - Four donor-acceptor boron difluoride complexes based on the carbazole electron donor and the [1,3,5,2]oxadiazaborinino[3,4-a][1,8]naphthyridine acceptor were designed, synthesized, and systematically spectroscopically investigated in solutions, in the solid states, and dye-doped polymer films. The dyes exhibit an intense blue to red solid-state emission with photoluminescence quantum yields of up to 56% in pure dye samples and 86% in poly(methyl methacrylate) films. All boron complexes show aggregation-induced emission and reversible mechanofluorochromism. The optical properties of these dyes and their solid state luminescence can be tuned by substitution pattern, i.e., the substituents at the naphthyridine unit. Exchange of CH3- for CF3-groups does not only increase the intramolecular charge transfer character, but also provides a crystallization-induced emission enhancement. KW - Spectroscopy KW - Dye KW - Luminescence KW - Sensor KW - Fluorescence KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Synthesis PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597426 DO - https://doi.org/10.1002/chem.202400004 SN - 0947-6539 SP - 1 EP - 12 PB - Wiley VHC-Verlag AN - OPUS4-59742 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Peters, Stefan A1 - Bartling, Stephan A1 - Parlinska-Wojtan, Magdalena A1 - Wotzka, Alexander A1 - Guilherme Buzanich, Ana A1 - Wohlrab, Sebastian A1 - Abdel-Mageed, Ali M. T1 - Stabilization of intermediate Mo oxidation states by Nb doping enhancing methane aromatization on Mo/HZSM-5 catalysts N2 - The dehydroaromatization of methane is a promising process to produce aromatics and ultra-pure hydrogen. Increased yields and stability of Mo/HZSM-5 against irreversible deactivation were achieved via a redox interaction by doping with otherwise inert Nb. KW - General Materials Science KW - Sustainability and the Environment KW - General Chemistry KW - Renewable Energy PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597670 DO - https://doi.org/10.1039/D3TA07532J SN - 2050-7488 SP - 1 EP - 16 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59767 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 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 - 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 - Theiler, Géraldine A1 - Cano Murillo, Natalia A1 - Halder, Karabi A1 - Balasooriya, Winoj A1 - Hausberger, Andreas A1 - Kaiser, Andreas T1 - Effect of high-pressure hydrogen environment on the physical and mechanical properties of elastomers N2 - This study presents the influence of high-pressure hydrogen environment on the physical and mechanical properties of two types of cross-linked hydrogenated acrylonitrile butadiene rubbers. Based on the CSA/ANSI standard, static exposures in hydrogen experiments were performed up to 100 MPa at 120 °C. Characterization before and after exposure was conducted by means of density and hardness measurements, dynamic mechanical analysis (DMA), tensile tests, compression set, FT-IR and AFM analyses to assess effects after decompression. While the effect of high-pressure exposure is significant immediately after exposure, most of the physical and mechanical properties recover after 48 hours. FT-IR, AFM, SEM and compression set results indicate, however, permanent effects. KW - Hydrogen KW - Mechanical properties KW - Elastomers KW - High-pressure hydrogen environment PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597102 DO - https://doi.org/10.1016/j.ijhydene.2024.01.148 SN - 0360-3199 VL - 58 SP - 389 EP - 399 PB - Elsevier Ltd. AN - OPUS4-59710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asna Ashari, Parsa A1 - Blind, Knut T1 - The effects of hydrogen research and innovation on international hydrogen trade N2 - Climate change and the pressure to decarbonize, as well as energy security concerns, have drawn the attention of policymakers and the industry to hydrogen energy. To ad-vance the hydrogen economy at a global scale, research and innovation progress is of significant importance, among others. However, previous studies have provided only lim-ited quantitative evidence of the effects of research and innovation on the formation of a global hydrogen market. Instead, they postulate rather than empirically support this rela-tionship. Therefore, this study analyzes the effects of research and innovation measured by scientific publications, patents, and standards on bilateral hydrogen trade flows for 32 countries between 1995 and 2019 in a gravity model of trade, using regression analyses and Poisson Pseudo Maximum Likelihood (PPML) estimation. The main results of the PPML estimation show that research and innovation progress is indeed associated with increased trade, especially with patenting and (international) standardization enhancing hydrogen export volumes. As policy implications, we derive that increased public R&D funding can help increase the competitiveness of hydrogen energy and boost market growth, along with infrastructure support and harmonized standards and regulations. KW - Hydrogen supply KW - Global hydrogen market KW - Research and innovation KW - Push and pull effects KW - Hydrogen policies PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594875 DO - https://doi.org/10.1016/j.enpol.2023.113974 SN - 0301-4215 VL - 186 SP - 1 EP - 15 PB - Elsevier B.V. AN - OPUS4-59487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wang, Zengquan A1 - Riechers, Birte A1 - Derlet, Peter M. A1 - Maaß, Robert T1 - Atomic cluster dynamics causes intermittent aging of metallic glasses N2 - In the past two decades, numerous relaxation or physical aging experiments of metallic glasses have revealed signatures of intermittent atomic-scale processes. Revealed via intensity cross-correlations from coherent scattering using X-ray photon correlation spectroscopy (XPCS), the observed abrupt changes in the time-domain of atomic motion does not fit the picture of gradual slowing down of relaxation times and their origin continues to remain unclear. Using a binary Lennard-Jones model glass subjected to microsecond-long isotherms, we show here that temporally and spatially heterogeneous atomic-cluster activity at different length-scales drive the emergence of highly non-monotonous intensity cross-correlations. The simulated XPCS experiments reveal a variety of time-dependent intensity-cross correlations that, depending on both the structural evolution and the 𝑞-space sampling, give detailed insights into the possible structural origins of intermittent aging measured with XPCS. KW - Metallic glasses KW - Aging KW - Molecular dynamics KW - XPCS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595415 DO - https://doi.org/10.1016/j.actamat.2024.119730 SN - 1359-6454 VL - 267 SP - 1 EP - 9 PB - Elsevier B.V. CY - Amsterdam, Niederlande AN - OPUS4-59541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Karapanagiotis, Christos A1 - Schukar, Marcus A1 - Krebber, Katerina T1 - Verteilte faseroptische Sensoren zur Zustandsüberwachung von Verbundwerkstoff-Druckbehältern T1 - Distributed fiber optic sensors for structural health monitoring of composite pressure vessels N2 - In diesem Beitrag geben wir einen umfassenden Überblick über unsere Forschung auf dem Gebiet der verteilten faseroptischen Sensorik für die strukturelle Zustandsüberwachung von Wasserstoffdruckbehältern aus Verbundwerkstoffen. Insbesondere zeigen wir, wie die Integration von faseroptischen Sensoren in Druckbehälter aus Verbundwerkstoffen die Sicherheit erhöht und gleichzeitig die Wartungskosten senkt. Die geringe Größe von Lichtwellenleitern ermöglicht ihre Integration in Verbundwerkstoffstrukturen während des Herstellungsprozesses, wodurch eine kontinuierliche Überwachung sowie eine präzise Erkennung und Lokalisierung von Strukturschäden während des Betriebs der Druckbehälter ermöglicht wird. Wir erörtern auch das Potenzial modernster Signalverarbeitungsmethoden und des maschinellen Lernens für die Weiterentwicklung der vorausschauenden Instandhaltung. Die von uns vorgestellten Anwendungen von faseroptischen Sensoren zeigen, dass sie einen wichtigen Beitrag zur Energiewende hin zu erneuerbaren Energien leisten können. KW - Verteilte faseroptische Sensoren KW - Verbundwerkstoffe KW - Wasserstoff-Druckbehälter KW - Strukturüberwachung KW - Maschinelles Lernen PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-596290 DO - https://doi.org/10.1515/teme-2023-0170 SN - 0171-8096 SP - 1 EP - 12 AN - OPUS4-59629 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Emamverdi, Farnaz A1 - Huang, J. A1 - Mosane Razavi, Negar A1 - Bojdys, M. J. A1 - Forster, A. B. A1 - Budd, P. M. A1 - Böhning, Martin A1 - Schönhals, Andreas T1 - Molecular Mobility and Gas Transport Properties of Mixed Matrix Membranes Based on PIM‑1 and a Phosphinine Containing Covalent Organic Framework N2 - Polymers with intrinsic microporosity (PIMs) are gaining attention as gas separation membranes. Nevertheless, they face limitations due to pronounced physical aging. In this study a covalent organic framework containing λ5-phosphinine moieties, CPSF-EtO were incorporated as a nanofiller (concentration range 0-10 wt%) into a PIM-1 matrix forming dense films with a thickness of ca. 100 μm. The aim of the investigation was to investigate possible enhancements of gas transport properties and mitigating effects on physical aging. The incorporation of the nanofiller occurred on aggregate level with domains up to 100 nm as observed by T-SEM and confirmed by X-ray scattering. Moreover, the X-ray data show that the structure of the microporous network of the PIM-1 matrix is changed by the nanofiller. As the molecular mobility is fundamental for gas transport as well as for physical aging, the study includes dielectric investigations of pure PIM-1 and PIM-1/CPSF-EtO mixed matrix membranes to establish a correlation between the molecular mobility and the gas transport properties. Using the time-lag method the gas permeability and the permselectivity were determined for N2, O2, CH4 and CO2 for samples with variation in filler content. A significant increase in the permeability of CH4 and CO2 (50 % increase compared to pure PIM-1) was observed for a concentration of 5 wt% of the nanofiller. Furthermore, the most pronounced change in the permselectivity was found for the gas pair CO2/N2 at a filler concentration of 7 wt%. KW - Polymers of Intrinsic Microporosity KW - Nanocomposites PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595031 DO - https://doi.org/10.1021/acs.macromol.3c02419 SN - 0024-9297 VL - 57 IS - 4 SP - 1829 EP - 1845 PB - ACS Publications AN - OPUS4-59503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kromm, Arne A1 - Thomas, Maximilian A1 - Kannengiesser, Thomas A1 - Gibmeier, Jens T1 - On the interpretation of Varestraint and Transvarestraint hot cracking test results N2 - The Varestraint test and its variant Transvarestraint are one of the most widely used techniques for evaluating a material solidification cracking sensitivity during welding. The result of such tests is a crack length which is proportional to the material’s cracking susceptibility. Nevertheless, the welding and load parameters can unintentionally influence the crack length, which in some cases can distort the material evaluation. An approach is described as to how these effects can be assessed with the aid of a digital crack analysis. The crack lengths are compared position-dependently with their possible propagation due to the weld pool movement during continuous loading. The index derived from this can be used by the operator to evaluate his test parameters. In addition, a comparison of the results of different Varestraint setups is made possible. Alongside experimental results, a numerical sensitivity analysis is presented on how individual welding and loading parameters can affect the crack lengths. KW - Varestraint test KW - Solidification cracking KW - Weldability PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595089 DO - https://doi.org/10.1007/s40194-024-01706-8 SN - 0043-2288 SP - 1 EP - 13 PB - Springer Science and Business Media LLC AN - OPUS4-59508 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mansurova, Maria A1 - Johann, Sergej A1 - Kohlhoff, Harald A1 - Rurack, Knut A1 - Bartholmai, Matthias A1 - Bell, Jérémy T1 - On-Site Analytical Tool Based on Crude Oil Fluorescence and Chemometrics for the Rapid Determination of the Nature and Essential Properties of Oil Spills N2 - With the reduction of large oil spills because of stricter regulations and safety measures, the question of how to manage smaller oil spills arises. Few on-site analytical tools are available for first responders or other law enforcement personnel to rapidly test for crude oil in the early management of localized polluted areas. The approach reported here relies on well-described computer-assisted multivariate data analysis of the intrinsic fluorescence fingerprints of crude oils to build a multivariate model for the rapid classification of crude oils and the prediction of their properties. Thanks to a dedicated robust portable reader, the method allowed classification and accurate prediction of various properties of crude oil samples like density (according to API, the American Petroleum Institute and viscosity as well as composition parameters such as volume fractions of paraffins or aromatics. In this way, autonomous operation in on-site or in-the-field applications becomes possible based on the direct (undiluted and untreated) measurement of samples and a rapid, tablet-operated readout system to yield a robust and simple analytical test with superior performance. Testing in real-life scenarios allowed the successful classification and prediction of a number of oil spill samples as well as weathered samples that closely resemble samples collected by first responders. KW - Oil spills KW - Fluorescence KW - PCA KW - Petroleum KW - Rapid test KW - Portable PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595442 DO - https://doi.org/10.1021/acsestwater.3c00648 VL - 4 IS - 2 SP - 621 EP - 627 PB - American Chemical Society (ACS) AN - OPUS4-59544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - von Törne, Wipert Jannik A1 - Klyk-Seitz, Urszula-Anna A1 - Piechotta, Christian T1 - Developing a GC-EI-MS/MS method for quantifying warfarin and five hydroxylated metabolites generated by the Fenton reaction N2 - AbstractSince the 1950s, Warfarin has been used globally as both a prescription drug and a rodenticide. Research has shown that warfarin and other rodenticides are present in the environment and food chain. However, emerging contaminants are subject to degradation by biotic and abiotic processes and advanced oxidation processes. In some cases, detecting the parent compound may not be possible due to the formation of structurally changed species. This approach aims to identify hydroxylated transformation products of warfarin in a laboratory setting, even after the parent compound has undergone degradation. Therefore, the Fenton reaction is utilized to insert hydroxylation into the parent compound, warfarin, by hydroxyl and hydroperoxyl radicals generated by Fe2+/Fe3+ redox reaction with hydrogen peroxide. Using multiple reaction monitoring, a GC–MS/MS method, incorporating isotopically labeled reference compounds, is used to quantify the expected derivatized species. The analytes are derivatized using trimethyl-3-trifluoromethyl phenyl ammonium hydroxide, and the derivatization yield of warfarin is determined by using isotopically labeled reference compounds. The method has a linear working range of 30 to 1800 ng/mL, with detection limits ranging from 18.7 to 67.0 ng/mL. The analytes are enriched using a C18-SPE step, and the recovery for each compound is calculated. The Fenton reaction generates all preselected hydroxylated transformation products of warfarin. The method successfully identifies that 4′-Me-O-WAR forms preferentially under the specified experimental conditions. By further optimizing the SPE clean-up procedures, this GC–MS-based method will be suitable for detecting transformation products in more complex matrices, such as environmental water samples. Overall, this study provides a better understanding of warfarin’s degradation and offers a robust analytical tool for investigating its transformation products. KW - Health, Toxicology and Mutagenesis KW - Pollution KW - Environmental Chemistry KW - General Medicine PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595737 DO - https://doi.org/10.1007/s11356-024-32133-3 SN - 0944-1344 VL - 31 SP - 16986 EP - 16994 PB - Springer Science and Business Media LLC AN - OPUS4-59573 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rhode, Michael A1 - Erxleben, Kjell A1 - Richter, Tim A1 - Schroepfer, Dirk A1 - Mente, Tobias A1 - Michael, Thomas T1 - Local mechanical properties of dissimilar metal TIG welded joints of CoCrFeMnNi high entropy alloy and AISI 304 austenitic steel N2 - Multiple principal element alloys encompass the well-known high entropy alloys (HEA). The alloy system represents a new class of materials consisting of at least three alloying elements, each containing 5 to 35 at.%. Thus, this alloying concept differs fundamentally from conventional materials such as steel or nickel alloys. For this purpose, the alloying elements are specifically selected, the microstructures are adjusted in a single-phase and, in some cases, multi-phase manner. In particular, conflicting goals, such as the trade-off between strength and ductility in conventional steels, are overcome. However, in the last 20 years, the focus has been on material synthesis. With the increase in available material quantities, the focus is now on processing issues such as joining and welding processes. The weldability of HEAs has received very little attention so far. The experience with dissimilar metal welds is completely lacking but is essential for the application of these materials in combination with conventional materials. The present study presents comprehensive experimental results on the weldability of an equimolar CoCrFeMnNi-HEA in cold-rolled and heat-treated condition, which was joined by tungsten inert gas welding to an austenitic steel AISI 304. The mechanical properties of the dissimilar metal welds were characterized by cross-weld tensile samples, whereas the local deformation in the weld of the different welding zones was measured by digital image correlation. In accordance with the respective initial HEA condition (cold-rolled vs. heat-treated), the local strain behavior was divergent and influenced the global mechanical properties of both DMW types. Nonetheless, the experiments provided proof in principle of the weldability for dissimilar joints of the CoCrFeMnNi-HEA welded to conventional materials like austenitic stainless steels ensuring a corresponding capability for mechanical loading. This allows further considerations on the application of these innovative materials. KW - TIG welding KW - High-entropy alloys KW - Mechanical properties KW - Dissimilar metal weld PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595775 DO - https://doi.org/10.1007/s40194-024-01718-4 SN - 0043-2288 SP - 1 EP - 11 PB - Springer Science and Business Media LLC AN - OPUS4-59577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prabitz, Konstantin Manuel A1 - Antretter, Thomas A1 - Rethmeier, Michael A1 - El-Sari, Bassel A1 - Schubert, Holger A1 - Hilpert, Benjamin A1 - Gruber, Martin A1 - Sierlinger, Robert A1 - Ecker, Werner T1 - Numerical and experimental assessment of liquid metal embrittlement in externally loaded spot welds N2 - Zinc-based surface coatings are widely applied with high-strength steels in automotive industry. Some of these base materials show an increased brittle cracking risk during loading. It is necessary to examine electrogalvanized and uncoated samples of a high strength steel susceptible to liquid metal embrittlement during spot welding with applied external load. Therefore, a newly developed tensile test method with a simultaneously applied spot weld is conducted. A fully coupled 3D electrical, thermal, metallurgical and mechanical finite element model depicting the resistant spot welding process combined with the tensile test conducted is mandatory to correct geometric influences of the sample geometry and provides insights into the sample’s time dependent local loading. With increasing external loads, the morphology of the brittle cracks formed is affected more than the crack depth. The validated finite element model applies newly developed damage indicators to predict and explain the liquid metal embrittlement cracking onset and development as well as even ductile failure. KW - Resistance spot welding KW - Finite element simulation KW - Advanced high-strength steel KW - Liquid metal embrittlement KW - Damage prediction KW - Tensile resistance spot welding experiment PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594848 DO - https://doi.org/10.1007/s40194-024-01696-7 SN - 0043-2288 SP - 1 EP - 10 PB - Springer Science and Business Media LLC AN - OPUS4-59484 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 - Zhang, Kun A1 - Carrod, Andrew J. A1 - Del Giorgio, Elena A1 - Hughes, Joseph A1 - Rurack, Knut A1 - Bennet, Francesca A1 - Hodoroaba, Vasile-Dan A1 - Harrad, Stuart A1 - Pikramenou, Zoe T1 - Luminescence Lifetime-Based Sensing Platform Based on Cyclometalated Iridium(III) Complexes for the Detection of Perfluorooctanoic Acid in Aqueous Samples N2 - Luminescence lifetimes are an attractive analytical method for detection due to its high sensitivity and stability. Iridium probes exhibit luminescence with long excited-state lifetimes, which are sensitive to the local environment. Perfluorooctanoic acid (PFOA) is listed as a chemical of high concern regarding its toxicity and is classified as a “forever chemical”. In addition to strict limits on the presence of PFOA in drinking water, environmental contamination from industrial effluent or chemical spills requires rapid, simple, accurate, and cost-effective analysis in order to aid containment. Herein, we report the fabrication and function of a novel and facile luminescence sensor for PFOA based on iridium modified on gold surfaces. These surfaces were modified with lipophilic iridium complexes bearing alkyl chains, namely, IrC6 and IrC12, and Zonyl-FSA surfactant. Upon addition of PFOA, the modified surfaces IrC6-FSA@Au and IrC12-FSA @Au show the largest change in the red luminescence signal with changes in the luminescence lifetime that allow monitoring of PFOA concentrations in aqueous solutions. The platform was tested for the measurement of PFOA in aqueous samples spiked with known concentrations of PFOA and demonstrated the capacity to determine PFOA at concentrations >100 μg/L (240 nM). KW - Perfluorooctanoic Acid (PFOA) KW - Cyclometalated iridium (III) complexes KW - Luminescent lifetime KW - Optically active surfaces KW - ToF-SIMS PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594535 UR - https://pubs.acs.org/doi/10.1021/acs.analchem.3c04289 DO - https://doi.org/10.1021/acs.analchem.3c04289 VL - 96 IS - 4 SP - 1565 EP - 1575 PB - American Chemical Society (ACS) AN - OPUS4-59453 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Weidner, Steffen A1 - Meyer, A. A1 - Kricheldorf, H. T1 - Transformation of poly(L-lactide) crystals composed of linear chains into crystals composed of cycles N2 - A poly(L-lactide) with a trifluoroethyl ester end group and an average degree of polymerization (DP) of 50 was synthesized by ROP of L-lactide initiated with trifluoroethanol. Small-angle X-ray scattering (SAXS) in combination with differential scanning calorimetry (DSC) measurements revealed an average crystal thickness of 13 nm, corresponding to 45 repeat units. This suggests that most crystallites were formed by extended PLA chains, and both flat surfaces were covered by CF3 groups. The crystalline PLAs were annealed at 140 or 160 °C in the presence of two catalysts: tin(II) 2-ethylhexanoate, (SnOct2) or dibutyltin bis(pentafluorophenoxide) (BuSnPhF). The chemical reactions, such as polycondensation and cyclization, proceeded in the solid state and were monitored by matrix-assisted laser desorption/ionization time-offlight (MALDI TOF) mass spectrometry and gel permeation chromatography (GPC) measurements. Under optimal conditions a large fraction of linear chains was transformed into crystallites composed of extended cycles. Additionally, MALDI TOF MS analysis of GPC fractions from samples annealed for 28 or 42 days detected chain elongation of the linear species up to a factor of 20. KW - Polylactide KW - MALDI-TOF MS KW - Crystalinity KW - Transesterification PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597250 DO - https://doi.org/10.1039/D3PY01370G SN - 1759-9954 VL - 15 IS - 12 SP - 1173 EP - 1181 PB - Royal Society for Chemistry AN - OPUS4-59725 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brockmann, N. A1 - Sicken, A. A1 - Krüger, Jörg T1 - Effects of laser cleaning on the condition of different silk model samples using varying wavelengths and pulse durations N2 - The cleaning of aged silk fibers poses a common challenge in the conservation of textiles, since traditional cleaning techniques often yield unsatisfactory results or even harm objects. In this regard, cleaning objects with laser radiation is a promising addition to the range of available methods. Due to it being contactless, even brittle and touch-sensitive objects with disfiguring or harmful soiling could potentially be cleaned and therefore made accessible for research and presentation. Examples of treatment have sometimes shown spectacular results. Still there is some skepticism concerning the safety of this treatment for textile materials, which has been strengthened through previous 532 nm wavelength nanosecond laser cleaning studies on silk fibers. Taking these published results into account, the range of examined laser parameters has been extended in this study, from 532 nm nanosecond laser to 1064 nm nanosecond and even 800 nm femtosecond laser, reevaluating the effect of this treatment on the fibers. The physicochemical processes taking place on the silk fibers when cleaning with lasers are complex and still not fully understood. The aim of this project was therefore to bring more clarification about potential effects of those processes on the condition of silk samples treated with a set of different parameters for wavelength, pulse duration, energy density and number of pulses per spot. It also looks at the influence of the presence of soiling on the results. The analysis of potential effects was then carried out using statistical methods and advanced analytics. Scanning electron microscopy, Fourier-transform infrared spectroscopy and colorimetry technology provided the required insights to better assess the effects. Results show that laser cleaning of silk fibers, like most other conventional cleaning techniques, is not completely without risk, but knowing what the possible effects are helps making decisions on whether the benefits of the technique used justify these risks. KW - Laser cleaning KW - Cultural heritage KW - Conservation KW - Silk PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594601 DO - https://doi.org/10.1186/s40494-024-01152-1 SN - 2050-7445 VL - 12 IS - 1 SP - 1 EP - 15 PB - Springer AN - OPUS4-59460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stawski, Tomasz A1 - Karafiludis, Stephanos A1 - Pimentel, Carlos A1 - Montes-Hernández, German A1 - Kochovski, Zdravko A1 - Bienert, Ralf A1 - Weimann, Karin A1 - Emmerling, Franziska A1 - Scoppola, Ernesto A1 - Van Driessche, Alexander E.S. T1 - Solution-driven processing of calcium sulfate: The mechanism of the reversible transformation of gypsum to bassanite in brines N2 - Here, we show that calcium sulfate dihydrate (gypsum) can be directly, rapidly and reversibly converted to calcium sulfate hemihydrate (bassanite) in high salinity solutions (brines). The optimum conditions for the efficient production of bassanite in a short time (<5 min) involve the use of brines with c(NaCl) > 4 M and maintaining a temperature, T > 80 °C. When the solution containing bassanite crystals is cooled down to around room temperature, eventually gypsum is formed. When the temperature is raised again to T > 80 °C, bassanite is rapidly re-precipitated. This contrasts with the better-known behaviour of the bassanite phase in low-salt environments. In low-salinity aqueous solutions, bassanite is considered to be metastable with respect to gypsum and anhydrite, and therefore gypsum-to-bassanite conversion does not occur in pure water. Interestingly, the high-salinity transformation of gypsum-to-bassanite has been reported by many authors and used in practice for several decades, although its very occurrence actually contradicts numerical thermodynamic predictions regarding solubility of calcium sulfate phases. By following the evolution of crystalline phases with in situ and time-resolved X-ray diffraction/scattering and Raman spectroscopy, we demonstrated that the phase stability in brines at elevated temperatures was inaccurately represented in the thermodynamic databases. Most notably for c(NaCl) > 4 M, and T > 80 °C gypsum becomes readily more soluble than bassanite, which induces the direct precipitation of the latter from gypsum. The fact that these transformations are controlled by the solution provides extensive opportunities for precise manipulation of crystal formation. Our experiments confirmed that bassanite remained the sole crystalline phase for many hours before reverting into gypsum. This property is extremely advantageous for practical processing and efficient crystal extraction in industrial scenarios. KW - Industrial and Manufacturing Engineering KW - Strategy and Management KW - General Environmental Science KW - Renewable Energy, Sustainability and the Environment KW - Building and Construction KW - Calcium sulfate KW - Gypsum KW - Bassanite KW - Scattering KW - Raman KW - In situ KW - Synchrotron KW - BESSY KW - MySpot PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594698 UR - https://www.sciencedirect.com/science/article/pii/S0959652624004591#appsec1 DO - https://doi.org/10.1016/j.jclepro.2024.141012 SN - 0959-6526 VL - 440 SP - 1 EP - 12 PB - Elsevier B.V. AN - OPUS4-59469 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mrkwitschka, Paul A1 - Rühle, Bastian A1 - Kuchenbecker, Petra A1 - Löhmann, Oliver A1 - Lindemann, Franziska A1 - Hodoroaba, Vasile-Dan T1 - Embedding and cross-sectioning as a sample preparation procedure for accurate and representative size and shape measurement of nanopowders N2 - Reliable measurement of the size of polydisperse, complex-shaped commercial nanopowders is a difficult but necessary task, e.g., for regulatory requirements and toxicity risk assessment. Suitable methods exist for the accurate characterization of the size of non-aggregated, stabilized, spherical and monodisperse nanoparticles. In contrast, industrial nanoscale powders usually require dedicated sample preparation procedures developed for the analysis method of choice. These nano-powders tend to agglomerate and/or aggregate, a behavior which in combination with an innate broad particle size distribution and irregular shape often significantly alters the achievable accuracy of the measured size parameters. The present study systematically tests two commercially available nanoscale powders using different sample preparation methods for correlative analysis by scanning electron microscopy, dynamic light scattering, Brunauer–Emmet–Teller method and differential mobility analysis. One focus was set on the sample preparation by embedding nanoparticles in carbon-based hot-mounting resin. Literature on this topic is scarce and the accuracy of the data extracted from cross sections of these particles is unclearly stated. In this paper systematic simulations on the deviation of the size parameters of well-defined series of nanoparticles with different shapes from the nominal value were carried out and the contributing factors are discussed. KW - Nanopowder KW - Electron microscopy KW - Sample preparation KW - Cross-sectioning KW - Cerium oxide KW - Zinc oxide PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593289 DO - https://doi.org/10.1038/s41598-023-51094-0 SN - 2045-2322 VL - 14 SP - 1 EP - 10 PB - Springer Nature CY - London AN - OPUS4-59328 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Asna Ashari, Parsa A1 - Oh, Hyochan A1 - Koch, Claudia T1 - Pathways to the hydrogen economy: A multidimensional analysis of the technological innovation systems of Germany and South Korea N2 - The global trend towards decarbonization and the demand for energy security have put hydrogen energy into the spotlight of industry, politics, and societies. Numerous governments worldwide are adopting policies and strategies to facilitate the transition towards hydrogen-based economies. To assess the determinants of such transition, this study presents a comparative analysis of the technological innovation systems (TISs) for hydrogen technologies in Germany and South Korea, both recognized as global frontrunners in advancing and implementing hydrogen-based solutions. By providing a multidimensional assessment of pathways to the hydrogen economy, our analysis introduces two novel and crucial elements to the TIS analysis: (i) We integrate the concept of ‘quality infrastructure’ given the relevance of safety and quality assurance for technology adoption and social acceptance, and (ii) we emphasize the social perspective within the hydrogen TIS. To this end, we conducted 24 semi-structured expert interviews, applying qualitative open coding to analyze the data. Our results indicate that the hydrogen TISs in both countries have undergone significant developments across various dimensions. However, several barriers still hinder the further realization of a hydrogen economy. Based on our findings, we propose policy implications that can facilitate informed policy decisions for a successful hydrogen transition. KW - Hydrogen economy KW - Technological innovation system KW - Quality infrastructure KW - Multidimensional technology adoption KW - Social acceptance PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593312 DO - https://doi.org/10.1016/j.ijhydene.2023.08.286 IS - Volume 49, Part D SP - 405 EP - 421 PB - Elsevier AN - OPUS4-59331 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Alekseychuk, V. O. A1 - Kupsch, Andreas A1 - Plotzki, D. A1 - Bellon, Carsten A1 - Bruno, Giovanni T1 - Simulation-Assisted Augmentation of Missing Wedge and Region-of-Interest Computed Tomography Data N2 - This study reports a strategy to use sophisticated, realistic X-ray Computed Tomography (CT) simulations to reduce Missing Wedge (MW) and Region-of-Interest (RoI) artifacts in FBP (Filtered Back-Projection) reconstructions. A 3D model of the object is used to simulate the projections that include the missing information inside the MW and outside the RoI. Such information augments the experimental projections, thereby drastically improving the reconstruction results. An X-ray CT dataset of a selected object is modified to mimic various degrees of RoI and MW problems. The results are evaluated in comparison to a standard FBP reconstruction of the complete dataset. In all cases, the reconstruction quality is significantly improved. Small inclusions present in the scanned object are better localized and quantified. The proposed method has the potential to improve the results of any CT reconstruction algorithm. KW - Computed tomography KW - Missing wedge KW - Region of interest KW - Augmented data KW - CT simulation KW - aRTist PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593799 UR - https://www.mdpi.com/2313-433X/10/1/11 DO - https://doi.org/10.3390/jimaging10010011 SN - 2313-433X VL - 10 IS - 1 SP - 1 EP - 15 PB - MDPI CY - Basel AN - OPUS4-59379 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zia, Ghezal Ahmad Jan A1 - Hanke, Thomas A1 - Skrotzki, Birgit A1 - Völker, Christoph A1 - Bayerlein, Bernd T1 - Enhancing Reproducibility in Precipitate Analysis: A FAIR Approach with Automated Dark-Field Transmission Electron Microscope Image Processing N2 - AbstractHigh-strength aluminum alloys used in aerospace and automotive applications obtain their strength through precipitation hardening. Achieving the desired mechanical properties requires precise control over the nanometer-sized precipitates. However, the microstructure of these alloys changes over time due to aging, leading to a deterioration in strength. Typically, the size, number, and distribution of precipitates for a quantitative assessment of microstructural changes are determined by manual analysis, which is subjective and time-consuming. In our work, we introduce a progressive and automatable approach that enables a more efficient, objective, and reproducible analysis of precipitates. The method involves several sequential steps using an image repository containing dark-field transmission electron microscopy (DF-TEM) images depicting various aging states of an aluminum alloy. During the process, precipitation contours are generated and quantitatively evaluated, and the results are comprehensibly transferred into semantic data structures. The use and deployment of Jupyter Notebooks, along with the beneficial implementation of Semantic Web technologies, significantly enhances the reproducibility and comparability of the findings. This work serves as an exemplar of FAIR image and research data management. KW - Industrial and Manufacturing Engineering KW - General Materials Science KW - Automated image analysis KW - FAIR research data management KW - Reproducibility KW - microstructural changes PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593905 DO - https://doi.org/10.1007/s40192-023-00331-5 SN - 2193-9772 SP - 1 EP - 15 PB - Springer Science and Business Media LLC CY - Heidelberg AN - OPUS4-59390 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zuffa, Caterina A1 - Cappuccino, Chiara A1 - Casali, Lucia A1 - Emmerling, Franziska A1 - Maini, Lucia T1 - Liquid reagents are not enough for liquid assisted grinding in the synthesis of (AgBr)(n-pica) n N2 - This study investigates the mechanochemical reactions between AgBr 3-picolylamine and 4-picolylamine. The use of different stoichiometry ratios of the reagents allows [(AgBr)(n-pica)]n and [(AgBr)2(n-pica)]n to be obtained, and we report the new structures of [(AgBr)2(3-pica)]n and [(AgBr)2(4-pica)]n which are characterized by the presence of the following: (a) infinite inorganic chains, (b) silver atom coordinated only by bromide atoms and (c) argentophilic interactions. Furthermore, we studied the interconversion of [(AgBr)(n-pica)]n/[(AgBr)2(n-pica)]n by mechanochemical and thermal properties. The in situ experiments suggest that [(AgBr)(3-pica)]n is kinetically favoured while [(AgBr)2(3-pica)]n is converted into [(AgBr)(3-pica)]n only with a high excess of the ligand. Finally, the liquid nature of the ligands is not sufficient to assist the grinding process, and the complete reaction is observed with the addition of a small quantity of acetonitrile. KW - Mechanochemistry KW - Complex PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594755 DO - https://doi.org/10.1039/d3cp04791a SN - 1463-9076 SP - 1 EP - 10 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59475 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schwarz, I. A1 - Rieck, Arielle A1 - Mehmood, Asad A1 - Bublitz, R. A1 - Bongers, L. A1 - Weuster-Botz, D. A1 - Fellinger, Tim-Patrick T1 - PEM Electrolysis in a Stirred-Tank Bioreactor Enables Autotrophic Growth of Clostridium ragsdalei with CO2 and Electrons N2 - Acetogenic bacteria produce CO2-based chemicals in aqueous media by hydrogenotrophic conversion of CO2, but CO is the preferred carbon and electron source. Consequently, coupling CO2 electrolysis with bacterial fermentation within an integrated bio-electrocatalytical system (BES) is promising, if CO2 reduction catalysts are available for the generation of CO in the complex biotic electrolyte. A standard stirred-tank bioreactor was coupled to a zero-gap PEM electrolysis cell for CO2 conversion, allowing voltage control and separation of the anode in one single cell. The cathodic CO2 reduction and the competing hydrogen evolution enabled in-situ feeding of C. ragsdalei with CO and H2. Proof-of-concept was demonstrated in first batch processes with continuous CO2 gassing, as autotrophic growth and acetate formation was observed in the stirred BES in a voltage range of −2.4 to −3.0 V. The setup is suitable also for other bioelectrocatalytic reactions. Increased currents and lower overvoltages are however required. Atomically-dispersed M−N−C catalysts show promise, if degradation throughout autoclaving can be omitted. The development of selective and autoclavable catalysts resistant to contamination and electrode design for the complex electrolyte will enable efficient bioelectrocatalytic power-to-X systems based on the introduced BES. KW - Energy Conversion PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594766 DO - https://doi.org/10.1002/celc.202300344 SN - 2196-0216 SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-59476 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quackatz, Lukas A1 - Griesche, Axel A1 - Nietzke, Jonathan A1 - Kannengießer, Thomas T1 - In situ measurement of hydrogen concentration in steel using laser‑induced breakdown spectroscopy (LIBS) N2 - The ISO 3690 standard “Determination of hydrogen content in arc weld metal” requires a thermal activation of the diffusible hydrogen in a piece of weld metal for the subsequent ex situ concentration measurement by carrier gas hot extraction CGHE or thermal desorption spectroscopy (TCD). Laser-induced breakdown spectroscopy (LIBS) offers a time and spatially resolved, almost non-destructive, in situ measurement of hydrogen at surfaces without sample preparation. We measured hydrogen in steels, which were charged either electrochemically or by high-pressure hydrogen gas, and compared the results. Further, the feasibility of quantitative hydrogen line scan measurements with LIBS was demonstrated by measuring hydrogen at water jet cut surfaces. The hydrogen concentrations measured with the help of LIBS were compared with CGHE measurements. It was observed that hydrogen can be reliably measured with LIBS for concentrations larger than 2 wt.-ppm. The maximum hydrogen concentration achieved using electrochemical charging was 85.1 ppm. The results show that LIBS is a promising technique for time- and spatially resolved measurements of hydrogen in steels. T2 - IIW Annual Assembly 2023 CY - Singapore KW - LIBS KW - Hydrogen measurement KW - Welding KW - Stainless steel KW - Diffusible hydrogen PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593664 DO - https://doi.org/10.1007/s40194-023-01677-2 SP - 1 EP - 9 PB - Springer AN - OPUS4-59366 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böllinghaus, Thomas A1 - Cross, Carl T1 - Obituary: Prof. Dr.-Ing. Hans Hoffmeister N2 - On November 3, 2023, our dear colleague, Prof. Dr.-Ing. Hans Hoffmeister, born in 1932 in Kassel, Germany, passed away in Ahrensburg, near Hamburg, Germany. KW - Metals and Alloys KW - Mechanical Engineering KW - Mechanics of Materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594160 DO - https://doi.org/10.1007/s40194-023-01675-4 SP - 1 EP - 2 PB - Springer Science and Business Media LLC AN - OPUS4-59416 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bayerlein, Bernd A1 - Schilling, Markus A1 - Birkholz, Henk A1 - Jung, Matthias A1 - Waitelonis, Jörg A1 - Mädler, Lutz A1 - Sack, Harald T1 - PMD Core Ontology: Achieving semantic interoperability in materials science N2 - Knowledge representation in the Materials Science and Engineering (MSE) domain is a vast and multi-faceted challenge: Overlap, ambiguity, and inconsistency in terminology are common. Invariant (consistent) and variant (context-specific) knowledge are difficult to align cross-domain. Generic top-level semantic terminology often is too abstract, while MSE domain terminology often is too specific. In this paper, an approach how to maintain a comprehensive MSE-centric terminology composing a mid-level ontology–the Platform MaterialDigital Core Ontology (PMDco)–via MSE community-based curation procedures is presented. The illustrated findings show how the PMDco bridges semantic gaps between high-level, MSE-specific, and other science domain semantics. Additionally, it demonstrates how the PMDco lowers development and integration thresholds. Moreover, the research highlights how to fuel it with real-world data sources ranging from manually conducted experiments and simulations with continuously automated industrial applications. KW - Ontology KW - Materials science and engineering KW - Knowledge representation KW - Reproducibility KW - Semantic interoperability KW - Semantic data integration PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-592948 DO - https://doi.org/10.1016/j.matdes.2023.112603 SN - 0264-1275 VL - 237 SP - 1 EP - 12 PB - Elsevier CY - Amsterdam AN - OPUS4-59294 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Klimek, André A1 - Stelzner, Ludwig A1 - Hothan, Sascha A1 - Zehfuß, Jochen T1 - Influence of thermal strain on concrete spalling N2 - Understanding the susceptibility to spalling of concrete members in case of fire is important to evaluate the residual load-bearing capacity. The investigations of the spalling phenomenon of a concrete mixture using real scale members are necessary but expensive to carry out. Reducing the specimen size leads to an increase of boundary effects that can result in a reduced spalling or absence of spalling. In this study, fire tests were carried out on unrestrained, single-sided exposed, cuboid shaped specimens (0.6 m x 0.6 m x 0.29 m) as well as unrestrained and steel ring restrained cylindrical specimens (Ø = 0.47 m, h = 0.29 m), which induce different boundary conditions. These fire tests were carried out on two ordinary concrete mixtures. The two mixtures differ only in the type of aggregates (quartz gravel and basalt grit) and were used to investigate the influence of the thermal expansion of the aggregate on the spalling behaviour of the concrete. The results show a significant increase of the spalling depth due to the restrained thermal expansion achieved by the applied steel rings. Additionally, the type of aggregate has a direct influence on the spalling behaviour of a concrete mixture. The reduction of the boundary effects by the steel rings recreate the test conditions in the centre of a large concrete member. Thus, this type of specimen is suitable to determine the susceptibility to spalling of a material (screening-tests) as preliminary investigations to full scale fire tests. KW - Spalling KW - Concrete KW - Fire test KW - Restraint KW - Screening test PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593350 DO - https://doi.org/10.1617/s11527-023-02274-x VL - 57 SP - 1 EP - 14 PB - Springer AN - OPUS4-59335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinekamp, Christian A1 - Kneiske, Sönke A1 - Guilherme Buzanich, Ana A1 - Ahrens, Mike A1 - Braun, Thomas A1 - Emmerling, Franziska T1 - A fluorolytic sol-gel route to access an amorphous Zr fluoride catalyst: A useful tool for C-F bond activation N2 - A route to a ZrF4 catalyst active in room temperature Friedel–Crafts and dehydrofluorination reactions was developed via a fluorolytic sol–gel route, which was followed by a postfluorination step using a stream of CHClF2. The behaviour of different Zr(IV) precursors in a sol–gel reaction with anhydrous isopropanol/HF solution was investigated. The subsequent post-fluorination step was optimised in its temperature ramp and confirmed the necessity of a fluorination of the generated xerogels to obtain catalytic activity. The process is discussed in the context of the analysis of the materials using Brunauer–Emmett–Teller analysis (BET), powder X-ray diffraction (XRD), infrared spectroscopy (IR), thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). The local structure of the amorphous catalyst was elucidated by extended X-ray absorption fine structure spectroscopy (EXAFS). KW - Catalysis KW - Heterogeneous catalysis KW - C-F bond activation KW - Postfluorination PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593433 DO - https://doi.org/10.1039/D3CY01439H SN - 2044-4761 SP - 1 EP - 8 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59343 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wandtke, Karsten ED - Becker, Amadeus ED - Schröpfer, Dirk ED - Kromm, Arne ED - Kannengießer, Thomas ED - Scharf-Wildenhain, R. ED - Hälsig, A. ED - Hensel, J. T1 - Residual Stress Evolution during Slot Milling for Repair Welding and Wire Arc Additive Manufacturing of High-Strength Steel Components N2 - High-strength steels offer potential for weight optimization due to reduced wall thicknesses in modern constructions. Additive manufacturing processes such as Wire Arc Additive Manufacturing (WAAM) enable the resource-efficient production of structures. In the case of defects occurring in weld seams orWAAM components due to unstable process conditions, the economical solution is local gouging or machining and repair welding. It is important to understand the effects of machining steps on the multiaxial stress state in conjunction with the design-related shrinkage restraints. Research into how welding and slot milling of welds andWAAM structures affects residual stresses is still lacking. For this reason, component-related investigations with high-strength steels with yield strengths ≥790 MPa are carried out in our research. In-situ digital image correlation (DIC) and ex-situ X-ray diffraction (XRD) were used to analyze the stresses and strains induced on specimens during and after milling. The systematic analyses revealed a significant interaction of the stiffness and microstructure of the specimens with the initial residual stresses induced by welding. Subsequent repair welds can result in significantly higher residual stresses. KW - High strength steels KW - Additive manufacturing KW - Residual stress KW - Repair welding KW - Ditigtal image correlation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593515 DO - https://doi.org/10.3390/met14010082 VL - 14 IS - 1 SP - 1 EP - 11 PB - MDPI CY - Basel AN - OPUS4-59351 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andreoli, A. F. A1 - Fantin, Andrea A1 - Kasatikov, S. A1 - Bacurau, V. P. A1 - Widom, M. A1 - Gargarella, P. A1 - Mazzer, E. M. A1 - Woodcock, T. G. A1 - Nielsch, K. A1 - Coury, F. G. T1 - The impact of chemical short-range order on the thermophysical properties of medium- and high-entropy alloys N2 - The unusual behavior observed in the coefficient of thermal expansion and specific heat capacity of CrFeNi, CoCrNi, and CoCrFeNi medium/high-entropy alloys is commonly referred to as the K-state effect. It is shown to be independent of the Curie temperature, as demonstrated by temperature-dependent magnetic moment measurements. CoCrFeNi alloy is chosen for detailed characterization; potential reasons for the K-state effect such as texture, recrystallization, and second-phase precipitation are ruled out. An examination of the electronic structure indicates the formation of a pseudo-gap in the Density of States, which suggests a specific chemical interaction between Ni and Cr atoms upon alloying. Hybrid Monte Carlo/Molecular Dynamic (MC/MD) simulations indicate the presence of non-negligible chemical short-range order (CSRO). Local lattice distortions are shown to be negligible, although deviations around Cr and Ni elements from those expected in a fully disordered structure are experimentally observed by X-ray absorption spectroscopy. The determined bonding distances are in good agreement with MC/MD calculations. A mechanism is proposed to explain the anomalies and calorimetric experiments and their results are used to validate the mechanism. KW - Mechanical Engineering KW - Mechanics of Materials KW - General Materials Science PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595869 DO - https://doi.org/10.1016/j.matdes.2024.112724 SN - 0264-1275 VL - 238 SP - 1 EP - 15 PB - Elsevier B.V. AN - OPUS4-59586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Was, G.S. A1 - Bahn, C.-B. A1 - Busby, J. A1 - Cui, B. A1 - Farkas, D. A1 - Gussev, M. A1 - Rigen He, M. A1 - Hesterberg, J. A1 - Jiao, Z. A1 - Johnson, D. A1 - Kuang, W. A1 - McMurtrey, M. A1 - Robertson, I. A1 - Sinjlawi, A. A1 - Song, M. A1 - Stephenson, K. A1 - Sun, K. A1 - Swaminathan, Srinivasan A1 - Wang, M. A1 - West, E. T1 - How irradiation promotes intergranular stress corrosion crack initiation N2 - Irradiation assisted stress corrosion cracking (IASCC) is a form of intergranular stress corrosion cracking that occurs in irradiated austenitic alloys. It requires an irradiated microstructure along with high temperature water and stress. The process is ubiquitous in that it occurs in a wide range of austenitic alloys and water chemistries, but only when the alloy is irradiated. Despite evidence of this degradation mode that dates back to the 1960s, the mechanism by which it occurs has remained elusive. Here, using high resolution electron backscattering detection to analyze local stress-strain states, high resolution transmission electron microscopy to identify grain boundary phases at crack tips, and decoupling the roles of stress and grain boundary oxidation, we are able to unfold the complexities of the phenomenon to reveal the mechanism by which IASCC occurs. The significance of the findings impacts the mechanical integrity of core components of both current and advanced nuclear reactor designs worldwide. KW - Irradiation KW - Stress corrosion cracking KW - Grain boundaries KW - Oxidation KW - Austenitic alloys PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-595748 DO - https://doi.org/10.1016/j.pmatsci.2024.101255 SN - 0079-6425 VL - 143 SP - 1 EP - 15 PB - Elsevier AN - OPUS4-59574 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mohring, W. A1 - Karafiludis, Stephanos A1 - Manzoni, Anna M. A1 - Laplanche, G. A1 - Schneider, M. A1 - Stephan-Scherb, C. T1 - High-Temperature Corrosion of High- and Medium-Entropy Alloys CrMnFeCoNi and CrCoNi Exposed to a Multi-Oxidant Atmosphere H2O–O2–SO2 N2 - AbstractThe high-temperature corrosion behaviors of the equimolar CrCoNi medium-entropy alloy and CrMnFeCoNi high-entropy alloy were studied in a gas atmosphere consisting of a volumetric mixture of 10% H2O, 2% O2, 0.5% SO2, and 87.5% Ar at 800 °C for up to 96 h. Both alloys were initially single-phase fcc with a mean grain size of ~ 50 μm and a homogeneous chemical composition. The oxide layer thickness of CrMnFeCoNi increased linearly with exposure time while it remained constant at ~ 1 μm for CrCoNi. A Cr2O3 layer and minor amounts of (Co,Ni)Cr2O4 developed on the latter while three oxide layers were detected on the former, i.e., a thin and continuous chromium rich oxide layer at the oxide/alloy interface, a dense (Mn,Cr)3O4 layer in the center and a thick and porous layer of Mn3O4 and MnSO4 at the gas/oxide interface. Additionally, a few metal sulfides were observed in the CrMnFeCoNi matrix. These results were found to be in reasonable agreement with thermodynamic calculations. KW - high entropy alloys KW - corrosion KW - oxidation KW - scanning electron microscopy KW - sulfidation KW - CrMnFeCoNi PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-594189 DO - https://doi.org/10.1007/s44210-023-00026-8 SP - 1 EP - 17 PB - Springer Science and Business Media LLC AN - OPUS4-59418 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, Yijuan A1 - Gawlitza, Kornelia A1 - Valderrey, Virginia A1 - Bell, Jérémy A1 - Rurack, Knut T1 - Polymerizable BODIPY probe crosslinker for the molecularly imprinted polymer-based detection of organic carboxylates via fluorescence N2 - This contribution reports the development of a polymerizable BODIPY-type fluorescent probe targeting small-molecule carboxylates for incorporation into molecularly imprinted polymers (MIPs). The design of the probe crosslinker includes a urea recognition site p-conjugated to the 3-position of the BODIPY core and two methacrylate moieties. Titration experiments with a carboxylate-expressing antibiotic, levofloxacin (LEVO), showed a blue shift of the absorption band as well as a broadening and decrease in emission, attributed to hydrogen bonding between the probe’s urea group and the carboxylate group of the antibiotic. Using this probe crosslinker, core–shell particles with a silica core and a thin MIP shell were prepared for the detection of LEVO. The MIP exhibited highly selective recognition of LEVO, with an imprinting factor of 18.1 compared to the non-imprinted polymer. Transmission electron microscopy confirmed the core–shell structure and spectroscopic studies revealed that the receptor’s positioning leads to a unique perturbation of the polymethinic character of the BODIPY chromophore, entailing the favourable responses. These features are fully preserved in the MIP, whereas no such response was observed for competitors such as ampicillin. The sensory particles allowed to detect LEVO down to submicromolar concentrations in dioxane. We have developed here for the first time a BODIPY probe for organic carboxylates and incorporated it into polymers using the imprinting technique, paving the way for BODIPY-type fluorescent MIP sensors. KW - Fluorescence KW - BODIPY probe KW - Molecularly Imprinted Polymers KW - Sensor Materials KW - Dyes KW - Water analysis KW - Advanced materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598629 DO - https://doi.org/10.1039/D3MA00476G SP - 1 EP - 11 PB - Royal Society of Chemistry (RSC) AN - OPUS4-59862 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Slotyuk, Lyubov A1 - Part, Florian A1 - Schlegel, Moritz-Caspar A1 - Akkerman, Floris T1 - Life Cycle Assessment of the Domestic Micro Heat and Power Generation Proton Exchange Membrane Fuel Cell in Comparison with the Gas Condensing Boiler Plus Electricity from the Grid N2 - The energy demand of private households contributes globally to 36.5% of the total CO2 emissions. To analyze the emissions reduction potential, we conducted a comparative life cycle assessment of a proton exchange membrane fuel cell in a residential application and a conventional system with a stand-alone gas condensing boiler and electricity from a grid mix. The period under review was referred to as the service life of the PEMFC and is assumed to be 10 years (83,038 h of PEMFC). The applicability of this in a single-family house built between 1991 and 2000 under German climatic conditions was investigated. The functional unit is set to the thermal energy demand of 16,244 kWh/a and electricity demand of 4919 kWh/a of a single-family house. The impact assessment method “CML 2001–August 2016” was used in this investigation. The manufacturing phase of the proton exchange membrane fuel cell showed disadvantages, whereby the use phase had significant advantages in most of the environmental impact categories as compared to the conventional energy supply system. Considering the whole life cycle, the advantages from the use phase could outperform the disadvantages from the manufacturing phase in most of the impact categories, except for ADP elements and TETP. KW - Sustainability KW - Circular Economy KW - Comparative life cycle assessment KW - Proton exchange membrane fuel cell KW - Gas condensing boiler KW - Micro heat and power generation KW - Residential application KW - Single-family house energy supply system PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598134 DO - https://doi.org/10.3390/su16062348 VL - 16 IS - 6 SP - 1 EP - 16 PB - MDPI AG AN - OPUS4-59813 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wetzel, Annica A1 - Morell, Daniel A1 - von der Au, Marcus A1 - Wittstock, Gunther A1 - Ozcan, Ozlem A1 - Witt, Julia T1 - Transpassive Metal Dissolution vs. Oxygen Evolution Reaction: Implication for Alloy Stability and Electrocatalysis T1 - Transpassive Metallauflösung vs. Sauerstoffentwicklung: Auswirkungen auf Legierungsstabilität und Elektrokatalyse N2 - Multi-principal element alloys (MPEAs) are gaining interest in corrosion and electrocatalysis research due to their electrochemical stability across a broad pH range and the design flexibility they offer. Using the equimolar CrCoNi alloy, we observe significant metal dissolution in a corrosive electrolyte (0.1 M NaCl, pH 2) concurrently with the oxygen evolution reaction (OER) in the transpassive region despite the absence of hysteresis in polarization curves or other obvious corrosion indicators. We present a characterization scheme to delineate the contribution of OER and alloy dissolution, using scanning electrochemical microscopy (SECM) for OER-onset detection, and quantitative chemical analysis with inductively coupled-mass spectrometry (ICP-MS) and ultraviolet visible light (UV-Vis) spectroscopy to elucidate metal dissolution processes. In-situ electrochemical atomic force microscopy (EC-AFM) revealed that the transpassive metal dissolution on CrCoNi is dominated by intergranular corrosion. These results have significant implications for the stability of MPEAs in corrosion systems, emphasizing the necessity of analytically determining metal ions released from MPEA electrodes into the electrolyte when evaluating Faradaic efficiencies of OER catalysts. The release of transition metal ions not only reduces the Faradaic efficiency of electrolyzers but may also cause poisoning and degradation of membranes in electrochemical reactors. N2 - Multi-Hauptelement-Legierungen (MPEAs) gewinnen in der Korrosions- und Elektrokatalyseforschung aufgrund ihrer elektrochemischen Stabilität über einen breiten pH-Bereich und der Vielfalt der möglichen chemischen Zusammensetzungen zunehmend an Interesse. In unseren Untersuchungen mit der äquimolaren CrCoNi-Legierung in einem sauren Elektrolyten (0.1 M NaCl, pH 2) beobachteten wir eine signifikante Metallauflösung, die mit der Sauerstoffentwicklungsreaktion (OER) im transpassiven Bereich einhergeht, obwohl in zyklischen Polarisationskurven keine Hysterese auftrat oder andere offensichtliche Korrosionsindikatoren vorlagen. In diesem Artikel wird ein Charakterisierungskonzept eingeführt, dass die Beiträge der OER und der Legierungsauflösung differenziert. Hierfür kommt die elektrochemische Rastermikroskopie (SECM) zum Nachweis des Beginns der OER und die quantitative chemische Analyse mit induktiv gekoppelter Massenspektrometrie (ICP-MS) und UV/Vis-Spektrometrie zur Aufklärung der Metallauflösungsprozesse zum Einsatz. Die elektrochemische In situ-Atomkraftmikroskopie (EC-AFM) zeigte, dass die intergranulare Korrosion der dominierende Mechanismus der transpassive Metallauflösung von CrCoNi ist. Diese Ergebnisse besitzen erhebliche Auswirkungen für die Beurteilung der Stabilität von MPEAs in Korrosionssystemen und der Stromausbeute von OER-Katalysatoren auf der Basis von MPEAs. Die Daten unterstreichen die Notwendigkeit der analytischen Bestimmung von Metallionen, die von MPEA-Elektroden freigesetzt werden. Die Freisetzung von Übergangsmetallionen verringert nicht nur die Stromausbeute von Elektrolyseuren, sondern kann zu einer Schädigung von Membranen in elektrochemischen Reaktoren führen. KW - Transpassive dissolution KW - Corrosion KW - Multi-prinicpal element alloys (MPEAs) KW - Passivation PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-597045 DO - https://doi.org/10.1002/anie.202317058 SP - 1 EP - 8 PB - Wiley VHC-Verlag AN - OPUS4-59704 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoogendoorn, Levi A1 - Huertas, Mauricio A1 - Nitz, Phillip A1 - Qi, Naiyu A1 - Baller, Johannes A1 - Prinz, Carsten A1 - Graeber, Gustav T1 - Sustainable, Low‐Cost Sorbents Based on Calcium Chloride‐Loaded Polyacrylamide Hydrogels N2 - AbstractSorbents are promising materials for applications in atmospheric water harvesting, thermal energy storage, and passive cooling, thereby addressing central challenges related to water scarcity and the global energy transition. Recently, hygroscopic hydrogel composites have emerged as high‐performance sorbents. However, many of these systems are fabricated with unsustainable and costly sorbent materials, which hinders their wide deployment. Here, the synthesis of high‐performance, cost‐efficient polyacrylamide hydrogels loaded with unprecedented amounts of calcium chloride is demonstrated. To this end, the swelling procedure of polyacrylamide hydrogels in aqueous calcium chloride solutions is optimized. The achievable salt loading in the hydrogel is characterized as a function of temperature, calcium chloride concentration in the swelling solution, and the hydrogel preparation conditions. The obtained hydrogel‐salt composites are shown to be stable under repeated sorption‐desorption cycling and enable water uptakes of 0.92 and 2.38 grams of water per gram of dry materials at 30% and 70% relative humidity, respectively. The resulting cost‐performance ratio substantially exceeds lithium chloride‐based systems. Further, the mechanistic insights on hydrogel salt interactions can guide the design of sustainable and low‐cost sorbent materials for future applications in water and energy. KW - Electrochemistry KW - Condensed Matter Physics KW - Biomaterials KW - Electronic, Optical and Magnetic Materials PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598366 DO - https://doi.org/10.1002/adfm.202314680 SN - 1616-301X SP - 1 EP - 10 PB - Wiley VHC-Verlag AN - OPUS4-59836 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seifert, Lando A1 - Grunewald, Andreas A1 - Müller, Thoralf A1 - Ebell, Gino T1 - Stress corrosion tests for prestressing steels—Part 1: The influence of surface condition and test solution composition on hydrogen charging N2 - Tests for assessing prestressing steels' susceptibility to hydrogen‐induced stress corrosion cracking are essential for approvals, in‐house monitoring, and third‐party material testing. According to ISO 15630‐3, the time to brittle fracture by constant load under corrosive conditions in thiocyanate test solutions (A or B) at 50°C is measured. In the literature, a high scattering in stress corrosion tests is reported, which questions the integrity of the test procedure. This paper shows the results of studies about the influence of solution composition on hydrogen charging in electrochemical and permeation measurements. Electrochemical experiments show that polished steel surfaces without common drawing layers have more consistent free corrosion currents, polarization resistances, and B‐values in solution A with low scattering compared to the solution B experiments. The influence of temperature at 50°C and an ambient temperature of 22°C was also tested. KW - Drawing layers KW - Hydrogen‐induced stress corrosion cracking KW - Permeation measurements KW - Prestressing steels KW - Stress corrosion tests KW - Surface conditions KW - Test solutions PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598738 DO - https://doi.org/10.1002/maco.202313948 SP - 1 EP - 13 PB - Wiley‐VCH GmbH AN - OPUS4-59873 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Böttcher, Nils A1 - Dayani, Shahabeddin A1 - Markötter, Henning A1 - Bau, Alexander A1 - Setzchen, Max A1 - Schmidt, Anita A1 - Kowal, Julia A1 - Krug von Nidda, Jonas T1 - High Precision Nail‐Penetration Setup for the Controlled Thermal Runaway Initiation of Lithium‐Ion Cells at Very Low Temperatures N2 - A high precision nail‐penetration (NP) tool for characterizing the mechanically induced thermal‐runaway (TR) of lithium‐ion battery (LIB) cells in a defined range of temperatures down to −140 °C was developed. To understand the cell specific behavior at low temperatures aiming at the determination of safe handling conditions, different scenarios are analyzed. First, accuracy tests of the NP‐tool regarding motion and penetration depth are conducted with cylindrical cells at different temperatures. Thus, postmortem computer tomographic (CT) images are compared to the data measured with the newly integrated 3‐axis force sensor which is further combined with a high‐resolution position sensor. The herein developed setup allows evaluation of the NP‐metrics at an accuracy of ±1 pierced electrode layer without CT‐scans. Further NP examinations at 20 °C of fully charged cylindrical lithium nickel manganese cobalt oxide cells reveal a reproducible minimum damage as a reliable TR‐trigger. Moreover, NP‐tests at low temperature disclose a relation of the short circuit conductivity and TR‐reactions during subsequent rethermalization to room temperature. Finally, the implementation of a novel fixture for a controlled very fast cooling of LIB‐cells during critical damage opens the way to investigate the individual steps during a TR and, thus, to gain important information of the specific TR‐mechanism of different LIB‐cells. KW - Battery Safety KW - High-precision nail penetration KW - Lithium-ion batteries KW - Abuse testing KW - Thermal runaway PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598127 DO - https://doi.org/10.1002/ente.202301379 SN - 2194-4288 SP - 1 EP - 13 PB - Wiley VHC-Verlag AN - OPUS4-59812 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Groschke, Matthias A1 - Becker, Roland T1 - Comparison of carrier gases for the separation and quantification of mineral oil hydrocarbon (MOH) fractions using online coupled high performance liquid chromatography-gas chromatography-flame ionisation detection N2 - On-line coupled high performance liquid chromatography-gas chromatography-flame ionisation detection (HPLC-GC-FID) was used to compare the effect of hydrogen, helium and nitrogen as carrier gases on the chromatographic characteristics for the quantification of mineral oil hydrocarbon (MOH) traces in food related matrices. After optimisation of chromatographic parameters nitrogen carrier gas exhibited characteristics equivalent to hydrogen and helium regarding requirements set by current guidelines and standardisation such as linear range, quantification limit and carry over. Though nitrogen expectedly led to greater peak widths, all required separations of standard compounds were sufficient and humps of saturated mineral oil hydrocarbons (MOSH) and aromatic mineral oil hydrocarbons (MOAH) were appropriate to enable quantitation similar to situations where hydrogen or helium had been used. Slightly increased peak widths of individual hump components did not affect shapes and widths of the MOSH and MOAH humps were not significantly affected by the use of nitrogen as carrier gas. Notably, nitrogen carrier gas led to less solvent peak tailing and smaller baseline offset. Overall, nitrogen may be regarded as viable alternative to hydrogen or helium and may even extend the range of quantifiable compounds to highly volatile hydrocarbon eluting directly after the solvent peak. KW - Mineral oil hydrocarobons KW - Food KW - Liquid chromatography KW - Gas chromatography KW - MOSH/MOAH PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601450 DO - https://doi.org/10.1016/j.chroma.2024.464946 SN - 0021-9673 VL - 1726 SP - 1 EP - 7 PB - Elsevier CY - New York, NY AN - OPUS4-60145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - López-Iglesias, C. A1 - Markovina, A. A1 - Nirmalananthan-Budau, N. A1 - Resch-Genger, Ute A1 - Klinger, D. T1 - Optically monitoring the microenvironment of a hydrophobic cargo in amphiphilic nanogels: influence of network composition on loading and release N2 - Amphiphilic nanogels (ANGs) are promising carriers for hydrophobic cargos such as drugs, dyes, and catalysts. Loading content and release kinetics of these compounds are controlled by type and number of hydrophobic groups in the amphiphilic copolymer network. Thus, understanding the interactions between cargo and colloidal carrier is mandatory for a tailor-made and cargo-specific ANG design. To systematically explore the influence of the network composition on these interactions, we prepared a set of ANGs of different amphiphilicity and loaded these ANGs with varying concentrations of the solvatochromic dye Nile Red (NR). Here, NR acts as a hydrophobic model cargo to optically probe the polarity of its microenvironment. Analysis of the NR emission spectra as well as measurements of the fluorescence quantum yields and decay kinetics revealed a decrease in the polarity of the NR microenvironment with increasing hydrophobicity of the hydrophobic groups in the ANG network and dye–dye interactions at higher loading concentrations. At low NR concentrations, the hydrophobic cargo NR is encapsulated in the hydrophobic domains. Increasing NR concentrations resulted in probe molecules located in a more hydrophilic environment, i.e., at the nanodomain border, and favored dye–dye interactions and NR aggregation. These results correlate well with release experiments, indicating first NR release from more hydrophilic network locations. Overall, our findings demonstrate the importance to understand carrier–drug interactions for efficient loading and controlled release profiles in amphiphilic nanogels. KW - Particle KW - Energy transfer KW - Limit of detection KW - Polymer KW - Luminescence KW - Quantitative spectroscopy KW - Nano KW - Quantum yield KW - Lifetime KW - Quality assurance KW - Dye KW - Probe KW - Sensor KW - Nile Red PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601603 DO - https://doi.org/10.1039/d4nr00051j SN - 2040-3364 IS - 16 SP - 9525 EP - 9535 PB - The Royal Society of Chemistry AN - OPUS4-60160 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Epping, Ruben A1 - Lisec, Jan A1 - Koch, Matthias T1 - Changes in Black Truffle (Tuber melanosporum) Aroma during Storage under Different Conditions N2 - The enticing aroma of truffles is a key factor for their culinary value. Although all truffle species tend to be pricy, the most intensely aromatic species are the most sought after. Research into the aroma of truffles encompasses various disciplines including chemistry, biology, and sensory science. This study focusses on the chemical composition of the aroma of black truffles (Tuber melanosporum) and the changes occurring under different storage conditions. For this, truffle samples were stored under different treatments, at different temperatures, and measured over a total storage time of 12 days. Measurements of the truffle aroma profiles were taken with SPME/GC–MS at regular intervals. To handle the ample data collected, a systematic approach utilizing multivariate data analysis techniques was taken. This approach led to a vast amount of data which we made publicly available for future exploration. Results reveal the complexity of aroma changes, with 695 compounds identified, highlighting the need for a comprehensive understanding. Principal component analyses offer initial insights into truffle composition, while individual compounds may serve as markers for age (formic acid, 1-methylpropyl ester), freshness (2-Methyl-1-propanal; 1-(methylthio)-propane), freezing (tetrahydrofuran), salt treatment (1-chloropentane), or heat exposure (4-hydroxy-3-methyl-2-butanone). This research suggests that heat treatment or salt contact significantly affects truffle aroma, while freezing and cutting have less pronounced effects in comparison. The enrichment of compounds showing significant changes during storage was investigated with a metabolomic pathway analysis. The involvement of some of the enriched compounds on the pyruvate/glycolysis and sulfur pathways was shown. KW - Mass Spectrometry KW - Metabolomics KW - Tuber melanosporum KW - Truffle Aroma PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601731 DO - https://doi.org/10.3390/jof10050354 VL - 10 IS - 5 SP - 1 EP - 22 PB - MDPI AN - OPUS4-60173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bauer, L.J. A1 - Wieder, Frank A1 - Truong, V. A1 - Förste, F. A1 - Wagener, Y. A1 - Jonas, A. A1 - Praetz, S: A1 - Schlesiger, C. A1 - Kupsch, Andreas A1 - Müller, B.R. A1 - Kanngießer, B. A1 - Zaslansky, P. A1 - Mantouvalou, I. T1 - Absorption Correction for 3D Elemental Distributions of Dental Composite Materials Using Laboratory Confocal Micro-X-ray Fluorescence Spectroscopy N2 - Confocal micro-X-ray fluorescence (micro-XRF) spectroscopy facilitates three-dimensional (3D) elemental imaging of heterogeneous samples in the micrometer range. Laboratory setups using X-ray tube excitation render the method accessible for diverse research fields but interpretation of results and quantification remain challenging. The attenuation of X-rays in composites depends on the photon energy as well as on the composition and density of the material. For confocal micro-XRF, attenuation severely impacts elemental distribution information, as the signal from deeper layers is distorted by superficial layers. Absorption correction and quantification of fluorescence measurements in heterogeneous composite samples have so far not been reported. Here, an absorption correction approach for confocal micro-XRF combining density information from microcomputed tomography (micro-CT) data with laboratory X-ray absorption spectroscopy (XAS) and synchrotron transmission measurements is presented. The energy dependency of the probing volume is considered during the correction. The methodology is demonstrated on a model composite sample consisting of a bovine tooth with a clinically used restoration material. KW - Micro X-ray fluorescence spectroscopy KW - Dental composite materials KW - Computed tomography KW - Absorption correction PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601630 DO - https://doi.org/10.1021/acs.analchem.4c00116 SN - 0003-2700 SN - 1520-6882 VL - 96 IS - 21 SP - 8441 EP - 8449 PB - American Chemical Society Publications CY - Washington, DC AN - OPUS4-60163 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilling, Markus A1 - Niebergall, Ute A1 - Marschall, Niklas A1 - Meinel, Dietmar A1 - Böhning, Martin T1 - Relation of craze to crack length during slow crack growth phenomena in high‐density polyethylene N2 - The craze‐crack mechanism occurring in high‐density polyethylene (HDPE) causing slow crack growth and environmental stress cracking is investigated in detail with respect to the relation of crack length and the related craze zone. This is essential for the understanding of the resulting features of the formed fracture surface and their interpretation in the context of the transition from crack propagation to ductile shear deformation. It turns out that an already formed craze zone does not inevitably result in formation of a propagating crack, but could also undergo ductile failure. For the examination, the full notch creep test (FNCT) was employed with a subsequent advanced fracture surface analysis that was performed using various imaging techniques: light microscopy, laser scanning microscopy, scanning electron microscopy, and X‐ray micro computed tomography scan. FNCT specimens were progressively damaged for increasing durations under standard test conditions applying Arkopal, the standard surfactant solution, and biodiesel as test media were used to analyze the stepwise growth of cracks and crazes. From considerations based on well‐established fracture mechanics approaches, a theoretical correlation between the length of the actual crack and the length of the preceding craze zone was established that could be evidenced and affirmed by FNCT fracture surface analysis. Moreover, the yield strength of a HDPE material exposed to a certain medium as detected by a classic tensile test was found to be the crucial value of true stress to induce the transition from crack propagation due to the craze‐crack mechanism to shear deformation during FNCT measurements. Highlights - Progress of crack formation in high‐density polyethylene is analyzed by different imaging techniques - Determined growth rates depend on distinction between craze zone and crack - The ratio of the present crack to the anteceding craze zone is validated theoretically - The transition from crack propagation to ductile shear deformation is identified - An already formed craze zone may still fail by ductile mechanisms KW - Craze-crack mechanism KW - Environmental stress cracking (ESC) KW - Full notch creep test (FNCT) KW - Laser scanning microscopy (LSM) KW - Slow crack growth (SCG) KW - X-ray computed tomography (CT) PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601831 DO - https://doi.org/10.1002/pen.26698 SN - 1548-2634 VL - 64 IS - 6 SP - 2387 EP - 2403 PB - Wiley AN - OPUS4-60183 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nawaz, Q. A1 - Blaeß, Carsten A1 - Mueller, Ralf A1 - Boccaccini, A.R. T1 - Processing and cytocompatibility of Cu-doped and undoped fluoride-containing bioactive glasses N2 - Sintered or additive-manufactured bioactive glass (BG) scaffolds are highly interesting for bone replacement applications. However, crystallization often limits the high-temperature processability of bioactive glasses (BGs). Thus, the BG composition must combine high bioactivity and processability. In this study, three BGs with nominal molar (%) compositions 54.6SiO2-1.7P2O3-22.1CaO-6.0Na2O-7.9K2O-7.7MgO (13–93), 44.8SiO2-2.5P2O3-36.5CaO-6.6Na2O-6.6K2O-3.0CaF2 (F3) and 44.8SiO2-2.5P2O3-35.5CaO-6.6Na2O-6.6K2O-3.0CaF2-1.0CuO (F3–Cu) were investigated. The dissolution and ion release kinetics were investigated on milled glass powder and crystallized particles (500–600 μm). All glasses showed the precipitation of hydroxyapatite (HAp) crystals after 7 days of immersion in simulated body fluid. No significant differences in ion release from glass and crystalline samples were detected. The influence of surface roughness on cytocompatibility and growth of preosteoblast cells (MC3T3-E1) was investigated on sintered and polished BG pellets. Results showed that sintered BG pellets were cytocompatible, and cells were seen to be well attached and spread on the surface after 5 days of incubation. The results showed an inverse relation of cell viability with the surface roughness of pellets, and cells were seen to attach and spread along the direction of scratches. KW - Bioactive glass KW - Crystallization KW - Solubility KW - Cytocompatibility KW - Surface roughness PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-598257 DO - https://doi.org/10.1016/j.oceram.2024.100586 SN - 2666-5395 VL - 18 SP - 1 EP - 8 PB - Elsevier Ltd. AN - OPUS4-59825 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becker, Tina A1 - Stark, T. A1 - Arduini, M. A1 - Manara, J. A1 - Altenburg, Simon T1 - Knowing the spectral directional emissivity of 316L and AlSi10Mg PBF-LB/M surfaces: Gamechanger for quantitative in situ monitoring N2 - For a deep process understanding of the laser powder bed fusion process (PBF-LB/M), recording of the occurring surface temperatures is of utmost interest and would help to pave the way for reliable process monitoring and quality assurance. A notable number of approaches for in-process monitoring of the PBF-LB/M process focus on the monitoring of thermal process signatures. However, due to the elaborate calibration effort and the lack of knowledge about the occurring spectral directional emissivity, only a few approaches attempt to measure real temperatures. In this study, to gain initial insights into occurring in the PBF-LB/M process, measurements on PBF-LB/M specimens and metal powder specimens were performed for higher temperatures up to T = 1290 °C by means of the emissivity measurement apparatus (EMMA) of the Center for Applied Energy Research (CAE, Wuerzburg, Germany). Also, measurements at ambient temperatures were performed with a suitable measurement setup. Two different materials—stainless steel 316L and aluminum AlSi10Mg—were examined. The investigated wavelength λ ranges from the visible range (λ-VIS= 0.40–0.75 µm) up to the infrared, λ = 20 µm. The influence of the following factors were investigated: azimuth angle φ, specimen temperature TS, surface texture as for PBF-LB/M surfaces with different scan angles α, and powder surfaces with different layer thicknesses t. T2 - Rapid.Tech 3D 2024 CY - Erfurt, Germany DA - 14.05.2024 KW - PBF-LB/M KW - In situ monitoring KW - Emissivity KW - Additive manufacturing PY - 2024 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-601471 DO - https://doi.org/10.1007/s40964-024-00665-2 SN - 2363-9520 SP - 1 EP - 10 PB - Springer CY - Cham, Switzerland AN - OPUS4-60147 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -