TY - JOUR A1 - Cabeza, Sandra A1 - Cawley, P. A1 - Li, Z. A1 - Dixon, S. A1 - Jarvis, R. A1 - Nagy, P. B. T1 - Experimental studies of the magneto-mechanical memory (MMM) technique using permanently installed magnetic sensor arrays N2 - The magneto-mechanical memory (MMM) method, that is often referred to as the metal magnetic memory method, has been reported to be a non-destructive testing technique capable of quantifying stress concentrations and detecting defects in ferromagnetic materials. The underlying mechanism behind MMM has been explained in the literature, but the sensitivity to stress concentration has not been satisfactorily investigated. In this paper, both the normal and tangential components of the stress-induced MMM signal were measured by permanently installed magnetic sensor arrays on specimens made from three grades of L80 alloy steel and 20 other structural steels; tests were also carried out on a pipe made from the 4140-L80 steel. As expected, the stress history affects the MMM signal, but the experimental results show that significant irreversible change of magnetization always occurs only in the first cycle of loading regardless whether the deformation is purely elastic or partially plastic. If the peak stress level is increased at a given point during cycling, the immediately following next cycle acts as a new “first” cycle at that peak stress level and causes additional significant irreversible change of magnetization, but there is no evidence that plastic deformation might build up a cumulative magnetization. The MMM effect is very small in the steel samples tested, indicating that it will not be useful in field applications. In un-notched specimens the irreversible change in magnetization caused a proportional change in the measured external magnetic field on the order of only 5–10 A/m, while in the case of notched specimens the leakage field was on the order of 30–60 A/m. KW - Magneto-mechanical memory KW - Stress concentration KW - Permanently installed sensors KW - Irreversible change KW - Cumulative magnetization PY - 2017 DO - https://doi.org/10.1016/j.ndteint.2017.07.019 SN - 0963-8695 SN - 1879-1174 VL - 92 SP - 136 EP - 148 PB - Elsevier Ltd. AN - OPUS4-42936 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Ballach, F. A1 - Bartscher, M. A1 - Bellon, Carsten A1 - Borges de Oliveira, F. A1 - Braun, M. A1 - Dennerlein, F. A1 - Flessner, M. A1 - Fuchs, P. A1 - Günnewig, O. A1 - Hausotte, T. A1 - Hess, J. A1 - Kasperl, S. A1 - Kirschbaum, K. A1 - Li, K. A1 - Maass, N. A1 - Mayer, T. A1 - Orth, Anthony A1 - Reuter, T. A1 - Suppes, A. A1 - von Schmid, M. A1 - Weiß, D. T1 - Realistische Simulation realer Röntgencomputertomografie-Systeme mit basisqualifizierter Simulationssoftware – CTSimU2 BT - Abschlussbericht N2 - Das Förderprojekt CTSimU2 baute auf den Ergebnissen des Projektes CTSimU auf. Dieses Vorprojekt erarbeitete ein (Basis-)Qualifizierungsframework für Simulationssoftwares zur Anwendung bei der Röntgen-CT für dimensionelle Messungen. Dabei stand die ausreichende physikalische Korrektheit der Durchstrahlungssimulation im Vordergrund. Für die realitätsnahe Simulation einer CT-Anlage in einer Simulationssoftware (Digitales Modell) ist jedoch nicht nur die Korrektheit der Simulationssoftware selbst, sondern auch die Güte der Parametrisierung des realen CT-Systems in der Simulationssoftware entscheidend – dies stellte den Ausgangspunkt dar. Die Parametrisierung eines CT-Systems in einer Simulationssoftware lässt sich in vier Schritte unterteilen: nach der Datenaufnahme am realen CT-System folgt die Auswertung der aufgenommenen Daten für die Generierung allgemeiner Parameterangaben. Als letztes folgte die Übertragung der Parameter in die spezifischen Simulationssoftwares und die Validierung der resultierenden Simulationsparameter. Die Methodik der Datenaufnahme am CT und die Auswertung der Daten wurde in einem Werkzeugkasten allgemein beschrieben. Der dritte Schritt, die Umsetzung der Parameter, war softwarespezifisch und wurde beispielhaft mit den vorhandenen Simulationssoftwares durchgeführt. Die Validierung der Parameter war standardisierbar und konnte durch den entwickelten Test geleistet werden, auf dessen Basis die ausreichend korrekte Simulation einer realen Anlage beurteilt werden konnte. Endresultat des Projektes war ein Richtlinienentwurf (z. B. VDI/VDE 2630) zu diesem Test, der einen informativen Annex zum Stand der Technik bezüglich der Möglichkeiten zur Parameterbestimmung enthält. Mit einer Simulationssoftware, die die Basisqualifizierung aus CTSimU bestanden hat und einen Parameterdatensatz für ein reales CT-System enthält, der den Test aus CTSimU2 bestanden hat, können realistische Simulationen dieses CT-Systems möglich sein. KW - Computertomografie KW - Simulation KW - Dimensionelles Messen PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-641719 DO - https://doi.org/10.34657/21602 N1 - Dieses Projekt wurde durch die Förderrichtlinie WIPANO gefördert und durch das Bundesministerium für Wirtschaft und Klimaschutz (2022 -2025) finanziert. Der Projektträger Jülich verwaltet die Projekte der Förderrichtlinie WIPANO. SP - 1 EP - 22 PB - TIB Technische Informationsbibliothek CY - Hannover AN - OPUS4-64171 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Raab, A. R. A1 - Grießler, T. R. A1 - Rück, D. A1 - Li, Z. A1 - Zens, A. A1 - Bruckner, J. R. A1 - Huber, P. A1 - Schönhals, Andreas A1 - Szymoniak, Paulina A1 - Laschat, S. T1 - Salt complexation drives liquid crystalline selfassembly in crown ether–amino acid hybrids N2 - Crown ether–amino acid hybrids represent a promising class of amphiphilic molecules combining ion recognition with self-assembly capabilities. Despite extensive studies on their binding properties, the influence of inorganic salt complexation on their liquid crystalline behaviour remains underexplored. Here we synthesized amphiphilic [18]-crown-6 derivatives of L-dihydroxyphenylalanine and tetrahydroisoquinoline analogues, systematically investigating the effects of alkyl chain length and salt type on mesophase formation. Complexation with various salts induced liquid crystalline phases, transitioning from smectic A to columnar hexagonal structures as anion size and alkyl chain length increased. Structural analyses and electron density mapping revealed assembly into charged superdiscs forming columnar stacks with tunable ion channels. Broadband dielectric spectroscopy highlighted differences in molecular mobility and conductivity linked to molecular design. These findings establish salt complexation as a key strategy to control self-assembly and ion transport in crown ether–amino acid hybrids, advancing their potential in responsive soft materials and ion-conductive applications. KW - Ionic liquid crystals PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655986 DO - https://doi.org/10.1039/d5tc04129e SP - 1 EP - 18 PB - Royal Society of Chemistry (RSC) AN - OPUS4-65598 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Paris, O. A1 - Li, C. A1 - Siegel, S. A1 - Weseloh, G. A1 - Emmerling, Franziska A1 - Riesemeier, Heinrich A1 - Erko, A. A1 - Fratzl, P. T1 - A new experimental station for simultaneous X-ray microbeam scanning for small- and wide-angle scattering and fluorescence at BESSY II N2 - A new instrument for simultaneous microbeam small- and wide-angle X-ray scattering and X-ray fluorescence (SAXS/WAXS/XRF) is presented. The instrument is installed at the microfocus beamline at BESSY II and provides a beam of 10 µm size with a flux of about 109 photons s-1. A SAXS resolution up to 500 Å d-spacing and a range of scattering vectors of almost three orders of magnitude are reached by using a large-area high-resolution CCD-based detector for simultaneous SAXS/WAXS. The instrument is particularly suited for scanning SAXS/WAXS/XRF experiments on hierarchically structured biological tissues. The necessary infrastructure, such as a cryo-stream facility and an on-site preparation laboratory for biological specimens, are available. KW - Scanning SAXS KW - Scanning WAXS KW - Microbeam KW - Synchrotron radiation PY - 2007 SN - 0021-8898 SN - 1600-5767 VL - 40 IS - Supplement SP - s466 EP - s470 PB - Blackwell CY - Oxford AN - OPUS4-15049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kim, Y.S. A1 - Li, Y.-C. A1 - Pitts, W.M. A1 - Werrel, Martin A1 - Davis, R.D. T1 - Rapid growing clay coatings to reduce the fire threat of furniture N2 - Layer-by-layer (LbL) assembly coatings reduce the flammability of textiles and polyurethane foam but require extensive repetitive processing steps to produce the desired coating thickness and nanoparticle fire retardant content that translates into a fire retardant coating. Reported here is a new hybrid bi-layer (BL) approach to fabricate fire retardant coatings on polyurethane foam. Utilizing hydrogen bonding and electrostatic attraction along with the pH adjustment, a fast growing coating with significant fire retardant clay content was achieved. This hybrid BL coating exhibits significant fire performance improvement in both bench scale and real scale tests. Cone calorimetry bench scale tests show a 42% and 71% reduction in peak and average heat release rates, respectively. Real scale furniture mockups constructed using the hybrid LbL coating reduced the peak and average heat release rates by 53% and 63%, respectively. This is the first time that the fire safety in a real scale test has been reported for any LbL technology. This hybrid LbL coating is the fastest approach to develop an effective fire retardant coating for polyurethane foam. KW - Layer-by-layer assembly KW - Polyurethane foam KW - Sodium montmorillonite KW - Flame retardant KW - Real scale mockup PY - 2014 DO - https://doi.org/10.1021/am405259n SN - 1944-8244 SN - 0013-936X SN - 1944-8252 VL - 6 IS - 3 SP - 2146 EP - 2152 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-31489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Deng, C. A1 - Yin, Huajie A1 - Li, R.-M. A1 - Huang, S.-C. A1 - Schartel, Bernhard A1 - Wang, Y.-Z. T1 - Modes of action of a mono-component intumescent flame retardant MAPP in polyethylene-octene elastomer N2 - A mono-component intumescent flame retardant named ethylenediamine-modified ammonium polyphosphate (MAPP) is used in polyethylene-octene elastomer (POE). Insight into the flame-retardant mechanisms of the MAPP is provided from a new perspective. The fire performance of POE/MAPP composites is investigated by oxygen index (OI) and vertical burning (UL-94) tests. POE Composite containing 35 wt% MAPP achieves a V-0 rating, and its OI is 29.3 vol%. The thermogravimetric Analysis (TGA) and Fourier transform infrared spectra (FTIR) confirm that the incorporation of ethylenediamine changes the thermal decomposition of APP, mainly resulting in the formation of char layer with a thermally stable structure. Cone calorimeter analysis revealed the flame-retardant modes of action of MAPP in POE under forced-flaming conditions. Quantitative analysis illustrates that both the residue due to charring and the fuel dilution/flame Inhibition resulting from the release of incombustible products/ phosphorus species decrease the total heat release (fire load) by 20e28%. The residue increases linearly with increasing MAPP content, whereas the reduction in effective heat of combustion levels off. Moreover, the flame-retardant effect resulting from the protective properties of the char is discovered to be the dominant mode of action (up to 85% reduction) with respect to the peak heat release rate, leading to the excellent flame retardancy of POE/MAPP. KW - Ammonium polyphosphate KW - Flame retardant KW - Carbonization KW - Elastomer PY - 2017 DO - https://doi.org/10.1016/j.polymdegradstab.2017.03.006 SN - 0141-3910 SN - 1873-2321 VL - 138 SP - 142 EP - 150 PB - Elsevier AN - OPUS4-39901 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Werner A1 - Jakob, Ines A1 - Li, C.S. A1 - Tatzky-Gerth, Renate T1 - Durability of polyolefin geosynthetic drains N2 - The German Federal Institute for Materials Research and Testing (BAM) has established a testing guideline to assess the suitability of geosynthetic or geocomposite drain (GCD) elements for final landfill cover systems. In an earlier paper the uniform procedure according to the BAM guideline for determining long-term water flow capacity was described, and the structural stability of drain cores under creep was investigated. The extrapolation of creep curves is permissible only when it can be shown, over the extrapolated period (at least 100 years), that oxidative aging does not invoke any relevant changes in the polyolefin material. This can be shown by measuring antioxidant depletion and mechanical degradation of the drain cores and filter/protection geotextiles in oven aging and water immersion tests. In this paper the results of such aging studies on three different GCD products are reported. Degradation of the tensile strength of HALS-stabilized polypropylene needle-punched nonwoven geotextiles (PP NWGTs) starts right from the beginning of the oven aging. This has to be taken into account for lifetime predictions based on residual tensile strength. The rate of oxidative degradation of NWGTs decreases significantly with increasing mass per area. Therefore the expected service life sets a limit on acceptable geotextile grammage. Antioxidant depletion in the drain cores, which are made of relatively thick PP strands or HDPE ribs, is about an order of magnitude slower than in filter and protection NWGTs, which are made of thin fibers. Service life values in excess of 100 years may be obtained for the products when the geotextiles and drain cores are properly stabilized and designed. KW - Geosynthetics KW - Geosynthetic drain elements KW - Long-term behavior KW - Oxidative degradation PY - 2009 DO - https://doi.org/10.1680/gein.2009.16.1.28 SN - 1072-6349 VL - 16 IS - 1 SP - 28 EP - 42 PB - Telford CY - London, UK AN - OPUS4-18999 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zimmermann, Yoel A1 - Bazgir, Adib A1 - Al-Feghali, Alexander A1 - Ansari, Mehrad A1 - Bocarsly, Joshua A1 - Brinson, L Catherine A1 - Chiang, Yuan A1 - Circi, Defne A1 - Chiu, Min-Hsueh A1 - Daelman, Nathan A1 - Evans, Matthew A1 - Gangan, Abhijeet S A1 - George, Janine A1 - Harb, Hassan A1 - Khalighinejad, Ghazal A1 - Takrim Khan, Sartaaj A1 - Klawohn, Sascha A1 - Lederbauer, Magdalena A1 - Mahjoubi, Soroush A1 - Mohr, Bernadette A1 - Mohamad Moosavi, Seyed A1 - Naik, Aakash Ashok A1 - Ozhan, Aleyna Beste A1 - Plessers, Dieter A1 - Roy, Aritra A1 - Schoeppach, Fabian A1 - Schwaller, Philippe A1 - Terboven, Carla A1 - Ueltzen, Katharina A1 - Wu, Yue A1 - Zhu, Shang A1 - Janssen, Jan A1 - Li, Calvin A1 - Foster, Ian A1 - Blaiszik, Ben T1 - 32 examples of LLM applications in materials science and chemistry: towards automation, assistants, agents, and accelerated scientific discovery N2 - Large Language Models (LLMs) are reshaping many aspects of materials science and chemistry research, enabling advances in molecular property prediction, materials design, scientific automation, knowledge extraction, and more. Recent developments demonstrate that the latest class of models are able to integrate structured and unstructured data, assist in hypothesis generation, and streamline research workflows. To explore the frontier of LLM capabilities across the research lifecycle, we review applications of LLMs through 34 total projects developed during the second annual Large Language Model Hackathon for Applications in Materials Science and Chemistry, a global hybrid event. These projects spanned seven key research areas: (1) molecular and material property prediction, (2) molecular and material design, (3) automation and novel interfaces, (4) scientific communication and education, (5) research data management and automation, (6) hypothesis generation and evaluation, and (7) knowledge extraction and reasoning from the scientific literature. Collectively, these applications illustrate how LLMs serve as versatile predictive models, platforms for rapid prototyping of domain-specific tools, and much more. In particular, improvements in both open source and proprietary LLM performance through the addition of reasoning, additional training data, and new techniques have expanded effectiveness, particularly in low-data environments and interdisciplinary research. As LLMs continue to improve, their integration into scientific workflows presents both new opportunities and new challenges, requiring ongoing exploration, continued refinement, and further research to address reliability, interpretability, and reproducibility. KW - Large Language Models KW - Machine Learning KW - Materials Design KW - Bonding Analysis KW - Phonons KW - Thermal properties PY - 2025 DO - https://doi.org/10.1088/2632-2153/ae011a SN - 2632-2153 VL - 6 IS - 3 SP - 1 EP - 34 PB - IOP Publishing AN - OPUS4-64019 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, X. A1 - Zhang, J. A1 - Wang, H. A1 - Rogal, J: A1 - Li, H.-Y. A1 - Wei, S.-H. A1 - Hickel, Tilmann T1 - Defect-characterized phase transition kinetics N2 - Phase transitions are a common phenomenon in condensed matter and act as a critical degree of freedom that can be employed to tailor the mechanical or electronic properties of materials. Understanding the fundamental mechanisms of the thermodynamics and kinetics of phase transitions is, thus, at the core of modern materials design. Conventionally, studies of phase transitions have, to a large extent, focused on pristine bulk phases. However, realistic materials exist in a complex form; their microstructures consist of different point and extended defects. The presence of defects impacts the thermodynamics and kinetics of phase transitions, but has been commonly ignored or treated separately. In recent years, with the significant advances in theoretical and experimental techniques, there has been an increasing research interest in modeling and characterizing how defects impact or even dictate phase transitions. The present review systematically discusses the recent progress in understanding the kinetics of defect-characterized phase transitions, derives the key mechanisms underlying these phase transitions, and envisions the remaining challenges and fruitful research directions. We hope that these discussions and insights will help to inspire future research and development in the field. KW - Kinetics KW - Atomistic models KW - Phase transitions KW - Defects PY - 2022 DO - https://doi.org/10.1063/5.0117234 SN - 1931-9401 VL - 9 IS - 4 SP - 1 EP - 42 PB - AIP CY - New York, NY AN - OPUS4-56507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Menga, D. A1 - Low, J. L. A1 - Li, Y.-S. A1 - Arcon, I. A1 - Koyutürk, B. A1 - Wagner, F. A1 - Ruiz-Zepeda, F. A1 - Gaberscek, M. A1 - Paulus, B. A1 - Fellinger, Tim-Patrick T1 - Resolving the Dilemma of Fe-N-C Catalysts by the Selective Synthesis of Tetrapyrrolic Active Sites via an Imprinting Strategy N2 - Combining the abundance and inexpensiveness of their constituent elements with their atomic dispersion, atomically dispersed Fe−N−C catalysts represent the most promising alternative to precious-metal-based materials in proton Exchange membrane (PEM) fuel cells. Due to the high temperatures involved in their synthesis and the sensitivity of Fe ions toward carbothermal reduction, current synthetic methods are intrinsically limited in type and amount of the desired, catalytically active Fe−N4 sites, and high active site densities have been out of reach (dilemma of Fe−N−C catalysts). We herein identify a paradigm change in the synthesis of Fe−N−C catalysts arising from the developments of other M−N−C single-atom catalysts. Supported by DFT calculations we propose fundamental principles for the synthesis of M−N−C materials. We further exploit the proposed principles in a novel synthetic strategy to surpass the dilemma of Fe−N−C catalysts. The selective formation of tetrapyrrolic Zn−N4 sites in a tailor-made Zn−N−C material is utilized as an active-site imprint for the preparation of a corresponding Fe−N−C catalyst. By successive low- and high-temperature ion exchange reactions, we obtain a phase-pure Fe−N−C catalyst, with a high loading of atomically dispersed Fe (>3 wt %). Moreover, the catalyst is entirely composed of tetrapyrrolic Fe−N4 sites. The density of tetrapyrrolic Fe−N4 sites is more than six times as high as for previously reported tetrapyrrolic single-site Fe−N−C fuel cell catalysts. KW - Fe-N-C catalyst KW - Precious-group metal-free catalyst KW - Tetrapyrrolic active-site KW - Single-site catalyst KW - Fuel cell KW - Carbon materials PY - 2021 DO - https://doi.org/10.1021/jacs.1c04884 SN - 1520-5126 VL - 143 IS - 43 SP - 18010 EP - 18019 PB - American Chemical Society AN - OPUS4-53657 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -