TY - THES A1 - Popiela, Bartosz T1 - Einfluss fertigungsbedingter Eigenspannungen auf die Betriebssicherheit von nassgewickelten Composite-Druckbehältern mit einem nichttragenden Liner N2 - Im Hinblick auf die globale Herausforderung der Energietransformation steigt der Bedarf an Möglichkeiten zur Energiespeicherung. Eine Technologie, die zunehmend in den Fokus rückt, ist die Energiespeicherung mittels komprimiertem Wasserstoffgas. Insbesondere für mobile und Transport-Anwendungen ist eine geringe Masse des Speichers vorteilhaft, weshalb vollumwickelte Composite-Druckbehälter des Typs 4 zum Einsatz kommen. Diese werden überwiegend im Nasswickelverfahren gefertigt, das durch zahlreiche Prozessparameter und physikalische Effekte charakterisiert wird. Die Wahl der Wickelprozessparameter sowie Schwankungen der Materialkennwerte beeinflussen den Eigenspannungszustand in der Composite-Struktur eines Druckbehälters. Somit wirken sie sich auch auf den Spannungszustand im Betrieb aus. Die vorliegende Dissertation beinhaltet Untersuchungen des Einflusses von fertigungsbedingten Eigenspannungen auf die Sicherheit von Composite-Druckbehältern mit nichttragendem Kunststoff-Liner. Ziel ist es, das mechanische Verhalten von Composite-Druckbehältern besser zu verstehen und deren Sicherheitsniveau sowie Konkurrenzfähigkeit weiter zu steigern. Schwerpunkte der Arbeit sind experimentelle Untersuchungen der Eigenspannungsentstehung und -entwicklung sowie deren Einfluss auf die Behälter-Sicherheit. Im Fokus befindet sich die Exploration von Möglichkeiten zur Verbesserung der Zuverlässigkeit der Behälter durch Variation der Fertigungsparameter und eine Konditionierung nach der Fertigung. Der Eigenspannungszustand wird in numerischen Simulationen sowie mit dem zerstörenden Bohrlochverfahren charakterisiert. Die Überwachung der Spannungsumlagerung während einer Konditionierung unter Zeitstandbelastung erfolgt mit eingebetteten faseroptischen Sensoren, die später zur Dehnungsmessung in zerstörenden, langsamen Berstprüfungen eingesetzt werden. Zur Vertiefung des Verständnisses des Versagensverhaltens der verwendeten 6,8 l-Druckbehälter wird die Finite-Elemente-Methode eingesetzt. Darüber hinaus werden Qualitätsuntersuchungen der Composite-Struktur mittels Mikro-Computertomographie und Impuls-Echo-Verfahren beschrieben. Die Ergebnisse der Untersuchungen zeigen, dass eine Steigerung der Zuverlässigkeit durch eine gezielte Innendruckbeanspruchung der gewickelten Behälter nahezu kostenneutral möglich ist. Dies wird im Rahmen der Arbeit anhand eines Baumusters demonstriert. Darüber hinaus wird die Verbesserung der Zuverlässigkeit der Behälter im Rahmen einer Konditionierung unter Zeitstandbelastung vertieft diskutiert. Diese stellt eine weiterführende Möglichkeit dar, das Behälterverhalten positiv zu beeinflussen und das Sicherheitsniveau zu steigern. N2 - Considering the global challenge of energy transformation, the demand for energy storage solutions is increasing. One of the technologies, which is gaining attention, is the storage of hydrogen gas under high operating pressures. Particularly for on-board and transport applications, lightweight storage systems are advantageous. Therefore, fully wrapped composite pressure vessels of Type 4 are increasingly used. These are mostly manufactured using the wet filament winding process, which is characterized by numerous process parameters and physical effects. The choice of winding process parameters and variations in material properties influence the residual stress state in the finished component and thus also the stress state under operational loads. This dissertation includes insights into the impact of manufacturing-induced residual stresses on the safety of Type 4 pressure vessels, which contribute to a deeper understanding of the mechanical behavior of composite pressure vessels and support the further enhancement of safety levels and competitiveness. The work focuses on experimental investigations of the induction and development of residual stresses and their impact on the safety of the composite pressure vessels. A core of the dissertation is an exploration of the possibilities to improve pressure vessel performance through variation of manufacturing parameters and conditioning after manufacturing. The residual stress state is characterized in numerical simulations as well as with the destructive hole-drilling method. Embedded fiber optic sensors are used for the monitoring of stress redistribution during conditioning. The fiber optic sensors are later used for strain measurement in destructive, slow burst tests. Finite element analyses are performed to deepen the understanding of the failure behavior of the used 6.8-liter pressure vessels. Additionally, quality investigations of the composite structure using micro-computed tomography and impulse-echo ultrasonic propagation imaging are described. The results of the investigations show that an increase in performance is possible through targeted internal pressure regulation during the winding process pressure vessels. This is demonstrated almost cost-neutrally, i.e., without increasing process time and material usage. Furthermore, the improvement of vessel performance through conditioning under increased pressure and temperature is discussed in depth. This represents a further possibility to favorably influence vessel behavior and enhance safety levels. KW - Composite KW - Druckbehälter KW - Eigenspannung KW - Faserverstärkter Kunststoff KW - Nasswickelverfahren PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:co1-opus4-72383 DO - https://doi.org/10.26127/BTUOpen-7238 SP - 1 EP - 153 CY - Cottbus, Deutschland AN - OPUS4-65348 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tuma, Dirk T1 - Trace-level ammonia-water interactions in hydrogen: challenges in purity analysis using Optical-Feedback Cavity-Enhanced Absorption Spectroscopy (OF-CEAS) N2 - ISO 14687 defines a threshold of 100 ppb ammonia for hydrogen to be used in fuel cells. This work presents analysis methods using OF-CEAS and discusses moisture-related surface effects on the results. T2 - Gas Analysis 2026 CY - Paris, France DA - 27.01.2026 KW - OF-CEAS KW - Ammonia KW - Moisture effects PY - 2026 AN - OPUS4-65480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Popiela, Bartosz T1 - Einfluss ausgewählter Fertigungsparameter auf die Sicherheit von Composite-Druckbehältern N2 - In dem Vortrag wurde der Einfluss ausgewählter Fertigungsparameter auf die Sicherheit von Composite-Druckbehältern diskutiert. Die Inhalte stammen aus einem Projekt im Rahmen des BTU-BAM Graduiertenkollegs "Trustworthy Hydrogen". Darüber hinaus umfasst der Foliensatz eine Kurzvorstellung der Aktivitäten des Fachbereichs 3.5 im Bereich der Wasserstofftechnologien. T2 - Workshop "Wasserstoff in der Luftfahrt: Wasserstoffspeicherung und -transport für Luftfahrt und darüber hinaus" CY - Berlin, Germany DA - 11.02.2026 KW - Composite KW - Druckbehälter KW - Fertigung PY - 2026 AN - OPUS4-65498 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Campari, Alessandro A1 - Konert, Florian A1 - Razavi, Nima A1 - Sobol, Oded A1 - Alvaro, Antonio T1 - Hydrogen-assisted cracking: A deep learning approach for fractographic analysis N2 - Hydrogen handling equipment suffers from interaction with their operating environment, which degrades the mechanical properties and compromises component integrity. Hydrogen-assisted cracking is responsible for several industrial failures with potentially severe consequences. A thorough failure analysis can determine the failure mechanism, locate its origin, and identify possible root causes to avoid similar events in the future. Postmortem fractographic analysis can classify the fracture mode and determine whether the hydrogen-metal interaction contributed to the component’s breakdown. Experts in fracture classification identify characteristic marks and textural features by visual inspection to determine the failure mechanism. Although widely adopted, this process is time-consuming and influenced by subjective judgment and individual expertise. This study aims to automate fractographic analysis through advanced computer vision techniques. Different materials were tested in hydrogen atmospheres and inert environments, and their fracture surfaces were analyzed by scanning electron microscopy to create an extensive image dataset. A pre-trained Convolutional Neural Network was finetuned to accurately classify brittle and ductile fractures. In addition, Grad-CAM interpretability method was adopted to identify the image regions most influential in the model’s prediction and compare the saliency maps with expert annotations. This approach offered a reliable data-driven alternative to conventional fractographic analysis. KW - Failure analysis KW - Fractographic analysis KW - Hydrogen embrittlement KW - Material compatibility PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-646610 DO - https://doi.org/10.1016/j.commatsci.2025.114366 SN - 0927-0256 VL - 262 SP - 1 EP - 16 PB - Elsevier Science CY - Amsterdam [u.a.] AN - OPUS4-64661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design N2 - My talk covered, among other things, robust data generation for machine learning. It showed how heuristics can be used within machine learning models and how they might also be extracted from machine learning models. Beyond this, I showed an automated pipeline for training machine learning potentials. T2 - Workshop on AI in Sustainable Materials Science CY - Düsseldorf, Germany DA - 27.01.2026 KW - Automation KW - Digitalisation KW - Materials Design KW - Thermal Conductivity KW - Chemical bonding KW - Materials Acceleration Platforms PY - 2026 AN - OPUS4-65427 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - George, Janine T1 - Robust Data Generation, Heuristics and Machine Learning for Materials Design N2 - My talk covered, among other things, robust data generation for machine learning. It showed how heuristics can be used within machine learning models and how they might also be extracted from machine learning models. Beyond this, I showed an automated pipeline for training machine learning potentials. T2 - Seminar Gruppe Stephan Roche CY - Barcelona, Spain DA - 22.01.2026 KW - Automation KW - Machine Learning KW - Materials Acceleration Platforms KW - Thermal Conductivity KW - Phonons KW - Bonding Analysis PY - 2026 AN - OPUS4-65428 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eberwein, Robert A1 - Ustolin, Federico A1 - Zervaki, Anna A1 - Okpeke, Bright A1 - Harwege, Finn A1 - Tugnoli, Alessandro T1 - NICOLHy - 4th Stakeholder Advisory Board Meeting N2 - The NICOLHy project aims to develop a novel insulation concept based on Vacuum Insulation Panels (VIP) that enables the safe, cost- and energy efficient storage of large quantities of LH2. Such large scale LH2 storage technology is necessary for establishing a hydrogen economy with dimensions between 40.000 m³ and more than 200.000 m³ of LH2. However, new design concepts are needed because the currently available technologies used in small and medium storages today are not suitable for up-scaling. The main problems prohibiting the up-scaling are the long production time due to the process chain, the low failure tolerance and the spherical shape, which reduces the payload in technical applications by up to 50% compared to other shapes. The novel concept will change these conditions by a system which is modular, open-form, time-and cost efficient while production, operation and service, multi-failure tolerant and applicable for onshore and offshore applications. The presentations shows details to the concept and presents several safety concerns the project has to deal with. T2 - NICOLHy 4th Stakeholder Advisory Board Meeting CY - Hamburg, Germany DA - 23.01.2026 KW - LH2 KW - Insulation KW - Life cycle assessment KW - Tank PY - 2026 AN - OPUS4-65437 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hübner, Martin A1 - Dittmann, Florian A1 - Kromm, Arne A1 - Varfolomeev, Igor A1 - Kannengiesser, Thomas T1 - Enhancement of the fatigue strength by application of a low transformation temperature (LTT) welding consumable N2 - Low transformation temperature (LTT) welding consumables offer a possibility to enhance fatigue strength in welded components without post-treatment. By lowering the martensite start temperature (MS), the volume expansion during transformation near ambient temperature reduces welding related tensile residual stresses in fatigue-critical areas. To evaluate this effect, longitudinal stiffeners were used, a LTT and conventional filler serve as welding consumable, also high frequency mechanical impact (HFMI) treatment was carried out. Three single-pass and six additional-pass sample series were investigated on residual stress and fatigue strength. The additional welds were applied in fatigue crack critical areas with different weld shapes, achieved by varying welding parameters. Mechanical tests on reference samples evaluated the properties of the diluted LTT welds. Although reduced toughness was observed, no fatigue cracks occurred in LTT single-pass weld roots. The fatigue strength at two million cycles increased from 81 MPa to 121 MPa compared to conventional welds, while HFMI reached 146 MPa. With an additional LTT weld pass the results varied from 138 MPa to 196 MPa, depending to the shape and residual stress state. The results show that LTT fillers effectively enhance fatigue performance, and that weld geometry and parameter selection are as critical as the chemical composition for maximizing the LTT effect. CY - Genua, Italy DA - 22.06.2025 KW - Low transformation temperature (LTT) KW - Martensite start temperature KW - Residual stress KW - Longitudenal stiffener KW - Fatigue strength PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654520 DO - https://doi.org/10.1007/s40194-026-02356-8 SP - 1 EP - 14 PB - Springer Nature AN - OPUS4-65452 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Radnik, Jörg T1 - The role of Critical Raw Materials in Advanced Materials for the Energy Transition N2 - Based on the UBA report “Advanced materials for energy transition” by Xenia Knigge and Jörg Radnik the role of critical raw materials is discussed. Critical raw materials are needed in main fields of the energy transition, like photovoltaic, fuel cells, wind energy, and batteries. For the optimisation of the use of these materials different scenarios are discussed like (i) decreasing the needed amount of raw materials, (ii) searching for alternatives, (iii) using technologies which do not require critical raw materials, (iv) increasing the recycling rates, and (v) expanding the raw material sources. T2 - IRISS policy dialogue CY - Online meeting DA - 12.01.2026 KW - Solar Cells KW - Fuel cells KW - Batteries KW - Multi-use materials PY - 2026 AN - OPUS4-65451 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Khella, Shady T1 - Integration of Information Models Using Semantic Web Technologies Within the Mixed Reality Data Hub N2 - Engineering information is distributed across heterogeneous data models, ontologies, and reference data libraries (RDLs), which complicates interoperability, hinders workflow automation, and limits the deployment of industrial Mixed Reality (MR) applications. This work uses DEXPI Process semantics and Semantic Web technologies to align and integrate these heterogeneous sources into a single knowledge graph. The resulting graph provides a queryable semantic layer that enables consistent cross-source access to engineering information and supports MR application development. Beyond integration, the semantic graph enables automation of process design workflows. We demonstrate this using a basic engineering use case in which alternative flowsheet design options are generated from a semantically modeled block flow diagram (BFD). T2 - DEXPI Days 1.0 CY - Frankfurt am Main, Germany DA - 20.01.2026 KW - Mixed Reality KW - Data Integration KW - Semantic Web Technologies KW - DEXPI PY - 2026 AN - OPUS4-65489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Eberwein, Robert T1 - NICHOLHy - Novel insulation concepts for liquefied hydrogen storage tanks N2 - Liquefied Hydrogen is a promising energy carrier for the flexible import of energy to Europe. But, tanks in the relevant scale of 40 000 to 200 000 m³ do not exist yet. The upscaling of liquid hydrogen (LH2) storage tanks from the current largest tank of 4700 m³ requires a new concept for thermal insulation. NICOLHy studies novel concepts based on multiple layers of vacuum insulation panels (VIPs). Current LH2 tanks rely on the intactness of a single vacuum layer that covers the whole tank. The multilayered VIP systems offer redundancy and improve manufacturability. The Article describes the progress within the project. KW - LH2 KW - Insulation KW - Tanks PY - 2026 UR - https://www.europeanenergyinnovation.eu/content/files/2025/12/EEI-Magazine---Winter-2025-Digital-Version-Spreads-2.pdf SN - 3049-5431 VL - 2026/1 SP - 33 EP - 33 PB - Pantograf Media Ltd. CY - London AN - OPUS4-65481 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharpmann, Philippa A1 - Leonhardt, Robert A1 - Schmidt, Anita A1 - Kowal, Julia A1 - Tichter, Tim A1 - Krug von Nidda, Jonas T1 - Exploring restrictive overdischarge cycling as a method to accelerate characteristic ageing in lithium-ion cells N2 - This study presents a test protocol that greatly accelerates the ageing process of lithium-ion battery cells comprising a positive electrode of nickel manganese cobalt oxide while preserving their characteristic degradation upon cyclic ageing. Applying a repetitive restricted overdischarge, resulting in a depth of discharge larger than 100%, a capacity loss of 20% is achieved over five times faster compared to conventional cycling. The well-known overdischarge degradation phenomenon of copper current collector dissolution is deliberately prevented by setting a discharge cutoff voltage above the theoretical threshold of copper oxidation. Hence, the accelerated degradation can be primarily connected to solid electrolyte interphase growth. A comparative assessment of the ageing dynamics using electrochemical impedance spectroscopy and differential voltage analysis hints towards similar, characteristic degradation processes during accelerated and conventional ageing. A post-ageing examination of the electrical behaviour (i.e., coulombic and energy efficiency, capacity fade) under reference conditions reveals very little to no lasting damages caused by overdischarging. Additionally, post-mortem analysis discloses no increased copper dissolution when comparing cells subjected to accelerated and conventional ageing. Generally, the developed ageing method appears suitable for providing cells with a defined state of health at a reasonable timescale without altering the main degradation mechanisms significantly. KW - Lithium-ion cell KW - Accelerated ageing KW - Overdischarge KW - Degradation processes KW - Differential voltage analysis KW - Electrochemical impedance spectroscopy PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-650917 DO - https://doi.org/10.1016/j.jpowsour.2025.239072 SN - 0378-7753 VL - 665 SP - 1 EP - 9 PB - Elsevier B.V. AN - OPUS4-65091 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cornelio, Andrea T1 - NASICON Electrolytes for Room-Temperature Sodium-Sulfur Batteries: from Material Synthesis to Cell Testing N2 - Solid electrolytes (SE) allow to employ alkali-metal negative electrodes (NE) in new cell concepts, increasing energy density and safety of batteries for stationary and portable applications. The aim of this research is to develop a novel NASICON (NA Super Ionic CONductor) electrolyte for room-temperature (RT) sodium-sulfur (Na-S) cells employing a liquid sodium-potassium (Na-K) alloy at the SE/NE interface. The Na-K alloy can improve the interfacial contact between the sodium-metal NE and the SE. T2 - Batterieforum Deutschland 2026 CY - Berlin, Germany DA - 20.01.2026 KW - NASICON KW - Solid Electrolytes KW - Synthesis KW - Characterization KW - Na batteries KW - Electrochemical testing PY - 2026 AN - OPUS4-65423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wille, Frank T1 - BAM-Testzentrum Wasserstoffsicherheit - Reallabore und Materialprüfung N2 - Der Vortrag gibt einen kompakten Überblick über das BAM-Testzentrum Wasserstoffsicherheit und seine Rolle bei der Forschung, Prüfung und Entwicklung sicherheitsrelevanter Technologien entlang der gesamten Wasserstoff-Wertschöpfungskette. Das Kompetenzzentrum H2Safety@BAM vereint wissenschaftliche Expertise, einmalige Infrastruktur und praxisnahe Reallabore, um Vertrauen in Wasserstoff als zukünftigen Energieträger zu schaffen. Im Mittelpunkt steht das Testgelände für Technische Sicherheit, das mit 12 km² zu den umfassendsten europäischen Einrichtungen für Sicherheitstests im Realmaßstab zählt. Dazu gehören eine Wasserstofftankstelle, Wasserstoffnetze im Reallabormaßstab, Prüfstände für Kryotechnik, Brand- und Explosionsversuche sowie eine im Bau befindliche Anlage zur Druckbehälterprüfung. Die Infrastruktur ermöglicht Freistrahlversuche, Jetflame-Tests sowie Untersuchungen für 1000-bar-Systeme. Im Reallabor Wasserstoffnetze werden Materialien, Gasqualitäten, dynamische Strömungsszenarien und Komponenten unter realistischen und kritischen Bedingungen untersucht, um die sichere Integration von Wasserstoff in bestehende und neue Pipelineinfrastrukturen zu ermöglichen. Parallel dazu schafft das Reallabor Wasserstofftankstelle die Grundlage für neue digitale Methoden der Qualitätsinfrastruktur von Sensornetzwerken über Echtzeit-Datenerfassung bis zur Anlagenüberwachung. Ein Beispiel ist die Optimierung von Betankungsprozessen mittels Digital Twin, die eindrucksvoll demonstriert, wie die Sicherheit bei Schnellbetankungen aufgezeigt werden kann. Mit Blick auf die Zukunft adressiert die BAM zudem die Sektorenkopplung. Datengetriebene Ansätze, KI und digitale Zwillinge sollen den sicheren und effizienten Betrieb von Elektrolyse, Energiespeichern und Wasserstoffanwendungen vernetzt unterstützen. Insgesamt zeigt die Präsentation, dass die BAM eine zentrale Institution für die sichere Transformation hin zu einer Wasserstoffwirtschaft ist - mit exzellenter Infrastruktur, praxisnahen Reallaboren und tiefgreifender Forschungskompetenz. T2 - Wasserstofftour durch die Regionen 2026 CY - Cottbus, Germany DA - 11.02.2026 KW - Reallabor KW - QI-Digital KW - Materialprüfung KW - Elektrolyse KW - Wertschöpfungskette KW - Testgelände PY - 2026 AN - OPUS4-65537 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kästle, Emanuel D. A1 - Duffner, Eric A1 - Popiela, Bartosz A1 - Ghaznavi, Ali T1 - Monitoring Failure of Composite Pressure Vessels with Acoustic Emissions N2 - Two carbon fiber reinforced type IV pressure vessels are subjected to step-wise pressurization until burst, while monitored using acoustic emissions (AE). Unlike most prior studies, AE data is collected throughout the entire damage progression. The vessels, manufactured with differing parameters, failed in distinct composite layers – A-type in the hoop layers and B-type in the helical layers. The AE signals are evaluated to study material degradation and identify fiber breaks as signs of critical damage accumulation. The signals are distributed randomly across the surface, with localized accumulation only minutes before rupture, close to the rupture plane. The difference in manufacturing parameters did not result in any clear difference in the AE activity. Felicity and Shelby ratios show consistent decline with increasing pressure, suggesting potential for damage assessment and burst prediction. It is discussed how these ratios are affected by coupling quality of the AE sensors, the shape of the pressurization profile and prior loadings. Different signal features based on the amplitude and the frequency content are extracted for a classification into failure mechanisms. Based on previous studies, AE signals corresponding to fiber breaks have a characteristic high-frequency spectrum and show a delay in occurrence, with an increase in the number of breaking fibers towards the end of the experiment. Indeed, high frequency signals tend to occur later and signals in specific peak-frequency ranges (350 – 400 kHz,  500 kHz) somewhat resemble the expected behavior. However, the dataset is too variable and too incongruent for any clear interpretations. Likely reasons are signal propagation effects, the complex composite structure, simultaneous occurrence of signals and measurement uncertainties. A review of relevant studies is provided to show that similar issues affect also previous works. Successfully identifying fiber breaks in large-scale, complex composite structures based on AE data, and turning this into an applicable health-monitoring technique, therefore remains a challenge. KW - Acoustic emission testing KW - Composite pressure vessels KW - Damage classification in fiber reinforced polymers KW - Felicity ratio KW - Composite failure PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654852 DO - https://doi.org/10.1007/s10921-025-01319-1 SN - 0195-9298 VL - 45 IS - 1 SP - 1 EP - 19 PB - Springer Science and Business Media LLC AN - OPUS4-65485 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dixneit, J. A1 - Gibmeier, J. A1 - Kromm, Arne A1 - Schubnell, J. A1 - Lang, F. A1 - Loebich, F. A1 - Carl, E.-R. A1 - Ya, W. T1 - Residual stress distribution of a large component manufactured by AM-DED-Arc from high-strength weld filler material X90 N2 - Currently, DED-Arc manufactured components are not covered by design guidelines, and design factors such as residual stress factors are not defined for such components. This hinders industrial use, especially for components with a remaining surface waviness required by industry. For the first time the stress state of a high-strength, low-alloy, large-scale DED-Arc component was characterised in the as-built state and after cutting off the component from the substrate plate. Complementary methods of residual stress analyses were applied to gain a holistic insight into the residual stress distributions of a thick-walled part. In the as-built state, direction-dependent and position-dependent tensile residual stresses were found for the component at the level of the yield strength of the part. The additive manufacturing strategy continuous spiral deposition has no significant influence on the residual stresses in bead threshold area compared to the residual stresses of the remaining component. For this case, bead threshold is no structural imperfection. By removing the part from the substrate plate, the residual stresses are significantly redistributed. Tensile residual stresses are then present at a moderate level. Compressive residual stresses were determined in the volume of the deposited material. The general consideration of ‘‘high’’ tensile residual stresses in such thick-walled components is rather conservative. Therefore, design guidelines should take the manufacturing condition into account. KW - AM-DED-Arc KW - Residual stress KW - High strength steel PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655239 DO - https://doi.org/10.1177/03093247251406876 SN - 2041-3130 SP - 1 EP - 18 PB - SAGE AN - OPUS4-65523 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cerny, Alain T1 - Engineering Activated Carbon via Chemical Vapor Deposition for High-Performance Core-Shell Carbon Anodes in Sodium-Ion Batteries N2 - Rising demand for sustainable energy storage has renewed interest in sodium-ion batteries (SIBs) as alternative to lithium-ion batteries. Although hard carbon and related materials are common SIB-anodes, the correlation between its structure and ion storage mechanism remains unclear.[1] As shown recently, the pore design is essential to block the formation of excessive solid electrolyte interphase (SEI) and allows the formation of pseudo-metallic clusters inside the pores.[2,3] Adjusting the diameter of the pore entrance, enables a reversible low-potential plateau (< 0.1 V), which significantly enhances the capacity (potentially up to 450-500 mAh/g) compared to graphite (Qtheo = 372 mAh/g) in Li-ion batteries.[2] Activated carbon (AC) is a low-cost material with abundant micropores and high surface area, making it a promising anode candidate for SIBs. However, its performance is often hindered by structural disorder and excessive SEI-formation. Hence, mitigating active-species loss is essential to achieve high specific capacities (> 300 mAh g-1).[3] The aim herein was to investigate the relationship between the properties of the AC and the CVD-conditions required to achieve an efficient SIB-anode. This study introduces an optimized chemical vapor deposition (CVD) method to modify various, highly porous commercial ACs aiming towards core-shell carbons, consisting of a porous core and a non-graphitic CVD-shell.[3] The ACs were treated via CVD and characterized using a range of techniques including gas physisorption, small-angle x-ray scattering and X-ray diffraction. The electrochemical properties of the different materials, prior and after CVD-coating, were analysed in half cells vs. Na-metal. After coating, gas physisorption confirmed a significantly lower surface area for the materials. Depending on the porosity of the material, a longer CVD-time was necessary to fully coat the particles. The successful formation of core-shell carbons enables separation of the storage mechanism from SEI-formation. The CVD-process enables precise control over the microstructure of the carbon material, allowing to enhance the reversible Na-storage capacity, e.g., from 107 mAh g-1 to 353 mAh g-1 while significantly reducing initial Coulombic losses by 73%. The greatly increased low-potential capacity verifies the formation of an electrolyte-tight CVD shell enabling Na-storage in the porosity of the core. The established link between porosity, CVD-parameters, and performance guides optimization for future materials. T2 - Batterieforum 2026 CY - Berlin, Germany DA - 20.01.2026 KW - Sodium-Ion Battery KW - Carbon KW - Chemical Vapour Deposition PY - 2026 AN - OPUS4-65510 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mieller, Björn A1 - Fellinger, Tim-Patrick T1 - Berlin Battery Lab - Vom Material zur Zelle - Batterieinnovation aus Berlin N2 - Das Berlin Battery Lab (BBL) vereint exzellente Materialforschung, modernste Analytik und gezielten Technologietransfer. Als gemeinsames Labor von BAM, HZB und der Humboldt Universität zu Berlin entwickeln wir zukunftsfähige Natrium-Ionen- und Metall-Schwefel-Batterien – von der Materialidee bis zur funktionsfähigen Zelle. T2 - Batteriaforum Deutschland CY - Berlin, Germany DA - 20.01.2026 KW - Batterie KW - Kooperation KW - Natrium-Ionen KW - BBL PY - 2026 AN - OPUS4-65410 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kaiser, Sebastian T1 - Bestimmung des Temperaturfeldes beim Schweißen im Betrieb an Wasserstoff-Ferngasleitungen N2 - Grüner Wasserstoff wird als zukünftiger Energieträger eine wichtige Rolle bei der Dekarbonisierung spielen. Sein großtechnischer Transport über große Entfernungen wird über ein Wasserstoff-Pipelinennetz erfolgen. Ein solches Netz erfordert regelmäßig Schweißarbeiten zu Reparatur-, Wartungs- oder Erweiterungszwecken. Im Erdgasnetz ist es gängige Praxis, Schweißarbeiten während des Betriebs auszuführen, da es technisch und wirtschaftlich äußerst schwierig ist, eine Pipeline außer Betrieb zu nehmen. Im Fall von Wasserstoffpipelines ist hierbei jedoch zu beachten, dass Wasserstoff in den Pipelinestahl absorbiert werden kann. Dies kann zu einer Beeinträchtigung der Materialeigenschaften oder sogar zum Versagen der Pipeline führen, da die bekannten Effekte der wasserstoffinduzierten Versprödung und der wasserstoffunterstützten Rissbildung auftreten können. Die Wasserstoffaufnahme ist dabei wesentlich von den beim Schweißen auftretenden erhöhten Temperaturen abhängig. Um genaue Kenntnisse der zu erwartenden Temperaturen zu erlangen, wurden Schweißversuche an Ersatzgeometrien durchgeführt und Temperaturverläufe an diesen gemessen. Basierend auf den Temperaturmessungen sollen im weiteren Verlauf in Zusammenarbeit mit der TU Graz Temperaturfelder sowie die resultierende Wasserstoffaufnahme und -diffusion mittels FEM berechnet werden. T2 - Forschungsseminar OvGU-Magdeburg CY - Magdeburg, Germany DA - 18.02.2026 KW - Pipeline KW - Schweißen KW - Wasserstoff PY - 2026 AN - OPUS4-65565 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gook, Sergej A1 - Biegler, Max A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Integration of hybrid laser-arc and narrow gap submerged arc welding for cost-effective joining of 80 mm thick S355ML steel plates N2 - This paper presents the results of developing a cost-effective, robust process for welding thick steel plates. Welding trials were performed on S355ML structural steel plates with a thickness of 80 mm. A specially designed U-shaped joint preparation with a 45 mm root face was proposed to enable thick welds to be welded using a combined technique. In the developed process, a hybrid laser arc weld (HLAW) is performed as the first pass. Subsequently, narrow-gap submerged arc welding (NG-SAW) is applied to the opposite side using a multi-layer technique. The weld cross-section is completed using a reliable overlap of both the HLAW and NG-SAW welds. This method achieves a 2.9-fold reduction in weld volume and filler material consumption, as well as shorter production times for thick-walled welds. Further advantages of the process combination include eliminating the need to form the root of the HLAW weld and the absence of a backing support. The applied process parameters ensure that the maximum heat input does not exceed 5 kJ/mm, leading to uniform hardness across the weld metal and heat-affected zone (HAZ). Impact toughness testing at −40 °C demonstrated excellent performance, with Charpy V-notch energies of 138 ± 45 J in the arc-dominated region and 65 ± 12 J in the critical laser-dominated zone of the HLAW weld. In addition, the NG-SAW weld exhibited an average Charpy V-notch energy of 274 ± 5 J, confirming excellent low-temperature toughness of the fill passes. Owing to its high process stability and practical applicability, the proposed welding approach shows high potential for integration into the fabrication of thick-walled offshore constructions. KW - Hybrid laser arc welding KW - Narrow gap submerged arc welding KW - Low carbon structural steel KW - Fusion zone size KW - Microstructure KW - Impact absorbed energy KW - Hardness PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655627 DO - https://doi.org/10.1016/j.optlastec.2026.114796 SN - 0030-3992 VL - 197 SP - 1 EP - 12 PB - Elsevier Ltd. AN - OPUS4-65562 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Semenova, Aleksandra A1 - Spitzer Sra, Stefan H. A1 - Dvorakova, Barbora A1 - Askar, Enis A1 - Funnemann, Patrick A1 - Hermanns, Roy T.E. A1 - Jankuj, Vojtech A1 - Vignes, Alexis A1 - Kuracina, Richard A1 - Szabova, Zuzana A1 - Norman, Frederik A1 - Gabel, Dieter A1 - Danzi, Enrico A1 - Makarova, Ekaterina A1 - Lorenzon, Ivan A1 - Toman, Adrian A1 - Adamus, Wojciech A1 - Hessels, Conrad T1 - Towards standardized safety protocols for iron-based energy carriers: International alignment through round robin testing on safety characteristics N2 - Background Iron powder appears to be a promising solution for long-term energy storage and (inter-) continental transport, as it is safe to store and does not require energy to maintain its state, unlike, for instance, liquefied hydrogen. However, while the fundamental research is well underway, large-scale implementation is still in its early stages, with a growing number of promising demonstrators emerging. Methods This article contributes to the large-scale implementation of iron as an energy carrier by presenting a round-robin test of four iron powders currently used in research and larger-scale demonstrators. These powders were tested on their safety characteristics in the standard 20 L apparatus across eight European countries. Results The resulting data are intended to support future standardization efforts using different iron samples as standardized fuel. All tested powders were classified either as non-explosible or as belonging to the category of marginally explosible dusts (Class 1). This provides a clear picture of the level of explosion protection measures that need to be considered for the safe use of iron powders in energy carrier applications. Conclusions Along with that, the study detected variations in the results and pointed to shortcomings in the current standards that may cause such discrepancies. These findings emphasize the importance of improving testing procedures to support standardization and ensure the safe use of iron powder as an energy carrier using an a-priori-approach rather than subsequent testing. KW - Explosion protection KW - Energy carrier KW - Safety characteristics PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655761 DO - https://doi.org/10.12688/openreseurope.22839.1 SN - 2732-5121 VL - 6 SP - 1 EP - 20 PB - F1000 Research Ltd AN - OPUS4-65576 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hajhariri, Aliasghar A1 - Eberwein, Robert A1 - Camplese, Davide A1 - Scarponi, Giordano Emrys A1 - Cozzani, Valerio A1 - Seidlitz, Holger T1 - Cryogenic storage safety: Experimental evaluation of insulation under extreme conditions N2 - Hydrogen is recognized as a keystone of the global energy transition, offering a clean, high-energy-density energy carrier ideal for storage and transportation. Among various storage options, liquid hydrogen (LH2) is especially advantageous for both mobile and stationary applications. However, ensuring the safety and performance of LH2 storage systems under extreme thermal conditions, such as fire exposure, remains an engineering challenge. This study introduces an experimental framework, called the Cryogenic High-Temperature Thermal Vacuum Chamber (CHTTVC), designed to investigate the thermal-hydraulic response of vacuum-insulated cryogenic tanks under fire-like conditions. The apparatus enables evaluation of insulation performance, such as perlite and multilayer insulation (MLI), with a focus on thermal degradation, heat ingress, and vacuum stability. Results indicate that combustible MLIs undergo substantial thermal degradation, leading to heat ingress rates of up to 6.5 kW and the formation of hazardous combustion by-products. In contrast, non-combustible MLIs and bulk insulation materials restrict heat ingress to approximately 3 kW while more effectively preserving vacuum integrity. Combustible MLIs also exhibit pronounced pressure increases in the evacuated section, reaching ∼6 × 104 Pa, nearly six times higher than those observed for non-combustible counterparts. Analysis of effective emissivity further reveals an enhancement in radiative heat transfer, approximately five times, for combustible MLIs following degradation. Additionally, marked thermal stratification develops under both nominal and extreme heat loads, with temperature gradients approaching 10 °C per 100 mm during sustained thermal exposure. KW - Multi-Layer Insulation KW - Cryogenic Storage KW - Safety PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655380 DO - https://doi.org/10.1016/j.jlp.2026.105961 SN - 0950-4230 VL - 101 SP - 1 EP - 20 PB - Elsevier Ltd. AN - OPUS4-65538 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayat, Mehmet E. A1 - Huber, C. A1 - Kipphardt, Heinrich A1 - Tiebe, Carlo A1 - Engelhard, Carsten T1 - Towards a sensor-based methodology to determine online calorific values of H2-enriched natural gases in the grid N2 - The German National Hydrogen Strategy (NWS) envisions a transition towards a hydrogen-based energy grid. However, due to the material incompatibility of existing pipeline infrastructure for amounts of hydrogen higher than 10 cmol/mol, many system components of the existing grid must be replaced with significant costs and considerable time investments. Given these constraints, the admixture of hydrogen into natural gas (NG) to create a hydrogen-enriched NG blend has been designated as a transitional technology. The NWS supports this approach on a regional and time-limited basis, but clearly states that it is not intended as a permanent solution. Nevertheless, the conversion to a fully hydrogen-based grid is expected to take several decades. During this transitional phase, precise process analytical monitoring of hydrogen amounts in the NG blend is essential to ensure both energy efficiency via calorific value control and operational safety. These procedures require cost-effective, robust, and reliable sensor technologies capable of real-time, in situ/on-site quantification of hydrogen amounts in NG. In response to this need, we have advanced a physical sensing approach utilizing an oscillating cantilever in collaboration with Truedyne Sensor AG. This sensor system enables quantification of hydrogen amounts, direct calorific value determination as well as display of beneficial gas properties, like density, viscosity, and thermal conductivity. Moreover, the enhanced cantilever system enables direct physical sensing and can also be operated in a quasi-binary mode. We performed comparative evaluations against two benchmark sensor systems to validate the developed technology. One utilizes chemical sensing, and the other operates on thermal conductivity measurements for hydrogen quantification. Through standardized testing, we demonstrated that the cantilever-based sensor offers both high effectiveness and competitive performance compared to current state-of-the-art technologies for accurate hydrogen detection in natural gas and precise determination of its calorific value. T2 - Gas Analysis 2026 CY - Paris, France DA - 27.01.2026 KW - Hydrogen KW - Natural Gas KW - Sensor KW - Calorific Value KW - Grid PY - 2026 AN - OPUS4-65505 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Plarre, Rudy T1 - Wirksamkeitsbewertung von Holzschutzmitteln N2 - Der Holzschutz in Deutschland ist durch DIN 68800 geregelt. Die Anwendung von Holzschutzmitteln zum Schutz verbauten Holzes ist dabei eine Möglichkeit. Voraussetzung für den Gebrauch von Holzschutzmitteln ist deren Zulassung nach Biozidgesetz. Der Vortrag beschreibt die Vorgehensweise bei der Wirksamkeitsbewertung von Holzschutzmitteln im Rahmen der europäischen Biozidzulassung. Die Wirksamkeitsbewertung erfolgt durch biologische Prüfungen anhand von europäischen Normen getrennt nach Zielorganismen. Je nach späterer Gebrauchssituation des mit Holzschutzmitteln behandelten Holzes sind definierte Alterungsverfahren nach Norm der eigentlichen biologischen Prüfung vorzuschalten. Das Prüfergebnis des widerstandsfähigsten Organismus legt die zum Schutz des Holzes notwenige Konzentration und Einbringmenge des Holzschutzmittel fest. T2 - Fortbildung für Angehörige von Bundesbehörden organsiert durch die BAuA CY - Online meeting DA - 12.02.2026 KW - Holzschutzmittel KW - Wirksamkei KW - Biozidgesetz PY - 2026 AN - OPUS4-65507 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Appel, Paul Alexander A1 - Prinz, Carsten A1 - Low, Jian Liang A1 - Asres, Nahom Enkubahri A1 - Wu, Shu-Han A1 - Freytag, Annica A1 - Krug von Nidda, Jonas A1 - de Sousa Amadeu, Nader A1 - Fellinger, Tim-Patrick T1 - Kern–Schale: Versiegelung nanoporöser Partikel mit semipermeablen Kohlenstoffschichten befreit Hartkohlenstoffanoden von ihrem Dilemma N2 - In der vorliegenden Arbeit wird eine Kern-Schale-Strategie vorgestellt, die das grundlegende Problem gängiger nichtgraphitischer Hartkohlenstoff-Anoden adressiert: Hohe reversible Kapazitäten gehen bislang typischerweise mit erheblichen irreversiblen Verlusten in den ersten Zyklen einher. Analog zu Graphit, das sowohl Lithiumspeicherung als auch die Abtrennung von Elektrolytlösungsmitteln in einer homogenen Struktur vereint, zeigen wir, dass sich diese beiden Funktionen auch in nichtgraphitischen Kohlenstoffen gezielt in einer heterogenen Architektur kombinieren lassen. Hochporöse Aktivkohlen werden durch kinetisch kontrollierte Gasphasenabscheidung mit einer dünnen Schicht nichtgraphitischen Kohlenstoffs überzogen, sodass eine funktionale Kern-Schale-Struktur entsteht. Gasadsorptionsmessungen an Kern-, Schalen-, Kern-Schale- und mechanisch beschädigte Kern-Schale-Partikeln, bestätigen, dass die Porosität des Kerns erhalten bleibt und die Schale semipermeabel ist. Die Sorption von Diethylcarbonat wird als geeignetere Methode im Vergleich zu N2- oder CO2-Sorptionsmessungen eingeführt, um die irreversiblen Verluste des ersten Zyklus mit der tatsächlichen Flüssig-Fest-Grenzfläche von Kohlenstoffanoden zu verknüpfen. Die funktionalen Kern-Schale-Partikel zeigen eine stark reduzierte Aufnahme von Diethylcarbonat, was hohe reversible Kapazitäten bei deutlich geringeren Erstzyklusverlusten ermöglicht. Bei einer reversiblen Kapazität von 400 ± 24 mAh g−1 und einer initialen Coulombeffizienz von 82 ± 2% zeigt sich, dass die dreistufige Natriumspeicherung in der gezielt entwickelten Kern-Schale-Architektur den größeren Ionenradius von Natrium gegenüber Lithium (372 mAh g−1 in Graphit) kompensieren kann. Die entwickelten Kern-Schale-Anoden erreichen damit ein Leistungsniveau, das für eine kommerzielle Anwendung vielversprechend ist. KW - Kern-Schale-Struktur KW - Natriumionenbatterie KW - Hartkohlenstoffanode KW - Diethylcarbonatdampfsorption KW - Aktivkohle PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655354 DO - https://doi.org/10.1002/ange.202519457 SN - 1521-3757 N1 - Es gibt eine parallele Sprachausgabe (englisch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (English), a link is in the field related identifier SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-65535 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Appel, Paul Alexander A1 - Prinz, Carsten A1 - Low, Jian Liang A1 - Asres, Nahom Enkubahri A1 - Wu, Shu-Han A1 - Freytag, Annica A1 - Krug von Nidda, Jonas A1 - de Sousa Amadeu, Nader A1 - Fellinger, Tim-Patrick T1 - Core‐Shell: Resolving the Dilemma of Hard Carbon Anodes by Sealing Nanoporous Particles With Semi‐Permeable Coatings N2 - A core-shell strategy is introduced to overcome the dilemma of common non-graphitic hard carbon anodes, linking high reversible storage capacity to practically unacceptable irreversible losses in the first cycle(s). Just as Graphite homogeneously combines effective lithium storage with an electrolyte solvent-sieving function, we show that both of these functions could be strategically integrated into non-graphitic carbons in a heterogeneous structure. Highly porous activated carbons are sealed by kinetically tuned gas-phase deposition of non-graphitic carbon to form a functional core-shell structure. Gas sorption porosimetry on core, shell, core–shell, and cracked core-shell particles confirms preserved core porosity and a semi-permeable shell. Diethyl carbonate sorption analysis is introduced as a more suitable probe than N2 or CO2 sorption, linking first-cycle losses to the liquid–solid interface of carbon anodes. The functional core-shell particles with much reduced diethyl carbonate uptake allow for high storage capacity and reduced first cycle losses. Delivering 400 ± 24 mAh g−1 with 82 ± 2% first-cycle reversibility, it is shown that three-stage Na storage in designed core-shell anodes can compensate for the larger size of sodium compared to lithium stored in graphite anodes (372 mAh g−1). The designed core-shell anodes show state-of-the-art performance with commercial promise. KW - Sodium-ion battery KW - Activated carbon KW - Core-shell KW - Hard carbon anode KW - Diethyl carbonate vapor sorption PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655346 DO - https://doi.org/10.1002/anie.202519457 SN - 1433-7851 N1 - Es gibt eine parallele Sprachausgabe (deutsch), ein Link befindet sich im Feld zugehöriger Identifikator - There is a parallel language edition (German), a link is in the field related identifier SP - 1 EP - 9 PB - Wiley-VCH CY - Weinheim AN - OPUS4-65534 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tiebe, Carlo T1 - Advancing Traceability of Humidity Sensors for CO2-Based Applications Using Optical-Feedback Cavity-Enhanced Spectroscopy and Chilled Mirror Hygrometers N2 - Advancing Traceability of Humidity Sensors for CO₂-Based Applications Using Optical Feedback Cavity Enhanced Spectroscopy and Chilled Dew Point Hygrometers Content : The volume fraction of humidity in gaseous feedstocks, intermediates, products, and carrier gases plays a critical role in numerous industrial processes. Two emerging areas of application are particularly noteworthy. On the one hand, there is a strategic shift towards replacing fluorinated inert gases of gas-insulated switchgear systems, and on the other hand, cost-effective humidity measurements are gaining importance in the carbon capture and storage (CCUS) applications. The accuracy of applied sensor-based systems in these contexts must be assessed with respect to the specified threshold value of the application. However, the reliability and reproducibility of the reading have to be assessed to prevent errors. Generally, humidity measurement in gaseous carbon dioxide is feasible; however, the chemical reactivity of water with CO₂ can cause significant matrix effects. If the ITS-Sonntag equation is considered to be valid in carbon dioxide, chilled mirror hygrometers can be applied for reference measurements. Further, spectroscopic methods, like optical feedback cavity enhanced absorption spectroscopy (OFCEAS), can be applied, offering another robust reference method for determining humidity volume fractions. Here, we applied OFCEAS and a chilled mirror hygrometer for reference value determination. We verified the traceability of both instruments to our in-house gravimetric gas standards containing (100.69 ± 1.564) µmol/mol water in carbon dioxide. We further applied dynamic dilution with our in-house designed humidification unit to create sample gases that contained a volume fraction of (10 to 500) µmol/mol. In these gases, verified by OFCEAS and chilled mirror hygrometer, we conducted a measurement campaign to identify and characterize matrix effects on coulometric and capacitive sensors. T2 - Gas Analysis 2026 CY - Paris, France DA - 27.01.2026 KW - Hygrometry KW - Humidity Sensor KW - OF-CEAS KW - Chilled Mirror KW - Optical-Feedback Cavity-Enhanced Spectroscopy PY - 2026 AN - OPUS4-65541 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kulkarni, Kajol A1 - Kemmler, Samuel A1 - Schwartz, Anna A1 - Gedik, Gülçin A1 - Chen, Yanxiang A1 - Papageorgiou, Dimitrios A1 - Kavroulakis, Ioannis A1 - Iakymchuk, Roman T1 - Harvesting energy consumption on European HPC systems: Sharing Experience from the CEEC project N2 - Energy efficiency has emerged as a central challenge for modern high-performance computing (HPC) systems, where escalating computational demands and architectural complexity have led to significant energy footprints. This paper presents the collective experience of the EuroHPC JU Center of Excellence in Exascale CFD (CEEC) in measuring, analyzing, and optimizing energy consumption across major European HPC systems. We briefly review key methodologies and tools for energy measurement as well as define metrics for reporting results. Through case studies using representative CFD applications (waLBerla, FLEXI/GALÆXI, Neko, and NekRS), we evaluate energy-to-solution and time-to-solution on diverse architectures, including CPU- and GPU-based partitions of LUMI, MareNostrum5, MeluXina, and JUWELS Booster. Our results highlight the advantages of accelerators and mixed-precision techniques for reducing energy consumption while maintaining computational accuracy. Finally, we advocate the need to facilitate energy measurements on HPC systems in order to raise awareness, teach the community, and take actions toward more sustainable exascale computing. T2 - SCA/HPCAsiaWS 2026: SCA/HPCAsia 2026 Workshops: Supercomputing Asia and International Conference on High Performance Computing in Asia Pacific Region Workshops CY - Osaka , Japan DA - 26.01.2026 KW - Energy consumption KW - eEergy measurement KW - Energy-to-solution KW - Mixed-precision KW - HPC KW - CFD PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-654175 DO - https://doi.org/10.1145/3784828.3785161 SP - 40 EP - 49 PB - ACM CY - New York, NY, USA AN - OPUS4-65417 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schiaroli, Alice A1 - Camplese, Davide A1 - Scarponi, Giordano Emrys A1 - Eberwein, Robert A1 - Ustolin, Federico A1 - Cozzani, Valerio T1 - Modelling the behaviour of cryogenic liquid hydrogen tanks engulfed in fire N2 - The safe use of liquid hydrogen as a clean fuel requires a deep understanding of its behaviour in accident scenarios. Among other scenarios, the possible involvement of cryogenic liquid hydrogen tanks in engulfing fires is of particular concern, due to the potentially severe consequences. This study proposes a computational fluid dynamic model suitable to simulate the behaviour of liquid hydrogen tanks equipped with multi-layer insulation (MLI) engulfed in fire. An original approach has been developed to assess the progressive degradation of the performance of the thermal insulation, that is crucial in determining the tank pressurization and failure. The model is validated against full-scale experimental fire tests. The outcomes of the model reproduce the progressive pressurization and the opening time of the pressure relief valve within 2 % error. The results demonstrate the importance of accounting for the dynamic evolution of the progressive degradation of the insulation when evaluating tank pressurization, and they highlight the limitations of empirical, simplified state-of-the-art approaches. Furthermore, the analysis evidences the key role of the fire temperature in governing tank response, stressing the need for proper fire characterization to support reliable modelling of fire scenarios and the development of emergency planning and mitigation strategies ensuring the structural integrity of liquid hydrogen tanks during fire attacks. KW - LH2 KW - LNG KW - Fire KW - Tank PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652920 DO - https://doi.org/10.1016/j.psep.2025.108319 SN - 0957-5820 VL - 206 SP - 1 EP - 14 PB - Elsevier Ltd. AN - OPUS4-65292 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram T1 - Statistische Auswertung der SE(B)-Bruchzähigkeitsdatenbasis und Untersuchungen zum Bruchmechanismus - Neue Ergebnisse zur Untersuchung des Master Curve Konzepts für ferritisches Gusseisen mit Kugelgraphit bei dynamischer Beanspruchung (Projekt MCGUSS) N2 - Die Zielstellung des laufenden Kooperationsprojektes MCGUSS zwischen der BAM Berlin und der MPA Stuttgart ist es, das probabilistische Master Curve (MC)-Konzept hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI) zu untersuchen. Über Teilergebnisse der Arbeiten wurde bereits auf den Jahrestagungen 2023 bis 2025 des DVM-AK Bruchmechanik und Bauteilsicherheit berichtet. Der vorliegende Beitrag hat zwei Schwerpunkte. Zum einen wurde die Datenbasis der dynamischen Bruchzähigkeit für SE(B)-Proben der Dicken 10 mm, 25 mm und 140 mm auf insgesamt 101 Versuche bei Temperaturen von -40 °C bis -140 °C erweitert, statistisch ausgewertet sowie MC-Analysen unterzogen. Die Ergebnisse zeigen, dass die Daten sich zwar mit einer Weibullverteilung gut beschreiben lassen, die MC-Methode nach ASTM E1921 jedoch nicht ohne Weiteres anwendbar ist, sondern Modifikationen erforderlich sind. Des Weiteren werden neue Ergebnisse zum werkstoffspezifischen Bruchmechanismus bei dynamischer Belastung im unteren Übergangsbereich der Zähigkeit diskutiert. Die fraktographische Datenbank wurde durch REM-Analysen weiterer Bruchflächen von SE(B)25-Proben bei -40 °C, -60 °C und -80 °C ergänzt. Die Ergebnisse unterstreichen die prägende Rolle, die Rissarrestereignissen im Verlauf des dynamischen Sprödbruchversagens bei DCI zukommt. Der in MCGUSS zur Erklärung eines gegenüber Stahl inversen Probengrößeneinflusses vorgeschlagene Mechanismus „Specimen size-dependent arrest of local brittle fractures before global brittle failure by weakest link“ wird dadurch weiter unterstützt. T2 - DVM-Jahrestagung 2026 des Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Stuttgart, Germany DA - 24.02.2026 KW - Dynamic fracture toughness KW - Ductile cast iron KW - Safety assessment KW - Master curve KW - Statistics PY - 2026 AN - OPUS4-65593 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sander, Luise T1 - Linking material and electrode properties to the cell performance of commercially available sodium-ion cells N2 - As the first commercial sodium-ion-batteries (SIBs) are available for purchase, it is possible to investigate material composition. Gaining an insight into the material composition of these SIBs is of interest not only for the classification of possible safety risks and hazards, but also in regard to recycling. Herein we report the preliminary investigations of the chemical and structural composition of first commercial SIB-cells.[1,2] Two different SIB-cell types were compared in terms of electrode size, thickness, loading etc. Furthermore, the composition of the active materials and electrolyte was investigated and compared. Finally, the gained results were linked to the different data sheet performance of the two cell types. T2 - Batterieforum Deutschland 2026 CY - Berlin, Germany DA - 20.01.2026 KW - Electrochemical Energy Storage KW - Battery KW - Sodium-ion-battery KW - EES KW - Energy Storage PY - 2026 AN - OPUS4-65588 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, Diana A1 - Hahn, Oliver T1 - Colours on Maps - Purpose and Materiality N2 - Colours are an inseparable attribute of most maps. While colouring seems at first glance simply superficial ‘prettifying’ of maps, most maps were given colours for other reasons: colour is an important key to understanding the function and use of maps. The use of colours, the choice of where to assign them and the meaning given to them has accordingly never been static but has changed over time. In this context, the three aspects: colour system, colour scheme, and colour code are of particular importance. Material scientific analysis makes it possible to find out more about the material composition of colourants (pigments and dyes) on maps. The study of colourants provides insights into the production conditions and use of maps. Furthermore, it offers clues about colour changes and forms the basis for appropriate restoration concepts. T2 - Maps. Digital. Analogue CY - Oxford, United Kingdom of Great Britain and Northern Ireland DA - 26.02.2026 KW - Maps KW - Colours KW - Archaeometry KW - Aging PY - 2026 AN - OPUS4-65599 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Frechilla, A. A1 - Martínez, E. A1 - del Moral, J. A1 - López-Santos, C. A1 - Frechilla, J. A1 - Nuñez-Gálvez, F. A1 - López-Flores, V. A1 - de la Fuente, G.F. A1 - Hülagü, Deniz A1 - Bonse, Jörn A1 - González-Elipe, A.R. A1 - Borrás, A. A1 - Angurel, L.A. T1 - Influence of near-edge Laser-Induced Periodic Surface Structures (LIPSS) on the electrical properties of fs-laser-machined ITO microcircuits N2 - Scalable, cost-effective methods for processing transparent electrodes at the microscale are pivotal to advancing in electrochemistry, optoelectronics, microfluidics, and energy harvesting. In these fields, the precise fabrication of micrometric circuits and patterns plays a critical role in determining device performance, material compatibility, and integration with added-value substrates. In this context, Laser Subtractive Manufacturing stands out as a suitable microfabrication technique for its adaptability to diverse materials and complex configurations, as well as its straightforward scalability, affordability, and eco-friendly nature. However, a challenge in micromachining metals and metal oxides is the inherent formation of Laser-Induced Periodic Surface Structures (LIPSS), which can significantly impair electrical conductivity, particularly when circuit dimensions fall within the micrometer range. Herein, we investigate the micromachining of electrical microcircuits using ultrashort pulse laser systems applied to transparent indium tin oxide (ITO) thin films. We analyze the formation of LIPSS at the edges of the micromachined regions associated with the Gaussian distribution of the energy within the laser spot, and the impact of these structures on the electrical properties of the circuits. Thus, we systematically evaluate the influence of LIPSS orientation and periodicity by fabricating various circuit patterns using femtosecond lasers at green (515 nm) and ultraviolet (UV) (343 nm) wavelengths. A correlation between electrical resistivity measurements and microstructure analysis, as determined by field emission scanning electron and transmission electron microscopy, reveals distinct effects of the formed nanostructures depending on the laser source and its polarization. For the green wavelength, the edge side regions where LIPSS are oriented perpendicular to the ITO track exhibit a resistance higher by a factor just above two compared to those where LIPSS are parallel. Additionally, UV laser processing results in a pronounced reduction of ITO thickness at the boundary between the LIPSS region and the substrate. The mechanisms for the formation of LIPSS with both wavelengths are also discussed. Furthermore, we have determined that in narrow conductive tracks with a width ranging from 6 to 8 µm, the impact of LIPSS is particularly significant because the LIPSS structured region occupies a dominant fraction of the total width. KW - ITO KW - Laser-induced periodic surface structures (LIPSS) KW - Laser subtractive manufacturing KW - fs-laser processing KW - Electrical properties PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655921 DO - https://doi.org/10.1016/j.apsusc.2026.166415 SN - 0169-4332 VL - 731 SP - 1 EP - 13 PB - Elsevier B.V. AN - OPUS4-65592 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Baer, Wolfram A1 - Ohm, Katrin A1 - Holzwarth, Marcel T1 - Statistische Auswertung der SE(B)-Bruchzähigkeitsdatenbasis und Untersuchungen zum Bruchmechanismus – neue Ergebnisse zur Untersuchung des Master Curve Konzepts für ferritisches Gusseisen mit Kugelgraphit bei dynamischer Beanspruchung (Projekt MCGUSS) N2 - Die Zielstellung des laufenden Kooperationsprojektes MCGUSS zwischen der BAM Berlin und der MPA Stuttgart ist es, das probabilistische Master Curve (MC)-Konzept hinsichtlich seiner Übertragbarkeit auf ferritisches Gusseisen mit Kugelgraphit (DCI) zu untersuchen. Über Teilergebnisse der Arbeiten wurde bereits auf den Jahrestagungen 2023 bis 2025 des DVM-AK Bruchmechanik und Bauteilsicherheit berichtet. Der vorliegende Beitrag hat zwei Schwerpunkte. Zum einen wurde die Datenbasis der dynamischen Bruchzähigkeit für SE(B)-Proben der Dicken 10 mm, 25 mm und 140 mm auf insgesamt 101 Versuche bei Temperaturen von -40 °C bis -140 °C erweitert, statistisch ausgewertet sowie MC-Analysen unterzogen. Die Ergebnisse zeigen, dass die Daten sich zwar mit einer Weibullverteilung gut beschreiben lassen, die MC-Methode nach ASTM E1921 jedoch nicht ohne Weiteres anwendbar ist, sondern Modifikationen erforderlich sind. Des Weiteren werden neue Ergebnisse zum werkstoffspezifischen Bruchmechanismus bei dynamischer Belastung im unteren Übergangsbereich der Zähigkeit diskutiert. Die fraktographische Datenbank wurde durch REM-Analysen weiterer Bruchflächen von SE(B)25-Proben bei -40 °C, -60 °C und -80 °C ergänzt. Die Ergebnisse unterstreichen die prägende Rolle, die Rissarrestereignissen im Verlauf des dynamischen Sprödbruchversagens bei DCI zukommt. Der in MCGUSS zur Erklärung eines gegenüber Stahl inversen Probengrößeneinflusses vorgeschlagene Mechanismus „Specimen size-dependent arrest of local brittle fractures before global brittle failure by weakest link“ wird dadurch weiter unterstützt. T2 - DVM-Jahrestagung 2026 des Arbeitskreises Bruchmechanik und Bauteilsicherheit CY - Stuttgart, Germany DA - 24.02.2026 KW - Statistics KW - Dynamic fracture toughness KW - Ductile cast iron KW - Master curve KW - Safety assessment PY - 2026 SP - 1 EP - 12 PB - DVM-Verlag CY - Berlin AN - OPUS4-65591 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Askar, Enis T1 - Safety in Energy Gases "Explosion Protection" N2 - The legal framework and standards for explosion protection are presented briefly and than the three basic principles of explosion protection are shown one by one: Avoiding Explosive Mixtures, Avoiding Ignition Sources and Mitigation of Consequences. For each of these the relevant safety characteristics and methods of implementation are shown. Finally references for Safety characteristic data and literature sources are shown and the safety characteristics of different fuel gases are summarized and compared. T2 - European Metrology Network for Energy Gases Training Session CY - Online meeting DA - 25.02.2026 KW - Safety characteristics KW - Energy carrier KW - Ignition KW - Safety PY - 2026 AN - OPUS4-65582 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chakraborty, Gouri A1 - Das, Prasenjit A1 - Bhattacharya, Biswajit A1 - Prinz, Carsten A1 - Emmerling, Franziska A1 - Thomas, Arne T1 - Room-temperature superprotonic conductivity in COOH-functionalized multicomponent covalent organic frameworks N2 - In solid materials, the development of hydrogen bonding (H-bonding) networks within pores is crucial for efficient proton conductance. In this study, a chemically stable carboxylic acid-functionalized, quinoline-linked 2D microporous covalent organic framework (COF) (Qy-COOH) was synthesized using the Doebner multicomponent reaction (MCR) and compared to a similar framework lacking the –COOH functionality (Qy-H), prepared via an MC Domino reaction. The proton conductivity of the –COOH-functionalized MCR-COF was significantly enhanced, reaching 10−2 S cm−1, attributed to strong H-bonding interactions between water molecules and the dangling –COOH groups within the COF pores. In contrast, the analogous Qy-H framework exhibited a much lower proton conductivity of 10−5 S cm−1, while an imine-based COF showed only 10−6 S cm−1. This work represents the first demonstration of a general strategy to achieve efficient proton conduction in a class of layered 2D –COOH-functionalized COFs, offering superprotonic conductivity without requiring additives at room temperature. The MCR-COF design approach provides a promising pathway for developing highly stable and high-performance proton-conducting materials. KW - Multicomponebt KW - COF KW - Proton Conductivity KW - Superprotonic PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-653526 DO - https://doi.org/10.1039/D5SC06953J SN - 2041-6520 SP - 1 EP - 9 PB - Royal Society of Chemistry (RSC) AN - OPUS4-65352 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sauer, Hannah A1 - Okpeke, Bright E. A1 - Dzielendziak, Agnieszka S. A1 - Eberwein, Robert A1 - Baetcke, Lars A1 - Ehlers, Sören T1 - Comparative life cycle assessment of vacuum insulation panel core materials for liquid hydrogen storage tanks – glass bubbles compared to conventional core materials N2 - The environmental performance of insulation materials for liquid hydrogen storage tank application is important to the development of sustainable supply chains. As new materials keep evolving, there is a need to assess their environmental impact. Therefore, this study investigates the environmental sustainability and circularity of cryogenic insulation concepts, namely vacuum insulation panels (VIPs), exclusively focussing on their core materials. Employing a cradle-to-grave life cycle assessment model, the VIP core materials are investigated with a special focus on glass bubbles. Based on the results, the global warming potential of the considered core materials, namely, glass bubbles, silica aerogel, fumed silica, expanded perlite, glass fibre, and polyurethane foam is 9.21∗10^−2, 7.00, 2.50∗10^−1, 3.63∗10^−2, 6.68∗10^−2, and 1.88 kg CO2 eq. per functional unit, respectively. In general, silica aerogel and polyurethane foam are the least environmentally friendly materials, while the most sustainable is expanded perlite, followed by glass fibre, glass bubbles, and fumed silica. KW - LH2 KW - Insulation KW - Cryogenic storage tank KW - Life Cycle Assessment PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655445 DO - https://doi.org/10.1016/j.ijhydene.2026.153937 SN - 0360-3199 VL - 219 SP - 1 EP - 11 PB - Elsevier Ltd. AN - OPUS4-65544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chaudhuri, Somsubhro A1 - Krankenhagen, Rainer A1 - Lapšanská, Ivana A1 - Stamm, Michael T1 - Modeling Temperature Responses of a Wind Turbine Blade Section Under Climate Chamber Conditions – Part 1: Challenges for FEM Simulations N2 - The rapid expansion of wind energy infrastructure over the past 20–30 years has led up to a situation where advanced non‐destructive testing (NDT) technologies are the need‐of‐the‐hour, not only for new wind turbine blades (WTBs) that are being installed, but also for older infrastructure which is reaching their designed lifetime. NDT technologies that improve both the quality as well as reduce the time required for the inspection are sought after, and one such example is passive infrared thermography (IRT). For passive IRT to provide significant information/insight into the integrity of the WTB, there needs to exist certain thermal contrast to both visualize and distinguish between features in WTB. These features could be surface features, subsurface structure or defects. The temperature variations due to air temperature fluctuations and the sun assist (passively) to obtain the necessary thermal contrast. To better understand the thermal response of composite structures such as WTBs, a validation study was conducted using a WTB section subjected to controlled temperature transients within a climate chamber, without external irradiation. Infrared measurements were recorded using a thermographic camera, and the same specimen was modeled using finite element methods (FEM) in COMSOL Multiphysics. While a direct validation of the simulation is limited due to transient and unmeasured variables in the experimental data, qualitative comparison provides valuable insight into the applicability of FEM for predicting thermal behavior in passive IRT scenarios. This article represents the first part of a two‐part study, focusing on the FEM modeling approach and associated challenges. The second part will address the experimental investigation in more detail, with an emphasis on thermal contrast behavior under varied transient conditions. KW - Finite element modeling KW - Non- destructive testing KW - Passive infrared thermography KW - Thermal contrast KW - Wind turbine blades PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655330 DO - https://doi.org/10.1002/we.70102 SN - 1095-4244 VL - 29 IS - 3 SP - 1 EP - 14 PB - Wiley AN - OPUS4-65533 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Czeskleba, Denis A1 - Rhode, Michael A1 - Wandtke, Karsten A1 - Irfan, Muhammad Dary A1 - Kannengiesser, Thomas T1 - Hydrogen diffusion in thick-walled S690 saw joints: part 1—experimental determination of microstructure-dependent diffusion coefficients N2 - High-strength low-alloyed steel S690 is widely used in heavy-duty applications, such as structural components, mobile cranes, and industrial plant construction, owing to their high strength and weldability. However, thick-plate submerged arc welding (SAW) can introduce elevated hydrogen levels and residual stresses that promote time-delayed hydrogen-assisted cold cracking (HACC). Accurate, microstructure-specific diffusion data are scarce, limiting predictive HACC assessments. This study presents an experimental determination of hydrogen diffusion coefficients (DH) in two S690 variants: thermomechanically rolled (S690MC) and quenched and tempered (S690Q). Multi-layer SAW welds were produced from 30 mm thick plate material at three heat input levels, and diffusion membranes were extracted from weld metal (WM), heat-affected zone (HAZ), and base material (BM). Hydrogen permeation tests, conducted in accordance with DIN En ISO 17081, yielded flux curves normalized in time from which DH was derived using the inflection-point method. At room temperature, DH values ranged from 6 × 10−5 mm2/s to 9 × 10−5 mm2/s across all regions and heat inputs, with no significant difference between S690MC and S690Q. Weld metal exhibited marginally lower DH, attributed to enhanced hydrogen trapping, while base material measurements showed greater variability. These microstructure-resolved diffusion coefficients add quantitative data for modern S690 SAW welds and provide internally consistent input parameters for the numerical simulations presented in part 2. The results support improved parameterization for subsequent assessments of HACC risk through the optimization of welding parameters. KW - Hydrogen assisted cracking KW - Submerged arc welding KW - Diffusion KW - Electrochemical permeation KW - Microstructure PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655711 DO - https://doi.org/10.1007/s40194-026-02400-7 SN - 0043-2288 SP - 1 EP - 15 PB - Springer Science and Business Media LLC AN - OPUS4-65571 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Czeskleba, Denis A1 - Rhode, Michael A1 - Wandtke, Karsten A1 - Irfan, Muhammad Dary A1 - Kannengiesser, Thomas T1 - Hydrogen diffusion in thick-walled S690 SAW joints: part 2 – predictive modeling of heat input and microstructure influence N2 - High-strength low-alloy (HSLA) steels such as S690 are widely employed in thick-walled welded structures, where hydrogen-assisted cold cracking (HACC) remains a persistent concern. While microstructure-specific hydrogen diffusion coefficients (DH) for weld metal (WM), heat-affected zone (HAZ), and base material (BM) were experimentally established in Part 1 of this study, their quantitative influence on hydrogen accumulation and effusion has not yet been fully clarified. This work presents a transient, spatially resolved numerical model for simulating hydrogen transport in multi-pass submerged arc welds. The model integrates experimentally determined DH values with realistic thermal cycles and temperature-dependent boundary conditions. Developed in Python, the simulation tool is purpose-built for hydrogen diffusion in welded joints. It offers a focused, transparent alternative. It offers a focused, transparent alternative to general-purpose finite element platforms. Parametric analyses demonstrate that, although the diffusion coefficients vary by up to 50%, their impact on overall hydrogen retention is minor. In contrast, plate thickness, bead geometry, cooling time (t₈/₅), and interpass temperature exert a dominant influence on hydrogen distribution. Despite clear microstructural differences between the thermomechanically rolled (S690MC) and quenched and tempered (S690Q) variants, including opposite HAZ hardness responses (softening in S690MC, hardening in S690Q) in the (pen)ultimate weld bead, the simulations confirm that their diffusion behavior and hydrogen solubility are closely aligned. Consequently, differences in DH and solubility exert only a minor influence on hydrogen retention compared to thermal exposure and joint geometry. These findings support the interchangeable use of both steel grades in terms of HACC risk due to hydrogen diffusion kinetics under comparable welding conditions. KW - Hydrogen assisted cracking KW - Numerical simulation KW - Diffusion KW - Submerged arc welding PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-655721 DO - https://doi.org/10.1007/s40194-026-02395-1 SN - 0043-2288 SP - 1 EP - 16 PB - Springer Science and Business Media LLC AN - OPUS4-65572 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hahn, Sarah-K. T1 - Second Life Batterien - Alterungsverhalten und Brandversuche N2 - Der Vortrag gibt zunächst einen Themeneinstieg in den Bereich der Second-Life-Batterien sowie rechtliche und technische Grundlagen zu Lebenszyklus und Alterung. Im Weiteren werden experimentelle Ergebnisse aus Versuchen zum thermischen Durchgehen mit Batteriemodulen aus dem BMBF-Vorhaben SEE-2L vorgestellt. Darüber hinaus wird ein eigens entwickelter Ausbildungsdemonstrators vorgestellt, welcher einen wesentlichen Baustein des Ergebnistransfers aus dem Vorhaben darstellt. T2 - 19. Fachkonferenz Lithiumbatterien CY - Göttingen, Germany DA - 26.01.2026 KW - Auswirkungsbetrachtungen KW - Elektrische Energiespeicher KW - Lithium-Ionen-Batterie KW - Second Life KW - Thermisches Durchgehen PY - 2026 AN - OPUS4-65621 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bayat, Mehmet Emin T1 - Traceable dynamic and gravimetric preparation of trace ammonia in hydrogen gas standards for ISO 14687 N2 - Trace ammonia impurities in hydrogen fuel poison proton-exchange-membrane fuel cells (PEMFC), causing irreversible performance degradation. Accurate quantification of ammonia in so-called Grade D hydrogen fuel is crucial for ensuring PEMFCs long-term operational stability and performance. According to ISO 14687 grade D hydrogen fuel sets a stringent threshold value of just 100 nmol/mol for ammonia impurities. Given the potential of an ammonia-based hydrogen supply chain, reliable quantification of ammonia contamination appears even more relevant. Hydrogen quality assessments for ammonia impurities typically employ techniques such as gas chromatography, cavity-enhanced absorption spectroscopy, or mass spectrometry. These techniques, however, require stable reference gases for calibration and long-term method validation. Typically, gravimetrically produced reference gases are used. However, ammonia poses unique challenges due to its chemical reactivity and stickiness. By applying (ultra )long-path Optical Feedback Cavity Enhanced Absorption Spectroscopy we observed that above a certain amount of ammonia, the gravimetric amount deviates from the analytically determined amount. This discrepancy most likely arises due to strong adsorption of ammonia onto the inner surface of the gas cylinder. Therefore, we investigated the lowest gravimetrically preparable amount of ammonia in hydrogen for which the analytically measured amount of the cylinder remains congruent with the gravimetric amount of substance. We further investigated the applicability of passivated cylinders for trace ammonia gas standards and compared their performance to aluminum alloy cylinders. To confirm reproducibility of our results, we conducted three independent gravimetric preparation campaigns, each employing optimizations, or changes in methodology, at different times. Finally, we investigated whether those gravimetrically prepared trace amounts of ammonia in hydrogen gas standards were long-term-stable. Beyond gravimetrically prepared gas standards, we evaluated how a cutting-edge dynamic dilution system could reliably extend trace-ammonia calibration down to the ISO limit of 100 nmol/mol. For this purpose, we developed an advanced dynamic dilution system capable of a one-in-a-billion dilution ratio, validated for its SI traceability, reproducibility, and operational limits by applying an internal standard. In summary, our results demonstrate that precise dynamic dilution, coupled with concentrated gravimetrically prepared ammonia gas mixture, provides a route to full SI-traceable trace-ammonia reference sample gases. T2 - Gas Analysis Symposium 2026 CY - Paris, France DA - 27.01.2026 KW - Ammonia KW - Hydrogen KW - Gravimetric preparation KW - OF-CEAS KW - ISO 14687 PY - 2026 AN - OPUS4-65620 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gleim, Tobias T1 - Großbrandversuche von Elektrofahrzeugen zum Transport Gefährlicher Güter N2 - Der zunehmende Einsatz von batterieelektrischen Transportfahrzeugen (Battery Electric Transport Vehicles – BETVs) im Verkehrswesen wirft Sicherheitsfragen beim Transport gefährlicher Güter auf. Obwohl Batteriebrände auf Zell-, Modul- und Fahrzeugebene umfassend untersucht wurden, fehlen systematische Daten zu deren thermischen Auswirkungen auf Gefahrgutverpackungen. Um diese Lücke zu schließen, führt die Bundesanstalt für Materialforschung und -prüfung (BAM) auf ihrem Testgelände Technische Sicherheit (BAM-TTS) groß angelegte Brandtests durch, in denen konservative Unfallszenarien mit unterschiedlichen Zellchemien und -kapazitäten nachgestellt werden. Die Tests kombinieren fahrzeugbedingte Brandlasten mit standardisierten Propan-Referenzbränden und erfassen mittels hochauflösender Instrumente zentrale Messgrößen wie Wärmefluss, Temperatur und Strahlung. Der daraus entstehende Datensatz liefert erstmals eine direkte Quantifizierung der thermischen Auswirkungen von BETV-Bränden auf Verpackungen und unterstützt Expertengremien bei der Bewertung, ob bestehende regulatorische Anforderungen für alternative Antriebssysteme weiterhin angemessen sind. T2 - Informationsaustausch zur verkehrsrechtlichen Aufsicht bei der Beförderung radioaktiver Stoffe CY - Salzgitter, Germany DA - 03.02.2026 KW - Batteriebrand KW - IAEA KW - Gefahrgut KW - Transport PY - 2026 AN - OPUS4-65626 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Wu, Shu-Han T1 - MOF-derived Synthetic Carbon Anode Materials for Sodium-Ion Batteries N2 - Metal-organic frameworks (MOFs), particularly the zeolitic imidazolate framework (ZIF) family, are attractive precursors for advanced energy-storage materials. Upon pyrolysis, ZIFs can be transformed into electrically conductive carbon materials while preserving their original particle morphology, which is crucial for achieving high-performance sodium-ion battery anodes. Despite these advantages, large-scale implementation remains challenging due to the need for synthesis routes that balance performance, cost, and sustainability. The present study addresses these challenges by developing environmentally benign and economically feasible strategies for the scalable production of ZIF-8-derived carbon anodes suitable for industrial applications. T2 - Batterieforum Deutschland 2026 CY - Berlin, Germany DA - 20.01.2026 KW - Sodium-ion battery KW - Negative electrode KW - Metalorganic frameworks PY - 2026 AN - OPUS4-65644 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Aliyah, K. A1 - Berger, A. A1 - Lazaridis, T. A1 - Appel, C. A1 - Prehal, C. A1 - Menzel, A. A1 - Guizar-Sicairos, M. A1 - Smales, Glen J. A1 - Pauw, Brian Richard A1 - Gasteiger, H. A. A1 - Gubler, L. A1 - Büchi, F. N. A1 - Eller, J. T1 - Impact of Microporous Layer Composition on the Water Content in the Membrane Electrode Assembly of Polymer Electrolyte Fuel Cells N2 - Polymer electrolyte fuel cells are paramount for future emission-free mobility. One of the vital challenges for prospering commercialization of PEFCs is water management in the cells. A microporous layer (MPL) is typically positioned between the gas Diffusion layer (GDL) and the catalyst layer (CL) to boost the cell performance and facilitate water management. In this study, three different MPLs were investigated, namely, carbon black-based MPLs with different PTFE binder contents (20 wt % PTFE as a base case and 40 wt % PTFE), as well as perforated MPLs with micron-sized pores coated on the same GDL- Substrate (Freudenberg H14). The water content in the membrane, catalyst layers (CL), and MPLs was explored using operando scanning small- and wide-angle X-ray scattering (S/WAXS). At Tcell = 80 °C, relative humidity = 100%, pabs = 3 bar, the MPL with larger pores exhibits slightly higher performance than the base case, while a considerably lower cathode CL and MPL saturation levels were observed for the MPL. In contrast, the MPL with higher amounts of PTFE binder shows lower performance than the base case, with considerably higher cathode CL and MPL saturation levels. 3D representations of how the pores could be filled in the cathode CLs were obtained from operando SAXS profiles using representative structure modeling for the different materials and operating conditions. KW - Polymer electrolyte fuel cell KW - Catalyst layer saturation KW - Microporous layer saturation KW - Membrane hydration KW - Small and wide-angle scattering KW - MOUSE KW - SAXS KW - X-ray scattering KW - Energy storage materials PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656691 DO - https://doi.org/10.1021/acsami.5c22540 SN - 1944-8244 SP - 1 EP - 17 PB - American Chemical Society (ACS) AN - OPUS4-65669 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Berger, J. A1 - Zahedi-Azad, S. A1 - Voss, H. A1 - Ernst, O.C. A1 - Hammerschmidt, R. A1 - Boeck, T. A1 - Martin, J. A1 - Bonse, J. A1 - Krüger, J. A1 - Schmid, M. T1 - CuInSe2-based micro-concentrator solar cells fabricated from In islands grown by laser-assisted MO-CVD N2 - Micro-concentrator solar cells offer a promising route for reducing material usage in photovoltaics. For Cu(In,Ga)Se2, multiple micro-concentrator manufacturing methods have already been evaluated. All of them involve either high preparation complexity or post-processing to recycle unused precursor or absorber materials. In this work, a new method using laser-assisted metal-organic chemical vapor deposition (LA-MOCVD) was applied to directly grow arrays of indium micro-islands. These arrays are examined and further processed to CuInSe2 micro-solar cell arrays. The geometry and morphology of the islands were investigated and compared before and after absorber formation. The investigation shows that the absorber growth is limited to the vertical direction normal to the substrate surface and that the starting morphology is preserved. Furthermore, the absorber island arrays are processed into micro-modules and operational solar cells are achieved as a proof of principle. These not yet optimized arrays reach a conversion efficiency of 0.65% under 1 sun illumination. Under 17 suns of light concentration, the efficiency gain is between 60 and 250%. This work demonstrates the method's viability for the fabrication of micro-solar cell arrays, with clear potential for achieving higher conversion efficiencies through future optimization. KW - Micro-concentrator solar cells KW - Laser-assisted chemical vapor deposition KW - CISe KW - Bottom-up fabrication KW - Resource efficiency PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656711 DO - https://doi.org/10.1016/j.solmat.2026.114284 SN - 0927-0248 VL - 301 SP - 1 EP - 10 PB - Elsevier B.V. AN - OPUS4-65671 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Ekici, Nilsah A1 - Sobol, Oded T1 - SHIMMER Database for Hydrogen Integration in European Gas Grids N2 - The integration of hydrogen into existing natural gas infrastructure is an important pathway for achieving the European Union’s climate neutrality goals. However, hydrogen blending in gas networks raises technical challenges related to material compatibility, operational safety, and the lack of harmonized assessment methodologies across Europe. These challenges are addressed within the Safe Hydrogen Injection Modelling and Management for European Gas Network Resilience (SHIMMER) project, funded by the Clean Hydrogen Partnership under the Horizon Europe programme. A key outcome of the project is the development of an openly accessible database designed to support the assessment of hydrogen readiness in European gas networks and to facilitate knowledge sharing. The database compiles infrastructure data provided by project partners, including several European transmission and distribution system operators. It contains detailed information on gas network components such as pipelines, valves, fittings, gaskets, and compressors. In addition, a new category has been introduced focusing on the hydrogen compatibility of gas grid components and materials. This section provides structured information linking infrastructure components with material types and their hydrogen compatibility, enabling more systematic evaluation of hydrogen injection scenarios. By organizing heterogeneous datasets into a harmonized and user-friendly structure, the SHIMMER database supports research, best-practice development, and the safe integration of hydrogen into existing European gas infrastructure. T2 - EHEC 2026 CY - Seville, Spain DA - 11.03.2026 KW - Database KW - Gas Grid KW - Hydrogen KW - Low-carbon KW - Pipeline Steel PY - 2026 AN - OPUS4-65683 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Averin, Anton A1 - Hirsch, Philipp Daniel A1 - Lecompagnon, Julien T1 - Thermographic Reference Dataset: Defect Detection in Nuclear Waste Barrel Cutouts Using Long Pulse Thermography N2 - We introduce a thermographic dataset for subsurface defect detection in radioactive waste storage drums, comprising thermal sequences from 7 barrel specimens with artificially manufactured internal defects. The dataset was acquired using cost-effective halogen-lamp excitation (2kW per lamp) as an alternative to laser-based systems, with dual-camera thermal imaging (CMOS and bolometric) to enable performance comparison across imaging modalities. The specimens include both new and aged barrel types with controlled defects — FBHs, lines, crosses, triangles, and rectangles — simulating internal corrosion at varying scales (4mm to 60mm). Three heating regimes (both lamps, left only, right only) were systematically applied across multiple measurement regions per sample, yielding normalized thermal sequences. To lower the barrier for machine learning practitioners without thermography expertise, the dataset provides pre-computed features derived from principal component analysis, pulse phase thermography, and independent component analysis extracted using experimentally optimized time windows. Ground-truth binary masks mapping defect locations are included to enable supervised learning. This resource is designed to support the development and benchmarking of automated defect detection algorithms for non-destructive testing of curved, thin-walled metallic structures under realistic surface conditions (paint inhomogeneity, dirt, geometric artifacts), while validating low-cost thermographic inspection alternatives for industrial deployment. KW - Nondestructive Testing KW - Corrosion detection KW - Waste storage KW - Thermography KW - Safety PY - 2026 DO - https://doi.org/10.5281/zenodo.18916290 PB - Zenodo CY - Geneva AN - OPUS4-65666 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Engelking, Lorenz A1 - Eissel, A. A1 - Madia, Mauro A1 - Schröpfer, Dirk A1 - Treutler, K. A1 - Kruse, Julius A1 - Kannengießer, Thomas A1 - Wesling, V. T1 - Influence of ultrasonic-assisted milling on surface integrity of additively manufactured components using MSG processes N2 - Additive manufacturing (AM) is increasingly used for producing complex metallic components. Subsequent machining is essential to achieve final geometries and surface conditions. The resulting surface integrity, particularly the near-surface residual stress state, plays a crucial role in component performance and fatigue life. This study investigates the potential of ultrasonic-assisted milling (USAM), a hybrid machining process, to improve surface integrity and machinability compared to conventional milling (CM). Three materials were investigated, two difficult-to-cut materials CoCr26Ni9Mo5W and FeNi36 and a low-alloy steel S355J2C. The CoCr26Ni9Mo5W and FeNi36 were additively manufactured via Directed Energy Deposition (DED)-Arc and then machined with varying cutting speeds and feed rates within a Design of Experiments. USAM exhibited enhanced machinability and surface integrity, particularly at low cutting speeds, by reducing cutting forces up to 40% and shifting near-surface residual stresses from tensile to compressive. For S355J2C, USAM reduced cutting forces by approximately 45% and induced near-surface compressive residual stresses up to approximately −700 MPa. Rotating bending tests (DIN50100) show that USAM increases the technical fatigue limit from 307 MPa (CM) to 341 MPa (USAM), i.e., by ∼11%. These findings highlight the advantages of ultrasonic assistance in post-AM machining, offering enhanced fatigue performance and surface quality for various metallic materials. T2 - 4th International Conference on Advanced Joining Processes 2025 CY - Coimbra, Portugal DA - 16.10.2025 KW - Ultrasonic-assisted milling KW - Residual stress KW - Surface integrity PY - 2026 DO - https://doi.org/10.1177/14644207261416395 SP - 1 EP - 12 PB - Sage Journals AN - OPUS4-65682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Scharf-Wildenhain, R. A1 - Engelking, Lorenz A1 - Hälsig, A. A1 - Schröpfer, Dirk A1 - Kannengießer, Thomas A1 - Hensel, J. T1 - Influence of build‑up height on residual stresses in additive repair and modification using DED‑Arc with high‑strength filler metals N2 - Directed energy deposition (DED)-Arc is suitable for the hybrid additive manufacturing, modification and repair of large metal components with high deposition rates. Residual stresses and distortion are of central importance when characterizing the manufactured components and the sensitive transition area between additive manufactured (AM) component and semifinished product. Residual stresses caused by the thermal cycles during the manufacturing process can impair the mechanical properties of the manufactured parts and can lead to component failure, especially for high-strength steels. Therefore, understanding and controlling residual stresses, when combining different base and feedstock materials, is critical to improve the quality and efficiency of the hybrid DED-Arc process. This article deals with the influence of the build-up height on the residual stress distribution of additively manufactured components with a selected base and feedstock material from commercial high-strength steels. Using a robot-assisted DED-system and a controlled short arc, AM welding experiments were carried out with close to the application parameters at working temperature (200 °C) and heat input (650 kJ/m). Five hybrid AM specimens (AM wall on upright structural steel plate) were produced using a one bead per layer strategy and selected AM-wall heights between 15 and 300 mm. The influence of the AM build height on the longitudinal residual stress in the whole hybrid AM specimen (in welding direction) was analyzed and discussed. All experiments exhibit comparable stress distributions in the area of the substrate plate up to the heat-affected zone (HAZ) and the transition zone, regardless of the building height. The height significantly influences the residual stress distribution of the deposited AM-component. Tensile residual stresses with a maximum range between 300and 400 MPa were always found in the last approx. 18 component layers (upper 40 mm). This is due to restraint of the shrinking of the top layers by the layers below. The lower layers show homogeneous residual stress distributions characterized by low compressive stresses due to the process-related tempering during the deposition of each layer on top of each other. As a result, the significant difference between the various AM build-up heights of the hybrid AM specimens is the extent (or height) of this tempered zone with low compressive stresses. These correlations contribute to the understanding of residual stress development with increasing structure height or ratio of component heights of substrate semi-finished product and AM component in hybrid additive manufacturing. T2 - 78th IIW Annual Assembly and International Conference CY - Genoa, Italy DA - 22.06.2025 KW - DED-Arc KW - Residual stress KW - Heat control PY - 2026 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-656793 DO - https://doi.org/10.1007/s40194-026-02417-y SN - 1878-6669 SP - 1 EP - 12 PB - Spriner AN - OPUS4-65679 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -