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Platform MaterialDigital (PMD) - Knowledge Representation, Interoperability, Reliability
No full textThrough collaboration in the materials science and engineering (MSE) community, the PMD is collectively developing common standards and prototype solutions for data acquisition, structuring, storage, and processing. This comprises the development of architectural, standardized and foundational ontologies and workflows. Demonstrators resulting from these developments provide good practice examples. The PMD Core Ontology (PMDco) was created as an anchor that allows implementation of semantic data integration. It provides a common and expanding vocabulary to represent and share knowledge while enabling efficient collaboration and promoting interoperability between diverse domains
The KI-VISIR Reference Dataset: A Compilation of Thermal and Visual Inspection Data for Quantifying Leading Edge Rain Erosion
No full textThis presentation introduces thermography (thermal imaging) as a key method for non-destructive testing (NDT) of wind turbine rotor blades. By leveraging solar heating and aerodynamic effects, passive thermography detects internal defects, delaminations, and surface issues like leading edge erosion. We discuss field measurements, the role of AI/Machine Learning (LATODA) for automated defect classification, and its importance for improving O&M efficiency and lifetime extension in the wind energy sector
Experimental and reaction kinetic study of hydrogen ignition behavior at ignition limits
No full textThe paper presents the results of an experimental and reaction kinetic investigation of hydrogen ignition at different pressures in a closed vessel, highlighting its non-linear behavior and the effects of radical wall termination. The reaction kinetic simulation predicts the three characteristic ignition limits of hydrogen caused by radical and thermal auto-ignition and is in close agreement with the experimental measurements. The first ignition limit is determined by the chain branching reaction H+O_2→O+ OH. This limit shows strong sensitivity towards the wall termination of O, H and OH radicals. The second ignition limit is influenced by the wall termination of O, H, OH, HO2 and H2O2 radicals. The third ignition limit is dominated by the reaction paths HO_2+HO_2→H_2 O_2+O_2 and H_2 O_2+M→2 OH+M, which is why it shows strong sensitivity towards wall termination of HO₂ and H₂O₂ radicals. Increasing the radical wall termination rate by increasing the sticking coefficient of the radicals at the wall or the surface-to-volume-ratio leads to an increase of the auto-ignition temperature at the same pressure. The introduction of radical wall termination reactions improved the prediction of ignition limits and highlighted the profound effect of the autoclave wall and vessel size on the hydrogen ignition behavior
Tintencharakterisierung: Optische Eigenschaften und elementare Zusammensetzung
No full textDie Präsentation beschreibt alle Typen der schwarzen Schreibmaterialien, die in der Antike und Mittelalter benutzt wurden. Weiterhin wir das bei der BAM entwickelte Untersuchungsprotokoll präsentiert, das aus zwei Stufen besteht: a) der Feststellung des Tintentyps anhand der optischen Eigenschaften; die Ausrechnung von den Fingerprints der Eisengallustinten anhand der elementaren Zusammensetzung. Die Arbeit wird durch Fallbeispiele illustriert
Charakterisierung historischer Schreibtinten: optische Eigenschaften und elementare Zusammensetzung
No full textUnsere Forschung zielt in erster Linie darauf ab, eine soziogeografische Geschichte von Tinte, Pergament und Papyrus zu rekonstruieren, und umfasst die Materialanalyse der Schreibtinten der Schriftrollen vom Toten Meer, der antiken und hellenistischen Papyri in Ägypten, sowie der Koptischen und Europäischen Tinten des Mittelalters. Zu diesem Zweck haben wir ein Protokoll für die zerstörungsfreie Tintenanalyse entwickelt. Es besteht aus einem ersten Screening mit Hilfe der VIS/NIR Fotografie, um die Art der Tinte zu bestimmen, und der anschließenden Analyse mit der Röntgenfluoreszenzanalyse (RFA). Letztere spielt eine wichtige Rolle bei der Identifizierung der Metalle in den Rußtuschen und der Bestimmung der charakteristischen Zusammensetzung metallhaltiger Tinten, um zwischen den verschiedenen Tinten zu unterscheiden.
Der Vortrag bietet ein Panorama schwarzer historischer Schreibmittel und zeigt, dass die Materialanalyse einen wesentlichen Beitrag zur Beantwortung vieler kulturhistorischen Fragen leisten kann
Split Hopkinson Pressure Bar (SHPB) investigations of steel S355 specimens and complementary characterization methods
No full textThe workbook SHPB_S355.xlsx contains in the main spreadsheet S355_TestOverview an overview on the S355 specimens, which were tested in Split Hopkinson Pressure Bar (SHPB) and complementary quasi-static (QS) tests. The tests were conducted with notched hat-shaped specimens without a notch offset (S355_TestOverview/column geometry: “no offset”) and a small notch offset of x=0.35 mm (S355_TestOverview/column geometry: “offset”), cf. Fig. 1 [1]. Furthermore, for selected specimens, links are provided to DIC and bar strain measurement files as well as to evaluations from further characterization methods (microhardness, EBSD). For the boundary conditions at the SHPB projectile impact, the pressures of the compressor p, driving the projectile, and the associated projectile impact velocities are provided in SHPB_S355.xlsx.
The DIC displacement measurements are provided in FurtherMeasurements/DIC with frame output times in the file labels, which are associated with an imaginary trigger at the left end of the shortened incident bar (length 300 mm), which is considered within the SHPB simulation setup, see [1]. Furthermore, the DIC reference coordinate systems are provided as COS.jpg files in the respective DIC folders.
Starting from the strain signals at the bars, captured by strain gauges at the incident (file name BC_Inc) and transmission bar (BC_Trans), displacement boundary conditions (which are provided for the tests in FurtherMeasurements/BarDisplBCs) are calculated by eq. (12) in [1], incorporating the acoustic velocity equal to 4639 m/s at the bars and a correction factor. Fig. 1 shows the shear specimen geometry (lengths in mm) with the offset of the notches x.
For the quasi-static tests force(displacements)-values are directly provided in FurtherMeasurements/Fu_curves, which are considered from the relative displacements of the specimens, evaluated by DIC.
The Vickers microhardness (HV 0.01) distribution across the shear localization zone was assessed by QNESS 60A+ EVO (DIN EN ISO 6507-1) for quasi-statically and dynamically tested specimens, applying the small notch offset, such that the specimens did not fail in the localization region. Therefore, raw data is provided in FurtherMeasurements/Microhardness. For fitting the microhardness distribution perpendicularly to the shear bands (as i.e. provided for the SHPB specimen in [1]), representative microhardness profiles were considered. Similarly for specimens with the small notch offset, EBSD data on dynamic and quasi-static tests is provided in FurtherMeasurements/EBSD. The grain size distributions for positions at the notch and the undeformed region are included in the subdirectory ./GrainLists_Shortened and EBSD images in the PowerPoint Presentations. Further information as the sizes and misorientations of the single grains, is incorporated in the subfolders ./GrainLists_FurtherInf
Collaborative Structural Health Monitoring for Bridge Digital Twins
No full textStructural Health Monitoring (SHM) is an effective tool that not only reduces reliance on periodic inspections but also enhances them by analyzing the current state of a structure based on the latest structural data. Collaborative SHM, which integrates various SHM systems within the scope of bridge digital twins (BDTs), enhances infrastructure resilience and maintenance strategies. However, it faces challenges in integrating distributed sensor networks and requires interdisciplinary collaboration. In this work, various aspects of enhancing collaborative SHM with BDTs are presented.
As a pilot project, the Nibelungen Bridge in Worms (NBW), Germany, is introduced. Based on specific stakeholder and project requirements, various SHM systems havebeen installed on this bridge. To address these challenges, goal-oriented solutions have been developed and elaborated. Finally, conclusions and future outlooks are presented
Stand der Kenntnisse und Technik bzgl. Wasserstoffsicherheit
No full textIn dem Vortrag werden die aktuellen Herausforderungen für die Sicherheit von Wasserstofftechnologien skizziert, die sicherheitstechnischen Eigenschaften und physikalischen Eigenschaften von Wasserstoff im Vergleich zu anderen Energieträgern vorgestellt sowie Gefahren spezifisch im Zusammenhang mit Flüssigwasserstoff aufgezeigt. Im zweiten Teil wird ein kurzer Überblick über Regelwerke gegeben und typische Unfallszenarien anhand eines Fallbeispiels illustriert. Abschließend werden die von nationalen und internationalen Expertengruppen identifizierten Forschungslücken zusammengefasst und es wird auf relevante Datenbanken und Portale zur Wasserstoffsicherheit verwiesen
Intelligent damage detection in composite pressure vessels under varying environmental and operational conditions
No full textDespite proven approaches available in the literature, structural health monitoring by ultrasonic guided waves under varying environmental and operational conditions is still challenging. The use of machine learning approaches is discussed in this work, considering the complex problem of experimental damage detection under varying load conditions in a composite overwrapped pressure vessel for hydrogen storage. Specifically, unsupervised methods originally developed for image and time series classification are combined with ensemble voting to conceive reliable damage detection technique. This enables the effective combination of the predictions of multiple transducer pairs, even with a limited number of strong individual classifiers. A performance demonstration of the technique is presented using a real damage scenario dataset
Kinetics of anionic polymerization of <scp>β</scp>‐myrcene in hydrocarbon solvents
No full textAbstractThe kinetics of anionic polymerization of β‐myrcene initiated by sec‐butyllithium were examined in saturated and unsaturated hydrocarbon solvents, i.e. cyclohexane, cyclohexene, 4‐vinylcyclohexene and dl‐limonene. Polymerizations usually proceeded in a living manner, i.e. in the absence of termination and chain transfer reactions, in all solvents, to produce well‐defined polymyrcenes with high content (85%) of cis‐1,4 units. However, polymyrcenyllithium chains exhibited limited long‐term stability in 4‐vinylcyclohexene solution, most probably due to chain transfer to solvent. Reaction orders with respect to the concentration of active chains were found to be one‐quarter in cyclohexane increasing to one‐half in unsaturated solvents, indicating that the polymyrcenyllithium chains are present as tetrameric or dimeric associates, respectively. Apparent activation energies were found to be 81 kJ mol−1 in cyclohexane and 77 kJ mol−1 in dl‐limonene solution, which are close to the values obtained by quantum chemical calculations. © 2025 The Author(s). Polymer International published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry