TY - CONF A1 - Prager, Jens A1 - Lugovtsova, Yevgeniya A1 - Bulling, Jannis A1 - Held, Mathias A1 - Klärner, M. A1 - Winkler, T. A1 - Kroll, L. T1 - Akustische Bestimmung der Werkstoffparameter faserverstärkter Kunststoffe durch Auswertung der Dispersionseigenschaften geführter Wellen N2 - Akustische Verfahren eignen sich hervorragend zur Bestimmung der Werkstoffeigenschaften. Die Verfügbarkeit derartiger Verfahren ist vor allem für Kunststoffe wichtig, da deren Eigenschaften stark abhängig vom jeweiligen Herstellungsprozess und vom Alterungszustand sind. Exakte und vollständige Werte sind daher in Datenbanken oder von Herstellern nur begrenzt zu finden. Insbesondere die Entwicklung von Methoden zur Charakterisierung faserverstärkter Kunststoffe (FKV) ist nach wie vor Gegenstand der Forschung. Hier müssen anisotropiebedingt mehrere Kennwerte bestimmt werden. Da FKV zumeist als dünnwandige Bauteile zum Einsatz kommen, können die Werkstoffparameter aus den Dispersionseigenschaften der Lamb-Wellen, die sich in diesen Strukturen ausbreiten, abgeleitet werden. Dazu ist eine räumliche Abtastung des sich ausbreitenden Schallfelds erforderlich. In der vorliegenden Untersuchung wird dieser Ansatz für die relativ neue Werkstoffklasse der faserverstärkten Thermoplaste angewendet. Diese zeichnet ein ausgeprägtes Dämpfungsverhalten und eine Anisotropie der Materialparameter aus. Dazu wurde das Schallfeld im Ultraschallbereich mit einem Laser-Doppler-Vibrometers vermessen. Rechnerisch bestimmte Dispersionskurven wurden dann an die gemessenen Werte angepasst, womit die richtungsabhängigen Materialparameter bestimmt werden konnten. Im Vortrag wird das Messverfahren vorgestellt und auf spezielle Probleme, die sich z.B. aus dem Dämpfungsverhalten des Werkstoffs ergeben, eingegangen. Ausgewählte gemessene Werte werden mit den Ergebnissen von Referenzverfahren verglichen. T2 - DAGA 2021 - 47. Jahrestagung für Akustik CY - Vienna, Austria DA - 15.08.2021 KW - Ultraschall KW - Composites KW - Thermoplastische Kunststoffe PY - 2021 SP - 52 EP - 55 PB - Deutsche Gesellschaft für Akustik (DEGA) CY - Berlin AN - OPUS4-57340 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Becks, H. A1 - Lippold, L. A1 - Winkler, P. A1 - Moeller, M. A1 - Rohrer, M. A1 - Leusmann, T. A1 - Anton, D. A1 - Sprenger, B. A1 - Kähler, P. A1 - Rudenko, I. A1 - Andrés Arcones, Daniel A1 - Koutsourelakis, P. A1 - Unger, Jörg F. A1 - Weiser, M. A1 - Petryna, Y. A1 - Schnellenbach-Held, M. A1 - Lowke, D. A1 - Hessels, H. A1 - Lenzen, A. A1 - Zabel, V. A1 - Könke, C. A1 - Claßen, M. A1 - Hegger, J. T1 - Neuartige Konzepte für die Zustandsüberwachung und -analyse von Brückenbauwerken – Einblicke in das Forschungsvorhaben SPP100+ N2 - Die Brückeninfrastruktur in Deutschland und Europa steht aufgrund steigender Verkehrslasten und alternder Bauwerke vor erheblichen Herausforderungen. Das DFG-Schwerpunktprogramm 2388 „Hundert plus – Verlängerung der Lebensdauer komplexer Baustrukturen durch intelligente Digitalisierung“ (SPP100+) strebt an, durch digitale Innovationen und prädiktive Instandhaltungsstrategien die Nutzungsdauer bestehender Brückenbauwerke zu verlängern. Der vorliegende Beitrag fokussiert sich auf das SPP100+ zugehörige Cluster „Monitoring und Simulation“, das sieben Teilprojekte umfasst. Die Projekte entwickeln fortschrittliche Methoden zur Überwachung und Zustandsbewertung von Brücken mittels Digitaler Zwillinge, hochauflösender Sensortechnik und numerischer Simulationen. Innovative Ansätze wie nichtlineare Modellanpassungen, stochastische Methoden und künstliche Intelligenz ermöglichen eine präzise und frühzeitige Identifizierung potenzieller Schäden. Die Kombination aus kontinuierlichem Bauwerksmonitoring und effizienter Datenauswertung ist entscheidend für die langfristige Sicherheit und Langlebigkeit bestehender Brücken und trägt darüber hinaus zur Ressourcenschonung bei. KW - Bauwerkserhaltung KW - Brückenbau KW - Monitoring KW - Lebensdauer PY - 2024 DO - https://doi.org/10.37544/0005-6650-2024-10-63 SN - 0005-6650 VL - 99 IS - 10 SP - 327 EP - 338 PB - VDI Verlag-eLibrary - technisches Wissen für Ingenieur*innen CY - Düssledorf AN - OPUS4-61563 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Winkler, T. T1 - Osteoclastic Bioresorption of Biomaterials: 3D-Imaging and Quantification T2 - 36. Jahrestagung, European Soc. for Artificial Organs (ESAO), Université de Technologie de Compiègne CY - Compiègne, France DA - 2009-09-02 PY - 2009 AN - OPUS4-19680 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkler, T. A1 - Hoenig, E. A1 - Huber, G. A1 - Janssen, R. A1 - Fritsch, D. A1 - Gildenhaar, Renate A1 - Berger, Georg A1 - Morlock, M.M. A1 - Schilling, A.F. T1 - Osteoclastic bioresorption of biomaterials: Two- and three-dimensional imaging and quantification N2 - Purpose: Bioresorbable materials have been developed in the hope that the body will replace them with newly formed tissue. The first step of this remodeling process in bone is the bioresorption of the material by osteoclasts. The aim of this study was to analyze osteoclastic resorption of biomaterials in vitro using the commonly used two-dimensional methods of light-microscopy (LM) and scanning electron microscopy (SEM) in comparison with infinite focus microscopy (IFM), a recently developed imaging method allowing for three-dimensional surface analysis. Methods: Human hematopoietic stem cells were cultivated in the presence of the cytokines M-CSF and RANK-L for 4 weeks directly on dentin and a calcium phosphate cement. Osteoclast development was surveyed with standard techniques. After removal of the cells, resorption was characterized and quantified by LM, SEM and IFM. Results: Osteoclast cultures on the biomaterials presented the typical osteoclast-specific markers. On dentin samples LM, SEM as well as IFM allowed for discrimination of resorption. Quantification of the resorbed area showed a linear correlation between the results (LM vs. SEM: r=0.996, p=0.004; SEM vs. IFM: r=0.989, p=0.011; IFM vs. LM: r=0.995). It was not possible to demarcate resorption pits on GB14 using LM or SEM. With IFM, resorption on GB14 could be visualized and quantified two- and three-dimensionally. KW - Biomaterial KW - Three-dimensional KW - IFM KW - Osteoclast KW - Dentin KW - Calcium phosphate PY - 2010 SN - 0391-3988 VL - 33 IS - 4 SP - 198 EP - 203 PB - Wichtig Ed. CY - Milano [u.a.] AN - OPUS4-21621 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkler, T. A1 - Hoenig, E. A1 - Gildenhaar, Renate A1 - Berger, Georg A1 - Fritsch, D. A1 - Janssen, R. A1 - Morlock, M.M. A1 - Schilling, A.F. T1 - Volumetric analysis of osteoclastic bioresorption of calcium phosphate ceramics with different solubilities N2 - Commonly, to determine osteoclastic resorption of biomaterials only the resorbed area is measured. The depth of the resorption pit, however, may also be important for the performance of a material. To generate such data we used two calcium phosphate ceramics (Ca10 and Ca2). The solubility of the materials was determined according to DIN EN ISO 10993-14. They were scanned three-dimensionally using infinite focus microscopy and subsequently cultivated for 4 weeks in simulated body fluid without (control) or with human osteoclasts. After this cultivation period osteoclasts number was determined and surface changes were evaluated two- and three-dimensionally. Ca10 and Ca2 showed solubilities of 11.0 ± 0.5 and 23.0 ± 2.2 mg g-1, respectively. Both materials induced a significant increase in osteoclast number. While Ca10 did not show osteoclastic resorption, Ca2 showed an increased pit area and pit volume due to osteoclastic action. This was caused by an increased average pit depth and an increased number of pits, while the average area of single pits did not change significantly. The deduced volumetric osteoclastic resorption rate (vORR) of Ca2 (0.01–0.02 µm3 µm-2 day-1) was lower than the remodelling speed observed in vivo (0.08 µm3 µm-2 day-1), which is in line with the observation that implanted resorbable materials remain in the body longer than originally expected. Determination of volumetric indices of osteoclastic resorption might be valuable in obtaining additional information about cellular resorption of bone substitute materials. This may help facilitate the development of novel materials for bone substitution. KW - Biodegradation KW - Surface analysis KW - Simulated body fluid KW - Osteoclasts KW - Calcium phosphate ceramics PY - 2010 DO - https://doi.org/10.1016/j.actbio.2010.04.015 SN - 1742-7061 VL - 6 IS - 10 SP - 4127 EP - 4135 PB - Elsevier CY - Amsterdam AN - OPUS4-22554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Braga, Daniel S. A1 - Pedersen, Angus A1 - Riyaz, Mohd A1 - Barrio, Jesús A1 - Bagger, Alexander A1 - Neckel, Itamar T. A1 - Mariano, Thiago M. A1 - Winkler, Manuel E. G. A1 - Stephens, Ifan E. L. A1 - Titirici, Maria‐Magdalena A1 - Nagao, Raphael T1 - Inside back cover image for the article "In situ structural evolution and activity descriptor of atomically dispersed catalysts during nitrate electroreduction" N2 - This cover illustrates the electrosynthesis of ammonia through the reduction of nitrate ions on metallic clusters formed from single atom catalysts. The artwork highlights the catalytic interface where molecular transformations occur, linking nanoscale reactions to sustainable fertilizer production. By converting pollutants into value-added products, this work envisions a green pathway toward circular nitrogen management and enhanced agricultural sustainability. More details can be found in the Research Article (DOI: 10.1002/advs.202510282) by Maria-Magdalena Titirici, Raphael Nagao, and co-workers. KW - Single atom KW - Nitrate reduction KW - In situ KW - Structure-activity-selectivity PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-652626 DO - https://doi.org/10.1002/advs.71951 SN - 2198-3844 VL - 12 IS - 39 SP - 1 PB - Wiley-VCH CY - Weinheim AN - OPUS4-65262 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Braga, Daniel S. A1 - Pedersen, Angus A1 - Riyaz, Mohd A1 - Barrio, Jesús A1 - Bagger, Alexander A1 - Neckel, Itamar T. A1 - Mariano, Thiago M. A1 - Winkler, Manuel E. G. A1 - Stephens, Ifan E. L. A1 - Titirici, Maria‐Magdalena A1 - Nagao, Raphael T1 - In situ structural evolution and activity descriptor of atomically dispersed catalysts during nitrate electroreduction N2 - Single‐Atom Catalysts (SAC) have emerged as a promising class of materials for various catalytic applications, including the electrochemical nitrate reduction reaction (eNO3RR) and consequently ammonia production. While the efficiency and selectivity of these materials have been extensively highlighted for the eNO3RR, the in situ evolution to their structure and composition during electrocatalysis is largely unexplored and lacks catalyst design principles. To solve this, we investigated a series of high utilization metal‐nitrogen‐carbon (MNC) SACs (M = Cr, Fe, Co, Ni, and Cu) for eNO3RR. Except for CuNC, which selectively produced nitrite, all catalysts exhibited Faradaic efficiencies (FE) for ammonia exceeding 50%. NiNC demonstrated the highest performance (FE of 78.0 ± 2.9% at −0.4 V versus reversible hydrogen electrode (RHE) at pH 13 and maximum ammonia production rate of 615.7 ± 176.5 µmol·h−1·, corresponding to an energy efficiency of 15.1 ± 1.4% at −0.6 VRHE), followed by CoNC. In situ Synchrotron X‐ray fluorescence (SXRF) mapping at various cathodic potentials (from open circuit potential to 0.0 VRHE and then −0.6 VRHE at 100 mV steps) revealed significant mobility of Ni within the carbon matrix, leading to the formation of metallic clusters from 0.0 VRHE. Similar in situ metal clustering is observed for CoNC. Structure‐activity plots are generated from both MNC literature and results obtained here, finding a clear trend between OH binding energy and turnover frequency, with the high activity of NiNC and CoNC in this work explained by their stronger OH binding in the metallic structure compared to their SAC coordination. This work therefore, reveals the structure‐activity‐stability of MNCs for eNO3RR and provides a simple descriptor for identifying highly active eNO3RR catalysts and their in situ structural evolution. KW - Single atom KW - Nitrate reduction KW - Structure-activity-selectivity KW - In situ PY - 2025 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-640353 DO - https://doi.org/10.1002/advs.202510282 SN - 2198-3844 VL - 12 IS - 39 SP - 1 EP - 14 PB - Wiley-VCH CY - Weinheim AN - OPUS4-64035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -