TY - JOUR A1 - Wessling, S. A1 - Kessels, W. A1 - Schmidt, Martin A1 - Krause, Ulrich T1 - Investigating dynamic underground coal fires by means of numerical simulation N2 - Uncontrolled burning or smoldering of coal seams, otherwise known as coal fires, represents a worldwide natural hazard. Efficient application of fire-fighting strategies and prevention of mining hazards require that the temporal evolution of fire propagation can be sufficiently precise predicted. A promising approach for the investigation of the temporal evolution is the numerical simulation of involved physical and chemical processes. In the context of the Sino-German Research Initiative ‘Innovative Technologies for Detection, Extinction and Prevention of Coal Fires in North China,’ a numerical model has been developed for simulating underground coal fires at large scales. The objective of such modelling is to investigate observables, like the fire propagation rate, with respect to the thermal and hydraulic parameters of adjacent rock. In the model, hydraulic, thermal and chemical processes are accounted for, with the last process complemented by laboratory experiments. Numerically, one key challenge in modelling coal fires is to circumvent the small time steps resulting from the resolution of fast reaction kinetics at high temperatures. In our model, this problem is solved by means of an ‘operator-splitting’ approach, in which transport and reactive processes of oxygen are independently calculated. At high temperatures, operator-splitting has the decisive advantage of allowing the global time step to be chosen according to oxygen transport, so that time-consuming simulation through the calculation of fast reaction kinetics is avoided. Also in this model, because oxygen distribution within a coal fire has been shown to remain constant over long periods, an additional extrapolation algorithm for the coal concentration has been applied. In this paper, we demonstrate that the operator-splitting approach is particularly suitable for investigating the influence of hydraulic parameters of adjacent rocks on coal fire propagation. A study shows that dynamic propagation strongly depends on permeability variations. For the assumed model, no fire exists for permeabilities k < 10-10 m2, whereas the fire propagation velocity ranges between 340 m a-1 for k = 10-8 m2, and drops to lower than 3 m a-1 for k = 5 × 10-10 m2. Additionally, strong temperature variations are observed for the permeability range 5 × 10-10 m2 < k < 10-8 m2. KW - Numerical solutions KW - Underground coal fires KW - Hydrothermal systems PY - 2008 DO - https://doi.org/10.1111/j.1365-246X.2007.03568.x SN - 0956-540X SN - 1365-246X VL - 172 IS - 1 SP - 439 EP - 454 PB - Blackwell CY - Oxford AN - OPUS4-16649 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mielentz, Frank A1 - Milmann, Boris A1 - Krause, Martin A1 - Müller, W. A1 - Crail, S. T1 - Zerstörungsfreie Risscharakterisierung in Betonbauteilen mit Ultraschall N2 - Die Risstiefenbestimmung in Festen Fahrbahnen ist hinsichtlich der Dauerhaftigkeit der Konstruktion von wesentlichem Interesse. Im Rahmen eines gemeinsamen Forschungsvorhabens mit der DB AG wurden aus der Literatur bekannte Ansätze bewertet und darauf aufbauend ein Verfahren zur bildgebenden Rissdarstellung entwickelt. Rissüberbrückende Bewehrung sowie Kontaktstellen zwischen den Rissflanken wirken als Schallbrücken und erschweren die Risscharakterisierung, wie bei einem Einsatz an einer Betriebserprobungsstrecke festgestellt wurde. Ein aus der Literatur bekanntes Verfahren der einfachen Laufzeitmessung erwies sich für die Tiefenbestimmung von realen verunreinigten Rissen als ungeeignet. T2 - Fachtagung Bauwerksdiagnose - Praktische Anwendungen Zerstörungsfreier Prüfungen CY - Leipzig, Germany DA - 25.10.2001 PY - 2001 VL - 76-CD SP - 1 EP - 10 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-1188 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hachenberger, Y. U. A1 - Rosenkranz, Daniel A1 - Kromer, C. A1 - Krause, B. C. A1 - Dreiack, N. A1 - Kriegel, F. L. A1 - Kozmenko, E. A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Bierkandt, F. S. A1 - Laux, P. A1 - Panne, Ulrich A1 - Luch, A. T1 - Nanomaterial Characterization in Complex Media - Guidance and Application N2 - A broad range of inorganic nanoparticles (NPs) and their dissolved ions possess a possible toxicological risk for human health and the environment. Reliable and robust measurements of dissolution effects may be influenced by the sample matrix, which challenges the analytical method of choice. In this study, CuO NPs were investigated in several dissolution experiments. Two analytical techniques (dynamic light scattering (DLS) and inductively-coupled plasma mass spectrometry (ICP-MS)) were used to characterize NPs (size distribution curves) time-dependently in different complex matrices (e.g., artificial lung lining fluids and cell culture media). The advantages and challenges of each analytical approach are evaluated and discussed. Additionally, a direct-injection single particle (DI sp)ICP-MS technique for assessing the size distribution curve of the dissolved particles was developed and evaluated. The DI technique provides a sensitive response even at low concentrations without any dilution of the complex sample matrix. These experiments were further enhanced with an automated data evaluation procedure to objectively distinguish between ionic and NP events. With this approach, a fast and reproducible determination of inorganic NPs and ionic backgrounds can be achieved. This study can serve as guidance when choosing the optimal analytical method for NP characterization and for the determination of the origin of an adverse effect in NP toxicity. KW - Nanon KW - Characterization KW - SpICP-MS KW - Matrix KW - Dissolution PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-572138 DO - https://doi.org/10.3390/nano13050922 VL - 13 IS - 5 SP - 1 EP - 19 AN - OPUS4-57213 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kaudelka, Sven A1 - Hofmann-Böllinghaus, Anja A1 - Hauswaldt, S. A1 - Krause, U. T1 - Auswirkung von Zündquellen und Systembeschaffenheit auf das Brandverhalten EPS-basierter Wärmedämm-Verbundsysteme N2 - Gegenstand des Aufsatzes ist die experimentelle Untersuchung der Auswirkungen verschiedener Zündquellen sowie der Systembeschaffenheit auf das Brandverhalten EPS-basierter Wärmedämm-Verbundsysteme (WDVS). Dazu wurden Brände ausgewertet, die mit EPS-basierten WDVS in Verbindung stehen. Ergebnis dieser Auswertung war, dass nicht wie bisher angenommen der Brand in dem Gebäude (z. B. der Wohnungsbrand), sondern vielmehr der Brand außerhalb des Gebäudes, insbesondere der des Abfallbehälters, das häufigste und kritischste Brandszenario für EPS-basierte WDVS darstellt. Daraufhin wurden an der BAM Bundesanstalt für Materialforschung und -prüfung Brandversuche in der Single Burning Item-Prüfeinrichtung (SBI) an nicht intakten EPS-basierten WDVS-Ausschnitten durchgeführt. Mit zunehmender Beschädigungsgröße und -tiefe stieg die vom System freigesetzte Wärmefreisetzungsrate an. Zusätzlich werden Brandversuche eines Sockelbrandszenarios mit einer abfallbehälteräquivalenten Brandlast vorgestellt. Aus den Brandversuchen werden Empfehlungen zur Verbesserung der Systemsicherheit abgeleitet.------------------------------------------------------------------------------------------------------------------------------------------------- The influence of different ignition sources and conditions of the systems on the fire behaviour of external thermal insulating systems (ETICS) have been investigated experimentally. As a basis of the investigations real cases with EPS based ETICS have been analysed. The analysis showed that the fire in front of the building is the most common and critical fire scenario for these systems. These fires are often caused by waste containers. This result contradicts the former common assumption that the fire inside the building is the most critical fire scenario for ETICS. Intermediate scale experiments in the Single Burning Item (SBI) test apparatus have been performed at BAM with ETICS specimens. The render of the systems was partially damaged. The measured heat release rate of the specimens increased significantly with size and depths of the damages. Additionally results of large scale experiments with a waste container equivalent ignition source are presented and recommendations to enhance fire safety of these systems are given. KW - Fassaden KW - Wärmedämm-Verbundsystem (WDVS) KW - Expandiertes Polystyrol (EPS) KW - Brandverhalten von Baustoffen KW - Bemessungsbrandszenario KW - Sockelbrand KW - Abfallbehälter KW - ET/CS KW - External thermal insulation composite system KW - Expanded polystyrene KW - Waste containers KW - Released heat rate KW - Plinths-based fire scenario KW - Single burning item test KW - Single Burning Item-Prüfeinrichtung (SBI) KW - Wärmefreisetzungsrate KW - DIBt-Empfehlung KW - Façades KW - Brandschutz - Fire protection engineering PY - 2015 DO - https://doi.org/10.1002/bapi.201510023 SN - 0171-5445 SN - 1437-0980 VL - 37 IS - 4 SP - 205 EP - 212 PB - Ernst CY - Berlin AN - OPUS4-33835 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieg, H. A1 - Braeuning, C. A1 - Kunz, B. M. A1 - Daher, H. A1 - Kästner, C. A1 - Krause, B.-C. A1 - Meyer, T. A1 - Jalili, P. A1 - Kogeveen, K. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Burel, A. A1 - Chevance, S. A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Laux, P. A1 - Braeuning, A. A1 - Gauffre, F. A1 - Fessard, V. A1 - Meijer, J. A1 - Estrela-Lopis, I. A1 - Thünemann, Andreas A1 - Luch, A. A1 - Lampen, A. T1 - Uptake and molecular impact of aluminum-containing nanomaterials on human intestinal caco-2 cells N2 - Aluminum (Al) is one of the most common elements in the earth crust and increasingly used in food, consumer products and packaging. Its hazard potential for humans is still not completely understood. Besides the metallic form, Al also exists as mineral, including the insoluble oxide, and in soluble ionic forms. Representatives of these three species, namely a metallic and an oxidic species of Al-containing nanoparticles and soluble aluminum chloride, were applied to human intestinal cell lines as models for the intestinal barrier. We characterized physicochemical particle parameters, protein corona composition, ion release and cellular uptake. Different in vitro assays were performed to determine potential effects and molecular modes of Action related to the individual chemical species. For a deeper insight into signaling processes, microarray transcriptome analyses followed by bioinformatic data analysis were employed. The particulate Al species showed different solubility in biological media. Metallic Al nanoparticles released more ions than Al2O3 nanoparticles, while AlCl3 showed a mixture of dissolved and agglomerated particulate entities in biological media. The protein corona composition differed between both nanoparticle species. Cellular uptake, investigated in transwell experiments, occurred predominantly in particulate form, whereas ionic Al was not taken up by intestinal cell lines. Transcellular transport was not observed. None of the Al species showed cytotoxic effects up to 200 mg Al/mL. The transcriptome analysis indicated mainly effects on oxidative stress pathways, xenobiotic metabolism and metal homeostasis. We have shown for the first time that intestinal cellular uptake of Al occurs preferably in the particle form, while toxicological effects appear to be ion-related. KW - Small-angle x-ray scattering KW - SAXS KW - Nanopatricle PY - 2018 DO - https://doi.org/10.1080/17435390.2018.1504999 SN - 1743-5390 VL - 12 IS - 9 SP - 992 EP - 1013 PB - Taylor & Francis AN - OPUS4-47432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Sieg, H. A1 - Lehmann, C. A1 - Kästner, Claudia A1 - Krause, B. A1 - Burel, A. A1 - Chevance, S. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Tentschert, J. A1 - Bräuning, A. A1 - Laux, A. A1 - Thünemann, Andreas A1 - Loipis, I. E. A1 - Fessard, V. A1 - Luch, A. A1 - Lampen, A. T1 - Effects of Al-, Ti- and Zn-containing nanomaterials on cell lines in vitro N2 - Among the different tested endpoints, Al- and Ticontaining nanomaterials did notshowany toxicity in intestinal cell lines in vitro. Nevertheless, this absence of effect was not due to an absence of exposure, since particle-specific uptake was reported. Metal particle uptake over a long time period might therefore be relevant for risk assessment of aluminum- and titanium-containing food products. T2 - 52nd Congress of the European-Societies-of-Toxicology (EUROTOX) CY - Seville, Spain DA - 04.09.2017 KW - Nanoparticles PY - 2017 DO - https://doi.org/10.1016/j.toxlet.2016.06.1954 SN - 0378-4274 VL - 258 SP - S272 PB - Elsevier Ltd. AN - OPUS4-40939 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fiedler Bremer, C. A1 - Scholz, R. A1 - Myslicki, S. A1 - Starke, P. A1 - Boller, C. A1 - Walther, F. A1 - Krause, Martin T1 - NDT-based characteriazation of timber and vulcanized fiber for civil infrastructure N2 - The paper addresses beech wood as well as vulcanized fiber and discusses the results obtained when using acoustic emission and thermography as non-destructive testing techniques along tensile and load increase fatigue tests to characterize the wooden material’s behavior under increasing fatigue loads to get enhanced information regarding the fatigue behavior of both materials. Reference is mainly made to the materials’ anisotropic and microstructural behavior and what implications this has with respect to the materials’ strength. The influence of moisture is discussed, as well as parameters that may deserve monitoring in the sense of structural health monitoring to be applied in timber structures in general. T2 - NDT-CE 2015 - International symposium non-destructive testing in civil engineering CY - Berlin, Germany DA - 15.09.2015 KW - Ermüdung KW - Belastungsversuch KW - Thermographie KW - ZfP KW - Timber PY - 2015 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-346377 UR - https://www.ndt.net/?id=18419 SN - 1435-4934 VL - 20 IS - 11 SP - 1 EP - 11 PB - NDT.net CY - Kirchwald AN - OPUS4-34637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jordan, T. A1 - Askar, Enis A1 - Holtappels, Kai A1 - Deeg, S. A1 - Jopen, M. A1 - Stoll, U. A1 - Reinecke, E.-A. A1 - Krause, U. A1 - Beyer, M. A1 - Markus, D. T1 - Stand der Kenntnisse und Technik bezüglich Wasserstoffsicherheit N2 - Die Einführung von Wasserstoff als sicherer Energieträger braucht eine robuste Wissensbasis, darauf aufgebaute Werkzeuge zur Auslegung und Sicherheitsbewertung von Wasserstofftechnologien und ein international harmonisiertes Regelwerk. Viele der innovativen Technologien implizieren Wasserstoff bei hohen Drücken und/oder kryogenen Temperaturen, mit denen in verteilten Anwendungen erstmalig private Nutzer in Kontakt kommen. Um überkonservative, teure Sicherheitslösungen zu vermeiden, gleichzeitig aber die Einsetzbarkeit und Sicherheit von Wasserstoffanwendungen zu demonstrieren und die Akzeptanz für die Technologie aufrecht zu halten, muss auch die Sicherheitsforschung mit den Trends der technologischen Entwicklung Schritt halten, oder sie besser noch antizipieren. So beschreibt dieser Überblicksartikel nicht nur den gegenwärtigen Stand der Kenntnisse und Technik bezüglich Wasserstoffsicherheit, sondern auch ihre Weiterentwicklung. KW - Alternative Energieträger KW - Explosionsschutz KW - Flüssigwasserstoff KW - Unfallszenarien KW - Wasserstoffspeicherung KW - Sicherheitsbewertung KW - Regelsetzung KW - Gefährdungs- und Risikobeurteilung PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-593629 DO - https://doi.org/10.1002/cite.202300141 SN - 0009-286X VL - 96 IS - 1-2 SP - 1 EP - 20 PB - Wiley-VCH AN - OPUS4-59362 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krause, B. A1 - Meyer, T. A1 - Sieg, H. A1 - Kästner, Claudia A1 - Reichardt, P. A1 - Tentschert, J. A1 - Jungnickel, H. A1 - Estrela-Lopis, I. A1 - Burel, A. A1 - Chevance, S. A1 - Gauffre, F. A1 - Jalili, P. A1 - Meijer, J. A1 - Böhmert, L. A1 - Braeuning, A. A1 - Thünemann, Andreas A1 - Emmerling, Franziska A1 - Fessard, V. A1 - Laux, P. A1 - Lampen, A. A1 - Luch, A. T1 - Characterization of aluminum, aluminum oxide and titanium dioxide nanomaterials using a combination of methods for particle surface and size analysis N2 - The application of appropriate analytical techniques is essential for nanomaterial (NM) characterization. In this study, we compared different analytical techniques for NM analysis. Regarding possible adverse health effects, ionic and particulate NM effects have to be taken into account. As NMs behave quite differently in physiological media, special attention was paid to techniques which are able to determine the biosolubility and complexation behavior of NMs. Representative NMs of similar size were selected: aluminum (Al0) and aluminum oxide (Al2O3), to compare the behavior of metal and metal oxides. In addition, titanium dioxide (TiO2) was investigated. Characterization techniques such as dynamic light scattering (DLS) and nanoparticle tracking analysis (NTA) were evaluated with respect to their suitability for fast characterization of nanoparticle dispersions regarding a particle's hydrodynamic diameter and size distribution. By application of inductively coupled plasma mass spectrometry in the single particle mode (SP-ICP-MS), individual nanoparticles were quantified and characterized regarding their size. SP-ICP-MS measurements were correlated with the information gained using other characterization techniques, i.e. transmission electron microscopy (TEM) and small angle X-ray scattering (SAXS). The particle surface as an important descriptor of NMs was analyzed by X-ray diffraction (XRD). NM impurities and their co-localization with biomolecules were determined by ion beam microscopy (IBM) and confocal Raman microscopy (CRM). We conclude advantages and disadvantages of the different techniques applied and suggest options for their complementation. Thus, this paper may serve as a practical guide to particle characterization techniques. KW - Small-angle X-ray scattering KW - SAXS PY - 2018 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-447057 DO - https://doi.org/10.1039/C8RA00205C SN - 2046-2069 VL - 8 IS - 26 SP - 14377 EP - 14388 PB - The Royal Society of Chemistry AN - OPUS4-44705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Zakel, S. A1 - Schröder, Volkmar A1 - Askar, Enis A1 - Gabel, D. A1 - Hirsch, W. A1 - Kleinert, J. A1 - Krause, U. A1 - Krietsch, Arne A1 - Meistes, J. A1 - Sachtleben, A. A1 - Schmidt, Martin T1 - Sicherheitstechnische Kenngrößen des Explosionsschutzes von hybriden Stoffgemischen - Normungsfähige Bestimmungsverfahren N2 - In diesem Verbundvorhaben werden standardisierte Messverfahren für hybride Gemische erarbeitet, die der Bestimmung sicherheitstechnischer Kenngrößen des Explosionsschutzes dienen. Unter einem hybriden Gemisch wird dabei ein mehrphasiges System aus Brenngas oder brennbarem Dampf, sowie Luft und brennbarem Staub verstanden. Die Veröffentlichung der Ergebnisse erfolgt in einem Abschlussbericht und als DIN-Spezifikation (DIN SPEC). Diese DIN SPEC versetzt Prüfinstitute und Industrie in die Lage, Explosionsgefahren beim Betrieb technischer Anlagen mit hybriden Gemischen einzuschätzen und damit Prozesse sowohl sicherer als auch effizienter zu steuern. Dieses Projekt wird im Rahmen des WIPANOProgramms (Wissens- und Technologietransfer durch Patente und Normen) vom BMWi gefördert. T2 - 14. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit CY - Köthen, Germany DA - 07.11.2019 KW - Explosionsschutz KW - Sicherheitstechnische Kenngrößen KW - Hybride Gemische KW - Normung PY - 2019 SN - 978-3-89746-220-5 SP - 73 CY - Frankfurt am Main AN - OPUS4-49954 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -