TY - CONF A1 - Köhler, B. A1 - Schubert, F. A1 - Algernon, Daniel A1 - Gardei, André A1 - Mielentz, Frank A1 - Krause, Martin ED - Thompson, D. O. T1 - Experimental study of elastic waves in concrete for NDE in civil engineering N2 - Laser vibrometric contactless sound field measurements at a concrete test block are presented. Both excitation by an ultrasonic probe and by an impactor were used. The wave modes can be identified by their geometric wave forms and propagation velocities. Additionally, numerical simulation of the experimental situation is used to support this interpretation. Possible applications of the presented technique are discussed. ©2005 American Institute of Physics T2 - 31th Annual Review of Progress in Quantitative Nondestructive Evaluation CY - Golden, CO, USA DA - 2004-07-25 KW - Ultraschall KW - Impact-Echo KW - Wellenausbreitung KW - Visualisierung KW - Modellierung PY - 2005 SN - 0-7354-0245-0 DO - https://doi.org/10.1063/1.1916840 SN - 0743-0760 SN - 0094-243X N1 - Serientitel: AIP conference proceedings – Series title: AIP conference proceedings IS - 760 SP - 1439 EP - 1445 PB - American Institute of Physics CY - Melville, NY AN - OPUS4-5480 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Algernon, Daniel A1 - Gräfe, Boris A1 - Mielentz, Frank A1 - Köhler, B. A1 - Schubert, F. T1 - Imaging of the Elastic Wave Propagation in Concrete Using Scanning Techniques: Application for Impact-Echo and Ultrasonic Echo Methods N2 - Acoustic NDT methods like ultrasonic echo and impact-echo are successfully used for NDT of concrete structures. This paper describes useful techniques for a detailed experimental study of the elastic wave propagation, which is highly relevant for the interpretation of the results obtained from practical measurement applications. By using a scanning laser vibrometer it becomes possible to obtain a 2D visualization of the elastic waves propagating along the surfaces of concrete specimens. Time slices are prepared so that the wave field becomes apparent. In order to visualize especially the surface wave propagation a similar technique using a scanning system with a piezoelectric sensor is applied. The results obtained provide an appropriate basis for the comparison with numerical results from 3-D Elastodynamic finite integration technique (EFIT) calculations, which is demonstrated here. Examples are presented for the application with phased array ultrasonic echo, air-coupled ultrasonic echo and impact-echo. KW - Ultrasonic-echo KW - Impact-echo KW - Laser vibrometer KW - Visualization of wave propagation KW - Elastodynamic finite integration technique (EFIT) PY - 2008 UR - http://www.springerlink.com/content/v739785102l6367x/fulltext.pdf DO - https://doi.org/10.1007/s10921-008-0034-4 SN - 0195-9298 SN - 1573-4862 VL - 27 IS - 1-3 SP - 83 EP - 97 PB - Plenum Press CY - New York, NY AN - OPUS4-18031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zinke, R. A1 - Virothi, N. A1 - Köhler, F. A1 - Klippel, A. A1 - Schalau, Sebastian A1 - Krause, U. T1 - Experimental measurement of initial evaporation mass flows from gasoline spills and comparison with empirical models N2 - In this paper, we investigate the evaporation mass flow originating from spills of gas-oline. Large spills of gasoline may form during partial or complete roof sinkings or inthe case of perforations at various deck fittings at external floating roof tanks usedfor the storage. Additionally, spills may form in the retention area in the case of leak-ages at pipes or at the hull. The aim is to predict the order of magnitude of real-scaleevaporation mass flow. The determined evaporation mass flows will be used in arelated project as input values for subsequent dispersion modeling in the vicinity ofthe tanks. This is relevant for questions of fire and explosion protection as well as forenvironmental protection aspects in tank farms or refineries, which use externalfloating roof tanks. The measurements presented in this paper were compared withpredictions by empirical models and investigations of evaporations from small floorspills, round-bottom flask, or from Petri dishes published in the literature. The maingoal of this paper is to test the applicability of empirical models to provide reasonableevaporation mass flows as input for CFD dispersion simulations. KW - Spill evaporation PY - 2019 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-504322 DO - https://doi.org/10.1002/prs.12128 VL - 39 IS - 3 SP - e12128 PB - Wiley Online Libary AN - OPUS4-50432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zinke, R. A1 - Wothe, K. A1 - Dugarev, D. A1 - Götze, O. A1 - Köhler, F. A1 - Schalau, Sebastian A1 - Krause, U. T1 - Uncertainty consideration in CFD-models via response surface modeling: Application on realistic dense and light gas dispersion simulations N2 - Major accidents in the process industry often lead to the release of light or dense gases, which can mean a thread to employees, local residents or to the environment. Possible scenarios are therefore analyzed and evaluated in advance for approval issues. There is a trend, where simple empirical models are being replaced with more complex numerical models. Gaussian dispersion models or models based on dimensional analysis approaches are for example, increasingly replaced by CFD simulations. The main reason for this is the potentially higher accuracy. However, usually scenarios using sharp parameter values are calculated, since comprehensive consideration of parameter distributions via Monte Carlo or Latin Hypercube Sampling fails due to the numerical effort. This includes the risk that the influence of uncertainties on the simulation results is not taken into account. Response surface methods offer an alternative, with which the CFD problem can be mapped onto an algebraic surrogate model. If this is sufficiently precise, parameter sampling can also be carried out with the surrogate as well, as shown in some publications. Previous investigations only demonstrated the basic principle using trivial dispersion models. In this paper two realistic CFD simulations from the plant safety area are considered: VOC emissions from a storage tank and near-ground dense gas emissions. The entire procedure of response surface determination and parameter studies was automated and parallelized for high-performance-computing, and is carried out on the underlying CFD grids. For the CFD simulations as well as for all visualizations, the commercial software ANSYS CFX and the open source software OpenFOAM were used. The aim of this paper is to demonstrate the method using industry-relevant applications as well as to show how this can be used in practical engineering applications. The quality of surrogate modeling, the numerical effort and advantages that can result from the procedure are discussed as well as advantages which may result from taking parameter uncertainties into account in safety studies. KW - CFD KW - Accidental release KW - Response surface methods KW - Air dispersion modeling PY - 2022 DO - https://doi.org/10.1016/j.jlp.2021.104710 SN - 0950-4230 VL - 75 SP - 1 EP - 10 PB - Elsevier CY - Amsterdam AN - OPUS4-56887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bruhn, D. A1 - Köhler, S. A1 - Regenspurg, S. A1 - Schumann, F. A1 - Bäßler, Ralph A1 - Dunkelberg, E. A1 - Huenges, E. A1 - Frick, M. A1 - Hirschl, B. A1 - Sass, I. T1 - Positionspapier Wärmeversorgung in Berlin und Brandenburg durch GeoEnergie - Empfehlungen der GeoEnergie Allianz Berlin Brandenburg zu Forschung und Umsetzung N2 - Das gesellschaftliche Ziel der Defossilisierung der Energieversorgung erfordert eine disruptive Veränderung der Wärmebereitstellung. In Berlin und in den größten Brandenburger Städten Potsdam und Cottbus werden noch über 80 % der Nutzwärme über fossile Energieträger bereitgestellt. Die notwendigen Veränderungen erfordern Lösungen, die den tiefen Untergrund der Region nutzen. Allein die Nutzung der tiefen Geothermie kann mindestens 25% des Wärmebedarfs in Deutschland decken. Die Infrastruktur zur Verteilung dieser erneuerbaren Wärme ist bereichsweise vorhanden. Sie muss allerdings lokal und in ländlichen Gebieten weiter ausgebaut werden. Für die Sektoren Strom und Verkehr steht zwar Energie insbesondere aus Sonne und Wind bereit, aber wegen des zeitlich variablen Angebots besteht ein erheblicher Bedarf an großtechnischen Speichern für Strom und Wärme oder auch für Energieträger (z. B. Wasserstoff). Die saisonale oder temporale Überproduktion an Strom und Wärme aus erneuerbaren Energien zwingt dazu, eine urbane Speicherinfrastruktur aufzubauen, um eine grundlastfähige und bedarfsgerechte Lieferung zu realisieren. Hinzu kommt die Aufgabe das Treibhausgas Kohlendioxid aus der Atmosphäre zu reduzieren und unterirdisch dauerhaft zu lagern. Auch hier werden Speichertechnologien und ‐räume benötigt. Die nachhaltige energetische Nutzung des unterirdischen Raumes ist geeignet, entscheidende Beiträge zu einer zukünftigen Energiewirtschaft ohne fossile Brennstoffe zu leisten. Diese große interdisziplinäre Aufgabe erfordert die Zusammenarbeit vieler Fach‐, und Forschungseinrichtungen, die im Raum Berlin‐ Brandenburg vorhanden sind und in einer regionalen Forschungsallianz gebündelt werden sollen. Für die Region Berlin‐Brandenburg ergibt sich daraus die Chance, eine Schlüsselrolle in der Grundlagen‐ und angewandter Forschung zur Transformation des Energiesystems zu übernehmen und weltweit als Vorbild zu dienen. Im vorliegenden Papier werden die Formen einer nachhaltigen Geoenergienutzung, das geologische Potenzial der Region Berlin Brandenburg und dessen bisherige geoenergetische Nutzung dargestellt. Aus diesem Wissen wird der Ist‐Zustand hinsichtlich des energiewirtschaftlichen Potenzials und der sich daraus ergebenden Nutzungsoptionen abgeleitet, um darauf aufbauend Maßnahmen darzustellen, mit denen spürbare Beiträge zur Dekarbonisierung erreicht werden können. Daraus ergeben sich Handlungsempfehlungen für die Region, verbunden mit einem möglichen Beitrag der GEB² zum Risikomanagement, Investitionen in Schlüsseltechnologien, der Aus‐ und Weiterbildung, sowie der Akzeptanzerhöhung für geoenergetische Projekte. T2 - Gründungsveranstaltung der GeoEnergie Allianz Berlin Brandenburg CY - Berlin, Germany DA - 24.11.2023 KW - Geoenergie KW - Geothermie KW - Nachhaltigkeit PY - 2023 SP - 1 EP - 18 CY - Berlin & Potsdam AN - OPUS4-58924 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Strassert, J.F.H. A1 - Köhler, T. A1 - Wienemann, T. H. G. A1 - Ikeda-Ohtsubo, W. A1 - Faivre, N. A1 - Franckenberg, S. A1 - Plarre, Rüdiger A1 - Radek, R. A1 - Brune, A. T1 - 'Candidatus ancillula trichonymphae', a novel lineage of endosymbiotic actinobacteria in termite gut flagellates of the genus trichonympha N2 - Termite gut flagellates are colonized by host-specific lineages of ectosymbiotic and endosymbiotic bacteria. Previous studies have shown that flagellates of the genus Trichonympha may harbour more than one type of symbiont. Using a comprehensive approach that combined cloning of SSU rRNA genes with fluorescence in situ hybridization and electron microscopy, we investigated the phylogeny and subcellular locations of the symbionts in a variety of Trichonympha species from different termites. The flagellates in Trichonympha Cluster I were the only species associated with 'Endomicrobia', which were located in the posterior part of the cell, confirming previous results. Trichonympha species of Cluster II from the termite genus Incisitermes (family Kalotermitidae) lacked 'Endomicrobia' and were associated with endosymbiotic Actinobacteria, which is highly unusual. The endosymbionts, for which we suggest the name 'Candidatus Ancillula trichonymphae', represent a novel, deep-branching lineage in the Micrococcineae that consists exclusively of clones from termite guts. They preferentially colonized the anterior part of the flagellate host and were highly abundant in all species of Trichonympha Cluster II except Trichonympha globulosa. Here, they were outnumbered by a Desulfovibrio species associated with the cytoplasmic lamellae at the anterior cell pole. Such symbionts are present in both Trichonympha clusters, but not in all species. Unlike the intracellular location reported for the Desulfovibrio symbionts of Trichonympha agilis (Cluster I), the Desulfovibrio symbionts of T. globulosa (Cluster II) were situated in deep invaginations of the plasma membrane that were clearly connected to the exterior of the host cell. PY - 2012 DO - https://doi.org/10.1111/1462-2920.12012 SN - 1462-2912 SN - 1462-2920 VL - 14 IS - 12 SP - 3259 EP - 3270 PB - Blackwell Science CY - Oxford AN - OPUS4-27566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -