TY - GEN A1 - Treimer, W. A1 - Feye–Treimer, U. A1 - Radke, C. A1 - Hilger, A. A1 - Neumann, O. A1 - Manke, I. A1 - Haibel, A. A1 - Rack, A. A1 - Riesemeier, Heinrich T1 - Investigations of mamma biopsies by means of µ-tomography T2 - BESSY highlights - annual report 2004 PY - 2005 UR - http://www.helmholtz-berlin.de/media/media/oea/web/pr_webseite/druckschriften/berichte/bessy/annualreport2004.pdf#page=452 SN - 0179-4159 SP - 452 EP - 453 PB - Berliner Elektronenspeicherring-Gesellschaft für Synchrotronstrahlung CY - Berlin AN - OPUS4-7383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zabler, S. A1 - Rueda, A. A1 - Rack, A. A1 - Riesemeier, Heinrich A1 - Zaslansky, P. A1 - Manke, I. A1 - Garcia-Moreno, F. A1 - Banhart, J. T1 - Coarsening of grain-refined semi-solid Al-Ge32 alloy: X-ray microtomography and in situ radiography JF - Acta materialia KW - Microtomography KW - Radiography KW - 2D/3D imageanalysis KW - Technical binary alloys KW - LSW PY - 2007 DO - https://doi.org/10.1016/j.actamat.2007.05.028 SN - 1359-6454 SN - 1873-2453 VL - 55 IS - 15 SP - 5045 EP - 5055 PB - Elsevier Science CY - Kidlington AN - OPUS4-20583 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zabler, S. A1 - Rack, A. A1 - Manke, I. A1 - Thermann, K. A1 - Tiedemann, J. A1 - Harthill, N. A1 - Riesemeier, Heinrich T1 - High-resolution tomography of cracks, voids and micro-structure in greywacke and limestone JF - Journal of structural geology N2 - Rocks are commonly very heterogeneous materials. Randomly distributed micro-flaws inside the rock are believed to initiate tensile cracks from which shear fractures develop and coalescence through en echelon interactions leads to fracture. In this paper, we describe the results of applying high-resolution X-ray tomography to samples of greywacke and limestone experimentally deformed under unconfined axial shortening at various loads equivalent to different fractions of the sample strength. Mineral grains, pores, micro-cracks and other voids were imaged with a resolution of 10 µm. 3D image analysis enabled us to monitor the initial state of the samples and the changes in them due to compression. Crack morphology is characterized and compared to the micro-structure of the sample before and after deformation. In the greywacke, formation of a macro-crack ~10° oblique to the stress direction is observed. It initiated in fine intergranular material at the top tip of the sample and is composed of tensile fractures connected by wing cracks. None of the voids defined in the initial state fractured, and the crack is interpreted to have started either as a micro-crack which was smaller than the resolution of the tomography, or, as a completely new crack. In the limestone, cracks are observed to initiate in features that are too small to be imaged by the tomography, or also in newly created cracks. KW - Rock porosity KW - Crack formation KW - X-ray imaging KW - Micro-tomography KW - 3D image analysis PY - 2008 DO - https://doi.org/10.1016/j.jsg.2008.03.002 SN - 0191-8141 SN - 1873-1201 VL - 30 IS - 7 SP - 876 EP - 887 PB - Pergamon Press CY - Oxford AN - OPUS4-18566 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartnig, C. A1 - Kuhn, R. A1 - Krüger, P. A1 - Manke, I. A1 - Kardjilov, N. A1 - Goebbels, Jürgen A1 - Müller, Bernd R. A1 - Riesemeier, Heinrich T1 - Wassermanagement in Brennstoffzellen - die Bedeutung von hochauflösenden zerstörungsfreien Untersuchungsmethoden JF - MP materials testing N2 - Ein effektives Wassermanagement ist ein wichtiger Aspekt in der Entwicklung von Brennstoffzellen hinsichtlich Langzeitstabilität und Optimierung der Leistungsfähigkeit. Eine zentrale Rolle spielt dabei die Gasdiffusionslage, die für die gleichmäßige Verteilung der Reaktionsgase auf die elektrochemisch aktive Schicht (Katalysator) sorgen soll. In diesem Beitrag werden gemeinsame Forschungsaktivitäten des Helmholtz-Zentrums Berlin für Materialien und Energie (Entwicklung bildgebender Verfahren) sowie des Zentrums für Sonnenenergie- und Wasserstoff-Forschung (ZSW, Entwicklung von Brennstoffzellen) vorgestellt. Im Rahmen dieser Kooperation werden die Entstehung, die Verteilung und der Transport von flüssigem Wasser, kurz das Wassermanagement, unter Betriebsbedingungen untersucht. Mittels Synchrotronradiografie und -tomografie werden kleinste Wassercluster in der Gasdiffusionslage detektiert. Die gewonnenen Erkenntnisse dienen der Modifikation und einer gezielten Auswahl der eingesetzten Materialien. KW - Synchrotronstrahlung KW - Brennstoffzellen KW - Materialcharakterisierung KW - Zerstörungsfrei PY - 2008 SN - 0025-5300 VL - 50 IS - 10 SP - 609 EP - 614 PB - Hanser CY - München AN - OPUS4-18656 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hartnig, C. A1 - Manke, I. A1 - Schloesser, J. A1 - Krüger, P. A1 - Kuhn, R. A1 - Riesemeier, Heinrich A1 - Wippermann, K. A1 - Banhart, J. T1 - High resolution synchrotron X-ray investigation of carbon dioxide evolution in operating direct methanol fuel cells JF - Electrochemistry communications N2 - The carbon dioxide evolution and bubble formation in an operating fuel has been studied by means of synchrotron X-ray radiography. Two different observation directions have been chosen: a through-plane insight has been employed to track the formation of bubbles starting at the corner of the lands of the flow field; a depth profile of the carbon dioxide evolution has been derived from cross sectional studies describing an affected area of up to 100 µm. The dynamics of the bubble formation and detachment of the bubbles from the position of formation is strongly correlated with the current density. Cracks and breaks in the catalyst layer which result from the preparation process are visible under operating conditions and a possible swelling of the catalyst layer does not reach a complete vanishing of the cracks. KW - DMFC KW - Carbon dioxide evolution KW - Synchrotron radiography KW - In situ study KW - Cross section KW - Through-plane PY - 2009 DO - https://doi.org/10.1016/j.elecom.2009.05.047 SN - 1388-2481 VL - 11 IS - 8 SP - 1559 EP - 1562 PB - Elsevier CY - Amsterdam AN - OPUS4-20577 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manke, I. A1 - Hartnig, C. A1 - Kardjilov, N. A1 - Riesemeier, Heinrich A1 - Goebbels, Jürgen A1 - Kuhn, R. A1 - Krüger, P. A1 - Banhart, J. T1 - In situ synchrotron X-ray radiography investigations of water transport in PEM fuel cells JF - Fuel Cells N2 - Water transport in an operating PEM fuel cell was investigated with synchrotron X-ray radiography with a spatial resolution of 3 µm and a temporal resolution of 5 s. This method allows for the detection of water accumulations with less than 10 µm diameter. We demonstrate that synchrotron X-ray imaging can dramatically expand the possibilities of imaging with high spatial and time resolution, especially as a complement to neutron radiography. Water transport processes from the first appearance of small water accumulations in the gas diffusion layer to their transport into the channel system were analysed in situ. Correlations between local effects such as water formation and operating conditions of the whole system, e.g. power variations, were found. A recently described eruptive water transport mechanism is analysed in detail. KW - Fuel cell KW - Gas diffusion layer KW - Imaging KW - Synchrotron KW - X-ray radiography KW - Two-phase flow KW - Water transport PY - 2010 DO - https://doi.org/10.1002/fuce.200800123 SN - 1615-6846 SN - 1615-6854 VL - 10 IS - 1 SP - 26 EP - 34 PB - Wiley-VCH CY - Weinheim AN - OPUS4-22730 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maier, W. A1 - Arlt, Tobias A1 - Wannek, C. A1 - Manke, I. A1 - Riesemeier, Heinrich A1 - Krüger, P. A1 - Scholta, J. A1 - Lehnert, W. A1 - Banhart, J. A1 - Stolten, D. T1 - In-situ synchrotron X-ray radiography on high temperature polymer electrolyte fuel cells JF - Electrochemistry communications N2 - In contrast to classical low temperature polymer electrolyte fuel cells (LT-PEFCs), the membrane conductivity in high temperature polymer electrolyte fuel cells (HT-PEFCs) (operating temperature ~ 160 °C) is based on proton transport within phosphorus-oxygen acids at different levels of hydration, orthophosphoric acid (H3PO4) being the simplest example. We present for the first time in-situ synchrotron X-ray radiography measurements applied to a HT-PEFC to gain insight into the local composition of the membrane electrode assembly (MEA) under dynamic operating conditions. Transmission changes during the radiographic measurements exhibit a clear influence of the formation of product water on the membrane composition. KW - HT-PEFC KW - Synchrotron x-ray radiography KW - Membrane electrode assembly (MEA) KW - Phosphoric acid PY - 2010 DO - https://doi.org/10.1016/j.elecom.2010.08.002 SN - 1388-2481 VL - 12 IS - 10 SP - 1436 EP - 1438 PB - Elsevier CY - Amsterdam AN - OPUS4-23962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krüger, P. A1 - Markötter, H. A1 - Klages, M. A1 - Haußmann, J. A1 - Arlt, Tobias A1 - Riesemeier, Heinrich A1 - Hartnig, C. A1 - Banhart, J. A1 - Manke, I. A1 - Scholta, J. T1 - Dreidimensionale Untersuchung der Wasserverteilung in einer Miniatur-PEM-Brennstoffzelle JF - MP materials testing KW - Resolution neutron-radiography KW - Local current distribution KW - Cells KW - Quantification PY - 2010 SN - 0025-5300 VL - 52 IS - 10 SP - 712 EP - 717 PB - Hanser CY - München AN - OPUS4-23044 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arlt, Tobias A1 - Manke, I. A1 - Wippermann, K. A1 - Schröder, A. A1 - Mergel, J. A1 - Riesemeier, Heinrich A1 - Banhart, J. T1 - Röntgen-Kanten-Tomografie und -Radiografie zur Untersuchung von Alterungseffekten in Brennstoffzellenmaterialien JF - MP materials testing KW - Resolution neutron-radiography KW - Local current distribution KW - Water transport KW - Carbon-dioxide KW - Methanol KW - Platinum KW - Oxidation PY - 2010 SN - 0025-5300 VL - 52 IS - 10 SP - 692 EP - 697 PB - Hanser CY - München AN - OPUS4-23045 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, H. A1 - Manke, I. A1 - Hartnig, C. A1 - Krüger, P. A1 - Wippermann, K. A1 - Arlt, Tobias A1 - Choinka, G. A1 - Riesemeier, Heinrich A1 - Banhart, J. T1 - Hochauflösende Synchrotron-Radiografie JF - MP materials testing KW - PEM Fuel-cells KW - Local current distribution KW - Neutron imaging technique KW - Water transport PY - 2010 SN - 0025-5300 VL - 52 IS - 10 SP - 698 EP - 704 PB - Hanser CY - München AN - OPUS4-23046 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -