TY - CONF A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Kupsch, Andreas A1 - Jaenisch, Gerd-Rüdiger A1 - Kardjilov, N. A1 - Tötzke, C. A1 - Markötter, H. A1 - Hilger, A. A1 - Manke, I. T1 - X-ray compton tomography N2 - The potentials of incoherent X-ray Scattering (Compton) tomography are investigated. Imaging materials of very different density or atomic number at once is a perpetual challenge for X-ray tomography or radiography, in general. In a basic laboratory set-up for simultaneous perpendicular Compton Scattering and direct beam attenuation tomographic scans are conducted by single channel photon counting. This results in asymmetric distortions of the projection profiles of the scattering CT-data set. ln a first approach corrections of Compton scattering data by taking advantage of rotational symmetry yield tomograms without major geometric artefacts. A cylindrical sample composed of PE, PA, PVC, glass and wood demonstrates similar Compton contrast for all the substances, while the conventional absorption tomogram only reveals the two high order materials. Compärison to neutron tomography reveals astonishing similarities except for the glass component (without hydrogen). Therefore, Compton CT bears the potential to replace neutron tomography, which requires much more efforts. T2 - ECNDT 2014 - 11th European Conference on Non-Destructive Testing CY - Prague, Czech Republic DA - 06.10.2014 KW - X-ray compton scattering KW - Computed tomography KW - Neutron tomography PY - 2014 SN - 978-80-214-5018-9 SP - 1 EP - 9 PB - Brno University of Technology CY - Brno AN - OPUS4-31972 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Jaenisch, Gerd-Rüdiger A1 - Kardjilov, N. A1 - Tötzke, C. A1 - Markötter, H. A1 - Hilger, A. A1 - Manke, I. T1 - X-ray compton line scan tomography N2 - The potentials of incoherent X-ray scattering (Compton) computed tomography (CT) are investigated. The imaging of materials of very different atomic number or density at once is generally a perpetual challenge for X-ray tomography or radiography. In a basic laboratory set-up for simultaneous perpendicular Compton scattering and direct beam attenuation tomography are conducted by single channel photon counting line scans. This results in asymmetric distortions of the projection profiles of the scattering CT data set. In a first approach, corrections of Compton scattering data by taking advantage of rotational symmetry yield tomograms without major geometric artefacts. A cylindrical sample composed of PE, PA, PVC, glass and wood demonstrates similar Compton contrast for all the substances, while the conventional absorption tomogram only reveals the two high order materials. Comparison to neutron tomography reveals astonishing similarities except for the glass component (without hydrogen). Therefore, Compton CT offers the potential to replace neutron tomography, which requires much more efforts. KW - X-ray compton scattering KW - Computed tomography KW - Neutron tomography PY - 2015 U6 - https://doi.org/10.3139/120.110799 SN - 0025-5300 VL - 57 IS - 11-12 SP - 985 EP - 991 PB - Hanser CY - München AN - OPUS4-34963 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, H. A1 - Alink, R. A1 - Haußmann, J. A1 - Dittmann, K. A1 - Arlt, Tobias A1 - Wieder, F. A1 - Tötzke, C. A1 - Klages, M. A1 - Reiter, C. A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Gerteisen, D. A1 - Banhart, J. A1 - Manke, I. T1 - Visualization of the water distribution in perforated gas diffusion layers by means of synchrotron X-ray radiography N2 - Perforated gas diffusion layers (GDLs) of polymer electrolyte membrane fuel cells (PEMFCs) were investigated by means of in-situ synchrotron X-ray radiography during operation. We found a strong influence of perforations on the water distribution and transport in the investigated Toray TGP-H-090 GDL. The water occurs mainly around the perforations, while the holes themselves show varying water distributions. Some remain dry, while most of them fill up with liquid water after a certain period or might serve as drainage volume for effective water transport. KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Radiography KW - Synchrotron KW - X-ray imaging KW - Perforated gas diffusion layer (GDL) KW - Water transport PY - 2012 U6 - https://doi.org/10.1016/j.ijhydene.2012.01.141 SN - 0360-3199 VL - 37 IS - 9 SP - 7757 EP - 7761 PB - Elsevier CY - Oxford AN - OPUS4-26434 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arlt, Tobias A1 - Grothausmann, R. A1 - Manke, I. A1 - Markötter, H. A1 - Hilger, A. A1 - Kardjilov, N. A1 - Tötzke, C. A1 - Banhart, J. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Krüger, P. A1 - Haußmann, J. A1 - Hartnig, C. A1 - Wippermann, K. T1 - Tomografische Methoden für die Brennstoffzellenforschung N2 - Aufgrund des hohen Wirkungsgrades und der vielfältigen Einsatzmöglichkeiten können Brennstoffzellen einen wichtigen Beitrag zur zukünftigen Energieversorgung leisten. Für die Optimierung der Brennstoffzellentechnik ist es erforderlich, die während des Zellbetriebs ablaufenden Prozesse zu verstehen und exakt zu charakterisieren. Ein ausbalanciertes Wassermanagement ist die Grundlage für die optimale Leistungsfähigkeit einer wasserstoffbetriebenen Zelle. Das während des Betriebs entstehende Wasser muss die Membran ausreichend befeuchten, um deren Protonenleitfähigkeit aufrechtzuerhalten. Andererseits behindern zu große Wasseransammlungen in der Zelle die Gaszufuhr durch die porösen Materialien sowie in den Kanälen der Gasverteilerstrukturen. Alterungsphänomene einzelner Zellkomponenten können die Verteilung der Wasseransammlungen und somit das Wassermanagement empfindlich stören und so die Leistungsfähigkeit der Brennstoffzelle herabsetzen. Zur Analyse der Wasserverteilung werden zerstörungsfreie, bildgebende Methoden, wie die Ex-situ-Neutronentomografie und die In-situ-Synchrotronradiografie, eingesetzt. Diese Methoden können während des Brennstoffzellenbetriebs mit weiteren Messverfahren, beispielsweise der ortsaufgelösten Stromdichtemessung, kombiniert werden. Auf diese Weise werden einzelne Komponenten, wie zum Beispiel die Gasdiffusionsschichten, charakterisiert. KW - Computertomographie KW - Elektronentomographie KW - Neutronentomographie KW - Brennstoffzelle KW - Stromdichtemessung KW - Wassermanagement PY - 2013 U6 - https://doi.org/10.3139/120.110429 SN - 0025-5300 VL - 55 IS - 3 SP - 207 EP - 213 PB - Hanser CY - München AN - OPUS4-27950 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tötzke, C. A1 - Gaiselmann, G. A1 - Osenberg, M. A1 - Bohner, J. A1 - Arlt, Tobias A1 - Markötter, H. A1 - Hilger, A. A1 - Wieder, F. A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Hentschel, Manfred P. A1 - Banhart, J. A1 - Schmidt, V. A1 - Lehnert, W. A1 - Manke, I. T1 - Three-dimensional study of compressed gas diffusion layers using synchrotron X-ray imaging N2 - We present a synchrotron X-ray tomographic study on the morphology of carbon fiber-based gas diffusion layer (GDL) material under compression. A dedicated compression device is used to provide well-defined compression conditions. A flat compression punch is employed to study the fiber geometry at different degrees of compression. Transport relevant geometrical parameters such as porosity, pore size and tortuosity distributions are calculated. The geometric properties notably change upon compression which has direct impact on transport conditions for gas and fluid flow. The availability of broad 3D paths, which are most important for the transport of liquid water from the catalyst layer through the GDL, is markedly reduced after compression. In a second experiment, we study the influence of the channel-land-pattern of the flow-field on shape and microstructure of the GDL. A flow-field compression punch is employed to reproduce the inhomogeneous compression conditions found during fuel cell assembly. While homogenously compressed underneath the land the GDL is much less and inhomogeneously compressed under the channel. The GDL material extends far into the channel volume where it can considerably influence gas and fluid flow. Loose fiber endings penetrate deeply into the channel and form obstacles for the discharge of liquid water droplets. KW - Synchrotron X-ray tomography KW - Gas diffusion layer (GDL) KW - Microstructure KW - Water transport path KW - Pore size analysis KW - Geometrical tortuosity PY - 2014 U6 - https://doi.org/10.1016/j.jpowsour.2013.12.062 SN - 0378-7753 VL - 253 SP - 123 EP - 131 PB - Elsevier CY - Amsterdam [u.a.] AN - OPUS4-29979 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Manke, I. A1 - Kardjilov, N. A1 - Schäfer, R. A1 - Hilger, A. A1 - Grothausmann, R. A1 - Strobl, M. A1 - Dawson, M. A1 - Grünzweig, C. A1 - Tötzke, C. A1 - David, C. A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Hentschel, Manfred P. A1 - Banhart, J. T1 - Three-dimensional imaging of magnetic domains with neutron grating interferometry N2 - This paper gives a brief overview on3D imaging of magnetic domains with shearing grating neutron tomography. We investigated the three-dimensional distribution of magnetic domain walls in the bulk of a wedge-shaped FeSi single crystal. The width of the magnetic domains wasanalyzed at different locations within the crystal. Magnetic domains close to the tip of the wedge are much smaller than in the bulk. Furthermore, the three-dimensional shape of individual domains wasinvestigated. We discuss prospects and limitations of the applied measurement technique. KW - Neutron imaging KW - Tomography KW - Magnetic domains KW - Grating interferometry KW - Darkfield imaging KW - Shearing gratings KW - Talbot-Lau KW - Three-dimensional data quantification KW - Tomographic reconstruction PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-341919 SN - 1875-3892 VL - 69 SP - 404 EP - 412 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-34191 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Tötzke, C. A1 - Kupsch, Andreas A1 - Müller, Bernd R. A1 - Manke, I. A1 - Hilger, A. A1 - Arlt, Tobias A1 - Markötter, H. A1 - Wieder, F. A1 - Bohner, J. A1 - Schmidt, V. A1 - Banhart, J. T1 - Synchrotron tomographic study on the inhomogeneous compression of gas diffusion layers in fuel cells T2 - 10th Symposium on Fuel Cell and Battery Modelling and Experimental Validation - ModVal 10 CY - Bad Boll, Germany DA - 2013-03-19 PY - 2013 AN - OPUS4-28078 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Bernd R. A1 - Tötzke, C. A1 - Manke, I. A1 - Arlt, Tobias A1 - Markötter, H. A1 - Hilger, A. A1 - Kardjilov, N. A1 - Krüger, P. A1 - Scholta, J. T1 - Non-Destructive Analysis of Water and Media Distribution in Fuel Cells by Means of Neutron and Synchrotron X-ray Imaging T2 - 220th ECS Meeting and Electrochemical Energy Summit CY - Boston, MA, USA DA - 2011-10-09 PY - 2011 AN - OPUS4-25381 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Arlt, Tobias A1 - Manke, I. A1 - Wippermann, K. A1 - Tötzke, C. A1 - Markötter, H. A1 - Riesemeier, Heinrich A1 - Mergel, J. A1 - Banhart, J. T1 - Investigation of the three-dimensional ruthenium distribution in fresh and aged membrane electrode assemblies with synchrotron X-ray absorption edge tomography N2 - Synchrotron X-ray absorption edge imaging was used to investigate the ruthenium distribution in both fresh and aged Pt/Ru-based membrane electrode assemblies (MEA) of direct methanol fuel cells. MEAs aged in different ways were analyzed: artificially aged by MeOH depletion and aged for 1700 h in an operating fuel cell stack. An element sensitive tomographic technique – differential X-ray absorption edge tomography – was applied allowing for a 3D-visualization of the ruthenium distribution within the MEA. We found a markedly changed Ru distribution after aging which is correlated to the GDL structure, the flow field geometry, and CO2 transport in the methanol solution. KW - Edge tomography KW - Ruthenium distribution KW - Direct methanol fuel cells KW - Synchrotron X-ray KW - PtRu corrosion PY - 2011 U6 - https://doi.org/10.1016/j.elecom.2011.05.013 SN - 1388-2481 VL - 13 IS - 8 SP - 826 EP - 829 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-25243 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, H. A1 - Haußmann, J. A1 - Alink, R. A1 - Dittmann, K. A1 - Tötzke, C. A1 - Krüger, P. A1 - Klages, M. A1 - Arlt, Tobias A1 - Müller, Bernd R. A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Gerteisen, D. A1 - Manke, I. A1 - Banhart, J. T1 - Investigation of fuel cell materials and liquid water transport by means of synchrotron imaging N2 - Synchrotron imaging allows addressing various important issues in fuel cell research, for example water distribution and transport. The water distribution in polymer electrolyte membrane fuel cells (PEMFCs) was observed quasi in-situ directly after operation by means of synchrotron tomography. The 3D data set was compared with the tomogram of a dry cell in order to separate the water distribution from cell materials. Engineered transport pathways realized by perforating holes through the gas diffusion layer (GDL) are a recent approach to optimize water transport and cell performance. For some parameter sets a cell performance increase and an improvement of stabilization have already been proven. We present high resolution investigations of the water distribution in perforated GDLs of operating PEMFCs by means of in-situ synchrotron radiography. The surrounding areas of the holes exhibited a distinct hydrophilic character. KW - Gas-diffusion layers KW - Resolution neutron-radiography KW - X-ray radiography KW - Visualization KW - PEMFC PY - 2013 U6 - https://doi.org/10.1149/04529.0195ecst SN - 1938-6737 SN - 1938-5862 VL - 45 IS - 29 SP - 195 EP - 202 CY - Pennington, NJ, USA AN - OPUS4-30545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -