TY - JOUR A1 - Markötter, H. A1 - Haußmann, J. A1 - Alink, R. A1 - Tötzke, C. A1 - Arlt, Tobias A1 - Klages, M. A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Gerteisen, D. A1 - Banhart, J. A1 - Manke, I. T1 - Influence of cracks in the microporous layer on the water distribution in a PEM fuel cell investigated by synchrotron radiography N2 - Water evolution in the gas diffusion layer of a polymer electrolyte membrane fuel cell was visualized in situ by means of synchrotron X-ray radiography. Cracks in the microporous layer were identified as start points of efficient liquid water transfer paths through the gas diffusion layer. Quantitative analysis of the water flow rate through those arbitrarily distributed cracks into the gas channel revealed that they have a strong influence on the overall liquid water transport. This could find entry into future material design and simulation. KW - Polymer electrolyte membrane fuel cell (PEMFC) KW - Radiography KW - Synchrotron X-ray imaging KW - Microporous layer (MPL) KW - Water transport KW - Liquid water flow rate PY - 2013 U6 - https://doi.org/10.1016/j.elecom.2013.04.006 SN - 1388-2481 VL - 34 SP - 22 EP - 24 PB - Elsevier CY - Amsterdam AN - OPUS4-30548 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - 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 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 - 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 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 - TY - CONF 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 - Compton-CT als Alternative zur Neutronentomographie? N2 - Als Alternative zur Neutronentomographie wird das Potenzial der Computertomographie (CT) mit inkohärenter Röntgen-Streustrahlung (Compton-Streuung) untersucht. Die gleichzeitige Abbildung von Materialien sehr unterschiedlicher Dichten (Ordnungszahlen) ist eine wiederkehrende Herausforderung für die Radiologie und die Computertomographie mit Röntgenstrahlung. Die Messungen ergeben asymmetrische Projektionsprofile für Sinogramme der Streuintensität. Am Beispiel verschiedener Polymere (Polyethylen, Polyamid, PVC), Glas und Holz wird in den Tomogrammen ein hochaufgelöster 'Comptonkontrast' vergleichbarer Dynamik erreicht, während der simultan gemessene 'Absorptionskontrast' ausschließlich die starken Absorber (Glas und PVC) zeigt. Der Vergleich mit ähnlich auflösender Neutronentomographie zeigt ähnliche Kontraste und eröffnet mithin die Möglichkeit, diese künftig durch Compton-Tomographie im Labormaßstab zu ersetzen. T2 - DACH-Jahrestagung 2015 CY - Salzburg, Austria DA - 11.05.2015 KW - Comptonstreuung KW - Computertomographie KW - Neutronentomographie PY - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-342894 SN - 978-3-940283-68-9 IS - DGZfP BB 152 SP - Mo.3.A.2, 1 EP - 10 AN - OPUS4-34289 LA - deu 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 - Alrwashdeh, S. S. A1 - Markötter, H. A1 - Haußmann, J. A1 - Hilger, A. A1 - Klages, M. A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Riesemeier, Heinrich A1 - Scholta, J. A1 - Manke, I. T1 - Investigation of water transport in newly developed micro porous layers for polymer electrolyte membrane fuel cells N2 - In this investigation, synchrotron X-ray imaging was used to investigate the water distribution inside newly developed gas diffusion media in polymer electrolyte membrane fuel cells. In-situ radiography was used to reveal the relationship between the structure of the microporous layer (MPL) and the water flow in a newly developed MPL equipped with randomly arranged holes. A strong influence of these holes on the overall water transport was found. This contribution provides a brief overview to some of our recent activities on this research field. KW - Polymer electrolyte membrane fuel cell KW - Microporous layer KW - Water distribution KW - Radiography KW - Synchrotron X-ray imaging PY - 2017 U6 - https://doi.org/10.9729/AM.2017.47.3.101 SN - 2287-4445 SN - 2287-5123 VL - 47 IS - 3 SP - 101 EP - 104 AN - OPUS4-43356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Göbel, M. A1 - Kirsch, S. A1 - Schwarze, L: A1 - Schmidt, L. A1 - Scholz, H. A1 - Haußmann, J. A1 - Klages, M. A1 - Scholta, J. A1 - Markötter, H. A1 - Alrwashdeh, S. A1 - Manke, I. A1 - Müller, Bernd R. T1 - Transient limiting current measurements for characterization of gas diffusion layers N2 - The water management in proton exchange membrane fuel cells (PEMFC) is strongly influenced by the design of the gas diffusion layers (GDL). Limiting current measurements in small-scale cells operating at high stoichiometries are useful to determine the oxygen transport resistance. The oxygen transport resistance increases, once water condenses inside the GDL. In this study a new electrochemical method for voltage loss estimation of GDL induced oxygen transport losses are presented. This new method, referred to as “transient limiting current” (TLC), is compared with the literature method. TLC allows a direct estimation of oxygen transport resistance at an arbitrarily conditioned state. This study also presents a case study of liquid water visualization of a PEM fuel cell with varying GDLs types. With the help of quasi in-situ synchrotron X-ray computed tomography and time resolved radiography measurements we investigate appearance and distribution of liquid water inside the GDLs under limiting current conditions. KW - In-situ characterization of GDLs KW - In-situ synchrotron X-ray computed tomography KW - In-situ synchrotron X-ray radiography KW - BAMline PY - 2018 U6 - https://doi.org/10.1016/j.jpowsour.2018.09.003 SN - 0378-7753 SN - 1873-2755 VL - 402 SP - 237 EP - 245 PB - Elsevier B.V. AN - OPUS4-46552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -