Dokument-ID Dokumenttyp Autoren/innen Persönliche Herausgeber/innen Haupttitel Abstract Auflage Verlagsort Verlag Herausgeber (Institution) Erscheinungsjahr Titel des übergeordneten Werkes Jahrgang/Band ISBN Veranstaltung Veranstaltungsort Beginndatum der Veranstaltung Enddatum der Veranstaltung Ausgabe/Heft Erste Seite Letzte Seite URN DOI Lizenz Datum der Freischaltung OPUS4-22070 Zeitschriftenartikel Kupsch, Andreas; Lange, Axel; Hentschel, Manfred P.; Manke, I.; Kardjilov, N.; Arlt, Tobias; Grothausmann, R. Rekonstruktion limitierter CT-Messdatensätze von Brennstoffzellen mit Directt Die Aufklärung spezifischer Fragestellungen zur Funktionalität von PEM(polymer electrolyte membrane)- und DMFC(Direct Methanol)-Brennstoffzellen bedarf der 3D-Abbildung der spezifischen Komponenten mit unterschiedlichen Strahlungsarten: des Wassergehalts in den Flow Fields mit Neutronen, der Katalysator-Alterung in der MEA (membrane electrode assembly) mit Synchrotronstrahlung und der freien (reaktiven) Katalysator-Oberfläche von Nano-Partikeln mit TEM-Elektronen-Tomografie. Diese Messungen im Bereich der mm- bis nm-Skala unterliegen dabei erheblichen Restriktionen: einer ortsabhängigen Verschmierung der Neutronenradiogramme, Manipulatorinstabilitäten der Synchrotronmessungen sowie einer Kombination von Limited-View-Datensätzen, wenigen Projektionswinkeln und teilweiser Nichtdurchstrahlbarkeit in der Elektronen-CT. Die Vorteile eines fortentwickelten Directt-Algorithmus für die Bewältigung dieser Randbedingungen gegenüber gefilterten Rückprojektionen werden aufgezeigt. München Hanser Bundesanstalt für Materialforschung und -prüfung 2010 MP materials testing 52 10 676 683 2016-02-19 OPUS4-25833 Beitrag zu einem Tagungsband Kupsch, Andreas; Lange, Axel; Hentschel, Manfred P.; Grothausmann, R.; Arlt, Tobias; Manke, I. High quality reconstruction of insufficient tomographic data by a new iterative procedure In order to demonstrate the challenging tasks in current R&D applications in the field of renewable energy sources experimental neutron and electron tomographic data sets of PEM fuel cell components are processed by an advanced version of the DIRECTT algorithm. The neutron measurements of the water distribution suffer from several intrinsic limitations such as massive position dependent focal smearing due to the large primary neutron beam aperture. Electron (TEM) tomography allows characterisation of nanometre sized catalyst particles but is hampered by the following restrictions: partial opacity, a limited sector of projections (missing wedge), very few projections, samples exceeding the detector size (region of interest) and improper angular alignment. Beyond the capabilities of other algorithms DIRECTT proves to overcome these essential reconstruction problems, in comparison to FBP and SIRT. Nevertheless, careful data pre-processing is an inevitable requirement in order to fully exploit the algorithm's potentials. 2012 18th WCNDT - World conference on nondestructive testing (Proceedings) 978-0-620-52872-6 18th WCNDT - World conference on nondestructive testing Durban, South Africa 2012-04-16 2012-04-20 1 8(?) 2016-02-19 OPUS4-56164 Zeitschriftenartikel Van Tran, K.; Woracek, R.; Kardjilov, N.; Markötter, Henning; Abou-Ras, D.; Puplampu, S.; Förster, C.; Penumadu, D.; Dahlberg, C. F. O.; Banhart, J.; Manke, I. Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale. Elsevier Ltd. 2022 Materials & Design 222 111037 urn:nbn:de:kobv:b43-561649 10.1016/j.matdes.2022.111037 https://creativecommons.org/licenses/by/4.0/deed.de 2022-11-03 OPUS4-31972 Beitrag zu einem Tagungsband Lange, Axel; Hentschel, Manfred P.; Kupsch, Andreas; Jaenisch, Gerd-Rüdiger; Kardjilov, N.; Tötzke, C.; Markötter, H.; Hilger, A.; Manke, I. X-ray compton tomography 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. Brno Brno University of Technology 2014 ECNDT 2014 Proceedings 978-80-214-5018-9 ECNDT 2014 - 11th European Conference on Non-Destructive Testing Prague, Czech Republic 06.10.2014 10.10.2014 1 9 2016-02-20 OPUS4-31084 Zeitschriftenartikel Griesche, Axel; Dabah, Eitan; Kardjilov, N.; Hilger, A.; Manke, I.; Kannengießer, Thomas Imaging of hydrogen in steels using neutrons We investigated the hydrogen distribution spatially and temporally in technical iron at room temperature. Samples were charged electrochemically and subsequently analysed by means of neutron radiography and tomography. The radiographic images allowed for a time-resolved analysis of hydrogen fluxes. The three-dimensional distribution of hydrogen measured by neutron tomography delivered valuable information for the damage analysis of hydrogen-induced cracks. For the first time hydrogen concentration gradients inside the material could be detect directly together with the cracks. The neutron radiography and tomography results were gained at the Research Reactor BER II of the HZB in Berlin. München Carl Hanser Deutsche Gesellschaft für Materialkunde 2014 International journal of materials research 105 7 640 644 10.3139/146.111043 2016-02-20 OPUS4-31068 Zeitschriftenartikel Griesche, Axel; Dabah, Eitan; Kannengießer, Thomas; Kardjilov, N.; Hilger, A.; Manke, I. Three-dimensional imaging of hydrogen blister in iron with neutron tomography We investigated hydrogen embrittlement and blistering in electrochemically hydrogen-charged technical iron samples at room temperature. Hydrogen-stimulated cracks and blisters and the corresponding hydrogen distributions were observed by neutron tomography. Cold neutrons were provided by the research reactor BER II to picture the sample with a spatial resolution in the reconstructed three-dimensional model of ~25 µm. We made the unique observation that cracks were filled with molecular hydrogen and that cracks were surrounded by a 50 µm wide zone with a high hydrogen concentration. The zone contains up to ten times more hydrogen than the bulk material. The hydrogen enriched zone can be ascribed to a region of increased local defect density. Hydrogen also accumulated at the sample surface having the highest concentration at blistered areas. The surfaces of the brittle fractured cracks showed micropores visualized by scanning electron microscopy. The micropores were located at grain boundaries and were surrounded by stress fields detected by electron backscattered diffraction. The cracks clearly originated from the micropores. Kidlington Elsevier Science 2014 Acta materialia 78 14 22 10.1016/j.actamat.2014.06.034 2016-02-20 OPUS4-34963 Zeitschriftenartikel Kupsch, Andreas; Lange, Axel; Hentschel, Manfred P.; Jaenisch, Gerd-Rüdiger; Kardjilov, N.; Tötzke, C.; Markötter, H.; Hilger, A.; Manke, I. X-ray compton line scan tomography 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. München Hanser 2015 Materials testing 57 11-12 985 991 10.3139/120.110799 2016-02-20 OPUS4-56910 Zeitschriftenartikel Tran, K. V.; Woracek, R.; Kardjilov, N.; Markötter, Henning; Abou-Ras, D.; Puplampu, S.; Förster, C.; Penumadu, D.; Dahlberg, C. F. O.; Banhart, J.; Manke, I. Torsion of a rectangular bar: Complex phase distribution in 304L steel revealed by neutron tomography Metastable austenitic stainless steel (304L) samples with a rectangular cross-section were plastically deformed in torsion during which they experienced multiaxial stresses that led to a complex martensitic phase distribution owing to the transformation induced plasticity effect. A three-dimensional characterization of the phase distributions in these cm-sized samples was carried out by wavelength-selective neutron tomography. It was found that quantitatively correct results are obtained as long as the samples do not exhibit any considerable preferential grain orientation. Optical microscopy, electron backscatter diffraction, and finite element modeling were used to verify and explain the results obtained by neutron tomography. Altogether, neutron tomography was shown to extend the range of microstructure characterization methods towards the meso- and macroscale. Elsevier Ltd. 2022 Materials & Design 222 1 13 urn:nbn:de:kobv:b43-569101 10.1016/j.matdes.2022.111037 https://creativecommons.org/licenses/by/4.0/deed.de 2023-01-30