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 DO - 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 - TY - JOUR A1 - Wirth, Cynthia A1 - Müller, Ralf A1 - Günster, Jens A1 - Mühler, T. A1 - Görke, R. A1 - Heinrich, J.G. T1 - Submicrometer silica spheres generated by laser fuming N2 - The production of agglomerate-free SiO2 particles exhibiting a monomodal distribution of particle sizes of around 300 nm by means of direct laser fuming of micrometric SiO2 powders has been successfully demonstrated. With a 12 kW cw CO2 laser system, a production rate of up to 1 kilogram powder per hour was achieved. Almost ideal spherical amorphous SiO2 particles in a broad particle size distribution between 10 nm and several 100 nm (d50 ≈ 300 nm) were synthesized. Several observations suggest weak agglomeration forces between the particles. A temperature reduction of 200 °C for sintering powder compacts was observed. KW - Laser KW - SiO2 KW - Nanopowder PY - 2013 DO - https://doi.org/10.4416/JCST2012-00033 SN - 2190-9385 N1 - Geburtsname von Wirth, Cynthia: Gomes, C. M. - Birth name of Wirth, Cynthia: Gomes, C. M. VL - 4 IS - 1 SP - 11 EP - 18 PB - Göller CY - Baden-Baden AN - OPUS4-31423 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Kanzler, Daniel A1 - Müller, Christina A1 - Pitkänen, J. T1 - Probability of defect detection of Posiva's electron beam weld N2 - The report 'Probability of Defect Detection of Posiva's electron beam weld' describes POD curves of four NDT methods radiographic testing, ultrasonic testing, eddy current testing and visual testing. POD-curves are based on the artificial defects in reference blocks. The results are devoted to the demonstration of suitability of the methods for EB weld testing. Report describes methodology and procedure applied by BAM. Report creates a link from the assessment of the reliability and inspection performance to the risk assessment process of the canister final disposal project. Report ensures the confirmation of the basic quality of the NDT methods and their capability to describe the quality of the EB-weld. The probability of detection curves are determined based on the MIL-1823 standard and it's reliability guidelines. The MIL-1823 standard was developed for the determination of integrity of gas turbine engines for the US military. In the POD-process there are determined as a key parameter for the defect detectability the a90/95 magnitudes, i.e. the size measure a of the defect, for which the lower 95 % confidence band crosses the 90 % POD level. By this way can be confirmed that defects with a size of a90/95 will be detected with 90 % probability. In case the experiment will be repeated 5 % might fall outside this confidence limit. KW - Probability of detection curves KW - POD-curves KW - NDT-methods KW - EB-welding KW - Ultrasonic inspection KW - Radiographic inspection KW - Eddy current inspection KW - Visual inspection PY - 2013 UR - http://www.posiva.fi/en/databank/working_reports/probability_of_defect_detection_of_posiva_s_electron_beam_weld.1874.xhtml?xm_col_report_year=2013&xm_col_language=3&xm_col_type=5&cd_order=col_report_number&cd_offset=0#.VJAIY3uj_mc UR - http://www.posiva.fi/files/3527/WR_2013-70.pdf SP - 1 EP - 86 AN - OPUS4-32512 LA - eng 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 DO - 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 - Ried, Peter A1 - Gaber, Martin A1 - Müller, Ralf A1 - Deubener, J. T1 - Hydrogen permeability of a barium-aluminoborosilicate glass - A methodical approach N2 - The H2 effusion from H2 saturated glass powders, H2 permeation through the wall of blown glass bulbs, and H2 permeation through the wall of glass capillaries were applied to evaluate the permeability of hydrogen gas in a barium-aluminoborosilicate (BABS) glass. To validate these methods, two commercial glasses (vitreous silica and borosilicate) were used as a reference. Permeation values obtained from the different experiments agreed within a factor of 3 or less. The H2 permeability of BABS glass at temperatures close to ambient was found to be at least 3 orders of magnitude below that of borosilicate and silica glasses. The powder method, which requires minimal sample preparation efforts, turned out to provide easy access to the measurement of H2 permeability of glasses down to P = 3.9 × 10- 21 mol s- 1 Pa- 1 m- 1. KW - Hydrogen gas KW - Permeability KW - Solubility KW - Diffusivity KW - Aluminoborosilicate glass PY - 2014 DO - https://doi.org/10.1016/j.jnoncrysol.2014.04.006 SN - 0022-3093 VL - 394-395 SP - 43 EP - 49 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-30720 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bertovic, Marija A1 - Calmon, P. A1 - Carter, L. A1 - Fischer, J. A1 - Forsyth, D. A1 - Holstein, R. A1 - McGrath, B. A1 - Müller, Christina A1 - Pavlovic, Mato A1 - Ronneteg, U. A1 - Rummel, W. A1 - Schubert, F. A1 - Selby, G. T1 - Summary of the "open space technology discussions" on reliability of NDE N2 - Since the beginnings of the European American Workshops (EAW) in 1997, the aim was to gather the experts in NDE reliability and discuss burning topics with the aim of identifying crucial problems and suggesting ways to move forward. This was usually achieved during the so-called break-out sessions, in which predetermined topics were discussed. During the 5th EAW, held in Berlin in 2013, this approach was replaced by an Open Space Technology (OST) approach. The benefit of this approach is seen in the freedom of topic choices, i. e., the topics are not predetermined but rather arise at that moment in that space and by the participants’ choice. The following topics arose: new reliability methods (Bayesian, MAPOD, …), structural health monitoring, definition of requirements of NDE by customer versus provider, what value of POD is good enough?, human factors, manual versus automated inspection, and basic concepts of reliability of NDE. The participants were encouraged to walk from one session to another and openly express their opinions. These were in the end summarized by a chosen group of moderators and presented in this paper. N2 - Seit den Anfängen der europäischen amerikanischen Workshops (EAW) im Jahr 1997 war es das Ziel, Experten auf dem Gebiet der ZfP-Zuverlässigkeit zusammenzuführen und aktuelle Themen zu diskutieren, um wichtige Probleme zu identifizieren und Wege für deren Lösung vorzuschlagen. Dies wurde in der Regel während der sogenannten „Break-out Sessions“ erreicht, in denen vorgegebene Themen diskutiert wurden. Während des 5. EAW, der in Berlin im Jahr 2013 stattfand, wurde dieser Ansatz durch einen Open Space Technology (OST) Ansatz ersetzt. Open Space ist eine Methode der Gruppenmoderation, die sehr gut geeignet ist, um neue Ideen zu entwickeln und selbstständiges Arbeiten zu fördern, d. h. die Themen werden nicht vorgegeben, sondern ergeben sich in diesem Moment in diesem Raum und durch die Wahl der Teilnehmer. Die folgenden Themen wurden herausgearbeitet: neue Zuverlässigkeitsmethoden (Bayes, MAPOD, ...…), Structural Health Monitoring, Definition von Anforderungen der Kunden gegenüber den ZfP-Anbietern, Welcher Wert der POD ist gut genug?, der Einfluss menschlicher Faktoren, manuelle gegenüber automatisierte Prüfung, sowie Grundkonzepte der ZfP-Zuverlässigkeit. Die Teilnehmer wurden aufgefordert, von einer Sitzung zur anderen zu wechseln und offen ihre Meinung zu äußern. Diese Meinungen wurden am Ende von einer ausgewählten Gruppe von Moderatoren zusammengefasst und werden in diesem Beitrag vorgestellt. KW - NDE reliability KW - POD KW - Bayesian approach KW - Structural health monitoring KW - Human factors KW - Open space technology PY - 2014 UR - http://www.hanser-elibrary.com/doi/pdf/10.3139/120.110604 DO - https://doi.org/10.3139/120.110604 SN - 0025-5300 VL - 56 IS - 7-8 SP - 602 EP - 606 PB - Hanser CY - München AN - OPUS4-31269 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Nörthemann, K. A1 - Moritz, W. A1 - Bienge, J.-E. A1 - Müller, J. A1 - Despinasse, Marie-Claire A1 - Raspe, Tina A1 - Krüger, Simone ED - Krüll, W. T1 - Forest fire detection using hydrogen sensors N2 - Forest fires start mostly in partial combustion. In this paper we present a hydrogen sensor to defect early stages of forest fires. First indoor experiments in a smoke density chamber with wood samples, proved that the sensor produce a strong signal change when the smouldering of wood starts, already before the CO concentration, measured in FTIR spectrometry, exceeds 10 ppm. In outdoor experiments we were able to detect forest fire in a distance of 110 m. T2 - AUBE '14 - 15th International conference on automatic fire detection CY - Duisburg, Germany DA - 14.10.2014 KW - Hydrogen sensor KW - Forest KW - Fire detection KW - Smoke gases KW - FTIR KW - Rauchkammer PY - 2014 SN - 978-3-940402-02-8 VL - 1 SP - 247 EP - 254 CY - Duisburg AN - OPUS4-31949 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pitkänen, J. A1 - Bertovic, Marija A1 - Brackrock, Daniel A1 - Brekow, Gerhard A1 - Ewert, Uwe A1 - Kanzler, Daniel A1 - Müller, Christina T1 - Reliable evaluation of acceptability of weld for final disposal based on the canister copper weld inspection using different NDT methods N2 - The inspection of the sealing weld is an important phase for the evaluation of the acceptability of final disposal canister, but the weld is only a part of the 3D shielding of copper shell. The main tasks for reliable NDT evaluation requires an extensive evaluation of the parameters – which contains typical inspection related items like repeatability, S/N ratio, POD, setting up the equipment for inspection, and all practices for inspections. The other parameters are material parameters, their variation must be taken into account in the evaluation of NDT reliability. Further parameters include human factors, i. e. human inspectors and their interaction with technical systems; their effects were studied on an example of the evaluation of eddy current data. Final parameters are related to evaluation of detected defects, which means sizing and base for acceptance and this can be done in different ways. Some examples are given and results are compared with different methods for instance between radiographic testing and ultrasonic testing by raw data analysis and PA-SAFT results. Also, preliminary curves for the evaluation of metallographic results of 55 defects will be shown by EB weld measurements. Some practical items concerning copper inspections will be also discussed related to acceptability. N2 - Die Prüfung der Verschlussschweißnaht ist eine wichtige Phase in der Akzeptanzbewertung der Endlagerungskanister, obwohl die Verschlussschweißnaht nur ein Teil der dreidimensionalen Bedeckung der Kupfereinhüllung ist. Die Hauptaufgabe für die sichere zerstörungsfreie Prüfung (ZfP) erfordert eine umfangreiche Bewertung der Prüfparameter, die die typischen Prüfeinzelheiten, wie z. B. Wiederholbarkeit, Signal-Rausch-Verhältnis, POD, Einstellung der Geräte und alle Prüfvorgehen enthalten. Weitere Parameter sind die Schwankungen von Materialeigenschaften, die berücksichtigt werden müssen. Andere Parameter sind menschliche Faktoren, wie z. B. die Prüfer, und deren Interaktion mit den technischen Systemen, beispielsweise bei der Bewertung der Wirbelstromdaten. Weitere Einflussgrößen auf die Prüfung entstehen bei der Bewertung gefundener Fehler, bei der Größenbestimmung von Fehlern und basierend auf der strukturellen Integrität bei der Akzeptanz von definierten Fehlergrößen/Fehlerarten an verschiedenen Positionen in der Schweißnaht. Der Artikel zeigt einige Beispiele und den Vergleich zwischen verschiedenen ZfP-Methoden, z. B. der radiographische Prüfung, der Ultraschallprüfung mit Bewertung von Rohdaten und der Ultraschallprüfung mit Bewertung mittels PA-SAFT. Auch die vorläufigen Kurven für die metallographische Bewertung von 55 Fehlern der Elektronenstrahlschweißung sind gezeigt. Darüber hinaus wird auch eine praktische Vorgehensweise bei der Definition der Akzeptanzkriterien für die Kupferschweißnahtsprüfung diskutiert. KW - NDT reliability KW - Radiography KW - Ultrasonic testing KW - Eddy current testing KW - Visual testing PY - 2014 UR - http://www.hanser-elibrary.com/doi/pdf/10.3139/120.110609 DO - https://doi.org/10.3139/120.110609 SN - 0025-5300 VL - 56 IS - 9 SP - 748 EP - 757 PB - Hanser CY - München AN - OPUS4-31524 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stephan, H. A1 - Walther, M. A1 - Fähnemann, S. A1 - Ceroni, P. A1 - Molloy, J.K. A1 - Bergamini, G. A1 - Heisig, F. A1 - Müller, C.E. A1 - Kraus, Werner A1 - Comba, P. T1 - Bispidines for dual imaging N2 - The efficient transformation of the hexadentate bispidinol 1 into carbamate derivatives yields functional bispidines enabling convenient functionalization for targeted imaging. The BODIPY-substituted bispidine 3 combines a coordination site for metal ions, such as radioactive 64CuII, with a fluorescent unit. Product 3 was thoroughly characterized by standard analytical methods, single crystal X-ray diffraction, radiolabeling, and photophysical analysis. The luminescence of ligand 3 was found to be strongly dependent on metal ion coordination: CuII quenches the BODIPY fluorescence, whereas NiII and ZnII ions do not affect it. It follows that, in imaging applications with the positron emitter 64CuII, residues of its origin from enriched 64Ni and the decay products 64NiII and 64ZnII, efficiently restore the fluorescence of the ligand. This allows for monitoring of the emitted radiation as well as the fluorescence signal. The stability of the 64CuII–3 complex is investigated by transmetalation experiments with ZnII and NiII, using fluorescence and radioactivity detection, and the results confirm the high stability of 64CuII–3. In addition, metal complexes of ligand 3 with the lanthanide ions TbIII, EuIII, and NdIII are shown to exhibit emission of the BODIPY ligand and the lanthanide ion, thus enabling dual emission detection. KW - Bispidines KW - Chelates KW - Imaging agents KW - Lanthanides KW - Radiolabeling KW - Nuclear medical application KW - Radioactive labelling KW - SPECT PY - 2014 DO - https://doi.org/10.1002/chem.201404086 SN - 0947-6539 SN - 1521-3765 VL - 20 IS - 51 SP - 17011 EP - 17018 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-32320 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mühler, T. A1 - Helsch, G. A1 - Heinrich, J.G. A1 - Yao, Dongxu A1 - Gräf, S. A1 - Müller, F.A. A1 - Günster, Jens T1 - Strategies for the selective volume sintering of ceramics N2 - The present study is dealing with the basic physics for a novel way to generate a free-formed ceramic body, not like common layer by layer, but directly by Selective Volume Sintering (SVS) in a compact block of ceramic powder. To penetrate with laser light into the volume of a ceramic powder compact it is necessary to investigate the light scattering properties of ceramic powders. Compared with polymers and metals, ceramic materials are unique as they offer a wide optical window of transparency. The optical window typically ranges from below 0.3 up to 5 µm wave length. In the present study thin layers of quartz glass (SiO2) particles have been prepared. As a function of layer thickness and the particle size, transmission and reflection spectra in a wave length range between 0.5 and 2.5 µm have been recorded. Depending on the respective particle size and by choosing a proper relation between particle size and wave length of the incident laser radiation, it is found that light can penetrate a powder compact up to a depth of a few millimeters. With an adjustment of the light absorption properties of the compact the initiation of sintering in the volume of the compact is possible. KW - Additive Manufacturing PY - 2014 DO - https://doi.org/10.1557/jmr.2014.174 SN - 0884-2914 VL - 29 IS - 17 SP - 2095 EP - 2099 PB - Materials Research Society CY - Warrendale, Pa. AN - OPUS4-32544 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -