TY - CONF A1 - Beck, Matthias A1 - Goebbels, Jürgen A1 - Meinel, Dietmar A1 - Burkert, Andreas ED - M.G. Alexander, ED - H.-D. Beushausen, ED - F. Dehn, ED - P. Moyo, T1 - DFG Research Group 537: Modelling reinforcement corrosion - Observation and monitoring of self-corrosion processes in chloride contaminated mortar by X-ray tomography T2 - 2nd International Conference on Concrete Repair, Rehabilitation and Retrofitting CY - Cape Town, South Africa DA - 2008-11-24 KW - Self-corrosion KW - X-ray tomography KW - Reinforcement KW - Concrete parameters KW - Metallographic section KW - Steel surface PY - 2009 SN - 978-0-415-46850-3 SP - 187 EP - 188 PB - CRC Press CY - Boca Raton AN - OPUS4-18438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Goebbels, Jürgen T1 - Scalability of CT - measurements T2 - Symposium on Computed Tomography applied to Dimensional Control, BAM CY - Berlin, Germany DA - 2009-10-06 PY - 2009 AN - OPUS4-19761 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Staude, Andreas A1 - Ehrig, Karsten A1 - Goebbels, Jürgen A1 - Bartscher, M. A1 - Hilpert, U. A1 - Koch, M. T1 - Methode und Prüfkörper zum Nachweis von Gussdefekten in Aluminiumbauteilen mit Computertomographie T2 - DGZfP-Jahrestagung 2009 CY - Münster, Deutschland DA - 2009-05-18 PY - 2009 SN - 978-3-940283-16-0 IS - DGZfP-BB 115 (Mi.4.B.2) SP - 1 EP - 8 AN - OPUS4-20728 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hoferer, J. A1 - Hoffmann, L.M. A1 - Goebbels, Jürgen A1 - Last, G. A1 - Weil, W. A1 - Kasper, G. T1 - Reconstruction algorithms for the internal packing density distribution of fibrous filter media based on tomographic data N2 - Algorithms were developed to approximate the 3-dimensional internal packing density distributions of fibrous filter media at different levels of detail and complexity. Each algorithm uses certain input information derived from X-ray tomographic data of filter samples. Algorithm 1 creates a binary media structure consisting of the true (i.e. tomographically determined) void distribution plus regions of uniform packing density. The average packing density of the media is maintained constant. Algorithm 2 creates a model fibrous structure of straight fibres of equal diameter and random length positioned randomly in space, while maintaining the true (i.e. tomographically determined) fibre orientation distribution. The number and length of the fibres on average adds up to the packing density of the filter. The model fibrous structure is recreated by a stationary Poisson process of convex bodies. Algorithm 3 distributes pores of random size and location within a homogeneous matrix, such that the average packing density again coincides with the true (i.e. tomographically determined) packing density. This algorithm is also based on a stationary Poisson process of convex bodies. The capability of each algorithm to recreate the essential structural features of the media was tested against 'reality' by computing the respective overall pressure drop of the filter as well as the velocity distribution in the filter interior, and comparing with the results obtained for the 'true' packing density distribution of a sample measured by tomography. Compared to the assumption of a completely homogenous filter (which gives roughly 2 times the actual Δp), all algorithms are closer to reality. The binary algorithm deviates in Δp by a factor of 1.8; algorithm 3 comes within a factor of 1.6 of the true Δp. The best approximation is by algorithm 2 which narrows the difference in Δp to a factor of 1.4. KW - X-ray tomography KW - Fibrous filter KW - Packing density PY - 2009 SN - 1479-0602 VL - 9 IS - 2 SP - 147 EP - 154 PB - Filtration Solutions CY - Newbold, Coleorton, Coalville AN - OPUS4-22880 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jungnikl, K. A1 - Goebbels, Jürgen A1 - Burgert, I. A1 - Fratzl, P. T1 - The role of material properties for the mechanical adaptation at branch junctions N2 - Branch junctions are mechanically particularly interesting areas of trees, because they have to withstand a combination of static and dynamic loads, from the stem as well as from the branch. In the present work, the local adaptation of material properties at branch junctions was assessed by mapping microfibril angle and tissue density. Images of the density distribution were obtained by computer tomography (CT). Wide angle X-ray scattering (WAXS) was used to determine the microfibril angle distribution with high-resolution around the junctions. The stem tissue around the junctions showed increased density and microfibril angle, which points towards an optimisation for fracture toughness. The tissue at the branch bases showed low density combined with high MFA, which provides deformability and flexibility and might act as protection of the stem against load transmission from the branch. KW - Branch junction KW - Computer tomography (CT) KW - Microfibril angle (MFA) KW - Notch stresses KW - Wide angle X-ray scattering (WAXS) PY - 2009 U6 - https://doi.org/10.1007/s00468-008-0305-9 SN - 0931-1890 VL - 23 IS - 3 SP - 605 EP - 610 PB - Springer CY - Berlin ; Heidelberg AN - OPUS4-22887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stiller, M. A1 - Rack, A. A1 - Zabler, S. A1 - Goebbels, Jürgen A1 - Dalügge, O. A1 - Jonscher, S. A1 - Knabe, C. T1 - Quantification of bone tissue regeneration employing Beta-tricalcium phosphate by three-dimensional non-invasive synchrotron micro-tomography - A comparative examination with histomorphometry KW - Sinus floor augmentation KW - Histomorphometry KW - Synchrotron micro-tomography KW - Multi-dimensional microscopy KW - Histovolumetry PY - 2009 U6 - https://doi.org/10.1016/j.bone.2008.10.049 SN - 8756-3282 VL - 44 IS - 4 SP - 619 EP - 628 PB - Elsevier CY - New York, NY, USA AN - OPUS4-22888 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Beck, Matthias A1 - Goebbels, Jürgen A1 - Isecke, Bernd A1 - Burkert, Andreas A1 - Mietz, Jürgen T1 - Investigations of corrosion on small cathodes in reinforced concrete - observations and suggestions N2 - Corrosion of steel reinforcement in concrete exposed to chloride containing environments is a serious problem in civil engineering practice. The standards and guidelines contain only minimum requirements regarding concrete quality and concrete cover. In very critical cases, for example the ingress of chlorides, the application of different coatings is currently the only possibility to protect the reinforced concrete structures. In this case the modelling of reinforcement corrosion would be more practical. One sub-project of a DFG-research project (FOR 537) is currently performed at the Federal Institute for Materials Research and Testing (BAM). Aim of the sub-project is the description of corrosion propagation and the characterization of the corrosion on specimens with small cathodes by electrochemical parameters. The electrochemical parameters are determined by suitable electrochemical measurements, considering concrete parameters as well as different environmental conditions. T2 - EUROCORR 2009 CY - Nice, France DA - 2009-09-06 KW - Self-corrosion KW - Steel reinforcement KW - Concrete parameters KW - X-ray tomography PY - 2009 IS - Paper 7976 SP - 1 EP - 13 AN - OPUS4-20063 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -