TY - CONF A1 - Ehrig, Karsten A1 - Goebbels, Jürgen A1 - Meinel, Dietmar A1 - Paetsch, O. A1 - Prohaska, S. A1 - Zobel, Valentin T1 - Comparison of crack detection methods for analyzing damage processes in concrete with computed tomography T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography (Proceedings) N2 - Analyzing damages at concrete structures due to physical, chemical, and mechanical exposures need the application of innovative non-destructive testing methods that are able to trace spatial changes of microstructures. Here, the utility of three different crack detection methods for the analysis of computed tomograms of various cementitious building materials is evaluated. Due to the lack of reference samples and standardized image quality evaluation procedures, the results are compared with manually segmented reference data sets. A specific question is how automatic crack detection can be used for the quantitative characterization of damage processes, such as crack length and volume. The crack detection methods have been integrated into a scientific visualization system that allows displaying the tomography images as well as presenting the results. T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Crack detection KW - Computed tomography KW - Data visualization PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243569 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Poster 2) SP - 1 EP - 8 PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24356 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kupsch, Andreas A1 - Hentschel, Manfred P. A1 - Lange, Axel A1 - Grothausmann, R. A1 - Manke, I. T1 - Application of the DIRECTT algorithm to sub-nanometer electron tomography T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography (Proceedings) N2 - Tomography data obtained from transmission electron microscopes are especially attractive due to their unrivaled spatial resolution in the nanometer range or even less, but they require enormous efforts in sample preparation and suffer from a diverse accumulation of experimental restrictions, which unavoidably result in fundamental reconstruction artifacts. These restrictions refer to: partial opacity, a limited view (limited angle or missing wedge), very few angles (with respect to the detector size), limited to a region of interest (ROI; due to the sample size), variable angular increments as well as sample degradation due the interactions with the electron beam. An advanced version of the DIRECTT (Direct Iterative Reconstruction of Computed Tomography Trajectories) algorithm proves to cope with most of these severe deviations from ideal CT measuring conditions. However, careful data preprocessing is required in order to exploit the capabilities of the algorithm. Nanometer sized Ruthenium catalyst particles for fuel cell applications are 3D imaged at a few Ångström resolution in order to estimate their partial free surface on carbon black supports, which rule the efficiency of the catalytic activity. Comparisons of DIRECTT reconstructions to the conventional filtered back projection, prove the significant improvements. T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Electron tomography KW - Computed tomography KW - Reconstruction algorithms PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243577 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Tu.3.3) SP - 1 EP - 6 PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Osterloh, Kurt A1 - Fratzscher, Daniel A1 - Jechow, Mirko A1 - Bücherl, T. A1 - Schillinger, B. A1 - Hasenstab, A. A1 - Zscherpel, Uwe A1 - Ewert, Uwe T1 - Limited view tomography of wood with fast and thermal neutrons T2 - DGZfP-Berichtsband N2 - Neutrons are absorbed particularly by hydrogen containing materials so they can be used as a tool for visualising heterogeneous density distributions of organic materials. Penetration limits are set by the layer thicknesses and the neutron energies applied. In case of specimens with a flat shape the situation may be encountered that the object only could be penetrated in selected directions. In addition, the overall size may exceed the beam diameter and thus the viewing window if a certain region of interest should be studied by tomography without destroying the integrity of the specimen. This study shows the capabilities and limits of thermal and fast neutrons to investigate flat wooden specimens such as boards and girders by neutron tomography under such circumstances. Taking projections was impaired either by the limits of penetrability or by the total size of the object. As a consequence, projections were included for reconstruction only from a limited angular range of 90°. It could be shown that an approach based on the slice theorem was capable to visualise structural features along the beam directions while simply omitting the perpendicular ones without causing additional artefacts. Small samples with a thickness of up to 2 cm but several times broader could be studied with the ANTARES facility of the FRM II neutron source in Garching providing thermal neutrons while larger objects required a beam of higher energy as available in the NECTAR facility of the same institution. The fast (fission) neutrons (1.5 – 2 MeV) of this site allowed investigating an area of interest inside a girder with a cross section of 23.5 x 49 cm². Internal features such as inclusions could be detected as well as a heterogeneous density distribution in glue layers. T2 - International symposium on digital industrial radiology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Computed tomography KW - Slice theoreme KW - Limited angle tomography PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-250663 SN - 978-3-940283-34-4 VL - 128 SP - 1 EP - 5 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-25066 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 - Müller, Bernd R. T1 - Correction of diffuse X-ray detector based background T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography (Proceedings) N2 - A novel approach to strongly suppress artifacts in radiography and computed tomography caused by the effect of diffuse background Signals (“backlight”) of 2D X-ray detectors is suggested. Depending on the detector geometry the mechanism may be different, either based on the optical scattering of the fluorescent screen materials into optical detection devices or Compton or X-ray fluorescence scattering by the detector components. Consequently, these erroneous intensity portions result in locally different violations of Lambert Beer’s law in single projections (radiographs). When used as input data for computed tomography these violations are directly observed via modulation of the projected mass as a function of the rotation Phase and the sample’s aspect ratio (dynamics). The magnitude of the diffuse Background signal depends on the detector area covered by the projected sample. They are more pronounced the smaller the shaded area and the stronger the total attenuation. Moreover, the local intensity mismatch depends on the attenuation of the sample. We present very basic reference data measured with multiple metal foils at a synchrotron radiation source. Beam hardening artifacts can be excluded due to the monochromatic radiation. The proposed correction procedure assumes a constant (non-local) scattering mechanism. T2 - DIR 2011 - International symposium on digital industrial raidology and computed tomography CY - Berlin, Germany DA - 20.06.2011 KW - Backlight KW - X-ray detector KW - Fluorescence screen KW - Synchrotron radiography KW - Computed tomography PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-243589 SN - 978-3-940283-34-4 IS - DGZfP-BB 128 (Poster 24) SP - 1 EP - 7 PB - Deutsche Gesellscahft für Zerstörungsfreie Prüfung e.V. (DGZfP) AN - OPUS4-24358 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Laquai, René A1 - Schaupp, Thomas A1 - Griesche, Axel A1 - Müller, Bernd R. A1 - Kupsch, Andreas A1 - Hannemann, Andreas A1 - Kannengießer, Thomas A1 - Bruno, Giovanni T1 - Quantitative analysis of hydrogen-assisted microcracking in duplex stainless steel through X-ray refraction 3D imaging JF - Advanced engineering materials N2 - While the problem of the identification of mechanisms of hydrogen assisted damage has and is being thoroughly studied, the quantitative analysis of such damage still lacks suitable tools. In fact, while, for instance, electron microscopy yields excellent characterization, the quantitative analysis of damage requires at the same time large field-of-views and high spatial resolution. Synchrotron X-ray refraction techniques do possess both features. In this work, we show how synchrotron X-ray refraction computed tomography (SXRCT) can quantify damage induced by hydrogen embrittlement in a lean duplex steel, yielding results that overperform even those achievable by synchrotron X-ray absorption computed tomography. As already reported in literature, but this time using a non-destructive technique, we show that the hydrogen charge does not penetrate to the center of tensile specimens. By the comparison between virgin and hydrogen-charged specimens, we deduce that cracks in the specimen bulk are due to the rolling process rather than hydrogen-assisted. We show that (micro)cracks propagate from the surface of tensile specimens to the interior with increasing applied strain, and we deduce that a significant crack propagation can only be observed short before rupture. KW - 2101 duplex stainless steel KW - Hydrogen embrittlement KW - Synchrotron radiation KW - X-ray refraction KW - Computed tomography KW - Microcracking PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-542811 DO - https://doi.org/10.1002/adem.202101287 SN - 1438-1656 SP - 1 EP - 10 PB - Wiley-VCH CY - Weinheim AN - OPUS4-54281 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Fritsch, Tobias A1 - Farahbod-Sternahl, L. A1 - Serrano Munoz, Itziar A1 - Léonard, F. A1 - Haberland, C. A1 - Bruno, Giovanni T1 - 3D Computed Tomography Quantifies the Dependence of Bulk Porosity, Surface Roughness, and Re-Entrant Features on Build Angle in Additively Manufactured IN625 Lattice Struts JF - Advanced Engineering Materials N2 - Layer-by-layer additive manufacturing (AM) by means of laser-powder bed Fusion (L-PBF) offers many prospects regarding the design of lattice structures used, for example, in gas turbines. However, defects such as bulk porosity, Surface roughness, and re-entrant features are exacerbated in nonvertical structures, such as tilted struts. The characterization and quantification of these kinds of defects are essential for the correct estimation of fracture and fatigue properties. Herein, cylindrical struts fabricated by L-PBF are investigated by means of X-ray computed tomography (XCT), with the aim of casting light on the dependence of the three kinds of defects (bulk porosity, surface roughness, and re-entrant features) on the build angle. Innovative analysis methods are proposed to correlate shape and position of pores, to determine the angular-resolved Surface roughness, and to quantify the amount of re-entrant surface features, q. A meshing of the XCT surface enables the correlation of q with the classical Surface roughness Pa. This analysis leads to the conclusion that there is a linear correlation between q and Pa. However, it is conjectured that there must be a threshold of surface roughness, below which no re-entrant features can be build. KW - Additive manufacturing KW - Laser powder bed fusion KW - Computed tomography KW - Surface roughness analysis KW - Re-entrant surface feature PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-534728 DO - https://doi.org/10.1002/adem.202100689 IS - 2100689 SP - 1 EP - 8 PB - Wiley-VCH Verlag AN - OPUS4-53472 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Magkos, Sotirios A1 - Kupsch, Andreas A1 - Bruno, Giovanni T1 - Suppression of Cone-Beam Artefacts with Direct Iterative Reconstruction Computed Tomography Trajectories (DIRECTT) JF - Journal of Imaging N2 - The reconstruction of cone-beam computed tomography data using filtered back-projection algorithms unavoidably results in severe artefacts. We describe how the Direct Iterative Reconstruction of Computed Tomography Trajectories (DIRECTT) algorithm can be combined with a model of the artefacts for the reconstruction of such data. The implementation of DIRECTT results in reconstructed volumes of superior quality compared to the conventional algorithms. KW - DIRECTT KW - Iterative method KW - Signal processing KW - X-ray imaging KW - Computed tomography PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531085 DO - https://doi.org/10.3390/jimaging7080147 SN - 2313-433X) VL - 7 IS - 8 SP - 147 - 1 EP - 147 -9 PB - MDPI CY - Basel, Switzerland AN - OPUS4-53108 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Khrapov, D. A1 - Kozadayeva, M. A1 - Manabaev, K. A1 - Panin, A. A1 - Sjöström, W. A1 - Koptyug, A. A1 - Mishurova, Tatiana A1 - Evsevleev, Sergei A1 - Meinel, Dietmar A1 - Bruno, Giovanni A1 - Cheneler, D. A1 - Surmenev, R. A1 - Surmeneva, M. T1 - Different approaches for manufacturing Ti-6Al-4V alloy with triply periodic minimal surface sheet-based structures by electron beam melting JF - Materials N2 - Targeting biomedical applications, Triply Periodic Minimal Surface (TPMS) gyroid sheet-based structures were successfully manufactured for the first time by Electron Beam Melting in two different production Themes, i.e., inputting a zero (Wafer Theme) and a 200 µm (Melt Theme) wall thickness. Initial assumption was that in both cases, EBM manufacturing should yield the structures with similar mechanical properties as in a Wafer-mode, as wall thickness is determined by the minimal beam spot size of ca 200 µm. Their surface morphology, geometry, and mechanical properties were investigated by means of electron microscopy (SEM), X-ray Computed Tomography (XCT), and uniaxial tests (both compression and tension). Application of different manufacturing Themes resulted in specimens with different wall thicknesses while quasi-elastic gradients for different Themes was found to be of 1.5 GPa, similar to the elastic modulus of human cortical bone tissue. The specific energy absorption at 50% strain was also similar for the two types of structures. Finite element simulations were also conducted to qualitatively analyze the deformation process and the stress distribution under mechanical load. Simulations demonstrated that in the elastic regime wall, regions oriented parallel to the load are primarily affected by deformation. We could conclude that gyroids manufactured in Wafer and Melt Themes are equally effective in mimicking mechanical properties of the bones. KW - Electron beam melting KW - Scaffold KW - Lightweight structures KW - Computed tomography PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-531595 DO - https://doi.org/10.3390/ma14174912 SN - 1996-1944 VL - 14 IS - 17 SP - 1 EP - 21 PB - MDPI CY - Basel AN - OPUS4-53159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markötter, Henning A1 - Sintschuk, Michael A1 - Britzke, Ralf A1 - Dayani, Shahabeddin A1 - Bruno, Giovanni T1 - Upgraded imaging capabilities at the BAMline (BESSY II) JF - Journal of Synchrotron Radiation N2 - The BAMline at the BESSY II synchrotron X-ray source has enabled research for more than 20 years in widely spread research fields such as materials science, biology, cultural heritage and medicine. As a nondestructive characterization method, synchrotron X-ray imaging, especially tomography, plays a particularly important role in structural characterization. A recent upgrade of key equipment of the BAMline widens its imaging capabilities: shorter scan acquisition times are now possible, in situ and operando studies can now be routinely performed, and different energy spectra can easily be set up. In fact, the upgraded double-multilayer monochromator brings full flexibility by yielding different energy spectra to optimize flux and energy resolution as desired. The upgraded detector (based on an sCMOS camera) also allows exploiting the higher flux with reduced readout times. Furthermore, an installed slip ring allows the sample stage to continuously rotate. The latter feature enables tomographic observation of processes occurring in the time scale of a few seconds. KW - Synchrotron radiation KW - Computed tomography KW - Double-multilayer monochromators KW - Pink beams KW - X-ray optics PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-556907 DO - https://doi.org/10.1107/S1600577522007342 SN - 1600-5775 VL - 29 IS - Pt 5 SP - 1292 EP - 1298 PB - International Union of Crystallography CY - Chester AN - OPUS4-55690 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Färber, C. A1 - Titschack, J. A1 - Schönberg, Chr. H. L. A1 - Ehrig, Karsten A1 - Boos, K. A1 - Illerhaus, Bernhard A1 - Asgaard, U. A1 - Bromley, R. G. A1 - Freiwald, A. A1 - Wisshak, M. ED - Bahn, M. ED - Fennel, K. ED - Kesselmeier, J. ED - Naqvi, S. W. A. T1 - Long-term macrobioerosion in the Mediterranean Sea assessed by micro-computed tomography JF - Biogeosciences Journal of European Geosciences Union N2 - Biological erosion is a key process for the recycling of carbonate and the formation of calcareous sediments in the oceans. Experimental studies showed that bioerosion is subject to distinct temporal variability, but previous long-term studies were restricted to tropical waters. Here, we present results from a 14-year bioerosion experiment that was carried out along the rocky limestone coast of the island of Rhodes, Greece, in the Eastern Mediterranean Sea, in order to monitor the pace at which bioerosion affects carbonate substrate and the sequence of colonisation by bioeroding organisms. Internal macrobioerosion was visualised and quantified by micro-computed tomography and computer-algorithm-based segmentation procedures. Analysis of internal macrobioerosion traces revealed a dominance of bioeroding sponges producing eight types of characteristic Entobia cavity networks, which were matched to five different clionaid sponges by spicule identification in extracted tissue. The morphology of the entobians strongly varied depending on the species of the producing sponge, its ontogenetic stage, available space, and competition by other bioeroders. An early community developed during the first 5 years of exposure with initially very low macrobioerosion rates and was followed by an intermediate stage when sponges formed large and more diverse entobians and bioerosion rates in-creased. After 14 years, 30 % of the block volumes were occupied by boring sponges, yielding maximum bioerosion rates of 900 g m. KW - Bioerosion KW - Computed tomography KW - Carbonate substrate PY - 2016 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-372709 UR - http://www.biogeosciences.net/13/3461/2016/bg-13-3461-2016.pdf DO - https://doi.org/10.5194/bg-13-3461-2016 VL - 13 IS - 11 SP - 3461 EP - 3474 PB - Copernicus Publications CY - Göttingen AN - OPUS4-37270 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -