TY - RPRT A1 - Kalbe, Ute A1 - Witt, K. J. A1 - Simon, Franz-Georg A1 - Prohaska, S. A1 - Slowik, V. T1 - Bedingungen suffosiver Erosionsphänomene in Böden N2 - Für eine detaillierte Analyse der Gefüge- und Porenstruktur weitgestufter Erdstoffe ist es notwendig, diese dreidimensional (3D) zu visualisieren und ihre Kenngrößen zu ermitteln. Dazu wurde an der BAM eine Präparationsmethode entwickelt, die es ermöglicht die Porenstruktur von Probenkörpern aus suffosiven Erdstoffen und definierten Korngrößenverteilungen über CT-Aufnahmen abzubilden. Über eine eigens dafür, in Zusammenarbeit mit dem Zuse-Institut Berlin (ZIB), entwickelte Bildanalysemethode wurden die Strukturdaten visualisiert. Aus dem Bilddatensatz konnte bereits in der Rückwärtsrechnung eine Kornverteilungslinie zur Validierung generiert und mit experimentell ermittelten Sieblinien verglichen werden. Des Weiteren wurden in Säulenexperimenten Kornumlagerungsprozesse unter der Verwendung von CT-Aufnahmen beobachtet. Als eine weitere Möglichkeit zur Beschreibung von Gefüge- und Porenstrukturen wurden Kugelpackungen modelliert und deren Strukturdaten ermittelt. Mit einem an der HTWK entwickelten stochastisch-heuristischen Algorithmus lassen sich wirklichkeitsnahe 3D-Gefügemodelle aus kugelförmigen Feststoffpartikeln generieren. Die Kornverteilung ist dabei wählbar. Für die erstellten Gefügemodelle kann der vollständige Porengraph einschließlich der Porengrößen und Engstellen ermittelt und ausgelesen werden. Ein an der BAM entwickelter und durch die BUW erweiterter Säulenversuch unter Verwendung systematisch veränderter Korngemische von natürlichen Gesteinskörnungen und Glaskugeln ergab weitere Aufschlüsse über die strukturbildenden Fraktionen des Korngerüstes. Die Perkolationstheorie ist eine moderne wahrscheinlichkeitstheoretische Methode, um Fluss- und Transportvorgänge innerhalb poröser Medien zu simulieren. Über Porennetzwerkmodelle werden die komplexen Fließwege in der Porenstruktur vereinfacht abgebildet. An der BUW wurde ein 3D-Bond-Perkolationsmodell auf einem simplen kubischen Gitter realisiert, in dem die Gitterknoten die Poren und die Gitterstäbe die Porenengstellen repräsentieren. Lokale und globale Strukturveränderungen infolge Partikeltransports werden über die Analyse von Porenräumen beschrieben. Mit diesem Perkolationsmodell können Aussagen zur lokalen und globalen Strukturveränderung durch Partikeltransport in definierten Bodenvolumen abgeleitet werden. Die hergeleiteten Zusammenhänge zu den suffosiven Materialtransportbedingungen mit der Perkolationstheorie sind für homogene, isotrope und selbstähnliche Erdstoffgefüge gültig. KW - Wasserbau KW - Bodenmechanik PY - 2012 VL - SI 1382/1-2 SP - 1 EP - 24 AN - OPUS4-52427 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Prohaska, T. A1 - Irrgeher, J. A1 - Benefield, J. A1 - Böhlke, J. K. A1 - Chesson, L. A. A1 - Coplen, T. B. A1 - Ding, T. A1 - Dunn, P. J. H. A1 - Gröning, M. A1 - Holden, N. E. A1 - Meijer, H. A. J. A1 - Moossen, H. A1 - Possolo, A. A1 - Takahashi, Y. A1 - Vogl, Jochen A1 - Walczyk, T. A1 - Wang, J. A1 - Wieser, M. E. A1 - Yoneda, S. A1 - Zhu, X.-K. A1 - Meija, J. T1 - Standard atomic weights of the elements 2021 (IUPAC Technical Report) N2 - Following the reviews of atomic-weight determinations and other cognate data in 2015, 2017, 2019 and 2021, the IUPAC (International Union of Pure and Applied Chemistry) Commission on Isotopic Abundances and Atomic Weights (CIAAW) reports changes of standard atomic weights. The symbol Ar(E) was selected for standard atomic weight of an element to distinguish it from the atomic weight of an element E in a specific substance P, designated Ar(E, P). The CIAAW has changed the values of the standard atomic weights of five elements based on recent determinations of terrestrial isotopic abundances: Ar (argon): from 39.948 ± 0.001 to [39.792, 39.963] Hf (hafnium): from 178.49 ± 0.02 to 178.486 ± 0.006 Ir (iridium): from 192.217 ± 0.003 to 192.217 ± 0.002 Pb (lead): from 207.2 ± 0.1 to [206.14, 207.94] Yb (ytterbium): from 173.054 ± 0.005 to 173.045 ± 0.010 The standard atomic weight of argon and lead have changed to an interval to reflect that the natural variation in isotopic composition exceeds the measurement uncertainty of Ar(Ar) and Ar(Pb) in a specific substance. The standard atomic weights and/or the uncertainties of fourteen elements have been changed based on the Atomic Mass Evaluations 2016 and 2020 accomplished under the auspices of the International Union of Pure and Applied Physics (IUPAP). Ar of Ho, Tb, Tm and Y were changed in 2017 and again updated in 2021: Al (aluminium), 2017: from 26.981 5385 ± 0.000 0007 to 26.981 5384 ± 0.000 0003 Au (gold), 2017: from 196.966 569 ± 0.000 005 to 196.966 570 ± 0.000 004 Co (cobalt), 2017: from 58.933 194 ± 0.000 004 to 58.933 194 ± 0.000 003 F (fluorine), 2021: from 18.998 403 163 ± 0.000 000 006 to 18.998 403 162 ± 0.000 000 005 (Ho (holmium), 2017: from 164.930 33 ± 0.000 02 to 164.930 328 ± 0.000 007) Ho (holmium), 2021: from 164.930 328 ± 0.000 007 to 164.930 329 ± 0.000 005 Mn (manganese), 2017: from 54.938 044 ± 0.000 003 to 54.938 043 ± 0.000 002 Nb (niobium), 2017: from 92.906 37 ± 0.000 02 to 92.906 37 ± 0.000 01 Pa (protactinium), 2017: from 231.035 88 ± 0.000 02 to 231.035 88 ± 0.000 01 Pr (praseodymium), 2017: from 140.907 66 ± 0.000 02 to 140.907 66 ± 0.000 01 Rh (rhodium), 2017: from 102.905 50 ± 0.000 02 to 102.905 49 ± 0.000 02 Sc (scandium), 2021: from 44.955 908 ± 0.000 005 to 44.955 907 ± 0.000 004 (Tb (terbium), 2017: from 158.925 35 ± 0.000 02 to 158.925 354 ± 0.000 008) Tb (terbium), 2021: from 158.925 354 ± 0.000 008 to 158.925 354 ± 0.000 007 (Tm (thulium), 2017: from 168.934 22 ± 0.000 02 to 168.934 218 ± 0.000 006) Tm (thulium), 2021: from 168.934 218 ± 0.000 006 to 168.934 219 ± 0.000 005 (Y (yttrium), 2017: from 88.905 84 ± 0.000 02 to 88.905 84 ± 0.000 01) Y (yttrium), 2021: from 88.905 84 ± 0.000 01 to 88.905 838 ± 0.000 002 KW - Argon KW - Ciaaw.org KW - Hafnium KW - Iridium KW - Lead KW - LSVEC KW - Ytterbium PY - 2022 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-548443 DO - https://doi.org/10.1515/pac-2019-0603 SN - 0033-4545 VL - 94 IS - 5 SP - 573 EP - 600 PB - De Gruyter Verlag CY - Berlin AN - OPUS4-54844 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kazlagić, Anera A1 - Rosner, M. A1 - Cipriani, A. A1 - Frick, D. A. A1 - Glodny, J. A1 - Hoffmann, E. J. A1 - Hora, J. M. A1 - Irrgeher, J. A1 - Lugli, F. A1 - Magna, T. A1 - Meisel, T. C. A1 - Meixner, A. A1 - Possolo, A. A1 - Pramann, A. A1 - Pribil, M. J. A1 - Prohaska, T. A1 - Retzmann, A. A1 - Rienitz, O. A1 - Rutherford, D. A1 - Paula-Santos, G. M. A1 - Tatzel, M. A1 - Widhalm, S. A1 - Willbold, M. A1 - Zuliani, T. A1 - Vogl, Jochen T1 - Data of the characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study N2 - This dataset represents the electronic supplementary material (ESM) of the publication entitled "Characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study", which is published in Geostandards and Geoanalytical Research under the DOI: 10.1111/GGR.12517. It consists of four files. 'ESM_Data.xlsx' contains all reported data of the participants, a description of the applied analytical procedures, basic calculations, the consensus values, and part of the uncertainty assessment. 'ESM_Figure-S1' displays a schematic on how measurements, sequences and replicates are treated for the uncertainty calculation carried out by PTB. 'ESM_Technical-protocol.pdf' is the technical protocol of the interlaboratory comparison, which has been provided to all participants together with the samples and which contains bedside others the definition of the measurand and guidelines for data assessment and calculations. 'ESM_Reporting-template.xlsx' is the Excel template which has been submitted to all participants for reporting their results within the interlaboratory comparison. Excel files with names of the the structure 'GeoReM_Material_Sr8786_Date.xlsx' represent the Rcon(87Sr/86Sr) data for a specific reference material downloaded from GeoReM at the specified date, e.g. 'GeoReM_IAPSO_Sr8786_20221115.xlsx' contains all Rcon(87Sr/86Sr) data for the IAPSO seawater standard listed in GeoReM until 15 November 2022. KW - Reference data KW - Strontium isotope ratio KW - Interlaboratory comparison KW - Reference material KW - Cement KW - Geological material KW - Value assignment KW - Measurement uncertainty KW - Conventional method PY - 2023 UR - https://doi.org/10.5281/zenodo.7804445 DO - https://doi.org/10.5281/zenodo.7804444 PB - Zenodo CY - Geneva AN - OPUS4-57809 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kazlagić, Anera A1 - Rosner, M. A1 - Cipriani, A. A1 - Frick, D. A. A1 - Glodny, J. A1 - Hoffmann, E. J. A1 - Hora, J. M. A1 - Irrgeher, J. A1 - Lugli, F. A1 - Magna, T. A1 - Meisel, T. C. A1 - Meixner, A. A1 - Possolo, A. A1 - Pramann, A. A1 - Pribil, M. J. A1 - Prohaska, T. A1 - Retzmann, Anika A1 - Rienitz, O. A1 - Rutherford, D. A1 - Paula-Santos, G. M. A1 - Tatzel, M. A1 - Widhalm, S. A1 - Willbold, M. A1 - Zuliani, T. A1 - Vogl, Jochen T1 - Characterisation of conventional 87Sr/86Sr isotope ratios in cement, limestone and slate reference materials based on an interlaboratory comparison study N2 - An interlaboratory comparison (ILC)was organised to characterise 87Sr/86Sr isotope ratios in geological and industrial reference materials by applying the so-called conventional method for determining 87Sr/86Sr isotope ratios. Four cements (VDZ 100a,VDZ 200a, VDZ 300a, IAG OPC-1), one limestone (IAG CGL ML-3) and one slate (IAG OU-6) reference materials were selected, covering a wide range of naturally occurring Sr isotopic signatures. Thirteen laboratories received aliquots of these six reference materials together with a detailed technical protocol. The consensus values for the six reference materials and their associated measurement uncertainties were obtained by applying a Gaussian, linear mixed effects model fitted to all the measurement results. By combining the consensus values and their uncertainties with an uncertainty contribution for potential heterogeneity, reference values ranging from 0.708134 mol mol-1 to 0.729778 mol mol-1 were obtained with relative expanded uncertainties of ≤ 0.007 %. This study represents an ILC on conventional 87Sr/86Sr isotope ratios, within which metrological principles were considered and the compatibility of measurement results obtained by MC-ICP-MS and by MC-TIMS is demonstrated. The materials characterised in this study can be used as reference materials for validation and quality control purposes and to estimate measurement uncertainties in conventional 87Sr/86Sr isotope ratio measurement. KW - Sr isotope analysis KW - Isotope ratios KW - Cement KW - Geological material KW - MC-TIMS KW - MC-ICP-MS KW - Interlaboratory comparison KW - Measurement uncertainty KW - Cconventional method PY - 2023 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-579836 DO - https://doi.org/10.1111/ggr.12517 SN - 1639-4488 VL - 47 IS - 4 SP - 821 EP - 840 PB - Wiley online library AN - OPUS4-57983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Rottmann, L. A1 - Jakubowski, Norbert A1 - Konegger-Kappel, S. A1 - Hanousek, O. A1 - Prohaska, T. ED - Prohaska, T. ED - Irrgeher, J. ED - Zitek, A. ED - Jakubowski, Norbert T1 - Technical background N2 - The major components of sector field instruments can be listed as follows and will be described in more detail in the following chapter. (Specific details for the different types of instruments will be given in the corresponding instrumental sections in Chapters 11-17.) The general principle of all mass spectrometers follows ionisation after sample introduction, Separation of the ions according to their mlz ratio and final detection at the detection unit. The transport and Separation of ions follow the principles of ion optics. PY - 2015 SN - 978-1-84973-392-2 SN - 978-1-84973-540-7 SN - 2044-253X N1 - Serientitel: New developments in mass spectrometry – Series title: New developments in mass spectrometry Das Belegexemplar liegt nur beim Autor komplett vor! VL - 3 SP - Chapter 4, 44 EP - 96 CY - Cambridge, UK AN - OPUS4-32983 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Quétel, C. A1 - Vogl, Jochen A1 - Prohaska, T. A1 - Nelms, S. A1 - Taylor, P.D.P. A1 - De Bièvre, P. T1 - Comparative performance study of ICP mass spectrometers by means of U "isotopic measurements" N2 - The performance of four commercially available ICPMS instruments of three different types was compared by means of uranium "isotopic measurements". Examined were two quadrupole sector (different generation, different manufacturer), one single detector double focusing magnetic sector and one multiple collector double focusing magnetic sector instruments. The same samples of the IRMM-072 series were used under routine conditions to measure the 233U/235U and the 233U/238U ratios which, in these samples, vary over almost three orders of magnitude from ~ 1 to ~ 2 · 10-3. Within expanded (k = 2) uncertainties, good agreement was observed between the certified values and the data internally corrected for mass-discrimination effects. The magnitude of the evaluated uncertainties was different for each type of instrument. With the multiple collector instrument, expanded uncertainties varied from - 0.04% to- 0.24% for the 233U/235U ratio, and from - 0.08% to - 0.27% for the 233U/238U ratio. They were ~ 1 to 5 times larger with the single detector magnetic sector instrument, and ~ 10 to 25 times larger with both quadrupole sector instruments. With the multiple collector instrument, repeatability of the measurements seemed to be limited by the difficulty of correcting properly for instrumental background, whereas with the single detector magnetic sector instrument the counting statistics was the only limitation (on smallest ratios). Apparent mass-discrimination was clearly found to be larger but more reproducible (and hence easier to correct for) in the case of magnetic sector instruments than for both quadrupole sector instruments. If space charge effects were the main source of mass-discrimination for all instruments, these results are in contradiction with the hypothesis of the size of mass-discrimination decreasing with the acceleration voltage. With the single detector magnetic sector instrument in particular (when operated by changing the ion energy only), our results pointed at more than only one major source of mass-discrimination, with variable size depending on the ratios measured. KW - ICP-MS KW - Isotope ratio KW - Uranium PY - 2000 DO - https://doi.org/10.1007/s002160000499 SN - 0937-0633 VL - 368 SP - 148 EP - 155 PB - Springer CY - Berlin AN - OPUS4-7218 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nelms, S. A1 - Quétel, C. A1 - Prohaska, T. A1 - Vogl, Jochen A1 - Taylor, P.D.P. T1 - Evaluation of detector dead time calculation models for ICP-MS KW - ICP-MS KW - Dead time KW - Uncertainty PY - 2001 DO - https://doi.org/10.1039/b007913h SN - 0267-9477 SN - 1364-5544 VL - 16 IS - 4 SP - 333 EP - 338 PB - Royal Society of Chemistry CY - London AN - OPUS4-7219 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Binner, Richard A1 - Homberg, U. A1 - Prohaska, S. A1 - Kalbe, Ute A1 - Witt, K. J. ED - Burns, S.E. ED - Bhatia, S.K. ED - Avila, C. M. C. ED - Hunt, B.E. T1 - Identification of descriptive parameters of the soil pore structure using experiments and CT data T2 - ICSE-5 - 5th International conference on scour and erosion CY - San Francisco, CA, USA DA - 2010-11-07 KW - Pore KW - Pore throat KW - Constriction sizes KW - CT-scan KW - Modelling PY - 2010 UR - http://books.google.de/books?id=tpyWlGWonOEC&pg=PA397&dq=Identification+of+descriptive+parameters+of+the+soil+pore+structure+using+experiments+and+CT+data&hl=de&ei=FjxBTbbiHYmbOuvQrOoB&sa=X&oi=book_result&ct=result&resnum=1&ved=0CCoQ6AEwAA#v=onepage&q=Ide SN - 978-0-7844-1147-6 N1 - Serientitel: Geotechnical Special Publication – Series title: Geotechnical Special Publication VL - 210 SP - 397 EP - 407 AN - OPUS4-23053 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Homberg, U. A1 - Binner, Richard A1 - Prohaska, S. A1 - Dercksen, V.J. A1 - Kuß, A. A1 - Kalbe, Ute ED - Witt, Karl Josef T1 - Determining geometric grain structure from X-ray micro-tomograms of gradated soil T2 - Workshop "Internal Erosion" CY - Weimar, Germany DA - 2008-11-26 KW - Gradated soil KW - Suffosive erosion phenomena KW - Pore and grain structure KW - Micro computed tomography KW - Morphologic image processing PY - 2008 SN - 978-3-86068-392-7 N1 - Serientitel: Schriftenreihe Geotechnik – Series title: Schriftenreihe Geotechnik IS - 21 SP - 37 EP - 52 PB - Bauhaus-Univ. CY - Weimar AN - OPUS4-19866 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Semar, O. A1 - Binner, Richard A1 - Homberg, U. A1 - Kalbe, Ute A1 - Mehlhorn, T. A1 - Prohaska, S. A1 - Slowik, V. A1 - Witt, K. J. ED - Witt, K. J. T1 - Conditions for suffosive erosion phenomena in soils - concept and approach - T2 - Workshop "Internal Erosion" CY - Weimar, Germany DA - 2008-11-26 KW - Pore KW - Pore throat KW - Constriction sizes KW - CT-scan KW - Modelling PY - 2008 SN - 978-3-86068-392-7 N1 - Serientitel: Schriftenreihe Geotechnik – Series title: Schriftenreihe Geotechnik IS - 21 SP - 29 EP - 35 PB - Bauhaus-Univ. CY - Weimar AN - OPUS4-19867 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paetsch, O. A1 - Baum, D. A1 - Prohaska, S. A1 - Ehrig, Karsten A1 - Meinel, Dietmar A1 - Ebell, Gino T1 - 3D corrosion detection in time-dependent CT images of concrete N2 - In civil engineering, the corrosion of steel reinforcements in structural elements of concrete bares a risk of stability-reduction, mainly caused by the exposure to chlorides. 3D computed tomography (CT) reveals the inner structure of concrete and allows one to investigate the corrosion with non-destructive testing methods. To carry out such investigations, specimens with a large artificial crack and an embedded steel rebar have been manufactured. 3D CT images of those specimens were acquired in the original state. Subsequently three cycles of electrochemical pre-damaging together with CT imaging were applied. These time series have been evaluated by means of image processing algorithms to segment and quantify the corrosion products. Visualization of the results supports the understanding of how corrosion propagates into cracks and pores. Furthermore, pitting of structural elements can be seen without dismantling. In this work, several image processing and visualization techniques are presented that have turned out to be particularly effective for the visualization and segmentation of corrosion products. Their combination to a workflow for corrosion analysis is the main contribution of this work. T2 - DIR 2015 - International symposium on digital industrial radiology and computed tomography CY - Ghent, Belgium DA - 22.06.2015 KW - Concrete KW - Corrosion detection KW - 3D computer tomography (CT) imaging KW - Image processing KW - Visualization PY - 2015 SP - 1 EP - 10 AN - OPUS4-33711 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Paetsch, O. A1 - Baum, D. A1 - Ebell, Gino A1 - Ehrig, Karsten A1 - Heyn, Andreas A1 - Meinel, Dietmar A1 - Prohaska, S. T1 - Korrosionsverfolgung in 3D-computertomographischen Aufnahmen von Stahlbetonproben N2 - Durch die Alkalität des Betons wird Betonstahl dauerhaft vor Korrosion geschützt. Infolge von Chlorideintrag kann dieser Schutz nicht länger aufrechterhalten werden und führt zu Lochkorrosion. Die zerstörungsfreie Prüfung von Stahlbetonproben mit 3D-CT bietet die Möglichkeit, eine Probe mehrfach gezielt vorzuschädigen und den Korrosionsfortschritt zu untersuchen. Zur Quanti-fizierung des Schädigungsgrades müssen die bei dieser Untersuchung anfallenden großen Bilddaten mit Bildverarbeitungsmethoden ausgewertet werden. Ein wesent-licher Schritt dabei ist die Segmentierung der Bilddaten, bei der zwischen Kor-rosionsprodukt (Rost), Betonstahl (BSt), Beton, Rissen, Poren und Umgebung unterschieden werden muss. Diese Segmentierung bildet die Grundlage für sta-tistische Untersuchungen des Schädigungsfortschritts. Hierbei sind die Änderung der BSt-Geometrie, die Zunahme von Korrosionsprodukten und deren Veränderung über die Zeit sowie ihrer räumlichen Verteilung in der Probe von Interesse. Auf-grund der Größe der CT-Bilddaten ist eine manuelle Segmentierung nicht durch-führbar, so dass automatische Verfahren unabdingbar sind. Dabei ist insbesondere die Segmentierung der Korrosionsprodukte in den Bilddaten ein schwieriges Problem. Allein aufgrund der Grauwerte ist eine Zuordnung nahezu unmöglich, denn die Grauwerte von Beton und Korrosionsprodukt unterscheiden sich kaum. Eine formbasierte Suche ist nicht offensichtlich, da die Korrosionsprodukte in Beton diffuse Formen haben. Allerdings lässt sich Vorwissen über die Ausbreitung der Korrosionsprodukte nutzen. Sie bilden sich in räumlicher Nähe des BSt (in Bereichen vorheriger Volumenabnahme des BSt), entlang von Rissen sowie in Porenräumen, die direkt am BSt und in dessen Nahbereich liegen. Davon ausgehend wird vor der Korrosionsprodukterkennung zunächst eine BSt-Volumen-, Riss- und Porenerken-nung durchgeführt. Dieser in der Arbeit näher beschriebene Schritt erlaubt es, halb-automatisch Startpunkte (Seed Points) für die Korrosionsprodukterkennung zu finden. Weiterhin werden verschiedene in der Bildverarbeitung bekannte Algorithmen auf ihre Eignung untersucht werden. T2 - DGZfP-Jahrestagung 2014 CY - Potsdam, Germany DA - 26.05.2014 KW - Korrosion KW - Corrosion KW - CT KW - Computertomographie KW - 3D KW - Stahlbeton KW - Betonstahl KW - Bewehrung KW - Lochkorrosion PY - 2014 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-325080 UR - http://jt2014.dgzfp.de/portals/jt2014/BB/di1c3.pdf SN - 978-3-940283-61-0 IS - DGZfP-BB 148 SP - Di.1.C.3, 1 EP - 10 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-32508 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Homberg, U. A1 - Baum, D. A1 - Prohaska, S. A1 - Günster, Jens A1 - Krauss-Schüler, Stefanie T1 - Adapting trabecular structures for 3D printing: an image processing approach based on μCT data N2 - Materials with a trabecular structure notably Combine advantages such as lightweight, reasonable strength, and permeability for fl uids. This combination of advantages is especially interesting for tissue engineering in trauma surgery and orthopedics. Bone-substituting scaffolds for instance are designed with a trabecular structure in order to allow cell migration for bone ingrowth and vascularization. An emerging and recently very popular technology to produce such complex, porous structures is 3D printing. However, several technological aspects regarding the scaffold architecture, the printable resolution, and the feature size have to be considered when fabricating scaffolds for bone tissue replacement and regeneration. Here, we present a strategy to assess and prepare realistic trabecular structures for 3D printing using image analysis with the aim of preserving the structural elements. We discuss critical conditions of the printing system and present a 3-stage approach to adapt a trabecular structure from μ CT data while incorporating knowledge about the printing system. In the first stage, an image-based extraction of solid and void structures is performed, which results in voxel- and graph-based representations of the extracted structures. These representations not only allow us to quantify geometrical properties such as pore size or strut geometry and length. But, since the graph represents the geometry and the topology of the initial structure, it can be used in the second stage to modify and adjust feature size, volume and sample size in an easy and consistent way. In the final reconstruction stage, the graph is then converted into a voxel representation preserving the topology of the initial structure. This stage generates a model with respect to the printing conditions to ensure a stable and controlled voxel placement during the printing process. KW - Additive manufacturing, 3D printing KW - Trabecular structures KW - Image-based analysis PY - 2017 DO - https://doi.org/10.1088/2057-1976/aa7611 SN - 2057-1976 VL - 3 IS - 3 SP - Article 035027, 1 EP - 14 PB - IOP Publishing Ltd AN - OPUS4-40744 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Ritter, Z. A1 - Staude, Andreas A1 - Prohaska, S. A1 - Felsenberg, D. ED - Naik, G. R. T1 - Osteocytes characterization using synchrotron radiation CT and finite element analysis N2 - Since a correlation between osteocyte number and their morphology with bone aging or its response to pharmacological treatment appears to exist, a methodology to characterize osteocytes from bone biopsies becomes important. In this chapter, the usage of synchrotron measurements, algorithms for image analysis (Amira, ZIB), and the finite element method using parallelized computational resources for topological analysis of osteocytes is explained and discussed. Different routines normally applied for material characterization of network-like structures (skeletonization) have been adapted to visualize osteocytes along bone cement lines at high resolution (2.174 µm). The different steps concerning to counting osteocytes and analyzing the mechanical behavior of bones are illustrated with an example. Our findings showed a clear alignment of the osteocytes along the cement lines. Interestingly, at the regions near the bone surface with reduced mineralization grade, osteocytes were mainly aligned along the close to high mineralized region. Apparently, not only osteocytes number is reduced with aging but their size increases and they become sparely distributed in comparison with the healthy bone samples from the human mandible. Automatic tetrahedron mesh generation using the "tetragen" tool from Amira worked adequately for meshing the biopsies with a resolution of 20 µm, but meshing biopsies with osteocytes embedded on the bone matrix from the SR-CT samples consumes an enormous amount of time, due to necessary adjustments for avoiding intersections and conserving model closeness. KW - CT KW - Finite element analysis KW - Osteocytes characterization KW - Synchrotron radiation PY - 2012 SN - 978-953-51-0412-4 DO - https://doi.org/10.5772/35242 SP - 165 EP - 190 PB - InTech CY - Rijeka AN - OPUS4-25845 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 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 - Homberg, U. A1 - Baum, D. A1 - Prohaska, S. A1 - Kalbe, Ute A1 - Witt, K. J. T1 - Automatic extraction and analysis of realistic pore structures from muCT data for pore space characterization of graded soil N2 - We present image-based methods to extract and analyze the pore structure of graded soil from CT scans. To assess and characterize realistic pore structures of graded soil, we process data of hetero disperse granulär material acquired via high-resolut ion CT. Real soil material configures a pore space with irregulär formations and complex arrangements. In Order to derive parameters of the pore space, a compact representation of the complex pore structure and efficient analysis methods are required. For this purpose, we propose mathematical definitions of the pore structure elements like pore centers, pore paths, pore constrictions, and pore bodies. These definitions are based on the distance map given on the Segmentation of the soil material into particles andpore space. For the extraction of the deftned structure elements, we present two image-basedprocessing pipelines that use the correspondence between our distance-based definition of pore structure elements and a Voronoi decomposition of the pore space. From the extractedpore centers andpore paths, we construct a graph and encode the distance Information on it. This graph, which we call the pore graph, is a compact 3d-representation of the topology of the pore space and provides a good basis to apply efficient graph-based methods for quantification as well as visualization and exploration of the spatial relationships and Connectivity of the pore space. T2 - ICSE6 - 6th International conference on scour and erosion CY - Paris, France DA - 27.08.2012 KW - Microtomography KW - Image analysis KW - Pore structure KW - Pore constriction KW - Suffosion KW - Graded soil PY - 2012 IS - ICSE6-181 SP - 345 EP - 352 AN - OPUS4-26965 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -