TY - CONF A1 - Meinel, Dietmar A1 - Ehrig, Karsten A1 - L' Hostis, V. A1 - Muzeau, B. A1 - Paetsch, O. T1 - Examination of Damage Processes in Concrete with CT T2 - Conference on Industrial Computed Tomography (ICT) CY - Wels, Austria DA - 2014-02-25 PY - 2014 AN - OPUS4-30310 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Brinker, U. A1 - Bērziņš, V. A1 - Ceriņa, A. A1 - Gerhards, G. A1 - Kalniņš, M. A1 - Schmölcke, U. A1 - Meinel, Dietmar A1 - Luebke, H. T1 - Two burials in a unique freshwater shell midden: insights into transformations of Stone Age hunter-fisher daily life in Latvia N2 - The Stone Age site Riņņukalns, Latvia, is the only well-stratified shell midden in the Eastern Baltic. In this paper, we present new interdisciplinary results concerning its dating, stratigraphy, features, and finds to shed light on the daily life of a fisher population prior to the introduction of domesticated animals. The undisturbed part of the midden consists of alternating layers of unburnt mussel shell, burnt mussel shell and fish bone, containing artefacts, some mammal and bird bones, and human burials. Two of them, an adult man and a baby, are discovered recently and date to the calibration plateau between 3350 and 3100 cal BC, and to the later 4th millennium, respectively. Stable isotopes suggest a diet based heavily on freshwater fish, and this is supported not only by ten thousands of identified fish remains, but also by a fish bone concentration nearby the skull of the man, which is interpreted as remain of a grave gift (possible fish soup). Of special interest are the baby’s stable isotope values. It shows that the mother’s diet was atypical (perhaps because she was non-local), and/or that dietary stress during pregnancy increased fractionation between the mother’s diet and her bloodstream KW - Baltic Stone Age KW - Palaeoanthropology PY - 2020 U6 - https://doi.org/10.1007/s12520-020-01049-7 VL - 12 IS - 5 SP - Article number: 97 PB - Springer-Verlag GmbH CY - Germany AN - OPUS4-50653 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Illemann, J. A1 - Meinel, Dietmar A1 - Bellon, Carsten T1 - Effektive Bestimmung der Fokusparameter von Mikrofokus-Röntgenquellen N2 - Mikrofokus-Röntgenquellen werden in der industriellen CT flexibelverwendet, um mit kleiner Leistung hohe Auflösung zu erzielen oder mit verminderter Auflösung bei höherer Leistung kürzere Messzeiten zu erreichen. Insbesondere Quellen in offener Bauweise benötigen Wartung wie Filamentwechsel und Nachstellen der Fokusparameter. Ziel ist es, einen optimal kleinen Quellfleck bei bekannter Spannung einzustellen und dessen Größe zu bestimmen. Zur Überprüfung der Quellfleckgröße sind bereits Verfahren unter Verwendung lithographisch hergestellter Masken mit Strichmustern oder Siemenssternen aus Mikrometer dünnen Schichten aus stark absorbierendem Material wie z.B. Gold bekannt. Diese erfordern wegen der geringen Absorption eine lange Messzeit und sind nur kostenintensiv herzustellen. Ihre Verwendung zur regelmäßigen Qualitätsüberprüfung von CT-Anlagen ist daher nicht verbreitet. Ziel dieser Arbeit ist es, die richtungsabhängige Quellfleckgröße absolut zu bestimmen, wobei nur einfach zu beschaffende Wolframspitzen verwendet werden. Dazu werden radiographische Bilder in hoher Vergrößerung aufgenommen und die Grauwertverteilung parametrisiert. Unter Verwendung der Kenntnis von Targetmaterial und Spannung wird eine eineindeutige Zuordnung zur Quellfleckgröße vorgenommen. Dieses erfordert eine extensive Simulation für verschiedene Spannungen, Fokusgrößen und andere Einflussgrößen, sowie die experimentelle Verifikation an verschiedenen CT-Anlagen im Vergleich zu einer bekannten Methode. Erste Ergebnisse werden vorgestellt und die praktische Implementierung unter Angabe der Einschränkungen der Verwendbarkeit diskutiert. Die Autoren hoffen, damit einen wesentlichen Beitrag zur Verbesserung der Qualitätssicherung und zur Arbeitseffizienz in der Mikrocomputertomographie leisten zu können. T2 - DGZfP DACH-Jahrestagung 2019 CY - Friedrichshafen, Germany DA - 27.05.2019 KW - Mikro-Computertomographie KW - Röntgenröhre KW - Quellfleckgröße KW - Brennfleck PY - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:b43-485960 UR - https://www.ndt.net/search/docs.php3?id=24551 UR - https://www.ndt.net/article/dgzfp2019/papers/Mi.2.A.3.pdf IS - NDT.net Issue: 2019-08 SP - 1 EP - 13 AN - OPUS4-48596 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Andrade, C. A1 - Saucedo, L. A1 - Rebolledo, N. A1 - Cabeza, S. A1 - Meinel, Dietmar T1 - X-Ray computed tomography and traditional analysis of a capillary absorption test in cement pastes N2 - Water absorption testing has the attraction of being simple, relatively quick and use water as a fluid which is the key substance in the possible concrete deterioration. However, in spite of the advantages its application has remained empirical, except for the testing of resistance to frost, through the identification of the critical degree of saturation. Rilem TC-116 studied this test, among others, for the characterization of concrete resistance against transport through the concrete pore network. Results indicated a low discriminating ability of the absorbency for qualifying concrete resistance and then, it seemed necessary to try to move forward by making the link between the absorption testing and the concrete pore microstructure. In the present work, thanks to the X-Ray computed tomography, it is described the evolution of the water front in three paste-specimen with different w/c ratios (different pore radius distributions). The observations allowed us to deduce that all the pores start to fill simultaneously, but the bigger ones fill quicker and rise less. The saturation degree is measured along the height of the sample, showing that each pore size has a different rate which becomes constant after the first hour. Washburn’s equation was applied to the progressive advance of the water front, resulting in a pore radius much smaller than the one expected. KW - Capillary absorption KW - Pore size distribution KW - X-ray CT KW - Gravimetry PY - 2020 U6 - https://doi.org/10.1016/j.cemconcomp.2020.103634 VL - 113 SP - 103634 PB - Elsevier Ltd. CY - London AN - OPUS4-51487 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silva, W. A1 - Lopes, R. A1 - Zscherpel, Uwe A1 - Meinel, Dietmar A1 - Ewert, Uwe T1 - X-ray imaging techniques for inspection of composite pipelines N2 - The literature has shown that the application of laminography provides advantages as 3D radiographic imaging with depth information for in house and mobile testing. This permits to distinguish between overlapping indications, measure the extension along radiation direction and classify indications as surface open or subsurface ones as required in critical engineering assessment. This work provides a comparative study and measurements of the three techniques Digital Radiography (DR) with Digital Detector Arrays (DDA), Coplanar Translational Laminography (CTL) and Computed Tomography (CT), applied for composite pipeline inspection. It is demonstrated that CTL and CT provide advantages for the evaluation of pipe-to-pipe connections and the evaluation of adhesive applications. They show indications of discontinuities with higher contrast sensitivity than radiography. Beyond it, two specimen, namely Phantom 1 and Phantom 2, were developed and manufactured by additive manufacturing to analyze the preferential detection sensitivity and the direction of features and depth information for laminographic measurements. Another goal was to show the laminographic capabilities to distinguish between overlapping discontinuities. CTL is especially suitable for mobile inspection. Special glass fiber reinforced polymer samples (GRP) were manufactured for further analysis and comparisons between the abovementioned techniques. Finally, Phantoms 1 and 2 show the capability of laminography to detect overlapping indications and also show that discontinuities oriented perpendicular to the scan direction have the highest contrast sensitivity for laminographic measurements. KW - Digital Radiography KW - Laminography KW - Computed Tomography KW - Composite Pipes KW - Image Quality PY - 2021 U6 - https://doi.org/10.1016/j.micron.2021.103033 SN - 0968-4328 VL - 145 SP - 103033 PB - Elsevier Ltd. AN - OPUS4-52415 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Myrach, Philipp A1 - Jonietz, Florian A1 - Meinel, Dietmar A1 - Suwala, Hubert A1 - Ziegler, Mathias T1 - Calibration of thermographic spot weld testing with X-ray computed tomography N2 - The paper presents an attempt for the calibration of an active thermography method that is suitable for the non-destructive evaluation of spot welds. Nowadays, the quality of spot welds is commonly characterised by the application of random chisel tests, which are time consuming, expensive and destructive. Recently a non-destructive testing method by means of active thermography was proposed that relies on the fact that the mechanical connection formed by the spot weld also serves as a thermal bridge between the two steel sheets joined in the welding process. It is shown in this paper that this thermal bridge can be thermographically characterised by extracting a measure for the spot weld diameter and hence the quality of the spot weld. The determination of the absolute value of the diameter hereby relies on a calibration of the testing system, which is performed by means of X-ray computed tomography in this study. The experiments were carried out using different experimental approaches, namely transmission as well as reflection geometry wSetup in reflectionith laser illumination. A comprehensive evaluation of samples produced using different welding currents, hence different quality, was carried out in order to validate the thermographic results. KW - Thermography KW - Spot welds KW - Spot welding KW - Computed thomography KW - Non-destructive testing PY - 2017 U6 - https://doi.org/10.1080/17686733.2017.1281554 SN - 1768-6733 SN - 2116-7176 VL - 14 IS - 1 SP - 122 EP - 131 PB - Taylor & Francis CY - London AN - OPUS4-40180 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pulikowski, D. A1 - Lackner, F. A1 - Scheuerlein, C. A1 - Meinel, Dietmar A1 - Savary, F. A1 - Tommasini, D. A1 - Pajor, M. T1 - Testing mechanical behavior of Nb3Sn Rutherford cable during coil winding N2 - In the framework of the development of high field magnets made of Nb3Sn superconductor for projects like HL-LHC and FCC studies, it is needed to refine the understanding of the coil winding process and its impact on the overall mechanical behavior of the conductor. For this purpose, a new cable winding setup has been developed in order to compare the windability of different Nb3Sn Rutherford cables. In addition, various geometrical cable inspection methods were tested and compared. First experimental results obtained with the new set-up for winding tests are summarized. T2 - 2016 Applied Superconductivity Conference (ASC’16) CY - Denver, Colorado, USA DA - 04.09.2016 KW - Coil winding KW - Rutherford cable KW - X-ray absorption tomography PY - 2017 U6 - https://doi.org/10.1109/TASC.2017.2656179 SN - 1051-8223 SN - 1558-2515 VL - 27 IS - 4 SP - 1 EP - 4 PB - IEEE AN - OPUS4-39357 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hüsken, Götz A1 - Pirskawetz, Stephan A1 - Meinel, Dietmar ED - Banjad Pecur, Ivana ED - Baricevic, Ana ED - Stirmer, Nina ED - Bjegovic, Dubravka T1 - Experimental characterization of the fracture behavior of UHPFRC N2 - Ultra-high performance fiber-reinforced concretes (UHPFRCs) are most suitable for applications with extreme mechanical loads. These extreme conditions require ductile behavior under tensile loading, which is obtained solely by the working mechanism of steel fibers. Profound knowledge on the working mechanism of the steel fibers is necessary to optimize this material. Usually, this knowledge is obtained by means of classical destructive measuring techniques. Adopting measuring techniques from non-destructive material testing helps to analyze and to identify the different stages of the fracture mechanism of UHPFRC in detail. The application of different non-destructive measuring techniques is shown exemplary on tensile tests conducted on an UHPFRC mix and its applicability for analyzing the fracture behavior of such concretes is discussed. The main focus is on the characterization of the relevant failure modes under tensile loading by the different measuring techniques and the comparison with classical measuring techniques (e.g. extensometer). The tensile tests have been analyzed by optical deformation measurements using digital image correlation (DIC), acoustic emission analysis (AE), and 3D computed tomography (CT). T2 - 1st International Conference on Construction Materials for Sustainable Future (CoMS_2017) CY - Zadar, Croatia DA - 19.04.2017 KW - UHPFRC KW - Tensile strength KW - Acoustic emission analysis KW - Optical deformation measurement KW - 3D computed tomography PY - 2017 SN - 978-953-8168-04-8 SP - 293 EP - 299 AN - OPUS4-39910 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Meinel, Dietmar A1 - Willer, F. ED - Fitzenreiter, M. ED - Willer, F. ED - Auenmüller, J. T1 - Röntgen-Mikro-Computertomographie (µCT) - Virtuelle Freilegung innenliegender Strukturen N2 - Im Frühjahr 1969 wurde bei Ausgrabungen der Universität Bonn unter Leitung von Elmar Edel auf der Qubbet el-Hawa ein außergewöhnliches Depot mit Materialien einer antiken Gusswerkstatt gefunden. Im Zuge der Fundteilung gelangten die meisten Stücke des Konvolutes in das Ägyptische Museum der Universität Bonn und werden dort aufbewahrt. Die Deponierung des für die Forschung zur antiken Metallurgie bisher einzigartigen Konvoluts geschah im Zuge der Nachnutzung von Grabanlagen aus dem Alten Reich (um 2100 v. u. Z.) in der ägyptischen Spätzeit (um 550 – 400 v. u. Z.). Das Depot enthält Objekte, die alle Fertigungsstufen von Metallgegenständen im Wachsausschmelzverfahren dokumentieren. Es wurden Stücke von Rohwachs sowie Wachsmodelle und die zu deren Herstellung genutzten Negativformen gefunden. Weiterhin enthielt es vollständige Gussformen, die in einem aufwendigen Mehrschalenverfahren hergestellt wurden und teilweise bereits für den Guss ausgebrannt worden sind. Schließlich zählen einige Metallfiguren sowie weitere figürliche Objekte zum Konvolut, die alle in den Bereich einer kunsthandwerklichen Werkstatt deuten. Eine Besonderheit stellen zudem Gussformen dar, in denen Fragmente von Metallfiguren zur Reparatur im Überfangguss vorbereitet waren. Das Depot wurde in der Gesamtpublikation der Bonner Grabungen bisher nur summarisch vorgestellt. 2014/15 initiierten die Abteilung Ägyptologie der Universität Bonn und das LVR-LandesMuseum Bonn unter Ludwig D. Morenz und Michael Schmauder ein gemeinsames und von der Fritz-Thyssen-Stiftung gefördertes Forschungsprojekt, das von Martin Fitzenreiter, Johannes Auenmüller und Frank Willer geleitet wurde. In Kooperation mit Dietmar Meinel (Bundesanstalt für Materialforschung und -prüfung Berlin / BAM, Fachbereich 8.5 Mikro-ZfP), Roland Schwab (Curt-Engelhorn-Zentrum Archäometrie gGmbH, Mannheim), Gerwulf Schneider (FU Berlin, Exzellenzcluster TOPOI), Ursula Baumer und Patrick Dietemann (beide Doerner-Institut / München), Thorsten Geisler-Wierwille (Steinmann Institut für Geologie, Mineralogie und Paläontologie der Universität Bonn) sowie Ursula Tegtmeier (Labor für Archäobotanik der Universität Köln) wurden die Objekte des Konvolutes eingehend und mit zeitgemäßen Verfahren untersucht. Die Ergebnisse dieses Forschungsprojekts werden in dieser Publikation vorgelegt. KW - Mikro-CT KW - Bronzeguss KW - Digitale Bildverarbeitung PY - 2016 SN - 978-3-86893-225-6 SP - 82 EP - 117 PB - EB-Verlag CY - Berlin AN - OPUS4-39208 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Meinel, Dietmar T1 - Computertomographie in der BAM N2 - Überblicksvortrag über die Aktivitäten des FB 8.5 im Bereich der industriellen Computertomographie T2 - 6. Geo-CT / Imaging Workshop CY - Institut für Geowissenschaften, Jena, Germany DA - 10.11.2016 KW - Mikro-CT KW - Synchrotron CT KW - In-situ 3D-CT PY - 2016 AN - OPUS4-39209 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -