TY - JOUR A1 - Natsopoulou, M. E. A1 - McMahon, Dino Peter A1 - Doublet, V. A1 - Frey, E. A1 - Rosenkranz, P. A1 - Paxton, R. J. T1 - The virulent, emerging genotype B of Deformed wing virus is closely linked to overwinter honeybee worker loss N2 - Bees are considered to be threatened globally, with severe overwinter losses of the most important commercial pollinator, the Western honeybee, a major concern in the Northern Hemisphere. Emerging infectious diseases have risen to prominence due to their temporal correlation with colony losses. Among these is Deformed wing virus (DWV), which has been frequently linked to colony mortality. We now provide evidence of a strong statistical association between overwintering colony decline in the field and the presence of DWV genotype-B (DWV-B), a genetic variant of DWV that has recently been shown to be more virulent than the original DWV genotype-A. We link the prevalence of DWV-B directly to a quantitative measure of overwinter decline (workforce mortality) of honeybee colonies in the field. We demonstrate that increased prevalence of virus infection in individual bees is associated with higher overwinter mortality. We also observed a substantial reduction of infected colonies in the spring, suggesting that virus-infected individuals had died during the winter. Our findings demonstrate that DWV-B, plus possible A/B recombinants exhibiting DWV-B at PCR primer binding sites, may be a major cause of elevated overwinter honeybee loss. Its potential emergence in naïve populations of bees may have far-reaching ecological and economic impacts. KW - Honeybee KW - Loss KW - Virulence KW - Virus PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410446 DO - https://doi.org/10.1038/s41598-017-05596-3 SN - 2045-2322 IS - 7 SP - 5242, 1 EP - 5242, 9 AN - OPUS4-41044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wesch, Ch. A1 - Elert, Anna Maria A1 - Wörner, M. A1 - Braun, Ulrike A1 - Klein, R. A1 - Paulus, M. T1 - Assuring quality in microplastic monitoring: About the value of clean-air devices as essentials for verified data N2 - Avoiding aerial microfibre contamination of environmental samples is essential for reliable analyses when it comes to the detection of ubiquitous microplastics. Almost all laboratories have contamination problems which are largely unavoidable without investments in clean-air devices. Therefore, our study supplies an approach to assess background microfibre contamination of samples in the laboratory under particle-free air conditions. We tested aerial contamination of samples indoor, in a mobile laboratory, within a laboratory fume hood and on a clean bench with particles filtration during the examining process of a fish. The used clean bench reduced aerial microfibre contamination in our laboratory by 96.5%. This highlights the value of suitable clean-air devices for valid microplastic pollution data. Our results indicate, that pollution levels by microfibres have been overestimated and actual pollution levels may be many times lower. Accordingly, such clean-air devices are recommended for microplastic laboratory applications in future research work to significantly lower error rate KW - Microplastics KW - FTIR KW - Quality KW - Environmental Science KW - Biological techniques PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-412402 DO - https://doi.org/10.1038/s41598-017-05838-4 SN - 2045-2322 VL - 7 SP - Article 5424, 1 EP - 8 PB - Nature AN - OPUS4-41240 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Naresh-Kumar, G. A1 - Vilalta-Clemente, A. A1 - Jussila, H. A1 - Winkelmann, Aimo A1 - Nolze, Gert A1 - Vespucci, S. A1 - Nagarajan, S. A1 - Wilkinson, A. J. A1 - Trager-Cowan, C. T1 - Quantitative imaging of anti-phase domains by polarity sensitive orientation mapping using electron backscatter diffraction N2 - Advanced structural characterisation techniques which are rapid to use, non-destructive and structurally definitive on the nanoscale are in demand, especially for a detailed understanding of extended-defects and their influence on the properties of materials. We have applied the electron backscatter diffraction (EBSD) technique in a scanning electron microscope to non-destructively characterise and quantify antiphase domains (APDs) in GaP thin films grown on different (001)Si substrates with different offcuts. We were able to image and quantify APDs by relating the asymmetrical intensity distributions observed in the EBSD patterns acquired experimentally and comparing the same with the dynamical electron diffraction simulations. Additionally mean angular error maps were also plotted using automated cross-correlation based approaches to image APDs. Samples grown on substrates with a 4° offcut from the [110] do not show any APDs, whereas samples grown on the exactly oriented substrates contain APDs. The procedures described in our work can be adopted for characterising a wide range of other material systems possessing non-centrosymmetric point groups. KW - Polarity KW - Semiconductor KW - Antiphase boundary PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420167 SN - 2045-2322 VL - 7 SP - Article 10916, 1 EP - 10 AN - OPUS4-42016 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Luong, Thi Mai Hoa A1 - Zabel, V. A1 - Lorenz, W. A1 - Rohrmann, R.G. T1 - Non-destructive assessment of the axial stress state in iron and steel truss structures by dynamic measurements N2 - This paper is concerned with the inverse identification of the stress state in axially loaded slender members of iron and steel truss structures using measured dynamic data. A methodology is proposed based on the finite element model updating coupled with nature-inspired optimization techniques, in particular the particle swarm optimization. The numerical model of truss structures is calibrated using natural frequencies and mode shapes from vibration tests, as well as additional information of the axial forces in selected truss members based on the experimentally identified modal parameters. The results of the identification are the axial forces or corresponding stresses in truss structures and the joint rigidity in relation to pinned and rigid conditions. Attention is given to several examined aspects, including the effects of the axial tensile and compressive forces on the dynamic responses of trusses, mode pairing criteria, as well as modeling assumptions of joints and the use of a joint rigidity parameter. Considering the pairing of modes, it is performed by adapting an enhanced modal assurance criterion that allows the selection of desired clusters of degrees-of-freedom. Thus, information extracted from the measurements related to specific modes is utilized in a more beneficial way. For modeling of joints, the numerical model of a truss structure includes rotational springs of variable stiffness to represent semi-rigid connections. Moreover, a fixity factor is introduced for practical estimation of the joint flexibility. The effectiveness of the proposed methodology is demonstrated by case studies involving simulated and laboratory experimental data. T2 - X International Conference on Structural Dynamics, EURODYN 2017 DA - 10.09.2017 KW - Axial force KW - Dynamic test KW - Model updating KW - Optimization technique KW - Truss structures KW - Modal parameters PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419311 DO - https://doi.org/10.1016/j.proeng.2017.09.447 SN - 1877-7058 VL - 199 SP - 3380 EP - 3385 PB - Elsevier AN - OPUS4-41931 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stajanca, Pavol A1 - Krebber, Katerina T1 - Radiation-induced attenuation of perfluorinated polymer optical fibers for radiation monitoring N2 - Due to some of their unique properties, optical fiber dosimeters are attractive and extensively researched devices in several radiation-related areas. This work evaluates the Performance and potential of commercial perfluorinated polymer optical fibers (PF-POFs) for radiation Monitoring applications. Gamma radiation-induced attenuation (RIA) of two commercial PF-POFs is evaluated in the VIS spectral region. Influence of a dose rate and temperature on RIA measurement is investigated, along with defect stability and measurement repeatability. Co-extruded PF-POFs are identified as more suitable for radiation monitoring applications due to lower dose-rate dependence. With co-extruded PF-POF, RIA measurement holds potential for highly-sensitive radiation Monitoring with good reproducibility. The results show that operation in the blue part of the spectrum provides most favorable performance in terms of the largest nominal Radiation sensitivity, lower temperature, and dose-rate dependence as well as higher defect stability. We demonstrate for the first time to our knowledge, that PF-POFs can be used for distributed detection of radiation with doses down to tens of Grays. The off-the-shelf, user-friendly PF-POF could be of interest as a cheap, disposable sensor for various applications, especially of a more qualitative nature. KW - Perfluorinated polymer optical fiber KW - Cytop KW - Ionizing radiation KW - Radiation-induced attenuation KW - Gamma radiation monitoring PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419504 DO - https://doi.org/10.3390/s17091959 SN - 1424-8220 VL - 17 IS - 9 SP - Article 1959, 1 EP - 12 PB - MDPI AN - OPUS4-41950 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kömmling, Anja A1 - Chatzigiannakis, E. A1 - Beckmann, Jörg A1 - Wachtendorf, Volker A1 - von der Ehe, Kerstin A1 - Braun, Ulrike A1 - Jaunich, Matthias A1 - Schade, U. A1 - Wolff, Dietmar T1 - Discoloration Effects of High-Dose gamma-Irradiation and Long-Term Thermal Aging of (U) HMW-PE N2 - Two polyethylene types with ultra-high (UHMWPE) and high molecular weight (HMW-PE) used as neutron radiation shielding materials in casks for radioactive waste were irradiated with doses up to 600 kGy using a 60Co gammasource. Subsequently, thermal aging at 125∘C was applied for up to one year. Degradation effects in the materials were characterized using colorimetry, UV-Visspectroscopy, IR spectroscopy, and DSC. Both materials exhibited a yellowing upon irradiation.The discoloration of UHMW-PE disappeared again after thermal aging.Therefore, the yellowing is assumed to originate fromannealable color centers in the formof free radicals that are trapped in the crystalline regions of the polymer and recombine at elevated temperatures. For the antioxidantcontaining HMWPE, yellowing was observed after both irradiation and thermal aging. The color change was correlated mainly to decomposition products of the antioxidant in addition to trapped radicals as in UHMW-PE. Additionally, black spots appeared after thermal aging of HMW-PE. KW - Irradiation KW - UHMWPE KW - Colour center KW - Yellowness index PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-423992 DO - https://doi.org/10.1155/2017/1362491 SN - 1687-9422 VL - 2017 IS - Article ID 1362491 SP - 1 EP - 10 PB - Hindawi AN - OPUS4-42399 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Le, Quynh Hoa A1 - Vestergaard, M.C. A1 - Tamiya, E T1 - Carbon-based nanomaterials in biomass-based fuel-fed fuel cells N2 - Environmental and sustainable economical concerns are generating a growing interest in biofuels predominantly produced from biomass. It would be ideal if an energy conversion device could directly extract energy from a sustainable energy resource such as biomass. Unfortunately, up to now, such a direct conversion device produces insufficient power to meet the demand of practical applications. To realize the future of biofuel-fed fuel cells as a green energy conversion device, efforts have been devoted to the development of carbon-based nanomaterials with tunable electronic and surface characteristics to act as efficient metal-free electrocatalysts and/or as supporting matrix for metal-based electrocatalysts. We present here a mini review on the recent advances in carbon-based catalysts for each type of biofuel-fed/biofuel cells that directly/indirectly extract energy from biomass resources, and discuss the challenges and perspectives in this developing field KW - Carbon-based nanomaterials KW - Biofuel cells KW - Biomass KW - Carbon nanotubes KW - Graphene KW - Carbon nanodots PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428226 UR - http://www.mdpi.com/1424-8220/17/11/2587/htm DO - https://doi.org/10.3390/s17112587 SN - 1424-8220 VL - 17 IS - 11 SP - 2587, 1 EP - 2587, 21 PB - MDPI AG CY - Basel, Switzerland AN - OPUS4-42822 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heitz, J. A1 - Plamadeala, C. A1 - Muck, M. A1 - Armbruster, O. A1 - Baumgartner, W. A1 - Weth, A. A1 - Steinwender, C. A1 - Plessberger, H. A1 - Kellermair, J. A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Guntner, A. S. A1 - Hassel, A. W. T1 - Femtosecond laser-induced microstructures on Ti substrates for reduced cell adhesion N2 - Miniaturized pacemakers with a surface consisting of a Ti alloy may have to be removed after several years from their implantation site in the heart and shall, therefore, not be completely overgrown by cells or tissue. A method to avoid this may be to create at the surface by laser-ablation self-organized sharp conical spikes, which provide too little surface for cells (i.e., fibroblasts) to grow on. For this purpose, Ti-alloy substrates were irradiated in the air by 790 nm Ti:sapphire femtosecond laser pulses at fluences above the ablation threshold. The laser irradiation resulted in pronounced microstructure formation with hierarchical surface morphologies. Murine fibroblasts were seeded onto the laser-patterned surface and the coverage by cells was evaluated after 3–21 days of cultivation by means of scanning electron microscopy. Compared to flat surfaces, the cell density on the microstructures was significantly lower, the coverage was incomplete, and the cells had a clearly different morphology. The best results regarding suppression of cell growth were obtained on spike structures which were additionally electrochemically oxidized under acidic conditions. Cell cultivation with additional shear stress could reduce further the number of adherent cells. KW - Laser Processing KW - Femtosecond laser KW - Titanium alloy KW - Cell adhesion KW - Anodic oxidation KW - Pacemaker PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427681 UR - https://link.springer.com/article/10.1007/s00339-017-1352-0 DO - https://doi.org/10.1007/s00339-017-1352-0 SN - 0947-8396 SN - 1432-0630 VL - 123 IS - 12 SP - 734, 1 EP - 9 PB - Springer-Verlag CY - Berlin AN - OPUS4-42768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jonietz, Florian A1 - Krankenhagen, Rainer A1 - Noack, M. A1 - Gensecke, K. A1 - Wiedenmann, E. T1 - 3D-Formbestimmung mit integrierter thermografischer Qualitätsprüfung N2 - Sowohl die 3D-Formbestimmung als auch die Thermografie sind Verfahren der Qualitätssicherung. Im vorgestellten Projekt wird versucht, die beiden Methoden zusammenzuführen. Das Prinzip des für die Formbestimmung verwendeten 3D-Scanners beruht auf dem bereits bekannten Verfahren der Streifenlichtprojektion. Die Neuartigkeit des hier verwendeten 3D-Scanners besteht darin, dass nicht im sichtbaren, sondern im infraroten Spektralbereich gearbeitet wird. Dadurch wird es möglich, nicht die Reflexion, sondern die Wärmestrahlung des Prüfobjektes nach Absorption der eingebrachten Strahlung auszuwerten. Dies ermöglicht, auch optisch „nicht-kooperative“ Oberflächen zu erfassen. Die Anregung mit Wärmestrahlung stellt das Bindeglied zum Verfahren der aktiven Thermografie für die Detektion verdeckter Schäden dar. Bei letzterem Verfahren wird der Wärmestau über Defekten beim Eindringen der Wärme in die Tiefe des Materials gemessen. Dabei stellen Defekte eine Störung des 3D-Scan-Verfahrens dar, während umgekehrt unregelmäßig geformte Oberflächen das thermografische Verfahren erschweren, d.h. der Messeffekt eines der Verfahren ist ein Störeffekt für das jeweils andere Verfahren. Es wird zum einen der Frage nachgegangen, inwieweit das 3D-Scan-Verfahren durch verdeckte thermische Defekte beeinträchtigt wird, und zum anderen die Möglichkeit untersucht, den vorhandenen 3D-Scanner auch für die aktive Thermografie einzusetzen. Es werden CFK-Proben mit künstlich eingebrachten thermischen Defekten untersucht und die Möglichkeiten und Grenzen der vorhandenen Messapparatur für die Defekterkennung aufgezeigt. T2 - DGZfP-Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - 3D-Formbestimmung KW - Thermografische Qualitätsprüfung KW - Streifenlichtprojektion KW - 3D-Scanner KW - Aktive Thermografie PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-407856 UR - https://jahrestagung.dgzfp.de/Portals/151//doc/Mi.1.A.3.pdf SN - 978-3-940283-85-6 VL - 162 SP - 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-40785 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Daly, M. A1 - Burnett, T. L. A1 - Pickering, E. J. A1 - Tuck, O. C. G. A1 - Léonard, Fabien A1 - Kelley, R. A1 - Withers, P. J. A1 - Sherry, A. H. T1 - A multi-scale correlative investigation of ductile fracture N2 - The use of novel multi-scale correlative methods, which involve the coordinated characterisation of matter across a range of length scales, are becoming of increasing value to materials scientists. Here, we describe for the first time how a multi-scale correlative approach can be used to investigate the nature of ductile fracture in metals. Specimens of a nuclear pressure vessel steel, SA508 Grade 3, are examined following ductile fracture using medium and high-resolution 3D X-ray computed tomography (CT) analyses, and a site-specific analysis using a dual beam plasma focused ion beam scanning electron microscope (PFIB-SEM). The methods are employed sequentially to characterise damage by void nucleation and growth in one volume of interest, allowing for the imaging of voids that ranged in size from less than 100 nm to over 100 mm. This enables the examination of voids initiated at carbide particles to be detected, as well as the large voids initiated at inclusions. We demonstrate that this multi-scale correlative approach is a powerful tool, which not only enhances our understanding of ductile failure through detailed characterisation of microstructure, but also provides quantitative information about the size, volume fractions and spatial distributions of voids that can be used to inform models of failure. It isfound that the vast majority of large voids nucleated at MnS inclusions, and that the volume of a void varied according to the volume of its initiating inclusion raised to the power 3/2. The most severe voiding was concentrated within 500 mm of the fracture surface, but measurable damage was found to extend to a depth of at least 3 mm. Microvoids associated with carbides (carbide-initiated voids) were found to be concentrated around larger inclusion-initiated voids at depths of at least 400 mm. Methods for quantifying X-ray CT void data are discussed, and a procedure for using this data to calibrate parameters in the Gurson-Tvergaard Needleman (GTN) model for ductile failure is also introduced. KW - Gurson model KW - SA508 KW - Correlative tomography KW - Void nucleation & growth KW - X-ray computed tomography PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-414547 UR - http://www.sciencedirect.com/science/article/pii/S1359645417302203?via%3Dihub DO - https://doi.org/10.1016/j.actamat.2017.03.028 VL - 130 SP - 56 EP - 68 PB - Elsevier AN - OPUS4-41454 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tatzel, Michael A1 - von Blanckenburg, F. A1 - Oelze, M. A1 - Bouchez, J. A1 - Hippler, D. T1 - Late Neoproterozoic seawater oxygenation by siliceous sponges N2 - The Cambrian explosion, the rapid appearance of most animal phyla in the geological record, occurred concurrently with bottom seawater oxygenation. Whether this oxygenation Event was triggered through enhanced nutrient supply and organic carbon burial forced by increased continental weathering, or by species engaging in ecosystem engineering, remains a fundamental yet unresolved question. Here we provide evidence for several simultaneous developments that took place over the Ediacaran–Cambrian transition: expansion of siliceous sponges, decrease of the dissolved organic carbon pool, enhanced organic carbon burial, increased phosphorus removal and seawater oxygenation. This evidence is based on Silicon and carbon stable isotopes, Ge/Si ratios, REE-geochemistry and redox-sensitive elements in a chert-shale succession from the Yangtze Platform, China. According to this reconstruction, sponges have initiated seawater oxygenation by redistributing organic carbon oxidation through filtering suspended organic matter from seawater. The resulting increase in dissolved oxygen levels potentially triggered the diversification of eumetazoans. KW - Oxygenation KW - Carbon cycle KW - Silicon stable isotopes PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422339 DO - https://doi.org/10.1038/s41467-017-00586-5 SN - 2041-1723 VL - 8 SP - Article 621, 1 EP - 10 AN - OPUS4-42233 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Stengel, Dominik A1 - Thiele, K. T1 - Measurements of downburst wind loading acting on an overhead transmission line in Northern Germany N2 - Along an overhead transmission line in Northern Germany, a unique instrumentation of anemometers and force measurements is installed. Details of this test line with wind measurements along a horizontal axis are given. A recent event of a presumable downburst wind event is analyzed by means of available data and precedent works on thunderstorm analysis. The measured response of the conductors at the suspension tower is investigated and compared with time domain simulation of a finite element model. T2 - X International Conference on Structural Dynamics, EURODYN 2017 CY - Rome, Italy DA - 10.09.2017 KW - Non-synoptic wind event KW - Downburst KW - Overhead transmission line KW - Finite element method PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-421239 DO - https://doi.org/10.1016/j.proeng.2017.09.578 SN - 1877-7058 VL - 199 IS - Supplement C SP - 3152 EP - 3157 PB - Elsevier AN - OPUS4-42123 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Winkelmann, Aimo A1 - Nolze, Gert A1 - Vespucci, S. A1 - Gunsekar, N.-K. A1 - Trager-Cowan, C. A1 - Vilalta-Clemente, A. A1 - Wilkinson, A. J. A1 - Voss, M. T1 - Diffraction effects and inelastic electron transport in angle-resolved microscopic imaging applications N2 - We analyse the signal formation process for scanning electron microscopic imaging applications on crystalline specimens. In accordance with previous investigations, we find nontrivial effects of incident beam diffraction on the backscattered electron distribution in energy and momentum. Specifically, incident beam diffraction causes angular changes of the backscattered electron distribution which we identify as the dominant mechanism underlying pseudocolour orientation imaging using multiple, angle-resolving detectors. Consequently, diffraction effects of the incident beam and their impact on the subsequent coherent and incoherent electron transport need to be taken into account for an in-depth theoretical modelling of the energy- and momentum distribution of electrons backscattered from crystalline sample regions. Our findings have implications for the level of theoretical detail that can be necessary for the interpretation of complex imaging modalities such as electron channelling contrast imaging (ECCI) of defects in crystals. If the solid angle of detection is limited to specific regions of the backscattered electron momentum distribution, the image contrast that is observed in ECCI and similar applications can be strongly affected by incident beam diffraction and topographic effects from the sample surface. As an application, we demonstrate characteristic changes in the resulting images if different properties of the backscattered electron distribution are used for the analysis of a GaN thin film sample containing dislocations. KW - EBSD KW - Channeling-in KW - Background processing KW - Center of mass KW - Backscattered electrons PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422063 DO - https://doi.org/10.1111/jmi.12571 SN - 0022-2720 VL - 267 IS - 3 SP - 330 EP - 346 PB - Wiley & Sons, Ltd. AN - OPUS4-42206 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Łojewska, J. A1 - Rabin, Ira A1 - Pawcenis, D. A1 - Bagniuk, J. A1 - Aksamit-Koperska, M.-A. A1 - Sitarz, M. A1 - Missori, M. A1 - Krutzsch, M. T1 - Recognizing ancient papyri by a combination of spectroscopic, diffractional and chromatographic analytical tools N2 - Ancient papyri are a written heritage of culture that flourished more than 3000 years ago in Egypt. One of the most significant collections in the world is housed in the Egyptian Museum and Papyrus Collection in Berlin, from where the samples for our investigation come. The papyrologists, curators and conservators of such collections search intensely for the analytical detail that would allow ancient papyri to be distinguished from modern fabrications, in order to detect possible forgeries, assess papyrus deterioration state, and improve the design of storage conditions and conservation methods. This has become the aim of our investigation. The samples were studied by a number of methods, including spectroscopic (FTIR, fluorescent-FS, Raman) diffractional (XRD) and chromatographic (size exclusion chromatography-SEC), selected in order to determine degradation parameters: overall oxidation of lignocellulosic material, degree of polymerization and crystallinity of cellulose. The results were correlated with those obtained from carefully selected model samples including modern papyri and paper of different composition aged at elevated temperature in humid air. The methods were classified in the order SEC > FS > FTIR > XRD, based on their effectiveness in discriminating the state of papyri degradation. However, the most trustworthy evaluation of the age of papyri samples should rely on several methods. KW - Archaeometry KW - FTIR KW - XRD KW - Raman KW - Chromatography KW - Papyrology PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428704 DO - https://doi.org/10.1038/srep46236 SN - 2045-2322 VL - 7 SP - 46236, 1 EP - 46236, 12 AN - OPUS4-42870 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Teixeira, M.M. A1 - Moreno, L.F. A1 - Stielow, B.J. A1 - Muszewska, A. A1 - Hainaut, M. A1 - Gonzaga, L. A1 - Abouelleil, A. A1 - Patan, J.S.L. A1 - Priest, M. A1 - Souza, R. A1 - Ferreira, K.S. A1 - Zeng, Q. A1 - da Cunha, M.M.L. A1 - Gladki, A. A1 - Barker, B. A1 - Vicente, V.A. A1 - de Souza, E.M. A1 - Almeida, S. A1 - Henrissat, B. A1 - Vasconelos, A.T.R. A1 - Deng, S. A1 - Vogelmayr, H. A1 - Moussa, T.A.A. A1 - Gorbushina, Anna A1 - Felipe, M.S.S. A1 - Cuomo, C.A. A1 - de Hoog, G.S. T1 - Exploring the genomic diversity of black yeasts and relatives (Chaetothyriales, Ascomycota) N2 - The order Chaetothyriales (Pezizomycotina, Ascomycetes) harbours obligatorily melanised fungi and includes numerous etiologic agents of chromoblastomycosis, phaeohyphomycosis and other diseases of vertebrate hosts. Diseases range from mild cutaneous to fatal cerebral or disseminated infections and affect humans and cold-blooded animals globally. In addition, Chaetothyriales comprise species with aquatic, rock-inhabiting, ant-associated, and mycoparasitic life-styles, as well as species that tolerate toxic compounds, suggesting a high degree of versatile extremotolerance. To understand their biology and divergent niche occupation, we sequenced and annotated a set of 23 genomes of main the human opportunists within the Chaetothyriales as well as related environmental species. Our analyses included fungi with diverse life-styles, namely opportunistic pathogens and closely related saprobes, to identify genomic adaptations related to pathogenesis. Furthermore, ecological preferences of Chaetothyriales were analysed, in conjuncture with the order-level phylogeny based on conserved ribosomal genes. General characteristics, phylogenomic relationships, transposable elements, sex-related genes, protein family evolution, genes related to protein degradation (MEROPS), carbohydrate-active enzymes (CAZymes), melanin synthesis and secondary metabolism were investigated and compared between species. Genome assemblies varied from 25.81 Mb (Capronia coronata) to 43.03 Mb (Cladophialophora immunda). The bantiana-clade contained the highest number of predicted genes (12 817 on average) as well as larger genomes. We found a low content of mobile elements, with DNA transposons from Tc1/Mariner superfamily being the most abundant across analysed species. Additionally, we identified a reduction of carbohydrate degrading enzymes, specifically many of the Glycosyl Hydrolase (GH) class, while most of the Pectin Lyase (PL) genes were lost in etiological agents of chromoblastomycosis and phaeohyphomycosis. An expansion was found in protein degrading peptidase enzyme families S12 (serine-type D-Ala-D-Ala carboxypeptidases) and M38 (isoaspartyl dipeptidases). Based on genomic information, a wide range of abilities of melanin biosynthesis was revealed; genes related to metabolically distinct DHN, DOPA and pyomelanin pathways were identified. The MAT (MAting Type) locus and other sexrelated genes were recognized in all 23 black fungi. Members of the asexual genera Fonsecaea and Cladophialophora appear to be heterothallic with a single copy of either MAT-1-1 or MAT-1-2 in each individual. All Capronia species are homothallic as both MAT1-1 and MAT1-2 genes were found in each single genome. The genomic synteny of the MAT-locus flanking genes (SLA2-APN2-COX13) is not conserved in black fungi as is commonly observed in Eurotiomycetes, indicating a unique genomic context for MAT in those species. The heterokaryon (het) genes expansion associated with the low selective pressure at the MAT-locus suggests that a parasexual cycle may play an important role in generating diversity among those fungi. KW - Black yeast KW - Comparative genomics KW - Chaetothyriales KW - Ecology KW - Evolution KW - Herpotrichiellaceae KW - Phylogeny PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-408720 DO - https://doi.org/10.1016/j.simyco.2017.01.001 SN - 1872-9797 VL - 86 IS - 1 SP - 1 EP - 28 PB - Elsevier CY - Amsterdam AN - OPUS4-40872 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hernández-Nava, E. A1 - Tammas-Williams, S. A1 - Smith, C. A1 - Léonard, Fabien A1 - Withers, P. J. A1 - Todd, I. A1 - Goodall, R. T1 - X-ray tomography characterisation of lattice structures processed by selective electron beam melting N2 - Metallic lattice structures intentionally contain open porosity; however, they can also contain unwanted closed porosity within the structural members. The entrained porosity and defects within three different geometries of Ti-6Al-4V lattices, fabricated by Selective Electron Beam Melting (SEBM), is assessed from X-ray computed tomography (CT) scans. The results suggest that horizontal struts that are built upon loose powder show particularly high (~20 x 10⁻³ vol %) levels of pores, as do nodes at which many (in our case 24) struts meet. On the other hand, for struts more closely aligned (0° to 54°) to the build direction, the fraction of porosity appears to be much lower (~0.17 x 10⁻³%) arising mainly from pores contained within the original atomised powder particles. KW - Cellular solids KW - Aqdditive manufacturing KW - Computed tomography KW - Titanium alloys PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413689 UR - http://www.mdpi.com/2075-4701/7/8/300 DO - https://doi.org/10.3390/met7080300 SN - 2075-4701 VL - 7 IS - 8 SP - Article 300, 1 EP - 12 PB - MDPI AN - OPUS4-41368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pavlovic, Mato A1 - Zoëga, Andreas A1 - Kurz, J. H. A1 - Zanotelli, Christina T1 - Investigations to introduce the probability of detection method for ultrasonic inspection of hollow axles at Deutsche Bahn N2 - The vast experience with the automated, ultrasonic system for the inspection of hollow railway axles used by Deutsche Bahn shows that much smaller flaws are detectable than required. This results in a number of false calls. False calls lead to unnecessary demounting and disassembling of wheelsets, which generates unnecessary additional costs. In order to adjust the sensitivity of the inspection system to reduce the number of false calls without compromising safety, the capability of the system to detect cracks needs to be comprehensively established. This capability can be quantified by using probability of detection (POD) curves for the system. The multi-parameter POD model makes it possible to include several factors that influence the crack detection in the analysis. The analysis presented in this paper shows that crack position, orientation, depth extension, and shape as well as the geometry of the axle all have influence on the ultrasonic response amplitude. For future work, calculation of the POD using multi-parameter POD model with these parameters is planned. T2 - ESIS TC24 Workshop "Integrity of Railway Structures" CY - Leoben, Austria DA - 24.10.2016 KW - Crack KW - Reliability KW - POD KW - Axle KW - Ultrasonic PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-415201 DO - https://doi.org/10.1016/j.prostr.2017.07.002 SN - 2452-3216 VL - 4 SP - 79 EP - 86 PB - Elsevier, B.V. AN - OPUS4-41520 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz T1 - Mitigation of railway induced vibration at the track, in the transmission path through the soil and at the building N2 - This contribution presents some principles and some examples of the mitigation of railway-induced ground vibrations. The principles are different for the mitigation measures at the track, in the soil or at the building. Force transfer functions of isolated and un-isolated track-soil systems, reflected and transmitted wave amplitudes at walls and trenches in the soil, and the transfer of the (free-field) vibration amplitudes to the foundation amplitudes of the building are analysed. The mitigation effect can be calculated by exact or simplified formulas. Some examples with 3D (finite-element boundary-element), 2D (beam-on-support), and 1D track models, 2D and 1D soil models, detailed 3D building models and finite or infinite 1D wall-floor models are investigated to find out if simple models can be used for a satisfactory prediction of the mitigation effect. The 1D track examples show that the force transfer of the track without vehicle can be exactly calculated, whereas the total force transfer can be calculated approximately if appropriate wheelset masses per track length are used for the isolated and the un-isolated track. The mitigation effect of a filled trench is calculated by a 2D finite element model and the results compare with simple transmission formula if the stiffness per area rather than the wave impedances are used for the infill material. The base isolation of a building is analysed by a detailed 3D model and the results are similar to the analytic results of a single wall with floors on the soil. Other reduction measures as different floor and column dimensions are usually less effective so that the clearly best mitigation solution at a building is a partly or a complete base isolation. T2 - X INTERNATIONAL CONFERENCE ON STRUCTURAL DYNAMICS (EURODYN 2017) KW - Mitigation KW - Soil-building interaction KW - Base isolation KW - Ground vibration PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420869 DO - https://doi.org/10.1016/j.proeng.2017.09.192 SN - 1877-7058 VL - 199 SP - 2312 EP - 2317 PB - Elsevier CY - London AN - OPUS4-42086 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz A1 - Said, Samir A1 - Müller, Roger T1 - Measurements on the vehicle-track interaction and the excitation of railway-induced ground vibration N2 - Two railway measurement campaigns have been performed in Germany and Switzerland which yield insight in the vehicle-track-soil interaction. The campaign in Germany has included simultaneous measurement of vehicle, track, and soil vibrations during train runs with 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. Two ballast tracks, one on the soil surface and one on a concrete bridge, have been investigated as well as a slab track in a tunnel. Ten different sites in Switzerland have been measured for soil properties and train-induced ground vibrations, which allow to determine the excitation forces of the railway traffic. New axle-box measurements at some of the Swiss sites have been analysed to get further experimental evidence. All these measurements have been evaluated to characterize the excitation processes. Relations between vehicle vibration and ground vibration can be observed. The vehicle vibrations, namely the accelerations of the wheelsets, yield the dynamic forces due to the passage over the irregularities of the vehicle and the track. The ground vibrations are correlated to these dynamic forces to a certain extent. Some mid-frequency ground vibration amplitudes, however, are higher than expected from the dynamic excitation forces. The experimental observations can be explained by an irregular response to the passage of the static loads, that means the passage of the static loads over an irregular ballast or soil. This correct understanding of the excitation processes is important for the prediction as well as for the mitigation of railway induced ground vibrations. T2 - X INTERNATIONAL CONFERENCE ON STRUCTURAL DYNAMICS (EURODYN 2017) KW - Vehicle-track interaction KW - Ground vibration KW - Track vibration KW - Railway measurement campaign KW - Axle box measurements PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-420889 DO - https://doi.org/10.1016/j.proeng.2017.09.390 SN - 1877-7058 VL - 199 SP - 2615 EP - 2620 PB - Elsevier CY - London AN - OPUS4-42088 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Maierhofer, Christiane A1 - Krankenhagen, Rainer A1 - Röllig, Mathias A1 - Hosseini, Seyed A1 - Heckel, Thomas A1 - Gaal, Mate A1 - Schadow, Florian A1 - Brackrock, Daniel A1 - Gower, M. A1 - Lodeiro, M. A1 - Baker, G. T1 - Quantitative Bewertung künstlicher und natürlicher Fehler in Faserverbundwerkstoffen mit aktiver Thermografie und Ultraschall N2 - Im EMRP-Projekt VITCEA werden komplementäre ZFP-Verfahren zur Prüfung von Faserverbundwerkstoffen weiterentwickelt und validiert. In diesem Beitrag werden Ergebnisse verschiedener Techniken der aktiven Thermografie und des Ultraschalls vorgestellt. Die Nachweisempfindlichkeiten bezüglich künstlicher und natürlicher Fehler mit unterschiedlichen lateralen Ausdehnungen und in verschiedenen Tiefen werden miteinander verglichen. T2 - DGZfP Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - CFK KW - GFK KW - Aktive Thermografie KW - Phased Array Ultraschall KW - Luftultraschall PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410902 SN - 978-3-940283-85-6 VL - BB 162 SP - Di1B1, 1 EP - Di1B1, 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung e. V. AN - OPUS4-41090 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Auersch, Lutz T1 - Simultaneous measurements of the vehicle, track, and soil vibrations at a surface, bridge, and tunnel railway line N2 - A complex measuring campaign has been performed including the simultaneous measurement of vehicle, track, and soil vibrations during train runs at 16, 25, 40, 63, 80, 100, 125, 140, 160 km/h, and impulse measurements of the passenger car, three track sections and the soil. A ballast track on the soil surface and on a concrete bridge have been investigated as well as a slab track in a tunnel. The evaluation and comparison of all these data shows a generally good agreement for all components if the strong low- and high-frequency cut-off characteristics of the layered and damped soil are incorporated. There is a strong causal correlation between the vehicle and the soil by the dynamic excitation forces and a weak relation between the track and the soil by the axle-sequence spectrum of the train. However, the similarity between the axle-impulse spectrum observed at the track and the spectra of the ground vibration lead to the special excitation component of “scattered axle impulses” which is pre-dominant at the far-field points of the soil. KW - Railway KW - Ground vibration KW - Vehicle-track interaction KW - Track-soil interaction KW - Measurements PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410224 DO - https://doi.org/10.1155/2017/1959286 VL - 2017 IS - ID 1959286 SP - 1 EP - 18 PB - Hindawi CY - Indien AN - OPUS4-41022 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dutto, Paola A1 - Stickle, M. M. A1 - Pastor, M. A1 - Manzanal, D. A1 - Yague, A. A1 - Tayyebi, S. A1 - Lin, C. A1 - Elizalde, M. D. ED - Cervera, Miguel T1 - Modelling of fluidised geomaterials: the case of the Aberfan and the Gypsum tailings impoundment flowslides N2 - The choice of a pure cohesive or a pure frictional viscoplastic model to represent the rheological behaviour of a flowslide is of paramount importance in order to obtain accurate results for real cases. The principal Goal of the present work is to clarify the influence of the type of viscous model—pure cohesive versus pure frictional—with the numerical reproduction of two different real flowslides that occurred in 1966: the Aberfan flowslide and the Gypsum tailings impoundment flowslide. In the present work, a depth-integrated model based on the v-pw Biot–Zienkiewicz formulation, enhanced with a diffusion-like equation to account for the pore pressure Evolution within the soil mass, is applied to both 1966 cases. For the Aberfan flowslide, a frictional viscous model based on Perzyna viscoplasticity is considered, while a pure cohesive viscous model (Bingham model) is considered for the case of the Gypsum flowslide. The numerical approach followed is the SPH method, which has been enriched by adding a 1D finite difference grid to each SPH node in order to improve the description of the pore water evolution in the propagating mixture. The results obtained by the performed simulations are in agreement with the documentation obtained through the UK National Archive (Aberfan flowslide) and the International Commission of large Dams (Gypsum flowslide). KW - Aberfan flowslide KW - SPH KW - Landslide propagation modelling KW - Perzyna viscoplasticity PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410493 DO - https://doi.org/10.3390/ma10050562 SN - 1996-1944 VL - 10 IS - 5 SP - 562, 1 EP - 562, 21 AN - OPUS4-41049 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Swaraj, S. A1 - Dietrich, Paul A1 - Unger, Wolfgang T1 - Simultaneous surface and bulk sensitive XAS measurements of magnetic particle clusters N2 - Magnetic iron oxide nanoparticle clusters (mnpc) coated with organic stabilizers were investigated using scanning transmission x-ray microscopy (STXM). Simultaneous surface and bulk sensitive Fe L₃ edge absorption spectra, obtained using a photomultiplier tube and a channeltron, were used to detect subtle changes in the oxidation state in the surface and bulk of Iron Oxide mnpc. The effectiveness of this mode of STXM operation is demonstrated for these nanoparticle clusters. T2 - X-Ray Microscopy Conference 2016 (XRM 2016) CY - Oxford, UK DA - 15.08. 2016 KW - Fe L3 edge absorption spectra KW - Scanning transmission x- ray microscopy KW - Magnetic iron oxide nanoparticle clusters KW - XAS PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410576 UR - http://iopscience.iop.org/article/10.1088/1742-6596/849/1/012014/pdf DO - https://doi.org/10.1088/1742-6596/849/1/012014 SN - 1742-6588 VL - 849 SP - 012014, 1 EP - 012014, 5 PB - IOP Publishing AN - OPUS4-41057 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mooshofer, H. A1 - Boehm, Rainer A1 - Heinrich, W. A1 - Fendt, K. A1 - Goldammer, M. A1 - Kolk, K. A1 - Vrana, J. T1 - Amplitudenbasierte Fehlergrößenbewertung mit SAFT: Auf dem Weg von der bildlichen Darstellung zum Messverfahren N2 - Die Größenbewertung von Anzeigen und die Bestimmung der Nachweisgrenze spielen bei der Ultraschallprüfung eine zentrale Rolle: Sie stellen sicher, dass kritische Ungänzen erfasst und bruchmechanisch behandelt werden können. Bei SAFT wurde bisher die Größe von Ungänzen dadurch bestimmt, dass die räumliche Anzeigenausdehnung im Rekonstruktionsergebnis ausgewertet wird, d.h. die Anzahl von Voxel über die sich eine Anzeige erstreckt. Auf diese Weise lassen sich jedoch nur Defektanzeigen bewerten, die größer oder gleich der Wellenlänge sind. Bei kleinen Defekten versagt diese Methode, d.h. es ist keine Größenbewertung möglich. Außerdem bietet diese Methode keine Aussage über die Nachweisgrenze des Verfahrens. Ein Hauptvorteil von SAFT gegenüber der konventionellen Ultraschallprüfung ist aber gerade die Verbesserung der Nachweisgrenze, denn SAFT steigert das Signal-Rausch-Verhältnis (SNR) gegenüber dem Gefügerauschen und reduziert statistisches Rauschen. Um diesen Hauptvorteil nutzen (und quantifizieren) zu können, wird für SAFT eine Methode zur Nachweisgrenzenbestimmung und zur Größenbewertung der Anzeigen kleiner Ungänzen benötigt. Neben ihrer räumlichen Ausdehnung lassen sich Anzeigen im SAFT-Ergebnis auch durch ihre Amplitude charakterisieren, wenn die Prüfkopfeigenschaften und die geometrischen Verhältnisse beim Scan berücksichtigt werden. Genauer gesagt durch die Amplitudensumme, in die - neben der Echoamplitude - auch die winkelabhängige Streucharakteristik eingeht. Im Folgenden wird dargelegt, dass sich die Amplitudensumme zur Nachweisgrenzenbestimmung und zur Größenbewertung kleiner Ungänzen eignet. Es wird der Zusammenhang zwischen der Amplitudensumme und der Größe von Ungänzen dargestellt, und es wird gezeigt, dass auch die Anzeigenposition und die Form des Prüfobjektes eine Rolle spielen können. Auf dieser Basis wird eine Methode zur Größenbestimmung kleiner Anzeigen im SAFT-Ergebnis entwickelt. Damit lässt sich das SAFT-Ergebnis als Ersatzfehlergröße darstellen, so wie das bei konventioneller Ultraschallprüfung z.B. mit Hilfe von AVG-Diagrammen erfolgt. Durch die Vervollständigung um die Größenbewertung ist SAFT nicht mehr nur ein bildgebendes Verfahren, sondern es kann vielmehr als vollwertiges Messverfahren dienen. T2 - DGZfP-Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Synthetic aperture focussing technique (SAFT) KW - Defektgrößenbewertung KW - Gewichtete Amplitudensumme KW - Kleine Reflektoren PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411571 SN - 978-3-940283-85-6 VL - 162 SP - 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-41157 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn T1 - Scattering on scattering N2 - Ultrafast experiments can reveal the spatiotemporal dynamics of nanostructure formation via scattering in background-free optical dark-field microscopy. KW - Ultrafast microscopy KW - Scattering KW - Darkfield microscopy KW - Laser ablation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411596 DO - https://doi.org/10.1038/lsa.2017.88 SN - 2047-7538 VL - 6 SP - e17088, 1 EP - 2 PB - Springer Nature AN - OPUS4-41159 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Cuéllar, Pablo A1 - Benseghier, Z. A1 - Luu, L.-H. A1 - Bonelli, S. A1 - Delenne, J.-Y. A1 - Radjai, F. A1 - Philippe, P. T1 - Numerical insight into the micromechanics of jet erosion of a cohesive granular material N2 - Here we investigate the physical mechanisms behind the surface erosion of a cohesive granular soil induced by an impinging jet by means of numerical simulations coupling fluid and grains at the microscale. The 2D numerical model combines the Discrete Element and Lattice Boltzmann methods (DEM-LBM) and accounts for the granular cohesion with a contact model featuring a paraboloidal yield surface. Here we review first the hydrodynamical conditions imposed by the fluid jet on a solid granular packing, turning then the attention to the impact of cohesion on the erosion kinetics. Finally, the use of an additional subcritical debonding damage model based on the work of Silvani and co-workers provides a novel insight into the internal solicitation of the cohesive granular sample by the impinging jet. T2 - 8th International Conference on Micromechanics on Granular Media CY - Montpellier, France DA - 03.07.2017 KW - Micromechanical modelling KW - LBM-DEM KW - Jet erosion KW - Granular cohesion KW - Subcritical debonding PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411186 DO - https://doi.org/10.1051/epjconf/201714015017 VL - 140 SP - Paper 15017, 1 EP - Paper 15017, 4 PB - The European Physical Journal (EPJ) - Web of Conferences AN - OPUS4-41118 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Philippe, P. A1 - Cuéllar, Pablo A1 - Brunier-Coulin, F. A1 - Luu, L.-H. A1 - Benahmed, N. A1 - Bonelli, S. A1 - Delenne, J.-Y. T1 - Physics of soil erosion at the microscale N2 - We focus here on the major and still relevant issue of soil erosion by fluid flows, and more specifically on the determination of both a critical threshold for erosion occurrence and a kinetics that specifies the rate of eroded matter entrainment. A state-of-the-art is first proposed with a critical view on the most commonly used methods and erosion models. It is then discussed an alternative strategy, promoting the use of model materials that allow systematic parametric investigations with the purpose of identifying more precisely the local mechanisms responsible for soil particle erosion and ultimately quantifying both critical onsets and kinetics, possibly through existing or novel empirical erosion laws. Finally, we present and discuss several examples following this methodology, implemented either by means of experiments or numerical simulations, and coupling erosion tests in several particular hydrodynamical configurations with wisely selected mechanical tests. T2 - 8th International Conference on Micromechanics on Granular Media CY - Montpellier, France DA - 03.07.2017 KW - Erosion phenomena KW - Onset of jet erosion KW - LBM-DEM numerical simulation KW - Experimental testing KW - PLIF-RIM optical techniques PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411198 DO - https://doi.org/10.1051/epjconf/201714008014 VL - 140 SP - Paper 08014, 1 EP - Paper 08014, 4 PB - The European Physical Journal (EPJ) - Web of Conferences AN - OPUS4-41119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Brunier-Coulin, F. A1 - Sarrat, J.-L. A1 - Cuéllar, Pablo A1 - Philippe, P. T1 - Experimental investigation of impinging jet erosion on model cohesive granular materials N2 - Erosion of soils affects both natural landscapes and engineering constructions as embankment dams or levees. Improving the safety of such earthen structures requires in particular finding out more about the elementary mechanisms involved in soil erosion. Towards this end, an experimental work was undertaken in three steps. First, several model materials were developed, made of grains (mostly glass beads) with solid bridges at particle contacts whose mechanical yield strength can be continuously varied. Furthermore, for most of them, we succeeded in obtaining a translucent system for the purpose of direct visualization. Second, these materials were tested against surface erosion by an impinging jet to determine a critical shear stress and a kinetic coefficient. Note that an adapted device based on optical techniques (combination of Refractive Index Matching and Planar Laser Induced Fluorescence) was used specifically for the transparent media. Third, some specifically developed mechanical tests, and particularly traction tests, were implemented to estimate the mechanical strength of the solid bridges both at micro-scale (single contact) and at macro-scale (sample) and to investigate a supposed relationship with soil resistance to erosion. T2 - 8th International Conference on Micromechanics on Granular Media CY - Montpellier, France DA - 03.07.2017 KW - Erosion onset KW - Experimental testing KW - Cohesive granular media KW - RIM-PLIF techniques PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-411215 DO - https://doi.org/10.1051/epjconf/201714008002 VL - 140 SP - Paper 08002, 1 EP - Paper 08002, 4 PB - The European Physical Journal (EPJ) - Web of Conferences AN - OPUS4-41121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pfennig, Anja A1 - Kranzmann, Axel A1 - Wolthusen, Helmut T1 - Unusual Corrosion Behavior of 1.4542 Exposed a Laboratory Saline Aquifer Water CCS-Environment N2 - Differently heat treated coupons of 1.4542 were kept at T=60 °C and ambient pressure as well as p=100 bar for 700 h - 8000 h in an a) water saturated supercritical CO2 and b) CO2-saturated synthetic aquifer environment similar to on-shore CCS-sites in the Northern German Basin. Surface corrosion layers are homogeneous but unusually discontinuously ellipsoidal. After 8000 h at 100 bar maximum corrosion rate in the liquid phase is approximately 0.014 mm/year, with normalizing providing best corrosion resistance and approximately 0.003 mm/year in the supercritical phase where hardening+tempering at 670 °C leads to lowest corrosion rates. KW - CO2-storage KW - Supercritical CO2 KW - Steel KW - Pipeline KW - Corrosion KW - CCS PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418472 DO - https://doi.org/10.1016/j.egypro.2017.03.1679 VL - 114 SP - 5229 EP - 5240 PB - Elsevier Ltd. AN - OPUS4-41847 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pfennig, Anja A1 - Wolf, Marcus A1 - Gröber, Andre A1 - Böllinghaus, Thomas A1 - Kranzmann, Axel T1 - Corrosion fatigue of 1.4542 exposed to a laboratory saline aquifer water CCS-environment N2 - X5CrNiCuNb16-4 has been proven to be sufficient resistant in corrosive environments, but shows rather unusual corrosion behaviour in CCS environment. Therefore a series of 30 specimens was tested at stress amplitudes between 150 MPa and 500 MPa (sinusoidal dynamic test loads, R=-1; resonant frequency ∼ 30 Hz). Due to the rather heterogeneous fine machined surfaces (Rz=4) the specimens are comparable with prefabricated parts. X5CrNiCuNb16-4 reached the maximum number of cycles (10 x 106) at a stress amplitude of 150 MPa and lies 60% below the stress amplitude measured in air. The scatter range TN = 1:34 is disproportionately large. Although the fracture surface exhibited the typical striations and corroded surface areas no significant differences were found. The hardness was found to be homogeneous in all specimens tested at 335 HV10. Non-metallic inclusions were found within the microstructure, but no correlation could be found between the inclusions and early rupture. Still specimens that showed inclusions at the fracture surface and its cross section endured lower number of cycles. Additionally Aluminium was analysed in specimens with low number of cycles and may be cause for early rupture during corrosion fatigue tests. These findings reveal a very high sensitivity on a homogeneous microstructure upon the corrosion and corrosion fatigue behaviour of X5CrNiCuNb16-4 and needs to be taken into account when regarding this steel as pipe steel during injection of CO2 into saline aquifers. T2 - 13th International Conference on Greenhouse Gas Control Technologies CY - Lausanne, Switzerland DA - 14.11.2016 KW - Steel KW - Corrosion fatigue KW - Electrochemistry KW - Reliability KW - CCS KW - CO2-storage PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418525 DO - https://doi.org/10.1016/j.egypro.2017.03.1678 SN - 1876-6102 VL - 114 SP - 5219 EP - 5228 AN - OPUS4-41852 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Taabache, Soraya A1 - Bertin, Annabelle T1 - Vesicles from amphiphilic dumbbells and Janus dendrimers: bioinspired self-assembled structures for biomedical applications N2 - The current review focuses on vesicles obtained from the self-assembly of two types of dendritic macromolecules, namely amphiphilic Janus dendrimers (forming dendrimersomes) and amphiphilic dumbbells. In the first part, we will present some synthetic strategies and the various building blocks that can be used to obtain dendritic-based macromolecules, thereby showing their structural versatility. We put our focus on amphiphilic Janus dendrimers and amphiphilic dumbbells that form vesicles in water but we also encompass vesicles formed thereof in organic solvents. The second part of this review deals with the production methods of these vesicles at the nanoscale but also at the microscale. Furthermore, the influence of various parameters (intrinsic to the amphiphilic JD and extrinsic—from the environment) on the type of vesicle formed will be discussed. In the third part, we will review the numerous biomedical applications of these vesicles of nano- or micron-size. KW - Janus dendrimers KW - Amphiphilic dumbbells KW - Self-assembled structures KW - Dendrimersomes KW - Artificial cells PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418245 DO - https://doi.org/10.3390/polym9070280 SN - 2073-4360 VL - 9 IS - 7 SP - Article 280, 1 EP - 36 AN - OPUS4-41824 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Gaal, Mate A1 - Caldeira, Rui A1 - Bartusch, Jürgen A1 - Kupnik, M. T1 - Air-coupled ultrasonic ferroelectret receiver with additional DC voltage N2 - Highly sensitive air-coupled ultrasonic sensors are essential for various applications such as testing of composite materials. One of the major challenges for the development of air-coupled ultrasonic sensors is the impedance matching to air. With a lower acoustic impedance than the usual piezoelectric materials, charged cellular polypropylene film (cPP) offers better matching to air with a similar piezoelectric coefficient. The piezoelectric behaviour demonstrated by cPP comes from polarized air cells that create a permanent internal voltage. The sensitivity of the sensor varies with the application of an additional DC bias voltage. Thus, this work presents a cPP ultrasonic sensor with an improvement of up to 15 ± 1 dB on the signal-to-noise ratio. T2 - Eurosensors 2017 CY - Paris, France DA - 3.9.2017 KW - Ultrasonic KW - Air-coupled KW - Cellular polypropylene KW - Transducer KW - Ferroelectret PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419009 DO - https://doi.org/10.3390/proceedings1040362 VL - 1 IS - 4 SP - Article 362, 1 EP - 4 AN - OPUS4-41900 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Obaton, A-F. A1 - Fain, J. A1 - Djemaï, M. A1 - Meinel, Dietmar A1 - Léonard, Fabien A1 - Mahé, E. A1 - Lécuelle, B. A1 - Fouchet, J-J. A1 - Bruno, Giovanni T1 - In vivo XCT bone characterization of lattice structured implants fabricated by additive manufacturing N2 - Several cylindrical specimens and dental implants, presenting diagonal lattice structures with different cell sizes (600, 900 and 1200 µm) were additively manufactured by selective laser melting process. Then they were implanted for two months in a sheep. After removal, they were studied by Archimedes’ method as well as X-ray computed tomography in order to assess the penetration of bone into the lattice. We observed that the additive manufactured parts were geometrically conform to the theoretical specifications. However, several particles were left adhering to the surface of the lattice, thereby partly or entirely obstructing the cells. Nevertheless, bone penetration was clearly visible. We conclude that the 900 µm lattice cell size is more favourable to bone penetration than the 1200 µm lattice cell size, as the bone penetration is 84 % for 900 µm against 54 % for 1200 µm cell structures. The lower bone penetration value for the 1200 µm lattice cell could possibly be attributed to the short residence time in the sheep. Our results lead to the conclusion that lattice implants additively manufactured by selective laser melting enable better bone integration. KW - Biomedical engineering KW - Dentistry KW - Medical imaging KW - X-ray computer tomography PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418648 DO - https://doi.org/10.1016/j.heliyon.2017.e00374 SN - 2405-8440 IS - 3 SP - Article e00374, 1 EP - 21 PB - Elsevier Limited CY - 125 London Wall London, EC2Y 5AS United Kingdom AN - OPUS4-41864 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tahri, K. A1 - Tiebe, Carlo A1 - El Bari, N. A1 - Hübert, Thomas A1 - Bouchikhi, B. T1 - Geographical classification and adulteration detection of cumin by using electronic sensing coupled to multivariate analysis N2 - The objective of this work is to report the improvement obtained in the discrimination of complex aroma and taste with subtle differences in odor and flavor, by the use of fast suitable procedures for the cases of measurements in the field demanding decision-making in real time. The proposed electronic sensing systems, formed by an E-nose and VE-tongue, were used to discriminate cumin cultivars from different geographical origins, as well as to quantify the cumin adulteration percentages by using unsupervised and supervised chemometric tools. Thus, the results obtained are sufficiently encouraging as a starting point for the development of new electronic sensing systems with more improvement such the reliability of the sensors’ performance as well as the chemometric tools in order to deal with a complex dataset. KW - VE-tongue KW - E-nose KW - Chemometric tools KW - Cumin discrimination KW - Geographical origins KW - Adulteration detection PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-409735 DO - https://doi.org/10.1016/j.protcy.2017.04.102 SN - 2212-0173 VL - 27 SP - 240 EP - 241 PB - Elsevier B.V. AN - OPUS4-40973 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rudenko, A. A1 - Colombier, J.-P. A1 - Höhm, S. A1 - Rosenfeld, A. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Itina, T.E. T1 - Spontaneous periodic ordering on the surface and in the bulk of dielectrics irradiated by ultrafast laser: a shared electromagnetic origin N2 - Periodic self-organization of matter beyond the diffraction limit is a puzzling phenomenon, typical both for surface and bulk ultrashort laser processing. Here we compare the mechanisms of periodic nanostructure formation on the surface and in the bulk of fused silica. We show that volume nanogratings and surface nanoripples having subwavelength periodicity and oriented perpendicular to the laser polarization share the same electromagnetic origin. The nanostructure orientation is defined by the near-field local enhancement in the vicinity of the inhomogeneous scattering centers. The periodicity is attributed to the coherent superposition of the waves scattered at inhomogeneities. Numerical calculations also support the multipulse accumulation nature of nanogratings formation on the surface and inside fused silica. Laser surface processing by multiple laser pulses promotes the transition from the high spatial frequency perpendicularly oriented nanoripples to the low spatial frequency ripples, parallel or perpendicular to the laser polarization. The latter structures also share the electromagnetic origin, but are related to the incident field interference with the scattered far-field of rough non-metallic or transiently metallic surfaces. The characteristic ripple appearances are predicted by combined electromagnetic and thermo-mechanical approaches and supported by SEM images of the final surface morphology and by time-resolved pump-probe diffraction measurements. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser KW - Nanostructures KW - Dielectrics KW - Electromagnetic scattering PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-421747 UR - https://www.nature.com/articles/s41598-017-12502-4 DO - https://doi.org/10.1038/s41598-017-12502-4 SN - 2045-2322 VL - 7 SP - Article 12306, 1 EP - 14 PB - Springer Nature AN - OPUS4-42174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Kuroiwa, T. A1 - Zhu, Y. A1 - Inagaki, K. A1 - Long, S. A1 - Christopher, S. A1 - Puelles, M. A1 - Porinsky, M. A1 - Hatamleh, N. A1 - Murby, J. A1 - Merrick, J. A1 - White, I. A1 - Saxby, D. A1 - Caciano de Sena, R. A1 - Dominguez de Almeida, M. A1 - Vogl, Jochen A1 - Phukphatthanachai, Pranee A1 - Fung, W.-H. A1 - Yau, H.-P. A1 - Okumu, T. O. A1 - Kang'iri, J. N. A1 - Tellez, J. A. S. A1 - Campos, E. Z. A1 - Galvan, E. C. A1 - Kaewkhomdee, N. A1 - Taebunpakul, S. A1 - Thiengmanee, U. A1 - Yafa, C. A1 - Tokman, N. A1 - Tunc, M. A1 - Can, S. Z. T1 - Report of the CCQM-K123: trace elements in biodiesel fuel N2 - The CCQM-K123 key comparison was organized by the Inorganic Analysis Working Group (IAWG) of CCQM to assess and document the capabilities of the national metrology institutes (NMIs) or the designated institutes (DIs) to measure the mass fractions of sodium, calcium, potassium, magnesium phosphorous and sulfur in biodiesel fuel (BDF). The National Metrology Institute of Japan (NMIJ) and National Institute of Standards and Technology (NIST) acted as the coordinating laboratories. Results were submitted by 11 NMIs and DIs. The participants used different measurement methods, though most of them used inductively coupled plasma-mass spectrometry (ICP-MS), isotope dilution technique with ICP-MS and inductively coupled plasma-optical emission spectrometry (ICP-OES) with microwave acid digestion. The material was quite challenging and a number of questions were raised at the IAWG meeting. Concerning S, the variation in S results between participants, particularly those using IDMS methods was discussed at the IAWG meeting. BAM, NIST and NMIJ reviewed their experimental conditions, results and/or uncertainty calculations for IDMS. According to the additional evaluation and investigation, the variances between the revised results became smaller than the original one, the revised results were overlapping between IDMS measurements of S content at the k=2 level. It is not possible to calculate a KCRV with values being modified after submission. It was concluded that this KC does not support S measurements. Accounting for relative expanded uncertainty, comparability of measurement results for each of Na, Ca, K, Mg and P was successfully demonstrated by the participating NMIs or DIs. It is expected that sodium, calcium, potassium, magnesium and phosphorus at mass fractions greater than approximately 0.1 mg/kg, 0.1 mg/kg, 0.05 mg/kg, 0.05 mg/kg and 0.1 mg/kg respectively in biodiesel fuel and similar matrices (fuels and oils etc.) can be determined by each participant using the same technique(s) employed for this key comparison to achieve similar uncertainties mentioned in the present report. Furthermore, the results of this key comparison can be utilized along with the IAWG core capability approach. KW - Biodiesel KW - Fuel KW - Sulphur KW - Reference measurement PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393941 UR - http://iopscience.iop.org/article/10.1088/0026-1394/54/1A/08008/meta DO - https://doi.org/10.1088/0026-1394/54/1A/08008 SN - 0026-1394 SN - 1681-7575 VL - 54 SP - Tech. Suppl. 2017, 08008, 1 EP - 47 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-39394 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Kern, Simon A1 - Guhl, Svetlana A1 - Meyer, Klas A1 - Maiwald, Michael ED - Maiwald, Michael T1 - Validation report on NMR N2 - The departure from the current automation landscape to next generation automation concepts for the process industry has already begun. Smart functions of sensors simplify their use and enable plug and play integration, even though they may appear to be more complex at first sight. Smart sensors enable concepts like self-diagnostics, self-calibration, and self-configuration/ parameterization whenever our current automation landscape allows it. Here we summarize the currently discussed general requirements for process sensors 4.0 and introduce a smart online NMR sensor module as example, which was developed for an intensified industrial process funded by the EU’s Horizon 2020 research and innovation programme (www.consensspire.eu). KW - Process Monitoring KW - Online NMR Spectroscopy KW - Indirect Hard Modeling KW - Process Control KW - Process Analytical Technology KW - CONSENS PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435521 SP - 1 EP - 31 AN - OPUS4-43552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dackermann, U. A1 - Yu, Y. A1 - Niederleithinger, Ernst A1 - Li, J. A1 - Wiggenhauser, Herbert T1 - Condition Assessment of Foundation Piles and Utility Poles Based on Guided Wave Propagation Using a Network of Tactile Transducers and Support Vector Machines N2 - This paper presents a novel non-destructive testing and health monitoring system using a network of tactile transducers and accelerometers for the condition assessment and damage classification of foundation piles and utility poles. While in traditional pile integrity testing an impact hammer with broadband frequency excitation is typically used, the proposed testing system utilizes an innovative excitation system based on a network of tactile transducers to induce controlled narrow-band frequency stress waves. Thereby, the simultaneous excitation of multiple stress wave types and modes is avoided (or at least reduced), and targeted wave forms can be generated. The new testing system enables the testing and monitoring of foundation piles and utility poles where the top is inaccessible, making the new testing system suitable, for example, for the condition assessment of pile structures with obstructed heads and of poles with live wires. For system validation, the new system was experimentally tested on nine timber and concrete poles that were inflicted with several types of damage. The tactile transducers were excited with continuous sine wave signals of 1 kHz frequency. Support vector machines were employed together with advanced signal processing algorithms to distinguish recorded stress wave signals from pole structures with different types of damage. The results show that using fast Fourier transform signals, combined with principal component analysis as the input feature vector for support vector machine (SVM) classifiers with different kernel functions, can achieve damage classification with accuracies of 92.5% ± 7.5%. KW - Structural Health Monitoring KW - Non-Destructive Testing KW - Sensor network KW - Support vector machine KW - Utility poles PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-434868 UR - http://www.mdpi.com/1424-8220/17/12/2938 DO - https://doi.org/10.3390/s17122938 SN - 1424-8220 VL - 17 IS - 12 SP - Article 2938, 1 EP - 16 PB - MDPI CY - Basel, Schweiz AN - OPUS4-43486 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Mair, Georg A1 - Becker, Ben A1 - Duffner, Eric A1 - John, Sebastian T1 - Storage systems for CGH2- systematic improvement of RC&s composite storage systems for compressed hydrogen - systematic improvement of regulations for more attractive storage units N2 - Hydrogen is an attractive energy carrier that requires high effort for safe storage. For ensuring safety they have to undergo a challenging approval process. Relevant standards and regulations for composite cylinders used for the transport of for on-board storage of hydrogen are currently based on deterministic (e.g. ISO 11119-3) or semi-probabilistic (UN GTR No. 13) criteria. This paper analysis the properties of such methods in regards to the evaluation of load cycle strength. Their characteristics are compared with the probabilistic approach of the BAM. Based on Monte-Carlo simulations, the available design range (mean value and scatter of strength criteria) of current concepts were exemplarily estimated. The aspect of small sample sizes is analysed and discussed with respect to the evaluation procedures. T2 - 10th International Conference on Sustainable Energy and Environmental Protection CY - Bled, Slovenia DA - 27.06.2017 KW - Probabilistic KW - Hydrogen KW - Composite KW - Cylinder KW - Regulations KW - Load cycles KW - GTR 13 KW - ISO 11119 PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-416820 SN - 978-961-286-054-7 DO - https://doi.org/10.18690/978-961-286-054-7 SP - 1 EP - 10 PB - University of Maribor Press CY - Maribor, Slovenia AN - OPUS4-41682 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hirthammer, Volker A1 - Unger, Jörg F. A1 - Ozbolt, J. ED - von Scheven, M. ED - Keip, M.-A. ED - Karajan, N. T1 - Mesoscale influence on the macroscopic material behavior of concrete N2 - The heterogeneous mesostructure of concreted causes local stress concentrations. Stress dependent phenomena like damage and creep as well as their interactions are effected by those stress concentrations. Therefore a material model’s macroscopic behavior will differ whether the mesoscale structure is considered or not. The differences between the mesoscale approach and an homogeneous approach will be presented. The results are discussed with focus on the true materials behavior. T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry CY - Stuttgart, Germany DA - 11.10.2017 KW - Mesoscale KW - Material behavior KW - Macroscopic PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436611 DO - https://doi.org/10.18419/opus-9334 VL - 7 SP - MS13, 414 EP - 417 PB - Institute for Structural Mechanics, University of Stuttgart CY - Stuttgart AN - OPUS4-43661 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pohl, Christoph A1 - Unger, Jörg F. ED - von Scheven, M. ED - Keip, M.-A. ED - Karajan, N. T1 - Obtaining macroscopic properties from a mesoscale thermomechanical model of concrete N2 - A coupled thermomechanical mesoscale model for concrete under heating is presented. When considering the heterogeneous structure under coupled loads, complex macroscopic material properties can be modelled using simple constitutive relations. For instance, damage evolution is directly driven by the incompatibility of thermal strains between matrix and aggregates. Without prescribing fc = f(T), a decline in compressive strength with rising temperatures will be shown. T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry CY - Stuttgart, Germany DA - 11.10.2017 KW - Multiscale KW - Concrete mesoscale KW - Thermomechanical PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436540 DO - https://doi.org/10.18419/opus-9334 VL - 7 SP - MS13, 418 EP - 422 PB - Institute for Structural Mechanics, University of Stuttgart CY - Stuttgart AN - OPUS4-43654 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Huschke, Philip A1 - Unger, Jörg F. ED - von Scheven, M. ED - Keip, M.-A. ED - Karajan, N. T1 - Domain decomposition methods for fracture mechanics problems and its application to fiber reinforced concrete N2 - A finite element tearing and interconnecting (FETI) approach for phase-field models and Gradient enhanced damage models is presented. These diffusive crack models can solve fracture mechanics problems by integrating a set of partial differential equations and thus avoid the explicit treatment of discontinuities. However, they require a fine discretization in the vicinity of the crack. FETI methods distribute the computational cost among multiple processors and thus speed up the computation. T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry CY - Stuttgart, Germany DA - 11.10.2017 KW - FETI KW - Domain decomposition methods KW - Fracture mechanics problems PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436764 DO - https://doi.org/10.18419/opus-9334 VL - 7 SP - 444 EP - 448 PB - Institute for Structural Mechanics, University of Stuttgart CY - Stuttgart AN - OPUS4-43676 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Casperson, Ralf A1 - Munzke, Dorit A1 - Pohl, Rainer T1 - Wirbelstromprüfung an Composite-Druckgefäßen N2 - Composite-Druckgefäße für den Gefahrguttransport sowie für Wasserstoff- und Erdgasfahrzeuge bestehen aus einem lasttragenden Composite und einer gasdichten, metallischen oder polymeren Barriereschicht (Liner). Zur Untersuchung des Alterungsverhaltens solcher Composite-Druckgefäße wird in der BAM das interdisziplinäre Themenfeldprojekt COD-AGE durchgeführt. Ziel des Projektes ist die Entwicklung von Methoden und Modellen zur Beschreibung und Bestimmung des Alterungsverhaltens von Carbonfaser-Compositen (CFK) am Beispiel von Druckgefäßen, um eine bessere Vorhersage der Alterung und der sicheren Gebrauchsdauer zu ermöglichen. Ein Schwerpunkt in diesem Projekt ist die Bereitstellung geeigneter ZfP-Methoden. Dabei geht es sowohl um versuchsbegleitende Prüfungen, als auch um die mögliche Entwicklung von Prüfeinrichtungen für den späteren praktischen Gebrauch. In diesem Vortrag werden Prüfsysteme und Prüfergebnisse der „konventionellen“ Wirbelstromprüfung vorgestellt. In einem ersten Schritt wurden Versuche an bereits geschädigten Druckgefäßen durchgeführt. Dabei wurden Druckgefäße mit den Materialpaarungen Stahl-CFK, Aluminium-CFK und Kunststoff-CFK untersucht. Die Dicken der CFK-Schichten reichten hierbei von ca. 4 mm bis ca. 8 mm. Anfangs wurden die Gefäße mit verschiedenen Sensoren von außen geprüft. Es konnten sowohl Beschädigungen des metallischen Liners, als auch Strukturen des CFK-Geflechts nachgewiesen werden. In einem zweiten Schritt wurden die Gefäße von innen geprüft. Hierbei bestand die besondere Herausforderung in der Prüfung eines Zylinders von 150 mm Durchmesser durch einen Zugang von nur 15 mm Durchmesser. Mit den bei diesen Vorversuchen optimierten Prüfsystemen wurden dann begleitende Prüfungen bei Alterungsversuchen durchgeführt. In den Alterungsversuchen wurden Druckbehälter mit einem ca. 4 mm dicken Aluminiumliner und ca. 3,5 mm dicker CFK-Ummantelung untersucht. Typisches Einsatzgebiet solcher Flaschen sind Atemschutzgeräte bei der Feuerwehr. Die verschiedenen Prüfsysteme und die mit ihnen erzielten Ergebnisse werden vorgestellt. T2 - DGZfP-Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Composite-Druckgefäß KW - Wirbelstromprüfung KW - CFK PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403577 SN - 978-3-940283-85-6 VL - 162 SP - 1 EP - 9 PB - DGZfP e.V. AN - OPUS4-40357 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Pohl, Rainer A1 - Casperson, Ralf A1 - Maierhofer, Christiane A1 - Müller, Jan A1 - Pelkner, Matthias T1 - Gegenüberstellung von Wirbelstromprüfung und aktiver Thermografie an CFK-Versuchskörpern N2 - In vielen Bereichen der Technik haben Konstruktionen unter Einsatz von CFK-Bauteilen und Komponenten die klassischen Metalle abgelöst. Die zerstörungsfreie Prüfung solcher CFK-Bauteile gewinnt somit zunehmend an Bedeutung. Ein mögliches Prüfverfahren ist dabei die Wirbelstromprüfung. Aufgrund der relativ geringen elektrischen Leitfähigkeit von CFK-Komponenten kommt hierbei häufig die sogenannte HF-Wirbelstromprüfung zum Einsatz. In verschiedenen Untersuchungen der BAM konnten jedoch auch mit Wirbelstromprüfsystemen in niedrigen Frequenzbereichen gute Ergebnisse erzielt werden. Um die Möglichkeiten und Grenzen dieser konventionellen Wirbelstromprüfung auszuloten, wurden Messungen an Versuchskörpern durchgeführt, welche bereits bei der Validierung der Blitz- und Lock-in-Thermografie für neue Verfahrensnormen erfolgreich eingesetzt wurden. Ein Typ dieser Versuchskörper sind Flachproben aus CFK von 6 mm Dicke. In diesen wurden Flachbodenbohrungen mit Durchmessern zwischen 4 mm und 24 mm eingebracht. Die Restwandstärken liegen zwischen 0,06 mm und 3,66 mm. Ein weiterer CFK-Versuchskörper hat die Geometrie eines Stufenkeiles. Bei verschiedenen Stufenkeilen sind Wanddicken zwischen 1,4 mm und 5,4 mm realisiert worden. In diesen wurden künstliche quadratische Delaminationen mit Kantenlängen zwischen 2 mm und 20 mm eingebracht. Die Ergebnisse der Wirbelstromprüfung werden denen der aktiven Thermografie gegenübergestellt. Zur Nachbildung von Kompositwerkstoffen wurden die flachen Versuchskörper mit geeigneten Versuchskörpern aus Aluminium und Stahl kombiniert. Die Wirbelstromprüfungen wurden mit einem handelsüblichen Prüfgerät im Frequenzbereich zwischen 500 Hz und 3 MHz und entsprechend angepassten Sensoren durchgeführt. T2 - DGZfP Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Wirbelstromprüfung KW - Aktive Thermografie KW - CFK PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403607 SN - 978-3-940283-85-6 VL - 162 SP - 1 EP - 10 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin AN - OPUS4-40360 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Simon, Franz-Georg A1 - Holm, Olaf T1 - Exergetische Bewertung von Rohstoffen am Beispiel von Kupfer T1 - Exergetic assessment of raw materials using the example of copper N2 - Für die Herstellung von Kupfer aus Primär- und Sekundärressourcen wurde eine Exergieanalyse der Aufbereitungs- und Gewinnungsverfahren durchgeführt. Für die Stoffgemische Kupfererz, Kupferkonzentrat und Hausmüllverbrennungsasche wurden die Exergien tabellarisch berechnet. Die Exergieaufwände der technischen Prozesse zur Kupferherstellung wurden mit den thermodynamisch minimal notwendigen Aufwänden verglichen. Die Nutzung von Sekundärrohstoffen aus Abfällen ist über weite Bereiche vorteilhaft, insb. wenn das Kupfer bereits in der metallischen Form vorliegt. KW - Exergie KW - Hausmüllverbrennungsasche KW - Hydrometallurgie KW - Pyrometallurgie KW - Kumulierter Exergieaufwand PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390496 UR - http://onlinelibrary.wiley.com/doi/10.1002/cite.201600089/epdf DO - https://doi.org/10.1002/cite.201600089 SN - 1522-2640 SN - 0009-286X VL - 89 IS - 1-2, SI SP - 108 EP - 116 PB - Wiley VCH Verlag CY - Weinheim AN - OPUS4-39049 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Häusler, Ines A1 - Schwarze, C. A1 - Umer Bilal, M. A1 - Valencia Ramirez, D. A1 - Hetaba, W. A1 - Darvishi Kamachali, Reza A1 - Skrotzki, Birgit T1 - Precipitation of T1 and theta′ Phase in Al‐4Cu‐1Li‐0.25Mn During Age Hardening: Microstructural Investigation and Phase‐Field Simulation N2 - Experimental and phase field studies of age hardening response of a high purity Al‐4Cu‐1Li‐0.25Mn‐alloy (mass %) during isothermal aging are conducted. In the experiments, two hardening phases are identified: the tetragonal θ′ (Al₂Cu) phase and the hexagonal T1 (Al₂CuLi) phase. Both are plate shaped and of nm size. They are analyzed with respect to the development of their size, number density and volume fraction during aging by applying different analysis techniques in TEM in combination with quantitative microstructural analysis. 3D phase‐field simulations of formation and growth of θ′ phase are performed in which the full interfacial, chemical and elastic energy contributions are taken into account. 2D simulations of T1 phase are also investigated using multi‐component diffusion without elasticity. This is a first step toward a complex phase‐field study of T1 phase in the ternary alloy. The comparison between experimental and simulated data shows similar trends. The still unsaturated volume fraction indicates that the precipitates are in the growth stage and that the coarsening/ripening stage has not yet been reached. KW - Al‐Cu‐Li‐alloy KW - Precipitates KW - Age hardening KW - Volume fraction KW - Number density KW - Microstructure KW - Phase‐field modeling KW - Elasticity KW - Multi‐component diffusion KW - Growth kinetics PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390473 DO - https://doi.org/10.3390/ma10020117 SN - 1996-1944 VL - 10 IS - 2 SP - Article 117, 1 EP - 21 PB - MDPI CY - Basel, Schweiz AN - OPUS4-39047 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Titscher, Thomas A1 - Unger, Jörg F. A1 - Oliver, J. ED - von Scheven, M. ED - Keip, M.-A. ED - Karajan, N. T1 - Cycle-by-cycle fatigue damage model for concrete N2 - Damage caused by stress concentrations in the complex mesoscopic geometry of concrete leads to continuous stress redistribution over the material’s life time. The presented fatigue damage model captures this by resolving each load cycle in a cycle-by-cycle time integration. The model extends a static damage model to failure caused by the (time dependent) strain amplitudes and, thus, allows calibrating the majority of the material’s parameters in static experiments. T2 - 7th GACM Colloquium on Computational Mechanics for Young Scientists from Academia and Industry CY - Stuttgart, Germany DA - 11.10.2017 KW - Cycle-by-cycle KW - Fatigue damage KW - Mesoscopic PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-436681 DO - https://doi.org/10.18419/opus-9334 VL - 7 SP - MS13, 440 EP - 443 PB - Institute for Structural Mechanics, University of Stuttgart CY - Stuttgart AN - OPUS4-43668 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bender, P A1 - Balceris, C. A1 - Ludwig, F A1 - Posth, O A1 - Bogart, L. K. A1 - Szczerba, Wojciech A1 - Castro, A A1 - Nilsson, L A1 - Costo, R A1 - Gavilan, H A1 - Gonzalez-Alonso, D A1 - de Pedro, I A1 - Barquin, L. F. A1 - Johansson, C T1 - Distribution functions of magnetic nanoparticles determined by a numerical inversion method N2 - In the present study, we applied a regularized inversion method to extract the particle size, magnetic moment and relaxation-time distribution of magnetic nanoparticles from small-angle x-ray scattering (SAXS), DC magnetization (DCM) and AC susceptibility (ACS) measurements. For the measurements the particles were colloidally dispersed in water. At first approximation the particles could be assumed to be spherically shaped and homogeneously magnetized single-domain particles. As model functions for the inversion, we used the particle form factor of a sphere (SAXS), the Langevin function (DCM) and the Debye model (ACS). The extracted distributions exhibited features/peaks that could be distinctly attributed to the individually dispersed and non-interacting nanoparticles. Further analysis of these peaks enabled, in combination with a prior characterization of the particle ensemble by electron microscopy and dynamic light scattering, a detailed structural and magnetic characterization of the particles. Additionally, all three extracted distributions featured peaks, which indicated deviations of the scattering (SAXS), magnetization (DCM) or relaxation (ACS) behavior from the one expected for individually dispersed, homogeneously magnetized nanoparticles. These deviations could be mainly attributed to partial agglomeration (SAXS, DCM, ACS), uncorrelated surface spins (DCM) and/or intra-well relaxation processes (ACS). The main advantage of the numerical inversion method is that no ad hoc assumptions regarding the line shape of the extracted distribution functions are required, which enabled the detection of these contributions. We highlighted this by comparing the results with the results obtained by standard model fits, where the functional form of the distributions was a priori assumed to be log-normal shaped. KW - SAXS KW - Small-angle X-ray scattering KW - Nanoparticle PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429373 DO - https://doi.org/10.1088/1367-2630/aa73b4 SN - 1367-2630 VL - 19 SP - 073012, 1 EP - 073012, 19 PB - IOP Publ. Ltd. AN - OPUS4-42937 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauw, Brian Richard A1 - Smith, A. J. A1 - Snow, T. A1 - Terril, N. J. A1 - Thünemann, Andreas T1 - The modular small-angle X-ray scattering data correction sequence N2 - Data correction is probably the least favourite activity amongst users experimenting with small-angle X-ray scattering: if it is not done sufficiently well, this may become evident only during the data analysis stage, necessitating the repetition of the data corrections from scratch. A recommended comprehensive sequence of elementary data correction steps is presented here to alleviate the difficulties associated with data correction, both in the laboratory and at the synchrotron. When applied in the proposed order to the raw signals, the resulting absolute scattering cross section will provide a high degree of accuracy for a very wide range of samples, with its values accompanied by uncertainty estimates. The method can be applied without modification to any pinhole-collimated instruments with photon-counting direct-detection area detectors. KW - Small-angle X-ray scattering KW - SAXS KW - Accuracy KW - Methodology KW - Data correction PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-432114 DO - https://doi.org/10.1107/S1600576717015096 SN - 1600-5767 VL - 50 IS - 6 SP - 1800 EP - 1811 PB - International Union of Crystallography AN - OPUS4-43211 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Pauw, Brian Richard A1 - Kästner, Claudia A1 - Thünemann, Andreas T1 - Nanoparticle size distribution quantification: results of a small-angle X-ray scattering inter-laboratory comparison N2 - This paper presents the first worldwide inter-laboratory comparison of small-angle X-ray scattering (SAXS) for nanoparticle sizing. The measurands in this comparison are the mean particle radius, the width of the size distribution and the particle concentration. The investigated sample consists of dispersed silver nanoparticles, surrounded by a stabilizing polymeric shell of poly(acrylic acid). The silver cores dominate the X-ray scattering pattern, leading to the determination of their radius size distribution using (i) the generalized indirect Fourier transformation method, (ii) classical model fitting using SASfit and (iii) a Monte Carlo fitting approach using McSAS. The application of these three methods to the collected data sets from the various laboratories produces consistent mean number- and volume-weighted core radii of Rn = 2.76 (6) nm and Rv = 3.20 (4) nm, respectively. The corresponding widths of the lognormal radius distribution of the particles were σn = 0.65 (1) nm and σv = 0.71 (1) nm. The particle concentration determined using this method was 3.0 (4) g l−1 or 4.2 (7) × 10−6 mol l−1. These results are affected slightly by the choice of data evaluation procedure, but not by the instruments: the participating laboratories at synchrotron SAXS beamlines, commercial and in-house-designed instruments were all able to provide highly consistent data. This demonstrates that SAXS is a suitable method for revealing particle size distributions in the sub-20 nm region (at minimum), out of reach for most other analytical methods. KW - SAXS KW - Small-angle X-ray scattering KW - Silver nanoparticles PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-422800 DO - https://doi.org/10.1107/S160057671701010X SN - 1600-5767 VL - 50 IS - 5 SP - 1280 EP - 1288 PB - (IUCr) International Union of Crystallography AN - OPUS4-42280 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -