TY - JOUR A1 - Liehr, Sascha A1 - Muanenda, Y. S. A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Relative change measurement of physical quantities using dual-wavelength coherent OTDR N2 - We propose the use of alternating pulse wavelengths in a direct-detection coherent optical time domain reflectometry (C-OTDR) setup not only to measure strain and temperature changes but also to determine the correct algebraic sign of the change. The sign information is essential for the intended use in distributed mode shape analysis of civil engineering structures. Correlating relative backscatter signal shifts in the temporal/signal domain allows for measuring with correct magnitude and sign. This novel approach is simulated, experimentally implemented and demonstrated for temperature change measurement at a spatial resolution of 1 m. KW - Fiber optics sensors KW - Backscattering KW - Rayleigh KW - C-OTDR KW - Distributed sensing KW - Temperature measurement KW - Strain measurement PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389449 DO - https://doi.org/10.1364/OE.25.000720 SN - 1094-4087 VL - 25 IS - 2 SP - 720 EP - 729 PB - Optical Society of America CY - Washington, DC, USA AN - OPUS4-38944 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Dieck, S. A1 - Rosemann, Paul A1 - Kromm, Arne A1 - Halle, T. T1 - Reversed austenite for enhancing ductility of martensitic stainless steel N2 - The novel heat treatment concept, “quenching and partitioning” (Q&P) has been developed for high strength steels with enhanced formability. This heat treatment involves quenching of austenite to a temperature between martensite start and finish, to receive a several amount of retained austenite. During the subsequent annealing treatment, the so called partitioning, the retained austenite is stabilized due to carbon diffusion, which results in enhanced formability and strength regarding strain induced austenite to martensite transformation. In this study a Q&P heat treatment was applied to a Fe-0.45C-0.65Mn-0.34Si-13.95Cr stainless martensite. Thereby the initial quench end temperature and the partitioning time were varied to characterize their influence on microstructural evolution. The microstructural changes were analysed by dilatometer measurements, X-ray diffraction and scanning electron microscopy, including electron backscatter diffraction. Compression testing was made to examine the mechanical behaviour. It was found that an increasing partitioning time up to 30 min leads to an enhanced formability without loss in strength due to a higher amount of stabilized retained and reversed austenite as well as precipitation hardening. T2 - 19th Chemnitz Seminar on Materials Engineering – 19. Werkstofftechnisches Kolloquium CY - Chemnitz, Germany DA - 16.03.2017 KW - Quenching and partitioning KW - Martensitic stainless steels KW - Heat treatment KW - Transformation induced plasticity KW - High ductility PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395328 DO - https://doi.org/10.1088/1757-899X/181/1/012034 SN - 1757-899X SN - 1757-8981 VL - 181 IS - Conference 1 SP - Article UNSP 012034, 1 EP - 8 PB - IOP Publishing CY - Bristol, UK AN - OPUS4-39532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Müller, Jan P. A1 - Götschel, S. A1 - Weiser, M. A1 - Maierhofer, Christiane T1 - Thermografie mit optimierter Anregung für die quantitative Untersuchung von Delaminationen in kohlenstofffaserverstärkten Kunststoffen N2 - Da kohlenstofffaserverstärkte Kunststoffe (CFK) in anspruchsvollen sicherheitsrelevanten Einsatzgebieten wie im Automobilbau und in der Luftfahrt eingesetzt werden, besteht ein zunehmender Bedarf an zerstörungsfreien Prüfmethoden. Ziel ist die Gewährleistung der Sicherheit und Zuverlässigkeit der eingesetzten Bauteile. Aktive Thermografieverfahren ermöglichen die effiziente Prüfung großer Flächen mit hoher Auflösung in wenigen Arbeitsschritten. Ein wichtiges Teilgebiet der Prüfungen ist die Ortung und Charakterisierung von Delaminationen, die sowohl bereits in der Fertigung als auch während der Nutzung eines Bauteils auftreten können, und dessen strukturelle Integrität schwächen. In diesem Beitrag werden CFK-Strukturen mit künstlichen und natürlichen Delaminationen mit Hilfe unterschiedlich zeitlich modulierter Strahlungsquellen experimentell untersucht. Verwendet werden dabei Anregungen mit Blitzlampen und mit frequenzmodulierten Halogenlampen. Mittels Filterfunktionen im Zeit- und Frequenzbereich wird das Kontrast-zu-Rausch-Verhältnis (CNR) der detektierten Fehlstellen optimiert. Verglichen werden anschließend die Nachweisempfindlichkeit, das CNR und die Ortsauflösung der zu charakterisierenden Delaminationen für die unterschiedlichen Anregungs- und Auswertungstechniken. Ergänzt werden die Experimente durch numerische Simulationen des dreidimensionalen Wärmetransportes. T2 - DGZfP Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - CFK KW - Contrast Noise Ratio KW - Lock-in Thermografie KW - Gepulste Thermografie KW - Kurzzeit-Fouriertransformation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404276 SN - 978-3-940283-85-6 VL - DGZfP BB 162 SP - Mi.1.A.4, 1 EP - 11 AN - OPUS4-40427 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kotschate, Daniel A1 - Gohlke, Dirk A1 - Meinig, Silvia A1 - Kaszemeikat, T. T1 - Hochauflösende Reinheitsgradbestimmung - Fertigung von Referenzfehlern N2 - Regelwerke zur zerstörungsfreien Bestimmung des Reinheitsgrades wie das SEP 1927 und die ASTM E588 erreichen ihre Vergleichbarkeit unter Anwendung von - vergleichsweise einfachen - Referenzfehlern. Hinsichtlich Realisierbarkeit wird somit der Kompromiss zwischen Herstellung des Referenzfehlers und der erreichbaren Nachweisgrenze gefunden. Zur Weiterentwicklung über die Grenzen der SEP1927 hinaus, wurde der Versuch unternommen Fehler kleiner 500 μm herzustellen - welche aufgrund der geringen geometrischen Ausdehnung fertigungsbedingt schwierig zu realisieren sind. Bei den vergleichenden Untersuchungen kristallisierten sich zwei Fertigungsverfahren, Funkenerosion (EDM: electrical discharge maching) und die Fertigung der Bohrungen unter Verwendung eines Hochleistungslasers, als vielversprechend heraus. Zunächst wurden die Fehler mit beiden Verfahren in unterschiedlichen Größen (100, 250 und 100 μm) und Tiefen (1, 1,5 und 2 mm) unter Anwendung von computertomographischen Verfahren der Röntgenprüfung, die Geometrie der eingebrachten Fehlstellen und anschließend durch hochauflösende Tauchtechnikmessungen das Reflektionsverhalten charakterisiert. T2 - DGZfP Jahrestagung CY - Koblenz, Germany DA - 22.05.2017 KW - Materialcharakterisierung KW - Reinheitsgradbestimmung KW - Ultraschalltauchtechnik PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403505 SN - 978-3-940283-85-6 SP - P20, 1 EP - 2 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-40350 LA - deu 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 - 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 - Kindzierski, V. A1 - Raschke, Silvia A1 - Knabe, Nicole A1 - Siedler, F. A1 - Scheffer, B. A1 - Pflüger-Grau, K. A1 - Pfeiffer, F. A1 - Oesterhelt, D. A1 - Marin-Sanguino, A. A1 - Kunte, Hans-Jörg T1 - Osmoregulation in the halophilic bacterium halomonas elongata: A case study for integrative systems biology N2 - Halophilic bacteria use a variety of osmoregulatory methods, such as the accumulation of one or more compatible solutes. The wide diversity of compounds that can act as compatible solute complicates the task of understanding the different strategies that halophilic bacteria use to cope with salt. This is specially challenging when attempting to go beyond the pathway that produces a certain compatible solute towards an understanding of how the metabolic network as a whole addresses the problem. Metabolic reconstruction based on genomic data together with Flux Balance Analysis (FBA) is a promising tool to gain insight into this problem. However, as more of these reconstructions become available, it becomes clear that processes predicted by genome annotation may not reflect the processes that are active in vivo. As a case in point, E. coli is unable to grow aerobically on citrate in spite of having all the necessary genes to do it. It has also been shown that the realization of this genetic potential into an actual capability to metabolize citrate is an extremely unlikely event under normal evolutionary conditions. Moreover, many marine bacteria seem to have the same pathways to metabolize glucose but each species uses a different one. In this work, a metabolic network inferred from genomic annotation of the halophilic bacterium Halomonas elongata and proteomic profiling experiments are used as a starting point to motivate targeted experiments in order to find out some of the defining features of the osmoregulatory strategies of this bacterium. This new information is then used to refine the network in order to describe the actual capabilities of H. elongata, rather than its genetic potential. KW - Halomonas elongata KW - Systems biology KW - Flux balance analysis KW - Proteomic analysis PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391172 DO - https://doi.org/10.1371/journal.pone.0168818 SN - 1932-6203 VL - 12 IS - 1 SP - Article e0168818, 1 EP - 22 AN - OPUS4-39117 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Dietrich, P. A1 - Thissen, A. A1 - Kulak, N. A1 - Kjaervik, Marit A1 - Unger, Wolfgang T1 - XPS surface chemical analysis of aqueous solutions with EnviroESCA N2 - Water and aqueous reagents are essential in any biological process or system. But apart from a few special low vapor-pressure cases, liquids have not been accessible to any technique requiring UHV conditions. EnviroESCA opens up this exciting field of applications. In this paper first results from water based samples are presented as a proof of concept to demonstrate the special capabilities of EnviroESCA analyzing liquid samples. The following solutions were investigated under near ambient pressure conditions: i.) water, ii.) brine, iii.) an oil in water dispersion, iv.) aqueous iron(II) sulfate heptahydrate, and v.) a suspension of nano silver particles in water. KW - Surface Analysis KW - Near Ambient Pressure XPS KW - Aqueous Solutions PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-394603 UR - http://www.enviro.specs.de/cms/upload/bilder/EnviroESCA/Applications/Liquids/Application-Note_EnviroESCA_Aqueous_Solutions.pdf N1 - BAM Mitarbeiter Beitrag im Acknowledgement definiert. IS - #000394 SP - 1 PB - SPECS CY - Berlin AN - OPUS4-39460 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Ho, Y.T. A1 - Adriani, G A1 - Beyer, Sebastian A1 - Nhan, P.-T. A1 - Kamm, R. D. A1 - Kah, J.C.Y. T1 - A facile method to probe the vascular permeability of nanoparticles in nanomedicine applications N2 - The effectiveness of nanoparticles (NP) in nanomedicine depends on their ability to extravasate from vasculature towards the target tissue. This is determined by their permeability across the endothelial barrier. Unfortunately, a quantitative study of the diffusion permeability coefficients (Pd) of NPs is difficult with in vivo models. Here, we utilize a relevant model of vascular-tissue interface with tunable endothelial permeability in vitro based on microfluidics. Human umbilical vein endothelial cells (HUVECs) grown in microfluidic devices were treated with Angiopoietin 1 and cyclic adenosine monophosphate (cAMP) to vary the Pd of the HUVECs monolayer towards fluorescent polystyrene NPs (pNPs) of different sizes, which was determined from image analysis of their fluorescence intensity when diffusing across the monolayer. Using 70 kDa dextran as a probe, untreated HUVECs yielded a Pd that approximated tumor vasculature while HUVECs treated with 25 μg/mL cAMP had Pd that approximated healthy vasculature in vivo. As the size of pNPs increased, its Pd decreased in tumor vasculature, but remained largely unchanged in healthy vasculature, demonstrating a trend similar to tumor selectivity for smaller NPs. This microfluidic model of vascular-tissue interface can be used in any laboratory to perform quantitative assessment of the tumor selectivity of nanomedicine-based systems. KW - Nanoparticle PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397053 DO - https://doi.org/10.1038/s41598-017-00750-3 SN - 2045-2322 VL - 7 IS - 1 SP - Article 707, 1 EP - 13 PB - Macmillan AN - OPUS4-39705 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schürmann, Robin A1 - Bald, Ilko T1 - Real-time monitoring of plasmon induced dissociative electron transfer to the potential DNA radiosensitizer 8-bromoadenine N2 - The excitation of localized surface plasmons in noble metal nanoparticles (NPs) results in different nanoscale effects such as electric field enhancement, the generation of hot electrons and a temperature increase close to the NP surface. These effects are typically exploited in diverse fields such as surface-enhanced Raman scattering (SERS), NP catalysis and photothermal therapy (PTT). Halogenated nucleobases are applied as radiosensitizers in conventional radiation cancer therapy due to their high reactivity towards secondary electrons. Here, we use SERS to study the transformation of 8-bromoadenine (8BrA) into adenine on the surface of Au and AgNPs upon irradiation with a low-power continuous wave laser at 532, 633 and 785 nm, respectively. The dissociation of 8BrA is ascribed to a hot-electron transfer reaction and the underlying kinetics are carefully explored. The reaction proceeds within seconds or even milliseconds. Similar dissociation reactions might also occur with other electrophilic molecules, which must be considered in the interpretation of respective SERS spectra. Furthermore, we suggest that hot-electron transfer induced dissociation of radiosensitizers such as 8BrA can be applied in the future in PTT to enhance the damage of tumor tissue upon irradiation. KW - SERS KW - Nanoparticles KW - Hot electrons KW - Bromoadenine KW - Catalysis PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-396469 DO - https://doi.org/10.1039/C6NR08695K SN - 2040-3364 SN - 2040-3372 VL - 9 IS - 5 SP - 1951 EP - 1955 PB - RSC AN - OPUS4-39646 LA - eng 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 - 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 - 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 - 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 - 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 - Meyer, Susann A1 - Schröter, Maria-Astrid A1 - Hahn, Marc Benjamin A1 - Solumon, Tihomir A1 - Strum, Heinz A1 - Kunte, Hans-Jörg T1 - Ectoine can enhance structural changes in DNA in vitro N2 - Strand breaks and conformational changes of DNA have consequences for the physiological role of DNA. The natural protecting molecule ectoine is beneficial to entire bacterial cells and biomolecules such as proteins by mitigating detrimental effects of environmental stresses. It was postulated that ectoine-like molecules bind to negatively charged spheres that mimic DNA surfaces. We investigated the effect of ectoine on DNA and whether ectoine is able to protect DNA from damages caused by ultraviolet radiation (UV-A). In order to determine different isoforms of DNA, agarose gel electrophoresis and atomic force microscopy experiments were carried out with plasmid pUC19 DNA. Our quantitative results revealed that a prolonged incubation of DNA with ectoine leads to an increase in transitions from supercoiled (undamaged) to open circular (single-strand break) conformation at pH 6.6. The effect is pH dependent and no significant changes were observed at physiological pH of 7.5. After UV-A irradiation in ectoine solution, changes in DNA conformation were even more pronounced and this effect was pH dependent. We hypothesize that ectoine is attracted to the negatively charge surface of DNA at lower pH and therefore fails to act as a stabilizing agent for DNA in our in vitro experiments. KW - Ectoine KW - DNA KW - UV radiation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-413139 DO - https://doi.org/10.1038/s41598-017-07441-z VL - 7 IS - 1 SP - Article 7170, 1 EP - 10 AN - OPUS4-41313 LA - eng 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 - JOUR A1 - Michalik-Onichimowska, Aleksandra A1 - Kern, Simon A1 - Riedel, Jens A1 - Panne, Ulrich A1 - King, R. A1 - Maiwald, Michael T1 - ‘‘Click” analytics for ‘‘click” chemistry – A simple method for calibration–free evaluation of online NMR spectra N2 - Driven mostly by the search for chemical syntheses under biocompatible conditions, so called "click" chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques possessing short set-up times. Here, we report on a fast and reliable calibration-free online NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement of 1H spectra with a time interval of 20 s per spectrum, and a robust, fully automated algorithm to interpret the obtained data. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in a variety of non-deuterated solvents while its time-resolved behaviour was characterized with step tracer experiments. Overlapping signals in online spectra during thiol-ene coupling could be deconvoluted with a spectral model using indirect hard modeling and were subsequently converted to either molar ratios (using a calibrationfree approach) or absolute concentrations (using 1-point calibration). For various solvents the kinetic constant k for pseudo-first order reaction was estimated to be 3.9 h-1 at 25 °C. The obtained results were compared with direct integration of non-overlapping signals and showed good agreement with the implemented mass balance. KW - Online NMR Spectroscopy KW - Reaction Monitoring KW - Automated Data Evaluation KW - Thiol-ene click chemistry KW - Click Chemistry KW - Process Analytical Technology PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393232 UR - http://www.sciencedirect.com/science/article/pii/S1090780717300575 DO - https://doi.org/10.1016/j.jmr.2017.02.018 VL - 277 SP - 154 EP - 161 PB - Elsevier Inc. CY - Oxford AN - OPUS4-39323 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kern, Simon A1 - Michalik-Onichimowska, Aleksandra A1 - Riedel, Jens A1 - Panne, Ulrich A1 - King, R. A1 - Maiwald, Michael ED - Herwig, Christoph T1 - “Click” analytics for “click” chemistry – a simple method for calibration-free evaluation of online NMR spectra N2 - Currently, research in chemical manufacturing moves towards flexible plug-and-play approaches focusing on modular plants, capable of producing small scales on-demand with short down-times between individual campaigns. This approach allows for efficient use of hardware, a faster optimization of the process conditions, and thus, an accelerated introduction of new products to the market. Driven mostly by the search for chemical syntheses under biocompatible conditions, so-called “click” chemistry rapidly became a growing field of research. The resulting simple one-pot reactions are so far only scarcely accompanied by an adequate optimization via comparably straightforward and robust analysis techniques. Here we report on a fast and reliable calibration-free online high field NMR monitoring approach for technical mixtures. It combines a versatile fluidic system, continuous-flow measurement with a time interval of 20 s per spectrum, and a robust, automated algorithm to interpret the obtained data. All spectra were acquired using a 500 MHz NMR spectrometer (Varian) with a dual band flow probe having a 1/16-inch polymer tubing working as a flow cell. Single scan 1H NMR spectra were recorded with an acquisition time of 5 s, relaxation delay of 15 s. As a proof-of-concept, the thiol-ene coupling between N-boc cysteine methyl ester and allyl alcohol was conducted in non-deuterated solvents while its time-resolved behaviour was characterised with step tracer experiments. Through the application of spectral modeling the signal area for each reactant can be deconvoluted in the online spectra and thus converted to the respective concentrations or molar ratios. The signals which were suitable for direct integration were used herein for comparison purposes of both methods. T2 - 11. Interdisziplinäres Doktorandenseminar CY - Berlin, Germany DA - 12.03.2017 KW - Process Monitoring KW - Online NMR Spectroscopy KW - Indirect Hard Modeling KW - Process Control KW - Process Analytical Technology KW - CONSENS KW - Click Chemistry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435531 SP - 33 EP - 35 PB - Gesellschaft Deutscher Chemiker (GDCh) CY - Frankfurt a. M. AN - OPUS4-43553 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 - GEN A1 - Cohen, Zina A1 - Olszowy-Schlanger, Judith A1 - Hahn, Oliver A1 - Rabin, Ira ED - Wandrey, T1 - Composition analysis of writing materials in Geniza fragments N2 - Our current projects focus on the material analysis of the writing materials kept in the Taylor-Schechter Collection at Cambridge University Library, which houses the largest collection of Cairo Geniza fragments, about 190,000. Although Geniza manuscripts have attracted a great deal of scholarly attention, the material aspects of these documents seem to have been largely neglected. The current study aims to obtain information on the composition of the writing supports and the inks that were used, the production of the original manuscripts and the history of their degradation. The collected data should supplement the description based on Hebrew palaeography and codicology. Moreover, a characterisation of the writing materials would provide insights on trade, local production techniques and social structures. The tabulated results have the potential to be used as geo-chronological markers if sufficient data is collected. For our study, we chose Hebrew legal documents and letters from three communities that co-existed in Fustat (today Cairo) in the 11th century: the Jerusalemite (or ‘Palestinian’) community, the Babylonian community and the Karaites, three different communities with different scribal traditions. In addition to this, we studied non-biblical scrolls attributed to the Palestinian and Babylonian communities. The question we addressed was whether we can correlate the use of a specific type of ink to an objective criterion. For our analysis at Cambridge University Library, we used a number of protocols developed at BAM (Bundesanstalt für Materialforschung und -prüfung) in Berlin and at the Centre for Study of Manuscript Cultures, University of Hamburg (CSMC). These include reflectographic examination followed by non-destructive X-ray fluorescence (XRF) analysis using transportable instruments so that the analysis can be carried out in situ. We have illustrated our approach here by providing two examples. The first one describes our investigation of the leather fragment containing a portion of the Babylonian Talmud on its hair side (TS Misc.26.53.17). The second example illustrates our ability to compare iron-gall inks using the XRF method. In this case, we explored the question of the codicological attribution of three fragments (TS F17.4, TS 12.755 and TS 12.756) to the same Talmud manuscript. KW - Cairo Genizah PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435590 DO - https://doi.org/10.1515/9783110546422-013 VL - 13 SP - 323 PB - de Gruyter CY - Berlin AN - OPUS4-43559 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Ebell, Gino A1 - Burkert, Andreas A1 - Breit, W. A1 - Adams, R. A1 - Oechsner, M. A1 - Hoche, H. A1 - Körber, D. T1 - Technologie- und Sicherheitszuwachs bei der Anwendung von feuerverzinktem Betonstahl zum Ausbau einer nachhaltigen Marktposition im Stahlbetonbau N2 - Die Feuerverzinkung von Betonstahl stellt auf der Grundlage der im Stahlbetonbau geltenden Regelwerke eine zusätzliche Maßnahme zur Steigerung der Dauerhaftigkeit insbesondere bei Korrosionsbeanspruchung infolge Karbonatisierung und/oder Chlorideinwirkung dar. Anders als im Ausland ist die Anwendung von feuerverzinktem Betonstahl in Deutschland bisher kaum verbreitet. Im Rahmen des AiF-Forschungsprojekts IGF 499 „Technologie- und Sicherheitszuwachs bei der Anwendung von feuerverzinktem Betonstahl zum Ausbau einer nachhaltigen Marktposition im Stahlbetonbau“ sollten die einem breiteren Einsatz feuerverzinkter Betonstähle in Deutschland bisher entgegenstehenden offenen Fragestellungen beantwortet werden. Die interdisziplinäre Forschergruppe bestand aus dem Fachgebiet Werkstoffe im Bauwesen, Technische Universität Kaiserslautern (Forschungsstelle 1), mit dem Arbeitsschwerpunkt Fertigungstechnik, der staatlichen Materialprüfungsanstalt Darmstadt an der Technischen Universität Darmstadt (Forschungsstelle 2), mit dem Arbeitsschwerpunkt Werkstofftechnik, und der Bundesanstalt für Materialforschung und –prüfung, Berlin (Forschungsstelle 3), mit dem Arbeitsschwerpunkt Korrosionsschutz. KW - Verzinkter Betonstahl PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402215 SP - 1 EP - 253 PB - AiF-Forschungsvereinigung Gemeinschaftsausschuss Verzinken e.V. (GAV) AN - OPUS4-40221 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mitova, M. A1 - Iliev, M. A1 - Nováková, A. A1 - Gorbushina, Anna A1 - Groudeva, V.I. A1 - Martin-Sanchez, Pedro Maria T1 - Diversity and biocide susceptibility of fungal assemblages dwelling in the Art Gallery of Magura Cave, Bulgaria N2 - Magura Cave, north-western Bulgaria, possesses valuable rock-art paintings made with bat guano and dated from the period between the Eneolithic and Bronze Ages. Since 2008, the Art Gallery is closed to the general public in order to protect the paintings from vandalism, microclimatic changes caused by visitors and artificial illumination, and the consequent growth of fungi and phototrophs. Nevertheless, some tourist visits are allowed under the supervision of cave managers. This study provides the first scientific report on cultivable fungal assemblages dwelling different substrata in the Art Gallery. A total of 78 strains, belonging to 37 OTUs (Ascomycota 81%, Zygomycota 13%, Basidiomycota 5%), were isolated in the study. This fungal diversity was clearly dominated by Penicillium (50% of strains) and Aspergillus (13%). The most relevant visible fungal colonies were detected in sediments rich in bat guano, where, besides Penicillium, other guanophilic fungi such as Mucor, Mortierella, Trichosporon and Trichoderma were dominant. Conversely, scarce fungi were detected on rock surface of painted walls. Based on the biocide susceptibility assay, octylisothiazolinone (OIT) and benzalkonium chloride (BAC) were effective inhibiting the in vitro growth of dominant fungal species in Magura Cave, when applied at concentrations ranged from 100 to 1,000 mg/L. These data provide a valuable knowledge about Magura fungi, and exemplify a type of preliminary test that may be conducted before planning any biocide treatment. However, considering the irreversible effects of biocides on the ecological balance in caves, and the low fungal contamination in painted walls of Magura Cave, there is no reason to use conventional biocides in this cave. Further studies, monitoring microbial communities and microclimatic parameters, should be conducted to improve the knowledge on microbial ecology in Magura Cave and possible human impacts, as well as to allow the early detection of potential microbial outbreaks. KW - Fungi KW - Rock-art caves KW - Biocides PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-397436 DO - https://doi.org/10.5038/1827-806X.46.1.2061 SN - 0392-6672 VL - 46 IS - 1 SP - 67 EP - 80 PB - Scholar Commons CY - Tampa, FL, USA AN - OPUS4-39743 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Goedecke, Caroline A1 - Mülow-Stollin, Ulrike A1 - Hering, S. A1 - Richter, Janine A1 - Piechotta, Christian A1 - Paul, Andrea A1 - Braun, Ulrike T1 - A first pilot study on the sorption of environmental pollutants on various microplastic materials N2 - With the drastic increase in plastic production, the input of plastic particles into the environment has become a recognised problem. Xenobiotics are able to sorb to polymer materials, and this process is further enhanced where they Encounter microplastics (plastic fragments <5 mm). In this work we studied the sorption of metformin, a type-2 diabetes drug, and difenoconazole, a fungicide, onto the virgin polymer materials polyamide (PA), polypropylene (PP), and polystyrene (PS). Additionally, PP was cryo-milled and PA was treated with acid to investigate the influence of an increase in surface area and chemical modification. The material properties were also studied by dynamic scanning calorimetry (DSC), gel permeation chromatography (GPC) and Fourier transform infrared spectroscopy (FTIR). Sorption experiments were performed on the basis of a full factorial design examining the effect of agitation, pH value, and salinity. Experimental results showed that difenoconazole sorbs readily to all microplastics, whereas the more polar analyte metformin did not show any affinity to the materials used. For difenoconazole the governing factor in all cases is agitation, while both pH and salinity exhibited only a slight influence. The modification of polymers leads to enhanced sorption, indicating that an increase in surface area (cryo-milled PP) or inner volume (acid-treated PA) strongly favours adsorption. Moreover, long-term experiments demonstrated that the time until equilibrium is reached depends strongly on the particle size. KW - Difenoconazole KW - Metformin KW - Plastic debris KW - Polymer KW - Dynamic scanning calorimetry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402393 DO - https://doi.org/10.4172/2380-2391.1000191 SN - 2380-2391 VL - 4 IS - 1 SP - Article 1000191, 1 EP - 8 PB - Omics International CY - Los Angeles AN - OPUS4-40239 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Seuthe, T. A1 - Mermillod-Blondin, A. A1 - Grehn, M. A1 - Bonse, Jörn A1 - Wondraczek, L. A1 - Eberstein, M. T1 - Structural relaxation phenomena in silicate glasses modifed by irradiation with femtosecond laser pulses N2 - Structural relaxation phenomena in binary and multicomponent lithium silicate glasses were studied upon irradiation with femtosecond (fs) laser pulses (800 nm central wavelength, 130 fs pulse duration) and subsequent thermal annealing experiments. Depending on the annealing temperature, micro-Raman spectroscopy analyses evidenced different relaxation behaviours, associated to bridging and non-bridging oxygen structures present in the glass network. The results indicate that the mobility of lithium ions is an important factor during the glass modification with fs-laser pulses. Quantitative phase contrast imaging (spatial light interference microscopy) revealed that these fs-laser induced structural modifications are closely related to local changes in the refractive index of the material. The results establish a promising strategy for tailoring fs-laser sensitivity of glasses through structural mobility. KW - Femtosecond laser KW - Silicate glasses KW - Raman spectroscopy KW - Structural relaxation KW - Refractive index PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-393045 DO - https://doi.org/10.1038/srep43815 SN - 2045-2322 VL - 7 SP - 43815, 1 EP - 43815, 10 PB - Nature Publishing Group CY - London, UK AN - OPUS4-39304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mull, Birte A1 - Möhlmann, L. A1 - Wilke, Olaf T1 - Photocatalytic degradation of toluene, butyl acetate and limonene under UV and visible light with titanium dioxide-graphene oxide as photocatalyst N2 - Photocatalysis is a promising technique to reduce volatile organic compounds indoors. Titanium dioxide (TiO2) is a frequently-used UV active photocatalyst. Because of the lack of UV light indoors, TiO2 has to be modified to get its working range shifted into the visible light spectrum. In this study, the photocatalytic degradation of toluene, butyl acetate and limonene was investigated under UV LED light and blue LED light in emission test chambers with catalysts either made of pure TiO2 or TiO2 modified with graphene oxide (GO). TiO2 coated with different GO amounts (0.75%–14%) were investigated to find an optimum ratio for the photocatalytic degradation of VOC in real indoor air concentrations. Most experiments were performed at a relative humidity of 0% in 20 L emission test chambers. Experiments at 40% relative humidity were done in a 1 m³ emission test chamber to determine potential byproducts. Degradation under UV LED light could be achieved for all three compounds with almost all tested catalyst samples up to more than 95%. Limonene had the highest degradation of the three selected volatile organic compounds under blue LED light with all investigated catalyst samples. KW - Photocatalysis KW - Emission test chamber KW - Volatile organic compound KW - VOC KW - Degradation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-402955 DO - https://doi.org/10.3390/environments4010009 SN - 2076-3298 VL - 4 IS - 1 SP - Article 9, 1 EP - 9 PB - MDPI CY - Basel AN - OPUS4-40295 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - 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 - 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 - Doublet, V. A1 - Poeschl, Y. A1 - Gogol-Döring, A. A1 - Alaux, C. A1 - Annoscia, D. A1 - Aurori, C. A1 - Barribeau, S. M. A1 - Bedoya-Reina, O. C. A1 - Brown, M. J. F. A1 - Bull, J. C. A1 - Flenniken, M. L. A1 - Galbraith, D. A. A1 - Genersch, E. A1 - Gisder, S. A1 - Grosse, I. A1 - Holt, H. L. A1 - Hultmark, D. A1 - Lattorff, H. M. G. A1 - Le Conte, Y. A1 - Manfredini, F. A1 - McMahon, Dino Peter A1 - Moritz, R. F. A. A1 - Nazzi, F. A1 - Niño, E. L. A1 - Nowick, K. A1 - Van Rij, R. P. A1 - Paxton, R. J. A1 - Grozinger, C. M. T1 - Unity in defence: honeybee workers exhibit conserved molecular responses to diverse pathogens N2 - Background: Organisms typically face infection by diverse pathogens, and hosts are thought to have developed specific responses to each type of pathogen they encounter. The advent of transcriptomics now makes it possible to test this hypothesis and compare host gene expression responses to multiple pathogens at a genome-wide scale. Here, we performed a meta-analysis of multiple published and new transcriptomes using a newly developed bioinformatics approach that filters genes based on their expression profile across datasets. Thereby, we identified common and unique molecular responses of a model host species, the honey bee (Apis mellifera), to its major pathogens and parasites: the Microsporidia Nosema apis and Nosema ceranae, RNA viruses, and the ectoparasitic mite Varroa destructor, which transmits viruses. Results: We identified a common suite of genes and conserved molecular pathways that respond to all investigated pathogens, a result that suggests a commonality in response mechanisms to diverse pathogens. We found that genes differentially expressed after infection exhibit a higher evolutionary rate than non-differentially expressed genes. Using our new bioinformatics approach, we unveiled additional pathogen-specific responses of honey bees; we found that apoptosis appeared to be an important response following microsporidian infection, while genes from the immune signalling pathways, Toll and Imd, were differentially expressed after Varroa/virus infection. Finally, we applied our bioinformatics approach and generated a gene co-expression network to identify highly connected (hub) genes that may represent important mediators and regulators of anti-pathogen responses. Conclusions: Our meta-analysis generated a comprehensive overview of the host metabolic and other biological processes that mediate interactions between insects and their pathogens. We identified key host genes and pathways that respond to phylogenetically diverse pathogens, representing an important source for future functional studies as well as offering new routes to identify or generate pathogen resilient honey bee stocks. The statistical and bioinformatics approaches that were developed for this study are broadly applicable to synthesize information across transcriptomic datasets. These approaches will likely have utility in addressing a variety of biological questions. KW - Coexpression KW - Apis mellifera KW - Nosema KW - Varroa destructor KW - DWV KW - IAPV KW - RNA virus KW - Meta-analysis KW - Transcriptomics PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-410439 DO - https://doi.org/10.1186/s12864-017-3597-6 SN - 1471-2164 VL - 18 SP - 207 EP - 224 AN - OPUS4-41043 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 - JOUR A1 - Tuma, Dirk A1 - Kumbhar, V. S. A1 - Lee, Y. R. A1 - Ra, C. S. A1 - Min, B.-K. A1 - Shim, J.-J. T1 - Modified chemical synthesis of MnS nanoclusters on nickel foam for high performance all-solid-state asymmetric supercapacitors N2 - Novel MnS nanoclusters were synthesized on nickel foam (NF) using a successive ionic layer adsorption and reaction (SILAR) method. MnS nanoclusters with different sizes were obtained by varying the number of deposition cycles. The crystal structure, chemical composition, and surface microstructure of the electrodes were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field Emission scanning electron microscopy, and high-resolution transmission electron microscopy. The electrochemical behavior of the MnS nanoclusters was examined by cyclic voltammetry, galvanostatic charge–discharge, cycling test, and electrochemical impedance spectroscopy. The MnS nanoclusters prepared with 90 SILAR cycles showed the best supercapacitance in a 6 M KOH aqueous electrolyte with a specific capacitance of 828 F/g at a scan rate of 5 mV/s and cycling stability of 85.2 % after 5000 charge–discharge cycles. Moreover, an asymmetric supercapacitor (ASC) was assembled with the as-prepared MnS electrode on NF as the positive electrode, hydrothermally prepared reduced graphene oxide (rGO) on NF as the negative electrode, and PVA–KOH gel as the electrolyte. The MnS@NF//rGO@NF ASC showed excellent electrochemical performance with maximum energy and power densities of 34.1 Wh/kg and 12.8 kW/kg, respectively. The ASC also showed a capacitive retention of 86.5 % after 2000 charge–discharge cycles, highlighting its practical application for energy storage. KW - Nanocluster KW - Electrochemical behavior KW - Asymmetric supercapacitor KW - Graphene oxide PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403147 DO - https://doi.org/10.1039/c7ra00772h SN - 2046-2069 VL - 7 IS - 27 SP - 16348 EP - 16359 PB - The Royal Society of Chemistry CY - London AN - OPUS4-40314 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Maul, Ronald A1 - Greer, B. A1 - Campbell, K. A1 - Elliott, C.T. T1 - Detection of freshwater cyanotoxins and measurement of masked microcystins in tilapia from Southeast Asian aquaculture farms N2 - Recently, there has been a rise in freshwater harmful algal blooms (HABs) globally, as well as increasing aquaculture practices. HABs can produce cyanotoxins, many of which are hepatotoxins. An ultra-performance liquid chromatography tandem mass spectrometry method was developed and validated for nine cyanotoxins across three classes including six microcystins, nodularin, cylindrospermopsin and anatoxin-a. The method was used to analyse free cyanotoxin(s) in muscle (n = 34), liver (n = 17) and egg (n = 9) tissue samples of 34 fish sourced from aquaculture farms in Southeast Asia. Conjugated microcystin was analysed by Lemieux oxidation to ascertain the total amount of microcystin present in muscle. Some tilapia accumulated free microcystin-LR in the muscle tissue at a mean of 15.45 μg/kg dry weight (dw), with total microcystin levels detected at a mean level of 110.1 μg/kg dw, indicating that the amount of conjugated or masked microcystin present in the fish muscle accounted for 85% of the total. Higher levels of cyanotoxin were detected in the livers, with approximately 60% of those tested being positive for microcystin-LR and microcystin-LF, along with cylindrospermopsin. Two fish from one of the aquaculture farms contained cylindrospermopsin in the eggs; the first time this has been reported. The estimated daily intake for free and total microcystins in fish muscle tissue was 2 and 14 times higher, respectively, than the tolerable daily intake value. This survey presents the requirement for further monitoring of cyanotoxins, including masked microcystins, in aquaculture farming in these regions and beyond, along with the implementation of guidelines to safeguard human health. KW - Harmful algal bloom KW - UPLC-MS/MS KW - Bioaccumulation KW - Human health PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404669 DO - https://doi.org/10.1007/s00216-017-0352-4 SN - 1618-2642 SN - 1618-2650 VL - 409 IS - 16 SP - 4057 EP - 4069 PB - Springer CY - Heidelberg AN - OPUS4-40466 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yasutaka, T. A1 - Imoto, Y. A1 - Kurosawa, A. A1 - Someya, M. A1 - Higashino, K. A1 - Kalbe, Ute A1 - Sakanakura, H. T1 - Effects of colloidal particles on the results and reproducibility of batch leaching tests for heavy metal-contaminated soil N2 - A simple batch test leaching procedure is used in many countries, as a compliance test, to evaluate the leaching of mainly inorganic substances from soil. However, agitating certain types of soil and then passing the solution through a membrane filter with 0.45-µm pores yields filtrates that have been colored by the colloidal particles. These colloids might affect the results of the inorganic substances obtained in the batch tests. In this study, we evaluated the effects of colloidal particles on the results and the reproducibility of batch tests on contaminated soil using different agitation methods and membrane filters with different pore sizes. The leaching behaviors of As, Pb, Se, F and Cl from three types of soil were studied. The As and Pb concentrations in the leachates of some types of soil were clearly affected by the amount of colloidal particles with a diameter of 0.10–0.45 µm and by the agitation method used. This was probably because As and Pb were present mainly in the particulate form in the leachate that had been passed through a membrane filter with 0.45-µm pores. This is not the case for every type of soil. The results of batch leaching tests showed that not only dissolved but also colloidal forms with a diameter of 0.10–0.45 µm might be included and that the existence of colloidal particles in the leachate decreases the batch leaching test reproducibility. KW - Leaching KW - Contaminated soil KW - Heavy metals KW - Colloids PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-429940 UR - https://www.sciencedirect.com/science/article/pii/S0038080617301166#! DO - https://doi.org/10.1016/j.sandf.2017.08.014 SN - 0038-0806 VL - 57 IS - 5 SP - 861 EP - 871 PB - Elsevier B.V. AN - OPUS4-42994 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 - Lauer, Franziska A1 - Seifert, Stephan A1 - Kneipp, Janina A1 - Weidner, Steffen T1 - Simplifying the Preparation of Pollen Grains for MALDI-TOF MS Classification N2 - Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS) is a well-implemented analytical technique for the investigation of complex biological samples. In MS, the sample preparation strategy is decisive for the success of the measurements. Here, sample preparation processes and target materials for the investigation of different pollen grains are compared. A reduced and optimized sample preparation process prior to MALDI-TOF measurement is presented using conductive carbon tape as target. The application of conductive tape yields in enhanced absolute signal intensities and mass spectral pattern information, which leads to a clear separation in subsequent pattern analysis. The results will be used to improve the taxonomic differentiation and identification, and might be useful for the development of a simple routine method to identify pollen based on mass spectrometry. KW - PCA KW - MALDI-TOF MS KW - Conductive carbon tape KW - Pollen KW - Sample pretreatment PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-392885 UR - http://www.mdpi.com/1422-0067/18/3/543/ DO - https://doi.org/10.3390/ijms18030543 SN - 1422-0067 VL - 18 IS - 3 SP - 543 EP - 554 PB - MDPI AG CY - Basel, Switzerland AN - OPUS4-39288 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Meyer, Susann A1 - Schröter, Maria-Astrid A1 - Seitz, H. A1 - Kunte, Hans-Jörg A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - Direct electron irradiation of DNA in fully aqueous environment. Damage determination in combination with Monte Carlo simulations N2 - We report on a study in which plasmid DNA in water was irradiated with 30 keV electrons generated by a scanning electron microscope and passed through a 100 nm thick Si3N4 membrane. The corresponding Monte Carlo simulations suggest that the kinetic energy spectrum of the electrons throughout the water is dominated by low energy electrons (<100 eV). The DNA radiation damage, single-strand breaks (SSB) and double-strand breaks (DSB), was determined by electrophoresis. The median lethal dose of D1/2 = 1.7 ± 0.3 Gy was found to be much smaller compared to partially or fully hydrated DNA irradiated under vacuum conditions. The ratio of DSB to SSB was found to be (1:12) as compared to 1:88) found for hydrated DNA. Our method enables quantitative measurements of radiation damage to biomolecules (DNA, proteins) in solutions under varying conditions (pH, salinity, cosolutes) for an electron energy range which is difficult to probe by standard methods. KW - Plasmid DNA in water KW - Monte Carlo simulation KW - Low energy electrons KW - DNA radiation damage KW - Single-strand break (SSB) KW - Double-strand break (DSB) KW - Lethal dose KW - Radiation damage to biomolecules KW - Solutions (pH, salinity, cosolutes) PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-386981 DO - https://doi.org/10.1039/C6CP07707B SN - 1463-9076 SN - 1463-9084 VL - 19 IS - 3 SP - 1798 EP - 1805 PB - Royal Society of Chemistry AN - OPUS4-38698 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Meyer, Susann A1 - Kunte, Hans-Jörg A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - Measurements and simulations of microscopic damage to DNA in water by 30 keV electrons: A general approach applicable to other radiation sources and biological targets N2 - The determination of the microscopic dose-damage relationship for DNA in an aqueous environment is of a fundamental interest for dosimetry and applications in radiation therapy and protection. We combine geant4 particle-scattering simulations in water with calculations concerning the movement of biomolecules to obtain the energy deposit in the biologically relevant nanoscopic volume. We juxtaposition these results to the experimentally determined damage to obtain the dose-damage relationship at a molecular level. This approach is tested for an experimentally challenging system concerning the direct irradiation of plasmid DNA (pUC19) in water with electrons as primary particles. Here a microscopic target model for the plasmid DNA based on the relation of lineal energy and radiation quality is used to calculate the effective target volume. It was found that on average fewer than two ionizations within a 7.5-nm radius around the sugar-phosphate backbone are sufficient to cause a single strand break, with a corresponding median lethal energy deposit being E1/2=6±4 eV. The presented method is applicable for ionizing radiation (e.g., γ rays, x rays, and electrons) and a variety of targets, such as DNA, proteins, or cells. KW - DNA KW - Radiation damage KW - Dosimetry KW - DNA radiation damage KW - Single-strand break (SSB) KW - Double-strand break (DSB) KW - Low energy electrons KW - Monte Carlo simulation KW - Radiation damage to biomolecules KW - Plasmid DNA in water KW - Lethal dose KW - Solutions (pH, salinity, cosolutes) KW - Geant4 KW - Microdosimetry PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404244 DO - https://doi.org/10.1103/PhysRevE.95.052419 SN - 2470-0045 SN - 2470-0053 VL - 95 IS - 5 SP - 052419-1 EP - 052419-8 PB - American Physical Society CY - USA AN - OPUS4-40424 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Hahn, Marc Benjamin A1 - Susann, Meyer A1 - Schröter, Maria-Astrid A1 - Kunte, Hans-Jörg A1 - Solomun, Tihomir A1 - Sturm, Heinz T1 - DNA protection by ectoine from ionizing radiation: molecular mechanisms N2 - Ectoine, a compatible solute and osmolyte, is known to be an effective protectant of biomolecules and whole cells against heating, freezing and extreme salinity. Protection of cells (human keratinocytes) by ectoine against ultraviolet radiation has also been reported by various authors, although the underlying mechanism is not yet understood. We present the first electron irradiation of DNA in a fully aqueous environment in the presence of ectoine and at high salt concentrations. The results demonstrate effective protection of DNA by ectoine against the induction of single-strand breaks by ionizing radiation. The effect is explained by an increase in low-energy electron scattering at the enhanced free-vibrational density of states of water due to ectoine, as well as the use of ectoine as an ˙OH-radical scavenger. This was demonstrated by Raman spectroscopy and electron paramagnetic resonance (EPR). KW - Ectoine KW - DNA KW - Radiation protection KW - Ionizing radiation KW - Compatible solute KW - Biomolecules KW - Sodium chloride KW - Aqueous solution KW - Hydroxyectoine KW - Raman spectroscopy KW - Electron irradiation KW - Cancer KW - Radical scavenger KW - Low energy electrons KW - Hydroxyl radical KW - OH-radical KW - Ectoin KW - UV radiation KW - Sun KW - Salt KW - Radiation therapy PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-419332 UR - http://pubs.rsc.org/en/content/articlehtml/2017/cp/c7cp02860a DO - https://doi.org/10.1039/C7CP02860A SN - 1463-9076 VL - 19 IS - 37 SP - 25717 EP - 25722 PB - Royal Society of Chemistry CY - United Kingdom AN - OPUS4-41933 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Breitenbach, Romy A1 - Silbernagl, Dorothee A1 - Toepel, J. A1 - Sturm, Heinz A1 - Broughton, William J. A1 - Sassaki, G. L. A1 - Gorbushina, Anna T1 - Corrosive extracellular polysaccharides of the rock-inhabiting model fungus Knufia petricola N2 - Melanised cell walls and extracellular polymeric matrices protect rock-inhabiting microcolonial fungi from hostile environmental conditions. How extracellular polymeric substances (EPS) perform this protective role was investigated by following development of the model microcolonial black fungus Knufia petricola A95 grown as a sub-aerial biofilm. Extracellular substances were extracted with NaOH/formaldehyde and the structures of two excreted polymers studied by methylation as well as NMR analyses. The main polysaccharide (~ 80%) was pullulan, also known as α-1,4-; α-1,6-glucan, with different degrees of polymerisation. Αlpha-(1,4)-linked-Glcp and α-(1,6)-linked-Glcp were present in the molar ratios of 2:1. A branched galactofuromannan with an α-(1,2)-linked Manp main chain and a β-(1,6)-linked Galf side chain formed a minor fraction (~ 20%). To further understand the roles of EPS in the weathering of minerals and rocks, viscosity along with corrosive properties were studied using atomic force microscopy (AFM). The kinetic viscosity of extracellular K. petricola A95 polysaccharides (≈ 0.97 × 10-6 m2 s-1) ranged from the equivalent of 2% (w/v) to 5% glycerine, and could thus profoundly affect diffusion-dominated processes. The corrosive nature of rock-inhabiting fungal EPS was also demonstrated by its effects on the aluminium coating of the AFM cantilever and the silicon layer below. KW - Corrosion KW - EPS KW - Melanised microcolonial fungi (MCF) KW - Pullulan KW - Sub-aerial biofilms (SAB) KW - α-1,4- and α-1,6-glucans KW - AFM cantilever vibration KW - Nanoviscosity KW - Nanocorrosion of aluminium and silicon PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-435910 DO - https://doi.org/10.1007/s00792-017-0984-5 SN - 1433-4909 SN - 1431-0651 VL - 22 IS - 2 SP - 165 EP - 175 PB - Springer CY - Berlin AN - OPUS4-43591 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schröter, Maria-Astrid A1 - Meyer, Susann A1 - Hahn, Marc Benjamin A1 - Solomun, Tihomir A1 - Sturm, Heinz A1 - Kunte, Hans-Jörg T1 - Ectoine protects DNA from damage by ionizing radiation N2 - Ectoine plays an important role in protecting biomolecules and entire cells against environmental stressors such as salinity, freezing, drying and high temperatures. Recent studies revealed that ectoine also provides effective protection for human skin cells from damage caused by UV-A radiation. These protective properties make ectoine a valuable compound and it is applied as an active ingredient in numerous pharmaceutical devices and cosmetics. Interestingly, the underlying mechanism resulting in protecting cells from radiation is not yet fully understood. Here we present a study on ectoine and its protective influence on DNA during electron irradiation. Applying gel electrophoresis and atomic force microscopy, we demonstrate for the first time that ectoine prevents DNA strand breaks caused by ionizing electron radiation. The results presented here point to future applications of ectoine for instance in cancer radiation therapy. KW - Plasmid DNA pUC19 KW - Electron irradiation 30 [kV] KW - Effective irradiation dose 0.2-16 [Gy] KW - Gel electrophoresis KW - AFM intermittent contact KW - Radioprotector ectoine KW - Compatible solute PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-428287 DO - https://doi.org/10.1038/s41598-017-15512-4 SN - 2045-2322 VL - 7 IS - 1 SP - 15272, 1 EP - 15272, 7 PB - Nature AN - OPUS4-42828 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 - RPRT A1 - Wohlleben, W. A1 - Mielke, Johannes A1 - Hodoroaba, Vasile-Dan A1 - Zimathies, Annett A1 - Bianchin, A. A1 - Lecloux, A. A1 - Roebben, G. A1 - Rauscher, H. A1 - Gibson, N. T1 - Development of an integrated approach based on validated and standardized methods to support the implementation of the EC recommendation for a definition of nanomaterial N2 - The VSSA approach has the important advantage over classifying, imaging and counting techniques that it does not involve dispersion protocols. Further, the BET technique as the basis for VSSA determination it is in widespread use, generates low costs and is specified for many commercial materials. Finally, the same equipment allows for a deeper analysis by full isotherm evaluation. The present deliverable assesses all NanoDefine powders, supplemented by further real-world materials (in total 26 powders), and quantitatively compares the relationship between the median size (by Electron Microscopy – considered as benchmark for the EC nanomaterial definition) vs. the size derived from VSSA. The VSSA method mitigates the challenges of EM to assess the thickness of platelets, but worked as well on fibbers and particles of irregular shapes. A screening strategy is proposed. If applied to the further data from real-world materials as validation set, this screening does achieve a correct classification, leaving only borderline materials for tier 2 assessment. KW - Nanomaterial KW - Classification KW - Regulation KW - VSSA KW - Size measurement KW - Particle size PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-398938 DO - https://doi.org/10.1007/s11051-017-3741-x SP - 1 EP - 26 PB - The NanoDefine Consortium CY - Wageningen, The Netherlands AN - OPUS4-39893 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 - Mishurova, Tatiana A1 - Cabeza, Sandra A1 - Artzt, Katia A1 - Haubrich, J. A1 - Klaus, M. A1 - Genzel, Ch. A1 - Requena, G. A1 - Bruno, Giovanni T1 - An Assessment of Subsurface Residual Stress Analysis in SLM Ti-6Al-4V N2 - Ti-6Al-4V bridges were additively fabricated by selective laser melting (SLM) under different scanning speed conditions, to compare the effect of process energy density on the residual stress state. Subsurface lattice strain characterization was conducted by means of synchrotron diffraction in energy dispersive mode. High tensile strain gradients were found at the frontal surface for samples in an as-built condition. The geometry of the samples promotes increasing strains towards the pillar of the bridges. We observed that the higher the laser energy density during fabrication, the lower the lattice strains. A relief of lattice strains takes place after heat treatment. KW - Selective laser melting KW - Additive manufacturing KW - Heat treatment KW - Ti-6Al-4V KW - Synchrotron X-ray diffraction KW - Residual stress PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-395759 DO - https://doi.org/10.3390/ma10040348 SN - 1996-1944 VL - 10 IS - 4 SP - Article 348, 1 EP - 14 AN - OPUS4-39575 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 - CONF A1 - Shashev, Yury A1 - Kupsch, Andreas A1 - Lange, Axel A1 - Evsevleev, Sergei A1 - Britzke, Ralf A1 - Bruno, Giovanni A1 - Müller, Bernd R. T1 - Talbot-Lau Röntgen-Interferometrie für die zerstörungsfreie Prüfung N2 - Im vergangenen Jahrzehnt sind gitterinterferometrische Röntgenabbildungen zunehmend in den Fokus des Interesses gerückt. Sie sind insbesondere dann Vorteil, wenn der in der Standardradiographie erreichbare Kontrast nicht genügt, schwach absorbierende Mikro- und Nanostrukturen abzubilden. Auf Kosten mehrerer Aufnahmen gestattet die Talbot-Lau Gitterinterferometrie, die Beiträge aus Absorption, Refraktion und (refraktiver) Streuung zu trennen. Dazu werden die Störungen der Interferenzmuster von Phasengittern ausgewertet. Im Gegensatz zu einer Vielzahl anderer refraktionsbasierter Abbildungsmethoden kann diese Technik mit konventionellen Röntgenröhren (mit divergenter, polychromatischer Strahlung) angewendet werden. Damit ist die Technik geeignet, typische ZfP-Fragestellungen zu lösen. Hier stellen wir Untersuchungen zur Effizienz von Phasengittern vor. Die Visibilität (d.h. die Höhe der Oszillation im Interferenzmuster) wird als Funktion verschiedener geometrischer Parameter verfolgt. Eine Rotation um die Achse parallel zu den Gitterstegen ändert die Form des Gitterprofils (d.h. die Verteilung der Phasenschiebungen). Die kontinuierliche Variation des Winkels und des Detektionsabstandes führt zur Identifikation von ausgezeichneten Kombinationen mit maximaler Visibilität, wobei die Abstände deutlich geringer sind als im Standardaufbau mit senkrechter Gitterbestrahlung. Unsere Studie umfasst Simulationen für monochromatische Quelle und den Vergleich zu experimentellen Ergebnissen mit der Synchrotronstrahlung. In der Literatur wurden die Vorteile der Talbot-Lau Interferometrie für die zerstörungsfreie Prüfung von Faserkompositen und Verbundwerkstoffen demonstriert. Hier werden als Beispiele Messungen an Aluminiumtitanat (Al2TiO5) Pulver gezeigt. T2 - DGZfP 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Gitterinterferometrische Röntgenabbildung KW - Phasengitter KW - Talbot-Lau Interferometrie KW - Zerstörungsfreie Prüfung PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-404691 SP - 1 EP - 10 PB - DGZfP AN - OPUS4-40469 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Johann, Sergej A1 - Strangfeld, Christoph A1 - Müller, Maximilian A1 - Mieller, Björn A1 - Bartholmai, Matthias T1 - RFID sensor systems embedded in concrete – validation experiments for long-term monitoring N2 - Structural Health Monitoring (SHM) is an important part of buildings surveillance and maintenance to detect material failure as early as possible and to contribute in protection of structures and their users. The implementation of Radio Frequency Identification (RFID) sensor systems without cable connection and battery into building components offers innovative possibilities to enable long-term in-situ SHM of addressed structures, bridges. The objectives of the presented study are complete embedding of RFID sensors systems in concrete, full passive communication with the systems, at best for the whole life span of structures. One challenge for this task is the highly alkaline environment in concrete, which requires non-degrading and robust encapsulation. Further Requirements are passive communication and energy supply, appropriate antenna design, placement and fixation in concrete, and the selection and implementation of sensors and connections. The concept is to develop and optimize a simple and robust system, which meets the requirements, as well as comprehensive validation in concrete specimen and real world applications. Two different systems were developed (HF and UHF RFID, respectively). First tasks were the implementation of analog sensors using the superposition principle for the signal adaption. Investigation of suitable materials for robust encapsulation and sensor protection against basic environments. Four materials were investigated in pH 13 solution for 14 days - 3D-Printer-Polymer was completely resolved - PVC has no noticeable decrease in weight - (VitaPro) glass filter for the sensor protector, has weight loss 2.7 % - The epoxy resin has increased by 1.8 % due to moisture expansion Different concrete samples were prepared for the validation of the systems. RFID sensors were embedded in different integration depths. Investigate the energy- and data transfer through concrete, also with varying moisture content. Additionally, signal strength data was used to optimize and validate the antenna characteristics in concrete. Next steps are to guarantee a sufficient energy supply for UHF RFID systems embedded in different concrete mixtures and further embedding the HF and UHF RFID systems in real bridges and buildings to validate the long term monitoring. T2 - DGZfP-Jahrestagung 2017 CY - Koblenz, Germany DA - 22.05.2017 KW - Smart structures KW - RFID sensors KW - Long-term requirements KW - Structural health monitoring KW - Passive RFID KW - Sensor requirements KW - Sensors in concrete PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-403496 UR - https://www.ndt.net/?id=21499 SN - 1435-4934 VL - 22 IS - 9 SP - 1 EP - 7 PB - NDT.net CY - Kirchwald AN - OPUS4-40349 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Johann, Sergej A1 - Strangfeld, Christoph A1 - Müller, Maximilian A1 - Mieller, Björn A1 - Bartholmai, Matthias T1 - RFID sensor systems embedded in concrete – Validation experiments for long-term monitoring T1 - RFID Sensorsysteme eingebettet in Beton – Validierungsexperimente zum Langzeitmonitoring N2 - Structural Health Monitoring (SHM) is an important part of buildings surveillance and maintenance to detect material failure as early as possible and to contribute in protection of structures and their users. The implementation of Radio Frequency Identification (RFID) sensor systems without cable connection and battery into building components offers innovative possibilities to enable long-term in-situ SHM of addressed structures, bridges. The objectives of the presented study are complete embedding of RFID sensors systems in concrete, full passive communication with the systems, at best for the whole life span of structures. One challenge for this task is the highly alkaline environment in concrete, which requires non-degrading and robust encapsulation. Further Requirements are passive communication and energy supply, appropriate antenna design, placement and fixation in concrete, and the selection and implementation of sensors and connections. The concept is to develop and optimize a simple and robust system, which meets the requirements, as well as comprehensive validation in concrete specimen and real world applications. Two different systems were developed (HF and UHF RFID, respectively). First tasks were the implementation of analog sensors using the superposition principle for the signal adaption. Investigation of suitable materials for robust encapsulation and sensor protection against basic environments. Four materials were investigated in pH13 solution for 14 days - 3D-Printer-Polymer was completely resolved - PVC has no noticeable decrease in weight - (VitaPro) glass filter for the sensor protector, has weight loss 2.7% - The epoxy resin has increased by 1.8% due to moisture expansion Different concrete samples were prepared for the validation of the systems. RFID sensors were embedded in different integration depths. Investigate the energy- and data transfer through concrete, also with varying moisture content. Additionally, signal strength data was used to optimize and validate the antenna characteristics in concrete. Next steps are to guarantee a sufficient energy supply for UHF RFID systems embedded in different concrete mixtures and further embedding the HF and UHF RFID systems in real bridges and buildings to validate the long term monitoring. KW - RFID sensors KW - Structural health monitoring KW - Sensors in concrete KW - Smart structures KW - Sensor requirements PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-418331 UR - http://www.ndt.net/?id=21499 SN - 1435-4934 VL - 22 IS - 9 SP - Artikel 8, 1 EP - 7 PB - NDT.net CY - Bad Breisig AN - OPUS4-41833 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 -