TY - JOUR A1 - Moldenhauer, Laura A1 - Helmerich, Rosemarie A1 - Köppe, Enrico A1 - Haamkens, Frank A1 - Wittmann, Jochen ED - Emri, Igor T1 - Experimental feasibility study about moisture in building materials measured with Bluetooth N2 - Structural health monitoring contributes to early damage detection in the built infrastructure. During the last two decades, sensor networks transferred from wired to wireless sensor networks. Several methods exist to measure moisture in building materials. Most of the introduced commercial moisture measurement methods provide information about the local or near surface moisture. A feasibility study is presented to demonstrate, how the Received Signal Strength Indicator (RSSI) of a Bluetooth Low Energy (BLE) signal, transmitted from the BLE-module embedded in building materials, correlate with changing moisture content. The feasibility of this influence was investigated in the presented study. The maximum and minimum RSSI were systematically recorded and analysed. T2 - 33nd Danubia Adria Symposium on Advances in Experimental Mechanics CY - Portoroz, Slovenia DA - 20.09.2016 KW - BLE KW - Long-Term Monitoring KW - Network KW - Structural Health Monitoring KW - Moisture Measurement KW - RSSI KW - Bluetooth Low Energy KW - Sensor PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S2214785317308398 DO - https://doi.org/10.1016/j.matpr.2017.06.053 SN - 2214-7853 VL - 4 IS - 5, Part 1 SP - 5889 EP - 5892 PB - Elsevier Ltd. AN - OPUS4-41585 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sun, C. A1 - Tian, X. A1 - Wang, L. A1 - Liu, Y. A1 - Wirth, Cynthia A1 - Günster, Jens A1 - Li, D. A1 - Jin, Z. T1 - Effect of particle size gradation on the performance of glass-ceramic 3D printing process N2 - Particle size gradation is regarded as an effective method for overcoming the contradicting requirements in three-dimensional printing (3DP). In present work, particle size gradation was optimized to obtain both acceptable flowability of the powder material and high-strength 3D-printed glass-ceramic products. The effect of gradation on the printing process, sintering process and performance of the 3D-printed glass-ceramic products was investigated comprehensively. The glass-ceramic powders with three size ranges were mixed in certain proportions and applied to print parts. The result showed parts printed with powder mixed by 60 wt% 45–100 µm and 40 wt% 0–25 µm particles had satisfactory density of 1.60 g/cm³ and bending strength of 13.8 MPa. The flowability decreased with an increasing proportion of fine particles. Part density was determined by the powder bulk density in the powder bed as well as the shrinkage during sintering while strength of part was found to be dependent on the sintering degree. KW - Flowability KW - Glass-ceramic KW - Particle size gradation KW - Three-dimensional printing KW - Mechanical properties PY - 2017 DO - https://doi.org/10.1016/j.ceramint.2016.09.197 SN - 0272-8842 VL - 43 IS - 1 SP - 578 EP - 584 PB - Elsevier AN - OPUS4-39783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mady, A. H. A1 - Baynosa, M. L. A1 - Tuma, Dirk A1 - Shim, J.-J. T1 - Facile microwave-assisted green synthesis of Ag-ZnFe2O4@rGO nanocomposites for efficient removal of organic dyes under UV- and visible-light irradiation N2 - Nanocomposites of Ag-ZnFe2O4@reduced graphene oxide (rGO) were synthesized using a one-pot microwave-assisted self-assembly method. The morphology and structure of the Ag-ZnFe2O4@rGO nanocomposites were characterized. The nanocomposites formed with 15.2 wt% rGO showed excellent adsorption properties and high photocatalytic activity for the degradation of methylene blue (MB), rhodamine B (RhB), and methyl orange (MO). The synergistic interactions between Ag, ZnFe2O4, and rGO decreased the aggregation of the nanoparticles (NPs) and increased the surface area, resulting in better absorption in both UV and visible light. Such a structure was helpful for separating the photoexcited electron-hole pairs and accelerating electron transfer. Electrochemical impedance spectroscopy (EIS) revealed a smaller resistance in the solid-state interface layer and charge transfer on the composite surface than that of the bare ZnFe2O4 NPs and ZnFe2O4@rGO nanocomposite. The Ag-ZnFe2O4@rGO nanocomposite could be recovered easily by a magnet and reused five times with no significant decrease in photocatalytic activity. The as-prepared Ag-ZnFe2O4@rGO nanocomposite catalyst could be applied to the removal of hard-to-degrade waste materials owing to its high efficiency in both UV and visible light and its excellent reusability. KW - nanoparticles KW - microwave synthesis KW - photocatalysis PY - 2017 DO - https://doi.org/10.1016/j.apcatb.2016.10.033 SN - 0926-3373 SN - 1873-3883 VL - 203 SP - 416 EP - 427 PB - Elsevier B. V. CY - Amsterdam AN - OPUS4-37962 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Vormwald, M. T1 - Fatigue strength and fracture mechanics N2 - If fracture mechanics shall be applied to the total lifetime respectively the fatigue limit of components (within the meaning of the S-N curve approach) it has to address four challenges: (a) It has to adequately describe so-called short crack propagation, which cannot be based on the common long crack concepts for principle reasons. Since the crack size is in the order of the plastic zone size, the modelling of short crack propagation cannot be based on the common linear elastic Delta K concept. Instead, an elastic-plastic parameter such as the cyclic J integral has to be applied. A second point is that the crack closure concept has to be modified in that the crack opening stress is not a constant, crack size- independent parameter but shows a transient behaviour with increasing short crack size. (b) It has to provide a meaningful definition of the initial crack dimensions as the starting point for an S-N curve relevant (residual) lifetime analysis. This can be based either on the (statistical) size of material defects which can be treated as cracks or by the size of the crack which would arrest subsequent to early crack propagation, whatever is larger. (c) It has to cope with the problem of multiple cracks for load levels higher than the fatigue limit such as it occurs in many applications in the absence of very large initial defects. (d) This requires consequent statistical treatment taking into account variations in the local geometry of the area where crack initiation has to be expected as well as the scatter in the initial crack size and in the material data used for the analyses. T2 - 2nd International Conference on Structural Integrity CY - Funchal, Madeira, Portugal DA - 04.09.2017 KW - Fatigue strength KW - Fracture mechanics KW - Initial crack size KW - Short crack propagation KW - Multiple crack propagation PY - 2017 DO - https://doi.org/10.1016/j.prostr.2017.07.065 SN - 2452-3216 VL - 5 SP - 745 EP - 752 AN - OPUS4-42545 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Madia, Mauro A1 - Beier, H. Th. T1 - Fatigue strength and life determination of weldments based on fracture mechanics N2 - The paper provides an overview on the results of a German cluster project on the use of fracture mechanics to the determination of the fatigue strength of weldments with fatigue cracks originating at the weld toes. The approach includes (a) a concept for short crack propagation for which the common ΔK concept is not applicable and the crack closure effects are still being gradually build-up, (b) a method for determining fatigue life relevant initial crack sizes as they are needed in any fracture mechanics analysis and (c) multiple cracking and crack coalescence at load levels higher than the endurance limit. The analyses are stochastically performed. Both, the endurance limit and the finite life branch of the S-N curve are determined. Besides a brief introduction into the approach, validation examples are presented. These comprise different weldment types (butt welds, cross joints and longitudinal stiffened plates), two steels (S355NL and S960QL) of quite different strengths, different weld geometries due to different welding techniques (WIG, MAG), as-welded and stress relieved welds and different stress ratios varying from R = -1 to R = 0.5. T2 - FDMD 2017 CY - Lecco, Italy DA - 19.09.2017 KW - Weldments KW - Fatigue strength KW - Fracture mechanics KW - Initial crack size KW - Short crack propagation KW - Multiple crack propagation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438500 DO - https://doi.org/10.1016/j.prostr.2017.11.106 SN - 2452-3216 VL - 7 SP - 407 EP - 414 PB - ScienceDirect CY - Lecco, Italy AN - OPUS4-43850 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lehmann, Jens A1 - Leonhard, H. T1 - Fehlstellen im Visier - KorroPads N2 - Rohrsysteme und Behälter aus nichtrostendem Stahl sind mit einer Passivschicht vor Korrosion geschützt. Ist diese jedoch unvollständig ausgebildet oder beschädigt, geht der Schutz verloren. Das KorroPad-Verfahren ist ein Schnelltest zur Überprüfung der Passivschicht. Im Vergleich mit bisher üblichen Bewertungsmethoden ist die Anwendung sehr einfach und nimmt nur 15 Minuten in Anspruch. KW - Nichtrostender Stahl KW - Korrosionsschnelltest KW - KorroPad KW - Passivschicht PY - 2017 SN - 0946-2856 VL - 24 IS - 11/12 SP - 66 EP - 67 PB - Vogel Business Media GmbH & Co. KG CY - Würzburg AN - OPUS4-43184 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heitz, J. A1 - Plamadeala, C. A1 - Muck, M. A1 - Armbruster, O. A1 - Baumgartner, W. A1 - Weth, A. A1 - Steinwender, C. A1 - Plessberger, H. A1 - Kellermair, J. A1 - Kirner, Sabrina V. A1 - Krüger, Jörg A1 - Bonse, Jörn A1 - Guntner, A. S. A1 - Hassel, A. W. T1 - Femtosecond laser-induced microstructures on Ti substrates for reduced cell adhesion N2 - Miniaturized pacemakers with a surface consisting of a Ti alloy may have to be removed after several years from their implantation site in the heart and shall, therefore, not be completely overgrown by cells or tissue. A method to avoid this may be to create at the surface by laser-ablation self-organized sharp conical spikes, which provide too little surface for cells (i.e., fibroblasts) to grow on. For this purpose, Ti-alloy substrates were irradiated in the air by 790 nm Ti:sapphire femtosecond laser pulses at fluences above the ablation threshold. The laser irradiation resulted in pronounced microstructure formation with hierarchical surface morphologies. Murine fibroblasts were seeded onto the laser-patterned surface and the coverage by cells was evaluated after 3–21 days of cultivation by means of scanning electron microscopy. Compared to flat surfaces, the cell density on the microstructures was significantly lower, the coverage was incomplete, and the cells had a clearly different morphology. The best results regarding suppression of cell growth were obtained on spike structures which were additionally electrochemically oxidized under acidic conditions. Cell cultivation with additional shear stress could reduce further the number of adherent cells. KW - Laser Processing KW - Femtosecond laser KW - Titanium alloy KW - Cell adhesion KW - Anodic oxidation KW - Pacemaker PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-427681 UR - https://link.springer.com/article/10.1007/s00339-017-1352-0 DO - https://doi.org/10.1007/s00339-017-1352-0 SN - 0947-8396 SN - 1432-0630 VL - 123 IS - 12 SP - 734, 1 EP - 9 PB - Springer-Verlag CY - Berlin AN - OPUS4-42768 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bonse, Jörn A1 - Kirner, Sabrina A1 - Koter, Robert A1 - Pentzien, Simone A1 - Spaltmann, Dirk A1 - Krüger, Jörg T1 - Femtosecond laser-induced periodic surface structures on titanium nitride coatings for tribological applications N2 - Titanium nitride (TiN) was coated on different substrate materials, namely pure titanium (Ti), titanium alloy (Ti6Al4V) and steel (100Cr6), generating 2.5 μm thick TiN layers. Using femtosecond laser pulses (30 fs, 790 nm, 1 kHz pulse repetition rate), large surface areas (5 mm × 5 mm) of laser-induced periodic surface structures (LIPSS) with sub-wavelength periods ranging between 470 nm and 600 nm were generated and characterized by optical microscopy (OM), white light interference microscopy (WLIM) and scanning electron microscopy (SEM). In tribological tests, coefficients of friction (COF) of the nanostructured surfaces were determined under reciprocating sliding conditions (1 Hz, 1.0 N normal load) against a 10-mm diameter ball of hardened 100Cr6 steel during 1000 cycles using two different lubricants, namely paraffin oil and engine oil. It turned out that the substrate material, the laser fluence and the lubricant are crucial for the tribological performance. However, friction and wear could not be significantly reduced by LIPSS on TiN layers in comparison to unstructured TiN surfaces. Finally, the resulting wear tracks on the nanostructured surfaces were investigated with respect to their morphology (OM, SEM), depth (WLIM) and chemical composition by energy dispersive X-ray spectroscopy (EDX) and, on one hand, compared with each other, on the other hand, with non-structured TiN surfaces. KW - Laser-induced periodic surface structures (LIPSS) KW - Femtosecond laser ablation KW - Titanium nitride films KW - Friction KW - Wear PY - 2017 UR - http://www.sciencedirect.com/science/article/pii/S0169433216322486 DO - https://doi.org/10.1016/j.apsusc.2016.10.132 SN - 0169-4332 SN - 1873-5584 VL - 418 IS - Part B SP - 572 EP - 579 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-40507 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schröder, Volkmar A1 - Molnarne, Maria T1 - Flammability of gases in focus of European and US standards N2 - The presentation will discuss the difference between EU and US standards for the determination of explosion (flammability) limits and limiting oxygen concentration. Small differences observed in measured values can be traced back to the different test apparatuses and criteria. The discrepancies can be much greater in the case of limiting oxygen concentration because of the high amount of inert gases and the corresponding low laminar burning velocities. The paper describes some examples and the influence of the chosen criteria on the results. The European and US standards use the criteria of flame propagation in open test vessels and of pressure rise in closed ones. The examples discussed show that flame propagation is still possible at very small pressure rise values, as observed much below the pressure rise criterion of usual standards. However, flame propagation in a process plant can cause an accident or explosion and must be avoided. Therefore, the flame propagation criterion is recommended to be used in chemical safety engineering. The European safety database CHEMSAFE contains expertevaluated safety data for cases where the determination method and criteria are known. Flammability characteristics based on the pressure rise criterion may suffice in certain cases, e.g. for explosion protection in closed vessels without any connecting pipes. KW - Flammability KW - Limiting oxygen concentration KW - Test methods KW - Standards PY - 2017 DO - https://doi.org/10.1016/j.jlp.2017.05.012 SN - 0950-4230 SN - 1873-3352 VL - 48 SP - 297 EP - 304 PB - Elsevier CY - Amsterdam AN - OPUS4-40980 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Cappella, Brunero T1 - Force-distance curves on lubricant films: An approach to the characterization of the shape of the AFM tip N2 - Force-distance curves have been acquired with an atomic force microscope on perfluorpolyether films. It is shown that curves acquired on films of different thickness, at different rates and with different dwell times can be overlapped by rescaling the time or distance axis.When the time or distance axis is rescaled,the force depends only on the surface tension of perfluorpolyether and on geometrical properties of thetip (aperture and perimeter of the tip at a given distance from the apex). Hence, curves acquired with thesame tip overlap. By comparing curves acquired at different rates the dynamics of tip-wetting can be investigated. Fur-thermore, rescaled force-distance curves have been matched with the perimeter of cross sections ofthe tip, i.e. with the perimeter of the three-phase contact line. Such measurements pave the way for anon-destructive investigation of the tip shape. KW - Lubricant films KW - Surface tension KW - Atomic force microscopy KW - Force-distance curves KW - AFM tip shape PY - 2017 DO - https://doi.org/10.1016/j.micron.2016.11.006 SN - 0968-4328 VL - 93 SP - 20 EP - 28 AN - OPUS4-38391 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Olejko, Lydia A1 - Bald, Ilko T1 - FRET efficiency and antenna effect in multi-color DNA origami-based light harvesting systems N2 - Artificial light harvesting complexes find applications in artificial photosynthesis, photovoltaics and light harvesting chemical sensors. They are used to enhance the absorption of light of a reaction center which is often represented by a single acceptor. Here, we present different light harvesting systems on DNA origami structures and analyze systematically the light harvesting efficiency. By changing the number and arrangement of different fluorophores (FAM as donor, Cy3 as transmitter and Cy5 as acceptor molecules) the light harvesting efficiency is optimized to create a broadband absorption and to improve the antenna effect 1 (including two energy transfer steps) from 0.02 to 1.58, and the antenna effect 2 (including a single energy transfer step) from 0.04 to 8.7, i.e. the fluorescence emission of the acceptor is significantly higher when the light-harvesting antenna is excited at lower wavelength compared to direct excitation of the acceptor. The channeling of photo energy to the acceptor proceeds by Förster Resonance Energy Transfer (FRET) and we carefully analyze also the FRET efficiency of the different light harvesting systems. Accordingly, the antenna effect can be tuned by modifying the stoichiometry of donor, transmitter and acceptor dyes, whereas the FRET efficiency is mainly governed by the spectroscopic properties of dyes and their distances. KW - DNA origami KW - Light-harvesting KW - FRET KW - Antenna effect PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-405867 UR - http://pubs.rsc.org/en/content/articlelanding/2017/ra/c7ra02114c#!divAbstract DO - https://doi.org/10.1039/C7RA02114C VL - 7 IS - 39 SP - 23924 EP - 23934 PB - The Royal Soc. of Chemistry AN - OPUS4-40586 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schilling, Markus A1 - Niebergall, Ute A1 - Böhning, Martin T1 - Full notch creep test (FNCT) of PE-HD – Characterization and differentiation of brittle and ductile fracture behavior during environmental stress cracking (ESC) N2 - The damage mechanisms slow crack growth (SCG) and environmental stress cracking (ESC), relevant for PE-HD materials are characterized based on improved full notch creep testing (FNCT) of two selected typical PE-HD materials for container applications. In this context, a distinction of the failure mechanisms as well as a categorization of involved media is suggested. Employing a novel FNCT device, elongation data were obtained in addition to conventional time-to-failure results of stress-dependent as well as temperature-dependent measurements. Changes in failure behavior, as determined by fracture surface analysis based on light microscopy (LM) and laser scanning microscopy (LSM), are correlated with FNCT results and used to introduce an additional possibility for the identification of brittle/ductile fracture behavior. KW - Environmental stress cracking (ESC) KW - Slow crack growth (SCG) KW - Full notch creep test (FNCT) KW - High-density polyethylene (PE-HD) PY - 2017 DO - https://doi.org/10.1016/j.polymertesting.2017.09.043 SN - 0142-9418 SN - 1873-2348 VL - 64 SP - 156 EP - 166 PB - Elsevier CY - Amsterdam AN - OPUS4-42484 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Gleitverhalten von PEEK-Kompositwerkstoffen in Wasserstoffumgebung N2 - Die Reibeigenschaften von PEEK Materialien gegen Stahlscheiben wurden in Luft, Vakuum und Wasserstoffumgebung untersucht. KW - PEEK-Komposite KW - Wasserstoff KW - Vakuum KW - Graphit PY - 2017 SN - 0724-3472 VL - 64 IS - 6 SP - 52 EP - 59 AN - OPUS4-42919 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heck, Christian A1 - Prinz, Julia A1 - Dathe, A. A1 - Merck, V. A1 - Stranik, O. A1 - Fritzsche, W. A1 - Kneipp, Janina A1 - Bald, Ilko T1 - Gold nanolenses self-assembled by DNA origami N2 - Nanolenses are self-similar chains of metal nanoparticles, which can theoretically provide extremely high field enhancements. Yet, the complex structure renders their synthesis challenging and has hampered closer analyses so far. Here, DNA origami is used to self-assemble 10, 20, and 60 nm gold nanoparticles as plasmonic gold nanolenses (AuNLs) in solution and in billions of copies. Three different geometrical arrangements are assembled, and for each of the three designs, surface-enhanced Raman scattering (SERS) capabilities of single AuNLs are assessed. For the design which shows the best properties, SERS signals from the two different internal gaps are compared by selectively placing probe dyes. The highest Raman enhancement is found for the gap between the small and medium nanoparticle, which is indicative of a cascaded field enhancement. KW - DNA origami KW - SERS KW - Gold nanoparticles KW - Plasmonics PY - 2017 UR - http://pubs.acs.org/doi/pdf/10.1021/acsphotonics.6b00946 DO - https://doi.org/10.1021/acsphotonics.6b00946 SN - 2330-4022 VL - 4 IS - 5 SP - 1123 EP - 1130 AN - OPUS4-40587 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Chandra, K. A1 - Kranzmann, Axel T1 - High temperature oxidation of 9–12% Cr ferritic/martensitic steels under dual-environment conditions N2 - In normal operations, the opposite surfaces of the power plant components are exposed to two different environments, i.e. air/flue gas on the one side and steam on the other side. Exposure under such dual-environment can lead to accelerated corrosion of the components on the air side. The oxidation behaviour of ferritic/martensitic steel T92 was investigated under dual-environment in a specially designed test equipment. The samples were exposed to dry oxyfuel flue gas (CO2–27%N2–2%O2–1%SO2) on one side and to steam on the other side up to 1000 h at 650°C. The formation of oxide scales was characterised by optical microscopy and scanning electron microscopy with attached energy-dispersive spectroscopy. Oxidation rate of specimens under dual-Environment condition was almost three times higher than that in single-environment condition. This is explained based on hydrogen transport through the bulk alloy from the steam side to the flue gas side. KW - Oxidation KW - Dual-environment KW - Oxyfuel KW - Ferritic/martensitic steel KW - Steam PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-457101 DO - https://doi.org/10.1080/1478422X.2017.1374049 VL - 53 IS - 31 SP - 27 EP - 33 PB - Taylor & Francis AN - OPUS4-45710 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Gook, S. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Hybrid laser arc welding of high grade X80 and X120 pipeline steels N2 - The aim of the present work was to investigate the possibilities of hybrid laser arc welding regarding reliable production of longitudinal welds of high strength pipe steels X80 and X120 and to evaluate achievable mechanical properties of laser hybrid welds. The study focused on weld toughness examination in low temperature range up to -60 °C. SЮТЭКЛХО ПТХХОЫ ЦКЭОЫТКХЬ were identified in the context of this task. It could be shown that metal cored electrodes guaranteed sufficient Charpy impact toughness at low temperature for both investigated materials. Modern arc welding technologies such as modified pulsed spray arc were used to promote deeper Penetration of the filler material into the narrow laser welding gap. Edge preparation with a 14 mm deep root face was considered as optimum, because no penetration of the filler material could be detected beyond this depth limit and therefore any metallurgical influences on the weld metal properties through the welding wire could be excluded. KW - High strength steel KW - Longitudinal weld KW - Modified spray arc KW - Pipeline KW - Hybrid laser arc welding PY - 2017 SN - 2499-9733 SN - 2305-414Х VL - 1 IS - 22 SP - 21 EP - 35 AN - OPUS4-44343 LA - rus AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zhang, Rui A1 - Russo, Patrícia A. A1 - de Oliveira Guilherme Buzanich, Ana A1 - Jeon, Taeyeol A1 - Pinna, Nicola T1 - Hybrid organic–inorganic transition-metal phosphonates as precursors for water oxidation electrocatalysts N2 - Efficient water oxidation catalysts are required for the development of water splitting technologies. Herein, the synthesis of layered hybrid NiFephenylphosphonate compounds from metal acetylacetonate precursors and phenylphosphonic acid in benzyl alcohol, and their Oxygen evolution reaction performance in alkaline medium, are reported. The hybrid particles are formed by inorganic layers of NiO6 and FeO6 distorted octahedra separated by bilayers of the organic group, and template the Formation in situ of NiFe hydroxide nanosheets of sizes between 5 and 25 nm and thicknesses between 3 and 10 nm. X-ray absorption spectroscopy measurements suggest that the hybrid also acts as a template for the local structure of the metal sites in the active catalyst, which remain distorted after the transformation. Optimum electrocatalytic activity is achieved with the hybrid compound with a Fe content of 16%. The combination of the synergistic effect between Ni and Fe with the structural properties of the hybrid results in an efficient catalyst that generates a current density of 10 mA cm−2 at an overpotential of 240 mV, and also in a stable catalyst that operates continuously at low overpotentials for 160 h. KW - Water oxydation catalysis KW - EXAFS PY - 2017 DO - https://doi.org/10.1002/adfm.201703158 SN - 1616-301X SN - 1616-3028 VL - 27 IS - 40 SP - Article 1703158, 1 EP - 11 PB - WILEY-VCH Verlag CY - Weinheim AN - OPUS4-42783 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Silverstein, R. A1 - Sobol, Oded A1 - Böllinghaus, Thomas A1 - Unger, Wolfgang A1 - Eliezer, D. T1 - Hydrogen behavior in SAF 2205 duplex stainless steel N2 - This paper describes austenitic-ferritic duplex stainless steels, SAF 2205, in the presence of hydrogen. The duplex stainless steels (DSS) properties include excellent resistance to stress corrosion cracking, high strength and good weldability. Those steels are preferably used in industries combining hydrogen and loads. Hydrogen location in addition to hydrogen binding energy with the steel's defects are of great importance for the analysis of hydrogen embrittlement model in that steel. It is known from previously published works that the susceptibility to hydrogen embrittlement will depend on the competition between reversible and irreversible traps; meaning a direct relation to the hydrogen's state and position in the steel. In this work, we examine the local hydrogen concentration, trapping and distribution by two modern and advanced techniques: thermal desorption spectrometry (TDS) and we support it by time of flight-secondary ion mass spectrometer (ToF-SIMS). In this paper, we support and give for the first time new insights and better understanding to the hydrogen embrittlement mechanism in SAF 2205. The trapping energies levels were calculated using TDS and Lee and Lee's model. This model revealed reversible in addition to irreversible trapping sites. Also the trapping controlling mechanism was found to be a combination of detrapping controlled mechanism and diffusion controlled mechanism. The use of ToF-SIMS for local imaging the distribution of hydrogen species supports the discussion of the different hydrogen traps in this type of steel. The hydrogen embrittlemet phenomenon in SAF 2205 will be discussed in details in that paper. KW - Hydrogen trapping KW - Duplex stainless steel KW - Thermal desorption spectrometry (TDS) KW - ToF-SIMS PY - 2017 DO - https://doi.org/10.1016/j.jallcom.2016.11.184 SN - 0925-8388 SN - 1873-4669 VL - 695 SP - 2689 EP - 2695 PB - Elsevier B.V. AN - OPUS4-38856 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Omara, Shereen Shabaan A1 - Turky, G. A1 - Ghoneim, A. A1 - Thünemann, Andreas A1 - Abdel Rehim, M. H. A1 - Schönhals, Andreas T1 - Hyperbranched poly(amidoamine)/kaolinite nanocomposites: Structure and charge carrier dynamics N2 - An ex-situ approach was applied to prepare nanocomposites from hyperbranched poly(amidoamine) and modified kaolinite (Ka-DCA). The structure of the polymer and the corresponding nanocomposites was investigated by FTIR, DSC, SAXS and TEM. SAXS might suggest a partly exfoliated structure of the nanocomposites, which was supported by TEM. The molecular dynamics was studied by means of broadband dielectric spectroscopy (BDS). The dielectric spectra are dominated by a conductivity contribution at higher temperatures for all samples investigated. The obtained results further indicated that DC conductivity is increased by 4 orders of magnitude with increasing concentration of Ka-DCA nanofiller. Further, a significant separation between the conductivity relaxation time and that of segmental dynamics was observed. The decoupling phenomenon and the conductivity mechanism were discussed in detail. This study provides insights about the influence of the nanofiller on the structure and the conductivity contribution of nanocomposites of hyperbranched polymers including the decoupling phenomenon and fragility. KW - Hyperbranched polymers KW - Nanocomposites KW - Conductivity PY - 2017 DO - https://doi.org/10.1016/j.polymer.2017.06.017 SN - 0032-3861 VL - 121 SP - 64 EP - 74 PB - Elsevier Ltd. AN - OPUS4-40648 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sieg, H. A1 - Kästner, Claudia A1 - Krause, B. A1 - Meyer, T. A1 - Burel, A. A1 - Böhmert, L. A1 - Lichtenstein, D. A1 - Jungnickel, H. A1 - Tentschert, J. A1 - Laux, P. A1 - Braeuning, A. A1 - Estreal-Lopis, I. A1 - Gauffre, F. A1 - Fessard, V. A1 - Meijer, J. A1 - Luch, A. A1 - Thünemann, Andreas A1 - Lampen, A. T1 - Impact of an artificial digestion procedure on aluminum-containing nanomaterials N2 - Aluminum has gathered toxicological Attention based on relevant human exposure and its suspected hazardous potential. Nanoparticles from food supplements or Food contact materials may reach the human gastrointestinal tract. Here, we monitored the physicochemical fate of aluminum containing nanoparticles and aluminum ions when passaging an in vitro model of the human gastrointestinal tract. Smallangle X-ray scattering (SAXS), transmission electron microscopy (TEM), ion beam microscopy (IBM), secondary ion beam mass spectrometry (TOF-SIMS), and inductively coupled plasma mass spectrometry (ICP-MS) in the singleparticle mode were employed to characterize two aluminumcontaining nanomaterials with different particle core materials (Al0, γAl2O3) and soluble AlCl3. Particle size and shape remained unchanged in saliva, whereas strong Agglomeration of both aluminum nanoparticle species was observed at low pH in gastric fluid together with an increased ion release. The levels of free aluminum ions decreased in intestinal fluid and the particles deagglomerated, thus liberating primary particles again. Dissolution of nanoparticles was limited and substantial changes of their shape and size were not detected. The amounts of particle-associated phosphorus, chlorine, potassium, and calcium increased in intestinal fluid, as compared to nanoparticles in standard dispersion. Interestingly, nanoparticles were found in the intestinal fluid after addition of ionic aluminum. We provide a comprehensive characterization of the fate of aluminum nanoparticles in simulated gastrointestinal fluids, demonstrating that orally ingested nanoparticles probably reach the intestinal epithelium. The balance between dissolution and de novo complex formation should be considered when evaluating nanotoxicological experiments. KW - Small-angle X-ray scattering KW - SAXS KW - Nanoparticle PY - 2017 DO - https://doi.org/10.1021/acs.langmuir.7b02729 SN - 1520-5827 SN - 0743-7463 VL - 33 IS - 40 SP - 10726 EP - 10735 PB - Americal Chemical Society AN - OPUS4-42438 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -