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 JF - Physical Chemistry Chemical Physics 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 - Liehr, Sascha A1 - Muanenda, Y. S. A1 - Münzenberger, Sven A1 - Krebber, Katerina T1 - Relative change measurement of physical quantities using dual-wavelength coherent OTDR JF - Optics Express 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 - CHAP A1 - Sproesser, G. A1 - Change, Y.-J. A1 - Pittner, Andreas A1 - Finkbeiner, M. A1 - Rethmeier, Michael ED - Stark, R. ED - Bonvoisin, J. ED - Seliger, G. T1 - Sustainable technologies for thick metal plate welding T2 - Sustainable Manufacturing Challenges, Solutions and Implementation Perspectives N2 - Welding is the most important joining technology. In the steel construction industry, e.g. production of windmill sections, welding accounts for a main part of the manufacturing costs and resource consumption. Moreover, social issues attached to welding involve working in dangerous environments. This aspect has unfortunately been neglected so far, in light of a predominant focus on economics combined with a lack of suitable assessment methods. In this chapter, exemplary welding processes are presented that reduce the environmental and social impacts of thick metal plate welding. Social and environmental Life Cycle Assessments for a thick metal plate joint are conducted for the purpose of expressing and analysing the social and environmental impacts of welding. Furthermore, it is shown that state-of-the-art technologies like Gas Metal Arc Welding with modified spray arcs and Laser Arc-Hybrid Welding serve to increase social and environmental performance in contrast to common technologies, and therefore offer great potential for sustainable manufacturing. KW - Human health G. KW - Life cycle assessment (LCA) KW - Arc welding KW - Laser arc-hybrid welding KW - Resource efficiency KW - Social life cycle assessment (SLCA) PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-390025 SN - 978-3-319-48513-3 SN - 978-3-319-48514-0 DO - https://doi.org/10.1007/978-3-319-48514-0 SN - 2194-0541 SN - 2194-055X SP - 71 EP - 84 PB - Springer CY - Cham, Switzerland AN - OPUS4-39002 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kromm, Arne A1 - Rhode, Michael A1 - Launert, B. A1 - Dixneit, Jonny A1 - Kannengießer, Thomas A1 - Pasternak, H. ED - Olden, T.-M. ED - Muransky, O. ED - Edwards, L. T1 - Combining sectioning method and X-ray diffraction for evaluation of residual stresses in welded high strength steel components T2 - Residual Stresses 2016: ICRS-10 N2 - Residual stresses and distortions in welded I-girders for steel construction are relevant when evaluating the stability of steel beams and column members. The application of high strength steels allows smaller wall thicknesses compared to conventional steels. Therefore, the risk of buckling has to be considered carefully. Due to the lack of knowledge concerning the residual stresses present after welding in high strength steel components conservative assumptions of their level and distribution is typically applied. In this study I-girders made of steels showing strengths of 355 MPa and 690 MPa were welded with varying heat input. Due to the dimension of the I-girders and the complex geometry the accessibility for residual stress measurement using X-ray diffraction was limited. Therefore, saw cutting accompanied by strain gauge measurement has been used to produce smaller sections appropriate to apply X-ray diffraction. The stress relaxation measured by strain gauges has been added to residual stresses determined by X-ray diffraction to obtain the original stress level and distribution before sectioning. The combination of both techniques can produce robust residual stress values. From practical point of view afford for strain gauge application can be limited to a number of measuring positions solely to record the global amount of stress relaxation. X-ray diffraction can be applied after sectioning to determine the residual stresses with sufficient spatial resolution. T2 - ICRS 2016 - 10th International Conference on Residual Stresses CY - Sydney, Australia DA - 03.07.2016 KW - Welding KW - Residual Stress KW - Sectioning Method KW - X-Ray Diffraction KW - Component Testing PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-389206 SN - 978-1-94529117-3 SN - 978-1-94529117-6 DO - https://doi.org/10.21741/9781945291173-28 SN - 2474-395X VL - 2 SP - 163 EP - 168 PB - Materials Research Forum LLC CY - Millersville (PA), USA AN - OPUS4-38920 LA - eng 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 JF - PLoS ONE 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 - JOUR A1 - Wohlleben, W. A1 - Mielke, Johannes A1 - Bianchin, A. A1 - Ghanem, A. A1 - Freiberger, H. A1 - Rauscher, H. A1 - Gemeinert, Marion A1 - Hodoroaba, Vasile-Dan T1 - Reliable nanomaterial classification of powders using the volume-specific surface area method JF - Journal of Nanoparticle Research N2 - The volume-specific surface area (VSSA) of a particulate material is one of two apparently very different metrics recommended by the European Commission for a definition of "nanomaterial" for regulatory purposes: specifically, the VSSA metric may classify nanomaterials and non-nanomaterials differently than the median size in number metrics, depending on the chemical composition, size, polydispersity, shape, porosity, and aggregation of the particles in the powder. Here we evaluate the extent of agreement between classification by electron microscopy (EM) and classification by VSSA on a large set of diverse particulate substances that represent all the anticipated challenges except mixtures of different substances. EM and VSSA are determined in multiple labs to assess also the level of reproducibility. Based on the results obtained on highly characterized benchmark materials from the NanoDefine EU FP7 project, we derive a tiered screening strategy for the purpose of implementing the definition of nanomaterials. We finally apply the Screening strategy to further industrial materials, which were classified correctly and left only borderline cases for EM. On platelet-shaped nanomaterials, VSSA is essential to prevent false-negative classification by EM. On porous materials, approaches involving extended Adsorption isotherms prevent false positive classification by VSSA. We find no false negatives by VSSA, neither in Tier 1 nor in Tier 2, despite real-world industrial polydispersity and diverse composition, shape, and coatings. The VSSA screening strategy is recommended for inclusion in a technical guidance for the implementation of the definition. KW - Nanomaterial KW - Nanomaterial classification KW - Regulation KW - VSSA KW - Size measurement KW - Particle size PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-391450 DO - https://doi.org/10.1007/s11051-017-3741-x SN - 1388-0764 SN - 1572-896X VL - 19 IS - 2 SP - Article 61, 1 EP - 16 PB - Springer Nature AN - OPUS4-39145 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Madia, Mauro A1 - Schork, B. A1 - Bernhard, J. A1 - Kaffenberger, M. T1 - Multiple crack initiation and propagation in weldments under fatigue loading JF - 3rd International symposium on fatigue design and material defects (FDMD 2017) N2 - The work aims at addressing the modelling and implementation of criteria for multiple crack propagation, including interaction and coalescence, for a more reliable fracture mechanics-based prediction of stress-life curves for weldments. A large experimental work is presented in which micro-cracks have been made visible by heat-tinting at successive stages of fatigue life of the welded specimens. Here the correlation between the number of initiation sites and the applied stress level has been also investigated. The criteria have been implemented in in-house software, which allows multiple fatigue crack propagation, and validated against selected experimental tests. The results have shown that the modelling of multiple crack propagation and interaction is crucial for the prediction of the fatigue strength of weldments, both in finite and infinite life regime. T2 - FDMD 2017 CY - Lecco, Italy DA - 19.09.2017 KW - Weldments KW - Fatigue strength KW - Multiple crack propagation PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438593 DO - https://doi.org/10.1016/j.prostr.2017.11.108 SN - 2452-3216 VL - 7 SP - 423 EP - 430 PB - Elsevier B.V. AN - OPUS4-43859 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nikolic, Nela A1 - Dal Co, Alma A1 - Kiviet, Daniel J. A1 - Bergmiller, Tobias A1 - Littmann, Sten A1 - Kuypers, Marcel M. M. A1 - Ackermann, Martin A1 - Schreiber, Frank T1 - Cell-to-cell variation and specialization in sugar metabolism in clonal bacterial populations JF - PLoS Genetics N2 - While we have good understanding of bacterial metabolism at the population level, we know little about the metabolic behavior of individual cells: do single cells in clonal populations sometimes specialize on different metabolic pathways? Such metabolic specialization could be driven by stochastic gene expression and could provide individual cells with growth benefits of specialization. We measured the degree of phenotypic specialization in two parallel metabolic pathways, the assimilation of glucose and arabinose. We grew Escherichia coli in chemostats, and used isotope-labeled sugars in combination with nanometer-scale secondary ion mass spectrometry and mathematical modeling to quantify sugar assimilation at the single-cell level. We found large variation in metabolic activities between single cells, both in absolute assimilation and in the degree to which individual cells specialize in the assimilation of different sugars. Analysis of transcriptional reporters indicated that this variation was at least partially based on cell-to-cell variation in gene expression. Metabolic differences between cells in clonal populations could potentially reduce metabolic incompatibilities between different pathways, and increase the rate at which parallel reactions can be performed. KW - Metabolism KW - Escherichia coli KW - Phenotypic diversity KW - Phenotypic heterogeneity PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-438873 UR - http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1007122 DO - https://doi.org/10.1371/journal.pgen.1007122 SN - 1553-7404 VL - 13 IS - 12 SP - e1007122, 1 EP - e1007122, 24 PB - Public Library of Science CY - Cambridge, United Kingdom AN - OPUS4-43887 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wolf, Marcus A1 - Afanasiev, Roman A1 - Böllinghaus, Thomas A1 - Pfennig, A. T1 - Investigation of Corrosion Fatigue of Duplex Steel X2CrNiMoN22-5 3 Exposed to a Geothermal Environment under Different Electrochemical Conditions and Load Types JF - Energy Procedia N2 - Corrosion fatigue (CF) of duplex stainless steel (DSS) X2CrNiMoN22-5-3 was investigated in in-situ geothermal conditions of the Northern German Basin (NGB). The influence of the load type on CF behavior of the alloy was examined by applying push/pull and rotating bending cyclic load to failure. The hour-glass shaped specimens with both polished and precisely turned surface finish were tested in corrosion chambers allowing for the permanent circulation of Northern German Basin electrolyte heated to 369 K. Additionally, the influence of a protective cathodic potential on the CF life expectancy was investigated by employing a potentiostat. The rotating bending cyclic load led to a higher CF life expectancy, which decreased with increasing duration of the experiment due to a higher deterioration rate of the material. The application of a cathodic potential caused a significant increase of the CF lifespan from 4.7 x 105 (open-circuit potential (OCP)) to 107 cycles (preset threshold cycle number) for the potential range from USHE = – 450 to – 900 mV. Microstructural analysis of the CF damage revealed horizontal grain attack within corrosion pit cavities, multiple fatigue cracks and preferable deterioration of the austenitic phase. T2 - 13th International Conference on Greenhouse Gas Control Technologies, GHGT-13 CY - Lausanne, Switzerland DA - 14.11.2016 KW - Different load cases KW - Corrosion fatigue KW - DSS KW - Geothermal environment KW - Different electrochemical conditions PY - 2017 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-439231 DO - https://doi.org/10.1016/j.egypro.2017.03.1657 SN - 1876-6102 VL - 114 SP - 5337 EP - 5345 PB - Elsevier Science AN - OPUS4-43923 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 JF - 3rd international Symposium on fatigue design and material defects (FDMD 2017) 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 -