TY - JOUR A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Influence of gamma irradiation on low temperature properties of rubber seal materials N2 - In many fields the function of seal materials is required at low temperatures. Therefore the understanding of failure mechanisms at low temperatures is of high importance. In some applications elastomeric seals are used in environments with increased irradiation backgrounds, as e.g. in containers for radioactive waste. This paper reports on the influence of gamma irradiation on the low temperature properties of different fluorocarbon rubber (FKM) materials. The samples were irradiated with gamma doses of up to 600 kGy and the induced changes of material properties were tested by methods sensitive to the rubber-glass transition, like DSC and DMA. Additionally, compression set measurements were performed to give information about recovery behaviour at low temperatures. KW - Seal KW - O-ring KW - Low temperature KW - Gamma irradiation KW - Compression set KW - Dichtungen KW - O-Ringe KW - Tiefe Temperatur KW - Gamma-Bestrahlung KW - Druckverformungsrest PY - 2015 SN - 0948-3276 SN - 0022-9520 VL - 68 IS - 6 SP - 85 EP - 89 PB - Hüthig CY - Heidelberg AN - OPUS4-33552 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Friction and wear behaviour of graphite filled polymer composites in hydrogen environment N2 - High performance polymer composites have been intensively investigated for tribological applications in air, but rarely in hydrogen environment. Author's previous benchmark of composites in liquid hydrogen (LH2) showed that graphite filled polymers have beneficial friction behaviour in this extreme condition. Therefore, further investigations have been undertaken in hydrogen environment. This paper presents first results obtained with polyimide composites filled with different types (natural, synthetic) and amounts of graphite in air, vacuum and hydrogen environments. A particular attention is taken to the influence of hydrogen on graphite as well as on the polymer matrix. KW - Polymer composites KW - Polyimide KW - Graphite KW - Friction KW - Wear KW - Hydrogen environment KW - Vacuum PY - 2015 DO - https://doi.org/10.2474/trol.10.207 SN - 1881-2198 VL - 10 IS - 2 SP - 207 EP - 212 CY - Tokyo, Japan AN - OPUS4-33554 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Tribological characteristics of polyimide composites in hydrogen environment N2 - The influence of hydrogen environment on the friction and wear behavior of polyimide (PI) composites was investigated for two different PI-types (PI1 and PI2) filled with natural or synthetic graphite. Sliding tests were run against AISI 52100 steel and the worn surfaces as well as the transfer film were analyzed by means of SEM, EDX and Infrared Spectroscopy. Results indicate that the chemical structure of the polyimide has a major influence on the tribological behavior. While the friction of PI2 remains rather stable in all environments, PI1 showed very low friction in hydrogen without any lubricant. The lubricity of graphite was found to be more effective in hydrogen than in moist air. KW - Sliding friction KW - Polyimide KW - Graphite KW - Hydrogen PY - 2015 DO - https://doi.org/10.1016/j.triboint.2015.06.001 SN - 0301-679X VL - 92 SP - 162 EP - 171 PB - Elsevier Ltd. CY - Oxford AN - OPUS4-33555 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Burbank, John Theodore A1 - Woydt, Mathias T1 - Friction and wear reductions under slip-rolling contact through chemically reactive tribofilm generation during pre-conditioning of steel alloys N2 - The running-in phase of mechanical systems is critical from a tribological standpoint, though poorly understood. Microcracks accelerate material failure and wear during this phase of heightened friction. With this in mind, the ultimate goal of this current work is to transfer the running-in phase into the final step of the mechanical finishing process through the targeted pre-conditioning of novel, high toughness steel bearings without thermo-chemical treatments and compare these to conventional, case-hardened steels. This pre-conditioning involved the targeted implementation of two specific lubricant packages, the first with CaCO3 as the active ingredient and the second with MoDTC as the active ingredient, to generate chemically reactive tribolayers (tribofilms) on twin disk testing rigs. Pre-conditioning was carried out up to 104 load cycles (approximately 25 min). The films generated in pre-conditioning were analyzed by SEM-EDX with Element-Mapping, Raman spectroscopy, and XPS to elucidate their molecular composition and concentration on the sample surfaces. The combination of these methods of analysis gave a clear indication that 104 cycles were sufficient to generate stable chemical tribofilms. CaO and CaCO3 were the main components of the tribofilm from the first lubricant package, while MoS2, MoO2 and MoO3 were the main components from the second lubricant package. Tribofilm-protected samples were then subjected to slip-rolling endurance testing (T=+120 °C, 10,000,000 cycles, approximately 19 days in a factory fill engine oil) to determine any changes in friction behavior or wear performance. Some significant reductions in coefficients of friction at the end of endurance testing were observed, though in certain cases, no definitive improvement was observed. In contrast, very strong reductions in wear were observed across the entire spectrum of materials and testing loads. In some cases, sample surface wear reduction from pre-conditioning via tribofilms reached over 90%. The observed improvements to friction behavior and wear performance are indicative of a technically simple, cost- and energy-efficient pre-conditioning method that may prove to be competitive with existing thermochemical treatments for steel alloys. KW - Tribofilm KW - Running-in KW - MoDTC KW - Slip-rolling KW - Friction KW - Wear PY - 2015 DO - https://doi.org/10.1016/j.wear.2015.06.006 SN - 0043-1648 VL - 338-339 SP - 133 EP - 143 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-33556 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geburtig, Anja T1 - A new weathering device for plastic containers with parallel impact of dangerous liquids N2 - For plastic packaging, both weathering and Chemical exposure are well known, slow-going damaging scenarios, which themselves are sufficiently covered in relevant transport regulations, but treated there separately. In previous work, it has been shown that both can act synergistically, resulting in leakage failure after only six month outdoor exposure in Berlin/Germany. A new weathering device is presented which enables combined exposure of whole components under controlled laboratory conditions. This device allows exposure of an up to 60 litres Container which is filled with dangerous liquid. By using a collecting drip pan and an extractor hood, safety is guaranteed, also in case of leakage failure. Irradiance homogeneity is realized by rotating the Container between two opposed lamp fields consisting of vertically arranged UV fluorescent lamps. Using UVA 340nm lamps with spectral emission mainly between 290 and 380 nm, the short wave ränge of global solar radiation is simulated very precisely. UV irradiance is constantly 60 W/m2, thus it is a bit higher than maximum global solar radiation in the considered UV ränge. Radiation heating is knowingly excluded, avoiding heat production that potentially could be critical for included dangerous liquids. Adjusting constant temperature of 40 °C, chosen conditions aim at worst case outdoor conditions, for uncolored Containers. T2 - 27th IAPRI Symposium on packaging CY - Valencia, Spain DA - 08.06.2015 KW - Weathering exposure KW - Chemical exposure KW - Plastic packaging PY - 2015 SN - 978-84-943398-4-4 SP - 1 EP - 5 AN - OPUS4-33488 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Wolff, Dietmar T1 - Investigation of elastomer seal behaviour for transport and storage packages N2 - According to the relevant guidelines and regulations, the safe enclosure of radioactive Container contents has to be guaranteed for long storage periods as well as down to temperatures of -40 °C during transportation. As rubbers are widely used as the main sealing materials for Containers for low- and intermediate-level radioactive waste and as additional component to metal seals in spent fuel and high active waste Containers, a comprehensive eiastomer investigation Programme is in place at BAM. This Programme comprises investigations of overall eiastomer performance, durability, influence of gamma irradiation and low temperature behaviour. In this paper we focus on the behaviour of eiastomer seals at low temperatures with regard to the potential increase in leakage as material properties of rubbers are strongly temperature-dependent. During continuous cooling, the material behaviour of elastomers changes in the rubber-glass transition temperature ränge from rubberlike entropy-elasticity to stiff energy-elasticity, allowing for almost no strain or retraction. Hence rubbers are normally used above their rubber-glass transition but the minimum limit at which they work has not been defined precisely. For the investigations, fluorocarbon (FKM) and ethylene-propylene-diene (EPDM) rubbers were selected, as they are often used in radioactive waste Containers. The elastomers were studied using several thermoanalytical methods and compression set. The results were compared with component tests to determine the temperature at which the sealing function of O-rings made of eiastomer breaks down. In addition to these results, under static conditions we designed a new measurement set-up which allows for a small deflection of the flange and simultaneous leakage rate measurement at low temperatures. T2 - RAMTRANS 2015 - 10th International conference on radioactive materials transport and storage CY - Oxford, UK DA - 19.05.2015 KW - O-ring KW - Glass-rubber transition KW - Irradiation KW - Compression set PY - 2015 SP - 1 EP - 10 AN - OPUS4-33489 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Salg, Steffen A1 - Michael-Schulz, Heike A1 - Malow, Marcus T1 - Use of a four-liter-autoclave for conducting deflagration tests N2 - For the determination of deflagration capability of energetic substances, the test methods according to VDI 2263-1, part 1.6 and UN-Manual, C.1- und C.2-test are used. These methods are suited to evaluate the intrinsic material property deflagration. For evaluation of deflagration behavior in closed systems, for example in production sites, an appropriate test apparatus is missing. Because of this, the BAM Federal Institute for Materials Research and Testing developed a four-liter-autoclave for conducting the deflagration test under isochoric conditions. Deflagration behavior was evaluated under different parameters e. g. pressure and temperature. On the basis of results it can be seen, that the four-liter-autoclave is suited for the determination of deflagration behavior. On the one hand, the same characteristics as in the standard test methods are obtained. On the other hand, there are additional characteristics, like pressure rise and decomposition velocity. On the basis of pressure measurement, the emerging gas volume and the rate of gas evolution, that are used to design protection measures, can be estimated. The measurements are conducted with the deflagrating substance Azodicarboxamide (ADCA). It is concluded that the four-liter-autoclave is a good alternative for conducting deflagration tests. T2 - 18th Seminar on new trends in research of energetic materials - NTREM CY - Pardubice, Czech Republic DA - 15.04.2015 KW - Deflagration KW - Azodicarboxamide KW - Closed vessel KW - Pressure rise KW - Arising gases PY - 2015 UR - http://www.ntrem.com/download/NTREM_2015_abstracts.pdf SN - 978-80-7395-891-6 SN - 978-80-7395-892-3 SP - 255 EP - 264 AN - OPUS4-33490 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Salg, Steffen A1 - Malow, Marcus A1 - Morhenn, H. T1 - Experimentelle und theoretische Untersuchung des Zersetzungsmechanismus deflagrationsfähiger Substanzen N2 - In einem Vier-Liter-Autoklaven wurden erstmals Untersuchungen zu Deflagrationen von Azodicarbonamid durchgeführt. Aus den Arbeiten lässt sich folgern, dass der Vier-Liter-Autoklav zur Bestimmung und Beschreibung der Deflagrationsfähigkeit von Azodicarbonamid gut geeignet ist und im Vergleich zu Messungen inoffenen Prüfanordnungen eine Reihe von Vorteilen bietet. KW - Deflagration KW - Geschlossener Behälter KW - Autoklav KW - Gas- und Druckmengenmessung PY - 2015 SN - 2191-0073 VL - 5 IS - 6 SP - 39 EP - 44 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-33491 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Scheidemann, Robert A1 - Qiao, Linan A1 - Müller, Karsten A1 - Droste, Bernhard T1 - Determination of material parameters of damping concrete under dynamic loading N2 - The safety and integrity of casks for radioactive waste in accidental scenarios is analysed by BAM Federal institute tor Materials Research and Testing. An accidental scenario in German interim storage facilities is the drop from a crane during the handling operation. To reduce the mechanical loads to the cask a shock absorbing footing with high energy absorption capability is used in these areas. In order to analyse and evaluate such impact scenarios of casks, numerical simulations are performed. For a comprehensive simulation of an accidental scenario the behaviour of the damping concrete footing has to be taken into account as well and therefor a material model is needed. Material parameters under different loading conditions are the basis for a numerical model. For that reason a government funded research project (Kasparek, 2012) was conducted to characterise damping concrete under quasi-static as well as highly dynamic impact loading conditions. The performed tests include compression tests with and without lateral constraint small-scale and midscale penetration tests with different indenters, and finally a full-scale drop test onto a damping concrete footing. T2 - RAMTRANS 2015 - 10th International conference on radioactive materials transport and storage CY - Oxford, UK DA - 19.05.2015 KW - Drop test KW - Damping concrete KW - Material characterisation PY - 2015 SP - 1 EP - 9 AN - OPUS4-33492 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Woydt, Mathias A1 - Mohrbacher, H. T1 - Niobcarbid - Ein vergessener Hartstoff für den Verschleißschutz in offenen und geschlossenen Tribosystemen N2 - Das tribologische Profil von binderlosem NbC und mit 8% bzw. mit 12% Cobalt oder 12% Fe3Al gebundenem NbC wird unter unidirektionaler Gleitreibung (v= 0,1-10 m/s, T= 22°C und 400°C) und unter oszillierender Gleitreibung vergleichend gegenüber Ingenieurkeramiken und Hartmetallen dargestellt. Zusätzlich werden die 4-Punkt-Biegebruchfestigkeit, elastische Eigenschaften (E,G) bis 1.000�C die lastabhängige Mikrohärte sowie die Phasenzusammensetzung und Gefügestrukturen vorgestellt. Die Verschleißkoeffizienten des binderlosen NbC lagen bei T unterhalb von 10-6 mm³/N?m, während diejenigen der cobaltgebundenen NbCs mit ansteigender Gleitgeschwindigkeit von 2-4 10-6 mm³/N?m bei 0,1 m/s auf 5-7 10-7 mm³/N.m bei 10 m/s abnahmen. Die Verschleißkoeffizienten bei 400°C lagen für die NbCs generell unterhalb von 10-6 mm³/N.m. Das tribologische Lasttragevermögen im Trockenlauf, ausgedrückt als PV-Wert, nimmt mit ansteigender Gleitgeschwindigkeit auf 100 W/mm² zu. Bedingt durch die geringe Löslichkeit von NbC in Legierungen offenbarten erste Zerspanversuche mit verschiedenen Stählen eine gegenüber WC-basierten Schneidstoffen signifikant angehobene Zerspanungsvolumina. Somit offenbart NbC in offenen und geschlossenen Tribosystemen Anwendungspotentiale. KW - Gleiten KW - Reibung KW - Verschleiß KW - Oszillation KW - NbC KW - Niobcarbid KW - Cobalt KW - Fe3Al KW - Hartmetall KW - Festigkeit KW - Hohe Temperaturen KW - Sliding KW - Friction KW - Wear KW - Oscillation KW - Niobium carbide KW - Hard metal KW - Strength KW - Modulus KW - High temperatures PY - 2015 SN - 0724-3472 VL - 62 IS - 3 SP - 5 EP - 13 PB - Expert Verlag CY - Renningen AN - OPUS4-33493 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bernicke, M. A1 - Ortel, Erik A1 - Reier, T. A1 - Bergmann, A. A1 - De Araujo, J.F. A1 - Strasser, P. A1 - Kraehnert, R. T1 - Iridium oxide coatings with templated porosity as highly active oxygen evolution catalysts: Structure-activity relationships N2 - Iridium oxide is the catalytic material with the highest stability in the oxygen evolution reaction (OER) performed under acidic conditions. However, its high cost and limited availability demand that IrO2 is utilized as efficiently as possible. We report the synthesis and OER performance of highly active mesoporous IrO2 catalysts with optimized surface area, intrinsic activity, and pore accessibility. Catalytic layers with controlled pore size were obtained by soft-templating with micelles formed from amphiphilic block copolymers poly(ethylene oxide)-b-poly(butadiene)-b-poly(ethylene oxide). A systematic study on the influence of the calcination temperature and film thickness on the morphology, phase composition, accessible surface area, and OER activity reveals that the catalytic performance is controlled by at least two independent factors, that is, accessible surface area and intrinsic activity per accessible site. Catalysts with lower crystallinity show higher intrinsic activity. The catalyst surface area increases linearly with film thickness. As a result of the templated mesopores, the pore surface remains fully active and accessible even for thick IrO2 films. Even the most active multilayer catalyst does not show signs of transport limitations at current densities as high as 75 mA cm-2. KW - Electrochemistry KW - Iridium KW - Structure–activity relationships KW - Template synthesis KW - Water splitting PY - 2015 DO - https://doi.org/10.1002/cssc.201402988 SN - 1864-5631 SN - 1864-564X VL - 8 IS - 11 SP - 1908 EP - 1915 PB - Wiley-VCH CY - Weinheim AN - OPUS4-33503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wäsche, Rolf A1 - Hartelt, Manfred A1 - Hodoroaba, Vasile-Dan T1 - Analysis of nanoscale wear particles from lubricated steel-steel contacts N2 - A new method for sampling wear particles directly from the lubricant reservoir has been developed and applied successfully for analyzing wear particles by high-resolution scanning electron microscopy in transmission mode having coupled energy-dispersive X-ray spectroscopy. The lubricated tribological testing was carried out with fully formulated as well as with non-formulated synthetic base oil. It was possible to analyze individual particles with dimensions as small as about 5–30 nm which are likely the 'primary' wear particles. A majority of the particles, however, are agglomerated and, thus, lead to the formation of larger agglomerates of up to a few micrometers. Chemical analysis led to the conclusion that most of the observed particles generated in formulated oil, especially the larger ones, are composed of the additives of the lubricant oil. In non-formulated base oil, the primary particles are of similar dimensions but contain only iron, chromium and oxygen, but most likely stem from the mating materials. This finding points to the fact that the main wear mechanism under lubricated conditions with fully formulated oil is more like a continuous shearing process rather than a catastrophic failure with the generation of larger primary particles. When the oil is non-formulated, however, several wear mechanisms act simultaneously and the wear rate is increased significantly. Generated larger primary particles are milled down to the nanoscale. When the oil is fully formulated, wear mainly takes places at the additive layer or tribofilm; thus, the steel surface is protected. KW - Particle KW - Wear particle analysis KW - Lubricated contact KW - Bearing steel KW - Nanoscale T-SEM KW - Nanoscale EDX analysis PY - 2015 DO - https://doi.org/10.1007/s11249-015-0534-1 SN - 1023-8883 SN - 1573-2711 VL - 58 IS - 3 SP - 49-1 - 49-10 PB - Springer Science Business Media B.V. CY - Dordrecht AN - OPUS4-33525 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Harsha, A.P. A1 - Wäsche, Rolf A1 - Hartelt, Manfred T1 - Tribological studies on polyetherketone composite under reciprocating sliding condition against steel cylinder N2 - Tribological studies on neat polyetherketone (PEK) and glass fiber reinforced PEK composite were carried out at room and elevated temperature (120 °C). The objective of this study was to characterize for friction and wear properties under dry reciprocating sliding condition at different experimental conditions. The polymer specimens were made to oscillate against steel cylinder as a counterpart. This kind of contact condition are frequently found in bushes, sliding bearing, electronic parts, seals, etc. The friction and wear behavior of neat PEK and composite was quite different at room temperature and elevated temperature. It was observed that glass fiber reinforcement is beneficial in controlling the wear of PEK matrix at room temperature than at elevated temperature. The test results are discussed by considering the surface properties i.e. material removal and film transfer formation. Scanning electron micrographs and optical micrographs of the worn polymer and steel cylinder was used to study the wear mechanisms. KW - Dry oscillating sliding KW - Polyetherketone composite KW - Wear mechanism KW - Contact geometry PY - 2015 DO - https://doi.org/10.1177/1350650115570403 SN - 1350-6501 VL - 229 IS - 7 SP - 795 EP - 806 PB - Institution of Mechanical Engineers CY - London AN - OPUS4-33526 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Epishin, A.I. A1 - Link, T. A1 - Nolze, Gert A1 - Fedelich, Bernard A1 - Schriever, Sina T1 - Creep behaviour of the single-crystal nickel-base superalloy CMSX-4 at ultra-high homologous temperature N2 - Data about the creep behaviour of metals and their alloys at temperatures close to the melting point are very limited. The reason is that most engineering alloys are used at temperatures below 0.6-0.8 of their melting point, so, Investigation of creep at higher temperatures has no practical relevance. For some special applications however it is important, in our case hot isostatic pressing (HIP) of single-crystal turbine blades cast from nickel-base superalloys. In order to remove porosity the blades are HlPed at temperatures between y'-solvus and solidus where superalloy has no strengthening y'-phase and therefore is very soft. For example, the Company Howmet Castings HIPs the superalloy CMSX-4 at the temperature 1288aC, which corresponds to a homologous temperature of about 0.97=1561 K/1612 K (solidus temperature). Therefore knowledge about the creep behaviour of CMSX-4 at this temperature and understanding of the creep mechanisms are necessary to model the kinetics of pore closure during HIP as well as to plan the Parameters of the HIP process. T2 - CREEP 2015 - 13th International conference on creep and fracture of engineering materials and structures CY - Toulouse, France DA - 31.5.2015 PY - 2015 VL - 825 SP - 19 EP - 20 AN - OPUS4-33527 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Olbricht, Jürgen A1 - Bismarck, Marc A1 - Skrotzki, Birgit T1 - Size effects in miniature specimen creep testing of heat resistant ferritic-martensitic steels N2 - The use of miniaturized specimen geometries in mechanical testing allows extracting the sample material directly from the sidewall of critical components of power plants, like e.g. headers and steam pipes. In this way, both the impacts of the processing of the component (including all shaping and tempering influences) and of the exposure to the complex aging/loading/oxidation conditions in the plant (in case of post-Service tests) can be analyzed and representative mechanical properties are obtained. T2 - CREEP 2015 - 13th International conference on creep and fracture of engineering materials and structures CY - Toulouse, France DA - 31.05.2015 PY - 2015 SP - 163 EP - 164 AN - OPUS4-33528 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Theiler, Geraldine A1 - Gradt, Thomas T1 - Einfluss von Wasserstoff auf das Gleitverhalten von graphitgefüllten Polymeren N2 - Die tribologischen Eigenschaften von graphitgefüllten Polyimiden gegen Stahl 100Cr6 wurden an Luft, im Hochvakuum (l0⁻ ³ Pa) und in Wasserstoffumgebung bei verschiedenen Drücken (10³ Pa, 10⁴ Pa und 10⁵ Pa) untersucht. Zwei unterschiedliche Polyimid-Typen wurden eingesetzt, wobei Typ und Menge des Graphits variiert wurden. Die Experimente wurden bei 3,1 MPa Kontaktdruck und einer Gleitgeschwindigkeit von 0,2 m/s bzw. 1 m/s durchgeführt. Die verschlissenen Oberflächen und die Morphologie des Materialübertrags auf die Stahl-Gegenfläche wurden mittels Lichtmikroskopie, REM, TEM und FTIR untersucht. Die Untersuchung zeigt, dass sowohl die Matrix als auch der Graphitanteil einen deutlichen Einfluss auf das Reibverhalten von Verbundwerkstoffen in Wasserstoffumgehungen haben können. N2 - The tribological behaviour of graphite filled polyimide composites against steel (AISI 521 00) was investigated in air, vacuum and hydrogen environment at different pressures (10³ Pa, 10⁴ Pa, and 10⁵ Pa). Composites consist of two polyimides filled with different types and amount of graphite. Friction and wear measurements were performed at 0.2m/s and 3.1MPa at ambient temperature. Wom surfaces and morphology of the material transfer on the steel counter-face were investigated by optical microscopy, SEM, TEM and FTIR analyses. Results reveal that both the polyimide structure and graphite can have an important influence on the friction behaviour of composites in hydrogen environment. KW - Polymere KW - Verbundwerkstoffe KW - Graphit KW - Wasserstoff KW - Vakuum KW - Polymers KW - Composites KW - Graphite KW - Hydrogen KW - Vacuum PY - 2015 SN - 0724-3472 VL - 62 IS - 2 SP - 25 EP - 32 PB - Expert Verlag CY - Renningen AN - OPUS4-33557 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Enrico A1 - Bartholmai, Matthias A1 - Daum, Werner A1 - Gong, Xin A1 - Hofmann, Detlef A1 - Basedau, Frank A1 - Schukar, Vivien A1 - Westphal, Anja A1 - Sahre, Mario A1 - Beck, Uwe T1 - New self diagnostic fiber optical sensor technique for structural health monitoring N2 - Fiber optic sensors have gained increasing importance in recent years and are well established in many areas of industrial applications. In this paper, we introduce a concept of a self-diagnostic fiber optic sensor. The presented sensor is to resolve the problems of embedded fiber optic sensors in complex structures and to enable the validation under operational conditions. For this purpose, different magnetostrictive coated fiber optic sensors were developed and various experiments were performed to verify their mode of operation and to determine the respective reproducibility. The measuring principle is illustrated by obtained experimental results, which showed a change in wavelength from 1 pm at a magnetic field strength change of 0.25 mT. In addition, the temperature characteristics of the implemented magnetostrictive sensor were analyzed and an experimental factor of 1.5 compared to a reference fiber optic sensor was determined. T2 - 32nd Danubia-Adria Symposium on advances in experimental mechanics CY - Starý Smokovec, Slovakia DA - 22.09.2015 PY - 2015 SN - 978-80-554-1094-4 SP - 1 EP - 2 CY - Zilina AN - OPUS4-35173 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Tahri, K. A1 - Tiebe, Carlo A1 - Bougrini, M. A1 - Saidi, T. A1 - El Alami El Hassani, N. A1 - El Bari, N. A1 - Hübert, Thomas A1 - Bouchikhi, B. T1 - Characterization and discrimination of saffron by multisensory systems, SPME-GC-MS and UV-Vis spectrophotometry N2 - Different electronic sensor systems coupled with multivariate data analysis were applied to characterize and classify seven saffron samples and to verify their declared geographical origin. The proposed electronic sensing consists of a low-cost electronic nose (E-nose) based on metal oxide semiconductor sensors and a voltammetric electronic tongue (VE-tongue) based on voltammetric sensors. The ability of multivariable analysis methods such as Principal Component Analysis (PCA), Hierarchical Cluster Analysis (HCA) and Support Vector Machines (SVMs) to classify the saffron samples according to their geographical origin have been investigated. Both PCA and HCA have shown an overlapping of E-nose responses. Moreover, the SVM analysis of the E-nose database reached a 66.07% success rate in the recognition of the saffron sample odour. On the other hand, good discrimination has been reached using PCA and HCA in the VE-tongue characterization case, besides a 100% accuracy in the saffron flavour recognition was attained. To validate the proposed electronic sensing systems, analytical chemical methods such as SPME-GC-MS and UV-Vis spectrophotometry were used. These analytical methods could be helpful tools to identify the composition of volatile compounds of the analysed saffron samples. Moreover, UV-Vis spectrophotometry was also used to determine the non-volatile profile of the samples from different geographic origins. It is demonstrated that the electronic sensing systems' findings are in a satisfactory correlation with the analytical methods. In the light of these results, we might say that the electronic systems offer a fast, simple and efficient tool to recognize the declared geographical origin of the saffron samples. KW - Electronic nose KW - Voltammetric electronic tongue KW - SPME-GC-MS KW - UV-vis spectrophotometry KW - Saffron KW - Geographic differentiation KW - Multivariable analysis PY - 2015 DO - https://doi.org/10.1039/C5AY01986A SN - 1759-9660 SN - 1759-9679 VL - 7 IS - 24 SP - 10328 EP - 10338 PB - RSC Publ. CY - Cambridge AN - OPUS4-35174 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Garces, G. A1 - Perez, P. A1 - Cabeza, Sandra A1 - Lin, H. K. A1 - Kim, S. A1 - Gan, W. A1 - Adeva, Paloma T1 - Reverse tension/compression asymmetry of a Mg-Y-Zn alloys containing LPSO phases N2 - Room temperature mechanical behavior of extruded Mg–Y–Zn alloys with varying fractions of LPSO phase was studied in tension and compression along the extrusion direction. The microstructure is characterised by elongated LPSO fibers along the extrusion direction within the magnesium matrix. Moreover, the magnesium matrix presents a bimodal grain structure with dynamically-recrystallized grains and deformed, elongated grains with the basal plane parallel to the extrusion direction. The beginning of plasticity depends on the volume fraction of deformed and DRX grains. Alloys with low volume fraction of LPSO phase (<10 vol%), with a high volume fraction of deformed grains, show the typical behavior of extruded magnesium alloys where yield stress in tension is higher than in compression. This effect is, however, reversed as the volume fraction of the LPSO phase increases since DRX grains are majority. PY - 2015 DO - https://doi.org/10.1016/j.msea.2015.09.003 SN - 0921-5093 SN - 1873-4936 VL - 647 SP - 287 EP - 293 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-35175 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Masendorf, R. A1 - Müller, C. A1 - Henkel, C. A1 - Klingelhöffer, Hellmuth A1 - Klubberg, F. A1 - Scholz, A. A1 - Wagener, R. ED - Borsutzki, M. ED - Moninger, G. T1 - DIN 50100 Schwingfestigkeitsversuch - Aktueller Stand der Überarbeitung N2 - DIN 50100 definiert die Bedingungen für den Schwingfestigkeitsversuch, der zur Ermittlung von Kennwerten dient, die das Verhalten metallischer Werkstoffe und Bauteile bei zyklischer Beanspruchung mit einer konstanten Lastamplitude beschreiben (Wöhlerversuch). Die Norm umfasst die Versuchsdurchführung, die Versuchsauswertung sowie die Dokumentation von lastgeregelten Wöhlerversuchen im Zeit- und Langzeitfestigkeitsbereich. Mit DIN 50100 soll erreicht werden, dass die Wöhlerlinien verschiedener Prüfstellen miteinander vergleichbar und die wesentlichen Randbedingungen der Versuchsdurchführung dokumentiert werden. Da die Ergebnisse von Schwingfestigkeitsversuchen streuen, ist die Treffsicherheit für die Schätzung der Kennwerte von der Anzahl der Versuche einer Versuchsreihe abhängig. In Abhängigkeit von einer geforderten Treffsicherheit wird durch die DIN 50100 der erforderliche Stichprobenumfang vorgegeben. T2 - Tagung Werkstoffprüfung 2014 - Fortschritte in der Werkstoffprüfung für Forschung und Praxis CY - Bad Neuenahr, Germany DA - 03.12.2015 PY - 2015 SN - 978-3-514-00816-8 SP - 175 EP - 180 PB - Verlag Stahleisen CY - Düsseldorf AN - OPUS4-35176 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yao, Dongxu A1 - Xia, Y. A1 - Zuo, K.-h. A1 - Zeng, Y.-P. A1 - Jiang, D. A1 - Günster, Jens A1 - Heinrich, J.G. T1 - Gradient porous silicon nitride prepared via vacuum foaming and freeze drying N2 - Gradient porous silicon nitride (Si3N4) was fabricated by a novel vacuum foaming and freeze drying process. Aqueous Si3N4 slurries were foamed at vacuum pressure of 50–90 kPa, the green body was obtained by the freeze drying process, a gradient pore structure with porosities of 72–90% was achieved after pressureless sintering at 1680 °C. The porosity was increased with decreasing vacuum pressure. The pore structure consists of large pores (~100 μm) on top, medium pores (~45 μm) on the wall of the large pores, and small pores (~0.7 μm) in the matrix. Such gradient porous Si3N4 with macro- and micro-pores has potential application as high temperature filters. KW - Silicon nitride KW - Graded PY - 2015 DO - https://doi.org/10.1016/j.matlet.2014.11.067 SN - 0167-577x SN - 1873-4979 VL - 141 SP - 138 EP - 140 PB - Elsevier B.V. CY - Amsterdam AN - OPUS4-35177 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Krause, Martin A1 - Kurz, J.H. A1 - Lanata, F. A1 - Krstevska, L. A1 - Cavalli, A. T1 - Needs for further developing monitoring- and NDT-methods for timber structures N2 - For the assessmentand for monitoring of timber structures there are numerous promising methods that enable the quantitative description of the current condition of construction elements or parts of a structure. This concerns material properties like modulus of elasticity, moisture content and density as well as structural properties like dynamic characteristics, localization of inhomogeneities, cracks, and biological attack. During the work in COST Action FP 1101, since 2012 the capability of experimental methods are discussed and compared. This covers electrical and electromagnetic wave methods (resistivity, microwave, Radar, X-Ray), elastic waves (ultrasound, pile testing) and mechanical testing (static and dynamic). Describing and collecting the use of the experimental methods for monitoring purposes was the objective of working group 3 "Monitoring of Timber Structures" of the COST Action. Monitoring capabilities will extend the use of timber structures to further applications in civil engineering. So far, no standard exists but collections of application examples and review papers representing the state of the art. From there needs for further developments regarding monitoring and NDT methods for timber structures can be identified and these are described in this paper. T2 - SHATIS 2015 - 3rd International conference on structural health assessment of timber structures CY - Wroclaw, Poland DA - 09.09.2015 KW - Holz Konstruktionen KW - Monitoring KW - Langzeitverhalten KW - Erdbebensicherheit KW - Historische Bauwerke KW - Ultrasonic echo imaging KW - Historical timber structures KW - Seismic investigation KW - Dynamic tests KW - Anisotropic wave propagation KW - Extending service life PY - 2015 VL - 1 SP - 1 EP - 12 AN - OPUS4-35178 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Torge, Manfred T1 - Mittelalterliche Flachglasherstellung und Glasmalerei N2 - Glas ist ein sehr verbreiteter Werkstoff und eines der ältesten Produkte neben Keramik, Eisen und Bronze, die der Mensch schon frühzeitig herzustellen in der Lage war. Es dauerte jedoch Jahrrausende bis zur ersten wissenschaftliche Beschreibung der Glasstruktur. Sie erfolgte erstmals 1903 von TAMMANN als eine stark unterkühlte Flüssigkeit. VOGEL (1992) gibt einen Überblick über die klassischen Glasstrukturtheorien. Ganz allgernein kann Glas als ein anorganisches Schmelzprodukt definiert werden, das abgekühlt und erstarrt ist, ohne zu kristallisieren, weshalb Glas auch durchsichtig ist. Es kann aus einfachen und nahezu überall und unbegrenzt vorhandenen Rohstoffen hergestellt werden. Die Hauptbestandteile sind Sand, Soda, Pottasche und Kalk. Wesentliche Eigenschaften des Glases sind seine gute Verarbeitbarkeit mir verschiedenartigen Techniken wie Gießen, Blasen, Ziehen und die Möglichkeit, durch die Zugabe von unterschiedlichen Oxiden auch farbige Gläser herzustellen. T2 - 9. Konservierungswissenschaftliches Kolloquium in Berlin/Brandenburg CY - Berlin, Germany DA - 20.11.2015 KW - Mittelalterliches Glas KW - Glaszusammensetzung KW - Glasmalerei PY - 2015 SN - 978-3-7319-0270-6 N1 - Serientitel: Arbeitshefte des Brandenburgischen Landesamtes für Denkmalpflege und Archäologischen Landesmuseums – Series title: Arbeitshefte des Brandenburgischen Landesamtes für Denkmalpflege und Archäologischen Landesmuseums IS - 36 SP - 81 EP - 90 PB - Michael Imhof AN - OPUS4-35115 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Larissa A1 - Herrmann, Antje T1 - Bilder einzelner Zellen aus dem Elementmikroskop N2 - Welche Rolle spielt eine einzelne Zelle im biologischen System? Einen neuen Ansatz, diese Frage zu beantworten, bietet ein Mikroskop auf Basis der Laserablations-ICP-MS, das Elemente in biologischen Materialien analysiert, und zwar mit einer Ortsauflösung im Submikrometerbereich. KW - Elementmikroskop KW - Bio-Imaging KW - LA-ICP-MS KW - Labelilng KW - Nanopartikel PY - 2015 SN - 1439-9598 SN - 1521-3854 VL - 12 IS - 63 SP - 1196 EP - 1199 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-35116 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Avilov, Vjaceslav A1 - Fritzsche, André A1 - Bachmann, Marcel A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Full penetration laser beam welding of thick duplex steel plates with electromagnetic weld pool support N2 - Full penetration high power bead-on-plate laser beam welding tests of up to 20 mm thick 2205 duplex steel plates were performed in PA position. A contactless inductive electromagnetic (EM) weld pool support system was used to prevent gravity drop-out of the melt. Welding experiments with 15 mm thick plates were carried out using IPG fiber laser YLR 20000 and Yb:YAG thin disk laser TruDisk 16002. The laser power needed to achieve a full penetration was found to be 10.9 and 8.56kW for welding velocity of 1.0 and 0.5 m min(-1), respectively. Reference welds without weld pool support demonstrate excessive root sag. The optimal value of the alternating current (AC) power needed to completely compensate the sagging on the root side was found to be approximate to 1.6 kW for both values of the welding velocity. The same EM weld pool support system was used in welding tests with 20 mm thick plates. The laser beam power (TRUMPF Yb:YAG thin disk laser TruDisk 16002) needed to reach a full penetration for 0.5 m min(-1) was found to be 13.9 kW. Full penetration welding without EM weld pool support is not possible-the surface tension cannot stop the gravity drop-out of the melt. The AC power needed to completely compensate the gravity was found to be 2 kW. (C) 2016 Laser Institute of America T2 - ICALEO 2015 - 34th International congress on applications of lasers & electro-optics CY - Atlanta, GA, USA DA - 2015-10-18 KW - Electromagnetic weld pool support KW - Laser beam welding KW - Duplex stainless steel PY - 2015 SN - 978-1-940168-05-0 SP - 571 EP - 579 PB - Amer inst physics CY - Melville, NY, USA AN - OPUS4-35035 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bachmann, Marcel A1 - Kunze, R. A1 - Avilov, Vjaceslav A1 - Rethmeier, Michael T1 - Finite element modelling of an AC electromagnetic weld pool support in full penetration laser beam welding of thick duplex stainless steel plates N2 - An electromagnetic weld pool support system for 20 mm thick duplex stainless steel AISI 2205 was investigated numerically and compared to experiments. In our former publications, it was shown how an AC magnetic field below the process zone directed perpendicular to the welding direction can induce vertically directed Lorentz forces. These can counteract the gravitational forces and allow for a suppression of material drop-out for austenitic stainless steels and aluminum alloys. In this investigation, we additionally adopted a steady-state complex magnetic permeability model for the consideration of the magnetic hysteresis behavior due to the ferritic characteristics of the material. The model was calibrated against the Jiles-Atherton model. The material model was also successfully tested against an experimental configuration before welding with a 30 mm diameter cylinder of austenitic stainless steel surrounded by duplex stainless steel. Thereby, the effects of the Curie temperature on the magnetic characteristics in the vicinity of the later welding zone were simulated. The welding process was modelled with a 3D turbulent steady-state model including heat transfer and fluid dynamics as well as the electromagnetic field equations. Main physical effects, the thermo-capillary (Marangoni) convection at the weld pool boundaries, the natural convection due to gravity as well as latent heat of solid–liquid phase transitions at the phase boundaries were accounted for in the model. The feedback of the electromagnetic forces on the weld pool was described in terms of the electromagneticinduced pressure. The FE software COMSOL Multiphysics 4.2 was used in this investigation. It is shown that the gravity drop-out associated with the welding of 20 mm thick duplex stainless steel plates due to the hydrostatic pressure can be prevented by the application of AC magnetic fields between around 70 mT and 90 mT. The corresponding oscillation frequencies were between 1 kHz and 10 kHz and the electromagnetic AC powers were between 1 kW and 2.3 kW. In the experiments, values of the electromagnetic AC power between 1.6 kW and 2.4 kW at oscillation frequencies between 1.2 kHz and 2.5 kHz were found to be optimal to avoid melt sagging or drop-out of melt in single pass fullpenetration laser beam welding of 15 mm and 20 mm thick AISI 2205. T2 - ICALEO 2015 - 34th International congress on applications of lasers & electro-optics CY - Atlanta, GA, USA DA - 2015-10-18 KW - Electromagnetic weld pool support KW - Laser beam welding KW - FE simulation KW - Duplex stainless steel PY - 2015 SN - 978-1-940168-05-0 SP - 650 EP - 659 AN - OPUS4-35036 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Wieczorek, S. A1 - Schwaar, Timm A1 - Senge, M. O. A1 - Börner, H.G. T1 - Specific drug formulation additives: Revealing the impact of architecture and block length ratio N2 - Combining poly(ethylene glycol) (PEG) with sequence-defined peptides in PEG–peptide conjugates offers opportunities to realize next-generation drug formulation additives for overcoming undesired pharmacological profiles of difficult small molecule drugs. The tailored peptide segments provide sequence-specific, noncovalent drug binding, and the hydrophilic PEG block renders the complexes water soluble. On the basis of a peptide sequence known to bind the photosensitizer m-tetra(hydroxyphenyl)chlorin (m-THPC) for photodynamic cancer therapy, a set of different conjugate architectures is synthesized and studied. Variations in PEG block length and amplification of the peptidic binding domain of PEG–peptide conjugates are used to fine tune critical parameters for hosting m-THPC, such as drug payload capacities, aggregation sizes, and drug release and activation kinetics. PY - 2015 DO - https://doi.org/10.1021/acs.biomac.5b00961 SN - 1525-7797 VL - 16 IS - 10 SP - 3308 EP - 3312 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-35037 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kömmling, Anja A1 - Jaunich, Matthias A1 - Wolff, Dietmar T1 - Alterung von Elastomerdichtungen für Lagerbehälter N2 - Unsere Aufgabe im Fachbereich 3.4 der Bundesanstalt für Materialforschung und prüfung (BAM) ist die sicherheitstechnische Begutachtung von Transport- und Lagerbehältern für radioaktiven Abfall, die für langfristige Zwischenlagerung ausgelegt sind. Ein Arbeitsschwerpunkt ist die Bewertung der Lebensdauer von Metall- und Elastomerdichtungen in den Behältern im Hinblick auf die Anforderungen für langfristige Behältersicherheit (min. 40 Jahre in Deutschland). Um die Eigenschaftsänderungen der Elastomerdichtungen während einer beschleunigten Alterung über lange Zeiträume (bis zu fünf Jahre) untersuchen zu können, wurde ein Alterungsprogramm an ausgewählten Elastomeren (HNBR, EPDM, FKM) begonnen. Im Gegensatz zu Normalterungsverfahren altern wir keine Normteile, sondern O-Ringe im unverpressten sowie verpressten Zustand. Diese Vorgehensweise ermöglicht die Bewertung des Einflusses der Verpressung auf die Alterung sowie die Untersuchung des Bauteilversagens mittels Leckageratenmessungen unter anwendungsnahen Bedingungen. Weitere Charakterisierungsmethoden sind Härtemessung, dynamisch-mechanische Analyse (DMA), Thermogravimetrie (TGA), Druckspannungsrelaxation, Druckverformungsrest (DVR), Dichtebestimmung und Zugversuch. Das Ziel ist, die Leckagerate mit anderen Eigenschaften bzw. Methoden zu korrelieren, um so ein aussagekräftiges und leichter zu bestimmendes Lebensdauerkriterium für elastomere O-Ringe abzuleiten. Während der Alterung können in Abhängigkeit von Material sowie Alterungsdauer und –temperatur Inhomogenitäten aufgrund von diffusionsbegrenzter Oxidation auftreten, durch die sich unterschiedliche Eigenschaften an der Oberfläche und im Volumen der Dichtung ergeben, was zu falschen Lebensdauerabschätzungen führen kann. Mittels Mikrohärtemessung über den Querschnitt werden diese Effekte charakterisiert und bei der Extrapolation mittels Zeit-Temperatur-Verschiebung und Arrheniusgraph berücksichtigt. Bisher liegen Daten von bis zu einem Jahr bei vier verschiedenen Temperaturen (75 °C, 100 °C, 125 °C und 150 °C) gealterten Proben vor. Nach 100 Tagen bei 150 °C weisen HNBR und EPDM schon einen DVR von über 80 % auf, aber noch keinen signifikanten Anstieg der Leckagerate. Diese sinkt zunächst während der Alterung, da die Permeabilität aufgrund von Vernetzungsreaktionen sinkt. Bei HNBR ist dies aufgrund der dominanteren Vernetzungsreaktionen während der Alterung noch stärker ausgeprägt als bei EPDM. T2 - Technomer 2015 - 24. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Germany DA - 12.11.2015 KW - Aging KW - Elastomer KW - Seal KW - Leakage KW - Compression PY - 2015 SN - 978-3-939382-12-6 SP - 43 CY - Chemnitz AN - OPUS4-35050 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Kalbe, Ute A1 - Krüger, Oliver A1 - Bandow, Nicole A1 - Geburtig, Anja ED - Reichert, Thomas T1 - Laboratory Weathering Test for Simulating the Leaching from Artificial Sporting Grounds N2 - In order to estimating the amount and kind of emissions from polymeric sporting tracks a laboratory test was developed in BAM that combines artificial weathering and subsequent batch and column tests [1, 2, 3]. The goal consisted in nvestigating a possible change of emissions into soil and groundwater of a new sporting ground as a function of ageing and egradation of the system. At various stages of the weathering, the samples were removed and subjected to especially designed column extraction tests for the solid samples. Both these extracts and the accumulated rainwater run-off of the weathering device were subjected to analytical tests of their ingredients. The overall aim of the test consisted in developing ontrollable, reproducible, and standardisable conditions and methods of investigation that would allow an estimation of the emissions in the course of outdoor application of about five years. T2 - 7th European Weathering Symposium. Natural and Artificial Ageing of Polymers CY - Naples, Italy DA - 16.09.2015 KW - artificial weathering KW - emission KW - leaching KW - sporting track KW - degradation KW - ageing KW - rubber KW - extraction PY - 2015 SN - 978-3-9816286-6-1 VL - CEES 17 SP - 195 EP - 208 PB - Thomas Würtz CY - Karlsruhe, Germany AN - OPUS4-35401 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - di Matteo, G. A1 - Staude, Andreas A1 - Kuhn, R. A1 - Hertel, I. A1 - Seyfried, F. A1 - Reiche, I. ED - Reiche, I. T1 - Investigation of Ancient Egyptian Metallic Artefacts by Means of Micro-Computed Tomography N2 - In this paper we present the results of imaging studies of ancient Egyptian metallic artifacts using micro-Computed Tomography (micro-CT). Micro-CT is a non-destructive imaging method with high spatial resolution, which enables the examination of the internal structure of objects. It is thus especially suitable for the investigation of cultural heritage and archaeological findings, when it is not possible to sample or difficult to manipulate the object. Using specialized software for 3D visualization and segmentation, data sets of two objects were analyzed. We gained a clear view of the inner structure of a metallic archaeological artifact from the necropolis of Abusir el-Meleq, which is believed to be very ancient in the Egyptian archaeological context (from the Predynastic Era), and were able to distinguish its different omponents under the thick layers of external concretions. These components give hints about the production technology of the object. We also investigated the contents of a closed metal box found near Abusir dated to the Late/Greco-Roman Period. The identified Content corresponds either to sediments or to mineral remains of the original content of the box. Both artifacts are from excavations conducted in Egypt and are part of the archeological collection of the Ägyptisches Museum und Papyrussammlung in Berlin. KW - Computertomographie KW - computed tomography KW - Archäologie KW - archaeology KW - Metall KW - metal PY - 2015 SN - 0344-5089 VL - 23 SP - 79 EP - 84 CY - Berlin AN - OPUS4-35432 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sproesser, Gunther A1 - Chang, Ya-Ju A1 - Pittner, Andreas A1 - Rethmeier, Michael A1 - Finkbeiner, Matthias T1 - Laser-MSG-Hybridschweißen und die Ökobilanz: Sieg nach Punkten N2 - Es ist ein Naturgesetz: Mit der verarbeiteten Blechdicke steigt der Zeit-, Material- und Energiebedarf beim Fügen überproportional. Aber ist das noch umweltverträglich ? Dieser Frage stellte sich Gunther Sproesser mit seinen Kollegen an der Technischen Universität Berlin. KW - MSG-Schweißen KW - Hochleistungsschweißen KW - Ökobilanz KW - Laser-MSG-Hybridschweißen PY - 2015 UR - http://www.laser-community.com/de/schweiss-verfahren-im-oeko-check/ N1 - In Deutsch und Englisch erschienen. Titel in English: "A win on points: LAHW/GMAW welding tops life-cycle analysis study" IS - 21/November 2015 SP - 6 EP - 6 AN - OPUS4-35438 LA - mul AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Köppe, Enrico A1 - Subaric-Leitis, Andreas A1 - Wilk, Tabea T1 - Auswertung der Messunsicherheit eines Multisensorsystems zur Weg- und Positionsbestimmung sich bewegender Objekte in Gebäuden N2 - In den letzten Jahren ist die Bestimmung der Position eines sich bewegenden Objektes eine immer interessanter werdende Information geworden. Die aktuelle Position oder der zurückgelegte Weg wird mittels miniaturisierter integrierter 3D-Sensoren bestimmt. Durch die Integration dieser Sensoren in moderne Smartphones oder in spezielle robuste Hardware sind die Anwendungsgebiete vielseitig. Die ermittelte Position innerhalb von Gebäuden ist dabei für den Kaufmann innerhalb eines Shoppingcenters aber auch für den Feuerwehrmann im Einsatz wichtig. Für den Kaufmann bedeutet es durch gezielte Angebote potenzielle Kunden anzusprechen und damit seinen Umsatz zu steigern. Für den Einsatzleiter der Feuerwehr ist die genaue Position seiner Feuerwehrmänner im Einsatz lebensrettend und bietet damit eine zusätzliche Sicherheit für die Einsatzkraft. Das hier vorgestellte Multisensorsystem, allgemein als Inertialsystem bezeichnet, und das darauf angewendete Verfahren zur Positionsbestimmung wird in diesem Bericht vorgestellt und näher beschrieben. Die systematischen und zufälligen Messunsicherheitsbeiträge des Inertialsystems und deren Auswirkungen auf die Bestimmung der aktuellen Position und somit auf den resultierenden zurückgelegten Weg werden erörtert. T2 - 7. VDI-Fachtagung Messunsicherheit 2015 - Messunsicherheit praxisgerecht bestimmen - Prüfprozesse in der industriellen Praxis CY - Braunschweig, Germany DA - 19.11.2015 PY - 2015 SN - 978-3-18-092269-0 SN - 0083-5560 N1 - Serientitel: VDI-Berichte – Series title: VDI-Berichte IS - 2269 SP - 173 EP - 181 PB - VDI-Verl. AN - OPUS4-35118 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Edel, M. A1 - Köppe, Enrico T1 - An advanced method for pedestrian dead reckoning using BLSTM-RNNs N2 - Location estimation and navigation, especially on smartphones has shown great progress in the past decade due to its low cost and ability to work without additional infrastructure. However, a challenge is the positioning, both in terms of step detection, step length approximation as well as heading estimation, which must be accurate and robust, even when the use of the device is varied in terms of placement or orientation. In this paper, we propose a scheme for retrieving relevant information to detect steps and to estimate the correct step length from raw inertial measurement unit (IMU) data. This approach uses Bidirectional Long Short-Term Memory Recurrent Neural Networks (BLSTM-RNNs). Designed to take contextual information into account, the network can process data gathered from different positions, resulting in a system, which is invariant with respect to transformation and distortions of the input patterns. An experimental evaluation on a dataset produced from 10 individuals demonstrates that this new approach achieves significant improvements over previous attempts and increase the current state-of-the-art results even in the presence of variations and degradations. We achieved a mean classification rate of 98.5% and a standard deviation of 0.70 for 10000 different test sequences and an average error of 1.45% regarding the step length. Thus is the best result on the task gathered in the experiments compared with competing techniques. T2 - IPIN 2015 - 6th International conference on indoor positioning and indoor navigation CY - Banff, Alberta, Canada DA - 13.10.2015 KW - Indoor positioning KW - Inertial tracking KW - Dead reckoning KW - Deep learning KW - Machine learning PY - 2015 SN - 978-1-4673-8402-5 DO - https://doi.org/10.1109/IPIN.2015.7346954 SN - 2162-7347 SP - Paper 1570149259, 1 EP - 6 AN - OPUS4-35119 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Sohail, M. A1 - Han, S.-W. A1 - Na, S.-J. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Numerical investigation of energy input characteristics for high-power fiber laser welding at different positions N2 - Partial penetration welding with a fiber laser at a 9-kW laser power was carried out on 20-mm-thick plates at different positions and analyzed by both experimental and numerical methods. Experiments were carried out for four different angular positions at 1.5 m/min welding speed. All four cases showed a tail-like structure of molten pool on the top surface. The in-depth mechanisms of the energy input characteristics in fiber laser position welding for eight different positions were studied by numerical simulation using the volume-of-fluid (VOF) method. Experimental and numerical results were compared for four cases and showed fair agreement. Observation of flow pattern and bead shape revealed that gravity had little influence on bead shape and flow structure, but changed the pore structure considerably. Flow structure showed a periodic behavior which probably nullified the effect of gravity in position welding. Most of the laser rays reached the bottom of the keyhole without interruption and then multiple reflections started within the keyhole. The first five reflections inside the keyhole delivered around 70 % of the total energy. KW - Laser keyhole welding KW - Fiber laser KW - Partial penetration KW - Position welding KW - Pipe welding PY - 2015 DO - https://doi.org/10.1007/s00170-015-7066-6 SN - 0268-3768 SN - 1433-3015 VL - 80 IS - 5 SP - 931 EP - 946 PB - Springer CY - London AN - OPUS4-35121 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hu, Wei-Hua A1 - Said, Samir A1 - Rohrmann, Rolf A1 - Rücker, Werner A1 - Cunha, A. A1 - Rogge, Andreas ED - De Stefano, A. T1 - Vibration-based structural health monitoring of a highway bridge based on continuous dynamic measurements during 14 years N2 - This paper presents the continuous dynamic measurements of an aging prestressed box-beam bridge during the period from 2000 to 2013, which consists of dynamic properties and environmental/operational factors, as well as the Variation of the extracted health features after removing the environmental/operational effects. Firstly, the variations of frequency estimates, temperatures and traffic loads from 2000 to 2013 are described. Subsequently, correlation analysis between them indicates the nonlinear influences of the temperature on the frequency estimates. The Multiple Linear Regression (MLR) method is used to remove the environmental/operational effects and the health index is proposed by performing the Novelty Detection analysis of the residual errors. Finally, the variations of the health index may indicate clear structural modifications that can be also characterized by the long term monitoring of the dynamic strain in the prestressed cable. T2 - SHMII-7 - 7th International conference on structural health monitoring of intelligent infrastructure CY - Torino, Italy DA - 01.07.2015 KW - Westend bridge PY - 2015 SP - 1 EP - 12 AN - OPUS4-35124 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Häusler, Ines A1 - Moeck, P. A1 - Volz, K. A1 - Neumann, W. T1 - Atomically ordered (Mn,Ga) As crystallites on and within GaAs N2 - Metal organic vapor phase epitaxy (MOVPE) of Mn-rich (Mn,Ga)As on (001) oriented GaAs wafers resulted in atomically ordered (Mn,Ga)As crystallites of two morphological kinds, partially embedded on the wafer surface and fully embedded within the single crystalline matrix. While the former were apparently free of defects (other than unavoidable point defects), the latter contained two domains separated by a grain boundary. Since atomic ordering can be modeled by space group symmetry descent considerations (Bärnighausen trees) that start with the space group of the known crystallographic phases of random (Mn,Ga)As alloys with specified chemical compositions, reasonable structure hypotheses have been derived for two atomically ordered Mn0.75Ga0.25As phases that we call the trigonal α' and the monoclinic β' phases. The implications of these structure hypotheses are in agreement with the results of a range of scanning transmission electron microscopy (STEM) and parallel illumination electron diffraction (ED) studies that include quantitative energy dispersive X-ray spectroscopy, X-ray spectroscopic imaging, as well nanobeam diffraction and high angle precession ED. The coexistence of two domains within the fully embedded crystallites is predicted by the corresponding Bärnighausen tree and observed experimentally for the fully embedded crystallites. KW - (Mn,Ga) As crystallites KW - Bärninghausen symmetry trees KW - Precession electron diffraction KW - Scanning nanobeam mapping KW - STEM/TEM imaging PY - 2015 DO - https://doi.org/10.1002/crat.201500310 SN - 0023-4753 SN - 1521-4079 SN - 0232-1300 VL - 50 IS - 12 SP - 967 EP - 973 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-35125 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Jaunich, Matthias A1 - Grelle, Tobias A1 - Wolff, Dietmar T1 - Influence of partial release on sealing performance of elastomer O-rings at low temperatures N2 - For many sealing applications rubbers are applied due to their special material properties and easy use. In many applications as e.g. in aviation, traffic or process technology the material can be exposed to low temperatures during operation. Therefore it is important to know the material behaviour at those low temperatures to determine the temperature range that allows a safe operation of the seal. As rubbers are used as main sealing materials for containers for low and intermediate level radioactive waste and as additional component to metal seals in spent fuel and high acitve waste containers, a comprehensive elastomer investigation program is run at BAM. This program comprises investigations of elastomer overall performance, durability, influence of gamma irradiation and low temperature behaviour. In this paper we focus on the behaviour of elastomer seals below ambient temperatures after a fast partial release. Despite the primarily static application conditions of many seals their behaviour after partial compression release is of interest with regard to potential decrease of leak-tightness. For this investigation a special setup was designed which allows the partial release of compressed seal systems at different temperatures accompanied by leakage rate measurements. The results for FKM seals are presented and discussed. T2 - Technomer 2015 - 24. Fachtagung über Verarbeitung und Anwendung von Polymeren CY - Chemnitz, Germany DA - 12.11.2015 KW - O-ring KW - Glass-rubber transition KW - Compression set KW - Partial release PY - 2015 SN - 978-3-939382-12-6 SP - P 3.7, 1 EP - 6 CY - Chemnitz AN - OPUS4-35130 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Täuber, K. A1 - Zimathies, Annett A1 - Yuan, J. T1 - Porous membranes built up from hydrophilic poly(ionic liquid)s N2 - Porous polymer membranes made via electrostatic complexation are fabricated from a water-soluble poly(ionic liquid) (PIL) for the first time. The porous structure is formed as a consequence of simultaneous phase separation of the PIL and ionic complexation with an acid, which occurred in a basic solution of a nonsolvent for the PIL. These membranes have a stimuli-responsive porosity, with open and closed pores in isopropanol and in water, respectively. This property is quantitatively demonstrated in filtration experiments, where water is passing much slower through the membranes than isopropanol. KW - Crosslinking KW - Phase separation KW - Poly(ionic liquid) KW - Porous membranes KW - Responsive materials PY - 2015 DO - https://doi.org/10.1002/marc.201500480 SN - 1022-1336 SN - 1521-3927 VL - 36 IS - 24 SP - 2176 EP - 2180 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-35135 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Mull, Birte A1 - Jann, Oliver T1 - Biozidemissionen aus Materialien in die Luft N2 - Die meisten organischen Biozide gehören zu der Gruppe der schwerflüchtigen organischen Verbindungen (SVOC – semi volatile organic compounds). Zu den klassischen Bioziden zählen u.a. Lindan, Pentachlorphenol PCP) und Dichlordiphenyltrichlorethan (DDT) und zu den neueren u.a. Dichlofluanid, Tebuconazol und Permethrin. Biozide kamen in Museen vor allem in den 50er und 60er Jahren zum Schutz der Exponate zum Einsatz,1 wo sie hauptsächlich in Depoträumen zu finden sind, in welchen sie zum akuten und zum präventiven Schutz vor Schadorganismen eingesetzt wurden.2 Im Laufe der Zeit wurde jedoch festgestellt, dass sich der Einsatz von Bioziden negativ auf die menschliche Gesundheit auswirkt und auch zu Schäden an den behandelten Exponaten führen kann. 3 Verschiedene Möglichkeiten der Biozidanalytik und der Einfluss von Senkeneffekten auf die Analytik werden in diesem Beitrag vorgestellt. KW - Biozidanalytik KW - Schwerflüchtige organische Verbindungen KW - Emissionsmesskammer PY - 2015 SP - 12 EP - 14 CY - Berlin AN - OPUS4-35394 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Markus, M. A. A1 - Napp, J. A1 - Behnke, Thomas A1 - Mitkovski, M. A1 - Monecke, S. A1 - Dullin, C. A1 - Kilfeather, S. A1 - Dressel, R. A1 - Resch-Genger, Ute A1 - Alves, F. T1 - Tracking of inhaled near-infrared fluorescent nanoparticles in lungs of SKH-1 mice with allergic airway inflammation N2 - Molecular imaging of inflammatory lung diseases, such as asthma, has been limited to date. The recruitment of innate immune cells to the airways is central to the inflammation process. This study exploits these cells for imaging purposes within the lung, using inhaled polystyrene nanoparticles loaded with the near-infrared fluorescence dye Itrybe (Itrybe-NPs). By means of in vivo and ex vivo fluorescence reflectance imaging of an ovalbumin-based allergic airway inflammation (AAI) model in hairless SKH-1 mice, we show that subsequent to intranasal application of Itrybe-NPs, AAI lungs display fluorescence intensities significantly higher than those in lungs of control mice for at least 24 h. Ex vivo immunofluorescence analysis of lung tissue demonstrates the uptake of Itrybe-NPs predominantly by CD68+CD11c+ECF-L+MHCIIlow cells, identifying them as alveolar M2 macrophages in the peribronchial and alveolar areas. The in vivo results were validated by confocal microscopy, overlapping tile analysis, and flow cytometry, showing an amount of Itrybe-NP-containing macrophages in lungs of AAI mice significantly larger than that in controls. A small percentage of NP-containing cells were identified as dendritic cells. Flow cytometry of tracheobronchial lymph nodes showed that Itrybe-NPs were negligible in lung draining lymph nodes 24 h after inhalation. This imaging approach may advance preclinical monitoring of AAI in vivo over time and aid the investigation of the role that macrophages play during lung inflammation. Furthermore, it allows for tracking of inhaled nanoparticles and can hence be utilized for studies of the fate of potential new nanotherapeutics. KW - Itrybe nanoparticles KW - In vivo near-infrared fluorescence imaging KW - Allergic airway inflammation KW - Cell tracking KW - Alveolar macrophages PY - 2015 DO - https://doi.org/10.1021/acsnano.5b04026 SN - 1936-0851 VL - 9 IS - 12 SP - 11642 EP - 11657 PB - ACS Publ. CY - Washington, DC, USA AN - OPUS4-35302 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Bussian, B. M. A1 - Pandelova, M. A1 - Lehnik-Habrink, Petra A1 - Aichner, Bernhard A1 - Henkelmann, B. A1 - Schramm, K.-W. T1 - Persistent endosulfan sulfate is found with highest abundance among endosulfan I, II, and sulfate in german forest soils N2 - Endosulfan – an agricultural insecticide and banned by Stockholm Convention – is produced as a 2:1 to 7:3 mixture of isomers endosulfan I (ESI) and endosulfan II (ESII). Endosulfan is transformed under aerobic conditions into endosulfan sulfate (ESS). The study shows for 76 sampling locations in German forests that endosulfan is abundant in all samples with an opposite ratio between the ESI and ESII than the technical product, where the main metabolite ESS is found with even higher abundance. The ratio between ESI/ESII and ESS show clear dependence on the type of stands (coniferous vs. deciduous) and humus type and increases from deciduous via mixed to coniferous forest stands. The study argues for a systematic monitoring of ESI, ESII, and ESS and underlines the need for further research, specifically on the fate of endosulfan including biomagnifications and bioaccumulation in soil. KW - Endosulfan KW - Stockholm-Convention KW - Diffuse pollution KW - POPs KW - Soil monitoring KW - Forest soil PY - 2015 SN - 0269-7491 SN - 0013-9327 SN - 1873-6424 VL - 206 SP - 661 EP - 666 PB - Elsevier CY - New York, NY [u.a.] AN - OPUS4-35304 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Madia, Mauro A1 - Zerbst, Uwe T1 - Bruchmechanische Bestimmung der Schwingfestigkeit basierend auf der zyklischen R-Kurve N2 - Konventionell wird in der Bauteilauslegung zwischen Konzepten der Schwing- und Betriebsfestigkeit auf der einen und der Bruchmechanik auf der anderen Seite unterschieden. Werden in der Schwingfestigkeitsbewertung Gesamtlebensdauern ermittelt, so sind es in der Bruchmechanik Restlebensdauern bei Vorhandensein eines größeren, d.h., bereits zerstörungsfrei auffindbaren Risses. Daneben gibt es seit längerem Bestrebungen, bruchmechanische Ansätze auch für die Ermittlung der Gesamtlebensdauer fruchtbar zu machen. Der besondere Wert einer solchen Kombination besteht darin, dass die Bruchmechanik die explizite theoretische Behandlung von Eingangsparametern (Kerben, Oberflächenrauhigkeit, Mittelspannung, etc.) erlaubt, die in den konventionellen Ansätzen mit vergleichsweise hoher Ungenauigkeit halbempirisch einbezogen werden. Der Beitrag stellt einen von den Autoren entwickelten bruchmechanischen Ansatz zur Ermittlung von Wöhlerkurven vor, der eine Reihe innovativer Merkmale wie die Anwendung der elastischplastischen Bruchmechanik auf kurze Risse, die Ermittlung der Ausgangsrissgröße aus Rissarrestbetrachtungen, die Beschreibung der transienten Entwicklung des Rissschließeffekts mit Hilfe zyklischer R-Kurven (Risslängenabhängigkeit des Schwellenwertes von der Risstiefe), die theoretische Erfassung von Mehrfachrisswachstum bei Lastniveaus oberhalb der Dauerfestigkeit und statistische Aspekte umfasst. Das diskutierte Beispiel ist eine Schweißverbindung (Stumpfnaht) und wurde im Rahmen des laufenden Cluster-Projektes IBESS (Integrale bruchmechanische Ermittlung der Schwingfestigkeit von Schweißverbindungen) generiert. T2 - 42. Tagung des DVM-Arbeitskreises Betriebsfestigkeit CY - Dresden, Germany DA - 07.10.2015 KW - Bruchmechanik KW - Schwingfestigkeit KW - Zyklische R-Kurve PY - 2015 SN - 1616-5144 N1 - Serientitel: DVM-Bericht – Series title: DVM-Bericht IS - 142 SP - 285 EP - 296 CY - Berlin AN - OPUS4-35299 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Nachtigall, O. A1 - Kusserow, M. A1 - Clerac, R. A1 - Wernsdorfer, W. A1 - Menzel, Michael A1 - Renz, F. A1 - Mrozinski, J. A1 - Spandl, J. T1 - [Fe19] “Super-Lindqvist” Aggregate and Large 3D Interpenetrating Coordination Polymer from Solvothermal Reactions of [Fe2(OtBu)6] with Ethanol N2 - The syntheses, crystal structures, and physical properties of [HFe19O14(OEt)30] and {Fe11(OEt)24}1 are reported. [HFe19O14(OEt)30] has an octahedral shape. Its core with a central Fe metal ion surrounded by six m6-oxo ligands is arranged in the rock salt structure. {Fe11(OEt)24}1 is a mixedvalence coordination polymer in which FeIII metal ions form three 3D interpenetrating (10,3)-b nets. The arrangement of the FeIII ions can also be compared to that of Si ions in a-ThSi2. Thus, the described structures are at the interface between molecular and solid-state chemistry. KW - Solvothermal syntheses KW - Coordination polymers KW - Koordinationspolymere KW - Iron KW - Eisen KW - Polyoxometalates KW - Single-molecule magnets KW - Einzelmolekülmagnete PY - 2015 DO - https://doi.org/10.1002/anie.201503647 VL - 54 SP - 10361 EP - 10364 PB - Wiley-VCH Verlag GmbH & Co. KGaA CY - Weinheim AN - OPUS4-35368 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Zerbst, Uwe A1 - Klinger, Christian A1 - Clegg, R. T1 - Fracture mechanics as a tool in failure analysis - Prospects and limitations N2 - Although fatigue crack propagation and fracture cause a large part of failure events in industrial practice, fracture mechanics in failure analysis seems to be still a side issue. Starting from an introduction into important basic questions of failure analysis and fracture mechanics, the authors specify what kind of questions in failure analysis can be effectively solved by fracture mechanics (and which can't). They illustrate their discussion with a number of 13 case studies from the literature. Much more pronounced than in the design stage the benefit of fracture mechanics in failure analysis depends on its accuracy. This is limited by both, intrinsic factors of the method and the availability and quality of the input information. The authors discuss the various aspects and provide the reader with some background information which, as they believe, will be helpful for better understanding the prospects and limitations of fracture mechanics in failure analysis and the conditions of its application. KW - Failure analysis KW - Fracture mechanics KW - Fatigue KW - Root cause KW - Accompanying measures PY - 2015 DO - https://doi.org/10.1016/j.engfailanal.2015.07.001 SN - 1350-6307 SN - 1873-1961 VL - 55 SP - 376 EP - 410 PB - Elsevier Science Publ. CY - Oxford AN - OPUS4-33839 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Yin, Huajie A1 - Madkour, Sherif Aly Hassan Aly A1 - Schönhals, Andreas T1 - Unambiguous evidence for a highly mobile surface layer in ultrathin polymer films by specific heat spectroscopy on blends N2 - Despite the decade long controversial discussion on the effect of nanometer confinement on the glass transition temperature (Tg) of ultrathin polymer films, there is still no consistent picture. Here, the dynamic calorimetric glass transition of ultrathin films of a blend, which is miscible in the bulk, is directly investigated by specific heat spectroscopy. By a self-assembling process, a nanometer thick surface layer with a higher molecular mobility is formed at the polymer/air interface. By measuring the dynamic calorimetric Tg in dependence on the film thickness, it was shown that the Tg of the whole film was strongly influenced by that nanometer thick surface layer, with a lower Tg. Since the observed thickness dependence of the dynamic Tg is similar to the thickness dependence of the Tg for thin films of homopolymers, it is concluded that also for homopolymer a highly mobile surface layer is relevant for the widely observed Tg depression. PY - 2015 DO - https://doi.org/10.1021/acs.macromol.5b01259 SN - 0024-9297 SN - 1520-5835 VL - 48 IS - 14 SP - 4936 EP - 4941 PB - American Chemical Society CY - Washington, DC AN - OPUS4-33841 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CHAP A1 - Wille, Frank A1 - Nehrig, Marko A1 - Feldkamp, Martin ED - Sorenson, K.B. T1 - Thermal performance of transportation packages for radioactive materials N2 - Prevention of damage caused by heat is one of the objectives during package safety evaluation. This chapter describes basics of heat transfer and major aspects of regulatory requirements. Package temperature criteria and fire test conditions are explained. Special package design features regarding material properties and safety evaluation concepts are discussed. Experimental fire testing is performed by pool fire or with the help of a furnace. Analysis by numerical or analytical approaches show temperature gradients and whether compliance with the regulatory requirements and specified design temperatures is met. The tightness of the package lid system influenced by geometry changes is in the focus of a holistic thermo-mechanical approach considering the entire mechanical and thermal load conditions according the regulatory requirements. KW - Package KW - Safety KW - Storage KW - Transport KW - Testing KW - Convection KW - Fire test KW - Heat KW - Insulation KW - Thermal analysis PY - 2015 SN - 978-1-78242-309-6 SN - 978-1-78242-322-5 DO - https://doi.org/10.1016/B978-1-78242-309-6.00008-3 N1 - Serientitel: Woodhead publishing series in energy – Series title: Woodhead publishing series in energy IS - 78 SP - Chapter 8, 107 EP - 121 PB - Woodhead Publ. AN - OPUS4-33842 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Krebs, Holger A1 - Schwarz, Silke A1 - Schäfer, Diana A1 - Hasenfelder, Uta T1 - Untersuchung von Versagerzündern N2 - Neben den EG-Baumusterprüfungen und Konformitätsbewertungen, die von der BAM als Benannte Stelle nach den Richtlinien 2014/28/EU und 2013/29/EU durchgeführt werden, gibt es auch immer wieder Anfragen von Behörden, Herstellern oder Anwendern zur gesonderten Überprüfung von Zündern. Diese Anfragen liegen hauptsächlich in den Bereichen Identifizierung von Fundzündern, Untersuchungen an Versagerzündern/überlagerten Zündern sowie externe Qualitätssicherung von Firmen. Die Vorgehensweise und die Prüfmethoden, die bei solchen Untersuchungen zum Einsatz kommen, werden vorgestellt und an Beispielen erläutert. KW - Zünder KW - Identifizierung KW - Prüfungen auf Versagensursache PY - 2015 SN - 0941-4584 VL - 37 IS - 2 SP - 32 EP - 35 PB - Deutscher Sprengverband CY - Siegen AN - OPUS4-33844 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Graf, Benjamin A1 - Schuch, M. A1 - Kersting, R. A1 - Gumenyuk, Andrey A1 - Rethmeier, Michael T1 - Additive process chain using selective laser melting and laser metal deposition N2 - Selective Laser Melting (SLM) and Laser Metal Deposition (LMD) are prominent methods in the field of additive manufacturing technology. While the powder-bed based SLM allows the manufacturing of complex structures, buildrate and part volumes are limited. In contrast, LMD is able to operate with high deposition rates on existing parts, however shape complexity is limited. Utilizing their respective strengths, a combination of these two additive technologies has the potential to produce complex parts with high deposition rates. In this paper, a process chain consisting of additive technologies SLM and LMD is described. The experiments are conducted using the alloys Ti-6Al-4V and Inconel 718. A cylindrical test specimen is produced and the microstructure along the SLM-LMD zone is described. In addition, this process chain was tested in the manufacturing of a turbine blade. The feasibility of implementing this process chain for small batch production is discussed. The results are evaluated to show advantages and limitations of the SLM-LMD process chain. This paper is relevant for industrial or scientific users of additive manufacturing technologies, who are interested in the feasibility of a SLM-LMD process chain and its potential for increased deposition rates. T2 - LiM 2015 - Lasers in manufacturing conference 2015 CY - Munich, Germany DA - 22.06.2015 KW - Macro processing KW - Additive manufacturing KW - Laser metal deposition KW - Ti-6Al-4V KW - Inconel 718 KW - Process chain KW - Deposition rate PY - 2015 SP - 1 EP - 6 AN - OPUS4-33778 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Habel, Wolfgang ED - De Stefano, A. T1 - The role of standardization in establishing new monitoring technologies - example fibre-optic sensors N2 - Sensors for assessment of the structure’s behaviour must work durably and reliably. Even if the performance of produced and delivered sensor is well specified, the sensor's strain characteristics and the performance of an applied sensor can significantly differ from the virgin sensor’s performance. The quality and appropriateness of installation decides over the long-term operability and getting reliable measurement results. The paper shows how important a clear terminology is, which problems might occur when sensor are not well characterized according to Standards or guidelines. Short outlook to experimental methods providing clear knowledge and appropriate Validation of the sensor’s performance for a defined measurement task is given. Finally, the state of-the-art in fibre-optic sensor Standardization is given. T2 - SHMII-7 - 7th International conference on structural health monitoring of intelligent infrastructure CY - Torino, Italy DA - 01.07.2015 KW - SHM KW - Standardization KW - Reliability KW - Fibre-optic sensor KW - Embedded sensor KW - Surface-applied sensor KW - Application KW - Validation KW - Calibration PY - 2015 SP - 1 EP - 10 AN - OPUS4-33779 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Auersch, Lutz T1 - Realistic axle-load spectra for the prediction of ground vibrations form rail traffic N2 - Train passages induce static and dynamic forces on the track, the train-induced vibrations propagate through the soil and excite neighbouring buildings. The problem of train vibrations is divided into the parts emission, which is the excitation by railway traffic (the present contribution), transmission, which is the wave propagation through the soil, and immission, which is the transfer into a building, - The calculation of the axle loads are based on the vehicle-track-soil interaction. This interaction uses the dynamic stiffness of the vehicle (the inertia of the wheelset) and the dynamic stiffness of the track-soil System. Based on various time consuming finite-element boundary-element calculations, an approximate track-soil model has been established. The vehicle-track-soil analysis yields several transfer functions between the various geometric or stiffness irregularities and the axle loads of the train. Geometric irregularities of the vehicle (the wheels) and the track (rail surface and track alignment) are the simplest components. Geometric irregularities of the subsoil (trackbed irregularities) have to be transferred to effective irregularities at rail level. The bending stiffness of the track is filtering out the short-wavelength contribution. Stiffness irregularities occur due to random variations in the bailast or the subsoil, which must also be transferred to effective track irregularities, and due to the discrete rail support on sleepers. The axle loads due to the effective track errors from stiffness variations have their specific vehicle-track transfer function. - All necessary formula for the prediction of axle-load spectra will be presented. The prediction method is compared with axle-box measurements at a Standard ballasted track. Moreover, ground Vibration measurements at numerous sites are exploited for the axle-load spectra and the Validation of the prediction method. T2 - ICSV22 - 22nd International congress on sound and vibration CY - Florence, Italy DA - 12.07.2015 PY - 2015 SN - 978-88-88942-48-3 SN - 2329-3675 SP - 1 EP - 8 AN - OPUS4-33781 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -