TY - JOUR A1 - Strangfeld, Christoph A1 - Müller-Vahl, H. A1 - Nayeri, C. N. A1 - Paschereit, C. O. A1 - Greenblatt, D. T1 - Airfoil in a high amplitude oscillating stream N2 - A combined theoretical and experimental investigation was carried out with the objective of evaluating theoretical predictions relating to a two-dimensional airfoil subjected to high amplitude harmonic oscillation of the free stream at constant angle of attack. Current theoretical approaches were reviewed and extended for the purposes of quantifying the bound, unsteady vortex sheet strength along the airfoil chord. This resulted in a closed form solution that is valid for arbitrary reduced frequencies and amplitudes. In the experiments, the bound, unsteady vortex strength of a symmetric 18 % thick airfoil at low angles of attack was measured in a dedicated unsteady wind tunnel at maximum reduced frequencies of 0.1 and at velocity oscillations less than or equal to 50 %. With the boundary layer tripped near the leading edge and mid-chord, the phase and amplitude variations of the lift coefficient corresponded reasonably well with the theory. Near the maximum lift coefficient overshoot, the data exhibited an additional high-frequency oscillation. Comparisons of the measured and predicted vortex sheet indicated the existence of a recirculation bubble upstream of the trailing edge which sheds into the wake and modifies the Kutta condition. Without boundary layer tripping, a mid-chord bubble is present that strengthens during flow deceleration and its shedding produces a dramatically different effect. Instead of a lift coefficient overshoot, as per the theory, the data exhibit a significant undershoot. This undershoot is also accompanied by high-frequency oscillations that are characterized by the bubble shedding. In summary, the location of bubble and ist subsequent shedding play decisive roles in the resulting temporal aerodynamic loads. KW - vortex shedding KW - aerodynamics KW - general fluid mechanics PY - 2016 DO - https://doi.org/10.1017/jfm.2016.126 SN - 0022-1120 VL - 2016 IS - 793 SP - 79 EP - 108 AN - OPUS4-35594 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Müller, Maike A1 - Gornushkin, Igor B. A1 - Florek, S. A1 - Mory, D. A1 - Panne, Ulrich T1 - Approach to Detection in Laser-Induced Breakdown Spectroscopy N2 - Gated detection with intensified detectors, e.g., ICCDs, is today the accepted approach for detection of plasma emission in laser-induced breakdown spectroscopy (LIBS). However, these systems are more cost-intensive and less robust than nonintensified CCDs. The objective of this paper is to compare, both theoretically and experimentally, the performance of an intensified (ICCD) and nonintensified (CCD) detectors for detection of plasma emission in LIBS. The CCD is used in combination with a mechanical chopper, which blocks the early continuum radiation from the plasma. The detectors are attached sequentially to an echelle spectrometer under the same experimental conditions. The laser plasma is induced on a series of steel samples under atmospheric conditions. Our results indicate that there is no substantial difference in the performance of the CCD and ICCD. Signal-to-noise ratios and limits of detection achieved with the CCD for Si, Ni, Cr, Mo, Cu, and V in steel are comparable or even better than those obtained with the ICCD. This result is further confirmed by simulation of the plasma emission signal and the corresponding response of the detectors in the limit of quantum (photon) noise. KW - LIBS KW - Detektorvergleich KW - ICCD CCD PY - 2007 DO - https://doi.org/10.1021/ac0621470 SN - 0003-2700 SN - 1520-6882 VL - 79 IS - 12 SP - 4419 EP - 4426 PB - American Chemical Society CY - Washington, DC AN - OPUS4-15044 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Jakubowski, Norbert A1 - Müller, L. A1 - Traub, Heike A1 - Esteban-Fernández, D. A1 - Panne, Ulrich A1 - Herrmann, Antje A1 - Schellenberger, E. A1 - Theuring, F. A1 - Kneipp, Janina T1 - Imaging by laser ablation ICP-MS N2 - ICP-MS is a well-established analytical method which excels by high accuracy, high dynamic range and extremely low limits of detection for most metals. Furthermore ICP-MS offers a very high multi-element coverage so that many elements of the periodic table can be detected simultaneously. In this series of lectures, we want to focus on the historical developments, fundamentals, instrumentation and novel applications of ICP-MS in the life and material sciences. T2 - Ringvorlesung Analytik CY - Humboldt-Universität zu Berlin DA - 23.06.2017 KW - Laser ablation ICP-MS KW - Bio-Imaging PY - 2017 AN - OPUS4-40757 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Jaeger, Carsten A1 - Ritter, D. A1 - Goeritzer, M. A1 - Thiele, A. A1 - Blumrich, A. A1 - Beyhoff, N. A1 - Luettges, K. A1 - Smeir, E. A1 - Kasch, J. A1 - Grune, J. A1 - Müller, O. A1 - Klopfleisch, R. A1 - Foryst-Ludwig, A. A1 - Kintscher, U. T1 - Liver X Receptor Agonist AZ876 Induces Beneficial Endogenous Cardiac Lipid Reprogramming and Protects Against Isoproterenol-Induced Cardiac Damage N2 - Background - It is known that dietary intake of polyunsaturated fatty acids may improve cardiac function. However, relatively high daily doses are required to achieve sufficient cardiac concentrations of beneficial omega‐3 fatty acids. The liver X receptor (LXR) is a nuclear hormone receptor and a crucial regulator of lipid homeostasis in mammals. LXR activation has been shown to endogenously reprogram cellular lipid profiles toward increased polyunsaturated fatty acids levels. Here we studied whether LXR lipid reprogramming occurs in cardiac tissue and exerts cardioprotective actions. Methods and Results - Male 129SV mice were treated with the LXR agonist AZ876 (20 µmol/kg per day) for 11 days. From day 6, the mice were injected with the nonselective β‐agonist isoproterenol for 4 consecutive days to induce diastolic dysfunction and subendocardial fibrosis while maintaining systolic function. Treatment with isoproterenol led to a marked impairment of global longitudinal strain and the E/e' ratio of transmitral flow to mitral annular velocity, which were both significantly improved by the LXR agonist. Histological examination showed a significant reduction in isoproterenol‐induced subendocardial fibrosis by AZ876. Analysis of the cardiac lipid composition by liquid chromatography‐high resolution mass spectrometry revealed a significant increase in cardiac polyunsaturated fatty acids levels and a significant reduction in saturated fatty acids by AZ876. Conclusions - The present study provides evidence that the LXR agonist AZ876 prevents subendocardial damage, improves global longitudinal strain and E/e' in a mouse model of isoproterenol‐induced cardiac damage, accompanied by an upregulation of cardiac polyunsaturated fatty acids levels. Cardiac LXR activation and beneficial endogenous cardiac lipid reprogramming may provide a new therapeutic strategy in cardiac disease with diastolic dysfunction. KW - Heart failure KW - Lipids KW - Liver X receptor KW - Diastolic dysfunction KW - Nuclear receptor PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-529352 DO - https://doi.org/10.1161/JAHA.120.019473 VL - 10 IS - 14 SP - e019473 AN - OPUS4-52935 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Horn, Wolfgang A1 - Kasche, J. A1 - Jann, Oliver A1 - Müller, D. T1 - Emissions- und Geruchsuntersuchungen an Bauprodukten - Ergebnisse eines UFO-Planprojektes T2 - 8th Workshop "Odour and Emissions of Plastic Materials" CY - Kassel, Germany DA - 2006-03-27 KW - Bauprodukte KW - Emissionen KW - Geruch KW - RAL UZ PY - 2006 SP - 13-1- 13-7 CY - Kassel AN - OPUS4-12259 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Kasche, J. A1 - Dahms, A. A1 - Horn, Wolfgang A1 - Jann, Oliver A1 - Müller, D. T1 - Sensory evaluation of building products - Results of a German round robin test T2 - VDI-Tagung CY - Bad Kissingen, Deutschland DA - 2007-11-13 KW - Bauprodukte KW - Emissionen KW - Geruch KW - AbBB-Schema KW - Kammermessungen KW - Blauer Engel PY - 2007 SN - 978-3-18-091995-9 SN - 0083-5560 IS - 1995 SP - 193 EP - 202 PB - VDI-Verl. CY - Düsseldorf AN - OPUS4-16322 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Horn, Wolfgang A1 - Kasche, Johannes A1 - Jann, Oliver A1 - Müller, D. A1 - Plehn, W. T1 - Geruchsintensität und Emissionen von Bauprodukten - Vorstellung des Verfahrens und Laborvergleich KW - Bauprodukte KW - Emissionen KW - Geruch KW - AbBB-Schema KW - Kammermessungen KW - Laborvergleich PY - 2007 SN - 0949-8036 SN - 0039-0771 SN - 1436-4891 VL - 67 IS - 3 SP - 71 EP - 75 PB - Springer-VDI-Verl. CY - Düsseldorf AN - OPUS4-14790 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Agea Blanco, Boris A1 - Blaess, C. A1 - Reinsch, Stefan A1 - Brauer, D. A1 - Müller, Ralf T1 - Sintering and foaming of barium and calcium silicate glass powders N2 - Sintering and foaming of barium and calcium silicate glass powder compacts have been studied for different powder milling. Sintering was measured by means of heating microscopy backed up by XRD, DTA, Vacuum Hot Extraction (VHE) and electron microscopy. Foaming intensity strongly increased with decreasing glass partiefe size. Although powder compacts were uniaxially pressed and sintered in ambient air, foaming was affected by the milling atmosphere and most intensive for milfing in C02. Conformingly, VHE studies revealed that foaming of fully sintered samples was mainly driven by C02, even for powders milled in technical air, Ar and N2. Prolonged storage of air milled barium silicate glass powders in ambient air before pressing and sintering caused further increase of foaming intensity. These findings indicate that carbonaceous species are preferentially trapped to or close beneath the powder surface during milling and later storage. The temperature range of C02 degassing from fully sintered barium and calcium silicate g/ass powder compacts fits the temperature ranges of decomposition of BaC03 and CaC03 mix-milled with the respective barium and calcium silicate glass powders. T2 - IMAPS/ACerS 11th International CICMT conference and exhibition CY - Dresden, Germany DA - 20.04.2015 KW - Sintering KW - Foaming KW - Silicate glass powders KW - Barium and calcium silicate plass powders KW - Degassing PY - 2015 SN - 978-1510804562 SP - 31 EP - 37 AN - OPUS4-35250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hsuan, Y.G. A1 - Schröder, Hartmut A1 - Rowe, K. A1 - Müller, Werner A1 - Greenwood, J. A1 - Cazzuffi, D. A1 - Koerner, R.M. ED - Neil Dixon, T1 - Long-term performance and lifetime prediction of geosynthetics N2 - To properly understand and assess the long-term behaviour of geosynthetic materials it is necessary to investigate the various types of possible degradation mechanims. This includes both chemical and mechanical behaviour, and sometimes even their interactions with one another. Clearly, chemical degradation of geosynthetics depends on the polymer type. For example, polyolefins are vulnerable to oxidation; polyesters are susceptible to hydrolysis; and plasticizers can leach from polyvinyl chloride. This paper describes the concept of these three types of degradation, but focuses on the oxidation of polyolefins since the majority of the geosynthetics is made from this type of polymer. The methods used to predict the lifetime of antioxidants and service life of the geosynthetic material will be illustrated. Furthermore, the influence of temperature, pressure, and ultraviolet light on the service life are also demonstrated. Finally, the current specifications targeting the longevity of different geosynthetics are presented. Regarding mechanical degradation, the paper mainly focuses upon the creep deformation of geogrids and stress crack resistance (SCR) of polyethylene geomembranes and geopipe. The method to assess stress crack resistance is described, and the microscopic mechanisms that lead to such failure are explained. For creep evaluation, different acceleration tests are presented and their applicability with respect to the different types of polymers is illustrated. In addition, the long-term shear behaviour of geocomposites and geosynthetic clay liners is presented. T2 - 4th European Geosynthetics Conference - EuroGeo4 CY - Edinburgh, Scotland, UK DA - 2008-09-07 KW - Geosynthetic KW - Durability KW - Degradation KW - Antioxidant KW - Weathering PY - 2008 SP - 1 EP - 41 AN - OPUS4-17975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Reinsch, Stefan A1 - Nascimento, M.L.F. A1 - Müller, Ralf A1 - Zanotto, E. D. T1 - Crystal growth kinetics in cordierite and diopside glasses in wide temperature ranges N2 - We measured and collected literature data for the crystal growth rate, u(T), of µ-cordierite (2MgO · 2Al2O3 · 5SiO2) and diopside (CaO · MgO · 2SiO2) in their isochemical glass forming melts. The data cover exceptionally wide temperature ranges, i.e. 800–1350 °C for cordierite and 750–1378 °C for diopside. The maximum of u(T) occurs at about 1250 °C for both systems. A smooth shoulder is observed around 970 °C for µ-cordierite. Based on measured and collected viscosity data, we fitted u(T) using standard crystal growth models. For diopside, the experimental u(T) fits well to the 2D surface nucleation model and also to the screw dislocation growth mechanism. However, the screw dislocation model yields parameters of more significant physical meaning. For cordierite, these two models also describe the experimental growth rates. However, the best fittings of u(T) including the observed shoulder, were attained for a combined mechanism, assuming that the melt/crystal interface growing from screw dislocations is additionally roughened by superimposed 2D surface nucleation at large undercoolings, starting at a temperature around the shoulder. The good fittings indicate that viscosity can be used to assess the transport mechanism that determines crystal growth in these two systems, from the melting point Tm down to about Tg, with no sign of a breakdown of the Stokes–Einstein/Eyring equation. KW - Crystal growth KW - Oxide glasses KW - Silicates KW - Kristallwachstumsgeschwindigkeit KW - Kinetik KW - Silikatgläser PY - 2008 DO - https://doi.org/10.1016/j.jnoncrysol.2008.09.007 SN - 0022-3093 VL - 354 IS - 52-54 SP - 5386 EP - 5394 PB - North-Holland Publ. Co. CY - Amsterdam AN - OPUS4-18383 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -