TY - JOUR A1 - Hempel, M. A1 - Ziegler, Mathias A1 - Schwirzke-Schaaf, S. A1 - Tomm, J.W. A1 - Jankowski, D. A1 - Schröder, D. T1 - Spectroscopic analysis of packaging concepts for high-power diode laser bars N2 - Double-side cooled high-power diode laser bars packaged by different techniques on different types of passive heat sinks are analyzed in terms of packaging-induced strain. Reference data from standard devices being single-side cooled only and packaged by conventional soft and hard soldering are also presented. Thermal profiling across the devices complements the results. The most suitable packaging architecture and technique for double-side cooled bars is identified. Measurements of the laser emission near field and electroluminescence pattern provide direct reference to the functionality of the devices. Furthermore, a type of cross calibration of the methods used for strain analysis is made, since all techniques are applied to the same set of bars. This involves micro photoluminescence, micro Raman, and degree-of-polarization electroluminescence spectroscopy. KW - Spectroscopy KW - Semiconductor laser KW - Thermography KW - High-power diode lasers KW - Non-destructive testing PY - 2012 DO - https://doi.org/10.1007/s00339-012-6799-4 SN - 0947-8396 VL - 107 IS - 2 SP - 371 EP - 377 PB - Springer CY - Berlin AN - OPUS4-25789 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Rauchegger, C. A1 - Bayley, S. A1 - Schröder, Volkmar A1 - Thévenin, D. T1 - Dispersion of heavy gases - experimental results and numerical simulations N2 - The hazardous potential of accidental heavy gas releases, especially those involving flammable and toxic gases, is widely known. In order to predict the area in which these gases are in hazardous concentrations, an estimation of the dispersion of these gases must be carried out. While the hazardous area for flammable heavy gases is determined by the lower flammability limit (ca. >1 vol%), the release of toxic heavy gases can result in a much larger hazardous area. Toxic gases, even in very low concentrations (ca. <3,000 ppm), have the potential to be highly damaging. State-of-the-art dispersion models, such as the VDI Guideline 3783, can be used to estimate the dispersion of heavy gases. However, VDI 3783 gives no method for the prediction of the height and width of a heavy gas cloud, which are both required for quantitative risk analysis as well as for a possible coupling of a Lagrangian particle model with the VDI 3783 heavy gas dispersion model. Therefore, further calculation methods were used to describe these dimensions and were evaluated against experimental studies of the length, width, and height of the heavy and neutral gas field. In addition to that the influence of the source height on the heavy gas dispersion was also examined KW - Process safety KW - Heavy gas KW - Numerical simulation KW - Explosion protection PY - 2015 DO - https://doi.org/10.1002/prs.11723 SN - 1066-8527 SN - 1547-5913 SN - 0278-4513 VL - 34 IS - 3 SP - 280 EP - 285 PB - Wiley InterScience CY - Hoboken, NJ AN - OPUS4-34756 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Mitu, M. A1 - Razus, D. A1 - Schröder, Volkmar T1 - Laminar burning velocities of hydrogen-blended methane-air and natural gas-air mixtures, calculated from the early stage of p(t) records in a spherical vessel N2 - The flammable hydrogen-blended methane–air and natural gas–air mixtures raise specific safety and environmental issues in the industry and transportation; therefore, their explosion characteristics such as the explosion limits, explosion pressures, and rates of pressure rise have significant importance from a safety point of view. At the same time, the laminar burning velocities are the most useful parameters for practical applications and in basic studies for the validation of reaction mechanisms and modeling turbulent combustion. In the present study, an experimental and numerical study of the effect of hydrogen addition on the laminar burning velocity (LBV) of methane–air and natural gas–air mixtures was conducted, using mixtures with equivalence ratios within 0.90 and 1.30 and various hydrogen fractions rH within 0.0 and 0.5. The experiments were performed in a 14 L spherical vessel with central ignition at ambient initial conditions. The LBVs were calculated from p(t) data, determined in accordance with EN 15967, by using only the early stage of flame propagation. The results show that hydrogen addition determines an increase in LBV for all examined binary flammable mixtures. The LBV variation versus the fraction of added hydrogen, rH, follows a linear trend only at moderate hydrogen fractions. The further increase in rH results in a stronger variation in LBV, as shown by both experimental and computed LBVs. Hydrogen addition significantly changes the thermal diffusivity of flammable CH4–air or NG–air mixtures, the rate of heat release, and the concentration of active radical species in the flame front and contribute, thus, to LBV variation. KW - Hydrogen KW - Methane KW - Natural gas KW - Laminar burning velocity (LBV) KW - Closed vessel combustion PY - 2021 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-569083 DO - https://doi.org/10.3390/en14227556 SN - 1996-1073 VL - 14 IS - 22 SP - 1 EP - 16 PB - MDPI CY - Basel AN - OPUS4-56908 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Giurcan, V. A1 - Razus, D. A1 - Mitu, M. A1 - Schröder, Volkmar T1 - Limiting oxygen concentration and minimum inert concentration of fuel-air-inert gaseous mixtures evaluation by means of adiabatic flame temperatures and measured fuel-air lower flammability limits N2 - The present paper aims to re-examine the validity of the linear correlation found between AFTLOC, the adiabatic flame temperature at the apex of the flammability range of fuel-air-inert mixtures (where LOC, the Limiting Oxygen Concentration, is measured) and AFTLFL, the adiabatic flame temperature at the lower flammability limit of fuel-air mixtures (LFL). New sets of experimental measurements of LFL and LOC referring to fuel-air mixtures diluted with N2, CO2 and H2O(vap) from trusted literature sources form a comprehensive database for such evaluation. Both the slope and intercept of correlations AFTLOC = a + b*AFTLFL are dependent on the nature of inert gas and on initial temperature. Based on the linear correlation between AFTLOC and AFTLFL, a procedure for calculation of LOC and MIC (Minimum Inert Concentration) of fuel-air-inert mixtures is presented, using measured or calculated LFL of fuel-air mixtures and their corresponding AFT. The method predicts with reasonable accuracy LOC and MIC of fuel-air-inert mixtures (relative deviations ranging between -14 and +17% when calculated and measured LOC and MIC for fuelair-nitrogen and fuel-air-carbon dioxide at ambient initial conditions are examined). KW - Fuel KW - Limiting oxygen concentration KW - Minimum inert concentration KW - Adiabatic flame temperature KW - Flammability limit PY - 2013 UR - http://www.revistadechimie.ro/pdf/GIURCAN%20V.pdf%2012%2013.pdf SN - 0034-7752 VL - 64 IS - 12 SP - 1445 EP - 1453 PB - sti CY - Bucure AN - OPUS4-29997 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Rauchegger, Christian A1 - Schalau, Bernd A1 - Schmidt, Dirk A1 - Lohse, Volkmar A1 - Schröder, Volkmar A1 - Thévenin, D. T1 - Experimental results from heavy gas dispersions (R134a) N2 - Heavy gases in large quantities are used worldwide in various industries. Past incidents, such as the liquefied gas disaster in Viareggio (2009) have shown that these materials are difficult to handle in a safe manner. According to the German Hazardous Incident Ordinance (StörfallVO 2000 - 12. BIMSchV), plant operators with extended responsibilities must produce a report in which they verify that , in the event of an unintentional gas release, the surrounding area will not be aversely affected. Essential elements of this report are calculations of both the released mass flow and the gas dispersion. Using models such as the VDI guideline 3783 (state of the art in Germany) plant operators are able to predict the characteristics of likely gas dispersions. The presented experimental investigations were carried out at the BAM better understand heavy gas dispersion with high gas concentrations in the air (≥ 1 Vol.-%), as well as concentrations with approximately neutral density characteristics (≤ 3000ppm) in order to test the accuracy of the VDI guideline. The starting point for experimental trials was the heavy gas releases resulting from pipeline, vessel or standard gas bottle leaks, with mass flows of between 20 and 100 g s-1. Investigations on the gas-phase release process focused on the unsteady mass flow associated with releases from standard gas bottles. The experimental results will be used as comparative parameters for future simulations. The goal of these simulations is to develop a model with which calculation of the unsteady mass flow, based on the material characteristics for any gas, is possible. T2 - 7th Global congress on process safety - 2011 Spring meeting CY - Chicago, Illinois, USA DA - 13.03.2011 KW - Heavy gas KW - Gas releases KW - Dispersion KW - Measurement KW - VDI guideline 3783 PY - 2011 SP - 1 EP - 12 AN - OPUS4-23532 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - RPRT A1 - Barbier, J.-P. A1 - Bissolotti, G. A1 - Christian, S. A1 - Cleaver, K. A1 - Heller, D. A1 - Injaian, M. A1 - Schröder, Volkmar A1 - Witte, F. T1 - Safe preparation of compressed oxidant-fuel gas mixtures in cylinders KW - Sicherheitstechnik KW - Biogas KW - Explosionsgrenzen KW - Prozesssicherheit PY - 2007 IS - 139/07/E SP - 1 EP - 36 PB - European Industrial Gases Association (EIGA) CY - Brussels AN - OPUS4-16501 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Bresch, Harald A1 - Meyer-Plath, Asmus A1 - Burgdorf, T. A1 - Packroff, R. A1 - Apel, P. A1 - Adolf, P. A1 - Jesse, A. A1 - Leuschner, C. A1 - Bosse, H. A1 - Dubbert, W. A1 - Epp, A. A1 - Gebel, T. A1 - Götz, M. A1 - Herzberg, F. A1 - Hornbogen, T. A1 - Kersten, N. A1 - Kneuer, C. A1 - Kujath, P. A1 - Pipke, R. A1 - Plitzko, s. A1 - Schlesier, K. A1 - Schröder, F. A1 - Schwirn, K. A1 - Sommer, Y. A1 - Tentschert, J. A1 - Völker, D. A1 - Wolf, T. T1 - 1. Bilanz zur gemeinsamen Forschungsstrategie der Ressortforschungseinrichtungen des Bundes 'Nanotechnologie - Gesundheits- und Umweltrisiken von Nanomaterialien' (2007 - 2011) KW - Nanotechnologie KW - Nanopartikel KW - Nanomaterial KW - Bundesoberbehörden KW - Forschungsstrategie PY - 2013 SP - 1 EP - 124 CY - Berlin AN - OPUS4-28538 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Schröder, K. A1 - Meyer-Plath, Asmus A1 - Keller, D. A1 - Ohl, A. T1 - On the Applicability of Plasma Assisted Chemical Micropatterning to Different Polymeric Biomaterials N2 - A plasma process sequence has been developed to prepare chemical micropatterns on polymeric biomaterial surfaces. These patterns induce a guided localized cell layover at microscopic dimension. Two subsequent plasma steps are applied. In the first functionalization step a microwave ammonia plasma introduces amino groups to obtain areas for very good cell adhesion; the second passivation step combines pattern generation and creation of cell repelling areas. This downstream microwave hydrogen plasma process removes functional groups and changes the linkages of polymer chains at the outermost surfaces. Similar results have been obtained on different polymers including polystyrene (PS), polyhydroxyethylmethacrylate (PHEMA), polyetheretherketone (PEEK), polyethyleneterephthalate (PET) and polyethylenenaphthalate (PEN). Such a rather universal chemical structuring process could widen the availability of biomaterials with specific surface preparations. KW - Microwave plasma KW - Ammonia KW - Hydrogen KW - Polymer surface KW - Cell culture KW - XPS KW - Fluorescence PY - 2002 DO - https://doi.org/10.1023/A:1016239302194 SN - 1084-0184 SN - 1572-8978 VL - 7 IS - 2 SP - 103 EP - 125 PB - Plenum Press CY - New York, NY AN - OPUS4-1729 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Algernon, D. A1 - Arndt, R. A1 - Ebsen, B. A1 - Feistkorn, S. A1 - Friese, M. A1 - Große, C. A1 - Kathage, S. A1 - Keßler, S. A1 - Kurz, J. A1 - Küttenbaum, Stefan A1 - Lohse, C. A1 - Maack, Stefan A1 - Niederleithinger, Ernst A1 - Schickert, M. A1 - Schröder, G. A1 - Taffe, A. A1 - Walther, A. A1 - Wilcke, M. A1 - Wolf, J. A1 - Wöstmann, Jens T1 - Leitfaden zur Erstellung von Prüfanweisungen für die Zerstörungsfreie Prüfung im Bauwesen (ZfP Bau) N2 - Der vorliegende Leitfaden dient zur Unterstützung der Entwicklung und Umsetzung von Prüfanweisungen für ZfP-Verfahren im Bauwesen. Er gibt einen Überblick über Verwendungszweck, Erstellung und Inhalte von Prüfanweisungen unter Berücksichtigung einheitlicher Standardisierungsziele. KW - Prüfanweisung KW - Beton KW - Leitfaden PY - 2022 SN - 978-3-947971-23-7 VL - Richtlinie B-LF 01 SP - 1 EP - 9 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) CY - Berlin ET - Ausgabe April 2022 AN - OPUS4-54985 LA - deu 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 -