TY - CONF A1 - Mermillod-Blondin, A. A1 - Mauclair, C. A1 - Rosenfeld, A. A1 - Bonse, Jörn A1 - Stoian, R. A1 - Audouard, E. T1 - Time-resolved imaging of bulk a-SiO2 upon various ultrashort excitation sequences N2 - Ultrashort pulses lasers are tools of choice for functionalizing the bulk of transparent materials. In particular, direct photoinscription of simple photonic functions have been demonstrated. Those elementary functions rely on the local refractive index change induced when focusing an ultrashort pulse in the volume of a transparent material. The range of possibilities offered by direct photoinscription is still under investigation. To help understanding, optimizing and assessing the full potential of this method, we developed a time-resolved phase contrast microscopy setup. The imaginary part (absorption) and the real part of the laser-induced complex refractive index can be visualized in the irradiated region. The setup is based on a commercially available phase contrast microscope extended into a pump-probe scheme. The originality of our approach is that the illumination is performed by using a pulsed laser source (i.e. a probe beam). Speckle-related issues are solved by employing adequate sets of diffusers. This laser-microscopy technique has a spatial resolution of 650 nm, and the impulse response is about 300 fs. The laser-induced refractive index changes can be tracked up to milliseconds after the energy deposition. The excitation beam (the pump) is focused with a microscope objective (numerical aperture of 0.45) into the bulk of an a-SiO2 sample. The pump beam can be temporally shaped with a SLM-based pulse shaping unit. This additional degree of flexibility allows for observing different interaction regimes. For instance, bulk material processing with femtosecond and picosecond duration pulses will be studied. T2 - Photonics West 2011 CY - San Francisco, CA, USA DA - 22.01.2011 PY - 2011 DO - https://doi.org/10.1117/12.876687 VL - 7925 IS - 79250R SP - 1 EP - 7 AN - OPUS4-23332 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Geier, M. A1 - Eberstein, M. A1 - Grießmann, H. A1 - Partsch, U. A1 - Völkel, L. A1 - Böhme, R. A1 - Mann, Guido A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Impact of laser treatment on phosphoric acid coated multicrystalline silicon PV-wafers N2 - The selective emitter is a well-known technology for producing highly doped areas under the metallization grid to improve the solar cell performance. In this work, the influence of laser irradiation on phosphoric acid coated multicrystalline silicon PV-wafers on the wafer surface structure, the phosphorous depth distribution and the electrical contact resistance within the laser treated area as well as the electrical series resistance of laserprocessed solar cells was evaluated. Different laser processing settings were tested including pulsed and continuous wave (cw) laser sources (515 nm, 532 nm, 1064 nm wavelength). Complementary numerical simulations using the finite element method (FEM) were conducted to explain the impact of the laser parameters on the melting behavior (melt duration and geometry). It was found that the melt duration is a key parameter for a successful laser Doping process. Our simulations at a laser wavelengths of 515 nm reveal that low-repetition rate (<500 kHz) laser pulses of 300 ns duration generate a melt duration of ~0.35 µs, whereas upon scanning cw-laser radiation at 532 nm prolongates the melt duration by at least one order of magnitude. Experimentally, the widely used ns-laser pulses did not lead to satisfying laser irradiation results. In contrast, cw-laser radiation and scan velocities of less than 2 m/s led to suitable laser doping featuring low electrical resistances in the laser treated areas. T2 - 26th European photovoltaic solar energy conference and exhibition CY - Hamburg, Germany DA - 05.09.2011 KW - Silicon solar cell KW - Selective emitter KW - Laser processing KW - Doping KW - Simulation PY - 2011 SN - 3-936338-27-2 DO - https://doi.org/10.4229/26thEUPVSEC2011-2BV.1.7 SP - 1243 EP - 1247 AN - OPUS4-24995 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Eberstein, M. A1 - Geier, M. A1 - Grießmann, H. A1 - Partsch, U. A1 - Voelkel, L. A1 - Böhme, R. A1 - Pentzien, Simone A1 - Koter, Robert A1 - Mann, Guido A1 - Bonse, Jörn A1 - Krüger, Jörg T1 - Towards an industrial laser doping process for the selective emitter using phosphoric acid as dopant N2 - Different laser supported approaches have already been realized, proving the great potential of laserdoped selective emitters (LDSE). However, it is challenging to establish a low-cost process by using pulsed laser tools. So far a single-step process only leads to satisfying results utilizing cw-lasers. In this paper we have examined a two-step process to produce laser-doped selective emitters on multicrystalline textured standard silicon photovoltaic wafers (90-Ω/sq-Emitter, SiN-antireflection coating (ARC)). The precise ARC removal by near-infrared fs-laser pulses (30 fs, 800 nm), and the doping of uncoated silicon wafers by ns-laser pulses (8 ns, 532 nm) were systematically investigated. In the fs-experiment, optimum conditions for ARC removal were identified. In the nsexperiments under suitable conditions (melting regime), the phosphorous concentration underneath the wafer surface was significantly increased and the sheet resistance was reduced by nearly a factor of two. Moreover, electrical measurements on fired metallization fingers deposited on the laser processed wafers showed low contact resistances. Hence, wafer conditioning with combined fs-laser- and ns-laser-processes are expected to be a promising technology for producing selective emitters. T2 - 26th European photovoltaic solar energy conference and exhibition CY - Hamburg, Germany DA - 05.09.2011 KW - Laser processing KW - Doping KW - Selective emitter KW - Multicrystalline silicon PY - 2011 SN - 3-936338-27-2 DO - https://doi.org/10.4229/26thEUPVSEC2011-2BV.1.2 SP - 1220 EP - 1223 AN - OPUS4-24996 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Anik, Yavuz A1 - Geburtig, Anja A1 - Sturm, Heinz A1 - Meyer-Plath, Asmus ED - Reichert, T. T1 - CarboLifeCycle -weathering-induced degradation of nanoparticle-functionalised composites N2 - A new research project 'CarboLifeCycle', funded by the German Federal Ministry of Education and Research (BMBF), investigates various nanoparticle release scenarios for carbon nanotube-containing polymer composites. The studied weathering concepts and conditions will be described. T2 - 5th European weathering symposium - Natural and artificial ageing of polymers CY - Lisbon, Portugal DA - 21.09.2011 KW - CNT KW - Nanoparticle KW - Weathering KW - Degradation PY - 2011 SN - 978-3-9813136-2-8 N1 - Serientitel: CEEES Publication – Series title: CEEES Publication IS - 15 SP - 125 EP - 135 PB - GUS (Gesellschaft für Umweltsimulation) CY - Pfinztal AN - OPUS4-24503 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Schlegel, Moritz-Caspar A1 - Müller, Urs A1 - Panne, Ulrich A1 - Emmerling, Franziska A1 - Meng, Birgit ED - Rogge, A. ED - Meng, B. T1 - Neue Wege in der Zementanalytik - Hochaufgelöste in-situ Sy-XRD T2 - 52. DAfStb-Forschungskolloquium CY - Berlin, Deutschland DA - 2011-11-07 PY - 2011 SN - 978-3-9814281-0-0 SP - 18 EP - 24 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-25197 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Thiele, Marc A1 - Pirskawetz, Stephan A1 - Baeßler, Matthias A1 - Rogge, Andreas T1 - Untersuchung der Schädigungsevolution in Beton unter Ermüdungsbeanspruchung mit Hilfe der Schallemissionsanalyse N2 - Unter zyklischen Belastungen findet im Beton, wie bei anderen Materialien auch, ein Ermüdungsprozess statt, der letztlich im Versagen des Materials enden kann. Im derzeitigen Erkenntnisstand zum Materialverhalten des Betons gibt es gerade bei dessen Ermüdungsverhalten noch viele nicht oder nicht ausreichend geklärte Fragestellungen. Deshalb wurde in Laborversuchen das Ermüdungsverhalten von Beton unter Druckschwellbeanspruchungen untersucht. Im Fokus dieser Untersuchungen standen dabei die während der Lebensdauer im Materialgefüge ablaufenden Prozesse, die zur Schädigung des Gefüges und schließlich auch zum Ermüdungsversagen führen können. In den Ermüdungsversuchen wurden versuchsbegleitend Dehnungsmessungen, Ultraschall-Laufzeitmessungen und Schallemissionsmessungen an den Proben zur Erfassung der Schädigungsevolution eingesetzt. Die Schallemissionsmessung ist dabei ein wichtiges Instrument, da sie die Rissentwicklungsprozesse detektiert, die die Ursache für die Materialschädigung sind. Mit ihr konnten die unterschiedlichen Phasen der Rissentwicklungen über die gesamte Lebensdauer der Betonproben festgestellt werden. Diese Phasen sind gekennzeichnet durch sich stabilisierende, stabile und instabile Rissprozesse, die entsprechende Auswirkungen auf das Materialverhalten haben. Ein Vergleich mit den Ergebnissen der anderen Messtechniken zeigt den entsprechenden Einfluss der Rissentwicklungen auf die Materialeigenschaften des Betons. T2 - 18. Kolloquium Schallemission CY - Wetzlar, Deutschland DA - 27.10.2011 KW - Beton KW - Ermüdung KW - Schallemission PY - 2011 UR - https://nbn-resolving.org/urn:nbn:de:kobv:b43-247223 SN - 978-3-940283-37-5 IS - DGZfP-BB 131 (Vortrag 02) SP - 1 EP - 8 PB - Deutsche Gesellschaft für Zerstörungsfreie Prüfung (DGZfP) AN - OPUS4-24722 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Weltschev, Margit A1 - Bäßler, Ralph A1 - Otremba, Frank T1 - Use of higher-alloyed metallic materials and duplex steels for transport tanks of dangerous goods N2 - Compatibility evaluations of selected metallic materials under the influence of dangerous goods are published in the BAM-List - Requirements for Tanks for the Transport of Dangerous Goods” as basis for substance-related prototype approvals for tank Containers designed for the carriage of dangerous goods. There is a request of the tank manufacturing industry and transportation Companies to incorporate additional materials into the BAM-List, especially corrosion-resistant materials because of the large number of corrosive dangerous goods. One solution to solve corrosion Problems is to line the tank with a polymer, an alternative solution is the application of high-alloyed stainless steels and nickel-based alloys as there are 1.4529 (XINiCrMoCu 25-20-7, alloy 926), 1.4562 (X1NiCrMoCu32-28-7, alloy 31) and 2.4605 (NiCr23Mo16AI, alloy 59). There is an interest to use cost-efficient steels with high strength values and concomitant adequate corrosion resistance such as duplex steel 1.4362 (X2CrNiN23-4). This steel grade was originally developed as a substitute for the austenitic grades 1.4404 (X2CrNiMo17-12-2) and 1.4571 (X6CrNiMoTi17-12-2). Due to the lower content of the alloy elements nickel and molybdenum this duplex steel is a cost-efficient alternative to molybdenum containing austenite. Due to the limited number of corrosion test results with welded test samples of these high-alloyed materials and the duplex steel under the influence of corrosive dangerous goods a comprehensive test Programme was performed with these materials in Cooperation with ThyssenKrupp VDM and Deutsche Edelstahlwerke GmbH. It can be concluded from the test results that the superaustenitic steels 1.4529 and 1.4562 as well as the nickel-based alloy 2.4605 are a really good alternative as tank materials for the transport of dangerous goods in comparison to the lining of the tanks. The nickel-based alloy 2.4605 shows the best resistance and is suitable as material for tanks transporting all tested corrosive substances. One exception is the temperature limit during the transport of hydrochloric acid. The superaustenit 1.4562 is a resistant material with a wide ränge of application. Exceptions for use are: ammonium bifluoride, brine, 34 % calcium Chloride solution, hydrochloric acid, perchloric acid, 90 % 2-chloropropionic acid, nitrating acid with nitric acid content > 50 % and molten monochloroacetic acid. The alloy is limited suitable for allyl Chloride, aluminum Chloride, copper (II) -Chloride and ferric Chloride. The superaustenit 1.4529 showed the lowest resistance compared to the other two materials. This steel is not resistant in hydrochloric acid, perchloric acid, sodium Chlorite and sodium hypochlorite. The application is limited in the concentration ränge of aqueous Solutions of aluminum Chloride, copper (II) Chloride and ferric Chloride. Due to the reduced alloying content of the duplex steel 1.4362 (X2CrNiN23-4) compared to the austenitic CrNiMo-steels, a lower resistance especially in acidic media like formic, acetic or sulfuric acid was observed. Within the more than 7.000 substances contained in the BAM-List there is a large amount of dangerous goods such as hydrocarbons, alcohols, aldehydes, ketones, ethers, esters, and inorganic alkaline substances which have a large transport volume and do not corrode the duplex steel 1.4362 (X2CrNiN23-4). The test results are included in the actual 11th edition of the BAM-List and therefore available for the costumer. T2 - Stainless steel world conference & exhibition 2011 CY - Maastricht, The Netherlands DA - 29.11.2011 KW - Duplexstahl KW - Tankcontainer KW - Tankfahrzeuge KW - Beständigkeitsbewertung KW - BAM-Liste PY - 2011 SP - 1 EP - 12 PB - KCI Publ. AN - OPUS4-24975 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döhler, M. A1 - Hille, Falk A1 - Mevel, L. A1 - Rücker, Werner ED - Chang, F.-K. T1 - Structural health monitoring during progressive damage test of S101 bridge N2 - For the last decades vibration based identification of damage on civil Engineering structures has become an important issue for maintenance operations on transport infrastructure. Research in that field has been rapidly expanding from classic modal Parameter estimation using measured excitation to modern operational monitoring. Here the difficulty is to regard to the specific environmental and operational influence to the structure under observation. In this paper, two methods accounting for statistical and/or operational uncertainties are applied to measurement data of a progressive damage test on a prestressed concrete bridge. On the base of covariance driven Stochastic Subspace Identification (SSI) an algorithm is developed to monitor and automatically compute confidence intervals of the obtained modal parameters. Furthermore, a null space based non-parametric damage detection method, utilizing a statistical χ2 type test is applied to the measurement data. It can be shown that for concrete bridges the proposed methodology is able to clearly indicate the presence of structural damage, if the damage leads to a change of the structural system. T2 - 8th International workshop on structural health monitoring 2011 CY - Stanford, CA, USA DA - 13.09.2011 KW - Subspace identification KW - Damage detection KW - Convidence intervals KW - Prestressed concrete bridge PY - 2011 SN - 978-1-60595-053-2 VL - 1 SP - 748 EP - 758 PB - DEStech Publications, Inc. AN - OPUS4-24688 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Bettge, Dirk A1 - Ruhl, Aki Sebastian A1 - Bäßler, Ralph A1 - Yevtushenko, Oleksandra A1 - Kranzmann, Axel T1 - Corrosion aspects of materials selection for CO2 transport and storage N2 - The geological storage of carbon dioxide (Carbon Capture and Storage, CCS) in depleted gas reservoirs or in saline aquifers is a widely discussed issue. Carbon dioxide may induce corrosion on the piping steels during compression, transportation and injection. Therefore, selection of appropriate piping steels is a key factor in order to increase the safety and reliability of the CCS technology, and to keep the processes cost-effective. The here described subproject of the COORAL project (German acronym for “C02 purity for capture and storage”) deals with the levels of impurities in the C02 stream that will be acceptable when using specific steels. Material exposure to carbon dioxide (C02) containing specific amounts of water vapor, oxygen (02) sulfur dioxide (S02), nitrogen dioxide (N02), carbon monoxide (CO) can be a challenge to steels. Within this subproject 13 different Steels are tested for suitability as materials used for compression, transportation and injection Units within the CCS chain. T2 - 2nd ICEPE International conference on energy process engineering - Efficient carbon capture for coal power plants CY - Frankfurt/M., Germany DA - 20.06.2011 KW - Carbon capture KW - CCS KW - Corrosion PY - 2011 SP - 76 EP - 78 AN - OPUS4-24250 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Döhler, M. A1 - Hille, Falk A1 - Lam, X.-B. A1 - Mevel, L. A1 - Rücker, Werner ED - Proulx, T. T1 - Confidence intervals of modal parameters during progressive damage test N2 - In Operational Modal Analysis, the modal parameters (natural frequencies, damping ratios and mode shapes) obtained from Stochastic Subspace Identification (SSI) of a structure, are afflicted with statistical uncertainty. For evaluating the quality of the obtained results it is essential to know the respective confidence intervals of these figures. In this paper we present algorithms that automatically compute the confidence intervals of modal parameters obtained from covarianceand data-driven SSI of a structure based on vibration measurements. They are applied to the monitoring of the modal parameters of a prestressed concrete highway bridge during a progressive damage test that was accomplished within the European research project IRIS. Results of the covariance- and data-driven SSI are compared. T2 - 29th IMAC - Conference on structural dynamics CY - Jacksonville, FL, USA DA - 31.01.2011 KW - Stochastische subspace basierte Identifikation KW - Schadensdetektion KW - Spannbetonbrücke PY - 2011 SN - 978-1-4419-9304-5 DO - https://doi.org/10.1007/978-1-4419-9305-2_17 SN - 2191-5644 N1 - Serientitel: Conference Proceedings of the Society for Experimental Mechanics Series – Series title: Conference Proceedings of the Society for Experimental Mechanics Series VL - 4 SP - 237 EP - 250 PB - Springer AN - OPUS4-24335 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Hille, Falk A1 - Döhler, M. A1 - Mevel, L. A1 - Rücker, Werner ED - De Roeck, G. ED - Degrande, G. ED - Lombaert, G. ED - Müller, G. T1 - Subspace-based damage detection methods on a prestressed concrete bridge N2 - For the last decades vibration based damage detection of engineering structures has become an important issue for maintenance operations on transport infrastructure. Research in vibration based structural damage detection has been rapidly expanding from classic modal parameter estimation to modern operational monitoring. Methodologies from control Engineering especially of aerospace applications have been adopted and converted for the application on civil structures. Here the difficulty is to regard to the specific environmental and operational influence to the structure under observation. A null space based damage detection algorithm is tested for its sensitivity to structural damage of a prestressed concrete road bridge. Specific techniques and extensions of the algorithm are used to overcome difficulties from the size of the structure which is associated with the number of recorded sensor channels as well as from the operational disturbances by a nearby construction site. It can be shown that for concrete bridges the proposed damage detection methodology is able to clearly indicate the presence of structural damage, if the damage leads to a significant change of the structural system. Small damage which do not result in a System change when not activated by loading, do not lead to a modification of the dynamic response behavior and for that cannot be detected with the proposed global monitoring method. T2 - EURODYN 2011 - 8th International conference on structural dynamics CY - Leuven, Belgium DA - 04.07.2011 KW - Subspace methods KW - Fault detection KW - Monitoring techniques KW - Concrete bridge PY - 2011 SN - 978-90-760-1931-4 IS - MS12 TUE 11:45 SP - 2304 EP - 2310 AN - OPUS4-24689 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Dülsen, Steffen A1 - Hofmann-Böllinghaus, Anja A1 - Krause, Ulrich T1 - Untersuchung zu Brandursachen und Brandverlauf bei Busbränden N2 - Busbrände treten relativ häufig auf, auch wenn sich das im öffentlichen Bewusstsein nicht unbedingt widerspiegelt. Nach einer eigenen Internetrecherche brennt etwa an jedem zweiten Tag ein Bus in Deutschland. Die grundlegenden Brandschutzvorschriften für Busse gehen auf die amerikanische Norm FMVSS 302 zurück, die in den 60er Jahren entwickelt wurde und ist quasi weltweit noch immer in sämtlichen nationalen und internationalen Brandschutzvorschiften wiederzufinden. Ziel der FMVSS 302 ist es vor allem, Fahrzeugbrände durch das Rauchen zu verhindern. Verschiedene Untersuchungen zeigen jedoch, dass die meisten Busbrände andere Ursachen haben und zu ca. 80 % im Motorraum entstehen. Auch das Versagen von elektrischen Komponenten ist häufiger die Brandursache. Dies geschah z.B. im Jahr 2008 bei einem schweren Busbrand in der Nähe von Hannover, bei dem sich gerade einmal 13 Passagiere selber retten konnten und 20 Menschen ihr Leben verloren. Einige Brandleichen wurden sogar noch am Sicherheitsgurt angeschnallt aufgefunden. Durch die enorme Zunahme brennbarer Kunststoffteile in Bussen entstand ein bisher unberücksichtigtes Risiko, das bei der Normentwicklung in den 1960er Jahren nicht berücksichtigt wurde. So hat sich die Brandlast seitdem etwa verzehnfacht und das toxische Potential erheblich gesteigert. Nach wenigen Minuten muss bei den Brandopfern bereits mit einem schnellen Tod durch Rauchgasvergiftungen gerechnet werden. Aufgrund der schnellen Brandentwicklung in Bussen können Passagiere in den allermeisten Fällen nicht bis zum Eintreffen der Feuerwehr warten und müssen sich selber retten. Die Zeit für die Selbstrettung muss signifikant verlängert werden, so dass auch mobilitätseingeschränkte Passagiere eine Chance zum Verlassen des Busses haben. Der Vergleich mit Brandschutzanforderungen anderer Transportsektoren (Bahn, Schiff, Flugzeug) zeigt, dass die Anforderungen dort sehr viel höher sind. Sowohl die Entflammbarkeit als auch die Wärmefreisetzung sowie die Rauchfreisetzung werden in diesen Normen begrenzt. Zudem werden Materialanforderungen hinsichtlich der Rauchgastoxizität gestellt. Im Ergebnis dieser Arbeit sollen einerseits Brandschutzempfehlungen für die zweckmäßige und zugleich wirtschaftlich vertretbare Ausstattung von Bussen im Innenbereich unterbreitet werden. Andererseits sollen auch Überarbeitungsvorschläge für Prüftests vorgestellt werden, die den Brandschutz von Kraftomnibussen sicherstellen und erstmals auch Grenzwerte für die Rauchgastoxizität beinhalten. Dazu werden neben den Brandversuchen auch numerische Simulationen mit dem Fire Dynamics Simulator (FDS, Version 5, NIST) durchgeführt, in denen verschiedene Brandszenarien mit unterschiedlichen Buskategorien simuliert werden. T2 - 59. vfdb-Jahresfachtagung CY - Berlin, Deutschland DA - 2011-05-30 PY - 2011 SP - 805 EP - 816 AN - OPUS4-23847 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -