TY - CHAP A1 - Gaida, Daniel A1 - Wolf, Christian A1 - Stuhlsatz, André A1 - Lippel, Jens A1 - Bäck, T. A1 - Bongards, Michael A1 - McLoone, S. T1 - State Estimation for Anaerobic Digesters using the ADM1 T2 - Proceedings of International IWA-Symposium on Anaerobic Digestion of Solid Waste and Energy Crops, Vienna, Austria, 2011 Y1 - 2011 ER - TY - CHAP A1 - Stuhlsatz, André A1 - Meyer, Christine A1 - Eyben, Florian A1 - Zielke, Thomas A1 - Meier, Gunter A1 - Schuller, Bjorn T1 - Deep neural networks for acoustic emotion recognition: Raising the benchmarks T2 - 2011 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP) N2 - Deep Neural Networks (DNNs) denote multilayer artificial neural networks with more than one hidden layer and millions of free parameters. We propose a Generalized Discriminant Analysis (GerDA) based on DNNs to learn discriminative features of low dimension optimized with respect to a fast classification from a large set of acoustic features for emotion recognition. On nine frequently used emotional speech corpora, we compare the performance of GerDA features and their subsequent linear classification with previously reported benchmarks obtained using the same set of acoustic features classified by Support Vector Machines (SVMs). Our results impressively show that low-dimensional GerDA features capture hidden information from the acoustic features leading to a significantly raised unweighted average recall and considerably raised weighted average recall. Y1 - 2011 U6 - https://doi.org/10.1109/ICASSP.2011.5947651 SP - 5688 EP - 5691 PB - IEEE ER - TY - JOUR A1 - Henin, Stefano A1 - Petit, Yannick A1 - Rohwetter, Philipp A1 - Stelmaszczyk, Kamil A1 - Hao, Zuoqiang A1 - Nakaema, Walter Morinobu A1 - Vogel, Andreas A1 - Pohl, Tobias A1 - Schneider, Friedhelm A1 - Kasparian, Jérôme A1 - Weber, Konradin A1 - Wöste, Ludger A1 - Wolf, Jean-Pierre T1 - Field measurements suggest the mechanism of laser-assisted water condensation JF - Nature Communications N2 - Because of the potential impact on agriculture and other key human activities, efforts have been dedicated to the local control of precipitation. The most common approach consists of dispersing small particles of dry ice, silver iodide, or other salts in the atmosphere. Here we show, using field experiments conducted under various atmospheric conditions, that laser filaments can induce water condensation and fast droplet growth up to several μm in diameter in the atmosphere as soon as the relative humidity exceeds 70%. We propose that this effect relies mainly on photochemical formation of p.p.m.-range concentrations of hygroscopic Hno3, allowing efficient binary Hno3–H2o condensation in the laser filaments. Thermodynamic, as well as kinetic, numerical modelling based on this scenario semiquantitatively reproduces the experimental results, suggesting that particle stabilization by Hno3 has a substantial role in the laser-induced condensation. KW - Luftreinhaltung KW - Kondensation KW - Laser KW - Niederschlag Y1 - 2011 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:hbz:due62-opus-52439 SN - 2041-1723 VL - 2 IS - 1 PB - Springer Nature ER - TY - CHAP A1 - Vogel, Andreas A1 - Weber, Konradin A1 - Fischer, Christian A1 - van Haren, Günther A1 - Pohl, Tobias A1 - Grobety, Bernhard A1 - Meier, Mario T1 - Airborne in-situ measurements of the Eyjafjallojökull ash plume with a small aircraft and optical particle spectrometers over north-western Germany - comparison between the aircraft measurements and the VAAC-model calculations T2 - Geophysical Research Abstracts: EGU General Assembly 2011 N2 - The eruption of the volcano Eyjafjallajökull (Iceland) in 2010 has caused a transportation of an ash dust plume over large areas of Europe. In April 2010 many airports in Europe were closed for several days because of the volcano ash plume and even in May 2010 several German and European airports were closed for shorter periods because of the danger caused by the volcanic ash dust. The VAAC (Volcanic Ash Advisory Center), London, has continuously published graphics of the predicted spread and dispersion of the volcanic ash plume, which were partly basis for the air traffic restrictions in Germany. In this situation the Laboratory for Environmental Measurement Techniques of the University of Applied Sciences in Duesseldorf has performed 14 measurement flights starting from April 23 2010 to May 21 2010 to get real airborne in-situ dust measurement data over the north-western part of Germany and for comparison with the predicted ash dispersion model data of the VAAC of London in Germany. Moreover, airborne passive DOAS remote sensing measurements have been performed by a mini-DOAS system for SO2-measurements within the plume. In this paper the results of the airborne optical ash particle measurements as well as the remote sensing SO2 measurements will be reported for situations with and without the volcanic plume over northern Germany in detail. Moreover, the measured dust data will be compared with the model dispersion predictions for the ash plume by the VAAC and with European limit concentrations. Main conclusions are: The „ash plume“, found by the aircraft measurement of the Duesseldorf University of Applied Sciences over north western Germany in the “red zone” predicted by the VAAC turned out to be inhomogeneous during the measurement flights Clusters of ash plume sometimes had only a height extension of several hundred meters or less Ash substructures with a horizontal extension of ten kilometres up to several tenth of kilometres could be found Vertical double structures of ash plume could be measured by spiral flights and could be observed visually in horizontal direction Ash plume could be observed visually as small brown layer in horizontal direction Particles collected during flight could be identified as ash particles by electron microscope analysis and chemical analysis KW - Luftreinhaltung KW - Vulkanasche KW - Atmosphärisches Aerosol KW - Eyjafjallajökull KW - Messtechnik Y1 - 2011 VL - 13 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Petit, Y. A1 - Henin, S. A1 - Kasparian, J. A1 - Wolf, J. P. A1 - Rohwetter, P. A1 - Stelmaszczyk, K. A1 - Hao, Z. Q. A1 - Nakaema, W. M. A1 - Wöste, L. A1 - Vogel, A. A1 - Pohl, T. A1 - Weber, Konradin T1 - Influence of pulse duration, energy, and focusing on laser-assisted water condensation JF - Applied Physics Letters N2 - We investigate the influence of laser parameters on laser-assisted water condensation in the atmosphere. Pulse energy is the most critical parameter. Nanoparticle generation depends linearly on energy beyond the filamentation threshold. Shorter pulses are more efficient than longer ones with saturation at ∼1.5 ps. Multifilamenting beams appear more efficient than strongly focused ones in triggering the condensation and growth of submicronic particles, while polarization has a negligible influence on the process. The data suggest that the initiation of laser-assisted condensation relies on the photodissociation of the air molecules rather than on their photoionization. KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1063/1.3546172 SN - 0003-6951 VL - 98 IS - 4 PB - AIP Publishing ER - TY - JOUR A1 - Nehr, Sascha A1 - Bohn, Birger A1 - Fuchs, Hendrik A1 - Hofzumahaus, Andreas A1 - Wahner, Andreas T1 - HO2 formation from the OH + benzene reaction in the presence of O2 JF - Physical Chemistry Chemical Physics KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1039/c1cp20334g SN - 1463-9076 VL - 13 IS - 22 PB - Royal Society of Chemistry (RSC) ER - TY - JOUR A1 - Fuchs, H. A1 - Bohn, Birger A1 - Hofzumahaus, A. A1 - Holland, F. A1 - Lu, K. D. A1 - Nehr, Sascha A1 - Rohrer, F. A1 - Wahner, A. T1 - Detection of HO2 by laser-induced fluorescence: calibration and interferences from RO2 radicals JF - Atmospheric Measurement Techniques N2 - Abstract. HO2 concentration measurements are widely accomplished by chemical conversion of HO2 to OH including reaction with NO and subsequent detection of OH by laser-induced fluorescence. RO2 radicals can be converted to OH via a similar radical reaction sequence including reaction with NO, so that they are potential interferences for HO2 measurements. Here, the conversion efficiency of various RO2 species to HO2 is investigated. Experiments were conducted with a radical source that produces OH and HO2 by water photolysis at 185 nm, which is frequently used for calibration of LIF instruments. The ratio of HO2 and the sum of OH and HO2 concentrations provided by the radical source was investigated and was found to be 0.50 ± 0.02. RO2 radicals are produced by the reaction of various organic compounds with OH in the radical source. Interferences via chemical conversion from RO2 radicals produced by the reaction of OH with methane and ethane (H-atom abstraction) are negligible consistent with measurements in the past. However, RO2 radicals from OH plus alkene- and aromatic-precursors including isoprene (mainly OH-addition) are detected with a relative sensitivity larger than 80 % with respect to that for HO2 for the configuration of the instrument with which it was operated during field campaigns. Also RO2 from OH plus methyl vinyl ketone and methacrolein exhibit a relative detection sensitivity of 60 %. Thus, previous measurements of HO2 radical concentrations with this instrument were biased in the presence of high RO2 radical concentrations from isoprene, alkenes or aromatics, but were not affected by interferences in remote clean environment with no significant emissions of biogenic VOCs, when the OH reactivity was dominated by small alkanes. By reducing the NO concentration and/or the transport time between NO addition and OH detection, interference from these RO2 species are suppressed to values below 20 % relative to the HO2 detection sensitivity. The HO2 conversion efficiency is also smaller by a factor of four, but this is still sufficient for atmospheric HO2 concentration measurements for a wide range of conditions. KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.5194/amt-4-1209-2011 SN - 1867-8548 VL - 4 IS - 6 SP - 1209 EP - 1225 PB - Copernicus ER - TY - CHAP A1 - Grote, Wolfgang A1 - Kastsian, Darya A1 - Mönnigmann, Martin T1 - Optimal power system unit commitment with guaranteed local stability T2 - Proceedings of the 2011 American Control Conference N2 - This article deals with the cost optimal commitment of power systems. System stability is often only considered after solving the commitment problem. We show by example that a cost optimization may result in a mode of operation that, while economically optimal, is unstable or has otherwise unacceptable dynamics. As a remedy, we propose to use the so-called normal vector method, which has been developed for the optimization of nonlinear dynamical systems with stability boundaries and uncertain parameters. We apply the method to a small sample power grid, where the optimization goal is to minimize the energy production costs for a given power consumption. KW - Optimization KW - Power system stability KW - Robustness Y1 - 2011 U6 - https://doi.org/10.1109/ACC.2011.5991058 SN - 2378-5861 SP - 4526 EP - 4531 PB - IEEE ER - TY - CHAP A1 - Faber, Christian A1 - Anthrakidis, Anette A1 - Lanz, Marco A1 - Rusack, Markus A1 - Weis, Fabian A1 - Adam, Mario A1 - Schramm, Sebastian T1 - Barriers to solar process heat applications, T2 - SWC 2011: ISES Solar World Congress, 28 August - 2 September 2011, Kassel, Germany KW - Solare-Prozesswärme-Standards Y1 - 2011 UR - https://proceedings.ises.org/swc2011/proceedings/PDF/Papers.pdf SP - 1326 EP - 1334 CY - Kassel ER - TY - JOUR A1 - Mei, Bastian A1 - Sánchez, Miguel D. A1 - Reinecke, Thomas A1 - Kaluza, Stefan A1 - Xia, Wei A1 - Muhler, Martin T1 - The synthesis of Nb-doped TiO2 nanoparticles by spray drying: an efficient and scalable method JF - Journal of Materials Chemistry Y1 - 2011 U6 - https://doi.org/10.1039/c1jm11431j SN - 1364-5501 VL - 21 IS - 32 SP - 11781 EP - 11790 PB - Royal Society of Chemistry (RSC) ER - TY - JOUR A1 - Kaluza, Stefan A1 - Behrens, Malte A1 - Schiefenhövel, Nora A1 - Kniep, Benjamin A1 - Fischer, Richard A1 - Schlögl, Robert A1 - Muhler, Martin T1 - A Novel Synthesis Route for Cu/ZnO/Al2O3 Catalysts used in Methanol Synthesis: Combining Continuous Consecutive Precipitation with Continuous Aging of the Precipitate JF - ChemCatChem Y1 - 2011 U6 - https://doi.org/10.1002/cctc.201000329 SN - 1867-3899 VL - 3 IS - 1 SP - 189 EP - 199 PB - Wiley ER - TY - JOUR A1 - Yang, Zhengxiong A1 - Kollmannsberger, Stefan A1 - Düster, Alexander A1 - Ruess, Martin A1 - Garcia, Eduardo Grande A1 - Burgkart, Rainer A1 - Rank, Ernst T1 - Non-standard bone simulation: interactive numerical analysis by computational steering JF - Computing and Visualization in Science Y1 - 2011 U6 - https://doi.org/10.1007/s00791-012-0175-y VL - 14 IS - 5 SP - 207 EP - 216 PB - Springer ER - TY - JOUR A1 - Elíasson, Jónas A1 - Palsson, Asgeir A1 - Weber, Konradin T1 - Monitoring ash clouds for aviation JF - Nature KW - Luftreinhaltung Y1 - 2011 U6 - https://doi.org/10.1038/475455b VL - 475 IS - 7357 PB - Springer Nature ER - TY - JOUR A1 - Chattopadhyay, Himadri A1 - Benim, Ali Cemal T1 - Turbulent Heat Transfer Over a Moving Surface Due to Impinging Slot Jets JF - Journal of Heat Transfer Y1 - 2011 U6 - https://doi.org/10.1115/1.4004075 VL - 133 IS - 10 PB - ASME ER - TY - JOUR A1 - Benim, Ali Cemal A1 - Escudier, M. P. A1 - Nahavandi, A. A1 - Nickson, A. K. A1 - Syed, Khawar J. A1 - Joos, F. T1 - Computational analysis of incompressible turbulent flow in an idealised swirl combustor JF - Progess in Computational Fluid Dynamics, An International Journal Y1 - 2011 U6 - https://doi.org/10.1504/pcfd.2011.037571 VL - 11 IS - 1 SP - 42 EP - 45 PB - inderscience ER - TY - JOUR A1 - Maqableh, A. M. A1 - Khadrawi, A. F. A1 - Nimr, M. AlA. A1 - Ammourah, S. A. A1 - Benim, Ali Cemal T1 - Heat transfer characteristics of parallel and counter flow micro-channel heat exchangers with varying wall resistance JF - Progress in Computational Fluid Dynamics, An International Journal Y1 - 2011 U6 - https://doi.org/10.1504/pcfd.2011.042183 VL - 11 IS - 5 PB - inderscience ER - TY - JOUR A1 - Carapezza, M. L. A1 - Barberi, F. A1 - Ranaldi, M. A1 - Ricci, T. A1 - Tarchini, L. A1 - Barrancos, José A1 - Fischer, C. A1 - Perez, N. A1 - Weber, Konradin A1 - Di Piazza, A. A1 - Gattuso, A. T1 - Diffuse CO2 soil degassing and CO2 and H2S concentrations in air and related hazards at Vulcano Island (Aeolian arc, Italy) JF - Journal of Volcanology and Geothermal Research Y1 - 2011 U6 - https://doi.org/10.1016/j.jvolgeores.2011.06.010 VL - 207 IS - 3-4 SP - 130 EP - 144 PB - Elsevier ER -