TY - CHAP A1 - Jahr, Andreas A1 - Batos, Andrej A1 - Sim, Hunn A1 - Villena Martínez, Jose David T1 - A New Approach for Measuring the Wear Resistance of Cutter Blades T2 - International Conference of Agricultural Engineering – CIGR-AgEng2012, Valencia/Spanien, 8.-12.07.2012 Y1 - 2012 ER - TY - JOUR A1 - Aslan, Erman A1 - Nahavandi, A. A1 - Taymaz, I. A1 - Benim, Ali Cemal T1 - A note on modelling non-rectangular boundaries by the Lattice Boltzmann Method JF - Progress in Computational Fluid Dynamics, An International Journal Y1 - 2012 U6 - https://doi.org/10.1504/pcfd.2012.049815 VL - 12 IS - 6 SP - 433 EP - 438 PB - inderscience ER - TY - CHAP A1 - Ruess, Martin A1 - Varduhn, Vasco A1 - Rank, Ernst A1 - Yosibash, Zohar ED - Bader, Michael T1 - A Parallel High-Order Fictitious Domain Approach for Biomechanical Applications T2 - 11th International Symposium on Parallel and Distributed Computing (ISPDC), 2012 : 25 - 29 June 2012, Munich, Germany ; proceedings Y1 - 2012 UR - http://ieeexplore.ieee.org/document/6341523/ SN - 978-1-4673-2599-8 U6 - https://doi.org/10.1109/ISPDC.2012.45 SP - 279 EP - 285 PB - IEEE CY - Piscataway ER - TY - JOUR A1 - Winkler, Michael A1 - Becker, Klaus A1 - Doolan, Con A1 - Kameier, Frank A1 - Paschereit, Christian Oliver T1 - Aeroacoustic Effects of a Cylinder-Plate Configuration JF - AIAA Journal Y1 - 2012 U6 - https://doi.org/10.2514/1.j051578 VL - 50 IS - 7 SP - 1614 EP - 1620 PB - ARC ER - TY - CHAP A1 - Vogel, Andreas A1 - Weber, Konradin A1 - Eliasson, Jonas A1 - Palsson, Asgeir A1 - Moser, H. M. A1 - Palsson, Thorgeir A1 - von Löwis, S. A1 - Fischer, Christian T1 - Airborne and groundbased measurements of ash particles on Iceland and over Germany during the Grímsvötn eruption May 2011 [Abstract] T2 - Geophysical Research Abstracts:EGU General Assembly 2012, held 22-27 April, 2012 in Vienna, Austria N2 - The eruption of the Grimsvötn volcano in May 2010 posed with its ash plume a thread to the aviation in northern Europe. Because of ash plume forecasts of the VAAC London the airport of Keflavik in Iceland as well as airports in England, Scotland and Scandinavia were closed for some time, which caused the cancellation or change of about 500 flights in Europe. Even in Germany the airports of Bremen, Hamburg and Berlin were closed for several hours on 25 May 2011. During this eruption period in May 2011, a team of the Duesseldorf University of Applied Sciences, the University of Iceland, the University of Reykjavik and the IMO has performed airborne in-situ measurements over Iceland and Germany as well as ground based measurements in the south of Iceland. The ground based measurements were performed continuously during the whole eruption period at two significant positions (Skogar and Hvollsvöllur) with optical particle counters (OPCs). The measurement method was based on measuring the airborne concentrations of the classic aerosol components (PM10, PM2.5 and PM1) and TSP (total suspended particles) every 6 seconds. Additional measurement flights on Iceland were started already one day after the beginning of the eruption (twelve in-situ measurement flights) and marked the spatial and temporal spread of volcanic ash in the atmosphere. For the flights light slow flying piston engine powered airplanes where used. The flights over Iceland focused on the western part of Iceland in the region of Reykjavik and Keflavik and over the international airport in Keflavik and were mostly coordinated by ISAVIA. The measurement flights helped to keep Keflavik International Airport open for many additional hours despite of adverse predictions by the London VAAC model, because it was possible to observe the particle concentration on-line during the flights. In Germany a measurement flight was performed on 25 May 2012 over the northern part of Germany where the volcanic ash cloud was forecasted from the dispersion model of the London VAAC. This flight was performed on the behalf of the German Weather Service (DWD). The measurement flights revealed most time relative low airborne ash concentrations over western Iceland, although the groundbased measured ash concentrations in the south of Iceland nearer to the Grimsvötn were very high. In Germany the measured concentrations during the flight were low enough to be consistent with the re-opening of the airports Bremen, Hamburg and Berlin, which were closed by the authorities for several hours on 25 May 2011 because of high concentration predictions by the VAAC-model. The measurement flights clearly proved that OPCs, based on slow flying piston-motor driven aircrafts, are very suitable for the determination of airborne ash particles during volcanic eruptions. This is an important issue for air traffic safety. KW - Luftreinhaltung Y1 - 2012 UR - https://meetingorganizer.copernicus.org/EGU2012/EGU2012-12854-1.pdf SP - 12854 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Weber, Konradin A1 - Eliasson, J. A1 - Vogel, A. A1 - Fischer, C. A1 - Pohl, T. A1 - van Haren, G. A1 - Meier, M. A1 - Grobéty, B. A1 - Dahmann, D. T1 - Airborne in-situ investigations of the Eyjafjallajökull volcanic ash plume on Iceland and over north-western Germany with light aircrafts and optical particle counters JF - Atmospheric Environment KW - Luftreinhaltung Y1 - 2012 U6 - https://doi.org/10.1016/j.atmosenv.2011.10.030 SN - 1352-2310 VL - 48 SP - 9 EP - 21 PB - Elsevier ER - TY - CHAP A1 - Vogel, Andreas A1 - Weber, Konradin A1 - Fischer, Christian A1 - Prata, A. J. A1 - Durant, A. J. T1 - Aircraft in situ and remote sensing measurements of emissions from Etna volcano, Sicily T2 - Geophysical Research Abstracts: EGU General Assembly 2012 N2 - Volcanoes emit particles (silicates and sulphate aerosol) and gases (e.g., water and sulphur dioxide) which influence the radiative balance of the atmosphere. The rate at which sulphur dioxide oxidises to sulphate aerosol is poorly constrained and measurements of downwind abundance are required to quantify the rate at which this process occurs. During July and November 2011, a series of measurements were performed in emissions from Etna Volcano, Sicily, using the University of Applied Sciences (Dusseldorf) research aircraft. Both in situ and remote sensing instrumentation was simultaneously deployed to quantify the down-wind characteristics of gases and particles in the plume emitted by the volcano. In situ particle characteristics were measured using a Grimm 1.109 optical particle counter (microparticles 0.25-32 microns) and Grimm 1320 diffusion electrometer (nanoparticles 25-300 nanometers). Column abundance of sulphur dioxide was measured using a vertically-pointing differential optical absorption spectrometer (DOAS). These measurements were compared to horizontal pathlength-integrated measurements of sulphur dioxide from the Airborne Volcanic Imaging Object Detector (AVOID). Down-wind plume dispersion was discriminated through a series of aircraft transects below and through the volcanic plume. The emissions contained large amounts of nanoparticles relative to microparticles, which reflects gas-phase nucleation of sulphate aerosol. The AVOID system discriminated horizontal layering of volcanic aerosol at altitudes of up to 12,000 ft from a detection range of >50 km. Plume boundaries were discriminated using a combination of the in situ and DOAS measurements in order to compare to the pathlength-integrated measurements from AVOID. KW - Luftreinhaltung KW - Forschungsflugzeug KW - Messtechnik KW - Telemetrie KW - Schwefeldioxid KW - Vulkanismus KW - Atmosphärisches Aerosol Y1 - 2012 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Yang, Z. A1 - Ruess, Martin A1 - Kollmannsberger, Stefan A1 - Düster, Alexander A1 - Rank, Ernst T1 - An efficient integration technique for the voxel-based finite cell method JF - International Journal for Numerical Methods in Engineering Y1 - 2012 U6 - https://doi.org/10.1002/nme.4269 SN - 1097-0207 VL - 91 IS - 5 SP - 457 EP - 471 PB - Wiley ER - TY - JOUR A1 - Fuchs, H. A1 - Dorn, Hans-Peter A1 - Bachner, M. A1 - Bohn, Birger A1 - Brauers, Theo A1 - Gomm, S. A1 - Hofzumahaus, A. A1 - Holland, F. A1 - Nehr, Sascha A1 - Rohrer, F. A1 - Tillmann, R. A1 - Wahner, A. T1 - Comparison of OH concentration measurements by DOAS and LIF during SAPHIR chamber experiments at high OH reactivity and low NO concentration JF - Atmospheric Measurement Techniques N2 - Abstract. During recent field campaigns, hydroxyl radical (OH) concentrations that were measured by laser-induced fluorescence (LIF) were up to a factor of ten larger than predicted by current chemical models for conditions of high OH reactivity and low NO concentration. These discrepancies, which were observed in forests and urban-influenced rural environments, are so far not entirely understood. In summer 2011, a series of experiments was carried out in the atmosphere simulation chamber SAPHIR in Jülich, Germany, in order to investigate the photochemical degradation of isoprene, methyl-vinyl ketone (MVK), methacrolein (MACR) and aromatic compounds by OH. Conditions were similar to those experienced during the PRIDE-PRD2006 campaign in the Pearl River Delta (PRD), China, in 2006, where a large difference between OH measurements and model predictions was found. During experiments in SAPHIR, OH was simultaneously detected by two independent instruments: LIF and differential optical absorption spectroscopy (DOAS). Because DOAS is an inherently calibration-free technique, DOAS measurements are regarded as a reference standard. The comparison of the two techniques was used to investigate potential artifacts in the LIF measurements for PRD-like conditions of OH reactivities of 10 to 30 s−1 and NO mixing ratios of 0.1 to 0.3 ppbv. The analysis of twenty experiment days shows good agreement. The linear regression of the combined data set (averaged to the DOAS time resolution, 2495 data points) yields a slope of 1.02 ± 0.01 with an intercept of (0.10 ± 0.03) × 106 cm−3 and a linear correlation coefficient of R2 = 0.86. This indicates that the sensitivity of the LIF instrument is well-defined by its calibration procedure. No hints for artifacts are observed for isoprene, MACR, and different aromatic compounds. LIF measurements were approximately 30–40% (median) larger than those by DOAS after MVK (20 ppbv) and toluene (90 ppbv) had been added. However, this discrepancy has a large uncertainty and requires further laboratory investigation. Observed differences between LIF and DOAS measurements are far too small to explain the unexpected high OH concentrations during the PRIDE-PRD2006 campaign. KW - Luftreinhaltung Y1 - 2012 U6 - https://doi.org/10.5194/amt-5-1611-2012 SN - 1867-8548 VL - 5 IS - 7 SP - 1611 EP - 1626 PB - Copernicus ER - TY - CHAP A1 - Weber, Konradin A1 - Reichardt, R. A1 - Fischer, Christian A1 - Moser, H. M. A1 - Eliasson, Jonas ED - Jha, Manoj K. ED - Lazard, Myriam ED - Zaharim, Azami ED - Sopian, Kamaruzzaman T1 - Computational Visualization of Volcanic Ash Plume Concentrations Measured by light Aircrafts over Germany and Iceland during the Recent Eruptions of the Volcanoes Eyjafjallajökull and Grimsvötn T2 - Recent advances in Fluid Mechanics, Heat & Mass Transfer, Biology and Ecology KW - Luftreinhaltung KW - Vulkanasche KW - Visualisierung KW - Eyjafjallajökull KW - Atmosphärisches Aerosol Y1 - 2012 SN - 978-1-61804-065-7 SP - 236 EP - 240 PB - WSEAS ER -