TY  - JOUR
A1  - Bühler, Yves
A1  - Christen, Marc
A1  - Kowalski, Julia
A1  - Bartelt, Perry
T1  - Sensitivity of snow avalanche simulations to digital elevation model quality and resolution
JF  - Annals of Glaciology
N2  - Digital elevation models (DEMs), represent the three-dimensional terrain and are the basic input for numerical snow avalanche dynamics simulations. DEMs can be acquired using topographic maps or remote-sensing technologies, such as photogrammetry or lidar. Depending on the acquisition technique, different spatial resolutions and qualities are achieved. However, there is a lack of studies that investigate the sensitivity of snow avalanche simulation algorithms to the quality and resolution of DEMs. Here, we perform calculations using the numerical avalance dynamics model RAMMS, varying the quality and spatial resolution of the underlying DEMs, while holding the simulation parameters constant. We study both channelized and open-terrain avalanche tracks with variable roughness. To quantify the variance of these simulations, we use well-documented large-scale avalanche events from Davos, Switzerland (winter 2007/08), and from our large-scale avalanche test site, Valĺee de la Sionne (winter 2005/06). We find that the DEM resolution and quality is critical for modeled flow paths, run-out distances, deposits, velocities and impact pressures. Although a spatial resolution of ~25 m is sufficient for large-scale avalanche modeling, the DEM datasets must be checked carefully for anomalies and artifacts before using them for dynamics calculations.
KW  - snow
KW  - avalanche
Y1  - 2011
SN  - 1727-5644
VL  - 52
IS  - 58
SP  - 72
EP  - 80
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - JOUR
A1  - Dachwald, Bernd
A1  - Wurm, Patrick
T1  - Mission analysis and performance comparison for an Advanced Solar Photon Thruster
JF  - Advances in Space Research
Y1  - 2011
SN  - 0273-1177
VL  - 48
IS  - 11
SP  - 1858
EP  - 1868
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Xu, Changsheng
A1  - Feldmann, Marco
A1  - Plescher, Engelbert
T1  - IceMole : Development of a novel subsurface ice probe and testing of the first prototype on the Morteratsch Glacier
T2  - EGU General Assembly 2011 Vienna | Austria | 03 – 08 April 2011
N2  - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth).
Y1  - 2011
ER  - 
TY  - CHAP
A1  - Dachwald, Bernd
A1  - Xu, Changsheng
A1  - Feldmann, Marco
A1  - Plescher, Engelbert
A1  - Digel, Ilya
A1  - Artmann, Gerhard
T1  - Development and testing of a subsurface probe for detection of life in deep ice : [abstract]
N2  - We present the novel concept of a combined drilling and melting probe for subsurface ice research. This probe, named “IceMole”, is currently developed, built, and tested at the FH Aachen University of Applied Sciences’ Astronautical Laboratory. Here, we describe its first prototype design and report the results of its field tests on the Swiss Morteratsch glacier. Although the IceMole design is currently adapted to terrestrial glaciers and ice shields, it may later be modified for the subsurface in-situ investigation of extraterrestrial ice, e.g., on Mars, Europa, and Enceladus. If life exists on those bodies, it may be present in the ice (as life can also be found in the deep ice of Earth).
KW  - Eisschicht
KW  - Sonde
KW  - subsurface probe
KW  - subsurface ice research
Y1  - 2011
ER  - 
TY  - JOUR
A1  - Esch, Thomas
A1  - Funke, Harald
A1  - Roosen, Peter
A1  - Jarolimek, Ulrich
T1  - Biogenic Vehicle Fuels in General Aviation Aircrafts
JF  - MTZ worldwide. 72 (2011), H. 1
Y1  - 2011
N1  - recherchierbar für Angehörige der FH Aachen
SP  - 38
EP  - 43
PB  - Springer Automotive Media
CY  - Wiesbaden
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Falk, F.
A1  - Hendrick, P.
T1  - Control system modifications and their effects on the operation of a hydrogen-fueled Auxiliary Power Unit
JF  - XX international symposium on air breathing engines 2011 : ISABE 2011, Gothenburg, Sweden, 12-16 September, 2011. Vol. 2.
Y1  - 2011
SN  - 9781618391803
N1  - 20th International Symposium on Air Breathing Engines 2011 : (ISABE 2011) : Gothenburg, Sweden, 12-16 September, 2011.
SP  - 929
EP  - 938
PB  - American Institute of Aeronautics and Astronautics
CY  - Reston, VA
ER  - 
TY  - CHAP
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Hendrick, P.
A1  - Recker, E.
T1  - Modification and testing of an engine and fuel control system for a hydrogen fuelled gas turbine
T2  - Progress in Propulsion Physics. Vol. 2
Y1  - 2011
SN  - 978-2-7598-0673-7
SP  - 475
EP  - 486
PB  - EDP Sciences
CY  - Les Ulis
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Börner, Sebastian
A1  - Krebs, W.
A1  - Wolf, E.
T1  - Experimental Characterization of Low NOx Micromix Prototype Combustors for Industrial Gas Turbine Applications
JF  - ASME Turbo Expo 2011 ; Vancouver, Canada, June 6-10, 2011
Y1  - 2011
N1  - GT2011-45305
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Recker, E.
A1  - Bosschaerts, W.
A1  - Boonen, Q.
A1  - Börner, Sebastian
T1  - Parametrical study of the „Micromix“ hydrogen combustion principle
JF  - 10th International Symposium on Experimental and Computational Aerothermodynamics of Internal Flows, ISAIF10-049, Brussels, Belgium, 4-7 July 2011
Y1  - 2011
ER  - 
TY  - CHAP
A1  - Loeb, Horst W.
A1  - Schartner, Karl-Heinz
A1  - Dachwald, Bernd
A1  - Ohndorf, Andreas
A1  - Seboldt, Wolfgang
T1  - An Interstellar – Heliopause mission using a combination of solar/radioisotope electric propulsion
T2  - Presented at the 32nd International Electric Propulsion Conference
N2  - There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft travelling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by ESA.Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope electric propulsion. As a further alternative, we here investigate a combination of solar-electric propulsion and radioisotope-electric propulsion. The solar-electric propulsion stage consists of six 22 cm diameter “RIT-22”ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW BOM is provided by a light-weight solar array. The REP-stage consists of four space-proven 10 cm diameter “RIT-10” ion thrusters that will be operating one after the other for 9 yrs in total. Four advanced radioisotope generators provide 648 W at BOM. The scientific instrument package is oriented at earlier studies. For its mass and electric power requirement 35 kg and 35 W are assessed, respectively. Optimized trajectory calculations, treated in a separate contribution, are based on our “InTrance” method.The program yields a burn out of the REP stage in a distance of 79.6 AU for a usage of 154 kg of Xe propellant. With a C3 = 45,1 (km/s)2 a heliocentric probe velocity of 10 AU/yr is reached at this distance, provided a close Jupiter gravity assist adds a velocity increment of 2.7 AU/yr. A transfer time of 23.8 yrs results for this scenario requiring about 450 kg Xe for the SEP stage, jettisoned at 3 AU. We interpret the SEP/REP propulsion as a competing alternative to solar sail and ballistic/REP propulsion. Omiting a Jupiter fly-by even allows more launch flexibility, leaving the mission duration in the range of the ESA specification.
Y1  - 2011
N1  - 32nd International Electric Propulsion Conference, 11-15 September. Wiesbaden, Germany
SP  - 1
EP  - 7
ER  -