TY  - JOUR
A1  - McArdell, Brian W.
A1  - Bartelt, Perry
A1  - Kowalski, Julia
T1  - Field observations of basal forces and fluid pore pressure in a debris flow
JF  - Geophysical Research Letters (GRL)
N2  - Using results from an 8 m2 instrumented force plate we describe field measurements of normal and shear stresses, and fluid pore pressure for a debris flow. The flow depth increased from 0.1 to 1 m within the first 12 s of flow front arrival, remained relatively constant until 100 s, and then gradually decreased to 0.5 m by 600 s. Normal and shear stresses and pore fluid pressure varied in-phase with the flow depth. Calculated bulk densities are ρb = 2000–2250 kg m−3 for the bulk flow and ρf = 1600–1750 kg m−3 for the fluid phase. The ratio of effective normal stress to shear stress yields a Coulomb basal friction angle of ϕ = 26° at the flow front. We did not find a strong correlation between the degree of agitation in the flow, estimated using the signal from a geophone on the force plate, and an assumed dynamic pore fluid pressure. Our data support the idea that excess pore-fluid pressures are long lived in debris flows and therefore contribute to their unusual mobility.
KW  - debris flow
Y1  - 2007
SN  - 0094-8276
VL  - 34
IS  - 7
ER  - 
TY  - CHAP
A1  - Loeb, Horst Wolfgang
A1  - Schartner, Karl-Heinz
A1  - Dachwald, Bernd
A1  - Seboldt, Wolfgang
T1  - SEP-Sample return from a main belt asteroid
T2  - 30th International Electric Propulsion Conference
N2  - By DLR-contact, sample return missions to the large main-belt asteroid “19, Fortuna” have been studied. The mission scenario has been based on three ion thrusters of the RIT-22 model, which is presently under space qualification, and on solar arrays equipped with triple-junction GaAs solar cells. After having designed the spacecraft, the orbit-to-orbit trajectories for both, a one-way SEP mission with a chemical sample return and an all-SEP return mission, have been optimized using a combination of artificial neural networks with evolutionary algorithms. Additionally, body-to-body trajectories have been
investigated within a launch period between 2012 and 2015. For orbit-to-orbit calculation, the launch masses of the hybrid mission and of the all-SEP mission resulted in 2.05 tons and 1.56 tons, respectively, including a scientific payload of 246 kg. For the related transfer
durations 4.14 yrs and 4.62 yrs were obtained. Finally, a comparison between the mission scenarios based on SEP and on NEP have been carried out favouring clearly SEP.
Y1  - 2007
SP  - 1
EP  - 11
ER  - 
TY  - JOUR
A1  - Ley, Wilfried
A1  - Plescher, Engelbert
A1  - Scholz, Artur
A1  - Piepenbrock, Johannes
T1  - COMPASS-1 picosatellite project / Ley, Wilfried ; Plescher, Engelbert ; Scholz, Artur ; Piepenbrock, Johannes
JF  - Small satellites for earth observation : digest of the 6th International symposium of the International Academy of Astronautics, Berlin, April 23 - 26, 2007 / ed. by Rainer Sandau; Hans-Peter Röser; Arnoldo Valenzuela
Y1  - 2007
SN  - 9783896855718
N1  - Symposium on Small Satellites for Earth Observation ; (6, 2007, Berlin)
SP  - 147
EP  - 150
PB  - Wissenschaft und Technik Verl.
CY  - Berlin
ER  - 
TY  - CHAP
A1  - Kowalski, Julia
A1  - Bartelt, Perry
A1  - McElwaine, J.
T1  - Two-phase debris flow modeling
T2  - Geophysical Research Abstracts
Y1  - 2007
N1  - A-08119
ER  - 
TY  - JOUR
A1  - Henn, Gudrun
A1  - Polaczek, Christa
T1  - Studienerfolg in den Ingenieurwissenschaften
JF  - Das Hochschulwesen : HSW ; Forum für Hochschulforschung, -praxis und -politik
Y1  - 2007
SN  - 0018-2974
VL  - 55
IS  - 5
SP  - 144
EP  - 147
ER  - 
TY  - JOUR
A1  - Gerhardt, Hans Joachim
A1  - Schönwald, J.
A1  - Konrath, B.
T1  - Verwendung von Leichtgas bei Brandsimulationen - unzulässig oder sinnvoll?
JF  - VFDB-Zeitschrift : Forschung, Technik und Management im Brandschutz. 56 (2007), H. 1
Y1  - 2007
SN  - 0042-1804
SP  - 29
EP  - 31
ER  - 
TY  - JOUR
A1  - Funke, Harald
A1  - Robinson, A. E.
T1  - Development of a new test rig for a micro scale hydrogen combustion chamber
JF  - Proceedings of the 2nd European Conference for Aero-Space Sciences : July 1 - 6, 2007, Brussels, Belgium
Y1  - 2007
N1  - European Conference for Aerospace Sciences <2, 2007, Brüssel> ; EUCASS <2, 2007, Brüssel> ; Paper No. 22
SP  - 1
EP  - 8
PB  - -
ER  - 
TY  - BOOK
A1  - Esch, Thomas
T1  - Verbrennungstechnik. - 	6. Aufl., [Umdruck]. - (Angewandte Thermodynamik und Verbrennungstechnik)
Y1  - 2007
PB  - Fachhochschule Aachen, Lehr- und Forschungsgebiet Thermodynamik und Verbrennungstechnik
CY  - Aachen
ER  - 
TY  - BOOK
A1  - Esch, Thomas
T1  - Experimentelle Untersuchungen an Antriebssystemen von Kraft-, Luft- und Raumfahrzeugen : Vorlesungsumdruck. Bd. 1
Y1  - 2007
PB  - Fachhochschule Aachen, Lehr- und Forschungsgebiet Thermodynamik und Verbrennungstechnik
CY  - Aachen
ER  - 
TY  - BOOK
A1  - Esch, Thomas
T1  - Experimentelle Untersuchungen an Antriebssystemen von Kraft-, Luft- und Raumfahrzeugen : Vorlesungsumdruck. Bd. 2
Y1  - 2007
PB  - Fachhochschule Aachen, Lehr- und Forschungsgebiet Thermodynamik und Verbrennungstechnik
CY  - Aachen
ER  -