TY  - CHAP
A1  - Hülsen, Benjamin
A1  - Mulsow, Niklas A.
A1  - Dabrowski, Adam
A1  - Brinkmann, Wiebke
A1  - Gützlaff, Joel
A1  - Spies, Leon
A1  - Czupalla, Markus
A1  - Kirchner, Frank
T1  - Towards an autonomous micro rover with night survivability for lunar exploration
T2  - Proceedings of the 74th International Astronautical Congress
N2  - In Europe, efforts are underway to develop key technologies that can be used to explore the Moon and to exploit the resources available. This includes technologies for in-situ resource utilization (ISRU), facilitating the possibility of a future Moon Village. The Moon is the next step for humans and robots to exploit the use of available resources for longer term missions, but also for further exploration of the solar system. A challenge for effective exploration missions is to achieve a compact and lightweight robot to reduce launch costs and open up the possibility of secondary payload options. Current micro rover concepts are primarily designed to last for one day of solar illumination and show a low level of autonomy. Extending the lifetime of the system by enabling survival of the lunar night and implementing a high level of autonomy will significantly increase potential mission applications and the operational range. As a reference mission, the deployment of a micro rover in the equatorial region of the Moon is being considered. An overview of mission parameters and a detailed example mission sequence is given in this paper. The mission parameters are based on an in-depth study of current space agency roadmaps, scientific goals, and upcoming flight opportunities. Furthermore, concepts of the ongoing international micro rover developments are analyzed along with technology solutions identified for survival of lunar nights and a high system autonomy. The results provide a basis of a concise requirements set-up to allow dedicated system developments and qualification measures in the future.
Y1  - 2023
N1  - 74. International Astronautical Congress (IAC-2023), October 2-6 2023, Baku, Azerbaijan
PB  - dfki
ER  - 
TY  - JOUR
A1  - Esch, Thomas
T1  - Trends in commercial vehicle powertrains
JF  - ATZautotechnology
N2  - Low emission zones and truck bans, the rising price of diesel and increases in road tolls: all of these factors are putting serious pressure on the transport industry. Commercial vehicle manufacturers and their suppliers are in the process of identifying new solutions to these challenges as part of their efforts to meet the EEV (enhanced environmentally friendly vehicle) limits, which are currently the most robust European exhaust and emissions standards for trucks and buses.
KW  - European Transient Cycle
KW  - Common Rail Injection System
KW  - Commercial Vehicle
KW  - Selective Catalytic Reduction
KW  - Diesel Engine
Y1  - 2010
U6  - https://doi.org/10.1007/BF03247185
SN  - 2192-886X
VL  - 2010
IS  - 10
SP  - 26
EP  - 31
PB  - Vieweg & Sohn
CY  - Wiesbaden
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  - CHAP
A1  - Kowalski, Julia
A1  - McElwaine, J.
T1  - Two-phase debris flow modeling
T2  - Geophysical Research Abstracts
Y1  - 2008
N1  - A-01048
ER  - 
TY  - THES
A1  - Kowalski, Julia
T1  - Two-phase Modeling of Debris Flows
Y1  - 2008
SN  - 978-3-86664-524-0
N1  - Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 17827, 2008
PB  - Mensch und Buch
CY  - Berlin
ER  - 
TY  - JOUR
A1  - Wittmann, Klaus
A1  - Gillessen, F.
A1  - Otto, G.
A1  - Röstel, R.
T1  - Undercooling and solidification of metallic melts suspended in a non-nucleating matrix: Experiment NUCAL of the German Spacelab Mission D-2
JF  - Acta Astronautica. 38 (1996), H. 1
Y1  - 1996
SN  - 0094-5765
SP  - 63
EP  - 68
ER  - 
TY  - CHAP
A1  - Funke, Harald
A1  - Esch, Thomas
A1  - Roosen, Peter
ED  - Bartz, Wilfried J.
T1  - Using motor gasoline for aircrafts - coping with growing bio-fuel-caused risks by understanding cause-effect relationship
T2  - Fuels 2009 : mineral oil based and alternative fuels ; 7th international colloquium ; January 14 - 15, 2009
N2  - The utilisation of vehicle-oriented gasoline in general aviation is very desirable for both ecological and economical reasons, as well as for general considerations of availability. As of today vehicle fuels may be used if the respective engine and cell are certified for such an operation. For older planes a supplementary technical certificate is provided for gasoline mixtures with less than 1 % v/v ethanol only, though. Larger admixtures of ethanol may lead to sudden engine malfunction and should be considered as considerable security risks. Major problems are caused by the partially ethanol non-withstanding materials, a necessarily changed stochiometric adjustment of the engine for varying ethanol shares and the tendency for phase separation in the presence of absorbed water. The concepts of the flexible fuel vehicles are only partially applicable in the view of air security.
Y1  - 2009
SN  - 978-3-924813-75-8
SP  - 237
EP  - 244
PB  - Technische Akademie Esslingen (TAE)
CY  - Ostfildern
ER  - 
TY  - JOUR
A1  - Blome, Hans-Joachim
A1  - Priester, Wolfgang
T1  - Vacuum energy in cosmic dynamics
JF  - Astrophysics and Space Science. 117 (1985), H. 2
Y1  - 1985
SN  - 0004-640X
SP  - 327
EP  - 335
ER  - 
TY  - JOUR
A1  - German, Laura
A1  - Mikucki, Jill A.
A1  - Welch, Susan A.
A1  - Welch, Kathleen A.
A1  - Lutton, Anthony
A1  - Dachwald, Bernd
A1  - Kowalski, Julia
A1  - Heinen, Dirk
A1  - Feldmann, Marco
A1  - Francke, Gero
A1  - Espe, Clemens
A1  - Lyons, W. Berry
T1  - Validation of sampling antarctic subglacial hypersaline waters with an electrothermal ice melting probe (IceMole) for environmental analytical geochemistry
JF  - International Journal of Environmental Analytical Chemistry
N2  - Geochemical characterisation of hypersaline waters is difficult as high concentrations of salts hinder the analysis of constituents at low concentrations, such as trace metals, and the collection of samples for trace metal analysis in natural waters can be easily contaminated. This is particularly the case if samples are collected by non-conventional techniques such as those required for aquatic subglacial environments. In this paper we present the first analysis of a subglacial brine from Taylor Valley, (~ 78°S), Antarctica for the trace metals: Ba, Co, Mo, Rb, Sr, V, and U. Samples were collected englacially using an electrothermal melting probe called the IceMole. This probe uses differential heating of a copper head as well as the probe’s sidewalls and an ice screw at the melting head to move through glacier ice. Detailed blanks, meltwater, and subglacial brine samples were collected to evaluate the impact of the IceMole and the borehole pump, the melting and collection process, filtration, and storage on the geochemistry of the samples collected by this device. Comparisons between melt water profiles through the glacier ice and blank analysis, with published studies on ice geochemistry, suggest the potential for minor contributions of some species Rb, As, Co, Mn, Ni, NH4+, and NO2−+NO3− from the IceMole. The ability to conduct detailed chemical analyses of subglacial fluids collected with melting probes is critical for the future exploration of the hundreds of deep subglacial lakes in Antarctica.
Y1  - 2021
U6  - https://doi.org/10.1080/03067319.2019.1704750
SN  - 0306-7319
VL  - 101
IS  - 15
SP  - 2654
EP  - 2667
PB  - Taylor & Francis
CY  - London
ER  - 
TY  - JOUR
A1  - Heierli, Joachim
A1  - Purves, Ross S.
A1  - Felber, Andreas
A1  - Kowalski, Julia
T1  - Verification of nearest-neighbours interpretations in avalanche forecasting
JF  - Annals of Glaciology
N2  - This paper examines the positive and negative aspects of a range of interpretations of nearest-neighbours models. Measures-oriented and distributionoriented verification methods are applied to categorial, probabilistic and descriptive interpretations of nearest neighbours used operationally in avalanche forecasting in Scotland and Switzerland. The dependence of skill and accuracy measures on base rate is illustrated. The purpose of the forecast and the definition of events are important variables in determining the quality of the forecast. A discussion of the application of different interpretations in operational avalanche forecasting is presented.
KW  - avalanche
Y1  - 2004
SN  - 1727-5644
VL  - 38
IS  - 1
SP  - 84
EP  - 88
ER  - 
TY  - JOUR
A1  - Mathiak, Gerhard
A1  - Willnecker, Rainer
A1  - Plescher, Engelbert
T1  - Vibrational effects on diffusion experiments
JF  - Microgravity science and technology : international journal for microgravity research and applications
Y1  - 2005
SN  - 0938-0108
VL  - Vol. 15
IS  - No. 1
SP  - 295
EP  - 300
ER  - 
TY  - CHAP
A1  - Baader, Fabian
A1  - Reiswich, M.
A1  - Bartsch, M.
A1  - Keller, D.
A1  - Tiede, E.
A1  - Keck, G.
A1  - Demircian, A.
A1  - Friedrich, M.
A1  - Dachwald, Bernd
A1  - Schüller, K.
A1  - Lehmann, R.
A1  - Chojetzki, R.
A1  - Durand, C.
A1  - Rapp, L.
A1  - Kowalski, Julia
A1  - Förstner, R.
T1  - VIPER - Student research on extraterrestrical ice penetration technology
T2  - Proceedings of the 2nd Symposium on Space Educational Activities
N2  - Recent analysis of scientific data from Cassini and earth-based observations gave evidence for a global ocean under a surrounding solid ice shell on Saturn's moon Enceladus. Images of Enceladus' South Pole showed several fissures in the ice shell with plumes constantly exhausting frozen water particles, building up the E-Ring, one of the outer rings of Saturn. In this southern region of Enceladus, the ice shell is considered to be as thin as 2 km, about an order of magnitude thinner than on the rest of the moon. Under the ice shell, there is a global ocean consisting of liquid water. Scientists are discussing different approaches the possibilities of taking samples of water, i.e. by melting through the ice using a melting probe. FH Aachen UAS developed a prototype of maneuverable melting probe which can navigate through the ice that has already been tested successfully in a terrestrial environment. This means no atmosphere and or ambient pressure, low ice temperatures of around 100 to 150K (near the South Pole) and a very low gravity of 0,114 m/s^2 or 1100 μg. Two of these influencing measures are about to be investigated at FH Aachen UAS in 2017, low ice temperature and low ambient pressure below the triple point of water. Low gravity cannot be easily simulated inside a large experiment chamber, though. Numerical simulations of the melting process at RWTH Aachen however are showing a gravity dependence of melting behavior. Considering this aspect, VIPER provides a link between large-scale experimental simulations at FH Aachen UAS and numerical simulations at RWTH Aachen. To analyze the melting process, about 90 seconds of experiment time in reduced gravity and low ambient pressure is provided by the REXUS rocket. In this time frame, the melting speed and contact force between ice and probes are measured, as well as heating power and a two-dimensional array of ice temperatures. Additionally, visual and infrared cameras are used to observe the melting process.
Y1  - 2018
SP  - 1
EP  - 6
ER  - 
TY  - JOUR
A1  - Schirra, Julian
A1  - Bissonnette, William
A1  - Bramesfeld, Götz
T1  - Wake-model effects on induced drag prediction of staggered boxwings
JF  - Aerospace
Y1  - 2018
U6  - https://doi.org/10.3390/aerospace5010014
SN  - 2226-4310
VL  - 5
IS  - 1
ER  - 
TY  - JOUR
A1  - Schmitz, Günter
A1  - Schmitt, H.J.
A1  - Dammann, H.
T1  - Weakly Guiding Semileaky Isolator with a Form-Birefringent Top Layer
JF  - Conference on Lasers and Electro-Optics ; (5, 1985, Baltimore, Md.) ; Conference on Lasers and Electro-Optics (CLEO '85) ; (1985.05.21-24 ; Baltimore, Md.)
Y1  - 1985
SP  - 260
PB  - Optical Society of America
CY  - Washington, DC
ER  - 
TY  - JOUR
A1  - Götten, Falk
A1  - Havermann, Marc
A1  - Braun, Carsten
A1  - Marino, Matthew
A1  - Bil, Cees
T1  - Wind-tunnel and CFD investigations of UAV landing gears and turrets – Improvements in empirical drag estimation
JF  - Aerospace Science and Technology
N2  - This paper analyzes the drag characteristics of several landing gear and turret configurations that are representative of unmanned aircraft tricycle landing gears and sensor turrets. A variety of these components were constructed via 3D-printing and analyzed in a wind-tunnel measurement campaign. Both turrets and landing gears were attached to a modular fuselage that supported both isolated components and multiple components at a time. Selected cases were numerically investigated with a Reynolds-averaged Navier-Stokes approach that showed good accuracy when compared to wind-tunnel data. The drag of main gear struts could be significantly reduced via streamlining their cross-sectional shape and keeping load carrying capabilities similar. The attachment of wheels introduced interference effects that increased strut drag moderately but significantly increased wheel drag compared to isolated cases. Very similar behavior was identified for front landing gears. The drag of an electro-optical and infrared sensor turret was found to be much higher than compared to available data of a clean hemisphere-cylinder combination. This turret drag was merely influenced by geometrical features like sensor surfaces and the rotational mechanism. The new data of this study is used to develop simple drag estimation recommendations for main and front landing gear struts and wheels as well as sensor turrets. These recommendations take geometrical considerations and interference effects into account.
Y1  - 2020
U6  - https://doi.org/10.1016/j.ast.2020.106306
SN  - 1270-9638
VL  - 107
IS  - Art. 106306
PB  - Elsevier
CY  - Amsterdam
ER  - 
TY  - JOUR
A1  - Hoeveler, B.
A1  - Bauknecht, André
A1  - Wolf, C. Christian
A1  - Janser, Frank
T1  - Wind-Tunnel Study of a Wing-Embedded Lifting Fan Remaining Open in Cruise Flight
JF  - Journal of Aircraft
N2  - It is investigated whether a nonrotating lifting fan remaining uncovered during cruise flight, as opposed to being covered by a shutter system, can be realized with limited additional drag and loss of lift during cruise flight. A wind-tunnel study of a wing-embedded lifting fan has been conducted at the Side Wind Test Facility Göttingen of DLR, German Aerospace Center in Göttingen using force, pressure, and stereoscopic particle image velocimetry techniques. The study showed that a step on the lower side of the wing in front of the lifting fan duct increases the lift-to-drag ratio of the whole model by up to 25% for all positive angles of attack. Different sizes and inclinations of the step had limited influence on the surface pressure distribution. The data indicate that these parameters can be optimized to maximize the lift-to-drag ratio. A doubling of the curvature radius of the lifting fan duct inlet lip on the upper side of the wing affected the lift-to-drag ratio by less than 1%. The lifting fan duct inlet curvature can therefore be optimized to maximize the vertical fan thrust of the rotating lifting fan during hovering without affecting the cruise flight performance with a nonrotating fan.
Y1  - 2020
U6  - https://doi.org/10.2514/1.C035422
SN  - 1533-3868
VL  - 57
IS  - 4
PB  - AIAA
CY  - Reston, Va.
ER  - 
TY  - CHAP
A1  - Spohr, A.
A1  - Schirra, Julian
A1  - Hoefling, J.
A1  - Schedl, A.
T1  - Wing weight estimation methodology for highly non-planar lifting systems during conceptual design
T2  - Deutscher Luft- und Raumfahrtkongress 2013 : 10.9. - 12.9.2013, Stuttgart
Y1  - 2013
SP  - Publ. online
ER  - 
TY  - JOUR
A1  - Overduin, James
A1  - Blome, Hans-Joachim
A1  - Hoell, Josef
T1  - Wolfgang Priester: from the big bounce to the Lambda-dominated universe
JF  - Naturwissenschaften
Y1  - 2007
SN  - 0028-1042
VL  - 94
IS  - 6
SP  - 417
EP  - 429
ER  -