@inproceedings{DachwaldWurm2009, author = {Dachwald, Bernd and Wurm, P.}, title = {Mission analysis for an advanced solar photon thruster}, series = {60th International Astronautical Congress 2009, IAC 2009}, volume = {Vol. 8}, booktitle = {60th International Astronautical Congress 2009, IAC 2009}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {978-161567908-9}, pages = {6838 -- 6851}, year = {2009}, abstract = {The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), is a solar sail design concept, for which the two basic functions of the solar sail, namely light collection and thrust direction, are uncoupled. In this paper, we introduce a novel SPT concept, termed the Advanced Solar Photon Thruster (ASPT). This model does not suffer from the simplified assumptions that have been made for the analysis of compound solar sails in previous studies. We present the equations that describe the force, which acts on the ASPT. After a detailed design analysis, the performance of the ASPT with respect to the conventional flat solar sail (FSS) is investigated for three interplanetary mission scenarios: An Earth-Venus rendezvous, where the solar sail has to spiral towards the Sun, an Earth-Mars rendezvous, where the solar sail has to spiral away from the Sun, and an Earth-NEA rendezvous (to near-Earth asteroid 1996FG3), where a large orbital eccentricity change is required. The investigated solar sails have realistic near-term characteristic accelerations between 0.1 and 0.2mm/s2. Our results show that a SPT is not superior to the flat solar sail unless very idealistic assumptions are made.}, language = {en} } @inproceedings{DachwaldWurm2009, author = {Dachwald, Bernd and Wurm, P.}, title = {Design concept and modeling of an advanced solar photon thruster}, series = {Advances in the Astronautical Sciences}, booktitle = {Advances in the Astronautical Sciences}, publisher = {American Astronautical Society}, address = {San Diego, Calif.}, isbn = {978-087703554-1}, issn = {00653438}, pages = {723 -- 740}, year = {2009}, abstract = {The so-called "compound solar sail", also known as "Solar Photon Thruster" (SPT), holds the potential of providing significant performance advantages over the flat solar sail. Previous SPT design concepts, however, do not consider shadowing effects and multiple reflections of highly concentrated solar radiation that would inevitably destroy the gossamer sail film. In this paper, we propose a novel advanced SPT (ASPT) design concept that does not suffer from these oversimplifications. We present the equations that describe the thrust force acting on such a sail system and compare its performance with respect to the conventional flat solar sail.}, language = {en} } @inproceedings{GehlerOberBloebaumDachwald2009, author = {Gehler, M. and Ober-Bl{\"o}baum, S. and Dachwald, Bernd}, title = {Application of discrete mechanics and optimal control to spacecraft in non-keplerian motion around small solar system bodies}, series = {Procceedings of the 60th International Astronautical Congress}, booktitle = {Procceedings of the 60th International Astronautical Congress}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {978-161567908-9}, pages = {1360 -- 1371}, year = {2009}, abstract = {Prolonged operations close to small solar system bodies require a sophisticated control logic to minimize propellant mass and maximize operational efficiency. A control logic based on Discrete Mechanics and Optimal Control (DMOC) is proposed and applied to both conventionally propelled and solar sail spacecraft operating at an arbitrarily shaped asteroid in the class of Itokawa. As an example, stand-off inertial hovering is considered, recently identified as a challenging part of the Marco Polo mission. The approach is easily extended to stand-off orbits. We show that DMOC is applicable to spacecraft control at small objects, in particular with regard to the fact that the changes in gravity are exploited by the algorithm to optimally control the spacecraft position. Furthermore, we provide some remarks on promising developments.}, language = {en} } @article{FrauenrathHezelHeinrichsetal.2009, author = {Frauenrath, Tobias and Hezel, Fabian and Heinrichs, Uwe and Kozerke, Sebastian and Utting, Jane and Kob, Malte and Butenweg, Christoph and Boesiger, Peter and Niendorf, Thoralf}, title = {Feasibility of Cardiac Gating Free of Interference With Electro-Magnetic Fields at 1.5 Tesla, 3.0 Tesla and 7.0 Tesla Using an MR-Stethoscope}, series = {Investigative Radiology}, volume = {44}, journal = {Investigative Radiology}, number = {9}, publisher = {Lippincott Williams \& Wilkins ; (via Ovid)}, address = {Philadelphia, Pa}, issn = {1536-0210 (online)}, doi = {10.1097/RLI.0b013e3181b4c15e}, pages = {539 -- 547}, year = {2009}, language = {en} } @inproceedings{KemperHellenbroichEsch2009, author = {Kemper, Hans and Hellenbroich, Gereon and Esch, Thomas}, title = {Concept of an innovative passenger-car hybrid drive for European driving conditions}, series = {Hybrid vehicles and energy management : 6th symposium ; 18th and 19th February 2009, Stadthalle Braunschweig}, booktitle = {Hybrid vehicles and energy management : 6th symposium ; 18th and 19th February 2009, Stadthalle Braunschweig}, publisher = {Gesamtzentrum f{\"u}r Verkehr (GZVB)}, address = {Braunschweig}, isbn = {978-3-937655-20-8}, pages = {264 -- 287}, year = {2009}, abstract = {The downsizing of spark ignition engines in conjunction with turbocharging is considered to be a promising method for reducing CO₂ emissions. Using this concept, FEV has developed a new, highly efficient drivetrain to demonstrate fuel consumption reduction and drivability in a vehicle based on the Ford Focus ST. The newly designed 1.8L turbocharged gasoline engine incorporates infinitely variable intake and outlet control timing and direct fuel injection utilizing piezo injectors centrally located. In addition, this engine uses a prototype FEV engine control system, with software that was developed and adapted entirely by FEV. The vehicle features a 160 kW engine with a maximum mean effective pressure of 22.4 bar and 34 \% savings in simulated fuel consumption. During the first stage, a new electrohydraulically actuated hybrid transmission with seven forward gears and one reverse gear and a single dry starting clutch will be integrated. The electric motor of the hybrid is directly connected to the gear set of the transmission. Utilizing the special gear set layout, the electric motor can provide boost during a change of gears, so that there is no interruption in traction. Therefore, the transmission system combines the advantages of a double clutch controlled gear change (gear change without an interruption in traction) with the efficient, cost-effective design of an automated manual transmission system. Additionally, the transmission provides a purely electric drive system and the operation of an air-conditioning compressor during the engine stop phases. One other alternative is through the use of CAI (Controlled Auto Ignition), which incorporates a process developed by FEV for controlled compression ignition.}, language = {en} } @inproceedings{FunkeEschRoosen2009, author = {Funke, Harald and Esch, Thomas and Roosen, Peter}, title = {Using motor gasoline for aircrafts - coping with growing bio-fuel-caused risks by understanding cause-effect relationship}, series = {Fuels 2009 : mineral oil based and alternative fuels ; 7th international colloquium ; January 14 - 15, 2009}, booktitle = {Fuels 2009 : mineral oil based and alternative fuels ; 7th international colloquium ; January 14 - 15, 2009}, editor = {Bartz, Wilfried J.}, publisher = {Technische Akademie Esslingen (TAE)}, address = {Ostfildern}, isbn = {978-3-924813-75-8}, pages = {237 -- 244}, year = {2009}, abstract = {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.}, language = {en} } @misc{ButenwegGellertReindletal.2009, author = {Butenweg, Christoph and Gellert, Christoph and Reindl, Lukas and Meskouris, Konstantin}, title = {A nonlinear method for the seismic safety verification of masonry buildings}, publisher = {National Technical University of Athens}, address = {Athen}, year = {2009}, abstract = {In order for traditional masonry to stay a competitive building material in seismically active regions there is an urgent demand for modern, deformation-based verification procedures which exploit the nonlinear load bearing reserves. The Capacity Spectrum Method (CSM) is a widely accepted design approach in the field of reinforced concrete and steel construction. It compares the seismic action with the load-bearing capacity of the building considering nonlinear material behavior with its post-peak capacity. The bearing capacity of the building is calculated iteratively using single wall capacity curves. This paper presents a new approach for the bilinear approximation of single wall capacity curves in the style of EC6/EC8 respectively FEMA 306/FEMA 356 based on recent shear wall test results of the European Collective-Research Project "ESECMaSE". The application of the CSM to masonry structures by using bilinear approximations of capacity curves as input is demonstrated on the example of a typical German residential home.}, language = {en} } @inproceedings{CzarneckiHeuserSpiliopoulou2009, author = {Czarnecki, Christian and Heuser, Marcus and Spiliopoulou, Myra}, title = {How does the implementation of a next generation network influence a telecommunication company?}, series = {European and Mediterranean Conference on Information Systems}, booktitle = {European and Mediterranean Conference on Information Systems}, editor = {Irani, Zahir}, publisher = {Brunel University}, address = {London}, isbn = {9781902316697}, pages = {1 -- 11}, year = {2009}, abstract = {As the potential of a Next Generation Network (NGN) is recognized, telecommunication companies consider switching to it. Although the implementation of an NGN seems to be merely a modification of the network infrastructure, it may trigger or require changes in the whole company and even influence the company strategy. To capture the effects of NGN we propose a framework based on concepts of business engineering and technical recommendations for the introduction of NGN technology. The specific design of solutions for the layers "Strategy", "Processes" and "Information Systems" as well as their interdependencies are an essential characteristic of the developed framework. We have per-formed a case study on NGN implementation and observed that all layers captured by our framework are influenced by the introduction of an NGN.}, language = {en} } @techreport{Buedenbender2009, type = {Working Paper}, author = {B{\"u}denbender, Martin}, title = {Atomausstieg in Deutschland - ein zukunftsf{\"a}higer Sonderweg im europ{\"a}ischen Kontext?}, series = {Arbeitspapiere des Instituts f{\"u}r Genossenschaftswesen der Westf{\"a}lischen Wilhelms-Universit{\"a}t M{\"u}nster, Nr. 90}, journal = {Arbeitspapiere des Instituts f{\"u}r Genossenschaftswesen der Westf{\"a}lischen Wilhelms-Universit{\"a}t M{\"u}nster, Nr. 90}, pages = {41}, year = {2009}, language = {de} } @article{BuedenbenderJanssenWobben2009, author = {B{\"u}denbender, Martin and Janssen, Matthias and Wobben, Magnus}, title = {Versorgungssicherheit auf Elektrizit{\"a}tsm{\"a}rkten — Investitionsdilemma durch ineffizientes Marktdesign?}, series = {Zeitschrift f{\"u}r Energiewirtschaft}, volume = {33}, journal = {Zeitschrift f{\"u}r Energiewirtschaft}, number = {1}, issn = {1866-2765}, pages = {49 -- 61}, year = {2009}, abstract = {Dieser Artikel befasst sich mit dem Investitionsdilemma in der Stromerzeugung, welches in unzureichend ausgestalteten liberalisierten Stromm{\"a}rkten zu einem gesamtwirtschaftlich unerw{\"u}nscht geringen Niveau an Versorgungssicherheit f{\"u}hrt. Die origin{\"a}ren Ursachen im deutschen Strommarkt liegen in einer eingeschr{\"a}nkten Schadenersatzpflicht der Lieferanten im Falle eines kapazit{\"a}tsbedingten Stromausfalls und in der zeitlichen Differenz zwischen letzter Handelsm{\"o}glichkeit und Lieferung. Letzteres verhindert ein jederzeitiges individuelles Glattstellen von unerwartet auftretenden Ein- bzw. Ausspeise{\"a}nderungen. Des Weiteren f{\"u}hren Faktoren wie die fehlende Partizipation der Endverbraucher am Großhandelsmarkt, die nur undifferenziert m{\"o}gliche Abschaltung von Endverbrauchern oder time lags durch lange Bau- und Genehmigungszeiten von Erzeugungskapazit{\"a}ten in Verbindung mit {\"u}ber lange Zeitr{\"a}ume nicht versicherbaren Risiken bez{\"u}glich Brennstoff-, CO2-Zertifikate- und Strompreisen zu einer Versch{\"a}rfung der Problematik. Sinnvolle L{\"o}sungsans{\"a}tze sind zum einen die Erh{\"o}hung der Intraday-Handelsliquidit{\"a}t zur Verbesserung der Marktr{\"a}umungsfunktion bis m{\"o}glichst kurz vor Stromlieferung, was z. B. durch eine F{\"o}rderung der Direktvermarktung Erneuerbarer Energien erreicht werden kann. Zum anderen tr{\"a}gt ein verst{\"a}rkter Ausbau von smart metern bei Endverbrauchern zu einer h{\"o}heren Versorgungssicherheit bei, da dies die Gl{\"a}ttung von Lastspitzen und die Artikulation der tats{\"a}chlichen Zahlungsbereitschaft von Endverbrauchern am Großhandelsmarkt erm{\"o}glicht.}, language = {de} } @article{Buedenbender2009, author = {B{\"u}denbender, Martin}, title = {Der Atomausstieg in Deutschland - ein zukunftsf{\"a}higer Sonderweg im europ{\"a}ischen Kontext?}, series = {atw International Journal for Nuclear Power}, volume = {54}, journal = {atw International Journal for Nuclear Power}, number = {10}, publisher = {Inforum}, address = {Berlin}, issn = {14315254}, pages = {616 -- 627}, year = {2009}, language = {de} } @article{Buedenbender2009, author = {B{\"u}denbender, Martin}, title = {Auswirkungen der europ{\"a}ischen Energiepolitik auf den deutschen Atomausstieg}, series = {Zeitschrift f{\"u}r Energiewirtschaft}, volume = {33}, journal = {Zeitschrift f{\"u}r Energiewirtschaft}, number = {4}, publisher = {Vieweg}, address = {Wiesbaden}, isbn = {1866-2765}, doi = {10.1007/s12398-009-0039-4}, pages = {341 -- 350}, year = {2009}, abstract = {Nach der Bundestagswahl am 27. September 2009 steht der Atomausstieg in Deutschland wieder ganz oben auf der politischen Agenda. Eine aktuelle Bestandsaufnahme aller ma\geblichen Argumente erscheint somit zwingend notwendig. Dabei sollte der Blickwinkel nicht national beschr{\"a}nkt bleiben, sondern vor allem der Einfluss der europ{\"a}ischen Dimension dieser Thematik miteinbezogen werden. Auf europ{\"a}ischer Ebene zeigt sich eine Position zu Gunsten der Kernenergie. Unter den 27 EU-Staaten findet gerade eine Renaissance der Atomkraft statt. Die drei europ{\"a}ischen Organe bef{\"u}rworten den umfangreichen Einsatz der Kernenergie als langfristigen Bestandteil des Energietr{\"a}germix. Deutschland geh{\"o}rt mit seinem Beschluss zum Atomausstieg einer Minderheit an. Als Teil eines immer st{\"a}rker zusammen wachsenden und letztendlich vollst{\"a}ndig integrierten europ{\"a}ischen Strommarktes wird Deutschland langfristig stets mit Atomstrom versorgt werden. Dies gilt losgel{\"o}st von dem Einsatz von Kernkraftwerken im Inland. Eine Abschaltung der Anlagen f{\"u}hrt damit nicht zur Zielerreichung der Atomkraftgegner, sondern lediglich zu zus{\"a}tzlichen energietechnischen Herausforderungen bei der Sicherstellung der deutschen Stromversorgung. Der deutsche Atomausstieg sollte aus diesem Grund von der neuen Bundesregierung zur{\"u}ck genommen werden.}, language = {de} } @book{Buedenbender2009, author = {B{\"u}denbender, Martin}, title = {Auswirkungen des europ{\"a}ischen CO2-Handelssystems auf Stromerzeugungsinvestitionen - m{\"o}gliche Ausgestaltung des Systems ab 2013}, series = {D{\"u}sseldorfer Schriften zum Energie- und Kartellrecht ; Bd. 13}, journal = {D{\"u}sseldorfer Schriften zum Energie- und Kartellrecht ; Bd. 13}, publisher = {etv Energieverlag}, address = {Essen}, isbn = {9783942370318}, pages = {140 S. : graph. Darst.}, year = {2009}, abstract = {Zahlreiche Einflussfaktoren haben in den vergangenen Jahren das Gesicht der Elektrizit{\"a}tsm{\"a}rkte stark ver{\"a}ndert. Hierzu z{\"a}hlen vor allem die Einf{\"u}hrung der {\"o}konomischen Gesetze des Wettbewerbsmarktes durch die Liberalisierung sowie die nun kostenpflichtige Ber{\"u}cksichtigung des bei der Stromerzeugung hervorgerufenen CO2-Ausstoßes durch die Einf{\"u}hrung des europ{\"a}ischen Emissionshandelssystems (EUTS). Die Folgen dieses Ver{\"a}nderungsprozesses lassen sich auf Grund der langen Investitionszyklen im Kraftwerksbau bisher nur unvollst{\"a}ndig {\"u}berblicken. Dies ist insbesondere im Hinblick auf die Versorgungssicherheit als Teil des energiewirtschaftlichen Zieldreiecks des \S 1 EnWG von großer Bedeutung. Dazu z{\"a}hlt insbesondere, ob die Versorgungssicherheit in Deutschland bei gegenw{\"a}rtigem Marktdesign auch dauerhaft gew{\"a}hrleistet sein wird. Es stellt sich heraus, dass es im Bereich der Spitzenlastkraftwerke zu Investitionen in gesamtwirtschaftlich zu geringen Umfang kommen kann. Dieses Investitionsdilemma beruht auf einem externen Effekt, der durch die aktuelle Ausgestaltung des deutschen Schadenersatzrechtes entsteht. Hierdurch ist die sichere Stromversorgung in Zeiten hoher Last potenziell gef{\"a}hrdet. Um die Wirkungen des Investitionsdilemmas abzumildern oder ganz zu beseitigen sind verschiedene Investitionsanreize durch entsprechende Ausgestaltung des EUTS denkbar. Diese werden im Einzelnen analysiert.}, language = {de} } @inproceedings{SpurmannOhndorfDachwaldetal.2009, author = {Spurmann, J{\"o}rn and Ohndorf, Andreas and Dachwald, Bernd and Seboldt, Wolfgang and L{\"o}b, Horst and Schartner, Karl-Heinz}, title = {Interplanetary trajectory optimization for a sep mission to Saturn}, series = {60th International Astronautical Congress 2009}, booktitle = {60th International Astronautical Congress 2009}, isbn = {9781615679089}, pages = {5234 -- 5248}, year = {2009}, abstract = {The recently proposed NASA and ESA missions to Saturn and Jupiter pose difficult tasks to mission designers because chemical propulsion scenarios are not capable of transferring heavy spacecraft into the outer solar system without the use of gravity assists. Thus our developed mission scenario based on the joint NASA/ESA Titan Saturn System Mission baselines solar electric propulsion to improve mission flexibility and transfer time. For the calculation of near-globally optimal low-thrust trajectories, we have used a method called Evolutionary Neurocontrol, which is implemented in the low-thrust trajectory optimization software InTrance. The studied solar electric propulsion scenario covers trajectory optimization of the interplanetary transfer including variations of the spacecraft's thrust level, the thrust unit's specific impulse and the solar power generator power level. Additionally developed software extensions enabled trajectory optimization with launcher-provided hyperbolic excess energy, a complex solar power generator model and a variable specific impulse ion engine model. For the investigated mission scenario, Evolutionary Neurocontrol yields good optimization results, which also hold valid for the more elaborate spacecraft models. Compared to Cassini/Huygens, the best found solutions have faster transfer times and a higher mission flexibility in general.}, language = {en} } @inproceedings{SchartnerLoebDachwaldetal.2009, author = {Schartner, Karl-Heinz and Loeb, H. W. and Dachwald, Bernd and Ohndorf, Andreas}, title = {Perspectives of electric propulsion for outer planetary and deep space missions}, series = {European Planetary Science Congress 2009}, booktitle = {European Planetary Science Congress 2009}, pages = {416 -- 416}, year = {2009}, abstract = {Solar-electric propulsion (SEP) is superior with respect to payload capacity, flight time and flexible launch window to the conventional interplanetary transfer method using chemical propulsion combined with gravity assists. This fact results from the large exhaust velocities of electric low-thrust propulsion and is favourable also for missions to the giant planets, Kuiper-belt objects and even for a heliopause probe (IHP) as shown in three studies by the authors funded by DLR. They dealt with a lander for Europa and a sample return mission from a mainbelt asteroid [1], with the TANDEM mission [2]; the third recent one investigates electric propulsion for the transfer to the edge of the solar system. All studies are based on triple-junction solar arrays, on rf-ion thrusters of the qualified RIT-22 type and they use the intelligent trajectory optimization program InTrance [3].}, language = {en} } @article{GrajewskiKoesterTurek2009, author = {Grajewski, Matthias and K{\"o}ster, Michael and Turek, Stefan}, title = {Mathematical and Numerical Analysis of a Robust and Efficient Grid Deformation Method in the Finite Element Context}, series = {SIAM Journal on Scientific Computing}, volume = {31}, journal = {SIAM Journal on Scientific Computing}, number = {2}, publisher = {Society for Industrial and Applied Mathematics}, address = {Philadelphia, Pa.}, doi = {10.1137/050639387}, pages = {1539 -- 1557}, year = {2009}, language = {en} } @inproceedings{KarzerMatcha2009, author = {Karzer, R{\"u}diger and Matcha, Heike}, title = {Experimental design-build: teaching parameter-based design}, series = {Computation: The New Realm of Architectural Design [27th eCAADe Conference Proceedings]}, booktitle = {Computation: The New Realm of Architectural Design [27th eCAADe Conference Proceedings]}, isbn = {978-0-9541183-8-9}, doi = {10.52842/conf.ecaade.2009.153}, pages = {153 -- 158}, year = {2009}, language = {en} } @inproceedings{MatchaQuasten2009, author = {Matcha, Heike and Quasten, Gero}, title = {A Parametric-Typological Tool: More Diversity for Mass Produced Single Family Homes Through Parametrized Design and Customized Mass Production}, series = {Computation: The New Realm of Architectural Design [27th eCAADe Conference Proceedings}, booktitle = {Computation: The New Realm of Architectural Design [27th eCAADe Conference Proceedings}, isbn = {978-0-9541183-8-9}, pages = {409 -- 416}, year = {2009}, language = {en} } @book{Matcha2009, author = {Matcha, Heike}, title = {Expo 15 : Experimental Parametric Object ; Realisierung des Messestandes "M{\"o}biusband" f{\"u}r den Fachbereich Architektur der Technischen Universit{\"a}t Darmstadt}, publisher = {Technische Universit{\"a}t Darmstadt}, address = {Darmstadt}, pages = {56 S. : Ill.}, year = {2009}, language = {de} } @incollection{MatchaBarczikAgkathidis2009, author = {Matcha, Heike and Barczik, G{\"u}nter and Agkathidis, Asterios}, title = {Produktive Prozesse: Mehr Vielfalt, Komplexit{\"a}t und Kreativit{\"a}t im Entwerfen mittels parametrisierter generativer Algorithmen}, series = {Modulare Strukturen in Entwurf und Architektur}, booktitle = {Modulare Strukturen in Entwurf und Architektur}, publisher = {BIS-Publishers}, address = {Amsterdam}, isbn = {978-90-6369-208-7}, pages = {126 -- 130}, year = {2009}, language = {de} }