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Within ESA's Cosmic Vision 2015-2025 plan, a mission to explore the Saturnian System, with special emphasis on its two moons Titan and Enceladus, was selected for study, termed TANDEM (Titan and Enceladus Mission). In this paper, we describe an optimized mission design for a TANDEM-derived solar electric propulsion (SEP) mission. We have chosen the SEP mission scenario for the interplanetary transfer of the TANDEM spacecraft because all feasible gravity assist sequences for a chemical transfer between 2015 and 2025 result in long flight times of about nine years. Our SEP system is based on the German RIT ion engine. For our optimized mission design, we have extensively explored the SEP parameter space (specific impulse, thrust level, power level) and have calculated an optimal interplanetary trajectory for each setting. In contrast to the original TANDEM mission concept, which intends to use two launch vehicles and an all-chemical transfer, our SEP mission design requires only a single Ariane 5 ECA launch for the same payload mass. Without gravity assist, it yields a faster and more flexible transfer with a fight time of less than seven years, and an increased payload ratio. Our mission design proves thereby the capability of SEP even for missions into the outer solar system.
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.
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.
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.
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.
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.
How does the implementation of a next generation network influence a telecommunication company?
(2009)
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.
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.
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].
Konvergenz von drahtlosen und drahtgebundenen Kommunikationstechnologien in der Gebäudeautomation
(2009)
Blended Shopping
(2009)
Physical layer specification of the L-band Digital Aeronautical Communications System (L-DACS1)
(2009)
Optimierung des potentiellen Sauerstoffeintrags auf Treppenschussrinnen mit gemäßigter Neigung
(2009)
Kraft-Wärme-Kälte-Kopplung im Leistungsbereich in 10kW mit periodisch arbeitender Sorptionsmaschine
(2009)
A melting probe equipped with autofluorescence-based detection system combined with a light scattering unit, and, optionally, with a microarray chip would be ideally suited to probe icy environments like Europa’s ice layer as well as the polar ice layers of Earth and Mars for recent and extinct live.
As a deduction from these results, we can conclude that proteins mainly in vitro, denaturate totally at a temperature between 57°C -62°C, and they also affected by NO and different ions types. In which mainly, NO cause earlier protein denaturation, which means that, NO has a destabilizing effect on proteins, and also different ions will alter the protein denaturation in which, some ions will cause earlier protein denaturation while others not.
The absence of a general method for endotoxin removal from liquid interfaces gives an opportunity to find new methods and materials to overcome this gap. Activated nanostructured carbon is a promising material that showed good adsorption properties due to its vast pore network and high surface area. The aim of this study is to find the adsorption rates for a carboneous material produced at different temperatures, as well as to reveal possible differences between the performance of the material for each of the adsorbates used during the study (hemoglobin, serum albumin and lipopolysaccharide, LPS).
One of interesting but not well known water properties is related to appearance of highly ordered structures in response to strong electrical field. In 1893 Sir William Armstrong placed a cotton thread between two wine glasses filled with chemically pure water. When high DC voltage was applied between the glasses, a connection consisting of water formed, producing a "water bridge"
Working paper distributed at 2nd Annual Next Generation Telecommunications Conference 2009, 13th – 14th October 2009, Brussels 14 pages Abstract Governments all over Europe are in the process of adopting new broadband strategies. The objective is to create modern telecommunications networks based on powerful broadband infrastructures". In doing so, they aim for innovative and investment-friendly concepts. For instance, in a recently published consultation paper on the subject the German regulator BNetzA declared that it will take “greater account of … reducing risks, securing the investment and innovation power, providing planning certainty and transparency – in order to support and advance broadband rollout in Germany”. It further states that when regulating wholesale rates it has to be ensured that “… adequate incentives for network rollout are provided on the one hand, while sustainable and fair competition is ensured on the other”. Also an EC draft recommendation on regulated network access is about to set new standards for the regulation of next generation access networks. According to the recommendation the prices of new assets shall be based on costs plus a projectspecific risk premium to be included in the costs of capital for the investment risk incurred by the operator. This approach has been criticised from various sides. In particular it has been questioned whether such an approach is adequate to meet the objectives of encouraging both competition and investment into next generation access networks. Against this background, the concept of “long term risk sharing contracts” has been proposed recently as an approach which does not only incorporate the various additional risks involved in the deployment of NGA infrastructure, but has several other advantages. This paper will demonstrate that the concept allows for competition to evolve at both the retail and wholesale level on fair, objective, non-discriminatory and transparent terms and conditions. Moreover, it ensures the highest possible investment incentive in line with socially desirable outcome. The paper is organised as follows: The next section will briefly outline the importance of encouraging competition and investment in an NGA-environment. The third section will specify the design of long term risk sharing contracts in view of achieving these objectives. The fourth section will examine potential problems associated with the concept. In doing so a way of how to deal with them will be elaborated. The last section will look at arguments against long term risk sharing contracts. It will be shown that these arguments are not strong enough to build a case against introducing such contracts.
The ANM’09 multi-disciplinary scientific program includes topics in the fields of "Nanotechnology and Microelectronics" ranging from "Bio/Micro/Nano Materials and Interfacing" aspects, "Chemical and Bio-Sensors", "Magnetic and Superconducting Devices", "MEMS and Microfluidics" over "Theoretical Aspects, Methods and Modelling" up to the important bridging "Academics meet Industry".
8. VDE/ABB-Blitzschutztagung, 29. - 30. Oktober 2009 in Neu-Ulm. Blitzschutztagung <8, 2009, Neu-Ulm> Berlin : VDE Verl. 2009 Großkraftwerke können durch Blitzentladungen mit potentiellen Auswirkungen auf deren Verfügbarkeit und Sicherheit gefährdet werden. Ein sehr spezielles Szenario, welches aus aktuellem Anlass zu untersuchen war, betrifft den kraftwerksnahen Blitzeinschlag in die Hochspannungs-Freileitung am Netzanschluss der Anlage. Wird nun noch ein sogenannter Schirmfehler unterstellt, d.h. der direkte Blitzeinschlag erfolgt in ein Leiterseil des Hoch- bzw. Höchstspannungsnetzes und nicht in das darüber gespannte Erdseil, so bedeutet dies eine extreme elektromagnetische Einwirkung. Der vorliegende Beitrag befasst sich mit der Simulation eines solchen Blitzeinschlages und dessen Auswirkungen auf den Netzanschluss und die Komponenten der elektrischen Eigenbedarfsanlagen eines Kraftwerks auf den unterlagerten Spannungsebenen. Die dabei gewonnenen Erkenntnisse lassen sich ohne Einschränkungen auf Industrieanlagen mit Mittelspannungs-Netzanschluss und ohne eigener Stromversorgung übertragen.
[Paper of the X International Symposium on Lightning Protection 9th - 13th November, 2009 - Curitiba, Brazil. 6 pages] The international standard IEC 62305-3, published in 2006, requires as an integral part of the lightning protection system (LPS) the consideration of a separation distance between the conductors of the LPS and metal and electrical installations inside the structure to be protected. IEC 62305-3 gives two different methods for this calculation: a standard, simplified approach and a more detailed approach, which differ especially regarding the treatment of the current sharing effect on the LPS conductors. Hence, different results for the separation distance are possible, leading to some discrepancies in the use of the standard. The standard approach defined in the main part (Clause 6.3) and in Annex C of the standard in some cases may lead to a severe oversizing of the required separation distance. The detailed approach described in Annex E naturally gives more correct results. However, a calculation of the current sharing amongst all parts of the air-termination and downconductor network is necessary, in many cases requiring the use of network analysis programs. In this paper simplified methods for the assessment of the current sharing are presented, which are easy to use as well as sufficiently adequate.
In the presented paper data collected from the field related to damage statistics of electrical and electronic apparatus in household are reported and investigated. These damages (total number approx. 74000 cases), registered by five German insurance companies in 2005 and 2006, were adviced by customers as caused by lightning overvoltages. With the use of stochastical methods it is possible, to reasses the collected data and to distinguish between cases, which are with high probability caused by lightning overvoltages, and those, which are not. If there was an indication for a direct strike, this case was excluded, so the focus was only on indirect lightning flashes, i.e. only flashes to ground near the structure and flashes to or nearby an incoming service line were investigated. The data from the field contain the location of damaged apparatus (residence of the policy holder) and the distances of the nearest cloud-to-ground stroke to the location of the damage registered by the German lightning location network BLIDS at the date of damage. The statistical data along with some complementary numerical simulations allow to verify the correspondence of the Standards rules used for IEC 62305-2 with the field data and to define some correction needs. The results could lead to a better understanding whether a damage reported to an insurance company is really caused by indirect lightning, or not.
Die ökologische Umgestaltung der Dhünn in Leverkusen – Ein Beispiel für die praktische Planung
(2009)
Dipl.-Ing. (FH) Dieter Stein M.Sc (Environmental Engineering) - Landschaftsarchitekt AKNW, Grevenbroich. 14 Seiten ( S. 78-91). Beitrag zum 2. Aachener Softwaretag in der Wasserwirtschaft <2, 2009, Aachen>. Zusammenfassung [des Autors] Unter Berücksichtigung vorhandener örtlicher Gegebenheiten und technischer Einrichtungen (wie z.B. Verkehrstrassen, Versorgungsleitungen, Einlaufbauwerke etc.) hat die Dhünn innerhalb der Deiche mehr Bewegungsfreiheit erhalten. Der Hochwasserschutz bleibt dabei weiterhin gewährleistet. Die Gehölzstrukturen im Uferbereich wurden weitgehend erhalten. Dort, wo die Bauarbeiten eine Entfernung von Gehölzen erforderlich machten, wurden die Flächen bewusst einer eigenständigen Entwicklung überlassen. In diesen Bereichen werden sich im Laufe der Zeit von selbst neue Pflanzen und Gehölze ansiedeln. Mit der naturnahen Umgestaltung der Dhünn als "Starthilfe" kann die Natur die weitere Entwicklung übernehmen: Tier- und Pflanzenarten können sich das ehemals kanalartig ausgebaute Gewässer "zurückerobern", Fische und Kleintiere finden Nahrung und Ruheplätze. Für die Menschen entsteht ein wertvoller Erholungsraum mitten in der Stadt. Trotz zahlreicher Akteure und erheblicher Restriktionen konnte das Projekt in relativ kurzer Zeit realisiert werden. Dem Wupperverband (Untere Lichtenplatzer Str. 100; 42289 Wuppertal) und hier vor allem den Projektleitern Herrn Arnim Lützenberger und Herrn Andreas Oberborbeck sei an dieser Stelle besonders für eine hervorragende Zusammenarbeit gedankt.
Dipl.-Ing. Hartmut Hoevel - Erftverband, Bergheim. 3 Seiten (S. 75-77). Beitrag zum 2. Aachener Softwaretag in der Wasserwirtschaft <2, 2009, Aachen> Die Erft ist ein linker Nebenfluss des Rheins. Der Fluss ist durch eingeleitetes Sümpfungswasser aus dem rheinischen Braunkohletagebau hinsichtlich der Wassermenge und der Temperatur stark belastet. Die vorgestellten Überlegungen betreffen die Fragen: 1. Wie soll die Erft im Jahr 2045, also nach dem voraussichtlichen Ende der Tagebauaktivitäten im Rheinischen Braunkohlerevier und damit einhergehender Beenigung der Sümpfungswassereinleitung, aussehen? 2. Wie schnell und auf welche Weise soll die Umgestaltung der Erft vonstatten gehen?
Mischwassereinleitungen in Gewässer nach BWK Merkblatt M3 - Vorteile des detaillierten Nachweises
(2009)
Dipl.-Ing. Brigitte Huber und Dr.-Ing. Gerd Demny - Wasserverband Eifel Rur, Düren. 16 Seiten ( S. 59-74). Beitrag zum 2. Aachener Softwaretag in der Wasserwirtschaft <2, 2009, Aachen> Zusammenfassung [der Autoren] Für das städtisch geprägte Einzugsgebiet des Broicher Baches sind ein vereinfachter und ein detaillierter Nachweis nach BWK-M3 durchgeführt worden. Dabei zeigt sich, dass die Methodik des vereinfachten Nachweises nicht geeignet ist, um eine realitätsnahe Abbildung der einleitungsgeprägten Abflüsse des Gewässers zu erhalten. Dies ist insbesondere auf die Vernachlässigung von Wellentranslation und -retention im Gerinne zurückzuführen. Die dadurch entstehende Fehleinschätzung der Abflussverhältnisse versperrt den Blick auf eine situationsgerechte Maßnahmenplanung. Der mit Hilfe eines NA-Modells geführte detaillierte Nachweis ist zwar in der Erstellung aufwändiger, zeichnet aber ein reales Bild der Abflusserhöhung durch Einleitungen. Mit Hilfe des Modells können die wesentlichen Einflüsse schnell lokalisiert und zielführende Maßnahmenvarianten identifiziert werden. In dem hier vorgestellten Beispiel des Broicher Baches können die ursprünglich identifizierten acht Maßnahmen auf eine reduziert werden. Das Gesamtvolumen der erforderlichen Rückhaltungen wird um die Hälfte verringert. Der Vergleich beider Nachweismethoden legt nach Ansicht der Autoren nahe, den vereinfachten Nachweis höchstens für eine erste Einschätzung des Maßnahmenbedarfs anzuwenden. Die Maßnahmenidentifikation und -dimensionierung sollte grundsätzlich mit der detaillierten Nachweismethode durchgeführt werden, die auf einem entsprechenden NA-Modell basiert. Dies gilt insbesondere für Gewässerstrecken, deren Abfluss durch mehrere, hintereinander liegende Einleitungsstellen geprägt ist.
Dr.-Ing. Oliver Stoschek [u.a.] DHI Wasser und Umwelt GmbH, Syke. 14 S. (S. 45-58). Beitrag zum 2. Aachener Softwaretag in der Wasserwirtschaft <2, 2009, Aachen> Ökologische Modelle zur Berechnung der Temperaturveränderung und den Einfluss von Kühlwasser auf die Wassertemperatur der Elbe. Die vorgelegte Arbeit wurde beauftragt und unterstützt von der ARGE Elbe im Zuge der Neuauflage des Wärmelastplans Elbe.
Dipl.-Ing. Stefan Overkamp - GISWORKS GbR, Velbert. 11 S. (S. 7-17). Beitrag zum 2. Aachener Softwaretag in der Wasserwirtschaft <2, 2009, Aachen> Aus der Gliederung: 1 Geoinformationssysteme 2 Anforderungen an eine kommunale Geodateninfrastruktur (GDI) 3 Komponenten einer GDI 3.1 Geodatenmanagement 3.2 Geodatenhaltung 3.3 High-End-GIS 3.4 intraGIS 4 GISWORKS 5 Weiterführende Informationen