TY - CHAP A1 - Nowack, N. A1 - Röth, Thilo A1 - Bührig-Polaczek, Andreas A1 - Klaus, G. ED - Hirsch, Jürgen T1 - Advanced Sheet Metal Components Reinforced by Light Metal Cast Structures T2 - Aluminium alloys : their physical and mechanical properties ; [proceedings of the 11th International Conference on Aluminium Alloys, 22 - 26 Sept. 2008, Aachen, Germany ; ICAA 11] Y1 - 2008 SN - 978-3-527-32367-8 IS - 2 SP - 2374 EP - 2381 ER - TY - CHAP A1 - Bührig-Polaczek, Andreas A1 - Röth, Thilo A1 - Baumeister, E. A1 - Nowack, N. A1 - Süßmann, Torsten T1 - Hybride Leichtbaustrukturen in Stahlblech-Leichtmetall Verbundguss N2 - Stahl-Leichtmetall-Hybride mit hohen Leistungspotentialen können heute wirtschaftlich abgebildet werden und eignen sich möglicherweise auch zum Einsatz in Fahrzeugkarosserien KW - Karosseriebau KW - Verbundguss KW - Stahlblech-Leichtmetall Verbundguss KW - Stahlblech-Leichtmetall-Hybride KW - Lightweight car body construction Y1 - 2006 ER - TY - CHAP A1 - Lao, B. A1 - Bührig-Polaczek, Andreas A1 - Röth, Thilo ED - Wielage, Bernhard T1 - Funktionsintegrierte Leichtbaustrukturen in gussintensiver Metall-Hybridbauweise T2 - Verbundwerkstoffe und Werkstoffverbunde: Tagungsband zum 18. Symposium ; 30.03.2011 bis 01.04.2011, Chemnitz Y1 - 2011 SN - 978-3-00-033801-4 N1 - Schriftenreihe Werkstoffe und werkstofftechnische Anwendungen ; 41 SP - 413 EP - 421 PB - Eigenverlag CY - Chemnitz ER - TY - JOUR A1 - Esch, Thomas A1 - Salber, Wolfgang A1 - Kemper, Hans A1 - Staay, F. van der T1 - Der elektromechanische Ventiltrieb - Systembaustein für zukünftige Antriebskonzepte, Teil 1. JF - Motortechnische Zeitschrift (MTZ). Y1 - 2000 U6 - https://doi.org/10.1007/bf03227081 SN - 0024-8525 VL - 61 IS - 12 SP - 826 EP - 836 PB - Springer Nature CY - Basel ER - TY - CHAP A1 - Lettini, Antonio A1 - Havermann, Marc A1 - Guidetti, Marco A1 - Fornaciari, Andrea T1 - Improved functionalities and energy saving potential on mobile machines combining electronics with flow sharing valve and variable displacement pump T2 - 7th International Fluid Power Conference - Vol. 3 - Aachen Efficiency through Fluid Power Workshop Proceedings Y1 - 2010 SN - 978-3-940565-92-1 N1 - IFK, 7, Internationales Fluidtechnisches Kolloquium, 7., Aachen, DE, 2010-03-22 - 2010-03-24 SP - 103 EP - 114 PB - Apprimus Verlag CY - Aachen ER - TY - JOUR A1 - Schmitz, Günter A1 - Altherr, M. A1 - Hofmann, O. A1 - Pischinger, Martin T1 - Anwendung moderner Simulationstools für die Entwicklung eines elektromagnetischen Ventilaktuators JF - TransMechatronik : Entwicklung und Transfer von Entwicklungssystemen der Mechatronik / Aachener Workshop TransMechatronik 26. Mai 1998, Technologiezentrum am Europaplatz Y1 - 1998 SN - 3-931466-37-X SP - 55 EP - 74 PB - Heinz-Nixdorf-Inst, Univ.-GH Paderborn CY - Paderborn ER - TY - JOUR A1 - Esch, Thomas A1 - Pischinger, Martin A1 - Göbel, T. T1 - Luft- und Kraftstoffzumessung bei Ottomotoren mit variabler Ventilsteuerung JF - Motortechnische Zeitschrift. 57 (1996), H. 2 Y1 - 1996 SN - 0024-8525 SP - 106 EP - 115 ER - TY - JOUR A1 - Esch, Thomas A1 - Pischinger, Martin A1 - Hagen, Jürgen A1 - Salber, Wolfgang T1 - Möglichkeiten der ottomotorischen Prozeßführung bei Verwendung des elektromechanischen Ventiltriebs Y1 - 1998 N1 - Konferenz-Einzelbericht : 7. Aachener Kolloquium Fahrzeug- u. Motorentechnik 05.-07. Okt. 1998, Bd. 2 SP - 987 EP - 1015 ER - TY - BOOK A1 - Ley, Wilfried A1 - Wittmann, Klaus A1 - Hallmann, Willi T1 - Handbook of space technology Y1 - 2009 SN - 978-0-470-69739-9 PB - Wiley CY - Chichester ER - TY - CHAP A1 - Recker, Elmar A1 - Bosschaerts, Walter A1 - Wagemakers, Rolf A1 - Hendrick, Patrick A1 - Funke, Harald A1 - Börner, Sebastian T1 - Experimental study of a round jet in cross-flow at low momentum ratio N2 - With the final objective of optimizing the "Micromix" hydrogen combustion principle, a round jet in a laminar cross-flow prior to its combustion is investigated experimentally using Stereoscopic Particle Image Velocimetry. Measurements are performed at a jet to cross-stream momentum ratio of 1 and a Reynolds number, based on the jet diameter and jet velocity, of 1600. The suitability to combine side, top and end views is analyzed statistically. The statistical theory of testing hypotheses, pertaining to the joint distribution of the averaged velocity along intersecting observation planes, is employed. Overall, the averaged velocity fields of the varying observation planes feature homogeneity at a 0.05 significance level. Minor discrepancies are related to the given experimental conditions. By use of image maps, averaged and instantaneous velocity fields, an attempt is made to elucidate the flow physics and a kinematically consistent vortex model is proposed. In the time-averaged flow field, the principal vortical systems were identified and the associated mixing visualized. The jet trajectory and physical dimensions scale with the momentum ratio times the jet diameter. The jet/cross-flow mixture converging upon the span-wise centre-line, the lifting action of the Counter Rotating Vortex Pair and the reversed flow region contribute to the high entrainment and mixedness. It is shown that the jet width is larger on the downstream side as compared to the upstream side of the centre-streamline. The deepest penetration of the particles on the outer boundary occurs in the centre-plane. Meanwhile, with increasing off-centre position, the boundaries all lay further from the centre-line position than does the boundary in the centre-plane, corresponding to a kidney-like shape of the flow cross-section. The generation of the Counter Rotating Vortex Pair and the instability mechanism is documented by instantaneous image maps and vector fields. The necessary circulation for the Counter Rotating Vortex Pair originates from a combined effect of steady in-hole, hanging and wake vortices. The strong cross-flow and jet interaction induces a three-dimensional waving, the stream-wise Counter Rotating Vortex Pair pair, leading to the formation of Ring Like Vortices. A secondary Counter Rotating Vortex Pair forms on top of the primary Counter Rotating Vortex Pair, resulting in mixing by "puffs". Overall, Stereoscopic Particle Image Velocimetry proofed capable of elucidating the Jet in Cross-Flow complex flow field. The gained insight in the mixing process will definitely contribute to the "Micromix" hydrogen combustion optimization. Y1 - 2010 N1 - 15th International Symposium on Applications of Laser Techniques to Fluid Mechanics Lisbon, Portugal, 05-08 July, 2010 ER - TY - CHAP A1 - Funke, Harald A1 - Robinson, A. E. A1 - Hendrick, P. A1 - Wagemakers, R. T1 - Design and Testing of a Micromix Combustor With Recuperative Wall Cooling for a Hydrogen Fuelled µ-Scale Gas Turbine T2 - Conference Proceedings ASME Turbo Expo 2010: Power for Land, Sea, and Air. Volume 5: Industrial and Cogeneration; Microturbines and Small Turbomachinery; Oil and Gas Applications; Wind Turbine Technology N2 - For more than a decade up to now there is an ongoing interest in small gas turbines downsized to micro-scale. With their high energy density they offer a great potential as a substitute for today’s unwieldy accumulators, found in a variety of applications like laptops, small tools etc. But micro-scale gas turbines could not only be used for generating electricity, they could also produce thrust for powering small unmanned aerial vehicles (UAVs) or similar devices. Beneath all the great design challenges with the rotating parts of the turbomachinery at this small scale, another crucial item is in fact the combustion chamber needed for a safe and reliable operation. With the so called regular micromix burning principle for hydrogen successfully downscaled in an initial combustion chamber prototype of 10 kW energy output, this paper describes a new design attempt aimed at the integration possibilities in a μ-scale gas turbine. For manufacturing the combustion chamber completely out of stainless steel components, a recuperative wall cooling was introduced to keep the temperatures in an acceptable range. Also a new way of an integrated ignition was developed. The detailed description of the prototype’s design is followed by an in depth report about the test results. The experimental investigations comprise a set of mass flow variations, coupled with a variation of the equivalence ratio for each mass flow at different inlet temperatures and pressures. With the data obtained by an exhaust gas analysis, a full characterisation concerning combustion efficiency and stability of the prototype chamber is possible. Furthermore the data show a full compliance with the expected operating requirements of the designated μ-scale gas turbine. Y1 - 2010 SN - 978-0-7918-4400-7 U6 - https://doi.org/10.1115/GT2010-23453 N1 - ASME Turbo Expo 2010: Power for Land, Sea, and Air, June 14–18, 2010, Glasgow, UK SP - 587 EP - 596 PB - ASME CY - New York, NY ER - TY - CHAP A1 - Funke, Harald A1 - Börner, Sebastian A1 - Robinson, A. A1 - Hendrick, P. A1 - Recker, E. T1 - Low NOx H2 combustion for industrial gas turbines of various power ranges Y1 - 2010 N1 - 5th International Gas Turbine Conference ETN-IGTC, ETN-2010-42, Brussels, Belgium, October 2010 ER - TY - GEN A1 - Maiwald, Volker A1 - Dachwald, Bernd T1 - Mission design for a multiple-rendezvous mission to Jupiter's trojans N2 - In this paper, we will provide a feasible mission design for a multiple-rendezvous mission to Jupiter's Trojans. It is based on solar electric propulsion, as being currently used on the DAWN spacecraft, and other flight-proven technology. First, we have selected a set of mission objectives, the prime objective being the detection of water -especially subsurface water -to provide evidence for the Trojans' formation at large solar distances. Based on DAWN and other comparable missions, we have determined suitable payload instruments to achieve these objectives. Afterwards, we have designed a spacecraft that is able to carry the selected payload to the Trojan region and rendezvous successively with three target bodies within a maximum mission duration of 15 years. Accurate low-thrust trajectories have been obtained with a global low-thrust trajectory optimization program (InTrance). During the transfer from Earth to the first target, the spacecraft is propelled by two RIT-22 ion engines from EADS Astrium, whereas a single RIT-15 is used for transfers within the Trojan region to reduce the required power. For power generation, the spacecraft uses a multi-junction solar array that is supported by concentrators. To achieve moderate mission costs, we have restricted the launch mass to a maximum of 1600 kg, the maximum interplanetary injection capability of a Soyuz/Fregat launcher. Our final layout has a mass of 1400 kg, yielding a margin of about 14%. Nestor (a member of the L4-population) was determined as the first mission target. It can be reached within 4.6 years from launch. The fuel mass ratio for this transfer is about 35%. The stay time at Nestor is 1.2 years. Eurymedon was selected as the second target (transfer time 3.5 years, stay time 3.0 years) and Irus as the third target (transfer time 2.2 years). The transfers within the Trojan L4-population can be accomplished with fuel mass ratios of about 3% for each trajectory leg. Including the stay times in orbit around the targets, the mission can be accomplished within a total duration of about 14.5 years. According to our mission analysis, it is also feasible to fly to the L5-population with similar flight times. It has to be noted that -for a first analysis -we have taken only the named targets into account. Allowing also rendezvous with unnamed objects will very likely decrease the mission duration. Based on a scaling of DAWN's mission costs (due to comparable scientific instruments and mission objectives), and taking into account the longer mission duration and the potential re-use of already developed technology, we have estimated that these three rendezvous can be accomplished with a budget of about 250 Million Euros, i.e. about 25% of ROSETTA's budget. Y1 - 2010 N1 - 38th COSPAR Scientific Assembly. Held 18-15 July 2010,Bremen, Germany SP - 3 ER - TY - JOUR A1 - Sanchez-Cespedes, Lina Maria A1 - Leasure, Douglas Ryan A1 - Tejedor-Garavito, Natalia A1 - Amaya Cruz, Glenn Harry A1 - Garcia Velez, Gustavo Adolfo A1 - Mendoza Beltrán, Andryu Enrique A1 - Marín-Salazar, Yenny Andrea A1 - Esch, Thomas A1 - Tatem, Andrew J. A1 - Ospina Bohórquez, Mariana Francisca T1 - Social cartography and satellite-derived building coverage for post-census population estimates in difficult-to-access regions of Colombia JF - Population studies : a Journal of Demography N2 - Effective government services rely on accurate population numbers to allocate resources. In Colombia and globally, census enumeration is challenging in remote regions and where armed conflict is occurring. During census preparations, the Colombian National Administrative Department of Statistics conducted social cartography workshops, where community representatives estimated numbers of dwellings and people throughout their regions. We repurposed this information, combining it with remotely sensed buildings data and other geospatial data. To estimate building counts and population sizes, we developed hierarchical Bayesian models, trained using nearby full-coverage census enumerations and assessed using 10-fold cross-validation. We compared models to assess the relative contributions of community knowledge, remotely sensed buildings, and their combination to model fit. The Community model was unbiased but imprecise; the Satellite model was more precise but biased; and the Combination model was best for overall accuracy. Results reaffirmed the power of remotely sensed buildings data for population estimation and highlighted the value of incorporating local knowledge. KW - modelled population estimates KW - population and housing census KW - GIS KW - remote sensing KW - Bayesian statistics Y1 - 2023 U6 - https://doi.org/10.1080/00324728.2023.2190151 SN - 1477-4747 VL - 78 IS - 1 SP - 3 EP - 20 PB - Taylor & Francis CY - London ER - TY - CHAP A1 - Börner, Sebastian A1 - Funke, Harald A1 - Hendrick, P. A1 - Recker, E. T1 - Control system modifications for a hydrogen fuelled gas-turbine T2 - Proceedings of ISROMAC 13 Y1 - 2010 SN - 978-1-617-38848-4 N1 - 13th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery 2010 (ISROMAC-13), Honolulu, Hawaii, USA, April 4-7, 2010 SP - 665 EP - 670 PB - Curran CY - Red Hook, NY ER - TY - JOUR A1 - Christen, Marc A1 - Kowalski, Julia A1 - Bartelt, Perry T1 - RAMMS: Numerical simulation of dense snow avalanches in three-dimensional terrain JF - Cold Regions Science and Technology N2 - Numerical avalanche dynamics models have become an essential part of snow engineering. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, their application poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to construct hazard scenarios which involve the careful specification of initial conditions (release zone location and dimensions) and definition of appropriate friction parameters. The interpretation of simulation results requires an understanding of the numerical solution schemes and easy to use visualization tools. We discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with accurate second-order numerical solution schemes. The model allows the specification of multiple release zones in three-dimensional terrain. Snow cover entrainment is considered. Furthermore, two different flow rheologies can be applied: the standard Voellmy–Salm (VS) approach or a random kinetic energy (RKE) model, which accounts for the random motion and inelastic interaction between snow granules. We present the governing differential equations, highlight some of the input and output features of RAMMS and then apply the models with entrainment to simulate two well-documented avalanche events recorded at the Vallée de la Sionne test site. KW - RAMMS KW - snow KW - avalanche Y1 - 2010 U6 - https://doi.org/10.1016/j.coldregions.2010.04.005 SN - 1872-7441 VL - 63 IS - 1-2 SP - 1 EP - 14 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Mulsow, Niklas A. A1 - Hülsen, Benjamin A1 - Gützlaff, Joel A1 - Spies, Leon A1 - Bresser, Andreas A1 - Dabrowski, Adam A1 - Czupalla, Markus A1 - Kirchner, Frank T1 - Concept and design of an autonomous micro rover for long term lunar exploration T2 - Proceedings of the 74th International Astronautical Congress N2 - Research on robotic lunar exploration has seen a broad revival, especially since the Google Lunar X-Prize increasingly brought private endeavors into play. This development is supported by national agencies with the aim of enabling long-term lunar infrastructure for in-situ operations and the establishment of a moon village. One challenge for effective exploration missions is developing a compact and lightweight robotic rover to reduce launch costs and open the possibility for secondary payload options. Existing micro rovers for exploration missions are clearly limited by their design for one day of sunlight and their low level of autonomy. For expanding the potential mission applications and range of use, an extension of lifetime could be reached by surviving the lunar night and providing a higher level of autonomy. To address this objective, the paper presents a system design concept for a lightweight micro rover with long-term mission duration capabilities, derived from a multi-day lunar mission scenario at equatorial regions. Technical solution approaches are described, analyzed, and evaluated, with emphasis put on the harmonization of hardware selection due to a strictly limited budget in dimensions and power. Y1 - 2023 N1 - 74. International Astronautical Congress (IAC-2023), October 2-6 2023, Baku, Azerbaijan PB - dfki CY - Saarbrücken ER - TY - CHAP A1 - Mayntz, Joscha A1 - Keimer, Jona A1 - Dahmann, Peter A1 - Hille, Sebastian A1 - Stumpf, Eike A1 - Fisher, Alex A1 - Dorrington, Graham T1 - Electrical Drive and Regeneration in General Aviation Flight with Propellers T2 - Deutscher Luft- und Raumfahrtkongress 2020 N2 - Electric flight has the potential for a more sustainable and energy-saving way of aviation compared to fossil fuel aviation. The electric motor can be used as a generator inflight to regenerate energy during descent. Three different approaches to regenerating with electric propeller powertrains are proposed in this paper. The powertrain is to be set up in a wind tunnel to determine the propeller efficiency in both working modes as well as the noise emissions. Furthermore, the planned flight tests are discussed. In preparation for these tests, a yaw stability analysis is performed with the result that the aeroplane is controllable during flight and in the most critical failure case. The paper shows the potential for inflight regeneration and addresses the research gaps in the dual role of electric powertrains for propulsion and regeneration of general aviation aircraft. KW - Propeller Aerodynamics KW - Flight Tests KW - Flight Mechanics KW - Electrical Flight KW - Inflight Regeneration, Recuperation Y1 - 2022 U6 - https://doi.org/10.25967/530100 N1 - Deutscher Luft- und Raumfahrtkongress 2020, 1. - 3. September 2020, Online PB - DGLR CY - Bonn ER - TY - GEN A1 - Gamgami, Farid A1 - Czupalla, Markus A1 - Garcia, Antonio A1 - Agnolon, David T1 - From planetary transits to spacecraft design: achieving PLATO’s pointing performance T2 - A7. Symposium on technological Requirement for future space astronomy and solar-system science missions N2 - In the last decades, several hundred exoplanets could be detected thanks to space-based observatories, namely CNES’ COROT and NASA’s Kepler. To expand this quest ESA plans to launch CHEOPS as the f irst small class mission in the cosmic visions program (S1) and PLATO as the 3rd medium class mission, so called M3 . PLATO’s primary objective is the detection of Earth like Exoplanets orbiting solar type stars in the habitable zone and characterisation of their bulk properties. This is possible by precise lightcurve measurement via 34 cameras. That said it becomes obvious that accurate pointing is key to achieve the required signal to noise ratio for positive transit detection. The paper will start with a comprehensive overview of PLATO’s mission objectives and mission architecture. Hereafter, special focus will be devoted to PLATO’s pointing requirements. Understanding the very nature of PLATO’s pointing requirements is essential to derive a design baseline to achieve the required performance. The PLATO frequency domain is of particular interest, ranging from 40 mHz to 3 Hz. Due to the very different time-scales involved, the spectral pointing requirement is decomposed into a high frequency part dominated by the attitude control system and the low frequency part dominated by the thermo-elastic properties of the spacecraft’s configuration. Both pose stringent constraints on the overall design as well as technology properties to comply with the derived requirements and thus assure a successful mission. Y1 - 2016 N1 - 67th International Astronautical Congress, 26. - 30. September 2016, Guadalajara, Mexico ER - TY - RPRT A1 - Barnat, Miriam A1 - Arntz, Kristian A1 - Bernecker, Andreas A1 - Fissabre, Anke A1 - Franken, Norbert A1 - Goldbach, Daniel A1 - Hüning, Felix A1 - Jörissen, Jörg A1 - Kirsch, Ansgar A1 - Pettrak, Jürgen A1 - Rexforth, Matthias A1 - Josef, Rosenkranz A1 - Terstegge, Andreas T1 - Strategische Gestaltung von Studiengängen für die Zukunft: Ein kollaborativ entwickeltes Self-Assessment BT - Diskussionspapier Nr. 33 T2 - Hochschulforum Digitalisierung - Diskussionspapier N2 - Das Diskussionspapier beschreibt einen Prozess an der FH Aachen zur Entwicklung und Implementierung eines Self-Assessment-Tools für Studiengänge. Dieser Prozess zielte darauf ab, die Relevanz der Themen Digitalisierung, Internationalisierung und Nachhaltigkeit in Studiengängen zu stärken. Durch Workshops und kollaborative Entwicklung mit Studiendekan:innen entstand ein Fragebogen, der zur Reflexion und strategischen Weiterentwicklung der Studiengänge dient. Y1 - 2024 SN - 2365-7081 PB - Stifterverband für die Deutsche Wissenschaft CY - Berlin ER -