TY - CHAP A1 - Dahmann, Peter T1 - Stemme S10 VTX als multifunktionales Forschungsflugzeug T2 - Deutscher Luft- und Raumfahrtkongress 2011 : Bremen, 27. bis 29. September 2011 ; Tagungsband Y1 - 2011 SN - 978-3-9321-8274-7 SP - 357 EP - 364 PB - Dt. Gesellschaft für Luft- und Raumfahrt CY - Bonn ER - TY - CHAP A1 - Carzana, Livio A1 - Dachwald, Bernd A1 - Noomen, Ron T1 - Model and trajectory optimization for an ideal laser-enhanced solar sail T2 - 68th International Astronautical Congress N2 - A laser-enhanced solar sail is a solar sail that is not solely propelled by solar radiation but additionally by a laser beam that illuminates the sail. This way, the propulsive acceleration of the sail results from the combined action of the solar and the laser radiation pressure onto the sail. The potential source of the laser beam is a laser satellite that coverts solar power (in the inner solar system) or nuclear power (in the outer solar system) into laser power. Such a laser satellite (or many of them) can orbit anywhere in the solar system and its optimal orbit (or their optimal orbits) for a given mission is a subject for future research. This contribution provides the model for an ideal laser-enhanced solar sail and investigates how a laser can enhance the thrusting capability of such a sail. The term ”ideal” means that the solar sail is assumed to be perfectly reflecting and that the laser beam is assumed to have a constant areal power density over the whole sail area. Since a laser beam has a limited divergence, it can provide radiation pressure at much larger solar distances and increase the radiation pressure force into the desired direction. Therefore, laser-enhanced solar sails may make missions feasible, that would otherwise have prohibitively long flight times, e.g. rendezvous missions in the outer solar system. This contribution will also analyze exemplary mission scenarios and present optimial trajectories without laying too much emphasis on the design and operations of the laser satellites. If the mission studies conclude that laser-enhanced solar sails would have advantages with respect to ”traditional” solar sails, a detailed study of the laser satellites and the whole system architecture would be the second next step Y1 - 2017 N1 - 68th International Astronautical Congress: Unlocking Imagination, Fostering Innovation and Strengthening Security, IAC 2017, 2017-09-25 → 2017-09-29, Adelaide, Australia ER - TY - JOUR A1 - Dachwald, Bernd A1 - Tsinas, L. T1 - A combined neural and genetic learning algorithm / Tsinas, L. ; Dachwald, B. JF - Proceedings of the First IEEE Conference on Evolutionary Computation, 1994. IEEE World Congress on Computational Intelligence. Y1 - 1994 SN - 0-7803-1899-4 SP - 770 EP - 774 CY - Orlando, Fl ER - TY - JOUR A1 - Dahmann, Peter T1 - Funktionsweise von Hydraulikfiltern JF - Ölhydraulik und Pneumatik. 37 (1993), H. 2 Y1 - 1993 SN - 0341-2660 SP - 118 EP - 122 ER - TY - CHAP A1 - Wahle, Michael T1 - Optimale Auslegung von Schwingungsdämpfern zur Schwingungsberuhigung elastischer Strukturen T2 - Dämpfung von Schwingungen bei Maschinen und Bauwerken : Tagung Nürnberg, 9. u. 10. April 1987. - (VDI-Berichte ; 627) Y1 - 1987 SN - 3-18-090627-8 SP - 355 EP - 373 PB - VDI-Verl. CY - Düsseldorf ER - TY - JOUR A1 - Polaczek, Christa A1 - Henn, Gudrun T1 - Gute Vorkenntnisse verkürzen die Studienzeit JF - Mathematikinformation : eine Zeitschrift von Begabtenförderung Mathematik e.V. Y1 - 2008 SN - 1612-9156 VL - 2008 IS - 49 SP - 46 EP - 50 PB - Begabtenförderung Mathematik CY - Neubiberg ER - TY - JOUR A1 - Schopen, Oliver A1 - Shah, Neel A1 - Esch, Thomas A1 - Shabani, Bahman T1 - Critical quantitative evaluation of integrated health management methods for fuel cell applications JF - International Journal of Hydrogen Energy N2 - Online fault diagnostics is a crucial consideration for fuel cell systems, particularly in mobile applications, to limit downtime and degradation, and to increase lifetime. Guided by a critical literature review, in this paper an overview of Health management systems classified in a scheme is presented, introducing commonly utilised methods to diagnose FCs in various applications. In this novel scheme, various Health management system methods are summarised and structured to provide an overview of existing systems including their associated tools. These systems are classified into four categories mainly focused on model-based and non-model-based systems. The individual methods are critically discussed when used individually or combined aimed at further understanding their functionality and suitability in different applications. Additionally, a tool is introduced to evaluate methods from each category based on the scheme presented. This tool applies the technique of matrix evaluation utilising several key parameters to identify the most appropriate methods for a given application. Based on this evaluation, the most suitable methods for each specific application are combined to build an integrated Health management system. KW - Fuel cell KW - Health management system KW - Online diagnostic KW - Fault detection KW - Non-model-based Evaluation Y1 - 2024 U6 - https://doi.org/10.1016/j.ijhydene.2024.05.156 SN - 0360-3199 VL - 70 SP - 370 EP - 388 PB - Elsevier CY - Amsterdam ER - TY - CHAP A1 - Kohlberger, David-Sharif A1 - Wild, Dominik A1 - Kasper, Stefan A1 - Czupalla, Markus T1 - Modeling and analyses of a thermal passively stabilized LEO/GEO star tracker with embedded phase change material applying the Infused Thermal Solutions (ITS) method T2 - ICES202: Satellite, Payload, and Instrument Thermal Control N2 - Phase change materials offer a way of storing excess heat and releasing it when it is needed. They can be utilized as a method to control thermal behavior without the need for additional energy. This work focuses on exploring the potential of using phase change materials to passively control the thermal behavior of a star tracker by infusing it with a fitting phase change material. Based on the numerical model of the star trackers thermal behavior using ESATAN-TMS without implemented phase change material, a fitting phase change material for selected orbits is chosen and implemented in the thermal model. The altered thermal behavior of the numerical model after the implementation is analyzed for different amounts of the chosen phase change materials using an ESATAN-based subroutine developed by the FH Aachen. The PCM-modelling-subroutine is explained in the paper ICES-2021-110. The results show that an increasing amount of phase change material increasingly damps temperature oscillations. Using an integral part structure some of the mass increase can be compensated. KW - passive thermal control KW - PCM KW - star tracker KW - Infused Thermal Solutions KW - GEO KW - LEO Y1 - 2021 N1 - 50th International Conference on Environmental Systems, 12-15 July 2021, held virtually PB - Texas Tech University CY - Lubbock, Tex. ER - TY - JOUR A1 - Stiemer, Luc Nicolas A1 - Thoma, Andreas A1 - Braun, Carsten T1 - MBT3D: Deep learning based multi-object tracker for bumblebee 3D flight path estimation JF - PLoS ONE N2 - This work presents the Multi-Bees-Tracker (MBT3D) algorithm, a Python framework implementing a deep association tracker for Tracking-By-Detection, to address the challenging task of tracking flight paths of bumblebees in a social group. While tracking algorithms for bumblebees exist, they often come with intensive restrictions, such as the need for sufficient lighting, high contrast between the animal and background, absence of occlusion, significant user input, etc. Tracking flight paths of bumblebees in a social group is challenging. They suddenly adjust movements and change their appearance during different wing beat states while exhibiting significant similarities in their individual appearance. The MBT3D tracker, developed in this research, is an adaptation of an existing ant tracking algorithm for bumblebee tracking. It incorporates an offline trained appearance descriptor along with a Kalman Filter for appearance and motion matching. Different detector architectures for upstream detections (You Only Look Once (YOLOv5), Faster Region Proposal Convolutional Neural Network (Faster R-CNN), and RetinaNet) are investigated in a comparative study to optimize performance. The detection models were trained on a dataset containing 11359 labeled bumblebee images. YOLOv5 reaches an Average Precision of AP = 53, 8%, Faster R-CNN achieves AP = 45, 3% and RetinaNet AP = 38, 4% on the bumblebee validation dataset, which consists of 1323 labeled bumblebee images. The tracker’s appearance model is trained on 144 samples. The tracker (with Faster R-CNN detections) reaches a Multiple Object Tracking Accuracy MOTA = 93, 5% and a Multiple Object Tracking Precision MOTP = 75, 6% on a validation dataset containing 2000 images, competing with state-of-the-art computer vision methods. The framework allows reliable tracking of different bumblebees in the same video stream with rarely occurring identity switches (IDS). MBT3D has much lower IDS than other commonly used algorithms, with one of the lowest false positive rates, competing with state-of-the-art animal tracking algorithms. The developed framework reconstructs the 3-dimensional (3D) flight paths of the bumblebees by triangulation. It also handles and compares two alternative stereo camera pairs if desired. Y1 - 2023 U6 - https://doi.org/10.1371/journal.pone.0291415 SN - 1932-6203 N1 - Corresponding author: Luc Nicolas Stiemer VL - 18 IS - 9 PB - PLOS CY - San Fancisco ER - TY - CHAP A1 - Kreyer, Jörg A1 - Esch, Thomas T1 - Simulation Tool for Predictive Control Strategies for an ORCSystem in Heavy Duty Vehicles T2 - European GT Conference 2017 N2 - Scientific questions - How can a non-stationary heat offering in the commercial vehicle be used to reduce fuel consumption? - Which potentials offer route and environmental information among with predicted speed and load trajectories to increase the efficiency of a ORC-System? Methods - Desktop bound holistic simulation model for a heavy duty truck incl. an ORC System - Prediction of massflows, temperatures and mixture quality (AFR) of exhaust gas Y1 - 2017 N1 - European GT Conference 2017, 9.-10. Oktober 2017, Frankfurt a.M. ER -