TY - JOUR A1 - Staat, Manfred A1 - Vu, Duc Khoi T1 - Limit analysis of flaws in pressurized pipes and cylindrical vessels Part II: Circumferential defects JF - Engineering Fracture Mechanics ; 97(2013), H. 1 N2 - Upper and lower bound theorems of limit analyses have been presented in part I of the paper. Part II starts with the finite element discretization of these theorems and demonstrates how both can be combined in a primal–dual optimization problem. This recently proposed numerical method is used to guide the development of a new class of closed-form limit loads for circumferential defects, which show that only large defects contribute to plastic collapse with a rapid loss of strength with increasing crack sizes. The formulae are compared with primal–dual FEM limit analyses and with burst tests. Even closer predictions are obtained with iterative limit load solutions for the von Mises yield function and for the Tresca yield function. Pressure loading of the faces of interior cracks in thick pipes reduces the collapse load of circumferential defects more than for axial flaws. Axial defects have been treated in part I of the paper. Y1 - 2012 U6 - https://doi.org/10.1016/j.engfracmech.2012.05.017 SN - 0013-7944 VL - 97 SP - 314 EP - 333 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Staat, Manfred A1 - Vu, Duc-Khoi T1 - Limit analysis of flaws in pressurized pipes and cylindrical vessels. Part I: Axial defects JF - Engineering Fracture Mechanics. 74 (2007), H. 3 Y1 - 2007 SN - 0013-7944 SP - 431 EP - 450 ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Limit and Shakedown Analysis for Plastic Safety of Complex Structures JF - Transactions of the 14th International Conference on Structural Dynamics in Reactor Technology (SMiRT-14) / Livolant, M. [ed] Y1 - 1997 N1 - Vol. B, Paper B02/2 SP - 33 EP - 40 CY - Lyon ER - TY - THES A1 - Tran, Thanh Ngoc T1 - Limit and shakedown analysis of plates and shells including uncertainties Y1 - 2008 N1 - Chemnitz, Techn. Univ., Diss., 2008 ER - TY - CHAP A1 - Tran, Ngoc Trinh A1 - Trinh, Tu Luc A1 - Dao, Ngoc Tien A1 - Giap, Van Tan A1 - Truong, Manh Khuyen A1 - Dinh, Thuy Ha A1 - Staat, Manfred T1 - Limit and shakedown analysis of structures under random strength T2 - Proceedings of (NACOME2022) The 11th National Conference on Mechanics, Vol. 1. Solid Mechanics, Rock Mechanics, Artificial Intelligence, Teaching and Training N2 - Direct methods comprising limit and shakedown analysis is a branch of computational mechanics. It plays a significant role in mechanical and civil engineering design. The concept of direct method aims to determinate the ultimate load bearing capacity of structures beyond the elastic range. For practical problems, the direct methods lead to nonlinear convex optimization problems with a large number of variables and onstraints. If strength and loading are random quantities, the problem of shakedown analysis is considered as stochastic programming. This paper presents a method so called chance constrained programming, an effective method of stochastic programming, to solve shakedown analysis problem under random condition of strength. In this our investigation, the loading is deterministic, the strength is distributed as normal or lognormal variables. KW - Reliability of structures KW - Stochastic programming KW - Chance constrained programming KW - Shakedown analysis KW - Limit analysis Y1 - 2022 SN - 978-604-357-084-7 N1 - 11th National Conference on Mechanics (NACOME 2022), December 2-3, 2022, VNU University of Engineering and Technology, Hanoi, Vietnam SP - 510 EP - 518 PB - Nha xuat ban Khoa hoc tu nhien va Cong nghe (Verlag Naturwissenschaft und Technik) CY - Hanoi ER - TY - THES A1 - Tran, Ngoc Trinh T1 - Limit and Shakedown analysis of structures under stochastic conditions Y1 - 2019 U6 - https://doi.org/10.24355/dbbs.084-201902121135-0 PB - Technische Universität Braunschweig CY - Braunschweig ER - TY - JOUR A1 - Staat, Manfred T1 - Limit and shakedown analysis under uncertainty JF - International journal of computational methods : IJCM Y1 - 2013 SN - 0219-8762 SP - Publ. online PB - World Scientific Publishing CY - Singapore ER - TY - JOUR A1 - Staat, Manfred T1 - Limit and shakedown analysis under uncertainty JF - Tap chi Khoa hoc & ung dung - Dai hoc Ton Duc Thang Y1 - 2012 N1 - = Journal of Applied Sciences - Ton Duc Thang University VL - 19 SP - 45 EP - 47 ER - TY - JOUR A1 - Staat, Manfred A1 - Heitzer, M. T1 - Limit and Shakedown Analysis with Uncertain Data JF - Stochastic optimization techniques : numerical methods and technical applications / Marti, K. [ed] Y1 - 2002 SN - 3-540-42889-5 SP - 241 EP - 254 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Staat, Manfred A1 - Vu, Khoi Duc T1 - Limit loads of circumferentially flawed pipes and cylindrical vessels under internal pressure JF - International Journal of Pressure Vessels and Piping. 83 (2006), H. 3 Y1 - 2006 SN - 0308-0161 SP - 188 EP - 196 ER - TY - JOUR A1 - Samm, Doris A1 - Faissner, H. A1 - Frenzel, E. A1 - Heinrigs, W. T1 - Limit on axion decay into an electron pair / H. Faissner, E. Frenzel, W. Heinrigs, A. Preussger, D. Samm und U. Samm JF - Physics Letters B. Vol. 96 (1980), H. Issues 1-2 Y1 - 1980 SP - 201 EP - 205 ER - TY - JOUR A1 - Fink, G. R. A1 - Marshall, J. C. A1 - Shah, N. J. A1 - Weiss, P.H. A1 - Halligan, P. W. A1 - Grosse-Ruyken, M. A1 - Ziemons, Karl A1 - Zilles, K. A1 - Freund, H. J. T1 - Line bisection judgments implicate right parietal cortex and cerebellum as assessed by fMRI JF - Neurology Y1 - 2000 SN - 1526-632X VL - 54 IS - 6 SP - 1324 EP - 1331 ER - TY - JOUR A1 - Heuermann, Holger A1 - Schiek, Burkhard T1 - Line Network Network (LNN): an alternative in-fixture calibration procedure JF - IEEE transactions on microwave theory and techniques : MTT ; a publication of the IEEE Microwave Theory and Techniques Society. 45 (1997), H. 3 Y1 - 1997 SN - 0018-9480 SP - 408 EP - 413 ER - TY - JOUR A1 - Schäfer, Horst A1 - Worschech, L. A1 - Fischer, C. A1 - Schenk, H. (u.a.) T1 - Linearly Polarized Luminescence associated with Structural Defects in MBE grown ZnSe JF - Blue laser and light emitting diodes : [International Symposium on Blue Laser and Light Emitting Diodes (ISBLLED), Chiba, Japan , March 5 - 7, 1996] / ed. by A. Yoshikawa Y1 - 1996 SN - 4-274-90096-7 SP - 421 EP - 424 PB - Ohmsha [u.a.] CY - Tokyo ER - TY - JOUR A1 - Schütz, S. A1 - Weißbecker, G. A1 - Schroth, P. A1 - Schöning, Michael Josef T1 - Linkage of inanimate structures to biological systems – smart materials in biological micro- nanosystems JF - Smart materials : proceedings of the 1st Caesarium, Bonn, November 17 - 19, 1999 / Karl-Heinz Hoffmann ed. Y1 - 2001 SN - 3-540-67957-X SP - 149 EP - 157 PB - Springer CY - Berlin [u.a.] ER - TY - CHAP A1 - Engel, Mareike A1 - Thieringer, Julia A1 - Tippkötter, Nils T1 - Linking bioprocess engineering and electrochemistry for sustainable biofuel production T2 - Young Researchers Symposium, YRS 2016. Proceedings N2 - Electromicrobial engineering is an emerging, highly interdisciplinary research area linking bioprocesses with electrochemistry. In this work, microbial electrosynthesis (MES) of biobutanol is carried out during acetone-butanol-ethanol (ABE) fermentations with Clostridium acetobutylicum. A constant electric potential of −600mV (vs. Ag/AgCl) with simultaneous addition of the soluble redox mediator neutral red is used in order to study the electron transfer between the working electrode and the bacterial cells. The results show an earlier initiation of solvent production for all fermentations with applied potential compared to the conventional ABE fermentation. The f inal butanol concentration can be more than doubled by the application of a negative potential combined with addition of neutral red. Moreover a higher biofilm formation on the working electrode compared to control cultivations has been observed. In contrast to previous studies, our results also indicate that direct electron transfer (DET) might be possible with C. acetobutylicum. The presented results make microbial butanol production economically attractive and therefore support the development of sustainable production processes in the chemical industry aspired by the “Centre for resource-efficient chemistry and raw material change” as well as the the project “NanoKat” working on nanostructured catalysts in Kaiserslautern. Y1 - 2016 N1 - Young Researchers Symposium, YRS 2016, 14th - 15th April 2016, Fraunhofer-Zentrum Kaiserslautern SP - 49 EP - 53 PB - Fraunhofer Verlag CY - Karlsruhe ER - TY - JOUR A1 - Mathiak, Gerhard A1 - Plescher, Engelbert A1 - Willnecker, Rainer T1 - Liquid metal diffusion experiments in microgravity - Vibrational effects JF - Measurement science and technology Y1 - 2005 U6 - https://doi.org/10.1088/0957-0233/16/2/003 SN - 0957-0233 VL - Vol. 16 IS - No. 2 SP - 336 ER - TY - JOUR A1 - Ermelenko, Y. A1 - Yoshinobu, T. A1 - Mourzina, Y. A1 - Furuichi, K. A1 - Levichev, S. A1 - Vlasov, Y. A1 - Schöning, Michael Josef A1 - Iwasaki, H. T1 - Lithium sensor based on the laser scanning semiconductor transducer JF - Analytica Chimica Acta. 459 (2002), H. 1 Y1 - 2002 SN - 0378-4304 SP - 1 EP - 9 ER - TY - CHAP A1 - Bohrn, Ulrich A1 - Stütz, Evamaria A1 - Fleischer, Maximilian A1 - Schöning, Michael Josef A1 - Wagner, Patrick T1 - Living cell-based gas sensor system for the detection of acetone in air Y1 - 2012 SN - 978-3-9813484-2-2 U6 - https://doi.org/10.5162/IMCS2012/3.2.3 SP - 269 EP - 272 ER - TY - JOUR A1 - Heuermann, Holger A1 - Schiek, Burkhard T1 - LNN (Line-Network-Network): Verfahren zur Kalibrierung von Netzwerkanalysatoren JF - Kleinheubacher Berichte : Vorträge und Berichte der gemeinsamen Tagung des U.R.S.I.-Landesausschusses in der Bundesrepublik Deutschland / Hrsg.: Deutsche Telekom AG. 36. 1992 (1992) Y1 - 1992 SP - 327 EP - 335 ER - TY - JOUR A1 - Heuermann, Holger A1 - Schiek, Burkhard T1 - LNN( Line-Network-Network): The In-Fixture Calibration Procedure Y1 - 1993 N1 - XXIVth General Assembly of the International URSI, Kyoto SP - 149 EP - 149 ER - TY - JOUR A1 - Staat, Manfred A1 - Tran, Thanh Ngoc A1 - Kreißig, R. T1 - Load bearing capacity of thin shell structures made of elastoplastic material by direct methods JF - Technische Mechanik. 28 (2008), H. 3-4 Y1 - 2008 SP - 299 EP - 309 ER - TY - CHAP A1 - Uibel, Thomas A1 - Blaß, Hans Joachim T1 - Load Carrying Capacity of Joints with Dowel Type Fasteners in Solid Wood Panels T2 - Proceedings. CIB-W18 Meeting 2006, Florence, Italy 2006 Y1 - 2006 SN - 0945-6996 N1 - Paper 39-7-5 SP - 1 EP - 10 ER - TY - CHAP A1 - Dilthey, Ulrich A1 - Schleser, Markus A1 - Hegger, Josef A1 - Voss, Stefan ED - Reinhardt, Hans W. T1 - Load-bearing behaviour of polymer-impregnated textiles in concrete T2 - Fifth International Workshop on High Performance Fiber Reinforced Cement Composites (HPFRCC 5) : Mainz, July 10 - 13, 2007. (RILEM proceedings. 53) Y1 - 2007 SN - 978-2-35158-046-2 SP - 183 EP - 192 PB - RILEM Publ. CY - Bagneux ER - TY - JOUR A1 - Staat, Manfred T1 - Local and global collapse pressure of longitudinally flawed pipes and cylindrical vessels JF - International Journal of Pressure Vessels and Piping. 82 (2005), H. 3 Y1 - 2005 SN - 0308-0161 SP - 217 EP - 225 ER - TY - JOUR A1 - Orzada, Stephan A1 - Fiedler, Thomas M. A1 - Bitz, Andreas A1 - Ladd, Mark E. A1 - Quick, Harald H. T1 - Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance JF - Magnetic Resonance Materials in Physics, Biology and Medicine N2 - Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission. Y1 - 2020 SN - 1352-8661 U6 - https://doi.org/10.1007/s10334-020-00890-0 IS - 34 (2021) SP - 153 EP - 164 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Roeth, A.A. A1 - Slabu, I. A1 - Kessler, A. A1 - Engelmann, Ulrich M. T1 - Local treatment of pancreatic cancer with magnetic nanoparticles JF - HPB Y1 - 2019 U6 - https://doi.org/10.1016/j.hpb.2019.10.959 SN - 1365-182X VL - 21 IS - Supplement 3 SP - S868 EP - S869 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Prielmeier, Franz A1 - Hörstermann, D. A1 - Gyngell, M. L. A1 - Merboldt, K.-D. T1 - Localized Proton MRS of Acute and Chronic Gyperglycemia in Rat Brain in vivo / D. Hörstermann, F. Prielmeier , M. L. Gyngell, K.-D. Merboldt, W. Hänicke, J. Frahm JF - Book of Abstracts, SMRM, 11th Annual Meeting Berlin Y1 - 1992 N1 - Society of Magnetic Resonance in Medicine SP - 2740 ER - TY - CHAP A1 - Böhm, Stefan A1 - Hellmanns, Mark A1 - Backes, Andreas A1 - Dilger, Klaus T1 - Lock-in thermography based NDT of automotive parts T2 - Proceedings of the 3rd World Congress on Adhesion and Related Phenomena : WCARP-III, October 15 -18, 2006, Beijing, China Y1 - 2006 SP - 382 EP - 384 PB - Beijing Adhesion Society of China CY - Beijing ER - TY - JOUR A1 - Böhm, Stefan A1 - Hellmanns, Mark A1 - Backes, Andreas A1 - Dilger, Klaus T1 - Lock-in thermography based NDT of parts for the automotive industry JF - Journal of adhesion and interface Y1 - 2006 VL - Vol. 7 IS - No. 4 SP - 10 EP - 12 ER - TY - JOUR A1 - Förster, Arnold A1 - Janssen, G. A1 - Roer, T. G. van de T1 - Logic Circuits with reduced complexity based on devices with higher functionality / G. Janssen ; T. G. van de Roer ; W. Prost ... A. Förster JF - Proceedings / STW/SAFE 2nd Annual Workshop on Semiconductor Advances for Future Electronics, Safe '99 - ProRISC/IEEE 10th Annual Workshop on Circuits, Systems and Signal Processing, ProRISC 99 : November 24 - 26, 1999, Mierlo, The Netherlands [Elektronische Ressource] Y1 - 1999 N1 - SAFE <2, 1999, Mierlo> ; Workshop on Circuits, Systems and Signal Processing <10, 1999, Mierlo> ; Stichting voor de Technische Wetenschappen SP - 219 PB - Technology Foundation, STW CY - Utrecht ER - TY - JOUR A1 - Ferrein, Alexander T1 - Logic-based robot control in highly dynamic domains / Ferrein, Alexander ; Lakemeyer, Gerhard JF - Robotics and Autonomous Systems. 56 (2008), H. 11 Y1 - 2008 SN - 0921-8890 SP - 980 EP - 991 ER - TY - CHAP A1 - Tippkötter, Nils A1 - Möhring, Sophie A1 - Roth, Jasmine A1 - Wulfhorst, Helene T1 - Logistics of lignocellulosic feedstocks: preprocessing as a preferable option T2 - Biorefineries N2 - In comparison to crude oil, biorefinery raw materials are challenging in concerns of transport and storage. The plant raw materials are more voluminous, so that shredding and compacting usually are necessary before transport. These mechanical processes can have a negative influence on the subsequent biotechnological processing and shelf life of the raw materials. Various approaches and their effects on renewable raw materials are shown. In addition, aspects of decentralized pretreatment steps are discussed. Another important aspect of pretreatment is the varying composition of the raw materials depending on the growth conditions. This problem can be solved with advanced on-site spectrometric analysis of the material. KW - Analytics KW - Decentral KW - Mechanical KW - On-site KW - Pre-treatment Y1 - 2019 SN - 978-3-319-97117-9 SN - 978-3-319-97119-3 U6 - https://doi.org/10.1007/10_2017_58 N1 - Advances in biochemical engineering/biotechnology ; Vol. 166 SP - 43 EP - 68 PB - Springer CY - Cham ER - TY - JOUR A1 - Fredebeul-Krein, Markus A1 - Knoben, Werner T1 - Long term risk sharing contracts as an approach to establish public–private partnerships for investment into next generation access networks JF - Telecommunications Policy Y1 - 2010 SN - 0308-5961 VL - 34 IS - 9 SP - 528 EP - 539 ER - TY - JOUR A1 - Enning, Manfred A1 - Zambou, Nathan A1 - Abel, Dirk T1 - Longitudinal Control of Following Vehicles within Platoon : A Model-Based Predictive Approach / Zambou, N. ; Enning, M. ; Abel, D. JF - Advances in automotive control 2004 : a proceedings volume from the IFAC symposium, Salerno, Italy, 19 - 23 April 2004 / ed. C. Pianese Y1 - 2005 SN - 0080442501 N1 - International Federation of Automatic Control ; Symposium on Advances in Automotive Control ; (4, 2004, Salerno) SP - 733 EP - 738 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Ferrein, Alexander A1 - Steinbauer, Gerald T1 - Looking back on 20 Years of RoboCup JF - KI - Künstliche Intelligenz Y1 - 2016 U6 - https://doi.org/10.1007/s13218-016-0443-y SN - 1610-1987 VL - 30 IS - 3-4 SP - 321 EP - 323 PB - Springer CY - Berlin ER - TY - JOUR A1 - Hagemann, Hans-Jürgen T1 - Loss mechanisms and domain stabilization in doped BaTiO₃ JF - Journal of Physics C: Solid State Physics Y1 - 1978 SN - 0022-3719 U6 - https://doi.org/10.1088/0022-3719/11/15/031 VL - 11 IS - 15 SP - 3333 EP - 3344 PB - n.a. CY - London ER - TY - CHAP A1 - Anthrakidis, Anette A1 - Rusack, Markus A1 - Schwarzer, Klemens T1 - Low effort measurement method of PTC-efficiency T2 - SolarPACES 2010 : the CSP conference: electricity, fuels and clean water from concentrated solar energy ; 21 to 24 September 2010, Perpignan, France Y1 - 2010 SP - 48 EP - 49 PB - Soc. OSC CY - Saint Maur ER - TY - JOUR A1 - Gasparyan, F. V. A1 - Poghossian, Arshak A1 - Vitusevich, S. A. A1 - Petrychuk, M. V. A1 - Sydoruk, V. A. A1 - Surmalyan, A. V. A1 - Siqueira, J. R. A1 - Oliveira, O. N. A1 - Offenhäusser, A. A1 - Schöning, Michael Josef T1 - Low Frequency Noise In Electrolyte-Gate Field-Effect Devices Functionalized With Dendrimer/Carbon-Nanotube Multilayers JF - Noise and fluctuations : 20th International Conference on Noise and Fluctuations, ICNF 2009, Pisa, Italy, 14 - 19 June 2009 / ed. Massimo Macucci; Giovanni Basso Y1 - 2009 SN - 9780735406650 N1 - AIP conference proceedings ; 1129 ; International Conference on Noise and Fluctuations ; (20, 2009, Pisa) SP - 133 EP - 136 PB - American Inst. of Physics CY - Melville, NY ER - TY - JOUR 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 JF - 5th International Gas Turbine Conference ETN-IGTC, ETN-2010-42, Brussels, Belgium, October 2010 Y1 - 2010 ER - TY - CHAP A1 - Funke, Harald A1 - Börner, Sebastian A1 - Keinz, Jan A1 - Hendrick, P. A1 - Recker, E. T1 - Low NOx Hydrogen combustion chamber for industrial gas turbine applications“, 14th International Symposium on Transport Phenomena and Dynamics of Rotating Machinery T2 - ISROMAC-14 : the Forteenth International Symposium on Transport Phenomena and Dynamics of Rotating Machinery ; Honolulu, Hawaii, February 27 - March 02nd, 2012 Y1 - 2012 N1 - International Symposium on Transport Phenomena and Dynamics of Rotating Machinery ; (14 ; 2012.02.27-03.02 ; Honolulu, Hawaii) ER - TY - JOUR A1 - Gasparyan, Ferdinand V. A1 - Poghossian, Arshak A1 - Vitusevich, Svetlana A. A1 - Petrychuk, Mykhaylo V. A1 - Sydoruk, Viktor A. A1 - Siqueira, José R. Jr. A1 - Oliveira, Osvaldo N. Jr. A1 - Offenhäusser, Andreas A1 - Schöning, Michael Josef T1 - Low-Frequency Noise in Field-Effect Devices Functionalized With Dendrimer/Carbon-Nanotube Multilayers JF - IEEE Sensors Journal. 11 (2011), H. 1 Y1 - 2011 SN - 1530-437X SP - 142 EP - 149 PB - IEEE CY - New York ER - TY - JOUR A1 - Akimbekov, Nuraly S. A1 - Digel, Ilya A1 - Tastambek, Kuanysh T. A1 - Sherelkhan, Dinara K. A1 - Jussupova, Dariya B. A1 - Altynbay, Nazym P. T1 - Low-rank coal as a source of humic substances for soil amendment and fertility management JF - Agriculture N2 - Humic substances (HS), as important environmental components, are essential to soil health and agricultural sustainability. The usage of low-rank coal (LRC) for energy generation has declined considerably due to the growing popularity of renewable energy sources and gas. However, their potential as soil amendment aimed to maintain soil quality and productivity deserves more recognition. LRC, a highly heterogeneous material in nature, contains large quantities of HS and may effectively help to restore the physicochemical, biological, and ecological functionality of soil. Multiple emerging studies support the view that LRC and its derivatives can positively impact the soil microclimate, nutrient status, and organic matter turnover. Moreover, the phytotoxic effects of some pollutants can be reduced by subsequent LRC application. Broad geographical availability, relatively low cost, and good technical applicability of LRC offer the advantage of easy fulfilling soil amendment and conditioner requirements worldwide. This review analyzes and emphasizes the potential of LRC and its numerous forms/combinations for soil amelioration and crop production. A great benefit would be a systematic investment strategy implicating safe utilization and long-term application of LRC for sustainable agricultural production. KW - soil remediation KW - crop yield KW - soil health KW - soil amendment KW - low-rank coal Y1 - 2021 U6 - https://doi.org/10.3390/agriculture11121261 SN - 2077-0472 N1 - This article belongs to the Special Issue "From Waste to Fertilizer in Sustainable Agriculture" VL - 11 IS - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Förster, Arnold A1 - Mikulics, M. A1 - Marso, M. A1 - Adam, R. T1 - Low-temperature-grown MBE GaAs for terahertz photomixers. Mikulics, M.; Marso, M.; Adam, R.; Fox, A.; Buca, D.; Förster, A.; Kordos, P.; Xu, Y.; Sobolewski, R. JF - 2001 Symposium on Electron Devices for Microwave and Optoelectronic Applications ; [Vienna University of Technology, Institute of Electrical Measurements and Circuit Design, 15 - 16 November 2001, Vienna, Austria ; proceedings] / EDMO 2001. Organised by: Institute of Electrical Measurements and Circuit Design, Vienna University of Technology, Austria. With technical co-sponsorship from IEEE Electron Devices Society Y1 - 2001 SN - 078037049X N1 - IEEE catalog number: 01TH8567 SP - 155 EP - 155 PB - IEEE Operations Center CY - Piscataway, NJ ER - TY - JOUR A1 - Dachwald, Bernd A1 - Carnelli, I. A1 - Vasile, M. T1 - Low-Thrust Gravity Assist Trajectory Optimization Using Evolutionary Neurocontrollers / I. Carnelli ; B. Dachwald ; M. Vasile ... JF - Astrodynamics 2005 : proceedings of the AAS/AIAA astrodynamics conference held August 7 - 11, 2005, South Lake Tahoe, California / ed. by Bobby G. Williams. - Pt. 3. - (Advances in the astronautical sciences ; 123,3) Y1 - 2006 SN - 0-87703-527-X N1 - Astrodynamics Conference <2005, South Lake Tahoe, Calif.> ; American Astronautical Society ; Number: AAS-05-374 SP - 1911 EP - 1928 PB - Univelt CY - San Diego, Calif. ER - TY - CHAP A1 - Dachwald, Bernd T1 - Low-Thrust Mission Analysis and Global Trajectory Optimization Using Evolutionary Neurocontrol: New Results T2 - European Workshop on Space Mission Analysis ESA/ESOC, Darmstadt, Germany 10 { 12 Dec 2007 N2 - Interplanetary trajectories for low-thrust spacecraft are often characterized by multiple revolutions around the sun. Unfortunately, the convergence of traditional trajectory optimizers that are based on numerical optimal control methods depends strongly on an adequate initial guess for the control function (if a direct method is used) or for the starting values of the adjoint vector (if an indirect method is used). Especially when many revolutions around the sun are re- quired, trajectory optimization becomes a very difficult and time-consuming task that involves a lot of experience and expert knowledge in astrodynamics and optimal control theory, because an adequate initial guess is extremely hard to find. Evolutionary neurocontrol (ENC) was proposed as a smart method for low-thrust trajectory optimization that fuses artificial neural networks and evolutionary algorithms to so-called evolutionary neurocontrollers (ENCs) [1]. Inspired by natural archetypes, ENC attacks the trajectoryoptimization problem from the perspective of artificial intelligence and machine learning, a perspective that is quite different from that of optimal control theory. Within the context of ENC, a trajectory is regarded as the result of a spacecraft steering strategy that maps permanently the actual spacecraft state and the actual target state onto the actual spacecraft control vector. This way, the problem of searching the optimal spacecraft trajectory is equivalent to the problem of searching (or "learning") the optimal spacecraft steering strategy. An artificial neural network is used to implement such a spacecraft steering strategy. It can be regarded as a parameterized function (the network function) that is defined by the internal network parameters. Therefore, each distinct set of network parameters defines a different network function and thus a different steering strategy. The problem of searching the optimal steering strategy is now equivalent to the problem of searching the optimal set of network parameters. Evolutionary algorithms that work on a population of (artificial) chromosomes are used to find the optimal network parameters, because the parameters can be easily mapped onto a chromosome. The trajectory optimization problem is solved when the optimal chromosome is found. A comparison of solar sail trajectories that have been published by others [2, 3, 4, 5] with ENC-trajectories has shown that ENCs can be successfully applied for near-globally optimal spacecraft control [1, 6] and that they are able to find trajectories that are closer to the (unknown) global optimum, because they explore the trajectory search space more exhaustively than a human expert can do. The obtained trajectories are fairly accurate with respect to the terminal constraint. If a more accurate trajectory is required, the ENC-solution can be used as an initial guess for a local trajectory optimization method. Using ENC, low-thrust trajectories can be optimized without an initial guess and without expert attendance. Here, new results for nuclear electric spacecraft and for solar sail spacecraft are presented and it will be shown that ENCs find very good trajectories even for very difficult problems. Trajectory optimization results are presented for 1. NASA's Solar Polar Imager Mission, a mission to attain a highly inclined close solar orbit with a solar sail [7] 2. a mission to de ect asteroid Apophis with a solar sail from a retrograde orbit with a very-high velocity impact [8, 9] 3. JPL's \2nd Global Trajectory Optimization Competition", a grand tour to visit four asteroids from different classes with a NEP spacecraft Y1 - 2007 ER - TY - JOUR A1 - Dachwald, Bernd T1 - Low-Thrust Trajectory Optimization and Interplanetary Mission Analysis Using Evolutionary Neurocontrol JF - Deutscher Luft- und Raumfahrtkongress 2004 : Dresden, 20. bis 23. September 2004, Motto: Luft- und Raumfahrt - Brücke für eine wissensbasierte Gesellschaft / Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth e.V. (DGLR). [Red.: Peter Brandt (verantwortlich)]. - Bd. 2. - (Jahrbuch ... der Deutschen Gesellschaft für Luft- und Raumfahrt) Y1 - 2004 N1 - Deutscher Luft- und Raumfahrt-Kongress <2004, Dresden> ; Deutsche Gesellschaft für Luft- und Raumfahrt - Lilienthal-Oberth ; DGLR-2004-116 SP - 917 EP - 926 CY - Bonn ER - TY - CHAP A1 - Becker, Tim A1 - Bragard, Michael T1 - Low-Voltage DC Training Lab for Electric Drives - Optimizing the Balancing Act Between High Student Throughput and Individual Learning Speed T2 - 2024 IEEE Global Engineering Education Conference (EDUCON) N2 - After a brief introduction of conventional laboratory structures, this work focuses on an innovative and universal approach for a setup of a training laboratory for electric machines and drive systems. The novel approach employs a central 48 V DC bus, which forms the backbone of the structure. Several sets of DC machine, asynchronous machine and synchronous machine are connected to this bus. The advantages of the novel system structure are manifold, both from a didactic and a technical point of view: Student groups can work on their own performance level in a highly parallelized and at the same time individualized way. Additional training setups (similar or different) can easily be added. Only the total power dissipation has to be provided, i.e. the DC bus balances the power flow between the student groups. Comparative results of course evaluations of several cohorts of students are shown. KW - Synchronous machines KW - Power dissipation KW - Throughput KW - Low voltage KW - DC machines KW - Manifolds KW - Training Y1 - 2024 U6 - https://doi.org/10.1109/EDUCON60312.2024.10578902 SN - 2165-9559 SN - 2165-9567 (eISSN) N1 - 2024 IEEE Global Engineering Education Conference (EDUCON), 08-11 May 2024, Kos Island, Greece PB - IEEE CY - New York, NY ER - TY - JOUR A1 - Hellwig, Angelika A1 - Volkmann, Lutz T1 - Lower bounds on the vertex-connectivity of digraphs and graphs JF - Information processing letters Y1 - 2006 SN - 1872-6119 (E-Journal); 0020-0190 (Print) VL - Vol. 99 IS - Iss. 2 SP - 41 EP - 46 ER - TY - JOUR A1 - Karamanidis, Kiros A1 - Albracht, Kirsten A1 - Braunstein, Bjoern A1 - Catala, Maria Moreno A1 - Goldmann, Jan-Peter A1 - Brüggemann, Gert-Peter T1 - Lower leg musculoskeletal geometry and sprint performance JF - Gait and Posture N2 - The purpose of this study was to investigate whether sprint performance is related to lower leg musculoskeletal geometry within a homogeneous group of highly trained 100-m sprinters. Using a cluster analysis, eighteen male sprinters were divided into two groups based on their personal best (fast: N = 11, 10.30 ± 0.07 s; slow: N = 7, 10.70 ± 0.08 s). Calf muscular fascicle arrangement and Achilles tendon moment arms (calculated by the gradient of tendon excursion versus ankle joint angle) were analyzed for each athlete using ultrasonography. Achilles tendon moment arm, foot and ankle skeletal geometry, fascicle arrangement as well as the ratio of fascicle length to Achilles tendon moment arm showed no significant (p > 0.05) correlation with sprint performance, nor were there any differences in the analyzed musculoskeletal parameters between the fast and slow sprinter group. Our findings provide evidence that differences in sprint ability in world-class athletes are not a result of differences in the geometrical design of the lower leg even when considering both skeletal and muscular components. Y1 - 2011 U6 - https://doi.org/10.1016/j.gaitpost.2011.03.009 SN - 0966-6362 VL - 34 IS - 1 SP - 138 EP - 141 PB - Elsevier CY - Amsterdam ER -