@article{BlankeHagenkampDoeringetal.2021, author = {Blanke, Tobias and Hagenkamp, Markus and D{\"o}ring, Bernd and G{\"o}ttsche, Joachim and Reger, Vitali and Kuhnhenne, Markus}, title = {Net-exergetic, hydraulic and thermal optimization of coaxial heat exchangers using fixed flow conditions instead of fixed flow rates}, series = {Geothermal Energy}, volume = {9}, journal = {Geothermal Energy}, number = {Article number: 19}, publisher = {Springer}, address = {Berlin}, issn = {2195-9706}, doi = {10.1186/s40517-021-00201-3}, pages = {23 Seiten}, year = {2021}, abstract = {Previous studies optimized the dimensions of coaxial heat exchangers using constant mass fow rates as a boundary condition. They show a thermal optimal circular ring width of nearly zero. Hydraulically optimal is an inner to outer pipe radius ratio of 0.65 for turbulent and 0.68 for laminar fow types. In contrast, in this study, fow conditions in the circular ring are kept constant (a set of fxed Reynolds numbers) during optimization. This approach ensures fxed fow conditions and prevents inappropriately high or low mass fow rates. The optimization is carried out for three objectives: Maximum energy gain, minimum hydraulic efort and eventually optimum net-exergy balance. The optimization changes the inner pipe radius and mass fow rate but not the Reynolds number of the circular ring. The thermal calculations base on Hellstr{\"o}m's borehole resistance and the hydraulic optimization on individually calculated linear loss of head coefcients. Increasing the inner pipe radius results in decreased hydraulic losses in the inner pipe but increased losses in the circular ring. The net-exergy diference is a key performance indicator and combines thermal and hydraulic calculations. It is the difference between thermal exergy fux and hydraulic efort. The Reynolds number in the circular ring is instead of the mass fow rate constant during all optimizations. The result from a thermal perspective is an optimal width of the circular ring of nearly zero. The hydraulically optimal inner pipe radius is 54\% of the outer pipe radius for laminar fow and 60\% for turbulent fow scenarios. Net-exergetic optimization shows a predominant infuence of hydraulic losses, especially for small temperature gains. The exact result depends on the earth's thermal properties and the fow type. Conclusively, coaxial geothermal probes' design should focus on the hydraulic optimum and take the thermal optimum as a secondary criterion due to the dominating hydraulics.}, language = {en} } @article{Pieper2011, author = {Pieper, Martin}, title = {Multiobjective optimization with expensive objectives applied to a thermodynamic material design problem}, series = {Proceedings in applied mathematics and mechanics : PAMM. 11 (2011), H. 1}, journal = {Proceedings in applied mathematics and mechanics : PAMM. 11 (2011), H. 1}, publisher = {Wiley}, address = {Weinheim}, isbn = {1617-7061}, pages = {733 -- 734}, year = {2011}, language = {en} } @article{GoettscheAlexopoulosDuemmleretal.2019, author = {G{\"o}ttsche, Joachim and Alexopoulos, Spiros and D{\"u}mmler, Andreas and Maddineni, S. K.}, title = {Multi-Mirror Array Calculations With Optical Error}, pages = {1 -- 6}, year = {2019}, abstract = {The optical performance of a 2-axis solar concentrator was simulated with the COMSOL Multiphysics® software. The concentrator consists of a mirror array, which was created using the application builder. The mirror facets are preconfigured to form a focal point. During tracking all mirrors are moved simultaneously in a coupled mode by 2 motors in two axes, in order to keep the system in focus with the moving sun. Optical errors on each reflecting surface were implemented in combination with the solar angular cone of ± 4.65 mrad. As a result, the intercept factor of solar radiation that is available to the receiver was calculated as a function of the transversal and longitudinal angles of incidence. In addition, the intensity distribution on the receiver plane was calculated as a function of the incidence angles.}, language = {en} } @article{FoersterTillmannGerthsen1995, author = {F{\"o}rster, Arnold and Tillmann, K. and Gerthsen, D.}, title = {Morphological transformations of MBE-grown In0.6Ga0.4As island on GaAs(001) substrates / K. Tillmann ; D. Gerthsen ; P. Pfundstein ; A. F{\"o}rster ...}, series = {Microscopy of semiconducting materials 1995 : proceedings of the Institute of Physics Conference held at Oxford University, 20 - 23 March 1995 / Ed. by A G Cullis ... - (Conference series / Institute of Physics ; 146)}, journal = {Microscopy of semiconducting materials 1995 : proceedings of the Institute of Physics Conference held at Oxford University, 20 - 23 March 1995 / Ed. by A G Cullis ... - (Conference series / Institute of Physics ; 146)}, publisher = {Institute of Physics}, address = {Bristol [u.a.]}, isbn = {0-7503-0347-6}, pages = {195 -- ff.}, year = {1995}, language = {en} } @article{RossiWinandsButenweg2022, author = {Rossi, Leonardo and Winands, Mark H. M. and Butenweg, Christoph}, title = {Monte Carlo Tree Search as an intelligent search tool in structural design problems}, series = {Engineering with Computers : An International Journal for Simulation-Based Engineering}, volume = {38}, journal = {Engineering with Computers : An International Journal for Simulation-Based Engineering}, number = {4}, editor = {Zhang, Jessica}, publisher = {Springer Nature}, address = {Cham}, issn = {1435-5663}, doi = {10.1007/s00366-021-01338-2}, pages = {3219 -- 3236}, year = {2022}, abstract = {Monte Carlo Tree Search (MCTS) is a search technique that in the last decade emerged as a major breakthrough for Artificial Intelligence applications regarding board- and video-games. In 2016, AlphaGo, an MCTS-based software agent, outperformed the human world champion of the board game Go. This game was for long considered almost infeasible for machines, due to its immense search space and the need for a long-term strategy. Since this historical success, MCTS is considered as an effective new approach for many other scientific and technical problems. Interestingly, civil structural engineering, as a discipline, offers many tasks whose solution may benefit from intelligent search and in particular from adopting MCTS as a search tool. In this work, we show how MCTS can be adapted to search for suitable solutions of a structural engineering design problem. The problem consists of choosing the load-bearing elements in a reference reinforced concrete structure, so to achieve a set of specific dynamic characteristics. In the paper, we report the results obtained by applying both a plain and a hybrid version of single-agent MCTS. The hybrid approach consists of an integration of both MCTS and classic Genetic Algorithm (GA), the latter also serving as a term of comparison for the results. The study's outcomes may open new perspectives for the adoption of MCTS as a design tool for civil engineers.}, language = {en} } @article{FoersterZettlerMikkelsenetal.1992, author = {F{\"o}rster, Arnold and Zettler, J.-T. and Mikkelsen, H. and Leo, K.}, title = {Modulated ellipsometric measurements and transfer-matrix calculation of the field-dependent dielectric function of a multiple quantum well / J.-Th. Zettler ; H. Mikkelsen ; K. Leo ... A. F{\"o}rster}, series = {Physical Review B . 46 (1992), H. 24}, journal = {Physical Review B . 46 (1992), H. 24}, isbn = {0163-1829}, pages = {15955 -- 15962}, year = {1992}, language = {en} } @article{MistlerButenwegMeskouris2006, author = {Mistler, Michael and Butenweg, Christoph and Meskouris, Konstantin}, title = {Modelling methods of historic masonry buildings under seismic excitation}, series = {Journal of seismology}, volume = {Volume 10}, journal = {Journal of seismology}, number = {No. 4}, issn = {1383-4649 (Print) ; 1573-157X (E-Journal)}, doi = {10.1007/s10950-006-9033-z}, pages = {497 -- 510}, year = {2006}, language = {en} } @article{VogtIwanowskiStrahserMarquartetal.2013, author = {Vogt, Christian and Iwanowski-Strahser, Katha and Marquart, Gabriele and Arnold, Juliane and Mottaghy, Darius and Pechnig, Renate and Gnjezda, Daniel and Clauser, Christoph}, title = {Modeling contribution to risk assessment of thermal production power for geothermal reservoirs}, series = {Renewable Energy}, volume = {53}, journal = {Renewable Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0960-1481}, doi = {10.1016/j.renene.2012.11.026}, pages = {230 -- 241}, year = {2013}, language = {en} } @article{RiekeStollenwerkDahmenetal.2018, author = {Rieke, Christian and Stollenwerk, Dominik and Dahmen, Markus and Pieper, Martin}, title = {Modeling and optimization of a biogas plant for a demand-driven energy supply}, series = {Energy}, volume = {145}, journal = {Energy}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0360-5442}, doi = {10.1016/j.energy.2017.12.073}, pages = {657 -- 664}, year = {2018}, abstract = {Due to the Renewable Energy Act, in Germany it is planned to increase the amount of renewable energy carriers up to 60\%. One of the main problems is the fluctuating supply of wind and solar energy. Here biogas plants provide a solution, because a demand-driven supply is possible. Before running such a plant, it is necessary to simulate and optimize the process. This paper provides a new model of a biogas plant, which is as accurate as the standard ADM1 model. The advantage compared to ADM1 is that it is based on only four parameters compared to 28. Applying this model, an optimization was installed, which allows a demand-driven supply by biogas plants. Finally the results are confirmed by several experiments and measurements with a real test plant.}, language = {en} } @article{FoersterZamdmerHuetal.1999, author = {F{\"o}rster, Arnold and Zamdmer, N. and Hu, Qing and Verghese, S.}, title = {Mode-Discriminating Photoconductor and Coplanar Wave-Guide Circuits for Picosecond Sampling. Zamdmer, N.; Hu, Qing ; Verghese, S. ; F{\"o}rster, A.}, series = {Applied Physics Letters. 74 (1999), H. 7}, journal = {Applied Physics Letters. 74 (1999), H. 7}, isbn = {1077-3118}, pages = {1039 -- 1041}, year = {1999}, language = {en} } @article{FoersterDiekerGerthsen1993, author = {F{\"o}rster, Arnold and Dieker, C. and Gerthsen, D.}, title = {Microstructure of the AlAs/GaAs and AlAs/InGaAs resonant tunneling diodes and its correlation with the electrical properties / C. Dieker ; D. Gerthsen ; A. F{\"o}rster ...}, series = {Microscopy of semiconducting materials 1993 : proceedings of the Royal Microscopical Society Conference held at Oxford University, 5 - 8 April 1993 / ed. by A. G. Cullis ... - (Conference series / Institute of Physics ; 134)}, journal = {Microscopy of semiconducting materials 1993 : proceedings of the Royal Microscopical Society Conference held at Oxford University, 5 - 8 April 1993 / ed. by A. G. Cullis ... - (Conference series / Institute of Physics ; 134)}, publisher = {Institute of Physics}, address = {Bristol [u.a.]}, isbn = {0-7503-0290-9}, pages = {253 -- ff.}, year = {1993}, language = {en} } @article{Hoyler1985, author = {Hoyler, Friedrich}, title = {Microscopic and semimicroscopic analysis of the reaction 27al- (p,\#ga)24mg in the energy range between 20 and 45 mev}, series = {Physical review / C, nuclear physics. 31 (1985), H. 1}, journal = {Physical review / C, nuclear physics. 31 (1985), H. 1}, isbn = {0556-2813}, pages = {17}, year = {1985}, language = {en} } @article{SchmidtTonnesmannFoersteretal.2000, author = {Schmidt, R. and Tonnesmann, A. and F{\"o}rster, Arnold and Grimm, M. and Kordos, P. and L{\"u}th, H.}, title = {Metamorphic InAlAs/InGaAs HEMT's on GaAs substrates using an InP buffer layer}, series = {8th IEEE International Symposium on High Performance Electron Devices for Microwave and Optoelectronic Applications : EDMO 2000 ; [13 - 14 November 2000, University of Glasgow] / organised by Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow Scotland. MTT/ED/AP/LEO Societies Joint Chapter, United Kingdom and Republic of Ireland Section. With technical co-sponsorship from IEEE Electron Device Society}, journal = {8th IEEE International Symposium on High Performance Electron Devices for Microwave and Optoelectronic Applications : EDMO 2000 ; [13 - 14 November 2000, University of Glasgow] / organised by Department of Electronics and Electrical Engineering, University of Glasgow, Glasgow Scotland. MTT/ED/AP/LEO Societies Joint Chapter, United Kingdom and Republic of Ireland Section. With technical co-sponsorship from IEEE Electron Device Society}, publisher = {IEEE Operations Center}, address = {Piscataway, NJ}, isbn = {0-7803-6550-X}, pages = {95 -- 98}, year = {2000}, language = {en} } @article{KernZischank1988, author = {Kern, Alexander and Zischank, Wolfgang J.}, title = {Melting effects on metal sheets and air termination wires caused by direct lightning strikes}, series = {Conference proceedings : Graz, {\"O}sterreich, 25. - 29. April 1988 / Gesamtorganisation: {\"O}sterr. Verb. f{\"u}r Elektrotechnik ({\"O}VE), Fachausschuß Blitzschutz ... [Red.: G. Diendorfer ...]}, journal = {Conference proceedings : Graz, {\"O}sterreich, 25. - 29. April 1988 / Gesamtorganisation: {\"O}sterr. Verb. f{\"u}r Elektrotechnik ({\"O}VE), Fachausschuß Blitzschutz ... [Red.: G. Diendorfer ...]}, publisher = {Eigenverl. des {\"O}VE}, address = {Wien}, isbn = {3-85133-001-3}, year = {1988}, language = {en} } @article{Helsper1986, author = {Helsper, Christoph}, title = {Measurement Techniques For Ultrafine Particles}, series = {Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986}, journal = {Ultrafine aerosols. Properties and behaviour. Proceedings of the 1. International Workshop on Ultrafine Aerosols of the Sonderforschungsbereich 209 'Stoff- und Energietransport in Aerosolen' -'Mass and energy transfer in aerosols'-, held at the Univ. of Duisburg on Sept. 29, 1986}, address = {Duisburg}, year = {1986}, language = {en} } @article{ButenwegMarinkovicKubalskietal.2016, author = {Butenweg, Christoph and Marinkovic, Marko and Kubalski, Thomas and Klinkel, Sven}, title = {Masonry infilled reinforced concrete frames under horizontal loading}, series = {Mauerwerk}, volume = {20}, journal = {Mauerwerk}, number = {4}, publisher = {Ernst \& Sohn}, address = {Berlin}, issn = {1437-1022}, doi = {10.1002/dama.201600703}, pages = {305 -- 312}, year = {2016}, abstract = {The behaviour of infilled reinforced concrete frames under horizontal load has been widely investigated, both experimentally and numerically. Since experimental tests represent large investments, numerical simulations offer an efficient approach for a more comprehensive analysis. When RC frames with masonry infill walls are subjected to horizontal loading, their behaviour is highly non-linear after a certain limit, which makes their analysis quite difficult. The non-linear behaviour results from the complex inelastic material properties of the concrete, infill wall and conditions at the wall-frame interface. In order to investigate this non-linear behaviour in detail, a finite element model using a micro modelling approach is developed, which is able to predict the complex non-linear behaviour resulting from the different materials and their interaction. Concrete and bricks are represented by a non-linear material model, while each reinforcement bar is represented as an individual part installed in the concrete part and behaving elasto-plastically. Each brick is modelled individually and connected taking into account the non-linearity of a brick mortar interface. The same approach is followed using two finite element software packages and the results are compared with the experimental results. The numerical models show a good agreement with the experiments in predicting the overall behaviour, but also very good matching for strength capacity and drift. The results emphasize the quality and the valuable contribution of the numerical models for use in parametric studies, which are needed for the derivation of design recommendations for infilled frame structures.}, language = {en} } @article{HellmannsBoehmDilger2006, author = {Hellmanns, Mark and B{\"o}hm, Stefan and Dilger, Klaus}, title = {Manual applications of adhesives}, series = {Journal of adhesion and interface}, volume = {Vol. 7}, journal = {Journal of adhesion and interface}, number = {No. 4}, pages = {24 -- 27}, year = {2006}, language = {en} } @article{BechstedtHaasHackeretal.1985, author = {Bechstedt, U. and Haas, H. and Hacker, U. and Hardt, Arno and Henn, K. and Martin, S. and Wimmer, J.}, title = {Magnets for the German Spallation Source SNQ}, series = {IEEE transactions on nuclear science. Vol. 32, iss. 5}, journal = {IEEE transactions on nuclear science. Vol. 32, iss. 5}, issn = {1558-1578 (E-Journal); 0018-9499 (Print)}, pages = {3631 -- 3633}, year = {1985}, language = {en} } @article{FoersterBetkoMorvicetal.1999, author = {F{\"o}rster, Arnold and Betko, J. and Morvic, M. and Novak, J.}, title = {Magnetoresistance in low-temperature grown molecular-beam epitaxial GaAs. Betko, J.; Morvic, M.; Novak, J.; F{\"o}rster, A.; Kordos, P.}, series = {Journal of Applied Physics. 86 (1999), H. 11}, journal = {Journal of Applied Physics. 86 (1999), H. 11}, isbn = {1089-7550}, pages = {6243 -- 6248}, year = {1999}, language = {en} } @article{FoersterMikulicsMarsoetal.2001, author = {F{\"o}rster, Arnold and Mikulics, M. and Marso, M. and Adam, R.}, title = {Low-temperature-grown MBE GaAs for terahertz photomixers. Mikulics, M.; Marso, M.; Adam, R.; Fox, A.; Buca, D.; F{\"o}rster, A.; Kordos, P.; Xu, Y.; Sobolewski, R.}, series = {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}, journal = {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}, publisher = {IEEE Operations Center}, address = {Piscataway, NJ}, isbn = {078037049X}, pages = {155 -- 155}, year = {2001}, language = {en} }