@article{PieperKlein2011, author = {Pieper, Martin and Klein, Peter}, title = {A simple and accurate numerical network flow model for bionic micro heat exchangers}, series = {Heat mass transfer}, volume = {47}, journal = {Heat mass transfer}, number = {5}, publisher = {Springer}, address = {Berlin}, isbn = {0947-7411}, pages = {491 -- 503}, year = {2011}, language = {en} } @article{PieperKlein2012, author = {Pieper, Martin and Klein, Peter}, title = {Application of simple, periodic homogenization techniques to non-linear heat conduction problems in non-periodic, porous media}, series = {Heat mass transfer}, volume = {48}, journal = {Heat mass transfer}, number = {2}, publisher = {Springer}, address = {Berlin}, issn = {0947-7411}, doi = {10.1007/s00231-011-0879-4}, pages = {291 -- 300}, year = {2012}, abstract = {Often, detailed simulations of heat conduction in complicated, porous media have large runtimes. Then homogenization is a powerful tool to speed up the calculations by preserving accurate solutions at the same time. Unfortunately real structures are generally non-periodic, which requires unpractical, complicated homogenization techniques. We demonstrate in this paper, that the application of simple, periodic techniques to realistic media, that are just close to periodic, gives accurate, approximative solutions. In order to obtain effective parameters for the homogenized heat equation, we have to solve a so called "cell problem". In contrast to periodic structures it is not trivial to determine a suitable unit cell, which represents a non-periodic media. To overcome this problem, we give a rule of thumb on how to choose a good cell. Finally we demonstrate the efficiency of our method for virtually generated foams as well as real foams and compare these results to periodic structures.}, language = {en} } @article{PieperKlein2010, author = {Pieper, Martin and Klein, Peter}, title = {Numerical solution of the heat equation with non-linear, time derivative-dependent source term}, series = {International Journal for Numerical Methods in Engineering}, volume = {84}, journal = {International Journal for Numerical Methods in Engineering}, number = {10}, publisher = {Wiley}, address = {Chichester}, issn = {0029-5981}, doi = {10.1002/nme.2937}, pages = {1205 -- 1221}, year = {2010}, abstract = {The mathematical modeling of heat conduction with adsorption effects in coated metal structures yields the heat equation with piecewise smooth coefficients and a new kind of source term. This term is special, because it is non-linear and furthermore depends on a time derivative. In our approach we reformulated this as a new problem for the usual heat equation, without source term but with a new non-linear coefficient. We gave an existence and uniqueness proof for the weak solution of the reformulated problem. To obtain a numerical solution, we developed a semi-implicit and a fully implicit finite volume method. We compared these two methods theoretically as well as numerically. Finally, as practical application, we simulated the heat conduction in coated aluminum fibers with adsorption in the zeolite coating. Copyright © 2010 John Wiley \& Sons, Ltd.}, language = {en} } @inproceedings{PieperSchulz2014, author = {Pieper, Martin and Schulz, Silvia}, title = {Teaching Simulation Methods with COMSOL Multiphysics}, organization = {COMSOL Conference <2014, Cambridge>}, pages = {7}, year = {2014}, abstract = {This paper describes two courses on simulation methods for graduate students: "Simulation Methods" and "Simulation and Optimization in Virtual Engineering" The courses were planned to teach young engineers how to work with simulation software as well as to understand the necessary mathematical background. As simulation software COMSOL is used. The main philosophy was to combine theory and praxis in a way that motivates the students. In addition "soft skills" should be improved. This was achieved by project work as final examination. As underlying didactical principle the ideas of Bloom's revised taxonomy were followed. The paper basically focusses on educational aspects, e.g. how to structure the course, plan the exercises, organize the project work and include practical COMSOL examples.}, language = {en} } @misc{PierHummenStellberg1996, author = {Pier, Arnold and Hummen, J{\"o}rg and Stellberg, Michael}, title = {Surgical clip applicator}, pages = {16, 7, 2 S. : graph. Darst.}, year = {1996}, language = {en} } @inproceedings{PuetzBaierBrauneretal.2022, author = {P{\"u}tz, Sebastian and Baier, Ralph and Brauner, Philipp and Brillowski, Florian and Dammers, Hannah and Liehner, Luca and Mertens, Alexander and Rodemann, Niklas and Schneider, Sebastian and Schollemann, Alexander and Steuer-Dankert, Linda and Vervier, Luisa and Gries, Thomas and Leicht-Scholten, Carmen and Nagel, Saskia K. and Piller, Frank T. and Schuh, G{\"u}nther and Ziefle, Martina and Nitsch, Verena}, title = {An interdisciplinary view on humane interfaces for digital shadows in the internet of production}, series = {2022 15th International Conference on Human System Interaction (HSI)}, booktitle = {2022 15th International Conference on Human System Interaction (HSI)}, publisher = {IEEE}, isbn = {978-1-6654-6823-7 (Print)}, issn = {2158-2246 (Print)}, doi = {10.1109/HSI55341.2022.9869467}, pages = {8 Seiten}, year = {2022}, abstract = {Digital shadows play a central role for the next generation industrial internet, also known as Internet of Production (IoP). However, prior research has not considered systematically how human actors interact with digital shadows, shaping their potential for success. To address this research gap, we assembled an interdisciplinary team of authors from diverse areas of human-centered research to propose and discuss design and research recommendations for the implementation of industrial user interfaces for digital shadows, as they are currently conceptualized for the IoP. Based on the four use cases of decision support systems, knowledge sharing in global production networks, human-robot collaboration, and monitoring employee workload, we derive recommendations for interface design and enhancing workers' capabilities. This analysis is extended by introducing requirements from the higher-level perspectives of governance and organization.}, language = {en} } @inproceedings{RajanButenwegDalgueretal.2017, author = {Rajan, S. and Butenweg, Christoph and Dalguer, L. A. and An, J. H. and Renault, P. and Klinkel, S.}, title = {Fragility curves for a three-storey reinforced concrete test structure of the international benchmark SMART 2013}, series = {16th World Conference on Earthquake, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017}, booktitle = {16th World Conference on Earthquake, 16WCEE 2017 Santiago Chile, January 9th to 13th 2017}, publisher = {Chilean Association on Seismology and Earthquake Engineering (ACHISINA)}, year = {2017}, language = {en} } @inproceedings{RajanHoltschoppenDalgueretal.2016, author = {Rajan, Sreelakshmy and Holtschoppen, B. and Dalguer, L. A. and Klinkel, S. and Butenweg, Christoph}, title = {Seismic fragility analysis of a non-conventional reinforced concrete structure considering different uncertainties}, series = {Proceedings of ISMA2016, International Conference on Noise and Vibration Engineering/USD2016, International Conference on Uncertainty in Structural Dynamics, / ISMA 2016, USD 2016}, booktitle = {Proceedings of ISMA2016, International Conference on Noise and Vibration Engineering/USD2016, International Conference on Uncertainty in Structural Dynamics, / ISMA 2016, USD 2016}, editor = {Sas, P.}, publisher = {KU Leuven}, address = {Leuven}, pages = {4213 -- 4225}, year = {2016}, language = {en} } @inproceedings{RajanKubalskiAltayetal.2017, author = {Rajan, Sreelakshmy and Kubalski, Thomas and Altay, Okyay and Dalguer, Luis A and Butenweg, Christoph}, title = {Multi-dimensional fragility analysis of a RC building with components using response surface method}, series = {24th International Conference on Structural Mechanics in Reactor Technology, Busan, Korea, 20-25 August, 2017}, booktitle = {24th International Conference on Structural Mechanics in Reactor Technology, Busan, Korea, 20-25 August, 2017}, publisher = {International Assn for Structural Mechanics in Reactor Technology (IASMiRT)}, address = {Raleigh, USA}, isbn = {9781510856776}, pages = {3126 -- 3135}, year = {2017}, abstract = {Conventional fragility curves describe the vulnerability of the main structure under external hazards. However, in complex structures such as nuclear power plants, the safety or the risk depends also on the components associated with a system. The classical fault tree analysis gives an overall view of the failure and contains several subsystems to the main event, however, the interactions in the subsystems are not well represented. In order to represent the interaction of the components, a method suggested by Cimellaro et al. (2006) using multidimensional performance limit state functions to obtain the system fragility curves is adopted. This approach gives the possibility of deriving the cumulative fragility taking into account the interaction of the response of different components. In this paper, this approach is used to evaluate seismic risk of a representative electrical building infrastructure, including the component, of a nuclear power plant. A simplified model of the structure, with nonlinear material behavior is employed for the analysis in Abaqus©. The input variables considered are the material parameters, boundary conditions and the seismic input. The variability of the seismic input is obtained from selected ground motion time histories of spectrum compatible synthetic ccelerograms. Unlike the usual Monte Carlo methods used for the probabilistic analysis of the structure, a computationally effective response surface method is used. This method reduces the computational effort of the calculations by reducing the required number of samples.}, language = {en} } @article{RateikeSiebourgSchmidetal.1990, author = {Rateike, Franz-Matthias and Siebourg, W. and Schmid, H. and Anders, S.}, title = {Birefringence - An important property of plastic substrates for magneto-optical storage disks / W. Siebourg ; H. Schmid ; F. M. Rateike ; S. Anders ; U. Grigo ; H. L{\"o}wer}, series = {Polymer engineering \& science / Society of Plastics Engineers. 30 (1990), H. 18}, journal = {Polymer engineering \& science / Society of Plastics Engineers. 30 (1990), H. 18}, isbn = {0032-3888}, pages = {1133 -- 1139}, year = {1990}, language = {en} } @article{RateikeWeyerWiedenmannetal.1981, author = {Rateike, Franz-Matthias and Weyer, K. G. and Wiedenmann, H. and MacGillivray, W. R.}, title = {Observation of absorptive optical bistability in a fabry-perot cavity containing multiple atomic beams / K. G. Weyer ; H. Wiedenmann ; M. Rateike ; W. R. Mac Gillivray ; P. Meystre ; H. Walther}, series = {Optics communications. 37 (1981), H. 6}, journal = {Optics communications. 37 (1981), H. 6}, isbn = {0030-4018}, pages = {426 -- 430}, year = {1981}, language = {en} } @article{RathMottaghy2007, author = {Rath, V. and Mottaghy, Darius}, title = {Smooth inversion for ground surface temperature histories: estimating the optimum regularization parameter by generalized cross-validation}, series = {Geophysical Journal International}, volume = {171}, journal = {Geophysical Journal International}, number = {3}, issn = {1365-246X}, doi = {10.1111/j.1365-246X.2007.03587.x}, pages = {1440 -- 1448}, year = {2007}, language = {en} } @inproceedings{ReindlButenwegKubalski2011, author = {Reindl, Lukas and Butenweg, Christoph and Kubalski, Thomas}, title = {Numerical simulation of unreinforced masonry walls subject to dynamic out-of-plane loading}, series = {COMPDYN 2011 : ECCOMAS Thematic Conference ; Proceedings of the 3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering ; 25-28 May, 2011, Corfu, Greece / Eds.: M. Papadrakakis ...}, booktitle = {COMPDYN 2011 : ECCOMAS Thematic Conference ; Proceedings of the 3rd International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering ; 25-28 May, 2011, Corfu, Greece / Eds.: M. Papadrakakis ...}, publisher = {National Technical Univ. of Athens}, address = {Athen}, organization = {COMPDYN <2011, Corfu>}, isbn = {978-960-99994-0-3}, pages = {1 -- 10}, year = {2011}, language = {en} } @inproceedings{ReindlParkNordaetal.2010, author = {Reindl, Lukas and Park, Jin and Norda, Hannah and Butenweg, Christoph}, title = {Seismic design of masonry walls subject to out-of-plane bending}, series = {Proceedings of the Tenth International Conference on Computational Structures Technology : Valencia, Spain, 14 - 17 September 2010 / organised in association with: Universidad Politecnica de Valencia ... Ed. by B. H. V. Topping ...}, booktitle = {Proceedings of the Tenth International Conference on Computational Structures Technology : Valencia, Spain, 14 - 17 September 2010 / organised in association with: Universidad Politecnica de Valencia ... Ed. by B. H. V. Topping ...}, publisher = {Civil-Comp Press}, address = {Kippen}, organization = {International Conference on Computational Structures Technology <10, 2010, Valencia>}, isbn = {978-1-905088-36-2}, doi = {10.4203/ccp.93.348}, pages = {Paper 348}, year = {2010}, language = {en} } @inproceedings{RenaultButenweg2005, author = {Renault, Philippe and Butenweg, Christoph}, title = {Seismic vulnerability assessment of bridges}, series = {First Munich Bridge Assessment Conference, MBAC 2005 : Munich, 20.-25. June 2005}, booktitle = {First Munich Bridge Assessment Conference, MBAC 2005 : Munich, 20.-25. June 2005}, organization = {Munich Bridge Assessment Conference <1, 2005>}, pages = {1 -- 16}, year = {2005}, language = {en} } @inproceedings{RenaultButenwegMistler2005, author = {Renault, Philippe and Butenweg, Christoph and Mistler, Michael}, title = {Seismic vulnerability assessment system for bridges}, series = {Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing : [Rome, Italy, 30. August - 2. September 2005] / ed. by B. H. V. Topping}, booktitle = {Proceedings of the Tenth International Conference on Civil, Structural and Environmental Engineering Computing : [Rome, Italy, 30. August - 2. September 2005] / ed. by B. H. V. Topping}, publisher = {Civil-Comp Press}, address = {Stirling}, organization = {International Conference on Civil, Structural and Environmental Engineering Computing <10, 2005, Rome>}, isbn = {1-905088-00-0}, pages = {1 -- 14}, year = {2005}, language = {en} } @inproceedings{RendonSchwagerGhiasietal.2020, author = {Rendon, Carlos and Schwager, Christian and Ghiasi, Mona and Schmitz, Pascal and Bohang, Fakhri and Chico Caminos, Ricardo Alexander and Teixeira Boura, Cristiano Jos{\´e} and Herrmann, Ulf}, title = {Modeling and upscaling of a pilot bayonettube reactor for indirect solar mixed methane reforming}, series = {AIP Conference Proceedings}, booktitle = {AIP Conference Proceedings}, number = {2303}, doi = {10.1063/5.0029974}, pages = {170012-1 -- 170012-9}, year = {2020}, abstract = {A 16.77 kW thermal power bayonet-tube reactor for the mixed reforming of methane using solar energy has been designed and modeled. A test bench for the experimental tests has been installed at the Synlight facility in Juelich, Germany and has just been commissioned. This paper presents the solar-heated reactor design for a combined steam and dry reforming as well as a scaled-up process simulation of a solar reforming plant for methanol production. Solar power towers are capable of providing large amounts of heat to drive high-endothermic reactions, and their integration with thermochemical processes shows a promising future. In the designed bayonet-tube reactor, the conventional burner arrangement for the combustion of natural gas has been substituted by a continuous 930 °C hot air stream, provided by means of a solar heated air receiver, a ceramic thermal storage and an auxiliary firing system. Inside the solar-heated reactor, the heat is transferred by means of convective mechanism mainly; instead of radiation mechanism as typically prevailing in fossil-based industrial reforming processes. A scaled-up solar reforming plant of 50.5 MWth was designed and simulated in Dymola® and AspenPlus®. In comparison to a fossil-based industrial reforming process of the same thermal capacity, a solar reforming plant with thermal storage promises a reduction up to 57 \% of annual natural gas consumption in regions with annual DNI-value of 2349 kWh/m2. The benchmark solar reforming plant contributes to a CO2 avoidance of approx. 79 kilotons per year. This facility can produce a nominal output of 734.4 t of synthesis gas and out of this 530 t of methanol a day.}, language = {en} } @inproceedings{RensFerreinPoel2008, author = {Rens, Gavin and Ferrein, Alexander and Poel, Etienne van der}, title = {Extending DTGolog to deal with POMD-Ps}, series = {Proceedings of the Nineteenth Annual Symposium of the Pattern Recognition Association of South Africa (PRASA 2008)}, booktitle = {Proceedings of the Nineteenth Annual Symposium of the Pattern Recognition Association of South Africa (PRASA 2008)}, organization = {Pattern Recognition Association of South Africa}, pages = {49 -- 54}, year = {2008}, language = {en} } @misc{ReyesOchoa2014, type = {Master Thesis}, author = {Reyes Ochoa, Leonel}, title = {Engineering aspects of a parabolic trough collector field with direct steam generation and an organic rankine cycle}, publisher = {Fachhochschule Aachen}, address = {Aachen}, pages = {X, 72 S.}, year = {2014}, 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} }