@article{RosenauerOberstLitvinovetal.2000, author = {Rosenauer, A. and Oberst, W. and Litvinov, D. and Gerthsen, D. and F{\"o}rster, Arnold and Schmidt, R.}, title = {Structural and Chemical Investigation of In-0.6Ga0.4As Stranski-Krastanow Layers Burried in GaAs by Transmission Electron Microscopy}, series = {Physical Review B. 61 (2000), H. 12}, journal = {Physical Review B. 61 (2000), H. 12}, isbn = {1095-3795}, pages = {8276 -- 8288}, year = {2000}, language = {en} } @article{RochefortVerverGrunendahletal.2005, author = {Rochefort, E. de and Verver, M. and Grunendahl, A. and Mooi, H. and Butenweg, Christoph}, title = {Detailed modelling of the lumbar spine for investigations of low back pain}, series = {SAE transactions : papers presented at Society and Section meetings / Society of Automotive Engineers}, volume = {Volume 114}, journal = {SAE transactions : papers presented at Society and Section meetings / Society of Automotive Engineers}, number = {Part 7}, organization = {Society of Automotive Engineers}, issn = {0096-736X}, pages = {788 -- 796}, year = {2005}, 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{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} } @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{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{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} } @article{PieperIvanyshyn2008, author = {Pieper, Martin and Ivanyshyn, Olha}, title = {Nonlinear integral equations for a 3D inverse acoustic scattering problem : abstract / O. Ivanyshyn and M. Pieper}, year = {2008}, language = {en} } @article{Pieper2009, author = {Pieper, Martin}, title = {Vector hyperinterpolation on the sphere}, series = {Journal of approximation theory. 156 (2009), H. 2}, journal = {Journal of approximation theory. 156 (2009), H. 2}, isbn = {0021-9045}, pages = {173 -- 186}, year = {2009}, language = {en} } @article{Pieper2008, author = {Pieper, Martin}, title = {Nonlinear integral equations for an inverse electromagnetic scattering problem}, series = {Journal of Physics Conference Series. 124 (2008)}, journal = {Journal of Physics Conference Series. 124 (2008)}, isbn = {1742-6596}, year = {2008}, 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{NobisSchmittSchemmetal.2020, author = {Nobis, Moritz and Schmitt, Carlo and Schemm, Ralf and Schnettler, Armin}, title = {Pan-European CVAR-constrained stochastic unit commitment in day-ahead and intraday electricity markets}, series = {Energies}, volume = {13}, journal = {Energies}, number = {Art. 2339}, publisher = {MDPI}, address = {Basel}, issn = {1996-1073}, doi = {10.3390/en13092339}, pages = {1 -- 35}, year = {2020}, abstract = {The fundamental modeling of energy systems through individual unit commitment decisions is crucial for energy system planning. However, current large-scale models are not capable of including uncertainties or even risk-averse behavior arising from forecasting errors of variable renewable energies. However, risks associated with uncertain forecasting errors have become increasingly relevant within the process of decarbonization. The intraday market serves to compensate for these forecasting errors. Thus, the uncertainty of forecasting errors results in uncertain intraday prices and quantities. Therefore, this paper proposes a two-stage risk-constrained stochastic optimization approach to fundamentally model unit commitment decisions facing an uncertain intraday market. By the nesting of Lagrangian relaxation and an extended Benders decomposition, this model can be applied to large-scale, e.g., pan-European, power systems. The approach is applied to scenarios for 2023—considering a full nuclear phase-out in Germany—and 2035—considering a full coal phase-out in Germany. First, the influence of the risk factors is evaluated. Furthermore, an evaluation of the market prices shows an increase in price levels as well as an increasing day-ahead-intraday spread in 2023 and in 2035. Finally, it is shown that intraday cross-border trading has a significant influence on trading volumes and prices and ensures a more efficient allocation of resources.}, language = {en} } @article{MykoniouButenwegHoltschoppenetal.2016, author = {Mykoniou, Konstantin and Butenweg, Christoph and Holtschoppen, Britta and Klinkel, Sven}, title = {Seismic response analysis of adjacent liquid-storage tanks}, series = {Earthquake engineering and structural dynamics}, volume = {45}, journal = {Earthquake engineering and structural dynamics}, number = {11}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1096-9845 (E-Journal); 0098-8847 (Print)}, doi = {10.1002/eqe.2726}, pages = {1779 -- 1796}, year = {2016}, abstract = {A refined substructure technique in the frequency domain is developed, which permits consideration of the interaction effects among adjacent containers through the supporting deformable soil medium. The tank-liquid systems are represented by means of mechanical models, whereas discrete springs and dashpots stand for the soil beneath the foundations. The proposed model is employed to assess the responses of adjacent circular, cylindrical tanks for harmonic and seismic excitations over wide range of tank proportions and soil conditions. The influence of the number, spatial arrangement of the containers and their distance on the overall system's behavior is addressed. The results indicate that the cross-interaction effects can substantially alter the impulsive components of response of each individual element in a tank farm. The degree of this impact is primarily controlled by the tank proportions and the proximity of the predominant natural frequencies of the shell-liquid-soil systems and the input seismic motion. The group effects should be not a priori disregarded, unless the tanks are founded on shallow soil deposit overlying very stiff material or bedrock.}, language = {en} } @article{MottaghyVosteenSchellschmidt2008, author = {Mottaghy, Darius and Vosteen, Hans-Dieter and Schellschmidt, R{\"u}diger}, title = {Temperature dependence of the relationship of thermal diffusivity versus thermal conductivity for crystalline rocks}, series = {International Journal of Earth Sciences}, volume = {97}, journal = {International Journal of Earth Sciences}, number = {2}, issn = {1437-3262}, doi = {10.1007/s00531-007-0238-3}, pages = {435 -- 442}, year = {2008}, language = {en} } @article{MottaghySchwambornRath2013, author = {Mottaghy, Darius and Schwamborn, G. and Rath, V.}, title = {Past climate changes and permafrost depth at the Lake El'gygytgyn site: implications from data and thermal modeling}, series = {Climate of the Past}, volume = {9}, journal = {Climate of the Past}, number = {1}, publisher = {Copernicus}, address = {Katlenburg-Lindau}, issn = {1814-9332}, doi = {10.5194/cp-9-119-2013}, pages = {119 -- 133}, year = {2013}, language = {en} } @article{MottaghySchellschmidtPopovetal.2005, author = {Mottaghy, Darius and Schellschmidt, R. and Popov, Y. A. and Clauser, C. and Kukkonen, I. T. and Nover, G. and Milanovsky, S. and Romushkevich, R. A.}, title = {New heat flow data from the immediate vicinity of the Kola super-deep borehole: Vertical variation in heat flow density confirmed and attributed to advection}, series = {Tectonophysics}, volume = {401}, journal = {Tectonophysics}, number = {1-2}, issn = {1879-3266}, doi = {10.1016/j.tecto.2005.03.005}, pages = {119 -- 142}, year = {2005}, language = {en} } @article{MottaghyRath2006, author = {Mottaghy, Darius and Rath, Volker}, title = {Latent heat effects in subsurface heat transport modelling and their impact on palaeotemperature reconstructions}, series = {Geophysical Journal International}, volume = {164}, journal = {Geophysical Journal International}, number = {1}, issn = {1365-246X}, doi = {10.1111/j.1365-246X.2005.02843.x}, pages = {236 -- 245}, year = {2006}, language = {en} } @article{MottaghyPechnigVogt2011, author = {Mottaghy, Darius and Pechnig, Renate and Vogt, Christian}, title = {The geothermal project Den Haag: 3D numerical models for temperature prediction and reservoir simulation}, series = {Geothermics}, volume = {40}, journal = {Geothermics}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0375-6505}, doi = {10.1016/j.geothermics.2011.07.001}, pages = {199 -- 210}, year = {2011}, abstract = {The proposed Den Haag Zuidwest district heating system of the city of The Hague consists of a deep doublet in a Jurassic sandstone layer that is designed for a production temperature of 75 °C and a reinjection temperature of 40 °C at a flow rate of 150 m3 h-1. The prediction of reservoir temperature and production behavior is crucial for success of the proposed geothermal doublet. This work presents the results of a study of the important geothermal and geohydrological issues for the doublet design. In the first phase of the study, the influences of the three-dimensional (3D) structures of anticlines and synclines on the temperature field were examined. A comprehensive petrophysical investigation was performed to build a large scale 3D-model of the reservoir. Several bottomhole temperatures (BHTs), as well as petrophysical logs were used to calibrate the model using thermal conductivity measurements on 50 samples from boreholes in different lithological units in the study area. Profiles and cross sections extracted from the calculated temperature field were used to study the temperature in the surrounding areas of the planned doublet. In the second phase of the project, a detailed 3D numerical reservoir model was set up, with the aim of predicting the evolution of the producer and injector temperatures, and the extent of the cooled area around the injector. The temperature model from the first phase provided the boundary conditions for the reservoir model. Hydraulic parameters for the target horizons, such as porosity and permeability, were taken from data available from the nearby exploration wells. The simulation results are encouraging as no significant thermal breakthrough is predicted. For the originally planned location of the producer, the extracted water temperature is predicted to be around 79 °C, with an almost negligible cooling in the first 50 years of production. When the producer is located shallower parts of the reservoir, the yield water temperatures is lower, starting at ≈76 °C and decreasing to ≈74 °C after 50 years of operation. This comparatively larger decrease in temperature with time is caused by the structural feature of the reservoir, namely a higher dip causes the cooler water to easily move downward. In view of the poor reservoir data, the reservoir simulation model is constructed to allow iterative updates using data assimilation during planned drilling, testing, and production phases. Measurements during an 8 h pumping test carried out in late 2010 suggest that a flow rate of 150 m3 h-1 is achievable. Fluid temperatures of 76.5 °C were measured, which is very close to the predicted value.}, language = {en} }