@article{JildehWagnerSchoeningetal.2015, author = {Jildeh, Zaid B. and Wagner, Torsten and Sch{\"o}ning, Michael Josef and Pieper, Martin}, title = {Simulating the electromagnetic-thermal treatment of thin aluminium layers for adhesion improvement}, series = {Physica status solidi (a)}, volume = {Vol. 212}, journal = {Physica status solidi (a)}, number = {6}, publisher = {Wiley}, address = {Weinheim}, issn = {1862-6319}, doi = {10.1002/pssa.201431893}, pages = {1234 -- 1241}, year = {2015}, abstract = {A composite layer material used in packaging industry is made from joining layers of different materials using an adhesive. An important processing step in the production of aluminium-containing composites is the surface treatment and consequent coating of adhesive material on the aluminium surface. To increase adhesion strength between aluminium layer and the adhesive material, the foil is heat treated. For efficient heating, induction heating was considered as state-of-the-art treatment process. Due to the complexity of the heating process and the unpredictable nature of the heating source, the control of the process is not yet optimised. In this work, a finite element analysis of the process was established and various process parameters were studied. The process was simplified and modelled in 3D. The numerical model contains an air domain, an aluminium layer and a copper coil fitted with a magnetic field concentrating material. The effect of changing the speed of the aluminium foil (or rolling speed) was studied with the change of the coil current. Statistical analysis was used for generating a general control equation of coil current with changing rolling speed.}, language = {en} } @article{ChenClauserMarquartetal.2015, author = {Chen, Tao and Clauser, Christoph and Marquart, Gabriele and Willbrand, Karen and Mottaghy, Darius}, title = {A new upscaling method for fractured porous media}, series = {Advances in Water Resources}, volume = {80}, journal = {Advances in Water Resources}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0309-1708}, doi = {10.1016/j.advwatres.2015.03.009}, pages = {60 -- 68}, year = {2015}, language = {en} } @article{KuertenMottaghyZiegler2015, author = {K{\"u}rten, Sylvia and Mottaghy, Darius and Ziegler, Martin}, title = {A new model for the description of the heat transfer for plane thermo-active geotechnical systems based on thermal resistances}, series = {Acta Geotechnica}, volume = {10}, journal = {Acta Geotechnica}, number = {2}, publisher = {Springer}, address = {Berlin}, issn = {1861-1133}, doi = {10.1007/s11440-014-0311-6}, pages = {219 -- 229}, year = {2015}, language = {en} } @article{KuertenMottaghyZiegler2015, author = {K{\"u}rten, Sylvia and Mottaghy, Darius and Ziegler, Martin}, title = {Design of plane energy geostructures based on laboratory tests and numerical modelling}, series = {Energy and Buildings}, volume = {107}, journal = {Energy and Buildings}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0378-7788}, doi = {10.1016/j.enbuild.2015.08.039}, pages = {434 -- 444}, year = {2015}, language = {en} } @article{TaddeiButenwegKlinkel2015, author = {Taddei, Francesca and Butenweg, Christoph and Klinkel, S.}, title = {Parametric investigation of the soil-structure interaction effects on the dynamic behaviour of a shallow foundation supported wind turbine considering a layered soil}, series = {Wind energy : an international journal for progress and applications in wind power conversion technology}, volume = {Volume 18}, journal = {Wind energy : an international journal for progress and applications in wind power conversion technology}, number = {Issue 3}, publisher = {Wiley}, address = {Weinheim}, issn = {1099-1824 (E-Journal); 1095-4244 (Print)}, doi = {10.1002/we.1703}, pages = {399 -- 417}, year = {2015}, language = {en} } @article{AlebouyehSamamiPieperBreitbachetal.2014, author = {Alebouyeh Samami, Behzad and Pieper, Martin and Breitbach, Gerd and Hodapp, Josef}, title = {Heat production in the windings of the stators of electric machines under stationary condition}, series = {Heat and mass transfer}, volume = {50}, journal = {Heat and mass transfer}, publisher = {Springer}, address = {Heidelberg}, issn = {0947-7411 (Print) ; 1432-1181 (E-Journal)}, doi = {10.1007/s00231-014-1371-8}, pages = {1707 -- 1716}, year = {2014}, abstract = {In electric machines due to high currents and resistive losses (joule heating) heat is produced. To avoid damages by overheating the design of effective cooling systems is required. Therefore the knowledge of heat sources and heat transfer processes is necessary. The purpose of this paper is to illustrate a good and effective calculation method for the temperature analysis based on homogenization techniques. These methods have been applied for the stator windings in a slot of an electric machine consisting of copper wires and resin. The key quantity here is an effective thermal conductivity, which characterizes the heterogeneous wire resin-arrangement inside the stator slot. To illustrate the applicability of the method, the analysis of a simplified, homogenized model is compared with the detailed analysis of temperature behavior inside a slot of an electric machine according to the heat generation. We considered here only the stationary situation. The achieved numerical results are accurate and show that the applied homogenization technique works in practice. Finally the results of simulations for the two cases, the original model of the slot and the homogenized model chosen for the slot (unit cell), are compared to experimental results.}, language = {en} } @article{VogtMottaghyRathetal.2014, author = {Vogt, C. and Mottaghy, Darius and Rath, V. and Marquart, G. and Dijkshoorn, L. and Wolf, A. and Clauser, C.}, title = {Vertical variation in heat flow on the Kola Peninsula: palaeoclimate or fluid flow?}, series = {Geophysical Journal International}, volume = {199}, journal = {Geophysical Journal International}, number = {2}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1365-246X}, doi = {10.1093/gji/ggu282}, pages = {829 -- 843}, year = {2014}, abstract = {Following earlier studies, we present forward and inverse simulations of heat and fluid transport of the upper crust using a local 3-D model of the Kola area. We provide best estimates for palaeotemperatures and permeabilities, their errors and their dependencies. Our results allow discriminating between the two mentioned processes to a certain extent, partly resolving the non-uniqueness of the problem. We find clear indications for a significant contribution of advective heat transport, which, in turn, imply only slightly lower ground surface temperatures during the last glacial maximum relative to the present value. These findings are consistent with the general background knowledge of (i) the fracture zones and the corresponding fluid movements in the bedrock and (ii) the glacial history of the Kola area.}, language = {en} } @article{SrivastavaLahiriMaitietal.2014, author = {Srivastava, A. and Lahiri, S. and Maiti, M. and Knolle, F. and Hoyler, Friedrich and Scherer, Ulrich W. and Schnug, E. W.}, title = {Study of naturally occurring radioactive material (NORM) in top soil of Punjab State from the North Western part of India}, series = {Journal of Radioanalytical and Nuclear Chemistry}, volume = {2014}, journal = {Journal of Radioanalytical and Nuclear Chemistry}, number = {302}, publisher = {Springer Nature}, address = {Basel}, issn = {1588-2780 (E-Journal); 0022-4081 (Print); 0134-0719 (Print); 0236-5731 (Print); 1417-2097 (Print)}, doi = {0.1007/s10967-014-3450-1}, pages = {1049 -- 1052}, year = {2014}, language = {en} } @article{SabitovaEbertLenzetal.2013, author = {Sabitova, A. and Ebert, Ph. and Lenz, A. and Schaafhausen, S. and Ivanova, L. and D{\"a}hne, M. and Hoffmann, A. and Dunin-Borkowski, R. E. and F{\"o}rster, Arnold and Grandidier, B. and Eisele, H.}, title = {Intrinsic bandgap of cleaved ZnO(112¯0) surfaces}, series = {Applied physics letters}, volume = {Vol. 102}, journal = {Applied physics letters}, issn = {1077-3118 (E-Journal); 0003-6951 (Print)}, pages = {021608}, year = {2013}, 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{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{MarxSchenkBehrensetal.2013, author = {Marx, Ulrich and Schenk, Friedrich and Behrens, Jan and Meyr, Ulrike and Wanek, Paul and Zang, Werner and Schmitt, Robert and Br{\"u}stle, Oliver and Zenke, Martin and Klocke, Fritz}, title = {Automatic production of induced pluripotent stem cells}, series = {Procedia CIRP : First CIRP Conference on BioManufacturing}, volume = {Vol. 5}, journal = {Procedia CIRP : First CIRP Conference on BioManufacturing}, publisher = {Elsevier}, address = {Amsterdam}, issn = {2212-8271}, pages = {2 -- 6}, year = {2013}, language = {en} } @article{EdipGarevskiButenwegetal.2013, author = {Edip, Kemal and Garevski, Mihail and Butenweg, Christoph and Sesov, Vlatko and Cvetanovska, Julijana and Gjorgiev, Igor}, title = {Numerical simulation of geotechnical problems by coupled finite and infinite elements}, series = {Journal of civil engineering and architecture}, volume = {7}, journal = {Journal of civil engineering and architecture}, number = {1}, publisher = {David Publishing}, address = {Libertyville}, issn = {1934-7359 (E-Journal)}, pages = {68 -- 77}, year = {2013}, language = {en} } @article{FleischhakerKraussSchaettigeretal.2013, author = {Fleischhaker, Robert and Krauß, Nico and Sch{\"a}ttiger, Farina and Dekorsy, Thomas}, title = {Consistent characterization of semiconductor saturable absorber mirrors with singe-pulse and pump-probe spectroscopy}, series = {Optics Express}, volume = {21}, journal = {Optics Express}, number = {6}, publisher = {Optica}, address = {Washington, DC}, issn = {1094-4087}, doi = {10.1364/OE.21.006764}, pages = {6764 -- 6776}, year = {2013}, 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{WernerKrumbeSchumacheretal.2011, author = {Werner, Frederik and Krumbe, Christoph and Schumacher, Katharina and Groebel, Simone and Spelthahn, Heiko and Stellberg, Michael and Wagner, Torsten and Yoshinobu, Tatsuo and Selmer, Thorsten and Keusgen, Michael and Baumann, Marcus and Sch{\"o}ning, Michael Josef}, title = {Determination of the extracellular acidification of Escherichia coli by a light-addressable potentiometric sensor}, series = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, journal = {Physica status solidi (a) : applications and material science. 208 (2011), H. 6}, publisher = {Wiley}, address = {Weinheim}, isbn = {1862-6319}, pages = {1340 -- 1344}, year = {2011}, language = {en} } @article{KernSchelthoffMathieu2011, author = {Kern, Alexander and Schelthoff, Christof and Mathieu, Moritz}, title = {Probability of lightning strikes to air-terminations of structures using the electro-geometrical model theory and the statistics of lightning current parameters}, series = {Atmospheric Research. 104 (2011)}, journal = {Atmospheric Research. 104 (2011)}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0169-8095}, year = {2011}, 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{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{KernSchelthoffMathieu2011, author = {Kern, Alexander and Schelthoff, Christof and Mathieu, Moritz}, title = {Calculation of interception efficiencies for airterminations using a dynamic electro-geometrical model}, publisher = {IEEE}, address = {New York}, pages = {1 -- 6}, year = {2011}, language = {en} } @article{LandersKern2011, author = {Landers, Ernst Ulrich and Kern, Alexander}, title = {Future evolution of risk management for structures : Advancement for the future IEC 62305-2 Ed3}, publisher = {IEEE}, address = {New York}, pages = {1 -- 6}, year = {2011}, 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} } @article{FleischhakerEvers2011, author = {Fleischhaker, Robert and Evers, J{\"o}rg}, title = {A Maxwell-Schr{\"o}dinger solver for quantum optical few-level systems}, series = {Computer Physics Communications}, volume = {182}, journal = {Computer Physics Communications}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0010-4655}, doi = {10.1016/j.cpc.2010.10.018}, pages = {739 -- 747}, year = {2011}, abstract = {The msprop program presented in this work is capable of solving the Maxwell-Schr{\"o}dinger equations for one or several laser fields propagating through a medium of quantum optical few-level systems in one spatial dimension and in time. In particular, it allows to numerically treat systems in which a laser field interacts with the medium with both its electric and magnetic component at the same time. The internal dynamics of the few-level system is modeled by a quantum optical master equation which includes coherent processes due to optical transitions driven by the laser fields as well as incoherent processes due to decay and dephasing. The propagation dynamics of the laser fields is treated in slowly varying envelope approximation resulting in a first order wave equation for each laser field envelope function. The program employs an Adams predictor formula second order in time to integrate the quantum optical master equation and a Lax-Wendroff scheme second order in space and time to evolve the wave equations for the fields. The source function in the Lax-Wendroff scheme is specifically adapted to allow taking into account the simultaneous coupling of a laser field to the polarization and the magnetization of the medium. To reduce execution time, a customized data structure is implemented and explained. In three examples the features of the program are demonstrated and the treatment of a system with a phase-dependent cross coupling of the electric and magnetic field component of a laser field is shown.}, language = {en} } @article{AlexopoulosHoffschmidt2010, author = {Alexopoulos, Spiros and Hoffschmidt, Bernhard}, title = {Solar tower power plant in Germany and future perspectives of the development of the technology in Greece and Cyprus}, series = {Renewable Energy . 35 (2010), H. 7}, journal = {Renewable Energy . 35 (2010), H. 7}, isbn = {0960-1481}, pages = {1352 -- 1356}, year = {2010}, language = {en} } @article{GeimerSauerbornHoffschmidtetal.2010, author = {Geimer, Konstantin and Sauerborn, Markus and Hoffschmidt, Bernhard and Schmitz, Mark and G{\"o}ttsche, Joachim}, title = {Test Facility for Absorber Specimens of Solar Tower Power Plants}, series = {Advances in Science and Technology. 74 (2010)}, journal = {Advances in Science and Technology. 74 (2010)}, pages = {266 -- 271}, year = {2010}, 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{KernSchelthoffMathieu2010, author = {Kern, Alexander and Schelthoff, Christof and Mathieu, Moritz}, title = {Probability of lightning strikes to air-terminations of structures using the electro-geometrical model theory and the statistics of lightning current parameters}, pages = {750-1 -- 750-8}, year = {2010}, language = {en} } @article{BouquegneauKernRousseau2010, author = {Bouquegneau, Christian and Kern, Alexander and Rousseau, Alain}, title = {Lightning safety guidelines}, pages = {1 -- 6}, year = {2010}, language = {en} } @article{KernFrentzelBehrens2010, author = {Kern, Alexander and Frentzel, Ralf and Behrens, J{\"o}rg}, title = {Simulation of the transient voltages in the auxiliary power network of a large power plant in case of a direct lightning strike to the high-voltage overhead transmission line}, pages = {749-1 -- 749-7}, year = {2010}, language = {en} } @article{KernKloetersPferdemenges2010, author = {Kern, Alexander and Kl{\"o}ters, Georg and Pferdemenges, J{\"o}rg}, title = {Optimised protection against lightning for the signalling and safety systems of level crossings on non-electrified railway lines}, series = {RTR : European Rail Technology Review}, volume = {50}, journal = {RTR : European Rail Technology Review}, number = {2}, isbn = {0079-9548}, year = {2010}, language = {en} } @article{VogtMottaghyWolfetal.2010, author = {Vogt, C. and Mottaghy, Darius and Wolf, A. and Rath, V. and Pechnig, R. and Clauser, C.}, title = {Reducing temperature uncertainties by stochastic geothermal reservoir modelling}, series = {Geophysical Journal International}, volume = {181}, journal = {Geophysical Journal International}, number = {1}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1365-246X}, doi = {10.1111/j.1365-246X.2009.04498.x}, pages = {321 -- 333}, year = {2010}, abstract = {Quantifying and minimizing uncertainty is vital for simulating technically and economically successful geothermal reservoirs. To this end, we apply a stochastic modelling sequence, a Monte Carlo study, based on (i) creating an ensemble of possible realizations of a reservoir model, (ii) forward simulation of fluid flow and heat transport, and (iii) constraining post-processing using observed state variables. To generate the ensemble, we use the stochastic algorithm of Sequential Gaussian Simulation and test its potential fitting rock properties, such as thermal conductivity and permeability, of a synthetic reference model and—performing a corresponding forward simulation—state variables such as temperature. The ensemble yields probability distributions of rock properties and state variables at any location inside the reservoir. In addition, we perform a constraining post-processing in order to minimize the uncertainty of the obtained distributions by conditioning the ensemble to observed state variables, in this case temperature. This constraining post-processing works particularly well on systems dominated by fluid flow. The stochastic modelling sequence is applied to a large, steady-state 3-D heat flow model of a reservoir in The Hague, Netherlands. The spatial thermal conductivity distribution is simulated stochastically based on available logging data. Errors of bottom-hole temperatures provide thresholds for the constraining technique performed afterwards. This reduce the temperature uncertainty for the proposed target location significantly from 25 to 12 K (full distribution width) in a depth of 2300 m. Assuming a Gaussian shape of the temperature distribution, the standard deviation is 1.8 K. To allow a more comprehensive approach to quantify uncertainty, we also implement the stochastic simulation of boundary conditions and demonstrate this for the basal specific heat flow in the reservoir of The Hague. As expected, this results in a larger distribution width and hence, a larger, but more realistic uncertainty estimate. However, applying the constraining post-processing the uncertainty is again reduced to the level of the post-processing without stochastic boundary simulation. Thus, constraining post-processing is a suitable tool for reducing uncertainty estimates by observed state variables.}, language = {en} } @article{FleischhakerEversDey2010, author = {Fleischhaker, Robert and Evers, J{\"o}rg and Dey, Tarak N.}, title = {Phase modulation induced by cooperative effects in electromagnetically induced transparency}, series = {Physical Review A - Atomic, molecular, and optical physics}, volume = {82}, journal = {Physical Review A - Atomic, molecular, and optical physics}, number = {1}, publisher = {AIP Publishing}, address = {Melville, NY}, issn = {1050-2947}, doi = {10.1103/PhysRevA.82.013815}, pages = {013815}, year = {2010}, abstract = {We analyze the influence of dipole-dipole interactions in an electromagnetically induced transparency set up for a density at the onset of cooperative effects. To this end, we include mean-field models for the influence of local-field corrections and radiation trapping into our calculation. We show both analytically and numerically that the polarization contribution to the local field strongly modulates the phase of a weak pulse. We give an intuitive explanation for this local-field-induced phase modulation and demonstrate that it distinctively differs from the nonlinear self-phase-modulation that a strong pulse experiences in a Kerr medium.}, language = {en} } @article{BeckerFrauenrathHezeletal.2010, author = {Becker, Meike and Frauenrath, Tobias and Hezel, Fabian and Krombach, Gabriele A. and Kremer, Ute and Koppers, Benedikt and Butenweg, Christoph and Goemmel, Andreas and Utting, Jane F. and Schulz-Menger, Jeanette and Niendorf, Thoralf}, title = {Comparison of left ventricular function assessment using phonocardiogram- and electrocardiogram-triggered 2D SSFP CINE MR imaging at 1.5 T and 3.0 T}, series = {European Radiology}, volume = {20}, journal = {European Radiology}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084 (Onlineausgabe)}, doi = {10.1007/s00330-009-1676-z}, pages = {1344 -- 1355}, year = {2010}, abstract = {Objective: As high-field cardiac MRI (CMR) becomes more widespread the propensity of ECG to interference from electromagnetic fields (EMF) and to magneto-hydrodynamic (MHD) effects increases and with it the motivation for a CMR triggering alternative. This study explores the suitability of acoustic cardiac triggering (ACT) for left ventricular (LV) function assessment in healthy subjects (n=14). Methods: Quantitative analysis of 2D CINE steady-state free precession (SSFP) images was conducted to compare ACT's performance with vector ECG (VCG). Endocardial border sharpness (EBS) was examined paralleled by quantitative LV function assessment. Results: Unlike VCG, ACT provided signal traces free of interference from EMF or MHD effects. In the case of correct Rwave recognition, VCG-triggered 2D CINE SSFP was immune to cardiac motion effects—even at 3.0 T. However, VCG-triggered 2D SSFP CINE imaging was prone to cardiac motion and EBS degradation if R-wave misregistration occurred. ACT-triggered acquisitions yielded LV parameters (end-diastolic volume (EDV), endsystolic volume (ESV), stroke volume (SV), ejection fraction (EF) and left ventricular mass (LVM)) comparable with those derived fromVCG-triggered acquisitions (1.5 T: ESVVCG=(56± 17) ml, EDVVCG=(151±32)ml, LVMVCG=(97±27) g, SVVCG=(94± 19)ml, EFVCG=(63±5)\% cf. ESVACT= (56±18) ml, EDVACT=(147±36) ml, LVMACT=(102±29) g, SVACT=(91± 22) ml, EFACT=(62±6)\%; 3.0 T: ESVVCG=(55±21) ml, EDVVCG=(151±32) ml, LVMVCG=(101±27) g, SVVCG=(96±15) ml, EFVCG=(65±7)\% cf. ESVACT=(54±20) ml, EDVACT=(146±35) ml, LVMACT= (101±30) g, SVACT=(92±17) ml, EFACT=(64±6)\%). Conclusions: ACT's intrinsic insensitivity to interference from electromagnetic fields renders}, 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{EweKleinPieperetal.2009, author = {Ewe, Hendrik and Klein, Peter and Pieper, Martin and F{\"u}ldner, G.}, title = {Heat conductivity in sintered aluminium fibers}, series = {Cellular metals for structural and functional applications : CELLMET 2008 ; proceedings of the International Symposium on Cellular Metals for Structural and Functional Applications held October 8 - 10, 2008 in Dresden, Germany / ed. by G{\"u}nter Stephani}, journal = {Cellular metals for structural and functional applications : CELLMET 2008 ; proceedings of the International Symposium on Cellular Metals for Structural and Functional Applications held October 8 - 10, 2008 in Dresden, Germany / ed. by G{\"u}nter Stephani}, publisher = {Fraunhofer IFAM}, address = {Dresden}, pages = {187 -- 193}, year = {2009}, language = {en} } @article{SchwarzerdaSilvaHoffschmidtetal.2009, author = {Schwarzer, Klemens and da Silva, Vieira E. and Hoffschmidt, Bernhard and Schwarzer, T.}, title = {A new solar desalination system with heat recovery for decentralised drinking water production}, series = {Desalination. 248 (2009), H. 1-3}, journal = {Desalination. 248 (2009), H. 1-3}, publisher = {Elsevier}, address = {Amsterdam}, isbn = {0011-9164}, pages = {204 -- 211}, year = {2009}, language = {en} } @article{HoltschoppenButenwegMeskouris2009, author = {Holtschoppen, Britta and Butenweg, Christoph and Meskouris, Konstantin}, title = {Seismic design of non-structural components in industrial facilities}, series = {International journal of engineering under uncertainty}, volume = {Volume 1}, journal = {International journal of engineering under uncertainty}, issn = {0975-4806}, pages = {1 -- 13}, year = {2009}, language = {en} } @article{FrauenrathHezelHeinrichsetal.2009, author = {Frauenrath, Tobias and Hezel, Fabian and Heinrichs, Uwe and Kozerke, Sebastian and Utting, Jane and Kob, Malte and Butenweg, Christoph and Boesiger, Peter and Niendorf, Thoralf}, title = {Feasibility of Cardiac Gating Free of Interference With Electro-Magnetic Fields at 1.5 Tesla, 3.0 Tesla and 7.0 Tesla Using an MR-Stethoscope}, series = {Investigative Radiology}, volume = {44}, journal = {Investigative Radiology}, number = {9}, publisher = {Lippincott Williams \& Wilkins ; (via Ovid)}, address = {Philadelphia, Pa}, issn = {1536-0210 (online)}, doi = {10.1097/RLI.0b013e3181b4c15e}, pages = {539 -- 547}, year = {2009}, language = {en} } @article{SchwarzerSilva2008, author = {Schwarzer, Klemens and Silva, Maria Eugenia Vieira da}, title = {Characterisation and design methods of solar cookers / Schwarzer, Klemens ; Silva, Maria Eugenia Vieira da}, series = {Solar energy. 82 (2008), H. 2}, journal = {Solar energy. 82 (2008), H. 2}, isbn = {0038-092X}, pages = {157 -- 163}, year = {2008}, 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{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{AlexopoulosBreitbachHoffschmidtetal.2008, author = {Alexopoulos, Spiros and Breitbach, Gerd and Hoffschmidt, Bernhard and Stobbe, P.}, title = {Optimization of the geometry of porous SiC ceramic filtering modules using numerical methods}, series = {Developments in porous, biological and geopolymer ceramics : a collection of papers presented at the 31st International Conference on Advanced Ceramics and Composites, January 21 - 26, 2007, Daytona Beach, Florida ; [papers presented at the Symposium on Porous Ceramics: Novel Developments and Applications] / ed.: Manuel Brito ... Vol. ed.: Jonathan Salem ... The American Ceramics Society}, journal = {Developments in porous, biological and geopolymer ceramics : a collection of papers presented at the 31st International Conference on Advanced Ceramics and Composites, January 21 - 26, 2007, Daytona Beach, Florida ; [papers presented at the Symposium on Porous Ceramics: Novel Developments and Applications] / ed.: Manuel Brito ... Vol. ed.: Jonathan Salem ... The American Ceramics Society}, publisher = {Wiley}, address = {Hoboken, NJ}, isbn = {9780470196403}, pages = {95 -- 104}, year = {2008}, language = {en} } @article{HelsperHornSchneideretal.2008, author = {Helsper, Christoph and Horn, Hans-Georg and Schneider, Friedhelm and Wehner, Birgit}, title = {Intercomparison of five mobility size spectrometers for measuring atmospheric submicrometer aerosol particles / Helsper, Christoph ; Horn, Hans-Georg ; Schneider, Friedhelm ; Wehner, Birgit ; Wiedensohler, Alfred}, series = {Gefahrstoffe, Reinhaltung der Luft. Air Quality Control. 68 (2008), H. 11-12}, journal = {Gefahrstoffe, Reinhaltung der Luft. Air Quality Control. 68 (2008), H. 11-12}, isbn = {0949-8036}, pages = {475 -- 481}, year = {2008}, language = {en} } @article{AlexopoulosBreitbachHoffschmidtetal.2008, author = {Alexopoulos, Spiros and Breitbach, Gerd and Hoffschmidt, Bernhard and Stobbe, P.}, title = {Computational fluid flow of porous resic ceramic filtering modules and optimization of the channel edge form geometry}, series = {Proceedings : April 14 - 18, 2008, Leipzig, Germany / hosted by VDI, Society for Chemical and Process Engineering . Vol 2}, journal = {Proceedings : April 14 - 18, 2008, Leipzig, Germany / hosted by VDI, Society for Chemical and Process Engineering . Vol 2}, publisher = {Filtech Exhibitions}, address = {Meerbusch}, pages = {300 -- 304}, year = {2008}, 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{MahmoudiFleischhakerSahraietal.2008, author = {Mahmoudi, Mohammad and Fleischhaker, Robert and Sahrai, Mostafa and Evers, J{\"o}rg}, title = {Group velocity control in the ultraviolet domain via interacting dark-state resonances}, series = {Journal of physics B: Atomic, molecular and optical physics}, volume = {41}, journal = {Journal of physics B: Atomic, molecular and optical physics}, number = {2}, issn = {0953-4075}, doi = {10.1088/0953-4075/41/2/025504}, pages = {25504 -- 25600}, year = {2008}, language = {en} } @article{FleischhakerEvers2008, author = {Fleischhaker, Robert and Evers, J{\"o}rg}, title = {Nonlinear effects in pulse propagation through Doppler-broadened closed-loop atomic media}, series = {Physical Review A - Atomic, molecular, and optical physics}, volume = {77}, journal = {Physical Review A - Atomic, molecular, and optical physics}, number = {4}, issn = {1050-2947}, doi = {10.1103/PhysRevA.77.043805}, pages = {043805}, year = {2008}, language = {en} } @article{FleischhakerEvers2008, author = {Fleischhaker, Robert and Evers, J{\"o}rg}, title = {Four-wave mixing enhanced white-light cavity}, series = {Physical Review A - Atomic, molecular, and optical physics}, volume = {78}, journal = {Physical Review A - Atomic, molecular, and optical physics}, number = {5}, issn = {0556-2791}, pages = {051802(R)}, year = {2008}, language = {en} } @article{BaumgartnerFidlerWethetal.2008, author = {Baumgartner, Werner and Fidler, Florian and Weth, Agnes and Habbecke, Martin and Jakob, Peter and Butenweg, Christoph and B{\"o}hme, Wolfgang}, title = {Investigating the locomotion of the sandfish in desert sand using NMR-Imaging}, series = {PLOS ONE}, volume = {3}, journal = {PLOS ONE}, number = {10}, publisher = {Plos}, address = {San Francisco, California, US}, issn = {1932-6203}, doi = {10.1371/journal.pone.0003309}, pages = {e3309}, year = {2008}, abstract = {The sandfish (Scincus scincus) is a lizard having the remarkable ability to move through desert sand for significant distances. It is well adapted to living in loose sand by virtue of a combination of morphological and behavioural specializations. We investigated the bodyform of the sandfish using 3D-laserscanning and explored its locomotion in loose desert sand using fast nuclear magnetic resonance (NMR) imaging. The sandfish exhibits an in-plane meandering motion with a frequency of about 3 Hz and an amplitude of about half its body length accompanied by swimming-like (or trotting) movements of its limbs. No torsion of the body was observed, a movement required for a digging-behaviour. Simple calculations based on the Janssen model for granular material related to our findings on bodyform and locomotor behaviour render a local decompaction of the sand surrounding the moving sandfish very likely. Thus the sand locally behaves as a viscous fluid and not as a solid material. In this fluidised sand the sandfish is able to "swim" using its limbs.}, language = {en} } @article{FoersterLepsaFreundt2007, author = {F{\"o}rster, Arnold and Lepsa, M. I. and Freundt, D.}, title = {Hot electron injector Gunn diode for advanced driver assistance systems}, series = {Applied physics A: materials science and processing. 87 (2007), H. 3}, journal = {Applied physics A: materials science and processing. 87 (2007), H. 3}, isbn = {0947-8396}, pages = {545 -- 558}, year = {2007}, language = {en} }