@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} } @inproceedings{KerpenBungSchlurmann2010, author = {Kerpen, N. B. and Bung, Daniel Bernhard and Schlurmann, Torsten}, title = {Physical model investigations of pressure distributions next to ships passing through a lock}, series = {5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010}, booktitle = {5th Chinese-German Joint Symposium on Hydraulic and Ocean Engineering : CG JOINT 2010}, publisher = {Univ. Press}, address = {Tianjin}, organization = {Chinese-German Joint Symposium on Hydraulic and Ocean Engineering <5, 2010, Tianjin>}, isbn = {978-7-5618-3671-2}, pages = {514 -- 519}, year = {2010}, language = {en} } @inproceedings{KerpenBungSchlurmann2010, author = {Kerpen, N. B. and Bung, Daniel Bernhard and Schlurmann, Torsten}, title = {Physical model investigations of ships passing through a lock}, series = {Hydraulic structures: useful water harvesting systems or relics? : Third International Junior Researcher and Engineer Workshop on Hydraulic Structures (IJREWHS'10) : Edinburgh, Scotland, U.K., 2-3 May 2010}, booktitle = {Hydraulic structures: useful water harvesting systems or relics? : Third International Junior Researcher and Engineer Workshop on Hydraulic Structures (IJREWHS'10) : Edinburgh, Scotland, U.K., 2-3 May 2010}, editor = {Janssen, Robert}, publisher = {School of Civil Engineeering, The University of Queensland}, address = {Brisbane}, organization = {International Junior Researcher and Engineer Workshop on Hydraulic Structures <3, 2010, Edinburgh>}, isbn = {9781742720159}, pages = {93 -- 100}, year = {2010}, language = {en} } @article{ArampatzisPeperBierbaumetal.2010, author = {Arampatzis, Adamantios and Peper, Andreas and Bierbaum, Stefanie and Albracht, Kirsten}, title = {Plasticity of human Achilles tendon mechanical and morphological properties in response to cyclic strain}, series = {Journal of Biomechanics}, volume = {43}, journal = {Journal of Biomechanics}, number = {16}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0021-9290}, doi = {10.1016/j.jbiomech.2010.08.014}, pages = {3073 -- 3079}, year = {2010}, abstract = {The purpose of the current study in combination with our previous published data (Arampatzis et al., 2007) was to examine the effects of a controlled modulation of strain magnitude and strain frequency applied to the Achilles tendon on the plasticity of tendon mechanical and morphological properties. Eleven male adults (23.9±2.2 yr) participated in the study. The participants exercised one leg at low magnitude tendon strain (2.97±0.47\%), and the other leg at high tendon strain magnitude (4.72±1.08\%) of similar frequency (0.5 Hz, 1 s loading, 1 s relaxation) and exercise volume (integral of the plantar flexion moment over time) for 14 weeks, 4 days per week, 5 sets per session. The exercise volume was similar to the intervention of our earlier study (0.17 Hz frequency; 3 s loading, 3 s relaxation) allowing a direct comparison of the results. Before and after the intervention ankle joint moment has been measured by a dynamometer, tendon-aponeurosis elongation by ultrasound and cross-sectional area of the Achilles tendon by magnet resonance images (MRI). We found a decrease in strain at a given tendon force, an increase in tendon-aponeurosis stiffness and tendon elastic modulus of the Achilles tendon only in the leg exercised at high strain magnitude. The cross-sectional area (CSA) of the Achilles tendon did not show any statistically significant (P>0.05) differences to the pre-exercise values in both legs. The results indicate a superior improvement in tendon properties (stiffness, elastic modulus and CSA) at the low frequency (0.17 Hz) compared to the high strain frequency (0.5 Hz) protocol. These findings provide evidence that the strain magnitude applied to the Achilles tendon should exceed the value, which occurs during habitual activities to trigger adaptational effects and that higher tendon strain duration per contraction leads to superior tendon adaptational responses.}, 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}, publisher = {IEEE}, address = {New York}, isbn = {978-88-905519-0-1}, doi = {10.1109/ICLP.2010.7845757}, pages = {750-1 -- 750-8}, year = {2010}, abstract = {Planning the air-terminations for a structure to be protected the use of the rolling-sphere method (electro-geometrical model) is the best way from the physics of lightning point-of-view. Therefore, international standards prefer this method. However, using the rolling-sphere method only results in possible point-of-strikes on a structure without giving information about the probability of strikes at the individual points compared to others.}, language = {en} } @article{ChristenKowalskiBartelt2010, author = {Christen, Marc and Kowalski, Julia and Bartelt, Perry}, title = {RAMMS: Numerical simulation of dense snow avalanches in three-dimensional terrain}, series = {Cold Regions Science and Technology}, volume = {63}, journal = {Cold Regions Science and Technology}, number = {1-2}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1872-7441}, doi = {10.1016/j.coldregions.2010.04.005}, pages = {1 -- 14}, year = {2010}, abstract = {Numerical avalanche dynamics models have become an essential part of snow engineering. Coupled with field observations and historical records, they are especially helpful in understanding avalanche flow in complex terrain. However, their application poses several new challenges to avalanche engineers. A detailed understanding of the avalanche phenomena is required to construct hazard scenarios which involve the careful specification of initial conditions (release zone location and dimensions) and definition of appropriate friction parameters. The interpretation of simulation results requires an understanding of the numerical solution schemes and easy to use visualization tools. We discuss these problems by presenting the computer model RAMMS, which was specially designed by the SLF as a practical tool for avalanche engineers. RAMMS solves the depth-averaged equations governing avalanche flow with accurate second-order numerical solution schemes. The model allows the specification of multiple release zones in three-dimensional terrain. Snow cover entrainment is considered. Furthermore, two different flow rheologies can be applied: the standard Voellmy-Salm (VS) approach or a random kinetic energy (RKE) model, which accounts for the random motion and inelastic interaction between snow granules. We present the governing differential equations, highlight some of the input and output features of RAMMS and then apply the models with entrainment to simulate two well-documented avalanche events recorded at the Vall{\´e}e de la Sionne test site.}, language = {en} } @article{PaulssenSchweighoeferAbram2010, author = {Paulßen, Elisabeth and Schweigh{\"o}fer, Philip V. and Abram, Ulrich}, title = {Reactions of [ReOX3(PPh3)2] Complexes (X = Cl, Br) with Phenylacetylene and the Structures of the Products}, series = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie : ZAAC = Journal of inorganic and general chemistry}, volume = {636}, journal = {Zeitschrift f{\"u}r anorganische und allgemeine Chemie : ZAAC = Journal of inorganic and general chemistry}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-3749}, doi = {10.1002/zaac.200900478}, pages = {779 -- 783}, year = {2010}, abstract = {Oxorhenium(V) complexes [ReOX3(PPh3)2] (X = Cl, Br) react with phenylacetylene under formation of complexes with ylide-type ligands. Compounds of the compositions [ReOCl3(PPh3){C(Ph)C(H)(PPh3)}] (1), [ReOBr3(OPPh3){C(Ph)C(H)(PPh3)}] (2), and [ReOBr3(OPPh3){C(H)C(Ph)(PPh3)}] (3) were isolated and characterized by X-ray diffraction. They contain a ligand, which was formed by a nucleophilic attack of released PPh3 at coordinated phenylacetylene. The structures of the products show that there is no preferable position for this attack. Cleavage of the Re-C bond in 3 and dimerization of the organic ligand resulted in the formation of the [{(PPh3)(H)CC(Ph)}2]2+ cation, which crystallized as its [(ReOBr4)(OReO3)]2- salt.}, language = {en} } @article{BohrnStuetzFleischeretal.2010, author = {Bohrn, Ulrich and St{\"u}tz, Evamaria and Fleischer, Maximilian and Sch{\"o}ning, Michael Josef}, title = {Real-time detection of CO by eukaryotic cells}, series = {Procedia Engineering}, volume = {5}, journal = {Procedia Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1877-7058}, pages = {17 -- 20}, year = {2010}, abstract = {In this contribution, we focus on the detection of toxic gases with living eukaryotic cells. A cell-based gas sensor system, able to measure the effects of direct exposure of gases to cells in real-time, was set up. Impedance data as well as oxygen consumption of Chinese hamster lung fibroblast cells (V79) were analysed upon exposure to carbon monoxide (CO). The CO (diluted in wet synthetic air) affects the cell respiration as indicated by an attenuated respiration signal after the CO exposure as well as an instant increase of the capacitive part of the impedance signal during the gas exposure.}, language = {en} } @article{KirchnerOberlaenderFriedrichetal.2010, author = {Kirchner, Patrick and Oberl{\"a}nder, Jan and Friedrich, Peter and Rysstad, Gunnar and Berger, J{\"o}rg and Keusgen, Michael and Sch{\"o}ning, Michael Josef}, title = {Realization of a calorimetric gas sensor on polyimide foil for applications in aseptic food industry}, series = {Procedia Engineering}, volume = {5}, journal = {Procedia Engineering}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1877-7058}, doi = {10.1016/j.proeng.2010.09.098}, pages = {264 -- 267}, year = {2010}, abstract = {A calorimetric gas sensor is presented for the monitoring of gas-phase H2O2 at elevated temperature during sterilization processes in aseptic food industry. The sensor consists of two temperature-sensitive thin-film resistances built up on a polyimide foil with a thickness of 25 μm, which are passivated with a layer of SU-8 photo resist and catalytically activated with manganese(IV) oxide. Instead of an active heating structure, the calorimetric sensor utilizes the elevated temperature of an evaporated H2O2 aerosol. In an experimental set-up, the sensor has shown a sensitivity of 4.78 °C/(\%v/v) in a H2O2 concentration range of 0 to 10\% v/v at an evaporation temperature of 240 ∘C. Furthermore, the sensor possesses the same, unchanged sensor signal even at varied evaporation temperatures of the gas stream. The sensor characterization demonstrates the suitability of the calorimetric gas sensor for monitoring the efficiency of sterilization processes.}, 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} }