TY - JOUR A1 - Förster, Arnold A1 - Schäfer, B.-J. A1 - Londschien, M. T1 - Arsenic passivation of MOMBE grown GaAs surfaces / B. -J. Schäfer ; A. Förster ; M. Londschien ... JF - Surface Science. 204 (1988), H. 3 Y1 - 1988 SN - 0039-6028 N1 - ISSN der E-Ausg.: 0039-6028 SP - 485 EP - 490 ER - TY - JOUR A1 - Förster, Arnold A1 - Resch, U. A1 - Essera, N. A1 - Raptis, Y. S. T1 - Arsenic passivation of MBE grown GaAs(100): structural and electronic properties of the decapped surfaces / U. Resch ; N. Essera ; Y. S. Raptis ... A. Förster ... JF - Surface Science. 269-270 (1992) Y1 - 1992 SN - 0039-6028 N1 - ISSN der E-Ausg.: 0039-6028 SP - 797 EP - 803 ER - TY - JOUR A1 - Pieper, Martin A1 - Klein, Peter T1 - Application of simple, periodic homogenization techniques to non-linear heat conduction problems in non-periodic, porous media JF - Heat mass transfer N2 - 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. Y1 - 2012 U6 - http://dx.doi.org/10.1007/s00231-011-0879-4 SN - 0947-7411 VL - 48 IS - 2 SP - 291 EP - 300 PB - Springer CY - Berlin ER - TY - JOUR A1 - Helsper, Christoph A1 - Nießner, R. A1 - Rönicke, G. T1 - Application of a Multistep Condensation Nuclei Counter as a Detector for Particle Surface Composition / Nießner, R.; Helsper, C.; Rönicke, G. JF - Aerosols : science, technology, and industr. applications of airborne particles ; proceedings of the 1. Internat. Aerosol Conference held Sept. 17-21, 1984, Minneapolis, Minn., U.S.A / ed.: Benjamin Y. H. Liu Y1 - 1984 SN - 0444009477 N1 - International Aerosol Conference ; (1, 1984, Minneapolis, Minn.) SP - 63 EP - 66 PB - Elsevier CY - New York [u.a.] ER - TY - JOUR A1 - Helsper, Christoph A1 - Nießner, R. T1 - Application of a Multistep Condensation Nuclei Counter as a Detector for Particle Surface Composition / Nießner, R. ; Helsper, C. JF - Journal of Aerosol Science. 16 (1985), H. 3 Y1 - 1985 SN - 0021-8502 SP - 201 EP - 209 ER - TY - JOUR A1 - Förster, Arnold A1 - Darmo, J. A1 - Dubecky, F. A1 - Kordos, P. T1 - Annealing effect on concentration of EL6-like deep-level state in low-temperature-grown molecular beam epitaxial GaAs. Darmo, J.; Dubecky, F.; Kordos, P.; Förster, A. JF - Applied Physics Letters. 72 (1998), H. 5 Y1 - 1998 SN - 1077-3118 SP - 590 EP - 592 ER - TY - JOUR A1 - Förster, Arnold A1 - Darmo, J. A1 - Dubecký, F. A1 - Kordos, P. T1 - Annealing characteristics of native defects in low-temperature-grown MBE GaAs / J. Darmo ; F. Dubecky ; P. Kordos ; A. Förster JF - Semiconducting and insulating materials 1996 : proceedings of the 9th Conference on Semiconducting and Insulating Materials (SIMC '9), April 29 - May 3, 1996, Toulouse, France / [IEEE] Y1 - 1996 SN - 0-7803-3095-1 N1 - 2. ISBN: 0-7803-3179-6 ; Conference on Semiconducting and Insulating Materials <9, 1996, Toulouse> ; Institute of Electrical and Electronics Engineers ; IEEE Cat. No.96CH35881 SP - 67 EP - ff. CY - Piscataway, NJ [u.a.] ER - TY - JOUR A1 - Barsov, S. A1 - Bechstedt, U. A1 - Hardt, Arno T1 - ANKE, a new facility for medium energy hadron physics at COSY-Jülich / S. Barsov [u.a.] JF - Nuclear instruments and methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment. Vol. 462, iss. 3 Y1 - 2001 SN - 0167-5087 (Print) ; 0168-9002 (E-journal) SP - 364 EP - 381 ER - TY - JOUR A1 - Butenweg, Christoph A1 - Rosin, Julia A1 - Holler, Stefan T1 - Analysis of cylindrical granular material silos under seismic excitation JF - Buildings N2 - Silos generally work as storage structures between supply and demand for various goods, and their structural safety has long been of interest to the civil engineering profession. This is especially true for dynamically loaded silos, e.g., in case of seismic excitation. Particularly thin-walled cylindrical silos are highly vulnerable to seismic induced pressures, which can cause critical buckling phenomena of the silo shell. The analysis of silos can be carried out in two different ways. In the first, the seismic loading is modeled through statically equivalent loads acting on the shell. Alternatively, a time history analysis might be carried out, in which nonlinear phenomena due to the filling as well as the interaction between the shell and the granular material are taken into account. The paper presents a comparison of these approaches. The model used for the nonlinear time history analysis considers the granular material by means of the intergranular strain approach for hypoplasticity theory. The interaction effects between the granular material and the shell is represented by contact elements. Additionally, soil–structure interaction effects are taken into account. KW - granular silo KW - earthquake engineering KW - hypoplasticity KW - nonlinear transient analyses Y1 - 2017 U6 - http://dx.doi.org/10.3390/buildings7030061 SN - 2075-5309 VL - 7 IS - 3 SP - 1 EP - 12 PB - MDPI CY - Basel ER - TY - JOUR A1 - Maurer, Florian A1 - Rieke, Christian A1 - Schemm, Ralf A1 - Stollenwerk, Dominik T1 - Analysis of an urban grid with high photovoltaic and e-mobility penetration JF - Energies N2 - This study analyses the expected utilization of an urban distribution grid under high penetration of photovoltaic and e-mobility with charging infrastructure on a residential level. The grid utilization and the corresponding power flow are evaluated, while varying the control strategies and photovoltaic installed capacity in different scenarios. Four scenarios are used to analyze the impact of e-mobility. The individual mobility demand is modelled based on the largest German studies on mobility “Mobilität in Deutschland”, which is carried out every 5 years. To estimate the ramp-up of photovoltaic generation, a potential analysis of the roof surfaces in the supply area is carried out via an evaluation of an open solar potential study. The photovoltaic feed-in time series is derived individually for each installed system in a resolution of 15 min. The residential consumption is estimated using historical smart meter data, which are collected in London between 2012 and 2014. For a realistic charging demand, each residential household decides daily on the state of charge if their vehicle requires to be charged. The resulting charging time series depends on the underlying behavior scenario. Market prices and mobility demand are therefore used as scenario input parameters for a utility function based on the current state of charge to model individual behavior. The aggregated electricity demand is the starting point of the power flow calculation. The evaluation is carried out for an urban region with approximately 3100 residents. The analysis shows that increased penetration of photovoltaics combined with a flexible and adaptive charging strategy can maximize PV usage and reduce the need for congestion-related intervention by the grid operator by reducing the amount of kWh charged from the grid by 30% which reduces the average price of a charged kWh by 35% to 14 ct/kWh from 21.8 ct/kWh without PV optimization. The resulting grid congestions are managed by implementing an intelligent price or control signal. The analysis took place using data from a real German grid with 10 subgrids. The entire software can be adapted for the analysis of different distribution grids and is publicly available as an open-source software library on GitHub. KW - distribution grid simulation KW - smart-charging KW - e-mobility Y1 - 2023 U6 - http://dx.doi.org/10.3390/en16083380 SN - 1996-1073 N1 - This article belongs to the Special Issue "Advanced Solutions for the Efficient Integration of Electric Vehicles in Electricity Grids" N1 - Corresponding author: Florian Maurer VL - 16 IS - 8 PB - MDPI CY - Basel ER -