@article{YazdanbakhshSolbachBitz2012, author = {Yazdanbakhsh, Pedram and Solbach, Klaus and Bitz, Andreas}, title = {Variable power combiner for RF mode shimming in 7-T MR imaging}, series = {IEEE Transaction on Biomedical Engineering}, volume = {59}, journal = {IEEE Transaction on Biomedical Engineering}, number = {9}, publisher = {IEEE}, address = {New York}, issn = {1558-2531}, doi = {10.1109/TBME.2012.2205926}, pages = {2549 -- 2557}, year = {2012}, abstract = {This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers' input signals. The power distribution at the output ports of the VPC is then fed into the "mode" ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17\% to 60\% and from 14\% to 55\% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.}, language = {en} } @article{KrollLudwigs2012, author = {Kroll-Ludwigs, Kathrin}, title = {Ein optionales Vertragsrecht f{\"u}r Europa: Motor oder Hemmnis f{\"u}r den Binnenmarkt?}, series = {GPR : Zeitschrift f{\"u}r Gemeinschaftsprivatrecht}, volume = {9}, journal = {GPR : Zeitschrift f{\"u}r Gemeinschaftsprivatrecht}, number = {4}, publisher = {Verlag Dr. Otto Schmidt}, address = {K{\"o}ln}, issn = {2193-9519}, doi = {10.1515/gpr.2012.9.4.181}, pages = {181 -- 188}, year = {2012}, language = {de} } @article{ChludekTran2012, author = {Chludek, Astrid and Tran, Duc Hung}, title = {Der Reformvorschlag des IAS 12 gem. ED/2009/2 - Ein Pl{\"a}doyer f{\"u}r die Einf{\"u}hrung der valuation allowance}, series = {KoR Zeitschrift f{\"u}r kapitalmarktorientierte Rechnungslegung}, journal = {KoR Zeitschrift f{\"u}r kapitalmarktorientierte Rechnungslegung}, number = {1}, publisher = {Fachmedien Otto Schmidt}, address = {D{\"u}sseldorf}, issn = {1617-8084}, pages = {4 -- 8}, year = {2012}, language = {de} } @article{HerzwurmKramsPietschetal.2012, author = {Herzwurm, Georg and Krams, Benedikt and Pietsch, Wolfram and Schockert, Sixten}, title = {Report from the 3rd international workshop on requirements prioritization for customer oriented software development (RePriCo'12)}, series = {ACM SIGSOFT Software Engineering Notes}, volume = {37}, journal = {ACM SIGSOFT Software Engineering Notes}, number = {4}, publisher = {Association for Computing Machinery}, address = {New York}, issn = {0163-5948}, doi = {10.1145/2237796.2237817}, pages = {32 -- 34}, year = {2012}, abstract = {Prioritization is an essential task within requirements engineering to cope with complexity and to establish focus properly. The 3rd Workshop on Requirements Prioritization for customer oriented Software Development (RePriCo'12) focused on requirements prioritization and adjacent themes in the context of customer oriented development of bespoke and standard software. Five submissions have been accepted for the proceedings and for presentation. The report summarizes and points out key findings.}, language = {en} } @article{Alexopoulos2012, author = {Alexopoulos, Spiros}, title = {Biogas systems: basics, biogas multifunction, principle of fermentation and hybrid application with a solar tower for the treatment of waste animal manure}, series = {Journal of Engineering Science and Technology Review}, volume = {5}, journal = {Journal of Engineering Science and Technology Review}, number = {4}, issn = {1791-2377}, pages = {48 -- 55}, year = {2012}, abstract = {Two of the main environmental problems of today's society are the continuously increasing production of organic wastes as well as the increase of carbon dioxide in the atmosphere and the related green house effect. A way to solve these problems is the production of biogas. Biogas is a combustible gas consisting of methane, carbon dioxide and small amounts of other gases and trace elements. Production of biogas through anaerobic digestion of animal manure and slurries as well as of a wide range of digestible organic wastes and agricultural residues, converts these substrates into electricity and heat and offers a natural fertiliser for agriculture. The microbiological process of decomposition of organic matter, in the absence of oxygen takes place in reactors, called digesters. Biogas can be used as a fuel in a gas turbine or burner and can be used in a hybrid solar tower system offering a solution for waste treatment of agricultural and animal residues. A solar tower system consists of a heliostat field, which concentrates direct solar irradiation on an open volumetric central receiver. The receiver heats up ambient air to temperatures of around 700°C. The hot air's heat energy is transferred to a steam Rankine cycle in a heat recovery steam generator (HRSG). The steam drives a steam turbine, which in turn drives a generator for producing electricity. In order to increase the operational hours of a solar tower power plant, a heat storage system and/ or hybridization may be considered. The advantage of solar-fossil hybrid power plants, compared to solar-only systems, lies in low additional investment costs due to an adaptable solar share and reduced technical and economical risks. On sunny days the hybrid system operates in a solar-only mode with the central receiver and on cloudy days and at night with the gas turbine only. As an alternative to methane gas, environmentally neutral biogas can be used for operating the gas turbine. Hence, the hybrid system is operated to 100\% from renewable energy sources}, language = {en} } @article{StadlerGarveyBocahutetal.2012, author = {Stadler, Andreas M. and Garvey, G. J. and Bocahut, A. and Sacquin-Mora, S. and Digel, Ilya and Schneider, G. J. and Natali, F. and Artmann, Gerhard and Zaccai, G.}, title = {Thermal fluctuations of haemoglobin from different species : adaptation to temperature via conformational dynamics}, series = {Journal of the Royal Society Interface}, volume = {9}, journal = {Journal of the Royal Society Interface}, number = {76}, publisher = {The Royal Society}, address = {London}, issn = {1742-5689}, doi = {10.1098/rsif.2012.0364}, pages = {2845 -- 2855}, year = {2012}, abstract = {Thermodynamic stability, configurational motions and internal forces of haemoglobin (Hb) of three endotherms (platypus, Ornithorhynchus anatinus; domestic chicken, Gallus gallus domesticus and human, Homo sapiens) and an ectotherm (salt water crocodile, Crocodylus porosus) were investigated using circular dichroism, incoherent elastic neutron scattering and coarse-grained Brownian dynamics simulations. The experimental results from Hb solutions revealed a direct correlation between protein resilience, melting temperature and average body temperature of the different species on the 0.1 ns time scale. Molecular forces appeared to be adapted to permit conformational fluctuations with a root mean square displacement close to 1.2 {\AA} at the corresponding average body temperature of the endotherms. Strong forces within crocodile Hb maintain the amplitudes of motion within a narrow limit over the entire temperature range in which the animal lives. In fully hydrated powder samples of human and chicken, Hb mean square displacements and effective force constants on the 1 ns time scale showed no differences over the whole temperature range from 10 to 300 K, in contrast to the solution case. A complementary result of the study, therefore, is that one hydration layer is not sufficient to activate all conformational fluctuations of Hb in the pico- to nanosecond time scale which might be relevant for biological function. Coarse-grained Brownian dynamics simulations permitted to explore residue-specific effects. They indicated that temperature sensing of human and chicken Hb occurs mainly at residues lining internal cavities in the β-subunits.}, language = {en} } @article{ButenwegFehling2012, author = {Butenweg, Christoph and Fehling, Ekkehard}, title = {Hintergrund f{\"u}r die vereinfachten Regeln bei Mauerwerksgeb{\"a}uden im Erdbebenfall}, series = {Mauerwerk : European journal of masonry}, volume = {Volume 16}, journal = {Mauerwerk : European journal of masonry}, number = {Issue 3}, publisher = {Wiley}, address = {Weinheim}, issn = {1437-1022 (E-Journal); 1432-3427 (Print)}, doi = {10.1002/dama.201200537}, pages = {127 -- 137}, year = {2012}, abstract = {Bei der Ausarbeitung des nationalen Anwendungsdokumentes zur DIN EN 1998-1 waren die in der ENV-Fassung enthaltenen vereinfachten Regeln im Lichte aktueller Forschungsergebnisse zu {\"u}berpr{\"u}fen und zu {\"u}berarbeiten. Die gleiche Aufgabe stellte sich auch f{\"u}r die Neufassung der DIN 4149. In beiden F{\"a}llen sind neben konstruktiven Regeln f{\"u}r die Art und Anordnung der zur Geb{\"a}udeaussteifung heranzuziehenden W{\"a}nde im Grundriss Tabellen enthalten, die unter bestimmten Bedingungen den Entfall eines rechnerischen Nachweises der Tragw{\"a}nde im Erdbebenfall erm{\"o}glichen. Dies ist f{\"u}r Schwachbebengebiete, wie sie in Deutschland und anderen L{\"a}ndern Mitteleuropas anzutreffen sind, sinnvoll, um unn{\"o}tigen Rechenaufwand sowie Probleme mit der F{\"u}hrbarkeit von Nachweisen so weit wie m{\"o}glich auszuschalten. Im vorliegenden Beitrag werden die Hintergr{\"u}nde der vereinfachten Regeln diskutiert und die Ergebnisse der Anwendung mit verschiedenen Rechenverfahren verglichen und bewertet.}, language = {de} } @article{ButenwegGellert2012, author = {Butenweg, Christoph and Gellert, Christoph}, title = {Integrale Geb{\"a}udeplanung am Beispiel eines Geschossbaus in Ziegelmauerwerk}, series = {Mauerwerk : European journal of masonry}, volume = {Volume 16}, journal = {Mauerwerk : European journal of masonry}, number = {5}, publisher = {Wiley}, address = {Weinheim}, issn = {1437-1022 (E-Journal); 1432-3427 (Print)}, doi = {10.1002/dama.201200550}, pages = {247 -- 254}, year = {2012}, abstract = {Moderne Mauerwerksbauten m{\"u}ssen nach heutigen Anforderungen architektonisch, statisch, energetisch sowie schall- und brandschutztechnisch optimal ausgelegt sein. Aufgrund der Komplexit{\"a}t und engen Verzahnung der einzelnen Anforderungen ist eine integrale Geb{\"a}udeplanung zur Erzielung einer qualitativ hochwertigen Bauwerksl{\"o}sung unbedingt notwendig. Diese erfordert von den Fachplanern vertieftes Spezialwissen in den verschiedenen Bereichen, um insbesondere die Schnittstellen und Bauwerksdetails korrekt zu planen und auszuf{\"u}hren. Der Beitrag stellt die integrale Geb{\"a}udeplanung am Beispiel eines Geschossbaus in Ziegelbauweise mit L{\"o}sungen f{\"u}r wesentliche Detailpunkte vor}, language = {de} } @article{ButenwegHoltschoppen2012, author = {Butenweg, Christoph and Holtschoppen, Britta}, title = {Neuer VCI-Leitfaden f{\"u}r die erdbebensichere Auslegung von Industrieanlagen}, series = {Bauingenieur : die richtungsweisende Zeitschrift im Bauingenieurswesen ; offizielle Zeitschrift der VDI-Gesellschaft Bautechnik}, volume = {Band 87}, journal = {Bauingenieur : die richtungsweisende Zeitschrift im Bauingenieurswesen ; offizielle Zeitschrift der VDI-Gesellschaft Bautechnik}, publisher = {VDI Fachmedien}, address = {D{\"u}sseldorf}, issn = {1436-4867 (E-Journal); 0005-6650 (Print)}, pages = {S18}, year = {2012}, language = {de} } @article{LoebSchartnerDachwaldetal.2012, author = {Loeb, Horst Wolfgang and Schartner, Karl-Heinz and Dachwald, Bernd and Ohndorf, Andreas and Seboldt, Wolfgang}, title = {Interstellar heliopause probe}, series = {Труды МАИ}, journal = {Труды МАИ}, number = {60}, publisher = {Moskauer Staatliches Luftfahrtinstitut (МАИ)}, address = {Moskau}, pages = {2 -- 2}, year = {2012}, abstract = {There is common agreement within the scientific community that in order to understand our local galactic environment it will be necessary to send a spacecraft into the region beyond the solar wind termination shock. Considering distances of 200 AU for a new mission, one needs a spacecraft traveling at a speed of close to 10 AU/yr in order to keep the mission duration in the range of less than 25 yrs, a transfer time postulated by European Space Agency (ESA). Two propulsion options for the mission have been proposed and discussed so far: the solar sail propulsion and the ballistic/radioisotope-electric propulsion (REP). As a further alternative, we here investigate a combination of solar-electric propulsion (SEP) and REP. The SEP stage consists of six 22-cms diameter RIT-22 ion thrusters working with a high specific impulse of 7377 s corresponding to a positive grid voltage of 5 kV. Solar power of 53 kW at begin of mission (BOM) is provided by a lightweight solar array.}, language = {en} }