@article{BragardSoltauThomasetal.2010, author = {Bragard, Michael and Soltau, N. and Thomas, S. and De Doncker, R. W.}, title = {The balance of renewable sources and user demands in grids : power electronics for modular battery energy storage systems}, series = {IEEE transactions on power electronics}, volume = {25}, journal = {IEEE transactions on power electronics}, number = {12}, publisher = {IEEE}, address = {New York}, issn = {0885-8993}, doi = {10.1109/TPEL.2010.2085455}, pages = {3049 -- 3056}, year = {2010}, abstract = {The continuously growing amount of renewable sources starts compromising the stability of electrical grids. Contradictory to fossil fuel power plants, energy production of wind and photovoltaic (PV) energy is fluctuating. Although predictions have significantly improved, an outage of multi-MW offshore wind farms poses a challenging problem. One solution could be the integration of storage systems in the grid. After a short overview, this paper focuses on two exemplary battery storage systems, including the required power electronics. The grid integration, as well as the optimal usage of volatile energy reserves, is presented for a 5- kW PV system for home application, as well as for a 100- MW medium-voltage system, intended for wind farm usage. The efficiency and cost of topologies are investigated as a key parameter for large-scale integration of renewable power at medium- and low-voltage.}, language = {en} } @article{EilmannBuchmannSiegwolfetal.2010, author = {Eilmann, Britta and Buchmann, Nina and Siegwolf, Rolf and Saurer, Matthias and Cherubini, Paolo and Rigling, Andreas}, title = {Fast response of Scots pine to improved water availability reflected in tree-ring width and δ13C}, series = {Plant, Cell and Environment}, volume = {33}, journal = {Plant, Cell and Environment}, number = {8}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1365-3040 (Online)}, doi = {10.1111/j.1365-3040.2010.02153.x}, pages = {1351 -- 1360}, year = {2010}, abstract = {Drought-induced forest decline, like the Scots pine mortality in inner-Alpine valleys, will gain in importance as the frequency and severity of drought events are expected to increase. To understand how chronic drought affects tree growth and tree-ring δ13C values, we studied mature Scots pine in an irrigation experiment in an inner-Alpine valley. Tree growth and isotope analyses were carried out at the annual and seasonal scale. At the seasonal scale, maximum δ13C values were measured after the hottest and driest period of the year, and were associated with decreasing growth rates. Inter-annual δ13C values in early- and latewood showed a strong correlation with annual climatic conditions and an immediate decrease as a response to irrigation. This indicates a tight coupling between wood formation and the freshly produced assimilates for trees exposed to chronic drought. This rapid appearance of the isotopic signal is a strong indication for an immediate and direct transfer of newly synthesized assimilates for biomass production. The fast appearance and the distinct isotopic signal suggest a low availability of old stored carbohydrates. If this was a sign for C-storage depletion, an increasing mortality could be expected when stressors increase the need for carbohydrate for defence, repair or regeneration.}, language = {en} } @article{FontivonArxGarciaGonzalezetal.2010, author = {Fonti, Patrick and von Arx, Georg and Garc{\´i}a-Gonz{\´a}lez, Ignacio and Eilmann, Britta and Sass-Klaassen, Ute G. W. and G{\"a}rtner, Holger and Eckstein, Dieter}, title = {Studying global change through investigation of the plastic responses of xylem anatomy in tree rings}, series = {New Phytologist}, volume = {185}, journal = {New Phytologist}, number = {1}, publisher = {Wiley-Blackwell}, address = {Oxford}, issn = {1469-8137 (Online)}, doi = {10.1111/j.1469-8137.2009.03030.x}, pages = {42 -- 53}, year = {2010}, abstract = {Variability in xylem anatomy is of interest to plant scientists because of the role water transport plays in plant performance and survival. Insights into plant adjustments to changing environmental conditions have mainly been obtained through structural and functional comparative studies between taxa or within taxa on contrasting sites or along environmental gradients. Yet, a gap exists regarding the study of hydraulic adjustments in response to environmental changes over the lifetimes of plants. In trees, dated tree-ring series are often exploited to reconstruct dynamics in ecological conditions, and recent work in which wood-anatomical variables have been used in dendrochronology has produced promising results. Environmental signals identified in water-conducting cells carry novel information reflecting changes in regional conditions and are mostly related to short, sub-annual intervals. Although the idea of investigating environmental signals through wood anatomical time series goes back to the 1960s, it is only recently that low-cost computerized image-analysis systems have enabled increased scientific output in this field. We believe that the study of tree-ring anatomy is emerging as a promising approach in tree biology and climate change research, particularly if complemented by physiological and ecological studies. This contribution presents the rationale, the potential, and the methodological challenges of this innovative approach.}, language = {en} } @misc{HezelFrauenrathRenzetal.2010, author = {Hezel, Fabian and Frauenrath, Tobias and Renz, Wolfgang and Schulz-Menger, Jeanette and Niendorf, Thoralf}, title = {Feasibility of CINE Myocardial T2* Mapping Using Susceptibility Weighted Gradient-Echo Imaging at 7.0 T}, series = {2010 ISMRM-ESMRMB joint annual meeting}, journal = {2010 ISMRM-ESMRMB joint annual meeting}, issn = {1545-4428}, year = {2010}, abstract = {This study is designed to demonstrate the promise of susceptibility weighted 2D CINE FLASH and T2* Mapping of the heart at 7T.}, language = {en} } @article{RiglingEilmannKoechlietal.2010, author = {Rigling, Andreas and Eilmann, Britta and Koechli, Roger and Dobbertin, Matthias}, title = {Mistletoe-induced crown degradation in Scots pine in a xeric environment}, volume = {30}, number = {7}, publisher = {Oxford University Press}, address = {Oxford}, issn = {1758-4469 (Online)}, doi = {10.1093/treephys/tpq038}, pages = {845 -- 832}, year = {2010}, abstract = {Increasing Scots pine (Pinus sylvestris L.) mortality has been recently observed in the dry inner valleys of the European Alps. Besides drought, infection with pine mistletoe (Viscum album ssp. austriacum) seems to play an important role in the mortality dynamics of Scots pines, but how mistletoes promote pine decline remains unclear. To verify whether pine mistletoe infection weakens the host via crown degradation, as observed for dwarf mistletoes, we studied the negative effects of pine mistletoe infestation on the photosynthetic tissues and branch growth of pairs of infested and non-infested branches. Pine mistletoe infection leads to crown degradation in its host by reducing the length, the radial increment, the ramification, the needle length and the number of needle years of the infested branches. This massive loss in photosynthetic tissue results in a reduction in primary production and a subsequent decrease in carbohydrate availability. The significant reduction in needle length due to mistletoe infection is an indication for a lower water and nutrient availability in infested branches. Thus, mistletoe infection might lead to a decrease in the availability of water and carbohydrates, the two most important growth factors, which are already shortened due to the chronic drought situation in the area. Therefore, pine mistletoe increases the risk of drought-induced mortality of its host when growing in a xeric environment.}, language = {en} } @article{RieplPettrakFaulstichetal.2010, author = {Riepl, Herbert Matthias and Pettrak, J{\"u}rgen and Faulstich, Martin and Herrmann, Wolfgang Anton}, title = {Self metathesis of fatty alcohols and amines to provide monomers for polyester and polyamide products}, series = {Macromolecular Symposia}, volume = {293}, journal = {Macromolecular Symposia}, number = {1}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1521-3900 (eISSN)}, doi = {10.1002/masy.200900041}, pages = {39 -- 42}, year = {2010}, abstract = {Self metathesis of oleochemicals offers a variety of bifunctional compounds, that can be used as monomer for polymer production. Many precursors are in huge scales available, like oleic acid ester (biodiesel), oleyl alcohol (tensides), oleyl amines (tensides, lubricants). We show several ways to produce and separate and purify C18-α,ω-bifunctional compounds, using Grubbs 2nd Generation catalysts, starting from technical grade educts.}, language = {en} } @article{FrauenrathHezelRenzetal.2010, author = {Frauenrath, Tobias and Hezel, Fabian and Renz, Wolfgang and de Geyer d'Orth, Thibaut and Dieringer, Matthias and von Knobelsdorf-Brenkenhoff, Florian and Prothmann, Marcel and Schulz-Menger, Jeanette and Niendorf, Thoralf}, title = {Acoustic cardiac triggering: a practical solution for synchronization and gating of cardiovascular magnetic resonance at 7 Tesla}, series = {Journal of Cardiovascular Magnetic Resonance}, volume = {12}, journal = {Journal of Cardiovascular Magnetic Resonance}, number = {1}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1532-429X}, doi = {10.1186/1532-429X-12-67}, year = {2010}, abstract = {Background To demonstrate the applicability of acoustic cardiac triggering (ACT) for imaging of the heart at ultrahigh magnetic fields (7.0 T) by comparing phonocardiogram, conventional vector electrocardiogram (ECG) and traditional pulse oximetry (POX) triggered 2D CINE acquisitions together with (i) a qualitative image quality analysis, (ii) an assessment of the left ventricular function parameter and (iii) an examination of trigger reliability and trigger detection variance derived from the signal waveforms. Results ECG was susceptible to severe distortions at 7.0 T. POX and ACT provided waveforms free of interferences from electromagnetic fields or from magneto-hydrodynamic effects. Frequent R-wave mis-registration occurred in ECG-triggered acquisitions with a failure rate of up to 30\% resulting in cardiac motion induced artifacts. ACT and POX triggering produced images free of cardiac motion artefacts. ECG showed a severe jitter in the R-wave detection. POX also showed a trigger jitter of approximately Δt = 72 ms which is equivalent to two cardiac phases. ACT showed a jitter of approximately Δt = 5 ms only. ECG waveforms revealed a standard deviation for the cardiac trigger offset larger than that observed for ACT or POX waveforms. Image quality assessment showed that ACT substantially improved image quality as compared to ECG (image quality score at end-diastole: ECG = 1.7 ± 0.5, ACT = 2.4 ± 0.5, p = 0.04) while the comparison between ECG vs. POX gated acquisitions showed no significant differences in image quality (image quality score: ECG = 1.7 ± 0.5, POX = 2.0 ± 0.5, p = 0.34). Conclusions The applicability of acoustic triggering for cardiac CINE imaging at 7.0 T was demonstrated. ACT's trigger reliability and fidelity are superior to that of ECG and POX. ACT promises to be beneficial for cardiovascular magnetic resonance at ultra-high field strengths including 7.0 T.}, language = {en} } @article{BarbazanHagenbachPaulssenetal.2010, author = {Barbaz{\´a}n, Paula and Hagenbach, Adelheid and Paulßen, Elisabeth and Abram, Ulrich and Carballo, Rosa and Rodriguez-Hermida, Sabina and V{\´a}zquez-L{\´o}pez, Ezequiel M.}, title = {Tricarbonyl Rhenium(I) and Technetium(I) Complexes with Hydrazones Derived from 4,5-Diazafluoren-9-one and 1,10-Phenanthroline-5,6-dione}, series = {European Journal of Inorganic Chemistry}, journal = {European Journal of Inorganic Chemistry}, number = {29}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1099-0682}, doi = {10.1002/ejic.201000522}, pages = {4622 -- 4630}, year = {2010}, abstract = {Tricarbonylrhenium(I) and -technetium(I) halide (halide = Cl and Br) complexes of ligands derived from 4,5-diazafluoren-9-one (df) and 1,10-phenanthroline-5,6-dione (phen) derivatives of benzoic and 2-hydroxybenzoic acid hydrazides have been prepared. The complexes have been characterized by elemental analysis, MS, IR, 1H NMR and absorption and emission UV/Vis spectroscopic methods. The metal centres (ReI and TcI) are coordinated through the nitrogen imine atoms and establish five-membered chelate rings, whereas the hydrazone groups stand uncoordinated. The 1H NMR spectra suggest the same behaviour in solution on the basis of only marginal variations in the chemical shifts of the hydrazine protons.}, 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} } @misc{Digel2010, author = {Digel, Ilya}, title = {In-situ biological decontamination of an ice melting probe}, year = {2010}, language = {en} }