GPU Accelerated Explicit Time Integration Methods for Electro-Quasistatic Fields

Electro-quasistatic field problems involving nonlinear materials are commonly discretized in space using finite elements. In this paper, it is proposed to solve the resulting system of ordinary differential equations by an explicit Runge-Kutta-Chebyshev time-integration scheme. This mitigates the need for Newton-Raphson iterations, as they are necessary within fully implicit time integration schemes. However, the electro-quasistatic system of ordinary differential equations has a Laplace-type mass matrix such that parts of the explicit time-integration scheme remain implicit. An iterative solver with constant preconditioner is shown to efficiently solve the resulting multiple right-hand side problem. This approach allows an efficient parallel implementation on a system featuring multiple graphic processing units.Comment: 4 pages, 5 figure

Optimization of Photonic Band Structures

In this work we study mathematical optimization problems that arise in the design of photonic crystals, whose band structures should exhibit specific properties. To this end we develop a mathematical model for time-harmonic wave propagation in three-dimensional, periodic media. We investigate the dependency of band structures on the medium structure and develop two types of optimization algorithms. The performance of these algorithms is demonstrated through several of numerical experiments

Optimisation algorithms for the charge dispatch of plug-in vehicles based on variable tariffs

Plug-in vehicles powered by renewable energies are a viable way to reduce local and total emissions and could also support a highly efficient grid operation. Indirect control by variable tariffs is one option to link charging or even discharging time with the grid load and the renewable energy production. Algorithms are required to develop tariffs and evaluate grid impacts of variable tariffs for electric vehicles (BEV) as well as to schedule the charging process optimisation. Therefore a combinatorial optimisation algorithm is developed and an algorithm based on graph search is used and customised. Both algorithms are explained and compared by performance and adequate applications. The developing approach and the correctness of the quick combinatorial algorithm are proved within this paper. For vehicle to grid (V2G) concepts, battery degradation costs have to be considered. Therefore, common life cycle assumptions based on the battery state of charge (SoC) have been used to include degradation costs for different Li-Ion batteries into the graph search algorithm. An application of these optimisation algorithms, like the onboard dispatcher, which is used in the German fleet test "Flottenversuch Elektromobiliät". Grid impact calculations based on the optimisation algorithm are shown. --BEV,V2G,Plug-In-Vehicles (PHEV),optimisation,mobile dispatcher,demand side management,charging,combinatorial algorithm,graph search algorithm,indirect control by variable tariffs

Non-local self energies in pyrochlore iridates from ab-initio TRILEX calculations, and their relevance for the Weyl semimetal phase

Motivated by recent experiments and computational results on pyrochlore iridates, we compare single-particle properties of Y2Ir2O7 obtained from single-site dynamical mean-field calculations with results within the TRILEX approximation, where the latter takes non-local correlations into account. Our calculations are all based on ab-initio calculations within density-functional theory, and take spin-orbit coupling into account. In order to make the treatment within TRILEX feasible, we first define a single-band jeff = 1/2 model, by comparing its spectral features within DMFT to a three-band model that includes both jeff = 1/2 and jeff = 3/2 orbitals. Our calculations show consistently a paramagnetic metallic phase at small interaction values, and an insulating antiferromagnetic phase at larger interaction values. The critical interactions, however, differ between single-site and TRILEX calculations. The antiferromagnetic phase shows the already predicted all-in/all-out magnetic ordering. Different to the single-site results, the TRILEX calculation gives also evidence for the Weyl-semimetal regime in the vicinity of the metal-insulator transition

Microdeflectometry - a novel tool to acquire 3D microtopography with nanometer height resolution

We introduce "microdeflectometry", a novel technique for measuring the microtopography of specular surfaces. The primary data is the local slope of the surface under test. Measuring the slope instead of the height implies high information efficiency and extreme sensitivity to local shape irregularities. The lateral resolution can be better than one micron whereas the resulting height resolution is in the range of one nanometer. Microdeflectometry can be supplemented by methods to expand the depth of field, with the potential to provide quantitative 3D imaging with SEM-like features.Comment: 3 pages, 11 figures, latex, zip-file, accepted for publication at Optics Letter

Branding excellence : Wegweiser für professionelles Markenmanagement

Marken zählen heute zu den wichtigsten Vermögenswerten von Unternehmen. Wie jedes andere Vermögen auch entstehen hohe Markenwerte jedoch nicht von ungefähr, sondern sind das Ergebnis von Arbeit, d.h. eines professionellen Markenmanagements. Allerdings hat sich diese elementare Erkenntnis in der Unternehmenspraxis bisher nicht auf breiter Front durchsetzen können. So wird Markenmanagement vielerorts noch immer als etwas „Magisches“ betrachtet, das man mehr oder weniger aus dem Bauch heraus betreiben kann. Doch Markenmanagement hat längst nichts mehr mit „Zauberei“ zu tun. Die Herausforderungen sind enorm: Steigende Produkt- und Markenvielfalt, anschwellende Kommunikationsflut sowie steigende Kosten der Markenführung sind nur einige Aspekte, die die Notwendigkeit für ein systematisches und professionelles Markenmanagement aufzeigen. Im vorliegenden Beitrag wird mit dem Branding-Excellence-Ansatz ein umfassender Orientierungsrahmen zur Systematisierung des Markenmanagements vorgestellt. Dieser ist zum einen als Instrument zur Bewertung der Professionalität des Markenmanagements von Unternehmen geeignet, zum anderen als eine Art Masterplan für Unternehmen mit potenziellen Marken zu sehen. Im Rahmen des Branding-Excellence-Ansatzes werden die zentralen Kennzeichen professionellen Markenmanagements deutlich. Die Professionalität des Markenmanagements schlägt sich dabei in vier Dimensionen nieder: in der Markenstrategie, im Markenauftritt, in der Markenerfolgsmessung und in der Markenverankerung im Unternehmen. Der vorliegende Beitrag stellt für jeden dieser vier Bereiche zentrale Konzepte und Instrumente vor. Darüber hinaus wird für jeden Themenbereich am Ende der Darstellung eine detaillierte Checkliste mit ausgewählten Branding-Excellence-Kriterien bereitgestellt, die zur Bewertung der Professionalität des Markenmanagements herangezogen werden kann

Flexibility of industrial product service systems: An assessment based on concept modelling

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Structure of 3,4-Dihydroxy-2-butanone 4-Phosphate Synthase from Methanococcus jannaschii in Complex with Divalent Metal Ions and the Substrate Ribulose 5-Phosphate: implications for the catalytic mechanism

Skeletal rearrangements of carbohydrates are crucial for many biosynthetic pathways. In riboflavin biosynthesis ribulose 5-phosphate is converted into 3,4-dihydroxy-2-butanone 4-phosphate while its C4 atom is released as formate in a sequence of metal-dependent reactions. Here, we present the crystal structure of Methanococcus jannaschii 3,4-dihydroxy-2-butanone 4-phosphate synthase in complex with the substrate ribulose 5-phosphate at a dimetal center presumably consisting of non-catalytic zinc and calcium ions at 1.7-Å resolution. The carbonyl group (O2) and two out of three free hydroxyl groups (OH3 and OH4) of the substrate are metal-coordinated. We correlate previous mutational studies on this enzyme with the present structural results. Residues of the first coordination sphere involved in metal binding are indispensable for catalytic activity. Only Glu-185 of the second coordination sphere cannot be replaced without complete loss of activity. It contacts the C3 hydrogen atom directly and probably initiates enediol formation in concert with both metal ions to start the reaction sequence. Mechanistic similarities to Rubisco acting on the similar substrate ribulose 1,5-diphosphate in carbon dioxide fixation as well as other carbohydrate (reducto-) isomerases are discussed

Mechanisms of the aftershocks of the Kern County, California, earthquake of 1952

Using directions of first motion of longitudinal waves recorded at near-by stations, the orientation of fault traces and the nature of fault motions have been deduced for fifty-seven earthquakes of the Kern County aftershock series. Unlike the main shock, the aftershocks exhibit considerable strike slip with left-hand strike slip dominating on and to the south of the White Wolf fault and right-hand strike slip and dip slip to the north of it. The two last-mentioned mechanisms represent a secondary strain release, beginning not earlier than thirty-seven hours after the main shock

Characterization and adsorption-based applications of nanoporous materials

The workshop program will focus on adsorption measurement techniques and methodologies for the assessment of adsorption properties and textural/structural characterization of novel nanoporous materials including zeolites, carbons, MOFs as well as materials consisting of hierarchically structured pore networks. A major point will be the correlation of textural properties, adsorption behavior, catalytic reaction pathways as well as transport properties with applications in gas and energy storage, separations and catalysis. Within this framework, the workshop will offer a platform for scientific discussions and for a knowledge transfer between various scientific areas where diffusion and transport properties of porous materials are of importance