Electrical power system is an essential technical system intended to power supply. The power drain is still increasing and it is possible to suppose rising trend in the future. Because of this fact there are installed new power sources into the system, so it is important to know manners and parameters of the electricity supply system as well as the new power sources which we are connecting to the grid. Due to these reasons, the electricity supply system is being simplified and described as the steady state operation with different numerical methods. To dimension a connection of the new power source to the grid, it has to be determined short-circuit conditions too.

The diploma thesis is focused on the analysis of parallel operation of Čebín and Sokolnice substations. Different variants of parallel operation are researched. A calculation of steady state by the iterative method is described in the theoretical part. The next part briefly mentions a short-circuit and dimensioning of conductors. The possibility of overloading of lines and transformers is discussed in the last chapter of the theoretical part. The current state of the situation is described in the practical part. Main goal of the practical part of the diploma thesis is to design a configuration capable to parallel operation. Also another configuration of supply of this area is designed. There must be no direct connection between Čebín and Sokolnice substations on 110kV level in this configuration. This configuration should eliminate a transit flow of power. Each configuration has to fulfill the requirements on the steady state and on short-circuit current capability. One of the last chapters is focused on the steps, that should by undertaken to prevent transit flow of power.

Die Interaktion zwischen merkmalsbasierten und objektbasierten visuellen Aufmerksamkeitsprozessen stand im Fokus der vorliegenden Dissertation. Hierbei war insbesondere die Frage wesentlich, ob Objektmerkmale um visuelle Verarbeitungsressourcen konkurrieren. Zu diesem Zweck wurde in drei Experimenten mittels Elektroenzephalographie die neuronale Verarbeitung aufgabenrelevanter und aufgabenirrelevanter Objektmerkmale untersucht. Im ersten Experiment konnte gezeigt werden, dass das aufgabenrelevante Objektmerkmal einen Verarbeitungsvorteil aufweist. Darüber hinaus zeigte sich, dass sich dieser Verarbeitungsvorteil reduziert, wenn zwei Objektmerkmale beachtet werden müssen. Diese Ergebnisse stehen im Widerspruch zu Vorhersagen der Theorie des integrierenden Objekts und legen Wettbewerb zwischen den Objektmerkmalen nahe. Im zweiten Experiment zeigten sich durch den Austausch eines der Objektmerkmale überraschenderweise abweichende Effekte. Dennoch offenbarten sich auch hier Hinweise hinsichtlich der Existenz eines Wettbewerbs zwischen den Objektmerkmalen, der jedoch – neben der top-down Verzerrung durch merkmalsselektive Aufmerksamkeitsprozesse – bottom-up durch die Salienz des Objektmerkmals Luminanz verzerrt wurde. Im dritten Experiment, das sich der Analyse der Zeitverläufe merkmalsselektiver Aufmerksamkeitsprozesse innerhalb von Objekten widmete, konnte ein zweiphasiger Prozess demonstriert werden: Einer frühen transienten Integration aller Objektmerkmale folgen anhaltende merkmalsspezifische Mechanismen. Der Wettbewerb von Objektmerkmalen um visuelle Verarbeitungsressourcen ist demnach zeitabhängig. Dieser Befund ermöglicht die Synthese scheinbar widersprüchlicher Ergebnisse früherer Studien, die entweder in Experimenten mit kurzen Präsentationszeiten visueller Stimuli Merkmalsintegration innerhalb von Objekten zeigten (analog zur Theorie des integrierenden Objekts), oder aber durch Verwendung längerer Präsentationszeiten die merkmalsspezifische Verarbeitung von Objektmerkmalen demonstrieren konnten.

Das maximale Laktat-Steady-State (MLSS) ist die Belastungsintensität bei der sich gerade noch ein Fließgleichgewicht von Laktatbildung und -elimination einstellt. Dazu gibt es in der Literatur zahlreiche Messverfahren, denen eine Bestimmung der Laktatkonzentration im Blut zugrunde liegt. Den meisten dieser Verfahren fehlt allerdings eine biologisch-theoretische Grundlage. Aus diesem Grund haben Mader und Heck bereits Mitte der 80er Jahre ein mathematisches Modell erarbeitet, welches das Zustandekommen des MLSS unter steady-state Bedingungen auf theoretischer Basis erklärt. Dieses steady-state Modell beruht primär auf der Kenntnis der maximalen Sauerstoffaufnahme sowie der maximalen Laktatbildungsrate als Parameter der maximalen Leistungsfähigkeit der Atmung und der Glykolyse. Mit diesem theoretischen Modell zur Beschreibung der Funktion des Energiestoffwechsels unter Belastung können Trainingseffekte erklärt und Unterschiede zwischen Sportlern verstanden werden. Trotzdem wurden die durch Mader und Mitarbeiter angestellten theoretischen Überlegungen zum Verhalten des Energiestoffwechsels bisher nur zum Teil in der Praxis validiert und fanden bislang keinen breiten Eingang in sportmedizinischen Untersuchungen. Die vorliegende kumulativ angefertigte Arbeit umfasst daher vier Veröffentlichungen: Den Vergleich verschiedener Laktat-Schwellenkonzepte mit dem experimentell bestimmten MLSS, den Vergleich des theoretischen Modells des Energiestoffwechsels mit dem experimentell bestimmten MLSS, die Bestimmung der Reliabilität des theoretischen Modells des Energiestoffwechsels und die Untersuchung des Effektes einer Sprint- und Ausdauerbelastung auf die maximale Laktatbildungsrate, die maximale Sauerstoffaufnahme sowie das berechnete MLSS.

Many biological populations reside in increasingly fragmented landscapes, which arise from human activities and natural causes. Landscape characteristics may change abruptly in space and create sharp transitions (interfaces) in landscape quality. How patchy landscape affects ecosystem diversity and stability depends, among other things, on how individuals move through the landscape. Individuals adjust their movement behaviour to local habitat quality and show preferences for some habitat types over others. In this dissertation, we focus on how landscape composition and the movement behaviour at an interface between habitat patches of different quality affects the steady states of a single species and a predator-prey system. First, we consider a model for population dynamics in a habitat consisting of two homogeneous one-dimensional patches in a coupled ecological reaction-diffusion equation. Several recent publications by other authors explored how individual movement behaviour affects population-level dynamics in a framework of reaction-diffusion systems that are coupled through discontinuous boundary conditions. The movement between patches is incorporated into the interface conditions. While most of those works are based on linear analysis, we study positive steady states of the nonlinear equations. We establish the existence, uniqueness and global asymptotic stability of the steady state, and we classify their qualitative shape depending on movement behaviour. We clarify the role of nonrandom movement in this context, and we apply our analysis to a previous result where it was shown that a randomly diffusing population in a continuously varying habitat can exceed the carrying capacity at steady state. In particular, we apply our results to study the question of why and under which conditions the total population abundance at steady state may exceed the total carrying capacity of the landscape. Secondly, we model population dynamics with a predator-prey system in a coupled ecological reaction-diffusion equation in a heterogeneous landscape to study Turing patterns that emerge from diffusion-driven instability (DDI). We derive the DDI conditions, which consist of necessary and sufficient conditions for initiation of spatial patterns in a one-dimensional homogeneous landscape. We use a finite difference scheme method to numerically explore the general conditions using the May model, and we present numerical simulations to illustrate our results. Then we extend our studies on Turing-pattern formation by considering a predator-prey system on an infinite patchy periodic landscape. The movement between patches is incorporated into the interface conditions that link the reaction-diffusion equations between patches. We use a homogenization technique to obtain an analytically tractable approximate model and determine Turing-pattern formation conditions. We use numerical simulations to present our results from this approximation method for this model. With this tool, we then explore how differential movement and habitat preference of both species in this model (prey and predator) affect DDI.

This dissertation is focused on experimental study of lubricant film behavior under transient conditions. For real machine parts such as gears, roller bearings and cam mechanism the operating conditions such as speed, load and radius of curvature of rubbing surfaces are vary during the working cycle. Change in operating conditions may pose an increased risk of the lubricating film breakdown. Direct contact of rubbing surfaces at the time of the lubricating film breakdown causes an increase in friction and wear. The high-speed CMOS camera was used to record the dynamic changes in lubricating film thickness during the experiment. The optical interferometry method has been used for reverse reconstruction of lubricating film thickness of the recorded interferograms. It was confirmed that the operating parameters have a major impact on the formation of lubricant film and its thickness and a certain combination of boundary conditions can cause lubricating film rupture. The obtained results showed, that modified topography of the rubbing surfaces can help to increase the lubrication film thickness especially in critical phases of working cycle.

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19781号 / 農博第2177号 / 新制||農||1041(附属図書館) / 学位論文||H28||N4997(農学部図書室) / 32817 / 京都大学大学院農学研究科農学専攻 / (主査)教授 白岩 立彦, 教授 奥本 裕, 教授 稲村 達也 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

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This thesis has two major goals; first to develop scalable scripts for steady-state analysis, then to perform a case study on the dynamic properties of a vertical pile. The scripts are based on the numerical library PETSc for parallel linear algebra. This opens up the opportunity to use the scripts to solve large-scale models on supercomputers. The performance of the scripts are verified against problems with analytical solutions and the commercial software ABAQUS. The case study compares the numerical results with those obtained from an approximate solution.   The results from this thesis are verified scripts that can find a steady-state solution for linear-elastic isotropic solids on supercomputers. The case study has shown differences between numerical and semi-analytical solutions for a vertical pile. The dynamic stiffness show differences within reasonable limits but the equivalent viscous damping show larger differences. This is believed to come from the material damping in the soil that has been excluded from the approximate solution.   These two results make it possible for further case studies on typical three-dimensional problems, that result in large-scale models, such as the dynamic properties of a slanted pile or pile-groups. The scripts can easily be expanded and used for other interesting research projects and this is the major outcome of from this thesis.