Cette thèse vise à répondre à trois questions soulevées par la vague de réformes dans les secteurs de l’électricité: est-ce que la libéralisation de la fourniture d’électricité a atteint ses objectifs dans l’Union Européenne ? Comment les producteurs qui utilisent des sources renouvelables et non renouvelables se font concurrence dans le marché libéralisé ? Quel est l’'impact de l’augmentation de la production d’électricité à partir de sources renouvelables sur la congestion du réseau et sur les différences de prix zonaux en Italie ? Le premier chapitre fournit une évaluation à mi-terme de la libéralisation de la fourniture d’électricité en Europe. On propose une théorie complète sur la libéralisation de la fourniture et on teste sa cohérence avec la pratique dans l’Union Européenne. L’analyse met en évidence la persistance d’une structure oligopolistique dans la fourniture, un faible engagement des clients et des asymétries dans le taux et la vitesse de transfert des coûts d’approvisionnement dans les prix des contrats. L’attribution aux enchères des services par défaut et de dernier recours semble la meilleure solution afin de favoriser le développement de la concurrence. Dans le deuxième chapitre, nous étudions les interactions stratégiques entre une technologie de production traditionnelle et une renouvelable caractérisée par une capacité aléatoire. Nous employons une version modifiée du modèle de Dixit sur les investissements stratégiques de dissuasion à l’entrée avec deux configurations pour la concurrence après l’entrée: concurrence à la Cournot dans un jeu en deux étapes et le cadre entreprise dominante-frange concurrentielle dans un jeu en trois étapes. Dans les deux cas, l’analyse suggère que le producteur renouvelable exploite l’ordre de mérite afin de remplacer la production de son rival. Dans le troisième chapitre, nous analysons l’impact de la production d’énergie renouvelable sur la congestion et sur les différences de prix zonaux en Italie. En utilisant une base de données unique, nous estimons deux modèles économétriques sur cinq couples de zones: un modèle logit multinomial pour l’occurrence et la direction de la congestion et un modèle MCO pour la taille des différences de prix. L’analyse montre que dans une région importatrice l’effet de l’augmentation de la production renouvelable locale est de diminuer (augmenter) la probabilité de congestion provoquée par la région limitrophe (causée à la région limitrophe). L’augmentation de la production d’énergie renouvelable semble avoir un impact significatif sur les zones insulaires, en diminuant (augmentant) le niveau des différences positives (négatives) des prix. / The objective of this thesis is to answer to three questions raised by the wave of reform in electricity industries: has retail liberalization achieved its objectives in European Union? How traditional and renewable generators compete in a liberalized market? What is the impact on congestion and zonal price differences of increased production from renewable intermittent sources in Italy? The first chapter provides a mid-term evaluation of liberalization of electricity retailing in Europe. We propose a comprehensive theory on retail liberalization and test its consistency with the practice in European Union. The analysis highlights the presence of an oligopolistic supply structure, a limited level of customer engagement in the market and asymmetries in the rate and speed of cost-pass through. The attribution of the Default/Last Resort service through an auction mechanism seems the best solution to favor the development of competition. In the second chapter we study the strategic interactions between a traditional generation technology and a renewable one characterized by an intermittent availability of capacity. We employ a modified version of the Dixit model for entry deterrence with two post entry competition settings: the Cournot framework in a two stage game and the dominant firm-competitive fringe setting in a three stage game. In both cases, the analysis suggests that the renewable generator exploits the merit order rule to crowd out the production of its rival. In the third chapter we analyze the impact of renewable generation on congestion and zonal price differences in Italy. Using a unique database we estimate two econometric models on five zonal pairings: a multinomial logit model for the occurrence and direction of congestion and an OLS model for the size of paired-price differences. The analysis shows that in an importing region the effect of a larger local renewable supply is to decrease (increase) the probability of congestion in entry (exit). Increasing renewable generation seems to have a significant impact on the islander zones, decreasing (increasing) the level of positive (negative) price differences

The aim of this thesis is to describe the situation of a demographic ageing in the Czech Republic from perspective a reproduction of the workforce and the human capital. Most conclusions regarding a demographic ageing are based on a number of people in each generation. On the other side conclusions based on a human capital data are often ignored and marginalized.The main aim of this thesis is not to discover the unknow, but to describe and analyze demographic ageing in the Czech Republic. This thesis want to show that the demographic ageing is a serious topic that cannot be overlooked.

A soldagem a ponto por resistência é o processo de união de partes mais comum utilizado na indústria automobilística. Vários métodos de representação de pontos de solda estão disponíveis, e este trabalho se propõe comparar dois métodos de modelagem de pontos de solda através de um estudo de correlação, em termos da força máxima suportada pela junta soldada, entre os resultados de testes virtuais e de laboratório. Estes métodos de representação dos pontos de solda são os elementos de viga e os elementos sólidos. Os testes utilizados neste estudo de correlação carregam o corpo de provas sob ação de forças de cisalhamento e normal aplicadas diretamente no ponto de solda. E para completar este estudo de correlação, o entendimento dos modos e critérios de falha de juntas soldadas também é necessário. Os modelos de elementos finitos dos corpos de prova gerados para serem testados sob condições de cisalhamento e de força normal são detalhados pela apresentação dos tipos de materiais, elementos, formulações de contato e carregamento utilizados. Estes modelos foram analisados pelo LS-DYNA, que é um código de elementos finitos de propósito geral para análise de respostas dinâmicas provenientes de grandes deformações de estruturas. Da mesma forma, os testes físicos e os corpos de prova utilizados são detalhados, e os resultados provenientes dos testes são comparados aos obtidos nas simulações. Dos resultados obtidos, a melhor correlação se deu com a utilização do elemento sólido para representar o ponto de solda, com diferenças entre os resultados físicos e virtuais em torno de 4%. Uma representação simples do ponto de solda é indicada no caso de modelos completos e para aplicações na indústria, alguns fatores, tais como a modelagem da ZTA, podem ser suprimidos. Uma breve descrição do processo de soldagem a ponto, alguns tópicos da análise de elementos finitos não-linear e algumas características do LS-DYNA, além das conclusões e recomendações para trabalhos posteriores, completam este estudo. / Resistance spot welding is the most common jointing process of parts used in automotive industry. Several methods to represent spot welds are available, and the purpose of this work is to compare two different methods of spot weld modeling through a correlation study, taking into consideration the maximum force withstood by the welded joint, between virtual and lab test results. These spot weld representation methods are beam and solid elements. The tests used in this correlation study load the specimens under pure shear and pure normal forces. And in order to complete this correlation study, the understanding of the failure modes and criteria is also necessary. The specimens finite element models generated to be tested under purê shear and normal conditions are detailed by the presentation of materials, elements contact formulations and loading types used. These models were analyzed by the LS-DYNA, which is general purpose finite element code for analyzing the large deformation dynamic response of structures. As well, the physical tests and used specimens are detailed, and the results from the tests are compared to the results obtained in the simulations. Taking the obtained results, the best correlation was found using solid elements to represent the spot weld, due to differences between the physical and the virtual results about 4%. A simple representation of the spot weld is indicated in case of a complete model, and for the industry application, some factors such as the HAZ, may be suppressed. A brief description of the spot welding process, some topics of the non-liner finite element analysis and some features of the LS-DYNA, and also the conclusions and recommendations for future works, complete this study.

A crescente exigência do setor automotivo por maior produtividade com redução de custos, aliada aos novos materiais que compõe as carrocerias e seus revestimentos, levou ao estudo da correlação da resistência dinâmica, força de expansão térmica e indentação, com a formação do ponto de solda, a fim de qualificar e controlar a soldagem por resistência a ponto. Para o estudo ter validade prática a qualificação da solda, os parâmetros de soldagem e corpos de prova foram definidos conforme norma AWS-SAE D8-9M 2002. Os corpos de prova para os ensaios foram retirados das chapas que compõe uma carroceria veicular. O cabeçote de soldagem foi projetado e construído seguindo os padrões de máquinas industriais. Os instrumentos de medição foram desenvolvidos especificamente para atender as condições industriais da soldagem por resistência. Os ensaios simularam as variações de parâmetros e produção dos pontos de solda conforme ocorre na indústria automobilística. As análises foram realizadas através da comparação gráfica e matemática do comportamento das grandezas medidas com a qualificação dimensional do ponto. A correlação, apresentada, distingue chapas de espessuras diferentes, materiais de revestimento, variação de parâmetros, erros de posicionamento (ponto torto), expulsão de material (flash), variações na formação do ponto (undersize) e o mais importante, desgaste dos eletrodos. Esta correlação permite criar um sistema de qualificação e controle do ponto de solda. / The growing demand from the automotive sector for greater productivity, reduced costs, combined with new materials that make up their bodies and coats, led to the study of the correlation of the dynamic resistance, thermal force expansion and indentation, with the formation of the spot weld, in order to qualify and control the resistance spot welding. For the study to be valid practicing the qualification of spot weld, welding parameters and specimens were define according AWS - 9M SAE D8 2002 standard. The specimens for testing were removed from the sheets that make up a vehicle body. The welding head was designed and built according the standards of industrial machinery. Measuring instruments were developed specifically to meet the conditions of industrial resistance welding. The tests simulated the variations of parameters and production of welding spots as occurs in automotive industry. The analyzes were performed through the graphical comparison and mathematical behavior of measured quantities with dimensional spot qualification. The correlation presented distinguishes sheets of different thicknesses, coating materials, variation of parameters, positioning errors (crooked point), expulsion of material (flash), variations in spot formation (undersize) and most important, wear of the electrodes. This correlation allows to create a system of qualification and control of the spot welding.

O presente trabalho teve como objetivo desenvolver uma metodologia prática e confiável para previsão de vida à fadiga de juntas soldadas a cordão pelo processo MIG/MAG, quando estas estão submetidas a carregamentos cíclicos combinados. A máxima tensão linear no pé da solda, região típica de início de trinca, conhecida como hot spot foi utilizada para prever a vida através do método de Fadiga de Alto Ciclo S x N (Tensão x Vida), largamente empregado em códigos de projeto de estruturas soldadas. O Método dos Elementos Finitos foi utilizado para determinação das tensões estruturais resultantes do carregamento e das descontinuidades geométricas presentes nos cordões de solda. A análise de fadiga foi efetuada em ambiente virtual, através de um software (programa) de fadiga capaz de importar as tensões atuantes na região da solda para cada carregamento, combinando-as e obtendo assim a vida à fadiga decorrente da somatória dos diferentes tipos de carregamento ao qual a junta foi submetida. As propriedades monotônicas e cíclicas dos materiais da junta foram obtidas da literatura e de um extenso banco de dados disponível no software de fadiga. Estas propriedades foram ajustadas com base em ensaios de laboratório nas juntas investigadas. A medição ou modelagem das tensões residuais inerentes ao processo de soldagem não fazem parte do escopo deste trabalho. Contudo, os efeitos térmicos e metalúrgicos resultantes do processo de soldagem, como distorções, tensões residuais, variações microestruturais e propriedades mecânicas foram considerados de forma indireta, através da correção das curvas de fadiga nos corpos de prova investigados. Corpos de prova do tipo tubo-placa foram submetidos a carregamentos cíclicos combinados (flexão e torção) de amplitude constante. O resultado da análise virtual de durabilidade foi, portanto, calibrado com base nestes experimentos e curvas disponíveis em códigos de projeto de fadiga como BS7608 e Eurocode 3. A aplicabilidade deste método numérico-experimental e suas contribuições para a garantia da Integridade Estrutural do projeto de juntas soldadas são apresentadas. Seus desafios e melhorias são por fim discutidos. / The main purpose of this work is to develop a practical and robust methodology to evaluate the fatigue life in seam weld joints fabricated with GMAW process when subjected to combine cyclic loading. The maximum linear stress at the typical crack initiation region, better known as hot spot stress, was used to calculate the fatigue life through high cycle fatigue method S x N (Stress x Life), widely used in design codes for the life assessment of welded structures. The Finite Element Method (FEM) was used to obtain the structural stresses distribution due the external loading and geometric discontinuities very common in seam weld joints. The fatigue analysis was conducted in virtual environment. The FEM stress results from each loading were imported to fatigue code FE-Fatigue and combined to perform the fatigue life prediction. The monotonic and cyclic properties of the joint materials were obtained in the literature and from the fatigue software database. These properties were adjusted based on laboratory fatigue tests in the investigated welded joints configurations. The measurement or modeling of the residual stresses resulted from the welded process is not part of this work. However, the thermal and metallurgical effects, like distortions and residual stresses, were considered indirectly through fatigue curves corrections in the samples investigated. A tube-plate specimen was submitted to combine cyclic loading (bending and torsion) with constant amplitude. The virtual durability analysis result was calibrated based on these laboratory tests and design codes such as BS7608 and Eurocode 3. The feasibility and application of the proposed numerical-experimental methodology and contributions for the welded joints structural integrity design are presented. The challenges and improvements are finally discussed.

Spot welding of 1.4307 material of 1+1 mm thickness is tuned out excellently by the enterprise ROSTEX – at the changes only of the welding current it was managed to approach the value of thickness achieved by enterprise ROSTEX. At the welding of 1.4307 material of 2+2 mm thickness it was managed to achieve more strength under welding parameters: Fs = 5500N, Is = 8,964 kA, ts = 10 Per. Spot welding of 1.0330 material revealed a possibility in proceeding with welding current increasing which could stand for the weld strength increasing (not necessarily) – a limit where material could splash was not achieved. The soft mode welding is not convenient for up-to date spot welding because the material is extremely affected by heat at the long welding time, it also leads to huge thermal losses, thermal effect and distortion of electrodes (electrodes life diminishing). Soft mode welding is not expedient even economically. In accordance with economic comparison, see chart 27, page 64 – for instance welding of 1.4307 material with 1+1 mm thickness at 1000 welds there is difference of 644 Czech crowns between the hard and the soft mode welding in benefit to the hard mode.

This Master Thesis compares three various concrete materials for stiffening orthotropic bridge deck plate and investigates stress reducing factors in selected weld joints. The thesis investigates the standard load situation and also overloaded situation. A parameter study with different material inputs has been done to see how it affects stress in weld joints.

Voter decision-making about which political party to support in the elections is a very complex process. One of the key factors influencing our voting behaviour is the effect of particular candidates in terms of their local activities. Many Czech and also foreign studies show that candidates gain significantly higher preferences in the municipality of their residence and its surroundings. Within the analyzed parliamentary elections, this is reflected not only by the territorial concentration of preferential votes, but also by higher local electoral support of the political parties or movements represented by these candidates. This diploma thesis examines, among other things, differences in the strength of the described effect (technically called the friends and neighbours effect) between candidates from different political parties and in different regions of Czechia. Quantitative research has shown greater local strength and spatial extent of friends and neighbours effect for leading candidates from non-metropolitan areas who have experiences from local or regional politics, such as mayors or regional councilors. In the 2017 parliamentary elections, the friends and neighbours effect mostly influenced the spatial patterns of electoral support of the KDU-ČSL and the STAN movement and on the other...

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Ziel dieser Arbeit ist es eine Toolbox zur Charakterisierung der anomalen Diffusion von Tracerpartikeln in dicht gepackten Systemen mit Fluoreszenz-Korrelationsspektroskopie (FCS) zur Verfügung zu stellen. Es wird gezeigt, dass die robusten Informationen über die Wahrscheinlichkeitsdichtefunktion (PDF) der Verschiebung des Tracers im asymptotischen Verhalten der FCS-Kurven auf langen, sowie auf kurzen Zeitskalen enthalten sind. So liefert die Analyse des Kurzzeitverhaltens zuverlässige Aussagen über die Werte des Exponenten der anomalen Diffusion, des Diffusionskoeffizienten und der niedrigeren Momente der PDF. Dies erlaubt es eine Gaußverteilung zu bestätigen oder zu widerlegen. Der Test auf Gaußverteilung könnte als Index verwendet werden, um die richtige Form der PDF aus einer Reihe von konkurrierenden Ergebnissen zu erraten. Darüber hinaus untersuchen wir die Konsequenz der nicht skalierenden PDF auf Ergebnis der FCS-Kurven. Wir berechnen die FCS für ein Continuous Time Random Walk Modell mit Wartezeiten gemäß einer Lévy-stabilen Verteilung mit exponentiellem cut-off. Die Ergebnisse zeigen, dass obwohl die Abweichungen vom Gauß’schen Verhalten bei der asymptotischen Analyse erkannt werden können, ihre Körper immer an Formen für die normale Diffusion perfekt angepasst werden können. Schließlich schlagen wir einen alternativen Ansatz für die Durchführung von Spot Variation FCS mit dem gewöhnlichen FCS-Setup vor. Wir führen eine nicht-lineare Transformation ein, die auf das mit Binning oder Kernel smoothing method geglättete Intensitätsprofil der detektierten Fluoreszenzphotonen angewendet wird. Ihre Autokorrelation imitiert die FCS-Kurven für die Größen des Laserspots, die im Experiment effektiv kleiner als die anfängliche Größe sind. Die erhaltenen FCS-Kurven werden verwendet, um künstliche dicht gepackte Systeme sowie lebende Zellen auf Nano-Domänen oder Barrieren hin zu untersuchen. / The objective of this thesis is to provide a toolbox for characterization of anomalous diffusion of tracer particle in crowded systems using fluorescence correlation spectroscopy (FCS). We discuss that the robust information about the probability density function (PDF) of the particle’s displacement is contained in the asymptotic behaviour of the FCS curves at long and short times. Thus, analysis of the short-time behaviour provides reliable values of exponent of anomalous, diffusion coefficient and lower moments of the PDF. This allows one to to confirm or reject its Gaussian nature. The Gaussianity test could be then used to guess the correct form of the PDF from a set of competing models. We show the applicability of the proposed analysis protocol in artificially crowded systems and in living cell experiments. Furthermore, we investigate the consequence of non-scaling PDF on the possible results of the FCS data. As an example of such processes, we calculate the FCS curve for a continues time random walk model with waiting times delivered from Lévy-stable distribution with an exponential cut-off in equilibrium. The results indicate that, although the deviations from Gaussian behaviour may be detected when analyzing the short- and long-time asymptotic of the corresponding curves, their bodies are still perfectly fitted by the fit form used for normal diffusion. Finally, we propose an alternative approach for performing spot variation FCS using an ordinary FCS set-up. We introduce a non-linear transformation which applies on the smoothed intensity profile of the detected fluorescence photons with binning or smoothing kernel method. Autocorrelation of the generated intensity profiles mimic the FCS curves for the sizes of laser spots which are effectively smaller than the initial one in the experiment. The obtained FCS curves are used to investigate the presence of nano-domains or barriers in artificially crowded systems and in living cells.