Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A presente dissertaÃÃo de mestrado trata do desenvolvimento teÃrico-experimental de um novo modelo da Turbina Tesla, tambÃm conhecida como turbina de discos, em que o foco da pesquisa foi estudar esse dispositivo de propulsÃo visando sua aplicaÃÃo em sistemas de geraÃÃo de energia distribuÃda a partir de fontes renovÃveis de biomassa. Um protÃtipo da turbina foi desenvolvido, em escala de laboratÃrio, para determinar os parÃmetros de projeto atravÃs de estudos teÃrico e experimental, a fim de interpretar os fenÃmenos presentes nos processos internos desse tipo de mÃquina de fluxo. A pesquisa foi direcionada à anÃlise dos efeitos do espaÃamento entre discos sobre o torque e a potÃncia, como uma funÃÃo da camada limite fluidodinÃmica do escoamento, correlacionando os regimes de velocidades de escoamento Ãs propriedades do fluido de trabalho. A metodologia para cÃlculo das eficiÃncias isentrÃpicas e exergÃticas à estabelecida a partir de dados experimentais e da anÃlise teÃrica por simulaÃÃo (apoiada pelo software ANSYS-CFX), a qual determina o perfil de distribuiÃÃo de pressÃo dentro da cÃmara de expansÃo, caracterizando as linhas de escoamento e os gradientes de pressÃo. Complementarmente, uma anÃlise modal dos sinais de vibraÃÃo da turbina foi realizada, estudando o comportamento dinÃmico da estrutura com o propÃsito de detectar as freqÃÃncias naturais e investigando a influÃncia do espaÃamento dos discos sobre o nÃvel de vibraÃÃodesse dispositivo. Este estudo aponta a robustez e a versatilidade operacional desse tipo de turbina, pelo fato dela admitir ampla faixa de rotaÃÃo e por sua fÃcil adaptaÃÃo a geradores comerciais, sugerindo sua aplicaÃÃo em sistemas de geraÃÃo e co-geraÃÃo tanto para o meio rural como para a indÃstria. / The current masterâs dissertation treats the experimental and theoretical development of a new model of Tesla turbine, also known as disk turbine, in which the research focus was to study this propulsion device viewing its application in distributed energy generation systems from biomass renewable resources. A turbineâs prototype was developed, in laboratory scale, to determine the design parameters through the theoretical and experimental studies in order to interpret the phenomena present in the internal processes of this kind of flux machine. The research was directed toward the effect analysis of the gap between disks on the torque and the power, as a function of the flowâs fluidynamic boundary layer, correlating the flow velocity regimes with the working fluid properties. A methodology for isentropic and exergetic efficiency calculation is taken from experimental data and theoretical analyses through simulation (supported by the software ANSYS-CFX), which determines the pressure distribution profile inside the expansion chamber, characterizing flow lines and pressure gradients. Complementarily, a modal analysis of turbineâs vibration signals is performed, studying the dynamic behavior of the structure with the purposes of detecting the natural frequencies and investigating the influence of the diskâs gap on the vibration level of this device. This study points out the robustness and the operational versatility of this kind of turbine by the fact of it allows a wide rotation range and by its easy adaptation to commercial generators, suggesting its application into generation and co-generation systems for the rural area as well as for the industry.

Orientador: Rogério Custodio / Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química / Made available in DSpace on 2018-08-21T05:01:18Z (GMT). No. of bitstreams: 1 Streit_Livia_D.pdf: 1852639 bytes, checksum: 1d6bd6190d21b329d992dfe5f74f8993 (MD5) Previous issue date: 2012 / Resumo: O estudo de processos fotoeletrônicos, como energias de dupla ionização é de grante interesse teórico e experimental na área da física molecular. Cálculos e medidas experimentais de energias de dupla ionização e de energias de ligação de elétron envolvem o entendimento de correlação e relaxação eletrônica. A consideração de tais efeitos é indispensável para a obtenção de resultados precisos. No presente trabalho, tais processos fotoeletrônicos são estudados com métodos Pós-Hartree-Fock e Monte Carlo Quântico (MCQ). No último caso, o método foi adaptado de maneira a utilizar um tipo diferente de função de onda. A primeira parte desta tese envolve o estudo de energias de dupla ionização. O objetivo prinicipal é a análise do tipo de função de onda tentativa no método MCQ. Três diferentes formas foram estudadas: Uma função Hartree-Fock monodeterminante com uma função de correlação eletrônica explícita de Boys-Handy otimizada para a molécula; uma função CI multideterminante; e ainda, uma função de onda multideterminante construída a partir de orbitais de Dyson. Para obter a função de onda de Dyson, um extenso trabalho envolvendo estudo e programação do programa de cálculo de estrutura eletrônica Gaussian 09 foi necessário. A primeira parte da tese ainda envolve o estudo de energias de dupla ionização por métodos Interação de Configurações Multireferência MRCI e Gaussian-3 G3. Os resultados obtidos são comparados aos resultados obtidos por MCQ. A segunda parte da tese compreende o estudo de energias de ligação de elétron de complexos de gases nobres com o ânion Uracila. A coexistência de ânions em que o orbital singularmente ocupado apresenta características de um orbital de valência e de um orbital muito difuso é investigada através de análise de geometria e do cálculo de energias de afinidade eletrônica e de ligação de elétron dos complexos neutros e aniônicos / Abstract: The study of photoelectron processes such as double ionization energies has become a very interesting field in experimental and theoretical molecular physics. Calculation and experimental measure of double ionization energies and electron binding energies involve understanding of electron correlation and relaxation energies. Consideration of those effects are a requisite in order to predict precise values. In this work, those photoelectron processes are studied with post-Hartree-Fock and Quantum Monte Carlo (QMC) methods. In the latter case, the method was also modified to take in account a different type of wavefunction. The first part of this thesis is concerned with the study of double ionization energies. The main objective of this work is the analysis of the type of trial wavefunction in QMC method. Three different forms were studied: A single determinant Hartree-Fock function, with the Boys-Handy explicit electron correlation function optimized for the molecule; a multi-determinant CI wavefunction; and finally, a multi-determinant wavefunction built from Dyson orbitals. In order to obtain the Dyson wavefunction, an extensive work on studying and programming the electron structure package Gaussian 09 was necessary. The first part still comprises the study of double ionization energies with MRCI and G3 methods. The results thus obtained were compared to the QMC results. The second part of this thesis embraces the study of electron binding energies of uracil¿noble-gas complexes. The coexistence of valence and diffuse¿bound anions of U(Xe), suggested by experimental studies is investigated with geometry analysis and calculation of adiabatic electron affinities and vertical electron detachment energies of the neutral an anionic complexes / Doutorado / Físico-Química / Doutor em Ciências

Le risque est une propriété inhérente de chaque projet. En effet, tout projet est soumis, durant l’ensemble de son cycle de vie, à de nombreux risques qui sont d’origine interne et externe dont la maîtrise est un enjeu crucial pour la réussite du projet. Beaucoup d'outils de gestion des risques ont été développés, mais ont la faiblesse récurrente de ne représenter que le projet et traitent le risque de façon isolée. Les risques affectant le projet et étant générés par ce dernier, il est nécessaire de prendre en compte les nombreuses et complexes interactions entre projet, environnement et risques.Les travaux réalisés visent à mettre en place une méthode de gestion des risques inhérents aux projets en général et plus particulièrement aux projets du domaine compétitif des énergies renouvelables.Cette méthode s’appuie sur un cadre formel et des outils applicatifs permettant d’optimiser le management des risques liés au projet. En effet, un cadre de modélisation servant de support à la méthode et ayant pour but de faciliter la modélisation du projet en tant que système complexe a été déterminé. De plus, la représentation des interactions inhérentes au projet et la prise de décision ont été rendues possibles par la nature des attributs caractérisant les entités du projet et de son environnement, et les différents modèles d’évaluation, d’interprétation et de choix des alternatives. Cette méthode a été adaptée à la prise en compte des incertitudes inhérentes au projet et à son environnement. Pour cela, nous avons d’abord procédé à l’identification et à la description des incertitudes via la réalisation d’une base de connaissances relatives aux facteurs de risques et à la documentation des variables incertaines. Les incertitudes ont ensuite été formalisées, propagée et évaluées. / Risk is an inherent property of each project. Indeed, any project faces, throughout its whole life cycle, numerous risks. Those risks can have an internal or an external origin. Be able to control risks is a crucial stake for the project success. Many risk management tools have been developed, but have the recurring weakness of representing only the project and treating the risk in isolation. Risks affect the project and are generated by the project itself. So, it is necessary to consider the numerous and complex interactions between project, environment and risks.The work carried out aims to develop a risk management method suitable for all types of projects and more particularly for projects of the competitive field of renewable energies.This method relies on a formal framework, as well as on application tools to optimize project risk management. Indeed, a modeling framework which supports the method and aims to facilitate the modeling of the project as a complex system has been developed. Moreover, the representation of the interactions and the decision making have been allowed by the nature of the attributes characterizing the entities of the project and its environment and the different models for evaluation, interpretation and selection of alternatives. This method was adapted to the uncertain context. For this purpose, uncertainties have been identified and described via the realization of a data base on risk factors. Then, uncertainties have been formalized, propagated and evaluated.

La demande d'énergie consommée par les habitants a connu une croissance significative au cours des 30 dernières années. Par conséquent, des actions sont menées en vue de développement des énergies renouvelables et en particulier de l'énergie solaire. De nombreuses solutions technologiques ont ensuite été proposées, telles que les capteurs solaires PV/T dont l'objectif est d'améliorer la performance des panneaux PV en récupérant l’énergie thermique qu’ils dissipent à l’aide d’un fluide caloporteur. Les recherches en vue de l'amélioration des productivités thermiques et électriques de ces composants ont conduit à l'intégration progressive à l’enveloppe des bâtiments afin d'améliorer leur surface de captation d’énergie solaire. Face à la problématique énergétique, les solutions envisagées dans le domaine du bâtiment s’orientent sur un mix énergétique favorisant la production locale ainsi que l’autoconsommation. Concernant l’électricité, les systèmes photovoltaïques intégrés au bâtiment (BIPV) représentent l’une des rares technologies capables de produire de l’électricité localement et sans émettre de gaz à effet de serre. Cependant, le niveau de température auquel fonctionnent ces composants et en particulier les composants cristallins, influence sensiblement leur efficacité ainsi que leur durée de vie. Ceci est donc d’autant plus vrai en configuration d’intégration. Ces deux constats mettent en lumière l’importance du refroidissement passif par convection naturelle de ces modules. Ce travail porte sur la simulation numérique d'une façade PV partiellement transparente et ventilée, conçu pour le rafraichissement en été (par convection naturelle) et pour la récupération de chaleur en hiver (par ventilation mécanique). Pour les deux configurations, l'air dans la cavité est chauffé par la transmission du rayonnement solaire à travers des surfaces vitrées, et par les échanges convectif et radiatif. Le système est simulé à l'aide d'un modèle multi-physique réduit adapté à une grande échelle dans des conditions réelles d'exploitation et développé pour l'environnement logiciel TRNSYS. La validation du modèle est ensuite présentée en utilisant des données expérimentales du projet RESSOURCES (ANR-PREBAT 2007). Cette étape a conduit, dans le troisième chapitre du calcul des besoins de chauffage et de refroidissement d'un bâtiment et l'évaluation de l'impact des variations climatiques sur les performances du système. Les résultats ont permis enfin d'effectuer une analyse énergétique et exergo-économique. / The demand of energy consumed by human kind has been growing significantly over the past 30 years. Therefore, various actions are taken for the development of renewable energy and in particular solar energy. Many technological solutions have then been proposed, such as solar PV/T collectors whose objective is to improve the PV panels performance by recovering the heat lost with a heat removal fluid. The research for the improvement of the thermal and electrical productivities of these components has led to the gradual integration of the solar components into building in order to improve their absorbing area. Among technologies capable to produce electricity locally without con-tributing to greenhouse gas (GHG) releases is building integrated PV systems (BIPV). However, when exposed to intense solar radiation, the temperature of PV modules increases significantly, leading to a reduction in efficiency so that only about 14% of the incident radiation is converted into electrical energy. The high temperature also decreases the life of the modules, thereby making passive cooling of the PV components through natural convection a desirable and cost-effective means of overcoming both difficulties. A numerical model of heat transfer and fluid flow characteristics of natural convection of air is therefore undertaken so as to provide reliable information for the design of BIPV. A simplified numerical model is used to model the PVT collector so as to gain an understanding of the complex processes involved in cooling of integrated photovoltaic arrays in double-skin building surfaces. This work addresses the numerical simulation of a semi-transparent, ventilated PV façade designed for cooling in summer (by natural convection) and for heat recovery in winter (by mechanical ventilation). For both configurations, air in the cavity between the two building skins (photovoltaic façade and the primary building wall) is heated by transmission through transparent glazed sections, and by convective and radiative exchange. The system is simulated with the aid of a reduced-order multi-physics model adapted to a full scale arrangement operating under real conditions and developed for the TRNSYS software environment. Validation of the model and the subsequent simulation of a building-coupled system are then presented, which were undertaken using experimental data from the RESSOURCES project (ANR-PREBAT 2007). This step led, in the third chapter to the calculation of the heating and cooling needs of a simulated building and the investigation of impact of climatic variations on the system performance. The results have permitted finally to perform the exergy and exergoeconomic analysis.

No description available.

No description available.

No description available.

High Energy Stereoscopic System (H.E.S.S.) est un réseau de cinq télescopes à imagerie Cherenkov atmosphérique, localisé dans l’hémisphère sud, ayant pour but principal l’étude de rayons cosmiques couvrant une gamme d’énergie de 30 GeV à plusieurs dizaines de TeV. La technique de détection Cerenkov ainsi que les spécificités de la méthode de reconstruction employée par H.E.S.S. I (première phase de l’expérience H.E.S.S.), sont décrites dans cette thèse. Après plus de dix ans d’activité, l’expérience H.E.S.S. a enregistré une quantité de données importante. En plus des régions d’intérêts sondées par ces détecteurs, où des sources astrophysiques ont déjà été dévoilées, l’étude d’événements collectés permet d’améliorer la compréhension de leur environnement sous-jacent. En effet, des émissions diffuses encore non-comprises se superposent aux rayonnements provenant de sources actives. Elles sont pourtant d’un intérêt significatif en astrophysique, physique des particules, cosmologie et même dans certains domaines de physique au-delà des modèles standards, tel que la recherche de matière noire. Les émissions diffuses et leurs précédentes études sont présentées dans cette thèse, ainsi que leurs possibles origines, depuis les mécanismes d’accélération de rayons cosmiques jusqu’à la production de rayon gamma dans les sources actives ou encore par des processus secondaires impliquant les interactions de rayons cosmiques avec le milieu interstellaire. Dans ce travail, des outils pour étudier les émissions diffuses ont été développés. L’approche choisie permet de distinguer les différentes composantes dans les données étudiées et extraire une estimation de leur poids dans le spectre. Elle prend en compte deux aspects, expliqués séparément dans cette thèse. Dans un premier temps, la morphologie de la source active présente dans le champ de vue est utilisée pour la modéliser et obtenir son spectre. Ensuite, pour distinguer les différentes contributions du fond, la méthode se base sur des fonctions de densité de probabilité construites à partir de variables discriminantes. L’étude et manipulation préliminaires nécessaires des variables discriminantes sont également détaillées. Des sources astrophysiques connues sont utilisées comme référence pour l’analyse. Les spectres résultants pour la source active, les électrons et hadrons diffus sont présentés et discutés, ainsi qu’une limite supérieure sur le flux de l’émission diffuse gamma extragalactique. Les erreurs systématiques associées ont été estimées. Une technique de "unfolding" a été mise en place et utilisée pour vérifier les résultats pour les émissions diffuses. / The High Energy Stereoscopic System (H.E.S.S.) is an array of five Imaging Atmospheric \v{C}erenkov Telescopes (IACT) located in the Southern Hemisphere, whose primary goal is the study of cosmic gamma-rays in the 30 GeV - few tens of TeV energy range. The detection technique used by IACT as well as the specificities of the reconstruction method of H.E.S.S. I (first phase of the H.E.S.S. experiment) are fully described in this thesis. After more than ten years of activity the H.E.S.S. experiment has registered a large amount of data. In addition to the regions of interest that its detectors probe and where astrophysical sources were unveiled, many events collected provide useful information on their surrounding environment. Indeed, acting as a background to the active sources, one can find the diffuse emissions, which are not well understood and yet are of significant interest for astrophysics, particle physics, cosmology and even physics beyond standard models, such as the search for dark matter. The diffuse emissions and their previous studies are presented in this thesis, as well as their possible origin, starting from the acceleration of cosmic-rays mechanism and the gamma-ray production in the active sources or from secondary process involving cosmic-rays interactions in the interstellar medium.In this work, tools to investigate the diffuse emissions were developed. The approach aims at disentangling the different components of the studied data so as to extract an estimation of their weight in the spectrum. It takes into account two aspects, explained separately in this thesis. On the one hand, the morphology of the active source in the studied field of view is used to modelize it and obtain its spectrum. Then, to disentangle the different contributions in the background, the method is based on probability density functions (PDF) built with discriminant variables. The necessary preliminary study and manipulation of the discriminant variables is also detailed. Well known astrophysical sources are used as benchmarks for the analysis. The resulting spectra for the active source, diffuse electrons and hadrons are presented and discussed, in addition to an upper limit on the extragalactic diffuse gamma-ray emission flux. The associated systematic errors were estimated.

Philosophiae Doctor - PhD / In the first experiment high spin states in 194Tl, excited through the 181Ta (18O, 5n) heavyion fusion evaporation reaction were studied using the AFRODITE array at iThemba LABS. The γ-γ coincidences, RAD ratios and linear polarization measurements were carried out and the previously known level scheme of 194Tl was significantly extended. A total of five rotational bands four of which are new were observed. A pair of rotational bands associated with the πh9/2 ⊗ νi−1 13/2 configuration at lower spins and with the πh9/2 ⊗ νi−3 13/2 configuration at higher spins was found and interpreted as the first possible chiral bands followed above the band crossing. The two 4-quasiparticle bands show exceptionally close near-degeneracy in the excitation energies. Furthermore close similarity is also found in their alignments and B(M1)/B(E2) reduced transition probability ratios. In the second experiment lifetimes in 194Tl were measured using the DSAM technique with the excited states in this nucleus populated through the 181Ta (18O, 5n) reaction. A total of 25 lifetimes and 30 reduced transition probabilities of magnetic dipole B(M1) and electric quadrupole B(E2) have been evaluated. Furthermore B(M1) and B(E2) reduced transition probabilities in Bands 1 and 4, which have been regarded as chiral candidates, were found to be close to each other and reveals strong splitting along spin values. This further supports the proposed chiral nature of these two bands.

Cette thèse présente les trois approches : analytique, expérimentale et numérique développées pour étudier le comportement d'une hydrolienne à membrane ondulante. Cette technologie, portée par l'entreprise EEL Energy, est basée sur les déformations périodiques d'une structure flexible pré-contrainte. Des convertisseurs d'énergie, positionnés de part et d'autre du système, sont actionnés par le mouvement d'ondulation.Analytiquement, la membrane est représentée par un modèle linéaire de poutre à une dimension et l'écoulement par un fluide potentiel 3D. L'action du fluide sur la membrane est évaluée par la théorie des corps élancés. L'énergie est dissipée de façon continue sur la longueur de la membrane. Expérimentalement, un prototype à l'échelle 1/20ième a été développé, des micro-vérins permettent de simuler l'énergie produite. Les essais avec le prototype1/20ième ont permis de valider le concept d'hydrolienne à membrane ondulante et le mode de récupération d'énergie. Un modèle numérique 2D éléments finis a été mis au point. Chaque élément constitutif de la membrane y est reproduit, la dissipation d'énergie est réalisée par des éléments dissipatifs mais la loi d'amortissement est limitée à un amortissement linéaire en vitesse.La comparaison des résultats issus de ces trois modèles a permis de valider leur bonne capacité à reproduire le comportement de la membrane sans conversion d'énergie. La dissipation d'énergie appliquée avec le modèle analytique se distingue clairement des deux autres modèles de part sa localisation mais aussi par la loi d'amortissement utilisée. Les autres modèles sont cohérents entre eux et si on ne parvient pas à corréler les résultats de puissance dissipée, le comportement du système et la répartition de la puissance dissipée le long de la membrane sont semblables. Ces trois approches ont permis de mettre en avant les paramètres clés dont dépend le comportement de la membrane et l'étude paramétrique démontre la complémentarité et l'intérêt du développement conjoint des modèles dans un souci industriel d'optimisation du système. Le développement d'un prototype à l'échelle supérieure (1/6ème), devant faire le lien entre les essais en bassin et les essais en mer, a permis de travailler sur les effets d'échelle. Des différences de comportements sont observées entre ces deux prototypes mais elles sont dues en partie à des différences de conditions aux limites et en partie à des effets de confinements très importants. Pour évaluer la tenue sur le long terme du prototype, ses composants (composite, élastomère) ont été caractérisés précisément et des essais de vieillissement accéléré par température ainsi que des essais de fatigue ont été mis en place sur des échantillons de matière. / This manuscript presents three approaches : analytical, experimental and numerical, to study the behavior of a flexible membrane tidal energy convertor. This technology, developed by the EEL Energy company, is based on periodic deformations of a pre-stressed flexible structure. Energy convertors, located on each side of the device, are set into motion by the wave-like motion.In the analytical model, the membrane is represented by a linear beam model at one dimension and the flow by a 3 dimensions potential fluid. The fluid forces are evaluated by the elongated body theory. Energy is dissipated all over the length of the membrane. A 20th scale experimental prototype has been designed with micro-dampers to simulate the power take-off. Trials have allowed to validate the undulating membrane energy convertor concept. A numerical model has been developed. Each element of the device is represented and the energy dissipation is done by dampers element with a damping law linear to damper velocity.Comparison of the three approaches validates their ability to represent the membrane behavior without damping. The energy dissipation applied with the analytical model is clearly different from the two other models because of the location (where the energy is dissipated) and damping law. The two others show a similar behavior and the same order of power take off repartition but value of power take off are underestimated by the numerical model. These three approaches have allowed to put forward key-parameters on which depend the behavior of the membrane and the parametric study highlights the complementarity and the advantage of developing three approaches in parallel to answer industrial optimization problems.To make the link between trials in flume tank and sea trials, a 1/6th prototype has been built. To do so, the change of scale was studied. The behavior of both prototypes is compared and differences could be explained by differences of boundary conditions and confinement effects. To evaluated membrane long-term behavior at sea, a method of aging accelerated by temperature and fatigue tests have been carried out on prototype materials samples immerged in sea water.