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This research investigates wave propagation in an elastic half-space with a quadratic nonlinearity in its stress-strain relationship. Different boundary conditions on the surface are considered that result in both one- and two-dimensional wave propagation problems. The goal of the research is to examine the generation of second-order frequency effects and static effects which may be used to determine the nonlinearity present in the material. This is accomplished by extracting the amplitudes of those effects in the frequency domain and analyzing their dependency on the third-order elastic constants (TOEC). For the one-dimensional problems, both analytical approximate solutions as well as numerical simulations are presented. For the two-dimensional problems, numerical solutions are presented whose dependency on the material's nonlinearity is compared to the one-dimensional problems. The numerical solutions are obtained by first formulating the problem as a hyperbolic system of conservation laws, which is then solved numerically using a semi-discrete central scheme. The numerical method is implemented using the package CentPack. In the one-dimensional cases, it is shown that the analytical and numerical solutions are in good agreement with each other, as well as how different boundary conditions may be used to measure the TOEC. In the two-dimensional cases, it is shown that there exist comparable dependencies of the second-order frequency effects and static effects on the TOEC. Finally, it is analytically and numerically investigated how multiple reflections in a plate can be used to simplify measurements of the material nonlinearity in an experiment.

Les tunnels profonds sont souvent construits dans les roches sédimentaires et métamorphiques stratifiées qui présentent habituellement des propriétés anisotropes en raison de leur structure et des propriétés des constituants. Le présent travail vise à étudier les tunnels profonds dans un massif rocheux anisotrope élastique en portant une attention particulière sur les effets des couplages hydromécaniques par des approches analytiques et numériques. Une solution analytique pour un tunnel creusé dans un massif rocheux anisotrope saturé est développée en tenant compte du couplage hydro-mécanique dans le régime permanent. Cette solution analytique est utilisée pour réaliser une série d’études paramétriques afin d'évaluer les effets des différents paramètres du matériau anisotrope sur le comportement du tunnel. Dans un deuxième temps la solution analytique est élargie pour décrire le comportement du tunnel pendant la phase transitoire hydraulique. Afin de compléter ces études analytiques qui prennent en compte seulement un couplage unilatéral (dans le sens que seul le comportement hydraulique influence le comportement mécanique et pas l’inverse) de l’analyse numérique avec un couplage complet, ont été réalisés. Une application de la solution analytique sur la méthode de convergence-confinement est aussi bien abordée qui peut prendre en compte l'influence du front de taille du tunnel sur le travail du soutènement ainsi que sur le massif. La solution obtenue peut servir comme un outil de dimensionnement rapide des tunnels en milieux poreux en le combinant avec des approches de dimensionnement comme celle de convergence confinement. / Deep tunnels are often built in the sedimentary and metamorphic foliated rocks which exhibits usually the anisotropic properties due to the presence of the discontinuity. The analysis of rock and liner stresses due to tunnel construction with the assumption of homogeneous and isotropic rock would be incorrect. The present thesis aims to deal with the deep tunnel in anisotropic rock with a particular emphasis on the effects of hydraulic phenomenon on the mechanical responses or reciprocal effects of hydraulic and mechanical phenomena by combining analytical and numerical approach. On that point of view, a closed-formed solution for tunnel excavated in saturated anisotropic ground is developed taking into account the hydromechanical coupling in steady-state. Based on the analytical solution obtained, parametric studies are conducted to evaluate the effects of different parameters of the anisotropic material on the tunnel behavior. The thesis considers also to extend the analytical solution with a time-dependent behavior which takes into account the impact of the pore pressure distribution on mechanical response over time, i.e., one way coupling modeling. In addition, some numerical analysis based on fully-coupled modeling, i.e., two ways coupling, are conducted which are considered as the complete solution for the analytical solution. An application of the closed-form solution on convergence-confinement method is as well referred which can take into account the influence of the tunnel face on the work of the support as well as the massif. The obtained solution could be used as a quick tool to calibrate tunnels in porous media by combining with design approaches such as convergence-confinement method.

L’objectif de ce travail fut d’améliorer la modélisation et la simulation de la polymérisation radicalaire dans des réacteurs continus et discontinus. Une solution analytique explicite généralisée (AS) fut obtenue dans le cas de la polymérisation en masse/solution, homogène et isotherme menée dans un réacteur fermé de volume variable. Les différentes étapes considérées furent l'initiation, la propagation, le transfert au monomère, au solvant, à un agent de transfert de chaîne, la terminaison par combinaison et dismutation. Différents modèles rendant compte des effets de gel, de vitrification et de cage ont également été considérés. AS a été validée avec succès par comparaison avec des solutions numériques et des données expérimentales de la littérature. Par ailleurs, AS a été étendue à des conditions pour lesquelles elle ne fut pas originellement développée comme par exemple des conditions non isothermes. La polyvalence et la flexibilité de AS sur l’ensemble de l’échelle de conversion du monomère furent ainsi démontrées. Ensuite, pour élargir encore plus son champ d'application, AS fut utilisée dans des simulations numériques (CFD). Une nouvelle transformation très simple a été proposée afin d’adimensionnaliser les constantes cinétiques en terme de concentration. Cela a permis de rentrer dans les simulations les données chimiques sous leur forme originale en mole et de faciliter ainsi le codage et le débogage du code de calcul. Cette transformation a ensuite été utilisée pour évaluer trois géométries tubulaires de microréacteur, un réacteur tubulaire droit (STR), à géométrie hélicoïdale (CTR) et à inversion de flux (CFIR), dans des conditions d'alimentation différentes (fluides d’entrée non ou parfaitement mélangés) et à de très faibles nombres de Reynolds (<1). La modélisation a été réalisée avec des paramètres constants ou variables des propriétés physiques du fluide sous écoulement (densité, viscosité et conductivité thermique) ainsi qu’en variant de manière discrète les coefficients de diffusion. Leurs effets sur les résultats de simulation ont été observés et comparés avec les données expérimentales publiées pour 4 monomères différents et furent en très bon accord. Les résultats pour le cas d’un mélange parfait furent indépendants de la géométrie des microréacteurs. Le CFIR semble être le réacteur le plus prometteur puisque, dans les conditions de microréaction étudiées, il a permis le meilleur contrôle des caractéristiques du polymère synthétisé. / This thesis aimed at improving the modeling and simulation of free radical polymerization (FRP) in batch as well as in flow reactors. A generalized explicit analytical solution (AS) was obtained in case of variable volume, bulk/solution polymerization, homogeneous and isothermal batch reactor. The reaction steps included initiation, propagation, transfer to monomer, transfer to solvent, transfer to chain transfer agent (CTA), termination by combination and disproportionation. Different models of gel, glass and cage effects were also implemented explicitly. AS was validated against numerical solutions as well as published experimental data and was found in good agreement. Furthermore, its applicability was extended to conditions for which AS was not derived, i.e. non-isothermal conditions. The versatility and flexibility of AS over the complete range of monomer conversion were thus demonstrated. Then, to broaden its applications range even more, AS was used in CFD simulations. A new and simple transformation was proposed to make kinetic rate coefficients dimensionless in terms of concentration. This enabled chemical data to be fed in molar form to CFD modeling. It also enabled easy coding and debugging by keeping the original form of generation terms intact. The results were found to be improved after validation against experimental data. This transformation was then used for evaluating three tubula microreactor geometries, namely straight tube reactor (STR), coiled tube reactor (CTR) and coil flow inverter reactor (CFIR), under different feed conditions (unmixed or perfectly mixed) at very low Reynolds numbers (<1). The modeling for FRP was performed with constant or variable fluid physical parameters (density, viscosity and thermal conductivity) along with discrete variation of diffusion coefficients. Their effects on simulation results were observed and compared with published experimental data for 4 different monomers and were found to match perfectly. Results for mixed feed condition were found to be independent of microreactor geometry. CFIR seems to be the most promising reactor design under microreaction investigated conditions as it allowed the best control over polymer characteristics.

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T09:28:13Z No. of bitstreams: 0 / Made available in DSpace on 2016-11-11T09:28:13Z (GMT). No. of bitstreams: 0 / O monocloroacetato de sódio (MCAS) e o dicloroacetato de sódio (DCAS) são compostos tóxicos e irritantes ao ser humano e nocivos ao meio ambiente, sendo impurezas indesejáveis na cocoamido propil betaína (CAPB), que é um surfactante anfótero utilizado em produtos de consumo dos segmentos cosmético e domiciliar. Diante dos requisitos de concentração em nível de mg/kg exigidos pelos órgãos reguladores de saúde do governo, tornou-se mandatório o emprego de metodologia com limite de quantificação, precisão e exatidão adequados aos rígidos controles de processo pelos fabricantes da CAPB, bem como, dispor de técnicas convencionais com poder de resolução e proficiência pelo controle de qualidade e neste contexto inseriu-se a cromatografia a gás. Neste estudo foram estabelecidos os procedimentos analíticos que definiram as melhores condições para identificar e quantificar as impurezas MCAS e DCAS na matriz CAPB por meio da cromatografia a gás. A preparação das amostras consistiu da derivação das impurezas MCAS e DCAS a ésteres etílicos e a extração líquido-líquido em hexano para separar dos demais constituintes da matriz. Os modos de detecção acoplados à cromatografia a gás foram a ionização pela chama (GC/FID), a captura de elétrons (GC/ECD) e a espectrometria de massas (GC/MS). A validação comprovou que as metodologias são lineares entre 4 e 50 mg/kg com recuperação de 70 a 120%, apresentam limites de quantificação inferiores a 10 mg/kg e produziram médias e incertezas similares na amostra examinada, constituindo-se alternativas para a determinação de cloroacetatos em betaínas. / Dissertação (Mestrado em Tecnologia Nuclear) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2016-11-11T13:30:20Z No. of bitstreams: 0 / Made available in DSpace on 2016-11-11T13:30:20Z (GMT). No. of bitstreams: 0 / Desde que foi reconhecida a importância de se planejar um turismo sustentável, tem-se buscado ferramentas adequadas para monitorá-lo nas destinações turísticas, tornando esse um dos principais desafios da academia científica de estudos do turismo na atualidade. Diante desse contexto, o desafio apresenta-se ainda maior, quando tratamos de turismo em unidades de conservação, tendo em vista que envolve um ambiente altamente sensível e comunidades em seu entorno que podem ter, no desenvolvimento dessa atividade, sua principal renda econômica. Assim, o que se propõe neste estudo é analisar a aplicabilidade e a eficiência metodológica do monitoramento que visa ao auxílio na construção da sustentabilidade do turismo, em unidades de conservação, através de um estudo de caso no Parque Estadual do Jalapão, localizado no Estado do Tocantins, Brasil. Prioriza-se a investigação de indicadores locais abordados a partir da definição estipulada pela Organização Mundial do Turismo. Os resultados alcançados demonstraram que os indicadores estudados são instrumentos a serem considerados no processo de avaliação e quantificação do turismo em um destino com semelhantes configurações ambientais, o que viabiliza a compreensão e o fortalecimento da noção de sustentabilidade. Este estudo caracteriza-se pela sua vertente interdisciplinar e teve como norteador o método dedutivo. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Submitted by Marco Antonio Oliveira da Silva (maosilva@ipen.br) on 2016-12-21T17:42:04Z No. of bitstreams: 0 / Made available in DSpace on 2016-12-21T17:42:04Z (GMT). No. of bitstreams: 0 / Os catalisadores eletroquímicos binários de PtSn/C, PdSn/C e PtPd/C foram sintetizados em diferentes proporções pelo método da redução via borohidreto, posteriormente estes foram caracterizados por microscopia eletrônica de transmissão, difração de raios X, espectroscopia no infravermelho por transformada de Fourier (PtSn/C e PdSn/C) e energia dispersiva de raios X. As atividades eletroquímicas dos diferentes materiais preparados foram avaliadas por intermédio de voltametria cíclica, cronoamperometria e curvas de polarização em célula a combustível alimentada diretamente por etileno glicol em eletrólito alcalino. As curvas de densidade de potência indicaram que os catalisadores eletroquímicos contendo Sn e Pd são mais ativos para a reação de oxidação do etileno glicol, especialmente a composição 70%:30% - relação molar entre os metais suportados em carbono - dos catalisadores PtSn/C, PdSn/C e PtPd/C todos superando as medidas de potência do Pt/C. Este resultado indica que a adição de Sn e Pd favorece a oxidação do etileno glicol em meio alcalino. O melhor desempenho observado para os catalisadores eletroquímicos PtSn/C, PdSn/C e PtPd/C (70%:30%) poderia estar associado à sua maior seletividade quanto a formação de oxalato, ou seja , a formação deste produto resulta em um maior número de elétrons, por consequência em maiores valores de corrente. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Die verlässliche Vorhersage der Wärmeentzugsleistungen als auch der Soletemperaturen in den Sonden sind wichtig für deren Auslegung und Betriebsoptimierung. Es ist ebenso wichtig für die Auslegung und Optimierung der Anlagen im versorgten Gebäude. In der vorliegenden Dissertation wurde versucht, durch eine mathematische Weiterentwicklung von Greenschen Funktionen (g-Funktionen) eine präzisere Lösung für Temperaturverteilung im Erdreich infolge des von einer oder mehreren Sonden verursachten Wärmeentzuges mit verschiedenen Randbedingungen im geologischen Untergrund zu erreichen. Hierzu wurden sechs „neue“ g-Funktionen entwickelt, die vertikal variable Wärmeentzüge einzelner Sonden und Sondenfelder, eine Asymmetrie des Wärmeentzuges der Sonde, den Einfluss einer zusätzlichen Grundwasserströmung und den realen, geschichteten Untergrund berücksichtigen. Die mathematischen Modelle des Erdreichs wurden mit Modellen für die Soleströmung und Wärmeübergabe in der Hinterfüllung der Sonde gekoppelt und anschließend auf ein praktisches Betriebsbeispiel angewendet. Die Arbeit enthält ebenfalls umfangreiche Sichtung existierender Modelle sowie deren Anwendung und vergleichende Bewertung der teilweise komplexen Modellansätze.:Formelzeichen und Abkürzungen 1 Einführung 2 Energiequellen und Aufbau der Erdwärmeübertrager 2.1 Quellen der geothermalen Energie 2.2 Aufbau der Erdwärmeübertrager 2.3 Betriebsverhalten von Erdwärmesonden 2.4 Auslegung der Sonden 3 Vorhandene Modelle 3.1 Soleströmung 3.2 Wärmeübergang in den Rohren der Sonde 3.3 Wärmeleitung in der Hinterfüllung 3.4 Erdreichmodellierung – numerisch 3.5 Erdreichmodellierung mit g-Funktionen 4 Weiterentwicklung der analytischen Modelle 5 Anwendungsbeispiele 185 5.1 Ein praktisches Beispiel 5.2 Auswirkung auf die Jahresarbeitszahl 6 Zusammenfassung Literatur A Ableitung der Bohrlochwiderstände B Ableitung der Funktionen für Randbedingungen C Eidesstattliche Erklärung / The design of the ground heat exchangers (GHE) systems demands the precise prediction of their heat output and the brine temperature. The same information is needed for design and optimization of the HVAC systems coupled to GHEs. In the thesis at hand the Green’s functions (g-Functions) have been used to develop the more accurate solutions for the temperature distribution in soil resulting from the heat extraction from one GHE or a field of GHEs. These solutions consist of six novel g-functions that take account of the vertical variation of the extracted heat flux in one GHE or field of GHEs, of the horizontal ground water flow and of the horizontal variation of the soil properties. The models for prediction of the soil temperature have been coupled with models for brine flow and heat transfer in the GHE’s grout and eventually applied to the simulation of the real world object. Additionally, the thesis contains broad review of the known models and their applications as well as the comparative analysis of the complex modelling assumptions.:Formelzeichen und Abkürzungen 1 Einführung 2 Energiequellen und Aufbau der Erdwärmeübertrager 2.1 Quellen der geothermalen Energie 2.2 Aufbau der Erdwärmeübertrager 2.3 Betriebsverhalten von Erdwärmesonden 2.4 Auslegung der Sonden 3 Vorhandene Modelle 3.1 Soleströmung 3.2 Wärmeübergang in den Rohren der Sonde 3.3 Wärmeleitung in der Hinterfüllung 3.4 Erdreichmodellierung – numerisch 3.5 Erdreichmodellierung mit g-Funktionen 4 Weiterentwicklung der analytischen Modelle 5 Anwendungsbeispiele 185 5.1 Ein praktisches Beispiel 5.2 Auswirkung auf die Jahresarbeitszahl 6 Zusammenfassung Literatur A Ableitung der Bohrlochwiderstände B Ableitung der Funktionen für Randbedingungen C Eidesstattliche Erklärung

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