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Made available in DSpace on 2014-07-29T15:18:18Z (GMT). No. of bitstreams: 1 Dissertacao de Mestrado Ruiter da S Souza 2010.pdf: 3795319 bytes, checksum: ce03329bc9c991e1ebf4ddcb63aeada9 (MD5) Previous issue date: 2010-08-06 / Researches done in the last decades concerning the settlement of pile foundations, mainly when it s considered as piled raft, had greatly evolved due the progress on computational tools used in the analysis. However, the tridimensional analysis of a pile foundation, taking into account the interaction between your components (soil, piles and raft), is still a very complex problem. To achieve a satisfactory evaluation of the interaction between the foundation's elements, numerical tools like Boundary Elements Method (B.E.M.), Finite Elements Method (F.E.M.) and hybrid methods, that combines two or more methods, are available, each one with its own advantages and drawbacks. The F.E.M. is considered in the technical sphere as the most complete method for piled raft evaluation, but your high processing time requirements, required in the analyses, prevents your usual employment. For this reason, a necessity to compare this methodology with others, as the one used in simplified programs, that decreases the processing time, arises. To evaluate the results proximity achieved by different methods, this work presents the simulation of some pile blocks, calculated as piled rafts, employing two programs (GARP and DIANA) to foresee your behavior. GARP is a hybrid program which analyzes the raft by using F.E.M. and the pilessoil set by B.E.M. and, like the other programs of same kind published in the literature, it doesn't take the influence between intermediary piles into account for the analysis. DIANA is a purely finite elements program, based on the displacement method. Thus, the main objective of this work was to evaluate how taking or not the interaction factor between piles into consideration can modify the predictions of settlement and pile loads. For that, it was evaluated how the attribution or omission of these interaction factors into specific regions that comprise some or all the piles, modifies the predictions of the foundation performance and makes them approximate or distant from the F.E.M. results, considering the most exact one. The way that the simplified programs handle the problem, makes the settlement previsions excessive. To contour this and to make the settlement results from the simplified methods become close of the expected ones from F.E.M., the discovered way was the imposition of a limit in the distance used in the calculation of the piles interaction, based on the raft's size and the number of piles in that case. Many examples of pile rafts in homogeneous soils was evaluated and the maximum distance limits of interaction between piles that generated the best results in the settlement prevision are shown. In all examples, the effect of raft stiffness in these results was also taken into account. Also, an analysis case in heterogeneous soil was done, where it was observed that this fact also interferes in the piles interaction process. For pile load predictions, the results were distinct from settlement prediction and was noticed that not limiting the maximum interaction distance between the piles generated the best previsions. / As pesquisas realizadas nas últimas décadas sobre o recalque de fundações estaqueadas, principalmente quando a mesma é considerada como radier estaqueado, tiveram grande evolução devido ao avanço das ferramentas computacionais utilizadas nas análises. Porém, a análise tridimensional de uma fundação estaqueada considerando a interação entre seus componentes (solo, estacas e radier), continua sendo um problema muito complexo. Para uma avaliação satisfatória da interação entre os elementos da fundação, ferramentas numéricas como o Método de Elementos de Contorno (M.E.C.), o Método de Elementos Finitos (M.E.F.) e métodos híbridos, que combinam dois ou mais métodos, estão disponíveis, cada uma com suas vantagens e desvantagens. O M.E.F. é considerado pelo meio técnico como o método mais completo para avaliação de um radier estaqueado, mas seu alto tempo de processamento, tomado em grande parte das análises, impede que seu uso se torne mais corriqueiro. Com isso, surge a necessidade de se comparar essa metodologia com outras, como a usada em programas simplificados, que diminuem o tempo de processamento. Para a avaliação da proximidade dos resultados determinados por diferentes métodos, esta dissertação apresenta a simulação de alguns blocos de estacas, calculados como radiers estaqueados, utilizando dois programas para prever seus comportamentos, o GARP e o DIANA. O GARP é um programa híbrido que analisa o radier pelo M.E.F. e o conjunto estacas-solo pelo M.E.C. e, como os demais programas do gênero divulgados na literatura, não considera a influência de estacas intermediárias na análise. O DIANA é um programa de elementos finitos puro, baseado no método dos deslocamentos. Assim, o principal objetivo deste trabalho foi avaliar como a consideração ou não dos fatores de interação entre estacas pode modificar a previsão de recalques e carga nas estacas. Para isso, foi avaliado como a atribuição ou a omissão dos fatores de interação dentro de regiões específicas, que englobam algumas ou todas as estacas, modificam a previsão do desempenho da fundação e fazem com que se aproximem ou se distanciem dos resultados do M.E.F., considerado o mais exato. A forma como os programas simplificados tratam o problema faz com que suas previsões de recalques sejam excessivas. Para contornar este fato e fazer com que os resultados de recalques dos métodos simplificados sejam mais próximos dos previstos pelo M.E.F., a forma encontrada foi a imposição de um limite na distância usada no cálculo da interação entre as estacas, dependendo do tamanho do radier e número de estacas do caso. Vários exemplos de radiers estaqueados em solos homogêneos foram estudados e são apresentados os limites máximos da distância de interação entre estacas que originaram melhores resultados na previsão do recalque. Em todos os exemplos avaliou-se o efeito da rigidez do radier nestes resultados. Também foi analisado um caso em solo heterogêneo, onde se observou que este fato também interfere no processo de interação entre estacas. Para a previsão de carga nas estacas o resultado foi distinto da previsão de recalques e observou-se que a não limitação da distância máxima de interação entre estacas foi o que resultou em melhores previsões.

Les catalyseurs sont indispensables à l'industrie chimique moderne. La récupération des catalyseurs est nécessaire d'un point de vue économique et environnemental lorsqu'elle fait appel à des métaux coûteux et/ou toxiques. L'utilisation de la catalyse micellaire est un bon choix d'un point de vue de l'activité, du transfert de masse, et de recyclage mais comporte les problèmes de la formation d'émulsions stables liée au gonflement excessif et la perte physique du tensioactif libre en équilibre avec les micelles. L'objectif de ma thèse est réticuler les micelles au cœur pour éliminer ces problèmes. Après avoir construit de telles nanoparticules fonctionnalisées du ligand phosphine par la synthèse " one-pot " via PRC de type RAFT en émulsion. La première application des nanoréacteurs catalytiques a été réalisée en hydroformylation de l'octène en biphasique, donnant lieu à une conversion complète avec de faibles charges catalytiques, une décantation rapide et la possibilité de recycler le milieu catalytique. De manière inattendue, le catalyseur reste actif après une longue exposition à l'air, montrant un effet protecteur du polymère contre la dégradation du catalyseur. L'absence de coagulation à la fin de réaction est une preuve que ces nouveaux objets franchissent les limitations de la catalyse micellaire. / The catalytic processes are at the heart of chemical industry. Modern chemical industry, under pressure of stricter regulations and societal concern, is faced with the need to improve efficiency and cleaner production processes and catalysis is one the major keys to green chemical technology. Catalysts recovery is necessary from an economic and environmental point of view when it makes use of expensive and / or toxic metals. The aim of this thesis is based on an innovative approach related to micellar catalyst but in which the catalyst is covalent linked to the hydrophobic core of well-defined unimolecular, core-cross-linked micelles. The synthetic protocol is based on a convergent method via RAFT-mediated one-pot aqueous emulsion polymerization. The efficiency of these unimolecular micelles as catalytic nanoreactors has been shown using the industrially relevant hydroformylation of 1-octene, in order to provide a proof of principle, as a test reaction yielding turnover frequencies and l/b ratio comparable to those of related homogeneous systems. However, the catalyst phase could be easily separated from the organic product phase and recycled. A remarkable protecting effect of the active catalyst by the polymer scaffold has also been demonstrated. The absence of the coagulation at the end of reaction is evidence that these new objects function as micelles while eliminating the disadvantages of micellar catalysis such as the formation of stable emulsion.

Orientador: Liliane Maria Ferrareso Lona / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-07T23:37:08Z (GMT). No. of bitstreams: 1 Franco_IvanCarlos_M.pdf: 1044560 bytes, checksum: 8f4fdd66626d63245a2131f55b09f807 (MD5) Previous issue date: 2007 / Resumo: Polimerização via radical livre controlada (CRP) tem recebido cada vez mais atenção como uma técnica para produção de polímeros com micro estrutura altamente controlada. Em particular, distribuições de pesos moleculares estreitas são obtidas, com polidispersidade muito próxima de um, sendo um campo promissor na ciência de polimerização com estruturas controladas. Um importante requisito para engenharia de polimerização e desenvolvimento de polímeros é a construção de modelos matemáticos úteis, especialmente aqueles de natureza mecanística, com validação experimental. O objetivo deste trabalho é o desenvolvimento de modelos matemáticos abrangentes para simulação de polimerização para mecanismo RAFT. Metacrilato de metila em benzeno a 60°C na presença de 2,2-cianopropil 1- pirrolecarboditioato (agente RAFT) e com AIBN como iniciador em um reator batelada será considerado como estudo. Os pesos moleculares foram calculados utilizando o método dos momentos. Uma análise paramétrica considerando o efeito da concentração de iniciador e da concentração de agente RAFT foi realizada. O modelo predito está de acordo com os dados experimentais da literatura, o que atesta sua validade para ser utilizado no controle de estruturas poliméricas obtidas no processo RAFT / Abstract: Lately, Living Free Radical Polymerization (LFRP) has been detached as a technique for the production of polymers with highly controlled microstructure. In particular, narrow distributions of molecular weights are obtained, with polydispersity values next to one. So, this technique is a promising field in the science of polymerization with controlled structures. An important requirement for engineering of polymerization and polymer development is the construction of useful mathematical models, especially those of mechanistic nature, with experimental validation. The objective of this work was to develop comprehensive mathematical models to simulate polymerization from RAFT mechanism. Methyl Methacrylate in benzene at 60°C in the presence of 2-cyanoprop-2-yl 1-pyrrolecarbodithioate (agent RAFT) and with AIBN as the initiator in a batch reactor was considered. The molecular weights have been calculated using the method of moments. A parametric analysis considering the effect of the initiator and agent RAFT concentrations was performed. Models prediction showed good agreements with experimental data from literature, what certifies its validity in being used in the control of polymeric structures in RAFT process / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

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Wind farm construction is increasing progressively, to cope-up with the current global energy scenario. The advantage of clean energy and sustainability helps wind turbine construction to flourish rapidly. Location of wind turbines is independent of foundation soil condition but depends on the wind speeds and socio-environment issues. Hence, a construction sites may not be favorable in terms of geotechnical demands. The taller wind towers facilitate the generation of high energy production, which will increase loads on the foundation, and eventually increase the dimension of the foundation. Hence, the choice of a suitable foundation system is necessary for geotechnical engineer to design tall wind towers. This study aims to analyze different foundation types e.g., raft/mat foundation, pile group foundation, and piled raft/mat foundation using analytical calculation verified with numerical models using PLAXIS 3D software. The foundation for steel wind turbine towers 100 m high was designed for different types of soils e.g., soft clayey soil, medium-stiff clayey soil, stiff clayey soil, and sandy soil. The design wind speed was taken from the ASCE 7-10 (2010) standard for Occupancy Category III and IV Buildings and Other Structures, as the Illinois region falls in that category. The parametric study was performed by varying the diameter of raft/mat, wind speed, number of piles, and soil types to evaluate the settlement in any type of foundation with load sharing proportion in piled raft/mat foundation. First, the raft/mat foundation design was carried out manually by changing the diameter of 15 m, 20 m, 25 m, 30 m, and 35 m, and changing load by considering different wind speed. Then the foundation was modeled using PLAXIS 3D software with a raft/mat diameter of 25 m, 30 m, and 35 m only, by considering the eccentricity and factor of safety criteria. With the increase in wind speed, the differential settlement on the raft/mat foundation was found to be increased. However, the increase in diameter of raft/mat caused the reduction in differential settlement. Soft clayey soil was found to be more sensitive than other soils used in the present study. For the same diameter of raft/mat, applied the same wind load, the differential settlement of foundation in soft clayey soil was found to be 6-10 times higher than the sandy soil.The position of piles was fixed based on the spacing criteria in the pile group foundation. The number of piles used in this study were 23, 32, and 46. Settlement was found to be varied with the number of piles in all soils used in this study. The lateral deflection for soft clayey soil decreased to half, when number of piles increased from 23 to 46. The differential settlement was found to be increased with the increase in wind speed in pile group foundation. Raft/mat foundation settlement was found to be 4 to 6 times higher than the settlement in pile group foundation in any soils, used in this study, for a given wind speed.The result of piled raft/mat foundation showed that the majority of the total load is shared by the piles (i.e., 60% to 94%) and remaining load is shared by the raft/mat (i.e., 6% to 40%), based on the stiffness of raft/mat and piles as well as pile-soil-pile interaction. The increase in wind speed in the wind turbines increased the differential settlement of piled raft/mat foundation in all soils. Similarly, the lateral deflection also increased with the increase in wind speed in pile raft/mat foundation in all soils. The PLAXIS 3D analysis revealed that the differential settlement in soft clayey soil was 1.5 to 2.0 times higher than the settlement in sandy soil.The validation of numerical modeling was carried out by the raft/mat foundation using Boussinesq’s theory and calculating settlement for single pile and group pile foundation. The current study showed that the soft clayey soil and medium-stiff clayey soil favor deep foundation, like pile group and piled raft/mat rather than shallow foundation, like raft/mat foundation. The results obtained from both analytical calculation and numerical modeling was found to be approximately matching. This study will help local construction company and geotechnical engineer to guide a proper foundation design of tall onshore wind turbine.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第23222号 / 工博第4866号 / 新制||工||1759(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 秋吉 一成, 教授 大内 誠, 准教授 松岡 秀樹 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Resident cardiac Sca-1-positive (+) stem cells may differentiate into cardiomyocytes to improve the function of damaged hearts. However, little is known about the inducers and molecular mechanisms underlying the myogenic conversion of Sca-1+ stem cells. Here we report that sphingosylphosphorylcholine (SPC), a naturally occurring bioactive lipid, induces the myogenic conversion of Sca-1+ stem cells, as evidenced by the increased expression of cardiac transcription factors (Nkx2.5 and GATA4), structural proteins (cardiac Troponin T), transcriptional enhancer (Mef2c) and GATA4 nucleus translocation. First, SPC activated JNK and STAT3, and the JNK inhibitor SP600125 or STAT3 inhibitor stattic impaired the SPC-induced expression of cardiac transcription factors and GATA4 nucleus translocation, which suggests that JNK and STAT3 participated in SPC-promoted cardiac differentiation. Moreover, STAT3 activation was inhibited by SP600125, whereas JNK was inhibited by β-cyclodextrin as a lipid raft breaker, which indicates a lipid raft/JNK/STAT3 pathway involved in SPC-induced myogenic transition. β-Catenin, degraded by activated GSK3β, was inhibited by SPC. Furthermore, GSK3β inhibitors weakened but the β-catenin inhibitor promoted SPC-induced differentiation. We found no crosstalk between the lipid raft/JNK/STAT3 and β-catenin pathway. Our study describes a lipid, SPC, as an endogenic inducer of myogenic conversion in Sca-1+ stem cells with low toxicity and high efficiency for uptake.

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