Thesis (Ph.D.)--York University, 2005. Graduate Programme in Earth and Space Science. / Typescript. Includes bibliographical references (leaves 260-268). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://wwwlib.umi.com/cr/yorku/fullcit?pNR11542

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Le développement de couches minces dopées terres rares a suscité un regain d'intérêt au cours des dernières années. Dans ce mémoire nous présentons l'élaboration des couches minces d'yttria (Y2O3), d'alumine (Al2O3) et les couches mixtes Y2O3-Al2O3 dopées erbium. La technique utilisée est le procédé de dépôt chimique en phase vapeur à partir de précurseurs organométallique (MOCVD) assisté par aérosol. Un dispositif d'irradiation UV est appliqué afin d'assister le processus de réaction avec une modification de l'hygrométrie de l'air vecteur. Les meilleures propriétés sont obtenues pour les couches déposées sous une forte humidité de l'air vecteur et avec l'assistance UV. Dans ces conditions les couches d'yttria présentent une faible vitesse de croissance, une faible contamination organique et une bonne cristallinité dans la phase cubique de l'yttria. Plusieurs phénomènes d'Up-conversion ont été mis en évidence dans les spectres de fluorescence visible de l'erbium dans l'yttria. Une durée de vie du niveau 4I13/2 de l'erbium de 3.07 ms a été mesurée pour ce matériau après recuit à 800°C. Cette valeur est supérieure à celle obtenue pour l'échantillon déposé sous une faible humidité de l'air et sans l'assistance UV après recuit à 1000°C. Les couches d'alumine déposées dans les conditions optimales présentent des vitesses de croissance élevées et se caractérisent par une grande stabilité thermique, permettant l'élimination complète des impuretés tout en restant amorphe. Enfin, l'étude du système Y2O3-Al2O3 montre que les conditions de dépôt jouent un rôle important sur la composition et les propriétés physico-chimiques des dépôts. / The development of rare earth-doped thin film has gained interest over these last few years. In this report we present the elaboration of erbium-doped yttria (Y2O3), alumina (Al2O3) and yttria-alumina (Y2O3-Al2O3) films. The technique used is aerosol assisted chemical vapor deposition processes with metalorganic precursors (MOCVD). A UV-irradiation device is applied to assist the reaction process with a modification in the air humidity of the carrier gas. The best properties are obtained on thin films grown under high air humidity and with UV-assistance. Under such deposition conditions the yttria films present a low growth rate, low organic contamination and higher crystallisation degree in the yttria cubic structure. Several up-conversion phenomena are point out in the visible fluorescence spectra of the erbium ion in yttria. A lifetime of the 4I13/2 Er3+ level of 3.07 ms was found in this material after annealing at 800°C. This value is higher than that obtained for the sample deposited under low air humidity and without UV assistance after annealing at 1000°C. Alumina film deposited under optimal conditions show high growth rate and was a high thermal stability; allow the complete elimination of impurities while remaining amorphous. At last, the results of system Y2O3-Al2O3 indicates that deposition conditions play an important role on the composition and physicochemical properties of films.

Orientador: Carlos Alberto dos Reis Filho / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Eletrica e Computação / Made available in DSpace on 2018-08-05T22:28:31Z (GMT). No. of bitstreams: 1 ManzanJunior_Donato_M.pdf: 1716370 bytes, checksum: 70e88e04a73f17039cb0ea8597b7b0cc (MD5) Previous issue date: 2005 / Resumo: Este trabalho descreve o desenvolvimento de um sensor de umidade relativa que tem como elemento sensor um polímero (poli(óxido de etileno-co-epicloridrina)84:16), cuja condutividade varia com a umidade. O polímero foi depositado por casting sobre um substrato cerâmico sobre o qual, por sua vez, foram depositados dois eletrodos em forma interdigitada aos quais é aplicada uma corrente alternada com forma de onda quadrada e amplitude DC nula. Este sinal de excitação é produzido por um circuito integrado que também realiza a leitura da tensão nos terminais do eletrodo. Além disto, o circuito contém um sensor de temperatura cuja informação é necessária para a correta leitura da umidade. Amostras do circuito integrado, cujo projeto é parte deste trabalho, foram fabricadas em tecnologia CMOS 0,35um e caracterizadas juntamente com o elemento sensor. Os resultados mais relevantes da caracterização do sensor desenvolvido são: Faixa de medição: máx 90%RH para evitar condensação; Sensibilidade do elemento sensor: 188,83W/%RH a 55%RH; Histerese: 3,4% a 55%RH; Temperatura de operação: 0 a 60oC; Tempo de resposta: +/-30s. A principal contribuição deste trabalho reside na proposição de um sensor de umidade que é composto de um elemento sensor polimérico e de um circuito integrado que realiza o condicionamento e leitura dos sinais envolvidos, constituindo deste modo uma solução robusta e de baixo custo / Abstract: This work describes the development of a relative-humidity sensor, which uses as sensing element a polymer (poly(ethylene oxide-co-epichlorohydrin)84:16) whose conductivity varies with humidity. The polymer was deposited by casting over a ceramic substrate, on which two interdigitized electrodes were previously deposited. An integrated circuit, also developed as part of the work, provides a square wave current with no DC component as excitation signal to the electrodes and reads the voltage across them. The developed integrated circuit also includes a temperature sensor, whose produced signal is used to yield the correct humidity measurement. Samples of the integrated circuit were fabricated in 0.35µm CMOS technology and were characterized together with the sensing element. The most relevant characteristics of the developed humidity sensor are: Measuring range: 90%RH max, to avoid condensing; Sensor element sensitivity: 188,83W/%RH at 55%RH; Hysteresis: 3,4% at 55%RH; Operating temperature: 0 to 60oC; Response time: +/-30s. The main contribution of this work is the proposition of a humidity sensor, which is based on a compound of a polymeric sensing element that operates in conjunction with an integrated circuit. The developed integrated circuit performs the necessary conditioning of the involved signals, in addition to include a temperature sensor. The developed humidity sensor has proven to be robust and can be produced at a relative low cost / Mestrado / Eletrônica, Microeletrônica e Optoeletrônica / Mestre em Engenharia Elétrica

Les travaux de cette thèse se sont intéressés à l’obtention du comportement d’un composite sergé 2x2 verre/PA66 via un outil numérique basé sur une double homogénéisation : la première concerne les torons et la seconde le volume élémentaire représentatif du composite. A partir d’une campagne de caractérisation expérimentale sur le PA66, nous avons dans un premier temps identifié l’influence à la fois de l’hygrométrie et de la température sur le comportement de la matrice en quasi-statique. Ensuite, nous avons élaboré, implémenté et validé une loi de comportement isotrope élasto-plastique endommageable. Cette loi a servi à identifier par homogénéisation le comportement des torons en supposant un collage parfait des fibres et de la matrice ainsi qu’une homogénéité de l’eau dans le toron. Grâce à ces comportements identifiés et à l’élaboration d’une loi de comportement anisotrope élasto-plastique endommageable, nous avons pu déterminer les caractéristiques élastiques dans un premier temps et les comportements longitudinaux et en cisaillement dans un second temps. Les comparaisons aux résultats expérimentaux menés sur le composite offrent des résultats satisfaisants et permettent de penser que l’outil numérique développé, permettrait, à termes, d’aider à une conception rapide incluant ce genre de matériau en diminuant le nombre d’essais expérimentaux à faire. Des perspectives enfin sont proposées notamment pour l’extension aux comportements en dynamique (crash). / The objective of this PhD thesis is to create a methodology to simulate the behavior of a 2x2 glass/PA66 twill composite using homogenization. To achieve this goal, we use two steps: first one is dedicated to represent the yarn behavior and the second one to represent the behavior of the composite RVE. An experimental characterization campaign about the PA66 has been done in order to quantify the influence of both hygrometry and temperature on the behavior of the matrix in quasi-static. Then, we formulated, implemented and validated an isotropic elasto-plastic damageable constitutive law. It was used to identify by homogenization the behavior of the yarns by assuming a perfect bonding of the fibers and the matrix as well as a water homogeneity inside the yarn. Thanks to the identified behavior of the yarns and by formulating a compatible constitutive law (anisotropic elasto-plastic damageable), we have determined for the woven composite on one hand the elastic properties and in the other hand the longitudinal/transversal and shear nonlinear behaviors. The comparisons of the numerical and experimental results offer satisfactory results. It provides good outlook in short-term in regard of structures design which include this type of woven composite materials. The main advantage of the methodology is to decrease the number of required experimental tests. Some outlook dedicated to crash studies are finally suggested.

CAPES; CNPq / No presente estudo, de campo e experimental,foram confeccionados corpos de prova em papel, os quais foram expostos a diferentes condições naturais de temperatura e umidade relativa em duas bibliotecas universitárias, localizadas em Curitiba (910 m acima do nível do mar) e em Caiobá, no Litoral Paranaense. Os papéis foram produzidos com celulose de fibra curta e fibra longa, sem adição de cargas ou adesivos, de modo a possibilitar o estudo das inter-relações entre a degradação das amostras e as condições ambientais de ambas as bibliotecas, comparativamente ao ambiente externo. O objetivo da pesquisa foio de avaliar o impacto das condições higrotérmicas em coleções em papel, por meio de medições dos parâmetros de temperatura e umidade relativa e da exposição de corpos de prova a quatro situações distintas: biblioteca central da Universidade Tecnológica Federal do Paraná verificar qual dos contextos climáticos (interna e externamente às bibliotecas), com variação cíclica de temperatura e umidade relativa, apresenta maior potencial de preservação das amostras, comparativamente aos índices de preservação (Isopermanência) IP e Índice Efeito Tempo de Preservação IETP (que quantificam os efeitos de Temperatura e Umidade Relativa sobre a expectativa de vida dos papéis. As amostras foram acondicionadas em caixas de acrílico revestidas com manta de carvão ativado e com filtroultra violeta -UV de forma que os efeitos da temperatura e umidade atuassem nos corpos de prova sem interferência de outros fatores de degradação como os gases poluentes e a luz. Na exposição das amostras no ambiente interno, apenas as caixas de acrílico são adotadas, no espaço externo contou-se adicionalmente com abrigos meteorológicos, construídos de acordo com padrões da World Meteorological Organization(WMO), dentro dos quais foram depositadas as caixas de acrílico naturalmente ventiladas. Os dados climáticos foram registrados em dataloggerse os corpos de prova foram enviados para ensaios físico-químicos antes e após 12 e 24 meses de exposição. Os resultados dos ensaios indicam que os maiores índices de degradação estão correlacionados com aqueles apontados pelas equações de IP/IETP (que relacionam temperatura ambiente e umidade relativa) como os de menor permanência para o papel. / In this study, paper samples were produced and naturally exposed to varying temperature and humidity conditions at two university libraries, located in Curitiba (910m a.m.s.l.) and in Caiobá, on the coast of Paraná state. The paper samples were produced with unloaded long-and short-fiber cellulose, without adhesives, in order to facilitate the analysis of the relationship between sample decay rate and natural ageing conditions at both libraries, relative to outdoors. The purpose of the research was to identify which climatic context presents the highest paper preservation potential, by means of the preventive conservation indices PI and TWPI (Preservation Index and the Time Weighted Preservation Index), which quantify the effects of temperature and humidity on paper life expectancy. The samples were placed in naturally ventilated acrylic containers covered with UV film, whose openings were protected with activated charcoal so that temperature and humidity had the major effects on the paper samples. For outdoors, Stevenson screens were used, wherein the acrylic containers were placed. Climatic data were recorded with data loggers and the paper samples were tested with regard to physical and chemical properties before and after a 12and 24 months natural exposure. Results indicate the largest decay rates for the samples with the shortest life expectancy according to PI/TWPI (obtained from ambient temperature and relative humidity) estimates. / 5000