Le béton est un matériau hétérogène complexe dont les déformations comportent une partie différée qui est affectée par un grand nombre de facteurs tels que la température, l'humidité relative et l'évolution de la microstructure. La prise en compte des déformations différées et en particulier du fluage est indispensable dans le calcul des ouvrages en béton tels que ceux destinés à stocker des déchets radioactifs. Ce travail de thèse a pour objectifs : (1) de développer un modèle de fluage simple et robuste pour le béton en faisant appel à la micromécanique et en tenant compte de l'endommagement et des effets thermiques et hydriques ; (2) d'implanter numériquement le modèle développé dans un code de calcul par éléments finis de façon à pouvoir simuler le comportement d'éléments de structure simples en béton. Pour atteindre ce double objectif, le travail est scindé en trois parties. Dans la première partie, le matériau cimentaire est à l'échelle microscopique supposé être constitué d'une matrice viscoélastique linéaire caractérisée par un modèle de Maxwell généralisé et de phases particulaires représentant les granulats élastiques et les pores. Le schéma micromécanique de Mori-Tanaka, la transformée de Laplace-Carson et son inversion sont alors utilisés pour obtenir dans l'espace temporel des estimations analytiques ou numériques de ses paramètres mécaniques et hydromécaniques. Ensuite, le modèle micromécanique de fluage obtenu est couplé au modèle d'endommagement de Mazars via le concept de pseudo-déformations introduit par Schapery. Les paramètres intervenant dans le modèle viscoélastique endommageable ainsi établi sont systématiquement identifiés à l'aide de données expérimentales. Enfin, la prise en compte des effets de la température et de l'humidité relative dans le modèle viscoélastique endommageable est basée sur la méthode du temps équivalent ; l'efficacité de cette approche est démontrée et discutée dans le cas de chargements simples de fluage / Concrete is a complex heterogeneous material whose deformations include a delayed part that is affected by a number of factors such as temperature, relative humidity and microstructure evolution. Taking into account differed deformations and in particular creep is essential in the computation of concrete structures such as those dedicated to radioactive waste storage. The present work aims: (1) at elaborating a simple and robust model of creep for concrete by using micromechanics and accounting for the effects of damage, temperature and relative humidity; (2) at numerically implementing the creep model developed in a finite element code so as to simulate the behavior of simple structural elements in concrete. To achieve this twofold objective, the present work is partitioned into three parts. In the first part the cement-based material at the microscopic scale is taken to consist of a linear viscoelastic matrix characterized by a generalized Maxwell model and of particulate phases representing elastic aggregates and pores. The Mori-Tanaka micromechanical scheme, the Laplace-Carson transform and its inversion are then used to obtain analytical or numerical estimates for the mechanical and hydromechanical parameters of the material. Next, the original micromechanical model of creep is coupled to the damage model of Mazars through the concept of pseudo-deformations introduced by Schapery. The parameters involved in the creep-damage model thus established are systematically identified using available experimental data. Finally, the effects of temperature and relative humidity are accounted for in the creep-damage model by using the equivalent time method; the efficiency of this approach is demonstrated and discussed in the case of simple creep tests

O Bioma Cerrado, ao longo da história de ocupação pelo homem, vem sendo explorado em detrimento da redução de sua biodiversidade. Dentre as várias características típicas da vegetação do cerrado, nesta tese, um maior destaque é dado às veredas que se alinham ao sistema hidrográfico acompanhando seu traçado e formando um corredor de cobertura vegetal de porte arbóreo, muito utilizado pela fauna local como fonte de alimentação, reprodução e abrigo, favorecendo o fluxo gênico local, como parte do processo natural de manutenção dos ecossistemas ali presente formadores do Bioma Cerrado. Em vista da importância da preservação ambiental do cerrado, foi criado o Parque Estadual Veredas do Peruaçu que está localizado na região norte de Minas Gerais, onde também, estão instaladas propriedades rurais que concentram suas atividades na exploração agrícola e pecuária. Neste contexto, o próprio rio Peruaçu configura-se como o limite geográfico entre esta Unidade de Conservação e as propriedades rurais ali próximas que, frequentemente, o ultrapassam como forma de ampliação de suas áreas produtivas, além da caça e corte de madeira para produção de carvão, comprometendo a preservação dos ambientes de veredas ali existentes, modificando também as características microclimáticas daquele ambiente, verificada na área de estudo, através da coleta de dados, quando verificou-se que aqueles ambientes modificados pela ação antrópica apresentaram temperatura do ar (°C) mais altas e umidade relativa do ar (%) menor. / The Cerrado, throughout the history of occupation by man, has been deployed at the expense of reduced its biodiversity. Among the various characteristics of the vegetation cerrado, in this thesis, a greater emphasis is given to paths that line the river system following its track and forming a corridor of vegetation cover trees, often used by local wildlife as source of food, shelter and reproduction, favoring local gene flow, as part of the natural maintenance of ecosystems present there trainers Cerrado. In view of the importance of environmental preservation cerrado was created State Park Trails Peruaçu which is located in the northern region of Minas Gerais, where also rural properties that are installed focus their activities on the farm and livestock. In this context, the river itself Peruaçu configures itself as the geographical boundary between this unit and Conservation farms near here that often the excess as a way of expanding their areas productive than hunting and logging production coal, jeopardizing the preservation of environments paths that exist there, also changing the microclimatic characteristics of that environment, observed in the study area, through data collection, when it was found that these modified environments by human action were air temperature (° C) higher and relative humidity (%) lower.

No presente trabalho propomos a utilização de uma técnica refratométrica baseada na determinação do ângulo crítico para o desenvolvimento de um sensor de umidade relativa e, no mesmo escopo de aplicação, um medidor de vácuo primário. A técnica proposta tira vantagem da diferença de fase adquirida pelas componentes paralela e perpendicular de um feixe luminoso, linearmente polarizado, passando por reflexão interna, para produzir um laser de HeNe sintonizável, um polarizador, um prisma semicilíndrico de índice de refração conhecido fabricado em vidro tipo flint, um analisador, um mínimo de intensidade, facilmente detectável no perfil refletido correspondendo à posição do ângulo crítico. Desenvolvemos um estudo acerca dos principais aspectos teóricos envolvidos no fenômeno da reflexão total interna, onde realizamos algumas simulações buscando avaliar as variações da posição angular do ângulo crítico a partir de alterações no índice de refração. A montagem básica utilizada nos experimentos consiste de um CCD linear e de um computador, onde as informações coletadas pelo CCD foram tratadas por meio de um programa de aquisição de dados desenvolvido na plataforma LabVIEWTM. O programa empregado permite o acompanhamento das variações do perfil refletido da base do prisma ponto a ponto, ou seja, é possível acompanhar toda a dinâmica de evolução do índice de refração da amostra analisada em tempo real. Para confirmação da efetividade da técnica, realizamos medidas da variação do índice de refração de amostras gasosas em função da umidade relativa e da pressão. O sistema demonstrou sensibilidade suficiente para acompanhar mudanças da ordem de 10-5em unidades do índice de refração. / In the present work we propose the use of a refractometric technique based on the determination of the critical angle for the development of a relative humidity sensor and, in the same application scope, a primary vacuum gauge. The proposed technique takes advantage of the phase difference acquired by the parallel and perpendicular components of a, linearly polarized, light beam undergoing internal reflection, to produce an easily detectable intensity minimum in the reflected profile corresponding to the position of the critical angle. We develop a study about the main theoretical aspects involved in the total internal reflection phenomenon, where we perform some simulations aiming to evaluate the variations of the critical angle angular position from changes on the refractive index. The basic set up used in the experiments consist of a HeNe tunable laser, a polarizer, a semi-cylindrical prism with known refractive index made of flint glass type, a analyzer, a linear CCD and a computer, where the information collected by de CCD were treated by means of a data acquisition program developed on the LabVIEWTM platform. The used program allows the point-by-point monitoring of the changes of the profile reflected from the prism base, in other words, one can monitor all the evolution dynamics of the refractive index of the analyzed sample in real time. To confirm the effectiveness of the technique, we perform measurements of changes of the refractive index of gaseous samples as function of the relative humidity and the pressure. The system has shown enough sensitivity to track changes of the order of 10-5 in units of the index of refraction.

Submitted by LILIANE PIMENTEL DA SILVA null (lilinhapsilva@yahoo.com.br) on 2017-02-09T00:15:43Z No. of bitstreams: 1 Dissertação.Liliane.pdf: 7831185 bytes, checksum: 8781451a3c7a43904e560ea59ec0c552 (MD5) / Approved for entry into archive by LUIZA DE MENEZES ROMANETTO (luizamenezes@reitoria.unesp.br) on 2017-02-13T17:30:53Z (GMT) No. of bitstreams: 1 silva_lp_me_prud.pdf: 7831185 bytes, checksum: 8781451a3c7a43904e560ea59ec0c552 (MD5) / Made available in DSpace on 2017-02-13T17:30:53Z (GMT). No. of bitstreams: 1 silva_lp_me_prud.pdf: 7831185 bytes, checksum: 8781451a3c7a43904e560ea59ec0c552 (MD5) Previous issue date: 2017-01-16 / As cidades pequenas desempenham um papel relevante no território nacional, pois são numerosas e apresentam problemas ambientais, mesmo que em menor magnitude quando se compara às grandes cidades. O estudo do clima urbano em cidades de pequeno porte tem crescido, devido à necessidade de se entender a dinâmica climática em locais com menor expressividade territorial e com possibilidade de ter um crescimento urbano mais bem planejado. Nesse sentido, analisou-se o clima urbano de Pirapozinho/SP, município localizado no extremo oeste paulista, pertencente à microrregião de Presidente Prudente/SP. Pirapozinho tem aproximadamente 25 mil habitantes e uma área urbana com construções horizontais e com atividades econômicas diversificadas: comércio, serviços e indústrias. Desta forma, o principal objetivo deste trabalho foi analisar a temperatura e a umidade do ar no espaço urbano e entorno rural próximo para se diagnosticar a geração do clima urbano em Pirapozinho/SP, como resultado da produção espacial da cidade. Para tanto, foram realizadas análises da temperatura e umidade relativa do ar, registradas em pontos fixos e transectos móveis, no intraurbano e rural próximo nos meses de dezembro de 2014 e janeiro de 2015. Para subsidiar a escolha dos pontos e a análise dos resultados foram utilizados mapas de ocupação e uso da terra e das características do relevo. Os registros de temperatura do ar dos transectos móveis realizados no período noturno, no mês de janeiro de 2015, teve como finalidade elaborar um mapa de modelagem da temperatura, a partir do suporte oferecido pelas imagens do satélite LANDSAT 8 (bandas 3, 4 e 5). Além disso, foram elaboradas cartas de temperaturas da superfície, utilizando-se de imagens do satélite LANDSAT 8 (banda 10). Pirapozinho apresentou diferenças térmicas e de umidade relativa do ar entre a área urbana e a área rural, caracterizando as ilhas de calor, em sua maioria, de média magnitude, entre 2° C e 4° C. / Small cities perform a relevant role in the national territory, because they are numerous and present environmental problems, even if to a lesser magnitude when compared to large cities. The study of the urban climate in small cities has grown due to the necessity to understand the climatic dynamics in places with less territorial expressiveness and with the possibility of having a better planned urban growth. In this sense, it hás been analyzed the urban climate of Pirapozinho / SP, a municipality located in the extreme west of São Paulo, belonging to the microregion of Presidente Prudente / SP. In Pirapozinho,there are approximately 25 thousand inhabitants and an urban area with horizontal constructions and diversified economic activities: commerce, services and industries. In this way, the main objective of this work was to analyze the temperature and humidity of the air in the urban space and nearby rural surroundings to diagnose the generation of the urban climate in Pirapozinho / SP, as a result of the spatial production of the city. For that, analyzes of the temperature and relative humidity of the air recorded in fixed points and mobile transects were carried out in the intraurban and near rural areas in the months of December 2014 and January of 2015. In order to subsidize the choice of points and the analysis of the results, occupation maps , land use and relief characteristics were used. The air temperature records of the mobile transects performed in the night period, in January of 2015, had the purpose of elaborating a temperature modeling map, from the support provided by the Landsat 8 satellite images (bands 3, 4 and 5 ). In addition, charts of surface temperatures were made by using images from the Landsat 8 satellite (band 10). Pirapozinho presented thermal and relative humidity differences between the urban area and the rural area, characterizing the islands of heat, mostly of medium magnitude, between 2 ° C and 4 ° C.

Ocean-atmosphere fluxes on the West Florida Shelf (WFS) coastal ocean region are investigated using observations and derived surface fluxes from an array of buoys deployed between 1998 and 2003. The observed annual cycle shows that water column temperatures increase and are stratified when heat flux is positive, and they decrease and are well mixed when it is negative. Water temperature is minimum (maximum) when heat flux switches sign from negative (positive) to positive (negative) in early spring (autumn). Tropical and extra-tropical events help define the seasonal characteristics of the water temperature. Despite considerable daily and synoptic variability in relative humidity, observations on the WFS show that the monthly mean values are nearly constant at about 75%. Winter relative humidity varies from less than 50% to over 100% (supersaturation values of up to 3% are recorded and coincide with fog on shore) as extra-tropical fronts move over the WFS. Sensor distribution shows small spatial variations in relative humidity in the coastal ocean environment that depends on high frequency variability in meteorological conditions and low-frequency variability in oceanic conditions. Comparisons with observations show that standard climatologies are unable to reproduce spatial variability on the WFS, especially in relative humidity and surface heat flux components that are dependent on sea surface temperature. Model experiments show that careful attention must be paid in calculating and applying surface heat fluxes. Observations and models are employed to assess the relative importance of surface fluxes and convergence of heat flux by the ocean circulation in controlling ocean temperature. In spring and autumn, seasonal change in water temperature is mainly controlled by surface heat flux with smaller contributions by ocean convergence, but synoptic scale variability is controlled by both surface heat flux and ocean circulation. Surface fluxes are of primary importance in determining water temperature during the passage of tropical storms or extra-tropical fronts. The coastal ocean temperature balance is fully three-dimensional. Models must be supported by adequate surface heat flux boundary conditions. These require sufficient numbers of in situ measurement points for constraining atmospheric models. The number of observations will depend on the spatial scales of SST variability.

Health care facilities, offices, as well as workshops and other commercial occupancies, require ventilation and air conditioning for thermal comfort and removal of contaminants and other pollutions. A good design of ventilation and air conditioning provides a healthy and comfortable environment for patients, workers, and visitors. The increasing developments of computational fluid dynamics (CFD) in the recent years have opened the possibilities of low-cost yet effective method for improving HVAC systems in design phase, with less experiment required. This work presents numerical simulations of thermal comfort and contaminant removal for two typical working spaces where these factors are critical: a hospital operating room with various configurations of inlet and outlet arrangements, and an office with two cases of air distribution systems: underfloor and overhead, also with alternative cases. The 2-D simulation approach was employed. Temperature, relative humidity, contaminant concentration, thermal sensation, predicted mean vote (PMV), and contaminant removal factor were computed and used for assessing thermal comfort and contaminant removal characteristics of the office room and operating room. The result shows good agreements with experimental data taken from related literature.

Electrostatic charge generation in gas-solid fluidized beds is a significant industrial problem. Associated problems include particle agglomeration and particle wall fouling. In the polymerization industry this may result in "sheets" of fused polymer, due to exothermic reaction causing the melting of the polymer, which can fall off and block the distributor plate disrupting fluidizing gas flow. Additionally, blockage of the catalyst feed or the polymer removal system can take place or the product can become non-uniform. All of these problems require shut-down of the reactor which results in lost production time. While this phenomena has been identified for many years, the mechanisms involved are not well understood, especially wall fouling and the distribution of charge within the bed. Isolation of individual parameters such as hydrodynamics, operating conditions, and material involved is necessary to evaluate how each parameter impacts charge generation during fluidization. In this thesis, the fluidization system consisted of a stainless steel column, two online Faraday cups, and a retractable distributor plate. This system allowed for the simultaneous measurement of charge within different regions of the bed: the entrained fine particles, the particles adhered to the column wall, and the bulk of the bed. Additionally, mass and particle size distributions were measured and images of the layer of particles adhered to the column wall were taken for comparison. This allowed for a charge distribution comparison and evaluation of wall fouling. Three different parameters were investigated: duration of fluidization, column wall material, and relative humidity of fluidizing gas. Fluidization time was studied for 15, 30, 60, 120, 180, and 360 min; relative humidity was investigated for 0%, 20%, 40%, 60%, and 80% relative humidity. Both fluidization time and relative humidity were evaluated at four different fluidization gas velocities, two each in the bubbling and slugging flow regimes. Column wall material was evaluated for a stainless steel and carbon steel column at two gas velocities, one each in the bubbling and slugging flow regimes. Fluidization time was found to influence wall fouling in the bubbling flow regime as the particle layer continued to build as fluidization progressed. In the slugging flow regime, the particle layer developed within 15 minutes of the onset of fluidization. The bubbling flow regime was shown to have a greater capacity for charge generation than the slugging flow regime. This was due to the vigorous mixing in the bubbling flow regime resulting in more particle-particle interactions. Column wall material was shown to influence wall fouling in the slugging flow regime due to the differences in surface roughness of the columns. This was due to the particle-wall contacts resulting in frictional charging which is the predominant charging mechanism in this flow regime. Charge was also impacted in the bubbling flow regime in those particles that were adhered to the column wall. Relative humidity was found to influence wall fouling at the lowest gas velocity tested. However, variations in generation of charge occurred at all fluidization gas velocities tested; the charge-to-mass ratios for the particles adhered to the column wall in the slugging flow regime decreased with high relative humidities. This was due to either the formation of a water film layer on the column wall or instantaneous surface water films on the particles throughout fluidization.

Electrostatic charge generation in gas-solid fluidized beds is a significant industrial problem. Associated problems include particle agglomeration and particle wall fouling. In the polymerization industry this may result in "sheets" of fused polymer, due to exothermic reaction causing the melting of the polymer, which can fall off and block the distributor plate disrupting fluidizing gas flow. Additionally, blockage of the catalyst feed or the polymer removal system can take place or the product can become non-uniform. All of these problems require shut-down of the reactor which results in lost production time. While this phenomena has been identified for many years, the mechanisms involved are not well understood, especially wall fouling and the distribution of charge within the bed. Isolation of individual parameters such as hydrodynamics, operating conditions, and material involved is necessary to evaluate how each parameter impacts charge generation during fluidization. In this thesis, the fluidization system consisted of a stainless steel column, two online Faraday cups, and a retractable distributor plate. This system allowed for the simultaneous measurement of charge within different regions of the bed: the entrained fine particles, the particles adhered to the column wall, and the bulk of the bed. Additionally, mass and particle size distributions were measured and images of the layer of particles adhered to the column wall were taken for comparison. This allowed for a charge distribution comparison and evaluation of wall fouling. Three different parameters were investigated: duration of fluidization, column wall material, and relative humidity of fluidizing gas. Fluidization time was studied for 15, 30, 60, 120, 180, and 360 min; relative humidity was investigated for 0%, 20%, 40%, 60%, and 80% relative humidity. Both fluidization time and relative humidity were evaluated at four different fluidization gas velocities, two each in the bubbling and slugging flow regimes. Column wall material was evaluated for a stainless steel and carbon steel column at two gas velocities, one each in the bubbling and slugging flow regimes. Fluidization time was found to influence wall fouling in the bubbling flow regime as the particle layer continued to build as fluidization progressed. In the slugging flow regime, the particle layer developed within 15 minutes of the onset of fluidization. The bubbling flow regime was shown to have a greater capacity for charge generation than the slugging flow regime. This was due to the vigorous mixing in the bubbling flow regime resulting in more particle-particle interactions. Column wall material was shown to influence wall fouling in the slugging flow regime due to the differences in surface roughness of the columns. This was due to the particle-wall contacts resulting in frictional charging which is the predominant charging mechanism in this flow regime. Charge was also impacted in the bubbling flow regime in those particles that were adhered to the column wall. Relative humidity was found to influence wall fouling at the lowest gas velocity tested. However, variations in generation of charge occurred at all fluidization gas velocities tested; the charge-to-mass ratios for the particles adhered to the column wall in the slugging flow regime decreased with high relative humidities. This was due to either the formation of a water film layer on the column wall or instantaneous surface water films on the particles throughout fluidization.

Excess global elemental sulphur (So) production has resulted in a decrease in its price. As a result, many companies, such as Syncrude Canada Ltd., have resorted to above ground storage alternatives. Geochemical reactions in these above ground blocks produce elevated concentrations of H2SO4 (acid). This acid can have potentially deleterious effects on the environment. As such, these blocks will require long-term (500 years) monitoring and maintenance. Presently the So is removed from the product stream, piped in a molten state, and poured over a low permeability liner in thin lifts. As the So cools and undergoes crystal structure change it fractures, creating preferential flow passages which are potentially highly conductive. An understanding of the liquid conductivity (Kl) of the block and knowledge regarding the spatial and temporal distribution of acid (H2SO4) within these blocks is required. In this thesis, gas pumping tests were conducted on an above ground block to determine the gas flow rates within the block and to indirectly determine the Kl of the block. Measurements of the relative humidity (RH) in the block were used to observe changes in stored acid concentrations with time and location. The results of the gas conductivity (Kg) testing showed that the block is anisotropic and is highly conductive in both the horizontal and vertical directions. Cross hole tests appeared to produce the most representative estimates of Kg due to the negation of turbulence that arises in the vicinity of the borehole. The choice of gas used in the analysis had negligible effect on the resulting Kl in contrast to choice of liquid, which resulted in larger variations in Kl. The Kl was a maximum when the liquid was pure water and decreased with increasing acid strength. The geometric mean of the resulting cross hole Kl values was 2 x 10-3 m s-1 (pure water). RH measurements were observed to fluctuate with depth and increased following precipitation. The resulting minimum pH observed within the block occurred at depths of 3 and 7 meters below the surface of the So block and increased with depth. The arithmetic mean pH value based on the daily averaged RH measurements was -1.7.

Factors governing the efficiency of convective moistening in the tropical upper troposphere between 15