In-situ polymerization is one of the most efficient methods for production of polymer clay nanocomposites. In-situ polymerization of olefins using coordination catalysts is a type of heterogeneous polymerization. In order to achieve acceptable clay nanolayer dispersion in the polyolefin matrix, the clay layer exfoliation and particle break up during the polymerization are essential requirements. A literature review on polyolefin/clay nanocomposite is given in Chapter 2. In Chapter 3, we present a new mathematical model, which is as an extension of the multigrain model (MGM), to describe the intercalative polymerization and expansion of clay interlayer spaces during polymerization using clay-supported metallocenes. The results from the model show that, under the studied conditions, mass transfer is not a strong factor controlling clay exfoliation and particle break up. If the polymerization active sites are supported uniformly on all clay surfaces, effective exfoliation will be achieved after a relative short polymerization time. In practice, obtaining good dispersion of clay nanolayers with uniform properties requires that the active sites be exclusively located on the clay nanolayer surfaces, and not extracted by the solvent to form a homogeneous solution. Factors favouring active site extraction would result in nanocomposites with poor properties. In addition, high polymerization activities, stable polymerization runs, and ease of supporting are other criteria for a successful in-situ polymerization. For this purpose we established a catalyst supporting method by which most of these requirements were met. In this method, the water content on the clay surface, which is considered as poison for the metallocene catalyst, was used to produce MAO upon reaction with trimethylaluminum (TMA). Using this method, polymerization was highly active in absence of MAO cocatalyst, knowing that MAO cocatalyst promotes active site extraction from the clay surface and results in poor powder morphology. Chapter 4 describes the development of this supporting methodology. Chapter 4 also investigates the effect of the organic modification type existing on the clay surface on the success of catalyst supporting and in-situ polymerization. We found that using the proposed supporting procedure, only tertiary ammonium type modification enhanced the in-situ polymerization, whereas the quaternary ammonium worsened the catalyst supporting efficiency and led to catalyst with poor or no polymerization activity. It is suggested that, in addition to enhancing clay surface-organic solvent compatibility (which facilitates catalyst supporting), the tertiary ammonium cation reacts with the in-situ produced MAO and increases the stability of the cocatalyst bonded to the clay surface. The effect of different polymerization conditions on the polymerization behavior and nanocomposite structural properties, such as catalyst loading during supporting, polymerization temperature and triisobutylaluminum (TIBA) concentration, were studied in Chapter 5. It was found that TIBA acts merely as scavenger. High polymerization activities were obtained with low Al/Zr ratios (Al from TIBA) and increased Al concentration decreased the polymerization activity and also the quality of powder morphology. Catalyst loading in the supporting step showed to have an important role in determining the final properties. The clay particles with higher catalyst loading resulted in better exfoliation and powder morphologies The effect of solvent type during catalyst supporting and polymerization was studied in Chapter 6. It was shown that catalyst supporting in n-hexane resulted in polymerizations with higher activities and polymers with higher molecular weight were produced. Polymerization with catalyst supported in hexane showed different ethylene uptake profiles, suggesting different mechanism of exfoliation. It is suggested that using this catalyst, the clay is mostly exfoliated before polymerization started. Similar to the original clay, the catalyst supporting efficiency on the organically modified clay was close to 100 percent. However, comparing the polymerization activities of these catalysts to those that were supported directly in the reactor just before the polymerization (in-reactor, or in-situ, supported catalysts) shows that a considerable fraction of the active sites are deactivated during the prolonged contact between catalyst and clay support surface. In Chapter 5, it was shown that the in-reactor supported catalyst had considerably higher polymerization activities, up to 40 percent of that of the homogeneous catalyst. Nanocomposites made with in-reactor supported catalysts had powder morphology and nanaolayer dispersion comparable to those made with clay-supported catalysts.

In-situ polymerization is one of the most efficient methods for production of polymer clay nanocomposites. In-situ polymerization of olefins using coordination catalysts is a type of heterogeneous polymerization. In order to achieve acceptable clay nanolayer dispersion in the polyolefin matrix, the clay layer exfoliation and particle break up during the polymerization are essential requirements. A literature review on polyolefin/clay nanocomposite is given in Chapter 2. In Chapter 3, we present a new mathematical model, which is as an extension of the multigrain model (MGM), to describe the intercalative polymerization and expansion of clay interlayer spaces during polymerization using clay-supported metallocenes. The results from the model show that, under the studied conditions, mass transfer is not a strong factor controlling clay exfoliation and particle break up. If the polymerization active sites are supported uniformly on all clay surfaces, effective exfoliation will be achieved after a relative short polymerization time. In practice, obtaining good dispersion of clay nanolayers with uniform properties requires that the active sites be exclusively located on the clay nanolayer surfaces, and not extracted by the solvent to form a homogeneous solution. Factors favouring active site extraction would result in nanocomposites with poor properties. In addition, high polymerization activities, stable polymerization runs, and ease of supporting are other criteria for a successful in-situ polymerization. For this purpose we established a catalyst supporting method by which most of these requirements were met. In this method, the water content on the clay surface, which is considered as poison for the metallocene catalyst, was used to produce MAO upon reaction with trimethylaluminum (TMA). Using this method, polymerization was highly active in absence of MAO cocatalyst, knowing that MAO cocatalyst promotes active site extraction from the clay surface and results in poor powder morphology. Chapter 4 describes the development of this supporting methodology. Chapter 4 also investigates the effect of the organic modification type existing on the clay surface on the success of catalyst supporting and in-situ polymerization. We found that using the proposed supporting procedure, only tertiary ammonium type modification enhanced the in-situ polymerization, whereas the quaternary ammonium worsened the catalyst supporting efficiency and led to catalyst with poor or no polymerization activity. It is suggested that, in addition to enhancing clay surface-organic solvent compatibility (which facilitates catalyst supporting), the tertiary ammonium cation reacts with the in-situ produced MAO and increases the stability of the cocatalyst bonded to the clay surface. The effect of different polymerization conditions on the polymerization behavior and nanocomposite structural properties, such as catalyst loading during supporting, polymerization temperature and triisobutylaluminum (TIBA) concentration, were studied in Chapter 5. It was found that TIBA acts merely as scavenger. High polymerization activities were obtained with low Al/Zr ratios (Al from TIBA) and increased Al concentration decreased the polymerization activity and also the quality of powder morphology. Catalyst loading in the supporting step showed to have an important role in determining the final properties. The clay particles with higher catalyst loading resulted in better exfoliation and powder morphologies The effect of solvent type during catalyst supporting and polymerization was studied in Chapter 6. It was shown that catalyst supporting in n-hexane resulted in polymerizations with higher activities and polymers with higher molecular weight were produced. Polymerization with catalyst supported in hexane showed different ethylene uptake profiles, suggesting different mechanism of exfoliation. It is suggested that using this catalyst, the clay is mostly exfoliated before polymerization started. Similar to the original clay, the catalyst supporting efficiency on the organically modified clay was close to 100 percent. However, comparing the polymerization activities of these catalysts to those that were supported directly in the reactor just before the polymerization (in-reactor, or in-situ, supported catalysts) shows that a considerable fraction of the active sites are deactivated during the prolonged contact between catalyst and clay support surface. In Chapter 5, it was shown that the in-reactor supported catalyst had considerably higher polymerization activities, up to 40 percent of that of the homogeneous catalyst. Nanocomposites made with in-reactor supported catalysts had powder morphology and nanaolayer dispersion comparable to those made with clay-supported catalysts.

Digestion of starch in humans starts in the mouth and progresses to the small intestine. Structures from salivary and pancreatic amylases hydrolysis can impact subsequent steps of digestion at the mucosa of the small intestine. However, structures of the starch digestion products along the gut from the mouth to the small intestines – products that impact glucose homeostasis are not well understood. This thesis focuses on the luminal step of starch digestion, i.e. impact of salivary and pancreatic amylase on the structure of hydrolysis products obtained from cooked starches from different botanical sources. Normal corn (NCS), wheat (NWS) and potato (NPS) starches were cooked at 1:0.7 (T0.7) or 1:2 (T2) starch:water ratios. Cooked starches were subjected to salivary amylase at conditions mimicking oral digestion. The composition of the hydrolysates was characterised by gel-permeation chromatography. Extent of hydrolysis was lower at T0.7 compared to T2, but the amount of carbohydrates in different fractions and the molecular weight profiles within each treatment were not different between starches from different botanical sources. However, debranching of the hydrolysates revealed structural differences in extent of amylose hydrolysis and amount and profile of lower molecular weight fractions between different starches. Cooked starches were also subjected to salivary and pancreatic amylases hydrolysis. Extent of 20 min hydrolysis was lower at T0.7 compared to T2 for all the starches. Oligosaccharide composition of 120 min hydrolysates differed in amounts of DP 2, 3, 5, 6 and 7 between processing treatments and starches. NCS (T2) was treated with saliva from six participants at equal activity. Salivary amylase activities ranged from 470 x 103 to 118 x 103 U/mL among the participants. While saliva from participant 2 (high amylase activity) greatly reduced the high molecular weight fraction, saliva from participant 6 (low amylase activity) more extensively hydrolysed the starch to small molecular weight fractions of oligosaccharides. These results show that different starch hydrolysates are produced during oral digestion by saliva from different individuals and are also different based on cooking condition or botanical source of starch. Further research is therefore needed to understand how these hydrolysate structures, impact glucose homeostasis.

Gelfill (GF) is made of tailings, water, binder and chemical additives (Fillset, sodium silicate gel). The components of GF are combined and mixed on the surface and transported (by gravity and/or pumping) to the underground mine workings, where the GF can be used for both underground mine support and tailings storage. Thermal (T), hydraulic (H), and mechanical (M) properties are important performance criteria of GF. The understanding of these engineering properties and their evolution with time are still limited due to the fact that GF is a new cemented backfill material. In this thesis, the evolution of the thermal, hydraulic, mechanical, and microstructural properties of small GF samples are determined. Various binder contents of Portland cement type I (PCI) are used. The GF is cured for 3, 7, 28, 90, and 120 days. It is found that the thermal, hydraulic and mechanical properties are time-dependent or affected by the degree of binder hydration index. Furthermore, a relationship is found between the compressive strength and the saturated hydraulic conductivity of the GF samples. The unsaturated hydraulic properties of GF samples have also been investigated. The outcomes show that unsaturated hydraulic conductivity is influenced by the degree of binder hydration index and binder content, especially at low suction ranges. Simple functions are proposed to predict the evolution of air-entry values (AEVs), residual water content, and fitting parameters from the van Genuchten model with the degree of hydration index (α). Furthermore, two columns are built to simulate the coupled thermo-hydro-mechanical (THM) behaviour of GF under drained and undrained conditions. The obtained results from the GF columns are compared with the small samples. It is observed that the mechanical properties, hydraulic properties (suction and water content), and temperature development are strongly coupled. The magnitude of these THM coupling factors is affected by the size of the GF. The findings also show that the mechanical, hydraulic and thermal properties of the GF columns are different from samples cured in plastic moulds.

L'étude présentée dans cette thèse porte sur une analyse expérimentale des propriétés physiques (densités, porosité, granulométrie) et hydrodynamiques (isotherme de désorption, courbe caractéristique sol-eau, perméabilité à saturation) d'un sol type aride du Burkina Faso et une simulation numérique des transferts d'eau. La modélisation des transferts est abordée par une approche thermodynamique qui constitue un cadre général pour décrire à la fois l'état de l'eau dans le sol et les mécanismes de transferts mis en jeu : filtration de la phase liquide, diffusion de la vapeur d'eau, changement de phase liquide-vapeur. Des essais expérimentaux de transferts d'eau dans des colonnes de sol hermétiquement fermées et placées dans une enceinte régulée en température, ont permis d'établir l'évolution des profils de teneur en eau au cours du temps. La configuration expérimentale est choisie de sorte que seule la filtration de la phase liquide de l'eau dans le sol soit prépondérante. Les profils expérimentaux ont servi à l'estimation par approche inverse de la conductivité hydraulique dans les faibles teneurs en eau. La prise en compte des écoulements par films dans la modélisation du coefficient de perméabilité relative corrige les insuffisances des modèles capillaires. Les coefficients de changement de phase proche et loin de l'équilibre modélisés à partir de résultats expérimentaux permettent la mise en évidence du non-équilibre liquide/gaz dans les transferts aux faibles teneurs en eau. Il ressort que le non-équilibre dans les transferts aux faibles teneurs en eau est plus marqué avec le modèle capillaire avec un front de séchage plus franc à la surface. La prise en compte des écoulements par films prolonge la filtration de la phase liquide de l'eau jusqu'à l'état hygroscopique du sol avec un flux d'eau liquide maintenu à la surface du sol jusqu'à des temps plus longs. / The study presented in this thesis focuses on an experimental analysis of physical properties (densities, porosity, particle size distribution) and hydrodynamic properties (desorption isotherm, soil-water characteristic curve, saturated permeability) of an arid soil from Burkina Faso and numerical simulation of water transfers. The transfer modelling is addressed through thermodynamic approach which provides a general framework to describe both the water state in the soil and the transport mechanisms: filtration of liquid phase, water vapor diffusion, liquid/vapor phase change. Experimental attempts of water transfer in soil columns, sealed and placed into a controlled temperature chamber, have established the evolution of water content profiles over time. The experimental configuration is chosen so that only the filtration of water liquid phase is taken into account. These experimental profiles were used to estimate, by inverse approach, the unsaturated hydraulic conductivity at low water contents. Consideration of film flows in the relative permeability modelling corrects the shortcomings of capillary bundle models used to describe water flow from saturation to oven-dryness. The coefficients of phase change near and far from equilibrium modeled from experimental results prove non-equilibrium liquid/gas existence. It appears that the liquid/gas non-equilibrium at low water content is more pronounced with the capillary model with a frank drying front at the soil surface. Consideration of film flows extends liquid phase filtration into the soil until the hygroscopic state with a liquid water flux maintained at the soil surface for longer times.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Susceptibility to soil degradation is a function of disturbance intensity and structure resistance, which is usually described by mesoscale properties. However, soil mechanical strength in the microscale (micromechanical) evaluated by rheology is not well known. The objective was to evaluate the micromechanical resistance of soils of Rio Grande do Sul through amplitude sweep tests under oscillatory shear, to know the variables that influence this resistance and to evaluate its relationship with physical and mechanical properties in mesoscale. Surface and subsurface horizons of eight soils, Oxisol (4), Ultisol (2), Alfisol (1) and Vertisol (1), were characterized for particle size, mineralogy, chemical, physical and mechanical in micro and mesoscale. The micromechanical resistance of soils was evaluated by rheological curves and parameters, and the influence of water content on rheological parameters was evaluated by regression analysis. The influence of soil composition on rheological parameters and the relationship between rheological parameters and physical and mechanical properties were evaluated by correlation analysis and principal component analysis. There was great variation between soils and horizons according its constitution of particle size, mineralogy and chemistry, where sand, clay, total carbon and presence of 2:1 clay minerals were the most influential factors on rheological behavior of the soils. Soil matric potential also had a strong influence on micromechanics resistance of soils. There were correlations of rheological parameters with physical properties (bulk density and soil porosity), but few correlations with mesomechanical properties (uniaxial compressibility and direct shear). The higher silt and clay content increased the microstructural resistance of the soil, where higher sand content decreased this resistance. The predominance of smectite in clay fraction increased the microstructural elasticity; the increased of kaolinite decreased the elasticity and the increased of iron oxides raised the microstructural stiffness (shear stress) of the soils. Increased water pressure increased micromechanical resistance of most soils due to meniscus force, occurring reduction in micromechanics stiffness at 10 kPa pressure due to presence of pseudosand associated with low bulk density. The increase of carbon content increased soil elasticity, but decreased soil rigidity; and cations content correlated only indirectly with rheological parameters. The larger correlation between rheological parameters and physical properties is probably due to aggregation factors being the same in both scales, such as particle size, mineralogy and their interactions. On the other hand, the low relation of soil mechanical resistance in micro and mesoscale seem influenced by different factors related to soil composition and structure. / A suscetibilidade do solo à degradação é função da intensidade da perturbação e da resistência da estrutura, a qual é normalmente descrita por propriedades em mesoescala. Entretanto, a resistência mecânica do solo em microescala (micromecânica) avaliada por meio da reologia é pouco conhecida. O objetivo foi avaliar a resistência micromecânica de solos do Rio Grande do Sul com o uso de testes de varredura de amplitude por cisalhamento oscilatório, conhecer as variáveis que influenciam essa resistência e avaliar sua relação com propriedades físicas e mecânicas em mesoescala. Os horizontes superficial e subsuperficial de oito solos das ordens Latossolo (4), Argissolo (2), Planossolo (1) e Vertissolo (1) foram caracterizados quanto à granulometria, mineralogia, propriedades químicas, físicas e mecânicas em micro e mesoescala. A resistência micromecânica dos solos foi avaliada por curvas e parâmetros reológicos e a influência do conteúdo de água sobre parâmetros reológicos foi avaliada por análise de regressão. A influência da composição do solo nos parâmetros reológicos e a relação entre parâmetros reológicos e propriedades físicas e mesomecânicas foram avaliadas por análise de correlação e análise de componentes principais. Houve grande variação entre os solos e horizontes quanto à sua constituição granulométrica, mineralógica e química, sendo areia, argila, carbono e presença de argilominerais 2:1 os fatores que mais influenciaram o comportamento reológico dos solos. A tensão de água também teve forte influência na resistência micromecânica dos solos. Foram verificadas correlações de parâmetros reológicos com propriedades físicas (densidade e porosidade do solo), mas poucas correlações com propriedades mesomecânicas (compressibilidade uniaxial e cisalhamento direto). O aumento dos teores de silte e argila aumentou a resistência micromecânica do solo, enquanto maiores teores de areia diminuíram essa resistência. O predomínio de esmectita na fração argila aumentou a elasticidade microestrutural; a caulinita diminuiu a elasticidade; e o aumento de óxidos de ferro aumentou a rigidez (tensão de cisalhamento) microestrutural dos solos. O aumento da drenagem aumentou a resistência micromecânica da maioria dos solos devido ao aumento das forças de meniscos, ocorrendo redução da rigidez micromecânica na tensão de água de 10 kPa em horizontes com presença de pseudoareia associada com baixa densidade do solo. O incremento dos teores de carbono aumentou a elasticidade do solo, mas diminuiu sua rigidez; e os teores de cátions correlacionaram-se indiretamente com parâmetros reológicos. A maior relação entre parâmetros reológicos e propriedades físicas decorre, provavelmente, dos fatores de agregação serem os mesmos em ambas as escalas, como a granulometria, a mineralogia e suas interações. Por outro lado, a relação da resistência mecânica do solo em micro e mesoescala foi pequena, pois parecem influenciadas por diferentes fatores relacionados à composição e estrutura do solo.

A reflectometria no domínio do tempo permite estimar o teor de umidade de um meio através da sua correlação com a constante dielétrica. Uma sonda helicoidal TDR, que pode ser cravada em conjunto outros ensaios de penetração in situ para a estimativa do teor de umidade em diversas profundidades, tem aplicação interessante para a investigação geotécnica do subsolo. No presente trabalho, uma sonda TDR foi adaptada e utilizada em conjunto ao ensaio CPT para caracterização de um perfil de solo arenoso não saturado que ocorre na região de Bauru (SP). A calibração dessa sonda foi feita em laboratório especificamente para esse solo. As equações de calibração que mostraram os melhores resultados foram definidas correlacionando a constante dielétrica, condutividade elétrica aparente e a massa específica seca com o teor de umidade. Com o intuito de melhorar a acurácia na determinação do teor de umidade em campo e eliminar possíveis interferências no registro da onda eletromagnética, foram efetuadas modificações em algumas características do projeto original dessa sonda. Tais modificações consistiram em separar os eletrodos condutores e as partes metálicas da sonda, e eliminar o cabo coaxial de extensão, conectando a sonda diretamente a um cabo coaxial de 12 m de comprimento. Tais mudanças levaram a uma melhoria significativa na determinação do perfil de teor de umidade do local estudado. Os valores de teor de umidade de campo determinados usando o TDR ao longo de 8 m de profundidade foram comparados com os valores de referência obtidos de amostras deformadas retiradas com trado mecânico. O erro médio na estimativa do perfil de teor de umidade gravimétrico utilizando a sonda TDR helicoidal foi de 1.61%, na última campanha de ensaios realizados. Os resultados dessa pesquisa indicam que esta ferramenta é adequada para estimar do perfil de teor de umidade para uso em conjunto com o ensaio CPT. / The time domain reflectometry allows estimating the moisture content of a medium by means of its correlation with the dielectric constant. A coil TDR probe, which can be driven into the ground together with others in situ penetration tests, can be used to estimate the moisture content at different depths. It is an interesting approach for geotechnical site characterization. In this work, a coil TDR probe was adapted and used in combination with the CPT test for the site characterization of an unsaturated sandy soil profile which occurs in the region of Bauru (SP). The probe calibration was performed in laboratory specifically for that soil. The calibration equation, which presented the best results, were defined correlating the dielectric constant, electrical conductivity and dry density with the moisture content. In order to improve the accuracy for determining the water content in the field and to eliminate possible interference on the electromagnetic wave registration, modifications were made in some characteristics of the original design of this probe. Such modifications consisted in separating the conductive electrodes from the metal parts of the probe, and eliminating the coaxial extension cable, connecting the probe directly to a coaxial cable 12 m long. Such changes have led to a significant improvement in the determination of the moisture content profile of the studied site. The moisture content values determined in situ by using the TDR along 8 m depth were compared with reference values obtained from disturbed soil samples collected using mechanical augers. The root mean square error of the gravimetric water content profile using the TDR coil probe was 1.61% in the last test campaign. The results of this research indicate that this tool is suitable to estimate the gravimetric moisture content together with the CPT test.

Made available in DSpace on 2016-12-23T14:37:33Z (GMT). No. of bitstreams: 1 Dissertacao Maria Christina Junger.pdf: 2116125 bytes, checksum: a838fb12301a6580f6dc47358feed2c7 (MD5) Previous issue date: 2006-02-24 / The objective of this work was to evaluate the influence of the soil humidity in the field capacity in the tensions of 0,006 MPa (FC1), 0,010 MPa (FC2) and 0,033 MPa (FC3) and of different levels of water deficits (WD 0%, WD 33% and WD 67%) in the initial growth of the coffee plant conilon and in the leaf water potential measured in the anti-morning, in a Red-Yellow Oxisol (OR) and Red-Yellow Ultisol (URY). The experiment was let vegetation home, being cultivated the plants in vases of 12 liters during 255 days. The adopted experimental design was randomized entirely, mounted in outline of subdivided portions, with three repetitions for each soil. The growth evaluations were achieved each 60 days and the analyzed data by the surface technique of answering. The tenor of soil humidity in the field capacity varies with the adopted tension in its determination. The growth of the coffee plant conilon in WD 0% was higher to the obtained in the water deficits of 33% and 67% of OR and URY. The largest growth of the culture was observed in FC2 of OR and in FC1 of URY. The smallest growth was obtained in the water deficits of the certain field capacity in the tension of 0,033 MPa (FC3) of OR and URY, what unfeasible its adoption in the estimate of the irrigation sheet, being used the camera of pressure of Richards. The x leaf water potential anti-morning (Ψam) showed to be a good indicator of the degree of hydration of the plants. The largest hydration to foliate was observed in WD 0%, being in CC2 for OR (Ψam = -0,17 MPa), being the water kept by the soil to a potential matric (Ψm) of -0,010 MPa and in CC1 for URY (Ψam = -0,33 MPa), which Ψm was the -0,006 MPa. To smallest hydration happened in WD 67% and in the FC3, also for OR (Ψam = -0,68 MPa) as for URY (Ψam = -1,3 MPa), being the water kept of Ψm of -0,20 MPa, for both soils. In WD 33% and WD 67% in the levels of the capacity of field of OR and URY, they were verified a reduction in the values leaf area, height and diameter of the stem of the plants. The accumulation of total dry matter and leaf water potential anti-morning observed in OR were superior to the of URY, in all of the levels of the field capacity and water deficits, resulting in the larger initial growth of the coffee plant conilon in this soil. / O objetivo deste trabalho foi avaliar a influência da umidade do solo na capacidade de campo determinada nas tensões de 0,006 MPa (CC1), 0,010 MPa (CC2) e 0,033 MPa (CC3) e de diferentes níveis de déficits hídricos (DH 0%, DH 33% e DH 67%), no crescimento inicial do cafeeiro conilon e no potencial hídrico foliar medido na antemanhã, em um Latossolo Vermelho-Amarelo (LV) e Argissolo Vermelho-Amarelo (PVA). O experimento foi conduzido em casa de vegetação, cultivando-se as plantas em vasos de 12 litros durante 255 dias. O delineamento experimental adotado foi inteiramente casualizado, distribuído em esquema de parcelas subdivididas, com três repetições para cada solo. As avaliações de crescimento foram realizadas a cada 60 dias e os dados analisados pela técnica de superfície de resposta. O teor de umidade do solo na capacidade de campo varia com a tensão adotada em sua determinação. O crescimento do cafeeiro conilon em DH 0% foi superior aos obtidos nos déficits hídricos de 33% e 67% do LV e do PVA. O maior crescimento da cultura foi observado na CC2 do LV e na CC1 do PVA. O menor crescimento foi obtido nos déficits hídricos da capacidade de campo determinada na tensão de 0,003 MPa (CC3) do LV e do PVA, o que inviabiliza a sua viii adoção na estimativa da lâmina de irrigação, utilizando-se a câmara de pressão de Richards. O potencial hídrico foliar antemanhã (Ψam) mostrou-se bom indicador do grau de hidratação das plantas. A maior hidratação foliar foi observada em DH 0%, sendo para o LV na CC2 (Ψam= -0,17 MPa), estando a água retida pelo solo a um potencial matricial (Ψm) de -0,010 MPa, e para o PVA na CC1 (Ψam = -0,33 MPa), cujo Ψm foi de -0,006 MPa. A menor hidratação ocorreu em DH 67% na CC3 tanto para o LV (Ψam = -0,68 MPa) como para o PVA (Ψam = -1,30 MPa), estando a água retida a um Ψm de -0,20 MPa, para ambos os solos. Em DH 33% e DH 67% nos níveis de capacidade de campo do LV e do PVA, foram verificadas reduções nos valores da área foliar, altura e diâmetro do caule das plantas. O acúmulo de matéria seca total e potencial hídrico foliar antemanhã observados no LV foram superiores aos do PVA, em todos os níveis de capacidade de campo e déficits hídricos, resultando em maior crescimento inicial do cafeeiro conilon, neste solo.

Submitted by Gabriela Lopes (gmachadolopesufpel@gmail.com) on 2018-08-13T17:46:02Z No. of bitstreams: 1 Cópia revisada ledemar-Luciano PDF.pdf: 1720131 bytes, checksum: 693af5179fe3089038ef47e6746002c4 (MD5) / Approved for entry into archive by Aline Batista (alinehb.ufpel@gmail.com) on 2018-08-16T18:55:29Z (GMT) No. of bitstreams: 1 Cópia revisada ledemar-Luciano PDF.pdf: 1720131 bytes, checksum: 693af5179fe3089038ef47e6746002c4 (MD5) / Made available in DSpace on 2018-08-16T18:55:29Z (GMT). No. of bitstreams: 1 Cópia revisada ledemar-Luciano PDF.pdf: 1720131 bytes, checksum: 693af5179fe3089038ef47e6746002c4 (MD5) Previous issue date: 2017-09-29 / A produção de pêssego ocupa destaque entre as frutíferas de clima temperado no Brasil, sendo o Estado do Rio Grande do Sul responsável por 65 % da produção. Para obter elevada produtividade com frutos de qualidade, o pessegueiro requer adequado suprimento de água durante a primavera e o verão. Neste período, é frequente a ocorrência de déficit hídrico e a irrigação pode promover aumento de rendimento e qualidade dos frutos. Os objetivos deste trabalho foram: avaliar a resposta do pessegueiro à irrigação, quanto ao estado hídrico das plantas e a produtividade e qualidade dos frutos; determinar o manejo de água no solo mais adequado para a cultura do pessegueiro; e avaliar a influência da textura do solo no manejo da água. O estudo foi realizado em um pomar de pessegueiro comercial, cv Esmeralda, localizado no município de Morro Redondo - RS, durante as safras 2014/15, 2015/16 e 2016/17. Foram demarcadas duas áreas homogêneas em função da classe textural do solo, sendo classificadas como Franco Arenosa e Franco Argilo Arenosa. As plantas foram irrigadas por sistema de irrigação localizada por gotejamento. Os resultados mostraram que: a irrigação na fase de crescimento de fruto não influenciou a produtividade nem o tamanho dos frutos; a irrigação na fase de pós-colheita aumentou o crescimento vegetativo na safra seguinte mas não afetou a produção de frutos; os pessegueiros da área do pomar com solo franco arenoso produziram frutos maiores do que os da área com solo franco argilo arenoso; o manejo da irrigação baseado no potencial de água no ramo gera maior consumo de água, seguido pelo manejo baseado no teor de água no solo e, por último, o manejo baseado no clima / The production of peach stands out among the fruits of temperate climate in Brazil, being the State of Rio Grande do Sul (RS) responsible for 65% of the production. To achieve high productivity with quality fruits, the peach tree requires adequate water supply during spring and summer. During period, water deficit is frequent and irrigation can promote yield increase and fruit quality. The objectives of this study were to evaluate the peach response to irrigation, as the water status of plants and productivity and fruit quality; to determine the soil water management most appropriate for the peach tree; and to evaluate the influence of soil texture on water management. The study was carried out in a commercial peach orchard, cv Esmeralda, located in the municipality of Morro Redondo - RS, during the harvests of 2014/15, 2015/16 and 2016/17. Two homogeneous areas were demarcated according to the textural class of the soil, being classified as Sandy Loam and Sandy Clay Loam. The plants were irrigated by a drip irrigation system. The results showed that: irrigation in the fruit growth phase did not influence fruit productivity nor fruit size; post-harvest irrigation increased vegetative growth in the next crop but did not affect fruit production; the peach orchard area with sandy loam soil produced larger fruit than the area with sandy loam clay soil; the management of irrigation based on the water potential in the branch generates greater water consumption, followed by management based on the water content in the soil and, finally, the management based on the climate.

Made available in DSpace on 2014-07-29T15:18:22Z (GMT). No. of bitstreams: 1 Dissertacao Arlam Carneiro Silva Junior.pdf: 5610626 bytes, checksum: fe6e7853bf1c86d2facd82a4cb682131 (MD5) Previous issue date: 2011-03-03 / The evaluation of soil-atmosphere interaction is crucial in several examples of geotechnical works as compaction operations, construction and operation of dams and slope stability. Generally, in these examples, the soils are in unsaturated state. The main objective of this study is to assess and refine the mechanistic approach to predict the changing conditions of suction and moisture of a soil profile unsaturated. Three methods for predicting soil-water characteristic curve were evaluated, and a new method was proposed. The prediction methods, examined in this study, are based on particle size and other index properties. Were considered the soil of the experimental field of Furnas in Aparecida de Goiania (Goiás - Brazil), the soil of the experimental field of the University of Brasilia and soils of temperate climate. Good results were obtained from the prediction methods used. Were monitored for six months, the water content, suction, groundwater and atmospheric conditions of the experimental field of Furnas. The water content was obtained by removal of soil samples and suction was obtained by two measuring methods: filter paper and tensiometer. A device for installation and under the filter paper in the field was developed. The method of the paper filter had good results of total suction and the use of a tensiometer allowed measurements of a limited range of matric suction. Water content and suction predictions were made for the experimental field of Furnas from numerical analysis. It considered soil-water characteristic curves experimental and provided in numerical analysis. It have found most difficult to predict suction and moisture for the shallowest depth analyzed. / A avaliação da interação solo-atmosfera tem um papel fundamental em diversos exemplos de obras geotécnicas como operações de compactação, construção e operação de barragens e estabilidade de taludes. E geralmente, nestes exemplos, os solos se encontram no estado não saturado. Este trabalho tem como objetivo principal avaliar e aperfeiçoar a abordagem mecanística de previsão das variações das condições de sucção e umidade de um perfil de solo não saturado. Foram aplicados e avaliados três métodos de previsão de curva característica solo-água, e um novo método foi proposto. Os métodos de previsão, analisados nesta pesquisa, são baseados na granulometria do material e outras propriedades índice. Foram considerados para previsão os solos do campo experimental de Furnas em Aparecida de Goiânia (Goiás), do campo experimental da Universidade de Brasília e três solos de clima temperado do Canadá. Foram obtidos bons resultados de previsão a partir dos métodos utilizados. Foram monitorados, durante seis meses, as condições de umidade, sucção, lençol freático e condições atmosféricas do campo experimental de Furnas. A umidade foi obtida através da retirada de amostras do solo e a sucção foi obtida por dois métodos de medição: papel filtro e tensiômetro. Um dispositivo para instalação e abrigo do papel filtro no campo foi desenvolvido. A aplicação do método do papel no campo teve bons resultados de sucção total e a utilização do tensiômetro permitiu a medição de uma limitada faixa de sucção matricial. Foram ainda realizadas previsões de sucção e umidade para o campo experimental de Furnas a partir de análises numéricas. Curvas características solo-água experimentais e previstas foram consideradas nas análises numéricas. Foram encontradas maiores dificuldades para prever sucção e umidade para o metro mais raso analisado.