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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Mise au point d'une méthodologie pour formuler de nouveaux bétons auto-plaçants légers et durables / Design method to formulate sustainable self consolidating lightweight aggregates concrete

Bello, Latifou 29 September 2014 (has links)
Les bétons auto-plaçants (BAP) sont des bétons spéciaux, très maniables, homogènes et stables qui se mettent en place sous le seul effet de la gravité. Grâce à leurs nombreux avantages, les bétons auto-plaçants (BAP) sont aujourd'hui considérés comme étant l'une des innovations les plus marquantes des deux dernières décennies dans le domaine du béton. Plus de 50 % des produits à démoulage différé sont réalisés en BAP. Parallèlement, les bétons légers sont maintenant intégrés dans le contexte normatif et leur utilisation dans l'industrie est croissante du fait notamment de la nouvelle réglementation thermique pour les bâtiments. Ce contexte ouvre la voie aux bétons auto-plaçants légers (BAPL) dont l'utilisation constitue une solution innovante pour répondre encore mieux, aux problématiques de légèreté, d'efficacité énergétique des bâtiments et de productivité. Cependant, la différence de densité entre les granulats légers et la pâte d'une part et le pouvoir absorbant des granulats légers d'autre part, compliquent davantage la formulation et la production des bétons auto-plaçants légers. De plus, les méthodes existantes qui sont pour la plupart empruntées aux méthodes de formulation de BAP traditionnels restent empiriques.Cette thèse vise donc la mise au point d'une méthode de formulation plus rationnelle pour composer des bétons auto-plaçants légers et durables. Cette approche de formation des BAPL est construite autour d'un ensemble de données cohérent dont l'indice de serrage de l'empilement et sur la quantification expérimentale des phénomènes tels que l'absorption dans la pâte de ciment et la ségrégation. A partir de cette méthode, différentes gammes de BAPL sont proposées pour répondent aux critères du cahier des charges en termes de masse volumique réelle sèche et de résistance à la compression. Sa mise en œuvre a permis de simuler et de réaliser des formules de bétons auto-plaçants légers de sable normal (BAPLSN) de classes d'étalement allant de SF1 à SF3, de classes de masse volumique D1.8 et D2.0 et de classes de résistance allant de LC35/38 à LC50/55. Elle a également permis d'explorer les bétons auto-plaçants légers de sable léger (BAPLSL) qui peuvent constituer une solution innovante pour l'industrie du béton dans le contexte de la nouvelle réglementation thermique pour les bâtiments. / Self compacting concrete (SCC) is generally known as the concrete capable of filling up the given structure only using its self weight without any need for vibration and compaction during pouring process. On the other hand, the structural lightweight concrete (LWC) has emerged due to its lightness and all the advantages related to lower thermal insulating characteristics. The two materials open way to the lightweight self compacting concrete (LWSCC) in order to combine the favorable properties of LWC with those of SCC.However, the difference in density between the lightweight aggregate and cement paste complicate the mix design and production of LWSCC. Furthermore, existing mix design methods which are mostly borrowed from SCC design methods are empirical. Therefore, this thesis aims to develop a rational mix design method for suitable lightweight self-compacting concrete. This approach is built around a set of coherent data whose compaction index of granular skeleton and on the experimental data such as water absorption in the cement paste and segregation. From this method, different ranges of LWSCC are proposed to meet the requirements of the specification in terms of dry density and compressive strength. Its implementation was used to simulate and formulate LWSCC of workability classes from SF1 to SF3, density class from D1.8 to D2.0 and resistance class from LC35/38 to LC50/55. The mix design method also explored the total lightweight self compacting concrete (TLWSCC) that may constitute an innovative solution for the concrete industry in the context of the new thermal regulations for buildings
52

Etude d'un modèle de champ moyen en électrodynamique quantique / Study of a mean-field model in quantum electrodynamics

Sok, Jérémy 08 July 2014 (has links)
Les modèles de champ moyen en QED apparaissent naturellement dans la modélisation du nuage électronique des atomes lourds. Cette modélisation joue un rôle croissant en physique et chimie quantique, les effets relativistes ne pouvant pas être négligés pour ces atomes. En physique quantique relativiste, le vide est un milieu polarisable, susceptible de réagir à la présence de champ électromagnétique.On se place dans le cadre du modèle variationnel de Bogoliubov-Dirac-Fock (BDF) qui est une approximation de champ moyen de la QED sans photon (en particulier, les interactions considérées sont purement électrostatiques).Il est à noter que pour donner un sens au modèle BDF, il est nécessaire d'introduire une régularisation ultra-violette. Il se produit un phénomène de renormalisation de charge due à la polarisation du vide : la charge de l'électron observée dépend de la charge « nue » de l'électron et du paramètre de régularisation. On étudie rigoureusement ce phénomène ainsi que le problème de la renormalisation de la masse. Cette dernière est en lien avec l'existence d'un état fondamental pour le système d'un électron dans le vide, en l'absence de tout champ extérieur. En revanche, on montre l'absence de minimiseurs dans le cas de deux électrons.Enfin, on exhibe des points critiques de l'énergie BDF, interprétés comme des états excités du vide. On met en évidence le positronium, système métastable d'un électron et de son antiparticule le positron, ainsi que le dipositronium, molécule métastable constituée de deux électrons et de deux positrons.Les méthodes utilisées sont variationnelles (concentration-compacité, lemme de Borwein et Preiss). / In QED, mean-field models appear in the modelling of the electron clouds of heavy atoms. This modelling plays a increasing role in physics and in quantum chemistry: relativistic effects cannot be neglected in these atoms. In relativistic quantum physics the vacuum is a polarizable medium that can react to the presence of an electromagnetic field.We consider the so-called Bogoliubov-Dirac-Fock (BDF) model, a variational model which is a mean-field approximation of no-photon QED (in particular the interactions are purely electrostatic).We point out that an ultraviolet regularisation is necessary to properly define the BDF model. The vacuum polarisation leads to a \emph{renormalisation} phenomenon, the "observed" charge of the electron depends on its "bare" charge and the regularisation parameter. We rigorously study both the problem of charge renormalisation and mass renormalisation. This last one is linked to the existence of ground state in the case of an electron in the vacuum, without any external field. In contrast, we show there is no ground state in the case of two electrons.Finally we exhibit some critical points of the BDF energy which are interpreted as vacuum excited states. In particular, there are the positronium (a metastable system constituted by an electron and its antiparticle called the positron) and the dipositronium (a metastable molecule constituted by two electrons and two positrons).The methods that we use are variational (concentration-compactness, Borwein and Preiss's Lemma).
53

Analýza atraktorů zobecněných Newtonovských tekutin v 3d oblastech / Analýza atraktorů zobecněných Newtonovských tekutin v 3d oblastech

Žabenský, Josef January 2011 (has links)
We investigate a system of nonlinear partial differential equations, specifically the so-called Ladyzhenskaya model, in three spatial dimensions. It will be shown that after inclusion of a perturbation of a higher order, the model exhibits a considerably better behavior, in particular it will become quite straightforward to prove differentiability of solutions with respect to the initial condition. Due to this fact we may consequently employ the method of Lyapunov exponents to estimate the fractal dimension of the exponential attractor. First, however, it will be necessary to show existence and uniqueness of solutions, improved regularity and existence of a compact invariant set for the entire system.
54

Hyperbolic problems in fluids and relativity

Schrecker, Matthew January 2018 (has links)
In this thesis, we present a collection of newly obtained results concerning the existence of vanishing viscosity solutions to the one-dimensional compressible Euler equations of gas dynamics, with and without geometric structure. We demonstrate the existence of such vanishing viscosity solutions, which we show to be entropy solutions, to the transonic nozzle problem and spherically symmetric Euler equations in Chapter 4, in both cases under the simple and natural assumption of relative finite-energy. In Chapter 5, we show that the viscous solutions of the one-dimensional compressible Navier-Stokes equations converge, as the viscosity tends to zero, to an entropy solution of the Euler equations, again under the assumption of relative finite-energy. In so doing, we develop a compactness framework for the solutions and approximate solutions to the Euler equations under the assumption of a physical pressure law. Finally, in Chapter 6, we consider the Euler equations in special relativity, and show the existence of bounded entropy solutions to these equations. In the process, we also construct fundamental solutions to the entropy equations and develop a compactness framework for the solutions and approximate solutions to the relativistic Euler equations.
55

Oscillatory Solutions to Hyperbolic Conservation Laws and Active Scalar Equations / Oszillierende Lösungen von hyperbolischen Erhaltungsgleichungen und aktiven skalaren Gleichungen

Knott, Gereon 12 September 2013 (has links) (PDF)
In dieser Arbeit werden zwei Klassen von Evolutionsgleichungen in einem Matrixraum-Setting studiert: Hyperbolische Erhaltungsgleichungen und aktive skalare Gleichungen. Für erstere wird untersucht, wann man Oszillationen mit Hilfe polykonvexen Maßen ausschließen kann; für Zweitere wird mit Hilfe von Oszillationen gezeigt, dass es unendlich viele periodische schwache Lösungen gibt.
56

Urban Compactness: A Study Of Ankara Urban Form

Caliskan, Olgu 01 September 2004 (has links) (PDF)
Sustainable urban development is mentioned together with the concept of urban form in contemporary planning literature. The main reason behind this is a need for determining an ideal physical development scheme and its main principles of urban future in a broad term. Besides, the operational side of urban planning requires a concrete set of design codes in order to transform urban space in both macro and mezzo scale. At this point, the concept of urban compactness and the idea of Compact City have come into the agenda of planning. In the last decade, the model of compact city has become a prototype of sustainable urban form in developed countries. It is also argued whether compact urbanity is a nostalgic metaphor or an engineering solution. It has emerged as a reaction to the negative consequences of urban sprawl and suburbanization as the anti-urbanist urban phenomena in Western geographies. Hence, the relevance of urban compactness should be examined for developing and underdeveloped countries and their settlement structures. The basic motivation of the thesis is to examine the relevance and validity of urban compactness in the case of Turkey as a developing Eurasian country. For this end, the evolution of urban compactness as a fact and an idea in the historical context of developed countries and it&rsquo / s meaning for the developing world / Ankara is examined as a case study by re-reading its planning history and the transformation of its urban form from the point of view of compactness.
57

Analysis of several non-linear PDEs in fluid mechanics and differential geometry

Li, Siran January 2017 (has links)
In the thesis we investigate two problems on Partial Differential Equations (PDEs) in differential geometry and fluid mechanics. First, we prove the weak L<sup> p</sup> continuity of the Gauss-Codazzi-Ricci (GCR) equations, which serve as a compatibility condition for the isometric immersions of Riemannian and semi-Riemannian manifolds. Our arguments, based on the generalised compensated compactness theorems established via functional and micro-local analytic methods, are intrinsic and global. Second, we prove the vanishing viscosity limit of an incompressible fluid in three-dimensional smooth, curved domains, with the kinematic and Navier boundary conditions. It is shown that the strong solution of the Navier-Stokes equation in H<sup> r+1</sup> (r &GT; 5/2) converges to the strong solution of the Euler equation with the kinematic boundary condition in H<sup> r</sup>, as the viscosity tends to zero. For the proof, we derive energy estimates using the special geometric structure of the Navier boundary conditions; in particular, the second fundamental form of the fluid boundary and the vorticity thereon play a crucial role. In these projects we emphasise the linkages between the techniques in differential geometry and mathematical hydrodynamics.
58

MAPEAMENTO E PROPOSTA DE CONEXÃO DE FRAGMENTOS FLORESTAIS EM SANTA MARIA (RS) / MAPPING AND CONNECTION PROPOSAL OF FOREST FRAGMENTS IN SANTA MARIA (RS), BRAZIL

Silva, Natália Huber da 15 June 2015 (has links)
Recent studies which feature the urban area land use mapping Santa Maria do not have tree-canopy cover differentiation, as Deciduous Atlantic Forest and exotic tree plantations - mostly of Pinus sp. and Eucalyptus sp.. Thus, the study main objective is to carry out a forest fragments analysis of the Santa Maria‟s District Headquarters, seeking a connection proposal to maintain the faunistic genetic flux in a city neighborhood. In order to choose the neighborhood were identified and classified forest fragments in exotic and native, through the manual vectorization a scale of approximately 1: .2000, through Google Earth Pro₢ software with image of Digital Globe₢ satellite, from April 2014. This vectorization was applied to the map of the Headquarters District land use, getting big differences compared to the automatic classification of Maxver₢ in Landsat 8₢, from November, 2014. Through population data provided by the City Hall it was possible calculate a Tree-canopy Cover Index (of Deciduous Forest) per capita. Also, metric parameters as area, circularity and the distance between the fragments were regarded as priorities, respectively, and each one with eliminating character. After tabulating of fragments metrics, through the import of vectorized files for ArcGIS 10.0₢, was established the neighborhood in which the connection proposition was made, and this was carried out another map of use of neighborhood land with Digital Globe₢ image. For connecting proposal of forest fragments were used structural interventions in roads and reforestation areas with native or not invasive exotic species as mitigation measures to fragmentation. These structures are already in use at international, national and state level and most are easy to install or adapt to use of faunal biodiversity. As a result it was found that the city has a tree-canopy cover index per capita reasonably high, with an average of 47.6 m² / inhab. But, dividing the city in Administrative Regions, there are greater differences into this index, that declines to 0.01 m² / inhab. in western region of the city. Based on data like these, it was found that the agricultural practice deforests more than civil constructions in the city, in moving forward about Permanent Preservation Areas. As well, it was observed within the study area that the more distant the remaining fragments of Atlantic Forest are located of its area source, scarcer and smaller they are. Furthermore, it was statistically demonstrated that in urban areas, larger fragments tend to have a lower circularity. The neighborhood that was chosen by the metric mentioned was the Km 3, which houses a large remaining fragment of the Plateau Escarpment. This presented about half of its area covered by fragments of native species and, by having a low population index of 2,700 inhabitants to more than two million square meters of rainforest, has about 660 square meters of tree-canopy native cover per inhabitant, a very high rate for an embedded area in the urban perimeter. / Estudos recentes que apresentam mapeamento de uso do solo do perímetro urbano de Santa Maria, não apresentam diferenciação de cobertura arbórea entre Floresta Estacional Decidual e plantações arbóreas exóticas - em sua maior parte de Pinus sp. e Eucalyptus sp. Assim, tem-se como objetivo principal deste estudo a análise dos fragmentos florestais do Distrito Sede de Santa Maria, visando uma proposta de conexão para a manutenção do fluxo gênico faunístico em um bairro da cidade. Para a escolha do bairro, foram identificados e classificados fragmentos florestais em exóticos e nativos, através da vetorização manual a uma escala de aproximadamente 1: 2.000, pelo software Google Earth Pro₢ com imagem do satélite Digital Globe₢ de abril de 2014. Esta vetorização foi aplicada ao mapa de uso do solo do Distrito Sede, obtendo grandes diferenças em comparação à classificação automática do Maxver na imagem Landsat 8₢, de novembro de 2014. Através de dados populacionais disponibilizados pela Prefeitura pôde-se calcular um Índice de Cobertura Arbórea (Floresta Estacional Decidual) por habitante. Ainda, características métricas de área, circularidade e a distância entre os fragmentos foram consideradas como prioridades, respectivamente, sendo cada parâmetro de caráter eliminatório. Depois de realizado o tabelamento da métrica dos fragmentos, através de importação dos arquivos vetorizados para o ArcGis 10.0₢, estabeleceu-se o bairro em que foi realizada a proposta de conexão e, deste, foi elaborado outro mapa de uso do solo com imagem Digital Globe₢. Para a proposta de conexão dos fragmentos florestais foram utilizadas intervenções estruturais em rodovias e áreas de reflorestamento com espécies nativas ou exóticas não invasoras como alternativas mitigadoras à fragmentação. Estas intervenções rodoviárias são utilizadas a nível internacional, nacional e estadual, sendo a maioria de fácil instalação ou adaptação para utilização da biodiversidade faunística. Como resultados verificou-se que a cidade possui um índice de cobertura arbórea por habitante razoavelmente alto, tendo média de 47,6 m²/hab. Porém se dividirmos a cidade em Regiões Administrativas, há diferenças discrepantes em que esse índice decai para 0,01 m²/hab., como na zona Oeste da cidade. Através de dados como estes, concluiu-se que a prática agrícola desmata mais que as instalações de construção civil na cidade, avançando mais sobre Áreas de Preservação Permanente. Também observou-se dentro da área deste estudo que, quanto mais distantes os fragmentos remanescentes de Mata Atlântica situam-se de sua área-fonte, mais escassos e menores eles são. Além disso, foi comprovado estatisticamente que em áreas urbanas, maiores fragmentos tendem a ter menor circularidade. O bairro que foi escolhido através da métrica citada foi o Km 3, que abriga um grande fragmento remanescente do Rebordo do Planalto. Este apresentou cerca de metade de sua área coberta por fragmentos de espécies nativas e, por contar com um baixo índice populacional de 2.700 habitantes para mais de dois milhões de m² de mata atlântica, dispõe cerca de 660 m² de cobertura arbórea por habitante, índice altíssimo para uma área inserida do perímetro urbano.
59

Compactação do solo e sua influência nas propriedades físicas do solo e crescimento e rendimento de culturas / Soil compaction influence on soil physical properties and on crop growth and yield

Suzuki, Luis Eduardo Akiyoshi Sanches 28 February 2005 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Sol compaction effects on soil and plants has been subject of several studies. However, several parameters are used to evaluate soil compaction like bulk density and soil penetration resistance, but these parameters are dependent of soil type and moisture, therefore, the study of a parameter that could compare the different soils would facilitate the soil compaction studies. This work was divided in four chapters. In the first chapter the objective was to evaluate some physical-mechanical parameters of Alfisols and Oxisols submitted to different tillages. Six soils from Rio Grande do Sul state, Brazil, were collected, with clay content varying from 100 to 650 g kg-1. The core samples were collected from 0.08-0.13 m layer, equilibrated to the tension of 33 kPa and submitted to uniaxial compression test with application of successive and static loads. Based on the vertical displacement measured in the consolidometer after application of each load, were evaluated initial (Dsi) and final (Dsf) bulk density, deformation (Def), initial saturation degree (Gsi), initial volumetric moisture (qvi), pre compression stress (sp) and compression index (Cc) by Casagrande s method. Results indicated that managements with larger compaction presented smaller deformation and susceptibility to compaction; managements with recent revolviment of soil presented larger displacement from their compression curves, showing larger susceptibility to compaction; the Oxisol with larger clay content, due ability to retain more water in determined tension and due larger susceptibility to compaction, need to be more careful with traffic of machines than sandy soils. The second chapter aimed to study some physical properties of Alfisols and Oxisols from Rio Grande do Sul state, Brazil, submitted to different tillages and its influence on root growth and soybean yield. R esults showed larger densities in the approximate depth of 0.10 m and the penetration resistance do not appear in layers with uniform resistance, are spaces with larger and smaller resistance; the root evaluation, even visually, it is a good indicative of the soil physical condition and the bulk density and penetration resistance, if appraised with moisture near field capacity, are good indicators of the soil for plant development; crop yield was associated to soil physical conditions. The third chapter had as objective evaluate the effect of the particles size and tillage in the degree of compactness and to verify the best pressure to obtain the reference bulk density. Six soils of Rio Grande do Sul state, Brazil, submitted to different tillages were collected, with clay content varying from 100 to 650 g kg-1. For determination of the bulk density core samples were collected from layers of 0-0.05, 0.05-0.10, 0.10-0.15, 0.15-0.20, 0.20-0.25 and 0.25-0.30 m and for evaluation of the reference bulk density core samples were collected in the layer of 0.08-0.13 m. For determination of the reference bulk density samples were equilibrated to the tension of 33 kPa and submitted to the uniaxial compression test, with application in each soil sample only one load of 200, 400, 800, 1600 kPa and 3200 kPa. It was also obtained the soil compression curve with application of successive loads in each soil sample to compare the results obtained with the samples that was applied only one load. They were evaluated also the macroporosity and soil penetration resistance, yield and root development of soybean. In agreement with the obtained results, the load of 1600 kPa was the best pressure to obtain the reference bulk density in the uniaxial compression test using core samples, independent if applying just the load of 1600 kPa or from the load of 1600 kPa of the soil compression curve; the largest soybean yield was obtained with degree of compactness of 82% for Alfisols and 85% for Oxisols and the degree of compactness was a good indicator of the physical conditions of the soil, presenting good relationship with soil penetration resistance, macroporosity, root growth and soybean yield; the degree of compactness looks like independent from particle size, based especially in the results of crop yield and macroporosity in function of degree of compactness. The fourth chapter aimed to study the effect of different compaction states on the soil physical properties and growth and yield of soybean, corn and wheat. An experiment was set in the Cooperativa Regional Tritícola Serrana Ltda (COTRIJUÍ) , Ijuí city, Rio Grande do Sul state, Brazil, in an Oxisol. The completely randomized experimental design was used, in a bifactorial with split plots, with three repetitions. The main plots had three compaction states (PDC no tillage during six years + four passes of a machine with mass of 10 Mg in the agricultural year 2003/2004; PD no tillage during six years; Escarif no tillage during six years + chisel and harrowing in the agricultural year 2003/2004) and the split plots had soybean and corn. The soil physical properties (macroporosity, microporosity, total porosity, bulk density and soil penetration resistance) and development and yield of soybean, corn and wheat were measured. The results showed that the additional compaction presented increment of the soil resistance to penetration until the depth of 0.12 m; soil compaction influenced negatively soil physical properties; soybean and wheat were sensitive to compaction, soybean and corn had reduced heights and the wheat and soybean had their root system reduced length, for the additional compaction; soil compaction affected crop yield of corn, soybean and wheat, been the larger yields verified in no tillage and the smaller in treatments with additional compaction; the larger wheat yield was observed in the succession with soybean / A compactação do solo é tema de vários estudos que visam avaliar seus efeitos no solo e na planta. Vários parâmetros são utilizados para avaliar a compactação do solo, como densidade do solo e resistência à penetração, mas esses parâmetros são dependentes do tipo e da umidade do solo; portanto, o estudo de parâmetros que comparam diferentes solos facilita o estudo sobre compactação do solo. Este trabalho foi dividido em quatro capítulos. No primeiro capítulo o objetivo foi avaliar alguns parâmetros físico-mecânicos de Argissolos e Latossolos submetidos a diferentes sistemas de manejo. Foram coletados seis solos do Rio Grande do Sul, com granulometria variando, aproximadamente, entre 100 a 650 g kg-1 de argila. As amostras com estrutura preservada foram coletadas na profundidade de 0,08-0,13 m e equilibradas à tensão de 33 kPa, e submetidas ao teste de compressão uniaxial com aplicação de cargas sucessivas e estáticas. Baseado no deslocamento vertical medido no consolidômetro após a aplicação de cada carga foram avaliados a densidade do solo inicial (Dsi) e final (Dsf), deformação (Def), grau de saturação inicial (Gsi), umidade volumétrica inicial (qvi), e pressão de pré-consolidação (sp) e índice de compressão (Cc) determinados pelo método de Casagrande. Os resultados indicaram que manejos com maior estado de compactação inicial apresentaram menor deformação e menor suscetibilidade do solo à compactação; sistemas de manejo com revolvimento do solo recente apresentaram maior deslocamento de suas curvas de compressão, mostrando maior suscetibilidade à compactação; o Latossolo Vermelho distroférrico típico, pela capacidade de reter mais água a uma determinada tensão e pela maior suscetibilidade à compactação, necessita de maior cuidado com o tráfego de máquinas do que solos arenosos. O segundo capítulo objetivou estudar algumas propriedades físicas de Argissolos e Latossolos do Rio Grande do Sul submetidos a diferentes sistemas de manejo do solo e suas influências no crescimento radicular e rendimento da cultura da soja. Os resultados mostraram que independente do solo e manejo, de modo geral as maiores densidades foram encontradas na profundidade aproximada de 0,10 m; os níveis de resistência do solo à penetração não se apresentam em camadas uniformes, ocorrem espaços de maior e menor resistência; a densidade do solo e a resistência à penetração se avaliada com umidade próxima à capacidade de campo, mostraram-se bons indicadores do solo para desenvolvimento da planta e a avaliação do sistema radicular, mesmo que apenas visual, é um bom indicativo da condição física do solo; o rendimento esteve associado às condições físicas dos solos. O terceiro capítulo teve como objetivo avaliar o efeito da textura e do manejo do solo no grau de compactação e verificar a melhor pressão para se obter a densidade referência. Foram coletados seis solos do Rio Grande do Sul submetidos à condições de manejo distintas, com granulometria, aproximadamente, entre 100 e 650 g kg-1 de argila. Para a determinação da densidade do solo foram coletadas amostras com estrutura preservada nas camadas de 0-0,05; 0,05-0,10; 0,10-0,15; 0,15-0,20; 0,20-0,25 e 0,25-0,30 m e para avaliação da densidade referência foram coletadas amostras com estrutura preservada na camada de 0,08-0,13 m. Para a determinação da densidade referência, as amostras foram equilibradas à tensão de 33 kPa e submetidas ao teste de compressão uniaxial, com aplicação em cada amostra de solo carga única de 200, 400, 800, 1600 kPa e 3200 kPa. Também foi obtida a curva de compressão do solo com aplicação de cargas sucessivas em cada amostra de solo para poder comparar os resultados obtidos com as amostras em que foi aplicada carga única. Foram avaliados também a macroporosidade e a resistência do solo à penetração, e o crescimento radicular e o rendimento da cultura da soja. Os resultados obtidos mostraram que a carga de 1600 kPa foi a melhor pressão para se obter a densidade referência no teste de compressão uniaxial utilizando amostras de solo com estrutura preservada, independente de ser obtida de aplicação de carga única ou da curva de compressão do solo; o maior rendimento da soja é obtido com grau de compactação, em média de 82% para os Argissolos e 85% para os Latossolos; o grau de compactação mostrou-se um bom indicador das condições físicas do solo, apresentando boa relação com rendimento da cultura da soja, resistência à penetração, macroporosidade e desenvolvimento radicular; o grau de compactação parece ser independente da ranulometria do solo, baseado principalmente nos resultados de rendimento e macroporosidade em função do grau de compactação. O quarto capítulo objetivou estudar o efeito de diferentes condições de compactação sobre as propriedades físicas do solo e crescimento e rendimento das culturas soja, milho e trigo. Para isso, foi conduzido um experimento no campo tecnológico da Cooperativa Regional Tritícola Serrana Ltda (COTRIJUÍ), município de Ijuí (RS), em um Latossolo Vermelho distroférrico típico. Foi utilizado o delineamento experimental inteiramente casualizado, em um bifatorial com parcelas subdivididas, com três repetições, tendo nas parcelas principais três estados de compactação (PDC - Plantio direto há seis anos que recebeu compactação adicional por quatro passadas de máquina com massa de 10 Mg no ano agrícola 2003/2004; PD - Plantio direto há seis anos; Escarif - Plantio direto há seis anos, sendo escarificado e gradeado no ano agrícola 2003/2004) e nas subparcelas as culturas de verão soja e milho e trigo no inverno. Foram avaliadas as propriedades físicas do solo macroporosidade, microporosidade, porosidade total, densidade do solo e resistência do solo à penetração e o crescimento e rendimento das culturas soja, milho e trigo. Os resultados mostraram que a compactação adicional apresentou incremento da resistência do solo à penetração até a profundidade de 0,12 m e afetou negativamente as propriedades físicas do solo; as culturas milho, soja e trigo foram sensíveis à compactação, tendo a altura das culturas soja e milho e comprimento radicular das culturas soja e trigo, reduzidos pela compactação adicional; a compactação do solo influenciou o rendimento das culturas soja, milho e trigo, sendo os maiores rendimentos verificados no plantio direto e os menores no tratamento com compactação adicional, e o maior rendimento do trigo foi observado na sucessão com soja
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Concentration-compactness principle and applications to nonlocal elliptic problems

Souza, Diego Ferraz de 13 December 2016 (has links)
Submitted by ANA KARLA PEREIRA RODRIGUES (anakarla_@hotmail.com) on 2017-08-23T16:14:54Z No. of bitstreams: 1 arquivototal.pdf: 1030469 bytes, checksum: fd75dc32951ccd2147ed562db94af22a (MD5) / Made available in DSpace on 2017-08-23T16:14:54Z (GMT). No. of bitstreams: 1 arquivototal.pdf: 1030469 bytes, checksum: fd75dc32951ccd2147ed562db94af22a (MD5) Previous issue date: 2016-12-13 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES / The main goal of this work is to analyze concentration-compactness principles for fractional Sobolev spaces based on the concentration compactness principle of P.-L. Lions and in the pro le decomposition for weak convergence in Hilbert spaces due to K. Tintarev and K.-H Fieseler. As application, we address questions on compactness of the associated energy functional to the following nonlocal elliptic problems, $' ''''''&' ''''''% p qsu fpx; uq in RN; p qsu 􀀀 apxqu fpx; uq in RN; $&% p qsu 􀀀 V pxqu 􀀀 Kpxq u fpx; uq 􀀀 gpx; uq in R3; p q Kpxqu2 in R3; where 0   s   1; 0     1; 2 􀀀 4s ¥ 3; ¡ 0 and Kpxq ¥ 0 belongs to a suitable Lebesgue space. We obtain existence results for a wide class of possible singular potentials apxq; not necessarily bounded away from zero and for oscillatory nonlinearities in both subcritical and critical growth range that may not satisfy the Ambrosetti-Rabinowitz condition. / O objetivo principal deste trabalho é analisar princípios de concentração de compacidade para espaços de Sobolev fracionários baseados na concentração de compacidade de P.-L. Lions e no per l de decomposição para convergência fraca em espaços de Hilbert devido a K. Tintarev e K.-H Fieseler. Como aplicação, abordamos questões sobre a compacidade do funcional energia associado aos seguintes problems elípticos não locais, $' ''''''&' ''''''% p qsu fpx; uq em RN; p qsu 􀀀 apxqu fpx; uq em RN; $&% p qsu 􀀀 V pxqu 􀀀 Kpxq u fpx; uq 􀀀 gpx; uq em R3; p q Kpxqu2 em R3; onde 0   s   1; 0     1; 2 􀀀 4s ¥ 3; ¡ 0 e Kpxq ¥ 0 pertence a um espaço de Lebesgue adequado. Obtemos resultados de existência para uma vasta classe de potenciais apxq possivelmente singulares, não necessariamente limitados por baixo por uma constante positiva e para não linearidades oscilatórias em ambos os crescimentos subcríticos e críticos que podem não satisfazer a condição de Ambrosetti-Rabinowitz.

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