Dissertations / Theses: 'Cam Clay'

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Tam, Heng-Kong. "Some applications of Cam-clay in numerical analysis." Thesis, City University London, 1992. http://openaccess.city.ac.uk/7885/.

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The research described in this thesis investigated some applications of Cam-clay in numerical analyses. Single element analysis using the program CASIS was conducted to model undrained and drained triaxial compression tests to investigate the relative importance of the critical state soil parameters and streis history on the calculated soil behaviour. The values of these parameters covered the range of most commonly occurring natural soils. The investigation was extended to finite element modelling of plate loading tests using the computer program CRISP to examine the relative importance of the critical state soil parameters and stress history on the calculated undrained plate-soil behaviour. The capability of finite element coupled consolidation analysis of boundary value problems was demonstrated by the simulation of laboratory hydraulic fracturing experiments. The effects of rate of cavity water pressure increase, bore size, confining pressure and overconsolidation ratio on fracturing pressures were examined. The results of the parametric study of triaxial compression tests and plate loading tests were quantified in terms of stiffness (or tangent modulus), strength (or bearing pressure) and strain (or settlement) at the initial, yield, peak and ultimate states in the stress-strain (or pressure-settlement) response and allowed the comparison of these quantities for changing values of the soil model parameters. The studies revealed that the parameter x/A was the most influential because the initial states of soil were dependent on the values of ic and A and this dependence affected the subsequent stress-strain behaviour. In the prediction of movements of soil structures, the parameters x, A and a' are the most influential and their values should be critically evaluated for input in numerical analyses. In prediction of stability, the values of x, A and M are the most important ones. The work showed that the hydraulic fracturing phenomenon can be modelled by finite element coupled consolidation analysis. The computer program CRISP was validated against closed-form solutions and was found to predict the hydraulic fracturing phenomenon with a reasonable. degree of accuracy when the results were compared with the experimental data obtained by Mhach (1991). It was found that the rate of cavity water pressure increase had a significant influence in the prediction of fracturing pressure. The confining pressure was an important factor whereas the effects of bore size and overconsolidation ratio had some effects but were not as significant as the first two.

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Lodi, Paulo César. "Aplicação do modelo cam-clay modificado a um solo arenoso." Universidade de São Paulo, 1998. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-23032007-151306/.

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O modelo cam-clay modificado foi aplicado aos resultados experimentais obtidos para um solo arenoso típico da cidade de São Carlos. Os ensaios de compressão triaxial foram conduzidos em equipamento moderno, com instrumentação interna, segundo distintas trajetórias de carregamento. Verificou-se que os resultados obtidos em termos de modelagem foram satisfatórios, principalmente quando a tensão octaédrica (p\') foi diminuida durante os carregamentos. Nesse caso, tanto em termos de modelagem como de resultados experimentais, houve expansão de volume do solo. Com o aumento da tensão octaédrica, verificou-se a ocorrência de compressão volumétrica do solo. Observou-se que o modelo apresenta uma previsão de deformações axiais maiores do que as observadas experimentalmente nas trajetórias de -30, -50, 30, 40, 50, 60, 120 graus e no ensaio triaxial convencional com \'sigma\' 3 = 100 kPa. Além disso, determinou-se a superfície inicial de plastificação do solo utilizando-se dois critérios que tenderam a fornecer valores de tensão de cedência aproximadamente iguais, notando-se que a condição de fluxo associado não é obedecida.
The modified cam-clay model was used to model experimental results of a sandy soil from São Carlos - SP. Triaxial compression tests were performed using Bishop - Wesley cell with internal transducers to measure axial and radial strains. It was observed that the model fairly fitted experimental results, specially when medium effective stress (p\') is reduced during loading. In this case, both the model and the experimental results, showed volume increase. When (p\') increases the model and the tests showed a tendency to give volumetric compression, although the values were differents. The model yielded strains larger than that measured in the tests when the stress-paths were of -30, -50, 30, 40, 50, 60, 120 degrees and in axial compression test with 100 kPa of confining pressure. Besides that, initial yield surface of soil was calculated from test results using two different criteria which gave about the same yield stress and it is show that normality rule was not satisfied in this soil.

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Nader, José Jorge. "Modelos elasto-plásticos para solos: o Cam-Clay e sua aplicação a diferentes trajetórias de tensão." Universidade de São Paulo, 1993. http://www.teses.usp.br/teses/disponiveis/3/3145/tde-03042018-072402/.

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A deformação dos solos é, atualmente, objeto de intensas pesquisas em todo o mundo movidas pelas necessidades da engenharia geotécnica. Este trabalho, que aborda o tema nos aspectos teórico e experimental, inicia-se revendo as relações constitutivas elasto-plásticas e o modelo Cam-Clay, cuja formulação matemática é apresentada de um modo diferente do usual. O modelo é construído de forma sistêmica a partir das equações elasto-plásticas gerais. Na parte experimental investiga-se o comportamento de um solo siltoso remoldado, quando submetido a ensaios triaxiais com diferentes trajetórias de tensão após adensamento isotrópico. Por fim comparam-se resultados experimentais e teóricos. Conclui-se que o modelo comporta-se melhor nas trajetórias de tensão em que não há diminuição da tensão octaédrica, embora preveja deformações volumétricas exageradas. Por sua vez, nas trajetórias em que há diminuição da tensão octaédrica, a diferença entre o comportamento previsto e o observado é grande, revelando que o modelo não deve ser aplicado nesses casos.
Soil deformation is today a subject of intense research all over the world motivated by the necessities of the geotechnical engineering. This work, which approaches the theme in both theoretical and experimental aspects, reviews the elastoplastic constitutive relations and the Cam-Clay model, and examines the behavior of a remoulded silty soil when subjected to different stress paths. Following a brief exposition of some basic Continuum Mechanics concepts, the elastic and elastoplastic constitutive equations are presented in a general form, which serve as a basis for several soil models. After a discussion about soil behavior and its representation by models, the Cam-Clay mathematical formulation is presented in an unusual form: it begins with the general elastoplastic constitutive equations, the elastic stress-strain relation, the yield function and the hardening law being given. The plastic stress-strain relation in deduced. In the experimental part the behavior of a remoulded silty soil from the Escola Politécnica Foundation Experimental Field is investigated. Oedometric, isotropic and triaxial compression tests (that were performed as part of the research) are described and analysed. Among them the triaxial tests with different stress paths after isotropic consolidation constitute the principal subject of analysis. Finally the Cam-Clay equations are integrated along the tests stress paths and the experimental e theoretical results are confronted. The conclusions is that the model behaves better in stress paths where there is no octabedral stress reduction, although even then it predicts exaggerated volumetric strains. In its turn, in stress paths where there is an octahedral stress reduction the difference between predicted and observed behavior is large, revealing that the model should not be applied in such cases.

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Brulin, Jérôme. "Modélisation thermomécanique d'un creuset de haut fourneau." Thesis, Orléans, 2010. http://www.theses.fr/2010ORLE2047/document.

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Le creuset est une structure majoritairement composée de matériaux réfractaires destinés à supporter de fortes sollicitations thermomécaniques, dues au contact direct de ses parois internes avec la fonte à 1500°C. L’objectif de cette thèse est de développer un modèle thermomécanique de creuset capable de localiser les zones sensibles de la structure et d’estimer les contraintes. Des blocs de carbone, des structures maçonnées (briques avec mortier) et un pisé carboné sont les principaux constituants du creuset. Afin d’identifier leur comportement, des essais de caractérisation ont été développés pour des températures atteignant les 1500°C. Un modèle de type Cam-Clay modifié est proposé pour modéliser le comportement compactant du pisé. L’influence de la température et des fortes pressions est prise en compte. Une bonne corrélation est obtenue entre les résultats expérimentaux et numériques. Les structures maçonnées, en contact direct avec la fonte, sont fortement sollicitées, ce qui peut conduire à l’ouverture des joints de mortier. La modélisation proposée pour ces structures est basée sur une approche micro-macro où les briques et le mortier sont remplacés par un matériau homogène équivalent, et ce pour différents états d’ouverture de joints. La non-linéarité du comportement est reproduite grâce à un critère d’ouverture en contrainte, qui permet le passage d’un état à un autre. Les propriétés homogénéisées sont obtenues par homogénéisation périodique en s’appuyant sur une approche énergétique. La modélisation d’un essai de la littérature permet la validation du modèle. La modélisation finale du creuset est confrontée aux résultats de l’instrumentation d’un creuset. Une bonne concordance entre ces résultats est obtenue
The blast furnace hearth is mainly composed of refractory materials to support strong thermo-mechanical loads. Indeed, there is a direct contact between its internal walls and the molten pig iron at 1500°C. The objective of this thesis is to develop a thermo-mechanical model able to locate the sensitive areas and to estimate the stress fields. Carbon blocks, masonries (bricks and mortars) and a carbon ramming mix are the main constituents of the hearth. In order to identify their behaviours, characterization tests have been developed for temperatures up to 1500°C. A modified Cam-Clay model is proposed in order to reproduce the hardening behaviour of the ramming mix. The influences of temperature and pressure are taken into account. Experimental and numerical results are in good agreement. Masonries, submitted to high temperature gradients are highly stressed, which can lead to the opening of the mortar joints. The proposed masonry modelling is based on a micro-macro approach where bricks and mortars are replaced by an equivalent homogenous material for different joint states. The non-linearity of the behaviour is reproduced thanks to a stress criterion, allowing the transition from one state to another. Homogenized properties are obtained by periodic homogenization with an energetic approach. The modeling of a shear test available in the literature allows the validation of this model. The final modelling of a hearth is compared with in-situ instrumentation results. A good agreement is reached between these results

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Arvelo, Jose. "ADAPTING THE MODIFIED CAM CLAY CONSTITUTIVE MODEL TO THE COMPUTATIONAL ANALYSIS OF DENSE GRANULAR SOILS." Master's thesis, University of Central Florida, 2005. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/2452.

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The computational constitutive Modified Cam Clay Model (MCCM) was developed at Cambridge to study the behavior of clays and has been proven to be effective. In this study, this model is extended to the case of dense sands to analyze the accuracy of the stress-strain behavior. This analysis is based on triaxial test data applied to remolded and compacted sand samples under drained conditions. The laboratory triaxial tests were performed by the Florida Department of Transportation to research the permeability effect in sandy soils compacted up to 95% of maximum unit weight at the optimum moisture content. Each soil sample was tested using different stress paths. In addition, these data were also used to obtain the soil parameters. These soil parameters are used as input data for the Modified Cam Clay Model. Moreover, a computer program in MATLAB was developed based on the MCCM constitutive theory and application in order to predict the stress-strain response for overconsolidated soils under drained condition. Based on observations of the qualitative behavior of these soils, a modification is proposed in this thesis to the original constitutive model to improve the predicted stress-strain behavior. The results of the computer program are typically presented in the deviatoric stress versus shear strain and the stress path plane (deviatoric stress versus mean effective stress). These are the principal plots used for the behavior prediction of soil specimens. Furthermore, the results of the computer program were compared to the laboratory triaxial test data. In general, it is may be concluded that, MCCM with some modification, is applicable to dense sands.
M.S.C.E.
Department of Civil and Environmental Engineering
Engineering and Computer Science
Civil Engineering

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Sánchez, Henríquez Felipe Ignacio. "Análisis numérico y experimental del método de consolidación por vacío para relaves integrales." Tesis, Universidad de Chile, 2016. http://repositorio.uchile.cl/handle/2250/142659.

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Ingeniero Civil
El presente trabajo de título analiza el método de consolidación por vacío y su aplicabilidad para el mejoramiento de un relave integral. El estudio se basa en la comparación de resultados obtenidos a partir de un modelo experimental, modelaciones numéricas de elementos finitos y soluciones analíticas recopiladas de la literatura técnica. El modelo experimental aplica succión generada por una bomba de vacío sobre una columna de relave integral saturado y monitorea la evolución temporal de la deformación vertical, simulando la aplicación de esta técnica en suelos depositados en la cubeta de un tranque de relaves. Además, se realizan simulaciones numéricas de elementos finitos con el software Abaqus para reproducir las condiciones del modelo experimental y poder capturar las mediciones de laboratorio. El comportamiento elasto-plástico del material se simula con el modelo constitutivo Cam-Clay Modificado (MCCM). La calibración de los parámetros de compresibilidad y de conductividad hidráulica del material se realiza con ensayos de laboratorio considerando dos estados de depositación y otros parámetros se adoptan de los trabajos de Cifuentes y Verdugo (2007) y Conejera (2016). La aplicación de -80 kPa de vacío induce deformaciones verticales en la columna de relave integral que son equivalentes a las inducidas por la aplicación de 3,5 - 4 metros de material de relleno. El fenómeno de consolidación de vacíos se puede simular numéricamente con un software de elementos finitos y el uso de un modelo constitutivo elasto-plástico, como Cam-Clay Modificado (MCCM). Los parámetros críticos para modelar apropiadamente el fenómeno son los parámetros de compresibilidad y la conductividad hidráulica del material. Si bien estos parámetros se pueden estimar con ensayos estándares de laboratorio, se requieren algunos ajustes para estimar el asentamiento máximo y el tiempo de consolidación.

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Ghahremannejad, Behrooz. "Thermo-Mechanical Behaviour of Two Reconstituted Clays." Thesis, The University of Sydney, 2003. http://hdl.handle.net/2123/492.

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The effect of temperature on soil behaviour has been the subject of many studies in recent years due to an increasing number of projects related to the application of high temperature to soil. One example is the construction of facilities for the disposal of hot high level nuclear waste canisters (150-200C) several hundred meters underground in the clay formations. Despite this, the effects and mechanism by which temperature affects the soil properties and behaviour are not fully known. A limited amount of reliable experimental data, technological difficulties and experimental methods employed by different researchers could have contributed to the uncertainties surrounding the soil behaviour at elevated temperature. Also several thermo-mechanical models have been developed for soil behaviour, but their validity needs to be examined by reliable experimental data. In this research, efforts have been made to improve the experimental techniques. Direct displacement measuring devices have been successfully used for the first time to measure axial and lateral displacements of clay samples during tests at various temperatures. The thermo mechanical behaviour of two reconstituted clays has been investigated by performing triaxial and permeability tests at elevated temperature. Undrained and drained triaxial tests were carried out on normally consolidated and over consolidated samples of M44 clay and Kaolin C1C under different effective stresses, and at temperatures between 22C and 100C. Permeability tests were carried out on samples of M44 clay at temperatures between 22C and 50C. The effects of temperature on permeability, volume change, pore pressure development, shear strength and stiffness, stress strain response and critical state parameters for different consolidation histories have been investigated by comparing the results at various temperatures. The results are also compared with the predictions of two models. It has been found that at elevated temperature the shear strength, friction angle and initial small strain stiffness reduce whereas permeability increases. The slope of the swelling line in the v-p� plane has been found to reduce with temperature. The slope of the isotropic normal consolidation line (INCL) and critical state line (CSL) in the v-p� plane have been observed to be independent of temperature, but both the INCL and the CSL shift downwards to lower locations as temperature increases. The deformations during drained cooling and re heating cycles have been found to be elastic and to simply reflect the expansivity of the soils solid particles. The thermal volume changes during undrained heating have been observed to be direct results of the thermal expansion of water and clay particles. The internal displacement measuring devices have been found to produce reliable data for the variation of strains at elevated temperature.

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Ghahremannejad, Behrooz. "Thermo-Mechanical Behaviour of Two Reconstituted Clays." University of Sydney. Civil Engineering, 2003. http://hdl.handle.net/2123/492.

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The effect of temperature on soil behaviour has been the subject of many studies in recent years due to an increasing number of projects related to the application of high temperature to soil. One example is the construction of facilities for the disposal of hot high level nuclear waste canisters (150-200C) several hundred meters underground in the clay formations. Despite this, the effects and mechanism by which temperature affects the soil properties and behaviour are not fully known. A limited amount of reliable experimental data, technological difficulties and experimental methods employed by different researchers could have contributed to the uncertainties surrounding the soil behaviour at elevated temperature. Also several thermo-mechanical models have been developed for soil behaviour, but their validity needs to be examined by reliable experimental data. In this research, efforts have been made to improve the experimental techniques. Direct displacement measuring devices have been successfully used for the first time to measure axial and lateral displacements of clay samples during tests at various temperatures. The thermo mechanical behaviour of two reconstituted clays has been investigated by performing triaxial and permeability tests at elevated temperature. Undrained and drained triaxial tests were carried out on normally consolidated and over consolidated samples of M44 clay and Kaolin C1C under different effective stresses, and at temperatures between 22C and 100C. Permeability tests were carried out on samples of M44 clay at temperatures between 22C and 50C. The effects of temperature on permeability, volume change, pore pressure development, shear strength and stiffness, stress strain response and critical state parameters for different consolidation histories have been investigated by comparing the results at various temperatures. The results are also compared with the predictions of two models. It has been found that at elevated temperature the shear strength, friction angle and initial small strain stiffness reduce whereas permeability increases. The slope of the swelling line in the v-p� plane has been found to reduce with temperature. The slope of the isotropic normal consolidation line (INCL) and critical state line (CSL) in the v-p� plane have been observed to be independent of temperature, but both the INCL and the CSL shift downwards to lower locations as temperature increases. The deformations during drained cooling and re heating cycles have been found to be elastic and to simply reflect the expansivity of the soils solid particles. The thermal volume changes during undrained heating have been observed to be direct results of the thermal expansion of water and clay particles. The internal displacement measuring devices have been found to produce reliable data for the variation of strains at elevated temperature.

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Agofack, Nicolaine. "Comportement des ciments pétroliers au jeune âge et intégrité des puits." Thesis, Paris Est, 2015. http://www.theses.fr/2015PEST1040.

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Lors du forage des puits d'hydrocarbure, une pâte de ciment est coulée dans l'espace annulaire entre le cuvelage en acier et les formations géologiques traversées. Pompée à l'état liquide, cette pâte de ciment fait sa prise le long du puits sous différentes conditions de température et de pression. La gaine de ciment ainsi mise en place a pour principales fonctions de promouvoir l'étanchéité pour protéger le casing contre la corrosion, de fournir le support mécanique pour assurer la stabilité du puits et d'isoler les différents fluides dans les couches traversées. Au cours de sa vie dans le puits, depuis le forage à la complétion et de la production à l'abandon, la gaine de ciment est soumise à différentes sollicitations mécaniques et thermiques qui peuvent l'endommager et altérer ses principales fonctions. La réponse de la pâte de ciment soumis à ces sollicitations dépend non seulement des conditions d'hydratation mais aussi de l'histoire des chargements précédemment appliqués. La prédiction du comportement de la gaine de ciment doit donc se faire à l'aide d'une modélisation numérique qui nécessite une loi de comportement pour la pâte de ciment. Le but de cette thèse est d'établir une loi de comportement de la pâte de ciment en cours d'hydratation pendant le jeune-âge (les 144 premières heures). Pour ce faire, des essais calorimétriques, de mesures de vitesse des ondes et des essais œdométriques ont été réalisés sur une pâte de ciment pétrolier classe G (w/c = 0,44) en cours de prise. Les conditions d'hydratation explorées vont de 7 à 30°C pour les températures et de 0,3 à 45MPa pour les pressions. Les résultats expérimentaux ont montré que les déformations volumiques de la pâte de ciment dues à son hydratation (retrait macroscopique) sont considérablement influencées par la contrainte sous laquelle la pâte de ciment s'hydrate. Plus la contrainte d'hydratation est élevée, plus élevé est le retrait macroscopique à 144 heures. Inversement, les déformations irréversibles dues à un cycle de chargement mécanique à cet âge sont moins importantes pour les contraintes plus élevées. Les résultats ont également montrés qu'au cours de la prise du ciment, il existe un temps critique à partir duquel l'application des cycles de chargement mécanique crée des déformations résiduelles dans la pâte de ciment. Ce temps critique arrive à un degré d'hydratation relativement constant, compris entre 0,18 et 0,20. Le modèle « Boundary Nucleation and Growth » a été utilisé pour étudier la dépendance de ce temps critique à la pression et à la température. Pour la modélisation du retrait macroscopique et de la réponse contrainte – déformation de la pâte de ciment, un modèle élasto-plastique chemo-poro-mécanique couplé, prenant en compte la désaturation du milieu, a été développé. Ce modèle utilise une surface de charge fermée de type Cam-Clay et une loi plastique associée. La loi d'écrouissage dépend des déformations volumiques plastiques et du degré d'hydratation. Les paramètres du modèle ont été évalués pour simuler le retrait macroscopique de la pâte de ciment hydratée sous différentes contraintes et températures. A un degré d'hydratation donnée, le modèle permet également de simuler la réponse contrainte-déformation due à un chargement mécanique
When drilling oil & gas well, cement slurry is pumped between the casing and the rock formation. This cement slurry sets at different conditions of temperature and pressure. The role of this cement sheath is to provide zonal isolation of different fluid along the well, to protect the casing against corrosion and to provide mechanical support. During the life of the well, from drilling to completion, production and P&A (plug and abandonment), the cement sheath is submitted to various mechanical and thermal loading that can potentially damage its properties and alter its performance. The behavior of cement paste submitted to theses solicitations depends both on the hydration condition and the loadings previously applied on the cement paste. The prediction of cement sheath behavior should be done by numerical modeling, which needs a constitutive law for cement paste. The purpose of the present work is to establish a constitutive law of cement paste during its hydration at early age (first 144 hours). The approach is based on combined calorimetric, wave velocities and oedometric tests on an oil-well class G cement paste with water-to-cement ratio equals 0.44. The hydration conditions explored are 7 to 30°C for temperature and 0.3 to 45MPa for pressure. The experimental results showed that the volumetric strain due to cement hydration (macroscopic shrinkage) depends considerably on the hydration pressure. At 144 hours of hydration, the macroscopic shrinkage increases with the hydration pressure increase. But, the residual strain due to application of mechanical cycle at this age is less for cement hydrated under higher pressure. The experimental results revealed that during the hydration there is a critical time after which, the application of mechanical loading can potentially induce residual strain in cement paste. This time is reached at constant hydration degree between 0.18 and 0.20. The Boundary Nucleation and Growth model was used to model the pressure and temperature dependence of this critical time. A coupled elasto-plastic chemo-poro-mechanical model is developed to simulate the macroscopic shrinkage of cement paste hydrated at different conditions of temperature and pressure. A modified Cam-Clay type yield surface with associate flow rule is used. The hardening law depends both on the degree of hydration and on the plastic volumetric strain. At constant degree of hydration, the developed model permits to simulate the stress – strain behavior of cement paste due to the mechanical loading

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NAKANO, MASAKI, AKIRA ASAOKA, and TOSHIHIRO NODA. "SOIL-WATER COUPLED FINITE DEFORMATION ANALYSIS BASED ON A RATE-TYPE EQUATION OF MOTION INCORPORATING THE SYS CAM-CLAY MODEL." 地盤工学会, 2008. http://hdl.handle.net/2237/20062.

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Turki, Kamel. "Approche des problèmes non réversibles des chaussées par le calcul avec éléments finis." Châtenay-Malabry, Ecole centrale de Paris, 1991. http://www.theses.fr/1991ECAP0179.

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Notre recherche a été conçue comme une étude de faisabilité pour l'aide à la conception et au diagnostic des chaussées par le calcul avec éléments finis. L'étude des chaussées se fait en général avec des méthodes semi-empiriques et des calculs en élasticité linéaire. Le but de cette recherche est d'essayer d'aborder par le calcul divers aspects non linéaires et non réversibles du comportement des chaussées depuis la construction jusqu'à la ruine. Dans la première partie le comportement de la roue est assimilé à celui du sol sous la fondation. L'originalité du travail vient en particulier du calcul des éléments finis des comportements très divers du sol sous une fondation en fonction de la densité initiale, c'est-a-dire des comportements normalement consolidés et surconsolidés des sols. Dans la seconde partie, nous avons étudié quelques aspects du fonctionnement de la chaussée. L'eau joue un rôle majeur dans la vie de la chaussée, mais le mécanisme est très complexe étant donnée la présence des phases solides, liquides et gazeuses. Partie confidentielle: ensuite, nous avons abordé par le calcul les moyens de limiter la remontée des fissures des dalles de béton vers la couche de roulement, soit en ajoutant des grilles, soit en utilisant des matériaux spéciaux (colas). En dernier lieu, nous présentons les premiers résultats de l'expérimentation Colas sur le manège de fatigue de Nantes. Cette recherche a pour but de rapprocher les connaissances pratiques des ingénieurs et des résultats de calculs aux éléments finis

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Reinaldo, Raydel Lorenzo. "Análise numérica do processo de instalação de estacas de deslocamento utilizando o Método do Ponto Material." reponame:Repositório Institucional da UnB, 2015. http://dx.doi.org/10.26512/2015.09.T.19518.

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Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2015.
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A capacidade de carga de uma fundação sobre estacas é governada pelas propriedades iniciais e o estado do solo ao redor da estaca depois da instalação desta. As estacas de deslocamento, durante sua instalação, modificam as tensões e a densidade do solo e, portanto o seu estado. No entanto, esta mudança das propriedades e do estado do solo ainda não é bem conhecida. Neste trabalho utilizou-se o método numérico chamado Método do Ponto Material para simular o processo de instalação de estacas. Para isto foi primeiramente estudado e validado o código NairnMPM que se baseia nesse método numérico. Algumas implementações precisaram ser realizadas no código para simular materiais com comportamento mais parecido com o solo. Foram implementados e validados os modelos constitutivos Cam Clay modificado e Subloading Cam Clay. Para a validação do código numérico e dos modelos implementados no caso da cravação de estacas foram realizados várias simulações. Na primeira delas, o processo de cravação de uma estaca em condições não drenadas foi simulado e comparado com o método de trajetória de deformações superficiais (SSPM), posteriormente foi realizada a simulação de um ensaio a escala reduzida da cravação de uma estaca em areia seca. Além destes, foi realizada a simulação de um ensaio em centrífuga da cravação de uma estaca em areia seca. De forma geral, as validações realizadas mostram a capacidade da ferramenta numérica de simular o processo de cravação da estaca e as variações de tensões que surgem no contorno desta. No final, foi realizada uma análise paramétrica do processo de cravação de estacas e obtiveram-se conclusões sobre os fatores que mais influenciam neste processo. Por fim, conclui-se que as análises do processo de instalação de estacas podem levar a projetos otimizados, uma vez que estas análises conseguem capturar fenômenos que não são observados quando as análises partem da estaca já introduzida no solo.
The bearing capacity of a deep foundation is controlled by the initial properties of the soil and the state of the soil after the installation of the pile. During its installation, displacement piles modified the stresses and the density of the soil. As a consequence, the state of the soil is modified as well. However, the way in which the properties and the state of the soil are modified is still not well known. This problem involves complex boundary conditions avoiding the development of analytical solutions. Numerical methods are a useful alternative to face this problem. In this work, the Material Point Method was the numerical method used for the simulations of the pile installation. Simulations were made using the NairnMPM code, which is based on the Material Point Method. The code was firstly validated using benchmarks available on literature. In order to simulate the behavior of soil, the Modified Cam Clay model and the Subloading Cam Clay model were implemented and validated. To validate the numerical code and the implemented constitutive models for the case of pile installation, some simulations were done. In the first one, a pile drive in undrained conditions was simulated and compared to the Shallow Strain Path Method. After that, a small scale pile drive test in dry sand was simulated. In addition, a pile drive centrifuge test in dry sand was simulated. In general, the validations show the capacity of the numerical tool to simulate the pile drive process and the stress variations that arise in the pile boundary. A parametric analysis of the pile drive was done and some conclusions about the factors affecting this processes were obtained. Finally, it was concluded that the analysis of the pile installation may lead to optimizing projects since this analysis captures features that cannot be observed when the analysis began with the pile introduced in the soil.

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TAKAINE, Toshihiro, 和憲水野, Kazunori MIZUNO, 雅幸大野, Masayuki OHNO, 利弘野田, Toshihiro NODA, 英司山田, Eiji YAMADA, and 敏浩高稲. "パイルド・ラフト基礎が設置された地盤の水～土連成弾塑性変形解析." 土木学会, 2000. http://hdl.handle.net/2237/8655.

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野田, 利弘, Toshihiro NODA, むつみ田代, Mutsumi TASHIRO, 敏浩高稲, Toshihiro TAKAINE, 顕. 浅岡, and Akira ASAOKA. "沈下低減と荷重分担に着目したパイルドラフト敷設地盤の変形解析." 土木学会, 2005. http://hdl.handle.net/2237/8610.

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Jeyakanthan, Velautham Engineering &amp Information Technology Australian Defence Force Academy UNSW. "Electro-osmotic stabilisation of soft soils : a numerical approach." Awarded by:University of New South Wales - Australian Defence Force Academy. Engineering & Information Technology, 2009. http://handle.unsw.edu.au/1959.4/44101.

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A numerical formulation for two-dimensional electro-osmotic consolidation in soft clays was derived from the basic equations of fluid flow, current flow and virtual work law. And, a well known elasto-plastic soil model, Modified Cam Clay was embedded into the formulation and implemented into the finite element program AFENA. The formulation was evaluated by comparing the predicted settlement and pore water pressure response with the values obtained from laboratory tests. The tests were conducted in an electro-osmotic triaxial apparatus, which was modified from a standard triaxial apparatus to facilitate electro-osmotic consolidation and required measurements. A series of electro-osmotic consolidation tests under different initial stress conditions were conducted to evaluate the finite element model and very good agreements between the observed and predicted results were observed. Another set of electro-osmotic tests were conducted with the similar initial stress, but different boundary conditions to examine the effects of electrochemical changes during the electro-osmosis. The study showed an apparent increase in the preconsolidation pressure and alteration in the coefficient of consolidation as a result of the electrochemical changes. A one-dimensional electro-osmotic consolidation problem was simulated and analysed, and the settlement and pore water pressure responses were compared with the solutions obtained from Esrig's (1968) one-dimensional theory. Another problem involving combined electro-osmotic and direct loading consolidation was also analysed and the results were compared with the solutions obtained from Wan and Mitchell's (1976) theory. Excellent matches were observed in both cases mentioned above for constant values of electro-osmotic and hydraulic permeabilities. However, the effects of varying electro-osmotic and hydraulic permeabilities, which are practically far more significant and not adopted in the theories mentioned above, were also analysed and the results presented. An attempt was made to simulate and analyse one of the successful field trial of electro-osmotic stabilisation conducted by Bjerrum et al (1967) on Norwegian quick clay. Good agreement between the predicted and reported settlement was observed for the first 50days of the treatment period. However, the model over-predicted the settlement after this period and the possible causes for this variation are discussed.

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Silva, Adriano Frutuoso da. "Análises tridimensionais de barragens de enrocamento com face de concreto com objetivo de otimizar os critérios de projeto." reponame:Repositório Institucional da UnB, 2007. http://repositorio.unb.br/handle/10482/1582.

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Tese (doutorado)—Universidade de Brasília, Faculdade de Tecnologia, Departamento de Engenharia Civil e Ambiental, 2007.
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As barragens de enrocamento com face de concreto (BEFC) têm sido construídas com freqüência crescente em todo mundo. Apesar disso, os critérios de projeto são ainda predominantemente empíricos baseados na experiência prática obtida de obras já construídas. A utilização da análise numérica ainda não é uma ferramenta usual para o desenvolvimento e dimensionamento desse tipo de barragem. Visando reduzir o empirismo dos projetos, a presente pesquisa propõe uma metodologia para análise do comportamento de BEFC e dimensionamento estrutural da laje, baseada nos seguintes aspectos: análise numérica tridimensional de todas as fases de projeto da barragem (construção, enchimento e rebaixamento); comportamento conjunto do maciço e face de concreto; elemento de interface para representar o contato entre essas estruturas; simulação separada da laje com elementos de placas sobre base elástica, usando coeficientes de recalque calibrados a partir das análises numéricas para fase de enchimento. Para validação dessa metodologia foi feita uma análise da barragem Barra Grande. Nessas análises, o enrocamento foi modelado com modelo elastoplástico Cam-Clay modificado, a laje com o modelo elástico linear e a interface foi representada por um modelo elástico-perfeitamente plástico com critério de ruptura de Drucker-Prager. Os resultados permitiram observar a influência do processo construtivo, das condições de contorno impostas na interface maciço-ombreira e da mudança de inclinação do talude da ombreira no comportamento da barragem e da laje, resultando em um dimensionamento da laje mais otimizado em termo de taxa de armadura. Portanto, este trabalho apresenta-se como mais um avanço no sentido de propiciar projetos de BEFC mais elaborados, baseados em fundamentos técnicos racionais. _________________________________________________________________________________ ABSTRACT
Concrete Face Rockfill Dams (CFRD) have been constructed with increasing frequency all around the world. However, design criteria still are mostly empirical and based on practical experience obtained during the construction of this type of dam. The use of numerical analyses is not yet a usual tool in the development and design of CFRD. Aiming to reduce the design empiricism, this research proposes a methodology to analyze the CFRD behavior and to design the structural concrete face, based on the following aspects: three-dimensional numerical analysis of all design phases (construction, reservoir filling and rapid drawdown); associated analysis of the concrete face and the rockfill dam mass; interface element to represent the contact between these structures; separated analysis of concrete face with plate elements over an elastic bases, using settlement coefficients calibrated from the numerical analysis during reservoir filling phase. The methodology was validated using Barra Grande Dam as a case study. In these analyses, the rockfill was simulated with the Modified Cam- Clay elastoplastic model, the concrete face with a linear elastic model and the interface represented by an elastic-perfectly plastic model with the Drucker-Prager failure criterion. The results highlight the influence of the construction process, imposed boundary conditions on the shoulders interface and the changes in shoulder slope on the whole dam behavior, resulting in an optimized concrete face design regarding the rate of steel reinforcement. Therefore, this research represents a contribution to CFRD design, based on a rational technical framework.

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Krishna, Y. S. R. "Numerical Analysis Of Large Size Horizontal Strip Anchors." Thesis, Indian Institute of Science, 2000. http://hdl.handle.net/2005/207.

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Structures like transmission towers, tele-communication masts, dry-docks, tall chimneys, tunnels and burried pipelines under water etc are subjected to considerable uplift forces. The net effect of external loading on the foundations of these structures results in forces that try to pull the foundations out of the ground. Anchors are usually provided to resist such uplift forces. Earlier theoretical research of anchor behavior has focused on elastic response and ultimate pullout capacity. Many investigators have proposed techniques for determining the collapse load of anchors. Essentially the approaches involve the use of limit equilibrium concepts, with some assumptions regarding the shape of the failure surface and/or the influence of the soil above the anchor. The possible effect of dilatency and initial stress state are not considered in these methods. A number of investigators have used the results of small size model anchors to understand the behavior and extrapolated the results for predicting the behavior of large sized anchors. This has lead to unsatisfactory results. It has been clearly shown by Dickin (1989) that the failure displacements and load displacement curve patterns are very different for small and large sized anchors, i.e. they are not just proportional to the size of the anchor. Critical pullout load and the load displacement behavior are required for the complete analysis of anchor foundations. Though, many theories have been proposed to predict the uplift capacity within the limits of accuracy required at engineering level, at present no simple rational method is available for computing deformations. In the present investigation attempts have been made to analyze the load deformation behavior of large size strip anchors in sands, clays and layered soils using two-dimensional explicit finite difference program FLAG (Fast Lagrangian Analysis of Continua), well suited for geomaterials, by assuming soil to be a Mohr-Coulomb material in the case of sands and modified Cam-clay material in the case of clays. It is now well understood that the shearing resistance of a granular soil mass is derived from two factors frictional resistance and the dilatency of the soil. So the peak friction angle can be divided in to two components critical friction angle Фcv and dilation angle Ψ. Critical friction angle is the true friction angle as a result of frictional resistance at interparticle level when the soil is shearing at constant volume. If Фcv for a given soil remains constant, the value of Ψ has to increase with the increase in initial density of soil packing. The dilatency of a soil mass gradually decreases with continued shearing from its initial high value to zero after very large shear strains, when the soil finally reaches a constant, steady volume at critical states. Correspondingly the observed friction angle Ф reduces from its peak value to Фcv at a very large strain. In earlier days, clays used to be characterized by the strength parameters c and Ф. often, under undrained conditions, Ф would be even considered zero. But in the recent developments, it is understood that all the strength of clays is frictional. There is nothing like cohesion. The part of shear strength, which appears to be independent of normal stress, is shown to be the effect of over-consolidation and the resulting dilation. Thus although Cam-clay model uses zero cohesion for all clays, it reflects this component of strength through over-consolidation and in a more realistic way. Hence, it is appropriate to consider the pre-consolidation pressure as parameter in the analysis. More specifically, the various aspects covered in this investigation are as follows. Chapter 1 provides the general introduction. In chapter 2, the existing literature for the analysis of anchors for both experimental and analytical investigations on the pullout capacity of anchors in homogeneous and layered soils and the load deformation behavior of anchors under pullout are briefly reviewed. Chapter 3 deals with the features and the implementation of the two-dimensional explicit finite difference program, Fast Lagrangian Analysis of Continua (FLAC) and the constitutive modeling of soils. It discusses the background and implementation of Strain softening / hardening model. This model is based on the Mohr- Coulomb model with non-associated shear and associated tension flow rules. In this model the cohesion, friction, dilation and tensile strength may harden or soften after the onset of the plastic yield. Further the critical state concepts and implementation of the modified Cam-clay model have been discussed. Cam-clay model originally developed for clays reflects the hydrostatic pressure or density dependent hardening material response. Chapter 4 focuses on the analysis of load deformation behavior of large size anchors in granular soils. Two-dimensional explicit finite difference program (FLAC) is used for the simulations and the soil is modeled as a Mohr-Coulomb strain softening/hardening material In this chapter a series of simulations have been carried out on large size anchor plates, with parametric variation. By analyzing these results, a generalized load deformation relationship for different sizes of anchors and different types of soil have been proposed. The results are presented in the form of influence/design charts which can be used in hand calculations to obtain an estimate of anchor capacity and deformation for a wide range of soil types and size of anchors. Chapter 5 deals with the analysis of the drained and undrained behavior of large size horizontal strip anchors in clays using modified Cam-clay model. Earlier investigators have studied the undrained behavior of anchor plates in clays, but no studies are reported in literature for the drained behavior of anchors in clays. Further it is not clear whether, drained or undrained condition will be critical for an anchor. In this chapter the drained and undrained behavior of large size anchor plates in both normally consolidated and over-consolidated states have been made. It has been found that the undrained pullout capacity of an anchor in a soil of normally consolidated state will always be more than the drained capacity. This is contrast to the usual understanding that undrained behavior is more critical than the drained behavior. In Chapter 6 an attempt has been made to analyze the behavior of large size anchors in two layered sands and in conditions where backfill material has a higher or lower strength than the native soil, for different shape of excavations. Soil is assumed to be a Mohr-coulomb strain softening/hardening material. In Chapter 7 the entire investigation covered in earlier chapters has been synthesized and some specific conclusions have been highlighted.

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TAKAGI, Kenji, 光夫野津, Mitsuo NOZU, 利弘野田, Toshihiro NODA, 敏浩高稲, Toshihiro TAKAINE, and 健次高木. "水～土連成計算を用いた砂杭拡径による砂地盤の締固めメカニズムの一考察." 土木学会, 2001. http://hdl.handle.net/2237/8642.

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Gluckman, Amie. "Minoan Barbotine Ware: Styles, Shapes, and A Characterization of the Clay Fabric." Master's thesis, Temple University Libraries, 2015. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/337064.

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Art History
M.A.
This paper examines the styles, shapes, and chemical composition, and ceramic fabric of Minoan Barbotine Ware. During the Middle Minoan period, Barbotine Ware exemplifies the creative ingenuity of the Minoan potter. The vessels’ elaborate decorative motifs play an integral part in the development of Minoan pottery. Barbotine Ware remains an ill-defined tradition. This paper will analyze the styles and shapes of Barbotine Ware vessels, as well as provide a chemical and petrographic study of Barbotine Ware from Kommos. The ultimate goal is to provide a thorough study of all aspects of the Ware in the hopes that future scholars may better understand its place within Minoan pottery and appreciate how it exemplifies the spirit of experimentation during the Middle Bronze Age on Crete.
Temple University--Theses

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Ichinose, Livia dos Santos. "Desenvolvimento e validação de método analítico indicativo de estabilidade por CLAE-DAD-CAD para besilato de anlodipino e seus produtos de degradação." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/9/9139/tde-18062018-112144/.

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O presente estudo foi realizado com o objetivo de se desenvolver e validar uma metodologia analítica indicativa de estabilidade para separação e quantificação de anlodipino e seus produtos de degradação no medicamento besilato de anlodipino 5 mg por comprimido. Para tanto, realizou-se um estudo de degradação forçada, como forma de identificar os principais produtos de degradação, que podem vir a formar num estudo de estabilidade, bem como estabelecer possíveis rotas de degradação. Foi utilizada a técnica instrumental de separação, cromatografia a líquido (CL), com dois tipos de detectores: arranjo de diodos (DAD) e corona CAD (Detector de aerossol carregado), coluna cromatográfica Zorbax SB-Phenyl 1,8µm 4,6 x 50 mm Agilent® e fase móvel constituída por tampão pH3,0, metanol e acetonitrila sob condições de gradiente (75% de tampão pH 3,0, 15% de metanol e 10% de acetonitrila; no tempo de 10 minutos tem-se 20% de tampão pH3,0, 60% de metanol e 20% de acetonitrila; no tempo de 13 minutos tem-se 75% de tampão pH3,0, 15% de metanol e 10% de acetonitrila; e no tempo de 15 minutos tem-se 75% de tampão pH3,0, 15% de metanol e 10% de acetonitrila); fluxo de 1,0mL/min até 10 minutos; de 10,1 a 13 minutos tem-se fluxo de 0,5 mL/min; e de 13,1 a 15 minutos volta ao fluxo de 1,0 mL/min; e detecção em 238 nm. O método apresentou-se linear, preciso, exato, robusto e seletivo, e proporcionou resultados confiáveis, sem interferência de degradantes e impurezas.
This study was conducted in order to develop an analytical methodology indicative of stability for separation and quantification of the antihypertensive amlodipine and its degradation products in the drug amlodipine besylate 5 mg per tablet. For this development was performed a forced degradation study, in order to identify the main degradation products that may form in a stability study, as well as establish possible degradation routes. It was used the instrumental separation technique, liquid chromatography (LC) with two types of detectors: diode array (DAD) and corona CAD (Charged Aerosol Detector), chromatographic column Zorbax SB-Phenyl 4.6 x 50 mm 1,8µm Agilent® and mobile phase of buffer pH3,0, methanol and acetonitrile under gradient conditions (75% buffer pH3,0, 15% methanol and 10% acetonitrile; 10 minutes has 20% buffer pH3,0, 60% methanol and 20% acetonitrile; 13 minutes has become 75% of buffer pH3,0, 15% methanol and 10% acetonitrile; and 15 minutes has become 75% of buffer pH3,0, 15% methanol and 10% acetonitrile); flow 1.0 mL/ min up to 10 minutes; a flow 0,5 mL/min is obtained from 10,1 to 13 minutes; and from 13,1 minutes the flows returns to 1,0 mL/min; and detection in 238 nm. The method is linear, precise, accurate, robust and selective, and provided reliable results without interference from degradation products and impurities.

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Callahan, David P. "THE WAR OF THE GIANTS: THE PRESIDENTIAL ELECTION OF 1824 AND THE RESHAPING OF AMERICAN POLITICS." Diss., Temple University Libraries, 2017. http://cdm16002.contentdm.oclc.org/cdm/ref/collection/p245801coll10/id/478463.

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History
Ph.D.
Often mischaracterized as a sedate, muddled, and issueless personality contest, the U.S. presidential election of 1824 actually proved an important transitional contest between the First and Second American Party Systems. The five very active candidates involved in the contest created dynamic organizations, sponsored energetic newspaper networks, staged congressional legislative battles, and spread vicious personal attacks against each other, presaging the tactics of the more-celebrated succeeding 1828 election. Four key developments determined the outcome of the 1824 contest. One, the decline of the opposition Federalists encouraged the Republican Party to fracture into five competing candidacies. Two, Secretary of War John C. Calhoun's vicious political attacks fatally undermined the campaign of frontrunner Treasury Secretary William H. Crawford. Three, political outsider General Andrew Jackson successfully equated the practice of politics with corruption, capturing a plurality of the popular vote by running against Washington politicians. Four, Secretary of State John Quincy Adams' superb insider deal-making ability undergirded his successful effort to win the required House election once no candidate received a majority of electoral votes from the popular election. While adversely affecting the political careers of all the participants except Jackson, the election of 1824 accelerated the ongoing trend toward democratized presidential elections and helped give birth to the Second American Party System.
Temple University--Theses

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Zhuge, Jinfeng. "PROCESSING, OPTIMIZATION AND CHARACTERIZATION OF FIRE RETARDANT POLYMER NANOCOMPOSITES." Master's thesis, University of Central Florida, 2010. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/4246.

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Fiber reinforced polymeric composites (FRPC) have superior physical and mechanical properties, such as high specific strength, light weight, and good fatigue and corrosion resistance. They have become competitive engineering materials to replace conventional metallic materials in many important sectors of industry such as aircraft, naval constructions, ships, buildings, transportation, electrical and electronics components, and offshore structures. However, since FRPC contain polymer matrix, the polymer composites and their structures are combustible. FRPC will degrade, decompose, and sometimes yield toxic gases at high temperature or subject to fire conditions. The objective of this study is to design and optimize fire retardant nanopaper by utilizing the synergistic effects of different nanoparticles. A paper-making technique that combined carbon nanofiber, nanoclay, polyhedral oligomeric silsesquioxanes, graphite nanoplatelet, and ammonium polyphosphate into self-standing nanopaper was developed. The fire retardant nanopaper was further incorporated into the polymer matrix, in conjunction with continuous fiber mats, through resin transfer molding process to improve fire retardant performance of structural composites. The morphology, thermal stability, and flammability of polymer composites coated with hybrid nanopaper were studied. The cone calorimeter test results indicated that the peak heat release rate of the composites coated with a CNF-clay nanopaper was reduced by 60.5%. The compact char material formed on the surface of the residues of the CNF-clay nanopaper was analyzed to understand the fire retardant mechanism of the nanopaper. The financial support from Office of Naval Research is acklowdged.
M.S.
Department of Mechanical, Materials and Aerospace Engineering;
Engineering and Computer Science
Mechanical Engineering MSME

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Quiñónez, Samaniego Rubén Alejandro. "Estabilização de um solo dispersivo com adição de cal." reponame:Biblioteca Digital de Teses e Dissertações da UFRGS, 2015. http://hdl.handle.net/10183/127864.

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Argilas dispersivas, também conhecidas como solos altamente erosivos, são dispersas na presença de água relativamente pura, tal como a causada por precipitações. Esse fenômeno é gerado pela ação que à água intersticial presente no solo ter uma maior concentração de cátions do que a água pura de chuva. A adição de cal nestes solos, é uma técnica de melhoramento das características físicas nas argilas dispersivas, assim também como suas propriedades mecânicas. A presente pesquisa tem por objetivo quantificar a influência isolada de cada variável; quantidade de cal, porosidade e tempo de cura, sobre a resistência não confinada de um solo dispersivo tratado com cal e permitir avaliação da transformação para um estado não-dispersivo. Esta dissertação visa a compreensão dos parâmetros-chave da mistura de argila dispersiva com adição de cal para o controle das resistências à compressão simples (qu) e de tração (qt). Assim, mostra-se que a relação vazios/cal é um parâmetro adequado para avaliar estas resistências não confinadas. Em consequência, verificou-se uma única relação qt=qu igual a 0,136, sendo independente da relação vazios/cal e o tempo de cura. Além disso, verificou-se que a metodologia para previsão de Envoltórias de Mohr-Coulomb é adequada para a determinação dos parâmetros de resistência. Finalmente, desde um enfoque ambiental através da ferramenta de avaliação do ciclo de vida (ACV) foram avaliadas todas as misturas em função ao custo energético envolvido (energia incorporada). Esta avaliação foi realizada através de um comparativo em Mega Joules por metro cúbico de mistura [MJ=m3].
Argilas dispersivas, também conhecidas como solos altamente erosivos, são dispersas na presença de água relativamente pura, tal como a causada por precipitações. Esse fenômeno é gerado pela ação que à água intersticial presente no solo ter uma maior concentração de cátions do que a água pura de chuva. A adição de cal nestes solos, é uma técnica de melhoramento das características físicas nas argilas dispersivas, assim também como suas propriedades mecânicas. A presente pesquisa tem por objetivo quantificar a influência isolada de cada variável; quantidade de cal, porosidade e tempo de cura, sobre a resistência não confinada de um solo dispersivo tratado com cal e permitir avaliação da transformação para um estado não-dispersivo. Esta dissertação visa a compreensão dos parâmetros-chave da mistura de argila dispersiva com adição de cal para o controle das resistências à compressão simples (qu) e de tração (qt). Assim, mostra-se que a relação vazios/cal é um parâmetro adequado para avaliar estas resistências não confinadas. Em consequência, verificou-se uma única relação qt=qu igual a 0,136, sendo independente da relação vazios/cal e o tempo de cura. Além disso, verificou-se que a metodologia para previsão de Envoltórias de Mohr-Coulomb é adequada para a determinação dos parâmetros de resistência. Finalmente, desde um enfoque ambiental através da ferramenta de avaliação do ciclo de vida (ACV) foram avaliadas todas as misturas em função ao custo energético envolvido (energia incorporada). Esta avaliação foi realizada através de um comparativo em Mega Joules por metro cúbico de mistura [MJ=m3].

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Leal, Ana Maria. "Conditioning of Manila clam broodstock on natural and artificial diets." Thesis, Bangor University, 1994. https://research.bangor.ac.uk/portal/en/theses/conditioning-of-manila-clam-broodstock-on-natural-and-artificial-diets(0ec43f18-fa32-4d46-9dab-e8e7ea2979ee).html.

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Two trials in 1991 and another two in 1992 were carried out on the broodstock conditioning of Manila clams, Tapes philippinarum. The main objective was to manipulate the lipid and polyunsaturated fatty acid content of Manila clam eggs by maintaining broodstock in different dietary regimes. The second objective was to assess dried algae as alternative diets for conditioning broodstock. Clams were brought into the laboratory from the natural environment early in the year, before gametogenesis had started. Supplements of cultured live (Dunaliella tertiolecta, Skeletonema costatum, Tetraselmis suecica and Isochrysis galbana) and dried algae (T. suecica) diets were fed to the broodstock, usually in a range of mixed diets, at rations equivalent to 3% or 6% of the initial dry meat weight of the broodstock in dry weight of algae per day. The microalgae differed in their long-chain polyunsaturated fatty acid content (PUFA). Unfed control clams received only the organic material which remained in the sea water after sand filtration. The nutritional value of these diets in relation to gametogenesis, fecundity, quality of eggs, and viability and growth of larvae were assessed. Dry T. suecica was the same food value as live T. suecica but Manila clams produced more eggs if supplements of live algae were added. The requirement for conditioning Manila clams (32 mm shell length) to spawn with live or dry T. suecica+S. costatum was 500 to 700 "day-degrees" (D°). With dry T. suecica on its own or mixed with I. galbana, S. costatum and D. tertiolecta it was 500 to 600 Do (44 mm shell length). In one trial clams spawned in the tanks (equivalent to 462 Do) before the first attempt to spawn them was made. Successful spawning was dependent on the quantity and quality of the algal diet during gametogenesis. With a 6% food ration, clams fed dry T. suecica+S. costatum or dry T. suecica+l. galbana produced the highest number of eggs (an average of 3.2 and 4.5 million eggs per female, respectively). The average fecundity was 83% lower when the diet was reduced to a 3% food ration. The dry meat weight, condition index and fecundity of fed broodstock were significantly higher than for unfed animals. The quantity of lipid in the eggs, usually between 4 and 9 ng egg-1, was similar whatever the broodstock diet. However, levels of the essential polyunsaturated fatty acids 20: 5w3 and 22: 6w3 in the eggs were low if the broodstock diet was deficient in these PUFAs. Even though diet manipulation caused changes in the fatty acid composition of the eggs, growth and survival of Manila clam larvae was not reduced in a hatchery situation.

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Torres, Montesinos Sergio Feliciano, and Alarcon Jacques Yitzhak Landa. "Mejoramiento de suelos arcillosos en subrasante mediante el uso de cenizas volantes de bagazo de caña de azúcar y cal en el tramo de la carretera Tingo María - Monzón en la provincia de Leoncio Prado." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2020. http://hdl.handle.net/10757/653977.

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El presente trabajo de investigación tiene como fin determinar el porcentaje optimo del uso del material estabilizante, compuesto por la Ceniza de Bagazo de Caña de Azúcar (CBCA), y cal, con un enfoque económico y efectividad de uso en tanto a mejora del porcentaje de CBR de la subrasante clasificada como pobre o inadecuada. Dentro del marco de desarrollo del trabajo se encuentra el estudio de la influencia de la Ceniza de Bagazo de Caña de Azúcar (CBCA) en el suelo natural, del mismo modo que la cal; esto para entender los cambios en las propiedades físicas y mecánicas de la mezcla. El suelo en estudio es un suelo arcilloso de baja plasticidad según SUCS, y según AASHTO un A-6(8); este mezclado con 5%, 15% y 25% de Material Estabilizante respecto a la masa seca, con combinaciones, 100% CBCA, 75%CBCA y 25%Cal, 50%CBCA y 50%Cal, 100%Cal. Todas las Combinaciones especificadas se ensayaron para Proctor y CBR, y luego se analizaron cada uno de los resultados mediante un diagrama de Líneas para los dos ensayos. La proporción de material estabilizante es el 5% respecto a la masa seca de arcilla que presenta la mejora eficiente e inmediata el CBR, aumentando en un 110.81% respecto a la del suelo natural, y la densidad, aumentando en 54.7% respecto al suelo natural. Este porcentaje está compuesto por la combinación parcial de 50% de Cal y 50% de CBCA seleccionada con fines económicos, con la reducción de aplicación de cal.
The aim of this research work is to use agroindustry’s wastes in conjunction with traditional stabilizers, such as lime, to solve the problem of unpaved roads with poor or inadequate subgrade according to their CBR value. The fundamental objective of this research work was to study the influence of Sugar Cane Bagasse Ash (CBCA) in conjunction with Lime to enhancement the mechanical properties of low plasticity clay soils, according to AASHTO a A-6 (8) sub group’s soil. Likewise, some tests that were carried out in the research were the AASHTO standard compaction tests and CBR, to compare the natural soil sample and the global combinations 5%, 15% and 25% of Stabilizing Material applied to the natural soil, containing each of these the next four proportions (100% CBCA, 75% CBCA and 25% Cal, 50% CBCA and 50% Cal, 100% Cal). Among the most noteworthy results were soil improvements in compaction and CBR characteristics, reducing the incidence of Lime by 50%. The proportion of stabilizing material that presents the immediate and efficient enhancement is obtained with 5% Stabilizing Material, respect to the clay’s dry mass; with a partial combination of 50% of Lime and 50% of CBCA, increasing the CBR by 110.81% with respect to the natural soil’s CBR.
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Vizcarra, Arapa Santiago, and Cabrera Ismael Lorenzo Lujan. "Análisis experimental de las características mecánicas de la subrasante arcillosa del camino vecinal N° SM-707 Tarapoto – San Francisco de Río Mayo estabilizada con 3% de cal tras la adición de Cenizas de Cáscara de Arroz (CCA)." Bachelor's thesis, Universidad Peruana de Ciencias Aplicadas (UPC), 2021. http://hdl.handle.net/10757/656757.

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Existen estudios sobre las mejoras mecánicas que le brinda la adición de cal y Ceniza de Cáscara de Arroz (CCA) a los suelos arcillosos -naturalmente plásticos- con más de 70% de material fino en su composición. Sin embargo, para el comportamiento de arcillas arenosas, cuyo porcentaje de granos gruesos en su estructura superan el 40%, hacen falta más referencias. En la investigación se evalúa la influencia de la adición de CCA a esta clase de suelo, estabilizado con 3% de cal. El suelo estabilizado (sin CCA) incrementó 11.2 veces su valor de CBR natural; al agregarle la adición, el CBR incrementó solo en 1.56%. Al adicionarle 28% de CCA se observó un decrecimiento en su resistencia. Por otro lado, según la clasificación AASHTO, la trabajabilidad del suelo estabilizado fue mejorando a medida que se incrementó la adición de CCA, llegando a valores de IG=0. La mejor performance del suelo estabilizado se obtuvo con 16% de CCA, alcanzando 51.3% de CBR, 1.65g/cm3 de MDS y 15.8% de OCH. El CBR de este suelo estabilizado con cal y con la adición de CCA no proyecta mejoras mecánicas sustanciales, por más que demuestre una mejor trabajabilidad, la estabilización con cal de este tipo de suelos resulta suficiente para una buena performance.
There are many studies about how the addition of lime and Rice Husk Ash (RHA) gives the soil a better mechanical behavior, particularly on clayey soils, where usually fine particles reach more than 75%. However, the soils with a small presence of fine particles (59-60%) do not have much research. This investigation evaluates the influence that RHA has on this kind of soil previously stabilized with 3% of lime. After the initial mix of soil-lime, the CBR increased 11.2 times its initial value; within the addition of the ash, the CBR maxed out its value increasing just 1.56%. When 28% of RHA was added, a decay in the value of CBR was noticed. Otherwise, soil workability improved and following the AASHTO standards, the specimens with more ash resulted in a more granular material, with a group index value of 0. The greatest CBR record was obtained when the stabilized soil was added a 16% RHA, reaching a 51.3% CBR, 1.58g/cm3 of MDD and 16.5% of OMC. The CBR of the soil stabilized with lime and the addition of RHA, does not shows substantial improvement, and beyond that the workability seems better, the addition of lime by itself should be enough for an adequate performance for silica-rich clayey soils.
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Bandeira, Raquel Duarte da Costa Cunha. "Desenvolvimento e valida??o de metodologia na detec??o e quantifica??o de Ocratoxina A no caf? verde e torrado utilizando a t?cnica cromatografia l?quida acoplada a espectrometria de massas aplicando os conceitos da metrologia qu?mica." Universidade Federal Rural do Rio de Janeiro, 2010. https://tede.ufrrj.br/jspui/handle/jspui/2349.

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Coffee is an extremely complex food matrix and has an important role in the world?s economy, especially in producing and exporting countries like Brazil. However this product may suffer from technical barriers imposed for exportation because of the possible presence of ochratoxin A, which is nefrotoxic and carcinogenic mycotoxin found in many foods including coffee. The aim of this study was to implement chemical metrology concepts in the development and validation of Liquid Chromatography with Mass Spectrometry in tandem (CLAE-EM/EM) method for identification and quantification of ochratoxin A in green and roasted coffee estimating uncertainty of measurement according to directive 2002/657/EC and Inmetro guidelines (DOC-CGCRE-2010). The extraction method was based on Pittet (1998) and chromatographic parameters were: flow rate of 0.3 mL/min, mobile phase 80:20 water trifluoracetic acid 0.05 %: methanol trifluoracetic acid 0.05 %, injection volume of 50 PL, injection mode Full loop, isocratic mode. The column was Synergi Hydro C18. The mass spectrometry parameters were optimized and transitions selected based on the colision energies monitored were m/z 404 >358 (-10.5 V) and m/z 404 >239 (-20.5 V). From the validation procedure, methods were considered seletive. The evaluation and verification of matrix effect was performed by comparing variances and averages using F and t test. Value of Fcalculated for green coffee (25.2152) and roasted coffee (104.0353), were higher than Ftable (4.0426). Value of t calculated for green (5.0214) and roasted coffee (10.1997) were higher than ttable (2.0106). Both methods were considered linear in the working range of calibration curve with linear correlation coefficients (r) of 0.98188 and 0.91754 for green and roasted coffee, respectively.The quantification and detection limits were 1.2 Pg/kg and 3.0 Pg/kg; 0.36 Pg/kg and 1.0 Pg/kg, for green and roasted coffee respectively. The average recoveries, RSDr and RSDR were in range of 90.45 ? 108.81 %, 5.39 ? 9.94 % and 2.20 ? 14.34 % for green coffee and 89.02 ? 108.85 %, 2.43 ? 13.73 % and 12.57 ? 17.84 % for roasted coffee. All results obtained were considered within acceptable levels according to literature. Measurement value and expanded uncertainties (U) for ochratoxin A were mass fraction w = (11.50 ? 1.11) and w = (4.63 ? 0.63) for green coffee and roasted coffee. Both methods developed and validated using a high sensitivity technique, that allowed detection, confirmation and quantification of ochratoxin A in green and roasted coffee with a estimated uncertainty of measurement, and in the future these methods can be used to help overcome possible technical barriers imposed for exportation of Brazilian coffee.
O caf? constitui uma matriz extremamente complexa e tem importante papel na economia mundial, especialmente nos pa?ses produtores e exportadores como o Brasil. No entanto tem sido alvo de barreiras t?cnicas devido a uma subst?ncia denominada ocratoxina A, micotoxina potencialmente nefrot?xica e nefrocarcinog?nica encontrada em muitos alimentos inclusive o caf?. O presente trabalho tem como objetivo implantar os conceitos da metrologia qu?mica no desenvolvimento, e valida??o do m?todo para identifica??o e quantifica??o de ocratoxina A no caf? verde e caf? torrado estimando a incerteza da medi??o e utilizando a t?cnica de Cromatografia L?quida acoplada a Espectrometria de Massas em s?rie (CLAE-EM/EM) seguindo os crit?rios da diretiva EC-657/2002 e o documento orientativo do Inmetro (DOCCGCRE- 2010). A metodologia de extra??o baseou-se em Pittet (1998) e os par?metros cromatogr?ficos foram: fluxo de 0,3 mL/min, fase m?vel 80:20 ?gua ?cido trifluoroac?tico 0,05%: metanol ?cido trifluoroac?tico 0,05 %, volume de inje??o de 50 PL, com o modo de inje??o Full loop e sistema de elui??o isocr?tico. A coluna utilizada foi Synergi Hydro C18. As condi??es do espectr?metro de massas foram otimizadas e a transi??o selecionada de acordo com suas energias de colis?o foram m/z 404 >358 (-10,5 V) e m/z 404 >239 (-20,5 V). A partir da valida??o os m?todos propostos foram considerados seletivos, a avalia??o e comprova??o do efeito matriz foi realizada atrav?s da compara??o das vari?ncias e das m?dias atrav?s do teste F e teste t. O Fcalculado para o m?todo caf? verde (25,2152) e caf? torrado (104,0353), apresentaram valores maiores que o Ftabelado (4,0426). O tcalculado para o caf? verde (5,0214) e torrado (10,1997) apresentaram valores superiores ao ttabelado (2,0106). Os m?todos foram considerados lineares em toda a faixa de trabalho da curva de calibra??o com os coeficientes de determina??o linear (r) de 0,98188 e 0,91754 para matriz caf? verde e caf? torrado, respectivamente. O limite de quantifica??o e detec??o para os m?todos propostos foram de 1,2 Pg/kg e 3,0 Pg/kg para caf? verde e 0,36 Pg/kg e 1,0 Pg/kg para caf? torrado. Os valores das recupera??es m?dias, DPRr e DPRR variaram na faixa de 90,45 - 108,81 %, 5,39 - 9,94 % e 2,20 - 14,34 % para caf? verde; e de 89,02 - 108,85 %, de 2,43 - 13,73 % e 12,57 - 17,84 %, para caf? torrado. Todos os resultados obtidos encontram-se dentro dos limites comumente aceit?veis na literatura. Todos os resultados de medi??o e as incertezas expandidas (U) para ocratoxina A foram as fra??es m?ssicas W = (11,50 ? 1,11) Pg/kg e W = (4,63 ? 0,63) Pg/kg para caf? verde e caf? torrado, respectivamente. Os m?todos desenvolvidos e validados utilizaram t?cnica de elevada sensibilidade, permitindo a detec??o, confirma??o e a quantifica??o de ocratoxina A no caf? verde e caf? torrado com c?lculo da incerteza, podendo auxiliar futuramente na supera??o das barreiras t?cnicas para exporta??o do caf? brasileiro.

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Harris, Matthew Richard. "A study of the naturalisation and dispersal of a non-native bivalve, the Manila clam, Ruditapes philippinarum (Adams and Reeve 1850) in estuaries along the south coast of England." Thesis, University of Portsmouth, 2016. https://researchportal.port.ac.uk/portal/en/theses/a-study-of-the-naturalisation-and-dispersal-of-a-nonnative-bivalve-the-manila-clam-ruditapes-philippinarum-adams-and-reeve-1850-in-estuaries-along-the-south-coast-of-england(5f264944-b70d-4236-9142-5c1087a3ecbf).html.

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The Manila clam, Ruditapes philippinarum, was introduced into the British Isles in the 1980s for the purpose of aquaculture in order to take advantage of the rapid growth rate and high profitability of this non-native species. The decision to import the Manila clam, was based on the findings of a report commissioned by the Ministry of Agriculture Fisheries and Food which determined that the Manila clam would be able to be grown to marketable size faster than the local species Ruditapes decussatus, but would not be able to reproduce due to the inclement seawater temperature regime around the British Isles. Within four years of its introduction into Poole Harbour in Dorset, the Manila clam had successfully reproduced and by 2004 it had naturalised in the Harbour. This thesis sets out to determine the factors that influence reproductive and recruitment success of the Poole Harbour population of Manila clams and to determine what factors could influence the further dispersal of the Manila clam along the South and South Eastern coastline of England. The population of Manila clams at Holton Mere in Poole Harbour was quantitatively sampled on a monthly basis, with some omissions, from June 2009 until August 2012. For each sample month, the density and population dynamics of the population were estimated. From February 2010 until August 2012 the condition index of the population was estimated on a monthly basis. The population dynamics of the Holton Mere population were influenced by fishing pressure with the removal of the majority of clams over the minimum landing size of 35mm. Condition index followed a seasonal pattern with high condition in summer and low condition in winter. Recruitment success in the Holton Mere population was inconsistent, with successful recruitment events coinciding with higher levels of condition index. A study to correlate environmental parameters with clam condition index, using long term monitoring with a multi-parameter sonde were undertaken in Poole Harbour between July 2011 and July 2012. Seawater temperature and food availability was found to positively correlate with condition index. Experiments determined that predation by the European shore crab, Carcinus maenas has the potential to influence the success of recruitment events due to high levels of predation on newly settled and juvenile clams. Reduced salinities and low temperatures influence the rate of predation of juvenile Manila clams by crabs. Salinity influences behaviour in both adult and larval Manila clams, with burial by the adults and swimming in the larvae ceasing at salinities below 18psu. Manila clam larvae actively swim through haloclines into areas of reduced salinity. Manila clam larvae are able to tolerate salinities as low as 10psu for 24 hours with low levels of mortality. The Manila clams’ tolerance to reduced salinity allows it to colonise areas of marginal habitat where competition is low. Predicted increasing seawater temperatures will allow the Manila clam to extend its range northwards by causing cold water species to vacate ecological niches for the Manila clam to occupy and to improve the consistency of reproductive success. The Manila clam is now established along the Southern coastline of England and is unlikely to disappear. As such it should be classed as a naturalised species and managed in the same way as native species. The Manila clam is likely to spread northwards in the future and will provide both economic and ecological benefits in the form of new fisheries and also prey for local species including wading birds. The high growth rate and versatility of the Manila clam would allow it to be used in polyculture systems and be grown in habitats that were previously deemed unsuitable for bivalve culture.

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"Aplicação do modelo cam-clay modificado a um solo arenoso." Tese, Biblioteca Digital de Teses e Dissertações da USP, 1998. http://www.teses.usp.br/teses/disponiveis/18/18132/tde-23032007-151306/.

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Póvoa, Rui Ferreira. "Simulação do comportamento de um solo artificialmente estabilizado com o modelo Cam Clay estruturado modificado." Master's thesis, 2014. http://hdl.handle.net/10316/38462.

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Dissertação de Mestrado Integrado em Engenharia Civil apresentada à Faculdade de Ciências e Tecnologia da Universidade de Coimbra
A execução de obras de Engenharia Civil (aterros, fundações, etc.) sobre solos moles requer frequentemente a melhoria do comportamento destes solos, os quais em geral exibem elevada deformabilidade e baixa resistência ao corte. Uma das técnicas de melhoramento consiste na mistura in situ do solo natural com ligantes formando colunas de solo estabilizado, técnica designada de deep mixing. A estabilização química induzida por esta técnica origina profundas alterações face ao solo não estabilizado, sendo essas alterações justificadas pela resistência da estrutura do solo. A simulação numérica do comportamento mecânico do solo quimicamente estabilizado com ligantes requer por isso a utilização de modelos constitutivos que incluam o efeito da estrutura deste novo material. A presente dissertação é elaborada com o propósito de simular o comportamento de solos estabilizados considerando o efeito da estrutura, para se analisar as características e os aspetos mais relevantes do seu comportamento, e visando a sua interpretação nos modelos constitutivos usados para o simular. Constata-se que as ligações cimentícias tem como objetivo unir os agregados de argilas, dando continuidade à fábrica, e que os efeitos da coesão, e o processo de desestruturação dessas ligações, representam as principais características a serem incorporadas em modelação constitutiva. O modelo Cam Clay Estruturado Modificado, é descrito e implementado numa análise de elementos finitos, para se simular o comportamento do solo mole do Baixo Mondego quimicamente estabilizado com ligante, tendo as suas potencialidades sido estudadas comparando os resultados numéricos com os obtidos nos ensaios triaxiais de corte não drenado e edométricos. Conclui-se que o modelo consegue captar com êxito a influência da estrutura na caracterização da compressibilidade, na relação tensão-deformação-resistência, e na evolução qualitativa das pressões intersticiais, embora se registem importantes discrepâncias em termos quantitativos
The execution of Civil Engineering projects (embankments, foundations, etc.) on soft soils requires frequently the improvement of the behavior in these soils, which generally present high deformability and low strength. One of the improvement techniques consists on the in situ mixture of the natural soil with cement, forming stabilized soil columns, a technique called deep mixing. The chemical stabilization induced by this technique induces profound alterations compared to the non-stabilized soil, alterations justified by the resistance of soil structure. The numerical simulation of chemically stabilized with aggregates soil's mechanical behavior requires therefore the use of constitutive models that include the effect of structure on this new material. This study is elaborated with the purpose of simulating stabilized soil behavior considering the structural effect, in order to analyse the most relevant characteristics and aspects of its behavior, and focusing on their interpretation in the constitutive models used to simulate. It is noted that the cement links have the objective of joining the clay aggregates, giving continuity to the fabric, and that the cohesion effects and the destructuring process of those links represent the main characteristics to be included on the constitutive modelation. The Cam Clay Structured Modified model is described and implemented in a finite element analysis context, to simulate the Baixo Mondego soft soil behavior, chemically stabilized with aggregates, having its potentialities been studied comparing the numerical results with the obtained on the undrained triaxial shear and edometric tests. It is concluded that the model can simulate the effect of structure into compressibility and stress-strain-strength behavior, as well as, in the qualitative evolution of pore water pressure, even though, quantitatively speaking, was different

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Kurz, David. "Understanding the effects of temperature on the behaviour of clay." 2014. http://hdl.handle.net/1993/23547.

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There is a growing need to better understand the relationship between time, strain rate, and temperature on the load-deformation behaviour of clay soils in engineering applications. These applications may include: infrastructure constructed in northern regions where climate change is a growing concern; disposal of nuclear waste; and, industrial structures, such as furnaces, foundries, and refrigeration plants. Temperature variations may induce changes in internal pressure in the soil, swelling and shrinkage, and affect the mechanical properties of the soil. This thesis presents thermal numerical modeling for two instrumented field sites in northern Manitoba. Thermal conductivity testing on samples from these sites and field data are used to calibrate these thermal numerical models. Various boundary conditions are examined. The capabilities of the models are evaluated to determine if the models adequately simulate and predict changes in temperature in geotechnical structures. A discussion is presented on the strengths and weaknesses in the models and the predictive capabilities of the models. The thesis then shifts into understanding the concepts of thermoplasticity and viscoplasticity and the mathematics relating these concepts. Mathematical models that describe these concepts are examined and compared with traditional soil mechanics approaches. The concepts of thermoplasticity and viscoplasticity are combined in an encompassing elastic thermo-viscoplastic (ETVP) model using a semi-empirical framework. A sensitivity analysis is used to evaluate quantitatively the response of the model. The model is then validated qualitatively against published laboratory data. Applications of the ETVP model are discussed.

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Mirante, João Miguel Rosa Pereira. "Impulsos de terras sobre estruturas de suporte: aplicação de modelos dos estados críticos." Master's thesis, 2014. http://hdl.handle.net/10362/16079.

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Os modelos de comportamento de solos que aplicam a teoria da mecânica dos solos dos estados críticos são uma importante base para a compreensão do comportamento dos solos e uma ferramenta que permite, de uma forma simples, ter em conta aspetos do comportamento que os mo-delos muito básicos não permitem. Neste trabalho compara-se, com recurso aos programas de cálculo geotécnico PLAXIS e CRISP, a utilização de dois modelos - um elástico-perfeitamente plástico (modelo Mohr-Coulomb) e outro baseado nos estados críticos (modelo Cam-Clay Modificado) - na determina-ção das pressões e dos impulsos de terras sobre estruturas de suporte rígidas. Comparam-se também os resultados numéricos com os obtidos com métodos analíticos. Exceto para casos mais complexos (utilizando simultaneamente solo sobreconsolidado e pa-ramento rugoso), os impulsos ativos e passivos obtidos com o modelo Cam-Clay Modificado são se-melhantes aos obtidos com o modelo Mohr-Coulomb e com os métodos analíticos, concluindo-se que o modelo avançado modela satisfatoriamente a rotura do solo. Este modelo apresenta inclusive aspetos interessantes, como o desenvolvimento, em alguns casos em que se utiliza solo sobreconsolidado, de uma resistência de pico, que se evidencia no aparecimento de um impulso de pico. No entanto, na utilização do modelo deve ter-se em atenção alguns aspetos, nomeadamente a forma como se obtém o seu parâmetro de resistência, 𝑀, e o nível de deformações que se espera ser atingido, já que o impulso apresenta um pico apenas até um certo nível de deformações.

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Picard, Jean-Marc. "Écrouissage thermique des argiles saturées : application au stockage des déchets radioactifs." Phd thesis, 1994. http://pastel.archives-ouvertes.fr/pastel-00574024.

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Les argiles soumises à une charge mécanique constante et à une lente élévation de température donnent lieu généralement à une contraction irréversible. Ce phénomène est interprété par une variation des limites d'élasticité avec la température appelée écrouissage thermique. Une formulation du comportement plastique compatible avec les principes de la thermodynamique montre que ces effets de la température en plasticité reposent sur un couplage particulier où intervient la chaleur latente de transformation de l'état d'écrouissage du matériau. Une extension thermomécanique simple du modèle Cam Clay est proposée pour l'étude du comportement thermomécanique des argiles saturées. Une analyse d'essais de laboratoire déjà publiés illustre la pertinence de ces concepts. Des argiles issues de formations géologiques profondes susceptibles de recevoir un stockage de déchets radioactifs présentent un écrouissage thermique en laboratoire. Les conséquences pour un stockage sont évaluées par des modélisations et par des essais in situ menés dans un laboratoire souterrain. Les mesures faites autour d'une sonde chauffante révèlent l'importance des couplages thermohydromécaniques au sein d'un massif argileux. Les modélisations donnent une interprétation cohérente des mesures in situ. L'accent est mis sur les interactions entre les diverses phases d'un essai : excavation, reconsolidation du massif puis chauffage. Ces analyses montrent que l'écrouissage thermique se manifeste peu dans ces essais. En revanche, les couplages thermohydromécaniques de nature élastique sont nettement plus importants que ceux prévus d'après les essais triaxiaux classiques, ce que l'on attribue la raideur accrue de ce matériau lorsqu'il subit de très faibles déformations.

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Johnson, Rebecca Linn. "The quiet clam is quite calm: Foveal and parafoveal transposed -letter neighborhood effects in reading." 2007. https://scholarworks.umass.edu/dissertations/AAI3275783.

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Previous research has found that when a word like “clam” is presented at the foveal level, its transposed-letter neighbor “calm” is also activated. This activation of multiple lexical candidates causes interference in naming and lexical decision tasks. Here, four eye-tracking experiments were conducted to explore the nature of transposed-letter (TL) neighborhood effects within the context of normal silent reading. Experiments 1 and 2 addressed the processing of target words that have a transposed-letter neighbor (e.g., angel, angle) in comparison to target words that do not have a transposed-letter neighbor (e.g., alien, slope ). Furthermore, Experiment 2 manipulated the sentence context leading up to the target word to explore whether semantic constraints can attenuate neighborhood interference effects. The results indicated that readers do take longer to process words that have a TL neighbor than words that do not have a TL neighbor. This interference effect, however, disappeared when the beginning of the sentence was constraining such that only one of the two members of the TL pair was likely. While both Experiments 1 and 2 explored effects at the foveal level, Experiments 3 and 4 explored the parafoveal processing of transposed-letter neighbors by employing an eye-movement-contingent boundary change paradigm. In Experiment 3, readers received a parafoveal preview of a TL target word that was either (1) identical to the target word (e.g., calm as the preview of calm), (2) a TL-neighbor (e.g., clam) or (3) a substituted-letter (SL) control (e.g., chem). In Experiment 4, a further set of parafoveal preview conditions was explored. Across both experiments, readers' fixation durations on the target words were significantly longer when the parafoveal previews were substituted-letter nonwords than when they were TL neighbors, suggesting that TL neighbors (when presented in the parafovea) facilitate word recognition, rather than inhibit processing. Collectively, these experiments indicate that TL neighborhood interference effects do occur in normal silent reading, but these effects occur late and are influenced by sentence constraints.

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35

Salamah, Sultan. "The Effects of BAM as an Adsorptive Media on Phosphorus Removal in Stormwater." Master's thesis, 2014. http://digital.library.ucf.edu/cdm/ref/collection/ETD/id/6171.

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To maintain the quality of receiving water bodies, it is desirable to remove total phosphorus (TP) in stormwater runoff. Many media filtration technologies have been developed to achieve TP and soluble reactive phosphorus (SRP) removal. Efficient media adsorption is essential to insure control of stormwater phosphorus inputs to the receiving water body. This project develops and analyzes a functionalized Biosorption Media (BAM) to remove phosphorus species from stormwater runoff. One goal of this project is to find the BAM values for coefficients such as maximum adsorption capacity (QM: 4.35E-05) for the media through SRP isotherm equilibrium experiments using the Langmuir and Freundlich models. In addition, an upflow column experiment was also performed to study BAM nutrient removal from stormwater runoff. Finally, the information from the isotherm and the column experiments are used to estimate the life expectancy or quantity required of the media, and to define the effectiveness of BAM in phosphorus removal. The result of this study shows that BAM is a feasible stormwater treatment that can remove 60% SRP and >40% TP at temperature between 21-23°C. The media is adequately modeled by both the Langmuir and the Freundlich models over the concentration range of interest in stormwater.
M.S.Env.E.
Masters
Civil, Environmental and Construction Engineering
Engineering and Computer Science
Environmental Engineering

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36

Blais, Véronique. "Caractérisation d’un nouveau récepteur à octopamine exprimé chez la palourde Spisula solidissima." Thèse, 2009. http://hdl.handle.net/1866/3763.

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À partir des ovocytes de la palourde Spisula solidissima, un ADNc codant un récepteur nommé Spi-OAR a été cloné et séquencé. Une analyse de la séquence en acides aminés a indiqué que ce nouveau récepteur possède une forte similarité avec les récepteurs β-adrénergiques et les récepteurs à octopamine. En effet, il est étroitement lié à la classe des récepteurs à octopamine « β-adrénergique-like » couplés à une protéine Gs. L’ADNc de Spi-OAR a été introduit dans un vecteur d'expression (pCEP4) et un épitope reconnaissable par un anticorps commercial a été ajouté au segment N-terminal. Cette construction a été transfectée dans des cellules hôtes (HEK 293) et des études d’immunofluorescence ont montré une expression efficace du récepteur au niveau membranaire. Également, des mesures d'AMPc pour les cellules exprimant Spi-OAR ont révélé une augmentation de ce messager secondaire lors de l'ajout de l'octopamine, et dans une moindre mesure, la tyramine, tandis que la dopamine, la sérotonine et l'histamine n’ont engendré aucun effet. Une légère activité constitutive de ce récepteur dans les cellules hôtes a été observée. De plus, une analyse RT-PCR avec des oligonucléotides spécifiques a révélé l'ARNm de Spi-OAR non seulement dans les ovocytes, mais aussi dans les gonades, le cœur, les muscles adducteurs, les branchies et les ganglions suggérant que ce récepteur soit exprimé de façon ubiquitaire dans divers tissus et dans différents stades embryonnaires chez la palourde. En outre, des études avec des ovocytes isolés n'ont montré aucun effet de l’octopamine sur la réactivation méiotique. Des études éventuelles pourront finalement confirmer le rôle fonctionnel de Spi-OAR.
A cDNA encoding for an octopamine receptor named Spi-OAR was cloned and sequenced from the surf clam Spisula solidissima oocytes. An analysis of its predicted amino acid sequence showed a high degree of similarity with β-adrenergic and octopamine receptors. This receptor qualifies as a novel receptor closely related to the proposed class of insect octopamine « β-adrenergic–like » receptors coupled to Gs protein. This cDNA was introduced into an expression vector (pCEP4), with an added N-terminal FLAG tag sequence, and transfected in host cells (HEK 293). Immunofluorescence studies showed expression of the receptor with a proper localization to the plasma membrane. Measurements of cAMP in transfected cells revealed that addition of octopamine, and to a lower extent, tyramine induced a rise in cAMP while dopamine, serotonine and histamine had no effect. Overexpression of Spi-OAR in mammalian cells induced slight constitutive increase of cAMP. An RT-PCR analysis with specific oligonucleotides revealed the presence of the receptor mRNA not only in oocytes but also in whole gonads, heart, adductor muscle, gills and ganglia suggesting that this receptor is likely ubiquitously expressed. Expression of Spi-OAR was also detected at different embryonic stages. Despite the demonstrated expression of Spi-OAR in oocytes, octopamine had no effect on meiotic reinitiation. Further studies will examine the function of Spi-OAR.

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