Com a finalidade de estudar o comportamento de fluidos aquosos não miscíveis em água no solo, foram executados ensaios de laboratório, a construção de um modelo físico e a comparação dos dados com a simulação numérica com o programa HSSM. Os ensaios de laboratório tiveram a finalidade de obter os parâmetros do solo utilizado no modelo físico e numérico. Foram obtidas curvas de retenção do solo com concentrações de 2, 5, 10 e 15% de óleo e somente com água, para comparar o comportamento das curvas. Para o modelo físico, foi construído um tanque experimental para simular o derramamento de óleo no solo e, assim, obter uma pluma de contaminação de óleo de maneira controlada. Foram executados três ensaios com o tanque experimental, primeiro com o solo na umidade higroscópica, o segundo com um nível dágua definido, e o terceiro com o solo úmido, mas sem um nível dágua. Destes ensaios no tanque, foram coletadas amostras para a análise em laboratório das concentrações de óleo de cada parte do tanque. A partir dos resultados das curvas características foi possível observar que o óleo influencia principalmente na umidade residual. E a análise das amostras coletadas do tanque experimental indica que a concentração de óleo na pluma estava constante, com concentração de 2% de óleo. Juntando os dados colhidos dos ensaios de laboratório e do tanque experimental, foram executadas simulações da evolução da pluma de contaminação de NAPL para os três casos simulados no tanque experimental. A simulação numérica foi coerente com o modelo físico, mas foi observado que subestima a velocidade de expansão da pluma, principalmente quando o solo está com a umidade baixa. / In order to study the behavior of non-aqueous phased liquids in the soil, laboratory tests were performed, and the construction of a physical model and comparison of data obtained with the numerical simulation with the program HSSM. Laboratory tests are designed to obtain the soil parameters used in the physical and numerical model. Retention curves of soil with concentrations of 2, 5, 10 and 15% of oil and water only were obtained to compare the curves. For the physical model, an experimental tank was built to simulate the oil spill on the ground and have a contamination plume of oil with controlled conditions. Were performed three experiments with the tank, first with the hygroscopic soil moisture, the second with a defined water table, and the third with natural soil moisture, but without a water table. From these tests in the tank, samples were collected for laboratory analysis of concentrations of each part of the oil tank. From the results of the retention curves it was observed that the major oil influence was on residual moisture. And the analysis of samples collected from the experimental tank indicates that the oil concentration in the plume was constant at the concentration of 2% of oil. Combining the data collected in laboratory testing and experimental tank, numerical simulations were performed of the evolution of NAPL contamination plume for the three cases simulated in the experimental tank. The numerical simulation was consistent with the physical model, but it was observed that underestimates the rate of expansion of the contamination plume, especially when the moisture of soil is low.

O presente trabalho teve como objetivo principal a análise experimental da distribuição das ações verticais entre paredes de alvenaria estrutural com a utilização de modelo físico reduzido na escala 1:5. Precedendo a construção do modelo físico reduzido foram realizados ensaios de caracterização dos componentes e da alvenaria na escala reduzida 1:5. Os ensaios no modelo físico reduzido consistiram na inserção de carregamentos uniformemente distribuídos e aplicados em diferentes ambientes e níveis. A análise da distribuição das ações verticais foi possível devido à instrumentação realizada na base do modelo físico reduzido através de células de carga. Os resultados foram analisados comparando-se os resultados experimentais com os usuais procedimentos teóricos de distribuição das ações verticais e também com a modelagem por elementos finitos; visando, desta forma, identificar qual o procedimento que mais se aproxima dos resultados experimentais. Foi possível concluir que a modelagem por elementos finitos e o procedimento de Grupos de Paredes apresentaram resultados mais próximos dos experimentais na análise da distribuição das ações verticais. / This study had as a main aim the experimental analysis of vertical loads distribution between structural masonry walls using a reduced physical model in a 1:5 scale. Preceding the building of the physical model were performed tests in order to obtain characterization of the components and of the masonry in a 1:5 reduced scale. The tests in the reduced physical model consisted in the insertion of loads uniformly distributed and applied in different environments and levels. The analysis of the vertical loads distribution was possible due to instrumentation performed on the basis of the physical model by load cells. The results were analyzed by comparing the experimental results with the usual theoretical procedures of vertical loads distribution and also with the modeling by finite elements; aiming, this way, to identify which procedure is closer to the experimental results. It was concluded that modeling by finite elements and Walls Groups procedure showed results closer to the experimental analysis of vertical loads distribution.

<p>Combustion supervision by evaluating flywheel speed variations is a common approach in the automotive industry. This often involves preliminary measurements. An adequate model for simulating flywheel speed can assist to avoid some of these preliminary measurements. </p><p>A physical nonlinear model for simulating flywheel speed based on cylinder pressure information is investigated in this work. Measurements were conducted at Scania in a test bed and on a chassis dynamometer. The model was implemented in MATLAB/Simulink and simulations are compared to measured data. The first model can not explain all dynamics for the measurements in the test bed so extended models are examined. A model using a dynamically equivalent model of the crank-slider mechanism shows no difference from the simple model, whereas a model including a driveline can explain more from the test-bed measurements. When simulating the setups used at the chassis dynamometer, the simplest model works best. Yet, it is not very accurate and it is proposed that optimization of parameter values might improve the model further. A sensitivity analysis shows that the model is fairly robust to parameter changes.</p><p>A continuation of this work might include optimization to estimate parameter values in the model. Investigating methods for combustion supervision may also be a future issue.</p>

Sea water intake structures submerged in the surf zone are used to provide water for cooling processes in large facilities such as power plants and refineries. Structures submerged in the surf zone are subject to large forces from breaking waves. To study these forces induced from realistic sea state conditions, a physical model of an intake structure submerged in the wave breaking zone was constructed and subjected to a wide spectrum of regular and irregular waves. The model structure was designed in a manner so force measurement could be isolated to separate components of the structure. The data of peak forces on the structure was analyzed for correlations with varying irregular wave properties. Using the results of forcing on the structure from regular wave tests, drag and inertia coefficients for use in the Morison equation were determined for each separate component and configuration of the structure. These force coefficients were plotted against various wave properties to analyze correlations with wave conditions. Finally, the force coefficients for the structure were used with the Morison equation and current data from the experiments to successfully model forcing on the structure during irregular wave tests.

Combustion supervision by evaluating flywheel speed variations is a common approach in the automotive industry. This often involves preliminary measurements. An adequate model for simulating flywheel speed can assist to avoid some of these preliminary measurements. A physical nonlinear model for simulating flywheel speed based on cylinder pressure information is investigated in this work. Measurements were conducted at Scania in a test bed and on a chassis dynamometer. The model was implemented in MATLAB/Simulink and simulations are compared to measured data. The first model can not explain all dynamics for the measurements in the test bed so extended models are examined. A model using a dynamically equivalent model of the crank-slider mechanism shows no difference from the simple model, whereas a model including a driveline can explain more from the test-bed measurements. When simulating the setups used at the chassis dynamometer, the simplest model works best. Yet, it is not very accurate and it is proposed that optimization of parameter values might improve the model further. A sensitivity analysis shows that the model is fairly robust to parameter changes. A continuation of this work might include optimization to estimate parameter values in the model. Investigating methods for combustion supervision may also be a future issue.

The sediment resuspension and turbidity created during dredging operations is both an economical and environmental issue. The movement of sediment plumes created from dredging operations has been predicted with numerical modeling, however, these far-field models need a “source term” or near-field model as input. Although data from field tests have been used to create near-field models that predict the amount of material suspended in the water column, these results are skewed due to limitations such as non-uniform sediment distributions, water currents, and water quality issues. Laboratory investigations have obtained data for turbidity during dredging operations, but these results do not take advantage of the most contemporary testing methods. The purpose of this dissertation is to provide an estimation of turbidity created during a cutter suction dredging operation. This estimation was facilited by the development of resuspension measurement and data acquisition techniques in a laboratory setting. Near-field turbidity measurements around the cutter head were measured in the Haynes Coastal Engineering Laboratory at Texas A&M University. The laboratory contains a dredge/tow tank that is ideal for conducting dredging research. A dredge carriage is located in the dredge/tow tank and is composed of a carriage, cradle, and ladder. Acoustic Doppler Velocimetry (ADV) and Optical Backscatter Sensor (OBS) measurements were taken at specific points around the cutter head. The variables of suction flow rate, cutter speed, and the thickness of cut were investigated to understand their specific effect on turbidity generation and turbulence production around the cutter head. A near-field advection diffusion model was created to predict resuspension of sediment from a cutter suction dredge. The model incorporates the laboratory data to determine the velocity field as well as the turbulent diffusion. The model is validated with laboratory testing as well as field data. Conclusions from this research demonstrate undercutting consistently produced larger point specific turbidity maximum than overcutting in the laboratory testing. An increase in suction flow rate was shown to increase production and decrease turbidity around the cutter head. In general, an increase in cutter speed led to an increase in turbidity. The thickness of cut produced less resuspension for a full cut versus a partial cut. Data for a “shallow cut” also produced less turbidity generation than partial cuts. The numerical model was compared to all laboratory testing cases as well as the Calumet Harbor and New Bedford cutter resuspension data and produced suitable MRA values for all tests. The numerical model produced higher point specific regions of turbidity for undercutting but produced larger mean values of turbidity for overcutting.

Sea water intake structures submerged in the surf zone are used to provide water for cooling processes in large facilities such as power plants and refineries. Structures submerged in the surf zone are subject to large forces from breaking waves. To study these forces induced from realistic sea state conditions, a physical model of an intake structure submerged in the wave breaking zone was constructed and subjected to a wide spectrum of regular and irregular waves. The model structure was designed in a manner so force measurement could be isolated to separate components of the structure. The data of peak forces on the structure was analyzed for correlations with varying irregular wave properties. Using the results of forcing on the structure from regular wave tests, drag and inertia coefficients for use in the Morison equation were determined for each separate component and configuration of the structure. These force coefficients were plotted against various wave properties to analyze correlations with wave conditions. Finally, the force coefficients for the structure were used with the Morison equation and current data from the experiments to successfully model forcing on the structure during irregular wave tests.

Les dispositifs dédiés à l’analyse de gaz ont de nombreuses applications, notamment le contrôle de la qualité de l’air et des gaz naturels ou industriels, ou l’étude des gaz respiratoires. Le LETI travaille en collaboration avec la société APIX sur une nouvelle génération de dispositifs microsystèmes combinant des étapes de préparation des échantillons, de séparation des composants gazeux par des dispositifs de microchromatographie intégrés sur silicium, et de transduction par des détecteurs NEMS (Nano Electro Mechanical Systems) à base de nanocantilevers utilisés comme des détecteurs dits gravimétriques. Ces capteurs NEMS sont constitués de nano poutres vibrantes dont la fréquence de résonance dépend de la masse de matière déposée sur la poutre. Ces poutres sont fonctionnalisées avec un matériau capable d’adsorber puis de désorber certains composants ciblés. Lors du passage d’une impulsion de matière dans la colonne chromatographique au niveau d’un NEMS, le signal, défini par sa fréquence de résonance instantanée en fonction du temps, varie. Le pic observé sur ce signal traduira le pic de matière dans la colonne et permettra d’estimer la concentration du composant. Partant de l’ensemble des signaux mesurés sur l’ensemble des capteurs, l’objectif du traitement du signal est de fournir le profil moléculaire, c’est-à-dire la concentration de chaque composant, et d’estimer le pouvoir calorifique supérieur (PCS) associé. Le défi est d’associer une haute sensibilité pour détecter de très petites quantités de composants, et des capacités de séparation efficaces pour s’affranchir de la complexité du mélange et identifier la signature des molécules ciblées. L’objectif de cette thèse en traitement du signal est de travailler sur la formalisation des problèmes d’analyse des signaux abordés et d’étendre notre méthodologie d’analyse reposant sur l’approche problème inverse associée à un modèle hiérarchique de la chaîne d’analyse, aux dispositifs de microchromatographie gazeuse intégrant des capteurs NEMS multiples. La première application visée est le suivi du pouvoir calorifique d’un gaz naturel. Les ruptures concernent notamment la décomposition de signaux NEMS, la fusion multi-capteurs, l’autocalibrage et le suivi dynamique temporel. Le travail comportera des phases d’expérimentation réalisées notamment sur le banc d’analyse de gaz du laboratoire commun APIX-LETI. / The chromatography is a chemical technique to separate entities from a mixture. In this thesis, we will focused on the gaseous mixture, and particularly on the signal processing of gas chromatography. To acquire those signal we use different sensors. However whatever the sensor used, we obtain a peaks succession, where each peak corresponds to an entity present in the mixture. Our aim is then to analyze gaseous mixtures from acquired signals, by characterizing each peaks. After a bibliographic survey of the chromatography, we chose the Giddings and Eyring distribution to describe a peak shape. This distribution define the probability that a molecule walking randomly through the chromatographic column go out at a given time. Then we propose analytical model of the chromatographic signal which corresponds to a peak shape mixture model. Also in first approximation, this model is considered as Gaussian mixture model. To process those signals, we studied two broad groups of methods, executed upon real data and simulated data. The first family of algorithms consists in a Bayesian estimation of unknown parameters of our model. The order of mixture model can be include in the unknown parameters. It corresponds also to the number of entity in the gaseous mixture. To estimate those parameters, we use a Gibbs sampler, and Markov Chain Monte Carlo sampling, or a variational approach. The second methods consists in a sparse representation of the signal upon a dictionary. This dictionary includes a large set of peak shapes. The sparsity is then characterized by the number of components of the dictionary needed to describe the signal. At last we propose a sparse Bayesian method.

A importância de um escoamento adequado em distribuidores de lingotamento contínuo, quando o objetivo é produzir aços limpos (clean steels), vem sendo largamente discutida e estudada nas últimas décadas. Esses estudos usualmente são realizados em modelos físicos e/ou numéricos, visto que em unidades industriais são de difícil execução. Nos modelos físicos, os estudos como a simulação da remoção de inclusões para diferentes condições de escoamento tem se mostrado bastante importante para o entendimento do escoamento no distribuidor e seus respectivos artifícios favorecedores de flotação de inclusões. Este trabalho tem como objetivo estudar o comportamento da remoção de inclusões em um modelo físico do distribuidor de lingotamento contínuo de tarugos frente à modificação de escoamento no distribuidor. O ensaio proposto para quantificar a remoção de inclusões envolve a utilização de micropartículas de polietileno para simulação das inclusões sólidas de alumina e peneira metálica como método de captura de inclusões passantes pelo veio do distribuidor. Para fornecer suporte a este estudo, foram realizados estudos de qualificação do escoamento por meio do ensaio de linhas de fluxo e de quantificação dos tempos de residência e frações de volumes característicos por meio do ensaio de distribuição de tempos de residência. A técnica utilizada se mostrou confiável sob o ponto de vista experimental. Como resultados do comportamento da remoção de inclusões frente aos parâmetros estudados, têm-se especificamente para o distribuidor estudado que: o aumento da velocidade de lingotamento, em média, aumentou o porcentual de inclusões passantes de 11,61 (1,8 m/min) para 17,45% (2,6 m/min); a presença do tubo longo, em média, aumentou o porcentual de inclusões passantes de 2,79 (sem tubo longo) para 27,03% (com tubo longo); a presença das barreiras, em média, diminuiu o porcentual de inclusões passantes de 16,16 (sem barreiras) para 13,65% (com barreiras). / When the objective is to produce clean steels, the appropriated melt flow in the tundish is very important. It has been widely discussed and studied by researchers in the lasts decades. Physical and/or mathematical models are used to perform these studies because is very difficult to do it in industrial plants. In the physical models, the studies as the simulation of inclusion removal to different conditions of fluid flow have showed to be very important to understand the tundish and its respective tools to improve the inclusion removal. This work aims to study the behavior of inclusion flotation in a physical model of continuous casting tundish of steel billets in different kinds of fluid flow. The method proposed to quantify the inclusion removal involves the utilization of microparticles of polyethylene to simulate solid alumina inclusion and a metallic sieve in the strand as a method to catch the non-floated inclusions. The quantification of inclusion removal has the support of two others experiments to qualify de flow pattern by visual observation using dye tracer and quantify the residence time distribution of the model using acid tracer. The method used in this work to quantify inclusion removal showed to be reliable from an experimental point of view. As results of the behavior of the inclusion removal, the speed of ingoting increased the non-floated inclusions from 11.61 (1.8 m/min) to 17.45% (2.6 m/min), the presence of the submerged inlet shroud increased the non-floated inclusions from 2.79 (without) to 27.03% (with) and the presence of the dams the non-floated inclusions decreased from 16.16 (without) to 13.65% (with).

A importância de um escoamento adequado em distribuidores de lingotamento contínuo, quando o objetivo é produzir aços limpos (clean steels), vem sendo largamente discutida e estudada nas últimas décadas. Esses estudos usualmente são realizados em modelos físicos e/ou numéricos, visto que em unidades industriais são de difícil execução. Nos modelos físicos, os estudos como a simulação da remoção de inclusões para diferentes condições de escoamento tem se mostrado bastante importante para o entendimento do escoamento no distribuidor e seus respectivos artifícios favorecedores de flotação de inclusões. Este trabalho tem como objetivo estudar o comportamento da remoção de inclusões em um modelo físico do distribuidor de lingotamento contínuo de tarugos frente à modificação de escoamento no distribuidor. O ensaio proposto para quantificar a remoção de inclusões envolve a utilização de micropartículas de polietileno para simulação das inclusões sólidas de alumina e peneira metálica como método de captura de inclusões passantes pelo veio do distribuidor. Para fornecer suporte a este estudo, foram realizados estudos de qualificação do escoamento por meio do ensaio de linhas de fluxo e de quantificação dos tempos de residência e frações de volumes característicos por meio do ensaio de distribuição de tempos de residência. A técnica utilizada se mostrou confiável sob o ponto de vista experimental. Como resultados do comportamento da remoção de inclusões frente aos parâmetros estudados, têm-se especificamente para o distribuidor estudado que: o aumento da velocidade de lingotamento, em média, aumentou o porcentual de inclusões passantes de 11,61 (1,8 m/min) para 17,45% (2,6 m/min); a presença do tubo longo, em média, aumentou o porcentual de inclusões passantes de 2,79 (sem tubo longo) para 27,03% (com tubo longo); a presença das barreiras, em média, diminuiu o porcentual de inclusões passantes de 16,16 (sem barreiras) para 13,65% (com barreiras). / When the objective is to produce clean steels, the appropriated melt flow in the tundish is very important. It has been widely discussed and studied by researchers in the lasts decades. Physical and/or mathematical models are used to perform these studies because is very difficult to do it in industrial plants. In the physical models, the studies as the simulation of inclusion removal to different conditions of fluid flow have showed to be very important to understand the tundish and its respective tools to improve the inclusion removal. This work aims to study the behavior of inclusion flotation in a physical model of continuous casting tundish of steel billets in different kinds of fluid flow. The method proposed to quantify the inclusion removal involves the utilization of microparticles of polyethylene to simulate solid alumina inclusion and a metallic sieve in the strand as a method to catch the non-floated inclusions. The quantification of inclusion removal has the support of two others experiments to qualify de flow pattern by visual observation using dye tracer and quantify the residence time distribution of the model using acid tracer. The method used in this work to quantify inclusion removal showed to be reliable from an experimental point of view. As results of the behavior of the inclusion removal, the speed of ingoting increased the non-floated inclusions from 11.61 (1.8 m/min) to 17.45% (2.6 m/min), the presence of the submerged inlet shroud increased the non-floated inclusions from 2.79 (without) to 27.03% (with) and the presence of the dams the non-floated inclusions decreased from 16.16 (without) to 13.65% (with).